intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

528 files changed, 189532 insertions, 0 deletions

diff --git a/contrib/libs/cxxsupp/libcxx/.clang-format b/contrib/libs/cxxsupp/libcxx/.clang-format
new file mode 100644
index 00000000000..4598f60a009
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/.clang-format
@@ -0,0 +1,19 @@
+BasedOnStyle: LLVM
+
+---
+Language: Cpp
+Standard: Cpp03
+
+AlwaysBreakTemplateDeclarations: true
+PointerAlignment: Left
+
+# Disable formatting options which may break tests.
+SortIncludes: false
+ReflowComments: false
+
+# libc++'s preferred indentions of preprocessor statements.
+IndentPPDirectives: AfterHash
+
+# libc++ has some long names so we need more than the 80 column limit imposed by LLVM style, for sensible formatting
+ColumnLimit: 120
+---
diff --git a/contrib/libs/cxxsupp/libcxx/.yandex_meta/devtools.copyrights.report b/contrib/libs/cxxsupp/libcxx/.yandex_meta/devtools.copyrights.report
new file mode 100644
index 00000000000..59ae9862241
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/.yandex_meta/devtools.copyrights.report
@@ -0,0 +1,70 @@
+# File format ($ symbol means the beginning of a line):
+#
+# $ # this message
+# $ # =======================
+# $     # comments (all commentaries should starts with some number of spaces and # symbol)
+# ${action} {license id} {license text hash}
+# $BELONGS ./ya/make/file/relative/path/1/ya.make ./ya/make/2/ya.make
+# ${all_file_action} filename
+# $ # user commentaries (many lines)
+# $ generated description - files with this license, license text... (some number of lines that starts with some number of spaces, do not modify)
+# ${action} {license spdx} {license text hash}
+# $BELONGS ./ya/make/file/relative/path/3/ya.make
+# ${all_file_action} filename
+# $    #    user commentaries
+# $ generated description
+# $ ...
+#
+# You can modify action, all_file_action and add commentaries
+# Available actions:
+# keep - keep license in contrib and use in credits
+# skip - skip license
+# remove - remove all files with this license
+# rename - save license text/links into licenses texts file, but not store SPDX into LINCENSE macro. You should store correct license id into devtools.license.spdx.txt file
+#
+# {all file action} records will be generated when license text contains filename that exists on filesystem (in contrib directory)
+# We suppose that that files can contain some license info
+# Available all file actions:
+# FILE_IGNORE - ignore file (do nothing)
+# FILE_INCLUDE - include all file data into licenses text file
+# =======================
+
+KEEP     COPYRIGHT_SERVICE_LABEL 7e6a182a2f65f965d96f2755976c1829
+BELONGS ya.make
+    License text:
+         * FreeBSD libc.  These are covered by the following copyright:
+         *
+         * Copyright (c) 2002-2004 Tim J. Robbins.
+    Scancode info:
+        Original SPDX id: COPYRIGHT_SERVICE_LABEL
+        Score           : 100.00
+        Match type      : COPYRIGHT
+    Files with this license:
+        src/support/solaris/mbsnrtowcs.inc [5:7]
+        src/support/solaris/wcsnrtombs.inc [2:2]
+
+KEEP     COPYRIGHT_SERVICE_LABEL ebc015cad7377d32e7b2fc0ae5293aa1
+BELONGS ya.make
+FILE_INCLUDE CREDITS.TXT found in files: LICENSE.TXT at line 252
+    # libcxxabi/CREDITS.TXT included in libcxxabi
+    License text:
+        Copyright (c) 2009-2019 by the contributors listed in CREDITS.TXT
+    Scancode info:
+        Original SPDX id: COPYRIGHT_SERVICE_LABEL
+        Score           : 100.00
+        Match type      : COPYRIGHT
+    Files with this license:
+        LICENSE.TXT [252:252]
+
+KEEP     COPYRIGHT_SERVICE_LABEL f52c727d32a7eaf5a8de6bc96b82797c
+BELONGS ya.make
+FILE_INCLUDE CREDITS.TXT found in files: LICENSE.TXT at line 293
+    # libcxxabi/CREDITS.TXT included in libcxxabi
+    License text:
+        Copyright (c) 2009-2014 by the contributors listed in CREDITS.TXT
+    Scancode info:
+        Original SPDX id: COPYRIGHT_SERVICE_LABEL
+        Score           : 100.00
+        Match type      : COPYRIGHT
+    Files with this license:
+        LICENSE.TXT [293:293]
diff --git a/contrib/libs/cxxsupp/libcxx/.yandex_meta/devtools.licenses.report b/contrib/libs/cxxsupp/libcxx/.yandex_meta/devtools.licenses.report
new file mode 100644
index 00000000000..179b4429133
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/.yandex_meta/devtools.licenses.report
@@ -0,0 +1,2288 @@
+# File format ($ symbol means the beginning of a line):
+#
+# $ # this message
+# $ # =======================
+# $     # comments (all commentaries should starts with some number of spaces and # symbol)
+# ${action} {license spdx} {license text hash}
+# $BELONGS ./ya/make/file/relative/path/1/ya.make ./ya/make/2/ya.make
+# ${all_file_action} filename
+# $ # user commentaries (many lines)
+# $ generated description - files with this license, license text... (some number of lines that starts with some number of spaces, do not modify)
+# ${action} {license spdx} {license text hash}
+# $BELONGS ./ya/make/file/relative/path/3/ya.make
+# ${all_file_action} filename
+# $    #    user commentaries
+# $ generated description
+# $ ...
+#
+# You can modify action, all_file_action and add commentaries
+# Available actions:
+# keep - keep license in contrib and use in credits
+# skip - skip license
+# remove - remove all files with this license
+# rename - save license text/links into licenses texts file, but not store SPDX into LINCENSE macro. You should store correct license id into devtools.license.spdx.txt file
+#
+# {all file action} records will be generated when license text contains filename that exists on filesystem (in contrib directory)
+# We suppose that that files can contain some license info
+# Available all file actions:
+# FILE_IGNORE - ignore file (do nothing)
+# FILE_INCLUDE - include all file data into licenses text file
+# =======================
+
+KEEP     NCSA AND MIT         1f7e00acb6cda5de868d4d4c1ffe3c2b
+BELONGS ya.make
+    Note: matched license text is too long. Read it in the source files.
+    Scancode info:
+        Original SPDX id: NCSA
+        Score           : 100.00
+        Match type      : NOTICE
+        Links           : http://www.otm.illinois.edu/faculty/forms/opensource.asp, https://spdx.org/licenses/NCSA
+    Files with this license:
+        LICENSE.TXT [240:245]
+    Scancode info:
+        Original SPDX id: MIT
+        Score           : 100.00
+        Match type      : NOTICE
+        Links           : http://opensource.org/licenses/mit-license.php, https://spdx.org/licenses/MIT
+    Files with this license:
+        LICENSE.TXT [240:245]
+
+KEEP     NCSA                 5a35b4c0d3b3923cac31a5a371332ca2
+BELONGS ya.make
+    License text:
+        Legacy LLVM License (https://llvm.org/docs/DeveloperPolicy.html#legacy):
+    Scancode info:
+        Original SPDX id: NCSA
+        Score           : 100.00
+        Match type      : REFERENCE
+        Links           : http://www.otm.illinois.edu/faculty/forms/opensource.asp, https://spdx.org/licenses/NCSA
+    Files with this license:
+        LICENSE.TXT [237:237]
+
+KEEP     MIT                  5debb370f50e1dfd24ff5144233a2ef6
+BELONGS ya.make
+FILE_INCLUDE include/any found in files: LICENSE.TXT at line 295
+    # any - just word, not file reference
+    Note: matched license text is too long. Read it in the source files.
+    Scancode info:
+        Original SPDX id: MIT
+        Score           : 100.00
+        Match type      : TEXT
+        Links           : http://opensource.org/licenses/mit-license.php, https://spdx.org/licenses/MIT
+    Files with this license:
+        LICENSE.TXT [295:311]
+
+KEEP     Apache-2.0 WITH LLVM-exception 705a75a25bce12b12334e8fc577d8a46
+BELONGS ya.make
+    License text:
+         * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+         * See https://llvm.org/LICENSE.txt for license information.
+    Scancode info:
+        Original SPDX id: Apache-2.0
+        Score           : 100.00
+        Match type      : NOTICE
+        Links           : http://www.apache.org/licenses/, http://www.apache.org/licenses/LICENSE-2.0, https://spdx.org/licenses/Apache-2.0
+    Files with this license:
+        src/filesystem/int128_builtins.cpp [3:4]
+    Scancode info:
+        Original SPDX id: LLVM-exception
+        Score           : 100.00
+        Match type      : NOTICE
+        Links           : http://llvm.org/foundation/relicensing/LICENSE.txt, https://spdx.org/licenses/LLVM-exception
+    Files with this license:
+        src/filesystem/int128_builtins.cpp [3:4]
+
+KEEP     Apache-2.0 WITH LLVM-exception 755ab7da3ff8c5d6ae90bdbebd177e49
+BELONGS ya.make
+    License text:
+        // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+        // See https://llvm.org/LICENSE.txt for license information.
+    Scancode info:
+        Original SPDX id: Apache-2.0
+        Score           : 100.00
+        Match type      : NOTICE
+        Links           : http://www.apache.org/licenses/, http://www.apache.org/licenses/LICENSE-2.0, https://spdx.org/licenses/Apache-2.0
+    Files with this license:
+        include/__algorithm/adjacent_find.h [4:5]
+        include/__algorithm/all_of.h [4:5]
+        include/__algorithm/any_of.h [4:5]
+        include/__algorithm/binary_search.h [3:4]
+        include/__algorithm/clamp.h [3:4]
+        include/__algorithm/comp.h [3:4]
+        include/__algorithm/comp_ref_type.h [3:4]
+        include/__algorithm/copy.h [3:4]
+        include/__algorithm/copy_backward.h [3:4]
+        include/__algorithm/copy_if.h [3:4]
+        include/__algorithm/copy_n.h [3:4]
+        include/__algorithm/count.h [4:5]
+        include/__algorithm/count_if.h [4:5]
+        include/__algorithm/equal.h [4:5]
+        include/__algorithm/equal_range.h [3:4]
+        include/__algorithm/fill.h [3:4]
+        include/__algorithm/fill_n.h [3:4]
+        include/__algorithm/find.h [4:5]
+        include/__algorithm/find_end.h [4:5]
+        include/__algorithm/find_first_of.h [4:5]
+        include/__algorithm/find_if.h [4:5]
+        include/__algorithm/find_if_not.h [4:5]
+        include/__algorithm/for_each.h [4:5]
+        include/__algorithm/for_each_n.h [4:5]
+        include/__algorithm/generate.h [3:4]
+        include/__algorithm/generate_n.h [3:4]
+        include/__algorithm/half_positive.h [3:4]
+        include/__algorithm/includes.h [3:4]
+        include/__algorithm/inplace_merge.h [3:4]
+        include/__algorithm/is_heap.h [3:4]
+        include/__algorithm/is_heap_until.h [3:4]
+        include/__algorithm/is_partitioned.h [3:4]
+        include/__algorithm/is_permutation.h [4:5]
+        include/__algorithm/is_sorted.h [3:4]
+        include/__algorithm/is_sorted_until.h [3:4]
+        include/__algorithm/iter_swap.h [3:4]
+        include/__algorithm/lexicographical_compare.h [3:4]
+        include/__algorithm/lower_bound.h [3:4]
+        include/__algorithm/make_heap.h [3:4]
+        include/__algorithm/max.h [3:4]
+        include/__algorithm/max_element.h [3:4]
+        include/__algorithm/merge.h [3:4]
+        include/__algorithm/min.h [3:4]
+        include/__algorithm/min_element.h [3:4]
+        include/__algorithm/minmax.h [3:4]
+        include/__algorithm/minmax_element.h [3:4]
+        include/__algorithm/mismatch.h [4:5]
+        include/__algorithm/move.h [3:4]
+        include/__algorithm/move_backward.h [3:4]
+        include/__algorithm/next_permutation.h [3:4]
+        include/__algorithm/none_of.h [4:5]
+        include/__algorithm/nth_element.h [3:4]
+        include/__algorithm/partial_sort.h [3:4]
+        include/__algorithm/partial_sort_copy.h [3:4]
+        include/__algorithm/partition.h [3:4]
+        include/__algorithm/partition_copy.h [3:4]
+        include/__algorithm/partition_point.h [3:4]
+        include/__algorithm/pop_heap.h [3:4]
+        include/__algorithm/prev_permutation.h [3:4]
+        include/__algorithm/push_heap.h [3:4]
+        include/__algorithm/remove.h [3:4]
+        include/__algorithm/remove_copy.h [3:4]
+        include/__algorithm/remove_copy_if.h [3:4]
+        include/__algorithm/remove_if.h [3:4]
+        include/__algorithm/replace.h [3:4]
+        include/__algorithm/replace_copy.h [3:4]
+        include/__algorithm/replace_copy_if.h [3:4]
+        include/__algorithm/replace_if.h [3:4]
+        include/__algorithm/reverse.h [3:4]
+        include/__algorithm/reverse_copy.h [3:4]
+        include/__algorithm/rotate.h [3:4]
+        include/__algorithm/rotate_copy.h [3:4]
+        include/__algorithm/sample.h [3:4]
+        include/__algorithm/search.h [4:5]
+        include/__algorithm/search_n.h [4:5]
+        include/__algorithm/set_difference.h [3:4]
+        include/__algorithm/set_intersection.h [3:4]
+        include/__algorithm/set_symmetric_difference.h [3:4]
+        include/__algorithm/set_union.h [3:4]
+        include/__algorithm/shift_left.h [3:4]
+        include/__algorithm/shift_right.h [3:4]
+        include/__algorithm/shuffle.h [3:4]
+        include/__algorithm/sift_down.h [3:4]
+        include/__algorithm/sort.h [3:4]
+        include/__algorithm/sort_heap.h [3:4]
+        include/__algorithm/stable_partition.h [3:4]
+        include/__algorithm/stable_sort.h [3:4]
+        include/__algorithm/swap_ranges.h [3:4]
+        include/__algorithm/transform.h [3:4]
+        include/__algorithm/unique.h [3:4]
+        include/__algorithm/unique_copy.h [3:4]
+        include/__algorithm/unwrap_iter.h [3:4]
+        include/__algorithm/upper_bound.h [3:4]
+        include/__availability [4:5]
+        include/__bit/bit_cast.h [4:5]
+        include/__bit_reference [4:5]
+        include/__bits [4:5]
+        include/__bsd_locale_defaults.h [4:5]
+        include/__bsd_locale_fallbacks.h [4:5]
+        include/__charconv/chars_format.h [4:5]
+        include/__charconv/from_chars_result.h [4:5]
+        include/__charconv/to_chars_result.h [4:5]
+        include/__compare/common_comparison_category.h [3:4]
+        include/__compare/compare_three_way_result.h [3:4]
+        include/__compare/ordering.h [3:4]
+        include/__compare/synth_three_way.h [3:4]
+        include/__compare/three_way_comparable.h [3:4]
+        include/__concepts/arithmetic.h [3:4]
+        include/__concepts/assignable.h [3:4]
+        include/__concepts/boolean_testable.h [3:4]
+        include/__concepts/class_or_enum.h [3:4]
+        include/__concepts/common_reference_with.h [3:4]
+        include/__concepts/common_with.h [3:4]
+        include/__concepts/constructible.h [3:4]
+        include/__concepts/convertible_to.h [3:4]
+        include/__concepts/copyable.h [3:4]
+        include/__concepts/derived_from.h [3:4]
+        include/__concepts/destructible.h [3:4]
+        include/__concepts/different_from.h [3:4]
+        include/__concepts/equality_comparable.h [3:4]
+        include/__concepts/invocable.h [3:4]
+        include/__concepts/movable.h [3:4]
+        include/__concepts/predicate.h [3:4]
+        include/__concepts/regular.h [3:4]
+        include/__concepts/relation.h [3:4]
+        include/__concepts/same_as.h [3:4]
+        include/__concepts/semiregular.h [3:4]
+        include/__concepts/swappable.h [3:4]
+        include/__concepts/totally_ordered.h [3:4]
+        include/__config [4:5]
+        include/__config_site.in [3:4]
+        include/__debug [4:5]
+        include/__errc [4:5]
+        include/__format/format_arg.h [4:5]
+        include/__format/format_args.h [4:5]
+        include/__format/format_context.h [4:5]
+        include/__format/format_error.h [4:5]
+        include/__format/format_fwd.h [4:5]
+        include/__format/format_parse_context.h [4:5]
+        include/__format/format_string.h [4:5]
+        include/__format/formatter.h [4:5]
+        include/__format/parser_std_format_spec.h [4:5]
+        include/__function_like.h [4:5]
+        include/__functional/binary_function.h [4:5]
+        include/__functional/binary_negate.h [4:5]
+        include/__functional/bind.h [4:5]
+        include/__functional/bind_back.h [4:5]
+        include/__functional/bind_front.h [4:5]
+        include/__functional/binder1st.h [4:5]
+        include/__functional/binder2nd.h [4:5]
+        include/__functional/compose.h [4:5]
+        include/__functional/default_searcher.h [4:5]
+        include/__functional/function.h [4:5]
+        include/__functional/hash.h [3:4]
+        include/__functional/identity.h [4:5]
+        include/__functional/invoke.h [4:5]
+        include/__functional/is_transparent.h [4:5]
+        include/__functional/mem_fn.h [4:5]
+        include/__functional/mem_fun_ref.h [4:5]
+        include/__functional/not_fn.h [4:5]
+        include/__functional/operations.h [4:5]
+        include/__functional/perfect_forward.h [4:5]
+        include/__functional/pointer_to_binary_function.h [4:5]
+        include/__functional/pointer_to_unary_function.h [4:5]
+        include/__functional/ranges_operations.h [4:5]
+        include/__functional/reference_wrapper.h [4:5]
+        include/__functional/unary_function.h [3:4]
+        include/__functional/unary_negate.h [4:5]
+        include/__functional/unwrap_ref.h [3:4]
+        include/__functional/weak_result_type.h [4:5]
+        include/__functional_base [4:5]
+        include/__hash_table [4:5]
+        include/__iterator/access.h [4:5]
+        include/__iterator/advance.h [4:5]
+        include/__iterator/back_insert_iterator.h [4:5]
+        include/__iterator/common_iterator.h [4:5]
+        include/__iterator/concepts.h [4:5]
+        include/__iterator/counted_iterator.h [4:5]
+        include/__iterator/data.h [4:5]
+        include/__iterator/default_sentinel.h [4:5]
+        include/__iterator/distance.h [4:5]
+        include/__iterator/empty.h [4:5]
+        include/__iterator/erase_if_container.h [4:5]
+        include/__iterator/front_insert_iterator.h [4:5]
+        include/__iterator/incrementable_traits.h [4:5]
+        include/__iterator/insert_iterator.h [4:5]
+        include/__iterator/istream_iterator.h [4:5]
+        include/__iterator/istreambuf_iterator.h [4:5]
+        include/__iterator/iter_move.h [4:5]
+        include/__iterator/iter_swap.h [4:5]
+        include/__iterator/iterator.h [4:5]
+        include/__iterator/iterator_traits.h [4:5]
+        include/__iterator/move_iterator.h [4:5]
+        include/__iterator/next.h [4:5]
+        include/__iterator/ostream_iterator.h [4:5]
+        include/__iterator/ostreambuf_iterator.h [4:5]
+        include/__iterator/prev.h [4:5]
+        include/__iterator/projected.h [4:5]
+        include/__iterator/readable_traits.h [4:5]
+        include/__iterator/reverse_access.h [4:5]
+        include/__iterator/reverse_iterator.h [4:5]
+        include/__iterator/size.h [4:5]
+        include/__iterator/unreachable_sentinel.h [4:5]
+        include/__iterator/wrap_iter.h [4:5]
+        include/__locale [4:5]
+        include/__memory/addressof.h [4:5]
+        include/__memory/allocation_guard.h [4:5]
+        include/__memory/allocator.h [4:5]
+        include/__memory/allocator_arg_t.h [4:5]
+        include/__memory/allocator_traits.h [4:5]
+        include/__memory/auto_ptr.h [4:5]
+        include/__memory/compressed_pair.h [4:5]
+        include/__memory/construct_at.h [4:5]
+        include/__memory/pointer_safety.h [4:5]
+        include/__memory/pointer_traits.h [4:5]
+        include/__memory/raw_storage_iterator.h [4:5]
+        include/__memory/shared_ptr.h [4:5]
+        include/__memory/temporary_buffer.h [4:5]
+        include/__memory/uninitialized_algorithms.h [4:5]
+        include/__memory/unique_ptr.h [4:5]
+        include/__memory/uses_allocator.h [4:5]
+        include/__mutex_base [4:5]
+        include/__node_handle [4:5]
+        include/__nullptr [4:5]
+        include/__random/uniform_int_distribution.h [3:4]
+        include/__ranges/access.h [4:5]
+        include/__ranges/all.h [4:5]
+        include/__ranges/common_view.h [4:5]
+        include/__ranges/concepts.h [4:5]
+        include/__ranges/copyable_box.h [4:5]
+        include/__ranges/counted.h [4:5]
+        include/__ranges/dangling.h [4:5]
+        include/__ranges/data.h [4:5]
+        include/__ranges/drop_view.h [4:5]
+        include/__ranges/empty.h [4:5]
+        include/__ranges/empty_view.h [4:5]
+        include/__ranges/enable_borrowed_range.h [4:5]
+        include/__ranges/enable_view.h [4:5]
+        include/__ranges/iota_view.h [4:5]
+        include/__ranges/join_view.h [4:5]
+        include/__ranges/non_propagating_cache.h [4:5]
+        include/__ranges/range_adaptor.h [4:5]
+        include/__ranges/ref_view.h [4:5]
+        include/__ranges/reverse_view.h [4:5]
+        include/__ranges/single_view.h [4:5]
+        include/__ranges/size.h [4:5]
+        include/__ranges/subrange.h [4:5]
+        include/__ranges/take_view.h [4:5]
+        include/__ranges/transform_view.h [4:5]
+        include/__ranges/view_interface.h [4:5]
+        include/__std_stream [4:5]
+        include/__string [4:5]
+        include/__support/android/locale_bionic.h [4:5]
+        include/__support/fuchsia/xlocale.h [4:5]
+        include/__support/ibm/gettod_zos.h [4:5]
+        include/__support/ibm/limits.h [4:5]
+        include/__support/ibm/locale_mgmt_zos.h [4:5]
+        include/__support/ibm/nanosleep.h [4:5]
+        include/__support/ibm/support.h [4:5]
+        include/__support/ibm/xlocale.h [4:5]
+        include/__support/musl/xlocale.h [4:5]
+        include/__support/newlib/xlocale.h [3:4]
+        include/__support/openbsd/xlocale.h [4:5]
+        include/__support/solaris/floatingpoint.h [3:4]
+        include/__support/solaris/wchar.h [3:4]
+        include/__support/solaris/xlocale.h [3:4]
+        include/__support/win32/limits_msvc_win32.h [4:5]
+        include/__support/win32/locale_win32.h [4:5]
+        include/__support/xlocale/__nop_locale_mgmt.h [4:5]
+        include/__support/xlocale/__posix_l_fallback.h [4:5]
+        include/__support/xlocale/__strtonum_fallback.h [4:5]
+        include/__threading_support [4:5]
+        include/__tree [4:5]
+        include/__tuple [4:5]
+        include/__undef_macros [4:5]
+        include/__utility/as_const.h [3:4]
+        include/__utility/cmp.h [3:4]
+        include/__utility/decay_copy.h [4:5]
+        include/__utility/declval.h [3:4]
+        include/__utility/exchange.h [3:4]
+        include/__utility/forward.h [4:5]
+        include/__utility/in_place.h [3:4]
+        include/__utility/integer_sequence.h [3:4]
+        include/__utility/move.h [4:5]
+        include/__utility/pair.h [3:4]
+        include/__utility/piecewise_construct.h [3:4]
+        include/__utility/rel_ops.h [3:4]
+        include/__utility/swap.h [3:4]
+        include/__utility/to_underlying.h [4:5]
+        include/__variant/monostate.h [4:5]
+        include/algorithm [4:5]
+        include/any [4:5]
+        include/array [4:5]
+        include/atomic [4:5]
+        include/barrier [4:5]
+        include/bit [4:5]
+        include/bitset [4:5]
+        include/cassert [4:5]
+        include/ccomplex [4:5]
+        include/cctype [4:5]
+        include/cerrno [4:5]
+        include/cfenv [4:5]
+        include/cfloat [4:5]
+        include/charconv [4:5]
+        include/chrono [4:5]
+        include/cinttypes [4:5]
+        include/ciso646 [4:5]
+        include/climits [4:5]
+        include/clocale [4:5]
+        include/cmath [4:5]
+        include/codecvt [4:5]
+        include/compare [4:5]
+        include/complex [4:5]
+        include/complex.h [4:5]
+        include/concepts [4:5]
+        include/condition_variable [4:5]
+        include/csetjmp [4:5]
+        include/csignal [4:5]
+        include/cstdarg [4:5]
+        include/cstdbool [4:5]
+        include/cstddef [4:5]
+        include/cstdint [4:5]
+        include/cstdio [4:5]
+        include/cstdlib [4:5]
+        include/cstring [4:5]
+        include/ctgmath [4:5]
+        include/ctime [4:5]
+        include/ctype.h [4:5]
+        include/cwchar [4:5]
+        include/cwctype [4:5]
+        include/deque [4:5]
+        include/errno.h [4:5]
+        include/exception [4:5]
+        include/execution [4:5]
+        include/experimental/__memory [4:5]
+        include/experimental/algorithm [4:5]
+        include/experimental/coroutine [4:5]
+        include/experimental/deque [4:5]
+        include/experimental/filesystem [4:5]
+        include/experimental/forward_list [4:5]
+        include/experimental/functional [4:5]
+        include/experimental/iterator [4:5]
+        include/experimental/list [4:5]
+        include/experimental/map [4:5]
+        include/experimental/memory_resource [4:5]
+        include/experimental/propagate_const [4:5]
+        include/experimental/regex [4:5]
+        include/experimental/set [4:5]
+        include/experimental/simd [4:5]
+        include/experimental/string [4:5]
+        include/experimental/type_traits [4:5]
+        include/experimental/unordered_map [4:5]
+        include/experimental/unordered_set [4:5]
+        include/experimental/utility [4:5]
+        include/experimental/vector [4:5]
+        include/ext/__hash [4:5]
+        include/ext/hash_map [4:5]
+        include/ext/hash_set [4:5]
+        include/filesystem [4:5]
+        include/float.h [4:5]
+        include/format [4:5]
+        include/forward_list [4:5]
+        include/fstream [4:5]
+        include/functional [4:5]
+        include/future [4:5]
+        include/initializer_list [4:5]
+        include/inttypes.h [4:5]
+        include/iomanip [4:5]
+        include/ios [4:5]
+        include/iosfwd [4:5]
+        include/iostream [4:5]
+        include/istream [4:5]
+        include/iterator [4:5]
+        include/latch [4:5]
+        include/limits [4:5]
+        include/limits.h [4:5]
+        include/list [4:5]
+        include/locale [4:5]
+        include/locale.h [4:5]
+        include/map [4:5]
+        include/math.h [4:5]
+        include/memory [4:5]
+        include/mutex [4:5]
+        include/new [4:5]
+        include/numbers [4:5]
+        include/numeric [4:5]
+        include/optional [4:5]
+        include/ostream [4:5]
+        include/queue [4:5]
+        include/random [4:5]
+        include/ranges [4:5]
+        include/ratio [4:5]
+        include/regex [4:5]
+        include/scoped_allocator [4:5]
+        include/semaphore [4:5]
+        include/set [4:5]
+        include/setjmp.h [4:5]
+        include/shared_mutex [4:5]
+        include/span [4:5]
+        include/sstream [4:5]
+        include/stack [4:5]
+        include/stdbool.h [4:5]
+        include/stddef.h [4:5]
+        include/stdexcept [4:5]
+        include/stdint.h [4:5]
+        include/stdio.h [4:5]
+        include/stdlib.h [4:5]
+        include/streambuf [4:5]
+        include/string [4:5]
+        include/string.h [4:5]
+        include/string_view [4:5]
+        include/strstream [4:5]
+        include/system_error [4:5]
+        include/tgmath.h [4:5]
+        include/thread [4:5]
+        include/tuple [4:5]
+        include/type_traits [4:5]
+        include/typeindex [4:5]
+        include/typeinfo [4:5]
+        include/unordered_map [4:5]
+        include/unordered_set [4:5]
+        include/utility [4:5]
+        include/valarray [4:5]
+        include/variant [4:5]
+        include/vector [4:5]
+        include/version [4:5]
+        include/wchar.h [4:5]
+        include/wctype.h [4:5]
+        src/algorithm.cpp [3:4]
+        src/any.cpp [3:4]
+        src/atomic.cpp [3:4]
+        src/barrier.cpp [3:4]
+        src/bind.cpp [3:4]
+        src/charconv.cpp [3:4]
+        src/chrono.cpp [3:4]
+        src/condition_variable.cpp [3:4]
+        src/condition_variable_destructor.cpp [3:4]
+        src/debug.cpp [3:4]
+        src/exception.cpp [3:4]
+        src/experimental/memory_resource.cpp [3:4]
+        src/filesystem/directory_iterator.cpp [3:4]
+        src/filesystem/filesystem_common.h [3:4]
+        src/filesystem/operations.cpp [3:4]
+        src/filesystem/posix_compat.h [3:4]
+        src/format.cpp [3:4]
+        src/functional.cpp [3:4]
+        src/future.cpp [3:4]
+        src/hash.cpp [3:4]
+        src/include/apple_availability.h [3:4]
+        src/include/atomic_support.h [3:4]
+        src/include/config_elast.h [3:4]
+        src/include/refstring.h [3:4]
+        src/include/sso_allocator.h [4:5]
+        src/ios.cpp [3:4]
+        src/ios.instantiations.cpp [3:4]
+        src/iostream.cpp [3:4]
+        src/locale.cpp [3:4]
+        src/memory.cpp [3:4]
+        src/mutex.cpp [3:4]
+        src/mutex_destructor.cpp [3:4]
+        src/new.cpp [3:4]
+        src/optional.cpp [3:4]
+        src/random.cpp [3:4]
+        src/random_shuffle.cpp [3:4]
+        src/regex.cpp [3:4]
+        src/shared_mutex.cpp [3:4]
+        src/stdexcept.cpp [3:4]
+        src/string.cpp [3:4]
+        src/strstream.cpp [3:4]
+        src/support/ibm/mbsnrtowcs.cpp [3:4]
+        src/support/ibm/wcsnrtombs.cpp [3:4]
+        src/support/ibm/xlocale_zos.cpp [3:4]
+        src/support/runtime/exception_fallback.ipp [4:5]
+        src/support/runtime/exception_glibcxx.ipp [4:5]
+        src/support/runtime/exception_libcxxabi.ipp [4:5]
+        src/support/runtime/exception_libcxxrt.ipp [4:5]
+        src/support/runtime/exception_msvc.ipp [4:5]
+        src/support/runtime/exception_pointer_cxxabi.ipp [4:5]
+        src/support/runtime/exception_pointer_glibcxx.ipp [4:5]
+        src/support/runtime/exception_pointer_msvc.ipp [4:5]
+        src/support/runtime/exception_pointer_unimplemented.ipp [4:5]
+        src/support/runtime/new_handler_fallback.ipp [4:5]
+        src/support/runtime/stdexcept_default.ipp [3:4]
+        src/support/runtime/stdexcept_vcruntime.ipp [3:4]
+        src/support/solaris/xlocale.cpp [3:4]
+        src/support/win32/locale_win32.cpp [4:5]
+        src/support/win32/support.cpp [4:5]
+        src/support/win32/thread_win32.cpp [4:5]
+        src/system_error.cpp [3:4]
+        src/thread.cpp [3:4]
+        src/typeinfo.cpp [3:4]
+        src/utility.cpp [3:4]
+        src/valarray.cpp [3:4]
+        src/variant.cpp [3:4]
+        src/vector.cpp [3:4]
+    Scancode info:
+        Original SPDX id: LLVM-exception
+        Score           : 100.00
+        Match type      : NOTICE
+        Links           : http://llvm.org/foundation/relicensing/LICENSE.txt, https://spdx.org/licenses/LLVM-exception
+    Files with this license:
+        include/__algorithm/adjacent_find.h [4:5]
+        include/__algorithm/all_of.h [4:5]
+        include/__algorithm/any_of.h [4:5]
+        include/__algorithm/binary_search.h [3:4]
+        include/__algorithm/clamp.h [3:4]
+        include/__algorithm/comp.h [3:4]
+        include/__algorithm/comp_ref_type.h [3:4]
+        include/__algorithm/copy.h [3:4]
+        include/__algorithm/copy_backward.h [3:4]
+        include/__algorithm/copy_if.h [3:4]
+        include/__algorithm/copy_n.h [3:4]
+        include/__algorithm/count.h [4:5]
+        include/__algorithm/count_if.h [4:5]
+        include/__algorithm/equal.h [4:5]
+        include/__algorithm/equal_range.h [3:4]
+        include/__algorithm/fill.h [3:4]
+        include/__algorithm/fill_n.h [3:4]
+        include/__algorithm/find.h [4:5]
+        include/__algorithm/find_end.h [4:5]
+        include/__algorithm/find_first_of.h [4:5]
+        include/__algorithm/find_if.h [4:5]
+        include/__algorithm/find_if_not.h [4:5]
+        include/__algorithm/for_each.h [4:5]
+        include/__algorithm/for_each_n.h [4:5]
+        include/__algorithm/generate.h [3:4]
+        include/__algorithm/generate_n.h [3:4]
+        include/__algorithm/half_positive.h [3:4]
+        include/__algorithm/includes.h [3:4]
+        include/__algorithm/inplace_merge.h [3:4]
+        include/__algorithm/is_heap.h [3:4]
+        include/__algorithm/is_heap_until.h [3:4]
+        include/__algorithm/is_partitioned.h [3:4]
+        include/__algorithm/is_permutation.h [4:5]
+        include/__algorithm/is_sorted.h [3:4]
+        include/__algorithm/is_sorted_until.h [3:4]
+        include/__algorithm/iter_swap.h [3:4]
+        include/__algorithm/lexicographical_compare.h [3:4]
+        include/__algorithm/lower_bound.h [3:4]
+        include/__algorithm/make_heap.h [3:4]
+        include/__algorithm/max.h [3:4]
+        include/__algorithm/max_element.h [3:4]
+        include/__algorithm/merge.h [3:4]
+        include/__algorithm/min.h [3:4]
+        include/__algorithm/min_element.h [3:4]
+        include/__algorithm/minmax.h [3:4]
+        include/__algorithm/minmax_element.h [3:4]
+        include/__algorithm/mismatch.h [4:5]
+        include/__algorithm/move.h [3:4]
+        include/__algorithm/move_backward.h [3:4]
+        include/__algorithm/next_permutation.h [3:4]
+        include/__algorithm/none_of.h [4:5]
+        include/__algorithm/nth_element.h [3:4]
+        include/__algorithm/partial_sort.h [3:4]
+        include/__algorithm/partial_sort_copy.h [3:4]
+        include/__algorithm/partition.h [3:4]
+        include/__algorithm/partition_copy.h [3:4]
+        include/__algorithm/partition_point.h [3:4]
+        include/__algorithm/pop_heap.h [3:4]
+        include/__algorithm/prev_permutation.h [3:4]
+        include/__algorithm/push_heap.h [3:4]
+        include/__algorithm/remove.h [3:4]
+        include/__algorithm/remove_copy.h [3:4]
+        include/__algorithm/remove_copy_if.h [3:4]
+        include/__algorithm/remove_if.h [3:4]
+        include/__algorithm/replace.h [3:4]
+        include/__algorithm/replace_copy.h [3:4]
+        include/__algorithm/replace_copy_if.h [3:4]
+        include/__algorithm/replace_if.h [3:4]
+        include/__algorithm/reverse.h [3:4]
+        include/__algorithm/reverse_copy.h [3:4]
+        include/__algorithm/rotate.h [3:4]
+        include/__algorithm/rotate_copy.h [3:4]
+        include/__algorithm/sample.h [3:4]
+        include/__algorithm/search.h [4:5]
+        include/__algorithm/search_n.h [4:5]
+        include/__algorithm/set_difference.h [3:4]
+        include/__algorithm/set_intersection.h [3:4]
+        include/__algorithm/set_symmetric_difference.h [3:4]
+        include/__algorithm/set_union.h [3:4]
+        include/__algorithm/shift_left.h [3:4]
+        include/__algorithm/shift_right.h [3:4]
+        include/__algorithm/shuffle.h [3:4]
+        include/__algorithm/sift_down.h [3:4]
+        include/__algorithm/sort.h [3:4]
+        include/__algorithm/sort_heap.h [3:4]
+        include/__algorithm/stable_partition.h [3:4]
+        include/__algorithm/stable_sort.h [3:4]
+        include/__algorithm/swap_ranges.h [3:4]
+        include/__algorithm/transform.h [3:4]
+        include/__algorithm/unique.h [3:4]
+        include/__algorithm/unique_copy.h [3:4]
+        include/__algorithm/unwrap_iter.h [3:4]
+        include/__algorithm/upper_bound.h [3:4]
+        include/__availability [4:5]
+        include/__bit/bit_cast.h [4:5]
+        include/__bit_reference [4:5]
+        include/__bits [4:5]
+        include/__bsd_locale_defaults.h [4:5]
+        include/__bsd_locale_fallbacks.h [4:5]
+        include/__charconv/chars_format.h [4:5]
+        include/__charconv/from_chars_result.h [4:5]
+        include/__charconv/to_chars_result.h [4:5]
+        include/__compare/common_comparison_category.h [3:4]
+        include/__compare/compare_three_way_result.h [3:4]
+        include/__compare/ordering.h [3:4]
+        include/__compare/synth_three_way.h [3:4]
+        include/__compare/three_way_comparable.h [3:4]
+        include/__concepts/arithmetic.h [3:4]
+        include/__concepts/assignable.h [3:4]
+        include/__concepts/boolean_testable.h [3:4]
+        include/__concepts/class_or_enum.h [3:4]
+        include/__concepts/common_reference_with.h [3:4]
+        include/__concepts/common_with.h [3:4]
+        include/__concepts/constructible.h [3:4]
+        include/__concepts/convertible_to.h [3:4]
+        include/__concepts/copyable.h [3:4]
+        include/__concepts/derived_from.h [3:4]
+        include/__concepts/destructible.h [3:4]
+        include/__concepts/different_from.h [3:4]
+        include/__concepts/equality_comparable.h [3:4]
+        include/__concepts/invocable.h [3:4]
+        include/__concepts/movable.h [3:4]
+        include/__concepts/predicate.h [3:4]
+        include/__concepts/regular.h [3:4]
+        include/__concepts/relation.h [3:4]
+        include/__concepts/same_as.h [3:4]
+        include/__concepts/semiregular.h [3:4]
+        include/__concepts/swappable.h [3:4]
+        include/__concepts/totally_ordered.h [3:4]
+        include/__config [4:5]
+        include/__config_site.in [3:4]
+        include/__debug [4:5]
+        include/__errc [4:5]
+        include/__format/format_arg.h [4:5]
+        include/__format/format_args.h [4:5]
+        include/__format/format_context.h [4:5]
+        include/__format/format_error.h [4:5]
+        include/__format/format_fwd.h [4:5]
+        include/__format/format_parse_context.h [4:5]
+        include/__format/format_string.h [4:5]
+        include/__format/formatter.h [4:5]
+        include/__format/parser_std_format_spec.h [4:5]
+        include/__function_like.h [4:5]
+        include/__functional/binary_function.h [4:5]
+        include/__functional/binary_negate.h [4:5]
+        include/__functional/bind.h [4:5]
+        include/__functional/bind_back.h [4:5]
+        include/__functional/bind_front.h [4:5]
+        include/__functional/binder1st.h [4:5]
+        include/__functional/binder2nd.h [4:5]
+        include/__functional/compose.h [4:5]
+        include/__functional/default_searcher.h [4:5]
+        include/__functional/function.h [4:5]
+        include/__functional/hash.h [3:4]
+        include/__functional/identity.h [4:5]
+        include/__functional/invoke.h [4:5]
+        include/__functional/is_transparent.h [4:5]
+        include/__functional/mem_fn.h [4:5]
+        include/__functional/mem_fun_ref.h [4:5]
+        include/__functional/not_fn.h [4:5]
+        include/__functional/operations.h [4:5]
+        include/__functional/perfect_forward.h [4:5]
+        include/__functional/pointer_to_binary_function.h [4:5]
+        include/__functional/pointer_to_unary_function.h [4:5]
+        include/__functional/ranges_operations.h [4:5]
+        include/__functional/reference_wrapper.h [4:5]
+        include/__functional/unary_function.h [3:4]
+        include/__functional/unary_negate.h [4:5]
+        include/__functional/unwrap_ref.h [3:4]
+        include/__functional/weak_result_type.h [4:5]
+        include/__functional_base [4:5]
+        include/__hash_table [4:5]
+        include/__iterator/access.h [4:5]
+        include/__iterator/advance.h [4:5]
+        include/__iterator/back_insert_iterator.h [4:5]
+        include/__iterator/common_iterator.h [4:5]
+        include/__iterator/concepts.h [4:5]
+        include/__iterator/counted_iterator.h [4:5]
+        include/__iterator/data.h [4:5]
+        include/__iterator/default_sentinel.h [4:5]
+        include/__iterator/distance.h [4:5]
+        include/__iterator/empty.h [4:5]
+        include/__iterator/erase_if_container.h [4:5]
+        include/__iterator/front_insert_iterator.h [4:5]
+        include/__iterator/incrementable_traits.h [4:5]
+        include/__iterator/insert_iterator.h [4:5]
+        include/__iterator/istream_iterator.h [4:5]
+        include/__iterator/istreambuf_iterator.h [4:5]
+        include/__iterator/iter_move.h [4:5]
+        include/__iterator/iter_swap.h [4:5]
+        include/__iterator/iterator.h [4:5]
+        include/__iterator/iterator_traits.h [4:5]
+        include/__iterator/move_iterator.h [4:5]
+        include/__iterator/next.h [4:5]
+        include/__iterator/ostream_iterator.h [4:5]
+        include/__iterator/ostreambuf_iterator.h [4:5]
+        include/__iterator/prev.h [4:5]
+        include/__iterator/projected.h [4:5]
+        include/__iterator/readable_traits.h [4:5]
+        include/__iterator/reverse_access.h [4:5]
+        include/__iterator/reverse_iterator.h [4:5]
+        include/__iterator/size.h [4:5]
+        include/__iterator/unreachable_sentinel.h [4:5]
+        include/__iterator/wrap_iter.h [4:5]
+        include/__locale [4:5]
+        include/__memory/addressof.h [4:5]
+        include/__memory/allocation_guard.h [4:5]
+        include/__memory/allocator.h [4:5]
+        include/__memory/allocator_arg_t.h [4:5]
+        include/__memory/allocator_traits.h [4:5]
+        include/__memory/auto_ptr.h [4:5]
+        include/__memory/compressed_pair.h [4:5]
+        include/__memory/construct_at.h [4:5]
+        include/__memory/pointer_safety.h [4:5]
+        include/__memory/pointer_traits.h [4:5]
+        include/__memory/raw_storage_iterator.h [4:5]
+        include/__memory/shared_ptr.h [4:5]
+        include/__memory/temporary_buffer.h [4:5]
+        include/__memory/uninitialized_algorithms.h [4:5]
+        include/__memory/unique_ptr.h [4:5]
+        include/__memory/uses_allocator.h [4:5]
+        include/__mutex_base [4:5]
+        include/__node_handle [4:5]
+        include/__nullptr [4:5]
+        include/__random/uniform_int_distribution.h [3:4]
+        include/__ranges/access.h [4:5]
+        include/__ranges/all.h [4:5]
+        include/__ranges/common_view.h [4:5]
+        include/__ranges/concepts.h [4:5]
+        include/__ranges/copyable_box.h [4:5]
+        include/__ranges/counted.h [4:5]
+        include/__ranges/dangling.h [4:5]
+        include/__ranges/data.h [4:5]
+        include/__ranges/drop_view.h [4:5]
+        include/__ranges/empty.h [4:5]
+        include/__ranges/empty_view.h [4:5]
+        include/__ranges/enable_borrowed_range.h [4:5]
+        include/__ranges/enable_view.h [4:5]
+        include/__ranges/iota_view.h [4:5]
+        include/__ranges/join_view.h [4:5]
+        include/__ranges/non_propagating_cache.h [4:5]
+        include/__ranges/range_adaptor.h [4:5]
+        include/__ranges/ref_view.h [4:5]
+        include/__ranges/reverse_view.h [4:5]
+        include/__ranges/single_view.h [4:5]
+        include/__ranges/size.h [4:5]
+        include/__ranges/subrange.h [4:5]
+        include/__ranges/take_view.h [4:5]
+        include/__ranges/transform_view.h [4:5]
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+        include/__string [4:5]
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+        include/__support/fuchsia/xlocale.h [4:5]
+        include/__support/ibm/gettod_zos.h [4:5]
+        include/__support/ibm/limits.h [4:5]
+        include/__support/ibm/locale_mgmt_zos.h [4:5]
+        include/__support/ibm/nanosleep.h [4:5]
+        include/__support/ibm/support.h [4:5]
+        include/__support/ibm/xlocale.h [4:5]
+        include/__support/musl/xlocale.h [4:5]
+        include/__support/newlib/xlocale.h [3:4]
+        include/__support/openbsd/xlocale.h [4:5]
+        include/__support/solaris/floatingpoint.h [3:4]
+        include/__support/solaris/wchar.h [3:4]
+        include/__support/solaris/xlocale.h [3:4]
+        include/__support/win32/limits_msvc_win32.h [4:5]
+        include/__support/win32/locale_win32.h [4:5]
+        include/__support/xlocale/__nop_locale_mgmt.h [4:5]
+        include/__support/xlocale/__posix_l_fallback.h [4:5]
+        include/__support/xlocale/__strtonum_fallback.h [4:5]
+        include/__threading_support [4:5]
+        include/__tree [4:5]
+        include/__tuple [4:5]
+        include/__undef_macros [4:5]
+        include/__utility/as_const.h [3:4]
+        include/__utility/cmp.h [3:4]
+        include/__utility/decay_copy.h [4:5]
+        include/__utility/declval.h [3:4]
+        include/__utility/exchange.h [3:4]
+        include/__utility/forward.h [4:5]
+        include/__utility/in_place.h [3:4]
+        include/__utility/integer_sequence.h [3:4]
+        include/__utility/move.h [4:5]
+        include/__utility/pair.h [3:4]
+        include/__utility/piecewise_construct.h [3:4]
+        include/__utility/rel_ops.h [3:4]
+        include/__utility/swap.h [3:4]
+        include/__utility/to_underlying.h [4:5]
+        include/__variant/monostate.h [4:5]
+        include/algorithm [4:5]
+        include/any [4:5]
+        include/array [4:5]
+        include/atomic [4:5]
+        include/barrier [4:5]
+        include/bit [4:5]
+        include/bitset [4:5]
+        include/cassert [4:5]
+        include/ccomplex [4:5]
+        include/cctype [4:5]
+        include/cerrno [4:5]
+        include/cfenv [4:5]
+        include/cfloat [4:5]
+        include/charconv [4:5]
+        include/chrono [4:5]
+        include/cinttypes [4:5]
+        include/ciso646 [4:5]
+        include/climits [4:5]
+        include/clocale [4:5]
+        include/cmath [4:5]
+        include/codecvt [4:5]
+        include/compare [4:5]
+        include/complex [4:5]
+        include/complex.h [4:5]
+        include/concepts [4:5]
+        include/condition_variable [4:5]
+        include/csetjmp [4:5]
+        include/csignal [4:5]
+        include/cstdarg [4:5]
+        include/cstdbool [4:5]
+        include/cstddef [4:5]
+        include/cstdint [4:5]
+        include/cstdio [4:5]
+        include/cstdlib [4:5]
+        include/cstring [4:5]
+        include/ctgmath [4:5]
+        include/ctime [4:5]
+        include/ctype.h [4:5]
+        include/cwchar [4:5]
+        include/cwctype [4:5]
+        include/deque [4:5]
+        include/errno.h [4:5]
+        include/exception [4:5]
+        include/execution [4:5]
+        include/experimental/__memory [4:5]
+        include/experimental/algorithm [4:5]
+        include/experimental/coroutine [4:5]
+        include/experimental/deque [4:5]
+        include/experimental/filesystem [4:5]
+        include/experimental/forward_list [4:5]
+        include/experimental/functional [4:5]
+        include/experimental/iterator [4:5]
+        include/experimental/list [4:5]
+        include/experimental/map [4:5]
+        include/experimental/memory_resource [4:5]
+        include/experimental/propagate_const [4:5]
+        include/experimental/regex [4:5]
+        include/experimental/set [4:5]
+        include/experimental/simd [4:5]
+        include/experimental/string [4:5]
+        include/experimental/type_traits [4:5]
+        include/experimental/unordered_map [4:5]
+        include/experimental/unordered_set [4:5]
+        include/experimental/utility [4:5]
+        include/experimental/vector [4:5]
+        include/ext/__hash [4:5]
+        include/ext/hash_map [4:5]
+        include/ext/hash_set [4:5]
+        include/filesystem [4:5]
+        include/float.h [4:5]
+        include/format [4:5]
+        include/forward_list [4:5]
+        include/fstream [4:5]
+        include/functional [4:5]
+        include/future [4:5]
+        include/initializer_list [4:5]
+        include/inttypes.h [4:5]
+        include/iomanip [4:5]
+        include/ios [4:5]
+        include/iosfwd [4:5]
+        include/iostream [4:5]
+        include/istream [4:5]
+        include/iterator [4:5]
+        include/latch [4:5]
+        include/limits [4:5]
+        include/limits.h [4:5]
+        include/list [4:5]
+        include/locale [4:5]
+        include/locale.h [4:5]
+        include/map [4:5]
+        include/math.h [4:5]
+        include/memory [4:5]
+        include/mutex [4:5]
+        include/new [4:5]
+        include/numbers [4:5]
+        include/numeric [4:5]
+        include/optional [4:5]
+        include/ostream [4:5]
+        include/queue [4:5]
+        include/random [4:5]
+        include/ranges [4:5]
+        include/ratio [4:5]
+        include/regex [4:5]
+        include/scoped_allocator [4:5]
+        include/semaphore [4:5]
+        include/set [4:5]
+        include/setjmp.h [4:5]
+        include/shared_mutex [4:5]
+        include/span [4:5]
+        include/sstream [4:5]
+        include/stack [4:5]
+        include/stdbool.h [4:5]
+        include/stddef.h [4:5]
+        include/stdexcept [4:5]
+        include/stdint.h [4:5]
+        include/stdio.h [4:5]
+        include/stdlib.h [4:5]
+        include/streambuf [4:5]
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+        include/string.h [4:5]
+        include/string_view [4:5]
+        include/strstream [4:5]
+        include/system_error [4:5]
+        include/tgmath.h [4:5]
+        include/thread [4:5]
+        include/tuple [4:5]
+        include/type_traits [4:5]
+        include/typeindex [4:5]
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+        include/valarray [4:5]
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+        include/vector [4:5]
+        include/version [4:5]
+        include/wchar.h [4:5]
+        include/wctype.h [4:5]
+        src/algorithm.cpp [3:4]
+        src/any.cpp [3:4]
+        src/atomic.cpp [3:4]
+        src/barrier.cpp [3:4]
+        src/bind.cpp [3:4]
+        src/charconv.cpp [3:4]
+        src/chrono.cpp [3:4]
+        src/condition_variable.cpp [3:4]
+        src/condition_variable_destructor.cpp [3:4]
+        src/debug.cpp [3:4]
+        src/exception.cpp [3:4]
+        src/experimental/memory_resource.cpp [3:4]
+        src/filesystem/directory_iterator.cpp [3:4]
+        src/filesystem/filesystem_common.h [3:4]
+        src/filesystem/operations.cpp [3:4]
+        src/filesystem/posix_compat.h [3:4]
+        src/format.cpp [3:4]
+        src/functional.cpp [3:4]
+        src/future.cpp [3:4]
+        src/hash.cpp [3:4]
+        src/include/apple_availability.h [3:4]
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+        src/include/refstring.h [3:4]
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+        src/ios.cpp [3:4]
+        src/ios.instantiations.cpp [3:4]
+        src/iostream.cpp [3:4]
+        src/locale.cpp [3:4]
+        src/memory.cpp [3:4]
+        src/mutex.cpp [3:4]
+        src/mutex_destructor.cpp [3:4]
+        src/new.cpp [3:4]
+        src/optional.cpp [3:4]
+        src/random.cpp [3:4]
+        src/random_shuffle.cpp [3:4]
+        src/regex.cpp [3:4]
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+        src/string.cpp [3:4]
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+        src/support/ibm/mbsnrtowcs.cpp [3:4]
+        src/support/ibm/wcsnrtombs.cpp [3:4]
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+        src/support/runtime/exception_fallback.ipp [4:5]
+        src/support/runtime/exception_glibcxx.ipp [4:5]
+        src/support/runtime/exception_libcxxabi.ipp [4:5]
+        src/support/runtime/exception_libcxxrt.ipp [4:5]
+        src/support/runtime/exception_msvc.ipp [4:5]
+        src/support/runtime/exception_pointer_cxxabi.ipp [4:5]
+        src/support/runtime/exception_pointer_glibcxx.ipp [4:5]
+        src/support/runtime/exception_pointer_msvc.ipp [4:5]
+        src/support/runtime/exception_pointer_unimplemented.ipp [4:5]
+        src/support/runtime/new_handler_fallback.ipp [4:5]
+        src/support/runtime/stdexcept_default.ipp [3:4]
+        src/support/runtime/stdexcept_vcruntime.ipp [3:4]
+        src/support/solaris/xlocale.cpp [3:4]
+        src/support/win32/locale_win32.cpp [4:5]
+        src/support/win32/support.cpp [4:5]
+        src/support/win32/thread_win32.cpp [4:5]
+        src/system_error.cpp [3:4]
+        src/thread.cpp [3:4]
+        src/typeinfo.cpp [3:4]
+        src/utility.cpp [3:4]
+        src/valarray.cpp [3:4]
+        src/variant.cpp [3:4]
+        src/vector.cpp [3:4]
+
+KEEP     Apache-2.0 WITH LLVM-exception 8494a9caed330d9a4f40e19cce7dc770
+BELONGS ya.make
+FILE_INCLUDE include/exception found in files: LICENSE.TXT at line 210
+    Note: matched license text is too long. Read it in the source files.
+    Scancode info:
+        Original SPDX id: LLVM-exception
+        Score           : 100.00
+        Match type      : TEXT
+        Links           : http://llvm.org/foundation/relicensing/LICENSE.txt, https://spdx.org/licenses/LLVM-exception
+    Files with this license:
+        LICENSE.TXT [208:222]
+
+KEEP     Apache-2.0 WITH LLVM-exception 86617d55e1d949711c543404d91f4cea
+BELONGS ya.make
+    License text:
+        // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+    Scancode info:
+        Original SPDX id: Apache-2.0
+        Score           : 100.00
+        Match type      : TAG
+        Links           : http://www.apache.org/licenses/, http://www.apache.org/licenses/LICENSE-2.0, https://spdx.org/licenses/Apache-2.0
+    Files with this license:
+        include/experimental/__config [6:6]
+    Scancode info:
+        Original SPDX id: LLVM-exception
+        Score           : 100.00
+        Match type      : TAG
+        Links           : http://llvm.org/foundation/relicensing/LICENSE.txt, https://spdx.org/licenses/LLVM-exception
+    Files with this license:
+        include/experimental/__config [6:6]
+
+KEEP     Apache-2.0           9ac77f65a898755c7eed97099caded94
+BELONGS ya.make
+FILE_INCLUDE import found in files: LICENSE.TXT at line 81
+FILE_INCLUDE include/any found in files: LICENSE.TXT at line 101, LICENSE.TXT at line 104, LICENSE.TXT at line 107, LICENSE.TXT at line 111, LICENSE.TXT at line 114, LICENSE.TXT at line 130, LICENSE.TXT at line 135, LICENSE.TXT at line 137, LICENSE.TXT at line 139, LICENSE.TXT at line 151, LICENSE.TXT at line 154, LICENSE.TXT at line 160, LICENSE.TXT at line 161, LICENSE.TXT at line 162, LICENSE.TXT at line 165, LICENSE.TXT at line 175, LICENSE.TXT at line 176, LICENSE.TXT at line 178, LICENSE.TXT at line 34, LICENSE.TXT at line 44, LICENSE.TXT at line 52, LICENSE.TXT at line 53, LICENSE.TXT at line 58, LICENSE.TXT at line 66, LICENSE.TXT at line 86, LICENSE.TXT at line 89, LICENSE.TXT at line 94, LICENSE.TXT at line 98
+FILE_INCLUDE include/format found in files: LICENSE.TXT at line 188
+FILE_INCLUDE include/version found in files: LICENSE.TXT at line 53
+    # any and version - just words, not file reference
+    Note: matched license text is too long. Read it in the source files.
+    Scancode info:
+        Original SPDX id: Apache-2.0
+        Score           : 100.00
+        Match type      : TEXT
+        Links           : http://www.apache.org/licenses/, http://www.apache.org/licenses/LICENSE-2.0, https://spdx.org/licenses/Apache-2.0
+    Files with this license:
+        LICENSE.TXT [5:205]
+
+KEEP     NCSA                 b160d8bd561da097b0edd40b062e1c84
+BELONGS ya.make
+FILE_INCLUDE include/any found in files: LICENSE.TXT at line 264
+FILE_INCLUDE include/experimental/list found in files: LICENSE.TXT at line 272, LICENSE.TXT at line 275
+FILE_INCLUDE include/list found in files: LICENSE.TXT at line 272, LICENSE.TXT at line 275
+    # any and list - just words, not file reference
+    Note: matched license text is too long. Read it in the source files.
+    Scancode info:
+        Original SPDX id: NCSA
+        Score           : 100.00
+        Match type      : TEXT
+        Links           : http://www.otm.illinois.edu/faculty/forms/opensource.asp, https://spdx.org/licenses/NCSA
+    Files with this license:
+        LICENSE.TXT [264:289]
+
+KEEP     BSD-2-Clause AND MIT b1ce5ac90fd7360272c132242b0d10e9
+BELONGS ya.make
+    License text:
+        2-clause BSD license instead of the MIT/UUIC license that the rest of libc++ is
+    Scancode info:
+        Original SPDX id: BSD-2-Clause
+        Score           : 100.00
+        Match type      : REFERENCE
+        Links           : http://opensource.org/licenses/bsd-license.php, http://www.opensource.org/licenses/BSD-2-Clause, https://spdx.org/licenses/BSD-2-Clause
+    Files with this license:
+        src/support/solaris/README [3:3]
+    Scancode info:
+        Original SPDX id: MIT
+        Score           : 75.00
+        Match type      : REFERENCE
+        Links           : http://opensource.org/licenses/mit-license.php, https://spdx.org/licenses/MIT
+    Files with this license:
+        src/support/solaris/README [3:3]
+
+KEEP     Apache-2.0 WITH LLVM-exception b4f32daeb289687c0be6afeacb7df231
+BELONGS ya.make
+    License text:
+        // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+        // See https://llvm.org/LICENSE.txt for license information.
+    Scancode info:
+        Original SPDX id: Apache-2.0
+        Score           : 100.00
+        Match type      : NOTICE
+        Links           : http://www.apache.org/licenses/, http://www.apache.org/licenses/LICENSE-2.0, https://spdx.org/licenses/Apache-2.0
+    Files with this license:
+        include/experimental/__config [4:5]
+    Scancode info:
+        Original SPDX id: LLVM-exception
+        Score           : 100.00
+        Match type      : NOTICE
+        Links           : http://llvm.org/foundation/relicensing/LICENSE.txt, https://spdx.org/licenses/LLVM-exception
+    Files with this license:
+        include/experimental/__config [4:5]
+
+KEEP     Apache-2.0 WITH LLVM-exception b7566a1930e050e1090162bf1d543650
+BELONGS ya.make
+    License text:
+        // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+    Scancode info:
+        Original SPDX id: Apache-2.0
+        Score           : 100.00
+        Match type      : TAG
+        Links           : http://www.apache.org/licenses/, http://www.apache.org/licenses/LICENSE-2.0, https://spdx.org/licenses/Apache-2.0
+    Files with this license:
+        include/__algorithm/adjacent_find.h [6:6]
+        include/__algorithm/all_of.h [6:6]
+        include/__algorithm/any_of.h [6:6]
+        include/__algorithm/binary_search.h [5:5]
+        include/__algorithm/clamp.h [5:5]
+        include/__algorithm/comp.h [5:5]
+        include/__algorithm/comp_ref_type.h [5:5]
+        include/__algorithm/copy.h [5:5]
+        include/__algorithm/copy_backward.h [5:5]
+        include/__algorithm/copy_if.h [5:5]
+        include/__algorithm/copy_n.h [5:5]
+        include/__algorithm/count.h [6:6]
+        include/__algorithm/count_if.h [6:6]
+        include/__algorithm/equal.h [6:6]
+        include/__algorithm/equal_range.h [5:5]
+        include/__algorithm/fill.h [5:5]
+        include/__algorithm/fill_n.h [5:5]
+        include/__algorithm/find.h [6:6]
+        include/__algorithm/find_end.h [6:6]
+        include/__algorithm/find_first_of.h [6:6]
+        include/__algorithm/find_if.h [6:6]
+        include/__algorithm/find_if_not.h [6:6]
+        include/__algorithm/for_each.h [6:6]
+        include/__algorithm/for_each_n.h [6:6]
+        include/__algorithm/generate.h [5:5]
+        include/__algorithm/generate_n.h [5:5]
+        include/__algorithm/half_positive.h [5:5]
+        include/__algorithm/includes.h [5:5]
+        include/__algorithm/inplace_merge.h [5:5]
+        include/__algorithm/is_heap.h [5:5]
+        include/__algorithm/is_heap_until.h [5:5]
+        include/__algorithm/is_partitioned.h [5:5]
+        include/__algorithm/is_permutation.h [6:6]
+        include/__algorithm/is_sorted.h [5:5]
+        include/__algorithm/is_sorted_until.h [5:5]
+        include/__algorithm/iter_swap.h [5:5]
+        include/__algorithm/lexicographical_compare.h [5:5]
+        include/__algorithm/lower_bound.h [5:5]
+        include/__algorithm/make_heap.h [5:5]
+        include/__algorithm/max.h [5:5]
+        include/__algorithm/max_element.h [5:5]
+        include/__algorithm/merge.h [5:5]
+        include/__algorithm/min.h [5:5]
+        include/__algorithm/min_element.h [5:5]
+        include/__algorithm/minmax.h [5:5]
+        include/__algorithm/minmax_element.h [5:5]
+        include/__algorithm/mismatch.h [6:6]
+        include/__algorithm/move.h [5:5]
+        include/__algorithm/move_backward.h [5:5]
+        include/__algorithm/next_permutation.h [5:5]
+        include/__algorithm/none_of.h [6:6]
+        include/__algorithm/nth_element.h [5:5]
+        include/__algorithm/partial_sort.h [5:5]
+        include/__algorithm/partial_sort_copy.h [5:5]
+        include/__algorithm/partition.h [5:5]
+        include/__algorithm/partition_copy.h [5:5]
+        include/__algorithm/partition_point.h [5:5]
+        include/__algorithm/pop_heap.h [5:5]
+        include/__algorithm/prev_permutation.h [5:5]
+        include/__algorithm/push_heap.h [5:5]
+        include/__algorithm/remove.h [5:5]
+        include/__algorithm/remove_copy.h [5:5]
+        include/__algorithm/remove_copy_if.h [5:5]
+        include/__algorithm/remove_if.h [5:5]
+        include/__algorithm/replace.h [5:5]
+        include/__algorithm/replace_copy.h [5:5]
+        include/__algorithm/replace_copy_if.h [5:5]
+        include/__algorithm/replace_if.h [5:5]
+        include/__algorithm/reverse.h [5:5]
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+        include/__algorithm/rotate.h [5:5]
+        include/__algorithm/rotate_copy.h [5:5]
+        include/__algorithm/sample.h [5:5]
+        include/__algorithm/search.h [6:6]
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+        include/__algorithm/set_difference.h [5:5]
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+        include/__algorithm/set_symmetric_difference.h [5:5]
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+        include/__algorithm/shift_left.h [5:5]
+        include/__algorithm/shift_right.h [5:5]
+        include/__algorithm/shuffle.h [5:5]
+        include/__algorithm/sift_down.h [5:5]
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+        include/__algorithm/sort_heap.h [5:5]
+        include/__algorithm/stable_partition.h [5:5]
+        include/__algorithm/stable_sort.h [5:5]
+        include/__algorithm/swap_ranges.h [5:5]
+        include/__algorithm/transform.h [5:5]
+        include/__algorithm/unique.h [5:5]
+        include/__algorithm/unique_copy.h [5:5]
+        include/__algorithm/unwrap_iter.h [5:5]
+        include/__algorithm/upper_bound.h [5:5]
+        include/__availability [6:6]
+        include/__bit/bit_cast.h [6:6]
+        include/__bit_reference [6:6]
+        include/__bits [6:6]
+        include/__bsd_locale_defaults.h [6:6]
+        include/__bsd_locale_fallbacks.h [6:6]
+        include/__charconv/chars_format.h [6:6]
+        include/__charconv/from_chars_result.h [6:6]
+        include/__charconv/to_chars_result.h [6:6]
+        include/__compare/common_comparison_category.h [5:5]
+        include/__compare/compare_three_way_result.h [5:5]
+        include/__compare/ordering.h [5:5]
+        include/__compare/synth_three_way.h [5:5]
+        include/__compare/three_way_comparable.h [5:5]
+        include/__concepts/arithmetic.h [5:5]
+        include/__concepts/assignable.h [5:5]
+        include/__concepts/boolean_testable.h [5:5]
+        include/__concepts/class_or_enum.h [5:5]
+        include/__concepts/common_reference_with.h [5:5]
+        include/__concepts/common_with.h [5:5]
+        include/__concepts/constructible.h [5:5]
+        include/__concepts/convertible_to.h [5:5]
+        include/__concepts/copyable.h [5:5]
+        include/__concepts/derived_from.h [5:5]
+        include/__concepts/destructible.h [5:5]
+        include/__concepts/different_from.h [5:5]
+        include/__concepts/equality_comparable.h [5:5]
+        include/__concepts/invocable.h [5:5]
+        include/__concepts/movable.h [5:5]
+        include/__concepts/predicate.h [5:5]
+        include/__concepts/regular.h [5:5]
+        include/__concepts/relation.h [5:5]
+        include/__concepts/same_as.h [5:5]
+        include/__concepts/semiregular.h [5:5]
+        include/__concepts/swappable.h [5:5]
+        include/__concepts/totally_ordered.h [5:5]
+        include/__config [6:6]
+        include/__config_site.in [5:5]
+        include/__debug [6:6]
+        include/__errc [6:6]
+        include/__format/format_arg.h [6:6]
+        include/__format/format_args.h [6:6]
+        include/__format/format_context.h [6:6]
+        include/__format/format_error.h [6:6]
+        include/__format/format_fwd.h [6:6]
+        include/__format/format_parse_context.h [6:6]
+        include/__format/format_string.h [6:6]
+        include/__format/formatter.h [6:6]
+        include/__format/parser_std_format_spec.h [6:6]
+        include/__function_like.h [6:6]
+        include/__functional/binary_function.h [6:6]
+        include/__functional/binary_negate.h [6:6]
+        include/__functional/bind.h [6:6]
+        include/__functional/bind_back.h [6:6]
+        include/__functional/bind_front.h [6:6]
+        include/__functional/binder1st.h [6:6]
+        include/__functional/binder2nd.h [6:6]
+        include/__functional/compose.h [6:6]
+        include/__functional/default_searcher.h [6:6]
+        include/__functional/function.h [6:6]
+        include/__functional/hash.h [5:5]
+        include/__functional/identity.h [6:6]
+        include/__functional/invoke.h [6:6]
+        include/__functional/is_transparent.h [6:6]
+        include/__functional/mem_fn.h [6:6]
+        include/__functional/mem_fun_ref.h [6:6]
+        include/__functional/not_fn.h [6:6]
+        include/__functional/operations.h [6:6]
+        include/__functional/perfect_forward.h [6:6]
+        include/__functional/pointer_to_binary_function.h [6:6]
+        include/__functional/pointer_to_unary_function.h [6:6]
+        include/__functional/ranges_operations.h [6:6]
+        include/__functional/reference_wrapper.h [6:6]
+        include/__functional/unary_function.h [5:5]
+        include/__functional/unary_negate.h [6:6]
+        include/__functional/unwrap_ref.h [5:5]
+        include/__functional/weak_result_type.h [6:6]
+        include/__functional_base [6:6]
+        include/__hash_table [6:6]
+        include/__iterator/access.h [6:6]
+        include/__iterator/advance.h [6:6]
+        include/__iterator/back_insert_iterator.h [6:6]
+        include/__iterator/common_iterator.h [6:6]
+        include/__iterator/concepts.h [6:6]
+        include/__iterator/counted_iterator.h [6:6]
+        include/__iterator/data.h [6:6]
+        include/__iterator/default_sentinel.h [6:6]
+        include/__iterator/distance.h [6:6]
+        include/__iterator/empty.h [6:6]
+        include/__iterator/erase_if_container.h [6:6]
+        include/__iterator/front_insert_iterator.h [6:6]
+        include/__iterator/incrementable_traits.h [6:6]
+        include/__iterator/insert_iterator.h [6:6]
+        include/__iterator/istream_iterator.h [6:6]
+        include/__iterator/istreambuf_iterator.h [6:6]
+        include/__iterator/iter_move.h [6:6]
+        include/__iterator/iter_swap.h [6:6]
+        include/__iterator/iterator.h [6:6]
+        include/__iterator/iterator_traits.h [6:6]
+        include/__iterator/move_iterator.h [6:6]
+        include/__iterator/next.h [6:6]
+        include/__iterator/ostream_iterator.h [6:6]
+        include/__iterator/ostreambuf_iterator.h [6:6]
+        include/__iterator/prev.h [6:6]
+        include/__iterator/projected.h [6:6]
+        include/__iterator/readable_traits.h [6:6]
+        include/__iterator/reverse_access.h [6:6]
+        include/__iterator/reverse_iterator.h [6:6]
+        include/__iterator/size.h [6:6]
+        include/__iterator/unreachable_sentinel.h [6:6]
+        include/__iterator/wrap_iter.h [6:6]
+        include/__locale [6:6]
+        include/__memory/addressof.h [6:6]
+        include/__memory/allocation_guard.h [6:6]
+        include/__memory/allocator.h [6:6]
+        include/__memory/allocator_arg_t.h [6:6]
+        include/__memory/allocator_traits.h [6:6]
+        include/__memory/auto_ptr.h [6:6]
+        include/__memory/compressed_pair.h [6:6]
+        include/__memory/construct_at.h [6:6]
+        include/__memory/pointer_safety.h [6:6]
+        include/__memory/pointer_traits.h [6:6]
+        include/__memory/raw_storage_iterator.h [6:6]
+        include/__memory/shared_ptr.h [6:6]
+        include/__memory/temporary_buffer.h [6:6]
+        include/__memory/uninitialized_algorithms.h [6:6]
+        include/__memory/unique_ptr.h [6:6]
+        include/__memory/uses_allocator.h [6:6]
+        include/__mutex_base [6:6]
+        include/__node_handle [6:6]
+        include/__nullptr [6:6]
+        include/__random/uniform_int_distribution.h [5:5]
+        include/__ranges/access.h [6:6]
+        include/__ranges/all.h [6:6]
+        include/__ranges/common_view.h [6:6]
+        include/__ranges/concepts.h [6:6]
+        include/__ranges/copyable_box.h [6:6]
+        include/__ranges/counted.h [6:6]
+        include/__ranges/dangling.h [6:6]
+        include/__ranges/data.h [6:6]
+        include/__ranges/drop_view.h [6:6]
+        include/__ranges/empty.h [6:6]
+        include/__ranges/empty_view.h [6:6]
+        include/__ranges/enable_borrowed_range.h [6:6]
+        include/__ranges/enable_view.h [6:6]
+        include/__ranges/iota_view.h [6:6]
+        include/__ranges/join_view.h [6:6]
+        include/__ranges/non_propagating_cache.h [6:6]
+        include/__ranges/range_adaptor.h [6:6]
+        include/__ranges/ref_view.h [6:6]
+        include/__ranges/reverse_view.h [6:6]
+        include/__ranges/single_view.h [6:6]
+        include/__ranges/size.h [6:6]
+        include/__ranges/subrange.h [6:6]
+        include/__ranges/take_view.h [6:6]
+        include/__ranges/transform_view.h [6:6]
+        include/__ranges/view_interface.h [6:6]
+        include/__std_stream [6:6]
+        include/__string [6:6]
+        include/__support/android/locale_bionic.h [6:6]
+        include/__support/fuchsia/xlocale.h [6:6]
+        include/__support/ibm/gettod_zos.h [6:6]
+        include/__support/ibm/limits.h [6:6]
+        include/__support/ibm/locale_mgmt_zos.h [6:6]
+        include/__support/ibm/nanosleep.h [6:6]
+        include/__support/ibm/support.h [6:6]
+        include/__support/ibm/xlocale.h [6:6]
+        include/__support/musl/xlocale.h [6:6]
+        include/__support/newlib/xlocale.h [5:5]
+        include/__support/openbsd/xlocale.h [6:6]
+        include/__support/solaris/floatingpoint.h [5:5]
+        include/__support/solaris/wchar.h [5:5]
+        include/__support/solaris/xlocale.h [5:5]
+        include/__support/win32/limits_msvc_win32.h [6:6]
+        include/__support/win32/locale_win32.h [6:6]
+        include/__support/xlocale/__nop_locale_mgmt.h [6:6]
+        include/__support/xlocale/__posix_l_fallback.h [6:6]
+        include/__support/xlocale/__strtonum_fallback.h [6:6]
+        include/__threading_support [6:6]
+        include/__tree [6:6]
+        include/__tuple [6:6]
+        include/__undef_macros [6:6]
+        include/__utility/as_const.h [5:5]
+        include/__utility/cmp.h [5:5]
+        include/__utility/decay_copy.h [6:6]
+        include/__utility/declval.h [5:5]
+        include/__utility/exchange.h [5:5]
+        include/__utility/forward.h [6:6]
+        include/__utility/in_place.h [5:5]
+        include/__utility/integer_sequence.h [5:5]
+        include/__utility/move.h [6:6]
+        include/__utility/pair.h [5:5]
+        include/__utility/piecewise_construct.h [5:5]
+        include/__utility/rel_ops.h [5:5]
+        include/__utility/swap.h [5:5]
+        include/__utility/to_underlying.h [6:6]
+        include/__variant/monostate.h [6:6]
+        include/algorithm [6:6]
+        include/any [6:6]
+        include/array [6:6]
+        include/atomic [6:6]
+        include/barrier [6:6]
+        include/bit [6:6]
+        include/bitset [6:6]
+        include/cassert [6:6]
+        include/ccomplex [6:6]
+        include/cctype [6:6]
+        include/cerrno [6:6]
+        include/cfenv [6:6]
+        include/cfloat [6:6]
+        include/charconv [6:6]
+        include/chrono [6:6]
+        include/cinttypes [6:6]
+        include/ciso646 [6:6]
+        include/climits [6:6]
+        include/clocale [6:6]
+        include/cmath [6:6]
+        include/codecvt [6:6]
+        include/compare [6:6]
+        include/complex [6:6]
+        include/complex.h [6:6]
+        include/concepts [6:6]
+        include/condition_variable [6:6]
+        include/csetjmp [6:6]
+        include/csignal [6:6]
+        include/cstdarg [6:6]
+        include/cstdbool [6:6]
+        include/cstddef [6:6]
+        include/cstdint [6:6]
+        include/cstdio [6:6]
+        include/cstdlib [6:6]
+        include/cstring [6:6]
+        include/ctgmath [6:6]
+        include/ctime [6:6]
+        include/ctype.h [6:6]
+        include/cwchar [6:6]
+        include/cwctype [6:6]
+        include/deque [6:6]
+        include/errno.h [6:6]
+        include/exception [6:6]
+        include/execution [6:6]
+        include/experimental/__memory [6:6]
+        include/experimental/algorithm [6:6]
+        include/experimental/coroutine [6:6]
+        include/experimental/deque [6:6]
+        include/experimental/filesystem [6:6]
+        include/experimental/forward_list [6:6]
+        include/experimental/functional [6:6]
+        include/experimental/iterator [6:6]
+        include/experimental/list [6:6]
+        include/experimental/map [6:6]
+        include/experimental/memory_resource [6:6]
+        include/experimental/propagate_const [6:6]
+        include/experimental/regex [6:6]
+        include/experimental/set [6:6]
+        include/experimental/simd [6:6]
+        include/experimental/string [6:6]
+        include/experimental/type_traits [6:6]
+        include/experimental/unordered_map [6:6]
+        include/experimental/unordered_set [6:6]
+        include/experimental/utility [6:6]
+        include/experimental/vector [6:6]
+        include/ext/__hash [6:6]
+        include/ext/hash_map [6:6]
+        include/ext/hash_set [6:6]
+        include/filesystem [6:6]
+        include/float.h [6:6]
+        include/format [6:6]
+        include/forward_list [6:6]
+        include/fstream [6:6]
+        include/functional [6:6]
+        include/future [6:6]
+        include/initializer_list [6:6]
+        include/inttypes.h [6:6]
+        include/iomanip [6:6]
+        include/ios [6:6]
+        include/iosfwd [6:6]
+        include/iostream [6:6]
+        include/istream [6:6]
+        include/iterator [6:6]
+        include/latch [6:6]
+        include/limits [6:6]
+        include/limits.h [6:6]
+        include/list [6:6]
+        include/locale [6:6]
+        include/locale.h [6:6]
+        include/map [6:6]
+        include/math.h [6:6]
+        include/memory [6:6]
+        include/mutex [6:6]
+        include/new [6:6]
+        include/numbers [6:6]
+        include/numeric [6:6]
+        include/optional [6:6]
+        include/ostream [6:6]
+        include/queue [6:6]
+        include/random [6:6]
+        include/ranges [6:6]
+        include/ratio [6:6]
+        include/regex [6:6]
+        include/scoped_allocator [6:6]
+        include/semaphore [6:6]
+        include/set [6:6]
+        include/setjmp.h [6:6]
+        include/shared_mutex [6:6]
+        include/span [6:6]
+        include/sstream [6:6]
+        include/stack [6:6]
+        include/stdbool.h [6:6]
+        include/stddef.h [6:6]
+        include/stdexcept [6:6]
+        include/stdint.h [6:6]
+        include/stdio.h [6:6]
+        include/stdlib.h [6:6]
+        include/streambuf [6:6]
+        include/string [6:6]
+        include/string.h [6:6]
+        include/string_view [6:6]
+        include/strstream [6:6]
+        include/system_error [6:6]
+        include/tgmath.h [6:6]
+        include/thread [6:6]
+        include/tuple [6:6]
+        include/type_traits [6:6]
+        include/typeindex [6:6]
+        include/typeinfo [6:6]
+        include/unordered_map [6:6]
+        include/unordered_set [6:6]
+        include/utility [6:6]
+        include/valarray [6:6]
+        include/variant [6:6]
+        include/vector [6:6]
+        include/version [6:6]
+        include/wchar.h [6:6]
+        include/wctype.h [6:6]
+        src/algorithm.cpp [5:5]
+        src/any.cpp [5:5]
+        src/atomic.cpp [5:5]
+        src/barrier.cpp [5:5]
+        src/bind.cpp [5:5]
+        src/charconv.cpp [5:5]
+        src/chrono.cpp [5:5]
+        src/condition_variable.cpp [5:5]
+        src/condition_variable_destructor.cpp [5:5]
+        src/debug.cpp [5:5]
+        src/exception.cpp [5:5]
+        src/experimental/memory_resource.cpp [5:5]
+        src/filesystem/directory_iterator.cpp [5:5]
+        src/filesystem/filesystem_common.h [5:5]
+        src/filesystem/operations.cpp [5:5]
+        src/filesystem/posix_compat.h [5:5]
+        src/format.cpp [5:5]
+        src/functional.cpp [5:5]
+        src/future.cpp [5:5]
+        src/hash.cpp [5:5]
+        src/include/apple_availability.h [5:5]
+        src/include/atomic_support.h [5:5]
+        src/include/config_elast.h [5:5]
+        src/include/refstring.h [5:5]
+        src/include/sso_allocator.h [6:6]
+        src/ios.cpp [5:5]
+        src/ios.instantiations.cpp [5:5]
+        src/iostream.cpp [5:5]
+        src/locale.cpp [5:5]
+        src/memory.cpp [5:5]
+        src/mutex.cpp [5:5]
+        src/mutex_destructor.cpp [5:5]
+        src/new.cpp [5:5]
+        src/optional.cpp [5:5]
+        src/random.cpp [5:5]
+        src/random_shuffle.cpp [5:5]
+        src/regex.cpp [5:5]
+        src/shared_mutex.cpp [5:5]
+        src/stdexcept.cpp [5:5]
+        src/string.cpp [5:5]
+        src/strstream.cpp [5:5]
+        src/support/ibm/mbsnrtowcs.cpp [5:5]
+        src/support/ibm/wcsnrtombs.cpp [5:5]
+        src/support/ibm/xlocale_zos.cpp [5:5]
+        src/support/runtime/exception_fallback.ipp [6:6]
+        src/support/runtime/exception_glibcxx.ipp [6:6]
+        src/support/runtime/exception_libcxxabi.ipp [6:6]
+        src/support/runtime/exception_libcxxrt.ipp [6:6]
+        src/support/runtime/exception_msvc.ipp [6:6]
+        src/support/runtime/exception_pointer_cxxabi.ipp [6:6]
+        src/support/runtime/exception_pointer_glibcxx.ipp [6:6]
+        src/support/runtime/exception_pointer_msvc.ipp [6:6]
+        src/support/runtime/exception_pointer_unimplemented.ipp [6:6]
+        src/support/runtime/new_handler_fallback.ipp [6:6]
+        src/support/runtime/stdexcept_default.ipp [5:5]
+        src/support/runtime/stdexcept_vcruntime.ipp [5:5]
+        src/support/solaris/xlocale.cpp [5:5]
+        src/support/win32/locale_win32.cpp [6:6]
+        src/support/win32/support.cpp [6:6]
+        src/support/win32/thread_win32.cpp [6:6]
+        src/system_error.cpp [5:5]
+        src/thread.cpp [5:5]
+        src/typeinfo.cpp [5:5]
+        src/utility.cpp [5:5]
+        src/valarray.cpp [5:5]
+        src/variant.cpp [5:5]
+        src/vector.cpp [5:5]
+    Scancode info:
+        Original SPDX id: LLVM-exception
+        Score           : 100.00
+        Match type      : TAG
+        Links           : http://llvm.org/foundation/relicensing/LICENSE.txt, https://spdx.org/licenses/LLVM-exception
+    Files with this license:
+        include/__algorithm/adjacent_find.h [6:6]
+        include/__algorithm/all_of.h [6:6]
+        include/__algorithm/any_of.h [6:6]
+        include/__algorithm/binary_search.h [5:5]
+        include/__algorithm/clamp.h [5:5]
+        include/__algorithm/comp.h [5:5]
+        include/__algorithm/comp_ref_type.h [5:5]
+        include/__algorithm/copy.h [5:5]
+        include/__algorithm/copy_backward.h [5:5]
+        include/__algorithm/copy_if.h [5:5]
+        include/__algorithm/copy_n.h [5:5]
+        include/__algorithm/count.h [6:6]
+        include/__algorithm/count_if.h [6:6]
+        include/__algorithm/equal.h [6:6]
+        include/__algorithm/equal_range.h [5:5]
+        include/__algorithm/fill.h [5:5]
+        include/__algorithm/fill_n.h [5:5]
+        include/__algorithm/find.h [6:6]
+        include/__algorithm/find_end.h [6:6]
+        include/__algorithm/find_first_of.h [6:6]
+        include/__algorithm/find_if.h [6:6]
+        include/__algorithm/find_if_not.h [6:6]
+        include/__algorithm/for_each.h [6:6]
+        include/__algorithm/for_each_n.h [6:6]
+        include/__algorithm/generate.h [5:5]
+        include/__algorithm/generate_n.h [5:5]
+        include/__algorithm/half_positive.h [5:5]
+        include/__algorithm/includes.h [5:5]
+        include/__algorithm/inplace_merge.h [5:5]
+        include/__algorithm/is_heap.h [5:5]
+        include/__algorithm/is_heap_until.h [5:5]
+        include/__algorithm/is_partitioned.h [5:5]
+        include/__algorithm/is_permutation.h [6:6]
+        include/__algorithm/is_sorted.h [5:5]
+        include/__algorithm/is_sorted_until.h [5:5]
+        include/__algorithm/iter_swap.h [5:5]
+        include/__algorithm/lexicographical_compare.h [5:5]
+        include/__algorithm/lower_bound.h [5:5]
+        include/__algorithm/make_heap.h [5:5]
+        include/__algorithm/max.h [5:5]
+        include/__algorithm/max_element.h [5:5]
+        include/__algorithm/merge.h [5:5]
+        include/__algorithm/min.h [5:5]
+        include/__algorithm/min_element.h [5:5]
+        include/__algorithm/minmax.h [5:5]
+        include/__algorithm/minmax_element.h [5:5]
+        include/__algorithm/mismatch.h [6:6]
+        include/__algorithm/move.h [5:5]
+        include/__algorithm/move_backward.h [5:5]
+        include/__algorithm/next_permutation.h [5:5]
+        include/__algorithm/none_of.h [6:6]
+        include/__algorithm/nth_element.h [5:5]
+        include/__algorithm/partial_sort.h [5:5]
+        include/__algorithm/partial_sort_copy.h [5:5]
+        include/__algorithm/partition.h [5:5]
+        include/__algorithm/partition_copy.h [5:5]
+        include/__algorithm/partition_point.h [5:5]
+        include/__algorithm/pop_heap.h [5:5]
+        include/__algorithm/prev_permutation.h [5:5]
+        include/__algorithm/push_heap.h [5:5]
+        include/__algorithm/remove.h [5:5]
+        include/__algorithm/remove_copy.h [5:5]
+        include/__algorithm/remove_copy_if.h [5:5]
+        include/__algorithm/remove_if.h [5:5]
+        include/__algorithm/replace.h [5:5]
+        include/__algorithm/replace_copy.h [5:5]
+        include/__algorithm/replace_copy_if.h [5:5]
+        include/__algorithm/replace_if.h [5:5]
+        include/__algorithm/reverse.h [5:5]
+        include/__algorithm/reverse_copy.h [5:5]
+        include/__algorithm/rotate.h [5:5]
+        include/__algorithm/rotate_copy.h [5:5]
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+
+KEEP     Apache-2.0 WITH LLVM-exception c1e6c6536fcc444f916047679115c618
+BELONGS ya.make
+    License text:
+         * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+    Scancode info:
+        Original SPDX id: Apache-2.0
+        Score           : 100.00
+        Match type      : TAG
+        Links           : http://www.apache.org/licenses/, http://www.apache.org/licenses/LICENSE-2.0, https://spdx.org/licenses/Apache-2.0
+    Files with this license:
+        src/filesystem/int128_builtins.cpp [5:5]
+    Scancode info:
+        Original SPDX id: LLVM-exception
+        Score           : 100.00
+        Match type      : TAG
+        Links           : http://llvm.org/foundation/relicensing/LICENSE.txt, https://spdx.org/licenses/LLVM-exception
+    Files with this license:
+        src/filesystem/int128_builtins.cpp [5:5]
+
+KEEP     NCSA                 c26d0b72f92421989c4471ae0acbc943
+BELONGS ya.make
+    License text:
+        University of Illinois/NCSA
+        Open Source License
+    Scancode info:
+        Original SPDX id: NCSA
+        Score           : 100.00
+        Match type      : REFERENCE
+        Links           : http://www.otm.illinois.edu/faculty/forms/opensource.asp, https://spdx.org/licenses/NCSA
+    Files with this license:
+        LICENSE.TXT [249:250]
+
+SKIP     LicenseRef-scancode-unknown-license-reference d4fd839c20b32e384ccf02a801e876d1
+BELONGS ya.make
+    # part of bsd-2-clause text
+    License text:
+        distributed under.
+    Scancode info:
+        Original SPDX id: LicenseRef-scancode-unknown-license-reference
+        Score           : 11.00
+        Match type      : INTRO
+        Links           : https://github.com/nexB/scancode-toolkit/tree/develop/src/licensedcode/data/licenses/unknown-license-reference.LICENSE
+    Files with this license:
+        src/support/solaris/README [4:4]
+
+KEEP     Apache-2.0 WITH LLVM-exception df18889e552d44a4679aff552267f802
+BELONGS ya.make
+    License text:
+        The LLVM Project is under the Apache License v2.0 with LLVM Exceptions:
+    Scancode info:
+        Original SPDX id: Apache-2.0
+        Score           : 100.00
+        Match type      : NOTICE
+        Links           : http://www.apache.org/licenses/, http://www.apache.org/licenses/LICENSE-2.0, https://spdx.org/licenses/Apache-2.0
+    Files with this license:
+        LICENSE.TXT [2:2]
+    Scancode info:
+        Original SPDX id: LLVM-exception
+        Score           : 100.00
+        Match type      : NOTICE
+        Links           : http://llvm.org/foundation/relicensing/LICENSE.txt, https://spdx.org/licenses/LLVM-exception
+    Files with this license:
+        LICENSE.TXT [2:2]
+
+KEEP     BSD-2-Clause         f59cebb43ee786218189ac014af76fbb
+BELONGS ya.make
+FILE_INCLUDE include/experimental/list found in files: src/support/solaris/mbsnrtowcs.inc at line 13, src/support/solaris/mbsnrtowcs.inc at line 15, src/support/solaris/wcsnrtombs.inc at line 10, src/support/solaris/wcsnrtombs.inc at line 8
+FILE_INCLUDE include/list found in files: src/support/solaris/mbsnrtowcs.inc at line 13, src/support/solaris/mbsnrtowcs.inc at line 15, src/support/solaris/wcsnrtombs.inc at line 10, src/support/solaris/wcsnrtombs.inc at line 8
+    # list - just word, not file reference
+    Note: matched license text is too long. Read it in the source files.
+    Scancode info:
+        Original SPDX id: BSD-2-Clause
+        Score           : 100.00
+        Match type      : TEXT
+        Links           : http://opensource.org/licenses/bsd-license.php, http://www.opensource.org/licenses/BSD-2-Clause, https://spdx.org/licenses/BSD-2-Clause
+    Files with this license:
+        src/support/solaris/mbsnrtowcs.inc [9:28]
+        src/support/solaris/wcsnrtombs.inc [4:23]
diff --git a/contrib/libs/cxxsupp/libcxx/.yandex_meta/licenses.list.txt b/contrib/libs/cxxsupp/libcxx/.yandex_meta/licenses.list.txt
new file mode 100644
index 00000000000..b13eb77e463
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/.yandex_meta/licenses.list.txt
@@ -0,0 +1,5409 @@
+====================Apache-2.0====================
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+    TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+    1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
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+
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+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
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+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
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+
+      "Work" shall mean the work of authorship, whether in Source or
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+      copyright notice that is included in or attached to the work
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+
+      "Derivative Works" shall mean any work, whether in Source or Object
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+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
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+      "Contributor" shall mean Licensor and any individual or Legal Entity
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+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
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+
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+      names, trademarks, service marks, or product names of the Licensor,
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+
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+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
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+       http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+
+
+====================Apache-2.0 WITH LLVM-exception====================
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+
+
+====================Apache-2.0 WITH LLVM-exception====================
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+
+====================Apache-2.0 WITH LLVM-exception====================
+---- LLVM Exceptions to the Apache 2.0 License ----
+
+As an exception, if, as a result of your compiling your source code, portions
+of this Software are embedded into an Object form of such source code, you
+may redistribute such embedded portions in such Object form without complying
+with the conditions of Sections 4(a), 4(b) and 4(d) of the License.
+
+In addition, if you combine or link compiled forms of this Software with
+software that is licensed under the GPLv2 ("Combined Software") and if a
+court of competent jurisdiction determines that the patent provision (Section
+3), the indemnity provision (Section 9) or other Section of the License
+conflicts with the conditions of the GPLv2, you may retroactively and
+prospectively choose to deem waived or otherwise exclude such Section(s) of
+the License, but only in their entirety and only with respect to the Combined
+Software.
+
+
+====================Apache-2.0 WITH LLVM-exception====================
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+
+
+====================Apache-2.0 WITH LLVM-exception====================
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+
+====================Apache-2.0 WITH LLVM-exception====================
+The LLVM Project is under the Apache License v2.0 with LLVM Exceptions:
+
+
+====================BSD-2-Clause====================
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+
+
+====================BSD-2-Clause AND MIT====================
+2-clause BSD license instead of the MIT/UUIC license that the rest of libc++ is
+
+
+====================COPYRIGHT====================
+ * FreeBSD libc.  These are covered by the following copyright:
+ *
+ * Copyright (c) 2002-2004 Tim J. Robbins.
+
+
+====================COPYRIGHT====================
+Copyright (c) 2009-2014 by the contributors listed in CREDITS.TXT
+
+
+====================COPYRIGHT====================
+Copyright (c) 2009-2019 by the contributors listed in CREDITS.TXT
+
+
+====================File: CREDITS.TXT====================
+This file is a partial list of people who have contributed to the LLVM/libc++
+project.  If you have contributed a patch or made some other contribution to
+LLVM/libc++, please submit a patch to this file to add yourself, and it will be
+done!
+
+The list is sorted by surname and formatted to allow easy grepping and
+beautification by scripts.  The fields are: name (N), email (E), web-address
+(W), PGP key ID and fingerprint (P), description (D), and snail-mail address
+(S).
+
+N: Saleem Abdulrasool
+E: compnerd@compnerd.org
+D: Minor patches and Linux fixes.
+
+N: Dan Albert
+E: danalbert@google.com
+D: Android support and test runner improvements.
+
+N: Dimitry Andric
+E: dimitry@andric.com
+D: Visibility fixes, minor FreeBSD portability patches.
+
+N: Holger Arnold
+E: holgerar@gmail.com
+D: Minor fix.
+
+N: David Chisnall
+E: theraven at theravensnest dot org
+D: FreeBSD and Solaris ports, libcxxrt support, some atomics work.
+
+N: Marshall Clow
+E: mclow.lists@gmail.com
+E: marshall@idio.com
+D: C++14 support, patches and bug fixes.
+
+N: Jonathan B Coe
+E: jbcoe@me.com
+D: Implementation of propagate_const.
+
+N: Matthew Dempsky
+E: matthew@dempsky.org
+D: Minor patches and bug fixes.
+
+N: Christopher Di Bella
+E: cjdb@google.com
+E: cjdb.ns@gmail.com
+D: Library concepts.
+
+N: Glen Joseph Fernandes
+E: glenjofe@gmail.com
+D: Implementation of to_address.
+
+N: Eric Fiselier
+E: eric@efcs.ca
+D: LFTS support, patches and bug fixes.
+
+N: Bill Fisher
+E: william.w.fisher@gmail.com
+D: Regex bug fixes.
+
+N: Google Inc.
+D: Copyright owner and contributor of the CityHash algorithm
+
+N: Howard Hinnant
+E: hhinnant@apple.com
+D: Architect and primary author of libc++
+
+N: Sergej Jaskiewicz
+E: jaskiewiczs@icloud.com
+D: Minor improvements in the testing infrastructure
+
+N: Hyeon-bin Jeong
+E: tuhertz@gmail.com
+D: Minor patches and bug fixes.
+
+N: Argyrios Kyrtzidis
+E: kyrtzidis@apple.com
+D: Bug fixes.
+
+N: Bruce Mitchener, Jr.
+E: bruce.mitchener@gmail.com
+D: Emscripten-related changes.
+
+N: Michel Morin
+E: mimomorin@gmail.com
+D: Minor patches to is_convertible.
+
+N: Andrew Morrow
+E: andrew.c.morrow@gmail.com
+D: Minor patches and Linux fixes.
+
+N: Michael Park
+E: mcypark@gmail.com
+D: Implementation of <variant>.
+
+N: Arvid Picciani
+E: aep at exys dot org
+D: Minor patches and musl port.
+
+N: Bjorn Reese
+E: breese@users.sourceforge.net
+D: Initial regex prototype
+
+N: Nico Rieck
+E: nico.rieck@gmail.com
+D: Windows fixes
+
+N: Jon Roelofs
+E: jroelofS@jroelofs.com
+D: Remote testing, Newlib port, baremetal/single-threaded support.
+
+N: Kent Ross
+E: k@mad.cash
+D: Patches for operator<=> support
+
+N: Jonathan Sauer
+D: Minor patches, mostly related to constexpr
+
+N: Craig Silverstein
+E: csilvers@google.com
+D: Implemented Cityhash as the string hash function on 64-bit machines
+
+N: Richard Smith
+D: Minor patches.
+
+N: Joerg Sonnenberger
+E: joerg@NetBSD.org
+D: NetBSD port.
+
+N: Stephan Tolksdorf
+E: st@quanttec.com
+D: Minor <atomic> fix
+
+N: Ruben Van Boxem
+E: vanboxem dot ruben at gmail dot com
+D: Initial Windows patches.
+
+N: Michael van der Westhuizen
+E: r1mikey at gmail dot com
+
+N: Larisse Voufo
+D: Minor patches.
+
+N: Klaas de Vries
+E: klaas at klaasgaaf dot nl
+D: Minor bug fix.
+
+N: Zhang Xiongpang
+E: zhangxiongpang@gmail.com
+D: Minor patches and bug fixes.
+
+N: Xing Xue
+E: xingxue@ca.ibm.com
+D: AIX port
+
+N: Jeffrey Yasskin
+E: jyasskin@gmail.com
+E: jyasskin@google.com
+D: Linux fixes.
+
+N: Zhihao Yuan
+E: lichray@gmail.com
+D: Standard compatibility fixes.
+
+
+====================File: import====================
+#!/bin/sh -e
+
+rev=1e628d0c
+output_dir="libcxx-r$rev"
+if [ -z $1 ] ; then
+    git clone https://github.com/llvm/llvm-project.git --no-checkout "$output_dir/tmp"
+else
+    git clone --local --no-checkout $1 "$output_dir/tmp"
+fi
+cd "$output_dir/tmp"
+git checkout "$rev"
+cp -R libcxx/include ../include
+cp -R libcxx/src ../src
+cp libcxx/.clang-format ../.clang-format
+cp libcxx/CREDITS.TXT ../CREDITS.TXT
+cp libcxx/LICENSE.TXT ../LICENSE.TXT
+cd ..
+rm -rf tmp
+rm src/CMakeLists.txt include/CMakeLists.txt
+
+# Fix tabs and trailing spaces
+find -type f | xargs sed -e 's/\t/    /g' -e 's/ *$//' -i
+
+
+====================File: include/any====================
+// -*- C++ -*-
+//===------------------------------ any -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_ANY
+#define _LIBCPP_ANY
+
+/*
+   any synopsis
+
+namespace std {
+
+  class bad_any_cast : public bad_cast
+  {
+  public:
+    virtual const char* what() const noexcept;
+  };
+
+  class any
+  {
+  public:
+
+    // 6.3.1 any construct/destruct
+    any() noexcept;
+
+    any(const any& other);
+    any(any&& other) noexcept;
+
+    template <class ValueType>
+      any(ValueType&& value);
+
+    ~any();
+
+    // 6.3.2 any assignments
+    any& operator=(const any& rhs);
+    any& operator=(any&& rhs) noexcept;
+
+    template <class ValueType>
+      any& operator=(ValueType&& rhs);
+
+    // 6.3.3 any modifiers
+    template <class ValueType, class... Args>
+      decay_t<ValueType>& emplace(Args&&... args);
+    template <class ValueType, class U, class... Args>
+      decay_t<ValueType>& emplace(initializer_list<U>, Args&&...);
+    void reset() noexcept;
+    void swap(any& rhs) noexcept;
+
+    // 6.3.4 any observers
+    bool has_value() const noexcept;
+    const type_info& type() const noexcept;
+  };
+
+   // 6.4 Non-member functions
+  void swap(any& x, any& y) noexcept;
+
+  template <class T, class ...Args>
+    any make_any(Args&& ...args);
+  template <class T, class U, class ...Args>
+    any make_any(initializer_list<U>, Args&& ...args);
+
+  template<class ValueType>
+    ValueType any_cast(const any& operand);
+  template<class ValueType>
+    ValueType any_cast(any& operand);
+  template<class ValueType>
+    ValueType any_cast(any&& operand);
+
+  template<class ValueType>
+    const ValueType* any_cast(const any* operand) noexcept;
+  template<class ValueType>
+    ValueType* any_cast(any* operand) noexcept;
+
+} // namespace std
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <__utility/forward.h>
+#include <cstdlib>
+#include <memory>
+#include <type_traits>
+#include <typeinfo>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+namespace std {
+class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_BAD_ANY_CAST bad_any_cast : public bad_cast
+{
+public:
+    virtual const char* what() const _NOEXCEPT;
+};
+} // namespace std
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
+void __throw_bad_any_cast()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw bad_any_cast();
+#else
+    _VSTD::abort();
+#endif
+}
+
+// Forward declarations
+class _LIBCPP_TEMPLATE_VIS any;
+
+template <class _ValueType>
+_LIBCPP_INLINE_VISIBILITY
+add_pointer_t<add_const_t<_ValueType>>
+any_cast(any const *) _NOEXCEPT;
+
+template <class _ValueType>
+_LIBCPP_INLINE_VISIBILITY
+add_pointer_t<_ValueType> any_cast(any *) _NOEXCEPT;
+
+namespace __any_imp
+{
+  using _Buffer = aligned_storage_t<3*sizeof(void*), alignment_of<void*>::value>;
+
+  template <class _Tp>
+  using _IsSmallObject = integral_constant<bool
+        , sizeof(_Tp) <= sizeof(_Buffer)
+          && alignment_of<_Buffer>::value
+             % alignment_of<_Tp>::value == 0
+          && is_nothrow_move_constructible<_Tp>::value
+        >;
+
+  enum class _Action {
+    _Destroy,
+    _Copy,
+    _Move,
+    _Get,
+    _TypeInfo
+  };
+
+  template <class _Tp> struct _SmallHandler;
+  template <class _Tp> struct _LargeHandler;
+
+  template <class _Tp>
+  struct  _LIBCPP_TEMPLATE_VIS __unique_typeinfo { static constexpr int __id = 0; };
+  template <class _Tp> constexpr int __unique_typeinfo<_Tp>::__id;
+
+  template <class _Tp>
+  inline _LIBCPP_INLINE_VISIBILITY
+  constexpr const void* __get_fallback_typeid() {
+      return &__unique_typeinfo<remove_cv_t<remove_reference_t<_Tp>>>::__id;
+  }
+
+  template <class _Tp>
+  inline _LIBCPP_INLINE_VISIBILITY
+  bool __compare_typeid(type_info const* __id, const void* __fallback_id)
+  {
+#if !defined(_LIBCPP_NO_RTTI)
+      if (__id && *__id == typeid(_Tp))
+          return true;
+#endif
+      if (!__id && __fallback_id == __any_imp::__get_fallback_typeid<_Tp>())
+          return true;
+      return false;
+  }
+
+  template <class _Tp>
+  using _Handler = conditional_t<
+    _IsSmallObject<_Tp>::value, _SmallHandler<_Tp>, _LargeHandler<_Tp>>;
+
+} // namespace __any_imp
+
+class _LIBCPP_TEMPLATE_VIS any
+{
+public:
+  // construct/destruct
+  _LIBCPP_INLINE_VISIBILITY
+  constexpr any() _NOEXCEPT : __h(nullptr) {}
+
+  _LIBCPP_INLINE_VISIBILITY
+  any(any const & __other) : __h(nullptr)
+  {
+    if (__other.__h) __other.__call(_Action::_Copy, this);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  any(any && __other) _NOEXCEPT : __h(nullptr)
+  {
+    if (__other.__h) __other.__call(_Action::_Move, this);
+  }
+
+  template <
+      class _ValueType
+    , class _Tp = decay_t<_ValueType>
+    , class = enable_if_t<
+        !is_same<_Tp, any>::value &&
+        !__is_inplace_type<_ValueType>::value &&
+        is_copy_constructible<_Tp>::value>
+    >
+  _LIBCPP_INLINE_VISIBILITY
+  any(_ValueType && __value);
+
+  template <class _ValueType, class ..._Args,
+    class _Tp = decay_t<_ValueType>,
+    class = enable_if_t<
+        is_constructible<_Tp, _Args...>::value &&
+        is_copy_constructible<_Tp>::value
+    >
+  >
+  _LIBCPP_INLINE_VISIBILITY
+  explicit any(in_place_type_t<_ValueType>, _Args&&... __args);
+
+  template <class _ValueType, class _Up, class ..._Args,
+    class _Tp = decay_t<_ValueType>,
+    class = enable_if_t<
+        is_constructible<_Tp, initializer_list<_Up>&, _Args...>::value &&
+        is_copy_constructible<_Tp>::value>
+  >
+  _LIBCPP_INLINE_VISIBILITY
+  explicit any(in_place_type_t<_ValueType>, initializer_list<_Up>, _Args&&... __args);
+
+  _LIBCPP_INLINE_VISIBILITY
+  ~any() { this->reset(); }
+
+  // assignments
+  _LIBCPP_INLINE_VISIBILITY
+  any & operator=(any const & __rhs) {
+    any(__rhs).swap(*this);
+    return *this;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  any & operator=(any && __rhs) _NOEXCEPT {
+    any(_VSTD::move(__rhs)).swap(*this);
+    return *this;
+  }
+
+  template <
+      class _ValueType
+    , class _Tp = decay_t<_ValueType>
+    , class = enable_if_t<
+          !is_same<_Tp, any>::value
+          && is_copy_constructible<_Tp>::value>
+    >
+  _LIBCPP_INLINE_VISIBILITY
+  any & operator=(_ValueType && __rhs);
+
+  template <class _ValueType, class ..._Args,
+    class _Tp = decay_t<_ValueType>,
+    class = enable_if_t<
+        is_constructible<_Tp, _Args...>::value &&
+        is_copy_constructible<_Tp>::value>
+    >
+  _LIBCPP_INLINE_VISIBILITY
+  _Tp& emplace(_Args&&... args);
+
+  template <class _ValueType, class _Up, class ..._Args,
+    class _Tp = decay_t<_ValueType>,
+    class = enable_if_t<
+        is_constructible<_Tp, initializer_list<_Up>&, _Args...>::value &&
+        is_copy_constructible<_Tp>::value>
+  >
+  _LIBCPP_INLINE_VISIBILITY
+  _Tp& emplace(initializer_list<_Up>, _Args&&...);
+
+  // 6.3.3 any modifiers
+  _LIBCPP_INLINE_VISIBILITY
+  void reset() _NOEXCEPT { if (__h) this->__call(_Action::_Destroy); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void swap(any & __rhs) _NOEXCEPT;
+
+  // 6.3.4 any observers
+  _LIBCPP_INLINE_VISIBILITY
+  bool has_value() const _NOEXCEPT { return __h != nullptr; }
+
+#if !defined(_LIBCPP_NO_RTTI)
+  _LIBCPP_INLINE_VISIBILITY
+  const type_info & type() const _NOEXCEPT {
+    if (__h) {
+        return *static_cast<type_info const *>(this->__call(_Action::_TypeInfo));
+    } else {
+        return typeid(void);
+    }
+  }
+#endif
+
+private:
+    typedef __any_imp::_Action _Action;
+    using _HandleFuncPtr =  void* (*)(_Action, any const *, any *, const type_info *,
+      const void* __fallback_info);
+
+    union _Storage {
+        constexpr _Storage() : __ptr(nullptr) {}
+        void *  __ptr;
+        __any_imp::_Buffer __buf;
+    };
+
+    _LIBCPP_INLINE_VISIBILITY
+    void * __call(_Action __a, any * __other = nullptr,
+                  type_info const * __info = nullptr,
+                   const void* __fallback_info = nullptr) const
+    {
+        return __h(__a, this, __other, __info, __fallback_info);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void * __call(_Action __a, any * __other = nullptr,
+                  type_info const * __info = nullptr,
+                  const void* __fallback_info = nullptr)
+    {
+        return __h(__a, this, __other, __info, __fallback_info);
+    }
+
+    template <class>
+    friend struct __any_imp::_SmallHandler;
+    template <class>
+    friend struct __any_imp::_LargeHandler;
+
+    template <class _ValueType>
+    friend add_pointer_t<add_const_t<_ValueType>>
+    any_cast(any const *) _NOEXCEPT;
+
+    template <class _ValueType>
+    friend add_pointer_t<_ValueType>
+    any_cast(any *) _NOEXCEPT;
+
+    _HandleFuncPtr __h = nullptr;
+    _Storage __s;
+};
+
+namespace __any_imp
+{
+  template <class _Tp>
+  struct _LIBCPP_TEMPLATE_VIS _SmallHandler
+  {
+     _LIBCPP_INLINE_VISIBILITY
+     static void* __handle(_Action __act, any const * __this, any * __other,
+                           type_info const * __info, const void* __fallback_info)
+     {
+        switch (__act)
+        {
+        case _Action::_Destroy:
+          __destroy(const_cast<any &>(*__this));
+          return nullptr;
+        case _Action::_Copy:
+            __copy(*__this, *__other);
+            return nullptr;
+        case _Action::_Move:
+          __move(const_cast<any &>(*__this), *__other);
+          return nullptr;
+        case _Action::_Get:
+            return __get(const_cast<any &>(*__this), __info, __fallback_info);
+        case _Action::_TypeInfo:
+          return __type_info();
+        }
+    }
+
+    template <class ..._Args>
+    _LIBCPP_INLINE_VISIBILITY
+    static _Tp& __create(any & __dest, _Args&&... __args) {
+        typedef allocator<_Tp> _Alloc;
+        typedef allocator_traits<_Alloc> _ATraits;
+        _Alloc __a;
+        _Tp * __ret = static_cast<_Tp*>(static_cast<void*>(&__dest.__s.__buf));
+        _ATraits::construct(__a, __ret, _VSTD::forward<_Args>(__args)...);
+        __dest.__h = &_SmallHandler::__handle;
+        return *__ret;
+    }
+
+  private:
+    _LIBCPP_INLINE_VISIBILITY
+    static void __destroy(any & __this) {
+        typedef allocator<_Tp> _Alloc;
+        typedef allocator_traits<_Alloc> _ATraits;
+        _Alloc __a;
+        _Tp * __p = static_cast<_Tp *>(static_cast<void*>(&__this.__s.__buf));
+        _ATraits::destroy(__a, __p);
+        __this.__h = nullptr;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void __copy(any const & __this, any & __dest) {
+        _SmallHandler::__create(__dest, *static_cast<_Tp const *>(
+            static_cast<void const *>(&__this.__s.__buf)));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void __move(any & __this, any & __dest) {
+        _SmallHandler::__create(__dest, _VSTD::move(
+            *static_cast<_Tp*>(static_cast<void*>(&__this.__s.__buf))));
+        __destroy(__this);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void* __get(any & __this,
+                       type_info const * __info,
+                       const void* __fallback_id)
+    {
+        if (__any_imp::__compare_typeid<_Tp>(__info, __fallback_id))
+            return static_cast<void*>(&__this.__s.__buf);
+        return nullptr;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void* __type_info()
+    {
+#if !defined(_LIBCPP_NO_RTTI)
+        return const_cast<void*>(static_cast<void const *>(&typeid(_Tp)));
+#else
+        return nullptr;
+#endif
+    }
+  };
+
+  template <class _Tp>
+  struct _LIBCPP_TEMPLATE_VIS _LargeHandler
+  {
+    _LIBCPP_INLINE_VISIBILITY
+    static void* __handle(_Action __act, any const * __this,
+                          any * __other, type_info const * __info,
+                          void const* __fallback_info)
+    {
+        switch (__act)
+        {
+        case _Action::_Destroy:
+          __destroy(const_cast<any &>(*__this));
+          return nullptr;
+        case _Action::_Copy:
+          __copy(*__this, *__other);
+          return nullptr;
+        case _Action::_Move:
+          __move(const_cast<any &>(*__this), *__other);
+          return nullptr;
+        case _Action::_Get:
+            return __get(const_cast<any &>(*__this), __info, __fallback_info);
+        case _Action::_TypeInfo:
+          return __type_info();
+        }
+    }
+
+    template <class ..._Args>
+    _LIBCPP_INLINE_VISIBILITY
+    static _Tp& __create(any & __dest, _Args&&... __args) {
+        typedef allocator<_Tp> _Alloc;
+        typedef allocator_traits<_Alloc> _ATraits;
+        typedef __allocator_destructor<_Alloc> _Dp;
+        _Alloc __a;
+        unique_ptr<_Tp, _Dp> __hold(_ATraits::allocate(__a, 1), _Dp(__a, 1));
+        _Tp * __ret = __hold.get();
+        _ATraits::construct(__a, __ret, _VSTD::forward<_Args>(__args)...);
+        __dest.__s.__ptr = __hold.release();
+        __dest.__h = &_LargeHandler::__handle;
+        return *__ret;
+    }
+
+  private:
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void __destroy(any & __this){
+        typedef allocator<_Tp> _Alloc;
+        typedef allocator_traits<_Alloc> _ATraits;
+        _Alloc __a;
+        _Tp * __p = static_cast<_Tp *>(__this.__s.__ptr);
+        _ATraits::destroy(__a, __p);
+        _ATraits::deallocate(__a, __p, 1);
+        __this.__h = nullptr;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void __copy(any const & __this, any & __dest) {
+        _LargeHandler::__create(__dest, *static_cast<_Tp const *>(__this.__s.__ptr));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void __move(any & __this, any & __dest) {
+      __dest.__s.__ptr = __this.__s.__ptr;
+      __dest.__h = &_LargeHandler::__handle;
+      __this.__h = nullptr;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void* __get(any & __this, type_info const * __info,
+                       void const* __fallback_info)
+    {
+        if (__any_imp::__compare_typeid<_Tp>(__info, __fallback_info))
+            return static_cast<void*>(__this.__s.__ptr);
+        return nullptr;
+
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void* __type_info()
+    {
+#if !defined(_LIBCPP_NO_RTTI)
+        return const_cast<void*>(static_cast<void const *>(&typeid(_Tp)));
+#else
+        return nullptr;
+#endif
+    }
+  };
+
+} // namespace __any_imp
+
+
+template <class _ValueType, class _Tp, class>
+any::any(_ValueType && __v) : __h(nullptr)
+{
+  __any_imp::_Handler<_Tp>::__create(*this, _VSTD::forward<_ValueType>(__v));
+}
+
+template <class _ValueType, class ..._Args, class _Tp, class>
+any::any(in_place_type_t<_ValueType>, _Args&&... __args) {
+  __any_imp::_Handler<_Tp>::__create(*this, _VSTD::forward<_Args>(__args)...);
+}
+
+template <class _ValueType, class _Up, class ..._Args, class _Tp, class>
+any::any(in_place_type_t<_ValueType>, initializer_list<_Up> __il, _Args&&... __args) {
+  __any_imp::_Handler<_Tp>::__create(*this, __il, _VSTD::forward<_Args>(__args)...);
+}
+
+template <class _ValueType, class, class>
+inline _LIBCPP_INLINE_VISIBILITY
+any & any::operator=(_ValueType && __v)
+{
+  any(_VSTD::forward<_ValueType>(__v)).swap(*this);
+  return *this;
+}
+
+template <class _ValueType, class ..._Args, class _Tp, class>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp& any::emplace(_Args&&... __args) {
+  reset();
+  return __any_imp::_Handler<_Tp>::__create(*this, _VSTD::forward<_Args>(__args)...);
+}
+
+template <class _ValueType, class _Up, class ..._Args, class _Tp, class>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp& any::emplace(initializer_list<_Up> __il, _Args&&... __args) {
+  reset();
+  return __any_imp::_Handler<_Tp>::__create(*this, __il, _VSTD::forward<_Args>(__args)...);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void any::swap(any & __rhs) _NOEXCEPT
+{
+    if (this == &__rhs)
+      return;
+    if (__h && __rhs.__h) {
+        any __tmp;
+        __rhs.__call(_Action::_Move, &__tmp);
+        this->__call(_Action::_Move, &__rhs);
+        __tmp.__call(_Action::_Move, this);
+    }
+    else if (__h) {
+        this->__call(_Action::_Move, &__rhs);
+    }
+    else if (__rhs.__h) {
+        __rhs.__call(_Action::_Move, this);
+    }
+}
+
+// 6.4 Non-member functions
+
+inline _LIBCPP_INLINE_VISIBILITY
+void swap(any & __lhs, any & __rhs) _NOEXCEPT
+{
+    __lhs.swap(__rhs);
+}
+
+template <class _Tp, class ..._Args>
+inline _LIBCPP_INLINE_VISIBILITY
+any make_any(_Args&&... __args) {
+    return any(in_place_type<_Tp>, _VSTD::forward<_Args>(__args)...);
+}
+
+template <class _Tp, class _Up, class ..._Args>
+inline _LIBCPP_INLINE_VISIBILITY
+any make_any(initializer_list<_Up> __il, _Args&&... __args) {
+    return any(in_place_type<_Tp>, __il, _VSTD::forward<_Args>(__args)...);
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
+_ValueType any_cast(any const & __v)
+{
+    using _RawValueType = __uncvref_t<_ValueType>;
+    static_assert(is_constructible<_ValueType, _RawValueType const &>::value,
+                  "ValueType is required to be a const lvalue reference "
+                  "or a CopyConstructible type");
+    auto __tmp = _VSTD::any_cast<add_const_t<_RawValueType>>(&__v);
+    if (__tmp == nullptr)
+        __throw_bad_any_cast();
+    return static_cast<_ValueType>(*__tmp);
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
+_ValueType any_cast(any & __v)
+{
+    using _RawValueType = __uncvref_t<_ValueType>;
+    static_assert(is_constructible<_ValueType, _RawValueType &>::value,
+                  "ValueType is required to be an lvalue reference "
+                  "or a CopyConstructible type");
+    auto __tmp = _VSTD::any_cast<_RawValueType>(&__v);
+    if (__tmp == nullptr)
+        __throw_bad_any_cast();
+    return static_cast<_ValueType>(*__tmp);
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
+_ValueType any_cast(any && __v)
+{
+    using _RawValueType = __uncvref_t<_ValueType>;
+    static_assert(is_constructible<_ValueType, _RawValueType>::value,
+                  "ValueType is required to be an rvalue reference "
+                  "or a CopyConstructible type");
+    auto __tmp = _VSTD::any_cast<_RawValueType>(&__v);
+    if (__tmp == nullptr)
+        __throw_bad_any_cast();
+    return static_cast<_ValueType>(_VSTD::move(*__tmp));
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+add_pointer_t<add_const_t<_ValueType>>
+any_cast(any const * __any) _NOEXCEPT
+{
+    static_assert(!is_reference<_ValueType>::value,
+                  "_ValueType may not be a reference.");
+    return _VSTD::any_cast<_ValueType>(const_cast<any *>(__any));
+}
+
+template <class _RetType>
+inline _LIBCPP_INLINE_VISIBILITY
+_RetType __pointer_or_func_cast(void* __p, /*IsFunction*/false_type) noexcept {
+  return static_cast<_RetType>(__p);
+}
+
+template <class _RetType>
+inline _LIBCPP_INLINE_VISIBILITY
+_RetType __pointer_or_func_cast(void*, /*IsFunction*/true_type) noexcept {
+  return nullptr;
+}
+
+template <class _ValueType>
+add_pointer_t<_ValueType>
+any_cast(any * __any) _NOEXCEPT
+{
+    using __any_imp::_Action;
+    static_assert(!is_reference<_ValueType>::value,
+                  "_ValueType may not be a reference.");
+    typedef typename add_pointer<_ValueType>::type _ReturnType;
+    if (__any && __any->__h) {
+      void *__p = __any->__call(_Action::_Get, nullptr,
+#if !defined(_LIBCPP_NO_RTTI)
+                          &typeid(_ValueType),
+#else
+                          nullptr,
+#endif
+                          __any_imp::__get_fallback_typeid<_ValueType>());
+        return _VSTD::__pointer_or_func_cast<_ReturnType>(
+            __p, is_function<_ValueType>{});
+    }
+    return nullptr;
+}
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_ANY
+
+
+====================File: include/exception====================
+// -*- C++ -*-
+//===-------------------------- exception ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXCEPTION
+#define _LIBCPP_EXCEPTION
+
+/*
+    exception synopsis
+
+namespace std
+{
+
+class exception
+{
+public:
+    exception() noexcept;
+    exception(const exception&) noexcept;
+    exception& operator=(const exception&) noexcept;
+    virtual ~exception() noexcept;
+    virtual const char* what() const noexcept;
+};
+
+class bad_exception
+    : public exception
+{
+public:
+    bad_exception() noexcept;
+    bad_exception(const bad_exception&) noexcept;
+    bad_exception& operator=(const bad_exception&) noexcept;
+    virtual ~bad_exception() noexcept;
+    virtual const char* what() const noexcept;
+};
+
+typedef void (*unexpected_handler)();
+unexpected_handler set_unexpected(unexpected_handler  f ) noexcept;
+unexpected_handler get_unexpected() noexcept;
+[[noreturn]] void unexpected();
+
+typedef void (*terminate_handler)();
+terminate_handler set_terminate(terminate_handler  f ) noexcept;
+terminate_handler get_terminate() noexcept;
+[[noreturn]] void terminate() noexcept;
+
+bool uncaught_exception()  noexcept;
+int  uncaught_exceptions() noexcept;  // C++17
+
+typedef unspecified exception_ptr;
+
+exception_ptr current_exception() noexcept;
+void rethrow_exception [[noreturn]] (exception_ptr p);
+template<class E> exception_ptr make_exception_ptr(E e) noexcept;
+
+class nested_exception
+{
+public:
+    nested_exception() noexcept;
+    nested_exception(const nested_exception&) noexcept = default;
+    nested_exception& operator=(const nested_exception&) noexcept = default;
+    virtual ~nested_exception() = default;
+
+    // access functions
+    [[noreturn]] void rethrow_nested() const;
+    exception_ptr nested_ptr() const noexcept;
+};
+
+template <class T> [[noreturn]] void throw_with_nested(T&& t);
+template <class E> void rethrow_if_nested(const E& e);
+
+}  // std
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <__memory/addressof.h>
+#include <cstddef>
+#include <cstdlib>
+#include <type_traits>
+#include <version>
+
+#if defined(_LIBCPP_ABI_VCRUNTIME)
+#include <vcruntime_exception.h>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+namespace std  // purposefully not using versioning namespace
+{
+
+#if !defined(_LIBCPP_ABI_VCRUNTIME)
+class _LIBCPP_EXCEPTION_ABI exception
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY exception() _NOEXCEPT {}
+    _LIBCPP_INLINE_VISIBILITY exception(const exception&) _NOEXCEPT = default;
+
+    virtual ~exception() _NOEXCEPT;
+    virtual const char* what() const _NOEXCEPT;
+};
+
+class _LIBCPP_EXCEPTION_ABI bad_exception
+    : public exception
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY bad_exception() _NOEXCEPT {}
+    virtual ~bad_exception() _NOEXCEPT;
+    virtual const char* what() const _NOEXCEPT;
+};
+#endif // !_LIBCPP_ABI_VCRUNTIME
+
+#if _LIBCPP_STD_VER <= 14 \
+    || defined(_LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS) \
+    || defined(_LIBCPP_BUILDING_LIBRARY)
+typedef void (*unexpected_handler)();
+_LIBCPP_FUNC_VIS unexpected_handler set_unexpected(unexpected_handler) _NOEXCEPT;
+_LIBCPP_FUNC_VIS unexpected_handler get_unexpected() _NOEXCEPT;
+_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void unexpected();
+#endif
+
+typedef void (*terminate_handler)();
+_LIBCPP_FUNC_VIS terminate_handler set_terminate(terminate_handler) _NOEXCEPT;
+_LIBCPP_FUNC_VIS terminate_handler get_terminate() _NOEXCEPT;
+_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void terminate() _NOEXCEPT;
+
+_LIBCPP_FUNC_VIS bool uncaught_exception() _NOEXCEPT;
+_LIBCPP_FUNC_VIS _LIBCPP_AVAILABILITY_UNCAUGHT_EXCEPTIONS int uncaught_exceptions() _NOEXCEPT;
+
+class _LIBCPP_TYPE_VIS exception_ptr;
+
+_LIBCPP_FUNC_VIS exception_ptr current_exception() _NOEXCEPT;
+_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void rethrow_exception(exception_ptr);
+
+class _LIBCPP_TYPE_VIS exception_ptr
+{
+    void* __ptr_;
+public:
+    _LIBCPP_INLINE_VISIBILITY exception_ptr() _NOEXCEPT : __ptr_() {}
+    _LIBCPP_INLINE_VISIBILITY exception_ptr(nullptr_t) _NOEXCEPT : __ptr_() {}
+
+    exception_ptr(const exception_ptr&) _NOEXCEPT;
+    exception_ptr& operator=(const exception_ptr&) _NOEXCEPT;
+    ~exception_ptr() _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY explicit operator bool() const _NOEXCEPT
+    {return __ptr_ != nullptr;}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
+        {return __x.__ptr_ == __y.__ptr_;}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
+        {return !(__x == __y);}
+
+    friend _LIBCPP_FUNC_VIS void swap(exception_ptr& __x, exception_ptr& __y) _NOEXCEPT
+    {
+        void* __tmp = __x.__ptr_;
+        __x.__ptr_ = __y.__ptr_;
+        __y.__ptr_ = __tmp;
+    }
+
+    friend _LIBCPP_FUNC_VIS exception_ptr current_exception() _NOEXCEPT;
+    friend _LIBCPP_FUNC_VIS void rethrow_exception(exception_ptr);
+};
+
+#ifndef _LIBCPP_ABI_MICROSOFT
+
+template<class _Ep>
+_LIBCPP_INLINE_VISIBILITY exception_ptr
+make_exception_ptr(_Ep __e) _NOEXCEPT
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+        throw __e;
+    }
+    catch (...)
+    {
+        return current_exception();
+    }
+#else
+    ((void)__e);
+    _VSTD::abort();
+#endif
+}
+
+#else // _LIBCPP_ABI_MICROSOFT
+
+_LIBCPP_FUNC_VIS exception_ptr __copy_exception_ptr(void *__exception, const void* __ptr);
+
+// This is a built-in template function which automagically extracts the required
+// information.
+template <class _E> void *__GetExceptionInfo(_E);
+
+template<class _Ep>
+exception_ptr
+make_exception_ptr(_Ep __e) _NOEXCEPT
+{
+  return __copy_exception_ptr(_VSTD::addressof(__e), __GetExceptionInfo(__e));
+}
+
+#endif // _LIBCPP_ABI_MICROSOFT
+// nested_exception
+
+class _LIBCPP_EXCEPTION_ABI nested_exception
+{
+    exception_ptr __ptr_;
+public:
+    nested_exception() _NOEXCEPT;
+//     nested_exception(const nested_exception&) noexcept = default;
+//     nested_exception& operator=(const nested_exception&) noexcept = default;
+    virtual ~nested_exception() _NOEXCEPT;
+
+    // access functions
+    _LIBCPP_NORETURN void rethrow_nested() const;
+    _LIBCPP_INLINE_VISIBILITY exception_ptr nested_ptr() const _NOEXCEPT {return __ptr_;}
+};
+
+template <class _Tp>
+struct __nested
+    : public _Tp,
+      public nested_exception
+{
+    _LIBCPP_INLINE_VISIBILITY explicit __nested(const _Tp& __t) : _Tp(__t) {}
+};
+
+#ifndef _LIBCPP_NO_EXCEPTIONS
+template <class _Tp, class _Up, bool>
+struct __throw_with_nested;
+
+template <class _Tp, class _Up>
+struct __throw_with_nested<_Tp, _Up, true> {
+    _LIBCPP_NORETURN static inline _LIBCPP_INLINE_VISIBILITY void
+    __do_throw(_Tp&& __t)
+    {
+        throw __nested<_Up>(static_cast<_Tp&&>(__t));
+    }
+};
+
+template <class _Tp, class _Up>
+struct __throw_with_nested<_Tp, _Up, false> {
+    _LIBCPP_NORETURN static inline _LIBCPP_INLINE_VISIBILITY void
+#ifndef _LIBCPP_CXX03_LANG
+    __do_throw(_Tp&& __t)
+#else
+    __do_throw (_Tp& __t)
+#endif // _LIBCPP_CXX03_LANG
+    {
+        throw static_cast<_Tp&&>(__t);
+    }
+};
+#endif
+
+template <class _Tp>
+_LIBCPP_NORETURN
+void
+throw_with_nested(_Tp&& __t)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    typedef typename decay<_Tp>::type _Up;
+    static_assert( is_copy_constructible<_Up>::value, "type thrown must be CopyConstructible");
+    __throw_with_nested<_Tp, _Up,
+        is_class<_Up>::value &&
+        !is_base_of<nested_exception, _Up>::value &&
+        !__libcpp_is_final<_Up>::value>::
+            __do_throw(static_cast<_Tp&&>(__t));
+#else
+    ((void)__t);
+    // FIXME: Make this abort
+#endif
+}
+
+template <class _From, class _To>
+struct __can_dynamic_cast : public _LIBCPP_BOOL_CONSTANT(
+              is_polymorphic<_From>::value &&
+                 (!is_base_of<_To, _From>::value ||
+                   is_convertible<const _From*, const _To*>::value)) {};
+
+template <class _Ep>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+rethrow_if_nested(const _Ep& __e,
+                  typename enable_if< __can_dynamic_cast<_Ep, nested_exception>::value>::type* = 0)
+{
+    const nested_exception* __nep = dynamic_cast<const nested_exception*>(_VSTD::addressof(__e));
+    if (__nep)
+        __nep->rethrow_nested();
+}
+
+template <class _Ep>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+rethrow_if_nested(const _Ep&,
+                  typename enable_if<!__can_dynamic_cast<_Ep, nested_exception>::value>::type* = 0)
+{
+}
+
+}  // std
+
+#endif // _LIBCPP_EXCEPTION
+
+
+====================File: include/experimental/list====================
+// -*- C++ -*-
+//===--------------------------- list ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_LIST
+#define _LIBCPP_EXPERIMENTAL_LIST
+/*
+    experimental/list synopsis
+
+// C++1z
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+namespace pmr {
+
+  template <class T>
+  using list = std::list<T,polymorphic_allocator<T>>;
+
+} // namespace pmr
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <list>
+#include <experimental/memory_resource>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+template <class _ValueT>
+using list = _VSTD::list<_ValueT, polymorphic_allocator<_ValueT>>;
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR
+
+#endif /* _LIBCPP_EXPERIMENTAL_LIST */
+
+
+====================File: include/format====================
+// -*- C++ -*-
+//===--------------------------- format -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_FORMAT
+#define _LIBCPP_FORMAT
+
+/*
+
+namespace std {
+  // [format.context], class template basic_format_context
+  template<class Out, class charT>
+  class basic_format_context {
+    basic_format_args<basic_format_context> args_;      // exposition only
+    Out out_;                                           // exposition only
+
+  public:
+    using iterator = Out;
+    using char_type = charT;
+    template<class T> using formatter_type = formatter<T, charT>;
+
+    basic_format_arg<basic_format_context> arg(size_t id) const;
+    std::locale locale();
+
+    iterator out();
+    void advance_to(iterator it);
+  };
+  using format_context = basic_format_context<unspecified, char>;
+  using wformat_context = basic_format_context<unspecified, wchar_t>;
+
+  // [format.args], class template basic_format_args
+  template<class Context>
+  class basic_format_args {
+    size_t size_;                               // exposition only
+    const basic_format_arg<Context>* data_;     // exposition only
+
+  public:
+    basic_format_args() noexcept;
+
+    template<class... Args>
+      basic_format_args(const format-arg-store<Context, Args...>& store) noexcept;
+
+    basic_format_arg<Context> get(size_t i) const noexcept;
+  };
+  using format_args = basic_format_args<format_context>;
+  using wformat_args = basic_format_args<wformat_context>;
+
+
+  template<class Out, class charT>
+    using format_args_t = basic_format_args<basic_format_context<Out, charT>>;
+
+  // [format.functions], formatting functions
+  template<class... Args>
+    string format(string_view fmt, const Args&... args);
+  template<class... Args>
+    wstring format(wstring_view fmt, const Args&... args);
+  template<class... Args>
+    string format(const locale& loc, string_view fmt, const Args&... args);
+  template<class... Args>
+    wstring format(const locale& loc, wstring_view fmt, const Args&... args);
+
+  string vformat(string_view fmt, format_args args);
+  wstring vformat(wstring_view fmt, wformat_args args);
+  string vformat(const locale& loc, string_view fmt, format_args args);
+  wstring vformat(const locale& loc, wstring_view fmt, wformat_args args);
+
+  template<class Out, class... Args>
+    Out format_to(Out out, string_view fmt, const Args&... args);
+  template<class Out, class... Args>
+    Out format_to(Out out, wstring_view fmt, const Args&... args);
+  template<class Out, class... Args>
+    Out format_to(Out out, const locale& loc, string_view fmt, const Args&... args);
+  template<class Out, class... Args>
+    Out format_to(Out out, const locale& loc, wstring_view fmt, const Args&... args);
+
+  template<class Out>
+    Out vformat_to(Out out, string_view fmt,
+                   format_args_t<type_identity_t<Out>, char> args);
+  template<class Out>
+    Out vformat_to(Out out, wstring_view fmt,
+                   format_args_t<type_identity_t<Out>, wchar_t> args);
+  template<class Out>
+    Out vformat_to(Out out, const locale& loc, string_view fmt,
+                   format_args_t<type_identity_t<Out>, char> args);
+  template<class Out>
+    Out vformat_to(Out out, const locale& loc, wstring_view fmt,
+                   format_args_t<type_identity_t<Out>, wchar_t> args);
+
+  template<class Out> struct format_to_n_result {
+    Out out;
+    iter_difference_t<Out> size;
+  };
+
+ template<class Out, class... Args>
+    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
+                                        string_view fmt, const Args&... args);
+  template<class Out, class... Args>
+    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
+                                        wstring_view fmt, const Args&... args);
+  template<class Out, class... Args>
+    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
+                                        const locale& loc, string_view fmt,
+                                        const Args&... args);
+  template<class Out, class... Args>
+    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
+                                        const locale& loc, wstring_view fmt,
+                                        const Args&... args);
+
+  template<class... Args>
+    size_t formatted_size(string_view fmt, const Args&... args);
+  template<class... Args>
+    size_t formatted_size(wstring_view fmt, const Args&... args);
+  template<class... Args>
+    size_t formatted_size(const locale& loc, string_view fmt, const Args&... args);
+  template<class... Args>
+    size_t formatted_size(const locale& loc, wstring_view fmt, const Args&... args);
+
+  // [format.formatter], formatter
+  template<> struct formatter<char, char>;
+  template<> struct formatter<char, wchar_t>;
+  template<> struct formatter<wchar_t, wchar_t>;
+
+  template<> struct formatter<charT*, charT>;
+  template<> struct formatter<const charT*, charT>;
+  template<size_t N> struct formatter<const charT[N], charT>;
+  template<class traits, class Allocator>
+    struct formatter<basic_string<charT, traits, Allocator>, charT>;
+  template<class traits>
+    struct formatter<basic_string_view<charT, traits>, charT>;
+
+  // [format.parse.ctx], class template basic_format_parse_context
+  template<class charT>
+  class basic_format_parse_context {
+  public:
+    using char_type = charT;
+    using const_iterator = typename basic_string_view<charT>::const_iterator;
+    using iterator = const_iterator;
+
+  private:
+    iterator begin_;                                    // exposition only
+    iterator end_;                                      // exposition only
+    enum indexing { unknown, manual, automatic };       // exposition only
+    indexing indexing_;                                 // exposition only
+    size_t next_arg_id_;                                // exposition only
+    size_t num_args_;                                   // exposition only
+
+  public:
+    constexpr explicit basic_format_parse_context(basic_string_view<charT> fmt,
+                                                  size_t num_args = 0) noexcept;
+    basic_format_parse_context(const basic_format_parse_context&) = delete;
+    basic_format_parse_context& operator=(const basic_format_parse_context&) = delete;
+
+    constexpr const_iterator begin() const noexcept;
+    constexpr const_iterator end() const noexcept;
+    constexpr void advance_to(const_iterator it);
+
+    constexpr size_t next_arg_id();
+    constexpr void check_arg_id(size_t id);
+  };
+  using format_parse_context = basic_format_parse_context<char>;
+  using wformat_parse_context = basic_format_parse_context<wchar_t>;
+
+  // [format.arguments], arguments
+  // [format.arg], class template basic_format_arg
+  template<class Context>
+  class basic_format_arg {
+  public:
+    class handle;
+
+  private:
+    using char_type = typename Context::char_type;                              // exposition only
+
+    variant<monostate, bool, char_type,
+            int, unsigned int, long long int, unsigned long long int,
+            float, double, long double,
+            const char_type*, basic_string_view<char_type>,
+            const void*, handle> value;                                         // exposition only
+
+    template<class T> explicit basic_format_arg(const T& v) noexcept;           // exposition only
+    explicit basic_format_arg(float n) noexcept;                                // exposition only
+    explicit basic_format_arg(double n) noexcept;                               // exposition only
+    explicit basic_format_arg(long double n) noexcept;                          // exposition only
+    explicit basic_format_arg(const char_type* s);                              // exposition only
+
+    template<class traits>
+      explicit basic_format_arg(
+        basic_string_view<char_type, traits> s) noexcept;                       // exposition only
+
+    template<class traits, class Allocator>
+      explicit basic_format_arg(
+        const basic_string<char_type, traits, Allocator>& s) noexcept;          // exposition only
+
+    explicit basic_format_arg(nullptr_t) noexcept;                              // exposition only
+
+    template<class T>
+      explicit basic_format_arg(const T* p) noexcept;                           // exposition only
+
+  public:
+    basic_format_arg() noexcept;
+
+    explicit operator bool() const noexcept;
+  };
+
+  template<class Visitor, class Context>
+    see below visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg);
+
+  // [format.arg.store], class template format-arg-store
+  template<class Context, class... Args>
+  struct format-arg-store {      // exposition only
+    array<basic_format_arg<Context>, sizeof...(Args)> args;
+  };
+
+  template<class Context = format_context, class... Args>
+    format-arg-store<Context, Args...>
+      make_format_args(const Args&... args);
+  template<class... Args>
+    format-arg-store<wformat_context, Args...>
+      make_wformat_args(const Args&... args);
+
+  // [format.error], class format_error
+  class format_error : public runtime_error {
+  public:
+    explicit format_error(const string& what_arg);
+    explicit format_error(const char* what_arg);
+  };
+
+  // [format.parse.ctx], class template basic_format_parse_context
+  template<class charT>
+  class basic_format_parse_context {
+  public:
+    using char_type = charT;
+    using const_iterator = typename basic_string_view<charT>::const_iterator;
+    using iterator = const_iterator;
+
+  private:
+    iterator begin_;                                    // exposition only
+    iterator end_;                                      // exposition only
+    enum indexing { unknown, manual, automatic };       // exposition only
+    indexing indexing_;                                 // exposition only
+    size_t next_arg_id_;                                // exposition only
+    size_t num_args_;                                   // exposition only
+
+  public:
+    constexpr explicit basic_format_parse_context(basic_string_view<charT> fmt,
+                                                  size_t num_args = 0) noexcept;
+    basic_format_parse_context(const basic_format_parse_context&) = delete;
+    basic_format_parse_context& operator=(const basic_format_parse_context&) = delete;
+
+    constexpr const_iterator begin() const noexcept;
+    constexpr const_iterator end() const noexcept;
+    constexpr void advance_to(const_iterator it);
+
+    constexpr size_t next_arg_id();
+    constexpr void check_arg_id(size_t id);
+  };
+  using format_parse_context = basic_format_parse_context<char>;
+  using wformat_parse_context = basic_format_parse_context<wchar_t>;
+}
+
+*/
+
+// Make sure all feature-test macros are available.
+#include <version>
+// Enable the contents of the header only when libc++ was built with LIBCXX_ENABLE_INCOMPLETE_FEATURES.
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+
+#include <__config>
+#include <__debug>
+#include <__format/format_arg.h>
+#include <__format/format_args.h>
+#include <__format/format_context.h>
+#include <__format/format_error.h>
+#include <__format/format_parse_context.h>
+#include <__format/format_string.h>
+#include <__format/parser_std_format_spec.h>
+#include <__format/formatter.h>
+#include <__variant/monostate.h>
+#include <array>
+#include <concepts>
+#include <string>
+#include <string_view>
+#include <type_traits>
+
+#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#include <locale>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// TODO FMT Evaluate which templates should be external templates. This
+// improves the efficiency of the header. However since the header is still
+// under heavy development and not all classes are stable it makes no sense
+// to do this optimization now.
+
+using format_args = basic_format_args<format_context>;
+using wformat_args = basic_format_args<wformat_context>;
+
+template <class _OutIt, class _CharT>
+using format_args_t = basic_format_args<basic_format_context<_OutIt, _CharT>>;
+
+template <class _Context, class... _Args>
+struct _LIBCPP_TEMPLATE_VIS __format_arg_store {
+  // TODO FMT Use a built-in array.
+  array<basic_format_arg<_Context>, sizeof...(_Args)> __args;
+};
+
+template <class _Context = format_context, class... _Args>
+_LIBCPP_HIDE_FROM_ABI __format_arg_store<_Context, _Args...>
+make_format_args(const _Args&... __args) {
+  return {basic_format_arg<_Context>(__args)...};
+}
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI __format_arg_store<wformat_context, _Args...>
+make_wformat_args(const _Args&... __args) {
+  return _VSTD::make_format_args<wformat_context>(__args...);
+}
+
+namespace __format {
+template <class _Tp, class _CharT>
+struct _LIBCPP_TEMPLATE_VIS __formatter_char {
+  _LIBCPP_HIDE_FROM_ABI
+  auto parse(auto& __parse_ctx) -> decltype(__parse_ctx.begin()) {
+    // TODO FMT Implement this function.
+    return __parse_ctx.begin();
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  auto format(_Tp __c, auto& __ctx) -> decltype(__ctx.out()) {
+    // TODO FMT Implement the parsed formatting arguments.
+    auto __out_it = __ctx.out();
+    *__out_it++ = _CharT(__c);
+    return __out_it;
+  }
+};
+
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS __formatter_c_string {
+  _LIBCPP_HIDE_FROM_ABI
+  auto parse(auto& __parse_ctx) -> decltype(__parse_ctx.begin()) {
+    // TODO FMT Implement this function.
+    return __parse_ctx.begin();
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  auto format(const _CharT* __str, auto& __ctx) -> decltype(__ctx.out()) {
+    // TODO FMT Implement the parsed formatting arguments.
+    auto __out_it = __ctx.out();
+    while (*__str)
+      *__out_it++ = *__str++;
+    return __out_it;
+  }
+};
+
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS __formatter_string {
+  _LIBCPP_HIDE_FROM_ABI
+  auto parse(auto& __parse_ctx) -> decltype(__parse_ctx.begin()) {
+    // TODO FMT Implement this function.
+    return __parse_ctx.begin();
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  auto format(basic_string_view<_CharT> __str, auto& __ctx)
+      -> decltype(__ctx.out()) {
+    // TODO FMT Implement the parsed formatting arguments.
+    auto __out_it = __ctx.out();
+    for (const auto __c : __str)
+      *__out_it++ = __c;
+    return __out_it;
+  }
+};
+
+template <class _Tp, class _CharT>
+requires(is_arithmetic_v<_Tp> &&
+         !same_as<_Tp, bool>) struct _LIBCPP_HIDE_FROM_ABI
+    __formatter_arithmetic {
+  _LIBCPP_HIDE_FROM_ABI
+  auto parse(auto& __parse_ctx) -> decltype(__parse_ctx.begin()) {
+    // TODO FMT Implement
+    return __parse_ctx.begin();
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  auto format(_Tp __value, auto& __ctx) -> decltype(__ctx.out()) {
+    return __handle_format(__value, __ctx);
+  }
+
+private:
+  template <class _Uv>
+  _LIBCPP_HIDDEN static string
+  __convert(_Uv __value) requires(same_as<_CharT, char>) {
+    return _VSTD::to_string(__value);
+  }
+  template <class _Uv>
+  _LIBCPP_HIDDEN static wstring
+  __convert(_Uv __value) requires(same_as<_CharT, wchar_t>) {
+    return _VSTD::to_wstring(__value);
+  }
+
+  template <class _Uv>
+  _LIBCPP_HIDDEN auto __handle_format(_Uv __value, auto& __ctx)
+      -> decltype(__ctx.out())
+#ifndef _LIBCPP_HAS_NO_INT128
+          requires(!same_as<_Uv, __int128_t> && !same_as<_Uv, __uint128_t>)
+#endif
+  {
+    // TODO FMT Implement using formatting arguments
+    // TODO FMT Improve PoC since using std::to_string is inefficient.
+    // Note the code doesn't use std::string::iterator since the unit tests
+    // test with debug iterators and they fail with strings created from
+    // std::to_string.
+    auto __str = __convert(__value);
+    auto __out_it = __ctx.out();
+    for (size_t __i = 0, __e = __str.size(); __i != __e; ++__i)
+      *__out_it++ = __str[__i];
+    return __out_it;
+  }
+#ifndef _LIBCPP_HAS_NO_INT128
+  template <class _Uv>
+  _LIBCPP_HIDDEN auto __handle_format(_Uv __value, auto& __ctx)
+      -> decltype(__ctx.out()) requires(same_as<_Uv, __int128_t> ||
+                                        same_as<_Uv, __uint128_t>) {
+    using _To = conditional_t<is_signed_v<_Uv>, long long, unsigned long long>;
+    // TODO FMT Implement full 128-bit support.
+    if (__value < numeric_limits<_To>::min() ||
+        __value > numeric_limits<_To>::max())
+      __throw_format_error("128-bit value is outside of implemented range");
+
+    return __handle_format(static_cast<_To>(__value), __ctx);
+  }
+#endif
+};
+} // namespace __format
+
+// These specializations are helper stubs and not proper formatters.
+// TODO FMT Implement the proper formatter specializations.
+
+// [format.formatter.spec]/2.1 The specializations
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS formatter<char, char>
+    : public __format::__formatter_char<char, char> {};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS formatter<char, wchar_t>
+    : public __format::__formatter_char<char, wchar_t> {};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS formatter<wchar_t, wchar_t>
+    : public __format::__formatter_char<wchar_t, wchar_t> {};
+
+// [format.formatter.spec]/2.2 For each charT, the string type specializations
+
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<_CharT*, _CharT>
+    : public __format::__formatter_c_string<_CharT> {
+  using _Base = __format::__formatter_c_string<_CharT>;
+
+  _LIBCPP_HIDE_FROM_ABI auto format(_CharT* __str, auto& __ctx)
+      -> decltype(__ctx.out()) {
+    _LIBCPP_ASSERT(__str, "The basic_format_arg constructor should have "
+                          "prevented an invalid pointer");
+    return _Base::format(__str, __ctx);
+  }
+};
+
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<const _CharT*, _CharT>
+    : public __format::__formatter_c_string<_CharT> {};
+
+template <class _CharT, size_t _Size>
+struct _LIBCPP_TEMPLATE_VIS formatter<const _CharT[_Size], _CharT>
+    : public __format::__formatter_string<_CharT> {
+  using _Base = __format::__formatter_string<_CharT>;
+
+  _LIBCPP_HIDE_FROM_ABI auto format(const _CharT __str[_Size], auto& __ctx)
+      -> decltype(__ctx.out()) {
+    return _Base::format(_VSTD::basic_string_view<_CharT>(__str, _Size), __ctx);
+  }
+};
+
+template <class _CharT, class _Traits, class _Allocator>
+struct _LIBCPP_TEMPLATE_VIS
+    formatter<basic_string<_CharT, _Traits, _Allocator>, _CharT>
+    : public __format::__formatter_string<_CharT> {
+  using _Base = __format::__formatter_string<_CharT>;
+
+  _LIBCPP_HIDE_FROM_ABI auto
+  format(const basic_string<_CharT, _Traits, _Allocator>& __str, auto& __ctx)
+      -> decltype(__ctx.out()) {
+    return _Base::format(_VSTD::basic_string_view<_CharT>(__str), __ctx);
+  }
+};
+
+template <class _CharT, class _Traits>
+struct _LIBCPP_TEMPLATE_VIS
+    formatter<basic_string_view<_CharT, _Traits>, _CharT>
+    : public __format::__formatter_string<_CharT> {};
+
+// [format.formatter.spec]/2.3
+// For each charT, for each cv-unqualified arithmetic type ArithmeticT other
+// than char, wchar_t, char8_t, char16_t, or char32_t, a specialization
+
+// Boolean.
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<bool, _CharT> {
+  _LIBCPP_HIDE_FROM_ABI
+  auto parse(auto& __parse_ctx) -> decltype(__parse_ctx.begin()) {
+    // TODO FMT Implement
+    return __parse_ctx.begin();
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  auto format(bool __b, auto& __ctx) -> decltype(__ctx.out()) {
+    // TODO FMT Implement using formatting arguments
+    auto __out_it = __ctx.out();
+    *__out_it++ = _CharT('0') + __b;
+    return __out_it;
+  }
+};
+
+// Signed integral types.
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<signed char, _CharT>
+    : public __format::__formatter_arithmetic<signed char, _CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<short, _CharT>
+    : public __format::__formatter_arithmetic<short, _CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<int, _CharT>
+    : public __format::__formatter_arithmetic<int, _CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<long, _CharT>
+    : public __format::__formatter_arithmetic<long, _CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<long long, _CharT>
+    : public __format::__formatter_arithmetic<long long, _CharT> {};
+#ifndef _LIBCPP_HAS_NO_INT128
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<__int128_t, _CharT>
+    : public __format::__formatter_arithmetic<__int128_t, _CharT> {};
+#endif
+
+// Unsigned integral types.
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<unsigned char, _CharT>
+    : public __format::__formatter_arithmetic<unsigned char, _CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<unsigned short, _CharT>
+    : public __format::__formatter_arithmetic<unsigned short, _CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<unsigned, _CharT>
+    : public __format::__formatter_arithmetic<unsigned, _CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<unsigned long, _CharT>
+    : public __format::__formatter_arithmetic<unsigned long, _CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<unsigned long long, _CharT>
+    : public __format::__formatter_arithmetic<unsigned long long, _CharT> {};
+#ifndef _LIBCPP_HAS_NO_INT128
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS formatter<__uint128_t, _CharT>
+    : public __format::__formatter_arithmetic<__uint128_t, _CharT> {};
+#endif
+
+// Floating point types.
+// TODO FMT There are no replacements for the floating point stubs due to not
+// having floating point support in std::to_chars yet. These stubs aren't
+// removed since they are useful for developing the real versions.
+// Ultimately the stubs should be implemented properly and this code can be
+// removed.
+#if 0
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<float, _CharT>
+    : public __format::__formatter_arithmetic<float, _CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<double, _CharT>
+    : public __format::__formatter_arithmetic<double, _CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<long double, _CharT>
+    : public __format::__formatter_arithmetic<long double, _CharT> {};
+#endif
+
+namespace __format {
+
+template <class _CharT, class _ParseCtx, class _Ctx>
+_LIBCPP_HIDE_FROM_ABI const _CharT*
+__handle_replacement_field(const _CharT* __begin, const _CharT* __end,
+                           _ParseCtx& __parse_ctx, _Ctx& __ctx) {
+  __format::__parse_number_result __r =
+      __format::__parse_arg_id(__begin, __end, __parse_ctx);
+
+  switch (*__r.__ptr) {
+  case _CharT(':'):
+    // The arg-id has a format-specifier, advance the input to the format-spec.
+    __parse_ctx.advance_to(__r.__ptr + 1);
+    break;
+  case _CharT('}'):
+    // The arg-id has no format-specifier.
+    __parse_ctx.advance_to(__r.__ptr);
+    break;
+  default:
+    __throw_format_error(
+        "The replacement field arg-id should terminate at a ':' or '}'");
+  }
+
+  _VSTD::visit_format_arg(
+      [&](auto __arg) {
+        if constexpr (same_as<decltype(__arg), monostate>)
+          __throw_format_error("Argument index out of bounds");
+        else {
+          formatter<decltype(__arg), _CharT> __formatter;
+          __parse_ctx.advance_to(__formatter.parse(__parse_ctx));
+          __ctx.advance_to(__formatter.format(__arg, __ctx));
+        }
+      },
+      __ctx.arg(__r.__value));
+
+  __begin = __parse_ctx.begin();
+  if (__begin == __end || *__begin != _CharT('}'))
+    __throw_format_error("The replacement field misses a terminating '}'");
+
+  return ++__begin;
+}
+
+template <class _ParseCtx, class _Ctx>
+_LIBCPP_HIDE_FROM_ABI typename _Ctx::iterator
+__vformat_to(_ParseCtx&& __parse_ctx, _Ctx&& __ctx) {
+  using _CharT = typename _ParseCtx::char_type;
+  static_assert(same_as<typename _Ctx::char_type, _CharT>);
+
+  const _CharT* __begin = __parse_ctx.begin();
+  const _CharT* __end = __parse_ctx.end();
+  typename _Ctx::iterator __out_it = __ctx.out();
+  while (__begin != __end) {
+    switch (*__begin) {
+    case _CharT('{'):
+      ++__begin;
+      if (__begin == __end)
+        __throw_format_error("The format string terminates at a '{'");
+
+      if (*__begin != _CharT('{')) [[likely]] {
+        __ctx.advance_to(_VSTD::move(__out_it));
+        __begin =
+            __handle_replacement_field(__begin, __end, __parse_ctx, __ctx);
+        __out_it = __ctx.out();
+
+        // The output is written and __begin points to the next character. So
+        // start the next iteration.
+        continue;
+      }
+      // The string is an escape character.
+      break;
+
+    case _CharT('}'):
+      ++__begin;
+      if (__begin == __end || *__begin != _CharT('}'))
+        __throw_format_error(
+            "The format string contains an invalid escape sequence");
+
+      break;
+    }
+
+    // Copy the character to the output verbatim.
+    *__out_it++ = *__begin++;
+  }
+  return __out_it;
+}
+
+} // namespace __format
+
+template <class _OutIt, class _CharT>
+requires(output_iterator<_OutIt, const _CharT&>) _LIBCPP_HIDE_FROM_ABI _OutIt
+    __vformat_to(_OutIt __out_it, basic_string_view<_CharT> __fmt,
+                 format_args_t<type_identity_t<_OutIt>, _CharT> __args) {
+  return __format::__vformat_to(
+      basic_format_parse_context{__fmt, __args.__size()},
+      _VSTD::__format_context_create(_VSTD::move(__out_it), __args));
+}
+
+template <output_iterator<const char&> _OutIt>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
+vformat_to(_OutIt __out_it, string_view __fmt,
+           format_args_t<type_identity_t<_OutIt>, char> __args) {
+  return _VSTD::__vformat_to(_VSTD::move(__out_it), __fmt, __args);
+}
+
+template <output_iterator<const wchar_t&> _OutIt>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
+vformat_to(_OutIt __out_it, wstring_view __fmt,
+           format_args_t<type_identity_t<_OutIt>, wchar_t> __args) {
+  return _VSTD::__vformat_to(_VSTD::move(__out_it), __fmt, __args);
+}
+
+template <output_iterator<const char&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
+format_to(_OutIt __out_it, string_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat_to(
+      _VSTD::move(__out_it), __fmt,
+      _VSTD::make_format_args<basic_format_context<_OutIt, char>>(__args...));
+}
+
+template <output_iterator<const wchar_t&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
+format_to(_OutIt __out_it, wstring_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat_to(
+      _VSTD::move(__out_it), __fmt,
+      _VSTD::make_format_args<basic_format_context<_OutIt, wchar_t>>(
+          __args...));
+}
+
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT string
+vformat(string_view __fmt, format_args __args) {
+  string __res;
+  _VSTD::vformat_to(_VSTD::back_inserter(__res), __fmt, __args);
+  return __res;
+}
+
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT wstring
+vformat(wstring_view __fmt, wformat_args __args) {
+  wstring __res;
+  _VSTD::vformat_to(_VSTD::back_inserter(__res), __fmt, __args);
+  return __res;
+}
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT string
+format(string_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat(__fmt, _VSTD::make_format_args(__args...));
+}
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT wstring
+format(wstring_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat(__fmt, _VSTD::make_wformat_args(__args...));
+}
+
+template <class _OutIt>
+struct _LIBCPP_TEMPLATE_VIS format_to_n_result {
+  _OutIt out;
+  iter_difference_t<_OutIt> size;
+};
+
+template <output_iterator<const char&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT format_to_n_result<_OutIt>
+format_to_n(_OutIt __out_it, iter_difference_t<_OutIt> __n, string_view __fmt,
+            const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  string __str = _VSTD::vformat(__fmt, _VSTD::make_format_args(__args...));
+  iter_difference_t<_OutIt> __s = __str.size();
+  iter_difference_t<_OutIt> __m =
+      _VSTD::clamp(__n, iter_difference_t<_OutIt>(0), __s);
+  __out_it = _VSTD::copy_n(__str.begin(), __m, _VSTD::move(__out_it));
+  return {_VSTD::move(__out_it), __s};
+}
+
+template <output_iterator<const wchar_t&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT format_to_n_result<_OutIt>
+format_to_n(_OutIt __out_it, iter_difference_t<_OutIt> __n, wstring_view __fmt,
+            const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  wstring __str = _VSTD::vformat(__fmt, _VSTD::make_wformat_args(__args...));
+  iter_difference_t<_OutIt> __s = __str.size();
+  iter_difference_t<_OutIt> __m =
+      _VSTD::clamp(__n, iter_difference_t<_OutIt>(0), __s);
+  __out_it = _VSTD::copy_n(__str.begin(), __m, _VSTD::move(__out_it));
+  return {_VSTD::move(__out_it), __s};
+}
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT size_t
+formatted_size(string_view __fmt, const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  return _VSTD::vformat(__fmt, _VSTD::make_format_args(__args...)).size();
+}
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT size_t
+formatted_size(wstring_view __fmt, const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  return _VSTD::vformat(__fmt, _VSTD::make_wformat_args(__args...)).size();
+}
+
+#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+
+template <class _OutIt, class _CharT>
+requires(output_iterator<_OutIt, const _CharT&>) _LIBCPP_HIDE_FROM_ABI _OutIt
+    __vformat_to(_OutIt __out_it, locale __loc, basic_string_view<_CharT> __fmt,
+                 format_args_t<type_identity_t<_OutIt>, _CharT> __args) {
+  return __format::__vformat_to(
+      basic_format_parse_context{__fmt, __args.__size()},
+      _VSTD::__format_context_create(_VSTD::move(__out_it), __args,
+                                     _VSTD::move(__loc)));
+}
+
+template <output_iterator<const char&> _OutIt>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
+vformat_to(_OutIt __out_it, locale __loc, string_view __fmt,
+           format_args_t<type_identity_t<_OutIt>, char> __args) {
+  return _VSTD::__vformat_to(_VSTD::move(__out_it), _VSTD::move(__loc), __fmt,
+                             __args);
+}
+
+template <output_iterator<const wchar_t&> _OutIt>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
+vformat_to(_OutIt __out_it, locale __loc, wstring_view __fmt,
+           format_args_t<type_identity_t<_OutIt>, wchar_t> __args) {
+  return _VSTD::__vformat_to(_VSTD::move(__out_it), _VSTD::move(__loc), __fmt,
+                             __args);
+}
+
+template <output_iterator<const char&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt format_to(
+    _OutIt __out_it, locale __loc, string_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat_to(
+      _VSTD::move(__out_it), _VSTD::move(__loc), __fmt,
+      _VSTD::make_format_args<basic_format_context<_OutIt, char>>(__args...));
+}
+
+template <output_iterator<const wchar_t&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt format_to(
+    _OutIt __out_it, locale __loc, wstring_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat_to(
+      _VSTD::move(__out_it), _VSTD::move(__loc), __fmt,
+      _VSTD::make_format_args<basic_format_context<_OutIt, wchar_t>>(
+          __args...));
+}
+
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT string
+vformat(locale __loc, string_view __fmt, format_args __args) {
+  string __res;
+  _VSTD::vformat_to(_VSTD::back_inserter(__res), _VSTD::move(__loc), __fmt,
+                    __args);
+  return __res;
+}
+
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT wstring
+vformat(locale __loc, wstring_view __fmt, wformat_args __args) {
+  wstring __res;
+  _VSTD::vformat_to(_VSTD::back_inserter(__res), _VSTD::move(__loc), __fmt,
+                    __args);
+  return __res;
+}
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT string
+format(locale __loc, string_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat(_VSTD::move(__loc), __fmt,
+                        _VSTD::make_format_args(__args...));
+}
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT wstring
+format(locale __loc, wstring_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat(_VSTD::move(__loc), __fmt,
+                        _VSTD::make_wformat_args(__args...));
+}
+
+template <output_iterator<const char&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT format_to_n_result<_OutIt>
+format_to_n(_OutIt __out_it, iter_difference_t<_OutIt> __n, locale __loc,
+            string_view __fmt, const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  string __str = _VSTD::vformat(_VSTD::move(__loc), __fmt,
+                                _VSTD::make_format_args(__args...));
+  iter_difference_t<_OutIt> __s = __str.size();
+  iter_difference_t<_OutIt> __m =
+      _VSTD::clamp(__n, iter_difference_t<_OutIt>(0), __s);
+  __out_it = _VSTD::copy_n(__str.begin(), __m, _VSTD::move(__out_it));
+  return {_VSTD::move(__out_it), __s};
+}
+
+template <output_iterator<const wchar_t&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT format_to_n_result<_OutIt>
+format_to_n(_OutIt __out_it, iter_difference_t<_OutIt> __n, locale __loc,
+            wstring_view __fmt, const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  wstring __str = _VSTD::vformat(_VSTD::move(__loc), __fmt,
+                                 _VSTD::make_wformat_args(__args...));
+  iter_difference_t<_OutIt> __s = __str.size();
+  iter_difference_t<_OutIt> __m =
+      _VSTD::clamp(__n, iter_difference_t<_OutIt>(0), __s);
+  __out_it = _VSTD::copy_n(__str.begin(), __m, _VSTD::move(__out_it));
+  return {_VSTD::move(__out_it), __s};
+}
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT size_t
+formatted_size(locale __loc, string_view __fmt, const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  return _VSTD::vformat(_VSTD::move(__loc), __fmt,
+                        _VSTD::make_format_args(__args...))
+      .size();
+}
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT size_t
+formatted_size(locale __loc, wstring_view __fmt, const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  return _VSTD::vformat(_VSTD::move(__loc), __fmt,
+                        _VSTD::make_wformat_args(__args...))
+      .size();
+}
+
+#endif // _LIBCPP_HAS_NO_LOCALIZATION
+
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+
+#endif // _LIBCPP_FORMAT
+
+
+====================File: include/list====================
+// -*- C++ -*-
+//===---------------------------- list ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_LIST
+#define _LIBCPP_LIST
+
+/*
+    list synopsis
+
+namespace std
+{
+
+template <class T, class Alloc = allocator<T> >
+class list
+{
+public:
+
+    // types:
+    typedef T value_type;
+    typedef Alloc allocator_type;
+    typedef typename allocator_type::reference reference;
+    typedef typename allocator_type::const_reference const_reference;
+    typedef typename allocator_type::pointer pointer;
+    typedef typename allocator_type::const_pointer const_pointer;
+    typedef implementation-defined iterator;
+    typedef implementation-defined const_iterator;
+    typedef implementation-defined size_type;
+    typedef implementation-defined difference_type;
+    typedef reverse_iterator<iterator> reverse_iterator;
+    typedef reverse_iterator<const_iterator> const_reverse_iterator;
+
+    list()
+        noexcept(is_nothrow_default_constructible<allocator_type>::value);
+    explicit list(const allocator_type& a);
+    explicit list(size_type n);
+    explicit list(size_type n, const allocator_type& a); // C++14
+    list(size_type n, const value_type& value);
+    list(size_type n, const value_type& value, const allocator_type& a);
+    template <class Iter>
+        list(Iter first, Iter last);
+    template <class Iter>
+        list(Iter first, Iter last, const allocator_type& a);
+    list(const list& x);
+    list(const list&, const allocator_type& a);
+    list(list&& x)
+        noexcept(is_nothrow_move_constructible<allocator_type>::value);
+    list(list&&, const allocator_type& a);
+    list(initializer_list<value_type>);
+    list(initializer_list<value_type>, const allocator_type& a);
+
+    ~list();
+
+    list& operator=(const list& x);
+    list& operator=(list&& x)
+        noexcept(
+             allocator_type::propagate_on_container_move_assignment::value &&
+             is_nothrow_move_assignable<allocator_type>::value);
+    list& operator=(initializer_list<value_type>);
+    template <class Iter>
+        void assign(Iter first, Iter last);
+    void assign(size_type n, const value_type& t);
+    void assign(initializer_list<value_type>);
+
+    allocator_type get_allocator() const noexcept;
+
+    iterator begin() noexcept;
+    const_iterator begin() const noexcept;
+    iterator end() noexcept;
+    const_iterator end() const noexcept;
+    reverse_iterator rbegin() noexcept;
+    const_reverse_iterator rbegin() const noexcept;
+    reverse_iterator rend() noexcept;
+    const_reverse_iterator rend() const noexcept;
+    const_iterator cbegin() const noexcept;
+    const_iterator cend() const noexcept;
+    const_reverse_iterator crbegin() const noexcept;
+    const_reverse_iterator crend() const noexcept;
+
+    reference front();
+    const_reference front() const;
+    reference back();
+    const_reference back() const;
+
+    bool empty() const noexcept;
+    size_type size() const noexcept;
+    size_type max_size() const noexcept;
+
+    template <class... Args>
+        reference emplace_front(Args&&... args); // reference in C++17
+    void pop_front();
+    template <class... Args>
+        reference emplace_back(Args&&... args);  // reference in C++17
+    void pop_back();
+    void push_front(const value_type& x);
+    void push_front(value_type&& x);
+    void push_back(const value_type& x);
+    void push_back(value_type&& x);
+    template <class... Args>
+        iterator emplace(const_iterator position, Args&&... args);
+    iterator insert(const_iterator position, const value_type& x);
+    iterator insert(const_iterator position, value_type&& x);
+    iterator insert(const_iterator position, size_type n, const value_type& x);
+    template <class Iter>
+        iterator insert(const_iterator position, Iter first, Iter last);
+    iterator insert(const_iterator position, initializer_list<value_type> il);
+
+    iterator erase(const_iterator position);
+    iterator erase(const_iterator position, const_iterator last);
+
+    void resize(size_type sz);
+    void resize(size_type sz, const value_type& c);
+
+    void swap(list&)
+        noexcept(allocator_traits<allocator_type>::is_always_equal::value);  // C++17
+    void clear() noexcept;
+
+    void splice(const_iterator position, list& x);
+    void splice(const_iterator position, list&& x);
+    void splice(const_iterator position, list& x, const_iterator i);
+    void splice(const_iterator position, list&& x, const_iterator i);
+    void splice(const_iterator position, list& x, const_iterator first,
+                                                  const_iterator last);
+    void splice(const_iterator position, list&& x, const_iterator first,
+                                                  const_iterator last);
+
+    size_type remove(const value_type& value);       // void before C++20
+    template <class Pred>
+      size_type remove_if(Pred pred);                // void before C++20
+    size_type unique();                              // void before C++20
+    template <class BinaryPredicate>
+      size_type unique(BinaryPredicate binary_pred); // void before C++20
+    void merge(list& x);
+    void merge(list&& x);
+    template <class Compare>
+        void merge(list& x, Compare comp);
+    template <class Compare>
+        void merge(list&& x, Compare comp);
+    void sort();
+    template <class Compare>
+        void sort(Compare comp);
+    void reverse() noexcept;
+};
+
+
+template <class InputIterator, class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
+    list(InputIterator, InputIterator, Allocator = Allocator())
+    -> list<typename iterator_traits<InputIterator>::value_type, Allocator>;  // C++17
+
+template <class T, class Alloc>
+    bool operator==(const list<T,Alloc>& x, const list<T,Alloc>& y);
+template <class T, class Alloc>
+    bool operator< (const list<T,Alloc>& x, const list<T,Alloc>& y);
+template <class T, class Alloc>
+    bool operator!=(const list<T,Alloc>& x, const list<T,Alloc>& y);
+template <class T, class Alloc>
+    bool operator> (const list<T,Alloc>& x, const list<T,Alloc>& y);
+template <class T, class Alloc>
+    bool operator>=(const list<T,Alloc>& x, const list<T,Alloc>& y);
+template <class T, class Alloc>
+    bool operator<=(const list<T,Alloc>& x, const list<T,Alloc>& y);
+
+template <class T, class Alloc>
+    void swap(list<T,Alloc>& x, list<T,Alloc>& y)
+         noexcept(noexcept(x.swap(y)));
+
+template <class T, class Allocator, class U>
+    typename list<T, Allocator>::size_type
+    erase(list<T, Allocator>& c, const U& value);       // C++20
+template <class T, class Allocator, class Predicate>
+    typename list<T, Allocator>::size_type
+    erase_if(list<T, Allocator>& c, Predicate pred);    // C++20
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__utility/forward.h>
+#include <algorithm>
+#include <initializer_list>
+#include <iterator>
+#include <limits>
+#include <memory>
+#include <type_traits>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class _VoidPtr> struct __list_node;
+template <class _Tp, class _VoidPtr> struct __list_node_base;
+
+template <class _Tp, class _VoidPtr>
+struct __list_node_pointer_traits {
+  typedef typename __rebind_pointer<_VoidPtr, __list_node<_Tp, _VoidPtr> >::type
+        __node_pointer;
+  typedef typename __rebind_pointer<_VoidPtr, __list_node_base<_Tp, _VoidPtr> >::type
+        __base_pointer;
+
+#if defined(_LIBCPP_ABI_LIST_REMOVE_NODE_POINTER_UB)
+  typedef __base_pointer __link_pointer;
+#else
+  typedef typename conditional<
+          is_pointer<_VoidPtr>::value,
+          __base_pointer,
+          __node_pointer
+  >::type __link_pointer;
+#endif
+
+  typedef typename conditional<
+          is_same<__link_pointer, __node_pointer>::value,
+          __base_pointer,
+          __node_pointer
+  >::type __non_link_pointer;
+
+  static _LIBCPP_INLINE_VISIBILITY
+  __link_pointer __unsafe_link_pointer_cast(__link_pointer __p) {
+      return __p;
+  }
+
+  static _LIBCPP_INLINE_VISIBILITY
+  __link_pointer __unsafe_link_pointer_cast(__non_link_pointer __p) {
+      return static_cast<__link_pointer>(static_cast<_VoidPtr>(__p));
+  }
+
+};
+
+template <class _Tp, class _VoidPtr>
+struct __list_node_base
+{
+    typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
+    typedef typename _NodeTraits::__node_pointer __node_pointer;
+    typedef typename _NodeTraits::__base_pointer __base_pointer;
+    typedef typename _NodeTraits::__link_pointer __link_pointer;
+
+    __link_pointer __prev_;
+    __link_pointer __next_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_node_base() : __prev_(_NodeTraits::__unsafe_link_pointer_cast(__self())),
+                         __next_(_NodeTraits::__unsafe_link_pointer_cast(__self())) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __base_pointer __self() {
+        return pointer_traits<__base_pointer>::pointer_to(*this);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __node_pointer __as_node() {
+        return static_cast<__node_pointer>(__self());
+    }
+};
+
+template <class _Tp, class _VoidPtr>
+struct _LIBCPP_STANDALONE_DEBUG __list_node
+    : public __list_node_base<_Tp, _VoidPtr>
+{
+    _Tp __value_;
+
+    typedef __list_node_base<_Tp, _VoidPtr> __base;
+    typedef typename __base::__link_pointer __link_pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __link_pointer __as_link() {
+        return static_cast<__link_pointer>(__base::__self());
+    }
+};
+
+template <class _Tp, class _Alloc = allocator<_Tp> > class _LIBCPP_TEMPLATE_VIS list;
+template <class _Tp, class _Alloc> class __list_imp;
+template <class _Tp, class _VoidPtr> class _LIBCPP_TEMPLATE_VIS __list_const_iterator;
+
+template <class _Tp, class _VoidPtr>
+class _LIBCPP_TEMPLATE_VIS __list_iterator
+{
+    typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
+    typedef typename _NodeTraits::__link_pointer __link_pointer;
+
+    __link_pointer __ptr_;
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __list_iterator(__link_pointer __p, const void* __c) _NOEXCEPT
+        : __ptr_(__p)
+    {
+        __get_db()->__insert_ic(this, __c);
+    }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __list_iterator(__link_pointer __p) _NOEXCEPT : __ptr_(__p) {}
+#endif
+
+
+
+    template<class, class> friend class list;
+    template<class, class> friend class __list_imp;
+    template<class, class> friend class __list_const_iterator;
+public:
+    typedef bidirectional_iterator_tag       iterator_category;
+    typedef _Tp                              value_type;
+    typedef value_type&                      reference;
+    typedef typename __rebind_pointer<_VoidPtr, value_type>::type pointer;
+    typedef typename pointer_traits<pointer>::difference_type difference_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator() _NOEXCEPT : __ptr_(nullptr)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_i(this);
+#endif
+    }
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator(const __list_iterator& __p)
+        : __ptr_(__p.__ptr_)
+    {
+        __get_db()->__iterator_copy(this, &__p);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~__list_iterator()
+    {
+        __get_db()->__erase_i(this);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator& operator=(const __list_iterator& __p)
+    {
+        if (this != &__p)
+        {
+            __get_db()->__iterator_copy(this, &__p);
+            __ptr_ = __p.__ptr_;
+        }
+        return *this;
+    }
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to dereference a non-dereferenceable list::iterator");
+#endif
+        return __ptr_->__as_node()->__value_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to dereference a non-dereferenceable list::iterator");
+#endif
+        return pointer_traits<pointer>::pointer_to(__ptr_->__as_node()->__value_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator& operator++()
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to increment a non-incrementable list::iterator");
+#endif
+        __ptr_ = __ptr_->__next_;
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator operator++(int) {__list_iterator __t(*this); ++(*this); return __t;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator& operator--()
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__decrementable(this),
+                       "Attempted to decrement a non-decrementable list::iterator");
+#endif
+        __ptr_ = __ptr_->__prev_;
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator operator--(int) {__list_iterator __t(*this); --(*this); return __t;}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __list_iterator& __x, const __list_iterator& __y)
+    {
+        return __x.__ptr_ == __y.__ptr_;
+    }
+    friend _LIBCPP_INLINE_VISIBILITY
+     bool operator!=(const __list_iterator& __x, const __list_iterator& __y)
+        {return !(__x == __y);}
+};
+
+template <class _Tp, class _VoidPtr>
+class _LIBCPP_TEMPLATE_VIS __list_const_iterator
+{
+    typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
+    typedef typename _NodeTraits::__link_pointer __link_pointer;
+
+    __link_pointer __ptr_;
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __list_const_iterator(__link_pointer __p, const void* __c) _NOEXCEPT
+        : __ptr_(__p)
+    {
+        __get_db()->__insert_ic(this, __c);
+    }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __list_const_iterator(__link_pointer __p) _NOEXCEPT : __ptr_(__p) {}
+#endif
+
+    template<class, class> friend class list;
+    template<class, class> friend class __list_imp;
+public:
+    typedef bidirectional_iterator_tag       iterator_category;
+    typedef _Tp                              value_type;
+    typedef const value_type&                reference;
+    typedef typename __rebind_pointer<_VoidPtr, const value_type>::type pointer;
+    typedef typename pointer_traits<pointer>::difference_type difference_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator() _NOEXCEPT : __ptr_(nullptr)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_i(this);
+#endif
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator(const __list_iterator<_Tp, _VoidPtr>& __p) _NOEXCEPT
+        : __ptr_(__p.__ptr_)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__iterator_copy(this, &__p);
+#endif
+    }
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator(const __list_const_iterator& __p)
+        : __ptr_(__p.__ptr_)
+    {
+        __get_db()->__iterator_copy(this, &__p);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~__list_const_iterator()
+    {
+        __get_db()->__erase_i(this);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator& operator=(const __list_const_iterator& __p)
+    {
+        if (this != &__p)
+        {
+            __get_db()->__iterator_copy(this, &__p);
+            __ptr_ = __p.__ptr_;
+        }
+        return *this;
+    }
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to dereference a non-dereferenceable list::const_iterator");
+#endif
+        return __ptr_->__as_node()->__value_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to dereference a non-dereferenceable list::const_iterator");
+#endif
+        return pointer_traits<pointer>::pointer_to(__ptr_->__as_node()->__value_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator& operator++()
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to increment a non-incrementable list::const_iterator");
+#endif
+        __ptr_ = __ptr_->__next_;
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator operator++(int) {__list_const_iterator __t(*this); ++(*this); return __t;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator& operator--()
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__decrementable(this),
+                       "Attempted to decrement a non-decrementable list::const_iterator");
+#endif
+        __ptr_ = __ptr_->__prev_;
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator operator--(int) {__list_const_iterator __t(*this); --(*this); return __t;}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __list_const_iterator& __x, const __list_const_iterator& __y)
+    {
+        return __x.__ptr_ == __y.__ptr_;
+    }
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __list_const_iterator& __x, const __list_const_iterator& __y)
+        {return !(__x == __y);}
+};
+
+template <class _Tp, class _Alloc>
+class __list_imp
+{
+    __list_imp(const __list_imp&);
+    __list_imp& operator=(const __list_imp&);
+public:
+    typedef _Alloc                                                  allocator_type;
+    typedef allocator_traits<allocator_type>                        __alloc_traits;
+    typedef typename __alloc_traits::size_type                      size_type;
+protected:
+    typedef _Tp                                                     value_type;
+    typedef typename __alloc_traits::void_pointer                   __void_pointer;
+    typedef __list_iterator<value_type, __void_pointer>             iterator;
+    typedef __list_const_iterator<value_type, __void_pointer>       const_iterator;
+    typedef __list_node_base<value_type, __void_pointer>            __node_base;
+    typedef __list_node<value_type, __void_pointer>                 __node;
+    typedef typename __rebind_alloc_helper<__alloc_traits, __node>::type __node_allocator;
+    typedef allocator_traits<__node_allocator>                       __node_alloc_traits;
+    typedef typename __node_alloc_traits::pointer                    __node_pointer;
+    typedef typename __node_alloc_traits::pointer                    __node_const_pointer;
+    typedef __list_node_pointer_traits<value_type, __void_pointer> __node_pointer_traits;
+    typedef typename __node_pointer_traits::__link_pointer __link_pointer;
+    typedef __link_pointer __link_const_pointer;
+    typedef typename __alloc_traits::pointer                         pointer;
+    typedef typename __alloc_traits::const_pointer                   const_pointer;
+    typedef typename __alloc_traits::difference_type                 difference_type;
+
+    typedef typename __rebind_alloc_helper<__alloc_traits, __node_base>::type __node_base_allocator;
+    typedef typename allocator_traits<__node_base_allocator>::pointer __node_base_pointer;
+    static_assert((!is_same<allocator_type, __node_allocator>::value),
+                  "internal allocator type must differ from user-specified "
+                  "type; otherwise overload resolution breaks");
+
+    __node_base __end_;
+    __compressed_pair<size_type, __node_allocator> __size_alloc_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __link_pointer __end_as_link() const _NOEXCEPT {
+        return __node_pointer_traits::__unsafe_link_pointer_cast(
+                const_cast<__node_base&>(__end_).__self());
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+          size_type& __sz() _NOEXCEPT {return __size_alloc_.first();}
+    _LIBCPP_INLINE_VISIBILITY
+    const size_type& __sz() const _NOEXCEPT
+        {return __size_alloc_.first();}
+    _LIBCPP_INLINE_VISIBILITY
+          __node_allocator& __node_alloc() _NOEXCEPT
+          {return __size_alloc_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    const __node_allocator& __node_alloc() const _NOEXCEPT
+        {return __size_alloc_.second();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type __node_alloc_max_size() const _NOEXCEPT {
+        return __node_alloc_traits::max_size(__node_alloc());
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    static void __unlink_nodes(__link_pointer __f, __link_pointer __l) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_imp()
+        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    __list_imp(const allocator_type& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    __list_imp(const __node_allocator& __a);
+#ifndef _LIBCPP_CXX03_LANG
+    __list_imp(__node_allocator&& __a) _NOEXCEPT;
+#endif
+    ~__list_imp();
+    void clear() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT {return __sz() == 0;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator begin() _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        return iterator(__end_.__next_, this);
+#else
+        return iterator(__end_.__next_);
+#endif
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const  _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        return const_iterator(__end_.__next_, this);
+#else
+        return const_iterator(__end_.__next_);
+#endif
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    iterator end() _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        return iterator(__end_as_link(), this);
+#else
+        return iterator(__end_as_link());
+#endif
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end() const _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        return const_iterator(__end_as_link(), this);
+#else
+        return const_iterator(__end_as_link());
+#endif
+    }
+
+    void swap(__list_imp& __c)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT;
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<allocator_type>::value);
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __list_imp& __c)
+        {__copy_assign_alloc(__c, integral_constant<bool,
+                      __node_alloc_traits::propagate_on_container_copy_assignment::value>());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__list_imp& __c)
+        _NOEXCEPT_(
+            !__node_alloc_traits::propagate_on_container_move_assignment::value ||
+            is_nothrow_move_assignable<__node_allocator>::value)
+        {__move_assign_alloc(__c, integral_constant<bool,
+                      __node_alloc_traits::propagate_on_container_move_assignment::value>());}
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __list_imp& __c, true_type)
+        {
+            if (__node_alloc() != __c.__node_alloc())
+                clear();
+            __node_alloc() = __c.__node_alloc();
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __list_imp&, false_type)
+        {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__list_imp& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value)
+        {
+            __node_alloc() = _VSTD::move(__c.__node_alloc());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__list_imp&, false_type)
+        _NOEXCEPT
+        {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __invalidate_all_iterators() {
+#if _LIBCPP_DEBUG_LEVEL == 2
+      __get_db()->__invalidate_all(this);
+#endif
+    }
+};
+
+// Unlink nodes [__f, __l]
+template <class _Tp, class _Alloc>
+inline
+void
+__list_imp<_Tp, _Alloc>::__unlink_nodes(__link_pointer __f, __link_pointer __l)
+    _NOEXCEPT
+{
+    __f->__prev_->__next_ = __l->__next_;
+    __l->__next_->__prev_ = __f->__prev_;
+}
+
+template <class _Tp, class _Alloc>
+inline
+__list_imp<_Tp, _Alloc>::__list_imp()
+        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)
+    : __size_alloc_(0, __default_init_tag())
+{
+}
+
+template <class _Tp, class _Alloc>
+inline
+__list_imp<_Tp, _Alloc>::__list_imp(const allocator_type& __a)
+    : __size_alloc_(0, __node_allocator(__a))
+{
+}
+
+template <class _Tp, class _Alloc>
+inline __list_imp<_Tp, _Alloc>::__list_imp(const __node_allocator& __a)
+    : __size_alloc_(0, __a) {}
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp, class _Alloc>
+inline __list_imp<_Tp, _Alloc>::__list_imp(__node_allocator&& __a) _NOEXCEPT
+    : __size_alloc_(0, _VSTD::move(__a)) {}
+#endif
+
+template <class _Tp, class _Alloc>
+__list_imp<_Tp, _Alloc>::~__list_imp() {
+  clear();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__erase_c(this);
+#endif
+}
+
+template <class _Tp, class _Alloc>
+void
+__list_imp<_Tp, _Alloc>::clear() _NOEXCEPT
+{
+    if (!empty())
+    {
+        __node_allocator& __na = __node_alloc();
+        __link_pointer __f = __end_.__next_;
+        __link_pointer __l = __end_as_link();
+        __unlink_nodes(__f, __l->__prev_);
+        __sz() = 0;
+        while (__f != __l)
+        {
+            __node_pointer __np = __f->__as_node();
+            __f = __f->__next_;
+            __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
+            __node_alloc_traits::deallocate(__na, __np, 1);
+        }
+        __invalidate_all_iterators();
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+__list_imp<_Tp, _Alloc>::swap(__list_imp& __c)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<allocator_type>::value)
+#endif
+{
+    _LIBCPP_ASSERT(__alloc_traits::propagate_on_container_swap::value ||
+                   this->__node_alloc() == __c.__node_alloc(),
+                   "list::swap: Either propagate_on_container_swap must be true"
+                   " or the allocators must compare equal");
+    using _VSTD::swap;
+    _VSTD::__swap_allocator(__node_alloc(), __c.__node_alloc());
+    swap(__sz(), __c.__sz());
+    swap(__end_, __c.__end_);
+    if (__sz() == 0)
+        __end_.__next_ = __end_.__prev_ = __end_as_link();
+    else
+        __end_.__prev_->__next_ = __end_.__next_->__prev_ = __end_as_link();
+    if (__c.__sz() == 0)
+        __c.__end_.__next_ = __c.__end_.__prev_ = __c.__end_as_link();
+    else
+        __c.__end_.__prev_->__next_ = __c.__end_.__next_->__prev_ = __c.__end_as_link();
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __libcpp_db* __db = __get_db();
+    __c_node* __cn1 = __db->__find_c_and_lock(this);
+    __c_node* __cn2 = __db->__find_c(&__c);
+    _VSTD::swap(__cn1->beg_, __cn2->beg_);
+    _VSTD::swap(__cn1->end_, __cn2->end_);
+    _VSTD::swap(__cn1->cap_, __cn2->cap_);
+    for (__i_node** __p = __cn1->end_; __p != __cn1->beg_;)
+    {
+        --__p;
+        const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);
+        if (__i->__ptr_ == __c.__end_as_link())
+        {
+            __cn2->__add(*__p);
+            if (--__cn1->end_ != __p)
+                _VSTD::memmove(__p, __p+1, (__cn1->end_ - __p)*sizeof(__i_node*));
+        }
+        else
+            (*__p)->__c_ = __cn1;
+    }
+    for (__i_node** __p = __cn2->end_; __p != __cn2->beg_;)
+    {
+        --__p;
+        const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);
+        if (__i->__ptr_ == __end_as_link())
+        {
+            __cn1->__add(*__p);
+            if (--__cn2->end_ != __p)
+                _VSTD::memmove(__p, __p+1, (__cn2->end_ - __p)*sizeof(__i_node*));
+        }
+        else
+            (*__p)->__c_ = __cn2;
+    }
+    __db->unlock();
+#endif
+}
+
+template <class _Tp, class _Alloc /*= allocator<_Tp>*/>
+class _LIBCPP_TEMPLATE_VIS list
+    : private __list_imp<_Tp, _Alloc>
+{
+    typedef __list_imp<_Tp, _Alloc> base;
+    typedef typename base::__node              __node;
+    typedef typename base::__node_allocator    __node_allocator;
+    typedef typename base::__node_pointer      __node_pointer;
+    typedef typename base::__node_alloc_traits __node_alloc_traits;
+    typedef typename base::__node_base         __node_base;
+    typedef typename base::__node_base_pointer __node_base_pointer;
+    typedef typename base::__link_pointer __link_pointer;
+
+public:
+    typedef _Tp                                      value_type;
+    typedef _Alloc                                   allocator_type;
+    static_assert((is_same<value_type, typename allocator_type::value_type>::value),
+                  "Invalid allocator::value_type");
+    typedef value_type&                              reference;
+    typedef const value_type&                        const_reference;
+    typedef typename base::pointer                   pointer;
+    typedef typename base::const_pointer             const_pointer;
+    typedef typename base::size_type                 size_type;
+    typedef typename base::difference_type           difference_type;
+    typedef typename base::iterator                  iterator;
+    typedef typename base::const_iterator            const_iterator;
+    typedef _VSTD::reverse_iterator<iterator>         reverse_iterator;
+    typedef _VSTD::reverse_iterator<const_iterator>   const_reverse_iterator;
+#if _LIBCPP_STD_VER > 17
+    typedef size_type                                __remove_return_type;
+#else
+    typedef void                                     __remove_return_type;
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    list()
+        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_c(this);
+#endif
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    explicit list(const allocator_type& __a) : base(__a)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_c(this);
+#endif
+    }
+    explicit list(size_type __n);
+#if _LIBCPP_STD_VER > 11
+    explicit list(size_type __n, const allocator_type& __a);
+#endif
+    list(size_type __n, const value_type& __x);
+    list(size_type __n, const value_type& __x, const allocator_type& __a);
+    template <class _InpIter>
+        list(_InpIter __f, _InpIter __l,
+             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type* = 0);
+    template <class _InpIter>
+        list(_InpIter __f, _InpIter __l, const allocator_type& __a,
+             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type* = 0);
+
+    list(const list& __c);
+    list(const list& __c, const __identity_t<allocator_type>& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    list& operator=(const list& __c);
+#ifndef _LIBCPP_CXX03_LANG
+    list(initializer_list<value_type> __il);
+    list(initializer_list<value_type> __il, const allocator_type& __a);
+
+    _LIBCPP_INLINE_VISIBILITY
+    list(list&& __c)
+        _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    list(list&& __c, const __identity_t<allocator_type>& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    list& operator=(list&& __c)
+        _NOEXCEPT_(
+            __node_alloc_traits::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<__node_allocator>::value);
+
+    _LIBCPP_INLINE_VISIBILITY
+    list& operator=(initializer_list<value_type> __il)
+        {assign(__il.begin(), __il.end()); return *this;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void assign(initializer_list<value_type> __il)
+        {assign(__il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+
+    template <class _InpIter>
+        void assign(_InpIter __f, _InpIter __l,
+             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type* = 0);
+    void assign(size_type __n, const value_type& __x);
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT     {return base::__sz();}
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT         {return base::empty();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT
+        {
+            return _VSTD::min<size_type>(
+                base::__node_alloc_max_size(),
+                numeric_limits<difference_type >::max());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+          iterator begin() _NOEXCEPT        {return base::begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin()  const _NOEXCEPT {return base::begin();}
+    _LIBCPP_INLINE_VISIBILITY
+          iterator end() _NOEXCEPT          {return base::end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()    const _NOEXCEPT {return base::end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin() const _NOEXCEPT {return base::begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend()   const _NOEXCEPT {return base::end();}
+
+    _LIBCPP_INLINE_VISIBILITY
+          reverse_iterator rbegin() _NOEXCEPT
+            {return       reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rbegin()  const _NOEXCEPT
+        {return const_reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+          reverse_iterator rend() _NOEXCEPT
+            {return       reverse_iterator(begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rend()    const _NOEXCEPT
+        {return const_reverse_iterator(begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crbegin() const _NOEXCEPT
+        {return const_reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crend()   const _NOEXCEPT
+        {return const_reverse_iterator(begin());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference front()
+    {
+        _LIBCPP_ASSERT(!empty(), "list::front called on empty list");
+        return base::__end_.__next_->__as_node()->__value_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference front() const
+    {
+        _LIBCPP_ASSERT(!empty(), "list::front called on empty list");
+        return base::__end_.__next_->__as_node()->__value_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    reference back()
+    {
+        _LIBCPP_ASSERT(!empty(), "list::back called on empty list");
+        return base::__end_.__prev_->__as_node()->__value_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference back() const
+    {
+        _LIBCPP_ASSERT(!empty(), "list::back called on empty list");
+        return base::__end_.__prev_->__as_node()->__value_;
+    }
+
+#ifndef _LIBCPP_CXX03_LANG
+    void push_front(value_type&& __x);
+    void push_back(value_type&& __x);
+
+    template <class... _Args>
+#if _LIBCPP_STD_VER > 14
+       reference emplace_front(_Args&&... __args);
+#else
+       void      emplace_front(_Args&&... __args);
+#endif
+    template <class... _Args>
+#if _LIBCPP_STD_VER > 14
+        reference emplace_back(_Args&&... __args);
+#else
+       void       emplace_back(_Args&&... __args);
+#endif
+    template <class... _Args>
+        iterator emplace(const_iterator __p, _Args&&... __args);
+
+    iterator insert(const_iterator __p, value_type&& __x);
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, initializer_list<value_type> __il)
+        {return insert(__p, __il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+
+    void push_front(const value_type& __x);
+    void push_back(const value_type& __x);
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _Arg>
+    _LIBCPP_INLINE_VISIBILITY
+    void __emplace_back(_Arg&& __arg) { emplace_back(_VSTD::forward<_Arg>(__arg)); }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    void __emplace_back(value_type const& __arg) { push_back(__arg); }
+#endif
+
+    iterator insert(const_iterator __p, const value_type& __x);
+    iterator insert(const_iterator __p, size_type __n, const value_type& __x);
+    template <class _InpIter>
+        iterator insert(const_iterator __p, _InpIter __f, _InpIter __l,
+             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type* = 0);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(list& __c)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT
+#else
+        _NOEXCEPT_(!__node_alloc_traits::propagate_on_container_swap::value ||
+                   __is_nothrow_swappable<__node_allocator>::value)
+#endif
+        {base::swap(__c);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT {base::clear();}
+
+    void pop_front();
+    void pop_back();
+
+    iterator erase(const_iterator __p);
+    iterator erase(const_iterator __f, const_iterator __l);
+
+    void resize(size_type __n);
+    void resize(size_type __n, const value_type& __x);
+
+    void splice(const_iterator __p, list& __c);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void splice(const_iterator __p, list&& __c) {splice(__p, __c);}
+    _LIBCPP_INLINE_VISIBILITY
+    void splice(const_iterator __p, list&& __c, const_iterator __i)
+        {splice(__p, __c, __i);}
+    _LIBCPP_INLINE_VISIBILITY
+    void splice(const_iterator __p, list&& __c, const_iterator __f, const_iterator __l)
+        {splice(__p, __c, __f, __l);}
+#endif
+    void splice(const_iterator __p, list& __c, const_iterator __i);
+    void splice(const_iterator __p, list& __c, const_iterator __f, const_iterator __l);
+
+    __remove_return_type remove(const value_type& __x);
+    template <class _Pred> __remove_return_type remove_if(_Pred __pred);
+    _LIBCPP_INLINE_VISIBILITY
+    __remove_return_type unique() { return unique(__equal_to<value_type>()); }
+    template <class _BinaryPred>
+        __remove_return_type unique(_BinaryPred __binary_pred);
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(list& __c);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(list&& __c) {merge(__c);}
+
+    template <class _Comp>
+    _LIBCPP_INLINE_VISIBILITY
+        void merge(list&& __c, _Comp __comp) {merge(__c, __comp);}
+#endif
+    template <class _Comp>
+        void merge(list& __c, _Comp __comp);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void sort();
+    template <class _Comp>
+        _LIBCPP_INLINE_VISIBILITY
+        void sort(_Comp __comp);
+
+    void reverse() _NOEXCEPT;
+
+    bool __invariants() const;
+
+    typedef __allocator_destructor<__node_allocator> __node_destructor;
+    typedef unique_ptr<__node, __node_destructor> __hold_pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hold_pointer __allocate_node(__node_allocator& __na) {
+      __node_pointer __p = __node_alloc_traits::allocate(__na, 1);
+      __p->__prev_ = nullptr;
+      return __hold_pointer(__p, __node_destructor(__na, 1));
+    }
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+    bool __dereferenceable(const const_iterator* __i) const;
+    bool __decrementable(const const_iterator* __i) const;
+    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
+    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    static void __link_nodes  (__link_pointer __p, __link_pointer __f, __link_pointer __l);
+    _LIBCPP_INLINE_VISIBILITY
+    void __link_nodes_at_front(__link_pointer __f, __link_pointer __l);
+    _LIBCPP_INLINE_VISIBILITY
+    void __link_nodes_at_back (__link_pointer __f, __link_pointer __l);
+    iterator __iterator(size_type __n);
+    template <class _Comp>
+        static iterator __sort(iterator __f1, iterator __e2, size_type __n, _Comp& __comp);
+
+    void __move_assign(list& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value);
+    void __move_assign(list& __c, false_type);
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator,
+         class _Alloc = allocator<__iter_value_type<_InputIterator>>,
+         class = enable_if_t<__is_allocator<_Alloc>::value>
+         >
+list(_InputIterator, _InputIterator)
+  -> list<__iter_value_type<_InputIterator>, _Alloc>;
+
+template<class _InputIterator,
+         class _Alloc,
+         class = enable_if_t<__is_allocator<_Alloc>::value>
+         >
+list(_InputIterator, _InputIterator, _Alloc)
+  -> list<__iter_value_type<_InputIterator>, _Alloc>;
+#endif
+
+// Link in nodes [__f, __l] just prior to __p
+template <class _Tp, class _Alloc>
+inline
+void
+list<_Tp, _Alloc>::__link_nodes(__link_pointer __p, __link_pointer __f, __link_pointer __l)
+{
+    __p->__prev_->__next_ = __f;
+    __f->__prev_ = __p->__prev_;
+    __p->__prev_ = __l;
+    __l->__next_ = __p;
+}
+
+// Link in nodes [__f, __l] at the front of the list
+template <class _Tp, class _Alloc>
+inline
+void
+list<_Tp, _Alloc>::__link_nodes_at_front(__link_pointer __f, __link_pointer __l)
+{
+    __f->__prev_ = base::__end_as_link();
+    __l->__next_ = base::__end_.__next_;
+    __l->__next_->__prev_ = __l;
+    base::__end_.__next_ = __f;
+}
+
+// Link in nodes [__f, __l] at the back of the list
+template <class _Tp, class _Alloc>
+inline
+void
+list<_Tp, _Alloc>::__link_nodes_at_back(__link_pointer __f, __link_pointer __l)
+{
+    __l->__next_ = base::__end_as_link();
+    __f->__prev_ = base::__end_.__prev_;
+    __f->__prev_->__next_ = __f;
+    base::__end_.__prev_ = __l;
+}
+
+
+template <class _Tp, class _Alloc>
+inline
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::__iterator(size_type __n)
+{
+    return __n <= base::__sz() / 2 ? _VSTD::next(begin(), __n)
+                                   : _VSTD::prev(end(), base::__sz() - __n);
+}
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(size_type __n)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __n > 0; --__n)
+#ifndef _LIBCPP_CXX03_LANG
+        emplace_back();
+#else
+        push_back(value_type());
+#endif
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(size_type __n, const allocator_type& __a) : base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __n > 0; --__n)
+        emplace_back();
+}
+#endif
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(size_type __n, const value_type& __x)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __n > 0; --__n)
+        push_back(__x);
+}
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(size_type __n, const value_type& __x, const allocator_type& __a)
+    : base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __n > 0; --__n)
+        push_back(__x);
+}
+
+template <class _Tp, class _Alloc>
+template <class _InpIter>
+list<_Tp, _Alloc>::list(_InpIter __f, _InpIter __l,
+                        typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type*)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __f != __l; ++__f)
+        __emplace_back(*__f);
+}
+
+template <class _Tp, class _Alloc>
+template <class _InpIter>
+list<_Tp, _Alloc>::list(_InpIter __f, _InpIter __l, const allocator_type& __a,
+                        typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type*)
+    : base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __f != __l; ++__f)
+        __emplace_back(*__f);
+}
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(const list& __c)
+    : base(__node_alloc_traits::select_on_container_copy_construction(
+          __c.__node_alloc())) {
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (const_iterator __i = __c.begin(), __e = __c.end(); __i != __e; ++__i)
+        push_back(*__i);
+}
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(const list& __c, const __identity_t<allocator_type>& __a)
+    : base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (const_iterator __i = __c.begin(), __e = __c.end(); __i != __e; ++__i)
+        push_back(*__i);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(initializer_list<value_type> __il, const allocator_type& __a)
+    : base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (typename initializer_list<value_type>::const_iterator __i = __il.begin(),
+            __e = __il.end(); __i != __e; ++__i)
+        push_back(*__i);
+}
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(initializer_list<value_type> __il)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (typename initializer_list<value_type>::const_iterator __i = __il.begin(),
+            __e = __il.end(); __i != __e; ++__i)
+        push_back(*__i);
+}
+
+template <class _Tp, class _Alloc>
+inline list<_Tp, _Alloc>::list(list&& __c)
+    _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value)
+    : base(_VSTD::move(__c.__node_alloc())) {
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    splice(end(), __c);
+}
+
+template <class _Tp, class _Alloc>
+inline
+list<_Tp, _Alloc>::list(list&& __c, const __identity_t<allocator_type>& __a)
+    : base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    if (__a == __c.get_allocator())
+        splice(end(), __c);
+    else
+    {
+        typedef move_iterator<iterator> _Ip;
+        assign(_Ip(__c.begin()), _Ip(__c.end()));
+    }
+}
+
+template <class _Tp, class _Alloc>
+inline
+list<_Tp, _Alloc>&
+list<_Tp, _Alloc>::operator=(list&& __c)
+        _NOEXCEPT_(
+            __node_alloc_traits::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<__node_allocator>::value)
+{
+    __move_assign(__c, integral_constant<bool,
+          __node_alloc_traits::propagate_on_container_move_assignment::value>());
+    return *this;
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::__move_assign(list& __c, false_type)
+{
+    if (base::__node_alloc() != __c.__node_alloc())
+    {
+        typedef move_iterator<iterator> _Ip;
+        assign(_Ip(__c.begin()), _Ip(__c.end()));
+    }
+    else
+        __move_assign(__c, true_type());
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::__move_assign(list& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value)
+{
+    clear();
+    base::__move_assign_alloc(__c);
+    splice(end(), __c);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+inline
+list<_Tp, _Alloc>&
+list<_Tp, _Alloc>::operator=(const list& __c)
+{
+    if (this != &__c)
+    {
+        base::__copy_assign_alloc(__c);
+        assign(__c.begin(), __c.end());
+    }
+    return *this;
+}
+
+template <class _Tp, class _Alloc>
+template <class _InpIter>
+void
+list<_Tp, _Alloc>::assign(_InpIter __f, _InpIter __l,
+                          typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type*)
+{
+    iterator __i = begin();
+    iterator __e = end();
+    for (; __f != __l && __i != __e; ++__f, (void) ++__i)
+        *__i = *__f;
+    if (__i == __e)
+        insert(__e, __f, __l);
+    else
+        erase(__i, __e);
+#if _LIBCPP_DEBUG_LEVEL == 2
+      __get_db()->__invalidate_all(this);
+#endif
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::assign(size_type __n, const value_type& __x)
+{
+    iterator __i = begin();
+    iterator __e = end();
+    for (; __n > 0 && __i != __e; --__n, (void) ++__i)
+        *__i = __x;
+    if (__i == __e)
+        insert(__e, __n, __x);
+    else
+        erase(__i, __e);
+#if _LIBCPP_DEBUG_LEVEL == 2
+      __get_db()->__invalidate_all(this);
+#endif
+}
+
+template <class _Tp, class _Alloc>
+inline
+_Alloc
+list<_Tp, _Alloc>::get_allocator() const _NOEXCEPT
+{
+    return allocator_type(base::__node_alloc());
+}
+
+template <class _Tp, class _Alloc>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::insert(const_iterator __p, const value_type& __x)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::insert(iterator, x) called with an iterator not"
+        " referring to this list");
+#endif
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+    __link_nodes(__p.__ptr_, __hold->__as_link(), __hold->__as_link());
+    ++base::__sz();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(__hold.release()->__as_link(), this);
+#else
+    return iterator(__hold.release()->__as_link());
+#endif
+}
+
+template <class _Tp, class _Alloc>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::insert(const_iterator __p, size_type __n, const value_type& __x)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::insert(iterator, n, x) called with an iterator not"
+        " referring to this list");
+    iterator __r(__p.__ptr_, this);
+#else
+    iterator __r(__p.__ptr_);
+#endif
+    if (__n > 0)
+    {
+        size_type __ds = 0;
+        __node_allocator& __na = base::__node_alloc();
+        __hold_pointer __hold = __allocate_node(__na);
+        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+        ++__ds;
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __r = iterator(__hold->__as_link(), this);
+#else
+        __r = iterator(__hold->__as_link());
+#endif
+        __hold.release();
+        iterator __e = __r;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (--__n; __n != 0; --__n, (void) ++__e, ++__ds)
+            {
+                __hold.reset(__node_alloc_traits::allocate(__na, 1));
+                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+                __e.__ptr_->__next_ = __hold->__as_link();
+                __hold->__prev_ = __e.__ptr_;
+                __hold.release();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            while (true)
+            {
+                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
+                __link_pointer __prev = __e.__ptr_->__prev_;
+                __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 1);
+                if (__prev == 0)
+                    break;
+#if _LIBCPP_DEBUG_LEVEL == 2
+                __e = iterator(__prev, this);
+#else
+                __e = iterator(__prev);
+#endif
+            }
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __link_nodes(__p.__ptr_, __r.__ptr_, __e.__ptr_);
+        base::__sz() += __ds;
+    }
+    return __r;
+}
+
+template <class _Tp, class _Alloc>
+template <class _InpIter>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::insert(const_iterator __p, _InpIter __f, _InpIter __l,
+             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type*)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::insert(iterator, range) called with an iterator not"
+        " referring to this list");
+    iterator __r(__p.__ptr_, this);
+#else
+    iterator __r(__p.__ptr_);
+#endif
+    if (__f != __l)
+    {
+        size_type __ds = 0;
+        __node_allocator& __na = base::__node_alloc();
+        __hold_pointer __hold = __allocate_node(__na);
+        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), *__f);
+        ++__ds;
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __r = iterator(__hold.get()->__as_link(), this);
+#else
+        __r = iterator(__hold.get()->__as_link());
+#endif
+        __hold.release();
+        iterator __e = __r;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (++__f; __f != __l; ++__f, (void) ++__e, ++__ds)
+            {
+                __hold.reset(__node_alloc_traits::allocate(__na, 1));
+                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), *__f);
+                __e.__ptr_->__next_ = __hold.get()->__as_link();
+                __hold->__prev_ = __e.__ptr_;
+                __hold.release();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            while (true)
+            {
+                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
+                __link_pointer __prev = __e.__ptr_->__prev_;
+                __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 1);
+                if (__prev == 0)
+                    break;
+#if _LIBCPP_DEBUG_LEVEL == 2
+                __e = iterator(__prev, this);
+#else
+                __e = iterator(__prev);
+#endif
+            }
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __link_nodes(__p.__ptr_, __r.__ptr_, __e.__ptr_);
+        base::__sz() += __ds;
+    }
+    return __r;
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::push_front(const value_type& __x)
+{
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+    __link_pointer __nl = __hold->__as_link();
+    __link_nodes_at_front(__nl, __nl);
+    ++base::__sz();
+    __hold.release();
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::push_back(const value_type& __x)
+{
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+    __link_nodes_at_back(__hold.get()->__as_link(), __hold.get()->__as_link());
+    ++base::__sz();
+    __hold.release();
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::push_front(value_type&& __x)
+{
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::move(__x));
+    __link_nodes_at_front(__hold.get()->__as_link(), __hold.get()->__as_link());
+    ++base::__sz();
+    __hold.release();
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::push_back(value_type&& __x)
+{
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::move(__x));
+    __link_nodes_at_back(__hold.get()->__as_link(), __hold.get()->__as_link());
+    ++base::__sz();
+    __hold.release();
+}
+
+template <class _Tp, class _Alloc>
+template <class... _Args>
+#if _LIBCPP_STD_VER > 14
+typename list<_Tp, _Alloc>::reference
+#else
+void
+#endif
+list<_Tp, _Alloc>::emplace_front(_Args&&... __args)
+{
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::forward<_Args>(__args)...);
+    __link_nodes_at_front(__hold.get()->__as_link(), __hold.get()->__as_link());
+    ++base::__sz();
+#if _LIBCPP_STD_VER > 14
+    return __hold.release()->__value_;
+#else
+    __hold.release();
+#endif
+}
+
+template <class _Tp, class _Alloc>
+template <class... _Args>
+#if _LIBCPP_STD_VER > 14
+typename list<_Tp, _Alloc>::reference
+#else
+void
+#endif
+list<_Tp, _Alloc>::emplace_back(_Args&&... __args)
+{
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::forward<_Args>(__args)...);
+    __link_pointer __nl = __hold->__as_link();
+    __link_nodes_at_back(__nl, __nl);
+    ++base::__sz();
+#if _LIBCPP_STD_VER > 14
+    return __hold.release()->__value_;
+#else
+    __hold.release();
+#endif
+}
+
+template <class _Tp, class _Alloc>
+template <class... _Args>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::emplace(const_iterator __p, _Args&&... __args)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::emplace(iterator, args...) called with an iterator not"
+        " referring to this list");
+#endif
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::forward<_Args>(__args)...);
+    __link_pointer __nl = __hold.get()->__as_link();
+    __link_nodes(__p.__ptr_, __nl, __nl);
+    ++base::__sz();
+    __hold.release();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(__nl, this);
+#else
+    return iterator(__nl);
+#endif
+}
+
+template <class _Tp, class _Alloc>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::insert(const_iterator __p, value_type&& __x)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::insert(iterator, x) called with an iterator not"
+        " referring to this list");
+#endif
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::move(__x));
+    __link_pointer __nl = __hold->__as_link();
+    __link_nodes(__p.__ptr_, __nl, __nl);
+    ++base::__sz();
+    __hold.release();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(__nl, this);
+#else
+    return iterator(__nl);
+#endif
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::pop_front()
+{
+    _LIBCPP_ASSERT(!empty(), "list::pop_front() called with empty list");
+    __node_allocator& __na = base::__node_alloc();
+    __link_pointer __n = base::__end_.__next_;
+    base::__unlink_nodes(__n, __n);
+    --base::__sz();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __c_node* __c = __get_db()->__find_c_and_lock(this);
+    for (__i_node** __p = __c->end_; __p != __c->beg_; )
+    {
+        --__p;
+        iterator* __i = static_cast<iterator*>((*__p)->__i_);
+        if (__i->__ptr_ == __n)
+        {
+            (*__p)->__c_ = nullptr;
+            if (--__c->end_ != __p)
+                _VSTD::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
+        }
+    }
+    __get_db()->unlock();
+#endif
+    __node_pointer __np = __n->__as_node();
+    __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
+    __node_alloc_traits::deallocate(__na, __np, 1);
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::pop_back()
+{
+    _LIBCPP_ASSERT(!empty(), "list::pop_back() called on an empty list");
+    __node_allocator& __na = base::__node_alloc();
+    __link_pointer __n = base::__end_.__prev_;
+    base::__unlink_nodes(__n, __n);
+    --base::__sz();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __c_node* __c = __get_db()->__find_c_and_lock(this);
+    for (__i_node** __p = __c->end_; __p != __c->beg_; )
+    {
+        --__p;
+        iterator* __i = static_cast<iterator*>((*__p)->__i_);
+        if (__i->__ptr_ == __n)
+        {
+            (*__p)->__c_ = nullptr;
+            if (--__c->end_ != __p)
+                _VSTD::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
+        }
+    }
+    __get_db()->unlock();
+#endif
+    __node_pointer __np = __n->__as_node();
+    __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
+    __node_alloc_traits::deallocate(__na, __np, 1);
+}
+
+template <class _Tp, class _Alloc>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::erase(const_iterator __p)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::erase(iterator) called with an iterator not"
+        " referring to this list");
+#endif
+    _LIBCPP_ASSERT(__p != end(),
+        "list::erase(iterator) called with a non-dereferenceable iterator");
+    __node_allocator& __na = base::__node_alloc();
+    __link_pointer __n = __p.__ptr_;
+    __link_pointer __r = __n->__next_;
+    base::__unlink_nodes(__n, __n);
+    --base::__sz();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __c_node* __c = __get_db()->__find_c_and_lock(this);
+    for (__i_node** __ip = __c->end_; __ip != __c->beg_; )
+    {
+        --__ip;
+        iterator* __i = static_cast<iterator*>((*__ip)->__i_);
+        if (__i->__ptr_ == __n)
+        {
+            (*__ip)->__c_ = nullptr;
+            if (--__c->end_ != __ip)
+                _VSTD::memmove(__ip, __ip+1, (__c->end_ - __ip)*sizeof(__i_node*));
+        }
+    }
+    __get_db()->unlock();
+#endif
+    __node_pointer __np = __n->__as_node();
+    __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
+    __node_alloc_traits::deallocate(__na, __np, 1);
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(__r, this);
+#else
+    return iterator(__r);
+#endif
+}
+
+template <class _Tp, class _Alloc>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::erase(const_iterator __f, const_iterator __l)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__f) == this,
+        "list::erase(iterator, iterator) called with an iterator not"
+        " referring to this list");
+   _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__l) == this,
+        "list::erase(iterator, iterator) called with an iterator not"
+        " referring to this list");
+#endif
+    if (__f != __l)
+    {
+        __node_allocator& __na = base::__node_alloc();
+        base::__unlink_nodes(__f.__ptr_, __l.__ptr_->__prev_);
+        while (__f != __l)
+        {
+            __link_pointer __n = __f.__ptr_;
+            ++__f;
+            --base::__sz();
+#if _LIBCPP_DEBUG_LEVEL == 2
+            __c_node* __c = __get_db()->__find_c_and_lock(this);
+            for (__i_node** __p = __c->end_; __p != __c->beg_; )
+            {
+                --__p;
+                iterator* __i = static_cast<iterator*>((*__p)->__i_);
+                if (__i->__ptr_ == __n)
+                {
+                    (*__p)->__c_ = nullptr;
+                    if (--__c->end_ != __p)
+                        _VSTD::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
+                }
+            }
+            __get_db()->unlock();
+#endif
+            __node_pointer __np = __n->__as_node();
+            __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
+            __node_alloc_traits::deallocate(__na, __np, 1);
+        }
+    }
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(__l.__ptr_, this);
+#else
+    return iterator(__l.__ptr_);
+#endif
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::resize(size_type __n)
+{
+    if (__n < base::__sz())
+        erase(__iterator(__n), end());
+    else if (__n > base::__sz())
+    {
+        __n -= base::__sz();
+        size_type __ds = 0;
+        __node_allocator& __na = base::__node_alloc();
+        __hold_pointer __hold = __allocate_node(__na);
+        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_));
+        ++__ds;
+#if _LIBCPP_DEBUG_LEVEL == 2
+        iterator __r = iterator(__hold.release()->__as_link(), this);
+#else
+        iterator __r = iterator(__hold.release()->__as_link());
+#endif
+        iterator __e = __r;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (--__n; __n != 0; --__n, (void) ++__e, ++__ds)
+            {
+                __hold.reset(__node_alloc_traits::allocate(__na, 1));
+                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_));
+                __e.__ptr_->__next_ = __hold.get()->__as_link();
+                __hold->__prev_ = __e.__ptr_;
+                __hold.release();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            while (true)
+            {
+                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
+                __link_pointer __prev = __e.__ptr_->__prev_;
+                __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 1);
+                if (__prev == 0)
+                    break;
+#if _LIBCPP_DEBUG_LEVEL == 2
+                __e = iterator(__prev, this);
+#else
+                __e = iterator(__prev);
+#endif
+            }
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __link_nodes_at_back(__r.__ptr_, __e.__ptr_);
+        base::__sz() += __ds;
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::resize(size_type __n, const value_type& __x)
+{
+    if (__n < base::__sz())
+        erase(__iterator(__n), end());
+    else if (__n > base::__sz())
+    {
+        __n -= base::__sz();
+        size_type __ds = 0;
+        __node_allocator& __na = base::__node_alloc();
+        __hold_pointer __hold = __allocate_node(__na);
+        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+        ++__ds;
+        __link_pointer __nl = __hold.release()->__as_link();
+#if _LIBCPP_DEBUG_LEVEL == 2
+        iterator __r = iterator(__nl, this);
+#else
+        iterator __r = iterator(__nl);
+#endif
+        iterator __e = __r;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (--__n; __n != 0; --__n, (void) ++__e, ++__ds)
+            {
+                __hold.reset(__node_alloc_traits::allocate(__na, 1));
+                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+                __e.__ptr_->__next_ = __hold.get()->__as_link();
+                __hold->__prev_ = __e.__ptr_;
+                __hold.release();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            while (true)
+            {
+                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
+                __link_pointer __prev = __e.__ptr_->__prev_;
+                __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 1);
+                if (__prev == 0)
+                    break;
+#if _LIBCPP_DEBUG_LEVEL == 2
+                __e = iterator(__prev, this);
+#else
+                __e = iterator(__prev);
+#endif
+            }
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __link_nodes(base::__end_as_link(), __r.__ptr_, __e.__ptr_);
+        base::__sz() += __ds;
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::splice(const_iterator __p, list& __c)
+{
+    _LIBCPP_ASSERT(this != &__c,
+                   "list::splice(iterator, list) called with this == &list");
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::splice(iterator, list) called with an iterator not"
+        " referring to this list");
+#endif
+    if (!__c.empty())
+    {
+        __link_pointer __f = __c.__end_.__next_;
+        __link_pointer __l = __c.__end_.__prev_;
+        base::__unlink_nodes(__f, __l);
+        __link_nodes(__p.__ptr_, __f, __l);
+        base::__sz() += __c.__sz();
+        __c.__sz() = 0;
+#if _LIBCPP_DEBUG_LEVEL == 2
+        if (&__c != this) {
+            __libcpp_db* __db = __get_db();
+            __c_node* __cn1 = __db->__find_c_and_lock(this);
+            __c_node* __cn2 = __db->__find_c(&__c);
+            for (__i_node** __ip = __cn2->end_; __ip != __cn2->beg_;)
+            {
+                --__ip;
+                iterator* __i = static_cast<iterator*>((*__ip)->__i_);
+                if (__i->__ptr_ != __c.__end_as_link())
+                {
+                    __cn1->__add(*__ip);
+                    (*__ip)->__c_ = __cn1;
+                    if (--__cn2->end_ != __ip)
+                        memmove(__ip, __ip+1, (__cn2->end_ - __ip)*sizeof(__i_node*));
+                }
+            }
+            __db->unlock();
+        }
+#endif
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __i)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::splice(iterator, list, iterator) called with the first iterator"
+        " not referring to this list");
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__i) == &__c,
+        "list::splice(iterator, list, iterator) called with the second iterator"
+        " not referring to the list argument");
+    _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(&__i),
+        "list::splice(iterator, list, iterator) called with the second iterator"
+        " not dereferenceable");
+#endif
+    if (__p.__ptr_ != __i.__ptr_ && __p.__ptr_ != __i.__ptr_->__next_)
+    {
+        __link_pointer __f = __i.__ptr_;
+        base::__unlink_nodes(__f, __f);
+        __link_nodes(__p.__ptr_, __f, __f);
+        --__c.__sz();
+        ++base::__sz();
+#if _LIBCPP_DEBUG_LEVEL == 2
+        if (&__c != this) {
+            __libcpp_db* __db = __get_db();
+            __c_node* __cn1 = __db->__find_c_and_lock(this);
+            __c_node* __cn2 = __db->__find_c(&__c);
+            for (__i_node** __ip = __cn2->end_; __ip != __cn2->beg_;)
+            {
+                --__ip;
+                iterator* __j = static_cast<iterator*>((*__ip)->__i_);
+                if (__j->__ptr_ == __f)
+                {
+                    __cn1->__add(*__ip);
+                    (*__ip)->__c_ = __cn1;
+                    if (--__cn2->end_ != __ip)
+                        _VSTD::memmove(__ip, __ip+1, (__cn2->end_ - __ip)*sizeof(__i_node*));
+                }
+            }
+            __db->unlock();
+        }
+#endif
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __f, const_iterator __l)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::splice(iterator, list, iterator, iterator) called with first iterator not"
+        " referring to this list");
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__f) == &__c,
+        "list::splice(iterator, list, iterator, iterator) called with second iterator not"
+        " referring to the list argument");
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__l) == &__c,
+        "list::splice(iterator, list, iterator, iterator) called with third iterator not"
+        " referring to the list argument");
+    if (this == &__c)
+    {
+        for (const_iterator __i = __f; __i != __l; ++__i)
+            _LIBCPP_ASSERT(__i != __p,
+                           "list::splice(iterator, list, iterator, iterator)"
+                           " called with the first iterator within the range"
+                           " of the second and third iterators");
+    }
+#endif
+    if (__f != __l)
+    {
+        __link_pointer __first = __f.__ptr_;
+        --__l;
+        __link_pointer __last = __l.__ptr_;
+        if (this != &__c)
+        {
+            size_type __s = _VSTD::distance(__f, __l) + 1;
+            __c.__sz() -= __s;
+            base::__sz() += __s;
+        }
+        base::__unlink_nodes(__first, __last);
+        __link_nodes(__p.__ptr_, __first, __last);
+#if _LIBCPP_DEBUG_LEVEL == 2
+        if (&__c != this) {
+            __libcpp_db* __db = __get_db();
+            __c_node* __cn1 = __db->__find_c_and_lock(this);
+            __c_node* __cn2 = __db->__find_c(&__c);
+            for (__i_node** __ip = __cn2->end_; __ip != __cn2->beg_;)
+            {
+                --__ip;
+                iterator* __j = static_cast<iterator*>((*__ip)->__i_);
+                for (__link_pointer __k = __f.__ptr_;
+                                              __k != __l.__ptr_; __k = __k->__next_)
+                {
+                    if (__j->__ptr_ == __k)
+                    {
+                        __cn1->__add(*__ip);
+                        (*__ip)->__c_ = __cn1;
+                        if (--__cn2->end_ != __ip)
+                            _VSTD::memmove(__ip, __ip+1, (__cn2->end_ - __ip)*sizeof(__i_node*));
+                    }
+                }
+            }
+            __db->unlock();
+        }
+#endif
+    }
+}
+
+template <class _Tp, class _Alloc>
+typename list<_Tp, _Alloc>::__remove_return_type
+list<_Tp, _Alloc>::remove(const value_type& __x)
+{
+    list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
+    for (const_iterator __i = begin(), __e = end(); __i != __e;)
+    {
+        if (*__i == __x)
+        {
+            const_iterator __j = _VSTD::next(__i);
+            for (; __j != __e && *__j == __x; ++__j)
+                ;
+            __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
+            __i = __j;
+            if (__i != __e)
+                ++__i;
+        }
+        else
+            ++__i;
+    }
+
+    return (__remove_return_type) __deleted_nodes.size();
+}
+
+template <class _Tp, class _Alloc>
+template <class _Pred>
+typename list<_Tp, _Alloc>::__remove_return_type
+list<_Tp, _Alloc>::remove_if(_Pred __pred)
+{
+    list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
+    for (iterator __i = begin(), __e = end(); __i != __e;)
+    {
+        if (__pred(*__i))
+        {
+            iterator __j = _VSTD::next(__i);
+            for (; __j != __e && __pred(*__j); ++__j)
+                ;
+            __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
+            __i = __j;
+            if (__i != __e)
+                ++__i;
+        }
+        else
+            ++__i;
+    }
+
+    return (__remove_return_type) __deleted_nodes.size();
+}
+
+template <class _Tp, class _Alloc>
+template <class _BinaryPred>
+typename list<_Tp, _Alloc>::__remove_return_type
+list<_Tp, _Alloc>::unique(_BinaryPred __binary_pred)
+{
+    list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
+    for (iterator __i = begin(), __e = end(); __i != __e;)
+    {
+        iterator __j = _VSTD::next(__i);
+        for (; __j != __e && __binary_pred(*__i, *__j); ++__j)
+            ;
+        if (++__i != __j) {
+            __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
+            __i = __j;
+            }
+    }
+
+    return (__remove_return_type) __deleted_nodes.size();
+}
+
+template <class _Tp, class _Alloc>
+inline
+void
+list<_Tp, _Alloc>::merge(list& __c)
+{
+    merge(__c, __less<value_type>());
+}
+
+template <class _Tp, class _Alloc>
+template <class _Comp>
+void
+list<_Tp, _Alloc>::merge(list& __c, _Comp __comp)
+{
+    if (this != _VSTD::addressof(__c))
+    {
+        iterator __f1 = begin();
+        iterator __e1 = end();
+        iterator __f2 = __c.begin();
+        iterator __e2 = __c.end();
+        while (__f1 != __e1 && __f2 != __e2)
+        {
+            if (__comp(*__f2, *__f1))
+            {
+                size_type __ds = 1;
+                iterator __m2 = _VSTD::next(__f2);
+                for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2, (void) ++__ds)
+                    ;
+                base::__sz() += __ds;
+                __c.__sz() -= __ds;
+                __link_pointer __f = __f2.__ptr_;
+                __link_pointer __l = __m2.__ptr_->__prev_;
+                __f2 = __m2;
+                base::__unlink_nodes(__f, __l);
+                __m2 = _VSTD::next(__f1);
+                __link_nodes(__f1.__ptr_, __f, __l);
+                __f1 = __m2;
+            }
+            else
+                ++__f1;
+        }
+        splice(__e1, __c);
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __libcpp_db* __db = __get_db();
+        __c_node* __cn1 = __db->__find_c_and_lock(this);
+        __c_node* __cn2 = __db->__find_c(&__c);
+        for (__i_node** __p = __cn2->end_; __p != __cn2->beg_;)
+        {
+            --__p;
+            iterator* __i = static_cast<iterator*>((*__p)->__i_);
+            if (__i->__ptr_ != __c.__end_as_link())
+            {
+                __cn1->__add(*__p);
+                (*__p)->__c_ = __cn1;
+                if (--__cn2->end_ != __p)
+                    _VSTD::memmove(__p, __p+1, (__cn2->end_ - __p)*sizeof(__i_node*));
+            }
+        }
+        __db->unlock();
+#endif
+    }
+}
+
+template <class _Tp, class _Alloc>
+inline
+void
+list<_Tp, _Alloc>::sort()
+{
+    sort(__less<value_type>());
+}
+
+template <class _Tp, class _Alloc>
+template <class _Comp>
+inline
+void
+list<_Tp, _Alloc>::sort(_Comp __comp)
+{
+    __sort(begin(), end(), base::__sz(), __comp);
+}
+
+template <class _Tp, class _Alloc>
+template <class _Comp>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::__sort(iterator __f1, iterator __e2, size_type __n, _Comp& __comp)
+{
+    switch (__n)
+    {
+    case 0:
+    case 1:
+        return __f1;
+    case 2:
+        if (__comp(*--__e2, *__f1))
+        {
+            __link_pointer __f = __e2.__ptr_;
+            base::__unlink_nodes(__f, __f);
+            __link_nodes(__f1.__ptr_, __f, __f);
+            return __e2;
+        }
+        return __f1;
+    }
+    size_type __n2 = __n / 2;
+    iterator __e1 = _VSTD::next(__f1, __n2);
+    iterator  __r = __f1 = __sort(__f1, __e1, __n2, __comp);
+    iterator __f2 = __e1 = __sort(__e1, __e2, __n - __n2, __comp);
+    if (__comp(*__f2, *__f1))
+    {
+        iterator __m2 = _VSTD::next(__f2);
+        for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2)
+            ;
+        __link_pointer __f = __f2.__ptr_;
+        __link_pointer __l = __m2.__ptr_->__prev_;
+        __r = __f2;
+        __e1 = __f2 = __m2;
+        base::__unlink_nodes(__f, __l);
+        __m2 = _VSTD::next(__f1);
+        __link_nodes(__f1.__ptr_, __f, __l);
+        __f1 = __m2;
+    }
+    else
+        ++__f1;
+    while (__f1 != __e1 && __f2 != __e2)
+    {
+        if (__comp(*__f2, *__f1))
+        {
+            iterator __m2 = _VSTD::next(__f2);
+            for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2)
+                ;
+            __link_pointer __f = __f2.__ptr_;
+            __link_pointer __l = __m2.__ptr_->__prev_;
+            if (__e1 == __f2)
+                __e1 = __m2;
+            __f2 = __m2;
+            base::__unlink_nodes(__f, __l);
+            __m2 = _VSTD::next(__f1);
+            __link_nodes(__f1.__ptr_, __f, __l);
+            __f1 = __m2;
+        }
+        else
+            ++__f1;
+    }
+    return __r;
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::reverse() _NOEXCEPT
+{
+    if (base::__sz() > 1)
+    {
+        iterator __e = end();
+        for (iterator __i = begin(); __i.__ptr_ != __e.__ptr_;)
+        {
+            _VSTD::swap(__i.__ptr_->__prev_, __i.__ptr_->__next_);
+            __i.__ptr_ = __i.__ptr_->__prev_;
+        }
+        _VSTD::swap(__e.__ptr_->__prev_, __e.__ptr_->__next_);
+    }
+}
+
+template <class _Tp, class _Alloc>
+bool
+list<_Tp, _Alloc>::__invariants() const
+{
+    return size() == _VSTD::distance(begin(), end());
+}
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+template <class _Tp, class _Alloc>
+bool
+list<_Tp, _Alloc>::__dereferenceable(const const_iterator* __i) const
+{
+    return __i->__ptr_ != this->__end_as_link();
+}
+
+template <class _Tp, class _Alloc>
+bool
+list<_Tp, _Alloc>::__decrementable(const const_iterator* __i) const
+{
+    return !empty() &&  __i->__ptr_ != base::__end_.__next_;
+}
+
+template <class _Tp, class _Alloc>
+bool
+list<_Tp, _Alloc>::__addable(const const_iterator*, ptrdiff_t) const
+{
+    return false;
+}
+
+template <class _Tp, class _Alloc>
+bool
+list<_Tp, _Alloc>::__subscriptable(const const_iterator*, ptrdiff_t) const
+{
+    return false;
+}
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+{
+    return __x.size() == __y.size() && _VSTD::equal(__x.begin(), __x.end(), __y.begin());
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+{
+    return _VSTD::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+{
+    return __y < __x;
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(list<_Tp, _Alloc>& __x, list<_Tp, _Alloc>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Tp, class _Allocator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY typename list<_Tp, _Allocator>::size_type
+erase_if(list<_Tp, _Allocator>& __c, _Predicate __pred) {
+  return __c.remove_if(__pred);
+}
+
+template <class _Tp, class _Allocator, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY typename list<_Tp, _Allocator>::size_type
+erase(list<_Tp, _Allocator>& __c, const _Up& __v) {
+  return _VSTD::erase_if(__c, [&](auto& __elem) { return __elem == __v; });
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_LIST
+
+
+====================File: include/version====================
+// -*- C++ -*-
+//===--------------------------- version ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_VERSIONH
+#define _LIBCPP_VERSIONH
+
+/*
+  version synopsis
+
+Macro name                                              Value   Headers
+__cpp_lib_addressof_constexpr                           201603L <memory>
+__cpp_lib_allocator_traits_is_always_equal              201411L <deque> <forward_list> <list>
+                                                                <map> <memory> <scoped_allocator>
+                                                                <set> <string> <unordered_map>
+                                                                <unordered_set> <vector>
+__cpp_lib_any                                           201606L <any>
+__cpp_lib_apply                                         201603L <tuple>
+__cpp_lib_array_constexpr                               201811L <array> <iterator>
+                                                        201603L // C++17
+__cpp_lib_as_const                                      201510L <utility>
+__cpp_lib_assume_aligned                                201811L <memory>
+__cpp_lib_atomic_flag_test                              201907L <atomic>
+__cpp_lib_atomic_float                                  201711L <atomic>
+__cpp_lib_atomic_is_always_lock_free                    201603L <atomic>
+__cpp_lib_atomic_lock_free_type_aliases                 201907L <atomic>
+__cpp_lib_atomic_ref                                    201806L <atomic>
+__cpp_lib_atomic_shared_ptr                             201711L <atomic>
+__cpp_lib_atomic_value_initialization                   201911L <atomic> <memory>
+__cpp_lib_atomic_wait                                   201907L <atomic>
+__cpp_lib_barrier                                       201907L <barrier>
+__cpp_lib_bind_front                                    201907L <functional>
+__cpp_lib_bit_cast                                      201806L <bit>
+__cpp_lib_bitops                                        201907L <bit>
+__cpp_lib_bool_constant                                 201505L <type_traits>
+__cpp_lib_bounded_array_traits                          201902L <type_traits>
+__cpp_lib_boyer_moore_searcher                          201603L <functional>
+__cpp_lib_byte                                          201603L <cstddef>
+__cpp_lib_char8_t                                       201907L <atomic> <filesystem> <istream>
+                                                                <limits> <locale> <ostream>
+                                                                <string> <string_view>
+__cpp_lib_chrono                                        201611L <chrono>
+__cpp_lib_chrono_udls                                   201304L <chrono>
+__cpp_lib_clamp                                         201603L <algorithm>
+__cpp_lib_complex_udls                                  201309L <complex>
+__cpp_lib_concepts                                      202002L <concepts>
+__cpp_lib_constexpr_algorithms                          201806L <algorithm>
+__cpp_lib_constexpr_complex                             201711L <complex>
+__cpp_lib_constexpr_dynamic_alloc                       201907L <memory>
+__cpp_lib_constexpr_functional                          201907L <functional>
+__cpp_lib_constexpr_iterator                            201811L <iterator>
+__cpp_lib_constexpr_memory                              201811L <memory>
+__cpp_lib_constexpr_numeric                             201911L <numeric>
+__cpp_lib_constexpr_string                              201811L <string>
+__cpp_lib_constexpr_string_view                         201811L <string_view>
+__cpp_lib_constexpr_tuple                               201811L <tuple>
+__cpp_lib_constexpr_utility                             201811L <utility>
+__cpp_lib_constexpr_vector                              201907L <vector>
+__cpp_lib_coroutine                                     201902L <coroutine>
+__cpp_lib_destroying_delete                             201806L <new>
+__cpp_lib_enable_shared_from_this                       201603L <memory>
+__cpp_lib_endian                                        201907L <bit>
+__cpp_lib_erase_if                                      202002L <deque> <forward_list> <list>
+                                                                <map> <set> <string>
+                                                                <unordered_map> <unordered_set> <vector>
+__cpp_lib_exchange_function                             201304L <utility>
+__cpp_lib_execution                                     201902L <execution>
+                                                        201603L // C++17
+__cpp_lib_filesystem                                    201703L <filesystem>
+__cpp_lib_format                                        201907L <format>
+__cpp_lib_gcd_lcm                                       201606L <numeric>
+__cpp_lib_generic_associative_lookup                    201304L <map> <set>
+__cpp_lib_generic_unordered_lookup                      201811L <unordered_map> <unordered_set>
+__cpp_lib_hardware_interference_size                    201703L <new>
+__cpp_lib_has_unique_object_representations             201606L <type_traits>
+__cpp_lib_hypot                                         201603L <cmath>
+__cpp_lib_incomplete_container_elements                 201505L <forward_list> <list> <vector>
+__cpp_lib_int_pow2                                      202002L <bit>
+__cpp_lib_integer_comparison_functions                  202002L <utility>
+__cpp_lib_integer_sequence                              201304L <utility>
+__cpp_lib_integral_constant_callable                    201304L <type_traits>
+__cpp_lib_interpolate                                   201902L <cmath> <numeric>
+__cpp_lib_invoke                                        201411L <functional>
+__cpp_lib_is_aggregate                                  201703L <type_traits>
+__cpp_lib_is_constant_evaluated                         201811L <type_traits>
+__cpp_lib_is_final                                      201402L <type_traits>
+__cpp_lib_is_invocable                                  201703L <type_traits>
+__cpp_lib_is_layout_compatible                          201907L <type_traits>
+__cpp_lib_is_nothrow_convertible                        201806L <type_traits>
+__cpp_lib_is_null_pointer                               201309L <type_traits>
+__cpp_lib_is_pointer_interconvertible                   201907L <type_traits>
+__cpp_lib_is_scoped_enum                                202011L <type_traits>
+__cpp_lib_is_swappable                                  201603L <type_traits>
+__cpp_lib_jthread                                       201911L <stop_token> <thread>
+__cpp_lib_latch                                         201907L <latch>
+__cpp_lib_launder                                       201606L <new>
+__cpp_lib_list_remove_return_type                       201806L <forward_list> <list>
+__cpp_lib_logical_traits                                201510L <type_traits>
+__cpp_lib_make_from_tuple                               201606L <tuple>
+__cpp_lib_make_reverse_iterator                         201402L <iterator>
+__cpp_lib_make_unique                                   201304L <memory>
+__cpp_lib_map_try_emplace                               201411L <map>
+__cpp_lib_math_constants                                201907L <numbers>
+__cpp_lib_math_special_functions                        201603L <cmath>
+__cpp_lib_memory_resource                               201603L <memory_resource>
+__cpp_lib_node_extract                                  201606L <map> <set> <unordered_map>
+                                                                <unordered_set>
+__cpp_lib_nonmember_container_access                    201411L <array> <deque> <forward_list>
+                                                                <iterator> <list> <map>
+                                                                <regex> <set> <string>
+                                                                <unordered_map> <unordered_set> <vector>
+__cpp_lib_not_fn                                        201603L <functional>
+__cpp_lib_null_iterators                                201304L <iterator>
+__cpp_lib_optional                                      201606L <optional>
+__cpp_lib_parallel_algorithm                            201603L <algorithm> <numeric>
+__cpp_lib_polymorphic_allocator                         201902L <memory>
+__cpp_lib_quoted_string_io                              201304L <iomanip>
+__cpp_lib_ranges                                        201811L <algorithm> <functional> <iterator>
+                                                                <memory> <ranges>
+__cpp_lib_raw_memory_algorithms                         201606L <memory>
+__cpp_lib_remove_cvref                                  201711L <type_traits>
+__cpp_lib_result_of_sfinae                              201210L <functional> <type_traits>
+__cpp_lib_robust_nonmodifying_seq_ops                   201304L <algorithm>
+__cpp_lib_sample                                        201603L <algorithm>
+__cpp_lib_scoped_lock                                   201703L <mutex>
+__cpp_lib_semaphore                                     201907L <semaphore>
+__cpp_lib_shared_mutex                                  201505L <shared_mutex>
+__cpp_lib_shared_ptr_arrays                             201611L <memory>
+__cpp_lib_shared_ptr_weak_type                          201606L <memory>
+__cpp_lib_shared_timed_mutex                            201402L <shared_mutex>
+__cpp_lib_shift                                         201806L <algorithm>
+__cpp_lib_smart_ptr_for_overwrite                       202002L <memory>
+__cpp_lib_source_location                               201907L <source_location>
+__cpp_lib_span                                          202002L <span>
+__cpp_lib_ssize                                         201902L <iterator>
+__cpp_lib_stacktrace                                    202011L <stacktrace>
+__cpp_lib_starts_ends_with                              201711L <string> <string_view>
+__cpp_lib_stdatomic_h                                   202011L <stdatomic.h>
+__cpp_lib_string_contains                               202011L <string> <string_view>
+__cpp_lib_string_udls                                   201304L <string>
+__cpp_lib_string_view                                   201803L <string> <string_view>
+                                                        201606L // C++17
+__cpp_lib_syncbuf                                       201803L <syncstream>
+__cpp_lib_three_way_comparison                          201907L <compare>
+__cpp_lib_to_address                                    201711L <memory>
+__cpp_lib_to_array                                      201907L <array>
+__cpp_lib_to_chars                                      201611L <utility>
+__cpp_lib_to_underlying                                 202102L <utility>
+__cpp_lib_transformation_trait_aliases                  201304L <type_traits>
+__cpp_lib_transparent_operators                         201510L <functional> <memory>
+                                                        201210L // C++14
+__cpp_lib_tuple_element_t                               201402L <tuple>
+__cpp_lib_tuples_by_type                                201304L <tuple> <utility>
+__cpp_lib_type_trait_variable_templates                 201510L <type_traits>
+__cpp_lib_uncaught_exceptions                           201411L <exception>
+__cpp_lib_unordered_map_try_emplace                     201411L <unordered_map>
+__cpp_lib_unwrap_ref                                    201811L <functional>
+__cpp_lib_variant                                       202102L <variant>
+__cpp_lib_void_t                                        201411L <type_traits>
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+// clang-format off
+
+#if _LIBCPP_STD_VER > 11
+# define __cpp_lib_chrono_udls                          201304L
+# define __cpp_lib_complex_udls                         201309L
+# define __cpp_lib_exchange_function                    201304L
+# define __cpp_lib_generic_associative_lookup           201304L
+# define __cpp_lib_integer_sequence                     201304L
+# define __cpp_lib_integral_constant_callable           201304L
+# define __cpp_lib_is_final                             201402L
+# define __cpp_lib_is_null_pointer                      201309L
+# define __cpp_lib_make_reverse_iterator                201402L
+# define __cpp_lib_make_unique                          201304L
+# define __cpp_lib_null_iterators                       201304L
+# define __cpp_lib_quoted_string_io                     201304L
+# define __cpp_lib_result_of_sfinae                     201210L
+# define __cpp_lib_robust_nonmodifying_seq_ops          201304L
+# if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_shared_timed_mutex)
+#   define __cpp_lib_shared_timed_mutex                 201402L
+# endif
+# define __cpp_lib_string_udls                          201304L
+# define __cpp_lib_transformation_trait_aliases         201304L
+# define __cpp_lib_transparent_operators                201210L
+# define __cpp_lib_tuple_element_t                      201402L
+# define __cpp_lib_tuples_by_type                       201304L
+#endif
+
+#if _LIBCPP_STD_VER > 14
+# define __cpp_lib_addressof_constexpr                  201603L
+# define __cpp_lib_allocator_traits_is_always_equal     201411L
+# define __cpp_lib_any                                  201606L
+# define __cpp_lib_apply                                201603L
+# if defined(_MSC_VER) && _MSC_VER >= 1926
+#   define __cpp_lib_array_constexpr                    201803L
+# else
+#   define __cpp_lib_array_constexpr                    201603L
+# endif
+# define __cpp_lib_as_const                             201510L
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+#   define __cpp_lib_atomic_is_always_lock_free         201603L
+# endif
+# define __cpp_lib_bool_constant                        201505L
+// # define __cpp_lib_boyer_moore_searcher                 201603L
+# define __cpp_lib_byte                                 201603L
+# define __cpp_lib_chrono                               201611L
+# define __cpp_lib_clamp                                201603L
+# define __cpp_lib_enable_shared_from_this              201603L
+// # define __cpp_lib_execution                            201603L
+# if !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_filesystem)
+# define __cpp_lib_filesystem                           201703L
+# endif
+# define __cpp_lib_gcd_lcm                              201606L
+// # define __cpp_lib_hardware_interference_size           201703L
+# define __cpp_lib_has_unique_object_representations    201606L
+# define __cpp_lib_hypot                                201603L
+# define __cpp_lib_incomplete_container_elements        201505L
+# define __cpp_lib_invoke                               201411L
+# define __cpp_lib_is_aggregate                         201703L
+# define __cpp_lib_is_invocable                         201703L
+# define __cpp_lib_is_swappable                         201603L
+# define __cpp_lib_launder                              201606L
+# define __cpp_lib_logical_traits                       201510L
+# define __cpp_lib_make_from_tuple                      201606L
+# define __cpp_lib_map_try_emplace                      201411L
+// # define __cpp_lib_math_special_functions               201603L
+// # define __cpp_lib_memory_resource                      201603L
+# define __cpp_lib_node_extract                         201606L
+# define __cpp_lib_nonmember_container_access           201411L
+# define __cpp_lib_not_fn                               201603L
+# define __cpp_lib_optional                             201606L
+// # define __cpp_lib_parallel_algorithm                   201603L
+# define __cpp_lib_raw_memory_algorithms                201606L
+# define __cpp_lib_sample                               201603L
+# define __cpp_lib_scoped_lock                          201703L
+# if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_shared_mutex)
+#   define __cpp_lib_shared_mutex                       201505L
+# endif
+# define __cpp_lib_shared_ptr_arrays                    201611L
+# define __cpp_lib_shared_ptr_weak_type                 201606L
+# if defined(_MSC_VER) && _MSC_VER >= 1926
+#   define __cpp_lib_string_view                        201803L
+# else
+#   define __cpp_lib_string_view                        201606L
+# endif
+// # define __cpp_lib_to_chars                             201611L
+# undef  __cpp_lib_transparent_operators
+# define __cpp_lib_transparent_operators                201510L
+# define __cpp_lib_type_trait_variable_templates        201510L
+# define __cpp_lib_uncaught_exceptions                  201411L
+# define __cpp_lib_unordered_map_try_emplace            201411L
+# define __cpp_lib_variant                              202102L
+# define __cpp_lib_void_t                               201411L
+#endif
+
+#if _LIBCPP_STD_VER > 17
+# undef  __cpp_lib_array_constexpr
+# define __cpp_lib_array_constexpr                      201811L
+// # define __cpp_lib_assume_aligned                       201811L
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+#   define __cpp_lib_atomic_flag_test                   201907L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+// #   define __cpp_lib_atomic_float                       201711L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+#   define __cpp_lib_atomic_lock_free_type_aliases      201907L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+// #   define __cpp_lib_atomic_ref                         201806L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+// #   define __cpp_lib_atomic_shared_ptr                  201711L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+#   define __cpp_lib_atomic_value_initialization        201911L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_atomic_wait)
+#   define __cpp_lib_atomic_wait                        201907L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_barrier)
+#   define __cpp_lib_barrier                            201907L
+# endif
+# define __cpp_lib_bind_front                           201907L
+# define __cpp_lib_bit_cast                             201806L
+// # define __cpp_lib_bitops                               201907L
+# define __cpp_lib_bounded_array_traits                 201902L
+# if !defined(_LIBCPP_HAS_NO_CHAR8_T)
+#   define __cpp_lib_char8_t                            201907L
+# endif
+# define __cpp_lib_concepts                             202002L
+# define __cpp_lib_constexpr_algorithms                 201806L
+// # define __cpp_lib_constexpr_complex                    201711L
+# define __cpp_lib_constexpr_dynamic_alloc              201907L
+# define __cpp_lib_constexpr_functional                 201907L
+# define __cpp_lib_constexpr_iterator                   201811L
+# define __cpp_lib_constexpr_memory                     201811L
+# define __cpp_lib_constexpr_numeric                    201911L
+# define __cpp_lib_constexpr_string                     201811L
+# define __cpp_lib_constexpr_string_view                201811L
+# define __cpp_lib_constexpr_tuple                      201811L
+# define __cpp_lib_constexpr_utility                    201811L
+// # define __cpp_lib_constexpr_vector                     201907L
+// # define __cpp_lib_coroutine                            201902L
+# if _LIBCPP_STD_VER > 17 && defined(__cpp_impl_destroying_delete) && __cpp_impl_destroying_delete >= 201806L
+#   define __cpp_lib_destroying_delete                  201806L
+# endif
+# define __cpp_lib_endian                               201907L
+# define __cpp_lib_erase_if                             202002L
+# undef  __cpp_lib_execution
+// # define __cpp_lib_execution                            201902L
+# if !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
+// #   define __cpp_lib_format                             201907L
+# endif
+# define __cpp_lib_generic_unordered_lookup             201811L
+# define __cpp_lib_int_pow2                             202002L
+# if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+#   define __cpp_lib_integer_comparison_functions       202002L
+# endif
+# define __cpp_lib_interpolate                          201902L
+# define __cpp_lib_is_constant_evaluated                201811L
+// # define __cpp_lib_is_layout_compatible                 201907L
+# define __cpp_lib_is_nothrow_convertible               201806L
+// # define __cpp_lib_is_pointer_interconvertible          201907L
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+// #   define __cpp_lib_jthread                            201911L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_latch)
+#   define __cpp_lib_latch                              201907L
+# endif
+# define __cpp_lib_list_remove_return_type              201806L
+# if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+#   define __cpp_lib_math_constants                     201907L
+# endif
+// # define __cpp_lib_polymorphic_allocator                201902L
+// # define __cpp_lib_ranges                               201811L
+# define __cpp_lib_remove_cvref                         201711L
+# if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_semaphore)
+#   define __cpp_lib_semaphore                          201907L
+# endif
+# define __cpp_lib_shift                                201806L
+// # define __cpp_lib_smart_ptr_for_overwrite              202002L
+// # define __cpp_lib_source_location                      201907L
+# define __cpp_lib_span                                 202002L
+# define __cpp_lib_ssize                                201902L
+# define __cpp_lib_starts_ends_with                     201711L
+# undef  __cpp_lib_string_view
+# define __cpp_lib_string_view                          201803L
+// # define __cpp_lib_syncbuf                              201803L
+// # define __cpp_lib_three_way_comparison                 201907L
+# define __cpp_lib_to_address                           201711L
+# define __cpp_lib_to_array                             201907L
+# define __cpp_lib_unwrap_ref                           201811L
+#endif
+
+#if _LIBCPP_STD_VER > 20
+# define __cpp_lib_is_scoped_enum                       202011L
+// # define __cpp_lib_stacktrace                           202011L
+// # define __cpp_lib_stdatomic_h                          202011L
+# define __cpp_lib_string_contains                      202011L
+# define __cpp_lib_to_underlying                        202102L
+#endif
+
+// clang-format on
+
+#endif // _LIBCPP_VERSIONH
+
+
+====================MIT====================
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+====================NCSA====================
+Legacy LLVM License (https://llvm.org/docs/DeveloperPolicy.html#legacy):
+
+
+====================NCSA====================
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal with
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+    * Redistributions of source code must retain the above copyright notice,
+      this list of conditions and the following disclaimers.
+
+    * Redistributions in binary form must reproduce the above copyright notice,
+      this list of conditions and the following disclaimers in the
+      documentation and/or other materials provided with the distribution.
+
+    * Neither the names of the LLVM Team, University of Illinois at
+      Urbana-Champaign, nor the names of its contributors may be used to
+      endorse or promote products derived from this Software without specific
+      prior written permission.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
+SOFTWARE.
+
+
+====================NCSA====================
+University of Illinois/NCSA
+Open Source License
+
+
+====================NCSA AND MIT====================
+The libc++ library is dual licensed under both the University of Illinois
+"BSD-Like" license and the MIT license.  As a user of this code you may choose
+to use it under either license.  As a contributor, you agree to allow your code
+to be used under both.
+
+Full text of the relevant licenses is included below.
diff --git a/contrib/libs/cxxsupp/libcxx/CREDITS.TXT b/contrib/libs/cxxsupp/libcxx/CREDITS.TXT
new file mode 100644
index 00000000000..597c5fcb7cf
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/CREDITS.TXT
@@ -0,0 +1,167 @@
+This file is a partial list of people who have contributed to the LLVM/libc++
+project.  If you have contributed a patch or made some other contribution to
+LLVM/libc++, please submit a patch to this file to add yourself, and it will be
+done!
+
+The list is sorted by surname and formatted to allow easy grepping and
+beautification by scripts.  The fields are: name (N), email (E), web-address
+(W), PGP key ID and fingerprint (P), description (D), and snail-mail address
+(S).
+
+N: Saleem Abdulrasool
+E: compnerd@compnerd.org
+D: Minor patches and Linux fixes.
+
+N: Muiez Ahmed
+E: muiez@ibm.com
+D: z/OS port.
+
+N: Dan Albert
+E: danalbert@google.com
+D: Android support and test runner improvements.
+
+N: Dimitry Andric
+E: dimitry@andric.com
+D: Visibility fixes, minor FreeBSD portability patches.
+
+N: Holger Arnold
+E: holgerar@gmail.com
+D: Minor fix.
+
+N: David Chisnall
+E: theraven at theravensnest dot org
+D: FreeBSD and Solaris ports, libcxxrt support, some atomics work.
+
+N: Marshall Clow
+E: mclow.lists@gmail.com
+E: marshall@idio.com
+D: C++14 support, patches and bug fixes.
+
+N: Jonathan B Coe
+E: jbcoe@me.com
+D: Implementation of propagate_const.
+
+N: Matthew Dempsky
+E: matthew@dempsky.org
+D: Minor patches and bug fixes.
+
+N: Christopher Di Bella
+E: cjdb@google.com
+E: cjdb.ns@gmail.com
+D: Library concepts.
+
+N: Glen Joseph Fernandes
+E: glenjofe@gmail.com
+D: Implementation of to_address.
+
+N: Eric Fiselier
+E: eric@efcs.ca
+D: LFTS support, patches and bug fixes.
+
+N: Bill Fisher
+E: william.w.fisher@gmail.com
+D: Regex bug fixes.
+
+N: Google Inc.
+D: Copyright owner and contributor of the CityHash algorithm
+
+N: Howard Hinnant
+E: hhinnant@apple.com
+D: Architect and primary author of libc++
+
+N: Sergej Jaskiewicz
+E: jaskiewiczs@icloud.com
+D: Minor improvements in the testing infrastructure
+
+N: Hyeon-bin Jeong
+E: tuhertz@gmail.com
+D: Minor patches and bug fixes.
+
+N: Argyrios Kyrtzidis
+E: kyrtzidis@apple.com
+D: Bug fixes.
+
+N: Bruce Mitchener, Jr.
+E: bruce.mitchener@gmail.com
+D: Emscripten-related changes.
+
+N: Michel Morin
+E: mimomorin@gmail.com
+D: Minor patches to is_convertible.
+
+N: Andrew Morrow
+E: andrew.c.morrow@gmail.com
+D: Minor patches and Linux fixes.
+
+N: Michael Park
+E: mcypark@gmail.com
+D: Implementation of <variant>.
+
+N: Arvid Picciani
+E: aep at exys dot org
+D: Minor patches and musl port.
+
+N: Bjorn Reese
+E: breese@users.sourceforge.net
+D: Initial regex prototype
+
+N: Nico Rieck
+E: nico.rieck@gmail.com
+D: Windows fixes
+
+N: Jon Roelofs
+E: jroelofS@jroelofs.com
+D: Remote testing, Newlib port, baremetal/single-threaded support.
+
+N: Kent Ross
+E: k@mad.cash
+D: Patches for operator<=> support
+
+N: Jonathan Sauer
+D: Minor patches, mostly related to constexpr
+
+N: Craig Silverstein
+E: csilvers@google.com
+D: Implemented Cityhash as the string hash function on 64-bit machines
+
+N: Richard Smith
+D: Minor patches.
+
+N: Joerg Sonnenberger
+E: joerg@NetBSD.org
+D: NetBSD port.
+
+N: Stephan Tolksdorf
+E: st@quanttec.com
+D: Minor <atomic> fix
+
+N: Ruben Van Boxem
+E: vanboxem dot ruben at gmail dot com
+D: Initial Windows patches.
+
+N: Michael van der Westhuizen
+E: r1mikey at gmail dot com
+
+N: Larisse Voufo
+D: Minor patches.
+
+N: Klaas de Vries
+E: klaas at klaasgaaf dot nl
+D: Minor bug fix.
+
+N: Zhang Xiongpang
+E: zhangxiongpang@gmail.com
+D: Minor patches and bug fixes.
+
+N: Xing Xue
+E: xingxue@ca.ibm.com
+D: AIX port
+
+N: Jeffrey Yasskin
+E: jyasskin@gmail.com
+E: jyasskin@google.com
+D: Linux fixes.
+
+N: Zhihao Yuan
+E: lichray@gmail.com
+D: Standard compatibility fixes.
diff --git a/contrib/libs/cxxsupp/libcxx/LICENSE.TXT b/contrib/libs/cxxsupp/libcxx/LICENSE.TXT
new file mode 100644
index 00000000000..e159d283443
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/LICENSE.TXT
@@ -0,0 +1,311 @@
+==============================================================================
+The LLVM Project is under the Apache License v2.0 with LLVM Exceptions:
+==============================================================================
+
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+
+In addition, if you combine or link compiled forms of this Software with
+software that is licensed under the GPLv2 ("Combined Software") and if a
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+
+==============================================================================
+Software from third parties included in the LLVM Project:
+==============================================================================
+The LLVM Project contains third party software which is under different license
+terms. All such code will be identified clearly using at least one of two
+mechanisms:
+1) It will be in a separate directory tree with its own `LICENSE.txt` or
+   `LICENSE` file at the top containing the specific license and restrictions
+   which apply to that software, or
+2) It will contain specific license and restriction terms at the top of every
+   file.
+
+==============================================================================
+Legacy LLVM License (https://llvm.org/docs/DeveloperPolicy.html#legacy):
+==============================================================================
+
+The libc++ library is dual licensed under both the University of Illinois
+"BSD-Like" license and the MIT license.  As a user of this code you may choose
+to use it under either license.  As a contributor, you agree to allow your code
+to be used under both.
+
+Full text of the relevant licenses is included below.
+
+==============================================================================
+
+University of Illinois/NCSA
+Open Source License
+
+Copyright (c) 2009-2019 by the contributors listed in CREDITS.TXT
+
+All rights reserved.
+
+Developed by:
+
+    LLVM Team
+
+    University of Illinois at Urbana-Champaign
+
+    http://llvm.org
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal with
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+    * Redistributions of source code must retain the above copyright notice,
+      this list of conditions and the following disclaimers.
+
+    * Redistributions in binary form must reproduce the above copyright notice,
+      this list of conditions and the following disclaimers in the
+      documentation and/or other materials provided with the distribution.
+
+    * Neither the names of the LLVM Team, University of Illinois at
+      Urbana-Champaign, nor the names of its contributors may be used to
+      endorse or promote products derived from this Software without specific
+      prior written permission.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
+SOFTWARE.
+
+==============================================================================
+
+Copyright (c) 2009-2014 by the contributors listed in CREDITS.TXT
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/contrib/libs/cxxsupp/libcxx/glibcxx_eh_cxx17.cpp b/contrib/libs/cxxsupp/libcxx/glibcxx_eh_cxx17.cpp
new file mode 100644
index 00000000000..5e5ad083ba9
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/glibcxx_eh_cxx17.cpp
@@ -0,0 +1,17 @@
+#include <cxxabi.h>
+
+/**
+ * libc++ expects std::uncaught_exceptions() to be provided by C++ runtime library.
+ *
+ * GCC versions prior to GCC 6 did not provide this function yet, but it can be
+ * implemented using its API.
+ *
+ * This implementation should cover ubuntu-12, ubuntu-14, ubuntu-16.
+ */
+
+namespace std {
+    int uncaught_exceptions() noexcept {
+        const auto* globals{__cxxabiv1::__cxa_get_globals()};
+        return static_cast<int>(globals->uncaughtExceptions);
+    }
+}
diff --git a/contrib/libs/cxxsupp/libcxx/import b/contrib/libs/cxxsupp/libcxx/import
new file mode 100755
index 00000000000..9b93145897b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/import
@@ -0,0 +1,22 @@
+#!/bin/sh -e
+
+rev=968e2739
+output_dir="libcxx-r$rev"
+if [ -z $1 ] ; then
+    git clone https://github.com/llvm/llvm-project.git --no-checkout "$output_dir/tmp"
+else
+    git clone --local --no-checkout $1 "$output_dir/tmp"
+fi
+cd "$output_dir/tmp"
+git checkout "$rev"
+cp -R libcxx/include ../include
+cp -R libcxx/src ../src
+cp libcxx/.clang-format ../.clang-format
+cp libcxx/CREDITS.TXT ../CREDITS.TXT
+cp libcxx/LICENSE.TXT ../LICENSE.TXT
+cd ..
+rm -rf tmp
+rm src/CMakeLists.txt include/CMakeLists.txt
+
+# Fix tabs and trailing spaces
+find -type f | xargs sed -e 's/\t/    /g' -e 's/ *$//' -i
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/adjacent_find.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/adjacent_find.h
new file mode 100644
index 00000000000..621ef5f20f8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/adjacent_find.h
@@ -0,0 +1,46 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_ADJACENT_FIND_H
+#define _LIBCPP___ALGORITHM_ADJACENT_FIND_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred) {
+  if (__first != __last) {
+    _ForwardIterator __i = __first;
+    while (++__i != __last) {
+      if (__pred(*__first, *__i))
+        return __first;
+      __first = __i;
+    }
+  }
+  return __last;
+}
+
+template <class _ForwardIterator>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+adjacent_find(_ForwardIterator __first, _ForwardIterator __last) {
+  typedef typename iterator_traits<_ForwardIterator>::value_type __v;
+  return _VSTD::adjacent_find(__first, __last, __equal_to<__v>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_ADJACENT_FIND_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/all_of.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/all_of.h
new file mode 100644
index 00000000000..817a4bc89ca
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/all_of.h
@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_ALL_OF_H
+#define _LIBCPP___ALGORITHM_ALL_OF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
+  for (; __first != __last; ++__first)
+    if (!__pred(*__first))
+      return false;
+  return true;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_ALL_OF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/any_of.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/any_of.h
new file mode 100644
index 00000000000..f4116d91305
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/any_of.h
@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_ANY_OF_H
+#define _LIBCPP___ALGORITHM_ANY_OF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
+  for (; __first != __last; ++__first)
+    if (__pred(*__first))
+      return true;
+  return false;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_ANY_OF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/binary_search.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/binary_search.h
new file mode 100644
index 00000000000..cd1d7b1a752
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/binary_search.h
@@ -0,0 +1,55 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_BINARY_SEARCH_H
+#define _LIBCPP___ALGORITHM_BINARY_SEARCH_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/lower_bound.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+__binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+    __first = _VSTD::__lower_bound<_Compare>(__first, __last, __value_, __comp);
+    return __first != __last && !__comp(__value_, *__first);
+}
+
+template <class _ForwardIterator, class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    return _VSTD::__binary_search<_Comp_ref>(__first, __last, __value_, __comp);
+}
+
+template <class _ForwardIterator, class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
+{
+    return _VSTD::binary_search(__first, __last, __value_,
+                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_BINARY_SEARCH_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/clamp.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/clamp.h
new file mode 100644
index 00000000000..db28735e97a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/clamp.h
@@ -0,0 +1,46 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_CLAMP_H
+#define _LIBCPP___ALGORITHM_CLAMP_H
+
+#include <__config>
+#include <__debug>
+#include <__algorithm/comp.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+template<class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+const _Tp&
+clamp(const _Tp& __v, const _Tp& __lo, const _Tp& __hi, _Compare __comp)
+{
+    _LIBCPP_ASSERT(!__comp(__hi, __lo), "Bad bounds passed to std::clamp");
+    return __comp(__v, __lo) ? __lo : __comp(__hi, __v) ? __hi : __v;
+
+}
+
+template<class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+const _Tp&
+clamp(const _Tp& __v, const _Tp& __lo, const _Tp& __hi)
+{
+    return _VSTD::clamp(__v, __lo, __hi, __less<_Tp>());
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_CLAMP_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/comp.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/comp.h
new file mode 100644
index 00000000000..b3f971e4f05
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/comp.h
@@ -0,0 +1,92 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COMP_H
+#define _LIBCPP___ALGORITHM_COMP_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// I'd like to replace these with _VSTD::equal_to<void>, but can't because:
+//   * That only works with C++14 and later, and
+//   * We haven't included <functional> here.
+template <class _T1, class _T2 = _T1>
+struct __equal_to
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 bool operator()(const _T1& __x, const _T2& __y) const {return __x == __y;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 bool operator()(const _T2& __x, const _T1& __y) const {return __x == __y;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 bool operator()(const _T2& __x, const _T2& __y) const {return __x == __y;}
+};
+
+template <class _T1>
+struct __equal_to<_T1, _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
+};
+
+template <class _T1>
+struct __equal_to<const _T1, _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
+};
+
+template <class _T1>
+struct __equal_to<_T1, const _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
+};
+
+template <class _T1, class _T2 = _T1>
+struct __less
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _T1& __x, const _T2& __y) const {return __x < __y;}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _T2& __x, const _T1& __y) const {return __x < __y;}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _T2& __x, const _T2& __y) const {return __x < __y;}
+};
+
+template <class _T1>
+struct __less<_T1, _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
+};
+
+template <class _T1>
+struct __less<const _T1, _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
+};
+
+template <class _T1>
+struct __less<_T1, const _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COMP_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/comp_ref_type.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/comp_ref_type.h
new file mode 100644
index 00000000000..a3a3866f14d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/comp_ref_type.h
@@ -0,0 +1,80 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COMP_REF_TYPE_H
+#define _LIBCPP___ALGORITHM_COMP_REF_TYPE_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifdef _LIBCPP_DEBUG
+
+template <class _Compare>
+struct __debug_less
+{
+    _Compare &__comp_;
+    _LIBCPP_CONSTEXPR_AFTER_CXX17
+    __debug_less(_Compare& __c) : __comp_(__c) {}
+
+    template <class _Tp, class _Up>
+    _LIBCPP_CONSTEXPR_AFTER_CXX17
+    bool operator()(const _Tp& __x,  const _Up& __y)
+    {
+        bool __r = __comp_(__x, __y);
+        if (__r)
+            __do_compare_assert(0, __y, __x);
+        return __r;
+    }
+
+    template <class _Tp, class _Up>
+    _LIBCPP_CONSTEXPR_AFTER_CXX17
+    bool operator()(_Tp& __x,  _Up& __y)
+    {
+        bool __r = __comp_(__x, __y);
+        if (__r)
+            __do_compare_assert(0, __y, __x);
+        return __r;
+    }
+
+    template <class _LHS, class _RHS>
+    _LIBCPP_CONSTEXPR_AFTER_CXX17
+    inline _LIBCPP_INLINE_VISIBILITY
+    decltype((void)declval<_Compare&>()(
+        declval<_LHS const&>(), declval<_RHS const&>()))
+    __do_compare_assert(int, _LHS & __l, _RHS & __r) {
+        _LIBCPP_ASSERT(!__comp_(__l, __r),
+            "Comparator does not induce a strict weak ordering");
+    }
+
+    template <class _LHS, class _RHS>
+    _LIBCPP_CONSTEXPR_AFTER_CXX17
+    inline _LIBCPP_INLINE_VISIBILITY
+    void __do_compare_assert(long, _LHS &, _RHS &) {}
+};
+
+#endif // _LIBCPP_DEBUG
+
+template <class _Comp>
+struct __comp_ref_type {
+  // Pass the comparator by lvalue reference. Or in debug mode, using a
+  // debugging wrapper that stores a reference.
+#ifndef _LIBCPP_DEBUG
+  typedef _Comp& type;
+#else
+  typedef __debug_less<_Comp> type;
+#endif
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COMP_REF_TYPE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/copy.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/copy.h
new file mode 100644
index 00000000000..e7e8b9e51a3
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/copy.h
@@ -0,0 +1,77 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COPY_H
+#define _LIBCPP___ALGORITHM_COPY_H
+
+#include <__config>
+#include <__algorithm/unwrap_iter.h>
+#include <__iterator/iterator_traits.h>
+#include <cstring>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// copy
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+__copy_constexpr(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    for (; __first != __last; ++__first, (void) ++__result)
+        *__result = *__first;
+    return __result;
+}
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+__copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    return _VSTD::__copy_constexpr(__first, __last, __result);
+}
+
+template <class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_same<typename remove_const<_Tp>::type, _Up>::value &&
+    is_trivially_copy_assignable<_Up>::value,
+    _Up*
+>::type
+__copy(_Tp* __first, _Tp* __last, _Up* __result)
+{
+    const size_t __n = static_cast<size_t>(__last - __first);
+    if (__n > 0)
+        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
+    return __result + __n;
+}
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    if (__libcpp_is_constant_evaluated()) {
+        return _VSTD::__copy_constexpr(__first, __last, __result);
+    } else {
+        return _VSTD::__rewrap_iter(__result,
+            _VSTD::__copy(_VSTD::__unwrap_iter(__first),
+                          _VSTD::__unwrap_iter(__last),
+                          _VSTD::__unwrap_iter(__result)));
+    }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COPY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/copy_backward.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/copy_backward.h
new file mode 100644
index 00000000000..4a2f8c0c49c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/copy_backward.h
@@ -0,0 +1,79 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COPY_BACKWARD_H
+#define _LIBCPP___ALGORITHM_COPY_BACKWARD_H
+
+#include <__config>
+#include <__algorithm/unwrap_iter.h>
+#include <__iterator/iterator_traits.h>
+#include <cstring>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _BidirectionalIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+__copy_backward_constexpr(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
+{
+    while (__first != __last)
+        *--__result = *--__last;
+    return __result;
+}
+
+template <class _BidirectionalIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+__copy_backward(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
+{
+    return _VSTD::__copy_backward_constexpr(__first, __last, __result);
+}
+
+template <class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_same<typename remove_const<_Tp>::type, _Up>::value &&
+    is_trivially_copy_assignable<_Up>::value,
+    _Up*
+>::type
+__copy_backward(_Tp* __first, _Tp* __last, _Up* __result)
+{
+    const size_t __n = static_cast<size_t>(__last - __first);
+    if (__n > 0)
+    {
+        __result -= __n;
+        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
+    }
+    return __result;
+}
+
+template <class _BidirectionalIterator1, class _BidirectionalIterator2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_BidirectionalIterator2
+copy_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
+              _BidirectionalIterator2 __result)
+{
+    if (__libcpp_is_constant_evaluated()) {
+        return _VSTD::__copy_backward_constexpr(__first, __last, __result);
+    } else {
+        return _VSTD::__rewrap_iter(__result,
+            _VSTD::__copy_backward(_VSTD::__unwrap_iter(__first),
+                                   _VSTD::__unwrap_iter(__last),
+                                   _VSTD::__unwrap_iter(__result)));
+    }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COPY_BACKWARD_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/copy_if.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/copy_if.h
new file mode 100644
index 00000000000..230826f63af
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/copy_if.h
@@ -0,0 +1,43 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COPY_IF_H
+#define _LIBCPP___ALGORITHM_COPY_IF_H
+
+#include <__config>
+#include <__algorithm/unwrap_iter.h>
+#include <__iterator/iterator_traits.h>
+#include <cstring>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _InputIterator, class _OutputIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+copy_if(_InputIterator __first, _InputIterator __last,
+        _OutputIterator __result, _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+    {
+        if (__pred(*__first))
+        {
+            *__result = *__first;
+            ++__result;
+        }
+    }
+    return __result;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COPY_IF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/copy_n.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/copy_n.h
new file mode 100644
index 00000000000..6417a0543e5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/copy_n.h
@@ -0,0 +1,67 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COPY_N_H
+#define _LIBCPP___ALGORITHM_COPY_N_H
+
+#include <__config>
+#include <__algorithm/copy.h>
+#include <__algorithm/unwrap_iter.h>
+#include <__iterator/iterator_traits.h>
+#include <cstring>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _InputIterator, class _Size, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+typename enable_if
+<
+    __is_cpp17_input_iterator<_InputIterator>::value &&
+   !__is_cpp17_random_access_iterator<_InputIterator>::value,
+    _OutputIterator
+>::type
+copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
+{
+    typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize;
+    _IntegralSize __n = __orig_n;
+    if (__n > 0)
+    {
+        *__result = *__first;
+        ++__result;
+        for (--__n; __n > 0; --__n)
+        {
+            ++__first;
+            *__result = *__first;
+            ++__result;
+        }
+    }
+    return __result;
+}
+
+template<class _InputIterator, class _Size, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+typename enable_if
+<
+    __is_cpp17_random_access_iterator<_InputIterator>::value,
+    _OutputIterator
+>::type
+copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
+{
+    typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize;
+    _IntegralSize __n = __orig_n;
+    return _VSTD::copy(__first, __first + __n, __result);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COPY_N_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/count.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/count.h
new file mode 100644
index 00000000000..81a2c186f83
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/count.h
@@ -0,0 +1,35 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COUNT_H
+#define _LIBCPP___ALGORITHM_COUNT_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Tp>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    typename iterator_traits<_InputIterator>::difference_type
+    count(_InputIterator __first, _InputIterator __last, const _Tp& __value_) {
+  typename iterator_traits<_InputIterator>::difference_type __r(0);
+  for (; __first != __last; ++__first)
+    if (*__first == __value_)
+      ++__r;
+  return __r;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COUNT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/count_if.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/count_if.h
new file mode 100644
index 00000000000..00f5d671da5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/count_if.h
@@ -0,0 +1,35 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COUNT_IF_H
+#define _LIBCPP___ALGORITHM_COUNT_IF_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    typename iterator_traits<_InputIterator>::difference_type
+    count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
+  typename iterator_traits<_InputIterator>::difference_type __r(0);
+  for (; __first != __last; ++__first)
+    if (__pred(*__first))
+      ++__r;
+  return __r;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COUNT_IF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/equal.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/equal.h
new file mode 100644
index 00000000000..0fe1a21fe52
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/equal.h
@@ -0,0 +1,85 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_EQUAL_H
+#define _LIBCPP___ALGORITHM_EQUAL_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred) {
+  for (; __first1 != __last1; ++__first1, (void)++__first2)
+    if (!__pred(*__first1, *__first2))
+      return false;
+  return true;
+}
+
+template <class _InputIterator1, class _InputIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2) {
+  typedef typename iterator_traits<_InputIterator1>::value_type __v1;
+  typedef typename iterator_traits<_InputIterator2>::value_type __v2;
+  return _VSTD::equal(__first1, __last1, __first2, __equal_to<__v1, __v2>());
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _BinaryPredicate, class _InputIterator1, class _InputIterator2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+__equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
+        _BinaryPredicate __pred, input_iterator_tag, input_iterator_tag) {
+  for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void)++__first2)
+    if (!__pred(*__first1, *__first2))
+      return false;
+  return __first1 == __last1 && __first2 == __last2;
+}
+
+template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+__equal(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+        _RandomAccessIterator2 __last2, _BinaryPredicate __pred, random_access_iterator_tag,
+        random_access_iterator_tag) {
+  if (_VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
+    return false;
+  return _VSTD::equal<_RandomAccessIterator1, _RandomAccessIterator2,
+                      _BinaryPredicate&>(__first1, __last1, __first2, __pred);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
+      _BinaryPredicate __pred) {
+  return _VSTD::__equal<_BinaryPredicate&>(
+      __first1, __last1, __first2, __last2, __pred, typename iterator_traits<_InputIterator1>::iterator_category(),
+      typename iterator_traits<_InputIterator2>::iterator_category());
+}
+
+template <class _InputIterator1, class _InputIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) {
+  typedef typename iterator_traits<_InputIterator1>::value_type __v1;
+  typedef typename iterator_traits<_InputIterator2>::value_type __v2;
+  return _VSTD::__equal(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>(),
+                        typename iterator_traits<_InputIterator1>::iterator_category(),
+                        typename iterator_traits<_InputIterator2>::iterator_category());
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_EQUAL_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/equal_range.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/equal_range.h
new file mode 100644
index 00000000000..679456e27b4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/equal_range.h
@@ -0,0 +1,82 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_EQUAL_RANGE_H
+#define _LIBCPP___ALGORITHM_EQUAL_RANGE_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/half_positive.h>
+#include <__algorithm/lower_bound.h>
+#include <__algorithm/upper_bound.h>
+#include <iterator>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _ForwardIterator, class _Tp>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 pair<_ForwardIterator, _ForwardIterator>
+__equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
+    difference_type __len = _VSTD::distance(__first, __last);
+    while (__len != 0)
+    {
+        difference_type __l2 = _VSTD::__half_positive(__len);
+        _ForwardIterator __m = __first;
+        _VSTD::advance(__m, __l2);
+        if (__comp(*__m, __value_))
+        {
+            __first = ++__m;
+            __len -= __l2 + 1;
+        }
+        else if (__comp(__value_, *__m))
+        {
+            __last = __m;
+            __len = __l2;
+        }
+        else
+        {
+            _ForwardIterator __mp1 = __m;
+            return pair<_ForwardIterator, _ForwardIterator>
+                   (
+                      _VSTD::__lower_bound<_Compare>(__first, __m, __value_, __comp),
+                      _VSTD::__upper_bound<_Compare>(++__mp1, __last, __value_, __comp)
+                   );
+        }
+    }
+    return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
+}
+
+template <class _ForwardIterator, class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+pair<_ForwardIterator, _ForwardIterator>
+equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    return _VSTD::__equal_range<_Comp_ref>(__first, __last, __value_, __comp);
+}
+
+template <class _ForwardIterator, class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+pair<_ForwardIterator, _ForwardIterator>
+equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
+{
+    return _VSTD::equal_range(__first, __last, __value_,
+                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_EQUAL_RANGE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/fill.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/fill.h
new file mode 100644
index 00000000000..1fad1de993b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/fill.h
@@ -0,0 +1,50 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FILL_H
+#define _LIBCPP___ALGORITHM_FILL_H
+
+#include <__config>
+#include <__algorithm/fill_n.h>
+#include <__iterator/iterator_traits.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+__fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, forward_iterator_tag)
+{
+    for (; __first != __last; ++__first)
+        *__first = __value_;
+}
+
+template <class _RandomAccessIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+__fill(_RandomAccessIterator __first, _RandomAccessIterator __last, const _Tp& __value_, random_access_iterator_tag)
+{
+    _VSTD::fill_n(__first, __last - __first, __value_);
+}
+
+template <class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
+{
+    _VSTD::__fill(__first, __last, __value_, typename iterator_traits<_ForwardIterator>::iterator_category());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FILL_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/fill_n.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/fill_n.h
new file mode 100644
index 00000000000..857ac141573
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/fill_n.h
@@ -0,0 +1,42 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FILL_N_H
+#define _LIBCPP___ALGORITHM_FILL_N_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _OutputIterator, class _Size, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+__fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
+{
+    for (; __n > 0; ++__first, (void) --__n)
+        *__first = __value_;
+    return __first;
+}
+
+template <class _OutputIterator, class _Size, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
+{
+   return _VSTD::__fill_n(__first, _VSTD::__convert_to_integral(__n), __value_);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FILL_N_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/find.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/find.h
new file mode 100644
index 00000000000..2a6dfbe41a9
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/find.h
@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FIND_H
+#define _LIBCPP___ALGORITHM_FIND_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Tp>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _InputIterator
+find(_InputIterator __first, _InputIterator __last, const _Tp& __value_) {
+  for (; __first != __last; ++__first)
+    if (*__first == __value_)
+      break;
+  return __first;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FIND_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/find_end.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/find_end.h
new file mode 100644
index 00000000000..95ac2199fd3
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/find_end.h
@@ -0,0 +1,148 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FIND_END_OF_H
+#define _LIBCPP___ALGORITHM_FIND_END_OF_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1 __find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                                                           _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+                                                           _BinaryPredicate __pred, forward_iterator_tag,
+                                                           forward_iterator_tag) {
+  // modeled after search algorithm
+  _ForwardIterator1 __r = __last1; // __last1 is the "default" answer
+  if (__first2 == __last2)
+    return __r;
+  while (true) {
+    while (true) {
+      if (__first1 == __last1) // if source exhausted return last correct answer
+        return __r;            //    (or __last1 if never found)
+      if (__pred(*__first1, *__first2))
+        break;
+      ++__first1;
+    }
+    // *__first1 matches *__first2, now match elements after here
+    _ForwardIterator1 __m1 = __first1;
+    _ForwardIterator2 __m2 = __first2;
+    while (true) {
+      if (++__m2 == __last2) { // Pattern exhaused, record answer and search for another one
+        __r = __first1;
+        ++__first1;
+        break;
+      }
+      if (++__m1 == __last1) // Source exhausted, return last answer
+        return __r;
+      if (!__pred(*__m1, *__m2)) // mismatch, restart with a new __first
+      {
+        ++__first1;
+        break;
+      } // else there is a match, check next elements
+    }
+  }
+}
+
+template <class _BinaryPredicate, class _BidirectionalIterator1, class _BidirectionalIterator2>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _BidirectionalIterator1 __find_end(
+    _BidirectionalIterator1 __first1, _BidirectionalIterator1 __last1, _BidirectionalIterator2 __first2,
+    _BidirectionalIterator2 __last2, _BinaryPredicate __pred, bidirectional_iterator_tag, bidirectional_iterator_tag) {
+  // modeled after search algorithm (in reverse)
+  if (__first2 == __last2)
+    return __last1; // Everything matches an empty sequence
+  _BidirectionalIterator1 __l1 = __last1;
+  _BidirectionalIterator2 __l2 = __last2;
+  --__l2;
+  while (true) {
+    // Find last element in sequence 1 that matchs *(__last2-1), with a mininum of loop checks
+    while (true) {
+      if (__first1 == __l1) // return __last1 if no element matches *__first2
+        return __last1;
+      if (__pred(*--__l1, *__l2))
+        break;
+    }
+    // *__l1 matches *__l2, now match elements before here
+    _BidirectionalIterator1 __m1 = __l1;
+    _BidirectionalIterator2 __m2 = __l2;
+    while (true) {
+      if (__m2 == __first2) // If pattern exhausted, __m1 is the answer (works for 1 element pattern)
+        return __m1;
+      if (__m1 == __first1) // Otherwise if source exhaused, pattern not found
+        return __last1;
+      if (!__pred(*--__m1, *--__m2)) // if there is a mismatch, restart with a new __l1
+      {
+        break;
+      } // else there is a match, check next elements
+    }
+  }
+}
+
+template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _RandomAccessIterator1 __find_end(
+    _RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+    _RandomAccessIterator2 __last2, _BinaryPredicate __pred, random_access_iterator_tag, random_access_iterator_tag) {
+  // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
+  typename iterator_traits<_RandomAccessIterator2>::difference_type __len2 = __last2 - __first2;
+  if (__len2 == 0)
+    return __last1;
+  typename iterator_traits<_RandomAccessIterator1>::difference_type __len1 = __last1 - __first1;
+  if (__len1 < __len2)
+    return __last1;
+  const _RandomAccessIterator1 __s = __first1 + (__len2 - 1); // End of pattern match can't go before here
+  _RandomAccessIterator1 __l1 = __last1;
+  _RandomAccessIterator2 __l2 = __last2;
+  --__l2;
+  while (true) {
+    while (true) {
+      if (__s == __l1)
+        return __last1;
+      if (__pred(*--__l1, *__l2))
+        break;
+    }
+    _RandomAccessIterator1 __m1 = __l1;
+    _RandomAccessIterator2 __m2 = __l2;
+    while (true) {
+      if (__m2 == __first2)
+        return __m1;
+      // no need to check range on __m1 because __s guarantees we have enough source
+      if (!__pred(*--__m1, *--__m2)) {
+        break;
+      }
+    }
+  }
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1
+find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+         _BinaryPredicate __pred) {
+  return _VSTD::__find_end<_BinaryPredicate&>(
+      __first1, __last1, __first2, __last2, __pred, typename iterator_traits<_ForwardIterator1>::iterator_category(),
+      typename iterator_traits<_ForwardIterator2>::iterator_category());
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1
+find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
+  typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
+  typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
+  return _VSTD::find_end(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FIND_END_OF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/find_first_of.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/find_first_of.h
new file mode 100644
index 00000000000..79a00acb9ee
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/find_first_of.h
@@ -0,0 +1,52 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FIND_FIRST_OF_H
+#define _LIBCPP___ALGORITHM_FIND_FIRST_OF_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _ForwardIterator1 __find_first_of_ce(_ForwardIterator1 __first1,
+                                                                   _ForwardIterator1 __last1,
+                                                                   _ForwardIterator2 __first2,
+                                                                   _ForwardIterator2 __last2, _BinaryPredicate __pred) {
+  for (; __first1 != __last1; ++__first1)
+    for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
+      if (__pred(*__first1, *__j))
+        return __first1;
+  return __last1;
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1
+find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+              _ForwardIterator2 __last2, _BinaryPredicate __pred) {
+  return _VSTD::__find_first_of_ce(__first1, __last1, __first2, __last2, __pred);
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1 find_first_of(
+    _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
+  typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
+  typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
+  return _VSTD::__find_first_of_ce(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FIND_FIRST_OF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/find_if.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/find_if.h
new file mode 100644
index 00000000000..a94196a16ac
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/find_if.h
@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FIND_IF_H
+#define _LIBCPP___ALGORITHM_FIND_IF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _InputIterator
+find_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
+  for (; __first != __last; ++__first)
+    if (__pred(*__first))
+      break;
+  return __first;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FIND_IF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/find_if_not.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/find_if_not.h
new file mode 100644
index 00000000000..e057db5efa4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/find_if_not.h
@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FIND_IF_NOT_H
+#define _LIBCPP___ALGORITHM_FIND_IF_NOT_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _InputIterator
+find_if_not(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
+  for (; __first != __last; ++__first)
+    if (!__pred(*__first))
+      break;
+  return __first;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FIND_IF_NOT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/for_each.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/for_each.h
new file mode 100644
index 00000000000..1612ffa5c00
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/for_each.h
@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FOR_EACH_H
+#define _LIBCPP___ALGORITHM_FOR_EACH_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Function>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _Function for_each(_InputIterator __first,
+                                                                                  _InputIterator __last,
+                                                                                  _Function __f) {
+  for (; __first != __last; ++__first)
+    __f(*__first);
+  return __f;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FOR_EACH_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/for_each_n.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/for_each_n.h
new file mode 100644
index 00000000000..00e3fb9c1db
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/for_each_n.h
@@ -0,0 +1,42 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FOR_EACH_N_H
+#define _LIBCPP___ALGORITHM_FOR_EACH_N_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+template <class _InputIterator, class _Size, class _Function>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _InputIterator for_each_n(_InputIterator __first,
+                                                                                         _Size __orig_n,
+                                                                                         _Function __f) {
+  typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize;
+  _IntegralSize __n = __orig_n;
+  while (__n > 0) {
+    __f(*__first);
+    ++__first;
+    --__n;
+  }
+  return __first;
+}
+
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FOR_EACH_N_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/generate.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/generate.h
new file mode 100644
index 00000000000..10834cdb743
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/generate.h
@@ -0,0 +1,31 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_GENERATE_H
+#define _LIBCPP___ALGORITHM_GENERATE_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Generator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+generate(_ForwardIterator __first, _ForwardIterator __last, _Generator __gen)
+{
+    for (; __first != __last; ++__first)
+        *__first = __gen();
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_GENERATE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/generate_n.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/generate_n.h
new file mode 100644
index 00000000000..595007cdd34
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/generate_n.h
@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_GENERATE_N_H
+#define _LIBCPP___ALGORITHM_GENERATE_N_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _OutputIterator, class _Size, class _Generator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+generate_n(_OutputIterator __first, _Size __orig_n, _Generator __gen)
+{
+    typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize;
+    _IntegralSize __n = __orig_n;
+    for (; __n > 0; ++__first, (void) --__n)
+        *__first = __gen();
+    return __first;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_GENERATE_N_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/half_positive.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/half_positive.h
new file mode 100644
index 00000000000..5d36ff5da98
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/half_positive.h
@@ -0,0 +1,49 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_HALF_POSITIVE_H
+#define _LIBCPP___ALGORITHM_HALF_POSITIVE_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Perform division by two quickly for positive integers (llvm.org/PR39129)
+
+template <typename _Integral>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename enable_if
+<
+    is_integral<_Integral>::value,
+    _Integral
+>::type
+__half_positive(_Integral __value)
+{
+    return static_cast<_Integral>(static_cast<typename make_unsigned<_Integral>::type>(__value) / 2);
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename enable_if
+<
+    !is_integral<_Tp>::value,
+    _Tp
+>::type
+__half_positive(_Tp __value)
+{
+    return __value / 2;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_HALF_POSITIVE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/includes.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/includes.h
new file mode 100644
index 00000000000..9cc54d938dc
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/includes.h
@@ -0,0 +1,62 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_INCLUDES_H
+#define _LIBCPP___ALGORITHM_INCLUDES_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _InputIterator1, class _InputIterator2>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+__includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
+           _Compare __comp)
+{
+    for (; __first2 != __last2; ++__first1)
+    {
+        if (__first1 == __last1 || __comp(*__first2, *__first1))
+            return false;
+        if (!__comp(*__first1, *__first2))
+            ++__first2;
+    }
+    return true;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
+         _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    return _VSTD::__includes<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
+}
+
+template <class _InputIterator1, class _InputIterator2>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2)
+{
+    return _VSTD::includes(__first1, __last1, __first2, __last2,
+                          __less<typename iterator_traits<_InputIterator1>::value_type,
+                                 typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_INCLUDES_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/inplace_merge.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/inplace_merge.h
new file mode 100644
index 00000000000..c74633a74cf
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/inplace_merge.h
@@ -0,0 +1,231 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_INPLACE_MERGE_H
+#define _LIBCPP___ALGORITHM_INPLACE_MERGE_H
+
+#include <__config>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/comp.h>
+#include <__algorithm/lower_bound.h>
+#include <__algorithm/min.h>
+#include <__algorithm/move.h>
+#include <__algorithm/rotate.h>
+#include <__algorithm/upper_bound.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/swap.h>
+#include <memory>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Predicate>
+class __invert // invert the sense of a comparison
+{
+private:
+    _Predicate __p_;
+public:
+    _LIBCPP_INLINE_VISIBILITY __invert() {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __invert(_Predicate __p) : __p_(__p) {}
+
+    template <class _T1>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _T1& __x) {return !__p_(__x);}
+
+    template <class _T1, class _T2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _T1& __x, const _T2& __y) {return __p_(__y, __x);}
+};
+
+template <class _Compare, class _InputIterator1, class _InputIterator2,
+          class _OutputIterator>
+void __half_inplace_merge(_InputIterator1 __first1, _InputIterator1 __last1,
+                          _InputIterator2 __first2, _InputIterator2 __last2,
+                          _OutputIterator __result, _Compare __comp)
+{
+    for (; __first1 != __last1; ++__result)
+    {
+        if (__first2 == __last2)
+        {
+            _VSTD::move(__first1, __last1, __result);
+            return;
+        }
+
+        if (__comp(*__first2, *__first1))
+        {
+            *__result = _VSTD::move(*__first2);
+            ++__first2;
+        }
+        else
+        {
+            *__result = _VSTD::move(*__first1);
+            ++__first1;
+        }
+    }
+    // __first2 through __last2 are already in the right spot.
+}
+
+template <class _Compare, class _BidirectionalIterator>
+void
+__buffered_inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
+                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
+                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
+                typename iterator_traits<_BidirectionalIterator>::value_type* __buff)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    __destruct_n __d(0);
+    unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
+    if (__len1 <= __len2)
+    {
+        value_type* __p = __buff;
+        for (_BidirectionalIterator __i = __first; __i != __middle; __d.template __incr<value_type>(), (void) ++__i, (void) ++__p)
+            ::new ((void*)__p) value_type(_VSTD::move(*__i));
+        _VSTD::__half_inplace_merge<_Compare>(__buff, __p, __middle, __last, __first, __comp);
+    }
+    else
+    {
+        value_type* __p = __buff;
+        for (_BidirectionalIterator __i = __middle; __i != __last; __d.template __incr<value_type>(), (void) ++__i, (void) ++__p)
+            ::new ((void*)__p) value_type(_VSTD::move(*__i));
+        typedef reverse_iterator<_BidirectionalIterator> _RBi;
+        typedef reverse_iterator<value_type*> _Rv;
+        typedef __invert<_Compare> _Inverted;
+        _VSTD::__half_inplace_merge<_Inverted>(_Rv(__p), _Rv(__buff),
+                                    _RBi(__middle), _RBi(__first),
+                                    _RBi(__last), _Inverted(__comp));
+    }
+}
+
+template <class _Compare, class _BidirectionalIterator>
+void
+__inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
+                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
+                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
+                typename iterator_traits<_BidirectionalIterator>::value_type* __buff, ptrdiff_t __buff_size)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
+    while (true)
+    {
+        // if __middle == __last, we're done
+        if (__len2 == 0)
+            return;
+        if (__len1 <= __buff_size || __len2 <= __buff_size)
+            return _VSTD::__buffered_inplace_merge<_Compare>
+                   (__first, __middle, __last, __comp, __len1, __len2, __buff);
+        // shrink [__first, __middle) as much as possible (with no moves), returning if it shrinks to 0
+        for (; true; ++__first, (void) --__len1)
+        {
+            if (__len1 == 0)
+                return;
+            if (__comp(*__middle, *__first))
+                break;
+        }
+        // __first < __middle < __last
+        // *__first > *__middle
+        // partition [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last) such that
+        //     all elements in:
+        //         [__first, __m1)  <= [__middle, __m2)
+        //         [__middle, __m2) <  [__m1, __middle)
+        //         [__m1, __middle) <= [__m2, __last)
+        //     and __m1 or __m2 is in the middle of its range
+        _BidirectionalIterator __m1;  // "median" of [__first, __middle)
+        _BidirectionalIterator __m2;  // "median" of [__middle, __last)
+        difference_type __len11;      // distance(__first, __m1)
+        difference_type __len21;      // distance(__middle, __m2)
+        // binary search smaller range
+        if (__len1 < __len2)
+        {   // __len >= 1, __len2 >= 2
+            __len21 = __len2 / 2;
+            __m2 = __middle;
+            _VSTD::advance(__m2, __len21);
+            __m1 = _VSTD::__upper_bound<_Compare>(__first, __middle, *__m2, __comp);
+            __len11 = _VSTD::distance(__first, __m1);
+        }
+        else
+        {
+            if (__len1 == 1)
+            {   // __len1 >= __len2 && __len2 > 0, therefore __len2 == 1
+                // It is known *__first > *__middle
+                swap(*__first, *__middle);
+                return;
+            }
+            // __len1 >= 2, __len2 >= 1
+            __len11 = __len1 / 2;
+            __m1 = __first;
+            _VSTD::advance(__m1, __len11);
+            __m2 = _VSTD::__lower_bound<_Compare>(__middle, __last, *__m1, __comp);
+            __len21 = _VSTD::distance(__middle, __m2);
+        }
+        difference_type __len12 = __len1 - __len11;  // distance(__m1, __middle)
+        difference_type __len22 = __len2 - __len21;  // distance(__m2, __last)
+        // [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last)
+        // swap middle two partitions
+        __middle = _VSTD::rotate(__m1, __middle, __m2);
+        // __len12 and __len21 now have swapped meanings
+        // merge smaller range with recursive call and larger with tail recursion elimination
+        if (__len11 + __len21 < __len12 + __len22)
+        {
+            _VSTD::__inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
+//          _VSTD::__inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
+            __first = __middle;
+            __middle = __m2;
+            __len1 = __len12;
+            __len2 = __len22;
+        }
+        else
+        {
+            _VSTD::__inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
+//          _VSTD::__inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
+            __last = __middle;
+            __middle = __m1;
+            __len1 = __len11;
+            __len2 = __len21;
+        }
+    }
+}
+
+template <class _BidirectionalIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
+              _Compare __comp)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
+    difference_type __len1 = _VSTD::distance(__first, __middle);
+    difference_type __len2 = _VSTD::distance(__middle, __last);
+    difference_type __buf_size = _VSTD::min(__len1, __len2);
+    pair<value_type*, ptrdiff_t> __buf = _VSTD::get_temporary_buffer<value_type>(__buf_size);
+    unique_ptr<value_type, __return_temporary_buffer> __h(__buf.first);
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __comp, __len1, __len2,
+                                            __buf.first, __buf.second);
+}
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last)
+{
+    _VSTD::inplace_merge(__first, __middle, __last,
+                        __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_INPLACE_MERGE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_heap.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_heap.h
new file mode 100644
index 00000000000..7fd5d6ff9a0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_heap.h
@@ -0,0 +1,43 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IS_HEAP_H
+#define _LIBCPP___ALGORITHM_IS_HEAP_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/is_heap_until.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _RandomAccessIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    return _VSTD::is_heap_until(__first, __last, __comp) == __last;
+}
+
+template<class _RandomAccessIterator>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    return _VSTD::is_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IS_HEAP_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_heap_until.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_heap_until.h
new file mode 100644
index 00000000000..99291c102bf
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_heap_until.h
@@ -0,0 +1,60 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IS_HEAP_UNTIL_H
+#define _LIBCPP___ALGORITHM_IS_HEAP_UNTIL_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _RandomAccessIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX17 _RandomAccessIterator
+is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    difference_type __len = __last - __first;
+    difference_type __p = 0;
+    difference_type __c = 1;
+    _RandomAccessIterator __pp = __first;
+    while (__c < __len)
+    {
+        _RandomAccessIterator __cp = __first + __c;
+        if (__comp(*__pp, *__cp))
+            return __cp;
+        ++__c;
+        ++__cp;
+        if (__c == __len)
+            return __last;
+        if (__comp(*__pp, *__cp))
+            return __cp;
+        ++__p;
+        ++__pp;
+        __c = 2 * __p + 1;
+    }
+    return __last;
+}
+
+template<class _RandomAccessIterator>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_RandomAccessIterator
+is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    return _VSTD::is_heap_until(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IS_HEAP_UNTIL_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_partitioned.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_partitioned.h
new file mode 100644
index 00000000000..e5b2214aa06
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_partitioned.h
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IS_PARTITIONED_H
+#define _LIBCPP___ALGORITHM_IS_PARTITIONED_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+is_partitioned(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+        if (!__pred(*__first))
+            break;
+    if ( __first == __last )
+        return true;
+    ++__first;
+    for (; __first != __last; ++__first)
+        if (__pred(*__first))
+            return false;
+    return true;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IS_PARTITIONED_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_permutation.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_permutation.h
new file mode 100644
index 00000000000..344aa763ad0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_permutation.h
@@ -0,0 +1,162 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IS_PERMUTATION_H
+#define _LIBCPP___ALGORITHM_IS_PERMUTATION_H
+
+#include <__algorithm/comp.h>
+#include <__config>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+               _BinaryPredicate __pred) {
+  //  shorten sequences as much as possible by lopping of any equal prefix
+  for (; __first1 != __last1; ++__first1, (void)++__first2)
+    if (!__pred(*__first1, *__first2))
+      break;
+  if (__first1 == __last1)
+    return true;
+
+  //  __first1 != __last1 && *__first1 != *__first2
+  typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
+  _D1 __l1 = _VSTD::distance(__first1, __last1);
+  if (__l1 == _D1(1))
+    return false;
+  _ForwardIterator2 __last2 = _VSTD::next(__first2, __l1);
+  // For each element in [f1, l1) see if there are the same number of
+  //    equal elements in [f2, l2)
+  for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i) {
+    //  Have we already counted the number of *__i in [f1, l1)?
+    _ForwardIterator1 __match = __first1;
+    for (; __match != __i; ++__match)
+      if (__pred(*__match, *__i))
+        break;
+    if (__match == __i) {
+      // Count number of *__i in [f2, l2)
+      _D1 __c2 = 0;
+      for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
+        if (__pred(*__i, *__j))
+          ++__c2;
+      if (__c2 == 0)
+        return false;
+      // Count number of *__i in [__i, l1) (we can start with 1)
+      _D1 __c1 = 1;
+      for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
+        if (__pred(*__i, *__j))
+          ++__c1;
+      if (__c1 != __c2)
+        return false;
+    }
+  }
+  return true;
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2) {
+  typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
+  typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
+  return _VSTD::is_permutation(__first1, __last1, __first2, __equal_to<__v1, __v2>());
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+__is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+                 _ForwardIterator2 __last2, _BinaryPredicate __pred, forward_iterator_tag, forward_iterator_tag) {
+  //  shorten sequences as much as possible by lopping of any equal prefix
+  for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void)++__first2)
+    if (!__pred(*__first1, *__first2))
+      break;
+  if (__first1 == __last1)
+    return __first2 == __last2;
+  else if (__first2 == __last2)
+    return false;
+
+  typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
+  _D1 __l1 = _VSTD::distance(__first1, __last1);
+
+  typedef typename iterator_traits<_ForwardIterator2>::difference_type _D2;
+  _D2 __l2 = _VSTD::distance(__first2, __last2);
+  if (__l1 != __l2)
+    return false;
+
+  // For each element in [f1, l1) see if there are the same number of
+  //    equal elements in [f2, l2)
+  for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i) {
+    //  Have we already counted the number of *__i in [f1, l1)?
+    _ForwardIterator1 __match = __first1;
+    for (; __match != __i; ++__match)
+      if (__pred(*__match, *__i))
+        break;
+    if (__match == __i) {
+      // Count number of *__i in [f2, l2)
+      _D1 __c2 = 0;
+      for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
+        if (__pred(*__i, *__j))
+          ++__c2;
+      if (__c2 == 0)
+        return false;
+      // Count number of *__i in [__i, l1) (we can start with 1)
+      _D1 __c1 = 1;
+      for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
+        if (__pred(*__i, *__j))
+          ++__c1;
+      if (__c1 != __c2)
+        return false;
+    }
+  }
+  return true;
+}
+
+template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool __is_permutation(_RandomAccessIterator1 __first1, _RandomAccessIterator2 __last1,
+                                                    _RandomAccessIterator1 __first2, _RandomAccessIterator2 __last2,
+                                                    _BinaryPredicate __pred, random_access_iterator_tag,
+                                                    random_access_iterator_tag) {
+  if (_VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
+    return false;
+  return _VSTD::is_permutation<_RandomAccessIterator1, _RandomAccessIterator2,
+                               _BinaryPredicate&>(__first1, __last1, __first2, __pred);
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+               _ForwardIterator2 __last2, _BinaryPredicate __pred) {
+  return _VSTD::__is_permutation<_BinaryPredicate&>(
+      __first1, __last1, __first2, __last2, __pred, typename iterator_traits<_ForwardIterator1>::iterator_category(),
+      typename iterator_traits<_ForwardIterator2>::iterator_category());
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+               _ForwardIterator2 __last2) {
+  typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
+  typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
+  return _VSTD::__is_permutation(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>(),
+                                 typename iterator_traits<_ForwardIterator1>::iterator_category(),
+                                 typename iterator_traits<_ForwardIterator2>::iterator_category());
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IS_PERMUTATION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_sorted.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_sorted.h
new file mode 100644
index 00000000000..c6954934e8c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_sorted.h
@@ -0,0 +1,43 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IS_SORTED_H
+#define _LIBCPP___ALGORITHM_IS_SORTED_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/is_sorted_until.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+is_sorted(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    return _VSTD::is_sorted_until(__first, __last, __comp) == __last;
+}
+
+template<class _ForwardIterator>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+is_sorted(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::is_sorted(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IS_SORTED_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_sorted_until.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_sorted_until.h
new file mode 100644
index 00000000000..5b6385991a7
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/is_sorted_until.h
@@ -0,0 +1,50 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IS_SORTED_UNTIL_H
+#define _LIBCPP___ALGORITHM_IS_SORTED_UNTIL_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+is_sorted_until(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+        {
+            if (__comp(*__i, *__first))
+                return __i;
+            __first = __i;
+        }
+    }
+    return __last;
+}
+
+template<class _ForwardIterator>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator
+is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::is_sorted_until(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IS_SORTED_UNTIL_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/iter_swap.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/iter_swap.h
new file mode 100644
index 00000000000..9f7d0d77630
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/iter_swap.h
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_ITER_SWAP_H
+#define _LIBCPP___ALGORITHM_ITER_SWAP_H
+
+#include <__config>
+#include <__utility/declval.h>
+#include <__utility/swap.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 void iter_swap(_ForwardIterator1 __a,
+                                                                              _ForwardIterator2 __b)
+    //                                  _NOEXCEPT_(_NOEXCEPT_(swap(*__a, *__b)))
+    _NOEXCEPT_(_NOEXCEPT_(swap(*declval<_ForwardIterator1>(), *declval<_ForwardIterator2>()))) {
+  swap(*__a, *__b);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_ITER_SWAP_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/lexicographical_compare.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/lexicographical_compare.h
new file mode 100644
index 00000000000..a110a58c01c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/lexicographical_compare.h
@@ -0,0 +1,63 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_LEXICOGRAPHICAL_COMPARE_H
+#define _LIBCPP___ALGORITHM_LEXICOGRAPHICAL_COMPARE_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _InputIterator1, class _InputIterator2>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+__lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
+                          _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
+{
+    for (; __first2 != __last2; ++__first1, (void) ++__first2)
+    {
+        if (__first1 == __last1 || __comp(*__first1, *__first2))
+            return true;
+        if (__comp(*__first2, *__first1))
+            return false;
+    }
+    return false;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
+                        _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    return _VSTD::__lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
+}
+
+template <class _InputIterator1, class _InputIterator2>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
+                        _InputIterator2 __first2, _InputIterator2 __last2)
+{
+    return _VSTD::lexicographical_compare(__first1, __last1, __first2, __last2,
+                                         __less<typename iterator_traits<_InputIterator1>::value_type,
+                                                typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_LEXICOGRAPHICAL_COMPARE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/lower_bound.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/lower_bound.h
new file mode 100644
index 00000000000..ddaecb045b3
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/lower_bound.h
@@ -0,0 +1,66 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_LOWER_BOUND_H
+#define _LIBCPP___ALGORITHM_LOWER_BOUND_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/half_positive.h>
+#include <iterator>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _ForwardIterator, class _Tp>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+__lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
+    difference_type __len = _VSTD::distance(__first, __last);
+    while (__len != 0)
+    {
+        difference_type __l2 = _VSTD::__half_positive(__len);
+        _ForwardIterator __m = __first;
+        _VSTD::advance(__m, __l2);
+        if (__comp(*__m, __value_))
+        {
+            __first = ++__m;
+            __len -= __l2 + 1;
+        }
+        else
+            __len = __l2;
+    }
+    return __first;
+}
+
+template <class _ForwardIterator, class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator
+lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+    return _VSTD::__lower_bound<_Compare&>(__first, __last, __value_, __comp);
+}
+
+template <class _ForwardIterator, class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator
+lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
+{
+    return _VSTD::lower_bound(__first, __last, __value_,
+                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_LOWER_BOUND_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/make_heap.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/make_heap.h
new file mode 100644
index 00000000000..b3defd4de07
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/make_heap.h
@@ -0,0 +1,59 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MAKE_HEAP_H
+#define _LIBCPP___ALGORITHM_MAKE_HEAP_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/sift_down.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _RandomAccessIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 void
+__make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    difference_type __n = __last - __first;
+    if (__n > 1)
+    {
+        // start from the first parent, there is no need to consider children
+        for (difference_type __start = (__n - 2) / 2; __start >= 0; --__start)
+        {
+            _VSTD::__sift_down<_Compare>(__first, __last, __comp, __n, __first + __start);
+        }
+    }
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    _VSTD::__make_heap<_Comp_ref>(__first, __last, __comp);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    _VSTD::make_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MAKE_HEAP_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/max.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/max.h
new file mode 100644
index 00000000000..2fa97cad87f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/max.h
@@ -0,0 +1,70 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MAX_H
+#define _LIBCPP___ALGORITHM_MAX_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/max_element.h>
+#include <initializer_list>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const _Tp&
+max(const _Tp& __a, const _Tp& __b, _Compare __comp)
+{
+    return __comp(__a, __b) ? __b : __a;
+}
+
+template <class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const _Tp&
+max(const _Tp& __a, const _Tp& __b)
+{
+    return _VSTD::max(__a, __b, __less<_Tp>());
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp
+max(initializer_list<_Tp> __t, _Compare __comp)
+{
+    return *_VSTD::max_element(__t.begin(), __t.end(), __comp);
+}
+
+template<class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp
+max(initializer_list<_Tp> __t)
+{
+    return *_VSTD::max_element(__t.begin(), __t.end(), __less<_Tp>());
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_MAX_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/max_element.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/max_element.h
new file mode 100644
index 00000000000..c51519605af
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/max_element.h
@@ -0,0 +1,53 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MAX_ELEMENT_H
+#define _LIBCPP___ALGORITHM_MAX_ELEMENT_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_ForwardIterator
+max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    static_assert(__is_cpp17_forward_iterator<_ForwardIterator>::value,
+        "std::max_element requires a ForwardIterator");
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+            if (__comp(*__first, *__i))
+                __first = __i;
+    }
+    return __first;
+}
+
+
+template <class _ForwardIterator>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_ForwardIterator
+max_element(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::max_element(__first, __last,
+              __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MAX_ELEMENT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/merge.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/merge.h
new file mode 100644
index 00000000000..480380db6ca
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/merge.h
@@ -0,0 +1,71 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MERGE_H
+#define _LIBCPP___ALGORITHM_MERGE_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/copy.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+__merge(_InputIterator1 __first1, _InputIterator1 __last1,
+        _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    for (; __first1 != __last1; ++__result)
+    {
+        if (__first2 == __last2)
+            return _VSTD::copy(__first1, __last1, __result);
+        if (__comp(*__first2, *__first1))
+        {
+            *__result = *__first2;
+            ++__first2;
+        }
+        else
+        {
+            *__result = *__first1;
+            ++__first1;
+        }
+    }
+    return _VSTD::copy(__first2, __last2, __result);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+merge(_InputIterator1 __first1, _InputIterator1 __last1,
+      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+merge(_InputIterator1 __first1, _InputIterator1 __last1,
+      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
+{
+    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
+    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
+    return _VSTD::merge(__first1, __last1, __first2, __last2, __result, __less<__v1, __v2>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MERGE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/min.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/min.h
new file mode 100644
index 00000000000..9fea7f70a2b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/min.h
@@ -0,0 +1,70 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MIN_H
+#define _LIBCPP___ALGORITHM_MIN_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/min_element.h>
+#include <initializer_list>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const _Tp&
+min(const _Tp& __a, const _Tp& __b, _Compare __comp)
+{
+    return __comp(__b, __a) ? __b : __a;
+}
+
+template <class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const _Tp&
+min(const _Tp& __a, const _Tp& __b)
+{
+    return _VSTD::min(__a, __b, __less<_Tp>());
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp
+min(initializer_list<_Tp> __t, _Compare __comp)
+{
+    return *_VSTD::min_element(__t.begin(), __t.end(), __comp);
+}
+
+template<class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp
+min(initializer_list<_Tp> __t)
+{
+    return *_VSTD::min_element(__t.begin(), __t.end(), __less<_Tp>());
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_MIN_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/min_element.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/min_element.h
new file mode 100644
index 00000000000..9bfd0793c69
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/min_element.h
@@ -0,0 +1,52 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MIN_ELEMENT_H
+#define _LIBCPP___ALGORITHM_MIN_ELEMENT_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_ForwardIterator
+min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    static_assert(__is_cpp17_forward_iterator<_ForwardIterator>::value,
+        "std::min_element requires a ForwardIterator");
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+            if (__comp(*__i, *__first))
+                __first = __i;
+    }
+    return __first;
+}
+
+template <class _ForwardIterator>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_ForwardIterator
+min_element(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::min_element(__first, __last,
+              __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MIN_ELEMENT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/minmax.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/minmax.h
new file mode 100644
index 00000000000..a96a5b252c0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/minmax.h
@@ -0,0 +1,96 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MINMAX_H
+#define _LIBCPP___ALGORITHM_MINMAX_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <initializer_list>
+#include <utility>
+
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<const _Tp&, const _Tp&>
+minmax(const _Tp& __a, const _Tp& __b, _Compare __comp)
+{
+    return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a) :
+                              pair<const _Tp&, const _Tp&>(__a, __b);
+}
+
+template<class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<const _Tp&, const _Tp&>
+minmax(const _Tp& __a, const _Tp& __b)
+{
+    return _VSTD::minmax(__a, __b, __less<_Tp>());
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<_Tp, _Tp>
+minmax(initializer_list<_Tp> __t, _Compare __comp)
+{
+    typedef typename initializer_list<_Tp>::const_iterator _Iter;
+    _Iter __first = __t.begin();
+    _Iter __last  = __t.end();
+    pair<_Tp, _Tp> __result(*__first, *__first);
+
+    ++__first;
+    if (__t.size() % 2 == 0)
+    {
+        if (__comp(*__first,  __result.first))
+            __result.first  = *__first;
+        else
+            __result.second = *__first;
+        ++__first;
+    }
+
+    while (__first != __last)
+    {
+        _Tp __prev = *__first++;
+        if (__comp(*__first, __prev)) {
+            if ( __comp(*__first, __result.first)) __result.first  = *__first;
+            if (!__comp(__prev, __result.second))  __result.second = __prev;
+            }
+        else {
+            if ( __comp(__prev, __result.first))    __result.first  = __prev;
+            if (!__comp(*__first, __result.second)) __result.second = *__first;
+            }
+
+        __first++;
+    }
+    return __result;
+}
+
+template<class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<_Tp, _Tp>
+minmax(initializer_list<_Tp> __t)
+{
+    return _VSTD::minmax(__t, __less<_Tp>());
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MINMAX_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/minmax_element.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/minmax_element.h
new file mode 100644
index 00000000000..d21ff6f8dc5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/minmax_element.h
@@ -0,0 +1,85 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H
+#define _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__iterator/iterator_traits.h>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<_ForwardIterator, _ForwardIterator>
+minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+  static_assert(__is_cpp17_forward_iterator<_ForwardIterator>::value,
+        "std::minmax_element requires a ForwardIterator");
+  pair<_ForwardIterator, _ForwardIterator> __result(__first, __first);
+  if (__first != __last)
+  {
+      if (++__first != __last)
+      {
+          if (__comp(*__first, *__result.first))
+              __result.first = __first;
+          else
+              __result.second = __first;
+          while (++__first != __last)
+          {
+              _ForwardIterator __i = __first;
+              if (++__first == __last)
+              {
+                  if (__comp(*__i, *__result.first))
+                      __result.first = __i;
+                  else if (!__comp(*__i, *__result.second))
+                      __result.second = __i;
+                  break;
+              }
+              else
+              {
+                  if (__comp(*__first, *__i))
+                  {
+                      if (__comp(*__first, *__result.first))
+                          __result.first = __first;
+                      if (!__comp(*__i, *__result.second))
+                          __result.second = __i;
+                  }
+                  else
+                  {
+                      if (__comp(*__i, *__result.first))
+                          __result.first = __i;
+                      if (!__comp(*__first, *__result.second))
+                          __result.second = __first;
+                  }
+              }
+          }
+      }
+  }
+  return __result;
+}
+
+template <class _ForwardIterator>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<_ForwardIterator, _ForwardIterator>
+minmax_element(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::minmax_element(__first, __last,
+              __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/mismatch.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/mismatch.h
new file mode 100644
index 00000000000..7a01a985934
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/mismatch.h
@@ -0,0 +1,67 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MISMATCH_H
+#define _LIBCPP___ALGORITHM_MISMATCH_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__iterator/iterator_traits.h>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 pair<_InputIterator1, _InputIterator2>
+    mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred) {
+  for (; __first1 != __last1; ++__first1, (void)++__first2)
+    if (!__pred(*__first1, *__first2))
+      break;
+  return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
+}
+
+template <class _InputIterator1, class _InputIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 pair<_InputIterator1, _InputIterator2>
+    mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2) {
+  typedef typename iterator_traits<_InputIterator1>::value_type __v1;
+  typedef typename iterator_traits<_InputIterator2>::value_type __v2;
+  return _VSTD::mismatch(__first1, __last1, __first2, __equal_to<__v1, __v2>());
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 pair<_InputIterator1, _InputIterator2>
+    mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
+             _BinaryPredicate __pred) {
+  for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void)++__first2)
+    if (!__pred(*__first1, *__first2))
+      break;
+  return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
+}
+
+template <class _InputIterator1, class _InputIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 pair<_InputIterator1, _InputIterator2>
+    mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) {
+  typedef typename iterator_traits<_InputIterator1>::value_type __v1;
+  typedef typename iterator_traits<_InputIterator2>::value_type __v2;
+  return _VSTD::mismatch(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MISMATCH_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/move.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/move.h
new file mode 100644
index 00000000000..7430bf08743
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/move.h
@@ -0,0 +1,78 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MOVE_H
+#define _LIBCPP___ALGORITHM_MOVE_H
+
+#include <__config>
+#include <__algorithm/unwrap_iter.h>
+#include <__utility/move.h>
+#include <cstring>
+#include <utility>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// move
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+_OutputIterator
+__move_constexpr(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    for (; __first != __last; ++__first, (void) ++__result)
+        *__result = _VSTD::move(*__first);
+    return __result;
+}
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+_OutputIterator
+__move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    return _VSTD::__move_constexpr(__first, __last, __result);
+}
+
+template <class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+typename enable_if
+<
+    is_same<typename remove_const<_Tp>::type, _Up>::value &&
+    is_trivially_move_assignable<_Up>::value,
+    _Up*
+>::type
+__move(_Tp* __first, _Tp* __last, _Up* __result)
+{
+    const size_t __n = static_cast<size_t>(__last - __first);
+    if (__n > 0)
+        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
+    return __result + __n;
+}
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    if (__libcpp_is_constant_evaluated()) {
+        return _VSTD::__move_constexpr(__first, __last, __result);
+    } else {
+        return _VSTD::__rewrap_iter(__result,
+            _VSTD::__move(_VSTD::__unwrap_iter(__first),
+                          _VSTD::__unwrap_iter(__last),
+                          _VSTD::__unwrap_iter(__result)));
+    }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MOVE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/move_backward.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/move_backward.h
new file mode 100644
index 00000000000..ee72d39764c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/move_backward.h
@@ -0,0 +1,79 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MOVE_BACKWARD_H
+#define _LIBCPP___ALGORITHM_MOVE_BACKWARD_H
+
+#include <__config>
+#include <__algorithm/unwrap_iter.h>
+#include <cstring>
+#include <utility>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+_OutputIterator
+__move_backward_constexpr(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    while (__first != __last)
+        *--__result = _VSTD::move(*--__last);
+    return __result;
+}
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+_OutputIterator
+__move_backward(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    return _VSTD::__move_backward_constexpr(__first, __last, __result);
+}
+
+template <class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+typename enable_if
+<
+    is_same<typename remove_const<_Tp>::type, _Up>::value &&
+    is_trivially_move_assignable<_Up>::value,
+    _Up*
+>::type
+__move_backward(_Tp* __first, _Tp* __last, _Up* __result)
+{
+    const size_t __n = static_cast<size_t>(__last - __first);
+    if (__n > 0)
+    {
+        __result -= __n;
+        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
+    }
+    return __result;
+}
+
+template <class _BidirectionalIterator1, class _BidirectionalIterator2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_BidirectionalIterator2
+move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
+              _BidirectionalIterator2 __result)
+{
+    if (__libcpp_is_constant_evaluated()) {
+        return _VSTD::__move_backward_constexpr(__first, __last, __result);
+    } else {
+        return _VSTD::__rewrap_iter(__result,
+            _VSTD::__move_backward(_VSTD::__unwrap_iter(__first),
+                                   _VSTD::__unwrap_iter(__last),
+                                   _VSTD::__unwrap_iter(__result)));
+    }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MOVE_BACKWARD_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/next_permutation.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/next_permutation.h
new file mode 100644
index 00000000000..1d71354eb37
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/next_permutation.h
@@ -0,0 +1,72 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_NEXT_PERMUTATION_H
+#define _LIBCPP___ALGORITHM_NEXT_PERMUTATION_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/reverse.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/swap.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _BidirectionalIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+__next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
+{
+    _BidirectionalIterator __i = __last;
+    if (__first == __last || __first == --__i)
+        return false;
+    while (true)
+    {
+        _BidirectionalIterator __ip1 = __i;
+        if (__comp(*--__i, *__ip1))
+        {
+            _BidirectionalIterator __j = __last;
+            while (!__comp(*__i, *--__j))
+                ;
+            swap(*__i, *__j);
+            _VSTD::reverse(__ip1, __last);
+            return true;
+        }
+        if (__i == __first)
+        {
+            _VSTD::reverse(__first, __last);
+            return false;
+        }
+    }
+}
+
+template <class _BidirectionalIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    return _VSTD::__next_permutation<_Comp_ref>(__first, __last, __comp);
+}
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
+{
+    return _VSTD::next_permutation(__first, __last,
+                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_NEXT_PERMUTATION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/none_of.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/none_of.h
new file mode 100644
index 00000000000..10339e2418c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/none_of.h
@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_NONE_OF_H
+#define _LIBCPP___ALGORITHM_NONE_OF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
+  for (; __first != __last; ++__first)
+    if (__pred(*__first))
+      return false;
+  return true;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_NONE_OF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/nth_element.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/nth_element.h
new file mode 100644
index 00000000000..bec6355ba9b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/nth_element.h
@@ -0,0 +1,239 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_NTH_ELEMENT_H
+#define _LIBCPP___ALGORITHM_NTH_ELEMENT_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/sort.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/swap.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _Compare, class _RandomAccessIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 bool
+__nth_element_find_guard(_RandomAccessIterator& __i, _RandomAccessIterator& __j,
+                         _RandomAccessIterator __m, _Compare __comp)
+{
+    // manually guard downward moving __j against __i
+    while (true) {
+        if (__i == --__j) {
+            return false;
+        }
+        if (__comp(*__j, *__m)) {
+            return true;  // found guard for downward moving __j, now use unguarded partition
+        }
+    }
+}
+
+template <class _Compare, class _RandomAccessIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 void
+__nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
+{
+    // _Compare is known to be a reference type
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    const difference_type __limit = 7;
+    while (true)
+    {
+        if (__nth == __last)
+            return;
+        difference_type __len = __last - __first;
+        switch (__len)
+        {
+        case 0:
+        case 1:
+            return;
+        case 2:
+            if (__comp(*--__last, *__first))
+                swap(*__first, *__last);
+            return;
+        case 3:
+            {
+            _RandomAccessIterator __m = __first;
+            _VSTD::__sort3<_Compare>(__first, ++__m, --__last, __comp);
+            return;
+            }
+        }
+        if (__len <= __limit)
+        {
+            _VSTD::__selection_sort<_Compare>(__first, __last, __comp);
+            return;
+        }
+        // __len > __limit >= 3
+        _RandomAccessIterator __m = __first + __len/2;
+        _RandomAccessIterator __lm1 = __last;
+        unsigned __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, --__lm1, __comp);
+        // *__m is median
+        // partition [__first, __m) < *__m and *__m <= [__m, __last)
+        // (this inhibits tossing elements equivalent to __m around unnecessarily)
+        _RandomAccessIterator __i = __first;
+        _RandomAccessIterator __j = __lm1;
+        // j points beyond range to be tested, *__lm1 is known to be <= *__m
+        // The search going up is known to be guarded but the search coming down isn't.
+        // Prime the downward search with a guard.
+        if (!__comp(*__i, *__m))  // if *__first == *__m
+        {
+            // *__first == *__m, *__first doesn't go in first part
+            if (_VSTD::__nth_element_find_guard<_Compare>(__i, __j, __m, __comp)) {
+                swap(*__i, *__j);
+                ++__n_swaps;
+            } else {
+                // *__first == *__m, *__m <= all other elements
+                // Partition instead into [__first, __i) == *__first and *__first < [__i, __last)
+                ++__i;  // __first + 1
+                __j = __last;
+                if (!__comp(*__first, *--__j)) {  // we need a guard if *__first == *(__last-1)
+                    while (true) {
+                        if (__i == __j) {
+                            return;  // [__first, __last) all equivalent elements
+                        } else if (__comp(*__first, *__i)) {
+                            swap(*__i, *__j);
+                            ++__n_swaps;
+                            ++__i;
+                            break;
+                        }
+                        ++__i;
+                    }
+                }
+                // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
+                if (__i == __j) {
+                    return;
+                }
+                while (true) {
+                    while (!__comp(*__first, *__i))
+                        ++__i;
+                    while (__comp(*__first, *--__j))
+                        ;
+                    if (__i >= __j)
+                        break;
+                    swap(*__i, *__j);
+                    ++__n_swaps;
+                    ++__i;
+                }
+                // [__first, __i) == *__first and *__first < [__i, __last)
+                // The first part is sorted,
+                if (__nth < __i) {
+                    return;
+                }
+                // __nth_element the second part
+                // _VSTD::__nth_element<_Compare>(__i, __nth, __last, __comp);
+                __first = __i;
+                continue;
+            }
+        }
+        ++__i;
+        // j points beyond range to be tested, *__lm1 is known to be <= *__m
+        // if not yet partitioned...
+        if (__i < __j)
+        {
+            // known that *(__i - 1) < *__m
+            while (true)
+            {
+                // __m still guards upward moving __i
+                while (__comp(*__i, *__m))
+                    ++__i;
+                // It is now known that a guard exists for downward moving __j
+                while (!__comp(*--__j, *__m))
+                    ;
+                if (__i >= __j)
+                    break;
+                swap(*__i, *__j);
+                ++__n_swaps;
+                // It is known that __m != __j
+                // If __m just moved, follow it
+                if (__m == __i)
+                    __m = __j;
+                ++__i;
+            }
+        }
+        // [__first, __i) < *__m and *__m <= [__i, __last)
+        if (__i != __m && __comp(*__m, *__i))
+        {
+            swap(*__i, *__m);
+            ++__n_swaps;
+        }
+        // [__first, __i) < *__i and *__i <= [__i+1, __last)
+        if (__nth == __i)
+            return;
+        if (__n_swaps == 0)
+        {
+            // We were given a perfectly partitioned sequence.  Coincidence?
+            if (__nth < __i)
+            {
+                // Check for [__first, __i) already sorted
+                __j = __m = __first;
+                while (true) {
+                    if (++__j == __i) {
+                        // [__first, __i) sorted
+                        return;
+                    }
+                    if (__comp(*__j, *__m)) {
+                        // not yet sorted, so sort
+                        break;
+                    }
+                    __m = __j;
+                }
+            }
+            else
+            {
+                // Check for [__i, __last) already sorted
+                __j = __m = __i;
+                while (true) {
+                    if (++__j == __last) {
+                        // [__i, __last) sorted
+                        return;
+                    }
+                    if (__comp(*__j, *__m)) {
+                        // not yet sorted, so sort
+                        break;
+                    }
+                    __m = __j;
+                }
+            }
+        }
+        // __nth_element on range containing __nth
+        if (__nth < __i)
+        {
+            // _VSTD::__nth_element<_Compare>(__first, __nth, __i, __comp);
+            __last = __i;
+        }
+        else
+        {
+            // _VSTD::__nth_element<_Compare>(__i+1, __nth, __last, __comp);
+            __first = ++__i;
+        }
+    }
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    _VSTD::__nth_element<_Comp_ref>(__first, __nth, __last, __comp);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last)
+{
+    _VSTD::nth_element(__first, __nth, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_NTH_ELEMENT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/partial_sort.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/partial_sort.h
new file mode 100644
index 00000000000..b1d2e1a79cb
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/partial_sort.h
@@ -0,0 +1,66 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PARTIAL_SORT_H
+#define _LIBCPP___ALGORITHM_PARTIAL_SORT_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/make_heap.h>
+#include <__algorithm/sift_down.h>
+#include <__algorithm/sort_heap.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/swap.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _RandomAccessIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 void
+__partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
+             _Compare __comp)
+{
+    _VSTD::__make_heap<_Compare>(__first, __middle, __comp);
+    typename iterator_traits<_RandomAccessIterator>::difference_type __len = __middle - __first;
+    for (_RandomAccessIterator __i = __middle; __i != __last; ++__i)
+    {
+        if (__comp(*__i, *__first))
+        {
+            swap(*__i, *__first);
+            _VSTD::__sift_down<_Compare>(__first, __middle, __comp, __len, __first);
+        }
+    }
+    _VSTD::__sort_heap<_Compare>(__first, __middle, __comp);
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
+             _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    _VSTD::__partial_sort<_Comp_ref>(__first, __middle, __last, __comp);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
+{
+    _VSTD::partial_sort(__first, __middle, __last,
+                       __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PARTIAL_SORT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/partial_sort_copy.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/partial_sort_copy.h
new file mode 100644
index 00000000000..4c0c9f5ad04
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/partial_sort_copy.h
@@ -0,0 +1,72 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PARTIAL_SORT_COPY_H
+#define _LIBCPP___ALGORITHM_PARTIAL_SORT_COPY_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/make_heap.h>
+#include <__algorithm/sift_down.h>
+#include <__algorithm/sort_heap.h>
+#include <__iterator/iterator_traits.h>
+#include <type_traits> // swap
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _InputIterator, class _RandomAccessIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _RandomAccessIterator
+__partial_sort_copy(_InputIterator __first, _InputIterator __last,
+                    _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
+{
+    _RandomAccessIterator __r = __result_first;
+    if (__r != __result_last)
+    {
+        for (; __first != __last && __r != __result_last; ++__first, (void) ++__r)
+            *__r = *__first;
+        _VSTD::__make_heap<_Compare>(__result_first, __r, __comp);
+        typename iterator_traits<_RandomAccessIterator>::difference_type __len = __r - __result_first;
+        for (; __first != __last; ++__first)
+            if (__comp(*__first, *__result_first))
+            {
+                *__result_first = *__first;
+                _VSTD::__sift_down<_Compare>(__result_first, __r, __comp, __len, __result_first);
+            }
+        _VSTD::__sort_heap<_Compare>(__result_first, __r, __comp);
+    }
+    return __r;
+}
+
+template <class _InputIterator, class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_RandomAccessIterator
+partial_sort_copy(_InputIterator __first, _InputIterator __last,
+                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    return _VSTD::__partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __comp);
+}
+
+template <class _InputIterator, class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_RandomAccessIterator
+partial_sort_copy(_InputIterator __first, _InputIterator __last,
+                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last)
+{
+    return _VSTD::partial_sort_copy(__first, __last, __result_first, __result_last,
+                                   __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PARTIAL_SORT_COPY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/partition.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/partition.h
new file mode 100644
index 00000000000..2614520ccbc
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/partition.h
@@ -0,0 +1,82 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PARTITION_H
+#define _LIBCPP___ALGORITHM_PARTITION_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__utility/swap.h>
+#include <utility> // pair
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Predicate, class _ForwardIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+__partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, forward_iterator_tag)
+{
+    while (true)
+    {
+        if (__first == __last)
+            return __first;
+        if (!__pred(*__first))
+            break;
+        ++__first;
+    }
+    for (_ForwardIterator __p = __first; ++__p != __last;)
+    {
+        if (__pred(*__p))
+        {
+            swap(*__first, *__p);
+            ++__first;
+        }
+    }
+    return __first;
+}
+
+template <class _Predicate, class _BidirectionalIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _BidirectionalIterator
+__partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
+            bidirectional_iterator_tag)
+{
+    while (true)
+    {
+        while (true)
+        {
+            if (__first == __last)
+                return __first;
+            if (!__pred(*__first))
+                break;
+            ++__first;
+        }
+        do
+        {
+            if (__first == --__last)
+                return __first;
+        } while (!__pred(*__last));
+        swap(*__first, *__last);
+        ++__first;
+    }
+}
+
+template <class _ForwardIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator
+partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    return _VSTD::__partition<_Predicate&>(
+        __first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PARTITION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/partition_copy.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/partition_copy.h
new file mode 100644
index 00000000000..d34944589b9
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/partition_copy.h
@@ -0,0 +1,47 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PARTITION_COPY_H
+#define _LIBCPP___ALGORITHM_PARTITION_COPY_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <utility> // pair
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _OutputIterator1,
+          class _OutputIterator2, class _Predicate>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 pair<_OutputIterator1, _OutputIterator2>
+partition_copy(_InputIterator __first, _InputIterator __last,
+               _OutputIterator1 __out_true, _OutputIterator2 __out_false,
+               _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+    {
+        if (__pred(*__first))
+        {
+            *__out_true = *__first;
+            ++__out_true;
+        }
+        else
+        {
+            *__out_false = *__first;
+            ++__out_false;
+        }
+    }
+    return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PARTITION_COPY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/partition_point.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/partition_point.h
new file mode 100644
index 00000000000..33aaf33d938
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/partition_point.h
@@ -0,0 +1,46 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PARTITION_POINT_H
+#define _LIBCPP___ALGORITHM_PARTITION_POINT_H
+
+#include <__config>
+#include <__algorithm/half_positive.h>
+#include <iterator>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _ForwardIterator, class _Predicate>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
+    difference_type __len = _VSTD::distance(__first, __last);
+    while (__len != 0)
+    {
+        difference_type __l2 = _VSTD::__half_positive(__len);
+        _ForwardIterator __m = __first;
+        _VSTD::advance(__m, __l2);
+        if (__pred(*__m))
+        {
+            __first = ++__m;
+            __len -= __l2 + 1;
+        }
+        else
+            __len = __l2;
+    }
+    return __first;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PARTITION_POINT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/pop_heap.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/pop_heap.h
new file mode 100644
index 00000000000..e8c801a5c81
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/pop_heap.h
@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_POP_HEAP_H
+#define _LIBCPP___ALGORITHM_POP_HEAP_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/sift_down.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/swap.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+__pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+           typename iterator_traits<_RandomAccessIterator>::difference_type __len)
+{
+    if (__len > 1)
+    {
+        swap(*__first, *--__last);
+        _VSTD::__sift_down<_Compare>(__first, __last, __comp, __len - 1, __first);
+    }
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    _VSTD::__pop_heap<_Comp_ref>(__first, __last, __comp, __last - __first);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    _VSTD::pop_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_POP_HEAP_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/prev_permutation.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/prev_permutation.h
new file mode 100644
index 00000000000..12c1816da37
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/prev_permutation.h
@@ -0,0 +1,72 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PREV_PERMUTATION_H
+#define _LIBCPP___ALGORITHM_PREV_PERMUTATION_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/reverse.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/swap.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _BidirectionalIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+__prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
+{
+    _BidirectionalIterator __i = __last;
+    if (__first == __last || __first == --__i)
+        return false;
+    while (true)
+    {
+        _BidirectionalIterator __ip1 = __i;
+        if (__comp(*__ip1, *--__i))
+        {
+            _BidirectionalIterator __j = __last;
+            while (!__comp(*--__j, *__i))
+                ;
+            swap(*__i, *__j);
+            _VSTD::reverse(__ip1, __last);
+            return true;
+        }
+        if (__i == __first)
+        {
+            _VSTD::reverse(__first, __last);
+            return false;
+        }
+    }
+}
+
+template <class _BidirectionalIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    return _VSTD::__prev_permutation<_Comp_ref>(__first, __last, __comp);
+}
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool
+prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
+{
+    return _VSTD::prev_permutation(__first, __last,
+                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PREV_PERMUTATION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/push_heap.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/push_heap.h
new file mode 100644
index 00000000000..9327fe05b51
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/push_heap.h
@@ -0,0 +1,70 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PUSH_HEAP_H
+#define _LIBCPP___ALGORITHM_PUSH_HEAP_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _RandomAccessIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 void
+__sift_up(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+          typename iterator_traits<_RandomAccessIterator>::difference_type __len)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    if (__len > 1)
+    {
+        __len = (__len - 2) / 2;
+        _RandomAccessIterator __ptr = __first + __len;
+        if (__comp(*__ptr, *--__last))
+        {
+            value_type __t(_VSTD::move(*__last));
+            do
+            {
+                *__last = _VSTD::move(*__ptr);
+                __last = __ptr;
+                if (__len == 0)
+                    break;
+                __len = (__len - 1) / 2;
+                __ptr = __first + __len;
+            } while (__comp(*__ptr, __t));
+            *__last = _VSTD::move(__t);
+        }
+    }
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    _VSTD::__sift_up<_Comp_ref>(__first, __last, __comp, __last - __first);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    _VSTD::push_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PUSH_HEAP_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/remove.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/remove.h
new file mode 100644
index 00000000000..171d83284a2
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/remove.h
@@ -0,0 +1,45 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_REMOVE_H
+#define _LIBCPP___ALGORITHM_REMOVE_H
+
+#include <__config>
+#include <__algorithm/find.h>
+#include <__algorithm/find_if.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Tp>
+_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+remove(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
+{
+    __first = _VSTD::find(__first, __last, __value_);
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+        {
+            if (!(*__i == __value_))
+            {
+                *__first = _VSTD::move(*__i);
+                ++__first;
+            }
+        }
+    }
+    return __first;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_REMOVE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/remove_copy.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/remove_copy.h
new file mode 100644
index 00000000000..338ca94300b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/remove_copy.h
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_REMOVE_COPY_H
+#define _LIBCPP___ALGORITHM_REMOVE_COPY_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _OutputIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+remove_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, const _Tp& __value_)
+{
+    for (; __first != __last; ++__first)
+    {
+        if (!(*__first == __value_))
+        {
+            *__result = *__first;
+            ++__result;
+        }
+    }
+    return __result;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_REMOVE_COPY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/remove_copy_if.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/remove_copy_if.h
new file mode 100644
index 00000000000..a5563872207
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/remove_copy_if.h
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_REMOVE_COPY_IF_H
+#define _LIBCPP___ALGORITHM_REMOVE_COPY_IF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _OutputIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+remove_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+    {
+        if (!__pred(*__first))
+        {
+            *__result = *__first;
+            ++__result;
+        }
+    }
+    return __result;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_REMOVE_COPY_IF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/remove_if.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/remove_if.h
new file mode 100644
index 00000000000..4df36896afd
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/remove_if.h
@@ -0,0 +1,44 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_REMOVE_IF_H
+#define _LIBCPP___ALGORITHM_REMOVE_IF_H
+
+#include <__config>
+#include <__algorithm/find_if.h>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+remove_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    __first = _VSTD::find_if<_ForwardIterator, _Predicate&>(__first, __last, __pred);
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+        {
+            if (!__pred(*__i))
+            {
+                *__first = _VSTD::move(*__i);
+                ++__first;
+            }
+        }
+    }
+    return __first;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_REMOVE_IF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/replace.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/replace.h
new file mode 100644
index 00000000000..2bc96ffc87d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/replace.h
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_REPLACE_H
+#define _LIBCPP___ALGORITHM_REPLACE_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+replace(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __old_value, const _Tp& __new_value)
+{
+    for (; __first != __last; ++__first)
+        if (*__first == __old_value)
+            *__first = __new_value;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_REPLACE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/replace_copy.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/replace_copy.h
new file mode 100644
index 00000000000..c6c5fe32e81
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/replace_copy.h
@@ -0,0 +1,36 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_REPLACE_COPY_H
+#define _LIBCPP___ALGORITHM_REPLACE_COPY_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _OutputIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+replace_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
+             const _Tp& __old_value, const _Tp& __new_value)
+{
+    for (; __first != __last; ++__first, (void) ++__result)
+        if (*__first == __old_value)
+            *__result = __new_value;
+        else
+            *__result = *__first;
+    return __result;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_REPLACE_COPY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/replace_copy_if.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/replace_copy_if.h
new file mode 100644
index 00000000000..274d8e630ef
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/replace_copy_if.h
@@ -0,0 +1,36 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_REPLACE_COPY_IF_H
+#define _LIBCPP___ALGORITHM_REPLACE_COPY_IF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _OutputIterator, class _Predicate, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+replace_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
+                _Predicate __pred, const _Tp& __new_value)
+{
+    for (; __first != __last; ++__first, (void) ++__result)
+        if (__pred(*__first))
+            *__result = __new_value;
+        else
+            *__result = *__first;
+    return __result;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_REPLACE_COPY_IF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/replace_if.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/replace_if.h
new file mode 100644
index 00000000000..bcc3feb2f50
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/replace_if.h
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_REPLACE_IF_H
+#define _LIBCPP___ALGORITHM_REPLACE_IF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Predicate, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+replace_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, const _Tp& __new_value)
+{
+    for (; __first != __last; ++__first)
+        if (__pred(*__first))
+            *__first = __new_value;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_REPLACE_IF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/reverse.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/reverse.h
new file mode 100644
index 00000000000..28bd2e84c8a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/reverse.h
@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_REVERSE_H
+#define _LIBCPP___ALGORITHM_REVERSE_H
+
+#include <__config>
+#include <__algorithm/iter_swap.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+__reverse(_BidirectionalIterator __first, _BidirectionalIterator __last, bidirectional_iterator_tag)
+{
+    while (__first != __last)
+    {
+        if (__first == --__last)
+            break;
+        _VSTD::iter_swap(__first, __last);
+        ++__first;
+    }
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+__reverse(_RandomAccessIterator __first, _RandomAccessIterator __last, random_access_iterator_tag)
+{
+    if (__first != __last)
+        for (; __first < --__last; ++__first)
+            _VSTD::iter_swap(__first, __last);
+}
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)
+{
+    _VSTD::__reverse(__first, __last, typename iterator_traits<_BidirectionalIterator>::iterator_category());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_REVERSE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/reverse_copy.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/reverse_copy.h
new file mode 100644
index 00000000000..002c0344a79
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/reverse_copy.h
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_REVERSE_COPY_H
+#define _LIBCPP___ALGORITHM_REVERSE_COPY_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _BidirectionalIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
+{
+    for (; __first != __last; ++__result)
+        *__result = *--__last;
+    return __result;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_REVERSE_COPY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/rotate.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/rotate.h
new file mode 100644
index 00000000000..fd6d3e9c114
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/rotate.h
@@ -0,0 +1,200 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_ROTATE_H
+#define _LIBCPP___ALGORITHM_ROTATE_H
+
+#include <__algorithm/move.h>
+#include <__algorithm/move_backward.h>
+#include <__algorithm/swap_ranges.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
+#include <__iterator/prev.h>
+#include <__utility/swap.h>
+#include <iterator>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _ForwardIterator
+__rotate_left(_ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
+    value_type __tmp = _VSTD::move(*__first);
+    _ForwardIterator __lm1 = _VSTD::move(_VSTD::next(__first), __last, __first);
+    *__lm1 = _VSTD::move(__tmp);
+    return __lm1;
+}
+
+template <class _BidirectionalIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _BidirectionalIterator
+__rotate_right(_BidirectionalIterator __first, _BidirectionalIterator __last)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    _BidirectionalIterator __lm1 = _VSTD::prev(__last);
+    value_type __tmp = _VSTD::move(*__lm1);
+    _BidirectionalIterator __fp1 = _VSTD::move_backward(__first, __lm1, __last);
+    *__first = _VSTD::move(__tmp);
+    return __fp1;
+}
+
+template <class _ForwardIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX14 _ForwardIterator
+__rotate_forward(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
+{
+    _ForwardIterator __i = __middle;
+    while (true)
+    {
+        swap(*__first, *__i);
+        ++__first;
+        if (++__i == __last)
+            break;
+        if (__first == __middle)
+            __middle = __i;
+    }
+    _ForwardIterator __r = __first;
+    if (__first != __middle)
+    {
+        __i = __middle;
+        while (true)
+        {
+            swap(*__first, *__i);
+            ++__first;
+            if (++__i == __last)
+            {
+                if (__first == __middle)
+                    break;
+                __i = __middle;
+            }
+            else if (__first == __middle)
+                __middle = __i;
+        }
+    }
+    return __r;
+}
+
+template<typename _Integral>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX14 _Integral
+__algo_gcd(_Integral __x, _Integral __y)
+{
+    do
+    {
+        _Integral __t = __x % __y;
+        __x = __y;
+        __y = __t;
+    } while (__y);
+    return __x;
+}
+
+template<typename _RandomAccessIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX14 _RandomAccessIterator
+__rotate_gcd(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+
+    const difference_type __m1 = __middle - __first;
+    const difference_type __m2 = __last - __middle;
+    if (__m1 == __m2)
+    {
+        _VSTD::swap_ranges(__first, __middle, __middle);
+        return __middle;
+    }
+    const difference_type __g = _VSTD::__algo_gcd(__m1, __m2);
+    for (_RandomAccessIterator __p = __first + __g; __p != __first;)
+    {
+        value_type __t(_VSTD::move(*--__p));
+        _RandomAccessIterator __p1 = __p;
+        _RandomAccessIterator __p2 = __p1 + __m1;
+        do
+        {
+            *__p1 = _VSTD::move(*__p2);
+            __p1 = __p2;
+            const difference_type __d = __last - __p2;
+            if (__m1 < __d)
+                __p2 += __m1;
+            else
+                __p2 = __first + (__m1 - __d);
+        } while (__p2 != __p);
+        *__p1 = _VSTD::move(__t);
+    }
+    return __first + __m2;
+}
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _ForwardIterator
+__rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last,
+         _VSTD::forward_iterator_tag)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
+    if (is_trivially_move_assignable<value_type>::value)
+    {
+        if (_VSTD::next(__first) == __middle)
+            return _VSTD::__rotate_left(__first, __last);
+    }
+    return _VSTD::__rotate_forward(__first, __middle, __last);
+}
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _BidirectionalIterator
+__rotate(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
+         bidirectional_iterator_tag)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    if (is_trivially_move_assignable<value_type>::value)
+    {
+        if (_VSTD::next(__first) == __middle)
+            return _VSTD::__rotate_left(__first, __last);
+        if (_VSTD::next(__middle) == __last)
+            return _VSTD::__rotate_right(__first, __last);
+    }
+    return _VSTD::__rotate_forward(__first, __middle, __last);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _RandomAccessIterator
+__rotate(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
+         random_access_iterator_tag)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    if (is_trivially_move_assignable<value_type>::value)
+    {
+        if (_VSTD::next(__first) == __middle)
+            return _VSTD::__rotate_left(__first, __last);
+        if (_VSTD::next(__middle) == __last)
+            return _VSTD::__rotate_right(__first, __last);
+        return _VSTD::__rotate_gcd(__first, __middle, __last);
+    }
+    return _VSTD::__rotate_forward(__first, __middle, __last);
+}
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
+{
+    if (__first == __middle)
+        return __last;
+    if (__middle == __last)
+        return __first;
+    return _VSTD::__rotate(__first, __middle, __last,
+                           typename iterator_traits<_ForwardIterator>::iterator_category());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_ROTATE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/rotate_copy.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/rotate_copy.h
new file mode 100644
index 00000000000..4c682ef93d5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/rotate_copy.h
@@ -0,0 +1,33 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_ROTATE_COPY_H
+#define _LIBCPP___ALGORITHM_ROTATE_COPY_H
+
+#include <__config>
+#include <__algorithm/copy.h>
+#include <iterator>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+rotate_copy(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last, _OutputIterator __result)
+{
+    return _VSTD::copy(__first, __middle, _VSTD::copy(__middle, __last, __result));
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_ROTATE_COPY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/sample.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/sample.h
new file mode 100644
index 00000000000..33264c4ea3a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/sample.h
@@ -0,0 +1,102 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SAMPLE_H
+#define _LIBCPP___ALGORITHM_SAMPLE_H
+
+#include <__algorithm/min.h>
+#include <__config>
+#include <__debug>
+#include <__random/uniform_int_distribution.h>
+#include <iterator>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _PopulationIterator, class _SampleIterator, class _Distance,
+          class _UniformRandomNumberGenerator>
+_LIBCPP_INLINE_VISIBILITY
+_SampleIterator __sample(_PopulationIterator __first,
+                         _PopulationIterator __last, _SampleIterator __output_iter,
+                         _Distance __n,
+                         _UniformRandomNumberGenerator & __g,
+                         input_iterator_tag) {
+
+  _Distance __k = 0;
+  for (; __first != __last && __k < __n; ++__first, (void) ++__k)
+    __output_iter[__k] = *__first;
+  _Distance __sz = __k;
+  for (; __first != __last; ++__first, (void) ++__k) {
+    _Distance __r = uniform_int_distribution<_Distance>(0, __k)(__g);
+    if (__r < __sz)
+      __output_iter[__r] = *__first;
+  }
+  return __output_iter + _VSTD::min(__n, __k);
+}
+
+template <class _PopulationIterator, class _SampleIterator, class _Distance,
+          class _UniformRandomNumberGenerator>
+_LIBCPP_INLINE_VISIBILITY
+_SampleIterator __sample(_PopulationIterator __first,
+                         _PopulationIterator __last, _SampleIterator __output_iter,
+                         _Distance __n,
+                         _UniformRandomNumberGenerator& __g,
+                         forward_iterator_tag) {
+  _Distance __unsampled_sz = _VSTD::distance(__first, __last);
+  for (__n = _VSTD::min(__n, __unsampled_sz); __n != 0; ++__first) {
+    _Distance __r = uniform_int_distribution<_Distance>(0, --__unsampled_sz)(__g);
+    if (__r < __n) {
+      *__output_iter++ = *__first;
+      --__n;
+    }
+  }
+  return __output_iter;
+}
+
+template <class _PopulationIterator, class _SampleIterator, class _Distance,
+          class _UniformRandomNumberGenerator>
+_LIBCPP_INLINE_VISIBILITY
+_SampleIterator __sample(_PopulationIterator __first,
+                         _PopulationIterator __last, _SampleIterator __output_iter,
+                         _Distance __n, _UniformRandomNumberGenerator& __g) {
+  typedef typename iterator_traits<_PopulationIterator>::iterator_category
+        _PopCategory;
+  typedef typename iterator_traits<_PopulationIterator>::difference_type
+        _Difference;
+  static_assert(__is_cpp17_forward_iterator<_PopulationIterator>::value ||
+                __is_cpp17_random_access_iterator<_SampleIterator>::value,
+                "SampleIterator must meet the requirements of RandomAccessIterator");
+  typedef typename common_type<_Distance, _Difference>::type _CommonType;
+  _LIBCPP_ASSERT(__n >= 0, "N must be a positive number.");
+  return _VSTD::__sample(
+      __first, __last, __output_iter, _CommonType(__n),
+      __g, _PopCategory());
+}
+
+#if _LIBCPP_STD_VER > 14
+template <class _PopulationIterator, class _SampleIterator, class _Distance,
+          class _UniformRandomNumberGenerator>
+inline _LIBCPP_INLINE_VISIBILITY
+_SampleIterator sample(_PopulationIterator __first,
+                       _PopulationIterator __last, _SampleIterator __output_iter,
+                       _Distance __n, _UniformRandomNumberGenerator&& __g) {
+    return _VSTD::__sample(__first, __last, __output_iter, __n, __g);
+}
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_SAMPLE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/search.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/search.h
new file mode 100644
index 00000000000..367a5bf1c89
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/search.h
@@ -0,0 +1,125 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SEARCH_H
+#define _LIBCPP___ALGORITHM_SEARCH_H
+
+#include <__algorithm/comp.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
+pair<_ForwardIterator1, _ForwardIterator1>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                                           _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+                                           _BinaryPredicate __pred, forward_iterator_tag, forward_iterator_tag) {
+  if (__first2 == __last2)
+    return _VSTD::make_pair(__first1, __first1); // Everything matches an empty sequence
+  while (true) {
+    // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks
+    while (true) {
+      if (__first1 == __last1) // return __last1 if no element matches *__first2
+        return _VSTD::make_pair(__last1, __last1);
+      if (__pred(*__first1, *__first2))
+        break;
+      ++__first1;
+    }
+    // *__first1 matches *__first2, now match elements after here
+    _ForwardIterator1 __m1 = __first1;
+    _ForwardIterator2 __m2 = __first2;
+    while (true) {
+      if (++__m2 == __last2) // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
+        return _VSTD::make_pair(__first1, __m1);
+      if (++__m1 == __last1) // Otherwise if source exhaused, pattern not found
+        return _VSTD::make_pair(__last1, __last1);
+      if (!__pred(*__m1, *__m2)) // if there is a mismatch, restart with a new __first1
+      {
+        ++__first1;
+        break;
+      } // else there is a match, check next elements
+    }
+  }
+}
+
+template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 pair<_RandomAccessIterator1, _RandomAccessIterator1>
+__search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+         _RandomAccessIterator2 __last2, _BinaryPredicate __pred, random_access_iterator_tag,
+         random_access_iterator_tag) {
+  typedef typename iterator_traits<_RandomAccessIterator1>::difference_type _D1;
+  typedef typename iterator_traits<_RandomAccessIterator2>::difference_type _D2;
+  // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
+  const _D2 __len2 = __last2 - __first2;
+  if (__len2 == 0)
+    return _VSTD::make_pair(__first1, __first1);
+  const _D1 __len1 = __last1 - __first1;
+  if (__len1 < __len2)
+    return _VSTD::make_pair(__last1, __last1);
+  const _RandomAccessIterator1 __s = __last1 - (__len2 - 1); // Start of pattern match can't go beyond here
+
+  while (true) {
+    while (true) {
+      if (__first1 == __s)
+        return _VSTD::make_pair(__last1, __last1);
+      if (__pred(*__first1, *__first2))
+        break;
+      ++__first1;
+    }
+
+    _RandomAccessIterator1 __m1 = __first1;
+    _RandomAccessIterator2 __m2 = __first2;
+    while (true) {
+      if (++__m2 == __last2)
+        return _VSTD::make_pair(__first1, __first1 + __len2);
+      ++__m1; // no need to check range on __m1 because __s guarantees we have enough source
+      if (!__pred(*__m1, *__m2)) {
+        ++__first1;
+        break;
+      }
+    }
+  }
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1
+search(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+       _BinaryPredicate __pred) {
+  return _VSTD::__search<_BinaryPredicate&>(
+             __first1, __last1, __first2, __last2, __pred,
+             typename iterator_traits<_ForwardIterator1>::iterator_category(),
+             typename iterator_traits<_ForwardIterator2>::iterator_category()).first;
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1
+search(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
+  typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
+  typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
+  return _VSTD::search(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
+}
+
+#if _LIBCPP_STD_VER > 14
+template <class _ForwardIterator, class _Searcher>
+_LIBCPP_NODISCARD_EXT _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+search(_ForwardIterator __f, _ForwardIterator __l, const _Searcher& __s) {
+  return __s(__f, __l).first;
+}
+
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_SEARCH_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/search_n.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/search_n.h
new file mode 100644
index 00000000000..663edb37b41
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/search_n.h
@@ -0,0 +1,111 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SEARCH_N_H
+#define _LIBCPP___ALGORITHM_SEARCH_N_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__iterator/iterator_traits.h>
+#include <type_traits>  // __convert_to_integral
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _BinaryPredicate, class _ForwardIterator, class _Size, class _Tp>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator __search_n(_ForwardIterator __first, _ForwardIterator __last,
+                                                          _Size __count, const _Tp& __value_, _BinaryPredicate __pred,
+                                                          forward_iterator_tag) {
+  if (__count <= 0)
+    return __first;
+  while (true) {
+    // Find first element in sequence that matchs __value_, with a mininum of loop checks
+    while (true) {
+      if (__first == __last) // return __last if no element matches __value_
+        return __last;
+      if (__pred(*__first, __value_))
+        break;
+      ++__first;
+    }
+    // *__first matches __value_, now match elements after here
+    _ForwardIterator __m = __first;
+    _Size __c(0);
+    while (true) {
+      if (++__c == __count) // If pattern exhausted, __first is the answer (works for 1 element pattern)
+        return __first;
+      if (++__m == __last) // Otherwise if source exhaused, pattern not found
+        return __last;
+      if (!__pred(*__m, __value_)) // if there is a mismatch, restart with a new __first
+      {
+        __first = __m;
+        ++__first;
+        break;
+      } // else there is a match, check next elements
+    }
+  }
+}
+
+template <class _BinaryPredicate, class _RandomAccessIterator, class _Size, class _Tp>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _RandomAccessIterator __search_n(_RandomAccessIterator __first,
+                                                               _RandomAccessIterator __last, _Size __count,
+                                                               const _Tp& __value_, _BinaryPredicate __pred,
+                                                               random_access_iterator_tag) {
+  if (__count <= 0)
+    return __first;
+  _Size __len = static_cast<_Size>(__last - __first);
+  if (__len < __count)
+    return __last;
+  const _RandomAccessIterator __s = __last - (__count - 1); // Start of pattern match can't go beyond here
+  while (true) {
+    // Find first element in sequence that matchs __value_, with a mininum of loop checks
+    while (true) {
+      if (__first >= __s) // return __last if no element matches __value_
+        return __last;
+      if (__pred(*__first, __value_))
+        break;
+      ++__first;
+    }
+    // *__first matches __value_, now match elements after here
+    _RandomAccessIterator __m = __first;
+    _Size __c(0);
+    while (true) {
+      if (++__c == __count) // If pattern exhausted, __first is the answer (works for 1 element pattern)
+        return __first;
+      ++__m;                       // no need to check range on __m because __s guarantees we have enough source
+      if (!__pred(*__m, __value_)) // if there is a mismatch, restart with a new __first
+      {
+        __first = __m;
+        ++__first;
+        break;
+      } // else there is a match, check next elements
+    }
+  }
+}
+
+template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator search_n(
+    _ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value_, _BinaryPredicate __pred) {
+  return _VSTD::__search_n<_BinaryPredicate&>(
+      __first, __last, _VSTD::__convert_to_integral(__count), __value_, __pred,
+      typename iterator_traits<_ForwardIterator>::iterator_category());
+}
+
+template <class _ForwardIterator, class _Size, class _Tp>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value_) {
+  typedef typename iterator_traits<_ForwardIterator>::value_type __v;
+  return _VSTD::search_n(__first, __last, _VSTD::__convert_to_integral(__count), __value_, __equal_to<__v, _Tp>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_SEARCH_N_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/set_difference.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/set_difference.h
new file mode 100644
index 00000000000..d4a9750d6dd
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/set_difference.h
@@ -0,0 +1,72 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SET_DIFFERENCE_H
+#define _LIBCPP___ALGORITHM_SET_DIFFERENCE_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/copy.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator
+__set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    while (__first1 != __last1)
+    {
+        if (__first2 == __last2)
+            return _VSTD::copy(__first1, __last1, __result);
+        if (__comp(*__first1, *__first2))
+        {
+            *__result = *__first1;
+            ++__result;
+            ++__first1;
+        }
+        else
+        {
+            if (!__comp(*__first2, *__first1))
+                ++__first1;
+            ++__first2;
+        }
+    }
+    return __result;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    return _VSTD::__set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
+{
+    return _VSTD::set_difference(__first1, __last1, __first2, __last2, __result,
+                                __less<typename iterator_traits<_InputIterator1>::value_type,
+                                       typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_SET_DIFFERENCE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/set_intersection.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/set_intersection.h
new file mode 100644
index 00000000000..518e5e68b39
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/set_intersection.h
@@ -0,0 +1,69 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SET_INTERSECTION_H
+#define _LIBCPP___ALGORITHM_SET_INTERSECTION_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator
+__set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
+                   _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    while (__first1 != __last1 && __first2 != __last2)
+    {
+        if (__comp(*__first1, *__first2))
+            ++__first1;
+        else
+        {
+            if (!__comp(*__first2, *__first1))
+            {
+                *__result = *__first1;
+                ++__result;
+                ++__first1;
+            }
+            ++__first2;
+        }
+    }
+    return __result;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
+                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    return _VSTD::__set_intersection<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
+                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
+{
+    return _VSTD::set_intersection(__first1, __last1, __first2, __last2, __result,
+                                  __less<typename iterator_traits<_InputIterator1>::value_type,
+                                         typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_SET_INTERSECTION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/set_symmetric_difference.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/set_symmetric_difference.h
new file mode 100644
index 00000000000..efdf6272570
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/set_symmetric_difference.h
@@ -0,0 +1,77 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SET_SYMMETRIC_DIFFERENCE_H
+#define _LIBCPP___ALGORITHM_SET_SYMMETRIC_DIFFERENCE_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/copy.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator
+__set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+                           _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    while (__first1 != __last1)
+    {
+        if (__first2 == __last2)
+            return _VSTD::copy(__first1, __last1, __result);
+        if (__comp(*__first1, *__first2))
+        {
+            *__result = *__first1;
+            ++__result;
+            ++__first1;
+        }
+        else
+        {
+            if (__comp(*__first2, *__first1))
+            {
+                *__result = *__first2;
+                ++__result;
+            }
+            else
+                ++__first1;
+            ++__first2;
+        }
+    }
+    return _VSTD::copy(__first2, __last2, __result);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    return _VSTD::__set_symmetric_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
+                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
+{
+    return _VSTD::set_symmetric_difference(__first1, __last1, __first2, __last2, __result,
+                                          __less<typename iterator_traits<_InputIterator1>::value_type,
+                                                 typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_SET_SYMMETRIC_DIFFERENCE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/set_union.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/set_union.h
new file mode 100644
index 00000000000..388f037a73a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/set_union.h
@@ -0,0 +1,72 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SET_UNION_H
+#define _LIBCPP___ALGORITHM_SET_UNION_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/copy.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator
+__set_union(_InputIterator1 __first1, _InputIterator1 __last1,
+            _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    for (; __first1 != __last1; ++__result)
+    {
+        if (__first2 == __last2)
+            return _VSTD::copy(__first1, __last1, __result);
+        if (__comp(*__first2, *__first1))
+        {
+            *__result = *__first2;
+            ++__first2;
+        }
+        else
+        {
+            if (!__comp(*__first1, *__first2))
+                ++__first2;
+            *__result = *__first1;
+            ++__first1;
+        }
+    }
+    return _VSTD::copy(__first2, __last2, __result);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+set_union(_InputIterator1 __first1, _InputIterator1 __last1,
+          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    return _VSTD::__set_union<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+set_union(_InputIterator1 __first1, _InputIterator1 __last1,
+          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
+{
+    return _VSTD::set_union(__first1, __last1, __first2, __last2, __result,
+                          __less<typename iterator_traits<_InputIterator1>::value_type,
+                                 typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_SET_UNION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/shift_left.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/shift_left.h
new file mode 100644
index 00000000000..8d9bc07d2e4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/shift_left.h
@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SHIFT_LEFT_H
+#define _LIBCPP___ALGORITHM_SHIFT_LEFT_H
+
+#include <__config>
+#include <__algorithm/move.h>
+#include <__iterator/iterator_traits.h>
+#include <type_traits> // swap
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY constexpr
+_ForwardIterator
+shift_left(_ForwardIterator __first, _ForwardIterator __last,
+           typename iterator_traits<_ForwardIterator>::difference_type __n)
+{
+    if (__n == 0) {
+        return __last;
+    }
+
+    _ForwardIterator __m = __first;
+    if constexpr (__is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+        if (__n >= __last - __first) {
+            return __first;
+        }
+        __m += __n;
+    } else {
+        for (; __n > 0; --__n) {
+            if (__m == __last) {
+                return __first;
+            }
+            ++__m;
+        }
+    }
+    return _VSTD::move(__m, __last, __first);
+}
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_SHIFT_LEFT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/shift_right.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/shift_right.h
new file mode 100644
index 00000000000..cee17733a6a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/shift_right.h
@@ -0,0 +1,101 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SHIFT_RIGHT_H
+#define _LIBCPP___ALGORITHM_SHIFT_RIGHT_H
+
+#include <__config>
+#include <__algorithm/move.h>
+#include <__algorithm/move_backward.h>
+#include <__algorithm/swap_ranges.h>
+#include <__iterator/iterator_traits.h>
+#include <type_traits> // swap
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY constexpr
+_ForwardIterator
+shift_right(_ForwardIterator __first, _ForwardIterator __last,
+            typename iterator_traits<_ForwardIterator>::difference_type __n)
+{
+    if (__n == 0) {
+        return __first;
+    }
+
+    if constexpr (__is_cpp17_random_access_iterator<_ForwardIterator>::value) {
+        decltype(__n) __d = __last - __first;
+        if (__n >= __d) {
+            return __last;
+        }
+        _ForwardIterator __m = __first + (__d - __n);
+        return _VSTD::move_backward(__first, __m, __last);
+    } else if constexpr (__is_cpp17_bidirectional_iterator<_ForwardIterator>::value) {
+        _ForwardIterator __m = __last;
+        for (; __n > 0; --__n) {
+            if (__m == __first) {
+                return __last;
+            }
+            --__m;
+        }
+        return _VSTD::move_backward(__first, __m, __last);
+    } else {
+        _ForwardIterator __ret = __first;
+        for (; __n > 0; --__n) {
+            if (__ret == __last) {
+                return __last;
+            }
+            ++__ret;
+        }
+
+        // We have an __n-element scratch space from __first to __ret.
+        // Slide an __n-element window [__trail, __lead) from left to right.
+        // We're essentially doing swap_ranges(__first, __ret, __trail, __lead)
+        // over and over; but once __lead reaches __last we needn't bother
+        // to save the values of elements [__trail, __last).
+
+        auto __trail = __first;
+        auto __lead = __ret;
+        while (__trail != __ret) {
+            if (__lead == __last) {
+                _VSTD::move(__first, __trail, __ret);
+                return __ret;
+            }
+            ++__trail;
+            ++__lead;
+        }
+
+        _ForwardIterator __mid = __first;
+        while (true) {
+            if (__lead == __last) {
+                __trail = _VSTD::move(__mid, __ret, __trail);
+                _VSTD::move(__first, __mid, __trail);
+                return __ret;
+            }
+            swap(*__mid, *__trail);
+            ++__mid;
+            ++__trail;
+            ++__lead;
+            if (__mid == __ret) {
+                __mid = __first;
+            }
+        }
+    }
+}
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_SHIFT_RIGHT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/shuffle.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/shuffle.h
new file mode 100644
index 00000000000..292e60d791f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/shuffle.h
@@ -0,0 +1,126 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SHUFFLE_H
+#define _LIBCPP___ALGORITHM_SHUFFLE_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__random/uniform_int_distribution.h>
+#include <__utility/swap.h>
+#include <cstddef>
+#include <cstdint>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_RANDOM_SHUFFLE) \
+  || defined(_LIBCPP_BUILDING_LIBRARY)
+class _LIBCPP_TYPE_VIS __rs_default;
+
+_LIBCPP_FUNC_VIS __rs_default __rs_get();
+
+class _LIBCPP_TYPE_VIS __rs_default
+{
+    static unsigned __c_;
+
+    __rs_default();
+public:
+    typedef uint_fast32_t result_type;
+
+    static const result_type _Min = 0;
+    static const result_type _Max = 0xFFFFFFFF;
+
+    __rs_default(const __rs_default&);
+    ~__rs_default();
+
+    result_type operator()();
+
+    static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
+    static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
+
+    friend _LIBCPP_FUNC_VIS __rs_default __rs_get();
+};
+
+_LIBCPP_FUNC_VIS __rs_default __rs_get();
+
+template <class _RandomAccessIterator>
+_LIBCPP_DEPRECATED_IN_CXX14 void
+random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    typedef uniform_int_distribution<ptrdiff_t> _Dp;
+    typedef typename _Dp::param_type _Pp;
+    difference_type __d = __last - __first;
+    if (__d > 1)
+    {
+        _Dp __uid;
+        __rs_default __g = __rs_get();
+        for (--__last, (void) --__d; __first < __last; ++__first, (void) --__d)
+        {
+            difference_type __i = __uid(__g, _Pp(0, __d));
+            if (__i != difference_type(0))
+                swap(*__first, *(__first + __i));
+        }
+    }
+}
+
+template <class _RandomAccessIterator, class _RandomNumberGenerator>
+_LIBCPP_DEPRECATED_IN_CXX14 void
+random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
+#ifndef _LIBCPP_CXX03_LANG
+               _RandomNumberGenerator&& __rand)
+#else
+               _RandomNumberGenerator& __rand)
+#endif
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    difference_type __d = __last - __first;
+    if (__d > 1)
+    {
+        for (--__last; __first < __last; ++__first, (void) --__d)
+        {
+            difference_type __i = __rand(__d);
+            if (__i != difference_type(0))
+              swap(*__first, *(__first + __i));
+        }
+    }
+}
+#endif
+
+template<class _RandomAccessIterator, class _UniformRandomNumberGenerator>
+    void shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
+                 _UniformRandomNumberGenerator&& __g)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    typedef uniform_int_distribution<ptrdiff_t> _Dp;
+    typedef typename _Dp::param_type _Pp;
+    difference_type __d = __last - __first;
+    if (__d > 1)
+    {
+        _Dp __uid;
+        for (--__last, (void) --__d; __first < __last; ++__first, (void) --__d)
+        {
+            difference_type __i = __uid(__g, _Pp(0, __d));
+            if (__i != difference_type(0))
+                swap(*__first, *(__first + __i));
+        }
+    }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_SHUFFLE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/sift_down.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/sift_down.h
new file mode 100644
index 00000000000..6e801b48b44
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/sift_down.h
@@ -0,0 +1,79 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SIFT_DOWN_H
+#define _LIBCPP___ALGORITHM_SIFT_DOWN_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _RandomAccessIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 void
+__sift_down(_RandomAccessIterator __first, _RandomAccessIterator /*__last*/,
+            _Compare __comp,
+            typename iterator_traits<_RandomAccessIterator>::difference_type __len,
+            _RandomAccessIterator __start)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    // left-child of __start is at 2 * __start + 1
+    // right-child of __start is at 2 * __start + 2
+    difference_type __child = __start - __first;
+
+    if (__len < 2 || (__len - 2) / 2 < __child)
+        return;
+
+    __child = 2 * __child + 1;
+    _RandomAccessIterator __child_i = __first + __child;
+
+    if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + 1))) {
+        // right-child exists and is greater than left-child
+        ++__child_i;
+        ++__child;
+    }
+
+    // check if we are in heap-order
+    if (__comp(*__child_i, *__start))
+        // we are, __start is larger than it's largest child
+        return;
+
+    value_type __top(_VSTD::move(*__start));
+    do
+    {
+        // we are not in heap-order, swap the parent with its largest child
+        *__start = _VSTD::move(*__child_i);
+        __start = __child_i;
+
+        if ((__len - 2) / 2 < __child)
+            break;
+
+        // recompute the child based off of the updated parent
+        __child = 2 * __child + 1;
+        __child_i = __first + __child;
+
+        if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + 1))) {
+            // right-child exists and is greater than left-child
+            ++__child_i;
+            ++__child;
+        }
+
+        // check if we are in heap-order
+    } while (!__comp(*__child_i, __top));
+    *__start = _VSTD::move(__top);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_SIFT_DOWN_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/sort.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/sort.h
new file mode 100644
index 00000000000..0ab6c44a0c5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/sort.h
@@ -0,0 +1,526 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SORT_H
+#define _LIBCPP___ALGORITHM_SORT_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/min_element.h>
+#include <__algorithm/partial_sort.h>
+#include <__algorithm/unwrap_iter.h>
+#include <__utility/swap.h>
+#include <memory>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// stable, 2-3 compares, 0-2 swaps
+
+template <class _Compare, class _ForwardIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 unsigned
+__sort3(_ForwardIterator __x, _ForwardIterator __y, _ForwardIterator __z, _Compare __c)
+{
+    unsigned __r = 0;
+    if (!__c(*__y, *__x))          // if x <= y
+    {
+        if (!__c(*__z, *__y))      // if y <= z
+            return __r;            // x <= y && y <= z
+                                   // x <= y && y > z
+        swap(*__y, *__z);          // x <= z && y < z
+        __r = 1;
+        if (__c(*__y, *__x))       // if x > y
+        {
+            swap(*__x, *__y);      // x < y && y <= z
+            __r = 2;
+        }
+        return __r;                // x <= y && y < z
+    }
+    if (__c(*__z, *__y))           // x > y, if y > z
+    {
+        swap(*__x, *__z);          // x < y && y < z
+        __r = 1;
+        return __r;
+    }
+    swap(*__x, *__y);              // x > y && y <= z
+    __r = 1;                       // x < y && x <= z
+    if (__c(*__z, *__y))           // if y > z
+    {
+        swap(*__y, *__z);          // x <= y && y < z
+        __r = 2;
+    }
+    return __r;
+}                                  // x <= y && y <= z
+
+// stable, 3-6 compares, 0-5 swaps
+
+template <class _Compare, class _ForwardIterator>
+unsigned
+__sort4(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
+            _ForwardIterator __x4, _Compare __c)
+{
+    unsigned __r = _VSTD::__sort3<_Compare>(__x1, __x2, __x3, __c);
+    if (__c(*__x4, *__x3))
+    {
+        swap(*__x3, *__x4);
+        ++__r;
+        if (__c(*__x3, *__x2))
+        {
+            swap(*__x2, *__x3);
+            ++__r;
+            if (__c(*__x2, *__x1))
+            {
+                swap(*__x1, *__x2);
+                ++__r;
+            }
+        }
+    }
+    return __r;
+}
+
+// stable, 4-10 compares, 0-9 swaps
+
+template <class _Compare, class _ForwardIterator>
+_LIBCPP_HIDDEN
+unsigned
+__sort5(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
+            _ForwardIterator __x4, _ForwardIterator __x5, _Compare __c)
+{
+    unsigned __r = _VSTD::__sort4<_Compare>(__x1, __x2, __x3, __x4, __c);
+    if (__c(*__x5, *__x4))
+    {
+        swap(*__x4, *__x5);
+        ++__r;
+        if (__c(*__x4, *__x3))
+        {
+            swap(*__x3, *__x4);
+            ++__r;
+            if (__c(*__x3, *__x2))
+            {
+                swap(*__x2, *__x3);
+                ++__r;
+                if (__c(*__x2, *__x1))
+                {
+                    swap(*__x1, *__x2);
+                    ++__r;
+                }
+            }
+        }
+    }
+    return __r;
+}
+
+// Assumes size > 0
+template <class _Compare, class _BidirectionalIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 void
+__selection_sort(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
+{
+    _BidirectionalIterator __lm1 = __last;
+    for (--__lm1; __first != __lm1; ++__first)
+    {
+        _BidirectionalIterator __i = _VSTD::min_element<_BidirectionalIterator, _Compare&>(__first, __last, __comp);
+        if (__i != __first)
+            swap(*__first, *__i);
+    }
+}
+
+template <class _Compare, class _BidirectionalIterator>
+void
+__insertion_sort(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    if (__first != __last)
+    {
+        _BidirectionalIterator __i = __first;
+        for (++__i; __i != __last; ++__i)
+        {
+            _BidirectionalIterator __j = __i;
+            value_type __t(_VSTD::move(*__j));
+            for (_BidirectionalIterator __k = __i; __k != __first && __comp(__t,  *--__k); --__j)
+                *__j = _VSTD::move(*__k);
+            *__j = _VSTD::move(__t);
+        }
+    }
+}
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__insertion_sort_3(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    _RandomAccessIterator __j = __first+2;
+    _VSTD::__sort3<_Compare>(__first, __first+1, __j, __comp);
+    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
+    {
+        if (__comp(*__i, *__j))
+        {
+            value_type __t(_VSTD::move(*__i));
+            _RandomAccessIterator __k = __j;
+            __j = __i;
+            do
+            {
+                *__j = _VSTD::move(*__k);
+                __j = __k;
+            } while (__j != __first && __comp(__t, *--__k));
+            *__j = _VSTD::move(__t);
+        }
+        __j = __i;
+    }
+}
+
+template <class _Compare, class _RandomAccessIterator>
+bool
+__insertion_sort_incomplete(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    switch (__last - __first)
+    {
+    case 0:
+    case 1:
+        return true;
+    case 2:
+        if (__comp(*--__last, *__first))
+            swap(*__first, *__last);
+        return true;
+    case 3:
+        _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
+        return true;
+    case 4:
+        _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
+        return true;
+    case 5:
+        _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
+        return true;
+    }
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    _RandomAccessIterator __j = __first+2;
+    _VSTD::__sort3<_Compare>(__first, __first+1, __j, __comp);
+    const unsigned __limit = 8;
+    unsigned __count = 0;
+    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
+    {
+        if (__comp(*__i, *__j))
+        {
+            value_type __t(_VSTD::move(*__i));
+            _RandomAccessIterator __k = __j;
+            __j = __i;
+            do
+            {
+                *__j = _VSTD::move(*__k);
+                __j = __k;
+            } while (__j != __first && __comp(__t, *--__k));
+            *__j = _VSTD::move(__t);
+            if (++__count == __limit)
+                return ++__i == __last;
+        }
+        __j = __i;
+    }
+    return true;
+}
+
+template <class _Compare, class _BidirectionalIterator>
+void
+__insertion_sort_move(_BidirectionalIterator __first1, _BidirectionalIterator __last1,
+                      typename iterator_traits<_BidirectionalIterator>::value_type* __first2, _Compare __comp)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    if (__first1 != __last1)
+    {
+        __destruct_n __d(0);
+        unique_ptr<value_type, __destruct_n&> __h(__first2, __d);
+        value_type* __last2 = __first2;
+        ::new ((void*)__last2) value_type(_VSTD::move(*__first1));
+        __d.template __incr<value_type>();
+        for (++__last2; ++__first1 != __last1; ++__last2)
+        {
+            value_type* __j2 = __last2;
+            value_type* __i2 = __j2;
+            if (__comp(*__first1, *--__i2))
+            {
+                ::new ((void*)__j2) value_type(_VSTD::move(*__i2));
+                __d.template __incr<value_type>();
+                for (--__j2; __i2 != __first2 && __comp(*__first1,  *--__i2); --__j2)
+                    *__j2 = _VSTD::move(*__i2);
+                *__j2 = _VSTD::move(*__first1);
+            }
+            else
+            {
+                ::new ((void*)__j2) value_type(_VSTD::move(*__first1));
+                __d.template __incr<value_type>();
+            }
+        }
+        __h.release();
+    }
+}
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    const difference_type __limit = is_trivially_copy_constructible<value_type>::value &&
+                                    is_trivially_copy_assignable<value_type>::value ? 30 : 6;
+    while (true)
+    {
+    __restart:
+        difference_type __len = __last - __first;
+        switch (__len)
+        {
+        case 0:
+        case 1:
+            return;
+        case 2:
+            if (__comp(*--__last, *__first))
+                swap(*__first, *__last);
+            return;
+        case 3:
+            _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
+            return;
+        case 4:
+            _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
+            return;
+        case 5:
+            _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
+            return;
+        }
+        if (__len <= __limit)
+        {
+            _VSTD::__insertion_sort_3<_Compare>(__first, __last, __comp);
+            return;
+        }
+        // __len > 5
+        _RandomAccessIterator __m = __first;
+        _RandomAccessIterator __lm1 = __last;
+        --__lm1;
+        unsigned __n_swaps;
+        {
+        difference_type __delta;
+        if (__len >= 1000)
+        {
+            __delta = __len/2;
+            __m += __delta;
+            __delta /= 2;
+            __n_swaps = _VSTD::__sort5<_Compare>(__first, __first + __delta, __m, __m+__delta, __lm1, __comp);
+        }
+        else
+        {
+            __delta = __len/2;
+            __m += __delta;
+            __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, __lm1, __comp);
+        }
+        }
+        // *__m is median
+        // partition [__first, __m) < *__m and *__m <= [__m, __last)
+        // (this inhibits tossing elements equivalent to __m around unnecessarily)
+        _RandomAccessIterator __i = __first;
+        _RandomAccessIterator __j = __lm1;
+        // j points beyond range to be tested, *__m is known to be <= *__lm1
+        // The search going up is known to be guarded but the search coming down isn't.
+        // Prime the downward search with a guard.
+        if (!__comp(*__i, *__m))  // if *__first == *__m
+        {
+            // *__first == *__m, *__first doesn't go in first part
+            // manually guard downward moving __j against __i
+            while (true)
+            {
+                if (__i == --__j)
+                {
+                    // *__first == *__m, *__m <= all other elements
+                    // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
+                    ++__i;  // __first + 1
+                    __j = __last;
+                    if (!__comp(*__first, *--__j))  // we need a guard if *__first == *(__last-1)
+                    {
+                        while (true)
+                        {
+                            if (__i == __j)
+                                return;  // [__first, __last) all equivalent elements
+                            if (__comp(*__first, *__i))
+                            {
+                                swap(*__i, *__j);
+                                ++__n_swaps;
+                                ++__i;
+                                break;
+                            }
+                            ++__i;
+                        }
+                    }
+                    // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
+                    if (__i == __j)
+                        return;
+                    while (true)
+                    {
+                        while (!__comp(*__first, *__i))
+                            ++__i;
+                        while (__comp(*__first, *--__j))
+                            ;
+                        if (__i >= __j)
+                            break;
+                        swap(*__i, *__j);
+                        ++__n_swaps;
+                        ++__i;
+                    }
+                    // [__first, __i) == *__first and *__first < [__i, __last)
+                    // The first part is sorted, sort the second part
+                    // _VSTD::__sort<_Compare>(__i, __last, __comp);
+                    __first = __i;
+                    goto __restart;
+                }
+                if (__comp(*__j, *__m))
+                {
+                    swap(*__i, *__j);
+                    ++__n_swaps;
+                    break;  // found guard for downward moving __j, now use unguarded partition
+                }
+            }
+        }
+        // It is known that *__i < *__m
+        ++__i;
+        // j points beyond range to be tested, *__m is known to be <= *__lm1
+        // if not yet partitioned...
+        if (__i < __j)
+        {
+            // known that *(__i - 1) < *__m
+            // known that __i <= __m
+            while (true)
+            {
+                // __m still guards upward moving __i
+                while (__comp(*__i, *__m))
+                    ++__i;
+                // It is now known that a guard exists for downward moving __j
+                while (!__comp(*--__j, *__m))
+                    ;
+                if (__i > __j)
+                    break;
+                swap(*__i, *__j);
+                ++__n_swaps;
+                // It is known that __m != __j
+                // If __m just moved, follow it
+                if (__m == __i)
+                    __m = __j;
+                ++__i;
+            }
+        }
+        // [__first, __i) < *__m and *__m <= [__i, __last)
+        if (__i != __m && __comp(*__m, *__i))
+        {
+            swap(*__i, *__m);
+            ++__n_swaps;
+        }
+        // [__first, __i) < *__i and *__i <= [__i+1, __last)
+        // If we were given a perfect partition, see if insertion sort is quick...
+        if (__n_swaps == 0)
+        {
+            bool __fs = _VSTD::__insertion_sort_incomplete<_Compare>(__first, __i, __comp);
+            if (_VSTD::__insertion_sort_incomplete<_Compare>(__i+1, __last, __comp))
+            {
+                if (__fs)
+                    return;
+                __last = __i;
+                continue;
+            }
+            else
+            {
+                if (__fs)
+                {
+                    __first = ++__i;
+                    continue;
+                }
+            }
+        }
+        // sort smaller range with recursive call and larger with tail recursion elimination
+        if (__i - __first < __last - __i)
+        {
+            _VSTD::__sort<_Compare>(__first, __i, __comp);
+            // _VSTD::__sort<_Compare>(__i+1, __last, __comp);
+            __first = ++__i;
+        }
+        else
+        {
+            _VSTD::__sort<_Compare>(__i+1, __last, __comp);
+            // _VSTD::__sort<_Compare>(__first, __i, __comp);
+            __last = __i;
+        }
+    }
+}
+
+template <class _Compare, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+__sort(_Tp** __first, _Tp** __last, __less<_Tp*>&)
+{
+    __less<uintptr_t> __comp;
+    _VSTD::__sort<__less<uintptr_t>&, uintptr_t*>((uintptr_t*)__first, (uintptr_t*)__last, __comp);
+}
+
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<char>&, char*>(char*, char*, __less<char>&))
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
+#endif
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<short>&, short*>(short*, short*, __less<short>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<int>&, int*>(int*, int*, __less<int>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long>&, long*>(long*, long*, __less<long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<float>&, float*>(float*, float*, __less<float>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<double>&, double*>(double*, double*, __less<double>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
+
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<char>&, char*>(char*, char*, __less<char>&))
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
+#endif
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<short>&, short*>(short*, short*, __less<short>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<int>&, int*>(int*, int*, __less<int>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long>&, long*>(long*, long*, __less<long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<float>&, float*>(float*, float*, __less<float>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<double>&, double*>(double*, double*, __less<double>&))
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
+
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS unsigned __sort5<__less<long double>&, long double*>(long double*, long double*, long double*, long double*, long double*, __less<long double>&))
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    if (__libcpp_is_constant_evaluated()) {
+        _VSTD::__partial_sort<_Comp_ref>(__first, __last, __last, _Comp_ref(__comp));
+    } else {
+        _VSTD::__sort<_Comp_ref>(_VSTD::__unwrap_iter(__first), _VSTD::__unwrap_iter(__last), _Comp_ref(__comp));
+    }
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    _VSTD::sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_SORT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/sort_heap.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/sort_heap.h
new file mode 100644
index 00000000000..bf6200c2a08
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/sort_heap.h
@@ -0,0 +1,53 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SORT_HEAP_H
+#define _LIBCPP___ALGORITHM_SORT_HEAP_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/pop_heap.h>
+#include <__iterator/iterator_traits.h>
+#include <type_traits> // swap
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _RandomAccessIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 void
+__sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    for (difference_type __n = __last - __first; __n > 1; --__last, (void) --__n)
+        _VSTD::__pop_heap<_Compare>(__first, __last, __comp, __n);
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    _VSTD::__sort_heap<_Comp_ref>(__first, __last, __comp);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    _VSTD::sort_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_SORT_HEAP_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/stable_partition.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/stable_partition.h
new file mode 100644
index 00000000000..323b323c53d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/stable_partition.h
@@ -0,0 +1,295 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_STABLE_PARTITION_H
+#define _LIBCPP___ALGORITHM_STABLE_PARTITION_H
+
+#include <__config>
+#include <__algorithm/rotate.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/swap.h>
+#include <memory>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Predicate, class _ForwardIterator, class _Distance, class _Pair>
+_ForwardIterator
+__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
+                   _Distance __len, _Pair __p, forward_iterator_tag __fit)
+{
+    // *__first is known to be false
+    // __len >= 1
+    if (__len == 1)
+        return __first;
+    if (__len == 2)
+    {
+        _ForwardIterator __m = __first;
+        if (__pred(*++__m))
+        {
+            swap(*__first, *__m);
+            return __m;
+        }
+        return __first;
+    }
+    if (__len <= __p.second)
+    {   // The buffer is big enough to use
+        typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
+        __destruct_n __d(0);
+        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
+        // Move the falses into the temporary buffer, and the trues to the front of the line
+        // Update __first to always point to the end of the trues
+        value_type* __t = __p.first;
+        ::new ((void*)__t) value_type(_VSTD::move(*__first));
+        __d.template __incr<value_type>();
+        ++__t;
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+        {
+            if (__pred(*__i))
+            {
+                *__first = _VSTD::move(*__i);
+                ++__first;
+            }
+            else
+            {
+                ::new ((void*)__t) value_type(_VSTD::move(*__i));
+                __d.template __incr<value_type>();
+                ++__t;
+            }
+        }
+        // All trues now at start of range, all falses in buffer
+        // Move falses back into range, but don't mess up __first which points to first false
+        __i = __first;
+        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, (void) ++__i)
+            *__i = _VSTD::move(*__t2);
+        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
+        return __first;
+    }
+    // Else not enough buffer, do in place
+    // __len >= 3
+    _ForwardIterator __m = __first;
+    _Distance __len2 = __len / 2;  // __len2 >= 2
+    _VSTD::advance(__m, __len2);
+    // recurse on [__first, __m), *__first know to be false
+    // F?????????????????
+    // f       m         l
+    _ForwardIterator __first_false = _VSTD::__stable_partition<_Predicate&>(__first, __m, __pred, __len2, __p, __fit);
+    // TTTFFFFF??????????
+    // f  ff   m         l
+    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
+    _ForwardIterator __m1 = __m;
+    _ForwardIterator __second_false = __last;
+    _Distance __len_half = __len - __len2;
+    while (__pred(*__m1))
+    {
+        if (++__m1 == __last)
+            goto __second_half_done;
+        --__len_half;
+    }
+    // TTTFFFFFTTTF??????
+    // f  ff   m  m1     l
+    __second_false = _VSTD::__stable_partition<_Predicate&>(__m1, __last, __pred, __len_half, __p, __fit);
+__second_half_done:
+    // TTTFFFFFTTTTTFFFFF
+    // f  ff   m    sf   l
+    return _VSTD::rotate(__first_false, __m, __second_false);
+    // TTTTTTTTFFFFFFFFFF
+    //         |
+}
+
+template <class _Predicate, class _ForwardIterator>
+_ForwardIterator
+__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
+                   forward_iterator_tag)
+{
+    const unsigned __alloc_limit = 3;  // might want to make this a function of trivial assignment
+    // Either prove all true and return __first or point to first false
+    while (true)
+    {
+        if (__first == __last)
+            return __first;
+        if (!__pred(*__first))
+            break;
+        ++__first;
+    }
+    // We now have a reduced range [__first, __last)
+    // *__first is known to be false
+    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
+    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
+    difference_type __len = _VSTD::distance(__first, __last);
+    pair<value_type*, ptrdiff_t> __p(0, 0);
+    unique_ptr<value_type, __return_temporary_buffer> __h;
+    if (__len >= __alloc_limit)
+    {
+        __p = _VSTD::get_temporary_buffer<value_type>(__len);
+        __h.reset(__p.first);
+    }
+    return _VSTD::__stable_partition<_Predicate&>(__first, __last, __pred, __len, __p, forward_iterator_tag());
+}
+
+template <class _Predicate, class _BidirectionalIterator, class _Distance, class _Pair>
+_BidirectionalIterator
+__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
+                   _Distance __len, _Pair __p, bidirectional_iterator_tag __bit)
+{
+    // *__first is known to be false
+    // *__last is known to be true
+    // __len >= 2
+    if (__len == 2)
+    {
+        swap(*__first, *__last);
+        return __last;
+    }
+    if (__len == 3)
+    {
+        _BidirectionalIterator __m = __first;
+        if (__pred(*++__m))
+        {
+            swap(*__first, *__m);
+            swap(*__m, *__last);
+            return __last;
+        }
+        swap(*__m, *__last);
+        swap(*__first, *__m);
+        return __m;
+    }
+    if (__len <= __p.second)
+    {   // The buffer is big enough to use
+        typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+        __destruct_n __d(0);
+        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
+        // Move the falses into the temporary buffer, and the trues to the front of the line
+        // Update __first to always point to the end of the trues
+        value_type* __t = __p.first;
+        ::new ((void*)__t) value_type(_VSTD::move(*__first));
+        __d.template __incr<value_type>();
+        ++__t;
+        _BidirectionalIterator __i = __first;
+        while (++__i != __last)
+        {
+            if (__pred(*__i))
+            {
+                *__first = _VSTD::move(*__i);
+                ++__first;
+            }
+            else
+            {
+                ::new ((void*)__t) value_type(_VSTD::move(*__i));
+                __d.template __incr<value_type>();
+                ++__t;
+            }
+        }
+        // move *__last, known to be true
+        *__first = _VSTD::move(*__i);
+        __i = ++__first;
+        // All trues now at start of range, all falses in buffer
+        // Move falses back into range, but don't mess up __first which points to first false
+        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, (void) ++__i)
+            *__i = _VSTD::move(*__t2);
+        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
+        return __first;
+    }
+    // Else not enough buffer, do in place
+    // __len >= 4
+    _BidirectionalIterator __m = __first;
+    _Distance __len2 = __len / 2;  // __len2 >= 2
+    _VSTD::advance(__m, __len2);
+    // recurse on [__first, __m-1], except reduce __m-1 until *(__m-1) is true, *__first know to be false
+    // F????????????????T
+    // f       m        l
+    _BidirectionalIterator __m1 = __m;
+    _BidirectionalIterator __first_false = __first;
+    _Distance __len_half = __len2;
+    while (!__pred(*--__m1))
+    {
+        if (__m1 == __first)
+            goto __first_half_done;
+        --__len_half;
+    }
+    // F???TFFF?????????T
+    // f   m1  m        l
+    __first_false = _VSTD::__stable_partition<_Predicate&>(__first, __m1, __pred, __len_half, __p, __bit);
+__first_half_done:
+    // TTTFFFFF?????????T
+    // f  ff   m        l
+    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
+    __m1 = __m;
+    _BidirectionalIterator __second_false = __last;
+    ++__second_false;
+    __len_half = __len - __len2;
+    while (__pred(*__m1))
+    {
+        if (++__m1 == __last)
+            goto __second_half_done;
+        --__len_half;
+    }
+    // TTTFFFFFTTTF?????T
+    // f  ff   m  m1    l
+    __second_false = _VSTD::__stable_partition<_Predicate&>(__m1, __last, __pred, __len_half, __p, __bit);
+__second_half_done:
+    // TTTFFFFFTTTTTFFFFF
+    // f  ff   m    sf  l
+    return _VSTD::rotate(__first_false, __m, __second_false);
+    // TTTTTTTTFFFFFFFFFF
+    //         |
+}
+
+template <class _Predicate, class _BidirectionalIterator>
+_BidirectionalIterator
+__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
+                   bidirectional_iterator_tag)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    const difference_type __alloc_limit = 4;  // might want to make this a function of trivial assignment
+    // Either prove all true and return __first or point to first false
+    while (true)
+    {
+        if (__first == __last)
+            return __first;
+        if (!__pred(*__first))
+            break;
+        ++__first;
+    }
+    // __first points to first false, everything prior to __first is already set.
+    // Either prove [__first, __last) is all false and return __first, or point __last to last true
+    do
+    {
+        if (__first == --__last)
+            return __first;
+    } while (!__pred(*__last));
+    // We now have a reduced range [__first, __last]
+    // *__first is known to be false
+    // *__last is known to be true
+    // __len >= 2
+    difference_type __len = _VSTD::distance(__first, __last) + 1;
+    pair<value_type*, ptrdiff_t> __p(0, 0);
+    unique_ptr<value_type, __return_temporary_buffer> __h;
+    if (__len >= __alloc_limit)
+    {
+        __p = _VSTD::get_temporary_buffer<value_type>(__len);
+        __h.reset(__p.first);
+    }
+    return _VSTD::__stable_partition<_Predicate&>(__first, __last, __pred, __len, __p, bidirectional_iterator_tag());
+}
+
+template <class _ForwardIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator
+stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    return _VSTD::__stable_partition<_Predicate&>(__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_STABLE_PARTITION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/stable_sort.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/stable_sort.h
new file mode 100644
index 00000000000..41e17bde99e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/stable_sort.h
@@ -0,0 +1,230 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_STABLE_SORT_H
+#define _LIBCPP___ALGORITHM_STABLE_SORT_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/inplace_merge.h>
+#include <__algorithm/sort.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/swap.h>
+#include <memory>
+#include <type_traits> // swap
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _InputIterator1, class _InputIterator2>
+void
+__merge_move_construct(_InputIterator1 __first1, _InputIterator1 __last1,
+        _InputIterator2 __first2, _InputIterator2 __last2,
+        typename iterator_traits<_InputIterator1>::value_type* __result, _Compare __comp)
+{
+    typedef typename iterator_traits<_InputIterator1>::value_type value_type;
+    __destruct_n __d(0);
+    unique_ptr<value_type, __destruct_n&> __h(__result, __d);
+    for (; true; ++__result)
+    {
+        if (__first1 == __last1)
+        {
+            for (; __first2 != __last2; ++__first2, (void) ++__result, __d.template __incr<value_type>())
+                ::new ((void*)__result) value_type(_VSTD::move(*__first2));
+            __h.release();
+            return;
+        }
+        if (__first2 == __last2)
+        {
+            for (; __first1 != __last1; ++__first1, (void) ++__result, __d.template __incr<value_type>())
+                ::new ((void*)__result) value_type(_VSTD::move(*__first1));
+            __h.release();
+            return;
+        }
+        if (__comp(*__first2, *__first1))
+        {
+            ::new ((void*)__result) value_type(_VSTD::move(*__first2));
+            __d.template __incr<value_type>();
+            ++__first2;
+        }
+        else
+        {
+            ::new ((void*)__result) value_type(_VSTD::move(*__first1));
+            __d.template __incr<value_type>();
+            ++__first1;
+        }
+    }
+}
+
+template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
+void
+__merge_move_assign(_InputIterator1 __first1, _InputIterator1 __last1,
+        _InputIterator2 __first2, _InputIterator2 __last2,
+        _OutputIterator __result, _Compare __comp)
+{
+    for (; __first1 != __last1; ++__result)
+    {
+        if (__first2 == __last2)
+        {
+            for (; __first1 != __last1; ++__first1, (void) ++__result)
+                *__result = _VSTD::move(*__first1);
+            return;
+        }
+        if (__comp(*__first2, *__first1))
+        {
+            *__result = _VSTD::move(*__first2);
+            ++__first2;
+        }
+        else
+        {
+            *__result = _VSTD::move(*__first1);
+            ++__first1;
+        }
+    }
+    for (; __first2 != __last2; ++__first2, (void) ++__result)
+        *__result = _VSTD::move(*__first2);
+}
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
+              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size);
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__stable_sort_move(_RandomAccessIterator __first1, _RandomAccessIterator __last1, _Compare __comp,
+                   typename iterator_traits<_RandomAccessIterator>::difference_type __len,
+                   typename iterator_traits<_RandomAccessIterator>::value_type* __first2)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    switch (__len)
+    {
+    case 0:
+        return;
+    case 1:
+        ::new ((void*)__first2) value_type(_VSTD::move(*__first1));
+        return;
+    case 2:
+        __destruct_n __d(0);
+        unique_ptr<value_type, __destruct_n&> __h2(__first2, __d);
+        if (__comp(*--__last1, *__first1))
+        {
+            ::new ((void*)__first2) value_type(_VSTD::move(*__last1));
+            __d.template __incr<value_type>();
+            ++__first2;
+            ::new ((void*)__first2) value_type(_VSTD::move(*__first1));
+        }
+        else
+        {
+            ::new ((void*)__first2) value_type(_VSTD::move(*__first1));
+            __d.template __incr<value_type>();
+            ++__first2;
+            ::new ((void*)__first2) value_type(_VSTD::move(*__last1));
+        }
+        __h2.release();
+        return;
+    }
+    if (__len <= 8)
+    {
+        _VSTD::__insertion_sort_move<_Compare>(__first1, __last1, __first2, __comp);
+        return;
+    }
+    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
+    _RandomAccessIterator __m = __first1 + __l2;
+    _VSTD::__stable_sort<_Compare>(__first1, __m, __comp, __l2, __first2, __l2);
+    _VSTD::__stable_sort<_Compare>(__m, __last1, __comp, __len - __l2, __first2 + __l2, __len - __l2);
+    _VSTD::__merge_move_construct<_Compare>(__first1, __m, __m, __last1, __first2, __comp);
+}
+
+template <class _Tp>
+struct __stable_sort_switch
+{
+    static const unsigned value = 128*is_trivially_copy_assignable<_Tp>::value;
+};
+
+template <class _Compare, class _RandomAccessIterator>
+void
+__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
+              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
+              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    switch (__len)
+    {
+    case 0:
+    case 1:
+        return;
+    case 2:
+        if (__comp(*--__last, *__first))
+            swap(*__first, *__last);
+        return;
+    }
+    if (__len <= static_cast<difference_type>(__stable_sort_switch<value_type>::value))
+    {
+        _VSTD::__insertion_sort<_Compare>(__first, __last, __comp);
+        return;
+    }
+    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
+    _RandomAccessIterator __m = __first + __l2;
+    if (__len <= __buff_size)
+    {
+        __destruct_n __d(0);
+        unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
+        _VSTD::__stable_sort_move<_Compare>(__first, __m, __comp, __l2, __buff);
+        __d.__set(__l2, (value_type*)nullptr);
+        _VSTD::__stable_sort_move<_Compare>(__m, __last, __comp, __len - __l2, __buff + __l2);
+        __d.__set(__len, (value_type*)nullptr);
+        _VSTD::__merge_move_assign<_Compare>(__buff, __buff + __l2, __buff + __l2, __buff + __len, __first, __comp);
+//         _VSTD::__merge<_Compare>(move_iterator<value_type*>(__buff),
+//                                  move_iterator<value_type*>(__buff + __l2),
+//                                  move_iterator<_RandomAccessIterator>(__buff + __l2),
+//                                  move_iterator<_RandomAccessIterator>(__buff + __len),
+//                                  __first, __comp);
+        return;
+    }
+    _VSTD::__stable_sort<_Compare>(__first, __m, __comp, __l2, __buff, __buff_size);
+    _VSTD::__stable_sort<_Compare>(__m, __last, __comp, __len - __l2, __buff, __buff_size);
+    _VSTD::__inplace_merge<_Compare>(__first, __m, __last, __comp, __l2, __len - __l2, __buff, __buff_size);
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    difference_type __len = __last - __first;
+    pair<value_type*, ptrdiff_t> __buf(0, 0);
+    unique_ptr<value_type, __return_temporary_buffer> __h;
+    if (__len > static_cast<difference_type>(__stable_sort_switch<value_type>::value))
+    {
+        __buf = _VSTD::get_temporary_buffer<value_type>(__len);
+        __h.reset(__buf.first);
+    }
+    typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+    _VSTD::__stable_sort<_Comp_ref>(__first, __last, __comp, __len, __buf.first, __buf.second);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    _VSTD::stable_sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_STABLE_SORT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/swap_ranges.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/swap_ranges.h
new file mode 100644
index 00000000000..2b099c7361f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/swap_ranges.h
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_SWAP_RANGES_H
+#define _LIBCPP___ALGORITHM_SWAP_RANGES_H
+
+#include <__config>
+#include <__utility/swap.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator2
+swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2) {
+  for (; __first1 != __last1; ++__first1, (void)++__first2)
+    swap(*__first1, *__first2);
+  return __first2;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_SWAP_RANGES_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/transform.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/transform.h
new file mode 100644
index 00000000000..494cb7128d2
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/transform.h
@@ -0,0 +1,43 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_TRANSFORM_H
+#define _LIBCPP___ALGORITHM_TRANSFORM_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _OutputIterator, class _UnaryOperation>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+transform(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _UnaryOperation __op)
+{
+    for (; __first != __last; ++__first, (void) ++__result)
+        *__result = __op(*__first);
+    return __result;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _BinaryOperation>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+transform(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2,
+          _OutputIterator __result, _BinaryOperation __binary_op)
+{
+    for (; __first1 != __last1; ++__first1, (void) ++__first2, ++__result)
+        *__result = __binary_op(*__first1, *__first2);
+    return __result;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_TRANSFORM_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/unique.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/unique.h
new file mode 100644
index 00000000000..62f0490b6d6
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/unique.h
@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_UNIQUE_H
+#define _LIBCPP___ALGORITHM_UNIQUE_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/adjacent_find.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// unique
+
+template <class _ForwardIterator, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
+{
+    __first = _VSTD::adjacent_find<_ForwardIterator, _BinaryPredicate&>(__first, __last, __pred);
+    if (__first != __last)
+    {
+        // ...  a  a  ?  ...
+        //      f     i
+        _ForwardIterator __i = __first;
+        for (++__i; ++__i != __last;)
+            if (!__pred(*__first, *__i))
+                *++__first = _VSTD::move(*__i);
+        ++__first;
+    }
+    return __first;
+}
+
+template <class _ForwardIterator>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator
+unique(_ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
+    return _VSTD::unique(__first, __last, __equal_to<__v>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_UNIQUE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/unique_copy.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/unique_copy.h
new file mode 100644
index 00000000000..4c916dc3ada
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/unique_copy.h
@@ -0,0 +1,107 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_UNIQUE_COPY_H
+#define _LIBCPP___ALGORITHM_UNIQUE_COPY_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__iterator/iterator_traits.h>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _BinaryPredicate, class _InputIterator, class _OutputIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator
+__unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
+              input_iterator_tag, output_iterator_tag)
+{
+    if (__first != __last)
+    {
+        typename iterator_traits<_InputIterator>::value_type __t(*__first);
+        *__result = __t;
+        ++__result;
+        while (++__first != __last)
+        {
+            if (!__pred(__t, *__first))
+            {
+                __t = *__first;
+                *__result = __t;
+                ++__result;
+            }
+        }
+    }
+    return __result;
+}
+
+template <class _BinaryPredicate, class _ForwardIterator, class _OutputIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator
+__unique_copy(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
+              forward_iterator_tag, output_iterator_tag)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        *__result = *__i;
+        ++__result;
+        while (++__first != __last)
+        {
+            if (!__pred(*__i, *__first))
+            {
+                *__result = *__first;
+                ++__result;
+                __i = __first;
+            }
+        }
+    }
+    return __result;
+}
+
+template <class _BinaryPredicate, class _InputIterator, class _ForwardIterator>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+__unique_copy(_InputIterator __first, _InputIterator __last, _ForwardIterator __result, _BinaryPredicate __pred,
+              input_iterator_tag, forward_iterator_tag)
+{
+    if (__first != __last)
+    {
+        *__result = *__first;
+        while (++__first != __last)
+            if (!__pred(*__result, *__first))
+                *++__result = *__first;
+        ++__result;
+    }
+    return __result;
+}
+
+template <class _InputIterator, class _OutputIterator, class _BinaryPredicate>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred)
+{
+    return _VSTD::__unique_copy<_BinaryPredicate&>(__first, __last, __result, __pred,
+                               typename iterator_traits<_InputIterator>::iterator_category(),
+                               typename iterator_traits<_OutputIterator>::iterator_category());
+}
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    typedef typename iterator_traits<_InputIterator>::value_type __v;
+    return _VSTD::unique_copy(__first, __last, __result, __equal_to<__v>());
+}
+
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_UNIQUE_COPY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/unwrap_iter.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/unwrap_iter.h
new file mode 100644
index 00000000000..f240cb3c47a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/unwrap_iter.h
@@ -0,0 +1,82 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_UNWRAP_ITER_H
+#define _LIBCPP___ALGORITHM_UNWRAP_ITER_H
+
+#include <__config>
+#include <iterator>
+#include <__memory/pointer_traits.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// The job of __unwrap_iter is to lower contiguous iterators (such as
+// vector<T>::iterator) into pointers, to reduce the number of template
+// instantiations and to enable pointer-based optimizations e.g. in std::copy.
+// For iterators that are not contiguous, it must be a no-op.
+// In debug mode, we don't do this.
+//
+// __unwrap_iter is non-constexpr for user-defined iterators whose
+// `to_address` and/or `operator->` is non-constexpr. This is okay; but we
+// try to avoid doing __unwrap_iter in constant-evaluated contexts anyway.
+//
+// Some algorithms (e.g. std::copy, but not std::sort) need to convert an
+// "unwrapped" result back into a contiguous iterator. Since contiguous iterators
+// are random-access, we can do this portably using iterator arithmetic; this
+// is the job of __rewrap_iter.
+
+template <class _Iter, bool = __is_cpp17_contiguous_iterator<_Iter>::value>
+struct __unwrap_iter_impl {
+    static _LIBCPP_CONSTEXPR _Iter
+    __apply(_Iter __i) _NOEXCEPT {
+        return __i;
+    }
+};
+
+#if _LIBCPP_DEBUG_LEVEL < 2
+
+template <class _Iter>
+struct __unwrap_iter_impl<_Iter, true> {
+    static _LIBCPP_CONSTEXPR decltype(_VSTD::__to_address(declval<_Iter>()))
+    __apply(_Iter __i) _NOEXCEPT {
+        return _VSTD::__to_address(__i);
+    }
+};
+
+#endif // _LIBCPP_DEBUG_LEVEL < 2
+
+template<class _Iter, class _Impl = __unwrap_iter_impl<_Iter> >
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+decltype(_Impl::__apply(declval<_Iter>()))
+__unwrap_iter(_Iter __i) _NOEXCEPT
+{
+    return _Impl::__apply(__i);
+}
+
+template<class _OrigIter>
+_OrigIter __rewrap_iter(_OrigIter, _OrigIter __result)
+{
+    return __result;
+}
+
+template<class _OrigIter, class _UnwrappedIter>
+_OrigIter __rewrap_iter(_OrigIter __first, _UnwrappedIter __result)
+{
+    // Precondition: __result is reachable from __first
+    // Precondition: _OrigIter is a contiguous iterator
+    return __first + (__result - _VSTD::__unwrap_iter(__first));
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_UNWRAP_ITER_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__algorithm/upper_bound.h b/contrib/libs/cxxsupp/libcxx/include/__algorithm/upper_bound.h
new file mode 100644
index 00000000000..4ae7b8f9be1
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__algorithm/upper_bound.h
@@ -0,0 +1,66 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_UPPER_BOUND_H
+#define _LIBCPP___ALGORITHM_UPPER_BOUND_H
+
+#include <__config>
+#include <__algorithm/comp.h>
+#include <__algorithm/half_positive.h>
+#include <iterator>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _ForwardIterator, class _Tp>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
+__upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
+    difference_type __len = _VSTD::distance(__first, __last);
+    while (__len != 0)
+    {
+        difference_type __l2 = _VSTD::__half_positive(__len);
+        _ForwardIterator __m = __first;
+        _VSTD::advance(__m, __l2);
+        if (__comp(__value_, *__m))
+            __len = __l2;
+        else
+        {
+            __first = ++__m;
+            __len -= __l2 + 1;
+        }
+    }
+    return __first;
+}
+
+template <class _ForwardIterator, class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator
+upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
+{
+    return _VSTD::__upper_bound<_Compare&>(__first, __last, __value_, __comp);
+}
+
+template <class _ForwardIterator, class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator
+upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
+{
+    return _VSTD::upper_bound(__first, __last, __value_,
+                             __less<_Tp, typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_UPPER_BOUND_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__availability b/contrib/libs/cxxsupp/libcxx/include/__availability
new file mode 100644
index 00000000000..87d43ed414b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__availability
@@ -0,0 +1,270 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___AVAILABILITY
+#define _LIBCPP___AVAILABILITY
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#   pragma GCC system_header
+#endif
+
+// Libc++ is shipped by various vendors. In particular, it is used as a system
+// library on macOS, iOS and other Apple platforms. In order for users to be
+// able to compile a binary that is intended to be deployed to an older version
+// of a platform, Clang provides availability attributes [1]. These attributes
+// can be placed on declarations and are used to describe the life cycle of a
+// symbol in the library.
+//
+// The main goal is to ensure a compile-time error if a symbol that hasn't been
+// introduced in a previously released library is used in a program that targets
+// that previously released library. Normally, this would be a load-time error
+// when one tries to launch the program against the older library.
+//
+// For example, the filesystem library was introduced in the dylib in macOS 10.15.
+// If a user compiles on a macOS 10.15 host but targets macOS 10.13 with their
+// program, the compiler would normally not complain (because the required
+// declarations are in the headers), but the dynamic loader would fail to find
+// the symbols when actually trying to launch the program on macOS 10.13. To
+// turn this into a compile-time issue instead, declarations are annotated with
+// when they were introduced, and the compiler can produce a diagnostic if the
+// program references something that isn't available on the deployment target.
+//
+// This mechanism is general in nature, and any vendor can add their markup to
+// the library (see below). Whenever a new feature is added that requires support
+// in the shared library, a macro should be added below to mark this feature
+// as unavailable. When vendors decide to ship the feature as part of their
+// shared library, they can update the markup appropriately.
+//
+// Furthermore, many features in the standard library have corresponding
+// feature-test macros. When a feature is made unavailable on some deployment
+// target, a macro should be defined to signal that it is unavailable. That
+// macro can then be picked up when feature-test macros are generated (see
+// generate_feature_test_macro_components.py) to make sure that feature-test
+// macros don't announce a feature as being implemented if it has been marked
+// as unavailable.
+//
+// Note that this mechanism is disabled by default in the "upstream" libc++.
+// Availability annotations are only meaningful when shipping libc++ inside
+// a platform (i.e. as a system library), and so vendors that want them should
+// turn those annotations on at CMake configuration time.
+//
+// [1]: https://clang.llvm.org/docs/AttributeReference.html#availability
+
+
+// For backwards compatibility, allow users to define _LIBCPP_DISABLE_AVAILABILITY
+// for a while.
+#if defined(_LIBCPP_DISABLE_AVAILABILITY)
+#   if !defined(_LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
+#       define _LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS
+#   endif
+#endif
+
+// Availability markup is disabled when building the library, or when the compiler
+// doesn't support the proper attributes.
+#if defined(_LIBCPP_BUILDING_LIBRARY) ||                                        \
+    defined(_LIBCXXABI_BUILDING_LIBRARY) ||                                     \
+    !__has_feature(attribute_availability_with_strict) ||                       \
+    !__has_feature(attribute_availability_in_templates) ||                      \
+    !__has_extension(pragma_clang_attribute_external_declaration)
+#   if !defined(_LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
+#       define _LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS
+#   endif
+#endif
+
+#if defined(_LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS)
+
+    // This controls the availability of std::shared_mutex and std::shared_timed_mutex,
+    // which were added to the dylib later.
+#   define _LIBCPP_AVAILABILITY_SHARED_MUTEX
+// #   define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_shared_mutex
+// #   define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_shared_timed_mutex
+
+    // These macros control the availability of std::bad_optional_access and
+    // other exception types. These were put in the shared library to prevent
+    // code bloat from every user program defining the vtable for these exception
+    // types.
+#   define _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
+#   define _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS
+#   define _LIBCPP_AVAILABILITY_BAD_ANY_CAST
+
+    // This controls the availability of std::uncaught_exceptions().
+#   define _LIBCPP_AVAILABILITY_UNCAUGHT_EXCEPTIONS
+
+    // This controls the availability of the sized version of ::operator delete,
+    // which was added to the dylib later.
+#   define _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE
+
+    // This controls the availability of the std::future_error exception.
+#   define _LIBCPP_AVAILABILITY_FUTURE_ERROR
+
+    // This controls the availability of std::type_info's vtable.
+    // I can't imagine how using std::type_info can work at all if
+    // this isn't supported.
+#   define _LIBCPP_AVAILABILITY_TYPEINFO_VTABLE
+
+    // This controls the availability of std::locale::category members
+    // (e.g. std::locale::collate), which are defined in the dylib.
+#   define _LIBCPP_AVAILABILITY_LOCALE_CATEGORY
+
+    // This controls the availability of atomic operations on std::shared_ptr
+    // (e.g. `std::atomic_store(std::shared_ptr)`), which require a shared
+    // lock table located in the dylib.
+#   define _LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
+
+    // These macros control the availability of all parts of <filesystem> that
+    // depend on something in the dylib.
+#   define _LIBCPP_AVAILABILITY_FILESYSTEM
+#   define _LIBCPP_AVAILABILITY_FILESYSTEM_PUSH
+#   define _LIBCPP_AVAILABILITY_FILESYSTEM_POP
+// #   define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_filesystem
+
+    // This controls the availability of std::to_chars.
+#   define _LIBCPP_AVAILABILITY_TO_CHARS
+
+    // This controls the availability of the C++20 synchronization library,
+    // which requires shared library support for various operations
+    // (see libcxx/src/atomic.cpp).
+#   define _LIBCPP_AVAILABILITY_SYNC
+// #   define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_atomic_wait
+// #   define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_barrier
+// #   define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_latch
+// #   define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_semaphore
+
+    // This controls the availability of the C++20 format library.
+    // The library is in development and not ABI stable yet. P2216 is
+    // retroactively accepted in C++20. This paper contains ABI breaking
+    // changes.
+#   define _LIBCPP_AVAILABILITY_FORMAT
+// #   define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format
+
+#elif defined(__APPLE__)
+
+#   define _LIBCPP_AVAILABILITY_SHARED_MUTEX                                    \
+        __attribute__((availability(macosx,strict,introduced=10.12)))           \
+        __attribute__((availability(ios,strict,introduced=10.0)))               \
+        __attribute__((availability(tvos,strict,introduced=10.0)))              \
+        __attribute__((availability(watchos,strict,introduced=3.0)))
+#   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101200) ||    \
+        (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 100000) || \
+        (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 100000) ||         \
+        (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 30000)
+#       define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_shared_mutex
+#       define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_shared_timed_mutex
+#   endif
+
+#   define _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS                             \
+        __attribute__((availability(macosx,strict,introduced=10.13)))           \
+        __attribute__((availability(ios,strict,introduced=11.0)))               \
+        __attribute__((availability(tvos,strict,introduced=11.0)))              \
+        __attribute__((availability(watchos,strict,introduced=4.0)))
+#   define _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS                              \
+        _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
+#   define _LIBCPP_AVAILABILITY_BAD_ANY_CAST                                    \
+        _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
+
+#   define _LIBCPP_AVAILABILITY_UNCAUGHT_EXCEPTIONS                             \
+        __attribute__((availability(macosx,strict,introduced=10.12)))           \
+        __attribute__((availability(ios,strict,introduced=10.0)))               \
+        __attribute__((availability(tvos,strict,introduced=10.0)))              \
+        __attribute__((availability(watchos,strict,introduced=3.0)))
+
+#   define _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE                                \
+        __attribute__((availability(macosx,strict,introduced=10.12)))           \
+        __attribute__((availability(ios,strict,introduced=10.0)))               \
+        __attribute__((availability(tvos,strict,introduced=10.0)))              \
+        __attribute__((availability(watchos,strict,introduced=3.0)))
+
+#   define _LIBCPP_AVAILABILITY_FUTURE_ERROR                                    \
+        __attribute__((availability(ios,strict,introduced=6.0)))
+
+#   define _LIBCPP_AVAILABILITY_TYPEINFO_VTABLE                                 \
+        __attribute__((availability(macosx,strict,introduced=10.9)))            \
+        __attribute__((availability(ios,strict,introduced=7.0)))
+
+#   define _LIBCPP_AVAILABILITY_LOCALE_CATEGORY                                 \
+        __attribute__((availability(macosx,strict,introduced=10.9)))            \
+        __attribute__((availability(ios,strict,introduced=7.0)))
+
+#   define _LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR                               \
+        __attribute__((availability(macosx,strict,introduced=10.9)))            \
+        __attribute__((availability(ios,strict,introduced=7.0)))
+
+#   define _LIBCPP_AVAILABILITY_FILESYSTEM                                      \
+        __attribute__((availability(macosx,strict,introduced=10.15)))           \
+        __attribute__((availability(ios,strict,introduced=13.0)))               \
+        __attribute__((availability(tvos,strict,introduced=13.0)))              \
+        __attribute__((availability(watchos,strict,introduced=6.0)))
+#   define _LIBCPP_AVAILABILITY_FILESYSTEM_PUSH                                 \
+        _Pragma("clang attribute push(__attribute__((availability(macosx,strict,introduced=10.15))), apply_to=any(function,record))") \
+        _Pragma("clang attribute push(__attribute__((availability(ios,strict,introduced=13.0))), apply_to=any(function,record))")     \
+        _Pragma("clang attribute push(__attribute__((availability(tvos,strict,introduced=13.0))), apply_to=any(function,record))")    \
+        _Pragma("clang attribute push(__attribute__((availability(watchos,strict,introduced=6.0))), apply_to=any(function,record))")
+#   define _LIBCPP_AVAILABILITY_FILESYSTEM_POP                                  \
+        _Pragma("clang attribute pop")                                          \
+        _Pragma("clang attribute pop")                                          \
+        _Pragma("clang attribute pop")                                          \
+        _Pragma("clang attribute pop")
+#   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101500) ||    \
+        (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 130000) || \
+        (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 130000) ||         \
+        (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 60000)
+#       define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_filesystem
+#   endif
+
+#   define _LIBCPP_AVAILABILITY_TO_CHARS                                        \
+        _LIBCPP_AVAILABILITY_FILESYSTEM
+
+#   define _LIBCPP_AVAILABILITY_SYNC                                            \
+        __attribute__((availability(macosx,strict,introduced=11.0)))            \
+        __attribute__((availability(ios,strict,introduced=14.0)))               \
+        __attribute__((availability(tvos,strict,introduced=14.0)))              \
+        __attribute__((availability(watchos,strict,introduced=7.0)))
+#   if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 110000) ||    \
+        (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 140000) || \
+        (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 140000) ||         \
+        (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 70000)
+#       define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_atomic_wait
+#       define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_barrier
+#       define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_latch
+#       define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_semaphore
+#   endif
+
+    // This controls the availability of the C++20 format library.
+    // The library is in development and not ABI stable yet. P2216 is
+    // retroactively accepted in C++20. This paper contains ABI breaking
+    // changes.
+#   define _LIBCPP_AVAILABILITY_FORMAT                                          \
+        __attribute__((unavailable))
+#   define _LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format
+#else
+
+// ...New vendors can add availability markup here...
+
+#   error "It looks like you're trying to enable vendor availability markup, but you haven't defined the corresponding macros yet!"
+
+#endif
+
+// Define availability attributes that depend on _LIBCPP_NO_EXCEPTIONS.
+// Those are defined in terms of the availability attributes above, and
+// should not be vendor-specific.
+#if defined(_LIBCPP_NO_EXCEPTIONS)
+#   define _LIBCPP_AVAILABILITY_FUTURE
+#   define _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
+#   define _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS
+#   define _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
+#else
+#   define _LIBCPP_AVAILABILITY_FUTURE                    _LIBCPP_AVAILABILITY_FUTURE_ERROR
+#   define _LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST        _LIBCPP_AVAILABILITY_BAD_ANY_CAST
+#   define _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
+#   define _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS  _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS
+#endif
+
+#endif // _LIBCPP___AVAILABILITY
diff --git a/contrib/libs/cxxsupp/libcxx/include/__bit/bit_cast.h b/contrib/libs/cxxsupp/libcxx/include/__bit/bit_cast.h
new file mode 100644
index 00000000000..6cfe4d79949
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__bit/bit_cast.h
@@ -0,0 +1,38 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___BIT_BIT_CAST_H
+#define _LIBCPP___BIT_BIT_CAST_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+template<class _ToType, class _FromType, class = enable_if_t<
+  sizeof(_ToType) == sizeof(_FromType) &&
+  is_trivially_copyable_v<_ToType> &&
+  is_trivially_copyable_v<_FromType>
+>>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI
+constexpr _ToType bit_cast(_FromType const& __from) noexcept {
+    return __builtin_bit_cast(_ToType, __from);
+}
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___BIT_BIT_CAST_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__bit_reference b/contrib/libs/cxxsupp/libcxx/include/__bit_reference
new file mode 100644
index 00000000000..489ce886c80
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__bit_reference
@@ -0,0 +1,1303 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___BIT_REFERENCE
+#define _LIBCPP___BIT_REFERENCE
+
+#include <__config>
+#include <__bits>
+#include <algorithm>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Cp, bool _IsConst, class = typename _Cp::__storage_type> class __bit_iterator;
+template <class _Cp> class __bit_const_reference;
+
+template <class _Tp>
+struct __has_storage_type
+{
+    static const bool value = false;
+};
+
+template <class _Cp, bool = __has_storage_type<_Cp>::value>
+class __bit_reference
+{
+    typedef typename _Cp::__storage_type    __storage_type;
+    typedef typename _Cp::__storage_pointer __storage_pointer;
+
+    __storage_pointer __seg_;
+    __storage_type    __mask_;
+
+    friend typename _Cp::__self;
+
+    friend class __bit_const_reference<_Cp>;
+    friend class __bit_iterator<_Cp, false>;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __bit_reference(const __bit_reference&) = default;
+
+    _LIBCPP_INLINE_VISIBILITY operator bool() const _NOEXCEPT
+        {return static_cast<bool>(*__seg_ & __mask_);}
+    _LIBCPP_INLINE_VISIBILITY bool operator ~() const _NOEXCEPT
+        {return !static_cast<bool>(*this);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __bit_reference& operator=(bool __x) _NOEXCEPT
+    {
+        if (__x)
+            *__seg_ |= __mask_;
+        else
+            *__seg_ &= ~__mask_;
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __bit_reference& operator=(const __bit_reference& __x) _NOEXCEPT
+        {return operator=(static_cast<bool>(__x));}
+
+    _LIBCPP_INLINE_VISIBILITY void flip() _NOEXCEPT {*__seg_ ^= __mask_;}
+    _LIBCPP_INLINE_VISIBILITY __bit_iterator<_Cp, false> operator&() const _NOEXCEPT
+        {return __bit_iterator<_Cp, false>(__seg_, static_cast<unsigned>(__libcpp_ctz(__mask_)));}
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    __bit_reference(__storage_pointer __s, __storage_type __m) _NOEXCEPT
+        : __seg_(__s), __mask_(__m) {}
+};
+
+template <class _Cp>
+class __bit_reference<_Cp, false>
+{
+};
+
+template <class _Cp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(__bit_reference<_Cp> __x, __bit_reference<_Cp> __y) _NOEXCEPT
+{
+    bool __t = __x;
+    __x = __y;
+    __y = __t;
+}
+
+template <class _Cp, class _Dp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(__bit_reference<_Cp> __x, __bit_reference<_Dp> __y) _NOEXCEPT
+{
+    bool __t = __x;
+    __x = __y;
+    __y = __t;
+}
+
+template <class _Cp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(__bit_reference<_Cp> __x, bool& __y) _NOEXCEPT
+{
+    bool __t = __x;
+    __x = __y;
+    __y = __t;
+}
+
+template <class _Cp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(bool& __x, __bit_reference<_Cp> __y) _NOEXCEPT
+{
+    bool __t = __x;
+    __x = __y;
+    __y = __t;
+}
+
+template <class _Cp>
+class __bit_const_reference
+{
+    typedef typename _Cp::__storage_type          __storage_type;
+    typedef typename _Cp::__const_storage_pointer __storage_pointer;
+
+    __storage_pointer        __seg_;
+    __storage_type __mask_;
+
+    friend typename _Cp::__self;
+    friend class __bit_iterator<_Cp, true>;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __bit_const_reference(const __bit_const_reference&) = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __bit_const_reference(const __bit_reference<_Cp>& __x) _NOEXCEPT
+        : __seg_(__x.__seg_), __mask_(__x.__mask_) {}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR operator bool() const _NOEXCEPT
+        {return static_cast<bool>(*__seg_ & __mask_);}
+
+    _LIBCPP_INLINE_VISIBILITY __bit_iterator<_Cp, true> operator&() const _NOEXCEPT
+        {return __bit_iterator<_Cp, true>(__seg_, static_cast<unsigned>(__libcpp_ctz(__mask_)));}
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR
+    __bit_const_reference(__storage_pointer __s, __storage_type __m) _NOEXCEPT
+        : __seg_(__s), __mask_(__m) {}
+
+    __bit_const_reference& operator=(const __bit_const_reference&) = delete;
+};
+
+// find
+
+template <class _Cp, bool _IsConst>
+__bit_iterator<_Cp, _IsConst>
+__find_bool_true(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n)
+{
+    typedef __bit_iterator<_Cp, _IsConst> _It;
+    typedef typename _It::__storage_type __storage_type;
+    static const int __bits_per_word = _It::__bits_per_word;
+    // do first partial word
+    if (__first.__ctz_ != 0)
+    {
+        __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
+        __storage_type __dn = _VSTD::min(__clz_f, __n);
+        __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
+        __storage_type __b = *__first.__seg_ & __m;
+        if (__b)
+            return _It(__first.__seg_, static_cast<unsigned>(_VSTD::__libcpp_ctz(__b)));
+        if (__n == __dn)
+            return __first + __n;
+        __n -= __dn;
+        ++__first.__seg_;
+    }
+    // do middle whole words
+    for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word)
+        if (*__first.__seg_)
+            return _It(__first.__seg_, static_cast<unsigned>(_VSTD::__libcpp_ctz(*__first.__seg_)));
+    // do last partial word
+    if (__n > 0)
+    {
+        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+        __storage_type __b = *__first.__seg_ & __m;
+        if (__b)
+            return _It(__first.__seg_, static_cast<unsigned>(_VSTD::__libcpp_ctz(__b)));
+    }
+    return _It(__first.__seg_, static_cast<unsigned>(__n));
+}
+
+template <class _Cp, bool _IsConst>
+__bit_iterator<_Cp, _IsConst>
+__find_bool_false(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n)
+{
+    typedef __bit_iterator<_Cp, _IsConst> _It;
+    typedef typename _It::__storage_type __storage_type;
+    const int __bits_per_word = _It::__bits_per_word;
+    // do first partial word
+    if (__first.__ctz_ != 0)
+    {
+        __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
+        __storage_type __dn = _VSTD::min(__clz_f, __n);
+        __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
+        __storage_type __b = ~*__first.__seg_ & __m;
+        if (__b)
+            return _It(__first.__seg_, static_cast<unsigned>(_VSTD::__libcpp_ctz(__b)));
+        if (__n == __dn)
+            return __first + __n;
+        __n -= __dn;
+        ++__first.__seg_;
+    }
+    // do middle whole words
+    for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word)
+    {
+        __storage_type __b = ~*__first.__seg_;
+        if (__b)
+            return _It(__first.__seg_, static_cast<unsigned>(_VSTD::__libcpp_ctz(__b)));
+    }
+    // do last partial word
+    if (__n > 0)
+    {
+        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+        __storage_type __b = ~*__first.__seg_ & __m;
+        if (__b)
+            return _It(__first.__seg_, static_cast<unsigned>(_VSTD::__libcpp_ctz(__b)));
+    }
+    return _It(__first.__seg_, static_cast<unsigned>(__n));
+}
+
+template <class _Cp, bool _IsConst, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+__bit_iterator<_Cp, _IsConst>
+find(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, const _Tp& __value_)
+{
+    if (static_cast<bool>(__value_))
+        return _VSTD::__find_bool_true(__first, static_cast<typename _Cp::size_type>(__last - __first));
+    return _VSTD::__find_bool_false(__first, static_cast<typename _Cp::size_type>(__last - __first));
+}
+
+// count
+
+template <class _Cp, bool _IsConst>
+typename __bit_iterator<_Cp, _IsConst>::difference_type
+__count_bool_true(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n)
+{
+    typedef __bit_iterator<_Cp, _IsConst> _It;
+    typedef typename _It::__storage_type __storage_type;
+    typedef typename _It::difference_type difference_type;
+    const int __bits_per_word = _It::__bits_per_word;
+    difference_type __r = 0;
+    // do first partial word
+    if (__first.__ctz_ != 0)
+    {
+        __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
+        __storage_type __dn = _VSTD::min(__clz_f, __n);
+        __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
+        __r = _VSTD::__libcpp_popcount(*__first.__seg_ & __m);
+        __n -= __dn;
+        ++__first.__seg_;
+    }
+    // do middle whole words
+    for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word)
+        __r += _VSTD::__libcpp_popcount(*__first.__seg_);
+    // do last partial word
+    if (__n > 0)
+    {
+        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+        __r += _VSTD::__libcpp_popcount(*__first.__seg_ & __m);
+    }
+    return __r;
+}
+
+template <class _Cp, bool _IsConst>
+typename __bit_iterator<_Cp, _IsConst>::difference_type
+__count_bool_false(__bit_iterator<_Cp, _IsConst> __first, typename _Cp::size_type __n)
+{
+    typedef __bit_iterator<_Cp, _IsConst> _It;
+    typedef typename _It::__storage_type __storage_type;
+    typedef typename _It::difference_type difference_type;
+    const int __bits_per_word = _It::__bits_per_word;
+    difference_type __r = 0;
+    // do first partial word
+    if (__first.__ctz_ != 0)
+    {
+        __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
+        __storage_type __dn = _VSTD::min(__clz_f, __n);
+        __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
+        __r = _VSTD::__libcpp_popcount(~*__first.__seg_ & __m);
+        __n -= __dn;
+        ++__first.__seg_;
+    }
+    // do middle whole words
+    for (; __n >= __bits_per_word; ++__first.__seg_, __n -= __bits_per_word)
+        __r += _VSTD::__libcpp_popcount(~*__first.__seg_);
+    // do last partial word
+    if (__n > 0)
+    {
+        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+        __r += _VSTD::__libcpp_popcount(~*__first.__seg_ & __m);
+    }
+    return __r;
+}
+
+template <class _Cp, bool _IsConst, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __bit_iterator<_Cp, _IsConst>::difference_type
+count(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, const _Tp& __value_)
+{
+    if (static_cast<bool>(__value_))
+        return _VSTD::__count_bool_true(__first, static_cast<typename _Cp::size_type>(__last - __first));
+    return _VSTD::__count_bool_false(__first, static_cast<typename _Cp::size_type>(__last - __first));
+}
+
+// fill_n
+
+template <class _Cp>
+void
+__fill_n_false(__bit_iterator<_Cp, false> __first, typename _Cp::size_type __n)
+{
+    typedef __bit_iterator<_Cp, false> _It;
+    typedef typename _It::__storage_type __storage_type;
+    const int __bits_per_word = _It::__bits_per_word;
+    // do first partial word
+    if (__first.__ctz_ != 0)
+    {
+        __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
+        __storage_type __dn = _VSTD::min(__clz_f, __n);
+        __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
+        *__first.__seg_ &= ~__m;
+        __n -= __dn;
+        ++__first.__seg_;
+    }
+    // do middle whole words
+    __storage_type __nw = __n / __bits_per_word;
+    _VSTD::memset(_VSTD::__to_address(__first.__seg_), 0, __nw * sizeof(__storage_type));
+    __n -= __nw * __bits_per_word;
+    // do last partial word
+    if (__n > 0)
+    {
+        __first.__seg_ += __nw;
+        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+        *__first.__seg_ &= ~__m;
+    }
+}
+
+template <class _Cp>
+void
+__fill_n_true(__bit_iterator<_Cp, false> __first, typename _Cp::size_type __n)
+{
+    typedef __bit_iterator<_Cp, false> _It;
+    typedef typename _It::__storage_type __storage_type;
+    const int __bits_per_word = _It::__bits_per_word;
+    // do first partial word
+    if (__first.__ctz_ != 0)
+    {
+        __storage_type __clz_f = static_cast<__storage_type>(__bits_per_word - __first.__ctz_);
+        __storage_type __dn = _VSTD::min(__clz_f, __n);
+        __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
+        *__first.__seg_ |= __m;
+        __n -= __dn;
+        ++__first.__seg_;
+    }
+    // do middle whole words
+    __storage_type __nw = __n / __bits_per_word;
+    _VSTD::memset(_VSTD::__to_address(__first.__seg_), -1, __nw * sizeof(__storage_type));
+    __n -= __nw * __bits_per_word;
+    // do last partial word
+    if (__n > 0)
+    {
+        __first.__seg_ += __nw;
+        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+        *__first.__seg_ |= __m;
+    }
+}
+
+template <class _Cp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+fill_n(__bit_iterator<_Cp, false> __first, typename _Cp::size_type __n, bool __value_)
+{
+    if (__n > 0)
+    {
+        if (__value_)
+            _VSTD::__fill_n_true(__first, __n);
+        else
+            _VSTD::__fill_n_false(__first, __n);
+    }
+}
+
+// fill
+
+template <class _Cp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+fill(__bit_iterator<_Cp, false> __first, __bit_iterator<_Cp, false> __last, bool __value_)
+{
+    _VSTD::fill_n(__first, static_cast<typename _Cp::size_type>(__last - __first), __value_);
+}
+
+// copy
+
+template <class _Cp, bool _IsConst>
+__bit_iterator<_Cp, false>
+__copy_aligned(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last,
+                                                     __bit_iterator<_Cp, false> __result)
+{
+    typedef __bit_iterator<_Cp, _IsConst> _In;
+    typedef  typename _In::difference_type difference_type;
+    typedef typename _In::__storage_type __storage_type;
+    const int __bits_per_word = _In::__bits_per_word;
+    difference_type __n = __last - __first;
+    if (__n > 0)
+    {
+        // do first word
+        if (__first.__ctz_ != 0)
+        {
+            unsigned __clz = __bits_per_word - __first.__ctz_;
+            difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz), __n);
+            __n -= __dn;
+            __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz - __dn));
+            __storage_type __b = *__first.__seg_ & __m;
+            *__result.__seg_ &= ~__m;
+            *__result.__seg_ |= __b;
+            __result.__seg_ += (__dn + __result.__ctz_) / __bits_per_word;
+            __result.__ctz_ = static_cast<unsigned>((__dn + __result.__ctz_)  % __bits_per_word);
+            ++__first.__seg_;
+            // __first.__ctz_ = 0;
+        }
+        // __first.__ctz_ == 0;
+        // do middle words
+        __storage_type __nw = __n / __bits_per_word;
+        _VSTD::memmove(_VSTD::__to_address(__result.__seg_),
+                       _VSTD::__to_address(__first.__seg_),
+                       __nw * sizeof(__storage_type));
+        __n -= __nw * __bits_per_word;
+        __result.__seg_ += __nw;
+        // do last word
+        if (__n > 0)
+        {
+            __first.__seg_ += __nw;
+            __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+            __storage_type __b = *__first.__seg_ & __m;
+            *__result.__seg_ &= ~__m;
+            *__result.__seg_ |= __b;
+            __result.__ctz_ = static_cast<unsigned>(__n);
+        }
+    }
+    return __result;
+}
+
+template <class _Cp, bool _IsConst>
+__bit_iterator<_Cp, false>
+__copy_unaligned(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last,
+                                                       __bit_iterator<_Cp, false> __result)
+{
+    typedef __bit_iterator<_Cp, _IsConst> _In;
+    typedef  typename _In::difference_type difference_type;
+    typedef typename _In::__storage_type __storage_type;
+    static const int __bits_per_word = _In::__bits_per_word;
+    difference_type __n = __last - __first;
+    if (__n > 0)
+    {
+        // do first word
+        if (__first.__ctz_ != 0)
+        {
+            unsigned __clz_f = __bits_per_word - __first.__ctz_;
+            difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz_f), __n);
+            __n -= __dn;
+            __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
+            __storage_type __b = *__first.__seg_ & __m;
+            unsigned __clz_r = __bits_per_word - __result.__ctz_;
+            __storage_type __ddn = _VSTD::min<__storage_type>(__dn, __clz_r);
+            __m = (~__storage_type(0) << __result.__ctz_) & (~__storage_type(0) >> (__clz_r - __ddn));
+            *__result.__seg_ &= ~__m;
+            if (__result.__ctz_ > __first.__ctz_)
+                *__result.__seg_ |= __b << (__result.__ctz_ - __first.__ctz_);
+            else
+                *__result.__seg_ |= __b >> (__first.__ctz_ - __result.__ctz_);
+            __result.__seg_ += (__ddn + __result.__ctz_) / __bits_per_word;
+            __result.__ctz_ = static_cast<unsigned>((__ddn + __result.__ctz_)  % __bits_per_word);
+            __dn -= __ddn;
+            if (__dn > 0)
+            {
+                __m = ~__storage_type(0) >> (__bits_per_word - __dn);
+                *__result.__seg_ &= ~__m;
+                *__result.__seg_ |= __b >> (__first.__ctz_ + __ddn);
+                __result.__ctz_ = static_cast<unsigned>(__dn);
+            }
+            ++__first.__seg_;
+            // __first.__ctz_ = 0;
+        }
+        // __first.__ctz_ == 0;
+        // do middle words
+        unsigned __clz_r = __bits_per_word - __result.__ctz_;
+        __storage_type __m = ~__storage_type(0) << __result.__ctz_;
+        for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first.__seg_)
+        {
+            __storage_type __b = *__first.__seg_;
+            *__result.__seg_ &= ~__m;
+            *__result.__seg_ |= __b << __result.__ctz_;
+            ++__result.__seg_;
+            *__result.__seg_ &= __m;
+            *__result.__seg_ |= __b >> __clz_r;
+        }
+        // do last word
+        if (__n > 0)
+        {
+            __m = ~__storage_type(0) >> (__bits_per_word - __n);
+            __storage_type __b = *__first.__seg_ & __m;
+            __storage_type __dn = _VSTD::min(__n, static_cast<difference_type>(__clz_r));
+            __m = (~__storage_type(0) << __result.__ctz_) & (~__storage_type(0) >> (__clz_r - __dn));
+            *__result.__seg_ &= ~__m;
+            *__result.__seg_ |= __b << __result.__ctz_;
+            __result.__seg_ += (__dn + __result.__ctz_) / __bits_per_word;
+            __result.__ctz_ = static_cast<unsigned>((__dn + __result.__ctz_)  % __bits_per_word);
+            __n -= __dn;
+            if (__n > 0)
+            {
+                __m = ~__storage_type(0) >> (__bits_per_word - __n);
+                *__result.__seg_ &= ~__m;
+                *__result.__seg_ |= __b >> __dn;
+                __result.__ctz_ = static_cast<unsigned>(__n);
+            }
+        }
+    }
+    return __result;
+}
+
+template <class _Cp, bool _IsConst>
+inline _LIBCPP_INLINE_VISIBILITY
+__bit_iterator<_Cp, false>
+copy(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, __bit_iterator<_Cp, false> __result)
+{
+    if (__first.__ctz_ == __result.__ctz_)
+        return _VSTD::__copy_aligned(__first, __last, __result);
+    return _VSTD::__copy_unaligned(__first, __last, __result);
+}
+
+// copy_backward
+
+template <class _Cp, bool _IsConst>
+__bit_iterator<_Cp, false>
+__copy_backward_aligned(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last,
+                                                     __bit_iterator<_Cp, false> __result)
+{
+    typedef __bit_iterator<_Cp, _IsConst> _In;
+    typedef  typename _In::difference_type difference_type;
+    typedef typename _In::__storage_type __storage_type;
+    const int __bits_per_word = _In::__bits_per_word;
+    difference_type __n = __last - __first;
+    if (__n > 0)
+    {
+        // do first word
+        if (__last.__ctz_ != 0)
+        {
+            difference_type __dn = _VSTD::min(static_cast<difference_type>(__last.__ctz_), __n);
+            __n -= __dn;
+            unsigned __clz = __bits_per_word - __last.__ctz_;
+            __storage_type __m = (~__storage_type(0) << (__last.__ctz_ - __dn)) & (~__storage_type(0) >> __clz);
+            __storage_type __b = *__last.__seg_ & __m;
+            *__result.__seg_ &= ~__m;
+            *__result.__seg_ |= __b;
+            __result.__ctz_ = static_cast<unsigned>(((-__dn & (__bits_per_word - 1)) +
+                                                       __result.__ctz_)  % __bits_per_word);
+            // __last.__ctz_ = 0
+         }
+        // __last.__ctz_ == 0 || __n == 0
+        // __result.__ctz_ == 0 || __n == 0
+        // do middle words
+        __storage_type __nw = __n / __bits_per_word;
+        __result.__seg_ -= __nw;
+        __last.__seg_ -= __nw;
+        _VSTD::memmove(_VSTD::__to_address(__result.__seg_),
+                       _VSTD::__to_address(__last.__seg_),
+                       __nw * sizeof(__storage_type));
+        __n -= __nw * __bits_per_word;
+        // do last word
+        if (__n > 0)
+        {
+            __storage_type __m = ~__storage_type(0) << (__bits_per_word - __n);
+            __storage_type __b = *--__last.__seg_ & __m;
+            *--__result.__seg_ &= ~__m;
+            *__result.__seg_ |= __b;
+            __result.__ctz_ = static_cast<unsigned>(-__n & (__bits_per_word - 1));
+        }
+    }
+    return __result;
+}
+
+template <class _Cp, bool _IsConst>
+__bit_iterator<_Cp, false>
+__copy_backward_unaligned(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last,
+                                                       __bit_iterator<_Cp, false> __result)
+{
+    typedef __bit_iterator<_Cp, _IsConst> _In;
+    typedef  typename _In::difference_type difference_type;
+    typedef typename _In::__storage_type __storage_type;
+    const int __bits_per_word = _In::__bits_per_word;
+    difference_type __n = __last - __first;
+    if (__n > 0)
+    {
+        // do first word
+        if (__last.__ctz_ != 0)
+        {
+            difference_type __dn = _VSTD::min(static_cast<difference_type>(__last.__ctz_), __n);
+            __n -= __dn;
+            unsigned __clz_l = __bits_per_word - __last.__ctz_;
+            __storage_type __m = (~__storage_type(0) << (__last.__ctz_ - __dn)) & (~__storage_type(0) >> __clz_l);
+            __storage_type __b = *__last.__seg_ & __m;
+            unsigned __clz_r = __bits_per_word - __result.__ctz_;
+            __storage_type __ddn = _VSTD::min(__dn, static_cast<difference_type>(__result.__ctz_));
+            if (__ddn > 0)
+            {
+                __m = (~__storage_type(0) << (__result.__ctz_ - __ddn)) & (~__storage_type(0) >> __clz_r);
+                *__result.__seg_ &= ~__m;
+                if (__result.__ctz_ > __last.__ctz_)
+                    *__result.__seg_ |= __b << (__result.__ctz_ - __last.__ctz_);
+                else
+                    *__result.__seg_ |= __b >> (__last.__ctz_ - __result.__ctz_);
+                __result.__ctz_ = static_cast<unsigned>(((-__ddn & (__bits_per_word - 1)) +
+                                                         __result.__ctz_)  % __bits_per_word);
+                __dn -= __ddn;
+            }
+            if (__dn > 0)
+            {
+                // __result.__ctz_ == 0
+                --__result.__seg_;
+                __result.__ctz_ = static_cast<unsigned>(-__dn & (__bits_per_word - 1));
+                __m = ~__storage_type(0) << __result.__ctz_;
+                *__result.__seg_ &= ~__m;
+                __last.__ctz_ -= __dn + __ddn;
+                *__result.__seg_ |= __b << (__result.__ctz_ - __last.__ctz_);
+            }
+            // __last.__ctz_ = 0
+         }
+        // __last.__ctz_ == 0 || __n == 0
+        // __result.__ctz_ != 0 || __n == 0
+        // do middle words
+        unsigned __clz_r = __bits_per_word - __result.__ctz_;
+        __storage_type __m = ~__storage_type(0) >> __clz_r;
+        for (; __n >= __bits_per_word; __n -= __bits_per_word)
+        {
+            __storage_type __b = *--__last.__seg_;
+            *__result.__seg_ &= ~__m;
+            *__result.__seg_ |= __b >> __clz_r;
+            *--__result.__seg_ &= __m;
+            *__result.__seg_ |= __b << __result.__ctz_;
+        }
+        // do last word
+        if (__n > 0)
+        {
+            __m = ~__storage_type(0) << (__bits_per_word - __n);
+            __storage_type __b = *--__last.__seg_ & __m;
+            __clz_r = __bits_per_word - __result.__ctz_;
+            __storage_type __dn = _VSTD::min(__n, static_cast<difference_type>(__result.__ctz_));
+            __m = (~__storage_type(0) << (__result.__ctz_ - __dn)) & (~__storage_type(0) >> __clz_r);
+            *__result.__seg_ &= ~__m;
+            *__result.__seg_ |= __b >> (__bits_per_word - __result.__ctz_);
+            __result.__ctz_ = static_cast<unsigned>(((-__dn & (__bits_per_word - 1)) +
+                                                     __result.__ctz_)  % __bits_per_word);
+            __n -= __dn;
+            if (__n > 0)
+            {
+                // __result.__ctz_ == 0
+                --__result.__seg_;
+                __result.__ctz_ = static_cast<unsigned>(-__n & (__bits_per_word - 1));
+                __m = ~__storage_type(0) << __result.__ctz_;
+                *__result.__seg_ &= ~__m;
+                *__result.__seg_ |= __b << (__result.__ctz_ - (__bits_per_word - __n - __dn));
+            }
+        }
+    }
+    return __result;
+}
+
+template <class _Cp, bool _IsConst>
+inline _LIBCPP_INLINE_VISIBILITY
+__bit_iterator<_Cp, false>
+copy_backward(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, __bit_iterator<_Cp, false> __result)
+{
+    if (__last.__ctz_ == __result.__ctz_)
+        return _VSTD::__copy_backward_aligned(__first, __last, __result);
+    return _VSTD::__copy_backward_unaligned(__first, __last, __result);
+}
+
+// move
+
+template <class _Cp, bool _IsConst>
+inline _LIBCPP_INLINE_VISIBILITY
+__bit_iterator<_Cp, false>
+move(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, __bit_iterator<_Cp, false> __result)
+{
+    return _VSTD::copy(__first, __last, __result);
+}
+
+// move_backward
+
+template <class _Cp, bool _IsConst>
+inline _LIBCPP_INLINE_VISIBILITY
+__bit_iterator<_Cp, false>
+move_backward(__bit_iterator<_Cp, _IsConst> __first, __bit_iterator<_Cp, _IsConst> __last, __bit_iterator<_Cp, false> __result)
+{
+    return _VSTD::copy_backward(__first, __last, __result);
+}
+
+// swap_ranges
+
+template <class __C1, class __C2>
+__bit_iterator<__C2, false>
+__swap_ranges_aligned(__bit_iterator<__C1, false> __first, __bit_iterator<__C1, false> __last,
+                      __bit_iterator<__C2, false> __result)
+{
+    typedef __bit_iterator<__C1, false> _I1;
+    typedef  typename _I1::difference_type difference_type;
+    typedef typename _I1::__storage_type __storage_type;
+    const int __bits_per_word = _I1::__bits_per_word;
+    difference_type __n = __last - __first;
+    if (__n > 0)
+    {
+        // do first word
+        if (__first.__ctz_ != 0)
+        {
+            unsigned __clz = __bits_per_word - __first.__ctz_;
+            difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz), __n);
+            __n -= __dn;
+            __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz - __dn));
+            __storage_type __b1 = *__first.__seg_ & __m;
+            *__first.__seg_ &= ~__m;
+            __storage_type __b2 = *__result.__seg_ & __m;
+            *__result.__seg_ &= ~__m;
+            *__result.__seg_ |= __b1;
+            *__first.__seg_  |= __b2;
+            __result.__seg_ += (__dn + __result.__ctz_) / __bits_per_word;
+            __result.__ctz_ = static_cast<unsigned>((__dn + __result.__ctz_)  % __bits_per_word);
+            ++__first.__seg_;
+            // __first.__ctz_ = 0;
+        }
+        // __first.__ctz_ == 0;
+        // do middle words
+        for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first.__seg_, ++__result.__seg_)
+            swap(*__first.__seg_, *__result.__seg_);
+        // do last word
+        if (__n > 0)
+        {
+            __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+            __storage_type __b1 = *__first.__seg_ & __m;
+            *__first.__seg_ &= ~__m;
+            __storage_type __b2 = *__result.__seg_ & __m;
+            *__result.__seg_ &= ~__m;
+            *__result.__seg_ |= __b1;
+            *__first.__seg_  |= __b2;
+            __result.__ctz_ = static_cast<unsigned>(__n);
+        }
+    }
+    return __result;
+}
+
+template <class __C1, class __C2>
+__bit_iterator<__C2, false>
+__swap_ranges_unaligned(__bit_iterator<__C1, false> __first, __bit_iterator<__C1, false> __last,
+                        __bit_iterator<__C2, false> __result)
+{
+    typedef __bit_iterator<__C1, false> _I1;
+    typedef  typename _I1::difference_type difference_type;
+    typedef typename _I1::__storage_type __storage_type;
+    const int __bits_per_word = _I1::__bits_per_word;
+    difference_type __n = __last - __first;
+    if (__n > 0)
+    {
+        // do first word
+        if (__first.__ctz_ != 0)
+        {
+            unsigned __clz_f = __bits_per_word - __first.__ctz_;
+            difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz_f), __n);
+            __n -= __dn;
+            __storage_type __m = (~__storage_type(0) << __first.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
+            __storage_type __b1 = *__first.__seg_ & __m;
+            *__first.__seg_ &= ~__m;
+            unsigned __clz_r = __bits_per_word - __result.__ctz_;
+            __storage_type __ddn = _VSTD::min<__storage_type>(__dn, __clz_r);
+            __m = (~__storage_type(0) << __result.__ctz_) & (~__storage_type(0) >> (__clz_r - __ddn));
+            __storage_type __b2 = *__result.__seg_ & __m;
+            *__result.__seg_ &= ~__m;
+            if (__result.__ctz_ > __first.__ctz_)
+            {
+                unsigned __s = __result.__ctz_ - __first.__ctz_;
+                *__result.__seg_ |= __b1 << __s;
+                *__first.__seg_  |= __b2 >> __s;
+            }
+            else
+            {
+                unsigned __s = __first.__ctz_ - __result.__ctz_;
+                *__result.__seg_ |= __b1 >> __s;
+                *__first.__seg_  |= __b2 << __s;
+            }
+            __result.__seg_ += (__ddn + __result.__ctz_) / __bits_per_word;
+            __result.__ctz_ = static_cast<unsigned>((__ddn + __result.__ctz_)  % __bits_per_word);
+            __dn -= __ddn;
+            if (__dn > 0)
+            {
+                __m = ~__storage_type(0) >> (__bits_per_word - __dn);
+                __b2 = *__result.__seg_ & __m;
+                *__result.__seg_ &= ~__m;
+                unsigned __s = __first.__ctz_ + __ddn;
+                *__result.__seg_ |= __b1 >> __s;
+                *__first.__seg_  |= __b2 << __s;
+                __result.__ctz_ = static_cast<unsigned>(__dn);
+            }
+            ++__first.__seg_;
+            // __first.__ctz_ = 0;
+        }
+        // __first.__ctz_ == 0;
+        // do middle words
+        __storage_type __m = ~__storage_type(0) << __result.__ctz_;
+        unsigned __clz_r = __bits_per_word - __result.__ctz_;
+        for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first.__seg_)
+        {
+            __storage_type __b1 = *__first.__seg_;
+            __storage_type __b2 = *__result.__seg_ & __m;
+            *__result.__seg_ &= ~__m;
+            *__result.__seg_ |= __b1 << __result.__ctz_;
+            *__first.__seg_  = __b2 >> __result.__ctz_;
+            ++__result.__seg_;
+            __b2 = *__result.__seg_ & ~__m;
+            *__result.__seg_ &= __m;
+            *__result.__seg_ |= __b1 >> __clz_r;
+            *__first.__seg_  |= __b2 << __clz_r;
+        }
+        // do last word
+        if (__n > 0)
+        {
+            __m = ~__storage_type(0) >> (__bits_per_word - __n);
+            __storage_type __b1 = *__first.__seg_ & __m;
+            *__first.__seg_ &= ~__m;
+            __storage_type __dn = _VSTD::min<__storage_type>(__n, __clz_r);
+            __m = (~__storage_type(0) << __result.__ctz_) & (~__storage_type(0) >> (__clz_r - __dn));
+            __storage_type __b2 = *__result.__seg_ & __m;
+            *__result.__seg_ &= ~__m;
+            *__result.__seg_ |= __b1 << __result.__ctz_;
+            *__first.__seg_  |= __b2 >> __result.__ctz_;
+            __result.__seg_ += (__dn + __result.__ctz_) / __bits_per_word;
+            __result.__ctz_ = static_cast<unsigned>((__dn + __result.__ctz_)  % __bits_per_word);
+            __n -= __dn;
+            if (__n > 0)
+            {
+                __m = ~__storage_type(0) >> (__bits_per_word - __n);
+                __b2 = *__result.__seg_ & __m;
+                *__result.__seg_ &= ~__m;
+                *__result.__seg_ |= __b1 >> __dn;
+                *__first.__seg_  |= __b2 << __dn;
+                __result.__ctz_ = static_cast<unsigned>(__n);
+            }
+        }
+    }
+    return __result;
+}
+
+template <class __C1, class __C2>
+inline _LIBCPP_INLINE_VISIBILITY
+__bit_iterator<__C2, false>
+swap_ranges(__bit_iterator<__C1, false> __first1, __bit_iterator<__C1, false> __last1,
+            __bit_iterator<__C2, false> __first2)
+{
+    if (__first1.__ctz_ == __first2.__ctz_)
+        return _VSTD::__swap_ranges_aligned(__first1, __last1, __first2);
+    return _VSTD::__swap_ranges_unaligned(__first1, __last1, __first2);
+}
+
+// rotate
+
+template <class _Cp>
+struct __bit_array
+{
+    typedef typename _Cp::difference_type difference_type;
+    typedef typename _Cp::__storage_type  __storage_type;
+    typedef typename _Cp::__storage_pointer __storage_pointer;
+    typedef typename _Cp::iterator        iterator;
+    static const unsigned __bits_per_word = _Cp::__bits_per_word;
+    static const unsigned _Np = 4;
+
+    difference_type __size_;
+    __storage_type __word_[_Np];
+
+    _LIBCPP_INLINE_VISIBILITY static difference_type capacity()
+        {return static_cast<difference_type>(_Np * __bits_per_word);}
+    _LIBCPP_INLINE_VISIBILITY explicit __bit_array(difference_type __s) : __size_(__s) {}
+    _LIBCPP_INLINE_VISIBILITY iterator begin()
+    {
+        return iterator(pointer_traits<__storage_pointer>::pointer_to(__word_[0]), 0);
+    }
+    _LIBCPP_INLINE_VISIBILITY iterator end()
+    {
+        return iterator(pointer_traits<__storage_pointer>::pointer_to(__word_[0]) + __size_ / __bits_per_word,
+                                                  static_cast<unsigned>(__size_ % __bits_per_word));
+    }
+};
+
+template <class _Cp>
+__bit_iterator<_Cp, false>
+rotate(__bit_iterator<_Cp, false> __first, __bit_iterator<_Cp, false> __middle, __bit_iterator<_Cp, false> __last)
+{
+    typedef __bit_iterator<_Cp, false> _I1;
+    typedef  typename _I1::difference_type difference_type;
+    difference_type __d1 = __middle - __first;
+    difference_type __d2 = __last - __middle;
+    _I1 __r = __first + __d2;
+    while (__d1 != 0 && __d2 != 0)
+    {
+        if (__d1 <= __d2)
+        {
+            if (__d1 <= __bit_array<_Cp>::capacity())
+            {
+                __bit_array<_Cp> __b(__d1);
+                _VSTD::copy(__first, __middle, __b.begin());
+                _VSTD::copy(__b.begin(), __b.end(), _VSTD::copy(__middle, __last, __first));
+                break;
+            }
+            else
+            {
+                __bit_iterator<_Cp, false> __mp = _VSTD::swap_ranges(__first, __middle, __middle);
+                __first = __middle;
+                __middle = __mp;
+                __d2 -= __d1;
+            }
+        }
+        else
+        {
+            if (__d2 <= __bit_array<_Cp>::capacity())
+            {
+                __bit_array<_Cp> __b(__d2);
+                _VSTD::copy(__middle, __last, __b.begin());
+                _VSTD::copy_backward(__b.begin(), __b.end(), _VSTD::copy_backward(__first, __middle, __last));
+                break;
+            }
+            else
+            {
+                __bit_iterator<_Cp, false> __mp = __first + __d2;
+                _VSTD::swap_ranges(__first, __mp, __middle);
+                __first = __mp;
+                __d1 -= __d2;
+            }
+        }
+    }
+    return __r;
+}
+
+// equal
+
+template <class _Cp, bool _IC1, bool _IC2>
+bool
+__equal_unaligned(__bit_iterator<_Cp, _IC1> __first1, __bit_iterator<_Cp, _IC1> __last1,
+                  __bit_iterator<_Cp, _IC2> __first2)
+{
+    typedef __bit_iterator<_Cp, _IC1> _It;
+    typedef  typename _It::difference_type difference_type;
+    typedef typename _It::__storage_type __storage_type;
+    static const int __bits_per_word = _It::__bits_per_word;
+    difference_type __n = __last1 - __first1;
+    if (__n > 0)
+    {
+        // do first word
+        if (__first1.__ctz_ != 0)
+        {
+            unsigned __clz_f = __bits_per_word - __first1.__ctz_;
+            difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz_f), __n);
+            __n -= __dn;
+            __storage_type __m = (~__storage_type(0) << __first1.__ctz_) & (~__storage_type(0) >> (__clz_f - __dn));
+            __storage_type __b = *__first1.__seg_ & __m;
+            unsigned __clz_r = __bits_per_word - __first2.__ctz_;
+            __storage_type __ddn = _VSTD::min<__storage_type>(__dn, __clz_r);
+            __m = (~__storage_type(0) << __first2.__ctz_) & (~__storage_type(0) >> (__clz_r - __ddn));
+            if (__first2.__ctz_ > __first1.__ctz_)
+            {
+                if ((*__first2.__seg_ & __m) != (__b << (__first2.__ctz_ - __first1.__ctz_)))
+                    return false;
+            }
+            else
+            {
+                if ((*__first2.__seg_ & __m) != (__b >> (__first1.__ctz_ - __first2.__ctz_)))
+                    return false;
+            }
+            __first2.__seg_ += (__ddn + __first2.__ctz_) / __bits_per_word;
+            __first2.__ctz_ = static_cast<unsigned>((__ddn + __first2.__ctz_)  % __bits_per_word);
+            __dn -= __ddn;
+            if (__dn > 0)
+            {
+                __m = ~__storage_type(0) >> (__bits_per_word - __dn);
+                if ((*__first2.__seg_ & __m) != (__b >> (__first1.__ctz_ + __ddn)))
+                    return false;
+                __first2.__ctz_ = static_cast<unsigned>(__dn);
+            }
+            ++__first1.__seg_;
+            // __first1.__ctz_ = 0;
+        }
+        // __first1.__ctz_ == 0;
+        // do middle words
+        unsigned __clz_r = __bits_per_word - __first2.__ctz_;
+        __storage_type __m = ~__storage_type(0) << __first2.__ctz_;
+        for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first1.__seg_)
+        {
+            __storage_type __b = *__first1.__seg_;
+            if ((*__first2.__seg_ & __m) != (__b << __first2.__ctz_))
+                return false;
+            ++__first2.__seg_;
+            if ((*__first2.__seg_ & ~__m) != (__b >> __clz_r))
+                return false;
+        }
+        // do last word
+        if (__n > 0)
+        {
+            __m = ~__storage_type(0) >> (__bits_per_word - __n);
+            __storage_type __b = *__first1.__seg_ & __m;
+            __storage_type __dn = _VSTD::min(__n, static_cast<difference_type>(__clz_r));
+            __m = (~__storage_type(0) << __first2.__ctz_) & (~__storage_type(0) >> (__clz_r - __dn));
+            if ((*__first2.__seg_ & __m) != (__b << __first2.__ctz_))
+                return false;
+            __first2.__seg_ += (__dn + __first2.__ctz_) / __bits_per_word;
+            __first2.__ctz_ = static_cast<unsigned>((__dn + __first2.__ctz_)  % __bits_per_word);
+            __n -= __dn;
+            if (__n > 0)
+            {
+                __m = ~__storage_type(0) >> (__bits_per_word - __n);
+                if ((*__first2.__seg_ & __m) != (__b >> __dn))
+                    return false;
+            }
+        }
+    }
+    return true;
+}
+
+template <class _Cp, bool _IC1, bool _IC2>
+bool
+__equal_aligned(__bit_iterator<_Cp, _IC1> __first1, __bit_iterator<_Cp, _IC1> __last1,
+                __bit_iterator<_Cp, _IC2> __first2)
+{
+    typedef __bit_iterator<_Cp, _IC1> _It;
+    typedef  typename _It::difference_type difference_type;
+    typedef typename _It::__storage_type __storage_type;
+    static const int __bits_per_word = _It::__bits_per_word;
+    difference_type __n = __last1 - __first1;
+    if (__n > 0)
+    {
+        // do first word
+        if (__first1.__ctz_ != 0)
+        {
+            unsigned __clz = __bits_per_word - __first1.__ctz_;
+            difference_type __dn = _VSTD::min(static_cast<difference_type>(__clz), __n);
+            __n -= __dn;
+            __storage_type __m = (~__storage_type(0) << __first1.__ctz_) & (~__storage_type(0) >> (__clz - __dn));
+            if ((*__first2.__seg_ & __m) != (*__first1.__seg_ & __m))
+                return false;
+            ++__first2.__seg_;
+            ++__first1.__seg_;
+            // __first1.__ctz_ = 0;
+            // __first2.__ctz_ = 0;
+        }
+        // __first1.__ctz_ == 0;
+        // __first2.__ctz_ == 0;
+        // do middle words
+        for (; __n >= __bits_per_word; __n -= __bits_per_word, ++__first1.__seg_, ++__first2.__seg_)
+            if (*__first2.__seg_ != *__first1.__seg_)
+                return false;
+        // do last word
+        if (__n > 0)
+        {
+            __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+            if ((*__first2.__seg_ & __m) != (*__first1.__seg_ & __m))
+                return false;
+        }
+    }
+    return true;
+}
+
+template <class _Cp, bool _IC1, bool _IC2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+equal(__bit_iterator<_Cp, _IC1> __first1, __bit_iterator<_Cp, _IC1> __last1, __bit_iterator<_Cp, _IC2> __first2)
+{
+    if (__first1.__ctz_ == __first2.__ctz_)
+        return _VSTD::__equal_aligned(__first1, __last1, __first2);
+    return _VSTD::__equal_unaligned(__first1, __last1, __first2);
+}
+
+template <class _Cp, bool _IsConst,
+          class>
+class __bit_iterator
+{
+public:
+    typedef typename _Cp::difference_type                                                          difference_type;
+    typedef bool                                                                                  value_type;
+    typedef __bit_iterator                                                                        pointer;
+    typedef typename conditional<_IsConst, __bit_const_reference<_Cp>, __bit_reference<_Cp> >::type reference;
+    typedef random_access_iterator_tag                                                            iterator_category;
+
+private:
+    typedef typename _Cp::__storage_type                                           __storage_type;
+    typedef typename conditional<_IsConst, typename _Cp::__const_storage_pointer,
+                                           typename _Cp::__storage_pointer>::type  __storage_pointer;
+    static const unsigned __bits_per_word = _Cp::__bits_per_word;
+
+    __storage_pointer __seg_;
+    unsigned          __ctz_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY __bit_iterator() _NOEXCEPT
+#if _LIBCPP_STD_VER > 11
+    : __seg_(nullptr), __ctz_(0)
+#endif
+    {}
+
+    // When _IsConst=false, this is the copy constructor.
+    // It is non-trivial. Making it trivial would break ABI.
+    // When _IsConst=true, this is a converting constructor;
+    // the copy and move constructors are implicitly generated
+    // and trivial.
+    _LIBCPP_INLINE_VISIBILITY
+    __bit_iterator(const __bit_iterator<_Cp, false>& __it) _NOEXCEPT
+        : __seg_(__it.__seg_), __ctz_(__it.__ctz_) {}
+
+    // When _IsConst=false, we have a user-provided copy constructor,
+    // so we must also provide a copy assignment operator because
+    // the implicit generation of a defaulted one is deprecated.
+    // When _IsConst=true, the assignment operators are
+    // implicitly generated and trivial.
+    _LIBCPP_INLINE_VISIBILITY
+    __bit_iterator& operator=(const _If<_IsConst, struct __private_nat, __bit_iterator>& __it) {
+        __seg_ = __it.__seg_;
+        __ctz_ = __it.__ctz_;
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY reference operator*() const _NOEXCEPT
+        {return reference(__seg_, __storage_type(1) << __ctz_);}
+
+    _LIBCPP_INLINE_VISIBILITY __bit_iterator& operator++()
+    {
+        if (__ctz_ != __bits_per_word-1)
+            ++__ctz_;
+        else
+        {
+            __ctz_ = 0;
+            ++__seg_;
+        }
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __bit_iterator operator++(int)
+    {
+        __bit_iterator __tmp = *this;
+        ++(*this);
+        return __tmp;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __bit_iterator& operator--()
+    {
+        if (__ctz_ != 0)
+            --__ctz_;
+        else
+        {
+            __ctz_ = __bits_per_word - 1;
+            --__seg_;
+        }
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __bit_iterator operator--(int)
+    {
+        __bit_iterator __tmp = *this;
+        --(*this);
+        return __tmp;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __bit_iterator& operator+=(difference_type __n)
+    {
+        if (__n >= 0)
+            __seg_ += (__n + __ctz_) / __bits_per_word;
+        else
+            __seg_ += static_cast<difference_type>(__n - __bits_per_word + __ctz_ + 1)
+                    / static_cast<difference_type>(__bits_per_word);
+        __n &= (__bits_per_word - 1);
+        __ctz_ = static_cast<unsigned>((__n + __ctz_)  % __bits_per_word);
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __bit_iterator& operator-=(difference_type __n)
+    {
+        return *this += -__n;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __bit_iterator operator+(difference_type __n) const
+    {
+        __bit_iterator __t(*this);
+        __t += __n;
+        return __t;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __bit_iterator operator-(difference_type __n) const
+    {
+        __bit_iterator __t(*this);
+        __t -= __n;
+        return __t;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    friend __bit_iterator operator+(difference_type __n, const __bit_iterator& __it) {return __it + __n;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    friend difference_type operator-(const __bit_iterator& __x, const __bit_iterator& __y)
+        {return (__x.__seg_ - __y.__seg_) * __bits_per_word + __x.__ctz_ - __y.__ctz_;}
+
+    _LIBCPP_INLINE_VISIBILITY reference operator[](difference_type __n) const {return *(*this + __n);}
+
+    _LIBCPP_INLINE_VISIBILITY friend bool operator==(const __bit_iterator& __x, const __bit_iterator& __y)
+        {return __x.__seg_ == __y.__seg_ && __x.__ctz_ == __y.__ctz_;}
+
+    _LIBCPP_INLINE_VISIBILITY friend bool operator!=(const __bit_iterator& __x, const __bit_iterator& __y)
+        {return !(__x == __y);}
+
+    _LIBCPP_INLINE_VISIBILITY friend bool operator<(const __bit_iterator& __x, const __bit_iterator& __y)
+        {return __x.__seg_ < __y.__seg_ || (__x.__seg_ == __y.__seg_ && __x.__ctz_ < __y.__ctz_);}
+
+    _LIBCPP_INLINE_VISIBILITY friend bool operator>(const __bit_iterator& __x, const __bit_iterator& __y)
+        {return __y < __x;}
+
+    _LIBCPP_INLINE_VISIBILITY friend bool operator<=(const __bit_iterator& __x, const __bit_iterator& __y)
+        {return !(__y < __x);}
+
+    _LIBCPP_INLINE_VISIBILITY friend bool operator>=(const __bit_iterator& __x, const __bit_iterator& __y)
+        {return !(__x < __y);}
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    __bit_iterator(__storage_pointer __s, unsigned __ctz) _NOEXCEPT
+        : __seg_(__s), __ctz_(__ctz) {}
+
+    friend typename _Cp::__self;
+
+    friend class __bit_reference<_Cp>;
+    friend class __bit_const_reference<_Cp>;
+    friend class __bit_iterator<_Cp, true>;
+    template <class _Dp> friend struct __bit_array;
+    template <class _Dp> friend void __fill_n_false(__bit_iterator<_Dp, false> __first, typename _Dp::size_type __n);
+    template <class _Dp> friend void __fill_n_true(__bit_iterator<_Dp, false> __first, typename _Dp::size_type __n);
+    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, false> __copy_aligned(__bit_iterator<_Dp, _IC> __first,
+                                                                                  __bit_iterator<_Dp, _IC> __last,
+                                                                                  __bit_iterator<_Dp, false> __result);
+    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, false> __copy_unaligned(__bit_iterator<_Dp, _IC> __first,
+                                                                                    __bit_iterator<_Dp, _IC> __last,
+                                                                                    __bit_iterator<_Dp, false> __result);
+    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, false> copy(__bit_iterator<_Dp, _IC> __first,
+                                                                        __bit_iterator<_Dp, _IC> __last,
+                                                                        __bit_iterator<_Dp, false> __result);
+    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, false> __copy_backward_aligned(__bit_iterator<_Dp, _IC> __first,
+                                                                                           __bit_iterator<_Dp, _IC> __last,
+                                                                                           __bit_iterator<_Dp, false> __result);
+    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, false> __copy_backward_unaligned(__bit_iterator<_Dp, _IC> __first,
+                                                                                             __bit_iterator<_Dp, _IC> __last,
+                                                                                             __bit_iterator<_Dp, false> __result);
+    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, false> copy_backward(__bit_iterator<_Dp, _IC> __first,
+                                                                                 __bit_iterator<_Dp, _IC> __last,
+                                                                                 __bit_iterator<_Dp, false> __result);
+    template <class __C1, class __C2>friend __bit_iterator<__C2, false> __swap_ranges_aligned(__bit_iterator<__C1, false>,
+                                                                                           __bit_iterator<__C1, false>,
+                                                                                           __bit_iterator<__C2, false>);
+    template <class __C1, class __C2>friend __bit_iterator<__C2, false> __swap_ranges_unaligned(__bit_iterator<__C1, false>,
+                                                                                             __bit_iterator<__C1, false>,
+                                                                                             __bit_iterator<__C2, false>);
+    template <class __C1, class __C2>friend __bit_iterator<__C2, false> swap_ranges(__bit_iterator<__C1, false>,
+                                                                                 __bit_iterator<__C1, false>,
+                                                                                 __bit_iterator<__C2, false>);
+    template <class _Dp> friend __bit_iterator<_Dp, false> rotate(__bit_iterator<_Dp, false>,
+                                                                __bit_iterator<_Dp, false>,
+                                                                __bit_iterator<_Dp, false>);
+    template <class _Dp, bool _IC1, bool _IC2> friend bool __equal_aligned(__bit_iterator<_Dp, _IC1>,
+                                                    __bit_iterator<_Dp, _IC1>,
+                                                    __bit_iterator<_Dp, _IC2>);
+    template <class _Dp, bool _IC1, bool _IC2> friend bool __equal_unaligned(__bit_iterator<_Dp, _IC1>,
+                                                      __bit_iterator<_Dp, _IC1>,
+                                                      __bit_iterator<_Dp, _IC2>);
+    template <class _Dp, bool _IC1, bool _IC2> friend bool equal(__bit_iterator<_Dp, _IC1>,
+                                                                __bit_iterator<_Dp, _IC1>,
+                                                                __bit_iterator<_Dp, _IC2>);
+    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, _IC> __find_bool_true(__bit_iterator<_Dp, _IC>,
+                                                                          typename _Dp::size_type);
+    template <class _Dp, bool _IC> friend __bit_iterator<_Dp, _IC> __find_bool_false(__bit_iterator<_Dp, _IC>,
+                                                                           typename _Dp::size_type);
+    template <class _Dp, bool _IC> friend typename __bit_iterator<_Dp, _IC>::difference_type
+                   __count_bool_true(__bit_iterator<_Dp, _IC>, typename _Dp::size_type);
+    template <class _Dp, bool _IC> friend typename __bit_iterator<_Dp, _IC>::difference_type
+                   __count_bool_false(__bit_iterator<_Dp, _IC>, typename _Dp::size_type);
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___BIT_REFERENCE
diff --git a/contrib/libs/cxxsupp/libcxx/include/__bits b/contrib/libs/cxxsupp/libcxx/include/__bits
new file mode 100644
index 00000000000..3a689a86aa1
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__bits
@@ -0,0 +1,149 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___BITS
+#define _LIBCPP___BITS
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_COMPILER_MSVC
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+int __libcpp_ctz(unsigned __x)           _NOEXCEPT { return __builtin_ctz(__x); }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+int __libcpp_ctz(unsigned long __x)      _NOEXCEPT { return __builtin_ctzl(__x); }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+int __libcpp_ctz(unsigned long long __x) _NOEXCEPT { return __builtin_ctzll(__x); }
+
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+int __libcpp_clz(unsigned __x)           _NOEXCEPT { return __builtin_clz(__x); }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+int __libcpp_clz(unsigned long __x)      _NOEXCEPT { return __builtin_clzl(__x); }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+int __libcpp_clz(unsigned long long __x) _NOEXCEPT { return __builtin_clzll(__x); }
+
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+int __libcpp_popcount(unsigned __x)           _NOEXCEPT { return __builtin_popcount(__x); }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+int __libcpp_popcount(unsigned long __x)      _NOEXCEPT { return __builtin_popcountl(__x); }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+int __libcpp_popcount(unsigned long long __x) _NOEXCEPT { return __builtin_popcountll(__x); }
+
+#else  // _LIBCPP_COMPILER_MSVC
+
+// Precondition:  __x != 0
+inline _LIBCPP_INLINE_VISIBILITY
+int __libcpp_ctz(unsigned __x) {
+  static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
+  static_assert(sizeof(unsigned long) == 4, "");
+  unsigned long __where;
+  if (_BitScanForward(&__where, __x))
+    return static_cast<int>(__where);
+  return 32;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+int __libcpp_ctz(unsigned long __x) {
+    static_assert(sizeof(unsigned long) == sizeof(unsigned), "");
+    return __libcpp_ctz(static_cast<unsigned>(__x));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+int __libcpp_ctz(unsigned long long __x) {
+    unsigned long __where;
+#if defined(_LIBCPP_HAS_BITSCAN64)
+  if (_BitScanForward64(&__where, __x))
+    return static_cast<int>(__where);
+#else
+  // Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls.
+  if (_BitScanForward(&__where, static_cast<unsigned long>(__x)))
+    return static_cast<int>(__where);
+  if (_BitScanForward(&__where, static_cast<unsigned long>(__x >> 32)))
+    return static_cast<int>(__where + 32);
+#endif
+  return 64;
+}
+
+// Precondition:  __x != 0
+inline _LIBCPP_INLINE_VISIBILITY
+int __libcpp_clz(unsigned __x) {
+  static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
+  static_assert(sizeof(unsigned long) == 4, "");
+  unsigned long __where;
+  if (_BitScanReverse(&__where, __x))
+    return static_cast<int>(31 - __where);
+  return 32; // Undefined Behavior.
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+int __libcpp_clz(unsigned long __x) {
+    static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
+    return __libcpp_clz(static_cast<unsigned>(__x));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+int __libcpp_clz(unsigned long long __x) {
+  unsigned long __where;
+#if defined(_LIBCPP_HAS_BITSCAN64)
+  if (_BitScanReverse64(&__where, __x))
+    return static_cast<int>(63 - __where);
+#else
+  // Win32 doesn't have _BitScanReverse64 so emulate it with two 32 bit calls.
+  if (_BitScanReverse(&__where, static_cast<unsigned long>(__x >> 32)))
+    return static_cast<int>(63 - (__where + 32));
+  if (_BitScanReverse(&__where, static_cast<unsigned long>(__x)))
+    return static_cast<int>(63 - __where);
+#endif
+  return 64; // Undefined Behavior.
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int __libcpp_popcount(unsigned __x) {
+  static_assert(sizeof(unsigned) == 4, "");
+  return __popcnt(__x);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int __libcpp_popcount(unsigned long __x) {
+  static_assert(sizeof(unsigned long) == 4, "");
+  return __popcnt(__x);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int __libcpp_popcount(unsigned long long __x) {
+  static_assert(sizeof(unsigned long long) == 8, "");
+#if defined(_M_IX86)
+  return __popcnt(__x) + __popcnt(__x >> 32);
+#else
+  return __popcnt64(__x);
+#endif
+}
+
+#endif // _LIBCPP_COMPILER_MSVC
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___BITS
diff --git a/contrib/libs/cxxsupp/libcxx/include/__bsd_locale_defaults.h b/contrib/libs/cxxsupp/libcxx/include/__bsd_locale_defaults.h
new file mode 100644
index 00000000000..18b4599ea65
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__bsd_locale_defaults.h
@@ -0,0 +1,37 @@
+// -*- C++ -*-
+//===---------------------- __bsd_locale_defaults.h -----------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// The BSDs have lots of *_l functions.  We don't want to define those symbols
+// on other platforms though, for fear of conflicts with user code.  So here,
+// we will define the mapping from an internal macro to the real BSD symbol.
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_BSD_LOCALE_DEFAULTS_H
+#define _LIBCPP_BSD_LOCALE_DEFAULTS_H
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#define __libcpp_mb_cur_max_l(loc)                          MB_CUR_MAX_L(loc)
+#define __libcpp_btowc_l(ch, loc)                           btowc_l(ch, loc)
+#define __libcpp_wctob_l(wch, loc)                          wctob_l(wch, loc)
+#define __libcpp_wcsnrtombs_l(dst, src, nwc, len, ps, loc)  wcsnrtombs_l(dst, src, nwc, len, ps, loc)
+#define __libcpp_wcrtomb_l(src, wc, ps, loc)                wcrtomb_l(src, wc, ps, loc)
+#define __libcpp_mbsnrtowcs_l(dst, src, nms, len, ps, loc)  mbsnrtowcs_l(dst, src, nms, len, ps, loc)
+#define __libcpp_mbrtowc_l(pwc, s, n, ps, l)                mbrtowc_l(pwc, s, n, ps, l)
+#define __libcpp_mbtowc_l(pwc, pmb, max, l)                 mbtowc_l(pwc, pmb, max, l)
+#define __libcpp_mbrlen_l(s, n, ps, l)                      mbrlen_l(s, n, ps, l)
+#define __libcpp_localeconv_l(l)                            localeconv_l(l)
+#define __libcpp_mbsrtowcs_l(dest, src, len, ps, l)         mbsrtowcs_l(dest, src, len, ps, l)
+// Workaround for Visual Studio preprocessor bug - explicitly mention all non-variadic parameters.
+#define __libcpp_snprintf_l(__s, __n, __l, __f, ...)        snprintf_l(__s, __n, __l, __f, ##__VA_ARGS__)
+#define __libcpp_asprintf_l(__ret, __l, __f, ...)           asprintf_l(__ret, __l, __f, ##__VA_ARGS__)
+#define __libcpp_sscanf_l(__s, __l, __f, ...)               sscanf_l(__s, __l, __f, ##__VA_ARGS__)
+
+#endif // _LIBCPP_BSD_LOCALE_DEFAULTS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__bsd_locale_fallbacks.h b/contrib/libs/cxxsupp/libcxx/include/__bsd_locale_fallbacks.h
new file mode 100644
index 00000000000..aa64b54c4d0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__bsd_locale_fallbacks.h
@@ -0,0 +1,143 @@
+// -*- C++ -*-
+//===---------------------- __bsd_locale_fallbacks.h ----------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// The BSDs have lots of *_l functions.  This file provides reimplementations
+// of those functions for non-BSD platforms.
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_BSD_LOCALE_FALLBACKS_DEFAULTS_H
+#define _LIBCPP_BSD_LOCALE_FALLBACKS_DEFAULTS_H
+
+#include <memory>
+#include <stdarg.h>
+#include <stdlib.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+inline _LIBCPP_INLINE_VISIBILITY
+decltype(MB_CUR_MAX) __libcpp_mb_cur_max_l(locale_t __l)
+{
+    __libcpp_locale_guard __current(__l);
+    return MB_CUR_MAX;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+inline _LIBCPP_INLINE_VISIBILITY
+wint_t __libcpp_btowc_l(int __c, locale_t __l)
+{
+    __libcpp_locale_guard __current(__l);
+    return btowc(__c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+int __libcpp_wctob_l(wint_t __c, locale_t __l)
+{
+    __libcpp_locale_guard __current(__l);
+    return wctob(__c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+size_t __libcpp_wcsnrtombs_l(char *__dest, const wchar_t **__src, size_t __nwc,
+                         size_t __len, mbstate_t *__ps, locale_t __l)
+{
+    __libcpp_locale_guard __current(__l);
+    return wcsnrtombs(__dest, __src, __nwc, __len, __ps);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+size_t __libcpp_wcrtomb_l(char *__s, wchar_t __wc, mbstate_t *__ps, locale_t __l)
+{
+    __libcpp_locale_guard __current(__l);
+    return wcrtomb(__s, __wc, __ps);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+size_t __libcpp_mbsnrtowcs_l(wchar_t * __dest, const char **__src, size_t __nms,
+                      size_t __len, mbstate_t *__ps, locale_t __l)
+{
+    __libcpp_locale_guard __current(__l);
+    return mbsnrtowcs(__dest, __src, __nms, __len, __ps);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+size_t __libcpp_mbrtowc_l(wchar_t *__pwc, const char *__s, size_t __n,
+                   mbstate_t *__ps, locale_t __l)
+{
+    __libcpp_locale_guard __current(__l);
+    return mbrtowc(__pwc, __s, __n, __ps);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+int __libcpp_mbtowc_l(wchar_t *__pwc, const char *__pmb, size_t __max, locale_t __l)
+{
+    __libcpp_locale_guard __current(__l);
+    return mbtowc(__pwc, __pmb, __max);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+size_t __libcpp_mbrlen_l(const char *__s, size_t __n, mbstate_t *__ps, locale_t __l)
+{
+    __libcpp_locale_guard __current(__l);
+    return mbrlen(__s, __n, __ps);
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+inline _LIBCPP_INLINE_VISIBILITY
+lconv *__libcpp_localeconv_l(locale_t __l)
+{
+    __libcpp_locale_guard __current(__l);
+    return localeconv();
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+inline _LIBCPP_INLINE_VISIBILITY
+size_t __libcpp_mbsrtowcs_l(wchar_t *__dest, const char **__src, size_t __len,
+                     mbstate_t *__ps, locale_t __l)
+{
+    __libcpp_locale_guard __current(__l);
+    return mbsrtowcs(__dest, __src, __len, __ps);
+}
+#endif
+
+inline
+int __libcpp_snprintf_l(char *__s, size_t __n, locale_t __l, const char *__format, ...) {
+    va_list __va;
+    va_start(__va, __format);
+    __libcpp_locale_guard __current(__l);
+    int __res = vsnprintf(__s, __n, __format, __va);
+    va_end(__va);
+    return __res;
+}
+
+inline
+int __libcpp_asprintf_l(char **__s, locale_t __l, const char *__format, ...) {
+    va_list __va;
+    va_start(__va, __format);
+    __libcpp_locale_guard __current(__l);
+    int __res = vasprintf(__s, __format, __va);
+    va_end(__va);
+    return __res;
+}
+
+inline
+int __libcpp_sscanf_l(const char *__s, locale_t __l, const char *__format, ...) {
+    va_list __va;
+    va_start(__va, __format);
+    __libcpp_locale_guard __current(__l);
+    int __res = vsscanf(__s, __format, __va);
+    va_end(__va);
+    return __res;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_BSD_LOCALE_FALLBACKS_DEFAULTS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__charconv/chars_format.h b/contrib/libs/cxxsupp/libcxx/include/__charconv/chars_format.h
new file mode 100644
index 00000000000..22e70b56fb8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__charconv/chars_format.h
@@ -0,0 +1,77 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CHARCONV_CHARS_FORMAT_H
+#define _LIBCPP___CHARCONV_CHARS_FORMAT_H
+
+#include <__config>
+#include <__utility/to_underlying.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_CXX03_LANG
+
+enum class _LIBCPP_ENUM_VIS chars_format
+{
+    scientific = 0x1,
+    fixed = 0x2,
+    hex = 0x4,
+    general = fixed | scientific
+};
+
+inline _LIBCPP_INLINE_VISIBILITY constexpr chars_format
+operator~(chars_format __x) {
+  return chars_format(~_VSTD::__to_underlying(__x));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY constexpr chars_format
+operator&(chars_format __x, chars_format __y) {
+  return chars_format(_VSTD::__to_underlying(__x) &
+                      _VSTD::__to_underlying(__y));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY constexpr chars_format
+operator|(chars_format __x, chars_format __y) {
+  return chars_format(_VSTD::__to_underlying(__x) |
+                      _VSTD::__to_underlying(__y));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY constexpr chars_format
+operator^(chars_format __x, chars_format __y) {
+  return chars_format(_VSTD::__to_underlying(__x) ^
+                      _VSTD::__to_underlying(__y));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 chars_format&
+operator&=(chars_format& __x, chars_format __y) {
+  __x = __x & __y;
+  return __x;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 chars_format&
+operator|=(chars_format& __x, chars_format __y) {
+  __x = __x | __y;
+  return __x;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 chars_format&
+operator^=(chars_format& __x, chars_format __y) {
+  __x = __x ^ __y;
+  return __x;
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CHARCONV_CHARS_FORMAT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__charconv/from_chars_result.h b/contrib/libs/cxxsupp/libcxx/include/__charconv/from_chars_result.h
new file mode 100644
index 00000000000..6d289ba79fd
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__charconv/from_chars_result.h
@@ -0,0 +1,34 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CHARCONV_FROM_CHARS_RESULT_H
+#define _LIBCPP___CHARCONV_FROM_CHARS_RESULT_H
+
+#include <__config>
+#include <__errc>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_CXX03_LANG
+
+struct _LIBCPP_TYPE_VIS from_chars_result
+{
+    const char* ptr;
+    errc ec;
+};
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CHARCONV_FROM_CHARS_RESULT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__charconv/to_chars_result.h b/contrib/libs/cxxsupp/libcxx/include/__charconv/to_chars_result.h
new file mode 100644
index 00000000000..b610a6adcfb
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__charconv/to_chars_result.h
@@ -0,0 +1,34 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CHARCONV_TO_CHARS_RESULT_H
+#define _LIBCPP___CHARCONV_TO_CHARS_RESULT_H
+
+#include <__config>
+#include <__errc>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_CXX03_LANG
+
+struct _LIBCPP_TYPE_VIS to_chars_result
+{
+    char* ptr;
+    errc ec;
+};
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CHARCONV_TO_CHARS_RESULT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__compare/common_comparison_category.h b/contrib/libs/cxxsupp/libcxx/include/__compare/common_comparison_category.h
new file mode 100644
index 00000000000..09afb06243e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__compare/common_comparison_category.h
@@ -0,0 +1,94 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___COMPARE_COMMON_COMPARISON_CATEGORY_H
+#define _LIBCPP___COMPARE_COMMON_COMPARISON_CATEGORY_H
+
+#include <__compare/ordering.h>
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR)
+
+namespace __comp_detail {
+
+enum _ClassifyCompCategory : unsigned {
+  _None,
+  _PartialOrd,
+  _WeakOrd,
+  _StrongOrd,
+  _CCC_Size
+};
+
+template <class _Tp>
+_LIBCPP_HIDE_FROM_ABI
+constexpr _ClassifyCompCategory __type_to_enum() noexcept {
+  if (is_same_v<_Tp, partial_ordering>)
+    return _PartialOrd;
+  if (is_same_v<_Tp, weak_ordering>)
+    return _WeakOrd;
+  if (is_same_v<_Tp, strong_ordering>)
+    return _StrongOrd;
+  return _None;
+}
+
+template <size_t _Size>
+_LIBCPP_HIDE_FROM_ABI
+constexpr _ClassifyCompCategory
+__compute_comp_type(const _ClassifyCompCategory (&__types)[_Size]) {
+  int __seen[_CCC_Size] = {};
+  for (auto __type : __types)
+    ++__seen[__type];
+  if (__seen[_None])
+    return _None;
+  if (__seen[_PartialOrd])
+    return _PartialOrd;
+  if (__seen[_WeakOrd])
+    return _WeakOrd;
+  return _StrongOrd;
+}
+
+template <class ..._Ts, bool _False = false>
+_LIBCPP_HIDE_FROM_ABI
+constexpr auto __get_comp_type() {
+  using _CCC = _ClassifyCompCategory;
+  constexpr _CCC __type_kinds[] = {_StrongOrd, __type_to_enum<_Ts>()...};
+  constexpr _CCC _Cat = __compute_comp_type(__type_kinds);
+  if constexpr (_Cat == _None)
+    return void();
+  else if constexpr (_Cat == _PartialOrd)
+    return partial_ordering::equivalent;
+  else if constexpr (_Cat == _WeakOrd)
+    return weak_ordering::equivalent;
+  else if constexpr (_Cat == _StrongOrd)
+    return strong_ordering::equivalent;
+  else
+    static_assert(_False, "unhandled case");
+}
+} // namespace __comp_detail
+
+// [cmp.common], common comparison category type
+template<class... _Ts>
+struct _LIBCPP_TEMPLATE_VIS common_comparison_category {
+  using type = decltype(__comp_detail::__get_comp_type<_Ts...>());
+};
+
+template<class... _Ts>
+using common_comparison_category_t = typename common_comparison_category<_Ts...>::type;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___COMPARE_COMMON_COMPARISON_CATEGORY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__compare/compare_three_way.h b/contrib/libs/cxxsupp/libcxx/include/__compare/compare_three_way.h
new file mode 100644
index 00000000000..492908a3a0d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__compare/compare_three_way.h
@@ -0,0 +1,41 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___COMPARE_COMPARE_THREE_WAY_H
+#define _LIBCPP___COMPARE_COMPARE_THREE_WAY_H
+
+#include <__config>
+#include <__compare/three_way_comparable.h>
+#include <__utility/forward.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR) && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+struct _LIBCPP_TEMPLATE_VIS compare_three_way
+{
+    template<class _T1, class _T2>
+        requires three_way_comparable_with<_T1, _T2>
+    constexpr _LIBCPP_HIDE_FROM_ABI
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) <=> _VSTD::forward<_T2>(__u)))
+        { return          _VSTD::forward<_T1>(__t) <=> _VSTD::forward<_T2>(__u); }
+
+    using is_transparent = void;
+};
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR) && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___COMPARE_COMPARE_THREE_WAY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__compare/compare_three_way_result.h b/contrib/libs/cxxsupp/libcxx/include/__compare/compare_three_way_result.h
new file mode 100644
index 00000000000..14908c6bbc1
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__compare/compare_three_way_result.h
@@ -0,0 +1,43 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H
+#define _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+template<class, class, class>
+struct _LIBCPP_HIDE_FROM_ABI __compare_three_way_result { };
+
+template<class _Tp, class _Up>
+struct _LIBCPP_HIDE_FROM_ABI __compare_three_way_result<_Tp, _Up, decltype(
+  declval<__make_const_lvalue_ref<_Tp>>() <=> declval<__make_const_lvalue_ref<_Up>>(), void()
+)> {
+    using type = decltype(declval<__make_const_lvalue_ref<_Tp>>() <=> declval<__make_const_lvalue_ref<_Up>>());
+};
+
+template<class _Tp, class _Up = _Tp>
+struct _LIBCPP_TEMPLATE_VIS compare_three_way_result : __compare_three_way_result<_Tp, _Up, void> { };
+
+template<class _Tp, class _Up = _Tp>
+using compare_three_way_result_t = typename compare_three_way_result<_Tp, _Up>::type;
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__compare/is_eq.h b/contrib/libs/cxxsupp/libcxx/include/__compare/is_eq.h
new file mode 100644
index 00000000000..ae2af51d859
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__compare/is_eq.h
@@ -0,0 +1,34 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___COMPARE_IS_EQ_H
+#define _LIBCPP___COMPARE_IS_EQ_H
+
+#include <__compare/ordering.h>
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR)
+
+_LIBCPP_HIDE_FROM_ABI inline constexpr bool is_eq(partial_ordering __c) noexcept { return __c == 0; }
+_LIBCPP_HIDE_FROM_ABI inline constexpr bool is_neq(partial_ordering __c) noexcept { return __c != 0; }
+_LIBCPP_HIDE_FROM_ABI inline constexpr bool is_lt(partial_ordering __c) noexcept { return __c < 0; }
+_LIBCPP_HIDE_FROM_ABI inline constexpr bool is_lteq(partial_ordering __c) noexcept { return __c <= 0; }
+_LIBCPP_HIDE_FROM_ABI inline constexpr bool is_gt(partial_ordering __c) noexcept { return __c > 0; }
+_LIBCPP_HIDE_FROM_ABI inline constexpr bool is_gteq(partial_ordering __c) noexcept { return __c >= 0; }
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___COMPARE_IS_EQ_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__compare/ordering.h b/contrib/libs/cxxsupp/libcxx/include/__compare/ordering.h
new file mode 100644
index 00000000000..2cab8b9a2ed
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__compare/ordering.h
@@ -0,0 +1,330 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___COMPARE_ORDERING_H
+#define _LIBCPP___COMPARE_ORDERING_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#if defined(_MSC_VER) && !defined(__clang__)
+// Omit inline namespace __y1, as MSVC2019 fails to find ordering classes
+// inside the inlined namespace when compiling the <=> operators.
+// See CROWDFUNDING-6 for the details.
+namespace std {
+#else
+_LIBCPP_BEGIN_NAMESPACE_STD
+#endif
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR)
+
+// exposition only
+enum class _LIBCPP_ENUM_VIS _OrdResult : signed char {
+  __less = -1,
+  __equiv = 0,
+  __greater = 1
+};
+
+enum class _LIBCPP_ENUM_VIS _NCmpResult : signed char {
+  __unordered = -127
+};
+
+class partial_ordering;
+class weak_ordering;
+class strong_ordering;
+
+template<class _Tp, class... _Args>
+inline constexpr bool __one_of_v = (is_same_v<_Tp, _Args> || ...);
+
+struct _CmpUnspecifiedParam {
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEVAL
+  _CmpUnspecifiedParam(int _CmpUnspecifiedParam::*) noexcept {}
+
+  template<class _Tp, class = enable_if_t<!__one_of_v<_Tp, int, partial_ordering, weak_ordering, strong_ordering>>>
+  _CmpUnspecifiedParam(_Tp) = delete;
+};
+
+class partial_ordering {
+  using _ValueT = signed char;
+
+  _LIBCPP_HIDE_FROM_ABI
+  explicit constexpr partial_ordering(_OrdResult __v) noexcept
+      : __value_(_ValueT(__v)) {}
+
+  _LIBCPP_HIDE_FROM_ABI
+  explicit constexpr partial_ordering(_NCmpResult __v) noexcept
+      : __value_(_ValueT(__v)) {}
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr bool __is_ordered() const noexcept {
+    return __value_ != _ValueT(_NCmpResult::__unordered);
+  }
+public:
+  // valid values
+  static const partial_ordering less;
+  static const partial_ordering equivalent;
+  static const partial_ordering greater;
+  static const partial_ordering unordered;
+
+  // comparisons
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator==(partial_ordering, partial_ordering) noexcept = default;
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator==(partial_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v.__is_ordered() && __v.__value_ == 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator< (partial_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v.__is_ordered() && __v.__value_ < 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator<=(partial_ordering __v, _CmpUnspecifiedParam) noexcept  {
+    return __v.__is_ordered() && __v.__value_ <= 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator> (partial_ordering __v, _CmpUnspecifiedParam) noexcept  {
+    return __v.__is_ordered() && __v.__value_ > 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator>=(partial_ordering __v, _CmpUnspecifiedParam) noexcept  {
+    return __v.__is_ordered() && __v.__value_ >= 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator< (_CmpUnspecifiedParam, partial_ordering __v) noexcept  {
+    return __v.__is_ordered() && 0 < __v.__value_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator<=(_CmpUnspecifiedParam, partial_ordering __v) noexcept  {
+    return __v.__is_ordered() && 0 <= __v.__value_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator> (_CmpUnspecifiedParam, partial_ordering __v) noexcept  {
+    return __v.__is_ordered() && 0 > __v.__value_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator>=(_CmpUnspecifiedParam, partial_ordering __v) noexcept  {
+    return __v.__is_ordered() && 0 >= __v.__value_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr partial_ordering operator<=>(partial_ordering __v, _CmpUnspecifiedParam) noexcept  {
+    return __v;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr partial_ordering operator<=>(_CmpUnspecifiedParam, partial_ordering __v) noexcept  {
+    return __v < 0 ? partial_ordering::greater : (__v > 0 ? partial_ordering::less : __v);
+  }
+private:
+  _ValueT __value_;
+};
+
+inline constexpr partial_ordering partial_ordering::less(_OrdResult::__less);
+inline constexpr partial_ordering partial_ordering::equivalent(_OrdResult::__equiv);
+inline constexpr partial_ordering partial_ordering::greater(_OrdResult::__greater);
+inline constexpr partial_ordering partial_ordering::unordered(_NCmpResult ::__unordered);
+
+class weak_ordering {
+  using _ValueT = signed char;
+
+  _LIBCPP_HIDE_FROM_ABI
+  explicit constexpr weak_ordering(_OrdResult __v) noexcept : __value_(_ValueT(__v)) {}
+
+public:
+  static const weak_ordering less;
+  static const weak_ordering equivalent;
+  static const weak_ordering greater;
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr operator partial_ordering() const noexcept {
+    return __value_ == 0 ? partial_ordering::equivalent
+        : (__value_ < 0 ? partial_ordering::less : partial_ordering::greater);
+  }
+
+  // comparisons
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator==(weak_ordering, weak_ordering) noexcept = default;
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator==(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v.__value_ == 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator< (weak_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v.__value_ < 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator<=(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v.__value_ <= 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator> (weak_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v.__value_ > 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator>=(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v.__value_ >= 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator< (_CmpUnspecifiedParam, weak_ordering __v) noexcept {
+    return 0 < __v.__value_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator<=(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
+    return 0 <= __v.__value_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator> (_CmpUnspecifiedParam, weak_ordering __v) noexcept {
+    return 0 > __v.__value_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator>=(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
+    return 0 >= __v.__value_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr weak_ordering operator<=>(weak_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr weak_ordering operator<=>(_CmpUnspecifiedParam, weak_ordering __v) noexcept {
+    return __v < 0 ? weak_ordering::greater : (__v > 0 ? weak_ordering::less : __v);
+  }
+
+private:
+  _ValueT __value_;
+};
+
+inline constexpr weak_ordering weak_ordering::less(_OrdResult::__less);
+inline constexpr weak_ordering weak_ordering::equivalent(_OrdResult::__equiv);
+inline constexpr weak_ordering weak_ordering::greater(_OrdResult::__greater);
+
+class strong_ordering {
+  using _ValueT = signed char;
+
+  _LIBCPP_HIDE_FROM_ABI
+  explicit constexpr strong_ordering(_OrdResult __v) noexcept : __value_(_ValueT(__v)) {}
+
+public:
+  static const strong_ordering less;
+  static const strong_ordering equal;
+  static const strong_ordering equivalent;
+  static const strong_ordering greater;
+
+  // conversions
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr operator partial_ordering() const noexcept {
+    return __value_ == 0 ? partial_ordering::equivalent
+        : (__value_ < 0 ? partial_ordering::less : partial_ordering::greater);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr operator weak_ordering() const noexcept {
+    return __value_ == 0 ? weak_ordering::equivalent
+        : (__value_ < 0 ? weak_ordering::less : weak_ordering::greater);
+  }
+
+  // comparisons
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator==(strong_ordering, strong_ordering) noexcept = default;
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator==(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v.__value_ == 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator< (strong_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v.__value_ < 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator<=(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v.__value_ <= 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator> (strong_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v.__value_ > 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator>=(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v.__value_ >= 0;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator< (_CmpUnspecifiedParam, strong_ordering __v) noexcept {
+    return 0 < __v.__value_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator<=(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
+    return 0 <= __v.__value_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator> (_CmpUnspecifiedParam, strong_ordering __v) noexcept {
+    return 0 > __v.__value_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator>=(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
+    return 0 >= __v.__value_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr strong_ordering operator<=>(strong_ordering __v, _CmpUnspecifiedParam) noexcept {
+    return __v;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr strong_ordering operator<=>(_CmpUnspecifiedParam, strong_ordering __v) noexcept {
+    return __v < 0 ? strong_ordering::greater : (__v > 0 ? strong_ordering::less : __v);
+  }
+
+private:
+  _ValueT __value_;
+};
+
+inline constexpr strong_ordering strong_ordering::less(_OrdResult::__less);
+inline constexpr strong_ordering strong_ordering::equal(_OrdResult::__equiv);
+inline constexpr strong_ordering strong_ordering::equivalent(_OrdResult::__equiv);
+inline constexpr strong_ordering strong_ordering::greater(_OrdResult::__greater);
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR)
+
+#if defined(_MSC_VER) && !defined(__clang__)
+}
+#else
+_LIBCPP_END_NAMESPACE_STD
+#endif
+
+#endif // _LIBCPP___COMPARE_ORDERING_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__compare/synth_three_way.h b/contrib/libs/cxxsupp/libcxx/include/__compare/synth_three_way.h
new file mode 100644
index 00000000000..cc0b0f2c2af
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__compare/synth_three_way.h
@@ -0,0 +1,51 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___COMPARE_SYNTH_THREE_WAY_H
+#define _LIBCPP___COMPARE_SYNTH_THREE_WAY_H
+
+#include <__config>
+#include <__compare/ordering.h>
+#include <__compare/three_way_comparable.h>
+#include <__concepts/boolean_testable.h>
+#include <__utility/declval.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR) && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [expos.only.func]
+
+_LIBCPP_HIDE_FROM_ABI inline constexpr auto __synth_three_way =
+  []<class _Tp, class _Up>(const _Tp& __t, const _Up& __u)
+    requires requires {
+      { __t < __u } -> __boolean_testable;
+      { __u < __t } -> __boolean_testable;
+    }
+  {
+    if constexpr (three_way_comparable_with<_Tp, _Up>) {
+      return __t <=> __u;
+    } else {
+      if (__t < __u) return weak_ordering::less;
+      if (__u < __t) return weak_ordering::greater;
+      return weak_ordering::equivalent;
+    }
+  };
+
+template <class _Tp, class _Up = _Tp>
+using __synth_three_way_result = decltype(__synth_three_way(declval<_Tp&>(), declval<_Up&>()));
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR) && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___COMPARE_SYNTH_THREE_WAY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__compare/three_way_comparable.h b/contrib/libs/cxxsupp/libcxx/include/__compare/three_way_comparable.h
new file mode 100644
index 00000000000..2560cf64024
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__compare/three_way_comparable.h
@@ -0,0 +1,58 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___COMPARE_THREE_WAY_COMPARABLE_H
+#define _LIBCPP___COMPARE_THREE_WAY_COMPARABLE_H
+
+#include <__compare/common_comparison_category.h>
+#include <__compare/ordering.h>
+#include <__concepts/common_reference_with.h>
+#include <__concepts/equality_comparable.h>
+#include <__concepts/same_as.h>
+#include <__concepts/totally_ordered.h>
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR) && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+template<class _Tp, class _Cat>
+concept __compares_as =
+  same_as<common_comparison_category_t<_Tp, _Cat>, _Cat>;
+
+template<class _Tp, class _Cat = partial_ordering>
+concept three_way_comparable =
+  __weakly_equality_comparable_with<_Tp, _Tp> &&
+  __partially_ordered_with<_Tp, _Tp> &&
+  requires(__make_const_lvalue_ref<_Tp> __a, __make_const_lvalue_ref<_Tp> __b) {
+    { __a <=> __b } -> __compares_as<_Cat>;
+  };
+
+template<class _Tp, class _Up, class _Cat = partial_ordering>
+concept three_way_comparable_with =
+  three_way_comparable<_Tp, _Cat> &&
+  three_way_comparable<_Up, _Cat> &&
+  common_reference_with<__make_const_lvalue_ref<_Tp>, __make_const_lvalue_ref<_Up>> &&
+  three_way_comparable<common_reference_t<__make_const_lvalue_ref<_Tp>, __make_const_lvalue_ref<_Up>>, _Cat> &&
+  __weakly_equality_comparable_with<_Tp, _Up> &&
+  __partially_ordered_with<_Tp, _Up> &&
+  requires(__make_const_lvalue_ref<_Tp> __t, __make_const_lvalue_ref<_Up> __u) {
+    { __t <=> __u } -> __compares_as<_Cat>;
+    { __u <=> __t } -> __compares_as<_Cat>;
+  };
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR) && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___COMPARE_THREE_WAY_COMPARABLE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/arithmetic.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/arithmetic.h
new file mode 100644
index 00000000000..9a1383904db
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/arithmetic.h
@@ -0,0 +1,48 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_ARITHMETIC_H
+#define _LIBCPP___CONCEPTS_ARITHMETIC_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concepts.arithmetic], arithmetic concepts
+
+template<class _Tp>
+concept integral = is_integral_v<_Tp>;
+
+template<class _Tp>
+concept signed_integral = integral<_Tp> && is_signed_v<_Tp>;
+
+template<class _Tp>
+concept unsigned_integral = integral<_Tp> && !signed_integral<_Tp>;
+
+template<class _Tp>
+concept floating_point = is_floating_point_v<_Tp>;
+
+// Concept helpers for the internal type traits for the fundamental types.
+
+template <class _Tp>
+concept __libcpp_unsigned_integer = __libcpp_is_unsigned_integer<_Tp>::value;
+template <class _Tp>
+concept __libcpp_signed_integer = __libcpp_is_signed_integer<_Tp>::value;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_ARITHMETIC_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/assignable.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/assignable.h
new file mode 100644
index 00000000000..9cfc7c0e831
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/assignable.h
@@ -0,0 +1,40 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_ASSIGNABLE_H
+#define _LIBCPP___CONCEPTS_ASSIGNABLE_H
+
+#include <__concepts/common_reference_with.h>
+#include <__concepts/same_as.h>
+#include <__config>
+#include <__utility/forward.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.assignable]
+
+template<class _Lhs, class _Rhs>
+concept assignable_from =
+  is_lvalue_reference_v<_Lhs> &&
+  common_reference_with<__make_const_lvalue_ref<_Lhs>, __make_const_lvalue_ref<_Rhs>> &&
+  requires (_Lhs __lhs, _Rhs&& __rhs) {
+    { __lhs = _VSTD::forward<_Rhs>(__rhs) } -> same_as<_Lhs>;
+  };
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_ASSIGNABLE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/boolean_testable.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/boolean_testable.h
new file mode 100644
index 00000000000..638fc3b2033
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/boolean_testable.h
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_BOOLEAN_TESTABLE_H
+#define _LIBCPP___CONCEPTS_BOOLEAN_TESTABLE_H
+
+#include <__concepts/convertible_to.h>
+#include <__config>
+#include <__utility/forward.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concepts.booleantestable]
+
+template<class _Tp>
+concept __boolean_testable_impl = convertible_to<_Tp, bool>;
+
+template<class _Tp>
+concept __boolean_testable = __boolean_testable_impl<_Tp> && requires(_Tp&& __t) {
+  { !_VSTD::forward<_Tp>(__t) } -> __boolean_testable_impl;
+};
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_BOOLEAN_TESTABLE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/class_or_enum.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/class_or_enum.h
new file mode 100644
index 00000000000..43c7636d9c8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/class_or_enum.h
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_CLASS_OR_ENUM_H
+#define _LIBCPP___CONCEPTS_CLASS_OR_ENUM_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// Whether a type is a class type or enumeration type according to the Core wording.
+
+template<class _Tp>
+concept __class_or_enum = is_class_v<_Tp> || is_union_v<_Tp> || is_enum_v<_Tp>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_CLASS_OR_ENUM_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/common_reference_with.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/common_reference_with.h
new file mode 100644
index 00000000000..3269e3ae89f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/common_reference_with.h
@@ -0,0 +1,37 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_COMMON_REFERENCE_WITH_H
+#define _LIBCPP___CONCEPTS_COMMON_REFERENCE_WITH_H
+
+#include <__concepts/convertible_to.h>
+#include <__concepts/same_as.h>
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.commonref]
+
+template<class _Tp, class _Up>
+concept common_reference_with =
+  same_as<common_reference_t<_Tp, _Up>, common_reference_t<_Up, _Tp>> &&
+  convertible_to<_Tp, common_reference_t<_Tp, _Up>> &&
+  convertible_to<_Up, common_reference_t<_Tp, _Up>>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_COMMON_REFERENCE_WITH_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/common_with.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/common_with.h
new file mode 100644
index 00000000000..b575aea5f77
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/common_with.h
@@ -0,0 +1,47 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_COMMON_WITH_H
+#define _LIBCPP___CONCEPTS_COMMON_WITH_H
+
+#include <__concepts/common_reference_with.h>
+#include <__concepts/same_as.h>
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.common]
+
+template<class _Tp, class _Up>
+concept common_with =
+  same_as<common_type_t<_Tp, _Up>, common_type_t<_Up, _Tp>> &&
+  requires {
+    static_cast<common_type_t<_Tp, _Up>>(declval<_Tp>());
+    static_cast<common_type_t<_Tp, _Up>>(declval<_Up>());
+  } &&
+  common_reference_with<
+    add_lvalue_reference_t<const _Tp>,
+    add_lvalue_reference_t<const _Up>> &&
+  common_reference_with<
+    add_lvalue_reference_t<common_type_t<_Tp, _Up>>,
+    common_reference_t<
+      add_lvalue_reference_t<const _Tp>,
+      add_lvalue_reference_t<const _Up>>>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_COMMON_WITH_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/constructible.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/constructible.h
new file mode 100644
index 00000000000..9bba8118b89
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/constructible.h
@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_CONSTRUCTIBLE_H
+#define _LIBCPP___CONCEPTS_CONSTRUCTIBLE_H
+
+#include <__concepts/convertible_to.h>
+#include <__concepts/destructible.h>
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.constructible]
+template<class _Tp, class... _Args>
+concept constructible_from =
+    destructible<_Tp> && is_constructible_v<_Tp, _Args...>;
+
+// [concept.default.init]
+
+template<class _Tp>
+concept __default_initializable = requires { ::new _Tp; };
+
+template<class _Tp>
+concept default_initializable = constructible_from<_Tp> &&
+    requires { _Tp{}; } && __default_initializable<_Tp>;
+
+// [concept.moveconstructible]
+template<class _Tp>
+concept move_constructible =
+  constructible_from<_Tp, _Tp> && convertible_to<_Tp, _Tp>;
+
+// [concept.copyconstructible]
+template<class _Tp>
+concept copy_constructible =
+  move_constructible<_Tp> &&
+  constructible_from<_Tp, _Tp&> && convertible_to<_Tp&, _Tp> &&
+  constructible_from<_Tp, const _Tp&> && convertible_to<const _Tp&, _Tp> &&
+  constructible_from<_Tp, const _Tp> && convertible_to<const _Tp, _Tp>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_CONSTRUCTIBLE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/convertible_to.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/convertible_to.h
new file mode 100644
index 00000000000..ec68967106d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/convertible_to.h
@@ -0,0 +1,36 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_CONVERTIBLE_TO_H
+#define _LIBCPP___CONCEPTS_CONVERTIBLE_TO_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.convertible]
+
+template<class _From, class _To>
+concept convertible_to =
+  is_convertible_v<_From, _To> &&
+  requires (add_rvalue_reference_t<_From> (&__f)()) {
+    static_cast<_To>(__f());
+  };
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_CONVERTIBLE_TO_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/copyable.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/copyable.h
new file mode 100644
index 00000000000..cfeeec86917
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/copyable.h
@@ -0,0 +1,39 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_COPYABLE_H
+#define _LIBCPP___CONCEPTS_COPYABLE_H
+
+#include <__concepts/assignable.h>
+#include <__concepts/constructible.h>
+#include <__concepts/movable.h>
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concepts.object]
+
+template<class _Tp>
+concept copyable =
+  copy_constructible<_Tp> &&
+  movable<_Tp> &&
+  assignable_from<_Tp&, _Tp&> &&
+  assignable_from<_Tp&, const _Tp&> &&
+  assignable_from<_Tp&, const _Tp>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_COPYABLE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/derived_from.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/derived_from.h
new file mode 100644
index 00000000000..f7c83bf31fb
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/derived_from.h
@@ -0,0 +1,34 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_DERIVED_FROM_H
+#define _LIBCPP___CONCEPTS_DERIVED_FROM_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.derived]
+
+template<class _Dp, class _Bp>
+concept derived_from =
+  is_base_of_v<_Bp, _Dp> &&
+  is_convertible_v<const volatile _Dp*, const volatile _Bp*>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_DERIVED_FROM_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/destructible.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/destructible.h
new file mode 100644
index 00000000000..800ee2d56f0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/destructible.h
@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_DESTRUCTIBLE_H
+#define _LIBCPP___CONCEPTS_DESTRUCTIBLE_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.destructible]
+
+template<class _Tp>
+concept destructible = is_nothrow_destructible_v<_Tp>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_DESTRUCTIBLE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/different_from.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/different_from.h
new file mode 100644
index 00000000000..5def31e652a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/different_from.h
@@ -0,0 +1,31 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_DIFFERENT_FROM_H
+#define _LIBCPP___CONCEPTS_DIFFERENT_FROM_H
+
+#include <__concepts/same_as.h>
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+template<class _Tp, class _Up>
+concept __different_from = !same_as<remove_cvref_t<_Tp>, remove_cvref_t<_Up>>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_DIFFERENT_FROM_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/equality_comparable.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/equality_comparable.h
new file mode 100644
index 00000000000..5df812c2600
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/equality_comparable.h
@@ -0,0 +1,53 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_EQUALITY_COMPARABLE_H
+#define _LIBCPP___CONCEPTS_EQUALITY_COMPARABLE_H
+
+#include <__concepts/boolean_testable.h>
+#include <__concepts/common_reference_with.h>
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.equalitycomparable]
+
+template<class _Tp, class _Up>
+concept __weakly_equality_comparable_with =
+  requires(__make_const_lvalue_ref<_Tp> __t, __make_const_lvalue_ref<_Up> __u) {
+    { __t == __u } -> __boolean_testable;
+    { __t != __u } -> __boolean_testable;
+    { __u == __t } -> __boolean_testable;
+    { __u != __t } -> __boolean_testable;
+  };
+
+template<class _Tp>
+concept equality_comparable = __weakly_equality_comparable_with<_Tp, _Tp>;
+
+template<class _Tp, class _Up>
+concept equality_comparable_with =
+  equality_comparable<_Tp> && equality_comparable<_Up> &&
+  common_reference_with<__make_const_lvalue_ref<_Tp>, __make_const_lvalue_ref<_Up>> &&
+  equality_comparable<
+    common_reference_t<
+      __make_const_lvalue_ref<_Tp>,
+      __make_const_lvalue_ref<_Up>>> &&
+  __weakly_equality_comparable_with<_Tp, _Up>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_EQUALITY_COMPARABLE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/invocable.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/invocable.h
new file mode 100644
index 00000000000..0a8d9b7255a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/invocable.h
@@ -0,0 +1,41 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_INVOCABLE_H
+#define _LIBCPP___CONCEPTS_INVOCABLE_H
+
+#include <__config>
+#include <__functional/invoke.h>
+#include <__utility/forward.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.invocable]
+
+template<class _Fn, class... _Args>
+concept invocable = requires(_Fn&& __fn, _Args&&... __args) {
+  _VSTD::invoke(_VSTD::forward<_Fn>(__fn), _VSTD::forward<_Args>(__args)...); // not required to be equality preserving
+};
+
+// [concept.regular.invocable]
+
+template<class _Fn, class... _Args>
+concept regular_invocable = invocable<_Fn, _Args...>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_INVOCABLE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/movable.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/movable.h
new file mode 100644
index 00000000000..dd0b8fb56d5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/movable.h
@@ -0,0 +1,39 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_MOVABLE_H
+#define _LIBCPP___CONCEPTS_MOVABLE_H
+
+#include <__concepts/assignable.h>
+#include <__concepts/constructible.h>
+#include <__concepts/swappable.h>
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concepts.object]
+
+template<class _Tp>
+concept movable =
+  is_object_v<_Tp> &&
+  move_constructible<_Tp> &&
+  assignable_from<_Tp&, _Tp> &&
+  swappable<_Tp>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_MOVABLE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/predicate.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/predicate.h
new file mode 100644
index 00000000000..8e885406316
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/predicate.h
@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_PREDICATE_H
+#define _LIBCPP___CONCEPTS_PREDICATE_H
+
+#include <__concepts/boolean_testable.h>
+#include <__concepts/invocable.h>
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.predicate]
+
+template<class _Fn, class... _Args>
+concept predicate =
+  regular_invocable<_Fn, _Args...> && __boolean_testable<invoke_result_t<_Fn, _Args...>>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_PREDICATE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/regular.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/regular.h
new file mode 100644
index 00000000000..d292e8d72db
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/regular.h
@@ -0,0 +1,33 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_REGULAR_H
+#define _LIBCPP___CONCEPTS_REGULAR_H
+
+#include <__concepts/equality_comparable.h>
+#include <__concepts/semiregular.h>
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.object]
+
+template<class _Tp>
+concept regular = semiregular<_Tp> && equality_comparable<_Tp>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_REGULAR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/relation.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/relation.h
new file mode 100644
index 00000000000..c6ff20d1519
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/relation.h
@@ -0,0 +1,44 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_RELATION_H
+#define _LIBCPP___CONCEPTS_RELATION_H
+
+#include <__concepts/predicate.h>
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.relation]
+
+template<class _Rp, class _Tp, class _Up>
+concept relation =
+  predicate<_Rp, _Tp, _Tp> && predicate<_Rp, _Up, _Up> &&
+  predicate<_Rp, _Tp, _Up> && predicate<_Rp, _Up, _Tp>;
+
+// [concept.equiv]
+
+template<class _Rp, class _Tp, class _Up>
+concept equivalence_relation = relation<_Rp, _Tp, _Up>;
+
+// [concept.strictweakorder]
+
+template<class _Rp, class _Tp, class _Up>
+concept strict_weak_order = relation<_Rp, _Tp, _Up>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_RELATION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/same_as.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/same_as.h
new file mode 100644
index 00000000000..5a912b6f41c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/same_as.h
@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_SAME_AS_H
+#define _LIBCPP___CONCEPTS_SAME_AS_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.same]
+
+template<class _Tp, class _Up>
+concept __same_as_impl = _IsSame<_Tp, _Up>::value;
+
+template<class _Tp, class _Up>
+concept same_as = __same_as_impl<_Tp, _Up> && __same_as_impl<_Up, _Tp>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_SAME_AS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/semiregular.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/semiregular.h
new file mode 100644
index 00000000000..4b96fe6dfba
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/semiregular.h
@@ -0,0 +1,33 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_SEMIREGULAR_H
+#define _LIBCPP___CONCEPTS_SEMIREGULAR_H
+
+#include <__concepts/constructible.h>
+#include <__concepts/copyable.h>
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.object]
+
+template<class _Tp>
+concept semiregular = copyable<_Tp> && default_initializable<_Tp>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_SEMIREGULAR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/swappable.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/swappable.h
new file mode 100644
index 00000000000..423b3a89fa4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/swappable.h
@@ -0,0 +1,115 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_SWAPPABLE_H
+#define _LIBCPP___CONCEPTS_SWAPPABLE_H
+
+#include <__concepts/assignable.h>
+#include <__concepts/class_or_enum.h>
+#include <__concepts/common_reference_with.h>
+#include <__concepts/constructible.h>
+#include <__config>
+#include <__utility/exchange.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.swappable]
+namespace ranges::__swap {
+  // Deleted to inhibit ADL
+  template<class _Tp>
+  void swap(_Tp&, _Tp&) = delete;
+
+
+  // [1]
+  template<class _Tp, class _Up>
+  concept __unqualified_swappable_with =
+    (__class_or_enum<remove_cvref_t<_Tp>> || __class_or_enum<remove_cvref_t<_Up>>) &&
+    requires(_Tp&& __t, _Up&& __u) {
+      swap(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u));
+    };
+
+  struct __fn;
+
+  template<class _Tp, class _Up, size_t _Size>
+  concept __swappable_arrays =
+    !__unqualified_swappable_with<_Tp(&)[_Size], _Up(&)[_Size]> &&
+    extent_v<_Tp> == extent_v<_Up> &&
+    requires(_Tp(& __t)[_Size], _Up(& __u)[_Size], const __fn& __swap) {
+      __swap(__t[0], __u[0]);
+    };
+
+  template<class _Tp>
+  concept __exchangeable =
+    !__unqualified_swappable_with<_Tp&, _Tp&> &&
+    move_constructible<_Tp> &&
+    assignable_from<_Tp&, _Tp>;
+
+  struct __fn {
+    // 2.1   `S` is `(void)swap(E1, E2)`* if `E1` or `E2` has class or enumeration type and...
+    // *The name `swap` is used here unqualified.
+    template<class _Tp, class _Up>
+      requires __unqualified_swappable_with<_Tp, _Up>
+    constexpr void operator()(_Tp&& __t, _Up&& __u) const
+      noexcept(noexcept(swap(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u))))
+    {
+      swap(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u));
+    }
+
+    // 2.2   Otherwise, if `E1` and `E2` are lvalues of array types with equal extent and...
+    template<class _Tp, class _Up, size_t _Size>
+      requires __swappable_arrays<_Tp, _Up, _Size>
+    constexpr void operator()(_Tp(& __t)[_Size], _Up(& __u)[_Size]) const
+      noexcept(noexcept((*this)(*__t, *__u)))
+    {
+      // TODO(cjdb): replace with `ranges::swap_ranges`.
+      for (size_t __i = 0; __i < _Size; ++__i) {
+        (*this)(__t[__i], __u[__i]);
+      }
+    }
+
+    // 2.3   Otherwise, if `E1` and `E2` are lvalues of the same type `T` that models...
+    template<__exchangeable _Tp>
+    constexpr void operator()(_Tp& __x, _Tp& __y) const
+      noexcept(is_nothrow_move_constructible_v<_Tp> && is_nothrow_move_assignable_v<_Tp>)
+    {
+      __y = _VSTD::exchange(__x, _VSTD::move(__y));
+    }
+  };
+} // namespace ranges::__swap
+
+namespace ranges::inline __cpo {
+  inline constexpr auto swap = __swap::__fn{};
+} // namespace ranges::__cpo
+
+template<class _Tp>
+concept swappable = requires(_Tp& __a, _Tp& __b) { ranges::swap(__a, __b); };
+
+template<class _Tp, class _Up>
+concept swappable_with =
+  common_reference_with<_Tp, _Up> &&
+  requires(_Tp&& __t, _Up&& __u) {
+    ranges::swap(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Tp>(__t));
+    ranges::swap(_VSTD::forward<_Up>(__u), _VSTD::forward<_Up>(__u));
+    ranges::swap(_VSTD::forward<_Tp>(__t), _VSTD::forward<_Up>(__u));
+    ranges::swap(_VSTD::forward<_Up>(__u), _VSTD::forward<_Tp>(__t));
+  };
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_SWAPPABLE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__concepts/totally_ordered.h b/contrib/libs/cxxsupp/libcxx/include/__concepts/totally_ordered.h
new file mode 100644
index 00000000000..d8dd4a4944d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__concepts/totally_ordered.h
@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___CONCEPTS_TOTALLY_ORDERED_H
+#define _LIBCPP___CONCEPTS_TOTALLY_ORDERED_H
+
+#include <__concepts/boolean_testable.h>
+#include <__concepts/equality_comparable.h>
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [concept.totallyordered]
+
+template<class _Tp, class _Up>
+concept __partially_ordered_with =
+  requires(__make_const_lvalue_ref<_Tp> __t, __make_const_lvalue_ref<_Up> __u) {
+    { __t <  __u } -> __boolean_testable;
+    { __t >  __u } -> __boolean_testable;
+    { __t <= __u } -> __boolean_testable;
+    { __t >= __u } -> __boolean_testable;
+    { __u <  __t } -> __boolean_testable;
+    { __u >  __t } -> __boolean_testable;
+    { __u <= __t } -> __boolean_testable;
+    { __u >= __t } -> __boolean_testable;
+  };
+
+template<class _Tp>
+concept totally_ordered = equality_comparable<_Tp> && __partially_ordered_with<_Tp, _Tp>;
+
+template<class _Tp, class _Up>
+concept totally_ordered_with =
+  totally_ordered<_Tp> && totally_ordered<_Up> &&
+  equality_comparable_with<_Tp, _Up> &&
+  totally_ordered<
+    common_reference_t<
+      __make_const_lvalue_ref<_Tp>,
+      __make_const_lvalue_ref<_Up>>> &&
+  __partially_ordered_with<_Tp, _Up>;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CONCEPTS_TOTALLY_ORDERED_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__config b/contrib/libs/cxxsupp/libcxx/include/__config
new file mode 100644
index 00000000000..bdc54b92d1e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__config
@@ -0,0 +1,1428 @@
+// -*- C++ -*-
+//===--------------------------- __config ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CONFIG
+#define _LIBCPP_CONFIG
+#include <__wrappers_config>
+
+#if defined(_MSC_VER) && !defined(__clang__)
+#  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#    define _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
+#  endif
+#endif
+
+#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
+#pragma GCC system_header
+#endif
+
+// Move outside #ifdef __cplusplus because this needs to work in both C and C++ headers.
+#if defined(__apple_build_version__)
+#  define _LIBCPP_COMPILER_CLANG_BASED
+#  define _LIBCPP_APPLE_CLANG_VER (__apple_build_version__ / 10000)
+#elif defined(__clang__)
+#define _LIBCPP_COMPILER_CLANG
+#  define _LIBCPP_COMPILER_CLANG_BASED
+#  define _LIBCPP_CLANG_VER (__clang_major__ * 100 + __clang_minor__)
+#elif defined(__GNUC__)
+#define _LIBCPP_COMPILER_GCC
+#elif defined(_MSC_VER)
+#define _LIBCPP_COMPILER_MSVC
+
+#if _MSVC_LANG == 201705L
+#  define _LIBCPP_STD_VER 20
+#elif _MSVC_LANG == 201703L
+#  define _LIBCPP_STD_VER 17
+#else
+#  define _LIBCPP_STD_VER 14
+#endif
+
+#define _LIBCPP_UCRT_INCLUDE(x) <Y_UCRT_INCLUDE/x>
+#define _LIBCPP_MSVC_INCLUDE(x) <Y_MSVC_INCLUDE/x>
+#elif defined(__IBMCPP__)
+#define _LIBCPP_COMPILER_IBM
+#endif
+
+#ifdef __cplusplus
+
+#define _LIBCPP_VERSION 14000
+
+#ifndef _LIBCPP_ABI_VERSION
+#  define _LIBCPP_ABI_VERSION 1
+#endif
+
+#if __STDC_HOSTED__ == 0
+#  define _LIBCPP_FREESTANDING
+#endif
+
+#ifndef _LIBCPP_STD_VER
+#  if  __cplusplus <= 201103L
+#    define _LIBCPP_STD_VER 11
+#  elif __cplusplus <= 201402L
+#    define _LIBCPP_STD_VER 14
+#  elif __cplusplus <= 201703L
+#    define _LIBCPP_STD_VER 17
+#  elif __cplusplus <= 202002L
+#    define _LIBCPP_STD_VER 20
+#  else
+#    define _LIBCPP_STD_VER 21  // current year, or date of c++2b ratification
+#  endif
+#endif // _LIBCPP_STD_VER
+
+#if defined(__ELF__)
+#  define _LIBCPP_OBJECT_FORMAT_ELF   1
+#elif defined(__MACH__)
+#  define _LIBCPP_OBJECT_FORMAT_MACHO 1
+#elif defined(_WIN32) || defined(__CYGWIN__)
+#  define _LIBCPP_OBJECT_FORMAT_COFF  1
+#elif defined(__wasm__)
+#  define _LIBCPP_OBJECT_FORMAT_WASM  1
+#else
+   // ... add new file formats here ...
+#endif
+
+#if defined(_LIBCPP_ABI_UNSTABLE) || _LIBCPP_ABI_VERSION >= 2
+// Change short string representation so that string data starts at offset 0,
+// improving its alignment in some cases.
+#  define _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+// Fix deque iterator type in order to support incomplete types.
+#  define _LIBCPP_ABI_INCOMPLETE_TYPES_IN_DEQUE
+// Fix undefined behavior in how std::list stores its linked nodes.
+#  define _LIBCPP_ABI_LIST_REMOVE_NODE_POINTER_UB
+// Fix undefined behavior in  how __tree stores its end and parent nodes.
+#  define _LIBCPP_ABI_TREE_REMOVE_NODE_POINTER_UB
+// Fix undefined behavior in how __hash_table stores its pointer types.
+#  define _LIBCPP_ABI_FIX_UNORDERED_NODE_POINTER_UB
+#  define _LIBCPP_ABI_FORWARD_LIST_REMOVE_NODE_POINTER_UB
+#  define _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
+// Don't use a nullptr_t simulation type in C++03 instead using C++11 nullptr
+// provided under the alternate keyword __nullptr, which changes the mangling
+// of nullptr_t. This option is ABI incompatible with GCC in C++03 mode.
+#  define _LIBCPP_ABI_ALWAYS_USE_CXX11_NULLPTR
+// Define a key function for `bad_function_call` in the library, to centralize
+// its vtable and typeinfo to libc++ rather than having all other libraries
+// using that class define their own copies.
+#  define _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
+// Enable optimized version of __do_get_(un)signed which avoids redundant copies.
+#  define _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
+// In C++20 and later, don't derive std::plus from std::binary_function,
+// nor std::negate from std::unary_function.
+#  define _LIBCPP_ABI_NO_BINDER_BASES
+// Give reverse_iterator<T> one data member of type T, not two.
+// Also, in C++17 and later, don't derive iterator types from std::iterator.
+#  define _LIBCPP_ABI_NO_ITERATOR_BASES
+// Use the smallest possible integer type to represent the index of the variant.
+// Previously libc++ used "unsigned int" exclusively.
+#  define _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION
+// Unstable attempt to provide a more optimized std::function
+#  define _LIBCPP_ABI_OPTIMIZED_FUNCTION
+// All the regex constants must be distinct and nonzero.
+#  define _LIBCPP_ABI_REGEX_CONSTANTS_NONZERO
+// Use raw pointers, not wrapped ones, for std::span's iterator type.
+#  define _LIBCPP_ABI_SPAN_POINTER_ITERATORS
+// Re-worked external template instantiations for std::string with a focus on
+// performance and fast-path inlining.
+#  define _LIBCPP_ABI_STRING_OPTIMIZED_EXTERNAL_INSTANTIATION
+// Enable clang::trivial_abi on std::unique_ptr.
+#  define _LIBCPP_ABI_ENABLE_UNIQUE_PTR_TRIVIAL_ABI
+// Enable clang::trivial_abi on std::shared_ptr and std::weak_ptr
+#  define _LIBCPP_ABI_ENABLE_SHARED_PTR_TRIVIAL_ABI
+#elif _LIBCPP_ABI_VERSION == 1
+#  if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
+// Enable compiling copies of now inline methods into the dylib to support
+// applications compiled against older libraries. This is unnecessary with
+// COFF dllexport semantics, since dllexport forces a non-inline definition
+// of inline functions to be emitted anyway. Our own non-inline copy would
+// conflict with the dllexport-emitted copy, so we disable it.
+#    define _LIBCPP_DEPRECATED_ABI_LEGACY_LIBRARY_DEFINITIONS_FOR_INLINE_FUNCTIONS
+#  endif
+// Feature macros for disabling pre ABI v1 features. All of these options
+// are deprecated.
+#  if defined(__FreeBSD__)
+#    define _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
+#  endif
+#endif
+
+#if defined(_LIBCPP_BUILDING_LIBRARY) || defined(_LIBCPP_ABI_UNSTABLE) || _LIBCPP_ABI_VERSION >= 2
+// Enable additional explicit instantiations of iostreams components. This
+// reduces the number of weak definitions generated in programs that use
+// iostreams by providing a single strong definition in the shared library.
+# define _LIBCPP_ABI_ENABLE_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1
+#endif
+
+#define _LIBCPP_CONCAT1(_LIBCPP_X,_LIBCPP_Y) _LIBCPP_X##_LIBCPP_Y
+#define _LIBCPP_CONCAT(_LIBCPP_X,_LIBCPP_Y) _LIBCPP_CONCAT1(_LIBCPP_X,_LIBCPP_Y)
+
+#ifndef _LIBCPP_ABI_NAMESPACE
+# define _LIBCPP_ABI_NAMESPACE _LIBCPP_CONCAT(__y,_LIBCPP_ABI_VERSION)
+#endif
+
+#if __cplusplus < 201103L && !defined(_LIBCPP_COMPILER_MSVC)
+#define _LIBCPP_CXX03_LANG
+#endif
+
+#ifndef __has_attribute
+#define __has_attribute(__x) 0
+#endif
+
+#ifndef __has_builtin
+#define __has_builtin(__x) 0
+#endif
+
+#ifndef __has_extension
+#define __has_extension(__x) 0
+#endif
+
+#ifndef __has_feature
+#define __has_feature(__x) 0
+#endif
+
+#ifndef __has_cpp_attribute
+#define __has_cpp_attribute(__x) 0
+#endif
+
+// '__is_identifier' returns '0' if '__x' is a reserved identifier provided by
+// the compiler and '1' otherwise.
+#ifndef __is_identifier
+#define __is_identifier(__x) 1
+#endif
+
+#ifndef __has_declspec_attribute
+#define __has_declspec_attribute(__x) 0
+#endif
+
+#define __has_keyword(__x) !(__is_identifier(__x))
+
+#ifndef __has_include
+#define __has_include(...) 0
+#endif
+
+#if defined(_LIBCPP_COMPILER_GCC) && __cplusplus < 201103L
+#error "libc++ does not support using GCC with C++03. Please enable C++11"
+#endif
+
+// FIXME: ABI detection should be done via compiler builtin macros. This
+// is just a placeholder until Clang implements such macros. For now assume
+// that Windows compilers pretending to be MSVC++ target the Microsoft ABI,
+// and allow the user to explicitly specify the ABI to handle cases where this
+// heuristic falls short.
+#if defined(_LIBCPP_ABI_FORCE_ITANIUM) && defined(_LIBCPP_ABI_FORCE_MICROSOFT)
+#  error "Only one of _LIBCPP_ABI_FORCE_ITANIUM and _LIBCPP_ABI_FORCE_MICROSOFT can be defined"
+#elif defined(_LIBCPP_ABI_FORCE_ITANIUM)
+#  define _LIBCPP_ABI_ITANIUM
+#elif defined(_LIBCPP_ABI_FORCE_MICROSOFT)
+#  define _LIBCPP_ABI_MICROSOFT
+#else
+#  if defined(_WIN32) && defined(_MSC_VER)
+#    define _LIBCPP_ABI_MICROSOFT
+#  else
+#    define _LIBCPP_ABI_ITANIUM
+#  endif
+#endif
+
+#if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_NO_VCRUNTIME)
+# define _LIBCPP_ABI_VCRUNTIME
+#endif
+
+// Need to detect which libc we're using if we're on Linux.
+#if defined(__linux__)
+#  include <features.h>
+#  if defined(__GLIBC_PREREQ)
+#    define _LIBCPP_GLIBC_PREREQ(a, b) __GLIBC_PREREQ(a, b)
+#  else
+#    define _LIBCPP_GLIBC_PREREQ(a, b) 0
+#  endif // defined(__GLIBC_PREREQ)
+#endif // defined(__linux__)
+
+#ifdef __LITTLE_ENDIAN__
+#  if __LITTLE_ENDIAN__
+#    define _LIBCPP_LITTLE_ENDIAN
+#  endif  // __LITTLE_ENDIAN__
+#endif // __LITTLE_ENDIAN__
+
+#ifdef __BIG_ENDIAN__
+#  if __BIG_ENDIAN__
+#    define _LIBCPP_BIG_ENDIAN
+#  endif  // __BIG_ENDIAN__
+#endif // __BIG_ENDIAN__
+
+#ifdef __BYTE_ORDER__
+#  if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#    define _LIBCPP_LITTLE_ENDIAN
+#  elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#    define _LIBCPP_BIG_ENDIAN
+#  endif // __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#endif // __BYTE_ORDER__
+
+#ifdef __FreeBSD__
+#  include <sys/endian.h>
+#  include <osreldate.h>
+#  if _BYTE_ORDER == _LITTLE_ENDIAN
+#    define _LIBCPP_LITTLE_ENDIAN
+#  else  // _BYTE_ORDER == _LITTLE_ENDIAN
+#    define _LIBCPP_BIG_ENDIAN
+#  endif  // _BYTE_ORDER == _LITTLE_ENDIAN
+#endif // __FreeBSD__
+
+#if defined(__NetBSD__) || defined(__OpenBSD__)
+#  include <sys/endian.h>
+#  if _BYTE_ORDER == _LITTLE_ENDIAN
+#    define _LIBCPP_LITTLE_ENDIAN
+#  else  // _BYTE_ORDER == _LITTLE_ENDIAN
+#    define _LIBCPP_BIG_ENDIAN
+#  endif  // _BYTE_ORDER == _LITTLE_ENDIAN
+#endif // defined(__NetBSD__) || defined(__OpenBSD__)
+
+#if defined(_WIN32)
+#  define _LIBCPP_WIN32API
+#  define _LIBCPP_LITTLE_ENDIAN
+#  define _LIBCPP_SHORT_WCHAR   1
+// Both MinGW and native MSVC provide a "MSVC"-like environment
+#  define _LIBCPP_MSVCRT_LIKE
+// If mingw not explicitly detected, assume using MS C runtime only if
+// a MS compatibility version is specified.
+#  if defined(_MSC_VER) && !defined(__MINGW32__)
+#    define _LIBCPP_MSVCRT // Using Microsoft's C Runtime library
+#  endif
+#  if (defined(_M_AMD64) || defined(__x86_64__)) || (defined(_M_ARM) || defined(__arm__))
+#    define _LIBCPP_HAS_BITSCAN64
+#  endif
+#  define _LIBCPP_HAS_OPEN_WITH_WCHAR
+#  if defined(_LIBCPP_MSVCRT)
+#    define _LIBCPP_HAS_QUICK_EXIT
+#  endif
+
+// Some CRT APIs are unavailable to store apps
+#  if defined(WINAPI_FAMILY)
+#    include <winapifamily.h>
+#    if !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP) &&                  \
+        (!defined(WINAPI_PARTITION_SYSTEM) ||                                  \
+         !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_SYSTEM))
+#      define _LIBCPP_WINDOWS_STORE_APP
+#    endif
+#  endif
+#endif // defined(_WIN32)
+
+#ifdef __sun__
+#  include <sys/isa_defs.h>
+#  ifdef _LITTLE_ENDIAN
+#    define _LIBCPP_LITTLE_ENDIAN
+#  else
+#    define _LIBCPP_BIG_ENDIAN
+#  endif
+#endif // __sun__
+
+#if defined(_AIX) && !defined(__64BIT__)
+   // The size of wchar is 2 byte on 32-bit mode on AIX.
+#  define _LIBCPP_SHORT_WCHAR   1
+#endif
+
+#if defined(__OpenBSD__)
+   // Certain architectures provide arc4random(). Prefer using
+   // arc4random() over /dev/{u,}random to make it possible to obtain
+   // random data even when using sandboxing mechanisms such as chroots,
+   // Capsicum, etc.
+#  define _LIBCPP_USING_ARC4_RANDOM
+#elif defined(__Fuchsia__) || defined(__wasi__)
+#  define _LIBCPP_USING_GETENTROPY
+#elif defined(__native_client__)
+   // NaCl's sandbox (which PNaCl also runs in) doesn't allow filesystem access,
+   // including accesses to the special files under /dev. C++11's
+   // std::random_device is instead exposed through a NaCl syscall.
+#  define _LIBCPP_USING_NACL_RANDOM
+#elif defined(_LIBCPP_WIN32API)
+#  define _LIBCPP_USING_WIN32_RANDOM
+#else
+#  define _LIBCPP_USING_DEV_RANDOM
+#endif
+
+#if !defined(_LIBCPP_LITTLE_ENDIAN) && !defined(_LIBCPP_BIG_ENDIAN)
+#  include <endian.h>
+#  if __BYTE_ORDER == __LITTLE_ENDIAN
+#    define _LIBCPP_LITTLE_ENDIAN
+#  elif __BYTE_ORDER == __BIG_ENDIAN
+#    define _LIBCPP_BIG_ENDIAN
+#  else  // __BYTE_ORDER == __BIG_ENDIAN
+#    error unable to determine endian
+#  endif
+#endif // !defined(_LIBCPP_LITTLE_ENDIAN) && !defined(_LIBCPP_BIG_ENDIAN)
+
+#if __has_attribute(__no_sanitize__) && !defined(_LIBCPP_COMPILER_GCC)
+#  define _LIBCPP_NO_CFI __attribute__((__no_sanitize__("cfi")))
+#else
+#  define _LIBCPP_NO_CFI
+#endif
+
+// If the compiler supports using_if_exists, pretend we have those functions and they'll
+// be picked up if the C library provides them.
+//
+// TODO: Once we drop support for Clang 12, we can assume the compiler supports using_if_exists
+//       for platforms that don't have a conforming C11 library, so we can drop this whole thing.
+#if __has_attribute(using_if_exists)
+# define _LIBCPP_HAS_TIMESPEC_GET
+# define _LIBCPP_HAS_QUICK_EXIT
+# define _LIBCPP_HAS_ALIGNED_ALLOC
+#else
+#if (defined(__ISO_C_VISIBLE) && (__ISO_C_VISIBLE >= 2011)) || __cplusplus >= 201103L
+#  if defined(__FreeBSD__)
+#    define _LIBCPP_HAS_ALIGNED_ALLOC
+#    define _LIBCPP_HAS_QUICK_EXIT
+#    if __FreeBSD_version >= 1300064 || \
+       (__FreeBSD_version >= 1201504 && __FreeBSD_version < 1300000)
+#      define _LIBCPP_HAS_TIMESPEC_GET
+#    endif
+#  elif defined(__BIONIC__)
+#    if __ANDROID_API__ >= 21
+#      define _LIBCPP_HAS_QUICK_EXIT
+#    endif
+#    if __ANDROID_API__ >= 28
+#      define _LIBCPP_HAS_ALIGNED_ALLOC
+#    endif
+#    if __ANDROID_API__ >= 29
+#      define _LIBCPP_HAS_TIMESPEC_GET
+#    endif
+#  elif defined(__Fuchsia__) || defined(__wasi__) || defined(__NetBSD__)
+#    define _LIBCPP_HAS_ALIGNED_ALLOC
+#    define _LIBCPP_HAS_QUICK_EXIT
+#    define _LIBCPP_HAS_TIMESPEC_GET
+#  elif defined(__OpenBSD__)
+#    define _LIBCPP_HAS_ALIGNED_ALLOC
+#    define _LIBCPP_HAS_TIMESPEC_GET
+#  elif defined(__linux__)
+#    if !defined(_LIBCPP_HAS_MUSL_LIBC)
+#      if _LIBCPP_GLIBC_PREREQ(2, 15) || defined(__BIONIC__)
+#        define _LIBCPP_HAS_QUICK_EXIT
+#      endif
+#      if _LIBCPP_GLIBC_PREREQ(2, 17)
+#        define _LIBCPP_HAS_ALIGNED_ALLOC
+#        define _LIBCPP_HAS_TIMESPEC_GET
+#      endif
+#    else // defined(_LIBCPP_HAS_MUSL_LIBC)
+#      define _LIBCPP_HAS_ALIGNED_ALLOC
+#      define _LIBCPP_HAS_QUICK_EXIT
+#      define _LIBCPP_HAS_TIMESPEC_GET
+#    endif
+#  elif defined(_LIBCPP_MSVCRT)
+     // Using Microsoft's C Runtime library, not MinGW
+#    define _LIBCPP_HAS_TIMESPEC_GET
+#  elif defined(__APPLE__)
+     // timespec_get and aligned_alloc were introduced in macOS 10.15 and
+     // aligned releases
+#    if ((defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 101500) || \
+         (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ >= 130000) || \
+         (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ >= 130000) || \
+         (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ >= 60000))
+#      define _LIBCPP_HAS_ALIGNED_ALLOC
+#      define _LIBCPP_HAS_TIMESPEC_GET
+#    endif
+#  endif // __APPLE__
+#endif
+#endif // __has_attribute(using_if_exists)
+
+#ifndef _LIBCPP_CXX03_LANG
+# define _LIBCPP_ALIGNOF(_Tp) alignof(_Tp)
+#elif defined(_LIBCPP_COMPILER_CLANG_BASED)
+# define _LIBCPP_ALIGNOF(_Tp) _Alignof(_Tp)
+#else
+# error "We don't know a correct way to implement alignof(T) in C++03 outside of Clang"
+#endif
+
+#define _LIBCPP_PREFERRED_ALIGNOF(_Tp) __alignof(_Tp)
+
+#if defined(_LIBCPP_COMPILER_CLANG_BASED)
+
+#if defined(_LIBCPP_ALTERNATE_STRING_LAYOUT)
+#  error _LIBCPP_ALTERNATE_STRING_LAYOUT is deprecated, please use _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT instead
+#endif
+#if defined(__APPLE__) && !defined(__i386__) && !defined(__x86_64__) &&       \
+    (!defined(__arm__) || __ARM_ARCH_7K__ >= 2)
+#  define _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+#endif
+
+#if __has_feature(cxx_alignas)
+#  define _ALIGNAS_TYPE(x) alignas(x)
+#  define _ALIGNAS(x) alignas(x)
+#else
+#  define _ALIGNAS_TYPE(x) __attribute__((__aligned__(_LIBCPP_ALIGNOF(x))))
+#  define _ALIGNAS(x) __attribute__((__aligned__(x)))
+#endif
+
+#if __cplusplus < 201103L
+typedef __char16_t char16_t;
+typedef __char32_t char32_t;
+#endif
+
+#if !__has_feature(cxx_exceptions)
+#  define _LIBCPP_NO_EXCEPTIONS
+#endif
+
+#if !(__has_feature(cxx_strong_enums))
+#define _LIBCPP_HAS_NO_STRONG_ENUMS
+#endif
+
+#if __has_feature(cxx_attributes)
+#  define _LIBCPP_NORETURN [[noreturn]]
+#else
+#  define _LIBCPP_NORETURN __attribute__ ((noreturn))
+#endif
+
+#if !(__has_feature(cxx_nullptr))
+#  if (__has_extension(cxx_nullptr) || __has_keyword(__nullptr)) && defined(_LIBCPP_ABI_ALWAYS_USE_CXX11_NULLPTR)
+#    define nullptr __nullptr
+#  else
+#    define _LIBCPP_HAS_NO_NULLPTR
+#  endif
+#endif
+
+// Objective-C++ features (opt-in)
+#if __has_feature(objc_arc)
+#define _LIBCPP_HAS_OBJC_ARC
+#endif
+
+#if __has_feature(objc_arc_weak)
+#define _LIBCPP_HAS_OBJC_ARC_WEAK
+#endif
+
+#if __has_extension(blocks)
+#  define _LIBCPP_HAS_EXTENSION_BLOCKS
+#endif
+
+#if defined(_LIBCPP_HAS_EXTENSION_BLOCKS) && defined(__APPLE__)
+#  define _LIBCPP_HAS_BLOCKS_RUNTIME
+#endif
+
+#if !(__has_feature(cxx_noexcept))
+#define _LIBCPP_HAS_NO_NOEXCEPT
+#endif
+
+#if !__has_feature(address_sanitizer)
+#define _LIBCPP_HAS_NO_ASAN
+#endif
+
+// Allow for build-time disabling of unsigned integer sanitization
+#if __has_attribute(no_sanitize)
+#define _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK __attribute__((__no_sanitize__("unsigned-integer-overflow")))
+#endif
+
+#define _LIBCPP_ALWAYS_INLINE __attribute__ ((__always_inline__))
+
+#define _LIBCPP_DISABLE_EXTENSION_WARNING __extension__
+
+#elif defined(_LIBCPP_COMPILER_GCC)
+
+#define _ALIGNAS(x) __attribute__((__aligned__(x)))
+#define _ALIGNAS_TYPE(x) __attribute__((__aligned__(_LIBCPP_ALIGNOF(x))))
+
+#define _LIBCPP_NORETURN __attribute__((noreturn))
+
+#if !defined(__EXCEPTIONS)
+#  define _LIBCPP_NO_EXCEPTIONS
+#endif
+
+#if !defined(__SANITIZE_ADDRESS__)
+#define _LIBCPP_HAS_NO_ASAN
+#endif
+
+#define _LIBCPP_ALWAYS_INLINE __attribute__ ((__always_inline__))
+
+#define _LIBCPP_DISABLE_EXTENSION_WARNING __extension__
+
+#elif defined(_LIBCPP_COMPILER_MSVC)
+
+#define _LIBCPP_TOSTRING2(x) #x
+#define _LIBCPP_TOSTRING(x) _LIBCPP_TOSTRING2(x)
+#define _LIBCPP_WARNING(x) __pragma(message(__FILE__ "(" _LIBCPP_TOSTRING(__LINE__) ") : warning note: " x))
+
+#if _MSC_VER < 1900
+#error "MSVC versions prior to Visual Studio 2015 are not supported"
+#endif
+
+#define _LIBCPP_HAS_IS_FINAL
+#define __alignof__ __alignof
+#define _LIBCPP_NORETURN __declspec(noreturn)
+#define _ALIGNAS(x) __declspec(align(x))
+#define _ALIGNAS_TYPE(x) alignas(x)
+
+#define _LIBCPP_UNDERLYING_TYPE(T) __underlying_type(T)
+#define _LIBCPP_IS_LITERAL(T) __is_literal_type(T)
+#undef __has_feature
+#define __has_feature(x) __has_feature_##x
+#define __has_feature_is_standard_layout 1
+#define __has_feature_is_trivially_copyable 1
+#define __has_feature_is_trivial 1
+#define __has_feature_is_pod 1
+#define __has_feature_cxx_noexcept 1
+#define __has_feature_has_nothrow_assign 1
+#define __has_feature_is_union 1
+#define __has_feature_is_class 1
+#define __has_feature_is_enum 1
+#define __has_feature_is_convertible_to 1
+#define __has_feature_is_empty 1
+#define __has_feature_is_polymorphic 1
+#define __has_feature_has_virtual_destructor 1
+#define __has_feature_cxx_reference_qualified_functions 1
+#define __has_feature_is_constructible 1
+#define __has_feature_is_trivially_constructible 1
+#define __has_feature_is_trivially_assignable 1
+#define __has_feature_is_convertible_to 1
+#define __has_feature_has_trivial_constructor 1
+#define __has_feature_has_trivial_destructor 1
+#define __has_feature_has_nothrow_constructor 1
+#define __has_feature_has_nothrow_copy 1
+#define __has_feature_cxx_explicit_conversions 1
+
+#undef __has_builtin
+#define __has_builtin(x) __has_builtin_##x
+#define __has_builtin___builtin_addressof 1
+
+#define _LIBCPP_WEAK
+
+#define _LIBCPP_HAS_NO_ASAN
+
+#define _LIBCPP_ALWAYS_INLINE __forceinline
+
+#define _LIBCPP_HAS_NO_VECTOR_EXTENSION
+
+#define _LIBCPP_DISABLE_EXTENSION_WARNING
+
+#elif defined(_LIBCPP_COMPILER_IBM)
+
+#define _ALIGNAS(x) __attribute__((__aligned__(x)))
+#define _ALIGNAS_TYPE(x) __attribute__((__aligned__(_LIBCPP_ALIGNOF(x))))
+#define _ATTRIBUTE(x) __attribute__((x))
+#define _LIBCPP_NORETURN __attribute__((noreturn))
+
+#define _LIBCPP_HAS_NO_UNICODE_CHARS
+
+#if defined(_AIX)
+#define __MULTILOCALE_API
+#endif
+
+#define _LIBCPP_HAS_NO_ASAN
+
+#define _LIBCPP_ALWAYS_INLINE __attribute__ ((__always_inline__))
+
+#define _LIBCPP_HAS_NO_VECTOR_EXTENSION
+
+#define _LIBCPP_DISABLE_EXTENSION_WARNING
+
+#endif // _LIBCPP_COMPILER_[CLANG|GCC|MSVC|IBM]
+
+#if defined(_LIBCPP_OBJECT_FORMAT_COFF)
+
+#ifdef _DLL
+#  define _LIBCPP_CRT_FUNC __declspec(dllimport)
+#else
+#  define _LIBCPP_CRT_FUNC
+#endif
+
+#if defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+#  define _LIBCPP_DLL_VIS
+#  define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
+#  define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
+#  define _LIBCPP_OVERRIDABLE_FUNC_VIS
+#  define _LIBCPP_EXPORTED_FROM_ABI
+#elif defined(_LIBCPP_BUILDING_LIBRARY)
+#  define _LIBCPP_DLL_VIS __declspec(dllexport)
+#  if defined(__MINGW32__)
+#    define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS _LIBCPP_DLL_VIS
+#    define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
+#  else
+#    define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
+#    define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS _LIBCPP_DLL_VIS
+#  endif
+#  define _LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_DLL_VIS
+#  define _LIBCPP_EXPORTED_FROM_ABI __declspec(dllexport)
+#else
+#  define _LIBCPP_DLL_VIS __declspec(dllimport)
+#  define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS _LIBCPP_DLL_VIS
+#  define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
+#  define _LIBCPP_OVERRIDABLE_FUNC_VIS
+#  define _LIBCPP_EXPORTED_FROM_ABI __declspec(dllimport)
+#endif
+
+#define _LIBCPP_TYPE_VIS            _LIBCPP_DLL_VIS
+#define _LIBCPP_FUNC_VIS            _LIBCPP_DLL_VIS
+#define _LIBCPP_EXCEPTION_ABI       _LIBCPP_DLL_VIS
+#define _LIBCPP_HIDDEN
+#define _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+#define _LIBCPP_TEMPLATE_VIS
+#define _LIBCPP_TEMPLATE_DATA_VIS
+#define _LIBCPP_ENUM_VIS
+
+#endif // defined(_LIBCPP_OBJECT_FORMAT_COFF)
+
+#ifndef _LIBCPP_HIDDEN
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+#    define _LIBCPP_HIDDEN __attribute__ ((__visibility__("hidden")))
+#  else
+#    define _LIBCPP_HIDDEN
+#  endif
+#endif
+
+#ifndef _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+// The inline should be removed once PR32114 is resolved
+#    define _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS inline _LIBCPP_HIDDEN
+#  else
+#    define _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+#  endif
+#endif
+
+#ifndef _LIBCPP_FUNC_VIS
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+#    define _LIBCPP_FUNC_VIS __attribute__ ((__visibility__("default")))
+#  else
+#    define _LIBCPP_FUNC_VIS
+#  endif
+#endif
+
+#ifndef _LIBCPP_TYPE_VIS
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+#    define _LIBCPP_TYPE_VIS __attribute__ ((__visibility__("default")))
+#  else
+#    define _LIBCPP_TYPE_VIS
+#  endif
+#endif
+
+#ifndef _LIBCPP_TEMPLATE_VIS
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+#    if __has_attribute(__type_visibility__)
+#      define _LIBCPP_TEMPLATE_VIS __attribute__ ((__type_visibility__("default")))
+#    else
+#      define _LIBCPP_TEMPLATE_VIS __attribute__ ((__visibility__("default")))
+#    endif
+#  else
+#    define _LIBCPP_TEMPLATE_VIS
+#  endif
+#endif
+
+#ifndef _LIBCPP_TEMPLATE_DATA_VIS
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+#    define _LIBCPP_TEMPLATE_DATA_VIS __attribute__ ((__visibility__("default")))
+#  else
+#    define _LIBCPP_TEMPLATE_DATA_VIS
+#  endif
+#endif
+
+#ifndef _LIBCPP_EXPORTED_FROM_ABI
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+#    define _LIBCPP_EXPORTED_FROM_ABI __attribute__((__visibility__("default")))
+#  else
+#    define _LIBCPP_EXPORTED_FROM_ABI
+#  endif
+#endif
+
+#ifndef _LIBCPP_OVERRIDABLE_FUNC_VIS
+#define _LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_FUNC_VIS
+#endif
+
+#ifndef _LIBCPP_EXCEPTION_ABI
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+#    define _LIBCPP_EXCEPTION_ABI __attribute__ ((__visibility__("default")))
+#  else
+#    define _LIBCPP_EXCEPTION_ABI
+#  endif
+#endif
+
+#ifndef _LIBCPP_ENUM_VIS
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS) && __has_attribute(__type_visibility__)
+#    define _LIBCPP_ENUM_VIS __attribute__ ((__type_visibility__("default")))
+#  else
+#    define _LIBCPP_ENUM_VIS
+#  endif
+#endif
+
+#ifndef _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+#    define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __attribute__ ((__visibility__("default")))
+#  else
+#    define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
+#  endif
+#endif
+
+#ifndef _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
+#define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
+#endif
+
+#if __has_attribute(internal_linkage)
+#  define _LIBCPP_INTERNAL_LINKAGE __attribute__ ((internal_linkage))
+#else
+#  define _LIBCPP_INTERNAL_LINKAGE _LIBCPP_ALWAYS_INLINE
+#endif
+
+#if __has_attribute(exclude_from_explicit_instantiation)
+#  define _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION __attribute__ ((__exclude_from_explicit_instantiation__))
+#else
+   // Try to approximate the effect of exclude_from_explicit_instantiation
+   // (which is that entities are not assumed to be provided by explicit
+   // template instantiations in the dylib) by always inlining those entities.
+#ifdef _LIBCPP_COMPILER_MSVC
+#  define _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION
+#else
+#  define _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION _LIBCPP_ALWAYS_INLINE
+#endif
+#endif
+
+#ifndef _LIBCPP_HIDE_FROM_ABI_PER_TU
+#  ifndef _LIBCPP_HIDE_FROM_ABI_PER_TU_BY_DEFAULT
+#    define _LIBCPP_HIDE_FROM_ABI_PER_TU 0
+#  else
+#    define _LIBCPP_HIDE_FROM_ABI_PER_TU 1
+#  endif
+#endif
+
+#ifndef _LIBCPP_HIDE_FROM_ABI
+#  if _LIBCPP_HIDE_FROM_ABI_PER_TU
+#    define _LIBCPP_HIDE_FROM_ABI _LIBCPP_HIDDEN _LIBCPP_INTERNAL_LINKAGE
+#  else
+#    define _LIBCPP_HIDE_FROM_ABI _LIBCPP_HIDDEN _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION
+#  endif
+#endif
+
+#ifdef _LIBCPP_BUILDING_LIBRARY
+#  if _LIBCPP_ABI_VERSION > 1
+#    define _LIBCPP_HIDE_FROM_ABI_AFTER_V1 _LIBCPP_HIDE_FROM_ABI
+#  else
+#    define _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+#  endif
+#else
+#  define _LIBCPP_HIDE_FROM_ABI_AFTER_V1 _LIBCPP_HIDE_FROM_ABI
+#endif
+
+// Just so we can migrate to the new macros gradually.
+#define _LIBCPP_INLINE_VISIBILITY _LIBCPP_HIDE_FROM_ABI
+
+// Inline namespaces are available in Clang/GCC/MSVC regardless of C++ dialect.
+#define _LIBCPP_BEGIN_NAMESPACE_STD namespace std { inline namespace _LIBCPP_ABI_NAMESPACE {
+#define _LIBCPP_END_NAMESPACE_STD  } }
+#define _VSTD std::_LIBCPP_ABI_NAMESPACE
+_LIBCPP_BEGIN_NAMESPACE_STD _LIBCPP_END_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 17
+#define _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM \
+  _LIBCPP_BEGIN_NAMESPACE_STD inline namespace __fs { namespace filesystem {
+#else
+#define _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM \
+  _LIBCPP_BEGIN_NAMESPACE_STD namespace __fs { namespace filesystem {
+#endif
+
+#define _LIBCPP_END_NAMESPACE_FILESYSTEM \
+  _LIBCPP_END_NAMESPACE_STD } }
+
+#define _VSTD_FS _VSTD::__fs::filesystem
+
+#if __has_attribute(__enable_if__)
+#   define _LIBCPP_PREFERRED_OVERLOAD __attribute__ ((__enable_if__(true, "")))
+#endif
+
+#ifndef _LIBCPP_HAS_NO_NOEXCEPT
+#  define _NOEXCEPT noexcept
+#  define _NOEXCEPT_(x) noexcept(x)
+#else
+#  define _NOEXCEPT throw()
+#  define _NOEXCEPT_(x)
+#endif
+
+#ifdef _LIBCPP_HAS_NO_UNICODE_CHARS
+typedef unsigned short char16_t;
+typedef unsigned int   char32_t;
+#endif
+
+#ifndef __SIZEOF_INT128__
+#define _LIBCPP_HAS_NO_INT128
+#endif
+
+#ifdef _LIBCPP_CXX03_LANG
+# define static_assert(...) _Static_assert(__VA_ARGS__)
+# define decltype(...) __decltype(__VA_ARGS__)
+#endif // _LIBCPP_CXX03_LANG
+
+#ifdef _LIBCPP_CXX03_LANG
+#  define _LIBCPP_CONSTEXPR
+#else
+#  define _LIBCPP_CONSTEXPR constexpr
+#endif
+
+#ifndef __cpp_consteval
+#  define _LIBCPP_CONSTEVAL _LIBCPP_CONSTEXPR
+#else
+#  define _LIBCPP_CONSTEVAL consteval
+#endif
+
+#if !defined(__cpp_concepts) || __cpp_concepts < 201907L
+#define _LIBCPP_HAS_NO_CONCEPTS
+#endif
+
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_HAS_NO_CONCEPTS)
+#define _LIBCPP_HAS_NO_RANGES
+#endif
+
+#ifdef _LIBCPP_CXX03_LANG
+#  define _LIBCPP_DEFAULT {}
+#else
+#  define _LIBCPP_DEFAULT = default;
+#endif
+
+#ifdef __GNUC__
+#  define _LIBCPP_NOALIAS __attribute__((__malloc__))
+#else
+#  define _LIBCPP_NOALIAS
+#endif
+
+#if __has_attribute(using_if_exists)
+# define _LIBCPP_USING_IF_EXISTS __attribute__((using_if_exists))
+#else
+# define _LIBCPP_USING_IF_EXISTS
+#endif
+
+#ifdef _LIBCPP_HAS_NO_STRONG_ENUMS
+#  define _LIBCPP_DECLARE_STRONG_ENUM(x) struct _LIBCPP_TYPE_VIS x { enum __lx
+#  define _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(x) \
+     __lx __v_; \
+     _LIBCPP_INLINE_VISIBILITY x(__lx __v) : __v_(__v) {} \
+     _LIBCPP_INLINE_VISIBILITY explicit x(int __v) : __v_(static_cast<__lx>(__v)) {} \
+     _LIBCPP_INLINE_VISIBILITY operator int() const {return __v_;} \
+     };
+#else  // _LIBCPP_HAS_NO_STRONG_ENUMS
+#  define _LIBCPP_DECLARE_STRONG_ENUM(x) enum class _LIBCPP_ENUM_VIS x
+#  define _LIBCPP_DECLARE_STRONG_ENUM_EPILOG(x)
+#endif // _LIBCPP_HAS_NO_STRONG_ENUMS
+
+// _LIBCPP_DEBUG potential values:
+//  - undefined: No assertions. This is the default.
+//  - 0:         Basic assertions
+//  - 1:         Basic assertions + iterator validity checks.
+#if !defined(_LIBCPP_DEBUG)
+# define _LIBCPP_DEBUG_LEVEL 0
+#elif _LIBCPP_DEBUG == 0
+# define _LIBCPP_DEBUG_LEVEL 1
+#elif _LIBCPP_DEBUG == 1
+# define _LIBCPP_DEBUG_LEVEL 2
+#else
+# error Supported values for _LIBCPP_DEBUG are 0 and 1
+#endif
+
+// Libc++ allows disabling extern template instantiation declarations by
+// means of users defining _LIBCPP_DISABLE_EXTERN_TEMPLATE.
+//
+// Furthermore, when the Debug mode is enabled, we disable extern declarations
+// when building user code because we don't want to use the functions compiled
+// in the library, which might not have had the debug mode enabled when built.
+// However, some extern declarations need to be used, because code correctness
+// depends on it (several instances in <locale>). Those special declarations
+// are declared with _LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE, which is enabled
+// even when the debug mode is enabled.
+#if defined(_LIBCPP_DISABLE_EXTERN_TEMPLATE)
+#   define _LIBCPP_EXTERN_TEMPLATE(...) /* nothing */
+#   define _LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(...) /* nothing */
+#elif _LIBCPP_DEBUG_LEVEL >= 1 && !defined(_LIBCPP_BUILDING_LIBRARY)
+#   define _LIBCPP_EXTERN_TEMPLATE(...) /* nothing */
+#   define _LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(...) extern template __VA_ARGS__;
+#else
+#   define _LIBCPP_EXTERN_TEMPLATE(...) extern template __VA_ARGS__;
+#   define _LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(...) extern template __VA_ARGS__;
+#endif
+
+#if defined(__APPLE__) || defined(__FreeBSD__) || defined(_LIBCPP_MSVCRT_LIKE) || \
+    defined(__sun__) || defined(__NetBSD__)
+#define _LIBCPP_LOCALE__L_EXTENSIONS 1
+#endif
+
+#ifdef __FreeBSD__
+#define _DECLARE_C99_LDBL_MATH 1
+#endif
+
+// If we are getting operator new from the MSVC CRT, then allocation overloads
+// for align_val_t were added in 19.12, aka VS 2017 version 15.3.
+#if defined(_LIBCPP_MSVCRT) && defined(_MSC_VER) && _MSC_VER < 1912
+#  define _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
+#elif defined(_LIBCPP_ABI_VCRUNTIME) && !defined(__cpp_aligned_new)
+   // We're deferring to Microsoft's STL to provide aligned new et al. We don't
+   // have it unless the language feature test macro is defined.
+#  define _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
+#elif defined(__MVS__)
+#  define _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
+#endif
+
+#if defined(_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION) || \
+    (!defined(__cpp_aligned_new) || __cpp_aligned_new < 201606)
+#  define _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
+#endif
+
+#if defined(__APPLE__) || defined(__FreeBSD__)
+#define _LIBCPP_HAS_DEFAULTRUNELOCALE
+#endif
+
+#if defined(__APPLE__) || defined(__FreeBSD__) || defined(__sun__)
+#define _LIBCPP_WCTYPE_IS_MASK
+#endif
+
+#if _LIBCPP_STD_VER <= 17 || !defined(__cpp_char8_t)
+#define _LIBCPP_HAS_NO_CHAR8_T
+#endif
+
+// Deprecation macros.
+//
+// Deprecations warnings are always enabled, except when users explicitly opt-out
+// by defining _LIBCPP_DISABLE_DEPRECATION_WARNINGS.
+#if !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS)
+#  if __has_attribute(deprecated)
+#    define _LIBCPP_DEPRECATED __attribute__ ((deprecated))
+#  elif _LIBCPP_STD_VER > 11
+#    define _LIBCPP_DEPRECATED [[deprecated]]
+#  else
+#    define _LIBCPP_DEPRECATED
+#  endif
+#else
+#  define _LIBCPP_DEPRECATED
+#endif
+
+#if !defined(_LIBCPP_CXX03_LANG)
+#  define _LIBCPP_DEPRECATED_IN_CXX11 _LIBCPP_DEPRECATED
+#else
+#  define _LIBCPP_DEPRECATED_IN_CXX11
+#endif
+
+#if _LIBCPP_STD_VER >= 14
+#  define _LIBCPP_DEPRECATED_IN_CXX14 _LIBCPP_DEPRECATED
+#else
+#  define _LIBCPP_DEPRECATED_IN_CXX14
+#endif
+
+#if _LIBCPP_STD_VER >= 17
+#  define _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_DEPRECATED
+#else
+#  define _LIBCPP_DEPRECATED_IN_CXX17
+#endif
+
+#if _LIBCPP_STD_VER > 17
+#  define _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_DEPRECATED
+#else
+#  define _LIBCPP_DEPRECATED_IN_CXX20
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_CHAR8_T)
+#  define _LIBCPP_DEPRECATED_WITH_CHAR8_T _LIBCPP_DEPRECATED
+#else
+#  define _LIBCPP_DEPRECATED_WITH_CHAR8_T
+#endif
+
+#if defined(_LIBCPP_COMPILER_CLANG_BASED) || defined(_LIBCPP_COMPILER_GCC)
+#   define _LIBCPP_SUPPRESS_DEPRECATED_PUSH \
+        _Pragma("GCC diagnostic push") \
+        _Pragma("GCC diagnostic ignored \"-Wdeprecated\"") \
+        _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
+#   define _LIBCPP_SUPPRESS_DEPRECATED_POP \
+        _Pragma("GCC diagnostic pop")
+#else
+#   define _LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#   define _LIBCPP_SUPPRESS_DEPRECATED_POP
+#endif
+
+#if _LIBCPP_STD_VER <= 11
+#  define _LIBCPP_EXPLICIT_AFTER_CXX11
+#else
+#  define _LIBCPP_EXPLICIT_AFTER_CXX11 explicit
+#endif
+
+#if _LIBCPP_STD_VER > 11
+#  define _LIBCPP_CONSTEXPR_AFTER_CXX11 constexpr
+#else
+#  define _LIBCPP_CONSTEXPR_AFTER_CXX11
+#endif
+
+#if _LIBCPP_STD_VER > 14
+#  define _LIBCPP_CONSTEXPR_AFTER_CXX14 constexpr
+#else
+#  define _LIBCPP_CONSTEXPR_AFTER_CXX14
+#endif
+
+#if _LIBCPP_STD_VER > 17
+#  define _LIBCPP_CONSTEXPR_AFTER_CXX17 constexpr
+#else
+#  define _LIBCPP_CONSTEXPR_AFTER_CXX17
+#endif
+
+#if __has_cpp_attribute(nodiscard) || defined(_LIBCPP_COMPILER_MSVC)
+#  define _LIBCPP_NODISCARD [[nodiscard]]
+#elif defined(_LIBCPP_COMPILER_CLANG_BASED) && !defined(_LIBCPP_CXX03_LANG)
+#  define _LIBCPP_NODISCARD [[clang::warn_unused_result]]
+#else
+// We can't use GCC's [[gnu::warn_unused_result]] and
+// __attribute__((warn_unused_result)), because GCC does not silence them via
+// (void) cast.
+#  define _LIBCPP_NODISCARD
+#endif
+
+// _LIBCPP_NODISCARD_EXT may be used to apply [[nodiscard]] to entities not
+// specified as such as an extension.
+#if defined(_LIBCPP_ENABLE_NODISCARD) && !defined(_LIBCPP_DISABLE_NODISCARD_EXT)
+#  define _LIBCPP_NODISCARD_EXT _LIBCPP_NODISCARD
+#else
+#  define _LIBCPP_NODISCARD_EXT
+#endif
+
+#if !defined(_LIBCPP_DISABLE_NODISCARD_AFTER_CXX17) && \
+    (_LIBCPP_STD_VER > 17 || defined(_LIBCPP_ENABLE_NODISCARD))
+#  define _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_NODISCARD
+#else
+#  define _LIBCPP_NODISCARD_AFTER_CXX17
+#endif
+
+#if !defined(_LIBCPP_DEBUG) && _LIBCPP_STD_VER > 11
+#   define _LIBCPP_CONSTEXPR_IF_NODEBUG constexpr
+#else
+#   define _LIBCPP_CONSTEXPR_IF_NODEBUG
+#endif
+
+#if __has_attribute(no_destroy)
+#  define _LIBCPP_NO_DESTROY __attribute__((__no_destroy__))
+#else
+#  define _LIBCPP_NO_DESTROY
+#endif
+
+#ifndef _LIBCPP_HAS_NO_ASAN
+extern "C" _LIBCPP_FUNC_VIS void __sanitizer_annotate_contiguous_container(
+  const void *, const void *, const void *, const void *);
+#endif
+
+// Try to find out if RTTI is disabled.
+#if defined(_LIBCPP_COMPILER_CLANG_BASED) && !__has_feature(cxx_rtti)
+#  define _LIBCPP_NO_RTTI
+#elif defined(__GNUC__) && !defined(__GXX_RTTI)
+#  define _LIBCPP_NO_RTTI
+#elif defined(_LIBCPP_COMPILER_MSVC) && !defined(_CPPRTTI)
+#  define _LIBCPP_NO_RTTI
+#endif
+
+#ifndef _LIBCPP_WEAK
+#define _LIBCPP_WEAK __attribute__((__weak__))
+#endif
+
+// Thread API
+#if !defined(_LIBCPP_HAS_NO_THREADS) && \
+    !defined(_LIBCPP_HAS_THREAD_API_PTHREAD) && \
+    !defined(_LIBCPP_HAS_THREAD_API_WIN32) && \
+    !defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
+#  if defined(__FreeBSD__) || \
+      defined(__wasi__) || \
+      defined(__NetBSD__) || \
+      defined(__OpenBSD__) || \
+      defined(__NuttX__) || \
+      defined(__linux__) || \
+      defined(__GNU__) || \
+      defined(__APPLE__) || \
+      defined(__sun__) || \
+      defined(__MVS__) || \
+      defined(_AIX) || \
+      defined(__CYGWIN__)
+#    define _LIBCPP_HAS_THREAD_API_PTHREAD
+#  elif defined(__Fuchsia__)
+     // TODO(44575): Switch to C11 thread API when possible.
+#    define _LIBCPP_HAS_THREAD_API_PTHREAD
+#  elif defined(_LIBCPP_WIN32API)
+#    define _LIBCPP_HAS_THREAD_API_WIN32
+#  else
+#    error "No thread API"
+#  endif // _LIBCPP_HAS_THREAD_API
+#endif // _LIBCPP_HAS_NO_THREADS
+
+#if defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
+#if defined(__ANDROID__) && __ANDROID_API__ >= 30
+#define _LIBCPP_HAS_COND_CLOCKWAIT
+#elif defined(_LIBCPP_GLIBC_PREREQ)
+#if _LIBCPP_GLIBC_PREREQ(2, 30)
+#define _LIBCPP_HAS_COND_CLOCKWAIT
+#endif
+#endif
+#endif
+
+#if defined(_LIBCPP_HAS_NO_THREADS) && defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
+#error _LIBCPP_HAS_THREAD_API_PTHREAD may only be defined when \
+       _LIBCPP_HAS_NO_THREADS is not defined.
+#endif
+
+#if defined(_LIBCPP_HAS_NO_THREADS) && defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
+#error _LIBCPP_HAS_THREAD_API_EXTERNAL may not be defined when \
+       _LIBCPP_HAS_NO_THREADS is defined.
+#endif
+
+#if defined(_LIBCPP_HAS_NO_MONOTONIC_CLOCK) && !defined(_LIBCPP_HAS_NO_THREADS)
+#error _LIBCPP_HAS_NO_MONOTONIC_CLOCK may only be defined when \
+       _LIBCPP_HAS_NO_THREADS is defined.
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(__STDCPP_THREADS__)
+#define __STDCPP_THREADS__ 1
+#endif
+
+// The glibc and Bionic implementation of pthreads implements
+// pthread_mutex_destroy as nop for regular mutexes. Additionally, Win32
+// mutexes have no destroy mechanism.
+//
+// This optimization can't be performed on Apple platforms, where
+// pthread_mutex_destroy can allow the kernel to release resources.
+// See https://llvm.org/D64298 for details.
+//
+// TODO(EricWF): Enable this optimization on Bionic after speaking to their
+//               respective stakeholders.
+#if (defined(_LIBCPP_HAS_THREAD_API_PTHREAD) && defined(__GLIBC__)) \
+  || (defined(_LIBCPP_HAS_THREAD_API_C11) && defined(__Fuchsia__)) \
+  || defined(_LIBCPP_HAS_THREAD_API_WIN32)
+# define _LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION
+#endif
+
+// Destroying a condvar is a nop on Windows.
+//
+// This optimization can't be performed on Apple platforms, where
+// pthread_cond_destroy can allow the kernel to release resources.
+// See https://llvm.org/D64298 for details.
+//
+// TODO(EricWF): This is potentially true for some pthread implementations
+// as well.
+#if (defined(_LIBCPP_HAS_THREAD_API_C11) && defined(__Fuchsia__)) || \
+     defined(_LIBCPP_HAS_THREAD_API_WIN32)
+# define _LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION
+#endif
+
+// Some systems do not provide gets() in their C library, for security reasons.
+#if defined(_LIBCPP_MSVCRT) || \
+    (defined(__FreeBSD_version) && __FreeBSD_version >= 1300043) || \
+    defined(__OpenBSD__)
+#   define _LIBCPP_C_HAS_NO_GETS
+#endif
+
+#if defined(__BIONIC__) || defined(__NuttX__) ||      \
+    defined(__Fuchsia__) || defined(__wasi__) || defined(_LIBCPP_HAS_MUSL_LIBC) || \
+    defined(__MVS__) || defined(__OpenBSD__)
+#define _LIBCPP_PROVIDES_DEFAULT_RUNE_TABLE
+#endif
+
+#if __has_feature(cxx_atomic) || __has_extension(c_atomic) || __has_keyword(_Atomic)
+#  define _LIBCPP_HAS_C_ATOMIC_IMP
+#elif defined(_LIBCPP_COMPILER_GCC)
+#  define _LIBCPP_HAS_GCC_ATOMIC_IMP
+#endif
+
+#if (!defined(_LIBCPP_HAS_C_ATOMIC_IMP) && \
+     !defined(_LIBCPP_HAS_GCC_ATOMIC_IMP) && \
+     !defined(_LIBCPP_COMPILER_MSVC) && \
+     !defined(_LIBCPP_HAS_EXTERNAL_ATOMIC_IMP)) \
+     || defined(_LIBCPP_HAS_NO_THREADS)
+#  define _LIBCPP_HAS_NO_ATOMIC_HEADER
+#else
+#  ifndef _LIBCPP_ATOMIC_FLAG_TYPE
+#    define _LIBCPP_ATOMIC_FLAG_TYPE bool
+#  endif
+#  ifdef _LIBCPP_FREESTANDING
+#    define _LIBCPP_ATOMIC_ONLY_USE_BUILTINS
+#  endif
+#endif
+
+#ifndef _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+#define _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+#endif
+
+#if defined(_LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS)
+#  if defined(__clang__) && __has_attribute(acquire_capability)
+// Work around the attribute handling in clang.  When both __declspec and
+// __attribute__ are present, the processing goes awry preventing the definition
+// of the types.
+#    if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
+#      define _LIBCPP_HAS_THREAD_SAFETY_ANNOTATIONS
+#    endif
+#  endif
+#endif
+
+#ifdef _LIBCPP_HAS_THREAD_SAFETY_ANNOTATIONS
+#   define _LIBCPP_THREAD_SAFETY_ANNOTATION(x) __attribute__((x))
+#else
+#   define _LIBCPP_THREAD_SAFETY_ANNOTATION(x)
+#endif
+
+#if __has_attribute(require_constant_initialization)
+#  define _LIBCPP_SAFE_STATIC __attribute__((__require_constant_initialization__))
+#else
+#  define _LIBCPP_SAFE_STATIC
+#endif
+
+#if !__has_builtin(__builtin_is_constant_evaluated) || (defined(_LIBCPP_COMPILER_GCC) && _GNUC_VER < 900) || __CUDACC_VER_MAJOR__ == 10
+#define _LIBCPP_HAS_NO_BUILTIN_IS_CONSTANT_EVALUATED
+#endif
+
+#if __has_attribute(diagnose_if) && !defined(_LIBCPP_DISABLE_ADDITIONAL_DIAGNOSTICS)
+#  define _LIBCPP_DIAGNOSE_WARNING(...) \
+     __attribute__((diagnose_if(__VA_ARGS__, "warning")))
+#  define _LIBCPP_DIAGNOSE_ERROR(...) \
+     __attribute__((diagnose_if(__VA_ARGS__, "error")))
+#else
+#  define _LIBCPP_DIAGNOSE_WARNING(...)
+#  define _LIBCPP_DIAGNOSE_ERROR(...)
+#endif
+
+// Use a function like macro to imply that it must be followed by a semicolon
+#if __cplusplus > 201402L && __has_cpp_attribute(fallthrough)
+#  define _LIBCPP_FALLTHROUGH() [[fallthrough]]
+#elif __has_cpp_attribute(clang::fallthrough)
+#  define _LIBCPP_FALLTHROUGH() [[clang::fallthrough]]
+#elif __has_attribute(__fallthrough__)
+#  define _LIBCPP_FALLTHROUGH() __attribute__((__fallthrough__))
+#else
+#  define _LIBCPP_FALLTHROUGH() ((void)0)
+#endif
+
+#if __has_attribute(__nodebug__) && !defined(__CUDACC__)
+#define _LIBCPP_NODEBUG __attribute__((__nodebug__))
+#else
+#define _LIBCPP_NODEBUG
+#endif
+
+#if __has_attribute(__standalone_debug__)
+#define _LIBCPP_STANDALONE_DEBUG __attribute__((__standalone_debug__))
+#else
+#define _LIBCPP_STANDALONE_DEBUG
+#endif
+
+#if __has_attribute(__preferred_name__)
+#define _LIBCPP_PREFERRED_NAME(x) __attribute__((__preferred_name__(x)))
+#else
+#define _LIBCPP_PREFERRED_NAME(x)
+#endif
+
+// We often repeat things just for handling wide characters in the library.
+// When wide characters are disabled, it can be useful to have a quick way of
+// disabling it without having to resort to #if-#endif, which has a larger
+// impact on readability.
+#if defined(_LIBCPP_HAS_NO_WIDE_CHARACTERS)
+# define _LIBCPP_IF_WIDE_CHARACTERS(...)
+#else
+# define _LIBCPP_IF_WIDE_CHARACTERS(...) __VA_ARGS__
+#endif
+
+#if defined(_LIBCPP_ABI_MICROSOFT) && \
+   (defined(_LIBCPP_COMPILER_MSVC) || __has_declspec_attribute(empty_bases)) && \
+    !defined(__CUDACC__)
+#  define _LIBCPP_DECLSPEC_EMPTY_BASES __declspec(empty_bases)
+#else
+#  define _LIBCPP_DECLSPEC_EMPTY_BASES
+#endif
+
+#if defined(_LIBCPP_ENABLE_CXX17_REMOVED_FEATURES)
+#define _LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR
+#define _LIBCPP_ENABLE_CXX17_REMOVED_BINDERS
+#define _LIBCPP_ENABLE_CXX17_REMOVED_RANDOM_SHUFFLE
+#define _LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS
+#endif // _LIBCPP_ENABLE_CXX17_REMOVED_FEATURES
+
+#if defined(_LIBCPP_ENABLE_CXX20_REMOVED_FEATURES)
+#define _LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS
+#define _LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS
+#define _LIBCPP_ENABLE_CXX20_REMOVED_NEGATORS
+#define _LIBCPP_ENABLE_CXX20_REMOVED_RAW_STORAGE_ITERATOR
+#define _LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS
+#endif // _LIBCPP_ENABLE_CXX20_REMOVED_FEATURES
+
+#if !defined(__cpp_coroutines) || __cpp_coroutines < 201703L
+#define _LIBCPP_HAS_NO_COROUTINES
+#endif
+
+#if !defined(__cpp_impl_three_way_comparison) || __cpp_impl_three_way_comparison < 201907L
+#define _LIBCPP_HAS_NO_SPACESHIP_OPERATOR
+#endif
+
+// Yandex-specific: We build our own libc++, so it has everything available
+#define _LIBCPP_DISABLE_AVAILABILITY
+// End of Yandex-specific
+
+#if defined(_LIBCPP_COMPILER_IBM) || defined(__CUDACC__)
+#define _LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO
+#endif
+
+#if defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+#  define _LIBCPP_PUSH_MACROS
+#  define _LIBCPP_POP_MACROS
+#else
+  // Don't warn about macro conflicts when we can restore them at the
+  // end of the header.
+#  ifndef _LIBCPP_DISABLE_MACRO_CONFLICT_WARNINGS
+#    define _LIBCPP_DISABLE_MACRO_CONFLICT_WARNINGS
+#  endif
+#  if defined(_LIBCPP_COMPILER_MSVC)
+#    define _LIBCPP_PUSH_MACROS    \
+       __pragma(push_macro("min")) \
+       __pragma(push_macro("max"))
+#    define _LIBCPP_POP_MACROS     \
+       __pragma(pop_macro("min"))  \
+       __pragma(pop_macro("max"))
+#  else
+#    define _LIBCPP_PUSH_MACROS        \
+       _Pragma("push_macro(\"min\")")  \
+       _Pragma("push_macro(\"max\")")
+#    define _LIBCPP_POP_MACROS         \
+       _Pragma("pop_macro(\"min\")")   \
+       _Pragma("pop_macro(\"max\")")
+#  endif
+#endif // defined(_LIBCPP_HAS_NO_PRAGMA_PUSH_POP_MACRO)
+
+#ifndef _LIBCPP_NO_AUTO_LINK
+#  if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_BUILDING_LIBRARY)
+#    if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+#      pragma comment(lib, "c++.lib")
+#    else
+#      pragma comment(lib, "libc++.lib")
+#    endif
+#  endif // defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_BUILDING_LIBRARY)
+#endif // _LIBCPP_NO_AUTO_LINK
+
+// Configures the fopen close-on-exec mode character, if any. This string will
+// be appended to any mode string used by fstream for fopen/fdopen.
+//
+// Not all platforms support this, but it helps avoid fd-leaks on platforms that
+// do.
+#if defined(__BIONIC__)
+#  define _LIBCPP_FOPEN_CLOEXEC_MODE "e"
+#else
+#  define _LIBCPP_FOPEN_CLOEXEC_MODE
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#define _LIBCPP_BUILTIN_CONSTANT_P(x) false
+#else
+#define _LIBCPP_BUILTIN_CONSTANT_P(x) __builtin_constant_p(x)
+#endif
+
+// Support for _FILE_OFFSET_BITS=64 landed gradually in Android, so the full set
+// of functions used in cstdio may not be available for low API levels when
+// using 64-bit file offsets on LP32.
+#if defined(__BIONIC__) && defined(__USE_FILE_OFFSET64) && __ANDROID_API__ < 24
+#define _LIBCPP_HAS_NO_FGETPOS_FSETPOS
+#endif
+
+#if __has_attribute(init_priority)
+    // TODO: Remove this once we drop support for building libc++ with old Clangs
+#   if (defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1200) || \
+       (defined(__apple_build_version__) && __apple_build_version__ < 13000000)
+#     define _LIBCPP_INIT_PRIORITY_MAX __attribute__((init_priority(101)))
+#   else
+#     define _LIBCPP_INIT_PRIORITY_MAX __attribute__((init_priority(100)))
+#   endif
+#else
+# define _LIBCPP_INIT_PRIORITY_MAX
+#endif
+
+#if defined(__GNUC__) || defined(__clang__)
+#define _LIBCPP_FORMAT_PRINTF(a, b)                                            \
+  __attribute__((__format__(__printf__, a, b)))
+#else
+#define _LIBCPP_FORMAT_PRINTF(a, b)
+#endif
+
+#endif // __cplusplus
+
+#endif // _LIBCPP_CONFIG
diff --git a/contrib/libs/cxxsupp/libcxx/include/__config_site.in b/contrib/libs/cxxsupp/libcxx/include/__config_site.in
new file mode 100644
index 00000000000..a8b17ad72b7
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__config_site.in
@@ -0,0 +1,39 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CONFIG_SITE
+#define _LIBCPP_CONFIG_SITE
+
+#cmakedefine _LIBCPP_ABI_VERSION @_LIBCPP_ABI_VERSION@
+#cmakedefine _LIBCPP_ABI_UNSTABLE
+#cmakedefine _LIBCPP_ABI_FORCE_ITANIUM
+#cmakedefine _LIBCPP_ABI_FORCE_MICROSOFT
+#cmakedefine _LIBCPP_HIDE_FROM_ABI_PER_TU_BY_DEFAULT
+#cmakedefine _LIBCPP_HAS_NO_THREADS
+#cmakedefine _LIBCPP_HAS_NO_MONOTONIC_CLOCK
+#cmakedefine _LIBCPP_HAS_MUSL_LIBC
+#cmakedefine _LIBCPP_HAS_THREAD_API_PTHREAD
+#cmakedefine _LIBCPP_HAS_THREAD_API_EXTERNAL
+#cmakedefine _LIBCPP_HAS_THREAD_API_WIN32
+#cmakedefine _LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL
+#cmakedefine _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS
+#cmakedefine _LIBCPP_HAS_NO_VENDOR_AVAILABILITY_ANNOTATIONS
+#cmakedefine _LIBCPP_NO_VCRUNTIME
+#cmakedefine _LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION @_LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION@
+#cmakedefine _LIBCPP_ABI_NAMESPACE @_LIBCPP_ABI_NAMESPACE@
+#cmakedefine _LIBCPP_HAS_NO_FILESYSTEM_LIBRARY
+#cmakedefine _LIBCPP_HAS_PARALLEL_ALGORITHMS
+#cmakedefine _LIBCPP_HAS_NO_RANDOM_DEVICE
+#cmakedefine _LIBCPP_HAS_NO_LOCALIZATION
+#cmakedefine _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#cmakedefine _LIBCPP_HAS_NO_INCOMPLETE_FORMAT
+#cmakedefine _LIBCPP_HAS_NO_INCOMPLETE_RANGES
+
+@_LIBCPP_ABI_DEFINES@
+
+#endif // _LIBCPP_CONFIG_SITE
diff --git a/contrib/libs/cxxsupp/libcxx/include/__debug b/contrib/libs/cxxsupp/libcxx/include/__debug
new file mode 100644
index 00000000000..771e4316320
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__debug
@@ -0,0 +1,273 @@
+// -*- C++ -*-
+//===--------------------------- __debug ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_DEBUG_H
+#define _LIBCPP_DEBUG_H
+
+#include <__config>
+#include <iosfwd>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#if defined(_LIBCPP_HAS_NO_NULLPTR)
+# include <cstddef>
+#endif
+
+#if _LIBCPP_DEBUG_LEVEL >= 1 || defined(_LIBCPP_BUILDING_LIBRARY)
+#   include <cstdlib>
+#   include <cstdio>
+#   include <cstddef>
+#endif
+
+#if _LIBCPP_DEBUG_LEVEL == 0
+#   define _LIBCPP_DEBUG_ASSERT(x, m) ((void)0)
+#   define _LIBCPP_ASSERT_IMPL(x, m) ((void)0)
+#elif _LIBCPP_DEBUG_LEVEL == 1
+#   define _LIBCPP_DEBUG_ASSERT(x, m) ((void)0)
+#   define _LIBCPP_ASSERT_IMPL(x, m) ((x) ? (void)0 : _VSTD::__libcpp_debug_function(_VSTD::__libcpp_debug_info(__FILE__, __LINE__, #x, m)))
+#elif _LIBCPP_DEBUG_LEVEL == 2
+#   define _LIBCPP_DEBUG_ASSERT(x, m) _LIBCPP_ASSERT(x, m)
+#   define _LIBCPP_ASSERT_IMPL(x, m) ((x) ? (void)0 : _VSTD::__libcpp_debug_function(_VSTD::__libcpp_debug_info(__FILE__, __LINE__, #x, m)))
+#else
+#   error _LIBCPP_DEBUG_LEVEL must be one of 0, 1, 2
+#endif
+
+#if !defined(_LIBCPP_ASSERT)
+#   define _LIBCPP_ASSERT(x, m) _LIBCPP_ASSERT_IMPL(x, m)
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+struct _LIBCPP_TEMPLATE_VIS __libcpp_debug_info {
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+  __libcpp_debug_info()
+      : __file_(nullptr), __line_(-1), __pred_(nullptr), __msg_(nullptr) {}
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+  __libcpp_debug_info(const char* __f, int __l, const char* __p, const char* __m)
+    : __file_(__f), __line_(__l), __pred_(__p), __msg_(__m) {}
+
+  _LIBCPP_FUNC_VIS string what() const;
+
+  const char* __file_;
+  int __line_;
+  const char* __pred_;
+  const char* __msg_;
+};
+
+/// __libcpp_debug_function_type - The type of the assertion failure handler.
+typedef void(*__libcpp_debug_function_type)(__libcpp_debug_info const&);
+
+/// __libcpp_debug_function - The handler function called when a _LIBCPP_ASSERT
+///    fails.
+extern _LIBCPP_EXPORTED_FROM_ABI __libcpp_debug_function_type __libcpp_debug_function;
+
+/// __libcpp_abort_debug_function - A debug handler that aborts when called.
+_LIBCPP_NORETURN _LIBCPP_FUNC_VIS
+void __libcpp_abort_debug_function(__libcpp_debug_info const&);
+
+/// __libcpp_set_debug_function - Set the debug handler to the specified
+///    function.
+_LIBCPP_FUNC_VIS
+bool __libcpp_set_debug_function(__libcpp_debug_function_type __func);
+
+#if _LIBCPP_DEBUG_LEVEL == 2 || defined(_LIBCPP_BUILDING_LIBRARY)
+
+struct _LIBCPP_TYPE_VIS __c_node;
+
+struct _LIBCPP_TYPE_VIS __i_node
+{
+    void* __i_;
+    __i_node* __next_;
+    __c_node* __c_;
+
+#ifndef _LIBCPP_CXX03_LANG
+    __i_node(const __i_node&) = delete;
+    __i_node& operator=(const __i_node&) = delete;
+#else
+private:
+    __i_node(const __i_node&);
+    __i_node& operator=(const __i_node&);
+public:
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    __i_node(void* __i, __i_node* __next, __c_node* __c)
+        : __i_(__i), __next_(__next), __c_(__c) {}
+    ~__i_node();
+};
+
+struct _LIBCPP_TYPE_VIS __c_node
+{
+    void* __c_;
+    __c_node* __next_;
+    __i_node** beg_;
+    __i_node** end_;
+    __i_node** cap_;
+
+#ifndef _LIBCPP_CXX03_LANG
+    __c_node(const __c_node&) = delete;
+    __c_node& operator=(const __c_node&) = delete;
+#else
+private:
+    __c_node(const __c_node&);
+    __c_node& operator=(const __c_node&);
+public:
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    __c_node(void* __c, __c_node* __next)
+        : __c_(__c), __next_(__next), beg_(nullptr), end_(nullptr), cap_(nullptr) {}
+    virtual ~__c_node();
+
+    virtual bool __dereferenceable(const void*) const = 0;
+    virtual bool __decrementable(const void*) const = 0;
+    virtual bool __addable(const void*, ptrdiff_t) const = 0;
+    virtual bool __subscriptable(const void*, ptrdiff_t) const = 0;
+
+    void __add(__i_node* __i);
+    _LIBCPP_HIDDEN void __remove(__i_node* __i);
+};
+
+template <class _Cont>
+struct _C_node
+    : public __c_node
+{
+    _C_node(void* __c, __c_node* __n)
+        : __c_node(__c, __n) {}
+
+    virtual bool __dereferenceable(const void*) const;
+    virtual bool __decrementable(const void*) const;
+    virtual bool __addable(const void*, ptrdiff_t) const;
+    virtual bool __subscriptable(const void*, ptrdiff_t) const;
+};
+
+template <class _Cont>
+inline bool
+_C_node<_Cont>::__dereferenceable(const void* __i) const
+{
+    typedef typename _Cont::const_iterator iterator;
+    const iterator* __j = static_cast<const iterator*>(__i);
+    _Cont* _Cp = static_cast<_Cont*>(__c_);
+    return _Cp->__dereferenceable(__j);
+}
+
+template <class _Cont>
+inline bool
+_C_node<_Cont>::__decrementable(const void* __i) const
+{
+    typedef typename _Cont::const_iterator iterator;
+    const iterator* __j = static_cast<const iterator*>(__i);
+    _Cont* _Cp = static_cast<_Cont*>(__c_);
+    return _Cp->__decrementable(__j);
+}
+
+template <class _Cont>
+inline bool
+_C_node<_Cont>::__addable(const void* __i, ptrdiff_t __n) const
+{
+    typedef typename _Cont::const_iterator iterator;
+    const iterator* __j = static_cast<const iterator*>(__i);
+    _Cont* _Cp = static_cast<_Cont*>(__c_);
+    return _Cp->__addable(__j, __n);
+}
+
+template <class _Cont>
+inline bool
+_C_node<_Cont>::__subscriptable(const void* __i, ptrdiff_t __n) const
+{
+    typedef typename _Cont::const_iterator iterator;
+    const iterator* __j = static_cast<const iterator*>(__i);
+    _Cont* _Cp = static_cast<_Cont*>(__c_);
+    return _Cp->__subscriptable(__j, __n);
+}
+
+class _LIBCPP_TYPE_VIS __libcpp_db
+{
+    __c_node** __cbeg_;
+    __c_node** __cend_;
+    size_t   __csz_;
+    __i_node** __ibeg_;
+    __i_node** __iend_;
+    size_t   __isz_;
+
+    __libcpp_db();
+public:
+#ifndef _LIBCPP_CXX03_LANG
+    __libcpp_db(const __libcpp_db&) = delete;
+    __libcpp_db& operator=(const __libcpp_db&) = delete;
+#else
+private:
+    __libcpp_db(const __libcpp_db&);
+    __libcpp_db& operator=(const __libcpp_db&);
+public:
+#endif
+    ~__libcpp_db();
+
+    class __db_c_iterator;
+    class __db_c_const_iterator;
+    class __db_i_iterator;
+    class __db_i_const_iterator;
+
+    __db_c_const_iterator __c_end() const;
+    __db_i_const_iterator __i_end() const;
+
+    typedef __c_node*(_InsertConstruct)(void*, void*, __c_node*);
+
+    template <class _Cont>
+    _LIBCPP_INLINE_VISIBILITY static __c_node* __create_C_node(void *__mem, void *__c, __c_node *__next) {
+        return ::new (__mem) _C_node<_Cont>(__c, __next);
+    }
+
+    template <class _Cont>
+    _LIBCPP_INLINE_VISIBILITY
+    void __insert_c(_Cont* __c)
+    {
+        __insert_c(static_cast<void*>(__c), &__create_C_node<_Cont>);
+    }
+
+    void __insert_i(void* __i);
+    void __insert_c(void* __c, _InsertConstruct* __fn);
+    void __erase_c(void* __c);
+
+    void __insert_ic(void* __i, const void* __c);
+    void __iterator_copy(void* __i, const void* __i0);
+    void __erase_i(void* __i);
+
+    void* __find_c_from_i(void* __i) const;
+    void __invalidate_all(void* __c);
+    __c_node* __find_c_and_lock(void* __c) const;
+    __c_node* __find_c(void* __c) const;
+    void unlock() const;
+
+    void swap(void* __c1, void* __c2);
+
+
+    bool __dereferenceable(const void* __i) const;
+    bool __decrementable(const void* __i) const;
+    bool __addable(const void* __i, ptrdiff_t __n) const;
+    bool __subscriptable(const void* __i, ptrdiff_t __n) const;
+    bool __less_than_comparable(const void* __i, const void* __j) const;
+private:
+    _LIBCPP_HIDDEN
+    __i_node* __insert_iterator(void* __i);
+    _LIBCPP_HIDDEN
+    __i_node* __find_iterator(const void* __i) const;
+
+    friend _LIBCPP_FUNC_VIS __libcpp_db* __get_db();
+};
+
+_LIBCPP_FUNC_VIS __libcpp_db* __get_db();
+_LIBCPP_FUNC_VIS const __libcpp_db* __get_const_db();
+
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2 || defined(_LIBCPP_BUILDING_LIBRARY)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_DEBUG_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__errc b/contrib/libs/cxxsupp/libcxx/include/__errc
new file mode 100644
index 00000000000..81da2e1970c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__errc
@@ -0,0 +1,217 @@
+// -*- C++ -*-
+//===---------------------------- __errc ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ERRC
+#define _LIBCPP___ERRC
+
+/*
+    system_error synopsis
+
+namespace std
+{
+
+enum class errc
+{
+    address_family_not_supported,       // EAFNOSUPPORT
+    address_in_use,                     // EADDRINUSE
+    address_not_available,              // EADDRNOTAVAIL
+    already_connected,                  // EISCONN
+    argument_list_too_long,             // E2BIG
+    argument_out_of_domain,             // EDOM
+    bad_address,                        // EFAULT
+    bad_file_descriptor,                // EBADF
+    bad_message,                        // EBADMSG
+    broken_pipe,                        // EPIPE
+    connection_aborted,                 // ECONNABORTED
+    connection_already_in_progress,     // EALREADY
+    connection_refused,                 // ECONNREFUSED
+    connection_reset,                   // ECONNRESET
+    cross_device_link,                  // EXDEV
+    destination_address_required,       // EDESTADDRREQ
+    device_or_resource_busy,            // EBUSY
+    directory_not_empty,                // ENOTEMPTY
+    executable_format_error,            // ENOEXEC
+    file_exists,                        // EEXIST
+    file_too_large,                     // EFBIG
+    filename_too_long,                  // ENAMETOOLONG
+    function_not_supported,             // ENOSYS
+    host_unreachable,                   // EHOSTUNREACH
+    identifier_removed,                 // EIDRM
+    illegal_byte_sequence,              // EILSEQ
+    inappropriate_io_control_operation, // ENOTTY
+    interrupted,                        // EINTR
+    invalid_argument,                   // EINVAL
+    invalid_seek,                       // ESPIPE
+    io_error,                           // EIO
+    is_a_directory,                     // EISDIR
+    message_size,                       // EMSGSIZE
+    network_down,                       // ENETDOWN
+    network_reset,                      // ENETRESET
+    network_unreachable,                // ENETUNREACH
+    no_buffer_space,                    // ENOBUFS
+    no_child_process,                   // ECHILD
+    no_link,                            // ENOLINK
+    no_lock_available,                  // ENOLCK
+    no_message_available,               // ENODATA
+    no_message,                         // ENOMSG
+    no_protocol_option,                 // ENOPROTOOPT
+    no_space_on_device,                 // ENOSPC
+    no_stream_resources,                // ENOSR
+    no_such_device_or_address,          // ENXIO
+    no_such_device,                     // ENODEV
+    no_such_file_or_directory,          // ENOENT
+    no_such_process,                    // ESRCH
+    not_a_directory,                    // ENOTDIR
+    not_a_socket,                       // ENOTSOCK
+    not_a_stream,                       // ENOSTR
+    not_connected,                      // ENOTCONN
+    not_enough_memory,                  // ENOMEM
+    not_supported,                      // ENOTSUP
+    operation_canceled,                 // ECANCELED
+    operation_in_progress,              // EINPROGRESS
+    operation_not_permitted,            // EPERM
+    operation_not_supported,            // EOPNOTSUPP
+    operation_would_block,              // EWOULDBLOCK
+    owner_dead,                         // EOWNERDEAD
+    permission_denied,                  // EACCES
+    protocol_error,                     // EPROTO
+    protocol_not_supported,             // EPROTONOSUPPORT
+    read_only_file_system,              // EROFS
+    resource_deadlock_would_occur,      // EDEADLK
+    resource_unavailable_try_again,     // EAGAIN
+    result_out_of_range,                // ERANGE
+    state_not_recoverable,              // ENOTRECOVERABLE
+    stream_timeout,                     // ETIME
+    text_file_busy,                     // ETXTBSY
+    timed_out,                          // ETIMEDOUT
+    too_many_files_open_in_system,      // ENFILE
+    too_many_files_open,                // EMFILE
+    too_many_links,                     // EMLINK
+    too_many_symbolic_link_levels,      // ELOOP
+    value_too_large,                    // EOVERFLOW
+    wrong_protocol_type                 // EPROTOTYPE
+};
+
+*/
+
+#include <__config>
+#include <cerrno>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Some error codes are not present on all platforms, so we provide equivalents
+// for them:
+
+//enum class errc
+_LIBCPP_DECLARE_STRONG_ENUM(errc)
+{
+    address_family_not_supported        = EAFNOSUPPORT,
+    address_in_use                      = EADDRINUSE,
+    address_not_available               = EADDRNOTAVAIL,
+    already_connected                   = EISCONN,
+    argument_list_too_long              = E2BIG,
+    argument_out_of_domain              = EDOM,
+    bad_address                         = EFAULT,
+    bad_file_descriptor                 = EBADF,
+    bad_message                         = EBADMSG,
+    broken_pipe                         = EPIPE,
+    connection_aborted                  = ECONNABORTED,
+    connection_already_in_progress      = EALREADY,
+    connection_refused                  = ECONNREFUSED,
+    connection_reset                    = ECONNRESET,
+    cross_device_link                   = EXDEV,
+    destination_address_required        = EDESTADDRREQ,
+    device_or_resource_busy             = EBUSY,
+    directory_not_empty                 = ENOTEMPTY,
+    executable_format_error             = ENOEXEC,
+    file_exists                         = EEXIST,
+    file_too_large                      = EFBIG,
+    filename_too_long                   = ENAMETOOLONG,
+    function_not_supported              = ENOSYS,
+    host_unreachable                    = EHOSTUNREACH,
+    identifier_removed                  = EIDRM,
+    illegal_byte_sequence               = EILSEQ,
+    inappropriate_io_control_operation  = ENOTTY,
+    interrupted                         = EINTR,
+    invalid_argument                    = EINVAL,
+    invalid_seek                        = ESPIPE,
+    io_error                            = EIO,
+    is_a_directory                      = EISDIR,
+    message_size                        = EMSGSIZE,
+    network_down                        = ENETDOWN,
+    network_reset                       = ENETRESET,
+    network_unreachable                 = ENETUNREACH,
+    no_buffer_space                     = ENOBUFS,
+    no_child_process                    = ECHILD,
+    no_link                             = ENOLINK,
+    no_lock_available                   = ENOLCK,
+#ifdef ENODATA
+    no_message_available                = ENODATA,
+#else
+    no_message_available                = ENOMSG,
+#endif
+    no_message                          = ENOMSG,
+    no_protocol_option                  = ENOPROTOOPT,
+    no_space_on_device                  = ENOSPC,
+#ifdef ENOSR
+    no_stream_resources                 = ENOSR,
+#else
+    no_stream_resources                 = ENOMEM,
+#endif
+    no_such_device_or_address           = ENXIO,
+    no_such_device                      = ENODEV,
+    no_such_file_or_directory           = ENOENT,
+    no_such_process                     = ESRCH,
+    not_a_directory                     = ENOTDIR,
+    not_a_socket                        = ENOTSOCK,
+#ifdef ENOSTR
+    not_a_stream                        = ENOSTR,
+#else
+    not_a_stream                        = EINVAL,
+#endif
+    not_connected                       = ENOTCONN,
+    not_enough_memory                   = ENOMEM,
+    not_supported                       = ENOTSUP,
+    operation_canceled                  = ECANCELED,
+    operation_in_progress               = EINPROGRESS,
+    operation_not_permitted             = EPERM,
+    operation_not_supported             = EOPNOTSUPP,
+    operation_would_block               = EWOULDBLOCK,
+    owner_dead                          = EOWNERDEAD,
+    permission_denied                   = EACCES,
+    protocol_error                      = EPROTO,
+    protocol_not_supported              = EPROTONOSUPPORT,
+    read_only_file_system               = EROFS,
+    resource_deadlock_would_occur       = EDEADLK,
+    resource_unavailable_try_again      = EAGAIN,
+    result_out_of_range                 = ERANGE,
+    state_not_recoverable               = ENOTRECOVERABLE,
+#ifdef ETIME
+    stream_timeout                      = ETIME,
+#else
+    stream_timeout                      = ETIMEDOUT,
+#endif
+    text_file_busy                      = ETXTBSY,
+    timed_out                           = ETIMEDOUT,
+    too_many_files_open_in_system       = ENFILE,
+    too_many_files_open                 = EMFILE,
+    too_many_links                      = EMLINK,
+    too_many_symbolic_link_levels       = ELOOP,
+    value_too_large                     = EOVERFLOW,
+    wrong_protocol_type                 = EPROTOTYPE
+};
+_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(errc)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ERRC
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/format_arg.h b/contrib/libs/cxxsupp/libcxx/include/__format/format_arg.h
new file mode 100644
index 00000000000..a9a8c1f0da0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/format_arg.h
@@ -0,0 +1,256 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMAT_ARG_H
+#define _LIBCPP___FORMAT_FORMAT_ARG_H
+
+#include <__concepts/arithmetic.h>
+#include <__config>
+#include <__format/format_error.h>
+#include <__format/format_fwd.h>
+#include <__functional_base>
+#include <__variant/monostate.h>
+#include <string>
+#include <string_view>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+namespace __format {
+/** The type stored in @ref basic_format_arg. */
+enum class _LIBCPP_ENUM_VIS __arg_t : uint8_t {
+  __none,
+  __boolean,
+  __char_type,
+  __int,
+  __long_long,
+#ifndef _LIBCPP_HAS_NO_INT128
+  __i128,
+#endif
+  __unsigned,
+  __unsigned_long_long,
+#ifndef _LIBCPP_HAS_NO_INT128
+  __u128,
+#endif
+  __float,
+  __double,
+  __long_double,
+  __const_char_type_ptr,
+  __string_view,
+  __ptr
+};
+} // namespace __format
+
+template <class _Visitor, class _Context>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT decltype(auto)
+visit_format_arg(_Visitor&& __vis, basic_format_arg<_Context> __arg) {
+  switch (__arg.__type_) {
+  case __format::__arg_t::__none:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), monostate{});
+  case __format::__arg_t::__boolean:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__boolean);
+  case __format::__arg_t::__char_type:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__char_type);
+  case __format::__arg_t::__int:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__int);
+  case __format::__arg_t::__long_long:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__long_long);
+#ifndef _LIBCPP_HAS_NO_INT128
+  case __format::__arg_t::__i128:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__i128);
+#endif
+  case __format::__arg_t::__unsigned:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__unsigned);
+  case __format::__arg_t::__unsigned_long_long:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis),
+                         __arg.__unsigned_long_long);
+#ifndef _LIBCPP_HAS_NO_INT128
+  case __format::__arg_t::__u128:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__u128);
+#endif
+  case __format::__arg_t::__float:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__float);
+  case __format::__arg_t::__double:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__double);
+  case __format::__arg_t::__long_double:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__long_double);
+  case __format::__arg_t::__const_char_type_ptr:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis),
+                         __arg.__const_char_type_ptr);
+  case __format::__arg_t::__string_view:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__string_view);
+  case __format::__arg_t::__ptr:
+    return _VSTD::invoke(_VSTD::forward<_Visitor>(__vis), __arg.__ptr);
+  }
+  _LIBCPP_UNREACHABLE();
+}
+
+template <class _Context>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_arg {
+public:
+  // TODO FMT Define the handle class.
+  class handle;
+
+  _LIBCPP_HIDE_FROM_ABI basic_format_arg() noexcept
+      : __type_{__format::__arg_t::__none} {}
+
+  _LIBCPP_HIDE_FROM_ABI explicit operator bool() const noexcept {
+    return __type_ != __format::__arg_t::__none;
+  }
+
+private:
+  using char_type = typename _Context::char_type;
+
+  // TODO FMT Implement constrain [format.arg]/4
+  // Constraints: The template specialization
+  //   typename Context::template formatter_type<T>
+  // meets the Formatter requirements ([formatter.requirements]).  The extent
+  // to which an implementation determines that the specialization meets the
+  // Formatter requirements is unspecified, except that as a minimum the
+  // expression
+  //   typename Context::template formatter_type<T>()
+  //    .format(declval<const T&>(), declval<Context&>())
+  // shall be well-formed when treated as an unevaluated operand.
+
+  template <class _Ctx, class... _Args>
+  _LIBCPP_HIDE_FROM_ABI
+      _LIBCPP_AVAILABILITY_FORMAT friend __format_arg_store<_Ctx, _Args...>
+      _VSTD::make_format_args(const _Args&...);
+
+  template <class _Visitor, class _Ctx>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT friend decltype(auto)
+  _VSTD::visit_format_arg(_Visitor&& __vis, basic_format_arg<_Ctx> __arg);
+
+  union {
+    bool __boolean;
+    char_type __char_type;
+    int __int;
+    unsigned __unsigned;
+    long long __long_long;
+    unsigned long long __unsigned_long_long;
+#ifndef _LIBCPP_HAS_NO_INT128
+    __int128_t __i128;
+    __uint128_t __u128;
+#endif
+    float __float;
+    double __double;
+    long double __long_double;
+    const char_type* __const_char_type_ptr;
+    basic_string_view<char_type> __string_view;
+    const void* __ptr;
+    // TODO FMT Add the handle.
+  };
+  __format::__arg_t __type_;
+
+  _LIBCPP_HIDE_FROM_ABI explicit basic_format_arg(bool __v) noexcept
+      : __boolean(__v), __type_(__format::__arg_t::__boolean) {}
+
+  template <class _Tp>
+  _LIBCPP_HIDE_FROM_ABI explicit basic_format_arg(_Tp __v) noexcept
+      requires(same_as<_Tp, char_type> ||
+               (same_as<_Tp, char> && same_as<char_type, wchar_t>))
+      : __char_type(__v), __type_(__format::__arg_t::__char_type) {}
+
+  template <__libcpp_signed_integer _Tp>
+  _LIBCPP_HIDE_FROM_ABI explicit basic_format_arg(_Tp __v) noexcept {
+    if constexpr (sizeof(_Tp) <= sizeof(int)) {
+      __int = static_cast<int>(__v);
+      __type_ = __format::__arg_t::__int;
+    } else if constexpr (sizeof(_Tp) <= sizeof(long long)) {
+      __long_long = static_cast<long long>(__v);
+      __type_ = __format::__arg_t::__long_long;
+    }
+#ifndef _LIBCPP_HAS_NO_INT128
+    else if constexpr (sizeof(_Tp) == sizeof(__int128_t)) {
+      __i128 = __v;
+      __type_ = __format::__arg_t::__i128;
+    }
+#endif
+    else
+      static_assert(sizeof(_Tp) == 0, "An unsupported signed integer was used");
+  }
+
+  template <__libcpp_unsigned_integer _Tp>
+  _LIBCPP_HIDE_FROM_ABI explicit basic_format_arg(_Tp __v) noexcept {
+    if constexpr (sizeof(_Tp) <= sizeof(unsigned)) {
+      __unsigned = static_cast<unsigned>(__v);
+      __type_ = __format::__arg_t::__unsigned;
+    } else if constexpr (sizeof(_Tp) <= sizeof(unsigned long long)) {
+      __unsigned_long_long = static_cast<unsigned long long>(__v);
+      __type_ = __format::__arg_t::__unsigned_long_long;
+    }
+#ifndef _LIBCPP_HAS_NO_INT128
+    else if constexpr (sizeof(_Tp) == sizeof(__int128_t)) {
+      __u128 = __v;
+      __type_ = __format::__arg_t::__u128;
+    }
+#endif
+    else
+      static_assert(sizeof(_Tp) == 0,
+                    "An unsupported unsigned integer was used");
+  }
+
+  _LIBCPP_HIDE_FROM_ABI explicit basic_format_arg(float __v) noexcept
+      : __float(__v), __type_(__format::__arg_t::__float) {}
+
+  _LIBCPP_HIDE_FROM_ABI explicit basic_format_arg(double __v) noexcept
+      : __double(__v), __type_(__format::__arg_t::__double) {}
+
+  _LIBCPP_HIDE_FROM_ABI explicit basic_format_arg(long double __v) noexcept
+      : __long_double(__v), __type_(__format::__arg_t::__long_double) {}
+
+  // Note not a 'noexcept' function.
+  _LIBCPP_HIDE_FROM_ABI explicit basic_format_arg(const char_type* __s)
+      : __const_char_type_ptr(__s),
+        __type_(__format::__arg_t::__const_char_type_ptr) {
+    _LIBCPP_ASSERT(__s, "Used a nullptr argument to initialize a C-string");
+  }
+
+  template <class _Traits>
+  _LIBCPP_HIDE_FROM_ABI explicit basic_format_arg(
+      basic_string_view<char_type, _Traits> __s) noexcept
+      : __string_view{__s.data(), __s.size()},
+        __type_(__format::__arg_t::__string_view) {}
+
+  template <class _Traits, class _Allocator>
+  _LIBCPP_HIDE_FROM_ABI explicit basic_format_arg(
+      const basic_string<char_type, _Traits, _Allocator>& __s) noexcept
+      : __string_view{__s.data(), __s.size()},
+        __type_(__format::__arg_t::__string_view) {}
+
+  _LIBCPP_HIDE_FROM_ABI
+  explicit basic_format_arg(nullptr_t) noexcept
+      : __ptr(nullptr), __type_(__format::__arg_t::__ptr) {}
+
+  // TODO FMT Implement the _Tp* constructor.
+};
+
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___FORMAT_FORMAT_ARG_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/format_args.h b/contrib/libs/cxxsupp/libcxx/include/__format/format_args.h
new file mode 100644
index 00000000000..0a26b95d1b4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/format_args.h
@@ -0,0 +1,71 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMAT_ARGS_H
+#define _LIBCPP___FORMAT_FORMAT_ARGS_H
+
+#include <__availability>
+#include <__config>
+#include <__format/format_fwd.h>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+template <class _Context>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_args {
+public:
+  // TODO FMT Implement [format.args]/5
+  // [Note 1: Implementations are encouraged to optimize the representation of
+  // basic_format_args for small number of formatting arguments by storing
+  // indices of type alternatives separately from values and packing the
+  // former. - end note]
+  // Note: Change  __format_arg_store to use a built-in array.
+  _LIBCPP_HIDE_FROM_ABI basic_format_args() noexcept = default;
+
+  template <class... _Args>
+  _LIBCPP_HIDE_FROM_ABI basic_format_args(
+      const __format_arg_store<_Context, _Args...>& __store) noexcept
+      : __size_(sizeof...(_Args)), __data_(__store.__args.data()) {}
+
+  _LIBCPP_HIDE_FROM_ABI
+  basic_format_arg<_Context> get(size_t __id) const noexcept {
+    return __id < __size_ ? __data_[__id] : basic_format_arg<_Context>{};
+  }
+
+  _LIBCPP_HIDE_FROM_ABI size_t __size() const noexcept { return __size_; }
+
+private:
+  size_t __size_{0};
+  const basic_format_arg<_Context>* __data_{nullptr};
+};
+
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___FORMAT_FORMAT_ARGS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/format_context.h b/contrib/libs/cxxsupp/libcxx/include/__format/format_context.h
new file mode 100644
index 00000000000..1cb7ee6a49e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/format_context.h
@@ -0,0 +1,161 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMAT_CONTEXT_H
+#define _LIBCPP___FORMAT_FORMAT_CONTEXT_H
+
+#include <__availability>
+#include <__config>
+#include <__format/format_args.h>
+#include <__format/format_fwd.h>
+#include <__iterator/concepts.h>
+#include <concepts>
+#include <iterator>
+#include <string>
+
+#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#include <locale>
+#include <optional>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+template <class _OutIt, class _CharT>
+requires output_iterator<_OutIt, const _CharT&>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_context;
+
+#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+/**
+ * Helper to create a basic_format_context.
+ *
+ * This is needed since the constructor is private.
+ */
+template <class _OutIt, class _CharT>
+_LIBCPP_HIDE_FROM_ABI basic_format_context<_OutIt, _CharT>
+__format_context_create(
+    _OutIt __out_it,
+    basic_format_args<basic_format_context<_OutIt, _CharT>> __args,
+    optional<_VSTD::locale>&& __loc = nullopt) {
+  return _VSTD::basic_format_context(_VSTD::move(__out_it), __args,
+                                     _VSTD::move(__loc));
+}
+#else
+template <class _OutIt, class _CharT>
+_LIBCPP_HIDE_FROM_ABI basic_format_context<_OutIt, _CharT>
+__format_context_create(
+    _OutIt __out_it,
+    basic_format_args<basic_format_context<_OutIt, _CharT>> __args) {
+  return _VSTD::basic_format_context(_VSTD::move(__out_it), __args);
+}
+#endif
+
+template <class _OutIt, class _CharT>
+requires output_iterator<_OutIt, const _CharT&>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_context {
+public:
+  using iterator = _OutIt;
+  using char_type = _CharT;
+  template <class _Tp>
+  using formatter_type = formatter<_Tp, _CharT>;
+
+  basic_format_context(const basic_format_context&) = delete;
+  basic_format_context& operator=(const basic_format_context&) = delete;
+
+  _LIBCPP_HIDE_FROM_ABI basic_format_arg<basic_format_context>
+  arg(size_t __id) const {
+    return __args_.get(__id);
+  }
+#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+  _LIBCPP_HIDE_FROM_ABI _VSTD::locale locale() {
+    if (!__loc_)
+      __loc_ = _VSTD::locale{};
+    return *__loc_;
+  }
+#endif
+  _LIBCPP_HIDE_FROM_ABI iterator out() { return __out_it_; }
+  _LIBCPP_HIDE_FROM_ABI void advance_to(iterator __it) { __out_it_ = __it; }
+
+private:
+  iterator __out_it_;
+  basic_format_args<basic_format_context> __args_;
+#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+
+  // The Standard doesn't specify how the locale is stored.
+  // [format.context]/6
+  // std::locale locale();
+  //   Returns: The locale passed to the formatting function if the latter
+  //   takes one, and std::locale() otherwise.
+  // This is done by storing the locale of the constructor in this optional. If
+  // locale() is called and the optional has no value the value will be created.
+  // This allows the implementation to lazily create the locale.
+  // TODO FMT Validate whether lazy creation is the best solution.
+  optional<_VSTD::locale> __loc_;
+
+  template <class __OutIt, class __CharT>
+  friend _LIBCPP_HIDE_FROM_ABI basic_format_context<__OutIt, __CharT>
+  _VSTD::__format_context_create(
+      __OutIt, basic_format_args<basic_format_context<__OutIt, __CharT>>,
+      optional<_VSTD::locale>&&);
+
+  // Note: the Standard doesn't specify the required constructors.
+  _LIBCPP_HIDE_FROM_ABI
+  explicit basic_format_context(_OutIt __out_it,
+                                basic_format_args<basic_format_context> __args,
+                                optional<_VSTD::locale>&& __loc)
+      : __out_it_(_VSTD::move(__out_it)), __args_(__args),
+        __loc_(_VSTD::move(__loc)) {}
+#else
+  template <class __OutIt, class __CharT>
+  friend _LIBCPP_HIDE_FROM_ABI basic_format_context<__OutIt, __CharT>
+      _VSTD::__format_context_create(
+          __OutIt, basic_format_args<basic_format_context<__OutIt, __CharT>>);
+
+  _LIBCPP_HIDE_FROM_ABI
+  explicit basic_format_context(_OutIt __out_it,
+                                basic_format_args<basic_format_context> __args)
+      : __out_it_(_VSTD::move(__out_it)), __args_(__args) {}
+#endif
+};
+
+// TODO FMT Implement [format.context]/4
+// [Note 1: For a given type charT, implementations are encouraged to provide a
+// single instantiation of basic_format_context for appending to
+// basic_string<charT>, vector<charT>, or any other container with contiguous
+// storage by wrapping those in temporary objects with a uniform interface
+// (such as a span<charT>) and polymorphic reallocation. - end note]
+
+using format_context = basic_format_context<back_insert_iterator<string>, char>;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+using wformat_context = basic_format_context<back_insert_iterator<wstring>, wchar_t>;
+#endif
+
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___FORMAT_FORMAT_CONTEXT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/format_error.h b/contrib/libs/cxxsupp/libcxx/include/__format/format_error.h
new file mode 100644
index 00000000000..ac1d708030d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/format_error.h
@@ -0,0 +1,51 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMAT_ERROR_H
+#define _LIBCPP___FORMAT_FORMAT_ERROR_H
+
+#include <__config>
+#include <stdexcept>
+
+#ifdef _LIBCPP_NO_EXCEPTIONS
+#include <cstdlib>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+class _LIBCPP_EXCEPTION_ABI format_error : public runtime_error {
+public:
+  _LIBCPP_HIDE_FROM_ABI explicit format_error(const string& __s)
+      : runtime_error(__s) {}
+  _LIBCPP_HIDE_FROM_ABI explicit format_error(const char* __s)
+      : runtime_error(__s) {}
+  virtual ~format_error() noexcept;
+};
+
+_LIBCPP_NORETURN inline _LIBCPP_HIDE_FROM_ABI void
+__throw_format_error(const char* __s) {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+  throw format_error(__s);
+#else
+  (void)__s;
+  _VSTD::abort();
+#endif
+}
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FORMAT_FORMAT_ERROR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/format_fwd.h b/contrib/libs/cxxsupp/libcxx/include/__format/format_fwd.h
new file mode 100644
index 00000000000..7da30aec518
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/format_fwd.h
@@ -0,0 +1,56 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMAT_FWD_H
+#define _LIBCPP___FORMAT_FORMAT_FWD_H
+
+#include <__availability>
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__utility/forward.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+template <class _Context>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_arg;
+
+template <class _Context, class... _Args>
+struct _LIBCPP_TEMPLATE_VIS __format_arg_store;
+
+template <class _Ctx, class... _Args>
+_LIBCPP_HIDE_FROM_ABI __format_arg_store<_Ctx, _Args...>
+make_format_args(const _Args&...);
+
+template <class _Tp, class _CharT = char>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter;
+
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___FORMAT_FORMAT_FWD_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/format_parse_context.h b/contrib/libs/cxxsupp/libcxx/include/__format/format_parse_context.h
new file mode 100644
index 00000000000..59819a92413
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/format_parse_context.h
@@ -0,0 +1,109 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H
+#define _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H
+
+#include <__config>
+#include <__format/format_error.h>
+#include <string_view>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS) && !defined(_LIBCPP_HAS_NO_BUILTIN_IS_CONSTANT_EVALUATED)
+
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_parse_context {
+public:
+  using char_type = _CharT;
+  using const_iterator = typename basic_string_view<_CharT>::const_iterator;
+  using iterator = const_iterator;
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr explicit basic_format_parse_context(basic_string_view<_CharT> __fmt,
+                                                size_t __num_args = 0) noexcept
+      : __begin_(__fmt.begin()),
+        __end_(__fmt.end()),
+        __indexing_(__unknown),
+        __next_arg_id_(0),
+        __num_args_(__num_args) {}
+
+  basic_format_parse_context(const basic_format_parse_context&) = delete;
+  basic_format_parse_context&
+  operator=(const basic_format_parse_context&) = delete;
+
+  _LIBCPP_HIDE_FROM_ABI constexpr const_iterator begin() const noexcept {
+    return __begin_;
+  }
+  _LIBCPP_HIDE_FROM_ABI constexpr const_iterator end() const noexcept {
+    return __end_;
+  }
+  _LIBCPP_HIDE_FROM_ABI constexpr void advance_to(const_iterator __it) {
+    __begin_ = __it;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI constexpr size_t next_arg_id() {
+    if (__indexing_ == __manual)
+      __throw_format_error("Using automatic argument numbering in manual "
+                           "argument numbering mode");
+
+    if (__indexing_ == __unknown)
+      __indexing_ = __automatic;
+    return __next_arg_id_++;
+  }
+  _LIBCPP_HIDE_FROM_ABI constexpr void check_arg_id(size_t __id) {
+    if (__indexing_ == __automatic)
+      __throw_format_error("Using manual argument numbering in automatic "
+                           "argument numbering mode");
+
+    if (__indexing_ == __unknown)
+      __indexing_ = __manual;
+
+    // Throws an exception to make the expression a non core constant
+    // expression as required by:
+    // [format.parse.ctx]/11
+    //   Remarks: Call expressions where id >= num_args_ are not core constant
+    //   expressions ([expr.const]).
+    // Note: the Throws clause [format.parse.ctx]/10 doesn't specify the
+    // behavior when id >= num_args_.
+    if (is_constant_evaluated() && __id >= __num_args_)
+      __throw_format_error("Argument index outside the valid range");
+  }
+
+private:
+  iterator __begin_;
+  iterator __end_;
+  enum _Indexing { __unknown, __manual, __automatic };
+  _Indexing __indexing_;
+  size_t __next_arg_id_;
+  size_t __num_args_;
+};
+
+using format_parse_context = basic_format_parse_context<char>;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+using wformat_parse_context = basic_format_parse_context<wchar_t>;
+#endif
+
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/format_string.h b/contrib/libs/cxxsupp/libcxx/include/__format/format_string.h
new file mode 100644
index 00000000000..885e572fc06
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/format_string.h
@@ -0,0 +1,169 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMAT_STRING_H
+#define _LIBCPP___FORMAT_FORMAT_STRING_H
+
+#include <__config>
+#include <__debug>
+#include <__format/format_error.h>
+#include <cstddef>
+#include <cstdint>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+namespace __format {
+
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS __parse_number_result {
+  const _CharT* __ptr;
+  uint32_t __value;
+};
+
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr __parse_number_result<_CharT>
+__parse_number(const _CharT* __begin, const _CharT* __end);
+
+/**
+ * The maximum value of a numeric argument.
+ *
+ * This is used for:
+ * * arg-id
+ * * width as value or arg-id.
+ * * precision as value or arg-id.
+ *
+ * The value is compatible with the maximum formatting width and precision
+ * using the `%*` syntax on a 32-bit system.
+ */
+inline constexpr uint32_t __number_max = INT32_MAX;
+
+namespace __detail {
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr __parse_number_result<_CharT>
+__parse_zero(const _CharT* __begin, const _CharT*, auto& __parse_ctx) {
+  __parse_ctx.check_arg_id(0);
+  return {++__begin, 0}; // can never be larger than the maximum.
+}
+
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr __parse_number_result<_CharT>
+__parse_automatic(const _CharT* __begin, const _CharT*, auto& __parse_ctx) {
+  size_t __value = __parse_ctx.next_arg_id();
+  _LIBCPP_ASSERT(__value <= __number_max,
+                 "Compilers don't support this number of arguments");
+
+  return {__begin, uint32_t(__value)};
+}
+
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr __parse_number_result<_CharT>
+__parse_manual(const _CharT* __begin, const _CharT* __end, auto& __parse_ctx) {
+  __parse_number_result<_CharT> __r = __parse_number(__begin, __end);
+  __parse_ctx.check_arg_id(__r.__value);
+  return __r;
+}
+
+} // namespace __detail
+
+/**
+ * Parses a number.
+ *
+ * The number is used for the 31-bit values @em width and @em precision. This
+ * allows a maximum value of 2147483647.
+ */
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr __parse_number_result<_CharT>
+__parse_number(const _CharT* __begin, const _CharT* __end_input) {
+  static_assert(__format::__number_max == INT32_MAX,
+                "The algorithm is implemented based on this value.");
+  /*
+   * Limit the input to 9 digits, otherwise we need two checks during every
+   * iteration:
+   * - Are we at the end of the input?
+   * - Does the value exceed width of an uint32_t? (Switching to uint64_t would
+   *   have the same issue, but with a higher maximum.)
+   */
+  const _CharT* __end = __end_input - __begin > 9 ? __begin + 9 : __end_input;
+  uint32_t __value = *__begin - _CharT('0');
+  while (++__begin != __end) {
+    if (*__begin < _CharT('0') || *__begin > _CharT('9'))
+      return {__begin, __value};
+
+    __value = __value * 10 + *__begin - _CharT('0');
+  }
+
+  if (__begin != __end_input && *__begin >= _CharT('0') &&
+      *__begin <= _CharT('9')) {
+
+    /*
+     * There are more than 9 digits, do additional validations:
+     * - Does the 10th digit exceed the maximum allowed value?
+     * - Are there more than 10 digits?
+     * (More than 10 digits always overflows the maximum.)
+     */
+    uint64_t __v = uint64_t(__value) * 10 + *__begin++ - _CharT('0');
+    if (__v > __number_max ||
+        (__begin != __end_input && *__begin >= _CharT('0') &&
+         *__begin <= _CharT('9')))
+      __throw_format_error("The numeric value of the format-spec is too large");
+
+    __value = __v;
+  }
+
+  return {__begin, __value};
+}
+
+/**
+ * Multiplexer for all parse functions.
+ *
+ * The parser will return a pointer beyond the last consumed character. This
+ * should be the closing '}' of the arg-id.
+ */
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr __parse_number_result<_CharT>
+__parse_arg_id(const _CharT* __begin, const _CharT* __end, auto& __parse_ctx) {
+  switch (*__begin) {
+  case _CharT('0'):
+    return __detail::__parse_zero(__begin, __end, __parse_ctx);
+
+  case _CharT(':'):
+    // This case is conditionally valid. It's allowed in an arg-id in the
+    // replacement-field, but not in the std-format-spec. The caller can
+    // provide a better diagnostic, so accept it here unconditionally.
+  case _CharT('}'):
+    return __detail::__parse_automatic(__begin, __end, __parse_ctx);
+  }
+  if (*__begin < _CharT('0') || *__begin > _CharT('9'))
+    __throw_format_error(
+        "The arg-id of the format-spec starts with an invalid character");
+
+  return __detail::__parse_manual(__begin, __end, __parse_ctx);
+}
+
+} // namespace __format
+
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FORMAT_FORMAT_STRING_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/formatter.h b/contrib/libs/cxxsupp/libcxx/include/__format/formatter.h
new file mode 100644
index 00000000000..38fd88e855f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/formatter.h
@@ -0,0 +1,225 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMATTER_H
+#define _LIBCPP___FORMAT_FORMATTER_H
+
+#include <__algorithm/copy.h>
+#include <__algorithm/fill_n.h>
+#include <__availability>
+#include <__config>
+#include <__format/format_error.h>
+#include <__format/format_fwd.h>
+#include <__format/format_string.h>
+#include <__format/parser_std_format_spec.h>
+#include <concepts>
+#include <string_view>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// Currently not implemented specializations throw an exception when used. This
+// does not conform to the Standard. However not all Standard defined formatters
+// have been implemented yet. Until that time the current behavior is intended.
+// TODO FMT Disable the default template.
+template <class _Tp, class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter {
+  _LIBCPP_NORETURN _LIBCPP_HIDE_FROM_ABI auto parse(auto& __parse_ctx)
+      -> decltype(__parse_ctx.begin()) {
+    __throw();
+  }
+
+  _LIBCPP_NORETURN _LIBCPP_HIDE_FROM_ABI auto format(_Tp, auto& __ctx)
+      -> decltype(__ctx.out()) {
+    __throw();
+  }
+
+private:
+  _LIBCPP_NORETURN _LIBCPP_HIDE_FROM_ABI void __throw() {
+    __throw_format_error("Argument type not implemented yet");
+  }
+};
+
+namespace __formatter {
+
+/** The character types that formatters are specialized for. */
+template <class _CharT>
+concept __char_type = same_as<_CharT, char> || same_as<_CharT, wchar_t>;
+
+struct _LIBCPP_TEMPLATE_VIS __padding_size_result {
+  size_t __before;
+  size_t __after;
+};
+
+_LIBCPP_HIDE_FROM_ABI constexpr __padding_size_result
+__padding_size(size_t __size, size_t __width,
+               __format_spec::_Flags::_Alignment __align) {
+  _LIBCPP_ASSERT(__width > __size,
+                 "Don't call this function when no padding is required");
+  _LIBCPP_ASSERT(
+      __align != __format_spec::_Flags::_Alignment::__default,
+      "Caller should adjust the default to the value required by the type");
+
+  size_t __fill = __width - __size;
+  switch (__align) {
+  case __format_spec::_Flags::_Alignment::__default:
+    _LIBCPP_UNREACHABLE();
+
+  case __format_spec::_Flags::_Alignment::__left:
+    return {0, __fill};
+
+  case __format_spec::_Flags::_Alignment::__center: {
+    // The extra padding is divided per [format.string.std]/3
+    // __before = floor(__fill, 2);
+    // __after = ceil(__fill, 2);
+    size_t __before = __fill / 2;
+    size_t __after = __fill - __before;
+    return {__before, __after};
+  }
+  case __format_spec::_Flags::_Alignment::__right:
+    return {__fill, 0};
+  }
+  _LIBCPP_UNREACHABLE();
+}
+
+/**
+ * Writes the input to the output with the required padding.
+ *
+ * Since the output column width is specified the function can be used for
+ * ASCII and Unicode input.
+ *
+ * @pre [@a __first, @a __last) is a valid range.
+ * @pre @a __size <= @a __width. Using this function when this pre-condition
+ *      doesn't hold incurs an unwanted overhead.
+ *
+ * @param __out_it    The output iterator to write to.
+ * @param __first     Pointer to the first element to write.
+ * @param __last      Pointer beyond the last element to write.
+ * @param __size      The (estimated) output column width. When the elements
+ *                    to be written are ASCII the following condition holds
+ *                    @a __size == @a __last - @a __first.
+ * @param __width     The number of output columns to write.
+ * @param __fill      The character used for the alignment of the output.
+ *                    TODO FMT Will probably change to support Unicode grapheme
+ *                    cluster.
+ * @param __alignment The requested alignment.
+ *
+ * @returns           An iterator pointing beyond the last element written.
+ *
+ * @note The type of the elements in range [@a __first, @a __last) can differ
+ * from the type of @a __fill. Integer output uses @c std::to_chars for its
+ * conversion, which means the [@a __first, @a __last) always contains elements
+ * of the type @c char.
+ */
+template <class _CharT, class _Fill>
+_LIBCPP_HIDE_FROM_ABI auto
+__write(output_iterator<const _CharT&> auto __out_it, const _CharT* __first,
+        const _CharT* __last, size_t __size, size_t __width, _Fill __fill,
+        __format_spec::_Flags::_Alignment __alignment) -> decltype(__out_it) {
+
+  _LIBCPP_ASSERT(__first <= __last, "Not a valid range");
+  _LIBCPP_ASSERT(__size < __width, "Precondition failure");
+
+  __padding_size_result __padding =
+      __padding_size(__size, __width, __alignment);
+  __out_it = _VSTD::fill_n(_VSTD::move(__out_it), __padding.__before, __fill);
+  __out_it = _VSTD::copy(__first, __last, _VSTD::move(__out_it));
+  return _VSTD::fill_n(_VSTD::move(__out_it), __padding.__after, __fill);
+}
+
+/**
+ * @overload
+ *
+ * Uses a transformation operation before writing an element.
+ *
+ * TODO FMT Fill will probably change to support Unicode grapheme cluster.
+ */
+template <class _CharT, class _UnaryOperation, class _Fill>
+_LIBCPP_HIDE_FROM_ABI auto
+__write(output_iterator<const _CharT&> auto __out_it, const _CharT* __first,
+        const _CharT* __last, size_t __size, _UnaryOperation __op,
+        size_t __width, _Fill __fill,
+        __format_spec::_Flags::_Alignment __alignment) -> decltype(__out_it) {
+
+  _LIBCPP_ASSERT(__first <= __last, "Not a valid range");
+  _LIBCPP_ASSERT(__size < __width, "Precondition failure");
+
+  __padding_size_result __padding =
+      __padding_size(__size, __width, __alignment);
+  __out_it = _VSTD::fill_n(_VSTD::move(__out_it), __padding.__before, __fill);
+  __out_it = _VSTD::transform(__first, __last, _VSTD::move(__out_it), __op);
+  return _VSTD::fill_n(_VSTD::move(__out_it), __padding.__after, __fill);
+}
+
+/**
+ * Writes Unicode input to the output with the required padding.
+ *
+ * This function does almost the same as the @ref __write function, but handles
+ * the width estimation of the Unicode input.
+ *
+ * @param __str       The range [@a __first, @a __last).
+ * @param __precision The width to truncate the input string to, use @c -1 for
+ *                     no limit.
+ */
+template <class _CharT, class _Fill>
+_LIBCPP_HIDE_FROM_ABI auto
+__write_unicode(output_iterator<const _CharT&> auto __out_it,
+                basic_string_view<_CharT> __str, ptrdiff_t __width,
+                ptrdiff_t __precision, _Fill __fill,
+                __format_spec::_Flags::_Alignment __alignment)
+    -> decltype(__out_it) {
+
+  // This value changes when there Unicode column width limits the output
+  // size.
+  auto __last = __str.end();
+  if (__width != 0 || __precision != -1) {
+    __format_spec::__string_alignment<_CharT> __format_traits =
+        __format_spec::__get_string_alignment(__str.begin(), __str.end(),
+                                              __width, __precision);
+
+    if (__format_traits.__align)
+      return __write(_VSTD::move(__out_it), __str.begin(),
+                     __format_traits.__last, __format_traits.__size, __width,
+                     __fill, __alignment);
+
+    // No alignment required update the output based on the precision.
+    // This might be the same as __str.end().
+    __last = __format_traits.__last;
+  }
+
+  // Copy the input to the output. The output size might be limited by the
+  // precision.
+  return _VSTD::copy(__str.begin(), __last, _VSTD::move(__out_it));
+}
+
+} // namespace __formatter
+
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___FORMAT_FORMATTER_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/formatter_bool.h b/contrib/libs/cxxsupp/libcxx/include/__format/formatter_bool.h
new file mode 100644
index 00000000000..fdd1d75355d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/formatter_bool.h
@@ -0,0 +1,147 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMATTER_BOOL_H
+#define _LIBCPP___FORMAT_FORMATTER_BOOL_H
+
+#include <__availability>
+#include <__config>
+#include <__format/format_error.h>
+#include <__format/format_fwd.h>
+#include <__format/formatter.h>
+#include <__format/formatter_integral.h>
+#include <__format/parser_std_format_spec.h>
+#include <string_view>
+
+#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#include <locale>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+namespace __format_spec {
+
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS __parser_bool : public __parser_integral<_CharT> {
+public:
+  _LIBCPP_HIDE_FROM_ABI constexpr auto parse(auto& __parse_ctx)
+      -> decltype(__parse_ctx.begin()) {
+    auto __it = __parser_integral<_CharT>::__parse(__parse_ctx);
+
+    switch (this->__type) {
+    case _Flags::_Type::__default:
+      this->__type = _Flags::_Type::__string;
+      [[fallthrough]];
+    case _Flags::_Type::__string:
+      this->__handle_bool();
+      break;
+
+    case _Flags::_Type::__char:
+      this->__handle_char();
+      break;
+
+    case _Flags::_Type::__binary_lower_case:
+    case _Flags::_Type::__binary_upper_case:
+    case _Flags::_Type::__octal:
+    case _Flags::_Type::__decimal:
+    case _Flags::_Type::__hexadecimal_lower_case:
+    case _Flags::_Type::__hexadecimal_upper_case:
+      this->__handle_integer();
+      break;
+
+    default:
+      __throw_format_error(
+          "The format-spec type has a type not supported for a bool argument");
+    }
+
+    return __it;
+  }
+};
+
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS __bool_strings;
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS __bool_strings<char> {
+  static constexpr string_view __true{"true"};
+  static constexpr string_view __false{"false"};
+};
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+struct _LIBCPP_TEMPLATE_VIS __bool_strings<wchar_t> {
+  static constexpr wstring_view __true{L"true"};
+  static constexpr wstring_view __false{L"false"};
+};
+#endif
+
+template <class _CharT>
+using __formatter_bool = __formatter_integral<__parser_bool<_CharT>>;
+
+} //namespace __format_spec
+
+// [format.formatter.spec]/2.3
+// For each charT, for each cv-unqualified arithmetic type ArithmeticT other
+// than char, wchar_t, char8_t, char16_t, or char32_t, a specialization
+
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<bool, _CharT>
+    : public __format_spec::__formatter_bool<_CharT> {
+  using _Base = __format_spec::__formatter_bool<_CharT>;
+
+  _LIBCPP_HIDE_FROM_ABI auto format(bool __value, auto& __ctx)
+      -> decltype(__ctx.out()) {
+    if (this->__type != __format_spec::_Flags::_Type::__string)
+      return _Base::format(static_cast<unsigned char>(__value), __ctx);
+
+    if (this->__width_needs_substitution())
+      this->__substitute_width_arg_id(__ctx.arg(this->__width));
+
+#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+    if (this->__locale_specific_form) {
+      const auto& __np = use_facet<numpunct<_CharT>>(__ctx.locale());
+      basic_string<_CharT> __str = __value ? __np.truename() : __np.falsename();
+      return __formatter::__write_unicode(
+          __ctx.out(), basic_string_view<_CharT>{__str}, this->__width, -1,
+          this->__fill, this->__alignment);
+    }
+#endif
+    basic_string_view<_CharT> __str =
+        __value ? __format_spec::__bool_strings<_CharT>::__true
+                : __format_spec::__bool_strings<_CharT>::__false;
+
+    // The output only uses ASCII so every character is one column.
+    unsigned __size = __str.size();
+    if (__size >= this->__width)
+      return _VSTD::copy(__str.begin(), __str.end(), __ctx.out());
+
+    return __formatter::__write(__ctx.out(), __str.begin(), __str.end(), __size,
+                                this->__width, this->__fill, this->__alignment);
+  }
+};
+
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FORMAT_FORMATTER_BOOL_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/formatter_char.h b/contrib/libs/cxxsupp/libcxx/include/__format/formatter_char.h
new file mode 100644
index 00000000000..2131de0778f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/formatter_char.h
@@ -0,0 +1,104 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMATTER_CHAR_H
+#define _LIBCPP___FORMAT_FORMATTER_CHAR_H
+
+#include <__availability>
+#include <__config>
+#include <__format/format_error.h>
+#include <__format/format_fwd.h>
+#include <__format/formatter.h>
+#include <__format/formatter_integral.h>
+#include <__format/parser_std_format_spec.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+namespace __format_spec {
+
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS __parser_char : public __parser_integral<_CharT> {
+public:
+  _LIBCPP_HIDE_FROM_ABI constexpr auto parse(auto& __parse_ctx)
+      -> decltype(__parse_ctx.begin()) {
+    auto __it = __parser_integral<_CharT>::__parse(__parse_ctx);
+
+    switch (this->__type) {
+    case _Flags::_Type::__default:
+      this->__type = _Flags::_Type::__char;
+      [[fallthrough]];
+    case _Flags::_Type::__char:
+      this->__handle_char();
+      break;
+
+    case _Flags::_Type::__binary_lower_case:
+    case _Flags::_Type::__binary_upper_case:
+    case _Flags::_Type::__octal:
+    case _Flags::_Type::__decimal:
+    case _Flags::_Type::__hexadecimal_lower_case:
+    case _Flags::_Type::__hexadecimal_upper_case:
+      this->__handle_integer();
+      break;
+
+    default:
+      __throw_format_error(
+          "The format-spec type has a type not supported for a char argument");
+    }
+
+    return __it;
+  }
+};
+
+template <class _CharT>
+using __formatter_char = __formatter_integral<__parser_char<_CharT>>;
+
+} // namespace __format_spec
+
+// [format.formatter.spec]/2.1 The specializations
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<char, char>
+    : public __format_spec::__formatter_char<char> {};
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<char, wchar_t>
+    : public __format_spec::__formatter_char<wchar_t> {
+  using _Base = __format_spec::__formatter_char<wchar_t>;
+
+  _LIBCPP_HIDE_FROM_ABI auto format(char __value, auto& __ctx)
+      -> decltype(__ctx.out()) {
+    return _Base::format(static_cast<wchar_t>(__value), __ctx);
+  }
+};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<wchar_t, wchar_t>
+    : public __format_spec::__formatter_char<wchar_t> {};
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FORMAT_FORMATTER_CHAR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/formatter_integer.h b/contrib/libs/cxxsupp/libcxx/include/__format/formatter_integer.h
new file mode 100644
index 00000000000..767df36e61e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/formatter_integer.h
@@ -0,0 +1,170 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMATTER_INTEGER_H
+#define _LIBCPP___FORMAT_FORMATTER_INTEGER_H
+
+#include <__availability>
+#include <__config>
+#include <__format/format_error.h>
+#include <__format/format_fwd.h>
+#include <__format/formatter.h>
+#include <__format/formatter_integral.h>
+#include <__format/parser_std_format_spec.h>
+#include <limits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+namespace __format_spec {
+
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS __parser_integer : public __parser_integral<_CharT> {
+public:
+  _LIBCPP_HIDE_FROM_ABI constexpr auto parse(auto& __parse_ctx)
+      -> decltype(__parse_ctx.begin()) {
+    auto __it = __parser_integral<_CharT>::__parse(__parse_ctx);
+
+    switch (this->__type) {
+    case _Flags::_Type::__default:
+      this->__type = _Flags::_Type::__decimal;
+      [[fallthrough]];
+
+    case _Flags::_Type::__binary_lower_case:
+    case _Flags::_Type::__binary_upper_case:
+    case _Flags::_Type::__octal:
+    case _Flags::_Type::__decimal:
+    case _Flags::_Type::__hexadecimal_lower_case:
+    case _Flags::_Type::__hexadecimal_upper_case:
+      this->__handle_integer();
+      break;
+
+    case _Flags::_Type::__char:
+      this->__handle_char();
+      break;
+
+    default:
+      __throw_format_error("The format-spec type has a type not supported for "
+                           "an integer argument");
+    }
+    return __it;
+  }
+};
+
+template <class _CharT>
+using __formatter_integer = __formatter_integral<__parser_integer<_CharT>>;
+
+} // namespace __format_spec
+
+// [format.formatter.spec]/2.3
+// For each charT, for each cv-unqualified arithmetic type ArithmeticT other
+// than char, wchar_t, char8_t, char16_t, or char32_t, a specialization
+
+// Signed integral types.
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<signed char, _CharT>
+    : public __format_spec::__formatter_integer<_CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<short, _CharT>
+    : public __format_spec::__formatter_integer<_CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<int, _CharT>
+    : public __format_spec::__formatter_integer<_CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<long, _CharT>
+    : public __format_spec::__formatter_integer<_CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<long long, _CharT>
+    : public __format_spec::__formatter_integer<_CharT> {};
+#ifndef _LIBCPP_HAS_NO_INT128
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<__int128_t, _CharT>
+    : public __format_spec::__formatter_integer<_CharT> {
+  using _Base = __format_spec::__formatter_integer<_CharT>;
+
+  _LIBCPP_HIDE_FROM_ABI auto format(__int128_t __value, auto& __ctx)
+      -> decltype(__ctx.out()) {
+    // TODO FMT Implement full 128 bit support.
+    using _To = long long;
+    if (__value < numeric_limits<_To>::min() ||
+        __value > numeric_limits<_To>::max())
+      __throw_format_error("128-bit value is outside of implemented range");
+
+    return _Base::format(static_cast<_To>(__value), __ctx);
+  }
+};
+#endif
+
+// Unsigned integral types.
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<unsigned char, _CharT>
+    : public __format_spec::__formatter_integer<_CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<unsigned short, _CharT>
+    : public __format_spec::__formatter_integer<_CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<unsigned, _CharT>
+    : public __format_spec::__formatter_integer<_CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<unsigned long, _CharT>
+    : public __format_spec::__formatter_integer<_CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<unsigned long long, _CharT>
+    : public __format_spec::__formatter_integer<_CharT> {};
+#ifndef _LIBCPP_HAS_NO_INT128
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<__uint128_t, _CharT>
+    : public __format_spec::__formatter_integer<_CharT> {
+  using _Base = __format_spec::__formatter_integer<_CharT>;
+
+  _LIBCPP_HIDE_FROM_ABI auto format(__uint128_t __value, auto& __ctx)
+      -> decltype(__ctx.out()) {
+    // TODO FMT Implement full 128 bit support.
+    using _To = unsigned long long;
+    if (__value < numeric_limits<_To>::min() ||
+        __value > numeric_limits<_To>::max())
+      __throw_format_error("128-bit value is outside of implemented range");
+
+    return _Base::format(static_cast<_To>(__value), __ctx);
+  }
+};
+#endif
+
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___FORMAT_FORMATTER_INTEGER_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/formatter_integral.h b/contrib/libs/cxxsupp/libcxx/include/__format/formatter_integral.h
new file mode 100644
index 00000000000..14b4e3a8273
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/formatter_integral.h
@@ -0,0 +1,502 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMATTER_INTEGRAL_H
+#define _LIBCPP___FORMAT_FORMATTER_INTEGRAL_H
+
+#include <__config>
+#include <__format/format_error.h>
+#include <__format/format_fwd.h>
+#include <__format/formatter.h>
+#include <__format/parser_std_format_spec.h>
+#include <__algorithm/copy.h>
+#include <__algorithm/copy_n.h>
+#include <__algorithm/fill_n.h>
+#include <__algorithm/transform.h>
+#include <array>
+#include <charconv>
+#include <concepts>
+#include <limits>
+#include <string>
+
+#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#include <locale>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+/**
+ * Integral formatting classes.
+ *
+ * There are two types used here:
+ * * C++-type, the type as used in C++.
+ * * format-type, the output type specified in the std-format-spec.
+ *
+ * Design of the integral formatters consists of several layers.
+ * * @ref __parser_integral The basic std-format-spec parser for all integral
+ *   classes. This parser does the basic sanity checks. It also contains some
+ *   helper functions that are nice to have available for all parsers.
+ * * A C++-type specific parser. These parsers must derive from
+ *   @ref __parser_integral. Their task is to validate whether the parsed
+ *   std-format-spec is valid for the C++-type and selected format-type. After
+ *   validation they need to make sure all members are properly set. For
+ *   example, when the alignment hasn't changed it needs to set the proper
+ *   default alignment for the format-type. The following parsers are available:
+ *   - @ref __parser_integer
+ *   - @ref __parser_char
+ *   - @ref __parser_bool
+ * * A general formatter for all integral types @ref __formatter_integral. This
+ *   formatter can handle all formatting of integers and characters. The class
+ *   derives from the proper formatter.
+ *   Note the boolean string format-type isn't supported in this class.
+ * * A typedef C++-type group combining the @ref __formatter_integral with a
+ *   parser:
+ *   * @ref __formatter_integer
+ *   * @ref __formatter_char
+ *   * @ref __formatter_bool
+ * * Then every C++-type has its own formatter specializations. They inherit
+ *   from the C++-type group typedef. Most specializations need nothing else.
+ *   Others need some additional specializations in this class.
+ */
+namespace __format_spec {
+
+/** Wrapper around @ref to_chars, returning the output pointer. */
+template <class _Tp>
+_LIBCPP_HIDE_FROM_ABI char* __to_buffer(char* __first, char* __last,
+                                        _Tp __value, int __base) {
+  // TODO FMT Evaluate code overhead due to not calling the internal function
+  // directly. (Should be zero overhead.)
+  to_chars_result __r = _VSTD::to_chars(__first, __last, __value, __base);
+  _LIBCPP_ASSERT(__r.ec == errc(0), "Internal buffer too small");
+  return __r.ptr;
+}
+
+/**
+ * Helper to determine the buffer size to output a integer in Base @em x.
+ *
+ * There are several overloads for the supported bases. The function uses the
+ * base as template argument so it can be used in a constant expression.
+ */
+template <unsigned_integral _Tp, size_t _Base>
+_LIBCPP_HIDE_FROM_ABI constexpr size_t __buffer_size() noexcept
+    requires(_Base == 2) {
+  return numeric_limits<_Tp>::digits // The number of binary digits.
+         + 2                         // Reserve space for the '0[Bb]' prefix.
+         + 1;                        // Reserve space for the sign.
+}
+
+template <unsigned_integral _Tp, size_t _Base>
+_LIBCPP_HIDE_FROM_ABI constexpr size_t __buffer_size() noexcept
+    requires(_Base == 8) {
+  return numeric_limits<_Tp>::digits // The number of binary digits.
+             / 3                     // Adjust to octal.
+         + 1                         // Turn floor to ceil.
+         + 1                         // Reserve space for the '0' prefix.
+         + 1;                        // Reserve space for the sign.
+}
+
+template <unsigned_integral _Tp, size_t _Base>
+_LIBCPP_HIDE_FROM_ABI constexpr size_t __buffer_size() noexcept
+    requires(_Base == 10) {
+  return numeric_limits<_Tp>::digits10 // The floored value.
+         + 1                           // Turn floor to ceil.
+         + 1;                          // Reserve space for the sign.
+}
+
+template <unsigned_integral _Tp, size_t _Base>
+_LIBCPP_HIDE_FROM_ABI constexpr size_t __buffer_size() noexcept
+    requires(_Base == 16) {
+  return numeric_limits<_Tp>::digits // The number of binary digits.
+             / 4                     // Adjust to hexadecimal.
+         + 2                         // Reserve space for the '0[Xx]' prefix.
+         + 1;                        // Reserve space for the sign.
+}
+
+_LIBCPP_HIDE_FROM_ABI inline char* __insert_sign(char* __buf, bool __negative,
+                                                 _Flags::_Sign __sign) {
+  if (__negative)
+    *__buf++ = '-';
+  else
+    switch (__sign) {
+    case _Flags::_Sign::__default:
+    case _Flags::_Sign::__minus:
+      // No sign added.
+      break;
+    case _Flags::_Sign::__plus:
+      *__buf++ = '+';
+      break;
+    case _Flags::_Sign::__space:
+      *__buf++ = ' ';
+      break;
+    }
+
+  return __buf;
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr char __hex_to_upper(char c) {
+  switch (c) {
+  case 'a':
+    return 'A';
+  case 'b':
+    return 'B';
+  case 'c':
+    return 'C';
+  case 'd':
+    return 'D';
+  case 'e':
+    return 'E';
+  case 'f':
+    return 'F';
+  }
+  return c;
+}
+
+/**
+ * Determines the required grouping based on the size of the input.
+ *
+ * The grouping's last element will be repeated. For simplicity this repeating
+ * is unwrapped based on the length of the input. (When the input is short some
+ * groups are not processed.)
+ *
+ * @returns The size of the groups to write. This means the number of
+ * separator characters written is size() - 1.
+ *
+ * @note Since zero-sized groups cause issues they are silently ignored.
+ *
+ * @note The grouping field of the locale is always a @c std::string,
+ * regardless whether the @c std::numpunct's type is @c char or @c wchar_t.
+ */
+_LIBCPP_HIDE_FROM_ABI inline string
+__determine_grouping(ptrdiff_t __size, const string& __grouping) {
+  _LIBCPP_ASSERT(!__grouping.empty() && __size > __grouping[0],
+                 "The slow grouping formatting is used while there will be no "
+                 "separators written");
+  string __r;
+  auto __end = __grouping.end() - 1;
+  auto __ptr = __grouping.begin();
+
+  while (true) {
+    __size -= *__ptr;
+    if (__size > 0)
+      __r.push_back(*__ptr);
+    else {
+      // __size <= 0 so the value pushed will be <= *__ptr.
+      __r.push_back(*__ptr + __size);
+      return __r;
+    }
+
+    // Proceed to the next group.
+    if (__ptr != __end) {
+      do {
+        ++__ptr;
+        // Skip grouping with a width of 0.
+      } while (*__ptr == 0 && __ptr != __end);
+    }
+  }
+
+  _LIBCPP_UNREACHABLE();
+}
+
+template <class _Parser>
+requires __formatter::__char_type<typename _Parser::char_type>
+class _LIBCPP_TEMPLATE_VIS __formatter_integral : public _Parser {
+public:
+  using _CharT = typename _Parser::char_type;
+
+  template <integral _Tp>
+  _LIBCPP_HIDE_FROM_ABI auto format(_Tp __value, auto& __ctx)
+      -> decltype(__ctx.out()) {
+    if (this->__width_needs_substitution())
+      this->__substitute_width_arg_id(__ctx.arg(this->__width));
+
+    if (this->__type == _Flags::_Type::__char)
+      return __format_as_char(__value, __ctx);
+
+    if constexpr (unsigned_integral<_Tp>)
+      return __format_unsigned_integral(__value, false, __ctx);
+    else {
+      // Depending on the std-format-spec string the sign and the value
+      // might not be outputted together:
+      // - alternate form may insert a prefix string.
+      // - zero-padding may insert additional '0' characters.
+      // Therefore the value is processed as a positive unsigned value.
+      // The function @ref __insert_sign will a '-' when the value was negative.
+      auto __r = __to_unsigned_like(__value);
+      bool __negative = __value < 0;
+      if (__negative)
+        __r = __complement(__r);
+
+      return __format_unsigned_integral(__r, __negative, __ctx);
+    }
+  }
+
+private:
+  /** Generic formatting for format-type c. */
+  _LIBCPP_HIDE_FROM_ABI auto __format_as_char(integral auto __value,
+                                              auto& __ctx)
+      -> decltype(__ctx.out()) {
+    if (this->__alignment == _Flags::_Alignment::__default)
+      this->__alignment = _Flags::_Alignment::__right;
+
+    using _Tp = decltype(__value);
+    if constexpr (!same_as<_CharT, _Tp>) {
+      // cmp_less and cmp_greater can't be used for character types.
+      if constexpr (signed_integral<_CharT> == signed_integral<_Tp>) {
+        if (__value < numeric_limits<_CharT>::min() ||
+            __value > numeric_limits<_CharT>::max())
+          __throw_format_error(
+              "Integral value outside the range of the char type");
+      } else if constexpr (signed_integral<_CharT>) {
+        // _CharT is signed _Tp is unsigned
+        if (__value >
+            static_cast<make_unsigned_t<_CharT>>(numeric_limits<_CharT>::max()))
+          __throw_format_error(
+              "Integral value outside the range of the char type");
+      } else {
+        // _CharT is unsigned _Tp is signed
+        if (__value < 0 || static_cast<make_unsigned_t<_Tp>>(__value) >
+                               numeric_limits<_CharT>::max())
+          __throw_format_error(
+              "Integral value outside the range of the char type");
+      }
+    }
+
+    const auto __c = static_cast<_CharT>(__value);
+    return __write(_VSTD::addressof(__c), _VSTD::addressof(__c) + 1,
+                   __ctx.out());
+  }
+
+  /**
+   * Generic formatting for format-type bBdoxX.
+   *
+   * This small wrapper allocates a buffer with the required size. Then calls
+   * the real formatter with the buffer and the prefix for the base.
+   */
+  _LIBCPP_HIDE_FROM_ABI auto
+  __format_unsigned_integral(unsigned_integral auto __value, bool __negative,
+                             auto& __ctx) -> decltype(__ctx.out()) {
+    switch (this->__type) {
+    case _Flags::_Type::__binary_lower_case: {
+      array<char, __buffer_size<decltype(__value), 2>()> __array;
+      return __format_unsigned_integral(__array.begin(), __array.end(), __value,
+                                        __negative, 2, __ctx, "0b");
+    }
+    case _Flags::_Type::__binary_upper_case: {
+      array<char, __buffer_size<decltype(__value), 2>()> __array;
+      return __format_unsigned_integral(__array.begin(), __array.end(), __value,
+                                        __negative, 2, __ctx, "0B");
+    }
+    case _Flags::_Type::__octal: {
+      // Octal is special; if __value == 0 there's no prefix.
+      array<char, __buffer_size<decltype(__value), 8>()> __array;
+      return __format_unsigned_integral(__array.begin(), __array.end(), __value,
+                                        __negative, 8, __ctx,
+                                        __value != 0 ? "0" : nullptr);
+    }
+    case _Flags::_Type::__decimal: {
+      array<char, __buffer_size<decltype(__value), 10>()> __array;
+      return __format_unsigned_integral(__array.begin(), __array.end(), __value,
+                                        __negative, 10, __ctx, nullptr);
+    }
+    case _Flags::_Type::__hexadecimal_lower_case: {
+      array<char, __buffer_size<decltype(__value), 16>()> __array;
+      return __format_unsigned_integral(__array.begin(), __array.end(), __value,
+                                        __negative, 16, __ctx, "0x");
+    }
+    case _Flags::_Type::__hexadecimal_upper_case: {
+      array<char, __buffer_size<decltype(__value), 16>()> __array;
+      return __format_unsigned_integral(__array.begin(), __array.end(), __value,
+                                        __negative, 16, __ctx, "0X");
+    }
+    default:
+      _LIBCPP_ASSERT(false, "The parser should have validated the type");
+      _LIBCPP_UNREACHABLE();
+    }
+  }
+
+  template <class _Tp>
+  requires(same_as<char, _Tp> || same_as<wchar_t, _Tp>) _LIBCPP_HIDE_FROM_ABI
+      auto __write(const _Tp* __first, const _Tp* __last, auto __out_it)
+          -> decltype(__out_it) {
+
+    unsigned __size = __last - __first;
+    if (this->__type != _Flags::_Type::__hexadecimal_upper_case) [[likely]] {
+      if (__size >= this->__width)
+        return _VSTD::copy(__first, __last, _VSTD::move(__out_it));
+
+      return __formatter::__write(_VSTD::move(__out_it), __first, __last,
+                                  __size, this->__width, this->__fill,
+                                  this->__alignment);
+    }
+
+    // this->__type == _Flags::_Type::__hexadecimal_upper_case
+    // This means all characters in the range [a-f] need to be changed to their
+    // uppercase representation. The transformation is done as transformation
+    // in the output routine instead of before. This avoids another pass over
+    // the data.
+    // TODO FMT See whether it's possible to do this transformation during the
+    // conversion. (This probably requires changing std::to_chars' alphabet.)
+    if (__size >= this->__width)
+      return _VSTD::transform(__first, __last, _VSTD::move(__out_it),
+                              __hex_to_upper);
+
+    return __formatter::__write(_VSTD::move(__out_it), __first, __last, __size,
+                                __hex_to_upper, this->__width, this->__fill,
+                                this->__alignment);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI auto
+  __format_unsigned_integral(char* __begin, char* __end,
+                             unsigned_integral auto __value, bool __negative,
+                             int __base, auto& __ctx, const char* __prefix)
+      -> decltype(__ctx.out()) {
+    char* __first = __insert_sign(__begin, __negative, this->__sign);
+    if (this->__alternate_form && __prefix)
+      while (*__prefix)
+        *__first++ = *__prefix++;
+
+    char* __last = __to_buffer(__first, __end, __value, __base);
+#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+    if (this->__locale_specific_form) {
+      const auto& __np = use_facet<numpunct<_CharT>>(__ctx.locale());
+      string __grouping = __np.grouping();
+      ptrdiff_t __size = __last - __first;
+      // Writing the grouped form has more overhead than the normal output
+      // routines. If there will be no separators written the locale-specific
+      // form is identical to the normal routine. Test whether to grouped form
+      // is required.
+      if (!__grouping.empty() && __size > __grouping[0])
+        return __format_grouping(__ctx.out(), __begin, __first, __last,
+                                 __determine_grouping(__size, __grouping),
+                                 __np.thousands_sep());
+    }
+#endif
+    auto __out_it = __ctx.out();
+    if (this->__alignment != _Flags::_Alignment::__default)
+      __first = __begin;
+    else {
+      // __buf contains [sign][prefix]data
+      //                              ^ location of __first
+      // The zero padding is done like:
+      // - Write [sign][prefix]
+      // - Write data right aligned with '0' as fill character.
+      __out_it = _VSTD::copy(__begin, __first, _VSTD::move(__out_it));
+      this->__alignment = _Flags::_Alignment::__right;
+      this->__fill = _CharT('0');
+      unsigned __size = __first - __begin;
+      this->__width -= _VSTD::min(__size, this->__width);
+    }
+
+    return __write(__first, __last, _VSTD::move(__out_it));
+  }
+
+#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+  /** Format's the locale-specific form's groupings. */
+  template <class _OutIt, class _CharT>
+  _LIBCPP_HIDE_FROM_ABI _OutIt
+  __format_grouping(_OutIt __out_it, const char* __begin, const char* __first,
+                    const char* __last, string&& __grouping, _CharT __sep) {
+
+    // TODO FMT This function duplicates some functionality of the normal
+    // output routines. Evaluate whether these parts can be efficiently
+    // combined with the existing routines.
+
+    unsigned __size = (__first - __begin) +    // [sign][prefix]
+                      (__last - __first) +     // data
+                      (__grouping.size() - 1); // number of separator characters
+
+    __formatter::__padding_size_result __padding = {0, 0};
+    if (this->__alignment == _Flags::_Alignment::__default) {
+      // Write [sign][prefix].
+      __out_it = _VSTD::copy(__begin, __first, _VSTD::move(__out_it));
+
+      if (this->__width > __size) {
+        // Write zero padding.
+        __padding.__before = this->__width - __size;
+        __out_it = _VSTD::fill_n(_VSTD::move(__out_it), this->__width - __size,
+                                 _CharT('0'));
+      }
+    } else {
+      if (this->__width > __size) {
+        // Determine padding and write padding.
+        __padding = __formatter::__padding_size(__size, this->__width,
+                                                this->__alignment);
+
+        __out_it = _VSTD::fill_n(_VSTD::move(__out_it), __padding.__before,
+                                 this->__fill);
+      }
+      // Write [sign][prefix].
+      __out_it = _VSTD::copy(__begin, __first, _VSTD::move(__out_it));
+    }
+
+    auto __r = __grouping.rbegin();
+    auto __e = __grouping.rend() - 1;
+    _LIBCPP_ASSERT(__r != __e, "The slow grouping formatting is used while "
+                               "there will be no separators written.");
+    // The output is divided in small groups of numbers to write:
+    // - A group before the first separator.
+    // - A separator and a group, repeated for the number of separators.
+    // - A group after the last separator.
+    // This loop achieves that process by testing the termination condition
+    // midway in the loop.
+    //
+    // TODO FMT This loop evaluates the loop invariant `this->__type !=
+    // _Flags::_Type::__hexadecimal_upper_case` for every iteration. (This test
+    // happens in the __write call.) Benchmark whether making two loops and
+    // hoisting the invariant is worth the effort.
+    while (true) {
+      if (this->__type == _Flags::_Type::__hexadecimal_upper_case) {
+        __last = __first + *__r;
+        __out_it = _VSTD::transform(__first, __last, _VSTD::move(__out_it),
+                                    __hex_to_upper);
+        __first = __last;
+      } else {
+        __out_it = _VSTD::copy_n(__first, *__r, _VSTD::move(__out_it));
+        __first += *__r;
+      }
+
+      if (__r == __e)
+        break;
+
+      ++__r;
+      *__out_it++ = __sep;
+    }
+
+    return _VSTD::fill_n(_VSTD::move(__out_it), __padding.__after,
+                         this->__fill);
+  }
+#endif // _LIBCPP_HAS_NO_LOCALIZATION
+};
+
+} // namespace __format_spec
+
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___FORMAT_FORMATTER_INTEGRAL_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/formatter_string.h b/contrib/libs/cxxsupp/libcxx/include/__format/formatter_string.h
new file mode 100644
index 00000000000..45d1147e445
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/formatter_string.h
@@ -0,0 +1,154 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_FORMATTER_STRING_H
+#define _LIBCPP___FORMAT_FORMATTER_STRING_H
+
+#include <__config>
+#include <__format/format_error.h>
+#include <__format/format_fwd.h>
+#include <__format/format_string.h>
+#include <__format/formatter.h>
+#include <__format/parser_std_format_spec.h>
+#include <algorithm>
+#include <string_view>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+namespace __format_spec {
+
+template <__formatter::__char_type _CharT>
+class _LIBCPP_TEMPLATE_VIS __formatter_string : public __parser_string<_CharT> {
+public:
+  _LIBCPP_HIDE_FROM_ABI auto format(basic_string_view<_CharT> __str,
+                                    auto& __ctx) -> decltype(__ctx.out()) {
+
+    _LIBCPP_ASSERT(this->__alignment != _Flags::_Alignment::__default,
+                   "The parser should not use these defaults");
+
+    if (this->__width_needs_substitution())
+      this->__substitute_width_arg_id(__ctx.arg(this->__width));
+
+    if (this->__precision_needs_substitution())
+      this->__substitute_precision_arg_id(__ctx.arg(this->__precision));
+
+    return __formatter::__write_unicode(
+        __ctx.out(), __str, this->__width,
+        this->__has_precision_field() ? this->__precision : -1, this->__fill,
+        this->__alignment);
+  }
+};
+
+} //namespace __format_spec
+
+// [format.formatter.spec]/2.2 For each charT, the string type specializations
+
+// Formatter const char*.
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<const _CharT*, _CharT>
+    : public __format_spec::__formatter_string<_CharT> {
+  using _Base = __format_spec::__formatter_string<_CharT>;
+
+  _LIBCPP_HIDE_FROM_ABI auto format(const _CharT* __str, auto& __ctx)
+      -> decltype(__ctx.out()) {
+    _LIBCPP_ASSERT(__str, "The basic_format_arg constructor should have "
+                          "prevented an invalid pointer.");
+
+    // When using a center or right alignment and the width option the length
+    // of __str must be known to add the padding upfront. This case is handled
+    // by the base class by converting the argument to a basic_string_view.
+    //
+    // When using left alignment and the width option the padding is added
+    // after outputting __str so the length can be determined while outputting
+    // __str. The same holds true for the precision, during outputting __str it
+    // can be validated whether the precision threshold has been reached. For
+    // now these optimizations aren't implemented. Instead the base class
+    // handles these options.
+    // TODO FMT Implement these improvements.
+    if (this->__has_width_field() || this->__has_precision_field())
+      return _Base::format(__str, __ctx);
+
+    // No formatting required, copy the string to the output.
+    auto __out_it = __ctx.out();
+    while (*__str)
+      *__out_it++ = *__str++;
+    return __out_it;
+  }
+};
+
+// Formatter char*.
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<_CharT*, _CharT> : public formatter<const _CharT*, _CharT> {
+  using _Base = formatter<const _CharT*, _CharT>;
+
+  _LIBCPP_HIDE_FROM_ABI auto format(_CharT* __str, auto& __ctx)
+      -> decltype(__ctx.out()) {
+    return _Base::format(__str, __ctx);
+  }
+};
+
+// Formatter const char[].
+template <class _CharT, size_t _Size>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<const _CharT[_Size], _CharT>
+    : public __format_spec::__formatter_string<_CharT> {
+  using _Base = __format_spec::__formatter_string<_CharT>;
+
+  _LIBCPP_HIDE_FROM_ABI auto format(const _CharT __str[_Size], auto& __ctx)
+      -> decltype(__ctx.out()) {
+    return _Base::format(_VSTD::basic_string_view<_CharT>(__str, _Size), __ctx);
+  }
+};
+
+// Formatter std::string.
+template <class _CharT, class _Traits, class _Allocator>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<basic_string<_CharT, _Traits, _Allocator>, _CharT>
+    : public __format_spec::__formatter_string<_CharT> {
+  using _Base = __format_spec::__formatter_string<_CharT>;
+
+  _LIBCPP_HIDE_FROM_ABI auto
+  format(const basic_string<_CharT, _Traits, _Allocator>& __str, auto& __ctx)
+      -> decltype(__ctx.out()) {
+    return _Base::format(_VSTD::basic_string_view<_CharT>(__str), __ctx);
+  }
+};
+
+// Formatter std::string_view.
+template <class _CharT, class _Traits>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<basic_string_view<_CharT, _Traits>, _CharT>
+    : public __format_spec::__formatter_string<_CharT> {};
+
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___FORMAT_FORMATTER_STRING_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__format/parser_std_format_spec.h b/contrib/libs/cxxsupp/libcxx/include/__format/parser_std_format_spec.h
new file mode 100644
index 00000000000..77ee380936c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__format/parser_std_format_spec.h
@@ -0,0 +1,1184 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FORMAT_PARSER_STD_FORMAT_SPEC_H
+#define _LIBCPP___FORMAT_PARSER_STD_FORMAT_SPEC_H
+
+#include <__algorithm/find_if.h>
+#include <__algorithm/min.h>
+#include <__config>
+#include <__debug>
+#include <__format/format_arg.h>
+#include <__format/format_error.h>
+#include <__format/format_string.h>
+#include <__variant/monostate.h>
+#include <bit>
+#include <concepts>
+#include <cstdint>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+# pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+# if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+namespace __format_spec {
+
+/**
+ * Contains the flags for the std-format-spec.
+ *
+ * Some format-options can only be used for specific C++types and may depend on
+ * the selected format-type.
+ * * The C++type filtering can be done using the proper policies for
+ *   @ref __parser_std.
+ * * The format-type filtering needs to be done post parsing in the parser
+ *   derived from @ref __parser_std.
+ */
+class _LIBCPP_TYPE_VIS _Flags {
+public:
+  enum class _LIBCPP_ENUM_VIS _Alignment : uint8_t {
+    /**
+     * No alignment is set in the format string.
+     *
+     * Zero-padding is ignored when an alignment is selected.
+     * The default alignment depends on the selected format-type.
+     */
+    __default,
+    __left,
+    __center,
+    __right
+  };
+  enum class _LIBCPP_ENUM_VIS _Sign : uint8_t {
+    /**
+     * No sign is set in the format string.
+     *
+     * The sign isn't allowed for certain format-types. By using this value
+     * it's possible to detect whether or not the user explicitly set the sign
+     * flag. For formatting purposes it behaves the same as @ref __minus.
+     */
+    __default,
+    __minus,
+    __plus,
+    __space
+  };
+
+  _Alignment __alignment : 2 {_Alignment::__default};
+  _Sign __sign : 2 {_Sign::__default};
+  uint8_t __alternate_form : 1 {false};
+  uint8_t __zero_padding : 1 {false};
+  uint8_t __locale_specific_form : 1 {false};
+
+  enum class _LIBCPP_ENUM_VIS _Type : uint8_t {
+    __default,
+    __string,
+    __binary_lower_case,
+    __binary_upper_case,
+    __octal,
+    __decimal,
+    __hexadecimal_lower_case,
+    __hexadecimal_upper_case,
+    __pointer,
+    __char,
+    __float_hexadecimal_lower_case,
+    __float_hexadecimal_upper_case,
+    __scientific_lower_case,
+    __scientific_upper_case,
+    __fixed_lower_case,
+    __fixed_upper_case,
+    __general_lower_case,
+    __general_upper_case
+  };
+
+  _Type __type{_Type::__default};
+};
+
+namespace __detail {
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr bool
+__parse_alignment(_CharT __c, _Flags& __flags) noexcept {
+  switch (__c) {
+  case _CharT('<'):
+    __flags.__alignment = _Flags::_Alignment::__left;
+    return true;
+
+  case _CharT('^'):
+    __flags.__alignment = _Flags::_Alignment::__center;
+    return true;
+
+  case _CharT('>'):
+    __flags.__alignment = _Flags::_Alignment::__right;
+    return true;
+  }
+  return false;
+}
+} // namespace __detail
+
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS __parser_fill_align {
+public:
+  // TODO FMT The standard doesn't specify this character is a Unicode
+  // character. Validate what fmt and MSVC have implemented.
+  _CharT __fill{_CharT(' ')};
+
+protected:
+  _LIBCPP_HIDE_FROM_ABI constexpr const _CharT*
+  __parse(const _CharT* __begin, const _CharT* __end, _Flags& __flags) {
+    _LIBCPP_ASSERT(__begin != __end,
+                   "When called with an empty input the function will cause "
+                   "undefined behavior by evaluating data not in the input");
+    if (__begin + 1 != __end) {
+      if (__detail::__parse_alignment(*(__begin + 1), __flags)) {
+        if (*__begin == _CharT('{') || *__begin == _CharT('}'))
+          __throw_format_error(
+              "The format-spec fill field contains an invalid character");
+        __fill = *__begin;
+        return __begin + 2;
+      }
+    }
+
+    if (__detail::__parse_alignment(*__begin, __flags))
+      return __begin + 1;
+
+    return __begin;
+  }
+};
+
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr const _CharT*
+__parse_sign(const _CharT* __begin, _Flags& __flags) noexcept {
+  switch (*__begin) {
+  case _CharT('-'):
+    __flags.__sign = _Flags::_Sign::__minus;
+    break;
+  case _CharT('+'):
+    __flags.__sign = _Flags::_Sign::__plus;
+    break;
+  case _CharT(' '):
+    __flags.__sign = _Flags::_Sign::__space;
+    break;
+  default:
+    return __begin;
+  }
+  return __begin + 1;
+}
+
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr const _CharT*
+__parse_alternate_form(const _CharT* __begin, _Flags& __flags) noexcept {
+  if (*__begin == _CharT('#')) {
+    __flags.__alternate_form = true;
+    ++__begin;
+  }
+
+  return __begin;
+}
+
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr const _CharT*
+__parse_zero_padding(const _CharT* __begin, _Flags& __flags) noexcept {
+  if (*__begin == _CharT('0')) {
+    __flags.__zero_padding = true;
+    ++__begin;
+  }
+
+  return __begin;
+}
+
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr __format::__parse_number_result< _CharT>
+__parse_arg_id(const _CharT* __begin, const _CharT* __end, auto& __parse_ctx) {
+  // This function is a wrapper to call the real parser. But it does the
+  // validation for the pre-conditions and post-conditions.
+  if (__begin == __end)
+    __throw_format_error("End of input while parsing format-spec arg-id");
+
+  __format::__parse_number_result __r =
+      __format::__parse_arg_id(__begin, __end, __parse_ctx);
+
+  if (__r.__ptr == __end || *__r.__ptr != _CharT('}'))
+    __throw_format_error("A format-spec arg-id should terminate at a '}'");
+
+  ++__r.__ptr;
+  return __r;
+}
+
+template <class _Context>
+_LIBCPP_HIDE_FROM_ABI constexpr uint32_t
+__substitute_arg_id(basic_format_arg<_Context> __arg) {
+  return visit_format_arg(
+      [](auto __arg) -> uint32_t {
+        using _Type = decltype(__arg);
+        if constexpr (integral<_Type>) {
+          if constexpr (signed_integral<_Type>) {
+            if (__arg < 0)
+              __throw_format_error("A format-spec arg-id replacement shouldn't "
+                                   "have a negative value");
+          }
+
+          using _CT = common_type_t<_Type, decltype(__format::__number_max)>;
+          if (static_cast<_CT>(__arg) >
+              static_cast<_CT>(__format::__number_max))
+            __throw_format_error("A format-spec arg-id replacement exceeds "
+                                 "the maximum supported value");
+
+          return __arg;
+        } else if constexpr (same_as<_Type, monostate>)
+          __throw_format_error("Argument index out of bounds");
+        else
+          __throw_format_error("A format-spec arg-id replacement argument "
+                               "isn't an integral type");
+      },
+      __arg);
+}
+
+class _LIBCPP_TYPE_VIS __parser_width {
+public:
+  /** Contains a width or an arg-id. */
+  uint32_t __width : 31 {0};
+  /** Determines whether the value stored is a width or an arg-id. */
+  uint32_t __width_as_arg : 1 {0};
+
+protected:
+  /**
+   * Does the supplied std-format-spec contain a width field?
+   *
+   * When the field isn't present there's no padding required. This can be used
+   * to optimize the formatting.
+   */
+  constexpr bool __has_width_field() const noexcept {
+    return __width_as_arg || __width;
+  }
+
+  /**
+   * Does the supplied width field contain an arg-id?
+   *
+   * If @c true the formatter needs to call @ref __substitute_width_arg_id.
+   */
+  constexpr bool __width_needs_substitution() const noexcept {
+    return __width_as_arg;
+  }
+
+  template <class _CharT>
+  _LIBCPP_HIDE_FROM_ABI constexpr const _CharT*
+  __parse(const _CharT* __begin, const _CharT* __end, auto& __parse_ctx) {
+    if (*__begin == _CharT('0'))
+      __throw_format_error(
+          "A format-spec width field shouldn't have a leading zero");
+
+    if (*__begin == _CharT('{')) {
+      __format::__parse_number_result __r =
+          __parse_arg_id(++__begin, __end, __parse_ctx);
+      __width = __r.__value;
+      __width_as_arg = 1;
+      return __r.__ptr;
+    }
+
+    if (*__begin < _CharT('0') || *__begin > _CharT('9'))
+      return __begin;
+
+    __format::__parse_number_result __r =
+        __format::__parse_number(__begin, __end);
+    __width = __r.__value;
+    _LIBCPP_ASSERT(__width != 0,
+                   "A zero value isn't allowed and should be impossible, "
+                   "due to validations in this function");
+    return __r.__ptr;
+  }
+
+  void _LIBCPP_HIDE_FROM_ABI constexpr __substitute_width_arg_id(auto __arg) {
+    _LIBCPP_ASSERT(__width_as_arg == 1,
+                   "Substitute width called when no substitution is required");
+
+    // The clearing of the flag isn't required but looks better when debugging
+    // the code.
+    __width_as_arg = 0;
+    __width = __substitute_arg_id(__arg);
+    if (__width == 0)
+      __throw_format_error(
+          "A format-spec width field replacement should have a positive value");
+  }
+};
+
+class _LIBCPP_TYPE_VIS __parser_precision {
+public:
+  /** Contains a precision or an arg-id. */
+  uint32_t __precision : 31 {__format::__number_max};
+  /**
+   * Determines whether the value stored is a precision or an arg-id.
+   *
+   * @note Since @ref __precision == @ref __format::__number_max is a valid
+   * value, the default value contains an arg-id of INT32_MAX. (This number of
+   * arguments isn't supported by compilers.)  This is used to detect whether
+   * the std-format-spec contains a precision field.
+   */
+  uint32_t __precision_as_arg : 1 {1};
+
+protected:
+  /**
+   * Does the supplied std-format-spec contain a precision field?
+   *
+   * When the field isn't present there's no truncating required. This can be
+   * used to optimize the formatting.
+   */
+  constexpr bool __has_precision_field() const noexcept {
+
+    return __precision_as_arg == 0 ||             // Contains a value?
+           __precision != __format::__number_max; // The arg-id is valid?
+  }
+
+  /**
+   * Does the supplied precision field contain an arg-id?
+   *
+   * If @c true the formatter needs to call @ref __substitute_precision_arg_id.
+   */
+  constexpr bool __precision_needs_substitution() const noexcept {
+    return __precision_as_arg && __precision != __format::__number_max;
+  }
+
+  template <class _CharT>
+  _LIBCPP_HIDE_FROM_ABI constexpr const _CharT*
+  __parse(const _CharT* __begin, const _CharT* __end, auto& __parse_ctx) {
+    if (*__begin != _CharT('.'))
+      return __begin;
+
+    ++__begin;
+    if (__begin == __end)
+      __throw_format_error("End of input while parsing format-spec precision");
+
+    if (*__begin == _CharT('0')) {
+      ++__begin;
+      if (__begin != __end && *__begin >= '0' && *__begin <= '9')
+        __throw_format_error(
+            "A format-spec precision field shouldn't have a leading zero");
+
+      __precision = 0;
+      __precision_as_arg = 0;
+      return __begin;
+    }
+
+    if (*__begin == _CharT('{')) {
+      __format::__parse_number_result __arg_id =
+          __parse_arg_id(++__begin, __end, __parse_ctx);
+      _LIBCPP_ASSERT(__arg_id.__value != __format::__number_max,
+                     "Unsupported number of arguments, since this number of "
+                     "arguments is used a special value");
+      __precision = __arg_id.__value;
+      return __arg_id.__ptr;
+    }
+
+    if (*__begin < _CharT('0') || *__begin > _CharT('9'))
+      __throw_format_error(
+          "The format-spec precision field doesn't contain a value or arg-id");
+
+    __format::__parse_number_result __r =
+        __format::__parse_number(__begin, __end);
+    __precision = __r.__value;
+    __precision_as_arg = 0;
+    return __r.__ptr;
+  }
+
+  void _LIBCPP_HIDE_FROM_ABI constexpr __substitute_precision_arg_id(
+      auto __arg) {
+    _LIBCPP_ASSERT(
+        __precision_as_arg == 1 && __precision != __format::__number_max,
+        "Substitute precision called when no substitution is required");
+
+    // The clearing of the flag isn't required but looks better when debugging
+    // the code.
+    __precision_as_arg = 0;
+    __precision = __substitute_arg_id(__arg);
+  }
+};
+
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr const _CharT*
+__parse_locale_specific_form(const _CharT* __begin, _Flags& __flags) noexcept {
+  if (*__begin == _CharT('L')) {
+    __flags.__locale_specific_form = true;
+    ++__begin;
+  }
+
+  return __begin;
+}
+
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr const _CharT*
+__parse_type(const _CharT* __begin, _Flags& __flags) {
+
+  // Determines the type. It does not validate whether the selected type is
+  // valid. Most formatters have optional fields that are only allowed for
+  // certain types. These parsers need to do validation after the type has
+  // been parsed. So its easier to implement the validation for all types in
+  // the specific parse function.
+  switch (*__begin) {
+  case 'A':
+    __flags.__type = _Flags::_Type::__float_hexadecimal_upper_case;
+    break;
+  case 'B':
+    __flags.__type = _Flags::_Type::__binary_upper_case;
+    break;
+  case 'E':
+    __flags.__type = _Flags::_Type::__scientific_upper_case;
+    break;
+  case 'F':
+    __flags.__type = _Flags::_Type::__fixed_upper_case;
+    break;
+  case 'G':
+    __flags.__type = _Flags::_Type::__general_upper_case;
+    break;
+  case 'X':
+    __flags.__type = _Flags::_Type::__hexadecimal_upper_case;
+    break;
+  case 'a':
+    __flags.__type = _Flags::_Type::__float_hexadecimal_lower_case;
+    break;
+  case 'b':
+    __flags.__type = _Flags::_Type::__binary_lower_case;
+    break;
+  case 'c':
+    __flags.__type = _Flags::_Type::__char;
+    break;
+  case 'd':
+    __flags.__type = _Flags::_Type::__decimal;
+    break;
+  case 'e':
+    __flags.__type = _Flags::_Type::__scientific_lower_case;
+    break;
+  case 'f':
+    __flags.__type = _Flags::_Type::__fixed_lower_case;
+    break;
+  case 'g':
+    __flags.__type = _Flags::_Type::__general_lower_case;
+    break;
+  case 'o':
+    __flags.__type = _Flags::_Type::__octal;
+    break;
+  case 'p':
+    __flags.__type = _Flags::_Type::__pointer;
+    break;
+  case 's':
+    __flags.__type = _Flags::_Type::__string;
+    break;
+  case 'x':
+    __flags.__type = _Flags::_Type::__hexadecimal_lower_case;
+    break;
+  default:
+    return __begin;
+  }
+  return ++__begin;
+}
+
+/**
+ * The parser for the std-format-spec.
+ *
+ * [format.string.std]/1 specifies the std-format-spec:
+ *   fill-and-align sign # 0 width precision L type
+ *
+ * All these fields are optional. Whether these fields can be used depend on:
+ * - The type supplied to the format string.
+ *   E.g. A string never uses the sign field so the field may not be set.
+ *   This constrain is validated by the parsers in this file.
+ * - The supplied value for the optional type field.
+ *   E.g. A int formatted as decimal uses the sign field.
+ *   When formatted as a char the sign field may no longer be set.
+ *   This constrain isn't validated by the parsers in this file.
+ *
+ * The base classes are ordered to minimize the amount of padding.
+ *
+ * This implements the parser for the string types.
+ */
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS __parser_string
+    : public __parser_width,              // provides __width(|as_arg)
+      public __parser_precision,          // provides __precision(|as_arg)
+      public __parser_fill_align<_CharT>, // provides __fill and uses __flags
+      public _Flags                       // provides __flags
+{
+public:
+  using char_type = _CharT;
+
+  _LIBCPP_HIDE_FROM_ABI constexpr __parser_string() {
+    this->__alignment = _Flags::_Alignment::__left;
+  }
+
+  /**
+   * The low-level std-format-spec parse function.
+   *
+   * @pre __begin points at the beginning of the std-format-spec. This means
+   * directly after the ':'.
+   * @pre The std-format-spec parses the entire input, or the first unmatched
+   * character is a '}'.
+   *
+   * @returns The iterator pointing at the last parsed character.
+   */
+  _LIBCPP_HIDE_FROM_ABI constexpr auto parse(auto& __parse_ctx)
+      -> decltype(__parse_ctx.begin()) {
+    auto __it = __parse(__parse_ctx);
+    __process_display_type();
+    return __it;
+  }
+
+private:
+  /**
+   * Parses the std-format-spec.
+   *
+   * @throws __throw_format_error When @a __parse_ctx contains an ill-formed
+   *                               std-format-spec.
+   *
+   * @returns An iterator to the end of input or point at the closing '}'.
+   */
+  _LIBCPP_HIDE_FROM_ABI constexpr auto __parse(auto& __parse_ctx)
+      -> decltype(__parse_ctx.begin()) {
+
+    auto __begin = __parse_ctx.begin();
+    auto __end = __parse_ctx.end();
+    if (__begin == __end)
+      return __begin;
+
+    __begin = __parser_fill_align<_CharT>::__parse(__begin, __end,
+                                                   static_cast<_Flags&>(*this));
+    if (__begin == __end)
+      return __begin;
+
+    __begin = __parser_width::__parse(__begin, __end, __parse_ctx);
+    if (__begin == __end)
+      return __begin;
+
+    __begin = __parser_precision::__parse(__begin, __end, __parse_ctx);
+    if (__begin == __end)
+      return __begin;
+
+    __begin = __parse_type(__begin, static_cast<_Flags&>(*this));
+
+    if (__begin != __end && *__begin != _CharT('}'))
+      __throw_format_error(
+          "The format-spec should consume the input or end with a '}'");
+
+    return __begin;
+  }
+
+  /** Processes the parsed std-format-spec based on the parsed display type. */
+  void _LIBCPP_HIDE_FROM_ABI constexpr __process_display_type() {
+    switch (this->__type) {
+    case _Flags::_Type::__default:
+    case _Flags::_Type::__string:
+      break;
+
+    default:
+      __throw_format_error("The format-spec type has a type not supported for "
+                           "a string argument");
+    }
+  }
+};
+
+/**
+ * The parser for the std-format-spec.
+ *
+ * This implements the parser for the integral types. This includes the
+ * character type and boolean type.
+ *
+ * See @ref __parser_string.
+ */
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS __parser_integral
+    : public __parser_width,              // provides __width(|as_arg)
+      public __parser_fill_align<_CharT>, // provides __fill and uses __flags
+      public _Flags                       // provides __flags
+{
+public:
+  using char_type = _CharT;
+
+protected:
+  /**
+   * The low-level std-format-spec parse function.
+   *
+   * @pre __begin points at the beginning of the std-format-spec. This means
+   * directly after the ':'.
+   * @pre The std-format-spec parses the entire input, or the first unmatched
+   * character is a '}'.
+   *
+   * @returns The iterator pointing at the last parsed character.
+   */
+  _LIBCPP_HIDE_FROM_ABI constexpr auto __parse(auto& __parse_ctx)
+      -> decltype(__parse_ctx.begin()) {
+    auto __begin = __parse_ctx.begin();
+    auto __end = __parse_ctx.end();
+    if (__begin == __end)
+      return __begin;
+
+    __begin = __parser_fill_align<_CharT>::__parse(__begin, __end,
+                                                   static_cast<_Flags&>(*this));
+    if (__begin == __end)
+      return __begin;
+
+    __begin = __parse_sign(__begin, static_cast<_Flags&>(*this));
+    if (__begin == __end)
+      return __begin;
+
+    __begin = __parse_alternate_form(__begin, static_cast<_Flags&>(*this));
+    if (__begin == __end)
+      return __begin;
+
+    __begin = __parse_zero_padding(__begin, static_cast<_Flags&>(*this));
+    if (__begin == __end)
+      return __begin;
+
+    __begin = __parser_width::__parse(__begin, __end, __parse_ctx);
+    if (__begin == __end)
+      return __begin;
+
+    __begin =
+        __parse_locale_specific_form(__begin, static_cast<_Flags&>(*this));
+    if (__begin == __end)
+      return __begin;
+
+    __begin = __parse_type(__begin, static_cast<_Flags&>(*this));
+
+    if (__begin != __end && *__begin != _CharT('}'))
+      __throw_format_error(
+          "The format-spec should consume the input or end with a '}'");
+
+    return __begin;
+  }
+
+  /**
+   * Handles the post-parsing updates for the integer types.
+   *
+   * Updates the zero-padding and alignment for integer types.
+   *
+   * [format.string.std]/13
+   *   If the 0 character and an align option both appear, the 0 character is
+   *   ignored.
+   *
+   * For the formatter a @ref __default alignment means zero-padding. Update
+   * the alignment based on parsed format string.
+   */
+  _LIBCPP_HIDE_FROM_ABI constexpr void __handle_integer() noexcept {
+    this->__zero_padding &= this->__alignment == _Flags::_Alignment::__default;
+    if (!this->__zero_padding &&
+        this->__alignment == _Flags::_Alignment::__default)
+      this->__alignment = _Flags::_Alignment::__right;
+  }
+
+  /**
+   * Handles the post-parsing updates for the character types.
+   *
+   * Sets the alignment and validates the format flags set for a character type.
+   *
+   * At the moment the validation for a character and a Boolean behave the
+   * same, but this may change in the future.
+   * Specifically at the moment the locale-specific form is allowed for the
+   * char output type, but it has no effect on the output.
+   */
+  _LIBCPP_HIDE_FROM_ABI constexpr void __handle_char() { __handle_bool(); }
+
+  /**
+   * Handles the post-parsing updates for the Boolean types.
+   *
+   * Sets the alignment and validates the format flags set for a Boolean type.
+   */
+  _LIBCPP_HIDE_FROM_ABI constexpr void __handle_bool() {
+    if (this->__sign != _Flags::_Sign::__default)
+      __throw_format_error("A sign field isn't allowed in this format-spec");
+
+    if (this->__alternate_form)
+      __throw_format_error(
+          "An alternate form field isn't allowed in this format-spec");
+
+    if (this->__zero_padding)
+      __throw_format_error(
+          "A zero-padding field isn't allowed in this format-spec");
+
+    if (this->__alignment == _Flags::_Alignment::__default)
+      this->__alignment = _Flags::_Alignment::__left;
+  }
+};
+
+// TODO FMT Add a parser for floating-point values.
+// TODO FMT Add a parser for pointer values.
+
+/** Helper struct returned from @ref __get_string_alignment. */
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS __string_alignment {
+  /** Points beyond the last character to write to the output. */
+  const _CharT* __last;
+  /**
+   * The estimated number of columns in the output or 0.
+   *
+   * Only when the output needs to be aligned it's required to know the exact
+   * number of columns in the output. So if the formatted output has only a
+   * minimum width the exact size isn't important. It's only important to know
+   * the minimum has been reached. The minimum width is the width specified in
+   * the format-spec.
+   *
+   * For example in this code @code std::format("{:10}", MyString); @endcode
+   * the width estimation can stop once the algorithm has determined the output
+   * width is 10 columns.
+   *
+   * So if:
+   * * @ref __align == @c true the @ref __size is the estimated number of
+   *   columns required.
+   * * @ref __align == @c false the @ref __size is the estimated number of
+   *   columns required or 0 when the estimation algorithm stopped prematurely.
+   */
+  ptrdiff_t __size;
+  /**
+   * Does the output need to be aligned.
+   *
+   * When alignment is needed the output algorithm needs to add the proper
+   * padding. Else the output algorithm just needs to copy the input up to
+   * @ref __last.
+   */
+  bool __align;
+};
+
+#ifndef _LIBCPP_HAS_NO_UNICODE
+namespace __detail {
+
+/**
+ * Unicode column width estimates.
+ *
+ * Unicode can be stored in several formats: UTF-8, UTF-16, and UTF-32.
+ * Depending on format the relation between the number of code units stored and
+ * the number of output columns differs. The first relation is the number of
+ * code units forming a code point. (The text assumes the code units are
+ * unsigned.)
+ * - UTF-8 The number of code units is between one and four. The first 127
+ *   Unicode code points match the ASCII character set. When the highest bit is
+ *   set it means the code point has more than one code unit.
+ * - UTF-16: The number of code units is between 1 and 2. When the first
+ *   code unit is in the range [0xd800,0xdfff) it means the code point uses two
+ *   code units.
+ * - UTF-32: The number of code units is always one.
+ *
+ * The code point to the number of columns isn't well defined. The code uses the
+ * estimations defined in [format.string.std]/11. This list might change in the
+ * future.
+ *
+ * The algorithm of @ref __get_string_alignment uses two different scanners:
+ * - The simple scanner @ref __estimate_column_width_fast. This scanner assumes
+ *   1 code unit is 1 column. This scanner stops when it can't be sure the
+ *   assumption is valid:
+ *   - UTF-8 when the code point is encoded in more than 1 code unit.
+ *   - UTF-16 and UTF-32 when the first multi-column code point is encountered.
+ *     (The code unit's value is lower than 0xd800 so the 2 code unit encoding
+ *     is irrelevant for this scanner.)
+ *   Due to these assumptions the scanner is faster than the full scanner. It
+ *   can process all text only containing ASCII. For UTF-16/32 it can process
+ *   most (all?) European languages. (Note the set it can process might be
+ *   reduced in the future, due to updates in the scanning rules.)
+ * - The full scanner @ref __estimate_column_width. This scanner, if needed,
+ *   converts multiple code units into one code point then converts the code
+ *   point to a column width.
+ *
+ * See also:
+ * - [format.string.general]/11
+ * - https://en.wikipedia.org/wiki/UTF-8#Encoding
+ * - https://en.wikipedia.org/wiki/UTF-16#U+D800_to_U+DFFF
+ */
+
+/**
+ * The first 2 column code point.
+ *
+ * This is the point where the fast UTF-16/32 scanner needs to stop processing.
+ */
+inline constexpr uint32_t __two_column_code_point = 0x1100;
+
+/** Helper concept for an UTF-8 character type. */
+template <class _CharT>
+concept __utf8_character = same_as<_CharT, char> || same_as<_CharT, char8_t>;
+
+/** Helper concept for an UTF-16 character type. */
+template <class _CharT>
+concept __utf16_character = (same_as<_CharT, wchar_t> && sizeof(wchar_t) == 2) || same_as<_CharT, char16_t>;
+
+/** Helper concept for an UTF-32 character type. */
+template <class _CharT>
+concept __utf32_character = (same_as<_CharT, wchar_t> && sizeof(wchar_t) == 4) || same_as<_CharT, char32_t>;
+
+/** Helper concept for an UTF-16 or UTF-32 character type. */
+template <class _CharT>
+concept __utf16_or_32_character = __utf16_character<_CharT> || __utf32_character<_CharT>;
+
+/**
+ * Converts a code point to the column width.
+ *
+ * The estimations are conforming to [format.string.general]/11
+ *
+ * This version expects a value less than 0x1'0000, which is a 3-byte UTF-8
+ * character.
+ */
+_LIBCPP_HIDE_FROM_ABI inline constexpr int __column_width_3(uint32_t __c) noexcept {
+  _LIBCPP_ASSERT(__c < 0x1'0000,
+                 "Use __column_width_4 or __column_width for larger values");
+
+  // clang-format off
+  return 1 + (__c >= 0x1100 && (__c <= 0x115f ||
+             (__c >= 0x2329 && (__c <= 0x232a ||
+             (__c >= 0x2e80 && (__c <= 0x303e ||
+             (__c >= 0x3040 && (__c <= 0xa4cf ||
+             (__c >= 0xac00 && (__c <= 0xd7a3 ||
+             (__c >= 0xf900 && (__c <= 0xfaff ||
+             (__c >= 0xfe10 && (__c <= 0xfe19 ||
+             (__c >= 0xfe30 && (__c <= 0xfe6f ||
+             (__c >= 0xff00 && (__c <= 0xff60 ||
+             (__c >= 0xffe0 && (__c <= 0xffe6
+             ))))))))))))))))))));
+  // clang-format on
+}
+
+/**
+ * @overload
+ *
+ * This version expects a value greater than or equal to 0x1'0000, which is a
+ * 4-byte UTF-8 character.
+ */
+_LIBCPP_HIDE_FROM_ABI inline constexpr int __column_width_4(uint32_t __c) noexcept {
+  _LIBCPP_ASSERT(__c >= 0x1'0000,
+                 "Use __column_width_3 or __column_width for smaller values");
+
+  // clang-format off
+  return 1 + (__c >= 0x1'f300 && (__c <= 0x1'f64f ||
+             (__c >= 0x1'f900 && (__c <= 0x1'f9ff ||
+             (__c >= 0x2'0000 && (__c <= 0x2'fffd ||
+             (__c >= 0x3'0000 && (__c <= 0x3'fffd
+             ))))))));
+  // clang-format on
+}
+
+/**
+ * @overload
+ *
+ * The general case, accepting all values.
+ */
+_LIBCPP_HIDE_FROM_ABI inline constexpr int __column_width(uint32_t __c) noexcept {
+  if (__c < 0x1'0000)
+    return __column_width_3(__c);
+
+  return __column_width_4(__c);
+}
+
+/**
+ * Estimate the column width for the UTF-8 sequence using the fast algorithm.
+ */
+template <__utf8_character _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr const _CharT*
+__estimate_column_width_fast(const _CharT* __first,
+                             const _CharT* __last) noexcept {
+  return _VSTD::find_if(__first, __last,
+                        [](unsigned char __c) { return __c & 0x80; });
+}
+
+/**
+ * @overload
+ *
+ * The implementation for UTF-16/32.
+ */
+template <__utf16_or_32_character _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr const _CharT*
+__estimate_column_width_fast(const _CharT* __first,
+                             const _CharT* __last) noexcept {
+  return _VSTD::find_if(__first, __last,
+                        [](uint32_t __c) { return __c >= 0x1100; });
+}
+
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS __column_width_result {
+  /** The number of output columns. */
+  size_t __width;
+  /**
+   * The last parsed element.
+   *
+   * This limits the original output to fit in the wanted number of columns.
+   */
+  const _CharT* __ptr;
+};
+
+/**
+ * Small helper to determine the width of malformed Unicode.
+ *
+ * @note This function's only needed for UTF-8. During scanning UTF-8 there
+ * are multiple place where it can be detected that the Unicode is malformed.
+ * UTF-16 only requires 1 test and UTF-32 requires no testing.
+ */
+template <__utf8_character _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr __column_width_result<_CharT>
+__estimate_column_width_malformed(const _CharT* __first, const _CharT* __last,
+                                  size_t __maximum, size_t __result) noexcept {
+  size_t __size = __last - __first;
+  size_t __n = _VSTD::min(__size, __maximum);
+  return {__result + __n, __first + __n};
+}
+
+/**
+ * Determines the number of output columns needed to render the input.
+ *
+ * @note When the scanner encounters malformed Unicode it acts as-if every code
+ * unit at the end of the input is one output column. It's expected the output
+ * terminal will replace these malformed code units with a one column
+ * replacement characters.
+ *
+ * @param __first   Points to the first element of the input range.
+ * @param __last    Points beyond the last element of the input range.
+ * @param __maximum The maximum number of output columns. The returned number
+ *                  of estimated output columns will not exceed this value.
+ */
+template <__utf8_character _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr __column_width_result<_CharT>
+__estimate_column_width(const _CharT* __first, const _CharT* __last,
+                        size_t __maximum) noexcept {
+  size_t __result = 0;
+
+  while (__first != __last) {
+    // Based on the number of leading 1 bits the number of code units in the
+    // code point can be determined. See
+    // https://en.wikipedia.org/wiki/UTF-8#Encoding
+    switch (_VSTD::countl_one(static_cast<unsigned char>(*__first))) {
+    case 0: // 1-code unit encoding: all 1 column
+      ++__result;
+      ++__first;
+      break;
+
+    case 2: // 2-code unit encoding: all 1 column
+      // Malformed Unicode.
+      if (__last - __first < 2) [[unlikely]]
+        return __estimate_column_width_malformed(__first, __last, __maximum,
+                                                 __result);
+      __first += 2;
+      ++__result;
+      break;
+
+    case 3: // 3-code unit encoding: either 1 or 2 columns
+      // Malformed Unicode.
+      if (__last - __first < 3) [[unlikely]]
+        return __estimate_column_width_malformed(__first, __last, __maximum,
+                                                 __result);
+      {
+        uint32_t __c = static_cast<unsigned char>(*__first++) & 0x0f;
+        __c <<= 6;
+        __c |= static_cast<unsigned char>(*__first++) & 0x3f;
+        __c <<= 6;
+        __c |= static_cast<unsigned char>(*__first++) & 0x3f;
+        __result += __column_width_3(__c);
+        if (__result > __maximum)
+          return {__result - 2, __first - 3};
+      }
+      break;
+    case 4: // 4-code unit encoding: either 1 or 2 columns
+      // Malformed Unicode.
+      if (__last - __first < 4) [[unlikely]]
+        return __estimate_column_width_malformed(__first, __last, __maximum,
+                                                 __result);
+      {
+        uint32_t __c = static_cast<unsigned char>(*__first++) & 0x07;
+        __c <<= 6;
+        __c |= static_cast<unsigned char>(*__first++) & 0x3f;
+        __c <<= 6;
+        __c |= static_cast<unsigned char>(*__first++) & 0x3f;
+        __c <<= 6;
+        __c |= static_cast<unsigned char>(*__first++) & 0x3f;
+        __result += __column_width_4(__c);
+        if (__result > __maximum)
+          return {__result - 2, __first - 4};
+      }
+      break;
+    default:
+      // Malformed Unicode.
+      return __estimate_column_width_malformed(__first, __last, __maximum,
+                                               __result);
+    }
+
+    if (__result >= __maximum)
+      return {__result, __first};
+  }
+  return {__result, __first};
+}
+
+template <__utf16_character _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr __column_width_result<_CharT>
+__estimate_column_width(const _CharT* __first, const _CharT* __last,
+                        size_t __maximum) noexcept {
+  size_t __result = 0;
+
+  while (__first != __last) {
+    uint32_t __c = *__first;
+    // Is the code unit part of a surrogate pair? See
+    // https://en.wikipedia.org/wiki/UTF-16#U+D800_to_U+DFFF
+    if (__c >= 0xd800 && __c <= 0xDfff) {
+      // Malformed Unicode.
+      if (__last - __first < 2) [[unlikely]]
+        return {__result + 1, __first + 1};
+
+      __c -= 0xd800;
+      __c <<= 10;
+      __c += (*(__first + 1) - 0xdc00);
+      __c += 0x10'000;
+
+      __result += __column_width_4(__c);
+      if (__result > __maximum)
+        return {__result - 2, __first};
+      __first += 2;
+    } else {
+      __result += __column_width_3(__c);
+      if (__result > __maximum)
+        return {__result - 2, __first};
+      ++__first;
+    }
+
+    if (__result >= __maximum)
+      return {__result, __first};
+  }
+
+  return {__result, __first};
+}
+
+template <__utf32_character _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr __column_width_result<_CharT>
+__estimate_column_width(const _CharT* __first, const _CharT* __last,
+                        size_t __maximum) noexcept {
+  size_t __result = 0;
+
+  while (__first != __last) {
+    wchar_t __c = *__first;
+    __result += __column_width(__c);
+
+    if (__result > __maximum)
+      return {__result - 2, __first};
+
+    ++__first;
+    if (__result >= __maximum)
+      return {__result, __first};
+  }
+
+  return {__result, __first};
+}
+
+} // namespace __detail
+
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr __string_alignment<_CharT>
+__get_string_alignment(const _CharT* __first, const _CharT* __last,
+                       ptrdiff_t __width, ptrdiff_t __precision) noexcept {
+  _LIBCPP_ASSERT(__width != 0 || __precision != -1,
+                 "The function has no effect and shouldn't be used");
+
+  // TODO FMT There might be more optimizations possible:
+  // If __precision == __format::__number_max and the encoding is:
+  // * UTF-8  : 4 * (__last - __first) >= __width
+  // * UTF-16 : 2 * (__last - __first) >= __width
+  // * UTF-32 : (__last - __first) >= __width
+  // In these cases it's certain the output is at least the requested width.
+  // It's unknown how often this happens in practice. For now the improvement
+  // isn't implemented.
+
+  /*
+   * First assume there are no special Unicode code units in the input.
+   * - Apply the precision (this may reduce the size of the input). When
+   *   __precison == -1 this step is omitted.
+   * - Scan for special code units in the input.
+   * If our assumption was correct the __pos will be at the end of the input.
+   */
+  const ptrdiff_t __length = __last - __first;
+  const _CharT* __limit =
+      __first +
+      (__precision == -1 ? __length : _VSTD::min(__length, __precision));
+  ptrdiff_t __size = __limit - __first;
+  const _CharT* __pos =
+      __detail::__estimate_column_width_fast(__first, __limit);
+
+  if (__pos == __limit)
+    return {__limit, __size, __size < __width};
+
+  /*
+   * Our assumption was wrong, there are special Unicode code units.
+   * The range [__first, __pos) contains a set of code units with the
+   * following property:
+   *      Every _CharT in the range will be rendered in 1 column.
+   *
+   * If there's no maximum width and the parsed size already exceeds the
+   *   minimum required width. The real size isn't important. So bail out.
+   */
+  if (__precision == -1 && (__pos - __first) >= __width)
+    return {__last, 0, false};
+
+  /* If there's a __precision, truncate the output to that width. */
+  ptrdiff_t __prefix = __pos - __first;
+  if (__precision != -1) {
+    _LIBCPP_ASSERT(__precision > __prefix, "Logic error.");
+    auto __lengh_info = __detail::__estimate_column_width(
+        __pos, __last, __precision - __prefix);
+    __size = __lengh_info.__width + __prefix;
+    return {__lengh_info.__ptr, __size, __size < __width};
+  }
+
+  /* Else use __width to determine the number of required padding characters. */
+  _LIBCPP_ASSERT(__width > __prefix, "Logic error.");
+  /*
+   * The column width is always one or two columns. For the precision the wanted
+   * column width is the maximum, for the width it's the minimum. Using the
+   * width estimation with its truncating behavior will result in the wrong
+   * result in the following case:
+   * - The last code unit processed requires two columns and exceeds the
+   *   maximum column width.
+   * By increasing the __maximum by one avoids this issue. (It means it may
+   * pass one code point more than required to determine the proper result;
+   * that however isn't a problem for the algorithm.)
+   */
+  size_t __maximum = 1 + __width - __prefix;
+  auto __lengh_info =
+      __detail::__estimate_column_width(__pos, __last, __maximum);
+  if (__lengh_info.__ptr != __last) {
+    // Consumed the width number of code units. The exact size of the string
+    // is unknown. We only know we don't need to align the output.
+    _LIBCPP_ASSERT(static_cast<ptrdiff_t>(__lengh_info.__width + __prefix) >=
+                       __width,
+                   "Logic error");
+    return {__last, 0, false};
+  }
+
+  __size = __lengh_info.__width + __prefix;
+  return {__last, __size, __size < __width};
+}
+#else  // _LIBCPP_HAS_NO_UNICODE
+template <class _CharT>
+_LIBCPP_HIDE_FROM_ABI constexpr __string_alignment<_CharT>
+__get_string_alignment(const _CharT* __first, const _CharT* __last,
+                       ptrdiff_t __width, ptrdiff_t __precision) noexcept {
+  const ptrdiff_t __length = __last - __first;
+  const _CharT* __limit =
+      __first +
+      (__precision == -1 ? __length : _VSTD::min(__length, __precision));
+  ptrdiff_t __size = __limit - __first;
+  return {__limit, __size, __size < __width};
+}
+#endif // _LIBCPP_HAS_NO_UNICODE
+
+} // namespace __format_spec
+
+# endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___FORMAT_PARSER_STD_FORMAT_SPEC_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__function_like.h b/contrib/libs/cxxsupp/libcxx/include/__function_like.h
new file mode 100644
index 00000000000..4075355174d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__function_like.h
@@ -0,0 +1,51 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_FUNCTION_LIKE_H
+#define _LIBCPP___ITERATOR_FUNCTION_LIKE_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+// Per [range.iter.ops.general] and [algorithms.requirements], functions in namespace std::ranges
+// can't be found by ADL and inhibit ADL when found by unqualified lookup. The easiest way to
+// facilitate this is to use function objects.
+//
+// Since these are still standard library functions, we use `__function_like` to eliminate most of
+// the properties that function objects get by default (e.g. semiregularity, addressability), to
+// limit the surface area of the unintended public interface, so as to curb the effect of Hyrum's
+// law.
+struct __function_like {
+  __function_like() = delete;
+  __function_like(__function_like const&) = delete;
+  __function_like& operator=(__function_like const&) = delete;
+
+  void operator&() const = delete;
+
+  struct __tag { };
+
+protected:
+  constexpr explicit __function_like(__tag) noexcept {}
+  ~__function_like() = default;
+};
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_FUNCTION_LIKE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/binary_function.h b/contrib/libs/cxxsupp/libcxx/include/__functional/binary_function.h
new file mode 100644
index 00000000000..8ca7b06662a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/binary_function.h
@@ -0,0 +1,31 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_BINARY_FUNCTION_H
+#define _LIBCPP___FUNCTIONAL_BINARY_FUNCTION_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Arg1, class _Arg2, class _Result>
+struct _LIBCPP_TEMPLATE_VIS binary_function
+{
+    typedef _Arg1   first_argument_type;
+    typedef _Arg2   second_argument_type;
+    typedef _Result result_type;
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_BINARY_FUNCTION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/binary_negate.h b/contrib/libs/cxxsupp/libcxx/include/__functional/binary_negate.h
new file mode 100644
index 00000000000..4fc3f1ba287
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/binary_negate.h
@@ -0,0 +1,50 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_BINARY_NEGATE_H
+#define _LIBCPP___FUNCTIONAL_BINARY_NEGATE_H
+
+#include <__config>
+#include <__functional/binary_function.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_NEGATORS)
+
+template <class _Predicate>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 binary_negate
+    : public binary_function<typename _Predicate::first_argument_type,
+                             typename _Predicate::second_argument_type,
+                             bool>
+{
+    _Predicate __pred_;
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit _LIBCPP_CONSTEXPR_AFTER_CXX11
+    binary_negate(const _Predicate& __pred) : __pred_(__pred) {}
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const typename _Predicate::first_argument_type& __x,
+                    const typename _Predicate::second_argument_type& __y) const
+        {return !__pred_(__x, __y);}
+};
+
+template <class _Predicate>
+_LIBCPP_DEPRECATED_IN_CXX17 inline _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+binary_negate<_Predicate>
+not2(const _Predicate& __pred) {return binary_negate<_Predicate>(__pred);}
+
+#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_NEGATORS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_BINARY_NEGATE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/bind.h b/contrib/libs/cxxsupp/libcxx/include/__functional/bind.h
new file mode 100644
index 00000000000..80dbd6ca895
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/bind.h
@@ -0,0 +1,412 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_BIND_H
+#define _LIBCPP___FUNCTIONAL_BIND_H
+
+#include <__config>
+#include <__functional/weak_result_type.h>
+#include <__functional/invoke.h>
+#include <cstddef>
+#include <tuple>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _Tp> struct __is_bind_expression : public false_type {};
+template<class _Tp> struct _LIBCPP_TEMPLATE_VIS is_bind_expression
+    : public __is_bind_expression<typename remove_cv<_Tp>::type> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr size_t is_bind_expression_v = is_bind_expression<_Tp>::value;
+#endif
+
+template<class _Tp> struct __is_placeholder : public integral_constant<int, 0> {};
+template<class _Tp> struct _LIBCPP_TEMPLATE_VIS is_placeholder
+    : public __is_placeholder<typename remove_cv<_Tp>::type> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr size_t is_placeholder_v = is_placeholder<_Tp>::value;
+#endif
+
+namespace placeholders
+{
+
+template <int _Np> struct __ph {};
+
+#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
+_LIBCPP_FUNC_VIS extern const __ph<1>   _1;
+_LIBCPP_FUNC_VIS extern const __ph<2>   _2;
+_LIBCPP_FUNC_VIS extern const __ph<3>   _3;
+_LIBCPP_FUNC_VIS extern const __ph<4>   _4;
+_LIBCPP_FUNC_VIS extern const __ph<5>   _5;
+_LIBCPP_FUNC_VIS extern const __ph<6>   _6;
+_LIBCPP_FUNC_VIS extern const __ph<7>   _7;
+_LIBCPP_FUNC_VIS extern const __ph<8>   _8;
+_LIBCPP_FUNC_VIS extern const __ph<9>   _9;
+_LIBCPP_FUNC_VIS extern const __ph<10> _10;
+#else
+/* inline */ constexpr __ph<1>   _1{};
+/* inline */ constexpr __ph<2>   _2{};
+/* inline */ constexpr __ph<3>   _3{};
+/* inline */ constexpr __ph<4>   _4{};
+/* inline */ constexpr __ph<5>   _5{};
+/* inline */ constexpr __ph<6>   _6{};
+/* inline */ constexpr __ph<7>   _7{};
+/* inline */ constexpr __ph<8>   _8{};
+/* inline */ constexpr __ph<9>   _9{};
+/* inline */ constexpr __ph<10> _10{};
+#endif // defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
+
+}  // placeholders
+
+template<int _Np>
+struct __is_placeholder<placeholders::__ph<_Np> >
+    : public integral_constant<int, _Np> {};
+
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Uj>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp&
+__mu(reference_wrapper<_Tp> __t, _Uj&)
+{
+    return __t.get();
+}
+
+template <class _Ti, class ..._Uj, size_t ..._Indx>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __invoke_of<_Ti&, _Uj...>::type
+__mu_expand(_Ti& __ti, tuple<_Uj...>& __uj, __tuple_indices<_Indx...>)
+{
+    return __ti(_VSTD::forward<_Uj>(_VSTD::get<_Indx>(__uj))...);
+}
+
+template <class _Ti, class ..._Uj>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __enable_if_t
+<
+    is_bind_expression<_Ti>::value,
+    __invoke_of<_Ti&, _Uj...>
+>::type
+__mu(_Ti& __ti, tuple<_Uj...>& __uj)
+{
+    typedef typename __make_tuple_indices<sizeof...(_Uj)>::type __indices;
+    return _VSTD::__mu_expand(__ti, __uj, __indices());
+}
+
+template <bool IsPh, class _Ti, class _Uj>
+struct __mu_return2 {};
+
+template <class _Ti, class _Uj>
+struct __mu_return2<true, _Ti, _Uj>
+{
+    typedef typename tuple_element<is_placeholder<_Ti>::value - 1, _Uj>::type type;
+};
+
+template <class _Ti, class _Uj>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    0 < is_placeholder<_Ti>::value,
+    typename __mu_return2<0 < is_placeholder<_Ti>::value, _Ti, _Uj>::type
+>::type
+__mu(_Ti&, _Uj& __uj)
+{
+    const size_t _Indx = is_placeholder<_Ti>::value - 1;
+    return _VSTD::forward<typename tuple_element<_Indx, _Uj>::type>(_VSTD::get<_Indx>(__uj));
+}
+
+template <class _Ti, class _Uj>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    !is_bind_expression<_Ti>::value &&
+    is_placeholder<_Ti>::value == 0 &&
+    !__is_reference_wrapper<_Ti>::value,
+    _Ti&
+>::type
+__mu(_Ti& __ti, _Uj&)
+{
+    return __ti;
+}
+
+template <class _Ti, bool IsReferenceWrapper, bool IsBindEx, bool IsPh,
+          class _TupleUj>
+struct __mu_return_impl;
+
+template <bool _Invokable, class _Ti, class ..._Uj>
+struct __mu_return_invokable  // false
+{
+    typedef __nat type;
+};
+
+template <class _Ti, class ..._Uj>
+struct __mu_return_invokable<true, _Ti, _Uj...>
+{
+    typedef typename __invoke_of<_Ti&, _Uj...>::type type;
+};
+
+template <class _Ti, class ..._Uj>
+struct __mu_return_impl<_Ti, false, true, false, tuple<_Uj...> >
+    : public __mu_return_invokable<__invokable<_Ti&, _Uj...>::value, _Ti, _Uj...>
+{
+};
+
+template <class _Ti, class _TupleUj>
+struct __mu_return_impl<_Ti, false, false, true, _TupleUj>
+{
+    typedef typename tuple_element<is_placeholder<_Ti>::value - 1,
+                                   _TupleUj>::type&& type;
+};
+
+template <class _Ti, class _TupleUj>
+struct __mu_return_impl<_Ti, true, false, false, _TupleUj>
+{
+    typedef typename _Ti::type& type;
+};
+
+template <class _Ti, class _TupleUj>
+struct __mu_return_impl<_Ti, false, false, false, _TupleUj>
+{
+    typedef _Ti& type;
+};
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4296 )
+#endif
+
+template <class _Ti, class _TupleUj>
+struct __mu_return
+    : public __mu_return_impl<_Ti,
+                              __is_reference_wrapper<_Ti>::value,
+                              is_bind_expression<_Ti>::value,
+                              0 < is_placeholder<_Ti>::value &&
+                              is_placeholder<_Ti>::value <= tuple_size<_TupleUj>::value,
+                              _TupleUj>
+{
+};
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+template <class _Fp, class _BoundArgs, class _TupleUj>
+struct __is_valid_bind_return
+{
+    static const bool value = false;
+};
+
+template <class _Fp, class ..._BoundArgs, class _TupleUj>
+struct __is_valid_bind_return<_Fp, tuple<_BoundArgs...>, _TupleUj>
+{
+    static const bool value = __invokable<_Fp,
+                    typename __mu_return<_BoundArgs, _TupleUj>::type...>::value;
+};
+
+template <class _Fp, class ..._BoundArgs, class _TupleUj>
+struct __is_valid_bind_return<_Fp, const tuple<_BoundArgs...>, _TupleUj>
+{
+    static const bool value = __invokable<_Fp,
+                    typename __mu_return<const _BoundArgs, _TupleUj>::type...>::value;
+};
+
+template <class _Fp, class _BoundArgs, class _TupleUj,
+          bool = __is_valid_bind_return<_Fp, _BoundArgs, _TupleUj>::value>
+struct __bind_return;
+
+template <class _Fp, class ..._BoundArgs, class _TupleUj>
+struct __bind_return<_Fp, tuple<_BoundArgs...>, _TupleUj, true>
+{
+    typedef typename __invoke_of
+    <
+        _Fp&,
+        typename __mu_return
+        <
+            _BoundArgs,
+            _TupleUj
+        >::type...
+    >::type type;
+};
+
+template <class _Fp, class ..._BoundArgs, class _TupleUj>
+struct __bind_return<_Fp, const tuple<_BoundArgs...>, _TupleUj, true>
+{
+    typedef typename __invoke_of
+    <
+        _Fp&,
+        typename __mu_return
+        <
+            const _BoundArgs,
+            _TupleUj
+        >::type...
+    >::type type;
+};
+
+template <class _Fp, class _BoundArgs, size_t ..._Indx, class _Args>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __bind_return<_Fp, _BoundArgs, _Args>::type
+__apply_functor(_Fp& __f, _BoundArgs& __bound_args, __tuple_indices<_Indx...>,
+                _Args&& __args)
+{
+    return _VSTD::__invoke(__f, _VSTD::__mu(_VSTD::get<_Indx>(__bound_args), __args)...);
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4296 )
+#endif
+
+template<class _Fp, class ..._BoundArgs>
+class __bind
+#if _LIBCPP_STD_VER <= 17 || !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public __weak_result_type<typename decay<_Fp>::type>
+#endif
+{
+protected:
+    typedef typename decay<_Fp>::type _Fd;
+    typedef tuple<typename decay<_BoundArgs>::type...> _Td;
+private:
+    _Fd __f_;
+    _Td __bound_args_;
+
+    typedef typename __make_tuple_indices<sizeof...(_BoundArgs)>::type __indices;
+public:
+    template <class _Gp, class ..._BA,
+              class = typename enable_if
+                               <
+                                  is_constructible<_Fd, _Gp>::value &&
+                                  !is_same<typename remove_reference<_Gp>::type,
+                                           __bind>::value
+                               >::type>
+      _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+      explicit __bind(_Gp&& __f, _BA&& ...__bound_args)
+        : __f_(_VSTD::forward<_Gp>(__f)),
+          __bound_args_(_VSTD::forward<_BA>(__bound_args)...) {}
+
+    template <class ..._Args>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+        typename __bind_return<_Fd, _Td, tuple<_Args&&...> >::type
+        operator()(_Args&& ...__args)
+        {
+            return _VSTD::__apply_functor(__f_, __bound_args_, __indices(),
+                                  tuple<_Args&&...>(_VSTD::forward<_Args>(__args)...));
+        }
+
+    template <class ..._Args>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+        typename __bind_return<const _Fd, const _Td, tuple<_Args&&...> >::type
+        operator()(_Args&& ...__args) const
+        {
+            return _VSTD::__apply_functor(__f_, __bound_args_, __indices(),
+                                   tuple<_Args&&...>(_VSTD::forward<_Args>(__args)...));
+        }
+};
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+#if defined(__CUDACC__) && defined(_MSC_VER)
+#   define Y_CUDAFE_MSVC_BUG
+#endif
+
+template<class _Fp, class ..._BoundArgs>
+struct __is_bind_expression<__bind<_Fp, _BoundArgs...> > : public true_type {};
+
+template<class _Rp, class _Fp, class ..._BoundArgs>
+class __bind_r
+    : public __bind<_Fp, _BoundArgs...>
+{
+    typedef __bind<_Fp, _BoundArgs...> base;
+    typedef typename base::_Fd _Fd;
+#if !defined(Y_CUDAFE_MSVC_BUG)
+    typedef typename base::_Td _Td;
+#else
+    typedef typename tuple<typename decay<_BoundArgs>::type...> _Td;
+#endif
+public:
+    typedef _Rp result_type;
+
+
+    template <class _Gp, class ..._BA,
+              class = typename enable_if
+                               <
+                                  is_constructible<_Fd, _Gp>::value &&
+                                  !is_same<typename remove_reference<_Gp>::type,
+                                           __bind_r>::value
+                               >::type>
+      _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+      explicit __bind_r(_Gp&& __f, _BA&& ...__bound_args)
+        : base(_VSTD::forward<_Gp>(__f),
+               _VSTD::forward<_BA>(__bound_args)...) {}
+
+    template <class ..._Args>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+        typename enable_if
+        <
+            is_convertible<typename __bind_return<_Fd, _Td, tuple<_Args&&...> >::type,
+                           result_type>::value || is_void<_Rp>::value,
+            result_type
+        >::type
+        operator()(_Args&& ...__args)
+        {
+            typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+            return _Invoker::__call(static_cast<base&>(*this), _VSTD::forward<_Args>(__args)...);
+        }
+
+    template <class ..._Args>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+        typename enable_if
+        <
+            is_convertible<typename __bind_return<const _Fd, const _Td, tuple<_Args&&...> >::type,
+                           result_type>::value || is_void<_Rp>::value,
+            result_type
+        >::type
+        operator()(_Args&& ...__args) const
+        {
+            typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+            return _Invoker::__call(static_cast<base const&>(*this), _VSTD::forward<_Args>(__args)...);
+        }
+};
+
+template<class _Rp, class _Fp, class ..._BoundArgs>
+struct __is_bind_expression<__bind_r<_Rp, _Fp, _BoundArgs...> > : public true_type {};
+
+template<class _Fp, class ..._BoundArgs>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+__bind<_Fp, _BoundArgs...>
+bind(_Fp&& __f, _BoundArgs&&... __bound_args)
+{
+    typedef __bind<_Fp, _BoundArgs...> type;
+    return type(_VSTD::forward<_Fp>(__f), _VSTD::forward<_BoundArgs>(__bound_args)...);
+}
+
+template<class _Rp, class _Fp, class ..._BoundArgs>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+__bind_r<_Rp, _Fp, _BoundArgs...>
+bind(_Fp&& __f, _BoundArgs&&... __bound_args)
+{
+    typedef __bind_r<_Rp, _Fp, _BoundArgs...> type;
+    return type(_VSTD::forward<_Fp>(__f), _VSTD::forward<_BoundArgs>(__bound_args)...);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_BIND_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/bind_back.h b/contrib/libs/cxxsupp/libcxx/include/__functional/bind_back.h
new file mode 100644
index 00000000000..a0089e1fb09
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/bind_back.h
@@ -0,0 +1,65 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_BIND_BACK_H
+#define _LIBCPP___FUNCTIONAL_BIND_BACK_H
+
+#include <__config>
+#include <__functional/invoke.h>
+#include <__functional/perfect_forward.h>
+#include <__utility/forward.h>
+#include <__utility/integer_sequence.h>
+#include <tuple>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+template <size_t _NBound, class = make_index_sequence<_NBound>>
+struct __bind_back_op;
+
+template <size_t _NBound, size_t ..._Ip>
+struct __bind_back_op<_NBound, index_sequence<_Ip...>> {
+    template <class _Fn, class _Bound, class ..._Args>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Fn&& __f, _Bound&& __bound, _Args&& ...__args) const
+        noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)..., _VSTD::get<_Ip>(_VSTD::forward<_Bound>(__bound))...)))
+        -> decltype(      _VSTD::invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)..., _VSTD::get<_Ip>(_VSTD::forward<_Bound>(__bound))...))
+        { return          _VSTD::invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)..., _VSTD::get<_Ip>(_VSTD::forward<_Bound>(__bound))...); }
+};
+
+template <class _Fn, class _BoundArgs>
+struct __bind_back_t : __perfect_forward<__bind_back_op<tuple_size_v<_BoundArgs>>, _Fn, _BoundArgs> {
+    using __perfect_forward<__bind_back_op<tuple_size_v<_BoundArgs>>, _Fn, _BoundArgs>::__perfect_forward;
+};
+
+template <class _Fn, class ..._Args, class = enable_if_t<
+    _And<
+        is_constructible<decay_t<_Fn>, _Fn>,
+        is_move_constructible<decay_t<_Fn>>,
+        is_constructible<decay_t<_Args>, _Args>...,
+        is_move_constructible<decay_t<_Args>>...
+    >::value
+>>
+_LIBCPP_HIDE_FROM_ABI
+constexpr auto __bind_back(_Fn&& __f, _Args&&... __args)
+    noexcept(noexcept(__bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>(_VSTD::forward<_Fn>(__f), _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...))))
+    -> decltype(      __bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>(_VSTD::forward<_Fn>(__f), _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...)))
+    { return          __bind_back_t<decay_t<_Fn>, tuple<decay_t<_Args>...>>(_VSTD::forward<_Fn>(__f), _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...)); }
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_BIND_BACK_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/bind_front.h b/contrib/libs/cxxsupp/libcxx/include/__functional/bind_front.h
new file mode 100644
index 00000000000..86d4594b657
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/bind_front.h
@@ -0,0 +1,58 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_BIND_FRONT_H
+#define _LIBCPP___FUNCTIONAL_BIND_FRONT_H
+
+#include <__config>
+#include <__functional/perfect_forward.h>
+#include <__functional/invoke.h>
+#include <type_traits>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+struct __bind_front_op {
+    template <class ..._Args>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Args&& ...__args) const
+        noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Args>(__args)...)))
+        -> decltype(      _VSTD::invoke(_VSTD::forward<_Args>(__args)...))
+        { return          _VSTD::invoke(_VSTD::forward<_Args>(__args)...); }
+};
+
+template <class _Fn, class ..._BoundArgs>
+struct __bind_front_t : __perfect_forward<__bind_front_op, _Fn, _BoundArgs...> {
+    using __perfect_forward<__bind_front_op, _Fn, _BoundArgs...>::__perfect_forward;
+};
+
+template <class _Fn, class... _Args, class = enable_if_t<
+    _And<
+        is_constructible<decay_t<_Fn>, _Fn>,
+        is_move_constructible<decay_t<_Fn>>,
+        is_constructible<decay_t<_Args>, _Args>...,
+        is_move_constructible<decay_t<_Args>>...
+    >::value
+>>
+_LIBCPP_HIDE_FROM_ABI
+constexpr auto bind_front(_Fn&& __f, _Args&&... __args) {
+    return __bind_front_t<decay_t<_Fn>, decay_t<_Args>...>(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...);
+}
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_BIND_FRONT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/binder1st.h b/contrib/libs/cxxsupp/libcxx/include/__functional/binder1st.h
new file mode 100644
index 00000000000..5dd8f5cf015
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/binder1st.h
@@ -0,0 +1,54 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_BINDER1ST_H
+#define _LIBCPP___FUNCTIONAL_BINDER1ST_H
+
+#include <__config>
+#include <__functional/unary_function.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_BINDERS)
+
+template <class __Operation>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 binder1st
+    : public unary_function<typename __Operation::second_argument_type,
+                            typename __Operation::result_type>
+{
+protected:
+    __Operation                               op;
+    typename __Operation::first_argument_type value;
+public:
+    _LIBCPP_INLINE_VISIBILITY binder1st(const __Operation& __x,
+                               const typename __Operation::first_argument_type __y)
+        : op(__x), value(__y) {}
+    _LIBCPP_INLINE_VISIBILITY typename __Operation::result_type operator()
+        (typename __Operation::second_argument_type& __x) const
+            {return op(value, __x);}
+    _LIBCPP_INLINE_VISIBILITY typename __Operation::result_type operator()
+        (const typename __Operation::second_argument_type& __x) const
+            {return op(value, __x);}
+};
+
+template <class __Operation, class _Tp>
+_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
+binder1st<__Operation>
+bind1st(const __Operation& __op, const _Tp& __x)
+    {return binder1st<__Operation>(__op, __x);}
+
+#endif // _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_BINDERS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_BINDER1ST_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/binder2nd.h b/contrib/libs/cxxsupp/libcxx/include/__functional/binder2nd.h
new file mode 100644
index 00000000000..3ed5f5bf454
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/binder2nd.h
@@ -0,0 +1,54 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_BINDER2ND_H
+#define _LIBCPP___FUNCTIONAL_BINDER2ND_H
+
+#include <__config>
+#include <__functional/unary_function.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_BINDERS)
+
+template <class __Operation>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 binder2nd
+    : public unary_function<typename __Operation::first_argument_type,
+                            typename __Operation::result_type>
+{
+protected:
+    __Operation                                op;
+    typename __Operation::second_argument_type value;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    binder2nd(const __Operation& __x, const typename __Operation::second_argument_type __y)
+        : op(__x), value(__y) {}
+    _LIBCPP_INLINE_VISIBILITY typename __Operation::result_type operator()
+        (      typename __Operation::first_argument_type& __x) const
+            {return op(__x, value);}
+    _LIBCPP_INLINE_VISIBILITY typename __Operation::result_type operator()
+        (const typename __Operation::first_argument_type& __x) const
+            {return op(__x, value);}
+};
+
+template <class __Operation, class _Tp>
+_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
+binder2nd<__Operation>
+bind2nd(const __Operation& __op, const _Tp& __x)
+    {return binder2nd<__Operation>(__op, __x);}
+
+#endif // _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_BINDERS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_BINDER2ND_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/compose.h b/contrib/libs/cxxsupp/libcxx/include/__functional/compose.h
new file mode 100644
index 00000000000..d9d75875c2a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/compose.h
@@ -0,0 +1,52 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_COMPOSE_H
+#define _LIBCPP___FUNCTIONAL_COMPOSE_H
+
+#include <__config>
+#include <__functional/invoke.h>
+#include <__functional/perfect_forward.h>
+#include <__utility/forward.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+struct __compose_op {
+    template<class _Fn1, class _Fn2, class ..._Args>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Fn1&& __f1, _Fn2&& __f2, _Args&&... __args) const
+        noexcept(noexcept(_VSTD::invoke(_VSTD::forward<_Fn1>(__f1), _VSTD::invoke(_VSTD::forward<_Fn2>(__f2), _VSTD::forward<_Args>(__args)...))))
+        -> decltype(      _VSTD::invoke(_VSTD::forward<_Fn1>(__f1), _VSTD::invoke(_VSTD::forward<_Fn2>(__f2), _VSTD::forward<_Args>(__args)...)))
+        { return          _VSTD::invoke(_VSTD::forward<_Fn1>(__f1), _VSTD::invoke(_VSTD::forward<_Fn2>(__f2), _VSTD::forward<_Args>(__args)...)); }
+};
+
+template <class _Fn1, class _Fn2>
+struct __compose_t : __perfect_forward<__compose_op, _Fn1, _Fn2> {
+    using __perfect_forward<__compose_op, _Fn1, _Fn2>::__perfect_forward;
+};
+
+template <class _Fn1, class _Fn2>
+_LIBCPP_HIDE_FROM_ABI
+constexpr auto __compose(_Fn1&& __f1, _Fn2&& __f2)
+    noexcept(noexcept(__compose_t<decay_t<_Fn1>, decay_t<_Fn2>>(_VSTD::forward<_Fn1>(__f1), _VSTD::forward<_Fn2>(__f2))))
+    -> decltype(      __compose_t<decay_t<_Fn1>, decay_t<_Fn2>>(_VSTD::forward<_Fn1>(__f1), _VSTD::forward<_Fn2>(__f2)))
+    { return          __compose_t<decay_t<_Fn1>, decay_t<_Fn2>>(_VSTD::forward<_Fn1>(__f1), _VSTD::forward<_Fn2>(__f2)); }
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_COMPOSE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/default_searcher.h b/contrib/libs/cxxsupp/libcxx/include/__functional/default_searcher.h
new file mode 100644
index 00000000000..1acbc1883af
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/default_searcher.h
@@ -0,0 +1,56 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_DEFAULT_SEARCHER_H
+#define _LIBCPP___FUNCTIONAL_DEFAULT_SEARCHER_H
+
+#include <__algorithm/search.h>
+#include <__config>
+#include <__functional/operations.h>
+#include <__iterator/iterator_traits.h>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+// default searcher
+template<class _ForwardIterator, class _BinaryPredicate = equal_to<>>
+class _LIBCPP_TEMPLATE_VIS default_searcher {
+public:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    default_searcher(_ForwardIterator __f, _ForwardIterator __l,
+                       _BinaryPredicate __p = _BinaryPredicate())
+        : __first_(__f), __last_(__l), __pred_(__p) {}
+
+    template <typename _ForwardIterator2>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    pair<_ForwardIterator2, _ForwardIterator2>
+    operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const
+    {
+        return _VSTD::__search(__f, __l, __first_, __last_, __pred_,
+            typename iterator_traits<_ForwardIterator>::iterator_category(),
+            typename iterator_traits<_ForwardIterator2>::iterator_category());
+    }
+
+private:
+    _ForwardIterator __first_;
+    _ForwardIterator __last_;
+    _BinaryPredicate __pred_;
+    };
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_DEFAULT_SEARCHER_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/function.h b/contrib/libs/cxxsupp/libcxx/include/__functional/function.h
new file mode 100644
index 00000000000..1fa4f79975b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/function.h
@@ -0,0 +1,2817 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_FUNCTION_H
+#define _LIBCPP___FUNCTIONAL_FUNCTION_H
+
+#include <__config>
+#include <__debug>
+#include <__functional/binary_function.h>
+#include <__functional/invoke.h>
+#include <__functional/unary_function.h>
+#include <__iterator/iterator_traits.h>
+#include <__memory/allocator_traits.h>
+#include <__memory/compressed_pair.h>
+#include <__memory/shared_ptr.h>
+#include <exception>
+#include <memory> // TODO: replace with <__memory/__builtin_new_allocator.h>
+#include <type_traits>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// bad_function_call
+
+class _LIBCPP_EXCEPTION_ABI bad_function_call
+    : public exception
+{
+#ifdef _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
+public:
+    virtual ~bad_function_call() _NOEXCEPT;
+
+    virtual const char* what() const _NOEXCEPT;
+#endif
+};
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+void __throw_bad_function_call()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw bad_function_call();
+#else
+    _VSTD::abort();
+#endif
+}
+
+#if defined(_LIBCPP_CXX03_LANG) && !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS) && __has_attribute(deprecated)
+#   define _LIBCPP_DEPRECATED_CXX03_FUNCTION \
+        __attribute__((deprecated("Using std::function in C++03 is not supported anymore. Please upgrade to C++11 or later, or use a different type")))
+#else
+#   define _LIBCPP_DEPRECATED_CXX03_FUNCTION /* nothing */
+#endif
+
+template<class _Fp> class _LIBCPP_DEPRECATED_CXX03_FUNCTION _LIBCPP_TEMPLATE_VIS function; // undefined
+
+namespace __function
+{
+
+template<class _Rp>
+struct __maybe_derive_from_unary_function
+{
+};
+
+template<class _Rp, class _A1>
+struct __maybe_derive_from_unary_function<_Rp(_A1)>
+    : public unary_function<_A1, _Rp>
+{
+};
+
+template<class _Rp>
+struct __maybe_derive_from_binary_function
+{
+};
+
+template<class _Rp, class _A1, class _A2>
+struct __maybe_derive_from_binary_function<_Rp(_A1, _A2)>
+    : public binary_function<_A1, _A2, _Rp>
+{
+};
+
+template <class _Fp>
+_LIBCPP_INLINE_VISIBILITY
+bool __not_null(_Fp const&) { return true; }
+
+template <class _Fp>
+_LIBCPP_INLINE_VISIBILITY
+bool __not_null(_Fp* __ptr) { return __ptr; }
+
+template <class _Ret, class _Class>
+_LIBCPP_INLINE_VISIBILITY
+bool __not_null(_Ret _Class::*__ptr) { return __ptr; }
+
+template <class _Fp>
+_LIBCPP_INLINE_VISIBILITY
+bool __not_null(function<_Fp> const& __f) { return !!__f; }
+
+#ifdef _LIBCPP_HAS_EXTENSION_BLOCKS
+template <class _Rp, class ..._Args>
+_LIBCPP_INLINE_VISIBILITY
+bool __not_null(_Rp (^__p)(_Args...)) { return __p; }
+#endif
+
+} // namespace __function
+
+#ifndef _LIBCPP_CXX03_LANG
+
+namespace __function {
+
+// __alloc_func holds a functor and an allocator.
+
+template <class _Fp, class _Ap, class _FB> class __alloc_func;
+template <class _Fp, class _FB>
+class __default_alloc_func;
+
+template <class _Fp, class _Ap, class _Rp, class... _ArgTypes>
+class __alloc_func<_Fp, _Ap, _Rp(_ArgTypes...)>
+{
+    __compressed_pair<_Fp, _Ap> __f_;
+
+  public:
+    typedef _LIBCPP_NODEBUG _Fp _Target;
+    typedef _LIBCPP_NODEBUG _Ap _Alloc;
+
+    _LIBCPP_INLINE_VISIBILITY
+    const _Target& __target() const { return __f_.first(); }
+
+    // WIN32 APIs may define __allocator, so use __get_allocator instead.
+    _LIBCPP_INLINE_VISIBILITY
+    const _Alloc& __get_allocator() const { return __f_.second(); }
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __alloc_func(_Target&& __f)
+        : __f_(piecewise_construct, _VSTD::forward_as_tuple(_VSTD::move(__f)),
+               _VSTD::forward_as_tuple())
+    {
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __alloc_func(const _Target& __f, const _Alloc& __a)
+        : __f_(piecewise_construct, _VSTD::forward_as_tuple(__f),
+               _VSTD::forward_as_tuple(__a))
+    {
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __alloc_func(const _Target& __f, _Alloc&& __a)
+        : __f_(piecewise_construct, _VSTD::forward_as_tuple(__f),
+               _VSTD::forward_as_tuple(_VSTD::move(__a)))
+    {
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __alloc_func(_Target&& __f, _Alloc&& __a)
+        : __f_(piecewise_construct, _VSTD::forward_as_tuple(_VSTD::move(__f)),
+               _VSTD::forward_as_tuple(_VSTD::move(__a)))
+    {
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Rp operator()(_ArgTypes&&... __arg)
+    {
+        typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+        return _Invoker::__call(__f_.first(),
+                                _VSTD::forward<_ArgTypes>(__arg)...);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __alloc_func* __clone() const
+    {
+        typedef allocator_traits<_Alloc> __alloc_traits;
+        typedef
+            typename __rebind_alloc_helper<__alloc_traits, __alloc_func>::type
+                _AA;
+        _AA __a(__f_.second());
+        typedef __allocator_destructor<_AA> _Dp;
+        unique_ptr<__alloc_func, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+        ::new ((void*)__hold.get()) __alloc_func(__f_.first(), _Alloc(__a));
+        return __hold.release();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void destroy() _NOEXCEPT { __f_.~__compressed_pair<_Target, _Alloc>(); }
+
+    static void __destroy_and_delete(__alloc_func* __f) {
+      typedef allocator_traits<_Alloc> __alloc_traits;
+      typedef typename __rebind_alloc_helper<__alloc_traits, __alloc_func>::type
+          _FunAlloc;
+      _FunAlloc __a(__f->__get_allocator());
+      __f->destroy();
+      __a.deallocate(__f, 1);
+    }
+};
+
+template <class _Fp, class _Rp, class... _ArgTypes>
+class __default_alloc_func<_Fp, _Rp(_ArgTypes...)> {
+  _Fp __f_;
+
+public:
+  typedef _LIBCPP_NODEBUG _Fp _Target;
+
+  _LIBCPP_INLINE_VISIBILITY
+  const _Target& __target() const { return __f_; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  explicit __default_alloc_func(_Target&& __f) : __f_(_VSTD::move(__f)) {}
+
+  _LIBCPP_INLINE_VISIBILITY
+  explicit __default_alloc_func(const _Target& __f) : __f_(__f) {}
+
+  _LIBCPP_INLINE_VISIBILITY
+  _Rp operator()(_ArgTypes&&... __arg) {
+    typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+    return _Invoker::__call(__f_, _VSTD::forward<_ArgTypes>(__arg)...);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  __default_alloc_func* __clone() const {
+      __builtin_new_allocator::__holder_t __hold =
+        __builtin_new_allocator::__allocate_type<__default_alloc_func>(1);
+    __default_alloc_func* __res =
+        ::new ((void*)__hold.get()) __default_alloc_func(__f_);
+    (void)__hold.release();
+    return __res;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void destroy() _NOEXCEPT { __f_.~_Target(); }
+
+  static void __destroy_and_delete(__default_alloc_func* __f) {
+    __f->destroy();
+      __builtin_new_allocator::__deallocate_type<__default_alloc_func>(__f, 1);
+  }
+};
+
+// __base provides an abstract interface for copyable functors.
+
+template<class _Fp> class _LIBCPP_TEMPLATE_VIS __base;
+
+template<class _Rp, class ..._ArgTypes>
+class __base<_Rp(_ArgTypes...)>
+{
+    __base(const __base&);
+    __base& operator=(const __base&);
+public:
+    _LIBCPP_INLINE_VISIBILITY __base() {}
+    _LIBCPP_INLINE_VISIBILITY virtual ~__base() {}
+    virtual __base* __clone() const = 0;
+    virtual void __clone(__base*) const = 0;
+    virtual void destroy() _NOEXCEPT = 0;
+    virtual void destroy_deallocate() _NOEXCEPT = 0;
+    virtual _Rp operator()(_ArgTypes&& ...) = 0;
+#ifndef _LIBCPP_NO_RTTI
+    virtual const void* target(const type_info&) const _NOEXCEPT = 0;
+    virtual const std::type_info& target_type() const _NOEXCEPT = 0;
+#endif // _LIBCPP_NO_RTTI
+};
+
+// __func implements __base for a given functor type.
+
+template<class _FD, class _Alloc, class _FB> class __func;
+
+template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
+class __func<_Fp, _Alloc, _Rp(_ArgTypes...)>
+    : public  __base<_Rp(_ArgTypes...)>
+{
+    __alloc_func<_Fp, _Alloc, _Rp(_ArgTypes...)> __f_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __func(_Fp&& __f)
+        : __f_(_VSTD::move(__f)) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __func(const _Fp& __f, const _Alloc& __a)
+        : __f_(__f, __a) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __func(const _Fp& __f, _Alloc&& __a)
+        : __f_(__f, _VSTD::move(__a)) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __func(_Fp&& __f, _Alloc&& __a)
+        : __f_(_VSTD::move(__f), _VSTD::move(__a)) {}
+
+    virtual __base<_Rp(_ArgTypes...)>* __clone() const;
+    virtual void __clone(__base<_Rp(_ArgTypes...)>*) const;
+    virtual void destroy() _NOEXCEPT;
+    virtual void destroy_deallocate() _NOEXCEPT;
+    virtual _Rp operator()(_ArgTypes&&... __arg);
+#ifndef _LIBCPP_NO_RTTI
+    virtual const void* target(const type_info&) const _NOEXCEPT;
+    virtual const std::type_info& target_type() const _NOEXCEPT;
+#endif // _LIBCPP_NO_RTTI
+};
+
+template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
+__base<_Rp(_ArgTypes...)>*
+__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::__clone() const
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    typedef typename __rebind_alloc_helper<__alloc_traits, __func>::type _Ap;
+    _Ap __a(__f_.__get_allocator());
+    typedef __allocator_destructor<_Ap> _Dp;
+    unique_ptr<__func, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+    ::new ((void*)__hold.get()) __func(__f_.__target(), _Alloc(__a));
+    return __hold.release();
+}
+
+template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
+void
+__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::__clone(__base<_Rp(_ArgTypes...)>* __p) const
+{
+    ::new ((void*)__p) __func(__f_.__target(), __f_.__get_allocator());
+}
+
+template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
+void
+__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::destroy() _NOEXCEPT
+{
+    __f_.destroy();
+}
+
+template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
+void
+__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::destroy_deallocate() _NOEXCEPT
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    typedef typename __rebind_alloc_helper<__alloc_traits, __func>::type _Ap;
+    _Ap __a(__f_.__get_allocator());
+    __f_.destroy();
+    __a.deallocate(this, 1);
+}
+
+template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
+_Rp
+__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::operator()(_ArgTypes&& ... __arg)
+{
+    return __f_(_VSTD::forward<_ArgTypes>(__arg)...);
+}
+
+#ifndef _LIBCPP_NO_RTTI
+
+template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
+const void*
+__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::target(const type_info& __ti) const _NOEXCEPT
+{
+    if (__ti == typeid(_Fp))
+        return &__f_.__target();
+    return nullptr;
+}
+
+template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
+const std::type_info&
+__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::target_type() const _NOEXCEPT
+{
+    return typeid(_Fp);
+}
+
+#endif // _LIBCPP_NO_RTTI
+
+// __value_func creates a value-type from a __func.
+
+template <class _Fp> class __value_func;
+
+template <class _Rp, class... _ArgTypes> class __value_func<_Rp(_ArgTypes...)>
+{
+    typename aligned_storage<3 * sizeof(void*)>::type __buf_;
+
+    typedef __base<_Rp(_ArgTypes...)> __func;
+    __func* __f_;
+
+    _LIBCPP_NO_CFI static __func* __as_base(void* p)
+    {
+        return reinterpret_cast<__func*>(p);
+    }
+
+  public:
+    _LIBCPP_INLINE_VISIBILITY
+    __value_func() _NOEXCEPT : __f_(nullptr) {}
+
+    template <class _Fp, class _Alloc>
+    _LIBCPP_INLINE_VISIBILITY __value_func(_Fp&& __f, const _Alloc& __a)
+        : __f_(nullptr)
+    {
+        typedef allocator_traits<_Alloc> __alloc_traits;
+        typedef __function::__func<_Fp, _Alloc, _Rp(_ArgTypes...)> _Fun;
+        typedef typename __rebind_alloc_helper<__alloc_traits, _Fun>::type
+            _FunAlloc;
+
+        if (__function::__not_null(__f))
+        {
+            _FunAlloc __af(__a);
+            if (sizeof(_Fun) <= sizeof(__buf_) &&
+                is_nothrow_copy_constructible<_Fp>::value &&
+                is_nothrow_copy_constructible<_FunAlloc>::value)
+            {
+                __f_ =
+                    ::new ((void*)&__buf_) _Fun(_VSTD::move(__f), _Alloc(__af));
+            }
+            else
+            {
+                typedef __allocator_destructor<_FunAlloc> _Dp;
+                unique_ptr<__func, _Dp> __hold(__af.allocate(1), _Dp(__af, 1));
+                ::new ((void*)__hold.get()) _Fun(_VSTD::move(__f), _Alloc(__a));
+                __f_ = __hold.release();
+            }
+        }
+    }
+
+    template <class _Fp,
+        class = typename enable_if<!is_same<typename decay<_Fp>::type, __value_func>::value>::type>
+    _LIBCPP_INLINE_VISIBILITY explicit __value_func(_Fp&& __f)
+        : __value_func(_VSTD::forward<_Fp>(__f), allocator<_Fp>()) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __value_func(const __value_func& __f)
+    {
+        if (__f.__f_ == nullptr)
+            __f_ = nullptr;
+        else if ((void*)__f.__f_ == &__f.__buf_)
+        {
+            __f_ = __as_base(&__buf_);
+            __f.__f_->__clone(__f_);
+        }
+        else
+            __f_ = __f.__f_->__clone();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __value_func(__value_func&& __f) _NOEXCEPT
+    {
+        if (__f.__f_ == nullptr)
+            __f_ = nullptr;
+        else if ((void*)__f.__f_ == &__f.__buf_)
+        {
+            __f_ = __as_base(&__buf_);
+            __f.__f_->__clone(__f_);
+        }
+        else
+        {
+            __f_ = __f.__f_;
+            __f.__f_ = nullptr;
+        }
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~__value_func()
+    {
+        if ((void*)__f_ == &__buf_)
+            __f_->destroy();
+        else if (__f_)
+            __f_->destroy_deallocate();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __value_func& operator=(__value_func&& __f)
+    {
+        *this = nullptr;
+        if (__f.__f_ == nullptr)
+            __f_ = nullptr;
+        else if ((void*)__f.__f_ == &__f.__buf_)
+        {
+            __f_ = __as_base(&__buf_);
+            __f.__f_->__clone(__f_);
+        }
+        else
+        {
+            __f_ = __f.__f_;
+            __f.__f_ = nullptr;
+        }
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __value_func& operator=(nullptr_t)
+    {
+        __func* __f = __f_;
+        __f_ = nullptr;
+        if ((void*)__f == &__buf_)
+            __f->destroy();
+        else if (__f)
+            __f->destroy_deallocate();
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Rp operator()(_ArgTypes&&... __args) const
+    {
+        if (__f_ == nullptr)
+            __throw_bad_function_call();
+        return (*__f_)(_VSTD::forward<_ArgTypes>(__args)...);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(__value_func& __f) _NOEXCEPT
+    {
+        if (&__f == this)
+            return;
+        if ((void*)__f_ == &__buf_ && (void*)__f.__f_ == &__f.__buf_)
+        {
+            typename aligned_storage<sizeof(__buf_)>::type __tempbuf;
+            __func* __t = __as_base(&__tempbuf);
+            __f_->__clone(__t);
+            __f_->destroy();
+            __f_ = nullptr;
+            __f.__f_->__clone(__as_base(&__buf_));
+            __f.__f_->destroy();
+            __f.__f_ = nullptr;
+            __f_ = __as_base(&__buf_);
+            __t->__clone(__as_base(&__f.__buf_));
+            __t->destroy();
+            __f.__f_ = __as_base(&__f.__buf_);
+        }
+        else if ((void*)__f_ == &__buf_)
+        {
+            __f_->__clone(__as_base(&__f.__buf_));
+            __f_->destroy();
+            __f_ = __f.__f_;
+            __f.__f_ = __as_base(&__f.__buf_);
+        }
+        else if ((void*)__f.__f_ == &__f.__buf_)
+        {
+            __f.__f_->__clone(__as_base(&__buf_));
+            __f.__f_->destroy();
+            __f.__f_ = __f_;
+            __f_ = __as_base(&__buf_);
+        }
+        else
+            _VSTD::swap(__f_, __f.__f_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit operator bool() const _NOEXCEPT { return __f_ != nullptr; }
+
+#ifndef _LIBCPP_NO_RTTI
+    _LIBCPP_INLINE_VISIBILITY
+    const std::type_info& target_type() const _NOEXCEPT
+    {
+        if (__f_ == nullptr)
+            return typeid(void);
+        return __f_->target_type();
+    }
+
+    template <typename _Tp>
+    _LIBCPP_INLINE_VISIBILITY const _Tp* target() const _NOEXCEPT
+    {
+        if (__f_ == nullptr)
+            return nullptr;
+        return (const _Tp*)__f_->target(typeid(_Tp));
+    }
+#endif // _LIBCPP_NO_RTTI
+};
+
+// Storage for a functor object, to be used with __policy to manage copy and
+// destruction.
+union __policy_storage
+{
+    mutable char __small[sizeof(void*) * 2];
+    void* __large;
+};
+
+// True if _Fun can safely be held in __policy_storage.__small.
+template <typename _Fun>
+struct __use_small_storage
+    : public integral_constant<
+          bool, sizeof(_Fun) <= sizeof(__policy_storage) &&
+                    _LIBCPP_ALIGNOF(_Fun) <= _LIBCPP_ALIGNOF(__policy_storage) &&
+                    is_trivially_copy_constructible<_Fun>::value &&
+                    is_trivially_destructible<_Fun>::value> {};
+
+// Policy contains information about how to copy, destroy, and move the
+// underlying functor. You can think of it as a vtable of sorts.
+struct __policy
+{
+    // Used to copy or destroy __large values. null for trivial objects.
+    void* (*const __clone)(const void*);
+    void (*const __destroy)(void*);
+
+    // True if this is the null policy (no value).
+    const bool __is_null;
+
+    // The target type. May be null if RTTI is disabled.
+    const std::type_info* const __type_info;
+
+    // Returns a pointer to a static policy object suitable for the functor
+    // type.
+    template <typename _Fun>
+    _LIBCPP_INLINE_VISIBILITY static const __policy* __create()
+    {
+        return __choose_policy<_Fun>(__use_small_storage<_Fun>());
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static const __policy* __create_empty()
+    {
+        static const /*_LIBCPP_CONSTEXPR*/ __policy __policy_ = {nullptr, nullptr,
+                                                             true,
+#ifndef _LIBCPP_NO_RTTI
+                                                             &typeid(void)
+#else
+                                                             nullptr
+#endif
+        };
+        return &__policy_;
+    }
+
+  private:
+    template <typename _Fun> static void* __large_clone(const void* __s)
+    {
+        const _Fun* __f = static_cast<const _Fun*>(__s);
+        return __f->__clone();
+    }
+
+    template <typename _Fun>
+    static void __large_destroy(void* __s) {
+      _Fun::__destroy_and_delete(static_cast<_Fun*>(__s));
+    }
+
+    template <typename _Fun>
+    _LIBCPP_INLINE_VISIBILITY static const __policy*
+    __choose_policy(/* is_small = */ false_type) {
+      static const _LIBCPP_CONSTEXPR __policy __policy_ = {
+          &__large_clone<_Fun>, &__large_destroy<_Fun>, false,
+#ifndef _LIBCPP_NO_RTTI
+          &typeid(typename _Fun::_Target)
+#else
+          nullptr
+#endif
+      };
+        return &__policy_;
+    }
+
+    template <typename _Fun>
+    _LIBCPP_INLINE_VISIBILITY static const __policy*
+        __choose_policy(/* is_small = */ true_type)
+    {
+        static const _LIBCPP_CONSTEXPR __policy __policy_ = {
+            nullptr, nullptr, false,
+#ifndef _LIBCPP_NO_RTTI
+            &typeid(typename _Fun::_Target)
+#else
+            nullptr
+#endif
+        };
+        return &__policy_;
+    }
+};
+
+// Used to choose between perfect forwarding or pass-by-value. Pass-by-value is
+// faster for types that can be passed in registers.
+template <typename _Tp>
+using __fast_forward =
+    typename conditional<is_scalar<_Tp>::value, _Tp, _Tp&&>::type;
+
+// __policy_invoker calls an instance of __alloc_func held in __policy_storage.
+
+template <class _Fp> struct __policy_invoker;
+
+template <class _Rp, class... _ArgTypes>
+struct __policy_invoker<_Rp(_ArgTypes...)>
+{
+    typedef _Rp (*__Call)(const __policy_storage*,
+                          __fast_forward<_ArgTypes>...);
+
+    __Call __call_;
+
+    // Creates an invoker that throws bad_function_call.
+    _LIBCPP_INLINE_VISIBILITY
+    __policy_invoker() : __call_(&__call_empty) {}
+
+    // Creates an invoker that calls the given instance of __func.
+    template <typename _Fun>
+    _LIBCPP_INLINE_VISIBILITY static __policy_invoker __create()
+    {
+        return __policy_invoker(&__call_impl<_Fun>);
+    }
+
+  private:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __policy_invoker(__Call __c) : __call_(__c) {}
+
+    static _Rp __call_empty(const __policy_storage*,
+                            __fast_forward<_ArgTypes>...)
+    {
+        __throw_bad_function_call();
+    }
+
+    template <typename _Fun>
+    static _Rp __call_impl(const __policy_storage* __buf,
+                           __fast_forward<_ArgTypes>... __args)
+    {
+        _Fun* __f = reinterpret_cast<_Fun*>(__use_small_storage<_Fun>::value
+                                                ? &__buf->__small
+                                                : __buf->__large);
+        return (*__f)(_VSTD::forward<_ArgTypes>(__args)...);
+    }
+};
+
+// __policy_func uses a __policy and __policy_invoker to create a type-erased,
+// copyable functor.
+
+template <class _Fp> class __policy_func;
+
+template <class _Rp, class... _ArgTypes> class __policy_func<_Rp(_ArgTypes...)>
+{
+    // Inline storage for small objects.
+    __policy_storage __buf_;
+
+    // Calls the value stored in __buf_. This could technically be part of
+    // policy, but storing it here eliminates a level of indirection inside
+    // operator().
+    typedef __function::__policy_invoker<_Rp(_ArgTypes...)> __invoker;
+    __invoker __invoker_;
+
+    // The policy that describes how to move / copy / destroy __buf_. Never
+    // null, even if the function is empty.
+    const __policy* __policy_;
+
+  public:
+    _LIBCPP_INLINE_VISIBILITY
+    __policy_func() : __policy_(__policy::__create_empty()) {}
+
+    template <class _Fp, class _Alloc>
+    _LIBCPP_INLINE_VISIBILITY __policy_func(_Fp&& __f, const _Alloc& __a)
+        : __policy_(__policy::__create_empty())
+    {
+        typedef __alloc_func<_Fp, _Alloc, _Rp(_ArgTypes...)> _Fun;
+        typedef allocator_traits<_Alloc> __alloc_traits;
+        typedef typename __rebind_alloc_helper<__alloc_traits, _Fun>::type
+            _FunAlloc;
+
+        if (__function::__not_null(__f))
+        {
+            __invoker_ = __invoker::template __create<_Fun>();
+            __policy_ = __policy::__create<_Fun>();
+
+            _FunAlloc __af(__a);
+            if (__use_small_storage<_Fun>())
+            {
+                ::new ((void*)&__buf_.__small)
+                    _Fun(_VSTD::move(__f), _Alloc(__af));
+            }
+            else
+            {
+                typedef __allocator_destructor<_FunAlloc> _Dp;
+                unique_ptr<_Fun, _Dp> __hold(__af.allocate(1), _Dp(__af, 1));
+                ::new ((void*)__hold.get())
+                    _Fun(_VSTD::move(__f), _Alloc(__af));
+                __buf_.__large = __hold.release();
+            }
+        }
+    }
+
+    template <class _Fp, class = typename enable_if<!is_same<typename decay<_Fp>::type, __policy_func>::value>::type>
+    _LIBCPP_INLINE_VISIBILITY explicit __policy_func(_Fp&& __f)
+        : __policy_(__policy::__create_empty()) {
+      typedef __default_alloc_func<_Fp, _Rp(_ArgTypes...)> _Fun;
+
+      if (__function::__not_null(__f)) {
+        __invoker_ = __invoker::template __create<_Fun>();
+        __policy_ = __policy::__create<_Fun>();
+        if (__use_small_storage<_Fun>()) {
+          ::new ((void*)&__buf_.__small) _Fun(_VSTD::move(__f));
+        } else {
+          __builtin_new_allocator::__holder_t __hold =
+              __builtin_new_allocator::__allocate_type<_Fun>(1);
+          __buf_.__large = ::new ((void*)__hold.get()) _Fun(_VSTD::move(__f));
+          (void)__hold.release();
+        }
+      }
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __policy_func(const __policy_func& __f)
+        : __buf_(__f.__buf_), __invoker_(__f.__invoker_),
+          __policy_(__f.__policy_)
+    {
+        if (__policy_->__clone)
+            __buf_.__large = __policy_->__clone(__f.__buf_.__large);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __policy_func(__policy_func&& __f)
+        : __buf_(__f.__buf_), __invoker_(__f.__invoker_),
+          __policy_(__f.__policy_)
+    {
+        if (__policy_->__destroy)
+        {
+            __f.__policy_ = __policy::__create_empty();
+            __f.__invoker_ = __invoker();
+        }
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~__policy_func()
+    {
+        if (__policy_->__destroy)
+            __policy_->__destroy(__buf_.__large);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __policy_func& operator=(__policy_func&& __f)
+    {
+        *this = nullptr;
+        __buf_ = __f.__buf_;
+        __invoker_ = __f.__invoker_;
+        __policy_ = __f.__policy_;
+        __f.__policy_ = __policy::__create_empty();
+        __f.__invoker_ = __invoker();
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __policy_func& operator=(nullptr_t)
+    {
+        const __policy* __p = __policy_;
+        __policy_ = __policy::__create_empty();
+        __invoker_ = __invoker();
+        if (__p->__destroy)
+            __p->__destroy(__buf_.__large);
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Rp operator()(_ArgTypes&&... __args) const
+    {
+        return __invoker_.__call_(_VSTD::addressof(__buf_),
+                                  _VSTD::forward<_ArgTypes>(__args)...);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(__policy_func& __f)
+    {
+        _VSTD::swap(__invoker_, __f.__invoker_);
+        _VSTD::swap(__policy_, __f.__policy_);
+        _VSTD::swap(__buf_, __f.__buf_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit operator bool() const _NOEXCEPT
+    {
+        return !__policy_->__is_null;
+    }
+
+#ifndef _LIBCPP_NO_RTTI
+    _LIBCPP_INLINE_VISIBILITY
+    const std::type_info& target_type() const _NOEXCEPT
+    {
+        return *__policy_->__type_info;
+    }
+
+    template <typename _Tp>
+    _LIBCPP_INLINE_VISIBILITY const _Tp* target() const _NOEXCEPT
+    {
+        if (__policy_->__is_null || typeid(_Tp) != *__policy_->__type_info)
+            return nullptr;
+        if (__policy_->__clone) // Out of line storage.
+            return reinterpret_cast<const _Tp*>(__buf_.__large);
+        else
+            return reinterpret_cast<const _Tp*>(&__buf_.__small);
+    }
+#endif // _LIBCPP_NO_RTTI
+};
+
+#if defined(_LIBCPP_HAS_BLOCKS_RUNTIME) && !defined(_LIBCPP_HAS_OBJC_ARC)
+
+extern "C" void *_Block_copy(const void *);
+extern "C" void _Block_release(const void *);
+
+template<class _Rp1, class ..._ArgTypes1, class _Alloc, class _Rp, class ..._ArgTypes>
+class __func<_Rp1(^)(_ArgTypes1...), _Alloc, _Rp(_ArgTypes...)>
+    : public  __base<_Rp(_ArgTypes...)>
+{
+    typedef _Rp1(^__block_type)(_ArgTypes1...);
+    __block_type __f_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __func(__block_type const& __f)
+        : __f_(reinterpret_cast<__block_type>(__f ? _Block_copy(__f) : nullptr))
+    { }
+
+    // [TODO] add && to save on a retain
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __func(__block_type __f, const _Alloc& /* unused */)
+        : __f_(reinterpret_cast<__block_type>(__f ? _Block_copy(__f) : nullptr))
+    { }
+
+    virtual __base<_Rp(_ArgTypes...)>* __clone() const {
+        _LIBCPP_ASSERT(false,
+            "Block pointers are just pointers, so they should always fit into "
+            "std::function's small buffer optimization. This function should "
+            "never be invoked.");
+        return nullptr;
+    }
+
+    virtual void __clone(__base<_Rp(_ArgTypes...)>* __p) const {
+        ::new ((void*)__p) __func(__f_);
+    }
+
+    virtual void destroy() _NOEXCEPT {
+        if (__f_)
+            _Block_release(__f_);
+        __f_ = 0;
+    }
+
+    virtual void destroy_deallocate() _NOEXCEPT {
+        _LIBCPP_ASSERT(false,
+            "Block pointers are just pointers, so they should always fit into "
+            "std::function's small buffer optimization. This function should "
+            "never be invoked.");
+    }
+
+    virtual _Rp operator()(_ArgTypes&& ... __arg) {
+        return _VSTD::__invoke(__f_, _VSTD::forward<_ArgTypes>(__arg)...);
+    }
+
+#ifndef _LIBCPP_NO_RTTI
+    virtual const void* target(type_info const& __ti) const _NOEXCEPT {
+        if (__ti == typeid(__func::__block_type))
+            return &__f_;
+        return (const void*)nullptr;
+    }
+
+    virtual const std::type_info& target_type() const _NOEXCEPT {
+        return typeid(__func::__block_type);
+    }
+#endif // _LIBCPP_NO_RTTI
+};
+
+#endif // _LIBCPP_HAS_EXTENSION_BLOCKS && !_LIBCPP_HAS_OBJC_ARC
+
+}  // __function
+
+template<class _Rp, class ..._ArgTypes>
+class _LIBCPP_TEMPLATE_VIS function<_Rp(_ArgTypes...)>
+#if _LIBCPP_STD_VER <= 17 || !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public __function::__maybe_derive_from_unary_function<_Rp(_ArgTypes...)>,
+      public __function::__maybe_derive_from_binary_function<_Rp(_ArgTypes...)>
+#endif
+{
+#ifndef _LIBCPP_ABI_OPTIMIZED_FUNCTION
+    typedef __function::__value_func<_Rp(_ArgTypes...)> __func;
+#else
+    typedef __function::__policy_func<_Rp(_ArgTypes...)> __func;
+#endif
+
+    __func __f_;
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4348 )
+#endif
+    template <class _Fp, bool = _And<
+        _IsNotSame<__uncvref_t<_Fp>, function>,
+        __invokable<_Fp, _ArgTypes...>
+    >::value>
+    struct __callable;
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+    template <class _Fp>
+        struct __callable<_Fp, true>
+        {
+            static const bool value = is_void<_Rp>::value ||
+                __is_core_convertible<typename __invoke_of<_Fp, _ArgTypes...>::type,
+                                      _Rp>::value;
+        };
+    template <class _Fp>
+        struct __callable<_Fp, false>
+        {
+            static const bool value = false;
+        };
+
+  template <class _Fp>
+  using _EnableIfLValueCallable = typename enable_if<__callable<_Fp&>::value>::type;
+public:
+    typedef _Rp result_type;
+
+    // construct/copy/destroy:
+    _LIBCPP_INLINE_VISIBILITY
+    function() _NOEXCEPT { }
+    _LIBCPP_INLINE_VISIBILITY
+    function(nullptr_t) _NOEXCEPT {}
+    function(const function&);
+    function(function&&) _NOEXCEPT;
+    template<class _Fp, class = _EnableIfLValueCallable<_Fp>>
+    function(_Fp);
+
+#if _LIBCPP_STD_VER <= 14
+    template<class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      function(allocator_arg_t, const _Alloc&) _NOEXCEPT {}
+    template<class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      function(allocator_arg_t, const _Alloc&, nullptr_t) _NOEXCEPT {}
+    template<class _Alloc>
+      function(allocator_arg_t, const _Alloc&, const function&);
+    template<class _Alloc>
+      function(allocator_arg_t, const _Alloc&, function&&);
+    template<class _Fp, class _Alloc, class = _EnableIfLValueCallable<_Fp>>
+      function(allocator_arg_t, const _Alloc& __a, _Fp __f);
+#endif
+
+    function& operator=(const function&);
+    function& operator=(function&&) _NOEXCEPT;
+    function& operator=(nullptr_t) _NOEXCEPT;
+    template<class _Fp, class = _EnableIfLValueCallable<typename decay<_Fp>::type>>
+    function& operator=(_Fp&&);
+
+    ~function();
+
+    // function modifiers:
+    void swap(function&) _NOEXCEPT;
+
+#if _LIBCPP_STD_VER <= 14
+    template<class _Fp, class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      void assign(_Fp&& __f, const _Alloc& __a)
+        {function(allocator_arg, __a, _VSTD::forward<_Fp>(__f)).swap(*this);}
+#endif
+
+    // function capacity:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit operator bool() const _NOEXCEPT {
+      return static_cast<bool>(__f_);
+    }
+
+    // deleted overloads close possible hole in the type system
+    template<class _R2, class... _ArgTypes2>
+      bool operator==(const function<_R2(_ArgTypes2...)>&) const = delete;
+    template<class _R2, class... _ArgTypes2>
+      bool operator!=(const function<_R2(_ArgTypes2...)>&) const = delete;
+public:
+    // function invocation:
+    _Rp operator()(_ArgTypes...) const;
+
+#ifndef _LIBCPP_NO_RTTI
+    // function target access:
+    const std::type_info& target_type() const _NOEXCEPT;
+    template <typename _Tp> _Tp* target() _NOEXCEPT;
+    template <typename _Tp> const _Tp* target() const _NOEXCEPT;
+#endif // _LIBCPP_NO_RTTI
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _Rp, class ..._Ap>
+function(_Rp(*)(_Ap...)) -> function<_Rp(_Ap...)>;
+
+template<class _Fp>
+struct __strip_signature;
+
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...)> { using type = _Rp(_Ap...); };
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) const> { using type = _Rp(_Ap...); };
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) volatile> { using type = _Rp(_Ap...); };
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) const volatile> { using type = _Rp(_Ap...); };
+
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) &> { using type = _Rp(_Ap...); };
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) const &> { using type = _Rp(_Ap...); };
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) volatile &> { using type = _Rp(_Ap...); };
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) const volatile &> { using type = _Rp(_Ap...); };
+
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) noexcept> { using type = _Rp(_Ap...); };
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) const noexcept> { using type = _Rp(_Ap...); };
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) volatile noexcept> { using type = _Rp(_Ap...); };
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) const volatile noexcept> { using type = _Rp(_Ap...); };
+
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) & noexcept> { using type = _Rp(_Ap...); };
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) const & noexcept> { using type = _Rp(_Ap...); };
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) volatile & noexcept> { using type = _Rp(_Ap...); };
+template<class _Rp, class _Gp, class ..._Ap>
+struct __strip_signature<_Rp (_Gp::*) (_Ap...) const volatile & noexcept> { using type = _Rp(_Ap...); };
+
+template<class _Fp, class _Stripped = typename __strip_signature<decltype(&_Fp::operator())>::type>
+function(_Fp) -> function<_Stripped>;
+#endif // _LIBCPP_STD_VER >= 17
+
+template<class _Rp, class ..._ArgTypes>
+function<_Rp(_ArgTypes...)>::function(const function& __f) : __f_(__f.__f_) {}
+
+#if _LIBCPP_STD_VER <= 14
+template<class _Rp, class ..._ArgTypes>
+template <class _Alloc>
+function<_Rp(_ArgTypes...)>::function(allocator_arg_t, const _Alloc&,
+                                     const function& __f) : __f_(__f.__f_) {}
+#endif
+
+template <class _Rp, class... _ArgTypes>
+function<_Rp(_ArgTypes...)>::function(function&& __f) _NOEXCEPT
+    : __f_(_VSTD::move(__f.__f_)) {}
+
+#if _LIBCPP_STD_VER <= 14
+template<class _Rp, class ..._ArgTypes>
+template <class _Alloc>
+function<_Rp(_ArgTypes...)>::function(allocator_arg_t, const _Alloc&,
+                                      function&& __f)
+    : __f_(_VSTD::move(__f.__f_)) {}
+#endif
+
+template <class _Rp, class... _ArgTypes>
+template <class _Fp, class>
+function<_Rp(_ArgTypes...)>::function(_Fp __f) : __f_(_VSTD::move(__f)) {}
+
+#if _LIBCPP_STD_VER <= 14
+template <class _Rp, class... _ArgTypes>
+template <class _Fp, class _Alloc, class>
+function<_Rp(_ArgTypes...)>::function(allocator_arg_t, const _Alloc& __a,
+                                      _Fp __f)
+    : __f_(_VSTD::move(__f), __a) {}
+#endif
+
+template<class _Rp, class ..._ArgTypes>
+function<_Rp(_ArgTypes...)>&
+function<_Rp(_ArgTypes...)>::operator=(const function& __f)
+{
+    function(__f).swap(*this);
+    return *this;
+}
+
+template<class _Rp, class ..._ArgTypes>
+function<_Rp(_ArgTypes...)>&
+function<_Rp(_ArgTypes...)>::operator=(function&& __f) _NOEXCEPT
+{
+    __f_ = _VSTD::move(__f.__f_);
+    return *this;
+}
+
+template<class _Rp, class ..._ArgTypes>
+function<_Rp(_ArgTypes...)>&
+function<_Rp(_ArgTypes...)>::operator=(nullptr_t) _NOEXCEPT
+{
+    __f_ = nullptr;
+    return *this;
+}
+
+template<class _Rp, class ..._ArgTypes>
+template <class _Fp, class>
+function<_Rp(_ArgTypes...)>&
+function<_Rp(_ArgTypes...)>::operator=(_Fp&& __f)
+{
+    function(_VSTD::forward<_Fp>(__f)).swap(*this);
+    return *this;
+}
+
+template<class _Rp, class ..._ArgTypes>
+function<_Rp(_ArgTypes...)>::~function() {}
+
+template<class _Rp, class ..._ArgTypes>
+void
+function<_Rp(_ArgTypes...)>::swap(function& __f) _NOEXCEPT
+{
+    __f_.swap(__f.__f_);
+}
+
+template<class _Rp, class ..._ArgTypes>
+_Rp
+function<_Rp(_ArgTypes...)>::operator()(_ArgTypes... __arg) const
+{
+    return __f_(_VSTD::forward<_ArgTypes>(__arg)...);
+}
+
+#ifndef _LIBCPP_NO_RTTI
+
+template<class _Rp, class ..._ArgTypes>
+const std::type_info&
+function<_Rp(_ArgTypes...)>::target_type() const _NOEXCEPT
+{
+    return __f_.target_type();
+}
+
+template<class _Rp, class ..._ArgTypes>
+template <typename _Tp>
+_Tp*
+function<_Rp(_ArgTypes...)>::target() _NOEXCEPT
+{
+    return (_Tp*)(__f_.template target<_Tp>());
+}
+
+template<class _Rp, class ..._ArgTypes>
+template <typename _Tp>
+const _Tp*
+function<_Rp(_ArgTypes...)>::target() const _NOEXCEPT
+{
+    return __f_.template target<_Tp>();
+}
+
+#endif // _LIBCPP_NO_RTTI
+
+template <class _Rp, class... _ArgTypes>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const function<_Rp(_ArgTypes...)>& __f, nullptr_t) _NOEXCEPT {return !__f;}
+
+template <class _Rp, class... _ArgTypes>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(nullptr_t, const function<_Rp(_ArgTypes...)>& __f) _NOEXCEPT {return !__f;}
+
+template <class _Rp, class... _ArgTypes>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const function<_Rp(_ArgTypes...)>& __f, nullptr_t) _NOEXCEPT {return (bool)__f;}
+
+template <class _Rp, class... _ArgTypes>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(nullptr_t, const function<_Rp(_ArgTypes...)>& __f) _NOEXCEPT {return (bool)__f;}
+
+template <class _Rp, class... _ArgTypes>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(function<_Rp(_ArgTypes...)>& __x, function<_Rp(_ArgTypes...)>& __y) _NOEXCEPT
+{return __x.swap(__y);}
+
+#else // _LIBCPP_CXX03_LANG
+
+namespace __function {
+
+template<class _Fp> class __base;
+
+template<class _Rp>
+class __base<_Rp()>
+{
+    __base(const __base&);
+    __base& operator=(const __base&);
+public:
+    __base() {}
+    virtual ~__base() {}
+    virtual __base* __clone() const = 0;
+    virtual void __clone(__base*) const = 0;
+    virtual void destroy() = 0;
+    virtual void destroy_deallocate() = 0;
+    virtual _Rp operator()() = 0;
+#ifndef _LIBCPP_NO_RTTI
+    virtual const void* target(const type_info&) const = 0;
+    virtual const std::type_info& target_type() const = 0;
+#endif // _LIBCPP_NO_RTTI
+};
+
+template<class _Rp, class _A0>
+class __base<_Rp(_A0)>
+{
+    __base(const __base&);
+    __base& operator=(const __base&);
+public:
+    __base() {}
+    virtual ~__base() {}
+    virtual __base* __clone() const = 0;
+    virtual void __clone(__base*) const = 0;
+    virtual void destroy() = 0;
+    virtual void destroy_deallocate() = 0;
+    virtual _Rp operator()(_A0) = 0;
+#ifndef _LIBCPP_NO_RTTI
+    virtual const void* target(const type_info&) const = 0;
+    virtual const std::type_info& target_type() const = 0;
+#endif // _LIBCPP_NO_RTTI
+};
+
+template<class _Rp, class _A0, class _A1>
+class __base<_Rp(_A0, _A1)>
+{
+    __base(const __base&);
+    __base& operator=(const __base&);
+public:
+    __base() {}
+    virtual ~__base() {}
+    virtual __base* __clone() const = 0;
+    virtual void __clone(__base*) const = 0;
+    virtual void destroy() = 0;
+    virtual void destroy_deallocate() = 0;
+    virtual _Rp operator()(_A0, _A1) = 0;
+#ifndef _LIBCPP_NO_RTTI
+    virtual const void* target(const type_info&) const = 0;
+    virtual const std::type_info& target_type() const = 0;
+#endif // _LIBCPP_NO_RTTI
+};
+
+template<class _Rp, class _A0, class _A1, class _A2>
+class __base<_Rp(_A0, _A1, _A2)>
+{
+    __base(const __base&);
+    __base& operator=(const __base&);
+public:
+    __base() {}
+    virtual ~__base() {}
+    virtual __base* __clone() const = 0;
+    virtual void __clone(__base*) const = 0;
+    virtual void destroy() = 0;
+    virtual void destroy_deallocate() = 0;
+    virtual _Rp operator()(_A0, _A1, _A2) = 0;
+#ifndef _LIBCPP_NO_RTTI
+    virtual const void* target(const type_info&) const = 0;
+    virtual const std::type_info& target_type() const = 0;
+#endif // _LIBCPP_NO_RTTI
+};
+
+template<class _FD, class _Alloc, class _FB> class __func;
+
+template<class _Fp, class _Alloc, class _Rp>
+class __func<_Fp, _Alloc, _Rp()>
+    : public  __base<_Rp()>
+{
+    __compressed_pair<_Fp, _Alloc> __f_;
+public:
+    explicit __func(_Fp __f) : __f_(_VSTD::move(__f), __default_init_tag()) {}
+    explicit __func(_Fp __f, _Alloc __a) : __f_(_VSTD::move(__f), _VSTD::move(__a)) {}
+    virtual __base<_Rp()>* __clone() const;
+    virtual void __clone(__base<_Rp()>*) const;
+    virtual void destroy();
+    virtual void destroy_deallocate();
+    virtual _Rp operator()();
+#ifndef _LIBCPP_NO_RTTI
+    virtual const void* target(const type_info&) const;
+    virtual const std::type_info& target_type() const;
+#endif // _LIBCPP_NO_RTTI
+};
+
+template<class _Fp, class _Alloc, class _Rp>
+__base<_Rp()>*
+__func<_Fp, _Alloc, _Rp()>::__clone() const
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    typedef typename __rebind_alloc_helper<__alloc_traits, __func>::type _Ap;
+    _Ap __a(__f_.second());
+    typedef __allocator_destructor<_Ap> _Dp;
+    unique_ptr<__func, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+    ::new ((void*)__hold.get()) __func(__f_.first(), _Alloc(__a));
+    return __hold.release();
+}
+
+template<class _Fp, class _Alloc, class _Rp>
+void
+__func<_Fp, _Alloc, _Rp()>::__clone(__base<_Rp()>* __p) const
+{
+    ::new ((void*)__p) __func(__f_.first(), __f_.second());
+}
+
+template<class _Fp, class _Alloc, class _Rp>
+void
+__func<_Fp, _Alloc, _Rp()>::destroy()
+{
+    __f_.~__compressed_pair<_Fp, _Alloc>();
+}
+
+template<class _Fp, class _Alloc, class _Rp>
+void
+__func<_Fp, _Alloc, _Rp()>::destroy_deallocate()
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    typedef typename __rebind_alloc_helper<__alloc_traits, __func>::type _Ap;
+    _Ap __a(__f_.second());
+    __f_.~__compressed_pair<_Fp, _Alloc>();
+    __a.deallocate(this, 1);
+}
+
+template<class _Fp, class _Alloc, class _Rp>
+_Rp
+__func<_Fp, _Alloc, _Rp()>::operator()()
+{
+    typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+    return _Invoker::__call(__f_.first());
+}
+
+#ifndef _LIBCPP_NO_RTTI
+
+template<class _Fp, class _Alloc, class _Rp>
+const void*
+__func<_Fp, _Alloc, _Rp()>::target(const type_info& __ti) const
+{
+    if (__ti == typeid(_Fp))
+        return &__f_.first();
+    return (const void*)0;
+}
+
+template<class _Fp, class _Alloc, class _Rp>
+const std::type_info&
+__func<_Fp, _Alloc, _Rp()>::target_type() const
+{
+    return typeid(_Fp);
+}
+
+#endif // _LIBCPP_NO_RTTI
+
+template<class _Fp, class _Alloc, class _Rp, class _A0>
+class __func<_Fp, _Alloc, _Rp(_A0)>
+    : public  __base<_Rp(_A0)>
+{
+    __compressed_pair<_Fp, _Alloc> __f_;
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit __func(_Fp __f) : __f_(_VSTD::move(__f), __default_init_tag()) {}
+    _LIBCPP_INLINE_VISIBILITY explicit __func(_Fp __f, _Alloc __a)
+        : __f_(_VSTD::move(__f), _VSTD::move(__a)) {}
+    virtual __base<_Rp(_A0)>* __clone() const;
+    virtual void __clone(__base<_Rp(_A0)>*) const;
+    virtual void destroy();
+    virtual void destroy_deallocate();
+    virtual _Rp operator()(_A0);
+#ifndef _LIBCPP_NO_RTTI
+    virtual const void* target(const type_info&) const;
+    virtual const std::type_info& target_type() const;
+#endif // _LIBCPP_NO_RTTI
+};
+
+template<class _Fp, class _Alloc, class _Rp, class _A0>
+__base<_Rp(_A0)>*
+__func<_Fp, _Alloc, _Rp(_A0)>::__clone() const
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    typedef typename __rebind_alloc_helper<__alloc_traits, __func>::type _Ap;
+    _Ap __a(__f_.second());
+    typedef __allocator_destructor<_Ap> _Dp;
+    unique_ptr<__func, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+    ::new ((void*)__hold.get()) __func(__f_.first(), _Alloc(__a));
+    return __hold.release();
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0>
+void
+__func<_Fp, _Alloc, _Rp(_A0)>::__clone(__base<_Rp(_A0)>* __p) const
+{
+    ::new ((void*)__p) __func(__f_.first(), __f_.second());
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0>
+void
+__func<_Fp, _Alloc, _Rp(_A0)>::destroy()
+{
+    __f_.~__compressed_pair<_Fp, _Alloc>();
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0>
+void
+__func<_Fp, _Alloc, _Rp(_A0)>::destroy_deallocate()
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    typedef typename __rebind_alloc_helper<__alloc_traits, __func>::type _Ap;
+    _Ap __a(__f_.second());
+    __f_.~__compressed_pair<_Fp, _Alloc>();
+    __a.deallocate(this, 1);
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0>
+_Rp
+__func<_Fp, _Alloc, _Rp(_A0)>::operator()(_A0 __a0)
+{
+    typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+    return _Invoker::__call(__f_.first(), __a0);
+}
+
+#ifndef _LIBCPP_NO_RTTI
+
+template<class _Fp, class _Alloc, class _Rp, class _A0>
+const void*
+__func<_Fp, _Alloc, _Rp(_A0)>::target(const type_info& __ti) const
+{
+    if (__ti == typeid(_Fp))
+        return &__f_.first();
+    return (const void*)0;
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0>
+const std::type_info&
+__func<_Fp, _Alloc, _Rp(_A0)>::target_type() const
+{
+    return typeid(_Fp);
+}
+
+#endif // _LIBCPP_NO_RTTI
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1>
+class __func<_Fp, _Alloc, _Rp(_A0, _A1)>
+    : public  __base<_Rp(_A0, _A1)>
+{
+    __compressed_pair<_Fp, _Alloc> __f_;
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit __func(_Fp __f) : __f_(_VSTD::move(__f), __default_init_tag()) {}
+    _LIBCPP_INLINE_VISIBILITY explicit __func(_Fp __f, _Alloc __a)
+        : __f_(_VSTD::move(__f), _VSTD::move(__a)) {}
+    virtual __base<_Rp(_A0, _A1)>* __clone() const;
+    virtual void __clone(__base<_Rp(_A0, _A1)>*) const;
+    virtual void destroy();
+    virtual void destroy_deallocate();
+    virtual _Rp operator()(_A0, _A1);
+#ifndef _LIBCPP_NO_RTTI
+    virtual const void* target(const type_info&) const;
+    virtual const std::type_info& target_type() const;
+#endif // _LIBCPP_NO_RTTI
+};
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1>
+__base<_Rp(_A0, _A1)>*
+__func<_Fp, _Alloc, _Rp(_A0, _A1)>::__clone() const
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    typedef typename __rebind_alloc_helper<__alloc_traits, __func>::type _Ap;
+    _Ap __a(__f_.second());
+    typedef __allocator_destructor<_Ap> _Dp;
+    unique_ptr<__func, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+    ::new ((void*)__hold.get()) __func(__f_.first(), _Alloc(__a));
+    return __hold.release();
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1>
+void
+__func<_Fp, _Alloc, _Rp(_A0, _A1)>::__clone(__base<_Rp(_A0, _A1)>* __p) const
+{
+    ::new ((void*)__p) __func(__f_.first(), __f_.second());
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1>
+void
+__func<_Fp, _Alloc, _Rp(_A0, _A1)>::destroy()
+{
+    __f_.~__compressed_pair<_Fp, _Alloc>();
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1>
+void
+__func<_Fp, _Alloc, _Rp(_A0, _A1)>::destroy_deallocate()
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    typedef typename __rebind_alloc_helper<__alloc_traits, __func>::type _Ap;
+    _Ap __a(__f_.second());
+    __f_.~__compressed_pair<_Fp, _Alloc>();
+    __a.deallocate(this, 1);
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1>
+_Rp
+__func<_Fp, _Alloc, _Rp(_A0, _A1)>::operator()(_A0 __a0, _A1 __a1)
+{
+    typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+    return _Invoker::__call(__f_.first(), __a0, __a1);
+}
+
+#ifndef _LIBCPP_NO_RTTI
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1>
+const void*
+__func<_Fp, _Alloc, _Rp(_A0, _A1)>::target(const type_info& __ti) const
+{
+    if (__ti == typeid(_Fp))
+        return &__f_.first();
+    return (const void*)0;
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1>
+const std::type_info&
+__func<_Fp, _Alloc, _Rp(_A0, _A1)>::target_type() const
+{
+    return typeid(_Fp);
+}
+
+#endif // _LIBCPP_NO_RTTI
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1, class _A2>
+class __func<_Fp, _Alloc, _Rp(_A0, _A1, _A2)>
+    : public  __base<_Rp(_A0, _A1, _A2)>
+{
+    __compressed_pair<_Fp, _Alloc> __f_;
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit __func(_Fp __f) : __f_(_VSTD::move(__f), __default_init_tag()) {}
+    _LIBCPP_INLINE_VISIBILITY explicit __func(_Fp __f, _Alloc __a)
+        : __f_(_VSTD::move(__f), _VSTD::move(__a)) {}
+    virtual __base<_Rp(_A0, _A1, _A2)>* __clone() const;
+    virtual void __clone(__base<_Rp(_A0, _A1, _A2)>*) const;
+    virtual void destroy();
+    virtual void destroy_deallocate();
+    virtual _Rp operator()(_A0, _A1, _A2);
+#ifndef _LIBCPP_NO_RTTI
+    virtual const void* target(const type_info&) const;
+    virtual const std::type_info& target_type() const;
+#endif // _LIBCPP_NO_RTTI
+};
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1, class _A2>
+__base<_Rp(_A0, _A1, _A2)>*
+__func<_Fp, _Alloc, _Rp(_A0, _A1, _A2)>::__clone() const
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    typedef typename __rebind_alloc_helper<__alloc_traits, __func>::type _Ap;
+    _Ap __a(__f_.second());
+    typedef __allocator_destructor<_Ap> _Dp;
+    unique_ptr<__func, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+    ::new ((void*)__hold.get()) __func(__f_.first(), _Alloc(__a));
+    return __hold.release();
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1, class _A2>
+void
+__func<_Fp, _Alloc, _Rp(_A0, _A1, _A2)>::__clone(__base<_Rp(_A0, _A1, _A2)>* __p) const
+{
+    ::new ((void*)__p) __func(__f_.first(), __f_.second());
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1, class _A2>
+void
+__func<_Fp, _Alloc, _Rp(_A0, _A1, _A2)>::destroy()
+{
+    __f_.~__compressed_pair<_Fp, _Alloc>();
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1, class _A2>
+void
+__func<_Fp, _Alloc, _Rp(_A0, _A1, _A2)>::destroy_deallocate()
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    typedef typename __rebind_alloc_helper<__alloc_traits, __func>::type _Ap;
+    _Ap __a(__f_.second());
+    __f_.~__compressed_pair<_Fp, _Alloc>();
+    __a.deallocate(this, 1);
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1, class _A2>
+_Rp
+__func<_Fp, _Alloc, _Rp(_A0, _A1, _A2)>::operator()(_A0 __a0, _A1 __a1, _A2 __a2)
+{
+    typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+    return _Invoker::__call(__f_.first(), __a0, __a1, __a2);
+}
+
+#ifndef _LIBCPP_NO_RTTI
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1, class _A2>
+const void*
+__func<_Fp, _Alloc, _Rp(_A0, _A1, _A2)>::target(const type_info& __ti) const
+{
+    if (__ti == typeid(_Fp))
+        return &__f_.first();
+    return (const void*)0;
+}
+
+template<class _Fp, class _Alloc, class _Rp, class _A0, class _A1, class _A2>
+const std::type_info&
+__func<_Fp, _Alloc, _Rp(_A0, _A1, _A2)>::target_type() const
+{
+    return typeid(_Fp);
+}
+
+#endif // _LIBCPP_NO_RTTI
+
+}  // __function
+
+template<class _Rp>
+class _LIBCPP_TEMPLATE_VIS function<_Rp()>
+{
+    typedef __function::__base<_Rp()> __base;
+    aligned_storage<3*sizeof(void*)>::type __buf_;
+    __base* __f_;
+
+public:
+    typedef _Rp result_type;
+
+    // 20.7.16.2.1, construct/copy/destroy:
+    _LIBCPP_INLINE_VISIBILITY explicit function() : __f_(0) {}
+    _LIBCPP_INLINE_VISIBILITY function(nullptr_t) : __f_(0) {}
+    function(const function&);
+    template<class _Fp>
+      function(_Fp,
+               typename enable_if<!is_integral<_Fp>::value>::type* = 0);
+
+    template<class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      function(allocator_arg_t, const _Alloc&) : __f_(0) {}
+    template<class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      function(allocator_arg_t, const _Alloc&, nullptr_t) : __f_(0) {}
+    template<class _Alloc>
+      function(allocator_arg_t, const _Alloc&, const function&);
+    template<class _Fp, class _Alloc>
+      function(allocator_arg_t, const _Alloc& __a, _Fp __f,
+               typename enable_if<!is_integral<_Fp>::value>::type* = 0);
+
+    function& operator=(const function&);
+    function& operator=(nullptr_t);
+    template<class _Fp>
+      typename enable_if
+      <
+        !is_integral<_Fp>::value,
+        function&
+      >::type
+      operator=(_Fp);
+
+    ~function();
+
+    // 20.7.16.2.2, function modifiers:
+    void swap(function&);
+    template<class _Fp, class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      void assign(_Fp __f, const _Alloc& __a)
+        {function(allocator_arg, __a, __f).swap(*this);}
+
+    // 20.7.16.2.3, function capacity:
+    _LIBCPP_INLINE_VISIBILITY explicit operator bool() const {return __f_;}
+
+private:
+    // deleted overloads close possible hole in the type system
+    template<class _R2>
+      bool operator==(const function<_R2()>&) const;// = delete;
+    template<class _R2>
+      bool operator!=(const function<_R2()>&) const;// = delete;
+public:
+    // 20.7.16.2.4, function invocation:
+    _Rp operator()() const;
+
+#ifndef _LIBCPP_NO_RTTI
+    // 20.7.16.2.5, function target access:
+    const std::type_info& target_type() const;
+    template <typename _Tp> _Tp* target();
+    template <typename _Tp> const _Tp* target() const;
+#endif // _LIBCPP_NO_RTTI
+};
+
+template<class _Rp>
+function<_Rp()>::function(const function& __f)
+{
+    if (__f.__f_ == 0)
+        __f_ = 0;
+    else if (__f.__f_ == (const __base*)&__f.__buf_)
+    {
+        __f_ = (__base*)&__buf_;
+        __f.__f_->__clone(__f_);
+    }
+    else
+        __f_ = __f.__f_->__clone();
+}
+
+template<class _Rp>
+template<class _Alloc>
+function<_Rp()>::function(allocator_arg_t, const _Alloc&, const function& __f)
+{
+    if (__f.__f_ == 0)
+        __f_ = 0;
+    else if (__f.__f_ == (const __base*)&__f.__buf_)
+    {
+        __f_ = (__base*)&__buf_;
+        __f.__f_->__clone(__f_);
+    }
+    else
+        __f_ = __f.__f_->__clone();
+}
+
+template<class _Rp>
+template <class _Fp>
+function<_Rp()>::function(_Fp __f,
+                                     typename enable_if<!is_integral<_Fp>::value>::type*)
+    : __f_(0)
+{
+    if (__function::__not_null(__f))
+    {
+        typedef __function::__func<_Fp, allocator<_Fp>, _Rp()> _FF;
+        if (sizeof(_FF) <= sizeof(__buf_))
+        {
+            __f_ = (__base*)&__buf_;
+            ::new ((void*)__f_) _FF(__f);
+        }
+        else
+        {
+            typedef allocator<_FF> _Ap;
+            _Ap __a;
+            typedef __allocator_destructor<_Ap> _Dp;
+            unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+            ::new ((void*)__hold.get()) _FF(__f, allocator<_Fp>(__a));
+            __f_ = __hold.release();
+        }
+    }
+}
+
+template<class _Rp>
+template <class _Fp, class _Alloc>
+function<_Rp()>::function(allocator_arg_t, const _Alloc& __a0, _Fp __f,
+                                     typename enable_if<!is_integral<_Fp>::value>::type*)
+    : __f_(0)
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    if (__function::__not_null(__f))
+    {
+        typedef __function::__func<_Fp, _Alloc, _Rp()> _FF;
+        if (sizeof(_FF) <= sizeof(__buf_))
+        {
+            __f_ = (__base*)&__buf_;
+            ::new ((void*)__f_) _FF(__f, __a0);
+        }
+        else
+        {
+            typedef typename __rebind_alloc_helper<__alloc_traits, _FF>::type _Ap;
+            _Ap __a(__a0);
+            typedef __allocator_destructor<_Ap> _Dp;
+            unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+            ::new ((void*)__hold.get()) _FF(__f, _Alloc(__a));
+            __f_ = __hold.release();
+        }
+    }
+}
+
+template<class _Rp>
+function<_Rp()>&
+function<_Rp()>::operator=(const function& __f)
+{
+    if (__f)
+        function(__f).swap(*this);
+    else
+        *this = nullptr;
+    return *this;
+}
+
+template<class _Rp>
+function<_Rp()>&
+function<_Rp()>::operator=(nullptr_t)
+{
+    __base* __t = __f_;
+    __f_ = 0;
+    if (__t == (__base*)&__buf_)
+        __t->destroy();
+    else if (__t)
+        __t->destroy_deallocate();
+    return *this;
+}
+
+template<class _Rp>
+template <class _Fp>
+typename enable_if
+<
+    !is_integral<_Fp>::value,
+    function<_Rp()>&
+>::type
+function<_Rp()>::operator=(_Fp __f)
+{
+    function(_VSTD::move(__f)).swap(*this);
+    return *this;
+}
+
+template<class _Rp>
+function<_Rp()>::~function()
+{
+    if (__f_ == (__base*)&__buf_)
+        __f_->destroy();
+    else if (__f_)
+        __f_->destroy_deallocate();
+}
+
+template<class _Rp>
+void
+function<_Rp()>::swap(function& __f)
+{
+    if (_VSTD::addressof(__f) == this)
+      return;
+    if (__f_ == (__base*)&__buf_ && __f.__f_ == (__base*)&__f.__buf_)
+    {
+        typename aligned_storage<sizeof(__buf_)>::type __tempbuf;
+        __base* __t = (__base*)&__tempbuf;
+        __f_->__clone(__t);
+        __f_->destroy();
+        __f_ = 0;
+        __f.__f_->__clone((__base*)&__buf_);
+        __f.__f_->destroy();
+        __f.__f_ = 0;
+        __f_ = (__base*)&__buf_;
+        __t->__clone((__base*)&__f.__buf_);
+        __t->destroy();
+        __f.__f_ = (__base*)&__f.__buf_;
+    }
+    else if (__f_ == (__base*)&__buf_)
+    {
+        __f_->__clone((__base*)&__f.__buf_);
+        __f_->destroy();
+        __f_ = __f.__f_;
+        __f.__f_ = (__base*)&__f.__buf_;
+    }
+    else if (__f.__f_ == (__base*)&__f.__buf_)
+    {
+        __f.__f_->__clone((__base*)&__buf_);
+        __f.__f_->destroy();
+        __f.__f_ = __f_;
+        __f_ = (__base*)&__buf_;
+    }
+    else
+        _VSTD::swap(__f_, __f.__f_);
+}
+
+template<class _Rp>
+_Rp
+function<_Rp()>::operator()() const
+{
+    if (__f_ == 0)
+        __throw_bad_function_call();
+    return (*__f_)();
+}
+
+#ifndef _LIBCPP_NO_RTTI
+
+template<class _Rp>
+const std::type_info&
+function<_Rp()>::target_type() const
+{
+    if (__f_ == 0)
+        return typeid(void);
+    return __f_->target_type();
+}
+
+template<class _Rp>
+template <typename _Tp>
+_Tp*
+function<_Rp()>::target()
+{
+    if (__f_ == 0)
+        return (_Tp*)0;
+    return (_Tp*) const_cast<void *>(__f_->target(typeid(_Tp)));
+}
+
+template<class _Rp>
+template <typename _Tp>
+const _Tp*
+function<_Rp()>::target() const
+{
+    if (__f_ == 0)
+        return (const _Tp*)0;
+    return (const _Tp*)__f_->target(typeid(_Tp));
+}
+
+#endif // _LIBCPP_NO_RTTI
+
+template<class _Rp, class _A0>
+class _LIBCPP_TEMPLATE_VIS function<_Rp(_A0)>
+    : public unary_function<_A0, _Rp>
+{
+    typedef __function::__base<_Rp(_A0)> __base;
+    aligned_storage<3*sizeof(void*)>::type __buf_;
+    __base* __f_;
+
+public:
+    typedef _Rp result_type;
+
+    // 20.7.16.2.1, construct/copy/destroy:
+    _LIBCPP_INLINE_VISIBILITY explicit function() : __f_(0) {}
+    _LIBCPP_INLINE_VISIBILITY function(nullptr_t) : __f_(0) {}
+    function(const function&);
+    template<class _Fp>
+      function(_Fp,
+               typename enable_if<!is_integral<_Fp>::value>::type* = 0);
+
+    template<class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      function(allocator_arg_t, const _Alloc&) : __f_(0) {}
+    template<class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      function(allocator_arg_t, const _Alloc&, nullptr_t) : __f_(0) {}
+    template<class _Alloc>
+      function(allocator_arg_t, const _Alloc&, const function&);
+    template<class _Fp, class _Alloc>
+      function(allocator_arg_t, const _Alloc& __a, _Fp __f,
+               typename enable_if<!is_integral<_Fp>::value>::type* = 0);
+
+    function& operator=(const function&);
+    function& operator=(nullptr_t);
+    template<class _Fp>
+      typename enable_if
+      <
+        !is_integral<_Fp>::value,
+        function&
+      >::type
+      operator=(_Fp);
+
+    ~function();
+
+    // 20.7.16.2.2, function modifiers:
+    void swap(function&);
+    template<class _Fp, class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      void assign(_Fp __f, const _Alloc& __a)
+        {function(allocator_arg, __a, __f).swap(*this);}
+
+    // 20.7.16.2.3, function capacity:
+    _LIBCPP_INLINE_VISIBILITY explicit operator bool() const {return __f_;}
+
+private:
+    // deleted overloads close possible hole in the type system
+    template<class _R2, class _B0>
+      bool operator==(const function<_R2(_B0)>&) const;// = delete;
+    template<class _R2, class _B0>
+      bool operator!=(const function<_R2(_B0)>&) const;// = delete;
+public:
+    // 20.7.16.2.4, function invocation:
+    _Rp operator()(_A0) const;
+
+#ifndef _LIBCPP_NO_RTTI
+    // 20.7.16.2.5, function target access:
+    const std::type_info& target_type() const;
+    template <typename _Tp> _Tp* target();
+    template <typename _Tp> const _Tp* target() const;
+#endif // _LIBCPP_NO_RTTI
+};
+
+template<class _Rp, class _A0>
+function<_Rp(_A0)>::function(const function& __f)
+{
+    if (__f.__f_ == 0)
+        __f_ = 0;
+    else if (__f.__f_ == (const __base*)&__f.__buf_)
+    {
+        __f_ = (__base*)&__buf_;
+        __f.__f_->__clone(__f_);
+    }
+    else
+        __f_ = __f.__f_->__clone();
+}
+
+template<class _Rp, class _A0>
+template<class _Alloc>
+function<_Rp(_A0)>::function(allocator_arg_t, const _Alloc&, const function& __f)
+{
+    if (__f.__f_ == 0)
+        __f_ = 0;
+    else if (__f.__f_ == (const __base*)&__f.__buf_)
+    {
+        __f_ = (__base*)&__buf_;
+        __f.__f_->__clone(__f_);
+    }
+    else
+        __f_ = __f.__f_->__clone();
+}
+
+template<class _Rp, class _A0>
+template <class _Fp>
+function<_Rp(_A0)>::function(_Fp __f,
+                                     typename enable_if<!is_integral<_Fp>::value>::type*)
+    : __f_(0)
+{
+    if (__function::__not_null(__f))
+    {
+        typedef __function::__func<_Fp, allocator<_Fp>, _Rp(_A0)> _FF;
+        if (sizeof(_FF) <= sizeof(__buf_))
+        {
+            __f_ = (__base*)&__buf_;
+            ::new ((void*)__f_) _FF(__f);
+        }
+        else
+        {
+            typedef allocator<_FF> _Ap;
+            _Ap __a;
+            typedef __allocator_destructor<_Ap> _Dp;
+            unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+            ::new ((void*)__hold.get()) _FF(__f, allocator<_Fp>(__a));
+            __f_ = __hold.release();
+        }
+    }
+}
+
+template<class _Rp, class _A0>
+template <class _Fp, class _Alloc>
+function<_Rp(_A0)>::function(allocator_arg_t, const _Alloc& __a0, _Fp __f,
+                                     typename enable_if<!is_integral<_Fp>::value>::type*)
+    : __f_(0)
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    if (__function::__not_null(__f))
+    {
+        typedef __function::__func<_Fp, _Alloc, _Rp(_A0)> _FF;
+        if (sizeof(_FF) <= sizeof(__buf_))
+        {
+            __f_ = (__base*)&__buf_;
+            ::new ((void*)__f_) _FF(__f, __a0);
+        }
+        else
+        {
+            typedef typename __rebind_alloc_helper<__alloc_traits, _FF>::type _Ap;
+            _Ap __a(__a0);
+            typedef __allocator_destructor<_Ap> _Dp;
+            unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+            ::new ((void*)__hold.get()) _FF(__f, _Alloc(__a));
+            __f_ = __hold.release();
+        }
+    }
+}
+
+template<class _Rp, class _A0>
+function<_Rp(_A0)>&
+function<_Rp(_A0)>::operator=(const function& __f)
+{
+    if (__f)
+        function(__f).swap(*this);
+    else
+        *this = nullptr;
+    return *this;
+}
+
+template<class _Rp, class _A0>
+function<_Rp(_A0)>&
+function<_Rp(_A0)>::operator=(nullptr_t)
+{
+    __base* __t = __f_;
+    __f_ = 0;
+    if (__t == (__base*)&__buf_)
+        __t->destroy();
+    else if (__t)
+        __t->destroy_deallocate();
+    return *this;
+}
+
+template<class _Rp, class _A0>
+template <class _Fp>
+typename enable_if
+<
+    !is_integral<_Fp>::value,
+    function<_Rp(_A0)>&
+>::type
+function<_Rp(_A0)>::operator=(_Fp __f)
+{
+    function(_VSTD::move(__f)).swap(*this);
+    return *this;
+}
+
+template<class _Rp, class _A0>
+function<_Rp(_A0)>::~function()
+{
+    if (__f_ == (__base*)&__buf_)
+        __f_->destroy();
+    else if (__f_)
+        __f_->destroy_deallocate();
+}
+
+template<class _Rp, class _A0>
+void
+function<_Rp(_A0)>::swap(function& __f)
+{
+    if (_VSTD::addressof(__f) == this)
+      return;
+    if (__f_ == (__base*)&__buf_ && __f.__f_ == (__base*)&__f.__buf_)
+    {
+        typename aligned_storage<sizeof(__buf_)>::type __tempbuf;
+        __base* __t = (__base*)&__tempbuf;
+        __f_->__clone(__t);
+        __f_->destroy();
+        __f_ = 0;
+        __f.__f_->__clone((__base*)&__buf_);
+        __f.__f_->destroy();
+        __f.__f_ = 0;
+        __f_ = (__base*)&__buf_;
+        __t->__clone((__base*)&__f.__buf_);
+        __t->destroy();
+        __f.__f_ = (__base*)&__f.__buf_;
+    }
+    else if (__f_ == (__base*)&__buf_)
+    {
+        __f_->__clone((__base*)&__f.__buf_);
+        __f_->destroy();
+        __f_ = __f.__f_;
+        __f.__f_ = (__base*)&__f.__buf_;
+    }
+    else if (__f.__f_ == (__base*)&__f.__buf_)
+    {
+        __f.__f_->__clone((__base*)&__buf_);
+        __f.__f_->destroy();
+        __f.__f_ = __f_;
+        __f_ = (__base*)&__buf_;
+    }
+    else
+        _VSTD::swap(__f_, __f.__f_);
+}
+
+template<class _Rp, class _A0>
+_Rp
+function<_Rp(_A0)>::operator()(_A0 __a0) const
+{
+    if (__f_ == 0)
+        __throw_bad_function_call();
+    return (*__f_)(__a0);
+}
+
+#ifndef _LIBCPP_NO_RTTI
+
+template<class _Rp, class _A0>
+const std::type_info&
+function<_Rp(_A0)>::target_type() const
+{
+    if (__f_ == 0)
+        return typeid(void);
+    return __f_->target_type();
+}
+
+template<class _Rp, class _A0>
+template <typename _Tp>
+_Tp*
+function<_Rp(_A0)>::target()
+{
+    if (__f_ == 0)
+        return (_Tp*)0;
+    return (_Tp*) const_cast<void *>(__f_->target(typeid(_Tp)));
+}
+
+template<class _Rp, class _A0>
+template <typename _Tp>
+const _Tp*
+function<_Rp(_A0)>::target() const
+{
+    if (__f_ == 0)
+        return (const _Tp*)0;
+    return (const _Tp*)__f_->target(typeid(_Tp));
+}
+
+#endif // _LIBCPP_NO_RTTI
+
+template<class _Rp, class _A0, class _A1>
+class _LIBCPP_TEMPLATE_VIS function<_Rp(_A0, _A1)>
+    : public binary_function<_A0, _A1, _Rp>
+{
+    typedef __function::__base<_Rp(_A0, _A1)> __base;
+    aligned_storage<3*sizeof(void*)>::type __buf_;
+    __base* __f_;
+
+public:
+    typedef _Rp result_type;
+
+    // 20.7.16.2.1, construct/copy/destroy:
+    _LIBCPP_INLINE_VISIBILITY explicit function() : __f_(0) {}
+    _LIBCPP_INLINE_VISIBILITY function(nullptr_t) : __f_(0) {}
+    function(const function&);
+    template<class _Fp>
+      function(_Fp,
+               typename enable_if<!is_integral<_Fp>::value>::type* = 0);
+
+    template<class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      function(allocator_arg_t, const _Alloc&) : __f_(0) {}
+    template<class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      function(allocator_arg_t, const _Alloc&, nullptr_t) : __f_(0) {}
+    template<class _Alloc>
+      function(allocator_arg_t, const _Alloc&, const function&);
+    template<class _Fp, class _Alloc>
+      function(allocator_arg_t, const _Alloc& __a, _Fp __f,
+               typename enable_if<!is_integral<_Fp>::value>::type* = 0);
+
+    function& operator=(const function&);
+    function& operator=(nullptr_t);
+    template<class _Fp>
+      typename enable_if
+      <
+        !is_integral<_Fp>::value,
+        function&
+      >::type
+      operator=(_Fp);
+
+    ~function();
+
+    // 20.7.16.2.2, function modifiers:
+    void swap(function&);
+    template<class _Fp, class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      void assign(_Fp __f, const _Alloc& __a)
+        {function(allocator_arg, __a, __f).swap(*this);}
+
+    // 20.7.16.2.3, function capacity:
+    _LIBCPP_INLINE_VISIBILITY explicit operator bool() const {return __f_;}
+
+private:
+    // deleted overloads close possible hole in the type system
+    template<class _R2, class _B0, class _B1>
+      bool operator==(const function<_R2(_B0, _B1)>&) const;// = delete;
+    template<class _R2, class _B0, class _B1>
+      bool operator!=(const function<_R2(_B0, _B1)>&) const;// = delete;
+public:
+    // 20.7.16.2.4, function invocation:
+    _Rp operator()(_A0, _A1) const;
+
+#ifndef _LIBCPP_NO_RTTI
+    // 20.7.16.2.5, function target access:
+    const std::type_info& target_type() const;
+    template <typename _Tp> _Tp* target();
+    template <typename _Tp> const _Tp* target() const;
+#endif // _LIBCPP_NO_RTTI
+};
+
+template<class _Rp, class _A0, class _A1>
+function<_Rp(_A0, _A1)>::function(const function& __f)
+{
+    if (__f.__f_ == 0)
+        __f_ = 0;
+    else if (__f.__f_ == (const __base*)&__f.__buf_)
+    {
+        __f_ = (__base*)&__buf_;
+        __f.__f_->__clone(__f_);
+    }
+    else
+        __f_ = __f.__f_->__clone();
+}
+
+template<class _Rp, class _A0, class _A1>
+template<class _Alloc>
+function<_Rp(_A0, _A1)>::function(allocator_arg_t, const _Alloc&, const function& __f)
+{
+    if (__f.__f_ == 0)
+        __f_ = 0;
+    else if (__f.__f_ == (const __base*)&__f.__buf_)
+    {
+        __f_ = (__base*)&__buf_;
+        __f.__f_->__clone(__f_);
+    }
+    else
+        __f_ = __f.__f_->__clone();
+}
+
+template<class _Rp, class _A0, class _A1>
+template <class _Fp>
+function<_Rp(_A0, _A1)>::function(_Fp __f,
+                                 typename enable_if<!is_integral<_Fp>::value>::type*)
+    : __f_(0)
+{
+    if (__function::__not_null(__f))
+    {
+        typedef __function::__func<_Fp, allocator<_Fp>, _Rp(_A0, _A1)> _FF;
+        if (sizeof(_FF) <= sizeof(__buf_))
+        {
+            __f_ = (__base*)&__buf_;
+            ::new ((void*)__f_) _FF(__f);
+        }
+        else
+        {
+            typedef allocator<_FF> _Ap;
+            _Ap __a;
+            typedef __allocator_destructor<_Ap> _Dp;
+            unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+            ::new ((void*)__hold.get()) _FF(__f, allocator<_Fp>(__a));
+            __f_ = __hold.release();
+        }
+    }
+}
+
+template<class _Rp, class _A0, class _A1>
+template <class _Fp, class _Alloc>
+function<_Rp(_A0, _A1)>::function(allocator_arg_t, const _Alloc& __a0, _Fp __f,
+                                 typename enable_if<!is_integral<_Fp>::value>::type*)
+    : __f_(0)
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    if (__function::__not_null(__f))
+    {
+        typedef __function::__func<_Fp, _Alloc, _Rp(_A0, _A1)> _FF;
+        if (sizeof(_FF) <= sizeof(__buf_))
+        {
+            __f_ = (__base*)&__buf_;
+            ::new ((void*)__f_) _FF(__f, __a0);
+        }
+        else
+        {
+            typedef typename __rebind_alloc_helper<__alloc_traits, _FF>::type _Ap;
+            _Ap __a(__a0);
+            typedef __allocator_destructor<_Ap> _Dp;
+            unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+            ::new ((void*)__hold.get()) _FF(__f, _Alloc(__a));
+            __f_ = __hold.release();
+        }
+    }
+}
+
+template<class _Rp, class _A0, class _A1>
+function<_Rp(_A0, _A1)>&
+function<_Rp(_A0, _A1)>::operator=(const function& __f)
+{
+    if (__f)
+        function(__f).swap(*this);
+    else
+        *this = nullptr;
+    return *this;
+}
+
+template<class _Rp, class _A0, class _A1>
+function<_Rp(_A0, _A1)>&
+function<_Rp(_A0, _A1)>::operator=(nullptr_t)
+{
+    __base* __t = __f_;
+    __f_ = 0;
+    if (__t == (__base*)&__buf_)
+        __t->destroy();
+    else if (__t)
+        __t->destroy_deallocate();
+    return *this;
+}
+
+template<class _Rp, class _A0, class _A1>
+template <class _Fp>
+typename enable_if
+<
+    !is_integral<_Fp>::value,
+    function<_Rp(_A0, _A1)>&
+>::type
+function<_Rp(_A0, _A1)>::operator=(_Fp __f)
+{
+    function(_VSTD::move(__f)).swap(*this);
+    return *this;
+}
+
+template<class _Rp, class _A0, class _A1>
+function<_Rp(_A0, _A1)>::~function()
+{
+    if (__f_ == (__base*)&__buf_)
+        __f_->destroy();
+    else if (__f_)
+        __f_->destroy_deallocate();
+}
+
+template<class _Rp, class _A0, class _A1>
+void
+function<_Rp(_A0, _A1)>::swap(function& __f)
+{
+    if (_VSTD::addressof(__f) == this)
+      return;
+    if (__f_ == (__base*)&__buf_ && __f.__f_ == (__base*)&__f.__buf_)
+    {
+        typename aligned_storage<sizeof(__buf_)>::type __tempbuf;
+        __base* __t = (__base*)&__tempbuf;
+        __f_->__clone(__t);
+        __f_->destroy();
+        __f_ = 0;
+        __f.__f_->__clone((__base*)&__buf_);
+        __f.__f_->destroy();
+        __f.__f_ = 0;
+        __f_ = (__base*)&__buf_;
+        __t->__clone((__base*)&__f.__buf_);
+        __t->destroy();
+        __f.__f_ = (__base*)&__f.__buf_;
+    }
+    else if (__f_ == (__base*)&__buf_)
+    {
+        __f_->__clone((__base*)&__f.__buf_);
+        __f_->destroy();
+        __f_ = __f.__f_;
+        __f.__f_ = (__base*)&__f.__buf_;
+    }
+    else if (__f.__f_ == (__base*)&__f.__buf_)
+    {
+        __f.__f_->__clone((__base*)&__buf_);
+        __f.__f_->destroy();
+        __f.__f_ = __f_;
+        __f_ = (__base*)&__buf_;
+    }
+    else
+        _VSTD::swap(__f_, __f.__f_);
+}
+
+template<class _Rp, class _A0, class _A1>
+_Rp
+function<_Rp(_A0, _A1)>::operator()(_A0 __a0, _A1 __a1) const
+{
+    if (__f_ == 0)
+        __throw_bad_function_call();
+    return (*__f_)(__a0, __a1);
+}
+
+#ifndef _LIBCPP_NO_RTTI
+
+template<class _Rp, class _A0, class _A1>
+const std::type_info&
+function<_Rp(_A0, _A1)>::target_type() const
+{
+    if (__f_ == 0)
+        return typeid(void);
+    return __f_->target_type();
+}
+
+template<class _Rp, class _A0, class _A1>
+template <typename _Tp>
+_Tp*
+function<_Rp(_A0, _A1)>::target()
+{
+    if (__f_ == 0)
+        return (_Tp*)0;
+    return (_Tp*) const_cast<void *>(__f_->target(typeid(_Tp)));
+}
+
+template<class _Rp, class _A0, class _A1>
+template <typename _Tp>
+const _Tp*
+function<_Rp(_A0, _A1)>::target() const
+{
+    if (__f_ == 0)
+        return (const _Tp*)0;
+    return (const _Tp*)__f_->target(typeid(_Tp));
+}
+
+#endif // _LIBCPP_NO_RTTI
+
+template<class _Rp, class _A0, class _A1, class _A2>
+class _LIBCPP_TEMPLATE_VIS function<_Rp(_A0, _A1, _A2)>
+{
+    typedef __function::__base<_Rp(_A0, _A1, _A2)> __base;
+    aligned_storage<3*sizeof(void*)>::type __buf_;
+    __base* __f_;
+
+public:
+    typedef _Rp result_type;
+
+    // 20.7.16.2.1, construct/copy/destroy:
+    _LIBCPP_INLINE_VISIBILITY explicit function() : __f_(0) {}
+    _LIBCPP_INLINE_VISIBILITY function(nullptr_t) : __f_(0) {}
+    function(const function&);
+    template<class _Fp>
+      function(_Fp,
+               typename enable_if<!is_integral<_Fp>::value>::type* = 0);
+
+    template<class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      function(allocator_arg_t, const _Alloc&) : __f_(0) {}
+    template<class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      function(allocator_arg_t, const _Alloc&, nullptr_t) : __f_(0) {}
+    template<class _Alloc>
+      function(allocator_arg_t, const _Alloc&, const function&);
+    template<class _Fp, class _Alloc>
+      function(allocator_arg_t, const _Alloc& __a, _Fp __f,
+               typename enable_if<!is_integral<_Fp>::value>::type* = 0);
+
+    function& operator=(const function&);
+    function& operator=(nullptr_t);
+    template<class _Fp>
+      typename enable_if
+      <
+        !is_integral<_Fp>::value,
+        function&
+      >::type
+      operator=(_Fp);
+
+    ~function();
+
+    // 20.7.16.2.2, function modifiers:
+    void swap(function&);
+    template<class _Fp, class _Alloc>
+      _LIBCPP_INLINE_VISIBILITY
+      void assign(_Fp __f, const _Alloc& __a)
+        {function(allocator_arg, __a, __f).swap(*this);}
+
+    // 20.7.16.2.3, function capacity:
+    _LIBCPP_INLINE_VISIBILITY explicit operator bool() const {return __f_;}
+
+private:
+    // deleted overloads close possible hole in the type system
+    template<class _R2, class _B0, class _B1, class _B2>
+      bool operator==(const function<_R2(_B0, _B1, _B2)>&) const;// = delete;
+    template<class _R2, class _B0, class _B1, class _B2>
+      bool operator!=(const function<_R2(_B0, _B1, _B2)>&) const;// = delete;
+public:
+    // 20.7.16.2.4, function invocation:
+    _Rp operator()(_A0, _A1, _A2) const;
+
+#ifndef _LIBCPP_NO_RTTI
+    // 20.7.16.2.5, function target access:
+    const std::type_info& target_type() const;
+    template <typename _Tp> _Tp* target();
+    template <typename _Tp> const _Tp* target() const;
+#endif // _LIBCPP_NO_RTTI
+};
+
+template<class _Rp, class _A0, class _A1, class _A2>
+function<_Rp(_A0, _A1, _A2)>::function(const function& __f)
+{
+    if (__f.__f_ == 0)
+        __f_ = 0;
+    else if (__f.__f_ == (const __base*)&__f.__buf_)
+    {
+        __f_ = (__base*)&__buf_;
+        __f.__f_->__clone(__f_);
+    }
+    else
+        __f_ = __f.__f_->__clone();
+}
+
+template<class _Rp, class _A0, class _A1, class _A2>
+template<class _Alloc>
+function<_Rp(_A0, _A1, _A2)>::function(allocator_arg_t, const _Alloc&,
+                                      const function& __f)
+{
+    if (__f.__f_ == 0)
+        __f_ = 0;
+    else if (__f.__f_ == (const __base*)&__f.__buf_)
+    {
+        __f_ = (__base*)&__buf_;
+        __f.__f_->__clone(__f_);
+    }
+    else
+        __f_ = __f.__f_->__clone();
+}
+
+template<class _Rp, class _A0, class _A1, class _A2>
+template <class _Fp>
+function<_Rp(_A0, _A1, _A2)>::function(_Fp __f,
+                                     typename enable_if<!is_integral<_Fp>::value>::type*)
+    : __f_(0)
+{
+    if (__function::__not_null(__f))
+    {
+        typedef __function::__func<_Fp, allocator<_Fp>, _Rp(_A0, _A1, _A2)> _FF;
+        if (sizeof(_FF) <= sizeof(__buf_))
+        {
+            __f_ = (__base*)&__buf_;
+            ::new ((void*)__f_) _FF(__f);
+        }
+        else
+        {
+            typedef allocator<_FF> _Ap;
+            _Ap __a;
+            typedef __allocator_destructor<_Ap> _Dp;
+            unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+            ::new ((void*)__hold.get()) _FF(__f, allocator<_Fp>(__a));
+            __f_ = __hold.release();
+        }
+    }
+}
+
+template<class _Rp, class _A0, class _A1, class _A2>
+template <class _Fp, class _Alloc>
+function<_Rp(_A0, _A1, _A2)>::function(allocator_arg_t, const _Alloc& __a0, _Fp __f,
+                                     typename enable_if<!is_integral<_Fp>::value>::type*)
+    : __f_(0)
+{
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    if (__function::__not_null(__f))
+    {
+        typedef __function::__func<_Fp, _Alloc, _Rp(_A0, _A1, _A2)> _FF;
+        if (sizeof(_FF) <= sizeof(__buf_))
+        {
+            __f_ = (__base*)&__buf_;
+            ::new ((void*)__f_) _FF(__f, __a0);
+        }
+        else
+        {
+            typedef typename __rebind_alloc_helper<__alloc_traits, _FF>::type _Ap;
+            _Ap __a(__a0);
+            typedef __allocator_destructor<_Ap> _Dp;
+            unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+            ::new ((void*)__hold.get()) _FF(__f, _Alloc(__a));
+            __f_ = __hold.release();
+        }
+    }
+}
+
+template<class _Rp, class _A0, class _A1, class _A2>
+function<_Rp(_A0, _A1, _A2)>&
+function<_Rp(_A0, _A1, _A2)>::operator=(const function& __f)
+{
+    if (__f)
+        function(__f).swap(*this);
+    else
+        *this = nullptr;
+    return *this;
+}
+
+template<class _Rp, class _A0, class _A1, class _A2>
+function<_Rp(_A0, _A1, _A2)>&
+function<_Rp(_A0, _A1, _A2)>::operator=(nullptr_t)
+{
+    __base* __t = __f_;
+    __f_ = 0;
+    if (__t == (__base*)&__buf_)
+        __t->destroy();
+    else if (__t)
+        __t->destroy_deallocate();
+    return *this;
+}
+
+template<class _Rp, class _A0, class _A1, class _A2>
+template <class _Fp>
+typename enable_if
+<
+    !is_integral<_Fp>::value,
+    function<_Rp(_A0, _A1, _A2)>&
+>::type
+function<_Rp(_A0, _A1, _A2)>::operator=(_Fp __f)
+{
+    function(_VSTD::move(__f)).swap(*this);
+    return *this;
+}
+
+template<class _Rp, class _A0, class _A1, class _A2>
+function<_Rp(_A0, _A1, _A2)>::~function()
+{
+    if (__f_ == (__base*)&__buf_)
+        __f_->destroy();
+    else if (__f_)
+        __f_->destroy_deallocate();
+}
+
+template<class _Rp, class _A0, class _A1, class _A2>
+void
+function<_Rp(_A0, _A1, _A2)>::swap(function& __f)
+{
+    if (_VSTD::addressof(__f) == this)
+      return;
+    if (__f_ == (__base*)&__buf_ && __f.__f_ == (__base*)&__f.__buf_)
+    {
+        typename aligned_storage<sizeof(__buf_)>::type __tempbuf;
+        __base* __t = (__base*)&__tempbuf;
+        __f_->__clone(__t);
+        __f_->destroy();
+        __f_ = 0;
+        __f.__f_->__clone((__base*)&__buf_);
+        __f.__f_->destroy();
+        __f.__f_ = 0;
+        __f_ = (__base*)&__buf_;
+        __t->__clone((__base*)&__f.__buf_);
+        __t->destroy();
+        __f.__f_ = (__base*)&__f.__buf_;
+    }
+    else if (__f_ == (__base*)&__buf_)
+    {
+        __f_->__clone((__base*)&__f.__buf_);
+        __f_->destroy();
+        __f_ = __f.__f_;
+        __f.__f_ = (__base*)&__f.__buf_;
+    }
+    else if (__f.__f_ == (__base*)&__f.__buf_)
+    {
+        __f.__f_->__clone((__base*)&__buf_);
+        __f.__f_->destroy();
+        __f.__f_ = __f_;
+        __f_ = (__base*)&__buf_;
+    }
+    else
+        _VSTD::swap(__f_, __f.__f_);
+}
+
+template<class _Rp, class _A0, class _A1, class _A2>
+_Rp
+function<_Rp(_A0, _A1, _A2)>::operator()(_A0 __a0, _A1 __a1, _A2 __a2) const
+{
+    if (__f_ == 0)
+        __throw_bad_function_call();
+    return (*__f_)(__a0, __a1, __a2);
+}
+
+#ifndef _LIBCPP_NO_RTTI
+
+template<class _Rp, class _A0, class _A1, class _A2>
+const std::type_info&
+function<_Rp(_A0, _A1, _A2)>::target_type() const
+{
+    if (__f_ == 0)
+        return typeid(void);
+    return __f_->target_type();
+}
+
+template<class _Rp, class _A0, class _A1, class _A2>
+template <typename _Tp>
+_Tp*
+function<_Rp(_A0, _A1, _A2)>::target()
+{
+    if (__f_ == 0)
+        return (_Tp*)0;
+    return (_Tp*) const_cast<void *>(__f_->target(typeid(_Tp)));
+}
+
+template<class _Rp, class _A0, class _A1, class _A2>
+template <typename _Tp>
+const _Tp*
+function<_Rp(_A0, _A1, _A2)>::target() const
+{
+    if (__f_ == 0)
+        return (const _Tp*)0;
+    return (const _Tp*)__f_->target(typeid(_Tp));
+}
+
+#endif // _LIBCPP_NO_RTTI
+
+template <class _Fp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const function<_Fp>& __f, nullptr_t) {return !__f;}
+
+template <class _Fp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(nullptr_t, const function<_Fp>& __f) {return !__f;}
+
+template <class _Fp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const function<_Fp>& __f, nullptr_t) {return (bool)__f;}
+
+template <class _Fp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(nullptr_t, const function<_Fp>& __f) {return (bool)__f;}
+
+template <class _Fp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(function<_Fp>& __x, function<_Fp>& __y)
+{return __x.swap(__y);}
+
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_FUNCTION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/hash.h b/contrib/libs/cxxsupp/libcxx/include/__functional/hash.h
new file mode 100644
index 00000000000..728f487161b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/hash.h
@@ -0,0 +1,878 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_HASH_H
+#define _LIBCPP___FUNCTIONAL_HASH_H
+
+#include <__config>
+#include <__functional/unary_function.h>
+#include <__tuple>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+#include <__utility/swap.h>
+#include <cstdint>
+#include <cstring>
+#include <cstddef>
+#include <limits>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+_Size
+__loadword(const void* __p)
+{
+    _Size __r;
+    _VSTD::memcpy(&__r, __p, sizeof(__r));
+    return __r;
+}
+
+// We use murmur2 when size_t is 32 bits, and cityhash64 when size_t
+// is 64 bits.  This is because cityhash64 uses 64bit x 64bit
+// multiplication, which can be very slow on 32-bit systems.
+template <class _Size, size_t = sizeof(_Size)*__CHAR_BIT__>
+struct __murmur2_or_cityhash;
+
+template <class _Size>
+struct __murmur2_or_cityhash<_Size, 32>
+{
+    inline _Size operator()(const void* __key, _Size __len)
+         _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
+};
+
+// murmur2
+template <class _Size>
+_Size
+__murmur2_or_cityhash<_Size, 32>::operator()(const void* __key, _Size __len)
+{
+    const _Size __m = 0x5bd1e995;
+    const _Size __r = 24;
+    _Size __h = __len;
+    const unsigned char* __data = static_cast<const unsigned char*>(__key);
+    for (; __len >= 4; __data += 4, __len -= 4)
+    {
+        _Size __k = __loadword<_Size>(__data);
+        __k *= __m;
+        __k ^= __k >> __r;
+        __k *= __m;
+        __h *= __m;
+        __h ^= __k;
+    }
+    switch (__len)
+    {
+    case 3:
+        __h ^= static_cast<_Size>(__data[2] << 16);
+        _LIBCPP_FALLTHROUGH();
+    case 2:
+        __h ^= static_cast<_Size>(__data[1] << 8);
+        _LIBCPP_FALLTHROUGH();
+    case 1:
+        __h ^= __data[0];
+        __h *= __m;
+    }
+    __h ^= __h >> 13;
+    __h *= __m;
+    __h ^= __h >> 15;
+    return __h;
+}
+
+template <class _Size>
+struct __murmur2_or_cityhash<_Size, 64>
+{
+    inline _Size operator()(const void* __key, _Size __len)  _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
+
+ private:
+  // Some primes between 2^63 and 2^64.
+  static const _Size __k0 = 0xc3a5c85c97cb3127ULL;
+  static const _Size __k1 = 0xb492b66fbe98f273ULL;
+  static const _Size __k2 = 0x9ae16a3b2f90404fULL;
+  static const _Size __k3 = 0xc949d7c7509e6557ULL;
+
+  static _Size __rotate(_Size __val, int __shift) {
+    return __shift == 0 ? __val : ((__val >> __shift) | (__val << (64 - __shift)));
+  }
+
+  static _Size __rotate_by_at_least_1(_Size __val, int __shift) {
+    return (__val >> __shift) | (__val << (64 - __shift));
+  }
+
+  static _Size __shift_mix(_Size __val) {
+    return __val ^ (__val >> 47);
+  }
+
+  static _Size __hash_len_16(_Size __u, _Size __v)
+     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+  {
+    const _Size __mul = 0x9ddfea08eb382d69ULL;
+    _Size __a = (__u ^ __v) * __mul;
+    __a ^= (__a >> 47);
+    _Size __b = (__v ^ __a) * __mul;
+    __b ^= (__b >> 47);
+    __b *= __mul;
+    return __b;
+  }
+
+  static _Size __hash_len_0_to_16(const char* __s, _Size __len)
+     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+  {
+    if (__len > 8) {
+      const _Size __a = __loadword<_Size>(__s);
+      const _Size __b = __loadword<_Size>(__s + __len - 8);
+      return __hash_len_16(__a, __rotate_by_at_least_1(__b + __len, __len)) ^ __b;
+    }
+    if (__len >= 4) {
+      const uint32_t __a = __loadword<uint32_t>(__s);
+      const uint32_t __b = __loadword<uint32_t>(__s + __len - 4);
+      return __hash_len_16(__len + (__a << 3), __b);
+    }
+    if (__len > 0) {
+      const unsigned char __a = static_cast<unsigned char>(__s[0]);
+      const unsigned char __b = static_cast<unsigned char>(__s[__len >> 1]);
+      const unsigned char __c = static_cast<unsigned char>(__s[__len - 1]);
+      const uint32_t __y = static_cast<uint32_t>(__a) +
+                           (static_cast<uint32_t>(__b) << 8);
+      const uint32_t __z = __len + (static_cast<uint32_t>(__c) << 2);
+      return __shift_mix(__y * __k2 ^ __z * __k3) * __k2;
+    }
+    return __k2;
+  }
+
+  static _Size __hash_len_17_to_32(const char *__s, _Size __len)
+     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+  {
+    const _Size __a = __loadword<_Size>(__s) * __k1;
+    const _Size __b = __loadword<_Size>(__s + 8);
+    const _Size __c = __loadword<_Size>(__s + __len - 8) * __k2;
+    const _Size __d = __loadword<_Size>(__s + __len - 16) * __k0;
+    return __hash_len_16(__rotate(__a - __b, 43) + __rotate(__c, 30) + __d,
+                         __a + __rotate(__b ^ __k3, 20) - __c + __len);
+  }
+
+  // Return a 16-byte hash for 48 bytes.  Quick and dirty.
+  // Callers do best to use "random-looking" values for a and b.
+  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
+      _Size __w, _Size __x, _Size __y, _Size __z, _Size __a, _Size __b)
+        _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+  {
+    __a += __w;
+    __b = __rotate(__b + __a + __z, 21);
+    const _Size __c = __a;
+    __a += __x;
+    __a += __y;
+    __b += __rotate(__a, 44);
+    return pair<_Size, _Size>(__a + __z, __b + __c);
+  }
+
+  // Return a 16-byte hash for s[0] ... s[31], a, and b.  Quick and dirty.
+  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
+      const char* __s, _Size __a, _Size __b)
+    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+  {
+    return __weak_hash_len_32_with_seeds(__loadword<_Size>(__s),
+                                         __loadword<_Size>(__s + 8),
+                                         __loadword<_Size>(__s + 16),
+                                         __loadword<_Size>(__s + 24),
+                                         __a,
+                                         __b);
+  }
+
+  // Return an 8-byte hash for 33 to 64 bytes.
+  static _Size __hash_len_33_to_64(const char *__s, size_t __len)
+    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+  {
+    _Size __z = __loadword<_Size>(__s + 24);
+    _Size __a = __loadword<_Size>(__s) +
+                (__len + __loadword<_Size>(__s + __len - 16)) * __k0;
+    _Size __b = __rotate(__a + __z, 52);
+    _Size __c = __rotate(__a, 37);
+    __a += __loadword<_Size>(__s + 8);
+    __c += __rotate(__a, 7);
+    __a += __loadword<_Size>(__s + 16);
+    _Size __vf = __a + __z;
+    _Size __vs = __b + __rotate(__a, 31) + __c;
+    __a = __loadword<_Size>(__s + 16) + __loadword<_Size>(__s + __len - 32);
+    __z += __loadword<_Size>(__s + __len - 8);
+    __b = __rotate(__a + __z, 52);
+    __c = __rotate(__a, 37);
+    __a += __loadword<_Size>(__s + __len - 24);
+    __c += __rotate(__a, 7);
+    __a += __loadword<_Size>(__s + __len - 16);
+    _Size __wf = __a + __z;
+    _Size __ws = __b + __rotate(__a, 31) + __c;
+    _Size __r = __shift_mix((__vf + __ws) * __k2 + (__wf + __vs) * __k0);
+    return __shift_mix(__r * __k0 + __vs) * __k2;
+  }
+};
+
+// cityhash64
+template <class _Size>
+_Size
+__murmur2_or_cityhash<_Size, 64>::operator()(const void* __key, _Size __len)
+{
+  const char* __s = static_cast<const char*>(__key);
+  if (__len <= 32) {
+    if (__len <= 16) {
+      return __hash_len_0_to_16(__s, __len);
+    } else {
+      return __hash_len_17_to_32(__s, __len);
+    }
+  } else if (__len <= 64) {
+    return __hash_len_33_to_64(__s, __len);
+  }
+
+  // For strings over 64 bytes we hash the end first, and then as we
+  // loop we keep 56 bytes of state: v, w, x, y, and z.
+  _Size __x = __loadword<_Size>(__s + __len - 40);
+  _Size __y = __loadword<_Size>(__s + __len - 16) +
+              __loadword<_Size>(__s + __len - 56);
+  _Size __z = __hash_len_16(__loadword<_Size>(__s + __len - 48) + __len,
+                          __loadword<_Size>(__s + __len - 24));
+  pair<_Size, _Size> __v = __weak_hash_len_32_with_seeds(__s + __len - 64, __len, __z);
+  pair<_Size, _Size> __w = __weak_hash_len_32_with_seeds(__s + __len - 32, __y + __k1, __x);
+  __x = __x * __k1 + __loadword<_Size>(__s);
+
+  // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
+  __len = (__len - 1) & ~static_cast<_Size>(63);
+  do {
+    __x = __rotate(__x + __y + __v.first + __loadword<_Size>(__s + 8), 37) * __k1;
+    __y = __rotate(__y + __v.second + __loadword<_Size>(__s + 48), 42) * __k1;
+    __x ^= __w.second;
+    __y += __v.first + __loadword<_Size>(__s + 40);
+    __z = __rotate(__z + __w.first, 33) * __k1;
+    __v = __weak_hash_len_32_with_seeds(__s, __v.second * __k1, __x + __w.first);
+    __w = __weak_hash_len_32_with_seeds(__s + 32, __z + __w.second,
+                                        __y + __loadword<_Size>(__s + 16));
+    _VSTD::swap(__z, __x);
+    __s += 64;
+    __len -= 64;
+  } while (__len != 0);
+  return __hash_len_16(
+      __hash_len_16(__v.first, __w.first) + __shift_mix(__y) * __k1 + __z,
+      __hash_len_16(__v.second, __w.second) + __x);
+}
+
+template <class _Tp, size_t = sizeof(_Tp) / sizeof(size_t)>
+struct __scalar_hash;
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp>
+struct __scalar_hash<_Tp, 0>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp __v) const _NOEXCEPT
+    {
+        union
+        {
+            _Tp    __t;
+            size_t __a;
+        } __u;
+        __u.__a = 0;
+        __u.__t = __v;
+        return __u.__a;
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp>
+struct __scalar_hash<_Tp, 1>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp __v) const _NOEXCEPT
+    {
+        union
+        {
+            _Tp    __t;
+            size_t __a;
+        } __u;
+        __u.__t = __v;
+        return __u.__a;
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp>
+struct __scalar_hash<_Tp, 2>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp __v) const _NOEXCEPT
+    {
+        union
+        {
+            _Tp __t;
+            struct
+            {
+                size_t __a;
+                size_t __b;
+            } __s;
+        } __u;
+        __u.__t = __v;
+        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp>
+struct __scalar_hash<_Tp, 3>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp __v) const _NOEXCEPT
+    {
+        union
+        {
+            _Tp __t;
+            struct
+            {
+                size_t __a;
+                size_t __b;
+                size_t __c;
+            } __s;
+        } __u;
+        __u.__t = __v;
+        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp>
+struct __scalar_hash<_Tp, 4>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp __v) const _NOEXCEPT
+    {
+        union
+        {
+            _Tp __t;
+            struct
+            {
+                size_t __a;
+                size_t __b;
+                size_t __c;
+                size_t __d;
+            } __s;
+        } __u;
+        __u.__t = __v;
+        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
+    }
+};
+
+struct _PairT {
+  size_t first;
+  size_t second;
+};
+
+// Disable double inline warning.
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4141 )
+#endif
+_LIBCPP_INLINE_VISIBILITY
+inline size_t __hash_combine(size_t __lhs, size_t __rhs) _NOEXCEPT {
+    typedef __scalar_hash<_PairT> _HashT;
+    const _PairT __p = {__lhs, __rhs};
+    return _HashT()(__p);
+}
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS hash<_Tp*>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp*, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp* argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp* __v) const _NOEXCEPT
+    {
+        union
+        {
+            _Tp* __t;
+            size_t __a;
+        } __u;
+        __u.__t = __v;
+        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<bool>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<bool, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(bool __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<char>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<char, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef char argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<signed char>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<signed char, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef signed char argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(signed char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<unsigned char>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<unsigned char, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned char argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(unsigned char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<char8_t>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<char8_t, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef char8_t argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(char8_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+#endif // !_LIBCPP_HAS_NO_CHAR8_T
+
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<char16_t>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<char16_t, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef char16_t argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(char16_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<char32_t>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<char32_t, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef char32_t argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(char32_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+#endif // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<wchar_t>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<wchar_t, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef wchar_t argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(wchar_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<short>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<short, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef short argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<unsigned short>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<unsigned short, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned short argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(unsigned short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<int>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<int, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef int argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<unsigned int>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<unsigned int, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned int argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(unsigned int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<long>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<long, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef long argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<unsigned long>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<unsigned long, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef unsigned long argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(unsigned long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
+};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<long long>
+    : public __scalar_hash<long long>
+{
+};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<unsigned long long>
+    : public __scalar_hash<unsigned long long>
+{
+};
+
+#ifndef _LIBCPP_HAS_NO_INT128
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<__int128_t>
+    : public __scalar_hash<__int128_t>
+{
+};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<__uint128_t>
+    : public __scalar_hash<__uint128_t>
+{
+};
+
+#endif
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<float>
+    : public __scalar_hash<float>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(float __v) const _NOEXCEPT
+    {
+        // -0.0 and 0.0 should return same hash
+       if (__v == 0.0f)
+           return 0;
+        return __scalar_hash<float>::operator()(__v);
+    }
+};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<double>
+    : public __scalar_hash<double>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(double __v) const _NOEXCEPT
+    {
+        // -0.0 and 0.0 should return same hash
+       if (__v == 0.0)
+           return 0;
+        return __scalar_hash<double>::operator()(__v);
+    }
+};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<long double>
+    : public __scalar_hash<long double>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(long double __v) const _NOEXCEPT
+    {
+        // -0.0 and 0.0 should return same hash
+        if (__v == 0.0L)
+            return 0;
+#if defined(__i386__) || (defined(__x86_64__) && defined(__ILP32__))
+        // Zero out padding bits
+        union
+        {
+            long double __t;
+            struct
+            {
+                size_t __a;
+                size_t __b;
+                size_t __c;
+                size_t __d;
+            } __s;
+        } __u;
+        __u.__s.__a = 0;
+        __u.__s.__b = 0;
+        __u.__s.__c = 0;
+        __u.__s.__d = 0;
+        __u.__t = __v;
+        return __u.__s.__a ^ __u.__s.__b ^ __u.__s.__c ^ __u.__s.__d;
+#elif defined(__x86_64__)
+        // Zero out padding bits
+        union
+        {
+            long double __t;
+            struct
+            {
+                size_t __a;
+                size_t __b;
+            } __s;
+        } __u;
+        __u.__s.__a = 0;
+        __u.__s.__b = 0;
+        __u.__t = __v;
+        return __u.__s.__a ^ __u.__s.__b;
+#else
+        return __scalar_hash<long double>::operator()(__v);
+#endif
+    }
+};
+
+#if _LIBCPP_STD_VER > 11
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp, bool = is_enum<_Tp>::value>
+struct _LIBCPP_TEMPLATE_VIS __enum_hash
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public unary_function<_Tp, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(_Tp __v) const _NOEXCEPT
+    {
+        typedef typename underlying_type<_Tp>::type type;
+        return hash<type>{}(static_cast<type>(__v));
+    }
+};
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS __enum_hash<_Tp, false> {
+    __enum_hash() = delete;
+    __enum_hash(__enum_hash const&) = delete;
+    __enum_hash& operator=(__enum_hash const&) = delete;
+};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS hash : public __enum_hash<_Tp>
+{
+};
+#endif
+
+#if _LIBCPP_STD_VER > 14
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<nullptr_t>
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+  : public unary_function<nullptr_t, size_t>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef nullptr_t argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(nullptr_t) const _NOEXCEPT {
+        return 662607004ull;
+    }
+};
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Key, class _Hash>
+using __check_hash_requirements _LIBCPP_NODEBUG = integral_constant<bool,
+    is_copy_constructible<_Hash>::value &&
+    is_move_constructible<_Hash>::value &&
+    __invokable_r<size_t, _Hash, _Key const&>::value
+>;
+
+template <class _Key, class _Hash = hash<_Key> >
+using __has_enabled_hash _LIBCPP_NODEBUG = integral_constant<bool,
+    __check_hash_requirements<_Key, _Hash>::value &&
+    is_default_constructible<_Hash>::value
+>;
+
+#if _LIBCPP_STD_VER > 14
+template <class _Type, class>
+using __enable_hash_helper_imp _LIBCPP_NODEBUG = _Type;
+
+template <class _Type, class ..._Keys>
+using __enable_hash_helper _LIBCPP_NODEBUG = __enable_hash_helper_imp<_Type,
+  typename enable_if<__all<__has_enabled_hash<_Keys>::value...>::value>::type
+>;
+#else
+template <class _Type, class ...>
+using __enable_hash_helper _LIBCPP_NODEBUG = _Type;
+#endif
+
+#endif // !_LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_HASH_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/identity.h b/contrib/libs/cxxsupp/libcxx/include/__functional/identity.h
new file mode 100644
index 00000000000..6b8346b3b2a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/identity.h
@@ -0,0 +1,37 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_IDENTITY_H
+#define _LIBCPP___FUNCTIONAL_IDENTITY_H
+
+#include <__config>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+struct identity {
+    template<class _Tp>
+    _LIBCPP_NODISCARD_EXT constexpr _Tp&& operator()(_Tp&& __t) const noexcept
+    {
+        return _VSTD::forward<_Tp>(__t);
+    }
+
+    using is_transparent = void;
+};
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_IDENTITY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/invoke.h b/contrib/libs/cxxsupp/libcxx/include/__functional/invoke.h
new file mode 100644
index 00000000000..0e167c75d69
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/invoke.h
@@ -0,0 +1,100 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_INVOKE_H
+#define _LIBCPP___FUNCTIONAL_INVOKE_H
+
+#include <__config>
+#include <__functional/weak_result_type.h>
+#include <__utility/forward.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Ret, bool = is_void<_Ret>::value>
+struct __invoke_void_return_wrapper
+{
+#ifndef _LIBCPP_CXX03_LANG
+    template <class ..._Args>
+    static _Ret __call(_Args&&... __args) {
+        return _VSTD::__invoke(_VSTD::forward<_Args>(__args)...);
+    }
+#else
+    template <class _Fn>
+    static _Ret __call(_Fn __f) {
+        return _VSTD::__invoke(__f);
+    }
+
+    template <class _Fn, class _A0>
+    static _Ret __call(_Fn __f, _A0& __a0) {
+        return _VSTD::__invoke(__f, __a0);
+    }
+
+    template <class _Fn, class _A0, class _A1>
+    static _Ret __call(_Fn __f, _A0& __a0, _A1& __a1) {
+        return _VSTD::__invoke(__f, __a0, __a1);
+    }
+
+    template <class _Fn, class _A0, class _A1, class _A2>
+    static _Ret __call(_Fn __f, _A0& __a0, _A1& __a1, _A2& __a2){
+        return _VSTD::__invoke(__f, __a0, __a1, __a2);
+    }
+#endif
+};
+
+template <class _Ret>
+struct __invoke_void_return_wrapper<_Ret, true>
+{
+#ifndef _LIBCPP_CXX03_LANG
+    template <class ..._Args>
+    static void __call(_Args&&... __args) {
+        _VSTD::__invoke(_VSTD::forward<_Args>(__args)...);
+    }
+#else
+    template <class _Fn>
+    static void __call(_Fn __f) {
+        _VSTD::__invoke(__f);
+    }
+
+    template <class _Fn, class _A0>
+    static void __call(_Fn __f, _A0& __a0) {
+        _VSTD::__invoke(__f, __a0);
+    }
+
+    template <class _Fn, class _A0, class _A1>
+    static void __call(_Fn __f, _A0& __a0, _A1& __a1) {
+        _VSTD::__invoke(__f, __a0, __a1);
+    }
+
+    template <class _Fn, class _A0, class _A1, class _A2>
+    static void __call(_Fn __f, _A0& __a0, _A1& __a1, _A2& __a2) {
+        _VSTD::__invoke(__f, __a0, __a1, __a2);
+    }
+#endif
+};
+
+#if _LIBCPP_STD_VER > 14
+
+template <class _Fn, class ..._Args>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 invoke_result_t<_Fn, _Args...>
+invoke(_Fn&& __f, _Args&&... __args)
+    noexcept(is_nothrow_invocable_v<_Fn, _Args...>)
+{
+    return _VSTD::__invoke(_VSTD::forward<_Fn>(__f), _VSTD::forward<_Args>(__args)...);
+}
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_INVOKE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/is_transparent.h b/contrib/libs/cxxsupp/libcxx/include/__functional/is_transparent.h
new file mode 100644
index 00000000000..4a72aa8e29e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/is_transparent.h
@@ -0,0 +1,36 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_IS_TRANSPARENT
+#define _LIBCPP___FUNCTIONAL_IS_TRANSPARENT
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 11
+
+template <class _Tp, class, class = void>
+struct __is_transparent : false_type {};
+
+template <class _Tp, class _Up>
+struct __is_transparent<_Tp, _Up,
+                        typename __void_t<typename _Tp::is_transparent>::type>
+   : true_type {};
+
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_IS_TRANSPARENT
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/mem_fn.h b/contrib/libs/cxxsupp/libcxx/include/__functional/mem_fn.h
new file mode 100644
index 00000000000..1fa070a42cc
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/mem_fn.h
@@ -0,0 +1,161 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_MEM_FN_H
+#define _LIBCPP___FUNCTIONAL_MEM_FN_H
+
+#include <__config>
+#include <__functional/weak_result_type.h>
+#include <__functional/binary_function.h>
+#include <__functional/invoke.h>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+class __mem_fn
+#if _LIBCPP_STD_VER <= 17 || !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public __weak_result_type<_Tp>
+#endif
+{
+public:
+    // types
+    typedef _Tp type;
+private:
+    type __f_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    __mem_fn(type __f) _NOEXCEPT : __f_(__f) {}
+
+#ifndef _LIBCPP_CXX03_LANG
+    // invoke
+    template <class... _ArgTypes>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    typename __invoke_return<type, _ArgTypes...>::type
+    operator() (_ArgTypes&&... __args) const {
+        return _VSTD::__invoke(__f_, _VSTD::forward<_ArgTypes>(__args)...);
+    }
+#else
+
+    template <class _A0>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return0<type, _A0>::type
+    operator() (_A0& __a0) const {
+        return _VSTD::__invoke(__f_, __a0);
+    }
+
+    template <class _A0>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return0<type, _A0 const>::type
+    operator() (_A0 const& __a0) const {
+        return _VSTD::__invoke(__f_, __a0);
+    }
+
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0, _A1>::type
+    operator() (_A0& __a0, _A1& __a1) const {
+        return _VSTD::__invoke(__f_, __a0, __a1);
+    }
+
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0 const, _A1>::type
+    operator() (_A0 const& __a0, _A1& __a1) const {
+        return _VSTD::__invoke(__f_, __a0, __a1);
+    }
+
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0, _A1 const>::type
+    operator() (_A0& __a0, _A1 const& __a1) const {
+        return _VSTD::__invoke(__f_, __a0, __a1);
+    }
+
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0 const, _A1 const>::type
+    operator() (_A0 const& __a0, _A1 const& __a1) const {
+        return _VSTD::__invoke(__f_, __a0, __a1);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1, _A2>::type
+    operator() (_A0& __a0, _A1& __a1, _A2& __a2) const {
+        return _VSTD::__invoke(__f_, __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1, _A2>::type
+    operator() (_A0 const& __a0, _A1& __a1, _A2& __a2) const {
+        return _VSTD::__invoke(__f_, __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1 const, _A2>::type
+    operator() (_A0& __a0, _A1 const& __a1, _A2& __a2) const {
+        return _VSTD::__invoke(__f_, __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1, _A2 const>::type
+    operator() (_A0& __a0, _A1& __a1, _A2 const& __a2) const {
+        return _VSTD::__invoke(__f_, __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1 const, _A2>::type
+    operator() (_A0 const& __a0, _A1 const& __a1, _A2& __a2) const {
+        return _VSTD::__invoke(__f_, __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1, _A2 const>::type
+    operator() (_A0 const& __a0, _A1& __a1, _A2 const& __a2) const {
+        return _VSTD::__invoke(__f_, __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1 const, _A2 const>::type
+    operator() (_A0& __a0, _A1 const& __a1, _A2 const& __a2) const {
+        return _VSTD::__invoke(__f_, __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1 const, _A2 const>::type
+    operator() (_A0 const& __a0, _A1 const& __a1, _A2 const& __a2) const {
+        return _VSTD::__invoke(__f_, __a0, __a1, __a2);
+    }
+#endif
+};
+
+template<class _Rp, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+__mem_fn<_Rp _Tp::*>
+mem_fn(_Rp _Tp::* __pm) _NOEXCEPT
+{
+    return __mem_fn<_Rp _Tp::*>(__pm);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_MEM_FN_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/mem_fun_ref.h b/contrib/libs/cxxsupp/libcxx/include/__functional/mem_fun_ref.h
new file mode 100644
index 00000000000..4616da0b074
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/mem_fun_ref.h
@@ -0,0 +1,173 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_MEM_FUN_REF_H
+#define _LIBCPP___FUNCTIONAL_MEM_FUN_REF_H
+
+#include <__config>
+#include <__functional/unary_function.h>
+#include <__functional/binary_function.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_BINDERS)
+
+template<class _Sp, class _Tp>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 mem_fun_t
+    : public unary_function<_Tp*, _Sp>
+{
+    _Sp (_Tp::*__p_)();
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit mem_fun_t(_Sp (_Tp::*__p)())
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY _Sp operator()(_Tp* __p) const
+        {return (__p->*__p_)();}
+};
+
+template<class _Sp, class _Tp, class _Ap>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 mem_fun1_t
+    : public binary_function<_Tp*, _Ap, _Sp>
+{
+    _Sp (_Tp::*__p_)(_Ap);
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit mem_fun1_t(_Sp (_Tp::*__p)(_Ap))
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY _Sp operator()(_Tp* __p, _Ap __x) const
+        {return (__p->*__p_)(__x);}
+};
+
+template<class _Sp, class _Tp>
+_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
+mem_fun_t<_Sp,_Tp>
+mem_fun(_Sp (_Tp::*__f)())
+    {return mem_fun_t<_Sp,_Tp>(__f);}
+
+template<class _Sp, class _Tp, class _Ap>
+_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
+mem_fun1_t<_Sp,_Tp,_Ap>
+mem_fun(_Sp (_Tp::*__f)(_Ap))
+    {return mem_fun1_t<_Sp,_Tp,_Ap>(__f);}
+
+template<class _Sp, class _Tp>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 mem_fun_ref_t
+    : public unary_function<_Tp, _Sp>
+{
+    _Sp (_Tp::*__p_)();
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit mem_fun_ref_t(_Sp (_Tp::*__p)())
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY _Sp operator()(_Tp& __p) const
+        {return (__p.*__p_)();}
+};
+
+template<class _Sp, class _Tp, class _Ap>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 mem_fun1_ref_t
+    : public binary_function<_Tp, _Ap, _Sp>
+{
+    _Sp (_Tp::*__p_)(_Ap);
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit mem_fun1_ref_t(_Sp (_Tp::*__p)(_Ap))
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY _Sp operator()(_Tp& __p, _Ap __x) const
+        {return (__p.*__p_)(__x);}
+};
+
+template<class _Sp, class _Tp>
+_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
+mem_fun_ref_t<_Sp,_Tp>
+mem_fun_ref(_Sp (_Tp::*__f)())
+    {return mem_fun_ref_t<_Sp,_Tp>(__f);}
+
+template<class _Sp, class _Tp, class _Ap>
+_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
+mem_fun1_ref_t<_Sp,_Tp,_Ap>
+mem_fun_ref(_Sp (_Tp::*__f)(_Ap))
+    {return mem_fun1_ref_t<_Sp,_Tp,_Ap>(__f);}
+
+template <class _Sp, class _Tp>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 const_mem_fun_t
+    : public unary_function<const _Tp*, _Sp>
+{
+    _Sp (_Tp::*__p_)() const;
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit const_mem_fun_t(_Sp (_Tp::*__p)() const)
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY _Sp operator()(const _Tp* __p) const
+        {return (__p->*__p_)();}
+};
+
+template <class _Sp, class _Tp, class _Ap>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 const_mem_fun1_t
+    : public binary_function<const _Tp*, _Ap, _Sp>
+{
+    _Sp (_Tp::*__p_)(_Ap) const;
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit const_mem_fun1_t(_Sp (_Tp::*__p)(_Ap) const)
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY _Sp operator()(const _Tp* __p, _Ap __x) const
+        {return (__p->*__p_)(__x);}
+};
+
+template <class _Sp, class _Tp>
+_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
+const_mem_fun_t<_Sp,_Tp>
+mem_fun(_Sp (_Tp::*__f)() const)
+    {return const_mem_fun_t<_Sp,_Tp>(__f);}
+
+template <class _Sp, class _Tp, class _Ap>
+_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
+const_mem_fun1_t<_Sp,_Tp,_Ap>
+mem_fun(_Sp (_Tp::*__f)(_Ap) const)
+    {return const_mem_fun1_t<_Sp,_Tp,_Ap>(__f);}
+
+template <class _Sp, class _Tp>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 const_mem_fun_ref_t
+    : public unary_function<_Tp, _Sp>
+{
+    _Sp (_Tp::*__p_)() const;
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit const_mem_fun_ref_t(_Sp (_Tp::*__p)() const)
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY _Sp operator()(const _Tp& __p) const
+        {return (__p.*__p_)();}
+};
+
+template <class _Sp, class _Tp, class _Ap>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 const_mem_fun1_ref_t
+    : public binary_function<_Tp, _Ap, _Sp>
+{
+    _Sp (_Tp::*__p_)(_Ap) const;
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit const_mem_fun1_ref_t(_Sp (_Tp::*__p)(_Ap) const)
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY _Sp operator()(const _Tp& __p, _Ap __x) const
+        {return (__p.*__p_)(__x);}
+};
+
+template <class _Sp, class _Tp>
+_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
+const_mem_fun_ref_t<_Sp,_Tp>
+mem_fun_ref(_Sp (_Tp::*__f)() const)
+    {return const_mem_fun_ref_t<_Sp,_Tp>(__f);}
+
+template <class _Sp, class _Tp, class _Ap>
+_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
+const_mem_fun1_ref_t<_Sp,_Tp,_Ap>
+mem_fun_ref(_Sp (_Tp::*__f)(_Ap) const)
+    {return const_mem_fun1_ref_t<_Sp,_Tp,_Ap>(__f);}
+
+#endif // _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_BINDERS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_MEM_FUN_REF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/not_fn.h b/contrib/libs/cxxsupp/libcxx/include/__functional/not_fn.h
new file mode 100644
index 00000000000..5e250c12537
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/not_fn.h
@@ -0,0 +1,53 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_NOT_FN_H
+#define _LIBCPP___FUNCTIONAL_NOT_FN_H
+
+#include <__config>
+#include <__functional/perfect_forward.h>
+#include <__functional/invoke.h>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+struct __not_fn_op {
+    template<class... _Args>
+    _LIBCPP_HIDE_FROM_ABI
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 auto operator()(_Args&&... __args) const
+        noexcept(noexcept(!_VSTD::invoke(_VSTD::forward<_Args>(__args)...)))
+        -> decltype(      !_VSTD::invoke(_VSTD::forward<_Args>(__args)...))
+        { return          !_VSTD::invoke(_VSTD::forward<_Args>(__args)...); }
+};
+
+template <class _Fn>
+struct __not_fn_t : __perfect_forward<__not_fn_op, _Fn> {
+    using __perfect_forward<__not_fn_op, _Fn>::__perfect_forward;
+};
+
+template<class _Fn, class = enable_if_t<
+    is_constructible_v<decay_t<_Fn>, _Fn> &&
+    is_move_constructible_v<decay_t<_Fn>>
+>>
+_LIBCPP_HIDE_FROM_ABI
+_LIBCPP_CONSTEXPR_AFTER_CXX17 auto not_fn(_Fn&& __f) {
+    return __not_fn_t<decay_t<_Fn>>(tuple<>(), _VSTD::forward<_Fn>(__f));
+}
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_NOT_FN_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/operations.h b/contrib/libs/cxxsupp/libcxx/include/__functional/operations.h
new file mode 100644
index 00000000000..0c7c6d4fcfa
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/operations.h
@@ -0,0 +1,729 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_OPERATIONS_H
+#define _LIBCPP___FUNCTIONAL_OPERATIONS_H
+
+#include <__config>
+#include <__functional/binary_function.h>
+#include <__functional/unary_function.h>
+#include <__utility/forward.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Arithmetic operations
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS plus
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, _Tp>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef _Tp __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x + __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS plus<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) + _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) + _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) + _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS minus
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, _Tp>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef _Tp __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x - __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS minus<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) - _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) - _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) - _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS multiplies
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, _Tp>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef _Tp __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x * __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS multiplies<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) * _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) * _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) * _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS divides
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, _Tp>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef _Tp __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x / __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS divides<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) / _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) / _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) / _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS modulus
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, _Tp>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef _Tp __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x % __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS modulus<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) % _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) % _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) % _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS negate
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : unary_function<_Tp, _Tp>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef _Tp __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return -__x;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS negate<void>
+{
+    template <class _Tp>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_Tp&& __x) const
+        noexcept(noexcept(- _VSTD::forward<_Tp>(__x)))
+        -> decltype(      - _VSTD::forward<_Tp>(__x))
+        { return          - _VSTD::forward<_Tp>(__x); }
+    typedef void is_transparent;
+};
+#endif
+
+// Bitwise operations
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS bit_and
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, _Tp>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef _Tp __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x & __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS bit_and<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) & _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) & _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) & _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+#if _LIBCPP_STD_VER > 11
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp = void>
+struct _LIBCPP_TEMPLATE_VIS bit_not
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : unary_function<_Tp, _Tp>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return ~__x;}
+};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS bit_not<void>
+{
+    template <class _Tp>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_Tp&& __x) const
+        noexcept(noexcept(~_VSTD::forward<_Tp>(__x)))
+        -> decltype(      ~_VSTD::forward<_Tp>(__x))
+        { return          ~_VSTD::forward<_Tp>(__x); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS bit_or
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, _Tp>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef _Tp __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x | __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS bit_or<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) | _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) | _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) | _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS bit_xor
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, _Tp>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef _Tp __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x ^ __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS bit_xor<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) ^ _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) ^ _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) ^ _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+// Comparison operations
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS equal_to
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, bool>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef bool __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x == __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS equal_to<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) == _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) == _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) == _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS not_equal_to
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, bool>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef bool __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x != __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS not_equal_to<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) != _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) != _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) != _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS less
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, bool>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef bool __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x < __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS less<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) < _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) < _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) < _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS less_equal
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, bool>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef bool __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x <= __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS less_equal<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) <= _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) <= _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) <= _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS greater_equal
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, bool>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef bool __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x >= __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS greater_equal<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) >= _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) >= _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) >= _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS greater
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, bool>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef bool __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x > __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS greater<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) > _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) > _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) > _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+// Logical operations
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS logical_and
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, bool>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef bool __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x && __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS logical_and<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) && _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) && _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) && _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS logical_not
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : unary_function<_Tp, bool>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef bool __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Tp& __x) const
+        {return !__x;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS logical_not<void>
+{
+    template <class _Tp>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_Tp&& __x) const
+        noexcept(noexcept(!_VSTD::forward<_Tp>(__x)))
+        -> decltype(      !_VSTD::forward<_Tp>(__x))
+        { return          !_VSTD::forward<_Tp>(__x); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+#if _LIBCPP_STD_VER > 11
+template <class _Tp = void>
+#else
+template <class _Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS logical_or
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<_Tp, _Tp, bool>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    typedef bool __result_type;  // used by valarray
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp second_argument_type;
+#endif
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x || __y;}
+};
+
+#if _LIBCPP_STD_VER > 11
+template <>
+struct _LIBCPP_TEMPLATE_VIS logical_or<void>
+{
+    template <class _T1, class _T2>
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    auto operator()(_T1&& __t, _T2&& __u) const
+        noexcept(noexcept(_VSTD::forward<_T1>(__t) || _VSTD::forward<_T2>(__u)))
+        -> decltype(      _VSTD::forward<_T1>(__t) || _VSTD::forward<_T2>(__u))
+        { return          _VSTD::forward<_T1>(__t) || _VSTD::forward<_T2>(__u); }
+    typedef void is_transparent;
+};
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_OPERATIONS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/perfect_forward.h b/contrib/libs/cxxsupp/libcxx/include/__functional/perfect_forward.h
new file mode 100644
index 00000000000..80a468d57f5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/perfect_forward.h
@@ -0,0 +1,95 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_PERFECT_FORWARD_H
+#define _LIBCPP___FUNCTIONAL_PERFECT_FORWARD_H
+
+#include <__config>
+#include <__utility/declval.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <tuple>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+template <class _Op, class _Indices, class ..._Bound>
+struct __perfect_forward_impl;
+
+template <class _Op, size_t ..._Idx, class ..._Bound>
+struct __perfect_forward_impl<_Op, index_sequence<_Idx...>, _Bound...> {
+private:
+    tuple<_Bound...> __bound_;
+
+public:
+    template <class ..._BoundArgs, class = enable_if_t<
+        is_constructible_v<tuple<_Bound...>, _BoundArgs&&...>
+    >>
+    explicit constexpr __perfect_forward_impl(tuple<>, _BoundArgs&& ...__bound)
+        : __bound_(_VSTD::forward<_BoundArgs>(__bound)...)
+    { }
+
+    __perfect_forward_impl(__perfect_forward_impl const&) = default;
+    __perfect_forward_impl(__perfect_forward_impl&&) = default;
+
+    __perfect_forward_impl& operator=(__perfect_forward_impl const&) = default;
+    __perfect_forward_impl& operator=(__perfect_forward_impl&&) = default;
+
+    template <class ..._Args, class = enable_if_t<is_invocable_v<_Op, _Bound&..., _Args...>>>
+    _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) &
+        noexcept(noexcept(_Op()(_VSTD::get<_Idx>(__bound_)..., _VSTD::forward<_Args>(__args)...)))
+        -> decltype(      _Op()(_VSTD::get<_Idx>(__bound_)..., _VSTD::forward<_Args>(__args)...))
+        { return          _Op()(_VSTD::get<_Idx>(__bound_)..., _VSTD::forward<_Args>(__args)...); }
+
+    template <class ..._Args, class = enable_if_t<!is_invocable_v<_Op, _Bound&..., _Args...>>>
+    auto operator()(_Args&&...) & = delete;
+
+    template <class ..._Args, class = enable_if_t<is_invocable_v<_Op, _Bound const&..., _Args...>>>
+    _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) const&
+        noexcept(noexcept(_Op()(_VSTD::get<_Idx>(__bound_)..., _VSTD::forward<_Args>(__args)...)))
+        -> decltype(      _Op()(_VSTD::get<_Idx>(__bound_)..., _VSTD::forward<_Args>(__args)...))
+        { return          _Op()(_VSTD::get<_Idx>(__bound_)..., _VSTD::forward<_Args>(__args)...); }
+
+    template <class ..._Args, class = enable_if_t<!is_invocable_v<_Op, _Bound const&..., _Args...>>>
+    auto operator()(_Args&&...) const& = delete;
+
+    template <class ..._Args, class = enable_if_t<is_invocable_v<_Op, _Bound..., _Args...>>>
+    _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) &&
+        noexcept(noexcept(_Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_))..., _VSTD::forward<_Args>(__args)...)))
+        -> decltype(      _Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_))..., _VSTD::forward<_Args>(__args)...))
+        { return          _Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_))..., _VSTD::forward<_Args>(__args)...); }
+
+    template <class ..._Args, class = enable_if_t<!is_invocable_v<_Op, _Bound..., _Args...>>>
+    auto operator()(_Args&&...) && = delete;
+
+    template <class ..._Args, class = enable_if_t<is_invocable_v<_Op, _Bound const..., _Args...>>>
+    _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Args&&... __args) const&&
+        noexcept(noexcept(_Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_))..., _VSTD::forward<_Args>(__args)...)))
+        -> decltype(      _Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_))..., _VSTD::forward<_Args>(__args)...))
+        { return          _Op()(_VSTD::get<_Idx>(_VSTD::move(__bound_))..., _VSTD::forward<_Args>(__args)...); }
+
+    template <class ..._Args, class = enable_if_t<!is_invocable_v<_Op, _Bound const..., _Args...>>>
+    auto operator()(_Args&&...) const&& = delete;
+};
+
+// __perfect_forward implements a perfect-forwarding call wrapper as explained in [func.require].
+template <class _Op, class ..._Args>
+using __perfect_forward = __perfect_forward_impl<_Op, index_sequence_for<_Args...>, _Args...>;
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_PERFECT_FORWARD_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/pointer_to_binary_function.h b/contrib/libs/cxxsupp/libcxx/include/__functional/pointer_to_binary_function.h
new file mode 100644
index 00000000000..d4a6c1674ae
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/pointer_to_binary_function.h
@@ -0,0 +1,46 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_POINTER_TO_BINARY_FUNCTION_H
+#define _LIBCPP___FUNCTIONAL_POINTER_TO_BINARY_FUNCTION_H
+
+#include <__config>
+#include <__functional/binary_function.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_BINDERS)
+
+template <class _Arg1, class _Arg2, class _Result>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 pointer_to_binary_function
+    : public binary_function<_Arg1, _Arg2, _Result>
+{
+    _Result (*__f_)(_Arg1, _Arg2);
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit pointer_to_binary_function(_Result (*__f)(_Arg1, _Arg2))
+        : __f_(__f) {}
+    _LIBCPP_INLINE_VISIBILITY _Result operator()(_Arg1 __x, _Arg2 __y) const
+        {return __f_(__x, __y);}
+};
+
+template <class _Arg1, class _Arg2, class _Result>
+_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
+pointer_to_binary_function<_Arg1,_Arg2,_Result>
+ptr_fun(_Result (*__f)(_Arg1,_Arg2))
+    {return pointer_to_binary_function<_Arg1,_Arg2,_Result>(__f);}
+
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_POINTER_TO_BINARY_FUNCTION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/pointer_to_unary_function.h b/contrib/libs/cxxsupp/libcxx/include/__functional/pointer_to_unary_function.h
new file mode 100644
index 00000000000..0ac4561cc30
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/pointer_to_unary_function.h
@@ -0,0 +1,46 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_POINTER_TO_UNARY_FUNCTION_H
+#define _LIBCPP___FUNCTIONAL_POINTER_TO_UNARY_FUNCTION_H
+
+#include <__config>
+#include <__functional/unary_function.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_BINDERS)
+
+template <class _Arg, class _Result>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 pointer_to_unary_function
+    : public unary_function<_Arg, _Result>
+{
+    _Result (*__f_)(_Arg);
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit pointer_to_unary_function(_Result (*__f)(_Arg))
+        : __f_(__f) {}
+    _LIBCPP_INLINE_VISIBILITY _Result operator()(_Arg __x) const
+        {return __f_(__x);}
+};
+
+template <class _Arg, class _Result>
+_LIBCPP_DEPRECATED_IN_CXX11 inline _LIBCPP_INLINE_VISIBILITY
+pointer_to_unary_function<_Arg,_Result>
+ptr_fun(_Result (*__f)(_Arg))
+    {return pointer_to_unary_function<_Arg,_Result>(__f);}
+
+#endif // _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_BINDERS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_POINTER_TO_UNARY_FUNCTION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/ranges_operations.h b/contrib/libs/cxxsupp/libcxx/include/__functional/ranges_operations.h
new file mode 100644
index 00000000000..777c5352510
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/ranges_operations.h
@@ -0,0 +1,97 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_RANGES_OPERATIONS_H
+#define _LIBCPP___FUNCTIONAL_RANGES_OPERATIONS_H
+
+#include <__config>
+#include <concepts>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+namespace ranges {
+
+struct equal_to {
+  template <class _Tp, class _Up>
+  requires equality_comparable_with<_Tp, _Up>
+  [[nodiscard]] constexpr bool operator()(_Tp &&__t, _Up &&__u) const
+      noexcept(noexcept(bool(_VSTD::forward<_Tp>(__t) == _VSTD::forward<_Up>(__u)))) {
+    return _VSTD::forward<_Tp>(__t) == _VSTD::forward<_Up>(__u);
+  }
+
+  using is_transparent = void;
+};
+
+struct not_equal_to {
+  template <class _Tp, class _Up>
+  requires equality_comparable_with<_Tp, _Up>
+  [[nodiscard]] constexpr bool operator()(_Tp &&__t, _Up &&__u) const
+      noexcept(noexcept(bool(!(_VSTD::forward<_Tp>(__t) == _VSTD::forward<_Up>(__u))))) {
+    return !(_VSTD::forward<_Tp>(__t) == _VSTD::forward<_Up>(__u));
+  }
+
+  using is_transparent = void;
+};
+
+struct less {
+  template <class _Tp, class _Up>
+  requires totally_ordered_with<_Tp, _Up>
+  [[nodiscard]] constexpr bool operator()(_Tp &&__t, _Up &&__u) const
+      noexcept(noexcept(bool(_VSTD::forward<_Tp>(__t) < _VSTD::forward<_Up>(__u)))) {
+    return _VSTD::forward<_Tp>(__t) < _VSTD::forward<_Up>(__u);
+  }
+
+  using is_transparent = void;
+};
+
+struct less_equal {
+  template <class _Tp, class _Up>
+  requires totally_ordered_with<_Tp, _Up>
+  [[nodiscard]] constexpr bool operator()(_Tp &&__t, _Up &&__u) const
+      noexcept(noexcept(bool(!(_VSTD::forward<_Up>(__u) < _VSTD::forward<_Tp>(__t))))) {
+    return !(_VSTD::forward<_Up>(__u) < _VSTD::forward<_Tp>(__t));
+  }
+
+  using is_transparent = void;
+};
+
+struct greater {
+  template <class _Tp, class _Up>
+  requires totally_ordered_with<_Tp, _Up>
+  [[nodiscard]] constexpr bool operator()(_Tp &&__t, _Up &&__u) const
+      noexcept(noexcept(bool(_VSTD::forward<_Up>(__u) < _VSTD::forward<_Tp>(__t)))) {
+    return _VSTD::forward<_Up>(__u) < _VSTD::forward<_Tp>(__t);
+  }
+
+  using is_transparent = void;
+};
+
+struct greater_equal {
+  template <class _Tp, class _Up>
+  requires totally_ordered_with<_Tp, _Up>
+  [[nodiscard]] constexpr bool operator()(_Tp &&__t, _Up &&__u) const
+      noexcept(noexcept(bool(!(_VSTD::forward<_Tp>(__t) < _VSTD::forward<_Up>(__u))))) {
+    return !(_VSTD::forward<_Tp>(__t) < _VSTD::forward<_Up>(__u));
+  }
+
+  using is_transparent = void;
+};
+
+} // namespace ranges
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_RANGES_OPERATIONS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/reference_wrapper.h b/contrib/libs/cxxsupp/libcxx/include/__functional/reference_wrapper.h
new file mode 100644
index 00000000000..e1e4abd80c2
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/reference_wrapper.h
@@ -0,0 +1,223 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_REFERENCE_WRAPPER_H
+#define _LIBCPP___FUNCTIONAL_REFERENCE_WRAPPER_H
+
+#include <__config>
+#include <__functional/weak_result_type.h>
+#include <__memory/addressof.h>
+#include <__utility/forward.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS reference_wrapper
+#if _LIBCPP_STD_VER <= 17 || !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : public __weak_result_type<_Tp>
+#endif
+{
+public:
+    // types
+    typedef _Tp type;
+private:
+    type* __f_;
+
+#ifndef _LIBCPP_CXX03_LANG
+    static void __fun(_Tp&) _NOEXCEPT;
+    static void __fun(_Tp&&) = delete;
+#endif
+
+public:
+    // construct/copy/destroy
+#ifdef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    reference_wrapper(type& __f) _NOEXCEPT
+        : __f_(_VSTD::addressof(__f)) {}
+#else
+    template <class _Up, class = __enable_if_t<!__is_same_uncvref<_Up, reference_wrapper>::value, decltype(__fun(declval<_Up>())) >>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    reference_wrapper(_Up&& __u) _NOEXCEPT_(noexcept(__fun(declval<_Up>()))) {
+        type& __f = static_cast<_Up&&>(__u);
+        __f_ = _VSTD::addressof(__f);
+    }
+#endif
+
+    // access
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    operator type&() const _NOEXCEPT {return *__f_;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    type& get() const _NOEXCEPT {return *__f_;}
+
+#ifndef _LIBCPP_CXX03_LANG
+    // invoke
+    template <class... _ArgTypes>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    typename __invoke_of<type&, _ArgTypes...>::type
+    operator() (_ArgTypes&&... __args) const {
+        return _VSTD::__invoke(get(), _VSTD::forward<_ArgTypes>(__args)...);
+    }
+#else
+
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return<type>::type
+    operator() () const {
+        return _VSTD::__invoke(get());
+    }
+
+    template <class _A0>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return0<type, _A0>::type
+    operator() (_A0& __a0) const {
+        return _VSTD::__invoke(get(), __a0);
+    }
+
+    template <class _A0>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return0<type, _A0 const>::type
+    operator() (_A0 const& __a0) const {
+        return _VSTD::__invoke(get(), __a0);
+    }
+
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0, _A1>::type
+    operator() (_A0& __a0, _A1& __a1) const {
+        return _VSTD::__invoke(get(), __a0, __a1);
+    }
+
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0 const, _A1>::type
+    operator() (_A0 const& __a0, _A1& __a1) const {
+        return _VSTD::__invoke(get(), __a0, __a1);
+    }
+
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0, _A1 const>::type
+    operator() (_A0& __a0, _A1 const& __a1) const {
+        return _VSTD::__invoke(get(), __a0, __a1);
+    }
+
+    template <class _A0, class _A1>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return1<type, _A0 const, _A1 const>::type
+    operator() (_A0 const& __a0, _A1 const& __a1) const {
+        return _VSTD::__invoke(get(), __a0, __a1);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1, _A2>::type
+    operator() (_A0& __a0, _A1& __a1, _A2& __a2) const {
+        return _VSTD::__invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1, _A2>::type
+    operator() (_A0 const& __a0, _A1& __a1, _A2& __a2) const {
+        return _VSTD::__invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1 const, _A2>::type
+    operator() (_A0& __a0, _A1 const& __a1, _A2& __a2) const {
+        return _VSTD::__invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1, _A2 const>::type
+    operator() (_A0& __a0, _A1& __a1, _A2 const& __a2) const {
+        return _VSTD::__invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1 const, _A2>::type
+    operator() (_A0 const& __a0, _A1 const& __a1, _A2& __a2) const {
+        return _VSTD::__invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1, _A2 const>::type
+    operator() (_A0 const& __a0, _A1& __a1, _A2 const& __a2) const {
+        return _VSTD::__invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0, _A1 const, _A2 const>::type
+    operator() (_A0& __a0, _A1 const& __a1, _A2 const& __a2) const {
+        return _VSTD::__invoke(get(), __a0, __a1, __a2);
+    }
+
+    template <class _A0, class _A1, class _A2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename __invoke_return2<type, _A0 const, _A1 const, _A2 const>::type
+    operator() (_A0 const& __a0, _A1 const& __a1, _A2 const& __a2) const {
+        return _VSTD::__invoke(get(), __a0, __a1, __a2);
+    }
+#endif // _LIBCPP_CXX03_LANG
+};
+
+#if _LIBCPP_STD_VER >= 17
+template <class _Tp>
+reference_wrapper(_Tp&) -> reference_wrapper<_Tp>;
+#endif
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+reference_wrapper<_Tp>
+ref(_Tp& __t) _NOEXCEPT
+{
+    return reference_wrapper<_Tp>(__t);
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+reference_wrapper<_Tp>
+ref(reference_wrapper<_Tp> __t) _NOEXCEPT
+{
+    return _VSTD::ref(__t.get());
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+reference_wrapper<const _Tp>
+cref(const _Tp& __t) _NOEXCEPT
+{
+    return reference_wrapper<const _Tp>(__t);
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+reference_wrapper<const _Tp>
+cref(reference_wrapper<_Tp> __t) _NOEXCEPT
+{
+    return _VSTD::cref(__t.get());
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp> void ref(const _Tp&&) = delete;
+template <class _Tp> void cref(const _Tp&&) = delete;
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_REFERENCE_WRAPPER_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/unary_function.h b/contrib/libs/cxxsupp/libcxx/include/__functional/unary_function.h
new file mode 100644
index 00000000000..499f9964676
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/unary_function.h
@@ -0,0 +1,29 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_UNARY_FUNCTION_H
+#define _LIBCPP___FUNCTIONAL_UNARY_FUNCTION_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Arg, class _Result>
+struct _LIBCPP_TEMPLATE_VIS unary_function
+{
+    typedef _Arg    argument_type;
+    typedef _Result result_type;
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_UNARY_FUNCTION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/unary_negate.h b/contrib/libs/cxxsupp/libcxx/include/__functional/unary_negate.h
new file mode 100644
index 00000000000..71257cf40c0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/unary_negate.h
@@ -0,0 +1,47 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_UNARY_NEGATE_H
+#define _LIBCPP___FUNCTIONAL_UNARY_NEGATE_H
+
+#include <__config>
+#include <__functional/unary_function.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_NEGATORS)
+
+template <class _Predicate>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 unary_negate
+    : public unary_function<typename _Predicate::argument_type, bool>
+{
+    _Predicate __pred_;
+public:
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    explicit unary_negate(const _Predicate& __pred)
+        : __pred_(__pred) {}
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const typename _Predicate::argument_type& __x) const
+        {return !__pred_(__x);}
+};
+
+template <class _Predicate>
+_LIBCPP_DEPRECATED_IN_CXX17 inline _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+unary_negate<_Predicate>
+not1(const _Predicate& __pred) {return unary_negate<_Predicate>(__pred);}
+
+#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_NEGATORS)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_UNARY_NEGATE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/unwrap_ref.h b/contrib/libs/cxxsupp/libcxx/include/__functional/unwrap_ref.h
new file mode 100644
index 00000000000..dc309add90d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/unwrap_ref.h
@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_UNWRAP_REF_H
+#define _LIBCPP___FUNCTIONAL_UNWRAP_REF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+struct __unwrap_reference { typedef _LIBCPP_NODEBUG _Tp type; };
+
+template <class _Tp>
+class reference_wrapper;
+
+template <class _Tp>
+struct __unwrap_reference<reference_wrapper<_Tp> > { typedef _LIBCPP_NODEBUG _Tp& type; };
+
+template <class _Tp>
+struct decay;
+
+#if _LIBCPP_STD_VER > 17
+template <class _Tp>
+struct unwrap_reference : __unwrap_reference<_Tp> { };
+
+template <class _Tp>
+using unwrap_reference_t = typename unwrap_reference<_Tp>::type;
+
+template <class _Tp>
+struct unwrap_ref_decay : unwrap_reference<typename decay<_Tp>::type> { };
+
+template <class _Tp>
+using unwrap_ref_decay_t = typename unwrap_ref_decay<_Tp>::type;
+#endif // > C++17
+
+template <class _Tp>
+struct __unwrap_ref_decay
+#if _LIBCPP_STD_VER > 17
+    : unwrap_ref_decay<_Tp>
+#else
+    : __unwrap_reference<typename decay<_Tp>::type>
+#endif
+{ };
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_UNWRAP_REF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional/weak_result_type.h b/contrib/libs/cxxsupp/libcxx/include/__functional/weak_result_type.h
new file mode 100644
index 00000000000..288c2ad49a5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional/weak_result_type.h
@@ -0,0 +1,482 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_WEAK_RESULT_TYPE_H
+#define _LIBCPP___FUNCTIONAL_WEAK_RESULT_TYPE_H
+
+#include <__config>
+#include <__functional/binary_function.h>
+#include <__functional/unary_function.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+struct __has_result_type
+{
+private:
+    struct __two {char __lx; char __lxx;};
+    template <class _Up> static __two __test(...);
+    // Fix for MSVC which allows to reference private types. Wrap into declval to prevent that.
+    template <class _Up> static char __test(decltype(std::declval<typename _Up::result_type*>()) = 0);
+public:
+    static const bool value = sizeof(__test<_Tp>(0)) == 1;
+};
+
+// __weak_result_type
+
+template <class _Tp>
+struct __derives_from_unary_function
+{
+private:
+    struct __two {char __lx; char __lxx;};
+    static __two __test(...);
+    template <class _Ap, class _Rp>
+        static unary_function<_Ap, _Rp>
+        __test(const volatile unary_function<_Ap, _Rp>*);
+public:
+    static const bool value = !is_same<decltype(__test((_Tp*)0)), __two>::value;
+    typedef decltype(__test((_Tp*)0)) type;
+};
+
+template <class _Tp>
+struct __derives_from_binary_function
+{
+private:
+    struct __two {char __lx; char __lxx;};
+    static __two __test(...);
+    template <class _A1, class _A2, class _Rp>
+        static binary_function<_A1, _A2, _Rp>
+        __test(const volatile binary_function<_A1, _A2, _Rp>*);
+public:
+    static const bool value = !is_same<decltype(__test((_Tp*)0)), __two>::value;
+    typedef decltype(__test((_Tp*)0)) type;
+};
+
+template <class _Tp, bool = __derives_from_unary_function<_Tp>::value>
+struct __maybe_derive_from_unary_function  // bool is true
+    : public __derives_from_unary_function<_Tp>::type
+{
+};
+
+template <class _Tp>
+struct __maybe_derive_from_unary_function<_Tp, false>
+{
+};
+
+template <class _Tp, bool = __derives_from_binary_function<_Tp>::value>
+struct __maybe_derive_from_binary_function  // bool is true
+    : public __derives_from_binary_function<_Tp>::type
+{
+};
+
+template <class _Tp>
+struct __maybe_derive_from_binary_function<_Tp, false>
+{
+};
+
+template <class _Tp, bool = __has_result_type<_Tp>::value>
+struct __weak_result_type_imp // bool is true
+    : public __maybe_derive_from_unary_function<_Tp>,
+      public __maybe_derive_from_binary_function<_Tp>
+{
+    typedef _LIBCPP_NODEBUG typename _Tp::result_type result_type;
+};
+
+template <class _Tp>
+struct __weak_result_type_imp<_Tp, false>
+    : public __maybe_derive_from_unary_function<_Tp>,
+      public __maybe_derive_from_binary_function<_Tp>
+{
+};
+
+template <class _Tp>
+struct __weak_result_type
+    : public __weak_result_type_imp<_Tp>
+{
+};
+
+// 0 argument case
+
+template <class _Rp>
+struct __weak_result_type<_Rp ()>
+{
+    typedef _LIBCPP_NODEBUG _Rp result_type;
+};
+
+template <class _Rp>
+struct __weak_result_type<_Rp (&)()>
+{
+    typedef _LIBCPP_NODEBUG _Rp result_type;
+};
+
+template <class _Rp>
+struct __weak_result_type<_Rp (*)()>
+{
+    typedef _LIBCPP_NODEBUG _Rp result_type;
+};
+
+// 1 argument case
+
+template <class _Rp, class _A1>
+struct __weak_result_type<_Rp (_A1)>
+    : public unary_function<_A1, _Rp>
+{
+};
+
+template <class _Rp, class _A1>
+struct __weak_result_type<_Rp (&)(_A1)>
+    : public unary_function<_A1, _Rp>
+{
+};
+
+template <class _Rp, class _A1>
+struct __weak_result_type<_Rp (*)(_A1)>
+    : public unary_function<_A1, _Rp>
+{
+};
+
+template <class _Rp, class _Cp>
+struct __weak_result_type<_Rp (_Cp::*)()>
+    : public unary_function<_Cp*, _Rp>
+{
+};
+
+template <class _Rp, class _Cp>
+struct __weak_result_type<_Rp (_Cp::*)() const>
+    : public unary_function<const _Cp*, _Rp>
+{
+};
+
+template <class _Rp, class _Cp>
+struct __weak_result_type<_Rp (_Cp::*)() volatile>
+    : public unary_function<volatile _Cp*, _Rp>
+{
+};
+
+template <class _Rp, class _Cp>
+struct __weak_result_type<_Rp (_Cp::*)() const volatile>
+    : public unary_function<const volatile _Cp*, _Rp>
+{
+};
+
+// 2 argument case
+
+template <class _Rp, class _A1, class _A2>
+struct __weak_result_type<_Rp (_A1, _A2)>
+    : public binary_function<_A1, _A2, _Rp>
+{
+};
+
+template <class _Rp, class _A1, class _A2>
+struct __weak_result_type<_Rp (*)(_A1, _A2)>
+    : public binary_function<_A1, _A2, _Rp>
+{
+};
+
+template <class _Rp, class _A1, class _A2>
+struct __weak_result_type<_Rp (&)(_A1, _A2)>
+    : public binary_function<_A1, _A2, _Rp>
+{
+};
+
+template <class _Rp, class _Cp, class _A1>
+struct __weak_result_type<_Rp (_Cp::*)(_A1)>
+    : public binary_function<_Cp*, _A1, _Rp>
+{
+};
+
+template <class _Rp, class _Cp, class _A1>
+struct __weak_result_type<_Rp (_Cp::*)(_A1) const>
+    : public binary_function<const _Cp*, _A1, _Rp>
+{
+};
+
+template <class _Rp, class _Cp, class _A1>
+struct __weak_result_type<_Rp (_Cp::*)(_A1) volatile>
+    : public binary_function<volatile _Cp*, _A1, _Rp>
+{
+};
+
+template <class _Rp, class _Cp, class _A1>
+struct __weak_result_type<_Rp (_Cp::*)(_A1) const volatile>
+    : public binary_function<const volatile _Cp*, _A1, _Rp>
+{
+};
+
+
+#ifndef _LIBCPP_CXX03_LANG
+// 3 or more arguments
+
+template <class _Rp, class _A1, class _A2, class _A3, class ..._A4>
+struct __weak_result_type<_Rp (_A1, _A2, _A3, _A4...)>
+{
+    typedef _Rp result_type;
+};
+
+template <class _Rp, class _A1, class _A2, class _A3, class ..._A4>
+struct __weak_result_type<_Rp (&)(_A1, _A2, _A3, _A4...)>
+{
+    typedef _Rp result_type;
+};
+
+template <class _Rp, class _A1, class _A2, class _A3, class ..._A4>
+struct __weak_result_type<_Rp (*)(_A1, _A2, _A3, _A4...)>
+{
+    typedef _Rp result_type;
+};
+
+template <class _Rp, class _Cp, class _A1, class _A2, class ..._A3>
+struct __weak_result_type<_Rp (_Cp::*)(_A1, _A2, _A3...)>
+{
+    typedef _Rp result_type;
+};
+
+template <class _Rp, class _Cp, class _A1, class _A2, class ..._A3>
+struct __weak_result_type<_Rp (_Cp::*)(_A1, _A2, _A3...) const>
+{
+    typedef _Rp result_type;
+};
+
+template <class _Rp, class _Cp, class _A1, class _A2, class ..._A3>
+struct __weak_result_type<_Rp (_Cp::*)(_A1, _A2, _A3...) volatile>
+{
+    typedef _Rp result_type;
+};
+
+template <class _Rp, class _Cp, class _A1, class _A2, class ..._A3>
+struct __weak_result_type<_Rp (_Cp::*)(_A1, _A2, _A3...) const volatile>
+{
+    typedef _Rp result_type;
+};
+
+template <class _Tp, class ..._Args>
+struct __invoke_return
+{
+    typedef decltype(_VSTD::__invoke(declval<_Tp>(), declval<_Args>()...)) type;
+};
+
+#else // defined(_LIBCPP_CXX03_LANG)
+
+template <class _Ret, class _T1, bool _IsFunc, bool _IsBase>
+struct __enable_invoke_imp;
+
+template <class _Ret, class _T1>
+struct __enable_invoke_imp<_Ret, _T1, true, true> {
+    typedef _Ret _Bullet1;
+    typedef _Bullet1 type;
+};
+
+template <class _Ret, class _T1>
+struct __enable_invoke_imp<_Ret, _T1, true, false>  {
+    typedef _Ret _Bullet2;
+    typedef _Bullet2 type;
+};
+
+template <class _Ret, class _T1>
+struct __enable_invoke_imp<_Ret, _T1, false, true>  {
+    typedef typename add_lvalue_reference<
+                typename __apply_cv<_T1, _Ret>::type
+            >::type _Bullet3;
+    typedef _Bullet3 type;
+};
+
+template <class _Ret, class _T1>
+struct __enable_invoke_imp<_Ret, _T1, false, false>  {
+    typedef typename add_lvalue_reference<
+                typename __apply_cv<decltype(*declval<_T1>()), _Ret>::type
+            >::type _Bullet4;
+    typedef _Bullet4 type;
+};
+
+template <class _Ret, class _T1>
+struct __enable_invoke_imp<_Ret, _T1*, false, false>  {
+    typedef typename add_lvalue_reference<
+                typename __apply_cv<_T1, _Ret>::type
+            >::type _Bullet4;
+    typedef _Bullet4  type;
+};
+
+template <class _Fn, class _T1,
+          class _Traits = __member_pointer_traits<_Fn>,
+          class _Ret = typename _Traits::_ReturnType,
+          class _Class = typename _Traits::_ClassType>
+struct __enable_invoke : __enable_invoke_imp<
+    _Ret, _T1,
+    is_member_function_pointer<_Fn>::value,
+    is_base_of<_Class, typename remove_reference<_T1>::type>::value>
+{
+};
+
+__nat __invoke(__any, ...);
+
+// first bullet
+
+template <class _Fn, class _T1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __enable_invoke<_Fn, _T1>::_Bullet1
+__invoke(_Fn __f, _T1& __t1) {
+    return (__t1.*__f)();
+}
+
+template <class _Fn, class _T1, class _A0>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __enable_invoke<_Fn, _T1>::_Bullet1
+__invoke(_Fn __f, _T1& __t1, _A0& __a0) {
+    return (__t1.*__f)(__a0);
+}
+
+template <class _Fn, class _T1, class _A0, class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __enable_invoke<_Fn, _T1>::_Bullet1
+__invoke(_Fn __f, _T1& __t1, _A0& __a0, _A1& __a1) {
+    return (__t1.*__f)(__a0, __a1);
+}
+
+template <class _Fn, class _T1, class _A0, class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __enable_invoke<_Fn, _T1>::_Bullet1
+__invoke(_Fn __f, _T1& __t1, _A0& __a0, _A1& __a1, _A2& __a2) {
+    return (__t1.*__f)(__a0, __a1, __a2);
+}
+
+template <class _Fn, class _T1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __enable_invoke<_Fn, _T1>::_Bullet2
+__invoke(_Fn __f, _T1& __t1) {
+    return ((*__t1).*__f)();
+}
+
+template <class _Fn, class _T1, class _A0>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __enable_invoke<_Fn, _T1>::_Bullet2
+__invoke(_Fn __f, _T1& __t1, _A0& __a0) {
+    return ((*__t1).*__f)(__a0);
+}
+
+template <class _Fn, class _T1, class _A0, class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __enable_invoke<_Fn, _T1>::_Bullet2
+__invoke(_Fn __f, _T1& __t1, _A0& __a0, _A1& __a1) {
+    return ((*__t1).*__f)(__a0, __a1);
+}
+
+template <class _Fn, class _T1, class _A0, class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __enable_invoke<_Fn, _T1>::_Bullet2
+__invoke(_Fn __f, _T1& __t1, _A0& __a0, _A1& __a1, _A2& __a2) {
+    return ((*__t1).*__f)(__a0, __a1, __a2);
+}
+
+template <class _Fn, class _T1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __enable_invoke<_Fn, _T1>::_Bullet3
+__invoke(_Fn __f, _T1& __t1) {
+    return __t1.*__f;
+}
+
+template <class _Fn, class _T1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __enable_invoke<_Fn, _T1>::_Bullet4
+__invoke(_Fn __f, _T1& __t1) {
+    return (*__t1).*__f;
+}
+
+// fifth bullet
+
+template <class _Fp>
+inline _LIBCPP_INLINE_VISIBILITY
+decltype(declval<_Fp&>()())
+__invoke(_Fp& __f)
+{
+    return __f();
+}
+
+template <class _Fp, class _A0>
+inline _LIBCPP_INLINE_VISIBILITY
+decltype(declval<_Fp&>()(declval<_A0&>()))
+__invoke(_Fp& __f, _A0& __a0)
+{
+    return __f(__a0);
+}
+
+template <class _Fp, class _A0, class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+decltype(declval<_Fp&>()(declval<_A0&>(), declval<_A1&>()))
+__invoke(_Fp& __f, _A0& __a0, _A1& __a1)
+{
+    return __f(__a0, __a1);
+}
+
+template <class _Fp, class _A0, class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+decltype(declval<_Fp&>()(declval<_A0&>(), declval<_A1&>(), declval<_A2&>()))
+__invoke(_Fp& __f, _A0& __a0, _A1& __a1, _A2& __a2)
+{
+    return __f(__a0, __a1, __a2);
+}
+
+template <class _Fp, bool = __has_result_type<__weak_result_type<_Fp> >::value>
+struct __invoke_return
+{
+    typedef typename __weak_result_type<_Fp>::result_type type;
+};
+
+template <class _Fp>
+struct __invoke_return<_Fp, false>
+{
+    typedef decltype(_VSTD::__invoke(declval<_Fp&>())) type;
+};
+
+template <class _Tp, class _A0>
+struct __invoke_return0
+{
+    typedef decltype(_VSTD::__invoke(declval<_Tp&>(), declval<_A0&>())) type;
+};
+
+template <class _Rp, class _Tp, class _A0>
+struct __invoke_return0<_Rp _Tp::*, _A0>
+{
+    typedef typename __enable_invoke<_Rp _Tp::*, _A0>::type type;
+};
+
+template <class _Tp, class _A0, class _A1>
+struct __invoke_return1
+{
+    typedef decltype(_VSTD::__invoke(declval<_Tp&>(), declval<_A0&>(),
+                                                      declval<_A1&>())) type;
+};
+
+template <class _Rp, class _Class, class _A0, class _A1>
+struct __invoke_return1<_Rp _Class::*, _A0, _A1> {
+    typedef typename __enable_invoke<_Rp _Class::*, _A0>::type type;
+};
+
+template <class _Tp, class _A0, class _A1, class _A2>
+struct __invoke_return2
+{
+    typedef decltype(_VSTD::__invoke(declval<_Tp&>(), declval<_A0&>(),
+                                                      declval<_A1&>(),
+                                                      declval<_A2&>())) type;
+};
+
+template <class _Ret, class _Class, class _A0, class _A1, class _A2>
+struct __invoke_return2<_Ret _Class::*, _A0, _A1, _A2> {
+    typedef typename __enable_invoke<_Ret _Class::*, _A0>::type type;
+};
+
+#endif // !defined(_LIBCPP_CXX03_LANG)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_WEAK_RESULT_TYPE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__functional_base b/contrib/libs/cxxsupp/libcxx/include/__functional_base
new file mode 100644
index 00000000000..ccc3f3a58ca
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__functional_base
@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_FUNCTIONAL_BASE
+#define _LIBCPP_FUNCTIONAL_BASE
+
+#include <__config>
+#include <__functional/binary_function.h>
+#include <__functional/invoke.h>
+#include <__functional/operations.h>
+#include <__functional/reference_wrapper.h>
+#include <__functional/unary_function.h>
+#include <__functional/weak_result_type.h>
+#include <__memory/allocator_arg_t.h>
+#include <__memory/uses_allocator.h>
+#include <exception>
+#include <new>
+#include <type_traits>
+#include <typeinfo>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#endif // _LIBCPP_FUNCTIONAL_BASE
diff --git a/contrib/libs/cxxsupp/libcxx/include/__hash_table b/contrib/libs/cxxsupp/libcxx/include/__hash_table
new file mode 100644
index 00000000000..bd97027c1a0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__hash_table
@@ -0,0 +1,2820 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP__HASH_TABLE
+#define _LIBCPP__HASH_TABLE
+
+#include <__bits> // __libcpp_clz
+#include <__config>
+#include <__debug>
+#include <algorithm>
+#include <cmath>
+#include <initializer_list>
+#include <iterator>
+#include <memory>
+#include <type_traits>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Key, class _Tp>
+struct __hash_value_type;
+
+template <class _Tp>
+struct __is_hash_value_type_imp : false_type {};
+
+template <class _Key, class _Value>
+struct __is_hash_value_type_imp<__hash_value_type<_Key, _Value> > : true_type {};
+
+template <class ..._Args>
+struct __is_hash_value_type : false_type {};
+
+template <class _One>
+struct __is_hash_value_type<_One> : __is_hash_value_type_imp<typename __uncvref<_One>::type> {};
+
+_LIBCPP_FUNC_VIS
+size_t __next_prime(size_t __n);
+
+template <class _NodePtr>
+struct __hash_node_base
+{
+    typedef typename pointer_traits<_NodePtr>::element_type __node_type;
+    typedef __hash_node_base __first_node;
+    typedef typename __rebind_pointer<_NodePtr, __first_node>::type __node_base_pointer;
+    typedef _NodePtr __node_pointer;
+
+#if defined(_LIBCPP_ABI_FIX_UNORDERED_NODE_POINTER_UB)
+  typedef __node_base_pointer __next_pointer;
+#else
+  typedef typename conditional<
+      is_pointer<__node_pointer>::value,
+      __node_base_pointer,
+      __node_pointer>::type   __next_pointer;
+#endif
+
+    __next_pointer    __next_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __next_pointer __ptr() _NOEXCEPT {
+        return static_cast<__next_pointer>(
+            pointer_traits<__node_base_pointer>::pointer_to(*this));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __node_pointer __upcast() _NOEXCEPT {
+        return static_cast<__node_pointer>(
+            pointer_traits<__node_base_pointer>::pointer_to(*this));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t __hash() const _NOEXCEPT {
+        return static_cast<__node_type const&>(*this).__hash_;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __hash_node_base() _NOEXCEPT : __next_(nullptr) {}
+};
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning( push )
+#pragma warning( disable: 4624 )
+#endif // _LIBCPP_COMPILER_MSVC
+template <class _Tp, class _VoidPtr>
+struct _LIBCPP_STANDALONE_DEBUG __hash_node
+    : public __hash_node_base
+             <
+                 typename __rebind_pointer<_VoidPtr, __hash_node<_Tp, _VoidPtr> >::type
+             >
+{
+    typedef _Tp __node_value_type;
+
+    size_t            __hash_;
+    __node_value_type __value_;
+};
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning( pop )
+#endif // _LIBCPP_COMPILER_MSVC
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+__is_hash_power2(size_t __bc)
+{
+    return __bc > 2 && !(__bc & (__bc - 1));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+size_t
+__constrain_hash(size_t __h, size_t __bc)
+{
+    return !(__bc & (__bc - 1)) ? __h & (__bc - 1) :
+        (__h < __bc ? __h : __h % __bc);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+size_t
+__next_hash_pow2(size_t __n)
+{
+    return __n < 2 ? __n : (size_t(1) << (numeric_limits<size_t>::digits - __libcpp_clz(__n-1)));
+}
+
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc> class __hash_table;
+
+template <class _NodePtr>      class _LIBCPP_TEMPLATE_VIS __hash_iterator;
+template <class _ConstNodePtr> class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
+template <class _NodePtr>      class _LIBCPP_TEMPLATE_VIS __hash_local_iterator;
+template <class _ConstNodePtr> class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
+template <class _HashIterator> class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
+template <class _HashIterator> class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
+
+template <class _Tp>
+struct __hash_key_value_types {
+  static_assert(!is_reference<_Tp>::value && !is_const<_Tp>::value, "");
+  typedef _Tp key_type;
+  typedef _Tp __node_value_type;
+  typedef _Tp __container_value_type;
+  static const bool __is_map = false;
+
+  _LIBCPP_INLINE_VISIBILITY
+  static key_type const& __get_key(_Tp const& __v) {
+    return __v;
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  static __container_value_type const& __get_value(__node_value_type const& __v) {
+    return __v;
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  static __container_value_type* __get_ptr(__node_value_type& __n) {
+    return _VSTD::addressof(__n);
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  static __container_value_type&& __move(__node_value_type& __v) {
+    return _VSTD::move(__v);
+  }
+};
+
+template <class _Key, class _Tp>
+struct __hash_key_value_types<__hash_value_type<_Key, _Tp> > {
+  typedef _Key                                         key_type;
+  typedef _Tp                                          mapped_type;
+  typedef __hash_value_type<_Key, _Tp>                 __node_value_type;
+  typedef pair<const _Key, _Tp>                        __container_value_type;
+  typedef __container_value_type                       __map_value_type;
+  static const bool __is_map = true;
+
+  _LIBCPP_INLINE_VISIBILITY
+  static key_type const& __get_key(__container_value_type const& __v) {
+    return __v.first;
+  }
+
+  template <class _Up>
+  _LIBCPP_INLINE_VISIBILITY
+  static typename enable_if<__is_same_uncvref<_Up, __node_value_type>::value,
+      __container_value_type const&>::type
+  __get_value(_Up& __t) {
+    return __t.__get_value();
+  }
+
+  template <class _Up>
+  _LIBCPP_INLINE_VISIBILITY
+  static typename enable_if<__is_same_uncvref<_Up, __container_value_type>::value,
+      __container_value_type const&>::type
+  __get_value(_Up& __t) {
+    return __t;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  static __container_value_type* __get_ptr(__node_value_type& __n) {
+    return _VSTD::addressof(__n.__get_value());
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  static pair<key_type&&, mapped_type&&> __move(__node_value_type& __v) {
+    return __v.__move();
+  }
+};
+
+template <class _Tp, class _AllocPtr, class _KVTypes = __hash_key_value_types<_Tp>,
+          bool = _KVTypes::__is_map>
+struct __hash_map_pointer_types {};
+
+template <class _Tp, class _AllocPtr, class _KVTypes>
+struct __hash_map_pointer_types<_Tp, _AllocPtr, _KVTypes, true> {
+  typedef typename _KVTypes::__map_value_type   _Mv;
+  typedef typename __rebind_pointer<_AllocPtr, _Mv>::type
+                                                       __map_value_type_pointer;
+  typedef typename __rebind_pointer<_AllocPtr, const _Mv>::type
+                                                 __const_map_value_type_pointer;
+};
+
+template <class _NodePtr, class _NodeT = typename pointer_traits<_NodePtr>::element_type>
+struct __hash_node_types;
+
+template <class _NodePtr, class _Tp, class _VoidPtr>
+struct __hash_node_types<_NodePtr, __hash_node<_Tp, _VoidPtr> >
+    : public __hash_key_value_types<_Tp>, __hash_map_pointer_types<_Tp, _VoidPtr>
+
+{
+  typedef __hash_key_value_types<_Tp>           __base;
+
+public:
+  typedef ptrdiff_t difference_type;
+  typedef size_t size_type;
+
+  typedef typename __rebind_pointer<_NodePtr, void>::type       __void_pointer;
+
+  typedef typename pointer_traits<_NodePtr>::element_type       __node_type;
+  typedef _NodePtr                                              __node_pointer;
+
+  typedef __hash_node_base<__node_pointer>                      __node_base_type;
+  typedef typename __rebind_pointer<_NodePtr, __node_base_type>::type
+                                                             __node_base_pointer;
+
+  typedef typename __node_base_type::__next_pointer          __next_pointer;
+
+  typedef _Tp                                                 __node_value_type;
+  typedef typename __rebind_pointer<_VoidPtr, __node_value_type>::type
+                                                      __node_value_type_pointer;
+  typedef typename __rebind_pointer<_VoidPtr, const __node_value_type>::type
+                                                __const_node_value_type_pointer;
+
+private:
+    static_assert(!is_const<__node_type>::value,
+                "_NodePtr should never be a pointer to const");
+    static_assert((is_same<typename pointer_traits<_VoidPtr>::element_type, void>::value),
+                  "_VoidPtr does not point to unqualified void type");
+    static_assert((is_same<typename __rebind_pointer<_VoidPtr, __node_type>::type,
+                          _NodePtr>::value), "_VoidPtr does not rebind to _NodePtr.");
+};
+
+template <class _HashIterator>
+struct __hash_node_types_from_iterator;
+template <class _NodePtr>
+struct __hash_node_types_from_iterator<__hash_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
+template <class _NodePtr>
+struct __hash_node_types_from_iterator<__hash_const_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
+template <class _NodePtr>
+struct __hash_node_types_from_iterator<__hash_local_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
+template <class _NodePtr>
+struct __hash_node_types_from_iterator<__hash_const_local_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
+
+
+template <class _NodeValueTp, class _VoidPtr>
+struct __make_hash_node_types {
+  typedef __hash_node<_NodeValueTp, _VoidPtr> _NodeTp;
+  typedef typename __rebind_pointer<_VoidPtr, _NodeTp>::type _NodePtr;
+  typedef __hash_node_types<_NodePtr> type;
+};
+
+template <class _NodePtr>
+class _LIBCPP_TEMPLATE_VIS __hash_iterator
+{
+    typedef __hash_node_types<_NodePtr> _NodeTypes;
+    typedef _NodePtr                            __node_pointer;
+    typedef typename _NodeTypes::__next_pointer __next_pointer;
+
+    __next_pointer            __node_;
+
+public:
+    typedef forward_iterator_tag                           iterator_category;
+    typedef typename _NodeTypes::__node_value_type         value_type;
+    typedef typename _NodeTypes::difference_type           difference_type;
+    typedef value_type&                                    reference;
+    typedef typename _NodeTypes::__node_value_type_pointer pointer;
+
+    _LIBCPP_INLINE_VISIBILITY __hash_iterator() _NOEXCEPT : __node_(nullptr) {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_i(this);
+#endif
+    }
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_iterator(const __hash_iterator& __i)
+        : __node_(__i.__node_)
+    {
+        __get_db()->__iterator_copy(this, _VSTD::addressof(__i));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~__hash_iterator()
+    {
+        __get_db()->__erase_i(this);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_iterator& operator=(const __hash_iterator& __i)
+    {
+        if (this != &__i)
+        {
+            __get_db()->__iterator_copy(this, &__i);
+            __node_ = __i.__node_;
+        }
+        return *this;
+    }
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {
+        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
+                             "Attempted to dereference a non-dereferenceable unordered container iterator");
+        return __node_->__upcast()->__value_;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {
+        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
+                           "Attempted to dereference a non-dereferenceable unordered container iterator");
+        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_iterator& operator++() {
+        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to increment a non-incrementable unordered container iterator");
+        __node_ = __node_->__next_;
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_iterator operator++(int)
+    {
+        __hash_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __hash_iterator& __x, const __hash_iterator& __y)
+    {
+        return __x.__node_ == __y.__node_;
+    }
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __hash_iterator& __x, const __hash_iterator& __y)
+        {return !(__x == __y);}
+
+private:
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_iterator(__next_pointer __node, const void* __c) _NOEXCEPT
+        : __node_(__node)
+        {
+            __get_db()->__insert_ic(this, __c);
+        }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_iterator(__next_pointer __node) _NOEXCEPT
+        : __node_(__node)
+        {}
+#endif
+    template <class, class, class, class> friend class __hash_table;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
+};
+
+template <class _NodePtr>
+class _LIBCPP_TEMPLATE_VIS __hash_const_iterator
+{
+    static_assert(!is_const<typename pointer_traits<_NodePtr>::element_type>::value, "");
+    typedef __hash_node_types<_NodePtr> _NodeTypes;
+    typedef _NodePtr                            __node_pointer;
+    typedef typename _NodeTypes::__next_pointer __next_pointer;
+
+    __next_pointer __node_;
+
+public:
+    typedef __hash_iterator<_NodePtr> __non_const_iterator;
+
+    typedef forward_iterator_tag                                 iterator_category;
+    typedef typename _NodeTypes::__node_value_type               value_type;
+    typedef typename _NodeTypes::difference_type                 difference_type;
+    typedef const value_type&                                    reference;
+    typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
+
+
+    _LIBCPP_INLINE_VISIBILITY __hash_const_iterator() _NOEXCEPT : __node_(nullptr) {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_i(this);
+#endif
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_iterator(const __non_const_iterator& __x) _NOEXCEPT
+        : __node_(__x.__node_)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__iterator_copy(this, &__x);
+#endif
+    }
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_iterator(const __hash_const_iterator& __i)
+        : __node_(__i.__node_)
+    {
+        __get_db()->__iterator_copy(this, &__i);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~__hash_const_iterator()
+    {
+        __get_db()->__erase_i(this);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_iterator& operator=(const __hash_const_iterator& __i)
+    {
+        if (this != &__i)
+        {
+            __get_db()->__iterator_copy(this, &__i);
+            __node_ = __i.__node_;
+        }
+        return *this;
+    }
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {
+        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
+                           "Attempted to dereference a non-dereferenceable unordered container const_iterator");
+        return __node_->__upcast()->__value_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {
+        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
+                           "Attempted to dereference a non-dereferenceable unordered container const_iterator");
+        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_iterator& operator++() {
+        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
+                             "Attempted to increment a non-incrementable unordered container const_iterator");
+        __node_ = __node_->__next_;
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_iterator operator++(int)
+    {
+        __hash_const_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __hash_const_iterator& __x, const __hash_const_iterator& __y)
+    {
+        return __x.__node_ == __y.__node_;
+    }
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __hash_const_iterator& __x, const __hash_const_iterator& __y)
+        {return !(__x == __y);}
+
+private:
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_iterator(__next_pointer __node, const void* __c) _NOEXCEPT
+        : __node_(__node)
+        {
+            __get_db()->__insert_ic(this, __c);
+        }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_iterator(__next_pointer __node) _NOEXCEPT
+        : __node_(__node)
+        {}
+#endif
+    template <class, class, class, class> friend class __hash_table;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
+};
+
+template <class _NodePtr>
+class _LIBCPP_TEMPLATE_VIS __hash_local_iterator
+{
+    typedef __hash_node_types<_NodePtr> _NodeTypes;
+    typedef _NodePtr                            __node_pointer;
+    typedef typename _NodeTypes::__next_pointer __next_pointer;
+
+    __next_pointer         __node_;
+    size_t                 __bucket_;
+    size_t                 __bucket_count_;
+
+public:
+    typedef forward_iterator_tag                                iterator_category;
+    typedef typename _NodeTypes::__node_value_type              value_type;
+    typedef typename _NodeTypes::difference_type                difference_type;
+    typedef value_type&                                         reference;
+    typedef typename _NodeTypes::__node_value_type_pointer      pointer;
+
+    _LIBCPP_INLINE_VISIBILITY __hash_local_iterator() _NOEXCEPT : __node_(nullptr) {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_i(this);
+#endif
+    }
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_local_iterator(const __hash_local_iterator& __i)
+        : __node_(__i.__node_),
+          __bucket_(__i.__bucket_),
+          __bucket_count_(__i.__bucket_count_)
+    {
+        __get_db()->__iterator_copy(this, &__i);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~__hash_local_iterator()
+    {
+        __get_db()->__erase_i(this);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_local_iterator& operator=(const __hash_local_iterator& __i)
+    {
+        if (this != &__i)
+        {
+            __get_db()->__iterator_copy(this, &__i);
+            __node_ = __i.__node_;
+            __bucket_ = __i.__bucket_;
+            __bucket_count_ = __i.__bucket_count_;
+        }
+        return *this;
+    }
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {
+        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
+                           "Attempted to dereference a non-dereferenceable unordered container local_iterator");
+        return __node_->__upcast()->__value_;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {
+        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
+                             "Attempted to dereference a non-dereferenceable unordered container local_iterator");
+        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_local_iterator& operator++() {
+        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to increment a non-incrementable unordered container local_iterator");
+        __node_ = __node_->__next_;
+        if (__node_ != nullptr && __constrain_hash(__node_->__hash(), __bucket_count_) != __bucket_)
+            __node_ = nullptr;
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_local_iterator operator++(int)
+    {
+        __hash_local_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __hash_local_iterator& __x, const __hash_local_iterator& __y)
+    {
+        return __x.__node_ == __y.__node_;
+    }
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __hash_local_iterator& __x, const __hash_local_iterator& __y)
+        {return !(__x == __y);}
+
+private:
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_local_iterator(__next_pointer __node, size_t __bucket,
+                          size_t __bucket_count, const void* __c) _NOEXCEPT
+        : __node_(__node),
+          __bucket_(__bucket),
+          __bucket_count_(__bucket_count)
+        {
+            __get_db()->__insert_ic(this, __c);
+            if (__node_ != nullptr)
+                __node_ = __node_->__next_;
+        }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_local_iterator(__next_pointer __node, size_t __bucket,
+                          size_t __bucket_count) _NOEXCEPT
+        : __node_(__node),
+          __bucket_(__bucket),
+          __bucket_count_(__bucket_count)
+        {
+            if (__node_ != nullptr)
+                __node_ = __node_->__next_;
+        }
+#endif
+    template <class, class, class, class> friend class __hash_table;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
+};
+
+template <class _ConstNodePtr>
+class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator
+{
+    typedef __hash_node_types<_ConstNodePtr> _NodeTypes;
+    typedef _ConstNodePtr                       __node_pointer;
+    typedef typename _NodeTypes::__next_pointer __next_pointer;
+
+    __next_pointer         __node_;
+    size_t                 __bucket_;
+    size_t                 __bucket_count_;
+
+    typedef pointer_traits<__node_pointer>          __pointer_traits;
+    typedef typename __pointer_traits::element_type __node;
+    typedef typename remove_const<__node>::type     __non_const_node;
+    typedef typename __rebind_pointer<__node_pointer, __non_const_node>::type
+        __non_const_node_pointer;
+public:
+    typedef __hash_local_iterator<__non_const_node_pointer>
+                                                    __non_const_iterator;
+
+    typedef forward_iterator_tag                                 iterator_category;
+    typedef typename _NodeTypes::__node_value_type               value_type;
+    typedef typename _NodeTypes::difference_type                 difference_type;
+    typedef const value_type&                                    reference;
+    typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
+
+
+    _LIBCPP_INLINE_VISIBILITY __hash_const_local_iterator() _NOEXCEPT : __node_(nullptr) {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_i(this);
+#endif
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_local_iterator(const __non_const_iterator& __x) _NOEXCEPT
+        : __node_(__x.__node_),
+          __bucket_(__x.__bucket_),
+          __bucket_count_(__x.__bucket_count_)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__iterator_copy(this, &__x);
+#endif
+    }
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_local_iterator(const __hash_const_local_iterator& __i)
+        : __node_(__i.__node_),
+          __bucket_(__i.__bucket_),
+          __bucket_count_(__i.__bucket_count_)
+    {
+        __get_db()->__iterator_copy(this, &__i);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~__hash_const_local_iterator()
+    {
+        __get_db()->__erase_i(this);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_local_iterator& operator=(const __hash_const_local_iterator& __i)
+    {
+        if (this != &__i)
+        {
+            __get_db()->__iterator_copy(this, &__i);
+            __node_ = __i.__node_;
+            __bucket_ = __i.__bucket_;
+            __bucket_count_ = __i.__bucket_count_;
+        }
+        return *this;
+    }
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {
+        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
+                           "Attempted to dereference a non-dereferenceable unordered container const_local_iterator");
+        return __node_->__upcast()->__value_;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {
+        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
+                           "Attempted to dereference a non-dereferenceable unordered container const_local_iterator");
+        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_local_iterator& operator++() {
+        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to increment a non-incrementable unordered container const_local_iterator");
+        __node_ = __node_->__next_;
+        if (__node_ != nullptr && __constrain_hash(__node_->__hash(), __bucket_count_) != __bucket_)
+            __node_ = nullptr;
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_local_iterator operator++(int)
+    {
+        __hash_const_local_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __hash_const_local_iterator& __x, const __hash_const_local_iterator& __y)
+    {
+        return __x.__node_ == __y.__node_;
+    }
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __hash_const_local_iterator& __x, const __hash_const_local_iterator& __y)
+        {return !(__x == __y);}
+
+private:
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_local_iterator(__next_pointer __node_ptr, size_t __bucket,
+                                size_t __bucket_count, const void* __c) _NOEXCEPT
+        : __node_(__node_ptr),
+          __bucket_(__bucket),
+          __bucket_count_(__bucket_count)
+        {
+            __get_db()->__insert_ic(this, __c);
+            if (__node_ != nullptr)
+                __node_ = __node_->__next_;
+        }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_const_local_iterator(__next_pointer __node_ptr, size_t __bucket,
+                                size_t __bucket_count) _NOEXCEPT
+        : __node_(__node_ptr),
+          __bucket_(__bucket),
+          __bucket_count_(__bucket_count)
+        {
+            if (__node_ != nullptr)
+                __node_ = __node_->__next_;
+        }
+#endif
+    template <class, class, class, class> friend class __hash_table;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
+};
+
+template <class _Alloc>
+class __bucket_list_deallocator
+{
+    typedef _Alloc                                          allocator_type;
+    typedef allocator_traits<allocator_type>                __alloc_traits;
+    typedef typename __alloc_traits::size_type              size_type;
+
+    __compressed_pair<size_type, allocator_type> __data_;
+public:
+    typedef typename __alloc_traits::pointer pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __bucket_list_deallocator()
+        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
+        : __data_(0, __default_init_tag()) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __bucket_list_deallocator(const allocator_type& __a, size_type __size)
+        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
+        : __data_(__size, __a) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __bucket_list_deallocator(__bucket_list_deallocator&& __x)
+        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
+        : __data_(_VSTD::move(__x.__data_))
+    {
+        __x.size() = 0;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type& size() _NOEXCEPT {return __data_.first();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type  size() const _NOEXCEPT {return __data_.first();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type& __alloc() _NOEXCEPT {return __data_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    const allocator_type& __alloc() const _NOEXCEPT {return __data_.second();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator()(pointer __p) _NOEXCEPT
+    {
+        __alloc_traits::deallocate(__alloc(), __p, size());
+    }
+};
+
+template <class _Alloc> class __hash_map_node_destructor;
+
+template <class _Alloc>
+class __hash_node_destructor
+{
+    typedef _Alloc                                          allocator_type;
+    typedef allocator_traits<allocator_type>                __alloc_traits;
+
+public:
+    typedef typename __alloc_traits::pointer                pointer;
+private:
+    typedef __hash_node_types<pointer> _NodeTypes;
+
+    allocator_type& __na_;
+
+public:
+    bool __value_constructed;
+
+    __hash_node_destructor(__hash_node_destructor const&) = default;
+    __hash_node_destructor& operator=(const __hash_node_destructor&) = delete;
+
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __hash_node_destructor(allocator_type& __na,
+                                    bool __constructed = false) _NOEXCEPT
+        : __na_(__na),
+          __value_constructed(__constructed)
+        {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator()(pointer __p) _NOEXCEPT
+    {
+        if (__value_constructed)
+            __alloc_traits::destroy(__na_, _NodeTypes::__get_ptr(__p->__value_));
+        if (__p)
+            __alloc_traits::deallocate(__na_, __p, 1);
+    }
+
+    template <class> friend class __hash_map_node_destructor;
+};
+
+#if _LIBCPP_STD_VER > 14
+template <class _NodeType, class _Alloc>
+struct __generic_container_node_destructor;
+
+template <class _Tp, class _VoidPtr, class _Alloc>
+struct __generic_container_node_destructor<__hash_node<_Tp, _VoidPtr>, _Alloc>
+    : __hash_node_destructor<_Alloc>
+{
+    using __hash_node_destructor<_Alloc>::__hash_node_destructor;
+};
+#endif
+
+template <class _Key, class _Hash, class _Equal>
+struct __enforce_unordered_container_requirements {
+#ifndef _LIBCPP_CXX03_LANG
+    static_assert(__check_hash_requirements<_Key, _Hash>::value,
+    "the specified hash does not meet the Hash requirements");
+    static_assert(is_copy_constructible<_Equal>::value,
+    "the specified comparator is required to be copy constructible");
+#endif
+    typedef int type;
+};
+
+template <class _Key, class _Hash, class _Equal>
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_DIAGNOSE_WARNING(!__invokable<_Equal const&, _Key const&, _Key const&>::value,
+    "the specified comparator type does not provide a viable const call operator")
+    _LIBCPP_DIAGNOSE_WARNING(!__invokable<_Hash const&, _Key const&>::value,
+    "the specified hash functor does not provide a viable const call operator")
+#endif
+typename __enforce_unordered_container_requirements<_Key, _Hash, _Equal>::type
+__diagnose_unordered_container_requirements(int);
+
+// This dummy overload is used so that the compiler won't emit a spurious
+// "no matching function for call to __diagnose_unordered_xxx" diagnostic
+// when the overload above causes a hard error.
+template <class _Key, class _Hash, class _Equal>
+int __diagnose_unordered_container_requirements(void*);
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+class __hash_table
+{
+public:
+    typedef _Tp    value_type;
+    typedef _Hash  hasher;
+    typedef _Equal key_equal;
+    typedef _Alloc allocator_type;
+
+private:
+    typedef allocator_traits<allocator_type> __alloc_traits;
+    typedef typename
+      __make_hash_node_types<value_type, typename __alloc_traits::void_pointer>::type
+                                                                     _NodeTypes;
+public:
+
+    typedef typename _NodeTypes::__node_value_type           __node_value_type;
+    typedef typename _NodeTypes::__container_value_type      __container_value_type;
+    typedef typename _NodeTypes::key_type                    key_type;
+    typedef value_type&                              reference;
+    typedef const value_type&                        const_reference;
+    typedef typename __alloc_traits::pointer         pointer;
+    typedef typename __alloc_traits::const_pointer   const_pointer;
+#ifndef _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
+    typedef typename __alloc_traits::size_type       size_type;
+#else
+    typedef typename _NodeTypes::size_type           size_type;
+#endif
+    typedef typename _NodeTypes::difference_type     difference_type;
+public:
+    // Create __node
+
+    typedef typename _NodeTypes::__node_type __node;
+    typedef typename __rebind_alloc_helper<__alloc_traits, __node>::type __node_allocator;
+    typedef allocator_traits<__node_allocator>       __node_traits;
+    typedef typename _NodeTypes::__void_pointer      __void_pointer;
+    typedef typename _NodeTypes::__node_pointer      __node_pointer;
+    typedef typename _NodeTypes::__node_pointer      __node_const_pointer;
+    typedef typename _NodeTypes::__node_base_type    __first_node;
+    typedef typename _NodeTypes::__node_base_pointer __node_base_pointer;
+    typedef typename _NodeTypes::__next_pointer      __next_pointer;
+
+private:
+    // check for sane allocator pointer rebinding semantics. Rebinding the
+    // allocator for a new pointer type should be exactly the same as rebinding
+    // the pointer using 'pointer_traits'.
+    static_assert((is_same<__node_pointer, typename __node_traits::pointer>::value),
+                  "Allocator does not rebind pointers in a sane manner.");
+    typedef typename __rebind_alloc_helper<__node_traits, __first_node>::type
+        __node_base_allocator;
+    typedef allocator_traits<__node_base_allocator> __node_base_traits;
+    static_assert((is_same<__node_base_pointer, typename __node_base_traits::pointer>::value),
+                 "Allocator does not rebind pointers in a sane manner.");
+
+private:
+
+    typedef typename __rebind_alloc_helper<__node_traits, __next_pointer>::type __pointer_allocator;
+    typedef __bucket_list_deallocator<__pointer_allocator> __bucket_list_deleter;
+    typedef unique_ptr<__next_pointer[], __bucket_list_deleter> __bucket_list;
+    typedef allocator_traits<__pointer_allocator>          __pointer_alloc_traits;
+    typedef typename __bucket_list_deleter::pointer       __node_pointer_pointer;
+
+    // --- Member data begin ---
+    __bucket_list                                         __bucket_list_;
+    __compressed_pair<__first_node, __node_allocator>     __p1_;
+    __compressed_pair<size_type, hasher>                  __p2_;
+    __compressed_pair<float, key_equal>                   __p3_;
+    // --- Member data end ---
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type& size() _NOEXCEPT {return __p2_.first();}
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    size_type  size() const _NOEXCEPT {return __p2_.first();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    hasher& hash_function() _NOEXCEPT {return __p2_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    const hasher& hash_function() const _NOEXCEPT {return __p2_.second();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    float& max_load_factor() _NOEXCEPT {return __p3_.first();}
+    _LIBCPP_INLINE_VISIBILITY
+    float  max_load_factor() const _NOEXCEPT {return __p3_.first();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    key_equal& key_eq() _NOEXCEPT {return __p3_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    const key_equal& key_eq() const _NOEXCEPT {return __p3_.second();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __node_allocator& __node_alloc() _NOEXCEPT {return __p1_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    const __node_allocator& __node_alloc() const _NOEXCEPT
+        {return __p1_.second();}
+
+public:
+    typedef __hash_iterator<__node_pointer>                   iterator;
+    typedef __hash_const_iterator<__node_pointer>             const_iterator;
+    typedef __hash_local_iterator<__node_pointer>             local_iterator;
+    typedef __hash_const_local_iterator<__node_pointer>       const_local_iterator;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_table()
+        _NOEXCEPT_(
+            is_nothrow_default_constructible<__bucket_list>::value &&
+            is_nothrow_default_constructible<__first_node>::value &&
+            is_nothrow_default_constructible<__node_allocator>::value &&
+            is_nothrow_default_constructible<hasher>::value &&
+            is_nothrow_default_constructible<key_equal>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_table(const hasher& __hf, const key_equal& __eql);
+    __hash_table(const hasher& __hf, const key_equal& __eql,
+                 const allocator_type& __a);
+    explicit __hash_table(const allocator_type& __a);
+    __hash_table(const __hash_table& __u);
+    __hash_table(const __hash_table& __u, const allocator_type& __a);
+    __hash_table(__hash_table&& __u)
+        _NOEXCEPT_(
+            is_nothrow_move_constructible<__bucket_list>::value &&
+            is_nothrow_move_constructible<__first_node>::value &&
+            is_nothrow_move_constructible<__node_allocator>::value &&
+            is_nothrow_move_constructible<hasher>::value &&
+            is_nothrow_move_constructible<key_equal>::value);
+    __hash_table(__hash_table&& __u, const allocator_type& __a);
+    ~__hash_table();
+
+    __hash_table& operator=(const __hash_table& __u);
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_table& operator=(__hash_table&& __u)
+        _NOEXCEPT_(
+            __node_traits::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<__node_allocator>::value &&
+            is_nothrow_move_assignable<hasher>::value &&
+            is_nothrow_move_assignable<key_equal>::value);
+    template <class _InputIterator>
+        void __assign_unique(_InputIterator __first, _InputIterator __last);
+    template <class _InputIterator>
+        void __assign_multi(_InputIterator __first, _InputIterator __last);
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT
+    {
+        return _VSTD::min<size_type>(
+            __node_traits::max_size(__node_alloc()),
+            numeric_limits<difference_type >::max()
+        );
+    }
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    __next_pointer __node_insert_multi_prepare(size_t __cp_hash,
+                                               value_type& __cp_val);
+    _LIBCPP_INLINE_VISIBILITY
+    void __node_insert_multi_perform(__node_pointer __cp,
+                                     __next_pointer __pn) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __next_pointer __node_insert_unique_prepare(size_t __nd_hash,
+                                                value_type& __nd_val);
+    _LIBCPP_INLINE_VISIBILITY
+    void __node_insert_unique_perform(__node_pointer __ptr) _NOEXCEPT;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> __node_insert_unique(__node_pointer __nd);
+    _LIBCPP_INLINE_VISIBILITY
+    iterator             __node_insert_multi(__node_pointer __nd);
+    _LIBCPP_INLINE_VISIBILITY
+    iterator             __node_insert_multi(const_iterator __p,
+                                             __node_pointer __nd);
+
+    template <class _Key, class ..._Args>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> __emplace_unique_key_args(_Key const& __k, _Args&&... __args);
+
+    template <class... _Args>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> __emplace_unique_impl(_Args&&... __args);
+
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> __emplace_unique(_Pp&& __x) {
+      return __emplace_unique_extract_key(_VSTD::forward<_Pp>(__x),
+                                          __can_extract_key<_Pp, key_type>());
+    }
+
+    template <class _First, class _Second>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<
+        __can_extract_map_key<_First, key_type, __container_value_type>::value,
+        pair<iterator, bool>
+    >::type __emplace_unique(_First&& __f, _Second&& __s) {
+        return __emplace_unique_key_args(__f, _VSTD::forward<_First>(__f),
+                                              _VSTD::forward<_Second>(__s));
+    }
+
+    template <class... _Args>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> __emplace_unique(_Args&&... __args) {
+      return __emplace_unique_impl(_VSTD::forward<_Args>(__args)...);
+    }
+
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool>
+    __emplace_unique_extract_key(_Pp&& __x, __extract_key_fail_tag) {
+      return __emplace_unique_impl(_VSTD::forward<_Pp>(__x));
+    }
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool>
+    __emplace_unique_extract_key(_Pp&& __x, __extract_key_self_tag) {
+      return __emplace_unique_key_args(__x, _VSTD::forward<_Pp>(__x));
+    }
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool>
+    __emplace_unique_extract_key(_Pp&& __x, __extract_key_first_tag) {
+      return __emplace_unique_key_args(__x.first, _VSTD::forward<_Pp>(__x));
+    }
+
+    template <class... _Args>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __emplace_multi(_Args&&... __args);
+    template <class... _Args>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __emplace_hint_multi(const_iterator __p, _Args&&... __args);
+
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool>
+    __insert_unique(__container_value_type&& __x) {
+      return __emplace_unique_key_args(_NodeTypes::__get_key(__x), _VSTD::move(__x));
+    }
+
+    template <class _Pp, class = typename enable_if<
+            !__is_same_uncvref<_Pp, __container_value_type>::value
+        >::type>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> __insert_unique(_Pp&& __x) {
+      return __emplace_unique(_VSTD::forward<_Pp>(__x));
+    }
+
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __insert_multi(_Pp&& __x) {
+      return __emplace_multi(_VSTD::forward<_Pp>(__x));
+    }
+
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __insert_multi(const_iterator __p, _Pp&& __x) {
+        return __emplace_hint_multi(__p, _VSTD::forward<_Pp>(__x));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> __insert_unique(const __container_value_type& __x) {
+        return __emplace_unique_key_args(_NodeTypes::__get_key(__x), __x);
+    }
+
+#if _LIBCPP_STD_VER > 14
+    template <class _NodeHandle, class _InsertReturnType>
+    _LIBCPP_INLINE_VISIBILITY
+    _InsertReturnType __node_handle_insert_unique(_NodeHandle&& __nh);
+    template <class _NodeHandle>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __node_handle_insert_unique(const_iterator __hint,
+                                         _NodeHandle&& __nh);
+    template <class _Table>
+    _LIBCPP_INLINE_VISIBILITY
+    void __node_handle_merge_unique(_Table& __source);
+
+    template <class _NodeHandle>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __node_handle_insert_multi(_NodeHandle&& __nh);
+    template <class _NodeHandle>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __node_handle_insert_multi(const_iterator __hint, _NodeHandle&& __nh);
+    template <class _Table>
+    _LIBCPP_INLINE_VISIBILITY
+    void __node_handle_merge_multi(_Table& __source);
+
+    template <class _NodeHandle>
+    _LIBCPP_INLINE_VISIBILITY
+    _NodeHandle __node_handle_extract(key_type const& __key);
+    template <class _NodeHandle>
+    _LIBCPP_INLINE_VISIBILITY
+    _NodeHandle __node_handle_extract(const_iterator __it);
+#endif
+
+    void clear() _NOEXCEPT;
+    void rehash(size_type __n);
+    _LIBCPP_INLINE_VISIBILITY void reserve(size_type __n)
+        {rehash(static_cast<size_type>(ceil(__n / max_load_factor())));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket_count() const _NOEXCEPT
+    {
+        return __bucket_list_.get_deleter().size();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       begin() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       end() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end() const _NOEXCEPT;
+
+    template <class _Key>
+        _LIBCPP_INLINE_VISIBILITY
+        size_type bucket(const _Key& __k) const
+        {
+            _LIBCPP_ASSERT(bucket_count() > 0,
+                "unordered container::bucket(key) called when bucket_count() == 0");
+            return __constrain_hash(hash_function()(__k), bucket_count());
+        }
+
+    template <class _Key>
+        iterator       find(const _Key& __x);
+    template <class _Key>
+        const_iterator find(const _Key& __x) const;
+
+    typedef __hash_node_destructor<__node_allocator> _Dp;
+    typedef unique_ptr<__node, _Dp> __node_holder;
+
+    iterator erase(const_iterator __p);
+    iterator erase(const_iterator __first, const_iterator __last);
+    template <class _Key>
+        size_type __erase_unique(const _Key& __k);
+    template <class _Key>
+        size_type __erase_multi(const _Key& __k);
+    __node_holder remove(const_iterator __p) _NOEXCEPT;
+
+    template <class _Key>
+        _LIBCPP_INLINE_VISIBILITY
+        size_type __count_unique(const _Key& __k) const;
+    template <class _Key>
+        size_type __count_multi(const _Key& __k) const;
+
+    template <class _Key>
+        pair<iterator, iterator>
+        __equal_range_unique(const _Key& __k);
+    template <class _Key>
+        pair<const_iterator, const_iterator>
+        __equal_range_unique(const _Key& __k) const;
+
+    template <class _Key>
+        pair<iterator, iterator>
+        __equal_range_multi(const _Key& __k);
+    template <class _Key>
+        pair<const_iterator, const_iterator>
+        __equal_range_multi(const _Key& __k) const;
+
+    void swap(__hash_table& __u)
+#if _LIBCPP_STD_VER <= 11
+        _NOEXCEPT_(
+            __is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value
+            && (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value
+                  || __is_nothrow_swappable<__pointer_allocator>::value)
+            && (!__node_traits::propagate_on_container_swap::value
+                  || __is_nothrow_swappable<__node_allocator>::value)
+            );
+#else
+     _NOEXCEPT_(__is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value);
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_bucket_count() const _NOEXCEPT
+        {return max_size(); }
+    size_type bucket_size(size_type __n) const;
+    _LIBCPP_INLINE_VISIBILITY float load_factor() const _NOEXCEPT
+    {
+        size_type __bc = bucket_count();
+        return __bc != 0 ? (float)size() / __bc : 0.f;
+    }
+    _LIBCPP_INLINE_VISIBILITY void max_load_factor(float __mlf) _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__mlf > 0,
+            "unordered container::max_load_factor(lf) called with lf <= 0");
+        max_load_factor() = _VSTD::max(__mlf, load_factor());
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    local_iterator
+    begin(size_type __n)
+    {
+        _LIBCPP_ASSERT(__n < bucket_count(),
+            "unordered container::begin(n) called with n >= bucket_count()");
+#if _LIBCPP_DEBUG_LEVEL == 2
+        return local_iterator(__bucket_list_[__n], __n, bucket_count(), this);
+#else
+        return local_iterator(__bucket_list_[__n], __n, bucket_count());
+#endif
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    local_iterator
+    end(size_type __n)
+    {
+        _LIBCPP_ASSERT(__n < bucket_count(),
+            "unordered container::end(n) called with n >= bucket_count()");
+#if _LIBCPP_DEBUG_LEVEL == 2
+        return local_iterator(nullptr, __n, bucket_count(), this);
+#else
+        return local_iterator(nullptr, __n, bucket_count());
+#endif
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator
+    cbegin(size_type __n) const
+    {
+        _LIBCPP_ASSERT(__n < bucket_count(),
+            "unordered container::cbegin(n) called with n >= bucket_count()");
+#if _LIBCPP_DEBUG_LEVEL == 2
+        return const_local_iterator(__bucket_list_[__n], __n, bucket_count(), this);
+#else
+        return const_local_iterator(__bucket_list_[__n], __n, bucket_count());
+#endif
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator
+    cend(size_type __n) const
+    {
+        _LIBCPP_ASSERT(__n < bucket_count(),
+            "unordered container::cend(n) called with n >= bucket_count()");
+#if _LIBCPP_DEBUG_LEVEL == 2
+        return const_local_iterator(nullptr, __n, bucket_count(), this);
+#else
+        return const_local_iterator(nullptr, __n, bucket_count());
+#endif
+    }
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+    bool __dereferenceable(const const_iterator* __i) const;
+    bool __decrementable(const const_iterator* __i) const;
+    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
+    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+private:
+    void __rehash(size_type __n);
+
+    template <class ..._Args>
+    __node_holder __construct_node(_Args&& ...__args);
+
+    template <class _First, class ..._Rest>
+    __node_holder __construct_node_hash(size_t __hash, _First&& __f, _Rest&&... __rest);
+
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __hash_table& __u)
+        {__copy_assign_alloc(__u, integral_constant<bool,
+             __node_traits::propagate_on_container_copy_assignment::value>());}
+    void __copy_assign_alloc(const __hash_table& __u, true_type);
+    _LIBCPP_INLINE_VISIBILITY
+        void __copy_assign_alloc(const __hash_table&, false_type) {}
+
+    void __move_assign(__hash_table& __u, false_type);
+    void __move_assign(__hash_table& __u, true_type)
+        _NOEXCEPT_(
+            is_nothrow_move_assignable<__node_allocator>::value &&
+            is_nothrow_move_assignable<hasher>::value &&
+            is_nothrow_move_assignable<key_equal>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__hash_table& __u)
+        _NOEXCEPT_(
+            !__node_traits::propagate_on_container_move_assignment::value ||
+            (is_nothrow_move_assignable<__pointer_allocator>::value &&
+             is_nothrow_move_assignable<__node_allocator>::value))
+        {__move_assign_alloc(__u, integral_constant<bool,
+             __node_traits::propagate_on_container_move_assignment::value>());}
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__hash_table& __u, true_type)
+        _NOEXCEPT_(
+            is_nothrow_move_assignable<__pointer_allocator>::value &&
+            is_nothrow_move_assignable<__node_allocator>::value)
+    {
+        __bucket_list_.get_deleter().__alloc() =
+                _VSTD::move(__u.__bucket_list_.get_deleter().__alloc());
+        __node_alloc() = _VSTD::move(__u.__node_alloc());
+    }
+    _LIBCPP_INLINE_VISIBILITY
+        void __move_assign_alloc(__hash_table&, false_type) _NOEXCEPT {}
+
+    void __deallocate_node(__next_pointer __np) _NOEXCEPT;
+    __next_pointer __detach() _NOEXCEPT;
+
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
+};
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+inline
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table()
+    _NOEXCEPT_(
+        is_nothrow_default_constructible<__bucket_list>::value &&
+        is_nothrow_default_constructible<__first_node>::value &&
+        is_nothrow_default_constructible<__node_allocator>::value &&
+        is_nothrow_default_constructible<hasher>::value &&
+        is_nothrow_default_constructible<key_equal>::value)
+    : __p2_(0, __default_init_tag()),
+      __p3_(1.0f, __default_init_tag())
+{
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+inline
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const hasher& __hf,
+                                                       const key_equal& __eql)
+    : __bucket_list_(nullptr, __bucket_list_deleter()),
+      __p1_(),
+      __p2_(0, __hf),
+      __p3_(1.0f, __eql)
+{
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const hasher& __hf,
+                                                       const key_equal& __eql,
+                                                       const allocator_type& __a)
+    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
+      __p1_(__default_init_tag(), __node_allocator(__a)),
+      __p2_(0, __hf),
+      __p3_(1.0f, __eql)
+{
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const allocator_type& __a)
+    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
+      __p1_(__default_init_tag(), __node_allocator(__a)),
+      __p2_(0, __default_init_tag()),
+      __p3_(1.0f, __default_init_tag())
+{
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u)
+    : __bucket_list_(nullptr,
+          __bucket_list_deleter(allocator_traits<__pointer_allocator>::
+              select_on_container_copy_construction(
+                  __u.__bucket_list_.get_deleter().__alloc()), 0)),
+      __p1_(__default_init_tag(), allocator_traits<__node_allocator>::
+          select_on_container_copy_construction(__u.__node_alloc())),
+      __p2_(0, __u.hash_function()),
+      __p3_(__u.__p3_)
+{
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u,
+                                                       const allocator_type& __a)
+    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
+      __p1_(__default_init_tag(), __node_allocator(__a)),
+      __p2_(0, __u.hash_function()),
+      __p3_(__u.__p3_)
+{
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u)
+        _NOEXCEPT_(
+            is_nothrow_move_constructible<__bucket_list>::value &&
+            is_nothrow_move_constructible<__first_node>::value &&
+            is_nothrow_move_constructible<__node_allocator>::value &&
+            is_nothrow_move_constructible<hasher>::value &&
+            is_nothrow_move_constructible<key_equal>::value)
+    : __bucket_list_(_VSTD::move(__u.__bucket_list_)),
+      __p1_(_VSTD::move(__u.__p1_)),
+      __p2_(_VSTD::move(__u.__p2_)),
+      __p3_(_VSTD::move(__u.__p3_))
+{
+    if (size() > 0)
+    {
+        __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
+            __p1_.first().__ptr();
+        __u.__p1_.first().__next_ = nullptr;
+        __u.size() = 0;
+    }
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u,
+                                                       const allocator_type& __a)
+    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
+      __p1_(__default_init_tag(), __node_allocator(__a)),
+      __p2_(0, _VSTD::move(__u.hash_function())),
+      __p3_(_VSTD::move(__u.__p3_))
+{
+    if (__a == allocator_type(__u.__node_alloc()))
+    {
+        __bucket_list_.reset(__u.__bucket_list_.release());
+        __bucket_list_.get_deleter().size() = __u.__bucket_list_.get_deleter().size();
+        __u.__bucket_list_.get_deleter().size() = 0;
+        if (__u.size() > 0)
+        {
+            __p1_.first().__next_ = __u.__p1_.first().__next_;
+            __u.__p1_.first().__next_ = nullptr;
+            __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
+                __p1_.first().__ptr();
+            size() = __u.size();
+            __u.size() = 0;
+        }
+    }
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::~__hash_table()
+{
+#if defined(_LIBCPP_CXX03_LANG)
+    static_assert((is_copy_constructible<key_equal>::value),
+                 "Predicate must be copy-constructible.");
+    static_assert((is_copy_constructible<hasher>::value),
+                 "Hasher must be copy-constructible.");
+#endif
+
+    __deallocate_node(__p1_.first().__next_);
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__erase_c(this);
+#endif
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__copy_assign_alloc(
+        const __hash_table& __u, true_type)
+{
+    if (__node_alloc() != __u.__node_alloc())
+    {
+        clear();
+        __bucket_list_.reset();
+        __bucket_list_.get_deleter().size() = 0;
+    }
+    __bucket_list_.get_deleter().__alloc() = __u.__bucket_list_.get_deleter().__alloc();
+    __node_alloc() = __u.__node_alloc();
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>&
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(const __hash_table& __u)
+{
+    if (this != _VSTD::addressof(__u))
+    {
+        __copy_assign_alloc(__u);
+        hash_function() = __u.hash_function();
+        key_eq() = __u.key_eq();
+        max_load_factor() = __u.max_load_factor();
+        __assign_multi(__u.begin(), __u.end());
+    }
+    return *this;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__deallocate_node(__next_pointer __np)
+    _NOEXCEPT
+{
+    __node_allocator& __na = __node_alloc();
+    while (__np != nullptr)
+    {
+        __next_pointer __next = __np->__next_;
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __c_node* __c = __get_db()->__find_c_and_lock(this);
+        for (__i_node** __p = __c->end_; __p != __c->beg_; )
+        {
+            --__p;
+            iterator* __i = static_cast<iterator*>((*__p)->__i_);
+            if (__i->__node_ == __np)
+            {
+                (*__p)->__c_ = nullptr;
+                if (--__c->end_ != __p)
+                    _VSTD::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
+            }
+        }
+        __get_db()->unlock();
+#endif
+        __node_pointer __real_np = __np->__upcast();
+        __node_traits::destroy(__na, _NodeTypes::__get_ptr(__real_np->__value_));
+        __node_traits::deallocate(__na, __real_np, 1);
+        __np = __next;
+    }
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__detach() _NOEXCEPT
+{
+    size_type __bc = bucket_count();
+    for (size_type __i = 0; __i < __bc; ++__i)
+        __bucket_list_[__i] = nullptr;
+    size() = 0;
+    __next_pointer __cache = __p1_.first().__next_;
+    __p1_.first().__next_ = nullptr;
+    return __cache;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(
+        __hash_table& __u, true_type)
+    _NOEXCEPT_(
+        is_nothrow_move_assignable<__node_allocator>::value &&
+        is_nothrow_move_assignable<hasher>::value &&
+        is_nothrow_move_assignable<key_equal>::value)
+{
+    clear();
+    __bucket_list_.reset(__u.__bucket_list_.release());
+    __bucket_list_.get_deleter().size() = __u.__bucket_list_.get_deleter().size();
+    __u.__bucket_list_.get_deleter().size() = 0;
+    __move_assign_alloc(__u);
+    size() = __u.size();
+    hash_function() = _VSTD::move(__u.hash_function());
+    max_load_factor() = __u.max_load_factor();
+    key_eq() = _VSTD::move(__u.key_eq());
+    __p1_.first().__next_ = __u.__p1_.first().__next_;
+    if (size() > 0)
+    {
+        __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
+            __p1_.first().__ptr();
+        __u.__p1_.first().__next_ = nullptr;
+        __u.size() = 0;
+    }
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->swap(this, &__u);
+#endif
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(
+        __hash_table& __u, false_type)
+{
+    if (__node_alloc() == __u.__node_alloc())
+        __move_assign(__u, true_type());
+    else
+    {
+        hash_function() = _VSTD::move(__u.hash_function());
+        key_eq() = _VSTD::move(__u.key_eq());
+        max_load_factor() = __u.max_load_factor();
+        if (bucket_count() != 0)
+        {
+            __next_pointer __cache = __detach();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+            try
+            {
+#endif // _LIBCPP_NO_EXCEPTIONS
+                const_iterator __i = __u.begin();
+                while (__cache != nullptr && __u.size() != 0)
+                {
+                    __cache->__upcast()->__value_ =
+                        _VSTD::move(__u.remove(__i++)->__value_);
+                    __next_pointer __next = __cache->__next_;
+                    __node_insert_multi(__cache->__upcast());
+                    __cache = __next;
+                }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+            }
+            catch (...)
+            {
+                __deallocate_node(__cache);
+                throw;
+            }
+#endif // _LIBCPP_NO_EXCEPTIONS
+            __deallocate_node(__cache);
+        }
+        const_iterator __i = __u.begin();
+        while (__u.size() != 0)
+        {
+            __node_holder __h = __construct_node(_NodeTypes::__move(__u.remove(__i++)->__value_));
+            __node_insert_multi(__h.get());
+            __h.release();
+        }
+    }
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+inline
+__hash_table<_Tp, _Hash, _Equal, _Alloc>&
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(__hash_table&& __u)
+    _NOEXCEPT_(
+        __node_traits::propagate_on_container_move_assignment::value &&
+        is_nothrow_move_assignable<__node_allocator>::value &&
+        is_nothrow_move_assignable<hasher>::value &&
+        is_nothrow_move_assignable<key_equal>::value)
+{
+    __move_assign(__u, integral_constant<bool,
+                  __node_traits::propagate_on_container_move_assignment::value>());
+    return *this;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _InputIterator>
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_unique(_InputIterator __first,
+                                                          _InputIterator __last)
+{
+    typedef iterator_traits<_InputIterator> _ITraits;
+    typedef typename _ITraits::value_type _ItValueType;
+    static_assert((is_same<_ItValueType, __container_value_type>::value),
+                  "__assign_unique may only be called with the containers value type");
+
+    if (bucket_count() != 0)
+    {
+        __next_pointer __cache = __detach();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (; __cache != nullptr && __first != __last; ++__first)
+            {
+                __cache->__upcast()->__value_ = *__first;
+                __next_pointer __next = __cache->__next_;
+                __node_insert_unique(__cache->__upcast());
+                __cache = __next;
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __deallocate_node(__cache);
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __deallocate_node(__cache);
+    }
+    for (; __first != __last; ++__first)
+        __insert_unique(*__first);
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _InputIterator>
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_multi(_InputIterator __first,
+                                                         _InputIterator __last)
+{
+    typedef iterator_traits<_InputIterator> _ITraits;
+    typedef typename _ITraits::value_type _ItValueType;
+    static_assert((is_same<_ItValueType, __container_value_type>::value ||
+                  is_same<_ItValueType, __node_value_type>::value),
+                  "__assign_multi may only be called with the containers value type"
+                  " or the nodes value type");
+    if (bucket_count() != 0)
+    {
+        __next_pointer __cache = __detach();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (; __cache != nullptr && __first != __last; ++__first)
+            {
+                __cache->__upcast()->__value_ = *__first;
+                __next_pointer __next = __cache->__next_;
+                __node_insert_multi(__cache->__upcast());
+                __cache = __next;
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __deallocate_node(__cache);
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __deallocate_node(__cache);
+    }
+    for (; __first != __last; ++__first)
+        __insert_multi(_NodeTypes::__get_value(*__first));
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+inline
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() _NOEXCEPT
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(__p1_.first().__next_, this);
+#else
+    return iterator(__p1_.first().__next_);
+#endif
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+inline
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::end() _NOEXCEPT
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(nullptr, this);
+#else
+    return iterator(nullptr);
+#endif
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+inline
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() const _NOEXCEPT
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return const_iterator(__p1_.first().__next_, this);
+#else
+    return const_iterator(__p1_.first().__next_);
+#endif
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+inline
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::end() const _NOEXCEPT
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return const_iterator(nullptr, this);
+#else
+    return const_iterator(nullptr);
+#endif
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::clear() _NOEXCEPT
+{
+    if (size() > 0)
+    {
+        __deallocate_node(__p1_.first().__next_);
+        __p1_.first().__next_ = nullptr;
+        size_type __bc = bucket_count();
+        for (size_type __i = 0; __i < __bc; ++__i)
+            __bucket_list_[__i] = nullptr;
+        size() = 0;
+    }
+}
+
+
+// Prepare the container for an insertion of the value __value with the hash
+// __hash. This does a lookup into the container to see if __value is already
+// present, and performs a rehash if necessary. Returns a pointer to the
+// existing element if it exists, otherwise nullptr.
+//
+// Note that this function does forward exceptions if key_eq() throws, and never
+// mutates __value or actually inserts into the map.
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+_LIBCPP_INLINE_VISIBILITY
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique_prepare(
+    size_t __hash, value_type& __value)
+{
+    size_type __bc = bucket_count();
+
+    if (__bc != 0)
+    {
+        size_t __chash = __constrain_hash(__hash, __bc);
+        __next_pointer __ndptr = __bucket_list_[__chash];
+        if (__ndptr != nullptr)
+        {
+            for (__ndptr = __ndptr->__next_; __ndptr != nullptr &&
+                                             __constrain_hash(__ndptr->__hash(), __bc) == __chash;
+                                                     __ndptr = __ndptr->__next_)
+            {
+                if (key_eq()(__ndptr->__upcast()->__value_, __value))
+                    return __ndptr;
+            }
+        }
+    }
+    if (size()+1 > __bc * max_load_factor() || __bc == 0)
+    {
+        rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
+                                     size_type(ceil(float(size() + 1) / max_load_factor()))));
+    }
+    return nullptr;
+}
+
+// Insert the node __nd into the container by pushing it into the right bucket,
+// and updating size(). Assumes that __nd->__hash is up-to-date, and that
+// rehashing has already occurred and that no element with the same key exists
+// in the map.
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+_LIBCPP_INLINE_VISIBILITY
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique_perform(
+    __node_pointer __nd) _NOEXCEPT
+{
+    size_type __bc = bucket_count();
+    size_t __chash = __constrain_hash(__nd->__hash(), __bc);
+    // insert_after __bucket_list_[__chash], or __first_node if bucket is null
+    __next_pointer __pn = __bucket_list_[__chash];
+    if (__pn == nullptr)
+    {
+        __pn =__p1_.first().__ptr();
+        __nd->__next_ = __pn->__next_;
+        __pn->__next_ = __nd->__ptr();
+        // fix up __bucket_list_
+        __bucket_list_[__chash] = __pn;
+        if (__nd->__next_ != nullptr)
+            __bucket_list_[__constrain_hash(__nd->__next_->__hash(), __bc)] = __nd->__ptr();
+    }
+    else
+    {
+        __nd->__next_ = __pn->__next_;
+        __pn->__next_ = __nd->__ptr();
+    }
+    ++size();
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique(__node_pointer __nd)
+{
+    __nd->__hash_ = hash_function()(__nd->__value_);
+    __next_pointer __existing_node =
+        __node_insert_unique_prepare(__nd->__hash(), __nd->__value_);
+
+    // Insert the node, unless it already exists in the container.
+    bool __inserted = false;
+    if (__existing_node == nullptr)
+    {
+        __node_insert_unique_perform(__nd);
+        __existing_node = __nd->__ptr();
+        __inserted = true;
+    }
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return pair<iterator, bool>(iterator(__existing_node, this), __inserted);
+#else
+    return pair<iterator, bool>(iterator(__existing_node), __inserted);
+#endif
+}
+
+// Prepare the container for an insertion of the value __cp_val with the hash
+// __cp_hash. This does a lookup into the container to see if __cp_value is
+// already present, and performs a rehash if necessary. Returns a pointer to the
+// last occurrence of __cp_val in the map.
+//
+// Note that this function does forward exceptions if key_eq() throws, and never
+// mutates __value or actually inserts into the map.
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi_prepare(
+    size_t __cp_hash, value_type& __cp_val)
+{
+    size_type __bc = bucket_count();
+    if (size()+1 > __bc * max_load_factor() || __bc == 0)
+    {
+        rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
+                       size_type(ceil(float(size() + 1) / max_load_factor()))));
+        __bc = bucket_count();
+    }
+    size_t __chash = __constrain_hash(__cp_hash, __bc);
+    __next_pointer __pn = __bucket_list_[__chash];
+    if (__pn != nullptr)
+    {
+        for (bool __found = false; __pn->__next_ != nullptr &&
+                                   __constrain_hash(__pn->__next_->__hash(), __bc) == __chash;
+                                                           __pn = __pn->__next_)
+        {
+            //      __found    key_eq()     action
+            //      false       false       loop
+            //      true        true        loop
+            //      false       true        set __found to true
+            //      true        false       break
+            if (__found != (__pn->__next_->__hash() == __cp_hash &&
+                            key_eq()(__pn->__next_->__upcast()->__value_, __cp_val)))
+            {
+                if (!__found)
+                    __found = true;
+                else
+                    break;
+            }
+        }
+    }
+    return __pn;
+}
+
+// Insert the node __cp into the container after __pn (which is the last node in
+// the bucket that compares equal to __cp). Rehashing, and checking for
+// uniqueness has already been performed (in __node_insert_multi_prepare), so
+// all we need to do is update the bucket and size(). Assumes that __cp->__hash
+// is up-to-date.
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi_perform(
+    __node_pointer __cp, __next_pointer __pn) _NOEXCEPT
+{
+    size_type __bc = bucket_count();
+    size_t __chash = __constrain_hash(__cp->__hash_, __bc);
+    if (__pn == nullptr)
+    {
+        __pn =__p1_.first().__ptr();
+        __cp->__next_ = __pn->__next_;
+        __pn->__next_ = __cp->__ptr();
+        // fix up __bucket_list_
+        __bucket_list_[__chash] = __pn;
+        if (__cp->__next_ != nullptr)
+            __bucket_list_[__constrain_hash(__cp->__next_->__hash(), __bc)]
+                = __cp->__ptr();
+    }
+    else
+    {
+        __cp->__next_ = __pn->__next_;
+        __pn->__next_ = __cp->__ptr();
+        if (__cp->__next_ != nullptr)
+        {
+            size_t __nhash = __constrain_hash(__cp->__next_->__hash(), __bc);
+            if (__nhash != __chash)
+                __bucket_list_[__nhash] = __cp->__ptr();
+        }
+    }
+    ++size();
+}
+
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(__node_pointer __cp)
+{
+    __cp->__hash_ = hash_function()(__cp->__value_);
+    __next_pointer __pn = __node_insert_multi_prepare(__cp->__hash(), __cp->__value_);
+    __node_insert_multi_perform(__cp, __pn);
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(__cp->__ptr(), this);
+#else
+    return iterator(__cp->__ptr());
+#endif
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(
+        const_iterator __p, __node_pointer __cp)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "unordered container::emplace_hint(const_iterator, args...) called with an iterator not"
+        " referring to this unordered container");
+#endif
+    if (__p != end() && key_eq()(*__p, __cp->__value_))
+    {
+        __next_pointer __np = __p.__node_;
+        __cp->__hash_ = __np->__hash();
+        size_type __bc = bucket_count();
+        if (size()+1 > __bc * max_load_factor() || __bc == 0)
+        {
+            rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
+                           size_type(ceil(float(size() + 1) / max_load_factor()))));
+            __bc = bucket_count();
+        }
+        size_t __chash = __constrain_hash(__cp->__hash_, __bc);
+        __next_pointer __pp = __bucket_list_[__chash];
+        while (__pp->__next_ != __np)
+            __pp = __pp->__next_;
+        __cp->__next_ = __np;
+        __pp->__next_ = static_cast<__next_pointer>(__cp);
+        ++size();
+#if _LIBCPP_DEBUG_LEVEL == 2
+        return iterator(static_cast<__next_pointer>(__cp), this);
+#else
+        return iterator(static_cast<__next_pointer>(__cp));
+#endif
+    }
+    return __node_insert_multi(__cp);
+}
+
+
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _Key, class ..._Args>
+pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const& __k, _Args&&... __args)
+{
+
+    size_t __hash = hash_function()(__k);
+    size_type __bc = bucket_count();
+    bool __inserted = false;
+    __next_pointer __nd;
+    size_t __chash;
+    if (__bc != 0)
+    {
+        __chash = __constrain_hash(__hash, __bc);
+        __nd = __bucket_list_[__chash];
+        if (__nd != nullptr)
+        {
+            for (__nd = __nd->__next_; __nd != nullptr &&
+                (__nd->__hash() == __hash || __constrain_hash(__nd->__hash(), __bc) == __chash);
+                                                           __nd = __nd->__next_)
+            {
+                if (key_eq()(__nd->__upcast()->__value_, __k))
+                    goto __done;
+            }
+        }
+    }
+    {
+        __node_holder __h = __construct_node_hash(__hash, _VSTD::forward<_Args>(__args)...);
+        if (size()+1 > __bc * max_load_factor() || __bc == 0)
+        {
+            rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
+                           size_type(ceil(float(size() + 1) / max_load_factor()))));
+            __bc = bucket_count();
+            __chash = __constrain_hash(__hash, __bc);
+        }
+        // insert_after __bucket_list_[__chash], or __first_node if bucket is null
+        __next_pointer __pn = __bucket_list_[__chash];
+        if (__pn == nullptr)
+        {
+            __pn = __p1_.first().__ptr();
+            __h->__next_ = __pn->__next_;
+            __pn->__next_ = __h.get()->__ptr();
+            // fix up __bucket_list_
+            __bucket_list_[__chash] = __pn;
+            if (__h->__next_ != nullptr)
+                __bucket_list_[__constrain_hash(__h->__next_->__hash(), __bc)]
+                    = __h.get()->__ptr();
+        }
+        else
+        {
+            __h->__next_ = __pn->__next_;
+            __pn->__next_ = static_cast<__next_pointer>(__h.get());
+        }
+        __nd = static_cast<__next_pointer>(__h.release());
+        // increment size
+        ++size();
+        __inserted = true;
+    }
+__done:
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return pair<iterator, bool>(iterator(__nd, this), __inserted);
+#else
+    return pair<iterator, bool>(iterator(__nd), __inserted);
+#endif
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class... _Args>
+pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_impl(_Args&&... __args)
+{
+    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
+    pair<iterator, bool> __r = __node_insert_unique(__h.get());
+    if (__r.second)
+        __h.release();
+    return __r;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class... _Args>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_multi(_Args&&... __args)
+{
+    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
+    iterator __r = __node_insert_multi(__h.get());
+    __h.release();
+    return __r;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class... _Args>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_hint_multi(
+        const_iterator __p, _Args&&... __args)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "unordered container::emplace_hint(const_iterator, args...) called with an iterator not"
+        " referring to this unordered container");
+#endif
+    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
+    iterator __r = __node_insert_multi(__p, __h.get());
+    __h.release();
+    return __r;
+}
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _NodeHandle, class _InsertReturnType>
+_LIBCPP_INLINE_VISIBILITY
+_InsertReturnType
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_unique(
+    _NodeHandle&& __nh)
+{
+    if (__nh.empty())
+        return _InsertReturnType{end(), false, _NodeHandle()};
+    pair<iterator, bool> __result = __node_insert_unique(__nh.__ptr_);
+    if (__result.second)
+        __nh.__release_ptr();
+    return _InsertReturnType{__result.first, __result.second, _VSTD::move(__nh)};
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _NodeHandle>
+_LIBCPP_INLINE_VISIBILITY
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_unique(
+    const_iterator, _NodeHandle&& __nh)
+{
+    if (__nh.empty())
+        return end();
+    pair<iterator, bool> __result = __node_insert_unique(__nh.__ptr_);
+    if (__result.second)
+        __nh.__release_ptr();
+    return __result.first;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _NodeHandle>
+_LIBCPP_INLINE_VISIBILITY
+_NodeHandle
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_extract(
+    key_type const& __key)
+{
+    iterator __i = find(__key);
+    if (__i == end())
+        return _NodeHandle();
+    return __node_handle_extract<_NodeHandle>(__i);
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _NodeHandle>
+_LIBCPP_INLINE_VISIBILITY
+_NodeHandle
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_extract(
+    const_iterator __p)
+{
+    allocator_type __alloc(__node_alloc());
+    return _NodeHandle(remove(__p).release(), __alloc);
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _Table>
+_LIBCPP_INLINE_VISIBILITY
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_merge_unique(
+    _Table& __source)
+{
+    static_assert(is_same<__node, typename _Table::__node>::value, "");
+
+    for (typename _Table::iterator __it = __source.begin();
+         __it != __source.end();)
+    {
+        __node_pointer __src_ptr = __it.__node_->__upcast();
+        size_t __hash = hash_function()(__src_ptr->__value_);
+        __next_pointer __existing_node =
+            __node_insert_unique_prepare(__hash, __src_ptr->__value_);
+        auto __prev_iter = __it++;
+        if (__existing_node == nullptr)
+        {
+            (void)__source.remove(__prev_iter).release();
+            __src_ptr->__hash_ = __hash;
+            __node_insert_unique_perform(__src_ptr);
+        }
+    }
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _NodeHandle>
+_LIBCPP_INLINE_VISIBILITY
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_multi(
+    _NodeHandle&& __nh)
+{
+    if (__nh.empty())
+        return end();
+    iterator __result = __node_insert_multi(__nh.__ptr_);
+    __nh.__release_ptr();
+    return __result;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _NodeHandle>
+_LIBCPP_INLINE_VISIBILITY
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_multi(
+    const_iterator __hint, _NodeHandle&& __nh)
+{
+    if (__nh.empty())
+        return end();
+    iterator __result = __node_insert_multi(__hint, __nh.__ptr_);
+    __nh.__release_ptr();
+    return __result;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _Table>
+_LIBCPP_INLINE_VISIBILITY
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_merge_multi(
+    _Table& __source)
+{
+    static_assert(is_same<typename _Table::__node, __node>::value, "");
+
+    for (typename _Table::iterator __it = __source.begin();
+         __it != __source.end();)
+    {
+        __node_pointer __src_ptr = __it.__node_->__upcast();
+        size_t __src_hash = hash_function()(__src_ptr->__value_);
+        __next_pointer __pn =
+            __node_insert_multi_prepare(__src_hash, __src_ptr->__value_);
+        (void)__source.remove(__it++).release();
+        __src_ptr->__hash_ = __src_hash;
+        __node_insert_multi_perform(__src_ptr, __pn);
+    }
+}
+#endif // _LIBCPP_STD_VER > 14
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::rehash(size_type __n)
+_LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+{
+    if (__n == 1)
+        __n = 2;
+    else if (__n & (__n - 1))
+        __n = __next_prime(__n);
+    size_type __bc = bucket_count();
+    if (__n > __bc)
+        __rehash(__n);
+    else if (__n < __bc)
+    {
+        __n = _VSTD::max<size_type>
+              (
+                  __n,
+                  __is_hash_power2(__bc) ? __next_hash_pow2(size_t(ceil(float(size()) / max_load_factor()))) :
+                                           __next_prime(size_t(ceil(float(size()) / max_load_factor())))
+              );
+        if (__n < __bc)
+            __rehash(__n);
+    }
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__rehash(size_type __nbc)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__invalidate_all(this);
+#endif
+    __pointer_allocator& __npa = __bucket_list_.get_deleter().__alloc();
+    __bucket_list_.reset(__nbc > 0 ?
+                      __pointer_alloc_traits::allocate(__npa, __nbc) : nullptr);
+    __bucket_list_.get_deleter().size() = __nbc;
+    if (__nbc > 0)
+    {
+        for (size_type __i = 0; __i < __nbc; ++__i)
+            __bucket_list_[__i] = nullptr;
+        __next_pointer __pp = __p1_.first().__ptr();
+        __next_pointer __cp = __pp->__next_;
+        if (__cp != nullptr)
+        {
+            size_type __chash = __constrain_hash(__cp->__hash(), __nbc);
+            __bucket_list_[__chash] = __pp;
+            size_type __phash = __chash;
+            for (__pp = __cp, void(), __cp = __cp->__next_; __cp != nullptr;
+                                                           __cp = __pp->__next_)
+            {
+                __chash = __constrain_hash(__cp->__hash(), __nbc);
+                if (__chash == __phash)
+                    __pp = __cp;
+                else
+                {
+                    if (__bucket_list_[__chash] == nullptr)
+                    {
+                        __bucket_list_[__chash] = __pp;
+                        __pp = __cp;
+                        __phash = __chash;
+                    }
+                    else
+                    {
+                        __next_pointer __np = __cp;
+                        for (; __np->__next_ != nullptr &&
+                               key_eq()(__cp->__upcast()->__value_,
+                                        __np->__next_->__upcast()->__value_);
+                                                           __np = __np->__next_)
+                            ;
+                        __pp->__next_ = __np->__next_;
+                        __np->__next_ = __bucket_list_[__chash]->__next_;
+                        __bucket_list_[__chash]->__next_ = __cp;
+
+                    }
+                }
+            }
+        }
+    }
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _Key>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k)
+{
+    size_t __hash = hash_function()(__k);
+    size_type __bc = bucket_count();
+    if (__bc != 0)
+    {
+        size_t __chash = __constrain_hash(__hash, __bc);
+        __next_pointer __nd = __bucket_list_[__chash];
+        if (__nd != nullptr)
+        {
+            for (__nd = __nd->__next_; __nd != nullptr &&
+                (__nd->__hash() == __hash
+                  || __constrain_hash(__nd->__hash(), __bc) == __chash);
+                                                           __nd = __nd->__next_)
+            {
+                if ((__nd->__hash() == __hash)
+                    && key_eq()(__nd->__upcast()->__value_, __k))
+#if _LIBCPP_DEBUG_LEVEL == 2
+                    return iterator(__nd, this);
+#else
+                    return iterator(__nd);
+#endif
+            }
+        }
+    }
+    return end();
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _Key>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k) const
+{
+    size_t __hash = hash_function()(__k);
+    size_type __bc = bucket_count();
+    if (__bc != 0)
+    {
+        size_t __chash = __constrain_hash(__hash, __bc);
+        __next_pointer __nd = __bucket_list_[__chash];
+        if (__nd != nullptr)
+        {
+            for (__nd = __nd->__next_; __nd != nullptr &&
+                (__hash == __nd->__hash()
+                    || __constrain_hash(__nd->__hash(), __bc) == __chash);
+                                                           __nd = __nd->__next_)
+            {
+                if ((__nd->__hash() == __hash)
+                    && key_eq()(__nd->__upcast()->__value_, __k))
+#if _LIBCPP_DEBUG_LEVEL == 2
+                    return const_iterator(__nd, this);
+#else
+                    return const_iterator(__nd);
+#endif
+            }
+        }
+
+    }
+    return end();
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class ..._Args>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node(_Args&& ...__args)
+{
+    static_assert(!__is_hash_value_type<_Args...>::value,
+                  "Construct cannot be called with a hash value type");
+    __node_allocator& __na = __node_alloc();
+    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
+    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), _VSTD::forward<_Args>(__args)...);
+    __h.get_deleter().__value_constructed = true;
+    __h->__hash_ = hash_function()(__h->__value_);
+    __h->__next_ = nullptr;
+    return __h;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _First, class ..._Rest>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(
+    size_t __hash, _First&& __f, _Rest&& ...__rest)
+{
+    static_assert(!__is_hash_value_type<_First, _Rest...>::value,
+                  "Construct cannot be called with a hash value type");
+    __node_allocator& __na = __node_alloc();
+    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
+    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_),
+                             _VSTD::forward<_First>(__f),
+                             _VSTD::forward<_Rest>(__rest)...);
+    __h.get_deleter().__value_constructed = true;
+    __h->__hash_ = __hash;
+    __h->__next_ = nullptr;
+    return __h;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __p)
+{
+    __next_pointer __np = __p.__node_;
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "unordered container erase(iterator) called with an iterator not"
+        " referring to this container");
+    _LIBCPP_ASSERT(__p != end(),
+        "unordered container erase(iterator) called with a non-dereferenceable iterator");
+    iterator __r(__np, this);
+#else
+    iterator __r(__np);
+#endif
+    ++__r;
+    remove(__p);
+    return __r;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __first,
+                                                const_iterator __last)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__first) == this,
+        "unordered container::erase(iterator, iterator) called with an iterator not"
+        " referring to this container");
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__last) == this,
+        "unordered container::erase(iterator, iterator) called with an iterator not"
+        " referring to this container");
+#endif
+    for (const_iterator __p = __first; __first != __last; __p = __first)
+    {
+        ++__first;
+        erase(__p);
+    }
+    __next_pointer __np = __last.__node_;
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator (__np, this);
+#else
+    return iterator (__np);
+#endif
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _Key>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_unique(const _Key& __k)
+{
+    iterator __i = find(__k);
+    if (__i == end())
+        return 0;
+    erase(__i);
+    return 1;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _Key>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_multi(const _Key& __k)
+{
+    size_type __r = 0;
+    iterator __i = find(__k);
+    if (__i != end())
+    {
+        iterator __e = end();
+        do
+        {
+            erase(__i++);
+            ++__r;
+        } while (__i != __e && key_eq()(*__i, __k));
+    }
+    return __r;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::remove(const_iterator __p) _NOEXCEPT
+{
+    // current node
+    __next_pointer __cn = __p.__node_;
+    size_type __bc = bucket_count();
+    size_t __chash = __constrain_hash(__cn->__hash(), __bc);
+    // find previous node
+    __next_pointer __pn = __bucket_list_[__chash];
+    for (; __pn->__next_ != __cn; __pn = __pn->__next_)
+        ;
+    // Fix up __bucket_list_
+        // if __pn is not in same bucket (before begin is not in same bucket) &&
+        //    if __cn->__next_ is not in same bucket (nullptr is not in same bucket)
+    if (__pn == __p1_.first().__ptr()
+            || __constrain_hash(__pn->__hash(), __bc) != __chash)
+    {
+        if (__cn->__next_ == nullptr
+            || __constrain_hash(__cn->__next_->__hash(), __bc) != __chash)
+            __bucket_list_[__chash] = nullptr;
+    }
+        // if __cn->__next_ is not in same bucket (nullptr is in same bucket)
+    if (__cn->__next_ != nullptr)
+    {
+        size_t __nhash = __constrain_hash(__cn->__next_->__hash(), __bc);
+        if (__nhash != __chash)
+            __bucket_list_[__nhash] = __pn;
+    }
+    // remove __cn
+    __pn->__next_ = __cn->__next_;
+    __cn->__next_ = nullptr;
+    --size();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __c_node* __c = __get_db()->__find_c_and_lock(this);
+    for (__i_node** __dp = __c->end_; __dp != __c->beg_; )
+    {
+        --__dp;
+        iterator* __i = static_cast<iterator*>((*__dp)->__i_);
+        if (__i->__node_ == __cn)
+        {
+            (*__dp)->__c_ = nullptr;
+            if (--__c->end_ != __dp)
+                _VSTD::memmove(__dp, __dp+1, (__c->end_ - __dp)*sizeof(__i_node*));
+        }
+    }
+    __get_db()->unlock();
+#endif
+    return __node_holder(__cn->__upcast(), _Dp(__node_alloc(), true));
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _Key>
+inline
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_unique(const _Key& __k) const
+{
+    return static_cast<size_type>(find(__k) != end());
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _Key>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_multi(const _Key& __k) const
+{
+    size_type __r = 0;
+    const_iterator __i = find(__k);
+    if (__i != end())
+    {
+        const_iterator __e = end();
+        do
+        {
+            ++__i;
+            ++__r;
+        } while (__i != __e && key_eq()(*__i, __k));
+    }
+    return __r;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _Key>
+pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
+     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(
+        const _Key& __k)
+{
+    iterator __i = find(__k);
+    iterator __j = __i;
+    if (__i != end())
+        ++__j;
+    return pair<iterator, iterator>(__i, __j);
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _Key>
+pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
+     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(
+        const _Key& __k) const
+{
+    const_iterator __i = find(__k);
+    const_iterator __j = __i;
+    if (__i != end())
+        ++__j;
+    return pair<const_iterator, const_iterator>(__i, __j);
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _Key>
+pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
+     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(
+        const _Key& __k)
+{
+    iterator __i = find(__k);
+    iterator __j = __i;
+    if (__i != end())
+    {
+        iterator __e = end();
+        do
+        {
+            ++__j;
+        } while (__j != __e && key_eq()(*__j, __k));
+    }
+    return pair<iterator, iterator>(__i, __j);
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+template <class _Key>
+pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
+     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(
+        const _Key& __k) const
+{
+    const_iterator __i = find(__k);
+    const_iterator __j = __i;
+    if (__i != end())
+    {
+        const_iterator __e = end();
+        do
+        {
+            ++__j;
+        } while (__j != __e && key_eq()(*__j, __k));
+    }
+    return pair<const_iterator, const_iterator>(__i, __j);
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+void
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::swap(__hash_table& __u)
+#if _LIBCPP_STD_VER <= 11
+    _NOEXCEPT_(
+        __is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value
+        && (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value
+              || __is_nothrow_swappable<__pointer_allocator>::value)
+        && (!__node_traits::propagate_on_container_swap::value
+              || __is_nothrow_swappable<__node_allocator>::value)
+            )
+#else
+  _NOEXCEPT_(__is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value)
+#endif
+{
+    _LIBCPP_ASSERT(__node_traits::propagate_on_container_swap::value ||
+                   this->__node_alloc() == __u.__node_alloc(),
+                   "list::swap: Either propagate_on_container_swap must be true"
+                   " or the allocators must compare equal");
+    {
+    __node_pointer_pointer __npp = __bucket_list_.release();
+    __bucket_list_.reset(__u.__bucket_list_.release());
+    __u.__bucket_list_.reset(__npp);
+    }
+    _VSTD::swap(__bucket_list_.get_deleter().size(), __u.__bucket_list_.get_deleter().size());
+    _VSTD::__swap_allocator(__bucket_list_.get_deleter().__alloc(),
+             __u.__bucket_list_.get_deleter().__alloc());
+    _VSTD::__swap_allocator(__node_alloc(), __u.__node_alloc());
+    _VSTD::swap(__p1_.first().__next_, __u.__p1_.first().__next_);
+    __p2_.swap(__u.__p2_);
+    __p3_.swap(__u.__p3_);
+    if (size() > 0)
+        __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
+            __p1_.first().__ptr();
+    if (__u.size() > 0)
+        __u.__bucket_list_[__constrain_hash(__u.__p1_.first().__next_->__hash(), __u.bucket_count())] =
+            __u.__p1_.first().__ptr();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->swap(this, &__u);
+#endif
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::bucket_size(size_type __n) const
+{
+    _LIBCPP_ASSERT(__n < bucket_count(),
+        "unordered container::bucket_size(n) called with n >= bucket_count()");
+    __next_pointer __np = __bucket_list_[__n];
+    size_type __bc = bucket_count();
+    size_type __r = 0;
+    if (__np != nullptr)
+    {
+        for (__np = __np->__next_; __np != nullptr &&
+                                   __constrain_hash(__np->__hash(), __bc) == __n;
+                                                    __np = __np->__next_, (void) ++__r)
+            ;
+    }
+    return __r;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(__hash_table<_Tp, _Hash, _Equal, _Alloc>& __x,
+     __hash_table<_Tp, _Hash, _Equal, _Alloc>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+bool
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__dereferenceable(const const_iterator* __i) const
+{
+    return __i->__node_ != nullptr;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+bool
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__decrementable(const const_iterator*) const
+{
+    return false;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+bool
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__addable(const const_iterator*, ptrdiff_t) const
+{
+    return false;
+}
+
+template <class _Tp, class _Hash, class _Equal, class _Alloc>
+bool
+__hash_table<_Tp, _Hash, _Equal, _Alloc>::__subscriptable(const const_iterator*, ptrdiff_t) const
+{
+    return false;
+}
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP__HASH_TABLE
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/access.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/access.h
new file mode 100644
index 00000000000..5e0d6b35153
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/access.h
@@ -0,0 +1,129 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_ACCESS_H
+#define _LIBCPP___ITERATOR_ACCESS_H
+
+#include <__config>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, size_t _Np>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp*
+begin(_Tp (&__array)[_Np])
+{
+    return __array;
+}
+
+template <class _Tp, size_t _Np>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp*
+end(_Tp (&__array)[_Np])
+{
+    return __array + _Np;
+}
+
+#if !defined(_LIBCPP_CXX03_LANG)
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+auto
+begin(_Cp& __c) -> decltype(__c.begin())
+{
+    return __c.begin();
+}
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+auto
+begin(const _Cp& __c) -> decltype(__c.begin())
+{
+    return __c.begin();
+}
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+auto
+end(_Cp& __c) -> decltype(__c.end())
+{
+    return __c.end();
+}
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+auto
+end(const _Cp& __c) -> decltype(__c.end())
+{
+    return __c.end();
+}
+
+#if _LIBCPP_STD_VER > 11
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+auto cbegin(const _Cp& __c) -> decltype(_VSTD::begin(__c))
+{
+    return _VSTD::begin(__c);
+}
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+auto cend(const _Cp& __c) -> decltype(_VSTD::end(__c))
+{
+    return _VSTD::end(__c);
+}
+
+#endif
+
+
+#else  // defined(_LIBCPP_CXX03_LANG)
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY
+typename _Cp::iterator
+begin(_Cp& __c)
+{
+    return __c.begin();
+}
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY
+typename _Cp::const_iterator
+begin(const _Cp& __c)
+{
+    return __c.begin();
+}
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY
+typename _Cp::iterator
+end(_Cp& __c)
+{
+    return __c.end();
+}
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY
+typename _Cp::const_iterator
+end(const _Cp& __c)
+{
+    return __c.end();
+}
+
+#endif // !defined(_LIBCPP_CXX03_LANG)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_ACCESS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/advance.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/advance.h
new file mode 100644
index 00000000000..b38540fbe39
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/advance.h
@@ -0,0 +1,195 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_ADVANCE_H
+#define _LIBCPP___ITERATOR_ADVANCE_H
+
+#include <__config>
+#include <__debug>
+#include <__function_like.h>
+#include <__iterator/concepts.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/move.h>
+#include <cstdlib>
+#include <concepts>
+#include <limits>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIter>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
+void __advance(_InputIter& __i, typename iterator_traits<_InputIter>::difference_type __n, input_iterator_tag) {
+  for (; __n > 0; --__n)
+    ++__i;
+}
+
+template <class _BiDirIter>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
+void __advance(_BiDirIter& __i, typename iterator_traits<_BiDirIter>::difference_type __n, bidirectional_iterator_tag) {
+  if (__n >= 0)
+    for (; __n > 0; --__n)
+      ++__i;
+  else
+    for (; __n < 0; ++__n)
+      --__i;
+}
+
+template <class _RandIter>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
+void __advance(_RandIter& __i, typename iterator_traits<_RandIter>::difference_type __n, random_access_iterator_tag) {
+  __i += __n;
+}
+
+template <
+    class _InputIter, class _Distance,
+    class _IntegralDistance = decltype(_VSTD::__convert_to_integral(declval<_Distance>())),
+    class = __enable_if_t<is_integral<_IntegralDistance>::value> >
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
+void advance(_InputIter& __i, _Distance __orig_n) {
+  typedef typename iterator_traits<_InputIter>::difference_type _Difference;
+  _Difference __n = static_cast<_Difference>(_VSTD::__convert_to_integral(__orig_n));
+  _LIBCPP_ASSERT(__n >= 0 || __is_cpp17_bidirectional_iterator<_InputIter>::value,
+                 "Attempt to advance(it, n) with negative n on a non-bidirectional iterator");
+  _VSTD::__advance(__i, __n, typename iterator_traits<_InputIter>::iterator_category());
+}
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+// [range.iter.op.advance]
+struct __advance_fn final : private __function_like {
+private:
+  template <class _Tp>
+  _LIBCPP_HIDE_FROM_ABI
+  static constexpr _Tp __magnitude_geq(_Tp __a, _Tp __b) noexcept {
+    return __a < 0 ? (__a <= __b) : (__a >= __b);
+  }
+
+  template <class _Ip>
+  _LIBCPP_HIDE_FROM_ABI
+  static constexpr void __advance_forward(_Ip& __i, iter_difference_t<_Ip> __n) {
+    while (__n > 0) {
+      --__n;
+      ++__i;
+    }
+  }
+
+  template <class _Ip>
+  _LIBCPP_HIDE_FROM_ABI
+  static constexpr void __advance_backward(_Ip& __i, iter_difference_t<_Ip> __n) {
+    while (__n < 0) {
+      ++__n;
+      --__i;
+    }
+  }
+
+public:
+  constexpr explicit __advance_fn(__tag __x) noexcept : __function_like(__x) {}
+
+  // Preconditions: If `I` does not model `bidirectional_iterator`, `n` is not negative.
+  template <input_or_output_iterator _Ip>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr void operator()(_Ip& __i, iter_difference_t<_Ip> __n) const {
+    _LIBCPP_ASSERT(__n >= 0 || bidirectional_iterator<_Ip>,
+                   "If `n < 0`, then `bidirectional_iterator<I>` must be true.");
+
+    // If `I` models `random_access_iterator`, equivalent to `i += n`.
+    if constexpr (random_access_iterator<_Ip>) {
+      __i += __n;
+      return;
+    } else if constexpr (bidirectional_iterator<_Ip>) {
+      // Otherwise, if `n` is non-negative, increments `i` by `n`.
+      __advance_forward(__i, __n);
+      // Otherwise, decrements `i` by `-n`.
+      __advance_backward(__i, __n);
+      return;
+    } else {
+      // Otherwise, if `n` is non-negative, increments `i` by `n`.
+      __advance_forward(__i, __n);
+      return;
+    }
+  }
+
+  // Preconditions: Either `assignable_from<I&, S> || sized_sentinel_for<S, I>` is modeled, or [i, bound) denotes a range.
+  template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr void operator()(_Ip& __i, _Sp ___bound) const {
+    // If `I` and `S` model `assignable_from<I&, S>`, equivalent to `i = std::move(bound)`.
+    if constexpr (assignable_from<_Ip&, _Sp>) {
+      __i = _VSTD::move(___bound);
+    }
+    // Otherwise, if `S` and `I` model `sized_sentinel_for<S, I>`, equivalent to `ranges::advance(i, bound - i)`.
+    else if constexpr (sized_sentinel_for<_Sp, _Ip>) {
+      (*this)(__i, ___bound - __i);
+    }
+    // Otherwise, while `bool(i != bound)` is true, increments `i`.
+    else {
+      while (__i != ___bound) {
+        ++__i;
+      }
+    }
+  }
+
+  // Preconditions:
+  //   * If `n > 0`, [i, bound) denotes a range.
+  //   * If `n == 0`, [i, bound) or [bound, i) denotes a range.
+  //   * If `n < 0`, [bound, i) denotes a range, `I` models `bidirectional_iterator`, and `I` and `S` model `same_as<I, S>`.
+  // Returns: `n - M`, where `M` is the difference between the the ending and starting position.
+  template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr iter_difference_t<_Ip> operator()(_Ip& __i, iter_difference_t<_Ip> __n, _Sp ___bound) const {
+    _LIBCPP_ASSERT((__n >= 0) || (bidirectional_iterator<_Ip> && same_as<_Ip, _Sp>),
+                   "If `n < 0`, then `bidirectional_iterator<I> && same_as<I, S>` must be true.");
+    // If `S` and `I` model `sized_sentinel_for<S, I>`:
+    if constexpr (sized_sentinel_for<_Sp, _Ip>) {
+      // If |n| >= |bound - i|, equivalent to `ranges::advance(i, bound)`.
+      if (const auto __M = ___bound - __i; __magnitude_geq(__n, __M)) {
+        (*this)(__i, ___bound);
+        return __n - __M;
+      }
+
+      // Otherwise, equivalent to `ranges::advance(i, n)`.
+      (*this)(__i, __n);
+      return 0;
+    } else {
+      // Otherwise, if `n` is non-negative, while `bool(i != bound)` is true, increments `i` but at
+      // most `n` times.
+      while (__i != ___bound && __n > 0) {
+        ++__i;
+        --__n;
+      }
+
+      // Otherwise, while `bool(i != bound)` is true, decrements `i` but at most `-n` times.
+      if constexpr (bidirectional_iterator<_Ip> && same_as<_Ip, _Sp>) {
+        while (__i != ___bound && __n < 0) {
+          --__i;
+          ++__n;
+        }
+      }
+      return __n;
+    }
+
+    _LIBCPP_UNREACHABLE();
+  }
+};
+
+inline constexpr auto advance = __advance_fn(__function_like::__tag());
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_ADVANCE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/back_insert_iterator.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/back_insert_iterator.h
new file mode 100644
index 00000000000..844babe5c5e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/back_insert_iterator.h
@@ -0,0 +1,70 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_BACK_INSERT_ITERATOR_H
+#define _LIBCPP___ITERATOR_BACK_INSERT_ITERATOR_H
+
+#include <__config>
+#include <__iterator/iterator.h>
+#include <__iterator/iterator_traits.h>
+#include <__memory/addressof.h>
+#include <__utility/move.h>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Container>
+class _LIBCPP_TEMPLATE_VIS back_insert_iterator
+#if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
+    : public iterator<output_iterator_tag, void, void, void, void>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+protected:
+    _Container* container;
+public:
+    typedef output_iterator_tag iterator_category;
+    typedef void value_type;
+#if _LIBCPP_STD_VER > 17
+    typedef ptrdiff_t difference_type;
+#else
+    typedef void difference_type;
+#endif
+    typedef void pointer;
+    typedef void reference;
+    typedef _Container container_type;
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 explicit back_insert_iterator(_Container& __x) : container(_VSTD::addressof(__x)) {}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 back_insert_iterator& operator=(const typename _Container::value_type& __value_)
+        {container->push_back(__value_); return *this;}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 back_insert_iterator& operator=(typename _Container::value_type&& __value_)
+        {container->push_back(_VSTD::move(__value_)); return *this;}
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 back_insert_iterator& operator*()     {return *this;}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 back_insert_iterator& operator++()    {return *this;}
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 back_insert_iterator  operator++(int) {return *this;}
+};
+
+template <class _Container>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
+back_insert_iterator<_Container>
+back_inserter(_Container& __x)
+{
+    return back_insert_iterator<_Container>(__x);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_BACK_INSERT_ITERATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/common_iterator.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/common_iterator.h
new file mode 100644
index 00000000000..9a142769e55
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/common_iterator.h
@@ -0,0 +1,296 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_COMMON_ITERATOR_H
+#define _LIBCPP___ITERATOR_COMMON_ITERATOR_H
+
+#include <__config>
+#include <__debug>
+#include <__iterator/concepts.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/iter_move.h>
+#include <__iterator/iter_swap.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/readable_traits.h>
+#include <concepts>
+#include <variant>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent>
+  requires (!same_as<_Iter, _Sent> && copyable<_Iter>)
+class common_iterator {
+  class __proxy {
+    friend common_iterator;
+
+    iter_value_t<_Iter> __value;
+    // We can move __x because the only caller verifies that __x is not a reference.
+    constexpr __proxy(iter_reference_t<_Iter>&& __x)
+      : __value(_VSTD::move(__x)) {}
+
+  public:
+    const iter_value_t<_Iter>* operator->() const {
+      return _VSTD::addressof(__value);
+    }
+  };
+
+  class __postfix_proxy {
+    friend common_iterator;
+
+    iter_value_t<_Iter> __value;
+    constexpr __postfix_proxy(iter_reference_t<_Iter>&& __x)
+      : __value(_VSTD::forward<iter_reference_t<_Iter>>(__x)) {}
+
+  public:
+    constexpr static bool __valid_for_iter =
+      constructible_from<iter_value_t<_Iter>, iter_reference_t<_Iter>> &&
+      move_constructible<iter_value_t<_Iter>>;
+
+    const iter_value_t<_Iter>& operator*() const {
+      return __value;
+    }
+  };
+
+public:
+  variant<_Iter, _Sent> __hold_;
+
+  common_iterator() requires default_initializable<_Iter> = default;
+
+  constexpr common_iterator(_Iter __i) : __hold_(in_place_type<_Iter>, _VSTD::move(__i)) {}
+  constexpr common_iterator(_Sent __s) : __hold_(in_place_type<_Sent>, _VSTD::move(__s)) {}
+
+  template<class _I2, class _S2>
+    requires convertible_to<const _I2&, _Iter> && convertible_to<const _S2&, _Sent>
+  constexpr common_iterator(const common_iterator<_I2, _S2>& __other)
+    : __hold_([&]() -> variant<_Iter, _Sent> {
+      _LIBCPP_ASSERT(!__other.__hold_.valueless_by_exception(), "Constructed from valueless iterator.");
+      if (__other.__hold_.index() == 0)
+        return variant<_Iter, _Sent>{in_place_index<0>, _VSTD::__unchecked_get<0>(__other.__hold_)};
+      return variant<_Iter, _Sent>{in_place_index<1>, _VSTD::__unchecked_get<1>(__other.__hold_)};
+    }()) {}
+
+  template<class _I2, class _S2>
+    requires convertible_to<const _I2&, _Iter> && convertible_to<const _S2&, _Sent> &&
+             assignable_from<_Iter&, const _I2&> && assignable_from<_Sent&, const _S2&>
+  common_iterator& operator=(const common_iterator<_I2, _S2>& __other) {
+    _LIBCPP_ASSERT(!__other.__hold_.valueless_by_exception(), "Assigned from valueless iterator.");
+
+    auto __idx = __hold_.index();
+    auto __other_idx = __other.__hold_.index();
+
+    // If they're the same index, just assign.
+    if (__idx == 0 && __other_idx == 0)
+      _VSTD::__unchecked_get<0>(__hold_) = _VSTD::__unchecked_get<0>(__other.__hold_);
+    else if (__idx == 1 && __other_idx == 1)
+      _VSTD::__unchecked_get<1>(__hold_) = _VSTD::__unchecked_get<1>(__other.__hold_);
+
+    // Otherwise replace with the oposite element.
+    else if (__other_idx == 1)
+      __hold_.template emplace<1>(_VSTD::__unchecked_get<1>(__other.__hold_));
+    else if (__other_idx == 0)
+      __hold_.template emplace<0>(_VSTD::__unchecked_get<0>(__other.__hold_));
+
+    return *this;
+  }
+
+  decltype(auto) operator*()
+  {
+    _LIBCPP_ASSERT(holds_alternative<_Iter>(__hold_),
+                   "Cannot dereference sentinel. Common iterator not holding an iterator.");
+    return *_VSTD::__unchecked_get<_Iter>(__hold_);
+  }
+
+  decltype(auto) operator*() const
+    requires __dereferenceable<const _Iter>
+  {
+    _LIBCPP_ASSERT(holds_alternative<_Iter>(__hold_),
+                   "Cannot dereference sentinel. Common iterator not holding an iterator.");
+    return *_VSTD::__unchecked_get<_Iter>(__hold_);
+  }
+
+  template<class _I2 = _Iter>
+  decltype(auto) operator->() const
+    requires indirectly_readable<const _I2> &&
+    (requires(const _I2& __i) { __i.operator->(); } ||
+     is_reference_v<iter_reference_t<_I2>> ||
+     constructible_from<iter_value_t<_I2>, iter_reference_t<_I2>>)
+  {
+    _LIBCPP_ASSERT(holds_alternative<_Iter>(__hold_),
+                   "Cannot dereference sentinel. Common iterator not holding an iterator.");
+
+    if constexpr (is_pointer_v<_Iter> || requires(const _Iter& __i) { __i.operator->(); })    {
+      return _VSTD::__unchecked_get<_Iter>(__hold_);
+    } else if constexpr (is_reference_v<iter_reference_t<_Iter>>) {
+      auto&& __tmp = *_VSTD::__unchecked_get<_Iter>(__hold_);
+      return _VSTD::addressof(__tmp);
+    } else {
+      return __proxy(*_VSTD::__unchecked_get<_Iter>(__hold_));
+    }
+  }
+
+  common_iterator& operator++() {
+    _LIBCPP_ASSERT(holds_alternative<_Iter>(__hold_),
+                   "Cannot increment sentinel. Common iterator not holding an iterator.");
+    ++_VSTD::__unchecked_get<_Iter>(__hold_); return *this;
+  }
+
+  decltype(auto) operator++(int) {
+    _LIBCPP_ASSERT(holds_alternative<_Iter>(__hold_),
+                   "Cannot increment sentinel. Common iterator not holding an iterator.");
+
+    if constexpr (forward_iterator<_Iter>) {
+      auto __tmp = *this;
+      ++*this;
+      return __tmp;
+    } else if constexpr (requires (_Iter& __i) { { *__i++ } -> __referenceable; } ||
+                         !__postfix_proxy::__valid_for_iter) {
+      return _VSTD::__unchecked_get<_Iter>(__hold_)++;
+    } else {
+      __postfix_proxy __p(**this);
+      ++*this;
+      return __p;
+    }
+  }
+
+  template<class _I2, sentinel_for<_Iter> _S2>
+    requires sentinel_for<_Sent, _I2>
+  friend bool operator==(const common_iterator& __x, const common_iterator<_I2, _S2>& __y) {
+    _LIBCPP_ASSERT(!__x.__hold_.valueless_by_exception() &&
+                   !__y.__hold_.valueless_by_exception(),
+                   "One or both common_iterators are valueless. (Cannot compare valueless iterators.)");
+
+    auto __x_index = __x.__hold_.index();
+    auto __y_index = __y.__hold_.index();
+
+    if (__x_index == __y_index)
+      return true;
+
+    if (__x_index == 0)
+      return _VSTD::__unchecked_get<_Iter>(__x.__hold_) == _VSTD::__unchecked_get<_S2>(__y.__hold_);
+
+    return _VSTD::__unchecked_get<_Sent>(__x.__hold_) == _VSTD::__unchecked_get<_I2>(__y.__hold_);
+  }
+
+  template<class _I2, sentinel_for<_Iter> _S2>
+    requires sentinel_for<_Sent, _I2> && equality_comparable_with<_Iter, _I2>
+  friend bool operator==(const common_iterator& __x, const common_iterator<_I2, _S2>& __y) {
+    _LIBCPP_ASSERT(!__x.__hold_.valueless_by_exception() &&
+                   !__y.__hold_.valueless_by_exception(),
+                   "One or both common_iterators are valueless. (Cannot compare valueless iterators.)");
+
+    auto __x_index = __x.__hold_.index();
+    auto __y_index = __y.__hold_.index();
+
+    if (__x_index == 1 && __y_index == 1)
+      return true;
+
+    if (__x_index == 0 && __y_index == 0)
+      return  _VSTD::__unchecked_get<_Iter>(__x.__hold_) ==  _VSTD::__unchecked_get<_I2>(__y.__hold_);
+
+    if (__x_index == 0)
+      return  _VSTD::__unchecked_get<_Iter>(__x.__hold_) == _VSTD::__unchecked_get<_S2>(__y.__hold_);
+
+    return _VSTD::__unchecked_get<_Sent>(__x.__hold_) ==  _VSTD::__unchecked_get<_I2>(__y.__hold_);
+  }
+
+  template<sized_sentinel_for<_Iter> _I2, sized_sentinel_for<_Iter> _S2>
+    requires sized_sentinel_for<_Sent, _I2>
+  friend iter_difference_t<_I2> operator-(const common_iterator& __x, const common_iterator<_I2, _S2>& __y) {
+    _LIBCPP_ASSERT(!__x.__hold_.valueless_by_exception() &&
+                   !__y.__hold_.valueless_by_exception(),
+                   "One or both common_iterators are valueless. (Cannot subtract valueless iterators.)");
+
+    auto __x_index = __x.__hold_.index();
+    auto __y_index = __y.__hold_.index();
+
+    if (__x_index == 1 && __y_index == 1)
+      return 0;
+
+    if (__x_index == 0 && __y_index == 0)
+      return  _VSTD::__unchecked_get<_Iter>(__x.__hold_) - _VSTD::__unchecked_get<_I2>(__y.__hold_);
+
+    if (__x_index == 0)
+      return  _VSTD::__unchecked_get<_Iter>(__x.__hold_) - _VSTD::__unchecked_get<_S2>(__y.__hold_);
+
+    return _VSTD::__unchecked_get<_Sent>(__x.__hold_) - _VSTD::__unchecked_get<_I2>(__y.__hold_);
+  }
+
+  friend iter_rvalue_reference_t<_Iter> iter_move(const common_iterator& __i)
+    noexcept(noexcept(ranges::iter_move(declval<const _Iter&>())))
+      requires input_iterator<_Iter>
+  {
+    _LIBCPP_ASSERT(holds_alternative<_Iter>(__i.__hold_),
+                   "Cannot iter_move a sentinel. Common iterator not holding an iterator.");
+    return ranges::iter_move( _VSTD::__unchecked_get<_Iter>(__i.__hold_));
+  }
+
+  template<indirectly_swappable<_Iter> _I2, class _S2>
+  friend void iter_swap(const common_iterator& __x, const common_iterator<_I2, _S2>& __y)
+      noexcept(noexcept(ranges::iter_swap(declval<const _Iter&>(), declval<const _I2&>())))
+  {
+    _LIBCPP_ASSERT(holds_alternative<_Iter>(__x.__hold_),
+                   "Cannot swap __y with a sentinel. Common iterator (__x) not holding an iterator.");
+    _LIBCPP_ASSERT(holds_alternative<_Iter>(__y.__hold_),
+                   "Cannot swap __x with a sentinel. Common iterator (__y) not holding an iterator.");
+    return ranges::iter_swap( _VSTD::__unchecked_get<_Iter>(__x.__hold_),  _VSTD::__unchecked_get<_Iter>(__y.__hold_));
+  }
+};
+
+template<class _Iter, class _Sent>
+struct incrementable_traits<common_iterator<_Iter, _Sent>> {
+  using difference_type = iter_difference_t<_Iter>;
+};
+
+template<class _Iter>
+concept __denotes_forward_iter =
+  requires { typename iterator_traits<_Iter>::iterator_category; } &&
+  derived_from<typename iterator_traits<_Iter>::iterator_category, forward_iterator_tag>;
+
+template<class _Iter, class _Sent>
+concept __common_iter_has_ptr_op = requires(const common_iterator<_Iter, _Sent>& __a) {
+  __a.operator->();
+};
+
+template<class, class>
+struct __arrow_type_or_void {
+    using type = void;
+};
+
+template<class _Iter, class _Sent>
+  requires __common_iter_has_ptr_op<_Iter, _Sent>
+struct __arrow_type_or_void<_Iter, _Sent> {
+    using type = decltype(declval<const common_iterator<_Iter, _Sent>>().operator->());
+};
+
+template<class _Iter, class _Sent>
+struct iterator_traits<common_iterator<_Iter, _Sent>> {
+  using iterator_concept = _If<forward_iterator<_Iter>,
+                               forward_iterator_tag,
+                               input_iterator_tag>;
+  using iterator_category = _If<__denotes_forward_iter<_Iter>,
+                                forward_iterator_tag,
+                                input_iterator_tag>;
+  using pointer = typename __arrow_type_or_void<_Iter, _Sent>::type;
+  using value_type = iter_value_t<_Iter>;
+  using difference_type = iter_difference_t<_Iter>;
+  using reference = iter_reference_t<_Iter>;
+};
+
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_COMMON_ITERATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/concepts.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/concepts.h
new file mode 100644
index 00000000000..531acdf0a5b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/concepts.h
@@ -0,0 +1,268 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_CONCEPTS_H
+#define _LIBCPP___ITERATOR_CONCEPTS_H
+
+#include <__config>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/iter_move.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/readable_traits.h>
+#include <__memory/pointer_traits.h>
+#include <__utility/forward.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+// clang-format off
+
+// [iterator.concept.readable]
+template<class _In>
+concept __indirectly_readable_impl =
+  requires(const _In __i) {
+    typename iter_value_t<_In>;
+    typename iter_reference_t<_In>;
+    typename iter_rvalue_reference_t<_In>;
+    { *__i } -> same_as<iter_reference_t<_In>>;
+    { ranges::iter_move(__i) } -> same_as<iter_rvalue_reference_t<_In>>;
+  } &&
+  common_reference_with<iter_reference_t<_In>&&, iter_value_t<_In>&> &&
+  common_reference_with<iter_reference_t<_In>&&, iter_rvalue_reference_t<_In>&&> &&
+  common_reference_with<iter_rvalue_reference_t<_In>&&, const iter_value_t<_In>&>;
+
+template<class _In>
+concept indirectly_readable = __indirectly_readable_impl<remove_cvref_t<_In>>;
+
+template<indirectly_readable _Tp>
+using iter_common_reference_t = common_reference_t<iter_reference_t<_Tp>, iter_value_t<_Tp>&>;
+
+// [iterator.concept.writable]
+template<class _Out, class _Tp>
+concept indirectly_writable =
+  requires(_Out&& __o, _Tp&& __t) {
+    *__o = _VSTD::forward<_Tp>(__t);                        // not required to be equality-preserving
+    *_VSTD::forward<_Out>(__o) = _VSTD::forward<_Tp>(__t);  // not required to be equality-preserving
+    const_cast<const iter_reference_t<_Out>&&>(*__o) = _VSTD::forward<_Tp>(__t);                       // not required to be equality-preserving
+    const_cast<const iter_reference_t<_Out>&&>(*_VSTD::forward<_Out>(__o)) = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving
+  };
+
+// [iterator.concept.winc]
+template<class _Tp>
+concept __integer_like = integral<_Tp> && !same_as<_Tp, bool>;
+
+template<class _Tp>
+concept __signed_integer_like = signed_integral<_Tp>;
+
+template<class _Ip>
+concept weakly_incrementable =
+  // TODO: remove this once the clang bug is fixed (bugs.llvm.org/PR48173).
+  !same_as<_Ip, bool> && // Currently, clang does not handle bool correctly.
+  movable<_Ip> &&
+  requires(_Ip __i) {
+    typename iter_difference_t<_Ip>;
+    requires __signed_integer_like<iter_difference_t<_Ip>>;
+    { ++__i } -> same_as<_Ip&>;   // not required to be equality-preserving
+    __i++;                        // not required to be equality-preserving
+  };
+
+// [iterator.concept.inc]
+template<class _Ip>
+concept incrementable =
+  regular<_Ip> &&
+  weakly_incrementable<_Ip> &&
+  requires(_Ip __i) {
+    { __i++ } -> same_as<_Ip>;
+  };
+
+// [iterator.concept.iterator]
+template<class _Ip>
+concept input_or_output_iterator =
+  requires(_Ip __i) {
+    { *__i } -> __referenceable;
+  } &&
+  weakly_incrementable<_Ip>;
+
+// [iterator.concept.sentinel]
+template<class _Sp, class _Ip>
+concept sentinel_for =
+  semiregular<_Sp> &&
+  input_or_output_iterator<_Ip> &&
+  __weakly_equality_comparable_with<_Sp, _Ip>;
+
+template<class, class>
+inline constexpr bool disable_sized_sentinel_for = false;
+
+template<class _Sp, class _Ip>
+concept sized_sentinel_for =
+  sentinel_for<_Sp, _Ip> &&
+  !disable_sized_sentinel_for<remove_cv_t<_Sp>, remove_cv_t<_Ip>> &&
+  requires(const _Ip& __i, const _Sp& __s) {
+    { __s - __i } -> same_as<iter_difference_t<_Ip>>;
+    { __i - __s } -> same_as<iter_difference_t<_Ip>>;
+  };
+
+// [iterator.concept.input]
+template<class _Ip>
+concept input_iterator =
+  input_or_output_iterator<_Ip> &&
+  indirectly_readable<_Ip> &&
+  requires { typename _ITER_CONCEPT<_Ip>; } &&
+  derived_from<_ITER_CONCEPT<_Ip>, input_iterator_tag>;
+
+// [iterator.concept.output]
+template<class _Ip, class _Tp>
+concept output_iterator =
+  input_or_output_iterator<_Ip> &&
+  indirectly_writable<_Ip, _Tp> &&
+  requires (_Ip __it, _Tp&& __t) {
+    *__it++ = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving
+  };
+
+// [iterator.concept.forward]
+template<class _Ip>
+concept forward_iterator =
+  input_iterator<_Ip> &&
+  derived_from<_ITER_CONCEPT<_Ip>, forward_iterator_tag> &&
+  incrementable<_Ip> &&
+  sentinel_for<_Ip, _Ip>;
+
+// [iterator.concept.bidir]
+template<class _Ip>
+concept bidirectional_iterator =
+  forward_iterator<_Ip> &&
+  derived_from<_ITER_CONCEPT<_Ip>, bidirectional_iterator_tag> &&
+  requires(_Ip __i) {
+    { --__i } -> same_as<_Ip&>;
+    { __i-- } -> same_as<_Ip>;
+  };
+
+template<class _Ip>
+concept random_access_iterator =
+  bidirectional_iterator<_Ip> &&
+  derived_from<_ITER_CONCEPT<_Ip>, random_access_iterator_tag> &&
+  totally_ordered<_Ip> &&
+  sized_sentinel_for<_Ip, _Ip> &&
+  requires(_Ip __i, const _Ip __j, const iter_difference_t<_Ip> __n) {
+    { __i += __n } -> same_as<_Ip&>;
+    { __j +  __n } -> same_as<_Ip>;
+    { __n +  __j } -> same_as<_Ip>;
+    { __i -= __n } -> same_as<_Ip&>;
+    { __j -  __n } -> same_as<_Ip>;
+    {  __j[__n]  } -> same_as<iter_reference_t<_Ip>>;
+  };
+
+template<class _Ip>
+concept contiguous_iterator =
+  random_access_iterator<_Ip> &&
+  derived_from<_ITER_CONCEPT<_Ip>, contiguous_iterator_tag> &&
+  is_lvalue_reference_v<iter_reference_t<_Ip>> &&
+  same_as<iter_value_t<_Ip>, remove_cvref_t<iter_reference_t<_Ip>>> &&
+  requires(const _Ip& __i) {
+    { _VSTD::to_address(__i) } -> same_as<add_pointer_t<iter_reference_t<_Ip>>>;
+  };
+
+template<class _Ip>
+concept __has_arrow = input_iterator<_Ip> && (is_pointer_v<_Ip> || requires(_Ip __i) { __i.operator->(); });
+
+// [indirectcallable.indirectinvocable]
+template<class _Fp, class _It>
+concept indirectly_unary_invocable =
+  indirectly_readable<_It> &&
+  copy_constructible<_Fp> &&
+  invocable<_Fp&, iter_value_t<_It>&> &&
+  invocable<_Fp&, iter_reference_t<_It>> &&
+  invocable<_Fp&, iter_common_reference_t<_It>> &&
+  common_reference_with<
+    invoke_result_t<_Fp&, iter_value_t<_It>&>,
+    invoke_result_t<_Fp&, iter_reference_t<_It>>>;
+
+template<class _Fp, class _It>
+concept indirectly_regular_unary_invocable =
+  indirectly_readable<_It> &&
+  copy_constructible<_Fp> &&
+  regular_invocable<_Fp&, iter_value_t<_It>&> &&
+  regular_invocable<_Fp&, iter_reference_t<_It>> &&
+  regular_invocable<_Fp&, iter_common_reference_t<_It>> &&
+  common_reference_with<
+    invoke_result_t<_Fp&, iter_value_t<_It>&>,
+    invoke_result_t<_Fp&, iter_reference_t<_It>>>;
+
+template<class _Fp, class _It>
+concept indirect_unary_predicate =
+  indirectly_readable<_It> &&
+  copy_constructible<_Fp> &&
+  predicate<_Fp&, iter_value_t<_It>&> &&
+  predicate<_Fp&, iter_reference_t<_It>> &&
+  predicate<_Fp&, iter_common_reference_t<_It>>;
+
+template<class _Fp, class _It1, class _It2>
+concept indirect_binary_predicate =
+  indirectly_readable<_It1> && indirectly_readable<_It2> &&
+  copy_constructible<_Fp> &&
+  predicate<_Fp&, iter_value_t<_It1>&, iter_value_t<_It2>&> &&
+  predicate<_Fp&, iter_value_t<_It1>&, iter_reference_t<_It2>> &&
+  predicate<_Fp&, iter_reference_t<_It1>, iter_value_t<_It2>&> &&
+  predicate<_Fp&, iter_reference_t<_It1>, iter_reference_t<_It2>> &&
+  predicate<_Fp&, iter_common_reference_t<_It1>, iter_common_reference_t<_It2>>;
+
+template<class _Fp, class _It1, class _It2 = _It1>
+concept indirect_equivalence_relation =
+  indirectly_readable<_It1> && indirectly_readable<_It2> &&
+  copy_constructible<_Fp> &&
+  equivalence_relation<_Fp&, iter_value_t<_It1>&, iter_value_t<_It2>&> &&
+  equivalence_relation<_Fp&, iter_value_t<_It1>&, iter_reference_t<_It2>> &&
+  equivalence_relation<_Fp&, iter_reference_t<_It1>, iter_value_t<_It2>&> &&
+  equivalence_relation<_Fp&, iter_reference_t<_It1>, iter_reference_t<_It2>> &&
+  equivalence_relation<_Fp&, iter_common_reference_t<_It1>, iter_common_reference_t<_It2>>;
+
+template<class _Fp, class _It1, class _It2 = _It1>
+concept indirect_strict_weak_order =
+  indirectly_readable<_It1> && indirectly_readable<_It2> &&
+  copy_constructible<_Fp> &&
+  strict_weak_order<_Fp&, iter_value_t<_It1>&, iter_value_t<_It2>&> &&
+  strict_weak_order<_Fp&, iter_value_t<_It1>&, iter_reference_t<_It2>> &&
+  strict_weak_order<_Fp&, iter_reference_t<_It1>, iter_value_t<_It2>&> &&
+  strict_weak_order<_Fp&, iter_reference_t<_It1>, iter_reference_t<_It2>> &&
+  strict_weak_order<_Fp&, iter_common_reference_t<_It1>, iter_common_reference_t<_It2>>;
+
+template<class _Fp, class... _Its>
+  requires (indirectly_readable<_Its> && ...) && invocable<_Fp, iter_reference_t<_Its>...>
+using indirect_result_t = invoke_result_t<_Fp, iter_reference_t<_Its>...>;
+
+template<class _In, class _Out>
+concept indirectly_movable =
+  indirectly_readable<_In> &&
+  indirectly_writable<_Out, iter_rvalue_reference_t<_In>>;
+
+template<class _In, class _Out>
+concept indirectly_movable_storable =
+  indirectly_movable<_In, _Out> &&
+  indirectly_writable<_Out, iter_value_t<_In>> &&
+  movable<iter_value_t<_In>> &&
+  constructible_from<iter_value_t<_In>, iter_rvalue_reference_t<_In>> &&
+  assignable_from<iter_value_t<_In>&, iter_rvalue_reference_t<_In>>;
+
+// Note: indirectly_swappable is located in iter_swap.h to prevent a dependency cycle
+// (both iter_swap and indirectly_swappable require indirectly_readable).
+
+// clang-format on
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_CONCEPTS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/counted_iterator.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/counted_iterator.h
new file mode 100644
index 00000000000..55979fe5571
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/counted_iterator.h
@@ -0,0 +1,303 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___ITERATOR_COUNTED_ITERATOR_H
+#define _LIBCPP___ITERATOR_COUNTED_ITERATOR_H
+
+#include <__config>
+#include <__debug>
+#include <__iterator/concepts.h>
+#include <__iterator/default_sentinel.h>
+#include <__iterator/iter_move.h>
+#include <__iterator/iter_swap.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/readable_traits.h>
+#include <__memory/pointer_traits.h>
+#include <__utility/move.h>
+#include <compare>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+template<class>
+struct __counted_iterator_concept {};
+
+template<class _Iter>
+  requires requires { typename _Iter::iterator_concept; }
+struct __counted_iterator_concept<_Iter> {
+  using iterator_concept = typename _Iter::iterator_concept;
+};
+
+template<class>
+struct __counted_iterator_category {};
+
+template<class _Iter>
+  requires requires { typename _Iter::iterator_category; }
+struct __counted_iterator_category<_Iter> {
+  using iterator_category = typename _Iter::iterator_category;
+};
+
+template<class>
+struct __counted_iterator_value_type {};
+
+template<indirectly_readable _Iter>
+struct __counted_iterator_value_type<_Iter> {
+  using value_type = iter_value_t<_Iter>;
+};
+
+template<input_or_output_iterator _Iter>
+class counted_iterator
+  : public __counted_iterator_concept<_Iter>
+  , public __counted_iterator_category<_Iter>
+  , public __counted_iterator_value_type<_Iter>
+{
+public:
+  [[no_unique_address]] _Iter __current_ = _Iter();
+  iter_difference_t<_Iter> __count_ = 0;
+
+  using iterator_type = _Iter;
+  using difference_type = iter_difference_t<_Iter>;
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr counted_iterator() requires default_initializable<_Iter> = default;
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr counted_iterator(_Iter __iter, iter_difference_t<_Iter> __n)
+   : __current_(_VSTD::move(__iter)), __count_(__n) {
+    _LIBCPP_ASSERT(__n >= 0, "__n must not be negative.");
+  }
+
+  template<class _I2>
+    requires convertible_to<const _I2&, _Iter>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr counted_iterator(const counted_iterator<_I2>& __other)
+   : __current_(__other.__current_), __count_(__other.__count_) {}
+
+  template<class _I2>
+    requires assignable_from<_Iter&, const _I2&>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr counted_iterator& operator=(const counted_iterator<_I2>& __other) {
+    __current_ = __other.__current_;
+    __count_ = __other.__count_;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr const _Iter& base() const& { return __current_; }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _Iter base() && { return _VSTD::move(__current_); }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr iter_difference_t<_Iter> count() const noexcept { return __count_; }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr decltype(auto) operator*() {
+    _LIBCPP_ASSERT(__count_ > 0, "Iterator is equal to or past end.");
+    return *__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr decltype(auto) operator*() const
+    requires __dereferenceable<const _Iter>
+  {
+    _LIBCPP_ASSERT(__count_ > 0, "Iterator is equal to or past end.");
+    return *__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto operator->() const noexcept
+    requires contiguous_iterator<_Iter>
+  {
+    return _VSTD::to_address(__current_);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr counted_iterator& operator++() {
+    _LIBCPP_ASSERT(__count_ > 0, "Iterator already at or past end.");
+    ++__current_;
+    --__count_;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  decltype(auto) operator++(int) {
+    _LIBCPP_ASSERT(__count_ > 0, "Iterator already at or past end.");
+    --__count_;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try { return __current_++; }
+    catch(...) { ++__count_; throw; }
+#else
+    return __current_++;
+#endif // _LIBCPP_NO_EXCEPTIONS
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr counted_iterator operator++(int)
+    requires forward_iterator<_Iter>
+  {
+    _LIBCPP_ASSERT(__count_ > 0, "Iterator already at or past end.");
+    counted_iterator __tmp = *this;
+    ++*this;
+    return __tmp;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr counted_iterator& operator--()
+    requires bidirectional_iterator<_Iter>
+  {
+    --__current_;
+    ++__count_;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr counted_iterator operator--(int)
+    requires bidirectional_iterator<_Iter>
+  {
+    counted_iterator __tmp = *this;
+    --*this;
+    return __tmp;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr counted_iterator operator+(iter_difference_t<_Iter> __n) const
+    requires random_access_iterator<_Iter>
+  {
+    return counted_iterator(__current_ + __n, __count_ - __n);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr counted_iterator operator+(
+    iter_difference_t<_Iter> __n, const counted_iterator& __x)
+    requires random_access_iterator<_Iter>
+  {
+    return __x + __n;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr counted_iterator& operator+=(iter_difference_t<_Iter> __n)
+    requires random_access_iterator<_Iter>
+  {
+    _LIBCPP_ASSERT(__n <= __count_, "Cannot advance iterator past end.");
+    __current_ += __n;
+    __count_ -= __n;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr counted_iterator operator-(iter_difference_t<_Iter> __n) const
+    requires random_access_iterator<_Iter>
+  {
+    return counted_iterator(__current_ - __n, __count_ + __n);
+  }
+
+  template<common_with<_Iter> _I2>
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr iter_difference_t<_I2> operator-(
+    const counted_iterator& __lhs, const counted_iterator<_I2>& __rhs)
+  {
+    return __rhs.__count_ - __lhs.__count_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr iter_difference_t<_Iter> operator-(
+    const counted_iterator& __lhs, default_sentinel_t)
+  {
+    return -__lhs.__count_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr iter_difference_t<_Iter> operator-(
+    default_sentinel_t, const counted_iterator& __rhs)
+  {
+    return __rhs.__count_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr counted_iterator& operator-=(iter_difference_t<_Iter> __n)
+    requires random_access_iterator<_Iter>
+  {
+    _LIBCPP_ASSERT(-__n <= __count_, "Attempt to subtract too large of a size: "
+                                     "counted_iterator would be decremented before the "
+                                     "first element of its range.");
+    __current_ -= __n;
+    __count_ += __n;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr decltype(auto) operator[](iter_difference_t<_Iter> __n) const
+    requires random_access_iterator<_Iter>
+  {
+    _LIBCPP_ASSERT(__n < __count_, "Subscript argument must be less than size.");
+    return __current_[__n];
+  }
+
+  template<common_with<_Iter> _I2>
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator==(
+    const counted_iterator& __lhs, const counted_iterator<_I2>& __rhs)
+  {
+    return __lhs.__count_ == __rhs.__count_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator==(
+    const counted_iterator& __lhs, default_sentinel_t)
+  {
+    return __lhs.__count_ == 0;
+  }
+
+  template<common_with<_Iter> _I2>
+  friend constexpr strong_ordering operator<=>(
+    const counted_iterator& __lhs, const counted_iterator<_I2>& __rhs)
+  {
+    return __rhs.__count_ <=> __lhs.__count_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr iter_rvalue_reference_t<_Iter> iter_move(const counted_iterator& __i)
+    noexcept(noexcept(ranges::iter_move(__i.__current_)))
+      requires input_iterator<_Iter>
+  {
+    _LIBCPP_ASSERT(__i.__count_ > 0, "Iterator must not be past end of range.");
+    return ranges::iter_move(__i.__current_);
+  }
+
+  template<indirectly_swappable<_Iter> _I2>
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr void iter_swap(const counted_iterator& __x, const counted_iterator<_I2>& __y)
+    noexcept(noexcept(ranges::iter_swap(__x.__current_, __y.__current_)))
+  {
+    _LIBCPP_ASSERT(__x.__count_ > 0 && __y.__count_ > 0,
+                   "Iterators must not be past end of range.");
+    return ranges::iter_swap(__x.__current_, __y.__current_);
+  }
+};
+
+template<input_iterator _Iter>
+  requires same_as<_ITER_TRAITS<_Iter>, iterator_traits<_Iter>>
+struct iterator_traits<counted_iterator<_Iter>> : iterator_traits<_Iter> {
+  using pointer = conditional_t<contiguous_iterator<_Iter>,
+                                add_pointer_t<iter_reference_t<_Iter>>, void>;
+};
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_COUNTED_ITERATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/data.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/data.h
new file mode 100644
index 00000000000..5e4946cc10b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/data.h
@@ -0,0 +1,51 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_DATA_H
+#define _LIBCPP___ITERATOR_DATA_H
+
+#include <__config>
+#include <cstddef>
+#include <initializer_list>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+template <class _Cont> constexpr
+_LIBCPP_INLINE_VISIBILITY
+auto data(_Cont& __c)
+_NOEXCEPT_(noexcept(__c.data()))
+-> decltype        (__c.data())
+{ return            __c.data(); }
+
+template <class _Cont> constexpr
+_LIBCPP_INLINE_VISIBILITY
+auto data(const _Cont& __c)
+_NOEXCEPT_(noexcept(__c.data()))
+-> decltype        (__c.data())
+{ return            __c.data(); }
+
+template <class _Tp, size_t _Sz>
+_LIBCPP_INLINE_VISIBILITY
+constexpr _Tp* data(_Tp (&__array)[_Sz]) noexcept { return __array; }
+
+template <class _Ep>
+_LIBCPP_INLINE_VISIBILITY
+constexpr const _Ep* data(initializer_list<_Ep> __il) noexcept { return __il.begin(); }
+
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_DATA_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/default_sentinel.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/default_sentinel.h
new file mode 100644
index 00000000000..7172a748feb
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/default_sentinel.h
@@ -0,0 +1,30 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_DEFAULT_SENTINEL_H
+#define _LIBCPP___ITERATOR_DEFAULT_SENTINEL_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+struct default_sentinel_t { };
+inline constexpr default_sentinel_t default_sentinel{};
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_DEFAULT_SENTINEL_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/distance.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/distance.h
new file mode 100644
index 00000000000..70e8e52398f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/distance.h
@@ -0,0 +1,51 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_DISTANCE_H
+#define _LIBCPP___ITERATOR_DISTANCE_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIter>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+typename iterator_traits<_InputIter>::difference_type
+__distance(_InputIter __first, _InputIter __last, input_iterator_tag)
+{
+    typename iterator_traits<_InputIter>::difference_type __r(0);
+    for (; __first != __last; ++__first)
+        ++__r;
+    return __r;
+}
+
+template <class _RandIter>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+typename iterator_traits<_RandIter>::difference_type
+__distance(_RandIter __first, _RandIter __last, random_access_iterator_tag)
+{
+    return __last - __first;
+}
+
+template <class _InputIter>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+typename iterator_traits<_InputIter>::difference_type
+distance(_InputIter __first, _InputIter __last)
+{
+    return _VSTD::__distance(__first, __last, typename iterator_traits<_InputIter>::iterator_category());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_DISTANCE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/empty.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/empty.h
new file mode 100644
index 00000000000..39cd560a276
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/empty.h
@@ -0,0 +1,44 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_EMPTY_H
+#define _LIBCPP___ITERATOR_EMPTY_H
+
+#include <__config>
+#include <cstddef>
+#include <initializer_list>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+template <class _Cont>
+_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+constexpr auto empty(const _Cont& __c)
+_NOEXCEPT_(noexcept(__c.empty()))
+-> decltype        (__c.empty())
+{ return            __c.empty(); }
+
+template <class _Tp, size_t _Sz>
+_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+constexpr bool empty(const _Tp (&)[_Sz]) noexcept { return false; }
+
+template <class _Ep>
+_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+constexpr bool empty(initializer_list<_Ep> __il) noexcept { return __il.size() == 0; }
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_EMPTY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/erase_if_container.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/erase_if_container.h
new file mode 100644
index 00000000000..08f6e224823
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/erase_if_container.h
@@ -0,0 +1,40 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_ERASE_IF_CONTAINER_H
+#define _LIBCPP___ITERATOR_ERASE_IF_CONTAINER_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Container, class _Predicate>
+_LIBCPP_HIDE_FROM_ABI
+typename _Container::size_type
+__libcpp_erase_if_container(_Container& __c, _Predicate& __pred) {
+  typename _Container::size_type __old_size = __c.size();
+
+  const typename _Container::iterator __last = __c.end();
+  for (typename _Container::iterator __iter = __c.begin(); __iter != __last;) {
+    if (__pred(*__iter))
+      __iter = __c.erase(__iter);
+    else
+      ++__iter;
+  }
+
+  return __old_size - __c.size();
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_ERASE_IF_CONTAINER_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/front_insert_iterator.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/front_insert_iterator.h
new file mode 100644
index 00000000000..b229a99f110
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/front_insert_iterator.h
@@ -0,0 +1,70 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_FRONT_INSERT_ITERATOR_H
+#define _LIBCPP___ITERATOR_FRONT_INSERT_ITERATOR_H
+
+#include <__config>
+#include <__iterator/iterator.h>
+#include <__iterator/iterator_traits.h>
+#include <__memory/addressof.h>
+#include <__utility/move.h>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Container>
+class _LIBCPP_TEMPLATE_VIS front_insert_iterator
+#if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
+    : public iterator<output_iterator_tag, void, void, void, void>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+protected:
+    _Container* container;
+public:
+    typedef output_iterator_tag iterator_category;
+    typedef void value_type;
+#if _LIBCPP_STD_VER > 17
+    typedef ptrdiff_t difference_type;
+#else
+    typedef void difference_type;
+#endif
+    typedef void pointer;
+    typedef void reference;
+    typedef _Container container_type;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 explicit front_insert_iterator(_Container& __x) : container(_VSTD::addressof(__x)) {}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 front_insert_iterator& operator=(const typename _Container::value_type& __value_)
+        {container->push_front(__value_); return *this;}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 front_insert_iterator& operator=(typename _Container::value_type&& __value_)
+        {container->push_front(_VSTD::move(__value_)); return *this;}
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 front_insert_iterator& operator*()     {return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 front_insert_iterator& operator++()    {return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 front_insert_iterator  operator++(int) {return *this;}
+};
+
+template <class _Container>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+front_insert_iterator<_Container>
+front_inserter(_Container& __x)
+{
+    return front_insert_iterator<_Container>(__x);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_FRONT_INSERT_ITERATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/incrementable_traits.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/incrementable_traits.h
new file mode 100644
index 00000000000..fd5015ddf1b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/incrementable_traits.h
@@ -0,0 +1,72 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_INCREMENTABLE_TRAITS_H
+#define _LIBCPP___ITERATOR_INCREMENTABLE_TRAITS_H
+
+#include <__config>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+// [incrementable.traits]
+template<class> struct incrementable_traits {};
+
+template<class _Tp>
+requires is_object_v<_Tp>
+struct incrementable_traits<_Tp*> {
+  using difference_type = ptrdiff_t;
+};
+
+template<class _Ip>
+struct incrementable_traits<const _Ip> : incrementable_traits<_Ip> {};
+
+template<class _Tp>
+concept __has_member_difference_type = requires { typename _Tp::difference_type; };
+
+template<__has_member_difference_type _Tp>
+struct incrementable_traits<_Tp> {
+  using difference_type = typename _Tp::difference_type;
+};
+
+template<class _Tp>
+concept __has_integral_minus =
+  requires(const _Tp& __x, const _Tp& __y) {
+    { __x - __y } -> integral;
+  };
+
+template<__has_integral_minus _Tp>
+requires (!__has_member_difference_type<_Tp>)
+struct incrementable_traits<_Tp> {
+  using difference_type = make_signed_t<decltype(declval<_Tp>() - declval<_Tp>())>;
+};
+
+template <class>
+struct iterator_traits;
+
+// Let `RI` be `remove_cvref_t<I>`. The type `iter_difference_t<I>` denotes
+// `incrementable_traits<RI>::difference_type` if `iterator_traits<RI>` names a specialization
+// generated from the primary template, and `iterator_traits<RI>::difference_type` otherwise.
+template <class _Ip>
+using iter_difference_t = typename conditional_t<__is_primary_template<iterator_traits<remove_cvref_t<_Ip> > >::value,
+                                                 incrementable_traits<remove_cvref_t<_Ip> >,
+                                                 iterator_traits<remove_cvref_t<_Ip> > >::difference_type;
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_INCREMENTABLE_TRAITS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/insert_iterator.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/insert_iterator.h
new file mode 100644
index 00000000000..33117419881
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/insert_iterator.h
@@ -0,0 +1,81 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_INSERT_ITERATOR_H
+#define _LIBCPP___ITERATOR_INSERT_ITERATOR_H
+
+#include <__config>
+#include <__iterator/iterator.h>
+#include <__iterator/iterator_traits.h>
+#include <__memory/addressof.h>
+#include <__ranges/access.h>
+#include <__utility/move.h>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+template <class _Container>
+using __insert_iterator_iter_t = ranges::iterator_t<_Container>;
+#else
+template <class _Container>
+using __insert_iterator_iter_t = typename _Container::iterator;
+#endif
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Container>
+class _LIBCPP_TEMPLATE_VIS insert_iterator
+#if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
+    : public iterator<output_iterator_tag, void, void, void, void>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+protected:
+    _Container* container;
+    __insert_iterator_iter_t<_Container> iter;
+public:
+    typedef output_iterator_tag iterator_category;
+    typedef void value_type;
+#if _LIBCPP_STD_VER > 17
+    typedef ptrdiff_t difference_type;
+#else
+    typedef void difference_type;
+#endif
+    typedef void pointer;
+    typedef void reference;
+    typedef _Container container_type;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 insert_iterator(_Container& __x, __insert_iterator_iter_t<_Container> __i)
+        : container(_VSTD::addressof(__x)), iter(__i) {}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 insert_iterator& operator=(const typename _Container::value_type& __value_)
+        {iter = container->insert(iter, __value_); ++iter; return *this;}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 insert_iterator& operator=(typename _Container::value_type&& __value_)
+        {iter = container->insert(iter, _VSTD::move(__value_)); ++iter; return *this;}
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 insert_iterator& operator*()        {return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 insert_iterator& operator++()       {return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 insert_iterator& operator++(int)    {return *this;}
+};
+
+template <class _Container>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+insert_iterator<_Container>
+inserter(_Container& __x, __insert_iterator_iter_t<_Container> __i)
+{
+    return insert_iterator<_Container>(__x, __i);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_INSERT_ITERATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/istream_iterator.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/istream_iterator.h
new file mode 100644
index 00000000000..979d714edf5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/istream_iterator.h
@@ -0,0 +1,92 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_ISTREAM_ITERATOR_H
+#define _LIBCPP___ITERATOR_ISTREAM_ITERATOR_H
+
+#include <__config>
+#include <__iterator/iterator.h>
+#include <__iterator/iterator_traits.h>
+#include <__memory/addressof.h>
+#include <iosfwd> // for forward declarations of char_traits and basic_istream
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp, class _CharT = char,
+          class _Traits = char_traits<_CharT>, class _Distance = ptrdiff_t>
+class _LIBCPP_TEMPLATE_VIS istream_iterator
+#if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
+    : public iterator<input_iterator_tag, _Tp, _Distance, const _Tp*, const _Tp&>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+public:
+    typedef input_iterator_tag iterator_category;
+    typedef _Tp value_type;
+    typedef _Distance difference_type;
+    typedef const _Tp* pointer;
+    typedef const _Tp& reference;
+    typedef _CharT char_type;
+    typedef _Traits traits_type;
+    typedef basic_istream<_CharT,_Traits> istream_type;
+private:
+    istream_type* __in_stream_;
+    _Tp __value_;
+public:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR istream_iterator() : __in_stream_(nullptr), __value_() {}
+    _LIBCPP_INLINE_VISIBILITY istream_iterator(istream_type& __s) : __in_stream_(_VSTD::addressof(__s))
+        {
+            if (!(*__in_stream_ >> __value_))
+                __in_stream_ = nullptr;
+        }
+
+    _LIBCPP_INLINE_VISIBILITY const _Tp& operator*() const {return __value_;}
+    _LIBCPP_INLINE_VISIBILITY const _Tp* operator->() const {return _VSTD::addressof((operator*()));}
+    _LIBCPP_INLINE_VISIBILITY istream_iterator& operator++()
+        {
+            if (!(*__in_stream_ >> __value_))
+                __in_stream_ = nullptr;
+            return *this;
+        }
+    _LIBCPP_INLINE_VISIBILITY istream_iterator  operator++(int)
+        {istream_iterator __t(*this); ++(*this); return __t;}
+
+    template <class _Up, class _CharU, class _TraitsU, class _DistanceU>
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool
+    operator==(const istream_iterator<_Up, _CharU, _TraitsU, _DistanceU>& __x,
+               const istream_iterator<_Up, _CharU, _TraitsU, _DistanceU>& __y);
+};
+
+template <class _Tp, class _CharT, class _Traits, class _Distance>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const istream_iterator<_Tp, _CharT, _Traits, _Distance>& __x,
+           const istream_iterator<_Tp, _CharT, _Traits, _Distance>& __y)
+{
+    return __x.__in_stream_ == __y.__in_stream_;
+}
+
+template <class _Tp, class _CharT, class _Traits, class _Distance>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const istream_iterator<_Tp, _CharT, _Traits, _Distance>& __x,
+           const istream_iterator<_Tp, _CharT, _Traits, _Distance>& __y)
+{
+    return !(__x == __y);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_ISTREAM_ITERATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/istreambuf_iterator.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/istreambuf_iterator.h
new file mode 100644
index 00000000000..0c7676f1690
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/istreambuf_iterator.h
@@ -0,0 +1,105 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_ISTREAMBUF_ITERATOR_H
+#define _LIBCPP___ITERATOR_ISTREAMBUF_ITERATOR_H
+
+#include <__config>
+#include <__iterator/iterator.h>
+#include <__iterator/iterator_traits.h>
+#include <iosfwd> // for forward declaration of basic_streambuf
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template<class _CharT, class _Traits>
+class _LIBCPP_TEMPLATE_VIS istreambuf_iterator
+#if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
+    : public iterator<input_iterator_tag, _CharT,
+                      typename _Traits::off_type, _CharT*,
+                      _CharT>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+public:
+    typedef input_iterator_tag              iterator_category;
+    typedef _CharT                          value_type;
+    typedef typename _Traits::off_type      difference_type;
+    typedef _CharT*                         pointer;
+    typedef _CharT                          reference;
+    typedef _CharT                          char_type;
+    typedef _Traits                         traits_type;
+    typedef typename _Traits::int_type      int_type;
+    typedef basic_streambuf<_CharT,_Traits> streambuf_type;
+    typedef basic_istream<_CharT,_Traits>   istream_type;
+private:
+    mutable streambuf_type* __sbuf_;
+
+    class __proxy
+    {
+        char_type __keep_;
+        streambuf_type* __sbuf_;
+        _LIBCPP_INLINE_VISIBILITY __proxy(char_type __c, streambuf_type* __s)
+            : __keep_(__c), __sbuf_(__s) {}
+        friend class istreambuf_iterator;
+    public:
+        _LIBCPP_INLINE_VISIBILITY char_type operator*() const {return __keep_;}
+    };
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool __test_for_eof() const
+    {
+        if (__sbuf_ && traits_type::eq_int_type(__sbuf_->sgetc(), traits_type::eof()))
+            __sbuf_ = nullptr;
+        return __sbuf_ == nullptr;
+    }
+public:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR istreambuf_iterator() _NOEXCEPT : __sbuf_(nullptr) {}
+    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(istream_type& __s) _NOEXCEPT
+        : __sbuf_(__s.rdbuf()) {}
+    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(streambuf_type* __s) _NOEXCEPT
+        : __sbuf_(__s) {}
+    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(const __proxy& __p) _NOEXCEPT
+        : __sbuf_(__p.__sbuf_) {}
+
+    _LIBCPP_INLINE_VISIBILITY char_type  operator*() const
+        {return static_cast<char_type>(__sbuf_->sgetc());}
+    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator& operator++()
+        {
+            __sbuf_->sbumpc();
+            return *this;
+        }
+    _LIBCPP_INLINE_VISIBILITY __proxy              operator++(int)
+        {
+            return __proxy(__sbuf_->sbumpc(), __sbuf_);
+        }
+
+    _LIBCPP_INLINE_VISIBILITY bool equal(const istreambuf_iterator& __b) const
+        {return __test_for_eof() == __b.__test_for_eof();}
+};
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator==(const istreambuf_iterator<_CharT,_Traits>& __a,
+                const istreambuf_iterator<_CharT,_Traits>& __b)
+                {return __a.equal(__b);}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator!=(const istreambuf_iterator<_CharT,_Traits>& __a,
+                const istreambuf_iterator<_CharT,_Traits>& __b)
+                {return !__a.equal(__b);}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_ISTREAMBUF_ITERATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/iter_move.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/iter_move.h
new file mode 100644
index 00000000000..a2951f764b0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/iter_move.h
@@ -0,0 +1,86 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_ITER_MOVE_H
+#define _LIBCPP___ITERATOR_ITER_MOVE_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__utility/forward.h>
+#include <concepts> // __class_or_enum
+#include <type_traits>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges::__iter_move {
+void iter_move();
+
+template<class _Ip>
+concept __unqualified_iter_move = requires(_Ip&& __i) {
+    iter_move(_VSTD::forward<_Ip>(__i));
+};
+
+// [iterator.cust.move]/1
+// The name ranges::iter_move denotes a customization point object.
+// The expression ranges::iter_move(E) for a subexpression E is
+// expression-equivalent to:
+struct __fn {
+  // [iterator.cust.move]/1.1
+  // iter_move(E), if E has class or enumeration type and iter_move(E) is a
+  // well-formed expression when treated as an unevaluated operand, [...]
+  template<class _Ip>
+    requires __class_or_enum<remove_cvref_t<_Ip>> && __unqualified_iter_move<_Ip>
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator()(_Ip&& __i) const
+    noexcept(noexcept(iter_move(_VSTD::forward<_Ip>(__i))))
+  {
+    return iter_move(_VSTD::forward<_Ip>(__i));
+  }
+
+  // [iterator.cust.move]/1.2
+  // Otherwise, if the expression *E is well-formed:
+  //  1.2.1 if *E is an lvalue, std::move(*E);
+  //  1.2.2 otherwise, *E.
+  template<class _Ip>
+    requires (!(__class_or_enum<remove_cvref_t<_Ip>> && __unqualified_iter_move<_Ip>)) &&
+    requires(_Ip&& __i) { *_VSTD::forward<_Ip>(__i); }
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator()(_Ip&& __i) const
+    noexcept(noexcept(*_VSTD::forward<_Ip>(__i)))
+  {
+    if constexpr (is_lvalue_reference_v<decltype(*_VSTD::forward<_Ip>(__i))>) {
+      return _VSTD::move(*_VSTD::forward<_Ip>(__i));
+    } else {
+      return *_VSTD::forward<_Ip>(__i);
+    }
+  }
+
+  // [iterator.cust.move]/1.3
+  // Otherwise, ranges::iter_move(E) is ill-formed.
+};
+} // namespace ranges::__iter_move
+
+namespace ranges::inline __cpo {
+  inline constexpr auto iter_move = __iter_move::__fn{};
+}
+
+template<__dereferenceable _Tp>
+requires requires(_Tp& __t) { { ranges::iter_move(__t) } -> __referenceable; }
+using iter_rvalue_reference_t = decltype(ranges::iter_move(declval<_Tp&>()));
+
+#endif // !_LIBCPP_HAS_NO_RANGES
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_ITER_MOVE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/iter_swap.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/iter_swap.h
new file mode 100644
index 00000000000..a6c3bc8c663
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/iter_swap.h
@@ -0,0 +1,104 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___ITERATOR_ITER_SWAP_H
+#define _LIBCPP___ITERATOR_ITER_SWAP_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/iter_move.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/readable_traits.h>
+#include <__ranges/access.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+namespace __iter_swap {
+  template<class _I1, class _I2>
+  void iter_swap(_I1, _I2) = delete;
+
+  template<class _T1, class _T2>
+  concept __unqualified_iter_swap = requires(_T1&& __x, _T2&& __y) {
+    iter_swap(_VSTD::forward<_T1>(__x), _VSTD::forward<_T2>(__y));
+  };
+
+  template<class _T1, class _T2>
+  concept __readable_swappable =
+    indirectly_readable<_T1> && indirectly_readable<_T2> &&
+    swappable_with<iter_reference_t<_T1>, iter_reference_t<_T2>>;
+
+  struct __fn {
+    template <class _T1, class _T2>
+      requires __unqualified_iter_swap<_T1, _T2>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void operator()(_T1&& __x, _T2&& __y) const
+      noexcept(noexcept(iter_swap(_VSTD::forward<_T1>(__x), _VSTD::forward<_T2>(__y))))
+    {
+      (void)iter_swap(_VSTD::forward<_T1>(__x), _VSTD::forward<_T2>(__y));
+    }
+
+    template <class _T1, class _T2>
+      requires (!__unqualified_iter_swap<_T1, _T2>) &&
+               __readable_swappable<_T1, _T2>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void operator()(_T1&& __x, _T2&& __y) const
+      noexcept(noexcept(ranges::swap(*_VSTD::forward<_T1>(__x), *_VSTD::forward<_T2>(__y))))
+    {
+      ranges::swap(*_VSTD::forward<_T1>(__x), *_VSTD::forward<_T2>(__y));
+    }
+
+    template <class _T1, class _T2>
+      requires (!__unqualified_iter_swap<_T1, _T2> &&
+                !__readable_swappable<_T1, _T2>) &&
+               indirectly_movable_storable<_T1, _T2> &&
+               indirectly_movable_storable<_T2, _T1>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void operator()(_T1&& __x, _T2&& __y) const
+      noexcept(noexcept(iter_value_t<_T2>(ranges::iter_move(__y))) &&
+               noexcept(*__y = ranges::iter_move(__x)) &&
+               noexcept(*_VSTD::forward<_T1>(__x) = declval<iter_value_t<_T2>>()))
+    {
+      iter_value_t<_T2> __old(ranges::iter_move(__y));
+      *__y = ranges::iter_move(__x);
+      *_VSTD::forward<_T1>(__x) = _VSTD::move(__old);
+    }
+  };
+} // end namespace __iter_swap
+
+inline namespace __cpo {
+  inline constexpr auto iter_swap = __iter_swap::__fn{};
+} // namespace __cpo
+
+} // namespace ranges
+
+template<class _I1, class _I2 = _I1>
+concept indirectly_swappable =
+  indirectly_readable<_I1> && indirectly_readable<_I2> &&
+  requires(const _I1 __i1, const _I2 __i2) {
+    ranges::iter_swap(__i1, __i1);
+    ranges::iter_swap(__i2, __i2);
+    ranges::iter_swap(__i1, __i2);
+    ranges::iter_swap(__i2, __i1);
+  };
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_ITER_SWAP_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/iterator.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/iterator.h
new file mode 100644
index 00000000000..be298ee5228
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/iterator.h
@@ -0,0 +1,35 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_ITERATOR_H
+#define _LIBCPP___ITERATOR_ITERATOR_H
+
+#include <__config>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _Category, class _Tp, class _Distance = ptrdiff_t,
+         class _Pointer = _Tp*, class _Reference = _Tp&>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 iterator
+{
+    typedef _Tp        value_type;
+    typedef _Distance  difference_type;
+    typedef _Pointer   pointer;
+    typedef _Reference reference;
+    typedef _Category  iterator_category;
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_ITERATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/iterator_traits.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/iterator_traits.h
new file mode 100644
index 00000000000..54c3e11e673
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/iterator_traits.h
@@ -0,0 +1,495 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_ITERATOR_TRAITS_H
+#define _LIBCPP___ITERATOR_ITERATOR_TRAITS_H
+
+#include <__config>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/readable_traits.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+template <class _Tp>
+using __with_reference = _Tp&;
+
+template <class _Tp>
+concept __referenceable = requires {
+  typename __with_reference<_Tp>;
+};
+
+template <class _Tp>
+concept __dereferenceable = requires(_Tp& __t) {
+  { *__t } -> __referenceable; // not required to be equality-preserving
+};
+
+// [iterator.traits]
+template<__dereferenceable _Tp>
+using iter_reference_t = decltype(*declval<_Tp&>());
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+template <class _Iter>
+struct _LIBCPP_TEMPLATE_VIS iterator_traits;
+
+struct _LIBCPP_TEMPLATE_VIS input_iterator_tag {};
+struct _LIBCPP_TEMPLATE_VIS output_iterator_tag {};
+struct _LIBCPP_TEMPLATE_VIS forward_iterator_tag       : public input_iterator_tag {};
+struct _LIBCPP_TEMPLATE_VIS bidirectional_iterator_tag : public forward_iterator_tag {};
+struct _LIBCPP_TEMPLATE_VIS random_access_iterator_tag : public bidirectional_iterator_tag {};
+#if _LIBCPP_STD_VER > 17
+struct _LIBCPP_TEMPLATE_VIS contiguous_iterator_tag    : public random_access_iterator_tag {};
+#endif
+
+template <class _Iter>
+struct __iter_traits_cache {
+  using type = _If<
+    __is_primary_template<iterator_traits<_Iter> >::value,
+    _Iter,
+    iterator_traits<_Iter>
+  >;
+};
+template <class _Iter>
+using _ITER_TRAITS = typename __iter_traits_cache<_Iter>::type;
+
+struct __iter_concept_concept_test {
+  template <class _Iter>
+  using _Apply = typename _ITER_TRAITS<_Iter>::iterator_concept;
+};
+struct __iter_concept_category_test {
+  template <class _Iter>
+  using _Apply = typename _ITER_TRAITS<_Iter>::iterator_category;
+};
+struct __iter_concept_random_fallback {
+  template <class _Iter>
+  using _Apply = __enable_if_t<
+                          __is_primary_template<iterator_traits<_Iter> >::value,
+                          random_access_iterator_tag
+                        >;
+};
+
+template <class _Iter, class _Tester> struct __test_iter_concept
+    : _IsValidExpansion<_Tester::template _Apply, _Iter>,
+      _Tester
+{
+};
+
+template <class _Iter>
+struct __iter_concept_cache {
+  using type = _Or<
+    __test_iter_concept<_Iter, __iter_concept_concept_test>,
+    __test_iter_concept<_Iter, __iter_concept_category_test>,
+    __test_iter_concept<_Iter, __iter_concept_random_fallback>
+  >;
+};
+
+template <class _Iter>
+using _ITER_CONCEPT = typename __iter_concept_cache<_Iter>::type::template _Apply<_Iter>;
+
+
+template <class _Tp>
+struct __has_iterator_typedefs
+{
+private:
+    struct __two {char __lx; char __lxx;};
+    template <class _Up> static __two __test(...);
+    template <class _Up> static char __test(typename __void_t<typename _Up::iterator_category>::type* = 0,
+                                            typename __void_t<typename _Up::difference_type>::type* = 0,
+                                            typename __void_t<typename _Up::value_type>::type* = 0,
+                                            typename __void_t<typename _Up::reference>::type* = 0,
+                                            typename __void_t<typename _Up::pointer>::type* = 0);
+public:
+    static const bool value = sizeof(__test<_Tp>(0,0,0,0,0)) == 1;
+};
+
+
+template <class _Tp>
+struct __has_iterator_category
+{
+private:
+    struct __two {char __lx; char __lxx;};
+    template <class _Up> static __two __test(...);
+    template <class _Up> static char __test(typename _Up::iterator_category* = nullptr);
+public:
+    static const bool value = sizeof(__test<_Tp>(nullptr)) == 1;
+};
+
+template <class _Tp>
+struct __has_iterator_concept
+{
+private:
+    struct __two {char __lx; char __lxx;};
+    template <class _Up> static __two __test(...);
+    template <class _Up> static char __test(typename _Up::iterator_concept* = nullptr);
+public:
+    static const bool value = sizeof(__test<_Tp>(nullptr)) == 1;
+};
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+// The `cpp17-*-iterator` exposition-only concepts are easily confused with the Cpp17*Iterator tables,
+// so they've been banished to a namespace that makes it obvious they have a niche use-case.
+namespace __iterator_traits_detail {
+template<class _Ip>
+concept __cpp17_iterator =
+  requires(_Ip __i) {
+    {   *__i } -> __referenceable;
+    {  ++__i } -> same_as<_Ip&>;
+    { *__i++ } -> __referenceable;
+  } &&
+  copyable<_Ip>;
+
+template<class _Ip>
+concept __cpp17_input_iterator =
+  __cpp17_iterator<_Ip> &&
+  equality_comparable<_Ip> &&
+  requires(_Ip __i) {
+    typename incrementable_traits<_Ip>::difference_type;
+    typename indirectly_readable_traits<_Ip>::value_type;
+    typename common_reference_t<iter_reference_t<_Ip>&&,
+                                typename indirectly_readable_traits<_Ip>::value_type&>;
+    typename common_reference_t<decltype(*__i++)&&,
+                                typename indirectly_readable_traits<_Ip>::value_type&>;
+    requires signed_integral<typename incrementable_traits<_Ip>::difference_type>;
+  };
+
+template<class _Ip>
+concept __cpp17_forward_iterator =
+  __cpp17_input_iterator<_Ip> &&
+  constructible_from<_Ip> &&
+  is_lvalue_reference_v<iter_reference_t<_Ip>> &&
+  same_as<remove_cvref_t<iter_reference_t<_Ip>>,
+          typename indirectly_readable_traits<_Ip>::value_type> &&
+  requires(_Ip __i) {
+    {  __i++ } -> convertible_to<_Ip const&>;
+    { *__i++ } -> same_as<iter_reference_t<_Ip>>;
+  };
+
+template<class _Ip>
+concept __cpp17_bidirectional_iterator =
+  __cpp17_forward_iterator<_Ip> &&
+  requires(_Ip __i) {
+    {  --__i } -> same_as<_Ip&>;
+    {  __i-- } -> convertible_to<_Ip const&>;
+    { *__i-- } -> same_as<iter_reference_t<_Ip>>;
+  };
+
+template<class _Ip>
+concept __cpp17_random_access_iterator =
+  __cpp17_bidirectional_iterator<_Ip> &&
+  totally_ordered<_Ip> &&
+  requires(_Ip __i, typename incrementable_traits<_Ip>::difference_type __n) {
+    { __i += __n } -> same_as<_Ip&>;
+    { __i -= __n } -> same_as<_Ip&>;
+    { __i +  __n } -> same_as<_Ip>;
+    { __n +  __i } -> same_as<_Ip>;
+    { __i -  __n } -> same_as<_Ip>;
+    { __i -  __i } -> same_as<decltype(__n)>;
+    {  __i[__n]  } -> convertible_to<iter_reference_t<_Ip>>;
+  };
+} // namespace __iterator_traits_detail
+
+template<class _Ip>
+concept __has_member_reference = requires { typename _Ip::reference; };
+
+template<class _Ip>
+concept __has_member_pointer = requires { typename _Ip::pointer; };
+
+template<class _Ip>
+concept __has_member_iterator_category = requires { typename _Ip::iterator_category; };
+
+template<class _Ip>
+concept __specifies_members = requires {
+    typename _Ip::value_type;
+    typename _Ip::difference_type;
+    requires __has_member_reference<_Ip>;
+    requires __has_member_iterator_category<_Ip>;
+  };
+
+template<class>
+struct __iterator_traits_member_pointer_or_void {
+  using type = void;
+};
+
+template<__has_member_pointer _Tp>
+struct __iterator_traits_member_pointer_or_void<_Tp> {
+  using type = typename _Tp::pointer;
+};
+
+template<class _Tp>
+concept __cpp17_iterator_missing_members =
+  !__specifies_members<_Tp> &&
+  __iterator_traits_detail::__cpp17_iterator<_Tp>;
+
+template<class _Tp>
+concept __cpp17_input_iterator_missing_members =
+  __cpp17_iterator_missing_members<_Tp> &&
+  __iterator_traits_detail::__cpp17_input_iterator<_Tp>;
+
+// Otherwise, `pointer` names `void`.
+template<class>
+struct __iterator_traits_member_pointer_or_arrow_or_void { using type = void; };
+
+// [iterator.traits]/3.2.1
+// If the qualified-id `I::pointer` is valid and denotes a type, `pointer` names that type.
+template<__has_member_pointer _Ip>
+struct __iterator_traits_member_pointer_or_arrow_or_void<_Ip> { using type = typename _Ip::pointer; };
+
+// Otherwise, if `decltype(declval<I&>().operator->())` is well-formed, then `pointer` names that
+// type.
+template<class _Ip>
+  requires requires(_Ip& __i) { __i.operator->(); } && (!__has_member_pointer<_Ip>)
+struct __iterator_traits_member_pointer_or_arrow_or_void<_Ip> {
+  using type = decltype(declval<_Ip&>().operator->());
+};
+
+// Otherwise, `reference` names `iter-reference-t<I>`.
+template<class _Ip>
+struct __iterator_traits_member_reference { using type = iter_reference_t<_Ip>; };
+
+// [iterator.traits]/3.2.2
+// If the qualified-id `I::reference` is valid and denotes a type, `reference` names that type.
+template<__has_member_reference _Ip>
+struct __iterator_traits_member_reference<_Ip> { using type = typename _Ip::reference; };
+
+// [iterator.traits]/3.2.3.4
+// input_iterator_tag
+template<class _Ip>
+struct __deduce_iterator_category {
+  using type = input_iterator_tag;
+};
+
+// [iterator.traits]/3.2.3.1
+// `random_access_iterator_tag` if `I` satisfies `cpp17-random-access-iterator`, or otherwise
+template<__iterator_traits_detail::__cpp17_random_access_iterator _Ip>
+struct __deduce_iterator_category<_Ip> {
+  using type = random_access_iterator_tag;
+};
+
+// [iterator.traits]/3.2.3.2
+// `bidirectional_iterator_tag` if `I` satisfies `cpp17-bidirectional-iterator`, or otherwise
+template<__iterator_traits_detail::__cpp17_bidirectional_iterator _Ip>
+struct __deduce_iterator_category<_Ip> {
+  using type = bidirectional_iterator_tag;
+};
+
+// [iterator.traits]/3.2.3.3
+// `forward_iterator_tag` if `I` satisfies `cpp17-forward-iterator`, or otherwise
+template<__iterator_traits_detail::__cpp17_forward_iterator _Ip>
+struct __deduce_iterator_category<_Ip> {
+  using type = forward_iterator_tag;
+};
+
+template<class _Ip>
+struct __iterator_traits_iterator_category : __deduce_iterator_category<_Ip> {};
+
+// [iterator.traits]/3.2.3
+// If the qualified-id `I::iterator-category` is valid and denotes a type, `iterator-category` names
+// that type.
+template<__has_member_iterator_category _Ip>
+struct __iterator_traits_iterator_category<_Ip> {
+  using type = typename _Ip::iterator_category;
+};
+
+// otherwise, it names void.
+template<class>
+struct __iterator_traits_difference_type { using type = void; };
+
+// If the qualified-id `incrementable_traits<I>::difference_type` is valid and denotes a type, then
+// `difference_type` names that type;
+template<class _Ip>
+requires requires { typename incrementable_traits<_Ip>::difference_type; }
+struct __iterator_traits_difference_type<_Ip> {
+  using type = typename incrementable_traits<_Ip>::difference_type;
+};
+
+// [iterator.traits]/3.4
+// Otherwise, `iterator_traits<I>` has no members by any of the above names.
+template<class>
+struct __iterator_traits {};
+
+// [iterator.traits]/3.1
+// If `I` has valid ([temp.deduct]) member types `difference-type`, `value-type`, `reference`, and
+// `iterator-category`, then `iterator-traits<I>` has the following publicly accessible members:
+template<__specifies_members _Ip>
+struct __iterator_traits<_Ip> {
+  using iterator_category  = typename _Ip::iterator_category;
+  using value_type         = typename _Ip::value_type;
+  using difference_type    = typename _Ip::difference_type;
+  using pointer            = typename __iterator_traits_member_pointer_or_void<_Ip>::type;
+  using reference          = typename _Ip::reference;
+};
+
+// [iterator.traits]/3.2
+// Otherwise, if `I` satisfies the exposition-only concept `cpp17-input-iterator`,
+// `iterator-traits<I>` has the following publicly accessible members:
+template<__cpp17_input_iterator_missing_members _Ip>
+struct __iterator_traits<_Ip> {
+  using iterator_category = typename __iterator_traits_iterator_category<_Ip>::type;
+  using value_type        = typename indirectly_readable_traits<_Ip>::value_type;
+  using difference_type   = typename incrementable_traits<_Ip>::difference_type;
+  using pointer           = typename __iterator_traits_member_pointer_or_arrow_or_void<_Ip>::type;
+  using reference         = typename __iterator_traits_member_reference<_Ip>::type;
+};
+
+// Otherwise, if `I` satisfies the exposition-only concept `cpp17-iterator`, then
+// `iterator_traits<I>` has the following publicly accessible members:
+template<__cpp17_iterator_missing_members _Ip>
+struct __iterator_traits<_Ip> {
+  using iterator_category = output_iterator_tag;
+  using value_type        = void;
+  using difference_type   = typename __iterator_traits_difference_type<_Ip>::type;
+  using pointer           = void;
+  using reference         = void;
+};
+
+template<class _Ip>
+struct iterator_traits : __iterator_traits<_Ip> {
+  using __primary_template = iterator_traits;
+};
+
+#else // !defined(_LIBCPP_HAS_NO_RANGES)
+
+template <class _Iter, bool> struct __iterator_traits {};
+
+template <class _Iter, bool> struct __iterator_traits_impl {};
+
+template <class _Iter>
+struct __iterator_traits_impl<_Iter, true>
+{
+    typedef typename _Iter::difference_type   difference_type;
+    typedef typename _Iter::value_type        value_type;
+    typedef typename _Iter::pointer           pointer;
+    typedef typename _Iter::reference         reference;
+    typedef typename _Iter::iterator_category iterator_category;
+};
+
+template <class _Iter>
+struct __iterator_traits<_Iter, true>
+    :  __iterator_traits_impl
+      <
+        _Iter,
+        is_convertible<typename _Iter::iterator_category, input_iterator_tag>::value ||
+        is_convertible<typename _Iter::iterator_category, output_iterator_tag>::value
+      >
+{};
+
+// iterator_traits<Iterator> will only have the nested types if Iterator::iterator_category
+//    exists.  Else iterator_traits<Iterator> will be an empty class.  This is a
+//    conforming extension which allows some programs to compile and behave as
+//    the client expects instead of failing at compile time.
+
+template <class _Iter>
+struct _LIBCPP_TEMPLATE_VIS iterator_traits
+    : __iterator_traits<_Iter, __has_iterator_typedefs<_Iter>::value> {
+
+  using __primary_template = iterator_traits;
+};
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+template<class _Tp>
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+requires is_object_v<_Tp>
+#endif
+struct _LIBCPP_TEMPLATE_VIS iterator_traits<_Tp*>
+{
+    typedef ptrdiff_t difference_type;
+    typedef typename remove_cv<_Tp>::type value_type;
+    typedef _Tp* pointer;
+    typedef _Tp& reference;
+    typedef random_access_iterator_tag iterator_category;
+#if _LIBCPP_STD_VER > 17
+    typedef contiguous_iterator_tag    iterator_concept;
+#endif
+};
+
+template <class _Tp, class _Up, bool = __has_iterator_category<iterator_traits<_Tp> >::value>
+struct __has_iterator_category_convertible_to
+    : is_convertible<typename iterator_traits<_Tp>::iterator_category, _Up>
+{};
+
+template <class _Tp, class _Up>
+struct __has_iterator_category_convertible_to<_Tp, _Up, false> : false_type {};
+
+template <class _Tp, class _Up, bool = __has_iterator_concept<_Tp>::value>
+struct __has_iterator_concept_convertible_to
+    : is_convertible<typename _Tp::iterator_concept, _Up>
+{};
+
+template <class _Tp, class _Up>
+struct __has_iterator_concept_convertible_to<_Tp, _Up, false> : false_type {};
+
+template <class _Tp>
+struct __is_cpp17_input_iterator : public __has_iterator_category_convertible_to<_Tp, input_iterator_tag> {};
+
+template <class _Tp>
+struct __is_cpp17_forward_iterator : public __has_iterator_category_convertible_to<_Tp, forward_iterator_tag> {};
+
+template <class _Tp>
+struct __is_cpp17_bidirectional_iterator : public __has_iterator_category_convertible_to<_Tp, bidirectional_iterator_tag> {};
+
+template <class _Tp>
+struct __is_cpp17_random_access_iterator : public __has_iterator_category_convertible_to<_Tp, random_access_iterator_tag> {};
+
+// __is_cpp17_contiguous_iterator determines if an iterator is known by
+// libc++ to be contiguous, either because it advertises itself as such
+// (in C++20) or because it is a pointer type or a known trivial wrapper
+// around a (possibly fancy) pointer type, such as __wrap_iter<T*>.
+// Such iterators receive special "contiguous" optimizations in
+// std::copy and std::sort.
+//
+#if _LIBCPP_STD_VER > 17
+template <class _Tp>
+struct __is_cpp17_contiguous_iterator : _Or<
+    __has_iterator_category_convertible_to<_Tp, contiguous_iterator_tag>,
+    __has_iterator_concept_convertible_to<_Tp, contiguous_iterator_tag>
+> {};
+#else
+template <class _Tp>
+struct __is_cpp17_contiguous_iterator : false_type {};
+#endif
+
+// Any native pointer which is an iterator is also a contiguous iterator.
+template <class _Up>
+struct __is_cpp17_contiguous_iterator<_Up*> : true_type {};
+
+
+template <class _Tp>
+struct __is_exactly_cpp17_input_iterator
+    : public integral_constant<bool,
+         __has_iterator_category_convertible_to<_Tp, input_iterator_tag>::value &&
+        !__has_iterator_category_convertible_to<_Tp, forward_iterator_tag>::value> {};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator>
+using __iter_value_type = typename iterator_traits<_InputIterator>::value_type;
+
+template<class _InputIterator>
+using __iter_key_type = remove_const_t<typename iterator_traits<_InputIterator>::value_type::first_type>;
+
+template<class _InputIterator>
+using __iter_mapped_type = typename iterator_traits<_InputIterator>::value_type::second_type;
+
+template<class _InputIterator>
+using __iter_to_alloc_type = pair<
+    add_const_t<typename iterator_traits<_InputIterator>::value_type::first_type>,
+    typename iterator_traits<_InputIterator>::value_type::second_type>;
+#endif // _LIBCPP_STD_VER >= 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_ITERATOR_TRAITS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/move_iterator.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/move_iterator.h
new file mode 100644
index 00000000000..eac9264df30
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/move_iterator.h
@@ -0,0 +1,184 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_MOVE_ITERATOR_H
+#define _LIBCPP___ITERATOR_MOVE_ITERATOR_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Iter>
+class _LIBCPP_TEMPLATE_VIS move_iterator
+{
+private:
+    _Iter __i;
+public:
+    typedef _Iter                                            iterator_type;
+    typedef typename iterator_traits<iterator_type>::value_type value_type;
+    typedef typename iterator_traits<iterator_type>::difference_type difference_type;
+    typedef iterator_type pointer;
+    typedef _If<__is_cpp17_random_access_iterator<_Iter>::value,
+        random_access_iterator_tag,
+        typename iterator_traits<_Iter>::iterator_category>  iterator_category;
+#if _LIBCPP_STD_VER > 17
+    typedef input_iterator_tag                               iterator_concept;
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+    typedef typename iterator_traits<iterator_type>::reference __reference;
+    typedef typename conditional<
+            is_reference<__reference>::value,
+            typename remove_reference<__reference>::type&&,
+            __reference
+        >::type reference;
+#else
+    typedef typename iterator_traits<iterator_type>::reference reference;
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    move_iterator() : __i() {}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    explicit move_iterator(_Iter __x) : __i(__x) {}
+
+    template <class _Up, class = __enable_if_t<
+        !is_same<_Up, _Iter>::value && is_convertible<_Up const&, _Iter>::value
+    > >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    move_iterator(const move_iterator<_Up>& __u) : __i(__u.base()) {}
+
+    template <class _Up, class = __enable_if_t<
+        !is_same<_Up, _Iter>::value &&
+        is_convertible<_Up const&, _Iter>::value &&
+        is_assignable<_Iter&, _Up const&>::value
+    > >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    move_iterator& operator=(const move_iterator<_Up>& __u) {
+        __i = __u.base();
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 _Iter base() const {return __i;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reference operator*() const { return static_cast<reference>(*__i); }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    pointer  operator->() const { return __i;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    move_iterator& operator++() {++__i; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    move_iterator  operator++(int) {move_iterator __tmp(*this); ++__i; return __tmp;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    move_iterator& operator--() {--__i; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    move_iterator  operator--(int) {move_iterator __tmp(*this); --__i; return __tmp;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    move_iterator  operator+ (difference_type __n) const {return move_iterator(__i + __n);}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    move_iterator& operator+=(difference_type __n) {__i += __n; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    move_iterator  operator- (difference_type __n) const {return move_iterator(__i - __n);}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    move_iterator& operator-=(difference_type __n) {__i -= __n; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reference operator[](difference_type __n) const { return static_cast<reference>(__i[__n]); }
+};
+
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+bool
+operator==(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+{
+    return __x.base() == __y.base();
+}
+
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+bool
+operator<(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+{
+    return __x.base() < __y.base();
+}
+
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+bool
+operator!=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+{
+    return __x.base() != __y.base();
+}
+
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+bool
+operator>(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+{
+    return __x.base() > __y.base();
+}
+
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+bool
+operator>=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+{
+    return __x.base() >= __y.base();
+}
+
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+bool
+operator<=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+{
+    return __x.base() <= __y.base();
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+auto
+operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+-> decltype(__x.base() - __y.base())
+{
+    return __x.base() - __y.base();
+}
+#else
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename move_iterator<_Iter1>::difference_type
+operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
+{
+    return __x.base() - __y.base();
+}
+#endif
+
+template <class _Iter>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+move_iterator<_Iter>
+operator+(typename move_iterator<_Iter>::difference_type __n, const move_iterator<_Iter>& __x)
+{
+    return move_iterator<_Iter>(__x.base() + __n);
+}
+
+template <class _Iter>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+move_iterator<_Iter>
+make_move_iterator(_Iter __i)
+{
+    return move_iterator<_Iter>(__i);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_MOVE_ITERATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/next.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/next.h
new file mode 100644
index 00000000000..d764bd6f71f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/next.h
@@ -0,0 +1,82 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_NEXT_H
+#define _LIBCPP___ITERATOR_NEXT_H
+
+#include <__config>
+#include <__debug>
+#include <__function_like.h>
+#include <__iterator/advance.h>
+#include <__iterator/concepts.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIter>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    typename enable_if<__is_cpp17_input_iterator<_InputIter>::value, _InputIter>::type
+    next(_InputIter __x, typename iterator_traits<_InputIter>::difference_type __n = 1) {
+  _LIBCPP_ASSERT(__n >= 0 || __is_cpp17_bidirectional_iterator<_InputIter>::value,
+                 "Attempt to next(it, n) with negative n on a non-bidirectional iterator");
+
+  _VSTD::advance(__x, __n);
+  return __x;
+}
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+struct __next_fn final : private __function_like {
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr explicit __next_fn(__tag __x) noexcept : __function_like(__x) {}
+
+  template <input_or_output_iterator _Ip>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _Ip operator()(_Ip __x) const {
+    ++__x;
+    return __x;
+  }
+
+  template <input_or_output_iterator _Ip>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n) const {
+    ranges::advance(__x, __n);
+    return __x;
+  }
+
+  template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _Ip operator()(_Ip __x, _Sp ___bound) const {
+    ranges::advance(__x, ___bound);
+    return __x;
+  }
+
+  template <input_or_output_iterator _Ip, sentinel_for<_Ip> _Sp>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n, _Sp ___bound) const {
+    ranges::advance(__x, __n, ___bound);
+    return __x;
+  }
+};
+
+inline constexpr auto next = __next_fn(__function_like::__tag());
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_PRIMITIVES_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/ostream_iterator.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/ostream_iterator.h
new file mode 100644
index 00000000000..20a36742cca
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/ostream_iterator.h
@@ -0,0 +1,70 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_OSTREAM_ITERATOR_H
+#define _LIBCPP___ITERATOR_OSTREAM_ITERATOR_H
+
+#include <__config>
+#include <__iterator/iterator.h>
+#include <__iterator/iterator_traits.h>
+#include <__memory/addressof.h>
+#include <iosfwd> // for forward declarations of char_traits and basic_ostream
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp, class _CharT = char, class _Traits = char_traits<_CharT> >
+class _LIBCPP_TEMPLATE_VIS ostream_iterator
+#if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
+    : public iterator<output_iterator_tag, void, void, void, void>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+public:
+    typedef output_iterator_tag             iterator_category;
+    typedef void                            value_type;
+#if _LIBCPP_STD_VER > 17
+    typedef ptrdiff_t                       difference_type;
+#else
+    typedef void                            difference_type;
+#endif
+    typedef void                            pointer;
+    typedef void                            reference;
+    typedef _CharT                          char_type;
+    typedef _Traits                         traits_type;
+    typedef basic_ostream<_CharT, _Traits>  ostream_type;
+
+private:
+    ostream_type* __out_stream_;
+    const char_type* __delim_;
+public:
+    _LIBCPP_INLINE_VISIBILITY ostream_iterator(ostream_type& __s) _NOEXCEPT
+        : __out_stream_(_VSTD::addressof(__s)), __delim_(nullptr) {}
+    _LIBCPP_INLINE_VISIBILITY ostream_iterator(ostream_type& __s, const _CharT* __delimiter) _NOEXCEPT
+        : __out_stream_(_VSTD::addressof(__s)), __delim_(__delimiter) {}
+    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator=(const _Tp& __value_)
+        {
+            *__out_stream_ << __value_;
+            if (__delim_)
+                *__out_stream_ << __delim_;
+            return *this;
+        }
+
+    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator*()     {return *this;}
+    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator++()    {return *this;}
+    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator++(int) {return *this;}
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_OSTREAM_ITERATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/ostreambuf_iterator.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/ostreambuf_iterator.h
new file mode 100644
index 00000000000..3272f6c99d7
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/ostreambuf_iterator.h
@@ -0,0 +1,76 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_OSTREAMBUF_ITERATOR_H
+#define _LIBCPP___ITERATOR_OSTREAMBUF_ITERATOR_H
+
+#include <__config>
+#include <__iterator/iterator.h>
+#include <__iterator/iterator_traits.h>
+#include <iosfwd> // for forward declaration of basic_streambuf
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _CharT, class _Traits>
+class _LIBCPP_TEMPLATE_VIS ostreambuf_iterator
+#if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
+    : public iterator<output_iterator_tag, void, void, void, void>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+public:
+    typedef output_iterator_tag                 iterator_category;
+    typedef void                                value_type;
+#if _LIBCPP_STD_VER > 17
+    typedef ptrdiff_t                           difference_type;
+#else
+    typedef void                                difference_type;
+#endif
+    typedef void                                pointer;
+    typedef void                                reference;
+    typedef _CharT                              char_type;
+    typedef _Traits                             traits_type;
+    typedef basic_streambuf<_CharT, _Traits>    streambuf_type;
+    typedef basic_ostream<_CharT, _Traits>      ostream_type;
+
+private:
+    streambuf_type* __sbuf_;
+public:
+    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator(ostream_type& __s) _NOEXCEPT
+        : __sbuf_(__s.rdbuf()) {}
+    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator(streambuf_type* __s) _NOEXCEPT
+        : __sbuf_(__s) {}
+    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator=(_CharT __c)
+        {
+            if (__sbuf_ && traits_type::eq_int_type(__sbuf_->sputc(__c), traits_type::eof()))
+                __sbuf_ = nullptr;
+            return *this;
+        }
+    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator*()     {return *this;}
+    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator++()    {return *this;}
+    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator++(int) {return *this;}
+    _LIBCPP_INLINE_VISIBILITY bool failed() const _NOEXCEPT {return __sbuf_ == nullptr;}
+
+    template <class _Ch, class _Tr>
+    friend
+    _LIBCPP_HIDDEN
+    ostreambuf_iterator<_Ch, _Tr>
+    __pad_and_output(ostreambuf_iterator<_Ch, _Tr> __s,
+                     const _Ch* __ob, const _Ch* __op, const _Ch* __oe,
+                     ios_base& __iob, _Ch __fl);
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_OSTREAMBUF_ITERATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/prev.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/prev.h
new file mode 100644
index 00000000000..42d836cc1db
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/prev.h
@@ -0,0 +1,74 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_PREV_H
+#define _LIBCPP___ITERATOR_PREV_H
+
+#include <__config>
+#include <__debug>
+#include <__function_like.h>
+#include <__iterator/advance.h>
+#include <__iterator/concepts.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIter>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    typename enable_if<__is_cpp17_input_iterator<_InputIter>::value, _InputIter>::type
+    prev(_InputIter __x, typename iterator_traits<_InputIter>::difference_type __n = 1) {
+  _LIBCPP_ASSERT(__n <= 0 || __is_cpp17_bidirectional_iterator<_InputIter>::value,
+                 "Attempt to prev(it, n) with a positive n on a non-bidirectional iterator");
+  _VSTD::advance(__x, -__n);
+  return __x;
+}
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+struct __prev_fn final : private __function_like {
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr explicit __prev_fn(__tag __x) noexcept : __function_like(__x) {}
+
+  template <bidirectional_iterator _Ip>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _Ip operator()(_Ip __x) const {
+    --__x;
+    return __x;
+  }
+
+  template <bidirectional_iterator _Ip>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n) const {
+    ranges::advance(__x, -__n);
+    return __x;
+  }
+
+  template <bidirectional_iterator _Ip>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _Ip operator()(_Ip __x, iter_difference_t<_Ip> __n, _Ip ___bound) const {
+    ranges::advance(__x, -__n, ___bound);
+    return __x;
+  }
+};
+
+inline constexpr auto prev = __prev_fn(__function_like::__tag());
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_PREV_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/projected.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/projected.h
new file mode 100644
index 00000000000..c24c86b4e06
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/projected.h
@@ -0,0 +1,40 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___ITERATOR_PROJECTED_H
+#define _LIBCPP___ITERATOR_PROJECTED_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/incrementable_traits.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+template<indirectly_readable _It, indirectly_regular_unary_invocable<_It> _Proj>
+struct projected {
+  using value_type = remove_cvref_t<indirect_result_t<_Proj&, _It>>;
+  indirect_result_t<_Proj&, _It> operator*() const; // not defined
+};
+
+template<weakly_incrementable _It, class _Proj>
+struct incrementable_traits<projected<_It, _Proj>> {
+  using difference_type = iter_difference_t<_It>;
+};
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_PROJECTED_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/readable_traits.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/readable_traits.h
new file mode 100644
index 00000000000..90121bea807
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/readable_traits.h
@@ -0,0 +1,86 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_READABLE_TRAITS_H
+#define _LIBCPP___ITERATOR_READABLE_TRAITS_H
+
+#include <__config>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+// [readable.traits]
+template<class> struct __cond_value_type {};
+
+template<class _Tp>
+requires is_object_v<_Tp>
+struct __cond_value_type<_Tp> { using value_type = remove_cv_t<_Tp>; };
+
+template<class _Tp>
+concept __has_member_value_type = requires { typename _Tp::value_type; };
+
+template<class _Tp>
+concept __has_member_element_type = requires { typename _Tp::element_type; };
+
+template<class> struct indirectly_readable_traits {};
+
+template<class _Ip>
+requires is_array_v<_Ip>
+struct indirectly_readable_traits<_Ip> {
+  using value_type = remove_cv_t<remove_extent_t<_Ip>>;
+};
+
+template<class _Ip>
+struct indirectly_readable_traits<const _Ip> : indirectly_readable_traits<_Ip> {};
+
+template<class _Tp>
+struct indirectly_readable_traits<_Tp*> : __cond_value_type<_Tp> {};
+
+template<__has_member_value_type _Tp>
+struct indirectly_readable_traits<_Tp>
+  : __cond_value_type<typename _Tp::value_type> {};
+
+template<__has_member_element_type _Tp>
+struct indirectly_readable_traits<_Tp>
+  : __cond_value_type<typename _Tp::element_type> {};
+
+// Pre-emptively applies LWG3541
+template<__has_member_value_type _Tp>
+requires __has_member_element_type<_Tp>
+struct indirectly_readable_traits<_Tp> {};
+template<__has_member_value_type _Tp>
+requires __has_member_element_type<_Tp> &&
+         same_as<remove_cv_t<typename _Tp::element_type>,
+                 remove_cv_t<typename _Tp::value_type>>
+struct indirectly_readable_traits<_Tp>
+  : __cond_value_type<typename _Tp::value_type> {};
+
+template <class>
+struct iterator_traits;
+
+// Let `RI` be `remove_cvref_t<I>`. The type `iter_value_t<I>` denotes
+// `indirectly_readable_traits<RI>::value_type` if `iterator_traits<RI>` names a specialization
+// generated from the primary template, and `iterator_traits<RI>::value_type` otherwise.
+template <class _Ip>
+using iter_value_t = typename conditional_t<__is_primary_template<iterator_traits<remove_cvref_t<_Ip> > >::value,
+                                            indirectly_readable_traits<remove_cvref_t<_Ip> >,
+                                            iterator_traits<remove_cvref_t<_Ip> > >::value_type;
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_READABLE_TRAITS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/reverse_access.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/reverse_access.h
new file mode 100644
index 00000000000..643aede01c7
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/reverse_access.h
@@ -0,0 +1,104 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_REVERSE_ACCESS_H
+#define _LIBCPP___ITERATOR_REVERSE_ACCESS_H
+
+#include <__config>
+#include <__iterator/reverse_iterator.h>
+#include <cstddef>
+#include <initializer_list>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_CXX03_LANG)
+
+#if _LIBCPP_STD_VER > 11
+
+template <class _Tp, size_t _Np>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+reverse_iterator<_Tp*> rbegin(_Tp (&__array)[_Np])
+{
+    return reverse_iterator<_Tp*>(__array + _Np);
+}
+
+template <class _Tp, size_t _Np>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+reverse_iterator<_Tp*> rend(_Tp (&__array)[_Np])
+{
+    return reverse_iterator<_Tp*>(__array);
+}
+
+template <class _Ep>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+reverse_iterator<const _Ep*> rbegin(initializer_list<_Ep> __il)
+{
+    return reverse_iterator<const _Ep*>(__il.end());
+}
+
+template <class _Ep>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+reverse_iterator<const _Ep*> rend(initializer_list<_Ep> __il)
+{
+    return reverse_iterator<const _Ep*>(__il.begin());
+}
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+auto rbegin(_Cp& __c) -> decltype(__c.rbegin())
+{
+    return __c.rbegin();
+}
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+auto rbegin(const _Cp& __c) -> decltype(__c.rbegin())
+{
+    return __c.rbegin();
+}
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+auto rend(_Cp& __c) -> decltype(__c.rend())
+{
+    return __c.rend();
+}
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+auto rend(const _Cp& __c) -> decltype(__c.rend())
+{
+    return __c.rend();
+}
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+auto crbegin(const _Cp& __c) -> decltype(_VSTD::rbegin(__c))
+{
+    return _VSTD::rbegin(__c);
+}
+
+template <class _Cp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+auto crend(const _Cp& __c) -> decltype(_VSTD::rend(__c))
+{
+    return _VSTD::rend(__c);
+}
+
+#endif
+
+#endif // !defined(_LIBCPP_CXX03_LANG)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_REVERSE_ACCESS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/reverse_iterator.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/reverse_iterator.h
new file mode 100644
index 00000000000..fad9bc175b0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/reverse_iterator.h
@@ -0,0 +1,234 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_REVERSE_ITERATOR_H
+#define _LIBCPP___ITERATOR_REVERSE_ITERATOR_H
+
+#include <__config>
+#include <__iterator/iterator.h>
+#include <__iterator/iterator_traits.h>
+#include <__memory/addressof.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class = void>
+struct __is_stashing_iterator : false_type {};
+
+template <class _Tp>
+struct __is_stashing_iterator<_Tp, typename __void_t<typename _Tp::__stashing_iterator_tag>::type>
+  : true_type {};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Iter>
+class _LIBCPP_TEMPLATE_VIS reverse_iterator
+#if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
+    : public iterator<typename iterator_traits<_Iter>::iterator_category,
+                      typename iterator_traits<_Iter>::value_type,
+                      typename iterator_traits<_Iter>::difference_type,
+                      typename iterator_traits<_Iter>::pointer,
+                      typename iterator_traits<_Iter>::reference>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+private:
+#ifndef _LIBCPP_ABI_NO_ITERATOR_BASES
+    _Iter __t; // no longer used as of LWG #2360, not removed due to ABI break
+#endif
+
+    static_assert(!__is_stashing_iterator<_Iter>::value,
+      "The specified iterator type cannot be used with reverse_iterator; "
+      "Using stashing iterators with reverse_iterator causes undefined behavior");
+
+protected:
+    _Iter current;
+public:
+    typedef _Iter                                            iterator_type;
+    typedef typename iterator_traits<_Iter>::difference_type difference_type;
+    typedef typename iterator_traits<_Iter>::reference       reference;
+    typedef typename iterator_traits<_Iter>::pointer         pointer;
+    typedef _If<__is_cpp17_random_access_iterator<_Iter>::value,
+        random_access_iterator_tag,
+        typename iterator_traits<_Iter>::iterator_category>  iterator_category;
+    typedef typename iterator_traits<_Iter>::value_type      value_type;
+
+#if _LIBCPP_STD_VER > 17
+    typedef _If<__is_cpp17_random_access_iterator<_Iter>::value,
+        random_access_iterator_tag,
+        bidirectional_iterator_tag>                          iterator_concept;
+#endif
+
+#ifndef _LIBCPP_ABI_NO_ITERATOR_BASES
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator() : __t(), current() {}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    explicit reverse_iterator(_Iter __x) : __t(__x), current(__x) {}
+
+    template <class _Up, class = __enable_if_t<
+        !is_same<_Up, _Iter>::value && is_convertible<_Up const&, _Iter>::value
+    > >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator(const reverse_iterator<_Up>& __u)
+        : __t(__u.base()), current(__u.base())
+    { }
+
+    template <class _Up, class = __enable_if_t<
+        !is_same<_Up, _Iter>::value &&
+        is_convertible<_Up const&, _Iter>::value &&
+        is_assignable<_Up const&, _Iter>::value
+    > >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator& operator=(const reverse_iterator<_Up>& __u) {
+        __t = current = __u.base();
+        return *this;
+    }
+#else
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator() : current() {}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    explicit reverse_iterator(_Iter __x) : current(__x) {}
+
+    template <class _Up, class = __enable_if_t<
+        !is_same<_Up, _Iter>::value && is_convertible<_Up const&, _Iter>::value
+    > >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator(const reverse_iterator<_Up>& __u)
+        : current(__u.base())
+    { }
+
+    template <class _Up, class = __enable_if_t<
+        !is_same<_Up, _Iter>::value &&
+        is_convertible<_Up const&, _Iter>::value &&
+        is_assignable<_Up const&, _Iter>::value
+    > >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator& operator=(const reverse_iterator<_Up>& __u) {
+        current = __u.base();
+        return *this;
+    }
+#endif
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    _Iter base() const {return current;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reference operator*() const {_Iter __tmp = current; return *--__tmp;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    pointer  operator->() const {return _VSTD::addressof(operator*());}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator& operator++() {--current; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator  operator++(int) {reverse_iterator __tmp(*this); --current; return __tmp;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator& operator--() {++current; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator  operator--(int) {reverse_iterator __tmp(*this); ++current; return __tmp;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator  operator+ (difference_type __n) const {return reverse_iterator(current - __n);}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator& operator+=(difference_type __n) {current -= __n; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator  operator- (difference_type __n) const {return reverse_iterator(current + __n);}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator& operator-=(difference_type __n) {current += __n; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reference         operator[](difference_type __n) const {return *(*this + __n);}
+};
+
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+bool
+operator==(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
+{
+    return __x.base() == __y.base();
+}
+
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+bool
+operator<(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
+{
+    return __x.base() > __y.base();
+}
+
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+bool
+operator!=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
+{
+    return __x.base() != __y.base();
+}
+
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+bool
+operator>(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
+{
+    return __x.base() < __y.base();
+}
+
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+bool
+operator>=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
+{
+    return __x.base() <= __y.base();
+}
+
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+bool
+operator<=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
+{
+    return __x.base() >= __y.base();
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+auto
+operator-(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
+-> decltype(__y.base() - __x.base())
+{
+    return __y.base() - __x.base();
+}
+#else
+template <class _Iter1, class _Iter2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename reverse_iterator<_Iter1>::difference_type
+operator-(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
+{
+    return __y.base() - __x.base();
+}
+#endif
+
+template <class _Iter>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+reverse_iterator<_Iter>
+operator+(typename reverse_iterator<_Iter>::difference_type __n, const reverse_iterator<_Iter>& __x)
+{
+    return reverse_iterator<_Iter>(__x.base() - __n);
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _Iter>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+reverse_iterator<_Iter> make_reverse_iterator(_Iter __i)
+{
+    return reverse_iterator<_Iter>(__i);
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_REVERSE_ITERATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/size.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/size.h
new file mode 100644
index 00000000000..2e6a7d386cb
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/size.h
@@ -0,0 +1,53 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_SIZE_H
+#define _LIBCPP___ITERATOR_SIZE_H
+
+#include <__config>
+#include <cstddef>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+template <class _Cont>
+_LIBCPP_INLINE_VISIBILITY
+constexpr auto size(const _Cont& __c)
+_NOEXCEPT_(noexcept(__c.size()))
+-> decltype        (__c.size())
+{ return            __c.size(); }
+
+template <class _Tp, size_t _Sz>
+_LIBCPP_INLINE_VISIBILITY
+constexpr size_t size(const _Tp (&)[_Sz]) noexcept { return _Sz; }
+
+#if _LIBCPP_STD_VER > 17
+template <class _Cont>
+_LIBCPP_INLINE_VISIBILITY
+constexpr auto ssize(const _Cont& __c)
+_NOEXCEPT_(noexcept(static_cast<common_type_t<ptrdiff_t, make_signed_t<decltype(__c.size())>>>(__c.size())))
+->                              common_type_t<ptrdiff_t, make_signed_t<decltype(__c.size())>>
+{ return            static_cast<common_type_t<ptrdiff_t, make_signed_t<decltype(__c.size())>>>(__c.size()); }
+
+template <class _Tp, ptrdiff_t _Sz>
+_LIBCPP_INLINE_VISIBILITY
+constexpr ptrdiff_t ssize(const _Tp (&)[_Sz]) noexcept { return _Sz; }
+#endif
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_SIZE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/unreachable_sentinel.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/unreachable_sentinel.h
new file mode 100644
index 00000000000..cbbccd7bb28
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/unreachable_sentinel.h
@@ -0,0 +1,38 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_UNREACHABLE_SENTINEL_H
+#define _LIBCPP___ITERATOR_UNREACHABLE_SENTINEL_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+struct unreachable_sentinel_t {
+  template<weakly_incrementable _Iter>
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator==(unreachable_sentinel_t, const _Iter&) noexcept {
+    return false;
+  }
+};
+
+inline constexpr unreachable_sentinel_t unreachable_sentinel{};
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_UNREACHABLE_SENTINEL_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__iterator/wrap_iter.h b/contrib/libs/cxxsupp/libcxx/include/__iterator/wrap_iter.h
new file mode 100644
index 00000000000..0a978914b1a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__iterator/wrap_iter.h
@@ -0,0 +1,301 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ITERATOR_WRAP_ITER_H
+#define _LIBCPP___ITERATOR_WRAP_ITER_H
+
+#include <__config>
+#include <__debug>
+#include <__iterator/iterator_traits.h>
+#include <__memory/pointer_traits.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Iter>
+class __wrap_iter
+{
+public:
+    typedef _Iter                                                      iterator_type;
+    typedef typename iterator_traits<iterator_type>::value_type        value_type;
+    typedef typename iterator_traits<iterator_type>::difference_type   difference_type;
+    typedef typename iterator_traits<iterator_type>::pointer           pointer;
+    typedef typename iterator_traits<iterator_type>::reference         reference;
+    typedef typename iterator_traits<iterator_type>::iterator_category iterator_category;
+#if _LIBCPP_STD_VER > 17
+    typedef contiguous_iterator_tag                                    iterator_concept;
+#endif
+
+private:
+    iterator_type __i;
+public:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter() _NOEXCEPT
+#if _LIBCPP_STD_VER > 11
+                : __i{}
+#endif
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_i(this);
+#endif
+    }
+    template <class _Up> _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+        __wrap_iter(const __wrap_iter<_Up>& __u,
+            typename enable_if<is_convertible<_Up, iterator_type>::value>::type* = nullptr) _NOEXCEPT
+            : __i(__u.base())
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__iterator_copy(this, &__u);
+#endif
+    }
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+    __wrap_iter(const __wrap_iter& __x)
+        : __i(__x.base())
+    {
+        __get_db()->__iterator_copy(this, &__x);
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+    __wrap_iter& operator=(const __wrap_iter& __x)
+    {
+        if (this != &__x)
+        {
+            __get_db()->__iterator_copy(this, &__x);
+            __i = __x.__i;
+        }
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+    ~__wrap_iter()
+    {
+        __get_db()->__erase_i(this);
+    }
+#endif
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG reference operator*() const _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to dereference a non-dereferenceable iterator");
+#endif
+        return *__i;
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG pointer  operator->() const _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to dereference a non-dereferenceable iterator");
+#endif
+        return _VSTD::__to_address(__i);
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter& operator++() _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to increment a non-incrementable iterator");
+#endif
+        ++__i;
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter  operator++(int) _NOEXCEPT
+        {__wrap_iter __tmp(*this); ++(*this); return __tmp;}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter& operator--() _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__decrementable(this),
+                       "Attempted to decrement a non-decrementable iterator");
+#endif
+        --__i;
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter  operator--(int) _NOEXCEPT
+        {__wrap_iter __tmp(*this); --(*this); return __tmp;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter  operator+ (difference_type __n) const _NOEXCEPT
+        {__wrap_iter __w(*this); __w += __n; return __w;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter& operator+=(difference_type __n) _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__addable(this, __n),
+                   "Attempted to add/subtract an iterator outside its valid range");
+#endif
+        __i += __n;
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter  operator- (difference_type __n) const _NOEXCEPT
+        {return *this + (-__n);}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter& operator-=(difference_type __n) _NOEXCEPT
+        {*this += -__n; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG reference    operator[](difference_type __n) const _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__subscriptable(this, __n),
+                   "Attempted to subscript an iterator outside its valid range");
+#endif
+        return __i[__n];
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG iterator_type base() const _NOEXCEPT {return __i;}
+
+private:
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter(const void* __p, iterator_type __x) : __i(__x)
+    {
+        __get_db()->__insert_ic(this, __p);
+    }
+#else
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter(iterator_type __x) _NOEXCEPT : __i(__x) {}
+#endif
+
+    template <class _Up> friend class __wrap_iter;
+    template <class _CharT, class _Traits, class _Alloc> friend class basic_string;
+    template <class _Tp, class _Alloc> friend class _LIBCPP_TEMPLATE_VIS vector;
+    template <class _Tp, size_t> friend class _LIBCPP_TEMPLATE_VIS span;
+};
+
+template <class _Iter1>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+bool operator==(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT
+{
+    return __x.base() == __y.base();
+}
+
+template <class _Iter1, class _Iter2>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+bool operator==(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
+{
+    return __x.base() == __y.base();
+}
+
+template <class _Iter1>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+bool operator<(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__less_than_comparable(&__x, &__y),
+                   "Attempted to compare incomparable iterators");
+#endif
+    return __x.base() < __y.base();
+}
+
+template <class _Iter1, class _Iter2>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+bool operator<(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__less_than_comparable(&__x, &__y),
+                   "Attempted to compare incomparable iterators");
+#endif
+    return __x.base() < __y.base();
+}
+
+template <class _Iter1>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+bool operator!=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT
+{
+    return !(__x == __y);
+}
+
+template <class _Iter1, class _Iter2>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+bool operator!=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
+{
+    return !(__x == __y);
+}
+
+template <class _Iter1>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+bool operator>(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT
+{
+    return __y < __x;
+}
+
+template <class _Iter1, class _Iter2>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+bool operator>(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
+{
+    return __y < __x;
+}
+
+template <class _Iter1>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+bool operator>=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT
+{
+    return !(__x < __y);
+}
+
+template <class _Iter1, class _Iter2>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+bool operator>=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
+{
+    return !(__x < __y);
+}
+
+template <class _Iter1>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+bool operator<=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT
+{
+    return !(__y < __x);
+}
+
+template <class _Iter1, class _Iter2>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+bool operator<=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
+{
+    return !(__y < __x);
+}
+
+template <class _Iter1, class _Iter2>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+#ifndef _LIBCPP_CXX03_LANG
+auto operator-(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
+    -> decltype(__x.base() - __y.base())
+#else
+typename __wrap_iter<_Iter1>::difference_type
+operator-(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
+#endif // C++03
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__less_than_comparable(&__x, &__y),
+                   "Attempted to subtract incompatible iterators");
+#endif
+    return __x.base() - __y.base();
+}
+
+template <class _Iter1>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
+__wrap_iter<_Iter1> operator+(typename __wrap_iter<_Iter1>::difference_type __n, __wrap_iter<_Iter1> __x) _NOEXCEPT
+{
+    __x += __n;
+    return __x;
+}
+
+#if _LIBCPP_STD_VER <= 17
+template <class _It>
+struct __is_cpp17_contiguous_iterator<__wrap_iter<_It> > : true_type {};
+#endif
+
+template <class _It>
+struct _LIBCPP_TEMPLATE_VIS pointer_traits<__wrap_iter<_It> >
+{
+    typedef __wrap_iter<_It> pointer;
+    typedef typename pointer_traits<_It>::element_type element_type;
+    typedef typename pointer_traits<_It>::difference_type difference_type;
+
+    _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
+    static element_type *to_address(pointer __w) _NOEXCEPT {
+        return _VSTD::__to_address(__w.base());
+    }
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ITERATOR_WRAP_ITER_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__libcpp_version b/contrib/libs/cxxsupp/libcxx/include/__libcpp_version
new file mode 100644
index 00000000000..bfed8193985
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__libcpp_version
@@ -0,0 +1 @@
+14000
diff --git a/contrib/libs/cxxsupp/libcxx/include/__locale b/contrib/libs/cxxsupp/libcxx/include/__locale
new file mode 100644
index 00000000000..38cb7a6f391
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__locale
@@ -0,0 +1,1780 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___LOCALE
+#define _LIBCPP___LOCALE
+
+#include <__availability>
+#include <__config>
+#include <string>
+#include <memory>
+#include <utility>
+#include <mutex>
+#include <cstdint>
+#include <cctype>
+#include <atomic>
+#include <locale.h>
+#if defined(_LIBCPP_MSVCRT_LIKE)
+# include <cstring>
+# include <__support/win32/locale_win32.h>
+#elif defined(_AIX) || defined(__MVS__)
+# include <__support/ibm/xlocale.h>
+#elif defined(__ANDROID__)
+# include <__support/android/locale_bionic.h>
+#elif defined(__sun__)
+# include <xlocale.h>
+# include <__support/solaris/xlocale.h>
+#elif defined(_NEWLIB_VERSION)
+# include <__support/newlib/xlocale.h>
+#elif defined(__OpenBSD__)
+# include <__support/openbsd/xlocale.h>
+#elif (defined(__APPLE__)      || defined(__FreeBSD__) \
+    || defined(__EMSCRIPTEN__) || defined(__IBMCPP__))
+# include <xlocale.h>
+#elif defined(__Fuchsia__)
+# include <__support/fuchsia/xlocale.h>
+#elif defined(__wasi__)
+// WASI libc uses musl's locales support.
+# include <__support/musl/xlocale.h>
+#elif defined(_LIBCPP_HAS_MUSL_LIBC)
+# include <__support/musl/xlocale.h>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_LOCALE__L_EXTENSIONS)
+struct __libcpp_locale_guard {
+  _LIBCPP_INLINE_VISIBILITY
+  __libcpp_locale_guard(locale_t& __loc) : __old_loc_(uselocale(__loc)) {}
+
+  _LIBCPP_INLINE_VISIBILITY
+  ~__libcpp_locale_guard() {
+    if (__old_loc_)
+      uselocale(__old_loc_);
+  }
+
+  locale_t __old_loc_;
+private:
+  __libcpp_locale_guard(__libcpp_locale_guard const&);
+  __libcpp_locale_guard& operator=(__libcpp_locale_guard const&);
+};
+#elif defined(_LIBCPP_MSVCRT_LIKE)
+struct __libcpp_locale_guard {
+    __libcpp_locale_guard(locale_t __l) :
+        __status(_configthreadlocale(_ENABLE_PER_THREAD_LOCALE)) {
+      // Setting the locale can be expensive even when the locale given is
+      // already the current locale, so do an explicit check to see if the
+      // current locale is already the one we want.
+      const char* __lc = __setlocale(nullptr);
+      // If every category is the same, the locale string will simply be the
+      // locale name, otherwise it will be a semicolon-separated string listing
+      // each category.  In the second case, we know at least one category won't
+      // be what we want, so we only have to check the first case.
+      if (_VSTD::strcmp(__l.__get_locale(), __lc) != 0) {
+        __locale_all = _strdup(__lc);
+        if (__locale_all == nullptr)
+          __throw_bad_alloc();
+        __setlocale(__l.__get_locale());
+      }
+    }
+    ~__libcpp_locale_guard() {
+      // The CRT documentation doesn't explicitly say, but setlocale() does the
+      // right thing when given a semicolon-separated list of locale settings
+      // for the different categories in the same format as returned by
+      // setlocale(LC_ALL, nullptr).
+      if (__locale_all != nullptr) {
+        __setlocale(__locale_all);
+        free(__locale_all);
+      }
+      _configthreadlocale(__status);
+    }
+    static const char* __setlocale(const char* __locale) {
+      const char* __new_locale = setlocale(LC_ALL, __locale);
+      if (__new_locale == nullptr)
+        __throw_bad_alloc();
+      return __new_locale;
+    }
+    int __status;
+    char* __locale_all = nullptr;
+};
+#endif
+
+class _LIBCPP_TYPE_VIS locale;
+
+template <class _Facet>
+_LIBCPP_INLINE_VISIBILITY
+bool
+has_facet(const locale&) _NOEXCEPT;
+
+template <class _Facet>
+_LIBCPP_INLINE_VISIBILITY
+const _Facet&
+use_facet(const locale&);
+
+class _LIBCPP_TYPE_VIS locale
+{
+public:
+    // types:
+    class _LIBCPP_TYPE_VIS facet;
+    class _LIBCPP_TYPE_VIS id;
+
+    typedef int category;
+    _LIBCPP_AVAILABILITY_LOCALE_CATEGORY
+    static const category // values assigned here are for exposition only
+        none     = 0,
+        collate  = LC_COLLATE_MASK,
+        ctype    = LC_CTYPE_MASK,
+        monetary = LC_MONETARY_MASK,
+        numeric  = LC_NUMERIC_MASK,
+        time     = LC_TIME_MASK,
+        messages = LC_MESSAGES_MASK,
+        all = collate | ctype | monetary | numeric | time | messages;
+
+    // construct/copy/destroy:
+    locale()  _NOEXCEPT;
+    locale(const locale&)  _NOEXCEPT;
+    explicit locale(const char*);
+    explicit locale(const string&);
+    locale(const locale&, const char*, category);
+    locale(const locale&, const string&, category);
+    template <class _Facet>
+        _LIBCPP_INLINE_VISIBILITY locale(const locale&, _Facet*);
+    locale(const locale&, const locale&, category);
+
+    ~locale();
+
+    const locale& operator=(const locale&)  _NOEXCEPT;
+
+    template <class _Facet>
+      _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+      locale combine(const locale&) const;
+
+    // locale operations:
+    string name() const;
+    bool operator==(const locale&) const;
+    bool operator!=(const locale& __y) const {return !(*this == __y);}
+    template <class _CharT, class _Traits, class _Allocator>
+      _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+      bool operator()(const basic_string<_CharT, _Traits, _Allocator>&,
+                      const basic_string<_CharT, _Traits, _Allocator>&) const;
+
+    // global locale objects:
+    static locale global(const locale&);
+    static const locale& classic();
+
+private:
+    class __imp;
+    __imp* __locale_;
+
+    void __install_ctor(const locale&, facet*, long);
+    static locale& __global();
+    bool has_facet(id&) const;
+    const facet* use_facet(id&) const;
+
+    template <class _Facet> friend bool has_facet(const locale&)  _NOEXCEPT;
+    template <class _Facet> friend const _Facet& use_facet(const locale&);
+};
+
+class _LIBCPP_TYPE_VIS locale::facet
+    : public __shared_count
+{
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit facet(size_t __refs = 0)
+        : __shared_count(static_cast<long>(__refs)-1) {}
+
+    virtual ~facet();
+
+//    facet(const facet&) = delete;     // effectively done in __shared_count
+//    void operator=(const facet&) = delete;
+private:
+    virtual void __on_zero_shared() _NOEXCEPT;
+};
+
+class _LIBCPP_TYPE_VIS locale::id
+{
+    std::atomic<int32_t>        __id_;
+
+    static int32_t __next_id;
+public:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR id() :__id_(0) {}
+private:
+    void operator=(const id&); // = delete;
+    id(const id&); // = delete;
+public:  // only needed for tests
+    long __get();
+
+    friend class locale;
+    friend class locale::__imp;
+};
+
+template <class _Facet>
+inline _LIBCPP_INLINE_VISIBILITY
+locale::locale(const locale& __other, _Facet* __f)
+{
+    __install_ctor(__other, __f, __f ? __f->id.__get() : 0);
+}
+
+template <class _Facet>
+locale
+locale::combine(const locale& __other) const
+{
+    if (!_VSTD::has_facet<_Facet>(__other))
+        __throw_runtime_error("locale::combine: locale missing facet");
+
+    return locale(*this, &const_cast<_Facet&>(_VSTD::use_facet<_Facet>(__other)));
+}
+
+template <class _Facet>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+has_facet(const locale& __l)  _NOEXCEPT
+{
+    return __l.has_facet(_Facet::id);
+}
+
+template <class _Facet>
+inline _LIBCPP_INLINE_VISIBILITY
+const _Facet&
+use_facet(const locale& __l)
+{
+    return static_cast<const _Facet&>(*__l.use_facet(_Facet::id));
+}
+
+// template <class _CharT> class collate;
+
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS collate
+    : public locale::facet
+{
+public:
+    typedef _CharT char_type;
+    typedef basic_string<char_type> string_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit collate(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    int compare(const char_type* __lo1, const char_type* __hi1,
+                const char_type* __lo2, const char_type* __hi2) const
+    {
+        return do_compare(__lo1, __hi1, __lo2, __hi2);
+    }
+
+// Disable double inline warning.
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4141 )
+#endif
+    // FIXME(EricWF): The _LIBCPP_ALWAYS_INLINE is needed on Windows to work
+    // around a dllimport bug that expects an external instantiation.
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_ALWAYS_INLINE
+    string_type transform(const char_type* __lo, const char_type* __hi) const
+    {
+        return do_transform(__lo, __hi);
+    }
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    long hash(const char_type* __lo, const char_type* __hi) const
+    {
+        return do_hash(__lo, __hi);
+    }
+
+    static locale::id id;
+
+protected:
+    ~collate();
+    virtual int do_compare(const char_type* __lo1, const char_type* __hi1,
+                           const char_type* __lo2, const char_type* __hi2) const;
+    virtual string_type do_transform(const char_type* __lo, const char_type* __hi) const
+        {return string_type(__lo, __hi);}
+    virtual long do_hash(const char_type* __lo, const char_type* __hi) const;
+};
+
+template <class _CharT> locale::id collate<_CharT>::id;
+
+template <class _CharT>
+collate<_CharT>::~collate()
+{
+}
+
+template <class _CharT>
+int
+collate<_CharT>::do_compare(const char_type* __lo1, const char_type* __hi1,
+                            const char_type* __lo2, const char_type* __hi2) const
+{
+    for (; __lo2 != __hi2; ++__lo1, ++__lo2)
+    {
+        if (__lo1 == __hi1 || *__lo1 < *__lo2)
+            return -1;
+        if (*__lo2 < *__lo1)
+            return 1;
+    }
+    return __lo1 != __hi1;
+}
+
+template <class _CharT>
+long
+collate<_CharT>::do_hash(const char_type* __lo, const char_type* __hi) const
+{
+    size_t __h = 0;
+    const size_t __sr = __CHAR_BIT__ * sizeof(size_t) - 8;
+    const size_t __mask = size_t(0xF) << (__sr + 4);
+    for(const char_type* __p = __lo; __p != __hi; ++__p)
+    {
+        __h = (__h << 4) + static_cast<size_t>(*__p);
+        size_t __g = __h & __mask;
+        __h ^= __g | (__g >> __sr);
+    }
+    return static_cast<long>(__h);
+}
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS collate<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS collate<wchar_t>)
+#endif
+
+// template <class CharT> class collate_byname;
+
+template <class _CharT> class _LIBCPP_TEMPLATE_VIS collate_byname;
+
+template <>
+class _LIBCPP_TYPE_VIS collate_byname<char>
+    : public collate<char>
+{
+    locale_t __l;
+public:
+    typedef char char_type;
+    typedef basic_string<char_type> string_type;
+
+    explicit collate_byname(const char* __n, size_t __refs = 0);
+    explicit collate_byname(const string& __n, size_t __refs = 0);
+
+protected:
+    ~collate_byname();
+    virtual int do_compare(const char_type* __lo1, const char_type* __hi1,
+                           const char_type* __lo2, const char_type* __hi2) const;
+    virtual string_type do_transform(const char_type* __lo, const char_type* __hi) const;
+};
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+class _LIBCPP_TYPE_VIS collate_byname<wchar_t>
+    : public collate<wchar_t>
+{
+    locale_t __l;
+public:
+    typedef wchar_t char_type;
+    typedef basic_string<char_type> string_type;
+
+    explicit collate_byname(const char* __n, size_t __refs = 0);
+    explicit collate_byname(const string& __n, size_t __refs = 0);
+
+protected:
+    ~collate_byname();
+
+    virtual int do_compare(const char_type* __lo1, const char_type* __hi1,
+                           const char_type* __lo2, const char_type* __hi2) const;
+    virtual string_type do_transform(const char_type* __lo, const char_type* __hi) const;
+};
+#endif
+
+template <class _CharT, class _Traits, class _Allocator>
+bool
+locale::operator()(const basic_string<_CharT, _Traits, _Allocator>& __x,
+                   const basic_string<_CharT, _Traits, _Allocator>& __y) const
+{
+    return _VSTD::use_facet<_VSTD::collate<_CharT> >(*this).compare(
+                                       __x.data(), __x.data() + __x.size(),
+                                       __y.data(), __y.data() + __y.size()) < 0;
+}
+
+// template <class charT> class ctype
+
+class _LIBCPP_TYPE_VIS ctype_base
+{
+public:
+#if defined(_LIBCPP_PROVIDES_DEFAULT_RUNE_TABLE)
+    typedef unsigned long mask;
+    static const mask space  = 1<<0;
+    static const mask print  = 1<<1;
+    static const mask cntrl  = 1<<2;
+    static const mask upper  = 1<<3;
+    static const mask lower  = 1<<4;
+    static const mask alpha  = 1<<5;
+    static const mask digit  = 1<<6;
+    static const mask punct  = 1<<7;
+    static const mask xdigit = 1<<8;
+    static const mask blank  = 1<<9;
+#if defined(__BIONIC__)
+    // Historically this was a part of regex_traits rather than ctype_base. The
+    // historical value of the constant is preserved for ABI compatibility.
+    static const mask __regex_word = 0x8000;
+#else
+    static const mask __regex_word = 1<<10;
+#endif // defined(__BIONIC__)
+#elif defined(__GLIBC__)
+    typedef unsigned short mask;
+    static const mask space  = _ISspace;
+    static const mask print  = _ISprint;
+    static const mask cntrl  = _IScntrl;
+    static const mask upper  = _ISupper;
+    static const mask lower  = _ISlower;
+    static const mask alpha  = _ISalpha;
+    static const mask digit  = _ISdigit;
+    static const mask punct  = _ISpunct;
+    static const mask xdigit = _ISxdigit;
+    static const mask blank  = _ISblank;
+#if defined(__mips__)
+    static const mask __regex_word = static_cast<mask>(_ISbit(15));
+#else
+    static const mask __regex_word = 0x80;
+#endif
+#elif defined(_LIBCPP_MSVCRT_LIKE)
+    typedef unsigned short mask;
+    static const mask space  = _SPACE;
+    static const mask print  = _BLANK|_PUNCT|_ALPHA|_DIGIT;
+    static const mask cntrl  = _CONTROL;
+    static const mask upper  = _UPPER;
+    static const mask lower  = _LOWER;
+    static const mask alpha  = _ALPHA;
+    static const mask digit  = _DIGIT;
+    static const mask punct  = _PUNCT;
+    static const mask xdigit = _HEX;
+    static const mask blank  = _BLANK;
+    static const mask __regex_word = 0x80;
+# define _LIBCPP_CTYPE_MASK_IS_COMPOSITE_PRINT
+#elif defined(__APPLE__) || defined(__FreeBSD__) || defined(__EMSCRIPTEN__) || defined(__NetBSD__)
+# ifdef __APPLE__
+    typedef __uint32_t mask;
+# elif defined(__FreeBSD__)
+    typedef unsigned long mask;
+# elif defined(__EMSCRIPTEN__) || defined(__NetBSD__)
+    typedef unsigned short mask;
+# endif
+    static const mask space  = _CTYPE_S;
+    static const mask print  = _CTYPE_R;
+    static const mask cntrl  = _CTYPE_C;
+    static const mask upper  = _CTYPE_U;
+    static const mask lower  = _CTYPE_L;
+    static const mask alpha  = _CTYPE_A;
+    static const mask digit  = _CTYPE_D;
+    static const mask punct  = _CTYPE_P;
+    static const mask xdigit = _CTYPE_X;
+
+# if defined(__NetBSD__)
+    static const mask blank  = _CTYPE_BL;
+    // NetBSD defines classes up to 0x2000
+    // see sys/ctype_bits.h, _CTYPE_Q
+    static const mask __regex_word = 0x8000;
+# else
+    static const mask blank  = _CTYPE_B;
+    static const mask __regex_word = 0x80;
+# endif
+#elif defined(__sun__) || defined(_AIX)
+    typedef unsigned int mask;
+    static const mask space  = _ISSPACE;
+    static const mask print  = _ISPRINT;
+    static const mask cntrl  = _ISCNTRL;
+    static const mask upper  = _ISUPPER;
+    static const mask lower  = _ISLOWER;
+    static const mask alpha  = _ISALPHA;
+    static const mask digit  = _ISDIGIT;
+    static const mask punct  = _ISPUNCT;
+    static const mask xdigit = _ISXDIGIT;
+    static const mask blank  = _ISBLANK;
+    static const mask __regex_word = 0x80;
+#elif defined(_NEWLIB_VERSION)
+    // Same type as Newlib's _ctype_ array in newlib/libc/include/ctype.h.
+    typedef char mask;
+    static const mask space  = _S;
+    static const mask print  = _P | _U | _L | _N | _B;
+    static const mask cntrl  = _C;
+    static const mask upper  = _U;
+    static const mask lower  = _L;
+    static const mask alpha  = _U | _L;
+    static const mask digit  = _N;
+    static const mask punct  = _P;
+    static const mask xdigit = _X | _N;
+    static const mask blank  = _B;
+    static const mask __regex_word = 0x80;
+# define _LIBCPP_CTYPE_MASK_IS_COMPOSITE_PRINT
+# define _LIBCPP_CTYPE_MASK_IS_COMPOSITE_ALPHA
+# define _LIBCPP_CTYPE_MASK_IS_COMPOSITE_XDIGIT
+#else
+# error unknown rune table for this platform -- do you mean to define _LIBCPP_PROVIDES_DEFAULT_RUNE_TABLE?
+#endif
+    static const mask alnum  = alpha | digit;
+    static const mask graph  = alnum | punct;
+
+    _LIBCPP_INLINE_VISIBILITY ctype_base() {}
+};
+
+template <class _CharT> class _LIBCPP_TEMPLATE_VIS ctype;
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+class _LIBCPP_TYPE_VIS ctype<wchar_t>
+    : public locale::facet,
+      public ctype_base
+{
+public:
+    typedef wchar_t char_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit ctype(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool is(mask __m, char_type __c) const
+    {
+        return do_is(__m, __c);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char_type* is(const char_type* __low, const char_type* __high, mask* __vec) const
+    {
+        return do_is(__low, __high, __vec);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char_type* scan_is(mask __m, const char_type* __low, const char_type* __high) const
+    {
+        return do_scan_is(__m, __low, __high);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char_type* scan_not(mask __m, const char_type* __low, const char_type* __high) const
+    {
+        return do_scan_not(__m, __low, __high);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    char_type toupper(char_type __c) const
+    {
+        return do_toupper(__c);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char_type* toupper(char_type* __low, const char_type* __high) const
+    {
+        return do_toupper(__low, __high);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    char_type tolower(char_type __c) const
+    {
+        return do_tolower(__c);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char_type* tolower(char_type* __low, const char_type* __high) const
+    {
+        return do_tolower(__low, __high);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    char_type widen(char __c) const
+    {
+        return do_widen(__c);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char* widen(const char* __low, const char* __high, char_type* __to) const
+    {
+        return do_widen(__low, __high, __to);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    char narrow(char_type __c, char __dfault) const
+    {
+        return do_narrow(__c, __dfault);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char_type* narrow(const char_type* __low, const char_type* __high, char __dfault, char* __to) const
+    {
+        return do_narrow(__low, __high, __dfault, __to);
+    }
+
+    static locale::id id;
+
+protected:
+    ~ctype();
+    virtual bool do_is(mask __m, char_type __c) const;
+    virtual const char_type* do_is(const char_type* __low, const char_type* __high, mask* __vec) const;
+    virtual const char_type* do_scan_is(mask __m, const char_type* __low, const char_type* __high) const;
+    virtual const char_type* do_scan_not(mask __m, const char_type* __low, const char_type* __high) const;
+    virtual char_type do_toupper(char_type) const;
+    virtual const char_type* do_toupper(char_type* __low, const char_type* __high) const;
+    virtual char_type do_tolower(char_type) const;
+    virtual const char_type* do_tolower(char_type* __low, const char_type* __high) const;
+    virtual char_type do_widen(char) const;
+    virtual const char* do_widen(const char* __low, const char* __high, char_type* __dest) const;
+    virtual char do_narrow(char_type, char __dfault) const;
+    virtual const char_type* do_narrow(const char_type* __low, const char_type* __high, char __dfault, char* __dest) const;
+};
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+template <>
+class _LIBCPP_TYPE_VIS ctype<char>
+    : public locale::facet, public ctype_base
+{
+    const mask* __tab_;
+    bool        __del_;
+public:
+    typedef char char_type;
+
+    explicit ctype(const mask* __tab = nullptr, bool __del = false, size_t __refs = 0);
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool is(mask __m, char_type __c) const
+    {
+        return isascii(__c) ? (__tab_[static_cast<int>(__c)] & __m) !=0 : false;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char_type* is(const char_type* __low, const char_type* __high, mask* __vec) const
+    {
+        for (; __low != __high; ++__low, ++__vec)
+            *__vec = isascii(*__low) ? __tab_[static_cast<int>(*__low)] : 0;
+        return __low;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char_type* scan_is (mask __m, const char_type* __low, const char_type* __high) const
+    {
+        for (; __low != __high; ++__low)
+            if (isascii(*__low) && (__tab_[static_cast<int>(*__low)] & __m))
+                break;
+        return __low;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char_type* scan_not(mask __m, const char_type* __low, const char_type* __high) const
+    {
+        for (; __low != __high; ++__low)
+            if (!(isascii(*__low) && (__tab_[static_cast<int>(*__low)] & __m)))
+                break;
+        return __low;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    char_type toupper(char_type __c) const
+    {
+        return do_toupper(__c);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char_type* toupper(char_type* __low, const char_type* __high) const
+    {
+        return do_toupper(__low, __high);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    char_type tolower(char_type __c) const
+    {
+        return do_tolower(__c);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char_type* tolower(char_type* __low, const char_type* __high) const
+    {
+        return do_tolower(__low, __high);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    char_type widen(char __c) const
+    {
+        return do_widen(__c);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char* widen(const char* __low, const char* __high, char_type* __to) const
+    {
+        return do_widen(__low, __high, __to);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    char narrow(char_type __c, char __dfault) const
+    {
+        return do_narrow(__c, __dfault);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char* narrow(const char_type* __low, const char_type* __high, char __dfault, char* __to) const
+    {
+        return do_narrow(__low, __high, __dfault, __to);
+    }
+
+    static locale::id id;
+
+#ifdef _CACHED_RUNES
+    static const size_t table_size = _CACHED_RUNES;
+#else
+    static const size_t table_size = 256;  // FIXME: Don't hardcode this.
+#endif
+    _LIBCPP_INLINE_VISIBILITY const mask* table() const  _NOEXCEPT {return __tab_;}
+    static const mask* classic_table()  _NOEXCEPT;
+#if defined(__GLIBC__) || defined(__EMSCRIPTEN__)
+    static const int* __classic_upper_table() _NOEXCEPT;
+    static const int* __classic_lower_table() _NOEXCEPT;
+#endif
+#if defined(__NetBSD__)
+    static const short* __classic_upper_table() _NOEXCEPT;
+    static const short* __classic_lower_table() _NOEXCEPT;
+#endif
+
+protected:
+    ~ctype();
+    virtual char_type do_toupper(char_type __c) const;
+    virtual const char_type* do_toupper(char_type* __low, const char_type* __high) const;
+    virtual char_type do_tolower(char_type __c) const;
+    virtual const char_type* do_tolower(char_type* __low, const char_type* __high) const;
+    virtual char_type do_widen(char __c) const;
+    virtual const char* do_widen(const char* __low, const char* __high, char_type* __to) const;
+    virtual char do_narrow(char_type __c, char __dfault) const;
+    virtual const char* do_narrow(const char_type* __low, const char_type* __high, char __dfault, char* __to) const;
+};
+
+// template <class CharT> class ctype_byname;
+
+template <class _CharT> class _LIBCPP_TEMPLATE_VIS ctype_byname;
+
+template <>
+class _LIBCPP_TYPE_VIS ctype_byname<char>
+    : public ctype<char>
+{
+    locale_t __l;
+
+public:
+    explicit ctype_byname(const char*, size_t = 0);
+    explicit ctype_byname(const string&, size_t = 0);
+
+protected:
+    ~ctype_byname();
+    virtual char_type do_toupper(char_type) const;
+    virtual const char_type* do_toupper(char_type* __low, const char_type* __high) const;
+    virtual char_type do_tolower(char_type) const;
+    virtual const char_type* do_tolower(char_type* __low, const char_type* __high) const;
+};
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+class _LIBCPP_TYPE_VIS ctype_byname<wchar_t>
+    : public ctype<wchar_t>
+{
+    locale_t __l;
+
+public:
+    explicit ctype_byname(const char*, size_t = 0);
+    explicit ctype_byname(const string&, size_t = 0);
+
+protected:
+    ~ctype_byname();
+    virtual bool do_is(mask __m, char_type __c) const;
+    virtual const char_type* do_is(const char_type* __low, const char_type* __high, mask* __vec) const;
+    virtual const char_type* do_scan_is(mask __m, const char_type* __low, const char_type* __high) const;
+    virtual const char_type* do_scan_not(mask __m, const char_type* __low, const char_type* __high) const;
+    virtual char_type do_toupper(char_type) const;
+    virtual const char_type* do_toupper(char_type* __low, const char_type* __high) const;
+    virtual char_type do_tolower(char_type) const;
+    virtual const char_type* do_tolower(char_type* __low, const char_type* __high) const;
+    virtual char_type do_widen(char) const;
+    virtual const char* do_widen(const char* __low, const char* __high, char_type* __dest) const;
+    virtual char do_narrow(char_type, char __dfault) const;
+    virtual const char_type* do_narrow(const char_type* __low, const char_type* __high, char __dfault, char* __dest) const;
+};
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+isspace(_CharT __c, const locale& __loc)
+{
+    return use_facet<ctype<_CharT> >(__loc).is(ctype_base::space, __c);
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+isprint(_CharT __c, const locale& __loc)
+{
+    return use_facet<ctype<_CharT> >(__loc).is(ctype_base::print, __c);
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+iscntrl(_CharT __c, const locale& __loc)
+{
+    return use_facet<ctype<_CharT> >(__loc).is(ctype_base::cntrl, __c);
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+isupper(_CharT __c, const locale& __loc)
+{
+    return use_facet<ctype<_CharT> >(__loc).is(ctype_base::upper, __c);
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+islower(_CharT __c, const locale& __loc)
+{
+    return use_facet<ctype<_CharT> >(__loc).is(ctype_base::lower, __c);
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+isalpha(_CharT __c, const locale& __loc)
+{
+    return use_facet<ctype<_CharT> >(__loc).is(ctype_base::alpha, __c);
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+isdigit(_CharT __c, const locale& __loc)
+{
+    return use_facet<ctype<_CharT> >(__loc).is(ctype_base::digit, __c);
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+ispunct(_CharT __c, const locale& __loc)
+{
+    return use_facet<ctype<_CharT> >(__loc).is(ctype_base::punct, __c);
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+isxdigit(_CharT __c, const locale& __loc)
+{
+    return use_facet<ctype<_CharT> >(__loc).is(ctype_base::xdigit, __c);
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+isalnum(_CharT __c, const locale& __loc)
+{
+    return use_facet<ctype<_CharT> >(__loc).is(ctype_base::alnum, __c);
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+isgraph(_CharT __c, const locale& __loc)
+{
+    return use_facet<ctype<_CharT> >(__loc).is(ctype_base::graph, __c);
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+_CharT
+toupper(_CharT __c, const locale& __loc)
+{
+    return use_facet<ctype<_CharT> >(__loc).toupper(__c);
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+_CharT
+tolower(_CharT __c, const locale& __loc)
+{
+    return use_facet<ctype<_CharT> >(__loc).tolower(__c);
+}
+
+// codecvt_base
+
+class _LIBCPP_TYPE_VIS codecvt_base
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY codecvt_base() {}
+    enum result {ok, partial, error, noconv};
+};
+
+// template <class internT, class externT, class stateT> class codecvt;
+
+template <class _InternT, class _ExternT, class _StateT> class _LIBCPP_TEMPLATE_VIS codecvt;
+
+// template <> class codecvt<char, char, mbstate_t>
+
+template <>
+class _LIBCPP_TYPE_VIS codecvt<char, char, mbstate_t>
+    : public locale::facet,
+      public codecvt_base
+{
+public:
+    typedef char      intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const
+    {
+        return do_out(__st, __frm, __frm_end, __frm_nxt, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    result unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const
+    {
+        return do_unshift(__st, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    result in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const
+    {
+        return do_in(__st, __frm, __frm_end, __frm_nxt, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int encoding() const  _NOEXCEPT
+    {
+        return do_encoding();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool always_noconv() const  _NOEXCEPT
+    {
+        return do_always_noconv();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int length(state_type& __st, const extern_type* __frm, const extern_type* __end, size_t __mx) const
+    {
+        return do_length(__st, __frm, __end, __mx);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int max_length() const  _NOEXCEPT
+    {
+        return do_max_length();
+    }
+
+    static locale::id id;
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt(const char*, size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    ~codecvt();
+
+    virtual result do_out(state_type& __st,
+                          const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+                          extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result do_in(state_type& __st,
+                         const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+                         intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result do_unshift(state_type& __st,
+                              extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const  _NOEXCEPT;
+    virtual bool do_always_noconv() const  _NOEXCEPT;
+    virtual int do_length(state_type& __st, const extern_type* __frm, const extern_type* __end, size_t __mx) const;
+    virtual int do_max_length() const  _NOEXCEPT;
+};
+
+// template <> class codecvt<wchar_t, char, mbstate_t>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+class _LIBCPP_TYPE_VIS codecvt<wchar_t, char, mbstate_t>
+    : public locale::facet,
+      public codecvt_base
+{
+    locale_t __l;
+public:
+    typedef wchar_t   intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    explicit codecvt(size_t __refs = 0);
+
+    _LIBCPP_INLINE_VISIBILITY
+    result out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const
+    {
+        return do_out(__st, __frm, __frm_end, __frm_nxt, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    result unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const
+    {
+        return do_unshift(__st, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    result in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const
+    {
+        return do_in(__st, __frm, __frm_end, __frm_nxt, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int encoding() const  _NOEXCEPT
+    {
+        return do_encoding();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool always_noconv() const  _NOEXCEPT
+    {
+        return do_always_noconv();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int length(state_type& __st, const extern_type* __frm, const extern_type* __end, size_t __mx) const
+    {
+        return do_length(__st, __frm, __end, __mx);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int max_length() const  _NOEXCEPT
+    {
+        return do_max_length();
+    }
+
+    static locale::id id;
+
+protected:
+    explicit codecvt(const char*, size_t __refs = 0);
+
+    ~codecvt();
+
+    virtual result do_out(state_type& __st,
+                          const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+                          extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result do_in(state_type& __st,
+                         const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+                         intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result do_unshift(state_type& __st,
+                              extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const  _NOEXCEPT;
+    virtual bool do_always_noconv() const  _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end, size_t __mx) const;
+    virtual int do_max_length() const  _NOEXCEPT;
+};
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// template <> class codecvt<char16_t, char, mbstate_t> // deprecated in C++20
+
+template <>
+class _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_TYPE_VIS codecvt<char16_t, char, mbstate_t>
+    : public locale::facet,
+      public codecvt_base
+{
+public:
+    typedef char16_t  intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const
+    {
+        return do_out(__st, __frm, __frm_end, __frm_nxt, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    result unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const
+    {
+        return do_unshift(__st, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    result in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const
+    {
+        return do_in(__st, __frm, __frm_end, __frm_nxt, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int encoding() const  _NOEXCEPT
+    {
+        return do_encoding();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool always_noconv() const  _NOEXCEPT
+    {
+        return do_always_noconv();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int length(state_type& __st, const extern_type* __frm, const extern_type* __end, size_t __mx) const
+    {
+        return do_length(__st, __frm, __end, __mx);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int max_length() const  _NOEXCEPT
+    {
+        return do_max_length();
+    }
+
+    static locale::id id;
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt(const char*, size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    ~codecvt();
+
+    virtual result do_out(state_type& __st,
+                          const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+                          extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result do_in(state_type& __st,
+                         const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+                         intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result do_unshift(state_type& __st,
+                              extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const  _NOEXCEPT;
+    virtual bool do_always_noconv() const  _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end, size_t __mx) const;
+    virtual int do_max_length() const  _NOEXCEPT;
+};
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+
+// template <> class codecvt<char16_t, char8_t, mbstate_t> // C++20
+
+template <>
+class _LIBCPP_TYPE_VIS codecvt<char16_t, char8_t, mbstate_t>
+    : public locale::facet,
+      public codecvt_base
+{
+public:
+    typedef char16_t  intern_type;
+    typedef char8_t   extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const
+    {
+        return do_out(__st, __frm, __frm_end, __frm_nxt, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    result unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const
+    {
+        return do_unshift(__st, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    result in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const
+    {
+        return do_in(__st, __frm, __frm_end, __frm_nxt, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int encoding() const  _NOEXCEPT
+    {
+        return do_encoding();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool always_noconv() const  _NOEXCEPT
+    {
+        return do_always_noconv();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int length(state_type& __st, const extern_type* __frm, const extern_type* __end, size_t __mx) const
+    {
+        return do_length(__st, __frm, __end, __mx);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int max_length() const  _NOEXCEPT
+    {
+        return do_max_length();
+    }
+
+    static locale::id id;
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt(const char*, size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    ~codecvt();
+
+    virtual result do_out(state_type& __st,
+                          const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+                          extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result do_in(state_type& __st,
+                         const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+                         intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result do_unshift(state_type& __st,
+                              extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const  _NOEXCEPT;
+    virtual bool do_always_noconv() const  _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end, size_t __mx) const;
+    virtual int do_max_length() const  _NOEXCEPT;
+};
+
+#endif
+
+// template <> class codecvt<char32_t, char, mbstate_t> // deprecated in C++20
+
+template <>
+class _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_TYPE_VIS codecvt<char32_t, char, mbstate_t>
+    : public locale::facet,
+      public codecvt_base
+{
+public:
+    typedef char32_t  intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const
+    {
+        return do_out(__st, __frm, __frm_end, __frm_nxt, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    result unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const
+    {
+        return do_unshift(__st, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    result in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const
+    {
+        return do_in(__st, __frm, __frm_end, __frm_nxt, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int encoding() const  _NOEXCEPT
+    {
+        return do_encoding();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool always_noconv() const  _NOEXCEPT
+    {
+        return do_always_noconv();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int length(state_type& __st, const extern_type* __frm, const extern_type* __end, size_t __mx) const
+    {
+        return do_length(__st, __frm, __end, __mx);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int max_length() const  _NOEXCEPT
+    {
+        return do_max_length();
+    }
+
+    static locale::id id;
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt(const char*, size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    ~codecvt();
+
+    virtual result do_out(state_type& __st,
+                          const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+                          extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result do_in(state_type& __st,
+                         const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+                         intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result do_unshift(state_type& __st,
+                              extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const  _NOEXCEPT;
+    virtual bool do_always_noconv() const  _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end, size_t __mx) const;
+    virtual int do_max_length() const  _NOEXCEPT;
+};
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+
+// template <> class codecvt<char32_t, char8_t, mbstate_t> // C++20
+
+template <>
+class _LIBCPP_TYPE_VIS codecvt<char32_t, char8_t, mbstate_t>
+    : public locale::facet,
+      public codecvt_base
+{
+public:
+    typedef char32_t  intern_type;
+    typedef char8_t   extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const
+    {
+        return do_out(__st, __frm, __frm_end, __frm_nxt, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    result unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const
+    {
+        return do_unshift(__st, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    result in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const
+    {
+        return do_in(__st, __frm, __frm_end, __frm_nxt, __to, __to_end, __to_nxt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int encoding() const  _NOEXCEPT
+    {
+        return do_encoding();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool always_noconv() const  _NOEXCEPT
+    {
+        return do_always_noconv();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int length(state_type& __st, const extern_type* __frm, const extern_type* __end, size_t __mx) const
+    {
+        return do_length(__st, __frm, __end, __mx);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int max_length() const  _NOEXCEPT
+    {
+        return do_max_length();
+    }
+
+    static locale::id id;
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt(const char*, size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    ~codecvt();
+
+    virtual result do_out(state_type& __st,
+                          const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+                          extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result do_in(state_type& __st,
+                         const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+                         intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result do_unshift(state_type& __st,
+                              extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const  _NOEXCEPT;
+    virtual bool do_always_noconv() const  _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end, size_t __mx) const;
+    virtual int do_max_length() const  _NOEXCEPT;
+};
+
+#endif
+
+// template <class _InternT, class _ExternT, class _StateT> class codecvt_byname
+
+template <class _InternT, class _ExternT, class _StateT>
+class _LIBCPP_TEMPLATE_VIS codecvt_byname
+    : public codecvt<_InternT, _ExternT, _StateT>
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt_byname(const char* __nm, size_t __refs = 0)
+        : codecvt<_InternT, _ExternT, _StateT>(__nm, __refs) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt_byname(const string& __nm, size_t __refs = 0)
+        : codecvt<_InternT, _ExternT, _StateT>(__nm.c_str(), __refs) {}
+protected:
+    ~codecvt_byname();
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _InternT, class _ExternT, class _StateT>
+codecvt_byname<_InternT, _ExternT, _StateT>::~codecvt_byname()
+{
+}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS codecvt_byname<char, char, mbstate_t>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS codecvt_byname<wchar_t, char, mbstate_t>)
+#endif
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS codecvt_byname<char16_t, char, mbstate_t>) // deprecated in C++20
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS codecvt_byname<char32_t, char, mbstate_t>) // deprecated in C++20
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS codecvt_byname<char16_t, char8_t, mbstate_t>) // C++20
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS codecvt_byname<char32_t, char8_t, mbstate_t>) // C++20
+#endif
+
+template <size_t _Np>
+struct __narrow_to_utf8
+{
+    template <class _OutputIterator, class _CharT>
+    _OutputIterator
+    operator()(_OutputIterator __s, const _CharT* __wb, const _CharT* __we) const;
+};
+
+template <>
+struct __narrow_to_utf8<8>
+{
+    template <class _OutputIterator, class _CharT>
+    _LIBCPP_INLINE_VISIBILITY
+    _OutputIterator
+    operator()(_OutputIterator __s, const _CharT* __wb, const _CharT* __we) const
+    {
+        for (; __wb < __we; ++__wb, ++__s)
+            *__s = *__wb;
+        return __s;
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TYPE_VIS __narrow_to_utf8<16>
+    : public codecvt<char16_t, char, mbstate_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    __narrow_to_utf8() : codecvt<char16_t, char, mbstate_t>(1) {}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+    ~__narrow_to_utf8();
+
+    template <class _OutputIterator, class _CharT>
+    _LIBCPP_INLINE_VISIBILITY
+    _OutputIterator
+    operator()(_OutputIterator __s, const _CharT* __wb, const _CharT* __we) const
+    {
+        result __r = ok;
+        mbstate_t __mb;
+        while (__wb < __we && __r != error)
+        {
+            const int __sz = 32;
+            char __buf[__sz];
+            char* __bn;
+            const char16_t* __wn = (const char16_t*)__wb;
+            __r = do_out(__mb, (const char16_t*)__wb, (const char16_t*)__we, __wn,
+                         __buf, __buf+__sz, __bn);
+            if (__r == codecvt_base::error || __wn == (const char16_t*)__wb)
+                __throw_runtime_error("locale not supported");
+            for (const char* __p = __buf; __p < __bn; ++__p, ++__s)
+                *__s = *__p;
+            __wb = (const _CharT*)__wn;
+        }
+        return __s;
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TYPE_VIS __narrow_to_utf8<32>
+    : public codecvt<char32_t, char, mbstate_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    __narrow_to_utf8() : codecvt<char32_t, char, mbstate_t>(1) {}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+    ~__narrow_to_utf8();
+
+    template <class _OutputIterator, class _CharT>
+    _LIBCPP_INLINE_VISIBILITY
+    _OutputIterator
+    operator()(_OutputIterator __s, const _CharT* __wb, const _CharT* __we) const
+    {
+        result __r = ok;
+        mbstate_t __mb;
+        while (__wb < __we && __r != error)
+        {
+            const int __sz = 32;
+            char __buf[__sz];
+            char* __bn;
+            const char32_t* __wn = (const char32_t*)__wb;
+            __r = do_out(__mb, (const char32_t*)__wb, (const char32_t*)__we, __wn,
+                         __buf, __buf+__sz, __bn);
+            if (__r == codecvt_base::error || __wn == (const char32_t*)__wb)
+                __throw_runtime_error("locale not supported");
+            for (const char* __p = __buf; __p < __bn; ++__p, ++__s)
+                *__s = *__p;
+            __wb = (const _CharT*)__wn;
+        }
+        return __s;
+    }
+};
+
+template <size_t _Np>
+struct __widen_from_utf8
+{
+    template <class _OutputIterator>
+    _OutputIterator
+    operator()(_OutputIterator __s, const char* __nb, const char* __ne) const;
+};
+
+template <>
+struct __widen_from_utf8<8>
+{
+    template <class _OutputIterator>
+    _LIBCPP_INLINE_VISIBILITY
+    _OutputIterator
+    operator()(_OutputIterator __s, const char* __nb, const char* __ne) const
+    {
+        for (; __nb < __ne; ++__nb, ++__s)
+            *__s = *__nb;
+        return __s;
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TYPE_VIS __widen_from_utf8<16>
+    : public codecvt<char16_t, char, mbstate_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    __widen_from_utf8() : codecvt<char16_t, char, mbstate_t>(1) {}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+    ~__widen_from_utf8();
+
+    template <class _OutputIterator>
+    _LIBCPP_INLINE_VISIBILITY
+    _OutputIterator
+    operator()(_OutputIterator __s, const char* __nb, const char* __ne) const
+    {
+        result __r = ok;
+        mbstate_t __mb;
+        while (__nb < __ne && __r != error)
+        {
+            const int __sz = 32;
+            char16_t __buf[__sz];
+            char16_t* __bn;
+            const char* __nn = __nb;
+            __r = do_in(__mb, __nb, __ne - __nb > __sz ? __nb+__sz : __ne, __nn,
+                        __buf, __buf+__sz, __bn);
+            if (__r == codecvt_base::error || __nn == __nb)
+                __throw_runtime_error("locale not supported");
+            for (const char16_t* __p = __buf; __p < __bn; ++__p, ++__s)
+                *__s = *__p;
+            __nb = __nn;
+        }
+        return __s;
+    }
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+struct _LIBCPP_TYPE_VIS __widen_from_utf8<32>
+    : public codecvt<char32_t, char, mbstate_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    __widen_from_utf8() : codecvt<char32_t, char, mbstate_t>(1) {}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+    ~__widen_from_utf8();
+
+    template <class _OutputIterator>
+    _LIBCPP_INLINE_VISIBILITY
+    _OutputIterator
+    operator()(_OutputIterator __s, const char* __nb, const char* __ne) const
+    {
+        result __r = ok;
+        mbstate_t __mb;
+        while (__nb < __ne && __r != error)
+        {
+            const int __sz = 32;
+            char32_t __buf[__sz];
+            char32_t* __bn;
+            const char* __nn = __nb;
+            __r = do_in(__mb, __nb, __ne - __nb > __sz ? __nb+__sz : __ne, __nn,
+                        __buf, __buf+__sz, __bn);
+            if (__r == codecvt_base::error || __nn == __nb)
+                __throw_runtime_error("locale not supported");
+            for (const char32_t* __p = __buf; __p < __bn; ++__p, ++__s)
+                *__s = *__p;
+            __nb = __nn;
+        }
+        return __s;
+    }
+};
+
+// template <class charT> class numpunct
+
+template <class _CharT> class _LIBCPP_TEMPLATE_VIS numpunct;
+
+template <>
+class _LIBCPP_TYPE_VIS numpunct<char>
+    : public locale::facet
+{
+public:
+    typedef char char_type;
+    typedef basic_string<char_type> string_type;
+
+    explicit numpunct(size_t __refs = 0);
+
+    _LIBCPP_INLINE_VISIBILITY char_type decimal_point() const {return do_decimal_point();}
+    _LIBCPP_INLINE_VISIBILITY char_type thousands_sep() const {return do_thousands_sep();}
+    _LIBCPP_INLINE_VISIBILITY string grouping() const         {return do_grouping();}
+    _LIBCPP_INLINE_VISIBILITY string_type truename() const    {return do_truename();}
+    _LIBCPP_INLINE_VISIBILITY string_type falsename() const   {return do_falsename();}
+
+    static locale::id id;
+
+protected:
+    ~numpunct();
+    virtual char_type do_decimal_point() const;
+    virtual char_type do_thousands_sep() const;
+    virtual string do_grouping() const;
+    virtual string_type do_truename() const;
+    virtual string_type do_falsename() const;
+
+    char_type __decimal_point_;
+    char_type __thousands_sep_;
+    string __grouping_;
+};
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+class _LIBCPP_TYPE_VIS numpunct<wchar_t>
+    : public locale::facet
+{
+public:
+    typedef wchar_t char_type;
+    typedef basic_string<char_type> string_type;
+
+    explicit numpunct(size_t __refs = 0);
+
+    _LIBCPP_INLINE_VISIBILITY char_type decimal_point() const {return do_decimal_point();}
+    _LIBCPP_INLINE_VISIBILITY char_type thousands_sep() const {return do_thousands_sep();}
+    _LIBCPP_INLINE_VISIBILITY string grouping() const         {return do_grouping();}
+    _LIBCPP_INLINE_VISIBILITY string_type truename() const    {return do_truename();}
+    _LIBCPP_INLINE_VISIBILITY string_type falsename() const   {return do_falsename();}
+
+    static locale::id id;
+
+protected:
+    ~numpunct();
+    virtual char_type do_decimal_point() const;
+    virtual char_type do_thousands_sep() const;
+    virtual string do_grouping() const;
+    virtual string_type do_truename() const;
+    virtual string_type do_falsename() const;
+
+    char_type __decimal_point_;
+    char_type __thousands_sep_;
+    string __grouping_;
+};
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// template <class charT> class numpunct_byname
+
+template <class _CharT> class _LIBCPP_TEMPLATE_VIS numpunct_byname;
+
+template <>
+class _LIBCPP_TYPE_VIS numpunct_byname<char>
+: public numpunct<char>
+{
+public:
+    typedef char char_type;
+    typedef basic_string<char_type> string_type;
+
+    explicit numpunct_byname(const char* __nm, size_t __refs = 0);
+    explicit numpunct_byname(const string& __nm, size_t __refs = 0);
+
+protected:
+    ~numpunct_byname();
+
+private:
+    void __init(const char*);
+};
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+class _LIBCPP_TYPE_VIS numpunct_byname<wchar_t>
+: public numpunct<wchar_t>
+{
+public:
+    typedef wchar_t char_type;
+    typedef basic_string<char_type> string_type;
+
+    explicit numpunct_byname(const char* __nm, size_t __refs = 0);
+    explicit numpunct_byname(const string& __nm, size_t __refs = 0);
+
+protected:
+    ~numpunct_byname();
+
+private:
+    void __init(const char*);
+};
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___LOCALE
diff --git a/contrib/libs/cxxsupp/libcxx/include/__mbstate_t.h b/contrib/libs/cxxsupp/libcxx/include/__mbstate_t.h
new file mode 100644
index 00000000000..3489f9cc0e3
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__mbstate_t.h
@@ -0,0 +1,44 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MBSTATE_T_H
+#define _LIBCPP___MBSTATE_T_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+// TODO(ldionne):
+// The goal of this header is to provide mbstate_t without having to pull in
+// <wchar.h> or <uchar.h>. This is necessary because we need that type even
+// when we don't have (or try to provide) support for wchar_t, because several
+// types like std::fpos are defined in terms of mbstate_t.
+//
+// This is a gruesome hack, but I don't know how to make it cleaner for
+// the time being.
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#   include <wchar.h> // for mbstate_t
+#elif __has_include(<bits/types/mbstate_t.h>)
+#   include <bits/types/mbstate_t.h> // works on most Unixes
+#elif __has_include(<sys/_types/_mbstate_t.h>)
+#   include <sys/_types/_mbstate_t.h> // works on Darwin
+#else
+#   error "The library was configured without support for wide-characters, but we don't know how to get the definition of mbstate_t without <wchar.h> on your platform."
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::mbstate_t _LIBCPP_USING_IF_EXISTS;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MBSTATE_T_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/addressof.h b/contrib/libs/cxxsupp/libcxx/include/__memory/addressof.h
new file mode 100644
index 00000000000..c45dedfaec9
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/addressof.h
@@ -0,0 +1,76 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_ADDRESSOF_H
+#define _LIBCPP___MEMORY_ADDRESSOF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+_LIBCPP_NO_CFI _LIBCPP_INLINE_VISIBILITY
+_Tp*
+addressof(_Tp& __x) _NOEXCEPT
+{
+    return __builtin_addressof(__x);
+}
+
+#if defined(_LIBCPP_HAS_OBJC_ARC) && !defined(_LIBCPP_PREDEFINED_OBJC_ARC_ADDRESSOF)
+// Objective-C++ Automatic Reference Counting uses qualified pointers
+// that require special addressof() signatures. When
+// _LIBCPP_PREDEFINED_OBJC_ARC_ADDRESSOF is defined, the compiler
+// itself is providing these definitions. Otherwise, we provide them.
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+__strong _Tp*
+addressof(__strong _Tp& __x) _NOEXCEPT
+{
+  return &__x;
+}
+
+#ifdef _LIBCPP_HAS_OBJC_ARC_WEAK
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+__weak _Tp*
+addressof(__weak _Tp& __x) _NOEXCEPT
+{
+  return &__x;
+}
+#endif
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+__autoreleasing _Tp*
+addressof(__autoreleasing _Tp& __x) _NOEXCEPT
+{
+  return &__x;
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+__unsafe_unretained _Tp*
+addressof(__unsafe_unretained _Tp& __x) _NOEXCEPT
+{
+  return &__x;
+}
+#endif
+
+#if !defined(_LIBCPP_CXX03_LANG)
+template <class _Tp> _Tp* addressof(const _Tp&&) noexcept = delete;
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_ADDRESSOF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/allocation_guard.h b/contrib/libs/cxxsupp/libcxx/include/__memory/allocation_guard.h
new file mode 100644
index 00000000000..6412677aaf1
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/allocation_guard.h
@@ -0,0 +1,83 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_ALLOCATION_GUARD_H
+#define _LIBCPP___MEMORY_ALLOCATION_GUARD_H
+
+#include <__config>
+#include <__memory/allocator_traits.h>
+#include <cstddef>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Helper class to allocate memory using an Allocator in an exception safe
+// manner.
+//
+// The intended usage of this class is as follows:
+//
+// 0
+// 1     __allocation_guard<SomeAllocator> guard(alloc, 10);
+// 2     do_some_initialization_that_may_throw(guard.__get());
+// 3     save_allocated_pointer_in_a_noexcept_operation(guard.__release_ptr());
+// 4
+//
+// If line (2) throws an exception during initialization of the memory, the
+// guard's destructor will be called, and the memory will be released using
+// Allocator deallocation. Otherwise, we release the memory from the guard on
+// line (3) in an operation that can't throw -- after that, the guard is not
+// responsible for the memory anymore.
+//
+// This is similar to a unique_ptr, except it's easier to use with a
+// custom allocator.
+template<class _Alloc>
+struct __allocation_guard {
+    using _Pointer = typename allocator_traits<_Alloc>::pointer;
+    using _Size = typename allocator_traits<_Alloc>::size_type;
+
+    template<class _AllocT> // we perform the allocator conversion inside the constructor
+    _LIBCPP_HIDE_FROM_ABI
+    explicit __allocation_guard(_AllocT __alloc, _Size __n)
+        : __alloc_(_VSTD::move(__alloc))
+        , __n_(__n)
+        , __ptr_(allocator_traits<_Alloc>::allocate(__alloc_, __n_)) // initialization order is important
+    { }
+
+    _LIBCPP_HIDE_FROM_ABI
+    ~__allocation_guard() _NOEXCEPT {
+        if (__ptr_ != nullptr) {
+            allocator_traits<_Alloc>::deallocate(__alloc_, __ptr_, __n_);
+        }
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    _Pointer __release_ptr() _NOEXCEPT { // not called __release() because it's a keyword in objective-c++
+        _Pointer __tmp = __ptr_;
+        __ptr_ = nullptr;
+        return __tmp;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    _Pointer __get() const _NOEXCEPT {
+        return __ptr_;
+    }
+
+private:
+    _Alloc __alloc_;
+    _Size __n_;
+    _Pointer __ptr_;
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_ALLOCATION_GUARD_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/allocator.h b/contrib/libs/cxxsupp/libcxx/include/__memory/allocator.h
new file mode 100644
index 00000000000..7913a19c106
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/allocator.h
@@ -0,0 +1,251 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_ALLOCATOR_H
+#define _LIBCPP___MEMORY_ALLOCATOR_H
+
+#include <__config>
+#include <__memory/allocator_traits.h>
+#include <__utility/forward.h>
+#include <cstddef>
+#include <new>
+#include <stdexcept>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp> class allocator;
+
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS)
+template <>
+class _LIBCPP_TEMPLATE_VIS allocator<void>
+{
+public:
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef void*             pointer;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef const void*       const_pointer;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef void              value_type;
+
+    template <class _Up> struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {typedef allocator<_Up> other;};
+};
+
+template <>
+class _LIBCPP_TEMPLATE_VIS allocator<const void>
+{
+public:
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef const void*       pointer;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef const void*       const_pointer;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef const void        value_type;
+
+    template <class _Up> struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {typedef allocator<_Up> other;};
+};
+#endif
+
+// This class provides a non-trivial default constructor to the class that derives from it
+// if the condition is satisfied.
+//
+// The second template parameter exists to allow giving a unique type to __non_trivial_if,
+// which makes it possible to avoid breaking the ABI when making this a base class of an
+// existing class. Without that, imagine we have classes D1 and D2, both of which used to
+// have no base classes, but which now derive from __non_trivial_if. The layout of a class
+// that inherits from both D1 and D2 will change because the two __non_trivial_if base
+// classes are not allowed to share the same address.
+//
+// By making those __non_trivial_if base classes unique, we work around this problem and
+// it is safe to start deriving from __non_trivial_if in existing classes.
+template <bool _Cond, class _Unique>
+struct __non_trivial_if { };
+
+template <class _Unique>
+struct __non_trivial_if<true, _Unique> {
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR __non_trivial_if() _NOEXCEPT { }
+};
+
+// allocator
+//
+// Note: For ABI compatibility between C++20 and previous standards, we make
+//       allocator<void> trivial in C++20.
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS allocator
+    : private __non_trivial_if<!is_void<_Tp>::value, allocator<_Tp> >
+{
+    static_assert(!is_volatile<_Tp>::value, "std::allocator does not support volatile types");
+public:
+    typedef size_t      size_type;
+    typedef ptrdiff_t   difference_type;
+    typedef _Tp         value_type;
+    typedef true_type   propagate_on_container_move_assignment;
+    typedef true_type   is_always_equal;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    allocator() _NOEXCEPT _LIBCPP_DEFAULT
+
+    template <class _Up>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    allocator(const allocator<_Up>&) _NOEXCEPT { }
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    _Tp* allocate(size_t __n) {
+        if (__n > allocator_traits<allocator>::max_size(*this))
+            __throw_length_error("allocator<T>::allocate(size_t n)"
+                                 " 'n' exceeds maximum supported size");
+        if (__libcpp_is_constant_evaluated()) {
+            return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
+        } else {
+            return static_cast<_Tp*>(_VSTD::__libcpp_allocate(__n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)));
+        }
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    void deallocate(_Tp* __p, size_t __n) _NOEXCEPT {
+        if (__libcpp_is_constant_evaluated()) {
+            ::operator delete((void*)__p);
+        } else {
+            _VSTD::__libcpp_deallocate((void*)__p, __n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp));
+        }
+    }
+
+    // C++20 Removed members
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp*       pointer;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp* const_pointer;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp&       reference;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp& const_reference;
+
+    template <class _Up>
+    struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {
+        typedef allocator<_Up> other;
+    };
+
+    _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
+    pointer address(reference __x) const _NOEXCEPT {
+        return _VSTD::addressof(__x);
+    }
+    _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
+    const_pointer address(const_reference __x) const _NOEXCEPT {
+        return _VSTD::addressof(__x);
+    }
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_IN_CXX17
+    _Tp* allocate(size_t __n, const void*) {
+        return allocate(__n);
+    }
+
+    _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT {
+        return size_type(~0) / sizeof(_Tp);
+    }
+
+    template <class _Up, class... _Args>
+    _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
+    void construct(_Up* __p, _Args&&... __args) {
+        ::new ((void*)__p) _Up(_VSTD::forward<_Args>(__args)...);
+    }
+
+    _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
+    void destroy(pointer __p) {
+        __p->~_Tp();
+    }
+#endif
+};
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS allocator<const _Tp>
+    : private __non_trivial_if<!is_void<_Tp>::value, allocator<const _Tp> >
+{
+    static_assert(!is_volatile<_Tp>::value, "std::allocator does not support volatile types");
+public:
+    typedef size_t      size_type;
+    typedef ptrdiff_t   difference_type;
+    typedef const _Tp   value_type;
+    typedef true_type   propagate_on_container_move_assignment;
+    typedef true_type   is_always_equal;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    allocator() _NOEXCEPT _LIBCPP_DEFAULT
+
+    template <class _Up>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    allocator(const allocator<_Up>&) _NOEXCEPT { }
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    const _Tp* allocate(size_t __n) {
+        if (__n > allocator_traits<allocator>::max_size(*this))
+            __throw_length_error("allocator<const T>::allocate(size_t n)"
+                                 " 'n' exceeds maximum supported size");
+        if (__libcpp_is_constant_evaluated()) {
+            return static_cast<const _Tp*>(::operator new(__n * sizeof(_Tp)));
+        } else {
+            return static_cast<const _Tp*>(_VSTD::__libcpp_allocate(__n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)));
+        }
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    void deallocate(const _Tp* __p, size_t __n) {
+        if (__libcpp_is_constant_evaluated()) {
+            ::operator delete(const_cast<_Tp*>(__p));
+        } else {
+            _VSTD::__libcpp_deallocate((void*) const_cast<_Tp *>(__p), __n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp));
+        }
+    }
+
+    // C++20 Removed members
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp* pointer;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp* const_pointer;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp& reference;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp& const_reference;
+
+    template <class _Up>
+    struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {
+        typedef allocator<_Up> other;
+    };
+
+    _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
+    const_pointer address(const_reference __x) const _NOEXCEPT {
+        return _VSTD::addressof(__x);
+    }
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_IN_CXX17
+    const _Tp* allocate(size_t __n, const void*) {
+        return allocate(__n);
+    }
+
+    _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT {
+        return size_type(~0) / sizeof(_Tp);
+    }
+
+    template <class _Up, class... _Args>
+    _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
+    void construct(_Up* __p, _Args&&... __args) {
+        ::new ((void*)__p) _Up(_VSTD::forward<_Args>(__args)...);
+    }
+
+    _LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_INLINE_VISIBILITY
+    void destroy(pointer __p) {
+        __p->~_Tp();
+    }
+#endif
+};
+
+template <class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool operator==(const allocator<_Tp>&, const allocator<_Up>&) _NOEXCEPT {return true;}
+
+template <class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+bool operator!=(const allocator<_Tp>&, const allocator<_Up>&) _NOEXCEPT {return false;}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_ALLOCATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/allocator_arg_t.h b/contrib/libs/cxxsupp/libcxx/include/__memory/allocator_arg_t.h
new file mode 100644
index 00000000000..f5a116dbbd7
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/allocator_arg_t.h
@@ -0,0 +1,78 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___FUNCTIONAL_ALLOCATOR_ARG_T_H
+#define _LIBCPP___FUNCTIONAL_ALLOCATOR_ARG_T_H
+
+#include <__config>
+#include <__memory/uses_allocator.h>
+#include <__utility/forward.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+struct _LIBCPP_TEMPLATE_VIS allocator_arg_t { explicit allocator_arg_t() = default; };
+
+#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
+extern _LIBCPP_EXPORTED_FROM_ABI const allocator_arg_t allocator_arg;
+#else
+/* inline */ constexpr allocator_arg_t allocator_arg = allocator_arg_t();
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+
+// allocator construction
+
+template <class _Tp, class _Alloc, class ..._Args>
+struct __uses_alloc_ctor_imp
+{
+    typedef _LIBCPP_NODEBUG typename __uncvref<_Alloc>::type _RawAlloc;
+    static const bool __ua = uses_allocator<_Tp, _RawAlloc>::value;
+    static const bool __ic =
+        is_constructible<_Tp, allocator_arg_t, _Alloc, _Args...>::value;
+    static const int value = __ua ? 2 - __ic : 0;
+};
+
+template <class _Tp, class _Alloc, class ..._Args>
+struct __uses_alloc_ctor
+    : integral_constant<int, __uses_alloc_ctor_imp<_Tp, _Alloc, _Args...>::value>
+    {};
+
+template <class _Tp, class _Allocator, class... _Args>
+inline _LIBCPP_INLINE_VISIBILITY
+void __user_alloc_construct_impl (integral_constant<int, 0>, _Tp *__storage, const _Allocator &, _Args &&... __args )
+{
+    new (__storage) _Tp (_VSTD::forward<_Args>(__args)...);
+}
+
+// FIXME: This should have a version which takes a non-const alloc.
+template <class _Tp, class _Allocator, class... _Args>
+inline _LIBCPP_INLINE_VISIBILITY
+void __user_alloc_construct_impl (integral_constant<int, 1>, _Tp *__storage, const _Allocator &__a, _Args &&... __args )
+{
+    new (__storage) _Tp (allocator_arg, __a, _VSTD::forward<_Args>(__args)...);
+}
+
+// FIXME: This should have a version which takes a non-const alloc.
+template <class _Tp, class _Allocator, class... _Args>
+inline _LIBCPP_INLINE_VISIBILITY
+void __user_alloc_construct_impl (integral_constant<int, 2>, _Tp *__storage, const _Allocator &__a, _Args &&... __args )
+{
+    new (__storage) _Tp (_VSTD::forward<_Args>(__args)..., __a);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___FUNCTIONAL_ALLOCATOR_ARG_T_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/allocator_traits.h b/contrib/libs/cxxsupp/libcxx/include/__memory/allocator_traits.h
new file mode 100644
index 00000000000..f4c8fa02d65
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/allocator_traits.h
@@ -0,0 +1,405 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_ALLOCATOR_TRAITS_H
+#define _LIBCPP___MEMORY_ALLOCATOR_TRAITS_H
+
+#include <__config>
+#include <__memory/construct_at.h>
+#include <__memory/pointer_traits.h>
+#include <__utility/forward.h>
+#include <limits>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#define _LIBCPP_ALLOCATOR_TRAITS_HAS_XXX(NAME, PROPERTY)                \
+    template <class _Tp, class = void> struct NAME : false_type { };    \
+    template <class _Tp>               struct NAME<_Tp, typename __void_t<typename _Tp:: PROPERTY >::type> : true_type { }
+
+// __pointer
+_LIBCPP_ALLOCATOR_TRAITS_HAS_XXX(__has_pointer, pointer);
+template <class _Tp, class _Alloc,
+          class _RawAlloc = typename remove_reference<_Alloc>::type,
+          bool = __has_pointer<_RawAlloc>::value>
+struct __pointer {
+    using type _LIBCPP_NODEBUG = typename _RawAlloc::pointer;
+};
+template <class _Tp, class _Alloc, class _RawAlloc>
+struct __pointer<_Tp, _Alloc, _RawAlloc, false> {
+    using type _LIBCPP_NODEBUG = _Tp*;
+};
+
+// __const_pointer
+_LIBCPP_ALLOCATOR_TRAITS_HAS_XXX(__has_const_pointer, const_pointer);
+template <class _Tp, class _Ptr, class _Alloc,
+          bool = __has_const_pointer<_Alloc>::value>
+struct __const_pointer {
+    using type _LIBCPP_NODEBUG = typename _Alloc::const_pointer;
+};
+template <class _Tp, class _Ptr, class _Alloc>
+struct __const_pointer<_Tp, _Ptr, _Alloc, false> {
+#ifdef _LIBCPP_CXX03_LANG
+    using type = typename pointer_traits<_Ptr>::template rebind<const _Tp>::other;
+#else
+    using type _LIBCPP_NODEBUG = typename pointer_traits<_Ptr>::template rebind<const _Tp>;
+#endif
+};
+
+// __void_pointer
+_LIBCPP_ALLOCATOR_TRAITS_HAS_XXX(__has_void_pointer, void_pointer);
+template <class _Ptr, class _Alloc,
+          bool = __has_void_pointer<_Alloc>::value>
+struct __void_pointer {
+    using type _LIBCPP_NODEBUG = typename _Alloc::void_pointer;
+};
+template <class _Ptr, class _Alloc>
+struct __void_pointer<_Ptr, _Alloc, false> {
+#ifdef _LIBCPP_CXX03_LANG
+    using type _LIBCPP_NODEBUG = typename pointer_traits<_Ptr>::template rebind<void>::other;
+#else
+    using type _LIBCPP_NODEBUG = typename pointer_traits<_Ptr>::template rebind<void>;
+#endif
+};
+
+// __const_void_pointer
+_LIBCPP_ALLOCATOR_TRAITS_HAS_XXX(__has_const_void_pointer, const_void_pointer);
+template <class _Ptr, class _Alloc,
+          bool = __has_const_void_pointer<_Alloc>::value>
+struct __const_void_pointer {
+    using type _LIBCPP_NODEBUG = typename _Alloc::const_void_pointer;
+};
+template <class _Ptr, class _Alloc>
+struct __const_void_pointer<_Ptr, _Alloc, false> {
+#ifdef _LIBCPP_CXX03_LANG
+    using type _LIBCPP_NODEBUG = typename pointer_traits<_Ptr>::template rebind<const void>::other;
+#else
+    using type _LIBCPP_NODEBUG = typename pointer_traits<_Ptr>::template rebind<const void>;
+#endif
+};
+
+// __size_type
+_LIBCPP_ALLOCATOR_TRAITS_HAS_XXX(__has_size_type, size_type);
+template <class _Alloc, class _DiffType, bool = __has_size_type<_Alloc>::value>
+struct __size_type : make_unsigned<_DiffType> { };
+template <class _Alloc, class _DiffType>
+struct __size_type<_Alloc, _DiffType, true> {
+    using type _LIBCPP_NODEBUG = typename _Alloc::size_type;
+};
+
+// __alloc_traits_difference_type
+_LIBCPP_ALLOCATOR_TRAITS_HAS_XXX(__has_alloc_traits_difference_type, difference_type);
+template <class _Alloc, class _Ptr, bool = __has_alloc_traits_difference_type<_Alloc>::value>
+struct __alloc_traits_difference_type {
+    using type _LIBCPP_NODEBUG = typename pointer_traits<_Ptr>::difference_type;
+};
+template <class _Alloc, class _Ptr>
+struct __alloc_traits_difference_type<_Alloc, _Ptr, true> {
+    using type _LIBCPP_NODEBUG = typename _Alloc::difference_type;
+};
+
+// __propagate_on_container_copy_assignment
+_LIBCPP_ALLOCATOR_TRAITS_HAS_XXX(__has_propagate_on_container_copy_assignment, propagate_on_container_copy_assignment);
+template <class _Alloc, bool = __has_propagate_on_container_copy_assignment<_Alloc>::value>
+struct __propagate_on_container_copy_assignment : false_type { };
+template <class _Alloc>
+struct __propagate_on_container_copy_assignment<_Alloc, true> {
+    using type _LIBCPP_NODEBUG = typename _Alloc::propagate_on_container_copy_assignment;
+};
+
+// __propagate_on_container_move_assignment
+_LIBCPP_ALLOCATOR_TRAITS_HAS_XXX(__has_propagate_on_container_move_assignment, propagate_on_container_move_assignment);
+template <class _Alloc, bool = __has_propagate_on_container_move_assignment<_Alloc>::value>
+struct __propagate_on_container_move_assignment : false_type { };
+template <class _Alloc>
+struct __propagate_on_container_move_assignment<_Alloc, true> {
+    using type _LIBCPP_NODEBUG = typename _Alloc::propagate_on_container_move_assignment;
+};
+
+// __propagate_on_container_swap
+_LIBCPP_ALLOCATOR_TRAITS_HAS_XXX(__has_propagate_on_container_swap, propagate_on_container_swap);
+template <class _Alloc, bool = __has_propagate_on_container_swap<_Alloc>::value>
+struct __propagate_on_container_swap : false_type { };
+template <class _Alloc>
+struct __propagate_on_container_swap<_Alloc, true> {
+    using type _LIBCPP_NODEBUG = typename _Alloc::propagate_on_container_swap;
+};
+
+// __is_always_equal
+_LIBCPP_ALLOCATOR_TRAITS_HAS_XXX(__has_is_always_equal, is_always_equal);
+template <class _Alloc, bool = __has_is_always_equal<_Alloc>::value>
+struct __is_always_equal : is_empty<_Alloc> { };
+template <class _Alloc>
+struct __is_always_equal<_Alloc, true> {
+    using type _LIBCPP_NODEBUG = typename _Alloc::is_always_equal;
+};
+
+// __allocator_traits_rebind
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp, class _Up, class = void>
+struct __has_rebind_other : false_type { };
+template <class _Tp, class _Up>
+struct __has_rebind_other<_Tp, _Up, typename __void_t<
+    typename _Tp::template rebind<_Up>::other
+>::type> : true_type { };
+
+template <class _Tp, class _Up, bool = __has_rebind_other<_Tp, _Up>::value>
+struct __allocator_traits_rebind {
+    using type _LIBCPP_NODEBUG = typename _Tp::template rebind<_Up>::other;
+};
+template <template <class, class...> class _Alloc, class _Tp, class ..._Args, class _Up>
+struct __allocator_traits_rebind<_Alloc<_Tp, _Args...>, _Up, true> {
+    using type _LIBCPP_NODEBUG = typename _Alloc<_Tp, _Args...>::template rebind<_Up>::other;
+};
+template <template <class, class...> class _Alloc, class _Tp, class ..._Args, class _Up>
+struct __allocator_traits_rebind<_Alloc<_Tp, _Args...>, _Up, false> {
+    using type _LIBCPP_NODEBUG = _Alloc<_Up, _Args...>;
+};
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+template<class _Alloc, class _Tp>
+using __allocator_traits_rebind_t = typename __allocator_traits_rebind<_Alloc, _Tp>::type;
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+
+// __has_allocate_hint
+template <class _Alloc, class _SizeType, class _ConstVoidPtr, class = void>
+struct __has_allocate_hint : false_type { };
+
+template <class _Alloc, class _SizeType, class _ConstVoidPtr>
+struct __has_allocate_hint<_Alloc, _SizeType, _ConstVoidPtr, decltype(
+    (void)declval<_Alloc>().allocate(declval<_SizeType>(), declval<_ConstVoidPtr>())
+)> : true_type { };
+
+// __has_construct
+template <class, class _Alloc, class ..._Args>
+struct __has_construct_impl : false_type { };
+
+template <class _Alloc, class ..._Args>
+struct __has_construct_impl<decltype(
+    (void)declval<_Alloc>().construct(declval<_Args>()...)
+), _Alloc, _Args...> : true_type { };
+
+template <class _Alloc, class ..._Args>
+struct __has_construct : __has_construct_impl<void, _Alloc, _Args...> { };
+
+// __has_destroy
+template <class _Alloc, class _Pointer, class = void>
+struct __has_destroy : false_type { };
+
+template <class _Alloc, class _Pointer>
+struct __has_destroy<_Alloc, _Pointer, decltype(
+    (void)declval<_Alloc>().destroy(declval<_Pointer>())
+)> : true_type { };
+
+// __has_max_size
+template <class _Alloc, class = void>
+struct __has_max_size : false_type { };
+
+template <class _Alloc>
+struct __has_max_size<_Alloc, decltype(
+    (void)declval<_Alloc&>().max_size()
+)> : true_type { };
+
+// __has_select_on_container_copy_construction
+template <class _Alloc, class = void>
+struct __has_select_on_container_copy_construction : false_type { };
+
+template <class _Alloc>
+struct __has_select_on_container_copy_construction<_Alloc, decltype(
+    (void)declval<_Alloc>().select_on_container_copy_construction()
+)> : true_type { };
+
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+template <class _Alloc>
+struct _LIBCPP_TEMPLATE_VIS allocator_traits
+{
+    using allocator_type = _Alloc;
+    using value_type = typename allocator_type::value_type;
+    using pointer = typename __pointer<value_type, allocator_type>::type;
+    using const_pointer = typename __const_pointer<value_type, pointer, allocator_type>::type;
+    using void_pointer = typename __void_pointer<pointer, allocator_type>::type;
+    using const_void_pointer = typename __const_void_pointer<pointer, allocator_type>::type;
+    using difference_type = typename __alloc_traits_difference_type<allocator_type, pointer>::type;
+    using size_type = typename __size_type<allocator_type, difference_type>::type;
+    using propagate_on_container_copy_assignment = typename __propagate_on_container_copy_assignment<allocator_type>::type;
+    using propagate_on_container_move_assignment = typename __propagate_on_container_move_assignment<allocator_type>::type;
+    using propagate_on_container_swap = typename __propagate_on_container_swap<allocator_type>::type;
+    using is_always_equal = typename __is_always_equal<allocator_type>::type;
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _Tp>
+    using rebind_alloc = __allocator_traits_rebind_t<allocator_type, _Tp>;
+    template <class _Tp>
+    using rebind_traits = allocator_traits<rebind_alloc<_Tp> >;
+#else  // _LIBCPP_CXX03_LANG
+    template <class _Tp>
+    struct rebind_alloc {
+        using other = __allocator_traits_rebind_t<allocator_type, _Tp>;
+    };
+    template <class _Tp>
+    struct rebind_traits {
+        using other = allocator_traits<typename rebind_alloc<_Tp>::other>;
+    };
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static pointer allocate(allocator_type& __a, size_type __n) {
+        return __a.allocate(__n);
+    }
+
+    template <class _Ap = _Alloc, class =
+        __enable_if_t<__has_allocate_hint<_Ap, size_type, const_void_pointer>::value> >
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static pointer allocate(allocator_type& __a, size_type __n, const_void_pointer __hint) {
+        _LIBCPP_SUPPRESS_DEPRECATED_PUSH
+        return __a.allocate(__n, __hint);
+        _LIBCPP_SUPPRESS_DEPRECATED_POP
+    }
+    template <class _Ap = _Alloc, class = void, class =
+        __enable_if_t<!__has_allocate_hint<_Ap, size_type, const_void_pointer>::value> >
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static pointer allocate(allocator_type& __a, size_type __n, const_void_pointer) {
+        return __a.allocate(__n);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static void deallocate(allocator_type& __a, pointer __p, size_type __n) _NOEXCEPT {
+        __a.deallocate(__p, __n);
+    }
+
+    template <class _Tp, class... _Args, class =
+        __enable_if_t<__has_construct<allocator_type, _Tp*, _Args...>::value> >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static void construct(allocator_type& __a, _Tp* __p, _Args&&... __args) {
+        _LIBCPP_SUPPRESS_DEPRECATED_PUSH
+        __a.construct(__p, _VSTD::forward<_Args>(__args)...);
+        _LIBCPP_SUPPRESS_DEPRECATED_POP
+    }
+    template <class _Tp, class... _Args, class = void, class =
+        __enable_if_t<!__has_construct<allocator_type, _Tp*, _Args...>::value> >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static void construct(allocator_type&, _Tp* __p, _Args&&... __args) {
+#if _LIBCPP_STD_VER > 17
+        _VSTD::construct_at(__p, _VSTD::forward<_Args>(__args)...);
+#else
+        ::new ((void*)__p) _Tp(_VSTD::forward<_Args>(__args)...);
+#endif
+    }
+
+    template <class _Tp, class =
+        __enable_if_t<__has_destroy<allocator_type, _Tp*>::value> >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static void destroy(allocator_type& __a, _Tp* __p) {
+        _LIBCPP_SUPPRESS_DEPRECATED_PUSH
+        __a.destroy(__p);
+        _LIBCPP_SUPPRESS_DEPRECATED_POP
+    }
+    template <class _Tp, class = void, class =
+        __enable_if_t<!__has_destroy<allocator_type, _Tp*>::value> >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static void destroy(allocator_type&, _Tp* __p) {
+#if _LIBCPP_STD_VER > 17
+        _VSTD::destroy_at(__p);
+#else
+        __p->~_Tp();
+#endif
+    }
+
+    template <class _Ap = _Alloc, class =
+        __enable_if_t<__has_max_size<const _Ap>::value> >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static size_type max_size(const allocator_type& __a) _NOEXCEPT {
+        _LIBCPP_SUPPRESS_DEPRECATED_PUSH
+        return __a.max_size();
+        _LIBCPP_SUPPRESS_DEPRECATED_POP
+    }
+    template <class _Ap = _Alloc, class = void, class =
+        __enable_if_t<!__has_max_size<const _Ap>::value> >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static size_type max_size(const allocator_type&) _NOEXCEPT {
+        return numeric_limits<size_type>::max() / sizeof(value_type);
+    }
+
+    template <class _Ap = _Alloc, class =
+        __enable_if_t<__has_select_on_container_copy_construction<const _Ap>::value> >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static allocator_type select_on_container_copy_construction(const allocator_type& __a) {
+        return __a.select_on_container_copy_construction();
+    }
+    template <class _Ap = _Alloc, class = void, class =
+        __enable_if_t<!__has_select_on_container_copy_construction<const _Ap>::value> >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static allocator_type select_on_container_copy_construction(const allocator_type& __a) {
+        return __a;
+    }
+};
+
+template <class _Traits, class _Tp>
+struct __rebind_alloc_helper {
+#ifndef _LIBCPP_CXX03_LANG
+    using type _LIBCPP_NODEBUG = typename _Traits::template rebind_alloc<_Tp>;
+#else
+    using type = typename _Traits::template rebind_alloc<_Tp>::other;
+#endif
+};
+
+// __is_default_allocator
+template <class _Tp>
+struct __is_default_allocator : false_type { };
+
+template <class> class allocator;
+
+template <class _Tp>
+struct __is_default_allocator<allocator<_Tp> > : true_type { };
+
+// __is_cpp17_move_insertable
+template <class _Alloc, class = void>
+struct __is_cpp17_move_insertable
+    : is_move_constructible<typename _Alloc::value_type>
+{ };
+
+template <class _Alloc>
+struct __is_cpp17_move_insertable<_Alloc, __enable_if_t<
+    !__is_default_allocator<_Alloc>::value &&
+    __has_construct<_Alloc, typename _Alloc::value_type*, typename _Alloc::value_type&&>::value
+> > : true_type { };
+
+// __is_cpp17_copy_insertable
+template <class _Alloc, class = void>
+struct __is_cpp17_copy_insertable
+    : integral_constant<bool,
+        is_copy_constructible<typename _Alloc::value_type>::value &&
+        __is_cpp17_move_insertable<_Alloc>::value
+    >
+{ };
+
+template <class _Alloc>
+struct __is_cpp17_copy_insertable<_Alloc, __enable_if_t<
+    !__is_default_allocator<_Alloc>::value &&
+    __has_construct<_Alloc, typename _Alloc::value_type*, const typename _Alloc::value_type&>::value
+> >
+    : __is_cpp17_move_insertable<_Alloc>
+{ };
+
+#undef _LIBCPP_ALLOCATOR_TRAITS_HAS_XXX
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___MEMORY_ALLOCATOR_TRAITS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/auto_ptr.h b/contrib/libs/cxxsupp/libcxx/include/__memory/auto_ptr.h
new file mode 100644
index 00000000000..492cbabab8a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/auto_ptr.h
@@ -0,0 +1,81 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_AUTO_PTR_H
+#define _LIBCPP___MEMORY_AUTO_PTR_H
+
+#include <__config>
+#include <__nullptr>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+struct _LIBCPP_DEPRECATED_IN_CXX11 auto_ptr_ref
+{
+    _Tp* __ptr_;
+};
+
+template<class _Tp>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 auto_ptr
+{
+private:
+    _Tp* __ptr_;
+public:
+    typedef _Tp element_type;
+
+    _LIBCPP_INLINE_VISIBILITY explicit auto_ptr(_Tp* __p = 0) _NOEXCEPT : __ptr_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY auto_ptr(auto_ptr& __p) _NOEXCEPT : __ptr_(__p.release()) {}
+    template<class _Up> _LIBCPP_INLINE_VISIBILITY auto_ptr(auto_ptr<_Up>& __p) _NOEXCEPT
+        : __ptr_(__p.release()) {}
+    _LIBCPP_INLINE_VISIBILITY auto_ptr& operator=(auto_ptr& __p) _NOEXCEPT
+        {reset(__p.release()); return *this;}
+    template<class _Up> _LIBCPP_INLINE_VISIBILITY auto_ptr& operator=(auto_ptr<_Up>& __p) _NOEXCEPT
+        {reset(__p.release()); return *this;}
+    _LIBCPP_INLINE_VISIBILITY auto_ptr& operator=(auto_ptr_ref<_Tp> __p) _NOEXCEPT
+        {reset(__p.__ptr_); return *this;}
+    _LIBCPP_INLINE_VISIBILITY ~auto_ptr() _NOEXCEPT {delete __ptr_;}
+
+    _LIBCPP_INLINE_VISIBILITY _Tp& operator*() const _NOEXCEPT
+        {return *__ptr_;}
+    _LIBCPP_INLINE_VISIBILITY _Tp* operator->() const _NOEXCEPT {return __ptr_;}
+    _LIBCPP_INLINE_VISIBILITY _Tp* get() const _NOEXCEPT {return __ptr_;}
+    _LIBCPP_INLINE_VISIBILITY _Tp* release() _NOEXCEPT
+    {
+        _Tp* __t = __ptr_;
+        __ptr_ = nullptr;
+        return __t;
+    }
+    _LIBCPP_INLINE_VISIBILITY void reset(_Tp* __p = 0) _NOEXCEPT
+    {
+        if (__ptr_ != __p)
+            delete __ptr_;
+        __ptr_ = __p;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY auto_ptr(auto_ptr_ref<_Tp> __p) _NOEXCEPT : __ptr_(__p.__ptr_) {}
+    template<class _Up> _LIBCPP_INLINE_VISIBILITY operator auto_ptr_ref<_Up>() _NOEXCEPT
+        {auto_ptr_ref<_Up> __t; __t.__ptr_ = release(); return __t;}
+    template<class _Up> _LIBCPP_INLINE_VISIBILITY operator auto_ptr<_Up>() _NOEXCEPT
+        {return auto_ptr<_Up>(release());}
+};
+
+template <>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX11 auto_ptr<void>
+{
+public:
+    typedef void element_type;
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_AUTO_PTR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/compressed_pair.h b/contrib/libs/cxxsupp/libcxx/include/__memory/compressed_pair.h
new file mode 100644
index 00000000000..fd1fcbe5bf3
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/compressed_pair.h
@@ -0,0 +1,196 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_COMPRESSED_PAIR_H
+#define _LIBCPP___MEMORY_COMPRESSED_PAIR_H
+
+#include <__config>
+#include <__utility/forward.h>
+#include <tuple> // needed in c++03 for some constructors
+#include <type_traits>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Tag used to default initialize one or both of the pair's elements.
+struct __default_init_tag {};
+struct __value_init_tag {};
+
+template <class _Tp, int _Idx,
+          bool _CanBeEmptyBase =
+              is_empty<_Tp>::value && !__libcpp_is_final<_Tp>::value>
+struct __compressed_pair_elem {
+  typedef _Tp _ParamT;
+  typedef _Tp& reference;
+  typedef const _Tp& const_reference;
+
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+  __compressed_pair_elem(__default_init_tag) {}
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+  __compressed_pair_elem(__value_init_tag) : __value_() {}
+
+  template <class _Up, class = typename enable_if<
+      !is_same<__compressed_pair_elem, typename decay<_Up>::type>::value
+  >::type>
+  _LIBCPP_INLINE_VISIBILITY
+  _LIBCPP_CONSTEXPR explicit
+  __compressed_pair_elem(_Up&& __u)
+      : __value_(_VSTD::forward<_Up>(__u))
+    {
+    }
+
+
+#ifndef _LIBCPP_CXX03_LANG
+  template <class... _Args, size_t... _Indexes>
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+  __compressed_pair_elem(piecewise_construct_t, tuple<_Args...> __args,
+                         __tuple_indices<_Indexes...>)
+      : __value_(_VSTD::forward<_Args>(_VSTD::get<_Indexes>(__args))...) {}
+#endif
+
+
+  _LIBCPP_INLINE_VISIBILITY reference __get() _NOEXCEPT { return __value_; }
+  _LIBCPP_INLINE_VISIBILITY
+  const_reference __get() const _NOEXCEPT { return __value_; }
+
+private:
+  _Tp __value_;
+};
+
+template <class _Tp, int _Idx>
+struct __compressed_pair_elem<_Tp, _Idx, true> : private _Tp {
+  typedef _Tp _ParamT;
+  typedef _Tp& reference;
+  typedef const _Tp& const_reference;
+  typedef _Tp __value_type;
+
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR __compressed_pair_elem() = default;
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+  __compressed_pair_elem(__default_init_tag) {}
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+  __compressed_pair_elem(__value_init_tag) : __value_type() {}
+
+  template <class _Up, class = typename enable_if<
+        !is_same<__compressed_pair_elem, typename decay<_Up>::type>::value
+  >::type>
+  _LIBCPP_INLINE_VISIBILITY
+  _LIBCPP_CONSTEXPR explicit
+  __compressed_pair_elem(_Up&& __u)
+      : __value_type(_VSTD::forward<_Up>(__u))
+  {}
+
+#ifndef _LIBCPP_CXX03_LANG
+  template <class... _Args, size_t... _Indexes>
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+  __compressed_pair_elem(piecewise_construct_t, tuple<_Args...> __args,
+                         __tuple_indices<_Indexes...>)
+      : __value_type(_VSTD::forward<_Args>(_VSTD::get<_Indexes>(__args))...) {}
+#endif
+
+  _LIBCPP_INLINE_VISIBILITY reference __get() _NOEXCEPT { return *this; }
+  _LIBCPP_INLINE_VISIBILITY
+  const_reference __get() const _NOEXCEPT { return *this; }
+};
+
+template <class _T1, class _T2>
+class __compressed_pair : private __compressed_pair_elem<_T1, 0>,
+                          private __compressed_pair_elem<_T2, 1> {
+public:
+  // NOTE: This static assert should never fire because __compressed_pair
+  // is *almost never* used in a scenario where it's possible for T1 == T2.
+  // (The exception is std::function where it is possible that the function
+  //  object and the allocator have the same type).
+  static_assert((!is_same<_T1, _T2>::value),
+    "__compressed_pair cannot be instantiated when T1 and T2 are the same type; "
+    "The current implementation is NOT ABI-compatible with the previous "
+    "implementation for this configuration");
+
+    typedef _LIBCPP_NODEBUG __compressed_pair_elem<_T1, 0> _Base1;
+    typedef _LIBCPP_NODEBUG __compressed_pair_elem<_T2, 1> _Base2;
+
+    template <bool _Dummy = true,
+      class = typename enable_if<
+          __dependent_type<is_default_constructible<_T1>, _Dummy>::value &&
+          __dependent_type<is_default_constructible<_T2>, _Dummy>::value
+      >::type
+  >
+  _LIBCPP_INLINE_VISIBILITY
+  _LIBCPP_CONSTEXPR __compressed_pair() : _Base1(__value_init_tag()), _Base2(__value_init_tag()) {}
+
+  template <class _U1, class _U2>
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+  __compressed_pair(_U1&& __t1, _U2&& __t2)
+      : _Base1(_VSTD::forward<_U1>(__t1)), _Base2(_VSTD::forward<_U2>(__t2)) {}
+
+#ifndef _LIBCPP_CXX03_LANG
+  template <class... _Args1, class... _Args2>
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+  __compressed_pair(piecewise_construct_t __pc, tuple<_Args1...> __first_args,
+                    tuple<_Args2...> __second_args)
+      : _Base1(__pc, _VSTD::move(__first_args),
+               typename __make_tuple_indices<sizeof...(_Args1)>::type()),
+        _Base2(__pc, _VSTD::move(__second_args),
+               typename __make_tuple_indices<sizeof...(_Args2)>::type()) {}
+#endif
+
+  _LIBCPP_INLINE_VISIBILITY
+  typename _Base1::reference first() _NOEXCEPT {
+    return static_cast<_Base1&>(*this).__get();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  typename _Base1::const_reference first() const _NOEXCEPT {
+    return static_cast<_Base1 const&>(*this).__get();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  typename _Base2::reference second() _NOEXCEPT {
+    return static_cast<_Base2&>(*this).__get();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  typename _Base2::const_reference second() const _NOEXCEPT {
+    return static_cast<_Base2 const&>(*this).__get();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+  static _Base1* __get_first_base(__compressed_pair* __pair) _NOEXCEPT {
+    return static_cast<_Base1*>(__pair);
+  }
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+  static _Base2* __get_second_base(__compressed_pair* __pair) _NOEXCEPT {
+    return static_cast<_Base2*>(__pair);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void swap(__compressed_pair& __x)
+    _NOEXCEPT_(__is_nothrow_swappable<_T1>::value &&
+               __is_nothrow_swappable<_T2>::value)
+  {
+    using _VSTD::swap;
+    swap(first(), __x.first());
+    swap(second(), __x.second());
+  }
+};
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+void swap(__compressed_pair<_T1, _T2>& __x, __compressed_pair<_T1, _T2>& __y)
+    _NOEXCEPT_(__is_nothrow_swappable<_T1>::value &&
+               __is_nothrow_swappable<_T2>::value) {
+  __x.swap(__y);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_COMPRESSED_PAIR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/construct_at.h b/contrib/libs/cxxsupp/libcxx/include/__memory/construct_at.h
new file mode 100644
index 00000000000..789677d7a61
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/construct_at.h
@@ -0,0 +1,85 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_CONSTRUCT_AT_H
+#define _LIBCPP___MEMORY_CONSTRUCT_AT_H
+
+#include <__config>
+#include <__debug>
+#include <__iterator/access.h>
+#include <__memory/addressof.h>
+#include <__utility/forward.h>
+#include <type_traits>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// construct_at
+
+#if _LIBCPP_STD_VER > 17
+
+template<class _Tp, class ..._Args, class = decltype(
+    ::new (declval<void*>()) _Tp(declval<_Args>()...)
+)>
+_LIBCPP_INLINE_VISIBILITY
+constexpr _Tp* construct_at(_Tp* __location, _Args&& ...__args) {
+    _LIBCPP_ASSERT(__location, "null pointer given to construct_at");
+    return ::new ((void*)__location) _Tp(_VSTD::forward<_Args>(__args)...);
+}
+
+#endif
+
+// destroy_at
+
+#if _LIBCPP_STD_VER > 14
+
+template <class _ForwardIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
+void destroy(_ForwardIterator, _ForwardIterator);
+
+template <class _Tp, enable_if_t<!is_array_v<_Tp>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
+void destroy_at(_Tp* __loc) {
+    _LIBCPP_ASSERT(__loc, "null pointer given to destroy_at");
+    __loc->~_Tp();
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Tp, enable_if_t<is_array_v<_Tp>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
+void destroy_at(_Tp* __loc) {
+    _LIBCPP_ASSERT(__loc, "null pointer given to destroy_at");
+    _VSTD::destroy(_VSTD::begin(*__loc), _VSTD::end(*__loc));
+}
+#endif
+
+template <class _ForwardIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
+void destroy(_ForwardIterator __first, _ForwardIterator __last) {
+    for (; __first != __last; ++__first)
+        _VSTD::destroy_at(_VSTD::addressof(*__first));
+}
+
+template <class _ForwardIterator, class _Size>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
+_ForwardIterator destroy_n(_ForwardIterator __first, _Size __n) {
+    for (; __n > 0; (void)++__first, --__n)
+        _VSTD::destroy_at(_VSTD::addressof(*__first));
+    return __first;
+}
+
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_CONSTRUCT_AT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/pointer_safety.h b/contrib/libs/cxxsupp/libcxx/include/__memory/pointer_safety.h
new file mode 100644
index 00000000000..e72080393dc
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/pointer_safety.h
@@ -0,0 +1,52 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_POINTER_SAFETY_H
+#define _LIBCPP___MEMORY_POINTER_SAFETY_H
+
+#include <__config>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_CXX03_LANG)
+
+enum class pointer_safety : unsigned char {
+  relaxed,
+  preferred,
+  strict
+};
+
+inline _LIBCPP_INLINE_VISIBILITY
+pointer_safety get_pointer_safety() _NOEXCEPT {
+  return pointer_safety::relaxed;
+}
+
+_LIBCPP_FUNC_VIS void declare_reachable(void* __p);
+_LIBCPP_FUNC_VIS void declare_no_pointers(char* __p, size_t __n);
+_LIBCPP_FUNC_VIS void undeclare_no_pointers(char* __p, size_t __n);
+_LIBCPP_FUNC_VIS void* __undeclare_reachable(void* __p);
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp*
+undeclare_reachable(_Tp* __p)
+{
+    return static_cast<_Tp*>(__undeclare_reachable(__p));
+}
+
+#endif // !C++03
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_POINTER_SAFETY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/pointer_traits.h b/contrib/libs/cxxsupp/libcxx/include/__memory/pointer_traits.h
new file mode 100644
index 00000000000..53b2c32eda6
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/pointer_traits.h
@@ -0,0 +1,220 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_POINTER_TRAITS_H
+#define _LIBCPP___MEMORY_POINTER_TRAITS_H
+
+#include <__config>
+#include <__memory/addressof.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class = void>
+struct __has_element_type : false_type {};
+
+template <class _Tp>
+struct __has_element_type<_Tp,
+              typename __void_t<typename _Tp::element_type>::type> : true_type {};
+
+template <class _Ptr, bool = __has_element_type<_Ptr>::value>
+struct __pointer_traits_element_type;
+
+template <class _Ptr>
+struct __pointer_traits_element_type<_Ptr, true>
+{
+    typedef _LIBCPP_NODEBUG typename _Ptr::element_type type;
+};
+
+template <template <class, class...> class _Sp, class _Tp, class ..._Args>
+struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, true>
+{
+    typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::element_type type;
+};
+
+template <template <class, class...> class _Sp, class _Tp, class ..._Args>
+struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, false>
+{
+    typedef _LIBCPP_NODEBUG _Tp type;
+};
+
+template <class _Tp, class = void>
+struct __has_difference_type : false_type {};
+
+template <class _Tp>
+struct __has_difference_type<_Tp,
+            typename __void_t<typename _Tp::difference_type>::type> : true_type {};
+
+template <class _Ptr, bool = __has_difference_type<_Ptr>::value>
+struct __pointer_traits_difference_type
+{
+    typedef _LIBCPP_NODEBUG ptrdiff_t type;
+};
+
+template <class _Ptr>
+struct __pointer_traits_difference_type<_Ptr, true>
+{
+    typedef _LIBCPP_NODEBUG typename _Ptr::difference_type type;
+};
+
+template <class _Tp, class _Up>
+struct __has_rebind
+{
+private:
+    struct __two {char __lx; char __lxx;};
+    template <class _Xp> static __two __test(...);
+    _LIBCPP_SUPPRESS_DEPRECATED_PUSH
+    // Fix for MSVC which allows to reference private types. Wrap into declval to prevent that.
+    template <class _Xp> static char __test(decltype(_VSTD::declval<typename _Xp::template rebind<_Up>*>()) = 0);
+    _LIBCPP_SUPPRESS_DEPRECATED_POP
+public:
+    static const bool value = sizeof(__test<_Tp>(0)) == 1;
+};
+
+template <class _Tp, class _Up, bool = __has_rebind<_Tp, _Up>::value>
+struct __pointer_traits_rebind
+{
+#ifndef _LIBCPP_CXX03_LANG
+    typedef _LIBCPP_NODEBUG typename _Tp::template rebind<_Up> type;
+#else
+    typedef _LIBCPP_NODEBUG typename _Tp::template rebind<_Up>::other type;
+#endif
+};
+
+template <template <class, class...> class _Sp, class _Tp, class ..._Args, class _Up>
+struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, true>
+{
+#ifndef _LIBCPP_CXX03_LANG
+    typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::template rebind<_Up> type;
+#else
+    typedef _LIBCPP_NODEBUG typename _Sp<_Tp, _Args...>::template rebind<_Up>::other type;
+#endif
+};
+
+template <template <class, class...> class _Sp, class _Tp, class ..._Args, class _Up>
+struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, false>
+{
+    typedef _Sp<_Up, _Args...> type;
+};
+
+template <class _Ptr>
+struct _LIBCPP_TEMPLATE_VIS pointer_traits
+{
+    typedef _Ptr                                                     pointer;
+    typedef typename __pointer_traits_element_type<pointer>::type    element_type;
+    typedef typename __pointer_traits_difference_type<pointer>::type difference_type;
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _Up> using rebind = typename __pointer_traits_rebind<pointer, _Up>::type;
+#else
+    template <class _Up> struct rebind
+        {typedef typename __pointer_traits_rebind<pointer, _Up>::type other;};
+#endif // _LIBCPP_CXX03_LANG
+
+private:
+    struct __nat {};
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    static pointer pointer_to(typename conditional<is_void<element_type>::value,
+                                           __nat, element_type>::type& __r)
+        {return pointer::pointer_to(__r);}
+};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS pointer_traits<_Tp*>
+{
+    typedef _Tp*      pointer;
+    typedef _Tp       element_type;
+    typedef ptrdiff_t difference_type;
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _Up> using rebind = _Up*;
+#else
+    template <class _Up> struct rebind {typedef _Up* other;};
+#endif
+
+private:
+    struct __nat {};
+public:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static pointer pointer_to(typename conditional<is_void<element_type>::value,
+                                      __nat, element_type>::type& __r) _NOEXCEPT
+        {return _VSTD::addressof(__r);}
+};
+
+template <class _From, class _To>
+struct __rebind_pointer {
+#ifndef _LIBCPP_CXX03_LANG
+    typedef typename pointer_traits<_From>::template rebind<_To>        type;
+#else
+    typedef typename pointer_traits<_From>::template rebind<_To>::other type;
+#endif
+};
+
+// to_address
+
+template <class _Pointer, class = void>
+struct __to_address_helper;
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+_Tp* __to_address(_Tp* __p) _NOEXCEPT {
+    static_assert(!is_function<_Tp>::value, "_Tp is a function type");
+    return __p;
+}
+
+// enable_if is needed here to avoid instantiating checks for fancy pointers on raw pointers
+template <class _Pointer, class = __enable_if_t<
+    !is_pointer<_Pointer>::value && !is_array<_Pointer>::value && !is_function<_Pointer>::value
+> >
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename decay<decltype(__to_address_helper<_Pointer>::__call(declval<const _Pointer&>()))>::type
+__to_address(const _Pointer& __p) _NOEXCEPT {
+    return __to_address_helper<_Pointer>::__call(__p);
+}
+
+template <class _Pointer, class>
+struct __to_address_helper {
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    static decltype(_VSTD::__to_address(declval<const _Pointer&>().operator->()))
+    __call(const _Pointer& __p) _NOEXCEPT {
+        return _VSTD::__to_address(__p.operator->());
+    }
+};
+
+template <class _Pointer>
+struct __to_address_helper<_Pointer, decltype((void)pointer_traits<_Pointer>::to_address(declval<const _Pointer&>()))> {
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    static decltype(pointer_traits<_Pointer>::to_address(declval<const _Pointer&>()))
+    __call(const _Pointer& __p) _NOEXCEPT {
+        return pointer_traits<_Pointer>::to_address(__p);
+    }
+};
+
+#if _LIBCPP_STD_VER > 17
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY constexpr
+auto to_address(_Tp *__p) noexcept {
+    return _VSTD::__to_address(__p);
+}
+
+template <class _Pointer>
+inline _LIBCPP_INLINE_VISIBILITY constexpr
+auto to_address(const _Pointer& __p) noexcept {
+    return _VSTD::__to_address(__p);
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_POINTER_TRAITS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/raw_storage_iterator.h b/contrib/libs/cxxsupp/libcxx/include/__memory/raw_storage_iterator.h
new file mode 100644
index 00000000000..abe9677cb66
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/raw_storage_iterator.h
@@ -0,0 +1,68 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_RAW_STORAGE_ITERATOR_H
+#define _LIBCPP___MEMORY_RAW_STORAGE_ITERATOR_H
+
+#include <__config>
+#include <__memory/addressof.h>
+#include <cstddef>
+#include <iterator>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_RAW_STORAGE_ITERATOR)
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _OutputIterator, class _Tp>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 raw_storage_iterator
+#if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
+    : public iterator<output_iterator_tag, void, void, void, void>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+private:
+    _OutputIterator __x_;
+public:
+    typedef output_iterator_tag iterator_category;
+    typedef void                value_type;
+#if _LIBCPP_STD_VER > 17
+    typedef ptrdiff_t           difference_type;
+#else
+    typedef void                difference_type;
+#endif
+    typedef void                pointer;
+    typedef void                reference;
+
+    _LIBCPP_INLINE_VISIBILITY explicit raw_storage_iterator(_OutputIterator __x) : __x_(__x) {}
+    _LIBCPP_INLINE_VISIBILITY raw_storage_iterator& operator*() {return *this;}
+    _LIBCPP_INLINE_VISIBILITY raw_storage_iterator& operator=(const _Tp& __element)
+        {::new ((void*)_VSTD::addressof(*__x_)) _Tp(__element); return *this;}
+#if _LIBCPP_STD_VER >= 14
+    _LIBCPP_INLINE_VISIBILITY raw_storage_iterator& operator=(_Tp&& __element)
+        {::new ((void*)_VSTD::addressof(*__x_)) _Tp(_VSTD::move(__element)); return *this;}
+#endif
+    _LIBCPP_INLINE_VISIBILITY raw_storage_iterator& operator++() {++__x_; return *this;}
+    _LIBCPP_INLINE_VISIBILITY raw_storage_iterator  operator++(int)
+        {raw_storage_iterator __t(*this); ++__x_; return __t;}
+#if _LIBCPP_STD_VER >= 14
+    _LIBCPP_INLINE_VISIBILITY _OutputIterator base() const { return __x_; }
+#endif
+};
+
+#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_RAW_STORAGE_ITERATOR)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_RAW_STORAGE_ITERATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/shared_ptr.h b/contrib/libs/cxxsupp/libcxx/include/__memory/shared_ptr.h
new file mode 100644
index 00000000000..6d844760c82
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/shared_ptr.h
@@ -0,0 +1,1903 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_SHARED_PTR_H
+#define _LIBCPP___MEMORY_SHARED_PTR_H
+
+#include <__availability>
+#include <__config>
+#include <__functional_base>
+#include <__functional/binary_function.h>
+#include <__functional/operations.h>
+#include <__functional/reference_wrapper.h>
+#include <__memory/addressof.h>
+#include <__memory/allocation_guard.h>
+#include <__memory/allocator_traits.h>
+#include <__memory/allocator.h>
+#include <__memory/compressed_pair.h>
+#include <__memory/pointer_traits.h>
+#include <__memory/unique_ptr.h>
+#include <__utility/forward.h>
+#include <cstddef>
+#include <cstdlib> // abort
+#include <iosfwd>
+#include <stdexcept>
+#include <typeinfo>
+#include <type_traits>
+#include <utility>
+#if !defined(_LIBCPP_HAS_NO_THREADS) //!defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
+#  include <atomic>
+#endif
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR)
+#   include <__memory/auto_ptr.h>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Alloc>
+class __allocator_destructor
+{
+    typedef _LIBCPP_NODEBUG allocator_traits<_Alloc> __alloc_traits;
+public:
+    typedef _LIBCPP_NODEBUG typename __alloc_traits::pointer pointer;
+    typedef _LIBCPP_NODEBUG typename __alloc_traits::size_type size_type;
+private:
+    _Alloc& __alloc_;
+    size_type __s_;
+public:
+    _LIBCPP_INLINE_VISIBILITY __allocator_destructor(_Alloc& __a, size_type __s)
+             _NOEXCEPT
+        : __alloc_(__a), __s_(__s) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void operator()(pointer __p) _NOEXCEPT
+        {__alloc_traits::deallocate(__alloc_, __p, __s_);}
+};
+
+// NOTE: Relaxed and acq/rel atomics (for increment and decrement respectively)
+// should be sufficient for thread safety.
+// See https://llvm.org/PR22803
+#if defined(__clang__) && __has_builtin(__atomic_add_fetch)          \
+                       && defined(__ATOMIC_RELAXED)                  \
+                       && defined(__ATOMIC_ACQ_REL)
+#   define _LIBCPP_HAS_BUILTIN_ATOMIC_SUPPORT
+#elif defined(_LIBCPP_COMPILER_GCC)
+#   define _LIBCPP_HAS_BUILTIN_ATOMIC_SUPPORT
+#endif
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+_ValueType __libcpp_relaxed_load(_ValueType const* __value) {
+#if !defined(_LIBCPP_HAS_NO_THREADS) && \
+    defined(__ATOMIC_RELAXED) &&        \
+    (__has_builtin(__atomic_load_n) || defined(_LIBCPP_COMPILER_GCC))
+    return __atomic_load_n(__value, __ATOMIC_RELAXED);
+#else
+    return *__value;
+#endif
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+_ValueType __libcpp_acquire_load(_ValueType const* __value) {
+#if !defined(_LIBCPP_HAS_NO_THREADS) && \
+    defined(__ATOMIC_ACQUIRE) &&        \
+    (__has_builtin(__atomic_load_n) || defined(_LIBCPP_COMPILER_GCC))
+    return __atomic_load_n(__value, __ATOMIC_ACQUIRE);
+#else
+    return *__value;
+#endif
+}
+
+#ifndef _LIBCPP_COMPILER_MSVC
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _Tp
+__libcpp_atomic_refcount_increment(_Tp& __t) _NOEXCEPT
+{
+#if defined(_LIBCPP_HAS_BUILTIN_ATOMIC_SUPPORT) && !defined(_LIBCPP_HAS_NO_THREADS)
+    return __atomic_add_fetch(&__t, 1, __ATOMIC_RELAXED);
+#else
+    return __t += 1;
+#endif
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _Tp
+__libcpp_atomic_refcount_decrement(_Tp& __t) _NOEXCEPT
+{
+#if defined(_LIBCPP_HAS_BUILTIN_ATOMIC_SUPPORT) && !defined(_LIBCPP_HAS_NO_THREADS)
+    return __atomic_add_fetch(&__t, -1, __ATOMIC_ACQ_REL);
+#else
+    return __t -= 1;
+#endif
+}
+#endif
+
+class _LIBCPP_EXCEPTION_ABI bad_weak_ptr
+    : public std::exception
+{
+public:
+    bad_weak_ptr() _NOEXCEPT = default;
+    bad_weak_ptr(const bad_weak_ptr&) _NOEXCEPT = default;
+    virtual ~bad_weak_ptr() _NOEXCEPT;
+    virtual const char* what() const  _NOEXCEPT;
+};
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+void __throw_bad_weak_ptr()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw bad_weak_ptr();
+#else
+    _VSTD::abort();
+#endif
+}
+
+template<class _Tp> class _LIBCPP_TEMPLATE_VIS weak_ptr;
+
+class _LIBCPP_TYPE_VIS __shared_count
+{
+    __shared_count(const __shared_count&);
+    __shared_count& operator=(const __shared_count&);
+
+protected:
+#ifdef _LIBCPP_HAS_NO_THREADS
+    typedef long __atomic_count;
+#else
+    typedef atomic<long> __atomic_count;
+#endif
+    __atomic_count __shared_owners_;
+
+    virtual ~__shared_count();
+private:
+    virtual void __on_zero_shared() _NOEXCEPT = 0;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __shared_count(long __refs = 0) _NOEXCEPT
+        : __shared_owners_(__refs) {}
+
+#if defined(_LIBCPP_BUILDING_LIBRARY) && \
+    defined(_LIBCPP_DEPRECATED_ABI_LEGACY_LIBRARY_DEFINITIONS_FOR_INLINE_FUNCTIONS)
+    void __add_shared() _NOEXCEPT;
+    bool __release_shared() _NOEXCEPT;
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    void __add_shared() _NOEXCEPT {
+#ifdef _LIBCPP_HAS_NO_THREADS
+      __libcpp_atomic_refcount_increment(__shared_owners_);
+#else
+      __shared_owners_++;
+#endif
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    bool __release_shared() _NOEXCEPT {
+#ifdef _LIBCPP_HAS_NO_THREADS
+      if (__libcpp_atomic_refcount_decrement(__shared_owners_) == -1) {
+#else
+      if (--__shared_owners_ == -1) {
+#endif
+        __on_zero_shared();
+        return true;
+      }
+      return false;
+    }
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    long use_count() const _NOEXCEPT {
+#ifdef _LIBCPP_HAS_NO_THREADS
+        return __libcpp_relaxed_load(&__shared_owners_) + 1;
+#else
+        return __shared_owners_.load(memory_order_relaxed) + 1;
+#endif
+    }
+};
+
+class _LIBCPP_TYPE_VIS __shared_weak_count
+    : private __shared_count
+{
+#ifdef _LIBCPP_HAS_NO_THREADS
+    typedef long __atomic_count;
+#else
+    typedef atomic<long> __atomic_count;
+#endif
+    __atomic_count __shared_weak_owners_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __shared_weak_count(long __refs = 0) _NOEXCEPT
+        : __shared_count(__refs),
+          __shared_weak_owners_(__refs) {}
+protected:
+    virtual ~__shared_weak_count();
+
+public:
+#if defined(_LIBCPP_BUILDING_LIBRARY) && \
+    defined(_LIBCPP_DEPRECATED_ABI_LEGACY_LIBRARY_DEFINITIONS_FOR_INLINE_FUNCTIONS)
+    void __add_shared() _NOEXCEPT;
+    void __add_weak() _NOEXCEPT;
+    void __release_shared() _NOEXCEPT;
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    void __add_shared() _NOEXCEPT {
+      __shared_count::__add_shared();
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    void __add_weak() _NOEXCEPT {
+#ifdef _LIBCPP_HAS_NO_THREADS
+      __libcpp_atomic_refcount_increment(__shared_weak_owners_);
+#else
+      __shared_weak_owners_++;
+#endif
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    void __release_shared() _NOEXCEPT {
+      if (__shared_count::__release_shared())
+        __release_weak();
+    }
+#endif
+    void __release_weak() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    long use_count() const _NOEXCEPT {return __shared_count::use_count();}
+    __shared_weak_count* lock() _NOEXCEPT;
+
+    virtual const void* __get_deleter(const type_info&) const _NOEXCEPT;
+private:
+    virtual void __on_zero_shared_weak() _NOEXCEPT = 0;
+};
+
+template <class _Tp, class _Dp, class _Alloc>
+class __shared_ptr_pointer
+    : public __shared_weak_count
+{
+    __compressed_pair<__compressed_pair<_Tp, _Dp>, _Alloc> __data_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __shared_ptr_pointer(_Tp __p, _Dp __d, _Alloc __a)
+        :  __data_(__compressed_pair<_Tp, _Dp>(__p, _VSTD::move(__d)), _VSTD::move(__a)) {}
+
+#ifndef _LIBCPP_NO_RTTI
+    virtual const void* __get_deleter(const type_info&) const _NOEXCEPT;
+#endif
+
+private:
+    virtual void __on_zero_shared() _NOEXCEPT;
+    virtual void __on_zero_shared_weak() _NOEXCEPT;
+};
+
+#ifndef _LIBCPP_NO_RTTI
+
+template <class _Tp, class _Dp, class _Alloc>
+const void*
+__shared_ptr_pointer<_Tp, _Dp, _Alloc>::__get_deleter(const type_info& __t) const _NOEXCEPT
+{
+    return __t == typeid(_Dp) ? _VSTD::addressof(__data_.first().second()) : nullptr;
+}
+
+#endif // _LIBCPP_NO_RTTI
+
+template <class _Tp, class _Dp, class _Alloc>
+void
+__shared_ptr_pointer<_Tp, _Dp, _Alloc>::__on_zero_shared() _NOEXCEPT
+{
+    __data_.first().second()(__data_.first().first());
+    __data_.first().second().~_Dp();
+}
+
+template <class _Tp, class _Dp, class _Alloc>
+void
+__shared_ptr_pointer<_Tp, _Dp, _Alloc>::__on_zero_shared_weak() _NOEXCEPT
+{
+    typedef typename __allocator_traits_rebind<_Alloc, __shared_ptr_pointer>::type _Al;
+    typedef allocator_traits<_Al> _ATraits;
+    typedef pointer_traits<typename _ATraits::pointer> _PTraits;
+
+    _Al __a(__data_.second());
+    __data_.second().~_Alloc();
+    __a.deallocate(_PTraits::pointer_to(*this), 1);
+}
+
+template <class _Tp, class _Alloc>
+struct __shared_ptr_emplace
+    : __shared_weak_count
+{
+    template<class ..._Args>
+    _LIBCPP_HIDE_FROM_ABI
+    explicit __shared_ptr_emplace(_Alloc __a, _Args&& ...__args)
+        : __storage_(_VSTD::move(__a))
+    {
+#if _LIBCPP_STD_VER > 17
+        using _TpAlloc = typename __allocator_traits_rebind<_Alloc, _Tp>::type;
+        _TpAlloc __tmp(*__get_alloc());
+        allocator_traits<_TpAlloc>::construct(__tmp, __get_elem(), _VSTD::forward<_Args>(__args)...);
+#else
+        ::new ((void*)__get_elem()) _Tp(_VSTD::forward<_Args>(__args)...);
+#endif
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    _Alloc* __get_alloc() _NOEXCEPT { return __storage_.__get_alloc(); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    _Tp* __get_elem() _NOEXCEPT { return __storage_.__get_elem(); }
+
+private:
+    virtual void __on_zero_shared() _NOEXCEPT {
+#if _LIBCPP_STD_VER > 17
+        using _TpAlloc = typename __allocator_traits_rebind<_Alloc, _Tp>::type;
+        _TpAlloc __tmp(*__get_alloc());
+        allocator_traits<_TpAlloc>::destroy(__tmp, __get_elem());
+#else
+        __get_elem()->~_Tp();
+#endif
+    }
+
+    virtual void __on_zero_shared_weak() _NOEXCEPT {
+        using _ControlBlockAlloc = typename __allocator_traits_rebind<_Alloc, __shared_ptr_emplace>::type;
+        using _ControlBlockPointer = typename allocator_traits<_ControlBlockAlloc>::pointer;
+        _ControlBlockAlloc __tmp(*__get_alloc());
+        __storage_.~_Storage();
+        allocator_traits<_ControlBlockAlloc>::deallocate(__tmp,
+            pointer_traits<_ControlBlockPointer>::pointer_to(*this), 1);
+    }
+
+    // This class implements the control block for non-array shared pointers created
+    // through `std::allocate_shared` and `std::make_shared`.
+    //
+    // In previous versions of the library, we used a compressed pair to store
+    // both the _Alloc and the _Tp. This implies using EBO, which is incompatible
+    // with Allocator construction for _Tp. To allow implementing P0674 in C++20,
+    // we now use a properly aligned char buffer while making sure that we maintain
+    // the same layout that we had when we used a compressed pair.
+    using _CompressedPair = __compressed_pair<_Alloc, _Tp>;
+    struct _ALIGNAS_TYPE(_CompressedPair) _Storage {
+        char __blob_[sizeof(_CompressedPair)];
+
+        _LIBCPP_HIDE_FROM_ABI explicit _Storage(_Alloc&& __a) {
+            ::new ((void*)__get_alloc()) _Alloc(_VSTD::move(__a));
+        }
+        _LIBCPP_HIDE_FROM_ABI ~_Storage() {
+            __get_alloc()->~_Alloc();
+        }
+        _Alloc* __get_alloc() _NOEXCEPT {
+            _CompressedPair *__as_pair = reinterpret_cast<_CompressedPair*>(__blob_);
+            typename _CompressedPair::_Base1* __first = _CompressedPair::__get_first_base(__as_pair);
+            _Alloc *__alloc = reinterpret_cast<_Alloc*>(__first);
+            return __alloc;
+        }
+        _LIBCPP_NO_CFI _Tp* __get_elem() _NOEXCEPT {
+            _CompressedPair *__as_pair = reinterpret_cast<_CompressedPair*>(__blob_);
+            typename _CompressedPair::_Base2* __second = _CompressedPair::__get_second_base(__as_pair);
+            _Tp *__elem = reinterpret_cast<_Tp*>(__second);
+            return __elem;
+        }
+    };
+
+    static_assert(_LIBCPP_ALIGNOF(_Storage) == _LIBCPP_ALIGNOF(_CompressedPair), "");
+    static_assert(sizeof(_Storage) == sizeof(_CompressedPair), "");
+    _Storage __storage_;
+};
+
+struct __shared_ptr_dummy_rebind_allocator_type;
+template <>
+class _LIBCPP_TEMPLATE_VIS allocator<__shared_ptr_dummy_rebind_allocator_type>
+{
+public:
+    template <class _Other>
+    struct rebind
+    {
+        typedef allocator<_Other> other;
+    };
+};
+
+template<class _Tp> class _LIBCPP_TEMPLATE_VIS enable_shared_from_this;
+
+template<class _Tp, class _Up>
+struct __compatible_with
+#if _LIBCPP_STD_VER > 14
+    : is_convertible<remove_extent_t<_Tp>*, remove_extent_t<_Up>*> {};
+#else
+    : is_convertible<_Tp*, _Up*> {};
+#endif // _LIBCPP_STD_VER > 14
+
+template <class _Ptr, class = void>
+struct __is_deletable : false_type { };
+template <class _Ptr>
+struct __is_deletable<_Ptr, decltype(delete declval<_Ptr>())> : true_type { };
+
+template <class _Ptr, class = void>
+struct __is_array_deletable : false_type { };
+template <class _Ptr>
+struct __is_array_deletable<_Ptr, decltype(delete[] declval<_Ptr>())> : true_type { };
+
+template <class _Dp, class _Pt,
+    class = decltype(declval<_Dp>()(declval<_Pt>()))>
+static true_type __well_formed_deleter_test(int);
+
+template <class, class>
+static false_type __well_formed_deleter_test(...);
+
+template <class _Dp, class _Pt>
+struct __well_formed_deleter : decltype(__well_formed_deleter_test<_Dp, _Pt>(0)) {};
+
+template<class _Dp, class _Tp, class _Yp>
+struct __shared_ptr_deleter_ctor_reqs
+{
+    static const bool value = __compatible_with<_Tp, _Yp>::value &&
+                              is_move_constructible<_Dp>::value &&
+                              __well_formed_deleter<_Dp, _Tp*>::value;
+};
+
+#if defined(_LIBCPP_ABI_ENABLE_SHARED_PTR_TRIVIAL_ABI)
+#  define _LIBCPP_SHARED_PTR_TRIVIAL_ABI __attribute__((trivial_abi))
+#else
+#  define _LIBCPP_SHARED_PTR_TRIVIAL_ABI
+#endif
+
+template<class _Tp>
+class _LIBCPP_SHARED_PTR_TRIVIAL_ABI _LIBCPP_TEMPLATE_VIS shared_ptr
+{
+public:
+#if _LIBCPP_STD_VER > 14
+    typedef weak_ptr<_Tp> weak_type;
+    typedef remove_extent_t<_Tp> element_type;
+#else
+    typedef _Tp element_type;
+#endif
+
+private:
+    element_type*      __ptr_;
+    __shared_weak_count* __cntrl_;
+
+    struct __nat {int __for_bool_;};
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR shared_ptr() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR shared_ptr(nullptr_t) _NOEXCEPT;
+
+    template<class _Yp, class = __enable_if_t<
+        _And<
+            __compatible_with<_Yp, _Tp>
+            // In C++03 we get errors when trying to do SFINAE with the
+            // delete operator, so we always pretend that it's deletable.
+            // The same happens on GCC.
+#if !defined(_LIBCPP_CXX03_LANG) && !defined(_LIBCPP_COMPILER_GCC)
+            , _If<is_array<_Tp>::value, __is_array_deletable<_Yp*>, __is_deletable<_Yp*> >
+#endif
+        >::value
+    > >
+    explicit shared_ptr(_Yp* __p) : __ptr_(__p) {
+        unique_ptr<_Yp> __hold(__p);
+        typedef typename __shared_ptr_default_allocator<_Yp>::type _AllocT;
+        typedef __shared_ptr_pointer<_Yp*, __shared_ptr_default_delete<_Tp, _Yp>, _AllocT > _CntrlBlk;
+        __cntrl_ = new _CntrlBlk(__p, __shared_ptr_default_delete<_Tp, _Yp>(), _AllocT());
+        __hold.release();
+        __enable_weak_this(__p, __p);
+    }
+
+    template<class _Yp, class _Dp>
+        shared_ptr(_Yp* __p, _Dp __d,
+                   typename enable_if<__shared_ptr_deleter_ctor_reqs<_Dp, _Yp, element_type>::value, __nat>::type = __nat());
+    template<class _Yp, class _Dp, class _Alloc>
+        shared_ptr(_Yp* __p, _Dp __d, _Alloc __a,
+                   typename enable_if<__shared_ptr_deleter_ctor_reqs<_Dp, _Yp, element_type>::value, __nat>::type = __nat());
+    template <class _Dp> shared_ptr(nullptr_t __p, _Dp __d);
+    template <class _Dp, class _Alloc> shared_ptr(nullptr_t __p, _Dp __d, _Alloc __a);
+    template<class _Yp> _LIBCPP_INLINE_VISIBILITY shared_ptr(const shared_ptr<_Yp>& __r, element_type* __p) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    shared_ptr(const shared_ptr& __r) _NOEXCEPT;
+    template<class _Yp>
+        _LIBCPP_INLINE_VISIBILITY
+        shared_ptr(const shared_ptr<_Yp>& __r,
+                   typename enable_if<__compatible_with<_Yp, element_type>::value, __nat>::type = __nat())
+                       _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    shared_ptr(shared_ptr&& __r) _NOEXCEPT;
+    template<class _Yp> _LIBCPP_INLINE_VISIBILITY  shared_ptr(shared_ptr<_Yp>&& __r,
+                   typename enable_if<__compatible_with<_Yp, element_type>::value, __nat>::type = __nat())
+                       _NOEXCEPT;
+    template<class _Yp> explicit shared_ptr(const weak_ptr<_Yp>& __r,
+                   typename enable_if<is_convertible<_Yp*, element_type*>::value, __nat>::type= __nat());
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR)
+    template<class _Yp>
+        shared_ptr(auto_ptr<_Yp>&& __r,
+                   typename enable_if<is_convertible<_Yp*, element_type*>::value, __nat>::type = __nat());
+#endif
+    template <class _Yp, class _Dp>
+        shared_ptr(unique_ptr<_Yp, _Dp>&&,
+                   typename enable_if
+                   <
+                       !is_lvalue_reference<_Dp>::value &&
+                       is_convertible<typename unique_ptr<_Yp, _Dp>::pointer, element_type*>::value,
+                       __nat
+                   >::type = __nat());
+    template <class _Yp, class _Dp>
+        shared_ptr(unique_ptr<_Yp, _Dp>&&,
+                   typename enable_if
+                   <
+                       is_lvalue_reference<_Dp>::value &&
+                       is_convertible<typename unique_ptr<_Yp, _Dp>::pointer, element_type*>::value,
+                       __nat
+                   >::type = __nat());
+
+    ~shared_ptr();
+
+    _LIBCPP_INLINE_VISIBILITY
+    shared_ptr& operator=(const shared_ptr& __r) _NOEXCEPT;
+    template<class _Yp>
+        typename enable_if
+        <
+            __compatible_with<_Yp, typename _VSTD::shared_ptr<_Tp>::element_type>::value,
+            shared_ptr&
+        >::type
+        _LIBCPP_INLINE_VISIBILITY
+        operator=(const shared_ptr<_Yp>& __r) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    shared_ptr& operator=(shared_ptr&& __r) _NOEXCEPT;
+    template<class _Yp>
+        typename enable_if
+        <
+            __compatible_with<_Yp, typename _VSTD::shared_ptr<_Tp>::element_type>::value,
+            shared_ptr&
+        >::type
+        _LIBCPP_INLINE_VISIBILITY
+        operator=(shared_ptr<_Yp>&& __r);
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR)
+    template<class _Yp>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            !is_array<_Yp>::value &&
+            is_convertible<_Yp*, typename _VSTD::shared_ptr<_Tp>::element_type*>::value,
+            shared_ptr
+        >::type&
+        operator=(auto_ptr<_Yp>&& __r);
+#endif
+    template <class _Yp, class _Dp>
+        typename enable_if
+        <
+            is_convertible<typename unique_ptr<_Yp, _Dp>::pointer, typename _VSTD::shared_ptr<_Tp>::element_type*>::value,
+            shared_ptr&
+        >::type
+        _LIBCPP_INLINE_VISIBILITY
+        operator=(unique_ptr<_Yp, _Dp>&& __r);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(shared_ptr& __r) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() _NOEXCEPT;
+    template<class _Yp>
+        typename enable_if
+        <
+            __compatible_with<_Yp, typename _VSTD::shared_ptr<_Tp>::element_type>::value,
+            void
+        >::type
+        _LIBCPP_INLINE_VISIBILITY
+        reset(_Yp* __p);
+    template<class _Yp, class _Dp>
+        typename enable_if
+        <
+            __compatible_with<_Yp, typename _VSTD::shared_ptr<_Tp>::element_type>::value,
+            void
+        >::type
+        _LIBCPP_INLINE_VISIBILITY
+        reset(_Yp* __p, _Dp __d);
+    template<class _Yp, class _Dp, class _Alloc>
+        typename enable_if
+        <
+            __compatible_with<_Yp, typename _VSTD::shared_ptr<_Tp>::element_type>::value,
+            void
+        >::type
+        _LIBCPP_INLINE_VISIBILITY
+        reset(_Yp* __p, _Dp __d, _Alloc __a);
+
+    _LIBCPP_INLINE_VISIBILITY
+    element_type* get() const _NOEXCEPT {return __ptr_;}
+    _LIBCPP_INLINE_VISIBILITY
+    typename add_lvalue_reference<element_type>::type operator*() const _NOEXCEPT
+        {return *__ptr_;}
+    _LIBCPP_INLINE_VISIBILITY
+    element_type* operator->() const _NOEXCEPT
+    {
+        static_assert(!is_array<_Tp>::value,
+                      "std::shared_ptr<T>::operator-> is only valid when T is not an array type.");
+        return __ptr_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    long use_count() const _NOEXCEPT {return __cntrl_ ? __cntrl_->use_count() : 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    bool unique() const _NOEXCEPT {return use_count() == 1;}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit operator bool() const _NOEXCEPT {return get() != nullptr;}
+    template <class _Up>
+        _LIBCPP_INLINE_VISIBILITY
+        bool owner_before(shared_ptr<_Up> const& __p) const _NOEXCEPT
+        {return __cntrl_ < __p.__cntrl_;}
+    template <class _Up>
+        _LIBCPP_INLINE_VISIBILITY
+        bool owner_before(weak_ptr<_Up> const& __p) const _NOEXCEPT
+        {return __cntrl_ < __p.__cntrl_;}
+    _LIBCPP_INLINE_VISIBILITY
+    bool
+    __owner_equivalent(const shared_ptr& __p) const
+        {return __cntrl_ == __p.__cntrl_;}
+
+#if _LIBCPP_STD_VER > 14
+    typename add_lvalue_reference<element_type>::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator[](ptrdiff_t __i) const
+    {
+            static_assert(is_array<_Tp>::value,
+                          "std::shared_ptr<T>::operator[] is only valid when T is an array type.");
+            return __ptr_[__i];
+    }
+#endif
+
+#ifndef _LIBCPP_NO_RTTI
+    template <class _Dp>
+        _LIBCPP_INLINE_VISIBILITY
+        _Dp* __get_deleter() const _NOEXCEPT
+            {return static_cast<_Dp*>(__cntrl_
+                    ? const_cast<void *>(__cntrl_->__get_deleter(typeid(_Dp)))
+                      : nullptr);}
+#endif // _LIBCPP_NO_RTTI
+
+    template<class _Yp, class _CntrlBlk>
+    static shared_ptr<_Tp>
+    __create_with_control_block(_Yp* __p, _CntrlBlk* __cntrl) _NOEXCEPT
+    {
+        shared_ptr<_Tp> __r;
+        __r.__ptr_ = __p;
+        __r.__cntrl_ = __cntrl;
+        __r.__enable_weak_this(__r.__ptr_, __r.__ptr_);
+        return __r;
+    }
+
+private:
+    template <class _Yp, bool = is_function<_Yp>::value>
+        struct __shared_ptr_default_allocator
+        {
+            typedef allocator<_Yp> type;
+        };
+
+    template <class _Yp>
+        struct __shared_ptr_default_allocator<_Yp, true>
+        {
+            typedef allocator<__shared_ptr_dummy_rebind_allocator_type> type;
+        };
+
+    template <class _Yp, class _OrigPtr>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if<is_convertible<_OrigPtr*,
+                                          const enable_shared_from_this<_Yp>*
+        >::value,
+            void>::type
+        __enable_weak_this(const enable_shared_from_this<_Yp>* __e,
+                           _OrigPtr* __ptr) _NOEXCEPT
+        {
+            typedef typename remove_cv<_Yp>::type _RawYp;
+            if (__e && __e->__weak_this_.expired())
+            {
+                __e->__weak_this_ = shared_ptr<_RawYp>(*this,
+                    const_cast<_RawYp*>(static_cast<const _Yp*>(__ptr)));
+            }
+        }
+
+    _LIBCPP_INLINE_VISIBILITY void __enable_weak_this(...) _NOEXCEPT {}
+
+    template <class, class _Yp>
+        struct __shared_ptr_default_delete
+            : default_delete<_Yp> {};
+
+    template <class _Yp, class _Un, size_t _Sz>
+        struct __shared_ptr_default_delete<_Yp[_Sz], _Un>
+            : default_delete<_Yp[]> {};
+
+    template <class _Yp, class _Un>
+        struct __shared_ptr_default_delete<_Yp[], _Un>
+            : default_delete<_Yp[]> {};
+
+    template <class _Up> friend class _LIBCPP_TEMPLATE_VIS shared_ptr;
+    template <class _Up> friend class _LIBCPP_TEMPLATE_VIS weak_ptr;
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _Tp>
+shared_ptr(weak_ptr<_Tp>) -> shared_ptr<_Tp>;
+template<class _Tp, class _Dp>
+shared_ptr(unique_ptr<_Tp, _Dp>) -> shared_ptr<_Tp>;
+#endif
+
+template<class _Tp>
+inline
+_LIBCPP_CONSTEXPR
+shared_ptr<_Tp>::shared_ptr() _NOEXCEPT
+    : __ptr_(nullptr),
+      __cntrl_(nullptr)
+{
+}
+
+template<class _Tp>
+inline
+_LIBCPP_CONSTEXPR
+shared_ptr<_Tp>::shared_ptr(nullptr_t) _NOEXCEPT
+    : __ptr_(nullptr),
+      __cntrl_(nullptr)
+{
+}
+
+template<class _Tp>
+template<class _Yp, class _Dp>
+shared_ptr<_Tp>::shared_ptr(_Yp* __p, _Dp __d,
+                            typename enable_if<__shared_ptr_deleter_ctor_reqs<_Dp, _Yp, element_type>::value, __nat>::type)
+    : __ptr_(__p)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        typedef typename __shared_ptr_default_allocator<_Yp>::type _AllocT;
+        typedef __shared_ptr_pointer<_Yp*, _Dp, _AllocT > _CntrlBlk;
+#ifndef _LIBCPP_CXX03_LANG
+        __cntrl_ = new _CntrlBlk(__p, _VSTD::move(__d), _AllocT());
+#else
+        __cntrl_ = new _CntrlBlk(__p, __d, _AllocT());
+#endif // not _LIBCPP_CXX03_LANG
+        __enable_weak_this(__p, __p);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __d(__p);
+        throw;
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template<class _Tp>
+template<class _Dp>
+shared_ptr<_Tp>::shared_ptr(nullptr_t __p, _Dp __d)
+    : __ptr_(nullptr)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        typedef typename __shared_ptr_default_allocator<_Tp>::type _AllocT;
+        typedef __shared_ptr_pointer<nullptr_t, _Dp, _AllocT > _CntrlBlk;
+#ifndef _LIBCPP_CXX03_LANG
+        __cntrl_ = new _CntrlBlk(__p, _VSTD::move(__d), _AllocT());
+#else
+        __cntrl_ = new _CntrlBlk(__p, __d, _AllocT());
+#endif // not _LIBCPP_CXX03_LANG
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __d(__p);
+        throw;
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template<class _Tp>
+template<class _Yp, class _Dp, class _Alloc>
+shared_ptr<_Tp>::shared_ptr(_Yp* __p, _Dp __d, _Alloc __a,
+                            typename enable_if<__shared_ptr_deleter_ctor_reqs<_Dp, _Yp, element_type>::value, __nat>::type)
+    : __ptr_(__p)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        typedef __shared_ptr_pointer<_Yp*, _Dp, _Alloc> _CntrlBlk;
+        typedef typename __allocator_traits_rebind<_Alloc, _CntrlBlk>::type _A2;
+        typedef __allocator_destructor<_A2> _D2;
+        _A2 __a2(__a);
+        unique_ptr<_CntrlBlk, _D2> __hold2(__a2.allocate(1), _D2(__a2, 1));
+        ::new ((void*)_VSTD::addressof(*__hold2.get()))
+#ifndef _LIBCPP_CXX03_LANG
+            _CntrlBlk(__p, _VSTD::move(__d), __a);
+#else
+            _CntrlBlk(__p, __d, __a);
+#endif // not _LIBCPP_CXX03_LANG
+        __cntrl_ = _VSTD::addressof(*__hold2.release());
+        __enable_weak_this(__p, __p);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __d(__p);
+        throw;
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template<class _Tp>
+template<class _Dp, class _Alloc>
+shared_ptr<_Tp>::shared_ptr(nullptr_t __p, _Dp __d, _Alloc __a)
+    : __ptr_(nullptr)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        typedef __shared_ptr_pointer<nullptr_t, _Dp, _Alloc> _CntrlBlk;
+        typedef typename __allocator_traits_rebind<_Alloc, _CntrlBlk>::type _A2;
+        typedef __allocator_destructor<_A2> _D2;
+        _A2 __a2(__a);
+        unique_ptr<_CntrlBlk, _D2> __hold2(__a2.allocate(1), _D2(__a2, 1));
+        ::new ((void*)_VSTD::addressof(*__hold2.get()))
+#ifndef _LIBCPP_CXX03_LANG
+            _CntrlBlk(__p, _VSTD::move(__d), __a);
+#else
+            _CntrlBlk(__p, __d, __a);
+#endif // not _LIBCPP_CXX03_LANG
+        __cntrl_ = _VSTD::addressof(*__hold2.release());
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __d(__p);
+        throw;
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template<class _Tp>
+template<class _Yp>
+inline
+shared_ptr<_Tp>::shared_ptr(const shared_ptr<_Yp>& __r, element_type *__p) _NOEXCEPT
+    : __ptr_(__p),
+      __cntrl_(__r.__cntrl_)
+{
+    if (__cntrl_)
+        __cntrl_->__add_shared();
+}
+
+template<class _Tp>
+inline
+shared_ptr<_Tp>::shared_ptr(const shared_ptr& __r) _NOEXCEPT
+    : __ptr_(__r.__ptr_),
+      __cntrl_(__r.__cntrl_)
+{
+    if (__cntrl_)
+        __cntrl_->__add_shared();
+}
+
+template<class _Tp>
+template<class _Yp>
+inline
+shared_ptr<_Tp>::shared_ptr(const shared_ptr<_Yp>& __r,
+                            typename enable_if<__compatible_with<_Yp, element_type>::value, __nat>::type)
+         _NOEXCEPT
+    : __ptr_(__r.__ptr_),
+      __cntrl_(__r.__cntrl_)
+{
+    if (__cntrl_)
+        __cntrl_->__add_shared();
+}
+
+template<class _Tp>
+inline
+shared_ptr<_Tp>::shared_ptr(shared_ptr&& __r) _NOEXCEPT
+    : __ptr_(__r.__ptr_),
+      __cntrl_(__r.__cntrl_)
+{
+    __r.__ptr_ = nullptr;
+    __r.__cntrl_ = nullptr;
+}
+
+template<class _Tp>
+template<class _Yp>
+inline
+shared_ptr<_Tp>::shared_ptr(shared_ptr<_Yp>&& __r,
+                            typename enable_if<__compatible_with<_Yp, element_type>::value, __nat>::type)
+         _NOEXCEPT
+    : __ptr_(__r.__ptr_),
+      __cntrl_(__r.__cntrl_)
+{
+    __r.__ptr_ = nullptr;
+    __r.__cntrl_ = nullptr;
+}
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR)
+template<class _Tp>
+template<class _Yp>
+shared_ptr<_Tp>::shared_ptr(auto_ptr<_Yp>&& __r,
+                            typename enable_if<is_convertible<_Yp*, element_type*>::value, __nat>::type)
+    : __ptr_(__r.get())
+{
+    typedef __shared_ptr_pointer<_Yp*, default_delete<_Yp>, allocator<_Yp> > _CntrlBlk;
+    __cntrl_ = new _CntrlBlk(__r.get(), default_delete<_Yp>(), allocator<_Yp>());
+    __enable_weak_this(__r.get(), __r.get());
+    __r.release();
+}
+#endif
+
+template<class _Tp>
+template <class _Yp, class _Dp>
+shared_ptr<_Tp>::shared_ptr(unique_ptr<_Yp, _Dp>&& __r,
+                            typename enable_if
+                            <
+                                !is_lvalue_reference<_Dp>::value &&
+                                is_convertible<typename unique_ptr<_Yp, _Dp>::pointer, element_type*>::value,
+                                __nat
+                            >::type)
+    : __ptr_(__r.get())
+{
+#if _LIBCPP_STD_VER > 11
+    if (__ptr_ == nullptr)
+        __cntrl_ = nullptr;
+    else
+#endif
+    {
+        typedef typename __shared_ptr_default_allocator<_Yp>::type _AllocT;
+        typedef __shared_ptr_pointer<typename unique_ptr<_Yp, _Dp>::pointer, _Dp, _AllocT > _CntrlBlk;
+        __cntrl_ = new _CntrlBlk(__r.get(), __r.get_deleter(), _AllocT());
+        __enable_weak_this(__r.get(), __r.get());
+    }
+    __r.release();
+}
+
+template<class _Tp>
+template <class _Yp, class _Dp>
+shared_ptr<_Tp>::shared_ptr(unique_ptr<_Yp, _Dp>&& __r,
+                            typename enable_if
+                            <
+                                is_lvalue_reference<_Dp>::value &&
+                                is_convertible<typename unique_ptr<_Yp, _Dp>::pointer, element_type*>::value,
+                                __nat
+                            >::type)
+    : __ptr_(__r.get())
+{
+#if _LIBCPP_STD_VER > 11
+    if (__ptr_ == nullptr)
+        __cntrl_ = nullptr;
+    else
+#endif
+    {
+        typedef typename __shared_ptr_default_allocator<_Yp>::type _AllocT;
+        typedef __shared_ptr_pointer<typename unique_ptr<_Yp, _Dp>::pointer,
+                                     reference_wrapper<typename remove_reference<_Dp>::type>,
+                                     _AllocT > _CntrlBlk;
+        __cntrl_ = new _CntrlBlk(__r.get(), _VSTD::ref(__r.get_deleter()), _AllocT());
+        __enable_weak_this(__r.get(), __r.get());
+    }
+    __r.release();
+}
+
+template<class _Tp>
+shared_ptr<_Tp>::~shared_ptr()
+{
+    if (__cntrl_)
+        __cntrl_->__release_shared();
+}
+
+template<class _Tp>
+inline
+shared_ptr<_Tp>&
+shared_ptr<_Tp>::operator=(const shared_ptr& __r) _NOEXCEPT
+{
+    shared_ptr(__r).swap(*this);
+    return *this;
+}
+
+template<class _Tp>
+template<class _Yp>
+inline
+typename enable_if
+<
+    __compatible_with<_Yp, typename shared_ptr<_Tp>::element_type>::value,
+    shared_ptr<_Tp>&
+>::type
+shared_ptr<_Tp>::operator=(const shared_ptr<_Yp>& __r) _NOEXCEPT
+{
+    shared_ptr(__r).swap(*this);
+    return *this;
+}
+
+template<class _Tp>
+inline
+shared_ptr<_Tp>&
+shared_ptr<_Tp>::operator=(shared_ptr&& __r) _NOEXCEPT
+{
+    shared_ptr(_VSTD::move(__r)).swap(*this);
+    return *this;
+}
+
+template<class _Tp>
+template<class _Yp>
+inline
+typename enable_if
+<
+    __compatible_with<_Yp, typename shared_ptr<_Tp>::element_type>::value,
+    shared_ptr<_Tp>&
+>::type
+shared_ptr<_Tp>::operator=(shared_ptr<_Yp>&& __r)
+{
+    shared_ptr(_VSTD::move(__r)).swap(*this);
+    return *this;
+}
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR)
+template<class _Tp>
+template<class _Yp>
+inline
+typename enable_if
+<
+    !is_array<_Yp>::value &&
+    is_convertible<_Yp*, typename shared_ptr<_Tp>::element_type*>::value,
+    shared_ptr<_Tp>
+>::type&
+shared_ptr<_Tp>::operator=(auto_ptr<_Yp>&& __r)
+{
+    shared_ptr(_VSTD::move(__r)).swap(*this);
+    return *this;
+}
+#endif
+
+template<class _Tp>
+template <class _Yp, class _Dp>
+inline
+typename enable_if
+<
+    is_convertible<typename unique_ptr<_Yp, _Dp>::pointer,
+                   typename shared_ptr<_Tp>::element_type*>::value,
+    shared_ptr<_Tp>&
+>::type
+shared_ptr<_Tp>::operator=(unique_ptr<_Yp, _Dp>&& __r)
+{
+    shared_ptr(_VSTD::move(__r)).swap(*this);
+    return *this;
+}
+
+template<class _Tp>
+inline
+void
+shared_ptr<_Tp>::swap(shared_ptr& __r) _NOEXCEPT
+{
+    _VSTD::swap(__ptr_, __r.__ptr_);
+    _VSTD::swap(__cntrl_, __r.__cntrl_);
+}
+
+template<class _Tp>
+inline
+void
+shared_ptr<_Tp>::reset() _NOEXCEPT
+{
+    shared_ptr().swap(*this);
+}
+
+template<class _Tp>
+template<class _Yp>
+inline
+typename enable_if
+<
+    __compatible_with<_Yp, typename shared_ptr<_Tp>::element_type>::value,
+    void
+>::type
+shared_ptr<_Tp>::reset(_Yp* __p)
+{
+    shared_ptr(__p).swap(*this);
+}
+
+template<class _Tp>
+template<class _Yp, class _Dp>
+inline
+typename enable_if
+<
+    __compatible_with<_Yp, typename shared_ptr<_Tp>::element_type>::value,
+    void
+>::type
+shared_ptr<_Tp>::reset(_Yp* __p, _Dp __d)
+{
+    shared_ptr(__p, __d).swap(*this);
+}
+
+template<class _Tp>
+template<class _Yp, class _Dp, class _Alloc>
+inline
+typename enable_if
+<
+    __compatible_with<_Yp, typename shared_ptr<_Tp>::element_type>::value,
+    void
+>::type
+shared_ptr<_Tp>::reset(_Yp* __p, _Dp __d, _Alloc __a)
+{
+    shared_ptr(__p, __d, __a).swap(*this);
+}
+
+//
+// std::allocate_shared and std::make_shared
+//
+template<class _Tp, class _Alloc, class ..._Args, class = __enable_if_t<!is_array<_Tp>::value> >
+_LIBCPP_HIDE_FROM_ABI
+shared_ptr<_Tp> allocate_shared(const _Alloc& __a, _Args&& ...__args)
+{
+    using _ControlBlock = __shared_ptr_emplace<_Tp, _Alloc>;
+    using _ControlBlockAllocator = typename __allocator_traits_rebind<_Alloc, _ControlBlock>::type;
+    __allocation_guard<_ControlBlockAllocator> __guard(__a, 1);
+    ::new ((void*)_VSTD::addressof(*__guard.__get())) _ControlBlock(__a, _VSTD::forward<_Args>(__args)...);
+    auto __control_block = __guard.__release_ptr();
+    return shared_ptr<_Tp>::__create_with_control_block((*__control_block).__get_elem(), _VSTD::addressof(*__control_block));
+}
+
+template<class _Tp, class ..._Args, class = __enable_if_t<!is_array<_Tp>::value> >
+_LIBCPP_HIDE_FROM_ABI
+shared_ptr<_Tp> make_shared(_Args&& ...__args)
+{
+    return _VSTD::allocate_shared<_Tp>(allocator<_Tp>(), _VSTD::forward<_Args>(__args)...);
+}
+
+template<class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const shared_ptr<_Tp>& __x, const shared_ptr<_Up>& __y) _NOEXCEPT
+{
+    return __x.get() == __y.get();
+}
+
+template<class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const shared_ptr<_Tp>& __x, const shared_ptr<_Up>& __y) _NOEXCEPT
+{
+    return !(__x == __y);
+}
+
+template<class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(const shared_ptr<_Tp>& __x, const shared_ptr<_Up>& __y) _NOEXCEPT
+{
+#if _LIBCPP_STD_VER <= 11
+    typedef typename common_type<_Tp*, _Up*>::type _Vp;
+    return less<_Vp>()(__x.get(), __y.get());
+#else
+    return less<>()(__x.get(), __y.get());
+#endif
+
+}
+
+template<class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>(const shared_ptr<_Tp>& __x, const shared_ptr<_Up>& __y) _NOEXCEPT
+{
+    return __y < __x;
+}
+
+template<class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const shared_ptr<_Tp>& __x, const shared_ptr<_Up>& __y) _NOEXCEPT
+{
+    return !(__y < __x);
+}
+
+template<class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const shared_ptr<_Tp>& __x, const shared_ptr<_Up>& __y) _NOEXCEPT
+{
+    return !(__x < __y);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const shared_ptr<_Tp>& __x, nullptr_t) _NOEXCEPT
+{
+    return !__x;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(nullptr_t, const shared_ptr<_Tp>& __x) _NOEXCEPT
+{
+    return !__x;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const shared_ptr<_Tp>& __x, nullptr_t) _NOEXCEPT
+{
+    return static_cast<bool>(__x);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(nullptr_t, const shared_ptr<_Tp>& __x) _NOEXCEPT
+{
+    return static_cast<bool>(__x);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(const shared_ptr<_Tp>& __x, nullptr_t) _NOEXCEPT
+{
+    return less<_Tp*>()(__x.get(), nullptr);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(nullptr_t, const shared_ptr<_Tp>& __x) _NOEXCEPT
+{
+    return less<_Tp*>()(nullptr, __x.get());
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>(const shared_ptr<_Tp>& __x, nullptr_t) _NOEXCEPT
+{
+    return nullptr < __x;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>(nullptr_t, const shared_ptr<_Tp>& __x) _NOEXCEPT
+{
+    return __x < nullptr;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const shared_ptr<_Tp>& __x, nullptr_t) _NOEXCEPT
+{
+    return !(nullptr < __x);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(nullptr_t, const shared_ptr<_Tp>& __x) _NOEXCEPT
+{
+    return !(__x < nullptr);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const shared_ptr<_Tp>& __x, nullptr_t) _NOEXCEPT
+{
+    return !(__x < nullptr);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(nullptr_t, const shared_ptr<_Tp>& __x) _NOEXCEPT
+{
+    return !(nullptr < __x);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(shared_ptr<_Tp>& __x, shared_ptr<_Tp>& __y) _NOEXCEPT
+{
+    __x.swap(__y);
+}
+
+template<class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+shared_ptr<_Tp>
+static_pointer_cast(const shared_ptr<_Up>& __r) _NOEXCEPT
+{
+    return shared_ptr<_Tp>(__r,
+                           static_cast<
+                               typename shared_ptr<_Tp>::element_type*>(__r.get()));
+}
+
+template<class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+shared_ptr<_Tp>
+dynamic_pointer_cast(const shared_ptr<_Up>& __r) _NOEXCEPT
+{
+    typedef typename shared_ptr<_Tp>::element_type _ET;
+    _ET* __p = dynamic_cast<_ET*>(__r.get());
+    return __p ? shared_ptr<_Tp>(__r, __p) : shared_ptr<_Tp>();
+}
+
+template<class _Tp, class _Up>
+shared_ptr<_Tp>
+const_pointer_cast(const shared_ptr<_Up>& __r) _NOEXCEPT
+{
+    typedef typename shared_ptr<_Tp>::element_type _RTp;
+    return shared_ptr<_Tp>(__r, const_cast<_RTp*>(__r.get()));
+}
+
+template<class _Tp, class _Up>
+shared_ptr<_Tp>
+reinterpret_pointer_cast(const shared_ptr<_Up>& __r) _NOEXCEPT
+{
+    return shared_ptr<_Tp>(__r,
+                           reinterpret_cast<
+                               typename shared_ptr<_Tp>::element_type*>(__r.get()));
+}
+
+#ifndef _LIBCPP_NO_RTTI
+
+template<class _Dp, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Dp*
+get_deleter(const shared_ptr<_Tp>& __p) _NOEXCEPT
+{
+    return __p.template __get_deleter<_Dp>();
+}
+
+#endif // _LIBCPP_NO_RTTI
+
+template<class _Tp>
+class _LIBCPP_SHARED_PTR_TRIVIAL_ABI _LIBCPP_TEMPLATE_VIS weak_ptr
+{
+public:
+    typedef _Tp element_type;
+private:
+    element_type*        __ptr_;
+    __shared_weak_count* __cntrl_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR weak_ptr() _NOEXCEPT;
+    template<class _Yp> _LIBCPP_INLINE_VISIBILITY weak_ptr(shared_ptr<_Yp> const& __r,
+                   typename enable_if<is_convertible<_Yp*, _Tp*>::value, __nat*>::type = 0)
+                        _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    weak_ptr(weak_ptr const& __r) _NOEXCEPT;
+    template<class _Yp> _LIBCPP_INLINE_VISIBILITY weak_ptr(weak_ptr<_Yp> const& __r,
+                   typename enable_if<is_convertible<_Yp*, _Tp*>::value, __nat*>::type = 0)
+                         _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    weak_ptr(weak_ptr&& __r) _NOEXCEPT;
+    template<class _Yp> _LIBCPP_INLINE_VISIBILITY weak_ptr(weak_ptr<_Yp>&& __r,
+                   typename enable_if<is_convertible<_Yp*, _Tp*>::value, __nat*>::type = 0)
+                         _NOEXCEPT;
+    ~weak_ptr();
+
+    _LIBCPP_INLINE_VISIBILITY
+    weak_ptr& operator=(weak_ptr const& __r) _NOEXCEPT;
+    template<class _Yp>
+        typename enable_if
+        <
+            is_convertible<_Yp*, element_type*>::value,
+            weak_ptr&
+        >::type
+        _LIBCPP_INLINE_VISIBILITY
+        operator=(weak_ptr<_Yp> const& __r) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    weak_ptr& operator=(weak_ptr&& __r) _NOEXCEPT;
+    template<class _Yp>
+        typename enable_if
+        <
+            is_convertible<_Yp*, element_type*>::value,
+            weak_ptr&
+        >::type
+        _LIBCPP_INLINE_VISIBILITY
+        operator=(weak_ptr<_Yp>&& __r) _NOEXCEPT;
+
+    template<class _Yp>
+        typename enable_if
+        <
+            is_convertible<_Yp*, element_type*>::value,
+            weak_ptr&
+        >::type
+        _LIBCPP_INLINE_VISIBILITY
+        operator=(shared_ptr<_Yp> const& __r) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(weak_ptr& __r) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    long use_count() const _NOEXCEPT
+        {return __cntrl_ ? __cntrl_->use_count() : 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    bool expired() const _NOEXCEPT
+        {return __cntrl_ == nullptr || __cntrl_->use_count() == 0;}
+    shared_ptr<_Tp> lock() const _NOEXCEPT;
+    template<class _Up>
+        _LIBCPP_INLINE_VISIBILITY
+        bool owner_before(const shared_ptr<_Up>& __r) const _NOEXCEPT
+        {return __cntrl_ < __r.__cntrl_;}
+    template<class _Up>
+        _LIBCPP_INLINE_VISIBILITY
+        bool owner_before(const weak_ptr<_Up>& __r) const _NOEXCEPT
+        {return __cntrl_ < __r.__cntrl_;}
+
+    template <class _Up> friend class _LIBCPP_TEMPLATE_VIS weak_ptr;
+    template <class _Up> friend class _LIBCPP_TEMPLATE_VIS shared_ptr;
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _Tp>
+weak_ptr(shared_ptr<_Tp>) -> weak_ptr<_Tp>;
+#endif
+
+template<class _Tp>
+inline
+_LIBCPP_CONSTEXPR
+weak_ptr<_Tp>::weak_ptr() _NOEXCEPT
+    : __ptr_(nullptr),
+      __cntrl_(nullptr)
+{
+}
+
+template<class _Tp>
+inline
+weak_ptr<_Tp>::weak_ptr(weak_ptr const& __r) _NOEXCEPT
+    : __ptr_(__r.__ptr_),
+      __cntrl_(__r.__cntrl_)
+{
+    if (__cntrl_)
+        __cntrl_->__add_weak();
+}
+
+template<class _Tp>
+template<class _Yp>
+inline
+weak_ptr<_Tp>::weak_ptr(shared_ptr<_Yp> const& __r,
+                        typename enable_if<is_convertible<_Yp*, _Tp*>::value, __nat*>::type)
+                         _NOEXCEPT
+    : __ptr_(__r.__ptr_),
+      __cntrl_(__r.__cntrl_)
+{
+    if (__cntrl_)
+        __cntrl_->__add_weak();
+}
+
+template<class _Tp>
+template<class _Yp>
+inline
+weak_ptr<_Tp>::weak_ptr(weak_ptr<_Yp> const& __r,
+                        typename enable_if<is_convertible<_Yp*, _Tp*>::value, __nat*>::type)
+         _NOEXCEPT
+    : __ptr_(__r.__ptr_),
+      __cntrl_(__r.__cntrl_)
+{
+    if (__cntrl_)
+        __cntrl_->__add_weak();
+}
+
+template<class _Tp>
+inline
+weak_ptr<_Tp>::weak_ptr(weak_ptr&& __r) _NOEXCEPT
+    : __ptr_(__r.__ptr_),
+      __cntrl_(__r.__cntrl_)
+{
+    __r.__ptr_ = nullptr;
+    __r.__cntrl_ = nullptr;
+}
+
+template<class _Tp>
+template<class _Yp>
+inline
+weak_ptr<_Tp>::weak_ptr(weak_ptr<_Yp>&& __r,
+                        typename enable_if<is_convertible<_Yp*, _Tp*>::value, __nat*>::type)
+         _NOEXCEPT
+    : __ptr_(__r.__ptr_),
+      __cntrl_(__r.__cntrl_)
+{
+    __r.__ptr_ = nullptr;
+    __r.__cntrl_ = nullptr;
+}
+
+template<class _Tp>
+weak_ptr<_Tp>::~weak_ptr()
+{
+    if (__cntrl_)
+        __cntrl_->__release_weak();
+}
+
+template<class _Tp>
+inline
+weak_ptr<_Tp>&
+weak_ptr<_Tp>::operator=(weak_ptr const& __r) _NOEXCEPT
+{
+    weak_ptr(__r).swap(*this);
+    return *this;
+}
+
+template<class _Tp>
+template<class _Yp>
+inline
+typename enable_if
+<
+    is_convertible<_Yp*, _Tp*>::value,
+    weak_ptr<_Tp>&
+>::type
+weak_ptr<_Tp>::operator=(weak_ptr<_Yp> const& __r) _NOEXCEPT
+{
+    weak_ptr(__r).swap(*this);
+    return *this;
+}
+
+template<class _Tp>
+inline
+weak_ptr<_Tp>&
+weak_ptr<_Tp>::operator=(weak_ptr&& __r) _NOEXCEPT
+{
+    weak_ptr(_VSTD::move(__r)).swap(*this);
+    return *this;
+}
+
+template<class _Tp>
+template<class _Yp>
+inline
+typename enable_if
+<
+    is_convertible<_Yp*, _Tp*>::value,
+    weak_ptr<_Tp>&
+>::type
+weak_ptr<_Tp>::operator=(weak_ptr<_Yp>&& __r) _NOEXCEPT
+{
+    weak_ptr(_VSTD::move(__r)).swap(*this);
+    return *this;
+}
+
+template<class _Tp>
+template<class _Yp>
+inline
+typename enable_if
+<
+    is_convertible<_Yp*, _Tp*>::value,
+    weak_ptr<_Tp>&
+>::type
+weak_ptr<_Tp>::operator=(shared_ptr<_Yp> const& __r) _NOEXCEPT
+{
+    weak_ptr(__r).swap(*this);
+    return *this;
+}
+
+template<class _Tp>
+inline
+void
+weak_ptr<_Tp>::swap(weak_ptr& __r) _NOEXCEPT
+{
+    _VSTD::swap(__ptr_, __r.__ptr_);
+    _VSTD::swap(__cntrl_, __r.__cntrl_);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(weak_ptr<_Tp>& __x, weak_ptr<_Tp>& __y) _NOEXCEPT
+{
+    __x.swap(__y);
+}
+
+template<class _Tp>
+inline
+void
+weak_ptr<_Tp>::reset() _NOEXCEPT
+{
+    weak_ptr().swap(*this);
+}
+
+template<class _Tp>
+template<class _Yp>
+shared_ptr<_Tp>::shared_ptr(const weak_ptr<_Yp>& __r,
+                            typename enable_if<is_convertible<_Yp*, element_type*>::value, __nat>::type)
+    : __ptr_(__r.__ptr_),
+      __cntrl_(__r.__cntrl_ ? __r.__cntrl_->lock() : __r.__cntrl_)
+{
+    if (__cntrl_ == nullptr)
+        __throw_bad_weak_ptr();
+}
+
+template<class _Tp>
+shared_ptr<_Tp>
+weak_ptr<_Tp>::lock() const _NOEXCEPT
+{
+    shared_ptr<_Tp> __r;
+    __r.__cntrl_ = __cntrl_ ? __cntrl_->lock() : __cntrl_;
+    if (__r.__cntrl_)
+        __r.__ptr_ = __ptr_;
+    return __r;
+}
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp = void> struct owner_less;
+#else
+template <class _Tp> struct owner_less;
+#endif
+
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS owner_less<shared_ptr<_Tp> >
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<shared_ptr<_Tp>, shared_ptr<_Tp>, bool>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef shared_ptr<_Tp> first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef shared_ptr<_Tp> second_argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(shared_ptr<_Tp> const& __x, shared_ptr<_Tp> const& __y) const _NOEXCEPT
+        {return __x.owner_before(__y);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(shared_ptr<_Tp> const& __x,   weak_ptr<_Tp> const& __y) const _NOEXCEPT
+        {return __x.owner_before(__y);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(  weak_ptr<_Tp> const& __x, shared_ptr<_Tp> const& __y) const _NOEXCEPT
+        {return __x.owner_before(__y);}
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS owner_less<weak_ptr<_Tp> >
+#if !defined(_LIBCPP_ABI_NO_BINDER_BASES)
+    : binary_function<weak_ptr<_Tp>, weak_ptr<_Tp>, bool>
+#endif
+{
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef bool result_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef weak_ptr<_Tp> first_argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef weak_ptr<_Tp> second_argument_type;
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(  weak_ptr<_Tp> const& __x,   weak_ptr<_Tp> const& __y) const _NOEXCEPT
+        {return __x.owner_before(__y);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(shared_ptr<_Tp> const& __x,   weak_ptr<_Tp> const& __y) const _NOEXCEPT
+        {return __x.owner_before(__y);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(  weak_ptr<_Tp> const& __x, shared_ptr<_Tp> const& __y) const _NOEXCEPT
+        {return __x.owner_before(__y);}
+};
+
+#if _LIBCPP_STD_VER > 14
+template <>
+struct _LIBCPP_TEMPLATE_VIS owner_less<void>
+{
+    template <class _Tp, class _Up>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()( shared_ptr<_Tp> const& __x, shared_ptr<_Up> const& __y) const _NOEXCEPT
+        {return __x.owner_before(__y);}
+    template <class _Tp, class _Up>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()( shared_ptr<_Tp> const& __x,   weak_ptr<_Up> const& __y) const _NOEXCEPT
+        {return __x.owner_before(__y);}
+    template <class _Tp, class _Up>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(   weak_ptr<_Tp> const& __x, shared_ptr<_Up> const& __y) const _NOEXCEPT
+        {return __x.owner_before(__y);}
+    template <class _Tp, class _Up>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(   weak_ptr<_Tp> const& __x,   weak_ptr<_Up> const& __y) const _NOEXCEPT
+        {return __x.owner_before(__y);}
+    typedef void is_transparent;
+};
+#endif
+
+template<class _Tp>
+class _LIBCPP_TEMPLATE_VIS enable_shared_from_this
+{
+    mutable weak_ptr<_Tp> __weak_this_;
+protected:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    enable_shared_from_this() _NOEXCEPT {}
+    _LIBCPP_INLINE_VISIBILITY
+    enable_shared_from_this(enable_shared_from_this const&) _NOEXCEPT {}
+    _LIBCPP_INLINE_VISIBILITY
+    enable_shared_from_this& operator=(enable_shared_from_this const&) _NOEXCEPT
+        {return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    ~enable_shared_from_this() {}
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    shared_ptr<_Tp> shared_from_this()
+        {return shared_ptr<_Tp>(__weak_this_);}
+    _LIBCPP_INLINE_VISIBILITY
+    shared_ptr<_Tp const> shared_from_this() const
+        {return shared_ptr<const _Tp>(__weak_this_);}
+
+#if _LIBCPP_STD_VER > 14
+    _LIBCPP_INLINE_VISIBILITY
+    weak_ptr<_Tp> weak_from_this() _NOEXCEPT
+       { return __weak_this_; }
+
+    _LIBCPP_INLINE_VISIBILITY
+    weak_ptr<const _Tp> weak_from_this() const _NOEXCEPT
+        { return __weak_this_; }
+#endif // _LIBCPP_STD_VER > 14
+
+    template <class _Up> friend class shared_ptr;
+};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS hash;
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS hash<shared_ptr<_Tp> >
+{
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef shared_ptr<_Tp> argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t          result_type;
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const shared_ptr<_Tp>& __ptr) const _NOEXCEPT
+    {
+        return hash<typename shared_ptr<_Tp>::element_type*>()(__ptr.get());
+    }
+};
+
+template<class _CharT, class _Traits, class _Yp>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, shared_ptr<_Yp> const& __p);
+
+
+#if !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
+
+class _LIBCPP_TYPE_VIS __sp_mut
+{
+    void* __lx;
+public:
+    void lock() _NOEXCEPT;
+    void unlock() _NOEXCEPT;
+
+private:
+    _LIBCPP_CONSTEXPR __sp_mut(void*) _NOEXCEPT;
+    __sp_mut(const __sp_mut&);
+    __sp_mut& operator=(const __sp_mut&);
+
+    friend _LIBCPP_FUNC_VIS __sp_mut& __get_sp_mut(const void*);
+};
+
+_LIBCPP_FUNC_VIS _LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
+__sp_mut& __get_sp_mut(const void*);
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_is_lock_free(const shared_ptr<_Tp>*)
+{
+    return false;
+}
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
+shared_ptr<_Tp>
+atomic_load(const shared_ptr<_Tp>* __p)
+{
+    __sp_mut& __m = __get_sp_mut(__p);
+    __m.lock();
+    shared_ptr<_Tp> __q = *__p;
+    __m.unlock();
+    return __q;
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
+shared_ptr<_Tp>
+atomic_load_explicit(const shared_ptr<_Tp>* __p, memory_order)
+{
+    return atomic_load(__p);
+}
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
+void
+atomic_store(shared_ptr<_Tp>* __p, shared_ptr<_Tp> __r)
+{
+    __sp_mut& __m = __get_sp_mut(__p);
+    __m.lock();
+    __p->swap(__r);
+    __m.unlock();
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
+void
+atomic_store_explicit(shared_ptr<_Tp>* __p, shared_ptr<_Tp> __r, memory_order)
+{
+    atomic_store(__p, __r);
+}
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
+shared_ptr<_Tp>
+atomic_exchange(shared_ptr<_Tp>* __p, shared_ptr<_Tp> __r)
+{
+    __sp_mut& __m = __get_sp_mut(__p);
+    __m.lock();
+    __p->swap(__r);
+    __m.unlock();
+    return __r;
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
+shared_ptr<_Tp>
+atomic_exchange_explicit(shared_ptr<_Tp>* __p, shared_ptr<_Tp> __r, memory_order)
+{
+    return atomic_exchange(__p, __r);
+}
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
+bool
+atomic_compare_exchange_strong(shared_ptr<_Tp>* __p, shared_ptr<_Tp>* __v, shared_ptr<_Tp> __w)
+{
+    shared_ptr<_Tp> __temp;
+    __sp_mut& __m = __get_sp_mut(__p);
+    __m.lock();
+    if (__p->__owner_equivalent(*__v))
+    {
+        _VSTD::swap(__temp, *__p);
+        *__p = __w;
+        __m.unlock();
+        return true;
+    }
+    _VSTD::swap(__temp, *__v);
+    *__v = *__p;
+    __m.unlock();
+    return false;
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
+bool
+atomic_compare_exchange_weak(shared_ptr<_Tp>* __p, shared_ptr<_Tp>* __v, shared_ptr<_Tp> __w)
+{
+    return atomic_compare_exchange_strong(__p, __v, __w);
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
+bool
+atomic_compare_exchange_strong_explicit(shared_ptr<_Tp>* __p, shared_ptr<_Tp>* __v,
+                                        shared_ptr<_Tp> __w, memory_order, memory_order)
+{
+    return atomic_compare_exchange_strong(__p, __v, __w);
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_ATOMIC_SHARED_PTR
+bool
+atomic_compare_exchange_weak_explicit(shared_ptr<_Tp>* __p, shared_ptr<_Tp>* __v,
+                                      shared_ptr<_Tp> __w, memory_order, memory_order)
+{
+    return atomic_compare_exchange_weak(__p, __v, __w);
+}
+
+#endif // !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_SHARED_PTR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/temporary_buffer.h b/contrib/libs/cxxsupp/libcxx/include/__memory/temporary_buffer.h
new file mode 100644
index 00000000000..06aa6c2936f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/temporary_buffer.h
@@ -0,0 +1,84 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_TEMPORARY_BUFFER_H
+#define _LIBCPP___MEMORY_TEMPORARY_BUFFER_H
+
+#include <__config>
+#include <cstddef>
+#include <new>
+#include <utility> // pair
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+_LIBCPP_NODISCARD_EXT _LIBCPP_NO_CFI
+pair<_Tp*, ptrdiff_t>
+get_temporary_buffer(ptrdiff_t __n) _NOEXCEPT
+{
+    pair<_Tp*, ptrdiff_t> __r(0, 0);
+    const ptrdiff_t __m = (~ptrdiff_t(0) ^
+                           ptrdiff_t(ptrdiff_t(1) << (sizeof(ptrdiff_t) * __CHAR_BIT__ - 1)))
+                           / sizeof(_Tp);
+    if (__n > __m)
+        __n = __m;
+    while (__n > 0)
+    {
+#if !defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION)
+    if (__is_overaligned_for_new(_LIBCPP_ALIGNOF(_Tp)))
+        {
+            align_val_t __al =
+                align_val_t(alignment_of<_Tp>::value);
+            __r.first = static_cast<_Tp*>(::operator new(
+                __n * sizeof(_Tp), __al, nothrow));
+        } else {
+            __r.first = static_cast<_Tp*>(::operator new(
+                __n * sizeof(_Tp), nothrow));
+        }
+#else
+    if (__is_overaligned_for_new(_LIBCPP_ALIGNOF(_Tp)))
+        {
+            // Since aligned operator new is unavailable, return an empty
+            // buffer rather than one with invalid alignment.
+            return __r;
+        }
+
+        __r.first = static_cast<_Tp*>(::operator new(__n * sizeof(_Tp), nothrow));
+#endif
+
+        if (__r.first)
+        {
+            __r.second = __n;
+            break;
+        }
+        __n /= 2;
+    }
+    return __r;
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+void return_temporary_buffer(_Tp* __p) _NOEXCEPT
+{
+  _VSTD::__libcpp_deallocate_unsized((void*)__p, _LIBCPP_ALIGNOF(_Tp));
+}
+
+struct __return_temporary_buffer
+{
+    template <class _Tp>
+    _LIBCPP_INLINE_VISIBILITY void operator()(_Tp* __p) const {_VSTD::return_temporary_buffer(__p);}
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_TEMPORARY_BUFFER_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/uninitialized_algorithms.h b/contrib/libs/cxxsupp/libcxx/include/__memory/uninitialized_algorithms.h
new file mode 100644
index 00000000000..e83d62e0db0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/uninitialized_algorithms.h
@@ -0,0 +1,241 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_UNINITIALIZED_ALGORITHMS_H
+#define _LIBCPP___MEMORY_UNINITIALIZED_ALGORITHMS_H
+
+#include <__config>
+#include <__memory/addressof.h>
+#include <__memory/construct_at.h>
+#include <iterator>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _ForwardIterator>
+_ForwardIterator
+uninitialized_copy(_InputIterator __f, _InputIterator __l, _ForwardIterator __r)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    _ForwardIterator __s = __r;
+    try
+    {
+#endif
+        for (; __f != __l; ++__f, (void) ++__r)
+            ::new ((void*)_VSTD::addressof(*__r)) value_type(*__f);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        for (; __s != __r; ++__s)
+            __s->~value_type();
+        throw;
+    }
+#endif
+    return __r;
+}
+
+template <class _InputIterator, class _Size, class _ForwardIterator>
+_ForwardIterator
+uninitialized_copy_n(_InputIterator __f, _Size __n, _ForwardIterator __r)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    _ForwardIterator __s = __r;
+    try
+    {
+#endif
+        for (; __n > 0; ++__f, (void) ++__r, (void) --__n)
+            ::new ((void*)_VSTD::addressof(*__r)) value_type(*__f);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        for (; __s != __r; ++__s)
+            __s->~value_type();
+        throw;
+    }
+#endif
+    return __r;
+}
+
+template <class _ForwardIterator, class _Tp>
+void
+uninitialized_fill(_ForwardIterator __f, _ForwardIterator __l, const _Tp& __x)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    _ForwardIterator __s = __f;
+    try
+    {
+#endif
+        for (; __f != __l; ++__f)
+            ::new ((void*)_VSTD::addressof(*__f)) value_type(__x);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        for (; __s != __f; ++__s)
+            __s->~value_type();
+        throw;
+    }
+#endif
+}
+
+template <class _ForwardIterator, class _Size, class _Tp>
+_ForwardIterator
+uninitialized_fill_n(_ForwardIterator __f, _Size __n, const _Tp& __x)
+{
+    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    _ForwardIterator __s = __f;
+    try
+    {
+#endif
+        for (; __n > 0; ++__f, (void) --__n)
+            ::new ((void*)_VSTD::addressof(*__f)) value_type(__x);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        for (; __s != __f; ++__s)
+            __s->~value_type();
+        throw;
+    }
+#endif
+    return __f;
+}
+
+#if _LIBCPP_STD_VER > 14
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void uninitialized_default_construct(_ForwardIterator __first, _ForwardIterator __last) {
+    using _Vt = typename iterator_traits<_ForwardIterator>::value_type;
+    auto __idx = __first;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try {
+#endif
+    for (; __idx != __last; ++__idx)
+        ::new ((void*)_VSTD::addressof(*__idx)) _Vt;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    } catch (...) {
+        _VSTD::destroy(__first, __idx);
+        throw;
+    }
+#endif
+}
+
+template <class _ForwardIterator, class _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator uninitialized_default_construct_n(_ForwardIterator __first, _Size __n) {
+    using _Vt = typename iterator_traits<_ForwardIterator>::value_type;
+    auto __idx = __first;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try {
+#endif
+    for (; __n > 0; ++__idx, (void) --__n)
+        ::new ((void*)_VSTD::addressof(*__idx)) _Vt;
+    return __idx;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    } catch (...) {
+        _VSTD::destroy(__first, __idx);
+        throw;
+    }
+#endif
+}
+
+
+template <class _ForwardIterator>
+inline _LIBCPP_INLINE_VISIBILITY
+void uninitialized_value_construct(_ForwardIterator __first, _ForwardIterator __last) {
+    using _Vt = typename iterator_traits<_ForwardIterator>::value_type;
+    auto __idx = __first;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try {
+#endif
+    for (; __idx != __last; ++__idx)
+        ::new ((void*)_VSTD::addressof(*__idx)) _Vt();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    } catch (...) {
+        _VSTD::destroy(__first, __idx);
+        throw;
+    }
+#endif
+}
+
+template <class _ForwardIterator, class _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIterator uninitialized_value_construct_n(_ForwardIterator __first, _Size __n) {
+    using _Vt = typename iterator_traits<_ForwardIterator>::value_type;
+    auto __idx = __first;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try {
+#endif
+    for (; __n > 0; ++__idx, (void) --__n)
+        ::new ((void*)_VSTD::addressof(*__idx)) _Vt();
+    return __idx;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    } catch (...) {
+        _VSTD::destroy(__first, __idx);
+        throw;
+    }
+#endif
+}
+
+
+template <class _InputIt, class _ForwardIt>
+inline _LIBCPP_INLINE_VISIBILITY
+_ForwardIt uninitialized_move(_InputIt __first, _InputIt __last, _ForwardIt __first_res) {
+    using _Vt = typename iterator_traits<_ForwardIt>::value_type;
+    auto __idx = __first_res;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try {
+#endif
+    for (; __first != __last; ++__idx, (void) ++__first)
+        ::new ((void*)_VSTD::addressof(*__idx)) _Vt(_VSTD::move(*__first));
+    return __idx;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    } catch (...) {
+        _VSTD::destroy(__first_res, __idx);
+        throw;
+    }
+#endif
+}
+
+template <class _InputIt, class _Size, class _ForwardIt>
+inline _LIBCPP_INLINE_VISIBILITY
+pair<_InputIt, _ForwardIt>
+uninitialized_move_n(_InputIt __first, _Size __n, _ForwardIt __first_res) {
+    using _Vt = typename iterator_traits<_ForwardIt>::value_type;
+    auto __idx = __first_res;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try {
+#endif
+    for (; __n > 0; ++__idx, (void) ++__first, --__n)
+        ::new ((void*)_VSTD::addressof(*__idx)) _Vt(_VSTD::move(*__first));
+    return {__first, __idx};
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    } catch (...) {
+        _VSTD::destroy(__first_res, __idx);
+        throw;
+    }
+#endif
+}
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_UNINITIALIZED_ALGORITHMS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/unique_ptr.h b/contrib/libs/cxxsupp/libcxx/include/__memory/unique_ptr.h
new file mode 100644
index 00000000000..7a0e4645fa8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/unique_ptr.h
@@ -0,0 +1,769 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_UNIQUE_PTR_H
+#define _LIBCPP___MEMORY_UNIQUE_PTR_H
+
+#include <__config>
+#include <__functional_base>
+#include <__functional/hash.h>
+#include <__functional/operations.h>
+#include <__memory/allocator_traits.h> // __pointer
+#include <__memory/compressed_pair.h>
+#include <__utility/forward.h>
+#include <cstddef>
+#include <stlfwd>
+#include <type_traits>
+#include <utility>
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR)
+#   include <__memory/auto_ptr.h>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS default_delete {
+    static_assert(!is_function<_Tp>::value,
+                  "default_delete cannot be instantiated for function types");
+#ifndef _LIBCPP_CXX03_LANG
+  _LIBCPP_INLINE_VISIBILITY constexpr default_delete() _NOEXCEPT = default;
+#else
+  _LIBCPP_INLINE_VISIBILITY default_delete() {}
+#endif
+  template <class _Up>
+  _LIBCPP_INLINE_VISIBILITY
+  default_delete(const default_delete<_Up>&,
+                 typename enable_if<is_convertible<_Up*, _Tp*>::value>::type* =
+                     0) _NOEXCEPT {}
+
+  _LIBCPP_INLINE_VISIBILITY void operator()(_Tp* __ptr) const _NOEXCEPT {
+    static_assert(sizeof(_Tp) > 0,
+                  "default_delete can not delete incomplete type");
+    static_assert(!is_void<_Tp>::value,
+                  "default_delete can not delete incomplete type");
+    delete __ptr;
+  }
+};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS default_delete<_Tp[]> {
+private:
+  template <class _Up>
+  struct _EnableIfConvertible
+      : enable_if<is_convertible<_Up(*)[], _Tp(*)[]>::value> {};
+
+public:
+#ifndef _LIBCPP_CXX03_LANG
+  _LIBCPP_INLINE_VISIBILITY constexpr default_delete() _NOEXCEPT = default;
+#else
+  _LIBCPP_INLINE_VISIBILITY default_delete() {}
+#endif
+
+  template <class _Up>
+  _LIBCPP_INLINE_VISIBILITY
+  default_delete(const default_delete<_Up[]>&,
+                 typename _EnableIfConvertible<_Up>::type* = 0) _NOEXCEPT {}
+
+  template <class _Up>
+  _LIBCPP_INLINE_VISIBILITY
+  typename _EnableIfConvertible<_Up>::type
+  operator()(_Up* __ptr) const _NOEXCEPT {
+    static_assert(sizeof(_Tp) > 0,
+                  "default_delete can not delete incomplete type");
+    static_assert(!is_void<_Tp>::value,
+                  "default_delete can not delete void type");
+    delete[] __ptr;
+  }
+};
+
+template <class _Deleter>
+struct __unique_ptr_deleter_sfinae {
+  static_assert(!is_reference<_Deleter>::value, "incorrect specialization");
+  typedef const _Deleter& __lval_ref_type;
+  typedef _Deleter&& __good_rval_ref_type;
+  typedef true_type __enable_rval_overload;
+};
+
+template <class _Deleter>
+struct __unique_ptr_deleter_sfinae<_Deleter const&> {
+  typedef const _Deleter& __lval_ref_type;
+  typedef const _Deleter&& __bad_rval_ref_type;
+  typedef false_type __enable_rval_overload;
+};
+
+template <class _Deleter>
+struct __unique_ptr_deleter_sfinae<_Deleter&> {
+  typedef _Deleter& __lval_ref_type;
+  typedef _Deleter&& __bad_rval_ref_type;
+  typedef false_type __enable_rval_overload;
+};
+
+#if defined(_LIBCPP_ABI_ENABLE_UNIQUE_PTR_TRIVIAL_ABI)
+#  define _LIBCPP_UNIQUE_PTR_TRIVIAL_ABI __attribute__((trivial_abi))
+#else
+#  define _LIBCPP_UNIQUE_PTR_TRIVIAL_ABI
+#endif
+
+template <class _Tp, class _Dp>
+class _LIBCPP_UNIQUE_PTR_TRIVIAL_ABI _LIBCPP_TEMPLATE_VIS unique_ptr {
+public:
+  typedef _Tp element_type;
+  typedef _Dp deleter_type;
+  typedef _LIBCPP_NODEBUG typename __pointer<_Tp, deleter_type>::type pointer;
+
+  static_assert(!is_rvalue_reference<deleter_type>::value,
+                "the specified deleter type cannot be an rvalue reference");
+
+private:
+  __compressed_pair<pointer, deleter_type> __ptr_;
+
+  struct __nat { int __for_bool_; };
+
+  typedef _LIBCPP_NODEBUG __unique_ptr_deleter_sfinae<_Dp> _DeleterSFINAE;
+
+  template <bool _Dummy>
+  using _LValRefType _LIBCPP_NODEBUG =
+      typename __dependent_type<_DeleterSFINAE, _Dummy>::__lval_ref_type;
+
+  template <bool _Dummy>
+  using _GoodRValRefType _LIBCPP_NODEBUG =
+      typename __dependent_type<_DeleterSFINAE, _Dummy>::__good_rval_ref_type;
+
+  template <bool _Dummy>
+  using _BadRValRefType _LIBCPP_NODEBUG =
+      typename __dependent_type<_DeleterSFINAE, _Dummy>::__bad_rval_ref_type;
+
+  template <bool _Dummy, class _Deleter = typename __dependent_type<
+                             __identity<deleter_type>, _Dummy>::type>
+  using _EnableIfDeleterDefaultConstructible _LIBCPP_NODEBUG =
+      typename enable_if<is_default_constructible<_Deleter>::value &&
+                         !is_pointer<_Deleter>::value>::type;
+
+  template <class _ArgType>
+  using _EnableIfDeleterConstructible _LIBCPP_NODEBUG =
+      typename enable_if<is_constructible<deleter_type, _ArgType>::value>::type;
+
+  template <class _UPtr, class _Up>
+  using _EnableIfMoveConvertible _LIBCPP_NODEBUG = typename enable_if<
+      is_convertible<typename _UPtr::pointer, pointer>::value &&
+      !is_array<_Up>::value
+  >::type;
+
+  template <class _UDel>
+  using _EnableIfDeleterConvertible _LIBCPP_NODEBUG = typename enable_if<
+      (is_reference<_Dp>::value && is_same<_Dp, _UDel>::value) ||
+      (!is_reference<_Dp>::value && is_convertible<_UDel, _Dp>::value)
+    >::type;
+
+  template <class _UDel>
+  using _EnableIfDeleterAssignable = typename enable_if<
+      is_assignable<_Dp&, _UDel&&>::value
+    >::type;
+
+public:
+  template <bool _Dummy = true,
+            class = _EnableIfDeleterDefaultConstructible<_Dummy> >
+  _LIBCPP_INLINE_VISIBILITY
+  _LIBCPP_CONSTEXPR unique_ptr() _NOEXCEPT : __ptr_(pointer(), __default_init_tag()) {}
+
+  template <bool _Dummy = true,
+            class = _EnableIfDeleterDefaultConstructible<_Dummy> >
+  _LIBCPP_INLINE_VISIBILITY
+  _LIBCPP_CONSTEXPR unique_ptr(nullptr_t) _NOEXCEPT : __ptr_(pointer(), __default_init_tag()) {}
+
+  template <bool _Dummy = true,
+            class = _EnableIfDeleterDefaultConstructible<_Dummy> >
+  _LIBCPP_INLINE_VISIBILITY
+  explicit unique_ptr(pointer __p) _NOEXCEPT : __ptr_(__p, __default_init_tag()) {}
+
+  template <bool _Dummy = true,
+            class = _EnableIfDeleterConstructible<_LValRefType<_Dummy> > >
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr(pointer __p, _LValRefType<_Dummy> __d) _NOEXCEPT
+      : __ptr_(__p, __d) {}
+
+  template <bool _Dummy = true,
+            class = _EnableIfDeleterConstructible<_GoodRValRefType<_Dummy> > >
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr(pointer __p, _GoodRValRefType<_Dummy> __d) _NOEXCEPT
+      : __ptr_(__p, _VSTD::move(__d)) {
+    static_assert(!is_reference<deleter_type>::value,
+                  "rvalue deleter bound to reference");
+  }
+
+  template <bool _Dummy = true,
+            class = _EnableIfDeleterConstructible<_BadRValRefType<_Dummy> > >
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr(pointer __p, _BadRValRefType<_Dummy> __d) = delete;
+
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr(unique_ptr&& __u) _NOEXCEPT
+      : __ptr_(__u.release(), _VSTD::forward<deleter_type>(__u.get_deleter())) {
+  }
+
+  template <class _Up, class _Ep,
+      class = _EnableIfMoveConvertible<unique_ptr<_Up, _Ep>, _Up>,
+      class = _EnableIfDeleterConvertible<_Ep>
+  >
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr(unique_ptr<_Up, _Ep>&& __u) _NOEXCEPT
+      : __ptr_(__u.release(), _VSTD::forward<_Ep>(__u.get_deleter())) {}
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR)
+  template <class _Up>
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr(auto_ptr<_Up>&& __p,
+             typename enable_if<is_convertible<_Up*, _Tp*>::value &&
+                                    is_same<_Dp, default_delete<_Tp> >::value,
+                                __nat>::type = __nat()) _NOEXCEPT
+      : __ptr_(__p.release(), __default_init_tag()) {}
+#endif
+
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr& operator=(unique_ptr&& __u) _NOEXCEPT {
+    reset(__u.release());
+    __ptr_.second() = _VSTD::forward<deleter_type>(__u.get_deleter());
+    return *this;
+  }
+
+  template <class _Up, class _Ep,
+      class = _EnableIfMoveConvertible<unique_ptr<_Up, _Ep>, _Up>,
+      class = _EnableIfDeleterAssignable<_Ep>
+  >
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr& operator=(unique_ptr<_Up, _Ep>&& __u) _NOEXCEPT {
+    reset(__u.release());
+    __ptr_.second() = _VSTD::forward<_Ep>(__u.get_deleter());
+    return *this;
+  }
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR)
+  template <class _Up>
+  _LIBCPP_INLINE_VISIBILITY
+      typename enable_if<is_convertible<_Up*, _Tp*>::value &&
+                             is_same<_Dp, default_delete<_Tp> >::value,
+                         unique_ptr&>::type
+      operator=(auto_ptr<_Up> __p) {
+    reset(__p.release());
+    return *this;
+  }
+#endif
+
+#ifdef _LIBCPP_CXX03_LANG
+  unique_ptr(unique_ptr const&) = delete;
+  unique_ptr& operator=(unique_ptr const&) = delete;
+#endif
+
+
+  _LIBCPP_INLINE_VISIBILITY
+  ~unique_ptr() { reset(); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr& operator=(nullptr_t) _NOEXCEPT {
+    reset();
+    return *this;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  typename add_lvalue_reference<_Tp>::type
+  operator*() const {
+    return *__ptr_.first();
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  pointer operator->() const _NOEXCEPT {
+    return __ptr_.first();
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  pointer get() const _NOEXCEPT {
+    return __ptr_.first();
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  deleter_type& get_deleter() _NOEXCEPT {
+    return __ptr_.second();
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  const deleter_type& get_deleter() const _NOEXCEPT {
+    return __ptr_.second();
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  explicit operator bool() const _NOEXCEPT {
+    return __ptr_.first() != nullptr;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  pointer release() _NOEXCEPT {
+    pointer __t = __ptr_.first();
+    __ptr_.first() = pointer();
+    return __t;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void reset(pointer __p = pointer()) _NOEXCEPT {
+    pointer __tmp = __ptr_.first();
+    __ptr_.first() = __p;
+    if (__tmp)
+      __ptr_.second()(__tmp);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void swap(unique_ptr& __u) _NOEXCEPT {
+    __ptr_.swap(__u.__ptr_);
+  }
+};
+
+
+template <class _Tp, class _Dp>
+class _LIBCPP_UNIQUE_PTR_TRIVIAL_ABI _LIBCPP_TEMPLATE_VIS unique_ptr<_Tp[], _Dp> {
+public:
+  typedef _Tp element_type;
+  typedef _Dp deleter_type;
+  typedef typename __pointer<_Tp, deleter_type>::type pointer;
+
+private:
+  __compressed_pair<pointer, deleter_type> __ptr_;
+
+  template <class _From>
+  struct _CheckArrayPointerConversion : is_same<_From, pointer> {};
+
+  template <class _FromElem>
+  struct _CheckArrayPointerConversion<_FromElem*>
+      : integral_constant<bool,
+          is_same<_FromElem*, pointer>::value ||
+            (is_same<pointer, element_type*>::value &&
+             is_convertible<_FromElem(*)[], element_type(*)[]>::value)
+      >
+  {};
+
+  typedef __unique_ptr_deleter_sfinae<_Dp> _DeleterSFINAE;
+
+  template <bool _Dummy>
+  using _LValRefType _LIBCPP_NODEBUG =
+      typename __dependent_type<_DeleterSFINAE, _Dummy>::__lval_ref_type;
+
+  template <bool _Dummy>
+  using _GoodRValRefType _LIBCPP_NODEBUG =
+      typename __dependent_type<_DeleterSFINAE, _Dummy>::__good_rval_ref_type;
+
+  template <bool _Dummy>
+  using _BadRValRefType _LIBCPP_NODEBUG =
+      typename __dependent_type<_DeleterSFINAE, _Dummy>::__bad_rval_ref_type;
+
+  template <bool _Dummy, class _Deleter = typename __dependent_type<
+                             __identity<deleter_type>, _Dummy>::type>
+  using _EnableIfDeleterDefaultConstructible _LIBCPP_NODEBUG =
+      typename enable_if<is_default_constructible<_Deleter>::value &&
+                         !is_pointer<_Deleter>::value>::type;
+
+  template <class _ArgType>
+  using _EnableIfDeleterConstructible _LIBCPP_NODEBUG =
+      typename enable_if<is_constructible<deleter_type, _ArgType>::value>::type;
+
+  template <class _Pp>
+  using _EnableIfPointerConvertible _LIBCPP_NODEBUG = typename enable_if<
+      _CheckArrayPointerConversion<_Pp>::value
+  >::type;
+
+  template <class _UPtr, class _Up,
+        class _ElemT = typename _UPtr::element_type>
+  using _EnableIfMoveConvertible _LIBCPP_NODEBUG = typename enable_if<
+      is_array<_Up>::value &&
+      is_same<pointer, element_type*>::value &&
+      is_same<typename _UPtr::pointer, _ElemT*>::value &&
+      is_convertible<_ElemT(*)[], element_type(*)[]>::value
+    >::type;
+
+  template <class _UDel>
+  using _EnableIfDeleterConvertible _LIBCPP_NODEBUG = typename enable_if<
+      (is_reference<_Dp>::value && is_same<_Dp, _UDel>::value) ||
+      (!is_reference<_Dp>::value && is_convertible<_UDel, _Dp>::value)
+    >::type;
+
+  template <class _UDel>
+  using _EnableIfDeleterAssignable _LIBCPP_NODEBUG = typename enable_if<
+      is_assignable<_Dp&, _UDel&&>::value
+    >::type;
+
+public:
+  template <bool _Dummy = true,
+            class = _EnableIfDeleterDefaultConstructible<_Dummy> >
+  _LIBCPP_INLINE_VISIBILITY
+  _LIBCPP_CONSTEXPR unique_ptr() _NOEXCEPT : __ptr_(pointer(), __default_init_tag()) {}
+
+  template <bool _Dummy = true,
+            class = _EnableIfDeleterDefaultConstructible<_Dummy> >
+  _LIBCPP_INLINE_VISIBILITY
+  _LIBCPP_CONSTEXPR unique_ptr(nullptr_t) _NOEXCEPT : __ptr_(pointer(), __default_init_tag()) {}
+
+  template <class _Pp, bool _Dummy = true,
+            class = _EnableIfDeleterDefaultConstructible<_Dummy>,
+            class = _EnableIfPointerConvertible<_Pp> >
+  _LIBCPP_INLINE_VISIBILITY
+  explicit unique_ptr(_Pp __p) _NOEXCEPT
+      : __ptr_(__p, __default_init_tag()) {}
+
+  template <class _Pp, bool _Dummy = true,
+            class = _EnableIfDeleterConstructible<_LValRefType<_Dummy> >,
+            class = _EnableIfPointerConvertible<_Pp> >
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr(_Pp __p, _LValRefType<_Dummy> __d) _NOEXCEPT
+      : __ptr_(__p, __d) {}
+
+  template <bool _Dummy = true,
+            class = _EnableIfDeleterConstructible<_LValRefType<_Dummy> > >
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr(nullptr_t, _LValRefType<_Dummy> __d) _NOEXCEPT
+      : __ptr_(nullptr, __d) {}
+
+  template <class _Pp, bool _Dummy = true,
+            class = _EnableIfDeleterConstructible<_GoodRValRefType<_Dummy> >,
+            class = _EnableIfPointerConvertible<_Pp> >
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr(_Pp __p, _GoodRValRefType<_Dummy> __d) _NOEXCEPT
+      : __ptr_(__p, _VSTD::move(__d)) {
+    static_assert(!is_reference<deleter_type>::value,
+                  "rvalue deleter bound to reference");
+  }
+
+  template <bool _Dummy = true,
+            class = _EnableIfDeleterConstructible<_GoodRValRefType<_Dummy> > >
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr(nullptr_t, _GoodRValRefType<_Dummy> __d) _NOEXCEPT
+      : __ptr_(nullptr, _VSTD::move(__d)) {
+    static_assert(!is_reference<deleter_type>::value,
+                  "rvalue deleter bound to reference");
+  }
+
+  template <class _Pp, bool _Dummy = true,
+            class = _EnableIfDeleterConstructible<_BadRValRefType<_Dummy> >,
+            class = _EnableIfPointerConvertible<_Pp> >
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr(_Pp __p, _BadRValRefType<_Dummy> __d) = delete;
+
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr(unique_ptr&& __u) _NOEXCEPT
+      : __ptr_(__u.release(), _VSTD::forward<deleter_type>(__u.get_deleter())) {
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr& operator=(unique_ptr&& __u) _NOEXCEPT {
+    reset(__u.release());
+    __ptr_.second() = _VSTD::forward<deleter_type>(__u.get_deleter());
+    return *this;
+  }
+
+  template <class _Up, class _Ep,
+      class = _EnableIfMoveConvertible<unique_ptr<_Up, _Ep>, _Up>,
+      class = _EnableIfDeleterConvertible<_Ep>
+  >
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr(unique_ptr<_Up, _Ep>&& __u) _NOEXCEPT
+      : __ptr_(__u.release(), _VSTD::forward<_Ep>(__u.get_deleter())) {
+  }
+
+  template <class _Up, class _Ep,
+      class = _EnableIfMoveConvertible<unique_ptr<_Up, _Ep>, _Up>,
+      class = _EnableIfDeleterAssignable<_Ep>
+  >
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr&
+  operator=(unique_ptr<_Up, _Ep>&& __u) _NOEXCEPT {
+    reset(__u.release());
+    __ptr_.second() = _VSTD::forward<_Ep>(__u.get_deleter());
+    return *this;
+  }
+
+#ifdef _LIBCPP_CXX03_LANG
+  unique_ptr(unique_ptr const&) = delete;
+  unique_ptr& operator=(unique_ptr const&) = delete;
+#endif
+
+public:
+  _LIBCPP_INLINE_VISIBILITY
+  ~unique_ptr() { reset(); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  unique_ptr& operator=(nullptr_t) _NOEXCEPT {
+    reset();
+    return *this;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  typename add_lvalue_reference<_Tp>::type
+  operator[](size_t __i) const {
+    return __ptr_.first()[__i];
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  pointer get() const _NOEXCEPT {
+    return __ptr_.first();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  deleter_type& get_deleter() _NOEXCEPT {
+    return __ptr_.second();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  const deleter_type& get_deleter() const _NOEXCEPT {
+    return __ptr_.second();
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  explicit operator bool() const _NOEXCEPT {
+    return __ptr_.first() != nullptr;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  pointer release() _NOEXCEPT {
+    pointer __t = __ptr_.first();
+    __ptr_.first() = pointer();
+    return __t;
+  }
+
+  template <class _Pp>
+  _LIBCPP_INLINE_VISIBILITY
+  typename enable_if<
+      _CheckArrayPointerConversion<_Pp>::value
+  >::type
+  reset(_Pp __p) _NOEXCEPT {
+    pointer __tmp = __ptr_.first();
+    __ptr_.first() = __p;
+    if (__tmp)
+      __ptr_.second()(__tmp);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void reset(nullptr_t = nullptr) _NOEXCEPT {
+    pointer __tmp = __ptr_.first();
+    __ptr_.first() = nullptr;
+    if (__tmp)
+      __ptr_.second()(__tmp);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void swap(unique_ptr& __u) _NOEXCEPT {
+    __ptr_.swap(__u.__ptr_);
+  }
+
+};
+
+template <class _Tp, class _Dp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if<
+    __is_swappable<_Dp>::value,
+    void
+>::type
+swap(unique_ptr<_Tp, _Dp>& __x, unique_ptr<_Tp, _Dp>& __y) _NOEXCEPT {__x.swap(__y);}
+
+template <class _T1, class _D1, class _T2, class _D2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const unique_ptr<_T1, _D1>& __x, const unique_ptr<_T2, _D2>& __y) {return __x.get() == __y.get();}
+
+template <class _T1, class _D1, class _T2, class _D2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const unique_ptr<_T1, _D1>& __x, const unique_ptr<_T2, _D2>& __y) {return !(__x == __y);}
+
+template <class _T1, class _D1, class _T2, class _D2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const unique_ptr<_T1, _D1>& __x, const unique_ptr<_T2, _D2>& __y)
+{
+    typedef typename unique_ptr<_T1, _D1>::pointer _P1;
+    typedef typename unique_ptr<_T2, _D2>::pointer _P2;
+    typedef typename common_type<_P1, _P2>::type _Vp;
+    return less<_Vp>()(__x.get(), __y.get());
+}
+
+template <class _T1, class _D1, class _T2, class _D2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const unique_ptr<_T1, _D1>& __x, const unique_ptr<_T2, _D2>& __y) {return __y < __x;}
+
+template <class _T1, class _D1, class _T2, class _D2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const unique_ptr<_T1, _D1>& __x, const unique_ptr<_T2, _D2>& __y) {return !(__y < __x);}
+
+template <class _T1, class _D1, class _T2, class _D2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const unique_ptr<_T1, _D1>& __x, const unique_ptr<_T2, _D2>& __y) {return !(__x < __y);}
+
+template <class _T1, class _D1>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const unique_ptr<_T1, _D1>& __x, nullptr_t) _NOEXCEPT
+{
+    return !__x;
+}
+
+template <class _T1, class _D1>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(nullptr_t, const unique_ptr<_T1, _D1>& __x) _NOEXCEPT
+{
+    return !__x;
+}
+
+template <class _T1, class _D1>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const unique_ptr<_T1, _D1>& __x, nullptr_t) _NOEXCEPT
+{
+    return static_cast<bool>(__x);
+}
+
+template <class _T1, class _D1>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(nullptr_t, const unique_ptr<_T1, _D1>& __x) _NOEXCEPT
+{
+    return static_cast<bool>(__x);
+}
+
+template <class _T1, class _D1>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(const unique_ptr<_T1, _D1>& __x, nullptr_t)
+{
+    typedef typename unique_ptr<_T1, _D1>::pointer _P1;
+    return less<_P1>()(__x.get(), nullptr);
+}
+
+template <class _T1, class _D1>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(nullptr_t, const unique_ptr<_T1, _D1>& __x)
+{
+    typedef typename unique_ptr<_T1, _D1>::pointer _P1;
+    return less<_P1>()(nullptr, __x.get());
+}
+
+template <class _T1, class _D1>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>(const unique_ptr<_T1, _D1>& __x, nullptr_t)
+{
+    return nullptr < __x;
+}
+
+template <class _T1, class _D1>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>(nullptr_t, const unique_ptr<_T1, _D1>& __x)
+{
+    return __x < nullptr;
+}
+
+template <class _T1, class _D1>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const unique_ptr<_T1, _D1>& __x, nullptr_t)
+{
+    return !(nullptr < __x);
+}
+
+template <class _T1, class _D1>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(nullptr_t, const unique_ptr<_T1, _D1>& __x)
+{
+    return !(__x < nullptr);
+}
+
+template <class _T1, class _D1>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const unique_ptr<_T1, _D1>& __x, nullptr_t)
+{
+    return !(__x < nullptr);
+}
+
+template <class _T1, class _D1>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(nullptr_t, const unique_ptr<_T1, _D1>& __x)
+{
+    return !(nullptr < __x);
+}
+
+#if _LIBCPP_STD_VER > 11
+
+template<class _Tp>
+struct __unique_if
+{
+    typedef unique_ptr<_Tp> __unique_single;
+};
+
+template<class _Tp>
+struct __unique_if<_Tp[]>
+{
+    typedef unique_ptr<_Tp[]> __unique_array_unknown_bound;
+};
+
+template<class _Tp, size_t _Np>
+struct __unique_if<_Tp[_Np]>
+{
+    typedef void __unique_array_known_bound;
+};
+
+template<class _Tp, class... _Args>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __unique_if<_Tp>::__unique_single
+make_unique(_Args&&... __args)
+{
+    return unique_ptr<_Tp>(new _Tp(_VSTD::forward<_Args>(__args)...));
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __unique_if<_Tp>::__unique_array_unknown_bound
+make_unique(size_t __n)
+{
+    typedef typename remove_extent<_Tp>::type _Up;
+    return unique_ptr<_Tp>(new _Up[__n]());
+}
+
+template<class _Tp, class... _Args>
+    typename __unique_if<_Tp>::__unique_array_known_bound
+    make_unique(_Args&&...) = delete;
+
+#endif // _LIBCPP_STD_VER > 11
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS hash;
+
+template <class _Tp, class _Dp>
+#ifdef _LIBCPP_CXX03_LANG
+struct _LIBCPP_TEMPLATE_VIS hash<unique_ptr<_Tp, _Dp> >
+#else
+struct _LIBCPP_TEMPLATE_VIS hash<__enable_hash_helper<
+    unique_ptr<_Tp, _Dp>, typename unique_ptr<_Tp, _Dp>::pointer> >
+#endif
+{
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef unique_ptr<_Tp, _Dp> argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t               result_type;
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const unique_ptr<_Tp, _Dp>& __ptr) const
+    {
+        typedef typename unique_ptr<_Tp, _Dp>::pointer pointer;
+        return hash<pointer>()(__ptr.get());
+    }
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_UNIQUE_PTR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__memory/uses_allocator.h b/contrib/libs/cxxsupp/libcxx/include/__memory/uses_allocator.h
new file mode 100644
index 00000000000..5e29b7f1df3
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__memory/uses_allocator.h
@@ -0,0 +1,61 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MEMORY_USES_ALLOCATOR_H
+#define _LIBCPP___MEMORY_USES_ALLOCATOR_H
+
+#include <__config>
+#include <cstddef>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+struct __has_allocator_type
+{
+private:
+    struct __two {char __lx; char __lxx;};
+    template <class _Up> static __two __test(...);
+    // Fix for MSVC which allows to reference private types. Wrap into declval to prevent that.
+    template <class _Up> static char __test(decltype(_VSTD::declval<typename _Up::allocator_type*>()) = 0);
+public:
+    static const bool value = sizeof(__test<_Tp>(0)) == 1;
+};
+
+template <class _Tp, class _Alloc, bool = __has_allocator_type<_Tp>::value>
+struct __uses_allocator
+    : public integral_constant<bool,
+        is_convertible<_Alloc, typename _Tp::allocator_type>::value>
+{
+};
+
+template <class _Tp, class _Alloc>
+struct __uses_allocator<_Tp, _Alloc, false>
+    : public false_type
+{
+};
+
+template <class _Tp, class _Alloc>
+struct _LIBCPP_TEMPLATE_VIS uses_allocator
+    : public __uses_allocator<_Tp, _Alloc>
+{
+};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, class _Alloc>
+inline constexpr size_t uses_allocator_v = uses_allocator<_Tp, _Alloc>::value;
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___MEMORY_USES_ALLOCATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__mutex_base b/contrib/libs/cxxsupp/libcxx/include/__mutex_base
new file mode 100644
index 00000000000..da2967164a6
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__mutex_base
@@ -0,0 +1,527 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___MUTEX_BASE
+#define _LIBCPP___MUTEX_BASE
+
+#include <__config>
+#include <__threading_support>
+#include <chrono>
+#include <system_error>
+#include <time.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+
+class _LIBCPP_TYPE_VIS _LIBCPP_THREAD_SAFETY_ANNOTATION(capability("mutex")) mutex
+{
+    __libcpp_mutex_t __m_ = _LIBCPP_MUTEX_INITIALIZER;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR mutex() = default;
+
+    mutex(const mutex&) = delete;
+    mutex& operator=(const mutex&) = delete;
+
+#if defined(_LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION)
+    ~mutex() = default;
+#else
+    ~mutex() _NOEXCEPT;
+#endif
+
+    void lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability());
+    bool try_lock() _NOEXCEPT _LIBCPP_THREAD_SAFETY_ANNOTATION(try_acquire_capability(true));
+    void unlock() _NOEXCEPT _LIBCPP_THREAD_SAFETY_ANNOTATION(release_capability());
+
+    typedef __libcpp_mutex_t* native_handle_type;
+    _LIBCPP_INLINE_VISIBILITY native_handle_type native_handle() {return &__m_;}
+};
+
+static_assert(is_nothrow_default_constructible<mutex>::value,
+              "the default constructor for std::mutex must be nothrow");
+
+struct _LIBCPP_TYPE_VIS defer_lock_t { explicit defer_lock_t() = default; };
+struct _LIBCPP_TYPE_VIS try_to_lock_t { explicit try_to_lock_t() = default; };
+struct _LIBCPP_TYPE_VIS adopt_lock_t { explicit adopt_lock_t() = default; };
+
+#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
+
+extern _LIBCPP_EXPORTED_FROM_ABI const defer_lock_t  defer_lock;
+extern _LIBCPP_EXPORTED_FROM_ABI const try_to_lock_t try_to_lock;
+extern _LIBCPP_EXPORTED_FROM_ABI const adopt_lock_t  adopt_lock;
+
+#else
+
+/* inline */ constexpr defer_lock_t  defer_lock  = defer_lock_t();
+/* inline */ constexpr try_to_lock_t try_to_lock = try_to_lock_t();
+/* inline */ constexpr adopt_lock_t  adopt_lock  = adopt_lock_t();
+
+#endif
+
+template <class _Mutex>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_THREAD_SAFETY_ANNOTATION(scoped_lockable)
+lock_guard
+{
+public:
+    typedef _Mutex mutex_type;
+
+private:
+    mutex_type& __m_;
+public:
+
+    _LIBCPP_NODISCARD_EXT _LIBCPP_INLINE_VISIBILITY
+    explicit lock_guard(mutex_type& __m) _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability(__m))
+        : __m_(__m) {__m_.lock();}
+
+    _LIBCPP_NODISCARD_EXT _LIBCPP_INLINE_VISIBILITY
+    lock_guard(mutex_type& __m, adopt_lock_t) _LIBCPP_THREAD_SAFETY_ANNOTATION(requires_capability(__m))
+        : __m_(__m) {}
+    _LIBCPP_INLINE_VISIBILITY
+    ~lock_guard() _LIBCPP_THREAD_SAFETY_ANNOTATION(release_capability()) {__m_.unlock();}
+
+private:
+    lock_guard(lock_guard const&) = delete;
+    lock_guard& operator=(lock_guard const&) = delete;
+};
+
+template <class _Mutex>
+class _LIBCPP_TEMPLATE_VIS unique_lock
+{
+public:
+    typedef _Mutex mutex_type;
+
+private:
+    mutex_type* __m_;
+    bool __owns_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    unique_lock() _NOEXCEPT : __m_(nullptr), __owns_(false) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit unique_lock(mutex_type& __m)
+        : __m_(_VSTD::addressof(__m)), __owns_(true) {__m_->lock();}
+    _LIBCPP_INLINE_VISIBILITY
+    unique_lock(mutex_type& __m, defer_lock_t) _NOEXCEPT
+        : __m_(_VSTD::addressof(__m)), __owns_(false) {}
+    _LIBCPP_INLINE_VISIBILITY
+    unique_lock(mutex_type& __m, try_to_lock_t)
+        : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock()) {}
+    _LIBCPP_INLINE_VISIBILITY
+    unique_lock(mutex_type& __m, adopt_lock_t)
+        : __m_(_VSTD::addressof(__m)), __owns_(true) {}
+    template <class _Clock, class _Duration>
+    _LIBCPP_INLINE_VISIBILITY
+        unique_lock(mutex_type& __m, const chrono::time_point<_Clock, _Duration>& __t)
+            : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock_until(__t)) {}
+    template <class _Rep, class _Period>
+    _LIBCPP_INLINE_VISIBILITY
+        unique_lock(mutex_type& __m, const chrono::duration<_Rep, _Period>& __d)
+            : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock_for(__d)) {}
+    _LIBCPP_INLINE_VISIBILITY
+    ~unique_lock()
+    {
+        if (__owns_)
+            __m_->unlock();
+    }
+
+private:
+    unique_lock(unique_lock const&); // = delete;
+    unique_lock& operator=(unique_lock const&); // = delete;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    unique_lock(unique_lock&& __u) _NOEXCEPT
+        : __m_(__u.__m_), __owns_(__u.__owns_)
+        {__u.__m_ = nullptr; __u.__owns_ = false;}
+    _LIBCPP_INLINE_VISIBILITY
+    unique_lock& operator=(unique_lock&& __u) _NOEXCEPT
+        {
+            if (__owns_)
+                __m_->unlock();
+            __m_ = __u.__m_;
+            __owns_ = __u.__owns_;
+            __u.__m_ = nullptr;
+            __u.__owns_ = false;
+            return *this;
+        }
+
+    void lock();
+    bool try_lock();
+
+    template <class _Rep, class _Period>
+        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d);
+    template <class _Clock, class _Duration>
+        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
+
+    void unlock();
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(unique_lock& __u) _NOEXCEPT
+    {
+        _VSTD::swap(__m_, __u.__m_);
+        _VSTD::swap(__owns_, __u.__owns_);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    mutex_type* release() _NOEXCEPT
+    {
+        mutex_type* __m = __m_;
+        __m_ = nullptr;
+        __owns_ = false;
+        return __m;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool owns_lock() const _NOEXCEPT {return __owns_;}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit operator bool() const _NOEXCEPT {return __owns_;}
+    _LIBCPP_INLINE_VISIBILITY
+    mutex_type* mutex() const _NOEXCEPT {return __m_;}
+};
+
+template <class _Mutex>
+void
+unique_lock<_Mutex>::lock()
+{
+    if (__m_ == nullptr)
+        __throw_system_error(EPERM, "unique_lock::lock: references null mutex");
+    if (__owns_)
+        __throw_system_error(EDEADLK, "unique_lock::lock: already locked");
+    __m_->lock();
+    __owns_ = true;
+}
+
+template <class _Mutex>
+bool
+unique_lock<_Mutex>::try_lock()
+{
+    if (__m_ == nullptr)
+        __throw_system_error(EPERM, "unique_lock::try_lock: references null mutex");
+    if (__owns_)
+        __throw_system_error(EDEADLK, "unique_lock::try_lock: already locked");
+    __owns_ = __m_->try_lock();
+    return __owns_;
+}
+
+template <class _Mutex>
+template <class _Rep, class _Period>
+bool
+unique_lock<_Mutex>::try_lock_for(const chrono::duration<_Rep, _Period>& __d)
+{
+    if (__m_ == nullptr)
+        __throw_system_error(EPERM, "unique_lock::try_lock_for: references null mutex");
+    if (__owns_)
+        __throw_system_error(EDEADLK, "unique_lock::try_lock_for: already locked");
+    __owns_ = __m_->try_lock_for(__d);
+    return __owns_;
+}
+
+template <class _Mutex>
+template <class _Clock, class _Duration>
+bool
+unique_lock<_Mutex>::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
+{
+    if (__m_ == nullptr)
+        __throw_system_error(EPERM, "unique_lock::try_lock_until: references null mutex");
+    if (__owns_)
+        __throw_system_error(EDEADLK, "unique_lock::try_lock_until: already locked");
+    __owns_ = __m_->try_lock_until(__t);
+    return __owns_;
+}
+
+template <class _Mutex>
+void
+unique_lock<_Mutex>::unlock()
+{
+    if (!__owns_)
+        __throw_system_error(EPERM, "unique_lock::unlock: not locked");
+    __m_->unlock();
+    __owns_ = false;
+}
+
+template <class _Mutex>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y) _NOEXCEPT
+    {__x.swap(__y);}
+
+//enum class cv_status
+_LIBCPP_DECLARE_STRONG_ENUM(cv_status)
+{
+    no_timeout,
+    timeout
+};
+_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(cv_status)
+
+class _LIBCPP_TYPE_VIS condition_variable
+{
+    __libcpp_condvar_t __cv_ = _LIBCPP_CONDVAR_INITIALIZER;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR condition_variable() _NOEXCEPT = default;
+
+#ifdef _LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION
+    ~condition_variable() = default;
+#else
+    ~condition_variable();
+#endif
+
+    condition_variable(const condition_variable&) = delete;
+    condition_variable& operator=(const condition_variable&) = delete;
+
+    void notify_one() _NOEXCEPT;
+    void notify_all() _NOEXCEPT;
+
+    void wait(unique_lock<mutex>& __lk) _NOEXCEPT;
+    template <class _Predicate>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        void wait(unique_lock<mutex>& __lk, _Predicate __pred);
+
+    template <class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        cv_status
+        wait_until(unique_lock<mutex>& __lk,
+                   const chrono::time_point<_Clock, _Duration>& __t);
+
+    template <class _Clock, class _Duration, class _Predicate>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        bool
+        wait_until(unique_lock<mutex>& __lk,
+                   const chrono::time_point<_Clock, _Duration>& __t,
+                   _Predicate __pred);
+
+    template <class _Rep, class _Period>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        cv_status
+        wait_for(unique_lock<mutex>& __lk,
+                 const chrono::duration<_Rep, _Period>& __d);
+
+    template <class _Rep, class _Period, class _Predicate>
+        bool
+        _LIBCPP_INLINE_VISIBILITY
+        wait_for(unique_lock<mutex>& __lk,
+                 const chrono::duration<_Rep, _Period>& __d,
+                 _Predicate __pred);
+
+    typedef __libcpp_condvar_t* native_handle_type;
+    _LIBCPP_INLINE_VISIBILITY native_handle_type native_handle() {return &__cv_;}
+
+private:
+    void __do_timed_wait(unique_lock<mutex>& __lk,
+       chrono::time_point<chrono::system_clock, chrono::nanoseconds>) _NOEXCEPT;
+#if defined(_LIBCPP_HAS_COND_CLOCKWAIT)
+    void __do_timed_wait(unique_lock<mutex>& __lk,
+       chrono::time_point<chrono::steady_clock, chrono::nanoseconds>) _NOEXCEPT;
+#endif
+    template <class _Clock>
+    void __do_timed_wait(unique_lock<mutex>& __lk,
+       chrono::time_point<_Clock, chrono::nanoseconds>) _NOEXCEPT;
+};
+#endif // !_LIBCPP_HAS_NO_THREADS
+
+template <class _Rep, class _Period>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_floating_point<_Rep>::value,
+    chrono::nanoseconds
+>::type
+__safe_nanosecond_cast(chrono::duration<_Rep, _Period> __d)
+{
+    using namespace chrono;
+    using __ratio = ratio_divide<_Period, nano>;
+    using __ns_rep = nanoseconds::rep;
+    _Rep __result_float = __d.count() * __ratio::num / __ratio::den;
+
+    _Rep __result_max = numeric_limits<__ns_rep>::max();
+    if (__result_float >= __result_max) {
+        return nanoseconds::max();
+    }
+
+    _Rep __result_min = numeric_limits<__ns_rep>::min();
+    if (__result_float <= __result_min) {
+        return nanoseconds::min();
+    }
+
+    return nanoseconds(static_cast<__ns_rep>(__result_float));
+}
+
+template <class _Rep, class _Period>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    !is_floating_point<_Rep>::value,
+    chrono::nanoseconds
+>::type
+__safe_nanosecond_cast(chrono::duration<_Rep, _Period> __d)
+{
+    using namespace chrono;
+    if (__d.count() == 0) {
+        return nanoseconds(0);
+    }
+
+    using __ratio = ratio_divide<_Period, nano>;
+    using __ns_rep = nanoseconds::rep;
+    __ns_rep __result_max = numeric_limits<__ns_rep>::max();
+    if (__d.count() > 0 && __d.count() > __result_max / __ratio::num) {
+        return nanoseconds::max();
+    }
+
+    __ns_rep __result_min = numeric_limits<__ns_rep>::min();
+    if (__d.count() < 0 && __d.count() < __result_min / __ratio::num) {
+        return nanoseconds::min();
+    }
+
+    __ns_rep __result = __d.count() * __ratio::num / __ratio::den;
+    if (__result == 0) {
+        return nanoseconds(1);
+    }
+
+    return nanoseconds(__result);
+}
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+template <class _Predicate>
+void
+condition_variable::wait(unique_lock<mutex>& __lk, _Predicate __pred)
+{
+    while (!__pred())
+        wait(__lk);
+}
+
+template <class _Clock, class _Duration>
+cv_status
+condition_variable::wait_until(unique_lock<mutex>& __lk,
+                               const chrono::time_point<_Clock, _Duration>& __t)
+{
+    using namespace chrono;
+    using __clock_tp_ns = time_point<_Clock, nanoseconds>;
+
+    typename _Clock::time_point __now = _Clock::now();
+    if (__t <= __now)
+        return cv_status::timeout;
+
+    __clock_tp_ns __t_ns = __clock_tp_ns(_VSTD::__safe_nanosecond_cast(__t.time_since_epoch()));
+
+    __do_timed_wait(__lk, __t_ns);
+    return _Clock::now() < __t ? cv_status::no_timeout : cv_status::timeout;
+}
+
+template <class _Clock, class _Duration, class _Predicate>
+bool
+condition_variable::wait_until(unique_lock<mutex>& __lk,
+                   const chrono::time_point<_Clock, _Duration>& __t,
+                   _Predicate __pred)
+{
+    while (!__pred())
+    {
+        if (wait_until(__lk, __t) == cv_status::timeout)
+            return __pred();
+    }
+    return true;
+}
+
+template <class _Rep, class _Period>
+cv_status
+condition_variable::wait_for(unique_lock<mutex>& __lk,
+                             const chrono::duration<_Rep, _Period>& __d)
+{
+    using namespace chrono;
+    if (__d <= __d.zero())
+        return cv_status::timeout;
+    using __ns_rep = nanoseconds::rep;
+    steady_clock::time_point __c_now = steady_clock::now();
+
+#if defined(_LIBCPP_HAS_COND_CLOCKWAIT)
+    using __clock_tp_ns = time_point<steady_clock, nanoseconds>;
+    __ns_rep __now_count_ns = _VSTD::__safe_nanosecond_cast(__c_now.time_since_epoch()).count();
+#else
+    using __clock_tp_ns = time_point<system_clock, nanoseconds>;
+    __ns_rep __now_count_ns = _VSTD::__safe_nanosecond_cast(system_clock::now().time_since_epoch()).count();
+#endif
+
+    __ns_rep __d_ns_count = _VSTD::__safe_nanosecond_cast(__d).count();
+
+    if (__now_count_ns > numeric_limits<__ns_rep>::max() - __d_ns_count) {
+        __do_timed_wait(__lk, __clock_tp_ns::max());
+    } else {
+        __do_timed_wait(__lk, __clock_tp_ns(nanoseconds(__now_count_ns + __d_ns_count)));
+    }
+
+    return steady_clock::now() - __c_now < __d ? cv_status::no_timeout :
+                                                 cv_status::timeout;
+}
+
+template <class _Rep, class _Period, class _Predicate>
+inline
+bool
+condition_variable::wait_for(unique_lock<mutex>& __lk,
+                             const chrono::duration<_Rep, _Period>& __d,
+                             _Predicate __pred)
+{
+    return wait_until(__lk, chrono::steady_clock::now() + __d,
+                      _VSTD::move(__pred));
+}
+
+#if defined(_LIBCPP_HAS_COND_CLOCKWAIT)
+inline
+void
+condition_variable::__do_timed_wait(unique_lock<mutex>& __lk,
+     chrono::time_point<chrono::steady_clock, chrono::nanoseconds> __tp) _NOEXCEPT
+{
+    using namespace chrono;
+    if (!__lk.owns_lock())
+        __throw_system_error(EPERM,
+                            "condition_variable::timed wait: mutex not locked");
+    nanoseconds __d = __tp.time_since_epoch();
+    timespec __ts;
+    seconds __s = duration_cast<seconds>(__d);
+    using __ts_sec = decltype(__ts.tv_sec);
+    const __ts_sec __ts_sec_max = numeric_limits<__ts_sec>::max();
+    if (__s.count() < __ts_sec_max)
+    {
+        __ts.tv_sec = static_cast<__ts_sec>(__s.count());
+        __ts.tv_nsec = (__d - __s).count();
+    }
+    else
+    {
+        __ts.tv_sec = __ts_sec_max;
+        __ts.tv_nsec = giga::num - 1;
+    }
+    int __ec = pthread_cond_clockwait(&__cv_, __lk.mutex()->native_handle(), CLOCK_MONOTONIC, &__ts);
+    if (__ec != 0 && __ec != ETIMEDOUT)
+        __throw_system_error(__ec, "condition_variable timed_wait failed");
+}
+#endif // _LIBCPP_HAS_COND_CLOCKWAIT
+
+template <class _Clock>
+inline
+void
+condition_variable::__do_timed_wait(unique_lock<mutex>& __lk,
+     chrono::time_point<_Clock, chrono::nanoseconds> __tp) _NOEXCEPT
+{
+    wait_for(__lk, __tp - _Clock::now());
+}
+
+#endif // !_LIBCPP_HAS_NO_THREADS
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___MUTEX_BASE
diff --git a/contrib/libs/cxxsupp/libcxx/include/__node_handle b/contrib/libs/cxxsupp/libcxx/include/__node_handle
new file mode 100644
index 00000000000..f313409bb68
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__node_handle
@@ -0,0 +1,253 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___NODE_HANDLE
+#define _LIBCPP___NODE_HANDLE
+
+/*
+
+template<unspecified>
+class node-handle {
+public:
+  using value_type     = see below;     // not present for map containers
+  using key_type       = see below;     // not present for set containers
+  using mapped_type    = see below;     // not present for set containers
+  using allocator_type = see below;
+
+private:
+  using container_node_type = unspecified;                  // exposition only
+  using ator_traits = allocator_traits<allocator_type>;     // exposition only
+
+  typename ator_traits::template
+    rebind_traits<container_node_type>::pointer ptr_;       // exposition only
+  optional<allocator_type> alloc_;                          // exposition only
+
+public:
+  // [container.node.cons], constructors, copy, and assignment
+  constexpr node-handle() noexcept : ptr_(), alloc_() {}
+  node-handle(node-handle&&) noexcept;
+  node-handle& operator=(node-handle&&);
+
+  // [container.node.dtor], destructor
+  ~node-handle();
+
+  // [container.node.observers], observers
+  value_type& value() const;            // not present for map containers
+  key_type& key() const;                // not present for set containers
+  mapped_type& mapped() const;          // not present for set containers
+
+  allocator_type get_allocator() const;
+  explicit operator bool() const noexcept;
+  [[nodiscard]] bool empty() const noexcept; // nodiscard since C++20
+
+  // [container.node.modifiers], modifiers
+  void swap(node-handle&)
+    noexcept(ator_traits::propagate_on_container_swap::value ||
+             ator_traits::is_always_equal::value);
+
+  friend void swap(node-handle& x, node-handle& y) noexcept(noexcept(x.swap(y))) {
+    x.swap(y);
+  }
+};
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <memory>
+#include <optional>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+// Specialized in __tree & __hash_table for their _NodeType.
+template <class _NodeType, class _Alloc>
+struct __generic_container_node_destructor;
+
+template <class _NodeType, class _Alloc,
+          template <class, class> class _MapOrSetSpecifics>
+class _LIBCPP_TEMPLATE_VIS __basic_node_handle
+    : public _MapOrSetSpecifics<
+          _NodeType,
+          __basic_node_handle<_NodeType, _Alloc, _MapOrSetSpecifics>>
+{
+    template <class _Tp, class _Compare, class _Allocator>
+        friend class __tree;
+    template <class _Tp, class _Hash, class _Equal, class _Allocator>
+        friend class __hash_table;
+    friend struct _MapOrSetSpecifics<
+        _NodeType, __basic_node_handle<_NodeType, _Alloc, _MapOrSetSpecifics>>;
+
+    typedef allocator_traits<_Alloc> __alloc_traits;
+    typedef typename __rebind_pointer<typename __alloc_traits::void_pointer,
+                                      _NodeType>::type
+        __node_pointer_type;
+
+public:
+    typedef _Alloc allocator_type;
+
+private:
+    __node_pointer_type __ptr_ = nullptr;
+    optional<allocator_type> __alloc_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __release_ptr()
+    {
+        __ptr_ = nullptr;
+        __alloc_ = _VSTD::nullopt;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __destroy_node_pointer()
+    {
+        if (__ptr_ != nullptr)
+        {
+            typedef typename __allocator_traits_rebind<
+                allocator_type, _NodeType>::type __node_alloc_type;
+            __node_alloc_type __alloc(*__alloc_);
+            __generic_container_node_destructor<_NodeType, __node_alloc_type>(
+                __alloc, true)(__ptr_);
+            __ptr_ = nullptr;
+        }
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __basic_node_handle(__node_pointer_type __ptr,
+                        allocator_type const& __alloc)
+            : __ptr_(__ptr), __alloc_(__alloc)
+    {
+    }
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __basic_node_handle() = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __basic_node_handle(__basic_node_handle&& __other) noexcept
+            : __ptr_(__other.__ptr_),
+              __alloc_(_VSTD::move(__other.__alloc_))
+    {
+        __other.__ptr_ = nullptr;
+        __other.__alloc_ = _VSTD::nullopt;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __basic_node_handle& operator=(__basic_node_handle&& __other)
+    {
+        _LIBCPP_ASSERT(
+            __alloc_ == _VSTD::nullopt ||
+            __alloc_traits::propagate_on_container_move_assignment::value ||
+            __alloc_ == __other.__alloc_,
+            "node_type with incompatible allocator passed to "
+            "node_type::operator=(node_type&&)");
+
+        __destroy_node_pointer();
+        __ptr_ = __other.__ptr_;
+
+        if (__alloc_traits::propagate_on_container_move_assignment::value ||
+            __alloc_ == _VSTD::nullopt)
+            __alloc_ = _VSTD::move(__other.__alloc_);
+
+        __other.__ptr_ = nullptr;
+        __other.__alloc_ = _VSTD::nullopt;
+
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const { return *__alloc_; }
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit operator bool() const { return __ptr_ != nullptr; }
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool empty() const { return __ptr_ == nullptr; }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(__basic_node_handle& __other) noexcept(
+        __alloc_traits::propagate_on_container_swap::value ||
+        __alloc_traits::is_always_equal::value)
+    {
+        using _VSTD::swap;
+        swap(__ptr_, __other.__ptr_);
+        if (__alloc_traits::propagate_on_container_swap::value ||
+            __alloc_ == _VSTD::nullopt || __other.__alloc_ == _VSTD::nullopt)
+            swap(__alloc_, __other.__alloc_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    friend void swap(__basic_node_handle& __a, __basic_node_handle& __b)
+        noexcept(noexcept(__a.swap(__b))) { __a.swap(__b); }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~__basic_node_handle()
+    {
+        __destroy_node_pointer();
+    }
+};
+
+template <class _NodeType, class _Derived>
+struct __set_node_handle_specifics
+{
+    typedef typename _NodeType::__node_value_type value_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    value_type& value() const
+    {
+        return static_cast<_Derived const*>(this)->__ptr_->__value_;
+    }
+};
+
+template <class _NodeType, class _Derived>
+struct __map_node_handle_specifics
+{
+    typedef typename _NodeType::__node_value_type::key_type key_type;
+    typedef typename _NodeType::__node_value_type::mapped_type mapped_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    key_type& key() const
+    {
+        return static_cast<_Derived const*>(this)->
+            __ptr_->__value_.__ref().first;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    mapped_type& mapped() const
+    {
+        return static_cast<_Derived const*>(this)->
+            __ptr_->__value_.__ref().second;
+    }
+};
+
+template <class _NodeType, class _Alloc>
+using __set_node_handle =
+    __basic_node_handle< _NodeType, _Alloc, __set_node_handle_specifics>;
+
+template <class _NodeType, class _Alloc>
+using __map_node_handle =
+    __basic_node_handle< _NodeType, _Alloc, __map_node_handle_specifics>;
+
+template <class _Iterator, class _NodeType>
+struct _LIBCPP_TEMPLATE_VIS __insert_return_type
+{
+    _Iterator position;
+    bool inserted;
+    _NodeType node;
+};
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif  // _LIBCPP___NODE_HANDLE
diff --git a/contrib/libs/cxxsupp/libcxx/include/__nullptr b/contrib/libs/cxxsupp/libcxx/include/__nullptr
new file mode 100644
index 00000000000..e1475116423
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__nullptr
@@ -0,0 +1,61 @@
+// -*- C++ -*-
+//===--------------------------- __nullptr --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_NULLPTR
+#define _LIBCPP_NULLPTR
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_HAS_NO_NULLPTR
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+struct _LIBCPP_TEMPLATE_VIS nullptr_t
+{
+    void* __lx;
+
+    struct __nat {int __for_bool_;};
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR nullptr_t() : __lx(0) {}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR nullptr_t(int __nat::*) : __lx(0) {}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR operator int __nat::*() const {return 0;}
+
+    template <class _Tp>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+        operator _Tp* () const {return 0;}
+
+    template <class _Tp, class _Up>
+        _LIBCPP_INLINE_VISIBILITY
+        operator _Tp _Up::* () const {return 0;}
+
+    friend _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR bool operator==(nullptr_t, nullptr_t) {return true;}
+    friend _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR bool operator!=(nullptr_t, nullptr_t) {return false;}
+};
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR nullptr_t __get_nullptr_t() {return nullptr_t(0);}
+
+#define nullptr _VSTD::__get_nullptr_t()
+
+_LIBCPP_END_NAMESPACE_STD
+
+#else  // _LIBCPP_HAS_NO_NULLPTR
+
+namespace std
+{
+    typedef decltype(nullptr) nullptr_t;
+}
+
+#endif // _LIBCPP_HAS_NO_NULLPTR
+
+#endif // _LIBCPP_NULLPTR
diff --git a/contrib/libs/cxxsupp/libcxx/include/__random/uniform_int_distribution.h b/contrib/libs/cxxsupp/libcxx/include/__random/uniform_int_distribution.h
new file mode 100644
index 00000000000..a7cfa1ec730
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__random/uniform_int_distribution.h
@@ -0,0 +1,316 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___RANDOM_UNIFORM_INT_DISTRIBUTION_H
+#define _LIBCPP___RANDOM_UNIFORM_INT_DISTRIBUTION_H
+
+#include <__bits>
+#include <__config>
+#include <cstddef>
+#include <cstdint>
+#include <iosfwd>
+#include <limits>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// __independent_bits_engine
+
+template <unsigned long long _Xp, size_t _Rp>
+struct __log2_imp
+{
+    static const size_t value = _Xp & ((unsigned long long)(1) << _Rp) ? _Rp
+                                           : __log2_imp<_Xp, _Rp - 1>::value;
+};
+
+template <unsigned long long _Xp>
+struct __log2_imp<_Xp, 0>
+{
+    static const size_t value = 0;
+};
+
+template <size_t _Rp>
+struct __log2_imp<0, _Rp>
+{
+    static const size_t value = _Rp + 1;
+};
+
+template <class _UIntType, _UIntType _Xp>
+struct __log2
+{
+    static const size_t value = __log2_imp<_Xp,
+                                         sizeof(_UIntType) * __CHAR_BIT__ - 1>::value;
+};
+
+template<class _Engine, class _UIntType>
+class __independent_bits_engine
+{
+public:
+    // types
+    typedef _UIntType result_type;
+
+private:
+    typedef typename _Engine::result_type _Engine_result_type;
+    typedef typename conditional
+        <
+            sizeof(_Engine_result_type) <= sizeof(result_type),
+                result_type,
+                _Engine_result_type
+        >::type _Working_result_type;
+
+    _Engine& __e_;
+    size_t __w_;
+    size_t __w0_;
+    size_t __n_;
+    size_t __n0_;
+    _Working_result_type __y0_;
+    _Working_result_type __y1_;
+    _Engine_result_type __mask0_;
+    _Engine_result_type __mask1_;
+
+#ifdef _LIBCPP_CXX03_LANG
+    static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min
+                                          + _Working_result_type(1);
+#else
+    static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min()
+                                                      + _Working_result_type(1);
+#endif
+    static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;
+    static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
+    static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;
+
+public:
+    // constructors and seeding functions
+    __independent_bits_engine(_Engine& __e, size_t __w);
+
+    // generating functions
+    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
+
+private:
+    result_type __eval(false_type);
+    result_type __eval(true_type);
+};
+
+template<class _Engine, class _UIntType>
+__independent_bits_engine<_Engine, _UIntType>
+    ::__independent_bits_engine(_Engine& __e, size_t __w)
+        : __e_(__e),
+          __w_(__w)
+{
+    __n_ = __w_ / __m + (__w_ % __m != 0);
+    __w0_ = __w_ / __n_;
+    if (_Rp == 0)
+        __y0_ = _Rp;
+    else if (__w0_ < _WDt)
+        __y0_ = (_Rp >> __w0_) << __w0_;
+    else
+        __y0_ = 0;
+    if (_Rp - __y0_ > __y0_ / __n_)
+    {
+        ++__n_;
+        __w0_ = __w_ / __n_;
+        if (__w0_ < _WDt)
+            __y0_ = (_Rp >> __w0_) << __w0_;
+        else
+            __y0_ = 0;
+    }
+    __n0_ = __n_ - __w_ % __n_;
+    if (__w0_ < _WDt - 1)
+        __y1_ = (_Rp >> (__w0_ + 1)) << (__w0_ + 1);
+    else
+        __y1_ = 0;
+    __mask0_ = __w0_ > 0 ? _Engine_result_type(~0) >> (_EDt - __w0_) :
+                          _Engine_result_type(0);
+    __mask1_ = __w0_ < _EDt - 1 ?
+                               _Engine_result_type(~0) >> (_EDt - (__w0_ + 1)) :
+                               _Engine_result_type(~0);
+}
+
+template<class _Engine, class _UIntType>
+inline
+_UIntType
+__independent_bits_engine<_Engine, _UIntType>::__eval(false_type)
+{
+    return static_cast<result_type>(__e_() & __mask0_);
+}
+
+template<class _Engine, class _UIntType>
+_UIntType
+__independent_bits_engine<_Engine, _UIntType>::__eval(true_type)
+{
+    const size_t _WRt = numeric_limits<result_type>::digits;
+    result_type _Sp = 0;
+    for (size_t __k = 0; __k < __n0_; ++__k)
+    {
+        _Engine_result_type __u;
+        do
+        {
+            __u = __e_() - _Engine::min();
+        } while (__u >= __y0_);
+        if (__w0_ < _WRt)
+            _Sp <<= __w0_;
+        else
+            _Sp = 0;
+        _Sp += __u & __mask0_;
+    }
+    for (size_t __k = __n0_; __k < __n_; ++__k)
+    {
+        _Engine_result_type __u;
+        do
+        {
+            __u = __e_() - _Engine::min();
+        } while (__u >= __y1_);
+        if (__w0_ < _WRt - 1)
+            _Sp <<= __w0_ + 1;
+        else
+            _Sp = 0;
+        _Sp += __u & __mask1_;
+    }
+    return _Sp;
+}
+
+template<class _IntType = int>
+class uniform_int_distribution
+{
+public:
+    // types
+    typedef _IntType result_type;
+
+    class param_type
+    {
+        result_type __a_;
+        result_type __b_;
+    public:
+        typedef uniform_int_distribution distribution_type;
+
+        explicit param_type(result_type __a = 0,
+                            result_type __b = numeric_limits<result_type>::max())
+            : __a_(__a), __b_(__b) {}
+
+        result_type a() const {return __a_;}
+        result_type b() const {return __b_;}
+
+        friend bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
+        friend bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructors and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    uniform_int_distribution() : uniform_int_distribution(0) {}
+    explicit uniform_int_distribution(
+        result_type __a, result_type __b = numeric_limits<result_type>::max())
+        : __p_(param_type(__a, __b)) {}
+#else
+    explicit uniform_int_distribution(
+        result_type __a = 0,
+        result_type __b = numeric_limits<result_type>::max())
+        : __p_(param_type(__a, __b)) {}
+#endif
+    explicit uniform_int_distribution(const param_type& __p) : __p_(__p) {}
+    void reset() {}
+
+    // generating functions
+    template<class _URNG> result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    result_type a() const {return __p_.a();}
+    result_type b() const {return __p_.b();}
+
+    param_type param() const {return __p_;}
+    void param(const param_type& __p) {__p_ = __p;}
+
+    result_type min() const {return a();}
+    result_type max() const {return b();}
+
+    friend bool operator==(const uniform_int_distribution& __x,
+                           const uniform_int_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend bool operator!=(const uniform_int_distribution& __x,
+                           const uniform_int_distribution& __y)
+            {return !(__x == __y);}
+};
+
+template<class _IntType>
+template<class _URNG>
+typename uniform_int_distribution<_IntType>::result_type
+uniform_int_distribution<_IntType>::operator()(_URNG& __g, const param_type& __p)
+_LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+{
+    typedef typename conditional<sizeof(result_type) <= sizeof(uint32_t),
+                                            uint32_t, uint64_t>::type _UIntType;
+    const _UIntType _Rp = _UIntType(__p.b()) - _UIntType(__p.a()) + _UIntType(1);
+    if (_Rp == 1)
+        return __p.a();
+    const size_t _Dt = numeric_limits<_UIntType>::digits;
+    typedef __independent_bits_engine<_URNG, _UIntType> _Eng;
+    if (_Rp == 0)
+        return static_cast<result_type>(_Eng(__g, _Dt)());
+    size_t __w = _Dt - __libcpp_clz(_Rp) - 1;
+    if ((_Rp & (numeric_limits<_UIntType>::max() >> (_Dt - __w))) != 0)
+        ++__w;
+    _Eng __e(__g, __w);
+    _UIntType __u;
+    do
+    {
+        __u = __e();
+    } while (__u >= _Rp);
+    return static_cast<result_type>(__u + __p.a());
+}
+
+template <class _CharT, class _Traits, class _IT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const uniform_int_distribution<_IT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _Ostream;
+    __os.flags(_Ostream::dec | _Ostream::left);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    return __os << __x.a() << __sp << __x.b();
+}
+
+template <class _CharT, class _Traits, class _IT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           uniform_int_distribution<_IT>& __x)
+{
+    typedef uniform_int_distribution<_IT> _Eng;
+    typedef typename _Eng::result_type result_type;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    result_type __a;
+    result_type __b;
+    __is >> __a >> __b;
+    if (!__is.fail())
+        __x.param(param_type(__a, __b));
+    return __is;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___RANDOM_UNIFORM_INT_DISTRIBUTION_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/access.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/access.h
new file mode 100644
index 00000000000..559711359c5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/access.h
@@ -0,0 +1,218 @@
+// -*- C++ -*-
+//===------------------------ __ranges/access.h ---------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_ACCESS_H
+#define _LIBCPP___RANGES_ACCESS_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/readable_traits.h>
+#include <__ranges/enable_borrowed_range.h>
+#include <__utility/as_const.h>
+#include <__utility/decay_copy.h>
+#include <__utility/forward.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+// clang-format off
+
+namespace ranges {
+  template <class _Tp>
+  concept __can_borrow =
+      is_lvalue_reference_v<_Tp> || enable_borrowed_range<remove_cvref_t<_Tp> >;
+
+  template<class _Tp>
+  concept __is_complete = requires { sizeof(_Tp); };
+} // namespace ranges
+
+// [range.access.begin]
+namespace ranges::__begin {
+  template <class _Tp>
+  concept __member_begin =
+    __can_borrow<_Tp> &&
+    requires(_Tp&& __t) {
+      { _VSTD::__decay_copy(__t.begin()) } -> input_or_output_iterator;
+    };
+
+  void begin(auto&) = delete;
+  void begin(const auto&) = delete;
+
+  template <class _Tp>
+  concept __unqualified_begin =
+    !__member_begin<_Tp> &&
+    __can_borrow<_Tp> &&
+    __class_or_enum<remove_cvref_t<_Tp> > &&
+    requires(_Tp && __t) {
+      { _VSTD::__decay_copy(begin(__t)) } -> input_or_output_iterator;
+    };
+
+  struct __fn {
+    template <class _Tp>
+    requires is_array_v<remove_cv_t<_Tp>>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp& __t) const noexcept {
+      constexpr bool __complete = __is_complete<iter_value_t<_Tp> >;
+      if constexpr (__complete) { // used to disable cryptic diagnostic
+        return __t + 0;
+      }
+      else {
+        static_assert(__complete, "`std::ranges::begin` is SFINAE-unfriendly on arrays of an incomplete type.");
+      }
+    }
+
+    template <class _Tp>
+    requires __member_begin<_Tp>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
+    noexcept(noexcept(_VSTD::__decay_copy(__t.begin())))
+    {
+      return __t.begin();
+    }
+
+    template <class _Tp>
+    requires __unqualified_begin<_Tp>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
+    noexcept(noexcept(_VSTD::__decay_copy(begin(__t))))
+    {
+      return begin(__t);
+    }
+
+    void operator()(auto&&) const = delete;
+  };
+} // namespace ranges::__begin
+
+namespace ranges {
+  inline namespace __cpo {
+    inline constexpr auto begin = __begin::__fn{};
+  } // namespace __cpo
+
+  template <class _Tp>
+  using iterator_t = decltype(ranges::begin(declval<_Tp&>()));
+} // namespace ranges
+
+// [range.access.end]
+namespace ranges::__end {
+  template <class _Tp>
+  concept __member_end =
+    __can_borrow<_Tp> &&
+    requires(_Tp&& __t) {
+      typename iterator_t<_Tp>;
+      { _VSTD::__decay_copy(_VSTD::forward<_Tp>(__t).end()) } -> sentinel_for<iterator_t<_Tp> >;
+    };
+
+  void end(auto&) = delete;
+  void end(const auto&) = delete;
+
+  template <class _Tp>
+  concept __unqualified_end =
+    !__member_end<_Tp> &&
+    __can_borrow<_Tp> &&
+    __class_or_enum<remove_cvref_t<_Tp> > &&
+    requires(_Tp && __t) {
+      typename iterator_t<_Tp>;
+      { _VSTD::__decay_copy(end(_VSTD::forward<_Tp>(__t))) } -> sentinel_for<iterator_t<_Tp> >;
+    };
+
+  class __fn {
+  public:
+    template <class _Tp, size_t _Np>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp (&__t)[_Np]) const noexcept {
+      constexpr bool __complete = __is_complete<remove_cv_t<_Tp> >;
+      if constexpr (__complete) { // used to disable cryptic diagnostic
+        return __t + _Np;
+      }
+      else {
+        static_assert(__complete, "`std::ranges::end` is SFINAE-unfriendly on arrays of an incomplete type.");
+      }
+    }
+
+    template <class _Tp>
+    requires __member_end<_Tp>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
+    noexcept(noexcept(_VSTD::__decay_copy(__t.end())))
+    {
+      return _VSTD::forward<_Tp>(__t).end();
+    }
+
+    template <class _Tp>
+    requires __unqualified_end<_Tp>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
+    noexcept(noexcept(_VSTD::__decay_copy(end(__t))))
+    {
+      return end(__t);
+    }
+
+    void operator()(auto&&) const = delete;
+  };
+} // namespace ranges::__end
+
+namespace ranges::inline __cpo {
+  inline constexpr auto end = __end::__fn{};
+} // namespace ranges::__cpo
+
+namespace ranges::__cbegin {
+  struct __fn {
+    template <class _Tp>
+    requires invocable<decltype(ranges::begin), _Tp const&>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp& __t) const
+    noexcept(noexcept(ranges::begin(_VSTD::as_const(__t))))
+    {
+      return ranges::begin(_VSTD::as_const(__t));
+    }
+
+    template <class _Tp>
+    requires is_rvalue_reference_v<_Tp> && invocable<decltype(ranges::begin), _Tp const&&>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
+    noexcept(noexcept(ranges::begin(static_cast<_Tp const&&>(__t))))
+    {
+      return ranges::begin(static_cast<_Tp const&&>(__t));
+    }
+  };
+} // namespace ranges::__cbegin
+
+namespace ranges::inline __cpo {
+  inline constexpr auto cbegin = __cbegin::__fn{};
+} // namespace ranges::__cpo
+
+namespace ranges::__cend {
+  struct __fn {
+    template <class _Tp>
+    requires invocable<decltype(ranges::end), _Tp const&>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp& __t) const
+    noexcept(noexcept(ranges::end(_VSTD::as_const(__t))))
+    {
+      return ranges::end(_VSTD::as_const(__t));
+    }
+
+    template <class _Tp>
+    requires is_rvalue_reference_v<_Tp> && invocable<decltype(ranges::end), _Tp const&&>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
+    noexcept(noexcept(ranges::end(static_cast<_Tp const&&>(__t))))
+    {
+      return ranges::end(static_cast<_Tp const&&>(__t));
+    }
+  };
+} // namespace ranges::__cend
+
+namespace ranges::inline __cpo {
+  inline constexpr auto cend = __cend::__fn{};
+} // namespace ranges::__cpo
+
+// clang-format off
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_ACCESS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/all.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/all.h
new file mode 100644
index 00000000000..affe13ee086
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/all.h
@@ -0,0 +1,82 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_ALL_H
+#define _LIBCPP___RANGES_ALL_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/iterator_traits.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/range_adaptor.h>
+#include <__ranges/ref_view.h>
+#include <__ranges/subrange.h>
+#include <__utility/decay_copy.h>
+#include <__utility/declval.h>
+#include <__utility/forward.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges::views {
+
+namespace __all {
+  struct __fn : __range_adaptor_closure<__fn> {
+    template<class _Tp>
+      requires ranges::view<decay_t<_Tp>>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Tp&& __t) const
+      noexcept(noexcept(_VSTD::__decay_copy(_VSTD::forward<_Tp>(__t))))
+    {
+      return _VSTD::forward<_Tp>(__t);
+    }
+
+    template<class _Tp>
+      requires (!ranges::view<decay_t<_Tp>>) &&
+               requires (_Tp&& __t) { ranges::ref_view{_VSTD::forward<_Tp>(__t)}; }
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Tp&& __t) const
+      noexcept(noexcept(ranges::ref_view{_VSTD::forward<_Tp>(__t)}))
+    {
+      return ranges::ref_view{_VSTD::forward<_Tp>(__t)};
+    }
+
+    template<class _Tp>
+      requires (!ranges::view<decay_t<_Tp>> &&
+                !requires (_Tp&& __t) { ranges::ref_view{_VSTD::forward<_Tp>(__t)}; } &&
+                 requires (_Tp&& __t) { ranges::subrange{_VSTD::forward<_Tp>(__t)}; })
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Tp&& __t) const
+      noexcept(noexcept(ranges::subrange{_VSTD::forward<_Tp>(__t)}))
+    {
+      return ranges::subrange{_VSTD::forward<_Tp>(__t)};
+    }
+  };
+}
+
+inline namespace __cpo {
+  inline constexpr auto all = __all::__fn{};
+} // namespace __cpo
+
+template<ranges::viewable_range _Range>
+using all_t = decltype(views::all(declval<_Range>()));
+
+} // namespace ranges::views
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_ALL_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/common_view.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/common_view.h
new file mode 100644
index 00000000000..a58554f66e5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/common_view.h
@@ -0,0 +1,135 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_COMMON_VIEW_H
+#define _LIBCPP___RANGES_COMMON_VIEW_H
+
+#include <__config>
+#include <__iterator/common_iterator.h>
+#include <__iterator/iterator_traits.h>
+#include <__ranges/access.h>
+#include <__ranges/all.h>
+#include <__ranges/concepts.h>
+#include <__ranges/enable_borrowed_range.h>
+#include <__ranges/range_adaptor.h>
+#include <__ranges/size.h>
+#include <__ranges/view_interface.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+
+template<view _View>
+  requires (!common_range<_View> && copyable<iterator_t<_View>>)
+class common_view : public view_interface<common_view<_View>> {
+  _View __base_ = _View();
+
+public:
+  _LIBCPP_HIDE_FROM_ABI
+  common_view() requires default_initializable<_View> = default;
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr explicit common_view(_View __v) : __base_(_VSTD::move(__v)) { }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _View base() const& requires copy_constructible<_View> { return __base_; }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _View base() && { return _VSTD::move(__base_); }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto begin() {
+    if constexpr (random_access_range<_View> && sized_range<_View>)
+      return ranges::begin(__base_);
+    else
+      return common_iterator<iterator_t<_View>, sentinel_t<_View>>(ranges::begin(__base_));
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto begin() const requires range<const _View> {
+    if constexpr (random_access_range<const _View> && sized_range<const _View>)
+      return ranges::begin(__base_);
+    else
+      return common_iterator<iterator_t<const _View>, sentinel_t<const _View>>(ranges::begin(__base_));
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto end() {
+    if constexpr (random_access_range<_View> && sized_range<_View>)
+      return ranges::begin(__base_) + ranges::size(__base_);
+    else
+      return common_iterator<iterator_t<_View>, sentinel_t<_View>>(ranges::end(__base_));
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto end() const requires range<const _View> {
+    if constexpr (random_access_range<const _View> && sized_range<const _View>)
+      return ranges::begin(__base_) + ranges::size(__base_);
+    else
+      return common_iterator<iterator_t<const _View>, sentinel_t<const _View>>(ranges::end(__base_));
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto size() requires sized_range<_View> {
+    return ranges::size(__base_);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto size() const requires sized_range<const _View> {
+    return ranges::size(__base_);
+  }
+};
+
+template<class _Range>
+common_view(_Range&&)
+  -> common_view<views::all_t<_Range>>;
+
+template<class _View>
+inline constexpr bool enable_borrowed_range<common_view<_View>> = enable_borrowed_range<_View>;
+
+namespace views {
+namespace __common {
+  struct __fn : __range_adaptor_closure<__fn> {
+    template<class _Range>
+      requires common_range<_Range>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Range&& __range) const
+      noexcept(noexcept(views::all(_VSTD::forward<_Range>(__range))))
+      -> decltype(      views::all(_VSTD::forward<_Range>(__range)))
+      { return          views::all(_VSTD::forward<_Range>(__range)); }
+
+    template<class _Range>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Range&& __range) const
+      noexcept(noexcept(common_view{_VSTD::forward<_Range>(__range)}))
+      -> decltype(      common_view{_VSTD::forward<_Range>(__range)})
+      { return          common_view{_VSTD::forward<_Range>(__range)}; }
+  };
+}
+
+inline namespace __cpo {
+  inline constexpr auto common = __common::__fn{};
+}
+} // namespace views
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_COMMON_VIEW_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/concepts.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/concepts.h
new file mode 100644
index 00000000000..90028e34b7b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/concepts.h
@@ -0,0 +1,133 @@
+// -*- C++ -*-
+//===--------------------- __ranges/concepts.h ----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_CONCEPTS_H
+#define _LIBCPP___RANGES_CONCEPTS_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/iter_move.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/readable_traits.h>
+#include <__ranges/access.h>
+#include <__ranges/enable_borrowed_range.h>
+#include <__ranges/data.h>
+#include <__ranges/enable_view.h>
+#include <__ranges/size.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// clang-format off
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+  // [range.range]
+  template <class _Tp>
+  concept range = requires(_Tp& __t) {
+    ranges::begin(__t); // sometimes equality-preserving
+    ranges::end(__t);
+  };
+
+  template<class _Range>
+  concept borrowed_range = range<_Range> &&
+    (is_lvalue_reference_v<_Range> || enable_borrowed_range<remove_cvref_t<_Range>>);
+
+  // `iterator_t` defined in <__ranges/access.h>
+
+  template <range _Rp>
+  using sentinel_t = decltype(ranges::end(declval<_Rp&>()));
+
+  template <range _Rp>
+  using range_difference_t = iter_difference_t<iterator_t<_Rp>>;
+
+  template <range _Rp>
+  using range_value_t = iter_value_t<iterator_t<_Rp>>;
+
+  template <range _Rp>
+  using range_reference_t = iter_reference_t<iterator_t<_Rp>>;
+
+  template <range _Rp>
+  using range_rvalue_reference_t = iter_rvalue_reference_t<iterator_t<_Rp>>;
+
+  // [range.sized]
+  template <class _Tp>
+  concept sized_range = range<_Tp> && requires(_Tp& __t) { ranges::size(__t); };
+
+  template<sized_range _Rp>
+  using range_size_t = decltype(ranges::size(declval<_Rp&>()));
+
+  // `disable_sized_range` defined in `<__ranges/size.h>`
+
+  // [range.view], views
+
+  // `enable_view` defined in <__ranges/enable_view.h>
+  // `view_base` defined in <__ranges/enable_view.h>
+
+  template <class _Tp>
+  concept view =
+    range<_Tp> &&
+    movable<_Tp> &&
+    enable_view<_Tp>;
+
+  template<class _Range>
+  concept __simple_view =
+    view<_Range> && range<const _Range> &&
+    same_as<iterator_t<_Range>, iterator_t<const _Range>> &&
+    same_as<sentinel_t<_Range>, iterator_t<const _Range>>;
+
+  // [range.refinements], other range refinements
+  template <class _Rp, class _Tp>
+  concept output_range = range<_Rp> && output_iterator<iterator_t<_Rp>, _Tp>;
+
+  template <class _Tp>
+  concept input_range = range<_Tp> && input_iterator<iterator_t<_Tp>>;
+
+  template <class _Tp>
+  concept forward_range = input_range<_Tp> && forward_iterator<iterator_t<_Tp>>;
+
+  template <class _Tp>
+  concept bidirectional_range = forward_range<_Tp> && bidirectional_iterator<iterator_t<_Tp>>;
+
+  template <class _Tp>
+  concept random_access_range =
+      bidirectional_range<_Tp> && random_access_iterator<iterator_t<_Tp>>;
+
+  template<class _Tp>
+  concept contiguous_range =
+    random_access_range<_Tp> &&
+    contiguous_iterator<iterator_t<_Tp>> &&
+    requires(_Tp& __t) {
+      { ranges::data(__t) } -> same_as<add_pointer_t<range_reference_t<_Tp>>>;
+    };
+
+  template <class _Tp>
+  concept common_range = range<_Tp> && same_as<iterator_t<_Tp>, sentinel_t<_Tp>>;
+
+  template<class _Tp>
+  concept viewable_range =
+    range<_Tp> && (
+      (view<remove_cvref_t<_Tp>> && constructible_from<remove_cvref_t<_Tp>, _Tp>) ||
+      (!view<remove_cvref_t<_Tp>> && borrowed_range<_Tp>)
+    );
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+// clang-format on
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_CONCEPTS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/copyable_box.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/copyable_box.h
new file mode 100644
index 00000000000..4811690adae
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/copyable_box.h
@@ -0,0 +1,178 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___RANGES_COPYABLE_BOX_H
+#define _LIBCPP___RANGES_COPYABLE_BOX_H
+
+#include <__config>
+#include <__memory/addressof.h>
+#include <__memory/construct_at.h>
+#include <__utility/move.h>
+#include <concepts>
+#include <optional>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+// __copyable_box allows turning a type that is copy-constructible (but maybe not copy-assignable) into
+// a type that is both copy-constructible and copy-assignable. It does that by introducing an empty state
+// and basically doing destroy-then-copy-construct in the assignment operator. The empty state is necessary
+// to handle the case where the copy construction fails after destroying the object.
+//
+// In some cases, we can completely avoid the use of an empty state; we provide a specialization of
+// __copyable_box that does this, see below for the details.
+
+template<class _Tp>
+concept __copy_constructible_object = copy_constructible<_Tp> && is_object_v<_Tp>;
+
+namespace ranges {
+  // Primary template - uses std::optional and introduces an empty state in case assignment fails.
+  template<__copy_constructible_object _Tp>
+  class __copyable_box {
+    [[no_unique_address]] optional<_Tp> __val_;
+
+  public:
+    template<class ..._Args>
+      requires is_constructible_v<_Tp, _Args...>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit __copyable_box(in_place_t, _Args&& ...__args)
+      noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
+      : __val_(in_place, _VSTD::forward<_Args>(__args)...)
+    { }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __copyable_box() noexcept(is_nothrow_default_constructible_v<_Tp>)
+      requires default_initializable<_Tp>
+      : __val_(in_place)
+    { }
+
+    _LIBCPP_HIDE_FROM_ABI __copyable_box(__copyable_box const&) = default;
+    _LIBCPP_HIDE_FROM_ABI __copyable_box(__copyable_box&&) = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __copyable_box& operator=(__copyable_box const& __other)
+      noexcept(is_nothrow_copy_constructible_v<_Tp>)
+    {
+      if (this != _VSTD::addressof(__other)) {
+        if (__other.__has_value()) __val_.emplace(*__other);
+        else                       __val_.reset();
+      }
+      return *this;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    __copyable_box& operator=(__copyable_box&&) requires movable<_Tp> = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __copyable_box& operator=(__copyable_box&& __other)
+      noexcept(is_nothrow_move_constructible_v<_Tp>)
+    {
+      if (this != _VSTD::addressof(__other)) {
+        if (__other.__has_value()) __val_.emplace(_VSTD::move(*__other));
+        else                       __val_.reset();
+      }
+      return *this;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI constexpr _Tp const& operator*() const noexcept { return *__val_; }
+    _LIBCPP_HIDE_FROM_ABI constexpr _Tp& operator*() noexcept { return *__val_; }
+
+    _LIBCPP_HIDE_FROM_ABI constexpr const _Tp *operator->() const noexcept { return __val_.operator->(); }
+    _LIBCPP_HIDE_FROM_ABI constexpr _Tp *operator->() noexcept { return __val_.operator->(); }
+
+    _LIBCPP_HIDE_FROM_ABI constexpr bool __has_value() const noexcept { return __val_.has_value(); }
+  };
+
+  // This partial specialization implements an optimization for when we know we don't need to store
+  // an empty state to represent failure to perform an assignment. For copy-assignment, this happens:
+  //
+  // 1. If the type is copyable (which includes copy-assignment), we can use the type's own assignment operator
+  //    directly and avoid using std::optional.
+  // 2. If the type is not copyable, but it is nothrow-copy-constructible, then we can implement assignment as
+  //    destroy-and-then-construct and we know it will never fail, so we don't need an empty state.
+  //
+  // The exact same reasoning can be applied for move-assignment, with copyable replaced by movable and
+  // nothrow-copy-constructible replaced by nothrow-move-constructible. This specialization is enabled
+  // whenever we can apply any of these optimizations for both the copy assignment and the move assignment
+  // operator.
+  template<class _Tp>
+  concept __doesnt_need_empty_state_for_copy = copyable<_Tp> || is_nothrow_copy_constructible_v<_Tp>;
+
+  template<class _Tp>
+  concept __doesnt_need_empty_state_for_move = movable<_Tp> || is_nothrow_move_constructible_v<_Tp>;
+
+  template<__copy_constructible_object _Tp>
+    requires __doesnt_need_empty_state_for_copy<_Tp> && __doesnt_need_empty_state_for_move<_Tp>
+  class __copyable_box<_Tp> {
+    [[no_unique_address]] _Tp __val_;
+
+  public:
+    template<class ..._Args>
+      requires is_constructible_v<_Tp, _Args...>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit __copyable_box(in_place_t, _Args&& ...__args)
+      noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
+      : __val_(_VSTD::forward<_Args>(__args)...)
+    { }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __copyable_box() noexcept(is_nothrow_default_constructible_v<_Tp>)
+      requires default_initializable<_Tp>
+      : __val_()
+    { }
+
+    _LIBCPP_HIDE_FROM_ABI __copyable_box(__copyable_box const&) = default;
+    _LIBCPP_HIDE_FROM_ABI __copyable_box(__copyable_box&&) = default;
+
+    // Implementation of assignment operators in case we perform optimization (1)
+    _LIBCPP_HIDE_FROM_ABI __copyable_box& operator=(__copyable_box const&) requires copyable<_Tp> = default;
+    _LIBCPP_HIDE_FROM_ABI __copyable_box& operator=(__copyable_box&&) requires movable<_Tp> = default;
+
+    // Implementation of assignment operators in case we perform optimization (2)
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __copyable_box& operator=(__copyable_box const& __other) noexcept {
+      static_assert(is_nothrow_copy_constructible_v<_Tp>);
+      if (this != _VSTD::addressof(__other)) {
+        _VSTD::destroy_at(_VSTD::addressof(__val_));
+        _VSTD::construct_at(_VSTD::addressof(__val_), __other.__val_);
+      }
+      return *this;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __copyable_box& operator=(__copyable_box&& __other) noexcept {
+      static_assert(is_nothrow_move_constructible_v<_Tp>);
+      if (this != _VSTD::addressof(__other)) {
+        _VSTD::destroy_at(_VSTD::addressof(__val_));
+        _VSTD::construct_at(_VSTD::addressof(__val_), _VSTD::move(__other.__val_));
+      }
+      return *this;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI constexpr _Tp const& operator*() const noexcept { return __val_; }
+    _LIBCPP_HIDE_FROM_ABI constexpr _Tp& operator*() noexcept { return __val_; }
+
+    _LIBCPP_HIDE_FROM_ABI constexpr const _Tp *operator->() const noexcept { return _VSTD::addressof(__val_); }
+    _LIBCPP_HIDE_FROM_ABI constexpr _Tp *operator->() noexcept { return _VSTD::addressof(__val_); }
+
+    _LIBCPP_HIDE_FROM_ABI constexpr bool __has_value() const noexcept { return true; }
+  };
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_COPYABLE_BOX_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/counted.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/counted.h
new file mode 100644
index 00000000000..d292bcbb184
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/counted.h
@@ -0,0 +1,94 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_COUNTED_H
+#define _LIBCPP___RANGES_COUNTED_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/counted_iterator.h>
+#include <__iterator/default_sentinel.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
+#include <__memory/pointer_traits.h>
+#include <__ranges/concepts.h>
+#include <__ranges/subrange.h>
+#include <__utility/decay_copy.h>
+#include <__utility/declval.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <span>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges::views {
+
+namespace __counted {
+  template<class _From, class _To>
+  concept __explicitly_convertible = requires {
+    _To(_From{});
+  };
+
+  struct __fn {
+    template<class _Iter, class _Diff>
+      requires contiguous_iterator<decay_t<_Iter>> &&
+               __explicitly_convertible<_Diff, iter_difference_t<_Iter>>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Iter&& __it, _Diff __c) const
+      noexcept(noexcept(
+        span(_VSTD::to_address(__it), static_cast<iter_difference_t<_Iter>>(__c))
+      ))
+    {
+      return span(_VSTD::to_address(__it), static_cast<iter_difference_t<_Iter>>(__c));
+    }
+
+    template<class _Iter, class _Diff>
+      requires random_access_iterator<decay_t<_Iter>> &&
+               __explicitly_convertible<_Diff, iter_difference_t<_Iter>>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Iter&& __it, _Diff __c) const
+      noexcept(
+        noexcept(__it + static_cast<iter_difference_t<_Iter>>(__c)) &&
+        noexcept(ranges::subrange(_VSTD::forward<_Iter>(__it), _VSTD::__decay_copy(__it)))
+      )
+    {
+      auto __last = __it + static_cast<iter_difference_t<_Iter>>(__c);
+      return ranges::subrange(_VSTD::forward<_Iter>(__it), _VSTD::move(__last));
+    }
+
+    template<class _Iter, class _Diff>
+      requires __explicitly_convertible<_Diff, iter_difference_t<_Iter>>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Iter&& __it, _Diff __c) const
+      noexcept(noexcept(
+        ranges::subrange(counted_iterator(_VSTD::forward<_Iter>(__it), __c), default_sentinel)
+      ))
+    {
+      return ranges::subrange(counted_iterator(_VSTD::forward<_Iter>(__it), __c), default_sentinel);
+    }
+  };
+}
+
+inline namespace __cpo {
+  inline constexpr auto counted = __counted::__fn{};
+} // namespace __cpo
+
+} // namespace ranges::views
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_COUNTED_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/dangling.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/dangling.h
new file mode 100644
index 00000000000..45ff83b205e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/dangling.h
@@ -0,0 +1,42 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___RANGES_DANGLING_H
+#define _LIBCPP___RANGES_DANGLING_H
+
+#include <__config>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+struct dangling {
+  dangling() = default;
+  _LIBCPP_HIDE_FROM_ABI constexpr dangling(auto&&...) noexcept {}
+};
+
+template <range _Rp>
+using borrowed_iterator_t = _If<borrowed_range<_Rp>, iterator_t<_Rp>, dangling>;
+
+// borrowed_subrange_t defined in <__ranges/subrange.h>
+} // namespace ranges
+
+#endif // !_LIBCPP_HAS_NO_RANGES
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_DANGLING_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/data.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/data.h
new file mode 100644
index 00000000000..8060dd558a9
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/data.h
@@ -0,0 +1,81 @@
+// -*- C++ -*-
+//===------------------------ __ranges/data.h ------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_DATA_H
+#define _LIBCPP___RANGES_DATA_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/iterator_traits.h>
+#include <__memory/pointer_traits.h>
+#include <__ranges/access.h>
+#include <__utility/forward.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+// clang-format off
+namespace ranges {
+// [range.prim.data]
+namespace __data {
+  template <class _Tp>
+  concept __ptr_to_object = is_pointer_v<_Tp> && is_object_v<remove_pointer_t<_Tp>>;
+
+  template <class _Tp>
+  concept __member_data =
+    requires(_Tp&& __t) {
+      { _VSTD::forward<_Tp>(__t) } -> __can_borrow;
+      { __t.data() } -> __ptr_to_object;
+    };
+
+  template <class _Tp>
+  concept __ranges_begin_invocable =
+    !__member_data<_Tp> &&
+    requires(_Tp&& __t) {
+      { _VSTD::forward<_Tp>(__t) } -> __can_borrow;
+      { ranges::begin(_VSTD::forward<_Tp>(__t)) } -> contiguous_iterator;
+    };
+
+  struct __fn {
+    template <__member_data _Tp>
+      requires __can_borrow<_Tp>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __ptr_to_object auto operator()(_Tp&& __t) const
+        noexcept(noexcept(__t.data())) {
+      return __t.data();
+    }
+
+    template<__ranges_begin_invocable _Tp>
+      requires __can_borrow<_Tp>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __ptr_to_object auto operator()(_Tp&& __t) const
+        noexcept(noexcept(_VSTD::to_address(ranges::begin(_VSTD::forward<_Tp>(__t))))) {
+      return _VSTD::to_address(ranges::begin(_VSTD::forward<_Tp>(__t)));
+    }
+  };
+} // end namespace __data
+
+inline namespace __cpo {
+  inline constexpr auto data = __data::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+// clang-format off
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_DATA_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/drop_view.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/drop_view.h
new file mode 100644
index 00000000000..6adb09cf677
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/drop_view.h
@@ -0,0 +1,127 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_DROP_VIEW_H
+#define _LIBCPP___RANGES_DROP_VIEW_H
+
+#include <__config>
+#include <__debug>
+#include <__iterator/concepts.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
+#include <__ranges/access.h>
+#include <__ranges/all.h>
+#include <__ranges/concepts.h>
+#include <__ranges/enable_borrowed_range.h>
+#include <__ranges/non_propagating_cache.h>
+#include <__ranges/size.h>
+#include <__ranges/view_interface.h>
+#include <__utility/move.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+  template<view _View>
+  class drop_view
+    : public view_interface<drop_view<_View>>
+  {
+    // We cache begin() whenever ranges::next is not guaranteed O(1) to provide an
+    // amortized O(1) begin() method. If this is an input_range, then we cannot cache
+    // begin because begin is not equality preserving.
+    // Note: drop_view<input-range>::begin() is still trivially amortized O(1) because
+    // one can't call begin() on it more than once.
+    static constexpr bool _UseCache = forward_range<_View> && !(random_access_range<_View> && sized_range<_View>);
+    using _Cache = _If<_UseCache, __non_propagating_cache<iterator_t<_View>>, __empty_cache>;
+    [[no_unique_address]] _Cache __cached_begin_ = _Cache();
+    range_difference_t<_View> __count_ = 0;
+    _View __base_ = _View();
+
+public:
+    drop_view() requires default_initializable<_View> = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr drop_view(_View __base, range_difference_t<_View> __count)
+      : __count_(__count)
+      , __base_(_VSTD::move(__base))
+    {
+      _LIBCPP_ASSERT(__count_ >= 0, "count must be greater than or equal to zero.");
+    }
+
+    _LIBCPP_HIDE_FROM_ABI constexpr _View base() const& requires copy_constructible<_View> { return __base_; }
+    _LIBCPP_HIDE_FROM_ABI constexpr _View base() && { return _VSTD::move(__base_); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto begin()
+      requires (!(__simple_view<_View> &&
+                  random_access_range<const _View> && sized_range<const _View>))
+    {
+      if constexpr (_UseCache)
+        if (__cached_begin_.__has_value())
+          return *__cached_begin_;
+
+      auto __tmp = ranges::next(ranges::begin(__base_), __count_, ranges::end(__base_));
+      if constexpr (_UseCache)
+        __cached_begin_.__emplace(__tmp);
+      return __tmp;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto begin() const
+      requires random_access_range<const _View> && sized_range<const _View>
+    {
+      return ranges::next(ranges::begin(__base_), __count_, ranges::end(__base_));
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto end()
+      requires (!__simple_view<_View>)
+    { return ranges::end(__base_); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto end() const
+      requires range<const _View>
+    { return ranges::end(__base_); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    static constexpr auto __size(auto& __self) {
+      const auto __s = ranges::size(__self.__base_);
+      const auto __c = static_cast<decltype(__s)>(__self.__count_);
+      return __s < __c ? 0 : __s - __c;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto size()
+      requires sized_range<_View>
+    { return __size(*this); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto size() const
+      requires sized_range<const _View>
+    { return __size(*this); }
+  };
+
+  template<class _Range>
+  drop_view(_Range&&, range_difference_t<_Range>) -> drop_view<views::all_t<_Range>>;
+
+  template<class _Tp>
+  inline constexpr bool enable_borrowed_range<drop_view<_Tp>> = enable_borrowed_range<_Tp>;
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_DROP_VIEW_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/empty.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/empty.h
new file mode 100644
index 00000000000..fc6a938fd86
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/empty.h
@@ -0,0 +1,81 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_EMPTY_H
+#define _LIBCPP___RANGES_EMPTY_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__ranges/access.h>
+#include <__ranges/size.h>
+#include <__utility/forward.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+// clang-format off
+namespace ranges {
+// [range.prim.empty]
+namespace __empty {
+  template <class _Tp>
+  concept __member_empty = requires(_Tp&& __t) {
+    bool(_VSTD::forward<_Tp>(__t).empty());
+  };
+
+  template<class _Tp>
+  concept __can_invoke_size =
+    !__member_empty<_Tp> &&
+    requires(_Tp&& __t) { ranges::size(_VSTD::forward<_Tp>(__t)); };
+
+  template <class _Tp>
+  concept __can_compare_begin_end =
+    !__member_empty<_Tp> &&
+    !__can_invoke_size<_Tp> &&
+    requires(_Tp&& __t) {
+      bool(ranges::begin(__t) == ranges::end(__t));
+      { ranges::begin(__t) } -> forward_iterator;
+    };
+
+  struct __fn {
+    template <__member_empty _Tp>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool operator()(_Tp&& __t) const
+        noexcept(noexcept(bool(__t.empty()))) {
+      return __t.empty();
+    }
+
+    template <__can_invoke_size _Tp>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool operator()(_Tp&& __t) const
+        noexcept(noexcept(ranges::size(_VSTD::forward<_Tp>(__t)))) {
+      return ranges::size(_VSTD::forward<_Tp>(__t)) == 0;
+    }
+
+    template<__can_compare_begin_end _Tp>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool operator()(_Tp&& __t) const
+        noexcept(noexcept(bool(ranges::begin(__t) == ranges::end(__t)))) {
+      return ranges::begin(__t) == ranges::end(__t);
+    }
+  };
+}
+
+inline namespace __cpo {
+  inline constexpr auto empty = __empty::__fn{};
+} // namespace __cpo
+} // namespace ranges
+// clang-format off
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_EMPTY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/empty_view.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/empty_view.h
new file mode 100644
index 00000000000..4a98a6f324e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/empty_view.h
@@ -0,0 +1,41 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_EMPTY_VIEW_H
+#define _LIBCPP___RANGES_EMPTY_VIEW_H
+
+#include <__config>
+#include <__ranges/view_interface.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+  template<class _Tp>
+    requires is_object_v<_Tp>
+  class empty_view : public view_interface<empty_view<_Tp>> {
+  public:
+    _LIBCPP_HIDE_FROM_ABI static constexpr _Tp* begin() noexcept { return nullptr; }
+    _LIBCPP_HIDE_FROM_ABI static constexpr _Tp* end() noexcept { return nullptr; }
+    _LIBCPP_HIDE_FROM_ABI static constexpr _Tp* data() noexcept { return nullptr; }
+    _LIBCPP_HIDE_FROM_ABI static constexpr size_t size() noexcept { return 0; }
+    _LIBCPP_HIDE_FROM_ABI static constexpr bool empty() noexcept { return true; }
+  };
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_EMPTY_VIEW_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/enable_borrowed_range.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/enable_borrowed_range.h
new file mode 100644
index 00000000000..220db8bbf5c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/enable_borrowed_range.h
@@ -0,0 +1,41 @@
+// -*- C++ -*-
+//===------------------ __ranges/enable_borrowed_range.h ------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___RANGES_ENABLE_BORROWED_RANGE_H
+#define _LIBCPP___RANGES_ENABLE_BORROWED_RANGE_H
+
+// These customization variables are used in <span> and <string_view>. The
+// separate header is used to avoid including the entire <ranges> header in
+// <span> and <string_view>.
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges
+{
+
+// [range.range], ranges
+
+template <class>
+inline constexpr bool enable_borrowed_range = false;
+
+} // namespace ranges
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_ENABLE_BORROWED_RANGE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/enable_view.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/enable_view.h
new file mode 100644
index 00000000000..a09de11da81
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/enable_view.h
@@ -0,0 +1,37 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___RANGES_ENABLE_VIEW_H
+#define _LIBCPP___RANGES_ENABLE_VIEW_H
+
+#include <__config>
+#include <concepts>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+
+struct view_base { };
+
+template <class _Tp>
+inline constexpr bool enable_view = derived_from<_Tp, view_base>;
+
+} // end namespace ranges
+
+#endif // !_LIBCPP_HAS_NO_RANGES
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_ENABLE_VIEW_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/iota_view.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/iota_view.h
new file mode 100644
index 00000000000..da712b8e6f4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/iota_view.h
@@ -0,0 +1,408 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_IOTA_VIEW_H
+#define _LIBCPP___RANGES_IOTA_VIEW_H
+
+#include <__compare/three_way_comparable.h>
+#include <__concepts/arithmetic.h>
+#include <__concepts/constructible.h>
+#include <__concepts/convertible_to.h>
+#include <__concepts/copyable.h>
+#include <__concepts/equality_comparable.h>
+#include <__concepts/invocable.h>
+#include <__concepts/same_as.h>
+#include <__concepts/semiregular.h>
+#include <__concepts/totally_ordered.h>
+#include <__config>
+#include <__debug>
+#include <__functional/ranges_operations.h>
+#include <__iterator/concepts.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/unreachable_sentinel.h>
+#include <__ranges/copyable_box.h>
+#include <__ranges/enable_borrowed_range.h>
+#include <__ranges/view_interface.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+  template<class _Int>
+  struct __get_wider_signed {
+    static auto __call() {
+           if constexpr (sizeof(_Int) < sizeof(short)) return type_identity<short>{};
+      else if constexpr (sizeof(_Int) < sizeof(int))   return type_identity<int>{};
+      else if constexpr (sizeof(_Int) < sizeof(long))  return type_identity<long>{};
+      else                                             return type_identity<long long>{};
+
+      static_assert(sizeof(_Int) <= sizeof(long long),
+        "Found integer-like type that is bigger than largest integer like type.");
+    }
+
+    using type = typename decltype(__call())::type;
+  };
+
+  template<class _Start>
+  using _IotaDiffT = typename _If<
+      (!integral<_Start> || sizeof(iter_difference_t<_Start>) > sizeof(_Start)),
+      type_identity<iter_difference_t<_Start>>,
+      __get_wider_signed<_Start>
+    >::type;
+
+  template<class _Iter>
+  concept __decrementable = incrementable<_Iter> && requires(_Iter __i) {
+    { --__i } -> same_as<_Iter&>;
+    { __i-- } -> same_as<_Iter>;
+  };
+
+  template<class _Iter>
+  concept __advanceable =
+    __decrementable<_Iter> && totally_ordered<_Iter> &&
+    requires(_Iter __i, const _Iter __j, const _IotaDiffT<_Iter> __n) {
+      { __i += __n } -> same_as<_Iter&>;
+      { __i -= __n } -> same_as<_Iter&>;
+      _Iter(__j + __n);
+      _Iter(__n + __j);
+      _Iter(__j - __n);
+      { __j - __j } -> convertible_to<_IotaDiffT<_Iter>>;
+    };
+
+  template<class>
+  struct __iota_iterator_category {};
+
+  template<incrementable _Tp>
+  struct __iota_iterator_category<_Tp> {
+    using iterator_category = input_iterator_tag;
+  };
+
+  template<weakly_incrementable _Start, semiregular _Bound = unreachable_sentinel_t>
+    requires __weakly_equality_comparable_with<_Start, _Bound> && copyable<_Start>
+  class iota_view : public view_interface<iota_view<_Start, _Bound>> {
+    struct __iterator : public __iota_iterator_category<_Start> {
+      friend class iota_view;
+
+      using iterator_concept =
+        _If<__advanceable<_Start>,   random_access_iterator_tag,
+        _If<__decrementable<_Start>, bidirectional_iterator_tag,
+        _If<incrementable<_Start>,   forward_iterator_tag,
+        /*Else*/                     input_iterator_tag>>>;
+
+      using value_type = _Start;
+      using difference_type = _IotaDiffT<_Start>;
+
+      _Start __value_ = _Start();
+
+      _LIBCPP_HIDE_FROM_ABI
+      __iterator() requires default_initializable<_Start> = default;
+
+      _LIBCPP_HIDE_FROM_ABI
+      constexpr explicit __iterator(_Start __value) : __value_(_VSTD::move(__value)) {}
+
+      _LIBCPP_HIDE_FROM_ABI
+      constexpr _Start operator*() const noexcept(is_nothrow_copy_constructible_v<_Start>) {
+        return __value_;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      constexpr __iterator& operator++() {
+        ++__value_;
+        return *this;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      constexpr void operator++(int) { ++*this; }
+
+      _LIBCPP_HIDE_FROM_ABI
+      constexpr __iterator operator++(int) requires incrementable<_Start> {
+        auto __tmp = *this;
+        ++*this;
+        return __tmp;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      constexpr __iterator& operator--() requires __decrementable<_Start> {
+        --__value_;
+        return *this;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      constexpr __iterator  operator--(int) requires __decrementable<_Start> {
+        auto __tmp = *this;
+        --*this;
+        return __tmp;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      constexpr __iterator& operator+=(difference_type __n)
+        requires __advanceable<_Start>
+      {
+        if constexpr (__integer_like<_Start> && !__signed_integer_like<_Start>) {
+          if (__n >= difference_type(0)) {
+            __value_ += static_cast<_Start>(__n);
+          } else {
+            __value_ -= static_cast<_Start>(-__n);
+          }
+        } else {
+          __value_ += __n;
+        }
+        return *this;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      constexpr __iterator& operator-=(difference_type __n)
+        requires __advanceable<_Start>
+      {
+        if constexpr (__integer_like<_Start> && !__signed_integer_like<_Start>) {
+          if (__n >= difference_type(0)) {
+            __value_ -= static_cast<_Start>(__n);
+          } else {
+            __value_ += static_cast<_Start>(-__n);
+          }
+        } else {
+          __value_ -= __n;
+        }
+        return *this;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      constexpr _Start operator[](difference_type __n) const
+        requires __advanceable<_Start>
+      {
+        return _Start(__value_ + __n);
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      friend constexpr bool operator==(const __iterator& __x, const __iterator& __y)
+        requires equality_comparable<_Start>
+      {
+        return __x.__value_ == __y.__value_;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      friend constexpr bool operator<(const __iterator& __x, const __iterator& __y)
+        requires totally_ordered<_Start>
+      {
+        return __x.__value_ < __y.__value_;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      friend constexpr bool operator>(const __iterator& __x, const __iterator& __y)
+        requires totally_ordered<_Start>
+      {
+        return __y < __x;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      friend constexpr bool operator<=(const __iterator& __x, const __iterator& __y)
+        requires totally_ordered<_Start>
+      {
+        return !(__y < __x);
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      friend constexpr bool operator>=(const __iterator& __x, const __iterator& __y)
+        requires totally_ordered<_Start>
+      {
+        return !(__x < __y);
+      }
+
+      friend constexpr auto operator<=>(const __iterator& __x, const __iterator& __y)
+        requires totally_ordered<_Start> && three_way_comparable<_Start>
+      {
+        return __x.__value_ <=> __y.__value_;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      friend constexpr __iterator operator+(__iterator __i, difference_type __n)
+        requires __advanceable<_Start>
+      {
+        __i += __n;
+        return __i;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      friend constexpr __iterator operator+(difference_type __n, __iterator __i)
+        requires __advanceable<_Start>
+      {
+        return __i + __n;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      friend constexpr __iterator operator-(__iterator __i, difference_type __n)
+        requires __advanceable<_Start>
+      {
+        __i -= __n;
+        return __i;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      friend constexpr difference_type operator-(const __iterator& __x, const __iterator& __y)
+        requires __advanceable<_Start>
+      {
+        if constexpr (__integer_like<_Start>) {
+          if constexpr (__signed_integer_like<_Start>) {
+            return difference_type(difference_type(__x.__value_) - difference_type(__y.__value_));
+          }
+          if (__y.__value_ > __x.__value_) {
+            return difference_type(-difference_type(__y.__value_ - __x.__value_));
+          }
+          return difference_type(__x.__value_ - __y.__value_);
+        }
+        return __x.__value_ - __y.__value_;
+      }
+    };
+
+    struct __sentinel {
+      friend class iota_view;
+
+    private:
+      _Bound __bound_ = _Bound();
+
+    public:
+      _LIBCPP_HIDE_FROM_ABI
+      __sentinel() = default;
+      constexpr explicit __sentinel(_Bound __bound) : __bound_(_VSTD::move(__bound)) {}
+
+      _LIBCPP_HIDE_FROM_ABI
+      friend constexpr bool operator==(const __iterator& __x, const __sentinel& __y) {
+        return __x.__value_ == __y.__bound_;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      friend constexpr iter_difference_t<_Start> operator-(const __iterator& __x, const __sentinel& __y)
+        requires sized_sentinel_for<_Bound, _Start>
+      {
+        return __x.__value_ - __y.__bound_;
+      }
+
+      _LIBCPP_HIDE_FROM_ABI
+      friend constexpr iter_difference_t<_Start> operator-(const __sentinel& __x, const __iterator& __y)
+        requires sized_sentinel_for<_Bound, _Start>
+      {
+        return -(__y - __x);
+      }
+    };
+
+    _Start __value_ = _Start();
+    _Bound __bound_ = _Bound();
+
+  public:
+    _LIBCPP_HIDE_FROM_ABI
+    iota_view() requires default_initializable<_Start> = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit iota_view(_Start __value) : __value_(_VSTD::move(__value)) { }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr iota_view(type_identity_t<_Start> __value, type_identity_t<_Bound> __bound)
+      : __value_(_VSTD::move(__value)), __bound_(_VSTD::move(__bound)) {
+      // Validate the precondition if possible.
+      if constexpr (totally_ordered_with<_Start, _Bound>) {
+        _LIBCPP_ASSERT(ranges::less_equal()(__value_, __bound_),
+                       "Precondition violated: value is greater than bound.");
+      }
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr iota_view(__iterator __first, __iterator __last)
+      requires same_as<_Start, _Bound>
+      : iota_view(_VSTD::move(__first.__value_), _VSTD::move(__last.__value_)) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr iota_view(__iterator __first, _Bound __last)
+      requires same_as<_Bound, unreachable_sentinel_t>
+      : iota_view(_VSTD::move(__first.__value_), _VSTD::move(__last)) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr iota_view(__iterator __first, __sentinel __last)
+      requires (!same_as<_Start, _Bound> && !same_as<_Start, unreachable_sentinel_t>)
+      : iota_view(_VSTD::move(__first.__value_), _VSTD::move(__last.__bound_)) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __iterator begin() const { return __iterator{__value_}; }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto end() const {
+      if constexpr (same_as<_Bound, unreachable_sentinel_t>)
+        return unreachable_sentinel;
+      else
+        return __sentinel{__bound_};
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __iterator end() const requires same_as<_Start, _Bound> {
+      return __iterator{__bound_};
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto size() const
+      requires (same_as<_Start, _Bound> && __advanceable<_Start>) ||
+               (integral<_Start> && integral<_Bound>) ||
+               sized_sentinel_for<_Bound, _Start>
+    {
+      if constexpr (__integer_like<_Start> && __integer_like<_Bound>) {
+        if (__value_ < 0) {
+          if (__bound_ < 0) {
+            return _VSTD::__to_unsigned_like(-__value_) - _VSTD::__to_unsigned_like(-__bound_);
+          }
+          return _VSTD::__to_unsigned_like(__bound_) + _VSTD::__to_unsigned_like(-__value_);
+        }
+        return _VSTD::__to_unsigned_like(__bound_) - _VSTD::__to_unsigned_like(__value_);
+      }
+      return _VSTD::__to_unsigned_like(__bound_ - __value_);
+    }
+  };
+
+  template<class _Start, class _Bound>
+    requires (!__integer_like<_Start> || !__integer_like<_Bound> ||
+              (__signed_integer_like<_Start> == __signed_integer_like<_Bound>))
+  iota_view(_Start, _Bound) -> iota_view<_Start, _Bound>;
+
+  template<class _Start, class _Bound>
+  inline constexpr bool enable_borrowed_range<iota_view<_Start, _Bound>> = true;
+
+namespace views {
+namespace __iota {
+  struct __fn {
+    template<class _Start>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Start&& __start) const
+      noexcept(noexcept(ranges::iota_view(_VSTD::forward<_Start>(__start))))
+      -> decltype(      ranges::iota_view(_VSTD::forward<_Start>(__start)))
+      { return          ranges::iota_view(_VSTD::forward<_Start>(__start)); }
+
+    template<class _Start, class _Bound>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Start&& __start, _Bound&& __bound) const
+      noexcept(noexcept(ranges::iota_view(_VSTD::forward<_Start>(__start), _VSTD::forward<_Bound>(__bound))))
+      -> decltype(      ranges::iota_view(_VSTD::forward<_Start>(__start), _VSTD::forward<_Bound>(__bound)))
+      { return          ranges::iota_view(_VSTD::forward<_Start>(__start), _VSTD::forward<_Bound>(__bound)); }
+  };
+} // namespace __iota
+
+inline namespace __cpo {
+  inline constexpr auto iota = __iota::__fn{};
+}
+} // namespace views
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_IOTA_VIEW_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/join_view.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/join_view.h
new file mode 100644
index 00000000000..9aa69da76cf
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/join_view.h
@@ -0,0 +1,350 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_JOIN_VIEW_H
+#define _LIBCPP___RANGES_JOIN_VIEW_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/iterator_traits.h>
+#include <__ranges/access.h>
+#include <__ranges/all.h>
+#include <__ranges/concepts.h>
+#include <__ranges/non_propagating_cache.h>
+#include <__ranges/ref_view.h>
+#include <__ranges/subrange.h>
+#include <__ranges/view_interface.h>
+#include <__utility/declval.h>
+#include <__utility/forward.h>
+#include <optional>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+  template<class>
+  struct __join_view_iterator_category {};
+
+  template<class _View>
+    requires is_reference_v<range_reference_t<_View>> &&
+             forward_range<_View> &&
+             forward_range<range_reference_t<_View>>
+  struct __join_view_iterator_category<_View> {
+    using _OuterC = typename iterator_traits<iterator_t<_View>>::iterator_category;
+    using _InnerC = typename iterator_traits<iterator_t<range_reference_t<_View>>>::iterator_category;
+
+    using iterator_category = _If<
+      derived_from<_OuterC, bidirectional_iterator_tag> && derived_from<_InnerC, bidirectional_iterator_tag>,
+      bidirectional_iterator_tag,
+      _If<
+        derived_from<_OuterC, forward_iterator_tag> && derived_from<_InnerC, forward_iterator_tag>,
+        forward_iterator_tag,
+        input_iterator_tag
+      >
+    >;
+  };
+
+  template<input_range _View>
+    requires view<_View> && input_range<range_reference_t<_View>>
+  class join_view
+    : public view_interface<join_view<_View>> {
+  private:
+    using _InnerRange = range_reference_t<_View>;
+
+    template<bool> struct __iterator;
+    template<bool> struct __sentinel;
+
+    static constexpr bool _UseCache = !is_reference_v<_InnerRange>;
+    using _Cache = _If<_UseCache, __non_propagating_cache<remove_cvref_t<_InnerRange>>, __empty_cache>;
+    [[no_unique_address]] _Cache __cache_;
+    _View __base_ = _View(); // TODO: [[no_unique_address]] makes clang crash! File a bug :)
+
+  public:
+    _LIBCPP_HIDE_FROM_ABI
+    join_view() requires default_initializable<_View> = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit join_view(_View __base)
+      : __base_(_VSTD::move(__base)) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _View base() const& requires copy_constructible<_View> { return __base_; }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _View base() && { return _VSTD::move(__base_); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto begin() {
+      constexpr bool __use_const = __simple_view<_View> &&
+                                   is_reference_v<range_reference_t<_View>>;
+      return __iterator<__use_const>{*this, ranges::begin(__base_)};
+    }
+
+    template<class _V2 = _View>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto begin() const
+      requires input_range<const _V2> &&
+               is_reference_v<range_reference_t<const _V2>>
+    {
+      return __iterator<true>{*this, ranges::begin(__base_)};
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto end() {
+      if constexpr (forward_range<_View> &&
+                    is_reference_v<_InnerRange> &&
+                    forward_range<_InnerRange> &&
+                    common_range<_View> &&
+                    common_range<_InnerRange>)
+        return __iterator<__simple_view<_View>>{*this, ranges::end(__base_)};
+      else
+        return __sentinel<__simple_view<_View>>{*this};
+    }
+
+    template<class _V2 = _View>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto end() const
+      requires input_range<const _V2> &&
+               is_reference_v<range_reference_t<const _V2>>
+    {
+      using _ConstInnerRange = range_reference_t<const _View>;
+      if constexpr (forward_range<const _View> &&
+                    is_reference_v<_ConstInnerRange> &&
+                    forward_range<_ConstInnerRange> &&
+                    common_range<const _View> &&
+                    common_range<_ConstInnerRange>) {
+        return __iterator<true>{*this, ranges::end(__base_)};
+      } else {
+        return __sentinel<true>{*this};
+      }
+    }
+  };
+
+  template<input_range _View>
+    requires view<_View> && input_range<range_reference_t<_View>>
+  template<bool _Const> struct join_view<_View>::__sentinel {
+    template<bool> friend struct __sentinel;
+
+  private:
+    using _Parent = __maybe_const<_Const, join_view>;
+    using _Base = __maybe_const<_Const, _View>;
+    sentinel_t<_Base> __end_ = sentinel_t<_Base>();
+
+  public:
+    _LIBCPP_HIDE_FROM_ABI
+    __sentinel() = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit __sentinel(_Parent& __parent)
+      : __end_(ranges::end(__parent.__base_)) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __sentinel(__sentinel<!_Const> __s)
+      requires _Const && convertible_to<sentinel_t<_View>, sentinel_t<_Base>>
+      : __end_(_VSTD::move(__s.__end_)) {}
+
+    template<bool _OtherConst>
+      requires sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
+    _LIBCPP_HIDE_FROM_ABI
+    friend constexpr bool operator==(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
+      return __x.__outer_ == __y.__end_;
+    }
+  };
+
+  template<input_range _View>
+    requires view<_View> && input_range<range_reference_t<_View>>
+  template<bool _Const> struct join_view<_View>::__iterator
+    : public __join_view_iterator_category<__maybe_const<_Const, _View>> {
+
+    template<bool> friend struct __iterator;
+
+  private:
+    using _Parent = __maybe_const<_Const, join_view>;
+    using _Base = __maybe_const<_Const, _View>;
+    using _Outer = iterator_t<_Base>;
+    using _Inner = iterator_t<range_reference_t<_Base>>;
+
+    static constexpr bool __ref_is_glvalue = is_reference_v<range_reference_t<_Base>>;
+
+  public:
+    _Outer __outer_ = _Outer();
+
+  private:
+    optional<_Inner> __inner_;
+    _Parent *__parent_ = nullptr;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void __satisfy() {
+      for (; __outer_ != ranges::end(__parent_->__base_); ++__outer_) {
+        auto&& __inner = [&]() -> auto&& {
+          if constexpr (__ref_is_glvalue)
+            return *__outer_;
+          else
+            return __parent_->__cache_.__emplace_from([&]() -> decltype(auto) { return *__outer_; });
+        }();
+        __inner_ = ranges::begin(__inner);
+        if (*__inner_ != ranges::end(__inner))
+          return;
+      }
+
+      if constexpr (__ref_is_glvalue)
+        __inner_.reset();
+    }
+
+  public:
+    using iterator_concept = _If<
+      __ref_is_glvalue && bidirectional_range<_Base> && bidirectional_range<range_reference_t<_Base>>,
+      bidirectional_iterator_tag,
+      _If<
+        __ref_is_glvalue && forward_range<_Base> && forward_range<range_reference_t<_Base>>,
+        forward_iterator_tag,
+        input_iterator_tag
+      >
+    >;
+
+    using value_type = range_value_t<range_reference_t<_Base>>;
+
+    using difference_type = common_type_t<
+      range_difference_t<_Base>, range_difference_t<range_reference_t<_Base>>>;
+
+    _LIBCPP_HIDE_FROM_ABI
+    __iterator() requires default_initializable<_Outer> = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __iterator(_Parent& __parent, _Outer __outer)
+      : __outer_(_VSTD::move(__outer))
+      , __parent_(_VSTD::addressof(__parent)) {
+      __satisfy();
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __iterator(__iterator<!_Const> __i)
+      requires _Const &&
+               convertible_to<iterator_t<_View>, _Outer> &&
+               convertible_to<iterator_t<_InnerRange>, _Inner>
+      : __outer_(_VSTD::move(__i.__outer_))
+      , __inner_(_VSTD::move(__i.__inner_))
+      , __parent_(__i.__parent_) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr decltype(auto) operator*() const {
+      return **__inner_;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _Inner operator->() const
+      requires __has_arrow<_Inner> && copyable<_Inner>
+    {
+      return *__inner_;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __iterator& operator++() {
+      auto&& __inner = [&]() -> auto&& {
+        if constexpr (__ref_is_glvalue)
+          return *__outer_;
+        else
+          return *__parent_->__cache_;
+      }();
+      if (++*__inner_ == ranges::end(__inner)) {
+        ++__outer_;
+        __satisfy();
+      }
+      return *this;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr void operator++(int) {
+      ++*this;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __iterator operator++(int)
+      requires __ref_is_glvalue &&
+               forward_range<_Base> &&
+               forward_range<range_reference_t<_Base>>
+    {
+      auto __tmp = *this;
+      ++*this;
+      return __tmp;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __iterator& operator--()
+      requires __ref_is_glvalue &&
+               bidirectional_range<_Base> &&
+               bidirectional_range<range_reference_t<_Base>> &&
+               common_range<range_reference_t<_Base>>
+    {
+      if (__outer_ == ranges::end(__parent_->__base_))
+        __inner_ = ranges::end(*--__outer_);
+
+      // Skip empty inner ranges when going backwards.
+      while (*__inner_ == ranges::begin(*__outer_)) {
+        __inner_ = ranges::end(*--__outer_);
+      }
+
+      --*__inner_;
+      return *this;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __iterator operator--(int)
+      requires __ref_is_glvalue &&
+               bidirectional_range<_Base> &&
+               bidirectional_range<range_reference_t<_Base>> &&
+               common_range<range_reference_t<_Base>>
+    {
+      auto __tmp = *this;
+      --*this;
+      return __tmp;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    friend constexpr bool operator==(const __iterator& __x, const __iterator& __y)
+      requires __ref_is_glvalue &&
+               equality_comparable<iterator_t<_Base>> &&
+               equality_comparable<iterator_t<range_reference_t<_Base>>>
+    {
+      return __x.__outer_ == __y.__outer_ && __x.__inner_ == __y.__inner_;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    friend constexpr decltype(auto) iter_move(const __iterator& __i)
+      noexcept(noexcept(ranges::iter_move(*__i.__inner_)))
+    {
+      return ranges::iter_move(*__i.__inner_);
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    friend constexpr void iter_swap(const __iterator& __x, const __iterator& __y)
+      noexcept(noexcept(ranges::iter_swap(*__x.__inner_, *__y.__inner_)))
+      requires indirectly_swappable<_Inner>
+    {
+      return ranges::iter_swap(*__x.__inner_, *__y.__inner_);
+    }
+  };
+
+  template<class _Range>
+  explicit join_view(_Range&&) -> join_view<views::all_t<_Range>>;
+
+} // namespace ranges
+
+#undef _CONSTEXPR_TERNARY
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_JOIN_VIEW_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/non_propagating_cache.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/non_propagating_cache.h
new file mode 100644
index 00000000000..456e08d8c97
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/non_propagating_cache.h
@@ -0,0 +1,114 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_NON_PROPAGATING_CACHE_H
+#define _LIBCPP___RANGES_NON_PROPAGATING_CACHE_H
+
+#include <__config>
+#include <__iterator/concepts.h>        // indirectly_readable
+#include <__iterator/iterator_traits.h> // iter_reference_t
+#include <__memory/addressof.h>
+#include <__utility/forward.h>
+#include <concepts>                     // constructible_from
+#include <optional>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+  // __non_propagating_cache is a helper type that allows storing an optional value in it,
+  // but which does not copy the source's value when it is copy constructed/assigned to,
+  // and which resets the source's value when it is moved-from.
+  //
+  // This type is used as an implementation detail of some views that need to cache the
+  // result of `begin()` in order to provide an amortized O(1) begin() method. Typically,
+  // we don't want to propagate the value of the cache upon copy because the cached iterator
+  // may refer to internal details of the source view.
+  template<class _Tp>
+    requires is_object_v<_Tp>
+  class _LIBCPP_TEMPLATE_VIS __non_propagating_cache {
+    struct __from_tag { };
+    struct __forward_tag { };
+
+    // This helper class is needed to perform copy and move elision when
+    // constructing the contained type from an iterator.
+    struct __wrapper {
+      template<class ..._Args>
+      constexpr explicit __wrapper(__forward_tag, _Args&& ...__args) : __t_(_VSTD::forward<_Args>(__args)...) { }
+      template<class _Fn>
+      constexpr explicit __wrapper(__from_tag, _Fn const& __f) : __t_(__f()) { }
+      _Tp __t_;
+    };
+
+    optional<__wrapper> __value_ = nullopt;
+
+  public:
+    _LIBCPP_HIDE_FROM_ABI __non_propagating_cache() = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __non_propagating_cache(__non_propagating_cache const&) noexcept
+      : __value_(nullopt)
+    { }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __non_propagating_cache(__non_propagating_cache&& __other) noexcept
+      : __value_(nullopt)
+    {
+      __other.__value_.reset();
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __non_propagating_cache& operator=(__non_propagating_cache const& __other) noexcept {
+      if (this != _VSTD::addressof(__other)) {
+        __value_.reset();
+      }
+      return *this;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __non_propagating_cache& operator=(__non_propagating_cache&& __other) noexcept {
+      __value_.reset();
+      __other.__value_.reset();
+      return *this;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _Tp& operator*() { return __value_->__t_; }
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _Tp const& operator*() const { return __value_->__t_; }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr bool __has_value() const { return __value_.has_value(); }
+
+    template<class _Fn>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _Tp& __emplace_from(_Fn const& __f) {
+      return __value_.emplace(__from_tag{}, __f).__t_;
+    }
+
+    template<class ..._Args>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _Tp& __emplace(_Args&& ...__args) {
+      return __value_.emplace(__forward_tag{}, _VSTD::forward<_Args>(__args)...).__t_;
+    }
+  };
+
+  struct __empty_cache { };
+} // namespace ranges
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_NON_PROPAGATING_CACHE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/range_adaptor.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/range_adaptor.h
new file mode 100644
index 00000000000..74aea3187e8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/range_adaptor.h
@@ -0,0 +1,73 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___RANGES_RANGE_ADAPTOR_H
+#define _LIBCPP___RANGES_RANGE_ADAPTOR_H
+
+#include <__config>
+#include <__functional/compose.h>
+#include <__functional/invoke.h>
+#include <__ranges/concepts.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+// CRTP base that one can derive from in order to be considered a range adaptor closure
+// by the library. When deriving from this class, a pipe operator will be provided to
+// make the following hold:
+// - `x | f` is equivalent to `f(x)`
+// - `f1 | f2` is an adaptor closure `g` such that `g(x)` is equivalent to `f2(f1(x))`
+template <class _Tp>
+struct __range_adaptor_closure;
+
+// Type that wraps an arbitrary function object and makes it into a range adaptor closure,
+// i.e. something that can be called via the `x | f` notation.
+template <class _Fn>
+struct __range_adaptor_closure_t : _Fn, __range_adaptor_closure<__range_adaptor_closure_t<_Fn>> {
+    constexpr explicit __range_adaptor_closure_t(_Fn&& __f) : _Fn(_VSTD::move(__f)) { }
+};
+
+template <class _Tp>
+concept _RangeAdaptorClosure = derived_from<remove_cvref_t<_Tp>, __range_adaptor_closure<remove_cvref_t<_Tp>>>;
+
+template <class _Tp>
+struct __range_adaptor_closure {
+    template <ranges::viewable_range _View, _RangeAdaptorClosure _Closure>
+        requires same_as<_Tp, remove_cvref_t<_Closure>> &&
+                 invocable<_Closure, _View>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
+    friend constexpr decltype(auto) operator|(_View&& __view, _Closure&& __closure)
+        noexcept(is_nothrow_invocable_v<_Closure, _View>)
+    { return _VSTD::invoke(_VSTD::forward<_Closure>(__closure), _VSTD::forward<_View>(__view)); }
+
+    template <_RangeAdaptorClosure _Closure, _RangeAdaptorClosure _OtherClosure>
+        requires same_as<_Tp, remove_cvref_t<_Closure>> &&
+                 constructible_from<decay_t<_Closure>, _Closure> &&
+                 constructible_from<decay_t<_OtherClosure>, _OtherClosure>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
+    friend constexpr auto operator|(_Closure&& __c1, _OtherClosure&& __c2)
+        noexcept(is_nothrow_constructible_v<decay_t<_Closure>, _Closure> &&
+                 is_nothrow_constructible_v<decay_t<_OtherClosure>, _OtherClosure>)
+    { return __range_adaptor_closure_t(_VSTD::__compose(_VSTD::forward<_OtherClosure>(__c2), _VSTD::forward<_Closure>(__c1))); }
+};
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_RANGE_ADAPTOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/ref_view.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/ref_view.h
new file mode 100644
index 00000000000..7567ac48f25
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/ref_view.h
@@ -0,0 +1,83 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_REF_VIEW_H
+#define _LIBCPP___RANGES_REF_VIEW_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
+#include <__memory/addressof.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/data.h>
+#include <__ranges/empty.h>
+#include <__ranges/size.h>
+#include <__ranges/view_interface.h>
+#include <__utility/forward.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+  template<range _Range>
+    requires is_object_v<_Range>
+  class ref_view : public view_interface<ref_view<_Range>> {
+    _Range *__range_;
+
+    static void __fun(_Range&);
+    static void __fun(_Range&&) = delete;
+
+public:
+    template<class _Tp>
+      requires __different_from<_Tp, ref_view> &&
+        convertible_to<_Tp, _Range&> && requires { __fun(declval<_Tp>()); }
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr ref_view(_Tp&& __t)
+      : __range_(_VSTD::addressof(static_cast<_Range&>(_VSTD::forward<_Tp>(__t))))
+    {}
+
+    _LIBCPP_HIDE_FROM_ABI constexpr _Range& base() const { return *__range_; }
+
+    _LIBCPP_HIDE_FROM_ABI constexpr iterator_t<_Range> begin() const { return ranges::begin(*__range_); }
+    _LIBCPP_HIDE_FROM_ABI constexpr sentinel_t<_Range> end() const { return ranges::end(*__range_); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr bool empty() const
+      requires requires { ranges::empty(*__range_); }
+    { return ranges::empty(*__range_); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto size() const
+      requires sized_range<_Range>
+    { return ranges::size(*__range_); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto data() const
+      requires contiguous_range<_Range>
+    { return ranges::data(*__range_); }
+  };
+
+  template<class _Range>
+  ref_view(_Range&) -> ref_view<_Range>;
+
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_REF_VIEW_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/reverse_view.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/reverse_view.h
new file mode 100644
index 00000000000..ad88dc71380
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/reverse_view.h
@@ -0,0 +1,113 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_REVERSE_VIEW_H
+#define _LIBCPP___RANGES_REVERSE_VIEW_H
+
+#include <__concepts/constructible.h>
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/next.h>
+#include <__iterator/reverse_iterator.h>
+#include <__ranges/access.h>
+#include <__ranges/all.h>
+#include <__ranges/concepts.h>
+#include <__ranges/enable_borrowed_range.h>
+#include <__ranges/non_propagating_cache.h>
+#include <__ranges/size.h>
+#include <__ranges/view_interface.h>
+#include <__utility/move.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+  template<view _View>
+    requires bidirectional_range<_View>
+  class reverse_view : public view_interface<reverse_view<_View>> {
+    // We cache begin() whenever ranges::next is not guaranteed O(1) to provide an
+    // amortized O(1) begin() method.
+    static constexpr bool _UseCache = !random_access_range<_View> && !common_range<_View>;
+    using _Cache = _If<_UseCache, __non_propagating_cache<reverse_iterator<iterator_t<_View>>>, __empty_cache>;
+    [[no_unique_address]] _Cache __cached_begin_ = _Cache();
+    [[no_unique_address]] _View __base_ = _View();
+
+  public:
+    _LIBCPP_HIDE_FROM_ABI
+    reverse_view() requires default_initializable<_View> = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit reverse_view(_View __view) : __base_(_VSTD::move(__view)) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _View base() const& requires copy_constructible<_View> { return __base_; }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _View base() && { return _VSTD::move(__base_); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr reverse_iterator<iterator_t<_View>> begin() {
+      if constexpr (_UseCache)
+        if (__cached_begin_.__has_value())
+          return *__cached_begin_;
+
+      auto __tmp = _VSTD::make_reverse_iterator(ranges::next(ranges::begin(__base_), ranges::end(__base_)));
+      if constexpr (_UseCache)
+        __cached_begin_.__emplace(__tmp);
+      return __tmp;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr reverse_iterator<iterator_t<_View>> begin() requires common_range<_View> {
+      return _VSTD::make_reverse_iterator(ranges::end(__base_));
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto begin() const requires common_range<const _View> {
+      return _VSTD::make_reverse_iterator(ranges::end(__base_));
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr reverse_iterator<iterator_t<_View>> end() {
+      return _VSTD::make_reverse_iterator(ranges::begin(__base_));
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto end() const requires common_range<const _View> {
+      return _VSTD::make_reverse_iterator(ranges::begin(__base_));
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto size() requires sized_range<_View> {
+      return ranges::size(__base_);
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto size() const requires sized_range<const _View> {
+      return ranges::size(__base_);
+    }
+  };
+
+  template<class _Range>
+  reverse_view(_Range&&) -> reverse_view<views::all_t<_Range>>;
+
+  template<class _Tp>
+  inline constexpr bool enable_borrowed_range<reverse_view<_Tp>> = enable_borrowed_range<_Tp>;
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_REVERSE_VIEW_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/single_view.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/single_view.h
new file mode 100644
index 00000000000..412fa9b6464
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/single_view.h
@@ -0,0 +1,81 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_SINGLE_VIEW_H
+#define _LIBCPP___RANGES_SINGLE_VIEW_H
+
+#include <__config>
+#include <__ranges/view_interface.h>
+#include <__ranges/copyable_box.h>
+#include <__utility/forward.h>
+#include <__utility/in_place.h>
+#include <__utility/move.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+  template<copy_constructible _Tp>
+    requires is_object_v<_Tp>
+  class single_view : public view_interface<single_view<_Tp>> {
+    __copyable_box<_Tp> __value_;
+
+  public:
+    _LIBCPP_HIDE_FROM_ABI
+    single_view() requires default_initializable<_Tp> = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit single_view(const _Tp& __t) : __value_(in_place, __t) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit single_view(_Tp&& __t) : __value_(in_place, _VSTD::move(__t)) {}
+
+    template<class... _Args>
+      requires constructible_from<_Tp, _Args...>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit single_view(in_place_t, _Args&&... __args)
+      : __value_{in_place, _VSTD::forward<_Args>(__args)...} {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _Tp* begin() noexcept { return data(); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr const _Tp* begin() const noexcept { return data(); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _Tp* end() noexcept { return data() + 1; }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr const _Tp* end() const noexcept { return data() + 1; }
+
+    _LIBCPP_HIDE_FROM_ABI
+    static constexpr size_t size() noexcept { return 1; }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _Tp* data() noexcept { return __value_.operator->(); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr const _Tp* data() const noexcept { return __value_.operator->(); }
+  };
+
+  template<class _Tp>
+  single_view(_Tp) -> single_view<_Tp>;
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_SINGLE_VIEW_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/size.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/size.h
new file mode 100644
index 00000000000..af0a8479f2e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/size.h
@@ -0,0 +1,127 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_SIZE_H
+#define _LIBCPP___RANGES_SIZE_H
+
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/iterator_traits.h>
+#include <__ranges/access.h>
+#include <__utility/decay_copy.h>
+#include <__utility/forward.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+// clang-format off
+namespace ranges {
+template<class>
+inline constexpr bool disable_sized_range = false;
+
+// [range.prim.size]
+namespace __size {
+  void size(auto&) = delete;
+  void size(const auto&) = delete;
+
+  template <class _Tp>
+  concept __size_enabled = !disable_sized_range<remove_cvref_t<_Tp>>;
+
+  template <class _Tp>
+  concept __member_size = __size_enabled<_Tp> && requires(_Tp&& __t) {
+    { _VSTD::__decay_copy(_VSTD::forward<_Tp>(__t).size()) } -> __integer_like;
+  };
+
+  template <class _Tp>
+  concept __unqualified_size =
+    __size_enabled<_Tp> &&
+    !__member_size<_Tp> &&
+    __class_or_enum<remove_cvref_t<_Tp>> &&
+    requires(_Tp&& __t) {
+      { _VSTD::__decay_copy(size(_VSTD::forward<_Tp>(__t))) } -> __integer_like;
+    };
+
+  template <class _Tp>
+  concept __difference =
+    !__member_size<_Tp> &&
+    !__unqualified_size<_Tp> &&
+    __class_or_enum<remove_cvref_t<_Tp>> &&
+    requires(_Tp&& __t) {
+      { ranges::begin(__t) } -> forward_iterator;
+      { ranges::end(__t) } -> sized_sentinel_for<decltype(ranges::begin(declval<_Tp>()))>;
+    };
+
+  struct __fn {
+    template <class _Tp, size_t _Sz>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_t operator()(_Tp (&&)[_Sz]) const noexcept {
+      return _Sz;
+    }
+
+    template <class _Tp, size_t _Sz>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_t operator()(_Tp (&)[_Sz]) const noexcept {
+      return _Sz;
+    }
+
+    template <__member_size _Tp>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const
+        noexcept(noexcept(_VSTD::forward<_Tp>(__t).size())) {
+      return _VSTD::forward<_Tp>(__t).size();
+    }
+
+    template <__unqualified_size _Tp>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const
+        noexcept(noexcept(size(_VSTD::forward<_Tp>(__t)))) {
+      return size(_VSTD::forward<_Tp>(__t));
+    }
+
+    template<__difference _Tp>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const
+        noexcept(noexcept(ranges::end(__t) - ranges::begin(__t))) {
+      return _VSTD::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t));
+    }
+  };
+} // end namespace __size
+
+inline namespace __cpo {
+  inline constexpr auto size = __size::__fn{};
+} // namespace __cpo
+
+namespace __ssize {
+  struct __fn {
+    template<class _Tp>
+      requires requires (_Tp&& __t) { ranges::size(__t); }
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr integral auto operator()(_Tp&& __t) const
+        noexcept(noexcept(ranges::size(__t))) {
+      using _Signed = make_signed_t<decltype(ranges::size(__t))>;
+      if constexpr (sizeof(ptrdiff_t) > sizeof(_Signed))
+        return static_cast<ptrdiff_t>(ranges::size(__t));
+      else
+        return static_cast<_Signed>(ranges::size(__t));
+    }
+  };
+}
+
+inline namespace __cpo {
+  inline constexpr auto ssize = __ssize::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+// clang-format off
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_SIZE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/subrange.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/subrange.h
new file mode 100644
index 00000000000..af4e2760062
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/subrange.h
@@ -0,0 +1,287 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_SUBRANGE_H
+#define _LIBCPP___RANGES_SUBRANGE_H
+
+#include <__concepts/constructible.h>
+#include <__concepts/convertible_to.h>
+#include <__concepts/copyable.h>
+#include <__concepts/derived_from.h>
+#include <__concepts/different_from.h>
+#include <__config>
+#include <__debug>
+#include <__iterator/advance.h>
+#include <__iterator/concepts.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/iterator_traits.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/dangling.h>
+#include <__ranges/enable_borrowed_range.h>
+#include <__ranges/size.h>
+#include <__ranges/view_interface.h>
+#include <__tuple>
+#include <__utility/move.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+  template<class _From, class _To>
+  concept __convertible_to_non_slicing =
+    convertible_to<_From, _To> &&
+    // If they're both pointers, they must have the same element type.
+    !(is_pointer_v<decay_t<_From>> &&
+      is_pointer_v<decay_t<_To>> &&
+      __different_from<remove_pointer_t<decay_t<_From>>, remove_pointer_t<decay_t<_To>>>);
+
+  template<class _Tp>
+  concept __pair_like =
+    !is_reference_v<_Tp> && requires(_Tp __t) {
+      typename tuple_size<_Tp>::type; // Ensures `tuple_size<T>` is complete.
+      requires derived_from<tuple_size<_Tp>, integral_constant<size_t, 2>>;
+      typename tuple_element_t<0, remove_const_t<_Tp>>;
+      typename tuple_element_t<1, remove_const_t<_Tp>>;
+      { _VSTD::get<0>(__t) } -> convertible_to<const tuple_element_t<0, _Tp>&>;
+      { _VSTD::get<1>(__t) } -> convertible_to<const tuple_element_t<1, _Tp>&>;
+    };
+
+  template<class _Pair, class _Iter, class _Sent>
+  concept __pair_like_convertible_from =
+    !range<_Pair> && __pair_like<_Pair> &&
+    constructible_from<_Pair, _Iter, _Sent> &&
+    __convertible_to_non_slicing<_Iter, tuple_element_t<0, _Pair>> &&
+    convertible_to<_Sent, tuple_element_t<1, _Pair>>;
+
+  enum class _LIBCPP_ENUM_VIS subrange_kind : bool { unsized, sized };
+
+  template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent = _Iter,
+           subrange_kind _Kind = sized_sentinel_for<_Sent, _Iter>
+             ? subrange_kind::sized
+             : subrange_kind::unsized>
+    requires (_Kind == subrange_kind::sized || !sized_sentinel_for<_Sent, _Iter>)
+  class _LIBCPP_TEMPLATE_VIS subrange
+    : public view_interface<subrange<_Iter, _Sent, _Kind>>
+  {
+  private:
+    static constexpr bool _StoreSize = (_Kind == subrange_kind::sized && !sized_sentinel_for<_Sent, _Iter>);
+    static constexpr bool _MustProvideSizeAtConstruction = !_StoreSize; // just to improve compiler diagnostics
+    struct _Empty { constexpr _Empty(auto) noexcept { } };
+    using _Size = conditional_t<_StoreSize, make_unsigned_t<iter_difference_t<_Iter>>, _Empty>;
+    [[no_unique_address]] _Iter __begin_ = _Iter();
+    [[no_unique_address]] _Sent __end_ = _Sent();
+    [[no_unique_address]] _Size __size_ = 0;
+
+  public:
+    _LIBCPP_HIDE_FROM_ABI
+    subrange() requires default_initializable<_Iter> = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr subrange(__convertible_to_non_slicing<_Iter> auto __iter, _Sent __sent)
+      requires _MustProvideSizeAtConstruction
+      : __begin_(_VSTD::move(__iter)), __end_(std::move(__sent))
+    { }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr subrange(__convertible_to_non_slicing<_Iter> auto __iter, _Sent __sent,
+                       make_unsigned_t<iter_difference_t<_Iter>> __n)
+      requires (_Kind == subrange_kind::sized)
+      : __begin_(_VSTD::move(__iter)), __end_(std::move(__sent)), __size_(__n)
+    {
+      if constexpr (sized_sentinel_for<_Sent, _Iter>)
+        _LIBCPP_ASSERT((__end_ - __begin_) == static_cast<iter_difference_t<_Iter>>(__n),
+          "std::ranges::subrange was passed an invalid size hint");
+    }
+
+    template<__different_from<subrange> _Range>
+      requires borrowed_range<_Range> &&
+               __convertible_to_non_slicing<iterator_t<_Range>, _Iter> &&
+               convertible_to<sentinel_t<_Range>, _Sent>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr subrange(_Range&& __range)
+      requires (!_StoreSize)
+      : subrange(ranges::begin(__range), ranges::end(__range))
+    { }
+
+    template<__different_from<subrange> _Range>
+      requires borrowed_range<_Range> &&
+               __convertible_to_non_slicing<iterator_t<_Range>, _Iter> &&
+               convertible_to<sentinel_t<_Range>, _Sent>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr subrange(_Range&& __range)
+      requires _StoreSize && sized_range<_Range>
+      : subrange(__range, ranges::size(__range))
+    { }
+
+    template<borrowed_range _Range>
+      requires __convertible_to_non_slicing<iterator_t<_Range>, _Iter> &&
+               convertible_to<sentinel_t<_Range>, _Sent>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr subrange(_Range&& __range, make_unsigned_t<iter_difference_t<_Iter>> __n)
+      requires (_Kind == subrange_kind::sized)
+      : subrange(ranges::begin(__range), ranges::end(__range), __n)
+    { }
+
+    template<__different_from<subrange> _Pair>
+      requires __pair_like_convertible_from<_Pair, const _Iter&, const _Sent&>
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr operator _Pair() const {
+      return _Pair(__begin_, __end_);
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _Iter begin() const requires copyable<_Iter> {
+      return __begin_;
+    }
+
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Iter begin() requires (!copyable<_Iter>) {
+      return _VSTD::move(__begin_);
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _Sent end() const {
+      return __end_;
+    }
+
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const {
+      return __begin_ == __end_;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr make_unsigned_t<iter_difference_t<_Iter>> size() const
+      requires (_Kind == subrange_kind::sized)
+    {
+      if constexpr (_StoreSize)
+        return __size_;
+      else
+        return _VSTD::__to_unsigned_like(__end_ - __begin_);
+    }
+
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange next(iter_difference_t<_Iter> __n = 1) const&
+      requires forward_iterator<_Iter>
+    {
+      auto __tmp = *this;
+      __tmp.advance(__n);
+      return __tmp;
+    }
+
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange next(iter_difference_t<_Iter> __n = 1) && {
+      advance(__n);
+      return _VSTD::move(*this);
+    }
+
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange prev(iter_difference_t<_Iter> __n = 1) const
+      requires bidirectional_iterator<_Iter>
+    {
+      auto __tmp = *this;
+      __tmp.advance(-__n);
+      return __tmp;
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr subrange& advance(iter_difference_t<_Iter> __n) {
+      if constexpr (bidirectional_iterator<_Iter>) {
+        if (__n < 0) {
+          ranges::advance(__begin_, __n);
+          if constexpr (_StoreSize)
+            __size_ += _VSTD::__to_unsigned_like(-__n);
+          return *this;
+        }
+      }
+
+      auto __d = __n - ranges::advance(__begin_, __n, __end_);
+      if constexpr (_StoreSize)
+        __size_ -= _VSTD::__to_unsigned_like(__d);
+      return *this;
+    }
+  };
+
+  template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent>
+  subrange(_Iter, _Sent) -> subrange<_Iter, _Sent>;
+
+  template<input_or_output_iterator _Iter, sentinel_for<_Iter> _Sent>
+  subrange(_Iter, _Sent, make_unsigned_t<iter_difference_t<_Iter>>)
+    -> subrange<_Iter, _Sent, subrange_kind::sized>;
+
+  template<borrowed_range _Range>
+  subrange(_Range&&) -> subrange<iterator_t<_Range>, sentinel_t<_Range>,
+                                 (sized_range<_Range> || sized_sentinel_for<sentinel_t<_Range>, iterator_t<_Range>>)
+                                   ? subrange_kind::sized : subrange_kind::unsized>;
+
+  template<borrowed_range _Range>
+  subrange(_Range&&, make_unsigned_t<range_difference_t<_Range>>)
+    -> subrange<iterator_t<_Range>, sentinel_t<_Range>, subrange_kind::sized>;
+
+  template<size_t _Index, class _Iter, class _Sent, subrange_kind _Kind>
+    requires (_Index < 2)
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto get(const subrange<_Iter, _Sent, _Kind>& __subrange) {
+    if constexpr (_Index == 0)
+      return __subrange.begin();
+    else
+      return __subrange.end();
+  }
+
+  template<size_t _Index, class _Iter, class _Sent, subrange_kind _Kind>
+    requires (_Index < 2)
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto get(subrange<_Iter, _Sent, _Kind>&& __subrange) {
+    if constexpr (_Index == 0)
+      return __subrange.begin();
+    else
+      return __subrange.end();
+  }
+
+  template<class _Ip, class _Sp, subrange_kind _Kp>
+  inline constexpr bool enable_borrowed_range<subrange<_Ip, _Sp, _Kp>> = true;
+
+  template<range _Rp>
+  using borrowed_subrange_t = _If<borrowed_range<_Rp>, subrange<iterator_t<_Rp>>, dangling>;
+} // namespace ranges
+
+// [range.subrange.general]
+
+using ranges::get;
+
+// [ranges.syn]
+
+template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
+struct tuple_size<ranges::subrange<_Ip, _Sp, _Kp>> : integral_constant<size_t, 2> {};
+
+template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
+struct tuple_element<0, ranges::subrange<_Ip, _Sp, _Kp>> {
+  using type = _Ip;
+};
+
+template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
+struct tuple_element<1, ranges::subrange<_Ip, _Sp, _Kp>> {
+  using type = _Sp;
+};
+
+template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
+struct tuple_element<0, const ranges::subrange<_Ip, _Sp, _Kp>> {
+  using type = _Ip;
+};
+
+template<class _Ip, class _Sp, ranges::subrange_kind _Kp>
+struct tuple_element<1, const ranges::subrange<_Ip, _Sp, _Kp>> {
+  using type = _Sp;
+};
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_SUBRANGE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/take_view.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/take_view.h
new file mode 100644
index 00000000000..73a57fe96c0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/take_view.h
@@ -0,0 +1,185 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_TAKE_VIEW_H
+#define _LIBCPP___RANGES_TAKE_VIEW_H
+
+#include <__algorithm/min.h>
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__iterator/counted_iterator.h>
+#include <__iterator/default_sentinel.h>
+#include <__iterator/iterator_traits.h>
+#include <__ranges/access.h>
+#include <__ranges/all.h>
+#include <__ranges/concepts.h>
+#include <__ranges/enable_borrowed_range.h>
+#include <__ranges/size.h>
+#include <__ranges/view_interface.h>
+#include <__utility/move.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+  template<view _View>
+  class take_view : public view_interface<take_view<_View>> {
+    [[no_unique_address]] _View __base_ = _View();
+    range_difference_t<_View> __count_ = 0;
+
+    template<bool> class __sentinel;
+
+  public:
+    _LIBCPP_HIDE_FROM_ABI
+    take_view() requires default_initializable<_View> = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr take_view(_View __base, range_difference_t<_View> __count)
+      : __base_(_VSTD::move(__base)), __count_(__count) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _View base() const& requires copy_constructible<_View> { return __base_; }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr _View base() && { return _VSTD::move(__base_); }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto begin() requires (!__simple_view<_View>) {
+      if constexpr (sized_range<_View>) {
+        if constexpr (random_access_range<_View>) {
+          return ranges::begin(__base_);
+        } else {
+          using _DifferenceT = range_difference_t<_View>;
+          auto __size = size();
+          return counted_iterator(ranges::begin(__base_), static_cast<_DifferenceT>(__size));
+        }
+      } else {
+        return counted_iterator(ranges::begin(__base_), __count_);
+      }
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto begin() const requires range<const _View> {
+      if constexpr (sized_range<const _View>) {
+        if constexpr (random_access_range<const _View>) {
+          return ranges::begin(__base_);
+        } else {
+          using _DifferenceT = range_difference_t<const _View>;
+          auto __size = size();
+          return counted_iterator(ranges::begin(__base_), static_cast<_DifferenceT>(__size));
+        }
+      } else {
+        return counted_iterator(ranges::begin(__base_), __count_);
+      }
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto end() requires (!__simple_view<_View>) {
+      if constexpr (sized_range<_View>) {
+        if constexpr (random_access_range<_View>) {
+          return ranges::begin(__base_) + size();
+        } else {
+          return default_sentinel;
+        }
+      } else {
+        return __sentinel<false>{ranges::end(__base_)};
+      }
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto end() const requires range<const _View> {
+      if constexpr (sized_range<const _View>) {
+        if constexpr (random_access_range<const _View>) {
+          return ranges::begin(__base_) + size();
+        } else {
+          return default_sentinel;
+        }
+      } else {
+        return __sentinel<true>{ranges::end(__base_)};
+      }
+    }
+
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto size() requires sized_range<_View> {
+      auto __n = ranges::size(__base_);
+      // TODO: use ranges::min here.
+      return _VSTD::min(__n, static_cast<decltype(__n)>(__count_));
+    }
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr auto size() const requires sized_range<const _View> {
+      auto __n = ranges::size(__base_);
+      // TODO: use ranges::min here.
+      return _VSTD::min(__n, static_cast<decltype(__n)>(__count_));
+    }
+  };
+
+  template<view _View>
+  template<bool _Const>
+  class take_view<_View>::__sentinel {
+    using _Base = __maybe_const<_Const, _View>;
+    template<bool _OtherConst>
+    using _Iter = counted_iterator<iterator_t<__maybe_const<_OtherConst, _View>>>;
+    [[no_unique_address]] sentinel_t<_Base> __end_ = sentinel_t<_Base>();
+
+    template<bool>
+    friend class take_view<_View>::__sentinel;
+
+public:
+    _LIBCPP_HIDE_FROM_ABI
+    __sentinel() = default;
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr explicit __sentinel(sentinel_t<_Base> __end) : __end_(_VSTD::move(__end)) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr __sentinel(__sentinel<!_Const> __s)
+      requires _Const && convertible_to<sentinel_t<_View>, sentinel_t<_Base>>
+      : __end_(_VSTD::move(__s.__end_)) {}
+
+    _LIBCPP_HIDE_FROM_ABI
+    constexpr sentinel_t<_Base> base() const { return __end_; }
+
+    _LIBCPP_HIDE_FROM_ABI
+    friend constexpr bool operator==(const _Iter<_Const>& __lhs, const __sentinel& __rhs) {
+      return __lhs.count() == 0 || __lhs.base() == __rhs.__end_;
+    }
+
+    template<bool _OtherConst = !_Const>
+      requires sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
+    _LIBCPP_HIDE_FROM_ABI
+    friend constexpr bool operator==(const _Iter<_Const>& __lhs, const __sentinel& __rhs) {
+      return __lhs.count() == 0 || __lhs.base() == __rhs.__end_;
+    }
+  };
+
+  template<class _Range>
+  take_view(_Range&&, range_difference_t<_Range>) -> take_view<views::all_t<_Range>>;
+
+  template<class _Tp>
+  inline constexpr bool enable_borrowed_range<take_view<_Tp>> = enable_borrowed_range<_Tp>;
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___RANGES_TAKE_VIEW_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/transform_view.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/transform_view.h
new file mode 100644
index 00000000000..de1296cbd26
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/transform_view.h
@@ -0,0 +1,441 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_TRANSFORM_VIEW_H
+#define _LIBCPP___RANGES_TRANSFORM_VIEW_H
+
+#include <__compare/three_way_comparable.h>
+#include <__concepts/constructible.h>
+#include <__concepts/convertible_to.h>
+#include <__concepts/copyable.h>
+#include <__concepts/derived_from.h>
+#include <__concepts/equality_comparable.h>
+#include <__concepts/invocable.h>
+#include <__config>
+#include <__functional/bind_back.h>
+#include <__functional/invoke.h>
+#include <__iterator/concepts.h>
+#include <__iterator/iter_swap.h>
+#include <__iterator/iterator_traits.h>
+#include <__memory/addressof.h>
+#include <__ranges/access.h>
+#include <__ranges/all.h>
+#include <__ranges/concepts.h>
+#include <__ranges/copyable_box.h>
+#include <__ranges/empty.h>
+#include <__ranges/range_adaptor.h>
+#include <__ranges/size.h>
+#include <__ranges/view_interface.h>
+#include <__utility/forward.h>
+#include <__utility/in_place.h>
+#include <__utility/move.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+
+template<class _View, class _Fn>
+concept __transform_view_constraints =
+           view<_View> && is_object_v<_Fn> &&
+           regular_invocable<_Fn&, range_reference_t<_View>> &&
+           __referenceable<invoke_result_t<_Fn&, range_reference_t<_View>>>;
+
+template<input_range _View, copy_constructible _Fn>
+  requires __transform_view_constraints<_View, _Fn>
+class transform_view : public view_interface<transform_view<_View, _Fn>> {
+  template<bool> class __iterator;
+  template<bool> class __sentinel;
+
+  [[no_unique_address]] __copyable_box<_Fn> __func_;
+  [[no_unique_address]] _View __base_ = _View();
+
+public:
+  _LIBCPP_HIDE_FROM_ABI
+  transform_view()
+    requires default_initializable<_View> && default_initializable<_Fn> = default;
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr transform_view(_View __base, _Fn __func)
+    : __func_(_VSTD::in_place, _VSTD::move(__func)), __base_(_VSTD::move(__base)) {}
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _View base() const& requires copy_constructible<_View> { return __base_; }
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _View base() && { return _VSTD::move(__base_); }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator<false> begin() {
+    return __iterator<false>{*this, ranges::begin(__base_)};
+  }
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator<true> begin() const
+    requires range<const _View> &&
+             regular_invocable<const _Fn&, range_reference_t<const _View>>
+  {
+    return __iterator<true>(*this, ranges::begin(__base_));
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __sentinel<false> end() {
+    return __sentinel<false>(ranges::end(__base_));
+  }
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator<false> end()
+    requires common_range<_View>
+  {
+    return __iterator<false>(*this, ranges::end(__base_));
+  }
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __sentinel<true> end() const
+    requires range<const _View> &&
+             regular_invocable<const _Fn&, range_reference_t<const _View>>
+  {
+    return __sentinel<true>(ranges::end(__base_));
+  }
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator<true> end() const
+    requires common_range<const _View> &&
+             regular_invocable<const _Fn&, range_reference_t<const _View>>
+  {
+    return __iterator<true>(*this, ranges::end(__base_));
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto size() requires sized_range<_View> { return ranges::size(__base_); }
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto size() const requires sized_range<const _View> { return ranges::size(__base_); }
+};
+
+template<class _Range, class _Fn>
+transform_view(_Range&&, _Fn) -> transform_view<views::all_t<_Range>, _Fn>;
+
+template<class _View>
+struct __transform_view_iterator_concept { using type = input_iterator_tag; };
+
+template<random_access_range _View>
+struct __transform_view_iterator_concept<_View> { using type = random_access_iterator_tag; };
+
+template<bidirectional_range _View>
+struct __transform_view_iterator_concept<_View> { using type = bidirectional_iterator_tag; };
+
+template<forward_range _View>
+struct __transform_view_iterator_concept<_View> { using type = forward_iterator_tag; };
+
+template<class, class>
+struct __transform_view_iterator_category_base {};
+
+template<forward_range _View, class _Fn>
+struct __transform_view_iterator_category_base<_View, _Fn> {
+  using _Cat = typename iterator_traits<iterator_t<_View>>::iterator_category;
+
+  using iterator_category = conditional_t<
+    is_lvalue_reference_v<invoke_result_t<_Fn&, range_reference_t<_View>>>,
+    conditional_t<
+      derived_from<_Cat, contiguous_iterator_tag>,
+      random_access_iterator_tag,
+      _Cat
+    >,
+    input_iterator_tag
+  >;
+};
+
+template<input_range _View, copy_constructible _Fn>
+  requires __transform_view_constraints<_View, _Fn>
+template<bool _Const>
+class transform_view<_View, _Fn>::__iterator
+  : public __transform_view_iterator_category_base<_View, _Fn> {
+
+  using _Parent = __maybe_const<_Const, transform_view>;
+  using _Base = __maybe_const<_Const, _View>;
+
+  _Parent *__parent_ = nullptr;
+
+  template<bool>
+  friend class transform_view<_View, _Fn>::__iterator;
+
+  template<bool>
+  friend class transform_view<_View, _Fn>::__sentinel;
+
+public:
+  iterator_t<_Base> __current_ = iterator_t<_Base>();
+
+  using iterator_concept = typename __transform_view_iterator_concept<_View>::type;
+  using value_type = remove_cvref_t<invoke_result_t<_Fn&, range_reference_t<_Base>>>;
+  using difference_type = range_difference_t<_Base>;
+
+  _LIBCPP_HIDE_FROM_ABI
+  __iterator() requires default_initializable<iterator_t<_Base>> = default;
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator(_Parent& __parent, iterator_t<_Base> __current)
+    : __parent_(_VSTD::addressof(__parent)), __current_(_VSTD::move(__current)) {}
+
+  // Note: `__i` should always be `__iterator<false>`, but directly using
+  // `__iterator<false>` is ill-formed when `_Const` is false
+  // (see http://wg21.link/class.copy.ctor#5).
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator(__iterator<!_Const> __i)
+    requires _Const && convertible_to<iterator_t<_View>, iterator_t<_Base>>
+    : __parent_(__i.__parent_), __current_(_VSTD::move(__i.__current_)) {}
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr iterator_t<_Base> base() const&
+    requires copyable<iterator_t<_Base>>
+  {
+    return __current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr iterator_t<_Base> base() && {
+    return _VSTD::move(__current_);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr decltype(auto) operator*() const
+    noexcept(noexcept(_VSTD::invoke(*__parent_->__func_, *__current_)))
+  {
+    return _VSTD::invoke(*__parent_->__func_, *__current_);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator& operator++() {
+    ++__current_;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr void operator++(int) { ++__current_; }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator operator++(int)
+    requires forward_range<_Base>
+  {
+    auto __tmp = *this;
+    ++*this;
+    return __tmp;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator& operator--()
+    requires bidirectional_range<_Base>
+  {
+    --__current_;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator operator--(int)
+    requires bidirectional_range<_Base>
+  {
+    auto __tmp = *this;
+    --*this;
+    return __tmp;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator& operator+=(difference_type __n)
+    requires random_access_range<_Base>
+  {
+    __current_ += __n;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __iterator& operator-=(difference_type __n)
+    requires random_access_range<_Base>
+  {
+    __current_ -= __n;
+    return *this;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr decltype(auto) operator[](difference_type __n) const
+    noexcept(noexcept(_VSTD::invoke(*__parent_->__func_, __current_[__n])))
+    requires random_access_range<_Base>
+  {
+    return _VSTD::invoke(*__parent_->__func_, __current_[__n]);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator==(const __iterator& __x, const __iterator& __y)
+    requires equality_comparable<iterator_t<_Base>>
+  {
+    return __x.__current_ == __y.__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator<(const __iterator& __x, const __iterator& __y)
+    requires random_access_range<_Base>
+  {
+    return __x.__current_ < __y.__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator>(const __iterator& __x, const __iterator& __y)
+    requires random_access_range<_Base>
+  {
+    return __x.__current_ > __y.__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator<=(const __iterator& __x, const __iterator& __y)
+    requires random_access_range<_Base>
+  {
+    return __x.__current_ <= __y.__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator>=(const __iterator& __x, const __iterator& __y)
+    requires random_access_range<_Base>
+  {
+    return __x.__current_ >= __y.__current_;
+  }
+
+#if !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR)
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr auto operator<=>(const __iterator& __x, const __iterator& __y)
+    requires random_access_range<_Base> && three_way_comparable<iterator_t<_Base>>
+  {
+    return __x.__current_ <=> __y.__current_;
+  }
+#endif // !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR)
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr __iterator operator+(__iterator __i, difference_type __n)
+    requires random_access_range<_Base>
+  {
+    return __iterator{*__i.__parent_, __i.__current_ + __n};
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr __iterator operator+(difference_type __n, __iterator __i)
+    requires random_access_range<_Base>
+  {
+    return __iterator{*__i.__parent_, __i.__current_ + __n};
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr __iterator operator-(__iterator __i, difference_type __n)
+    requires random_access_range<_Base>
+  {
+    return __iterator{*__i.__parent_, __i.__current_ - __n};
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr difference_type operator-(const __iterator& __x, const __iterator& __y)
+    requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>
+  {
+    return __x.__current_ - __y.__current_;
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr decltype(auto) iter_move(const __iterator& __i)
+    noexcept(noexcept(*__i))
+  {
+    if constexpr (is_lvalue_reference_v<decltype(*__i)>)
+      return _VSTD::move(*__i);
+    else
+      return *__i;
+  }
+};
+
+template<input_range _View, copy_constructible _Fn>
+  requires __transform_view_constraints<_View, _Fn>
+template<bool _Const>
+class transform_view<_View, _Fn>::__sentinel {
+  using _Parent = __maybe_const<_Const, transform_view>;
+  using _Base = __maybe_const<_Const, _View>;
+
+  sentinel_t<_Base> __end_ = sentinel_t<_Base>();
+
+  template<bool>
+  friend class transform_view<_View, _Fn>::__iterator;
+
+  template<bool>
+  friend class transform_view<_View, _Fn>::__sentinel;
+
+public:
+  _LIBCPP_HIDE_FROM_ABI
+  __sentinel() = default;
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr explicit __sentinel(sentinel_t<_Base> __end) : __end_(__end) {}
+
+  // Note: `__i` should always be `__sentinel<false>`, but directly using
+  // `__sentinel<false>` is ill-formed when `_Const` is false
+  // (see http://wg21.link/class.copy.ctor#5).
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr __sentinel(__sentinel<!_Const> __i)
+    requires _Const && convertible_to<sentinel_t<_View>, sentinel_t<_Base>>
+    : __end_(_VSTD::move(__i.__end_)) {}
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr sentinel_t<_Base> base() const { return __end_; }
+
+  template<bool _OtherConst>
+    requires sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr bool operator==(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
+    return __x.__current_ == __y.__end_;
+  }
+
+  template<bool _OtherConst>
+    requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr range_difference_t<__maybe_const<_OtherConst, _View>>
+  operator-(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
+    return __x.__current_ - __y.__end_;
+  }
+
+  template<bool _OtherConst>
+    requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
+  _LIBCPP_HIDE_FROM_ABI
+  friend constexpr range_difference_t<__maybe_const<_OtherConst, _View>>
+  operator-(const __sentinel& __x, const __iterator<_OtherConst>& __y) {
+    return __x.__end_ - __y.__current_;
+  }
+};
+
+namespace views {
+namespace __transform {
+  struct __fn {
+    template<class _Range, class _Fn>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Range&& __range, _Fn&& __f) const
+      noexcept(noexcept(transform_view(_VSTD::forward<_Range>(__range), _VSTD::forward<_Fn>(__f))))
+      -> decltype(      transform_view(_VSTD::forward<_Range>(__range), _VSTD::forward<_Fn>(__f)))
+      { return          transform_view(_VSTD::forward<_Range>(__range), _VSTD::forward<_Fn>(__f)); }
+
+    template<class _Fn>
+      requires constructible_from<decay_t<_Fn>, _Fn>
+    [[nodiscard]] _LIBCPP_HIDE_FROM_ABI
+    constexpr auto operator()(_Fn&& __f) const
+      noexcept(is_nothrow_constructible_v<decay_t<_Fn>, _Fn>)
+    { return __range_adaptor_closure_t(_VSTD::__bind_back(*this, _VSTD::forward<_Fn>(__f))); }
+  };
+}
+
+inline namespace __cpo {
+  inline constexpr auto transform = __transform::__fn{};
+}
+} // namespace views
+
+} // namespace ranges
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_TRANSFORM_VIEW_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__ranges/view_interface.h b/contrib/libs/cxxsupp/libcxx/include/__ranges/view_interface.h
new file mode 100644
index 00000000000..1c66dadfa1e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__ranges/view_interface.h
@@ -0,0 +1,194 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP___RANGES_VIEW_INTERFACE_H
+#define _LIBCPP___RANGES_VIEW_INTERFACE_H
+
+#include <__config>
+#include <__debug>
+#include <__iterator/concepts.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/prev.h>
+#include <__memory/pointer_traits.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/empty.h>
+#include <__ranges/enable_view.h>
+#include <concepts>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace ranges {
+
+template<class _Tp>
+concept __can_empty = requires(_Tp __t) { ranges::empty(__t); };
+
+template<class _Tp>
+void __implicitly_convert_to(type_identity_t<_Tp>) noexcept;
+
+template<class _Derived>
+  requires is_class_v<_Derived> && same_as<_Derived, remove_cv_t<_Derived>>
+class view_interface : public view_base {
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _Derived& __derived() noexcept {
+    return static_cast<_Derived&>(*this);
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr _Derived const& __derived() const noexcept {
+    return static_cast<_Derived const&>(*this);
+  }
+
+public:
+  template<class _D2 = _Derived>
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty()
+    noexcept(noexcept(__implicitly_convert_to<bool>(ranges::begin(__derived()) == ranges::end(__derived()))))
+    requires forward_range<_D2>
+  {
+    return ranges::begin(__derived()) == ranges::end(__derived());
+  }
+
+  template<class _D2 = _Derived>
+  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr bool empty() const
+    noexcept(noexcept(__implicitly_convert_to<bool>(ranges::begin(__derived()) == ranges::end(__derived()))))
+    requires forward_range<const _D2>
+  {
+    return ranges::begin(__derived()) == ranges::end(__derived());
+  }
+
+  template<class _D2 = _Derived>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr explicit operator bool()
+    noexcept(noexcept(ranges::empty(declval<_D2>())))
+    requires __can_empty<_D2>
+  {
+    return !ranges::empty(__derived());
+  }
+
+  template<class _D2 = _Derived>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr explicit operator bool() const
+    noexcept(noexcept(ranges::empty(declval<const _D2>())))
+    requires __can_empty<const _D2>
+  {
+    return !ranges::empty(__derived());
+  }
+
+  template<class _D2 = _Derived>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto data()
+    noexcept(noexcept(_VSTD::to_address(ranges::begin(__derived()))))
+    requires contiguous_iterator<iterator_t<_D2>>
+  {
+    return _VSTD::to_address(ranges::begin(__derived()));
+  }
+
+  template<class _D2 = _Derived>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto data() const
+    noexcept(noexcept(_VSTD::to_address(ranges::begin(__derived()))))
+    requires range<const _D2> && contiguous_iterator<iterator_t<const _D2>>
+  {
+    return _VSTD::to_address(ranges::begin(__derived()));
+  }
+
+  template<class _D2 = _Derived>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto size()
+    noexcept(noexcept(ranges::end(__derived()) - ranges::begin(__derived())))
+    requires forward_range<_D2>
+      && sized_sentinel_for<sentinel_t<_D2>, iterator_t<_D2>>
+  {
+    return ranges::end(__derived()) - ranges::begin(__derived());
+  }
+
+  template<class _D2 = _Derived>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr auto size() const
+    noexcept(noexcept(ranges::end(__derived()) - ranges::begin(__derived())))
+    requires forward_range<const _D2>
+      && sized_sentinel_for<sentinel_t<const _D2>, iterator_t<const _D2>>
+  {
+    return ranges::end(__derived()) - ranges::begin(__derived());
+  }
+
+  template<class _D2 = _Derived>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr decltype(auto) front()
+    noexcept(noexcept(*ranges::begin(__derived())))
+    requires forward_range<_D2>
+  {
+    _LIBCPP_ASSERT(!empty(),
+        "Precondition `!empty()` not satisfied. `.front()` called on an empty view.");
+    return *ranges::begin(__derived());
+  }
+
+  template<class _D2 = _Derived>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr decltype(auto) front() const
+    noexcept(noexcept(*ranges::begin(__derived())))
+    requires forward_range<const _D2>
+  {
+    _LIBCPP_ASSERT(!empty(),
+        "Precondition `!empty()` not satisfied. `.front()` called on an empty view.");
+    return *ranges::begin(__derived());
+  }
+
+  template<class _D2 = _Derived>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr decltype(auto) back()
+    noexcept(noexcept(*ranges::prev(ranges::end(__derived()))))
+    requires bidirectional_range<_D2> && common_range<_D2>
+  {
+    _LIBCPP_ASSERT(!empty(),
+        "Precondition `!empty()` not satisfied. `.back()` called on an empty view.");
+    return *ranges::prev(ranges::end(__derived()));
+  }
+
+  template<class _D2 = _Derived>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr decltype(auto) back() const
+    noexcept(noexcept(*ranges::prev(ranges::end(__derived()))))
+    requires bidirectional_range<const _D2> && common_range<const _D2>
+  {
+    _LIBCPP_ASSERT(!empty(),
+        "Precondition `!empty()` not satisfied. `.back()` called on an empty view.");
+    return *ranges::prev(ranges::end(__derived()));
+  }
+
+  template<random_access_range _RARange = _Derived>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr decltype(auto) operator[](range_difference_t<_RARange> __index)
+    noexcept(noexcept(ranges::begin(__derived())[__index]))
+  {
+    return ranges::begin(__derived())[__index];
+  }
+
+  template<random_access_range _RARange = const _Derived>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr decltype(auto) operator[](range_difference_t<_RARange> __index) const
+    noexcept(noexcept(ranges::begin(__derived())[__index]))
+  {
+    return ranges::begin(__derived())[__index];
+  }
+};
+
+}
+
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___RANGES_VIEW_INTERFACE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__split_buffer b/contrib/libs/cxxsupp/libcxx/include/__split_buffer
new file mode 100644
index 00000000000..0bff575323a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__split_buffer
@@ -0,0 +1,628 @@
+// -*- C++ -*-
+#ifndef _LIBCPP_SPLIT_BUFFER
+#define _LIBCPP_SPLIT_BUFFER
+
+#include <__config>
+#include <__utility/forward.h>
+#include <algorithm>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class _Allocator = allocator<_Tp> >
+struct __split_buffer
+{
+private:
+    __split_buffer(const __split_buffer&);
+    __split_buffer& operator=(const __split_buffer&);
+public:
+    typedef _Tp                                             value_type;
+    typedef _Allocator                                      allocator_type;
+    typedef typename remove_reference<allocator_type>::type __alloc_rr;
+    typedef allocator_traits<__alloc_rr>                    __alloc_traits;
+    typedef value_type&                                     reference;
+    typedef const value_type&                               const_reference;
+    typedef typename __alloc_traits::size_type              size_type;
+    typedef typename __alloc_traits::difference_type        difference_type;
+    typedef typename __alloc_traits::pointer                pointer;
+    typedef typename __alloc_traits::const_pointer          const_pointer;
+    typedef pointer                                         iterator;
+    typedef const_pointer                                   const_iterator;
+
+    pointer                                         __first_;
+    pointer                                         __begin_;
+    pointer                                         __end_;
+    __compressed_pair<pointer, allocator_type> __end_cap_;
+
+    typedef typename add_lvalue_reference<allocator_type>::type __alloc_ref;
+    typedef typename add_lvalue_reference<allocator_type>::type __alloc_const_ref;
+
+    _LIBCPP_INLINE_VISIBILITY __alloc_rr&           __alloc() _NOEXCEPT         {return __end_cap_.second();}
+    _LIBCPP_INLINE_VISIBILITY const __alloc_rr&     __alloc() const _NOEXCEPT   {return __end_cap_.second();}
+    _LIBCPP_INLINE_VISIBILITY pointer&              __end_cap() _NOEXCEPT       {return __end_cap_.first();}
+    _LIBCPP_INLINE_VISIBILITY const pointer&        __end_cap() const _NOEXCEPT {return __end_cap_.first();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __split_buffer()
+        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __split_buffer(__alloc_rr& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __split_buffer(const __alloc_rr& __a);
+    __split_buffer(size_type __cap, size_type __start, __alloc_rr& __a);
+    ~__split_buffer();
+
+    __split_buffer(__split_buffer&& __c)
+        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value);
+    __split_buffer(__split_buffer&& __c, const __alloc_rr& __a);
+    __split_buffer& operator=(__split_buffer&& __c)
+        _NOEXCEPT_((__alloc_traits::propagate_on_container_move_assignment::value &&
+                is_nothrow_move_assignable<allocator_type>::value) ||
+               !__alloc_traits::propagate_on_container_move_assignment::value);
+
+    _LIBCPP_INLINE_VISIBILITY       iterator begin() _NOEXCEPT       {return __begin_;}
+    _LIBCPP_INLINE_VISIBILITY const_iterator begin() const _NOEXCEPT {return __begin_;}
+    _LIBCPP_INLINE_VISIBILITY       iterator end() _NOEXCEPT         {return __end_;}
+    _LIBCPP_INLINE_VISIBILITY const_iterator end() const _NOEXCEPT   {return __end_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT
+        {__destruct_at_end(__begin_);}
+    _LIBCPP_INLINE_VISIBILITY size_type size() const {return static_cast<size_type>(__end_ - __begin_);}
+    _LIBCPP_INLINE_VISIBILITY bool empty()     const {return __end_ == __begin_;}
+    _LIBCPP_INLINE_VISIBILITY size_type capacity() const {return static_cast<size_type>(__end_cap() - __first_);}
+    _LIBCPP_INLINE_VISIBILITY size_type __front_spare() const {return static_cast<size_type>(__begin_ - __first_);}
+    _LIBCPP_INLINE_VISIBILITY size_type __back_spare() const {return static_cast<size_type>(__end_cap() - __end_);}
+
+    _LIBCPP_INLINE_VISIBILITY       reference front()       {return *__begin_;}
+    _LIBCPP_INLINE_VISIBILITY const_reference front() const {return *__begin_;}
+    _LIBCPP_INLINE_VISIBILITY       reference back()        {return *(__end_ - 1);}
+    _LIBCPP_INLINE_VISIBILITY const_reference back() const  {return *(__end_ - 1);}
+
+    void reserve(size_type __n);
+    void shrink_to_fit() _NOEXCEPT;
+    void push_front(const_reference __x);
+    _LIBCPP_INLINE_VISIBILITY void push_back(const_reference __x);
+    void push_front(value_type&& __x);
+    void push_back(value_type&& __x);
+    template <class... _Args>
+        void emplace_back(_Args&&... __args);
+
+    _LIBCPP_INLINE_VISIBILITY void pop_front() {__destruct_at_begin(__begin_+1);}
+    _LIBCPP_INLINE_VISIBILITY void pop_back() {__destruct_at_end(__end_-1);}
+
+    void __uninitialized_at_end(size_type __n);
+    void __construct_at_end(size_type __n);
+    void __construct_at_end(size_type __n, const_reference __x);
+    template <class _InputIter>
+        typename enable_if
+        <
+            __is_cpp17_input_iterator<_InputIter>::value &&
+           !__is_cpp17_forward_iterator<_InputIter>::value,
+            void
+        >::type
+        __construct_at_end(_InputIter __first, _InputIter __last);
+    template <class _ForwardIterator>
+        typename enable_if
+        <
+            __is_cpp17_forward_iterator<_ForwardIterator>::value,
+            void
+        >::type
+        __construct_at_end(_ForwardIterator __first, _ForwardIterator __last);
+
+    _LIBCPP_INLINE_VISIBILITY void __destruct_at_begin(pointer __new_begin)
+        {__destruct_at_begin(__new_begin, is_trivially_destructible<value_type>());}
+        _LIBCPP_INLINE_VISIBILITY
+        void __destruct_at_begin(pointer __new_begin, false_type);
+        _LIBCPP_INLINE_VISIBILITY
+        void __destruct_at_begin(pointer __new_begin, true_type);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __destruct_at_end(pointer __new_last) _NOEXCEPT
+        {__destruct_at_end(__new_last, false_type());}
+    _LIBCPP_INLINE_VISIBILITY
+        void __destruct_at_end(pointer __new_last, false_type) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+        void __destruct_at_end(pointer __new_last, true_type) _NOEXCEPT;
+
+    void swap(__split_buffer& __x)
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value||
+                   __is_nothrow_swappable<__alloc_rr>::value);
+
+    bool __invariants() const;
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__split_buffer& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
+        {
+            __alloc() = _VSTD::move(__c.__alloc());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__split_buffer&, false_type) _NOEXCEPT
+        {}
+
+    struct _ConstructTransaction {
+      explicit _ConstructTransaction(pointer* __p, size_type __n) _NOEXCEPT
+      : __pos_(*__p), __end_(*__p + __n), __dest_(__p) {
+      }
+      ~_ConstructTransaction() {
+        *__dest_ = __pos_;
+      }
+      pointer __pos_;
+     const pointer __end_;
+    private:
+     pointer *__dest_;
+    };
+};
+
+template <class _Tp, class _Allocator>
+bool
+__split_buffer<_Tp, _Allocator>::__invariants() const
+{
+    if (__first_ == nullptr)
+    {
+        if (__begin_ != nullptr)
+            return false;
+        if (__end_ != nullptr)
+            return false;
+        if (__end_cap() != nullptr)
+            return false;
+    }
+    else
+    {
+        if (__begin_ < __first_)
+            return false;
+        if (__end_ < __begin_)
+            return false;
+        if (__end_cap() < __end_)
+            return false;
+    }
+    return true;
+}
+
+template <class _Tp, class _Allocator>
+void
+__split_buffer<_Tp, _Allocator>::__uninitialized_at_end(size_type __n)
+{
+    this->__end_ += __n;
+}
+
+//  Default constructs __n objects starting at __end_
+//  throws if construction throws
+//  Precondition:  __n > 0
+//  Precondition:  size() + __n <= capacity()
+//  Postcondition:  size() == size() + __n
+template <class _Tp, class _Allocator>
+void
+__split_buffer<_Tp, _Allocator>::__construct_at_end(size_type __n)
+{
+    _ConstructTransaction __tx(&this->__end_, __n);
+    for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_) {
+        __alloc_traits::construct(this->__alloc(), _VSTD::__to_address(__tx.__pos_));
+    }
+}
+
+//  Copy constructs __n objects starting at __end_ from __x
+//  throws if construction throws
+//  Precondition:  __n > 0
+//  Precondition:  size() + __n <= capacity()
+//  Postcondition:  size() == old size() + __n
+//  Postcondition:  [i] == __x for all i in [size() - __n, __n)
+template <class _Tp, class _Allocator>
+void
+__split_buffer<_Tp, _Allocator>::__construct_at_end(size_type __n, const_reference __x)
+{
+    _ConstructTransaction __tx(&this->__end_, __n);
+    for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_) {
+        __alloc_traits::construct(this->__alloc(),
+            _VSTD::__to_address(__tx.__pos_), __x);
+    }
+}
+
+template <class _Tp, class _Allocator>
+template <class _InputIter>
+typename enable_if
+<
+     __is_cpp17_input_iterator<_InputIter>::value &&
+    !__is_cpp17_forward_iterator<_InputIter>::value,
+    void
+>::type
+__split_buffer<_Tp, _Allocator>::__construct_at_end(_InputIter __first, _InputIter __last)
+{
+    __alloc_rr& __a = this->__alloc();
+    for (; __first != __last; ++__first)
+    {
+        if (__end_ == __end_cap())
+        {
+            size_type __old_cap = __end_cap() - __first_;
+            size_type __new_cap = _VSTD::max<size_type>(2 * __old_cap, 8);
+            __split_buffer __buf(__new_cap, 0, __a);
+            for (pointer __p = __begin_; __p != __end_; ++__p, (void) ++__buf.__end_)
+                __alloc_traits::construct(__buf.__alloc(),
+                        _VSTD::__to_address(__buf.__end_), _VSTD::move(*__p));
+            swap(__buf);
+        }
+        __alloc_traits::construct(__a, _VSTD::__to_address(this->__end_), *__first);
+        ++this->__end_;
+    }
+}
+
+template <class _Tp, class _Allocator>
+template <class _ForwardIterator>
+typename enable_if
+<
+    __is_cpp17_forward_iterator<_ForwardIterator>::value,
+    void
+>::type
+__split_buffer<_Tp, _Allocator>::__construct_at_end(_ForwardIterator __first, _ForwardIterator __last)
+{
+    _ConstructTransaction __tx(&this->__end_, _VSTD::distance(__first, __last));
+    for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_, (void) ++__first) {
+        __alloc_traits::construct(this->__alloc(),
+            _VSTD::__to_address(__tx.__pos_), *__first);
+    }
+}
+
+template <class _Tp, class _Allocator>
+inline
+void
+__split_buffer<_Tp, _Allocator>::__destruct_at_begin(pointer __new_begin, false_type)
+{
+    while (__begin_ != __new_begin)
+        __alloc_traits::destroy(__alloc(), _VSTD::__to_address(__begin_++));
+}
+
+template <class _Tp, class _Allocator>
+inline
+void
+__split_buffer<_Tp, _Allocator>::__destruct_at_begin(pointer __new_begin, true_type)
+{
+    __begin_ = __new_begin;
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+__split_buffer<_Tp, _Allocator>::__destruct_at_end(pointer __new_last, false_type) _NOEXCEPT
+{
+    while (__new_last != __end_)
+        __alloc_traits::destroy(__alloc(), _VSTD::__to_address(--__end_));
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+__split_buffer<_Tp, _Allocator>::__destruct_at_end(pointer __new_last, true_type) _NOEXCEPT
+{
+    __end_ = __new_last;
+}
+
+template <class _Tp, class _Allocator>
+__split_buffer<_Tp, _Allocator>::__split_buffer(size_type __cap, size_type __start, __alloc_rr& __a)
+    : __end_cap_(nullptr, __a)
+{
+    __first_ = __cap != 0 ? __alloc_traits::allocate(__alloc(), __cap) : nullptr;
+    __begin_ = __end_ = __first_ + __start;
+    __end_cap() = __first_ + __cap;
+}
+
+template <class _Tp, class _Allocator>
+inline
+__split_buffer<_Tp, _Allocator>::__split_buffer()
+    _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
+    : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __default_init_tag())
+{
+}
+
+template <class _Tp, class _Allocator>
+inline
+__split_buffer<_Tp, _Allocator>::__split_buffer(__alloc_rr& __a)
+    : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __a)
+{
+}
+
+template <class _Tp, class _Allocator>
+inline
+__split_buffer<_Tp, _Allocator>::__split_buffer(const __alloc_rr& __a)
+    : __first_(nullptr), __begin_(nullptr), __end_(nullptr), __end_cap_(nullptr, __a)
+{
+}
+
+template <class _Tp, class _Allocator>
+__split_buffer<_Tp, _Allocator>::~__split_buffer()
+{
+    clear();
+    if (__first_)
+        __alloc_traits::deallocate(__alloc(), __first_, capacity());
+}
+
+template <class _Tp, class _Allocator>
+__split_buffer<_Tp, _Allocator>::__split_buffer(__split_buffer&& __c)
+    _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
+    : __first_(_VSTD::move(__c.__first_)),
+      __begin_(_VSTD::move(__c.__begin_)),
+      __end_(_VSTD::move(__c.__end_)),
+      __end_cap_(_VSTD::move(__c.__end_cap_))
+{
+    __c.__first_ = nullptr;
+    __c.__begin_ = nullptr;
+    __c.__end_ = nullptr;
+    __c.__end_cap() = nullptr;
+}
+
+template <class _Tp, class _Allocator>
+__split_buffer<_Tp, _Allocator>::__split_buffer(__split_buffer&& __c, const __alloc_rr& __a)
+    : __end_cap_(nullptr, __a)
+{
+    if (__a == __c.__alloc())
+    {
+        __first_ = __c.__first_;
+        __begin_ = __c.__begin_;
+        __end_ = __c.__end_;
+        __end_cap() = __c.__end_cap();
+        __c.__first_ = nullptr;
+        __c.__begin_ = nullptr;
+        __c.__end_ = nullptr;
+        __c.__end_cap() = nullptr;
+    }
+    else
+    {
+        size_type __cap = __c.size();
+        __first_ = __alloc_traits::allocate(__alloc(), __cap);
+        __begin_ = __end_ = __first_;
+        __end_cap() = __first_ + __cap;
+        typedef move_iterator<iterator> _Ip;
+        __construct_at_end(_Ip(__c.begin()), _Ip(__c.end()));
+    }
+}
+
+template <class _Tp, class _Allocator>
+__split_buffer<_Tp, _Allocator>&
+__split_buffer<_Tp, _Allocator>::operator=(__split_buffer&& __c)
+    _NOEXCEPT_((__alloc_traits::propagate_on_container_move_assignment::value &&
+                is_nothrow_move_assignable<allocator_type>::value) ||
+               !__alloc_traits::propagate_on_container_move_assignment::value)
+{
+    clear();
+    shrink_to_fit();
+    __first_ = __c.__first_;
+    __begin_ = __c.__begin_;
+    __end_ = __c.__end_;
+    __end_cap() = __c.__end_cap();
+    __move_assign_alloc(__c,
+        integral_constant<bool,
+                          __alloc_traits::propagate_on_container_move_assignment::value>());
+    __c.__first_ = __c.__begin_ = __c.__end_ = __c.__end_cap() = nullptr;
+    return *this;
+}
+
+template <class _Tp, class _Allocator>
+void
+__split_buffer<_Tp, _Allocator>::swap(__split_buffer& __x)
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value||
+                   __is_nothrow_swappable<__alloc_rr>::value)
+{
+    _VSTD::swap(__first_, __x.__first_);
+    _VSTD::swap(__begin_, __x.__begin_);
+    _VSTD::swap(__end_, __x.__end_);
+    _VSTD::swap(__end_cap(), __x.__end_cap());
+    _VSTD::__swap_allocator(__alloc(), __x.__alloc());
+}
+
+template <class _Tp, class _Allocator>
+void
+__split_buffer<_Tp, _Allocator>::reserve(size_type __n)
+{
+    if (__n < capacity())
+    {
+        __split_buffer<value_type, __alloc_rr&> __t(__n, 0, __alloc());
+        __t.__construct_at_end(move_iterator<pointer>(__begin_),
+                               move_iterator<pointer>(__end_));
+        _VSTD::swap(__first_, __t.__first_);
+        _VSTD::swap(__begin_, __t.__begin_);
+        _VSTD::swap(__end_, __t.__end_);
+        _VSTD::swap(__end_cap(), __t.__end_cap());
+    }
+}
+
+template <class _Tp, class _Allocator>
+void
+__split_buffer<_Tp, _Allocator>::shrink_to_fit() _NOEXCEPT
+{
+    if (capacity() > size())
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            __split_buffer<value_type, __alloc_rr&> __t(size(), 0, __alloc());
+            __t.__construct_at_end(move_iterator<pointer>(__begin_),
+                                   move_iterator<pointer>(__end_));
+            __t.__end_ = __t.__begin_ + (__end_ - __begin_);
+            _VSTD::swap(__first_, __t.__first_);
+            _VSTD::swap(__begin_, __t.__begin_);
+            _VSTD::swap(__end_, __t.__end_);
+            _VSTD::swap(__end_cap(), __t.__end_cap());
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+}
+
+template <class _Tp, class _Allocator>
+void
+__split_buffer<_Tp, _Allocator>::push_front(const_reference __x)
+{
+    if (__begin_ == __first_)
+    {
+        if (__end_ < __end_cap())
+        {
+            difference_type __d = __end_cap() - __end_;
+            __d = (__d + 1) / 2;
+            __begin_ = _VSTD::move_backward(__begin_, __end_, __end_ + __d);
+            __end_ += __d;
+        }
+        else
+        {
+            size_type __c = max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1);
+            __split_buffer<value_type, __alloc_rr&> __t(__c, (__c + 3) / 4, __alloc());
+            __t.__construct_at_end(move_iterator<pointer>(__begin_),
+                                   move_iterator<pointer>(__end_));
+            _VSTD::swap(__first_, __t.__first_);
+            _VSTD::swap(__begin_, __t.__begin_);
+            _VSTD::swap(__end_, __t.__end_);
+            _VSTD::swap(__end_cap(), __t.__end_cap());
+        }
+    }
+    __alloc_traits::construct(__alloc(), _VSTD::__to_address(__begin_-1), __x);
+    --__begin_;
+}
+
+template <class _Tp, class _Allocator>
+void
+__split_buffer<_Tp, _Allocator>::push_front(value_type&& __x)
+{
+    if (__begin_ == __first_)
+    {
+        if (__end_ < __end_cap())
+        {
+            difference_type __d = __end_cap() - __end_;
+            __d = (__d + 1) / 2;
+            __begin_ = _VSTD::move_backward(__begin_, __end_, __end_ + __d);
+            __end_ += __d;
+        }
+        else
+        {
+            size_type __c = max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1);
+            __split_buffer<value_type, __alloc_rr&> __t(__c, (__c + 3) / 4, __alloc());
+            __t.__construct_at_end(move_iterator<pointer>(__begin_),
+                                   move_iterator<pointer>(__end_));
+            _VSTD::swap(__first_, __t.__first_);
+            _VSTD::swap(__begin_, __t.__begin_);
+            _VSTD::swap(__end_, __t.__end_);
+            _VSTD::swap(__end_cap(), __t.__end_cap());
+        }
+    }
+    __alloc_traits::construct(__alloc(), _VSTD::__to_address(__begin_-1),
+            _VSTD::move(__x));
+    --__begin_;
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+__split_buffer<_Tp, _Allocator>::push_back(const_reference __x)
+{
+    if (__end_ == __end_cap())
+    {
+        if (__begin_ > __first_)
+        {
+            difference_type __d = __begin_ - __first_;
+            __d = (__d + 1) / 2;
+            __end_ = _VSTD::move(__begin_, __end_, __begin_ - __d);
+            __begin_ -= __d;
+        }
+        else
+        {
+            size_type __c = max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1);
+            __split_buffer<value_type, __alloc_rr&> __t(__c, __c / 4, __alloc());
+            __t.__construct_at_end(move_iterator<pointer>(__begin_),
+                                   move_iterator<pointer>(__end_));
+            _VSTD::swap(__first_, __t.__first_);
+            _VSTD::swap(__begin_, __t.__begin_);
+            _VSTD::swap(__end_, __t.__end_);
+            _VSTD::swap(__end_cap(), __t.__end_cap());
+        }
+    }
+    __alloc_traits::construct(__alloc(), _VSTD::__to_address(__end_), __x);
+    ++__end_;
+}
+
+template <class _Tp, class _Allocator>
+void
+__split_buffer<_Tp, _Allocator>::push_back(value_type&& __x)
+{
+    if (__end_ == __end_cap())
+    {
+        if (__begin_ > __first_)
+        {
+            difference_type __d = __begin_ - __first_;
+            __d = (__d + 1) / 2;
+            __end_ = _VSTD::move(__begin_, __end_, __begin_ - __d);
+            __begin_ -= __d;
+        }
+        else
+        {
+            size_type __c = max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1);
+            __split_buffer<value_type, __alloc_rr&> __t(__c, __c / 4, __alloc());
+            __t.__construct_at_end(move_iterator<pointer>(__begin_),
+                                   move_iterator<pointer>(__end_));
+            _VSTD::swap(__first_, __t.__first_);
+            _VSTD::swap(__begin_, __t.__begin_);
+            _VSTD::swap(__end_, __t.__end_);
+            _VSTD::swap(__end_cap(), __t.__end_cap());
+        }
+    }
+    __alloc_traits::construct(__alloc(), _VSTD::__to_address(__end_),
+            _VSTD::move(__x));
+    ++__end_;
+}
+
+template <class _Tp, class _Allocator>
+template <class... _Args>
+void
+__split_buffer<_Tp, _Allocator>::emplace_back(_Args&&... __args)
+{
+    if (__end_ == __end_cap())
+    {
+        if (__begin_ > __first_)
+        {
+            difference_type __d = __begin_ - __first_;
+            __d = (__d + 1) / 2;
+            __end_ = _VSTD::move(__begin_, __end_, __begin_ - __d);
+            __begin_ -= __d;
+        }
+        else
+        {
+            size_type __c = max<size_type>(2 * static_cast<size_t>(__end_cap() - __first_), 1);
+            __split_buffer<value_type, __alloc_rr&> __t(__c, __c / 4, __alloc());
+            __t.__construct_at_end(move_iterator<pointer>(__begin_),
+                                   move_iterator<pointer>(__end_));
+            _VSTD::swap(__first_, __t.__first_);
+            _VSTD::swap(__begin_, __t.__begin_);
+            _VSTD::swap(__end_, __t.__end_);
+            _VSTD::swap(__end_cap(), __t.__end_cap());
+        }
+    }
+    __alloc_traits::construct(__alloc(), _VSTD::__to_address(__end_),
+                              _VSTD::forward<_Args>(__args)...);
+    ++__end_;
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(__split_buffer<_Tp, _Allocator>& __x, __split_buffer<_Tp, _Allocator>& __y)
+        _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_SPLIT_BUFFER
diff --git a/contrib/libs/cxxsupp/libcxx/include/__std_stream b/contrib/libs/cxxsupp/libcxx/include/__std_stream
new file mode 100644
index 00000000000..65e90b7894b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__std_stream
@@ -0,0 +1,361 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___STD_STREAM
+#define _LIBCPP___STD_STREAM
+
+#include <__config>
+#include <__locale>
+#include <cstdio>
+#include <istream>
+#include <ostream>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+static const int __limit = 8;
+
+// __stdinbuf
+
+template <class _CharT>
+class _LIBCPP_HIDDEN __stdinbuf
+    : public basic_streambuf<_CharT, char_traits<_CharT> >
+{
+public:
+    typedef _CharT                           char_type;
+    typedef char_traits<char_type>           traits_type;
+    typedef typename traits_type::int_type   int_type;
+    typedef typename traits_type::pos_type   pos_type;
+    typedef typename traits_type::off_type   off_type;
+    typedef typename traits_type::state_type state_type;
+
+    __stdinbuf(FILE* __fp, state_type* __st);
+
+protected:
+    virtual int_type underflow();
+    virtual int_type uflow();
+    virtual int_type pbackfail(int_type __c = traits_type::eof());
+    virtual void imbue(const locale& __loc);
+
+private:
+
+    FILE* __file_;
+    const codecvt<char_type, char, state_type>* __cv_;
+    state_type* __st_;
+    int __encoding_;
+    int_type __last_consumed_;
+    bool __last_consumed_is_next_;
+    bool __always_noconv_;
+
+    __stdinbuf(const __stdinbuf&);
+    __stdinbuf& operator=(const __stdinbuf&);
+
+    int_type __getchar(bool __consume);
+};
+
+template <class _CharT>
+__stdinbuf<_CharT>::__stdinbuf(FILE* __fp, state_type* __st)
+    : __file_(__fp),
+      __st_(__st),
+      __last_consumed_(traits_type::eof()),
+      __last_consumed_is_next_(false)
+{
+    imbue(this->getloc());
+}
+
+template <class _CharT>
+void
+__stdinbuf<_CharT>::imbue(const locale& __loc)
+{
+    __cv_ = &use_facet<codecvt<char_type, char, state_type> >(__loc);
+    __encoding_ = __cv_->encoding();
+    __always_noconv_ = __cv_->always_noconv();
+    if (__encoding_ > __limit)
+        __throw_runtime_error("unsupported locale for standard input");
+}
+
+template <class _CharT>
+typename __stdinbuf<_CharT>::int_type
+__stdinbuf<_CharT>::underflow()
+{
+    return __getchar(false);
+}
+
+template <class _CharT>
+typename __stdinbuf<_CharT>::int_type
+__stdinbuf<_CharT>::uflow()
+{
+    return __getchar(true);
+}
+
+template <class _CharT>
+typename __stdinbuf<_CharT>::int_type
+__stdinbuf<_CharT>::__getchar(bool __consume)
+{
+    if (__last_consumed_is_next_)
+    {
+        int_type __result = __last_consumed_;
+        if (__consume)
+        {
+            __last_consumed_ = traits_type::eof();
+            __last_consumed_is_next_ = false;
+        }
+        return __result;
+    }
+    char __extbuf[__limit];
+    int __nread = _VSTD::max(1, __encoding_);
+    for (int __i = 0; __i < __nread; ++__i)
+    {
+        int __c = getc(__file_);
+        if (__c == EOF)
+            return traits_type::eof();
+        __extbuf[__i] = static_cast<char>(__c);
+    }
+    char_type __1buf;
+    if (__always_noconv_)
+        __1buf = static_cast<char_type>(__extbuf[0]);
+    else
+    {
+        const char* __enxt;
+        char_type* __inxt;
+        codecvt_base::result __r;
+        do
+        {
+            state_type __sv_st = *__st_;
+            __r = __cv_->in(*__st_, __extbuf, __extbuf + __nread, __enxt,
+                                   &__1buf, &__1buf + 1, __inxt);
+            switch (__r)
+            {
+            case _VSTD::codecvt_base::ok:
+                break;
+            case codecvt_base::partial:
+                *__st_ = __sv_st;
+                if (__nread == sizeof(__extbuf))
+                    return traits_type::eof();
+                {
+                    int __c = getc(__file_);
+                    if (__c == EOF)
+                        return traits_type::eof();
+                    __extbuf[__nread] = static_cast<char>(__c);
+                }
+                ++__nread;
+                break;
+            case codecvt_base::error:
+                return traits_type::eof();
+            case _VSTD::codecvt_base::noconv:
+                __1buf = static_cast<char_type>(__extbuf[0]);
+                break;
+            }
+        } while (__r == _VSTD::codecvt_base::partial);
+    }
+    if (!__consume)
+    {
+        for (int __i = __nread; __i > 0;)
+        {
+            if (ungetc(traits_type::to_int_type(__extbuf[--__i]), __file_) == EOF)
+                return traits_type::eof();
+        }
+    }
+    else
+        __last_consumed_ = traits_type::to_int_type(__1buf);
+    return traits_type::to_int_type(__1buf);
+}
+
+template <class _CharT>
+typename __stdinbuf<_CharT>::int_type
+__stdinbuf<_CharT>::pbackfail(int_type __c)
+{
+    if (traits_type::eq_int_type(__c, traits_type::eof()))
+    {
+        if (!__last_consumed_is_next_)
+        {
+            __c = __last_consumed_;
+            __last_consumed_is_next_ = !traits_type::eq_int_type(__last_consumed_,
+                                                                 traits_type::eof());
+        }
+        return __c;
+    }
+    if (__last_consumed_is_next_)
+    {
+        char __extbuf[__limit];
+        char* __enxt;
+        const char_type __ci = traits_type::to_char_type(__last_consumed_);
+        const char_type* __inxt;
+        switch (__cv_->out(*__st_, &__ci, &__ci + 1, __inxt,
+                                  __extbuf, __extbuf + sizeof(__extbuf), __enxt))
+        {
+        case _VSTD::codecvt_base::ok:
+            break;
+        case _VSTD::codecvt_base::noconv:
+            __extbuf[0] = static_cast<char>(__last_consumed_);
+            __enxt = __extbuf + 1;
+            break;
+        case codecvt_base::partial:
+        case codecvt_base::error:
+            return traits_type::eof();
+        }
+        while (__enxt > __extbuf)
+            if (ungetc(*--__enxt, __file_) == EOF)
+                return traits_type::eof();
+    }
+    __last_consumed_ = __c;
+    __last_consumed_is_next_ = true;
+    return __c;
+}
+
+// __stdoutbuf
+
+template <class _CharT>
+class _LIBCPP_HIDDEN __stdoutbuf
+    : public basic_streambuf<_CharT, char_traits<_CharT> >
+{
+public:
+    typedef _CharT                           char_type;
+    typedef char_traits<char_type>           traits_type;
+    typedef typename traits_type::int_type   int_type;
+    typedef typename traits_type::pos_type   pos_type;
+    typedef typename traits_type::off_type   off_type;
+    typedef typename traits_type::state_type state_type;
+
+    __stdoutbuf(FILE* __fp, state_type* __st);
+
+protected:
+    virtual int_type overflow (int_type __c = traits_type::eof());
+    virtual streamsize xsputn(const char_type* __s, streamsize __n);
+    virtual int sync();
+    virtual void imbue(const locale& __loc);
+
+private:
+    FILE* __file_;
+    const codecvt<char_type, char, state_type>* __cv_;
+    state_type* __st_;
+    bool __always_noconv_;
+
+    __stdoutbuf(const __stdoutbuf&);
+    __stdoutbuf& operator=(const __stdoutbuf&);
+};
+
+template <class _CharT>
+__stdoutbuf<_CharT>::__stdoutbuf(FILE* __fp, state_type* __st)
+    : __file_(__fp),
+      __cv_(&use_facet<codecvt<char_type, char, state_type> >(this->getloc())),
+      __st_(__st),
+      __always_noconv_(__cv_->always_noconv())
+{
+}
+
+template <class _CharT>
+typename __stdoutbuf<_CharT>::int_type
+__stdoutbuf<_CharT>::overflow(int_type __c)
+{
+    char __extbuf[__limit];
+    char_type __1buf;
+    if (!traits_type::eq_int_type(__c, traits_type::eof()))
+    {
+        __1buf = traits_type::to_char_type(__c);
+        if (__always_noconv_)
+        {
+            if (fwrite(&__1buf, sizeof(char_type), 1, __file_) != 1)
+                return traits_type::eof();
+        }
+        else
+        {
+            char* __extbe = __extbuf;
+            codecvt_base::result __r;
+            char_type* pbase = &__1buf;
+            char_type* pptr = pbase + 1;
+            do
+            {
+                const char_type* __e;
+                __r = __cv_->out(*__st_, pbase, pptr, __e,
+                                        __extbuf,
+                                        __extbuf + sizeof(__extbuf),
+                                        __extbe);
+                if (__e == pbase)
+                    return traits_type::eof();
+                if (__r == codecvt_base::noconv)
+                {
+                    if (fwrite(pbase, 1, 1, __file_) != 1)
+                        return traits_type::eof();
+                }
+                else if (__r == codecvt_base::ok || __r == codecvt_base::partial)
+                {
+                    size_t __nmemb = static_cast<size_t>(__extbe - __extbuf);
+                    if (fwrite(__extbuf, 1, __nmemb, __file_) != __nmemb)
+                        return traits_type::eof();
+                    if (__r == codecvt_base::partial)
+                    {
+                        pbase = const_cast<char_type*>(__e);
+                    }
+                }
+                else
+                    return traits_type::eof();
+            } while (__r == codecvt_base::partial);
+        }
+    }
+    return traits_type::not_eof(__c);
+}
+
+template <class _CharT>
+streamsize
+__stdoutbuf<_CharT>::xsputn(const char_type* __s, streamsize __n)
+{
+    if (__always_noconv_)
+        return fwrite(__s, sizeof(char_type), __n, __file_);
+    streamsize __i = 0;
+    for (; __i < __n; ++__i, ++__s)
+        if (overflow(traits_type::to_int_type(*__s)) == traits_type::eof())
+            break;
+    return __i;
+}
+
+template <class _CharT>
+int
+__stdoutbuf<_CharT>::sync()
+{
+    char __extbuf[__limit];
+    codecvt_base::result __r;
+    do
+    {
+        char* __extbe;
+        __r = __cv_->unshift(*__st_, __extbuf,
+                                    __extbuf + sizeof(__extbuf),
+                                    __extbe);
+        size_t __nmemb = static_cast<size_t>(__extbe - __extbuf);
+        if (fwrite(__extbuf, 1, __nmemb, __file_) != __nmemb)
+            return -1;
+    } while (__r == codecvt_base::partial);
+    if (__r == codecvt_base::error)
+        return -1;
+    if (fflush(__file_))
+        return -1;
+    return 0;
+}
+
+template <class _CharT>
+void
+__stdoutbuf<_CharT>::imbue(const locale& __loc)
+{
+    sync();
+    __cv_ = &use_facet<codecvt<char_type, char, state_type> >(__loc);
+    __always_noconv_ = __cv_->always_noconv();
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___STD_STREAM
diff --git a/contrib/libs/cxxsupp/libcxx/include/__string b/contrib/libs/cxxsupp/libcxx/include/__string
new file mode 100644
index 00000000000..7074a735386
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__string
@@ -0,0 +1,1187 @@
+// -*- C++ -*-
+//===-------------------------- __string ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___STRING
+#define _LIBCPP___STRING
+
+#include <__config>
+#include <__algorithm/copy.h>
+#include <__algorithm/copy_backward.h>
+#include <__algorithm/copy_n.h>
+#include <__algorithm/fill_n.h>
+#include <__algorithm/find_first_of.h>
+#include <__algorithm/find_end.h>
+#include <__algorithm/min.h>
+#include <__functional/hash.h>     // for __murmur2_or_cityhash
+#include <__iterator/iterator_traits.h>
+#include <cstdio>      // for EOF
+#include <cstdint>     // for uint_least16_t
+#include <cstring>     // for memcpy
+#include <type_traits> // for __libcpp_is_constant_evaluated
+#include <iosfwd>      // for streampos & friends
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#   include <cwchar> // for wmemcpy
+#endif
+
+#include <__debug>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// The the extern template ABI lists are kept outside of <string> to improve the
+// readability of that header.
+
+// The extern template ABI lists are kept outside of <string> to improve the
+// readability of that header. We maintain 2 ABI lists:
+// - _LIBCPP_STRING_V1_EXTERN_TEMPLATE_LIST
+// - _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST
+// As the name implies, the ABI lists define the V1 (Stable) and unstable ABI.
+//
+// For unstable, we may explicitly remove function that are external in V1,
+// and add (new) external functions to better control inlining and compiler
+// optimization opportunities.
+//
+// For stable, the ABI list should rarely change, except for adding new
+// functions supporting new c++ version / API changes. Typically entries
+// must never be removed from the stable list.
+#define _LIBCPP_STRING_V1_EXTERN_TEMPLATE_LIST(_Func, _CharType) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::replace(size_type, size_type, value_type const*, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::rfind(value_type const*, size_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__init(value_type const*, size_type, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::basic_string(basic_string const&)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::replace(size_type, size_type, value_type const*)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::basic_string(basic_string const&, allocator<_CharType> const&)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find_last_not_of(value_type const*, size_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::~basic_string()) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find_first_not_of(value_type const*, size_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::insert(size_type, size_type, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::operator=(value_type)) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__init(value_type const*, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS const _CharType& basic_string<_CharType>::at(size_type) const) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::insert(size_type, value_type const*, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find_first_of(value_type const*, size_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::replace(size_type, size_type, size_type, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::assign(value_type const*, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::reserve(size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::append(value_type const*, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::assign(basic_string const&, size_type, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::copy(value_type*, size_type, size_type) const) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::basic_string(basic_string const&, size_type, size_type, allocator<_CharType> const&)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find(value_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__init(size_type, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::insert(size_type, value_type const*)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find_last_of(value_type const*, size_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__grow_by(size_type, size_type, size_type, size_type, size_type, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__grow_by_and_replace(size_type, size_type, size_type, size_type, size_type, size_type, value_type const*)) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::push_back(value_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::append(size_type, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::rfind(value_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::assign(size_type, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::erase(size_type, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::append(basic_string const&, size_type, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS int basic_string<_CharType>::compare(value_type const*) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS int basic_string<_CharType>::compare(size_type, size_type, value_type const*) const) \
+  _Func(_LIBCPP_FUNC_VIS _CharType& basic_string<_CharType>::at(size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::assign(value_type const*)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find(value_type const*, size_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS int basic_string<_CharType>::compare(size_type, size_type, basic_string const&, size_type, size_type) const) \
+  _Func(_LIBCPP_FUNC_VIS int basic_string<_CharType>::compare(size_type, size_type, value_type const*, size_type) const) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::operator=(basic_string const&)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::append(value_type const*)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::replace(size_type, size_type, basic_string const&, size_type, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::iterator basic_string<_CharType>::insert(basic_string::const_iterator, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::resize(size_type, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::insert(size_type, basic_string const&, size_type, size_type)) \
+  _LIBCPP_STRING_EXTERN_TEMPLATE_VARIABLE_LIST(_Func, _CharType)
+
+#define _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_Func, _CharType) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::replace(size_type, size_type, value_type const*, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::rfind(value_type const*, size_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__init(value_type const*, size_type, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::replace(size_type, size_type, value_type const*)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find_last_not_of(value_type const*, size_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::~basic_string()) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find_first_not_of(value_type const*, size_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::insert(size_type, size_type, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::operator=(value_type)) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__init(value_type const*, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__init_copy_ctor_external(value_type const*, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS const _CharType& basic_string<_CharType>::at(size_type) const) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::insert(size_type, value_type const*, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find_first_of(value_type const*, size_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::replace(size_type, size_type, size_type, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::__assign_external(value_type const*, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::__assign_external(value_type const*)) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::reserve(size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::append(value_type const*, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::assign(basic_string const&, size_type, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::copy(value_type*, size_type, size_type) const) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::basic_string(basic_string const&, size_type, size_type, allocator<_CharType> const&)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find(value_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__init(size_type, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::insert(size_type, value_type const*)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find_last_of(value_type const*, size_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__grow_by(size_type, size_type, size_type, size_type, size_type, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__grow_by_and_replace(size_type, size_type, size_type, size_type, size_type, size_type, value_type const*)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::__assign_no_alias<false>(value_type const*, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::__assign_no_alias<true>(value_type const*, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::push_back(value_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::append(size_type, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::rfind(value_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::assign(size_type, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::__erase_external_with_move(size_type, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::append(basic_string const&, size_type, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS int basic_string<_CharType>::compare(value_type const*) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS int basic_string<_CharType>::compare(size_type, size_type, value_type const*) const) \
+  _Func(_LIBCPP_FUNC_VIS _CharType& basic_string<_CharType>::at(size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::size_type basic_string<_CharType>::find(value_type const*, size_type, size_type) const _NOEXCEPT) \
+  _Func(_LIBCPP_FUNC_VIS int basic_string<_CharType>::compare(size_type, size_type, basic_string const&, size_type, size_type) const) \
+  _Func(_LIBCPP_FUNC_VIS int basic_string<_CharType>::compare(size_type, size_type, value_type const*, size_type) const) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::append(value_type const*)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::replace(size_type, size_type, basic_string const&, size_type, size_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::iterator basic_string<_CharType>::insert(basic_string::const_iterator, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS void basic_string<_CharType>::resize(size_type, value_type)) \
+  _Func(_LIBCPP_FUNC_VIS basic_string<_CharType>& basic_string<_CharType>::insert(size_type, basic_string const&, size_type, size_type)) \
+  _LIBCPP_STRING_EXTERN_TEMPLATE_VARIABLE_LIST(_Func, _CharType)
+
+// Workaround for CUDA which doesn't like extern templates for variables.
+#ifdef __CUDACC__
+#define _LIBCPP_STRING_EXTERN_TEMPLATE_VARIABLE_LIST(_Func, _CharType)
+#else
+#define _LIBCPP_STRING_EXTERN_TEMPLATE_VARIABLE_LIST(_Func, _CharType) \
+  _Func(_LIBCPP_FUNC_VIS const basic_string<_CharType>::size_type basic_string<_CharType>::npos)
+#endif
+
+// char_traits
+
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS char_traits
+{
+    typedef _CharT    char_type;
+    typedef int       int_type;
+    typedef streamoff off_type;
+    typedef streampos pos_type;
+    typedef mbstate_t state_type;
+
+    static inline void _LIBCPP_CONSTEXPR_AFTER_CXX14
+        assign(char_type& __c1, const char_type& __c2) _NOEXCEPT {__c1 = __c2;}
+    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
+        {return __c1 == __c2;}
+    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
+        {return __c1 < __c2;}
+
+    static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    int compare(const char_type* __s1, const char_type* __s2, size_t __n);
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    size_t length(const char_type* __s);
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const char_type* find(const char_type* __s, size_t __n, const char_type& __a);
+    static _LIBCPP_CONSTEXPR_AFTER_CXX17
+    char_type*       move(char_type* __s1, const char_type* __s2, size_t __n);
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR_AFTER_CXX17
+    char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n);
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR_AFTER_CXX17
+    char_type*       assign(char_type* __s, size_t __n, char_type __a);
+
+    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
+        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
+    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
+        {return char_type(__c);}
+    static inline _LIBCPP_CONSTEXPR int_type  to_int_type(char_type __c) _NOEXCEPT
+        {return int_type(__c);}
+    static inline _LIBCPP_CONSTEXPR bool      eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
+        {return __c1 == __c2;}
+    static inline _LIBCPP_CONSTEXPR int_type  eof() _NOEXCEPT
+        {return int_type(EOF);}
+};
+
+template <class _CharT>
+_LIBCPP_CONSTEXPR_AFTER_CXX14 int
+char_traits<_CharT>::compare(const char_type* __s1, const char_type* __s2, size_t __n)
+{
+    for (; __n; --__n, ++__s1, ++__s2)
+    {
+        if (lt(*__s1, *__s2))
+            return -1;
+        if (lt(*__s2, *__s1))
+            return 1;
+    }
+    return 0;
+}
+
+template <class _CharT>
+inline
+_LIBCPP_CONSTEXPR_AFTER_CXX14 size_t
+char_traits<_CharT>::length(const char_type* __s)
+{
+    size_t __len = 0;
+    for (; !eq(*__s, char_type(0)); ++__s)
+        ++__len;
+    return __len;
+}
+
+template <class _CharT>
+inline
+_LIBCPP_CONSTEXPR_AFTER_CXX14 const _CharT*
+char_traits<_CharT>::find(const char_type* __s, size_t __n, const char_type& __a)
+{
+    for (; __n; --__n)
+    {
+        if (eq(*__s, __a))
+            return __s;
+        ++__s;
+    }
+    return nullptr;
+}
+
+template <class _CharT>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 _CharT*
+char_traits<_CharT>::move(char_type* __s1, const char_type* __s2, size_t __n)
+{
+    if (__n == 0) return __s1;
+    char_type* __r = __s1;
+    if (__s1 < __s2)
+    {
+        for (; __n; --__n, ++__s1, ++__s2)
+            assign(*__s1, *__s2);
+    }
+    else if (__s2 < __s1)
+    {
+        __s1 += __n;
+        __s2 += __n;
+        for (; __n; --__n)
+            assign(*--__s1, *--__s2);
+    }
+    return __r;
+}
+
+template <class _CharT>
+inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+_CharT*
+char_traits<_CharT>::copy(char_type* __s1, const char_type* __s2, size_t __n)
+{
+    if (!__libcpp_is_constant_evaluated()) {
+        _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
+    }
+    char_type* __r = __s1;
+    for (; __n; --__n, ++__s1, ++__s2)
+        assign(*__s1, *__s2);
+    return __r;
+}
+
+template <class _CharT>
+inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+_CharT*
+char_traits<_CharT>::assign(char_type* __s, size_t __n, char_type __a)
+{
+    char_type* __r = __s;
+    for (; __n; --__n, ++__s)
+        assign(*__s, __a);
+    return __r;
+}
+
+// constexpr versions of move/copy/assign.
+
+template <class _CharT>
+static inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+_CharT* __move_constexpr(_CharT* __s1, const _CharT* __s2, size_t __n) _NOEXCEPT
+{
+    if (__n == 0) return __s1;
+    if (__s1 < __s2) {
+      _VSTD::copy(__s2, __s2 + __n, __s1);
+    } else if (__s2 < __s1) {
+      _VSTD::copy_backward(__s2, __s2 + __n, __s1 + __n);
+    }
+    return __s1;
+}
+
+template <class _CharT>
+static inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+_CharT* __copy_constexpr(_CharT* __s1, const _CharT* __s2, size_t __n) _NOEXCEPT
+{
+    _VSTD::copy_n(__s2, __n, __s1);
+    return __s1;
+}
+
+template <class _CharT>
+static inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+_CharT* __assign_constexpr(_CharT* __s, size_t __n, _CharT __a) _NOEXCEPT
+{
+     _VSTD::fill_n(__s, __n, __a);
+     return __s;
+}
+
+// char_traits<char>
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS char_traits<char>
+{
+    typedef char      char_type;
+    typedef int       int_type;
+    typedef streamoff off_type;
+    typedef streampos pos_type;
+    typedef mbstate_t state_type;
+
+    static inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+    void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT {__c1 = __c2;}
+    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
+            {return __c1 == __c2;}
+    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
+        {return (unsigned char)__c1 < (unsigned char)__c2;}
+
+    static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    int compare(const char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT;
+#ifdef _LIBCPP_COMPILER_MSVC
+    static inline size_t _LIBCPP_CONSTEXPR_AFTER_CXX14 length(const char_type* __s)  _NOEXCEPT
+        {
+            size_t __len = 0;
+            for (; !eq(*__s, char_type(0)); ++__s)
+                ++__len;
+            return __len;
+        }
+#else
+    static inline size_t _LIBCPP_CONSTEXPR_AFTER_CXX14
+    length(const char_type* __s)  _NOEXCEPT {return __builtin_strlen(__s);}
+#endif
+    static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const char_type* find(const char_type* __s, size_t __n, const char_type& __a) _NOEXCEPT;
+    static inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+    char_type* move(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+        {
+            return __libcpp_is_constant_evaluated()
+                       ? _VSTD::__move_constexpr(__s1, __s2, __n)
+                       : __n == 0 ? __s1 : (char_type*)_VSTD::memmove(__s1, __s2, __n);
+        }
+    static inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+    char_type* copy(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+        {
+            if (!__libcpp_is_constant_evaluated()) {
+                _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
+            }
+            return __libcpp_is_constant_evaluated()
+                       ? _VSTD::__copy_constexpr(__s1, __s2, __n)
+                       : __n == 0 ? __s1 : (char_type*)_VSTD::memcpy(__s1, __s2, __n);
+        }
+    static inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+    char_type* assign(char_type* __s, size_t __n, char_type __a) _NOEXCEPT
+        {
+            return __libcpp_is_constant_evaluated()
+                       ? _VSTD::__assign_constexpr(__s, __n, __a)
+                       : __n == 0 ? __s : (char_type*)_VSTD::memset(__s, to_int_type(__a), __n);
+        }
+
+    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
+        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
+    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
+        {return char_type(__c);}
+    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
+        {return int_type((unsigned char)__c);}
+    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
+        {return __c1 == __c2;}
+    static inline _LIBCPP_CONSTEXPR int_type  eof() _NOEXCEPT
+        {return int_type(EOF);}
+};
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+int
+char_traits<char>::compare(const char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+{
+    if (__n == 0)
+        return 0;
+#if __has_feature(cxx_constexpr_string_builtins)
+    return __builtin_memcmp(__s1, __s2, __n);
+#elif _LIBCPP_STD_VER <= 14
+    return _VSTD::memcmp(__s1, __s2, __n);
+#else
+    for (; __n; --__n, ++__s1, ++__s2)
+    {
+        if (lt(*__s1, *__s2))
+            return -1;
+        if (lt(*__s2, *__s1))
+            return 1;
+    }
+    return 0;
+#endif
+}
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+const char*
+char_traits<char>::find(const char_type* __s, size_t __n, const char_type& __a) _NOEXCEPT
+{
+    if (__n == 0)
+        return nullptr;
+#if __has_feature(cxx_constexpr_string_builtins) && !defined(__CUDACC__)
+    return __builtin_char_memchr(__s, to_int_type(__a), __n);
+#elif _LIBCPP_STD_VER <= 14
+    return (const char_type*) _VSTD::memchr(__s, to_int_type(__a), __n);
+#else
+    for (; __n; --__n)
+    {
+        if (eq(*__s, __a))
+            return __s;
+        ++__s;
+    }
+    return nullptr;
+#endif
+}
+
+
+// char_traits<wchar_t>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+struct _LIBCPP_TEMPLATE_VIS char_traits<wchar_t>
+{
+    typedef wchar_t   char_type;
+    typedef wint_t    int_type;
+    typedef streamoff off_type;
+    typedef streampos pos_type;
+    typedef mbstate_t state_type;
+
+    static inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+    void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT {__c1 = __c2;}
+    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
+        {return __c1 == __c2;}
+    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
+        {return __c1 < __c2;}
+
+    static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    int compare(const char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT;
+    static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    size_t length(const char_type* __s) _NOEXCEPT;
+    static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const char_type* find(const char_type* __s, size_t __n, const char_type& __a) _NOEXCEPT;
+    static inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+    char_type* move(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+        {
+            return __libcpp_is_constant_evaluated()
+                       ? _VSTD::__move_constexpr(__s1, __s2, __n)
+                       : __n == 0 ? __s1 : _VSTD::wmemmove(__s1, __s2, __n);
+        }
+    static inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+    char_type* copy(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+        {
+            if (!__libcpp_is_constant_evaluated()) {
+                _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
+            }
+            return __libcpp_is_constant_evaluated()
+                       ? _VSTD::__copy_constexpr(__s1, __s2, __n)
+                       : __n == 0 ? __s1 : _VSTD::wmemcpy(__s1, __s2, __n);
+        }
+    static inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+    char_type* assign(char_type* __s, size_t __n, char_type __a) _NOEXCEPT
+        {
+            return __libcpp_is_constant_evaluated()
+                       ? _VSTD::__assign_constexpr(__s, __n, __a)
+                       : __n == 0 ? __s : _VSTD::wmemset(__s, __a, __n);
+        }
+    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
+        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
+    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
+        {return char_type(__c);}
+    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
+        {return int_type(__c);}
+    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
+        {return __c1 == __c2;}
+    static inline _LIBCPP_CONSTEXPR int_type eof() _NOEXCEPT
+        {return int_type(WEOF);}
+};
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+int
+char_traits<wchar_t>::compare(const char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+{
+    if (__n == 0)
+        return 0;
+#if __has_feature(cxx_constexpr_string_builtins) && !defined(__CUDACC__)
+    return __builtin_wmemcmp(__s1, __s2, __n);
+#elif _LIBCPP_STD_VER <= 14
+    return _VSTD::wmemcmp(__s1, __s2, __n);
+#else
+    for (; __n; --__n, ++__s1, ++__s2)
+    {
+        if (lt(*__s1, *__s2))
+            return -1;
+        if (lt(*__s2, *__s1))
+            return 1;
+    }
+    return 0;
+#endif
+}
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+size_t
+char_traits<wchar_t>::length(const char_type* __s) _NOEXCEPT
+{
+#if __has_feature(cxx_constexpr_string_builtins) && !defined(__CUDACC__)
+    return __builtin_wcslen(__s);
+#elif _LIBCPP_STD_VER <= 14
+    return _VSTD::wcslen(__s);
+#else
+    size_t __len = 0;
+    for (; !eq(*__s, char_type(0)); ++__s)
+        ++__len;
+    return __len;
+#endif
+}
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+const wchar_t*
+char_traits<wchar_t>::find(const char_type* __s, size_t __n, const char_type& __a) _NOEXCEPT
+{
+    if (__n == 0)
+        return nullptr;
+#if __has_feature(cxx_constexpr_string_builtins) && !defined(__CUDACC__)
+    return __builtin_wmemchr(__s, __a, __n);
+#elif _LIBCPP_STD_VER <= 14
+    return _VSTD::wmemchr(__s, __a, __n);
+#else
+    for (; __n; --__n)
+    {
+        if (eq(*__s, __a))
+            return __s;
+        ++__s;
+    }
+    return nullptr;
+#endif
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// Disable double inline warning.
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4141 )
+#endif
+template <class _Traits>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+inline size_t __char_traits_length_checked(const typename _Traits::char_type* __s) _NOEXCEPT {
+#if _LIBCPP_DEBUG_LEVEL >= 1
+  return __s ? _Traits::length(__s) : (_VSTD::__libcpp_debug_function(_VSTD::__libcpp_debug_info(__FILE__, __LINE__, "p == nullptr", "null pointer pass to non-null argument of char_traits<...>::length")), 0);
+#else
+  return _Traits::length(__s);
+#endif
+}
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS char_traits<char8_t>
+{
+    typedef char8_t        char_type;
+    typedef unsigned int   int_type;
+    typedef streamoff      off_type;
+    typedef u8streampos    pos_type;
+    typedef mbstate_t      state_type;
+
+    static inline constexpr void assign(char_type& __c1, const char_type& __c2) noexcept
+        {__c1 = __c2;}
+    static inline constexpr bool eq(char_type __c1, char_type __c2) noexcept
+        {return __c1 == __c2;}
+    static inline constexpr bool lt(char_type __c1, char_type __c2) noexcept
+        {return __c1 < __c2;}
+
+    static constexpr
+    int              compare(const char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT;
+
+    static constexpr
+    size_t           length(const char_type* __s) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY static constexpr
+    const char_type* find(const char_type* __s, size_t __n, const char_type& __a) _NOEXCEPT;
+
+    static _LIBCPP_CONSTEXPR_AFTER_CXX17
+    char_type*       move(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+        {
+            return __libcpp_is_constant_evaluated()
+                       ? _VSTD::__move_constexpr(__s1, __s2, __n)
+                       : __n == 0 ? __s1 : (char_type*)_VSTD::memmove(__s1, __s2, __n);
+        }
+
+    static _LIBCPP_CONSTEXPR_AFTER_CXX17
+    char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+        {
+            if (!__libcpp_is_constant_evaluated()) {
+                _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
+            }
+            return __libcpp_is_constant_evaluated()
+                       ? _VSTD::__copy_constexpr(__s1, __s2, __n)
+                       : __n == 0 ? __s1 : (char_type*)_VSTD::memcpy(__s1, __s2, __n);
+        }
+
+    static _LIBCPP_CONSTEXPR_AFTER_CXX17
+    char_type*       assign(char_type* __s, size_t __n, char_type __a) _NOEXCEPT
+        {
+            return __libcpp_is_constant_evaluated()
+                       ? _VSTD::__assign_constexpr(__s, __n, __a)
+                       : __n == 0 ? __s : (char_type*)_VSTD::memset(__s, to_int_type(__a), __n);
+        }
+
+    static inline constexpr int_type  not_eof(int_type __c) noexcept
+        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
+    static inline constexpr char_type to_char_type(int_type __c) noexcept
+        {return char_type(__c);}
+    static inline constexpr int_type to_int_type(char_type __c) noexcept
+        {return int_type(__c);}
+    static inline constexpr bool eq_int_type(int_type __c1, int_type __c2) noexcept
+        {return __c1 == __c2;}
+    static inline constexpr int_type eof() noexcept
+        {return int_type(EOF);}
+};
+
+// TODO use '__builtin_strlen' if it ever supports char8_t ??
+inline constexpr
+size_t
+char_traits<char8_t>::length(const char_type* __s) _NOEXCEPT
+{
+    size_t __len = 0;
+    for (; !eq(*__s, char_type(0)); ++__s)
+        ++__len;
+    return __len;
+}
+
+inline constexpr
+int
+char_traits<char8_t>::compare(const char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+{
+#if __has_feature(cxx_constexpr_string_builtins)
+    return __builtin_memcmp(__s1, __s2, __n);
+#else
+    for (; __n; --__n, ++__s1, ++__s2)
+    {
+        if (lt(*__s1, *__s2))
+            return -1;
+        if (lt(*__s2, *__s1))
+            return 1;
+    }
+    return 0;
+#endif
+}
+
+// TODO use '__builtin_char_memchr' if it ever supports char8_t ??
+inline constexpr
+const char8_t*
+char_traits<char8_t>::find(const char_type* __s, size_t __n, const char_type& __a) _NOEXCEPT
+{
+    for (; __n; --__n)
+    {
+        if (eq(*__s, __a))
+            return __s;
+        ++__s;
+    }
+    return nullptr;
+}
+
+#endif // #_LIBCPP_HAS_NO_CHAR8_T
+
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS char_traits<char16_t>
+{
+    typedef char16_t       char_type;
+    typedef uint_least16_t int_type;
+    typedef streamoff      off_type;
+    typedef u16streampos   pos_type;
+    typedef mbstate_t      state_type;
+
+    static inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+    void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT {__c1 = __c2;}
+    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
+        {return __c1 == __c2;}
+    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
+        {return __c1 < __c2;}
+
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    int              compare(const char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    size_t           length(const char_type* __s) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const char_type* find(const char_type* __s, size_t __n, const char_type& __a) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static char_type*       move(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static char_type*       assign(char_type* __s, size_t __n, char_type __a) _NOEXCEPT;
+
+    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
+        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
+    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
+        {return char_type(__c);}
+    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
+        {return int_type(__c);}
+    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
+        {return __c1 == __c2;}
+    static inline _LIBCPP_CONSTEXPR int_type eof() _NOEXCEPT
+        {return int_type(0xFFFF);}
+};
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+int
+char_traits<char16_t>::compare(const char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+{
+    for (; __n; --__n, ++__s1, ++__s2)
+    {
+        if (lt(*__s1, *__s2))
+            return -1;
+        if (lt(*__s2, *__s1))
+            return 1;
+    }
+    return 0;
+}
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+size_t
+char_traits<char16_t>::length(const char_type* __s) _NOEXCEPT
+{
+    size_t __len = 0;
+    for (; !eq(*__s, char_type(0)); ++__s)
+        ++__len;
+    return __len;
+}
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+const char16_t*
+char_traits<char16_t>::find(const char_type* __s, size_t __n, const char_type& __a) _NOEXCEPT
+{
+    for (; __n; --__n)
+    {
+        if (eq(*__s, __a))
+            return __s;
+        ++__s;
+    }
+    return nullptr;
+}
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+char16_t*
+char_traits<char16_t>::move(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+{
+    if (__n == 0) return __s1;
+    char_type* __r = __s1;
+    if (__s1 < __s2)
+    {
+        for (; __n; --__n, ++__s1, ++__s2)
+            assign(*__s1, *__s2);
+    }
+    else if (__s2 < __s1)
+    {
+        __s1 += __n;
+        __s2 += __n;
+        for (; __n; --__n)
+            assign(*--__s1, *--__s2);
+    }
+    return __r;
+}
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+char16_t*
+char_traits<char16_t>::copy(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+{
+    if (!__libcpp_is_constant_evaluated()) {
+        _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
+    }
+    char_type* __r = __s1;
+    for (; __n; --__n, ++__s1, ++__s2)
+        assign(*__s1, *__s2);
+    return __r;
+}
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+char16_t*
+char_traits<char16_t>::assign(char_type* __s, size_t __n, char_type __a) _NOEXCEPT
+{
+    char_type* __r = __s;
+    for (; __n; --__n, ++__s)
+        assign(*__s, __a);
+    return __r;
+}
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS char_traits<char32_t>
+{
+    typedef char32_t       char_type;
+    typedef uint_least32_t int_type;
+    typedef streamoff      off_type;
+    typedef u32streampos   pos_type;
+    typedef mbstate_t      state_type;
+
+    static inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+    void assign(char_type& __c1, const char_type& __c2) _NOEXCEPT {__c1 = __c2;}
+    static inline _LIBCPP_CONSTEXPR bool eq(char_type __c1, char_type __c2) _NOEXCEPT
+        {return __c1 == __c2;}
+    static inline _LIBCPP_CONSTEXPR bool lt(char_type __c1, char_type __c2) _NOEXCEPT
+        {return __c1 < __c2;}
+
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    int              compare(const char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    size_t           length(const char_type* __s) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const char_type* find(const char_type* __s, size_t __n, const char_type& __a) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static char_type*       move(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static char_type*       copy(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    static char_type*       assign(char_type* __s, size_t __n, char_type __a) _NOEXCEPT;
+
+    static inline _LIBCPP_CONSTEXPR int_type  not_eof(int_type __c) _NOEXCEPT
+        {return eq_int_type(__c, eof()) ? ~eof() : __c;}
+    static inline _LIBCPP_CONSTEXPR char_type to_char_type(int_type __c) _NOEXCEPT
+        {return char_type(__c);}
+    static inline _LIBCPP_CONSTEXPR int_type to_int_type(char_type __c) _NOEXCEPT
+        {return int_type(__c);}
+    static inline _LIBCPP_CONSTEXPR bool eq_int_type(int_type __c1, int_type __c2) _NOEXCEPT
+        {return __c1 == __c2;}
+    static inline _LIBCPP_CONSTEXPR int_type eof() _NOEXCEPT
+        {return int_type(0xFFFFFFFF);}
+};
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+int
+char_traits<char32_t>::compare(const char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+{
+    for (; __n; --__n, ++__s1, ++__s2)
+    {
+        if (lt(*__s1, *__s2))
+            return -1;
+        if (lt(*__s2, *__s1))
+            return 1;
+    }
+    return 0;
+}
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+size_t
+char_traits<char32_t>::length(const char_type* __s) _NOEXCEPT
+{
+    size_t __len = 0;
+    for (; !eq(*__s, char_type(0)); ++__s)
+        ++__len;
+    return __len;
+}
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX14
+const char32_t*
+char_traits<char32_t>::find(const char_type* __s, size_t __n, const char_type& __a) _NOEXCEPT
+{
+    for (; __n; --__n)
+    {
+        if (eq(*__s, __a))
+            return __s;
+        ++__s;
+    }
+    return nullptr;
+}
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+char32_t*
+char_traits<char32_t>::move(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+{
+    if (__n == 0) return __s1;
+    char_type* __r = __s1;
+    if (__s1 < __s2)
+    {
+        for (; __n; --__n, ++__s1, ++__s2)
+            assign(*__s1, *__s2);
+    }
+    else if (__s2 < __s1)
+    {
+        __s1 += __n;
+        __s2 += __n;
+        for (; __n; --__n)
+            assign(*--__s1, *--__s2);
+    }
+    return __r;
+}
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+char32_t*
+char_traits<char32_t>::copy(char_type* __s1, const char_type* __s2, size_t __n) _NOEXCEPT
+{
+    if (!__libcpp_is_constant_evaluated()) {
+        _LIBCPP_ASSERT(__s2 < __s1 || __s2 >= __s1+__n, "char_traits::copy overlapped range");
+    }
+    char_type* __r = __s1;
+    for (; __n; --__n, ++__s1, ++__s2)
+        assign(*__s1, *__s2);
+    return __r;
+}
+
+inline _LIBCPP_CONSTEXPR_AFTER_CXX17
+char32_t*
+char_traits<char32_t>::assign(char_type* __s, size_t __n, char_type __a) _NOEXCEPT
+{
+    char_type* __r = __s;
+    for (; __n; --__n, ++__s)
+        assign(*__s, __a);
+    return __r;
+}
+
+#endif // _LIBCPP_HAS_NO_UNICODE_CHARS
+
+// helper fns for basic_string and string_view
+
+// __str_find
+template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
+inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+__str_find(const _CharT *__p, _SizeT __sz,
+             _CharT __c, _SizeT __pos) _NOEXCEPT
+{
+    if (__pos >= __sz)
+        return __npos;
+    const _CharT* __r = _Traits::find(__p + __pos, __sz - __pos, __c);
+    if (__r == nullptr)
+        return __npos;
+    return static_cast<_SizeT>(__r - __p);
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_CONSTEXPR_AFTER_CXX11 const _CharT *
+__search_substring(const _CharT *__first1, const _CharT *__last1,
+                   const _CharT *__first2, const _CharT *__last2) _NOEXCEPT {
+  // Take advantage of knowing source and pattern lengths.
+  // Stop short when source is smaller than pattern.
+  const ptrdiff_t __len2 = __last2 - __first2;
+  if (__len2 == 0)
+    return __first1;
+
+  ptrdiff_t __len1 = __last1 - __first1;
+  if (__len1 < __len2)
+    return __last1;
+
+  // First element of __first2 is loop invariant.
+  _CharT __f2 = *__first2;
+  while (true) {
+    __len1 = __last1 - __first1;
+    // Check whether __first1 still has at least __len2 bytes.
+    if (__len1 < __len2)
+      return __last1;
+
+    // Find __f2 the first byte matching in __first1.
+    __first1 = _Traits::find(__first1, __len1 - __len2 + 1, __f2);
+    if (__first1 == nullptr)
+      return __last1;
+
+    // It is faster to compare from the first byte of __first1 even if we
+    // already know that it matches the first byte of __first2: this is because
+    // __first2 is most likely aligned, as it is user's "pattern" string, and
+    // __first1 + 1 is most likely not aligned, as the match is in the middle of
+    // the string.
+    if (_Traits::compare(__first1, __first2, __len2) == 0)
+      return __first1;
+
+    ++__first1;
+  }
+}
+
+template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
+inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+__str_find(const _CharT *__p, _SizeT __sz,
+       const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
+{
+    if (__pos > __sz)
+        return __npos;
+
+    if (__n == 0) // There is nothing to search, just return __pos.
+        return __pos;
+
+    const _CharT *__r = __search_substring<_CharT, _Traits>(
+        __p + __pos, __p + __sz, __s, __s + __n);
+
+    if (__r == __p + __sz)
+        return __npos;
+    return static_cast<_SizeT>(__r - __p);
+}
+
+
+// __str_rfind
+
+template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
+inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+__str_rfind(const _CharT *__p, _SizeT __sz,
+              _CharT __c, _SizeT __pos) _NOEXCEPT
+{
+    if (__sz < 1)
+        return __npos;
+    if (__pos < __sz)
+        ++__pos;
+    else
+        __pos = __sz;
+    for (const _CharT* __ps = __p + __pos; __ps != __p;)
+    {
+        if (_Traits::eq(*--__ps, __c))
+            return static_cast<_SizeT>(__ps - __p);
+    }
+    return __npos;
+}
+
+template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
+inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+__str_rfind(const _CharT *__p, _SizeT __sz,
+        const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
+{
+    __pos = _VSTD::min(__pos, __sz);
+    if (__n < __sz - __pos)
+        __pos += __n;
+    else
+        __pos = __sz;
+    const _CharT* __r = _VSTD::__find_end(
+                  __p, __p + __pos, __s, __s + __n, _Traits::eq,
+                        random_access_iterator_tag(), random_access_iterator_tag());
+    if (__n > 0 && __r == __p + __pos)
+        return __npos;
+    return static_cast<_SizeT>(__r - __p);
+}
+
+// __str_find_first_of
+template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
+inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+__str_find_first_of(const _CharT *__p, _SizeT __sz,
+                const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
+{
+    if (__pos >= __sz || __n == 0)
+        return __npos;
+    const _CharT* __r = _VSTD::__find_first_of_ce
+        (__p + __pos, __p + __sz, __s, __s + __n, _Traits::eq );
+    if (__r == __p + __sz)
+        return __npos;
+    return static_cast<_SizeT>(__r - __p);
+}
+
+
+// __str_find_last_of
+template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
+inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+__str_find_last_of(const _CharT *__p, _SizeT __sz,
+               const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
+    {
+    if (__n != 0)
+    {
+        if (__pos < __sz)
+            ++__pos;
+        else
+            __pos = __sz;
+        for (const _CharT* __ps = __p + __pos; __ps != __p;)
+        {
+            const _CharT* __r = _Traits::find(__s, __n, *--__ps);
+            if (__r)
+                return static_cast<_SizeT>(__ps - __p);
+        }
+    }
+    return __npos;
+}
+
+
+// __str_find_first_not_of
+template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
+inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+__str_find_first_not_of(const _CharT *__p, _SizeT __sz,
+                    const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
+{
+    if (__pos < __sz)
+    {
+        const _CharT* __pe = __p + __sz;
+        for (const _CharT* __ps = __p + __pos; __ps != __pe; ++__ps)
+            if (_Traits::find(__s, __n, *__ps) == nullptr)
+                return static_cast<_SizeT>(__ps - __p);
+    }
+    return __npos;
+}
+
+
+template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
+inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+__str_find_first_not_of(const _CharT *__p, _SizeT __sz,
+                          _CharT __c, _SizeT __pos) _NOEXCEPT
+{
+    if (__pos < __sz)
+    {
+        const _CharT* __pe = __p + __sz;
+        for (const _CharT* __ps = __p + __pos; __ps != __pe; ++__ps)
+            if (!_Traits::eq(*__ps, __c))
+                return static_cast<_SizeT>(__ps - __p);
+    }
+    return __npos;
+}
+
+
+// __str_find_last_not_of
+template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
+inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+__str_find_last_not_of(const _CharT *__p, _SizeT __sz,
+                   const _CharT* __s, _SizeT __pos, _SizeT __n) _NOEXCEPT
+{
+    if (__pos < __sz)
+        ++__pos;
+    else
+        __pos = __sz;
+    for (const _CharT* __ps = __p + __pos; __ps != __p;)
+        if (_Traits::find(__s, __n, *--__ps) == nullptr)
+            return static_cast<_SizeT>(__ps - __p);
+    return __npos;
+}
+
+
+template<class _CharT, class _SizeT, class _Traits, _SizeT __npos>
+inline _SizeT _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+__str_find_last_not_of(const _CharT *__p, _SizeT __sz,
+                         _CharT __c, _SizeT __pos) _NOEXCEPT
+{
+    if (__pos < __sz)
+        ++__pos;
+    else
+        __pos = __sz;
+    for (const _CharT* __ps = __p + __pos; __ps != __p;)
+        if (!_Traits::eq(*--__ps, __c))
+            return static_cast<_SizeT>(__ps - __p);
+    return __npos;
+}
+
+template<class _Ptr>
+inline _LIBCPP_INLINE_VISIBILITY
+size_t __do_string_hash(_Ptr __p, _Ptr __e)
+{
+    typedef typename iterator_traits<_Ptr>::value_type value_type;
+    return __murmur2_or_cityhash<size_t>()(__p, (__e-__p)*sizeof(value_type));
+}
+
+template <class _CharT, class _Iter, class _Traits=char_traits<_CharT> >
+struct __quoted_output_proxy
+{
+    _Iter  __first;
+    _Iter  __last;
+    _CharT  __delim;
+    _CharT  __escape;
+
+    __quoted_output_proxy(_Iter __f, _Iter __l, _CharT __d, _CharT __e)
+    : __first(__f), __last(__l), __delim(__d), __escape(__e) {}
+    //  This would be a nice place for a string_ref
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___STRING
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/android/locale_bionic.h b/contrib/libs/cxxsupp/libcxx/include/__support/android/locale_bionic.h
new file mode 100644
index 00000000000..733eb83642f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/android/locale_bionic.h
@@ -0,0 +1,71 @@
+// -*- C++ -*-
+//===-----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_ANDROID_LOCALE_BIONIC_H
+#define _LIBCPP_SUPPORT_ANDROID_LOCALE_BIONIC_H
+
+#if defined(__BIONIC__)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdlib.h>
+#include <xlocale.h>
+
+#ifdef __cplusplus
+}
+#endif
+
+#if defined(__ANDROID__)
+
+#include <android/api-level.h>
+#if defined(__has_include) && __has_include(<android/ndk-version.h>)
+#   include <android/ndk-version.h>
+#endif
+#if __ANDROID_API__ < 21
+#include <__support/xlocale/__posix_l_fallback.h>
+#endif
+// In NDK versions later than 16, locale-aware functions are provided by
+// legacy_stdlib_inlines.h
+#if __NDK_MAJOR__ <= 16
+#if __ANDROID_API__ < 21
+#include <__support/xlocale/__strtonum_fallback.h>
+#elif __ANDROID_API__ < 26
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+inline _LIBCPP_INLINE_VISIBILITY float strtof_l(const char* __nptr, char** __endptr,
+                                                locale_t) {
+  return ::strtof(__nptr, __endptr);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY double strtod_l(const char* __nptr,
+                                                 char** __endptr, locale_t) {
+  return ::strtod(__nptr, __endptr);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY long strtol_l(const char* __nptr, char** __endptr,
+                                               int __base, locale_t) {
+  return ::strtol(__nptr, __endptr, __base);
+}
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif // __ANDROID_API__ < 26
+
+#endif // __NDK_MAJOR__ <= 16
+#endif // defined(__ANDROID__)
+
+#endif // defined(__BIONIC__)
+#endif // _LIBCPP_SUPPORT_ANDROID_LOCALE_BIONIC_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/fuchsia/xlocale.h b/contrib/libs/cxxsupp/libcxx/include/__support/fuchsia/xlocale.h
new file mode 100644
index 00000000000..e8def81480e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/fuchsia/xlocale.h
@@ -0,0 +1,22 @@
+// -*- C++ -*-
+//===-----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_FUCHSIA_XLOCALE_H
+#define _LIBCPP_SUPPORT_FUCHSIA_XLOCALE_H
+
+#if defined(__Fuchsia__)
+
+#include <cstdlib>
+#include <cwchar>
+#include <__support/xlocale/__posix_l_fallback.h>
+#include <__support/xlocale/__strtonum_fallback.h>
+
+#endif // defined(__Fuchsia__)
+
+#endif // _LIBCPP_SUPPORT_FUCHSIA_XLOCALE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/ibm/gettod_zos.h b/contrib/libs/cxxsupp/libcxx/include/__support/ibm/gettod_zos.h
new file mode 100644
index 00000000000..46e02a6c8b8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/ibm/gettod_zos.h
@@ -0,0 +1,53 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_IBM_GETTOD_ZOS_H
+#define _LIBCPP_SUPPORT_IBM_GETTOD_ZOS_H
+
+#include <time.h>
+
+static inline int gettimeofdayMonotonic(struct timespec64* Output) {
+
+  // The POSIX gettimeofday() function is not available on z/OS. Therefore,
+  // we will call stcke and other hardware instructions in implement equivalent.
+  // Note that nanoseconds alone will overflow when reaching new epoch in 2042.
+
+  struct _t {
+    uint64_t Hi;
+    uint64_t Lo;
+  };
+  struct _t Value = {0, 0};
+  uint64_t CC = 0;
+  asm(" stcke %0\n"
+      " ipm %1\n"
+      " srlg %1,%1,28\n"
+      : "=m"(Value), "+r"(CC)::);
+
+  if (CC != 0) {
+    errno = EMVSTODNOTSET;
+    return CC;
+  }
+  uint64_t us = (Value.Hi >> 4);
+  uint64_t ns = ((Value.Hi & 0x0F) << 8) + (Value.Lo >> 56);
+  ns = (ns * 1000) >> 12;
+  us = us - 2208988800000000;
+
+  register uint64_t DivPair0 asm("r0"); // dividend (upper half), remainder
+  DivPair0 = 0;
+  register uint64_t DivPair1 asm("r1"); // dividend (lower half), quotient
+  DivPair1 = us;
+  uint64_t Divisor = 1000000;
+  asm(" dlgr %0,%2" : "+r"(DivPair0), "+r"(DivPair1) : "r"(Divisor) :);
+
+  Output->tv_sec = DivPair1;
+  Output->tv_nsec = DivPair0 * 1000 + ns;
+  return 0;
+}
+
+#endif // _LIBCPP_SUPPORT_IBM_GETTOD_ZOS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/ibm/limits.h b/contrib/libs/cxxsupp/libcxx/include/__support/ibm/limits.h
new file mode 100644
index 00000000000..45f1f1e3684
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/ibm/limits.h
@@ -0,0 +1,98 @@
+// -*- C++ -*-
+//===-----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_IBM_LIMITS_H
+#define _LIBCPP_SUPPORT_IBM_LIMITS_H
+
+#if !defined(_AIX) // Linux
+#include <math.h> // for HUGE_VAL, HUGE_VALF, HUGE_VALL, and NAN
+
+static const unsigned int _QNAN_F = 0x7fc00000;
+#define NANF (*((float *)(&_QNAN_F)))
+static const unsigned int _QNAN_LDBL128[4] = {0x7ff80000, 0x0, 0x0, 0x0};
+#define NANL (*((long double *)(&_QNAN_LDBL128)))
+static const unsigned int _SNAN_F= 0x7f855555;
+#define NANSF (*((float *)(&_SNAN_F)))
+static const unsigned int _SNAN_D[2] = {0x7ff55555, 0x55555555};
+#define NANS (*((double *)(&_SNAN_D)))
+static const unsigned int _SNAN_LDBL128[4] = {0x7ff55555, 0x55555555, 0x0, 0x0};
+#define NANSL (*((long double *)(&_SNAN_LDBL128)))
+
+#define __builtin_huge_val()     HUGE_VAL
+#define __builtin_huge_valf()    HUGE_VALF
+#define __builtin_huge_vall()    HUGE_VALL
+#define __builtin_nan(__dummy)   NAN
+#define __builtin_nanf(__dummy)  NANF
+#define __builtin_nanl(__dummy)  NANL
+#define __builtin_nans(__dummy)  NANS
+#define __builtin_nansf(__dummy) NANSF
+#define __builtin_nansl(__dummy) NANSL
+
+#else
+
+#include <math.h>
+#include <float.h> // limit constants
+
+#define __builtin_huge_val()     HUGE_VAL  //0x7ff0000000000000
+#define __builtin_huge_valf()    HUGE_VALF //0x7f800000
+#define __builtin_huge_vall()    HUGE_VALL //0x7ff0000000000000
+#define __builtin_nan(__dummy)   nan(__dummy) //0x7ff8000000000000
+#define __builtin_nanf(__dummy)  nanf(__dummy) // 0x7ff80000
+#define __builtin_nanl(__dummy)  nanl(__dummy) //0x7ff8000000000000
+#define __builtin_nans(__dummy)  DBL_SNAN //0x7ff5555555555555
+#define __builtin_nansf(__dummy) FLT_SNAN //0x7f855555
+#define __builtin_nansl(__dummy) DBL_SNAN //0x7ff5555555555555
+
+#define __FLT_MANT_DIG__   FLT_MANT_DIG
+#define __FLT_DIG__        FLT_DIG
+#define __FLT_RADIX__      FLT_RADIX
+#define __FLT_MIN_EXP__    FLT_MIN_EXP
+#define __FLT_MIN_10_EXP__ FLT_MIN_10_EXP
+#define __FLT_MAX_EXP__    FLT_MAX_EXP
+#define __FLT_MAX_10_EXP__ FLT_MAX_10_EXP
+#define __FLT_MIN__        FLT_MIN
+#define __FLT_MAX__        FLT_MAX
+#define __FLT_EPSILON__    FLT_EPSILON
+// predefined by XLC on LoP
+#define __FLT_DENORM_MIN__ 1.40129846e-45F
+
+#define __DBL_MANT_DIG__   DBL_MANT_DIG
+#define __DBL_DIG__        DBL_DIG
+#define __DBL_MIN_EXP__    DBL_MIN_EXP
+#define __DBL_MIN_10_EXP__ DBL_MIN_10_EXP
+#define __DBL_MAX_EXP__    DBL_MAX_EXP
+#define __DBL_MAX_10_EXP__ DBL_MAX_10_EXP
+#define __DBL_MIN__        DBL_MIN
+#define __DBL_MAX__        DBL_MAX
+#define __DBL_EPSILON__    DBL_EPSILON
+// predefined by XLC on LoP
+#define __DBL_DENORM_MIN__ 4.9406564584124654e-324
+
+#define __LDBL_MANT_DIG__   LDBL_MANT_DIG
+#define __LDBL_DIG__        LDBL_DIG
+#define __LDBL_MIN_EXP__    LDBL_MIN_EXP
+#define __LDBL_MIN_10_EXP__ LDBL_MIN_10_EXP
+#define __LDBL_MAX_EXP__    LDBL_MAX_EXP
+#define __LDBL_MAX_10_EXP__ LDBL_MAX_10_EXP
+#define __LDBL_MIN__        LDBL_MIN
+#define __LDBL_MAX__        LDBL_MAX
+#define __LDBL_EPSILON__    LDBL_EPSILON
+// predefined by XLC on LoP
+#if __LONGDOUBLE128
+#define __LDBL_DENORM_MIN__ 4.94065645841246544176568792868221e-324L
+#else
+#define __LDBL_DENORM_MIN__ 4.9406564584124654e-324L
+#endif
+
+// predefined by XLC on LoP
+#define __CHAR_BIT__    8
+
+#endif // _AIX
+
+#endif // _LIBCPP_SUPPORT_IBM_LIMITS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/ibm/locale_mgmt_zos.h b/contrib/libs/cxxsupp/libcxx/include/__support/ibm/locale_mgmt_zos.h
new file mode 100644
index 00000000000..90ad2c2c861
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/ibm/locale_mgmt_zos.h
@@ -0,0 +1,53 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_IBM_LOCALE_MGMT_ZOS_H
+#define _LIBCPP_SUPPORT_IBM_LOCALE_MGMT_ZOS_H
+
+#if defined(__MVS__)
+#include <locale.h>
+#include <string>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define _LC_MAX           LC_MESSAGES          /* highest real category */
+#define _NCAT             (_LC_MAX + 1)        /* maximum + 1 */
+
+#define _CATMASK(n)       (1 << (n))
+#define LC_COLLATE_MASK   _CATMASK(LC_COLLATE)
+#define LC_CTYPE_MASK     _CATMASK(LC_CTYPE)
+#define LC_MONETARY_MASK  _CATMASK(LC_MONETARY)
+#define LC_NUMERIC_MASK   _CATMASK(LC_NUMERIC)
+#define LC_TIME_MASK      _CATMASK(LC_TIME)
+#define LC_MESSAGES_MASK  _CATMASK(LC_MESSAGES)
+#define LC_ALL_MASK       (_CATMASK(_NCAT) - 1)
+
+typedef struct locale_struct {
+  int category_mask;
+  std::string lc_collate;
+  std::string lc_ctype;
+  std::string lc_monetary;
+  std::string lc_numeric;
+  std::string lc_time;
+  std::string lc_messages;
+} * locale_t;
+
+// z/OS does not have newlocale, freelocale and uselocale.
+// The functions below are workarounds in single thread mode.
+locale_t newlocale(int category_mask, const char* locale, locale_t base);
+void freelocale(locale_t locobj);
+locale_t uselocale(locale_t newloc);
+
+#ifdef __cplusplus
+}
+#endif
+#endif // defined(__MVS__)
+#endif // _LIBCPP_SUPPORT_IBM_LOCALE_MGMT_ZOS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/ibm/nanosleep.h b/contrib/libs/cxxsupp/libcxx/include/__support/ibm/nanosleep.h
new file mode 100644
index 00000000000..6ebcecc68a2
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/ibm/nanosleep.h
@@ -0,0 +1,56 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_IBM_NANOSLEEP_H
+#define _LIBCPP_SUPPORT_IBM_NANOSLEEP_H
+
+#include <unistd.h>
+
+inline int nanosleep(const struct timespec* __req, struct timespec* __rem) {
+   // The nanosleep() function is not available on z/OS. Therefore, we will call
+   // sleep() to sleep for whole seconds and usleep() to sleep for any remaining
+   // fraction of a second. Any remaining nanoseconds will round up to the next
+   // microsecond.
+  if (__req->tv_sec < 0 || __req->tv_nsec < 0 || __req->tv_nsec > 999999999) {
+    errno = EINVAL;
+    return -1;
+  }
+  useconds_t __micro_sec =
+      static_cast<useconds_t>((__req->tv_nsec + 999) / 1000);
+  time_t __sec = __req->tv_sec;
+  if (__micro_sec > 999999) {
+    ++__sec;
+     __micro_sec -= 1000000;
+   }
+  __sec = sleep(static_cast<unsigned int>(__sec));
+  if (__sec) {
+    if (__rem) {
+      // Updating the remaining time to sleep in case of unsuccessful call to sleep().
+      __rem->tv_sec = __sec;
+      __rem->tv_nsec = __micro_sec * 1000;
+    }
+    errno = EINTR;
+    return -1;
+  }
+   if (__micro_sec) {
+    int __rt = usleep(__micro_sec);
+    if (__rt != 0 && __rem) {
+      // The usleep() does not provide the amount of remaining time upon its failure,
+      // so the time slept will be ignored.
+      __rem->tv_sec = 0;
+      __rem->tv_nsec = __micro_sec * 1000;
+      // The errno is already set.
+      return -1;
+    }
+    return __rt;
+   }
+   return 0;
+}
+
+#endif // _LIBCPP_SUPPORT_IBM_NANOSLEEP_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/ibm/support.h b/contrib/libs/cxxsupp/libcxx/include/__support/ibm/support.h
new file mode 100644
index 00000000000..a7751b01766
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/ibm/support.h
@@ -0,0 +1,53 @@
+// -*- C++ -*-
+//===-----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_IBM_SUPPORT_H
+#define _LIBCPP_SUPPORT_IBM_SUPPORT_H
+
+extern "builtin" int __popcnt4(unsigned int);
+extern "builtin" int __popcnt8(unsigned long long);
+extern "builtin" unsigned int __cnttz4(unsigned int);
+extern "builtin" unsigned int __cnttz8(unsigned long long);
+extern "builtin" unsigned int __cntlz4(unsigned int);
+extern "builtin" unsigned int __cntlz8(unsigned long long);
+
+// Builtin functions for counting population
+#define __builtin_popcount(x) __popcnt4(x)
+#define __builtin_popcountll(x) __popcnt8(x)
+#if defined(__64BIT__)
+#define __builtin_popcountl(x) __builtin_popcountll(x)
+#else
+#define __builtin_popcountl(x) __builtin_popcount(x)
+#endif
+
+// Builtin functions for counting trailing zeros
+#define __builtin_ctz(x) __cnttz4(x)
+#define __builtin_ctzll(x) __cnttz8(x)
+#if defined(__64BIT__)
+#define __builtin_ctzl(x) __builtin_ctzll(x)
+#else
+#define __builtin_ctzl(x) __builtin_ctz(x)
+#endif
+
+// Builtin functions for counting leading zeros
+#define __builtin_clz(x) __cntlz4(x)
+#define __builtin_clzll(x) __cntlz8(x)
+#if defined(__64BIT__)
+#define __builtin_clzl(x) __builtin_clzll(x)
+#else
+#define __builtin_clzl(x) __builtin_clz(x)
+#endif
+
+#if defined(__64BIT__)
+#define __SIZE_WIDTH__ 64
+#else
+#define __SIZE_WIDTH__ 32
+#endif
+
+#endif // _LIBCPP_SUPPORT_IBM_SUPPORT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/ibm/xlocale.h b/contrib/libs/cxxsupp/libcxx/include/__support/ibm/xlocale.h
new file mode 100644
index 00000000000..15b8386dd36
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/ibm/xlocale.h
@@ -0,0 +1,133 @@
+// -*- C++ -*-
+//===-----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_IBM_XLOCALE_H
+#define _LIBCPP_SUPPORT_IBM_XLOCALE_H
+
+#include <__support/ibm/locale_mgmt_zos.h>
+#include <stdarg.h>
+
+#include "cstdlib"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if defined(__MVS__)
+#include <wctype.h>
+// POSIX routines
+#include <__support/xlocale/__posix_l_fallback.h>
+#endif // defined(__MVS__)
+
+namespace {
+
+struct __setAndRestore {
+  explicit __setAndRestore(locale_t locale) {
+    if (locale == (locale_t)0) {
+      __cloc = newlocale(LC_ALL_MASK, "C", /* base */ (locale_t)0);
+      __stored = uselocale(__cloc);
+    } else {
+      __stored = uselocale(locale);
+    }
+  }
+
+  ~__setAndRestore() {
+    uselocale(__stored);
+    if (__cloc)
+      freelocale(__cloc);
+  }
+
+private:
+  locale_t __stored = (locale_t)0;
+  locale_t __cloc = (locale_t)0;
+};
+
+} // namespace
+
+// The following are not POSIX routines.  These are quick-and-dirty hacks
+// to make things pretend to work
+static inline
+long long strtoll_l(const char *__nptr, char **__endptr,
+    int __base, locale_t locale) {
+  __setAndRestore __newloc(locale);
+  return strtoll(__nptr, __endptr, __base);
+}
+
+static inline
+long strtol_l(const char *__nptr, char **__endptr,
+    int __base, locale_t locale) {
+  __setAndRestore __newloc(locale);
+  return strtol(__nptr, __endptr, __base);
+}
+
+static inline
+double strtod_l(const char *__nptr, char **__endptr,
+    locale_t locale) {
+  __setAndRestore __newloc(locale);
+  return strtod(__nptr, __endptr);
+}
+
+static inline
+float strtof_l(const char *__nptr, char **__endptr,
+    locale_t locale) {
+  __setAndRestore __newloc(locale);
+  return strtof(__nptr, __endptr);
+}
+
+static inline
+long double strtold_l(const char *__nptr, char **__endptr,
+    locale_t locale) {
+  __setAndRestore __newloc(locale);
+  return strtold(__nptr, __endptr);
+}
+
+static inline
+unsigned long long strtoull_l(const char *__nptr, char **__endptr,
+    int __base, locale_t locale) {
+  __setAndRestore __newloc(locale);
+  return strtoull(__nptr, __endptr, __base);
+}
+
+static inline
+unsigned long strtoul_l(const char *__nptr, char **__endptr,
+    int __base, locale_t locale) {
+  __setAndRestore __newloc(locale);
+  return strtoul(__nptr, __endptr, __base);
+}
+
+static inline
+int vasprintf(char **strp, const char *fmt, va_list ap) {
+  const size_t buff_size = 256;
+  if ((*strp = (char *)malloc(buff_size)) == NULL) {
+    return -1;
+  }
+
+  va_list ap_copy;
+  // va_copy may not be provided by the C library in C++ 03 mode.
+#if defined(_LIBCPP_CXX03_LANG) && __has_builtin(__builtin_va_copy)
+  __builtin_va_copy(ap_copy, ap);
+#else
+  va_copy(ap_copy, ap);
+#endif
+  int str_size = vsnprintf(*strp, buff_size, fmt,  ap_copy);
+  va_end(ap_copy);
+
+  if ((size_t) str_size >= buff_size) {
+    if ((*strp = (char *)realloc(*strp, str_size + 1)) == NULL) {
+      return -1;
+    }
+    str_size = vsnprintf(*strp, str_size + 1, fmt,  ap);
+  }
+  return str_size;
+}
+
+#ifdef __cplusplus
+}
+#endif
+#endif // _LIBCPP_SUPPORT_IBM_XLOCALE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/musl/xlocale.h b/contrib/libs/cxxsupp/libcxx/include/__support/musl/xlocale.h
new file mode 100644
index 00000000000..e91701afd5c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/musl/xlocale.h
@@ -0,0 +1,47 @@
+// -*- C++ -*-
+//===-----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// This adds support for the extended locale functions that are currently
+// missing from the Musl C library.
+//
+// This only works when the specified locale is "C" or "POSIX", but that's
+// about as good as we can do without implementing full xlocale support
+// in Musl.
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_MUSL_XLOCALE_H
+#define _LIBCPP_SUPPORT_MUSL_XLOCALE_H
+
+#include <cstdlib>
+#include <cwchar>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+static inline long long wcstoll_l(const wchar_t *nptr, wchar_t **endptr,
+                                  int base, locale_t) {
+  return wcstoll(nptr, endptr, base);
+}
+
+static inline unsigned long long wcstoull_l(const wchar_t *nptr,
+                                            wchar_t **endptr, int base,
+                                            locale_t) {
+  return wcstoull(nptr, endptr, base);
+}
+
+static inline long double wcstold_l(const wchar_t *nptr, wchar_t **endptr,
+                                    locale_t) {
+  return wcstold(nptr, endptr);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _LIBCPP_SUPPORT_MUSL_XLOCALE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/newlib/xlocale.h b/contrib/libs/cxxsupp/libcxx/include/__support/newlib/xlocale.h
new file mode 100644
index 00000000000..b75f9263a4c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/newlib/xlocale.h
@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_NEWLIB_XLOCALE_H
+#define _LIBCPP_SUPPORT_NEWLIB_XLOCALE_H
+
+#if defined(_NEWLIB_VERSION)
+
+#include <cstdlib>
+#include <clocale>
+#include <cwctype>
+#include <ctype.h>
+#if !defined(__NEWLIB__) || __NEWLIB__ < 2 || \
+    __NEWLIB__ == 2 && __NEWLIB_MINOR__ < 5
+#include <__support/xlocale/__nop_locale_mgmt.h>
+#include <__support/xlocale/__posix_l_fallback.h>
+#include <__support/xlocale/__strtonum_fallback.h>
+#endif
+
+#endif // _NEWLIB_VERSION
+
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/openbsd/xlocale.h b/contrib/libs/cxxsupp/libcxx/include/__support/openbsd/xlocale.h
new file mode 100644
index 00000000000..49d66fde1e8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/openbsd/xlocale.h
@@ -0,0 +1,19 @@
+// -*- C++ -*-
+//===-----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_OPENBSD_XLOCALE_H
+#define _LIBCPP_SUPPORT_OPENBSD_XLOCALE_H
+
+#include <__support/xlocale/__strtonum_fallback.h>
+#include <clocale>
+#include <cstdlib>
+#include <ctype.h>
+#include <cwctype>
+
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/solaris/floatingpoint.h b/contrib/libs/cxxsupp/libcxx/include/__support/solaris/floatingpoint.h
new file mode 100644
index 00000000000..5f1628fbe4f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/solaris/floatingpoint.h
@@ -0,0 +1,13 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#define atof sun_atof
+#define strtod sun_strtod
+#include_next "floatingpoint.h"
+#undef atof
+#undef strtod
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/solaris/wchar.h b/contrib/libs/cxxsupp/libcxx/include/__support/solaris/wchar.h
new file mode 100644
index 00000000000..f01fd743a23
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/solaris/wchar.h
@@ -0,0 +1,46 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#define iswalpha sun_iswalpha
+#define iswupper sun_iswupper
+#define iswlower sun_iswlower
+#define iswdigit sun_iswdigit
+#define iswxdigit sun_iswxdigit
+#define iswalnum sun_iswalnum
+#define iswspace sun_iswspace
+#define iswpunct sun_iswpunct
+#define iswprint sun_iswprint
+#define iswgraph sun_iswgraph
+#define iswcntrl sun_iswcntrl
+#define iswctype sun_iswctype
+#define towlower sun_towlower
+#define towupper sun_towupper
+#define wcswcs sun_wcswcs
+#define wcswidth sun_wcswidth
+#define wcwidth sun_wcwidth
+#define wctype sun_wctype
+#define _WCHAR_T 1
+#include_next "wchar.h"
+#undef iswalpha
+#undef iswupper
+#undef iswlower
+#undef iswdigit
+#undef iswxdigit
+#undef iswalnum
+#undef iswspace
+#undef iswpunct
+#undef iswprint
+#undef iswgraph
+#undef iswcntrl
+#undef iswctype
+#undef towlower
+#undef towupper
+#undef wcswcs
+#undef wcswidth
+#undef wcwidth
+#undef wctype
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/solaris/xlocale.h b/contrib/libs/cxxsupp/libcxx/include/__support/solaris/xlocale.h
new file mode 100644
index 00000000000..05131f0272e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/solaris/xlocale.h
@@ -0,0 +1,76 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+////////////////////////////////////////////////////////////////////////////////
+// Minimal xlocale implementation for Solaris.  This implements the subset of
+// the xlocale APIs that libc++ depends on.
+////////////////////////////////////////////////////////////////////////////////
+#ifndef __XLOCALE_H_INCLUDED
+#define __XLOCALE_H_INCLUDED
+
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+int snprintf_l(char *__s, size_t __n, locale_t __l, const char *__format, ...);
+int asprintf_l(char **__s, locale_t __l, const char *__format, ...);
+
+int sscanf_l(const char *__s, locale_t __l, const char *__format, ...);
+
+int toupper_l(int __c, locale_t __l);
+int tolower_l(int __c, locale_t __l);
+
+struct lconv *localeconv(void);
+struct lconv *localeconv_l(locale_t __l);
+
+// FIXME: These are quick-and-dirty hacks to make things pretend to work
+static inline
+long long strtoll_l(const char *__nptr, char **__endptr,
+    int __base, locale_t __loc) {
+  return strtoll(__nptr, __endptr, __base);
+}
+static inline
+long strtol_l(const char *__nptr, char **__endptr,
+    int __base, locale_t __loc) {
+  return strtol(__nptr, __endptr, __base);
+}
+static inline
+unsigned long long strtoull_l(const char *__nptr, char **__endptr,
+    int __base, locale_t __loc) {
+  return strtoull(__nptr, __endptr, __base);
+}
+static inline
+unsigned long strtoul_l(const char *__nptr, char **__endptr,
+    int __base, locale_t __loc) {
+  return strtoul(__nptr, __endptr, __base);
+}
+static inline
+float strtof_l(const char *__nptr, char **__endptr,
+    locale_t __loc) {
+  return strtof(__nptr, __endptr);
+}
+static inline
+double strtod_l(const char *__nptr, char **__endptr,
+    locale_t __loc) {
+  return strtod(__nptr, __endptr);
+}
+static inline
+long double strtold_l(const char *__nptr, char **__endptr,
+    locale_t __loc) {
+  return strtold(__nptr, __endptr);
+}
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/win32/atomic_win32.h b/contrib/libs/cxxsupp/libcxx/include/__support/win32/atomic_win32.h
new file mode 100644
index 00000000000..e32bcf90735
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/win32/atomic_win32.h
@@ -0,0 +1,1164 @@
+#ifndef _LIBCPP_ATOMIC_WIN32
+#define _LIBCPP_ATOMIC_WIN32
+
+#include <__config>
+#include <type_traits>
+#include <intrin.h>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#define _Atomic(x) x
+
+#ifdef _M_ARM
+#define _MemoryBarrier __dmb(_ARM_BARRIER_ISH)
+#endif
+
+#ifdef _M_ARM64
+#define _MemoryBarrier __dmb(_ARM64_BARRIER_ISH)
+#endif
+
+#ifdef _M_X64
+#define _MemoryBarrier __faststorefence()
+#endif
+
+#ifdef _M_IX86
+#define _MemoryBarrier _mm_mfence()
+#endif
+
+namespace __atomic {
+template <typename _Tp> _Tp __create();
+
+template <typename _Tp, typename _Td>
+enable_if_t<sizeof(__create<_Tp>() = __create<_Td>()), char>
+    __test_atomic_assignable(int);
+template <typename _Tp, typename _Up>
+__two __test_atomic_assignable(...);
+
+template <typename _Tp, typename _Td>
+struct __can_assign {
+  static const bool value =
+      sizeof(__test_atomic_assignable<_Tp, _Td>(1)) == sizeof(char);
+};
+}  // namespace __atomic
+
+template <typename _Tp>
+static inline enable_if_t<is_assignable<volatile _Tp, _Tp>::value>
+__c11_atomic_init(volatile _Atomic(_Tp)* __a,  _Tp __val) {
+    *__a = __val;
+}
+
+template <typename _Tp>
+static inline enable_if_t<!is_assignable<volatile _Tp, _Tp>::value>
+__c11_atomic_init(volatile _Atomic(_Tp)* __a,  _Tp __val) {
+  volatile char* to = reinterpret_cast<volatile char*>(__a);
+  volatile char* end = to + sizeof(_Tp);
+  char* from = reinterpret_cast<char*>(&__val);
+  while (to != end) {
+    *to++ = *from++;
+  }
+}
+
+template <typename _Tp>
+static inline void __c11_atomic_init(_Atomic(_Tp)* __a,  _Tp __val) {
+    *__a = __val;
+}
+
+static inline void __c11_atomic_thread_fence(int __order) {
+    if (__order != static_cast<int>(memory_order_relaxed)) {
+#if defined(_M_IX86) || defined(_M_X64)
+        if (__order == static_cast<int>(memory_order_seq_cst)) {
+            _MemoryBarrier;
+        } else {
+            _ReadWriteBarrier();
+        }
+#else // ARM
+        _MemoryBarrier;
+#endif
+    }
+}
+
+static inline void __c11_atomic_signal_fence(int /*__order*/) {
+    _ReadWriteBarrier();
+}
+
+void __msvc_lock(void* p);
+void __msvc_unlock(void* p);
+
+template<class _Out, class _Tp>
+static inline _Out __msvc_cast(_Tp __val) {
+    _Out __result;
+    volatile char* to = reinterpret_cast<volatile char*>(&__result);
+    volatile char* end = to + sizeof(_Tp);
+    char* from = reinterpret_cast<char*>(&__val);
+    while (to != end) {
+      *to++ = *from++;
+    }
+    return __result;
+}
+
+
+
+static inline void __msvc_atomic_store8(volatile char* __a, char __val,
+                                        memory_order __order) {
+    if (__order == memory_order_relaxed) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        __iso_volatile_store8(__a, __val);
+#else
+        *__a = __val;
+#endif
+    } else if (__order == memory_order_release) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        _MemoryBarrier;
+        __iso_volatile_store8(__a, __val);
+#else
+        _ReadWriteBarrier();
+        *__a = __val;
+#endif
+    } else { // __order == memory_order_seq_cst)
+#if defined(_M_ARM) || defined(_M_ARM64)
+        _MemoryBarrier;
+        __iso_volatile_store8(__a, __val);
+        _MemoryBarrier;
+#else
+        _InterlockedExchange8(__a, __val);
+#endif
+    }
+}
+
+static inline void __msvc_atomic_store16(volatile short* __a, short __val,
+                                         memory_order __order) {
+    if (__order == memory_order_relaxed) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        __iso_volatile_store16(__a, __val);
+#else
+        *__a = __val;
+#endif
+    } else if (__order == memory_order_release) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        _MemoryBarrier;
+        __iso_volatile_store16(__a, __val);
+#else
+        _ReadWriteBarrier();
+        *__a = __val;
+#endif
+    } else { // __order == memory_order_seq_cst)
+#if defined(_M_ARM) || defined(_M_ARM64)
+        _MemoryBarrier;
+        __iso_volatile_store16(__a, __val);
+        _MemoryBarrier;
+#else
+        _InterlockedExchange16(__a, __val);
+#endif
+    }
+}
+
+static inline void __msvc_atomic_store32(volatile long* __a, long __val,
+                                         memory_order __order) {
+    if (__order == memory_order_relaxed) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        __iso_volatile_store32(__a, __val);
+#else
+        *__a = __val;
+#endif
+    } else if (__order == memory_order_release) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        _MemoryBarrier;
+        __iso_volatile_store32(__a, __val);
+#else
+        _ReadWriteBarrier();
+        *__a = __val;
+#endif
+    } else { // __order == memory_order_seq_cst)
+#if defined(_M_ARM) || defined(_M_ARM64)
+        _MemoryBarrier;
+        __iso_volatile_store32(__a, __val);
+        _MemoryBarrier;
+#else
+        _InterlockedExchange(__a, __val);
+#endif
+    }
+}
+
+static inline void __msvc_atomic_store64(volatile __int64* __a, __int64 __val,
+                                         memory_order __order) {
+#if defined(_M_IX86)
+    __int64 __tmp;
+    do {
+        __tmp = *__a;
+    } while (__tmp != _InterlockedCompareExchange64(__a, __val, __tmp));
+#else
+    if (__order == memory_order_relaxed) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        __iso_volatile_store64(__a, __val);
+#else
+        *__a = __val;
+#endif
+    } else if (__order == memory_order_release) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        _MemoryBarrier;
+        __iso_volatile_store64(__a, __val);
+#else
+        _ReadWriteBarrier();
+        *__a = __val;
+#endif
+    } else { // __order == memory_order_seq_cst)
+#if defined(_M_ARM) || defined(_M_ARM64)
+        _MemoryBarrier;
+        __iso_volatile_store64(__a, __val);
+        _MemoryBarrier;
+#else
+        _InterlockedExchange64(__a, __val);
+#endif
+    }
+#endif
+}
+
+template <typename _Tp>
+static inline void __c11_atomic_store(volatile _Atomic(_Tp)* __a,  _Tp __val,
+                                      int __order) {
+    if (sizeof(_Tp) == 1) {
+        __msvc_atomic_store8((volatile char*)__a, __msvc_cast<char>(__val), (memory_order)__order);
+    } else if (sizeof(_Tp) == 2 && alignof(_Tp) % 2 == 0) {
+        __msvc_atomic_store16((volatile short*)__a, __msvc_cast<short>(__val), (memory_order)__order);
+    } else if (sizeof(_Tp) == 4 && alignof(_Tp) % 4 == 0) {
+        __msvc_atomic_store32((volatile long*)__a, __msvc_cast<long>(__val), (memory_order)__order);
+    } else if (sizeof(_Tp) == 8 && alignof(_Tp) % 8 == 0) {
+        __msvc_atomic_store64((volatile __int64*)__a, __msvc_cast<__int64>(__val), (memory_order)__order);
+    } else {
+        __msvc_lock((void*)__a);
+        *(_Atomic(_Tp)*)__a = __val;
+        __msvc_unlock((void*)__a);
+    }
+}
+
+template<typename _Tp>
+static inline void __c11_atomic_store(_Atomic(_Tp)* __a, _Tp __val, int __order) {
+    __c11_atomic_store((volatile _Atomic(_Tp)*)__a, __val, __order);
+}
+
+static inline char __msvc_atomic_load8(volatile char* __a, memory_order __order) {
+    char __result;
+    if (__order == memory_order_relaxed) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        __result = __iso_volatile_load8(__a);
+#else
+        __result = *__a;
+#endif
+    } else if (__order == memory_order_acquire ||
+               __order == memory_order_consume) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        __result = __iso_volatile_load8(__a);
+        _MemoryBarrier;
+#else
+        __result = *__a;
+        _ReadWriteBarrier();
+#endif
+    } else { // __order == memory_order_seq_cst
+#if defined(_M_ARM) || defined(_M_ARM64)
+        _MemoryBarrier;
+        __result = __iso_volatile_load8(__a);
+        _MemoryBarrier;
+#else
+        _ReadWriteBarrier();
+        __result = *__a;
+        _ReadWriteBarrier();
+#endif
+    }
+    return __result;
+}
+
+static inline short __msvc_atomic_load16(volatile short* __a, memory_order __order) {
+    short __result;
+    if (__order == memory_order_relaxed) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        __result = __iso_volatile_load16(__a);
+#else
+        __result = *__a;
+#endif
+    } else if (__order == memory_order_acquire ||
+               __order == memory_order_consume) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        __result = __iso_volatile_load16(__a);
+        _MemoryBarrier;
+#else
+        __result = *__a;
+        _ReadWriteBarrier();
+#endif
+    } else { // __order == memory_order_seq_cst
+#if defined(_M_ARM) || defined(_M_ARM64)
+        _MemoryBarrier;
+        __result = __iso_volatile_load16(__a);
+        _MemoryBarrier;
+#else
+        _ReadWriteBarrier();
+        __result = *__a;
+        _ReadWriteBarrier();
+#endif
+    }
+    return __result;
+}
+
+static inline long __msvc_atomic_load32(volatile long* __a, memory_order __order) {
+    long __result;
+    if (__order == memory_order_relaxed) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        __result = __iso_volatile_load32(__a);
+#else
+        __result = *__a;
+#endif
+    } else if (__order == memory_order_acquire ||
+               __order == memory_order_consume) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        __result = __iso_volatile_load32(__a);
+        _MemoryBarrier;
+#else
+        __result = *__a;
+        _ReadWriteBarrier();
+#endif
+    } else { // __order == memory_order_seq_cst
+#if defined(_M_ARM) || defined(_M_ARM64)
+        _MemoryBarrier;
+        __result = __iso_volatile_load32(__a);
+        _MemoryBarrier;
+#else
+        _ReadWriteBarrier();
+        __result = *__a;
+        _ReadWriteBarrier();
+#endif
+    }
+    return __result;
+}
+
+static inline __int64 __msvc_atomic_load64(volatile __int64* __a, memory_order __order) {
+    __int64 __result;
+#if defined(_M_X86)
+    do {
+        __result = *__a;
+    } while (__result != _InterlockedCompareExchange64(__a, __result, __result));
+#else
+    if (__order == memory_order_relaxed) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        __result = __iso_volatile_load64(__a);
+#else
+        __result = *__a;
+#endif
+    } else if (__order == memory_order_acquire ||
+               __order == memory_order_consume) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        __result = __iso_volatile_load64(__a);
+        _MemoryBarrier;
+#else
+        __result = *__a;
+        _ReadWriteBarrier();
+#endif
+    } else { // __order == memory_order_seq_cst
+#if defined(_M_ARM) || defined(_M_ARM64)
+        _MemoryBarrier;
+        __result = __iso_volatile_load64(__a);
+        _MemoryBarrier;
+#else
+        _ReadWriteBarrier();
+        __result = *__a;
+        _ReadWriteBarrier();
+#endif
+    }
+#endif
+    return __result;
+}
+
+template<typename _Tp>
+static inline _Tp __c11_atomic_load(volatile _Atomic(_Tp)* __a, int __order) {
+    _Tp __result;
+    if (sizeof(_Tp) == 1) {
+        __result = __msvc_cast<_Tp>(__msvc_atomic_load8((volatile char*)__a, (memory_order)__order));
+    } else if (sizeof(_Tp) == 2 && alignof(_Tp) % 2 == 0) {
+        __result = __msvc_cast<_Tp>(__msvc_atomic_load16((volatile short*)__a, (memory_order)__order));
+    } else if (sizeof(_Tp) == 4 && alignof(_Tp) % 4 == 0) {
+        __result = __msvc_cast<_Tp>(__msvc_atomic_load32((volatile long*)__a, (memory_order)__order));
+    } else if (sizeof(_Tp) == 8 && alignof(_Tp) % 8 == 0) {
+        __result = __msvc_cast<_Tp>(__msvc_atomic_load64((volatile __int64*)__a, (memory_order)__order));
+    } else {
+        __msvc_lock((void*)__a);
+        __result = *(_Atomic(_Tp)*)__a;
+        __msvc_unlock((void*)__a);
+    }
+    return __result;
+}
+
+template<typename _Tp>
+static inline _Tp __c11_atomic_load(_Atomic(_Tp)* __a, int __order) {
+    return __c11_atomic_load((volatile _Atomic(_Tp)*)__a, __order);
+}
+
+static inline char __msvc_atomic_exchange8(volatile char* __a, char __val,
+                                           memory_order __order) {
+    char __result;
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        __result = _InterlockedExchange8_nf(__a, __val);
+    } else if (__order == memory_order_acquire ||
+               __order == memory_order_consume) {
+        __result = _InterlockedExchange8_acq(__a, __val);
+    } else if (__order == memory_order_release) {
+        __result = _InterlockedExchange8_rel(__a, __val);
+    } else {
+        __result = _InterlockedExchange8(__a, __val);
+    }
+#else
+  (void)__order;
+  __result = _InterlockedExchange8(__a, __val);
+#endif
+  return __result;
+}
+
+static inline short __msvc_atomic_exchange16(volatile short* __a, short __val,
+                                             memory_order __order) {
+    short __result;
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        __result = _InterlockedExchange16_nf(__a, __val);
+    } else if (__order == memory_order_acquire ||
+               __order == memory_order_consume) {
+        __result = _InterlockedExchange16_acq(__a, __val);
+    } else if (__order == memory_order_release) {
+        __result = _InterlockedExchange16_rel(__a, __val);
+    } else {
+        __result = _InterlockedExchange16(__a, __val);
+    }
+#else
+  (void)__order;
+  __result = _InterlockedExchange16(__a, __val);
+#endif
+  return __result;
+}
+
+static inline long __msvc_atomic_exchange32(volatile long* __a, long __val,
+                                            memory_order __order) {
+    long __result;
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        __result = _InterlockedExchange_nf(__a, __val);
+    } else if (__order == memory_order_acquire ||
+               __order == memory_order_consume) {
+        __result = _InterlockedExchange_acq(__a, __val);
+    } else if (__order == memory_order_release) {
+        __result = _InterlockedExchange_rel(__a, __val);
+    } else {
+        __result = _InterlockedExchange(__a, __val);
+    }
+#else
+  (void)__order;
+  __result = _InterlockedExchange(__a, __val);
+#endif
+  return __result;
+}
+
+static inline __int64 __msvc_atomic_exchange64(volatile __int64* __a, __int64 __val,
+                                            memory_order __order) {
+    __int64 __result;
+#if defined(_M_IX86)
+    do {
+        __result = *__a;
+    } while (__result != _InterlockedCompareExchange64(__a, __val, __result));
+#elif defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        __result = _InterlockedExchange64_nf(__a, __val);
+    } else if (__order == memory_order_acquire ||
+               __order == memory_order_consume) {
+        __result = _InterlockedExchange64_acq(__a, __val);
+    } else if (__order == memory_order_release) {
+        __result = _InterlockedExchange64_rel(__a, __val);
+    } else {
+        __result = _InterlockedExchange64(__a, __val);
+    }
+#else
+  (void)__order;
+  __result = _InterlockedExchange64(__a, __val);
+#endif
+  return __result;
+}
+
+template<typename _Tp>
+static inline _Tp __c11_atomic_exchange(volatile _Atomic(_Tp)* __a, _Tp __val,
+                                        int __order) {
+    _Tp __result;
+    if (sizeof(_Tp) == 1) {
+        __result = __msvc_cast<_Tp>(
+            __msvc_atomic_exchange8((volatile char*)__a, __msvc_cast<char>(__val), (memory_order)__order));
+    } else if (sizeof(_Tp) == 2 && alignof(_Tp) % 2 == 0) {
+        __result = __msvc_cast<_Tp>(
+            __msvc_atomic_exchange16((volatile short*)__a, __msvc_cast<short>(__val), (memory_order)__order));
+    } else if (sizeof(_Tp) == 4 && alignof(_Tp) % 4 == 0) {
+        __result = __msvc_cast<_Tp>(
+            __msvc_atomic_exchange32((volatile long*)__a, __msvc_cast<long>(__val), (memory_order)__order));
+    } else if (sizeof(_Tp) == 8 && alignof(_Tp) % 8 == 0) {
+        __result = __msvc_cast<_Tp>(
+            __msvc_atomic_exchange64((volatile __int64*)__a, __msvc_cast<__int64>(__val), (memory_order)__order));
+    } else {
+        __msvc_lock((void*)__a);
+        __result = *(_Atomic(_Tp)*)__a;
+        *(_Atomic(_Tp)*)__a = __val;
+        __msvc_unlock((void*)__a);
+    }
+    return __result;
+}
+
+template<typename _Tp>
+static inline _Tp __c11_atomic_exchange(_Atomic(_Tp)* __a, _Tp __val,
+                                        int __order) {
+    return __c11_atomic_exchange((volatile _Atomic(_Tp)*)__a, __val, __order);
+}
+
+static inline bool __msvc_atomic_compare_exchange8(volatile char* __a, char __value, char* __expected,
+                                                   memory_order __order) {
+    char __compare = *__expected;
+    char __before;
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        __before = _InterlockedCompareExchange8_nf(__a, __value, __compare);
+    } else if (__order == memory_order_acquire) {
+        __before = _InterlockedCompareExchange8_acq(__a, __value, __compare);
+    } else if (__order == memory_order_release) {
+        __before = _InterlockedCompareExchange8_rel(__a, __value, __compare);
+    } else {
+        __before = _InterlockedCompareExchange8(__a, __value, __compare);
+    }
+#else
+    (void)__order;
+    __before = _InterlockedCompareExchange8(__a, __value, __compare);
+#endif
+    if (__before == __compare) {
+        return true;
+    }
+    *__expected = __before;
+    return false;
+}
+
+static inline bool __msvc_atomic_compare_exchange16(volatile short* __a, short __value, short* __expected,
+                                                    memory_order __order) {
+    short __compare = *__expected;
+    short __before;
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        __before = _InterlockedCompareExchange16_nf(__a, __value, __compare);
+    } else if (__order == memory_order_acquire) {
+        __before = _InterlockedCompareExchange16_acq(__a, __value, __compare);
+    } else if (__order == memory_order_release) {
+        __before = _InterlockedCompareExchange16_rel(__a, __value, __compare);
+    } else {
+        __before = _InterlockedCompareExchange16(__a, __value, __compare);
+    }
+#else
+    (void)__order;
+    __before = _InterlockedCompareExchange16(__a, __value, __compare);
+#endif
+    if (__before == __compare) {
+        return true;
+    }
+    *__expected = __before;
+    return false;
+}
+
+static inline bool __msvc_atomic_compare_exchange32(volatile long* __a, long __value, long* __expected,
+                                                    memory_order __order) {
+    long __compare = *__expected;
+    long __before;
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        __before = _InterlockedCompareExchange_nf(__a, __value, __compare);
+    } else if (__order == memory_order_acquire) {
+        __before = _InterlockedCompareExchange_acq(__a, __value, __compare);
+    } else if (__order == memory_order_release) {
+        __before = _InterlockedCompareExchange_rel(__a, __value, __compare);
+    } else {
+        __before = _InterlockedCompareExchange(__a, __value, __compare);
+    }
+#else
+    (void)__order;
+    __before = _InterlockedCompareExchange(__a, __value, __compare);
+#endif
+    if (__before == __compare) {
+        return true;
+    }
+    *__expected = __before;
+    return false;
+}
+
+static inline bool __msvc_atomic_compare_exchange64(volatile __int64* __a, __int64 __value, __int64* __expected,
+                                                    memory_order __order) {
+    __int64 __compare = *__expected;
+    __int64 __before;
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        __before = _InterlockedCompareExchange64_nf(__a, __value, __compare);
+    } else if (__order == memory_order_acquire) {
+        __before = _InterlockedCompareExchange64_acq(__a, __value, __compare);
+    } else if (__order == memory_order_release) {
+        __before = _InterlockedCompareExchange64_rel(__a, __value, __compare);
+    } else {
+        __before = _InterlockedCompareExchange64(__a, __value, __compare);
+    }
+#else
+    (void)__order;
+    __before = _InterlockedCompareExchange64(__a, __value, __compare);
+#endif
+    if (__before == __compare) {
+        return true;
+    }
+    *__expected = __before;
+    return false;
+}
+
+
+static inline memory_order constexpr __msvc_top_memory_order(memory_order __order1, memory_order __order2) {
+    return
+        (__order1 == memory_order_relaxed && __order2 == memory_order_relaxed) ? memory_order_relaxed :
+        ((__order1 == memory_order_relaxed || __order1 == memory_order_acquire || __order1 == memory_order_consume) &&
+         (__order2 == memory_order_relaxed || __order2 == memory_order_relaxed || __order2 == memory_order_consume)) ? memory_order_acquire :
+        ((__order1 == memory_order_relaxed || __order1 == memory_order_release) &&
+         (__order2 == memory_order_relaxed || __order2 == memory_order_release)) ? memory_order_release :
+        (__order1 != memory_order_seq_cst && __order2 != memory_order_seq_cst) ? memory_order_acq_rel :
+        memory_order_seq_cst;
+}
+
+template<typename _Tp>
+static inline bool __c11_atomic_compare_exchange_strong(
+    volatile _Atomic(_Tp)* __a, _Tp* __expected, _Tp __value,
+    int __order_success, int __order_failure) {
+    memory_order __order = __msvc_top_memory_order((memory_order)__order_success, (memory_order)__order_failure);
+    if (sizeof(_Tp) == 1) {
+        return __msvc_atomic_compare_exchange8((volatile char*)__a, __msvc_cast<char>(__value), (char*)__expected, __order);
+    } else if (sizeof(_Tp) == 2 && alignof(_Tp) % 2 == 0) {
+        return __msvc_atomic_compare_exchange16((volatile short*)__a, __msvc_cast<short>(__value), (short*)__expected, __order);
+    } else if (sizeof(_Tp) == 4 && alignof(_Tp) % 4 == 0) {
+        return __msvc_atomic_compare_exchange32((volatile long*)__a, __msvc_cast<long>(__value), (long*)__expected, __order);
+    } else if (sizeof(_Tp) == 8 && alignof(_Tp) % 8 == 0) {
+        return __msvc_atomic_compare_exchange64((volatile __int64*)__a, __msvc_cast<__int64>(__value), (__int64*)__expected, __order);
+    } else {
+        bool __result;
+        __msvc_lock((void*)__a);
+        volatile char* __p_a = reinterpret_cast<volatile char*>(__a);
+        volatile char* __p_a_end = __p_a + sizeof(_Atomic(_Tp));
+        volatile char* __p_expected = reinterpret_cast<volatile char*>(__expected);
+        bool __equal = true;
+        while (__p_a != __p_a_end) {
+            if (*__p_a++ != *__p_expected++) {
+                __equal = false;
+                break;
+            }
+        }
+        if (__equal) {
+            *(_Atomic(_Tp)*)__a = __value;
+            __result = true;
+        } else {
+            *__expected = *(_Atomic(_Tp)*)__a;
+            __result = false;
+        }
+        __msvc_unlock((void*)__a);
+        return __result;
+    }
+}
+
+template<typename _Tp>
+static inline bool __c11_atomic_compare_exchange_strong(
+    _Atomic(_Tp)* __a, _Tp* __expected, _Tp __value,
+    int __order_success, int __order_failure) {
+    return __c11_atomic_compare_exchange_strong(
+        (volatile _Atomic(_Tp)*)__a, __expected, __value, __order_success, __order_failure);
+}
+
+template<typename _Tp>
+static inline bool __c11_atomic_compare_exchange_weak(
+    volatile _Atomic(_Tp)* __a, _Tp* __expected, _Tp __value,
+    int __order_success, int __order_failure) {
+    return __c11_atomic_compare_exchange_strong(__a, __expected, __value, __order_success, __order_failure);
+}
+
+template<typename _Tp>
+static inline bool __c11_atomic_compare_exchange_weak(
+    _Atomic(_Tp)* __a, _Tp* __expected, _Tp __value,
+    int __order_success, int __order_failure) {
+    return __c11_atomic_compare_exchange_strong(__a, __expected, __value, __order_success, __order_failure);
+}
+
+template <typename _Tp>
+struct __msvc_skip { enum {value = 1}; };
+
+template <typename _Tp>
+struct __msvc_skip<_Tp*> { enum {value = sizeof(_Tp)}; };
+
+// FIXME: Haven't figured out what the spec says about using arrays with
+// atomic_fetch_add. Force a failure rather than creating bad behavior.
+template <typename _Tp>
+struct __msvc_skip<_Tp[]> { };
+template <typename _Tp, int n>
+struct __msvc_skip<_Tp[n]> { };
+
+static inline char __msvc_atomic_fetch_add8(volatile char* __a, char __delta,
+                                            memory_order __order) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedExchangeAdd8_nf(__a, __delta);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedExchangeAdd8_acq(__a, __delta);
+    } else if (__order == memory_order_release) {
+        return _InterlockedExchangeAdd8_rel(__a, __delta);
+    } else {
+        return _InterlockedExchangeAdd8(__a, __delta);
+    }
+#else
+    (void)__order;
+    return _InterlockedExchangeAdd8(__a, __delta);
+#endif
+}
+
+static inline short __msvc_atomic_fetch_add16(volatile short* __a, short __delta,
+                                              memory_order __order) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedExchangeAdd16_nf(__a, __delta);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedExchangeAdd16_acq(__a, __delta);
+    } else if (__order == memory_order_release) {
+        return _InterlockedExchangeAdd16_rel(__a, __delta);
+    } else {
+        return _InterlockedExchangeAdd16(__a, __delta);
+    }
+#else
+    (void)__order;
+    return _InterlockedExchangeAdd16(__a, __delta);
+#endif
+}
+
+static inline long __msvc_atomic_fetch_add32(volatile long* __a, long __delta,
+                                             memory_order __order) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedExchangeAdd_nf(__a, __delta);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedExchangeAdd_acq(__a, __delta);
+    } else if (__order == memory_order_release) {
+        return _InterlockedExchangeAdd_rel(__a, __delta);
+    } else {
+        return _InterlockedExchangeAdd(__a, __delta);
+    }
+#else
+    (void)__order;
+    return _InterlockedExchangeAdd(__a, __delta);
+#endif
+}
+
+static inline __int64 __msvc_atomic_fetch_add64(volatile __int64* __a, __int64 __delta,
+                                                memory_order __order) {
+#if defined(_M_IX86)
+    __int64 __tmp;
+    do {
+        __tmp = *__a;
+    } while (__tmp != _InterlockedCompareExchange64(__a, __tmp + __delta, __tmp));
+    return __tmp;
+#elif defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedExchangeAdd64_nf(__a, __delta);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedExchangeAdd64_acq(__a, __delta);
+    } else if (__order == memory_order_release) {
+        return _InterlockedExchangeAdd64_rel(__a, __delta);
+    } else {
+        return _InterlockedExchangeAdd64(__a, __delta);
+    }
+#else
+    (void)__order;
+    return _InterlockedExchangeAdd64(__a, __delta);
+#endif
+}
+
+template <typename _Tp, typename _Td>
+static inline _Tp __c11_atomic_fetch_add(volatile _Atomic(_Tp)* __a,
+                                         _Td __delta, int __order) {
+    _Td __real_delta = __delta * __msvc_skip<_Tp>::value;
+    if (sizeof(_Tp) == 1 && std::is_integral<_Tp>::value) {
+        return __msvc_cast<_Tp>(__msvc_atomic_fetch_add8((volatile char*)__a, (char)__real_delta, (memory_order)__order));
+    } else if (sizeof(_Tp) == 2 && std::is_integral<_Tp>::value) {
+        return __msvc_cast<_Tp>(__msvc_atomic_fetch_add16((volatile short*)__a, (short)__real_delta, (memory_order)__order));
+    } else if (sizeof(_Tp) == 4 && (std::is_integral<_Tp>::value || std::is_pointer<_Tp>::value)) {
+        return __msvc_cast<_Tp>(__msvc_atomic_fetch_add32((volatile long*)__a, (long)__real_delta, (memory_order)__order));
+    } else if (sizeof(_Tp) == 8 && (std::is_integral<_Tp>::value || std::is_pointer<_Tp>::value)) {
+        return __msvc_cast<_Tp>(__msvc_atomic_fetch_add64((volatile __int64*)__a, (__int64)__real_delta, (memory_order)__order));
+    } else {
+        __msvc_lock((void*)__a);
+        _Tp __result = *(_Atomic(_Tp)*)__a;
+        *(_Atomic(_Tp)*)__a += __delta;
+        __msvc_unlock((void*)__a);
+        return __result;
+    }
+}
+
+template <typename _Tp, typename _Td>
+static inline _Tp __c11_atomic_fetch_add(_Atomic(_Tp)* __a,
+                                         _Td __delta, int __order) {
+    return __c11_atomic_fetch_add((volatile _Atomic(_Tp)*) __a, __delta, __order);
+}
+
+template <typename _Tp, typename _Td>
+static inline _Tp __c11_atomic_fetch_sub(volatile _Atomic(_Tp)* __a,
+                                         _Td __delta, int __order) {
+    _Td __real_delta = __delta * __msvc_skip<_Tp>::value;
+    // Cast __real_delta to unsigned types to avoid integer overflow on negation.
+    if (sizeof(_Tp) == 1 && std::is_integral<_Tp>::value) {
+        return __msvc_cast<_Tp>(__msvc_atomic_fetch_add8((volatile char*)__a, -(unsigned char)__real_delta, (memory_order)__order));
+    } else if (sizeof(_Tp) == 2 && std::is_integral<_Tp>::value) {
+        return __msvc_cast<_Tp>(__msvc_atomic_fetch_add16((volatile short*)__a, -(unsigned short)__real_delta, (memory_order)__order));
+    } else if (sizeof(_Tp) == 4 && (std::is_integral<_Tp>::value || std::is_pointer<_Tp>::value)) {
+        return __msvc_cast<_Tp>(__msvc_atomic_fetch_add32((volatile long*)__a, -(unsigned long)__real_delta, (memory_order)__order));
+    } else if (sizeof(_Tp) == 8 && (std::is_integral<_Tp>::value || std::is_pointer<_Tp>::value)) {
+        return __msvc_cast<_Tp>(__msvc_atomic_fetch_add64((volatile __int64*)__a, -(unsigned __int64)__real_delta, (memory_order)__order));
+    } else {
+        __msvc_lock((void*)__a);
+        _Tp __result = *(_Atomic(_Tp)*)__a;
+        *(_Atomic(_Tp)*)__a -= __delta;
+        __msvc_unlock((void*)__a);
+        return __result;
+    }
+}
+
+template <typename _Tp, typename _Td>
+static inline _Tp __c11_atomic_fetch_sub(_Atomic(_Tp)* __a,
+                                         _Td __delta, int __order) {
+    return __c11_atomic_fetch_sub((volatile _Atomic(_Tp)*) __a, __delta, __order);
+}
+
+static inline char __msvc_atomic_fetch_and8(volatile char* __a, char __value,
+                                            memory_order __order) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedAnd8_nf(__a, __value);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedAnd8_acq(__a, __value);
+    } else if (__order == memory_order_release) {
+        return _InterlockedAnd8_rel(__a, __value);
+    } else {
+        return _InterlockedAnd8(__a, __value);
+    }
+#else
+    (void)__order;
+    return _InterlockedAnd8(__a, __value);
+#endif
+}
+
+static inline short __msvc_atomic_fetch_and16(volatile short* __a, short __value,
+                                              memory_order __order) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedAnd16_nf(__a, __value);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedAnd16_acq(__a, __value);
+    } else if (__order == memory_order_release) {
+        return _InterlockedAnd16_rel(__a, __value);
+    } else {
+        return _InterlockedAnd16(__a, __value);
+    }
+#else
+    (void)__order;
+    return _InterlockedAnd16(__a, __value);
+#endif
+}
+
+static inline long __msvc_atomic_fetch_and32(volatile long* __a, long __value,
+                                             memory_order __order) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedAnd_nf(__a, __value);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedAnd_acq(__a, __value);
+    } else if (__order == memory_order_release) {
+        return _InterlockedAnd_rel(__a, __value);
+    } else {
+        return _InterlockedAnd(__a, __value);
+    }
+#else
+    (void)__order;
+    return _InterlockedAnd(__a, __value);
+#endif
+}
+
+static inline __int64 __msvc_atomic_fetch_and64(volatile __int64* __a, __int64 __value,
+                                                memory_order __order) {
+#if defined(_M_IX86)
+    __int64 __tmp;
+    do {
+        __tmp = *__a;
+    } while (__tmp != _InterlockedCompareExchange64(__a, __tmp & __value, __tmp));
+    return __tmp;
+#elif defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedAnd64_nf(__a, __value);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedAnd64_acq(__a, __value);
+    } else if (__order == memory_order_release) {
+        return _InterlockedAnd64_rel(__a, __value);
+    } else {
+        return _InterlockedAnd64(__a, __value);
+    }
+#else
+    (void)__order;
+    return _InterlockedAnd64(__a, __value);
+#endif
+}
+
+template <typename _Tp>
+static inline _Tp __c11_atomic_fetch_and(volatile _Atomic(_Tp)* __a,
+                                         _Tp __value, int __order) {
+    if (sizeof(_Tp) == 1 && (std::is_integral<_Tp>::value || std::is_same<std::remove_cv_t<_Tp>, bool>::value)) {
+        return __msvc_cast<_Tp>(__msvc_atomic_fetch_and8((volatile char*)__a, __msvc_cast<char>(__value), (memory_order)__order));
+    } else if (sizeof(_Tp) == 2 && std::is_integral<_Tp>::value) {
+        return (_Tp)__msvc_atomic_fetch_and16((volatile short*)__a, (short)__value, (memory_order)__order);
+    } else if (sizeof(_Tp) == 4 && std::is_integral<_Tp>::value) {
+        return (_Tp) __msvc_atomic_fetch_and32((volatile long*)__a, (long)__value, (memory_order)__order);
+    } else if (sizeof(_Tp) == 8 && std::is_integral<_Tp>::value) {
+        return (_Tp) __msvc_atomic_fetch_and64((volatile __int64*)__a, (__int64)__value, (memory_order)__order);
+    } else {
+        __msvc_lock((void*)__a);
+        _Tp __result = *(_Atomic(_Tp)*)__a;
+        *(_Atomic(_Tp)*)__a &= __value;
+        __msvc_unlock((void*)__a);
+        return __result;
+    }
+}
+
+template <typename _Tp>
+static inline _Tp __c11_atomic_fetch_and(_Atomic(_Tp)* __a,
+                                         _Tp __value, int __order) {
+    return __c11_atomic_fetch_and((volatile _Atomic(_Tp)*)__a, __value, __order);
+}
+
+static inline char __msvc_atomic_fetch_or8(volatile char* __a, char __value,
+                                           memory_order __order) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedOr8_nf(__a, __value);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedOr8_acq(__a, __value);
+    } else if (__order == memory_order_release) {
+        return _InterlockedOr8_rel(__a, __value);
+    } else {
+        return _InterlockedOr8(__a, __value);
+    }
+#else
+    (void)__order;
+    return _InterlockedOr8(__a, __value);
+#endif
+}
+
+static inline short __msvc_atomic_fetch_or16(volatile short* __a, short __value,
+                                             memory_order __order) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedOr16_nf(__a, __value);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedOr16_acq(__a, __value);
+    } else if (__order == memory_order_release) {
+        return _InterlockedOr16_rel(__a, __value);
+    } else {
+        return _InterlockedOr16(__a, __value);
+    }
+#else
+    (void)__order;
+    return _InterlockedOr16(__a, __value);
+#endif
+}
+
+static inline long __msvc_atomic_fetch_or32(volatile long* __a, long __value,
+                                            memory_order __order) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedOr_nf(__a, __value);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedOr_acq(__a, __value);
+    } else if (__order == memory_order_release) {
+        return _InterlockedOr_rel(__a, __value);
+    } else {
+        return _InterlockedOr(__a, __value);
+    }
+#else
+    (void)__order;
+    return _InterlockedOr(__a, __value);
+#endif
+}
+
+static inline __int64 __msvc_atomic_fetch_or64(volatile __int64* __a, __int64 __value,
+                                               memory_order __order) {
+#if defined(_M_IX86)
+    __int64 __tmp;
+    do {
+        __tmp = *__a;
+    } while (__tmp != _InterlockedCompareExchange64(__a, __tmp | __value, __tmp));
+    return __tmp;
+#elif defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedOr64_nf(__a, __value);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedOr64_acq(__a, __value);
+    } else if (__order == memory_order_release) {
+        return _InterlockedOr64_rel(__a, __value);
+    } else {
+        return _InterlockedOr64(__a, __value);
+    }
+#else
+    (void)__order;
+    return _InterlockedOr64(__a, __value);
+#endif
+}
+
+template <typename _Tp>
+static inline _Tp __c11_atomic_fetch_or(volatile _Atomic(_Tp)* __a,
+                                        _Tp __value, int __order) {
+    if (sizeof(_Tp) == 1 && (std::is_integral<_Tp>::value || std::is_same<std::remove_cv_t<_Tp>, bool>::value)) {
+        return __msvc_cast<_Tp>(__msvc_atomic_fetch_or8((volatile char*)__a, __msvc_cast<char>(__value), (memory_order)__order));
+    } else if (sizeof(_Tp) == 2 && std::is_integral<_Tp>::value) {
+        return (_Tp)__msvc_atomic_fetch_or16((volatile short*)__a, (short)__value, (memory_order)__order);
+    } else if (sizeof(_Tp) == 4 && std::is_integral<_Tp>::value) {
+        return (_Tp) __msvc_atomic_fetch_or32((volatile long*)__a, (long)__value, (memory_order)__order);
+    } else if (sizeof(_Tp) == 8 && std::is_integral<_Tp>::value) {
+        return (_Tp) __msvc_atomic_fetch_or64((volatile __int64*)__a, (__int64)__value, (memory_order)__order);
+    } else {
+        __msvc_lock((void*)__a);
+        _Tp __result = *(_Atomic(_Tp)*)__a;
+        *(_Atomic(_Tp)*)__a |= __value;
+        __msvc_unlock((void*)__a);
+        return __result;
+    }
+}
+
+template <typename _Tp>
+static inline _Tp __c11_atomic_fetch_or(_Atomic(_Tp)* __a,
+                                        _Tp __value, int __order) {
+    return __c11_atomic_fetch_or((volatile _Atomic(_Tp)*)__a, __value, __order);
+}
+
+static inline char __msvc_atomic_fetch_xor8(volatile char* __a, char __value,
+                                            memory_order __order) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedXor8_nf(__a, __value);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedXor8_acq(__a, __value);
+    } else if (__order == memory_order_release) {
+        return _InterlockedXor8_rel(__a, __value);
+    } else {
+        return _InterlockedXor8(__a, __value);
+    }
+#else
+    (void)__order;
+    return _InterlockedXor8(__a, __value);
+#endif
+}
+
+static inline short __msvc_atomic_fetch_xor16(volatile short* __a, short __value,
+                                              memory_order __order) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedXor16_nf(__a, __value);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedXor16_acq(__a, __value);
+    } else if (__order == memory_order_release) {
+        return _InterlockedXor16_rel(__a, __value);
+    } else {
+        return _InterlockedXor16(__a, __value);
+    }
+#else
+    (void)__order;
+    return _InterlockedXor16(__a, __value);
+#endif
+}
+
+static inline long __msvc_atomic_fetch_xor32(volatile long* __a, long __value,
+                                             memory_order __order) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedXor_nf(__a, __value);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedXor_acq(__a, __value);
+    } else if (__order == memory_order_release) {
+        return _InterlockedXor_rel(__a, __value);
+    } else {
+        return _InterlockedXor(__a, __value);
+    }
+#else
+    (void)__order;
+    return _InterlockedXor(__a, __value);
+#endif
+}
+
+static inline __int64 __msvc_atomic_fetch_xor64(volatile __int64* __a, __int64 __value,
+                                                memory_order __order) {
+#if defined(_M_IX86)
+    __int64 __tmp;
+    do {
+        __tmp = *__a;
+    } while (__tmp != _InterlockedCompareExchange64(__a, __tmp ^ __value, __tmp));
+    return __tmp;
+#elif defined(_M_ARM) || defined(_M_ARM64)
+    if (__order == memory_order_relaxed) {
+        return _InterlockedXor64_nf(__a, __value);
+    } else if (__order == memory_order_acquire) {
+        return _InterlockedXor64_acq(__a, __value);
+    } else if (__order == memory_order_release) {
+        return _InterlockedXor64_rel(__a, __value);
+    } else {
+        return _InterlockedXor64(__a, __value);
+    }
+#else
+    (void)__order;
+    return _InterlockedXor64(__a, __value);
+#endif
+}
+
+template <typename _Tp>
+static inline _Tp __c11_atomic_fetch_xor(volatile _Atomic(_Tp)* __a,
+                                         _Tp __value, int __order) {
+    if (sizeof(_Tp) == 1 && (std::is_integral<_Tp>::value || std::is_same<std::remove_cv_t<_Tp>, bool>::value)) {
+        return __msvc_cast<_Tp>(__msvc_atomic_fetch_xor8((volatile char*)__a, __msvc_cast<char>(__value), (memory_order)__order));
+    } else if (sizeof(_Tp) == 2 && std::is_integral<_Tp>::value) {
+        return (_Tp)__msvc_atomic_fetch_xor16((volatile short*)__a, (short)__value, (memory_order)__order);
+    } else if (sizeof(_Tp) == 4 && std::is_integral<_Tp>::value) {
+        return (_Tp) __msvc_atomic_fetch_xor32((volatile long*)__a, (long)__value, (memory_order)__order);
+    } else if (sizeof(_Tp) == 8 && std::is_integral<_Tp>::value) {
+        return (_Tp) __msvc_atomic_fetch_xor64((volatile __int64*)__a, (__int64)__value, (memory_order)__order);
+    } else {
+        __msvc_lock((void*)__a);
+        _Tp __result = *(_Atomic(_Tp)*)__a;
+        *(_Atomic(_Tp)*)__a ^= __value;
+        __msvc_unlock((void*)__a);
+        return __result;
+    }
+}
+
+template <typename _Tp>
+static inline _Tp __c11_atomic_fetch_xor(_Atomic(_Tp)* __a,
+                                         _Tp __value, int __order) {
+    return __c11_atomic_fetch_xor((volatile _Atomic(_Tp)*)__a, __value, __order);
+}
+
+static constexpr bool __atomic_is_lock_free(size_t __size, void*) {
+    return __size <= 8;
+}
+
+static constexpr bool __atomic_always_lock_free(size_t __size, void*) {
+    return __size <= 8;
+}
+
+#define __CLANG_ATOMIC_BOOL_LOCK_FREE 2
+#define __CLANG_ATOMIC_CHAR_LOCK_FREE 2
+#define __CLANG_ATOMIC_CHAR8_T_LOCK_FREE 2
+#define __CLANG_ATOMIC_CHAR16_T_LOCK_FREE 2
+#define __CLANG_ATOMIC_CHAR32_T_LOCK_FREE 2
+#define __CLANG_ATOMIC_WCHAR_T_LOCK_FREE 2
+#define __CLANG_ATOMIC_SHORT_LOCK_FREE 2
+#define __CLANG_ATOMIC_INT_LOCK_FREE 2
+#define __CLANG_ATOMIC_LONG_LOCK_FREE 2
+#define __CLANG_ATOMIC_LLONG_LOCK_FREE 2
+#define __CLANG_ATOMIC_POINTER_LOCK_FREE 2
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/win32/limits_msvc_win32.h b/contrib/libs/cxxsupp/libcxx/include/__support/win32/limits_msvc_win32.h
new file mode 100644
index 00000000000..d0903357da3
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/win32/limits_msvc_win32.h
@@ -0,0 +1,70 @@
+// -*- C++ -*-
+//===-----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_WIN32_LIMITS_MSVC_WIN32_H
+#define _LIBCPP_SUPPORT_WIN32_LIMITS_MSVC_WIN32_H
+
+#if !defined(_LIBCPP_MSVCRT)
+#error "This header complements the Microsoft C Runtime library, and should not be included otherwise."
+#endif
+#if defined(__clang__)
+#error "This header should only be included when using Microsofts C1XX frontend"
+#endif
+
+#include <float.h> // limit constants
+#include <limits.h> // CHAR_BIT
+#include <math.h> // HUGE_VAL
+
+#define __CHAR_BIT__       CHAR_BIT
+
+#define __FLT_MANT_DIG__   FLT_MANT_DIG
+#define __FLT_DIG__        FLT_DIG
+#define __FLT_RADIX__      FLT_RADIX
+#define __FLT_MIN_EXP__    FLT_MIN_EXP
+#define __FLT_MIN_10_EXP__ FLT_MIN_10_EXP
+#define __FLT_MAX_EXP__    FLT_MAX_EXP
+#define __FLT_MAX_10_EXP__ FLT_MAX_10_EXP
+#define __FLT_MIN__        FLT_MIN
+#define __FLT_MAX__        FLT_MAX
+#define __FLT_EPSILON__    FLT_EPSILON
+// predefined by MinGW GCC
+#define __FLT_DENORM_MIN__ 1.40129846432481707092e-45F
+
+#define __DBL_MANT_DIG__   DBL_MANT_DIG
+#define __DBL_DIG__        DBL_DIG
+#define __DBL_RADIX__      DBL_RADIX
+#define __DBL_MIN_EXP__    DBL_MIN_EXP
+#define __DBL_MIN_10_EXP__ DBL_MIN_10_EXP
+#define __DBL_MAX_EXP__    DBL_MAX_EXP
+#define __DBL_MAX_10_EXP__ DBL_MAX_10_EXP
+#define __DBL_MIN__        DBL_MIN
+#define __DBL_MAX__        DBL_MAX
+#define __DBL_EPSILON__    DBL_EPSILON
+// predefined by MinGW GCC
+#define __DBL_DENORM_MIN__ double(4.94065645841246544177e-324L)
+
+#define __LDBL_MANT_DIG__   LDBL_MANT_DIG
+#define __LDBL_DIG__        LDBL_DIG
+#define __LDBL_RADIX__      LDBL_RADIX
+#define __LDBL_MIN_EXP__    LDBL_MIN_EXP
+#define __LDBL_MIN_10_EXP__ LDBL_MIN_10_EXP
+#define __LDBL_MAX_EXP__    LDBL_MAX_EXP
+#define __LDBL_MAX_10_EXP__ LDBL_MAX_10_EXP
+#define __LDBL_MIN__        LDBL_MIN
+#define __LDBL_MAX__        LDBL_MAX
+#define __LDBL_EPSILON__    LDBL_EPSILON
+// predefined by MinGW GCC
+#define __LDBL_DENORM_MIN__ 3.64519953188247460253e-4951L
+
+// __builtin replacements/workarounds
+#define __builtin_huge_vall()    ((long double)__builtin_huge_val())
+#define __builtin_nanl(__dummy)  ((long double)__builtin_nan(__dummy))
+#define __builtin_nansl(__dummy) ((long double)__builtin_nans(__dummy))
+
+#endif // _LIBCPP_SUPPORT_WIN32_LIMITS_MSVC_WIN32_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/win32/locale_win32.h b/contrib/libs/cxxsupp/libcxx/include/__support/win32/locale_win32.h
new file mode 100644
index 00000000000..69491bf7467
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/win32/locale_win32.h
@@ -0,0 +1,259 @@
+// -*- C++ -*-
+//===-----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_WIN32_LOCALE_WIN32_H
+#define _LIBCPP_SUPPORT_WIN32_LOCALE_WIN32_H
+
+#include <__config>
+#include <__nullptr>
+#include <locale.h> // _locale_t
+#include <stdio.h>
+
+#define _X_ALL LC_ALL
+#define _X_COLLATE LC_COLLATE
+#define _X_CTYPE LC_CTYPE
+#define _X_MONETARY LC_MONETARY
+#define _X_NUMERIC LC_NUMERIC
+#define _X_TIME LC_TIME
+#define _X_MAX LC_MAX
+#define _X_MESSAGES 6
+#define _NCAT (_X_MESSAGES + 1)
+
+#define _CATMASK(n) ((1 << (n)) >> 1)
+#define _M_COLLATE _CATMASK(_X_COLLATE)
+#define _M_CTYPE _CATMASK(_X_CTYPE)
+#define _M_MONETARY _CATMASK(_X_MONETARY)
+#define _M_NUMERIC _CATMASK(_X_NUMERIC)
+#define _M_TIME _CATMASK(_X_TIME)
+#define _M_MESSAGES _CATMASK(_X_MESSAGES)
+#define _M_ALL (_CATMASK(_NCAT) - 1)
+
+#define LC_COLLATE_MASK _M_COLLATE
+#define LC_CTYPE_MASK _M_CTYPE
+#define LC_MONETARY_MASK _M_MONETARY
+#define LC_NUMERIC_MASK _M_NUMERIC
+#define LC_TIME_MASK _M_TIME
+#define LC_MESSAGES_MASK _M_MESSAGES
+#define LC_MESSAGES _X_MESSAGES
+#define LC_ALL_MASK _M_ALL
+
+class __lconv_storage {
+public:
+    __lconv_storage(const lconv *__lc_input) {
+        __lc = *__lc_input;
+
+        __decimal_point = __lc_input->decimal_point;
+        __thousands_sep = __lc_input->thousands_sep;
+        __grouping = __lc_input->grouping;
+        __int_curr_symbol = __lc_input->int_curr_symbol;
+        __currency_symbol = __lc_input->currency_symbol;
+        __mon_decimal_point = __lc_input->mon_decimal_point;
+        __mon_thousands_sep = __lc_input->mon_thousands_sep;
+        __mon_grouping = __lc_input->mon_grouping;
+        __positive_sign = __lc_input->positive_sign;
+        __negative_sign = __lc_input->negative_sign;
+
+        __lc.decimal_point = const_cast<char *>(__decimal_point.c_str());
+        __lc.thousands_sep = const_cast<char *>(__thousands_sep.c_str());
+        __lc.grouping = const_cast<char *>(__grouping.c_str());
+        __lc.int_curr_symbol = const_cast<char *>(__int_curr_symbol.c_str());
+        __lc.currency_symbol = const_cast<char *>(__currency_symbol.c_str());
+        __lc.mon_decimal_point = const_cast<char *>(__mon_decimal_point.c_str());
+        __lc.mon_thousands_sep = const_cast<char *>(__mon_thousands_sep.c_str());
+        __lc.mon_grouping = const_cast<char *>(__mon_grouping.c_str());
+        __lc.positive_sign = const_cast<char *>(__positive_sign.c_str());
+        __lc.negative_sign = const_cast<char *>(__negative_sign.c_str());
+    }
+
+    lconv *__get() {
+        return &__lc;
+    }
+private:
+    lconv __lc;
+    std::string __decimal_point;
+    std::string __thousands_sep;
+    std::string __grouping;
+    std::string __int_curr_symbol;
+    std::string __currency_symbol;
+    std::string __mon_decimal_point;
+    std::string __mon_thousands_sep;
+    std::string __mon_grouping;
+    std::string __positive_sign;
+    std::string __negative_sign;
+};
+
+class locale_t {
+public:
+    locale_t()
+        : __locale(nullptr), __locale_str(nullptr), __lc(nullptr) {}
+    locale_t(std::nullptr_t)
+        : __locale(nullptr), __locale_str(nullptr), __lc(nullptr) {}
+    locale_t(_locale_t __xlocale, const char* __xlocale_str)
+        : __locale(__xlocale), __locale_str(__xlocale_str), __lc(nullptr) {}
+    locale_t(const locale_t &__l)
+        : __locale(__l.__locale), __locale_str(__l.__locale_str), __lc(nullptr) {}
+
+    ~locale_t() {
+        delete __lc;
+    }
+
+    locale_t &operator =(const locale_t &__l) {
+        __locale = __l.__locale;
+        __locale_str = __l.__locale_str;
+        // __lc not copied
+        return *this;
+    }
+
+    friend bool operator==(const locale_t& __left, const locale_t& __right) {
+        return __left.__locale == __right.__locale;
+    }
+
+    friend bool operator==(const locale_t& __left, int __right) {
+        return __left.__locale == nullptr && __right == 0;
+    }
+
+    friend bool operator==(const locale_t& __left, long long __right) {
+        return __left.__locale == nullptr && __right == 0;
+    }
+
+    friend bool operator==(const locale_t& __left, std::nullptr_t) {
+        return __left.__locale == nullptr;
+    }
+
+    friend bool operator==(int __left, const locale_t& __right) {
+        return __left == 0 && nullptr == __right.__locale;
+    }
+
+    friend bool operator==(std::nullptr_t, const locale_t& __right) {
+        return nullptr == __right.__locale;
+    }
+
+    friend bool operator!=(const locale_t& __left, const locale_t& __right) {
+        return !(__left == __right);
+    }
+
+    friend bool operator!=(const locale_t& __left, int __right) {
+        return !(__left == __right);
+    }
+
+    friend bool operator!=(const locale_t& __left, long long __right) {
+        return !(__left == __right);
+    }
+
+    friend bool operator!=(const locale_t& __left, std::nullptr_t __right) {
+        return !(__left == __right);
+    }
+
+    friend bool operator!=(int __left, const locale_t& __right) {
+        return !(__left == __right);
+    }
+
+    friend bool operator!=(std::nullptr_t __left, const locale_t& __right) {
+        return !(__left == __right);
+    }
+
+    operator bool() const {
+        return __locale != nullptr;
+    }
+
+    const char* __get_locale() const { return __locale_str; }
+
+    operator _locale_t() const {
+        return __locale;
+    }
+
+    lconv *__store_lconv(const lconv *__input_lc) {
+        delete __lc;
+        __lc = new __lconv_storage(__input_lc);
+        return __lc->__get();
+    }
+private:
+    _locale_t __locale;
+    const char* __locale_str;
+    __lconv_storage *__lc = nullptr;
+};
+
+// Locale management functions
+#define freelocale _free_locale
+// FIXME: base currently unused. Needs manual work to construct the new locale
+locale_t newlocale( int mask, const char * locale, locale_t base );
+// uselocale can't be implemented on Windows because Windows allows partial modification
+// of thread-local locale and so _get_current_locale() returns a copy while uselocale does
+// not create any copies.
+// We can still implement raii even without uselocale though.
+
+
+lconv *localeconv_l( locale_t &__loc );
+size_t mbrlen_l( const char *__restrict __s, size_t __n,
+                 mbstate_t *__restrict __ps, locale_t __loc);
+size_t mbsrtowcs_l( wchar_t *__restrict __dst, const char **__restrict __src,
+                    size_t __len, mbstate_t *__restrict __ps, locale_t __loc );
+size_t wcrtomb_l( char *__restrict s, wchar_t __wc, mbstate_t *__restrict __ps,
+                  locale_t __loc);
+size_t mbrtowc_l( wchar_t *__restrict __pwc, const char *__restrict __s,
+                  size_t __n, mbstate_t *__restrict __ps, locale_t __loc);
+size_t mbsnrtowcs_l( wchar_t *__restrict __dst, const char **__restrict __src,
+                     size_t __nms, size_t __len, mbstate_t *__restrict __ps, locale_t __loc);
+size_t wcsnrtombs_l( char *__restrict __dst, const wchar_t **__restrict __src,
+                     size_t __nwc, size_t __len, mbstate_t *__restrict __ps, locale_t __loc);
+wint_t btowc_l( int __c, locale_t __loc );
+int wctob_l( wint_t __c, locale_t __loc );
+
+decltype(MB_CUR_MAX) MB_CUR_MAX_L( locale_t __l );
+
+// the *_l functions are prefixed on Windows, only available for msvcr80+, VS2005+
+#define mbtowc_l _mbtowc_l
+#define strtoll_l _strtoi64_l
+#define strtoull_l _strtoui64_l
+#define strtod_l _strtod_l
+#if defined(_LIBCPP_MSVCRT)
+#define strtof_l _strtof_l
+#define strtold_l _strtod_l
+#else
+_LIBCPP_FUNC_VIS float strtof_l(const char*, char**, locale_t);
+_LIBCPP_FUNC_VIS long double strtold_l(const char*, char**, locale_t);
+#endif
+#define isupper_l _isupper_l
+#define islower_l _islower_l
+#define isblank_l _isblank_l
+#define isdigit_l _isdigit_l
+#define isxdigit_l _isxdigit_l
+#define strcoll_l _strcoll_l
+#define strxfrm_l _strxfrm_l
+#define wcscoll_l _wcscoll_l
+#define wcsxfrm_l _wcsxfrm_l
+#define toupper_l _toupper_l
+#define tolower_l _tolower_l
+#define iswspace_l _iswspace_l
+#define iswprint_l _iswprint_l
+#define iswcntrl_l _iswcntrl_l
+#define iswupper_l _iswupper_l
+#define iswlower_l _iswlower_l
+#define iswblank_l _iswblank_l
+#define iswalpha_l _iswalpha_l
+#define iswdigit_l _iswdigit_l
+#define iswpunct_l _iswpunct_l
+#define iswxdigit_l _iswxdigit_l
+#define towupper_l _towupper_l
+#define towlower_l _towlower_l
+#if defined(__MINGW32__) && __MSVCRT_VERSION__ < 0x0800
+_LIBCPP_FUNC_VIS size_t strftime_l(char *ret, size_t n, const char *format,
+                                   const struct tm *tm, locale_t loc);
+#else
+#define strftime_l _strftime_l
+#endif
+#define sscanf_l( __s, __l, __f, ...) _sscanf_l( __s, __f, __l, ##__VA_ARGS__ )
+#define sprintf_l( __s, __l, __f, ... ) _sprintf_l( __s, __f, __l, ##__VA_ARGS__ )
+#define vsprintf_l( __s, __l, __f, ... ) _vsprintf_l( __s, __f, __l, ##__VA_ARGS__ )
+#define vsnprintf_l( __s, __n, __l, __f, ... ) _vsnprintf_l( __s, __n, __f, __l, ##__VA_ARGS__ )
+#define snprintf_l(__s, __n, __l, __f, ...) _snprintf_l( __s, __n, __f, __l, ##__VA_ARGS__ )
+_LIBCPP_FUNC_VIS int asprintf_l( char **__ret, locale_t __loc, const char *__format, ... );
+_LIBCPP_FUNC_VIS int vasprintf_l( char **__ret, locale_t __loc, const char *__format, va_list __ap );
+
+#endif // _LIBCPP_SUPPORT_WIN32_LOCALE_WIN32_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/xlocale/__nop_locale_mgmt.h b/contrib/libs/cxxsupp/libcxx/include/__support/xlocale/__nop_locale_mgmt.h
new file mode 100644
index 00000000000..57b18842ff4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/xlocale/__nop_locale_mgmt.h
@@ -0,0 +1,51 @@
+// -*- C++ -*-
+//===-----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_XLOCALE_NOP_LOCALE_MGMT_H
+#define _LIBCPP_SUPPORT_XLOCALE_NOP_LOCALE_MGMT_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Patch over lack of extended locale support
+typedef void *locale_t;
+static inline locale_t duplocale(locale_t) {
+  return NULL;
+}
+
+static inline void freelocale(locale_t) {
+}
+
+static inline locale_t newlocale(int, const char *, locale_t) {
+  return NULL;
+}
+
+static inline locale_t uselocale(locale_t) {
+  return NULL;
+}
+
+#define LC_COLLATE_MASK  (1 << LC_COLLATE)
+#define LC_CTYPE_MASK    (1 << LC_CTYPE)
+#define LC_MESSAGES_MASK (1 << LC_MESSAGES)
+#define LC_MONETARY_MASK (1 << LC_MONETARY)
+#define LC_NUMERIC_MASK  (1 << LC_NUMERIC)
+#define LC_TIME_MASK     (1 << LC_TIME)
+#define LC_ALL_MASK (LC_COLLATE_MASK|\
+                     LC_CTYPE_MASK|\
+                     LC_MONETARY_MASK|\
+                     LC_NUMERIC_MASK|\
+                     LC_TIME_MASK|\
+                     LC_MESSAGES_MASK)
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif // _LIBCPP_SUPPORT_XLOCALE_NOP_LOCALE_MGMT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/xlocale/__posix_l_fallback.h b/contrib/libs/cxxsupp/libcxx/include/__support/xlocale/__posix_l_fallback.h
new file mode 100644
index 00000000000..00d69d19e8c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/xlocale/__posix_l_fallback.h
@@ -0,0 +1,164 @@
+// -*- C++ -*-
+//===-----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// These are reimplementations of some extended locale functions ( *_l ) that
+// are normally part of POSIX.  This shared implementation provides parts of the
+// extended locale support for libc's that normally don't have any (like
+// Android's bionic and Newlib).
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_XLOCALE_POSIX_L_FALLBACK_H
+#define _LIBCPP_SUPPORT_XLOCALE_POSIX_L_FALLBACK_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+inline _LIBCPP_INLINE_VISIBILITY int isalnum_l(int c, locale_t) {
+  return ::isalnum(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int isalpha_l(int c, locale_t) {
+  return ::isalpha(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int isblank_l(int c, locale_t) {
+  return ::isblank(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int iscntrl_l(int c, locale_t) {
+  return ::iscntrl(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int isdigit_l(int c, locale_t) {
+  return ::isdigit(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int isgraph_l(int c, locale_t) {
+  return ::isgraph(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int islower_l(int c, locale_t) {
+  return ::islower(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int isprint_l(int c, locale_t) {
+  return ::isprint(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int ispunct_l(int c, locale_t) {
+  return ::ispunct(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int isspace_l(int c, locale_t) {
+  return ::isspace(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int isupper_l(int c, locale_t) {
+  return ::isupper(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int isxdigit_l(int c, locale_t) {
+  return ::isxdigit(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int iswalnum_l(wint_t c, locale_t) {
+  return ::iswalnum(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int iswalpha_l(wint_t c, locale_t) {
+  return ::iswalpha(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int iswblank_l(wint_t c, locale_t) {
+  return ::iswblank(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int iswcntrl_l(wint_t c, locale_t) {
+  return ::iswcntrl(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int iswdigit_l(wint_t c, locale_t) {
+  return ::iswdigit(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int iswgraph_l(wint_t c, locale_t) {
+  return ::iswgraph(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int iswlower_l(wint_t c, locale_t) {
+  return ::iswlower(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int iswprint_l(wint_t c, locale_t) {
+  return ::iswprint(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int iswpunct_l(wint_t c, locale_t) {
+  return ::iswpunct(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int iswspace_l(wint_t c, locale_t) {
+  return ::iswspace(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int iswupper_l(wint_t c, locale_t) {
+  return ::iswupper(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int iswxdigit_l(wint_t c, locale_t) {
+  return ::iswxdigit(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int toupper_l(int c, locale_t) {
+  return ::toupper(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int tolower_l(int c, locale_t) {
+  return ::tolower(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY wint_t towupper_l(wint_t c, locale_t) {
+  return ::towupper(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY wint_t towlower_l(wint_t c, locale_t) {
+  return ::towlower(c);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int strcoll_l(const char *s1, const char *s2,
+                                               locale_t) {
+  return ::strcoll(s1, s2);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY size_t strxfrm_l(char *dest, const char *src,
+                                                  size_t n, locale_t) {
+  return ::strxfrm(dest, src, n);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY size_t strftime_l(char *s, size_t max,
+                                                   const char *format,
+                                                   const struct tm *tm, locale_t) {
+  return ::strftime(s, max, format, tm);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY int wcscoll_l(const wchar_t *ws1,
+                                               const wchar_t *ws2, locale_t) {
+  return ::wcscoll(ws1, ws2);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY size_t wcsxfrm_l(wchar_t *dest, const wchar_t *src,
+                                                  size_t n, locale_t) {
+  return ::wcsxfrm(dest, src, n);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _LIBCPP_SUPPORT_XLOCALE_POSIX_L_FALLBACK_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__support/xlocale/__strtonum_fallback.h b/contrib/libs/cxxsupp/libcxx/include/__support/xlocale/__strtonum_fallback.h
new file mode 100644
index 00000000000..1172a5d5723
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__support/xlocale/__strtonum_fallback.h
@@ -0,0 +1,66 @@
+// -*- C++ -*-
+//===-----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// These are reimplementations of some extended locale functions ( *_l ) that
+// aren't part of POSIX.  They are widely available though (GLIBC, BSD, maybe
+// others).  The unifying aspect in this case is that all of these functions
+// convert strings to some numeric type.
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SUPPORT_XLOCALE_STRTONUM_FALLBACK_H
+#define _LIBCPP_SUPPORT_XLOCALE_STRTONUM_FALLBACK_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+inline _LIBCPP_INLINE_VISIBILITY float strtof_l(const char *nptr,
+                                                char **endptr, locale_t) {
+  return ::strtof(nptr, endptr);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY double strtod_l(const char *nptr,
+                                                 char **endptr, locale_t) {
+  return ::strtod(nptr, endptr);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY long double strtold_l(const char *nptr,
+                                                       char **endptr, locale_t) {
+  return ::strtold(nptr, endptr);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY long long
+strtoll_l(const char *nptr, char **endptr, int base, locale_t) {
+  return ::strtoll(nptr, endptr, base);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY unsigned long long
+strtoull_l(const char *nptr, char **endptr, int base, locale_t) {
+  return ::strtoull(nptr, endptr, base);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY long long
+wcstoll_l(const wchar_t *nptr, wchar_t **endptr, int base, locale_t) {
+  return ::wcstoll(nptr, endptr, base);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY unsigned long long
+wcstoull_l(const wchar_t *nptr, wchar_t **endptr, int base, locale_t) {
+  return ::wcstoull(nptr, endptr, base);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY long double wcstold_l(const wchar_t *nptr,
+                                                       wchar_t **endptr, locale_t) {
+  return ::wcstold(nptr, endptr);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _LIBCPP_SUPPORT_XLOCALE_STRTONUM_FALLBACK_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__threading_support b/contrib/libs/cxxsupp/libcxx/include/__threading_support
new file mode 100644
index 00000000000..9b0de00dfcb
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__threading_support
@@ -0,0 +1,819 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_THREADING_SUPPORT
+#define _LIBCPP_THREADING_SUPPORT
+
+#include <__availability>
+#include <__config>
+#include <chrono>
+#include <errno.h>
+#include <iosfwd>
+#include <limits>
+
+#ifdef __MVS__
+# include <__support/ibm/nanosleep.h>
+#endif
+
+#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
+#pragma GCC system_header
+#endif
+
+#if defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
+# define _LIBCPP_EXTERNAL_THREADING <__external_threading>
+# include _LIBCPP_EXTERNAL_THREADING
+# undef _LIBCPP_EXTERNAL_THREADING
+#elif !defined(_LIBCPP_HAS_NO_THREADS)
+
+#if defined(__APPLE__) || defined(__MVS__)
+# define _LIBCPP_NO_NATIVE_SEMAPHORES
+#endif
+
+#if defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
+# include <pthread.h>
+# include <sched.h>
+# ifndef _LIBCPP_NO_NATIVE_SEMAPHORES
+#   include <semaphore.h>
+# endif
+#elif defined(_LIBCPP_HAS_THREAD_API_C11)
+# include <threads.h>
+#endif
+
+#if defined(_LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL) || \
+    defined(_LIBCPP_BUILDING_THREAD_LIBRARY_EXTERNAL) || \
+    defined(_LIBCPP_HAS_THREAD_API_WIN32)
+#define _LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_FUNC_VIS
+#else
+#define _LIBCPP_THREAD_ABI_VISIBILITY inline _LIBCPP_INLINE_VISIBILITY
+#endif
+
+#if defined(__FreeBSD__) && defined(__clang__) && __has_attribute(no_thread_safety_analysis)
+#define _LIBCPP_NO_THREAD_SAFETY_ANALYSIS __attribute__((no_thread_safety_analysis))
+#else
+#define _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
+#endif
+
+typedef ::timespec __libcpp_timespec_t;
+#endif // !defined(_LIBCPP_HAS_NO_THREADS)
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_THREADS)
+
+#if defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
+// Mutex
+typedef pthread_mutex_t __libcpp_mutex_t;
+#define _LIBCPP_MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER
+
+typedef pthread_mutex_t __libcpp_recursive_mutex_t;
+
+// Condition Variable
+typedef pthread_cond_t __libcpp_condvar_t;
+#define _LIBCPP_CONDVAR_INITIALIZER PTHREAD_COND_INITIALIZER
+
+#ifndef _LIBCPP_NO_NATIVE_SEMAPHORES
+// Semaphore
+typedef sem_t __libcpp_semaphore_t;
+# define _LIBCPP_SEMAPHORE_MAX SEM_VALUE_MAX
+#endif
+
+// Execute once
+typedef pthread_once_t __libcpp_exec_once_flag;
+#define _LIBCPP_EXEC_ONCE_INITIALIZER PTHREAD_ONCE_INIT
+
+// Thread id
+#if defined(__MVS__)
+  typedef unsigned long long __libcpp_thread_id;
+#else
+  typedef pthread_t __libcpp_thread_id;
+#endif
+
+// Thread
+#define _LIBCPP_NULL_THREAD ((__libcpp_thread_t()))
+typedef pthread_t __libcpp_thread_t;
+
+// Thread Local Storage
+typedef pthread_key_t __libcpp_tls_key;
+
+#define _LIBCPP_TLS_DESTRUCTOR_CC
+#elif defined(_LIBCPP_HAS_THREAD_API_C11)
+// Mutex
+typedef mtx_t __libcpp_mutex_t;
+// mtx_t is a struct so using {} for initialization is valid.
+#define _LIBCPP_MUTEX_INITIALIZER {}
+
+typedef mtx_t __libcpp_recursive_mutex_t;
+
+// Condition Variable
+typedef cnd_t __libcpp_condvar_t;
+// cnd_t is a struct so using {} for initialization is valid.
+#define _LIBCPP_CONDVAR_INITIALIZER {}
+
+// Execute once
+typedef once_flag __libcpp_exec_once_flag;
+#define _LIBCPP_EXEC_ONCE_INITIALIZER ONCE_FLAG_INIT
+
+// Thread id
+typedef thrd_t __libcpp_thread_id;
+
+// Thread
+#define _LIBCPP_NULL_THREAD 0U
+
+typedef thrd_t __libcpp_thread_t;
+
+// Thread Local Storage
+typedef tss_t __libcpp_tls_key;
+
+#define _LIBCPP_TLS_DESTRUCTOR_CC
+#elif !defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
+// Mutex
+typedef void* __libcpp_mutex_t;
+#define _LIBCPP_MUTEX_INITIALIZER 0
+
+#if defined(_M_IX86) || defined(__i386__) || defined(_M_ARM) || defined(__arm__)
+typedef void* __libcpp_recursive_mutex_t[6];
+#elif defined(_M_AMD64) || defined(__x86_64__) || defined(_M_ARM64) || defined(__aarch64__)
+typedef void* __libcpp_recursive_mutex_t[5];
+#else
+# error Unsupported architecture
+#endif
+
+// Condition Variable
+typedef void* __libcpp_condvar_t;
+#define _LIBCPP_CONDVAR_INITIALIZER 0
+
+// Semaphore
+typedef void* __libcpp_semaphore_t;
+#if defined(_LIBCPP_HAS_THREAD_API_WIN32)
+# define _LIBCPP_SEMAPHORE_MAX (::std::numeric_limits<long>::max())
+#endif
+
+// Execute Once
+typedef void* __libcpp_exec_once_flag;
+#define _LIBCPP_EXEC_ONCE_INITIALIZER 0
+
+// Thread ID
+typedef long __libcpp_thread_id;
+
+// Thread
+#define _LIBCPP_NULL_THREAD 0U
+
+typedef void* __libcpp_thread_t;
+
+// Thread Local Storage
+typedef long __libcpp_tls_key;
+
+#define _LIBCPP_TLS_DESTRUCTOR_CC __stdcall
+#endif // !defined(_LIBCPP_HAS_THREAD_API_PTHREAD) && !defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
+
+#if !defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
+// Mutex
+_LIBCPP_THREAD_ABI_VISIBILITY
+int __libcpp_recursive_mutex_init(__libcpp_recursive_mutex_t *__m);
+
+_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
+int __libcpp_recursive_mutex_lock(__libcpp_recursive_mutex_t *__m);
+
+_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
+bool __libcpp_recursive_mutex_trylock(__libcpp_recursive_mutex_t *__m);
+
+_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
+int __libcpp_recursive_mutex_unlock(__libcpp_recursive_mutex_t *__m);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+int __libcpp_recursive_mutex_destroy(__libcpp_recursive_mutex_t *__m);
+
+_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
+int __libcpp_mutex_lock(__libcpp_mutex_t *__m);
+
+_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
+bool __libcpp_mutex_trylock(__libcpp_mutex_t *__m);
+
+_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
+int __libcpp_mutex_unlock(__libcpp_mutex_t *__m);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+int __libcpp_mutex_destroy(__libcpp_mutex_t *__m);
+
+// Condition variable
+_LIBCPP_THREAD_ABI_VISIBILITY
+int __libcpp_condvar_signal(__libcpp_condvar_t* __cv);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+int __libcpp_condvar_broadcast(__libcpp_condvar_t* __cv);
+
+_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
+int __libcpp_condvar_wait(__libcpp_condvar_t* __cv, __libcpp_mutex_t* __m);
+
+_LIBCPP_THREAD_ABI_VISIBILITY _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
+int __libcpp_condvar_timedwait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m,
+                               __libcpp_timespec_t *__ts);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+int __libcpp_condvar_destroy(__libcpp_condvar_t* __cv);
+
+#ifndef _LIBCPP_NO_NATIVE_SEMAPHORES
+
+// Semaphore
+_LIBCPP_THREAD_ABI_VISIBILITY
+bool __libcpp_semaphore_init(__libcpp_semaphore_t* __sem, int __init);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+bool __libcpp_semaphore_destroy(__libcpp_semaphore_t* __sem);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+bool __libcpp_semaphore_post(__libcpp_semaphore_t* __sem);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+bool __libcpp_semaphore_wait(__libcpp_semaphore_t* __sem);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+bool __libcpp_semaphore_wait_timed(__libcpp_semaphore_t* __sem, chrono::nanoseconds const& __ns);
+
+#endif // _LIBCPP_NO_NATIVE_SEMAPHORES
+
+// Execute once
+_LIBCPP_THREAD_ABI_VISIBILITY
+int __libcpp_execute_once(__libcpp_exec_once_flag *flag,
+                          void (*init_routine)());
+
+// Thread id
+_LIBCPP_THREAD_ABI_VISIBILITY
+bool __libcpp_thread_id_equal(__libcpp_thread_id t1, __libcpp_thread_id t2);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+bool __libcpp_thread_id_less(__libcpp_thread_id t1, __libcpp_thread_id t2);
+
+// Thread
+_LIBCPP_THREAD_ABI_VISIBILITY
+bool __libcpp_thread_isnull(const __libcpp_thread_t *__t);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+int __libcpp_thread_create(__libcpp_thread_t *__t, void *(*__func)(void *),
+                           void *__arg);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+__libcpp_thread_id __libcpp_thread_get_current_id();
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+__libcpp_thread_id __libcpp_thread_get_id(const __libcpp_thread_t *__t);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+int __libcpp_thread_join(__libcpp_thread_t *__t);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+int __libcpp_thread_detach(__libcpp_thread_t *__t);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+void __libcpp_thread_yield();
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+void __libcpp_thread_sleep_for(const chrono::nanoseconds& __ns);
+
+// Thread local storage
+_LIBCPP_THREAD_ABI_VISIBILITY
+int __libcpp_tls_create(__libcpp_tls_key* __key,
+                        void(_LIBCPP_TLS_DESTRUCTOR_CC* __at_exit)(void*));
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+void *__libcpp_tls_get(__libcpp_tls_key __key);
+
+_LIBCPP_THREAD_ABI_VISIBILITY
+int __libcpp_tls_set(__libcpp_tls_key __key, void *__p);
+
+#endif // !defined(_LIBCPP_HAS_THREAD_API_EXTERNAL)
+
+struct __libcpp_timed_backoff_policy {
+  _LIBCPP_INLINE_VISIBILITY
+  bool operator()(chrono::nanoseconds __elapsed) const
+  {
+      if(__elapsed > chrono::milliseconds(128))
+          __libcpp_thread_sleep_for(chrono::milliseconds(8));
+      else if(__elapsed > chrono::microseconds(64))
+          __libcpp_thread_sleep_for(__elapsed / 2);
+      else if(__elapsed > chrono::microseconds(4))
+        __libcpp_thread_yield();
+      else
+        {} // poll
+      return false;
+  }
+};
+
+static _LIBCPP_CONSTEXPR const int __libcpp_polling_count = 64;
+
+template<class _Fn, class _BFn>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+bool __libcpp_thread_poll_with_backoff(
+  _Fn && __f, _BFn && __bf, chrono::nanoseconds __max_elapsed = chrono::nanoseconds::zero())
+{
+    auto const __start = chrono::high_resolution_clock::now();
+    for(int __count = 0;;) {
+      if(__f())
+        return true; // _Fn completion means success
+      if(__count < __libcpp_polling_count) {
+        __count += 1;
+        continue;
+      }
+      chrono::nanoseconds const __elapsed = chrono::high_resolution_clock::now() - __start;
+      if(__max_elapsed != chrono::nanoseconds::zero() && __max_elapsed < __elapsed)
+          return false; // timeout failure
+      if(__bf(__elapsed))
+        return false; // _BFn completion means failure
+    }
+}
+
+#if (!defined(_LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL) || \
+     defined(_LIBCPP_BUILDING_THREAD_LIBRARY_EXTERNAL))
+
+
+namespace __thread_detail {
+
+inline __libcpp_timespec_t __convert_to_timespec(const chrono::nanoseconds& __ns)
+{
+  using namespace chrono;
+  seconds __s = duration_cast<seconds>(__ns);
+  __libcpp_timespec_t __ts;
+  typedef decltype(__ts.tv_sec) __ts_sec;
+  const __ts_sec __ts_sec_max = numeric_limits<__ts_sec>::max();
+
+  if (__s.count() < __ts_sec_max)
+  {
+    __ts.tv_sec = static_cast<__ts_sec>(__s.count());
+    __ts.tv_nsec = static_cast<decltype(__ts.tv_nsec)>((__ns - __s).count());
+  }
+  else
+  {
+    __ts.tv_sec = __ts_sec_max;
+    __ts.tv_nsec = 999999999; // (10^9 - 1)
+  }
+
+  return __ts;
+}
+
+}
+
+#if defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
+
+int __libcpp_recursive_mutex_init(__libcpp_recursive_mutex_t *__m)
+{
+  pthread_mutexattr_t attr;
+  int __ec = pthread_mutexattr_init(&attr);
+  if (__ec)
+    return __ec;
+  __ec = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
+  if (__ec) {
+    pthread_mutexattr_destroy(&attr);
+    return __ec;
+  }
+  __ec = pthread_mutex_init(__m, &attr);
+  if (__ec) {
+    pthread_mutexattr_destroy(&attr);
+    return __ec;
+  }
+  __ec = pthread_mutexattr_destroy(&attr);
+  if (__ec) {
+    pthread_mutex_destroy(__m);
+    return __ec;
+  }
+  return 0;
+}
+
+int __libcpp_recursive_mutex_lock(__libcpp_recursive_mutex_t *__m)
+{
+  return pthread_mutex_lock(__m);
+}
+
+bool __libcpp_recursive_mutex_trylock(__libcpp_recursive_mutex_t *__m)
+{
+  return pthread_mutex_trylock(__m) == 0;
+}
+
+int __libcpp_recursive_mutex_unlock(__libcpp_recursive_mutex_t *__m)
+{
+  return pthread_mutex_unlock(__m);
+}
+
+int __libcpp_recursive_mutex_destroy(__libcpp_recursive_mutex_t *__m)
+{
+  return pthread_mutex_destroy(__m);
+}
+
+int __libcpp_mutex_lock(__libcpp_mutex_t *__m)
+{
+  return pthread_mutex_lock(__m);
+}
+
+bool __libcpp_mutex_trylock(__libcpp_mutex_t *__m)
+{
+  return pthread_mutex_trylock(__m) == 0;
+}
+
+int __libcpp_mutex_unlock(__libcpp_mutex_t *__m)
+{
+  return pthread_mutex_unlock(__m);
+}
+
+int __libcpp_mutex_destroy(__libcpp_mutex_t *__m)
+{
+  return pthread_mutex_destroy(__m);
+}
+
+// Condition Variable
+int __libcpp_condvar_signal(__libcpp_condvar_t *__cv)
+{
+  return pthread_cond_signal(__cv);
+}
+
+int __libcpp_condvar_broadcast(__libcpp_condvar_t *__cv)
+{
+  return pthread_cond_broadcast(__cv);
+}
+
+int __libcpp_condvar_wait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m)
+{
+  return pthread_cond_wait(__cv, __m);
+}
+
+int __libcpp_condvar_timedwait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m,
+                               __libcpp_timespec_t *__ts)
+{
+  return pthread_cond_timedwait(__cv, __m, __ts);
+}
+
+int __libcpp_condvar_destroy(__libcpp_condvar_t *__cv)
+{
+  return pthread_cond_destroy(__cv);
+}
+
+#ifndef _LIBCPP_NO_NATIVE_SEMAPHORES
+
+// Semaphore
+bool __libcpp_semaphore_init(__libcpp_semaphore_t* __sem, int __init)
+{
+    return sem_init(__sem, 0, __init) == 0;
+}
+
+bool __libcpp_semaphore_destroy(__libcpp_semaphore_t* __sem)
+{
+    return sem_destroy(__sem) == 0;
+}
+
+bool __libcpp_semaphore_post(__libcpp_semaphore_t* __sem)
+{
+    return sem_post(__sem) == 0;
+}
+
+bool __libcpp_semaphore_wait(__libcpp_semaphore_t* __sem)
+{
+    return sem_wait(__sem) == 0;
+}
+
+bool __libcpp_semaphore_wait_timed(__libcpp_semaphore_t* __sem, chrono::nanoseconds const& __ns)
+{
+    auto const __abs_time = chrono::system_clock::now().time_since_epoch() + __ns;
+    __libcpp_timespec_t __ts = __thread_detail::__convert_to_timespec(__abs_time);
+    return sem_timedwait(__sem, &__ts) == 0;
+}
+
+#endif //_LIBCPP_NO_NATIVE_SEMAPHORES
+
+// Execute once
+int __libcpp_execute_once(__libcpp_exec_once_flag *flag,
+                          void (*init_routine)()) {
+  return pthread_once(flag, init_routine);
+}
+
+// Thread id
+// Returns non-zero if the thread ids are equal, otherwise 0
+bool __libcpp_thread_id_equal(__libcpp_thread_id t1, __libcpp_thread_id t2)
+{
+  return t1 == t2;
+}
+
+// Returns non-zero if t1 < t2, otherwise 0
+bool __libcpp_thread_id_less(__libcpp_thread_id t1, __libcpp_thread_id t2)
+{
+  return t1 < t2;
+}
+
+// Thread
+bool __libcpp_thread_isnull(const __libcpp_thread_t *__t) {
+  return __libcpp_thread_get_id(__t) == 0;
+}
+
+int __libcpp_thread_create(__libcpp_thread_t *__t, void *(*__func)(void *),
+                           void *__arg)
+{
+  return pthread_create(__t, nullptr, __func, __arg);
+}
+
+__libcpp_thread_id __libcpp_thread_get_current_id()
+{
+  const __libcpp_thread_t thread = pthread_self();
+  return __libcpp_thread_get_id(&thread);
+}
+
+__libcpp_thread_id __libcpp_thread_get_id(const __libcpp_thread_t *__t)
+{
+#if defined(__MVS__)
+  return __t->__;
+#else
+  return *__t;
+#endif
+}
+
+int __libcpp_thread_join(__libcpp_thread_t *__t)
+{
+  return pthread_join(*__t, nullptr);
+}
+
+int __libcpp_thread_detach(__libcpp_thread_t *__t)
+{
+  return pthread_detach(*__t);
+}
+
+void __libcpp_thread_yield()
+{
+  sched_yield();
+}
+
+void __libcpp_thread_sleep_for(const chrono::nanoseconds& __ns)
+{
+   __libcpp_timespec_t __ts = __thread_detail::__convert_to_timespec(__ns);
+   while (nanosleep(&__ts, &__ts) == -1 && errno == EINTR);
+}
+
+// Thread local storage
+int __libcpp_tls_create(__libcpp_tls_key *__key, void (*__at_exit)(void *))
+{
+  return pthread_key_create(__key, __at_exit);
+}
+
+void *__libcpp_tls_get(__libcpp_tls_key __key)
+{
+  return pthread_getspecific(__key);
+}
+
+int __libcpp_tls_set(__libcpp_tls_key __key, void *__p)
+{
+    return pthread_setspecific(__key, __p);
+}
+
+#elif defined(_LIBCPP_HAS_THREAD_API_C11)
+
+int __libcpp_recursive_mutex_init(__libcpp_recursive_mutex_t *__m)
+{
+  return mtx_init(__m, mtx_plain | mtx_recursive) == thrd_success ? 0 : EINVAL;
+}
+
+int __libcpp_recursive_mutex_lock(__libcpp_recursive_mutex_t *__m)
+{
+  return mtx_lock(__m) == thrd_success ? 0 : EINVAL;
+}
+
+bool __libcpp_recursive_mutex_trylock(__libcpp_recursive_mutex_t *__m)
+{
+  return mtx_trylock(__m) == thrd_success;
+}
+
+int __libcpp_recursive_mutex_unlock(__libcpp_recursive_mutex_t *__m)
+{
+  return mtx_unlock(__m) == thrd_success ? 0 : EINVAL;
+}
+
+int __libcpp_recursive_mutex_destroy(__libcpp_recursive_mutex_t *__m)
+{
+  mtx_destroy(__m);
+  return 0;
+}
+
+int __libcpp_mutex_lock(__libcpp_mutex_t *__m)
+{
+  return mtx_lock(__m) == thrd_success ? 0 : EINVAL;
+}
+
+bool __libcpp_mutex_trylock(__libcpp_mutex_t *__m)
+{
+  return mtx_trylock(__m) == thrd_success;
+}
+
+int __libcpp_mutex_unlock(__libcpp_mutex_t *__m)
+{
+  return mtx_unlock(__m) == thrd_success ? 0 : EINVAL;
+}
+
+int __libcpp_mutex_destroy(__libcpp_mutex_t *__m)
+{
+  mtx_destroy(__m);
+  return 0;
+}
+
+// Condition Variable
+int __libcpp_condvar_signal(__libcpp_condvar_t *__cv)
+{
+  return cnd_signal(__cv) == thrd_success ? 0 : EINVAL;
+}
+
+int __libcpp_condvar_broadcast(__libcpp_condvar_t *__cv)
+{
+  return cnd_broadcast(__cv) == thrd_success ? 0 : EINVAL;
+}
+
+int __libcpp_condvar_wait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m)
+{
+  return cnd_wait(__cv, __m) == thrd_success ? 0 : EINVAL;
+}
+
+int __libcpp_condvar_timedwait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m,
+                               timespec *__ts)
+{
+  int __ec = cnd_timedwait(__cv, __m, __ts);
+  return __ec == thrd_timedout ? ETIMEDOUT : __ec;
+}
+
+int __libcpp_condvar_destroy(__libcpp_condvar_t *__cv)
+{
+  cnd_destroy(__cv);
+  return 0;
+}
+
+// Execute once
+int __libcpp_execute_once(__libcpp_exec_once_flag *flag,
+                          void (*init_routine)(void)) {
+  ::call_once(flag, init_routine);
+  return 0;
+}
+
+// Thread id
+// Returns non-zero if the thread ids are equal, otherwise 0
+bool __libcpp_thread_id_equal(__libcpp_thread_id t1, __libcpp_thread_id t2)
+{
+  return thrd_equal(t1, t2) != 0;
+}
+
+// Returns non-zero if t1 < t2, otherwise 0
+bool __libcpp_thread_id_less(__libcpp_thread_id t1, __libcpp_thread_id t2)
+{
+  return t1 < t2;
+}
+
+// Thread
+bool __libcpp_thread_isnull(const __libcpp_thread_t *__t) {
+  return __libcpp_thread_get_id(__t) == 0;
+}
+
+int __libcpp_thread_create(__libcpp_thread_t *__t, void *(*__func)(void *),
+                           void *__arg)
+{
+  int __ec = thrd_create(__t, reinterpret_cast<thrd_start_t>(__func), __arg);
+  return __ec == thrd_nomem ? ENOMEM : __ec;
+}
+
+__libcpp_thread_id __libcpp_thread_get_current_id()
+{
+  return thrd_current();
+}
+
+__libcpp_thread_id __libcpp_thread_get_id(const __libcpp_thread_t *__t)
+{
+  return *__t;
+}
+
+int __libcpp_thread_join(__libcpp_thread_t *__t)
+{
+  return thrd_join(*__t, nullptr) == thrd_success ? 0 : EINVAL;
+}
+
+int __libcpp_thread_detach(__libcpp_thread_t *__t)
+{
+  return thrd_detach(*__t) == thrd_success ? 0 : EINVAL;
+}
+
+void __libcpp_thread_yield()
+{
+  thrd_yield();
+}
+
+void __libcpp_thread_sleep_for(const chrono::nanoseconds& __ns)
+{
+   __libcpp_timespec_t __ts = __thread_detail::__convert_to_timespec(__ns);
+  thrd_sleep(&__ts, nullptr);
+}
+
+// Thread local storage
+int __libcpp_tls_create(__libcpp_tls_key *__key, void (*__at_exit)(void *))
+{
+  return tss_create(__key, __at_exit) == thrd_success ? 0 : EINVAL;
+}
+
+void *__libcpp_tls_get(__libcpp_tls_key __key)
+{
+  return tss_get(__key);
+}
+
+int __libcpp_tls_set(__libcpp_tls_key __key, void *__p)
+{
+  return tss_set(__key, __p) == thrd_success ? 0 : EINVAL;
+}
+
+#endif
+
+
+#endif // !_LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL || _LIBCPP_BUILDING_THREAD_LIBRARY_EXTERNAL
+
+class _LIBCPP_TYPE_VIS thread;
+class _LIBCPP_TYPE_VIS __thread_id;
+
+namespace this_thread
+{
+
+_LIBCPP_INLINE_VISIBILITY __thread_id get_id() _NOEXCEPT;
+
+}  // this_thread
+
+template<> struct hash<__thread_id>;
+
+class _LIBCPP_TEMPLATE_VIS __thread_id
+{
+    // FIXME: pthread_t is a pointer on Darwin but a long on Linux.
+    // NULL is the no-thread value on Darwin.  Someone needs to check
+    // on other platforms.  We assume 0 works everywhere for now.
+    __libcpp_thread_id __id_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __thread_id() _NOEXCEPT : __id_(0) {}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(__thread_id __x, __thread_id __y) _NOEXCEPT
+        { // don't pass id==0 to underlying routines
+        if (__x.__id_ == 0) return __y.__id_ == 0;
+        if (__y.__id_ == 0) return false;
+        return __libcpp_thread_id_equal(__x.__id_, __y.__id_);
+        }
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(__thread_id __x, __thread_id __y) _NOEXCEPT
+        {return !(__x == __y);}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator< (__thread_id __x, __thread_id __y) _NOEXCEPT
+        { // id==0 is always less than any other thread_id
+        if (__x.__id_ == 0) return __y.__id_ != 0;
+        if (__y.__id_ == 0) return false;
+        return  __libcpp_thread_id_less(__x.__id_, __y.__id_);
+        }
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator<=(__thread_id __x, __thread_id __y) _NOEXCEPT
+        {return !(__y < __x);}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator> (__thread_id __x, __thread_id __y) _NOEXCEPT
+        {return   __y < __x ;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator>=(__thread_id __x, __thread_id __y) _NOEXCEPT
+        {return !(__x < __y);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __reset() { __id_ = 0; }
+
+    template<class _CharT, class _Traits>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id);
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    __thread_id(__libcpp_thread_id __id) : __id_(__id) {}
+
+    friend __thread_id this_thread::get_id() _NOEXCEPT;
+    friend class _LIBCPP_TYPE_VIS thread;
+    friend struct _LIBCPP_TEMPLATE_VIS hash<__thread_id>;
+};
+
+namespace this_thread
+{
+
+inline _LIBCPP_INLINE_VISIBILITY
+__thread_id
+get_id() _NOEXCEPT
+{
+    return __libcpp_thread_get_current_id();
+}
+
+}  // this_thread
+
+#endif // !_LIBCPP_HAS_NO_THREADS
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_THREADING_SUPPORT
diff --git a/contrib/libs/cxxsupp/libcxx/include/__tree b/contrib/libs/cxxsupp/libcxx/include/__tree
new file mode 100644
index 00000000000..f3f2e8d15f5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__tree
@@ -0,0 +1,2748 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___TREE
+#define _LIBCPP___TREE
+
+#include <__config>
+#include <__utility/forward.h>
+#include <algorithm>
+#include <iterator>
+#include <limits>
+#include <memory>
+#include <stdexcept>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if defined(__GNUC__) && !defined(__clang__) // gcc.gnu.org/PR37804
+template <class, class, class, class> class _LIBCPP_TEMPLATE_VIS map;
+template <class, class, class, class> class _LIBCPP_TEMPLATE_VIS multimap;
+template <class, class, class> class _LIBCPP_TEMPLATE_VIS set;
+template <class, class, class> class _LIBCPP_TEMPLATE_VIS multiset;
+#endif
+
+template <class _Tp, class _Compare, class _Allocator> class __tree;
+template <class _Tp, class _NodePtr, class _DiffType>
+    class _LIBCPP_TEMPLATE_VIS __tree_iterator;
+template <class _Tp, class _ConstNodePtr, class _DiffType>
+    class _LIBCPP_TEMPLATE_VIS __tree_const_iterator;
+
+template <class _Pointer> class __tree_end_node;
+template <class _VoidPtr> class __tree_node_base;
+template <class _Tp, class _VoidPtr> class __tree_node;
+
+template <class _Key, class _Value>
+struct __value_type;
+
+template <class _Allocator> class __map_node_destructor;
+template <class _TreeIterator> class _LIBCPP_TEMPLATE_VIS __map_iterator;
+template <class _TreeIterator> class _LIBCPP_TEMPLATE_VIS __map_const_iterator;
+
+/*
+
+_NodePtr algorithms
+
+The algorithms taking _NodePtr are red black tree algorithms.  Those
+algorithms taking a parameter named __root should assume that __root
+points to a proper red black tree (unless otherwise specified).
+
+Each algorithm herein assumes that __root->__parent_ points to a non-null
+structure which has a member __left_ which points back to __root.  No other
+member is read or written to at __root->__parent_.
+
+__root->__parent_ will be referred to below (in comments only) as end_node.
+end_node->__left_ is an externably accessible lvalue for __root, and can be
+changed by node insertion and removal (without explicit reference to end_node).
+
+All nodes (with the exception of end_node), even the node referred to as
+__root, have a non-null __parent_ field.
+
+*/
+
+// Returns:  true if __x is a left child of its parent, else false
+// Precondition:  __x != nullptr.
+template <class _NodePtr>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+__tree_is_left_child(_NodePtr __x) _NOEXCEPT
+{
+    return __x == __x->__parent_->__left_;
+}
+
+// Determines if the subtree rooted at __x is a proper red black subtree.  If
+//    __x is a proper subtree, returns the black height (null counts as 1).  If
+//    __x is an improper subtree, returns 0.
+template <class _NodePtr>
+unsigned
+__tree_sub_invariant(_NodePtr __x)
+{
+    if (__x == nullptr)
+        return 1;
+    // parent consistency checked by caller
+    // check __x->__left_ consistency
+    if (__x->__left_ != nullptr && __x->__left_->__parent_ != __x)
+        return 0;
+    // check __x->__right_ consistency
+    if (__x->__right_ != nullptr && __x->__right_->__parent_ != __x)
+        return 0;
+    // check __x->__left_ != __x->__right_ unless both are nullptr
+    if (__x->__left_ == __x->__right_ && __x->__left_ != nullptr)
+        return 0;
+    // If this is red, neither child can be red
+    if (!__x->__is_black_)
+    {
+        if (__x->__left_ && !__x->__left_->__is_black_)
+            return 0;
+        if (__x->__right_ && !__x->__right_->__is_black_)
+            return 0;
+    }
+    unsigned __h = _VSTD::__tree_sub_invariant(__x->__left_);
+    if (__h == 0)
+        return 0;  // invalid left subtree
+    if (__h != _VSTD::__tree_sub_invariant(__x->__right_))
+        return 0;  // invalid or different height right subtree
+    return __h + __x->__is_black_;  // return black height of this node
+}
+
+// Determines if the red black tree rooted at __root is a proper red black tree.
+//    __root == nullptr is a proper tree.  Returns true is __root is a proper
+//    red black tree, else returns false.
+template <class _NodePtr>
+bool
+__tree_invariant(_NodePtr __root)
+{
+    if (__root == nullptr)
+        return true;
+    // check __x->__parent_ consistency
+    if (__root->__parent_ == nullptr)
+        return false;
+    if (!_VSTD::__tree_is_left_child(__root))
+        return false;
+    // root must be black
+    if (!__root->__is_black_)
+        return false;
+    // do normal node checks
+    return _VSTD::__tree_sub_invariant(__root) != 0;
+}
+
+// Returns:  pointer to the left-most node under __x.
+// Precondition:  __x != nullptr.
+template <class _NodePtr>
+inline _LIBCPP_INLINE_VISIBILITY
+_NodePtr
+__tree_min(_NodePtr __x) _NOEXCEPT
+{
+    while (__x->__left_ != nullptr)
+        __x = __x->__left_;
+    return __x;
+}
+
+// Returns:  pointer to the right-most node under __x.
+// Precondition:  __x != nullptr.
+template <class _NodePtr>
+inline _LIBCPP_INLINE_VISIBILITY
+_NodePtr
+__tree_max(_NodePtr __x) _NOEXCEPT
+{
+    while (__x->__right_ != nullptr)
+        __x = __x->__right_;
+    return __x;
+}
+
+// Returns:  pointer to the next in-order node after __x.
+// Precondition:  __x != nullptr.
+template <class _NodePtr>
+_NodePtr
+__tree_next(_NodePtr __x) _NOEXCEPT
+{
+    if (__x->__right_ != nullptr)
+        return _VSTD::__tree_min(__x->__right_);
+    while (!_VSTD::__tree_is_left_child(__x))
+        __x = __x->__parent_unsafe();
+    return __x->__parent_unsafe();
+}
+
+template <class _EndNodePtr, class _NodePtr>
+inline _LIBCPP_INLINE_VISIBILITY
+_EndNodePtr
+__tree_next_iter(_NodePtr __x) _NOEXCEPT
+{
+    if (__x->__right_ != nullptr)
+        return static_cast<_EndNodePtr>(_VSTD::__tree_min(__x->__right_));
+    while (!_VSTD::__tree_is_left_child(__x))
+        __x = __x->__parent_unsafe();
+    return static_cast<_EndNodePtr>(__x->__parent_);
+}
+
+// Returns:  pointer to the previous in-order node before __x.
+// Precondition:  __x != nullptr.
+// Note: __x may be the end node.
+template <class _NodePtr, class _EndNodePtr>
+inline _LIBCPP_INLINE_VISIBILITY
+_NodePtr
+__tree_prev_iter(_EndNodePtr __x) _NOEXCEPT
+{
+    if (__x->__left_ != nullptr)
+        return _VSTD::__tree_max(__x->__left_);
+    _NodePtr __xx = static_cast<_NodePtr>(__x);
+    while (_VSTD::__tree_is_left_child(__xx))
+        __xx = __xx->__parent_unsafe();
+    return __xx->__parent_unsafe();
+}
+
+// Returns:  pointer to a node which has no children
+// Precondition:  __x != nullptr.
+template <class _NodePtr>
+_NodePtr
+__tree_leaf(_NodePtr __x) _NOEXCEPT
+{
+    while (true)
+    {
+        if (__x->__left_ != nullptr)
+        {
+            __x = __x->__left_;
+            continue;
+        }
+        if (__x->__right_ != nullptr)
+        {
+            __x = __x->__right_;
+            continue;
+        }
+        break;
+    }
+    return __x;
+}
+
+// Effects:  Makes __x->__right_ the subtree root with __x as its left child
+//           while preserving in-order order.
+// Precondition:  __x->__right_ != nullptr
+template <class _NodePtr>
+void
+__tree_left_rotate(_NodePtr __x) _NOEXCEPT
+{
+    _NodePtr __y = __x->__right_;
+    __x->__right_ = __y->__left_;
+    if (__x->__right_ != nullptr)
+        __x->__right_->__set_parent(__x);
+    __y->__parent_ = __x->__parent_;
+    if (_VSTD::__tree_is_left_child(__x))
+        __x->__parent_->__left_ = __y;
+    else
+        __x->__parent_unsafe()->__right_ = __y;
+    __y->__left_ = __x;
+    __x->__set_parent(__y);
+}
+
+// Effects:  Makes __x->__left_ the subtree root with __x as its right child
+//           while preserving in-order order.
+// Precondition:  __x->__left_ != nullptr
+template <class _NodePtr>
+void
+__tree_right_rotate(_NodePtr __x) _NOEXCEPT
+{
+    _NodePtr __y = __x->__left_;
+    __x->__left_ = __y->__right_;
+    if (__x->__left_ != nullptr)
+        __x->__left_->__set_parent(__x);
+    __y->__parent_ = __x->__parent_;
+    if (_VSTD::__tree_is_left_child(__x))
+        __x->__parent_->__left_ = __y;
+    else
+        __x->__parent_unsafe()->__right_ = __y;
+    __y->__right_ = __x;
+    __x->__set_parent(__y);
+}
+
+// Effects:  Rebalances __root after attaching __x to a leaf.
+// Precondition:  __root != nulptr && __x != nullptr.
+//                __x has no children.
+//                __x == __root or == a direct or indirect child of __root.
+//                If __x were to be unlinked from __root (setting __root to
+//                  nullptr if __root == __x), __tree_invariant(__root) == true.
+// Postcondition: __tree_invariant(end_node->__left_) == true.  end_node->__left_
+//                may be different than the value passed in as __root.
+template <class _NodePtr>
+void
+__tree_balance_after_insert(_NodePtr __root, _NodePtr __x) _NOEXCEPT
+{
+    __x->__is_black_ = __x == __root;
+    while (__x != __root && !__x->__parent_unsafe()->__is_black_)
+    {
+        // __x->__parent_ != __root because __x->__parent_->__is_black == false
+        if (_VSTD::__tree_is_left_child(__x->__parent_unsafe()))
+        {
+            _NodePtr __y = __x->__parent_unsafe()->__parent_unsafe()->__right_;
+            if (__y != nullptr && !__y->__is_black_)
+            {
+                __x = __x->__parent_unsafe();
+                __x->__is_black_ = true;
+                __x = __x->__parent_unsafe();
+                __x->__is_black_ = __x == __root;
+                __y->__is_black_ = true;
+            }
+            else
+            {
+                if (!_VSTD::__tree_is_left_child(__x))
+                {
+                    __x = __x->__parent_unsafe();
+                    _VSTD::__tree_left_rotate(__x);
+                }
+                __x = __x->__parent_unsafe();
+                __x->__is_black_ = true;
+                __x = __x->__parent_unsafe();
+                __x->__is_black_ = false;
+                _VSTD::__tree_right_rotate(__x);
+                break;
+            }
+        }
+        else
+        {
+            _NodePtr __y = __x->__parent_unsafe()->__parent_->__left_;
+            if (__y != nullptr && !__y->__is_black_)
+            {
+                __x = __x->__parent_unsafe();
+                __x->__is_black_ = true;
+                __x = __x->__parent_unsafe();
+                __x->__is_black_ = __x == __root;
+                __y->__is_black_ = true;
+            }
+            else
+            {
+                if (_VSTD::__tree_is_left_child(__x))
+                {
+                    __x = __x->__parent_unsafe();
+                    _VSTD::__tree_right_rotate(__x);
+                }
+                __x = __x->__parent_unsafe();
+                __x->__is_black_ = true;
+                __x = __x->__parent_unsafe();
+                __x->__is_black_ = false;
+                _VSTD::__tree_left_rotate(__x);
+                break;
+            }
+        }
+    }
+}
+
+// Precondition:  __root != nullptr && __z != nullptr.
+//                __tree_invariant(__root) == true.
+//                __z == __root or == a direct or indirect child of __root.
+// Effects:  unlinks __z from the tree rooted at __root, rebalancing as needed.
+// Postcondition: __tree_invariant(end_node->__left_) == true && end_node->__left_
+//                nor any of its children refer to __z.  end_node->__left_
+//                may be different than the value passed in as __root.
+template <class _NodePtr>
+void
+__tree_remove(_NodePtr __root, _NodePtr __z) _NOEXCEPT
+{
+    // __z will be removed from the tree.  Client still needs to destruct/deallocate it
+    // __y is either __z, or if __z has two children, __tree_next(__z).
+    // __y will have at most one child.
+    // __y will be the initial hole in the tree (make the hole at a leaf)
+    _NodePtr __y = (__z->__left_ == nullptr || __z->__right_ == nullptr) ?
+                    __z : _VSTD::__tree_next(__z);
+    // __x is __y's possibly null single child
+    _NodePtr __x = __y->__left_ != nullptr ? __y->__left_ : __y->__right_;
+    // __w is __x's possibly null uncle (will become __x's sibling)
+    _NodePtr __w = nullptr;
+    // link __x to __y's parent, and find __w
+    if (__x != nullptr)
+        __x->__parent_ = __y->__parent_;
+    if (_VSTD::__tree_is_left_child(__y))
+    {
+        __y->__parent_->__left_ = __x;
+        if (__y != __root)
+            __w = __y->__parent_unsafe()->__right_;
+        else
+            __root = __x;  // __w == nullptr
+    }
+    else
+    {
+        __y->__parent_unsafe()->__right_ = __x;
+        // __y can't be root if it is a right child
+        __w = __y->__parent_->__left_;
+    }
+    bool __removed_black = __y->__is_black_;
+    // If we didn't remove __z, do so now by splicing in __y for __z,
+    //    but copy __z's color.  This does not impact __x or __w.
+    if (__y != __z)
+    {
+        // __z->__left_ != nulptr but __z->__right_ might == __x == nullptr
+        __y->__parent_ = __z->__parent_;
+        if (_VSTD::__tree_is_left_child(__z))
+            __y->__parent_->__left_ = __y;
+        else
+            __y->__parent_unsafe()->__right_ = __y;
+        __y->__left_ = __z->__left_;
+        __y->__left_->__set_parent(__y);
+        __y->__right_ = __z->__right_;
+        if (__y->__right_ != nullptr)
+            __y->__right_->__set_parent(__y);
+        __y->__is_black_ = __z->__is_black_;
+        if (__root == __z)
+            __root = __y;
+    }
+    // There is no need to rebalance if we removed a red, or if we removed
+    //     the last node.
+    if (__removed_black && __root != nullptr)
+    {
+        // Rebalance:
+        // __x has an implicit black color (transferred from the removed __y)
+        //    associated with it, no matter what its color is.
+        // If __x is __root (in which case it can't be null), it is supposed
+        //    to be black anyway, and if it is doubly black, then the double
+        //    can just be ignored.
+        // If __x is red (in which case it can't be null), then it can absorb
+        //    the implicit black just by setting its color to black.
+        // Since __y was black and only had one child (which __x points to), __x
+        //   is either red with no children, else null, otherwise __y would have
+        //   different black heights under left and right pointers.
+        // if (__x == __root || __x != nullptr && !__x->__is_black_)
+        if (__x != nullptr)
+            __x->__is_black_ = true;
+        else
+        {
+            //  Else __x isn't root, and is "doubly black", even though it may
+            //     be null.  __w can not be null here, else the parent would
+            //     see a black height >= 2 on the __x side and a black height
+            //     of 1 on the __w side (__w must be a non-null black or a red
+            //     with a non-null black child).
+            while (true)
+            {
+                if (!_VSTD::__tree_is_left_child(__w))  // if x is left child
+                {
+                    if (!__w->__is_black_)
+                    {
+                        __w->__is_black_ = true;
+                        __w->__parent_unsafe()->__is_black_ = false;
+                        _VSTD::__tree_left_rotate(__w->__parent_unsafe());
+                        // __x is still valid
+                        // reset __root only if necessary
+                        if (__root == __w->__left_)
+                            __root = __w;
+                        // reset sibling, and it still can't be null
+                        __w = __w->__left_->__right_;
+                    }
+                    // __w->__is_black_ is now true, __w may have null children
+                    if ((__w->__left_  == nullptr || __w->__left_->__is_black_) &&
+                        (__w->__right_ == nullptr || __w->__right_->__is_black_))
+                    {
+                        __w->__is_black_ = false;
+                        __x = __w->__parent_unsafe();
+                        // __x can no longer be null
+                        if (__x == __root || !__x->__is_black_)
+                        {
+                            __x->__is_black_ = true;
+                            break;
+                        }
+                        // reset sibling, and it still can't be null
+                        __w = _VSTD::__tree_is_left_child(__x) ?
+                                    __x->__parent_unsafe()->__right_ :
+                                    __x->__parent_->__left_;
+                        // continue;
+                    }
+                    else  // __w has a red child
+                    {
+                        if (__w->__right_ == nullptr || __w->__right_->__is_black_)
+                        {
+                            // __w left child is non-null and red
+                            __w->__left_->__is_black_ = true;
+                            __w->__is_black_ = false;
+                            _VSTD::__tree_right_rotate(__w);
+                            // __w is known not to be root, so root hasn't changed
+                            // reset sibling, and it still can't be null
+                            __w = __w->__parent_unsafe();
+                        }
+                        // __w has a right red child, left child may be null
+                        __w->__is_black_ = __w->__parent_unsafe()->__is_black_;
+                        __w->__parent_unsafe()->__is_black_ = true;
+                        __w->__right_->__is_black_ = true;
+                        _VSTD::__tree_left_rotate(__w->__parent_unsafe());
+                        break;
+                    }
+                }
+                else
+                {
+                    if (!__w->__is_black_)
+                    {
+                        __w->__is_black_ = true;
+                        __w->__parent_unsafe()->__is_black_ = false;
+                        _VSTD::__tree_right_rotate(__w->__parent_unsafe());
+                        // __x is still valid
+                        // reset __root only if necessary
+                        if (__root == __w->__right_)
+                            __root = __w;
+                        // reset sibling, and it still can't be null
+                        __w = __w->__right_->__left_;
+                    }
+                    // __w->__is_black_ is now true, __w may have null children
+                    if ((__w->__left_  == nullptr || __w->__left_->__is_black_) &&
+                        (__w->__right_ == nullptr || __w->__right_->__is_black_))
+                    {
+                        __w->__is_black_ = false;
+                        __x = __w->__parent_unsafe();
+                        // __x can no longer be null
+                        if (!__x->__is_black_ || __x == __root)
+                        {
+                            __x->__is_black_ = true;
+                            break;
+                        }
+                        // reset sibling, and it still can't be null
+                        __w = _VSTD::__tree_is_left_child(__x) ?
+                                    __x->__parent_unsafe()->__right_ :
+                                    __x->__parent_->__left_;
+                        // continue;
+                    }
+                    else  // __w has a red child
+                    {
+                        if (__w->__left_ == nullptr || __w->__left_->__is_black_)
+                        {
+                            // __w right child is non-null and red
+                            __w->__right_->__is_black_ = true;
+                            __w->__is_black_ = false;
+                            _VSTD::__tree_left_rotate(__w);
+                            // __w is known not to be root, so root hasn't changed
+                            // reset sibling, and it still can't be null
+                            __w = __w->__parent_unsafe();
+                        }
+                        // __w has a left red child, right child may be null
+                        __w->__is_black_ = __w->__parent_unsafe()->__is_black_;
+                        __w->__parent_unsafe()->__is_black_ = true;
+                        __w->__left_->__is_black_ = true;
+                        _VSTD::__tree_right_rotate(__w->__parent_unsafe());
+                        break;
+                    }
+                }
+            }
+        }
+    }
+}
+
+// node traits
+
+
+template <class _Tp>
+struct __is_tree_value_type_imp : false_type {};
+
+template <class _Key, class _Value>
+struct __is_tree_value_type_imp<__value_type<_Key, _Value> > : true_type {};
+
+template <class ..._Args>
+struct __is_tree_value_type : false_type {};
+
+template <class _One>
+struct __is_tree_value_type<_One> : __is_tree_value_type_imp<typename __uncvref<_One>::type> {};
+
+template <class _Tp>
+struct __tree_key_value_types {
+  typedef _Tp key_type;
+  typedef _Tp __node_value_type;
+  typedef _Tp __container_value_type;
+  static const bool __is_map = false;
+
+  _LIBCPP_INLINE_VISIBILITY
+  static key_type const& __get_key(_Tp const& __v) {
+    return __v;
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  static __container_value_type const& __get_value(__node_value_type const& __v) {
+    return __v;
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  static __container_value_type* __get_ptr(__node_value_type& __n) {
+    return _VSTD::addressof(__n);
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  static __container_value_type&& __move(__node_value_type& __v) {
+    return _VSTD::move(__v);
+  }
+};
+
+template <class _Key, class _Tp>
+struct __tree_key_value_types<__value_type<_Key, _Tp> > {
+  typedef _Key                                         key_type;
+  typedef _Tp                                          mapped_type;
+  typedef __value_type<_Key, _Tp>                      __node_value_type;
+  typedef pair<const _Key, _Tp>                        __container_value_type;
+  typedef __container_value_type                       __map_value_type;
+  static const bool __is_map = true;
+
+  _LIBCPP_INLINE_VISIBILITY
+  static key_type const&
+  __get_key(__node_value_type const& __t) {
+    return __t.__get_value().first;
+  }
+
+  template <class _Up>
+  _LIBCPP_INLINE_VISIBILITY
+  static typename enable_if<__is_same_uncvref<_Up, __container_value_type>::value,
+      key_type const&>::type
+  __get_key(_Up& __t) {
+    return __t.first;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  static __container_value_type const&
+  __get_value(__node_value_type const& __t) {
+    return __t.__get_value();
+  }
+
+  template <class _Up>
+  _LIBCPP_INLINE_VISIBILITY
+  static typename enable_if<__is_same_uncvref<_Up, __container_value_type>::value,
+      __container_value_type const&>::type
+  __get_value(_Up& __t) {
+    return __t;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  static __container_value_type* __get_ptr(__node_value_type& __n) {
+    return _VSTD::addressof(__n.__get_value());
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  static pair<key_type&&, mapped_type&&> __move(__node_value_type& __v) {
+    return __v.__move();
+  }
+};
+
+template <class _VoidPtr>
+struct __tree_node_base_types {
+  typedef _VoidPtr                                               __void_pointer;
+
+  typedef __tree_node_base<__void_pointer>                      __node_base_type;
+  typedef typename __rebind_pointer<_VoidPtr, __node_base_type>::type
+                                                             __node_base_pointer;
+
+  typedef __tree_end_node<__node_base_pointer>                  __end_node_type;
+  typedef typename __rebind_pointer<_VoidPtr, __end_node_type>::type
+                                                             __end_node_pointer;
+#if defined(_LIBCPP_ABI_TREE_REMOVE_NODE_POINTER_UB)
+  typedef __end_node_pointer __parent_pointer;
+#else
+  typedef typename conditional<
+      is_pointer<__end_node_pointer>::value,
+        __end_node_pointer,
+        __node_base_pointer>::type __parent_pointer;
+#endif
+
+private:
+  static_assert((is_same<typename pointer_traits<_VoidPtr>::element_type, void>::value),
+                  "_VoidPtr does not point to unqualified void type");
+};
+
+template <class _Tp, class _AllocPtr, class _KVTypes = __tree_key_value_types<_Tp>,
+         bool = _KVTypes::__is_map>
+struct __tree_map_pointer_types {};
+
+template <class _Tp, class _AllocPtr, class _KVTypes>
+struct __tree_map_pointer_types<_Tp, _AllocPtr, _KVTypes, true> {
+  typedef typename _KVTypes::__map_value_type   _Mv;
+  typedef typename __rebind_pointer<_AllocPtr, _Mv>::type
+                                                       __map_value_type_pointer;
+  typedef typename __rebind_pointer<_AllocPtr, const _Mv>::type
+                                                 __const_map_value_type_pointer;
+};
+
+template <class _NodePtr, class _NodeT = typename pointer_traits<_NodePtr>::element_type>
+struct __tree_node_types;
+
+template <class _NodePtr, class _Tp, class _VoidPtr>
+struct __tree_node_types<_NodePtr, __tree_node<_Tp, _VoidPtr> >
+    : public __tree_node_base_types<_VoidPtr>,
+             __tree_key_value_types<_Tp>,
+             __tree_map_pointer_types<_Tp, _VoidPtr>
+{
+  typedef __tree_node_base_types<_VoidPtr> __base;
+  typedef __tree_key_value_types<_Tp>      __key_base;
+  typedef __tree_map_pointer_types<_Tp, _VoidPtr> __map_pointer_base;
+public:
+
+  typedef typename pointer_traits<_NodePtr>::element_type       __node_type;
+  typedef _NodePtr                                              __node_pointer;
+
+  typedef _Tp                                                 __node_value_type;
+  typedef typename __rebind_pointer<_VoidPtr, __node_value_type>::type
+                                                      __node_value_type_pointer;
+  typedef typename __rebind_pointer<_VoidPtr, const __node_value_type>::type
+                                                __const_node_value_type_pointer;
+#if defined(_LIBCPP_ABI_TREE_REMOVE_NODE_POINTER_UB)
+  typedef typename __base::__end_node_pointer __iter_pointer;
+#else
+  typedef typename conditional<
+      is_pointer<__node_pointer>::value,
+        typename __base::__end_node_pointer,
+        __node_pointer>::type __iter_pointer;
+#endif
+private:
+    static_assert(!is_const<__node_type>::value,
+                "_NodePtr should never be a pointer to const");
+    static_assert((is_same<typename __rebind_pointer<_VoidPtr, __node_type>::type,
+                          _NodePtr>::value), "_VoidPtr does not rebind to _NodePtr.");
+};
+
+template <class _ValueTp, class _VoidPtr>
+struct __make_tree_node_types {
+  typedef typename __rebind_pointer<_VoidPtr, __tree_node<_ValueTp, _VoidPtr> >::type
+                                                                        _NodePtr;
+  typedef __tree_node_types<_NodePtr> type;
+};
+
+// node
+
+template <class _Pointer>
+class __tree_end_node
+{
+public:
+    typedef _Pointer pointer;
+    pointer __left_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __tree_end_node() _NOEXCEPT : __left_() {}
+};
+
+template <class _VoidPtr>
+class _LIBCPP_STANDALONE_DEBUG __tree_node_base
+    : public __tree_node_base_types<_VoidPtr>::__end_node_type
+{
+    typedef __tree_node_base_types<_VoidPtr> _NodeBaseTypes;
+
+public:
+    typedef typename _NodeBaseTypes::__node_base_pointer pointer;
+    typedef typename _NodeBaseTypes::__parent_pointer __parent_pointer;
+
+    pointer          __right_;
+    __parent_pointer __parent_;
+    bool __is_black_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    pointer __parent_unsafe() const { return static_cast<pointer>(__parent_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __set_parent(pointer __p) {
+        __parent_ = static_cast<__parent_pointer>(__p);
+    }
+
+private:
+  ~__tree_node_base() = delete;
+  __tree_node_base(__tree_node_base const&) = delete;
+  __tree_node_base& operator=(__tree_node_base const&) = delete;
+};
+
+template <class _Tp, class _VoidPtr>
+class _LIBCPP_STANDALONE_DEBUG __tree_node
+    : public __tree_node_base<_VoidPtr>
+{
+public:
+    typedef _Tp __node_value_type;
+
+    __node_value_type __value_;
+
+private:
+  ~__tree_node() = delete;
+  __tree_node(__tree_node const&) = delete;
+  __tree_node& operator=(__tree_node const&) = delete;
+};
+
+
+template <class _Allocator>
+class __tree_node_destructor
+{
+    typedef _Allocator                                      allocator_type;
+    typedef allocator_traits<allocator_type>                __alloc_traits;
+
+public:
+    typedef typename __alloc_traits::pointer                pointer;
+private:
+    typedef __tree_node_types<pointer> _NodeTypes;
+    allocator_type& __na_;
+
+
+public:
+    bool __value_constructed;
+
+
+    __tree_node_destructor(const __tree_node_destructor &) = default;
+    __tree_node_destructor& operator=(const __tree_node_destructor&) = delete;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __tree_node_destructor(allocator_type& __na, bool __val = false) _NOEXCEPT
+        : __na_(__na),
+          __value_constructed(__val)
+        {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator()(pointer __p) _NOEXCEPT
+    {
+        if (__value_constructed)
+            __alloc_traits::destroy(__na_, _NodeTypes::__get_ptr(__p->__value_));
+        if (__p)
+            __alloc_traits::deallocate(__na_, __p, 1);
+    }
+
+    template <class> friend class __map_node_destructor;
+};
+
+#if _LIBCPP_STD_VER > 14
+template <class _NodeType, class _Alloc>
+struct __generic_container_node_destructor;
+template <class _Tp, class _VoidPtr, class _Alloc>
+struct __generic_container_node_destructor<__tree_node<_Tp, _VoidPtr>, _Alloc>
+    : __tree_node_destructor<_Alloc>
+{
+    using __tree_node_destructor<_Alloc>::__tree_node_destructor;
+};
+#endif
+
+template <class _Tp, class _NodePtr, class _DiffType>
+class _LIBCPP_TEMPLATE_VIS __tree_iterator
+{
+    typedef __tree_node_types<_NodePtr>                     _NodeTypes;
+    typedef _NodePtr                                        __node_pointer;
+    typedef typename _NodeTypes::__node_base_pointer        __node_base_pointer;
+    typedef typename _NodeTypes::__end_node_pointer         __end_node_pointer;
+    typedef typename _NodeTypes::__iter_pointer             __iter_pointer;
+    typedef pointer_traits<__node_pointer> __pointer_traits;
+
+    __iter_pointer __ptr_;
+
+public:
+    typedef bidirectional_iterator_tag                     iterator_category;
+    typedef _Tp                                            value_type;
+    typedef _DiffType                                      difference_type;
+    typedef value_type&                                    reference;
+    typedef typename _NodeTypes::__node_value_type_pointer pointer;
+
+    _LIBCPP_INLINE_VISIBILITY __tree_iterator() _NOEXCEPT
+#if _LIBCPP_STD_VER > 11
+    : __ptr_(nullptr)
+#endif
+    {}
+
+    _LIBCPP_INLINE_VISIBILITY reference operator*() const
+        {return __get_np()->__value_;}
+    _LIBCPP_INLINE_VISIBILITY pointer operator->() const
+        {return pointer_traits<pointer>::pointer_to(__get_np()->__value_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __tree_iterator& operator++() {
+      __ptr_ = static_cast<__iter_pointer>(
+          _VSTD::__tree_next_iter<__end_node_pointer>(static_cast<__node_base_pointer>(__ptr_)));
+      return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __tree_iterator operator++(int)
+        {__tree_iterator __t(*this); ++(*this); return __t;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __tree_iterator& operator--() {
+      __ptr_ = static_cast<__iter_pointer>(_VSTD::__tree_prev_iter<__node_base_pointer>(
+          static_cast<__end_node_pointer>(__ptr_)));
+      return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __tree_iterator operator--(int)
+        {__tree_iterator __t(*this); --(*this); return __t;}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const __tree_iterator& __x, const __tree_iterator& __y)
+        {return __x.__ptr_ == __y.__ptr_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const __tree_iterator& __x, const __tree_iterator& __y)
+        {return !(__x == __y);}
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __tree_iterator(__node_pointer __p) _NOEXCEPT : __ptr_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __tree_iterator(__end_node_pointer __p) _NOEXCEPT : __ptr_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    __node_pointer __get_np() const { return static_cast<__node_pointer>(__ptr_); }
+    template <class, class, class> friend class __tree;
+    template <class, class, class> friend class _LIBCPP_TEMPLATE_VIS __tree_const_iterator;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __map_iterator;
+    template <class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS map;
+    template <class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS multimap;
+    template <class, class, class> friend class _LIBCPP_TEMPLATE_VIS set;
+    template <class, class, class> friend class _LIBCPP_TEMPLATE_VIS multiset;
+};
+
+template <class _Tp, class _NodePtr, class _DiffType>
+class _LIBCPP_TEMPLATE_VIS __tree_const_iterator
+{
+    typedef __tree_node_types<_NodePtr>                     _NodeTypes;
+    typedef typename _NodeTypes::__node_pointer             __node_pointer;
+    typedef typename _NodeTypes::__node_base_pointer        __node_base_pointer;
+    typedef typename _NodeTypes::__end_node_pointer         __end_node_pointer;
+    typedef typename _NodeTypes::__iter_pointer             __iter_pointer;
+    typedef pointer_traits<__node_pointer> __pointer_traits;
+
+    __iter_pointer __ptr_;
+
+public:
+    typedef bidirectional_iterator_tag                           iterator_category;
+    typedef _Tp                                                  value_type;
+    typedef _DiffType                                            difference_type;
+    typedef const value_type&                                    reference;
+    typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
+
+    _LIBCPP_INLINE_VISIBILITY __tree_const_iterator() _NOEXCEPT
+#if _LIBCPP_STD_VER > 11
+    : __ptr_(nullptr)
+#endif
+    {}
+
+private:
+    typedef __tree_iterator<value_type, __node_pointer, difference_type>
+                                                           __non_const_iterator;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __tree_const_iterator(__non_const_iterator __p) _NOEXCEPT
+        : __ptr_(__p.__ptr_) {}
+
+    _LIBCPP_INLINE_VISIBILITY reference operator*() const
+        {return __get_np()->__value_;}
+    _LIBCPP_INLINE_VISIBILITY pointer operator->() const
+        {return pointer_traits<pointer>::pointer_to(__get_np()->__value_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __tree_const_iterator& operator++() {
+      __ptr_ = static_cast<__iter_pointer>(
+          _VSTD::__tree_next_iter<__end_node_pointer>(static_cast<__node_base_pointer>(__ptr_)));
+      return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __tree_const_iterator operator++(int)
+        {__tree_const_iterator __t(*this); ++(*this); return __t;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __tree_const_iterator& operator--() {
+      __ptr_ = static_cast<__iter_pointer>(_VSTD::__tree_prev_iter<__node_base_pointer>(
+          static_cast<__end_node_pointer>(__ptr_)));
+      return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __tree_const_iterator operator--(int)
+        {__tree_const_iterator __t(*this); --(*this); return __t;}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const __tree_const_iterator& __x, const __tree_const_iterator& __y)
+        {return __x.__ptr_ == __y.__ptr_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const __tree_const_iterator& __x, const __tree_const_iterator& __y)
+        {return !(__x == __y);}
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __tree_const_iterator(__node_pointer __p) _NOEXCEPT
+        : __ptr_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __tree_const_iterator(__end_node_pointer __p) _NOEXCEPT
+        : __ptr_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    __node_pointer __get_np() const { return static_cast<__node_pointer>(__ptr_); }
+
+    template <class, class, class> friend class __tree;
+    template <class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS map;
+    template <class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS multimap;
+    template <class, class, class> friend class _LIBCPP_TEMPLATE_VIS set;
+    template <class, class, class> friend class _LIBCPP_TEMPLATE_VIS multiset;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __map_const_iterator;
+
+};
+
+template<class _Tp, class _Compare>
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_DIAGNOSE_WARNING(!__invokable<_Compare const&, _Tp const&, _Tp const&>::value,
+        "the specified comparator type does not provide a viable const call operator")
+#endif
+int __diagnose_non_const_comparator();
+
+template <class _Tp, class _Compare, class _Allocator>
+class __tree
+{
+public:
+    typedef _Tp                                      value_type;
+    typedef _Compare                                 value_compare;
+    typedef _Allocator                               allocator_type;
+
+private:
+    typedef allocator_traits<allocator_type>         __alloc_traits;
+    typedef typename __make_tree_node_types<value_type,
+        typename __alloc_traits::void_pointer>::type
+                                                    _NodeTypes;
+    typedef typename _NodeTypes::key_type           key_type;
+public:
+    typedef typename _NodeTypes::__node_value_type      __node_value_type;
+    typedef typename _NodeTypes::__container_value_type __container_value_type;
+
+    typedef typename __alloc_traits::pointer         pointer;
+    typedef typename __alloc_traits::const_pointer   const_pointer;
+    typedef typename __alloc_traits::size_type       size_type;
+    typedef typename __alloc_traits::difference_type difference_type;
+
+public:
+    typedef typename _NodeTypes::__void_pointer        __void_pointer;
+
+    typedef typename _NodeTypes::__node_type           __node;
+    typedef typename _NodeTypes::__node_pointer        __node_pointer;
+
+    typedef typename _NodeTypes::__node_base_type      __node_base;
+    typedef typename _NodeTypes::__node_base_pointer   __node_base_pointer;
+
+    typedef typename _NodeTypes::__end_node_type       __end_node_t;
+    typedef typename _NodeTypes::__end_node_pointer    __end_node_ptr;
+
+    typedef typename _NodeTypes::__parent_pointer      __parent_pointer;
+    typedef typename _NodeTypes::__iter_pointer        __iter_pointer;
+
+    typedef typename __rebind_alloc_helper<__alloc_traits, __node>::type __node_allocator;
+    typedef allocator_traits<__node_allocator>         __node_traits;
+
+private:
+    // check for sane allocator pointer rebinding semantics. Rebinding the
+    // allocator for a new pointer type should be exactly the same as rebinding
+    // the pointer using 'pointer_traits'.
+    static_assert((is_same<__node_pointer, typename __node_traits::pointer>::value),
+                  "Allocator does not rebind pointers in a sane manner.");
+    typedef typename __rebind_alloc_helper<__node_traits, __node_base>::type
+        __node_base_allocator;
+    typedef allocator_traits<__node_base_allocator> __node_base_traits;
+    static_assert((is_same<__node_base_pointer, typename __node_base_traits::pointer>::value),
+                 "Allocator does not rebind pointers in a sane manner.");
+
+private:
+    __iter_pointer                                     __begin_node_;
+    __compressed_pair<__end_node_t, __node_allocator>  __pair1_;
+    __compressed_pair<size_type, value_compare>        __pair3_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __iter_pointer __end_node() _NOEXCEPT
+    {
+        return static_cast<__iter_pointer>(
+                pointer_traits<__end_node_ptr>::pointer_to(__pair1_.first())
+        );
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __iter_pointer __end_node() const _NOEXCEPT
+    {
+        return static_cast<__iter_pointer>(
+            pointer_traits<__end_node_ptr>::pointer_to(
+                const_cast<__end_node_t&>(__pair1_.first())
+            )
+        );
+    }
+    _LIBCPP_INLINE_VISIBILITY
+          __node_allocator& __node_alloc() _NOEXCEPT {return __pair1_.second();}
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    const __node_allocator& __node_alloc() const _NOEXCEPT
+        {return __pair1_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+          __iter_pointer& __begin_node() _NOEXCEPT {return __begin_node_;}
+    _LIBCPP_INLINE_VISIBILITY
+    const __iter_pointer& __begin_node() const _NOEXCEPT {return __begin_node_;}
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type __alloc() const _NOEXCEPT
+        {return allocator_type(__node_alloc());}
+private:
+    _LIBCPP_INLINE_VISIBILITY
+          size_type& size() _NOEXCEPT {return __pair3_.first();}
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    const size_type& size() const _NOEXCEPT {return __pair3_.first();}
+    _LIBCPP_INLINE_VISIBILITY
+          value_compare& value_comp() _NOEXCEPT {return __pair3_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    const value_compare& value_comp() const _NOEXCEPT
+        {return __pair3_.second();}
+public:
+
+    _LIBCPP_INLINE_VISIBILITY
+    __node_pointer __root() const _NOEXCEPT
+        {return static_cast<__node_pointer>(__end_node()->__left_);}
+
+    __node_base_pointer* __root_ptr() const _NOEXCEPT {
+        return _VSTD::addressof(__end_node()->__left_);
+    }
+
+    typedef __tree_iterator<value_type, __node_pointer, difference_type>             iterator;
+    typedef __tree_const_iterator<value_type, __node_pointer, difference_type> const_iterator;
+
+    explicit __tree(const value_compare& __comp)
+        _NOEXCEPT_(
+            is_nothrow_default_constructible<__node_allocator>::value &&
+            is_nothrow_copy_constructible<value_compare>::value);
+    explicit __tree(const allocator_type& __a);
+    __tree(const value_compare& __comp, const allocator_type& __a);
+    __tree(const __tree& __t);
+    __tree& operator=(const __tree& __t);
+    template <class _ForwardIterator>
+        void __assign_unique(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _InputIterator>
+        void __assign_multi(_InputIterator __first, _InputIterator __last);
+    __tree(__tree&& __t)
+        _NOEXCEPT_(
+            is_nothrow_move_constructible<__node_allocator>::value &&
+            is_nothrow_move_constructible<value_compare>::value);
+    __tree(__tree&& __t, const allocator_type& __a);
+    __tree& operator=(__tree&& __t)
+        _NOEXCEPT_(
+            __node_traits::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<value_compare>::value &&
+            is_nothrow_move_assignable<__node_allocator>::value);
+    ~__tree();
+
+    _LIBCPP_INLINE_VISIBILITY
+          iterator begin()  _NOEXCEPT {return       iterator(__begin_node());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const _NOEXCEPT {return const_iterator(__begin_node());}
+    _LIBCPP_INLINE_VISIBILITY
+          iterator end() _NOEXCEPT {return       iterator(__end_node());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end() const _NOEXCEPT {return const_iterator(__end_node());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT
+        {return _VSTD::min<size_type>(
+                __node_traits::max_size(__node_alloc()),
+                numeric_limits<difference_type >::max());}
+
+    void clear() _NOEXCEPT;
+
+    void swap(__tree& __t)
+#if _LIBCPP_STD_VER <= 11
+        _NOEXCEPT_(
+            __is_nothrow_swappable<value_compare>::value
+            && (!__node_traits::propagate_on_container_swap::value ||
+                 __is_nothrow_swappable<__node_allocator>::value)
+            );
+#else
+        _NOEXCEPT_(__is_nothrow_swappable<value_compare>::value);
+#endif
+
+    template <class _Key, class ..._Args>
+    pair<iterator, bool>
+    __emplace_unique_key_args(_Key const&, _Args&&... __args);
+    template <class _Key, class ..._Args>
+    pair<iterator, bool>
+    __emplace_hint_unique_key_args(const_iterator, _Key const&, _Args&&...);
+
+    template <class... _Args>
+    pair<iterator, bool> __emplace_unique_impl(_Args&&... __args);
+
+    template <class... _Args>
+    iterator __emplace_hint_unique_impl(const_iterator __p, _Args&&... __args);
+
+    template <class... _Args>
+    iterator __emplace_multi(_Args&&... __args);
+
+    template <class... _Args>
+    iterator __emplace_hint_multi(const_iterator __p, _Args&&... __args);
+
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> __emplace_unique(_Pp&& __x) {
+        return __emplace_unique_extract_key(_VSTD::forward<_Pp>(__x),
+                                            __can_extract_key<_Pp, key_type>());
+    }
+
+    template <class _First, class _Second>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<
+        __can_extract_map_key<_First, key_type, __container_value_type>::value,
+        pair<iterator, bool>
+    >::type __emplace_unique(_First&& __f, _Second&& __s) {
+        return __emplace_unique_key_args(__f, _VSTD::forward<_First>(__f),
+                                              _VSTD::forward<_Second>(__s));
+    }
+
+    template <class... _Args>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> __emplace_unique(_Args&&... __args) {
+        return __emplace_unique_impl(_VSTD::forward<_Args>(__args)...);
+    }
+
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool>
+    __emplace_unique_extract_key(_Pp&& __x, __extract_key_fail_tag) {
+      return __emplace_unique_impl(_VSTD::forward<_Pp>(__x));
+    }
+
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool>
+    __emplace_unique_extract_key(_Pp&& __x, __extract_key_self_tag) {
+      return __emplace_unique_key_args(__x, _VSTD::forward<_Pp>(__x));
+    }
+
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool>
+    __emplace_unique_extract_key(_Pp&& __x, __extract_key_first_tag) {
+      return __emplace_unique_key_args(__x.first, _VSTD::forward<_Pp>(__x));
+    }
+
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __emplace_hint_unique(const_iterator __p, _Pp&& __x) {
+        return __emplace_hint_unique_extract_key(__p, _VSTD::forward<_Pp>(__x),
+                                            __can_extract_key<_Pp, key_type>());
+    }
+
+    template <class _First, class _Second>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<
+        __can_extract_map_key<_First, key_type, __container_value_type>::value,
+        iterator
+    >::type __emplace_hint_unique(const_iterator __p, _First&& __f, _Second&& __s) {
+        return __emplace_hint_unique_key_args(__p, __f,
+                                              _VSTD::forward<_First>(__f),
+                                              _VSTD::forward<_Second>(__s)).first;
+    }
+
+    template <class... _Args>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __emplace_hint_unique(const_iterator __p, _Args&&... __args) {
+        return __emplace_hint_unique_impl(__p, _VSTD::forward<_Args>(__args)...);
+    }
+
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator
+    __emplace_hint_unique_extract_key(const_iterator __p, _Pp&& __x, __extract_key_fail_tag) {
+      return __emplace_hint_unique_impl(__p, _VSTD::forward<_Pp>(__x));
+    }
+
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator
+    __emplace_hint_unique_extract_key(const_iterator __p, _Pp&& __x, __extract_key_self_tag) {
+      return __emplace_hint_unique_key_args(__p, __x, _VSTD::forward<_Pp>(__x)).first;
+    }
+
+    template <class _Pp>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator
+    __emplace_hint_unique_extract_key(const_iterator __p, _Pp&& __x, __extract_key_first_tag) {
+      return __emplace_hint_unique_key_args(__p, __x.first, _VSTD::forward<_Pp>(__x)).first;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> __insert_unique(const __container_value_type& __v) {
+        return __emplace_unique_key_args(_NodeTypes::__get_key(__v), __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __insert_unique(const_iterator __p, const __container_value_type& __v) {
+        return __emplace_hint_unique_key_args(__p, _NodeTypes::__get_key(__v), __v).first;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> __insert_unique(__container_value_type&& __v) {
+        return __emplace_unique_key_args(_NodeTypes::__get_key(__v), _VSTD::move(__v));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __insert_unique(const_iterator __p, __container_value_type&& __v) {
+        return __emplace_hint_unique_key_args(__p, _NodeTypes::__get_key(__v), _VSTD::move(__v)).first;
+    }
+
+    template <class _Vp, class = typename enable_if<
+            !is_same<typename __unconstref<_Vp>::type,
+                     __container_value_type
+            >::value
+        >::type>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> __insert_unique(_Vp&& __v) {
+        return __emplace_unique(_VSTD::forward<_Vp>(__v));
+    }
+
+    template <class _Vp, class = typename enable_if<
+            !is_same<typename __unconstref<_Vp>::type,
+                     __container_value_type
+            >::value
+        >::type>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __insert_unique(const_iterator __p, _Vp&& __v) {
+        return __emplace_hint_unique(__p, _VSTD::forward<_Vp>(__v));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __insert_multi(__container_value_type&& __v) {
+        return __emplace_multi(_VSTD::move(__v));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __insert_multi(const_iterator __p, __container_value_type&& __v) {
+        return __emplace_hint_multi(__p, _VSTD::move(__v));
+    }
+
+    template <class _Vp>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __insert_multi(_Vp&& __v) {
+        return __emplace_multi(_VSTD::forward<_Vp>(__v));
+    }
+
+    template <class _Vp>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __insert_multi(const_iterator __p, _Vp&& __v) {
+        return __emplace_hint_multi(__p, _VSTD::forward<_Vp>(__v));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> __node_assign_unique(const __container_value_type& __v, __node_pointer __dest);
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __node_insert_multi(__node_pointer __nd);
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __node_insert_multi(const_iterator __p, __node_pointer __nd);
+
+
+    _LIBCPP_INLINE_VISIBILITY iterator
+    __remove_node_pointer(__node_pointer) _NOEXCEPT;
+
+#if _LIBCPP_STD_VER > 14
+    template <class _NodeHandle, class _InsertReturnType>
+    _LIBCPP_INLINE_VISIBILITY
+    _InsertReturnType __node_handle_insert_unique(_NodeHandle&&);
+    template <class _NodeHandle>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __node_handle_insert_unique(const_iterator, _NodeHandle&&);
+    template <class _Tree>
+    _LIBCPP_INLINE_VISIBILITY
+    void __node_handle_merge_unique(_Tree& __source);
+
+    template <class _NodeHandle>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __node_handle_insert_multi(_NodeHandle&&);
+    template <class _NodeHandle>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __node_handle_insert_multi(const_iterator, _NodeHandle&&);
+    template <class _Tree>
+    _LIBCPP_INLINE_VISIBILITY
+    void __node_handle_merge_multi(_Tree& __source);
+
+
+    template <class _NodeHandle>
+    _LIBCPP_INLINE_VISIBILITY
+    _NodeHandle __node_handle_extract(key_type const&);
+    template <class _NodeHandle>
+    _LIBCPP_INLINE_VISIBILITY
+    _NodeHandle __node_handle_extract(const_iterator);
+#endif
+
+    iterator erase(const_iterator __p);
+    iterator erase(const_iterator __f, const_iterator __l);
+    template <class _Key>
+        size_type __erase_unique(const _Key& __k);
+    template <class _Key>
+        size_type __erase_multi(const _Key& __k);
+
+    void __insert_node_at(__parent_pointer     __parent,
+                          __node_base_pointer& __child,
+                          __node_base_pointer __new_node) _NOEXCEPT;
+
+    template <class _Key>
+        iterator find(const _Key& __v);
+    template <class _Key>
+        const_iterator find(const _Key& __v) const;
+
+    template <class _Key>
+        size_type __count_unique(const _Key& __k) const;
+    template <class _Key>
+        size_type __count_multi(const _Key& __k) const;
+
+    template <class _Key>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator lower_bound(const _Key& __v)
+            {return __lower_bound(__v, __root(), __end_node());}
+    template <class _Key>
+        iterator __lower_bound(const _Key& __v,
+                               __node_pointer __root,
+                               __iter_pointer __result);
+    template <class _Key>
+        _LIBCPP_INLINE_VISIBILITY
+        const_iterator lower_bound(const _Key& __v) const
+            {return __lower_bound(__v, __root(), __end_node());}
+    template <class _Key>
+        const_iterator __lower_bound(const _Key& __v,
+                                     __node_pointer __root,
+                                     __iter_pointer __result) const;
+    template <class _Key>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator upper_bound(const _Key& __v)
+            {return __upper_bound(__v, __root(), __end_node());}
+    template <class _Key>
+        iterator __upper_bound(const _Key& __v,
+                               __node_pointer __root,
+                               __iter_pointer __result);
+    template <class _Key>
+        _LIBCPP_INLINE_VISIBILITY
+        const_iterator upper_bound(const _Key& __v) const
+            {return __upper_bound(__v, __root(), __end_node());}
+    template <class _Key>
+        const_iterator __upper_bound(const _Key& __v,
+                                     __node_pointer __root,
+                                     __iter_pointer __result) const;
+    template <class _Key>
+        pair<iterator, iterator>
+        __equal_range_unique(const _Key& __k);
+    template <class _Key>
+        pair<const_iterator, const_iterator>
+        __equal_range_unique(const _Key& __k) const;
+
+    template <class _Key>
+        pair<iterator, iterator>
+        __equal_range_multi(const _Key& __k);
+    template <class _Key>
+        pair<const_iterator, const_iterator>
+        __equal_range_multi(const _Key& __k) const;
+
+    typedef __tree_node_destructor<__node_allocator> _Dp;
+    typedef unique_ptr<__node, _Dp> __node_holder;
+
+    __node_holder remove(const_iterator __p) _NOEXCEPT;
+private:
+    __node_base_pointer&
+        __find_leaf_low(__parent_pointer& __parent, const key_type& __v);
+    __node_base_pointer&
+        __find_leaf_high(__parent_pointer& __parent, const key_type& __v);
+    __node_base_pointer&
+        __find_leaf(const_iterator __hint,
+                    __parent_pointer& __parent, const key_type& __v);
+    // FIXME: Make this function const qualified. Unfortunately doing so
+    // breaks existing code which uses non-const callable comparators.
+    template <class _Key>
+    __node_base_pointer&
+        __find_equal(__parent_pointer& __parent, const _Key& __v);
+    template <class _Key>
+    _LIBCPP_INLINE_VISIBILITY __node_base_pointer&
+    __find_equal(__parent_pointer& __parent, const _Key& __v) const {
+      return const_cast<__tree*>(this)->__find_equal(__parent, __v);
+    }
+    template <class _Key>
+    __node_base_pointer&
+        __find_equal(const_iterator __hint, __parent_pointer& __parent,
+                     __node_base_pointer& __dummy,
+                     const _Key& __v);
+
+    template <class ..._Args>
+    __node_holder __construct_node(_Args&& ...__args);
+
+    void destroy(__node_pointer __nd) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __tree& __t)
+        {__copy_assign_alloc(__t, integral_constant<bool,
+             __node_traits::propagate_on_container_copy_assignment::value>());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __tree& __t, true_type)
+        {
+        if (__node_alloc() != __t.__node_alloc())
+            clear();
+        __node_alloc() = __t.__node_alloc();
+        }
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __tree&, false_type) {}
+
+    void __move_assign(__tree& __t, false_type);
+    void __move_assign(__tree& __t, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<value_compare>::value &&
+                   is_nothrow_move_assignable<__node_allocator>::value);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__tree& __t)
+        _NOEXCEPT_(
+            !__node_traits::propagate_on_container_move_assignment::value ||
+            is_nothrow_move_assignable<__node_allocator>::value)
+        {__move_assign_alloc(__t, integral_constant<bool,
+             __node_traits::propagate_on_container_move_assignment::value>());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__tree& __t, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value)
+        {__node_alloc() = _VSTD::move(__t.__node_alloc());}
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__tree&, false_type) _NOEXCEPT {}
+
+    struct _DetachedTreeCache {
+      _LIBCPP_INLINE_VISIBILITY
+      explicit _DetachedTreeCache(__tree *__t) _NOEXCEPT : __t_(__t),
+        __cache_root_(__detach_from_tree(__t)) {
+          __advance();
+        }
+
+      _LIBCPP_INLINE_VISIBILITY
+      __node_pointer __get() const _NOEXCEPT {
+        return __cache_elem_;
+      }
+
+      _LIBCPP_INLINE_VISIBILITY
+      void __advance() _NOEXCEPT {
+        __cache_elem_ = __cache_root_;
+        if (__cache_root_) {
+          __cache_root_ = __detach_next(__cache_root_);
+        }
+      }
+
+      _LIBCPP_INLINE_VISIBILITY
+      ~_DetachedTreeCache() {
+        __t_->destroy(__cache_elem_);
+        if (__cache_root_) {
+          while (__cache_root_->__parent_ != nullptr)
+            __cache_root_ = static_cast<__node_pointer>(__cache_root_->__parent_);
+          __t_->destroy(__cache_root_);
+        }
+      }
+
+       _DetachedTreeCache(_DetachedTreeCache const&) = delete;
+       _DetachedTreeCache& operator=(_DetachedTreeCache const&) = delete;
+
+    private:
+      _LIBCPP_INLINE_VISIBILITY
+      static __node_pointer __detach_from_tree(__tree *__t) _NOEXCEPT;
+      _LIBCPP_INLINE_VISIBILITY
+      static __node_pointer __detach_next(__node_pointer) _NOEXCEPT;
+
+      __tree *__t_;
+      __node_pointer __cache_root_;
+      __node_pointer __cache_elem_;
+    };
+
+
+    template <class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS map;
+    template <class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS multimap;
+};
+
+template <class _Tp, class _Compare, class _Allocator>
+__tree<_Tp, _Compare, _Allocator>::__tree(const value_compare& __comp)
+        _NOEXCEPT_(
+            is_nothrow_default_constructible<__node_allocator>::value &&
+            is_nothrow_copy_constructible<value_compare>::value)
+    : __pair3_(0, __comp)
+{
+    __begin_node() = __end_node();
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+__tree<_Tp, _Compare, _Allocator>::__tree(const allocator_type& __a)
+    : __begin_node_(__iter_pointer()),
+      __pair1_(__default_init_tag(), __node_allocator(__a)),
+      __pair3_(0, __default_init_tag())
+{
+    __begin_node() = __end_node();
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+__tree<_Tp, _Compare, _Allocator>::__tree(const value_compare& __comp,
+                                           const allocator_type& __a)
+    : __begin_node_(__iter_pointer()),
+      __pair1_(__default_init_tag(), __node_allocator(__a)),
+      __pair3_(0, __comp)
+{
+    __begin_node() = __end_node();
+}
+
+// Precondition:  size() != 0
+template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::__node_pointer
+__tree<_Tp, _Compare, _Allocator>::_DetachedTreeCache::__detach_from_tree(__tree *__t) _NOEXCEPT
+{
+    __node_pointer __cache = static_cast<__node_pointer>(__t->__begin_node());
+    __t->__begin_node() = __t->__end_node();
+    __t->__end_node()->__left_->__parent_ = nullptr;
+    __t->__end_node()->__left_ = nullptr;
+    __t->size() = 0;
+    // __cache->__left_ == nullptr
+    if (__cache->__right_ != nullptr)
+        __cache = static_cast<__node_pointer>(__cache->__right_);
+    // __cache->__left_ == nullptr
+    // __cache->__right_ == nullptr
+    return __cache;
+}
+
+// Precondition:  __cache != nullptr
+//    __cache->left_ == nullptr
+//    __cache->right_ == nullptr
+//    This is no longer a red-black tree
+template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::__node_pointer
+__tree<_Tp, _Compare, _Allocator>::_DetachedTreeCache::__detach_next(__node_pointer __cache) _NOEXCEPT
+{
+    if (__cache->__parent_ == nullptr)
+        return nullptr;
+    if (_VSTD::__tree_is_left_child(static_cast<__node_base_pointer>(__cache)))
+    {
+        __cache->__parent_->__left_ = nullptr;
+        __cache = static_cast<__node_pointer>(__cache->__parent_);
+        if (__cache->__right_ == nullptr)
+            return __cache;
+        return static_cast<__node_pointer>(_VSTD::__tree_leaf(__cache->__right_));
+    }
+    // __cache is right child
+    __cache->__parent_unsafe()->__right_ = nullptr;
+    __cache = static_cast<__node_pointer>(__cache->__parent_);
+    if (__cache->__left_ == nullptr)
+        return __cache;
+    return static_cast<__node_pointer>(_VSTD::__tree_leaf(__cache->__left_));
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+__tree<_Tp, _Compare, _Allocator>&
+__tree<_Tp, _Compare, _Allocator>::operator=(const __tree& __t)
+{
+    if (this != _VSTD::addressof(__t))
+    {
+        value_comp() = __t.value_comp();
+        __copy_assign_alloc(__t);
+        __assign_multi(__t.begin(), __t.end());
+    }
+    return *this;
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _ForwardIterator>
+void
+__tree<_Tp, _Compare, _Allocator>::__assign_unique(_ForwardIterator __first, _ForwardIterator __last)
+{
+    typedef iterator_traits<_ForwardIterator> _ITraits;
+    typedef typename _ITraits::value_type _ItValueType;
+    static_assert((is_same<_ItValueType, __container_value_type>::value),
+                  "__assign_unique may only be called with the containers value type");
+    static_assert(__is_cpp17_forward_iterator<_ForwardIterator>::value,
+                  "__assign_unique requires a forward iterator");
+    if (size() != 0)
+    {
+        _DetachedTreeCache __cache(this);
+          for (; __cache.__get() != nullptr && __first != __last; ++__first) {
+              if (__node_assign_unique(*__first, __cache.__get()).second)
+                  __cache.__advance();
+            }
+    }
+    for (; __first != __last; ++__first)
+        __insert_unique(*__first);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _InputIterator>
+void
+__tree<_Tp, _Compare, _Allocator>::__assign_multi(_InputIterator __first, _InputIterator __last)
+{
+    typedef iterator_traits<_InputIterator> _ITraits;
+    typedef typename _ITraits::value_type _ItValueType;
+    static_assert((is_same<_ItValueType, __container_value_type>::value ||
+                  is_same<_ItValueType, __node_value_type>::value),
+                  "__assign_multi may only be called with the containers value type"
+                  " or the nodes value type");
+    if (size() != 0)
+    {
+        _DetachedTreeCache __cache(this);
+        for (; __cache.__get() && __first != __last; ++__first) {
+            __cache.__get()->__value_ = *__first;
+            __node_insert_multi(__cache.__get());
+            __cache.__advance();
+        }
+    }
+    for (; __first != __last; ++__first)
+        __insert_multi(_NodeTypes::__get_value(*__first));
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+__tree<_Tp, _Compare, _Allocator>::__tree(const __tree& __t)
+    : __begin_node_(__iter_pointer()),
+      __pair1_(__default_init_tag(), __node_traits::select_on_container_copy_construction(__t.__node_alloc())),
+      __pair3_(0, __t.value_comp())
+{
+    __begin_node() = __end_node();
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+__tree<_Tp, _Compare, _Allocator>::__tree(__tree&& __t)
+    _NOEXCEPT_(
+        is_nothrow_move_constructible<__node_allocator>::value &&
+        is_nothrow_move_constructible<value_compare>::value)
+    : __begin_node_(_VSTD::move(__t.__begin_node_)),
+      __pair1_(_VSTD::move(__t.__pair1_)),
+      __pair3_(_VSTD::move(__t.__pair3_))
+{
+    if (size() == 0)
+        __begin_node() = __end_node();
+    else
+    {
+        __end_node()->__left_->__parent_ = static_cast<__parent_pointer>(__end_node());
+        __t.__begin_node() = __t.__end_node();
+        __t.__end_node()->__left_ = nullptr;
+        __t.size() = 0;
+    }
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+__tree<_Tp, _Compare, _Allocator>::__tree(__tree&& __t, const allocator_type& __a)
+    : __pair1_(__default_init_tag(), __node_allocator(__a)),
+      __pair3_(0, _VSTD::move(__t.value_comp()))
+{
+    if (__a == __t.__alloc())
+    {
+        if (__t.size() == 0)
+            __begin_node() = __end_node();
+        else
+        {
+            __begin_node() = __t.__begin_node();
+            __end_node()->__left_ = __t.__end_node()->__left_;
+            __end_node()->__left_->__parent_ = static_cast<__parent_pointer>(__end_node());
+            size() = __t.size();
+            __t.__begin_node() = __t.__end_node();
+            __t.__end_node()->__left_ = nullptr;
+            __t.size() = 0;
+        }
+    }
+    else
+    {
+        __begin_node() = __end_node();
+    }
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+void
+__tree<_Tp, _Compare, _Allocator>::__move_assign(__tree& __t, true_type)
+    _NOEXCEPT_(is_nothrow_move_assignable<value_compare>::value &&
+               is_nothrow_move_assignable<__node_allocator>::value)
+{
+    destroy(static_cast<__node_pointer>(__end_node()->__left_));
+    __begin_node_ = __t.__begin_node_;
+    __pair1_.first() = __t.__pair1_.first();
+    __move_assign_alloc(__t);
+    __pair3_ = _VSTD::move(__t.__pair3_);
+    if (size() == 0)
+        __begin_node() = __end_node();
+    else
+    {
+        __end_node()->__left_->__parent_ = static_cast<__parent_pointer>(__end_node());
+        __t.__begin_node() = __t.__end_node();
+        __t.__end_node()->__left_ = nullptr;
+        __t.size() = 0;
+    }
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+void
+__tree<_Tp, _Compare, _Allocator>::__move_assign(__tree& __t, false_type)
+{
+    if (__node_alloc() == __t.__node_alloc())
+        __move_assign(__t, true_type());
+    else
+    {
+        value_comp() = _VSTD::move(__t.value_comp());
+        const_iterator __e = end();
+        if (size() != 0)
+        {
+            _DetachedTreeCache __cache(this);
+            while (__cache.__get() != nullptr && __t.size() != 0) {
+              __cache.__get()->__value_ = _VSTD::move(__t.remove(__t.begin())->__value_);
+              __node_insert_multi(__cache.__get());
+              __cache.__advance();
+            }
+        }
+        while (__t.size() != 0)
+            __insert_multi(__e, _NodeTypes::__move(__t.remove(__t.begin())->__value_));
+    }
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+__tree<_Tp, _Compare, _Allocator>&
+__tree<_Tp, _Compare, _Allocator>::operator=(__tree&& __t)
+    _NOEXCEPT_(
+        __node_traits::propagate_on_container_move_assignment::value &&
+        is_nothrow_move_assignable<value_compare>::value &&
+        is_nothrow_move_assignable<__node_allocator>::value)
+
+{
+    __move_assign(__t, integral_constant<bool,
+                  __node_traits::propagate_on_container_move_assignment::value>());
+    return *this;
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+__tree<_Tp, _Compare, _Allocator>::~__tree()
+{
+    static_assert((is_copy_constructible<value_compare>::value),
+                 "Comparator must be copy-constructible.");
+  destroy(__root());
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+void
+__tree<_Tp, _Compare, _Allocator>::destroy(__node_pointer __nd) _NOEXCEPT
+{
+    if (__nd != nullptr)
+    {
+        destroy(static_cast<__node_pointer>(__nd->__left_));
+        destroy(static_cast<__node_pointer>(__nd->__right_));
+        __node_allocator& __na = __node_alloc();
+        __node_traits::destroy(__na, _NodeTypes::__get_ptr(__nd->__value_));
+        __node_traits::deallocate(__na, __nd, 1);
+    }
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+void
+__tree<_Tp, _Compare, _Allocator>::swap(__tree& __t)
+#if _LIBCPP_STD_VER <= 11
+        _NOEXCEPT_(
+            __is_nothrow_swappable<value_compare>::value
+            && (!__node_traits::propagate_on_container_swap::value ||
+                 __is_nothrow_swappable<__node_allocator>::value)
+            )
+#else
+        _NOEXCEPT_(__is_nothrow_swappable<value_compare>::value)
+#endif
+{
+    using _VSTD::swap;
+    swap(__begin_node_, __t.__begin_node_);
+    swap(__pair1_.first(), __t.__pair1_.first());
+    _VSTD::__swap_allocator(__node_alloc(), __t.__node_alloc());
+    __pair3_.swap(__t.__pair3_);
+    if (size() == 0)
+        __begin_node() = __end_node();
+    else
+        __end_node()->__left_->__parent_ = static_cast<__parent_pointer>(__end_node());
+    if (__t.size() == 0)
+        __t.__begin_node() = __t.__end_node();
+    else
+        __t.__end_node()->__left_->__parent_ = static_cast<__parent_pointer>(__t.__end_node());
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+void
+__tree<_Tp, _Compare, _Allocator>::clear() _NOEXCEPT
+{
+    destroy(__root());
+    size() = 0;
+    __begin_node() = __end_node();
+    __end_node()->__left_ = nullptr;
+}
+
+// Find lower_bound place to insert
+// Set __parent to parent of null leaf
+// Return reference to null leaf
+template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::__node_base_pointer&
+__tree<_Tp, _Compare, _Allocator>::__find_leaf_low(__parent_pointer& __parent,
+                                                   const key_type& __v)
+{
+    __node_pointer __nd = __root();
+    if (__nd != nullptr)
+    {
+        while (true)
+        {
+            if (value_comp()(__nd->__value_, __v))
+            {
+                if (__nd->__right_ != nullptr)
+                    __nd = static_cast<__node_pointer>(__nd->__right_);
+                else
+                {
+                    __parent = static_cast<__parent_pointer>(__nd);
+                    return __nd->__right_;
+                }
+            }
+            else
+            {
+                if (__nd->__left_ != nullptr)
+                    __nd = static_cast<__node_pointer>(__nd->__left_);
+                else
+                {
+                    __parent = static_cast<__parent_pointer>(__nd);
+                    return __parent->__left_;
+                }
+            }
+        }
+    }
+    __parent = static_cast<__parent_pointer>(__end_node());
+    return __parent->__left_;
+}
+
+// Find upper_bound place to insert
+// Set __parent to parent of null leaf
+// Return reference to null leaf
+template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::__node_base_pointer&
+__tree<_Tp, _Compare, _Allocator>::__find_leaf_high(__parent_pointer& __parent,
+                                                    const key_type& __v)
+{
+    __node_pointer __nd = __root();
+    if (__nd != nullptr)
+    {
+        while (true)
+        {
+            if (value_comp()(__v, __nd->__value_))
+            {
+                if (__nd->__left_ != nullptr)
+                    __nd = static_cast<__node_pointer>(__nd->__left_);
+                else
+                {
+                    __parent = static_cast<__parent_pointer>(__nd);
+                    return __parent->__left_;
+                }
+            }
+            else
+            {
+                if (__nd->__right_ != nullptr)
+                    __nd = static_cast<__node_pointer>(__nd->__right_);
+                else
+                {
+                    __parent = static_cast<__parent_pointer>(__nd);
+                    return __nd->__right_;
+                }
+            }
+        }
+    }
+    __parent = static_cast<__parent_pointer>(__end_node());
+    return __parent->__left_;
+}
+
+// Find leaf place to insert closest to __hint
+// First check prior to __hint.
+// Next check after __hint.
+// Next do O(log N) search.
+// Set __parent to parent of null leaf
+// Return reference to null leaf
+template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::__node_base_pointer&
+__tree<_Tp, _Compare, _Allocator>::__find_leaf(const_iterator __hint,
+                                               __parent_pointer& __parent,
+                                               const key_type& __v)
+{
+    if (__hint == end() || !value_comp()(*__hint, __v))  // check before
+    {
+        // __v <= *__hint
+        const_iterator __prior = __hint;
+        if (__prior == begin() || !value_comp()(__v, *--__prior))
+        {
+            // *prev(__hint) <= __v <= *__hint
+            if (__hint.__ptr_->__left_ == nullptr)
+            {
+                __parent = static_cast<__parent_pointer>(__hint.__ptr_);
+                return __parent->__left_;
+            }
+            else
+            {
+                __parent = static_cast<__parent_pointer>(__prior.__ptr_);
+                return static_cast<__node_base_pointer>(__prior.__ptr_)->__right_;
+            }
+        }
+        // __v < *prev(__hint)
+        return __find_leaf_high(__parent, __v);
+    }
+    // else __v > *__hint
+    return __find_leaf_low(__parent, __v);
+}
+
+// Find place to insert if __v doesn't exist
+// Set __parent to parent of null leaf
+// Return reference to null leaf
+// If __v exists, set parent to node of __v and return reference to node of __v
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+typename __tree<_Tp, _Compare, _Allocator>::__node_base_pointer&
+__tree<_Tp, _Compare, _Allocator>::__find_equal(__parent_pointer& __parent,
+                                                const _Key& __v)
+{
+    __node_pointer __nd = __root();
+    __node_base_pointer* __nd_ptr = __root_ptr();
+    if (__nd != nullptr)
+    {
+        while (true)
+        {
+            if (value_comp()(__v, __nd->__value_))
+            {
+                if (__nd->__left_ != nullptr) {
+                    __nd_ptr = _VSTD::addressof(__nd->__left_);
+                    __nd = static_cast<__node_pointer>(__nd->__left_);
+                } else {
+                    __parent = static_cast<__parent_pointer>(__nd);
+                    return __parent->__left_;
+                }
+            }
+            else if (value_comp()(__nd->__value_, __v))
+            {
+                if (__nd->__right_ != nullptr) {
+                    __nd_ptr = _VSTD::addressof(__nd->__right_);
+                    __nd = static_cast<__node_pointer>(__nd->__right_);
+                } else {
+                    __parent = static_cast<__parent_pointer>(__nd);
+                    return __nd->__right_;
+                }
+            }
+            else
+            {
+                __parent = static_cast<__parent_pointer>(__nd);
+                return *__nd_ptr;
+            }
+        }
+    }
+    __parent = static_cast<__parent_pointer>(__end_node());
+    return __parent->__left_;
+}
+
+// Find place to insert if __v doesn't exist
+// First check prior to __hint.
+// Next check after __hint.
+// Next do O(log N) search.
+// Set __parent to parent of null leaf
+// Return reference to null leaf
+// If __v exists, set parent to node of __v and return reference to node of __v
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+typename __tree<_Tp, _Compare, _Allocator>::__node_base_pointer&
+__tree<_Tp, _Compare, _Allocator>::__find_equal(const_iterator __hint,
+                                                __parent_pointer& __parent,
+                                                __node_base_pointer& __dummy,
+                                                const _Key& __v)
+{
+    if (__hint == end() || value_comp()(__v, *__hint))  // check before
+    {
+        // __v < *__hint
+        const_iterator __prior = __hint;
+        if (__prior == begin() || value_comp()(*--__prior, __v))
+        {
+            // *prev(__hint) < __v < *__hint
+            if (__hint.__ptr_->__left_ == nullptr)
+            {
+                __parent = static_cast<__parent_pointer>(__hint.__ptr_);
+                return __parent->__left_;
+            }
+            else
+            {
+                __parent = static_cast<__parent_pointer>(__prior.__ptr_);
+                return static_cast<__node_base_pointer>(__prior.__ptr_)->__right_;
+            }
+        }
+        // __v <= *prev(__hint)
+        return __find_equal(__parent, __v);
+    }
+    else if (value_comp()(*__hint, __v))  // check after
+    {
+        // *__hint < __v
+        const_iterator __next = _VSTD::next(__hint);
+        if (__next == end() || value_comp()(__v, *__next))
+        {
+            // *__hint < __v < *_VSTD::next(__hint)
+            if (__hint.__get_np()->__right_ == nullptr)
+            {
+                __parent = static_cast<__parent_pointer>(__hint.__ptr_);
+                return static_cast<__node_base_pointer>(__hint.__ptr_)->__right_;
+            }
+            else
+            {
+                __parent = static_cast<__parent_pointer>(__next.__ptr_);
+                return __parent->__left_;
+            }
+        }
+        // *next(__hint) <= __v
+        return __find_equal(__parent, __v);
+    }
+    // else __v == *__hint
+    __parent = static_cast<__parent_pointer>(__hint.__ptr_);
+    __dummy = static_cast<__node_base_pointer>(__hint.__ptr_);
+    return __dummy;
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+void __tree<_Tp, _Compare, _Allocator>::__insert_node_at(
+    __parent_pointer __parent, __node_base_pointer& __child,
+    __node_base_pointer __new_node) _NOEXCEPT
+{
+    __new_node->__left_   = nullptr;
+    __new_node->__right_  = nullptr;
+    __new_node->__parent_ = __parent;
+    // __new_node->__is_black_ is initialized in __tree_balance_after_insert
+    __child = __new_node;
+    if (__begin_node()->__left_ != nullptr)
+        __begin_node() = static_cast<__iter_pointer>(__begin_node()->__left_);
+    _VSTD::__tree_balance_after_insert(__end_node()->__left_, __child);
+    ++size();
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key, class... _Args>
+pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
+__tree<_Tp, _Compare, _Allocator>::__emplace_unique_key_args(_Key const& __k, _Args&&... __args)
+{
+    __parent_pointer __parent;
+    __node_base_pointer& __child = __find_equal(__parent, __k);
+    __node_pointer __r = static_cast<__node_pointer>(__child);
+    bool __inserted = false;
+    if (__child == nullptr)
+    {
+        __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
+        __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
+        __r = __h.release();
+        __inserted = true;
+    }
+    return pair<iterator, bool>(iterator(__r), __inserted);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key, class... _Args>
+pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
+__tree<_Tp, _Compare, _Allocator>::__emplace_hint_unique_key_args(
+    const_iterator __p, _Key const& __k, _Args&&... __args)
+{
+    __parent_pointer __parent;
+    __node_base_pointer __dummy;
+    __node_base_pointer& __child = __find_equal(__p, __parent, __dummy, __k);
+    __node_pointer __r = static_cast<__node_pointer>(__child);
+    bool __inserted = false;
+    if (__child == nullptr)
+    {
+        __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
+        __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
+        __r = __h.release();
+        __inserted = true;
+    }
+    return pair<iterator, bool>(iterator(__r), __inserted);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class ..._Args>
+typename __tree<_Tp, _Compare, _Allocator>::__node_holder
+__tree<_Tp, _Compare, _Allocator>::__construct_node(_Args&& ...__args)
+{
+    static_assert(!__is_tree_value_type<_Args...>::value,
+                  "Cannot construct from __value_type");
+    __node_allocator& __na = __node_alloc();
+    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
+    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), _VSTD::forward<_Args>(__args)...);
+    __h.get_deleter().__value_constructed = true;
+    return __h;
+}
+
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class... _Args>
+pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
+__tree<_Tp, _Compare, _Allocator>::__emplace_unique_impl(_Args&&... __args)
+{
+    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
+    __parent_pointer __parent;
+    __node_base_pointer& __child = __find_equal(__parent, __h->__value_);
+    __node_pointer __r = static_cast<__node_pointer>(__child);
+    bool __inserted = false;
+    if (__child == nullptr)
+    {
+        __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
+        __r = __h.release();
+        __inserted = true;
+    }
+    return pair<iterator, bool>(iterator(__r), __inserted);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class... _Args>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__emplace_hint_unique_impl(const_iterator __p, _Args&&... __args)
+{
+    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
+    __parent_pointer __parent;
+    __node_base_pointer __dummy;
+    __node_base_pointer& __child = __find_equal(__p, __parent, __dummy, __h->__value_);
+    __node_pointer __r = static_cast<__node_pointer>(__child);
+    if (__child == nullptr)
+    {
+        __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
+        __r = __h.release();
+    }
+    return iterator(__r);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class... _Args>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__emplace_multi(_Args&&... __args)
+{
+    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
+    __parent_pointer __parent;
+    __node_base_pointer& __child = __find_leaf_high(__parent, _NodeTypes::__get_key(__h->__value_));
+    __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
+    return iterator(static_cast<__node_pointer>(__h.release()));
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class... _Args>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__emplace_hint_multi(const_iterator __p,
+                                                        _Args&&... __args)
+{
+    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
+    __parent_pointer __parent;
+    __node_base_pointer& __child = __find_leaf(__p, __parent, _NodeTypes::__get_key(__h->__value_));
+    __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
+    return iterator(static_cast<__node_pointer>(__h.release()));
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+pair<typename __tree<_Tp, _Compare, _Allocator>::iterator, bool>
+__tree<_Tp, _Compare, _Allocator>::__node_assign_unique(const __container_value_type& __v, __node_pointer __nd)
+{
+    __parent_pointer __parent;
+    __node_base_pointer& __child = __find_equal(__parent, _NodeTypes::__get_key(__v));
+    __node_pointer __r = static_cast<__node_pointer>(__child);
+    bool __inserted = false;
+    if (__child == nullptr)
+    {
+        __nd->__value_ = __v;
+        __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__nd));
+        __r = __nd;
+        __inserted = true;
+    }
+    return pair<iterator, bool>(iterator(__r), __inserted);
+}
+
+
+template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__node_insert_multi(__node_pointer __nd)
+{
+    __parent_pointer __parent;
+    __node_base_pointer& __child = __find_leaf_high(__parent, _NodeTypes::__get_key(__nd->__value_));
+    __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__nd));
+    return iterator(__nd);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__node_insert_multi(const_iterator __p,
+                                                       __node_pointer __nd)
+{
+    __parent_pointer __parent;
+    __node_base_pointer& __child = __find_leaf(__p, __parent, _NodeTypes::__get_key(__nd->__value_));
+    __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__nd));
+    return iterator(__nd);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__remove_node_pointer(__node_pointer __ptr) _NOEXCEPT
+{
+    iterator __r(__ptr);
+    ++__r;
+    if (__begin_node() == __ptr)
+        __begin_node() = __r.__ptr_;
+    --size();
+    _VSTD::__tree_remove(__end_node()->__left_,
+                         static_cast<__node_base_pointer>(__ptr));
+    return __r;
+}
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, class _Compare, class _Allocator>
+template <class _NodeHandle, class _InsertReturnType>
+_LIBCPP_INLINE_VISIBILITY
+_InsertReturnType
+__tree<_Tp, _Compare, _Allocator>::__node_handle_insert_unique(
+    _NodeHandle&& __nh)
+{
+    if (__nh.empty())
+        return _InsertReturnType{end(), false, _NodeHandle()};
+
+    __node_pointer __ptr = __nh.__ptr_;
+    __parent_pointer __parent;
+    __node_base_pointer& __child = __find_equal(__parent,
+                                                __ptr->__value_);
+    if (__child != nullptr)
+        return _InsertReturnType{
+            iterator(static_cast<__node_pointer>(__child)),
+            false, _VSTD::move(__nh)};
+
+    __insert_node_at(__parent, __child,
+                     static_cast<__node_base_pointer>(__ptr));
+    __nh.__release_ptr();
+    return _InsertReturnType{iterator(__ptr), true, _NodeHandle()};
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _NodeHandle>
+_LIBCPP_INLINE_VISIBILITY
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__node_handle_insert_unique(
+    const_iterator __hint, _NodeHandle&& __nh)
+{
+    if (__nh.empty())
+        return end();
+
+    __node_pointer __ptr = __nh.__ptr_;
+    __parent_pointer __parent;
+    __node_base_pointer __dummy;
+    __node_base_pointer& __child = __find_equal(__hint, __parent, __dummy,
+                                                __ptr->__value_);
+    __node_pointer __r = static_cast<__node_pointer>(__child);
+    if (__child == nullptr)
+    {
+        __insert_node_at(__parent, __child,
+                         static_cast<__node_base_pointer>(__ptr));
+        __r = __ptr;
+        __nh.__release_ptr();
+    }
+    return iterator(__r);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _NodeHandle>
+_LIBCPP_INLINE_VISIBILITY
+_NodeHandle
+__tree<_Tp, _Compare, _Allocator>::__node_handle_extract(key_type const& __key)
+{
+    iterator __it = find(__key);
+    if (__it == end())
+        return _NodeHandle();
+    return __node_handle_extract<_NodeHandle>(__it);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _NodeHandle>
+_LIBCPP_INLINE_VISIBILITY
+_NodeHandle
+__tree<_Tp, _Compare, _Allocator>::__node_handle_extract(const_iterator __p)
+{
+    __node_pointer __np = __p.__get_np();
+    __remove_node_pointer(__np);
+    return _NodeHandle(__np, __alloc());
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Tree>
+_LIBCPP_INLINE_VISIBILITY
+void
+__tree<_Tp, _Compare, _Allocator>::__node_handle_merge_unique(_Tree& __source)
+{
+    static_assert(is_same<typename _Tree::__node_pointer, __node_pointer>::value, "");
+
+    for (typename _Tree::iterator __i = __source.begin();
+         __i != __source.end();)
+    {
+        __node_pointer __src_ptr = __i.__get_np();
+        __parent_pointer __parent;
+        __node_base_pointer& __child =
+            __find_equal(__parent, _NodeTypes::__get_key(__src_ptr->__value_));
+        ++__i;
+        if (__child != nullptr)
+            continue;
+        __source.__remove_node_pointer(__src_ptr);
+        __insert_node_at(__parent, __child,
+                         static_cast<__node_base_pointer>(__src_ptr));
+    }
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _NodeHandle>
+_LIBCPP_INLINE_VISIBILITY
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__node_handle_insert_multi(_NodeHandle&& __nh)
+{
+    if (__nh.empty())
+        return end();
+    __node_pointer __ptr = __nh.__ptr_;
+    __parent_pointer __parent;
+    __node_base_pointer& __child = __find_leaf_high(
+        __parent, _NodeTypes::__get_key(__ptr->__value_));
+    __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__ptr));
+    __nh.__release_ptr();
+    return iterator(__ptr);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _NodeHandle>
+_LIBCPP_INLINE_VISIBILITY
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__node_handle_insert_multi(
+    const_iterator __hint, _NodeHandle&& __nh)
+{
+    if (__nh.empty())
+        return end();
+
+    __node_pointer __ptr = __nh.__ptr_;
+    __parent_pointer __parent;
+    __node_base_pointer& __child = __find_leaf(__hint, __parent,
+                                               _NodeTypes::__get_key(__ptr->__value_));
+    __insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__ptr));
+    __nh.__release_ptr();
+    return iterator(__ptr);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Tree>
+_LIBCPP_INLINE_VISIBILITY
+void
+__tree<_Tp, _Compare, _Allocator>::__node_handle_merge_multi(_Tree& __source)
+{
+    static_assert(is_same<typename _Tree::__node_pointer, __node_pointer>::value, "");
+
+    for (typename _Tree::iterator __i = __source.begin();
+         __i != __source.end();)
+    {
+        __node_pointer __src_ptr = __i.__get_np();
+        __parent_pointer __parent;
+        __node_base_pointer& __child = __find_leaf_high(
+            __parent, _NodeTypes::__get_key(__src_ptr->__value_));
+        ++__i;
+        __source.__remove_node_pointer(__src_ptr);
+        __insert_node_at(__parent, __child,
+                         static_cast<__node_base_pointer>(__src_ptr));
+    }
+}
+
+#endif // _LIBCPP_STD_VER > 14
+
+template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::erase(const_iterator __p)
+{
+    __node_pointer __np = __p.__get_np();
+    iterator __r = __remove_node_pointer(__np);
+    __node_allocator& __na = __node_alloc();
+    __node_traits::destroy(__na, _NodeTypes::__get_ptr(
+        const_cast<__node_value_type&>(*__p)));
+    __node_traits::deallocate(__na, __np, 1);
+    return __r;
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::erase(const_iterator __f, const_iterator __l)
+{
+    while (__f != __l)
+        __f = erase(__f);
+    return iterator(__l.__ptr_);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+typename __tree<_Tp, _Compare, _Allocator>::size_type
+__tree<_Tp, _Compare, _Allocator>::__erase_unique(const _Key& __k)
+{
+    iterator __i = find(__k);
+    if (__i == end())
+        return 0;
+    erase(__i);
+    return 1;
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+typename __tree<_Tp, _Compare, _Allocator>::size_type
+__tree<_Tp, _Compare, _Allocator>::__erase_multi(const _Key& __k)
+{
+    pair<iterator, iterator> __p = __equal_range_multi(__k);
+    size_type __r = 0;
+    for (; __p.first != __p.second; ++__r)
+        __p.first = erase(__p.first);
+    return __r;
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::find(const _Key& __v)
+{
+    iterator __p = __lower_bound(__v, __root(), __end_node());
+    if (__p != end() && !value_comp()(__v, *__p))
+        return __p;
+    return end();
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+typename __tree<_Tp, _Compare, _Allocator>::const_iterator
+__tree<_Tp, _Compare, _Allocator>::find(const _Key& __v) const
+{
+    const_iterator __p = __lower_bound(__v, __root(), __end_node());
+    if (__p != end() && !value_comp()(__v, *__p))
+        return __p;
+    return end();
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+typename __tree<_Tp, _Compare, _Allocator>::size_type
+__tree<_Tp, _Compare, _Allocator>::__count_unique(const _Key& __k) const
+{
+    __node_pointer __rt = __root();
+    while (__rt != nullptr)
+    {
+        if (value_comp()(__k, __rt->__value_))
+        {
+            __rt = static_cast<__node_pointer>(__rt->__left_);
+        }
+        else if (value_comp()(__rt->__value_, __k))
+            __rt = static_cast<__node_pointer>(__rt->__right_);
+        else
+            return 1;
+    }
+    return 0;
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+typename __tree<_Tp, _Compare, _Allocator>::size_type
+__tree<_Tp, _Compare, _Allocator>::__count_multi(const _Key& __k) const
+{
+    __iter_pointer __result = __end_node();
+    __node_pointer __rt = __root();
+    while (__rt != nullptr)
+    {
+        if (value_comp()(__k, __rt->__value_))
+        {
+            __result = static_cast<__iter_pointer>(__rt);
+            __rt = static_cast<__node_pointer>(__rt->__left_);
+        }
+        else if (value_comp()(__rt->__value_, __k))
+            __rt = static_cast<__node_pointer>(__rt->__right_);
+        else
+            return _VSTD::distance(
+                __lower_bound(__k, static_cast<__node_pointer>(__rt->__left_), static_cast<__iter_pointer>(__rt)),
+                __upper_bound(__k, static_cast<__node_pointer>(__rt->__right_), __result)
+            );
+    }
+    return 0;
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__lower_bound(const _Key& __v,
+                                                 __node_pointer __root,
+                                                 __iter_pointer __result)
+{
+    while (__root != nullptr)
+    {
+        if (!value_comp()(__root->__value_, __v))
+        {
+            __result = static_cast<__iter_pointer>(__root);
+            __root = static_cast<__node_pointer>(__root->__left_);
+        }
+        else
+            __root = static_cast<__node_pointer>(__root->__right_);
+    }
+    return iterator(__result);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+typename __tree<_Tp, _Compare, _Allocator>::const_iterator
+__tree<_Tp, _Compare, _Allocator>::__lower_bound(const _Key& __v,
+                                                 __node_pointer __root,
+                                                 __iter_pointer __result) const
+{
+    while (__root != nullptr)
+    {
+        if (!value_comp()(__root->__value_, __v))
+        {
+            __result = static_cast<__iter_pointer>(__root);
+            __root = static_cast<__node_pointer>(__root->__left_);
+        }
+        else
+            __root = static_cast<__node_pointer>(__root->__right_);
+    }
+    return const_iterator(__result);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+typename __tree<_Tp, _Compare, _Allocator>::iterator
+__tree<_Tp, _Compare, _Allocator>::__upper_bound(const _Key& __v,
+                                                 __node_pointer __root,
+                                                 __iter_pointer __result)
+{
+    while (__root != nullptr)
+    {
+        if (value_comp()(__v, __root->__value_))
+        {
+            __result = static_cast<__iter_pointer>(__root);
+            __root = static_cast<__node_pointer>(__root->__left_);
+        }
+        else
+            __root = static_cast<__node_pointer>(__root->__right_);
+    }
+    return iterator(__result);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+typename __tree<_Tp, _Compare, _Allocator>::const_iterator
+__tree<_Tp, _Compare, _Allocator>::__upper_bound(const _Key& __v,
+                                                 __node_pointer __root,
+                                                 __iter_pointer __result) const
+{
+    while (__root != nullptr)
+    {
+        if (value_comp()(__v, __root->__value_))
+        {
+            __result = static_cast<__iter_pointer>(__root);
+            __root = static_cast<__node_pointer>(__root->__left_);
+        }
+        else
+            __root = static_cast<__node_pointer>(__root->__right_);
+    }
+    return const_iterator(__result);
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+pair<typename __tree<_Tp, _Compare, _Allocator>::iterator,
+     typename __tree<_Tp, _Compare, _Allocator>::iterator>
+__tree<_Tp, _Compare, _Allocator>::__equal_range_unique(const _Key& __k)
+{
+    typedef pair<iterator, iterator> _Pp;
+    __iter_pointer __result = __end_node();
+    __node_pointer __rt = __root();
+    while (__rt != nullptr)
+    {
+        if (value_comp()(__k, __rt->__value_))
+        {
+            __result = static_cast<__iter_pointer>(__rt);
+            __rt = static_cast<__node_pointer>(__rt->__left_);
+        }
+        else if (value_comp()(__rt->__value_, __k))
+            __rt = static_cast<__node_pointer>(__rt->__right_);
+        else
+            return _Pp(iterator(__rt),
+                      iterator(
+                          __rt->__right_ != nullptr ?
+                              static_cast<__iter_pointer>(_VSTD::__tree_min(__rt->__right_))
+                            : __result));
+    }
+    return _Pp(iterator(__result), iterator(__result));
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+pair<typename __tree<_Tp, _Compare, _Allocator>::const_iterator,
+     typename __tree<_Tp, _Compare, _Allocator>::const_iterator>
+__tree<_Tp, _Compare, _Allocator>::__equal_range_unique(const _Key& __k) const
+{
+    typedef pair<const_iterator, const_iterator> _Pp;
+    __iter_pointer __result = __end_node();
+    __node_pointer __rt = __root();
+    while (__rt != nullptr)
+    {
+        if (value_comp()(__k, __rt->__value_))
+        {
+            __result = static_cast<__iter_pointer>(__rt);
+            __rt = static_cast<__node_pointer>(__rt->__left_);
+        }
+        else if (value_comp()(__rt->__value_, __k))
+            __rt = static_cast<__node_pointer>(__rt->__right_);
+        else
+            return _Pp(const_iterator(__rt),
+                      const_iterator(
+                          __rt->__right_ != nullptr ?
+                              static_cast<__iter_pointer>(_VSTD::__tree_min(__rt->__right_))
+                            : __result));
+    }
+    return _Pp(const_iterator(__result), const_iterator(__result));
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+pair<typename __tree<_Tp, _Compare, _Allocator>::iterator,
+     typename __tree<_Tp, _Compare, _Allocator>::iterator>
+__tree<_Tp, _Compare, _Allocator>::__equal_range_multi(const _Key& __k)
+{
+    typedef pair<iterator, iterator> _Pp;
+    __iter_pointer __result = __end_node();
+    __node_pointer __rt = __root();
+    while (__rt != nullptr)
+    {
+        if (value_comp()(__k, __rt->__value_))
+        {
+            __result = static_cast<__iter_pointer>(__rt);
+            __rt = static_cast<__node_pointer>(__rt->__left_);
+        }
+        else if (value_comp()(__rt->__value_, __k))
+            __rt = static_cast<__node_pointer>(__rt->__right_);
+        else
+            return _Pp(__lower_bound(__k, static_cast<__node_pointer>(__rt->__left_), static_cast<__iter_pointer>(__rt)),
+                      __upper_bound(__k, static_cast<__node_pointer>(__rt->__right_), __result));
+    }
+    return _Pp(iterator(__result), iterator(__result));
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+template <class _Key>
+pair<typename __tree<_Tp, _Compare, _Allocator>::const_iterator,
+     typename __tree<_Tp, _Compare, _Allocator>::const_iterator>
+__tree<_Tp, _Compare, _Allocator>::__equal_range_multi(const _Key& __k) const
+{
+    typedef pair<const_iterator, const_iterator> _Pp;
+    __iter_pointer __result = __end_node();
+    __node_pointer __rt = __root();
+    while (__rt != nullptr)
+    {
+        if (value_comp()(__k, __rt->__value_))
+        {
+            __result = static_cast<__iter_pointer>(__rt);
+            __rt = static_cast<__node_pointer>(__rt->__left_);
+        }
+        else if (value_comp()(__rt->__value_, __k))
+            __rt = static_cast<__node_pointer>(__rt->__right_);
+        else
+            return _Pp(__lower_bound(__k, static_cast<__node_pointer>(__rt->__left_), static_cast<__iter_pointer>(__rt)),
+                      __upper_bound(__k, static_cast<__node_pointer>(__rt->__right_), __result));
+    }
+    return _Pp(const_iterator(__result), const_iterator(__result));
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+typename __tree<_Tp, _Compare, _Allocator>::__node_holder
+__tree<_Tp, _Compare, _Allocator>::remove(const_iterator __p) _NOEXCEPT
+{
+    __node_pointer __np = __p.__get_np();
+    if (__begin_node() == __p.__ptr_)
+    {
+        if (__np->__right_ != nullptr)
+            __begin_node() = static_cast<__iter_pointer>(__np->__right_);
+        else
+            __begin_node() = static_cast<__iter_pointer>(__np->__parent_);
+    }
+    --size();
+    _VSTD::__tree_remove(__end_node()->__left_,
+                         static_cast<__node_base_pointer>(__np));
+    return __node_holder(__np, _Dp(__node_alloc(), true));
+}
+
+template <class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(__tree<_Tp, _Compare, _Allocator>& __x,
+     __tree<_Tp, _Compare, _Allocator>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___TREE
diff --git a/contrib/libs/cxxsupp/libcxx/include/__tuple b/contrib/libs/cxxsupp/libcxx/include/__tuple
new file mode 100644
index 00000000000..08f4dd5efa4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__tuple
@@ -0,0 +1,636 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___TUPLE
+#define _LIBCPP___TUPLE
+
+#include <__config>
+#include <cstddef>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp> class _LIBCPP_TEMPLATE_VIS tuple_size;
+
+#if !defined(_LIBCPP_CXX03_LANG)
+template <class _Tp, class...>
+using __enable_if_tuple_size_imp = _Tp;
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS tuple_size<__enable_if_tuple_size_imp<
+    const _Tp,
+    typename enable_if<!is_volatile<_Tp>::value>::type,
+    integral_constant<size_t, sizeof(tuple_size<_Tp>)>>>
+    : public integral_constant<size_t, tuple_size<_Tp>::value> {};
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS tuple_size<__enable_if_tuple_size_imp<
+    volatile _Tp,
+    typename enable_if<!is_const<_Tp>::value>::type,
+    integral_constant<size_t, sizeof(tuple_size<_Tp>)>>>
+    : public integral_constant<size_t, tuple_size<_Tp>::value> {};
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS tuple_size<__enable_if_tuple_size_imp<
+    const volatile _Tp,
+    integral_constant<size_t, sizeof(tuple_size<_Tp>)>>>
+    : public integral_constant<size_t, tuple_size<_Tp>::value> {};
+
+#else
+template <class _Tp> class _LIBCPP_TEMPLATE_VIS tuple_size<const _Tp> : public tuple_size<_Tp> {};
+template <class _Tp> class _LIBCPP_TEMPLATE_VIS tuple_size<volatile _Tp> : public tuple_size<_Tp> {};
+template <class _Tp> class _LIBCPP_TEMPLATE_VIS tuple_size<const volatile _Tp> : public tuple_size<_Tp> {};
+#endif
+
+template <size_t _Ip, class _Tp> struct _LIBCPP_TEMPLATE_VIS tuple_element;
+
+template <size_t _Ip, class _Tp>
+struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, const _Tp>
+{
+    typedef _LIBCPP_NODEBUG typename add_const<typename tuple_element<_Ip, _Tp>::type>::type type;
+};
+
+template <size_t _Ip, class _Tp>
+struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, volatile _Tp>
+{
+    typedef _LIBCPP_NODEBUG typename add_volatile<typename tuple_element<_Ip, _Tp>::type>::type type;
+};
+
+template <size_t _Ip, class _Tp>
+struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, const volatile _Tp>
+{
+    typedef _LIBCPP_NODEBUG typename add_cv<typename tuple_element<_Ip, _Tp>::type>::type type;
+};
+
+template <class _Tp> struct __tuple_like : false_type {};
+
+template <class _Tp> struct __tuple_like<const _Tp> : public __tuple_like<_Tp> {};
+template <class _Tp> struct __tuple_like<volatile _Tp> : public __tuple_like<_Tp> {};
+template <class _Tp> struct __tuple_like<const volatile _Tp> : public __tuple_like<_Tp> {};
+
+// tuple specializations
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <size_t...> struct __tuple_indices {};
+
+template <class _IdxType, _IdxType... _Values>
+struct __integer_sequence {
+  template <size_t _Sp>
+  using __to_tuple_indices = __tuple_indices<(_Values + _Sp)...>;
+};
+
+#if defined(__CUDACC__) || !__has_builtin(__make_integer_seq) || defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
+namespace __detail {
+
+template<typename _Tp, size_t ..._Extra> struct __repeat;
+template<typename _Tp, _Tp ..._Np, size_t ..._Extra> struct __repeat<__integer_sequence<_Tp, _Np...>, _Extra...> {
+  typedef _LIBCPP_NODEBUG __integer_sequence<_Tp,
+                           _Np...,
+                           sizeof...(_Np) + _Np...,
+                           2 * sizeof...(_Np) + _Np...,
+                           3 * sizeof...(_Np) + _Np...,
+                           4 * sizeof...(_Np) + _Np...,
+                           5 * sizeof...(_Np) + _Np...,
+                           6 * sizeof...(_Np) + _Np...,
+                           7 * sizeof...(_Np) + _Np...,
+                           _Extra...> type;
+};
+
+template<size_t _Np> struct __parity;
+template<size_t _Np> struct __make : __parity<_Np % 8>::template __pmake<_Np> {};
+
+template<> struct __make<0> { typedef __integer_sequence<size_t> type; };
+template<> struct __make<1> { typedef __integer_sequence<size_t, 0> type; };
+template<> struct __make<2> { typedef __integer_sequence<size_t, 0, 1> type; };
+template<> struct __make<3> { typedef __integer_sequence<size_t, 0, 1, 2> type; };
+template<> struct __make<4> { typedef __integer_sequence<size_t, 0, 1, 2, 3> type; };
+template<> struct __make<5> { typedef __integer_sequence<size_t, 0, 1, 2, 3, 4> type; };
+template<> struct __make<6> { typedef __integer_sequence<size_t, 0, 1, 2, 3, 4, 5> type; };
+template<> struct __make<7> { typedef __integer_sequence<size_t, 0, 1, 2, 3, 4, 5, 6> type; };
+
+template<> struct __parity<0> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type> {}; };
+template<> struct __parity<1> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 1> {}; };
+template<> struct __parity<2> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 2, _Np - 1> {}; };
+template<> struct __parity<3> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 3, _Np - 2, _Np - 1> {}; };
+template<> struct __parity<4> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
+template<> struct __parity<5> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
+template<> struct __parity<6> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
+template<> struct __parity<7> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 7, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
+
+} // namespace detail
+
+#endif // !__has_builtin(__make_integer_seq) || defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
+
+#if __has_builtin(__make_integer_seq) && !defined(__CUDACC__)
+template <size_t _Ep, size_t _Sp>
+using __make_indices_imp =
+    typename __make_integer_seq<__integer_sequence, size_t, _Ep - _Sp>::template
+    __to_tuple_indices<_Sp>;
+#else
+template <size_t _Ep, size_t _Sp>
+using __make_indices_imp =
+    typename __detail::__make<_Ep - _Sp>::type::template __to_tuple_indices<_Sp>;
+
+#endif
+
+template <size_t _Ep, size_t _Sp = 0>
+struct __make_tuple_indices
+{
+    static_assert(_Sp <= _Ep, "__make_tuple_indices input error");
+    typedef __make_indices_imp<_Ep, _Sp> type;
+};
+
+
+template <class ..._Tp> class _LIBCPP_TEMPLATE_VIS tuple;
+
+template <class... _Tp> struct __tuple_like<tuple<_Tp...> > : true_type {};
+
+template <class ..._Tp>
+class _LIBCPP_TEMPLATE_VIS tuple_size<tuple<_Tp...> >
+    : public integral_constant<size_t, sizeof...(_Tp)>
+{
+};
+
+template <size_t _Ip, class ..._Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename tuple_element<_Ip, tuple<_Tp...> >::type&
+get(tuple<_Tp...>&) _NOEXCEPT;
+
+template <size_t _Ip, class ..._Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const typename tuple_element<_Ip, tuple<_Tp...> >::type&
+get(const tuple<_Tp...>&) _NOEXCEPT;
+
+template <size_t _Ip, class ..._Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename tuple_element<_Ip, tuple<_Tp...> >::type&&
+get(tuple<_Tp...>&&) _NOEXCEPT;
+
+template <size_t _Ip, class ..._Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const typename tuple_element<_Ip, tuple<_Tp...> >::type&&
+get(const tuple<_Tp...>&&) _NOEXCEPT;
+
+#endif // !defined(_LIBCPP_CXX03_LANG)
+
+// pair specializations
+
+template <class _T1, class _T2> struct __tuple_like<pair<_T1, _T2> > : true_type {};
+
+template <size_t _Ip, class _T1, class _T2>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename tuple_element<_Ip, pair<_T1, _T2> >::type&
+get(pair<_T1, _T2>&) _NOEXCEPT;
+
+template <size_t _Ip, class _T1, class _T2>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const typename tuple_element<_Ip, pair<_T1, _T2> >::type&
+get(const pair<_T1, _T2>&) _NOEXCEPT;
+
+#ifndef _LIBCPP_CXX03_LANG
+template <size_t _Ip, class _T1, class _T2>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
+get(pair<_T1, _T2>&&) _NOEXCEPT;
+
+template <size_t _Ip, class _T1, class _T2>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
+get(const pair<_T1, _T2>&&) _NOEXCEPT;
+#endif
+
+// array specializations
+
+template <class _Tp, size_t _Size> struct _LIBCPP_TEMPLATE_VIS array;
+
+template <class _Tp, size_t _Size> struct __tuple_like<array<_Tp, _Size> > : true_type {};
+
+template <size_t _Ip, class _Tp, size_t _Size>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp&
+get(array<_Tp, _Size>&) _NOEXCEPT;
+
+template <size_t _Ip, class _Tp, size_t _Size>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const _Tp&
+get(const array<_Tp, _Size>&) _NOEXCEPT;
+
+#ifndef _LIBCPP_CXX03_LANG
+template <size_t _Ip, class _Tp, size_t _Size>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp&&
+get(array<_Tp, _Size>&&) _NOEXCEPT;
+
+template <size_t _Ip, class _Tp, size_t _Size>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const _Tp&&
+get(const array<_Tp, _Size>&&) _NOEXCEPT;
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+
+// __tuple_types
+
+template <class ..._Tp> struct __tuple_types {};
+
+#if !__has_builtin(__type_pack_element)
+
+namespace __indexer_detail {
+
+template <size_t _Idx, class _Tp>
+struct __indexed { using type _LIBCPP_NODEBUG = _Tp; };
+
+template <class _Types, class _Indexes> struct __indexer;
+
+template <class ..._Types, size_t ..._Idx>
+struct __indexer<__tuple_types<_Types...>, __tuple_indices<_Idx...>>
+    : __indexed<_Idx, _Types>...
+{};
+
+template <size_t _Idx, class _Tp>
+__indexed<_Idx, _Tp> __at_index(__indexed<_Idx, _Tp> const&);
+
+} // namespace __indexer_detail
+
+#if !defined(__CUDACC__) || !defined(_MSC_VER)
+template <size_t _Idx, class ..._Types>
+using __type_pack_element _LIBCPP_NODEBUG = typename decltype(
+    __indexer_detail::__at_index<_Idx>(
+        __indexer_detail::__indexer<
+            __tuple_types<_Types...>,
+            typename __make_tuple_indices<sizeof...(_Types)>::type
+        >{})
+  )::type;
+
+#else // !defined(__CUDACC__) || !defined(_MSC_VER)
+template <size_t _Idx, class ..._Types>
+struct __y_type_pack_element {
+    using __t1 = typename __make_tuple_indices<sizeof...(_Types)>::type;
+    using __t2 = __indexer_detail::__indexer<__tuple_types<_Types...>, __t1>;
+    using __t3 = decltype(__indexer_detail::__at_index<_Idx>(__t2{}));
+    using __t4 = typename __t3::type;
+};
+
+template <size_t _Idx, class ..._Types>
+using __type_pack_element = typename __y_type_pack_element<_Idx, _Types...>::__t4;
+
+#endif // !defined(__CUDACC__) || !defined(_MSC_VER)
+
+#endif // __has_builtin(__type_pack_element)
+
+template <size_t _Ip, class ..._Types>
+struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, __tuple_types<_Types...>>
+{
+    static_assert(_Ip < sizeof...(_Types), "tuple_element index out of range");
+    typedef _LIBCPP_NODEBUG __type_pack_element<_Ip, _Types...> type;
+};
+
+
+template <class ..._Tp>
+class _LIBCPP_TEMPLATE_VIS tuple_size<__tuple_types<_Tp...> >
+    : public integral_constant<size_t, sizeof...(_Tp)>
+{
+};
+
+template <class... _Tp> struct __tuple_like<__tuple_types<_Tp...> > : true_type {};
+
+template <bool _ApplyLV, bool _ApplyConst, bool _ApplyVolatile>
+struct __apply_cv_mf;
+template <>
+struct __apply_cv_mf<false, false, false> {
+  template <class _Tp> using __apply = _Tp;
+};
+template <>
+struct __apply_cv_mf<false, true, false> {
+  template <class _Tp> using __apply _LIBCPP_NODEBUG = const _Tp;
+};
+template <>
+struct __apply_cv_mf<false, false, true> {
+  template <class _Tp> using __apply _LIBCPP_NODEBUG = volatile _Tp;
+};
+template <>
+struct __apply_cv_mf<false, true, true> {
+  template <class _Tp> using __apply _LIBCPP_NODEBUG = const volatile _Tp;
+};
+template <>
+struct __apply_cv_mf<true, false, false> {
+  template <class _Tp> using __apply _LIBCPP_NODEBUG = _Tp&;
+};
+template <>
+struct __apply_cv_mf<true, true, false> {
+  template <class _Tp> using __apply _LIBCPP_NODEBUG = const _Tp&;
+};
+template <>
+struct __apply_cv_mf<true, false, true> {
+  template <class _Tp> using __apply _LIBCPP_NODEBUG = volatile _Tp&;
+};
+template <>
+struct __apply_cv_mf<true, true, true> {
+  template <class _Tp> using __apply _LIBCPP_NODEBUG = const volatile _Tp&;
+};
+template <class _Tp, class _RawTp = typename remove_reference<_Tp>::type>
+using __apply_cv_t _LIBCPP_NODEBUG = __apply_cv_mf<
+    is_lvalue_reference<_Tp>::value,
+    is_const<_RawTp>::value,
+    is_volatile<_RawTp>::value>;
+
+// __make_tuple_types
+
+// __make_tuple_types<_Tuple<_Types...>, _Ep, _Sp>::type is a
+// __tuple_types<_Types...> using only those _Types in the range [_Sp, _Ep).
+// _Sp defaults to 0 and _Ep defaults to tuple_size<_Tuple>.  If _Tuple is a
+// lvalue_reference type, then __tuple_types<_Types&...> is the result.
+
+#ifdef _LIBCPP_COMPILER_MSVC
+
+template<class _TupleTypes, class _Tp>
+struct __make_tuple_types_append_front;
+
+template<class ..._Types, class _Tp>
+struct __make_tuple_types_append_front<__tuple_types<_Types...>, _Tp> {
+    using type = __tuple_types<_Tp, _Types...>;
+};
+
+template<class _TupleTypes, class _Apply, size_t _Ep, size_t _Sp, class = void>
+struct __make_tuple_types_flat;
+
+template<class _Tuple, class _Apply>
+struct __make_tuple_types_flat<_Tuple, _Apply, 0, 0, void> {
+    using type = __tuple_types<>;
+};
+
+template<template<class...> class _Tuple, class _Tp, class ..._Types, class _Apply, size_t _Ep>
+struct __make_tuple_types_flat<_Tuple<_Tp, _Types...>, _Apply, _Ep, 0, enable_if_t<(_Ep > 0)>> {
+    using type = typename __make_tuple_types_append_front<
+        typename __make_tuple_types_flat<__tuple_types<_Types...>, _Apply, _Ep - 1, 0>::type,
+        typename _Apply::template __apply<_Tp>>::type;
+};
+
+template<template <class...> class _Tuple, class _Tp, class ..._Types, class _Apply, size_t _Ep, size_t _Sp>
+struct __make_tuple_types_flat<_Tuple<_Tp, _Types...>, _Apply, _Ep, _Sp, enable_if_t<(_Ep > 0 && _Sp > 0)>> {
+    using type = typename __make_tuple_types_flat<__tuple_types<_Types...>, _Apply, _Ep - 1, _Sp - 1>::type;
+};
+
+template<class _Tp, size_t _Np, class _Apply, size_t _Ep>
+struct __make_tuple_types_flat<array<_Tp, _Np>, _Apply, _Ep, 0, enable_if_t<(_Ep > 0)>> {
+    using type = typename __make_tuple_types_append_front<
+        typename __make_tuple_types_flat<array<_Tp, _Np>, _Apply, _Ep - 1, 0>::type,
+        typename _Apply::template __apply<_Tp>>::type;
+};
+
+template<class _Tp, size_t _Np, class _Apply, size_t _Ep, size_t _Sp>
+struct __make_tuple_types_flat<array<_Tp, _Np>, _Apply, _Ep, _Sp, enable_if_t<(_Sp > 0)>> {
+    using type = typename __make_tuple_types_flat<array<_Tp, _Np>, _Apply, _Ep - _Sp, 0>::type;
+};
+
+template<class _Tp,
+         size_t _Ep = tuple_size<remove_reference_t<_Tp>>::value,
+         size_t _Sp = 0,
+         bool _SameSize = (_Ep == tuple_size<typename remove_reference<_Tp>::type>::value)>
+struct __make_tuple_types {
+    static_assert(_Sp <= _Ep, "__make_tuple_types input error");
+    using _RawTp = typename remove_cv<typename remove_reference<_Tp>::type>::type;
+    using type = typename __make_tuple_types_flat<_RawTp, __apply_cv_t<_Tp>, _Ep, _Sp>::type;
+};
+
+template <class ..._Types, size_t _Ep>
+struct __make_tuple_types<tuple<_Types...>, _Ep, 0, true> {
+  typedef __tuple_types<_Types...> type;
+};
+
+template <class ..._Types, size_t _Ep>
+struct __make_tuple_types<__tuple_types<_Types...>, _Ep, 0, true> {
+  typedef __tuple_types<_Types...> type;
+};
+
+#else
+
+template <class _TupleTypes, class _TupleIndices>
+struct __make_tuple_types_flat;
+
+template <template <class...> class _Tuple, class ..._Types, size_t ..._Idx>
+struct __make_tuple_types_flat<_Tuple<_Types...>, __tuple_indices<_Idx...>> {
+  // Specialization for pair, tuple, and __tuple_types
+  template <class _Tp, class _ApplyFn = __apply_cv_t<_Tp>>
+  using __apply_quals _LIBCPP_NODEBUG = __tuple_types<
+      typename _ApplyFn::template __apply<__type_pack_element<_Idx, _Types...>>...
+    >;
+};
+
+template <class _Vt, size_t _Np, size_t ..._Idx>
+struct __make_tuple_types_flat<array<_Vt, _Np>, __tuple_indices<_Idx...>> {
+  template <size_t>
+  using __value_type = _Vt;
+  template <class _Tp, class _ApplyFn = __apply_cv_t<_Tp>>
+  using __apply_quals = __tuple_types<
+      typename _ApplyFn::template __apply<__value_type<_Idx>>...
+    >;
+};
+
+template <class _Tp, size_t _Ep = tuple_size<typename remove_reference<_Tp>::type>::value,
+          size_t _Sp = 0,
+          bool _SameSize = (_Ep == tuple_size<typename remove_reference<_Tp>::type>::value)>
+struct __make_tuple_types
+{
+    static_assert(_Sp <= _Ep, "__make_tuple_types input error");
+    using _RawTp = typename remove_cv<typename remove_reference<_Tp>::type>::type;
+    using _Maker = __make_tuple_types_flat<_RawTp, typename __make_tuple_indices<_Ep, _Sp>::type>;
+    using type = typename _Maker::template __apply_quals<_Tp>;
+};
+
+template <class ..._Types, size_t _Ep>
+struct __make_tuple_types<tuple<_Types...>, _Ep, 0, true> {
+  typedef _LIBCPP_NODEBUG __tuple_types<_Types...> type;
+};
+
+template <class ..._Types, size_t _Ep>
+struct __make_tuple_types<__tuple_types<_Types...>, _Ep, 0, true> {
+  typedef _LIBCPP_NODEBUG __tuple_types<_Types...> type;
+};
+
+#endif // _LIBCPP_COMPILER_MSVC
+
+template <bool ..._Preds>
+struct __all_dummy;
+
+template <bool ..._Pred>
+using __all = _IsSame<__all_dummy<_Pred...>, __all_dummy<(_Pred | true)...>>;
+
+struct __tuple_sfinae_base {
+  template <template <class, class...> class _Trait,
+            class ..._LArgs, class ..._RArgs>
+  static auto __do_test(__tuple_types<_LArgs...>, __tuple_types<_RArgs...>)
+    -> __all<_Trait<_LArgs, _RArgs>::value...>;
+  template <template <class...> class>
+  static auto __do_test(...) -> false_type;
+
+  template <class _FromArgs, class _ToArgs>
+  using __constructible = decltype(__do_test<is_constructible>(declval<_ToArgs>(), declval<_FromArgs>()));
+  template <class _FromArgs, class _ToArgs>
+  using __convertible = decltype(__do_test<is_convertible>(declval<_FromArgs>(), declval<_ToArgs>()));
+  template <class _FromArgs, class _ToArgs>
+  using __assignable = decltype(__do_test<is_assignable>(declval<_ToArgs>(), declval<_FromArgs>()));
+};
+
+// __tuple_convertible
+
+template <class _Tp, class _Up, bool = __tuple_like<typename remove_reference<_Tp>::type>::value,
+                                bool = __tuple_like<_Up>::value,
+                                class = void>
+struct __tuple_convertible
+    : public false_type {};
+
+template <class _Tp, class _Up>
+struct __tuple_convertible<_Tp, _Up, true, true,
+                           typename enable_if<(tuple_size<typename remove_reference<_Tp>::type>::value == tuple_size<_Up>::value)>::type>
+    : public __tuple_sfinae_base::__convertible<
+      typename __make_tuple_types<_Tp>::type
+    , typename __make_tuple_types<_Up>::type
+    >
+{};
+
+// __tuple_constructible
+
+template <class _Tp, class _Up, bool = __tuple_like<typename remove_reference<_Tp>::type>::value,
+                                bool = __tuple_like<_Up>::value,
+                                class = void>
+struct __tuple_constructible
+    : public false_type {};
+
+template <class _Tp, class _Up>
+struct __tuple_constructible<_Tp, _Up, true, true,
+                             typename enable_if<(tuple_size<typename remove_reference<_Tp>::type>::value == tuple_size<_Up>::value)>::type>
+    : public __tuple_sfinae_base::__constructible<
+      typename __make_tuple_types<_Tp>::type
+    , typename __make_tuple_types<_Up>::type
+    >
+{};
+
+// __tuple_assignable
+
+template <class _Tp, class _Up, bool = __tuple_like<typename remove_reference<_Tp>::type>::value,
+                                bool = __tuple_like<_Up>::value,
+                                class = void>
+struct __tuple_assignable
+    : public false_type {};
+
+template <class _Tp, class _Up>
+struct __tuple_assignable<_Tp, _Up, true, true,
+                          typename enable_if<(tuple_size<typename remove_reference<_Tp>::type>::value == tuple_size<_Up>::value)>::type>
+    : public __tuple_sfinae_base::__assignable<
+      typename __make_tuple_types<_Tp>::type
+    , typename __make_tuple_types<_Up&>::type
+    >
+{};
+
+
+template <size_t _Ip, class ..._Tp>
+struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, tuple<_Tp...> >
+{
+    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, __tuple_types<_Tp...> >::type type;
+};
+
+#if _LIBCPP_STD_VER > 11
+template <size_t _Ip, class ..._Tp>
+using tuple_element_t _LIBCPP_NODEBUG = typename tuple_element <_Ip, _Tp...>::type;
+#endif
+
+template <bool _IsTuple, class _SizeTrait, size_t _Expected>
+struct __tuple_like_with_size_imp : false_type {};
+
+template <class _SizeTrait, size_t _Expected>
+struct __tuple_like_with_size_imp<true, _SizeTrait, _Expected>
+    : integral_constant<bool, _SizeTrait::value == _Expected> {};
+
+template <class _Tuple, size_t _ExpectedSize,
+          class _RawTuple = typename __uncvref<_Tuple>::type>
+using __tuple_like_with_size _LIBCPP_NODEBUG = __tuple_like_with_size_imp<
+                                   __tuple_like<_RawTuple>::value,
+                                   tuple_size<_RawTuple>, _ExpectedSize
+                              >;
+
+struct _LIBCPP_TYPE_VIS __check_tuple_constructor_fail {
+
+    static constexpr bool __enable_explicit_default() { return false; }
+    static constexpr bool __enable_implicit_default() { return false; }
+    template <class ...>
+    static constexpr bool __enable_explicit() { return false; }
+    template <class ...>
+    static constexpr bool __enable_implicit() { return false; }
+    template <class ...>
+    static constexpr bool __enable_assign() { return false; }
+};
+#endif // !defined(_LIBCPP_CXX03_LANG)
+
+#if _LIBCPP_STD_VER > 14
+
+template <bool _CanCopy, bool _CanMove>
+struct __sfinae_ctor_base {};
+template <>
+struct __sfinae_ctor_base<false, false> {
+  __sfinae_ctor_base() = default;
+  __sfinae_ctor_base(__sfinae_ctor_base const&) = delete;
+  __sfinae_ctor_base(__sfinae_ctor_base &&) = delete;
+  __sfinae_ctor_base& operator=(__sfinae_ctor_base const&) = default;
+  __sfinae_ctor_base& operator=(__sfinae_ctor_base&&) = default;
+};
+template <>
+struct __sfinae_ctor_base<true, false> {
+  __sfinae_ctor_base() = default;
+  __sfinae_ctor_base(__sfinae_ctor_base const&) = default;
+  __sfinae_ctor_base(__sfinae_ctor_base &&) = delete;
+  __sfinae_ctor_base& operator=(__sfinae_ctor_base const&) = default;
+  __sfinae_ctor_base& operator=(__sfinae_ctor_base&&) = default;
+};
+template <>
+struct __sfinae_ctor_base<false, true> {
+  __sfinae_ctor_base() = default;
+  __sfinae_ctor_base(__sfinae_ctor_base const&) = delete;
+  __sfinae_ctor_base(__sfinae_ctor_base &&) = default;
+  __sfinae_ctor_base& operator=(__sfinae_ctor_base const&) = default;
+  __sfinae_ctor_base& operator=(__sfinae_ctor_base&&) = default;
+};
+
+template <bool _CanCopy, bool _CanMove>
+struct __sfinae_assign_base {};
+template <>
+struct __sfinae_assign_base<false, false> {
+  __sfinae_assign_base() = default;
+  __sfinae_assign_base(__sfinae_assign_base const&) = default;
+  __sfinae_assign_base(__sfinae_assign_base &&) = default;
+  __sfinae_assign_base& operator=(__sfinae_assign_base const&) = delete;
+  __sfinae_assign_base& operator=(__sfinae_assign_base&&) = delete;
+};
+template <>
+struct __sfinae_assign_base<true, false> {
+  __sfinae_assign_base() = default;
+  __sfinae_assign_base(__sfinae_assign_base const&) = default;
+  __sfinae_assign_base(__sfinae_assign_base &&) = default;
+  __sfinae_assign_base& operator=(__sfinae_assign_base const&) = default;
+  __sfinae_assign_base& operator=(__sfinae_assign_base&&) = delete;
+};
+template <>
+struct __sfinae_assign_base<false, true> {
+  __sfinae_assign_base() = default;
+  __sfinae_assign_base(__sfinae_assign_base const&) = default;
+  __sfinae_assign_base(__sfinae_assign_base &&) = default;
+  __sfinae_assign_base& operator=(__sfinae_assign_base const&) = delete;
+  __sfinae_assign_base& operator=(__sfinae_assign_base&&) = default;
+};
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___TUPLE
diff --git a/contrib/libs/cxxsupp/libcxx/include/__undef_macros b/contrib/libs/cxxsupp/libcxx/include/__undef_macros
new file mode 100644
index 00000000000..4923ee6b4a1
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__undef_macros
@@ -0,0 +1,33 @@
+// -*- C++ -*-
+//===------------------------ __undef_macros ------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+
+#ifdef min
+#if !defined(_LIBCPP_DISABLE_MACRO_CONFLICT_WARNINGS)
+#if defined(_LIBCPP_WARNING)
+_LIBCPP_WARNING("macro min is incompatible with C++.  Try #define NOMINMAX "
+                "before any Windows header. #undefing min")
+#else
+#warning: macro min is incompatible with C++.  #undefing min
+#endif
+#endif
+#undef min
+#endif
+
+#ifdef max
+#if !defined(_LIBCPP_DISABLE_MACRO_CONFLICT_WARNINGS)
+#if defined(_LIBCPP_WARNING)
+_LIBCPP_WARNING("macro max is incompatible with C++.  Try #define NOMINMAX "
+                "before any Windows header. #undefing max")
+#else
+#warning: macro max is incompatible with C++.  #undefing max
+#endif
+#endif
+#undef max
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/as_const.h b/contrib/libs/cxxsupp/libcxx/include/__utility/as_const.h
new file mode 100644
index 00000000000..52da739875e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/as_const.h
@@ -0,0 +1,33 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_AS_CONST_H
+#define _LIBCPP___UTILITY_AS_CONST_H
+
+#include <__config>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+_LIBCPP_NODISCARD_EXT constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
+
+template <class _Tp>
+void as_const(const _Tp&&) = delete;
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_AS_CONST_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/cmp.h b/contrib/libs/cxxsupp/libcxx/include/__utility/cmp.h
new file mode 100644
index 00000000000..4fc96b054f4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/cmp.h
@@ -0,0 +1,110 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_CMP_H
+#define _LIBCPP___UTILITY_CMP_H
+
+#include <__config>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <limits>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+template<class _Tp, class... _Up>
+struct _IsSameAsAny : _Or<_IsSame<_Tp, _Up>...> {};
+
+template<class _Tp>
+concept __is_safe_integral_cmp = is_integral_v<_Tp> &&
+                      !_IsSameAsAny<_Tp, bool, char
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+                                    , char8_t
+#endif
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+                                    , char16_t, char32_t
+#endif
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+                                    , wchar_t
+#endif
+                                    >::value;
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool cmp_equal(_Tp __t, _Up __u) noexcept
+{
+  if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
+    return __t == __u;
+  else if constexpr (is_signed_v<_Tp>)
+    return __t < 0 ? false : make_unsigned_t<_Tp>(__t) == __u;
+  else
+    return __u < 0 ? false : __t == make_unsigned_t<_Up>(__u);
+}
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool cmp_not_equal(_Tp __t, _Up __u) noexcept
+{
+  return !_VSTD::cmp_equal(__t, __u);
+}
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool cmp_less(_Tp __t, _Up __u) noexcept
+{
+  if constexpr (is_signed_v<_Tp> == is_signed_v<_Up>)
+    return __t < __u;
+  else if constexpr (is_signed_v<_Tp>)
+    return __t < 0 ? true : make_unsigned_t<_Tp>(__t) < __u;
+  else
+    return __u < 0 ? false : __t < make_unsigned_t<_Up>(__u);
+}
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool cmp_greater(_Tp __t, _Up __u) noexcept
+{
+  return _VSTD::cmp_less(__u, __t);
+}
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool cmp_less_equal(_Tp __t, _Up __u) noexcept
+{
+  return !_VSTD::cmp_greater(__t, __u);
+}
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool cmp_greater_equal(_Tp __t, _Up __u) noexcept
+{
+  return !_VSTD::cmp_less(__t, __u);
+}
+
+template<__is_safe_integral_cmp _Tp, __is_safe_integral_cmp _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool in_range(_Up __u) noexcept
+{
+  return _VSTD::cmp_less_equal(__u, numeric_limits<_Tp>::max()) &&
+         _VSTD::cmp_greater_equal(__u, numeric_limits<_Tp>::min());
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___UTILITY_CMP_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/decay_copy.h b/contrib/libs/cxxsupp/libcxx/include/__utility/decay_copy.h
new file mode 100644
index 00000000000..1a7b399d917
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/decay_copy.h
@@ -0,0 +1,34 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_DECAY_COPY_H
+#define _LIBCPP___UTILITY_DECAY_COPY_H
+
+#include <__config>
+#include <__utility/forward.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY typename decay<_Tp>::type __decay_copy(_Tp&& __t)
+#if _LIBCPP_STD_VER > 17
+    noexcept(is_nothrow_convertible_v<_Tp, remove_reference_t<_Tp> >)
+#endif
+{
+  return _VSTD::forward<_Tp>(__t);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_DECAY_COPY_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/declval.h b/contrib/libs/cxxsupp/libcxx/include/__utility/declval.h
new file mode 100644
index 00000000000..873b0c3246c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/declval.h
@@ -0,0 +1,53 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_DECLVAL_H
+#define _LIBCPP___UTILITY_DECLVAL_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Suppress deprecation notice for volatile-qualified return type resulting
+// from volatile-qualified types _Tp.
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <class _Tp>
+_Tp&& __declval(int);
+template <class _Tp>
+_Tp __declval(long);
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template <class _Tp>
+using __declval_void = void;
+
+template <class _Tp, class = void>
+struct __declval_add_rvalue_reference {
+    using type = _Tp;
+};
+template <class _Tp>
+struct __declval_add_rvalue_reference<_Tp, __declval_void<_Tp&>> {
+    using type = _Tp&&;
+};
+#endif
+
+template <class _Tp>
+#ifdef _LIBCPP_COMPILER_MSVC
+typename __declval_add_rvalue_reference<_Tp>::type
+#else
+decltype(__declval<_Tp>(0))
+#endif
+declval() _NOEXCEPT;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_DECLVAL_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/exchange.h b/contrib/libs/cxxsupp/libcxx/include/__utility/exchange.h
new file mode 100644
index 00000000000..f9c92c622f5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/exchange.h
@@ -0,0 +1,37 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_EXCHANGE_H
+#define _LIBCPP___UTILITY_EXCHANGE_H
+
+#include <__config>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 11
+template<class _T1, class _T2 = _T1>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_T1 exchange(_T1& __obj, _T2&& __new_value)
+    noexcept(is_nothrow_move_constructible<_T1>::value && is_nothrow_assignable<_T1&, _T2>::value)
+{
+    _T1 __old_value = _VSTD::move(__obj);
+    __obj = _VSTD::forward<_T2>(__new_value);
+    return __old_value;
+}
+#endif // _LIBCPP_STD_VER > 11
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_EXCHANGE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/forward.h b/contrib/libs/cxxsupp/libcxx/include/__utility/forward.h
new file mode 100644
index 00000000000..7629a87d74f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/forward.h
@@ -0,0 +1,37 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_FORWARD_H
+#define _LIBCPP___UTILITY_FORWARD_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR _Tp&&
+forward(typename remove_reference<_Tp>::type& __t) _NOEXCEPT {
+  return static_cast<_Tp&&>(__t);
+}
+
+template <class _Tp>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR _Tp&&
+forward(typename remove_reference<_Tp>::type&& __t) _NOEXCEPT {
+  static_assert(!is_lvalue_reference<_Tp>::value, "cannot forward an rvalue as an lvalue");
+  return static_cast<_Tp&&>(__t);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_FORWARD_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/in_place.h b/contrib/libs/cxxsupp/libcxx/include/__utility/in_place.h
new file mode 100644
index 00000000000..846b4a6d4df
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/in_place.h
@@ -0,0 +1,58 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_IN_PLACE_H
+#define _LIBCPP___UTILITY_IN_PLACE_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+struct _LIBCPP_TYPE_VIS in_place_t {
+    explicit in_place_t() = default;
+};
+inline constexpr in_place_t in_place{};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS in_place_type_t {
+    explicit in_place_type_t() = default;
+};
+template <class _Tp>
+inline constexpr in_place_type_t<_Tp> in_place_type{};
+
+template <size_t _Idx>
+struct _LIBCPP_TEMPLATE_VIS in_place_index_t {
+    explicit in_place_index_t() = default;
+};
+template <size_t _Idx>
+inline constexpr in_place_index_t<_Idx> in_place_index{};
+
+template <class _Tp> struct __is_inplace_type_imp : false_type {};
+template <class _Tp> struct __is_inplace_type_imp<in_place_type_t<_Tp>> : true_type {};
+
+template <class _Tp>
+using __is_inplace_type = __is_inplace_type_imp<__uncvref_t<_Tp>>;
+
+template <class _Tp> struct __is_inplace_index_imp : false_type {};
+template <size_t _Idx> struct __is_inplace_index_imp<in_place_index_t<_Idx>> : true_type {};
+
+template <class _Tp>
+using __is_inplace_index = __is_inplace_index_imp<__uncvref_t<_Tp>>;
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_IN_PLACE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/integer_sequence.h b/contrib/libs/cxxsupp/libcxx/include/__utility/integer_sequence.h
new file mode 100644
index 00000000000..141f230763a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/integer_sequence.h
@@ -0,0 +1,94 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
+#define _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 11
+
+template<class _Tp, _Tp... _Ip>
+struct _LIBCPP_TEMPLATE_VIS integer_sequence
+{
+    typedef _Tp value_type;
+    static_assert( is_integral<_Tp>::value,
+                  "std::integer_sequence can only be instantiated with an integral type" );
+    static
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr
+    size_t
+    size() noexcept { return sizeof...(_Ip); }
+};
+
+template<size_t... _Ip>
+    using index_sequence = integer_sequence<size_t, _Ip...>;
+
+#if __has_builtin(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
+
+template <class _Tp, _Tp _Ep>
+using __make_integer_sequence _LIBCPP_NODEBUG = __make_integer_seq<integer_sequence, _Tp, _Ep>;
+
+#else
+
+template <class _Tp, class _T> struct __integer_sequence_convert {
+    using type = integer_sequence<_Tp>;
+};
+
+template<class _Tp, class _Tp2, _Tp... _Values>
+struct __integer_sequence_convert<_Tp, __integer_sequence<_Tp2, _Values...>> {
+    using type = integer_sequence<_Tp, _Values...>;
+};
+
+template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked _LIBCPP_NODEBUG =
+  typename __integer_sequence_convert<_Tp, typename __detail::__make<_Np>::type>::type;
+
+template <class _Tp, _Tp _Ep>
+struct __make_integer_sequence_checked
+{
+    static_assert(is_integral<_Tp>::value,
+                  "std::make_integer_sequence can only be instantiated with an integral type" );
+    static_assert(0 <= _Ep, "std::make_integer_sequence must have a non-negative sequence length");
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4296 )
+#endif
+    // Workaround GCC bug by preventing bad installations when 0 <= _Ep
+    // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68929
+    typedef _LIBCPP_NODEBUG __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type;
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+};
+
+template <class _Tp, _Tp _Ep>
+using __make_integer_sequence _LIBCPP_NODEBUG = typename __make_integer_sequence_checked<_Tp, _Ep>::type;
+
+#endif
+
+template<class _Tp, _Tp _Np>
+    using make_integer_sequence = __make_integer_sequence<_Tp, _Np>;
+
+template<size_t _Np>
+    using make_index_sequence = make_integer_sequence<size_t, _Np>;
+
+template<class... _Tp>
+    using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
+
+#endif // _LIBCPP_STD_VER > 11
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_INTEGER_SEQUENCE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/move.h b/contrib/libs/cxxsupp/libcxx/include/__utility/move.h
new file mode 100644
index 00000000000..75d715dc66d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/move.h
@@ -0,0 +1,47 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_MOVE_H
+#define _LIBCPP___UTILITY_MOVE_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR typename remove_reference<_Tp>::type&&
+move(_Tp&& __t) _NOEXCEPT {
+  typedef _LIBCPP_NODEBUG typename remove_reference<_Tp>::type _Up;
+  return static_cast<_Up&&>(__t);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp>
+using __move_if_noexcept_result_t =
+    typename conditional<!is_nothrow_move_constructible<_Tp>::value && is_copy_constructible<_Tp>::value, const _Tp&,
+                         _Tp&&>::type;
+#else // _LIBCPP_CXX03_LANG
+template <class _Tp>
+using __move_if_noexcept_result_t = const _Tp&;
+#endif
+
+template <class _Tp>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 __move_if_noexcept_result_t<_Tp>
+move_if_noexcept(_Tp& __x) _NOEXCEPT {
+  return _VSTD::move(__x);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_MOVE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/pair.h b/contrib/libs/cxxsupp/libcxx/include/__utility/pair.h
new file mode 100644
index 00000000000..3a1ba8ab7c7
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/pair.h
@@ -0,0 +1,619 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_PAIR_H
+#define _LIBCPP___UTILITY_PAIR_H
+
+#include <__compare/common_comparison_category.h>
+#include <__compare/synth_three_way.h>
+#include <__config>
+#include <__functional/unwrap_ref.h>
+#include <__tuple>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <__utility/piecewise_construct.h>
+#include <cstddef>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
+template <class, class>
+struct __non_trivially_copyable_base {
+  _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+  __non_trivially_copyable_base() _NOEXCEPT {}
+  _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+  __non_trivially_copyable_base(__non_trivially_copyable_base const&) _NOEXCEPT {}
+};
+#endif
+
+template <class _T1, class _T2>
+struct _LIBCPP_TEMPLATE_VIS pair
+#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
+: private __non_trivially_copyable_base<_T1, _T2>
+#endif
+{
+    typedef _T1 first_type;
+    typedef _T2 second_type;
+
+    _T1 first;
+    _T2 second;
+
+#if !defined(_LIBCPP_CXX03_LANG)
+    pair(pair const&) = default;
+    pair(pair&&) = default;
+#else
+  // Use the implicitly declared copy constructor in C++03
+#endif
+
+#ifdef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    pair() : first(), second() {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair(_T1 const& __t1, _T2 const& __t2) : first(__t1), second(__t2) {}
+
+    template <class _U1, class _U2>
+    _LIBCPP_INLINE_VISIBILITY
+    pair(const pair<_U1, _U2>& __p) : first(__p.first), second(__p.second) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair& operator=(pair const& __p) {
+        first = __p.first;
+        second = __p.second;
+        return *this;
+    }
+#else
+    template<bool _Dummy = true, int&... _Args>
+    struct _EnableImplicitDefaultConstructor {
+        static constexpr bool value = __is_implicitly_default_constructible<_T1>::value
+            && __is_implicitly_default_constructible<_T2>::value;
+    };
+
+    template<bool _Dummy = true, int&... _Args>
+    struct _EnableExplicitDefaultConstructor {
+        static constexpr bool value = is_default_constructible<_T1>::value
+            && is_default_constructible<_T2>::value
+            && !_EnableImplicitDefaultConstructor<_Dummy, _Args...>::value;
+    };
+
+    template <class _U1, class _U2, bool _Dummy = true>
+    struct _EnableExplicitConstructor {
+        static constexpr bool value = is_constructible<first_type, _U1>::value
+            && is_constructible<second_type, _U2>::value
+            && (!is_convertible<_U1, first_type>::value
+            || !is_convertible<_U2, second_type>::value);
+    };
+
+    template <class _U1, class _U2, bool _Dummy = true>
+    struct _EnableImplicitConstructor {
+        static constexpr bool value = is_constructible<first_type, _U1>::value
+            && is_constructible<second_type, _U2>::value
+            && is_convertible<_U1, first_type>::value
+            && is_convertible<_U2, second_type>::value;
+    };
+
+    template <class _Tuple, bool _Enable = __tuple_like_with_size<_Tuple, 2>::value
+        && !is_same<typename decay<_Tuple>::type, pair>::value>
+    struct _EnableImplicitTupleLikeConstructor {
+        static constexpr bool value = false;
+    };
+
+    template <class _Tuple, bool _Enable = __tuple_like_with_size<_Tuple, 2>::value
+        && !is_same<typename decay<_Tuple>::type, pair>::value>
+    struct _EnableExplicitTupleLikeConstructor {
+        static constexpr bool value = false;
+    };
+
+    template <class _Tuple, bool _Enable = __tuple_like_with_size<_Tuple, 2>::value
+        && !is_same<typename decay<_Tuple>::type, pair>::value>
+    struct _EnableTupleLikeAssign {
+        static constexpr bool value = false;
+    };
+
+    template <class _Tuple>
+    struct _EnableImplicitTupleLikeConstructor<_Tuple, true> {
+        static constexpr bool value = __tuple_convertible<_Tuple, pair>::value;
+    };
+
+    template <class _Tuple>
+    struct _EnableExplicitTupleLikeConstructor<_Tuple, true> {
+        static constexpr bool value = __tuple_constructible<_Tuple, pair>::value
+            && !__tuple_convertible<_Tuple, pair>::value;
+    };
+
+    template <class _Tuple>
+    struct _EnableTupleLikeAssign<_Tuple, true> {
+        static constexpr bool value = __tuple_assignable<_Tuple, pair>::value;
+    };
+
+    template<bool _Dummy = true, typename enable_if<
+            _EnableExplicitDefaultConstructor<_Dummy>::value
+    >::type* = nullptr>
+    explicit _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    pair()
+// danlark@ if you remove this define, MSVC gets into ICE
+#if !defined(_LIBCPP_COMPILER_MSVC)
+    _NOEXCEPT_(is_nothrow_default_constructible<first_type>::value &&
+               is_nothrow_default_constructible<second_type>::value)
+#endif
+        : first(), second() {}
+
+    template<bool _Dummy = true, typename enable_if<
+             _EnableImplicitDefaultConstructor<_Dummy>::value
+    >::type* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    pair()
+// danlark@ if you remove this define, MSVC gets into ICE
+#if !defined(_LIBCPP_COMPILER_MSVC)
+    _NOEXCEPT_(is_nothrow_default_constructible<first_type>::value &&
+               is_nothrow_default_constructible<second_type>::value)
+#endif
+        : first(), second() {}
+
+    template <bool _Dummy = true, typename enable_if<
+             _EnableExplicitConstructor<_T1 const&, _T2 const&, _Dummy>::value
+    >::type* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit pair(_T1 const& __t1, _T2 const& __t2)
+        _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
+                   is_nothrow_copy_constructible<second_type>::value)
+        : first(__t1), second(__t2) {}
+
+    template<bool _Dummy = true, bool _Dummy2 = true, typename enable_if<
+            _EnableImplicitConstructor<_T1 const&, _T2 const&, _Dummy>::value
+    >::type* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    pair(_T1 const& __t1, _T2 const& __t2)
+        _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
+                   is_nothrow_copy_constructible<second_type>::value)
+        : first(__t1), second(__t2) {}
+
+    template <
+#if _LIBCPP_STD_VER > 20 // http://wg21.link/P1951
+        class _U1 = _T1, class _U2 = _T2,
+#else
+        class _U1, class _U2,
+#endif
+        typename enable_if<_EnableExplicitConstructor<_U1, _U2>::value>::type* = nullptr
+    >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit pair(_U1&& __u1, _U2&& __u2)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1>::value &&
+                    is_nothrow_constructible<second_type, _U2>::value))
+        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
+
+    template<
+#if _LIBCPP_STD_VER > 20 // http://wg21.link/P1951
+        class _U1 = _T1, class _U2 = _T2,
+#else
+        class _U1, class _U2,
+#endif
+        bool _Dummy = true, typename enable_if<_EnableImplicitConstructor<_U1, _U2, _Dummy>::value>::type* = nullptr
+    >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    pair(_U1&& __u1, _U2&& __u2)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1>::value &&
+                    is_nothrow_constructible<second_type, _U2>::value))
+        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
+
+    template<class _U1, class _U2, typename enable_if<
+            _EnableExplicitConstructor<_U1 const&, _U2 const&>::value
+    >::type* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit pair(pair<_U1, _U2> const& __p)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1 const&>::value &&
+                    is_nothrow_constructible<second_type, _U2 const&>::value))
+        : first(__p.first), second(__p.second) {}
+
+    template<class _U1, class _U2, bool _Dummy = true, typename enable_if<
+            _EnableImplicitConstructor<_U1 const&, _U2 const&, _Dummy>::value
+    >::type* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    pair(pair<_U1, _U2> const& __p)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1 const&>::value &&
+                    is_nothrow_constructible<second_type, _U2 const&>::value))
+        : first(__p.first), second(__p.second) {}
+
+    template<class _U1, class _U2, typename enable_if<
+            _EnableExplicitConstructor<_U1, _U2>::value
+    >::type* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit pair(pair<_U1, _U2>&&__p)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1&&>::value &&
+                    is_nothrow_constructible<second_type, _U2&&>::value))
+        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
+
+    template<class _U1, class _U2, bool _Dummy = true, typename enable_if<
+            _EnableImplicitConstructor<_U1, _U2>::value
+    >::type* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    pair(pair<_U1, _U2>&& __p)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1&&>::value &&
+                    is_nothrow_constructible<second_type, _U2&&>::value))
+        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
+
+    template<class _Tuple, typename enable_if<
+            _EnableExplicitTupleLikeConstructor<_Tuple>::value
+    >::type* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit pair(_Tuple&& __p)
+        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
+          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
+
+    template<class _Tuple, bool _Dummy = true, typename enable_if<
+            _EnableImplicitTupleLikeConstructor<_Tuple>::value
+    >::type* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    pair(_Tuple&& __p)
+        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
+          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
+
+    template <class... _Args1, class... _Args2>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    pair(piecewise_construct_t __pc,
+         tuple<_Args1...> __first_args, tuple<_Args2...> __second_args)
+        _NOEXCEPT_((is_nothrow_constructible<first_type, _Args1...>::value &&
+                    is_nothrow_constructible<second_type, _Args2...>::value))
+        : pair(__pc, __first_args, __second_args,
+                typename __make_tuple_indices<sizeof...(_Args1)>::type(),
+                typename __make_tuple_indices<sizeof...(_Args2) >::type()) {}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    pair& operator=(typename conditional<
+                        is_copy_assignable<first_type>::value &&
+                        is_copy_assignable<second_type>::value,
+                    pair, __nat>::type const& __p)
+        _NOEXCEPT_(is_nothrow_copy_assignable<first_type>::value &&
+                   is_nothrow_copy_assignable<second_type>::value)
+    {
+        first = __p.first;
+        second = __p.second;
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    pair& operator=(typename conditional<
+                        is_move_assignable<first_type>::value &&
+                        is_move_assignable<second_type>::value,
+                    pair, __nat>::type&& __p)
+        _NOEXCEPT_(is_nothrow_move_assignable<first_type>::value &&
+                   is_nothrow_move_assignable<second_type>::value)
+    {
+        first = _VSTD::forward<first_type>(__p.first);
+        second = _VSTD::forward<second_type>(__p.second);
+        return *this;
+    }
+
+    template <class _Tuple, bool _Dummy = true, typename enable_if<
+            _EnableTupleLikeAssign<_Tuple>::value
+     >::type* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    pair& operator=(_Tuple&& __p) {
+        first = _VSTD::get<0>(_VSTD::forward<_Tuple>(__p));
+        second = _VSTD::get<1>(_VSTD::forward<_Tuple>(__p));
+        return *this;
+    }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    void
+    swap(pair& __p) _NOEXCEPT_(__is_nothrow_swappable<first_type>::value &&
+                               __is_nothrow_swappable<second_type>::value)
+    {
+        using _VSTD::swap;
+        swap(first,  __p.first);
+        swap(second, __p.second);
+    }
+private:
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class... _Args1, class... _Args2, size_t... _I1, size_t... _I2>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+        pair(piecewise_construct_t,
+             tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
+             __tuple_indices<_I1...>, __tuple_indices<_I2...>);
+#endif
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _T1, class _T2>
+pair(_T1, _T2) -> pair<_T1, _T2>;
+#endif
+
+// [pairs.spec], specialized algorithms
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator==(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
+{
+    return __x.first == __y.first && __x.second == __y.second;
+}
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR) && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+template <class _T1, class _T2>
+_LIBCPP_HIDE_FROM_ABI constexpr
+common_comparison_category_t<
+        __synth_three_way_result<_T1>,
+        __synth_three_way_result<_T2> >
+operator<=>(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
+{
+    if (auto __c = _VSTD::__synth_three_way(__x.first, __y.first); __c != 0) {
+      return __c;
+    }
+    return _VSTD::__synth_three_way(__x.second, __y.second);
+}
+
+#else // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR) && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator!=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator< (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
+{
+    return __x.first < __y.first || (!(__y.first < __x.first) && __x.second < __y.second);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator> (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
+{
+    return __y < __x;
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator>=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator<=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
+{
+    return !(__y < __x);
+}
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR) && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+typename enable_if
+<
+    __is_swappable<_T1>::value &&
+    __is_swappable<_T2>::value,
+    void
+>::type
+swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
+                     _NOEXCEPT_((__is_nothrow_swappable<_T1>::value &&
+                                 __is_nothrow_swappable<_T2>::value))
+{
+    __x.swap(__y);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
+make_pair(_T1&& __t1, _T2&& __t2)
+{
+    return pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
+               (_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
+}
+
+#else  // _LIBCPP_CXX03_LANG
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+pair<_T1,_T2>
+make_pair(_T1 __x, _T2 __y)
+{
+    return pair<_T1, _T2>(__x, __y);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _T1, class _T2>
+  struct _LIBCPP_TEMPLATE_VIS tuple_size<pair<_T1, _T2> >
+    : public integral_constant<size_t, 2> {};
+
+template <size_t _Ip, class _T1, class _T2>
+struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, pair<_T1, _T2> >
+{
+    static_assert(_Ip < 2, "Index out of bounds in std::tuple_element<std::pair<T1, T2>>");
+};
+
+template <class _T1, class _T2>
+struct _LIBCPP_TEMPLATE_VIS tuple_element<0, pair<_T1, _T2> >
+{
+    typedef _LIBCPP_NODEBUG _T1 type;
+};
+
+template <class _T1, class _T2>
+struct _LIBCPP_TEMPLATE_VIS tuple_element<1, pair<_T1, _T2> >
+{
+    typedef _LIBCPP_NODEBUG _T2 type;
+};
+
+template <size_t _Ip> struct __get_pair;
+
+template <>
+struct __get_pair<0>
+{
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    _T1&
+    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
+
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const _T1&
+    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    _T1&&
+    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T1>(__p.first);}
+
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const _T1&&
+    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T1>(__p.first);}
+#endif // _LIBCPP_CXX03_LANG
+};
+
+template <>
+struct __get_pair<1>
+{
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    _T2&
+    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
+
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const _T2&
+    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    _T2&&
+    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T2>(__p.second);}
+
+    template <class _T1, class _T2>
+    static
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const _T2&&
+    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T2>(__p.second);}
+#endif // _LIBCPP_CXX03_LANG
+};
+
+template <size_t _Ip, class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename tuple_element<_Ip, pair<_T1, _T2> >::type&
+get(pair<_T1, _T2>& __p) _NOEXCEPT
+{
+    return __get_pair<_Ip>::get(__p);
+}
+
+template <size_t _Ip, class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const typename tuple_element<_Ip, pair<_T1, _T2> >::type&
+get(const pair<_T1, _T2>& __p) _NOEXCEPT
+{
+    return __get_pair<_Ip>::get(__p);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+template <size_t _Ip, class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
+get(pair<_T1, _T2>&& __p) _NOEXCEPT
+{
+    return __get_pair<_Ip>::get(_VSTD::move(__p));
+}
+
+template <size_t _Ip, class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
+get(const pair<_T1, _T2>&& __p) _NOEXCEPT
+{
+    return __get_pair<_Ip>::get(_VSTD::move(__p));
+}
+#endif // _LIBCPP_CXX03_LANG
+
+#if _LIBCPP_STD_VER > 11
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 & get(pair<_T1, _T2>& __p) _NOEXCEPT
+{
+    return __get_pair<0>::get(__p);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 const & get(pair<_T1, _T2> const& __p) _NOEXCEPT
+{
+    return __get_pair<0>::get(__p);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 && get(pair<_T1, _T2>&& __p) _NOEXCEPT
+{
+    return __get_pair<0>::get(_VSTD::move(__p));
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 const && get(pair<_T1, _T2> const&& __p) _NOEXCEPT
+{
+    return __get_pair<0>::get(_VSTD::move(__p));
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 & get(pair<_T2, _T1>& __p) _NOEXCEPT
+{
+    return __get_pair<1>::get(__p);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 const & get(pair<_T2, _T1> const& __p) _NOEXCEPT
+{
+    return __get_pair<1>::get(__p);
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 && get(pair<_T2, _T1>&& __p) _NOEXCEPT
+{
+    return __get_pair<1>::get(_VSTD::move(__p));
+}
+
+template <class _T1, class _T2>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 const && get(pair<_T2, _T1> const&& __p) _NOEXCEPT
+{
+    return __get_pair<1>::get(_VSTD::move(__p));
+}
+
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_PAIR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/piecewise_construct.h b/contrib/libs/cxxsupp/libcxx/include/__utility/piecewise_construct.h
new file mode 100644
index 00000000000..4dc44b38fe9
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/piecewise_construct.h
@@ -0,0 +1,29 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_PIECEWISE_CONSTRUCT_H
+#define _LIBCPP___UTILITY_PIECEWISE_CONSTRUCT_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+struct _LIBCPP_TEMPLATE_VIS piecewise_construct_t { explicit piecewise_construct_t() = default; };
+#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
+extern _LIBCPP_EXPORTED_FROM_ABI const piecewise_construct_t piecewise_construct;// = piecewise_construct_t();
+#else
+/* inline */ constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_PIECEWISE_CONSTRUCT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/rel_ops.h b/contrib/libs/cxxsupp/libcxx/include/__utility/rel_ops.h
new file mode 100644
index 00000000000..c94b8fddafe
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/rel_ops.h
@@ -0,0 +1,62 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_REL_OPS_H
+#define _LIBCPP___UTILITY_REL_OPS_H
+
+#include <__config>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace rel_ops
+{
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const _Tp& __x, const _Tp& __y)
+{
+    return !(__x == __y);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const _Tp& __x, const _Tp& __y)
+{
+    return __y < __x;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const _Tp& __x, const _Tp& __y)
+{
+    return !(__y < __x);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const _Tp& __x, const _Tp& __y)
+{
+    return !(__x < __y);
+}
+
+}  // rel_ops
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_REL_OPS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/swap.h b/contrib/libs/cxxsupp/libcxx/include/__utility/swap.h
new file mode 100644
index 00000000000..6c07511686f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/swap.h
@@ -0,0 +1,50 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_SWAP_H
+#define _LIBCPP___UTILITY_SWAP_H
+
+#include <__config>
+#include <__utility/declval.h>
+#include <__utility/move.h>
+#include <type_traits>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp>
+using __swap_result_t = typename enable_if<is_move_constructible<_Tp>::value && is_move_assignable<_Tp>::value>::type;
+#else
+template <class>
+using __swap_result_t = void;
+#endif
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY __swap_result_t<_Tp> _LIBCPP_CONSTEXPR_AFTER_CXX17 swap(_Tp& __x, _Tp& __y)
+    _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value&& is_nothrow_move_assignable<_Tp>::value) {
+  _Tp __t(_VSTD::move(__x));
+  __x = _VSTD::move(__y);
+  __y = _VSTD::move(__t);
+}
+
+template <class _Tp, size_t _Np>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 typename enable_if<__is_swappable<_Tp>::value>::type
+swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value) {
+  for (size_t __i = 0; __i != _Np; ++__i) {
+    swap(__a[__i], __b[__i]);
+  }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_SWAP_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__utility/to_underlying.h b/contrib/libs/cxxsupp/libcxx/include/__utility/to_underlying.h
new file mode 100644
index 00000000000..084d3694e5d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__utility/to_underlying.h
@@ -0,0 +1,40 @@
+// -*- C++ -*-
+//===----------------- __utility/to_underlying.h --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___UTILITY_TO_UNDERLYING_H
+#define _LIBCPP___UTILITY_TO_UNDERLYING_H
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr typename underlying_type<_Tp>::type
+__to_underlying(_Tp __val) noexcept {
+  return static_cast<typename underlying_type<_Tp>::type>(__val);
+}
+#endif // !_LIBCPP_CXX03_LANG
+
+#if _LIBCPP_STD_VER > 20
+template <class _Tp>
+_LIBCPP_NODISCARD_EXT _LIBCPP_INLINE_VISIBILITY constexpr underlying_type_t<_Tp>
+to_underlying(_Tp __val) noexcept {
+  return _VSTD::__to_underlying(__val);
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___UTILITY_TO_UNDERLYING_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__variant/monostate.h b/contrib/libs/cxxsupp/libcxx/include/__variant/monostate.h
new file mode 100644
index 00000000000..d575847340a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__variant/monostate.h
@@ -0,0 +1,60 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___VARIANT_MONOSTATE_H
+#define _LIBCPP___VARIANT_MONOSTATE_H
+
+#include <__config>
+#include <__functional/hash.h>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+struct _LIBCPP_TEMPLATE_VIS monostate {};
+
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool operator<(monostate, monostate) noexcept { return false; }
+
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool operator>(monostate, monostate) noexcept { return false; }
+
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool operator<=(monostate, monostate) noexcept { return true; }
+
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool operator>=(monostate, monostate) noexcept { return true; }
+
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool operator==(monostate, monostate) noexcept { return true; }
+
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool operator!=(monostate, monostate) noexcept { return false; }
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<monostate> {
+  using argument_type = monostate;
+  using result_type = size_t;
+
+  inline _LIBCPP_INLINE_VISIBILITY
+  result_type operator()(const argument_type&) const _NOEXCEPT {
+    return 66740831; // return a fundamentally attractive random value.
+  }
+};
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___VARIANT_MONOSTATE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/__wrappers_config b/contrib/libs/cxxsupp/libcxx/include/__wrappers_config
new file mode 100644
index 00000000000..934e7c92796
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/__wrappers_config
@@ -0,0 +1,39 @@
+#pragma once
+
+#if !defined(NDEBUG) && !defined(_LIBCPP_DEBUG)
+#   define _LIBCPP_DEBUG 0
+#endif
+
+#ifndef _YNDX_LIBCPP_ENABLE_EXTENSIONS
+#   define _YNDX_LIBCPP_ENABLE_EXTENSIONS 1
+#endif
+
+#if _YNDX_LIBCPP_ENABLE_EXTENSIONS == 1
+#   define _YNDX_LIBCXX_ENABLE_STRING_RESIZE_UNINITIALIZED 1
+#   define _YNDX_LIBCXX_ENABLE_VECTOR_BOOL_COMPRESSION 0
+#   define _YNDX_LIBCXX_ENABLE_VECTOR_POD_RESIZE_UNINITIALIZED 1
+#else
+#   define _YNDX_LIBCXX_ENABLE_STRING_RESIZE_UNINITIALIZED 0
+#   define _YNDX_LIBCXX_ENABLE_VECTOR_BOOL_COMPRESSION 1
+#   define _YNDX_LIBCXX_ENABLE_VECTOR_POD_RESIZE_UNINITIALIZED 0
+#endif
+
+#if _YNDX_LIBCPP_ENABLE_EXTENSIONS == 1 && (!defined(_LIBCPP_DEBUG) || _LIBCPP_DEBUG == 0)
+#   define _YNDX_LIBCPP_MAKE_VECTOR_ITERATOR_POINTERS  1
+#   define _YNDX_LIBCPP_MAKE_STRING_ITERATOR_POINTERS  1
+#else
+#   define _YNDX_LIBCPP_MAKE_VECTOR_ITERATOR_POINTERS  0
+#   define _YNDX_LIBCPP_MAKE_STRING_ITERATOR_POINTERS  0
+#endif
+
+#define _YNDX_WIN32_NOFILESYSTEM_RUNTIME
+
+#define _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS
+#define _LIBCPP_NO_AUTO_LINK
+#define _LIBCPP_DISABLE_DEPRECATION_WARNINGS
+#define _LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS
+#define _LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS
+
+#ifdef _musl_
+#   define _LIBCPP_HAS_MUSL_LIBC
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/include/algorithm b/contrib/libs/cxxsupp/libcxx/include/algorithm
new file mode 100644
index 00000000000..3fe0c8c1c9c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/algorithm
@@ -0,0 +1,765 @@
+// -*- C++ -*-
+//===-------------------------- algorithm ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_ALGORITHM
+#define _LIBCPP_ALGORITHM
+
+/*
+    algorithm synopsis
+
+#include <initializer_list>
+
+namespace std
+{
+
+template <class InputIterator, class Predicate>
+    constexpr bool     // constexpr in C++20
+    all_of(InputIterator first, InputIterator last, Predicate pred);
+
+template <class InputIterator, class Predicate>
+    constexpr bool     // constexpr in C++20
+    any_of(InputIterator first, InputIterator last, Predicate pred);
+
+template <class InputIterator, class Predicate>
+    constexpr bool     // constexpr in C++20
+    none_of(InputIterator first, InputIterator last, Predicate pred);
+
+template <class InputIterator, class Function>
+    constexpr Function          // constexpr in C++20
+    for_each(InputIterator first, InputIterator last, Function f);
+
+template<class InputIterator, class Size, class Function>
+    constexpr InputIterator     // constexpr in C++20
+    for_each_n(InputIterator first, Size n, Function f); // C++17
+
+template <class InputIterator, class T>
+    constexpr InputIterator     // constexpr in C++20
+    find(InputIterator first, InputIterator last, const T& value);
+
+template <class InputIterator, class Predicate>
+    constexpr InputIterator     // constexpr in C++20
+    find_if(InputIterator first, InputIterator last, Predicate pred);
+
+template<class InputIterator, class Predicate>
+    constexpr InputIterator     // constexpr in C++20
+    find_if_not(InputIterator first, InputIterator last, Predicate pred);
+
+template <class ForwardIterator1, class ForwardIterator2>
+    constexpr ForwardIterator1  // constexpr in C++20
+    find_end(ForwardIterator1 first1, ForwardIterator1 last1,
+             ForwardIterator2 first2, ForwardIterator2 last2);
+
+template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
+    constexpr ForwardIterator1  // constexpr in C++20
+    find_end(ForwardIterator1 first1, ForwardIterator1 last1,
+             ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
+
+template <class ForwardIterator1, class ForwardIterator2>
+    constexpr ForwardIterator1  // constexpr in C++20
+    find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
+                  ForwardIterator2 first2, ForwardIterator2 last2);
+
+template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
+    constexpr ForwardIterator1  // constexpr in C++20
+    find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
+                  ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
+
+template <class ForwardIterator>
+    constexpr ForwardIterator   // constexpr in C++20
+    adjacent_find(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class BinaryPredicate>
+    constexpr ForwardIterator   // constexpr in C++20
+    adjacent_find(ForwardIterator first, ForwardIterator last, BinaryPredicate pred);
+
+template <class InputIterator, class T>
+    constexpr typename iterator_traits<InputIterator>::difference_type  // constexpr in C++20
+    count(InputIterator first, InputIterator last, const T& value);
+
+template <class InputIterator, class Predicate>
+    constexpr typename iterator_traits<InputIterator>::difference_type // constexpr in C++20
+    count_if(InputIterator first, InputIterator last, Predicate pred);
+
+template <class InputIterator1, class InputIterator2>
+    constexpr pair<InputIterator1, InputIterator2>   // constexpr in C++20
+    mismatch(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);
+
+template <class InputIterator1, class InputIterator2>
+    constexpr pair<InputIterator1, InputIterator2>   // constexpr in C++20
+    mismatch(InputIterator1 first1, InputIterator1 last1,
+             InputIterator2 first2, InputIterator2 last2); // **C++14**
+
+template <class InputIterator1, class InputIterator2, class BinaryPredicate>
+    constexpr pair<InputIterator1, InputIterator2>   // constexpr in C++20
+    mismatch(InputIterator1 first1, InputIterator1 last1,
+             InputIterator2 first2, BinaryPredicate pred);
+
+template <class InputIterator1, class InputIterator2, class BinaryPredicate>
+    constexpr pair<InputIterator1, InputIterator2>   // constexpr in C++20
+    mismatch(InputIterator1 first1, InputIterator1 last1,
+             InputIterator2 first2, InputIterator2 last2,
+             BinaryPredicate pred); // **C++14**
+
+template <class InputIterator1, class InputIterator2>
+    constexpr bool      // constexpr in C++20
+    equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);
+
+template <class InputIterator1, class InputIterator2>
+    constexpr bool      // constexpr in C++20
+    equal(InputIterator1 first1, InputIterator1 last1,
+          InputIterator2 first2, InputIterator2 last2); // **C++14**
+
+template <class InputIterator1, class InputIterator2, class BinaryPredicate>
+    constexpr bool      // constexpr in C++20
+    equal(InputIterator1 first1, InputIterator1 last1,
+          InputIterator2 first2, BinaryPredicate pred);
+
+template <class InputIterator1, class InputIterator2, class BinaryPredicate>
+    constexpr bool      // constexpr in C++20
+    equal(InputIterator1 first1, InputIterator1 last1,
+          InputIterator2 first2, InputIterator2 last2,
+          BinaryPredicate pred); // **C++14**
+
+template<class ForwardIterator1, class ForwardIterator2>
+    constexpr bool      // constexpr in C++20
+    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
+                   ForwardIterator2 first2);
+
+template<class ForwardIterator1, class ForwardIterator2>
+    constexpr bool      // constexpr in C++20
+    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
+                   ForwardIterator2 first2, ForwardIterator2 last2); // **C++14**
+
+template<class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
+    constexpr bool      // constexpr in C++20
+    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
+                   ForwardIterator2 first2, BinaryPredicate pred);
+
+template<class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
+    constexpr bool      // constexpr in C++20
+    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
+                   ForwardIterator2 first2, ForwardIterator2 last2,
+                   BinaryPredicate pred);  // **C++14**
+
+template <class ForwardIterator1, class ForwardIterator2>
+    constexpr ForwardIterator1      // constexpr in C++20
+    search(ForwardIterator1 first1, ForwardIterator1 last1,
+           ForwardIterator2 first2, ForwardIterator2 last2);
+
+template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
+    constexpr ForwardIterator1      // constexpr in C++20
+    search(ForwardIterator1 first1, ForwardIterator1 last1,
+           ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
+
+template <class ForwardIterator, class Size, class T>
+    constexpr ForwardIterator       // constexpr in C++20
+    search_n(ForwardIterator first, ForwardIterator last, Size count, const T& value);
+
+template <class ForwardIterator, class Size, class T, class BinaryPredicate>
+    constexpr ForwardIterator       // constexpr in C++20
+    search_n(ForwardIterator first, ForwardIterator last,
+             Size count, const T& value, BinaryPredicate pred);
+
+template <class InputIterator, class OutputIterator>
+    constexpr OutputIterator      // constexpr in C++20
+    copy(InputIterator first, InputIterator last, OutputIterator result);
+
+template<class InputIterator, class OutputIterator, class Predicate>
+    constexpr OutputIterator      // constexpr in C++20
+    copy_if(InputIterator first, InputIterator last,
+            OutputIterator result, Predicate pred);
+
+template<class InputIterator, class Size, class OutputIterator>
+    constexpr OutputIterator      // constexpr in C++20
+    copy_n(InputIterator first, Size n, OutputIterator result);
+
+template <class BidirectionalIterator1, class BidirectionalIterator2>
+    constexpr BidirectionalIterator2      // constexpr in C++20
+    copy_backward(BidirectionalIterator1 first, BidirectionalIterator1 last,
+                  BidirectionalIterator2 result);
+
+template <class ForwardIterator1, class ForwardIterator2>
+    constexpr ForwardIterator2    // constexpr in C++20
+    swap_ranges(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2);
+
+template <class ForwardIterator1, class ForwardIterator2>
+    constexpr void                // constexpr in C++20
+    iter_swap(ForwardIterator1 a, ForwardIterator2 b);
+
+template <class InputIterator, class OutputIterator, class UnaryOperation>
+    constexpr OutputIterator      // constexpr in C++20
+    transform(InputIterator first, InputIterator last, OutputIterator result, UnaryOperation op);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator, class BinaryOperation>
+    constexpr OutputIterator      // constexpr in C++20
+    transform(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2,
+              OutputIterator result, BinaryOperation binary_op);
+
+template <class ForwardIterator, class T>
+    constexpr void      // constexpr in C++20
+    replace(ForwardIterator first, ForwardIterator last, const T& old_value, const T& new_value);
+
+template <class ForwardIterator, class Predicate, class T>
+    constexpr void      // constexpr in C++20
+    replace_if(ForwardIterator first, ForwardIterator last, Predicate pred, const T& new_value);
+
+template <class InputIterator, class OutputIterator, class T>
+    constexpr OutputIterator      // constexpr in C++20
+    replace_copy(InputIterator first, InputIterator last, OutputIterator result,
+                 const T& old_value, const T& new_value);
+
+template <class InputIterator, class OutputIterator, class Predicate, class T>
+    constexpr OutputIterator      // constexpr in C++20
+    replace_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred, const T& new_value);
+
+template <class ForwardIterator, class T>
+    constexpr void      // constexpr in C++20
+    fill(ForwardIterator first, ForwardIterator last, const T& value);
+
+template <class OutputIterator, class Size, class T>
+    constexpr OutputIterator      // constexpr in C++20
+    fill_n(OutputIterator first, Size n, const T& value);
+
+template <class ForwardIterator, class Generator>
+    constexpr void      // constexpr in C++20
+    generate(ForwardIterator first, ForwardIterator last, Generator gen);
+
+template <class OutputIterator, class Size, class Generator>
+    constexpr OutputIterator      // constexpr in C++20
+    generate_n(OutputIterator first, Size n, Generator gen);
+
+template <class ForwardIterator, class T>
+    constexpr ForwardIterator     // constexpr in C++20
+    remove(ForwardIterator first, ForwardIterator last, const T& value);
+
+template <class ForwardIterator, class Predicate>
+    constexpr ForwardIterator     // constexpr in C++20
+    remove_if(ForwardIterator first, ForwardIterator last, Predicate pred);
+
+template <class InputIterator, class OutputIterator, class T>
+    constexpr OutputIterator     // constexpr in C++20
+    remove_copy(InputIterator first, InputIterator last, OutputIterator result, const T& value);
+
+template <class InputIterator, class OutputIterator, class Predicate>
+    constexpr OutputIterator     // constexpr in C++20
+    remove_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred);
+
+template <class ForwardIterator>
+    constexpr ForwardIterator    // constexpr in C++20
+    unique(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class BinaryPredicate>
+    constexpr ForwardIterator    // constexpr in C++20
+    unique(ForwardIterator first, ForwardIterator last, BinaryPredicate pred);
+
+template <class InputIterator, class OutputIterator>
+    constexpr OutputIterator     // constexpr in C++20
+    unique_copy(InputIterator first, InputIterator last, OutputIterator result);
+
+template <class InputIterator, class OutputIterator, class BinaryPredicate>
+    constexpr OutputIterator     // constexpr in C++20
+    unique_copy(InputIterator first, InputIterator last, OutputIterator result, BinaryPredicate pred);
+
+template <class BidirectionalIterator>
+    constexpr void               // constexpr in C++20
+    reverse(BidirectionalIterator first, BidirectionalIterator last);
+
+template <class BidirectionalIterator, class OutputIterator>
+    constexpr OutputIterator       // constexpr in C++20
+    reverse_copy(BidirectionalIterator first, BidirectionalIterator last, OutputIterator result);
+
+template <class ForwardIterator>
+    constexpr ForwardIterator      // constexpr in C++20
+    rotate(ForwardIterator first, ForwardIterator middle, ForwardIterator last);
+
+template <class ForwardIterator, class OutputIterator>
+    constexpr OutputIterator       // constexpr in C++20
+    rotate_copy(ForwardIterator first, ForwardIterator middle, ForwardIterator last, OutputIterator result);
+
+template <class RandomAccessIterator>
+    void
+    random_shuffle(RandomAccessIterator first, RandomAccessIterator last); // deprecated in C++14, removed in C++17
+
+template <class RandomAccessIterator, class RandomNumberGenerator>
+    void
+    random_shuffle(RandomAccessIterator first, RandomAccessIterator last,
+                   RandomNumberGenerator& rand);  // deprecated in C++14, removed in C++17
+
+template<class PopulationIterator, class SampleIterator,
+         class Distance, class UniformRandomBitGenerator>
+    SampleIterator sample(PopulationIterator first, PopulationIterator last,
+                          SampleIterator out, Distance n,
+                          UniformRandomBitGenerator&& g); // C++17
+
+template<class RandomAccessIterator, class UniformRandomNumberGenerator>
+    void shuffle(RandomAccessIterator first, RandomAccessIterator last,
+                 UniformRandomNumberGenerator&& g);
+
+template<class ForwardIterator>
+  constexpr ForwardIterator
+    shift_left(ForwardIterator first, ForwardIterator last,
+               typename iterator_traits<ForwardIterator>::difference_type n); // C++20
+
+template<class ForwardIterator>
+  constexpr ForwardIterator
+    shift_right(ForwardIterator first, ForwardIterator last,
+                typename iterator_traits<ForwardIterator>::difference_type n); // C++20
+
+template <class InputIterator, class Predicate>
+    constexpr bool  // constexpr in C++20
+    is_partitioned(InputIterator first, InputIterator last, Predicate pred);
+
+template <class ForwardIterator, class Predicate>
+    constexpr ForwardIterator  // constexpr in C++20
+    partition(ForwardIterator first, ForwardIterator last, Predicate pred);
+
+template <class InputIterator, class OutputIterator1,
+          class OutputIterator2, class Predicate>
+    constexpr pair<OutputIterator1, OutputIterator2>   // constexpr in C++20
+    partition_copy(InputIterator first, InputIterator last,
+                   OutputIterator1 out_true, OutputIterator2 out_false,
+                   Predicate pred);
+
+template <class ForwardIterator, class Predicate>
+    ForwardIterator
+    stable_partition(ForwardIterator first, ForwardIterator last, Predicate pred);
+
+template<class ForwardIterator, class Predicate>
+    constexpr ForwardIterator  // constexpr in C++20
+    partition_point(ForwardIterator first, ForwardIterator last, Predicate pred);
+
+template <class ForwardIterator>
+    constexpr bool  // constexpr in C++20
+    is_sorted(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class Compare>
+    constexpr bool  // constexpr in C++20
+    is_sorted(ForwardIterator first, ForwardIterator last, Compare comp);
+
+template<class ForwardIterator>
+    constexpr ForwardIterator    // constexpr in C++20
+    is_sorted_until(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class Compare>
+    constexpr ForwardIterator    // constexpr in C++20
+    is_sorted_until(ForwardIterator first, ForwardIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    constexpr void               // constexpr in C++20
+    sort(RandomAccessIterator first, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    constexpr void               // constexpr in C++20
+    sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    void
+    stable_sort(RandomAccessIterator first, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    void
+    stable_sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    constexpr void                    // constexpr in C++20
+    partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    constexpr void                    // constexpr in C++20
+    partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last, Compare comp);
+
+template <class InputIterator, class RandomAccessIterator>
+    constexpr RandomAccessIterator    // constexpr in C++20
+    partial_sort_copy(InputIterator first, InputIterator last,
+                      RandomAccessIterator result_first, RandomAccessIterator result_last);
+
+template <class InputIterator, class RandomAccessIterator, class Compare>
+    constexpr RandomAccessIterator    // constexpr in C++20
+    partial_sort_copy(InputIterator first, InputIterator last,
+                      RandomAccessIterator result_first, RandomAccessIterator result_last, Compare comp);
+
+template <class RandomAccessIterator>
+    constexpr void                    // constexpr in C++20
+    nth_element(RandomAccessIterator first, RandomAccessIterator nth, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    constexpr void                    // constexpr in C++20
+    nth_element(RandomAccessIterator first, RandomAccessIterator nth, RandomAccessIterator last, Compare comp);
+
+template <class ForwardIterator, class T>
+    constexpr ForwardIterator                         // constexpr in C++20
+    lower_bound(ForwardIterator first, ForwardIterator last, const T& value);
+
+template <class ForwardIterator, class T, class Compare>
+    constexpr ForwardIterator                         // constexpr in C++20
+    lower_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
+
+template <class ForwardIterator, class T>
+    constexpr ForwardIterator                         // constexpr in C++20
+    upper_bound(ForwardIterator first, ForwardIterator last, const T& value);
+
+template <class ForwardIterator, class T, class Compare>
+    constexpr ForwardIterator                         // constexpr in C++20
+    upper_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
+
+template <class ForwardIterator, class T>
+    constexpr pair<ForwardIterator, ForwardIterator>  // constexpr in C++20
+    equal_range(ForwardIterator first, ForwardIterator last, const T& value);
+
+template <class ForwardIterator, class T, class Compare>
+    constexpr pair<ForwardIterator, ForwardIterator>  // constexpr in C++20
+    equal_range(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
+
+template <class ForwardIterator, class T>
+    constexpr bool                                    // constexpr in C++20
+    binary_search(ForwardIterator first, ForwardIterator last, const T& value);
+
+template <class ForwardIterator, class T, class Compare>
+    constexpr bool                                    // constexpr in C++20
+    binary_search(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator>
+    constexpr OutputIterator                          // constexpr in C++20
+    merge(InputIterator1 first1, InputIterator1 last1,
+          InputIterator2 first2, InputIterator2 last2, OutputIterator result);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
+    constexpr OutputIterator                          // constexpr in C++20
+    merge(InputIterator1 first1, InputIterator1 last1,
+          InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
+
+template <class BidirectionalIterator>
+    void
+    inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last);
+
+template <class BidirectionalIterator, class Compare>
+    void
+    inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last, Compare comp);
+
+template <class InputIterator1, class InputIterator2>
+    constexpr bool                                    // constexpr in C++20
+    includes(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2);
+
+template <class InputIterator1, class InputIterator2, class Compare>
+    constexpr bool                                    // constexpr in C++20
+    includes(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, Compare comp);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator>
+    constexpr OutputIterator                          // constexpr in C++20
+    set_union(InputIterator1 first1, InputIterator1 last1,
+              InputIterator2 first2, InputIterator2 last2, OutputIterator result);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
+    constexpr OutputIterator                          // constexpr in C++20
+    set_union(InputIterator1 first1, InputIterator1 last1,
+              InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator>
+    constexpr OutputIterator                         // constexpr in C++20
+    set_intersection(InputIterator1 first1, InputIterator1 last1,
+                     InputIterator2 first2, InputIterator2 last2, OutputIterator result);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
+    constexpr OutputIterator                         // constexpr in C++20
+    set_intersection(InputIterator1 first1, InputIterator1 last1,
+                     InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator>
+    constexpr OutputIterator                         // constexpr in C++20
+    set_difference(InputIterator1 first1, InputIterator1 last1,
+                   InputIterator2 first2, InputIterator2 last2, OutputIterator result);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
+    constexpr OutputIterator                         // constexpr in C++20
+    set_difference(InputIterator1 first1, InputIterator1 last1,
+                   InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator>
+    constexpr OutputIterator                         // constexpr in C++20
+    set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
+                             InputIterator2 first2, InputIterator2 last2, OutputIterator result);
+
+template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
+    constexpr OutputIterator                         // constexpr in C++20
+    set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
+                             InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
+
+template <class RandomAccessIterator>
+    constexpr void                                   // constexpr in C++20
+    push_heap(RandomAccessIterator first, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    constexpr void                                   // constexpr in C++20
+    push_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    constexpr void                                   // constexpr in C++20
+    pop_heap(RandomAccessIterator first, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    constexpr void                                   // constexpr in C++20
+    pop_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    constexpr void                                   // constexpr in C++20
+    make_heap(RandomAccessIterator first, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    constexpr void                                   // constexpr in C++20
+    make_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    constexpr void                                   // constexpr in C++20
+    sort_heap(RandomAccessIterator first, RandomAccessIterator last);
+
+template <class RandomAccessIterator, class Compare>
+    constexpr void                                   // constexpr in C++20
+    sort_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    constexpr bool   // constexpr in C++20
+    is_heap(RandomAccessIterator first, RandomAccessiterator last);
+
+template <class RandomAccessIterator, class Compare>
+    constexpr bool   // constexpr in C++20
+    is_heap(RandomAccessIterator first, RandomAccessiterator last, Compare comp);
+
+template <class RandomAccessIterator>
+    constexpr RandomAccessIterator   // constexpr in C++20
+    is_heap_until(RandomAccessIterator first, RandomAccessiterator last);
+
+template <class RandomAccessIterator, class Compare>
+    constexpr RandomAccessIterator   // constexpr in C++20
+    is_heap_until(RandomAccessIterator first, RandomAccessiterator last, Compare comp);
+
+template <class ForwardIterator>
+    constexpr ForwardIterator        // constexpr in C++14
+    min_element(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class Compare>
+    constexpr ForwardIterator        // constexpr in C++14
+    min_element(ForwardIterator first, ForwardIterator last, Compare comp);
+
+template <class T>
+    constexpr const T&               // constexpr in C++14
+    min(const T& a, const T& b);
+
+template <class T, class Compare>
+    constexpr const T&               // constexpr in C++14
+    min(const T& a, const T& b, Compare comp);
+
+template<class T>
+    constexpr T                      // constexpr in C++14
+    min(initializer_list<T> t);
+
+template<class T, class Compare>
+    constexpr T                      // constexpr in C++14
+    min(initializer_list<T> t, Compare comp);
+
+template<class T>
+    constexpr const T& clamp(const T& v, const T& lo, const T& hi);               // C++17
+
+template<class T, class Compare>
+    constexpr const T& clamp(const T& v, const T& lo, const T& hi, Compare comp); // C++17
+
+template <class ForwardIterator>
+    constexpr ForwardIterator        // constexpr in C++14
+    max_element(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class Compare>
+    constexpr ForwardIterator        // constexpr in C++14
+    max_element(ForwardIterator first, ForwardIterator last, Compare comp);
+
+template <class T>
+    constexpr const T&               // constexpr in C++14
+    max(const T& a, const T& b);
+
+template <class T, class Compare>
+    constexpr const T&               // constexpr in C++14
+    max(const T& a, const T& b, Compare comp);
+
+template<class T>
+    constexpr T                      // constexpr in C++14
+    max(initializer_list<T> t);
+
+template<class T, class Compare>
+    constexpr T                      // constexpr in C++14
+    max(initializer_list<T> t, Compare comp);
+
+template<class ForwardIterator>
+    constexpr pair<ForwardIterator, ForwardIterator>  // constexpr in C++14
+    minmax_element(ForwardIterator first, ForwardIterator last);
+
+template<class ForwardIterator, class Compare>
+    constexpr pair<ForwardIterator, ForwardIterator>  // constexpr in C++14
+    minmax_element(ForwardIterator first, ForwardIterator last, Compare comp);
+
+template<class T>
+    constexpr pair<const T&, const T&>  // constexpr in C++14
+    minmax(const T& a, const T& b);
+
+template<class T, class Compare>
+    constexpr pair<const T&, const T&>  // constexpr in C++14
+    minmax(const T& a, const T& b, Compare comp);
+
+template<class T>
+    constexpr pair<T, T>                // constexpr in C++14
+    minmax(initializer_list<T> t);
+
+template<class T, class Compare>
+    constexpr pair<T, T>                // constexpr in C++14
+    minmax(initializer_list<T> t, Compare comp);
+
+template <class InputIterator1, class InputIterator2>
+    constexpr bool     // constexpr in C++20
+    lexicographical_compare(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2);
+
+template <class InputIterator1, class InputIterator2, class Compare>
+    constexpr bool     // constexpr in C++20
+    lexicographical_compare(InputIterator1 first1, InputIterator1 last1,
+                            InputIterator2 first2, InputIterator2 last2, Compare comp);
+
+template <class BidirectionalIterator>
+    constexpr bool     // constexpr in C++20
+    next_permutation(BidirectionalIterator first, BidirectionalIterator last);
+
+template <class BidirectionalIterator, class Compare>
+    constexpr bool     // constexpr in C++20
+    next_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp);
+
+template <class BidirectionalIterator>
+    constexpr bool     // constexpr in C++20
+    prev_permutation(BidirectionalIterator first, BidirectionalIterator last);
+
+template <class BidirectionalIterator, class Compare>
+    constexpr bool     // constexpr in C++20
+    prev_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__bits> // __libcpp_clz
+#include <cstddef>
+#include <cstring>
+#include <functional>
+#include <initializer_list>
+#include <utility> // needed to provide swap_ranges.
+#include <memory>
+#include <iterator>
+#include <memory>
+#include <type_traits>
+#include <utility> // swap_ranges
+#include <version>
+
+#include <__algorithm/adjacent_find.h>
+#include <__algorithm/all_of.h>
+#include <__algorithm/any_of.h>
+#include <__algorithm/binary_search.h>
+#include <__algorithm/clamp.h>
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/copy.h>
+#include <__algorithm/copy_backward.h>
+#include <__algorithm/copy_if.h>
+#include <__algorithm/copy_n.h>
+#include <__algorithm/count.h>
+#include <__algorithm/count_if.h>
+#include <__algorithm/equal.h>
+#include <__algorithm/equal_range.h>
+#include <__algorithm/fill_n.h>
+#include <__algorithm/fill.h>
+#include <__algorithm/find.h>
+#include <__algorithm/find_end.h>
+#include <__algorithm/find_first_of.h>
+#include <__algorithm/find_if.h>
+#include <__algorithm/find_if_not.h>
+#include <__algorithm/for_each.h>
+#include <__algorithm/for_each_n.h>
+#include <__algorithm/generate_n.h>
+#include <__algorithm/generate.h>
+#include <__algorithm/half_positive.h>
+#include <__algorithm/includes.h>
+#include <__algorithm/inplace_merge.h>
+#include <__algorithm/is_heap.h>
+#include <__algorithm/is_heap_until.h>
+#include <__algorithm/is_partitioned.h>
+#include <__algorithm/is_permutation.h>
+#include <__algorithm/is_sorted.h>
+#include <__algorithm/is_sorted_until.h>
+#include <__algorithm/iter_swap.h>
+#include <__algorithm/lexicographical_compare.h>
+#include <__algorithm/lower_bound.h>
+#include <__algorithm/make_heap.h>
+#include <__algorithm/max.h>
+#include <__algorithm/max_element.h>
+#include <__algorithm/merge.h>
+#include <__algorithm/min.h>
+#include <__algorithm/min_element.h>
+#include <__algorithm/minmax.h>
+#include <__algorithm/minmax_element.h>
+#include <__algorithm/mismatch.h>
+#include <__algorithm/move.h>
+#include <__algorithm/move_backward.h>
+#include <__algorithm/next_permutation.h>
+#include <__algorithm/none_of.h>
+#include <__algorithm/nth_element.h>
+#include <__algorithm/partial_sort.h>
+#include <__algorithm/partial_sort_copy.h>
+#include <__algorithm/partition.h>
+#include <__algorithm/partition_copy.h>
+#include <__algorithm/partition_point.h>
+#include <__algorithm/pop_heap.h>
+#include <__algorithm/prev_permutation.h>
+#include <__algorithm/push_heap.h>
+#include <__algorithm/remove.h>
+#include <__algorithm/remove_copy.h>
+#include <__algorithm/remove_copy_if.h>
+#include <__algorithm/remove_if.h>
+#include <__algorithm/replace.h>
+#include <__algorithm/replace_copy.h>
+#include <__algorithm/replace_copy_if.h>
+#include <__algorithm/replace_if.h>
+#include <__algorithm/reverse.h>
+#include <__algorithm/reverse_copy.h>
+#include <__algorithm/rotate.h>
+#include <__algorithm/rotate_copy.h>
+#include <__algorithm/sample.h>
+#include <__algorithm/search.h>
+#include <__algorithm/search_n.h>
+#include <__algorithm/set_difference.h>
+#include <__algorithm/set_intersection.h>
+#include <__algorithm/set_symmetric_difference.h>
+#include <__algorithm/set_union.h>
+#include <__algorithm/shift_left.h>
+#include <__algorithm/shift_right.h>
+#include <__algorithm/shuffle.h>
+#include <__algorithm/sift_down.h>
+#include <__algorithm/sort.h>
+#include <__algorithm/sort_heap.h>
+#include <__algorithm/stable_partition.h>
+#include <__algorithm/stable_sort.h>
+#include <__algorithm/swap_ranges.h>
+#include <__algorithm/transform.h>
+#include <__algorithm/unique_copy.h>
+#include <__algorithm/unique.h>
+#include <__algorithm/unwrap_iter.h>
+#include <__algorithm/upper_bound.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#if defined(_LIBCPP_HAS_PARALLEL_ALGORITHMS) && _LIBCPP_STD_VER >= 17
+//#   include <__pstl_algorithm>
+#endif
+
+#endif // _LIBCPP_ALGORITHM
diff --git a/contrib/libs/cxxsupp/libcxx/include/any b/contrib/libs/cxxsupp/libcxx/include/any
new file mode 100644
index 00000000000..3a826c4d50b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/any
@@ -0,0 +1,686 @@
+// -*- C++ -*-
+//===------------------------------ any -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_ANY
+#define _LIBCPP_ANY
+
+/*
+   any synopsis
+
+namespace std {
+
+  class bad_any_cast : public bad_cast
+  {
+  public:
+    virtual const char* what() const noexcept;
+  };
+
+  class any
+  {
+  public:
+
+    // 6.3.1 any construct/destruct
+    any() noexcept;
+
+    any(const any& other);
+    any(any&& other) noexcept;
+
+    template <class ValueType>
+      any(ValueType&& value);
+
+    ~any();
+
+    // 6.3.2 any assignments
+    any& operator=(const any& rhs);
+    any& operator=(any&& rhs) noexcept;
+
+    template <class ValueType>
+      any& operator=(ValueType&& rhs);
+
+    // 6.3.3 any modifiers
+    template <class ValueType, class... Args>
+      decay_t<ValueType>& emplace(Args&&... args);
+    template <class ValueType, class U, class... Args>
+      decay_t<ValueType>& emplace(initializer_list<U>, Args&&...);
+    void reset() noexcept;
+    void swap(any& rhs) noexcept;
+
+    // 6.3.4 any observers
+    bool has_value() const noexcept;
+    const type_info& type() const noexcept;
+  };
+
+   // 6.4 Non-member functions
+  void swap(any& x, any& y) noexcept;
+
+  template <class T, class ...Args>
+    any make_any(Args&& ...args);
+  template <class T, class U, class ...Args>
+    any make_any(initializer_list<U>, Args&& ...args);
+
+  template<class ValueType>
+    ValueType any_cast(const any& operand);
+  template<class ValueType>
+    ValueType any_cast(any& operand);
+  template<class ValueType>
+    ValueType any_cast(any&& operand);
+
+  template<class ValueType>
+    const ValueType* any_cast(const any* operand) noexcept;
+  template<class ValueType>
+    ValueType* any_cast(any* operand) noexcept;
+
+} // namespace std
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <__utility/forward.h>
+#include <cstdlib>
+#include <memory>
+#include <type_traits>
+#include <typeinfo>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+namespace std {
+class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_BAD_ANY_CAST bad_any_cast : public bad_cast
+{
+public:
+    virtual const char* what() const _NOEXCEPT;
+};
+} // namespace std
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
+void __throw_bad_any_cast()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw bad_any_cast();
+#else
+    _VSTD::abort();
+#endif
+}
+
+// Forward declarations
+class _LIBCPP_TEMPLATE_VIS any;
+
+template <class _ValueType>
+_LIBCPP_INLINE_VISIBILITY
+add_pointer_t<add_const_t<_ValueType>>
+any_cast(any const *) _NOEXCEPT;
+
+template <class _ValueType>
+_LIBCPP_INLINE_VISIBILITY
+add_pointer_t<_ValueType> any_cast(any *) _NOEXCEPT;
+
+namespace __any_imp
+{
+  using _Buffer = aligned_storage_t<3*sizeof(void*), alignment_of<void*>::value>;
+
+  template <class _Tp>
+  using _IsSmallObject = integral_constant<bool
+        , sizeof(_Tp) <= sizeof(_Buffer)
+          && alignment_of<_Buffer>::value
+             % alignment_of<_Tp>::value == 0
+          && is_nothrow_move_constructible<_Tp>::value
+        >;
+
+  enum class _Action {
+    _Destroy,
+    _Copy,
+    _Move,
+    _Get,
+    _TypeInfo
+  };
+
+  template <class _Tp> struct _SmallHandler;
+  template <class _Tp> struct _LargeHandler;
+
+  template <class _Tp>
+  struct  _LIBCPP_TEMPLATE_VIS __unique_typeinfo { static constexpr int __id = 0; };
+  template <class _Tp> constexpr int __unique_typeinfo<_Tp>::__id;
+
+  template <class _Tp>
+  inline _LIBCPP_INLINE_VISIBILITY
+  constexpr const void* __get_fallback_typeid() {
+      return &__unique_typeinfo<remove_cv_t<remove_reference_t<_Tp>>>::__id;
+  }
+
+  template <class _Tp>
+  inline _LIBCPP_INLINE_VISIBILITY
+  bool __compare_typeid(type_info const* __id, const void* __fallback_id)
+  {
+#if !defined(_LIBCPP_NO_RTTI)
+      if (__id && *__id == typeid(_Tp))
+          return true;
+#endif
+      if (!__id && __fallback_id == __any_imp::__get_fallback_typeid<_Tp>())
+          return true;
+      return false;
+  }
+
+  template <class _Tp>
+  using _Handler = conditional_t<
+    _IsSmallObject<_Tp>::value, _SmallHandler<_Tp>, _LargeHandler<_Tp>>;
+
+} // namespace __any_imp
+
+class _LIBCPP_TEMPLATE_VIS any
+{
+public:
+  // construct/destruct
+  _LIBCPP_INLINE_VISIBILITY
+  constexpr any() _NOEXCEPT : __h(nullptr) {}
+
+  _LIBCPP_INLINE_VISIBILITY
+  any(any const & __other) : __h(nullptr)
+  {
+    if (__other.__h) __other.__call(_Action::_Copy, this);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  any(any && __other) _NOEXCEPT : __h(nullptr)
+  {
+    if (__other.__h) __other.__call(_Action::_Move, this);
+  }
+
+  template <
+      class _ValueType
+    , class _Tp = decay_t<_ValueType>
+    , class = enable_if_t<
+        !is_same<_Tp, any>::value &&
+        !__is_inplace_type<_ValueType>::value &&
+        is_copy_constructible<_Tp>::value>
+    >
+  _LIBCPP_INLINE_VISIBILITY
+  any(_ValueType && __value);
+
+  template <class _ValueType, class ..._Args,
+    class _Tp = decay_t<_ValueType>,
+    class = enable_if_t<
+        is_constructible<_Tp, _Args...>::value &&
+        is_copy_constructible<_Tp>::value
+    >
+  >
+  _LIBCPP_INLINE_VISIBILITY
+  explicit any(in_place_type_t<_ValueType>, _Args&&... __args);
+
+  template <class _ValueType, class _Up, class ..._Args,
+    class _Tp = decay_t<_ValueType>,
+    class = enable_if_t<
+        is_constructible<_Tp, initializer_list<_Up>&, _Args...>::value &&
+        is_copy_constructible<_Tp>::value>
+  >
+  _LIBCPP_INLINE_VISIBILITY
+  explicit any(in_place_type_t<_ValueType>, initializer_list<_Up>, _Args&&... __args);
+
+  _LIBCPP_INLINE_VISIBILITY
+  ~any() { this->reset(); }
+
+  // assignments
+  _LIBCPP_INLINE_VISIBILITY
+  any & operator=(any const & __rhs) {
+    any(__rhs).swap(*this);
+    return *this;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  any & operator=(any && __rhs) _NOEXCEPT {
+    any(_VSTD::move(__rhs)).swap(*this);
+    return *this;
+  }
+
+  template <
+      class _ValueType
+    , class _Tp = decay_t<_ValueType>
+    , class = enable_if_t<
+          !is_same<_Tp, any>::value
+          && is_copy_constructible<_Tp>::value>
+    >
+  _LIBCPP_INLINE_VISIBILITY
+  any & operator=(_ValueType && __rhs);
+
+  template <class _ValueType, class ..._Args,
+    class _Tp = decay_t<_ValueType>,
+    class = enable_if_t<
+        is_constructible<_Tp, _Args...>::value &&
+        is_copy_constructible<_Tp>::value>
+    >
+  _LIBCPP_INLINE_VISIBILITY
+  _Tp& emplace(_Args&&... args);
+
+  template <class _ValueType, class _Up, class ..._Args,
+    class _Tp = decay_t<_ValueType>,
+    class = enable_if_t<
+        is_constructible<_Tp, initializer_list<_Up>&, _Args...>::value &&
+        is_copy_constructible<_Tp>::value>
+  >
+  _LIBCPP_INLINE_VISIBILITY
+  _Tp& emplace(initializer_list<_Up>, _Args&&...);
+
+  // 6.3.3 any modifiers
+  _LIBCPP_INLINE_VISIBILITY
+  void reset() _NOEXCEPT { if (__h) this->__call(_Action::_Destroy); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void swap(any & __rhs) _NOEXCEPT;
+
+  // 6.3.4 any observers
+  _LIBCPP_INLINE_VISIBILITY
+  bool has_value() const _NOEXCEPT { return __h != nullptr; }
+
+#if !defined(_LIBCPP_NO_RTTI)
+  _LIBCPP_INLINE_VISIBILITY
+  const type_info & type() const _NOEXCEPT {
+    if (__h) {
+        return *static_cast<type_info const *>(this->__call(_Action::_TypeInfo));
+    } else {
+        return typeid(void);
+    }
+  }
+#endif
+
+private:
+    typedef __any_imp::_Action _Action;
+    using _HandleFuncPtr =  void* (*)(_Action, any const *, any *, const type_info *,
+      const void* __fallback_info);
+
+    union _Storage {
+        constexpr _Storage() : __ptr(nullptr) {}
+        void *  __ptr;
+        __any_imp::_Buffer __buf;
+    };
+
+    _LIBCPP_INLINE_VISIBILITY
+    void * __call(_Action __a, any * __other = nullptr,
+                  type_info const * __info = nullptr,
+                   const void* __fallback_info = nullptr) const
+    {
+        return __h(__a, this, __other, __info, __fallback_info);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void * __call(_Action __a, any * __other = nullptr,
+                  type_info const * __info = nullptr,
+                  const void* __fallback_info = nullptr)
+    {
+        return __h(__a, this, __other, __info, __fallback_info);
+    }
+
+    template <class>
+    friend struct __any_imp::_SmallHandler;
+    template <class>
+    friend struct __any_imp::_LargeHandler;
+
+    template <class _ValueType>
+    friend add_pointer_t<add_const_t<_ValueType>>
+    any_cast(any const *) _NOEXCEPT;
+
+    template <class _ValueType>
+    friend add_pointer_t<_ValueType>
+    any_cast(any *) _NOEXCEPT;
+
+    _HandleFuncPtr __h = nullptr;
+    _Storage __s;
+};
+
+namespace __any_imp
+{
+  template <class _Tp>
+  struct _LIBCPP_TEMPLATE_VIS _SmallHandler
+  {
+     _LIBCPP_INLINE_VISIBILITY
+     static void* __handle(_Action __act, any const * __this, any * __other,
+                           type_info const * __info, const void* __fallback_info)
+     {
+        switch (__act)
+        {
+        case _Action::_Destroy:
+          __destroy(const_cast<any &>(*__this));
+          return nullptr;
+        case _Action::_Copy:
+            __copy(*__this, *__other);
+            return nullptr;
+        case _Action::_Move:
+          __move(const_cast<any &>(*__this), *__other);
+          return nullptr;
+        case _Action::_Get:
+            return __get(const_cast<any &>(*__this), __info, __fallback_info);
+        case _Action::_TypeInfo:
+          return __type_info();
+        }
+    }
+
+    template <class ..._Args>
+    _LIBCPP_INLINE_VISIBILITY
+    static _Tp& __create(any & __dest, _Args&&... __args) {
+        typedef allocator<_Tp> _Alloc;
+        typedef allocator_traits<_Alloc> _ATraits;
+        _Alloc __a;
+        _Tp * __ret = static_cast<_Tp*>(static_cast<void*>(&__dest.__s.__buf));
+        _ATraits::construct(__a, __ret, _VSTD::forward<_Args>(__args)...);
+        __dest.__h = &_SmallHandler::__handle;
+        return *__ret;
+    }
+
+  private:
+    _LIBCPP_INLINE_VISIBILITY
+    static void __destroy(any & __this) {
+        typedef allocator<_Tp> _Alloc;
+        typedef allocator_traits<_Alloc> _ATraits;
+        _Alloc __a;
+        _Tp * __p = static_cast<_Tp *>(static_cast<void*>(&__this.__s.__buf));
+        _ATraits::destroy(__a, __p);
+        __this.__h = nullptr;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void __copy(any const & __this, any & __dest) {
+        _SmallHandler::__create(__dest, *static_cast<_Tp const *>(
+            static_cast<void const *>(&__this.__s.__buf)));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void __move(any & __this, any & __dest) {
+        _SmallHandler::__create(__dest, _VSTD::move(
+            *static_cast<_Tp*>(static_cast<void*>(&__this.__s.__buf))));
+        __destroy(__this);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void* __get(any & __this,
+                       type_info const * __info,
+                       const void* __fallback_id)
+    {
+        if (__any_imp::__compare_typeid<_Tp>(__info, __fallback_id))
+            return static_cast<void*>(&__this.__s.__buf);
+        return nullptr;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void* __type_info()
+    {
+#if !defined(_LIBCPP_NO_RTTI)
+        return const_cast<void*>(static_cast<void const *>(&typeid(_Tp)));
+#else
+        return nullptr;
+#endif
+    }
+  };
+
+  template <class _Tp>
+  struct _LIBCPP_TEMPLATE_VIS _LargeHandler
+  {
+    _LIBCPP_INLINE_VISIBILITY
+    static void* __handle(_Action __act, any const * __this,
+                          any * __other, type_info const * __info,
+                          void const* __fallback_info)
+    {
+        switch (__act)
+        {
+        case _Action::_Destroy:
+          __destroy(const_cast<any &>(*__this));
+          return nullptr;
+        case _Action::_Copy:
+          __copy(*__this, *__other);
+          return nullptr;
+        case _Action::_Move:
+          __move(const_cast<any &>(*__this), *__other);
+          return nullptr;
+        case _Action::_Get:
+            return __get(const_cast<any &>(*__this), __info, __fallback_info);
+        case _Action::_TypeInfo:
+          return __type_info();
+        }
+    }
+
+    template <class ..._Args>
+    _LIBCPP_INLINE_VISIBILITY
+    static _Tp& __create(any & __dest, _Args&&... __args) {
+        typedef allocator<_Tp> _Alloc;
+        typedef allocator_traits<_Alloc> _ATraits;
+        typedef __allocator_destructor<_Alloc> _Dp;
+        _Alloc __a;
+        unique_ptr<_Tp, _Dp> __hold(_ATraits::allocate(__a, 1), _Dp(__a, 1));
+        _Tp * __ret = __hold.get();
+        _ATraits::construct(__a, __ret, _VSTD::forward<_Args>(__args)...);
+        __dest.__s.__ptr = __hold.release();
+        __dest.__h = &_LargeHandler::__handle;
+        return *__ret;
+    }
+
+  private:
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void __destroy(any & __this){
+        typedef allocator<_Tp> _Alloc;
+        typedef allocator_traits<_Alloc> _ATraits;
+        _Alloc __a;
+        _Tp * __p = static_cast<_Tp *>(__this.__s.__ptr);
+        _ATraits::destroy(__a, __p);
+        _ATraits::deallocate(__a, __p, 1);
+        __this.__h = nullptr;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void __copy(any const & __this, any & __dest) {
+        _LargeHandler::__create(__dest, *static_cast<_Tp const *>(__this.__s.__ptr));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void __move(any & __this, any & __dest) {
+      __dest.__s.__ptr = __this.__s.__ptr;
+      __dest.__h = &_LargeHandler::__handle;
+      __this.__h = nullptr;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void* __get(any & __this, type_info const * __info,
+                       void const* __fallback_info)
+    {
+        if (__any_imp::__compare_typeid<_Tp>(__info, __fallback_info))
+            return static_cast<void*>(__this.__s.__ptr);
+        return nullptr;
+
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static void* __type_info()
+    {
+#if !defined(_LIBCPP_NO_RTTI)
+        return const_cast<void*>(static_cast<void const *>(&typeid(_Tp)));
+#else
+        return nullptr;
+#endif
+    }
+  };
+
+} // namespace __any_imp
+
+
+template <class _ValueType, class _Tp, class>
+any::any(_ValueType && __v) : __h(nullptr)
+{
+  __any_imp::_Handler<_Tp>::__create(*this, _VSTD::forward<_ValueType>(__v));
+}
+
+template <class _ValueType, class ..._Args, class _Tp, class>
+any::any(in_place_type_t<_ValueType>, _Args&&... __args) {
+  __any_imp::_Handler<_Tp>::__create(*this, _VSTD::forward<_Args>(__args)...);
+}
+
+template <class _ValueType, class _Up, class ..._Args, class _Tp, class>
+any::any(in_place_type_t<_ValueType>, initializer_list<_Up> __il, _Args&&... __args) {
+  __any_imp::_Handler<_Tp>::__create(*this, __il, _VSTD::forward<_Args>(__args)...);
+}
+
+template <class _ValueType, class, class>
+inline _LIBCPP_INLINE_VISIBILITY
+any & any::operator=(_ValueType && __v)
+{
+  any(_VSTD::forward<_ValueType>(__v)).swap(*this);
+  return *this;
+}
+
+template <class _ValueType, class ..._Args, class _Tp, class>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp& any::emplace(_Args&&... __args) {
+  reset();
+  return __any_imp::_Handler<_Tp>::__create(*this, _VSTD::forward<_Args>(__args)...);
+}
+
+template <class _ValueType, class _Up, class ..._Args, class _Tp, class>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp& any::emplace(initializer_list<_Up> __il, _Args&&... __args) {
+  reset();
+  return __any_imp::_Handler<_Tp>::__create(*this, __il, _VSTD::forward<_Args>(__args)...);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void any::swap(any & __rhs) _NOEXCEPT
+{
+    if (this == &__rhs)
+      return;
+    if (__h && __rhs.__h) {
+        any __tmp;
+        __rhs.__call(_Action::_Move, &__tmp);
+        this->__call(_Action::_Move, &__rhs);
+        __tmp.__call(_Action::_Move, this);
+    }
+    else if (__h) {
+        this->__call(_Action::_Move, &__rhs);
+    }
+    else if (__rhs.__h) {
+        __rhs.__call(_Action::_Move, this);
+    }
+}
+
+// 6.4 Non-member functions
+
+inline _LIBCPP_INLINE_VISIBILITY
+void swap(any & __lhs, any & __rhs) _NOEXCEPT
+{
+    __lhs.swap(__rhs);
+}
+
+template <class _Tp, class ..._Args>
+inline _LIBCPP_INLINE_VISIBILITY
+any make_any(_Args&&... __args) {
+    return any(in_place_type<_Tp>, _VSTD::forward<_Args>(__args)...);
+}
+
+template <class _Tp, class _Up, class ..._Args>
+inline _LIBCPP_INLINE_VISIBILITY
+any make_any(initializer_list<_Up> __il, _Args&&... __args) {
+    return any(in_place_type<_Tp>, __il, _VSTD::forward<_Args>(__args)...);
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
+_ValueType any_cast(any const & __v)
+{
+    using _RawValueType = __uncvref_t<_ValueType>;
+    static_assert(is_constructible<_ValueType, _RawValueType const &>::value,
+                  "ValueType is required to be a const lvalue reference "
+                  "or a CopyConstructible type");
+    auto __tmp = _VSTD::any_cast<add_const_t<_RawValueType>>(&__v);
+    if (__tmp == nullptr)
+        __throw_bad_any_cast();
+    return static_cast<_ValueType>(*__tmp);
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
+_ValueType any_cast(any & __v)
+{
+    using _RawValueType = __uncvref_t<_ValueType>;
+    static_assert(is_constructible<_ValueType, _RawValueType &>::value,
+                  "ValueType is required to be an lvalue reference "
+                  "or a CopyConstructible type");
+    auto __tmp = _VSTD::any_cast<_RawValueType>(&__v);
+    if (__tmp == nullptr)
+        __throw_bad_any_cast();
+    return static_cast<_ValueType>(*__tmp);
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_ANY_CAST
+_ValueType any_cast(any && __v)
+{
+    using _RawValueType = __uncvref_t<_ValueType>;
+    static_assert(is_constructible<_ValueType, _RawValueType>::value,
+                  "ValueType is required to be an rvalue reference "
+                  "or a CopyConstructible type");
+    auto __tmp = _VSTD::any_cast<_RawValueType>(&__v);
+    if (__tmp == nullptr)
+        __throw_bad_any_cast();
+    return static_cast<_ValueType>(_VSTD::move(*__tmp));
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+add_pointer_t<add_const_t<_ValueType>>
+any_cast(any const * __any) _NOEXCEPT
+{
+    static_assert(!is_reference<_ValueType>::value,
+                  "_ValueType may not be a reference.");
+    return _VSTD::any_cast<_ValueType>(const_cast<any *>(__any));
+}
+
+template <class _RetType>
+inline _LIBCPP_INLINE_VISIBILITY
+_RetType __pointer_or_func_cast(void* __p, /*IsFunction*/false_type) noexcept {
+  return static_cast<_RetType>(__p);
+}
+
+template <class _RetType>
+inline _LIBCPP_INLINE_VISIBILITY
+_RetType __pointer_or_func_cast(void*, /*IsFunction*/true_type) noexcept {
+  return nullptr;
+}
+
+template <class _ValueType>
+add_pointer_t<_ValueType>
+any_cast(any * __any) _NOEXCEPT
+{
+    using __any_imp::_Action;
+    static_assert(!is_reference<_ValueType>::value,
+                  "_ValueType may not be a reference.");
+    typedef typename add_pointer<_ValueType>::type _ReturnType;
+    if (__any && __any->__h) {
+      void *__p = __any->__call(_Action::_Get, nullptr,
+#if !defined(_LIBCPP_NO_RTTI)
+                          &typeid(_ValueType),
+#else
+                          nullptr,
+#endif
+                          __any_imp::__get_fallback_typeid<_ValueType>());
+        return _VSTD::__pointer_or_func_cast<_ReturnType>(
+            __p, is_function<_ValueType>{});
+    }
+    return nullptr;
+}
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_ANY
diff --git a/contrib/libs/cxxsupp/libcxx/include/array b/contrib/libs/cxxsupp/libcxx/include/array
new file mode 100644
index 00000000000..0ddfc955af9
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/array
@@ -0,0 +1,520 @@
+// -*- C++ -*-
+//===---------------------------- array -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_ARRAY
+#define _LIBCPP_ARRAY
+
+/*
+    array synopsis
+
+namespace std
+{
+template <class T, size_t N >
+struct array
+{
+    // types:
+    typedef T & reference;
+    typedef const T & const_reference;
+    typedef implementation defined iterator;
+    typedef implementation defined const_iterator;
+    typedef size_t size_type;
+    typedef ptrdiff_t difference_type;
+    typedef T value_type;
+    typedef T* pointer;
+    typedef const T* const_pointer;
+    typedef std::reverse_iterator<iterator> reverse_iterator;
+    typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+
+    // No explicit construct/copy/destroy for aggregate type
+    void fill(const T& u);                                      // constexpr in C++20
+    void swap(array& a) noexcept(is_nothrow_swappable_v<T>);    // constexpr in C++20
+
+    // iterators:
+    iterator begin() noexcept;                                  // constexpr in C++17
+    const_iterator begin() const noexcept;                      // constexpr in C++17
+    iterator end() noexcept;                                    // constexpr in C++17
+    const_iterator end() const noexcept;                        // constexpr in C++17
+
+    reverse_iterator rbegin() noexcept;                         // constexpr in C++17
+    const_reverse_iterator rbegin() const noexcept;             // constexpr in C++17
+    reverse_iterator rend() noexcept;                           // constexpr in C++17
+    const_reverse_iterator rend() const noexcept;               // constexpr in C++17
+
+    const_iterator cbegin() const noexcept;                     // constexpr in C++17
+    const_iterator cend() const noexcept;                       // constexpr in C++17
+    const_reverse_iterator crbegin() const noexcept;            // constexpr in C++17
+    const_reverse_iterator crend() const noexcept;              // constexpr in C++17
+
+    // capacity:
+    constexpr size_type size() const noexcept;
+    constexpr size_type max_size() const noexcept;
+    constexpr bool empty() const noexcept;
+
+    // element access:
+    reference operator[](size_type n);                          // constexpr in C++17
+    const_reference operator[](size_type n) const;              // constexpr in C++14
+    reference at(size_type n);                                  // constexpr in C++17
+    const_reference at(size_type n) const;                      // constexpr in C++14
+
+    reference front();                                          // constexpr in C++17
+    const_reference front() const;                              // constexpr in C++14
+    reference back();                                           // constexpr in C++17
+    const_reference back() const;                               // constexpr in C++14
+
+    T* data() noexcept;                                         // constexpr in C++17
+    const T* data() const noexcept;                             // constexpr in C++17
+};
+
+template <class T, class... U>
+  array(T, U...) -> array<T, 1 + sizeof...(U)>;                 // C++17
+
+template <class T, size_t N>
+  bool operator==(const array<T,N>& x, const array<T,N>& y);    // constexpr in C++20
+template <class T, size_t N>
+  bool operator!=(const array<T,N>& x, const array<T,N>& y);    // constexpr in C++20
+template <class T, size_t N>
+  bool operator<(const array<T,N>& x, const array<T,N>& y);     // constexpr in C++20
+template <class T, size_t N>
+  bool operator>(const array<T,N>& x, const array<T,N>& y);     // constexpr in C++20
+template <class T, size_t N>
+  bool operator<=(const array<T,N>& x, const array<T,N>& y);    // constexpr in C++20
+template <class T, size_t N>
+  bool operator>=(const array<T,N>& x, const array<T,N>& y);    // constexpr in C++20
+
+template <class T, size_t N >
+  void swap(array<T,N>& x, array<T,N>& y) noexcept(noexcept(x.swap(y))); // constexpr in C++20
+
+template <class T, size_t N>
+  constexpr array<remove_cv_t<T>, N> to_array(T (&a)[N]);  // C++20
+template <class T, size_t N>
+  constexpr array<remove_cv_t<T>, N> to_array(T (&&a)[N]); // C++20
+
+template <class T> struct tuple_size;
+template <size_t I, class T> struct tuple_element;
+template <class T, size_t N> struct tuple_size<array<T, N>>;
+template <size_t I, class T, size_t N> struct tuple_element<I, array<T, N>>;
+template <size_t I, class T, size_t N> T& get(array<T, N>&) noexcept;               // constexpr in C++14
+template <size_t I, class T, size_t N> const T& get(const array<T, N>&) noexcept;   // constexpr in C++14
+template <size_t I, class T, size_t N> T&& get(array<T, N>&&) noexcept;             // constexpr in C++14
+template <size_t I, class T, size_t N> const T&& get(const array<T, N>&&) noexcept; // constexpr in C++14
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__tuple>
+#include <algorithm>
+#include <cstdlib> // for _LIBCPP_UNREACHABLE
+#include <iterator>
+#include <stdexcept>
+#include <type_traits>
+#include <utility>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, size_t _Size>
+struct _LIBCPP_TEMPLATE_VIS array
+{
+    // types:
+    typedef array __self;
+    typedef _Tp                                   value_type;
+    typedef value_type&                           reference;
+    typedef const value_type&                     const_reference;
+    typedef value_type*                           iterator;
+    typedef const value_type*                     const_iterator;
+    typedef value_type*                           pointer;
+    typedef const value_type*                     const_pointer;
+    typedef size_t                                size_type;
+    typedef ptrdiff_t                             difference_type;
+    typedef _VSTD::reverse_iterator<iterator>       reverse_iterator;
+    typedef _VSTD::reverse_iterator<const_iterator> const_reverse_iterator;
+
+    _Tp __elems_[_Size];
+
+    // No explicit construct/copy/destroy for aggregate type
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    void fill(const value_type& __u) {
+        _VSTD::fill_n(data(), _Size, __u);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    void swap(array& __a) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value) {
+        _VSTD::swap_ranges(data(), data() + _Size, __a.data());
+    }
+
+    // iterators:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    iterator begin() _NOEXCEPT {return iterator(data());}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_iterator begin() const _NOEXCEPT {return const_iterator(data());}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    iterator end() _NOEXCEPT {return iterator(data() + _Size);}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_iterator end() const _NOEXCEPT {return const_iterator(data() + _Size);}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator rbegin() _NOEXCEPT {return reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_reverse_iterator rbegin() const _NOEXCEPT {return const_reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator rend() _NOEXCEPT {return reverse_iterator(begin());}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_reverse_iterator rend() const _NOEXCEPT {return const_reverse_iterator(begin());}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_iterator cbegin() const _NOEXCEPT {return begin();}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_iterator cend() const _NOEXCEPT {return end();}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_reverse_iterator crbegin() const _NOEXCEPT {return rbegin();}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_reverse_iterator crend() const _NOEXCEPT {return rend();}
+
+    // capacity:
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR size_type size() const _NOEXCEPT {return _Size;}
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR size_type max_size() const _NOEXCEPT {return _Size;}
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT {return _Size == 0;}
+
+    // element access:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reference operator[](size_type __n) _NOEXCEPT {
+        _LIBCPP_ASSERT(__n < _Size, "out-of-bounds access in std::array<T, N>");
+        return __elems_[__n];
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const_reference operator[](size_type __n) const _NOEXCEPT {
+        _LIBCPP_ASSERT(__n < _Size, "out-of-bounds access in std::array<T, N>");
+        return __elems_[__n];
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX14 reference at(size_type __n)
+    {
+        if (__n >= _Size)
+            __throw_out_of_range("array::at");
+        return __elems_[__n];
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference at(size_type __n) const
+    {
+        if (__n >= _Size)
+            __throw_out_of_range("array::at");
+        return __elems_[__n];
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 reference front()             _NOEXCEPT {return (*this)[0];}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference front() const _NOEXCEPT {return (*this)[0];}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 reference back()              _NOEXCEPT {return (*this)[_Size - 1];}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const_reference back() const  _NOEXCEPT {return (*this)[_Size - 1];}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    value_type* data() _NOEXCEPT {return __elems_;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const value_type* data() const _NOEXCEPT {return __elems_;}
+};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS array<_Tp, 0>
+{
+    // types:
+    typedef array __self;
+    typedef _Tp                                   value_type;
+    typedef value_type&                           reference;
+    typedef const value_type&                     const_reference;
+    typedef value_type*                           iterator;
+    typedef const value_type*                     const_iterator;
+    typedef value_type*                           pointer;
+    typedef const value_type*                     const_pointer;
+    typedef size_t                                size_type;
+    typedef ptrdiff_t                             difference_type;
+    typedef _VSTD::reverse_iterator<iterator>       reverse_iterator;
+    typedef _VSTD::reverse_iterator<const_iterator> const_reverse_iterator;
+
+    typedef typename conditional<is_const<_Tp>::value, const char,
+                                char>::type _CharType;
+
+    struct  _ArrayInStructT { _Tp __data_[1]; };
+    _ALIGNAS_TYPE(_ArrayInStructT) _CharType __elems_[sizeof(_ArrayInStructT)];
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    value_type* data() _NOEXCEPT {return nullptr;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const value_type* data() const _NOEXCEPT {return nullptr;}
+
+    // No explicit construct/copy/destroy for aggregate type
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    void fill(const value_type&) {
+      static_assert(!is_const<_Tp>::value,
+                    "cannot fill zero-sized array of type 'const T'");
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    void swap(array&) _NOEXCEPT {
+      static_assert(!is_const<_Tp>::value,
+                    "cannot swap zero-sized array of type 'const T'");
+    }
+
+    // iterators:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    iterator begin() _NOEXCEPT {return iterator(data());}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_iterator begin() const _NOEXCEPT {return const_iterator(data());}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    iterator end() _NOEXCEPT {return iterator(data());}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_iterator end() const _NOEXCEPT {return const_iterator(data());}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator rbegin() _NOEXCEPT {return reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_reverse_iterator rbegin() const _NOEXCEPT {return const_reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reverse_iterator rend() _NOEXCEPT {return reverse_iterator(begin());}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_reverse_iterator rend() const _NOEXCEPT {return const_reverse_iterator(begin());}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_iterator cbegin() const _NOEXCEPT {return begin();}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_iterator cend() const _NOEXCEPT {return end();}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_reverse_iterator crbegin() const _NOEXCEPT {return rbegin();}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    const_reverse_iterator crend() const _NOEXCEPT {return rend();}
+
+    // capacity:
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR size_type size() const _NOEXCEPT {return 0; }
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR size_type max_size() const _NOEXCEPT {return 0;}
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT {return true;}
+
+    // element access:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reference operator[](size_type) _NOEXCEPT {
+      _LIBCPP_ASSERT(false, "cannot call array<T, 0>::operator[] on a zero-sized array");
+      _LIBCPP_UNREACHABLE();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const_reference operator[](size_type) const _NOEXCEPT {
+      _LIBCPP_ASSERT(false, "cannot call array<T, 0>::operator[] on a zero-sized array");
+      _LIBCPP_UNREACHABLE();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reference at(size_type) {
+      __throw_out_of_range("array<T, 0>::at");
+      _LIBCPP_UNREACHABLE();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const_reference at(size_type) const {
+      __throw_out_of_range("array<T, 0>::at");
+      _LIBCPP_UNREACHABLE();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reference front() _NOEXCEPT {
+      _LIBCPP_ASSERT(false, "cannot call array<T, 0>::front() on a zero-sized array");
+      _LIBCPP_UNREACHABLE();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const_reference front() const _NOEXCEPT {
+      _LIBCPP_ASSERT(false, "cannot call array<T, 0>::front() on a zero-sized array");
+      _LIBCPP_UNREACHABLE();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
+    reference back() _NOEXCEPT {
+      _LIBCPP_ASSERT(false, "cannot call array<T, 0>::back() on a zero-sized array");
+      _LIBCPP_UNREACHABLE();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const_reference back() const _NOEXCEPT {
+      _LIBCPP_ASSERT(false, "cannot call array<T, 0>::back() on a zero-sized array");
+      _LIBCPP_UNREACHABLE();
+    }
+};
+
+
+#if _LIBCPP_STD_VER >= 17
+template<class _Tp, class... _Args,
+         class = enable_if_t<__all<_IsSame<_Tp, _Args>::value...>::value>
+         >
+array(_Tp, _Args...)
+  -> array<_Tp, 1 + sizeof...(_Args)>;
+#endif
+
+template <class _Tp, size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+operator==(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
+{
+    return _VSTD::equal(__x.begin(), __x.end(), __y.begin());
+}
+
+template <class _Tp, size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+operator!=(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Tp, size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+operator<(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
+{
+    return _VSTD::lexicographical_compare(__x.begin(), __x.end(),
+                                          __y.begin(), __y.end());
+}
+
+template <class _Tp, size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+operator>(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
+{
+    return __y < __x;
+}
+
+template <class _Tp, size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+operator<=(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _Tp, size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+operator>=(const array<_Tp, _Size>& __x, const array<_Tp, _Size>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _Tp, size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+typename enable_if
+<
+    _Size == 0 ||
+    __is_swappable<_Tp>::value,
+    void
+>::type
+swap(array<_Tp, _Size>& __x, array<_Tp, _Size>& __y)
+                                  _NOEXCEPT_(noexcept(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+template <class _Tp, size_t _Size>
+struct _LIBCPP_TEMPLATE_VIS tuple_size<array<_Tp, _Size> >
+    : public integral_constant<size_t, _Size> {};
+
+template <size_t _Ip, class _Tp, size_t _Size>
+struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, array<_Tp, _Size> >
+{
+    static_assert(_Ip < _Size, "Index out of bounds in std::tuple_element<> (std::array)");
+    typedef _Tp type;
+};
+
+template <size_t _Ip, class _Tp, size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp&
+get(array<_Tp, _Size>& __a) _NOEXCEPT
+{
+    static_assert(_Ip < _Size, "Index out of bounds in std::get<> (std::array)");
+    return __a.__elems_[_Ip];
+}
+
+template <size_t _Ip, class _Tp, size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const _Tp&
+get(const array<_Tp, _Size>& __a) _NOEXCEPT
+{
+    static_assert(_Ip < _Size, "Index out of bounds in std::get<> (const std::array)");
+    return __a.__elems_[_Ip];
+}
+
+template <size_t _Ip, class _Tp, size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp&&
+get(array<_Tp, _Size>&& __a) _NOEXCEPT
+{
+    static_assert(_Ip < _Size, "Index out of bounds in std::get<> (std::array &&)");
+    return _VSTD::move(__a.__elems_[_Ip]);
+}
+
+template <size_t _Ip, class _Tp, size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const _Tp&&
+get(const array<_Tp, _Size>&& __a) _NOEXCEPT
+{
+    static_assert(_Ip < _Size, "Index out of bounds in std::get<> (const std::array &&)");
+    return _VSTD::move(__a.__elems_[_Ip]);
+}
+
+#if _LIBCPP_STD_VER > 17
+
+template <typename _Tp, size_t _Size, size_t... _Index>
+_LIBCPP_INLINE_VISIBILITY constexpr array<remove_cv_t<_Tp>, _Size>
+__to_array_lvalue_impl(_Tp (&__arr)[_Size], index_sequence<_Index...>) {
+  return {{__arr[_Index]...}};
+}
+
+template <typename _Tp, size_t _Size, size_t... _Index>
+_LIBCPP_INLINE_VISIBILITY constexpr array<remove_cv_t<_Tp>, _Size>
+__to_array_rvalue_impl(_Tp(&&__arr)[_Size], index_sequence<_Index...>) {
+  return {{_VSTD::move(__arr[_Index])...}};
+}
+
+template <typename _Tp, size_t _Size>
+_LIBCPP_INLINE_VISIBILITY constexpr array<remove_cv_t<_Tp>, _Size>
+to_array(_Tp (&__arr)[_Size]) noexcept(is_nothrow_constructible_v<_Tp, _Tp&>) {
+  static_assert(
+      !is_array_v<_Tp>,
+      "[array.creation]/1: to_array does not accept multidimensional arrays.");
+  static_assert(
+      is_constructible_v<_Tp, _Tp&>,
+      "[array.creation]/1: to_array requires copy constructible elements.");
+  return _VSTD::__to_array_lvalue_impl(__arr, make_index_sequence<_Size>());
+}
+
+template <typename _Tp, size_t _Size>
+_LIBCPP_INLINE_VISIBILITY constexpr array<remove_cv_t<_Tp>, _Size>
+to_array(_Tp(&&__arr)[_Size]) noexcept(is_nothrow_move_constructible_v<_Tp>) {
+  static_assert(
+      !is_array_v<_Tp>,
+      "[array.creation]/4: to_array does not accept multidimensional arrays.");
+  static_assert(
+      is_move_constructible_v<_Tp>,
+      "[array.creation]/4: to_array requires move constructible elements.");
+  return _VSTD::__to_array_rvalue_impl(_VSTD::move(__arr),
+                                       make_index_sequence<_Size>());
+}
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_ARRAY
diff --git a/contrib/libs/cxxsupp/libcxx/include/atomic b/contrib/libs/cxxsupp/libcxx/include/atomic
new file mode 100644
index 00000000000..992c7459618
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/atomic
@@ -0,0 +1,2723 @@
+// -*- C++ -*-
+//===--------------------------- atomic -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_ATOMIC
+#define _LIBCPP_ATOMIC
+
+/*
+    atomic synopsis
+
+namespace std
+{
+
+// feature test macro [version.syn]
+
+#define __cpp_lib_atomic_is_always_lock_free
+#define __cpp_lib_atomic_flag_test
+#define __cpp_lib_atomic_lock_free_type_aliases
+#define __cpp_lib_atomic_wait
+
+ // order and consistency
+
+ enum memory_order: unspecified // enum class in C++20
+ {
+    relaxed,
+    consume, // load-consume
+    acquire, // load-acquire
+    release, // store-release
+    acq_rel, // store-release load-acquire
+    seq_cst // store-release load-acquire
+ };
+
+ inline constexpr auto memory_order_relaxed = memory_order::relaxed;
+ inline constexpr auto memory_order_consume = memory_order::consume;
+ inline constexpr auto memory_order_acquire = memory_order::acquire;
+ inline constexpr auto memory_order_release = memory_order::release;
+ inline constexpr auto memory_order_acq_rel = memory_order::acq_rel;
+ inline constexpr auto memory_order_seq_cst = memory_order::seq_cst;
+
+template <class T> T kill_dependency(T y) noexcept;
+
+// lock-free property
+
+#define ATOMIC_BOOL_LOCK_FREE unspecified
+#define ATOMIC_CHAR_LOCK_FREE unspecified
+#define ATOMIC_CHAR8_T_LOCK_FREE unspecified // C++20
+#define ATOMIC_CHAR16_T_LOCK_FREE unspecified
+#define ATOMIC_CHAR32_T_LOCK_FREE unspecified
+#define ATOMIC_WCHAR_T_LOCK_FREE unspecified
+#define ATOMIC_SHORT_LOCK_FREE unspecified
+#define ATOMIC_INT_LOCK_FREE unspecified
+#define ATOMIC_LONG_LOCK_FREE unspecified
+#define ATOMIC_LLONG_LOCK_FREE unspecified
+#define ATOMIC_POINTER_LOCK_FREE unspecified
+
+template <class T>
+struct atomic
+{
+    using value_type = T;
+
+    static constexpr bool is_always_lock_free;
+    bool is_lock_free() const volatile noexcept;
+    bool is_lock_free() const noexcept;
+
+    atomic() noexcept = default; // until C++20
+    constexpr atomic() noexcept(is_nothrow_default_constructible_v<T>); // since C++20
+    constexpr atomic(T desr) noexcept;
+    atomic(const atomic&) = delete;
+    atomic& operator=(const atomic&) = delete;
+    atomic& operator=(const atomic&) volatile = delete;
+
+    T load(memory_order m = memory_order_seq_cst) const volatile noexcept;
+    T load(memory_order m = memory_order_seq_cst) const noexcept;
+    operator T() const volatile noexcept;
+    operator T() const noexcept;
+    void store(T desr, memory_order m = memory_order_seq_cst) volatile noexcept;
+    void store(T desr, memory_order m = memory_order_seq_cst) noexcept;
+    T operator=(T) volatile noexcept;
+    T operator=(T) noexcept;
+
+    T exchange(T desr, memory_order m = memory_order_seq_cst) volatile noexcept;
+    T exchange(T desr, memory_order m = memory_order_seq_cst) noexcept;
+    bool compare_exchange_weak(T& expc, T desr,
+                               memory_order s, memory_order f) volatile noexcept;
+    bool compare_exchange_weak(T& expc, T desr, memory_order s, memory_order f) noexcept;
+    bool compare_exchange_strong(T& expc, T desr,
+                                 memory_order s, memory_order f) volatile noexcept;
+    bool compare_exchange_strong(T& expc, T desr,
+                                 memory_order s, memory_order f) noexcept;
+    bool compare_exchange_weak(T& expc, T desr,
+                               memory_order m = memory_order_seq_cst) volatile noexcept;
+    bool compare_exchange_weak(T& expc, T desr,
+                               memory_order m = memory_order_seq_cst) noexcept;
+    bool compare_exchange_strong(T& expc, T desr,
+                                memory_order m = memory_order_seq_cst) volatile noexcept;
+    bool compare_exchange_strong(T& expc, T desr,
+                                 memory_order m = memory_order_seq_cst) noexcept;
+
+    void wait(T, memory_order = memory_order::seq_cst) const volatile noexcept;
+    void wait(T, memory_order = memory_order::seq_cst) const noexcept;
+    void notify_one() volatile noexcept;
+    void notify_one() noexcept;
+    void notify_all() volatile noexcept;
+    void notify_all() noexcept;
+};
+
+template <>
+struct atomic<integral>
+{
+    using value_type = integral;
+    using difference_type = value_type;
+
+    static constexpr bool is_always_lock_free;
+    bool is_lock_free() const volatile noexcept;
+    bool is_lock_free() const noexcept;
+
+    atomic() noexcept = default;
+    constexpr atomic(integral desr) noexcept;
+    atomic(const atomic&) = delete;
+    atomic& operator=(const atomic&) = delete;
+    atomic& operator=(const atomic&) volatile = delete;
+
+    integral load(memory_order m = memory_order_seq_cst) const volatile noexcept;
+    integral load(memory_order m = memory_order_seq_cst) const noexcept;
+    operator integral() const volatile noexcept;
+    operator integral() const noexcept;
+    void store(integral desr, memory_order m = memory_order_seq_cst) volatile noexcept;
+    void store(integral desr, memory_order m = memory_order_seq_cst) noexcept;
+    integral operator=(integral desr) volatile noexcept;
+    integral operator=(integral desr) noexcept;
+
+    integral exchange(integral desr,
+                      memory_order m = memory_order_seq_cst) volatile noexcept;
+    integral exchange(integral desr, memory_order m = memory_order_seq_cst) noexcept;
+    bool compare_exchange_weak(integral& expc, integral desr,
+                               memory_order s, memory_order f) volatile noexcept;
+    bool compare_exchange_weak(integral& expc, integral desr,
+                               memory_order s, memory_order f) noexcept;
+    bool compare_exchange_strong(integral& expc, integral desr,
+                                 memory_order s, memory_order f) volatile noexcept;
+    bool compare_exchange_strong(integral& expc, integral desr,
+                                 memory_order s, memory_order f) noexcept;
+    bool compare_exchange_weak(integral& expc, integral desr,
+                               memory_order m = memory_order_seq_cst) volatile noexcept;
+    bool compare_exchange_weak(integral& expc, integral desr,
+                               memory_order m = memory_order_seq_cst) noexcept;
+    bool compare_exchange_strong(integral& expc, integral desr,
+                                memory_order m = memory_order_seq_cst) volatile noexcept;
+    bool compare_exchange_strong(integral& expc, integral desr,
+                                 memory_order m = memory_order_seq_cst) noexcept;
+
+    integral fetch_add(integral op, memory_order m = memory_order_seq_cst) volatile noexcept;
+    integral fetch_add(integral op, memory_order m = memory_order_seq_cst) noexcept;
+    integral fetch_sub(integral op, memory_order m = memory_order_seq_cst) volatile noexcept;
+    integral fetch_sub(integral op, memory_order m = memory_order_seq_cst) noexcept;
+    integral fetch_and(integral op, memory_order m = memory_order_seq_cst) volatile noexcept;
+    integral fetch_and(integral op, memory_order m = memory_order_seq_cst) noexcept;
+    integral fetch_or(integral op, memory_order m = memory_order_seq_cst) volatile noexcept;
+    integral fetch_or(integral op, memory_order m = memory_order_seq_cst) noexcept;
+    integral fetch_xor(integral op, memory_order m = memory_order_seq_cst) volatile noexcept;
+    integral fetch_xor(integral op, memory_order m = memory_order_seq_cst) noexcept;
+
+    integral operator++(int) volatile noexcept;
+    integral operator++(int) noexcept;
+    integral operator--(int) volatile noexcept;
+    integral operator--(int) noexcept;
+    integral operator++() volatile noexcept;
+    integral operator++() noexcept;
+    integral operator--() volatile noexcept;
+    integral operator--() noexcept;
+    integral operator+=(integral op) volatile noexcept;
+    integral operator+=(integral op) noexcept;
+    integral operator-=(integral op) volatile noexcept;
+    integral operator-=(integral op) noexcept;
+    integral operator&=(integral op) volatile noexcept;
+    integral operator&=(integral op) noexcept;
+    integral operator|=(integral op) volatile noexcept;
+    integral operator|=(integral op) noexcept;
+    integral operator^=(integral op) volatile noexcept;
+    integral operator^=(integral op) noexcept;
+
+    void wait(integral, memory_order = memory_order::seq_cst) const volatile noexcept;
+    void wait(integral, memory_order = memory_order::seq_cst) const noexcept;
+    void notify_one() volatile noexcept;
+    void notify_one() noexcept;
+    void notify_all() volatile noexcept;
+    void notify_all() noexcept;
+};
+
+template <class T>
+struct atomic<T*>
+{
+    using value_type = T*;
+    using difference_type = ptrdiff_t;
+
+    static constexpr bool is_always_lock_free;
+    bool is_lock_free() const volatile noexcept;
+    bool is_lock_free() const noexcept;
+
+    atomic() noexcept = default; // until C++20
+    constexpr atomic() noexcept; // since C++20
+    constexpr atomic(T* desr) noexcept;
+    atomic(const atomic&) = delete;
+    atomic& operator=(const atomic&) = delete;
+    atomic& operator=(const atomic&) volatile = delete;
+
+    T* load(memory_order m = memory_order_seq_cst) const volatile noexcept;
+    T* load(memory_order m = memory_order_seq_cst) const noexcept;
+    operator T*() const volatile noexcept;
+    operator T*() const noexcept;
+    void store(T* desr, memory_order m = memory_order_seq_cst) volatile noexcept;
+    void store(T* desr, memory_order m = memory_order_seq_cst) noexcept;
+    T* operator=(T*) volatile noexcept;
+    T* operator=(T*) noexcept;
+
+    T* exchange(T* desr, memory_order m = memory_order_seq_cst) volatile noexcept;
+    T* exchange(T* desr, memory_order m = memory_order_seq_cst) noexcept;
+    bool compare_exchange_weak(T*& expc, T* desr,
+                               memory_order s, memory_order f) volatile noexcept;
+    bool compare_exchange_weak(T*& expc, T* desr,
+                               memory_order s, memory_order f) noexcept;
+    bool compare_exchange_strong(T*& expc, T* desr,
+                                 memory_order s, memory_order f) volatile noexcept;
+    bool compare_exchange_strong(T*& expc, T* desr,
+                                 memory_order s, memory_order f) noexcept;
+    bool compare_exchange_weak(T*& expc, T* desr,
+                               memory_order m = memory_order_seq_cst) volatile noexcept;
+    bool compare_exchange_weak(T*& expc, T* desr,
+                               memory_order m = memory_order_seq_cst) noexcept;
+    bool compare_exchange_strong(T*& expc, T* desr,
+                                memory_order m = memory_order_seq_cst) volatile noexcept;
+    bool compare_exchange_strong(T*& expc, T* desr,
+                                 memory_order m = memory_order_seq_cst) noexcept;
+    T* fetch_add(ptrdiff_t op, memory_order m = memory_order_seq_cst) volatile noexcept;
+    T* fetch_add(ptrdiff_t op, memory_order m = memory_order_seq_cst) noexcept;
+    T* fetch_sub(ptrdiff_t op, memory_order m = memory_order_seq_cst) volatile noexcept;
+    T* fetch_sub(ptrdiff_t op, memory_order m = memory_order_seq_cst) noexcept;
+
+    T* operator++(int) volatile noexcept;
+    T* operator++(int) noexcept;
+    T* operator--(int) volatile noexcept;
+    T* operator--(int) noexcept;
+    T* operator++() volatile noexcept;
+    T* operator++() noexcept;
+    T* operator--() volatile noexcept;
+    T* operator--() noexcept;
+    T* operator+=(ptrdiff_t op) volatile noexcept;
+    T* operator+=(ptrdiff_t op) noexcept;
+    T* operator-=(ptrdiff_t op) volatile noexcept;
+    T* operator-=(ptrdiff_t op) noexcept;
+
+    void wait(T*, memory_order = memory_order::seq_cst) const volatile noexcept;
+    void wait(T*, memory_order = memory_order::seq_cst) const noexcept;
+    void notify_one() volatile noexcept;
+    void notify_one() noexcept;
+    void notify_all() volatile noexcept;
+    void notify_all() noexcept;
+};
+
+
+// [atomics.nonmembers], non-member functions
+template<class T>
+  bool atomic_is_lock_free(const volatile atomic<T>*) noexcept;
+template<class T>
+  bool atomic_is_lock_free(const atomic<T>*) noexcept;
+template<class T>
+  void atomic_store(volatile atomic<T>*, atomic<T>::value_type) noexcept;
+template<class T>
+  void atomic_store(atomic<T>*, atomic<T>::value_type) noexcept;
+template<class T>
+  void atomic_store_explicit(volatile atomic<T>*, atomic<T>::value_type,
+                             memory_order) noexcept;
+template<class T>
+  void atomic_store_explicit(atomic<T>*, atomic<T>::value_type,
+                             memory_order) noexcept;
+template<class T>
+  T atomic_load(const volatile atomic<T>*) noexcept;
+template<class T>
+  T atomic_load(const atomic<T>*) noexcept;
+template<class T>
+  T atomic_load_explicit(const volatile atomic<T>*, memory_order) noexcept;
+template<class T>
+  T atomic_load_explicit(const atomic<T>*, memory_order) noexcept;
+template<class T>
+  T atomic_exchange(volatile atomic<T>*, atomic<T>::value_type) noexcept;
+template<class T>
+  T atomic_exchange(atomic<T>*, atomic<T>::value_type) noexcept;
+template<class T>
+  T atomic_exchange_explicit(volatile atomic<T>*, atomic<T>::value_type,
+                             memory_order) noexcept;
+template<class T>
+  T atomic_exchange_explicit(atomic<T>*, atomic<T>::value_type,
+                             memory_order) noexcept;
+template<class T>
+  bool atomic_compare_exchange_weak(volatile atomic<T>*, atomic<T>::value_type*,
+                                    atomic<T>::value_type) noexcept;
+template<class T>
+  bool atomic_compare_exchange_weak(atomic<T>*, atomic<T>::value_type*,
+                                    atomic<T>::value_type) noexcept;
+template<class T>
+  bool atomic_compare_exchange_strong(volatile atomic<T>*, atomic<T>::value_type*,
+                                      atomic<T>::value_type) noexcept;
+template<class T>
+  bool atomic_compare_exchange_strong(atomic<T>*, atomic<T>::value_type*,
+                                      atomic<T>::value_type) noexcept;
+template<class T>
+  bool atomic_compare_exchange_weak_explicit(volatile atomic<T>*, atomic<T>::value_type*,
+                                             atomic<T>::value_type,
+                                             memory_order, memory_order) noexcept;
+template<class T>
+  bool atomic_compare_exchange_weak_explicit(atomic<T>*, atomic<T>::value_type*,
+                                             atomic<T>::value_type,
+                                             memory_order, memory_order) noexcept;
+template<class T>
+  bool atomic_compare_exchange_strong_explicit(volatile atomic<T>*, atomic<T>::value_type*,
+                                               atomic<T>::value_type,
+                                               memory_order, memory_order) noexcept;
+template<class T>
+  bool atomic_compare_exchange_strong_explicit(atomic<T>*, atomic<T>::value_type*,
+                                               atomic<T>::value_type,
+                                               memory_order, memory_order) noexcept;
+
+template<class T>
+  T atomic_fetch_add(volatile atomic<T>*, atomic<T>::difference_type) noexcept;
+template<class T>
+  T atomic_fetch_add(atomic<T>*, atomic<T>::difference_type) noexcept;
+template<class T>
+  T atomic_fetch_add_explicit(volatile atomic<T>*, atomic<T>::difference_type,
+                              memory_order) noexcept;
+template<class T>
+  T atomic_fetch_add_explicit(atomic<T>*, atomic<T>::difference_type,
+                              memory_order) noexcept;
+template<class T>
+  T atomic_fetch_sub(volatile atomic<T>*, atomic<T>::difference_type) noexcept;
+template<class T>
+  T atomic_fetch_sub(atomic<T>*, atomic<T>::difference_type) noexcept;
+template<class T>
+  T atomic_fetch_sub_explicit(volatile atomic<T>*, atomic<T>::difference_type,
+                              memory_order) noexcept;
+template<class T>
+  T atomic_fetch_sub_explicit(atomic<T>*, atomic<T>::difference_type,
+                              memory_order) noexcept;
+template<class T>
+  T atomic_fetch_and(volatile atomic<T>*, atomic<T>::value_type) noexcept;
+template<class T>
+  T atomic_fetch_and(atomic<T>*, atomic<T>::value_type) noexcept;
+template<class T>
+  T atomic_fetch_and_explicit(volatile atomic<T>*, atomic<T>::value_type,
+                              memory_order) noexcept;
+template<class T>
+  T atomic_fetch_and_explicit(atomic<T>*, atomic<T>::value_type,
+                              memory_order) noexcept;
+template<class T>
+  T atomic_fetch_or(volatile atomic<T>*, atomic<T>::value_type) noexcept;
+template<class T>
+  T atomic_fetch_or(atomic<T>*, atomic<T>::value_type) noexcept;
+template<class T>
+  T atomic_fetch_or_explicit(volatile atomic<T>*, atomic<T>::value_type,
+                             memory_order) noexcept;
+template<class T>
+  T atomic_fetch_or_explicit(atomic<T>*, atomic<T>::value_type,
+                             memory_order) noexcept;
+template<class T>
+  T atomic_fetch_xor(volatile atomic<T>*, atomic<T>::value_type) noexcept;
+template<class T>
+  T atomic_fetch_xor(atomic<T>*, atomic<T>::value_type) noexcept;
+template<class T>
+  T atomic_fetch_xor_explicit(volatile atomic<T>*, atomic<T>::value_type,
+                              memory_order) noexcept;
+template<class T>
+  T atomic_fetch_xor_explicit(atomic<T>*, atomic<T>::value_type,
+                              memory_order) noexcept;
+
+template<class T>
+  void atomic_wait(const volatile atomic<T>*, atomic<T>::value_type);
+template<class T>
+  void atomic_wait(const atomic<T>*, atomic<T>::value_type);
+template<class T>
+  void atomic_wait_explicit(const volatile atomic<T>*, atomic<T>::value_type,
+                            memory_order);
+template<class T>
+  void atomic_wait_explicit(const atomic<T>*, atomic<T>::value_type,
+                            memory_order);
+template<class T>
+  void atomic_notify_one(volatile atomic<T>*);
+template<class T>
+  void atomic_notify_one(atomic<T>*);
+template<class T>
+  void atomic_notify_all(volatile atomic<T>*);
+template<class T>
+  void atomic_notify_all(atomic<T>*);
+
+// Atomics for standard typedef types
+
+typedef atomic<bool>               atomic_bool;
+typedef atomic<char>               atomic_char;
+typedef atomic<signed char>        atomic_schar;
+typedef atomic<unsigned char>      atomic_uchar;
+typedef atomic<short>              atomic_short;
+typedef atomic<unsigned short>     atomic_ushort;
+typedef atomic<int>                atomic_int;
+typedef atomic<unsigned int>       atomic_uint;
+typedef atomic<long>               atomic_long;
+typedef atomic<unsigned long>      atomic_ulong;
+typedef atomic<long long>          atomic_llong;
+typedef atomic<unsigned long long> atomic_ullong;
+typedef atomic<char8_t>            atomic_char8_t; // C++20
+typedef atomic<char16_t>           atomic_char16_t;
+typedef atomic<char32_t>           atomic_char32_t;
+typedef atomic<wchar_t>            atomic_wchar_t;
+
+typedef atomic<int_least8_t>   atomic_int_least8_t;
+typedef atomic<uint_least8_t>  atomic_uint_least8_t;
+typedef atomic<int_least16_t>  atomic_int_least16_t;
+typedef atomic<uint_least16_t> atomic_uint_least16_t;
+typedef atomic<int_least32_t>  atomic_int_least32_t;
+typedef atomic<uint_least32_t> atomic_uint_least32_t;
+typedef atomic<int_least64_t>  atomic_int_least64_t;
+typedef atomic<uint_least64_t> atomic_uint_least64_t;
+
+typedef atomic<int_fast8_t>   atomic_int_fast8_t;
+typedef atomic<uint_fast8_t>  atomic_uint_fast8_t;
+typedef atomic<int_fast16_t>  atomic_int_fast16_t;
+typedef atomic<uint_fast16_t> atomic_uint_fast16_t;
+typedef atomic<int_fast32_t>  atomic_int_fast32_t;
+typedef atomic<uint_fast32_t> atomic_uint_fast32_t;
+typedef atomic<int_fast64_t>  atomic_int_fast64_t;
+typedef atomic<uint_fast64_t> atomic_uint_fast64_t;
+
+typedef atomic<int8_t>   atomic_int8_t;
+typedef atomic<uint8_t>  atomic_uint8_t;
+typedef atomic<int16_t>  atomic_int16_t;
+typedef atomic<uint16_t> atomic_uint16_t;
+typedef atomic<int32_t>  atomic_int32_t;
+typedef atomic<uint32_t> atomic_uint32_t;
+typedef atomic<int64_t>  atomic_int64_t;
+typedef atomic<uint64_t> atomic_uint64_t;
+
+typedef atomic<intptr_t>  atomic_intptr_t;
+typedef atomic<uintptr_t> atomic_uintptr_t;
+typedef atomic<size_t>    atomic_size_t;
+typedef atomic<ptrdiff_t> atomic_ptrdiff_t;
+typedef atomic<intmax_t>  atomic_intmax_t;
+typedef atomic<uintmax_t> atomic_uintmax_t;
+
+// flag type and operations
+
+typedef struct atomic_flag
+{
+    atomic_flag() noexcept = default; // until C++20
+    constexpr atomic_flag() noexcept; // since C++20
+    atomic_flag(const atomic_flag&) = delete;
+    atomic_flag& operator=(const atomic_flag&) = delete;
+    atomic_flag& operator=(const atomic_flag&) volatile = delete;
+
+    bool test(memory_order m = memory_order_seq_cst) volatile noexcept;
+    bool test(memory_order m = memory_order_seq_cst) noexcept;
+    bool test_and_set(memory_order m = memory_order_seq_cst) volatile noexcept;
+    bool test_and_set(memory_order m = memory_order_seq_cst) noexcept;
+    void clear(memory_order m = memory_order_seq_cst) volatile noexcept;
+    void clear(memory_order m = memory_order_seq_cst) noexcept;
+
+    void wait(bool, memory_order = memory_order::seq_cst) const volatile noexcept;
+    void wait(bool, memory_order = memory_order::seq_cst) const noexcept;
+    void notify_one() volatile noexcept;
+    void notify_one() noexcept;
+    void notify_all() volatile noexcept;
+    void notify_all() noexcept;
+} atomic_flag;
+
+bool atomic_flag_test(volatile atomic_flag* obj) noexcept;
+bool atomic_flag_test(atomic_flag* obj) noexcept;
+bool atomic_flag_test_explicit(volatile atomic_flag* obj,
+                               memory_order m) noexcept;
+bool atomic_flag_test_explicit(atomic_flag* obj, memory_order m) noexcept;
+bool atomic_flag_test_and_set(volatile atomic_flag* obj) noexcept;
+bool atomic_flag_test_and_set(atomic_flag* obj) noexcept;
+bool atomic_flag_test_and_set_explicit(volatile atomic_flag* obj,
+                                       memory_order m) noexcept;
+bool atomic_flag_test_and_set_explicit(atomic_flag* obj, memory_order m) noexcept;
+void atomic_flag_clear(volatile atomic_flag* obj) noexcept;
+void atomic_flag_clear(atomic_flag* obj) noexcept;
+void atomic_flag_clear_explicit(volatile atomic_flag* obj, memory_order m) noexcept;
+void atomic_flag_clear_explicit(atomic_flag* obj, memory_order m) noexcept;
+
+void atomic_wait(const volatile atomic_flag* obj, T old) noexcept;
+void atomic_wait(const atomic_flag* obj, T old) noexcept;
+void atomic_wait_explicit(const volatile atomic_flag* obj, T old, memory_order m) noexcept;
+void atomic_wait_explicit(const atomic_flag* obj, T old, memory_order m) noexcept;
+void atomic_one(volatile atomic_flag* obj) noexcept;
+void atomic_one(atomic_flag* obj) noexcept;
+void atomic_all(volatile atomic_flag* obj) noexcept;
+void atomic_all(atomic_flag* obj) noexcept;
+
+// fences
+
+void atomic_thread_fence(memory_order m) noexcept;
+void atomic_signal_fence(memory_order m) noexcept;
+
+// deprecated
+
+template <class T>
+  void atomic_init(volatile atomic<T>* obj, atomic<T>::value_type desr) noexcept;
+
+template <class T>
+  void atomic_init(atomic<T>* obj, atomic<T>::value_type desr) noexcept;
+
+#define ATOMIC_VAR_INIT(value) see below
+
+#define ATOMIC_FLAG_INIT see below
+
+}  // std
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <__threading_support>
+#include <cstddef>
+#include <cstdint>
+#include <cstring>
+#include <type_traits>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_HAS_NO_THREADS
+# error <atomic> is not supported on this single threaded system
+#endif
+#ifdef _LIBCPP_HAS_NO_ATOMIC_HEADER
+# error <atomic> is not implemented
+#endif
+#ifdef kill_dependency
+# error C++ standard library is incompatible with <stdatomic.h>
+#endif
+
+#define _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m) \
+  _LIBCPP_DIAGNOSE_WARNING(__m == memory_order_consume || \
+                           __m == memory_order_acquire || \
+                           __m == memory_order_acq_rel,   \
+                        "memory order argument to atomic operation is invalid")
+
+#define _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m) \
+  _LIBCPP_DIAGNOSE_WARNING(__m == memory_order_release || \
+                           __m == memory_order_acq_rel,   \
+                        "memory order argument to atomic operation is invalid")
+
+#define _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__m, __f) \
+  _LIBCPP_DIAGNOSE_WARNING(__f == memory_order_release || \
+                           __f == memory_order_acq_rel,   \
+                        "memory order argument to atomic operation is invalid")
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Figure out what the underlying type for `memory_order` would be if it were
+// declared as an unscoped enum (accounting for -fshort-enums). Use this result
+// to pin the underlying type in C++20.
+enum __legacy_memory_order {
+    __mo_relaxed,
+    __mo_consume,
+    __mo_acquire,
+    __mo_release,
+    __mo_acq_rel,
+    __mo_seq_cst
+};
+
+typedef underlying_type<__legacy_memory_order>::type __memory_order_underlying_t;
+
+#if _LIBCPP_STD_VER > 17
+
+enum class memory_order : __memory_order_underlying_t {
+  relaxed = __mo_relaxed,
+  consume = __mo_consume,
+  acquire = __mo_acquire,
+  release = __mo_release,
+  acq_rel = __mo_acq_rel,
+  seq_cst = __mo_seq_cst
+};
+
+inline constexpr auto memory_order_relaxed = memory_order::relaxed;
+inline constexpr auto memory_order_consume = memory_order::consume;
+inline constexpr auto memory_order_acquire = memory_order::acquire;
+inline constexpr auto memory_order_release = memory_order::release;
+inline constexpr auto memory_order_acq_rel = memory_order::acq_rel;
+inline constexpr auto memory_order_seq_cst = memory_order::seq_cst;
+
+#else
+
+typedef enum memory_order {
+  memory_order_relaxed = __mo_relaxed,
+  memory_order_consume = __mo_consume,
+  memory_order_acquire = __mo_acquire,
+  memory_order_release = __mo_release,
+  memory_order_acq_rel = __mo_acq_rel,
+  memory_order_seq_cst = __mo_seq_cst,
+} memory_order;
+
+#endif // _LIBCPP_STD_VER > 17
+
+template <typename _Tp> _LIBCPP_INLINE_VISIBILITY
+bool __cxx_nonatomic_compare_equal(_Tp const& __lhs, _Tp const& __rhs) {
+    return _VSTD::memcmp(&__lhs, &__rhs, sizeof(_Tp)) == 0;
+}
+
+static_assert((is_same<underlying_type<memory_order>::type, __memory_order_underlying_t>::value),
+  "unexpected underlying type for std::memory_order");
+
+#if defined(_LIBCPP_HAS_GCC_ATOMIC_IMP) || \
+	defined(_LIBCPP_ATOMIC_ONLY_USE_BUILTINS)
+
+// [atomics.types.generic]p1 guarantees _Tp is trivially copyable. Because
+// the default operator= in an object is not volatile, a byte-by-byte copy
+// is required.
+template <typename _Tp, typename _Tv> _LIBCPP_INLINE_VISIBILITY
+typename enable_if<is_assignable<_Tp&, _Tv>::value>::type
+__cxx_atomic_assign_volatile(_Tp& __a_value, _Tv const& __val) {
+  __a_value = __val;
+}
+template <typename _Tp, typename _Tv> _LIBCPP_INLINE_VISIBILITY
+typename enable_if<is_assignable<_Tp&, _Tv>::value>::type
+__cxx_atomic_assign_volatile(_Tp volatile& __a_value, _Tv volatile const& __val) {
+  volatile char* __to = reinterpret_cast<volatile char*>(&__a_value);
+  volatile char* __end = __to + sizeof(_Tp);
+  volatile const char* __from = reinterpret_cast<volatile const char*>(&__val);
+  while (__to != __end)
+    *__to++ = *__from++;
+}
+
+#endif
+
+#if defined(_LIBCPP_HAS_GCC_ATOMIC_IMP)
+
+template <typename _Tp>
+struct __cxx_atomic_base_impl {
+
+  _LIBCPP_INLINE_VISIBILITY
+#ifndef _LIBCPP_CXX03_LANG
+    __cxx_atomic_base_impl() _NOEXCEPT = default;
+#else
+    __cxx_atomic_base_impl() _NOEXCEPT : __a_value() {}
+#endif // _LIBCPP_CXX03_LANG
+  _LIBCPP_CONSTEXPR explicit __cxx_atomic_base_impl(_Tp value) _NOEXCEPT
+    : __a_value(value) {}
+  _Tp __a_value;
+};
+
+_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR int __to_gcc_order(memory_order __order) {
+  // Avoid switch statement to make this a constexpr.
+  return __order == memory_order_relaxed ? __ATOMIC_RELAXED:
+         (__order == memory_order_acquire ? __ATOMIC_ACQUIRE:
+          (__order == memory_order_release ? __ATOMIC_RELEASE:
+           (__order == memory_order_seq_cst ? __ATOMIC_SEQ_CST:
+            (__order == memory_order_acq_rel ? __ATOMIC_ACQ_REL:
+              __ATOMIC_CONSUME))));
+}
+
+_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR int __to_gcc_failure_order(memory_order __order) {
+  // Avoid switch statement to make this a constexpr.
+  return __order == memory_order_relaxed ? __ATOMIC_RELAXED:
+         (__order == memory_order_acquire ? __ATOMIC_ACQUIRE:
+          (__order == memory_order_release ? __ATOMIC_RELAXED:
+           (__order == memory_order_seq_cst ? __ATOMIC_SEQ_CST:
+            (__order == memory_order_acq_rel ? __ATOMIC_ACQUIRE:
+              __ATOMIC_CONSUME))));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_init(volatile __cxx_atomic_base_impl<_Tp>* __a,  _Tp __val) {
+  __cxx_atomic_assign_volatile(__a->__a_value, __val);
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp>* __a,  _Tp __val) {
+  __a->__a_value = __val;
+}
+
+_LIBCPP_INLINE_VISIBILITY inline
+void __cxx_atomic_thread_fence(memory_order __order) {
+  __atomic_thread_fence(__to_gcc_order(__order));
+}
+
+_LIBCPP_INLINE_VISIBILITY inline
+void __cxx_atomic_signal_fence(memory_order __order) {
+  __atomic_signal_fence(__to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_store(volatile __cxx_atomic_base_impl<_Tp>* __a,  _Tp __val,
+                        memory_order __order) {
+  __atomic_store(&__a->__a_value, &__val,
+                 __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp>* __a,  _Tp __val,
+                        memory_order __order) {
+  __atomic_store(&__a->__a_value, &__val,
+                 __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_load(const volatile __cxx_atomic_base_impl<_Tp>* __a,
+                      memory_order __order) {
+  _Tp __ret;
+  __atomic_load(&__a->__a_value, &__ret,
+                __to_gcc_order(__order));
+  return __ret;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_load(const __cxx_atomic_base_impl<_Tp>* __a, memory_order __order) {
+  _Tp __ret;
+  __atomic_load(&__a->__a_value, &__ret,
+                __to_gcc_order(__order));
+  return __ret;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_exchange(volatile __cxx_atomic_base_impl<_Tp>* __a,
+                          _Tp __value, memory_order __order) {
+  _Tp __ret;
+  __atomic_exchange(&__a->__a_value, &__value, &__ret,
+                    __to_gcc_order(__order));
+  return __ret;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp>* __a, _Tp __value,
+                          memory_order __order) {
+  _Tp __ret;
+  __atomic_exchange(&__a->__a_value, &__value, &__ret,
+                    __to_gcc_order(__order));
+  return __ret;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_strong(
+    volatile __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value,
+    memory_order __success, memory_order __failure) {
+  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
+                                   false,
+                                   __to_gcc_order(__success),
+                                   __to_gcc_failure_order(__failure));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_strong(
+    __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success,
+    memory_order __failure) {
+  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
+                                   false,
+                                   __to_gcc_order(__success),
+                                   __to_gcc_failure_order(__failure));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_weak(
+    volatile __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value,
+    memory_order __success, memory_order __failure) {
+  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
+                                   true,
+                                   __to_gcc_order(__success),
+                                   __to_gcc_failure_order(__failure));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_weak(
+    __cxx_atomic_base_impl<_Tp>* __a, _Tp* __expected, _Tp __value, memory_order __success,
+    memory_order __failure) {
+  return __atomic_compare_exchange(&__a->__a_value, __expected, &__value,
+                                   true,
+                                   __to_gcc_order(__success),
+                                   __to_gcc_failure_order(__failure));
+}
+
+template <typename _Tp>
+struct __skip_amt { enum {value = 1}; };
+
+template <typename _Tp>
+struct __skip_amt<_Tp*> { enum {value = sizeof(_Tp)}; };
+
+// FIXME: Haven't figured out what the spec says about using arrays with
+// atomic_fetch_add. Force a failure rather than creating bad behavior.
+template <typename _Tp>
+struct __skip_amt<_Tp[]> { };
+template <typename _Tp, int n>
+struct __skip_amt<_Tp[n]> { };
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_add(volatile __cxx_atomic_base_impl<_Tp>* __a,
+                           _Td __delta, memory_order __order) {
+  return __atomic_fetch_add(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp>* __a, _Td __delta,
+                           memory_order __order) {
+  return __atomic_fetch_add(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_sub(volatile __cxx_atomic_base_impl<_Tp>* __a,
+                           _Td __delta, memory_order __order) {
+  return __atomic_fetch_sub(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp>* __a, _Td __delta,
+                           memory_order __order) {
+  return __atomic_fetch_sub(&__a->__a_value, __delta * __skip_amt<_Tp>::value,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_and(volatile __cxx_atomic_base_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order __order) {
+  return __atomic_fetch_and(&__a->__a_value, __pattern,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order __order) {
+  return __atomic_fetch_and(&__a->__a_value, __pattern,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_or(volatile __cxx_atomic_base_impl<_Tp>* __a,
+                          _Tp __pattern, memory_order __order) {
+  return __atomic_fetch_or(&__a->__a_value, __pattern,
+                           __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp>* __a, _Tp __pattern,
+                          memory_order __order) {
+  return __atomic_fetch_or(&__a->__a_value, __pattern,
+                           __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_xor(volatile __cxx_atomic_base_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order __order) {
+  return __atomic_fetch_xor(&__a->__a_value, __pattern,
+                            __to_gcc_order(__order));
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp>* __a, _Tp __pattern,
+                           memory_order __order) {
+  return __atomic_fetch_xor(&__a->__a_value, __pattern,
+                            __to_gcc_order(__order));
+}
+
+#define __cxx_atomic_is_lock_free(__s) __atomic_is_lock_free(__s, 0)
+
+#elif defined(_LIBCPP_HAS_C_ATOMIC_IMP) || defined(_LIBCPP_COMPILER_MSVC)
+
+#if defined(_LIBCPP_COMPILER_MSVC)
+_LIBCPP_END_NAMESPACE_STD
+#include <__support/win32/atomic_win32.h>
+_LIBCPP_BEGIN_NAMESPACE_STD
+#endif
+
+template <typename _Tp>
+struct __cxx_atomic_base_impl {
+
+  _LIBCPP_INLINE_VISIBILITY
+#ifndef _LIBCPP_CXX03_LANG
+    __cxx_atomic_base_impl() _NOEXCEPT = default;
+#else
+    __cxx_atomic_base_impl() _NOEXCEPT : __a_value() {}
+#endif // _LIBCPP_CXX03_LANG
+  _LIBCPP_CONSTEXPR explicit __cxx_atomic_base_impl(_Tp value) _NOEXCEPT
+    : __a_value(value) {}
+  _LIBCPP_DISABLE_EXTENSION_WARNING _Atomic(_Tp) __a_value;
+};
+
+#define __cxx_atomic_is_lock_free(__s) __c11_atomic_is_lock_free(__s)
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4141 )
+#endif
+_LIBCPP_INLINE_VISIBILITY inline
+void __cxx_atomic_thread_fence(memory_order __order) _NOEXCEPT {
+    __c11_atomic_thread_fence(static_cast<__memory_order_underlying_t>(__order));
+}
+
+_LIBCPP_INLINE_VISIBILITY inline
+void __cxx_atomic_signal_fence(memory_order __order) _NOEXCEPT {
+    __c11_atomic_signal_fence(static_cast<__memory_order_underlying_t>(__order));
+}
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __val) _NOEXCEPT {
+    __c11_atomic_init(&__a->__a_value, __val);
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_init(__cxx_atomic_base_impl<_Tp> * __a, _Tp __val) _NOEXCEPT {
+    __c11_atomic_init(&__a->__a_value, __val);
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __val, memory_order __order) _NOEXCEPT {
+    __c11_atomic_store(&__a->__a_value, __val, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_store(__cxx_atomic_base_impl<_Tp> * __a, _Tp __val, memory_order __order) _NOEXCEPT {
+    __c11_atomic_store(&__a->__a_value, __val, static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_load(__cxx_atomic_base_impl<_Tp> const volatile* __a, memory_order __order) _NOEXCEPT {
+    using __ptr_type = typename remove_const<decltype(__a->__a_value)>::type*;
+    return __c11_atomic_load(const_cast<__ptr_type>(&__a->__a_value), static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_load(__cxx_atomic_base_impl<_Tp> const* __a, memory_order __order) _NOEXCEPT {
+    using __ptr_type = typename remove_const<decltype(__a->__a_value)>::type*;
+    return __c11_atomic_load(const_cast<__ptr_type>(&__a->__a_value), static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __value, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_exchange(&__a->__a_value, __value, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_exchange(__cxx_atomic_base_impl<_Tp> * __a, _Tp __value, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_exchange(&__a->__a_value, __value, static_cast<__memory_order_underlying_t>(__order));
+}
+
+// Disable double inline warning
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4141 )
+#endif
+_LIBCPP_INLINE_VISIBILITY inline _LIBCPP_CONSTEXPR memory_order __to_failure_order(memory_order __order) {
+  // Avoid switch statement to make this a constexpr.
+  return __order == memory_order_release ? memory_order_relaxed:
+         (__order == memory_order_acq_rel ? memory_order_acquire:
+             __order);
+}
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
+    return __c11_atomic_compare_exchange_strong(&__a->__a_value, __expected, __value, static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_base_impl<_Tp> * __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
+    return __c11_atomic_compare_exchange_strong(&__a->__a_value, __expected, __value, static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
+    return __c11_atomic_compare_exchange_weak(&__a->__a_value, __expected, __value, static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_base_impl<_Tp> * __a, _Tp* __expected, _Tp __value, memory_order __success, memory_order __failure) _NOEXCEPT {
+    return __c11_atomic_compare_exchange_weak(&__a->__a_value, __expected, __value,  static_cast<__memory_order_underlying_t>(__success), static_cast<__memory_order_underlying_t>(__to_failure_order(__failure)));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp> * __a, _Tp __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp* __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp* __cxx_atomic_fetch_add(__cxx_atomic_base_impl<_Tp*> * __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_add(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp> * __a, _Tp __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp* __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp*> volatile* __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp* __cxx_atomic_fetch_sub(__cxx_atomic_base_impl<_Tp*> * __a, ptrdiff_t __delta, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_sub(&__a->__a_value, __delta, static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_and(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_and(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_and(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_or(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_or(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_or(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp> volatile* __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_xor(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
+}
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_xor(__cxx_atomic_base_impl<_Tp> * __a, _Tp __pattern, memory_order __order) _NOEXCEPT {
+    return __c11_atomic_fetch_xor(&__a->__a_value, __pattern, static_cast<__memory_order_underlying_t>(__order));
+}
+
+#endif // _LIBCPP_HAS_GCC_ATOMIC_IMP, _LIBCPP_HAS_C_ATOMIC_IMP
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp kill_dependency(_Tp __y) _NOEXCEPT
+{
+    return __y;
+}
+
+#if defined(__CLANG_ATOMIC_BOOL_LOCK_FREE)
+# define ATOMIC_BOOL_LOCK_FREE      __CLANG_ATOMIC_BOOL_LOCK_FREE
+# define ATOMIC_CHAR_LOCK_FREE      __CLANG_ATOMIC_CHAR_LOCK_FREE
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+# define ATOMIC_CHAR8_T_LOCK_FREE   __CLANG_ATOMIC_CHAR8_T_LOCK_FREE
+#endif
+# define ATOMIC_CHAR16_T_LOCK_FREE  __CLANG_ATOMIC_CHAR16_T_LOCK_FREE
+# define ATOMIC_CHAR32_T_LOCK_FREE  __CLANG_ATOMIC_CHAR32_T_LOCK_FREE
+# define ATOMIC_WCHAR_T_LOCK_FREE   __CLANG_ATOMIC_WCHAR_T_LOCK_FREE
+# define ATOMIC_SHORT_LOCK_FREE     __CLANG_ATOMIC_SHORT_LOCK_FREE
+# define ATOMIC_INT_LOCK_FREE       __CLANG_ATOMIC_INT_LOCK_FREE
+# define ATOMIC_LONG_LOCK_FREE      __CLANG_ATOMIC_LONG_LOCK_FREE
+# define ATOMIC_LLONG_LOCK_FREE     __CLANG_ATOMIC_LLONG_LOCK_FREE
+# define ATOMIC_POINTER_LOCK_FREE   __CLANG_ATOMIC_POINTER_LOCK_FREE
+#elif defined(__GCC_ATOMIC_BOOL_LOCK_FREE)
+# define ATOMIC_BOOL_LOCK_FREE      __GCC_ATOMIC_BOOL_LOCK_FREE
+# define ATOMIC_CHAR_LOCK_FREE      __GCC_ATOMIC_CHAR_LOCK_FREE
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+# define ATOMIC_CHAR8_T_LOCK_FREE   __GCC_ATOMIC_CHAR8_T_LOCK_FREE
+#endif
+# define ATOMIC_CHAR16_T_LOCK_FREE  __GCC_ATOMIC_CHAR16_T_LOCK_FREE
+# define ATOMIC_CHAR32_T_LOCK_FREE  __GCC_ATOMIC_CHAR32_T_LOCK_FREE
+# define ATOMIC_WCHAR_T_LOCK_FREE   __GCC_ATOMIC_WCHAR_T_LOCK_FREE
+# define ATOMIC_SHORT_LOCK_FREE     __GCC_ATOMIC_SHORT_LOCK_FREE
+# define ATOMIC_INT_LOCK_FREE       __GCC_ATOMIC_INT_LOCK_FREE
+# define ATOMIC_LONG_LOCK_FREE      __GCC_ATOMIC_LONG_LOCK_FREE
+# define ATOMIC_LLONG_LOCK_FREE     __GCC_ATOMIC_LLONG_LOCK_FREE
+# define ATOMIC_POINTER_LOCK_FREE   __GCC_ATOMIC_POINTER_LOCK_FREE
+#endif
+
+#ifdef _LIBCPP_ATOMIC_ONLY_USE_BUILTINS
+
+template<typename _Tp>
+struct __cxx_atomic_lock_impl {
+
+  _LIBCPP_INLINE_VISIBILITY
+  __cxx_atomic_lock_impl() _NOEXCEPT
+    : __a_value(), __a_lock(0) {}
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR explicit
+  __cxx_atomic_lock_impl(_Tp value) _NOEXCEPT
+    : __a_value(value), __a_lock(0) {}
+
+  _Tp __a_value;
+  mutable __cxx_atomic_base_impl<_LIBCPP_ATOMIC_FLAG_TYPE> __a_lock;
+
+  _LIBCPP_INLINE_VISIBILITY void __lock() const volatile {
+    while(1 == __cxx_atomic_exchange(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(true), memory_order_acquire))
+        /*spin*/;
+  }
+  _LIBCPP_INLINE_VISIBILITY void __lock() const {
+    while(1 == __cxx_atomic_exchange(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(true), memory_order_acquire))
+        /*spin*/;
+  }
+  _LIBCPP_INLINE_VISIBILITY void __unlock() const volatile {
+    __cxx_atomic_store(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(false), memory_order_release);
+  }
+  _LIBCPP_INLINE_VISIBILITY void __unlock() const {
+    __cxx_atomic_store(&__a_lock, _LIBCPP_ATOMIC_FLAG_TYPE(false), memory_order_release);
+  }
+  _LIBCPP_INLINE_VISIBILITY _Tp __read() const volatile {
+    __lock();
+    _Tp __old;
+    __cxx_atomic_assign_volatile(__old, __a_value);
+    __unlock();
+    return __old;
+  }
+  _LIBCPP_INLINE_VISIBILITY _Tp __read() const {
+    __lock();
+    _Tp __old = __a_value;
+    __unlock();
+    return __old;
+  }
+};
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_init(volatile __cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val) {
+  __cxx_atomic_assign_volatile(__a->__a_value, __val);
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_init(__cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val) {
+  __a->__a_value = __val;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_store(volatile __cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val, memory_order) {
+  __a->__lock();
+  __cxx_atomic_assign_volatile(__a->__a_value, __val);
+  __a->__unlock();
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void __cxx_atomic_store(__cxx_atomic_lock_impl<_Tp>* __a,  _Tp __val, memory_order) {
+  __a->__lock();
+  __a->__a_value = __val;
+  __a->__unlock();
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_load(const volatile __cxx_atomic_lock_impl<_Tp>* __a, memory_order) {
+  return __a->__read();
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_load(const __cxx_atomic_lock_impl<_Tp>* __a, memory_order) {
+  return __a->__read();
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_exchange(volatile __cxx_atomic_lock_impl<_Tp>* __a, _Tp __value, memory_order) {
+  __a->__lock();
+  _Tp __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, __value);
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_exchange(__cxx_atomic_lock_impl<_Tp>* __a, _Tp __value, memory_order) {
+  __a->__lock();
+  _Tp __old = __a->__a_value;
+  __a->__a_value = __value;
+  __a->__unlock();
+  return __old;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_strong(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                                          _Tp* __expected, _Tp __value, memory_order, memory_order) {
+  _Tp __temp;
+  __a->__lock();
+  __cxx_atomic_assign_volatile(__temp, __a->__a_value);
+  bool __ret = (_VSTD::memcmp(&__temp, __expected, sizeof(_Tp)) == 0);
+  if(__ret)
+    __cxx_atomic_assign_volatile(__a->__a_value, __value);
+  else
+    __cxx_atomic_assign_volatile(*__expected, __a->__a_value);
+  __a->__unlock();
+  return __ret;
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_strong(__cxx_atomic_lock_impl<_Tp>* __a,
+                                          _Tp* __expected, _Tp __value, memory_order, memory_order) {
+  __a->__lock();
+  bool __ret = (_VSTD::memcmp(&__a->__a_value, __expected, sizeof(_Tp)) == 0);
+  if(__ret)
+    _VSTD::memcpy(&__a->__a_value, &__value, sizeof(_Tp));
+  else
+    _VSTD::memcpy(__expected, &__a->__a_value, sizeof(_Tp));
+  __a->__unlock();
+  return __ret;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_weak(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                                        _Tp* __expected, _Tp __value, memory_order, memory_order) {
+  _Tp __temp;
+  __a->__lock();
+  __cxx_atomic_assign_volatile(__temp, __a->__a_value);
+  bool __ret = (_VSTD::memcmp(&__temp, __expected, sizeof(_Tp)) == 0);
+  if(__ret)
+    __cxx_atomic_assign_volatile(__a->__a_value, __value);
+  else
+    __cxx_atomic_assign_volatile(*__expected, __a->__a_value);
+  __a->__unlock();
+  return __ret;
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool __cxx_atomic_compare_exchange_weak(__cxx_atomic_lock_impl<_Tp>* __a,
+                                        _Tp* __expected, _Tp __value, memory_order, memory_order) {
+  __a->__lock();
+  bool __ret = (_VSTD::memcmp(&__a->__a_value, __expected, sizeof(_Tp)) == 0);
+  if(__ret)
+    _VSTD::memcpy(&__a->__a_value, &__value, sizeof(_Tp));
+  else
+    _VSTD::memcpy(__expected, &__a->__a_value, sizeof(_Tp));
+  __a->__unlock();
+  return __ret;
+}
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_add(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                           _Td __delta, memory_order) {
+  __a->__lock();
+  _Tp __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old + __delta));
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_add(__cxx_atomic_lock_impl<_Tp>* __a,
+                           _Td __delta, memory_order) {
+  __a->__lock();
+  _Tp __old = __a->__a_value;
+  __a->__a_value += __delta;
+  __a->__unlock();
+  return __old;
+}
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp* __cxx_atomic_fetch_add(volatile __cxx_atomic_lock_impl<_Tp*>* __a,
+                           ptrdiff_t __delta, memory_order) {
+  __a->__lock();
+  _Tp* __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, __old + __delta);
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp* __cxx_atomic_fetch_add(__cxx_atomic_lock_impl<_Tp*>* __a,
+                           ptrdiff_t __delta, memory_order) {
+  __a->__lock();
+  _Tp* __old = __a->__a_value;
+  __a->__a_value += __delta;
+  __a->__unlock();
+  return __old;
+}
+
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_sub(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                           _Td __delta, memory_order) {
+  __a->__lock();
+  _Tp __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old - __delta));
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp, typename _Td>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_sub(__cxx_atomic_lock_impl<_Tp>* __a,
+                           _Td __delta, memory_order) {
+  __a->__lock();
+  _Tp __old = __a->__a_value;
+  __a->__a_value -= __delta;
+  __a->__unlock();
+  return __old;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_and(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order) {
+  __a->__lock();
+  _Tp __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old & __pattern));
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_and(__cxx_atomic_lock_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order) {
+  __a->__lock();
+  _Tp __old = __a->__a_value;
+  __a->__a_value &= __pattern;
+  __a->__unlock();
+  return __old;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_or(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                          _Tp __pattern, memory_order) {
+  __a->__lock();
+  _Tp __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old | __pattern));
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_or(__cxx_atomic_lock_impl<_Tp>* __a,
+                          _Tp __pattern, memory_order) {
+  __a->__lock();
+  _Tp __old = __a->__a_value;
+  __a->__a_value |= __pattern;
+  __a->__unlock();
+  return __old;
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_xor(volatile __cxx_atomic_lock_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order) {
+  __a->__lock();
+  _Tp __old;
+  __cxx_atomic_assign_volatile(__old, __a->__a_value);
+  __cxx_atomic_assign_volatile(__a->__a_value, _Tp(__old ^ __pattern));
+  __a->__unlock();
+  return __old;
+}
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __cxx_atomic_fetch_xor(__cxx_atomic_lock_impl<_Tp>* __a,
+                           _Tp __pattern, memory_order) {
+  __a->__lock();
+  _Tp __old = __a->__a_value;
+  __a->__a_value ^= __pattern;
+  __a->__unlock();
+  return __old;
+}
+
+#ifdef __cpp_lib_atomic_is_always_lock_free
+
+template<typename _Tp> struct __cxx_is_always_lock_free {
+    enum { __value = __atomic_always_lock_free(sizeof(_Tp), 0) }; };
+
+#else
+
+template<typename _Tp> struct __cxx_is_always_lock_free { enum { __value = false }; };
+// Implementations must match the C ATOMIC_*_LOCK_FREE macro values.
+template<> struct __cxx_is_always_lock_free<bool> { enum { __value = 2 == ATOMIC_BOOL_LOCK_FREE }; };
+template<> struct __cxx_is_always_lock_free<char> { enum { __value = 2 == ATOMIC_CHAR_LOCK_FREE }; };
+template<> struct __cxx_is_always_lock_free<signed char> { enum { __value = 2 == ATOMIC_CHAR_LOCK_FREE }; };
+template<> struct __cxx_is_always_lock_free<unsigned char> { enum { __value = 2 == ATOMIC_CHAR_LOCK_FREE }; };
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+template<> struct __cxx_is_always_lock_free<char8_t> { enum { __value = 2 == ATOMIC_CHAR8_T_LOCK_FREE }; };
+#endif
+template<> struct __cxx_is_always_lock_free<char16_t> { enum { __value = 2 == ATOMIC_CHAR16_T_LOCK_FREE }; };
+template<> struct __cxx_is_always_lock_free<char32_t> { enum { __value = 2 == ATOMIC_CHAR32_T_LOCK_FREE }; };
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template<> struct __cxx_is_always_lock_free<wchar_t> { enum { __value = 2 == ATOMIC_WCHAR_T_LOCK_FREE }; };
+#endif
+template<> struct __cxx_is_always_lock_free<short> { enum { __value = 2 == ATOMIC_SHORT_LOCK_FREE }; };
+template<> struct __cxx_is_always_lock_free<unsigned short> { enum { __value = 2 == ATOMIC_SHORT_LOCK_FREE }; };
+template<> struct __cxx_is_always_lock_free<int> { enum { __value = 2 == ATOMIC_INT_LOCK_FREE }; };
+template<> struct __cxx_is_always_lock_free<unsigned int> { enum { __value = 2 == ATOMIC_INT_LOCK_FREE }; };
+template<> struct __cxx_is_always_lock_free<long> { enum { __value = 2 == ATOMIC_LONG_LOCK_FREE }; };
+template<> struct __cxx_is_always_lock_free<unsigned long> { enum { __value = 2 == ATOMIC_LONG_LOCK_FREE }; };
+template<> struct __cxx_is_always_lock_free<long long> { enum { __value = 2 == ATOMIC_LLONG_LOCK_FREE }; };
+template<> struct __cxx_is_always_lock_free<unsigned long long> { enum { __value = 2 == ATOMIC_LLONG_LOCK_FREE }; };
+template<typename _Tp> struct __cxx_is_always_lock_free<_Tp*> { enum { __value = 2 == ATOMIC_POINTER_LOCK_FREE }; };
+template<> struct __cxx_is_always_lock_free<std::nullptr_t> { enum { __value = 2 == ATOMIC_POINTER_LOCK_FREE }; };
+
+#endif //__cpp_lib_atomic_is_always_lock_free
+
+template <typename _Tp,
+          typename _Base = typename conditional<__cxx_is_always_lock_free<_Tp>::__value,
+                                                __cxx_atomic_base_impl<_Tp>,
+                                                __cxx_atomic_lock_impl<_Tp> >::type>
+#else
+template <typename _Tp,
+          typename _Base = __cxx_atomic_base_impl<_Tp> >
+#endif //_LIBCPP_ATOMIC_ONLY_USE_BUILTINS
+struct __cxx_atomic_impl : public _Base {
+    static_assert(is_trivially_copyable<_Tp>::value,
+      "std::atomic<Tp> requires that 'Tp' be a trivially copyable type");
+
+  _LIBCPP_INLINE_VISIBILITY __cxx_atomic_impl() _NOEXCEPT _LIBCPP_DEFAULT
+  _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR explicit __cxx_atomic_impl(_Tp value) _NOEXCEPT
+    : _Base(value) {}
+};
+
+#ifdef __linux__
+    using __cxx_contention_t = int32_t;
+#else
+    using __cxx_contention_t = int64_t;
+#endif //__linux__
+
+using __cxx_atomic_contention_t = __cxx_atomic_impl<__cxx_contention_t>;
+
+#ifndef _LIBCPP_HAS_NO_PLATFORM_WAIT
+
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(void const volatile*);
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(void const volatile*);
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t __libcpp_atomic_monitor(void const volatile*);
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __libcpp_atomic_wait(void const volatile*, __cxx_contention_t);
+
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_one(__cxx_atomic_contention_t const volatile*);
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __cxx_atomic_notify_all(__cxx_atomic_contention_t const volatile*);
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI __cxx_contention_t __libcpp_atomic_monitor(__cxx_atomic_contention_t const volatile*);
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI void __libcpp_atomic_wait(__cxx_atomic_contention_t const volatile*, __cxx_contention_t);
+
+template <class _Atp, class _Fn>
+struct __libcpp_atomic_wait_backoff_impl {
+    _Atp* __a;
+    _Fn __test_fn;
+    _LIBCPP_AVAILABILITY_SYNC
+    _LIBCPP_INLINE_VISIBILITY bool operator()(chrono::nanoseconds __elapsed) const
+    {
+        if(__elapsed > chrono::microseconds(64))
+        {
+            auto const __monitor = __libcpp_atomic_monitor(__a);
+            if(__test_fn())
+                return true;
+            __libcpp_atomic_wait(__a, __monitor);
+        }
+        else if(__elapsed > chrono::microseconds(4))
+            __libcpp_thread_yield();
+        else
+            {} // poll
+        return false;
+    }
+};
+
+template <class _Atp, class _Fn>
+_LIBCPP_AVAILABILITY_SYNC
+_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp* __a, _Fn && __test_fn)
+{
+    __libcpp_atomic_wait_backoff_impl<_Atp, typename decay<_Fn>::type> __backoff_fn = {__a, __test_fn};
+    return __libcpp_thread_poll_with_backoff(__test_fn, __backoff_fn);
+}
+
+#else // _LIBCPP_HAS_NO_PLATFORM_WAIT
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY void __cxx_atomic_notify_all(__cxx_atomic_impl<_Tp> const volatile*) { }
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY void __cxx_atomic_notify_one(__cxx_atomic_impl<_Tp> const volatile*) { }
+template <class _Atp, class _Fn>
+_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp*, _Fn && __test_fn)
+{
+    return __libcpp_thread_poll_with_backoff(__test_fn, __libcpp_timed_backoff_policy());
+}
+
+#endif // _LIBCPP_HAS_NO_PLATFORM_WAIT
+
+template <class _Atp, class _Tp>
+struct __cxx_atomic_wait_test_fn_impl {
+    _Atp* __a;
+    _Tp __val;
+    memory_order __order;
+    _LIBCPP_INLINE_VISIBILITY bool operator()() const
+    {
+        return !__cxx_nonatomic_compare_equal(__cxx_atomic_load(__a, __order), __val);
+    }
+};
+
+template <class _Atp, class _Tp>
+_LIBCPP_AVAILABILITY_SYNC
+_LIBCPP_INLINE_VISIBILITY bool __cxx_atomic_wait(_Atp* __a, _Tp const __val, memory_order __order)
+{
+    __cxx_atomic_wait_test_fn_impl<_Atp, _Tp> __test_fn = {__a, __val, __order};
+    return __cxx_atomic_wait(__a, __test_fn);
+}
+
+// general atomic<T>
+
+template <class _Tp, bool = is_integral<_Tp>::value && !is_same<_Tp, bool>::value>
+struct __atomic_base  // false
+{
+    mutable __cxx_atomic_impl<_Tp> __a_;
+
+#if defined(__cpp_lib_atomic_is_always_lock_free)
+  static _LIBCPP_CONSTEXPR bool is_always_lock_free = __atomic_always_lock_free(sizeof(__a_), 0);
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool is_lock_free() const volatile _NOEXCEPT
+        {return __cxx_atomic_is_lock_free(sizeof(_Tp));}
+    _LIBCPP_INLINE_VISIBILITY
+    bool is_lock_free() const _NOEXCEPT
+        {return static_cast<__atomic_base const volatile*>(this)->is_lock_free();}
+    _LIBCPP_INLINE_VISIBILITY
+    void store(_Tp __d, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+      _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
+        {__cxx_atomic_store(&__a_, __d, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    void store(_Tp __d, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+      _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
+        {__cxx_atomic_store(&__a_, __d, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp load(memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
+      _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
+        {return __cxx_atomic_load(&__a_, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp load(memory_order __m = memory_order_seq_cst) const _NOEXCEPT
+      _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
+        {return __cxx_atomic_load(&__a_, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    operator _Tp() const volatile _NOEXCEPT {return load();}
+    _LIBCPP_INLINE_VISIBILITY
+    operator _Tp() const _NOEXCEPT          {return load();}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return __cxx_atomic_exchange(&__a_, __d, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp exchange(_Tp __d, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return __cxx_atomic_exchange(&__a_, __d, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_weak(_Tp& __e, _Tp __d,
+                               memory_order __s, memory_order __f) volatile _NOEXCEPT
+      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+        {return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_weak(_Tp& __e, _Tp __d,
+                               memory_order __s, memory_order __f) _NOEXCEPT
+      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+        {return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __s, __f);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_strong(_Tp& __e, _Tp __d,
+                                 memory_order __s, memory_order __f) volatile _NOEXCEPT
+      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+        {return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_strong(_Tp& __e, _Tp __d,
+                                 memory_order __s, memory_order __f) _NOEXCEPT
+      _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+        {return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __s, __f);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_weak(_Tp& __e, _Tp __d,
+                              memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_weak(_Tp& __e, _Tp __d,
+                               memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return __cxx_atomic_compare_exchange_weak(&__a_, &__e, __d, __m, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_strong(_Tp& __e, _Tp __d,
+                              memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool compare_exchange_strong(_Tp& __e, _Tp __d,
+                                 memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return __cxx_atomic_compare_exchange_strong(&__a_, &__e, __d, __m, __m);}
+
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void wait(_Tp __v, memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
+        {__cxx_atomic_wait(&__a_, __v, __m);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void wait(_Tp __v, memory_order __m = memory_order_seq_cst) const _NOEXCEPT
+        {__cxx_atomic_wait(&__a_, __v, __m);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_one() volatile _NOEXCEPT
+        {__cxx_atomic_notify_one(&__a_);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_one() _NOEXCEPT
+        {__cxx_atomic_notify_one(&__a_);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_all() volatile _NOEXCEPT
+        {__cxx_atomic_notify_all(&__a_);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY void notify_all() _NOEXCEPT
+        {__cxx_atomic_notify_all(&__a_);}
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY constexpr
+    __atomic_base() noexcept(is_nothrow_default_constructible_v<_Tp>) : __a_(_Tp()) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    __atomic_base() _NOEXCEPT _LIBCPP_DEFAULT
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    __atomic_base(_Tp __d) _NOEXCEPT : __a_(__d) {}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4522 )
+#endif
+#ifndef _LIBCPP_CXX03_LANG
+    __atomic_base(const __atomic_base&) = delete;
+#else
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    __atomic_base(const __atomic_base&);
+#endif
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+};
+
+#if defined(__cpp_lib_atomic_is_always_lock_free)
+template <class _Tp, bool __b>
+_LIBCPP_CONSTEXPR bool __atomic_base<_Tp, __b>::is_always_lock_free;
+#endif
+
+// atomic<Integral>
+
+template <class _Tp>
+struct __atomic_base<_Tp, true>
+    : public __atomic_base<_Tp, false>
+{
+    typedef __atomic_base<_Tp, false> __base;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    __atomic_base() _NOEXCEPT _LIBCPP_DEFAULT
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR __atomic_base(_Tp __d) _NOEXCEPT : __base(__d) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return __cxx_atomic_fetch_add(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_add(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return __cxx_atomic_fetch_add(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_sub(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return __cxx_atomic_fetch_and(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_and(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return __cxx_atomic_fetch_and(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return __cxx_atomic_fetch_or(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_or(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return __cxx_atomic_fetch_or(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return __cxx_atomic_fetch_xor(&this->__a_, __op, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp fetch_xor(_Tp __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return __cxx_atomic_fetch_xor(&this->__a_, __op, __m);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator++(int) volatile _NOEXCEPT      {return fetch_add(_Tp(1));}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator++(int) _NOEXCEPT               {return fetch_add(_Tp(1));}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator--(int) volatile _NOEXCEPT      {return fetch_sub(_Tp(1));}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator--(int) _NOEXCEPT               {return fetch_sub(_Tp(1));}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator++() volatile _NOEXCEPT         {return fetch_add(_Tp(1)) + _Tp(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator++() _NOEXCEPT                  {return fetch_add(_Tp(1)) + _Tp(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator--() volatile _NOEXCEPT         {return fetch_sub(_Tp(1)) - _Tp(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator--() _NOEXCEPT                  {return fetch_sub(_Tp(1)) - _Tp(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator+=(_Tp __op) volatile _NOEXCEPT {return fetch_add(__op) + __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator+=(_Tp __op) _NOEXCEPT          {return fetch_add(__op) + __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator-=(_Tp __op) volatile _NOEXCEPT {return fetch_sub(__op) - __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator-=(_Tp __op) _NOEXCEPT          {return fetch_sub(__op) - __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator&=(_Tp __op) volatile _NOEXCEPT {return fetch_and(__op) & __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator&=(_Tp __op) _NOEXCEPT          {return fetch_and(__op) & __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator|=(_Tp __op) volatile _NOEXCEPT {return fetch_or(__op) | __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator|=(_Tp __op) _NOEXCEPT          {return fetch_or(__op) | __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator^=(_Tp __op) volatile _NOEXCEPT {return fetch_xor(__op) ^ __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator^=(_Tp __op) _NOEXCEPT          {return fetch_xor(__op) ^ __op;}
+};
+
+// atomic<T>
+
+template <class _Tp>
+struct atomic
+    : public __atomic_base<_Tp>
+{
+    typedef __atomic_base<_Tp> __base;
+    typedef _Tp value_type;
+    typedef value_type difference_type;
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    atomic() = default;
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    atomic() _NOEXCEPT _LIBCPP_DEFAULT
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR atomic(_Tp __d) _NOEXCEPT : __base(__d) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator=(_Tp __d) volatile _NOEXCEPT
+        {__base::store(__d); return __d;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator=(_Tp __d) _NOEXCEPT
+        {__base::store(__d); return __d;}
+
+    atomic& operator=(const atomic&) = delete;
+    atomic& operator=(const atomic&) volatile = delete;
+};
+
+// atomic<T*>
+
+template <class _Tp>
+struct atomic<_Tp*>
+    : public __atomic_base<_Tp*>
+{
+    typedef __atomic_base<_Tp*> __base;
+    typedef _Tp* value_type;
+    typedef ptrdiff_t difference_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    atomic() _NOEXCEPT _LIBCPP_DEFAULT
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR atomic(_Tp* __d) _NOEXCEPT : __base(__d) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator=(_Tp* __d) volatile _NOEXCEPT
+        {__base::store(__d); return __d;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator=(_Tp* __d) _NOEXCEPT
+        {__base::store(__d); return __d;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT {
+        // __atomic_fetch_add accepts function pointers, guard against them.
+        static_assert(!is_function<typename remove_pointer<_Tp>::type>::value, "Pointer to function isn't allowed");
+        return __cxx_atomic_fetch_add(&this->__a_, __op, __m);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* fetch_add(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT {
+        // __atomic_fetch_add accepts function pointers, guard against them.
+        static_assert(!is_function<typename remove_pointer<_Tp>::type>::value, "Pointer to function isn't allowed");
+        return __cxx_atomic_fetch_add(&this->__a_, __op, __m);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT {
+        // __atomic_fetch_add accepts function pointers, guard against them.
+        static_assert(!is_function<typename remove_pointer<_Tp>::type>::value, "Pointer to function isn't allowed");
+        return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* fetch_sub(ptrdiff_t __op, memory_order __m = memory_order_seq_cst) _NOEXCEPT {
+        // __atomic_fetch_add accepts function pointers, guard against them.
+        static_assert(!is_function<typename remove_pointer<_Tp>::type>::value, "Pointer to function isn't allowed");
+        return __cxx_atomic_fetch_sub(&this->__a_, __op, __m);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator++(int) volatile _NOEXCEPT            {return fetch_add(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator++(int) _NOEXCEPT                     {return fetch_add(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator--(int) volatile _NOEXCEPT            {return fetch_sub(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator--(int) _NOEXCEPT                     {return fetch_sub(1);}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator++() volatile _NOEXCEPT               {return fetch_add(1) + 1;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator++() _NOEXCEPT                        {return fetch_add(1) + 1;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator--() volatile _NOEXCEPT               {return fetch_sub(1) - 1;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator--() _NOEXCEPT                        {return fetch_sub(1) - 1;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator+=(ptrdiff_t __op) volatile _NOEXCEPT {return fetch_add(__op) + __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator+=(ptrdiff_t __op) _NOEXCEPT          {return fetch_add(__op) + __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator-=(ptrdiff_t __op) volatile _NOEXCEPT {return fetch_sub(__op) - __op;}
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp* operator-=(ptrdiff_t __op) _NOEXCEPT          {return fetch_sub(__op) - __op;}
+
+    atomic& operator=(const atomic&) = delete;
+    atomic& operator=(const atomic&) volatile = delete;
+};
+
+// atomic_is_lock_free
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_is_lock_free(const volatile atomic<_Tp>* __o) _NOEXCEPT
+{
+    return __o->is_lock_free();
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_is_lock_free(const atomic<_Tp>* __o) _NOEXCEPT
+{
+    return __o->is_lock_free();
+}
+
+// atomic_init
+
+template <class _Tp>
+_LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_INLINE_VISIBILITY
+void
+atomic_init(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    __cxx_atomic_init(&__o->__a_, __d);
+}
+
+template <class _Tp>
+_LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_INLINE_VISIBILITY
+void
+atomic_init(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    __cxx_atomic_init(&__o->__a_, __d);
+}
+
+// atomic_store
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void
+atomic_store(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    __o->store(__d);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void
+atomic_store(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    __o->store(__d);
+}
+
+// atomic_store_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void
+atomic_store_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
+  _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
+{
+    __o->store(__d, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+void
+atomic_store_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
+  _LIBCPP_CHECK_STORE_MEMORY_ORDER(__m)
+{
+    __o->store(__d, __m);
+}
+
+// atomic_load
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_load(const volatile atomic<_Tp>* __o) _NOEXCEPT
+{
+    return __o->load();
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_load(const atomic<_Tp>* __o) _NOEXCEPT
+{
+    return __o->load();
+}
+
+// atomic_load_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_load_explicit(const volatile atomic<_Tp>* __o, memory_order __m) _NOEXCEPT
+  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
+{
+    return __o->load(__m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_load_explicit(const atomic<_Tp>* __o, memory_order __m) _NOEXCEPT
+  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
+{
+    return __o->load(__m);
+}
+
+// atomic_exchange
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_exchange(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    return __o->exchange(__d);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_exchange(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    return __o->exchange(__d);
+}
+
+// atomic_exchange_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_exchange_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
+{
+    return __o->exchange(__d, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_exchange_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __d, memory_order __m) _NOEXCEPT
+{
+    return __o->exchange(__d, __m);
+}
+
+// atomic_compare_exchange_weak
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_weak(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    return __o->compare_exchange_weak(*__e, __d);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_weak(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    return __o->compare_exchange_weak(*__e, __d);
+}
+
+// atomic_compare_exchange_strong
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_strong(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    return __o->compare_exchange_strong(*__e, __d);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_strong(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d) _NOEXCEPT
+{
+    return __o->compare_exchange_strong(*__e, __d);
+}
+
+// atomic_compare_exchange_weak_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_weak_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e,
+                                      typename atomic<_Tp>::value_type __d,
+                                      memory_order __s, memory_order __f) _NOEXCEPT
+  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+{
+    return __o->compare_exchange_weak(*__e, __d, __s, __f);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_weak_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d,
+                                      memory_order __s, memory_order __f) _NOEXCEPT
+  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+{
+    return __o->compare_exchange_weak(*__e, __d, __s, __f);
+}
+
+// atomic_compare_exchange_strong_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_strong_explicit(volatile atomic<_Tp>* __o,
+                                        typename atomic<_Tp>::value_type* __e, typename atomic<_Tp>::value_type __d,
+                                        memory_order __s, memory_order __f) _NOEXCEPT
+  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+{
+    return __o->compare_exchange_strong(*__e, __d, __s, __f);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+atomic_compare_exchange_strong_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type* __e,
+                                        typename atomic<_Tp>::value_type __d,
+                                        memory_order __s, memory_order __f) _NOEXCEPT
+  _LIBCPP_CHECK_EXCHANGE_MEMORY_ORDER(__s, __f)
+{
+    return __o->compare_exchange_strong(*__e, __d, __s, __f);
+}
+
+// atomic_wait
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_wait(const volatile atomic<_Tp>* __o,
+                 typename atomic<_Tp>::value_type __v) _NOEXCEPT
+{
+    return __o->wait(__v);
+}
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_wait(const atomic<_Tp>* __o,
+                 typename atomic<_Tp>::value_type __v) _NOEXCEPT
+{
+    return __o->wait(__v);
+}
+
+// atomic_wait_explicit
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_wait_explicit(const volatile atomic<_Tp>* __o,
+                          typename atomic<_Tp>::value_type __v,
+                          memory_order __m) _NOEXCEPT
+  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
+{
+    return __o->wait(__v, __m);
+}
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_wait_explicit(const atomic<_Tp>* __o,
+                          typename atomic<_Tp>::value_type __v,
+                          memory_order __m) _NOEXCEPT
+  _LIBCPP_CHECK_LOAD_MEMORY_ORDER(__m)
+{
+    return __o->wait(__v, __m);
+}
+
+// atomic_notify_one
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_notify_one(volatile atomic<_Tp>* __o) _NOEXCEPT
+{
+    __o->notify_one();
+}
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_notify_one(atomic<_Tp>* __o) _NOEXCEPT
+{
+    __o->notify_one();
+}
+
+// atomic_notify_one
+
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_notify_all(volatile atomic<_Tp>* __o) _NOEXCEPT
+{
+    __o->notify_all();
+}
+template <class _Tp>
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+void atomic_notify_all(atomic<_Tp>* __o) _NOEXCEPT
+{
+    __o->notify_all();
+}
+
+// atomic_fetch_add
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_fetch_add(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
+{
+    return __o->fetch_add(__op);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp
+atomic_fetch_add(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
+{
+    return __o->fetch_add(__op);
+}
+
+// atomic_fetch_add_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp atomic_fetch_add_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_add(__op, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp atomic_fetch_add_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_add(__op, __m);
+}
+
+// atomic_fetch_sub
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp atomic_fetch_sub(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
+{
+    return __o->fetch_sub(__op);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp atomic_fetch_sub(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op) _NOEXCEPT
+{
+    return __o->fetch_sub(__op);
+}
+
+// atomic_fetch_sub_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp atomic_fetch_sub_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_sub(__op, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp atomic_fetch_sub_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::difference_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_sub(__op, __m);
+}
+
+// atomic_fetch_and
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_and(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
+{
+    return __o->fetch_and(__op);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_and(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
+{
+    return __o->fetch_and(__op);
+}
+
+// atomic_fetch_and_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_and_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_and(__op, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_and_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_and(__op, __m);
+}
+
+// atomic_fetch_or
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_or(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
+{
+    return __o->fetch_or(__op);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_or(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
+{
+    return __o->fetch_or(__op);
+}
+
+// atomic_fetch_or_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_or_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_or(__op, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_or_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_or(__op, __m);
+}
+
+// atomic_fetch_xor
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_xor(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
+{
+    return __o->fetch_xor(__op);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_xor(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op) _NOEXCEPT
+{
+    return __o->fetch_xor(__op);
+}
+
+// atomic_fetch_xor_explicit
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_xor_explicit(volatile atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_xor(__op, __m);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value && !is_same<_Tp, bool>::value,
+    _Tp
+>::type
+atomic_fetch_xor_explicit(atomic<_Tp>* __o, typename atomic<_Tp>::value_type __op, memory_order __m) _NOEXCEPT
+{
+    return __o->fetch_xor(__op, __m);
+}
+
+// flag type and operations
+
+typedef struct atomic_flag
+{
+    __cxx_atomic_impl<_LIBCPP_ATOMIC_FLAG_TYPE> __a_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool test(memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
+        {return _LIBCPP_ATOMIC_FLAG_TYPE(true) == __cxx_atomic_load(&__a_, __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool test(memory_order __m = memory_order_seq_cst) const _NOEXCEPT
+        {return _LIBCPP_ATOMIC_FLAG_TYPE(true) == __cxx_atomic_load(&__a_, __m);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool test_and_set(memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool test_and_set(memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear(memory_order __m = memory_order_seq_cst) volatile _NOEXCEPT
+        {__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear(memory_order __m = memory_order_seq_cst) _NOEXCEPT
+        {__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
+
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void wait(bool __v, memory_order __m = memory_order_seq_cst) const volatile _NOEXCEPT
+        {__cxx_atomic_wait(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(__v), __m);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void wait(bool __v, memory_order __m = memory_order_seq_cst) const _NOEXCEPT
+        {__cxx_atomic_wait(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(__v), __m);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void notify_one() volatile _NOEXCEPT
+        {__cxx_atomic_notify_one(&__a_);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void notify_one() _NOEXCEPT
+        {__cxx_atomic_notify_one(&__a_);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void notify_all() volatile _NOEXCEPT
+        {__cxx_atomic_notify_all(&__a_);}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void notify_all() _NOEXCEPT
+        {__cxx_atomic_notify_all(&__a_);}
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY constexpr
+    atomic_flag() _NOEXCEPT : __a_(false) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    atomic_flag() _NOEXCEPT _LIBCPP_DEFAULT
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    atomic_flag(bool __b) _NOEXCEPT : __a_(__b) {} // EXTENSION
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4522 )
+#endif
+#ifndef _LIBCPP_CXX03_LANG
+    atomic_flag(const atomic_flag&) = delete;
+    atomic_flag& operator=(const atomic_flag&) = delete;
+    atomic_flag& operator=(const atomic_flag&) volatile = delete;
+#else
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    atomic_flag(const atomic_flag&);
+    _LIBCPP_INLINE_VISIBILITY
+    atomic_flag& operator=(const atomic_flag&);
+    _LIBCPP_INLINE_VISIBILITY
+    atomic_flag& operator=(const atomic_flag&) volatile;
+#endif
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+} atomic_flag;
+
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test(const volatile atomic_flag* __o) _NOEXCEPT
+{
+    return __o->test();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test(const atomic_flag* __o) _NOEXCEPT
+{
+    return __o->test();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test_explicit(const volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
+{
+    return __o->test(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test_explicit(const atomic_flag* __o, memory_order __m) _NOEXCEPT
+{
+    return __o->test(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test_and_set(volatile atomic_flag* __o) _NOEXCEPT
+{
+    return __o->test_and_set();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test_and_set(atomic_flag* __o) _NOEXCEPT
+{
+    return __o->test_and_set();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test_and_set_explicit(volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
+{
+    return __o->test_and_set(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+atomic_flag_test_and_set_explicit(atomic_flag* __o, memory_order __m) _NOEXCEPT
+{
+    return __o->test_and_set(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+atomic_flag_clear(volatile atomic_flag* __o) _NOEXCEPT
+{
+    __o->clear();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+atomic_flag_clear(atomic_flag* __o) _NOEXCEPT
+{
+    __o->clear();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+atomic_flag_clear_explicit(volatile atomic_flag* __o, memory_order __m) _NOEXCEPT
+{
+    __o->clear(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+atomic_flag_clear_explicit(atomic_flag* __o, memory_order __m) _NOEXCEPT
+{
+    __o->clear(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_wait(const volatile atomic_flag* __o, bool __v) _NOEXCEPT
+{
+    __o->wait(__v);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_wait(const atomic_flag* __o, bool __v) _NOEXCEPT
+{
+    __o->wait(__v);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_wait_explicit(const volatile atomic_flag* __o,
+                          bool __v, memory_order __m) _NOEXCEPT
+{
+    __o->wait(__v, __m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_wait_explicit(const atomic_flag* __o,
+                          bool __v, memory_order __m) _NOEXCEPT
+{
+    __o->wait(__v, __m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_notify_one(volatile atomic_flag* __o) _NOEXCEPT
+{
+    __o->notify_one();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_notify_one(atomic_flag* __o) _NOEXCEPT
+{
+    __o->notify_one();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_notify_all(volatile atomic_flag* __o) _NOEXCEPT
+{
+    __o->notify_all();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_AVAILABILITY_SYNC
+void
+atomic_flag_notify_all(atomic_flag* __o) _NOEXCEPT
+{
+    __o->notify_all();
+}
+
+// fences
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+atomic_thread_fence(memory_order __m) _NOEXCEPT
+{
+    __cxx_atomic_thread_fence(__m);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+atomic_signal_fence(memory_order __m) _NOEXCEPT
+{
+    __cxx_atomic_signal_fence(__m);
+}
+
+// Atomics for standard typedef types
+
+typedef atomic<bool>               atomic_bool;
+typedef atomic<char>               atomic_char;
+typedef atomic<signed char>        atomic_schar;
+typedef atomic<unsigned char>      atomic_uchar;
+typedef atomic<short>              atomic_short;
+typedef atomic<unsigned short>     atomic_ushort;
+typedef atomic<int>                atomic_int;
+typedef atomic<unsigned int>       atomic_uint;
+typedef atomic<long>               atomic_long;
+typedef atomic<unsigned long>      atomic_ulong;
+typedef atomic<long long>          atomic_llong;
+typedef atomic<unsigned long long> atomic_ullong;
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+typedef atomic<char8_t>            atomic_char8_t;
+#endif
+typedef atomic<char16_t>           atomic_char16_t;
+typedef atomic<char32_t>           atomic_char32_t;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef atomic<wchar_t>            atomic_wchar_t;
+#endif
+
+typedef atomic<int_least8_t>   atomic_int_least8_t;
+typedef atomic<uint_least8_t>  atomic_uint_least8_t;
+typedef atomic<int_least16_t>  atomic_int_least16_t;
+typedef atomic<uint_least16_t> atomic_uint_least16_t;
+typedef atomic<int_least32_t>  atomic_int_least32_t;
+typedef atomic<uint_least32_t> atomic_uint_least32_t;
+typedef atomic<int_least64_t>  atomic_int_least64_t;
+typedef atomic<uint_least64_t> atomic_uint_least64_t;
+
+typedef atomic<int_fast8_t>   atomic_int_fast8_t;
+typedef atomic<uint_fast8_t>  atomic_uint_fast8_t;
+typedef atomic<int_fast16_t>  atomic_int_fast16_t;
+typedef atomic<uint_fast16_t> atomic_uint_fast16_t;
+typedef atomic<int_fast32_t>  atomic_int_fast32_t;
+typedef atomic<uint_fast32_t> atomic_uint_fast32_t;
+typedef atomic<int_fast64_t>  atomic_int_fast64_t;
+typedef atomic<uint_fast64_t> atomic_uint_fast64_t;
+
+typedef atomic< int8_t>  atomic_int8_t;
+typedef atomic<uint8_t>  atomic_uint8_t;
+typedef atomic< int16_t> atomic_int16_t;
+typedef atomic<uint16_t> atomic_uint16_t;
+typedef atomic< int32_t> atomic_int32_t;
+typedef atomic<uint32_t> atomic_uint32_t;
+typedef atomic< int64_t> atomic_int64_t;
+typedef atomic<uint64_t> atomic_uint64_t;
+
+typedef atomic<intptr_t>  atomic_intptr_t;
+typedef atomic<uintptr_t> atomic_uintptr_t;
+typedef atomic<size_t>    atomic_size_t;
+typedef atomic<ptrdiff_t> atomic_ptrdiff_t;
+typedef atomic<intmax_t>  atomic_intmax_t;
+typedef atomic<uintmax_t> atomic_uintmax_t;
+
+// atomic_*_lock_free : prefer the contention type most highly, then the largest lock-free type
+
+#ifdef __cpp_lib_atomic_is_always_lock_free
+# define _LIBCPP_CONTENTION_LOCK_FREE __atomic_always_lock_free(sizeof(__cxx_contention_t), 0)
+#else
+# define _LIBCPP_CONTENTION_LOCK_FREE false
+#endif
+
+#if ATOMIC_LLONG_LOCK_FREE == 2
+typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, long long>::type          __libcpp_signed_lock_free;
+typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned long long>::type __libcpp_unsigned_lock_free;
+#elif ATOMIC_INT_LOCK_FREE == 2
+typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, int>::type                __libcpp_signed_lock_free;
+typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned int>::type       __libcpp_unsigned_lock_free;
+#elif ATOMIC_SHORT_LOCK_FREE == 2
+typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, short>::type              __libcpp_signed_lock_free;
+typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned short>::type     __libcpp_unsigned_lock_free;
+#elif ATOMIC_CHAR_LOCK_FREE == 2
+typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, char>::type               __libcpp_signed_lock_free;
+typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned char>::type      __libcpp_unsigned_lock_free;
+#else
+    // No signed/unsigned lock-free types
+#endif
+
+typedef atomic<__libcpp_signed_lock_free> atomic_signed_lock_free;
+typedef atomic<__libcpp_unsigned_lock_free> atomic_unsigned_lock_free;
+
+#define ATOMIC_FLAG_INIT {false}
+#define ATOMIC_VAR_INIT(__v) {__v}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_ATOMIC
diff --git a/contrib/libs/cxxsupp/libcxx/include/barrier b/contrib/libs/cxxsupp/libcxx/include/barrier
new file mode 100644
index 00000000000..c40a1e43f31
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/barrier
@@ -0,0 +1,329 @@
+// -*- C++ -*-
+//===--------------------------- barrier ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_BARRIER
+#define _LIBCPP_BARRIER
+
+/*
+    barrier synopsis
+
+namespace std
+{
+
+  template<class CompletionFunction = see below>
+  class barrier
+  {
+  public:
+    using arrival_token = see below;
+
+    static constexpr ptrdiff_t max() noexcept;
+
+    constexpr explicit barrier(ptrdiff_t phase_count,
+                               CompletionFunction f = CompletionFunction());
+    ~barrier();
+
+    barrier(const barrier&) = delete;
+    barrier& operator=(const barrier&) = delete;
+
+    [[nodiscard]] arrival_token arrive(ptrdiff_t update = 1);
+    void wait(arrival_token&& arrival) const;
+
+    void arrive_and_wait();
+    void arrive_and_drop();
+
+  private:
+    CompletionFunction completion; // exposition only
+  };
+
+}
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <atomic>
+#ifndef _LIBCPP_HAS_NO_TREE_BARRIER
+# include <memory>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_HAS_NO_THREADS
+# error <barrier> is not supported on this single threaded system
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#if _LIBCPP_STD_VER >= 14
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+struct __empty_completion
+{
+    inline _LIBCPP_INLINE_VISIBILITY
+    void operator()() noexcept
+    {
+    }
+};
+
+#ifndef _LIBCPP_HAS_NO_TREE_BARRIER
+
+/*
+
+The default implementation of __barrier_base is a classic tree barrier.
+
+It looks different from literature pseudocode for two main reasons:
+ 1. Threads that call into std::barrier functions do not provide indices,
+    so a numbering step is added before the actual barrier algorithm,
+    appearing as an N+1 round to the N rounds of the tree barrier.
+ 2. A great deal of attention has been paid to avoid cache line thrashing
+    by flattening the tree structure into cache-line sized arrays, that
+    are indexed in an efficient way.
+
+*/
+
+using __barrier_phase_t = uint8_t;
+
+class __barrier_algorithm_base;
+
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI
+__barrier_algorithm_base* __construct_barrier_algorithm_base(ptrdiff_t& __expected);
+
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI
+bool __arrive_barrier_algorithm_base(__barrier_algorithm_base* __barrier,
+                                     __barrier_phase_t __old_phase);
+
+_LIBCPP_AVAILABILITY_SYNC _LIBCPP_EXPORTED_FROM_ABI
+void __destroy_barrier_algorithm_base(__barrier_algorithm_base* __barrier);
+
+template<class _CompletionF>
+class __barrier_base {
+    ptrdiff_t                                               __expected;
+    unique_ptr<__barrier_algorithm_base,
+               void (*)(__barrier_algorithm_base*)>         __base;
+    __atomic_base<ptrdiff_t>                                __expected_adjustment;
+    _CompletionF                                            __completion;
+    __atomic_base<__barrier_phase_t>                        __phase;
+
+public:
+    using arrival_token = __barrier_phase_t;
+
+    static constexpr ptrdiff_t max() noexcept {
+        return numeric_limits<ptrdiff_t>::max();
+    }
+
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    __barrier_base(ptrdiff_t __expected, _CompletionF __completion = _CompletionF())
+            : __expected(__expected), __base(__construct_barrier_algorithm_base(this->__expected),
+                                             &__destroy_barrier_algorithm_base),
+              __expected_adjustment(0), __completion(move(__completion)), __phase(0)
+    {
+    }
+    [[nodiscard]] _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    arrival_token arrive(ptrdiff_t update)
+    {
+        auto const __old_phase = __phase.load(memory_order_relaxed);
+        for(; update; --update)
+            if(__arrive_barrier_algorithm_base(__base.get(), __old_phase)) {
+                __completion();
+                __expected += __expected_adjustment.load(memory_order_relaxed);
+                __expected_adjustment.store(0, memory_order_relaxed);
+                __phase.store(__old_phase + 2, memory_order_release);
+                __phase.notify_all();
+            }
+        return __old_phase;
+    }
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void wait(arrival_token&& __old_phase) const
+    {
+        auto const __test_fn = [this, __old_phase]() -> bool {
+            return __phase.load(memory_order_acquire) != __old_phase;
+        };
+        __libcpp_thread_poll_with_backoff(__test_fn, __libcpp_timed_backoff_policy());
+    }
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void arrive_and_drop()
+    {
+        __expected_adjustment.fetch_sub(1, memory_order_relaxed);
+        (void)arrive(1);
+    }
+};
+
+#else
+
+/*
+
+The alternative implementation of __barrier_base is a central barrier.
+
+Two versions of this algorithm are provided:
+ 1. A fairly straightforward implementation of the litterature for the
+    general case where the completion function is not empty.
+ 2. An optimized implementation that exploits 2's complement arithmetic
+    and well-defined overflow in atomic arithmetic, to handle the phase
+    roll-over for free.
+
+*/
+
+template<class _CompletionF>
+class __barrier_base {
+
+    __atomic_base<ptrdiff_t> __expected;
+    __atomic_base<ptrdiff_t> __arrived;
+    _CompletionF             __completion;
+    __atomic_base<bool>      __phase;
+public:
+    using arrival_token = bool;
+
+    static constexpr ptrdiff_t max() noexcept {
+        return numeric_limits<ptrdiff_t>::max();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __barrier_base(ptrdiff_t __expected, _CompletionF __completion = _CompletionF())
+        : __expected(__expected), __arrived(__expected), __completion(move(__completion)), __phase(false)
+    {
+    }
+    [[nodiscard]] _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    arrival_token arrive(ptrdiff_t update)
+    {
+        auto const __old_phase = __phase.load(memory_order_relaxed);
+        auto const __result = __arrived.fetch_sub(update, memory_order_acq_rel) - update;
+        auto const new_expected = __expected.load(memory_order_relaxed);
+        if(0 == __result) {
+            __completion();
+            __arrived.store(new_expected, memory_order_relaxed);
+            __phase.store(!__old_phase, memory_order_release);
+            __phase.notify_all();
+        }
+        return __old_phase;
+    }
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void wait(arrival_token&& __old_phase) const
+    {
+        __phase.wait(__old_phase, memory_order_acquire);
+    }
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void arrive_and_drop()
+    {
+        __expected.fetch_sub(1, memory_order_relaxed);
+        (void)arrive(1);
+    }
+};
+
+template<>
+class __barrier_base<__empty_completion> {
+
+    static constexpr uint64_t __expected_unit = 1ull;
+    static constexpr uint64_t __arrived_unit = 1ull << 32;
+    static constexpr uint64_t __expected_mask = __arrived_unit - 1;
+    static constexpr uint64_t __phase_bit = 1ull << 63;
+    static constexpr uint64_t __arrived_mask = (__phase_bit - 1) & ~__expected_mask;
+
+    __atomic_base<uint64_t>   __phase_arrived_expected;
+
+    static _LIBCPP_INLINE_VISIBILITY
+    constexpr uint64_t __init(ptrdiff_t __count) _NOEXCEPT
+    {
+        return ((uint64_t(1u << 31) - __count) << 32)
+              | (uint64_t(1u << 31) - __count);
+    }
+
+public:
+    using arrival_token = uint64_t;
+
+    static constexpr ptrdiff_t max() noexcept {
+        return ptrdiff_t(1u << 31) - 1;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit inline __barrier_base(ptrdiff_t __count, __empty_completion = __empty_completion())
+        : __phase_arrived_expected(__init(__count))
+    {
+    }
+    [[nodiscard]] inline _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    arrival_token arrive(ptrdiff_t update)
+    {
+        auto const __inc = __arrived_unit * update;
+        auto const __old = __phase_arrived_expected.fetch_add(__inc, memory_order_acq_rel);
+        if((__old ^ (__old + __inc)) & __phase_bit) {
+            __phase_arrived_expected.fetch_add((__old & __expected_mask) << 32, memory_order_relaxed);
+            __phase_arrived_expected.notify_all();
+        }
+        return __old & __phase_bit;
+    }
+    inline _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void wait(arrival_token&& __phase) const
+    {
+        auto const __test_fn = [=]() -> bool {
+            uint64_t const __current = __phase_arrived_expected.load(memory_order_acquire);
+            return ((__current & __phase_bit) != __phase);
+        };
+        __libcpp_thread_poll_with_backoff(__test_fn, __libcpp_timed_backoff_policy());
+    }
+    inline _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void arrive_and_drop()
+    {
+        __phase_arrived_expected.fetch_add(__expected_unit, memory_order_relaxed);
+        (void)arrive(1);
+    }
+};
+
+#endif //_LIBCPP_HAS_NO_TREE_BARRIER
+
+template<class _CompletionF = __empty_completion>
+class barrier {
+
+    __barrier_base<_CompletionF> __b;
+public:
+    using arrival_token = typename __barrier_base<_CompletionF>::arrival_token;
+
+    static constexpr ptrdiff_t max() noexcept {
+        return __barrier_base<_CompletionF>::max();
+    }
+
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    barrier(ptrdiff_t __count, _CompletionF __completion = _CompletionF())
+        : __b(__count, _VSTD::move(__completion)) {
+    }
+
+    barrier(barrier const&) = delete;
+    barrier& operator=(barrier const&) = delete;
+
+    [[nodiscard]] _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    arrival_token arrive(ptrdiff_t update = 1)
+    {
+        return __b.arrive(update);
+    }
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void wait(arrival_token&& __phase) const
+    {
+        __b.wait(_VSTD::move(__phase));
+    }
+	_LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void arrive_and_wait()
+    {
+        wait(arrive());
+	}
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void arrive_and_drop()
+    {
+        __b.arrive_and_drop();
+    }
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 14
+
+_LIBCPP_POP_MACROS
+
+#endif //_LIBCPP_BARRIER
diff --git a/contrib/libs/cxxsupp/libcxx/include/bit b/contrib/libs/cxxsupp/libcxx/include/bit
new file mode 100644
index 00000000000..eab67977a19
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/bit
@@ -0,0 +1,345 @@
+// -*- C++ -*-
+//===------------------------------ bit ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===---------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_BIT
+#define _LIBCPP_BIT
+
+/*
+    bit synopsis
+
+namespace std {
+    // [bit.cast], bit_cast
+    template<class To, class From>
+      constexpr To bit_cast(const From& from) noexcept; // C++20
+
+  // [bit.pow.two], integral powers of 2
+  template <class T>
+    constexpr bool has_single_bit(T x) noexcept; // C++20
+  template <class T>
+    constexpr T bit_ceil(T x);                   // C++20
+  template <class T>
+    constexpr T bit_floor(T x) noexcept;         // C++20
+  template <class T>
+    constexpr T bit_width(T x) noexcept;         // C++20
+
+  // [bit.rotate], rotating
+  template<class T>
+    constexpr T rotl(T x, unsigned int s) noexcept; // C++20
+  template<class T>
+    constexpr T rotr(T x, unsigned int s) noexcept; // C++20
+
+  // [bit.count], counting
+  template<class T>
+    constexpr int countl_zero(T x) noexcept;  // C++20
+  template<class T>
+    constexpr int countl_one(T x) noexcept;   // C++20
+  template<class T>
+    constexpr int countr_zero(T x) noexcept;  // C++20
+  template<class T>
+    constexpr int countr_one(T x) noexcept;   // C++20
+  template<class T>
+    constexpr int popcount(T x) noexcept;     // C++20
+
+  // [bit.endian], endian
+  enum class endian {
+    little = see below,        // C++20
+    big = see below,           // C++20
+    native = see below         // C++20
+};
+
+} // namespace std
+
+*/
+
+#include <__bit/bit_cast.h>
+#include <__bits> // __libcpp_clz
+#include <__config>
+#include <__debug>
+#include <limits>
+#include <type_traits>
+#include <version>
+
+#if defined(__IBMCPP__)
+#include "__support/ibm/support.h"
+#endif
+#if defined(_LIBCPP_COMPILER_MSVC)
+#include <intrin.h>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp __rotl(_Tp __t, unsigned int __cnt) _NOEXCEPT
+{
+    static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__rotl requires an unsigned integer type");
+    const unsigned int __dig = numeric_limits<_Tp>::digits;
+    if ((__cnt % __dig) == 0)
+        return __t;
+    return (__t << (__cnt % __dig)) | (__t >> (__dig - (__cnt % __dig)));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp __rotr(_Tp __t, unsigned int __cnt) _NOEXCEPT
+{
+    static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__rotr requires an unsigned integer type");
+    const unsigned int __dig = numeric_limits<_Tp>::digits;
+    if ((__cnt % __dig) == 0)
+        return __t;
+    return (__t >> (__cnt % __dig)) | (__t << (__dig - (__cnt % __dig)));
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+int __countr_zero(_Tp __t) _NOEXCEPT
+{
+    static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__countr_zero requires an unsigned integer type");
+    if (__t == 0)
+        return numeric_limits<_Tp>::digits;
+
+    if      (sizeof(_Tp) <= sizeof(unsigned int))
+        return __libcpp_ctz(static_cast<unsigned int>(__t));
+    else if (sizeof(_Tp) <= sizeof(unsigned long))
+        return __libcpp_ctz(static_cast<unsigned long>(__t));
+    else if (sizeof(_Tp) <= sizeof(unsigned long long))
+        return __libcpp_ctz(static_cast<unsigned long long>(__t));
+    else
+    {
+        int __ret = 0;
+        const unsigned int __ulldigits = numeric_limits<unsigned long long>::digits;
+        while (static_cast<unsigned long long>(__t) == 0uLL)
+        {
+            __ret += __ulldigits;
+            __t >>= __ulldigits;
+        }
+        return __ret + __libcpp_ctz(static_cast<unsigned long long>(__t));
+    }
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+int __countl_zero(_Tp __t) _NOEXCEPT
+{
+    static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__countl_zero requires an unsigned integer type");
+    if (__t == 0)
+        return numeric_limits<_Tp>::digits;
+
+    if      (sizeof(_Tp) <= sizeof(unsigned int))
+        return __libcpp_clz(static_cast<unsigned int>(__t))
+              - (numeric_limits<unsigned int>::digits - numeric_limits<_Tp>::digits);
+    else if (sizeof(_Tp) <= sizeof(unsigned long))
+        return __libcpp_clz(static_cast<unsigned long>(__t))
+              - (numeric_limits<unsigned long>::digits - numeric_limits<_Tp>::digits);
+    else if (sizeof(_Tp) <= sizeof(unsigned long long))
+        return __libcpp_clz(static_cast<unsigned long long>(__t))
+              - (numeric_limits<unsigned long long>::digits - numeric_limits<_Tp>::digits);
+    else
+    {
+        int __ret = 0;
+        int __iter = 0;
+        const unsigned int __ulldigits = numeric_limits<unsigned long long>::digits;
+        while (true) {
+            __t = __rotr(__t, __ulldigits);
+            if ((__iter = __countl_zero(static_cast<unsigned long long>(__t))) != __ulldigits)
+                break;
+            __ret += __iter;
+            }
+        return __ret + __iter;
+    }
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+int __countl_one(_Tp __t) _NOEXCEPT
+{
+    static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__countl_one requires an unsigned integer type");
+    return __t != numeric_limits<_Tp>::max()
+        ? __countl_zero(static_cast<_Tp>(~__t))
+        : numeric_limits<_Tp>::digits;
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+int __countr_one(_Tp __t) _NOEXCEPT
+{
+    static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__countr_one requires an unsigned integer type");
+    return __t != numeric_limits<_Tp>::max()
+        ? __countr_zero(static_cast<_Tp>(~__t))
+        : numeric_limits<_Tp>::digits;
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+int __popcount(_Tp __t) _NOEXCEPT
+{
+    static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__popcount requires an unsigned integer type");
+    if      (sizeof(_Tp) <= sizeof(unsigned int))
+        return __libcpp_popcount(static_cast<unsigned int>(__t));
+    else if (sizeof(_Tp) <= sizeof(unsigned long))
+        return __libcpp_popcount(static_cast<unsigned long>(__t));
+    else if (sizeof(_Tp) <= sizeof(unsigned long long))
+        return __libcpp_popcount(static_cast<unsigned long long>(__t));
+    else
+    {
+        int __ret = 0;
+        while (__t != 0)
+        {
+            __ret += __libcpp_popcount(static_cast<unsigned long long>(__t));
+            __t >>= numeric_limits<unsigned long long>::digits;
+        }
+        return __ret;
+    }
+}
+
+// integral log base 2
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+unsigned __bit_log2(_Tp __t) _NOEXCEPT
+{
+    static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__bit_log2 requires an unsigned integer type");
+    return numeric_limits<_Tp>::digits - 1 - __countl_zero(__t);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+bool __has_single_bit(_Tp __t) _NOEXCEPT
+{
+    static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__has_single_bit requires an unsigned integer type");
+    return __t != 0 && (((__t & (__t - 1)) == 0));
+}
+
+#if _LIBCPP_STD_VER > 17
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, _Tp>
+rotl(_Tp __t, unsigned int __cnt) noexcept
+{
+    return __rotl(__t, __cnt);
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, _Tp>
+rotr(_Tp __t, unsigned int __cnt) noexcept
+{
+    return __rotr(__t, __cnt);
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, int>
+countl_zero(_Tp __t) noexcept
+{
+    return __countl_zero(__t);
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, int>
+countl_one(_Tp __t) noexcept
+{
+    return __countl_one(__t);
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, int>
+countr_zero(_Tp __t) noexcept
+{
+    return __countr_zero(__t);
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, int>
+countr_one(_Tp __t) noexcept
+{
+    return __countr_one(__t);
+}
+
+template<class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, int>
+popcount(_Tp __t) noexcept
+{
+    return __popcount(__t);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, bool>
+has_single_bit(_Tp __t) noexcept
+{
+    return __has_single_bit(__t);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, _Tp>
+bit_floor(_Tp __t) noexcept
+{
+    return __t == 0 ? 0 : _Tp{1} << __bit_log2(__t);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, _Tp>
+bit_ceil(_Tp __t) noexcept
+{
+    if (__t < 2) return 1;
+    const unsigned __n = numeric_limits<_Tp>::digits - countl_zero((_Tp)(__t - 1u));
+    _LIBCPP_DEBUG_ASSERT(__libcpp_is_constant_evaluated() || __n != numeric_limits<_Tp>::digits, "Bad input to bit_ceil");
+
+    if constexpr (sizeof(_Tp) >= sizeof(unsigned))
+        return _Tp{1} << __n;
+    else
+    {
+        const unsigned __extra = numeric_limits<unsigned>::digits  - numeric_limits<_Tp>::digits;
+        const unsigned __retVal = 1u << (__n + __extra);
+        return (_Tp) (__retVal >> __extra);
+    }
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<__libcpp_is_unsigned_integer<_Tp>::value, _Tp>
+bit_width(_Tp __t) noexcept
+{
+    return __t == 0 ? 0 : __bit_log2(__t) + 1;
+}
+
+enum class endian
+{
+    little = 0xDEAD,
+    big    = 0xFACE,
+#if defined(_LIBCPP_LITTLE_ENDIAN)
+    native = little
+#elif defined(_LIBCPP_BIG_ENDIAN)
+    native = big
+#else
+    native = 0xCAFE
+#endif
+};
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_BIT
diff --git a/contrib/libs/cxxsupp/libcxx/include/bitset b/contrib/libs/cxxsupp/libcxx/include/bitset
new file mode 100644
index 00000000000..9f58bbcd379
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/bitset
@@ -0,0 +1,1107 @@
+// -*- C++ -*-
+//===---------------------------- bitset ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_BITSET
+#define _LIBCPP_BITSET
+
+/*
+    bitset synopsis
+
+namespace std
+{
+
+namespace std {
+
+template <size_t N>
+class bitset
+{
+public:
+    // bit reference:
+    class reference
+    {
+        friend class bitset;
+        reference() noexcept;
+    public:
+        ~reference() noexcept;
+        reference& operator=(bool x) noexcept;           // for b[i] = x;
+        reference& operator=(const reference&) noexcept; // for b[i] = b[j];
+        bool operator~() const noexcept;                 // flips the bit
+        operator bool() const noexcept;                  // for x = b[i];
+        reference& flip() noexcept;                      // for b[i].flip();
+    };
+
+    // 23.3.5.1 constructors:
+    constexpr bitset() noexcept;
+    constexpr bitset(unsigned long long val) noexcept;
+    template <class charT>
+        explicit bitset(const charT* str,
+                        typename basic_string<charT>::size_type n = basic_string<charT>::npos,
+                        charT zero = charT('0'), charT one = charT('1'));
+    template<class charT, class traits, class Allocator>
+        explicit bitset(const basic_string<charT,traits,Allocator>& str,
+                        typename basic_string<charT,traits,Allocator>::size_type pos = 0,
+                        typename basic_string<charT,traits,Allocator>::size_type n =
+                                 basic_string<charT,traits,Allocator>::npos,
+                        charT zero = charT('0'), charT one = charT('1'));
+
+    // 23.3.5.2 bitset operations:
+    bitset& operator&=(const bitset& rhs) noexcept;
+    bitset& operator|=(const bitset& rhs) noexcept;
+    bitset& operator^=(const bitset& rhs) noexcept;
+    bitset& operator<<=(size_t pos) noexcept;
+    bitset& operator>>=(size_t pos) noexcept;
+    bitset& set() noexcept;
+    bitset& set(size_t pos, bool val = true);
+    bitset& reset() noexcept;
+    bitset& reset(size_t pos);
+    bitset operator~() const noexcept;
+    bitset& flip() noexcept;
+    bitset& flip(size_t pos);
+
+    // element access:
+    constexpr bool operator[](size_t pos) const; // for b[i];
+    reference operator[](size_t pos);            // for b[i];
+    unsigned long to_ulong() const;
+    unsigned long long to_ullong() const;
+    template <class charT, class traits, class Allocator>
+        basic_string<charT, traits, Allocator> to_string(charT zero = charT('0'), charT one = charT('1')) const;
+    template <class charT, class traits>
+        basic_string<charT, traits, allocator<charT> > to_string(charT zero = charT('0'), charT one = charT('1')) const;
+    template <class charT>
+        basic_string<charT, char_traits<charT>, allocator<charT> > to_string(charT zero = charT('0'), charT one = charT('1')) const;
+    basic_string<char, char_traits<char>, allocator<char> > to_string(char zero = '0', char one = '1') const;
+    size_t count() const noexcept;
+    constexpr size_t size() const noexcept;
+    bool operator==(const bitset& rhs) const noexcept;
+    bool operator!=(const bitset& rhs) const noexcept;
+    bool test(size_t pos) const;
+    bool all() const noexcept;
+    bool any() const noexcept;
+    bool none() const noexcept;
+    bitset operator<<(size_t pos) const noexcept;
+    bitset operator>>(size_t pos) const noexcept;
+};
+
+// 23.3.5.3 bitset operators:
+template <size_t N>
+bitset<N> operator&(const bitset<N>&, const bitset<N>&) noexcept;
+
+template <size_t N>
+bitset<N> operator|(const bitset<N>&, const bitset<N>&) noexcept;
+
+template <size_t N>
+bitset<N> operator^(const bitset<N>&, const bitset<N>&) noexcept;
+
+template <class charT, class traits, size_t N>
+basic_istream<charT, traits>&
+operator>>(basic_istream<charT, traits>& is, bitset<N>& x);
+
+template <class charT, class traits, size_t N>
+basic_ostream<charT, traits>&
+operator<<(basic_ostream<charT, traits>& os, const bitset<N>& x);
+
+template <size_t N> struct hash<std::bitset<N>>;
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__bit_reference>
+#include <__functional_base>
+#include <climits>
+#include <cstddef>
+#include <iosfwd>
+#include <stdexcept>
+#include <string>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <size_t _N_words, size_t _Size>
+class __bitset;
+
+template <size_t _N_words, size_t _Size>
+struct __has_storage_type<__bitset<_N_words, _Size> >
+{
+    static const bool value = true;
+};
+
+template <size_t _N_words, size_t _Size>
+class __bitset
+{
+public:
+    typedef ptrdiff_t              difference_type;
+    typedef size_t                 size_type;
+    typedef size_type              __storage_type;
+protected:
+    typedef __bitset __self;
+    typedef       __storage_type*  __storage_pointer;
+    typedef const __storage_type*  __const_storage_pointer;
+    static const unsigned __bits_per_word = static_cast<unsigned>(sizeof(__storage_type) * CHAR_BIT);
+
+    friend class __bit_reference<__bitset>;
+    friend class __bit_const_reference<__bitset>;
+    friend class __bit_iterator<__bitset, false>;
+    friend class __bit_iterator<__bitset, true>;
+    friend struct __bit_array<__bitset>;
+
+    __storage_type __first_[_N_words];
+
+    typedef __bit_reference<__bitset>                  reference;
+    typedef __bit_const_reference<__bitset>            const_reference;
+    typedef __bit_iterator<__bitset, false>            iterator;
+    typedef __bit_iterator<__bitset, true>             const_iterator;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR __bitset() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    explicit _LIBCPP_CONSTEXPR __bitset(unsigned long long __v) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY reference __make_ref(size_t __pos) _NOEXCEPT
+        {return reference(__first_ + __pos / __bits_per_word, __storage_type(1) << __pos % __bits_per_word);}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR const_reference __make_ref(size_t __pos) const _NOEXCEPT
+        {return const_reference(__first_ + __pos / __bits_per_word, __storage_type(1) << __pos % __bits_per_word);}
+    _LIBCPP_INLINE_VISIBILITY iterator __make_iter(size_t __pos) _NOEXCEPT
+        {return iterator(__first_ + __pos / __bits_per_word, __pos % __bits_per_word);}
+    _LIBCPP_INLINE_VISIBILITY const_iterator __make_iter(size_t __pos) const _NOEXCEPT
+        {return const_iterator(__first_ + __pos / __bits_per_word, __pos % __bits_per_word);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator&=(const __bitset& __v) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    void operator|=(const __bitset& __v) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    void operator^=(const __bitset& __v) _NOEXCEPT;
+
+    void flip() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY unsigned long to_ulong() const
+        {return to_ulong(integral_constant<bool, _Size < sizeof(unsigned long) * CHAR_BIT>());}
+    _LIBCPP_INLINE_VISIBILITY unsigned long long to_ullong() const
+        {return to_ullong(integral_constant<bool, _Size < sizeof(unsigned long long) * CHAR_BIT>());}
+
+    bool all() const _NOEXCEPT;
+    bool any() const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    size_t __hash_code() const _NOEXCEPT;
+private:
+#ifdef _LIBCPP_CXX03_LANG
+    void __init(unsigned long long __v, false_type) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    void __init(unsigned long long __v, true_type) _NOEXCEPT;
+#endif // _LIBCPP_CXX03_LANG
+    unsigned long to_ulong(false_type) const;
+    _LIBCPP_INLINE_VISIBILITY
+    unsigned long to_ulong(true_type) const;
+    unsigned long long to_ullong(false_type) const;
+    _LIBCPP_INLINE_VISIBILITY
+    unsigned long long to_ullong(true_type) const;
+    _LIBCPP_INLINE_VISIBILITY
+    unsigned long long to_ullong(true_type, false_type) const;
+    unsigned long long to_ullong(true_type, true_type) const;
+};
+
+template <size_t _N_words, size_t _Size>
+inline
+_LIBCPP_CONSTEXPR
+__bitset<_N_words, _Size>::__bitset() _NOEXCEPT
+#ifndef _LIBCPP_CXX03_LANG
+    : __first_{0}
+#endif
+{
+#ifdef _LIBCPP_CXX03_LANG
+    _VSTD::fill_n(__first_, _N_words, __storage_type(0));
+#endif
+}
+
+#ifdef _LIBCPP_CXX03_LANG
+
+template <size_t _N_words, size_t _Size>
+void
+__bitset<_N_words, _Size>::__init(unsigned long long __v, false_type) _NOEXCEPT
+{
+    __storage_type __t[sizeof(unsigned long long) / sizeof(__storage_type)];
+    size_t __sz = _Size;
+    for (size_t __i = 0; __i < sizeof(__t)/sizeof(__t[0]); ++__i, __v >>= __bits_per_word, __sz -= __bits_per_word )
+        if ( __sz < __bits_per_word)
+            __t[__i] = static_cast<__storage_type>(__v) & ( 1ULL << __sz ) - 1;
+        else
+            __t[__i] = static_cast<__storage_type>(__v);
+
+    _VSTD::copy(__t, __t + sizeof(__t)/sizeof(__t[0]), __first_);
+    _VSTD::fill(__first_ + sizeof(__t)/sizeof(__t[0]), __first_ + sizeof(__first_)/sizeof(__first_[0]),
+               __storage_type(0));
+}
+
+template <size_t _N_words, size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+__bitset<_N_words, _Size>::__init(unsigned long long __v, true_type) _NOEXCEPT
+{
+    __first_[0] = __v;
+    if (_Size < __bits_per_word)
+        __first_[0] &= ( 1ULL << _Size ) - 1;
+
+    _VSTD::fill(__first_ + 1, __first_ + sizeof(__first_)/sizeof(__first_[0]), __storage_type(0));
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <size_t _N_words, size_t _Size>
+inline
+_LIBCPP_CONSTEXPR
+__bitset<_N_words, _Size>::__bitset(unsigned long long __v) _NOEXCEPT
+#ifndef _LIBCPP_CXX03_LANG
+#if SIZE_MAX == 0xffffffffffffffffULL
+    : __first_{__v}
+#elif SIZE_MAX == 0xffffffffULL
+    : __first_{static_cast<__storage_type>(__v),
+                _Size >= 2 * __bits_per_word ? static_cast<__storage_type>(__v >> __bits_per_word)
+                : static_cast<__storage_type>((__v >> __bits_per_word) & (__storage_type(1) << (_Size - __bits_per_word)) - 1)}
+#else
+#error This constructor has not been ported to this platform
+#endif
+#endif
+{
+#ifdef _LIBCPP_CXX03_LANG
+    __init(__v, integral_constant<bool, sizeof(unsigned long long) == sizeof(__storage_type)>());
+#endif
+}
+
+template <size_t _N_words, size_t _Size>
+inline
+void
+__bitset<_N_words, _Size>::operator&=(const __bitset& __v) _NOEXCEPT
+{
+    for (size_type __i = 0; __i < _N_words; ++__i)
+        __first_[__i] &= __v.__first_[__i];
+}
+
+template <size_t _N_words, size_t _Size>
+inline
+void
+__bitset<_N_words, _Size>::operator|=(const __bitset& __v) _NOEXCEPT
+{
+    for (size_type __i = 0; __i < _N_words; ++__i)
+        __first_[__i] |= __v.__first_[__i];
+}
+
+template <size_t _N_words, size_t _Size>
+inline
+void
+__bitset<_N_words, _Size>::operator^=(const __bitset& __v) _NOEXCEPT
+{
+    for (size_type __i = 0; __i < _N_words; ++__i)
+        __first_[__i] ^= __v.__first_[__i];
+}
+
+template <size_t _N_words, size_t _Size>
+void
+__bitset<_N_words, _Size>::flip() _NOEXCEPT
+{
+    // do middle whole words
+    size_type __n = _Size;
+    __storage_pointer __p = __first_;
+    for (; __n >= __bits_per_word; ++__p, __n -= __bits_per_word)
+        *__p = ~*__p;
+    // do last partial word
+    if (__n > 0)
+    {
+        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+        __storage_type __b = *__p & __m;
+        *__p &= ~__m;
+        *__p |= ~__b & __m;
+    }
+}
+
+template <size_t _N_words, size_t _Size>
+unsigned long
+__bitset<_N_words, _Size>::to_ulong(false_type) const
+{
+    const_iterator __e = __make_iter(_Size);
+    const_iterator __i = _VSTD::find(__make_iter(sizeof(unsigned long) * CHAR_BIT), __e, true);
+    if (__i != __e)
+        __throw_overflow_error("bitset to_ulong overflow error");
+
+    return __first_[0];
+}
+
+template <size_t _N_words, size_t _Size>
+inline
+unsigned long
+__bitset<_N_words, _Size>::to_ulong(true_type) const
+{
+    return __first_[0];
+}
+
+template <size_t _N_words, size_t _Size>
+unsigned long long
+__bitset<_N_words, _Size>::to_ullong(false_type) const
+{
+    const_iterator __e = __make_iter(_Size);
+    const_iterator __i = _VSTD::find(__make_iter(sizeof(unsigned long long) * CHAR_BIT), __e, true);
+    if (__i != __e)
+        __throw_overflow_error("bitset to_ullong overflow error");
+
+    return to_ullong(true_type());
+}
+
+template <size_t _N_words, size_t _Size>
+inline
+unsigned long long
+__bitset<_N_words, _Size>::to_ullong(true_type) const
+{
+    return to_ullong(true_type(), integral_constant<bool, sizeof(__storage_type) < sizeof(unsigned long long)>());
+}
+
+template <size_t _N_words, size_t _Size>
+inline
+unsigned long long
+__bitset<_N_words, _Size>::to_ullong(true_type, false_type) const
+{
+    return __first_[0];
+}
+
+template <size_t _N_words, size_t _Size>
+unsigned long long
+__bitset<_N_words, _Size>::to_ullong(true_type, true_type) const
+{
+    unsigned long long __r = __first_[0];
+    for (size_t __i = 1; __i < sizeof(unsigned long long) / sizeof(__storage_type); ++__i)
+        __r |= static_cast<unsigned long long>(__first_[__i]) << (sizeof(__storage_type) * CHAR_BIT);
+    return __r;
+}
+
+template <size_t _N_words, size_t _Size>
+bool
+__bitset<_N_words, _Size>::all() const _NOEXCEPT
+{
+    // do middle whole words
+    size_type __n = _Size;
+    __const_storage_pointer __p = __first_;
+    for (; __n >= __bits_per_word; ++__p, __n -= __bits_per_word)
+        if (~*__p)
+            return false;
+    // do last partial word
+    if (__n > 0)
+    {
+        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+        if (~*__p & __m)
+            return false;
+    }
+    return true;
+}
+
+template <size_t _N_words, size_t _Size>
+bool
+__bitset<_N_words, _Size>::any() const _NOEXCEPT
+{
+    // do middle whole words
+    size_type __n = _Size;
+    __const_storage_pointer __p = __first_;
+    for (; __n >= __bits_per_word; ++__p, __n -= __bits_per_word)
+        if (*__p)
+            return true;
+    // do last partial word
+    if (__n > 0)
+    {
+        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+        if (*__p & __m)
+            return true;
+    }
+    return false;
+}
+
+template <size_t _N_words, size_t _Size>
+inline
+size_t
+__bitset<_N_words, _Size>::__hash_code() const _NOEXCEPT
+{
+    size_t __h = 0;
+    for (size_type __i = 0; __i < _N_words; ++__i)
+        __h ^= __first_[__i];
+    return __h;
+}
+
+template <size_t _Size>
+class __bitset<1, _Size>
+{
+public:
+    typedef ptrdiff_t              difference_type;
+    typedef size_t                 size_type;
+    typedef size_type              __storage_type;
+protected:
+    typedef __bitset __self;
+    typedef       __storage_type*  __storage_pointer;
+    typedef const __storage_type*  __const_storage_pointer;
+    static const unsigned __bits_per_word = static_cast<unsigned>(sizeof(__storage_type) * CHAR_BIT);
+
+    friend class __bit_reference<__bitset>;
+    friend class __bit_const_reference<__bitset>;
+    friend class __bit_iterator<__bitset, false>;
+    friend class __bit_iterator<__bitset, true>;
+    friend struct __bit_array<__bitset>;
+
+    __storage_type __first_;
+
+    typedef __bit_reference<__bitset>                  reference;
+    typedef __bit_const_reference<__bitset>            const_reference;
+    typedef __bit_iterator<__bitset, false>            iterator;
+    typedef __bit_iterator<__bitset, true>             const_iterator;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR __bitset() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    explicit _LIBCPP_CONSTEXPR __bitset(unsigned long long __v) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY reference __make_ref(size_t __pos) _NOEXCEPT
+        {return reference(&__first_, __storage_type(1) << __pos);}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR const_reference __make_ref(size_t __pos) const _NOEXCEPT
+        {return const_reference(&__first_, __storage_type(1) << __pos);}
+    _LIBCPP_INLINE_VISIBILITY iterator __make_iter(size_t __pos) _NOEXCEPT
+        {return iterator(&__first_ + __pos / __bits_per_word, __pos % __bits_per_word);}
+    _LIBCPP_INLINE_VISIBILITY const_iterator __make_iter(size_t __pos) const _NOEXCEPT
+        {return const_iterator(&__first_ + __pos / __bits_per_word, __pos % __bits_per_word);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator&=(const __bitset& __v) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    void operator|=(const __bitset& __v) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    void operator^=(const __bitset& __v) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void flip() _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    unsigned long to_ulong() const;
+    _LIBCPP_INLINE_VISIBILITY
+    unsigned long long to_ullong() const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool all() const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    bool any() const _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t __hash_code() const _NOEXCEPT;
+};
+
+template <size_t _Size>
+inline
+_LIBCPP_CONSTEXPR
+__bitset<1, _Size>::__bitset() _NOEXCEPT
+    : __first_(0)
+{
+}
+
+template <size_t _Size>
+inline
+_LIBCPP_CONSTEXPR
+__bitset<1, _Size>::__bitset(unsigned long long __v) _NOEXCEPT
+    : __first_(
+        _Size == __bits_per_word ? static_cast<__storage_type>(__v)
+                                 : static_cast<__storage_type>(__v) & ((__storage_type(1) << _Size) - 1)
+    )
+{
+}
+
+template <size_t _Size>
+inline
+void
+__bitset<1, _Size>::operator&=(const __bitset& __v) _NOEXCEPT
+{
+    __first_ &= __v.__first_;
+}
+
+template <size_t _Size>
+inline
+void
+__bitset<1, _Size>::operator|=(const __bitset& __v) _NOEXCEPT
+{
+    __first_ |= __v.__first_;
+}
+
+template <size_t _Size>
+inline
+void
+__bitset<1, _Size>::operator^=(const __bitset& __v) _NOEXCEPT
+{
+    __first_ ^= __v.__first_;
+}
+
+template <size_t _Size>
+inline
+void
+__bitset<1, _Size>::flip() _NOEXCEPT
+{
+    __storage_type __m = ~__storage_type(0) >> (__bits_per_word - _Size);
+    __first_ = ~__first_;
+    __first_ &= __m;
+}
+
+template <size_t _Size>
+inline
+unsigned long
+__bitset<1, _Size>::to_ulong() const
+{
+    return __first_;
+}
+
+template <size_t _Size>
+inline
+unsigned long long
+__bitset<1, _Size>::to_ullong() const
+{
+    return __first_;
+}
+
+template <size_t _Size>
+inline
+bool
+__bitset<1, _Size>::all() const _NOEXCEPT
+{
+    __storage_type __m = ~__storage_type(0) >> (__bits_per_word - _Size);
+    return !(~__first_ & __m);
+}
+
+template <size_t _Size>
+inline
+bool
+__bitset<1, _Size>::any() const _NOEXCEPT
+{
+    __storage_type __m = ~__storage_type(0) >> (__bits_per_word - _Size);
+    return __first_ & __m;
+}
+
+template <size_t _Size>
+inline
+size_t
+__bitset<1, _Size>::__hash_code() const _NOEXCEPT
+{
+    return __first_;
+}
+
+template <>
+class __bitset<0, 0>
+{
+public:
+    typedef ptrdiff_t              difference_type;
+    typedef size_t                 size_type;
+    typedef size_type              __storage_type;
+protected:
+    typedef __bitset __self;
+    typedef       __storage_type*  __storage_pointer;
+    typedef const __storage_type*  __const_storage_pointer;
+    static const unsigned __bits_per_word = static_cast<unsigned>(sizeof(__storage_type) * CHAR_BIT);
+
+    friend class __bit_reference<__bitset>;
+    friend class __bit_const_reference<__bitset>;
+    friend class __bit_iterator<__bitset, false>;
+    friend class __bit_iterator<__bitset, true>;
+    friend struct __bit_array<__bitset>;
+
+    typedef __bit_reference<__bitset>                  reference;
+    typedef __bit_const_reference<__bitset>            const_reference;
+    typedef __bit_iterator<__bitset, false>            iterator;
+    typedef __bit_iterator<__bitset, true>             const_iterator;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR __bitset() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    explicit _LIBCPP_CONSTEXPR __bitset(unsigned long long) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY reference __make_ref(size_t) _NOEXCEPT
+        {return reference(nullptr, 1);}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR const_reference __make_ref(size_t) const _NOEXCEPT
+        {return const_reference(nullptr, 1);}
+    _LIBCPP_INLINE_VISIBILITY iterator __make_iter(size_t) _NOEXCEPT
+        {return iterator(nullptr, 0);}
+    _LIBCPP_INLINE_VISIBILITY const_iterator __make_iter(size_t) const _NOEXCEPT
+        {return const_iterator(nullptr, 0);}
+
+    _LIBCPP_INLINE_VISIBILITY void operator&=(const __bitset&) _NOEXCEPT {}
+    _LIBCPP_INLINE_VISIBILITY void operator|=(const __bitset&) _NOEXCEPT {}
+    _LIBCPP_INLINE_VISIBILITY void operator^=(const __bitset&) _NOEXCEPT {}
+
+    _LIBCPP_INLINE_VISIBILITY void flip() _NOEXCEPT {}
+
+    _LIBCPP_INLINE_VISIBILITY unsigned long to_ulong() const {return 0;}
+    _LIBCPP_INLINE_VISIBILITY unsigned long long to_ullong() const {return 0;}
+
+    _LIBCPP_INLINE_VISIBILITY bool all() const _NOEXCEPT {return true;}
+    _LIBCPP_INLINE_VISIBILITY bool any() const _NOEXCEPT {return false;}
+
+    _LIBCPP_INLINE_VISIBILITY size_t __hash_code() const _NOEXCEPT {return 0;}
+};
+
+inline
+_LIBCPP_CONSTEXPR
+__bitset<0, 0>::__bitset() _NOEXCEPT
+{
+}
+
+inline
+_LIBCPP_CONSTEXPR
+__bitset<0, 0>::__bitset(unsigned long long) _NOEXCEPT
+{
+}
+
+template <size_t _Size> class _LIBCPP_TEMPLATE_VIS bitset;
+template <size_t _Size> struct hash<bitset<_Size> >;
+
+template <size_t _Size>
+class _LIBCPP_TEMPLATE_VIS bitset
+    : private __bitset<_Size == 0 ? 0 : (_Size - 1) / (sizeof(size_t) * CHAR_BIT) + 1, _Size>
+{
+public:
+    static const unsigned __n_words = _Size == 0 ? 0 : (_Size - 1) / (sizeof(size_t) * CHAR_BIT) + 1;
+    typedef __bitset<__n_words, _Size> base;
+
+public:
+    typedef typename base::reference       reference;
+    typedef typename base::const_reference const_reference;
+
+    // 23.3.5.1 constructors:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR bitset() _NOEXCEPT {}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+        bitset(unsigned long long __v) _NOEXCEPT : base(__v) {}
+    template<class _CharT, class = __enable_if_t<_IsCharLikeType<_CharT>::value> >
+        explicit bitset(const _CharT* __str,
+                        typename basic_string<_CharT>::size_type __n = basic_string<_CharT>::npos,
+                        _CharT __zero = _CharT('0'), _CharT __one = _CharT('1'));
+    template<class _CharT, class _Traits, class _Allocator>
+        explicit bitset(const basic_string<_CharT,_Traits,_Allocator>& __str,
+                        typename basic_string<_CharT,_Traits,_Allocator>::size_type __pos = 0,
+                        typename basic_string<_CharT,_Traits,_Allocator>::size_type __n =
+                                (basic_string<_CharT,_Traits,_Allocator>::npos),
+                        _CharT __zero = _CharT('0'), _CharT __one = _CharT('1'));
+
+    // 23.3.5.2 bitset operations:
+    _LIBCPP_INLINE_VISIBILITY
+    bitset& operator&=(const bitset& __rhs) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    bitset& operator|=(const bitset& __rhs) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    bitset& operator^=(const bitset& __rhs) _NOEXCEPT;
+    bitset& operator<<=(size_t __pos) _NOEXCEPT;
+    bitset& operator>>=(size_t __pos) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    bitset& set() _NOEXCEPT;
+    bitset& set(size_t __pos, bool __val = true);
+    _LIBCPP_INLINE_VISIBILITY
+    bitset& reset() _NOEXCEPT;
+    bitset& reset(size_t __pos);
+    _LIBCPP_INLINE_VISIBILITY
+    bitset  operator~() const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    bitset& flip() _NOEXCEPT;
+    bitset& flip(size_t __pos);
+
+    // element access:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+                              const_reference operator[](size_t __p) const {return base::__make_ref(__p);}
+    _LIBCPP_INLINE_VISIBILITY       reference operator[](size_t __p)       {return base::__make_ref(__p);}
+    _LIBCPP_INLINE_VISIBILITY
+    unsigned long to_ulong() const;
+    _LIBCPP_INLINE_VISIBILITY
+    unsigned long long to_ullong() const;
+    template <class _CharT, class _Traits, class _Allocator>
+        basic_string<_CharT, _Traits, _Allocator> to_string(_CharT __zero = _CharT('0'),
+                                                            _CharT __one = _CharT('1')) const;
+    template <class _CharT, class _Traits>
+        _LIBCPP_INLINE_VISIBILITY
+        basic_string<_CharT, _Traits, allocator<_CharT> > to_string(_CharT __zero = _CharT('0'),
+                                                                    _CharT __one = _CharT('1')) const;
+    template <class _CharT>
+        _LIBCPP_INLINE_VISIBILITY
+        basic_string<_CharT, char_traits<_CharT>, allocator<_CharT> > to_string(_CharT __zero = _CharT('0'),
+                                                                                _CharT __one = _CharT('1')) const;
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string<char, char_traits<char>, allocator<char> > to_string(char __zero = '0',
+                                                                      char __one = '1') const;
+    _LIBCPP_INLINE_VISIBILITY
+    size_t count() const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR size_t size() const _NOEXCEPT {return _Size;}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const bitset& __rhs) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const bitset& __rhs) const _NOEXCEPT;
+    bool test(size_t __pos) const;
+    _LIBCPP_INLINE_VISIBILITY
+    bool all() const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    bool any() const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY bool none() const _NOEXCEPT {return !any();}
+    _LIBCPP_INLINE_VISIBILITY
+    bitset operator<<(size_t __pos) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    bitset operator>>(size_t __pos) const _NOEXCEPT;
+
+private:
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t __hash_code() const _NOEXCEPT {return base::__hash_code();}
+
+    friend struct hash<bitset>;
+};
+
+template <size_t _Size>
+template<class _CharT, class>
+bitset<_Size>::bitset(const _CharT* __str,
+                      typename basic_string<_CharT>::size_type __n,
+                      _CharT __zero, _CharT __one)
+{
+    size_t __rlen = _VSTD::min(__n, char_traits<_CharT>::length(__str));
+    for (size_t __i = 0; __i < __rlen; ++__i)
+        if (__str[__i] != __zero && __str[__i] != __one)
+            __throw_invalid_argument("bitset string ctor has invalid argument");
+
+    size_t _Mp = _VSTD::min(__rlen, _Size);
+    size_t __i = 0;
+    for (; __i < _Mp; ++__i)
+    {
+        _CharT __c = __str[_Mp - 1 - __i];
+        (*this)[__i] = (__c == __one);
+    }
+    _VSTD::fill(base::__make_iter(__i), base::__make_iter(_Size), false);
+}
+
+template <size_t _Size>
+template<class _CharT, class _Traits, class _Allocator>
+bitset<_Size>::bitset(const basic_string<_CharT,_Traits,_Allocator>& __str,
+       typename basic_string<_CharT,_Traits,_Allocator>::size_type __pos,
+       typename basic_string<_CharT,_Traits,_Allocator>::size_type __n,
+       _CharT __zero, _CharT __one)
+{
+    if (__pos > __str.size())
+        __throw_out_of_range("bitset string pos out of range");
+
+    size_t __rlen = _VSTD::min(__n, __str.size() - __pos);
+    for (size_t __i = __pos; __i < __pos + __rlen; ++__i)
+        if (!_Traits::eq(__str[__i], __zero) && !_Traits::eq(__str[__i], __one))
+            __throw_invalid_argument("bitset string ctor has invalid argument");
+
+    size_t _Mp = _VSTD::min(__rlen, _Size);
+    size_t __i = 0;
+    for (; __i < _Mp; ++__i)
+    {
+        _CharT __c = __str[__pos + _Mp - 1 - __i];
+        (*this)[__i] = _Traits::eq(__c, __one);
+    }
+    _VSTD::fill(base::__make_iter(__i), base::__make_iter(_Size), false);
+}
+
+template <size_t _Size>
+inline
+bitset<_Size>&
+bitset<_Size>::operator&=(const bitset& __rhs) _NOEXCEPT
+{
+    base::operator&=(__rhs);
+    return *this;
+}
+
+template <size_t _Size>
+inline
+bitset<_Size>&
+bitset<_Size>::operator|=(const bitset& __rhs) _NOEXCEPT
+{
+    base::operator|=(__rhs);
+    return *this;
+}
+
+template <size_t _Size>
+inline
+bitset<_Size>&
+bitset<_Size>::operator^=(const bitset& __rhs) _NOEXCEPT
+{
+    base::operator^=(__rhs);
+    return *this;
+}
+
+template <size_t _Size>
+bitset<_Size>&
+bitset<_Size>::operator<<=(size_t __pos) _NOEXCEPT
+{
+    __pos = _VSTD::min(__pos, _Size);
+    _VSTD::copy_backward(base::__make_iter(0), base::__make_iter(_Size - __pos), base::__make_iter(_Size));
+    _VSTD::fill_n(base::__make_iter(0), __pos, false);
+    return *this;
+}
+
+template <size_t _Size>
+bitset<_Size>&
+bitset<_Size>::operator>>=(size_t __pos) _NOEXCEPT
+{
+    __pos = _VSTD::min(__pos, _Size);
+    _VSTD::copy(base::__make_iter(__pos), base::__make_iter(_Size), base::__make_iter(0));
+    _VSTD::fill_n(base::__make_iter(_Size - __pos), __pos, false);
+    return *this;
+}
+
+template <size_t _Size>
+inline
+bitset<_Size>&
+bitset<_Size>::set() _NOEXCEPT
+{
+    _VSTD::fill_n(base::__make_iter(0), _Size, true);
+    return *this;
+}
+
+template <size_t _Size>
+bitset<_Size>&
+bitset<_Size>::set(size_t __pos, bool __val)
+{
+    if (__pos >= _Size)
+        __throw_out_of_range("bitset set argument out of range");
+
+    (*this)[__pos] = __val;
+    return *this;
+}
+
+template <size_t _Size>
+inline
+bitset<_Size>&
+bitset<_Size>::reset() _NOEXCEPT
+{
+    _VSTD::fill_n(base::__make_iter(0), _Size, false);
+    return *this;
+}
+
+template <size_t _Size>
+bitset<_Size>&
+bitset<_Size>::reset(size_t __pos)
+{
+    if (__pos >= _Size)
+        __throw_out_of_range("bitset reset argument out of range");
+
+    (*this)[__pos] = false;
+    return *this;
+}
+
+template <size_t _Size>
+inline
+bitset<_Size>
+bitset<_Size>::operator~() const _NOEXCEPT
+{
+    bitset __x(*this);
+    __x.flip();
+    return __x;
+}
+
+template <size_t _Size>
+inline
+bitset<_Size>&
+bitset<_Size>::flip() _NOEXCEPT
+{
+    base::flip();
+    return *this;
+}
+
+template <size_t _Size>
+bitset<_Size>&
+bitset<_Size>::flip(size_t __pos)
+{
+    if (__pos >= _Size)
+        __throw_out_of_range("bitset flip argument out of range");
+
+    reference r = base::__make_ref(__pos);
+    r = ~r;
+    return *this;
+}
+
+template <size_t _Size>
+inline
+unsigned long
+bitset<_Size>::to_ulong() const
+{
+    return base::to_ulong();
+}
+
+template <size_t _Size>
+inline
+unsigned long long
+bitset<_Size>::to_ullong() const
+{
+    return base::to_ullong();
+}
+
+template <size_t _Size>
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>
+bitset<_Size>::to_string(_CharT __zero, _CharT __one) const
+{
+    basic_string<_CharT, _Traits, _Allocator> __r(_Size, __zero);
+    for (size_t __i = 0; __i < _Size; ++__i)
+    {
+        if ((*this)[__i])
+            __r[_Size - 1 - __i] = __one;
+    }
+    return __r;
+}
+
+template <size_t _Size>
+template <class _CharT, class _Traits>
+inline
+basic_string<_CharT, _Traits, allocator<_CharT> >
+bitset<_Size>::to_string(_CharT __zero, _CharT __one) const
+{
+    return to_string<_CharT, _Traits, allocator<_CharT> >(__zero, __one);
+}
+
+template <size_t _Size>
+template <class _CharT>
+inline
+basic_string<_CharT, char_traits<_CharT>, allocator<_CharT> >
+bitset<_Size>::to_string(_CharT __zero, _CharT __one) const
+{
+    return to_string<_CharT, char_traits<_CharT>, allocator<_CharT> >(__zero, __one);
+}
+
+template <size_t _Size>
+inline
+basic_string<char, char_traits<char>, allocator<char> >
+bitset<_Size>::to_string(char __zero, char __one) const
+{
+    return to_string<char, char_traits<char>, allocator<char> >(__zero, __one);
+}
+
+template <size_t _Size>
+inline
+size_t
+bitset<_Size>::count() const _NOEXCEPT
+{
+    return static_cast<size_t>(_VSTD::__count_bool_true(base::__make_iter(0), _Size));
+}
+
+template <size_t _Size>
+inline
+bool
+bitset<_Size>::operator==(const bitset& __rhs) const _NOEXCEPT
+{
+    return _VSTD::equal(base::__make_iter(0), base::__make_iter(_Size), __rhs.__make_iter(0));
+}
+
+template <size_t _Size>
+inline
+bool
+bitset<_Size>::operator!=(const bitset& __rhs) const _NOEXCEPT
+{
+    return !(*this == __rhs);
+}
+
+template <size_t _Size>
+bool
+bitset<_Size>::test(size_t __pos) const
+{
+    if (__pos >= _Size)
+        __throw_out_of_range("bitset test argument out of range");
+
+    return (*this)[__pos];
+}
+
+template <size_t _Size>
+inline
+bool
+bitset<_Size>::all() const _NOEXCEPT
+{
+    return base::all();
+}
+
+template <size_t _Size>
+inline
+bool
+bitset<_Size>::any() const _NOEXCEPT
+{
+    return base::any();
+}
+
+template <size_t _Size>
+inline
+bitset<_Size>
+bitset<_Size>::operator<<(size_t __pos) const _NOEXCEPT
+{
+    bitset __r = *this;
+    __r <<= __pos;
+    return __r;
+}
+
+template <size_t _Size>
+inline
+bitset<_Size>
+bitset<_Size>::operator>>(size_t __pos) const _NOEXCEPT
+{
+    bitset __r = *this;
+    __r >>= __pos;
+    return __r;
+}
+
+template <size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+bitset<_Size>
+operator&(const bitset<_Size>& __x, const bitset<_Size>& __y) _NOEXCEPT
+{
+    bitset<_Size> __r = __x;
+    __r &= __y;
+    return __r;
+}
+
+template <size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+bitset<_Size>
+operator|(const bitset<_Size>& __x, const bitset<_Size>& __y) _NOEXCEPT
+{
+    bitset<_Size> __r = __x;
+    __r |= __y;
+    return __r;
+}
+
+template <size_t _Size>
+inline _LIBCPP_INLINE_VISIBILITY
+bitset<_Size>
+operator^(const bitset<_Size>& __x, const bitset<_Size>& __y) _NOEXCEPT
+{
+    bitset<_Size> __r = __x;
+    __r ^= __y;
+    return __r;
+}
+
+template <size_t _Size>
+struct _LIBCPP_TEMPLATE_VIS hash<bitset<_Size> >
+    : public unary_function<bitset<_Size>, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const bitset<_Size>& __bs) const _NOEXCEPT
+        {return __bs.__hash_code();}
+};
+
+template <class _CharT, class _Traits, size_t _Size>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, bitset<_Size>& __x);
+
+template <class _CharT, class _Traits, size_t _Size>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const bitset<_Size>& __x);
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_BITSET
diff --git a/contrib/libs/cxxsupp/libcxx/include/cassert b/contrib/libs/cxxsupp/libcxx/include/cassert
new file mode 100644
index 00000000000..25a0a746b8d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cassert
@@ -0,0 +1,24 @@
+// -*- C++ -*-
+//===-------------------------- cassert -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+/*
+    cassert synopsis
+
+Macros:
+
+    assert
+
+*/
+
+#include <__config>
+#include <assert.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/include/ccomplex b/contrib/libs/cxxsupp/libcxx/include/ccomplex
new file mode 100644
index 00000000000..cea45091284
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/ccomplex
@@ -0,0 +1,28 @@
+// -*- C++ -*-
+//===--------------------------- ccomplex ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CCOMPLEX
+#define _LIBCPP_CCOMPLEX
+
+/*
+    ccomplex synopsis
+
+#include <complex>
+
+*/
+
+#include <complex>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+// hh 080623 Created
+
+#endif // _LIBCPP_CCOMPLEX
diff --git a/contrib/libs/cxxsupp/libcxx/include/cctype b/contrib/libs/cxxsupp/libcxx/include/cctype
new file mode 100644
index 00000000000..b078056862a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cctype
@@ -0,0 +1,120 @@
+// -*- C++ -*-
+//===---------------------------- cctype ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CCTYPE
+#define _LIBCPP_CCTYPE
+
+/*
+    cctype synopsis
+
+namespace std
+{
+
+int isalnum(int c);
+int isalpha(int c);
+int isblank(int c);  // C99
+int iscntrl(int c);
+int isdigit(int c);
+int isgraph(int c);
+int islower(int c);
+int isprint(int c);
+int ispunct(int c);
+int isspace(int c);
+int isupper(int c);
+int isxdigit(int c);
+int tolower(int c);
+int toupper(int c);
+
+}  // std
+*/
+
+#include <__config>
+#include <ctype.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifdef isalnum
+#undef isalnum
+#endif
+
+#ifdef isalpha
+#undef isalpha
+#endif
+
+#ifdef isblank
+#undef isblank
+#endif
+
+#ifdef iscntrl
+#undef iscntrl
+#endif
+
+#ifdef isdigit
+#undef isdigit
+#endif
+
+#ifdef isgraph
+#undef isgraph
+#endif
+
+#ifdef islower
+#undef islower
+#endif
+
+#ifdef isprint
+#undef isprint
+#endif
+
+#ifdef ispunct
+#undef ispunct
+#endif
+
+#ifdef isspace
+#undef isspace
+#endif
+
+#ifdef isupper
+#undef isupper
+#endif
+
+#ifdef isxdigit
+#undef isxdigit
+#endif
+
+#ifdef tolower
+#undef tolower
+#endif
+
+#ifdef toupper
+#undef toupper
+#endif
+
+
+using ::isalnum _LIBCPP_USING_IF_EXISTS;
+using ::isalpha _LIBCPP_USING_IF_EXISTS;
+using ::isblank _LIBCPP_USING_IF_EXISTS;
+using ::iscntrl _LIBCPP_USING_IF_EXISTS;
+using ::isdigit _LIBCPP_USING_IF_EXISTS;
+using ::isgraph _LIBCPP_USING_IF_EXISTS;
+using ::islower _LIBCPP_USING_IF_EXISTS;
+using ::isprint _LIBCPP_USING_IF_EXISTS;
+using ::ispunct _LIBCPP_USING_IF_EXISTS;
+using ::isspace _LIBCPP_USING_IF_EXISTS;
+using ::isupper _LIBCPP_USING_IF_EXISTS;
+using ::isxdigit _LIBCPP_USING_IF_EXISTS;
+using ::tolower _LIBCPP_USING_IF_EXISTS;
+using ::toupper _LIBCPP_USING_IF_EXISTS;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CCTYPE
diff --git a/contrib/libs/cxxsupp/libcxx/include/cerrno b/contrib/libs/cxxsupp/libcxx/include/cerrno
new file mode 100644
index 00000000000..1388d7eac22
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cerrno
@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===-------------------------- cerrno ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CERRNO
+#define _LIBCPP_CERRNO
+
+/*
+    cerrno synopsis
+
+Macros:
+
+    EDOM
+    EILSEQ  // C99
+    ERANGE
+    errno
+
+*/
+
+#include <__config>
+#include <errno.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#endif // _LIBCPP_CERRNO
diff --git a/contrib/libs/cxxsupp/libcxx/include/cfenv b/contrib/libs/cxxsupp/libcxx/include/cfenv
new file mode 100644
index 00000000000..05b55ee364f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cfenv
@@ -0,0 +1,81 @@
+// -*- C++ -*-
+//===---------------------------- cfenv -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CFENV
+#define _LIBCPP_CFENV
+
+/*
+    cfenv synopsis
+
+This entire header is C99 / C++0X
+
+Macros:
+
+    FE_DIVBYZERO
+    FE_INEXACT
+    FE_INVALID
+    FE_OVERFLOW
+    FE_UNDERFLOW
+    FE_ALL_EXCEPT
+    FE_DOWNWARD
+    FE_TONEAREST
+    FE_TOWARDZERO
+    FE_UPWARD
+    FE_DFL_ENV
+
+namespace std
+{
+
+Types:
+
+    fenv_t
+    fexcept_t
+
+int feclearexcept(int excepts);
+int fegetexceptflag(fexcept_t* flagp, int excepts);
+int feraiseexcept(int excepts);
+int fesetexceptflag(const fexcept_t* flagp, int excepts);
+int fetestexcept(int excepts);
+int fegetround();
+int fesetround(int round);
+int fegetenv(fenv_t* envp);
+int feholdexcept(fenv_t* envp);
+int fesetenv(const fenv_t* envp);
+int feupdateenv(const fenv_t* envp);
+
+}  // std
+*/
+
+#include <__config>
+#include <fenv.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::fenv_t _LIBCPP_USING_IF_EXISTS;
+using ::fexcept_t _LIBCPP_USING_IF_EXISTS;
+
+using ::feclearexcept _LIBCPP_USING_IF_EXISTS;
+using ::fegetexceptflag _LIBCPP_USING_IF_EXISTS;
+using ::feraiseexcept _LIBCPP_USING_IF_EXISTS;
+using ::fesetexceptflag _LIBCPP_USING_IF_EXISTS;
+using ::fetestexcept _LIBCPP_USING_IF_EXISTS;
+using ::fegetround _LIBCPP_USING_IF_EXISTS;
+using ::fesetround _LIBCPP_USING_IF_EXISTS;
+using ::fegetenv _LIBCPP_USING_IF_EXISTS;
+using ::feholdexcept _LIBCPP_USING_IF_EXISTS;
+using ::fesetenv _LIBCPP_USING_IF_EXISTS;
+using ::feupdateenv _LIBCPP_USING_IF_EXISTS;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CFENV
diff --git a/contrib/libs/cxxsupp/libcxx/include/cfloat b/contrib/libs/cxxsupp/libcxx/include/cfloat
new file mode 100644
index 00000000000..77ff5261e3a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cfloat
@@ -0,0 +1,79 @@
+// -*- C++ -*-
+//===--------------------------- cfloat -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CFLOAT
+#define _LIBCPP_CFLOAT
+
+/*
+    cfloat synopsis
+
+Macros:
+
+    FLT_ROUNDS
+    FLT_EVAL_METHOD     // C99
+    FLT_RADIX
+
+    FLT_HAS_SUBNORM     // C11
+    DBL_HAS_SUBNORM     // C11
+    LDBL_HAS_SUBNORM    // C11
+
+    FLT_MANT_DIG
+    DBL_MANT_DIG
+    LDBL_MANT_DIG
+
+    DECIMAL_DIG         // C99
+    FLT_DECIMAL_DIG     // C11
+    DBL_DECIMAL_DIG     // C11
+    LDBL_DECIMAL_DIG    // C11
+
+    FLT_DIG
+    DBL_DIG
+    LDBL_DIG
+
+    FLT_MIN_EXP
+    DBL_MIN_EXP
+    LDBL_MIN_EXP
+
+    FLT_MIN_10_EXP
+    DBL_MIN_10_EXP
+    LDBL_MIN_10_EXP
+
+    FLT_MAX_EXP
+    DBL_MAX_EXP
+    LDBL_MAX_EXP
+
+    FLT_MAX_10_EXP
+    DBL_MAX_10_EXP
+    LDBL_MAX_10_EXP
+
+    FLT_MAX
+    DBL_MAX
+    LDBL_MAX
+
+    FLT_EPSILON
+    DBL_EPSILON
+    LDBL_EPSILON
+
+    FLT_MIN
+    DBL_MIN
+    LDBL_MIN
+
+    FLT_TRUE_MIN        // C11
+    DBL_TRUE_MIN        // C11
+    LDBL_TRUE_MIN       // C11
+*/
+
+#include <__config>
+#include <float.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#endif // _LIBCPP_CFLOAT
diff --git a/contrib/libs/cxxsupp/libcxx/include/charconv b/contrib/libs/cxxsupp/libcxx/include/charconv
new file mode 100644
index 00000000000..2fdab7f007c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/charconv
@@ -0,0 +1,603 @@
+// -*- C++ -*-
+//===------------------------------ charconv ------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CHARCONV
+#define _LIBCPP_CHARCONV
+
+/*
+    charconv synopsis
+
+namespace std {
+
+  // floating-point format for primitive numerical conversion
+  enum class chars_format {
+    scientific = unspecified,
+    fixed = unspecified,
+    hex = unspecified,
+    general = fixed | scientific
+  };
+
+  // 23.20.2, primitive numerical output conversion
+  struct to_chars_result {
+    char* ptr;
+    errc ec;
+  };
+
+  to_chars_result to_chars(char* first, char* last, see below value,
+                           int base = 10);
+
+  to_chars_result to_chars(char* first, char* last, float value);
+  to_chars_result to_chars(char* first, char* last, double value);
+  to_chars_result to_chars(char* first, char* last, long double value);
+
+  to_chars_result to_chars(char* first, char* last, float value,
+                           chars_format fmt);
+  to_chars_result to_chars(char* first, char* last, double value,
+                           chars_format fmt);
+  to_chars_result to_chars(char* first, char* last, long double value,
+                           chars_format fmt);
+
+  to_chars_result to_chars(char* first, char* last, float value,
+                           chars_format fmt, int precision);
+  to_chars_result to_chars(char* first, char* last, double value,
+                           chars_format fmt, int precision);
+  to_chars_result to_chars(char* first, char* last, long double value,
+                           chars_format fmt, int precision);
+
+  // 23.20.3, primitive numerical input conversion
+  struct from_chars_result {
+    const char* ptr;
+    errc ec;
+  };
+
+  from_chars_result from_chars(const char* first, const char* last,
+                               see below& value, int base = 10);
+
+  from_chars_result from_chars(const char* first, const char* last,
+                               float& value,
+                               chars_format fmt = chars_format::general);
+  from_chars_result from_chars(const char* first, const char* last,
+                               double& value,
+                               chars_format fmt = chars_format::general);
+  from_chars_result from_chars(const char* first, const char* last,
+                               long double& value,
+                               chars_format fmt = chars_format::general);
+
+} // namespace std
+
+*/
+
+#include <__availability>
+#include <__bits>
+#include <__charconv/chars_format.h>
+#include <__charconv/from_chars_result.h>
+#include <__charconv/to_chars_result.h>
+#include <__config>
+#include <__errc>
+#include <cmath> // for log2f
+#include <cstdint>
+#include <cstdlib> // for _LIBCPP_UNREACHABLE
+#include <cstring>
+#include <limits>
+#include <type_traits>
+
+#include <__debug>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace __itoa {
+_LIBCPP_AVAILABILITY_TO_CHARS _LIBCPP_FUNC_VIS char* __u64toa(uint64_t __value, char* __buffer) _NOEXCEPT;
+_LIBCPP_AVAILABILITY_TO_CHARS _LIBCPP_FUNC_VIS char* __u32toa(uint32_t __value, char* __buffer) _NOEXCEPT;
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+void to_chars(char*, char*, bool, int = 10) = delete;
+void from_chars(const char*, const char*, bool, int = 10) = delete;
+
+namespace __itoa
+{
+
+static _LIBCPP_CONSTEXPR uint64_t __pow10_64[] = {
+    UINT64_C(0),
+    UINT64_C(10),
+    UINT64_C(100),
+    UINT64_C(1000),
+    UINT64_C(10000),
+    UINT64_C(100000),
+    UINT64_C(1000000),
+    UINT64_C(10000000),
+    UINT64_C(100000000),
+    UINT64_C(1000000000),
+    UINT64_C(10000000000),
+    UINT64_C(100000000000),
+    UINT64_C(1000000000000),
+    UINT64_C(10000000000000),
+    UINT64_C(100000000000000),
+    UINT64_C(1000000000000000),
+    UINT64_C(10000000000000000),
+    UINT64_C(100000000000000000),
+    UINT64_C(1000000000000000000),
+    UINT64_C(10000000000000000000),
+};
+
+static _LIBCPP_CONSTEXPR uint32_t __pow10_32[] = {
+    UINT32_C(0),          UINT32_C(10),       UINT32_C(100),
+    UINT32_C(1000),       UINT32_C(10000),    UINT32_C(100000),
+    UINT32_C(1000000),    UINT32_C(10000000), UINT32_C(100000000),
+    UINT32_C(1000000000),
+};
+
+template <typename _Tp, typename = void>
+struct _LIBCPP_HIDDEN __traits_base
+{
+    using type = uint64_t;
+
+    static _LIBCPP_INLINE_VISIBILITY int __width(_Tp __v)
+    {
+        auto __t = (64 - _VSTD::__libcpp_clz(static_cast<type>(__v | 1))) * 1233 >> 12;
+        return __t - (__v < __pow10_64[__t]) + 1;
+    }
+
+    _LIBCPP_AVAILABILITY_TO_CHARS
+    static _LIBCPP_INLINE_VISIBILITY char* __convert(_Tp __v, char* __p)
+    {
+        return __u64toa(__v, __p);
+    }
+
+    static _LIBCPP_INLINE_VISIBILITY decltype(__pow10_64)& __pow() { return __pow10_64; }
+};
+
+template <typename _Tp>
+struct _LIBCPP_HIDDEN
+    __traits_base<_Tp, decltype(void(uint32_t{declval<_Tp>()}))>
+{
+    using type = uint32_t;
+
+    static _LIBCPP_INLINE_VISIBILITY int __width(_Tp __v)
+    {
+        auto __t = (32 - _VSTD::__libcpp_clz(static_cast<type>(__v | 1))) * 1233 >> 12;
+        return __t - (__v < __pow10_32[__t]) + 1;
+    }
+
+    _LIBCPP_AVAILABILITY_TO_CHARS
+    static _LIBCPP_INLINE_VISIBILITY char* __convert(_Tp __v, char* __p)
+    {
+        return __u32toa(__v, __p);
+    }
+
+    static _LIBCPP_INLINE_VISIBILITY decltype(__pow10_32)& __pow() { return __pow10_32; }
+};
+
+template <typename _Tp>
+inline _LIBCPP_INLINE_VISIBILITY bool
+__mul_overflowed(unsigned char __a, _Tp __b, unsigned char& __r)
+{
+    auto __c = __a * __b;
+    __r = __c;
+    return __c > numeric_limits<unsigned char>::max();
+}
+
+template <typename _Tp>
+inline _LIBCPP_INLINE_VISIBILITY bool
+__mul_overflowed(unsigned short __a, _Tp __b, unsigned short& __r)
+{
+    auto __c = __a * __b;
+    __r = __c;
+    return __c > numeric_limits<unsigned short>::max();
+}
+
+template <typename _Tp>
+inline _LIBCPP_INLINE_VISIBILITY bool
+__mul_overflowed(_Tp __a, _Tp __b, _Tp& __r)
+{
+    static_assert(is_unsigned<_Tp>::value, "");
+#if !defined(_LIBCPP_COMPILER_MSVC)
+    return __builtin_mul_overflow(__a, __b, &__r);
+#else
+    bool __did = __b && (numeric_limits<_Tp>::max() / __b) < __a;
+    __r = __a * __b;
+    return __did;
+#endif
+}
+
+template <typename _Tp, typename _Up>
+inline _LIBCPP_INLINE_VISIBILITY bool
+__mul_overflowed(_Tp __a, _Up __b, _Tp& __r)
+{
+    return __mul_overflowed(__a, static_cast<_Tp>(__b), __r);
+}
+
+template <typename _Tp>
+struct _LIBCPP_HIDDEN __traits : __traits_base<_Tp>
+{
+    static _LIBCPP_CONSTEXPR int digits = numeric_limits<_Tp>::digits10 + 1;
+    using __traits_base<_Tp>::__pow;
+    using typename __traits_base<_Tp>::type;
+
+    // precondition: at least one non-zero character available
+    static _LIBCPP_INLINE_VISIBILITY char const*
+    __read(char const* __p, char const* __ep, type& __a, type& __b)
+    {
+        type __cprod[digits];
+        int __j = digits - 1;
+        int __i = digits;
+        do
+        {
+            if (!('0' <= *__p && *__p <= '9'))
+                break;
+            __cprod[--__i] = *__p++ - '0';
+        } while (__p != __ep && __i != 0);
+
+        __a = __inner_product(__cprod + __i + 1, __cprod + __j, __pow() + 1,
+                              __cprod[__i]);
+        if (__mul_overflowed(__cprod[__j], __pow()[__j - __i], __b))
+            --__p;
+        return __p;
+    }
+
+    template <typename _It1, typename _It2, class _Up>
+    static _LIBCPP_INLINE_VISIBILITY _Up
+    __inner_product(_It1 __first1, _It1 __last1, _It2 __first2, _Up __init)
+    {
+        for (; __first1 < __last1; ++__first1, ++__first2)
+            __init = __init + *__first1 * *__first2;
+        return __init;
+    }
+};
+
+}  // namespace __itoa
+
+template <typename _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _Tp
+__complement(_Tp __x)
+{
+    static_assert(is_unsigned<_Tp>::value, "cast to unsigned first");
+    return _Tp(~__x + 1);
+}
+
+template <typename _Tp>
+_LIBCPP_AVAILABILITY_TO_CHARS
+inline _LIBCPP_INLINE_VISIBILITY to_chars_result
+__to_chars_itoa(char* __first, char* __last, _Tp __value, true_type)
+{
+    auto __x = __to_unsigned_like(__value);
+    if (__value < 0 && __first != __last)
+    {
+        *__first++ = '-';
+        __x = __complement(__x);
+    }
+
+    return __to_chars_itoa(__first, __last, __x, false_type());
+}
+
+template <typename _Tp>
+_LIBCPP_AVAILABILITY_TO_CHARS
+inline _LIBCPP_INLINE_VISIBILITY to_chars_result
+__to_chars_itoa(char* __first, char* __last, _Tp __value, false_type)
+{
+    using __tx = __itoa::__traits<_Tp>;
+    auto __diff = __last - __first;
+
+    if (__tx::digits <= __diff || __tx::__width(__value) <= __diff)
+        return {__tx::__convert(__value, __first), errc(0)};
+    else
+        return {__last, errc::value_too_large};
+}
+
+template <typename _Tp>
+_LIBCPP_AVAILABILITY_TO_CHARS
+inline _LIBCPP_INLINE_VISIBILITY to_chars_result
+__to_chars_integral(char* __first, char* __last, _Tp __value, int __base,
+                    true_type)
+{
+    auto __x = __to_unsigned_like(__value);
+    if (__value < 0 && __first != __last)
+    {
+        *__first++ = '-';
+        __x = __complement(__x);
+    }
+
+    return __to_chars_integral(__first, __last, __x, __base, false_type());
+}
+
+template <typename _Tp>
+_LIBCPP_AVAILABILITY_TO_CHARS _LIBCPP_INLINE_VISIBILITY int __to_chars_integral_width(_Tp __value, unsigned __base) {
+  _LIBCPP_ASSERT(__value >= 0, "The function requires a non-negative value.");
+
+  unsigned __base_2 = __base * __base;
+  unsigned __base_3 = __base_2 * __base;
+  unsigned __base_4 = __base_2 * __base_2;
+
+  int __r = 0;
+  while (true) {
+    if (__value < __base)
+      return __r + 1;
+    if (__value < __base_2)
+      return __r + 2;
+    if (__value < __base_3)
+      return __r + 3;
+    if (__value < __base_4)
+      return __r + 4;
+
+    __value /= __base_4;
+    __r += 4;
+  }
+
+  _LIBCPP_UNREACHABLE();
+}
+
+template <typename _Tp>
+_LIBCPP_AVAILABILITY_TO_CHARS
+inline _LIBCPP_INLINE_VISIBILITY to_chars_result
+__to_chars_integral(char* __first, char* __last, _Tp __value, int __base,
+                    false_type)
+{
+  if (__base == 10)
+    return __to_chars_itoa(__first, __last, __value, false_type());
+
+  ptrdiff_t __cap = __last - __first;
+  int __n = __to_chars_integral_width(__value, __base);
+  if (__n > __cap)
+    return {__last, errc::value_too_large};
+
+  __last = __first + __n;
+  char* __p = __last;
+  do {
+    unsigned __c = __value % __base;
+    __value /= __base;
+    *--__p = "0123456789abcdefghijklmnopqrstuvwxyz"[__c];
+  } while (__value != 0);
+  return {__last, errc(0)};
+}
+
+template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0>
+_LIBCPP_AVAILABILITY_TO_CHARS
+inline _LIBCPP_INLINE_VISIBILITY to_chars_result
+to_chars(char* __first, char* __last, _Tp __value)
+{
+    return __to_chars_itoa(__first, __last, __value, is_signed<_Tp>());
+}
+
+template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0>
+_LIBCPP_AVAILABILITY_TO_CHARS
+inline _LIBCPP_INLINE_VISIBILITY to_chars_result
+to_chars(char* __first, char* __last, _Tp __value, int __base)
+{
+    _LIBCPP_ASSERT(2 <= __base && __base <= 36, "base not in [2, 36]");
+    return __to_chars_integral(__first, __last, __value, __base,
+                               is_signed<_Tp>());
+}
+
+template <typename _It, typename _Tp, typename _Fn, typename... _Ts>
+inline _LIBCPP_INLINE_VISIBILITY from_chars_result
+__sign_combinator(_It __first, _It __last, _Tp& __value, _Fn __f, _Ts... __args)
+{
+    using __tl = numeric_limits<_Tp>;
+    decltype(__to_unsigned_like(__value)) __x;
+
+    bool __neg = (__first != __last && *__first == '-');
+    auto __r = __f(__neg ? __first + 1 : __first, __last, __x, __args...);
+    switch (__r.ec)
+    {
+    case errc::invalid_argument:
+        return {__first, __r.ec};
+    case errc::result_out_of_range:
+        return __r;
+    default:
+        break;
+    }
+
+    if (__neg)
+    {
+        if (__x <= __complement(__to_unsigned_like(__tl::min())))
+        {
+            __x = __complement(__x);
+            _VSTD::memcpy(&__value, &__x, sizeof(__x));
+            return __r;
+        }
+    }
+    else
+    {
+        if (__x <= __tl::max())
+        {
+            __value = __x;
+            return __r;
+        }
+    }
+
+    return {__r.ptr, errc::result_out_of_range};
+}
+
+template <typename _Tp>
+inline _LIBCPP_INLINE_VISIBILITY bool
+__in_pattern(_Tp __c)
+{
+    return '0' <= __c && __c <= '9';
+}
+
+struct _LIBCPP_HIDDEN __in_pattern_result
+{
+    bool __ok;
+    int __val;
+
+    explicit _LIBCPP_INLINE_VISIBILITY operator bool() const { return __ok; }
+};
+
+template <typename _Tp>
+inline _LIBCPP_INLINE_VISIBILITY __in_pattern_result
+__in_pattern(_Tp __c, int __base)
+{
+    if (__base <= 10)
+        return {'0' <= __c && __c < '0' + __base, __c - '0'};
+    else if (__in_pattern(__c))
+        return {true, __c - '0'};
+    else if ('a' <= __c && __c < 'a' + __base - 10)
+        return {true, __c - 'a' + 10};
+    else
+        return {'A' <= __c && __c < 'A' + __base - 10, __c - 'A' + 10};
+}
+
+template <typename _It, typename _Tp, typename _Fn, typename... _Ts>
+inline _LIBCPP_INLINE_VISIBILITY from_chars_result
+__subject_seq_combinator(_It __first, _It __last, _Tp& __value, _Fn __f,
+                         _Ts... __args)
+{
+    auto __find_non_zero = [](_It __first, _It __last) {
+        for (; __first != __last; ++__first)
+            if (*__first != '0')
+                break;
+        return __first;
+    };
+
+    auto __p = __find_non_zero(__first, __last);
+    if (__p == __last || !__in_pattern(*__p, __args...))
+    {
+        if (__p == __first)
+            return {__first, errc::invalid_argument};
+        else
+        {
+            __value = 0;
+            return {__p, {}};
+        }
+    }
+
+    auto __r = __f(__p, __last, __value, __args...);
+    if (__r.ec == errc::result_out_of_range)
+    {
+        for (; __r.ptr != __last; ++__r.ptr)
+        {
+            if (!__in_pattern(*__r.ptr, __args...))
+                break;
+        }
+    }
+
+    return __r;
+}
+
+template <typename _Tp, typename enable_if<is_unsigned<_Tp>::value, int>::type = 0>
+inline _LIBCPP_INLINE_VISIBILITY from_chars_result
+__from_chars_atoi(const char* __first, const char* __last, _Tp& __value)
+{
+    using __tx = __itoa::__traits<_Tp>;
+    using __output_type = typename __tx::type;
+
+    return __subject_seq_combinator(
+        __first, __last, __value,
+        [](const char* __first, const char* __last,
+           _Tp& __value) -> from_chars_result {
+            __output_type __a, __b;
+            auto __p = __tx::__read(__first, __last, __a, __b);
+            if (__p == __last || !__in_pattern(*__p))
+            {
+                __output_type __m = numeric_limits<_Tp>::max();
+                if (__m >= __a && __m - __a >= __b)
+                {
+                    __value = __a + __b;
+                    return {__p, {}};
+                }
+            }
+            return {__p, errc::result_out_of_range};
+        });
+}
+
+template <typename _Tp, typename enable_if<is_signed<_Tp>::value, int>::type = 0>
+inline _LIBCPP_INLINE_VISIBILITY from_chars_result
+__from_chars_atoi(const char* __first, const char* __last, _Tp& __value)
+{
+    using __t = decltype(__to_unsigned_like(__value));
+    return __sign_combinator(__first, __last, __value, __from_chars_atoi<__t>);
+}
+
+template <typename _Tp, typename enable_if<is_unsigned<_Tp>::value, int>::type = 0>
+inline _LIBCPP_INLINE_VISIBILITY from_chars_result
+__from_chars_integral(const char* __first, const char* __last, _Tp& __value,
+                      int __base)
+{
+    if (__base == 10)
+        return __from_chars_atoi(__first, __last, __value);
+
+    return __subject_seq_combinator(
+        __first, __last, __value,
+        [](const char* __p, const char* __lastx, _Tp& __value,
+           int __base) -> from_chars_result {
+            using __tl = numeric_limits<_Tp>;
+            auto __digits = __tl::digits / log2f(float(__base));
+            _Tp __a = __in_pattern(*__p++, __base).__val, __b = 0;
+
+            for (int __i = 1; __p != __lastx; ++__i, ++__p)
+            {
+                if (auto __c = __in_pattern(*__p, __base))
+                {
+                    if (__i < __digits - 1)
+                        __a = __a * __base + __c.__val;
+                    else
+                    {
+                        if (!__itoa::__mul_overflowed(__a, __base, __a))
+                            ++__p;
+                        __b = __c.__val;
+                        break;
+                    }
+                }
+                else
+                    break;
+            }
+
+            if (__p == __lastx || !__in_pattern(*__p, __base))
+            {
+                if (__tl::max() - __a >= __b)
+                {
+                    __value = __a + __b;
+                    return {__p, {}};
+                }
+            }
+            return {__p, errc::result_out_of_range};
+        },
+        __base);
+}
+
+template <typename _Tp, typename enable_if<is_signed<_Tp>::value, int>::type = 0>
+inline _LIBCPP_INLINE_VISIBILITY from_chars_result
+__from_chars_integral(const char* __first, const char* __last, _Tp& __value,
+                      int __base)
+{
+    using __t = decltype(__to_unsigned_like(__value));
+    return __sign_combinator(__first, __last, __value,
+                             __from_chars_integral<__t>, __base);
+}
+
+template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0>
+inline _LIBCPP_INLINE_VISIBILITY from_chars_result
+from_chars(const char* __first, const char* __last, _Tp& __value)
+{
+    return __from_chars_atoi(__first, __last, __value);
+}
+
+template <typename _Tp, typename enable_if<is_integral<_Tp>::value, int>::type = 0>
+inline _LIBCPP_INLINE_VISIBILITY from_chars_result
+from_chars(const char* __first, const char* __last, _Tp& __value, int __base)
+{
+    _LIBCPP_ASSERT(2 <= __base && __base <= 36, "base not in [2, 36]");
+    return __from_chars_integral(__first, __last, __value, __base);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_CHARCONV
diff --git a/contrib/libs/cxxsupp/libcxx/include/chrono b/contrib/libs/cxxsupp/libcxx/include/chrono
new file mode 100644
index 00000000000..db186a4fba1
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/chrono
@@ -0,0 +1,2977 @@
+// -*- C++ -*-
+//===---------------------------- chrono ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CHRONO
+#define _LIBCPP_CHRONO
+
+/*
+    chrono synopsis
+
+namespace std
+{
+namespace chrono
+{
+
+template <class ToDuration, class Rep, class Period>
+constexpr
+ToDuration
+duration_cast(const duration<Rep, Period>& fd);
+
+template <class Rep> struct treat_as_floating_point : is_floating_point<Rep> {};
+
+template <class Rep> inline constexpr bool treat_as_floating_point_v
+    = treat_as_floating_point<Rep>::value;                       // C++17
+
+template <class Rep>
+struct duration_values
+{
+public:
+    static constexpr Rep zero(); // noexcept in C++20
+    static constexpr Rep max();  // noexcept in C++20
+    static constexpr Rep min();  // noexcept in C++20
+};
+
+// duration
+
+template <class Rep, class Period = ratio<1>>
+class duration
+{
+    static_assert(!__is_duration<Rep>::value, "A duration representation can not be a duration");
+    static_assert(__is_ratio<Period>::value, "Second template parameter of duration must be a std::ratio");
+    static_assert(Period::num > 0, "duration period must be positive");
+public:
+    typedef Rep rep;
+    typedef typename _Period::type period;
+
+    constexpr duration() = default;
+    template <class Rep2>
+        constexpr explicit duration(const Rep2& r,
+            typename enable_if
+            <
+               is_convertible<Rep2, rep>::value &&
+               (treat_as_floating_point<rep>::value ||
+               !treat_as_floating_point<rep>::value && !treat_as_floating_point<Rep2>::value)
+            >::type* = 0);
+
+    // conversions
+    template <class Rep2, class Period2>
+        constexpr duration(const duration<Rep2, Period2>& d,
+            typename enable_if
+            <
+                treat_as_floating_point<rep>::value ||
+                ratio_divide<Period2, period>::type::den == 1
+            >::type* = 0);
+
+    // observer
+
+    constexpr rep count() const;
+
+    // arithmetic
+
+    constexpr common_type<duration>::type  operator+() const;
+    constexpr common_type<duration>::type  operator-() const;
+    constexpr duration& operator++();    // constexpr in C++17
+    constexpr duration  operator++(int); // constexpr in C++17
+    constexpr duration& operator--();    // constexpr in C++17
+    constexpr duration  operator--(int); // constexpr in C++17
+
+    constexpr duration& operator+=(const duration& d);  // constexpr in C++17
+    constexpr duration& operator-=(const duration& d);  // constexpr in C++17
+
+    duration& operator*=(const rep& rhs);       // constexpr in C++17
+    duration& operator/=(const rep& rhs);       // constexpr in C++17
+    duration& operator%=(const rep& rhs);       // constexpr in C++17
+    duration& operator%=(const duration& rhs);  // constexpr in C++17
+
+    // special values
+
+    static constexpr duration zero(); // noexcept in C++20
+    static constexpr duration min();  // noexcept in C++20
+    static constexpr duration max();  // noexcept in C++20
+};
+
+typedef duration<long long,         nano> nanoseconds;
+typedef duration<long long,        micro> microseconds;
+typedef duration<long long,        milli> milliseconds;
+typedef duration<long long              > seconds;
+typedef duration<     long, ratio<  60> > minutes;
+typedef duration<     long, ratio<3600> > hours;
+
+template <class Clock, class Duration = typename Clock::duration>
+class time_point
+{
+public:
+    typedef Clock                     clock;
+    typedef Duration                  duration;
+    typedef typename duration::rep    rep;
+    typedef typename duration::period period;
+private:
+    duration d_;  // exposition only
+
+public:
+    time_point();  // has value "epoch" // constexpr in C++14
+    explicit time_point(const duration& d);  // same as time_point() + d // constexpr in C++14
+
+    // conversions
+    template <class Duration2>
+       time_point(const time_point<clock, Duration2>& t); // constexpr in C++14
+
+    // observer
+
+    duration time_since_epoch() const; // constexpr in C++14
+
+    // arithmetic
+
+    time_point& operator+=(const duration& d); // constexpr in C++17
+    time_point& operator-=(const duration& d); // constexpr in C++17
+
+    // special values
+
+    static constexpr time_point min();  // noexcept in C++20
+    static constexpr time_point max();  // noexcept in C++20
+};
+
+} // chrono
+
+// common_type traits
+template <class Rep1, class Period1, class Rep2, class Period2>
+  struct common_type<chrono::duration<Rep1, Period1>, chrono::duration<Rep2, Period2>>;
+
+template <class Clock, class Duration1, class Duration2>
+  struct common_type<chrono::time_point<Clock, Duration1>, chrono::time_point<Clock, Duration2>>;
+
+namespace chrono {
+
+
+template<class T> struct is_clock;  // C++20
+template<class T> inline constexpr bool is_clock_v = is_clock<T>::value;   // C++20
+
+
+// duration arithmetic
+template <class Rep1, class Period1, class Rep2, class Period2>
+  constexpr
+  typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
+  operator+(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+  constexpr
+  typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
+  operator-(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period, class Rep2>
+  constexpr
+  duration<typename common_type<Rep1, Rep2>::type, Period>
+  operator*(const duration<Rep1, Period>& d, const Rep2& s);
+template <class Rep1, class Period, class Rep2>
+  constexpr
+  duration<typename common_type<Rep1, Rep2>::type, Period>
+  operator*(const Rep1& s, const duration<Rep2, Period>& d);
+template <class Rep1, class Period, class Rep2>
+  constexpr
+  duration<typename common_type<Rep1, Rep2>::type, Period>
+  operator/(const duration<Rep1, Period>& d, const Rep2& s);
+template <class Rep1, class Period1, class Rep2, class Period2>
+  constexpr
+  typename common_type<Rep1, Rep2>::type
+  operator/(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+
+// duration comparisons
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr
+   bool operator==(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr
+   bool operator!=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr
+   bool operator< (const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr
+   bool operator<=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr
+   bool operator> (const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Rep2, class Period2>
+   constexpr
+   bool operator>=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
+
+// duration_cast
+template <class ToDuration, class Rep, class Period>
+  ToDuration duration_cast(const duration<Rep, Period>& d);
+
+template <class ToDuration, class Rep, class Period>
+    constexpr ToDuration floor(const duration<Rep, Period>& d);    // C++17
+template <class ToDuration, class Rep, class Period>
+    constexpr ToDuration ceil(const duration<Rep, Period>& d);     // C++17
+template <class ToDuration, class Rep, class Period>
+    constexpr ToDuration round(const duration<Rep, Period>& d);    // C++17
+
+// duration I/O is elsewhere
+
+// time_point arithmetic (all constexpr in C++14)
+template <class Clock, class Duration1, class Rep2, class Period2>
+  time_point<Clock, typename common_type<Duration1, duration<Rep2, Period2>>::type>
+  operator+(const time_point<Clock, Duration1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Rep1, class Period1, class Clock, class Duration2>
+  time_point<Clock, typename common_type<duration<Rep1, Period1>, Duration2>::type>
+  operator+(const duration<Rep1, Period1>& lhs, const time_point<Clock, Duration2>& rhs);
+template <class Clock, class Duration1, class Rep2, class Period2>
+  time_point<Clock, typename common_type<Duration1, duration<Rep2, Period2>>::type>
+  operator-(const time_point<Clock, Duration1>& lhs, const duration<Rep2, Period2>& rhs);
+template <class Clock, class Duration1, class Duration2>
+  typename common_type<Duration1, Duration2>::type
+  operator-(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+
+// time_point comparisons (all constexpr in C++14)
+template <class Clock, class Duration1, class Duration2>
+   bool operator==(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+template <class Clock, class Duration1, class Duration2>
+   bool operator!=(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+template <class Clock, class Duration1, class Duration2>
+   bool operator< (const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+template <class Clock, class Duration1, class Duration2>
+   bool operator<=(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+template <class Clock, class Duration1, class Duration2>
+   bool operator> (const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+template <class Clock, class Duration1, class Duration2>
+   bool operator>=(const time_point<Clock, Duration1>& lhs, const time_point<Clock, Duration2>& rhs);
+
+// time_point_cast (constexpr in C++14)
+
+template <class ToDuration, class Clock, class Duration>
+  time_point<Clock, ToDuration> time_point_cast(const time_point<Clock, Duration>& t);
+
+template <class ToDuration, class Clock, class Duration>
+    constexpr time_point<Clock, ToDuration>
+    floor(const time_point<Clock, Duration>& tp);                  // C++17
+
+template <class ToDuration, class Clock, class Duration>
+    constexpr time_point<Clock, ToDuration>
+    ceil(const time_point<Clock, Duration>& tp);                   // C++17
+
+template <class ToDuration, class Clock, class Duration>
+    constexpr time_point<Clock, ToDuration>
+    round(const time_point<Clock, Duration>& tp);                  // C++17
+
+template <class Rep, class Period>
+    constexpr duration<Rep, Period> abs(duration<Rep, Period> d);  // C++17
+
+// Clocks
+
+class system_clock
+{
+public:
+    typedef microseconds                     duration;
+    typedef duration::rep                    rep;
+    typedef duration::period                 period;
+    typedef chrono::time_point<system_clock> time_point;
+    static const bool is_steady =            false; // constexpr in C++14
+
+    static time_point now() noexcept;
+    static time_t     to_time_t  (const time_point& __t) noexcept;
+    static time_point from_time_t(time_t __t) noexcept;
+};
+
+template <class Duration>
+  using sys_time  = time_point<system_clock, Duration>; // C++20
+using sys_seconds = sys_time<seconds>;                  // C++20
+using sys_days    = sys_time<days>;                     // C++20
+
+class utc_clock;                                        // C++20
+
+template <class Duration>
+  using utc_time  = time_point<utc_clock, Duration>;    // C++20
+using utc_seconds = utc_time<seconds>;                  // C++20
+
+class tai_clock;                                        // C++20
+
+template <class Duration>
+  using tai_time  = time_point<tai_clock, Duration>;    // C++20
+using tai_seconds = tai_time<seconds>;                  // C++20
+
+class file_clock;                                       // C++20
+
+template<class Duration>
+  using file_time = time_point<file_clock, Duration>;   // C++20
+
+class steady_clock
+{
+public:
+    typedef nanoseconds                                   duration;
+    typedef duration::rep                                 rep;
+    typedef duration::period                              period;
+    typedef chrono::time_point<steady_clock, duration>    time_point;
+    static const bool is_steady =                         true; // constexpr in C++14
+
+    static time_point now() noexcept;
+};
+
+typedef steady_clock high_resolution_clock;
+
+// 25.7.8, local time           // C++20
+struct local_t {};
+template<class Duration>
+  using local_time  = time_point<local_t, Duration>;
+using local_seconds = local_time<seconds>;
+using local_days    = local_time<days>;
+
+// 25.7.9, time_point conversions template<class DestClock, class SourceClock>    // C++20
+struct clock_time_conversion;
+
+template<class DestClock, class SourceClock, class Duration>
+  auto clock_cast(const time_point<SourceClock, Duration>& t);
+
+// 25.8.2, class last_spec    // C++20
+struct last_spec;
+
+// 25.8.3, class day          // C++20
+
+class day;
+constexpr bool operator==(const day& x, const day& y) noexcept;
+constexpr bool operator!=(const day& x, const day& y) noexcept;
+constexpr bool operator< (const day& x, const day& y) noexcept;
+constexpr bool operator> (const day& x, const day& y) noexcept;
+constexpr bool operator<=(const day& x, const day& y) noexcept;
+constexpr bool operator>=(const day& x, const day& y) noexcept;
+constexpr day  operator+(const day&  x, const days& y) noexcept;
+constexpr day  operator+(const days& x, const day&  y) noexcept;
+constexpr day  operator-(const day&  x, const days& y) noexcept;
+constexpr days operator-(const day&  x, const day&  y) noexcept;
+
+// 25.8.4, class month    // C++20
+class month;
+constexpr bool operator==(const month& x, const month& y) noexcept;
+constexpr bool operator!=(const month& x, const month& y) noexcept;
+constexpr bool operator< (const month& x, const month& y) noexcept;
+constexpr bool operator> (const month& x, const month& y) noexcept;
+constexpr bool operator<=(const month& x, const month& y) noexcept;
+constexpr bool operator>=(const month& x, const month& y) noexcept;
+constexpr month  operator+(const month&  x, const months& y) noexcept;
+constexpr month  operator+(const months& x,  const month& y) noexcept;
+constexpr month  operator-(const month&  x, const months& y) noexcept;
+constexpr months operator-(const month&  x,  const month& y) noexcept;
+
+// 25.8.5, class year    // C++20
+class year;
+constexpr bool operator==(const year& x, const year& y) noexcept;
+constexpr bool operator!=(const year& x, const year& y) noexcept;
+constexpr bool operator< (const year& x, const year& y) noexcept;
+constexpr bool operator> (const year& x, const year& y) noexcept;
+constexpr bool operator<=(const year& x, const year& y) noexcept;
+constexpr bool operator>=(const year& x, const year& y) noexcept;
+constexpr year  operator+(const year&  x, const years& y) noexcept;
+constexpr year  operator+(const years& x, const year&  y) noexcept;
+constexpr year  operator-(const year&  x, const years& y) noexcept;
+constexpr years operator-(const year&  x, const year&  y) noexcept;
+
+// 25.8.6, class weekday    // C++20
+class weekday;
+
+constexpr bool operator==(const weekday& x, const weekday& y) noexcept;
+constexpr bool operator!=(const weekday& x, const weekday& y) noexcept;
+constexpr weekday operator+(const weekday& x, const days&    y) noexcept;
+constexpr weekday operator+(const days&    x, const weekday& y) noexcept;
+constexpr weekday operator-(const weekday& x, const days&    y) noexcept;
+constexpr days    operator-(const weekday& x, const weekday& y) noexcept;
+
+// 25.8.7, class weekday_indexed    // C++20
+
+class weekday_indexed;
+constexpr bool operator==(const weekday_indexed& x, const weekday_indexed& y) noexcept;
+constexpr bool operator!=(const weekday_indexed& x, const weekday_indexed& y) noexcept;
+
+// 25.8.8, class weekday_last    // C++20
+class weekday_last;
+
+constexpr bool operator==(const weekday_last& x, const weekday_last& y) noexcept;
+constexpr bool operator!=(const weekday_last& x, const weekday_last& y) noexcept;
+
+// 25.8.9, class month_day    // C++20
+class month_day;
+
+constexpr bool operator==(const month_day& x, const month_day& y) noexcept;
+constexpr bool operator!=(const month_day& x, const month_day& y) noexcept;
+constexpr bool operator< (const month_day& x, const month_day& y) noexcept;
+constexpr bool operator> (const month_day& x, const month_day& y) noexcept;
+constexpr bool operator<=(const month_day& x, const month_day& y) noexcept;
+constexpr bool operator>=(const month_day& x, const month_day& y) noexcept;
+
+
+// 25.8.10, class month_day_last    // C++20
+class month_day_last;
+
+constexpr bool operator==(const month_day_last& x, const month_day_last& y) noexcept;
+constexpr bool operator!=(const month_day_last& x, const month_day_last& y) noexcept;
+constexpr bool operator< (const month_day_last& x, const month_day_last& y) noexcept;
+constexpr bool operator> (const month_day_last& x, const month_day_last& y) noexcept;
+constexpr bool operator<=(const month_day_last& x, const month_day_last& y) noexcept;
+constexpr bool operator>=(const month_day_last& x, const month_day_last& y) noexcept;
+
+// 25.8.11, class month_weekday    // C++20
+class month_weekday;
+
+constexpr bool operator==(const month_weekday& x, const month_weekday& y) noexcept;
+constexpr bool operator!=(const month_weekday& x, const month_weekday& y) noexcept;
+
+// 25.8.12, class month_weekday_last    // C++20
+class month_weekday_last;
+
+constexpr bool operator==(const month_weekday_last& x, const month_weekday_last& y) noexcept;
+constexpr bool operator!=(const month_weekday_last& x, const month_weekday_last& y) noexcept;
+
+
+// 25.8.13, class year_month    // C++20
+class year_month;
+
+constexpr bool operator==(const year_month& x, const year_month& y) noexcept;
+constexpr bool operator!=(const year_month& x, const year_month& y) noexcept;
+constexpr bool operator< (const year_month& x, const year_month& y) noexcept;
+constexpr bool operator> (const year_month& x, const year_month& y) noexcept;
+constexpr bool operator<=(const year_month& x, const year_month& y) noexcept;
+constexpr bool operator>=(const year_month& x, const year_month& y) noexcept;
+
+constexpr year_month operator+(const year_month& ym, const months& dm) noexcept;
+constexpr year_month operator+(const months& dm, const year_month& ym) noexcept;
+constexpr year_month operator-(const year_month& ym, const months& dm) noexcept;
+constexpr months operator-(const year_month& x, const year_month& y) noexcept;
+constexpr year_month operator+(const year_month& ym, const years& dy) noexcept;
+constexpr year_month operator+(const years& dy, const year_month& ym) noexcept;
+constexpr year_month operator-(const year_month& ym, const years& dy) noexcept;
+
+// 25.8.14, class year_month_day class    // C++20
+year_month_day;
+
+constexpr bool operator==(const year_month_day& x, const year_month_day& y) noexcept;
+constexpr bool operator!=(const year_month_day& x, const year_month_day& y) noexcept;
+constexpr bool operator< (const year_month_day& x, const year_month_day& y) noexcept;
+constexpr bool operator> (const year_month_day& x, const year_month_day& y) noexcept;
+constexpr bool operator<=(const year_month_day& x, const year_month_day& y) noexcept;
+constexpr bool operator>=(const year_month_day& x, const year_month_day& y) noexcept;
+
+constexpr year_month_day operator+(const year_month_day& ymd, const months& dm) noexcept;
+constexpr year_month_day operator+(const months& dm, const year_month_day& ymd) noexcept;
+constexpr year_month_day operator+(const year_month_day& ymd, const years& dy) noexcept;
+constexpr year_month_day operator+(const years& dy, const year_month_day& ymd) noexcept;
+constexpr year_month_day operator-(const year_month_day& ymd, const months& dm) noexcept;
+constexpr year_month_day operator-(const year_month_day& ymd, const years& dy) noexcept;
+
+
+// 25.8.15, class year_month_day_last    // C++20
+class year_month_day_last;
+
+constexpr bool operator==(const year_month_day_last& x,
+                          const year_month_day_last& y) noexcept;
+constexpr bool operator!=(const year_month_day_last& x,
+                          const year_month_day_last& y) noexcept;
+constexpr bool operator< (const year_month_day_last& x,
+                          const year_month_day_last& y) noexcept;
+constexpr bool operator> (const year_month_day_last& x,
+                          const year_month_day_last& y) noexcept;
+constexpr bool operator<=(const year_month_day_last& x,
+                          const year_month_day_last& y) noexcept;
+constexpr bool operator>=(const year_month_day_last& x,
+                          const year_month_day_last& y) noexcept;
+
+constexpr year_month_day_last
+  operator+(const year_month_day_last& ymdl, const months& dm) noexcept;
+constexpr year_month_day_last
+  operator+(const months& dm, const year_month_day_last& ymdl) noexcept;
+constexpr year_month_day_last
+  operator+(const year_month_day_last& ymdl, const years& dy) noexcept;
+constexpr year_month_day_last
+  operator+(const years& dy, const year_month_day_last& ymdl) noexcept;
+constexpr year_month_day_last
+  operator-(const year_month_day_last& ymdl, const months& dm) noexcept;
+constexpr year_month_day_last
+  operator-(const year_month_day_last& ymdl, const years& dy) noexcept;
+
+// 25.8.16, class year_month_weekday    // C++20
+class year_month_weekday;
+
+constexpr bool operator==(const year_month_weekday& x,
+                          const year_month_weekday& y) noexcept;
+constexpr bool operator!=(const year_month_weekday& x,
+                          const year_month_weekday& y) noexcept;
+
+constexpr year_month_weekday
+  operator+(const year_month_weekday& ymwd, const months& dm) noexcept;
+constexpr year_month_weekday
+  operator+(const months& dm, const year_month_weekday& ymwd) noexcept;
+constexpr year_month_weekday
+  operator+(const year_month_weekday& ymwd, const years& dy) noexcept;
+constexpr year_month_weekday
+  operator+(const years& dy, const year_month_weekday& ymwd) noexcept;
+constexpr year_month_weekday
+  operator-(const year_month_weekday& ymwd, const months& dm) noexcept;
+constexpr year_month_weekday
+  operator-(const year_month_weekday& ymwd, const years& dy) noexcept;
+
+// 25.8.17, class year_month_weekday_last    // C++20
+class year_month_weekday_last;
+
+constexpr bool operator==(const year_month_weekday_last& x,
+                          const year_month_weekday_last& y) noexcept;
+constexpr bool operator!=(const year_month_weekday_last& x,
+                          const year_month_weekday_last& y) noexcept;
+constexpr year_month_weekday_last
+  operator+(const year_month_weekday_last& ymwdl, const months& dm) noexcept;
+constexpr year_month_weekday_last
+  operator+(const months& dm, const year_month_weekday_last& ymwdl) noexcept;
+constexpr year_month_weekday_last
+  operator+(const year_month_weekday_last& ymwdl, const years& dy) noexcept;
+constexpr year_month_weekday_last
+  operator+(const years& dy, const year_month_weekday_last& ymwdl) noexcept;
+constexpr year_month_weekday_last
+  operator-(const year_month_weekday_last& ymwdl, const months& dm) noexcept;
+constexpr year_month_weekday_last
+  operator-(const year_month_weekday_last& ymwdl, const years& dy) noexcept;
+
+// 25.8.18, civil calendar conventional syntax operators    // C++20
+constexpr year_month
+  operator/(const year& y, const month& m) noexcept;
+constexpr year_month
+  operator/(const year& y, int m) noexcept;
+constexpr month_day
+  operator/(const month& m, const day& d) noexcept;
+constexpr month_day
+  operator/(const month& m, int d) noexcept;
+constexpr month_day
+  operator/(int m, const day& d) noexcept;
+constexpr month_day
+  operator/(const day& d, const month& m) noexcept;
+constexpr month_day
+  operator/(const day& d, int m) noexcept;
+constexpr month_day_last
+  operator/(const month& m, last_spec) noexcept;
+constexpr month_day_last
+  operator/(int m, last_spec) noexcept;
+constexpr month_day_last
+  operator/(last_spec, const month& m) noexcept;
+constexpr month_day_last
+  operator/(last_spec, int m) noexcept;
+constexpr month_weekday
+  operator/(const month& m, const weekday_indexed& wdi) noexcept;
+constexpr month_weekday
+  operator/(int m, const weekday_indexed& wdi) noexcept;
+constexpr month_weekday
+  operator/(const weekday_indexed& wdi, const month& m) noexcept;
+constexpr month_weekday
+  operator/(const weekday_indexed& wdi, int m) noexcept;
+constexpr month_weekday_last
+  operator/(const month& m, const weekday_last& wdl) noexcept;
+constexpr month_weekday_last
+  operator/(int m, const weekday_last& wdl) noexcept;
+constexpr month_weekday_last
+  operator/(const weekday_last& wdl, const month& m) noexcept;
+constexpr month_weekday_last
+  operator/(const weekday_last& wdl, int m) noexcept;
+constexpr year_month_day
+  operator/(const year_month& ym, const day& d) noexcept;
+constexpr year_month_day
+  operator/(const year_month& ym, int d) noexcept;
+constexpr year_month_day
+  operator/(const year& y, const month_day& md) noexcept;
+constexpr year_month_day
+  operator/(int y, const month_day& md) noexcept;
+constexpr year_month_day
+  operator/(const month_day& md, const year& y) noexcept;
+constexpr year_month_day
+  operator/(const month_day& md, int y) noexcept;
+constexpr year_month_day_last
+  operator/(const year_month& ym, last_spec) noexcept;
+constexpr year_month_day_last
+  operator/(const year& y, const month_day_last& mdl) noexcept;
+constexpr year_month_day_last
+  operator/(int y, const month_day_last& mdl) noexcept;
+constexpr year_month_day_last
+  operator/(const month_day_last& mdl, const year& y) noexcept;
+constexpr year_month_day_last
+  operator/(const month_day_last& mdl, int y) noexcept;
+constexpr year_month_weekday
+  operator/(const year_month& ym, const weekday_indexed& wdi) noexcept;
+constexpr year_month_weekday
+  operator/(const year& y, const month_weekday& mwd) noexcept;
+constexpr year_month_weekday
+  operator/(int y, const month_weekday& mwd) noexcept;
+constexpr year_month_weekday
+  operator/(const month_weekday& mwd, const year& y) noexcept;
+constexpr year_month_weekday
+  operator/(const month_weekday& mwd, int y) noexcept;
+constexpr year_month_weekday_last
+  operator/(const year_month& ym, const weekday_last& wdl) noexcept;
+constexpr year_month_weekday_last
+  operator/(const year& y, const month_weekday_last& mwdl) noexcept;
+constexpr year_month_weekday_last
+  operator/(int y, const month_weekday_last& mwdl) noexcept;
+constexpr year_month_weekday_last
+  operator/(const month_weekday_last& mwdl, const year& y) noexcept;
+constexpr year_month_weekday_last
+  operator/(const month_weekday_last& mwdl, int y) noexcept;
+
+// 26.9, class template hh_mm_ss
+template <class Duration>
+class hh_mm_ss
+{
+    bool            is_neg; // exposition only
+    chrono::hours   h;      // exposition only
+    chrono::minutes m;      // exposition only
+    chrono::seconds s;      // exposition only
+    precision       ss;     // exposition only
+
+public:
+    static unsigned constexpr fractional_width = see below;
+    using precision                            = see below;
+
+    constexpr hh_mm_ss() noexcept : hh_mm_ss{Duration::zero()} {}
+    constexpr explicit hh_mm_ss(Duration d) noexcept;
+
+    constexpr bool is_negative() const noexcept;
+    constexpr chrono::hours hours() const noexcept;
+    constexpr chrono::minutes minutes() const noexcept;
+    constexpr chrono::seconds seconds() const noexcept;
+    constexpr precision subseconds() const noexcept;
+
+    constexpr explicit operator  precision()   const noexcept;
+    constexpr          precision to_duration() const noexcept;
+};
+
+template <class charT, class traits, class Duration>
+  basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os, hh_mm_ss<Duration> const& hms);
+
+// 26.10, 12/24 hour functions
+constexpr bool is_am(hours const& h) noexcept;
+constexpr bool is_pm(hours const& h) noexcept;
+constexpr hours make12(const hours& h) noexcept;
+constexpr hours make24(const hours& h, bool is_pm) noexcept;
+
+
+// 25.10.2, time zone database     // C++20
+struct tzdb;
+class tzdb_list;
+
+// 25.10.2.3, time zone database access    // C++20
+const tzdb& get_tzdb();
+tzdb_list& get_tzdb_list();
+const time_zone* locate_zone(string_view tz_name);
+const time_zone* current_zone();
+
+// 25.10.2.4, remote time zone database support    // C++20
+const tzdb& reload_tzdb();
+string remote_version();
+
+// 25.10.3, exception classes    // C++20
+class nonexistent_local_time;
+class ambiguous_local_time;
+
+// 25.10.4, information classes    // C++20
+struct sys_info;
+struct local_info;
+
+// 25.10.5, class time_zone    // C++20
+enum class choose {earliest, latest};
+class time_zone;
+bool operator==(const time_zone& x, const time_zone& y) noexcept;
+bool operator!=(const time_zone& x, const time_zone& y) noexcept;
+bool operator<(const time_zone& x, const time_zone& y) noexcept;
+bool operator>(const time_zone& x, const time_zone& y) noexcept;
+bool operator<=(const time_zone& x, const time_zone& y) noexcept;
+bool operator>=(const time_zone& x, const time_zone& y) noexcept;
+
+// 25.10.6, class template zoned_traits    // C++20
+template<class T> struct zoned_traits;
+
+// 25.10.7, class template zoned_time    // C++20
+template<class Duration, class TimeZonePtr = const time_zone*> class zoned_time;
+using zoned_seconds = zoned_time<seconds>;
+
+template<class Duration1, class Duration2, class TimeZonePtr>
+  bool operator==(const zoned_time<Duration1, TimeZonePtr>& x,
+                  const zoned_time<Duration2, TimeZonePtr>& y);
+template<class Duration1, class Duration2, class TimeZonePtr>
+  bool operator!=(const zoned_time<Duration1, TimeZonePtr>& x,
+                  const zoned_time<Duration2, TimeZonePtr>& y);
+
+// 25.10.8, leap second support    // C++20
+class leap;
+
+bool operator==(const leap& x, const leap& y);
+bool operator!=(const leap& x, const leap& y);
+bool operator< (const leap& x, const leap& y);
+bool operator> (const leap& x, const leap& y);
+bool operator<=(const leap& x, const leap& y);
+bool operator>=(const leap& x, const leap& y);
+template<class Duration>
+  bool operator==(const leap& x, const sys_time<Duration>& y);
+template<class Duration>
+  bool operator==(const sys_time<Duration>& x, const leap& y);
+template<class Duration>
+  bool operator!=(const leap& x, const sys_time<Duration>& y);
+template<class Duration>
+  bool operator!=(const sys_time<Duration>& x, const leap& y);
+template<class Duration>
+  bool operator< (const leap& x, const sys_time<Duration>& y);
+template<class Duration>
+  bool operator< (const sys_time<Duration>& x, const leap& y);
+template<class Duration>
+  bool operator> (const leap& x, const sys_time<Duration>& y);
+template<class Duration>
+  bool operator> (const sys_time<Duration>& x, const leap& y);
+template<class Duration>
+  bool operator<=(const leap& x, const sys_time<Duration>& y);
+template<class Duration>
+  bool operator<=(const sys_time<Duration>& x, const leap& y);
+template<class Duration>
+  bool operator>=(const leap& x, const sys_time<Duration>& y);
+template<class Duration>
+  bool operator>=(const sys_time<Duration>& x, const leap& y);
+
+// 25.10.9, class link    // C++20
+class link;
+bool operator==(const link& x, const link& y);
+bool operator!=(const link& x, const link& y);
+bool operator< (const link& x, const link& y);
+bool operator> (const link& x, const link& y);
+bool operator<=(const link& x, const link& y);
+bool operator>=(const link& x, const link& y);
+
+// 25.11, formatting    // C++20
+template<class charT, class Streamable>
+  basic_string<charT>
+    format(const charT* fmt, const Streamable& s);
+
+template<class charT, class Streamable>
+  basic_string<charT>
+    format(const locale& loc, const charT* fmt, const Streamable& s);
+
+template<class charT, class traits, class Alloc, class Streamable>
+  basic_string<charT, traits, Alloc>
+    format(const basic_string<charT, traits, Alloc>& fmt, const Streamable& s);
+
+template<class charT, class traits, class Alloc, class Streamable>
+  basic_string<charT, traits, Alloc>
+    format(const locale& loc, const basic_string<charT, traits, Alloc>& fmt,
+           const Streamable& s);
+
+// 25.12, parsing    // C++20
+template<class charT, class traits, class Alloc, class Parsable>
+unspecified
+    parse(const basic_string<charT, traits, Alloc>& format, Parsable& tp);
+
+template<class charT, class traits, class Alloc, class Parsable>
+unspecified
+    parse(const basic_string<charT, traits, Alloc>& format, Parsable& tp,
+          basic_string<charT, traits, Alloc>& abbrev);
+
+template<class charT, class traits, class Alloc, class Parsable>
+unspecified
+    parse(const basic_string<charT, traits, Alloc>& format, Parsable& tp,
+          minutes& offset);
+
+template<class charT, class traits, class Alloc, class Parsable>
+unspecified
+    parse(const basic_string<charT, traits, Alloc>& format, Parsable& tp,
+          basic_string<charT, traits, Alloc>& abbrev, minutes& offset);
+
+// calendrical constants
+inline constexpr last_spec                              last{};       // C++20
+inline constexpr chrono::weekday                        Sunday{0};    // C++20
+inline constexpr chrono::weekday                        Monday{1};    // C++20
+inline constexpr chrono::weekday                        Tuesday{2};   // C++20
+inline constexpr chrono::weekday                        Wednesday{3}; // C++20
+inline constexpr chrono::weekday                        Thursday{4};  // C++20
+inline constexpr chrono::weekday                        Friday{5};    // C++20
+inline constexpr chrono::weekday                        Saturday{6};  // C++20
+
+inline constexpr chrono::month                          January{1};   // C++20
+inline constexpr chrono::month                          February{2};  // C++20
+inline constexpr chrono::month                          March{3};     // C++20
+inline constexpr chrono::month                          April{4};     // C++20
+inline constexpr chrono::month                          May{5};       // C++20
+inline constexpr chrono::month                          June{6};      // C++20
+inline constexpr chrono::month                          July{7};      // C++20
+inline constexpr chrono::month                          August{8};    // C++20
+inline constexpr chrono::month                          September{9}; // C++20
+inline constexpr chrono::month                          October{10};  // C++20
+inline constexpr chrono::month                          November{11}; // C++20
+inline constexpr chrono::month                          December{12}; // C++20
+}  // chrono
+
+inline namespace literals {
+  inline namespace chrono_literals {
+constexpr chrono::hours                                 operator ""h(unsigned long long); // C++14
+constexpr chrono::duration<unspecified , ratio<3600,1>> operator ""h(long double); // C++14
+constexpr chrono::minutes                               operator ""min(unsigned long long); // C++14
+constexpr chrono::duration<unspecified , ratio<60,1>>   operator ""min(long double); // C++14
+constexpr chrono::seconds                               operator ""s(unsigned long long); // C++14
+constexpr chrono::duration<unspecified >                operator ""s(long double); // C++14
+constexpr chrono::milliseconds                          operator ""ms(unsigned long long); // C++14
+constexpr chrono::duration<unspecified , milli>         operator ""ms(long double); // C++14
+constexpr chrono::microseconds                          operator ""us(unsigned long long); // C++14
+constexpr chrono::duration<unspecified , micro>         operator ""us(long double); // C++14
+constexpr chrono::nanoseconds                           operator ""ns(unsigned long long); // C++14
+constexpr chrono::duration<unspecified , nano>          operator ""ns(long double); // C++14
+constexpr chrono::day                                   operator ""d(unsigned long long d) noexcept; // C++20
+constexpr chrono::year                                  operator ""y(unsigned long long y) noexcept; // C++20
+}  // chrono_literals
+}  // literals
+
+}  // std
+*/
+
+#include <__availability>
+#include <__config>
+#include <compare>
+#include <ctime>
+#include <limits>
+#include <ratio>
+#include <type_traits>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4455)
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+struct _FilesystemClock;
+_LIBCPP_END_NAMESPACE_FILESYSTEM
+#endif // !_LIBCPP_CXX03_LANG
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace chrono
+{
+
+template <class _Rep, class _Period = ratio<1> > class _LIBCPP_TEMPLATE_VIS duration;
+
+template <class _Tp>
+struct __is_duration : false_type {};
+
+template <class _Rep, class _Period>
+struct __is_duration<duration<_Rep, _Period> > : true_type  {};
+
+template <class _Rep, class _Period>
+struct __is_duration<const duration<_Rep, _Period> > : true_type  {};
+
+template <class _Rep, class _Period>
+struct __is_duration<volatile duration<_Rep, _Period> > : true_type  {};
+
+template <class _Rep, class _Period>
+struct __is_duration<const volatile duration<_Rep, _Period> > : true_type  {};
+
+} // chrono
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+struct _LIBCPP_TEMPLATE_VIS common_type<chrono::duration<_Rep1, _Period1>,
+                                         chrono::duration<_Rep2, _Period2> >
+{
+    typedef chrono::duration<typename common_type<_Rep1, _Rep2>::type,
+                             typename __ratio_gcd<_Period1, _Period2>::type> type;
+};
+
+namespace chrono {
+
+// duration_cast
+
+template <class _FromDuration, class _ToDuration,
+          class _Period = typename ratio_divide<typename _FromDuration::period, typename _ToDuration::period>::type,
+          bool = _Period::num == 1,
+          bool = _Period::den == 1>
+struct __duration_cast;
+
+template <class _FromDuration, class _ToDuration, class _Period>
+struct __duration_cast<_FromDuration, _ToDuration, _Period, true, true>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    _ToDuration operator()(const _FromDuration& __fd) const
+    {
+        return _ToDuration(static_cast<typename _ToDuration::rep>(__fd.count()));
+    }
+};
+
+template <class _FromDuration, class _ToDuration, class _Period>
+struct __duration_cast<_FromDuration, _ToDuration, _Period, true, false>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    _ToDuration operator()(const _FromDuration& __fd) const
+    {
+        typedef typename common_type<typename _ToDuration::rep, typename _FromDuration::rep, intmax_t>::type _Ct;
+        return _ToDuration(static_cast<typename _ToDuration::rep>(
+                           static_cast<_Ct>(__fd.count()) / static_cast<_Ct>(_Period::den)));
+    }
+};
+
+template <class _FromDuration, class _ToDuration, class _Period>
+struct __duration_cast<_FromDuration, _ToDuration, _Period, false, true>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    _ToDuration operator()(const _FromDuration& __fd) const
+    {
+        typedef typename common_type<typename _ToDuration::rep, typename _FromDuration::rep, intmax_t>::type _Ct;
+        return _ToDuration(static_cast<typename _ToDuration::rep>(
+                           static_cast<_Ct>(__fd.count()) * static_cast<_Ct>(_Period::num)));
+    }
+};
+
+template <class _FromDuration, class _ToDuration, class _Period>
+struct __duration_cast<_FromDuration, _ToDuration, _Period, false, false>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    _ToDuration operator()(const _FromDuration& __fd) const
+    {
+        typedef typename common_type<typename _ToDuration::rep, typename _FromDuration::rep, intmax_t>::type _Ct;
+        return _ToDuration(static_cast<typename _ToDuration::rep>(
+                           static_cast<_Ct>(__fd.count()) * static_cast<_Ct>(_Period::num)
+                                                          / static_cast<_Ct>(_Period::den)));
+    }
+};
+
+template <class _ToDuration, class _Rep, class _Period>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename enable_if
+<
+    __is_duration<_ToDuration>::value,
+    _ToDuration
+>::type
+duration_cast(const duration<_Rep, _Period>& __fd)
+{
+    return __duration_cast<duration<_Rep, _Period>, _ToDuration>()(__fd);
+}
+
+template <class _Rep>
+struct _LIBCPP_TEMPLATE_VIS treat_as_floating_point : is_floating_point<_Rep> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Rep>
+inline constexpr bool treat_as_floating_point_v = treat_as_floating_point<_Rep>::value;
+#endif
+
+template <class _Rep>
+struct _LIBCPP_TEMPLATE_VIS duration_values
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR _Rep zero() _NOEXCEPT {return _Rep(0);}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR _Rep max()  _NOEXCEPT {return numeric_limits<_Rep>::max();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR _Rep min()  _NOEXCEPT {return numeric_limits<_Rep>::lowest();}
+};
+
+#if _LIBCPP_STD_VER > 14
+template <class _ToDuration, class _Rep, class _Period>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename enable_if
+<
+    __is_duration<_ToDuration>::value,
+    _ToDuration
+>::type
+floor(const duration<_Rep, _Period>& __d)
+{
+    _ToDuration __t = duration_cast<_ToDuration>(__d);
+    if (__t > __d)
+        __t = __t - _ToDuration{1};
+    return __t;
+}
+
+template <class _ToDuration, class _Rep, class _Period>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename enable_if
+<
+    __is_duration<_ToDuration>::value,
+    _ToDuration
+>::type
+ceil(const duration<_Rep, _Period>& __d)
+{
+    _ToDuration __t = duration_cast<_ToDuration>(__d);
+    if (__t < __d)
+        __t = __t + _ToDuration{1};
+    return __t;
+}
+
+template <class _ToDuration, class _Rep, class _Period>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename enable_if
+<
+    __is_duration<_ToDuration>::value,
+    _ToDuration
+>::type
+round(const duration<_Rep, _Period>& __d)
+{
+    _ToDuration __lower = floor<_ToDuration>(__d);
+    _ToDuration __upper = __lower + _ToDuration{1};
+    auto __lowerDiff = __d - __lower;
+    auto __upperDiff = __upper - __d;
+    if (__lowerDiff < __upperDiff)
+        return __lower;
+    if (__lowerDiff > __upperDiff)
+        return __upper;
+    return __lower.count() & 1 ? __upper : __lower;
+}
+#endif
+
+// duration
+
+template <class _Rep, class _Period>
+class _LIBCPP_TEMPLATE_VIS duration
+{
+    static_assert(!__is_duration<_Rep>::value, "A duration representation can not be a duration");
+    static_assert(__is_ratio<_Period>::value, "Second template parameter of duration must be a std::ratio");
+    static_assert(_Period::num > 0, "duration period must be positive");
+
+    template <class _R1, class _R2>
+    struct __no_overflow
+    {
+    private:
+        static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
+        static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
+        static const intmax_t __n1 = _R1::num / __gcd_n1_n2;
+        static const intmax_t __d1 = _R1::den / __gcd_d1_d2;
+        static const intmax_t __n2 = _R2::num / __gcd_n1_n2;
+        static const intmax_t __d2 = _R2::den / __gcd_d1_d2;
+        static const intmax_t max = -((intmax_t(1) << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1);
+
+        template <intmax_t _Xp, intmax_t _Yp, bool __overflow>
+        struct __mul    // __overflow == false
+        {
+            static const intmax_t value = _Xp * _Yp;
+        };
+
+        template <intmax_t _Xp, intmax_t _Yp>
+        struct __mul<_Xp, _Yp, true>
+        {
+            static const intmax_t value = 1;
+        };
+
+    public:
+        static const bool value = (__n1 <= max / __d2) && (__n2 <= max / __d1);
+        typedef ratio<__mul<__n1, __d2, !value>::value,
+                      __mul<__n2, __d1, !value>::value> type;
+    };
+
+public:
+    typedef _Rep rep;
+    typedef typename _Period::type period;
+private:
+    rep __rep_;
+public:
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+#ifndef _LIBCPP_CXX03_LANG
+        duration() = default;
+#else
+        duration() {}
+#endif
+
+    template <class _Rep2>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+        explicit duration(const _Rep2& __r,
+            typename enable_if
+            <
+               is_convertible<_Rep2, rep>::value &&
+               (treat_as_floating_point<rep>::value ||
+               !treat_as_floating_point<_Rep2>::value)
+            >::type* = nullptr)
+                : __rep_(__r) {}
+
+    // conversions
+    template <class _Rep2, class _Period2>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+        duration(const duration<_Rep2, _Period2>& __d,
+            typename enable_if
+            <
+                __no_overflow<_Period2, period>::value && (
+                treat_as_floating_point<rep>::value ||
+                (__no_overflow<_Period2, period>::type::den == 1 &&
+                 !treat_as_floating_point<_Rep2>::value))
+            >::type* = nullptr)
+                : __rep_(chrono::duration_cast<duration>(__d).count()) {}
+
+    // observer
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR rep count() const {return __rep_;}
+
+    // arithmetic
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR typename common_type<duration>::type operator+() const {return typename common_type<duration>::type(*this);}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR typename common_type<duration>::type operator-() const {return typename common_type<duration>::type(-__rep_);}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 duration& operator++()      {++__rep_; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 duration  operator++(int)   {return duration(__rep_++);}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 duration& operator--()      {--__rep_; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 duration  operator--(int)   {return duration(__rep_--);}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 duration& operator+=(const duration& __d) {__rep_ += __d.count(); return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 duration& operator-=(const duration& __d) {__rep_ -= __d.count(); return *this;}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 duration& operator*=(const rep& rhs) {__rep_ *= rhs; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 duration& operator/=(const rep& rhs) {__rep_ /= rhs; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 duration& operator%=(const rep& rhs) {__rep_ %= rhs; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 duration& operator%=(const duration& rhs) {__rep_ %= rhs.count(); return *this;}
+
+    // special values
+
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR duration zero() _NOEXCEPT {return duration(duration_values<rep>::zero());}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR duration min()  _NOEXCEPT {return duration(duration_values<rep>::min());}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR duration max()  _NOEXCEPT {return duration(duration_values<rep>::max());}
+};
+
+typedef duration<long long,         nano> nanoseconds;
+typedef duration<long long,        micro> microseconds;
+typedef duration<long long,        milli> milliseconds;
+typedef duration<long long              > seconds;
+typedef duration<     long, ratio<  60> > minutes;
+typedef duration<     long, ratio<3600> > hours;
+#if _LIBCPP_STD_VER > 17
+typedef duration<     int, ratio_multiply<ratio<24>, hours::period>>         days;
+typedef duration<     int, ratio_multiply<ratio<7>,   days::period>>         weeks;
+typedef duration<     int, ratio_multiply<ratio<146097, 400>, days::period>> years;
+typedef duration<     int, ratio_divide<years::period, ratio<12>>>           months;
+#endif
+// Duration ==
+
+template <class _LhsDuration, class _RhsDuration>
+struct __duration_eq
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    bool operator()(const _LhsDuration& __lhs, const _RhsDuration& __rhs) const
+        {
+            typedef typename common_type<_LhsDuration, _RhsDuration>::type _Ct;
+            return _Ct(__lhs).count() == _Ct(__rhs).count();
+        }
+};
+
+template <class _LhsDuration>
+struct __duration_eq<_LhsDuration, _LhsDuration>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    bool operator()(const _LhsDuration& __lhs, const _LhsDuration& __rhs) const
+        {return __lhs.count() == __rhs.count();}
+};
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+bool
+operator==(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    return __duration_eq<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >()(__lhs, __rhs);
+}
+
+// Duration !=
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+bool
+operator!=(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    return !(__lhs == __rhs);
+}
+
+// Duration <
+
+template <class _LhsDuration, class _RhsDuration>
+struct __duration_lt
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    bool operator()(const _LhsDuration& __lhs, const _RhsDuration& __rhs) const
+        {
+            typedef typename common_type<_LhsDuration, _RhsDuration>::type _Ct;
+            return _Ct(__lhs).count() < _Ct(__rhs).count();
+        }
+};
+
+template <class _LhsDuration>
+struct __duration_lt<_LhsDuration, _LhsDuration>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    bool operator()(const _LhsDuration& __lhs, const _LhsDuration& __rhs) const
+        {return __lhs.count() < __rhs.count();}
+};
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+bool
+operator< (const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    return __duration_lt<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >()(__lhs, __rhs);
+}
+
+// Duration >
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+bool
+operator> (const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    return __rhs < __lhs;
+}
+
+// Duration <=
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+bool
+operator<=(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    return !(__rhs < __lhs);
+}
+
+// Duration >=
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+bool
+operator>=(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    return !(__lhs < __rhs);
+}
+
+// Duration +
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type
+operator+(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    typedef typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type _Cd;
+    return _Cd(_Cd(__lhs).count() + _Cd(__rhs).count());
+}
+
+// Duration -
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type
+operator-(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    typedef typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type _Cd;
+    return _Cd(_Cd(__lhs).count() - _Cd(__rhs).count());
+}
+
+// Duration *
+
+template <class _Rep1, class _Period, class _Rep2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename enable_if
+<
+    is_convertible<_Rep2, typename common_type<_Rep1, _Rep2>::type>::value,
+    duration<typename common_type<_Rep1, _Rep2>::type, _Period>
+>::type
+operator*(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
+{
+    typedef typename common_type<_Rep1, _Rep2>::type _Cr;
+    typedef duration<_Cr, _Period> _Cd;
+    return _Cd(_Cd(__d).count() * static_cast<_Cr>(__s));
+}
+
+template <class _Rep1, class _Period, class _Rep2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename enable_if
+<
+    is_convertible<_Rep1, typename common_type<_Rep1, _Rep2>::type>::value,
+    duration<typename common_type<_Rep1, _Rep2>::type, _Period>
+>::type
+operator*(const _Rep1& __s, const duration<_Rep2, _Period>& __d)
+{
+    return __d * __s;
+}
+
+// Duration /
+
+template <class _Rep1, class _Period, class _Rep2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename enable_if
+<
+    !__is_duration<_Rep2>::value &&
+      is_convertible<_Rep2, typename common_type<_Rep1, _Rep2>::type>::value,
+    duration<typename common_type<_Rep1, _Rep2>::type, _Period>
+>::type
+operator/(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
+{
+    typedef typename common_type<_Rep1, _Rep2>::type _Cr;
+    typedef duration<_Cr, _Period> _Cd;
+    return _Cd(_Cd(__d).count() / static_cast<_Cr>(__s));
+}
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename common_type<_Rep1, _Rep2>::type
+operator/(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    typedef typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type _Ct;
+    return _Ct(__lhs).count() / _Ct(__rhs).count();
+}
+
+// Duration %
+
+template <class _Rep1, class _Period, class _Rep2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename enable_if
+<
+    !__is_duration<_Rep2>::value &&
+      is_convertible<_Rep2, typename common_type<_Rep1, _Rep2>::type>::value,
+    duration<typename common_type<_Rep1, _Rep2>::type, _Period>
+>::type
+operator%(const duration<_Rep1, _Period>& __d, const _Rep2& __s)
+{
+    typedef typename common_type<_Rep1, _Rep2>::type _Cr;
+    typedef duration<_Cr, _Period> _Cd;
+    return _Cd(_Cd(__d).count() % static_cast<_Cr>(__s));
+}
+
+template <class _Rep1, class _Period1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type
+operator%(const duration<_Rep1, _Period1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    typedef typename common_type<_Rep1, _Rep2>::type _Cr;
+    typedef typename common_type<duration<_Rep1, _Period1>, duration<_Rep2, _Period2> >::type _Cd;
+    return _Cd(static_cast<_Cr>(_Cd(__lhs).count()) % static_cast<_Cr>(_Cd(__rhs).count()));
+}
+
+//////////////////////////////////////////////////////////
+///////////////////// time_point /////////////////////////
+//////////////////////////////////////////////////////////
+
+template <class _Clock, class _Duration = typename _Clock::duration>
+class _LIBCPP_TEMPLATE_VIS time_point
+{
+    static_assert(__is_duration<_Duration>::value,
+                  "Second template parameter of time_point must be a std::chrono::duration");
+public:
+    typedef _Clock                    clock;
+    typedef _Duration                 duration;
+    typedef typename duration::rep    rep;
+    typedef typename duration::period period;
+private:
+    duration __d_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 time_point() : __d_(duration::zero()) {}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 explicit time_point(const duration& __d) : __d_(__d) {}
+
+    // conversions
+    template <class _Duration2>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    time_point(const time_point<clock, _Duration2>& t,
+        typename enable_if
+        <
+            is_convertible<_Duration2, duration>::value
+        >::type* = nullptr)
+            : __d_(t.time_since_epoch()) {}
+
+    // observer
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 duration time_since_epoch() const {return __d_;}
+
+    // arithmetic
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 time_point& operator+=(const duration& __d) {__d_ += __d; return *this;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 time_point& operator-=(const duration& __d) {__d_ -= __d; return *this;}
+
+    // special values
+
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR time_point min() _NOEXCEPT {return time_point(duration::min());}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR time_point max() _NOEXCEPT {return time_point(duration::max());}
+};
+
+} // chrono
+
+template <class _Clock, class _Duration1, class _Duration2>
+struct _LIBCPP_TEMPLATE_VIS common_type<chrono::time_point<_Clock, _Duration1>,
+                                         chrono::time_point<_Clock, _Duration2> >
+{
+    typedef chrono::time_point<_Clock, typename common_type<_Duration1, _Duration2>::type> type;
+};
+
+namespace chrono {
+
+template <class _ToDuration, class _Clock, class _Duration>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+time_point<_Clock, _ToDuration>
+time_point_cast(const time_point<_Clock, _Duration>& __t)
+{
+    return time_point<_Clock, _ToDuration>(chrono::duration_cast<_ToDuration>(__t.time_since_epoch()));
+}
+
+#if _LIBCPP_STD_VER > 14
+template <class _ToDuration, class _Clock, class _Duration>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename enable_if
+<
+    __is_duration<_ToDuration>::value,
+    time_point<_Clock, _ToDuration>
+>::type
+floor(const time_point<_Clock, _Duration>& __t)
+{
+    return time_point<_Clock, _ToDuration>{floor<_ToDuration>(__t.time_since_epoch())};
+}
+
+template <class _ToDuration, class _Clock, class _Duration>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename enable_if
+<
+    __is_duration<_ToDuration>::value,
+    time_point<_Clock, _ToDuration>
+>::type
+ceil(const time_point<_Clock, _Duration>& __t)
+{
+    return time_point<_Clock, _ToDuration>{ceil<_ToDuration>(__t.time_since_epoch())};
+}
+
+template <class _ToDuration, class _Clock, class _Duration>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename enable_if
+<
+    __is_duration<_ToDuration>::value,
+    time_point<_Clock, _ToDuration>
+>::type
+round(const time_point<_Clock, _Duration>& __t)
+{
+    return time_point<_Clock, _ToDuration>{round<_ToDuration>(__t.time_since_epoch())};
+}
+
+template <class _Rep, class _Period>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename enable_if
+<
+    numeric_limits<_Rep>::is_signed,
+    duration<_Rep, _Period>
+>::type
+abs(duration<_Rep, _Period> __d)
+{
+    return __d >= __d.zero() ? +__d : -__d;
+}
+#endif
+
+// time_point ==
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator==(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return __lhs.time_since_epoch() == __rhs.time_since_epoch();
+}
+
+// time_point !=
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator!=(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return !(__lhs == __rhs);
+}
+
+// time_point <
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator<(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return __lhs.time_since_epoch() < __rhs.time_since_epoch();
+}
+
+// time_point >
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator>(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return __rhs < __lhs;
+}
+
+// time_point <=
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator<=(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return !(__rhs < __lhs);
+}
+
+// time_point >=
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator>=(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return !(__lhs < __rhs);
+}
+
+// time_point operator+(time_point x, duration y);
+
+template <class _Clock, class _Duration1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+time_point<_Clock, typename common_type<_Duration1, duration<_Rep2, _Period2> >::type>
+operator+(const time_point<_Clock, _Duration1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    typedef time_point<_Clock, typename common_type<_Duration1, duration<_Rep2, _Period2> >::type> _Tr;
+    return _Tr (__lhs.time_since_epoch() + __rhs);
+}
+
+// time_point operator+(duration x, time_point y);
+
+template <class _Rep1, class _Period1, class _Clock, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+time_point<_Clock, typename common_type<duration<_Rep1, _Period1>, _Duration2>::type>
+operator+(const duration<_Rep1, _Period1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return __rhs + __lhs;
+}
+
+// time_point operator-(time_point x, duration y);
+
+template <class _Clock, class _Duration1, class _Rep2, class _Period2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+time_point<_Clock, typename common_type<_Duration1, duration<_Rep2, _Period2> >::type>
+operator-(const time_point<_Clock, _Duration1>& __lhs, const duration<_Rep2, _Period2>& __rhs)
+{
+    typedef time_point<_Clock, typename common_type<_Duration1, duration<_Rep2, _Period2> >::type> _Ret;
+    return _Ret(__lhs.time_since_epoch() -__rhs);
+}
+
+// duration operator-(time_point x, time_point y);
+
+template <class _Clock, class _Duration1, class _Duration2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename common_type<_Duration1, _Duration2>::type
+operator-(const time_point<_Clock, _Duration1>& __lhs, const time_point<_Clock, _Duration2>& __rhs)
+{
+    return __lhs.time_since_epoch() - __rhs.time_since_epoch();
+}
+
+//////////////////////////////////////////////////////////
+/////////////////////// clocks ///////////////////////////
+//////////////////////////////////////////////////////////
+
+class _LIBCPP_TYPE_VIS system_clock
+{
+public:
+    typedef microseconds                     duration;
+    typedef duration::rep                    rep;
+    typedef duration::period                 period;
+    typedef chrono::time_point<system_clock> time_point;
+    static _LIBCPP_CONSTEXPR_AFTER_CXX11 const bool is_steady = false;
+
+    static time_point now() _NOEXCEPT;
+    static time_t     to_time_t  (const time_point& __t) _NOEXCEPT;
+    static time_point from_time_t(time_t __t) _NOEXCEPT;
+};
+
+#ifndef _LIBCPP_HAS_NO_MONOTONIC_CLOCK
+class _LIBCPP_TYPE_VIS steady_clock
+{
+public:
+    typedef nanoseconds                                   duration;
+    typedef duration::rep                                 rep;
+    typedef duration::period                              period;
+    typedef chrono::time_point<steady_clock, duration>    time_point;
+    static _LIBCPP_CONSTEXPR_AFTER_CXX11 const bool is_steady = true;
+
+    static time_point now() _NOEXCEPT;
+};
+
+typedef steady_clock high_resolution_clock;
+#else
+typedef system_clock high_resolution_clock;
+#endif
+
+#if _LIBCPP_STD_VER > 17
+// [time.clock.file], type file_clock
+using file_clock = _VSTD_FS::_FilesystemClock;
+
+template<class _Duration>
+using file_time = time_point<file_clock, _Duration>;
+
+
+template <class _Duration>
+using sys_time    = time_point<system_clock, _Duration>;
+using sys_seconds = sys_time<seconds>;
+using sys_days    = sys_time<days>;
+
+struct local_t {};
+template<class Duration>
+using local_time  = time_point<local_t, Duration>;
+using local_seconds = local_time<seconds>;
+using local_days    = local_time<days>;
+
+
+struct last_spec { explicit last_spec() = default; };
+
+class day {
+private:
+    unsigned char __d;
+public:
+    day() = default;
+    explicit inline constexpr day(unsigned __val) noexcept : __d(static_cast<unsigned char>(__val)) {}
+    inline constexpr day& operator++()    noexcept { ++__d; return *this; }
+    inline constexpr day  operator++(int) noexcept { day __tmp = *this; ++(*this); return __tmp; }
+    inline constexpr day& operator--()    noexcept { --__d; return *this; }
+    inline constexpr day  operator--(int) noexcept { day __tmp = *this; --(*this); return __tmp; }
+           constexpr day& operator+=(const days& __dd) noexcept;
+           constexpr day& operator-=(const days& __dd) noexcept;
+    explicit inline constexpr operator unsigned() const noexcept { return __d; }
+    inline constexpr bool ok() const noexcept { return __d >= 1 && __d <= 31; }
+  };
+
+
+inline constexpr
+bool operator==(const day& __lhs, const day& __rhs) noexcept
+{ return static_cast<unsigned>(__lhs) == static_cast<unsigned>(__rhs); }
+
+inline constexpr
+bool operator!=(const day& __lhs, const day& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+inline constexpr
+bool operator< (const day& __lhs, const day& __rhs) noexcept
+{ return static_cast<unsigned>(__lhs) <  static_cast<unsigned>(__rhs); }
+
+inline constexpr
+bool operator> (const day& __lhs, const day& __rhs) noexcept
+{ return __rhs < __lhs; }
+
+inline constexpr
+bool operator<=(const day& __lhs, const day& __rhs) noexcept
+{ return !(__rhs < __lhs);}
+
+inline constexpr
+bool operator>=(const day& __lhs, const day& __rhs) noexcept
+{ return !(__lhs < __rhs); }
+
+inline constexpr
+day operator+ (const day& __lhs, const days& __rhs) noexcept
+{ return day(static_cast<unsigned>(__lhs) + __rhs.count()); }
+
+inline constexpr
+day operator+ (const days& __lhs, const day& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+inline constexpr
+day operator- (const day& __lhs, const days& __rhs) noexcept
+{ return __lhs + -__rhs; }
+
+inline constexpr
+days operator-(const day& __lhs, const day& __rhs) noexcept
+{ return days(static_cast<int>(static_cast<unsigned>(__lhs)) -
+              static_cast<int>(static_cast<unsigned>(__rhs))); }
+
+inline constexpr day& day::operator+=(const days& __dd) noexcept
+{ *this = *this + __dd; return *this; }
+
+inline constexpr day& day::operator-=(const days& __dd) noexcept
+{ *this = *this - __dd; return *this; }
+
+
+class month {
+private:
+    unsigned char __m;
+public:
+    month() = default;
+    explicit inline constexpr month(unsigned __val) noexcept : __m(static_cast<unsigned char>(__val)) {}
+    inline constexpr month& operator++()    noexcept { ++__m; return *this; }
+    inline constexpr month  operator++(int) noexcept { month __tmp = *this; ++(*this); return __tmp; }
+    inline constexpr month& operator--()    noexcept { --__m; return *this; }
+    inline constexpr month  operator--(int) noexcept { month __tmp = *this; --(*this); return __tmp; }
+           constexpr month& operator+=(const months& __m1) noexcept;
+           constexpr month& operator-=(const months& __m1) noexcept;
+    explicit inline constexpr operator unsigned() const noexcept { return __m; }
+    inline constexpr bool ok() const noexcept { return __m >= 1 && __m <= 12; }
+};
+
+
+inline constexpr
+bool operator==(const month& __lhs, const month& __rhs) noexcept
+{ return static_cast<unsigned>(__lhs) == static_cast<unsigned>(__rhs); }
+
+inline constexpr
+bool operator!=(const month& __lhs, const month& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+inline constexpr
+bool operator< (const month& __lhs, const month& __rhs) noexcept
+{ return static_cast<unsigned>(__lhs)  < static_cast<unsigned>(__rhs); }
+
+inline constexpr
+bool operator> (const month& __lhs, const month& __rhs) noexcept
+{ return __rhs < __lhs; }
+
+inline constexpr
+bool operator<=(const month& __lhs, const month& __rhs) noexcept
+{ return !(__rhs < __lhs); }
+
+inline constexpr
+bool operator>=(const month& __lhs, const month& __rhs) noexcept
+{ return !(__lhs < __rhs); }
+
+inline constexpr
+month operator+ (const month& __lhs, const months& __rhs) noexcept
+{
+    auto const __mu = static_cast<long long>(static_cast<unsigned>(__lhs)) + (__rhs.count() - 1);
+    auto const __yr = (__mu >= 0 ? __mu : __mu - 11) / 12;
+    return month{static_cast<unsigned>(__mu - __yr * 12 + 1)};
+}
+
+inline constexpr
+month operator+ (const months& __lhs, const month& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+inline constexpr
+month operator- (const month& __lhs, const months& __rhs) noexcept
+{ return __lhs + -__rhs; }
+
+inline constexpr
+months operator-(const month& __lhs, const month& __rhs) noexcept
+{
+    auto const __dm = static_cast<unsigned>(__lhs) - static_cast<unsigned>(__rhs);
+    return months(__dm <= 11 ? __dm : __dm + 12);
+}
+
+inline constexpr month& month::operator+=(const months& __dm) noexcept
+{ *this = *this + __dm; return *this; }
+
+inline constexpr month& month::operator-=(const months& __dm) noexcept
+{ *this = *this - __dm; return *this; }
+
+
+class year {
+private:
+    short __y;
+public:
+    year() = default;
+    explicit inline constexpr year(int __val) noexcept : __y(static_cast<short>(__val)) {}
+
+    inline constexpr year& operator++()    noexcept { ++__y; return *this; }
+    inline constexpr year  operator++(int) noexcept { year __tmp = *this; ++(*this); return __tmp; }
+    inline constexpr year& operator--()    noexcept { --__y; return *this; }
+    inline constexpr year  operator--(int) noexcept { year __tmp = *this; --(*this); return __tmp; }
+           constexpr year& operator+=(const years& __dy) noexcept;
+           constexpr year& operator-=(const years& __dy) noexcept;
+    inline constexpr year operator+() const noexcept { return *this; }
+    inline constexpr year operator-() const noexcept { return year{-__y}; }
+
+    inline constexpr bool is_leap() const noexcept { return __y % 4 == 0 && (__y % 100 != 0 || __y % 400 == 0); }
+    explicit inline constexpr operator int() const noexcept { return __y; }
+           constexpr bool ok() const noexcept;
+    static inline constexpr year min() noexcept { return year{-32767}; }
+    static inline constexpr year max() noexcept { return year{ 32767}; }
+};
+
+
+inline constexpr
+bool operator==(const year& __lhs, const year& __rhs) noexcept
+{ return static_cast<int>(__lhs) == static_cast<int>(__rhs); }
+
+inline constexpr
+bool operator!=(const year& __lhs, const year& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+inline constexpr
+bool operator< (const year& __lhs, const year& __rhs) noexcept
+{ return static_cast<int>(__lhs)  < static_cast<int>(__rhs); }
+
+inline constexpr
+bool operator> (const year& __lhs, const year& __rhs) noexcept
+{ return __rhs < __lhs; }
+
+inline constexpr
+bool operator<=(const year& __lhs, const year& __rhs) noexcept
+{ return !(__rhs < __lhs); }
+
+inline constexpr
+bool operator>=(const year& __lhs, const year& __rhs) noexcept
+{ return !(__lhs < __rhs); }
+
+inline constexpr
+year operator+ (const year& __lhs, const years& __rhs) noexcept
+{ return year(static_cast<int>(__lhs) + __rhs.count()); }
+
+inline constexpr
+year operator+ (const years& __lhs, const year& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+inline constexpr
+year operator- (const year& __lhs, const years& __rhs) noexcept
+{ return __lhs + -__rhs; }
+
+inline constexpr
+years operator-(const year& __lhs, const year& __rhs) noexcept
+{ return years{static_cast<int>(__lhs) - static_cast<int>(__rhs)}; }
+
+
+inline constexpr year& year::operator+=(const years& __dy) noexcept
+{ *this = *this + __dy; return *this; }
+
+inline constexpr year& year::operator-=(const years& __dy) noexcept
+{ *this = *this - __dy; return *this; }
+
+inline constexpr bool year::ok() const noexcept
+{ return static_cast<int>(min()) <= __y && __y <= static_cast<int>(max()); }
+
+class weekday_indexed;
+class weekday_last;
+
+class weekday {
+private:
+    unsigned char __wd;
+public:
+  weekday() = default;
+  inline explicit constexpr weekday(unsigned __val) noexcept : __wd(static_cast<unsigned char>(__val == 7 ? 0 : __val)) {}
+  inline constexpr          weekday(const sys_days& __sysd) noexcept
+          : __wd(__weekday_from_days(__sysd.time_since_epoch().count())) {}
+  inline explicit constexpr weekday(const local_days& __locd) noexcept
+          : __wd(__weekday_from_days(__locd.time_since_epoch().count())) {}
+
+  inline constexpr weekday& operator++()    noexcept { __wd = (__wd == 6 ? 0 : __wd + 1); return *this; }
+  inline constexpr weekday  operator++(int) noexcept { weekday __tmp = *this; ++(*this); return __tmp; }
+  inline constexpr weekday& operator--()    noexcept { __wd = (__wd == 0 ? 6 : __wd - 1); return *this; }
+  inline constexpr weekday  operator--(int) noexcept { weekday __tmp = *this; --(*this); return __tmp; }
+         constexpr weekday& operator+=(const days& __dd) noexcept;
+         constexpr weekday& operator-=(const days& __dd) noexcept;
+  inline constexpr unsigned c_encoding()   const noexcept { return __wd; }
+  inline constexpr unsigned iso_encoding() const noexcept { return __wd == 0u ? 7 : __wd; }
+  inline constexpr bool ok() const noexcept { return __wd <= 6; }
+         constexpr weekday_indexed operator[](unsigned __index) const noexcept;
+         constexpr weekday_last    operator[](last_spec) const noexcept;
+
+  // TODO: Make private?
+  static constexpr unsigned char __weekday_from_days(int __days) noexcept;
+};
+
+
+// https://howardhinnant.github.io/date_algorithms.html#weekday_from_days
+inline constexpr
+unsigned char weekday::__weekday_from_days(int __days) noexcept
+{
+    return static_cast<unsigned char>(
+              static_cast<unsigned>(__days >= -4 ? (__days+4) % 7 : (__days+5) % 7 + 6)
+           );
+}
+
+inline constexpr
+bool operator==(const weekday& __lhs, const weekday& __rhs) noexcept
+{ return __lhs.c_encoding() == __rhs.c_encoding(); }
+
+inline constexpr
+bool operator!=(const weekday& __lhs, const weekday& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+inline constexpr
+bool operator< (const weekday& __lhs, const weekday& __rhs) noexcept
+{ return __lhs.c_encoding() < __rhs.c_encoding(); }
+
+inline constexpr
+bool operator> (const weekday& __lhs, const weekday& __rhs) noexcept
+{ return __rhs < __lhs; }
+
+inline constexpr
+bool operator<=(const weekday& __lhs, const weekday& __rhs) noexcept
+{ return !(__rhs < __lhs);}
+
+inline constexpr
+bool operator>=(const weekday& __lhs, const weekday& __rhs) noexcept
+{ return !(__lhs < __rhs); }
+
+constexpr weekday operator+(const weekday& __lhs, const days& __rhs) noexcept
+{
+    auto const __mu = static_cast<long long>(__lhs.c_encoding()) + __rhs.count();
+    auto const __yr = (__mu >= 0 ? __mu : __mu - 6) / 7;
+    return weekday{static_cast<unsigned>(__mu - __yr * 7)};
+}
+
+constexpr weekday operator+(const days& __lhs, const weekday& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+constexpr weekday operator-(const weekday& __lhs, const days& __rhs) noexcept
+{ return __lhs + -__rhs; }
+
+constexpr days operator-(const weekday& __lhs, const weekday& __rhs) noexcept
+{
+    const int __wdu = __lhs.c_encoding() - __rhs.c_encoding();
+    const int __wk = (__wdu >= 0 ? __wdu : __wdu-6) / 7;
+    return days{__wdu - __wk * 7};
+}
+
+inline constexpr weekday& weekday::operator+=(const days& __dd) noexcept
+{ *this = *this + __dd; return *this; }
+
+inline constexpr weekday& weekday::operator-=(const days& __dd) noexcept
+{ *this = *this - __dd; return *this; }
+
+
+class weekday_indexed {
+private:
+    chrono::weekday __wd;
+    unsigned char          __idx;
+public:
+    weekday_indexed() = default;
+    inline constexpr weekday_indexed(const chrono::weekday& __wdval, unsigned __idxval) noexcept
+        : __wd{__wdval}, __idx(__idxval) {}
+    inline constexpr chrono::weekday weekday() const noexcept { return __wd; }
+    inline constexpr unsigned                 index() const noexcept { return __idx; }
+    inline constexpr bool ok() const noexcept { return __wd.ok() && __idx >= 1 && __idx <= 5; }
+};
+
+inline constexpr
+bool operator==(const weekday_indexed& __lhs, const weekday_indexed& __rhs) noexcept
+{ return __lhs.weekday() == __rhs.weekday() && __lhs.index() == __rhs.index(); }
+
+inline constexpr
+bool operator!=(const weekday_indexed& __lhs, const weekday_indexed& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+
+class weekday_last {
+private:
+    chrono::weekday __wd;
+public:
+    explicit constexpr weekday_last(const chrono::weekday& __val) noexcept
+        : __wd{__val} {}
+    constexpr chrono::weekday weekday() const noexcept { return __wd; }
+    constexpr bool ok() const noexcept { return __wd.ok(); }
+};
+
+inline constexpr
+bool operator==(const weekday_last& __lhs, const weekday_last& __rhs) noexcept
+{ return __lhs.weekday() == __rhs.weekday(); }
+
+inline constexpr
+bool operator!=(const weekday_last& __lhs, const weekday_last& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+inline constexpr
+weekday_indexed weekday::operator[](unsigned __index) const noexcept { return weekday_indexed{*this, __index}; }
+
+inline constexpr
+weekday_last    weekday::operator[](last_spec) const noexcept { return weekday_last{*this}; }
+
+
+inline constexpr last_spec last{};
+inline constexpr weekday   Sunday{0};
+inline constexpr weekday   Monday{1};
+inline constexpr weekday   Tuesday{2};
+inline constexpr weekday   Wednesday{3};
+inline constexpr weekday   Thursday{4};
+inline constexpr weekday   Friday{5};
+inline constexpr weekday   Saturday{6};
+
+inline constexpr month January{1};
+inline constexpr month February{2};
+inline constexpr month March{3};
+inline constexpr month April{4};
+inline constexpr month May{5};
+inline constexpr month June{6};
+inline constexpr month July{7};
+inline constexpr month August{8};
+inline constexpr month September{9};
+inline constexpr month October{10};
+inline constexpr month November{11};
+inline constexpr month December{12};
+
+
+class month_day {
+private:
+   chrono::month __m;
+   chrono::day   __d;
+public:
+    month_day() = default;
+    constexpr month_day(const chrono::month& __mval, const chrono::day& __dval) noexcept
+        : __m{__mval}, __d{__dval} {}
+    inline constexpr chrono::month month() const noexcept { return __m; }
+    inline constexpr chrono::day   day()   const noexcept { return __d; }
+    constexpr bool ok() const noexcept;
+};
+
+inline constexpr
+bool month_day::ok() const noexcept
+{
+    if (!__m.ok()) return false;
+    const unsigned __dval = static_cast<unsigned>(__d);
+    if (__dval < 1 || __dval > 31) return false;
+    if (__dval <= 29) return true;
+//  Now we've got either 30 or 31
+    const unsigned __mval = static_cast<unsigned>(__m);
+    if (__mval == 2) return false;
+    if (__mval == 4 || __mval == 6 || __mval == 9 || __mval == 11)
+        return __dval == 30;
+    return true;
+}
+
+inline constexpr
+bool operator==(const month_day& __lhs, const month_day& __rhs) noexcept
+{ return __lhs.month() == __rhs.month() && __lhs.day() == __rhs.day(); }
+
+inline constexpr
+bool operator!=(const month_day& __lhs, const month_day& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+inline constexpr
+month_day operator/(const month& __lhs, const day& __rhs) noexcept
+{ return month_day{__lhs, __rhs}; }
+
+constexpr
+month_day operator/(const day& __lhs, const month& __rhs) noexcept
+{ return __rhs / __lhs; }
+
+inline constexpr
+month_day operator/(const month& __lhs, int __rhs) noexcept
+{ return __lhs / day(__rhs); }
+
+constexpr
+month_day operator/(int __lhs, const day& __rhs) noexcept
+{ return month(__lhs) / __rhs; }
+
+constexpr
+month_day operator/(const day& __lhs, int __rhs) noexcept
+{ return month(__rhs) / __lhs; }
+
+
+inline constexpr
+bool operator< (const month_day& __lhs, const month_day& __rhs) noexcept
+{ return __lhs.month() != __rhs.month() ? __lhs.month() < __rhs.month() : __lhs.day() < __rhs.day(); }
+
+inline constexpr
+bool operator> (const month_day& __lhs, const month_day& __rhs) noexcept
+{ return __rhs < __lhs; }
+
+inline constexpr
+bool operator<=(const month_day& __lhs, const month_day& __rhs) noexcept
+{ return !(__rhs < __lhs);}
+
+inline constexpr
+bool operator>=(const month_day& __lhs, const month_day& __rhs) noexcept
+{ return !(__lhs < __rhs); }
+
+
+
+class month_day_last {
+private:
+    chrono::month __m;
+public:
+    explicit constexpr month_day_last(const chrono::month& __val) noexcept
+        : __m{__val} {}
+    inline constexpr chrono::month month() const noexcept { return __m; }
+    inline constexpr bool ok() const noexcept { return __m.ok(); }
+};
+
+inline constexpr
+bool operator==(const month_day_last& __lhs, const month_day_last& __rhs) noexcept
+{ return __lhs.month() == __rhs.month(); }
+
+inline constexpr
+bool operator!=(const month_day_last& __lhs, const month_day_last& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+inline constexpr
+bool operator< (const month_day_last& __lhs, const month_day_last& __rhs) noexcept
+{ return __lhs.month() < __rhs.month(); }
+
+inline constexpr
+bool operator> (const month_day_last& __lhs, const month_day_last& __rhs) noexcept
+{ return __rhs < __lhs; }
+
+inline constexpr
+bool operator<=(const month_day_last& __lhs, const month_day_last& __rhs) noexcept
+{ return !(__rhs < __lhs);}
+
+inline constexpr
+bool operator>=(const month_day_last& __lhs, const month_day_last& __rhs) noexcept
+{ return !(__lhs < __rhs); }
+
+inline constexpr
+month_day_last operator/(const month& __lhs, last_spec) noexcept
+{ return month_day_last{__lhs}; }
+
+inline constexpr
+month_day_last operator/(last_spec, const month& __rhs) noexcept
+{ return month_day_last{__rhs}; }
+
+inline constexpr
+month_day_last operator/(int __lhs, last_spec) noexcept
+{ return month_day_last{month(__lhs)}; }
+
+inline constexpr
+month_day_last operator/(last_spec, int __rhs) noexcept
+{ return month_day_last{month(__rhs)}; }
+
+
+class month_weekday {
+private:
+    chrono::month __m;
+    chrono::weekday_indexed __wdi;
+public:
+    month_weekday() = default;
+    constexpr month_weekday(const chrono::month& __mval, const chrono::weekday_indexed& __wdival) noexcept
+        : __m{__mval}, __wdi{__wdival} {}
+    inline constexpr chrono::month                     month() const noexcept { return __m; }
+    inline constexpr chrono::weekday_indexed weekday_indexed() const noexcept { return __wdi; }
+    inline constexpr bool                                 ok() const noexcept { return __m.ok() && __wdi.ok(); }
+};
+
+inline constexpr
+bool operator==(const month_weekday& __lhs, const month_weekday& __rhs) noexcept
+{ return __lhs.month() == __rhs.month() && __lhs.weekday_indexed() == __rhs.weekday_indexed(); }
+
+inline constexpr
+bool operator!=(const month_weekday& __lhs, const month_weekday& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+inline constexpr
+month_weekday operator/(const month& __lhs, const weekday_indexed& __rhs) noexcept
+{ return month_weekday{__lhs, __rhs}; }
+
+inline constexpr
+month_weekday operator/(int __lhs, const weekday_indexed& __rhs) noexcept
+{ return month_weekday{month(__lhs), __rhs}; }
+
+inline constexpr
+month_weekday operator/(const weekday_indexed& __lhs, const month& __rhs) noexcept
+{ return month_weekday{__rhs, __lhs}; }
+
+inline constexpr
+month_weekday operator/(const weekday_indexed& __lhs, int __rhs) noexcept
+{ return month_weekday{month(__rhs), __lhs}; }
+
+
+class month_weekday_last {
+    chrono::month        __m;
+    chrono::weekday_last __wdl;
+  public:
+    constexpr month_weekday_last(const chrono::month& __mval, const chrono::weekday_last& __wdlval) noexcept
+        : __m{__mval}, __wdl{__wdlval} {}
+    inline constexpr chrono::month               month() const noexcept { return __m; }
+    inline constexpr chrono::weekday_last weekday_last() const noexcept { return __wdl; }
+    inline constexpr bool                           ok() const noexcept { return __m.ok() && __wdl.ok(); }
+};
+
+inline constexpr
+bool operator==(const month_weekday_last& __lhs, const month_weekday_last& __rhs) noexcept
+{ return __lhs.month() == __rhs.month() && __lhs.weekday_last() == __rhs.weekday_last(); }
+
+inline constexpr
+bool operator!=(const month_weekday_last& __lhs, const month_weekday_last& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+
+inline constexpr
+month_weekday_last operator/(const month& __lhs, const weekday_last& __rhs) noexcept
+{ return month_weekday_last{__lhs, __rhs}; }
+
+inline constexpr
+month_weekday_last operator/(int __lhs, const weekday_last& __rhs) noexcept
+{ return month_weekday_last{month(__lhs), __rhs}; }
+
+inline constexpr
+month_weekday_last operator/(const weekday_last& __lhs, const month& __rhs) noexcept
+{ return month_weekday_last{__rhs, __lhs}; }
+
+inline constexpr
+month_weekday_last operator/(const weekday_last& __lhs, int __rhs) noexcept
+{ return month_weekday_last{month(__rhs), __lhs}; }
+
+
+class year_month {
+    chrono::year  __y;
+    chrono::month __m;
+public:
+    year_month() = default;
+    constexpr year_month(const chrono::year& __yval, const chrono::month& __mval) noexcept
+        : __y{__yval}, __m{__mval} {}
+    inline constexpr chrono::year  year()  const noexcept { return __y; }
+    inline constexpr chrono::month month() const noexcept { return __m; }
+    inline constexpr year_month& operator+=(const months& __dm) noexcept { this->__m += __dm; return *this; }
+    inline constexpr year_month& operator-=(const months& __dm) noexcept { this->__m -= __dm; return *this; }
+    inline constexpr year_month& operator+=(const years& __dy)  noexcept { this->__y += __dy; return *this; }
+    inline constexpr year_month& operator-=(const years& __dy)  noexcept { this->__y -= __dy; return *this; }
+    inline constexpr bool ok() const noexcept { return __y.ok() && __m.ok(); }
+};
+
+inline constexpr
+year_month operator/(const year& __y, const month& __m) noexcept { return year_month{__y, __m}; }
+
+inline constexpr
+year_month operator/(const year& __y, int __m) noexcept { return year_month{__y, month(__m)}; }
+
+inline constexpr
+bool operator==(const year_month& __lhs, const year_month& __rhs) noexcept
+{ return __lhs.year() == __rhs.year() && __lhs.month() == __rhs.month(); }
+
+inline constexpr
+bool operator!=(const year_month& __lhs, const year_month& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+inline constexpr
+bool operator< (const year_month& __lhs, const year_month& __rhs) noexcept
+{ return __lhs.year() != __rhs.year() ? __lhs.year() < __rhs.year() : __lhs.month() < __rhs.month(); }
+
+inline constexpr
+bool operator> (const year_month& __lhs, const year_month& __rhs) noexcept
+{ return __rhs < __lhs; }
+
+inline constexpr
+bool operator<=(const year_month& __lhs, const year_month& __rhs) noexcept
+{ return !(__rhs < __lhs);}
+
+inline constexpr
+bool operator>=(const year_month& __lhs, const year_month& __rhs) noexcept
+{ return !(__lhs < __rhs); }
+
+constexpr year_month operator+(const year_month& __lhs, const months& __rhs) noexcept
+{
+    int __dmi = static_cast<int>(static_cast<unsigned>(__lhs.month())) - 1 + __rhs.count();
+    const int __dy = (__dmi >= 0 ? __dmi : __dmi-11) / 12;
+    __dmi = __dmi - __dy * 12 + 1;
+    return (__lhs.year() + years(__dy)) / month(static_cast<unsigned>(__dmi));
+}
+
+constexpr year_month operator+(const months& __lhs, const year_month& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+constexpr year_month operator+(const year_month& __lhs, const years& __rhs) noexcept
+{ return (__lhs.year() + __rhs) / __lhs.month(); }
+
+constexpr year_month operator+(const years& __lhs, const year_month& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+constexpr months     operator-(const year_month& __lhs, const year_month& __rhs) noexcept
+{ return (__lhs.year() - __rhs.year()) + months(static_cast<unsigned>(__lhs.month()) - static_cast<unsigned>(__rhs.month())); }
+
+constexpr year_month operator-(const year_month& __lhs, const months& __rhs) noexcept
+{ return __lhs + -__rhs; }
+
+constexpr year_month operator-(const year_month& __lhs, const years& __rhs) noexcept
+{ return __lhs + -__rhs; }
+
+class year_month_day_last;
+
+class year_month_day {
+private:
+    chrono::year  __y;
+    chrono::month __m;
+    chrono::day   __d;
+public:
+     year_month_day() = default;
+     inline constexpr year_month_day(
+            const chrono::year& __yval, const chrono::month& __mval, const chrono::day& __dval) noexcept
+            : __y{__yval}, __m{__mval}, __d{__dval} {}
+            constexpr year_month_day(const year_month_day_last& __ymdl) noexcept;
+     inline constexpr year_month_day(const sys_days& __sysd) noexcept
+            : year_month_day(__from_days(__sysd.time_since_epoch())) {}
+     inline explicit constexpr year_month_day(const local_days& __locd) noexcept
+            : year_month_day(__from_days(__locd.time_since_epoch())) {}
+
+            constexpr year_month_day& operator+=(const months& __dm) noexcept;
+            constexpr year_month_day& operator-=(const months& __dm) noexcept;
+            constexpr year_month_day& operator+=(const years& __dy)  noexcept;
+            constexpr year_month_day& operator-=(const years& __dy)  noexcept;
+
+     inline constexpr chrono::year   year() const noexcept { return __y; }
+     inline constexpr chrono::month month() const noexcept { return __m; }
+     inline constexpr chrono::day     day() const noexcept { return __d; }
+     inline constexpr operator   sys_days() const noexcept          { return   sys_days{__to_days()}; }
+     inline explicit constexpr operator local_days() const noexcept { return local_days{__to_days()}; }
+
+            constexpr bool             ok() const noexcept;
+
+     static constexpr year_month_day __from_days(days __d) noexcept;
+     constexpr days __to_days() const noexcept;
+};
+
+
+// https://howardhinnant.github.io/date_algorithms.html#civil_from_days
+inline constexpr
+year_month_day
+year_month_day::__from_days(days __d) noexcept
+{
+    static_assert(numeric_limits<unsigned>::digits >= 18, "");
+    static_assert(numeric_limits<int>::digits >= 20     , "");
+    const int      __z = __d.count() + 719468;
+    const int      __era = (__z >= 0 ? __z : __z - 146096) / 146097;
+    const unsigned __doe = static_cast<unsigned>(__z - __era * 146097);              // [0, 146096]
+    const unsigned __yoe = (__doe - __doe/1460 + __doe/36524 - __doe/146096) / 365;  // [0, 399]
+    const int      __yr = static_cast<int>(__yoe) + __era * 400;
+    const unsigned __doy = __doe - (365 * __yoe + __yoe/4 - __yoe/100);              // [0, 365]
+    const unsigned __mp = (5 * __doy + 2)/153;                                       // [0, 11]
+    const unsigned __dy = __doy - (153 * __mp + 2)/5 + 1;                            // [1, 31]
+    const unsigned __mth = __mp + (__mp < 10 ? 3 : -9);                              // [1, 12]
+    return year_month_day{chrono::year{__yr + (__mth <= 2)}, chrono::month{__mth}, chrono::day{__dy}};
+}
+
+// https://howardhinnant.github.io/date_algorithms.html#days_from_civil
+inline constexpr days year_month_day::__to_days() const noexcept
+{
+    static_assert(numeric_limits<unsigned>::digits >= 18, "");
+    static_assert(numeric_limits<int>::digits >= 20     , "");
+
+    const int      __yr  = static_cast<int>(__y) - (__m <= February);
+    const unsigned __mth = static_cast<unsigned>(__m);
+    const unsigned __dy  = static_cast<unsigned>(__d);
+
+    const int      __era = (__yr >= 0 ? __yr : __yr - 399) / 400;
+    const unsigned __yoe = static_cast<unsigned>(__yr - __era * 400);                // [0, 399]
+    const unsigned __doy = (153 * (__mth + (__mth > 2 ? -3 : 9)) + 2) / 5 + __dy-1;  // [0, 365]
+    const unsigned __doe = __yoe * 365 + __yoe/4 - __yoe/100 + __doy;                // [0, 146096]
+    return days{__era * 146097 + static_cast<int>(__doe) - 719468};
+}
+
+inline constexpr
+bool operator==(const year_month_day& __lhs, const year_month_day& __rhs) noexcept
+{ return __lhs.year() == __rhs.year() && __lhs.month() == __rhs.month() && __lhs.day() == __rhs.day(); }
+
+inline constexpr
+bool operator!=(const year_month_day& __lhs, const year_month_day& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+inline constexpr
+bool operator< (const year_month_day& __lhs, const year_month_day& __rhs) noexcept
+{
+    if (__lhs.year() < __rhs.year()) return true;
+    if (__lhs.year() > __rhs.year()) return false;
+    if (__lhs.month() < __rhs.month()) return true;
+    if (__lhs.month() > __rhs.month()) return false;
+    return __lhs.day() < __rhs.day();
+}
+
+inline constexpr
+bool operator> (const year_month_day& __lhs, const year_month_day& __rhs) noexcept
+{ return __rhs < __lhs; }
+
+inline constexpr
+bool operator<=(const year_month_day& __lhs, const year_month_day& __rhs) noexcept
+{ return !(__rhs < __lhs);}
+
+inline constexpr
+bool operator>=(const year_month_day& __lhs, const year_month_day& __rhs) noexcept
+{ return !(__lhs < __rhs); }
+
+inline constexpr
+year_month_day operator/(const year_month& __lhs, const day& __rhs) noexcept
+{ return year_month_day{__lhs.year(), __lhs.month(), __rhs}; }
+
+inline constexpr
+year_month_day operator/(const year_month& __lhs, int __rhs) noexcept
+{ return __lhs / day(__rhs); }
+
+inline constexpr
+year_month_day operator/(const year& __lhs, const month_day& __rhs) noexcept
+{ return __lhs / __rhs.month() / __rhs.day(); }
+
+inline constexpr
+year_month_day operator/(int __lhs, const month_day& __rhs) noexcept
+{ return year(__lhs) / __rhs; }
+
+inline constexpr
+year_month_day operator/(const month_day& __lhs, const year& __rhs) noexcept
+{ return __rhs / __lhs; }
+
+inline constexpr
+year_month_day operator/(const month_day& __lhs, int __rhs) noexcept
+{ return year(__rhs) / __lhs; }
+
+
+inline constexpr
+year_month_day operator+(const year_month_day& __lhs, const months& __rhs) noexcept
+{ return (__lhs.year()/__lhs.month() + __rhs)/__lhs.day(); }
+
+inline constexpr
+year_month_day operator+(const months& __lhs, const year_month_day& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+inline constexpr
+year_month_day operator-(const year_month_day& __lhs, const months& __rhs) noexcept
+{ return __lhs + -__rhs; }
+
+inline constexpr
+year_month_day operator+(const year_month_day& __lhs, const years& __rhs) noexcept
+{ return (__lhs.year() + __rhs) / __lhs.month() / __lhs.day(); }
+
+inline constexpr
+year_month_day operator+(const years& __lhs, const year_month_day& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+inline constexpr
+year_month_day operator-(const year_month_day& __lhs, const years& __rhs) noexcept
+{ return __lhs + -__rhs; }
+
+inline constexpr year_month_day& year_month_day::operator+=(const months& __dm) noexcept { *this = *this + __dm; return *this; }
+inline constexpr year_month_day& year_month_day::operator-=(const months& __dm) noexcept { *this = *this - __dm; return *this; }
+inline constexpr year_month_day& year_month_day::operator+=(const years& __dy)  noexcept { *this = *this + __dy; return *this; }
+inline constexpr year_month_day& year_month_day::operator-=(const years& __dy)  noexcept { *this = *this - __dy; return *this; }
+
+class year_month_day_last {
+private:
+    chrono::year           __y;
+    chrono::month_day_last __mdl;
+public:
+     constexpr year_month_day_last(const year& __yval, const month_day_last& __mdlval) noexcept
+        : __y{__yval}, __mdl{__mdlval} {}
+
+     constexpr year_month_day_last& operator+=(const months& __m) noexcept;
+     constexpr year_month_day_last& operator-=(const months& __m) noexcept;
+     constexpr year_month_day_last& operator+=(const years& __y)  noexcept;
+     constexpr year_month_day_last& operator-=(const years& __y)  noexcept;
+
+     inline constexpr chrono::year                     year() const noexcept { return __y; }
+     inline constexpr chrono::month                   month() const noexcept { return __mdl.month(); }
+     inline constexpr chrono::month_day_last month_day_last() const noexcept { return __mdl; }
+            constexpr chrono::day                       day() const noexcept;
+     inline constexpr operator                     sys_days() const noexcept { return   sys_days{year()/month()/day()}; }
+     inline explicit constexpr operator          local_days() const noexcept { return local_days{year()/month()/day()}; }
+     inline constexpr bool                               ok() const noexcept { return __y.ok() && __mdl.ok(); }
+};
+
+inline constexpr
+chrono::day year_month_day_last::day() const noexcept
+{
+    constexpr chrono::day __d[] =
+    {
+        chrono::day(31), chrono::day(28), chrono::day(31),
+        chrono::day(30), chrono::day(31), chrono::day(30),
+        chrono::day(31), chrono::day(31), chrono::day(30),
+        chrono::day(31), chrono::day(30), chrono::day(31)
+    };
+    return (month() != February || !__y.is_leap()) && month().ok() ?
+        __d[static_cast<unsigned>(month()) - 1] : chrono::day{29};
+}
+
+inline constexpr
+bool operator==(const year_month_day_last& __lhs, const year_month_day_last& __rhs) noexcept
+{ return __lhs.year() == __rhs.year() && __lhs.month_day_last() == __rhs.month_day_last(); }
+
+inline constexpr
+bool operator!=(const year_month_day_last& __lhs, const year_month_day_last& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+inline constexpr
+bool operator< (const year_month_day_last& __lhs, const year_month_day_last& __rhs) noexcept
+{
+    if (__lhs.year() < __rhs.year()) return true;
+    if (__lhs.year() > __rhs.year()) return false;
+    return __lhs.month_day_last() < __rhs.month_day_last();
+}
+
+inline constexpr
+bool operator> (const year_month_day_last& __lhs, const year_month_day_last& __rhs) noexcept
+{ return __rhs < __lhs; }
+
+inline constexpr
+bool operator<=(const year_month_day_last& __lhs, const year_month_day_last& __rhs) noexcept
+{ return !(__rhs < __lhs);}
+
+inline constexpr
+bool operator>=(const year_month_day_last& __lhs, const year_month_day_last& __rhs) noexcept
+{ return !(__lhs < __rhs); }
+
+inline constexpr year_month_day_last operator/(const year_month& __lhs, last_spec) noexcept
+{ return year_month_day_last{__lhs.year(), month_day_last{__lhs.month()}}; }
+
+inline constexpr year_month_day_last operator/(const year& __lhs, const month_day_last& __rhs) noexcept
+{ return year_month_day_last{__lhs, __rhs}; }
+
+inline constexpr year_month_day_last operator/(int __lhs, const month_day_last& __rhs) noexcept
+{ return year_month_day_last{year{__lhs}, __rhs}; }
+
+inline constexpr year_month_day_last operator/(const month_day_last& __lhs, const year& __rhs) noexcept
+{ return __rhs / __lhs; }
+
+inline constexpr year_month_day_last operator/(const month_day_last& __lhs, int __rhs) noexcept
+{ return year{__rhs} / __lhs; }
+
+
+inline constexpr
+year_month_day_last operator+(const year_month_day_last& __lhs, const months& __rhs) noexcept
+{ return (__lhs.year() / __lhs.month() + __rhs) / last; }
+
+inline constexpr
+year_month_day_last operator+(const months& __lhs, const year_month_day_last& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+inline constexpr
+year_month_day_last operator-(const year_month_day_last& __lhs, const months& __rhs) noexcept
+{ return __lhs + (-__rhs); }
+
+inline constexpr
+year_month_day_last operator+(const year_month_day_last& __lhs, const years& __rhs) noexcept
+{ return year_month_day_last{__lhs.year() + __rhs, __lhs.month_day_last()}; }
+
+inline constexpr
+year_month_day_last operator+(const years& __lhs, const year_month_day_last& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+inline constexpr
+year_month_day_last operator-(const year_month_day_last& __lhs, const years& __rhs) noexcept
+{ return __lhs + (-__rhs); }
+
+inline constexpr year_month_day_last& year_month_day_last::operator+=(const months& __dm) noexcept { *this = *this + __dm; return *this; }
+inline constexpr year_month_day_last& year_month_day_last::operator-=(const months& __dm) noexcept { *this = *this - __dm; return *this; }
+inline constexpr year_month_day_last& year_month_day_last::operator+=(const years& __dy)  noexcept { *this = *this + __dy; return *this; }
+inline constexpr year_month_day_last& year_month_day_last::operator-=(const years& __dy)  noexcept { *this = *this - __dy; return *this; }
+
+inline constexpr year_month_day::year_month_day(const year_month_day_last& __ymdl) noexcept
+    : __y{__ymdl.year()}, __m{__ymdl.month()}, __d{__ymdl.day()} {}
+
+inline constexpr bool year_month_day::ok() const noexcept
+{
+    if (!__y.ok() || !__m.ok()) return false;
+    return chrono::day{1} <= __d && __d <= (__y / __m / last).day();
+}
+
+class year_month_weekday {
+    chrono::year            __y;
+    chrono::month           __m;
+    chrono::weekday_indexed __wdi;
+public:
+    year_month_weekday() = default;
+    constexpr year_month_weekday(const chrono::year& __yval, const chrono::month& __mval,
+                               const chrono::weekday_indexed& __wdival) noexcept
+        : __y{__yval}, __m{__mval}, __wdi{__wdival} {}
+    constexpr year_month_weekday(const sys_days& __sysd) noexcept
+            : year_month_weekday(__from_days(__sysd.time_since_epoch())) {}
+    inline explicit constexpr year_month_weekday(const local_days& __locd) noexcept
+            : year_month_weekday(__from_days(__locd.time_since_epoch())) {}
+    constexpr year_month_weekday& operator+=(const months& m) noexcept;
+    constexpr year_month_weekday& operator-=(const months& m) noexcept;
+    constexpr year_month_weekday& operator+=(const years& y)  noexcept;
+    constexpr year_month_weekday& operator-=(const years& y)  noexcept;
+
+    inline constexpr chrono::year                       year() const noexcept { return __y; }
+    inline constexpr chrono::month                     month() const noexcept { return __m; }
+    inline constexpr chrono::weekday                 weekday() const noexcept { return __wdi.weekday(); }
+    inline constexpr unsigned                          index() const noexcept { return __wdi.index(); }
+    inline constexpr chrono::weekday_indexed weekday_indexed() const noexcept { return __wdi; }
+
+    inline constexpr                       operator sys_days() const noexcept { return   sys_days{__to_days()}; }
+    inline explicit constexpr operator            local_days() const noexcept { return local_days{__to_days()}; }
+    inline constexpr bool ok() const noexcept
+    {
+        if (!__y.ok() || !__m.ok() || !__wdi.ok()) return false;
+        if (__wdi.index() <= 4) return true;
+        auto __nth_weekday_day =
+            __wdi.weekday() -
+            chrono::weekday{static_cast<sys_days>(__y / __m / 1)} +
+            days{(__wdi.index() - 1) * 7 + 1};
+        return static_cast<unsigned>(__nth_weekday_day.count()) <=
+               static_cast<unsigned>((__y / __m / last).day());
+    }
+
+    static constexpr year_month_weekday __from_days(days __d) noexcept;
+    constexpr days __to_days() const noexcept;
+};
+
+inline constexpr
+year_month_weekday year_month_weekday::__from_days(days __d) noexcept
+{
+    const sys_days      __sysd{__d};
+    const chrono::weekday __wd = chrono::weekday(__sysd);
+    const year_month_day __ymd = year_month_day(__sysd);
+    return year_month_weekday{__ymd.year(), __ymd.month(),
+                              __wd[(static_cast<unsigned>(__ymd.day())-1)/7+1]};
+}
+
+inline constexpr
+days year_month_weekday::__to_days() const noexcept
+{
+    const sys_days __sysd = sys_days(__y/__m/1);
+    return (__sysd + (__wdi.weekday() - chrono::weekday(__sysd) + days{(__wdi.index()-1)*7}))
+                .time_since_epoch();
+}
+
+inline constexpr
+bool operator==(const year_month_weekday& __lhs, const year_month_weekday& __rhs) noexcept
+{ return __lhs.year() == __rhs.year() && __lhs.month() == __rhs.month() && __lhs.weekday_indexed() == __rhs.weekday_indexed(); }
+
+inline constexpr
+bool operator!=(const year_month_weekday& __lhs, const year_month_weekday& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+inline constexpr
+year_month_weekday operator/(const year_month& __lhs, const weekday_indexed& __rhs) noexcept
+{ return year_month_weekday{__lhs.year(), __lhs.month(), __rhs}; }
+
+inline constexpr
+year_month_weekday operator/(const year& __lhs, const month_weekday& __rhs) noexcept
+{ return year_month_weekday{__lhs, __rhs.month(), __rhs.weekday_indexed()}; }
+
+inline constexpr
+year_month_weekday operator/(int __lhs, const month_weekday& __rhs) noexcept
+{ return year(__lhs) / __rhs; }
+
+inline constexpr
+year_month_weekday operator/(const month_weekday& __lhs, const year& __rhs) noexcept
+{ return __rhs / __lhs; }
+
+inline constexpr
+year_month_weekday operator/(const month_weekday& __lhs, int __rhs) noexcept
+{ return year(__rhs) / __lhs; }
+
+
+inline constexpr
+year_month_weekday operator+(const year_month_weekday& __lhs, const months& __rhs) noexcept
+{ return (__lhs.year() / __lhs.month() + __rhs) / __lhs.weekday_indexed(); }
+
+inline constexpr
+year_month_weekday operator+(const months& __lhs, const year_month_weekday& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+inline constexpr
+year_month_weekday operator-(const year_month_weekday& __lhs, const months& __rhs) noexcept
+{ return __lhs + (-__rhs); }
+
+inline constexpr
+year_month_weekday operator+(const year_month_weekday& __lhs, const years& __rhs) noexcept
+{ return year_month_weekday{__lhs.year() + __rhs, __lhs.month(), __lhs.weekday_indexed()}; }
+
+inline constexpr
+year_month_weekday operator+(const years& __lhs, const year_month_weekday& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+inline constexpr
+year_month_weekday operator-(const year_month_weekday& __lhs, const years& __rhs) noexcept
+{ return __lhs + (-__rhs); }
+
+
+inline constexpr year_month_weekday& year_month_weekday::operator+=(const months& __dm) noexcept { *this = *this + __dm; return *this; }
+inline constexpr year_month_weekday& year_month_weekday::operator-=(const months& __dm) noexcept { *this = *this - __dm; return *this; }
+inline constexpr year_month_weekday& year_month_weekday::operator+=(const years& __dy)  noexcept { *this = *this + __dy; return *this; }
+inline constexpr year_month_weekday& year_month_weekday::operator-=(const years& __dy)  noexcept { *this = *this - __dy; return *this; }
+
+class year_month_weekday_last {
+private:
+    chrono::year         __y;
+    chrono::month        __m;
+    chrono::weekday_last __wdl;
+public:
+    constexpr year_month_weekday_last(const chrono::year& __yval, const chrono::month& __mval,
+                                      const chrono::weekday_last& __wdlval) noexcept
+                : __y{__yval}, __m{__mval}, __wdl{__wdlval} {}
+    constexpr year_month_weekday_last& operator+=(const months& __dm) noexcept;
+    constexpr year_month_weekday_last& operator-=(const months& __dm) noexcept;
+    constexpr year_month_weekday_last& operator+=(const years& __dy)  noexcept;
+    constexpr year_month_weekday_last& operator-=(const years& __dy)  noexcept;
+
+    inline constexpr chrono::year                 year() const noexcept { return __y; }
+    inline constexpr chrono::month               month() const noexcept { return __m; }
+    inline constexpr chrono::weekday           weekday() const noexcept { return __wdl.weekday(); }
+    inline constexpr chrono::weekday_last weekday_last() const noexcept { return __wdl; }
+    inline constexpr operator                 sys_days() const noexcept { return   sys_days{__to_days()}; }
+    inline explicit constexpr operator      local_days() const noexcept { return local_days{__to_days()}; }
+    inline constexpr bool ok() const noexcept { return __y.ok() && __m.ok() && __wdl.ok(); }
+
+    constexpr days __to_days() const noexcept;
+
+};
+
+inline constexpr
+days year_month_weekday_last::__to_days() const noexcept
+{
+    const sys_days __last = sys_days{__y/__m/last};
+    return (__last - (chrono::weekday{__last} - __wdl.weekday())).time_since_epoch();
+
+}
+
+inline constexpr
+bool operator==(const year_month_weekday_last& __lhs, const year_month_weekday_last& __rhs) noexcept
+{ return __lhs.year() == __rhs.year() && __lhs.month() == __rhs.month() && __lhs.weekday_last() == __rhs.weekday_last(); }
+
+inline constexpr
+bool operator!=(const year_month_weekday_last& __lhs, const year_month_weekday_last& __rhs) noexcept
+{ return !(__lhs == __rhs); }
+
+
+inline constexpr
+year_month_weekday_last operator/(const year_month& __lhs, const weekday_last& __rhs) noexcept
+{ return year_month_weekday_last{__lhs.year(), __lhs.month(), __rhs}; }
+
+inline constexpr
+year_month_weekday_last operator/(const year& __lhs, const month_weekday_last& __rhs) noexcept
+{ return year_month_weekday_last{__lhs, __rhs.month(), __rhs.weekday_last()}; }
+
+inline constexpr
+year_month_weekday_last operator/(int __lhs, const month_weekday_last& __rhs) noexcept
+{ return year(__lhs) / __rhs; }
+
+inline constexpr
+year_month_weekday_last operator/(const month_weekday_last& __lhs, const year& __rhs) noexcept
+{ return __rhs / __lhs; }
+
+inline constexpr
+year_month_weekday_last operator/(const month_weekday_last& __lhs, int __rhs) noexcept
+{ return year(__rhs) / __lhs; }
+
+
+inline constexpr
+year_month_weekday_last operator+(const year_month_weekday_last& __lhs, const months& __rhs) noexcept
+{ return (__lhs.year() / __lhs.month() + __rhs) / __lhs.weekday_last(); }
+
+inline constexpr
+year_month_weekday_last operator+(const months& __lhs, const year_month_weekday_last& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+inline constexpr
+year_month_weekday_last operator-(const year_month_weekday_last& __lhs, const months& __rhs) noexcept
+{ return __lhs + (-__rhs); }
+
+inline constexpr
+year_month_weekday_last operator+(const year_month_weekday_last& __lhs, const years& __rhs) noexcept
+{ return year_month_weekday_last{__lhs.year() + __rhs, __lhs.month(), __lhs.weekday_last()}; }
+
+inline constexpr
+year_month_weekday_last operator+(const years& __lhs, const year_month_weekday_last& __rhs) noexcept
+{ return __rhs + __lhs; }
+
+inline constexpr
+year_month_weekday_last operator-(const year_month_weekday_last& __lhs, const years& __rhs) noexcept
+{ return __lhs + (-__rhs); }
+
+inline constexpr year_month_weekday_last& year_month_weekday_last::operator+=(const months& __dm) noexcept { *this = *this + __dm; return *this; }
+inline constexpr year_month_weekday_last& year_month_weekday_last::operator-=(const months& __dm) noexcept { *this = *this - __dm; return *this; }
+inline constexpr year_month_weekday_last& year_month_weekday_last::operator+=(const years& __dy)  noexcept { *this = *this + __dy; return *this; }
+inline constexpr year_month_weekday_last& year_month_weekday_last::operator-=(const years& __dy)  noexcept { *this = *this - __dy; return *this; }
+
+
+template <class _Duration>
+class hh_mm_ss
+{
+private:
+    static_assert(__is_duration<_Duration>::value, "template parameter of hh_mm_ss must be a std::chrono::duration");
+    using __CommonType = common_type_t<_Duration, chrono::seconds>;
+
+    static constexpr uint64_t __pow10(unsigned __exp)
+    {
+        uint64_t __ret = 1;
+        for (unsigned __i = 0; __i < __exp; ++__i)
+            __ret *= 10U;
+        return __ret;
+    }
+
+    static constexpr unsigned __width(uint64_t __n, uint64_t __d = 10, unsigned __w = 0)
+    {
+        if (__n >= 2 && __d != 0 && __w < 19)
+            return 1 + __width(__n, __d % __n * 10, __w+1);
+        return 0;
+    }
+
+public:
+    static unsigned constexpr fractional_width = __width(__CommonType::period::den) < 19 ?
+                                                 __width(__CommonType::period::den) : 6u;
+    using precision = duration<typename __CommonType::rep, ratio<1, __pow10(fractional_width)>>;
+
+    constexpr hh_mm_ss() noexcept : hh_mm_ss{_Duration::zero()} {}
+
+    constexpr explicit hh_mm_ss(_Duration __d) noexcept :
+        __is_neg(__d < _Duration(0)),
+        __h(duration_cast<chrono::hours>  (abs(__d))),
+        __m(duration_cast<chrono::minutes>(abs(__d) - hours())),
+        __s(duration_cast<chrono::seconds>(abs(__d) - hours() - minutes())),
+        __f(duration_cast<precision>      (abs(__d) - hours() - minutes() - seconds()))
+        {}
+
+    constexpr bool is_negative()        const noexcept { return __is_neg; }
+    constexpr chrono::hours hours()     const noexcept { return __h; }
+    constexpr chrono::minutes minutes() const noexcept { return __m; }
+    constexpr chrono::seconds seconds() const noexcept { return __s; }
+    constexpr precision subseconds()    const noexcept { return __f; }
+
+    constexpr precision to_duration() const noexcept
+    {
+        auto __dur = __h + __m + __s + __f;
+        return __is_neg ? -__dur : __dur;
+    }
+
+    constexpr explicit operator precision() const noexcept { return to_duration(); }
+
+private:
+    bool            __is_neg;
+    chrono::hours   __h;
+    chrono::minutes __m;
+    chrono::seconds __s;
+    precision       __f;
+};
+
+constexpr bool is_am(const hours& __h) noexcept { return __h >= hours( 0) && __h < hours(12); }
+constexpr bool is_pm(const hours& __h) noexcept { return __h >= hours(12) && __h < hours(24); }
+
+constexpr hours make12(const hours& __h) noexcept
+{
+    if      (__h == hours( 0)) return hours(12);
+    else if (__h <= hours(12)) return __h;
+    else                       return __h - hours(12);
+}
+
+constexpr hours make24(const hours& __h, bool __is_pm) noexcept
+{
+    if (__is_pm)
+        return __h == hours(12) ? __h : __h + hours(12);
+    else
+        return __h == hours(12) ? hours(0) : __h;
+}
+
+#endif // _LIBCPP_STD_VER > 17
+} // chrono
+
+#if _LIBCPP_STD_VER > 11
+// Suffixes for duration literals [time.duration.literals]
+inline namespace literals
+{
+  inline namespace chrono_literals
+  {
+
+    constexpr chrono::hours operator""h(unsigned long long __h)
+    {
+        return chrono::hours(static_cast<chrono::hours::rep>(__h));
+    }
+
+    constexpr chrono::duration<long double, ratio<3600,1>> operator""h(long double __h)
+    {
+        return chrono::duration<long double, ratio<3600,1>>(__h);
+    }
+
+
+    constexpr chrono::minutes operator""min(unsigned long long __m)
+    {
+        return chrono::minutes(static_cast<chrono::minutes::rep>(__m));
+    }
+
+    constexpr chrono::duration<long double, ratio<60,1>> operator""min(long double __m)
+    {
+        return chrono::duration<long double, ratio<60,1>> (__m);
+    }
+
+
+    constexpr chrono::seconds operator""s(unsigned long long __s)
+    {
+        return chrono::seconds(static_cast<chrono::seconds::rep>(__s));
+    }
+
+    constexpr chrono::duration<long double> operator""s(long double __s)
+    {
+        return chrono::duration<long double> (__s);
+    }
+
+
+    constexpr chrono::milliseconds operator""ms(unsigned long long __ms)
+    {
+        return chrono::milliseconds(static_cast<chrono::milliseconds::rep>(__ms));
+    }
+
+    constexpr chrono::duration<long double, milli> operator""ms(long double __ms)
+    {
+        return chrono::duration<long double, milli>(__ms);
+    }
+
+
+    constexpr chrono::microseconds operator""us(unsigned long long __us)
+    {
+        return chrono::microseconds(static_cast<chrono::microseconds::rep>(__us));
+    }
+
+    constexpr chrono::duration<long double, micro> operator""us(long double __us)
+    {
+        return chrono::duration<long double, micro> (__us);
+    }
+
+
+    constexpr chrono::nanoseconds operator""ns(unsigned long long __ns)
+    {
+        return chrono::nanoseconds(static_cast<chrono::nanoseconds::rep>(__ns));
+    }
+
+    constexpr chrono::duration<long double, nano> operator""ns(long double __ns)
+    {
+        return chrono::duration<long double, nano> (__ns);
+    }
+
+#if _LIBCPP_STD_VER > 17
+    constexpr chrono::day operator ""d(unsigned long long __d) noexcept
+    {
+        return chrono::day(static_cast<unsigned>(__d));
+    }
+
+    constexpr chrono::year operator ""y(unsigned long long __y) noexcept
+    {
+        return chrono::year(static_cast<int>(__y));
+    }
+#endif
+}}
+
+namespace chrono { // hoist the literals into namespace std::chrono
+   using namespace literals::chrono_literals;
+}
+
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+
+#ifndef _LIBCPP_CXX03_LANG
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+struct _FilesystemClock {
+#if !defined(_LIBCPP_HAS_NO_INT128)
+  typedef __int128_t rep;
+  typedef nano period;
+#else
+  typedef long long rep;
+  typedef nano period;
+#endif
+
+  typedef chrono::duration<rep, period> duration;
+  typedef chrono::time_point<_FilesystemClock> time_point;
+
+  _LIBCPP_EXPORTED_FROM_ABI
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 const bool is_steady = false;
+
+  _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_FUNC_VIS static time_point now() noexcept;
+
+  _LIBCPP_INLINE_VISIBILITY
+  static time_t to_time_t(const time_point& __t) noexcept {
+      typedef chrono::duration<rep> __secs;
+      return time_t(
+          chrono::duration_cast<__secs>(__t.time_since_epoch()).count());
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  static time_point from_time_t(time_t __t) noexcept {
+      typedef chrono::duration<rep> __secs;
+      return time_point(__secs(__t));
+  }
+};
+_LIBCPP_END_NAMESPACE_FILESYSTEM
+#endif // !_LIBCPP_CXX03_LANG
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_CHRONO
diff --git a/contrib/libs/cxxsupp/libcxx/include/cinttypes b/contrib/libs/cxxsupp/libcxx/include/cinttypes
new file mode 100644
index 00000000000..7ce4a8ad5d8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cinttypes
@@ -0,0 +1,257 @@
+// -*- C++ -*-
+//===--------------------------- cinttypes --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CINTTYPES
+#define _LIBCPP_CINTTYPES
+
+/*
+    cinttypes synopsis
+
+This entire header is C99 / C++0X
+
+#include <cstdint>  // <cinttypes> includes <cstdint>
+
+Macros:
+
+    PRId8
+    PRId16
+    PRId32
+    PRId64
+
+    PRIdLEAST8
+    PRIdLEAST16
+    PRIdLEAST32
+    PRIdLEAST64
+
+    PRIdFAST8
+    PRIdFAST16
+    PRIdFAST32
+    PRIdFAST64
+
+    PRIdMAX
+    PRIdPTR
+
+    PRIi8
+    PRIi16
+    PRIi32
+    PRIi64
+
+    PRIiLEAST8
+    PRIiLEAST16
+    PRIiLEAST32
+    PRIiLEAST64
+
+    PRIiFAST8
+    PRIiFAST16
+    PRIiFAST32
+    PRIiFAST64
+
+    PRIiMAX
+    PRIiPTR
+
+    PRIo8
+    PRIo16
+    PRIo32
+    PRIo64
+
+    PRIoLEAST8
+    PRIoLEAST16
+    PRIoLEAST32
+    PRIoLEAST64
+
+    PRIoFAST8
+    PRIoFAST16
+    PRIoFAST32
+    PRIoFAST64
+
+    PRIoMAX
+    PRIoPTR
+
+    PRIu8
+    PRIu16
+    PRIu32
+    PRIu64
+
+    PRIuLEAST8
+    PRIuLEAST16
+    PRIuLEAST32
+    PRIuLEAST64
+
+    PRIuFAST8
+    PRIuFAST16
+    PRIuFAST32
+    PRIuFAST64
+
+    PRIuMAX
+    PRIuPTR
+
+    PRIx8
+    PRIx16
+    PRIx32
+    PRIx64
+
+    PRIxLEAST8
+    PRIxLEAST16
+    PRIxLEAST32
+    PRIxLEAST64
+
+    PRIxFAST8
+    PRIxFAST16
+    PRIxFAST32
+    PRIxFAST64
+
+    PRIxMAX
+    PRIxPTR
+
+    PRIX8
+    PRIX16
+    PRIX32
+    PRIX64
+
+    PRIXLEAST8
+    PRIXLEAST16
+    PRIXLEAST32
+    PRIXLEAST64
+
+    PRIXFAST8
+    PRIXFAST16
+    PRIXFAST32
+    PRIXFAST64
+
+    PRIXMAX
+    PRIXPTR
+
+    SCNd8
+    SCNd16
+    SCNd32
+    SCNd64
+
+    SCNdLEAST8
+    SCNdLEAST16
+    SCNdLEAST32
+    SCNdLEAST64
+
+    SCNdFAST8
+    SCNdFAST16
+    SCNdFAST32
+    SCNdFAST64
+
+    SCNdMAX
+    SCNdPTR
+
+    SCNi8
+    SCNi16
+    SCNi32
+    SCNi64
+
+    SCNiLEAST8
+    SCNiLEAST16
+    SCNiLEAST32
+    SCNiLEAST64
+
+    SCNiFAST8
+    SCNiFAST16
+    SCNiFAST32
+    SCNiFAST64
+
+    SCNiMAX
+    SCNiPTR
+
+    SCNo8
+    SCNo16
+    SCNo32
+    SCNo64
+
+    SCNoLEAST8
+    SCNoLEAST16
+    SCNoLEAST32
+    SCNoLEAST64
+
+    SCNoFAST8
+    SCNoFAST16
+    SCNoFAST32
+    SCNoFAST64
+
+    SCNoMAX
+    SCNoPTR
+
+    SCNu8
+    SCNu16
+    SCNu32
+    SCNu64
+
+    SCNuLEAST8
+    SCNuLEAST16
+    SCNuLEAST32
+    SCNuLEAST64
+
+    SCNuFAST8
+    SCNuFAST16
+    SCNuFAST32
+    SCNuFAST64
+
+    SCNuMAX
+    SCNuPTR
+
+    SCNx8
+    SCNx16
+    SCNx32
+    SCNx64
+
+    SCNxLEAST8
+    SCNxLEAST16
+    SCNxLEAST32
+    SCNxLEAST64
+
+    SCNxFAST8
+    SCNxFAST16
+    SCNxFAST32
+    SCNxFAST64
+
+    SCNxMAX
+    SCNxPTR
+
+namespace std
+{
+
+Types:
+
+    imaxdiv_t
+
+intmax_t  imaxabs(intmax_t j);
+imaxdiv_t imaxdiv(intmax_t numer, intmax_t denom);
+intmax_t  strtoimax(const char* restrict nptr, char** restrict endptr, int base);
+uintmax_t strtoumax(const char* restrict nptr, char** restrict endptr, int base);
+intmax_t  wcstoimax(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);
+uintmax_t wcstoumax(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);
+
+}  // std
+*/
+
+#include <__config>
+#include <cstdint>
+#include <inttypes.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::imaxdiv_t _LIBCPP_USING_IF_EXISTS;
+using ::imaxabs _LIBCPP_USING_IF_EXISTS;
+using ::imaxdiv _LIBCPP_USING_IF_EXISTS;
+using ::strtoimax _LIBCPP_USING_IF_EXISTS;
+using ::strtoumax _LIBCPP_USING_IF_EXISTS;
+using ::wcstoimax _LIBCPP_USING_IF_EXISTS;
+using ::wcstoumax _LIBCPP_USING_IF_EXISTS;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CINTTYPES
diff --git a/contrib/libs/cxxsupp/libcxx/include/ciso646 b/contrib/libs/cxxsupp/libcxx/include/ciso646
new file mode 100644
index 00000000000..c37f6379746
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/ciso646
@@ -0,0 +1,24 @@
+// -*- C++ -*-
+//===--------------------------- ciso646 ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CISO646
+#define _LIBCPP_CISO646
+
+/*
+    ciso646 synopsis
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#endif // _LIBCPP_CISO646
diff --git a/contrib/libs/cxxsupp/libcxx/include/climits b/contrib/libs/cxxsupp/libcxx/include/climits
new file mode 100644
index 00000000000..217ec6286e8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/climits
@@ -0,0 +1,47 @@
+// -*- C++ -*-
+//===--------------------------- climits ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CLIMITS
+#define _LIBCPP_CLIMITS
+
+/*
+    climits synopsis
+
+Macros:
+
+    CHAR_BIT
+    SCHAR_MIN
+    SCHAR_MAX
+    UCHAR_MAX
+    CHAR_MIN
+    CHAR_MAX
+    MB_LEN_MAX
+    SHRT_MIN
+    SHRT_MAX
+    USHRT_MAX
+    INT_MIN
+    INT_MAX
+    UINT_MAX
+    LONG_MIN
+    LONG_MAX
+    ULONG_MAX
+    LLONG_MIN   // C99
+    LLONG_MAX   // C99
+    ULLONG_MAX  // C99
+
+*/
+
+#include <__config>
+#include <limits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#endif // _LIBCPP_CLIMITS
diff --git a/contrib/libs/cxxsupp/libcxx/include/clocale b/contrib/libs/cxxsupp/libcxx/include/clocale
new file mode 100644
index 00000000000..ea4f8014bb2
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/clocale
@@ -0,0 +1,52 @@
+// -*- C++ -*-
+//===--------------------------- clocale ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CLOCALE
+#define _LIBCPP_CLOCALE
+
+/*
+    clocale synopsis
+
+Macros:
+
+    LC_ALL
+    LC_COLLATE
+    LC_CTYPE
+    LC_MONETARY
+    LC_NUMERIC
+    LC_TIME
+    NULL
+
+namespace std
+{
+
+struct lconv;
+char* setlocale(int category, const char* locale);
+lconv* localeconv();
+
+}  // std
+
+*/
+
+#include <__config>
+#include <locale.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::lconv _LIBCPP_USING_IF_EXISTS;
+using ::setlocale _LIBCPP_USING_IF_EXISTS;
+using ::localeconv _LIBCPP_USING_IF_EXISTS;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CLOCALE
diff --git a/contrib/libs/cxxsupp/libcxx/include/cmath b/contrib/libs/cxxsupp/libcxx/include/cmath
new file mode 100644
index 00000000000..e14905c57cf
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cmath
@@ -0,0 +1,675 @@
+// -*- C++ -*-
+//===---------------------------- cmath -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CMATH
+#define _LIBCPP_CMATH
+
+/*
+    cmath synopsis
+
+Macros:
+
+    HUGE_VAL
+    HUGE_VALF               // C99
+    HUGE_VALL               // C99
+    INFINITY                // C99
+    NAN                     // C99
+    FP_INFINITE             // C99
+    FP_NAN                  // C99
+    FP_NORMAL               // C99
+    FP_SUBNORMAL            // C99
+    FP_ZERO                 // C99
+    FP_FAST_FMA             // C99
+    FP_FAST_FMAF            // C99
+    FP_FAST_FMAL            // C99
+    FP_ILOGB0               // C99
+    FP_ILOGBNAN             // C99
+    MATH_ERRNO              // C99
+    MATH_ERREXCEPT          // C99
+    math_errhandling        // C99
+
+namespace std
+{
+
+Types:
+
+    float_t                 // C99
+    double_t                // C99
+
+// C90
+
+floating_point abs(floating_point x);
+
+floating_point acos (arithmetic x);
+float          acosf(float x);
+long double    acosl(long double x);
+
+floating_point asin (arithmetic x);
+float          asinf(float x);
+long double    asinl(long double x);
+
+floating_point atan (arithmetic x);
+float          atanf(float x);
+long double    atanl(long double x);
+
+floating_point atan2 (arithmetic y, arithmetic x);
+float          atan2f(float y, float x);
+long double    atan2l(long double y, long double x);
+
+floating_point ceil (arithmetic x);
+float          ceilf(float x);
+long double    ceill(long double x);
+
+floating_point cos (arithmetic x);
+float          cosf(float x);
+long double    cosl(long double x);
+
+floating_point cosh (arithmetic x);
+float          coshf(float x);
+long double    coshl(long double x);
+
+floating_point exp (arithmetic x);
+float          expf(float x);
+long double    expl(long double x);
+
+floating_point fabs (arithmetic x);
+float          fabsf(float x);
+long double    fabsl(long double x);
+
+floating_point floor (arithmetic x);
+float          floorf(float x);
+long double    floorl(long double x);
+
+floating_point fmod (arithmetic x, arithmetic y);
+float          fmodf(float x, float y);
+long double    fmodl(long double x, long double y);
+
+floating_point frexp (arithmetic value, int* exp);
+float          frexpf(float value, int* exp);
+long double    frexpl(long double value, int* exp);
+
+floating_point ldexp (arithmetic value, int exp);
+float          ldexpf(float value, int exp);
+long double    ldexpl(long double value, int exp);
+
+floating_point log (arithmetic x);
+float          logf(float x);
+long double    logl(long double x);
+
+floating_point log10 (arithmetic x);
+float          log10f(float x);
+long double    log10l(long double x);
+
+floating_point modf (floating_point value, floating_point* iptr);
+float          modff(float value, float* iptr);
+long double    modfl(long double value, long double* iptr);
+
+floating_point pow (arithmetic x, arithmetic y);
+float          powf(float x, float y);
+long double    powl(long double x, long double y);
+
+floating_point sin (arithmetic x);
+float          sinf(float x);
+long double    sinl(long double x);
+
+floating_point sinh (arithmetic x);
+float          sinhf(float x);
+long double    sinhl(long double x);
+
+floating_point sqrt (arithmetic x);
+float          sqrtf(float x);
+long double    sqrtl(long double x);
+
+floating_point tan (arithmetic x);
+float          tanf(float x);
+long double    tanl(long double x);
+
+floating_point tanh (arithmetic x);
+float          tanhf(float x);
+long double    tanhl(long double x);
+
+//  C99
+
+bool signbit(arithmetic x);
+
+int fpclassify(arithmetic x);
+
+bool isfinite(arithmetic x);
+bool isinf(arithmetic x);
+bool isnan(arithmetic x);
+bool isnormal(arithmetic x);
+
+bool isgreater(arithmetic x, arithmetic y);
+bool isgreaterequal(arithmetic x, arithmetic y);
+bool isless(arithmetic x, arithmetic y);
+bool islessequal(arithmetic x, arithmetic y);
+bool islessgreater(arithmetic x, arithmetic y);
+bool isunordered(arithmetic x, arithmetic y);
+
+floating_point acosh (arithmetic x);
+float          acoshf(float x);
+long double    acoshl(long double x);
+
+floating_point asinh (arithmetic x);
+float          asinhf(float x);
+long double    asinhl(long double x);
+
+floating_point atanh (arithmetic x);
+float          atanhf(float x);
+long double    atanhl(long double x);
+
+floating_point cbrt (arithmetic x);
+float          cbrtf(float x);
+long double    cbrtl(long double x);
+
+floating_point copysign (arithmetic x, arithmetic y);
+float          copysignf(float x, float y);
+long double    copysignl(long double x, long double y);
+
+floating_point erf (arithmetic x);
+float          erff(float x);
+long double    erfl(long double x);
+
+floating_point erfc (arithmetic x);
+float          erfcf(float x);
+long double    erfcl(long double x);
+
+floating_point exp2 (arithmetic x);
+float          exp2f(float x);
+long double    exp2l(long double x);
+
+floating_point expm1 (arithmetic x);
+float          expm1f(float x);
+long double    expm1l(long double x);
+
+floating_point fdim (arithmetic x, arithmetic y);
+float          fdimf(float x, float y);
+long double    fdiml(long double x, long double y);
+
+floating_point fma (arithmetic x, arithmetic y, arithmetic z);
+float          fmaf(float x, float y, float z);
+long double    fmal(long double x, long double y, long double z);
+
+floating_point fmax (arithmetic x, arithmetic y);
+float          fmaxf(float x, float y);
+long double    fmaxl(long double x, long double y);
+
+floating_point fmin (arithmetic x, arithmetic y);
+float          fminf(float x, float y);
+long double    fminl(long double x, long double y);
+
+floating_point hypot (arithmetic x, arithmetic y);
+float          hypotf(float x, float y);
+long double    hypotl(long double x, long double y);
+
+double       hypot(double x, double y, double z);                // C++17
+float        hypot(float x, float y, float z);                   // C++17
+long double  hypot(long double x, long double y, long double z); // C++17
+
+int ilogb (arithmetic x);
+int ilogbf(float x);
+int ilogbl(long double x);
+
+floating_point lgamma (arithmetic x);
+float          lgammaf(float x);
+long double    lgammal(long double x);
+
+long long llrint (arithmetic x);
+long long llrintf(float x);
+long long llrintl(long double x);
+
+long long llround (arithmetic x);
+long long llroundf(float x);
+long long llroundl(long double x);
+
+floating_point log1p (arithmetic x);
+float          log1pf(float x);
+long double    log1pl(long double x);
+
+floating_point log2 (arithmetic x);
+float          log2f(float x);
+long double    log2l(long double x);
+
+floating_point logb (arithmetic x);
+float          logbf(float x);
+long double    logbl(long double x);
+
+long lrint (arithmetic x);
+long lrintf(float x);
+long lrintl(long double x);
+
+long lround (arithmetic x);
+long lroundf(float x);
+long lroundl(long double x);
+
+double      nan (const char* str);
+float       nanf(const char* str);
+long double nanl(const char* str);
+
+floating_point nearbyint (arithmetic x);
+float          nearbyintf(float x);
+long double    nearbyintl(long double x);
+
+floating_point nextafter (arithmetic x, arithmetic y);
+float          nextafterf(float x, float y);
+long double    nextafterl(long double x, long double y);
+
+floating_point nexttoward (arithmetic x, long double y);
+float          nexttowardf(float x, long double y);
+long double    nexttowardl(long double x, long double y);
+
+floating_point remainder (arithmetic x, arithmetic y);
+float          remainderf(float x, float y);
+long double    remainderl(long double x, long double y);
+
+floating_point remquo (arithmetic x, arithmetic y, int* pquo);
+float          remquof(float x, float y, int* pquo);
+long double    remquol(long double x, long double y, int* pquo);
+
+floating_point rint (arithmetic x);
+float          rintf(float x);
+long double    rintl(long double x);
+
+floating_point round (arithmetic x);
+float          roundf(float x);
+long double    roundl(long double x);
+
+floating_point scalbln (arithmetic x, long ex);
+float          scalblnf(float x, long ex);
+long double    scalblnl(long double x, long ex);
+
+floating_point scalbn (arithmetic x, int ex);
+float          scalbnf(float x, int ex);
+long double    scalbnl(long double x, int ex);
+
+floating_point tgamma (arithmetic x);
+float          tgammaf(float x);
+long double    tgammal(long double x);
+
+floating_point trunc (arithmetic x);
+float          truncf(float x);
+long double    truncl(long double x);
+
+constexpr float       lerp(float a, float b, float t) noexcept;                   // C++20
+constexpr double      lerp(double a, double b, double t) noexcept;                // C++20
+constexpr long double lerp(long double a, long double b, long double t) noexcept; // C++20
+
+}  // std
+
+*/
+
+#include <__config>
+#include <math.h>
+#include <version>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::signbit _LIBCPP_USING_IF_EXISTS;
+using ::fpclassify _LIBCPP_USING_IF_EXISTS;
+using ::isfinite _LIBCPP_USING_IF_EXISTS;
+using ::isinf _LIBCPP_USING_IF_EXISTS;
+using ::isnan _LIBCPP_USING_IF_EXISTS;
+using ::isnormal _LIBCPP_USING_IF_EXISTS;
+using ::isgreater _LIBCPP_USING_IF_EXISTS;
+using ::isgreaterequal _LIBCPP_USING_IF_EXISTS;
+using ::isless _LIBCPP_USING_IF_EXISTS;
+using ::islessequal _LIBCPP_USING_IF_EXISTS;
+using ::islessgreater _LIBCPP_USING_IF_EXISTS;
+using ::isunordered _LIBCPP_USING_IF_EXISTS;
+using ::isunordered _LIBCPP_USING_IF_EXISTS;
+
+using ::float_t _LIBCPP_USING_IF_EXISTS;
+using ::double_t _LIBCPP_USING_IF_EXISTS;
+
+using ::abs _LIBCPP_USING_IF_EXISTS;
+
+using ::acos _LIBCPP_USING_IF_EXISTS;
+using ::acosf _LIBCPP_USING_IF_EXISTS;
+using ::asin _LIBCPP_USING_IF_EXISTS;
+using ::asinf _LIBCPP_USING_IF_EXISTS;
+using ::atan _LIBCPP_USING_IF_EXISTS;
+using ::atanf _LIBCPP_USING_IF_EXISTS;
+using ::atan2 _LIBCPP_USING_IF_EXISTS;
+using ::atan2f _LIBCPP_USING_IF_EXISTS;
+using ::ceil _LIBCPP_USING_IF_EXISTS;
+using ::ceilf _LIBCPP_USING_IF_EXISTS;
+using ::cos _LIBCPP_USING_IF_EXISTS;
+using ::cosf _LIBCPP_USING_IF_EXISTS;
+using ::cosh _LIBCPP_USING_IF_EXISTS;
+using ::coshf _LIBCPP_USING_IF_EXISTS;
+
+using ::exp _LIBCPP_USING_IF_EXISTS;
+using ::expf _LIBCPP_USING_IF_EXISTS;
+
+using ::fabs _LIBCPP_USING_IF_EXISTS;
+using ::fabsf _LIBCPP_USING_IF_EXISTS;
+using ::floor _LIBCPP_USING_IF_EXISTS;
+using ::floorf _LIBCPP_USING_IF_EXISTS;
+
+using ::fmod _LIBCPP_USING_IF_EXISTS;
+using ::fmodf _LIBCPP_USING_IF_EXISTS;
+
+using ::frexp _LIBCPP_USING_IF_EXISTS;
+using ::frexpf _LIBCPP_USING_IF_EXISTS;
+using ::ldexp _LIBCPP_USING_IF_EXISTS;
+using ::ldexpf _LIBCPP_USING_IF_EXISTS;
+
+using ::log _LIBCPP_USING_IF_EXISTS;
+using ::logf _LIBCPP_USING_IF_EXISTS;
+
+using ::log10 _LIBCPP_USING_IF_EXISTS;
+using ::log10f _LIBCPP_USING_IF_EXISTS;
+using ::modf _LIBCPP_USING_IF_EXISTS;
+using ::modff _LIBCPP_USING_IF_EXISTS;
+
+using ::pow _LIBCPP_USING_IF_EXISTS;
+using ::powf _LIBCPP_USING_IF_EXISTS;
+
+using ::sin _LIBCPP_USING_IF_EXISTS;
+using ::sinf _LIBCPP_USING_IF_EXISTS;
+using ::sinh _LIBCPP_USING_IF_EXISTS;
+using ::sinhf _LIBCPP_USING_IF_EXISTS;
+
+using ::sqrt _LIBCPP_USING_IF_EXISTS;
+using ::sqrtf _LIBCPP_USING_IF_EXISTS;
+using ::tan _LIBCPP_USING_IF_EXISTS;
+using ::tanf _LIBCPP_USING_IF_EXISTS;
+
+using ::tanh _LIBCPP_USING_IF_EXISTS;
+using ::tanhf _LIBCPP_USING_IF_EXISTS;
+
+using ::acosh _LIBCPP_USING_IF_EXISTS;
+using ::acoshf _LIBCPP_USING_IF_EXISTS;
+using ::asinh _LIBCPP_USING_IF_EXISTS;
+using ::asinhf _LIBCPP_USING_IF_EXISTS;
+using ::atanh _LIBCPP_USING_IF_EXISTS;
+using ::atanhf _LIBCPP_USING_IF_EXISTS;
+using ::cbrt _LIBCPP_USING_IF_EXISTS;
+using ::cbrtf _LIBCPP_USING_IF_EXISTS;
+
+using ::copysign _LIBCPP_USING_IF_EXISTS;
+using ::copysignf _LIBCPP_USING_IF_EXISTS;
+
+using ::erf _LIBCPP_USING_IF_EXISTS;
+using ::erff _LIBCPP_USING_IF_EXISTS;
+using ::erfc _LIBCPP_USING_IF_EXISTS;
+using ::erfcf _LIBCPP_USING_IF_EXISTS;
+using ::exp2 _LIBCPP_USING_IF_EXISTS;
+using ::exp2f _LIBCPP_USING_IF_EXISTS;
+using ::expm1 _LIBCPP_USING_IF_EXISTS;
+using ::expm1f _LIBCPP_USING_IF_EXISTS;
+using ::fdim _LIBCPP_USING_IF_EXISTS;
+using ::fdimf _LIBCPP_USING_IF_EXISTS;
+using ::fmaf _LIBCPP_USING_IF_EXISTS;
+using ::fma _LIBCPP_USING_IF_EXISTS;
+using ::fmax _LIBCPP_USING_IF_EXISTS;
+using ::fmaxf _LIBCPP_USING_IF_EXISTS;
+using ::fmin _LIBCPP_USING_IF_EXISTS;
+using ::fminf _LIBCPP_USING_IF_EXISTS;
+using ::hypot _LIBCPP_USING_IF_EXISTS;
+using ::hypotf _LIBCPP_USING_IF_EXISTS;
+using ::ilogb _LIBCPP_USING_IF_EXISTS;
+using ::ilogbf _LIBCPP_USING_IF_EXISTS;
+using ::lgamma _LIBCPP_USING_IF_EXISTS;
+using ::lgammaf _LIBCPP_USING_IF_EXISTS;
+using ::llrint _LIBCPP_USING_IF_EXISTS;
+using ::llrintf _LIBCPP_USING_IF_EXISTS;
+using ::llround _LIBCPP_USING_IF_EXISTS;
+using ::llroundf _LIBCPP_USING_IF_EXISTS;
+using ::log1p _LIBCPP_USING_IF_EXISTS;
+using ::log1pf _LIBCPP_USING_IF_EXISTS;
+using ::log2 _LIBCPP_USING_IF_EXISTS;
+using ::log2f _LIBCPP_USING_IF_EXISTS;
+using ::logb _LIBCPP_USING_IF_EXISTS;
+using ::logbf _LIBCPP_USING_IF_EXISTS;
+using ::lrint _LIBCPP_USING_IF_EXISTS;
+using ::lrintf _LIBCPP_USING_IF_EXISTS;
+using ::lround _LIBCPP_USING_IF_EXISTS;
+using ::lroundf _LIBCPP_USING_IF_EXISTS;
+
+using ::nan _LIBCPP_USING_IF_EXISTS;
+using ::nanf _LIBCPP_USING_IF_EXISTS;
+
+using ::nearbyint _LIBCPP_USING_IF_EXISTS;
+using ::nearbyintf _LIBCPP_USING_IF_EXISTS;
+using ::nextafter _LIBCPP_USING_IF_EXISTS;
+using ::nextafterf _LIBCPP_USING_IF_EXISTS;
+using ::nexttoward _LIBCPP_USING_IF_EXISTS;
+using ::nexttowardf _LIBCPP_USING_IF_EXISTS;
+using ::remainder _LIBCPP_USING_IF_EXISTS;
+using ::remainderf _LIBCPP_USING_IF_EXISTS;
+using ::remquo _LIBCPP_USING_IF_EXISTS;
+using ::remquof _LIBCPP_USING_IF_EXISTS;
+using ::rint _LIBCPP_USING_IF_EXISTS;
+using ::rintf _LIBCPP_USING_IF_EXISTS;
+using ::round _LIBCPP_USING_IF_EXISTS;
+using ::roundf _LIBCPP_USING_IF_EXISTS;
+using ::scalbln _LIBCPP_USING_IF_EXISTS;
+using ::scalblnf _LIBCPP_USING_IF_EXISTS;
+using ::scalbn _LIBCPP_USING_IF_EXISTS;
+using ::scalbnf _LIBCPP_USING_IF_EXISTS;
+using ::tgamma _LIBCPP_USING_IF_EXISTS;
+using ::tgammaf _LIBCPP_USING_IF_EXISTS;
+using ::trunc _LIBCPP_USING_IF_EXISTS;
+using ::truncf _LIBCPP_USING_IF_EXISTS;
+
+using ::acosl _LIBCPP_USING_IF_EXISTS;
+using ::asinl _LIBCPP_USING_IF_EXISTS;
+using ::atanl _LIBCPP_USING_IF_EXISTS;
+using ::atan2l _LIBCPP_USING_IF_EXISTS;
+using ::ceill _LIBCPP_USING_IF_EXISTS;
+using ::cosl _LIBCPP_USING_IF_EXISTS;
+using ::coshl _LIBCPP_USING_IF_EXISTS;
+using ::expl _LIBCPP_USING_IF_EXISTS;
+using ::fabsl _LIBCPP_USING_IF_EXISTS;
+using ::floorl _LIBCPP_USING_IF_EXISTS;
+using ::fmodl _LIBCPP_USING_IF_EXISTS;
+using ::frexpl _LIBCPP_USING_IF_EXISTS;
+using ::ldexpl _LIBCPP_USING_IF_EXISTS;
+using ::logl _LIBCPP_USING_IF_EXISTS;
+using ::log10l _LIBCPP_USING_IF_EXISTS;
+using ::modfl _LIBCPP_USING_IF_EXISTS;
+using ::powl _LIBCPP_USING_IF_EXISTS;
+using ::sinl _LIBCPP_USING_IF_EXISTS;
+using ::sinhl _LIBCPP_USING_IF_EXISTS;
+using ::sqrtl _LIBCPP_USING_IF_EXISTS;
+using ::tanl _LIBCPP_USING_IF_EXISTS;
+
+using ::tanhl _LIBCPP_USING_IF_EXISTS;
+using ::acoshl _LIBCPP_USING_IF_EXISTS;
+using ::asinhl _LIBCPP_USING_IF_EXISTS;
+using ::atanhl _LIBCPP_USING_IF_EXISTS;
+using ::cbrtl _LIBCPP_USING_IF_EXISTS;
+
+using ::copysignl _LIBCPP_USING_IF_EXISTS;
+
+using ::erfl _LIBCPP_USING_IF_EXISTS;
+using ::erfcl _LIBCPP_USING_IF_EXISTS;
+using ::exp2l _LIBCPP_USING_IF_EXISTS;
+using ::expm1l _LIBCPP_USING_IF_EXISTS;
+using ::fdiml _LIBCPP_USING_IF_EXISTS;
+using ::fmal _LIBCPP_USING_IF_EXISTS;
+using ::fmaxl _LIBCPP_USING_IF_EXISTS;
+using ::fminl _LIBCPP_USING_IF_EXISTS;
+using ::hypotl _LIBCPP_USING_IF_EXISTS;
+using ::ilogbl _LIBCPP_USING_IF_EXISTS;
+using ::lgammal _LIBCPP_USING_IF_EXISTS;
+using ::llrintl _LIBCPP_USING_IF_EXISTS;
+using ::llroundl _LIBCPP_USING_IF_EXISTS;
+using ::log1pl _LIBCPP_USING_IF_EXISTS;
+using ::log2l _LIBCPP_USING_IF_EXISTS;
+using ::logbl _LIBCPP_USING_IF_EXISTS;
+using ::lrintl _LIBCPP_USING_IF_EXISTS;
+using ::lroundl _LIBCPP_USING_IF_EXISTS;
+using ::nanl _LIBCPP_USING_IF_EXISTS;
+using ::nearbyintl _LIBCPP_USING_IF_EXISTS;
+using ::nextafterl _LIBCPP_USING_IF_EXISTS;
+using ::nexttowardl _LIBCPP_USING_IF_EXISTS;
+using ::remainderl _LIBCPP_USING_IF_EXISTS;
+using ::remquol _LIBCPP_USING_IF_EXISTS;
+using ::rintl _LIBCPP_USING_IF_EXISTS;
+using ::roundl _LIBCPP_USING_IF_EXISTS;
+using ::scalblnl _LIBCPP_USING_IF_EXISTS;
+using ::scalbnl _LIBCPP_USING_IF_EXISTS;
+using ::tgammal _LIBCPP_USING_IF_EXISTS;
+using ::truncl _LIBCPP_USING_IF_EXISTS;
+
+#if _LIBCPP_STD_VER > 14
+inline _LIBCPP_INLINE_VISIBILITY float       hypot(       float x,       float y,       float z ) { return sqrt(x*x + y*y + z*z); }
+inline _LIBCPP_INLINE_VISIBILITY double      hypot(      double x,      double y,      double z ) { return sqrt(x*x + y*y + z*z); }
+inline _LIBCPP_INLINE_VISIBILITY long double hypot( long double x, long double y, long double z ) { return sqrt(x*x + y*y + z*z); }
+
+template <class _A1, class _A2, class _A3>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if_t
+<
+    is_arithmetic<_A1>::value &&
+    is_arithmetic<_A2>::value &&
+    is_arithmetic<_A3>::value,
+    __promote<_A1, _A2, _A3>
+>::type
+hypot(_A1 __lcpp_x, _A2 __lcpp_y, _A3 __lcpp_z) _NOEXCEPT
+{
+    typedef typename __promote<_A1, _A2, _A3>::type __result_type;
+    static_assert((!(is_same<_A1, __result_type>::value &&
+                     is_same<_A2, __result_type>::value &&
+                     is_same<_A3, __result_type>::value)), "");
+    return hypot((__result_type)__lcpp_x, (__result_type)__lcpp_y, (__result_type)__lcpp_z);
+}
+#endif
+
+template <class _A1>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR typename enable_if<is_floating_point<_A1>::value, bool>::type
+__libcpp_isnan_or_builtin(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_isnan)
+    return __builtin_isnan(__lcpp_x);
+#else
+    return isnan(__lcpp_x);
+#endif
+}
+
+template <class _A1>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR typename enable_if<!is_floating_point<_A1>::value, bool>::type
+__libcpp_isnan_or_builtin(_A1 __lcpp_x) _NOEXCEPT
+{
+    return isnan(__lcpp_x);
+}
+
+template <class _A1>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR typename enable_if<is_floating_point<_A1>::value, bool>::type
+__libcpp_isinf_or_builtin(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_isinf)
+    return __builtin_isinf(__lcpp_x);
+#else
+    return isinf(__lcpp_x);
+#endif
+}
+
+template <class _A1>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR typename enable_if<!is_floating_point<_A1>::value, bool>::type
+__libcpp_isinf_or_builtin(_A1 __lcpp_x) _NOEXCEPT
+{
+    return isinf(__lcpp_x);
+}
+
+template <class _A1>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR typename enable_if<is_floating_point<_A1>::value, bool>::type
+__libcpp_isfinite_or_builtin(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_isfinite)
+    return __builtin_isfinite(__lcpp_x);
+#else
+    return isfinite(__lcpp_x);
+#endif
+}
+
+template <class _A1>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR typename enable_if<!is_floating_point<_A1>::value, bool>::type
+__libcpp_isfinite_or_builtin(_A1 __lcpp_x) _NOEXCEPT
+{
+    return isfinite(__lcpp_x);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <typename _Fp>
+constexpr
+_Fp __lerp(_Fp __a, _Fp __b, _Fp __t) noexcept {
+    if ((__a <= 0 && __b >= 0) || (__a >= 0 && __b <= 0))
+        return __t * __b + (1 - __t) * __a;
+
+    if (__t == 1) return __b;
+    const _Fp __x = __a + __t * (__b - __a);
+    if ((__t > 1) == (__b > __a))
+    	return __b < __x ? __x : __b;
+    else
+    	return __x < __b ? __x : __b;
+}
+
+constexpr float
+lerp(float __a, float __b, float __t)                   _NOEXCEPT { return __lerp(__a, __b, __t); }
+
+constexpr double
+lerp(double __a, double __b, double __t)                _NOEXCEPT { return __lerp(__a, __b, __t); }
+
+constexpr long double
+lerp(long double __a, long double __b, long double __t) _NOEXCEPT { return __lerp(__a, __b, __t); }
+
+#endif // _LIBCPP_STD_VER > 17
+
+template <class _IntT, class _FloatT,
+    bool _FloatBigger = (numeric_limits<_FloatT>::digits > numeric_limits<_IntT>::digits),
+    int _Bits = (numeric_limits<_IntT>::digits - numeric_limits<_FloatT>::digits)>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR _IntT __max_representable_int_for_float() _NOEXCEPT {
+  static_assert(is_floating_point<_FloatT>::value, "must be a floating point type");
+  static_assert(is_integral<_IntT>::value, "must be an integral type");
+  static_assert(numeric_limits<_FloatT>::radix == 2, "FloatT has incorrect radix");
+  static_assert((_IsSame<_FloatT, float>::value || _IsSame<_FloatT, double>::value
+                 || _IsSame<_FloatT,long double>::value), "unsupported floating point type");
+  return _FloatBigger ? numeric_limits<_IntT>::max() :  (numeric_limits<_IntT>::max() >> _Bits << _Bits);
+}
+
+// Convert a floating point number to the specified integral type after
+// clamping to the integral types representable range.
+//
+// The behavior is undefined if `__r` is NaN.
+template <class _IntT, class _RealT>
+_LIBCPP_INLINE_VISIBILITY
+_IntT __clamp_to_integral(_RealT __r) _NOEXCEPT {
+  using _Lim = numeric_limits<_IntT>;
+  const _IntT _MaxVal = __max_representable_int_for_float<_IntT, _RealT>();
+  if (__r >= ::nextafter(static_cast<_RealT>(_MaxVal), INFINITY)) {
+    return _Lim::max();
+  } else if (__r <= _Lim::lowest()) {
+    return _Lim::min();
+  }
+  return static_cast<_IntT>(__r);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_CMATH
diff --git a/contrib/libs/cxxsupp/libcxx/include/codecvt b/contrib/libs/cxxsupp/libcxx/include/codecvt
new file mode 100644
index 00000000000..4ae07be3f82
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/codecvt
@@ -0,0 +1,579 @@
+// -*- C++ -*-
+//===-------------------------- codecvt -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CODECVT
+#define _LIBCPP_CODECVT
+
+/*
+    codecvt synopsis
+
+namespace std
+{
+
+enum codecvt_mode
+{
+    consume_header = 4,
+    generate_header = 2,
+    little_endian = 1
+};
+
+template <class Elem, unsigned long Maxcode = 0x10ffff,
+          codecvt_mode Mode = (codecvt_mode)0>
+class codecvt_utf8
+    : public codecvt<Elem, char, mbstate_t>
+{
+    explicit codecvt_utf8(size_t refs = 0);
+    ~codecvt_utf8();
+};
+
+template <class Elem, unsigned long Maxcode = 0x10ffff,
+          codecvt_mode Mode = (codecvt_mode)0>
+class codecvt_utf16
+    : public codecvt<Elem, char, mbstate_t>
+{
+    explicit codecvt_utf16(size_t refs = 0);
+    ~codecvt_utf16();
+};
+
+template <class Elem, unsigned long Maxcode = 0x10ffff,
+          codecvt_mode Mode = (codecvt_mode)0>
+class codecvt_utf8_utf16
+    : public codecvt<Elem, char, mbstate_t>
+{
+    explicit codecvt_utf8_utf16(size_t refs = 0);
+    ~codecvt_utf8_utf16();
+};
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__locale>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+enum codecvt_mode
+{
+    consume_header = 4,
+    generate_header = 2,
+    little_endian = 1
+};
+
+// codecvt_utf8
+
+template <class _Elem> class __codecvt_utf8;
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+class _LIBCPP_TYPE_VIS __codecvt_utf8<wchar_t>
+    : public codecvt<wchar_t, char, mbstate_t>
+{
+    unsigned long _Maxcode_;
+    codecvt_mode _Mode_;
+public:
+    typedef wchar_t   intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __codecvt_utf8(size_t __refs, unsigned long _Maxcode,
+                            codecvt_mode _Mode)
+        : codecvt<wchar_t, char, mbstate_t>(__refs), _Maxcode_(_Maxcode),
+          _Mode_(_Mode) {}
+protected:
+    virtual result
+        do_out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result
+        do_in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result
+        do_unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const _NOEXCEPT;
+    virtual bool do_always_noconv() const _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end,
+                          size_t __mx) const;
+    virtual int do_max_length() const _NOEXCEPT;
+};
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+class _LIBCPP_TYPE_VIS __codecvt_utf8<char16_t>
+    : public codecvt<char16_t, char, mbstate_t>
+{
+    unsigned long _Maxcode_;
+    codecvt_mode _Mode_;
+public:
+    typedef char16_t  intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __codecvt_utf8(size_t __refs, unsigned long _Maxcode,
+                            codecvt_mode _Mode)
+        : codecvt<char16_t, char, mbstate_t>(__refs), _Maxcode_(_Maxcode),
+          _Mode_(_Mode) {}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+protected:
+    virtual result
+        do_out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result
+        do_in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result
+        do_unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const _NOEXCEPT;
+    virtual bool do_always_noconv() const _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end,
+                          size_t __mx) const;
+    virtual int do_max_length() const _NOEXCEPT;
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+class _LIBCPP_TYPE_VIS __codecvt_utf8<char32_t>
+    : public codecvt<char32_t, char, mbstate_t>
+{
+    unsigned long _Maxcode_;
+    codecvt_mode _Mode_;
+public:
+    typedef char32_t  intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __codecvt_utf8(size_t __refs, unsigned long _Maxcode,
+                            codecvt_mode _Mode)
+        : codecvt<char32_t, char, mbstate_t>(__refs), _Maxcode_(_Maxcode),
+          _Mode_(_Mode) {}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+protected:
+    virtual result
+        do_out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result
+        do_in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result
+        do_unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const _NOEXCEPT;
+    virtual bool do_always_noconv() const _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end,
+                          size_t __mx) const;
+    virtual int do_max_length() const _NOEXCEPT;
+};
+
+template <class _Elem, unsigned long _Maxcode = 0x10ffff,
+          codecvt_mode _Mode = (codecvt_mode)0>
+class _LIBCPP_TEMPLATE_VIS codecvt_utf8
+    : public __codecvt_utf8<_Elem>
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt_utf8(size_t __refs = 0)
+        : __codecvt_utf8<_Elem>(__refs, _Maxcode, _Mode) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~codecvt_utf8() {}
+};
+
+// codecvt_utf16
+
+template <class _Elem, bool _LittleEndian> class __codecvt_utf16;
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+class _LIBCPP_TYPE_VIS __codecvt_utf16<wchar_t, false>
+    : public codecvt<wchar_t, char, mbstate_t>
+{
+    unsigned long _Maxcode_;
+    codecvt_mode _Mode_;
+public:
+    typedef wchar_t   intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __codecvt_utf16(size_t __refs, unsigned long _Maxcode,
+                            codecvt_mode _Mode)
+        : codecvt<wchar_t, char, mbstate_t>(__refs), _Maxcode_(_Maxcode),
+          _Mode_(_Mode) {}
+protected:
+    virtual result
+        do_out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result
+        do_in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result
+        do_unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const _NOEXCEPT;
+    virtual bool do_always_noconv() const _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end,
+                          size_t __mx) const;
+    virtual int do_max_length() const _NOEXCEPT;
+};
+
+template <>
+class _LIBCPP_TYPE_VIS __codecvt_utf16<wchar_t, true>
+    : public codecvt<wchar_t, char, mbstate_t>
+{
+    unsigned long _Maxcode_;
+    codecvt_mode _Mode_;
+public:
+    typedef wchar_t   intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __codecvt_utf16(size_t __refs, unsigned long _Maxcode,
+                            codecvt_mode _Mode)
+        : codecvt<wchar_t, char, mbstate_t>(__refs), _Maxcode_(_Maxcode),
+          _Mode_(_Mode) {}
+protected:
+    virtual result
+        do_out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result
+        do_in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result
+        do_unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const _NOEXCEPT;
+    virtual bool do_always_noconv() const _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end,
+                          size_t __mx) const;
+    virtual int do_max_length() const _NOEXCEPT;
+};
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+class _LIBCPP_TYPE_VIS __codecvt_utf16<char16_t, false>
+    : public codecvt<char16_t, char, mbstate_t>
+{
+    unsigned long _Maxcode_;
+    codecvt_mode _Mode_;
+public:
+    typedef char16_t  intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __codecvt_utf16(size_t __refs, unsigned long _Maxcode,
+                            codecvt_mode _Mode)
+        : codecvt<char16_t, char, mbstate_t>(__refs), _Maxcode_(_Maxcode),
+          _Mode_(_Mode) {}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+protected:
+    virtual result
+        do_out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result
+        do_in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result
+        do_unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const _NOEXCEPT;
+    virtual bool do_always_noconv() const _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end,
+                          size_t __mx) const;
+    virtual int do_max_length() const _NOEXCEPT;
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+class _LIBCPP_TYPE_VIS __codecvt_utf16<char16_t, true>
+    : public codecvt<char16_t, char, mbstate_t>
+{
+    unsigned long _Maxcode_;
+    codecvt_mode _Mode_;
+public:
+    typedef char16_t  intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __codecvt_utf16(size_t __refs, unsigned long _Maxcode,
+                            codecvt_mode _Mode)
+        : codecvt<char16_t, char, mbstate_t>(__refs), _Maxcode_(_Maxcode),
+          _Mode_(_Mode) {}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+protected:
+    virtual result
+        do_out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result
+        do_in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result
+        do_unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const _NOEXCEPT;
+    virtual bool do_always_noconv() const _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end,
+                          size_t __mx) const;
+    virtual int do_max_length() const _NOEXCEPT;
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+class _LIBCPP_TYPE_VIS __codecvt_utf16<char32_t, false>
+    : public codecvt<char32_t, char, mbstate_t>
+{
+    unsigned long _Maxcode_;
+    codecvt_mode _Mode_;
+public:
+    typedef char32_t  intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __codecvt_utf16(size_t __refs, unsigned long _Maxcode,
+                            codecvt_mode _Mode)
+        : codecvt<char32_t, char, mbstate_t>(__refs), _Maxcode_(_Maxcode),
+          _Mode_(_Mode) {}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+protected:
+    virtual result
+        do_out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result
+        do_in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result
+        do_unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const _NOEXCEPT;
+    virtual bool do_always_noconv() const _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end,
+                          size_t __mx) const;
+    virtual int do_max_length() const _NOEXCEPT;
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+class _LIBCPP_TYPE_VIS __codecvt_utf16<char32_t, true>
+    : public codecvt<char32_t, char, mbstate_t>
+{
+    unsigned long _Maxcode_;
+    codecvt_mode _Mode_;
+public:
+    typedef char32_t  intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __codecvt_utf16(size_t __refs, unsigned long _Maxcode,
+                            codecvt_mode _Mode)
+        : codecvt<char32_t, char, mbstate_t>(__refs), _Maxcode_(_Maxcode),
+          _Mode_(_Mode) {}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+protected:
+    virtual result
+        do_out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result
+        do_in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result
+        do_unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const _NOEXCEPT;
+    virtual bool do_always_noconv() const _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end,
+                          size_t __mx) const;
+    virtual int do_max_length() const _NOEXCEPT;
+};
+
+template <class _Elem, unsigned long _Maxcode = 0x10ffff,
+          codecvt_mode _Mode = (codecvt_mode)0>
+class _LIBCPP_TEMPLATE_VIS codecvt_utf16
+    : public __codecvt_utf16<_Elem, _Mode & little_endian>
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt_utf16(size_t __refs = 0)
+        : __codecvt_utf16<_Elem, _Mode & little_endian>(__refs, _Maxcode, _Mode) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~codecvt_utf16() {}
+};
+
+// codecvt_utf8_utf16
+
+template <class _Elem> class __codecvt_utf8_utf16;
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+class _LIBCPP_TYPE_VIS __codecvt_utf8_utf16<wchar_t>
+    : public codecvt<wchar_t, char, mbstate_t>
+{
+    unsigned long _Maxcode_;
+    codecvt_mode _Mode_;
+public:
+    typedef wchar_t   intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __codecvt_utf8_utf16(size_t __refs, unsigned long _Maxcode,
+                            codecvt_mode _Mode)
+        : codecvt<wchar_t, char, mbstate_t>(__refs), _Maxcode_(_Maxcode),
+          _Mode_(_Mode) {}
+protected:
+    virtual result
+        do_out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result
+        do_in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result
+        do_unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const _NOEXCEPT;
+    virtual bool do_always_noconv() const _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end,
+                          size_t __mx) const;
+    virtual int do_max_length() const _NOEXCEPT;
+};
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+class _LIBCPP_TYPE_VIS __codecvt_utf8_utf16<char32_t>
+    : public codecvt<char32_t, char, mbstate_t>
+{
+    unsigned long _Maxcode_;
+    codecvt_mode _Mode_;
+public:
+    typedef char32_t  intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __codecvt_utf8_utf16(size_t __refs, unsigned long _Maxcode,
+                            codecvt_mode _Mode)
+        : codecvt<char32_t, char, mbstate_t>(__refs), _Maxcode_(_Maxcode),
+          _Mode_(_Mode) {}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+protected:
+    virtual result
+        do_out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result
+        do_in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result
+        do_unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const _NOEXCEPT;
+    virtual bool do_always_noconv() const _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end,
+                          size_t __mx) const;
+    virtual int do_max_length() const _NOEXCEPT;
+};
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+template <>
+class _LIBCPP_TYPE_VIS __codecvt_utf8_utf16<char16_t>
+    : public codecvt<char16_t, char, mbstate_t>
+{
+    unsigned long _Maxcode_;
+    codecvt_mode _Mode_;
+public:
+    typedef char16_t  intern_type;
+    typedef char      extern_type;
+    typedef mbstate_t state_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __codecvt_utf8_utf16(size_t __refs, unsigned long _Maxcode,
+                            codecvt_mode _Mode)
+        : codecvt<char16_t, char, mbstate_t>(__refs), _Maxcode_(_Maxcode),
+          _Mode_(_Mode) {}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+protected:
+    virtual result
+        do_out(state_type& __st,
+               const intern_type* __frm, const intern_type* __frm_end, const intern_type*& __frm_nxt,
+               extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual result
+        do_in(state_type& __st,
+              const extern_type* __frm, const extern_type* __frm_end, const extern_type*& __frm_nxt,
+              intern_type* __to, intern_type* __to_end, intern_type*& __to_nxt) const;
+    virtual result
+        do_unshift(state_type& __st,
+                   extern_type* __to, extern_type* __to_end, extern_type*& __to_nxt) const;
+    virtual int do_encoding() const _NOEXCEPT;
+    virtual bool do_always_noconv() const _NOEXCEPT;
+    virtual int do_length(state_type&, const extern_type* __frm, const extern_type* __end,
+                          size_t __mx) const;
+    virtual int do_max_length() const _NOEXCEPT;
+};
+
+template <class _Elem, unsigned long _Maxcode = 0x10ffff,
+          codecvt_mode _Mode = (codecvt_mode)0>
+class _LIBCPP_TEMPLATE_VIS codecvt_utf8_utf16
+    : public __codecvt_utf8_utf16<_Elem>
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit codecvt_utf8_utf16(size_t __refs = 0)
+        : __codecvt_utf8_utf16<_Elem>(__refs, _Maxcode, _Mode) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~codecvt_utf8_utf16() {}
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CODECVT
diff --git a/contrib/libs/cxxsupp/libcxx/include/compare b/contrib/libs/cxxsupp/libcxx/include/compare
new file mode 100644
index 00000000000..ddb83135475
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/compare
@@ -0,0 +1,164 @@
+// -*- C++ -*-
+//===-------------------------- compare -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_COMPARE
+#define _LIBCPP_COMPARE
+
+/*
+    compare synopsis
+
+namespace std {
+  // [cmp.categories], comparison category types
+  class partial_ordering;
+  class weak_ordering;
+  class strong_ordering;
+
+  // named comparison functions
+  constexpr bool is_eq  (partial_ordering cmp) noexcept { return cmp == 0; }
+  constexpr bool is_neq (partial_ordering cmp) noexcept { return cmp != 0; }
+  constexpr bool is_lt  (partial_ordering cmp) noexcept { return cmp < 0; }
+  constexpr bool is_lteq(partial_ordering cmp) noexcept { return cmp <= 0; }
+  constexpr bool is_gt  (partial_ordering cmp) noexcept { return cmp > 0; }
+  constexpr bool is_gteq(partial_ordering cmp) noexcept { return cmp >= 0; }
+
+  // [cmp.common], common comparison category type
+  template<class... Ts>
+  struct common_comparison_category {
+    using type = see below;
+  };
+  template<class... Ts>
+    using common_comparison_category_t = typename common_comparison_category<Ts...>::type;
+
+  // [cmp.concept], concept three_way_comparable
+  template<class T, class Cat = partial_ordering>
+    concept three_way_comparable = see below;
+  template<class T, class U, class Cat = partial_ordering>
+    concept three_way_comparable_with = see below;
+
+  // [cmp.result], result of three-way comparison
+  template<class T, class U = T> struct compare_three_way_result;
+
+  template<class T, class U = T>
+    using compare_three_way_result_t = typename compare_three_way_result<T, U>::type;
+
+  // [comparisons.three.way], class compare_three_way
+  struct compare_three_way; // C++20
+
+  // [cmp.alg], comparison algorithms
+  template<class T> constexpr strong_ordering strong_order(const T& a, const T& b);
+  template<class T> constexpr weak_ordering weak_order(const T& a, const T& b);
+  template<class T> constexpr partial_ordering partial_order(const T& a, const T& b);
+
+  // [cmp.partialord], Class partial_ordering
+  class partial_ordering {
+  public:
+    // valid values
+    static const partial_ordering less;
+    static const partial_ordering equivalent;
+    static const partial_ordering greater;
+    static const partial_ordering unordered;
+
+    // comparisons
+    friend constexpr bool operator==(partial_ordering v, unspecified) noexcept;
+    friend constexpr bool operator==(partial_ordering v, partial_ordering w) noexcept = default;
+    friend constexpr bool operator< (partial_ordering v, unspecified) noexcept;
+    friend constexpr bool operator> (partial_ordering v, unspecified) noexcept;
+    friend constexpr bool operator<=(partial_ordering v, unspecified) noexcept;
+    friend constexpr bool operator>=(partial_ordering v, unspecified) noexcept;
+    friend constexpr bool operator< (unspecified, partial_ordering v) noexcept;
+    friend constexpr bool operator> (unspecified, partial_ordering v) noexcept;
+    friend constexpr bool operator<=(unspecified, partial_ordering v) noexcept;
+    friend constexpr bool operator>=(unspecified, partial_ordering v) noexcept;
+    friend constexpr partial_ordering operator<=>(partial_ordering v, unspecified) noexcept;
+    friend constexpr partial_ordering operator<=>(unspecified, partial_ordering v) noexcept;
+  };
+
+  // [cmp.weakord], Class weak_ordering
+  class weak_ordering {
+  public:
+    // valid values
+    static const weak_ordering less;
+    static const weak_ordering equivalent;
+    static const weak_ordering greater;
+
+    // conversions
+    constexpr operator partial_ordering() const noexcept;
+
+    // comparisons
+    friend constexpr bool operator==(weak_ordering v, unspecified) noexcept;
+    friend constexpr bool operator==(weak_ordering v, weak_ordering w) noexcept = default;
+    friend constexpr bool operator< (weak_ordering v, unspecified) noexcept;
+    friend constexpr bool operator> (weak_ordering v, unspecified) noexcept;
+    friend constexpr bool operator<=(weak_ordering v, unspecified) noexcept;
+    friend constexpr bool operator>=(weak_ordering v, unspecified) noexcept;
+    friend constexpr bool operator< (unspecified, weak_ordering v) noexcept;
+    friend constexpr bool operator> (unspecified, weak_ordering v) noexcept;
+    friend constexpr bool operator<=(unspecified, weak_ordering v) noexcept;
+    friend constexpr bool operator>=(unspecified, weak_ordering v) noexcept;
+    friend constexpr weak_ordering operator<=>(weak_ordering v, unspecified) noexcept;
+    friend constexpr weak_ordering operator<=>(unspecified, weak_ordering v) noexcept;
+  };
+
+  // [cmp.strongord], Class strong_ordering
+  class strong_ordering {
+  public:
+    // valid values
+    static const strong_ordering less;
+    static const strong_ordering equal;
+    static const strong_ordering equivalent;
+    static const strong_ordering greater;
+
+    // conversions
+    constexpr operator partial_ordering() const noexcept;
+    constexpr operator weak_ordering() const noexcept;
+
+    // comparisons
+    friend constexpr bool operator==(strong_ordering v, unspecified) noexcept;
+    friend constexpr bool operator==(strong_ordering v, strong_ordering w) noexcept = default;
+    friend constexpr bool operator< (strong_ordering v, unspecified) noexcept;
+    friend constexpr bool operator> (strong_ordering v, unspecified) noexcept;
+    friend constexpr bool operator<=(strong_ordering v, unspecified) noexcept;
+    friend constexpr bool operator>=(strong_ordering v, unspecified) noexcept;
+    friend constexpr bool operator< (unspecified, strong_ordering v) noexcept;
+    friend constexpr bool operator> (unspecified, strong_ordering v) noexcept;
+    friend constexpr bool operator<=(unspecified, strong_ordering v) noexcept;
+    friend constexpr bool operator>=(unspecified, strong_ordering v) noexcept;
+    friend constexpr strong_ordering operator<=>(strong_ordering v, unspecified) noexcept;
+    friend constexpr strong_ordering operator<=>(unspecified, strong_ordering v) noexcept;
+  };
+}
+*/
+
+#include <__compare/common_comparison_category.h>
+#include <__compare/compare_three_way.h>
+#include <__compare/compare_three_way_result.h>
+#include <__compare/is_eq.h>
+#include <__compare/ordering.h>
+#include <__compare/three_way_comparable.h>
+#include <__config>
+
+#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR)
+
+// [cmp.alg], comparison algorithms
+// TODO: unimplemented
+template<class _Tp> constexpr strong_ordering strong_order(const _Tp& __lhs, const _Tp& __rhs);
+template<class _Tp> constexpr weak_ordering weak_order(const _Tp& __lhs, const _Tp& __rhs);
+template<class _Tp> constexpr partial_ordering partial_order(const _Tp& __lhs, const _Tp& __rhs);
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_COMPARE
diff --git a/contrib/libs/cxxsupp/libcxx/include/complex b/contrib/libs/cxxsupp/libcxx/include/complex
new file mode 100644
index 00000000000..e4c59193bce
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/complex
@@ -0,0 +1,1495 @@
+// -*- C++ -*-
+//===--------------------------- complex ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_COMPLEX
+#define _LIBCPP_COMPLEX
+
+/*
+    complex synopsis
+
+namespace std
+{
+
+template<class T>
+class complex
+{
+public:
+    typedef T value_type;
+
+    complex(const T& re = T(), const T& im = T()); // constexpr in C++14
+    complex(const complex&);  // constexpr in C++14
+    template<class X> complex(const complex<X>&);  // constexpr in C++14
+
+    T real() const; // constexpr in C++14
+    T imag() const; // constexpr in C++14
+
+    void real(T);
+    void imag(T);
+
+    complex<T>& operator= (const T&);
+    complex<T>& operator+=(const T&);
+    complex<T>& operator-=(const T&);
+    complex<T>& operator*=(const T&);
+    complex<T>& operator/=(const T&);
+
+    complex& operator=(const complex&);
+    template<class X> complex<T>& operator= (const complex<X>&);
+    template<class X> complex<T>& operator+=(const complex<X>&);
+    template<class X> complex<T>& operator-=(const complex<X>&);
+    template<class X> complex<T>& operator*=(const complex<X>&);
+    template<class X> complex<T>& operator/=(const complex<X>&);
+};
+
+template<>
+class complex<float>
+{
+public:
+    typedef float value_type;
+
+    constexpr complex(float re = 0.0f, float im = 0.0f);
+    explicit constexpr complex(const complex<double>&);
+    explicit constexpr complex(const complex<long double>&);
+
+    constexpr float real() const;
+    void real(float);
+    constexpr float imag() const;
+    void imag(float);
+
+    complex<float>& operator= (float);
+    complex<float>& operator+=(float);
+    complex<float>& operator-=(float);
+    complex<float>& operator*=(float);
+    complex<float>& operator/=(float);
+
+    complex<float>& operator=(const complex<float>&);
+    template<class X> complex<float>& operator= (const complex<X>&);
+    template<class X> complex<float>& operator+=(const complex<X>&);
+    template<class X> complex<float>& operator-=(const complex<X>&);
+    template<class X> complex<float>& operator*=(const complex<X>&);
+    template<class X> complex<float>& operator/=(const complex<X>&);
+};
+
+template<>
+class complex<double>
+{
+public:
+    typedef double value_type;
+
+    constexpr complex(double re = 0.0, double im = 0.0);
+    constexpr complex(const complex<float>&);
+    explicit constexpr complex(const complex<long double>&);
+
+    constexpr double real() const;
+    void real(double);
+    constexpr double imag() const;
+    void imag(double);
+
+    complex<double>& operator= (double);
+    complex<double>& operator+=(double);
+    complex<double>& operator-=(double);
+    complex<double>& operator*=(double);
+    complex<double>& operator/=(double);
+    complex<double>& operator=(const complex<double>&);
+
+    template<class X> complex<double>& operator= (const complex<X>&);
+    template<class X> complex<double>& operator+=(const complex<X>&);
+    template<class X> complex<double>& operator-=(const complex<X>&);
+    template<class X> complex<double>& operator*=(const complex<X>&);
+    template<class X> complex<double>& operator/=(const complex<X>&);
+};
+
+template<>
+class complex<long double>
+{
+public:
+    typedef long double value_type;
+
+    constexpr complex(long double re = 0.0L, long double im = 0.0L);
+    constexpr complex(const complex<float>&);
+    constexpr complex(const complex<double>&);
+
+    constexpr long double real() const;
+    void real(long double);
+    constexpr long double imag() const;
+    void imag(long double);
+
+    complex<long double>& operator=(const complex<long double>&);
+    complex<long double>& operator= (long double);
+    complex<long double>& operator+=(long double);
+    complex<long double>& operator-=(long double);
+    complex<long double>& operator*=(long double);
+    complex<long double>& operator/=(long double);
+
+    template<class X> complex<long double>& operator= (const complex<X>&);
+    template<class X> complex<long double>& operator+=(const complex<X>&);
+    template<class X> complex<long double>& operator-=(const complex<X>&);
+    template<class X> complex<long double>& operator*=(const complex<X>&);
+    template<class X> complex<long double>& operator/=(const complex<X>&);
+};
+
+// 26.3.6 operators:
+template<class T> complex<T> operator+(const complex<T>&, const complex<T>&);
+template<class T> complex<T> operator+(const complex<T>&, const T&);
+template<class T> complex<T> operator+(const T&, const complex<T>&);
+template<class T> complex<T> operator-(const complex<T>&, const complex<T>&);
+template<class T> complex<T> operator-(const complex<T>&, const T&);
+template<class T> complex<T> operator-(const T&, const complex<T>&);
+template<class T> complex<T> operator*(const complex<T>&, const complex<T>&);
+template<class T> complex<T> operator*(const complex<T>&, const T&);
+template<class T> complex<T> operator*(const T&, const complex<T>&);
+template<class T> complex<T> operator/(const complex<T>&, const complex<T>&);
+template<class T> complex<T> operator/(const complex<T>&, const T&);
+template<class T> complex<T> operator/(const T&, const complex<T>&);
+template<class T> complex<T> operator+(const complex<T>&);
+template<class T> complex<T> operator-(const complex<T>&);
+template<class T> bool operator==(const complex<T>&, const complex<T>&); // constexpr in C++14
+template<class T> bool operator==(const complex<T>&, const T&); // constexpr in C++14
+template<class T> bool operator==(const T&, const complex<T>&); // constexpr in C++14
+template<class T> bool operator!=(const complex<T>&, const complex<T>&); // constexpr in C++14
+template<class T> bool operator!=(const complex<T>&, const T&); // constexpr in C++14
+template<class T> bool operator!=(const T&, const complex<T>&); // constexpr in C++14
+
+template<class T, class charT, class traits>
+  basic_istream<charT, traits>&
+  operator>>(basic_istream<charT, traits>&, complex<T>&);
+template<class T, class charT, class traits>
+  basic_ostream<charT, traits>&
+  operator<<(basic_ostream<charT, traits>&, const complex<T>&);
+
+// 26.3.7 values:
+
+template<class T>              T real(const complex<T>&); // constexpr in C++14
+                     long double real(long double);       // constexpr in C++14
+                          double real(double);            // constexpr in C++14
+template<Integral T>      double real(T);                 // constexpr in C++14
+                          float  real(float);             // constexpr in C++14
+
+template<class T>              T imag(const complex<T>&); // constexpr in C++14
+                     long double imag(long double);       // constexpr in C++14
+                          double imag(double);            // constexpr in C++14
+template<Integral T>      double imag(T);                 // constexpr in C++14
+                          float  imag(float);             // constexpr in C++14
+
+template<class T> T abs(const complex<T>&);
+
+template<class T>              T arg(const complex<T>&);
+                     long double arg(long double);
+                          double arg(double);
+template<Integral T>      double arg(T);
+                          float  arg(float);
+
+template<class T>              T norm(const complex<T>&);
+                     long double norm(long double);
+                          double norm(double);
+template<Integral T>      double norm(T);
+                          float  norm(float);
+
+template<class T>      complex<T>           conj(const complex<T>&);
+                       complex<long double> conj(long double);
+                       complex<double>      conj(double);
+template<Integral T>   complex<double>      conj(T);
+                       complex<float>       conj(float);
+
+template<class T>    complex<T>           proj(const complex<T>&);
+                     complex<long double> proj(long double);
+                     complex<double>      proj(double);
+template<Integral T> complex<double>      proj(T);
+                     complex<float>       proj(float);
+
+template<class T> complex<T> polar(const T&, const T& = T());
+
+// 26.3.8 transcendentals:
+template<class T> complex<T> acos(const complex<T>&);
+template<class T> complex<T> asin(const complex<T>&);
+template<class T> complex<T> atan(const complex<T>&);
+template<class T> complex<T> acosh(const complex<T>&);
+template<class T> complex<T> asinh(const complex<T>&);
+template<class T> complex<T> atanh(const complex<T>&);
+template<class T> complex<T> cos (const complex<T>&);
+template<class T> complex<T> cosh (const complex<T>&);
+template<class T> complex<T> exp (const complex<T>&);
+template<class T> complex<T> log (const complex<T>&);
+template<class T> complex<T> log10(const complex<T>&);
+
+template<class T> complex<T> pow(const complex<T>&, const T&);
+template<class T> complex<T> pow(const complex<T>&, const complex<T>&);
+template<class T> complex<T> pow(const T&, const complex<T>&);
+
+template<class T> complex<T> sin (const complex<T>&);
+template<class T> complex<T> sinh (const complex<T>&);
+template<class T> complex<T> sqrt (const complex<T>&);
+template<class T> complex<T> tan (const complex<T>&);
+template<class T> complex<T> tanh (const complex<T>&);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <cmath>
+#include <iosfwd>
+#include <stdexcept>
+#include <type_traits>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#   include <sstream> // for std::basic_ostringstream
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _Tp> class _LIBCPP_TEMPLATE_VIS complex;
+
+template<class _Tp> complex<_Tp> operator*(const complex<_Tp>& __z, const complex<_Tp>& __w);
+template<class _Tp> complex<_Tp> operator/(const complex<_Tp>& __x, const complex<_Tp>& __y);
+
+template<class _Tp>
+class _LIBCPP_TEMPLATE_VIS complex
+{
+public:
+    typedef _Tp value_type;
+private:
+    value_type __re_;
+    value_type __im_;
+public:
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    complex(const value_type& __re = value_type(), const value_type& __im = value_type())
+        : __re_(__re), __im_(__im) {}
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    complex(const complex<_Xp>& __c)
+        : __re_(__c.real()), __im_(__c.imag()) {}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 value_type real() const {return __re_;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 value_type imag() const {return __im_;}
+
+    _LIBCPP_INLINE_VISIBILITY void real(value_type __re) {__re_ = __re;}
+    _LIBCPP_INLINE_VISIBILITY void imag(value_type __im) {__im_ = __im;}
+
+    _LIBCPP_INLINE_VISIBILITY complex& operator= (const value_type& __re)
+        {__re_ = __re; __im_ = value_type(); return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator+=(const value_type& __re) {__re_ += __re; return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator-=(const value_type& __re) {__re_ -= __re; return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator*=(const value_type& __re) {__re_ *= __re; __im_ *= __re; return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator/=(const value_type& __re) {__re_ /= __re; __im_ /= __re; return *this;}
+
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator= (const complex<_Xp>& __c)
+        {
+            __re_ = __c.real();
+            __im_ = __c.imag();
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator+=(const complex<_Xp>& __c)
+        {
+            __re_ += __c.real();
+            __im_ += __c.imag();
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator-=(const complex<_Xp>& __c)
+        {
+            __re_ -= __c.real();
+            __im_ -= __c.imag();
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator*=(const complex<_Xp>& __c)
+        {
+            *this = *this * complex(__c.real(), __c.imag());
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator/=(const complex<_Xp>& __c)
+        {
+            *this = *this / complex(__c.real(), __c.imag());
+            return *this;
+        }
+};
+
+template<> class _LIBCPP_TEMPLATE_VIS complex<double>;
+template<> class _LIBCPP_TEMPLATE_VIS complex<long double>;
+
+template<>
+class _LIBCPP_TEMPLATE_VIS complex<float>
+{
+    float __re_;
+    float __im_;
+public:
+    typedef float value_type;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR complex(float __re = 0.0f, float __im = 0.0f)
+        : __re_(__re), __im_(__im) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit _LIBCPP_CONSTEXPR complex(const complex<double>& __c);
+    _LIBCPP_INLINE_VISIBILITY
+    explicit _LIBCPP_CONSTEXPR complex(const complex<long double>& __c);
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR float real() const {return __re_;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR float imag() const {return __im_;}
+
+    _LIBCPP_INLINE_VISIBILITY void real(value_type __re) {__re_ = __re;}
+    _LIBCPP_INLINE_VISIBILITY void imag(value_type __im) {__im_ = __im;}
+
+    _LIBCPP_INLINE_VISIBILITY complex& operator= (float __re)
+        {__re_ = __re; __im_ = value_type(); return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator+=(float __re) {__re_ += __re; return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator-=(float __re) {__re_ -= __re; return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator*=(float __re) {__re_ *= __re; __im_ *= __re; return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator/=(float __re) {__re_ /= __re; __im_ /= __re; return *this;}
+
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator= (const complex<_Xp>& __c)
+        {
+            __re_ = __c.real();
+            __im_ = __c.imag();
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator+=(const complex<_Xp>& __c)
+        {
+            __re_ += __c.real();
+            __im_ += __c.imag();
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator-=(const complex<_Xp>& __c)
+        {
+            __re_ -= __c.real();
+            __im_ -= __c.imag();
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator*=(const complex<_Xp>& __c)
+        {
+            *this = *this * complex(__c.real(), __c.imag());
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator/=(const complex<_Xp>& __c)
+        {
+            *this = *this / complex(__c.real(), __c.imag());
+            return *this;
+        }
+};
+
+template<>
+class _LIBCPP_TEMPLATE_VIS complex<double>
+{
+    double __re_;
+    double __im_;
+public:
+    typedef double value_type;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR complex(double __re = 0.0, double __im = 0.0)
+        : __re_(__re), __im_(__im) {}
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR complex(const complex<float>& __c);
+    _LIBCPP_INLINE_VISIBILITY
+    explicit _LIBCPP_CONSTEXPR complex(const complex<long double>& __c);
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR double real() const {return __re_;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR double imag() const {return __im_;}
+
+    _LIBCPP_INLINE_VISIBILITY void real(value_type __re) {__re_ = __re;}
+    _LIBCPP_INLINE_VISIBILITY void imag(value_type __im) {__im_ = __im;}
+
+    _LIBCPP_INLINE_VISIBILITY complex& operator= (double __re)
+        {__re_ = __re; __im_ = value_type(); return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator+=(double __re) {__re_ += __re; return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator-=(double __re) {__re_ -= __re; return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator*=(double __re) {__re_ *= __re; __im_ *= __re; return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator/=(double __re) {__re_ /= __re; __im_ /= __re; return *this;}
+
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator= (const complex<_Xp>& __c)
+        {
+            __re_ = __c.real();
+            __im_ = __c.imag();
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator+=(const complex<_Xp>& __c)
+        {
+            __re_ += __c.real();
+            __im_ += __c.imag();
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator-=(const complex<_Xp>& __c)
+        {
+            __re_ -= __c.real();
+            __im_ -= __c.imag();
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator*=(const complex<_Xp>& __c)
+        {
+            *this = *this * complex(__c.real(), __c.imag());
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator/=(const complex<_Xp>& __c)
+        {
+            *this = *this / complex(__c.real(), __c.imag());
+            return *this;
+        }
+};
+
+template<>
+class _LIBCPP_TEMPLATE_VIS complex<long double>
+{
+    long double __re_;
+    long double __im_;
+public:
+    typedef long double value_type;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR complex(long double __re = 0.0L, long double __im = 0.0L)
+        : __re_(__re), __im_(__im) {}
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR complex(const complex<float>& __c);
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR complex(const complex<double>& __c);
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR long double real() const {return __re_;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR long double imag() const {return __im_;}
+
+    _LIBCPP_INLINE_VISIBILITY void real(value_type __re) {__re_ = __re;}
+    _LIBCPP_INLINE_VISIBILITY void imag(value_type __im) {__im_ = __im;}
+
+    _LIBCPP_INLINE_VISIBILITY complex& operator= (long double __re)
+        {__re_ = __re; __im_ = value_type(); return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator+=(long double __re) {__re_ += __re; return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator-=(long double __re) {__re_ -= __re; return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator*=(long double __re) {__re_ *= __re; __im_ *= __re; return *this;}
+    _LIBCPP_INLINE_VISIBILITY complex& operator/=(long double __re) {__re_ /= __re; __im_ /= __re; return *this;}
+
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator= (const complex<_Xp>& __c)
+        {
+            __re_ = __c.real();
+            __im_ = __c.imag();
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator+=(const complex<_Xp>& __c)
+        {
+            __re_ += __c.real();
+            __im_ += __c.imag();
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator-=(const complex<_Xp>& __c)
+        {
+            __re_ -= __c.real();
+            __im_ -= __c.imag();
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator*=(const complex<_Xp>& __c)
+        {
+            *this = *this * complex(__c.real(), __c.imag());
+            return *this;
+        }
+    template<class _Xp> _LIBCPP_INLINE_VISIBILITY complex& operator/=(const complex<_Xp>& __c)
+        {
+            *this = *this / complex(__c.real(), __c.imag());
+            return *this;
+        }
+};
+
+inline
+_LIBCPP_CONSTEXPR
+complex<float>::complex(const complex<double>& __c)
+    : __re_(__c.real()), __im_(__c.imag()) {}
+
+inline
+_LIBCPP_CONSTEXPR
+complex<float>::complex(const complex<long double>& __c)
+    : __re_(__c.real()), __im_(__c.imag()) {}
+
+inline
+_LIBCPP_CONSTEXPR
+complex<double>::complex(const complex<float>& __c)
+    : __re_(__c.real()), __im_(__c.imag()) {}
+
+inline
+_LIBCPP_CONSTEXPR
+complex<double>::complex(const complex<long double>& __c)
+    : __re_(__c.real()), __im_(__c.imag()) {}
+
+inline
+_LIBCPP_CONSTEXPR
+complex<long double>::complex(const complex<float>& __c)
+    : __re_(__c.real()), __im_(__c.imag()) {}
+
+inline
+_LIBCPP_CONSTEXPR
+complex<long double>::complex(const complex<double>& __c)
+    : __re_(__c.real()), __im_(__c.imag()) {}
+
+// 26.3.6 operators:
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+operator+(const complex<_Tp>& __x, const complex<_Tp>& __y)
+{
+    complex<_Tp> __t(__x);
+    __t += __y;
+    return __t;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+operator+(const complex<_Tp>& __x, const _Tp& __y)
+{
+    complex<_Tp> __t(__x);
+    __t += __y;
+    return __t;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+operator+(const _Tp& __x, const complex<_Tp>& __y)
+{
+    complex<_Tp> __t(__y);
+    __t += __x;
+    return __t;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+operator-(const complex<_Tp>& __x, const complex<_Tp>& __y)
+{
+    complex<_Tp> __t(__x);
+    __t -= __y;
+    return __t;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+operator-(const complex<_Tp>& __x, const _Tp& __y)
+{
+    complex<_Tp> __t(__x);
+    __t -= __y;
+    return __t;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+operator-(const _Tp& __x, const complex<_Tp>& __y)
+{
+    complex<_Tp> __t(-__y);
+    __t += __x;
+    return __t;
+}
+
+template<class _Tp>
+complex<_Tp>
+operator*(const complex<_Tp>& __z, const complex<_Tp>& __w)
+{
+    _Tp __a = __z.real();
+    _Tp __b = __z.imag();
+    _Tp __c = __w.real();
+    _Tp __d = __w.imag();
+    _Tp __ac = __a * __c;
+    _Tp __bd = __b * __d;
+    _Tp __ad = __a * __d;
+    _Tp __bc = __b * __c;
+    _Tp __x = __ac - __bd;
+    _Tp __y = __ad + __bc;
+    if (__libcpp_isnan_or_builtin(__x) && __libcpp_isnan_or_builtin(__y))
+    {
+        bool __recalc = false;
+        if (__libcpp_isinf_or_builtin(__a) || __libcpp_isinf_or_builtin(__b))
+        {
+            __a = copysign(__libcpp_isinf_or_builtin(__a) ? _Tp(1) : _Tp(0), __a);
+            __b = copysign(__libcpp_isinf_or_builtin(__b) ? _Tp(1) : _Tp(0), __b);
+            if (__libcpp_isnan_or_builtin(__c))
+                __c = copysign(_Tp(0), __c);
+            if (__libcpp_isnan_or_builtin(__d))
+                __d = copysign(_Tp(0), __d);
+            __recalc = true;
+        }
+        if (__libcpp_isinf_or_builtin(__c) || __libcpp_isinf_or_builtin(__d))
+        {
+            __c = copysign(__libcpp_isinf_or_builtin(__c) ? _Tp(1) : _Tp(0), __c);
+            __d = copysign(__libcpp_isinf_or_builtin(__d) ? _Tp(1) : _Tp(0), __d);
+            if (__libcpp_isnan_or_builtin(__a))
+                __a = copysign(_Tp(0), __a);
+            if (__libcpp_isnan_or_builtin(__b))
+                __b = copysign(_Tp(0), __b);
+            __recalc = true;
+        }
+        if (!__recalc && (__libcpp_isinf_or_builtin(__ac) || __libcpp_isinf_or_builtin(__bd) ||
+                          __libcpp_isinf_or_builtin(__ad) || __libcpp_isinf_or_builtin(__bc)))
+        {
+            if (__libcpp_isnan_or_builtin(__a))
+                __a = copysign(_Tp(0), __a);
+            if (__libcpp_isnan_or_builtin(__b))
+                __b = copysign(_Tp(0), __b);
+            if (__libcpp_isnan_or_builtin(__c))
+                __c = copysign(_Tp(0), __c);
+            if (__libcpp_isnan_or_builtin(__d))
+                __d = copysign(_Tp(0), __d);
+            __recalc = true;
+        }
+        if (__recalc)
+        {
+            __x = _Tp(INFINITY) * (__a * __c - __b * __d);
+            __y = _Tp(INFINITY) * (__a * __d + __b * __c);
+        }
+    }
+    return complex<_Tp>(__x, __y);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+operator*(const complex<_Tp>& __x, const _Tp& __y)
+{
+    complex<_Tp> __t(__x);
+    __t *= __y;
+    return __t;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+operator*(const _Tp& __x, const complex<_Tp>& __y)
+{
+    complex<_Tp> __t(__y);
+    __t *= __x;
+    return __t;
+}
+
+template<class _Tp>
+complex<_Tp>
+operator/(const complex<_Tp>& __z, const complex<_Tp>& __w)
+{
+    int __ilogbw = 0;
+    _Tp __a = __z.real();
+    _Tp __b = __z.imag();
+    _Tp __c = __w.real();
+    _Tp __d = __w.imag();
+    _Tp __logbw = logb(fmax(fabs(__c), fabs(__d)));
+    if (__libcpp_isfinite_or_builtin(__logbw))
+    {
+        __ilogbw = static_cast<int>(__logbw);
+        __c = scalbn(__c, -__ilogbw);
+        __d = scalbn(__d, -__ilogbw);
+    }
+    _Tp __denom = __c * __c + __d * __d;
+    _Tp __x = scalbn((__a * __c + __b * __d) / __denom, -__ilogbw);
+    _Tp __y = scalbn((__b * __c - __a * __d) / __denom, -__ilogbw);
+    if (__libcpp_isnan_or_builtin(__x) && __libcpp_isnan_or_builtin(__y))
+    {
+        if ((__denom == _Tp(0)) && (!__libcpp_isnan_or_builtin(__a) || !__libcpp_isnan_or_builtin(__b)))
+        {
+            __x = copysign(_Tp(INFINITY), __c) * __a;
+            __y = copysign(_Tp(INFINITY), __c) * __b;
+        }
+        else if ((__libcpp_isinf_or_builtin(__a) || __libcpp_isinf_or_builtin(__b)) && __libcpp_isfinite_or_builtin(__c) && __libcpp_isfinite_or_builtin(__d))
+        {
+            __a = copysign(__libcpp_isinf_or_builtin(__a) ? _Tp(1) : _Tp(0), __a);
+            __b = copysign(__libcpp_isinf_or_builtin(__b) ? _Tp(1) : _Tp(0), __b);
+            __x = _Tp(INFINITY) * (__a * __c + __b * __d);
+            __y = _Tp(INFINITY) * (__b * __c - __a * __d);
+        }
+        else if (__libcpp_isinf_or_builtin(__logbw) && __logbw > _Tp(0) && __libcpp_isfinite_or_builtin(__a) && __libcpp_isfinite_or_builtin(__b))
+        {
+            __c = copysign(__libcpp_isinf_or_builtin(__c) ? _Tp(1) : _Tp(0), __c);
+            __d = copysign(__libcpp_isinf_or_builtin(__d) ? _Tp(1) : _Tp(0), __d);
+            __x = _Tp(0) * (__a * __c + __b * __d);
+            __y = _Tp(0) * (__b * __c - __a * __d);
+        }
+    }
+    return complex<_Tp>(__x, __y);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+operator/(const complex<_Tp>& __x, const _Tp& __y)
+{
+    return complex<_Tp>(__x.real() / __y, __x.imag() / __y);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+operator/(const _Tp& __x, const complex<_Tp>& __y)
+{
+    complex<_Tp> __t(__x);
+    __t /= __y;
+    return __t;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+operator+(const complex<_Tp>& __x)
+{
+    return __x;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+operator-(const complex<_Tp>& __x)
+{
+    return complex<_Tp>(-__x.real(), -__x.imag());
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator==(const complex<_Tp>& __x, const complex<_Tp>& __y)
+{
+    return __x.real() == __y.real() && __x.imag() == __y.imag();
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator==(const complex<_Tp>& __x, const _Tp& __y)
+{
+    return __x.real() == __y && __x.imag() == 0;
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator==(const _Tp& __x, const complex<_Tp>& __y)
+{
+    return __x == __y.real() && 0 == __y.imag();
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator!=(const complex<_Tp>& __x, const complex<_Tp>& __y)
+{
+    return !(__x == __y);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator!=(const complex<_Tp>& __x, const _Tp& __y)
+{
+    return !(__x == __y);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator!=(const _Tp& __x, const complex<_Tp>& __y)
+{
+    return !(__x == __y);
+}
+
+// 26.3.7 values:
+
+template <class _Tp, bool = is_integral<_Tp>::value,
+                     bool = is_floating_point<_Tp>::value
+                     >
+struct __libcpp_complex_overload_traits {};
+
+// Integral Types
+template <class _Tp>
+struct __libcpp_complex_overload_traits<_Tp, true, false>
+{
+    typedef double _ValueType;
+    typedef complex<double> _ComplexType;
+};
+
+// Floating point types
+template <class _Tp>
+struct __libcpp_complex_overload_traits<_Tp, false, true>
+{
+    typedef _Tp _ValueType;
+    typedef complex<_Tp> _ComplexType;
+};
+
+// real
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp
+real(const complex<_Tp>& __c)
+{
+    return __c.real();
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename __libcpp_complex_overload_traits<_Tp>::_ValueType
+real(_Tp __re)
+{
+    return __re;
+}
+
+// imag
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+_Tp
+imag(const complex<_Tp>& __c)
+{
+    return __c.imag();
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename __libcpp_complex_overload_traits<_Tp>::_ValueType
+imag(_Tp)
+{
+    return 0;
+}
+
+// abs
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+abs(const complex<_Tp>& __c)
+{
+    return hypot(__c.real(), __c.imag());
+}
+
+// arg
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+arg(const complex<_Tp>& __c)
+{
+    return atan2(__c.imag(), __c.real());
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if<
+    is_same<_Tp, long double>::value,
+    long double
+>::type
+arg(_Tp __re)
+{
+    return atan2l(0.L, __re);
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value || is_same<_Tp, double>::value,
+    double
+>::type
+arg(_Tp __re)
+{
+    return atan2(0., __re);
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if<
+    is_same<_Tp, float>::value,
+    float
+>::type
+arg(_Tp __re)
+{
+    return atan2f(0.F, __re);
+}
+
+// norm
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp
+norm(const complex<_Tp>& __c)
+{
+    if (__libcpp_isinf_or_builtin(__c.real()))
+        return abs(__c.real());
+    if (__libcpp_isinf_or_builtin(__c.imag()))
+        return abs(__c.imag());
+    return __c.real() * __c.real() + __c.imag() * __c.imag();
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __libcpp_complex_overload_traits<_Tp>::_ValueType
+norm(_Tp __re)
+{
+    typedef typename __libcpp_complex_overload_traits<_Tp>::_ValueType _ValueType;
+    return static_cast<_ValueType>(__re) * __re;
+}
+
+// conj
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+conj(const complex<_Tp>& __c)
+{
+    return complex<_Tp>(__c.real(), -__c.imag());
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename __libcpp_complex_overload_traits<_Tp>::_ComplexType
+conj(_Tp __re)
+{
+    typedef typename __libcpp_complex_overload_traits<_Tp>::_ComplexType _ComplexType;
+    return _ComplexType(__re);
+}
+
+
+
+// proj
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+proj(const complex<_Tp>& __c)
+{
+    complex<_Tp> __r = __c;
+    if (__libcpp_isinf_or_builtin(__c.real()) || __libcpp_isinf_or_builtin(__c.imag()))
+        __r = complex<_Tp>(INFINITY, copysign(_Tp(0), __c.imag()));
+    return __r;
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_floating_point<_Tp>::value,
+    typename __libcpp_complex_overload_traits<_Tp>::_ComplexType
+>::type
+proj(_Tp __re)
+{
+    if (__libcpp_isinf_or_builtin(__re))
+        __re = abs(__re);
+    return complex<_Tp>(__re);
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_integral<_Tp>::value,
+    typename __libcpp_complex_overload_traits<_Tp>::_ComplexType
+>::type
+proj(_Tp __re)
+{
+    typedef typename __libcpp_complex_overload_traits<_Tp>::_ComplexType _ComplexType;
+    return _ComplexType(__re);
+}
+
+// polar
+
+template<class _Tp>
+complex<_Tp>
+polar(const _Tp& __rho, const _Tp& __theta = _Tp())
+{
+    if (__libcpp_isnan_or_builtin(__rho) || signbit(__rho))
+        return complex<_Tp>(_Tp(NAN), _Tp(NAN));
+    if (__libcpp_isnan_or_builtin(__theta))
+    {
+        if (__libcpp_isinf_or_builtin(__rho))
+            return complex<_Tp>(__rho, __theta);
+        return complex<_Tp>(__theta, __theta);
+    }
+    if (__libcpp_isinf_or_builtin(__theta))
+    {
+        if (__libcpp_isinf_or_builtin(__rho))
+            return complex<_Tp>(__rho, _Tp(NAN));
+        return complex<_Tp>(_Tp(NAN), _Tp(NAN));
+    }
+    _Tp __x = __rho * cos(__theta);
+    if (__libcpp_isnan_or_builtin(__x))
+        __x = 0;
+    _Tp __y = __rho * sin(__theta);
+    if (__libcpp_isnan_or_builtin(__y))
+        __y = 0;
+    return complex<_Tp>(__x, __y);
+}
+
+// log
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+log(const complex<_Tp>& __x)
+{
+    return complex<_Tp>(log(abs(__x)), arg(__x));
+}
+
+// log10
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+log10(const complex<_Tp>& __x)
+{
+    return log(__x) / log(_Tp(10));
+}
+
+// sqrt
+
+template<class _Tp>
+complex<_Tp>
+sqrt(const complex<_Tp>& __x)
+{
+    if (__libcpp_isinf_or_builtin(__x.imag()))
+        return complex<_Tp>(_Tp(INFINITY), __x.imag());
+    if (__libcpp_isinf_or_builtin(__x.real()))
+    {
+        if (__x.real() > _Tp(0))
+            return complex<_Tp>(__x.real(), __libcpp_isnan_or_builtin(__x.imag()) ? __x.imag() : copysign(_Tp(0), __x.imag()));
+        return complex<_Tp>(__libcpp_isnan_or_builtin(__x.imag()) ? __x.imag() : _Tp(0), copysign(__x.real(), __x.imag()));
+    }
+    return polar(sqrt(abs(__x)), arg(__x) / _Tp(2));
+}
+
+// exp
+
+template<class _Tp>
+complex<_Tp>
+exp(const complex<_Tp>& __x)
+{
+    _Tp __i = __x.imag();
+    if (__libcpp_isinf_or_builtin(__x.real()))
+    {
+        if (__x.real() < _Tp(0))
+        {
+            if (!__libcpp_isfinite_or_builtin(__i))
+                __i = _Tp(1);
+        }
+        else if (__i == 0 || !__libcpp_isfinite_or_builtin(__i))
+        {
+            if (__libcpp_isinf_or_builtin(__i))
+                __i = _Tp(NAN);
+            return complex<_Tp>(__x.real(), __i);
+        }
+    }
+    else if (__libcpp_isnan_or_builtin(__x.real()) && __x.imag() == 0)
+        return __x;
+    _Tp __e = exp(__x.real());
+    return complex<_Tp>(__e * cos(__i), __e * sin(__i));
+}
+
+// pow
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+pow(const complex<_Tp>& __x, const complex<_Tp>& __y)
+{
+    return exp(__y * log(__x));
+}
+
+template<class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<typename __promote<_Tp, _Up>::type>
+pow(const complex<_Tp>& __x, const complex<_Up>& __y)
+{
+    typedef complex<typename __promote<_Tp, _Up>::type> result_type;
+    return _VSTD::pow(result_type(__x), result_type(__y));
+}
+
+template<class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_arithmetic<_Up>::value,
+    complex<typename __promote<_Tp, _Up>::type>
+>::type
+pow(const complex<_Tp>& __x, const _Up& __y)
+{
+    typedef complex<typename __promote<_Tp, _Up>::type> result_type;
+    return _VSTD::pow(result_type(__x), result_type(__y));
+}
+
+template<class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_arithmetic<_Tp>::value,
+    complex<typename __promote<_Tp, _Up>::type>
+>::type
+pow(const _Tp& __x, const complex<_Up>& __y)
+{
+    typedef complex<typename __promote<_Tp, _Up>::type> result_type;
+    return _VSTD::pow(result_type(__x), result_type(__y));
+}
+
+// __sqr, computes pow(x, 2)
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+__sqr(const complex<_Tp>& __x)
+{
+    return complex<_Tp>((__x.real() - __x.imag()) * (__x.real() + __x.imag()),
+                        _Tp(2) * __x.real() * __x.imag());
+}
+
+// asinh
+
+template<class _Tp>
+complex<_Tp>
+asinh(const complex<_Tp>& __x)
+{
+    const _Tp __pi(atan2(+0., -0.));
+    if (__libcpp_isinf_or_builtin(__x.real()))
+    {
+        if (__libcpp_isnan_or_builtin(__x.imag()))
+            return __x;
+        if (__libcpp_isinf_or_builtin(__x.imag()))
+            return complex<_Tp>(__x.real(), copysign(__pi * _Tp(0.25), __x.imag()));
+        return complex<_Tp>(__x.real(), copysign(_Tp(0), __x.imag()));
+    }
+    if (__libcpp_isnan_or_builtin(__x.real()))
+    {
+        if (__libcpp_isinf_or_builtin(__x.imag()))
+            return complex<_Tp>(__x.imag(), __x.real());
+        if (__x.imag() == 0)
+            return __x;
+        return complex<_Tp>(__x.real(), __x.real());
+    }
+    if (__libcpp_isinf_or_builtin(__x.imag()))
+        return complex<_Tp>(copysign(__x.imag(), __x.real()), copysign(__pi/_Tp(2), __x.imag()));
+    complex<_Tp> __z = log(__x + sqrt(__sqr(__x) + _Tp(1)));
+    return complex<_Tp>(copysign(__z.real(), __x.real()), copysign(__z.imag(), __x.imag()));
+}
+
+// acosh
+
+template<class _Tp>
+complex<_Tp>
+acosh(const complex<_Tp>& __x)
+{
+    const _Tp __pi(atan2(+0., -0.));
+    if (__libcpp_isinf_or_builtin(__x.real()))
+    {
+        if (__libcpp_isnan_or_builtin(__x.imag()))
+            return complex<_Tp>(abs(__x.real()), __x.imag());
+        if (__libcpp_isinf_or_builtin(__x.imag()))
+        {
+            if (__x.real() > 0)
+                return complex<_Tp>(__x.real(), copysign(__pi * _Tp(0.25), __x.imag()));
+            else
+                return complex<_Tp>(-__x.real(), copysign(__pi * _Tp(0.75), __x.imag()));
+        }
+        if (__x.real() < 0)
+            return complex<_Tp>(-__x.real(), copysign(__pi, __x.imag()));
+        return complex<_Tp>(__x.real(), copysign(_Tp(0), __x.imag()));
+    }
+    if (__libcpp_isnan_or_builtin(__x.real()))
+    {
+        if (__libcpp_isinf_or_builtin(__x.imag()))
+            return complex<_Tp>(abs(__x.imag()), __x.real());
+        return complex<_Tp>(__x.real(), __x.real());
+    }
+    if (__libcpp_isinf_or_builtin(__x.imag()))
+        return complex<_Tp>(abs(__x.imag()), copysign(__pi/_Tp(2), __x.imag()));
+    complex<_Tp> __z = log(__x + sqrt(__sqr(__x) - _Tp(1)));
+    return complex<_Tp>(copysign(__z.real(), _Tp(0)), copysign(__z.imag(), __x.imag()));
+}
+
+// atanh
+
+template<class _Tp>
+complex<_Tp>
+atanh(const complex<_Tp>& __x)
+{
+    const _Tp __pi(atan2(+0., -0.));
+    if (__libcpp_isinf_or_builtin(__x.imag()))
+    {
+        return complex<_Tp>(copysign(_Tp(0), __x.real()), copysign(__pi/_Tp(2), __x.imag()));
+    }
+    if (__libcpp_isnan_or_builtin(__x.imag()))
+    {
+        if (__libcpp_isinf_or_builtin(__x.real()) || __x.real() == 0)
+            return complex<_Tp>(copysign(_Tp(0), __x.real()), __x.imag());
+        return complex<_Tp>(__x.imag(), __x.imag());
+    }
+    if (__libcpp_isnan_or_builtin(__x.real()))
+    {
+        return complex<_Tp>(__x.real(), __x.real());
+    }
+    if (__libcpp_isinf_or_builtin(__x.real()))
+    {
+        return complex<_Tp>(copysign(_Tp(0), __x.real()), copysign(__pi/_Tp(2), __x.imag()));
+    }
+    if (abs(__x.real()) == _Tp(1) && __x.imag() == _Tp(0))
+    {
+        return complex<_Tp>(copysign(_Tp(INFINITY), __x.real()), copysign(_Tp(0), __x.imag()));
+    }
+    complex<_Tp> __z = log((_Tp(1) + __x) / (_Tp(1) - __x)) / _Tp(2);
+    return complex<_Tp>(copysign(__z.real(), __x.real()), copysign(__z.imag(), __x.imag()));
+}
+
+// sinh
+
+template<class _Tp>
+complex<_Tp>
+sinh(const complex<_Tp>& __x)
+{
+    if (__libcpp_isinf_or_builtin(__x.real()) && !__libcpp_isfinite_or_builtin(__x.imag()))
+        return complex<_Tp>(__x.real(), _Tp(NAN));
+    if (__x.real() == 0 && !__libcpp_isfinite_or_builtin(__x.imag()))
+        return complex<_Tp>(__x.real(), _Tp(NAN));
+    if (__x.imag() == 0 && !__libcpp_isfinite_or_builtin(__x.real()))
+        return __x;
+    return complex<_Tp>(sinh(__x.real()) * cos(__x.imag()), cosh(__x.real()) * sin(__x.imag()));
+}
+
+// cosh
+
+template<class _Tp>
+complex<_Tp>
+cosh(const complex<_Tp>& __x)
+{
+    if (__libcpp_isinf_or_builtin(__x.real()) && !__libcpp_isfinite_or_builtin(__x.imag()))
+        return complex<_Tp>(abs(__x.real()), _Tp(NAN));
+    if (__x.real() == 0 && !__libcpp_isfinite_or_builtin(__x.imag()))
+        return complex<_Tp>(_Tp(NAN), __x.real());
+    if (__x.real() == 0 && __x.imag() == 0)
+        return complex<_Tp>(_Tp(1), __x.imag());
+    if (__x.imag() == 0 && !__libcpp_isfinite_or_builtin(__x.real()))
+        return complex<_Tp>(abs(__x.real()), __x.imag());
+    return complex<_Tp>(cosh(__x.real()) * cos(__x.imag()), sinh(__x.real()) * sin(__x.imag()));
+}
+
+// tanh
+
+template<class _Tp>
+complex<_Tp>
+tanh(const complex<_Tp>& __x)
+{
+    if (__libcpp_isinf_or_builtin(__x.real()))
+    {
+        if (!__libcpp_isfinite_or_builtin(__x.imag()))
+            return complex<_Tp>(_Tp(1), _Tp(0));
+        return complex<_Tp>(_Tp(1), copysign(_Tp(0), sin(_Tp(2) * __x.imag())));
+    }
+    if (__libcpp_isnan_or_builtin(__x.real()) && __x.imag() == 0)
+        return __x;
+    _Tp __2r(_Tp(2) * __x.real());
+    _Tp __2i(_Tp(2) * __x.imag());
+    _Tp __d(cosh(__2r) + cos(__2i));
+    _Tp __2rsh(sinh(__2r));
+    if (__libcpp_isinf_or_builtin(__2rsh) && __libcpp_isinf_or_builtin(__d))
+        return complex<_Tp>(__2rsh > _Tp(0) ? _Tp(1) : _Tp(-1),
+                            __2i > _Tp(0) ? _Tp(0) : _Tp(-0.));
+    return  complex<_Tp>(__2rsh/__d, sin(__2i)/__d);
+}
+
+// asin
+
+template<class _Tp>
+complex<_Tp>
+asin(const complex<_Tp>& __x)
+{
+    complex<_Tp> __z = asinh(complex<_Tp>(-__x.imag(), __x.real()));
+    return complex<_Tp>(__z.imag(), -__z.real());
+}
+
+// acos
+
+template<class _Tp>
+complex<_Tp>
+acos(const complex<_Tp>& __x)
+{
+    const _Tp __pi(atan2(+0., -0.));
+    if (__libcpp_isinf_or_builtin(__x.real()))
+    {
+        if (__libcpp_isnan_or_builtin(__x.imag()))
+            return complex<_Tp>(__x.imag(), __x.real());
+        if (__libcpp_isinf_or_builtin(__x.imag()))
+        {
+            if (__x.real() < _Tp(0))
+                return complex<_Tp>(_Tp(0.75) * __pi, -__x.imag());
+            return complex<_Tp>(_Tp(0.25) * __pi, -__x.imag());
+        }
+        if (__x.real() < _Tp(0))
+            return complex<_Tp>(__pi, signbit(__x.imag()) ? -__x.real() : __x.real());
+        return complex<_Tp>(_Tp(0), signbit(__x.imag()) ? __x.real() : -__x.real());
+    }
+    if (__libcpp_isnan_or_builtin(__x.real()))
+    {
+        if (__libcpp_isinf_or_builtin(__x.imag()))
+            return complex<_Tp>(__x.real(), -__x.imag());
+        return complex<_Tp>(__x.real(), __x.real());
+    }
+    if (__libcpp_isinf_or_builtin(__x.imag()))
+        return complex<_Tp>(__pi/_Tp(2), -__x.imag());
+    if (__x.real() == 0 && (__x.imag() == 0 || isnan(__x.imag())))
+        return complex<_Tp>(__pi/_Tp(2), -__x.imag());
+    complex<_Tp> __z = log(__x + sqrt(__sqr(__x) - _Tp(1)));
+    if (signbit(__x.imag()))
+        return complex<_Tp>(abs(__z.imag()), abs(__z.real()));
+    return complex<_Tp>(abs(__z.imag()), -abs(__z.real()));
+}
+
+// atan
+
+template<class _Tp>
+complex<_Tp>
+atan(const complex<_Tp>& __x)
+{
+    complex<_Tp> __z = atanh(complex<_Tp>(-__x.imag(), __x.real()));
+    return complex<_Tp>(__z.imag(), -__z.real());
+}
+
+// sin
+
+template<class _Tp>
+complex<_Tp>
+sin(const complex<_Tp>& __x)
+{
+    complex<_Tp> __z = sinh(complex<_Tp>(-__x.imag(), __x.real()));
+    return complex<_Tp>(__z.imag(), -__z.real());
+}
+
+// cos
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+complex<_Tp>
+cos(const complex<_Tp>& __x)
+{
+    return cosh(complex<_Tp>(-__x.imag(), __x.real()));
+}
+
+// tan
+
+template<class _Tp>
+complex<_Tp>
+tan(const complex<_Tp>& __x)
+{
+    complex<_Tp> __z = tanh(complex<_Tp>(-__x.imag(), __x.real()));
+    return complex<_Tp>(__z.imag(), -__z.real());
+}
+
+template<class _Tp, class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, complex<_Tp>& __x)
+{
+    if (__is.good())
+    {
+        ws(__is);
+        if (__is.peek() == _CharT('('))
+        {
+            __is.get();
+            _Tp __r;
+            __is >> __r;
+            if (!__is.fail())
+            {
+                ws(__is);
+                _CharT __c = __is.peek();
+                if (__c == _CharT(','))
+                {
+                    __is.get();
+                    _Tp __i;
+                    __is >> __i;
+                    if (!__is.fail())
+                    {
+                        ws(__is);
+                        __c = __is.peek();
+                        if (__c == _CharT(')'))
+                        {
+                            __is.get();
+                            __x = complex<_Tp>(__r, __i);
+                        }
+                        else
+                            __is.setstate(__is.failbit);
+                    }
+                    else
+                        __is.setstate(__is.failbit);
+                }
+                else if (__c == _CharT(')'))
+                {
+                    __is.get();
+                    __x = complex<_Tp>(__r, _Tp(0));
+                }
+                else
+                    __is.setstate(__is.failbit);
+            }
+            else
+                __is.setstate(__is.failbit);
+        }
+        else
+        {
+            _Tp __r;
+            __is >> __r;
+            if (!__is.fail())
+                __x = complex<_Tp>(__r, _Tp(0));
+            else
+                __is.setstate(__is.failbit);
+        }
+    }
+    else
+        __is.setstate(__is.failbit);
+    return __is;
+}
+
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+template<class _Tp, class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const complex<_Tp>& __x)
+{
+    basic_ostringstream<_CharT, _Traits> __s;
+    __s.flags(__os.flags());
+    __s.imbue(__os.getloc());
+    __s.precision(__os.precision());
+    __s << '(' << __x.real() << ',' << __x.imag() << ')';
+    return __os << __s.str();
+}
+#endif // !_LIBCPP_HAS_NO_LOCALIZATION
+
+#if _LIBCPP_STD_VER > 11
+// Literal suffix for complex number literals [complex.literals]
+inline namespace literals
+{
+  inline namespace complex_literals
+  {
+    constexpr complex<long double> operator""il(long double __im)
+    {
+        return { 0.0l, __im };
+    }
+
+    constexpr complex<long double> operator""il(unsigned long long __im)
+    {
+        return { 0.0l, static_cast<long double>(__im) };
+    }
+
+
+    constexpr complex<double> operator""i(long double __im)
+    {
+        return { 0.0, static_cast<double>(__im) };
+    }
+
+    constexpr complex<double> operator""i(unsigned long long __im)
+    {
+        return { 0.0, static_cast<double>(__im) };
+    }
+
+
+#if !defined(__CUDACC__)
+    constexpr complex<float> operator""if(long double __im)
+    {
+        return { 0.0f, static_cast<float>(__im) };
+    }
+
+    constexpr complex<float> operator""if(unsigned long long __im)
+    {
+        return { 0.0f, static_cast<float>(__im) };
+    }
+#endif
+  }
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_COMPLEX
diff --git a/contrib/libs/cxxsupp/libcxx/include/complex.h b/contrib/libs/cxxsupp/libcxx/include/complex.h
new file mode 100644
index 00000000000..b614759adac
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/complex.h
@@ -0,0 +1,40 @@
+// -*- C++ -*-
+//===--------------------------- complex.h --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_COMPLEX_H
+#define _LIBCPP_COMPLEX_H
+
+/*
+    complex.h synopsis
+
+#include <ccomplex>
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef __cplusplus
+
+#include <ccomplex>
+
+#else  // __cplusplus
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(complex.h)
+#else
+#include_next <complex.h>
+#endif
+
+#endif // __cplusplus
+
+#endif // _LIBCPP_COMPLEX_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/concepts b/contrib/libs/cxxsupp/libcxx/include/concepts
new file mode 100644
index 00000000000..bfa27ddca0d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/concepts
@@ -0,0 +1,161 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CONCEPTS
+#define _LIBCPP_CONCEPTS
+
+/*
+    concepts synopsis
+namespace std {
+  // [concepts.lang], language-related concepts
+  // [concept.same], concept same_as
+  template<class T, class U>
+    concept same_as = see below;
+
+  // [concept.derived], concept derived_from
+  template<class Derived, class Base>
+    concept derived_from = see below;
+
+  // [concept.convertible], concept convertible_to
+  template<class From, class To>
+    concept convertible_to = see below;
+
+  // [concept.commonref], concept common_reference_with
+  template<class T, class U>
+    concept common_reference_with = see below;
+
+  // [concept.common], concept common_with
+  template<class T, class U>
+    concept common_with = see below;
+
+  // [concepts.arithmetic], arithmetic concepts
+  template<class T>
+    concept integral = see below;
+  template<class T>
+    concept signed_integral = see below;
+  template<class T>
+    concept unsigned_integral = see below;
+  template<class T>
+    concept floating_point = see below;
+
+  // [concept.assignable], concept assignable_from
+  template<class LHS, class RHS>
+    concept assignable_from = see below;
+
+  // [concept.swappable], concept swappable
+  namespace ranges {
+    inline namespace unspecified {
+      inline constexpr unspecified swap = unspecified;
+    }
+  }
+  template<class T>
+    concept swappable = see below;
+  template<class T, class U>
+    concept swappable_with = see below;
+
+  // [concept.destructible], concept destructible
+  template<class T>
+    concept destructible = see below;
+
+  // [concept.constructible], concept constructible_from
+  template<class T, class... Args>
+    concept constructible_from = see below;
+
+  // [concept.default.init], concept default_initializable
+  template<class T>
+    concept default_initializable = see below;
+
+  // [concept.moveconstructible], concept move_constructible
+  template<class T>
+    concept move_constructible = see below;
+
+  // [concept.copyconstructible], concept copy_constructible
+  template<class T>
+    concept copy_constructible = see below;
+
+  // [concept.equalitycomparable], concept equality_comparable
+  template<class T>
+    concept equality_comparable = see below;
+  template<class T, class U>
+    concept equality_comparable_with = see below;
+
+  // [concept.totallyordered], concept totally_ordered
+  template<class T>
+    concept totally_ordered = see below;
+  template<class T, class U>
+    concept totally_ordered_with = see below;
+
+  // [concepts.object], object concepts
+  template<class T>
+    concept movable = see below;
+  template<class T>
+    concept copyable = see below;
+  template<class T>
+    concept semiregular = see below;
+  template<class T>
+    concept regular = see below;
+
+  // [concepts.callable], callable concepts
+  // [concept.invocable], concept invocable
+  template<class F, class... Args>
+    concept invocable = see below;
+
+  // [concept.regularinvocable], concept regular_invocable
+  template<class F, class... Args>
+    concept regular_invocable = see below;
+
+  // [concept.predicate], concept predicate
+  template<class F, class... Args>
+    concept predicate = see below;
+
+  // [concept.relation], concept relation
+  template<class R, class T, class U>
+    concept relation = see below;
+
+  // [concept.equiv], concept equivalence_relation
+  template<class R, class T, class U>
+    concept equivalence_relation = see below;
+
+  // [concept.strictweakorder], concept strict_weak_order
+  template<class R, class T, class U>
+    concept strict_weak_order = see below;
+}
+
+*/
+
+#include <__concepts/arithmetic.h>
+#include <__concepts/assignable.h>
+#include <__concepts/boolean_testable.h>
+#include <__concepts/class_or_enum.h>
+#include <__concepts/common_reference_with.h>
+#include <__concepts/common_with.h>
+#include <__concepts/constructible.h>
+#include <__concepts/convertible_to.h>
+#include <__concepts/copyable.h>
+#include <__concepts/derived_from.h>
+#include <__concepts/destructible.h>
+#include <__concepts/different_from.h>
+#include <__concepts/equality_comparable.h>
+#include <__concepts/invocable.h>
+#include <__concepts/movable.h>
+#include <__concepts/predicate.h>
+#include <__concepts/regular.h>
+#include <__concepts/relation.h>
+#include <__concepts/same_as.h>
+#include <__concepts/semiregular.h>
+#include <__concepts/swappable.h>
+#include <__concepts/totally_ordered.h>
+#include <__config>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#endif // _LIBCPP_CONCEPTS
diff --git a/contrib/libs/cxxsupp/libcxx/include/condition_variable b/contrib/libs/cxxsupp/libcxx/include/condition_variable
new file mode 100644
index 00000000000..a33250c6779
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/condition_variable
@@ -0,0 +1,268 @@
+// -*- C++ -*-
+//===---------------------- condition_variable ----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CONDITION_VARIABLE
+#define _LIBCPP_CONDITION_VARIABLE
+
+/*
+    condition_variable synopsis
+
+namespace std
+{
+
+enum class cv_status { no_timeout, timeout };
+
+class condition_variable
+{
+public:
+    condition_variable();
+    ~condition_variable();
+
+    condition_variable(const condition_variable&) = delete;
+    condition_variable& operator=(const condition_variable&) = delete;
+
+    void notify_one() noexcept;
+    void notify_all() noexcept;
+
+    void wait(unique_lock<mutex>& lock);
+    template <class Predicate>
+        void wait(unique_lock<mutex>& lock, Predicate pred);
+
+    template <class Clock, class Duration>
+        cv_status
+        wait_until(unique_lock<mutex>& lock,
+                   const chrono::time_point<Clock, Duration>& abs_time);
+
+    template <class Clock, class Duration, class Predicate>
+        bool
+        wait_until(unique_lock<mutex>& lock,
+                   const chrono::time_point<Clock, Duration>& abs_time,
+                   Predicate pred);
+
+    template <class Rep, class Period>
+        cv_status
+        wait_for(unique_lock<mutex>& lock,
+                 const chrono::duration<Rep, Period>& rel_time);
+
+    template <class Rep, class Period, class Predicate>
+        bool
+        wait_for(unique_lock<mutex>& lock,
+                 const chrono::duration<Rep, Period>& rel_time,
+                 Predicate pred);
+
+    typedef pthread_cond_t* native_handle_type;
+    native_handle_type native_handle();
+};
+
+void notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk);
+
+class condition_variable_any
+{
+public:
+    condition_variable_any();
+    ~condition_variable_any();
+
+    condition_variable_any(const condition_variable_any&) = delete;
+    condition_variable_any& operator=(const condition_variable_any&) = delete;
+
+    void notify_one() noexcept;
+    void notify_all() noexcept;
+
+    template <class Lock>
+        void wait(Lock& lock);
+    template <class Lock, class Predicate>
+        void wait(Lock& lock, Predicate pred);
+
+    template <class Lock, class Clock, class Duration>
+        cv_status
+        wait_until(Lock& lock,
+                   const chrono::time_point<Clock, Duration>& abs_time);
+
+    template <class Lock, class Clock, class Duration, class Predicate>
+        bool
+        wait_until(Lock& lock,
+                   const chrono::time_point<Clock, Duration>& abs_time,
+                   Predicate pred);
+
+    template <class Lock, class Rep, class Period>
+        cv_status
+        wait_for(Lock& lock,
+                 const chrono::duration<Rep, Period>& rel_time);
+
+    template <class Lock, class Rep, class Period, class Predicate>
+        bool
+        wait_for(Lock& lock,
+                 const chrono::duration<Rep, Period>& rel_time,
+                 Predicate pred);
+};
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__mutex_base>
+#include <memory>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+class _LIBCPP_TYPE_VIS condition_variable_any
+{
+    condition_variable __cv_;
+    shared_ptr<mutex>  __mut_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    condition_variable_any();
+
+    _LIBCPP_INLINE_VISIBILITY
+    void notify_one() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    void notify_all() _NOEXCEPT;
+
+    template <class _Lock>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        void wait(_Lock& __lock);
+    template <class _Lock, class _Predicate>
+        _LIBCPP_INLINE_VISIBILITY
+        void wait(_Lock& __lock, _Predicate __pred);
+
+    template <class _Lock, class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        cv_status
+        wait_until(_Lock& __lock,
+                   const chrono::time_point<_Clock, _Duration>& __t);
+
+    template <class _Lock, class _Clock, class _Duration, class _Predicate>
+        bool
+        _LIBCPP_INLINE_VISIBILITY
+        wait_until(_Lock& __lock,
+                   const chrono::time_point<_Clock, _Duration>& __t,
+                   _Predicate __pred);
+
+    template <class _Lock, class _Rep, class _Period>
+        cv_status
+        _LIBCPP_INLINE_VISIBILITY
+        wait_for(_Lock& __lock,
+                 const chrono::duration<_Rep, _Period>& __d);
+
+    template <class _Lock, class _Rep, class _Period, class _Predicate>
+        bool
+        _LIBCPP_INLINE_VISIBILITY
+        wait_for(_Lock& __lock,
+                 const chrono::duration<_Rep, _Period>& __d,
+                 _Predicate __pred);
+};
+
+inline
+condition_variable_any::condition_variable_any()
+    : __mut_(make_shared<mutex>()) {}
+
+inline
+void
+condition_variable_any::notify_one() _NOEXCEPT
+{
+    {lock_guard<mutex> __lx(*__mut_);}
+    __cv_.notify_one();
+}
+
+inline
+void
+condition_variable_any::notify_all() _NOEXCEPT
+{
+    {lock_guard<mutex> __lx(*__mut_);}
+    __cv_.notify_all();
+}
+
+struct __lock_external
+{
+    template <class _Lock>
+    void operator()(_Lock* __m) {__m->lock();}
+};
+
+template <class _Lock>
+void
+condition_variable_any::wait(_Lock& __lock)
+{
+    shared_ptr<mutex> __mut = __mut_;
+    unique_lock<mutex> __lk(*__mut);
+    __lock.unlock();
+    unique_ptr<_Lock, __lock_external> __lxx(&__lock);
+    lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock);
+    __cv_.wait(__lk);
+}  // __mut_.unlock(), __lock.lock()
+
+template <class _Lock, class _Predicate>
+inline
+void
+condition_variable_any::wait(_Lock& __lock, _Predicate __pred)
+{
+    while (!__pred())
+        wait(__lock);
+}
+
+template <class _Lock, class _Clock, class _Duration>
+cv_status
+condition_variable_any::wait_until(_Lock& __lock,
+                                   const chrono::time_point<_Clock, _Duration>& __t)
+{
+    shared_ptr<mutex> __mut = __mut_;
+    unique_lock<mutex> __lk(*__mut);
+    __lock.unlock();
+    unique_ptr<_Lock, __lock_external> __lxx(&__lock);
+    lock_guard<unique_lock<mutex> > __lx(__lk, adopt_lock);
+    return __cv_.wait_until(__lk, __t);
+}  // __mut_.unlock(), __lock.lock()
+
+template <class _Lock, class _Clock, class _Duration, class _Predicate>
+inline
+bool
+condition_variable_any::wait_until(_Lock& __lock,
+                                   const chrono::time_point<_Clock, _Duration>& __t,
+                                   _Predicate __pred)
+{
+    while (!__pred())
+        if (wait_until(__lock, __t) == cv_status::timeout)
+            return __pred();
+    return true;
+}
+
+template <class _Lock, class _Rep, class _Period>
+inline
+cv_status
+condition_variable_any::wait_for(_Lock& __lock,
+                                 const chrono::duration<_Rep, _Period>& __d)
+{
+    return wait_until(__lock, chrono::steady_clock::now() + __d);
+}
+
+template <class _Lock, class _Rep, class _Period, class _Predicate>
+inline
+bool
+condition_variable_any::wait_for(_Lock& __lock,
+                                 const chrono::duration<_Rep, _Period>& __d,
+                                 _Predicate __pred)
+{
+    return wait_until(__lock, chrono::steady_clock::now() + __d,
+                      _VSTD::move(__pred));
+}
+
+_LIBCPP_FUNC_VIS
+void notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk);
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !_LIBCPP_HAS_NO_THREADS
+
+#endif // _LIBCPP_CONDITION_VARIABLE
diff --git a/contrib/libs/cxxsupp/libcxx/include/csetjmp b/contrib/libs/cxxsupp/libcxx/include/csetjmp
new file mode 100644
index 00000000000..41902f0e471
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/csetjmp
@@ -0,0 +1,47 @@
+// -*- C++ -*-
+//===--------------------------- csetjmp ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CSETJMP
+#define _LIBCPP_CSETJMP
+
+/*
+    csetjmp synopsis
+
+Macros:
+
+    setjmp
+
+namespace std
+{
+
+Types:
+
+    jmp_buf
+
+void longjmp(jmp_buf env, int val);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <setjmp.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::jmp_buf _LIBCPP_USING_IF_EXISTS;
+using ::longjmp _LIBCPP_USING_IF_EXISTS;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CSETJMP
diff --git a/contrib/libs/cxxsupp/libcxx/include/csignal b/contrib/libs/cxxsupp/libcxx/include/csignal
new file mode 100644
index 00000000000..3b262b561a4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/csignal
@@ -0,0 +1,57 @@
+// -*- C++ -*-
+//===--------------------------- csignal ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CSIGNAL
+#define _LIBCPP_CSIGNAL
+
+/*
+    csignal synopsis
+
+Macros:
+
+    SIG_DFL
+    SIG_ERR
+    SIG_IGN
+    SIGABRT
+    SIGFPE
+    SIGILL
+    SIGINT
+    SIGSEGV
+    SIGTERM
+
+namespace std
+{
+
+Types:
+
+    sig_atomic_t
+
+void (*signal(int sig, void (*func)(int)))(int);
+int raise(int sig);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <signal.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::sig_atomic_t _LIBCPP_USING_IF_EXISTS;
+using ::signal _LIBCPP_USING_IF_EXISTS;
+using ::raise _LIBCPP_USING_IF_EXISTS;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CSIGNAL
diff --git a/contrib/libs/cxxsupp/libcxx/include/cstdarg b/contrib/libs/cxxsupp/libcxx/include/cstdarg
new file mode 100644
index 00000000000..352db8b8c1d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cstdarg
@@ -0,0 +1,47 @@
+// -*- C++ -*-
+//===--------------------------- cstdarg ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CSTDARG
+#define _LIBCPP_CSTDARG
+
+/*
+    cstdarg synopsis
+
+Macros:
+
+    type va_arg(va_list ap, type);
+    void va_copy(va_list dest, va_list src);  // C99
+    void va_end(va_list ap);
+    void va_start(va_list ap, parmN);
+
+namespace std
+{
+
+Types:
+
+    va_list
+
+}  // std
+
+*/
+
+#include <__config>
+#include <stdarg.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::va_list _LIBCPP_USING_IF_EXISTS;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CSTDARG
diff --git a/contrib/libs/cxxsupp/libcxx/include/cstdbool b/contrib/libs/cxxsupp/libcxx/include/cstdbool
new file mode 100644
index 00000000000..7708537ca8e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cstdbool
@@ -0,0 +1,31 @@
+// -*- C++ -*-
+//===--------------------------- cstdbool ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CSTDBOOL
+#define _LIBCPP_CSTDBOOL
+
+/*
+    cstdbool synopsis
+
+Macros:
+
+    __bool_true_false_are_defined
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#undef __bool_true_false_are_defined
+#define __bool_true_false_are_defined 1
+
+#endif // _LIBCPP_CSTDBOOL
diff --git a/contrib/libs/cxxsupp/libcxx/include/cstddef b/contrib/libs/cxxsupp/libcxx/include/cstddef
new file mode 100644
index 00000000000..e7673037d39
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cstddef
@@ -0,0 +1,170 @@
+// -*- C++ -*-
+//===--------------------------- cstddef ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CSTDDEF
+#define _LIBCPP_CSTDDEF
+
+/*
+    cstddef synopsis
+
+Macros:
+
+    offsetof(type,member-designator)
+    NULL
+
+namespace std
+{
+
+Types:
+
+    ptrdiff_t
+    size_t
+    max_align_t // C++11
+    nullptr_t
+    byte // C++17
+
+}  // std
+
+*/
+
+#include <__config>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+// Don't include our own <stddef.h>; we don't want to declare ::nullptr_t.
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(stddef.h)
+#else
+#include_next <stddef.h>
+#endif
+#ifdef _LIBCPP_ABI_VCRUNTIME
+typedef double max_align_t;
+#endif
+#include <__nullptr>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::ptrdiff_t _LIBCPP_USING_IF_EXISTS;
+using ::size_t _LIBCPP_USING_IF_EXISTS;
+
+#if !defined(_LIBCPP_CXX03_LANG)
+using ::max_align_t _LIBCPP_USING_IF_EXISTS;
+#endif
+
+template <class _Tp> struct __libcpp_is_integral                     { enum { value = 0 }; };
+template <>          struct __libcpp_is_integral<bool>               { enum { value = 1 }; };
+template <>          struct __libcpp_is_integral<char>               { enum { value = 1 }; };
+template <>          struct __libcpp_is_integral<signed char>        { enum { value = 1 }; };
+template <>          struct __libcpp_is_integral<unsigned char>      { enum { value = 1 }; };
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>          struct __libcpp_is_integral<wchar_t>            { enum { value = 1 }; };
+#endif
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+template <>          struct __libcpp_is_integral<char8_t>            { enum { value = 1 }; };
+#endif
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+template <>          struct __libcpp_is_integral<char16_t>           { enum { value = 1 }; };
+template <>          struct __libcpp_is_integral<char32_t>           { enum { value = 1 }; };
+#endif
+template <>          struct __libcpp_is_integral<short>              { enum { value = 1 }; };
+template <>          struct __libcpp_is_integral<unsigned short>     { enum { value = 1 }; };
+template <>          struct __libcpp_is_integral<int>                { enum { value = 1 }; };
+template <>          struct __libcpp_is_integral<unsigned int>       { enum { value = 1 }; };
+template <>          struct __libcpp_is_integral<long>               { enum { value = 1 }; };
+template <>          struct __libcpp_is_integral<unsigned long>      { enum { value = 1 }; };
+template <>          struct __libcpp_is_integral<long long>          { enum { value = 1 }; };
+template <>          struct __libcpp_is_integral<unsigned long long> { enum { value = 1 }; };
+#ifndef _LIBCPP_HAS_NO_INT128
+template <>          struct __libcpp_is_integral<__int128_t>         { enum { value = 1 }; };
+template <>          struct __libcpp_is_integral<__uint128_t>        { enum { value = 1 }; };
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+namespace std  // purposefully not versioned
+{
+enum class byte : unsigned char {};
+
+
+template <bool> struct __enable_if_integral_imp {};
+template <> struct __enable_if_integral_imp<true> { using type = byte; };
+template <class _Tp> using _EnableByteOverload = typename __enable_if_integral_imp<__libcpp_is_integral<_Tp>::value>::type;
+
+constexpr byte  operator| (byte  __lhs, byte __rhs) noexcept
+{
+    return static_cast<byte>(
+      static_cast<unsigned char>(
+         static_cast<unsigned int>(__lhs) | static_cast<unsigned int>(__rhs)
+    ));
+}
+
+constexpr byte& operator|=(byte& __lhs, byte __rhs) noexcept
+{ return __lhs = __lhs | __rhs; }
+
+constexpr byte  operator& (byte  __lhs, byte __rhs) noexcept
+{
+    return static_cast<byte>(
+      static_cast<unsigned char>(
+         static_cast<unsigned int>(__lhs) & static_cast<unsigned int>(__rhs)
+    ));
+}
+
+constexpr byte& operator&=(byte& __lhs, byte __rhs) noexcept
+{ return __lhs = __lhs & __rhs; }
+
+constexpr byte  operator^ (byte  __lhs, byte __rhs) noexcept
+{
+    return static_cast<byte>(
+      static_cast<unsigned char>(
+         static_cast<unsigned int>(__lhs) ^ static_cast<unsigned int>(__rhs)
+    ));
+}
+
+constexpr byte& operator^=(byte& __lhs, byte __rhs) noexcept
+{ return __lhs = __lhs ^ __rhs; }
+
+constexpr byte  operator~ (byte __b) noexcept
+{
+    return static_cast<byte>(
+      static_cast<unsigned char>(
+        ~static_cast<unsigned int>(__b)
+    ));
+}
+template <class _Integer>
+  constexpr _EnableByteOverload<_Integer> &
+  operator<<=(byte& __lhs, _Integer __shift) noexcept
+  { return __lhs = __lhs << __shift; }
+
+template <class _Integer>
+  constexpr _EnableByteOverload<_Integer>
+  operator<< (byte  __lhs, _Integer __shift) noexcept
+  { return static_cast<byte>(static_cast<unsigned char>(static_cast<unsigned int>(__lhs) << __shift)); }
+
+template <class _Integer>
+  constexpr _EnableByteOverload<_Integer> &
+  operator>>=(byte& __lhs, _Integer __shift) noexcept
+  { return __lhs = __lhs >> __shift; }
+
+template <class _Integer>
+  constexpr _EnableByteOverload<_Integer>
+  operator>> (byte  __lhs, _Integer __shift) noexcept
+  { return static_cast<byte>(static_cast<unsigned char>(static_cast<unsigned int>(__lhs) >> __shift)); }
+
+template <class _Integer, class = _EnableByteOverload<_Integer> >
+  _LIBCPP_NODISCARD_EXT constexpr _Integer
+  to_integer(byte __b) noexcept { return static_cast<_Integer>(__b); }
+}
+
+#endif
+
+#endif // _LIBCPP_CSTDDEF
diff --git a/contrib/libs/cxxsupp/libcxx/include/cstdint b/contrib/libs/cxxsupp/libcxx/include/cstdint
new file mode 100644
index 00000000000..aa7c8b5cbf5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cstdint
@@ -0,0 +1,190 @@
+// -*- C++ -*-
+//===--------------------------- cstdint ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CSTDINT
+#define _LIBCPP_CSTDINT
+
+/*
+    cstdint synopsis
+
+Macros:
+
+    INT8_MIN
+    INT16_MIN
+    INT32_MIN
+    INT64_MIN
+
+    INT8_MAX
+    INT16_MAX
+    INT32_MAX
+    INT64_MAX
+
+    UINT8_MAX
+    UINT16_MAX
+    UINT32_MAX
+    UINT64_MAX
+
+    INT_LEAST8_MIN
+    INT_LEAST16_MIN
+    INT_LEAST32_MIN
+    INT_LEAST64_MIN
+
+    INT_LEAST8_MAX
+    INT_LEAST16_MAX
+    INT_LEAST32_MAX
+    INT_LEAST64_MAX
+
+    UINT_LEAST8_MAX
+    UINT_LEAST16_MAX
+    UINT_LEAST32_MAX
+    UINT_LEAST64_MAX
+
+    INT_FAST8_MIN
+    INT_FAST16_MIN
+    INT_FAST32_MIN
+    INT_FAST64_MIN
+
+    INT_FAST8_MAX
+    INT_FAST16_MAX
+    INT_FAST32_MAX
+    INT_FAST64_MAX
+
+    UINT_FAST8_MAX
+    UINT_FAST16_MAX
+    UINT_FAST32_MAX
+    UINT_FAST64_MAX
+
+    INTPTR_MIN
+    INTPTR_MAX
+    UINTPTR_MAX
+
+    INTMAX_MIN
+    INTMAX_MAX
+
+    UINTMAX_MAX
+
+    PTRDIFF_MIN
+    PTRDIFF_MAX
+
+    SIG_ATOMIC_MIN
+    SIG_ATOMIC_MAX
+
+    SIZE_MAX
+
+    WCHAR_MIN
+    WCHAR_MAX
+
+    WINT_MIN
+    WINT_MAX
+
+    INT8_C(value)
+    INT16_C(value)
+    INT32_C(value)
+    INT64_C(value)
+
+    UINT8_C(value)
+    UINT16_C(value)
+    UINT32_C(value)
+    UINT64_C(value)
+
+    INTMAX_C(value)
+    UINTMAX_C(value)
+
+namespace std
+{
+
+Types:
+
+    int8_t
+    int16_t
+    int32_t
+    int64_t
+
+    uint8_t
+    uint16_t
+    uint32_t
+    uint64_t
+
+    int_least8_t
+    int_least16_t
+    int_least32_t
+    int_least64_t
+
+    uint_least8_t
+    uint_least16_t
+    uint_least32_t
+    uint_least64_t
+
+    int_fast8_t
+    int_fast16_t
+    int_fast32_t
+    int_fast64_t
+
+    uint_fast8_t
+    uint_fast16_t
+    uint_fast32_t
+    uint_fast64_t
+
+    intptr_t
+    uintptr_t
+
+    intmax_t
+    uintmax_t
+
+}  // std
+*/
+
+#include <__config>
+#include <stdint.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::int8_t _LIBCPP_USING_IF_EXISTS;
+using ::int16_t _LIBCPP_USING_IF_EXISTS;
+using ::int32_t _LIBCPP_USING_IF_EXISTS;
+using ::int64_t _LIBCPP_USING_IF_EXISTS;
+
+using ::uint8_t _LIBCPP_USING_IF_EXISTS;
+using ::uint16_t _LIBCPP_USING_IF_EXISTS;
+using ::uint32_t _LIBCPP_USING_IF_EXISTS;
+using ::uint64_t _LIBCPP_USING_IF_EXISTS;
+
+using ::int_least8_t _LIBCPP_USING_IF_EXISTS;
+using ::int_least16_t _LIBCPP_USING_IF_EXISTS;
+using ::int_least32_t _LIBCPP_USING_IF_EXISTS;
+using ::int_least64_t _LIBCPP_USING_IF_EXISTS;
+
+using ::uint_least8_t _LIBCPP_USING_IF_EXISTS;
+using ::uint_least16_t _LIBCPP_USING_IF_EXISTS;
+using ::uint_least32_t _LIBCPP_USING_IF_EXISTS;
+using ::uint_least64_t _LIBCPP_USING_IF_EXISTS;
+
+using ::int_fast8_t _LIBCPP_USING_IF_EXISTS;
+using ::int_fast16_t _LIBCPP_USING_IF_EXISTS;
+using ::int_fast32_t _LIBCPP_USING_IF_EXISTS;
+using ::int_fast64_t _LIBCPP_USING_IF_EXISTS;
+
+using ::uint_fast8_t _LIBCPP_USING_IF_EXISTS;
+using ::uint_fast16_t _LIBCPP_USING_IF_EXISTS;
+using ::uint_fast32_t _LIBCPP_USING_IF_EXISTS;
+using ::uint_fast64_t _LIBCPP_USING_IF_EXISTS;
+
+using ::intptr_t _LIBCPP_USING_IF_EXISTS;
+using ::uintptr_t _LIBCPP_USING_IF_EXISTS;
+
+using ::intmax_t _LIBCPP_USING_IF_EXISTS;
+using ::uintmax_t _LIBCPP_USING_IF_EXISTS;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CSTDINT
diff --git a/contrib/libs/cxxsupp/libcxx/include/cstdio b/contrib/libs/cxxsupp/libcxx/include/cstdio
new file mode 100644
index 00000000000..6a88bee6e81
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cstdio
@@ -0,0 +1,169 @@
+// -*- C++ -*-
+//===---------------------------- cstdio ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CSTDIO
+#define _LIBCPP_CSTDIO
+
+/*
+    cstdio synopsis
+
+Macros:
+
+    BUFSIZ
+    EOF
+    FILENAME_MAX
+    FOPEN_MAX
+    L_tmpnam
+    NULL
+    SEEK_CUR
+    SEEK_END
+    SEEK_SET
+    TMP_MAX
+    _IOFBF
+    _IOLBF
+    _IONBF
+    stderr
+    stdin
+    stdout
+
+namespace std
+{
+
+Types:
+
+FILE
+fpos_t
+size_t
+
+int remove(const char* filename);
+int rename(const char* old, const char* new);
+FILE* tmpfile(void);
+char* tmpnam(char* s);
+int fclose(FILE* stream);
+int fflush(FILE* stream);
+FILE* fopen(const char* restrict filename, const char* restrict mode);
+FILE* freopen(const char* restrict filename, const char * restrict mode,
+              FILE * restrict stream);
+void setbuf(FILE* restrict stream, char* restrict buf);
+int setvbuf(FILE* restrict stream, char* restrict buf, int mode, size_t size);
+int fprintf(FILE* restrict stream, const char* restrict format, ...);
+int fscanf(FILE* restrict stream, const char * restrict format, ...);
+int printf(const char* restrict format, ...);
+int scanf(const char* restrict format, ...);
+int snprintf(char* restrict s, size_t n, const char* restrict format, ...);    // C99
+int sprintf(char* restrict s, const char* restrict format, ...);
+int sscanf(const char* restrict s, const char* restrict format, ...);
+int vfprintf(FILE* restrict stream, const char* restrict format, va_list arg);
+int vfscanf(FILE* restrict stream, const char* restrict format, va_list arg);  // C99
+int vprintf(const char* restrict format, va_list arg);
+int vscanf(const char* restrict format, va_list arg);                          // C99
+int vsnprintf(char* restrict s, size_t n, const char* restrict format,         // C99
+              va_list arg);
+int vsprintf(char* restrict s, const char* restrict format, va_list arg);
+int vsscanf(const char* restrict s, const char* restrict format, va_list arg); // C99
+int fgetc(FILE* stream);
+char* fgets(char* restrict s, int n, FILE* restrict stream);
+int fputc(int c, FILE* stream);
+int fputs(const char* restrict s, FILE* restrict stream);
+int getc(FILE* stream);
+int getchar(void);
+char* gets(char* s);  // removed in C++14
+int putc(int c, FILE* stream);
+int putchar(int c);
+int puts(const char* s);
+int ungetc(int c, FILE* stream);
+size_t fread(void* restrict ptr, size_t size, size_t nmemb,
+             FILE* restrict stream);
+size_t fwrite(const void* restrict ptr, size_t size, size_t nmemb,
+              FILE* restrict stream);
+int fgetpos(FILE* restrict stream, fpos_t* restrict pos);
+int fseek(FILE* stream, long offset, int whence);
+int fsetpos(FILE*stream, const fpos_t* pos);
+long ftell(FILE* stream);
+void rewind(FILE* stream);
+void clearerr(FILE* stream);
+int feof(FILE* stream);
+int ferror(FILE* stream);
+void perror(const char* s);
+
+}  // std
+*/
+
+#include <__config>
+#include <stdio.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::FILE _LIBCPP_USING_IF_EXISTS;
+using ::fpos_t _LIBCPP_USING_IF_EXISTS;
+using ::size_t _LIBCPP_USING_IF_EXISTS;
+
+using ::fclose _LIBCPP_USING_IF_EXISTS;
+using ::fflush _LIBCPP_USING_IF_EXISTS;
+using ::setbuf _LIBCPP_USING_IF_EXISTS;
+using ::setvbuf _LIBCPP_USING_IF_EXISTS;
+using ::fprintf _LIBCPP_USING_IF_EXISTS;
+using ::fscanf _LIBCPP_USING_IF_EXISTS;
+using ::snprintf _LIBCPP_USING_IF_EXISTS;
+using ::sprintf _LIBCPP_USING_IF_EXISTS;
+using ::sscanf _LIBCPP_USING_IF_EXISTS;
+using ::vfprintf _LIBCPP_USING_IF_EXISTS;
+using ::vfscanf _LIBCPP_USING_IF_EXISTS;
+using ::vsscanf _LIBCPP_USING_IF_EXISTS;
+using ::vsnprintf _LIBCPP_USING_IF_EXISTS;
+using ::vsprintf _LIBCPP_USING_IF_EXISTS;
+using ::fgetc _LIBCPP_USING_IF_EXISTS;
+using ::fgets _LIBCPP_USING_IF_EXISTS;
+using ::fputc _LIBCPP_USING_IF_EXISTS;
+using ::fputs _LIBCPP_USING_IF_EXISTS;
+using ::getc _LIBCPP_USING_IF_EXISTS;
+using ::putc _LIBCPP_USING_IF_EXISTS;
+using ::ungetc _LIBCPP_USING_IF_EXISTS;
+using ::fread _LIBCPP_USING_IF_EXISTS;
+using ::fwrite _LIBCPP_USING_IF_EXISTS;
+#ifndef _LIBCPP_HAS_NO_FGETPOS_FSETPOS
+using ::fgetpos _LIBCPP_USING_IF_EXISTS;
+#endif
+using ::fseek _LIBCPP_USING_IF_EXISTS;
+#ifndef _LIBCPP_HAS_NO_FGETPOS_FSETPOS
+using ::fsetpos _LIBCPP_USING_IF_EXISTS;
+#endif
+using ::ftell _LIBCPP_USING_IF_EXISTS;
+using ::rewind _LIBCPP_USING_IF_EXISTS;
+using ::clearerr _LIBCPP_USING_IF_EXISTS;
+using ::feof _LIBCPP_USING_IF_EXISTS;
+using ::ferror _LIBCPP_USING_IF_EXISTS;
+using ::perror _LIBCPP_USING_IF_EXISTS;
+
+using ::fopen _LIBCPP_USING_IF_EXISTS;
+using ::freopen _LIBCPP_USING_IF_EXISTS;
+using ::remove _LIBCPP_USING_IF_EXISTS;
+using ::rename _LIBCPP_USING_IF_EXISTS;
+using ::tmpfile _LIBCPP_USING_IF_EXISTS;
+using ::tmpnam _LIBCPP_USING_IF_EXISTS;
+
+using ::getchar _LIBCPP_USING_IF_EXISTS;
+#if _LIBCPP_STD_VER <= 11 && !defined(_LIBCPP_C_HAS_NO_GETS)
+using ::gets _LIBCPP_USING_IF_EXISTS;
+#endif
+using ::scanf _LIBCPP_USING_IF_EXISTS;
+using ::vscanf _LIBCPP_USING_IF_EXISTS;
+
+using ::printf _LIBCPP_USING_IF_EXISTS;
+using ::putchar _LIBCPP_USING_IF_EXISTS;
+using ::puts _LIBCPP_USING_IF_EXISTS;
+using ::vprintf _LIBCPP_USING_IF_EXISTS;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CSTDIO
diff --git a/contrib/libs/cxxsupp/libcxx/include/cstdlib b/contrib/libs/cxxsupp/libcxx/include/cstdlib
new file mode 100644
index 00000000000..e1645f636d4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cstdlib
@@ -0,0 +1,151 @@
+// -*- C++ -*-
+//===--------------------------- cstdlib ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CSTDLIB
+#define _LIBCPP_CSTDLIB
+
+/*
+    cstdlib synopsis
+
+Macros:
+
+    EXIT_FAILURE
+    EXIT_SUCCESS
+    MB_CUR_MAX
+    NULL
+    RAND_MAX
+
+namespace std
+{
+
+Types:
+
+    size_t
+    div_t
+    ldiv_t
+    lldiv_t                                                               // C99
+
+double    atof (const char* nptr);
+int       atoi (const char* nptr);
+long      atol (const char* nptr);
+long long atoll(const char* nptr);                                        // C99
+double             strtod  (const char* restrict nptr, char** restrict endptr);
+float              strtof  (const char* restrict nptr, char** restrict endptr); // C99
+long double        strtold (const char* restrict nptr, char** restrict endptr); // C99
+long               strtol  (const char* restrict nptr, char** restrict endptr, int base);
+long long          strtoll (const char* restrict nptr, char** restrict endptr, int base); // C99
+unsigned long      strtoul (const char* restrict nptr, char** restrict endptr, int base);
+unsigned long long strtoull(const char* restrict nptr, char** restrict endptr, int base); // C99
+int rand(void);
+void srand(unsigned int seed);
+void* calloc(size_t nmemb, size_t size);
+void free(void* ptr);
+void* malloc(size_t size);
+void* realloc(void* ptr, size_t size);
+void abort(void);
+int atexit(void (*func)(void));
+void exit(int status);
+void _Exit(int status);
+char* getenv(const char* name);
+int system(const char* string);
+void* bsearch(const void* key, const void* base, size_t nmemb, size_t size,
+              int (*compar)(const void *, const void *));
+void qsort(void* base, size_t nmemb, size_t size,
+           int (*compar)(const void *, const void *));
+int         abs(      int j);
+long        abs(     long j);
+long long   abs(long long j);                                             // C++0X
+long       labs(     long j);
+long long llabs(long long j);                                             // C99
+div_t     div(      int numer,       int denom);
+ldiv_t    div(     long numer,      long denom);
+lldiv_t   div(long long numer, long long denom);                          // C++0X
+ldiv_t   ldiv(     long numer,      long denom);
+lldiv_t lldiv(long long numer, long long denom);                          // C99
+int mblen(const char* s, size_t n);
+int mbtowc(wchar_t* restrict pwc, const char* restrict s, size_t n);
+int wctomb(char* s, wchar_t wchar);
+size_t mbstowcs(wchar_t* restrict pwcs, const char* restrict s, size_t n);
+size_t wcstombs(char* restrict s, const wchar_t* restrict pwcs, size_t n);
+int at_quick_exit(void (*func)(void))                                     // C++11
+void quick_exit(int status);                                              // C++11
+void *aligned_alloc(size_t alignment, size_t size);                       // C11
+
+}  // std
+
+*/
+
+#include <__config>
+#include <stdlib.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef __GNUC__
+#define _LIBCPP_UNREACHABLE() __builtin_unreachable()
+#else
+#define _LIBCPP_UNREACHABLE() _VSTD::abort()
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::size_t _LIBCPP_USING_IF_EXISTS;
+using ::div_t _LIBCPP_USING_IF_EXISTS;
+using ::ldiv_t _LIBCPP_USING_IF_EXISTS;
+using ::lldiv_t _LIBCPP_USING_IF_EXISTS;
+using ::atof _LIBCPP_USING_IF_EXISTS;
+using ::atoi _LIBCPP_USING_IF_EXISTS;
+using ::atol _LIBCPP_USING_IF_EXISTS;
+using ::atoll _LIBCPP_USING_IF_EXISTS;
+using ::strtod _LIBCPP_USING_IF_EXISTS;
+using ::strtof _LIBCPP_USING_IF_EXISTS;
+using ::strtold _LIBCPP_USING_IF_EXISTS;
+using ::strtol _LIBCPP_USING_IF_EXISTS;
+using ::strtoll _LIBCPP_USING_IF_EXISTS;
+using ::strtoul _LIBCPP_USING_IF_EXISTS;
+using ::strtoull _LIBCPP_USING_IF_EXISTS;
+using ::rand _LIBCPP_USING_IF_EXISTS;
+using ::srand _LIBCPP_USING_IF_EXISTS;
+using ::calloc _LIBCPP_USING_IF_EXISTS;
+using ::free _LIBCPP_USING_IF_EXISTS;
+using ::malloc _LIBCPP_USING_IF_EXISTS;
+using ::realloc _LIBCPP_USING_IF_EXISTS;
+using ::abort _LIBCPP_USING_IF_EXISTS;
+using ::atexit _LIBCPP_USING_IF_EXISTS;
+using ::exit _LIBCPP_USING_IF_EXISTS;
+using ::_Exit _LIBCPP_USING_IF_EXISTS;
+#ifndef _LIBCPP_WINDOWS_STORE_APP
+using ::getenv _LIBCPP_USING_IF_EXISTS;
+using ::system _LIBCPP_USING_IF_EXISTS;
+#endif
+using ::bsearch _LIBCPP_USING_IF_EXISTS;
+using ::qsort _LIBCPP_USING_IF_EXISTS;
+using ::abs _LIBCPP_USING_IF_EXISTS;
+using ::labs _LIBCPP_USING_IF_EXISTS;
+using ::llabs _LIBCPP_USING_IF_EXISTS;
+using ::div _LIBCPP_USING_IF_EXISTS;
+using ::ldiv _LIBCPP_USING_IF_EXISTS;
+using ::lldiv _LIBCPP_USING_IF_EXISTS;
+using ::mblen _LIBCPP_USING_IF_EXISTS;
+using ::mbtowc _LIBCPP_USING_IF_EXISTS;
+using ::wctomb _LIBCPP_USING_IF_EXISTS;
+using ::mbstowcs _LIBCPP_USING_IF_EXISTS;
+using ::wcstombs _LIBCPP_USING_IF_EXISTS;
+#if !defined(_LIBCPP_CXX03_LANG) && defined(_LIBCPP_HAS_QUICK_EXIT)
+using ::at_quick_exit _LIBCPP_USING_IF_EXISTS;
+using ::quick_exit _LIBCPP_USING_IF_EXISTS;
+#endif
+#if _LIBCPP_STD_VER > 14 && defined(_LIBCPP_HAS_ALIGNED_ALLOC)
+using ::aligned_alloc _LIBCPP_USING_IF_EXISTS;
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CSTDLIB
diff --git a/contrib/libs/cxxsupp/libcxx/include/cstring b/contrib/libs/cxxsupp/libcxx/include/cstring
new file mode 100644
index 00000000000..d69d27c1a9f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cstring
@@ -0,0 +1,94 @@
+// -*- C++ -*-
+//===--------------------------- cstring ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CSTRING
+#define _LIBCPP_CSTRING
+
+/*
+    cstring synopsis
+
+Macros:
+
+    NULL
+
+namespace std
+{
+
+Types:
+
+    size_t
+
+void* memcpy(void* restrict s1, const void* restrict s2, size_t n);
+void* memmove(void* s1, const void* s2, size_t n);
+char* strcpy (char* restrict s1, const char* restrict s2);
+char* strncpy(char* restrict s1, const char* restrict s2, size_t n);
+char* strcat (char* restrict s1, const char* restrict s2);
+char* strncat(char* restrict s1, const char* restrict s2, size_t n);
+int memcmp(const void* s1, const void* s2, size_t n);
+int strcmp (const char* s1, const char* s2);
+int strncmp(const char* s1, const char* s2, size_t n);
+int strcoll(const char* s1, const char* s2);
+size_t strxfrm(char* restrict s1, const char* restrict s2, size_t n);
+const void* memchr(const void* s, int c, size_t n);
+      void* memchr(      void* s, int c, size_t n);
+const char* strchr(const char* s, int c);
+      char* strchr(      char* s, int c);
+size_t strcspn(const char* s1, const char* s2);
+const char* strpbrk(const char* s1, const char* s2);
+      char* strpbrk(      char* s1, const char* s2);
+const char* strrchr(const char* s, int c);
+      char* strrchr(      char* s, int c);
+size_t strspn(const char* s1, const char* s2);
+const char* strstr(const char* s1, const char* s2);
+      char* strstr(      char* s1, const char* s2);
+char* strtok(char* restrict s1, const char* restrict s2);
+void* memset(void* s, int c, size_t n);
+char* strerror(int errnum);
+size_t strlen(const char* s);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <string.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::size_t _LIBCPP_USING_IF_EXISTS;
+using ::memcpy _LIBCPP_USING_IF_EXISTS;
+using ::memmove _LIBCPP_USING_IF_EXISTS;
+using ::strcpy _LIBCPP_USING_IF_EXISTS;
+using ::strncpy _LIBCPP_USING_IF_EXISTS;
+using ::strcat _LIBCPP_USING_IF_EXISTS;
+using ::strncat _LIBCPP_USING_IF_EXISTS;
+using ::memcmp _LIBCPP_USING_IF_EXISTS;
+using ::strcmp _LIBCPP_USING_IF_EXISTS;
+using ::strncmp _LIBCPP_USING_IF_EXISTS;
+using ::strcoll _LIBCPP_USING_IF_EXISTS;
+using ::strxfrm _LIBCPP_USING_IF_EXISTS;
+using ::memchr _LIBCPP_USING_IF_EXISTS;
+using ::strchr _LIBCPP_USING_IF_EXISTS;
+using ::strcspn _LIBCPP_USING_IF_EXISTS;
+using ::strpbrk _LIBCPP_USING_IF_EXISTS;
+using ::strrchr _LIBCPP_USING_IF_EXISTS;
+using ::strspn _LIBCPP_USING_IF_EXISTS;
+using ::strstr _LIBCPP_USING_IF_EXISTS;
+using ::strtok _LIBCPP_USING_IF_EXISTS;
+using ::memset _LIBCPP_USING_IF_EXISTS;
+using ::strerror _LIBCPP_USING_IF_EXISTS;
+using ::strlen _LIBCPP_USING_IF_EXISTS;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CSTRING
diff --git a/contrib/libs/cxxsupp/libcxx/include/ctgmath b/contrib/libs/cxxsupp/libcxx/include/ctgmath
new file mode 100644
index 00000000000..41f7f0a172e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/ctgmath
@@ -0,0 +1,28 @@
+// -*- C++ -*-
+//===-------------------------- ctgmath -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CTGMATH
+#define _LIBCPP_CTGMATH
+
+/*
+    ctgmath synopsis
+
+#include <ccomplex>
+#include <cmath>
+
+*/
+
+#include <ccomplex>
+#include <cmath>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#endif // _LIBCPP_CTGMATH
diff --git a/contrib/libs/cxxsupp/libcxx/include/ctime b/contrib/libs/cxxsupp/libcxx/include/ctime
new file mode 100644
index 00000000000..816618f6a37
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/ctime
@@ -0,0 +1,93 @@
+// -*- C++ -*-
+//===---------------------------- ctime -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CTIME
+#define _LIBCPP_CTIME
+
+/*
+    ctime synopsis
+
+Macros:
+
+    NULL
+    CLOCKS_PER_SEC
+    TIME_UTC // C++17
+
+namespace std
+{
+
+Types:
+
+    clock_t
+    size_t
+    time_t
+    tm
+    timespec // C++17
+
+clock_t clock();
+double difftime(time_t time1, time_t time0);
+time_t mktime(tm* timeptr);
+time_t time(time_t* timer);
+char* asctime(const tm* timeptr);
+char* ctime(const time_t* timer);
+tm*    gmtime(const time_t* timer);
+tm* localtime(const time_t* timer);
+size_t strftime(char* restrict s, size_t maxsize, const char* restrict format,
+                const tm* restrict timeptr);
+int timespec_get( struct timespec *ts, int base); // C++17
+}  // std
+
+*/
+
+#include <__config>
+#include <time.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+// FIXME:
+// Apple SDKs don't define ::timespec_get unconditionally in C++ mode. This
+// should be fixed in future SDKs, but for the time being we need to avoid
+// trying to use that declaration when the SDK doesn't provide it. Note that
+// we're detecting this here instead of in <__config> because we can't include
+// system headers from <__config>, since it leads to circular module dependencies.
+// This is also meant to be a very temporary workaround until the SDKs are fixed.
+#if defined(__APPLE__) && !__has_attribute(using_if_exists)
+#   include <sys/cdefs.h>
+#   if defined(_LIBCPP_HAS_TIMESPEC_GET) && (__DARWIN_C_LEVEL < __DARWIN_C_FULL)
+#       define _LIBCPP_HAS_TIMESPEC_GET_NOT_ACTUALLY_PROVIDED
+#   endif
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::clock_t _LIBCPP_USING_IF_EXISTS;
+using ::size_t _LIBCPP_USING_IF_EXISTS;
+using ::time_t _LIBCPP_USING_IF_EXISTS;
+using ::tm _LIBCPP_USING_IF_EXISTS;
+#if _LIBCPP_STD_VER > 14 && defined(_LIBCPP_HAS_TIMESPEC_GET)
+using ::timespec _LIBCPP_USING_IF_EXISTS;
+#endif
+using ::clock _LIBCPP_USING_IF_EXISTS;
+using ::difftime _LIBCPP_USING_IF_EXISTS;
+using ::mktime _LIBCPP_USING_IF_EXISTS;
+using ::time _LIBCPP_USING_IF_EXISTS;
+using ::asctime _LIBCPP_USING_IF_EXISTS;
+using ::ctime _LIBCPP_USING_IF_EXISTS;
+using ::gmtime _LIBCPP_USING_IF_EXISTS;
+using ::localtime _LIBCPP_USING_IF_EXISTS;
+using ::strftime _LIBCPP_USING_IF_EXISTS;
+#if _LIBCPP_STD_VER > 14 && defined(_LIBCPP_HAS_TIMESPEC_GET) && !defined(_LIBCPP_HAS_TIMESPEC_GET_NOT_ACTUALLY_PROVIDED)
+using ::timespec_get _LIBCPP_USING_IF_EXISTS;
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CTIME
diff --git a/contrib/libs/cxxsupp/libcxx/include/ctype.h b/contrib/libs/cxxsupp/libcxx/include/ctype.h
new file mode 100644
index 00000000000..e64c643477b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/ctype.h
@@ -0,0 +1,63 @@
+// -*- C++ -*-
+//===---------------------------- ctype.h ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CTYPE_H
+#define _LIBCPP_CTYPE_H
+
+/*
+    ctype.h synopsis
+
+int isalnum(int c);
+int isalpha(int c);
+int isblank(int c);  // C99
+int iscntrl(int c);
+int isdigit(int c);
+int isgraph(int c);
+int islower(int c);
+int isprint(int c);
+int ispunct(int c);
+int isspace(int c);
+int isupper(int c);
+int isxdigit(int c);
+int tolower(int c);
+int toupper(int c);
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(ctype.h)
+#else
+#include_next <ctype.h>
+#endif
+
+#ifdef __cplusplus
+
+#undef isalnum
+#undef isalpha
+#undef isblank
+#undef iscntrl
+#undef isdigit
+#undef isgraph
+#undef islower
+#undef isprint
+#undef ispunct
+#undef isspace
+#undef isupper
+#undef isxdigit
+#undef tolower
+#undef toupper
+
+#endif
+
+#endif // _LIBCPP_CTYPE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/cwchar b/contrib/libs/cxxsupp/libcxx/include/cwchar
new file mode 100644
index 00000000000..c596398d3e0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cwchar
@@ -0,0 +1,184 @@
+// -*- C++ -*-
+//===--------------------------- cwchar -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CWCHAR
+#define _LIBCPP_CWCHAR
+
+/*
+    cwchar synopsis
+
+Macros:
+
+    NULL
+    WCHAR_MAX
+    WCHAR_MIN
+    WEOF
+
+namespace std
+{
+
+Types:
+
+    mbstate_t
+    size_t
+    tm
+    wint_t
+
+int fwprintf(FILE* restrict stream, const wchar_t* restrict format, ...);
+int fwscanf(FILE* restrict stream, const wchar_t* restrict format, ...);
+int swprintf(wchar_t* restrict s, size_t n, const wchar_t* restrict format, ...);
+int swscanf(const wchar_t* restrict s, const wchar_t* restrict format, ...);
+int vfwprintf(FILE* restrict stream, const wchar_t* restrict format, va_list arg);
+int vfwscanf(FILE* restrict stream, const wchar_t* restrict format, va_list arg);  // C99
+int vswprintf(wchar_t* restrict s, size_t n, const wchar_t* restrict format, va_list arg);
+int vswscanf(const wchar_t* restrict s, const wchar_t* restrict format, va_list arg);  // C99
+int vwprintf(const wchar_t* restrict format, va_list arg);
+int vwscanf(const wchar_t* restrict format, va_list arg);  // C99
+int wprintf(const wchar_t* restrict format, ...);
+int wscanf(const wchar_t* restrict format, ...);
+wint_t fgetwc(FILE* stream);
+wchar_t* fgetws(wchar_t* restrict s, int n, FILE* restrict stream);
+wint_t fputwc(wchar_t c, FILE* stream);
+int fputws(const wchar_t* restrict s, FILE* restrict stream);
+int fwide(FILE* stream, int mode);
+wint_t getwc(FILE* stream);
+wint_t getwchar();
+wint_t putwc(wchar_t c, FILE* stream);
+wint_t putwchar(wchar_t c);
+wint_t ungetwc(wint_t c, FILE* stream);
+double wcstod(const wchar_t* restrict nptr, wchar_t** restrict endptr);
+float wcstof(const wchar_t* restrict nptr, wchar_t** restrict endptr);         // C99
+long double wcstold(const wchar_t* restrict nptr, wchar_t** restrict endptr);  // C99
+long wcstol(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);
+long long wcstoll(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);  // C99
+unsigned long wcstoul(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);
+unsigned long long wcstoull(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);  // C99
+wchar_t* wcscpy(wchar_t* restrict s1, const wchar_t* restrict s2);
+wchar_t* wcsncpy(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+wchar_t* wcscat(wchar_t* restrict s1, const wchar_t* restrict s2);
+wchar_t* wcsncat(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+int wcscmp(const wchar_t* s1, const wchar_t* s2);
+int wcscoll(const wchar_t* s1, const wchar_t* s2);
+int wcsncmp(const wchar_t* s1, const wchar_t* s2, size_t n);
+size_t wcsxfrm(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+const wchar_t* wcschr(const wchar_t* s, wchar_t c);
+      wchar_t* wcschr(      wchar_t* s, wchar_t c);
+size_t wcscspn(const wchar_t* s1, const wchar_t* s2);
+size_t wcslen(const wchar_t* s);
+const wchar_t* wcspbrk(const wchar_t* s1, const wchar_t* s2);
+      wchar_t* wcspbrk(      wchar_t* s1, const wchar_t* s2);
+const wchar_t* wcsrchr(const wchar_t* s, wchar_t c);
+      wchar_t* wcsrchr(      wchar_t* s, wchar_t c);
+size_t wcsspn(const wchar_t* s1, const wchar_t* s2);
+const wchar_t* wcsstr(const wchar_t* s1, const wchar_t* s2);
+      wchar_t* wcsstr(      wchar_t* s1, const wchar_t* s2);
+wchar_t* wcstok(wchar_t* restrict s1, const wchar_t* restrict s2, wchar_t** restrict ptr);
+const wchar_t* wmemchr(const wchar_t* s, wchar_t c, size_t n);
+      wchar_t* wmemchr(      wchar_t* s, wchar_t c, size_t n);
+int wmemcmp(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+wchar_t* wmemcpy(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+wchar_t* wmemmove(wchar_t* s1, const wchar_t* s2, size_t n);
+wchar_t* wmemset(wchar_t* s, wchar_t c, size_t n);
+size_t wcsftime(wchar_t* restrict s, size_t maxsize, const wchar_t* restrict format,
+                const tm* restrict timeptr);
+wint_t btowc(int c);
+int wctob(wint_t c);
+int mbsinit(const mbstate_t* ps);
+size_t mbrlen(const char* restrict s, size_t n, mbstate_t* restrict ps);
+size_t mbrtowc(wchar_t* restrict pwc, const char* restrict s, size_t n, mbstate_t* restrict ps);
+size_t wcrtomb(char* restrict s, wchar_t wc, mbstate_t* restrict ps);
+size_t mbsrtowcs(wchar_t* restrict dst, const char** restrict src, size_t len,
+                 mbstate_t* restrict ps);
+size_t wcsrtombs(char* restrict dst, const wchar_t** restrict src, size_t len,
+                 mbstate_t* restrict ps);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <cwctype>
+#include <wchar.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+using ::mbstate_t _LIBCPP_USING_IF_EXISTS;
+using ::size_t _LIBCPP_USING_IF_EXISTS;
+using ::tm _LIBCPP_USING_IF_EXISTS;
+using ::wint_t _LIBCPP_USING_IF_EXISTS;
+using ::FILE _LIBCPP_USING_IF_EXISTS;
+using ::fwprintf _LIBCPP_USING_IF_EXISTS;
+using ::fwscanf _LIBCPP_USING_IF_EXISTS;
+using ::swprintf _LIBCPP_USING_IF_EXISTS;
+using ::vfwprintf _LIBCPP_USING_IF_EXISTS;
+using ::vswprintf _LIBCPP_USING_IF_EXISTS;
+using ::swscanf _LIBCPP_USING_IF_EXISTS;
+using ::vfwscanf _LIBCPP_USING_IF_EXISTS;
+using ::vswscanf _LIBCPP_USING_IF_EXISTS;
+using ::fgetwc _LIBCPP_USING_IF_EXISTS;
+using ::fgetws _LIBCPP_USING_IF_EXISTS;
+using ::fputwc _LIBCPP_USING_IF_EXISTS;
+using ::fputws _LIBCPP_USING_IF_EXISTS;
+using ::fwide _LIBCPP_USING_IF_EXISTS;
+using ::getwc _LIBCPP_USING_IF_EXISTS;
+using ::putwc _LIBCPP_USING_IF_EXISTS;
+using ::ungetwc _LIBCPP_USING_IF_EXISTS;
+using ::wcstod _LIBCPP_USING_IF_EXISTS;
+using ::wcstof _LIBCPP_USING_IF_EXISTS;
+using ::wcstold _LIBCPP_USING_IF_EXISTS;
+using ::wcstol _LIBCPP_USING_IF_EXISTS;
+using ::wcstoll _LIBCPP_USING_IF_EXISTS;
+using ::wcstoul _LIBCPP_USING_IF_EXISTS;
+using ::wcstoull _LIBCPP_USING_IF_EXISTS;
+using ::wcscpy _LIBCPP_USING_IF_EXISTS;
+using ::wcsncpy _LIBCPP_USING_IF_EXISTS;
+using ::wcscat _LIBCPP_USING_IF_EXISTS;
+using ::wcsncat _LIBCPP_USING_IF_EXISTS;
+using ::wcscmp _LIBCPP_USING_IF_EXISTS;
+using ::wcscoll _LIBCPP_USING_IF_EXISTS;
+using ::wcsncmp _LIBCPP_USING_IF_EXISTS;
+using ::wcsxfrm _LIBCPP_USING_IF_EXISTS;
+using ::wcschr _LIBCPP_USING_IF_EXISTS;
+using ::wcspbrk _LIBCPP_USING_IF_EXISTS;
+using ::wcsrchr _LIBCPP_USING_IF_EXISTS;
+using ::wcsstr _LIBCPP_USING_IF_EXISTS;
+using ::wmemchr _LIBCPP_USING_IF_EXISTS;
+using ::wcscspn _LIBCPP_USING_IF_EXISTS;
+using ::wcslen _LIBCPP_USING_IF_EXISTS;
+using ::wcsspn _LIBCPP_USING_IF_EXISTS;
+using ::wcstok _LIBCPP_USING_IF_EXISTS;
+using ::wmemcmp _LIBCPP_USING_IF_EXISTS;
+using ::wmemcpy _LIBCPP_USING_IF_EXISTS;
+using ::wmemmove _LIBCPP_USING_IF_EXISTS;
+using ::wmemset _LIBCPP_USING_IF_EXISTS;
+using ::wcsftime _LIBCPP_USING_IF_EXISTS;
+using ::btowc _LIBCPP_USING_IF_EXISTS;
+using ::wctob _LIBCPP_USING_IF_EXISTS;
+using ::mbsinit _LIBCPP_USING_IF_EXISTS;
+using ::mbrlen _LIBCPP_USING_IF_EXISTS;
+using ::mbrtowc _LIBCPP_USING_IF_EXISTS;
+using ::wcrtomb _LIBCPP_USING_IF_EXISTS;
+using ::mbsrtowcs _LIBCPP_USING_IF_EXISTS;
+using ::wcsrtombs _LIBCPP_USING_IF_EXISTS;
+
+using ::getwchar _LIBCPP_USING_IF_EXISTS;
+using ::vwscanf _LIBCPP_USING_IF_EXISTS;
+using ::wscanf _LIBCPP_USING_IF_EXISTS;
+
+using ::putwchar _LIBCPP_USING_IF_EXISTS;
+using ::vwprintf _LIBCPP_USING_IF_EXISTS;
+using ::wprintf _LIBCPP_USING_IF_EXISTS;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CWCHAR
diff --git a/contrib/libs/cxxsupp/libcxx/include/cwctype b/contrib/libs/cxxsupp/libcxx/include/cwctype
new file mode 100644
index 00000000000..27eea2f1573
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cwctype
@@ -0,0 +1,88 @@
+// -*- C++ -*-
+//===--------------------------- cwctype ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CWCTYPE
+#define _LIBCPP_CWCTYPE
+
+/*
+    cwctype synopsis
+
+Macros:
+
+    WEOF
+
+namespace std
+{
+
+Types:
+
+    wint_t
+    wctrans_t
+    wctype_t
+
+int iswalnum(wint_t wc);
+int iswalpha(wint_t wc);
+int iswblank(wint_t wc);  // C99
+int iswcntrl(wint_t wc);
+int iswdigit(wint_t wc);
+int iswgraph(wint_t wc);
+int iswlower(wint_t wc);
+int iswprint(wint_t wc);
+int iswpunct(wint_t wc);
+int iswspace(wint_t wc);
+int iswupper(wint_t wc);
+int iswxdigit(wint_t wc);
+int iswctype(wint_t wc, wctype_t desc);
+wctype_t wctype(const char* property);
+wint_t towlower(wint_t wc);
+wint_t towupper(wint_t wc);
+wint_t towctrans(wint_t wc, wctrans_t desc);
+wctrans_t wctrans(const char* property);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <cctype>
+#include <wctype.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if defined(_LIBCPP_INCLUDED_C_LIBRARY_WCTYPE_H)
+using ::wint_t _LIBCPP_USING_IF_EXISTS;
+using ::wctrans_t _LIBCPP_USING_IF_EXISTS;
+using ::wctype_t _LIBCPP_USING_IF_EXISTS;
+using ::iswalnum _LIBCPP_USING_IF_EXISTS;
+using ::iswalpha _LIBCPP_USING_IF_EXISTS;
+using ::iswblank _LIBCPP_USING_IF_EXISTS;
+using ::iswcntrl _LIBCPP_USING_IF_EXISTS;
+using ::iswdigit _LIBCPP_USING_IF_EXISTS;
+using ::iswgraph _LIBCPP_USING_IF_EXISTS;
+using ::iswlower _LIBCPP_USING_IF_EXISTS;
+using ::iswprint _LIBCPP_USING_IF_EXISTS;
+using ::iswpunct _LIBCPP_USING_IF_EXISTS;
+using ::iswspace _LIBCPP_USING_IF_EXISTS;
+using ::iswupper _LIBCPP_USING_IF_EXISTS;
+using ::iswxdigit _LIBCPP_USING_IF_EXISTS;
+using ::iswctype _LIBCPP_USING_IF_EXISTS;
+using ::wctype _LIBCPP_USING_IF_EXISTS;
+using ::towlower _LIBCPP_USING_IF_EXISTS;
+using ::towupper _LIBCPP_USING_IF_EXISTS;
+using ::towctrans _LIBCPP_USING_IF_EXISTS;
+using ::wctrans _LIBCPP_USING_IF_EXISTS;
+#endif // _LIBCPP_INCLUDED_C_LIBRARY_WCTYPE_H
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_CWCTYPE
diff --git a/contrib/libs/cxxsupp/libcxx/include/cxxabi.h b/contrib/libs/cxxsupp/libcxx/include/cxxabi.h
new file mode 100644
index 00000000000..b4eb4edf18b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/cxxabi.h
@@ -0,0 +1,7 @@
+#pragma once
+
+#if defined(__IOS__) || defined(__ANDROID__)
+#include_next <cxxabi.h>
+#else
+#include <contrib/libs/cxxsupp/libcxxrt/cxxabi.h>
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/include/deque b/contrib/libs/cxxsupp/libcxx/include/deque
new file mode 100644
index 00000000000..67cd6654f13
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/deque
@@ -0,0 +1,3030 @@
+// -*- C++ -*-
+//===---------------------------- deque -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_DEQUE
+#define _LIBCPP_DEQUE
+
+/*
+    deque synopsis
+
+namespace std
+{
+
+template <class T, class Allocator = allocator<T> >
+class deque
+{
+public:
+    // types:
+    typedef T value_type;
+    typedef Allocator allocator_type;
+
+    typedef typename allocator_type::reference       reference;
+    typedef typename allocator_type::const_reference const_reference;
+    typedef implementation-defined                   iterator;
+    typedef implementation-defined                   const_iterator;
+    typedef typename allocator_type::size_type       size_type;
+    typedef typename allocator_type::difference_type difference_type;
+
+    typedef typename allocator_type::pointer         pointer;
+    typedef typename allocator_type::const_pointer   const_pointer;
+    typedef std::reverse_iterator<iterator>          reverse_iterator;
+    typedef std::reverse_iterator<const_iterator>    const_reverse_iterator;
+
+    // construct/copy/destroy:
+    deque() noexcept(is_nothrow_default_constructible<allocator_type>::value);
+    explicit deque(const allocator_type& a);
+    explicit deque(size_type n);
+    explicit deque(size_type n, const allocator_type& a); // C++14
+    deque(size_type n, const value_type& v);
+    deque(size_type n, const value_type& v, const allocator_type& a);
+    template <class InputIterator>
+        deque(InputIterator f, InputIterator l);
+    template <class InputIterator>
+        deque(InputIterator f, InputIterator l, const allocator_type& a);
+    deque(const deque& c);
+    deque(deque&& c)
+        noexcept(is_nothrow_move_constructible<allocator_type>::value);
+    deque(initializer_list<value_type> il, const Allocator& a = allocator_type());
+    deque(const deque& c, const allocator_type& a);
+    deque(deque&& c, const allocator_type& a);
+    ~deque();
+
+    deque& operator=(const deque& c);
+    deque& operator=(deque&& c)
+        noexcept(
+             allocator_type::propagate_on_container_move_assignment::value &&
+             is_nothrow_move_assignable<allocator_type>::value);
+    deque& operator=(initializer_list<value_type> il);
+
+    template <class InputIterator>
+        void assign(InputIterator f, InputIterator l);
+    void assign(size_type n, const value_type& v);
+    void assign(initializer_list<value_type> il);
+
+    allocator_type get_allocator() const noexcept;
+
+    // iterators:
+
+    iterator       begin() noexcept;
+    const_iterator begin() const noexcept;
+    iterator       end() noexcept;
+    const_iterator end() const noexcept;
+
+    reverse_iterator       rbegin() noexcept;
+    const_reverse_iterator rbegin() const noexcept;
+    reverse_iterator       rend() noexcept;
+    const_reverse_iterator rend() const noexcept;
+
+    const_iterator         cbegin() const noexcept;
+    const_iterator         cend() const noexcept;
+    const_reverse_iterator crbegin() const noexcept;
+    const_reverse_iterator crend() const noexcept;
+
+    // capacity:
+    size_type size() const noexcept;
+    size_type max_size() const noexcept;
+    void resize(size_type n);
+    void resize(size_type n, const value_type& v);
+    void shrink_to_fit();
+    bool empty() const noexcept;
+
+    // element access:
+    reference operator[](size_type i);
+    const_reference operator[](size_type i) const;
+    reference at(size_type i);
+    const_reference at(size_type i) const;
+    reference front();
+    const_reference front() const;
+    reference back();
+    const_reference back() const;
+
+    // modifiers:
+    void push_front(const value_type& v);
+    void push_front(value_type&& v);
+    void push_back(const value_type& v);
+    void push_back(value_type&& v);
+    template <class... Args> reference emplace_front(Args&&... args);  // reference in C++17
+    template <class... Args> reference emplace_back(Args&&... args);   // reference in C++17
+    template <class... Args> iterator emplace(const_iterator p, Args&&... args);
+    iterator insert(const_iterator p, const value_type& v);
+    iterator insert(const_iterator p, value_type&& v);
+    iterator insert(const_iterator p, size_type n, const value_type& v);
+    template <class InputIterator>
+        iterator insert(const_iterator p, InputIterator f, InputIterator l);
+    iterator insert(const_iterator p, initializer_list<value_type> il);
+    void pop_front();
+    void pop_back();
+    iterator erase(const_iterator p);
+    iterator erase(const_iterator f, const_iterator l);
+    void swap(deque& c)
+        noexcept(allocator_traits<allocator_type>::is_always_equal::value);  // C++17
+    void clear() noexcept;
+};
+
+template <class InputIterator, class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
+   deque(InputIterator, InputIterator, Allocator = Allocator())
+   -> deque<typename iterator_traits<InputIterator>::value_type, Allocator>;
+
+template <class T, class Allocator>
+    bool operator==(const deque<T,Allocator>& x, const deque<T,Allocator>& y);
+template <class T, class Allocator>
+    bool operator< (const deque<T,Allocator>& x, const deque<T,Allocator>& y);
+template <class T, class Allocator>
+    bool operator!=(const deque<T,Allocator>& x, const deque<T,Allocator>& y);
+template <class T, class Allocator>
+    bool operator> (const deque<T,Allocator>& x, const deque<T,Allocator>& y);
+template <class T, class Allocator>
+    bool operator>=(const deque<T,Allocator>& x, const deque<T,Allocator>& y);
+template <class T, class Allocator>
+    bool operator<=(const deque<T,Allocator>& x, const deque<T,Allocator>& y);
+
+// specialized algorithms:
+template <class T, class Allocator>
+    void swap(deque<T,Allocator>& x, deque<T,Allocator>& y)
+         noexcept(noexcept(x.swap(y)));
+
+template <class T, class Allocator, class U>
+    typename deque<T, Allocator>::size_type
+    erase(deque<T, Allocator>& c, const U& value);       // C++20
+template <class T, class Allocator, class Predicate>
+    typename deque<T, Allocator>::size_type
+    erase_if(deque<T, Allocator>& c, Predicate pred);    // C++20
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__split_buffer>
+#include <__utility/forward.h>
+#include <algorithm>
+#include <compare>
+#include <initializer_list>
+#include <iterator>
+#include <limits>
+#include <stdexcept>
+#include <type_traits>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class _Allocator> class __deque_base;
+template <class _Tp, class _Allocator = allocator<_Tp> > class _LIBCPP_TEMPLATE_VIS deque;
+
+template <class _ValueType, class _Pointer, class _Reference, class _MapPointer,
+          class _DiffType, _DiffType _BlockSize>
+class _LIBCPP_TEMPLATE_VIS __deque_iterator;
+
+template <class _RAIter,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+copy(_RAIter __f,
+     _RAIter __l,
+     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
+     typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type* = 0);
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _OutputIterator>
+_OutputIterator
+copy(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+     _OutputIterator __r);
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+copy(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
+
+template <class _RAIter,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+copy_backward(_RAIter __f,
+              _RAIter __l,
+              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
+              typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type* = 0);
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _OutputIterator>
+_OutputIterator
+copy_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+              _OutputIterator __r);
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+copy_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
+
+template <class _RAIter,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+move(_RAIter __f,
+     _RAIter __l,
+     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
+     typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type* = 0);
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _OutputIterator>
+_OutputIterator
+move(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+     _OutputIterator __r);
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+move(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
+
+template <class _RAIter,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+move_backward(_RAIter __f,
+              _RAIter __l,
+              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
+              typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type* = 0);
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _OutputIterator>
+_OutputIterator
+move_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+              _OutputIterator __r);
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+move_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
+
+template <class _ValueType, class _DiffType>
+struct __deque_block_size {
+  static const _DiffType __buf_size = 64 * sizeof(void*);
+  static const _DiffType value = (__buf_size / sizeof(_ValueType)) > 2 ? (__buf_size / sizeof(_ValueType)) : 2;
+  //static const _DiffType value = sizeof(_ValueType) < 256 ? 4096 / sizeof(_ValueType) : 16;
+};
+
+template <class _ValueType, class _Pointer, class _Reference, class _MapPointer,
+          class _DiffType, _DiffType _BS =
+#ifdef _LIBCPP_ABI_INCOMPLETE_TYPES_IN_DEQUE
+// Keep template parameter to avoid changing all template declarations thoughout
+// this file.
+                               0
+#else
+                               __deque_block_size<_ValueType, _DiffType>::value
+#endif
+          >
+class _LIBCPP_TEMPLATE_VIS __deque_iterator
+{
+    typedef _MapPointer __map_iterator;
+public:
+    typedef _Pointer  pointer;
+    typedef _DiffType difference_type;
+private:
+    __map_iterator __m_iter_;
+    pointer        __ptr_;
+
+    static const difference_type __block_size;
+public:
+    typedef _ValueType                  value_type;
+    typedef random_access_iterator_tag  iterator_category;
+    typedef _Reference                  reference;
+
+    _LIBCPP_INLINE_VISIBILITY __deque_iterator() _NOEXCEPT
+#if _LIBCPP_STD_VER > 11
+     : __m_iter_(nullptr), __ptr_(nullptr)
+#endif
+     {}
+
+    template <class _Pp, class _Rp, class _MP>
+    _LIBCPP_INLINE_VISIBILITY
+    __deque_iterator(const __deque_iterator<value_type, _Pp, _Rp, _MP, difference_type, _BS>& __it,
+                typename enable_if<is_convertible<_Pp, pointer>::value>::type* = 0) _NOEXCEPT
+        : __m_iter_(__it.__m_iter_), __ptr_(__it.__ptr_) {}
+
+    _LIBCPP_INLINE_VISIBILITY reference operator*() const {return *__ptr_;}
+    _LIBCPP_INLINE_VISIBILITY pointer operator->() const {return __ptr_;}
+
+    _LIBCPP_INLINE_VISIBILITY __deque_iterator& operator++()
+    {
+        if (++__ptr_ - *__m_iter_ == __block_size)
+        {
+            ++__m_iter_;
+            __ptr_ = *__m_iter_;
+        }
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __deque_iterator operator++(int)
+    {
+        __deque_iterator __tmp = *this;
+        ++(*this);
+        return __tmp;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __deque_iterator& operator--()
+    {
+        if (__ptr_ == *__m_iter_)
+        {
+            --__m_iter_;
+            __ptr_ = *__m_iter_ + __block_size;
+        }
+        --__ptr_;
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __deque_iterator operator--(int)
+    {
+        __deque_iterator __tmp = *this;
+        --(*this);
+        return __tmp;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __deque_iterator& operator+=(difference_type __n)
+    {
+        if (__n != 0)
+        {
+            __n += __ptr_ - *__m_iter_;
+            if (__n > 0)
+            {
+                __m_iter_ += __n / __block_size;
+                __ptr_ = *__m_iter_ + __n % __block_size;
+            }
+            else // (__n < 0)
+            {
+                difference_type __z = __block_size - 1 - __n;
+                __m_iter_ -= __z / __block_size;
+                __ptr_ = *__m_iter_ + (__block_size - 1 - __z % __block_size);
+            }
+        }
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __deque_iterator& operator-=(difference_type __n)
+    {
+        return *this += -__n;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __deque_iterator operator+(difference_type __n) const
+    {
+        __deque_iterator __t(*this);
+        __t += __n;
+        return __t;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY __deque_iterator operator-(difference_type __n) const
+    {
+        __deque_iterator __t(*this);
+        __t -= __n;
+        return __t;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    friend __deque_iterator operator+(difference_type __n, const __deque_iterator& __it)
+        {return __it + __n;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    friend difference_type operator-(const __deque_iterator& __x, const __deque_iterator& __y)
+    {
+        if (__x != __y)
+            return (__x.__m_iter_ - __y.__m_iter_) * __block_size
+                 + (__x.__ptr_ - *__x.__m_iter_)
+                 - (__y.__ptr_ - *__y.__m_iter_);
+        return 0;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY reference operator[](difference_type __n) const
+        {return *(*this + __n);}
+
+    _LIBCPP_INLINE_VISIBILITY friend
+        bool operator==(const __deque_iterator& __x, const __deque_iterator& __y)
+        {return __x.__ptr_ == __y.__ptr_;}
+
+    _LIBCPP_INLINE_VISIBILITY friend
+        bool operator!=(const __deque_iterator& __x, const __deque_iterator& __y)
+        {return !(__x == __y);}
+
+    _LIBCPP_INLINE_VISIBILITY friend
+        bool operator<(const __deque_iterator& __x, const __deque_iterator& __y)
+        {return __x.__m_iter_ < __y.__m_iter_ ||
+               (__x.__m_iter_ == __y.__m_iter_ && __x.__ptr_ < __y.__ptr_);}
+
+    _LIBCPP_INLINE_VISIBILITY friend
+        bool operator>(const __deque_iterator& __x, const __deque_iterator& __y)
+        {return __y < __x;}
+
+    _LIBCPP_INLINE_VISIBILITY friend
+        bool operator<=(const __deque_iterator& __x, const __deque_iterator& __y)
+        {return !(__y < __x);}
+
+    _LIBCPP_INLINE_VISIBILITY friend
+        bool operator>=(const __deque_iterator& __x, const __deque_iterator& __y)
+        {return !(__x < __y);}
+
+private:
+    _LIBCPP_INLINE_VISIBILITY __deque_iterator(__map_iterator __m, pointer __p) _NOEXCEPT
+        : __m_iter_(__m), __ptr_(__p) {}
+
+    template <class _Tp, class _Ap> friend class __deque_base;
+    template <class _Tp, class _Ap> friend class _LIBCPP_TEMPLATE_VIS deque;
+    template <class _Vp, class _Pp, class _Rp, class _MP, class _Dp, _Dp>
+        friend class _LIBCPP_TEMPLATE_VIS __deque_iterator;
+
+    template <class _RAIter,
+              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+    friend
+    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+    copy(_RAIter __f,
+         _RAIter __l,
+         __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
+         typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*);
+
+    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+              class _OutputIterator>
+    friend
+    _OutputIterator
+    copy(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+         __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+         _OutputIterator __r);
+
+    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+    friend
+    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+    copy(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+         __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+         __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
+
+    template <class _RAIter,
+              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+    friend
+    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+    copy_backward(_RAIter __f,
+                  _RAIter __l,
+                  __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
+                  typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*);
+
+    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+              class _OutputIterator>
+    friend
+    _OutputIterator
+    copy_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+                  __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+                  _OutputIterator __r);
+
+    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+    friend
+    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+    copy_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+                  __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+                  __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
+
+    template <class _RAIter,
+              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+    friend
+    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+    move(_RAIter __f,
+         _RAIter __l,
+         __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
+         typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*);
+
+    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+              class _OutputIterator>
+    friend
+    _OutputIterator
+    move(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+         __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+         _OutputIterator __r);
+
+    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+    friend
+    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+    move(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+         __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+         __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
+
+    template <class _RAIter,
+              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+    friend
+    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+    move_backward(_RAIter __f,
+                  _RAIter __l,
+                  __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
+                  typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*);
+
+    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+              class _OutputIterator>
+    friend
+    _OutputIterator
+    move_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+                  __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+                  _OutputIterator __r);
+
+    template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+              class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+    friend
+    __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+    move_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+                  __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+                  __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r);
+};
+
+template <class _ValueType, class _Pointer, class _Reference, class _MapPointer,
+          class _DiffType, _DiffType _BlockSize>
+const _DiffType __deque_iterator<_ValueType, _Pointer, _Reference, _MapPointer,
+                                 _DiffType, _BlockSize>::__block_size =
+    __deque_block_size<_ValueType, _DiffType>::value;
+
+// copy
+
+template <class _RAIter,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+copy(_RAIter __f,
+     _RAIter __l,
+     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
+     typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*)
+{
+    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::difference_type difference_type;
+    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::pointer pointer;
+    const difference_type __block_size = __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::__block_size;
+    while (__f != __l)
+    {
+        pointer __rb = __r.__ptr_;
+        pointer __re = *__r.__m_iter_ + __block_size;
+        difference_type __bs = __re - __rb;
+        difference_type __n = __l - __f;
+        _RAIter __m = __l;
+        if (__n > __bs)
+        {
+            __n = __bs;
+            __m = __f + __n;
+        }
+        _VSTD::copy(__f, __m, __rb);
+        __f = __m;
+        __r += __n;
+    }
+    return __r;
+}
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _OutputIterator>
+_OutputIterator
+copy(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+     _OutputIterator __r)
+{
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
+    const difference_type __block_size = __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::__block_size;
+    difference_type __n = __l - __f;
+    while (__n > 0)
+    {
+        pointer __fb = __f.__ptr_;
+        pointer __fe = *__f.__m_iter_ + __block_size;
+        difference_type __bs = __fe - __fb;
+        if (__bs > __n)
+        {
+            __bs = __n;
+            __fe = __fb + __bs;
+        }
+        __r = _VSTD::copy(__fb, __fe, __r);
+        __n -= __bs;
+        __f += __bs;
+    }
+    return __r;
+}
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+copy(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r)
+{
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
+    const difference_type __block_size = __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::__block_size;
+    difference_type __n = __l - __f;
+    while (__n > 0)
+    {
+        pointer __fb = __f.__ptr_;
+        pointer __fe = *__f.__m_iter_ + __block_size;
+        difference_type __bs = __fe - __fb;
+        if (__bs > __n)
+        {
+            __bs = __n;
+            __fe = __fb + __bs;
+        }
+        __r = _VSTD::copy(__fb, __fe, __r);
+        __n -= __bs;
+        __f += __bs;
+    }
+    return __r;
+}
+
+// copy_backward
+
+template <class _RAIter,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+copy_backward(_RAIter __f,
+              _RAIter __l,
+              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
+              typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*)
+{
+    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::difference_type difference_type;
+    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::pointer pointer;
+    while (__f != __l)
+    {
+        __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __rp = _VSTD::prev(__r);
+        pointer __rb = *__rp.__m_iter_;
+        pointer __re = __rp.__ptr_ + 1;
+        difference_type __bs = __re - __rb;
+        difference_type __n = __l - __f;
+        _RAIter __m = __f;
+        if (__n > __bs)
+        {
+            __n = __bs;
+            __m = __l - __n;
+        }
+        _VSTD::copy_backward(__m, __l, __re);
+        __l = __m;
+        __r -= __n;
+    }
+    return __r;
+}
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _OutputIterator>
+_OutputIterator
+copy_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+              _OutputIterator __r)
+{
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
+    difference_type __n = __l - __f;
+    while (__n > 0)
+    {
+        --__l;
+        pointer __lb = *__l.__m_iter_;
+        pointer __le = __l.__ptr_ + 1;
+        difference_type __bs = __le - __lb;
+        if (__bs > __n)
+        {
+            __bs = __n;
+            __lb = __le - __bs;
+        }
+        __r = _VSTD::copy_backward(__lb, __le, __r);
+        __n -= __bs;
+        __l -= __bs - 1;
+    }
+    return __r;
+}
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+copy_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r)
+{
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
+    difference_type __n = __l - __f;
+    while (__n > 0)
+    {
+        --__l;
+        pointer __lb = *__l.__m_iter_;
+        pointer __le = __l.__ptr_ + 1;
+        difference_type __bs = __le - __lb;
+        if (__bs > __n)
+        {
+            __bs = __n;
+            __lb = __le - __bs;
+        }
+        __r = _VSTD::copy_backward(__lb, __le, __r);
+        __n -= __bs;
+        __l -= __bs - 1;
+    }
+    return __r;
+}
+
+// move
+
+template <class _RAIter,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+move(_RAIter __f,
+     _RAIter __l,
+     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
+     typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*)
+{
+    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::difference_type difference_type;
+    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::pointer pointer;
+    const difference_type __block_size = __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::__block_size;
+    while (__f != __l)
+    {
+        pointer __rb = __r.__ptr_;
+        pointer __re = *__r.__m_iter_ + __block_size;
+        difference_type __bs = __re - __rb;
+        difference_type __n = __l - __f;
+        _RAIter __m = __l;
+        if (__n > __bs)
+        {
+            __n = __bs;
+            __m = __f + __n;
+        }
+        _VSTD::move(__f, __m, __rb);
+        __f = __m;
+        __r += __n;
+    }
+    return __r;
+}
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _OutputIterator>
+_OutputIterator
+move(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+     _OutputIterator __r)
+{
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
+    const difference_type __block_size = __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::__block_size;
+    difference_type __n = __l - __f;
+    while (__n > 0)
+    {
+        pointer __fb = __f.__ptr_;
+        pointer __fe = *__f.__m_iter_ + __block_size;
+        difference_type __bs = __fe - __fb;
+        if (__bs > __n)
+        {
+            __bs = __n;
+            __fe = __fb + __bs;
+        }
+        __r = _VSTD::move(__fb, __fe, __r);
+        __n -= __bs;
+        __f += __bs;
+    }
+    return __r;
+}
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+move(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+     __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+     __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r)
+{
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
+    const difference_type __block_size = __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::__block_size;
+    difference_type __n = __l - __f;
+    while (__n > 0)
+    {
+        pointer __fb = __f.__ptr_;
+        pointer __fe = *__f.__m_iter_ + __block_size;
+        difference_type __bs = __fe - __fb;
+        if (__bs > __n)
+        {
+            __bs = __n;
+            __fe = __fb + __bs;
+        }
+        __r = _VSTD::move(__fb, __fe, __r);
+        __n -= __bs;
+        __f += __bs;
+    }
+    return __r;
+}
+
+// move_backward
+
+template <class _RAIter,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+move_backward(_RAIter __f,
+              _RAIter __l,
+              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r,
+              typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*)
+{
+    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::difference_type difference_type;
+    typedef typename __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>::pointer pointer;
+    while (__f != __l)
+    {
+        __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __rp = _VSTD::prev(__r);
+        pointer __rb = *__rp.__m_iter_;
+        pointer __re = __rp.__ptr_ + 1;
+        difference_type __bs = __re - __rb;
+        difference_type __n = __l - __f;
+        _RAIter __m = __f;
+        if (__n > __bs)
+        {
+            __n = __bs;
+            __m = __l - __n;
+        }
+        _VSTD::move_backward(__m, __l, __re);
+        __l = __m;
+        __r -= __n;
+    }
+    return __r;
+}
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _OutputIterator>
+_OutputIterator
+move_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+              _OutputIterator __r)
+{
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
+    difference_type __n = __l - __f;
+    while (__n > 0)
+    {
+        --__l;
+        pointer __lb = *__l.__m_iter_;
+        pointer __le = __l.__ptr_ + 1;
+        difference_type __bs = __le - __lb;
+        if (__bs > __n)
+        {
+            __bs = __n;
+            __lb = __le - __bs;
+        }
+        __r = _VSTD::move_backward(__lb, __le, __r);
+        __n -= __bs;
+        __l -= __bs - 1;
+    }
+    return __r;
+}
+
+template <class _V1, class _P1, class _R1, class _M1, class _D1, _D1 _B1,
+          class _V2, class _P2, class _R2, class _M2, class _D2, _D2 _B2>
+__deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2>
+move_backward(__deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __f,
+              __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1> __l,
+              __deque_iterator<_V2, _P2, _R2, _M2, _D2, _B2> __r)
+{
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::difference_type difference_type;
+    typedef typename __deque_iterator<_V1, _P1, _R1, _M1, _D1, _B1>::pointer pointer;
+    difference_type __n = __l - __f;
+    while (__n > 0)
+    {
+        --__l;
+        pointer __lb = *__l.__m_iter_;
+        pointer __le = __l.__ptr_ + 1;
+        difference_type __bs = __le - __lb;
+        if (__bs > __n)
+        {
+            __bs = __n;
+            __lb = __le - __bs;
+        }
+        __r = _VSTD::move_backward(__lb, __le, __r);
+        __n -= __bs;
+        __l -= __bs - 1;
+    }
+    return __r;
+}
+
+template <class _Tp, class _Allocator>
+class __deque_base
+{
+    __deque_base(const __deque_base& __c);
+    __deque_base& operator=(const __deque_base& __c);
+public:
+    typedef _Allocator                               allocator_type;
+    typedef allocator_traits<allocator_type>         __alloc_traits;
+    typedef typename __alloc_traits::size_type       size_type;
+
+    typedef _Tp                                      value_type;
+    typedef value_type&                              reference;
+    typedef const value_type&                        const_reference;
+    typedef typename __alloc_traits::difference_type difference_type;
+    typedef typename __alloc_traits::pointer         pointer;
+    typedef typename __alloc_traits::const_pointer   const_pointer;
+
+    static const difference_type __block_size;
+
+    typedef typename __rebind_alloc_helper<__alloc_traits, pointer>::type __pointer_allocator;
+    typedef allocator_traits<__pointer_allocator>        __map_traits;
+    typedef typename __map_traits::pointer               __map_pointer;
+    typedef typename __rebind_alloc_helper<__alloc_traits, const_pointer>::type __const_pointer_allocator;
+    typedef typename allocator_traits<__const_pointer_allocator>::const_pointer __map_const_pointer;
+    typedef __split_buffer<pointer, __pointer_allocator> __map;
+
+    typedef __deque_iterator<value_type, pointer, reference, __map_pointer,
+                             difference_type>    iterator;
+    typedef __deque_iterator<value_type, const_pointer, const_reference, __map_const_pointer,
+                             difference_type>    const_iterator;
+
+    struct __deque_block_range {
+      explicit __deque_block_range(pointer __b, pointer __e) _NOEXCEPT : __begin_(__b), __end_(__e) {}
+      const pointer __begin_;
+      const pointer __end_;
+    };
+
+    struct __deque_range {
+      iterator __pos_;
+      const iterator __end_;
+
+      __deque_range(iterator __pos, iterator __e) _NOEXCEPT
+        : __pos_(__pos), __end_(__e) {}
+
+      explicit operator bool() const _NOEXCEPT {
+        return __pos_ != __end_;
+      }
+
+      __deque_range begin() const {
+        return *this;
+      }
+
+      __deque_range end() const {
+        return __deque_range(__end_, __end_);
+      }
+      __deque_block_range operator*() const _NOEXCEPT {
+         if (__pos_.__m_iter_ == __end_.__m_iter_) {
+          return __deque_block_range(__pos_.__ptr_, __end_.__ptr_);
+        }
+        return __deque_block_range(__pos_.__ptr_, *__pos_.__m_iter_ + __block_size);
+      }
+
+      __deque_range& operator++() _NOEXCEPT {
+        if (__pos_.__m_iter_ == __end_.__m_iter_) {
+          __pos_ = __end_;
+        } else {
+          ++__pos_.__m_iter_;
+          __pos_.__ptr_ = *__pos_.__m_iter_;
+        }
+        return *this;
+      }
+
+
+      friend bool operator==(__deque_range const& __lhs, __deque_range const& __rhs) {
+        return __lhs.__pos_ == __rhs.__pos_;
+      }
+      friend bool operator!=(__deque_range const& __lhs, __deque_range const& __rhs) {
+        return !(__lhs == __rhs);
+      }
+    };
+
+
+
+    struct _ConstructTransaction {
+      _ConstructTransaction(__deque_base* __db, __deque_block_range& __r)
+        : __pos_(__r.__begin_), __end_(__r.__end_), __begin_(__r.__begin_), __base_(__db) {}
+
+
+      ~_ConstructTransaction() {
+        __base_->size() += (__pos_ - __begin_);
+      }
+
+      pointer __pos_;
+      const pointer __end_;
+    private:
+      const pointer __begin_;
+      __deque_base * const __base_;
+    };
+
+protected:
+    __map __map_;
+    size_type __start_;
+    __compressed_pair<size_type, allocator_type> __size_;
+
+    iterator       begin() _NOEXCEPT;
+    const_iterator begin() const _NOEXCEPT;
+    iterator       end() _NOEXCEPT;
+    const_iterator end() const _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY size_type&            size()          {return __size_.first();}
+    _LIBCPP_INLINE_VISIBILITY
+    const size_type& size() const _NOEXCEPT {return __size_.first();}
+    _LIBCPP_INLINE_VISIBILITY allocator_type&       __alloc()       {return __size_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    const allocator_type& __alloc() const _NOEXCEPT {return __size_.second();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __deque_base()
+        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __deque_base(const allocator_type& __a);
+public:
+    ~__deque_base();
+
+#ifndef _LIBCPP_CXX03_LANG
+    __deque_base(__deque_base&& __c)
+        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value);
+    __deque_base(__deque_base&& __c, const allocator_type& __a);
+#endif // _LIBCPP_CXX03_LANG
+
+    void swap(__deque_base& __c)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT;
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<allocator_type>::value);
+#endif
+protected:
+    void clear() _NOEXCEPT;
+
+    bool __invariants() const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign(__deque_base& __c)
+        _NOEXCEPT_(__alloc_traits::propagate_on_container_move_assignment::value &&
+                   is_nothrow_move_assignable<allocator_type>::value)
+    {
+        __map_ = _VSTD::move(__c.__map_);
+        __start_ = __c.__start_;
+        size() = __c.size();
+        __move_assign_alloc(__c);
+        __c.__start_ = __c.size() = 0;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__deque_base& __c)
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_move_assignment::value ||
+                   is_nothrow_move_assignable<allocator_type>::value)
+        {__move_assign_alloc(__c, integral_constant<bool,
+                      __alloc_traits::propagate_on_container_move_assignment::value>());}
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__deque_base& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
+        {
+            __alloc() = _VSTD::move(__c.__alloc());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__deque_base&, false_type) _NOEXCEPT
+        {}
+};
+
+template <class _Tp, class _Allocator>
+const typename __deque_base<_Tp, _Allocator>::difference_type
+    __deque_base<_Tp, _Allocator>::__block_size =
+        __deque_block_size<value_type, difference_type>::value;
+
+template <class _Tp, class _Allocator>
+bool
+__deque_base<_Tp, _Allocator>::__invariants() const
+{
+    if (!__map_.__invariants())
+        return false;
+    if (__map_.size() >= size_type(-1) / __block_size)
+        return false;
+    for (typename __map::const_iterator __i = __map_.begin(), __e = __map_.end();
+         __i != __e; ++__i)
+        if (*__i == nullptr)
+            return false;
+    if (__map_.size() != 0)
+    {
+        if (size() >= __map_.size() * __block_size)
+            return false;
+        if (__start_ >= __map_.size() * __block_size - size())
+            return false;
+    }
+    else
+    {
+        if (size() != 0)
+            return false;
+        if (__start_ != 0)
+            return false;
+    }
+    return true;
+}
+
+template <class _Tp, class _Allocator>
+typename __deque_base<_Tp, _Allocator>::iterator
+__deque_base<_Tp, _Allocator>::begin() _NOEXCEPT
+{
+    __map_pointer __mp = __map_.begin() + __start_ / __block_size;
+    return iterator(__mp, __map_.empty() ? 0 : *__mp + __start_ % __block_size);
+}
+
+template <class _Tp, class _Allocator>
+typename __deque_base<_Tp, _Allocator>::const_iterator
+__deque_base<_Tp, _Allocator>::begin() const _NOEXCEPT
+{
+    __map_const_pointer __mp = static_cast<__map_const_pointer>(__map_.begin() + __start_ / __block_size);
+    return const_iterator(__mp, __map_.empty() ? 0 : *__mp + __start_ % __block_size);
+}
+
+template <class _Tp, class _Allocator>
+typename __deque_base<_Tp, _Allocator>::iterator
+__deque_base<_Tp, _Allocator>::end() _NOEXCEPT
+{
+    size_type __p = size() + __start_;
+    __map_pointer __mp = __map_.begin() + __p / __block_size;
+    return iterator(__mp, __map_.empty() ? 0 : *__mp + __p % __block_size);
+}
+
+template <class _Tp, class _Allocator>
+typename __deque_base<_Tp, _Allocator>::const_iterator
+__deque_base<_Tp, _Allocator>::end() const _NOEXCEPT
+{
+    size_type __p = size() + __start_;
+    __map_const_pointer __mp = static_cast<__map_const_pointer>(__map_.begin() + __p / __block_size);
+    return const_iterator(__mp, __map_.empty() ? 0 : *__mp + __p % __block_size);
+}
+
+template <class _Tp, class _Allocator>
+inline
+__deque_base<_Tp, _Allocator>::__deque_base()
+    _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
+    : __start_(0), __size_(0, __default_init_tag()) {}
+
+template <class _Tp, class _Allocator>
+inline
+__deque_base<_Tp, _Allocator>::__deque_base(const allocator_type& __a)
+    : __map_(__pointer_allocator(__a)), __start_(0), __size_(0, __a) {}
+
+template <class _Tp, class _Allocator>
+__deque_base<_Tp, _Allocator>::~__deque_base()
+{
+    clear();
+    typename __map::iterator __i = __map_.begin();
+    typename __map::iterator __e = __map_.end();
+    for (; __i != __e; ++__i)
+        __alloc_traits::deallocate(__alloc(), *__i, __block_size);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Allocator>
+__deque_base<_Tp, _Allocator>::__deque_base(__deque_base&& __c)
+    _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
+    : __map_(_VSTD::move(__c.__map_)),
+      __start_(_VSTD::move(__c.__start_)),
+      __size_(_VSTD::move(__c.__size_))
+{
+    __c.__start_ = 0;
+    __c.size() = 0;
+}
+
+template <class _Tp, class _Allocator>
+__deque_base<_Tp, _Allocator>::__deque_base(__deque_base&& __c, const allocator_type& __a)
+    : __map_(_VSTD::move(__c.__map_), __pointer_allocator(__a)),
+      __start_(_VSTD::move(__c.__start_)),
+      __size_(_VSTD::move(__c.size()), __a)
+{
+    if (__a == __c.__alloc())
+    {
+        __c.__start_ = 0;
+        __c.size() = 0;
+    }
+    else
+    {
+        __map_.clear();
+        __start_ = 0;
+        size() = 0;
+    }
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Allocator>
+void
+__deque_base<_Tp, _Allocator>::swap(__deque_base& __c)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<allocator_type>::value)
+#endif
+{
+    __map_.swap(__c.__map_);
+    _VSTD::swap(__start_, __c.__start_);
+    _VSTD::swap(size(), __c.size());
+    _VSTD::__swap_allocator(__alloc(), __c.__alloc());
+}
+
+template <class _Tp, class _Allocator>
+void
+__deque_base<_Tp, _Allocator>::clear() _NOEXCEPT
+{
+    allocator_type& __a = __alloc();
+    for (iterator __i = begin(), __e = end(); __i != __e; ++__i)
+        __alloc_traits::destroy(__a, _VSTD::addressof(*__i));
+    size() = 0;
+    while (__map_.size() > 2)
+    {
+        __alloc_traits::deallocate(__a, __map_.front(), __block_size);
+        __map_.pop_front();
+    }
+    switch (__map_.size())
+    {
+    case 1:
+        __start_ = __block_size / 2;
+        break;
+    case 2:
+        __start_ = __block_size;
+        break;
+    }
+}
+
+template <class _Tp, class _Allocator /*= allocator<_Tp>*/>
+class _LIBCPP_TEMPLATE_VIS deque
+    : private __deque_base<_Tp, _Allocator>
+{
+public:
+    // types:
+
+    typedef _Tp value_type;
+    typedef _Allocator allocator_type;
+
+    static_assert((is_same<typename allocator_type::value_type, value_type>::value),
+                  "Allocator::value_type must be same type as value_type");
+
+    typedef __deque_base<value_type, allocator_type> __base;
+
+    typedef typename __base::__alloc_traits        __alloc_traits;
+    typedef typename __base::reference             reference;
+    typedef typename __base::const_reference       const_reference;
+    typedef typename __base::iterator              iterator;
+    typedef typename __base::const_iterator        const_iterator;
+    typedef typename __base::size_type             size_type;
+    typedef typename __base::difference_type       difference_type;
+
+    typedef typename __base::pointer               pointer;
+    typedef typename __base::const_pointer         const_pointer;
+    typedef _VSTD::reverse_iterator<iterator>       reverse_iterator;
+    typedef _VSTD::reverse_iterator<const_iterator> const_reverse_iterator;
+
+    using typename __base::__deque_range;
+    using typename __base::__deque_block_range;
+    using typename __base::_ConstructTransaction;
+
+    // construct/copy/destroy:
+    _LIBCPP_INLINE_VISIBILITY
+    deque()
+        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
+        {}
+    _LIBCPP_INLINE_VISIBILITY explicit deque(const allocator_type& __a) : __base(__a) {}
+    explicit deque(size_type __n);
+#if _LIBCPP_STD_VER > 11
+    explicit deque(size_type __n, const _Allocator& __a);
+#endif
+    deque(size_type __n, const value_type& __v);
+    deque(size_type __n, const value_type& __v, const allocator_type& __a);
+    template <class _InputIter>
+        deque(_InputIter __f, _InputIter __l,
+              typename enable_if<__is_cpp17_input_iterator<_InputIter>::value>::type* = 0);
+    template <class _InputIter>
+        deque(_InputIter __f, _InputIter __l, const allocator_type& __a,
+              typename enable_if<__is_cpp17_input_iterator<_InputIter>::value>::type* = 0);
+    deque(const deque& __c);
+    deque(const deque& __c, const __identity_t<allocator_type>& __a);
+
+    deque& operator=(const deque& __c);
+
+#ifndef _LIBCPP_CXX03_LANG
+    deque(initializer_list<value_type> __il);
+    deque(initializer_list<value_type> __il, const allocator_type& __a);
+
+    _LIBCPP_INLINE_VISIBILITY
+    deque& operator=(initializer_list<value_type> __il) {assign(__il); return *this;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    deque(deque&& __c) _NOEXCEPT_(is_nothrow_move_constructible<__base>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    deque(deque&& __c, const __identity_t<allocator_type>& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    deque& operator=(deque&& __c)
+        _NOEXCEPT_(__alloc_traits::propagate_on_container_move_assignment::value &&
+                   is_nothrow_move_assignable<allocator_type>::value);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void assign(initializer_list<value_type> __il) {assign(__il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+
+    template <class _InputIter>
+        void assign(_InputIter __f, _InputIter __l,
+                    typename enable_if<__is_cpp17_input_iterator<_InputIter>::value &&
+                                      !__is_cpp17_random_access_iterator<_InputIter>::value>::type* = 0);
+    template <class _RAIter>
+        void assign(_RAIter __f, _RAIter __l,
+                    typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type* = 0);
+    void assign(size_type __n, const value_type& __v);
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT;
+
+    // iterators:
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       begin() _NOEXCEPT       {return __base::begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const _NOEXCEPT {return __base::begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       end() _NOEXCEPT         {return __base::end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()   const _NOEXCEPT {return __base::end();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reverse_iterator       rbegin() _NOEXCEPT
+        {return       reverse_iterator(__base::end());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rbegin() const _NOEXCEPT
+        {return const_reverse_iterator(__base::end());}
+    _LIBCPP_INLINE_VISIBILITY
+    reverse_iterator       rend() _NOEXCEPT
+        {return       reverse_iterator(__base::begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rend()   const _NOEXCEPT
+        {return const_reverse_iterator(__base::begin());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator         cbegin()  const _NOEXCEPT
+        {return __base::begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator         cend()    const _NOEXCEPT
+        {return __base::end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crbegin() const _NOEXCEPT
+        {return const_reverse_iterator(__base::end());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crend()   const _NOEXCEPT
+        {return const_reverse_iterator(__base::begin());}
+
+    // capacity:
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT {return __base::size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT
+        {return _VSTD::min<size_type>(
+            __alloc_traits::max_size(__base::__alloc()),
+            numeric_limits<difference_type>::max());}
+    void resize(size_type __n);
+    void resize(size_type __n, const value_type& __v);
+    void shrink_to_fit() _NOEXCEPT;
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT {return __base::size() == 0;}
+
+    // element access:
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator[](size_type __i) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference operator[](size_type __i) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    reference at(size_type __i);
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference at(size_type __i) const;
+    _LIBCPP_INLINE_VISIBILITY
+    reference front() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference front() const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    reference back() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference back() const _NOEXCEPT;
+
+    // 23.2.2.3 modifiers:
+    void push_front(const value_type& __v);
+    void push_back(const value_type& __v);
+#ifndef _LIBCPP_CXX03_LANG
+#if _LIBCPP_STD_VER > 14
+    template <class... _Args> reference emplace_front(_Args&&... __args);
+    template <class... _Args> reference emplace_back (_Args&&... __args);
+#else
+    template <class... _Args> void      emplace_front(_Args&&... __args);
+    template <class... _Args> void      emplace_back (_Args&&... __args);
+#endif
+    template <class... _Args> iterator emplace(const_iterator __p, _Args&&... __args);
+
+    void push_front(value_type&& __v);
+    void push_back(value_type&& __v);
+    iterator insert(const_iterator __p, value_type&& __v);
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, initializer_list<value_type> __il)
+        {return insert(__p, __il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+    iterator insert(const_iterator __p, const value_type& __v);
+    iterator insert(const_iterator __p, size_type __n, const value_type& __v);
+    template <class _InputIter>
+        iterator insert(const_iterator __p, _InputIter __f, _InputIter __l,
+                         typename enable_if<__is_cpp17_input_iterator<_InputIter>::value
+                                         &&!__is_cpp17_forward_iterator<_InputIter>::value>::type* = 0);
+    template <class _ForwardIterator>
+        iterator insert(const_iterator __p, _ForwardIterator __f, _ForwardIterator __l,
+                               typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value
+                                         &&!__is_cpp17_bidirectional_iterator<_ForwardIterator>::value>::type* = 0);
+    template <class _BiIter>
+        iterator insert(const_iterator __p, _BiIter __f, _BiIter __l,
+                         typename enable_if<__is_cpp17_bidirectional_iterator<_BiIter>::value>::type* = 0);
+
+    void pop_front();
+    void pop_back();
+    iterator erase(const_iterator __p);
+    iterator erase(const_iterator __f, const_iterator __l);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(deque& __c)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT;
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                   __is_nothrow_swappable<allocator_type>::value);
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool __invariants() const {return __base::__invariants();}
+
+    typedef typename __base::__map_const_pointer __map_const_pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    static size_type __recommend_blocks(size_type __n)
+    {
+        return __n / __base::__block_size + (__n % __base::__block_size != 0);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    size_type __capacity() const
+    {
+        return __base::__map_.size() == 0 ? 0 : __base::__map_.size() * __base::__block_size - 1;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    size_type __block_count() const
+    {
+        return __base::__map_.size();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type __front_spare() const
+    {
+        return __base::__start_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    size_type __front_spare_blocks() const {
+      return __front_spare() / __base::__block_size;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    size_type __back_spare() const
+    {
+        return __capacity() - (__base::__start_ + __base::size());
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    size_type __back_spare_blocks() const {
+      return __back_spare() / __base::__block_size;
+    }
+
+ private:
+    _LIBCPP_INLINE_VISIBILITY
+    bool __maybe_remove_front_spare(bool __keep_one = true) {
+      if (__front_spare_blocks() >= 2 || (!__keep_one && __front_spare_blocks())) {
+        __alloc_traits::deallocate(__base::__alloc(), __base::__map_.front(),
+                                   __base::__block_size);
+        __base::__map_.pop_front();
+        __base::__start_ -= __base::__block_size;
+        return true;
+      }
+      return false;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool __maybe_remove_back_spare(bool __keep_one = true) {
+      if (__back_spare_blocks() >= 2 || (!__keep_one && __back_spare_blocks())) {
+        __alloc_traits::deallocate(__base::__alloc(), __base::__map_.back(),
+                                   __base::__block_size);
+        __base::__map_.pop_back();
+        return true;
+      }
+      return false;
+    }
+
+    template <class _InpIter>
+        void __append(_InpIter __f, _InpIter __l,
+                 typename enable_if<__is_cpp17_input_iterator<_InpIter>::value &&
+                                   !__is_cpp17_forward_iterator<_InpIter>::value>::type* = 0);
+    template <class _ForIter>
+        void __append(_ForIter __f, _ForIter __l,
+                      typename enable_if<__is_cpp17_forward_iterator<_ForIter>::value>::type* = 0);
+    void __append(size_type __n);
+    void __append(size_type __n, const value_type& __v);
+    void __erase_to_end(const_iterator __f);
+    void __add_front_capacity();
+    void __add_front_capacity(size_type __n);
+    void __add_back_capacity();
+    void __add_back_capacity(size_type __n);
+    iterator __move_and_check(iterator __f, iterator __l, iterator __r,
+                              const_pointer& __vt);
+    iterator __move_backward_and_check(iterator __f, iterator __l, iterator __r,
+                                       const_pointer& __vt);
+    void __move_construct_and_check(iterator __f, iterator __l,
+                                    iterator __r, const_pointer& __vt);
+    void __move_construct_backward_and_check(iterator __f, iterator __l,
+                                             iterator __r, const_pointer& __vt);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const deque& __c)
+        {__copy_assign_alloc(__c, integral_constant<bool,
+                      __alloc_traits::propagate_on_container_copy_assignment::value>());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const deque& __c, true_type)
+        {
+            if (__base::__alloc() != __c.__alloc())
+            {
+                clear();
+                shrink_to_fit();
+            }
+            __base::__alloc() = __c.__alloc();
+            __base::__map_.__alloc() = __c.__map_.__alloc();
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const deque&, false_type)
+        {}
+
+    void __move_assign(deque& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value);
+    void __move_assign(deque& __c, false_type);
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator,
+         class _Alloc = allocator<__iter_value_type<_InputIterator>>,
+         class = enable_if_t<__is_allocator<_Alloc>::value>
+         >
+deque(_InputIterator, _InputIterator)
+  -> deque<__iter_value_type<_InputIterator>, _Alloc>;
+
+template<class _InputIterator,
+         class _Alloc,
+         class = enable_if_t<__is_allocator<_Alloc>::value>
+         >
+deque(_InputIterator, _InputIterator, _Alloc)
+  -> deque<__iter_value_type<_InputIterator>, _Alloc>;
+#endif
+
+
+template <class _Tp, class _Allocator>
+deque<_Tp, _Allocator>::deque(size_type __n)
+{
+    if (__n > 0)
+        __append(__n);
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp, class _Allocator>
+deque<_Tp, _Allocator>::deque(size_type __n, const _Allocator& __a)
+    : __base(__a)
+{
+    if (__n > 0)
+        __append(__n);
+}
+#endif
+
+template <class _Tp, class _Allocator>
+deque<_Tp, _Allocator>::deque(size_type __n, const value_type& __v)
+{
+    if (__n > 0)
+        __append(__n, __v);
+}
+
+template <class _Tp, class _Allocator>
+deque<_Tp, _Allocator>::deque(size_type __n, const value_type& __v, const allocator_type& __a)
+    : __base(__a)
+{
+    if (__n > 0)
+        __append(__n, __v);
+}
+
+template <class _Tp, class _Allocator>
+template <class _InputIter>
+deque<_Tp, _Allocator>::deque(_InputIter __f, _InputIter __l,
+              typename enable_if<__is_cpp17_input_iterator<_InputIter>::value>::type*)
+{
+    __append(__f, __l);
+}
+
+template <class _Tp, class _Allocator>
+template <class _InputIter>
+deque<_Tp, _Allocator>::deque(_InputIter __f, _InputIter __l, const allocator_type& __a,
+              typename enable_if<__is_cpp17_input_iterator<_InputIter>::value>::type*)
+    : __base(__a)
+{
+    __append(__f, __l);
+}
+
+template <class _Tp, class _Allocator>
+deque<_Tp, _Allocator>::deque(const deque& __c)
+    : __base(__alloc_traits::select_on_container_copy_construction(__c.__alloc()))
+{
+    __append(__c.begin(), __c.end());
+}
+
+template <class _Tp, class _Allocator>
+deque<_Tp, _Allocator>::deque(const deque& __c, const __identity_t<allocator_type>& __a)
+    : __base(__a)
+{
+    __append(__c.begin(), __c.end());
+}
+
+template <class _Tp, class _Allocator>
+deque<_Tp, _Allocator>&
+deque<_Tp, _Allocator>::operator=(const deque& __c)
+{
+    if (this != _VSTD::addressof(__c))
+    {
+        __copy_assign_alloc(__c);
+        assign(__c.begin(), __c.end());
+    }
+    return *this;
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Allocator>
+deque<_Tp, _Allocator>::deque(initializer_list<value_type> __il)
+{
+    __append(__il.begin(), __il.end());
+}
+
+template <class _Tp, class _Allocator>
+deque<_Tp, _Allocator>::deque(initializer_list<value_type> __il, const allocator_type& __a)
+    : __base(__a)
+{
+    __append(__il.begin(), __il.end());
+}
+
+template <class _Tp, class _Allocator>
+inline
+deque<_Tp, _Allocator>::deque(deque&& __c)
+    _NOEXCEPT_(is_nothrow_move_constructible<__base>::value)
+    : __base(_VSTD::move(__c))
+{
+}
+
+template <class _Tp, class _Allocator>
+inline
+deque<_Tp, _Allocator>::deque(deque&& __c, const __identity_t<allocator_type>& __a)
+    : __base(_VSTD::move(__c), __a)
+{
+    if (__a != __c.__alloc())
+    {
+        typedef move_iterator<iterator> _Ip;
+        assign(_Ip(__c.begin()), _Ip(__c.end()));
+    }
+}
+
+template <class _Tp, class _Allocator>
+inline
+deque<_Tp, _Allocator>&
+deque<_Tp, _Allocator>::operator=(deque&& __c)
+        _NOEXCEPT_(__alloc_traits::propagate_on_container_move_assignment::value &&
+                   is_nothrow_move_assignable<allocator_type>::value)
+{
+    __move_assign(__c, integral_constant<bool,
+          __alloc_traits::propagate_on_container_move_assignment::value>());
+    return *this;
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::__move_assign(deque& __c, false_type)
+{
+    if (__base::__alloc() != __c.__alloc())
+    {
+        typedef move_iterator<iterator> _Ip;
+        assign(_Ip(__c.begin()), _Ip(__c.end()));
+    }
+    else
+        __move_assign(__c, true_type());
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::__move_assign(deque& __c, true_type)
+    _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
+{
+    clear();
+    shrink_to_fit();
+    __base::__move_assign(__c);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Allocator>
+template <class _InputIter>
+void
+deque<_Tp, _Allocator>::assign(_InputIter __f, _InputIter __l,
+                               typename enable_if<__is_cpp17_input_iterator<_InputIter>::value &&
+                                                 !__is_cpp17_random_access_iterator<_InputIter>::value>::type*)
+{
+    iterator __i = __base::begin();
+    iterator __e = __base::end();
+    for (; __f != __l && __i != __e; ++__f, (void) ++__i)
+        *__i = *__f;
+    if (__f != __l)
+        __append(__f, __l);
+    else
+        __erase_to_end(__i);
+}
+
+template <class _Tp, class _Allocator>
+template <class _RAIter>
+void
+deque<_Tp, _Allocator>::assign(_RAIter __f, _RAIter __l,
+                               typename enable_if<__is_cpp17_random_access_iterator<_RAIter>::value>::type*)
+{
+    if (static_cast<size_type>(__l - __f) > __base::size())
+    {
+        _RAIter __m = __f + __base::size();
+        _VSTD::copy(__f, __m, __base::begin());
+        __append(__m, __l);
+    }
+    else
+        __erase_to_end(_VSTD::copy(__f, __l, __base::begin()));
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::assign(size_type __n, const value_type& __v)
+{
+    if (__n > __base::size())
+    {
+        _VSTD::fill_n(__base::begin(), __base::size(), __v);
+        __n -= __base::size();
+        __append(__n, __v);
+    }
+    else
+        __erase_to_end(_VSTD::fill_n(__base::begin(), __n, __v));
+}
+
+template <class _Tp, class _Allocator>
+inline
+_Allocator
+deque<_Tp, _Allocator>::get_allocator() const _NOEXCEPT
+{
+    return __base::__alloc();
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::resize(size_type __n)
+{
+    if (__n > __base::size())
+        __append(__n - __base::size());
+    else if (__n < __base::size())
+        __erase_to_end(__base::begin() + __n);
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::resize(size_type __n, const value_type& __v)
+{
+    if (__n > __base::size())
+        __append(__n - __base::size(), __v);
+    else if (__n < __base::size())
+        __erase_to_end(__base::begin() + __n);
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::shrink_to_fit() _NOEXCEPT
+{
+    allocator_type& __a = __base::__alloc();
+    if (empty())
+    {
+        while (__base::__map_.size() > 0)
+        {
+            __alloc_traits::deallocate(__a, __base::__map_.back(), __base::__block_size);
+            __base::__map_.pop_back();
+        }
+        __base::__start_ = 0;
+    }
+    else
+    {
+      __maybe_remove_front_spare(/*__keep_one=*/false);
+      __maybe_remove_back_spare(/*__keep_one=*/false);
+    }
+    __base::__map_.shrink_to_fit();
+}
+
+template <class _Tp, class _Allocator>
+inline
+typename deque<_Tp, _Allocator>::reference
+deque<_Tp, _Allocator>::operator[](size_type __i) _NOEXCEPT
+{
+    size_type __p = __base::__start_ + __i;
+    return *(*(__base::__map_.begin() + __p / __base::__block_size) + __p % __base::__block_size);
+}
+
+template <class _Tp, class _Allocator>
+inline
+typename deque<_Tp, _Allocator>::const_reference
+deque<_Tp, _Allocator>::operator[](size_type __i) const _NOEXCEPT
+{
+    size_type __p = __base::__start_ + __i;
+    return *(*(__base::__map_.begin() + __p / __base::__block_size) + __p % __base::__block_size);
+}
+
+template <class _Tp, class _Allocator>
+inline
+typename deque<_Tp, _Allocator>::reference
+deque<_Tp, _Allocator>::at(size_type __i)
+{
+    if (__i >= __base::size())
+        _VSTD::__throw_out_of_range("deque");
+    size_type __p = __base::__start_ + __i;
+    return *(*(__base::__map_.begin() + __p / __base::__block_size) + __p % __base::__block_size);
+}
+
+template <class _Tp, class _Allocator>
+inline
+typename deque<_Tp, _Allocator>::const_reference
+deque<_Tp, _Allocator>::at(size_type __i) const
+{
+    if (__i >= __base::size())
+        _VSTD::__throw_out_of_range("deque");
+    size_type __p = __base::__start_ + __i;
+    return *(*(__base::__map_.begin() + __p / __base::__block_size) + __p % __base::__block_size);
+}
+
+template <class _Tp, class _Allocator>
+inline
+typename deque<_Tp, _Allocator>::reference
+deque<_Tp, _Allocator>::front() _NOEXCEPT
+{
+    return *(*(__base::__map_.begin() + __base::__start_ / __base::__block_size)
+                                      + __base::__start_ % __base::__block_size);
+}
+
+template <class _Tp, class _Allocator>
+inline
+typename deque<_Tp, _Allocator>::const_reference
+deque<_Tp, _Allocator>::front() const _NOEXCEPT
+{
+    return *(*(__base::__map_.begin() + __base::__start_ / __base::__block_size)
+                                      + __base::__start_ % __base::__block_size);
+}
+
+template <class _Tp, class _Allocator>
+inline
+typename deque<_Tp, _Allocator>::reference
+deque<_Tp, _Allocator>::back() _NOEXCEPT
+{
+    size_type __p = __base::size() + __base::__start_ - 1;
+    return *(*(__base::__map_.begin() + __p / __base::__block_size) + __p % __base::__block_size);
+}
+
+template <class _Tp, class _Allocator>
+inline
+typename deque<_Tp, _Allocator>::const_reference
+deque<_Tp, _Allocator>::back() const _NOEXCEPT
+{
+    size_type __p = __base::size() + __base::__start_ - 1;
+    return *(*(__base::__map_.begin() + __p / __base::__block_size) + __p % __base::__block_size);
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::push_back(const value_type& __v)
+{
+    allocator_type& __a = __base::__alloc();
+    if (__back_spare() == 0)
+        __add_back_capacity();
+    // __back_spare() >= 1
+    __alloc_traits::construct(__a, _VSTD::addressof(*__base::end()), __v);
+    ++__base::size();
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::push_front(const value_type& __v)
+{
+    allocator_type& __a = __base::__alloc();
+    if (__front_spare() == 0)
+        __add_front_capacity();
+    // __front_spare() >= 1
+    __alloc_traits::construct(__a, _VSTD::addressof(*--__base::begin()), __v);
+    --__base::__start_;
+    ++__base::size();
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::push_back(value_type&& __v)
+{
+    allocator_type& __a = __base::__alloc();
+    if (__back_spare() == 0)
+        __add_back_capacity();
+    // __back_spare() >= 1
+    __alloc_traits::construct(__a, _VSTD::addressof(*__base::end()), _VSTD::move(__v));
+    ++__base::size();
+}
+
+template <class _Tp, class _Allocator>
+template <class... _Args>
+#if _LIBCPP_STD_VER > 14
+typename deque<_Tp, _Allocator>::reference
+#else
+void
+#endif
+deque<_Tp, _Allocator>::emplace_back(_Args&&... __args)
+{
+    allocator_type& __a = __base::__alloc();
+    if (__back_spare() == 0)
+        __add_back_capacity();
+    // __back_spare() >= 1
+    __alloc_traits::construct(__a, _VSTD::addressof(*__base::end()),
+                              _VSTD::forward<_Args>(__args)...);
+    ++__base::size();
+#if _LIBCPP_STD_VER > 14
+    return *--__base::end();
+#endif
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::push_front(value_type&& __v)
+{
+    allocator_type& __a = __base::__alloc();
+    if (__front_spare() == 0)
+        __add_front_capacity();
+    // __front_spare() >= 1
+    __alloc_traits::construct(__a, _VSTD::addressof(*--__base::begin()), _VSTD::move(__v));
+    --__base::__start_;
+    ++__base::size();
+}
+
+
+template <class _Tp, class _Allocator>
+template <class... _Args>
+#if _LIBCPP_STD_VER > 14
+typename deque<_Tp, _Allocator>::reference
+#else
+void
+#endif
+deque<_Tp, _Allocator>::emplace_front(_Args&&... __args)
+{
+    allocator_type& __a = __base::__alloc();
+    if (__front_spare() == 0)
+        __add_front_capacity();
+    // __front_spare() >= 1
+    __alloc_traits::construct(__a, _VSTD::addressof(*--__base::begin()), _VSTD::forward<_Args>(__args)...);
+    --__base::__start_;
+    ++__base::size();
+#if _LIBCPP_STD_VER > 14
+    return *__base::begin();
+#endif
+}
+
+template <class _Tp, class _Allocator>
+typename deque<_Tp, _Allocator>::iterator
+deque<_Tp, _Allocator>::insert(const_iterator __p, value_type&& __v)
+{
+    size_type __pos = __p - __base::begin();
+    size_type __to_end = __base::size() - __pos;
+    allocator_type& __a = __base::__alloc();
+    if (__pos < __to_end)
+    {   // insert by shifting things backward
+        if (__front_spare() == 0)
+            __add_front_capacity();
+        // __front_spare() >= 1
+        if (__pos == 0)
+        {
+            __alloc_traits::construct(__a, _VSTD::addressof(*--__base::begin()), _VSTD::move(__v));
+            --__base::__start_;
+            ++__base::size();
+        }
+        else
+        {
+            iterator __b = __base::begin();
+            iterator __bm1 = _VSTD::prev(__b);
+            __alloc_traits::construct(__a, _VSTD::addressof(*__bm1), _VSTD::move(*__b));
+            --__base::__start_;
+            ++__base::size();
+            if (__pos > 1)
+                __b = _VSTD::move(_VSTD::next(__b), __b + __pos, __b);
+            *__b = _VSTD::move(__v);
+        }
+    }
+    else
+    {   // insert by shifting things forward
+        if (__back_spare() == 0)
+            __add_back_capacity();
+        // __back_capacity >= 1
+        size_type __de = __base::size() - __pos;
+        if (__de == 0)
+        {
+            __alloc_traits::construct(__a, _VSTD::addressof(*__base::end()), _VSTD::move(__v));
+            ++__base::size();
+        }
+        else
+        {
+            iterator __e = __base::end();
+            iterator __em1 = _VSTD::prev(__e);
+            __alloc_traits::construct(__a, _VSTD::addressof(*__e), _VSTD::move(*__em1));
+            ++__base::size();
+            if (__de > 1)
+                __e = _VSTD::move_backward(__e - __de, __em1, __e);
+            *--__e = _VSTD::move(__v);
+        }
+    }
+    return __base::begin() + __pos;
+}
+
+template <class _Tp, class _Allocator>
+template <class... _Args>
+typename deque<_Tp, _Allocator>::iterator
+deque<_Tp, _Allocator>::emplace(const_iterator __p, _Args&&... __args)
+{
+    size_type __pos = __p - __base::begin();
+    size_type __to_end = __base::size() - __pos;
+    allocator_type& __a = __base::__alloc();
+    if (__pos < __to_end)
+    {   // insert by shifting things backward
+        if (__front_spare() == 0)
+            __add_front_capacity();
+        // __front_spare() >= 1
+        if (__pos == 0)
+        {
+            __alloc_traits::construct(__a, _VSTD::addressof(*--__base::begin()), _VSTD::forward<_Args>(__args)...);
+            --__base::__start_;
+            ++__base::size();
+        }
+        else
+        {
+            __temp_value<value_type, _Allocator> __tmp(this->__alloc(), _VSTD::forward<_Args>(__args)...);
+            iterator __b = __base::begin();
+            iterator __bm1 = _VSTD::prev(__b);
+            __alloc_traits::construct(__a, _VSTD::addressof(*__bm1), _VSTD::move(*__b));
+            --__base::__start_;
+            ++__base::size();
+            if (__pos > 1)
+                __b = _VSTD::move(_VSTD::next(__b), __b + __pos, __b);
+            *__b = _VSTD::move(__tmp.get());
+        }
+    }
+    else
+    {   // insert by shifting things forward
+        if (__back_spare() == 0)
+            __add_back_capacity();
+        // __back_capacity >= 1
+        size_type __de = __base::size() - __pos;
+        if (__de == 0)
+        {
+            __alloc_traits::construct(__a, _VSTD::addressof(*__base::end()), _VSTD::forward<_Args>(__args)...);
+            ++__base::size();
+        }
+        else
+        {
+            __temp_value<value_type, _Allocator> __tmp(this->__alloc(), _VSTD::forward<_Args>(__args)...);
+            iterator __e = __base::end();
+            iterator __em1 = _VSTD::prev(__e);
+            __alloc_traits::construct(__a, _VSTD::addressof(*__e), _VSTD::move(*__em1));
+            ++__base::size();
+            if (__de > 1)
+                __e = _VSTD::move_backward(__e - __de, __em1, __e);
+            *--__e = _VSTD::move(__tmp.get());
+        }
+    }
+    return __base::begin() + __pos;
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+
+template <class _Tp, class _Allocator>
+typename deque<_Tp, _Allocator>::iterator
+deque<_Tp, _Allocator>::insert(const_iterator __p, const value_type& __v)
+{
+    size_type __pos = __p - __base::begin();
+    size_type __to_end = __base::size() - __pos;
+    allocator_type& __a = __base::__alloc();
+    if (__pos < __to_end)
+    {   // insert by shifting things backward
+        if (__front_spare() == 0)
+            __add_front_capacity();
+        // __front_spare() >= 1
+        if (__pos == 0)
+        {
+            __alloc_traits::construct(__a, _VSTD::addressof(*--__base::begin()), __v);
+            --__base::__start_;
+            ++__base::size();
+        }
+        else
+        {
+            const_pointer __vt = pointer_traits<const_pointer>::pointer_to(__v);
+            iterator __b = __base::begin();
+            iterator __bm1 = _VSTD::prev(__b);
+            if (__vt == pointer_traits<const_pointer>::pointer_to(*__b))
+                __vt = pointer_traits<const_pointer>::pointer_to(*__bm1);
+            __alloc_traits::construct(__a, _VSTD::addressof(*__bm1), _VSTD::move(*__b));
+            --__base::__start_;
+            ++__base::size();
+            if (__pos > 1)
+                __b = __move_and_check(_VSTD::next(__b), __b + __pos, __b, __vt);
+            *__b = *__vt;
+        }
+    }
+    else
+    {   // insert by shifting things forward
+        if (__back_spare() == 0)
+            __add_back_capacity();
+        // __back_capacity >= 1
+        size_type __de = __base::size() - __pos;
+        if (__de == 0)
+        {
+            __alloc_traits::construct(__a, _VSTD::addressof(*__base::end()), __v);
+            ++__base::size();
+        }
+        else
+        {
+            const_pointer __vt = pointer_traits<const_pointer>::pointer_to(__v);
+            iterator __e = __base::end();
+            iterator __em1 = _VSTD::prev(__e);
+            if (__vt == pointer_traits<const_pointer>::pointer_to(*__em1))
+                __vt = pointer_traits<const_pointer>::pointer_to(*__e);
+            __alloc_traits::construct(__a, _VSTD::addressof(*__e), _VSTD::move(*__em1));
+            ++__base::size();
+            if (__de > 1)
+                __e = __move_backward_and_check(__e - __de, __em1, __e, __vt);
+            *--__e = *__vt;
+        }
+    }
+    return __base::begin() + __pos;
+}
+
+template <class _Tp, class _Allocator>
+typename deque<_Tp, _Allocator>::iterator
+deque<_Tp, _Allocator>::insert(const_iterator __p, size_type __n, const value_type& __v)
+{
+    size_type __pos = __p - __base::begin();
+    size_type __to_end = __base::size() - __pos;
+    allocator_type& __a = __base::__alloc();
+    if (__pos < __to_end)
+    {   // insert by shifting things backward
+        if (__n > __front_spare())
+            __add_front_capacity(__n - __front_spare());
+        // __n <= __front_spare()
+        iterator __old_begin = __base::begin();
+        iterator __i = __old_begin;
+        if (__n > __pos)
+        {
+            for (size_type __m = __n - __pos; __m; --__m, --__base::__start_, ++__base::size())
+                __alloc_traits::construct(__a, _VSTD::addressof(*--__i), __v);
+            __n = __pos;
+        }
+        if (__n > 0)
+        {
+            const_pointer __vt = pointer_traits<const_pointer>::pointer_to(__v);
+            iterator __obn = __old_begin + __n;
+            __move_construct_backward_and_check(__old_begin, __obn, __i, __vt);
+            if (__n < __pos)
+                __old_begin = __move_and_check(__obn, __old_begin + __pos, __old_begin, __vt);
+            _VSTD::fill_n(__old_begin, __n, *__vt);
+        }
+    }
+    else
+    {   // insert by shifting things forward
+        size_type __back_capacity = __back_spare();
+        if (__n > __back_capacity)
+            __add_back_capacity(__n - __back_capacity);
+        // __n <= __back_capacity
+        iterator __old_end = __base::end();
+        iterator __i = __old_end;
+        size_type __de = __base::size() - __pos;
+        if (__n > __de)
+        {
+            for (size_type __m = __n - __de; __m; --__m, (void) ++__i, ++__base::size())
+                __alloc_traits::construct(__a, _VSTD::addressof(*__i), __v);
+            __n = __de;
+        }
+        if (__n > 0)
+        {
+            const_pointer __vt = pointer_traits<const_pointer>::pointer_to(__v);
+            iterator __oen = __old_end - __n;
+            __move_construct_and_check(__oen, __old_end, __i, __vt);
+            if (__n < __de)
+                __old_end = __move_backward_and_check(__old_end - __de, __oen, __old_end, __vt);
+            _VSTD::fill_n(__old_end - __n, __n, *__vt);
+        }
+    }
+    return __base::begin() + __pos;
+}
+
+template <class _Tp, class _Allocator>
+template <class _InputIter>
+typename deque<_Tp, _Allocator>::iterator
+deque<_Tp, _Allocator>::insert(const_iterator __p, _InputIter __f, _InputIter __l,
+                               typename enable_if<__is_cpp17_input_iterator<_InputIter>::value
+                                               &&!__is_cpp17_forward_iterator<_InputIter>::value>::type*)
+{
+    __split_buffer<value_type, allocator_type&> __buf(__base::__alloc());
+    __buf.__construct_at_end(__f, __l);
+    typedef typename __split_buffer<value_type, allocator_type&>::iterator __bi;
+    return insert(__p, move_iterator<__bi>(__buf.begin()), move_iterator<__bi>(__buf.end()));
+}
+
+template <class _Tp, class _Allocator>
+template <class _ForwardIterator>
+typename deque<_Tp, _Allocator>::iterator
+deque<_Tp, _Allocator>::insert(const_iterator __p, _ForwardIterator __f, _ForwardIterator __l,
+                               typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value
+                                               &&!__is_cpp17_bidirectional_iterator<_ForwardIterator>::value>::type*)
+{
+    size_type __n = _VSTD::distance(__f, __l);
+    __split_buffer<value_type, allocator_type&> __buf(__n, 0, __base::__alloc());
+    __buf.__construct_at_end(__f, __l);
+    typedef typename __split_buffer<value_type, allocator_type&>::iterator __fwd;
+    return insert(__p, move_iterator<__fwd>(__buf.begin()), move_iterator<__fwd>(__buf.end()));
+}
+
+template <class _Tp, class _Allocator>
+template <class _BiIter>
+typename deque<_Tp, _Allocator>::iterator
+deque<_Tp, _Allocator>::insert(const_iterator __p, _BiIter __f, _BiIter __l,
+                               typename enable_if<__is_cpp17_bidirectional_iterator<_BiIter>::value>::type*)
+{
+    size_type __n = _VSTD::distance(__f, __l);
+    size_type __pos = __p - __base::begin();
+    size_type __to_end = __base::size() - __pos;
+    allocator_type& __a = __base::__alloc();
+    if (__pos < __to_end)
+    {   // insert by shifting things backward
+        if (__n > __front_spare())
+            __add_front_capacity(__n - __front_spare());
+        // __n <= __front_spare()
+        iterator __old_begin = __base::begin();
+        iterator __i = __old_begin;
+        _BiIter __m = __f;
+        if (__n > __pos)
+        {
+            __m = __pos < __n / 2 ? _VSTD::prev(__l, __pos) : _VSTD::next(__f, __n - __pos);
+            for (_BiIter __j = __m; __j != __f; --__base::__start_, ++__base::size())
+                __alloc_traits::construct(__a, _VSTD::addressof(*--__i), *--__j);
+            __n = __pos;
+        }
+        if (__n > 0)
+        {
+            iterator __obn = __old_begin + __n;
+            for (iterator __j = __obn; __j != __old_begin;)
+            {
+                __alloc_traits::construct(__a, _VSTD::addressof(*--__i), _VSTD::move(*--__j));
+                --__base::__start_;
+                ++__base::size();
+            }
+            if (__n < __pos)
+                __old_begin = _VSTD::move(__obn, __old_begin + __pos, __old_begin);
+            _VSTD::copy(__m, __l, __old_begin);
+        }
+    }
+    else
+    {   // insert by shifting things forward
+        size_type __back_capacity = __back_spare();
+        if (__n > __back_capacity)
+            __add_back_capacity(__n - __back_capacity);
+        // __n <= __back_capacity
+        iterator __old_end = __base::end();
+        iterator __i = __old_end;
+        _BiIter __m = __l;
+        size_type __de = __base::size() - __pos;
+        if (__n > __de)
+        {
+            __m = __de < __n / 2 ? _VSTD::next(__f, __de) : _VSTD::prev(__l, __n - __de);
+            for (_BiIter __j = __m; __j != __l; ++__i, (void) ++__j, ++__base::size())
+                __alloc_traits::construct(__a, _VSTD::addressof(*__i), *__j);
+            __n = __de;
+        }
+        if (__n > 0)
+        {
+            iterator __oen = __old_end - __n;
+            for (iterator __j = __oen; __j != __old_end; ++__i, (void) ++__j, ++__base::size())
+                __alloc_traits::construct(__a, _VSTD::addressof(*__i), _VSTD::move(*__j));
+            if (__n < __de)
+                __old_end = _VSTD::move_backward(__old_end - __de, __oen, __old_end);
+            _VSTD::copy_backward(__f, __m, __old_end);
+        }
+    }
+    return __base::begin() + __pos;
+}
+
+template <class _Tp, class _Allocator>
+template <class _InpIter>
+void
+deque<_Tp, _Allocator>::__append(_InpIter __f, _InpIter __l,
+                                 typename enable_if<__is_cpp17_input_iterator<_InpIter>::value &&
+                                                   !__is_cpp17_forward_iterator<_InpIter>::value>::type*)
+{
+    for (; __f != __l; ++__f)
+#ifdef _LIBCPP_CXX03_LANG
+        push_back(*__f);
+#else
+        emplace_back(*__f);
+#endif
+}
+
+template <class _Tp, class _Allocator>
+template <class _ForIter>
+void
+deque<_Tp, _Allocator>::__append(_ForIter __f, _ForIter __l,
+                                 typename enable_if<__is_cpp17_forward_iterator<_ForIter>::value>::type*)
+{
+    size_type __n = _VSTD::distance(__f, __l);
+    allocator_type& __a = __base::__alloc();
+    size_type __back_capacity = __back_spare();
+    if (__n > __back_capacity)
+        __add_back_capacity(__n - __back_capacity);
+    // __n <= __back_capacity
+    for (__deque_block_range __br : __deque_range(__base::end(), __base::end() + __n)) {
+      _ConstructTransaction __tx(this, __br);
+      for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_, (void)++__f) {
+        __alloc_traits::construct(__a, _VSTD::__to_address(__tx.__pos_), *__f);
+      }
+    }
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::__append(size_type __n)
+{
+    allocator_type& __a = __base::__alloc();
+    size_type __back_capacity = __back_spare();
+    if (__n > __back_capacity)
+        __add_back_capacity(__n - __back_capacity);
+    // __n <= __back_capacity
+    for (__deque_block_range __br : __deque_range(__base::end(), __base::end() + __n)) {
+      _ConstructTransaction __tx(this, __br);
+      for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_) {
+        __alloc_traits::construct(__a, _VSTD::__to_address(__tx.__pos_));
+      }
+    }
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::__append(size_type __n, const value_type& __v)
+{
+    allocator_type& __a = __base::__alloc();
+    size_type __back_capacity = __back_spare();
+    if (__n > __back_capacity)
+        __add_back_capacity(__n - __back_capacity);
+    // __n <= __back_capacity
+    for (__deque_block_range __br : __deque_range(__base::end(), __base::end() + __n)) {
+      _ConstructTransaction __tx(this, __br);
+      for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_) {
+        __alloc_traits::construct(__a, _VSTD::__to_address(__tx.__pos_), __v);
+      }
+    }
+
+}
+
+// Create front capacity for one block of elements.
+// Strong guarantee.  Either do it or don't touch anything.
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::__add_front_capacity()
+{
+    allocator_type& __a = __base::__alloc();
+    if (__back_spare() >= size_type(__base::__block_size))
+    {
+        __base::__start_ += __base::__block_size;
+        pointer __pt = __base::__map_.back();
+        __base::__map_.pop_back();
+        __base::__map_.push_front(__pt);
+    }
+    // Else if __base::__map_.size() < __base::__map_.capacity() then we need to allocate 1 buffer
+    else if (__base::__map_.size() < __base::__map_.capacity())
+    {   // we can put the new buffer into the map, but don't shift things around
+        // until all buffers are allocated.  If we throw, we don't need to fix
+        // anything up (any added buffers are undetectible)
+        if (__base::__map_.__front_spare() > 0)
+            __base::__map_.push_front(__alloc_traits::allocate(__a, __base::__block_size));
+        else
+        {
+            __base::__map_.push_back(__alloc_traits::allocate(__a, __base::__block_size));
+            // Done allocating, reorder capacity
+            pointer __pt = __base::__map_.back();
+            __base::__map_.pop_back();
+            __base::__map_.push_front(__pt);
+        }
+        __base::__start_ = __base::__map_.size() == 1 ?
+                               __base::__block_size / 2 :
+                               __base::__start_ + __base::__block_size;
+    }
+    // Else need to allocate 1 buffer, *and* we need to reallocate __map_.
+    else
+    {
+        __split_buffer<pointer, typename __base::__pointer_allocator&>
+            __buf(max<size_type>(2 * __base::__map_.capacity(), 1),
+                  0, __base::__map_.__alloc());
+
+        typedef __allocator_destructor<_Allocator> _Dp;
+        unique_ptr<pointer, _Dp> __hold(
+            __alloc_traits::allocate(__a, __base::__block_size),
+                _Dp(__a, __base::__block_size));
+        __buf.push_back(__hold.get());
+        __hold.release();
+
+        for (typename __base::__map_pointer __i = __base::__map_.begin();
+                __i != __base::__map_.end(); ++__i)
+            __buf.push_back(*__i);
+        _VSTD::swap(__base::__map_.__first_, __buf.__first_);
+        _VSTD::swap(__base::__map_.__begin_, __buf.__begin_);
+        _VSTD::swap(__base::__map_.__end_, __buf.__end_);
+        _VSTD::swap(__base::__map_.__end_cap(), __buf.__end_cap());
+        __base::__start_ = __base::__map_.size() == 1 ?
+                               __base::__block_size / 2 :
+                               __base::__start_ + __base::__block_size;
+    }
+}
+
+// Create front capacity for __n elements.
+// Strong guarantee.  Either do it or don't touch anything.
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::__add_front_capacity(size_type __n)
+{
+    allocator_type& __a = __base::__alloc();
+    size_type __nb = __recommend_blocks(__n + __base::__map_.empty());
+    // Number of unused blocks at back:
+    size_type __back_capacity = __back_spare() / __base::__block_size;
+    __back_capacity = _VSTD::min(__back_capacity, __nb);  // don't take more than you need
+    __nb -= __back_capacity;  // number of blocks need to allocate
+    // If __nb == 0, then we have sufficient capacity.
+    if (__nb == 0)
+    {
+        __base::__start_ += __base::__block_size * __back_capacity;
+        for (; __back_capacity > 0; --__back_capacity)
+        {
+            pointer __pt = __base::__map_.back();
+            __base::__map_.pop_back();
+            __base::__map_.push_front(__pt);
+        }
+    }
+    // Else if __nb <= __map_.capacity() - __map_.size() then we need to allocate __nb buffers
+    else if (__nb <= __base::__map_.capacity() - __base::__map_.size())
+    {   // we can put the new buffers into the map, but don't shift things around
+        // until all buffers are allocated.  If we throw, we don't need to fix
+        // anything up (any added buffers are undetectible)
+        for (; __nb > 0; --__nb, __base::__start_ += __base::__block_size - (__base::__map_.size() == 1))
+        {
+            if (__base::__map_.__front_spare() == 0)
+                break;
+            __base::__map_.push_front(__alloc_traits::allocate(__a, __base::__block_size));
+        }
+        for (; __nb > 0; --__nb, ++__back_capacity)
+            __base::__map_.push_back(__alloc_traits::allocate(__a, __base::__block_size));
+        // Done allocating, reorder capacity
+        __base::__start_ += __back_capacity * __base::__block_size;
+        for (; __back_capacity > 0; --__back_capacity)
+        {
+            pointer __pt = __base::__map_.back();
+            __base::__map_.pop_back();
+            __base::__map_.push_front(__pt);
+        }
+    }
+    // Else need to allocate __nb buffers, *and* we need to reallocate __map_.
+    else
+    {
+        size_type __ds = (__nb + __back_capacity) * __base::__block_size - __base::__map_.empty();
+        __split_buffer<pointer, typename __base::__pointer_allocator&>
+            __buf(max<size_type>(2* __base::__map_.capacity(),
+                                 __nb + __base::__map_.size()),
+                  0, __base::__map_.__alloc());
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (; __nb > 0; --__nb)
+                __buf.push_back(__alloc_traits::allocate(__a, __base::__block_size));
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            for (typename __base::__map_pointer __i = __buf.begin();
+                    __i != __buf.end(); ++__i)
+                __alloc_traits::deallocate(__a, *__i, __base::__block_size);
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        for (; __back_capacity > 0; --__back_capacity)
+        {
+            __buf.push_back(__base::__map_.back());
+            __base::__map_.pop_back();
+        }
+        for (typename __base::__map_pointer __i = __base::__map_.begin();
+                __i != __base::__map_.end(); ++__i)
+            __buf.push_back(*__i);
+        _VSTD::swap(__base::__map_.__first_, __buf.__first_);
+        _VSTD::swap(__base::__map_.__begin_, __buf.__begin_);
+        _VSTD::swap(__base::__map_.__end_, __buf.__end_);
+        _VSTD::swap(__base::__map_.__end_cap(), __buf.__end_cap());
+        __base::__start_ += __ds;
+    }
+}
+
+// Create back capacity for one block of elements.
+// Strong guarantee.  Either do it or don't touch anything.
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::__add_back_capacity()
+{
+    allocator_type& __a = __base::__alloc();
+    if (__front_spare() >= size_type(__base::__block_size))
+    {
+        __base::__start_ -= __base::__block_size;
+        pointer __pt = __base::__map_.front();
+        __base::__map_.pop_front();
+        __base::__map_.push_back(__pt);
+    }
+    // Else if __nb <= __map_.capacity() - __map_.size() then we need to allocate __nb buffers
+    else if (__base::__map_.size() < __base::__map_.capacity())
+    {   // we can put the new buffer into the map, but don't shift things around
+        // until it is allocated.  If we throw, we don't need to fix
+        // anything up (any added buffers are undetectible)
+        if (__base::__map_.__back_spare() != 0)
+            __base::__map_.push_back(__alloc_traits::allocate(__a, __base::__block_size));
+        else
+        {
+            __base::__map_.push_front(__alloc_traits::allocate(__a, __base::__block_size));
+            // Done allocating, reorder capacity
+            pointer __pt = __base::__map_.front();
+            __base::__map_.pop_front();
+            __base::__map_.push_back(__pt);
+        }
+    }
+    // Else need to allocate 1 buffer, *and* we need to reallocate __map_.
+    else
+    {
+        __split_buffer<pointer, typename __base::__pointer_allocator&>
+            __buf(max<size_type>(2* __base::__map_.capacity(), 1),
+                  __base::__map_.size(),
+                  __base::__map_.__alloc());
+
+        typedef __allocator_destructor<_Allocator> _Dp;
+        unique_ptr<pointer, _Dp> __hold(
+            __alloc_traits::allocate(__a, __base::__block_size),
+                _Dp(__a, __base::__block_size));
+        __buf.push_back(__hold.get());
+        __hold.release();
+
+        for (typename __base::__map_pointer __i = __base::__map_.end();
+                __i != __base::__map_.begin();)
+            __buf.push_front(*--__i);
+        _VSTD::swap(__base::__map_.__first_, __buf.__first_);
+        _VSTD::swap(__base::__map_.__begin_, __buf.__begin_);
+        _VSTD::swap(__base::__map_.__end_, __buf.__end_);
+        _VSTD::swap(__base::__map_.__end_cap(), __buf.__end_cap());
+    }
+}
+
+// Create back capacity for __n elements.
+// Strong guarantee.  Either do it or don't touch anything.
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::__add_back_capacity(size_type __n)
+{
+    allocator_type& __a = __base::__alloc();
+    size_type __nb = __recommend_blocks(__n + __base::__map_.empty());
+    // Number of unused blocks at front:
+    size_type __front_capacity = __front_spare() / __base::__block_size;
+    __front_capacity = _VSTD::min(__front_capacity, __nb);  // don't take more than you need
+    __nb -= __front_capacity;  // number of blocks need to allocate
+    // If __nb == 0, then we have sufficient capacity.
+    if (__nb == 0)
+    {
+        __base::__start_ -= __base::__block_size * __front_capacity;
+        for (; __front_capacity > 0; --__front_capacity)
+        {
+            pointer __pt = __base::__map_.front();
+            __base::__map_.pop_front();
+            __base::__map_.push_back(__pt);
+        }
+    }
+    // Else if __nb <= __map_.capacity() - __map_.size() then we need to allocate __nb buffers
+    else if (__nb <= __base::__map_.capacity() - __base::__map_.size())
+    {   // we can put the new buffers into the map, but don't shift things around
+        // until all buffers are allocated.  If we throw, we don't need to fix
+        // anything up (any added buffers are undetectible)
+        for (; __nb > 0; --__nb)
+        {
+            if (__base::__map_.__back_spare() == 0)
+                break;
+            __base::__map_.push_back(__alloc_traits::allocate(__a, __base::__block_size));
+        }
+        for (; __nb > 0; --__nb, ++__front_capacity, __base::__start_ +=
+                                 __base::__block_size - (__base::__map_.size() == 1))
+            __base::__map_.push_front(__alloc_traits::allocate(__a, __base::__block_size));
+        // Done allocating, reorder capacity
+        __base::__start_ -= __base::__block_size * __front_capacity;
+        for (; __front_capacity > 0; --__front_capacity)
+        {
+            pointer __pt = __base::__map_.front();
+            __base::__map_.pop_front();
+            __base::__map_.push_back(__pt);
+        }
+    }
+    // Else need to allocate __nb buffers, *and* we need to reallocate __map_.
+    else
+    {
+        size_type __ds = __front_capacity * __base::__block_size;
+        __split_buffer<pointer, typename __base::__pointer_allocator&>
+            __buf(max<size_type>(2* __base::__map_.capacity(),
+                                 __nb + __base::__map_.size()),
+                  __base::__map_.size() - __front_capacity,
+                  __base::__map_.__alloc());
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (; __nb > 0; --__nb)
+                __buf.push_back(__alloc_traits::allocate(__a, __base::__block_size));
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            for (typename __base::__map_pointer __i = __buf.begin();
+                    __i != __buf.end(); ++__i)
+                __alloc_traits::deallocate(__a, *__i, __base::__block_size);
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        for (; __front_capacity > 0; --__front_capacity)
+        {
+            __buf.push_back(__base::__map_.front());
+            __base::__map_.pop_front();
+        }
+        for (typename __base::__map_pointer __i = __base::__map_.end();
+                __i != __base::__map_.begin();)
+            __buf.push_front(*--__i);
+        _VSTD::swap(__base::__map_.__first_, __buf.__first_);
+        _VSTD::swap(__base::__map_.__begin_, __buf.__begin_);
+        _VSTD::swap(__base::__map_.__end_, __buf.__end_);
+        _VSTD::swap(__base::__map_.__end_cap(), __buf.__end_cap());
+        __base::__start_ -= __ds;
+    }
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::pop_front()
+{
+    allocator_type& __a = __base::__alloc();
+    __alloc_traits::destroy(__a, _VSTD::__to_address(*(__base::__map_.begin() +
+                                                    __base::__start_ / __base::__block_size) +
+                                                    __base::__start_ % __base::__block_size));
+    --__base::size();
+    ++__base::__start_;
+    __maybe_remove_front_spare();
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::pop_back()
+{
+    _LIBCPP_ASSERT(!empty(), "deque::pop_back called on an empty deque");
+    allocator_type& __a = __base::__alloc();
+    size_type __p = __base::size() + __base::__start_ - 1;
+    __alloc_traits::destroy(__a, _VSTD::__to_address(*(__base::__map_.begin() +
+                                                    __p / __base::__block_size) +
+                                                    __p % __base::__block_size));
+    --__base::size();
+    __maybe_remove_back_spare();
+}
+
+// move assign [__f, __l) to [__r, __r + (__l-__f)).
+// If __vt points into [__f, __l), then subtract (__f - __r) from __vt.
+template <class _Tp, class _Allocator>
+typename deque<_Tp, _Allocator>::iterator
+deque<_Tp, _Allocator>::__move_and_check(iterator __f, iterator __l, iterator __r,
+                                         const_pointer& __vt)
+{
+    // as if
+    //   for (; __f != __l; ++__f, ++__r)
+    //       *__r = _VSTD::move(*__f);
+    difference_type __n = __l - __f;
+    while (__n > 0)
+    {
+        pointer __fb = __f.__ptr_;
+        pointer __fe = *__f.__m_iter_ + __base::__block_size;
+        difference_type __bs = __fe - __fb;
+        if (__bs > __n)
+        {
+            __bs = __n;
+            __fe = __fb + __bs;
+        }
+        if (__fb <= __vt && __vt < __fe)
+            __vt = (const_iterator(static_cast<__map_const_pointer>(__f.__m_iter_), __vt) -= __f - __r).__ptr_;
+        __r = _VSTD::move(__fb, __fe, __r);
+        __n -= __bs;
+        __f += __bs;
+    }
+    return __r;
+}
+
+// move assign [__f, __l) to [__r - (__l-__f), __r) backwards.
+// If __vt points into [__f, __l), then add (__r - __l) to __vt.
+template <class _Tp, class _Allocator>
+typename deque<_Tp, _Allocator>::iterator
+deque<_Tp, _Allocator>::__move_backward_and_check(iterator __f, iterator __l, iterator __r,
+                                                  const_pointer& __vt)
+{
+    // as if
+    //   while (__f != __l)
+    //       *--__r = _VSTD::move(*--__l);
+    difference_type __n = __l - __f;
+    while (__n > 0)
+    {
+        --__l;
+        pointer __lb = *__l.__m_iter_;
+        pointer __le = __l.__ptr_ + 1;
+        difference_type __bs = __le - __lb;
+        if (__bs > __n)
+        {
+            __bs = __n;
+            __lb = __le - __bs;
+        }
+        if (__lb <= __vt && __vt < __le)
+            __vt = (const_iterator(static_cast<__map_const_pointer>(__l.__m_iter_), __vt) += __r - __l - 1).__ptr_;
+        __r = _VSTD::move_backward(__lb, __le, __r);
+        __n -= __bs;
+        __l -= __bs - 1;
+    }
+    return __r;
+}
+
+// move construct [__f, __l) to [__r, __r + (__l-__f)).
+// If __vt points into [__f, __l), then add (__r - __f) to __vt.
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::__move_construct_and_check(iterator __f, iterator __l,
+                                                   iterator __r, const_pointer& __vt)
+{
+    allocator_type& __a = __base::__alloc();
+    // as if
+    //   for (; __f != __l; ++__r, ++__f, ++__base::size())
+    //       __alloc_traits::construct(__a, _VSTD::addressof(*__r), _VSTD::move(*__f));
+    difference_type __n = __l - __f;
+    while (__n > 0)
+    {
+        pointer __fb = __f.__ptr_;
+        pointer __fe = *__f.__m_iter_ + __base::__block_size;
+        difference_type __bs = __fe - __fb;
+        if (__bs > __n)
+        {
+            __bs = __n;
+            __fe = __fb + __bs;
+        }
+        if (__fb <= __vt && __vt < __fe)
+            __vt = (const_iterator(static_cast<__map_const_pointer>(__f.__m_iter_), __vt) += __r - __f).__ptr_;
+        for (; __fb != __fe; ++__fb, ++__r, ++__base::size())
+            __alloc_traits::construct(__a, _VSTD::addressof(*__r), _VSTD::move(*__fb));
+        __n -= __bs;
+        __f += __bs;
+    }
+}
+
+// move construct [__f, __l) to [__r - (__l-__f), __r) backwards.
+// If __vt points into [__f, __l), then subtract (__l - __r) from __vt.
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::__move_construct_backward_and_check(iterator __f, iterator __l,
+                                                            iterator __r, const_pointer& __vt)
+{
+    allocator_type& __a = __base::__alloc();
+    // as if
+    //   for (iterator __j = __l; __j != __f;)
+    //   {
+    //       __alloc_traitsconstruct(__a, _VSTD::addressof(*--__r), _VSTD::move(*--__j));
+    //       --__base::__start_;
+    //       ++__base::size();
+    //   }
+    difference_type __n = __l - __f;
+    while (__n > 0)
+    {
+        --__l;
+        pointer __lb = *__l.__m_iter_;
+        pointer __le = __l.__ptr_ + 1;
+        difference_type __bs = __le - __lb;
+        if (__bs > __n)
+        {
+            __bs = __n;
+            __lb = __le - __bs;
+        }
+        if (__lb <= __vt && __vt < __le)
+            __vt = (const_iterator(static_cast<__map_const_pointer>(__l.__m_iter_), __vt) -= __l - __r + 1).__ptr_;
+        while (__le != __lb)
+        {
+            __alloc_traits::construct(__a, _VSTD::addressof(*--__r), _VSTD::move(*--__le));
+            --__base::__start_;
+            ++__base::size();
+        }
+        __n -= __bs;
+        __l -= __bs - 1;
+    }
+}
+
+template <class _Tp, class _Allocator>
+typename deque<_Tp, _Allocator>::iterator
+deque<_Tp, _Allocator>::erase(const_iterator __f)
+{
+    iterator __b = __base::begin();
+    difference_type __pos = __f - __b;
+    iterator __p = __b + __pos;
+    allocator_type& __a = __base::__alloc();
+    if (static_cast<size_t>(__pos) <= (__base::size() - 1) / 2)
+    {   // erase from front
+        _VSTD::move_backward(__b, __p, _VSTD::next(__p));
+        __alloc_traits::destroy(__a, _VSTD::addressof(*__b));
+        --__base::size();
+        ++__base::__start_;
+        __maybe_remove_front_spare();
+    }
+    else
+    {   // erase from back
+        iterator __i = _VSTD::move(_VSTD::next(__p), __base::end(), __p);
+        __alloc_traits::destroy(__a, _VSTD::addressof(*__i));
+        --__base::size();
+        __maybe_remove_back_spare();
+    }
+    return __base::begin() + __pos;
+}
+
+template <class _Tp, class _Allocator>
+typename deque<_Tp, _Allocator>::iterator
+deque<_Tp, _Allocator>::erase(const_iterator __f, const_iterator __l)
+{
+    difference_type __n = __l - __f;
+    iterator __b = __base::begin();
+    difference_type __pos = __f - __b;
+    iterator __p = __b + __pos;
+    if (__n > 0)
+    {
+        allocator_type& __a = __base::__alloc();
+        if (static_cast<size_t>(__pos) <= (__base::size() - __n) / 2)
+        {   // erase from front
+            iterator __i = _VSTD::move_backward(__b, __p, __p + __n);
+            for (; __b != __i; ++__b)
+                __alloc_traits::destroy(__a, _VSTD::addressof(*__b));
+            __base::size() -= __n;
+            __base::__start_ += __n;
+            while (__maybe_remove_front_spare()) {
+            }
+        }
+        else
+        {   // erase from back
+            iterator __i = _VSTD::move(__p + __n, __base::end(), __p);
+            for (iterator __e = __base::end(); __i != __e; ++__i)
+                __alloc_traits::destroy(__a, _VSTD::addressof(*__i));
+            __base::size() -= __n;
+            while (__maybe_remove_back_spare()) {
+            }
+        }
+    }
+    return __base::begin() + __pos;
+}
+
+template <class _Tp, class _Allocator>
+void
+deque<_Tp, _Allocator>::__erase_to_end(const_iterator __f)
+{
+    iterator __e = __base::end();
+    difference_type __n = __e - __f;
+    if (__n > 0)
+    {
+        allocator_type& __a = __base::__alloc();
+        iterator __b = __base::begin();
+        difference_type __pos = __f - __b;
+        for (iterator __p = __b + __pos; __p != __e; ++__p)
+            __alloc_traits::destroy(__a, _VSTD::addressof(*__p));
+        __base::size() -= __n;
+        while (__maybe_remove_back_spare()) {
+        }
+    }
+}
+
+template <class _Tp, class _Allocator>
+inline
+void
+deque<_Tp, _Allocator>::swap(deque& __c)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<allocator_type>::value)
+#endif
+{
+    __base::swap(__c);
+}
+
+template <class _Tp, class _Allocator>
+inline
+void
+deque<_Tp, _Allocator>::clear() _NOEXCEPT
+{
+    __base::clear();
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const deque<_Tp, _Allocator>& __x, const deque<_Tp, _Allocator>& __y)
+{
+    const typename deque<_Tp, _Allocator>::size_type __sz = __x.size();
+    return __sz == __y.size() && _VSTD::equal(__x.begin(), __x.end(), __y.begin());
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const deque<_Tp, _Allocator>& __x, const deque<_Tp, _Allocator>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const deque<_Tp, _Allocator>& __x, const deque<_Tp, _Allocator>& __y)
+{
+    return _VSTD::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const deque<_Tp, _Allocator>& __x, const deque<_Tp, _Allocator>& __y)
+{
+    return __y < __x;
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const deque<_Tp, _Allocator>& __x, const deque<_Tp, _Allocator>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const deque<_Tp, _Allocator>& __x, const deque<_Tp, _Allocator>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(deque<_Tp, _Allocator>& __x, deque<_Tp, _Allocator>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Tp, class _Allocator, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY typename deque<_Tp, _Allocator>::size_type
+erase(deque<_Tp, _Allocator>& __c, const _Up& __v) {
+  auto __old_size = __c.size();
+  __c.erase(_VSTD::remove(__c.begin(), __c.end(), __v), __c.end());
+  return __old_size - __c.size();
+}
+
+template <class _Tp, class _Allocator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY typename deque<_Tp, _Allocator>::size_type
+erase_if(deque<_Tp, _Allocator>& __c, _Predicate __pred) {
+  auto __old_size = __c.size();
+  __c.erase(_VSTD::remove_if(__c.begin(), __c.end(), __pred), __c.end());
+  return __old_size - __c.size();
+}
+#endif
+
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_DEQUE
diff --git a/contrib/libs/cxxsupp/libcxx/include/errno.h b/contrib/libs/cxxsupp/libcxx/include/errno.h
new file mode 100644
index 00000000000..a00707aa4c3
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/errno.h
@@ -0,0 +1,410 @@
+// -*- C++ -*-
+//===-------------------------- errno.h -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_ERRNO_H
+#define _LIBCPP_ERRNO_H
+
+/*
+    errno.h synopsis
+
+Macros:
+
+    EDOM
+    EILSEQ  // C99
+    ERANGE
+    errno
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+// errno is defined in several files so we can't use #ifndef errno here
+#ifdef errno
+// undefine errno to avoid substitution in errno.h include file name.
+#pragma push_macro("errno")
+#undef errno
+#include _LIBCPP_UCRT_INCLUDE(errno.h)
+#pragma pop_macro("errno")
+#else
+#include _LIBCPP_UCRT_INCLUDE(errno.h)
+#endif
+#else
+#include_next <errno.h>
+#endif
+
+#ifdef __cplusplus
+
+#if !defined(EOWNERDEAD) || !defined(ENOTRECOVERABLE)
+
+#ifdef ELAST
+
+static const int __elast1 = ELAST+1;
+static const int __elast2 = ELAST+2;
+
+#else
+
+static const int __elast1 = 104;
+static const int __elast2 = 105;
+
+#endif
+
+#ifdef ENOTRECOVERABLE
+
+#define EOWNERDEAD __elast1
+
+#ifdef ELAST
+#undef ELAST
+#define ELAST EOWNERDEAD
+#endif
+
+#elif defined(EOWNERDEAD)
+
+#define ENOTRECOVERABLE __elast1
+#ifdef ELAST
+#undef ELAST
+#define ELAST ENOTRECOVERABLE
+#endif
+
+#else  // defined(EOWNERDEAD)
+
+#define EOWNERDEAD __elast1
+#define ENOTRECOVERABLE __elast2
+#ifdef ELAST
+#undef ELAST
+#define ELAST ENOTRECOVERABLE
+#endif
+
+#endif // defined(EOWNERDEAD)
+
+#endif // !defined(EOWNERDEAD) || !defined(ENOTRECOVERABLE)
+
+//  supply errno values likely to be missing, particularly on Windows
+
+#ifndef EAFNOSUPPORT
+#define EAFNOSUPPORT 9901
+#endif
+
+#ifndef EADDRINUSE
+#define EADDRINUSE 9902
+#endif
+
+#ifndef EADDRNOTAVAIL
+#define EADDRNOTAVAIL 9903
+#endif
+
+#ifndef EISCONN
+#define EISCONN 9904
+#endif
+
+#ifndef EBADMSG
+#define EBADMSG 9905
+#endif
+
+#ifndef ECONNABORTED
+#define ECONNABORTED 9906
+#endif
+
+#ifndef EALREADY
+#define EALREADY 9907
+#endif
+
+#ifndef ECONNREFUSED
+#define ECONNREFUSED 9908
+#endif
+
+#ifndef ECONNRESET
+#define ECONNRESET 9909
+#endif
+
+#ifndef EDESTADDRREQ
+#define EDESTADDRREQ 9910
+#endif
+
+#ifndef EHOSTUNREACH
+#define EHOSTUNREACH 9911
+#endif
+
+#ifndef EIDRM
+#define EIDRM 9912
+#endif
+
+#ifndef EMSGSIZE
+#define EMSGSIZE 9913
+#endif
+
+#ifndef ENETDOWN
+#define ENETDOWN 9914
+#endif
+
+#ifndef ENETRESET
+#define ENETRESET 9915
+#endif
+
+#ifndef ENETUNREACH
+#define ENETUNREACH 9916
+#endif
+
+#ifndef ENOBUFS
+#define ENOBUFS 9917
+#endif
+
+#ifndef ENOLINK
+#define ENOLINK 9918
+#endif
+
+#ifndef ENODATA
+#define ENODATA 9919
+#endif
+
+#ifndef ENOMSG
+#define ENOMSG 9920
+#endif
+
+#ifndef ENOPROTOOPT
+#define ENOPROTOOPT 9921
+#endif
+
+#ifndef ENOSR
+#define ENOSR 9922
+#endif
+
+#ifndef ENOTSOCK
+#define ENOTSOCK 9923
+#endif
+
+#ifndef ENOSTR
+#define ENOSTR 9924
+#endif
+
+#ifndef ENOTCONN
+#define ENOTCONN 9925
+#endif
+
+#ifndef ENOTSUP
+#define ENOTSUP 9926
+#endif
+
+#ifndef ECANCELED
+#define ECANCELED 9927
+#endif
+
+#ifndef EINPROGRESS
+#define EINPROGRESS 9928
+#endif
+
+#ifndef EOPNOTSUPP
+#define EOPNOTSUPP 9929
+#endif
+
+#ifndef EWOULDBLOCK
+#define EWOULDBLOCK 9930
+#endif
+
+#ifndef EOWNERDEAD
+#define EOWNERDEAD  9931
+#endif
+
+#ifndef EPROTO
+#define EPROTO 9932
+#endif
+
+#ifndef EPROTONOSUPPORT
+#define EPROTONOSUPPORT 9933
+#endif
+
+#ifndef ENOTRECOVERABLE
+#define ENOTRECOVERABLE 9934
+#endif
+
+#ifndef ETIME
+#define ETIME 9935
+#endif
+
+#ifndef ETXTBSY
+#define ETXTBSY 9936
+#endif
+
+#ifndef ETIMEDOUT
+#define ETIMEDOUT 9938
+#endif
+
+#ifndef ELOOP
+#define ELOOP 9939
+#endif
+
+#ifndef EOVERFLOW
+#define EOVERFLOW 9940
+#endif
+
+#ifndef EPROTOTYPE
+#define EPROTOTYPE 9941
+#endif
+
+#ifndef ENOSYS
+#define ENOSYS 9942
+#endif
+
+#ifndef EINVAL
+#define EINVAL 9943
+#endif
+
+#ifndef ERANGE
+#define ERANGE 9944
+#endif
+
+#ifndef EILSEQ
+#define EILSEQ 9945
+#endif
+
+//  Windows Mobile doesn't appear to define these:
+
+#ifndef E2BIG
+#define E2BIG 9946
+#endif
+
+#ifndef EDOM
+#define EDOM 9947
+#endif
+
+#ifndef EFAULT
+#define EFAULT 9948
+#endif
+
+#ifndef EBADF
+#define EBADF 9949
+#endif
+
+#ifndef EPIPE
+#define EPIPE 9950
+#endif
+
+#ifndef EXDEV
+#define EXDEV 9951
+#endif
+
+#ifndef EBUSY
+#define EBUSY 9952
+#endif
+
+#ifndef ENOTEMPTY
+#define ENOTEMPTY 9953
+#endif
+
+#ifndef ENOEXEC
+#define ENOEXEC 9954
+#endif
+
+#ifndef EEXIST
+#define EEXIST 9955
+#endif
+
+#ifndef EFBIG
+#define EFBIG 9956
+#endif
+
+#ifndef ENAMETOOLONG
+#define ENAMETOOLONG 9957
+#endif
+
+#ifndef ENOTTY
+#define ENOTTY 9958
+#endif
+
+#ifndef EINTR
+#define EINTR 9959
+#endif
+
+#ifndef ESPIPE
+#define ESPIPE 9960
+#endif
+
+#ifndef EIO
+#define EIO 9961
+#endif
+
+#ifndef EISDIR
+#define EISDIR 9962
+#endif
+
+#ifndef ECHILD
+#define ECHILD 9963
+#endif
+
+#ifndef ENOLCK
+#define ENOLCK 9964
+#endif
+
+#ifndef ENOSPC
+#define ENOSPC 9965
+#endif
+
+#ifndef ENXIO
+#define ENXIO 9966
+#endif
+
+#ifndef ENODEV
+#define ENODEV 9967
+#endif
+
+#ifndef ENOENT
+#define ENOENT 9968
+#endif
+
+#ifndef ESRCH
+#define ESRCH 9969
+#endif
+
+#ifndef ENOTDIR
+#define ENOTDIR 9970
+#endif
+
+#ifndef ENOMEM
+#define ENOMEM 9971
+#endif
+
+#ifndef EPERM
+#define EPERM 9972
+#endif
+
+#ifndef EACCES
+#define EACCES 9973
+#endif
+
+#ifndef EROFS
+#define EROFS 9974
+#endif
+
+#ifndef EDEADLK
+#define EDEADLK 9975
+#endif
+
+#ifndef EAGAIN
+#define EAGAIN 9976
+#endif
+
+#ifndef ENFILE
+#define ENFILE 9977
+#endif
+
+#ifndef EMFILE
+#define EMFILE 9978
+#endif
+
+#ifndef EMLINK
+#define EMLINK 9979
+#endif
+
+#endif // __cplusplus
+
+#endif // _LIBCPP_ERRNO_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/exception b/contrib/libs/cxxsupp/libcxx/include/exception
new file mode 100644
index 00000000000..e83e9fee2ec
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/exception
@@ -0,0 +1,308 @@
+// -*- C++ -*-
+//===-------------------------- exception ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXCEPTION
+#define _LIBCPP_EXCEPTION
+
+/*
+    exception synopsis
+
+namespace std
+{
+
+class exception
+{
+public:
+    exception() noexcept;
+    exception(const exception&) noexcept;
+    exception& operator=(const exception&) noexcept;
+    virtual ~exception() noexcept;
+    virtual const char* what() const noexcept;
+};
+
+class bad_exception
+    : public exception
+{
+public:
+    bad_exception() noexcept;
+    bad_exception(const bad_exception&) noexcept;
+    bad_exception& operator=(const bad_exception&) noexcept;
+    virtual ~bad_exception() noexcept;
+    virtual const char* what() const noexcept;
+};
+
+typedef void (*unexpected_handler)();
+unexpected_handler set_unexpected(unexpected_handler  f ) noexcept;
+unexpected_handler get_unexpected() noexcept;
+[[noreturn]] void unexpected();
+
+typedef void (*terminate_handler)();
+terminate_handler set_terminate(terminate_handler  f ) noexcept;
+terminate_handler get_terminate() noexcept;
+[[noreturn]] void terminate() noexcept;
+
+bool uncaught_exception()  noexcept;
+int  uncaught_exceptions() noexcept;  // C++17
+
+typedef unspecified exception_ptr;
+
+exception_ptr current_exception() noexcept;
+void rethrow_exception [[noreturn]] (exception_ptr p);
+template<class E> exception_ptr make_exception_ptr(E e) noexcept;
+
+class nested_exception
+{
+public:
+    nested_exception() noexcept;
+    nested_exception(const nested_exception&) noexcept = default;
+    nested_exception& operator=(const nested_exception&) noexcept = default;
+    virtual ~nested_exception() = default;
+
+    // access functions
+    [[noreturn]] void rethrow_nested() const;
+    exception_ptr nested_ptr() const noexcept;
+};
+
+template <class T> [[noreturn]] void throw_with_nested(T&& t);
+template <class E> void rethrow_if_nested(const E& e);
+
+}  // std
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <__memory/addressof.h>
+#include <cstddef>
+#include <cstdlib>
+#include <type_traits>
+#include <version>
+
+#if defined(_LIBCPP_ABI_VCRUNTIME)
+#include <vcruntime_exception.h>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+namespace std  // purposefully not using versioning namespace
+{
+
+#if !defined(_LIBCPP_ABI_VCRUNTIME)
+class _LIBCPP_EXCEPTION_ABI exception
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY exception() _NOEXCEPT {}
+    _LIBCPP_INLINE_VISIBILITY exception(const exception&) _NOEXCEPT = default;
+
+    virtual ~exception() _NOEXCEPT;
+    virtual const char* what() const _NOEXCEPT;
+};
+
+class _LIBCPP_EXCEPTION_ABI bad_exception
+    : public exception
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY bad_exception() _NOEXCEPT {}
+    virtual ~bad_exception() _NOEXCEPT;
+    virtual const char* what() const _NOEXCEPT;
+};
+#endif // !_LIBCPP_ABI_VCRUNTIME
+
+#if _LIBCPP_STD_VER <= 14 \
+    || defined(_LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS) \
+    || defined(_LIBCPP_BUILDING_LIBRARY)
+typedef void (*unexpected_handler)();
+_LIBCPP_FUNC_VIS unexpected_handler set_unexpected(unexpected_handler) _NOEXCEPT;
+_LIBCPP_FUNC_VIS unexpected_handler get_unexpected() _NOEXCEPT;
+_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void unexpected();
+#endif
+
+typedef void (*terminate_handler)();
+_LIBCPP_FUNC_VIS terminate_handler set_terminate(terminate_handler) _NOEXCEPT;
+_LIBCPP_FUNC_VIS terminate_handler get_terminate() _NOEXCEPT;
+_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void terminate() _NOEXCEPT;
+
+_LIBCPP_FUNC_VIS bool uncaught_exception() _NOEXCEPT;
+_LIBCPP_FUNC_VIS _LIBCPP_AVAILABILITY_UNCAUGHT_EXCEPTIONS int uncaught_exceptions() _NOEXCEPT;
+
+class _LIBCPP_TYPE_VIS exception_ptr;
+
+_LIBCPP_FUNC_VIS exception_ptr current_exception() _NOEXCEPT;
+_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void rethrow_exception(exception_ptr);
+
+class _LIBCPP_TYPE_VIS exception_ptr
+{
+    void* __ptr_;
+public:
+    _LIBCPP_INLINE_VISIBILITY exception_ptr() _NOEXCEPT : __ptr_() {}
+    _LIBCPP_INLINE_VISIBILITY exception_ptr(nullptr_t) _NOEXCEPT : __ptr_() {}
+
+    exception_ptr(const exception_ptr&) _NOEXCEPT;
+    exception_ptr& operator=(const exception_ptr&) _NOEXCEPT;
+    ~exception_ptr() _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY explicit operator bool() const _NOEXCEPT
+    {return __ptr_ != nullptr;}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
+        {return __x.__ptr_ == __y.__ptr_;}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
+        {return !(__x == __y);}
+
+    friend _LIBCPP_FUNC_VIS void swap(exception_ptr& __x, exception_ptr& __y) _NOEXCEPT
+    {
+        void* __tmp = __x.__ptr_;
+        __x.__ptr_ = __y.__ptr_;
+        __y.__ptr_ = __tmp;
+    }
+
+    friend _LIBCPP_FUNC_VIS exception_ptr current_exception() _NOEXCEPT;
+    friend _LIBCPP_FUNC_VIS void rethrow_exception(exception_ptr);
+};
+
+#ifndef _LIBCPP_ABI_MICROSOFT
+
+template<class _Ep>
+_LIBCPP_INLINE_VISIBILITY exception_ptr
+make_exception_ptr(_Ep __e) _NOEXCEPT
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+        throw __e;
+    }
+    catch (...)
+    {
+        return current_exception();
+    }
+#else
+    ((void)__e);
+    _VSTD::abort();
+#endif
+}
+
+#else // _LIBCPP_ABI_MICROSOFT
+
+_LIBCPP_FUNC_VIS exception_ptr __copy_exception_ptr(void *__exception, const void* __ptr);
+
+// This is a built-in template function which automagically extracts the required
+// information.
+template <class _E> void *__GetExceptionInfo(_E);
+
+template<class _Ep>
+exception_ptr
+make_exception_ptr(_Ep __e) _NOEXCEPT
+{
+  return __copy_exception_ptr(_VSTD::addressof(__e), __GetExceptionInfo(__e));
+}
+
+#endif // _LIBCPP_ABI_MICROSOFT
+// nested_exception
+
+class _LIBCPP_EXCEPTION_ABI nested_exception
+{
+    exception_ptr __ptr_;
+public:
+    nested_exception() _NOEXCEPT;
+//     nested_exception(const nested_exception&) noexcept = default;
+//     nested_exception& operator=(const nested_exception&) noexcept = default;
+    virtual ~nested_exception() _NOEXCEPT;
+
+    // access functions
+    _LIBCPP_NORETURN void rethrow_nested() const;
+    _LIBCPP_INLINE_VISIBILITY exception_ptr nested_ptr() const _NOEXCEPT {return __ptr_;}
+};
+
+template <class _Tp>
+struct __nested
+    : public _Tp,
+      public nested_exception
+{
+    _LIBCPP_INLINE_VISIBILITY explicit __nested(const _Tp& __t) : _Tp(__t) {}
+};
+
+#ifndef _LIBCPP_NO_EXCEPTIONS
+template <class _Tp, class _Up, bool>
+struct __throw_with_nested;
+
+template <class _Tp, class _Up>
+struct __throw_with_nested<_Tp, _Up, true> {
+    _LIBCPP_NORETURN static inline _LIBCPP_INLINE_VISIBILITY void
+    __do_throw(_Tp&& __t)
+    {
+        throw __nested<_Up>(static_cast<_Tp&&>(__t));
+    }
+};
+
+template <class _Tp, class _Up>
+struct __throw_with_nested<_Tp, _Up, false> {
+    _LIBCPP_NORETURN static inline _LIBCPP_INLINE_VISIBILITY void
+#ifndef _LIBCPP_CXX03_LANG
+    __do_throw(_Tp&& __t)
+#else
+    __do_throw (_Tp& __t)
+#endif // _LIBCPP_CXX03_LANG
+    {
+        throw static_cast<_Tp&&>(__t);
+    }
+};
+#endif
+
+template <class _Tp>
+_LIBCPP_NORETURN
+void
+throw_with_nested(_Tp&& __t)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    typedef typename decay<_Tp>::type _Up;
+    static_assert( is_copy_constructible<_Up>::value, "type thrown must be CopyConstructible");
+    __throw_with_nested<_Tp, _Up,
+        is_class<_Up>::value &&
+        !is_base_of<nested_exception, _Up>::value &&
+        !__libcpp_is_final<_Up>::value>::
+            __do_throw(static_cast<_Tp&&>(__t));
+#else
+    ((void)__t);
+    // FIXME: Make this abort
+#endif
+}
+
+template <class _From, class _To>
+struct __can_dynamic_cast : public _LIBCPP_BOOL_CONSTANT(
+              is_polymorphic<_From>::value &&
+                 (!is_base_of<_To, _From>::value ||
+                   is_convertible<const _From*, const _To*>::value)) {};
+
+template <class _Ep>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+rethrow_if_nested(const _Ep& __e,
+                  typename enable_if< __can_dynamic_cast<_Ep, nested_exception>::value>::type* = 0)
+{
+    const nested_exception* __nep = dynamic_cast<const nested_exception*>(_VSTD::addressof(__e));
+    if (__nep)
+        __nep->rethrow_nested();
+}
+
+template <class _Ep>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+rethrow_if_nested(const _Ep&,
+                  typename enable_if<!__can_dynamic_cast<_Ep, nested_exception>::value>::type* = 0)
+{
+}
+
+}  // std
+
+#endif // _LIBCPP_EXCEPTION
diff --git a/contrib/libs/cxxsupp/libcxx/include/execution b/contrib/libs/cxxsupp/libcxx/include/execution
new file mode 100644
index 00000000000..5d06f769b96
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/execution
@@ -0,0 +1,19 @@
+// -*- C++ -*-
+//===------------------------- execution ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXECUTION
+#define _LIBCPP_EXECUTION
+
+#include <__config>
+
+#if defined(_LIBCPP_HAS_PARALLEL_ALGORITHMS) && _LIBCPP_STD_VER >= 17
+//#   include <__pstl_execution>
+#endif
+
+#endif // _LIBCPP_EXECUTION
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/__config b/contrib/libs/cxxsupp/libcxx/include/experimental/__config
new file mode 100644
index 00000000000..f85426d050d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/__config
@@ -0,0 +1,75 @@
+// -*- C++ -*-
+//===--------------------------- __config ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_CONFIG
+#define _LIBCPP_EXPERIMENTAL_CONFIG
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL namespace std { namespace experimental {
+#define _LIBCPP_END_NAMESPACE_EXPERIMENTAL  } }
+#define _VSTD_EXPERIMENTAL std::experimental
+
+#define _LIBCPP_BEGIN_NAMESPACE_LFTS _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v1 {
+#define _LIBCPP_END_NAMESPACE_LFTS  } } }
+#define _VSTD_LFTS _VSTD_EXPERIMENTAL::fundamentals_v1
+
+#define _LIBCPP_BEGIN_NAMESPACE_LFTS_V2 _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace fundamentals_v2 {
+#define _LIBCPP_END_NAMESPACE_LFTS_V2  } } }
+#define _VSTD_LFTS_V2 _VSTD_EXPERIMENTAL::fundamentals_v2
+
+#define _LIBCPP_BEGIN_NAMESPACE_LFTS_PMR _LIBCPP_BEGIN_NAMESPACE_LFTS namespace pmr {
+#define _LIBCPP_END_NAMESPACE_LFTS_PMR _LIBCPP_END_NAMESPACE_LFTS }
+#define _VSTD_LFTS_PMR _VSTD_LFTS::pmr
+
+#if defined(_LIBCPP_NO_EXPERIMENTAL_DEPRECATION_WARNING_FILESYSTEM)
+#   define _LIBCPP_DEPRECATED_EXPERIMENTAL_FILESYSTEM /* nothing */
+#else
+#   define _LIBCPP_DEPRECATED_EXPERIMENTAL_FILESYSTEM __attribute__((deprecated("std::experimental::filesystem has now been deprecated in favor of C++17's std::filesystem. Please stop using it and start using std::filesystem. This experimental version will be removed in LLVM 11. You can remove this warning by defining the _LIBCPP_NO_EXPERIMENTAL_DEPRECATION_WARNING_FILESYSTEM macro.")))
+#endif
+
+#define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_FILESYSTEM \
+    _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL namespace filesystem _LIBCPP_DEPRECATED_EXPERIMENTAL_FILESYSTEM { \
+    inline namespace v1 {
+
+#define _LIBCPP_END_NAMESPACE_EXPERIMENTAL_FILESYSTEM \
+    } } _LIBCPP_END_NAMESPACE_EXPERIMENTAL
+
+#define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_COROUTINES \
+  _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace coroutines_v1 {
+
+#define _LIBCPP_END_NAMESPACE_EXPERIMENTAL_COROUTINES \
+  } _LIBCPP_END_NAMESPACE_EXPERIMENTAL
+
+#define _VSTD_CORO _VSTD_EXPERIMENTAL::coroutines_v1
+
+#define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_SIMD \
+    _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL inline namespace parallelism_v2 {
+
+#define _LIBCPP_END_NAMESPACE_EXPERIMENTAL_SIMD \
+    } _LIBCPP_END_NAMESPACE_EXPERIMENTAL
+
+#define _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_SIMD_ABI \
+    _LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_SIMD namespace simd_abi {
+
+#define _LIBCPP_END_NAMESPACE_EXPERIMENTAL_SIMD_ABI \
+    } _LIBCPP_END_NAMESPACE_EXPERIMENTAL_SIMD
+
+// TODO: support more targets
+#if defined(__AVX__)
+#define _LIBCPP_NATIVE_SIMD_WIDTH_IN_BYTES 32
+#else
+#define _LIBCPP_NATIVE_SIMD_WIDTH_IN_BYTES 16
+#endif
+
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/__memory b/contrib/libs/cxxsupp/libcxx/include/experimental/__memory
new file mode 100644
index 00000000000..b38b664b339
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/__memory
@@ -0,0 +1,114 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL___MEMORY
+#define _LIBCPP_EXPERIMENTAL___MEMORY
+
+#include <__memory/allocator_arg_t.h>
+#include <__memory/uses_allocator.h>
+#include <experimental/__config>
+#include <experimental/utility> // for erased_type
+#include <__functional_base>
+#include <type_traits>
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS
+
+template <
+    class _Tp, class _Alloc
+  , bool = uses_allocator<_Tp, _Alloc>::value
+  , bool = __has_allocator_type<_Tp>::value
+  >
+struct __lfts_uses_allocator : public false_type {};
+
+template <class _Tp, class _Alloc>
+struct __lfts_uses_allocator<_Tp, _Alloc, false, false> : public false_type {};
+
+template <class _Tp, class _Alloc, bool HasAlloc>
+struct __lfts_uses_allocator<_Tp, _Alloc, true, HasAlloc> : public true_type {};
+
+template <class _Tp, class _Alloc>
+struct __lfts_uses_allocator<_Tp, _Alloc, false, true>
+  : public integral_constant<bool
+    , is_convertible<_Alloc, typename _Tp::allocator_type>::value
+      || is_same<erased_type, typename _Tp::allocator_type>::value
+    >
+{};
+
+template <bool _UsesAlloc, class _Tp, class _Alloc, class ..._Args>
+struct __lfts_uses_alloc_ctor_imp
+{
+    static const int value = 0;
+};
+
+template <class _Tp, class _Alloc, class ..._Args>
+struct __lfts_uses_alloc_ctor_imp<true, _Tp, _Alloc, _Args...>
+{
+    static const bool __ic_first
+        = is_constructible<_Tp, allocator_arg_t, _Alloc, _Args...>::value;
+
+    static const bool __ic_second =
+        conditional<
+            __ic_first,
+            false_type,
+            is_constructible<_Tp, _Args..., _Alloc>
+        >::type::value;
+
+    static_assert(__ic_first || __ic_second,
+                  "Request for uses allocator construction is ill-formed");
+
+    static const int value = __ic_first ? 1 : 2;
+};
+
+template <class _Tp, class _Alloc, class ..._Args>
+struct __lfts_uses_alloc_ctor
+  : integral_constant<int,
+        __lfts_uses_alloc_ctor_imp<
+            __lfts_uses_allocator<_Tp, _Alloc>::value
+          , _Tp, _Alloc, _Args...
+        >::value
+    >
+{};
+
+template <class _Tp, class _Allocator, class... _Args>
+inline _LIBCPP_INLINE_VISIBILITY
+void __user_alloc_construct_impl (integral_constant<int, 0>, _Tp *__storage, const _Allocator &, _Args &&... __args )
+{
+    new (__storage) _Tp (_VSTD::forward<_Args>(__args)...);
+}
+
+// FIXME: This should have a version which takes a non-const alloc.
+template <class _Tp, class _Allocator, class... _Args>
+inline _LIBCPP_INLINE_VISIBILITY
+void __user_alloc_construct_impl (integral_constant<int, 1>, _Tp *__storage, const _Allocator &__a, _Args &&... __args )
+{
+    new (__storage) _Tp (allocator_arg, __a, _VSTD::forward<_Args>(__args)...);
+}
+
+// FIXME: This should have a version which takes a non-const alloc.
+template <class _Tp, class _Allocator, class... _Args>
+inline _LIBCPP_INLINE_VISIBILITY
+void __user_alloc_construct_impl (integral_constant<int, 2>, _Tp *__storage, const _Allocator &__a, _Args &&... __args )
+{
+    new (__storage) _Tp (_VSTD::forward<_Args>(__args)..., __a);
+}
+
+template <class _Tp, class _Alloc, class ..._Args>
+inline _LIBCPP_INLINE_VISIBILITY
+void __lfts_user_alloc_construct(
+    _Tp * __store, const _Alloc & __a, _Args &&... __args)
+{
+    ::std::experimental::fundamentals_v1::__user_alloc_construct_impl(
+        typename __lfts_uses_alloc_ctor<_Tp, _Alloc, _Args...>::type()
+       , __store, __a, _VSTD::forward<_Args>(__args)...
+       );
+}
+
+_LIBCPP_END_NAMESPACE_LFTS
+
+#endif /* _LIBCPP_EXPERIMENTAL___MEMORY */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/algorithm b/contrib/libs/cxxsupp/libcxx/include/experimental/algorithm
new file mode 100644
index 00000000000..79572ff51f8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/algorithm
@@ -0,0 +1,53 @@
+// -*- C++ -*-
+//===-------------------------- algorithm ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_ALGORITHM
+#define _LIBCPP_EXPERIMENTAL_ALGORITHM
+
+/*
+   experimental/algorithm synopsis
+
+#include <algorithm>
+
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+
+template <class ForwardIterator, class Searcher>
+ForwardIterator search(ForwardIterator first, ForwardIterator last,
+                       const Searcher &searcher);
+
+// sample removed because it's now part of C++17
+
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+*/
+
+#include <experimental/__config>
+#include <algorithm>
+#include <type_traits>
+
+#include <__debug>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS
+
+template <class _ForwardIterator, class _Searcher>
+_LIBCPP_INLINE_VISIBILITY
+_ForwardIterator search(_ForwardIterator __f, _ForwardIterator __l, const _Searcher &__s)
+{ return __s(__f, __l).first; }
+
+_LIBCPP_END_NAMESPACE_LFTS
+
+#endif /* _LIBCPP_EXPERIMENTAL_ALGORITHM */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/coroutine b/contrib/libs/cxxsupp/libcxx/include/experimental/coroutine
new file mode 100644
index 00000000000..54ec74b9f98
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/coroutine
@@ -0,0 +1,334 @@
+// -*- C++ -*-
+//===----------------------------- coroutine -----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_COROUTINE
+#define _LIBCPP_EXPERIMENTAL_COROUTINE
+
+/**
+    experimental/coroutine synopsis
+
+// C++next
+
+namespace std {
+namespace experimental {
+inline namespace coroutines_v1 {
+
+  // 18.11.1 coroutine traits
+template <typename R, typename... ArgTypes>
+class coroutine_traits;
+// 18.11.2 coroutine handle
+template <typename Promise = void>
+class coroutine_handle;
+// 18.11.2.7 comparison operators:
+bool operator==(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
+bool operator!=(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
+bool operator<(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
+bool operator<=(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
+bool operator>=(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
+bool operator>(coroutine_handle<> x, coroutine_handle<> y) _NOEXCEPT;
+// 18.11.3 trivial awaitables
+struct suspend_never;
+struct suspend_always;
+// 18.11.2.8 hash support:
+template <class T> struct hash;
+template <class P> struct hash<coroutine_handle<P>>;
+
+} // namespace coroutines_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <new>
+#include <type_traits>
+#include <functional>
+#include <memory> // for hash<T*>
+#include <cstddef>
+#include <__debug>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_HAS_NO_COROUTINES
+# if defined(_LIBCPP_WARNING)
+    _LIBCPP_WARNING("<experimental/coroutine> cannot be used with this compiler")
+# else
+#   warning <experimental/coroutine> cannot be used with this compiler
+# endif
+#endif
+
+#ifndef _LIBCPP_HAS_NO_COROUTINES
+
+_LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_COROUTINES
+
+template <class _Tp, class = void>
+struct __coroutine_traits_sfinae {};
+
+template <class _Tp>
+struct __coroutine_traits_sfinae<
+    _Tp, typename __void_t<typename _Tp::promise_type>::type>
+{
+  using promise_type = typename _Tp::promise_type;
+};
+
+template <typename _Ret, typename... _Args>
+struct coroutine_traits
+    : public __coroutine_traits_sfinae<_Ret>
+{
+};
+
+template <typename _Promise = void>
+class _LIBCPP_TEMPLATE_VIS coroutine_handle;
+
+template <>
+class _LIBCPP_TEMPLATE_VIS coroutine_handle<void> {
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR coroutine_handle() _NOEXCEPT : __handle_(nullptr) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR coroutine_handle(nullptr_t) _NOEXCEPT : __handle_(nullptr) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    coroutine_handle& operator=(nullptr_t) _NOEXCEPT {
+        __handle_ = nullptr;
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR void* address() const _NOEXCEPT { return __handle_; }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR explicit operator bool() const _NOEXCEPT { return __handle_; }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator()() { resume(); }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void resume() {
+      _LIBCPP_ASSERT(__is_suspended(),
+                     "resume() can only be called on suspended coroutines");
+      _LIBCPP_ASSERT(!done(),
+                "resume() has undefined behavior when the coroutine is done");
+      __builtin_coro_resume(__handle_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void destroy() {
+      _LIBCPP_ASSERT(__is_suspended(),
+                     "destroy() can only be called on suspended coroutines");
+      __builtin_coro_destroy(__handle_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool done() const {
+      _LIBCPP_ASSERT(__is_suspended(),
+                     "done() can only be called on suspended coroutines");
+      return __builtin_coro_done(__handle_);
+    }
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    static coroutine_handle from_address(void* __addr) _NOEXCEPT {
+        coroutine_handle __tmp;
+        __tmp.__handle_ = __addr;
+        return __tmp;
+    }
+
+    // FIXME: Should from_address(nullptr) be allowed?
+    _LIBCPP_INLINE_VISIBILITY
+    static coroutine_handle from_address(nullptr_t) _NOEXCEPT {
+      return coroutine_handle(nullptr);
+    }
+
+    template <class _Tp, bool _CallIsValid = false>
+    static coroutine_handle from_address(_Tp*) {
+      static_assert(_CallIsValid,
+       "coroutine_handle<void>::from_address cannot be called with "
+        "non-void pointers");
+    }
+
+private:
+  bool __is_suspended() const _NOEXCEPT  {
+    // FIXME actually implement a check for if the coro is suspended.
+    return __handle_;
+  }
+
+  template <class _PromiseT> friend class coroutine_handle;
+  void* __handle_;
+};
+
+// 18.11.2.7 comparison operators:
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator==(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
+    return __x.address() == __y.address();
+}
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator!=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
+    return !(__x == __y);
+}
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator<(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
+    return less<void*>()(__x.address(), __y.address());
+}
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator>(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
+    return __y < __x;
+}
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator<=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
+    return !(__x > __y);
+}
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator>=(coroutine_handle<> __x, coroutine_handle<> __y) _NOEXCEPT {
+    return !(__x < __y);
+}
+
+template <typename _Promise>
+class _LIBCPP_TEMPLATE_VIS coroutine_handle : public coroutine_handle<> {
+    using _Base = coroutine_handle<>;
+public:
+#ifndef _LIBCPP_CXX03_LANG
+    // 18.11.2.1 construct/reset
+    using coroutine_handle<>::coroutine_handle;
+#else
+    _LIBCPP_INLINE_VISIBILITY coroutine_handle() _NOEXCEPT : _Base() {}
+    _LIBCPP_INLINE_VISIBILITY coroutine_handle(nullptr_t) _NOEXCEPT : _Base(nullptr) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    coroutine_handle& operator=(nullptr_t) _NOEXCEPT {
+        _Base::operator=(nullptr);
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Promise& promise() const {
+        return *static_cast<_Promise*>(
+            __builtin_coro_promise(this->__handle_, _LIBCPP_ALIGNOF(_Promise), false));
+    }
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    static coroutine_handle from_address(void* __addr) _NOEXCEPT {
+        coroutine_handle __tmp;
+        __tmp.__handle_ = __addr;
+        return __tmp;
+    }
+
+    // NOTE: this overload isn't required by the standard but is needed so
+    // the deleted _Promise* overload doesn't make from_address(nullptr)
+    // ambiguous.
+    // FIXME: should from_address work with nullptr?
+    _LIBCPP_INLINE_VISIBILITY
+    static coroutine_handle from_address(nullptr_t) _NOEXCEPT {
+      return coroutine_handle(nullptr);
+    }
+
+    template <class _Tp, bool _CallIsValid = false>
+    static coroutine_handle from_address(_Tp*) {
+      static_assert(_CallIsValid,
+       "coroutine_handle<promise_type>::from_address cannot be called with "
+        "non-void pointers");
+    }
+
+    template <bool _CallIsValid = false>
+    static coroutine_handle from_address(_Promise*) {
+      static_assert(_CallIsValid,
+       "coroutine_handle<promise_type>::from_address cannot be used with "
+        "pointers to the coroutine's promise type; use 'from_promise' instead");
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    static coroutine_handle from_promise(_Promise& __promise) _NOEXCEPT {
+        typedef typename remove_cv<_Promise>::type _RawPromise;
+        coroutine_handle __tmp;
+        __tmp.__handle_ = __builtin_coro_promise(
+            _VSTD::addressof(const_cast<_RawPromise&>(__promise)),
+             _LIBCPP_ALIGNOF(_Promise), true);
+        return __tmp;
+    }
+};
+
+#if __has_builtin(__builtin_coro_noop)
+struct noop_coroutine_promise {};
+
+template <>
+class _LIBCPP_TEMPLATE_VIS coroutine_handle<noop_coroutine_promise>
+    : public coroutine_handle<> {
+  using _Base = coroutine_handle<>;
+  using _Promise = noop_coroutine_promise;
+public:
+
+  _LIBCPP_INLINE_VISIBILITY
+  _Promise& promise() const {
+    return *static_cast<_Promise*>(
+      __builtin_coro_promise(this->__handle_, _LIBCPP_ALIGNOF(_Promise), false));
+  }
+
+  _LIBCPP_CONSTEXPR explicit operator bool() const _NOEXCEPT { return true; }
+  _LIBCPP_CONSTEXPR bool done() const _NOEXCEPT { return false; }
+
+  _LIBCPP_CONSTEXPR_AFTER_CXX17 void operator()() const _NOEXCEPT {}
+  _LIBCPP_CONSTEXPR_AFTER_CXX17 void resume() const _NOEXCEPT {}
+  _LIBCPP_CONSTEXPR_AFTER_CXX17 void destroy() const _NOEXCEPT {}
+
+private:
+  _LIBCPP_INLINE_VISIBILITY
+  friend coroutine_handle<noop_coroutine_promise> noop_coroutine() _NOEXCEPT;
+
+  _LIBCPP_INLINE_VISIBILITY coroutine_handle() _NOEXCEPT {
+    this->__handle_ = __builtin_coro_noop();
+  }
+};
+
+using noop_coroutine_handle = coroutine_handle<noop_coroutine_promise>;
+
+inline _LIBCPP_INLINE_VISIBILITY
+noop_coroutine_handle noop_coroutine() _NOEXCEPT {
+  return noop_coroutine_handle();
+}
+#endif // __has_builtin(__builtin_coro_noop)
+
+struct suspend_never {
+  _LIBCPP_INLINE_VISIBILITY
+  bool await_ready() const _NOEXCEPT { return true; }
+  _LIBCPP_INLINE_VISIBILITY
+  void await_suspend(coroutine_handle<>) const _NOEXCEPT {}
+  _LIBCPP_INLINE_VISIBILITY
+  void await_resume() const _NOEXCEPT {}
+};
+
+struct suspend_always {
+  _LIBCPP_INLINE_VISIBILITY
+  bool await_ready() const _NOEXCEPT { return false; }
+  _LIBCPP_INLINE_VISIBILITY
+  void await_suspend(coroutine_handle<>) const _NOEXCEPT {}
+  _LIBCPP_INLINE_VISIBILITY
+  void await_resume() const _NOEXCEPT {}
+};
+
+_LIBCPP_END_NAMESPACE_EXPERIMENTAL_COROUTINES
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+struct hash<_VSTD_CORO::coroutine_handle<_Tp> > {
+    using __arg_type = _VSTD_CORO::coroutine_handle<_Tp>;
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(__arg_type const& __v) const _NOEXCEPT
+    {return hash<void*>()(__v.address());}
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_COROUTINES)
+
+#endif /* _LIBCPP_EXPERIMENTAL_COROUTINE */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/deque b/contrib/libs/cxxsupp/libcxx/include/experimental/deque
new file mode 100644
index 00000000000..73c2787c7a0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/deque
@@ -0,0 +1,46 @@
+// -*- C++ -*-
+//===--------------------------- deque ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_DEQUE
+#define _LIBCPP_EXPERIMENTAL_DEQUE
+/*
+    experimental/deque synopsis
+
+// C++1z
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+namespace pmr {
+
+  template <class T>
+  using deque = std::deque<T,polymorphic_allocator<T>>;
+
+} // namespace pmr
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <deque>
+#include <experimental/memory_resource>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+template <class _ValueT>
+using deque = _VSTD::deque<_ValueT, polymorphic_allocator<_ValueT>>;
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR
+
+#endif /* _LIBCPP_EXPERIMENTAL_DEQUE */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/filesystem b/contrib/libs/cxxsupp/libcxx/include/experimental/filesystem
new file mode 100644
index 00000000000..d2e6237df34
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/filesystem
@@ -0,0 +1,256 @@
+// -*- C++ -*-
+//===--------------------------- filesystem -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP_EXPERIMENTAL_FILESYSTEM
+#define _LIBCPP_EXPERIMENTAL_FILESYSTEM
+/*
+    filesystem synopsis
+
+    namespace std { namespace experimental { namespace filesystem { inline namespace v1 {
+
+    class path;
+
+    void swap(path& lhs, path& rhs) noexcept;
+    size_t hash_value(const path& p) noexcept;
+
+    bool operator==(const path& lhs, const path& rhs) noexcept;
+    bool operator!=(const path& lhs, const path& rhs) noexcept;
+    bool operator< (const path& lhs, const path& rhs) noexcept;
+    bool operator<=(const path& lhs, const path& rhs) noexcept;
+    bool operator> (const path& lhs, const path& rhs) noexcept;
+    bool operator>=(const path& lhs, const path& rhs) noexcept;
+
+    path operator/ (const path& lhs, const path& rhs);
+
+    // fs.path.io operators are friends of path.
+    template <class charT, class traits>
+    friend basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os, const path& p);
+
+    template <class charT, class traits>
+    friend basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is, path& p);
+
+    template <class Source>
+      path u8path(const Source& source);
+    template <class InputIterator>
+      path u8path(InputIterator first, InputIterator last);
+
+    class filesystem_error;
+    class directory_entry;
+
+    class directory_iterator;
+
+    // enable directory_iterator range-based for statements
+    directory_iterator begin(directory_iterator iter) noexcept;
+    directory_iterator end(const directory_iterator&) noexcept;
+
+    class recursive_directory_iterator;
+
+    // enable recursive_directory_iterator range-based for statements
+    recursive_directory_iterator begin(recursive_directory_iterator iter) noexcept;
+    recursive_directory_iterator end(const recursive_directory_iterator&) noexcept;
+
+    class file_status;
+
+    struct space_info
+    {
+      uintmax_t capacity;
+      uintmax_t free;
+      uintmax_t available;
+    };
+
+    enum class file_type;
+    enum class perms;
+    enum class perm_options;
+    enum class copy_options;
+    enum class directory_options;
+
+    typedef chrono::time_point<trivial-clock>  file_time_type;
+
+    // operational functions
+
+    path absolute(const path& p);
+    path absolute(const path& p, error_code &ec);
+
+    path canonical(const path& p);
+    path canonical(const path& p, error_code& ec);
+
+    void copy(const path& from, const path& to);
+    void copy(const path& from, const path& to, error_code& ec);
+    void copy(const path& from, const path& to, copy_options options);
+    void copy(const path& from, const path& to, copy_options options,
+                   error_code& ec);
+
+    bool copy_file(const path& from, const path& to);
+    bool copy_file(const path& from, const path& to, error_code& ec);
+    bool copy_file(const path& from, const path& to, copy_options option);
+    bool copy_file(const path& from, const path& to, copy_options option,
+                           error_code& ec);
+
+    void copy_symlink(const path& existing_symlink, const path& new_symlink);
+    void copy_symlink(const path& existing_symlink, const path& new_symlink,
+                              error_code& ec) noexcept;
+
+    bool create_directories(const path& p);
+    bool create_directories(const path& p, error_code& ec);
+
+    bool create_directory(const path& p);
+    bool create_directory(const path& p, error_code& ec) noexcept;
+
+    bool create_directory(const path& p, const path& attributes);
+    bool create_directory(const path& p, const path& attributes,
+                                  error_code& ec) noexcept;
+
+    void create_directory_symlink(const path& to, const path& new_symlink);
+    void create_directory_symlink(const path& to, const path& new_symlink,
+                                          error_code& ec) noexcept;
+
+    void create_hard_link(const path& to, const path& new_hard_link);
+    void create_hard_link(const path& to, const path& new_hard_link,
+                                  error_code& ec) noexcept;
+
+    void create_symlink(const path& to, const path& new_symlink);
+    void create_symlink(const path& to, const path& new_symlink,
+                                error_code& ec) noexcept;
+
+    path current_path();
+    path current_path(error_code& ec);
+    void current_path(const path& p);
+    void current_path(const path& p, error_code& ec) noexcept;
+
+    bool exists(file_status s) noexcept;
+    bool exists(const path& p);
+    bool exists(const path& p, error_code& ec) noexcept;
+
+    bool equivalent(const path& p1, const path& p2);
+    bool equivalent(const path& p1, const path& p2, error_code& ec) noexcept;
+
+    uintmax_t    file_size(const path& p);
+    uintmax_t    file_size(const path& p, error_code& ec) noexcept;
+
+    uintmax_t    hard_link_count(const path& p);
+    uintmax_t    hard_link_count(const path& p, error_code& ec) noexcept;
+
+    bool is_block_file(file_status s) noexcept;
+    bool is_block_file(const path& p);
+    bool is_block_file(const path& p, error_code& ec) noexcept;
+
+    bool is_character_file(file_status s) noexcept;
+    bool is_character_file(const path& p);
+    bool is_character_file(const path& p, error_code& ec) noexcept;
+
+    bool is_directory(file_status s) noexcept;
+    bool is_directory(const path& p);
+    bool is_directory(const path& p, error_code& ec) noexcept;
+
+    bool is_empty(const path& p);
+    bool is_empty(const path& p, error_code& ec) noexcept;
+
+    bool is_fifo(file_status s) noexcept;
+    bool is_fifo(const path& p);
+    bool is_fifo(const path& p, error_code& ec) noexcept;
+
+    bool is_other(file_status s) noexcept;
+    bool is_other(const path& p);
+    bool is_other(const path& p, error_code& ec) noexcept;
+
+    bool is_regular_file(file_status s) noexcept;
+    bool is_regular_file(const path& p);
+    bool is_regular_file(const path& p, error_code& ec) noexcept;
+
+    bool is_socket(file_status s) noexcept;
+    bool is_socket(const path& p);
+    bool is_socket(const path& p, error_code& ec) noexcept;
+
+    bool is_symlink(file_status s) noexcept;
+    bool is_symlink(const path& p);
+    bool is_symlink(const path& p, error_code& ec) noexcept;
+
+    file_time_type  last_write_time(const path& p);
+    file_time_type  last_write_time(const path& p, error_code& ec) noexcept;
+    void last_write_time(const path& p, file_time_type new_time);
+    void last_write_time(const path& p, file_time_type new_time,
+                                 error_code& ec) noexcept;
+
+    void permissions(const path& p, perms prms,
+                     perm_options opts=perm_options::replace);
+    void permissions(const path& p, perms prms, error_code& ec) noexcept;
+    void permissions(const path& p, perms prms, perm_options opts,
+                     error_code& ec);
+
+    path proximate(const path& p, error_code& ec);
+    path proximate(const path& p, const path& base = current_path());
+    path proximate(const path& p, const path& base, error_code &ec);
+
+    path read_symlink(const path& p);
+    path read_symlink(const path& p, error_code& ec);
+
+    path relative(const path& p, error_code& ec);
+    path relative(const path& p, const path& base=current_path());
+    path relative(const path& p, const path& base, error_code& ec);
+
+    bool remove(const path& p);
+    bool remove(const path& p, error_code& ec) noexcept;
+
+    uintmax_t    remove_all(const path& p);
+    uintmax_t    remove_all(const path& p, error_code& ec);
+
+    void rename(const path& from, const path& to);
+    void rename(const path& from, const path& to, error_code& ec) noexcept;
+
+    void resize_file(const path& p, uintmax_t size);
+    void resize_file(const path& p, uintmax_t size, error_code& ec) noexcept;
+
+    space_info   space(const path& p);
+    space_info   space(const path& p, error_code& ec) noexcept;
+
+    file_status  status(const path& p);
+    file_status  status(const path& p, error_code& ec) noexcept;
+
+    bool status_known(file_status s) noexcept;
+
+    file_status  symlink_status(const path& p);
+    file_status  symlink_status(const path& p, error_code& ec) noexcept;
+
+    path temp_directory_path();
+    path temp_directory_path(error_code& ec);
+
+    path weakly_canonical(path const& p);
+    path weakly_canonical(path const& p, error_code& ec);
+
+
+} } } }  // namespaces std::experimental::filesystem::v1
+
+*/
+
+#include <experimental/__config>
+#include <filesystem>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#ifndef _LIBCPP_CXX03_LANG
+
+#define __cpp_lib_experimental_filesystem 201406
+
+_LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_FILESYSTEM
+
+using namespace _VSTD_FS;
+
+_LIBCPP_END_NAMESPACE_EXPERIMENTAL_FILESYSTEM
+
+#endif // !_LIBCPP_CXX03_LANG
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_EXPERIMENTAL_FILESYSTEM
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/forward_list b/contrib/libs/cxxsupp/libcxx/include/experimental/forward_list
new file mode 100644
index 00000000000..93f6debe9cb
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/forward_list
@@ -0,0 +1,46 @@
+// -*- C++ -*-
+//===--------------------------- forward_list -----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_FORWARD_LIST
+#define _LIBCPP_EXPERIMENTAL_FORWARD_LIST
+/*
+    experimental/forward_list synopsis
+
+// C++1z
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+namespace pmr {
+
+  template <class T>
+  using forward_list = std::forward_list<T,polymorphic_allocator<T>>;
+
+} // namespace pmr
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <forward_list>
+#include <experimental/memory_resource>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+template <class _ValueT>
+using forward_list = _VSTD::forward_list<_ValueT, polymorphic_allocator<_ValueT>>;
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR
+
+#endif /* _LIBCPP_EXPERIMENTAL_FORWARD_LIST */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/functional b/contrib/libs/cxxsupp/libcxx/include/experimental/functional
new file mode 100644
index 00000000000..e3220e16cae
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/functional
@@ -0,0 +1,459 @@
+// -*- C++ -*-
+//===-------------------------- functional --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_FUNCTIONAL
+#define _LIBCPP_EXPERIMENTAL_FUNCTIONAL
+
+/*
+   experimental/functional synopsis
+
+#include <algorithm>
+
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+
+    // See C++14 20.9.9, Function object binders
+    template <class T> constexpr bool is_bind_expression_v
+      = is_bind_expression<T>::value;
+    template <class T> constexpr int is_placeholder_v
+      = is_placeholder<T>::value;
+
+    // 4.2, Class template function
+    template<class> class function; // undefined
+    template<class R, class... ArgTypes> class function<R(ArgTypes...)>;
+
+    template<class R, class... ArgTypes>
+    void swap(function<R(ArgTypes...)>&, function<R(ArgTypes...)>&);
+
+    template<class R, class... ArgTypes>
+    bool operator==(const function<R(ArgTypes...)>&, nullptr_t) noexcept;
+    template<class R, class... ArgTypes>
+    bool operator==(nullptr_t, const function<R(ArgTypes...)>&) noexcept;
+    template<class R, class... ArgTypes>
+    bool operator!=(const function<R(ArgTypes...)>&, nullptr_t) noexcept;
+    template<class R, class... ArgTypes>
+    bool operator!=(nullptr_t, const function<R(ArgTypes...)>&) noexcept;
+
+    // 4.3, Searchers
+    template<class ForwardIterator, class BinaryPredicate = equal_to<>>
+      class default_searcher;
+
+    template<class RandomAccessIterator,
+             class Hash = hash<typename iterator_traits<RandomAccessIterator>::value_type>,
+             class BinaryPredicate = equal_to<>>
+      class boyer_moore_searcher;
+
+    template<class RandomAccessIterator,
+             class Hash = hash<typename iterator_traits<RandomAccessIterator>::value_type>,
+             class BinaryPredicate = equal_to<>>
+      class boyer_moore_horspool_searcher;
+
+    template<class ForwardIterator, class BinaryPredicate = equal_to<>>
+    default_searcher<ForwardIterator, BinaryPredicate>
+    make_default_searcher(ForwardIterator pat_first, ForwardIterator pat_last,
+                          BinaryPredicate pred = BinaryPredicate());
+
+    template<class RandomAccessIterator,
+             class Hash = hash<typename iterator_traits<RandomAccessIterator>::value_type>,
+             class BinaryPredicate = equal_to<>>
+    boyer_moore_searcher<RandomAccessIterator, Hash, BinaryPredicate>
+    make_boyer_moore_searcher(
+        RandomAccessIterator pat_first, RandomAccessIterator pat_last,
+        Hash hf = Hash(), BinaryPredicate pred = BinaryPredicate());
+
+    template<class RandomAccessIterator,
+             class Hash = hash<typename iterator_traits<RandomAccessIterator>::value_type>,
+             class BinaryPredicate = equal_to<>>
+    boyer_moore_horspool_searcher<RandomAccessIterator, Hash, BinaryPredicate>
+    make_boyer_moore_horspool_searcher(
+        RandomAccessIterator pat_first, RandomAccessIterator pat_last,
+        Hash hf = Hash(), BinaryPredicate pred = BinaryPredicate());
+
+  } // namespace fundamentals_v1
+  } // namespace experimental
+
+  template<class R, class... ArgTypes, class Alloc>
+  struct uses_allocator<experimental::function<R(ArgTypes...)>, Alloc>;
+
+} // namespace std
+
+*/
+
+#include <__memory/uses_allocator.h>
+#include <experimental/__config>
+#include <functional>
+#include <algorithm>
+#include <type_traits>
+#include <vector>
+#include <array>
+#include <unordered_map>
+
+#include <__debug>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS
+
+#if _LIBCPP_STD_VER > 11
+// default searcher
+template<class _ForwardIterator, class _BinaryPredicate = equal_to<>>
+class _LIBCPP_TEMPLATE_VIS default_searcher {
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    default_searcher(_ForwardIterator __f, _ForwardIterator __l,
+                       _BinaryPredicate __p = _BinaryPredicate())
+        : __first_(__f), __last_(__l), __pred_(__p) {}
+
+    template <typename _ForwardIterator2>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<_ForwardIterator2, _ForwardIterator2>
+    operator () (_ForwardIterator2 __f, _ForwardIterator2 __l) const
+    {
+        return _VSTD::__search(__f, __l, __first_, __last_, __pred_,
+            typename iterator_traits<_ForwardIterator>::iterator_category(),
+            typename iterator_traits<_ForwardIterator2>::iterator_category());
+    }
+
+private:
+    _ForwardIterator __first_;
+    _ForwardIterator __last_;
+    _BinaryPredicate __pred_;
+    };
+
+template<class _ForwardIterator, class _BinaryPredicate = equal_to<>>
+_LIBCPP_INLINE_VISIBILITY
+default_searcher<_ForwardIterator, _BinaryPredicate>
+make_default_searcher( _ForwardIterator __f, _ForwardIterator __l, _BinaryPredicate __p = _BinaryPredicate ())
+{
+    return default_searcher<_ForwardIterator, _BinaryPredicate>(__f, __l, __p);
+}
+
+template<class _Key, class _Value, class _Hash, class _BinaryPredicate, bool /*useArray*/> class _BMSkipTable;
+
+//  General case for BM data searching; use a map
+template<class _Key, typename _Value, class _Hash, class _BinaryPredicate>
+class _BMSkipTable<_Key, _Value, _Hash, _BinaryPredicate, false> {
+public: // TODO private:
+    typedef _Value value_type;
+    typedef _Key   key_type;
+
+    const _Value __default_value_;
+    std::unordered_map<_Key, _Value, _Hash, _BinaryPredicate> __table;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    _BMSkipTable(size_t __sz, _Value __default, _Hash __hf, _BinaryPredicate __pred)
+        : __default_value_(__default), __table(__sz, __hf, __pred) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void insert(const key_type &__key, value_type __val)
+    {
+        __table [__key] = __val;    // Would skip_.insert (val) be better here?
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    value_type operator [](const key_type & __key) const
+    {
+        auto __it = __table.find (__key);
+        return __it == __table.end() ? __default_value_ : __it->second;
+    }
+};
+
+
+//  Special case small numeric values; use an array
+template<class _Key, typename _Value, class _Hash, class _BinaryPredicate>
+class _BMSkipTable<_Key, _Value, _Hash, _BinaryPredicate, true> {
+private:
+    typedef _Value value_type;
+    typedef _Key   key_type;
+
+    typedef typename make_unsigned<key_type>::type unsigned_key_type;
+    typedef std::array<value_type, numeric_limits<unsigned_key_type>::max()> skip_map;
+    skip_map __table;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    _BMSkipTable(size_t /*__sz*/, _Value __default, _Hash /*__hf*/, _BinaryPredicate /*__pred*/)
+    {
+        std::fill_n(__table.begin(), __table.size(), __default);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void insert(key_type __key, value_type __val)
+    {
+        __table[static_cast<unsigned_key_type>(__key)] = __val;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    value_type operator [](key_type __key) const
+    {
+        return __table[static_cast<unsigned_key_type>(__key)];
+    }
+};
+
+
+template <class _RandomAccessIterator1,
+          class _Hash = hash<typename iterator_traits<_RandomAccessIterator1>::value_type>,
+          class _BinaryPredicate = equal_to<>>
+class _LIBCPP_TEMPLATE_VIS boyer_moore_searcher {
+private:
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type difference_type;
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::value_type      value_type;
+    typedef _BMSkipTable<value_type, difference_type, _Hash, _BinaryPredicate,
+                    is_integral<value_type>::value && // what about enums?
+                    sizeof(value_type) == 1 &&
+                    is_same<_Hash, hash<value_type>>::value &&
+                    is_same<_BinaryPredicate, equal_to<>>::value
+            > skip_table_type;
+
+public:
+    boyer_moore_searcher(_RandomAccessIterator1 __f, _RandomAccessIterator1 __l,
+                _Hash __hf = _Hash(), _BinaryPredicate __pred = _BinaryPredicate())
+            : __first_(__f), __last_(__l), __pred_(__pred),
+              __pattern_length_(_VSTD::distance(__first_, __last_)),
+              __skip_{make_shared<skip_table_type>(__pattern_length_, -1, __hf, __pred_)},
+              __suffix_{make_shared<vector<difference_type>>(__pattern_length_ + 1)}
+        {
+    //  build the skip table
+        for ( difference_type __i = 0; __f != __l; ++__f, (void) ++__i )
+            __skip_->insert(*__f, __i);
+
+        this->__build_suffix_table ( __first_, __last_, __pred_ );
+        }
+
+    template <typename _RandomAccessIterator2>
+    pair<_RandomAccessIterator2, _RandomAccessIterator2>
+    operator ()(_RandomAccessIterator2 __f, _RandomAccessIterator2 __l) const
+    {
+        static_assert ( std::is_same<
+                typename std::__uncvref<typename std::iterator_traits<_RandomAccessIterator1>::value_type>::type,
+                typename std::__uncvref<typename std::iterator_traits<_RandomAccessIterator2>::value_type>::type
+                    >::value,
+                "Corpus and Pattern iterators must point to the same type" );
+
+        if (__f      == __l )    return make_pair(__l, __l); // empty corpus
+        if (__first_ == __last_) return make_pair(__f, __f); // empty pattern
+
+    //  If the pattern is larger than the corpus, we can't find it!
+        if ( __pattern_length_ > _VSTD::distance(__f, __l))
+            return make_pair(__l, __l);
+
+    //  Do the search
+        return this->__search(__f, __l);
+    }
+
+public: // TODO private:
+    _RandomAccessIterator1               __first_;
+    _RandomAccessIterator1               __last_;
+    _BinaryPredicate                     __pred_;
+    difference_type                      __pattern_length_;
+    shared_ptr<skip_table_type>          __skip_;
+    shared_ptr<vector<difference_type>>  __suffix_;
+
+    template <typename _RandomAccessIterator2>
+    pair<_RandomAccessIterator2, _RandomAccessIterator2>
+    __search(_RandomAccessIterator2 __f, _RandomAccessIterator2 __l) const
+    {
+        _RandomAccessIterator2 __cur = __f;
+        const _RandomAccessIterator2 __last = __l - __pattern_length_;
+        const skip_table_type &         __skip   = *__skip_.get();
+        const vector<difference_type> & __suffix = *__suffix_.get();
+
+        while (__cur <= __last)
+        {
+
+        //  Do we match right where we are?
+            difference_type __j = __pattern_length_;
+            while (__pred_(__first_ [__j-1], __cur [__j-1])) {
+                __j--;
+            //  We matched - we're done!
+                if ( __j == 0 )
+                    return make_pair(__cur, __cur + __pattern_length_);
+                }
+
+        //  Since we didn't match, figure out how far to skip forward
+            difference_type __k = __skip[__cur [ __j - 1 ]];
+            difference_type __m = __j - __k - 1;
+            if (__k < __j && __m > __suffix[ __j ])
+                __cur += __m;
+            else
+                __cur += __suffix[ __j ];
+        }
+
+        return make_pair(__l, __l);     // We didn't find anything
+    }
+
+
+    template<typename _Iterator, typename _Container>
+    void __compute_bm_prefix ( _Iterator __f, _Iterator __l, _BinaryPredicate __pred, _Container &__prefix )
+    {
+        const size_t __count = _VSTD::distance(__f, __l);
+
+        __prefix[0] = 0;
+        size_t __k = 0;
+        for ( size_t __i = 1; __i < __count; ++__i )
+        {
+            while ( __k > 0 && !__pred ( __f[__k], __f[__i] ))
+                __k = __prefix [ __k - 1 ];
+
+            if ( __pred ( __f[__k], __f[__i] ))
+                __k++;
+            __prefix [ __i ] = __k;
+        }
+    }
+
+    void __build_suffix_table(_RandomAccessIterator1 __f, _RandomAccessIterator1 __l,
+                                                    _BinaryPredicate __pred)
+    {
+        const size_t __count = _VSTD::distance(__f, __l);
+        vector<difference_type> & __suffix = *__suffix_.get();
+        if (__count > 0)
+        {
+            vector<value_type> __scratch(__count);
+
+            __compute_bm_prefix(__f, __l, __pred, __scratch);
+            for ( size_t __i = 0; __i <= __count; __i++ )
+                __suffix[__i] = __count - __scratch[__count-1];
+
+            typedef reverse_iterator<_RandomAccessIterator1> _RevIter;
+            __compute_bm_prefix(_RevIter(__l), _RevIter(__f), __pred, __scratch);
+
+            for ( size_t __i = 0; __i < __count; __i++ )
+            {
+                const size_t     __j = __count - __scratch[__i];
+                const difference_type __k = __i     - __scratch[__i] + 1;
+
+                if (__suffix[__j] > __k)
+                    __suffix[__j] = __k;
+            }
+        }
+    }
+
+};
+
+template<class _RandomAccessIterator,
+         class _Hash = hash<typename iterator_traits<_RandomAccessIterator>::value_type>,
+         class _BinaryPredicate = equal_to<>>
+_LIBCPP_INLINE_VISIBILITY
+boyer_moore_searcher<_RandomAccessIterator, _Hash, _BinaryPredicate>
+make_boyer_moore_searcher( _RandomAccessIterator __f, _RandomAccessIterator __l,
+                    _Hash __hf = _Hash(), _BinaryPredicate __p = _BinaryPredicate ())
+{
+    return boyer_moore_searcher<_RandomAccessIterator, _Hash, _BinaryPredicate>(__f, __l, __hf, __p);
+}
+
+// boyer-moore-horspool
+template <class _RandomAccessIterator1,
+          class _Hash = hash<typename iterator_traits<_RandomAccessIterator1>::value_type>,
+          class _BinaryPredicate = equal_to<>>
+class _LIBCPP_TEMPLATE_VIS boyer_moore_horspool_searcher {
+private:
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type difference_type;
+    typedef typename std::iterator_traits<_RandomAccessIterator1>::value_type      value_type;
+    typedef _BMSkipTable<value_type, difference_type, _Hash, _BinaryPredicate,
+                    is_integral<value_type>::value && // what about enums?
+                    sizeof(value_type) == 1 &&
+                    is_same<_Hash, hash<value_type>>::value &&
+                    is_same<_BinaryPredicate, equal_to<>>::value
+            > skip_table_type;
+
+public:
+    boyer_moore_horspool_searcher(_RandomAccessIterator1 __f, _RandomAccessIterator1 __l,
+                _Hash __hf = _Hash(), _BinaryPredicate __pred = _BinaryPredicate())
+            : __first_(__f), __last_(__l), __pred_(__pred),
+              __pattern_length_(_VSTD::distance(__first_, __last_)),
+              __skip_{_VSTD::make_shared<skip_table_type>(__pattern_length_, __pattern_length_, __hf, __pred_)}
+        {
+    //  build the skip table
+            if ( __f != __l )
+            {
+                __l = __l - 1;
+                for ( difference_type __i = 0; __f != __l; ++__f, (void) ++__i )
+                    __skip_->insert(*__f, __pattern_length_ - 1 - __i);
+            }
+        }
+
+    template <typename _RandomAccessIterator2>
+    pair<_RandomAccessIterator2, _RandomAccessIterator2>
+    operator ()(_RandomAccessIterator2 __f, _RandomAccessIterator2 __l) const
+    {
+        static_assert ( std::is_same<
+                typename std::__uncvref<typename std::iterator_traits<_RandomAccessIterator1>::value_type>::type,
+                typename std::__uncvref<typename std::iterator_traits<_RandomAccessIterator2>::value_type>::type
+                    >::value,
+                "Corpus and Pattern iterators must point to the same type" );
+
+        if (__f      == __l )    return make_pair(__l, __l); // empty corpus
+        if (__first_ == __last_) return make_pair(__f, __f); // empty pattern
+
+    //  If the pattern is larger than the corpus, we can't find it!
+        if ( __pattern_length_ > _VSTD::distance(__f, __l))
+            return make_pair(__l, __l);
+
+    //  Do the search
+        return this->__search(__f, __l);
+    }
+
+private:
+    _RandomAccessIterator1      __first_;
+    _RandomAccessIterator1      __last_;
+    _BinaryPredicate            __pred_;
+    difference_type             __pattern_length_;
+    shared_ptr<skip_table_type> __skip_;
+
+    template <typename _RandomAccessIterator2>
+    pair<_RandomAccessIterator2, _RandomAccessIterator2>
+    __search ( _RandomAccessIterator2 __f, _RandomAccessIterator2 __l ) const {
+        _RandomAccessIterator2 __cur = __f;
+        const _RandomAccessIterator2 __last = __l - __pattern_length_;
+        const skip_table_type & __skip = *__skip_.get();
+
+        while (__cur <= __last)
+        {
+        //  Do we match right where we are?
+            difference_type __j = __pattern_length_;
+            while (__pred_(__first_[__j-1], __cur[__j-1]))
+            {
+                __j--;
+            //  We matched - we're done!
+                if ( __j == 0 )
+                    return make_pair(__cur, __cur + __pattern_length_);
+            }
+            __cur += __skip[__cur[__pattern_length_-1]];
+        }
+
+        return make_pair(__l, __l);
+    }
+};
+
+template<class _RandomAccessIterator,
+         class _Hash = hash<typename iterator_traits<_RandomAccessIterator>::value_type>,
+         class _BinaryPredicate = equal_to<>>
+_LIBCPP_INLINE_VISIBILITY
+boyer_moore_horspool_searcher<_RandomAccessIterator, _Hash, _BinaryPredicate>
+make_boyer_moore_horspool_searcher( _RandomAccessIterator __f, _RandomAccessIterator __l,
+                    _Hash __hf = _Hash(), _BinaryPredicate __p = _BinaryPredicate ())
+{
+    return boyer_moore_horspool_searcher<_RandomAccessIterator, _Hash, _BinaryPredicate>(__f, __l, __hf, __p);
+}
+
+#endif // _LIBCPP_STD_VER > 11
+
+_LIBCPP_END_NAMESPACE_LFTS
+
+_LIBCPP_POP_MACROS
+
+#endif /* _LIBCPP_EXPERIMENTAL_FUNCTIONAL */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/iterator b/contrib/libs/cxxsupp/libcxx/include/experimental/iterator
new file mode 100644
index 00000000000..09ea2cbcc7d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/iterator
@@ -0,0 +1,116 @@
+// -*- C++ -*-
+//===----------------------------- iterator -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_ITERATOR
+#define _LIBCPP_EXPERIMENTAL_ITERATOR
+
+/*
+namespace std {
+  namespace experimental {
+    inline namespace fundamentals_v2 {
+
+    template <class DelimT, class charT = char, class traits = char_traits<charT>>
+        class ostream_joiner {
+        public:
+         typedef charT                        char_type;
+         typedef traits                       traits_type;
+         typedef basic_ostream<charT, traits> ostream_type;
+         typedef output_iterator_tag          iterator_category;
+         typedef void                         value_type;
+         typedef void                         difference_type;
+         typedef void                         pointer;
+         typedef void                         reference;
+
+         ostream_joiner(ostream_type& s, const DelimT& delimiter);
+         ostream_joiner(ostream_type& s, DelimT&& delimiter);
+
+         template<typename T>
+         ostream_joiner& operator=(const T& value);
+
+         ostream_joiner& operator*() noexcept;
+         ostream_joiner& operator++() noexcept;
+         ostream_joiner& operator++(int) noexcept;
+   private:
+      ostream_type* out_stream;   // exposition only
+      DelimT delim;               // exposition only
+      bool first_element;         // exposition only
+   };
+
+  template <class charT, class traits, class DelimT>
+    ostream_joiner<decay_t<DelimT>, charT, traits>
+    make_ostream_joiner(basic_ostream<charT, traits>& os, DelimT&& delimiter);
+
+    } // inline namespace fundamentals_v2
+  } // namespace experimental
+} // namespace std
+
+*/
+
+#include <experimental/__config>
+
+#if _LIBCPP_STD_VER > 11
+
+#include <__memory/addressof.h>
+#include <__utility/move.h>
+#include <__utility/forward.h>
+#include <iterator>
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS
+
+template <class _Delim, class _CharT = char, class _Traits = char_traits<_CharT>>
+class ostream_joiner {
+public:
+
+    typedef _CharT                               char_type;
+    typedef _Traits                              traits_type;
+    typedef basic_ostream<char_type,traits_type> ostream_type;
+    typedef output_iterator_tag                  iterator_category;
+    typedef void                                 value_type;
+    typedef void                                 difference_type;
+    typedef void                                 pointer;
+    typedef void                                 reference;
+
+    ostream_joiner(ostream_type& __os, _Delim&& __d)
+        : __output_iter(_VSTD::addressof(__os)), __delim(_VSTD::move(__d)), __first(true) {}
+
+    ostream_joiner(ostream_type& __os, const _Delim& __d)
+        : __output_iter(_VSTD::addressof(__os)), __delim(__d), __first(true) {}
+
+
+    template<typename _Tp>
+    ostream_joiner& operator=(const _Tp& __v)
+    {
+        if (!__first)
+            *__output_iter << __delim;
+        __first = false;
+        *__output_iter << __v;
+        return *this;
+    }
+
+    ostream_joiner& operator*()     _NOEXCEPT { return *this; }
+    ostream_joiner& operator++()    _NOEXCEPT { return *this; }
+    ostream_joiner& operator++(int) _NOEXCEPT { return *this; }
+
+private:
+    ostream_type*   __output_iter;
+    _Delim          __delim;
+    bool            __first;
+};
+
+
+template <class _CharT, class _Traits, class _Delim>
+ostream_joiner<typename decay<_Delim>::type, _CharT, _Traits>
+make_ostream_joiner(basic_ostream<_CharT, _Traits>& __os, _Delim && __d)
+{ return ostream_joiner<typename decay<_Delim>::type, _CharT, _Traits>(__os, _VSTD::forward<_Delim>(__d)); }
+
+_LIBCPP_END_NAMESPACE_LFTS
+
+#endif /* _LIBCPP_STD_VER > 11 */
+
+#endif // _LIBCPP_EXPERIMENTAL_ITERATOR
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/list b/contrib/libs/cxxsupp/libcxx/include/experimental/list
new file mode 100644
index 00000000000..adc64a8b537
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/list
@@ -0,0 +1,46 @@
+// -*- C++ -*-
+//===--------------------------- list ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_LIST
+#define _LIBCPP_EXPERIMENTAL_LIST
+/*
+    experimental/list synopsis
+
+// C++1z
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+namespace pmr {
+
+  template <class T>
+  using list = std::list<T,polymorphic_allocator<T>>;
+
+} // namespace pmr
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <list>
+#include <experimental/memory_resource>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+template <class _ValueT>
+using list = _VSTD::list<_ValueT, polymorphic_allocator<_ValueT>>;
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR
+
+#endif /* _LIBCPP_EXPERIMENTAL_LIST */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/map b/contrib/libs/cxxsupp/libcxx/include/experimental/map
new file mode 100644
index 00000000000..965d7582c9d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/map
@@ -0,0 +1,56 @@
+// -*- C++ -*-
+//===----------------------------- map ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_MAP
+#define _LIBCPP_EXPERIMENTAL_MAP
+/*
+    experimental/map synopsis
+
+// C++1z
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+namespace pmr {
+
+  template <class Key, class T, class Compare = less<Key>>
+  using map = std::map<Key, T, Compare,
+                       polymorphic_allocator<pair<const Key,T>>>;
+
+  template <class Key, class T, class Compare = less<Key>>
+  using multimap = std::multimap<Key, T, Compare,
+                                 polymorphic_allocator<pair<const Key,T>>>;
+
+} // namespace pmr
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <map>
+#include <experimental/memory_resource>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+template <class _Key, class _Value, class  _Compare = less<_Key>>
+using map = _VSTD::map<_Key, _Value, _Compare,
+                        polymorphic_allocator<pair<const _Key, _Value>>>;
+
+template <class _Key, class _Value, class  _Compare = less<_Key>>
+using multimap = _VSTD::multimap<_Key, _Value, _Compare,
+                        polymorphic_allocator<pair<const _Key, _Value>>>;
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR
+
+#endif /* _LIBCPP_EXPERIMENTAL_MAP */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/memory_resource b/contrib/libs/cxxsupp/libcxx/include/experimental/memory_resource
new file mode 100644
index 00000000000..816d21f5136
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/memory_resource
@@ -0,0 +1,425 @@
+// -*- C++ -*-
+//===------------------------ memory_resource -----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_MEMORY_RESOURCE
+#define _LIBCPP_EXPERIMENTAL_MEMORY_RESOURCE
+
+/**
+    experimental/memory_resource synopsis
+
+// C++1y
+
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+namespace pmr {
+
+  class memory_resource;
+
+  bool operator==(const memory_resource& a,
+                  const memory_resource& b) noexcept;
+  bool operator!=(const memory_resource& a,
+                  const memory_resource& b) noexcept;
+
+  template <class Tp> class polymorphic_allocator;
+
+  template <class T1, class T2>
+  bool operator==(const polymorphic_allocator<T1>& a,
+                  const polymorphic_allocator<T2>& b) noexcept;
+  template <class T1, class T2>
+  bool operator!=(const polymorphic_allocator<T1>& a,
+                  const polymorphic_allocator<T2>& b) noexcept;
+
+  // The name resource_adaptor_imp is for exposition only.
+  template <class Allocator> class resource_adaptor_imp;
+
+  template <class Allocator>
+    using resource_adaptor = resource_adaptor_imp<
+      allocator_traits<Allocator>::rebind_alloc<char>>;
+
+  // Global memory resources
+  memory_resource* new_delete_resource() noexcept;
+  memory_resource* null_memory_resource() noexcept;
+
+  // The default memory resource
+  memory_resource* set_default_resource(memory_resource* r) noexcept;
+  memory_resource* get_default_resource() noexcept;
+
+  // Standard memory resources
+  struct pool_options;
+  class synchronized_pool_resource;
+  class unsynchronized_pool_resource;
+  class monotonic_buffer_resource;
+
+} // namespace pmr
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <experimental/__memory>
+#include <limits>
+#include <memory>
+#include <new>
+#include <stdexcept>
+#include <__tuple>
+#include <type_traits>
+#include <utility>
+#include <cstddef>
+#include <cstdlib>
+#include <__debug>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+// Round __s up to next multiple of __a.
+inline _LIBCPP_INLINE_VISIBILITY
+size_t __aligned_allocation_size(size_t __s, size_t __a) _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__s + __a > __s, "aligned allocation size overflows");
+    return (__s + __a - 1) & ~(__a - 1);
+}
+
+// 8.5, memory.resource
+class _LIBCPP_TYPE_VIS memory_resource
+{
+    static const size_t __max_align = _LIBCPP_ALIGNOF(max_align_t);
+
+// 8.5.2, memory.resource.public
+public:
+    virtual ~memory_resource() = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void* allocate(size_t __bytes, size_t __align = __max_align)
+        { return do_allocate(__bytes, __align); }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void deallocate(void * __p, size_t __bytes, size_t __align = __max_align)
+        { do_deallocate(__p, __bytes, __align); }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool is_equal(memory_resource const & __other) const _NOEXCEPT
+        { return do_is_equal(__other); }
+
+// 8.5.3, memory.resource.priv
+private:
+    virtual void* do_allocate(size_t, size_t) = 0;
+    virtual void do_deallocate(void*, size_t, size_t) = 0;
+    virtual bool do_is_equal(memory_resource const &) const _NOEXCEPT = 0;
+};
+
+// 8.5.4, memory.resource.eq
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator==(memory_resource const & __lhs,
+                memory_resource const & __rhs) _NOEXCEPT
+{
+    return &__lhs == &__rhs || __lhs.is_equal(__rhs);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator!=(memory_resource const & __lhs,
+                memory_resource const & __rhs) _NOEXCEPT
+{
+    return !(__lhs == __rhs);
+}
+
+_LIBCPP_FUNC_VIS
+memory_resource * new_delete_resource() _NOEXCEPT;
+
+_LIBCPP_FUNC_VIS
+memory_resource * null_memory_resource() _NOEXCEPT;
+
+_LIBCPP_FUNC_VIS
+memory_resource * get_default_resource() _NOEXCEPT;
+
+_LIBCPP_FUNC_VIS
+memory_resource * set_default_resource(memory_resource * __new_res) _NOEXCEPT;
+
+// 8.6, memory.polymorphic.allocator.class
+
+// 8.6.1, memory.polymorphic.allocator.overview
+template <class _ValueType>
+class _LIBCPP_TEMPLATE_VIS polymorphic_allocator
+{
+public:
+    typedef _ValueType value_type;
+
+    // 8.6.2, memory.polymorphic.allocator.ctor
+    _LIBCPP_INLINE_VISIBILITY
+    polymorphic_allocator() _NOEXCEPT
+      : __res_(_VSTD_LFTS_PMR::get_default_resource())
+    {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    polymorphic_allocator(memory_resource * __r) _NOEXCEPT
+      : __res_(__r)
+    {}
+
+    polymorphic_allocator(polymorphic_allocator const &) = default;
+
+    template <class _Tp>
+    _LIBCPP_INLINE_VISIBILITY
+    polymorphic_allocator(polymorphic_allocator<_Tp> const & __other) _NOEXCEPT
+      : __res_(__other.resource())
+    {}
+
+    polymorphic_allocator &
+    operator=(polymorphic_allocator const &) = delete;
+
+    // 8.6.3, memory.polymorphic.allocator.mem
+    _LIBCPP_INLINE_VISIBILITY
+    _ValueType* allocate(size_t __n) {
+        if (__n > __max_size()) {
+            __throw_length_error(
+                "std::experimental::pmr::polymorphic_allocator<T>::allocate(size_t n)"
+                " 'n' exceeds maximum supported size");
+        }
+        return static_cast<_ValueType*>(
+            __res_->allocate(__n * sizeof(_ValueType), _LIBCPP_ALIGNOF(_ValueType))
+        );
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void deallocate(_ValueType * __p, size_t __n) _NOEXCEPT {
+        _LIBCPP_ASSERT(__n <= __max_size(),
+                       "deallocate called for size which exceeds max_size()");
+        __res_->deallocate(__p, __n * sizeof(_ValueType), _LIBCPP_ALIGNOF(_ValueType));
+    }
+
+    template <class _Tp, class ..._Ts>
+    _LIBCPP_INLINE_VISIBILITY
+    void construct(_Tp* __p, _Ts &&... __args)
+    {
+        _VSTD_LFTS::__lfts_user_alloc_construct(
+            __p, *this, _VSTD::forward<_Ts>(__args)...
+          );
+    }
+
+    template <class _T1, class _T2, class ..._Args1, class ..._Args2>
+    _LIBCPP_INLINE_VISIBILITY
+    void construct(pair<_T1, _T2>* __p, piecewise_construct_t,
+                   tuple<_Args1...> __x, tuple<_Args2...> __y)
+    {
+        ::new ((void*)__p) pair<_T1, _T2>(piecewise_construct
+          , __transform_tuple(
+              typename __lfts_uses_alloc_ctor<
+                  _T1, polymorphic_allocator&, _Args1...
+              >::type()
+            , _VSTD::move(__x)
+            , typename __make_tuple_indices<sizeof...(_Args1)>::type{}
+          )
+          , __transform_tuple(
+              typename __lfts_uses_alloc_ctor<
+                  _T2, polymorphic_allocator&, _Args2...
+              >::type()
+            , _VSTD::move(__y)
+            , typename __make_tuple_indices<sizeof...(_Args2)>::type{}
+          )
+        );
+    }
+
+    template <class _T1, class _T2>
+    _LIBCPP_INLINE_VISIBILITY
+    void construct(pair<_T1, _T2>* __p) {
+        construct(__p, piecewise_construct, tuple<>(), tuple<>());
+    }
+
+    template <class _T1, class _T2, class _Up, class _Vp>
+    _LIBCPP_INLINE_VISIBILITY
+    void construct(pair<_T1, _T2> * __p, _Up && __u, _Vp && __v) {
+        construct(__p, piecewise_construct
+          , _VSTD::forward_as_tuple(_VSTD::forward<_Up>(__u))
+          , _VSTD::forward_as_tuple(_VSTD::forward<_Vp>(__v)));
+    }
+
+    template <class _T1, class _T2, class _U1, class _U2>
+    _LIBCPP_INLINE_VISIBILITY
+    void construct(pair<_T1, _T2> * __p, pair<_U1, _U2> const & __pr) {
+        construct(__p, piecewise_construct
+            , _VSTD::forward_as_tuple(__pr.first)
+            , _VSTD::forward_as_tuple(__pr.second));
+    }
+
+    template <class _T1, class _T2, class _U1, class _U2>
+    _LIBCPP_INLINE_VISIBILITY
+    void construct(pair<_T1, _T2> * __p, pair<_U1, _U2> && __pr){
+        construct(__p, piecewise_construct
+            , _VSTD::forward_as_tuple(_VSTD::forward<_U1>(__pr.first))
+            , _VSTD::forward_as_tuple(_VSTD::forward<_U2>(__pr.second)));
+    }
+
+    template <class _Tp>
+    _LIBCPP_INLINE_VISIBILITY
+    void destroy(_Tp * __p) _NOEXCEPT
+        { __p->~_Tp(); }
+
+    _LIBCPP_INLINE_VISIBILITY
+    polymorphic_allocator
+    select_on_container_copy_construction() const _NOEXCEPT
+        { return polymorphic_allocator(); }
+
+    _LIBCPP_INLINE_VISIBILITY
+    memory_resource * resource() const _NOEXCEPT
+        { return __res_; }
+
+private:
+    template <class ..._Args, size_t ..._Idx>
+    _LIBCPP_INLINE_VISIBILITY
+    tuple<_Args&&...>
+    __transform_tuple(integral_constant<int, 0>, tuple<_Args...>&& __t,
+                      __tuple_indices<_Idx...>) const
+    {
+        return _VSTD::forward_as_tuple(_VSTD::get<_Idx>(_VSTD::move(__t))...);
+    }
+
+    template <class ..._Args, size_t ..._Idx>
+    _LIBCPP_INLINE_VISIBILITY
+    tuple<allocator_arg_t const&, polymorphic_allocator&, _Args&&...>
+    __transform_tuple(integral_constant<int, 1>, tuple<_Args...> && __t,
+                      __tuple_indices<_Idx...>)
+    {
+        using _Tup = tuple<allocator_arg_t const&, polymorphic_allocator&, _Args&&...>;
+        return _Tup(allocator_arg, *this,
+                    _VSTD::get<_Idx>(_VSTD::move(__t))...);
+    }
+
+    template <class ..._Args, size_t ..._Idx>
+    _LIBCPP_INLINE_VISIBILITY
+    tuple<_Args&&..., polymorphic_allocator&>
+    __transform_tuple(integral_constant<int, 2>, tuple<_Args...> && __t,
+                      __tuple_indices<_Idx...>)
+    {
+        using _Tup = tuple<_Args&&..., polymorphic_allocator&>;
+        return _Tup(_VSTD::get<_Idx>(_VSTD::move(__t))..., *this);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t __max_size() const _NOEXCEPT
+        { return numeric_limits<size_t>::max() / sizeof(value_type); }
+
+    memory_resource * __res_;
+};
+
+// 8.6.4, memory.polymorphic.allocator.eq
+
+template <class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator==(polymorphic_allocator<_Tp> const & __lhs,
+                polymorphic_allocator<_Up> const & __rhs) _NOEXCEPT
+{
+    return *__lhs.resource() == *__rhs.resource();
+}
+
+template <class _Tp, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator!=(polymorphic_allocator<_Tp> const & __lhs,
+                polymorphic_allocator<_Up> const & __rhs) _NOEXCEPT
+{
+    return !(__lhs == __rhs);
+}
+
+// 8.7, memory.resource.adaptor
+
+// 8.7.1, memory.resource.adaptor.overview
+template <class _CharAlloc>
+class _LIBCPP_TEMPLATE_VIS __resource_adaptor_imp
+  : public memory_resource
+{
+    using _CTraits = allocator_traits<_CharAlloc>;
+    static_assert(is_same<typename _CTraits::value_type, char>::value
+               && is_same<typename _CTraits::pointer, char*>::value
+               && is_same<typename _CTraits::void_pointer, void*>::value, "");
+
+    static const size_t _MaxAlign = _LIBCPP_ALIGNOF(max_align_t);
+
+    using _Alloc = typename _CTraits::template rebind_alloc<
+            typename aligned_storage<_MaxAlign, _MaxAlign>::type
+        >;
+
+    using _ValueType = typename _Alloc::value_type;
+
+    _Alloc __alloc_;
+
+public:
+    typedef _CharAlloc allocator_type;
+
+    __resource_adaptor_imp() = default;
+    __resource_adaptor_imp(__resource_adaptor_imp const &) = default;
+    __resource_adaptor_imp(__resource_adaptor_imp &&) = default;
+
+    // 8.7.2, memory.resource.adaptor.ctor
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __resource_adaptor_imp(allocator_type const & __a)
+      : __alloc_(__a)
+    {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __resource_adaptor_imp(allocator_type && __a)
+      : __alloc_(_VSTD::move(__a))
+    {}
+
+    __resource_adaptor_imp &
+    operator=(__resource_adaptor_imp const &) = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const
+    { return __alloc_; }
+
+// 8.7.3, memory.resource.adaptor.mem
+private:
+    virtual void * do_allocate(size_t __bytes, size_t)
+    {
+        if (__bytes > __max_size()) {
+            __throw_length_error(
+                "std::experimental::pmr::resource_adaptor<T>::do_allocate(size_t bytes, size_t align)"
+                " 'bytes' exceeds maximum supported size");
+        }
+        size_t __s = __aligned_allocation_size(__bytes, _MaxAlign) / _MaxAlign;
+        return __alloc_.allocate(__s);
+    }
+
+    virtual void do_deallocate(void * __p, size_t __bytes, size_t)
+    {
+        _LIBCPP_ASSERT(__bytes <= __max_size(),
+            "do_deallocate called for size which exceeds the maximum allocation size");
+        size_t __s = __aligned_allocation_size(__bytes, _MaxAlign) / _MaxAlign;
+        __alloc_.deallocate((_ValueType*)__p, __s);
+    }
+
+    virtual bool do_is_equal(memory_resource const & __other) const _NOEXCEPT {
+        __resource_adaptor_imp const * __p
+          = dynamic_cast<__resource_adaptor_imp const *>(&__other);
+        return __p  ? __alloc_ == __p->__alloc_ : false;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t __max_size() const _NOEXCEPT {
+        return numeric_limits<size_t>::max() - _MaxAlign;
+    }
+};
+
+template <class _Alloc>
+using resource_adaptor = __resource_adaptor_imp<
+    typename allocator_traits<_Alloc>::template rebind_alloc<char>
+  >;
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR
+
+_LIBCPP_POP_MACROS
+
+#endif /* _LIBCPP_EXPERIMENTAL_MEMORY_RESOURCE */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/propagate_const b/contrib/libs/cxxsupp/libcxx/include/experimental/propagate_const
new file mode 100644
index 00000000000..ce4b879b7ea
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/propagate_const
@@ -0,0 +1,577 @@
+// -*- C++ -*-
+//===------------------------ propagate_const -----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_PROPAGATE_CONST
+#define _LIBCPP_EXPERIMENTAL_PROPAGATE_CONST
+/*
+    propagate_const synopsis
+
+    namespace std { namespace experimental { inline namespace fundamentals_v2 {
+
+    // [propagate_const]
+    template <class T> class propagate_const;
+
+    // [propagate_const.underlying], underlying pointer access
+    constexpr const _Tp& _VSTD_LFTS_V2::get_underlying(const propagate_const<T>& pt) noexcept;
+    constexpr T& _VSTD_LFTS_V2::get_underlying(propagate_const<T>& pt) noexcept;
+
+    // [propagate_const.relational], relational operators
+    template <class T> constexpr bool operator==(const propagate_const<T>& pt, nullptr_t);
+    template <class T> constexpr bool operator==(nullptr_t, const propagate_const<T>& pu);
+    template <class T> constexpr bool operator!=(const propagate_const<T>& pt, nullptr_t);
+    template <class T> constexpr bool operator!=(nullptr_t, const propagate_const<T>& pu);
+    template <class T, class U> constexpr bool operator==(const propagate_const<T>& pt, const propagate_const<_Up>& pu);
+    template <class T, class U> constexpr bool operator!=(const propagate_const<T>& pt, const propagate_const<_Up>& pu);
+    template <class T, class U> constexpr bool operator<(const propagate_const<T>& pt, const propagate_const<_Up>& pu);
+    template <class T, class U> constexpr bool operator>(const propagate_const<T>& pt, const propagate_const<_Up>& pu);
+    template <class T, class U> constexpr bool operator<=(const propagate_const<T>& pt, const propagate_const<_Up>& pu);
+    template <class T, class U> constexpr bool operator>=(const propagate_const<T>& pt, const propagate_const<_Up>& pu);
+    template <class T, class U> constexpr bool operator==(const propagate_const<T>& pt, const _Up& u);
+    template <class T, class U> constexpr bool operator!=(const propagate_const<T>& pt, const _Up& u);
+    template <class T, class U> constexpr bool operator<(const propagate_const<T>& pt, const _Up& u);
+    template <class T, class U> constexpr bool operator>(const propagate_const<T>& pt, const _Up& u);
+    template <class T, class U> constexpr bool operator<=(const propagate_const<T>& pt, const _Up& u);
+    template <class T, class U> constexpr bool operator>=(const propagate_const<T>& pt, const _Up& u);
+    template <class T, class U> constexpr bool operator==(const _Tp& t, const propagate_const<_Up>& pu);
+    template <class T, class U> constexpr bool operator!=(const _Tp& t, const propagate_const<_Up>& pu);
+    template <class T, class U> constexpr bool operator<(const _Tp& t, const propagate_const<_Up>& pu);
+    template <class T, class U> constexpr bool operator>(const _Tp& t, const propagate_const<_Up>& pu);
+    template <class T, class U> constexpr bool operator<=(const _Tp& t, const propagate_const<_Up>& pu);
+    template <class T, class U> constexpr bool operator>=(const _Tp& t, const propagate_const<_Up>& pu);
+
+    // [propagate_const.algorithms], specialized algorithms
+    template <class T> constexpr void swap(propagate_const<T>& pt, propagate_const<T>& pu) noexcept(see below);
+
+    template <class T>
+    class propagate_const
+    {
+
+    public:
+      typedef remove_reference_t<decltype(*declval<T&>())> element_type;
+
+      // [propagate_const.ctor], constructors
+      constexpr propagate_const() = default;
+      propagate_const(const propagate_const& p) = delete;
+      constexpr propagate_const(propagate_const&& p) = default;
+      template <class U> EXPLICIT constexpr propagate_const(propagate_const<_Up>&& pu); // see below
+      template <class U> EXPLICIT constexpr propagate_const(U&& u); // see below
+
+      // [propagate_const.assignment], assignment
+      propagate_const& operator=(const propagate_const& p) = delete;
+      constexpr propagate_const& operator=(propagate_const&& p) = default;
+      template <class U> constexpr propagate_const& operator=(propagate_const<_Up>&& pu);
+      template <class U> constexpr propagate_const& operator=(U&& u); // see below
+
+      // [propagate_const.const_observers], const observers
+      explicit constexpr operator bool() const;
+      constexpr const element_type* operator->() const;
+      constexpr operator const element_type*() const; // Not always defined
+      constexpr const element_type& operator*() const;
+      constexpr const element_type* get() const;
+
+      // [propagate_const.non_const_observers], non-const observers
+      constexpr element_type* operator->();
+      constexpr operator element_type*(); // Not always defined
+      constexpr element_type& operator*();
+      constexpr element_type* get();
+
+      // [propagate_const.modifiers], modifiers
+      constexpr void swap(propagate_const& pt) noexcept(see below)
+
+    private:
+      T t_; // exposition only
+    };
+
+  } // namespace fundamentals_v2
+  } // namespace experimental
+
+  // [propagate_const.hash], hash support
+  template <class T> struct hash<experimental::fundamentals_v2::propagate_const<T>>;
+
+  // [propagate_const.comparison_function_objects], comparison function objects
+  template <class T> struct equal_to<experimental::fundamentals_v2::propagate_const<T>>;
+  template <class T> struct not_equal_to<experimental::fundamentals_v2::propagate_const<T>>;
+  template <class T> struct less<experimental::fundamentals_v2::propagate_const<T>>;
+  template <class T> struct greater<experimental::fundamentals_v2::propagate_const<T>>;
+  template <class T> struct less_equal<experimental::fundamentals_v2::propagate_const<T>>;
+  template <class T> struct greater_equal<experimental::fundamentals_v2::propagate_const<T>>;
+
+} // namespace std
+
+*/
+
+#include <experimental/__config>
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER > 11
+
+#include <type_traits>
+#include <utility>
+#include <functional>
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_V2
+
+
+template <class _Tp>
+class propagate_const;
+
+template <class _Up>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+const _Up& get_underlying(const propagate_const<_Up>& __pu) _NOEXCEPT;
+
+template <class _Up>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+_Up& get_underlying(propagate_const<_Up>& __pu) _NOEXCEPT;
+
+template <class _Tp>
+class propagate_const
+{
+public:
+  typedef remove_reference_t<decltype(*declval<_Tp&>())> element_type;
+
+  static_assert(!is_array<_Tp>::value,
+      "Instantiation of propagate_const with an array type is ill-formed.");
+  static_assert(!is_reference<_Tp>::value,
+      "Instantiation of propagate_const with a reference type is ill-formed.");
+  static_assert(!(is_pointer<_Tp>::value && is_function<typename remove_pointer<_Tp>::type>::value),
+      "Instantiation of propagate_const with a function-pointer type is ill-formed.");
+  static_assert(!(is_pointer<_Tp>::value && is_same<typename remove_cv<typename remove_pointer<_Tp>::type>::type, void>::value),
+      "Instantiation of propagate_const with a pointer to (possibly cv-qualified) void is ill-formed.");
+
+private:
+  template <class _Up>
+  static _LIBCPP_CONSTEXPR element_type* __get_pointer(_Up* __u)
+  {
+    return __u;
+  }
+
+  template <class _Up>
+  static _LIBCPP_CONSTEXPR element_type* __get_pointer(_Up& __u)
+  {
+    return __get_pointer(__u.get());
+  }
+
+  template <class _Up>
+  static _LIBCPP_CONSTEXPR const element_type* __get_pointer(const _Up* __u)
+  {
+    return __u;
+  }
+
+  template <class _Up>
+  static _LIBCPP_CONSTEXPR const element_type* __get_pointer(const _Up& __u)
+  {
+    return __get_pointer(__u.get());
+  }
+
+  template <class _Up>
+  struct __is_propagate_const : false_type
+  {
+  };
+
+  template <class _Up>
+  struct __is_propagate_const<propagate_const<_Up>> : true_type
+  {
+  };
+
+  _Tp __t_;
+
+public:
+
+  template <class _Up> friend _LIBCPP_CONSTEXPR const _Up& ::_VSTD_LFTS_V2::get_underlying(const propagate_const<_Up>& __pu) _NOEXCEPT;
+  template <class _Up> friend _LIBCPP_CONSTEXPR _Up& ::_VSTD_LFTS_V2::get_underlying(propagate_const<_Up>& __pu) _NOEXCEPT;
+
+  _LIBCPP_CONSTEXPR propagate_const() = default;
+
+  propagate_const(const propagate_const&) = delete;
+
+  _LIBCPP_CONSTEXPR propagate_const(propagate_const&&) = default;
+
+  template <class _Up, enable_if_t<!is_convertible<_Up, _Tp>::value &&
+                                 is_constructible<_Tp, _Up&&>::value,bool> = true>
+  explicit _LIBCPP_CONSTEXPR propagate_const(propagate_const<_Up>&& __pu)
+      : __t_(std::move(_VSTD_LFTS_V2::get_underlying(__pu)))
+  {
+  }
+
+  template <class _Up, enable_if_t<is_convertible<_Up&&, _Tp>::value &&
+                                 is_constructible<_Tp, _Up&&>::value,bool> = false>
+  _LIBCPP_CONSTEXPR propagate_const(propagate_const<_Up>&& __pu)
+      : __t_(std::move(_VSTD_LFTS_V2::get_underlying(__pu)))
+  {
+  }
+
+  template <class _Up, enable_if_t<!is_convertible<_Up&&, _Tp>::value &&
+                                 is_constructible<_Tp, _Up&&>::value &&
+                                 !__is_propagate_const<decay_t<_Up>>::value,bool> = true>
+  explicit _LIBCPP_CONSTEXPR propagate_const(_Up&& __u)
+      : __t_(std::forward<_Up>(__u))
+  {
+  }
+
+  template <class _Up, enable_if_t<is_convertible<_Up&&, _Tp>::value &&
+                                 is_constructible<_Tp, _Up&&>::value &&
+                                 !__is_propagate_const<decay_t<_Up>>::value,bool> = false>
+  _LIBCPP_CONSTEXPR propagate_const(_Up&& __u)
+      : __t_(std::forward<_Up>(__u))
+  {
+  }
+
+  propagate_const& operator=(const propagate_const&) = delete;
+
+  _LIBCPP_CONSTEXPR propagate_const& operator=(propagate_const&&) = default;
+
+  template <class _Up>
+  _LIBCPP_CONSTEXPR propagate_const& operator=(propagate_const<_Up>&& __pu)
+  {
+    __t_ = std::move(_VSTD_LFTS_V2::get_underlying(__pu));
+    return *this;
+  }
+
+  template <class _Up, class _Vp = enable_if_t<!__is_propagate_const<decay_t<_Up>>::value>>
+  _LIBCPP_CONSTEXPR propagate_const& operator=(_Up&& __u)
+  {
+    __t_ = std::forward<_Up>(__u);
+    return *this;
+  }
+
+  _LIBCPP_CONSTEXPR const element_type* get() const
+  {
+    return __get_pointer(__t_);
+  }
+
+  _LIBCPP_CONSTEXPR element_type* get()
+  {
+    return __get_pointer(__t_);
+  }
+
+  explicit _LIBCPP_CONSTEXPR operator bool() const
+  {
+    return get() != nullptr;
+  }
+
+  _LIBCPP_CONSTEXPR const element_type* operator->() const
+  {
+    return get();
+  }
+
+  template <class _Tp_ = _Tp, class _Up = enable_if_t<is_convertible<
+                                  const _Tp_, const element_type *>::value>>
+  _LIBCPP_CONSTEXPR operator const element_type *() const {
+    return get();
+  }
+
+  _LIBCPP_CONSTEXPR const element_type& operator*() const
+  {
+    return *get();
+  }
+
+  _LIBCPP_CONSTEXPR element_type* operator->()
+  {
+    return get();
+  }
+
+  template <class _Tp_ = _Tp, class _Up = enable_if_t<
+                                  is_convertible<_Tp_, element_type *>::value>>
+  _LIBCPP_CONSTEXPR operator element_type *() {
+    return get();
+  }
+
+  _LIBCPP_CONSTEXPR element_type& operator*()
+  {
+    return *get();
+  }
+
+  _LIBCPP_CONSTEXPR void swap(propagate_const& __pt) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value)
+  {
+    using _VSTD::swap;
+    swap(__t_, __pt.__t_);
+  }
+};
+
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator==(const propagate_const<_Tp>& __pt, nullptr_t)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) == nullptr;
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator==(nullptr_t, const propagate_const<_Tp>& __pt)
+{
+  return nullptr == _VSTD_LFTS_V2::get_underlying(__pt);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator!=(const propagate_const<_Tp>& __pt, nullptr_t)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) != nullptr;
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator!=(nullptr_t, const propagate_const<_Tp>& __pt)
+{
+  return nullptr != _VSTD_LFTS_V2::get_underlying(__pt);
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator==(const propagate_const<_Tp>& __pt,
+                          const propagate_const<_Up>& __pu)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) == _VSTD_LFTS_V2::get_underlying(__pu);
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator!=(const propagate_const<_Tp>& __pt,
+                          const propagate_const<_Up>& __pu)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) != _VSTD_LFTS_V2::get_underlying(__pu);
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator<(const propagate_const<_Tp>& __pt,
+                         const propagate_const<_Up>& __pu)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) < _VSTD_LFTS_V2::get_underlying(__pu);
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator>(const propagate_const<_Tp>& __pt,
+                         const propagate_const<_Up>& __pu)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) > _VSTD_LFTS_V2::get_underlying(__pu);
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator<=(const propagate_const<_Tp>& __pt,
+                          const propagate_const<_Up>& __pu)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) <= _VSTD_LFTS_V2::get_underlying(__pu);
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator>=(const propagate_const<_Tp>& __pt,
+                          const propagate_const<_Up>& __pu)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) >= _VSTD_LFTS_V2::get_underlying(__pu);
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator==(const propagate_const<_Tp>& __pt, const _Up& __u)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) == __u;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator!=(const propagate_const<_Tp>& __pt, const _Up& __u)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) != __u;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator<(const propagate_const<_Tp>& __pt, const _Up& __u)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) < __u;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator>(const propagate_const<_Tp>& __pt, const _Up& __u)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) > __u;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator<=(const propagate_const<_Tp>& __pt, const _Up& __u)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) <= __u;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator>=(const propagate_const<_Tp>& __pt, const _Up& __u)
+{
+  return _VSTD_LFTS_V2::get_underlying(__pt) >= __u;
+}
+
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator==(const _Tp& __t, const propagate_const<_Up>& __pu)
+{
+  return __t == _VSTD_LFTS_V2::get_underlying(__pu);
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator!=(const _Tp& __t, const propagate_const<_Up>& __pu)
+{
+  return __t != _VSTD_LFTS_V2::get_underlying(__pu);
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator<(const _Tp& __t, const propagate_const<_Up>& __pu)
+{
+  return __t < _VSTD_LFTS_V2::get_underlying(__pu);
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator>(const _Tp& __t, const propagate_const<_Up>& __pu)
+{
+  return __t > _VSTD_LFTS_V2::get_underlying(__pu);
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator<=(const _Tp& __t, const propagate_const<_Up>& __pu)
+{
+  return __t <= _VSTD_LFTS_V2::get_underlying(__pu);
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR bool operator>=(const _Tp& __t, const propagate_const<_Up>& __pu)
+{
+  return __t >= _VSTD_LFTS_V2::get_underlying(__pu);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR void swap(propagate_const<_Tp>& __pc1, propagate_const<_Tp>& __pc2) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value)
+{
+  __pc1.swap(__pc2);
+}
+
+template <class _Tp>
+_LIBCPP_CONSTEXPR const _Tp& get_underlying(const propagate_const<_Tp>& __pt) _NOEXCEPT
+{
+  return __pt.__t_;
+}
+
+template <class _Tp>
+_LIBCPP_CONSTEXPR _Tp& get_underlying(propagate_const<_Tp>& __pt) _NOEXCEPT
+{
+  return __pt.__t_;
+}
+
+_LIBCPP_END_NAMESPACE_LFTS_V2
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp>
+struct hash<experimental::fundamentals_v2::propagate_const<_Tp>>
+{
+  typedef size_t result_type;
+  typedef experimental::fundamentals_v2::propagate_const<_Tp> argument_type;
+
+  size_t operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1) const
+  {
+    return std::hash<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1));
+  }
+};
+
+template <class _Tp>
+struct equal_to<experimental::fundamentals_v2::propagate_const<_Tp>>
+{
+  typedef experimental::fundamentals_v2::propagate_const<_Tp> first_argument_type;
+  typedef experimental::fundamentals_v2::propagate_const<_Tp> second_argument_type;
+
+  bool operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1,
+      const experimental::fundamentals_v2::propagate_const<_Tp>& __pc2) const
+  {
+    return std::equal_to<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1), _VSTD_LFTS_V2::get_underlying(__pc2));
+  }
+};
+
+template <class _Tp>
+struct not_equal_to<experimental::fundamentals_v2::propagate_const<_Tp>>
+{
+  typedef experimental::fundamentals_v2::propagate_const<_Tp> first_argument_type;
+  typedef experimental::fundamentals_v2::propagate_const<_Tp> second_argument_type;
+
+  bool operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1,
+      const experimental::fundamentals_v2::propagate_const<_Tp>& __pc2) const
+  {
+    return std::not_equal_to<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1), _VSTD_LFTS_V2::get_underlying(__pc2));
+  }
+};
+
+template <class _Tp>
+struct less<experimental::fundamentals_v2::propagate_const<_Tp>>
+{
+  typedef experimental::fundamentals_v2::propagate_const<_Tp> first_argument_type;
+  typedef experimental::fundamentals_v2::propagate_const<_Tp> second_argument_type;
+
+  bool operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1,
+      const experimental::fundamentals_v2::propagate_const<_Tp>& __pc2) const
+  {
+    return std::less<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1), _VSTD_LFTS_V2::get_underlying(__pc2));
+  }
+};
+
+template <class _Tp>
+struct greater<experimental::fundamentals_v2::propagate_const<_Tp>>
+{
+  typedef experimental::fundamentals_v2::propagate_const<_Tp> first_argument_type;
+  typedef experimental::fundamentals_v2::propagate_const<_Tp> second_argument_type;
+
+  bool operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1,
+      const experimental::fundamentals_v2::propagate_const<_Tp>& __pc2) const
+  {
+    return std::greater<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1), _VSTD_LFTS_V2::get_underlying(__pc2));
+  }
+};
+
+template <class _Tp>
+struct less_equal<experimental::fundamentals_v2::propagate_const<_Tp>>
+{
+  typedef experimental::fundamentals_v2::propagate_const<_Tp> first_argument_type;
+  typedef experimental::fundamentals_v2::propagate_const<_Tp> second_argument_type;
+
+  bool operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1,
+      const experimental::fundamentals_v2::propagate_const<_Tp>& __pc2) const
+  {
+    return std::less_equal<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1), _VSTD_LFTS_V2::get_underlying(__pc2));
+  }
+};
+
+template <class _Tp>
+struct greater_equal<experimental::fundamentals_v2::propagate_const<_Tp>>
+{
+  typedef experimental::fundamentals_v2::propagate_const<_Tp> first_argument_type;
+  typedef experimental::fundamentals_v2::propagate_const<_Tp> second_argument_type;
+
+  bool operator()(const experimental::fundamentals_v2::propagate_const<_Tp>& __pc1,
+      const experimental::fundamentals_v2::propagate_const<_Tp>& __pc2) const
+  {
+    return std::greater_equal<_Tp>()(_VSTD_LFTS_V2::get_underlying(__pc1), _VSTD_LFTS_V2::get_underlying(__pc2));
+  }
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER > 11
+#endif // _LIBCPP_EXPERIMENTAL_PROPAGATE_CONST
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/regex b/contrib/libs/cxxsupp/libcxx/include/experimental/regex
new file mode 100644
index 00000000000..dcd45ac56a8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/regex
@@ -0,0 +1,63 @@
+// -*- C++ -*-
+//===----------------------------- regex ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_REGEX
+#define _LIBCPP_EXPERIMENTAL_REGEX
+/*
+    experimental/regex synopsis
+
+// C++1z
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+namespace pmr {
+
+  template <class BidirectionalIterator>
+  using match_results =
+    std::match_results<BidirectionalIterator,
+                       polymorphic_allocator<sub_match<BidirectionalIterator>>>;
+
+  typedef match_results<const char*> cmatch;
+  typedef match_results<const wchar_t*> wcmatch;
+  typedef match_results<string::const_iterator> smatch;
+  typedef match_results<wstring::const_iterator> wsmatch;
+
+} // namespace pmr
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <regex>
+#include <experimental/string>
+#include <experimental/memory_resource>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+template <class _BiDirIter>
+using match_results =
+    _VSTD::match_results<_BiDirIter,
+        polymorphic_allocator<_VSTD::sub_match<_BiDirIter>>>;
+
+typedef match_results<const char*> cmatch;
+typedef match_results<_VSTD_LFTS_PMR::string::const_iterator> smatch;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef match_results<const wchar_t*> wcmatch;
+typedef match_results<_VSTD_LFTS_PMR::wstring::const_iterator> wsmatch;
+#endif
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR
+
+#endif /* _LIBCPP_EXPERIMENTAL_REGEX */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/set b/contrib/libs/cxxsupp/libcxx/include/experimental/set
new file mode 100644
index 00000000000..52f4df38427
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/set
@@ -0,0 +1,56 @@
+// -*- C++ -*-
+//===--------------------------- list ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_SET
+#define _LIBCPP_EXPERIMENTAL_SET
+/*
+    experimental/set synopsis
+
+// C++1z
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+namespace pmr {
+
+  template <class Key, class T, class Compare = less<Key>>
+  using set = std::set<Key, T, Compare,
+                       polymorphic_allocator<pair<const Key,T>>>;
+
+  template <class Key, class T, class Compare = less<Key>>
+  using multiset = std::multiset<Key, T, Compare,
+                                 polymorphic_allocator<pair<const Key,T>>>;
+
+} // namespace pmr
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <set>
+#include <experimental/memory_resource>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+template <class _Value, class  _Compare = less<_Value>>
+using set = _VSTD::set<_Value, _Compare,
+                        polymorphic_allocator<_Value>>;
+
+template <class _Value, class  _Compare = less<_Value>>
+using multiset = _VSTD::multiset<_Value, _Compare,
+                        polymorphic_allocator<_Value>>;
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR
+
+#endif /* _LIBCPP_EXPERIMENTAL_SET */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/simd b/contrib/libs/cxxsupp/libcxx/include/experimental/simd
new file mode 100644
index 00000000000..59a71395858
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/simd
@@ -0,0 +1,1572 @@
+// -*- C++ -*-
+//===------------------------------- simd ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP_EXPERIMENTAL_SIMD
+#define _LIBCPP_EXPERIMENTAL_SIMD
+
+/*
+    experimental/simd synopsis
+
+namespace std::experimental {
+
+inline namespace parallelism_v2 {
+
+namespace simd_abi {
+
+struct scalar {};
+template <int N> struct fixed_size {};
+template <typename T> inline constexpr int max_fixed_size = implementation-defined;
+template <typename T> using compatible = implementation-defined;
+template <typename T> using native = implementation-defined;
+
+} // simd_abi
+
+struct element_aligned_tag {};
+struct vector_aligned_tag {};
+template <size_t> struct overaligned_tag {};
+inline constexpr element_aligned_tag element_aligned{};
+inline constexpr vector_aligned_tag vector_aligned{};
+template <size_t N> inline constexpr overaligned_tag<N> overaligned{};
+
+// traits [simd.traits]
+template <class T> struct is_abi_tag;
+template <class T> inline constexpr bool is_abi_tag_v = is_abi_tag<T>::value;
+
+template <class T> struct is_simd;
+template <class T> inline constexpr bool is_simd_v = is_simd<T>::value;
+
+template <class T> struct is_simd_mask;
+template <class T> inline constexpr bool is_simd_mask_v = is_simd_mask<T>::value;
+
+template <class T> struct is_simd_flag_type;
+template <class T> inline constexpr bool is_simd_flag_type_v = is_simd_flag_type<T>::value;
+
+template <class T, size_t N> struct abi_for_size { using type = see below; };
+template <class T, size_t N> using abi_for_size_t = typename abi_for_size<T, N>::type;
+
+template <class T, class Abi = simd_abi::compatible<T>> struct simd_size;
+template <class T, class Abi = simd_abi::compatible<T>>
+inline constexpr size_t simd_size_v = simd_size<T, Abi>::value;
+
+template <class T, class U = typename T::value_type> struct memory_alignment;
+template <class T, class U = typename T::value_type>
+inline constexpr size_t memory_alignment_v = memory_alignment<T, U>::value;
+
+// class template simd [simd.class]
+template <class T, class Abi = simd_abi::compatible<T>> class simd;
+template <class T> using native_simd = simd<T, simd_abi::native<T>>;
+template <class T, int N> using fixed_size_simd = simd<T, simd_abi::fixed_size<N>>;
+
+// class template simd_mask [simd.mask.class]
+template <class T, class Abi = simd_abi::compatible<T>> class simd_mask;
+template <class T> using native_simd_mask = simd_mask<T, simd_abi::native<T>>;
+template <class T, int N> using fixed_size_simd_mask = simd_mask<T, simd_abi::fixed_size<N>>;
+
+// casts [simd.casts]
+template <class T, class U, class Abi> see below simd_cast(const simd<U, Abi>&);
+template <class T, class U, class Abi> see below static_simd_cast(const simd<U, Abi>&);
+
+template <class T, class Abi>
+fixed_size_simd<T, simd_size_v<T, Abi>> to_fixed_size(const simd<T, Abi>&) noexcept;
+template <class T, class Abi>
+fixed_size_simd_mask<T, simd_size_v<T, Abi>> to_fixed_size(const simd_mask<T, Abi>&) noexcept;
+template <class T, size_t N> native_simd<T> to_native(const fixed_size_simd<T, N>&) noexcept;
+template <class T, size_t N>
+native_simd_mask<T> to_native(const fixed_size_simd_mask<T, N>> &) noexcept;
+template <class T, size_t N> simd<T> to_compatible(const fixed_size_simd<T, N>&) noexcept;
+template <class T, size_t N> simd_mask<T> to_compatible(const fixed_size_simd_mask<T, N>&) noexcept;
+
+template <size_t... Sizes, class T, class Abi>
+tuple<simd<T, abi_for_size_t<Sizes>>...> split(const simd<T, Abi>&);
+template <size_t... Sizes, class T, class Abi>
+tuple<simd_mask<T, abi_for_size_t<Sizes>>...> split(const simd_mask<T, Abi>&);
+template <class V, class Abi>
+array<V, simd_size_v<typename V::value_type, Abi> / V::size()> split(
+const simd<typename V::value_type, Abi>&);
+template <class V, class Abi>
+array<V, simd_size_v<typename V::value_type, Abi> / V::size()> split(
+const simd_mask<typename V::value_type, Abi>&);
+
+template <class T, class... Abis>
+simd<T, abi_for_size_t<T, (simd_size_v<T, Abis> + ...)>> concat(const simd<T, Abis>&...);
+template <class T, class... Abis>
+simd_mask<T, abi_for_size_t<T, (simd_size_v<T, Abis> + ...)>> concat(const simd_mask<T, Abis>&...);
+
+// reductions [simd.mask.reductions]
+template <class T, class Abi> bool all_of(const simd_mask<T, Abi>&) noexcept;
+template <class T, class Abi> bool any_of(const simd_mask<T, Abi>&) noexcept;
+template <class T, class Abi> bool none_of(const simd_mask<T, Abi>&) noexcept;
+template <class T, class Abi> bool some_of(const simd_mask<T, Abi>&) noexcept;
+template <class T, class Abi> int popcount(const simd_mask<T, Abi>&) noexcept;
+template <class T, class Abi> int find_first_set(const simd_mask<T, Abi>&);
+template <class T, class Abi> int find_last_set(const simd_mask<T, Abi>&);
+
+bool all_of(see below) noexcept;
+bool any_of(see below) noexcept;
+bool none_of(see below) noexcept;
+bool some_of(see below) noexcept;
+int popcount(see below) noexcept;
+int find_first_set(see below) noexcept;
+int find_last_set(see below) noexcept;
+
+// masked assignment [simd.whereexpr]
+template <class M, class T> class const_where_expression;
+template <class M, class T> class where_expression;
+
+// masked assignment [simd.mask.where]
+template <class T> struct nodeduce { using type = T; }; // exposition only
+
+template <class T> using nodeduce_t = typename nodeduce<T>::type; // exposition only
+
+template <class T, class Abi>
+where_expression<simd_mask<T, Abi>, simd<T, Abi>>
+where(const typename simd<T, Abi>::mask_type&, simd<T, Abi>&) noexcept;
+
+template <class T, class Abi>
+const_where_expression<simd_mask<T, Abi>, const simd<T, Abi>>
+where(const typename simd<T, Abi>::mask_type&, const simd<T, Abi>&) noexcept;
+
+template <class T, class Abi>
+where_expression<simd_mask<T, Abi>, simd_mask<T, Abi>>
+where(const nodeduce_t<simd_mask<T, Abi>>&, simd_mask<T, Abi>&) noexcept;
+
+template <class T, class Abi>
+const_where_expression<simd_mask<T, Abi>, const simd_mask<T, Abi>>
+where(const nodeduce_t<simd_mask<T, Abi>>&, const simd_mask<T, Abi>&) noexcept;
+
+template <class T> where_expression<bool, T> where(see below k, T& d) noexcept;
+
+template <class T>
+const_where_expression<bool, const T> where(see below k, const T& d) noexcept;
+
+// reductions [simd.reductions]
+template <class T, class Abi, class BinaryOperation = std::plus<>>
+T reduce(const simd<T, Abi>&, BinaryOperation = BinaryOperation());
+
+template <class M, class V, class BinaryOperation>
+typename V::value_type reduce(const const_where_expression<M, V>& x,
+typename V::value_type neutral_element, BinaryOperation binary_op);
+
+template <class M, class V>
+typename V::value_type reduce(const const_where_expression<M, V>& x, plus<> binary_op = plus<>());
+
+template <class M, class V>
+typename V::value_type reduce(const const_where_expression<M, V>& x, multiplies<> binary_op);
+
+template <class M, class V>
+typename V::value_type reduce(const const_where_expression<M, V>& x, bit_and<> binary_op);
+
+template <class M, class V>
+typename V::value_type reduce(const const_where_expression<M, V>& x, bit_or<> binary_op);
+
+template <class M, class V>
+typename V::value_type reduce(const const_where_expression<M, V>& x, bit_xor<> binary_op);
+
+template <class T, class Abi> T hmin(const simd<T, Abi>&);
+template <class M, class V> T hmin(const const_where_expression<M, V>&);
+template <class T, class Abi> T hmax(const simd<T, Abi>&);
+template <class M, class V> T hmax(const const_where_expression<M, V>&);
+
+// algorithms [simd.alg]
+template <class T, class Abi> simd<T, Abi> min(const simd<T, Abi>&, const simd<T, Abi>&) noexcept;
+
+template <class T, class Abi> simd<T, Abi> max(const simd<T, Abi>&, const simd<T, Abi>&) noexcept;
+
+template <class T, class Abi>
+std::pair<simd<T, Abi>, simd<T, Abi>> minmax(const simd<T, Abi>&, const simd<T, Abi>&) noexcept;
+
+template <class T, class Abi>
+simd<T, Abi> clamp(const simd<T, Abi>& v, const simd<T, Abi>& lo, const simd<T, Abi>& hi);
+
+// [simd.whereexpr]
+template <class M, class T>
+class const_where_expression {
+  const M& mask; // exposition only
+  T& data; // exposition only
+public:
+  const_where_expression(const const_where_expression&) = delete;
+  const_where_expression& operator=(const const_where_expression&) = delete;
+  remove_const_t<T> operator-() const &&;
+  template <class U, class Flags> void copy_to(U* mem, Flags f) const &&;
+};
+
+template <class M, class T>
+class where_expression : public const_where_expression<M, T> {
+public:
+  where_expression(const where_expression&) = delete;
+  where_expression& operator=(const where_expression&) = delete;
+  template <class U> void operator=(U&& x);
+  template <class U> void operator+=(U&& x);
+  template <class U> void operator-=(U&& x);
+  template <class U> void operator*=(U&& x);
+  template <class U> void operator/=(U&& x);
+  template <class U> void operator%=(U&& x);
+  template <class U> void operator&=(U&& x);
+  template <class U> void operator|=(U&& x);
+  template <class U> void operator^=(U&& x);
+  template <class U> void operator<<=(U&& x);
+  template <class U> void operator>>=(U&& x);
+  void operator++();
+  void operator++(int);
+  void operator--();
+  void operator--(int);
+  template <class U, class Flags> void copy_from(const U* mem, Flags);
+};
+
+// [simd.class]
+template <class T, class Abi> class simd {
+public:
+  using value_type = T;
+  using reference = see below;
+  using mask_type = simd_mask<T, Abi>;
+
+  using abi_type = Abi;
+  static constexpr size_t size() noexcept;
+  simd() = default;
+
+  // implicit type conversion constructor
+  template <class U> simd(const simd<U, simd_abi::fixed_size<size()>>&);
+
+  // implicit broadcast constructor (see below for constraints)
+  template <class U> simd(U&& value);
+
+  // generator constructor (see below for constraints)
+  template <class G> explicit simd(G&& gen);
+
+  // load constructor
+  template <class U, class Flags> simd(const U* mem, Flags f);
+
+  // loads [simd.load]
+  template <class U, class Flags> void copy_from(const U* mem, Flags f);
+
+  // stores [simd.store]
+  template <class U, class Flags> void copy_to(U* mem, Flags f) const;
+
+  // scalar access [simd.subscr]
+  reference operator[](size_t);
+  value_type operator[](size_t) const;
+
+  // unary operators [simd.unary]
+  simd& operator++();
+  simd operator++(int);
+  simd& operator--();
+  simd operator--(int);
+  mask_type operator!() const;
+  simd operator~() const; // see below
+  simd operator+() const;
+  simd operator-() const;
+
+  // binary operators [simd.binary]
+  friend simd operator+ (const simd&, const simd&);
+  friend simd operator- (const simd&, const simd&);
+  friend simd operator* (const simd&, const simd&);
+  friend simd operator/ (const simd&, const simd&);
+  friend simd operator% (const simd&, const simd&);
+  friend simd operator& (const simd&, const simd&);
+  friend simd operator| (const simd&, const simd&);
+  friend simd operator^ (const simd&, const simd&);
+  friend simd operator<<(const simd&, const simd&);
+  friend simd operator>>(const simd&, const simd&);
+  friend simd operator<<(const simd&, int);
+  friend simd operator>>(const simd&, int);
+
+  // compound assignment [simd.cassign]
+  friend simd& operator+= (simd&, const simd&);
+  friend simd& operator-= (simd&, const simd&);
+  friend simd& operator*= (simd&, const simd&);
+  friend simd& operator/= (simd&, const simd&);
+  friend simd& operator%= (simd&, const simd&);
+
+  friend simd& operator&= (simd&, const simd&);
+  friend simd& operator|= (simd&, const simd&);
+  friend simd& operator^= (simd&, const simd&);
+  friend simd& operator<<=(simd&, const simd&);
+  friend simd& operator>>=(simd&, const simd&);
+  friend simd& operator<<=(simd&, int);
+  friend simd& operator>>=(simd&, int);
+
+  // compares [simd.comparison]
+  friend mask_type operator==(const simd&, const simd&);
+  friend mask_type operator!=(const simd&, const simd&);
+  friend mask_type operator>=(const simd&, const simd&);
+  friend mask_type operator<=(const simd&, const simd&);
+  friend mask_type operator> (const simd&, const simd&);
+  friend mask_type operator< (const simd&, const simd&);
+};
+
+// [simd.math]
+template <class Abi> using scharv = simd<signed char, Abi>; // exposition only
+template <class Abi> using shortv = simd<short, Abi>; // exposition only
+template <class Abi> using intv = simd<int, Abi>; // exposition only
+template <class Abi> using longv = simd<long int, Abi>; // exposition only
+template <class Abi> using llongv = simd<long long int, Abi>; // exposition only
+template <class Abi> using floatv = simd<float, Abi>; // exposition only
+template <class Abi> using doublev = simd<double, Abi>; // exposition only
+template <class Abi> using ldoublev = simd<long double, Abi>; // exposition only
+template <class T, class V> using samesize = fixed_size_simd<T, V::size()>; // exposition only
+
+template <class Abi> floatv<Abi> acos(floatv<Abi> x);
+template <class Abi> doublev<Abi> acos(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> acos(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> asin(floatv<Abi> x);
+template <class Abi> doublev<Abi> asin(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> asin(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> atan(floatv<Abi> x);
+template <class Abi> doublev<Abi> atan(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> atan(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> atan2(floatv<Abi> y, floatv<Abi> x);
+template <class Abi> doublev<Abi> atan2(doublev<Abi> y, doublev<Abi> x);
+template <class Abi> ldoublev<Abi> atan2(ldoublev<Abi> y, ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> cos(floatv<Abi> x);
+template <class Abi> doublev<Abi> cos(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> cos(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> sin(floatv<Abi> x);
+template <class Abi> doublev<Abi> sin(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> sin(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> tan(floatv<Abi> x);
+template <class Abi> doublev<Abi> tan(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> tan(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> acosh(floatv<Abi> x);
+template <class Abi> doublev<Abi> acosh(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> acosh(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> asinh(floatv<Abi> x);
+template <class Abi> doublev<Abi> asinh(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> asinh(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> atanh(floatv<Abi> x);
+template <class Abi> doublev<Abi> atanh(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> atanh(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> cosh(floatv<Abi> x);
+template <class Abi> doublev<Abi> cosh(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> cosh(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> sinh(floatv<Abi> x);
+template <class Abi> doublev<Abi> sinh(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> sinh(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> tanh(floatv<Abi> x);
+template <class Abi> doublev<Abi> tanh(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> tanh(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> exp(floatv<Abi> x);
+template <class Abi> doublev<Abi> exp(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> exp(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> exp2(floatv<Abi> x);
+template <class Abi> doublev<Abi> exp2(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> exp2(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> expm1(floatv<Abi> x);
+template <class Abi> doublev<Abi> expm1(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> expm1(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> frexp(floatv<Abi> value, samesize<int, floatv<Abi>>* exp);
+template <class Abi> doublev<Abi> frexp(doublev<Abi> value, samesize<int, doublev<Abi>>* exp);
+template <class Abi> ldoublev<Abi> frexp(ldoublev<Abi> value, samesize<int, ldoublev<Abi>>* exp);
+
+template <class Abi> samesize<int, floatv<Abi>> ilogb(floatv<Abi> x);
+template <class Abi> samesize<int, doublev<Abi>> ilogb(doublev<Abi> x);
+template <class Abi> samesize<int, ldoublev<Abi>> ilogb(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> ldexp(floatv<Abi> x, samesize<int, floatv<Abi>> exp);
+template <class Abi> doublev<Abi> ldexp(doublev<Abi> x, samesize<int, doublev<Abi>> exp);
+template <class Abi> ldoublev<Abi> ldexp(ldoublev<Abi> x, samesize<int, ldoublev<Abi>> exp);
+
+template <class Abi> floatv<Abi> log(floatv<Abi> x);
+template <class Abi> doublev<Abi> log(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> log(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> log10(floatv<Abi> x);
+template <class Abi> doublev<Abi> log10(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> log10(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> log1p(floatv<Abi> x);
+template <class Abi> doublev<Abi> log1p(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> log1p(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> log2(floatv<Abi> x);
+template <class Abi> doublev<Abi> log2(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> log2(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> logb(floatv<Abi> x);
+template <class Abi> doublev<Abi> logb(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> logb(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> modf(floatv<Abi> value, floatv<Abi>* iptr);
+template <class Abi> doublev<Abi> modf(doublev<Abi> value, doublev<Abi>* iptr);
+template <class Abi> ldoublev<Abi> modf(ldoublev<Abi> value, ldoublev<Abi>* iptr);
+
+template <class Abi> floatv<Abi> scalbn(floatv<Abi> x, samesize<int, floatv<Abi>> n);
+template <class Abi> doublev<Abi> scalbn(doublev<Abi> x, samesize<int, doublev<Abi>> n);
+template <class Abi> ldoublev<Abi> scalbn(ldoublev<Abi> x, samesize<int, ldoublev<Abi>> n);
+template <class Abi> floatv<Abi> scalbln(floatv<Abi> x, samesize<long int, floatv<Abi>> n);
+template <class Abi> doublev<Abi> scalbln(doublev<Abi> x, samesize<long int, doublev<Abi>> n);
+template <class Abi> ldoublev<Abi> scalbln(ldoublev<Abi> x, samesize<long int, ldoublev<Abi>> n);
+
+template <class Abi> floatv<Abi> cbrt(floatv<Abi> x);
+template <class Abi> doublev<Abi> cbrt(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> cbrt(ldoublev<Abi> x);
+
+template <class Abi> scharv<Abi> abs(scharv<Abi> j);
+template <class Abi> shortv<Abi> abs(shortv<Abi> j);
+template <class Abi> intv<Abi> abs(intv<Abi> j);
+template <class Abi> longv<Abi> abs(longv<Abi> j);
+template <class Abi> llongv<Abi> abs(llongv<Abi> j);
+template <class Abi> floatv<Abi> abs(floatv<Abi> j);
+template <class Abi> doublev<Abi> abs(doublev<Abi> j);
+template <class Abi> ldoublev<Abi> abs(ldoublev<Abi> j);
+
+template <class Abi> floatv<Abi> hypot(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> doublev<Abi> hypot(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> ldoublev<Abi> hypot(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> floatv<Abi> hypot(floatv<Abi> x, floatv<Abi> y, floatv<Abi> z);
+template <class Abi> doublev<Abi> hypot(doublev<Abi> x, doublev<Abi> y, doublev<Abi> z);
+template <class Abi> ldoublev<Abi> hypot(ldoublev<Abi> x, ldoublev<Abi> y, ldoublev<Abi> z);
+
+template <class Abi> floatv<Abi> pow(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> doublev<Abi> pow(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> ldoublev<Abi> pow(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> floatv<Abi> sqrt(floatv<Abi> x);
+template <class Abi> doublev<Abi> sqrt(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> sqrt(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> erf(floatv<Abi> x);
+template <class Abi> doublev<Abi> erf(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> erf(ldoublev<Abi> x);
+template <class Abi> floatv<Abi> erfc(floatv<Abi> x);
+template <class Abi> doublev<Abi> erfc(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> erfc(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> lgamma(floatv<Abi> x);
+template <class Abi> doublev<Abi> lgamma(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> lgamma(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> tgamma(floatv<Abi> x);
+template <class Abi> doublev<Abi> tgamma(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> tgamma(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> ceil(floatv<Abi> x);
+template <class Abi> doublev<Abi> ceil(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> ceil(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> floor(floatv<Abi> x);
+template <class Abi> doublev<Abi> floor(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> floor(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> nearbyint(floatv<Abi> x);
+template <class Abi> doublev<Abi> nearbyint(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> nearbyint(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> rint(floatv<Abi> x);
+template <class Abi> doublev<Abi> rint(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> rint(ldoublev<Abi> x);
+
+template <class Abi> samesize<long int, floatv<Abi>> lrint(floatv<Abi> x);
+template <class Abi> samesize<long int, doublev<Abi>> lrint(doublev<Abi> x);
+template <class Abi> samesize<long int, ldoublev<Abi>> lrint(ldoublev<Abi> x);
+template <class Abi> samesize<long long int, floatv<Abi>> llrint(floatv<Abi> x);
+template <class Abi> samesize<long long int, doublev<Abi>> llrint(doublev<Abi> x);
+template <class Abi> samesize<long long int, ldoublev<Abi>> llrint(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> round(floatv<Abi> x);
+template <class Abi> doublev<Abi> round(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> round(ldoublev<Abi> x);
+template <class Abi> samesize<long int, floatv<Abi>> lround(floatv<Abi> x);
+template <class Abi> samesize<long int, doublev<Abi>> lround(doublev<Abi> x);
+template <class Abi> samesize<long int, ldoublev<Abi>> lround(ldoublev<Abi> x);
+template <class Abi> samesize<long long int, floatv<Abi>> llround(floatv<Abi> x);
+template <class Abi> samesize<long long int, doublev<Abi>> llround(doublev<Abi> x);
+template <class Abi> samesize<long long int, ldoublev<Abi>> llround(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> trunc(floatv<Abi> x);
+template <class Abi> doublev<Abi> trunc(doublev<Abi> x);
+template <class Abi> ldoublev<Abi> trunc(ldoublev<Abi> x);
+
+template <class Abi> floatv<Abi> fmod(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> doublev<Abi> fmod(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> ldoublev<Abi> fmod(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> floatv<Abi> remainder(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> doublev<Abi> remainder(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> ldoublev<Abi> remainder(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> floatv<Abi> remquo(floatv<Abi> x, floatv<Abi> y, samesize<int, floatv<Abi>>* quo);
+template <class Abi> doublev<Abi> remquo(doublev<Abi> x, doublev<Abi> y, samesize<int, doublev<Abi>>* quo);
+template <class Abi> ldoublev<Abi> remquo(ldoublev<Abi> x, ldoublev<Abi> y, samesize<int, ldoublev<Abi>>* quo);
+
+template <class Abi> floatv<Abi> copysign(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> doublev<Abi> copysign(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> ldoublev<Abi> copysign(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> doublev<Abi> nan(const char* tagp);
+template <class Abi> floatv<Abi> nanf(const char* tagp);
+template <class Abi> ldoublev<Abi> nanl(const char* tagp);
+
+template <class Abi> floatv<Abi> nextafter(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> doublev<Abi> nextafter(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> ldoublev<Abi> nextafter(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> floatv<Abi> nexttoward(floatv<Abi> x, ldoublev<Abi> y);
+template <class Abi> doublev<Abi> nexttoward(doublev<Abi> x, ldoublev<Abi> y);
+template <class Abi> ldoublev<Abi> nexttoward(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> floatv<Abi> fdim(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> doublev<Abi> fdim(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> ldoublev<Abi> fdim(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> floatv<Abi> fmax(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> doublev<Abi> fmax(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> ldoublev<Abi> fmax(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> floatv<Abi> fmin(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> doublev<Abi> fmin(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> ldoublev<Abi> fmin(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> floatv<Abi> fma(floatv<Abi> x, floatv<Abi> y, floatv<Abi> z);
+template <class Abi> doublev<Abi> fma(doublev<Abi> x, doublev<Abi> y, doublev<Abi> z);
+template <class Abi> ldoublev<Abi> fma(ldoublev<Abi> x, ldoublev<Abi> y, ldoublev<Abi> z);
+
+template <class Abi> samesize<int, floatv<Abi>> fpclassify(floatv<Abi> x);
+template <class Abi> samesize<int, doublev<Abi>> fpclassify(doublev<Abi> x);
+template <class Abi> samesize<int, ldoublev<Abi>> fpclassify(ldoublev<Abi> x);
+
+template <class Abi> simd_mask<float, Abi> isfinite(floatv<Abi> x);
+template <class Abi> simd_mask<double, Abi> isfinite(doublev<Abi> x);
+template <class Abi> simd_mask<long double, Abi> isfinite(ldoublev<Abi> x);
+
+template <class Abi> simd_mask<float, Abi> isinf(floatv<Abi> x);
+template <class Abi> simd_mask<double, Abi> isinf(doublev<Abi> x);
+template <class Abi> simd_mask<long double, Abi> isinf(ldoublev<Abi> x);
+
+template <class Abi> simd_mask<float, Abi> isnan(floatv<Abi> x);
+template <class Abi> simd_mask<double, Abi> isnan(doublev<Abi> x);
+template <class Abi> simd_mask<long double, Abi> isnan(ldoublev<Abi> x);
+
+template <class Abi> simd_mask<float, Abi> isnormal(floatv<Abi> x);
+template <class Abi> simd_mask<double, Abi> isnormal(doublev<Abi> x);
+template <class Abi> simd_mask<long double, Abi> isnormal(ldoublev<Abi> x);
+
+template <class Abi> simd_mask<float, Abi> signbit(floatv<Abi> x);
+template <class Abi> simd_mask<double, Abi> signbit(doublev<Abi> x);
+template <class Abi> simd_mask<long double, Abi> signbit(ldoublev<Abi> x);
+
+template <class Abi> simd_mask<float, Abi> isgreater(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> simd_mask<double, Abi> isgreater(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> simd_mask<long double, Abi> isgreater(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> simd_mask<float, Abi> isgreaterequal(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> simd_mask<double, Abi> isgreaterequal(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> simd_mask<long double, Abi> isgreaterequal(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> simd_mask<float, Abi> isless(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> simd_mask<double, Abi> isless(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> simd_mask<long double, Abi> isless(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> simd_mask<float, Abi> islessequal(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> simd_mask<double, Abi> islessequal(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> simd_mask<long double, Abi> islessequal(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> simd_mask<float, Abi> islessgreater(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> simd_mask<double, Abi> islessgreater(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> simd_mask<long double, Abi> islessgreater(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class Abi> simd_mask<float, Abi> isunordered(floatv<Abi> x, floatv<Abi> y);
+template <class Abi> simd_mask<double, Abi> isunordered(doublev<Abi> x, doublev<Abi> y);
+template <class Abi> simd_mask<long double, Abi> isunordered(ldoublev<Abi> x, ldoublev<Abi> y);
+
+template <class V> struct simd_div_t { V quot, rem; };
+template <class Abi> simd_div_t<scharv<Abi>> div(scharv<Abi> numer, scharv<Abi> denom);
+template <class Abi> simd_div_t<shortv<Abi>> div(shortv<Abi> numer, shortv<Abi> denom);
+template <class Abi> simd_div_t<intv<Abi>> div(intv<Abi> numer, intv<Abi> denom);
+template <class Abi> simd_div_t<longv<Abi>> div(longv<Abi> numer, longv<Abi> denom);
+template <class Abi> simd_div_t<llongv<Abi>> div(llongv<Abi> numer, llongv<Abi> denom);
+
+// [simd.mask.class]
+template <class T, class Abi>
+class simd_mask {
+public:
+  using value_type = bool;
+  using reference = see below;
+  using simd_type = simd<T, Abi>;
+  using abi_type = Abi;
+  static constexpr size_t size() noexcept;
+  simd_mask() = default;
+
+  // broadcast constructor
+  explicit simd_mask(value_type) noexcept;
+
+  // implicit type conversion constructor
+  template <class U> simd_mask(const simd_mask<U, simd_abi::fixed_size<size()>>&) noexcept;
+
+  // load constructor
+  template <class Flags> simd_mask(const value_type* mem, Flags);
+
+  // loads [simd.mask.copy]
+  template <class Flags> void copy_from(const value_type* mem, Flags);
+  template <class Flags> void copy_to(value_type* mem, Flags) const;
+
+  // scalar access [simd.mask.subscr]
+  reference operator[](size_t);
+  value_type operator[](size_t) const;
+
+  // unary operators [simd.mask.unary]
+  simd_mask operator!() const noexcept;
+
+  // simd_mask binary operators [simd.mask.binary]
+  friend simd_mask operator&&(const simd_mask&, const simd_mask&) noexcept;
+  friend simd_mask operator||(const simd_mask&, const simd_mask&) noexcept;
+  friend simd_mask operator& (const simd_mask&, const simd_mask&) noexcept;
+  friend simd_mask operator| (const simd_mask&, const simd_mask&) noexcept;
+  friend simd_mask operator^ (const simd_mask&, const simd_mask&) noexcept;
+
+  // simd_mask compound assignment [simd.mask.cassign]
+  friend simd_mask& operator&=(simd_mask&, const simd_mask&) noexcept;
+  friend simd_mask& operator|=(simd_mask&, const simd_mask&) noexcept;
+  friend simd_mask& operator^=(simd_mask&, const simd_mask&) noexcept;
+
+  // simd_mask compares [simd.mask.comparison]
+  friend simd_mask operator==(const simd_mask&, const simd_mask&) noexcept;
+  friend simd_mask operator!=(const simd_mask&, const simd_mask&) noexcept;
+};
+
+} // parallelism_v2
+} // std::experimental
+
+*/
+
+#include <experimental/__config>
+#include <algorithm>
+#include <array>
+#include <cstddef>
+#include <functional>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_SIMD
+
+#if _LIBCPP_STD_VER >= 17
+
+enum class _StorageKind {
+  _Scalar,
+  _Array,
+  _VecExt,
+};
+
+template <_StorageKind __kind, int _Np>
+struct __simd_abi {};
+
+template <class _Tp, class _Abi>
+class __simd_storage {};
+
+template <class _Tp, int __num_element>
+class __simd_storage<_Tp, __simd_abi<_StorageKind::_Array, __num_element>> {
+  std::array<_Tp, __num_element> __storage_;
+
+  template <class, class>
+  friend struct simd;
+
+  template <class, class>
+  friend struct simd_mask;
+
+public:
+  _Tp __get(size_t __index) const noexcept { return __storage_[__index]; };
+  void __set(size_t __index, _Tp __val) noexcept {
+    __storage_[__index] = __val;
+  }
+};
+
+template <class _Tp>
+class __simd_storage<_Tp, __simd_abi<_StorageKind::_Scalar, 1>> {
+  _Tp __storage_;
+
+  template <class, class>
+  friend struct simd;
+
+  template <class, class>
+  friend struct simd_mask;
+
+public:
+  _Tp __get(size_t __index) const noexcept { return (&__storage_)[__index]; };
+  void __set(size_t __index, _Tp __val) noexcept {
+    (&__storage_)[__index] = __val;
+  }
+};
+
+#ifndef _LIBCPP_HAS_NO_VECTOR_EXTENSION
+
+constexpr size_t __floor_pow_of_2(size_t __val) {
+  return ((__val - 1) & __val) == 0 ? __val
+                                    : __floor_pow_of_2((__val - 1) & __val);
+}
+
+constexpr size_t __ceil_pow_of_2(size_t __val) {
+  return __val == 1 ? 1 : __floor_pow_of_2(__val - 1) << 1;
+}
+
+template <class _Tp, size_t __bytes>
+struct __vec_ext_traits {
+#if !defined(_LIBCPP_COMPILER_CLANG_BASED)
+  typedef _Tp type __attribute__((vector_size(__ceil_pow_of_2(__bytes))));
+#endif
+};
+
+#if defined(_LIBCPP_COMPILER_CLANG_BASED)
+#define _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, _NUM_ELEMENT)                        \
+  template <>                                                                  \
+  struct __vec_ext_traits<_TYPE, sizeof(_TYPE) * _NUM_ELEMENT> {               \
+    using type =                                                               \
+        _TYPE __attribute__((vector_size(sizeof(_TYPE) * _NUM_ELEMENT)));      \
+  }
+
+#define _LIBCPP_SPECIALIZE_VEC_EXT_32(_TYPE)                                   \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 1);                                        \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 2);                                        \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 3);                                        \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 4);                                        \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 5);                                        \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 6);                                        \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 7);                                        \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 8);                                        \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 9);                                        \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 10);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 11);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 12);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 13);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 14);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 15);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 16);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 17);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 18);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 19);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 20);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 21);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 22);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 23);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 24);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 25);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 26);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 27);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 28);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 29);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 30);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 31);                                       \
+  _LIBCPP_SPECIALIZE_VEC_EXT(_TYPE, 32);
+
+_LIBCPP_SPECIALIZE_VEC_EXT_32(char);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(char16_t);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(char32_t);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(wchar_t);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(signed char);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(signed short);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(signed int);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(signed long);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(signed long long);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(unsigned char);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(unsigned short);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(unsigned int);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(unsigned long);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(unsigned long long);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(float);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(double);
+_LIBCPP_SPECIALIZE_VEC_EXT_32(long double);
+
+#undef _LIBCPP_SPECIALIZE_VEC_EXT_32
+#undef _LIBCPP_SPECIALIZE_VEC_EXT
+#endif
+
+template <class _Tp, int __num_element>
+class __simd_storage<_Tp, __simd_abi<_StorageKind::_VecExt, __num_element>> {
+  using _StorageType =
+      typename __vec_ext_traits<_Tp, sizeof(_Tp) * __num_element>::type;
+
+  _StorageType __storage_;
+
+  template <class, class>
+  friend struct simd;
+
+  template <class, class>
+  friend struct simd_mask;
+
+public:
+  _Tp __get(size_t __index) const noexcept { return __storage_[__index]; };
+  void __set(size_t __index, _Tp __val) noexcept {
+    __storage_[__index] = __val;
+  }
+};
+
+#endif // _LIBCPP_HAS_NO_VECTOR_EXTENSION
+
+template <class _Vp, class _Tp, class _Abi>
+class __simd_reference {
+  static_assert(std::is_same<_Vp, _Tp>::value, "");
+
+  template <class, class>
+  friend struct simd;
+
+  template <class, class>
+  friend struct simd_mask;
+
+  __simd_storage<_Tp, _Abi>* __ptr_;
+  size_t __index_;
+
+  __simd_reference(__simd_storage<_Tp, _Abi>* __ptr, size_t __index)
+      : __ptr_(__ptr), __index_(__index) {}
+
+  __simd_reference(const __simd_reference&) = default;
+
+public:
+  __simd_reference() = delete;
+  __simd_reference& operator=(const __simd_reference&) = delete;
+
+  operator _Vp() const { return __ptr_->__get(__index_); }
+
+  __simd_reference operator=(_Vp __value) && {
+    __ptr_->__set(__index_, __value);
+    return *this;
+  }
+
+  __simd_reference operator++() && {
+    return std::move(*this) = __ptr_->__get(__index_) + 1;
+  }
+
+  _Vp operator++(int) && {
+    auto __val = __ptr_->__get(__index_);
+    __ptr_->__set(__index_, __val + 1);
+    return __val;
+  }
+
+  __simd_reference operator--() && {
+    return std::move(*this) = __ptr_->__get(__index_) - 1;
+  }
+
+  _Vp operator--(int) && {
+    auto __val = __ptr_->__get(__index_);
+    __ptr_->__set(__index_, __val - 1);
+    return __val;
+  }
+
+  __simd_reference operator+=(_Vp __value) && {
+    return std::move(*this) = __ptr_->__get(__index_) + __value;
+  }
+
+  __simd_reference operator-=(_Vp __value) && {
+    return std::move(*this) = __ptr_->__get(__index_) - __value;
+  }
+
+  __simd_reference operator*=(_Vp __value) && {
+    return std::move(*this) = __ptr_->__get(__index_) * __value;
+  }
+
+  __simd_reference operator/=(_Vp __value) && {
+    return std::move(*this) = __ptr_->__get(__index_) / __value;
+  }
+
+  __simd_reference operator%=(_Vp __value) && {
+    return std::move(*this) = __ptr_->__get(__index_) % __value;
+  }
+
+  __simd_reference operator>>=(_Vp __value) && {
+    return std::move(*this) = __ptr_->__get(__index_) >> __value;
+  }
+
+  __simd_reference operator<<=(_Vp __value) && {
+    return std::move(*this) = __ptr_->__get(__index_) << __value;
+  }
+
+  __simd_reference operator&=(_Vp __value) && {
+    return std::move(*this) = __ptr_->__get(__index_) & __value;
+  }
+
+  __simd_reference operator|=(_Vp __value) && {
+    return std::move(*this) = __ptr_->__get(__index_) | __value;
+  }
+
+  __simd_reference operator^=(_Vp __value) && {
+    return std::move(*this) = __ptr_->__get(__index_) ^ __value;
+  }
+};
+
+template <class _To, class _From>
+constexpr decltype(_To{std::declval<_From>()}, true)
+__is_non_narrowing_convertible_impl(_From) {
+  return true;
+}
+
+template <class _To>
+constexpr bool __is_non_narrowing_convertible_impl(...) {
+  return false;
+}
+
+template <class _From, class _To>
+constexpr typename std::enable_if<std::is_arithmetic<_To>::value &&
+                                      std::is_arithmetic<_From>::value,
+                                  bool>::type
+__is_non_narrowing_arithmetic_convertible() {
+  return __is_non_narrowing_convertible_impl<_To>(_From{});
+}
+
+template <class _From, class _To>
+constexpr typename std::enable_if<!(std::is_arithmetic<_To>::value &&
+                                    std::is_arithmetic<_From>::value),
+                                  bool>::type
+__is_non_narrowing_arithmetic_convertible() {
+  return false;
+}
+
+template <class _Tp>
+constexpr _Tp __variadic_sum() {
+  return _Tp{};
+}
+
+template <class _Tp, class _Up, class... _Args>
+constexpr _Tp __variadic_sum(_Up __first, _Args... __rest) {
+  return static_cast<_Tp>(__first) + __variadic_sum<_Tp>(__rest...);
+}
+
+template <class _Tp>
+struct __nodeduce {
+  using type = _Tp;
+};
+
+template <class _Tp>
+constexpr bool __vectorizable() {
+  return std::is_arithmetic<_Tp>::value && !std::is_const<_Tp>::value &&
+         !std::is_volatile<_Tp>::value && !std::is_same<_Tp, bool>::value;
+}
+
+_LIBCPP_END_NAMESPACE_EXPERIMENTAL_SIMD
+_LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_SIMD_ABI
+
+using scalar = __simd_abi<_StorageKind::_Scalar, 1>;
+
+template <int _Np>
+using fixed_size = __simd_abi<_StorageKind::_Array, _Np>;
+
+template <class _Tp>
+inline constexpr size_t max_fixed_size = 32;
+
+template <class _Tp>
+using compatible = fixed_size<16 / sizeof(_Tp)>;
+
+#ifndef _LIBCPP_HAS_NO_VECTOR_EXTENSION
+template <class _Tp>
+using native = __simd_abi<_StorageKind::_VecExt,
+                          _LIBCPP_NATIVE_SIMD_WIDTH_IN_BYTES / sizeof(_Tp)>;
+#else
+template <class _Tp>
+using native =
+    fixed_size<_Tp, _LIBCPP_NATIVE_SIMD_WIDTH_IN_BYTES / sizeof(_Tp)>;
+#endif // _LIBCPP_HAS_NO_VECTOR_EXTENSION
+
+_LIBCPP_END_NAMESPACE_EXPERIMENTAL_SIMD_ABI
+_LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL_SIMD
+
+template <class _Tp, class _Abi = simd_abi::compatible<_Tp>>
+class simd;
+template <class _Tp, class _Abi = simd_abi::compatible<_Tp>>
+class simd_mask;
+
+struct element_aligned_tag {};
+struct vector_aligned_tag {};
+template <size_t>
+struct overaligned_tag {};
+inline constexpr element_aligned_tag element_aligned{};
+inline constexpr vector_aligned_tag vector_aligned{};
+template <size_t _Np>
+inline constexpr overaligned_tag<_Np> overaligned{};
+
+// traits [simd.traits]
+template <class _Tp>
+struct is_abi_tag : std::integral_constant<bool, false> {};
+
+template <_StorageKind __kind, int _Np>
+struct is_abi_tag<__simd_abi<__kind, _Np>>
+    : std::integral_constant<bool, true> {};
+
+template <class _Tp>
+struct is_simd : std::integral_constant<bool, false> {};
+
+template <class _Tp, class _Abi>
+struct is_simd<simd<_Tp, _Abi>> : std::integral_constant<bool, true> {};
+
+template <class _Tp>
+struct is_simd_mask : std::integral_constant<bool, false> {};
+
+template <class _Tp, class _Abi>
+struct is_simd_mask<simd_mask<_Tp, _Abi>> : std::integral_constant<bool, true> {
+};
+
+template <class _Tp>
+struct is_simd_flag_type : std::integral_constant<bool, false> {};
+
+template <>
+struct is_simd_flag_type<element_aligned_tag>
+    : std::integral_constant<bool, true> {};
+
+template <>
+struct is_simd_flag_type<vector_aligned_tag>
+    : std::integral_constant<bool, true> {};
+
+template <size_t _Align>
+struct is_simd_flag_type<overaligned_tag<_Align>>
+    : std::integral_constant<bool, true> {};
+
+template <class _Tp>
+inline constexpr bool is_abi_tag_v = is_abi_tag<_Tp>::value;
+template <class _Tp>
+inline constexpr bool is_simd_v = is_simd<_Tp>::value;
+template <class _Tp>
+inline constexpr bool is_simd_mask_v = is_simd_mask<_Tp>::value;
+template <class _Tp>
+inline constexpr bool is_simd_flag_type_v = is_simd_flag_type<_Tp>::value;
+template <class _Tp, size_t _Np>
+struct abi_for_size {
+  using type = simd_abi::fixed_size<_Np>;
+};
+template <class _Tp, size_t _Np>
+using abi_for_size_t = typename abi_for_size<_Tp, _Np>::type;
+
+template <class _Tp, class _Abi = simd_abi::compatible<_Tp>>
+struct simd_size;
+
+template <class _Tp, _StorageKind __kind, int _Np>
+struct simd_size<_Tp, __simd_abi<__kind, _Np>>
+    : std::integral_constant<size_t, _Np> {
+  static_assert(
+      std::is_arithmetic<_Tp>::value &&
+          !std::is_same<typename std::remove_const<_Tp>::type, bool>::value,
+      "Element type should be vectorizable");
+};
+
+// TODO: implement it.
+template <class _Tp, class _Up = typename _Tp::value_type>
+struct memory_alignment;
+
+template <class _Tp, class _Abi = simd_abi::compatible<_Tp>>
+inline constexpr size_t simd_size_v = simd_size<_Tp, _Abi>::value;
+
+template <class _Tp, class _Up = typename _Tp::value_type>
+inline constexpr size_t memory_alignment_v = memory_alignment<_Tp, _Up>::value;
+
+// class template simd [simd.class]
+template <class _Tp>
+using native_simd = simd<_Tp, simd_abi::native<_Tp>>;
+template <class _Tp, int _Np>
+using fixed_size_simd = simd<_Tp, simd_abi::fixed_size<_Np>>;
+
+// class template simd_mask [simd.mask.class]
+template <class _Tp>
+using native_simd_mask = simd_mask<_Tp, simd_abi::native<_Tp>>;
+
+template <class _Tp, int _Np>
+using fixed_size_simd_mask = simd_mask<_Tp, simd_abi::fixed_size<_Np>>;
+
+// casts [simd.casts]
+template <class _Tp>
+struct __static_simd_cast_traits {
+  template <class _Up, class _Abi>
+  static simd<_Tp, _Abi> __apply(const simd<_Up, _Abi>& __v);
+};
+
+template <class _Tp, class _NewAbi>
+struct __static_simd_cast_traits<simd<_Tp, _NewAbi>> {
+  template <class _Up, class _Abi>
+  static typename std::enable_if<simd<_Up, _Abi>::size() ==
+                                     simd<_Tp, _NewAbi>::size(),
+                                 simd<_Tp, _NewAbi>>::type
+  __apply(const simd<_Up, _Abi>& __v);
+};
+
+template <class _Tp>
+struct __simd_cast_traits {
+  template <class _Up, class _Abi>
+  static typename std::enable_if<
+      __is_non_narrowing_arithmetic_convertible<_Up, _Tp>(),
+      simd<_Tp, _Abi>>::type
+  __apply(const simd<_Up, _Abi>& __v);
+};
+
+template <class _Tp, class _NewAbi>
+struct __simd_cast_traits<simd<_Tp, _NewAbi>> {
+  template <class _Up, class _Abi>
+  static typename std::enable_if<
+      __is_non_narrowing_arithmetic_convertible<_Up, _Tp>() &&
+          simd<_Up, _Abi>::size() == simd<_Tp, _NewAbi>::size(),
+      simd<_Tp, _NewAbi>>::type
+  __apply(const simd<_Up, _Abi>& __v);
+};
+
+template <class _Tp, class _Up, class _Abi>
+auto simd_cast(const simd<_Up, _Abi>& __v)
+    -> decltype(__simd_cast_traits<_Tp>::__apply(__v)) {
+  return __simd_cast_traits<_Tp>::__apply(__v);
+}
+
+template <class _Tp, class _Up, class _Abi>
+auto static_simd_cast(const simd<_Up, _Abi>& __v)
+    -> decltype(__static_simd_cast_traits<_Tp>::__apply(__v)) {
+  return __static_simd_cast_traits<_Tp>::__apply(__v);
+}
+
+template <class _Tp, class _Abi>
+fixed_size_simd<_Tp, simd_size<_Tp, _Abi>::value>
+to_fixed_size(const simd<_Tp, _Abi>&) noexcept;
+
+template <class _Tp, class _Abi>
+fixed_size_simd_mask<_Tp, simd_size<_Tp, _Abi>::value>
+to_fixed_size(const simd_mask<_Tp, _Abi>&) noexcept;
+
+template <class _Tp, size_t _Np>
+native_simd<_Tp> to_native(const fixed_size_simd<_Tp, _Np>&) noexcept;
+
+template <class _Tp, size_t _Np>
+native_simd_mask<_Tp> to_native(const fixed_size_simd_mask<_Tp, _Np>&) noexcept;
+
+template <class _Tp, size_t _Np>
+simd<_Tp> to_compatible(const fixed_size_simd<_Tp, _Np>&) noexcept;
+
+template <class _Tp, size_t _Np>
+simd_mask<_Tp> to_compatible(const fixed_size_simd_mask<_Tp, _Np>&) noexcept;
+
+template <size_t... __sizes, class _Tp, class _Abi>
+tuple<simd<_Tp, abi_for_size_t<_Tp, __sizes>>...> split(const simd<_Tp, _Abi>&);
+
+template <size_t... __sizes, class _Tp, class _Abi>
+tuple<simd_mask<_Tp, abi_for_size_t<_Tp, __sizes>>...>
+split(const simd_mask<_Tp, _Abi>&);
+
+template <class _SimdType, class _Abi>
+array<_SimdType, simd_size<typename _SimdType::value_type, _Abi>::value /
+                     _SimdType::size()>
+split(const simd<typename _SimdType::value_type, _Abi>&);
+
+template <class _SimdType, class _Abi>
+array<_SimdType, simd_size<typename _SimdType::value_type, _Abi>::value /
+                     _SimdType::size()>
+split(const simd_mask<typename _SimdType::value_type, _Abi>&);
+
+template <class _Tp, class... _Abis>
+simd<_Tp, abi_for_size_t<_Tp, __variadic_sum(simd_size<_Tp, _Abis>::value...)>>
+concat(const simd<_Tp, _Abis>&...);
+
+template <class _Tp, class... _Abis>
+simd_mask<_Tp,
+          abi_for_size_t<_Tp, __variadic_sum(simd_size<_Tp, _Abis>::value...)>>
+concat(const simd_mask<_Tp, _Abis>&...);
+
+// reductions [simd.mask.reductions]
+template <class _Tp, class _Abi>
+bool all_of(const simd_mask<_Tp, _Abi>&) noexcept;
+template <class _Tp, class _Abi>
+bool any_of(const simd_mask<_Tp, _Abi>&) noexcept;
+template <class _Tp, class _Abi>
+bool none_of(const simd_mask<_Tp, _Abi>&) noexcept;
+template <class _Tp, class _Abi>
+bool some_of(const simd_mask<_Tp, _Abi>&) noexcept;
+template <class _Tp, class _Abi>
+int popcount(const simd_mask<_Tp, _Abi>&) noexcept;
+template <class _Tp, class _Abi>
+int find_first_set(const simd_mask<_Tp, _Abi>&);
+template <class _Tp, class _Abi>
+int find_last_set(const simd_mask<_Tp, _Abi>&);
+bool all_of(bool) noexcept;
+bool any_of(bool) noexcept;
+bool none_of(bool) noexcept;
+bool some_of(bool) noexcept;
+int popcount(bool) noexcept;
+int find_first_set(bool) noexcept;
+int find_last_set(bool) noexcept;
+
+// masked assignment [simd.whereexpr]
+template <class _MaskType, class _Tp>
+class const_where_expression;
+template <class _MaskType, class _Tp>
+class where_expression;
+
+// masked assignment [simd.mask.where]
+template <class _Tp, class _Abi>
+where_expression<simd_mask<_Tp, _Abi>, simd<_Tp, _Abi>>
+where(const typename simd<_Tp, _Abi>::mask_type&, simd<_Tp, _Abi>&) noexcept;
+
+template <class _Tp, class _Abi>
+const_where_expression<simd_mask<_Tp, _Abi>, const simd<_Tp, _Abi>>
+where(const typename simd<_Tp, _Abi>::mask_type&,
+      const simd<_Tp, _Abi>&) noexcept;
+
+template <class _Tp, class _Abi>
+where_expression<simd_mask<_Tp, _Abi>, simd_mask<_Tp, _Abi>>
+where(const typename __nodeduce<simd_mask<_Tp, _Abi>>::type&,
+      simd_mask<_Tp, _Abi>&) noexcept;
+
+template <class _Tp, class _Abi>
+const_where_expression<simd_mask<_Tp, _Abi>, const simd_mask<_Tp, _Abi>>
+where(const typename __nodeduce<simd_mask<_Tp, _Abi>>::type&,
+      const simd_mask<_Tp, _Abi>&) noexcept;
+
+template <class _Tp>
+where_expression<bool, _Tp> where(bool, _Tp&) noexcept;
+
+template <class _Tp>
+const_where_expression<bool, const _Tp> where(bool, const _Tp&) noexcept;
+
+// reductions [simd.reductions]
+template <class _Tp, class _Abi, class _BinaryOp = std::plus<_Tp>>
+_Tp reduce(const simd<_Tp, _Abi>&, _BinaryOp = _BinaryOp());
+
+template <class _MaskType, class _SimdType, class _BinaryOp>
+typename _SimdType::value_type
+reduce(const const_where_expression<_MaskType, _SimdType>&,
+       typename _SimdType::value_type neutral_element, _BinaryOp binary_op);
+
+template <class _MaskType, class _SimdType>
+typename _SimdType::value_type
+reduce(const const_where_expression<_MaskType, _SimdType>&,
+       plus<typename _SimdType::value_type> binary_op = {});
+
+template <class _MaskType, class _SimdType>
+typename _SimdType::value_type
+reduce(const const_where_expression<_MaskType, _SimdType>&,
+       multiplies<typename _SimdType::value_type> binary_op);
+
+template <class _MaskType, class _SimdType>
+typename _SimdType::value_type
+reduce(const const_where_expression<_MaskType, _SimdType>&,
+       bit_and<typename _SimdType::value_type> binary_op);
+
+template <class _MaskType, class _SimdType>
+typename _SimdType::value_type
+reduce(const const_where_expression<_MaskType, _SimdType>&,
+       bit_or<typename _SimdType::value_type> binary_op);
+
+template <class _MaskType, class _SimdType>
+typename _SimdType::value_type
+reduce(const const_where_expression<_MaskType, _SimdType>&,
+       bit_xor<typename _SimdType::value_type> binary_op);
+
+template <class _Tp, class _Abi>
+_Tp hmin(const simd<_Tp, _Abi>&);
+template <class _MaskType, class _SimdType>
+typename _SimdType::value_type
+hmin(const const_where_expression<_MaskType, _SimdType>&);
+template <class _Tp, class _Abi>
+_Tp hmax(const simd<_Tp, _Abi>&);
+template <class _MaskType, class _SimdType>
+typename _SimdType::value_type
+hmax(const const_where_expression<_MaskType, _SimdType>&);
+
+// algorithms [simd.alg]
+template <class _Tp, class _Abi>
+simd<_Tp, _Abi> min(const simd<_Tp, _Abi>&, const simd<_Tp, _Abi>&) noexcept;
+
+template <class _Tp, class _Abi>
+simd<_Tp, _Abi> max(const simd<_Tp, _Abi>&, const simd<_Tp, _Abi>&) noexcept;
+
+template <class _Tp, class _Abi>
+std::pair<simd<_Tp, _Abi>, simd<_Tp, _Abi>>
+minmax(const simd<_Tp, _Abi>&, const simd<_Tp, _Abi>&) noexcept;
+
+template <class _Tp, class _Abi>
+simd<_Tp, _Abi> clamp(const simd<_Tp, _Abi>&, const simd<_Tp, _Abi>&,
+                      const simd<_Tp, _Abi>&);
+
+// [simd.whereexpr]
+// TODO implement where expressions.
+template <class _MaskType, class _Tp>
+class const_where_expression {
+public:
+  const_where_expression(const const_where_expression&) = delete;
+  const_where_expression& operator=(const const_where_expression&) = delete;
+  typename remove_const<_Tp>::type operator-() const&&;
+  template <class _Up, class _Flags>
+  void copy_to(_Up*, _Flags) const&&;
+};
+
+template <class _MaskType, class _Tp>
+class where_expression : public const_where_expression<_MaskType, _Tp> {
+public:
+  where_expression(const where_expression&) = delete;
+  where_expression& operator=(const where_expression&) = delete;
+  template <class _Up>
+  void operator=(_Up&&);
+  template <class _Up>
+  void operator+=(_Up&&);
+  template <class _Up>
+  void operator-=(_Up&&);
+  template <class _Up>
+  void operator*=(_Up&&);
+  template <class _Up>
+  void operator/=(_Up&&);
+  template <class _Up>
+  void operator%=(_Up&&);
+  template <class _Up>
+  void operator&=(_Up&&);
+  template <class _Up>
+  void operator|=(_Up&&);
+  template <class _Up>
+  void operator^=(_Up&&);
+  template <class _Up>
+  void operator<<=(_Up&&);
+  template <class _Up>
+  void operator>>=(_Up&&);
+  void operator++();
+  void operator++(int);
+  void operator--();
+  void operator--(int);
+  template <class _Up, class _Flags>
+  void copy_from(const _Up*, _Flags);
+};
+
+// [simd.class]
+// TODO: implement simd
+template <class _Tp, class _Abi>
+class simd {
+public:
+  using value_type = _Tp;
+  using reference = __simd_reference<_Tp, _Tp, _Abi>;
+  using mask_type = simd_mask<_Tp, _Abi>;
+  using abi_type = _Abi;
+
+  simd() = default;
+  simd(const simd&) = default;
+  simd& operator=(const simd&) = default;
+
+  static constexpr size_t size() noexcept {
+    return simd_size<_Tp, _Abi>::value;
+  }
+
+private:
+  __simd_storage<_Tp, _Abi> __s_;
+
+  template <class _Up>
+  static constexpr bool __can_broadcast() {
+    return (std::is_arithmetic<_Up>::value &&
+            __is_non_narrowing_arithmetic_convertible<_Up, _Tp>()) ||
+           (!std::is_arithmetic<_Up>::value &&
+            std::is_convertible<_Up, _Tp>::value) ||
+           std::is_same<typename std::remove_const<_Up>::type, int>::value ||
+           (std::is_same<typename std::remove_const<_Up>::type,
+                         unsigned int>::value &&
+            std::is_unsigned<_Tp>::value);
+  }
+
+  template <class _Generator, size_t... __indicies>
+  static constexpr decltype(
+      std::forward_as_tuple(std::declval<_Generator>()(
+          std::integral_constant<size_t, __indicies>())...),
+      bool())
+  __can_generate(std::index_sequence<__indicies...>) {
+    return !__variadic_sum<bool>(
+        !__can_broadcast<decltype(std::declval<_Generator>()(
+            std::integral_constant<size_t, __indicies>()))>()...);
+  }
+
+  template <class _Generator>
+  static bool __can_generate(...) {
+    return false;
+  }
+
+  template <class _Generator, size_t... __indicies>
+  void __generator_init(_Generator&& __g, std::index_sequence<__indicies...>) {
+    int __not_used[]{((*this)[__indicies] =
+                          __g(std::integral_constant<size_t, __indicies>()),
+                      0)...};
+    (void)__not_used;
+  }
+
+public:
+  // implicit type conversion constructor
+  template <class _Up,
+            class = typename std::enable_if<
+                std::is_same<_Abi, simd_abi::fixed_size<size()>>::value &&
+                __is_non_narrowing_arithmetic_convertible<_Up, _Tp>()>::type>
+  simd(const simd<_Up, simd_abi::fixed_size<size()>>& __v) {
+    for (size_t __i = 0; __i < size(); __i++) {
+      (*this)[__i] = static_cast<_Tp>(__v[__i]);
+    }
+  }
+
+  // implicit broadcast constructor
+  template <class _Up,
+            class = typename std::enable_if<__can_broadcast<_Up>()>::type>
+  simd(_Up&& __rv) {
+    auto __v = static_cast<_Tp>(__rv);
+    for (size_t __i = 0; __i < size(); __i++) {
+      (*this)[__i] = __v;
+    }
+  }
+
+  // generator constructor
+  template <class _Generator,
+            int = typename std::enable_if<
+                __can_generate<_Generator>(std::make_index_sequence<size()>()),
+                int>::type()>
+  explicit simd(_Generator&& __g) {
+    __generator_init(std::forward<_Generator>(__g),
+                     std::make_index_sequence<size()>());
+  }
+
+  // load constructor
+  template <
+      class _Up, class _Flags,
+      class = typename std::enable_if<__vectorizable<_Up>()>::type,
+      class = typename std::enable_if<is_simd_flag_type<_Flags>::value>::type>
+  simd(const _Up* __buffer, _Flags) {
+    // TODO: optimize for overaligned flags
+    for (size_t __i = 0; __i < size(); __i++) {
+      (*this)[__i] = static_cast<_Tp>(__buffer[__i]);
+    }
+  }
+
+  // loads [simd.load]
+  template <class _Up, class _Flags>
+  typename std::enable_if<__vectorizable<_Up>() &&
+                          is_simd_flag_type<_Flags>::value>::type
+  copy_from(const _Up* __buffer, _Flags) {
+    *this = simd(__buffer, _Flags());
+  }
+
+  // stores [simd.store]
+  template <class _Up, class _Flags>
+  typename std::enable_if<__vectorizable<_Up>() &&
+                          is_simd_flag_type<_Flags>::value>::type
+  copy_to(_Up* __buffer, _Flags) const {
+    // TODO: optimize for overaligned flags
+    for (size_t __i = 0; __i < size(); __i++) {
+      __buffer[__i] = static_cast<_Up>((*this)[__i]);
+    }
+  }
+
+  // scalar access [simd.subscr]
+  reference operator[](size_t __i) { return reference(&__s_, __i); }
+
+  value_type operator[](size_t __i) const { return __s_.__get(__i); }
+
+  // unary operators [simd.unary]
+  simd& operator++();
+  simd operator++(int);
+  simd& operator--();
+  simd operator--(int);
+  mask_type operator!() const;
+  simd operator~() const;
+  simd operator+() const;
+  simd operator-() const;
+
+  // binary operators [simd.binary]
+  friend simd operator+(const simd&, const simd&);
+  friend simd operator-(const simd&, const simd&);
+  friend simd operator*(const simd&, const simd&);
+  friend simd operator/(const simd&, const simd&);
+  friend simd operator%(const simd&, const simd&);
+  friend simd operator&(const simd&, const simd&);
+  friend simd operator|(const simd&, const simd&);
+  friend simd operator^(const simd&, const simd&);
+  friend simd operator<<(const simd&, const simd&);
+  friend simd operator>>(const simd&, const simd&);
+  friend simd operator<<(const simd&, int);
+  friend simd operator>>(const simd&, int);
+
+  // compound assignment [simd.cassign]
+  friend simd& operator+=(simd&, const simd&);
+  friend simd& operator-=(simd&, const simd&);
+  friend simd& operator*=(simd&, const simd&);
+  friend simd& operator/=(simd&, const simd&);
+  friend simd& operator%=(simd&, const simd&);
+
+  friend simd& operator&=(simd&, const simd&);
+  friend simd& operator|=(simd&, const simd&);
+  friend simd& operator^=(simd&, const simd&);
+  friend simd& operator<<=(simd&, const simd&);
+  friend simd& operator>>=(simd&, const simd&);
+  friend simd& operator<<=(simd&, int);
+  friend simd& operator>>=(simd&, int);
+
+  // compares [simd.comparison]
+  friend mask_type operator==(const simd&, const simd&);
+  friend mask_type operator!=(const simd&, const simd&);
+  friend mask_type operator>=(const simd&, const simd&);
+  friend mask_type operator<=(const simd&, const simd&);
+  friend mask_type operator>(const simd&, const simd&);
+  friend mask_type operator<(const simd&, const simd&);
+};
+
+// [simd.mask.class]
+template <class _Tp, class _Abi>
+// TODO: implement simd_mask
+class simd_mask {
+public:
+  using value_type = bool;
+  // TODO: this is strawman implementation. Turn it into a proxy type.
+  using reference = bool&;
+  using simd_type = simd<_Tp, _Abi>;
+  using abi_type = _Abi;
+  static constexpr size_t size() noexcept;
+  simd_mask() = default;
+
+  // broadcast constructor
+  explicit simd_mask(value_type) noexcept;
+
+  // implicit type conversion constructor
+  template <class _Up>
+  simd_mask(const simd_mask<_Up, simd_abi::fixed_size<size()>>&) noexcept;
+
+  // load constructor
+  template <class _Flags>
+  simd_mask(const value_type*, _Flags);
+
+  // loads [simd.mask.copy]
+  template <class _Flags>
+  void copy_from(const value_type*, _Flags);
+  template <class _Flags>
+  void copy_to(value_type*, _Flags) const;
+
+  // scalar access [simd.mask.subscr]
+  reference operator[](size_t);
+  value_type operator[](size_t) const;
+
+  // unary operators [simd.mask.unary]
+  simd_mask operator!() const noexcept;
+
+  // simd_mask binary operators [simd.mask.binary]
+  friend simd_mask operator&&(const simd_mask&, const simd_mask&) noexcept;
+  friend simd_mask operator||(const simd_mask&, const simd_mask&) noexcept;
+  friend simd_mask operator&(const simd_mask&, const simd_mask&)noexcept;
+  friend simd_mask operator|(const simd_mask&, const simd_mask&) noexcept;
+  friend simd_mask operator^(const simd_mask&, const simd_mask&) noexcept;
+
+  // simd_mask compound assignment [simd.mask.cassign]
+  friend simd_mask& operator&=(simd_mask&, const simd_mask&) noexcept;
+  friend simd_mask& operator|=(simd_mask&, const simd_mask&) noexcept;
+  friend simd_mask& operator^=(simd_mask&, const simd_mask&) noexcept;
+
+  // simd_mask compares [simd.mask.comparison]
+  friend simd_mask operator==(const simd_mask&, const simd_mask&) noexcept;
+  friend simd_mask operator!=(const simd_mask&, const simd_mask&) noexcept;
+};
+
+#endif // _LIBCPP_STD_VER >= 17
+
+_LIBCPP_END_NAMESPACE_EXPERIMENTAL_SIMD
+
+_LIBCPP_POP_MACROS
+
+#endif /* _LIBCPP_EXPERIMENTAL_SIMD */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/string b/contrib/libs/cxxsupp/libcxx/include/experimental/string
new file mode 100644
index 00000000000..63890ac51b0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/string
@@ -0,0 +1,63 @@
+// -*- C++ -*-
+//===--------------------------- string ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_STRING
+#define _LIBCPP_EXPERIMENTAL_STRING
+/*
+    experimental/string synopsis
+
+// C++1z
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+namespace pmr {
+
+  // basic_string using polymorphic allocator in namespace pmr
+  template <class charT, class traits = char_traits<charT>>
+   using basic_string =
+     std::basic_string<charT, traits, polymorphic_allocator<charT>>;
+
+  // basic_string typedef names using polymorphic allocator in namespace
+  // std::experimental::pmr
+  typedef basic_string<char> string;
+  typedef basic_string<char16_t> u16string;
+  typedef basic_string<char32_t> u32string;
+  typedef basic_string<wchar_t> wstring;
+
+} // namespace pmr
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <string>
+#include <experimental/memory_resource>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+template <class _CharT, class _Traits = char_traits<_CharT>>
+using basic_string =
+    _VSTD::basic_string<_CharT, _Traits, polymorphic_allocator<_CharT>>;
+
+typedef basic_string<char> string;
+typedef basic_string<char16_t> u16string;
+typedef basic_string<char32_t> u32string;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef basic_string<wchar_t> wstring;
+#endif
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR
+
+#endif /* _LIBCPP_EXPERIMENTAL_STRING */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/type_traits b/contrib/libs/cxxsupp/libcxx/include/experimental/type_traits
new file mode 100644
index 00000000000..ea1335f96af
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/type_traits
@@ -0,0 +1,154 @@
+// -*- C++ -*-
+//===-------------------------- type_traits -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_TYPE_TRAITS
+#define _LIBCPP_EXPERIMENTAL_TYPE_TRAITS
+
+/**
+    experimental/type_traits synopsis
+
+// C++1y
+#include <type_traits>
+
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+
+  // 3.3.2, Other type transformations
+  template <class> class invocation_type; // not defined
+  template <class F, class... ArgTypes> class invocation_type<F(ArgTypes...)>;
+  template <class> class raw_invocation_type; // not defined
+  template <class F, class... ArgTypes> class raw_invocation_type<F(ArgTypes...)>;
+
+  template <class T>
+    using invocation_type_t = typename invocation_type<T>::type;
+  template <class T>
+    using raw_invocation_type_t = typename raw_invocation_type<T>::type;
+
+  // 3.3.4, Detection idiom
+  template <class...> using void_t = void;
+
+  struct nonesuch {
+    nonesuch() = delete;
+    ~nonesuch() = delete;
+    nonesuch(nonesuch const&) = delete;
+    void operator=(nonesuch const&) = delete;
+  };
+
+  template <template<class...> class Op, class... Args>
+    using is_detected = see below;
+  template <template<class...> class Op, class... Args>
+    constexpr bool is_detected_v = is_detected<Op, Args...>::value;
+  template <template<class...> class Op, class... Args>
+    using detected_t = see below;
+  template <class Default, template<class...> class Op, class... Args>
+    using detected_or = see below;
+  template <class Default, template<class...> class Op, class... Args>
+    using detected_or_t = typename detected_or<Default, Op, Args...>::type;
+  template <class Expected, template<class...> class Op, class... Args>
+    using is_detected_exact = is_same<Expected, detected_t<Op, Args...>>;
+  template <class Expected, template<class...> class Op, class... Args>
+    constexpr bool is_detected_exact_v
+      = is_detected_exact<Expected, Op, Args...>::value;
+  template <class To, template<class...> class Op, class... Args>
+     using is_detected_convertible = is_convertible<detected_t<Op, Args...>, To>;
+  template <class To, template<class...> class Op, class... Args>
+     constexpr bool is_detected_convertible_v
+       = is_detected_convertible<To, Op, Args...>::value;
+
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+
+#if _LIBCPP_STD_VER > 11
+
+#include <initializer_list>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS
+
+// 3.3.2, Other type transformations
+/*
+template <class>
+class _LIBCPP_TEMPLATE_VIS raw_invocation_type;
+
+template <class _Fn, class ..._Args>
+class _LIBCPP_TEMPLATE_VIS raw_invocation_type<_Fn(_Args...)>;
+
+template <class>
+class _LIBCPP_TEMPLATE_VIS invokation_type;
+
+template <class _Fn, class ..._Args>
+class _LIBCPP_TEMPLATE_VIS invokation_type<_Fn(_Args...)>;
+
+template <class _Tp>
+using invokation_type_t = typename invokation_type<_Tp>::type;
+
+template <class _Tp>
+using raw_invocation_type_t = typename raw_invocation_type<_Tp>::type;
+*/
+
+// 3.3.4, Detection idiom
+template <class...> using void_t = void;
+
+struct nonesuch : private __nat { // make nonesuch "not an aggregate"
+  ~nonesuch() = delete;
+  nonesuch      (nonesuch const&) = delete;
+  void operator=(nonesuch const&) = delete;
+  };
+
+template <class _Default, class _AlwaysVoid, template <class...> class _Op, class... _Args>
+struct _DETECTOR {
+   using value_t = false_type;
+   using type = _Default;
+   };
+
+template <class _Default, template <class...> class _Op, class... _Args>
+struct _DETECTOR<_Default, void_t<_Op<_Args...>>, _Op, _Args...> {
+   using value_t = true_type;
+   using type = _Op<_Args...>;
+   };
+
+
+template <template<class...> class _Op, class... _Args>
+  using is_detected = typename _DETECTOR<nonesuch, void, _Op, _Args...>::value_t;
+template <template<class...> class _Op, class... _Args>
+  using detected_t = typename _DETECTOR<nonesuch, void, _Op, _Args...>::type;
+template <template<class...> class _Op, class... _Args>
+  _LIBCPP_CONSTEXPR bool is_detected_v = is_detected<_Op, _Args...>::value;
+
+template <class Default, template<class...> class _Op, class... _Args>
+  using detected_or = _DETECTOR<Default, void, _Op, _Args...>;
+template <class Default, template<class...> class _Op, class... _Args>
+  using detected_or_t = typename detected_or<Default, _Op, _Args...>::type;
+
+template <class Expected, template<class...> class _Op, class... _Args>
+  using is_detected_exact = is_same<Expected, detected_t<_Op, _Args...>>;
+template <class Expected, template<class...> class _Op, class... _Args>
+  _LIBCPP_CONSTEXPR bool is_detected_exact_v = is_detected_exact<Expected, _Op, _Args...>::value;
+
+template <class To, template<class...> class _Op, class... _Args>
+  using is_detected_convertible = is_convertible<detected_t<_Op, _Args...>, To>;
+template <class To, template<class...> class _Op, class... _Args>
+  _LIBCPP_CONSTEXPR bool is_detected_convertible_v = is_detected_convertible<To, _Op, _Args...>::value;
+
+
+_LIBCPP_END_NAMESPACE_LFTS
+
+#endif /* _LIBCPP_STD_VER > 11 */
+
+#endif /* _LIBCPP_EXPERIMENTAL_TYPE_TRAITS */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/unordered_map b/contrib/libs/cxxsupp/libcxx/include/experimental/unordered_map
new file mode 100644
index 00000000000..eca9cea793a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/unordered_map
@@ -0,0 +1,64 @@
+// -*- C++ -*-
+//===------------------------- unordered_map ------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_UNORDERED_MAP
+#define _LIBCPP_EXPERIMENTAL_UNORDERED_MAP
+/*
+    experimental/unordered_map synopsis
+
+// C++1z
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+namespace pmr {
+
+  template <class Key, class T,
+            class Hash = hash<Key>,
+            class Pred = equal_to<Key>>
+  using unordered_map =
+    std::unordered_map<Key, T, Hash, Pred,
+                       polymorphic_allocator<pair<const Key,T>>>;
+
+  template <class Key, class T,
+            class Hash = hash<Key>,
+            class Pred = equal_to<Key>>
+  using unordered_multimap =
+    std::unordered_multimap<Key, T, Hash, Pred,
+                            polymorphic_allocator<pair<const Key,T>>>;
+
+} // namespace pmr
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <unordered_map>
+#include <experimental/memory_resource>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+template <class _Key, class _Value,
+          class _Hash = hash<_Key>, class _Pred = equal_to<_Key>>
+using unordered_map = _VSTD::unordered_map<_Key, _Value, _Hash, _Pred,
+                        polymorphic_allocator<pair<const _Key, _Value>>>;
+
+template <class _Key, class _Value,
+          class _Hash = hash<_Key>, class _Pred = equal_to<_Key>>
+using unordered_multimap = _VSTD::unordered_multimap<_Key, _Value, _Hash, _Pred,
+                        polymorphic_allocator<pair<const _Key, _Value>>>;
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR
+
+#endif /* _LIBCPP_EXPERIMENTAL_UNORDERED_MAP */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/unordered_set b/contrib/libs/cxxsupp/libcxx/include/experimental/unordered_set
new file mode 100644
index 00000000000..323868f785a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/unordered_set
@@ -0,0 +1,58 @@
+// -*- C++ -*-
+//===------------------------- unordered_set ------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_UNORDERED_SET
+#define _LIBCPP_EXPERIMENTAL_UNORDERED_SET
+/*
+    experimental/unordered_set synopsis
+
+// C++1z
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+namespace pmr {
+
+  template <class T, class Hash = hash<T>, class Pred = equal_to<T>>
+  using unordered_set = std::unordered_set<T, Hash, Pred,
+                       polymorphic_allocator<T>>;
+
+  template <class T, class Hash = hash<T>, class Pred = equal_to<T>>
+  using unordered_multiset = std::unordered_multiset<T, Hash, Pred,
+                       polymorphic_allocator<T>>;
+
+} // namespace pmr
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <unordered_set>
+#include <experimental/memory_resource>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+template <class _Value,
+          class _Hash = hash<_Value>, class _Pred = equal_to<_Value>>
+using unordered_set = _VSTD::unordered_set<_Value, _Hash, _Pred,
+                        polymorphic_allocator<_Value>>;
+
+template <class _Value,
+          class _Hash = hash<_Value>, class _Pred = equal_to<_Value>>
+using unordered_multiset = _VSTD::unordered_multiset<_Value, _Hash, _Pred,
+                        polymorphic_allocator<_Value>>;
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR
+
+#endif /* _LIBCPP_EXPERIMENTAL_UNORDERED_SET */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/utility b/contrib/libs/cxxsupp/libcxx/include/experimental/utility
new file mode 100644
index 00000000000..0bca0f7c9c4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/utility
@@ -0,0 +1,46 @@
+// -*- C++ -*-
+//===-------------------------- utility ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_UTILITY
+#define _LIBCPP_EXPERIMENTAL_UTILITY
+
+/*
+    experimental/utility synopsis
+
+// C++1y
+
+#include <utility>
+
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+
+  3.1.2, erased-type placeholder
+  struct erased_type { };
+
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <utility>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS
+
+  struct _LIBCPP_TEMPLATE_VIS erased_type { };
+
+_LIBCPP_END_NAMESPACE_LFTS
+
+#endif /* _LIBCPP_EXPERIMENTAL_UTILITY */
diff --git a/contrib/libs/cxxsupp/libcxx/include/experimental/vector b/contrib/libs/cxxsupp/libcxx/include/experimental/vector
new file mode 100644
index 00000000000..9b810120695
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/experimental/vector
@@ -0,0 +1,46 @@
+// -*- C++ -*-
+//===--------------------------- vector ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXPERIMENTAL_VECTOR
+#define _LIBCPP_EXPERIMENTAL_VECTOR
+/*
+    experimental/vector synopsis
+
+// C++1z
+namespace std {
+namespace experimental {
+inline namespace fundamentals_v1 {
+namespace pmr {
+
+  template <class T>
+  using vector = std::vector<T, polymorphic_allocator<T>>;
+
+} // namespace pmr
+} // namespace fundamentals_v1
+} // namespace experimental
+} // namespace std
+
+ */
+
+#include <experimental/__config>
+#include <vector>
+#include <experimental/memory_resource>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+template <class _ValueT>
+using vector = _VSTD::vector<_ValueT, polymorphic_allocator<_ValueT>>;
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR
+
+#endif /* _LIBCPP_EXPERIMENTAL_VECTOR */
diff --git a/contrib/libs/cxxsupp/libcxx/include/ext/__hash b/contrib/libs/cxxsupp/libcxx/include/ext/__hash
new file mode 100644
index 00000000000..fbeddf03a40
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/ext/__hash
@@ -0,0 +1,134 @@
+// -*- C++ -*-
+//===------------------------- hash_set ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_EXT_HASH
+#define _LIBCPP_EXT_HASH
+
+#pragma GCC system_header
+
+#include <__string>
+#include <string>
+#include <cstring>
+
+namespace __gnu_cxx {
+
+template <typename _Tp> struct _LIBCPP_TEMPLATE_VIS hash { };
+
+template <> struct _LIBCPP_TEMPLATE_VIS hash<const char*>
+ : public std::unary_function<const char*, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const char *__c) const _NOEXCEPT
+    {
+        return std::__do_string_hash(__c, __c + strlen(__c));
+    }
+};
+
+template <> struct _LIBCPP_TEMPLATE_VIS hash<char *>
+ : public std::unary_function<char*, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(char *__c) const _NOEXCEPT
+    {
+        return std::__do_string_hash<const char *>(__c, __c + strlen(__c));
+    }
+};
+
+template <> struct _LIBCPP_TEMPLATE_VIS hash<char>
+ : public std::unary_function<char, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(char __c) const _NOEXCEPT
+    {
+        return __c;
+    }
+};
+
+template <> struct _LIBCPP_TEMPLATE_VIS hash<signed char>
+ : public std::unary_function<signed char, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(signed char __c) const _NOEXCEPT
+    {
+        return __c;
+    }
+};
+
+template <> struct _LIBCPP_TEMPLATE_VIS hash<unsigned char>
+ : public std::unary_function<unsigned char, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(unsigned char __c) const _NOEXCEPT
+    {
+        return __c;
+    }
+};
+
+template <> struct _LIBCPP_TEMPLATE_VIS hash<short>
+ : public std::unary_function<short, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(short __c) const _NOEXCEPT
+    {
+        return __c;
+    }
+};
+
+template <> struct _LIBCPP_TEMPLATE_VIS hash<unsigned short>
+ : public std::unary_function<unsigned short, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(unsigned short __c) const _NOEXCEPT
+    {
+        return __c;
+    }
+};
+
+template <> struct _LIBCPP_TEMPLATE_VIS hash<int>
+    : public std::unary_function<int, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(int __c) const _NOEXCEPT
+    {
+        return __c;
+    }
+};
+
+template <> struct _LIBCPP_TEMPLATE_VIS hash<unsigned int>
+    : public std::unary_function<unsigned int, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(unsigned int __c) const _NOEXCEPT
+    {
+        return __c;
+    }
+};
+
+template <> struct _LIBCPP_TEMPLATE_VIS hash<long>
+    : public std::unary_function<long, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(long __c) const _NOEXCEPT
+    {
+        return __c;
+    }
+};
+
+template <> struct _LIBCPP_TEMPLATE_VIS hash<unsigned long>
+    : public std::unary_function<unsigned long, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(unsigned long __c) const _NOEXCEPT
+    {
+        return __c;
+    }
+};
+}
+
+#endif // _LIBCPP_EXT_HASH
diff --git a/contrib/libs/cxxsupp/libcxx/include/ext/hash_map b/contrib/libs/cxxsupp/libcxx/include/ext/hash_map
new file mode 100644
index 00000000000..60e32b09e3e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/ext/hash_map
@@ -0,0 +1,984 @@
+// -*- C++ -*-
+//===-------------------------- hash_map ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_HASH_MAP
+#define _LIBCPP_HASH_MAP
+
+/*
+
+    hash_map synopsis
+
+namespace __gnu_cxx
+{
+
+template <class Key, class T, class Hash = hash<Key>, class Pred = equal_to<Key>,
+          class Alloc = allocator<pair<const Key, T>>>
+class hash_map
+{
+public:
+    // types
+    typedef Key                                                        key_type;
+    typedef T                                                          mapped_type;
+    typedef Hash                                                       hasher;
+    typedef Pred                                                       key_equal;
+    typedef Alloc                                                      allocator_type;
+    typedef pair<const key_type, mapped_type>                          value_type;
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    typedef typename allocator_traits<allocator_type>::pointer         pointer;
+    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
+    typedef typename allocator_traits<allocator_type>::size_type       size_type;
+    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
+
+    typedef /unspecified/ iterator;
+    typedef /unspecified/ const_iterator;
+
+    hash_map();
+    explicit hash_map(size_type n, const hasher& hf = hasher(),
+                           const key_equal& eql = key_equal(),
+                           const allocator_type& a = allocator_type());
+    template <class InputIterator>
+    hash_map(InputIterator f, InputIterator l);
+    template <class InputIterator>
+    hash_map(InputIterator f, InputIterator l,
+                size_type n, const hasher& hf = hasher(),
+                const key_equal& eql = key_equal(),
+                const allocator_type& a = allocator_type());
+    hash_map(const hash_map&);
+    ~hash_map();
+    hash_map& operator=(const hash_map&);
+
+    allocator_type get_allocator() const;
+
+    bool      empty() const;
+    size_type size() const;
+    size_type max_size() const;
+
+    iterator       begin();
+    iterator       end();
+    const_iterator begin()  const;
+    const_iterator end()    const;
+
+    pair<iterator, bool> insert(const value_type& obj);
+    template <class InputIterator>
+        void insert(InputIterator first, InputIterator last);
+
+    void erase(const_iterator position);
+    size_type erase(const key_type& k);
+    void erase(const_iterator first, const_iterator last);
+    void clear();
+
+    void swap(hash_map&);
+
+    hasher hash_funct() const;
+    key_equal key_eq() const;
+
+    iterator       find(const key_type& k);
+    const_iterator find(const key_type& k) const;
+    size_type count(const key_type& k) const;
+    pair<iterator, iterator>             equal_range(const key_type& k);
+    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
+
+    mapped_type& operator[](const key_type& k);
+
+    size_type bucket_count() const;
+    size_type max_bucket_count() const;
+
+    size_type elems_in_bucket(size_type n) const;
+
+    void resize(size_type n);
+};
+
+template <class Key, class T, class Hash, class Pred, class Alloc>
+    void swap(hash_map<Key, T, Hash, Pred, Alloc>& x,
+              hash_map<Key, T, Hash, Pred, Alloc>& y);
+
+template <class Key, class T, class Hash, class Pred, class Alloc>
+    bool
+    operator==(const hash_map<Key, T, Hash, Pred, Alloc>& x,
+               const hash_map<Key, T, Hash, Pred, Alloc>& y);
+
+template <class Key, class T, class Hash, class Pred, class Alloc>
+    bool
+    operator!=(const hash_map<Key, T, Hash, Pred, Alloc>& x,
+               const hash_map<Key, T, Hash, Pred, Alloc>& y);
+
+template <class Key, class T, class Hash = hash<Key>, class Pred = equal_to<Key>,
+          class Alloc = allocator<pair<const Key, T>>>
+class hash_multimap
+{
+public:
+    // types
+    typedef Key                                                        key_type;
+    typedef T                                                          mapped_type;
+    typedef Hash                                                       hasher;
+    typedef Pred                                                       key_equal;
+    typedef Alloc                                                      allocator_type;
+    typedef pair<const key_type, mapped_type>                          value_type;
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    typedef typename allocator_traits<allocator_type>::pointer         pointer;
+    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
+    typedef typename allocator_traits<allocator_type>::size_type       size_type;
+    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
+
+    typedef /unspecified/ iterator;
+    typedef /unspecified/ const_iterator;
+
+    explicit hash_multimap(size_type n = 193, const hasher& hf = hasher(),
+                           const key_equal& eql = key_equal(),
+                           const allocator_type& a = allocator_type());
+    template <class InputIterator>
+        hash_multimap(InputIterator f, InputIterator l,
+                      size_type n = 193, const hasher& hf = hasher(),
+                      const key_equal& eql = key_equal(),
+                      const allocator_type& a = allocator_type());
+    explicit hash_multimap(const allocator_type&);
+    hash_multimap(const hash_multimap&);
+    ~hash_multimap();
+    hash_multimap& operator=(const hash_multimap&);
+
+    allocator_type get_allocator() const;
+
+    bool      empty() const;
+    size_type size() const;
+    size_type max_size() const;
+
+    iterator       begin();
+    iterator       end();
+    const_iterator begin()  const;
+    const_iterator end()    const;
+
+    iterator insert(const value_type& obj);
+    template <class InputIterator>
+        void insert(InputIterator first, InputIterator last);
+
+    void erase(const_iterator position);
+    size_type erase(const key_type& k);
+    void erase(const_iterator first, const_iterator last);
+    void clear();
+
+    void swap(hash_multimap&);
+
+    hasher hash_funct() const;
+    key_equal key_eq() const;
+
+    iterator       find(const key_type& k);
+    const_iterator find(const key_type& k) const;
+    size_type count(const key_type& k) const;
+    pair<iterator, iterator>             equal_range(const key_type& k);
+    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
+
+    size_type bucket_count() const;
+    size_type max_bucket_count() const;
+
+    size_type elems_in_bucket(size_type n) const;
+
+    void resize(size_type n);
+};
+
+template <class Key, class T, class Hash, class Pred, class Alloc>
+    void swap(hash_multimap<Key, T, Hash, Pred, Alloc>& x,
+              hash_multimap<Key, T, Hash, Pred, Alloc>& y);
+
+template <class Key, class T, class Hash, class Pred, class Alloc>
+    bool
+    operator==(const hash_multimap<Key, T, Hash, Pred, Alloc>& x,
+               const hash_multimap<Key, T, Hash, Pred, Alloc>& y);
+
+template <class Key, class T, class Hash, class Pred, class Alloc>
+    bool
+    operator!=(const hash_multimap<Key, T, Hash, Pred, Alloc>& x,
+               const hash_multimap<Key, T, Hash, Pred, Alloc>& y);
+
+}  // __gnu_cxx
+
+*/
+
+#include <__config>
+#include <__hash_table>
+#include <functional>
+#include <stdexcept>
+#include <type_traits>
+#include <ext/__hash>
+
+#if defined(__DEPRECATED) && __DEPRECATED
+#if defined(_LIBCPP_WARNING)
+    _LIBCPP_WARNING("Use of the header <ext/hash_map> is deprecated.  Migrate to <unordered_map>")
+#else
+#   warning Use of the header <ext/hash_map> is deprecated.  Migrate to <unordered_map>
+#endif
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+namespace __gnu_cxx {
+
+template <class _Tp, class _Hash,
+          bool = std::is_empty<_Hash>::value && !std::__libcpp_is_final<_Hash>::value
+        >
+class __hash_map_hasher
+    : private _Hash
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY __hash_map_hasher() : _Hash() {}
+    _LIBCPP_INLINE_VISIBILITY __hash_map_hasher(const _Hash& __h) : _Hash(__h) {}
+    _LIBCPP_INLINE_VISIBILITY const _Hash& hash_function() const {return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const _Tp& __x) const
+        {return static_cast<const _Hash&>(*this)(__x.first);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const typename _Tp::first_type& __x) const
+        {return static_cast<const _Hash&>(*this)(__x);}
+};
+
+template <class _Tp, class _Hash>
+class __hash_map_hasher<_Tp, _Hash, false>
+{
+    _Hash __hash_;
+public:
+    _LIBCPP_INLINE_VISIBILITY __hash_map_hasher() : __hash_() {}
+    _LIBCPP_INLINE_VISIBILITY __hash_map_hasher(const _Hash& __h) : __hash_(__h) {}
+    _LIBCPP_INLINE_VISIBILITY const _Hash& hash_function() const {return __hash_;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const _Tp& __x) const
+        {return __hash_(__x.first);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const typename _Tp::first_type& __x) const
+        {return __hash_(__x);}
+};
+
+template <class _Tp, class _Pred,
+          bool = std::is_empty<_Pred>::value && !std::__libcpp_is_final<_Pred>::value
+         >
+class __hash_map_equal
+    : private _Pred
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY __hash_map_equal() : _Pred() {}
+    _LIBCPP_INLINE_VISIBILITY __hash_map_equal(const _Pred& __p) : _Pred(__p) {}
+    _LIBCPP_INLINE_VISIBILITY const _Pred& key_eq() const {return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Tp& __x, const _Tp& __y) const
+        {return static_cast<const _Pred&>(*this)(__x.first, __y.first);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const typename _Tp::first_type& __x, const _Tp& __y) const
+        {return static_cast<const _Pred&>(*this)(__x, __y.first);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Tp& __x, const typename _Tp::first_type& __y) const
+        {return static_cast<const _Pred&>(*this)(__x.first, __y);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const typename _Tp::first_type& __x,
+                    const typename _Tp::first_type& __y) const
+        {return static_cast<const _Pred&>(*this)(__x, __y);}
+};
+
+template <class _Tp, class _Pred>
+class __hash_map_equal<_Tp, _Pred, false>
+{
+    _Pred __pred_;
+public:
+    _LIBCPP_INLINE_VISIBILITY __hash_map_equal() : __pred_() {}
+    _LIBCPP_INLINE_VISIBILITY __hash_map_equal(const _Pred& __p) : __pred_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY const _Pred& key_eq() const {return __pred_;}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Tp& __x, const _Tp& __y) const
+        {return __pred_(__x.first, __y.first);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const typename _Tp::first_type& __x, const _Tp& __y) const
+        {return __pred_(__x, __y.first);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Tp& __x, const typename _Tp::first_type& __y) const
+        {return __pred_(__x.first, __y);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const typename _Tp::first_type& __x,
+                    const typename _Tp::first_type& __y) const
+        {return __pred_(__x, __y);}
+};
+
+template <class _Alloc>
+class __hash_map_node_destructor
+{
+    typedef _Alloc                              allocator_type;
+    typedef std::allocator_traits<allocator_type>    __alloc_traits;
+    typedef typename __alloc_traits::value_type::__node_value_type value_type;
+public:
+    typedef typename __alloc_traits::pointer    pointer;
+private:
+    typedef typename value_type::first_type     first_type;
+    typedef typename value_type::second_type    second_type;
+
+    allocator_type& __na_;
+
+public:
+    bool __first_constructed;
+    bool __second_constructed;
+
+    __hash_map_node_destructor(__hash_map_node_destructor const&) = default;
+    __hash_map_node_destructor& operator=(const __hash_map_node_destructor&) = delete;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __hash_map_node_destructor(allocator_type& __na)
+        : __na_(__na),
+          __first_constructed(false),
+          __second_constructed(false)
+        {}
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_node_destructor(std::__hash_node_destructor<allocator_type>&& __x)
+        : __na_(__x.__na_),
+          __first_constructed(__x.__value_constructed),
+          __second_constructed(__x.__value_constructed)
+        {
+            __x.__value_constructed = false;
+        }
+#else  // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_node_destructor(const std::__hash_node_destructor<allocator_type>& __x)
+        : __na_(__x.__na_),
+          __first_constructed(__x.__value_constructed),
+          __second_constructed(__x.__value_constructed)
+        {
+            const_cast<bool&>(__x.__value_constructed) = false;
+        }
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator()(pointer __p)
+    {
+        if (__second_constructed)
+            __alloc_traits::destroy(__na_, _VSTD::addressof(__p->__value_.second));
+        if (__first_constructed)
+            __alloc_traits::destroy(__na_, _VSTD::addressof(__p->__value_.first));
+        if (__p)
+            __alloc_traits::deallocate(__na_, __p, 1);
+    }
+};
+
+template <class _HashIterator>
+class _LIBCPP_TEMPLATE_VIS __hash_map_iterator
+{
+    _HashIterator __i_;
+
+    typedef const typename _HashIterator::value_type::first_type key_type;
+    typedef typename _HashIterator::value_type::second_type      mapped_type;
+public:
+    typedef std::forward_iterator_tag                            iterator_category;
+    typedef std::pair<key_type, mapped_type>                     value_type;
+    typedef typename _HashIterator::difference_type              difference_type;
+    typedef value_type&                                          reference;
+    typedef typename std::__rebind_pointer<typename _HashIterator::pointer, value_type>::type
+        pointer;
+
+    _LIBCPP_INLINE_VISIBILITY __hash_map_iterator() {}
+
+    _LIBCPP_INLINE_VISIBILITY __hash_map_iterator(_HashIterator __i) : __i_(__i) {}
+
+    _LIBCPP_INLINE_VISIBILITY reference operator*() const {return *operator->();}
+    _LIBCPP_INLINE_VISIBILITY pointer operator->() const {return (pointer)__i_.operator->();}
+
+    _LIBCPP_INLINE_VISIBILITY __hash_map_iterator& operator++() {++__i_; return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_iterator operator++(int)
+    {
+        __hash_map_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __hash_map_iterator& __x, const __hash_map_iterator& __y)
+        {return __x.__i_ == __y.__i_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __hash_map_iterator& __x, const __hash_map_iterator& __y)
+        {return __x.__i_ != __y.__i_;}
+
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS hash_map;
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS hash_multimap;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
+};
+
+template <class _HashIterator>
+class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator
+{
+    _HashIterator __i_;
+
+    typedef const typename _HashIterator::value_type::first_type key_type;
+    typedef typename _HashIterator::value_type::second_type      mapped_type;
+public:
+    typedef std::forward_iterator_tag                            iterator_category;
+    typedef std::pair<key_type, mapped_type>                     value_type;
+    typedef typename _HashIterator::difference_type              difference_type;
+    typedef const value_type&                                    reference;
+    typedef typename std::__rebind_pointer<typename _HashIterator::pointer, const value_type>::type
+        pointer;
+
+    _LIBCPP_INLINE_VISIBILITY __hash_map_const_iterator() {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_const_iterator(_HashIterator __i) : __i_(__i) {}
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_const_iterator(
+            __hash_map_iterator<typename _HashIterator::__non_const_iterator> __i)
+                : __i_(__i.__i_) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {return *operator->();}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {return (pointer)__i_.operator->();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_const_iterator& operator++() {++__i_; return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_const_iterator operator++(int)
+    {
+        __hash_map_const_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __hash_map_const_iterator& __x, const __hash_map_const_iterator& __y)
+        {return __x.__i_ == __y.__i_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __hash_map_const_iterator& __x, const __hash_map_const_iterator& __y)
+        {return __x.__i_ != __y.__i_;}
+
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS hash_map;
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS hash_multimap;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
+};
+
+template <class _Key, class _Tp, class _Hash = hash<_Key>, class _Pred = std::equal_to<_Key>,
+          class _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
+class _LIBCPP_TEMPLATE_VIS hash_map
+{
+public:
+    // types
+    typedef _Key                                           key_type;
+    typedef _Tp                                            mapped_type;
+    typedef _Tp                                            data_type;
+    typedef _Hash                                          hasher;
+    typedef _Pred                                          key_equal;
+    typedef _Alloc                                         allocator_type;
+    typedef std::pair<const key_type, mapped_type>         value_type;
+    typedef value_type&                                    reference;
+    typedef const value_type&                              const_reference;
+
+private:
+    typedef std::pair<key_type, mapped_type>                    __value_type;
+    typedef __hash_map_hasher<__value_type, hasher>   __hasher;
+    typedef __hash_map_equal<__value_type, key_equal> __key_equal;
+    typedef typename std::__rebind_alloc_helper<
+        std::allocator_traits<allocator_type>, __value_type>::type __allocator_type;
+
+    typedef std::__hash_table<__value_type, __hasher,
+                         __key_equal,  __allocator_type>   __table;
+
+    __table __table_;
+
+    typedef typename __table::__node_pointer               __node_pointer;
+    typedef typename __table::__node_const_pointer         __node_const_pointer;
+    typedef typename __table::__node_traits                __node_traits;
+    typedef typename __table::__node_allocator             __node_allocator;
+    typedef typename __table::__node                       __node;
+    typedef __hash_map_node_destructor<__node_allocator>   _Dp;
+    typedef std::unique_ptr<__node, _Dp>                   __node_holder;
+    typedef std::allocator_traits<allocator_type>          __alloc_traits;
+public:
+    typedef typename __alloc_traits::pointer         pointer;
+    typedef typename __alloc_traits::const_pointer   const_pointer;
+    typedef typename __alloc_traits::size_type       size_type;
+    typedef typename __alloc_traits::difference_type difference_type;
+
+    typedef __hash_map_iterator<typename __table::iterator>       iterator;
+    typedef __hash_map_const_iterator<typename __table::const_iterator> const_iterator;
+
+    _LIBCPP_INLINE_VISIBILITY hash_map() { }
+    explicit hash_map(size_type __n, const hasher& __hf = hasher(),
+                           const key_equal& __eql = key_equal());
+    hash_map(size_type __n, const hasher& __hf,
+                  const key_equal& __eql,
+                  const allocator_type& __a);
+    template <class _InputIterator>
+        hash_map(_InputIterator __first, _InputIterator __last);
+    template <class _InputIterator>
+        hash_map(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf = hasher(),
+                      const key_equal& __eql = key_equal());
+    template <class _InputIterator>
+        hash_map(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf,
+                      const key_equal& __eql,
+                      const allocator_type& __a);
+    hash_map(const hash_map& __u);
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const
+        {return allocator_type(__table_.__node_alloc());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool      empty() const {return __table_.size() == 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const  {return __table_.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const {return __table_.max_size();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       begin()        {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       end()          {return __table_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin()  const {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()    const {return __table_.end();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    std::pair<iterator, bool> insert(const value_type& __x)
+        {return __table_.__insert_unique(__x);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator, const value_type& __x) {return insert(__x).first;}
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        void insert(_InputIterator __first, _InputIterator __last);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void erase(const_iterator __p) {__table_.erase(__p.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type erase(const key_type& __k) {return __table_.__erase_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    void erase(const_iterator __first, const_iterator __last)
+        {__table_.erase(__first.__i_, __last.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() {__table_.clear();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(hash_map& __u) {__table_.swap(__u.__table_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    hasher hash_funct() const
+        {return __table_.hash_function().hash_function();}
+    _LIBCPP_INLINE_VISIBILITY
+    key_equal key_eq() const
+        {return __table_.key_eq().key_eq();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       find(const key_type& __k)       {return __table_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const key_type& __k) const {return __table_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type count(const key_type& __k) const {return __table_.__count_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    std::pair<iterator, iterator>             equal_range(const key_type& __k)
+        {return __table_.__equal_range_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    std::pair<const_iterator, const_iterator> equal_range(const key_type& __k) const
+        {return __table_.__equal_range_unique(__k);}
+
+    mapped_type& operator[](const key_type& __k);
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket_count() const {return __table_.bucket_count();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_bucket_count() const {return __table_.max_bucket_count();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type elems_in_bucket(size_type __n) const
+        {return __table_.bucket_size(__n);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void resize(size_type __n) {__table_.rehash(__n);}
+
+private:
+    __node_holder __construct_node(const key_type& __k);
+};
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>::hash_map(
+        size_type __n, const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+    __table_.rehash(__n);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>::hash_map(
+        size_type __n, const hasher& __hf, const key_equal& __eql,
+        const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+    __table_.rehash(__n);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>::hash_map(
+        _InputIterator __first, _InputIterator __last)
+{
+    insert(__first, __last);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>::hash_map(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>::hash_map(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>::hash_map(
+        const hash_map& __u)
+    : __table_(__u.__table_)
+{
+    __table_.rehash(__u.bucket_count());
+    insert(__u.begin(), __u.end());
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+typename hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>::__node_holder
+hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>::__construct_node(const key_type& __k)
+{
+    __node_allocator& __na = __table_.__node_alloc();
+    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
+    __node_traits::construct(__na, _VSTD::addressof(__h->__value_.first), __k);
+    __h.get_deleter().__first_constructed = true;
+    __node_traits::construct(__na, _VSTD::addressof(__h->__value_.second));
+    __h.get_deleter().__second_constructed = true;
+    return __h;
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+inline
+void
+hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>::insert(_InputIterator __first,
+                                                       _InputIterator __last)
+{
+    for (; __first != __last; ++__first)
+        __table_.__insert_unique(*__first);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+_Tp&
+hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](const key_type& __k)
+{
+    iterator __i = find(__k);
+    if (__i != end())
+        return __i->second;
+    __node_holder __h = __construct_node(__k);
+    std::pair<iterator, bool> __r = __table_.__node_insert_unique(__h.get());
+    __h.release();
+    return __r.first->second;
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+     hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+{
+    __x.swap(__y);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+bool
+operator==(const hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+           const hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+{
+    if (__x.size() != __y.size())
+        return false;
+    typedef typename hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>::const_iterator
+                                                                 const_iterator;
+    for (const_iterator __i = __x.begin(), __ex = __x.end(), __ey = __y.end();
+            __i != __ex; ++__i)
+    {
+        const_iterator __j = __y.find(__i->first);
+        if (__j == __ey || !(*__i == *__j))
+            return false;
+    }
+    return true;
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+           const hash_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Key, class _Tp, class _Hash = hash<_Key>, class _Pred = std::equal_to<_Key>,
+          class _Alloc = std::allocator<std::pair<const _Key, _Tp> > >
+class _LIBCPP_TEMPLATE_VIS hash_multimap
+{
+public:
+    // types
+    typedef _Key                                           key_type;
+    typedef _Tp                                            mapped_type;
+    typedef _Tp                                            data_type;
+    typedef _Hash                                          hasher;
+    typedef _Pred                                          key_equal;
+    typedef _Alloc                                         allocator_type;
+    typedef std::pair<const key_type, mapped_type>         value_type;
+    typedef value_type&                                    reference;
+    typedef const value_type&                              const_reference;
+
+private:
+    typedef std::pair<key_type, mapped_type>               __value_type;
+    typedef __hash_map_hasher<__value_type, hasher>   __hasher;
+    typedef __hash_map_equal<__value_type, key_equal> __key_equal;
+    typedef typename std::__rebind_alloc_helper<std::allocator_traits<allocator_type>, __value_type>::type __allocator_type;
+
+    typedef std::__hash_table<__value_type, __hasher,
+                         __key_equal,  __allocator_type>   __table;
+
+    __table __table_;
+
+    typedef typename __table::__node_traits                __node_traits;
+    typedef typename __table::__node_allocator             __node_allocator;
+    typedef typename __table::__node                       __node;
+    typedef __hash_map_node_destructor<__node_allocator>   _Dp;
+    typedef std::unique_ptr<__node, _Dp>                         __node_holder;
+    typedef std::allocator_traits<allocator_type>               __alloc_traits;
+public:
+    typedef typename __alloc_traits::pointer         pointer;
+    typedef typename __alloc_traits::const_pointer   const_pointer;
+    typedef typename __alloc_traits::size_type       size_type;
+    typedef typename __alloc_traits::difference_type difference_type;
+
+    typedef __hash_map_iterator<typename __table::iterator>       iterator;
+    typedef __hash_map_const_iterator<typename __table::const_iterator> const_iterator;
+
+    _LIBCPP_INLINE_VISIBILITY
+    hash_multimap() { }
+    explicit hash_multimap(size_type __n, const hasher& __hf = hasher(),
+                                const key_equal& __eql = key_equal());
+    hash_multimap(size_type __n, const hasher& __hf,
+                                const key_equal& __eql,
+                                const allocator_type& __a);
+    template <class _InputIterator>
+        hash_multimap(_InputIterator __first, _InputIterator __last);
+    template <class _InputIterator>
+        hash_multimap(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf = hasher(),
+                      const key_equal& __eql = key_equal());
+    template <class _InputIterator>
+        hash_multimap(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf,
+                      const key_equal& __eql,
+                      const allocator_type& __a);
+    hash_multimap(const hash_multimap& __u);
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const
+        {return allocator_type(__table_.__node_alloc());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool      empty() const {return __table_.size() == 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const  {return __table_.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const {return __table_.max_size();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       begin()        {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       end()          {return __table_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin()  const {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()    const {return __table_.end();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const value_type& __x) {return __table_.__insert_multi(__x);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator, const value_type& __x) {return insert(__x);}
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        void insert(_InputIterator __first, _InputIterator __last);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void erase(const_iterator __p) {__table_.erase(__p.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type erase(const key_type& __k) {return __table_.__erase_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    void erase(const_iterator __first, const_iterator __last)
+        {__table_.erase(__first.__i_, __last.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() {__table_.clear();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(hash_multimap& __u) {__table_.swap(__u.__table_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    hasher hash_funct() const
+        {return __table_.hash_function().hash_function();}
+    _LIBCPP_INLINE_VISIBILITY
+    key_equal key_eq() const
+        {return __table_.key_eq().key_eq();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       find(const key_type& __k)       {return __table_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const key_type& __k) const {return __table_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type count(const key_type& __k) const {return __table_.__count_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    std::pair<iterator, iterator>             equal_range(const key_type& __k)
+        {return __table_.__equal_range_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    std::pair<const_iterator, const_iterator> equal_range(const key_type& __k) const
+        {return __table_.__equal_range_multi(__k);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket_count() const {return __table_.bucket_count();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_bucket_count() const {return __table_.max_bucket_count();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type elems_in_bucket(size_type __n) const
+        {return __table_.bucket_size(__n);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void resize(size_type __n) {__table_.rehash(__n);}
+};
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::hash_multimap(
+        size_type __n, const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+    __table_.rehash(__n);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::hash_multimap(
+        size_type __n, const hasher& __hf, const key_equal& __eql,
+        const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+    __table_.rehash(__n);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::hash_multimap(
+        _InputIterator __first, _InputIterator __last)
+{
+    insert(__first, __last);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::hash_multimap(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::hash_multimap(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::hash_multimap(
+        const hash_multimap& __u)
+    : __table_(__u.__table_)
+{
+    __table_.rehash(__u.bucket_count());
+    insert(__u.begin(), __u.end());
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+inline
+void
+hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::insert(_InputIterator __first,
+                                                            _InputIterator __last)
+{
+    for (; __first != __last; ++__first)
+        __table_.__insert_multi(*__first);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+     hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+{
+    __x.swap(__y);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+bool
+operator==(const hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+           const hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+{
+    if (__x.size() != __y.size())
+        return false;
+    typedef typename hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::const_iterator
+                                                                 const_iterator;
+    typedef std::pair<const_iterator, const_iterator> _EqRng;
+    for (const_iterator __i = __x.begin(), __ex = __x.end(); __i != __ex;)
+    {
+        _EqRng __xeq = __x.equal_range(__i->first);
+        _EqRng __yeq = __y.equal_range(__i->first);
+        if (_VSTD::distance(__xeq.first, __xeq.second) !=
+            _VSTD::distance(__yeq.first, __yeq.second) ||
+                  !_VSTD::is_permutation(__xeq.first, __xeq.second, __yeq.first))
+            return false;
+        __i = __xeq.second;
+    }
+    return true;
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+           const hash_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+{
+    return !(__x == __y);
+}
+
+} // __gnu_cxx
+
+#endif // _LIBCPP_HASH_MAP
diff --git a/contrib/libs/cxxsupp/libcxx/include/ext/hash_set b/contrib/libs/cxxsupp/libcxx/include/ext/hash_set
new file mode 100644
index 00000000000..af3f9c5de0c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/ext/hash_set
@@ -0,0 +1,659 @@
+// -*- C++ -*-
+//===------------------------- hash_set ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_HASH_SET
+#define _LIBCPP_HASH_SET
+
+/*
+
+    hash_set synopsis
+
+namespace __gnu_cxx
+{
+
+template <class Value, class Hash = hash<Value>, class Pred = equal_to<Value>,
+          class Alloc = allocator<Value>>
+class hash_set
+{
+public:
+    // types
+    typedef Value                                                      key_type;
+    typedef key_type                                                   value_type;
+    typedef Hash                                                       hasher;
+    typedef Pred                                                       key_equal;
+    typedef Alloc                                                      allocator_type;
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    typedef typename allocator_traits<allocator_type>::pointer         pointer;
+    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
+    typedef typename allocator_traits<allocator_type>::size_type       size_type;
+    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
+
+    typedef /unspecified/ iterator;
+    typedef /unspecified/ const_iterator;
+
+    explicit hash_set(size_type n = 193, const hasher& hf = hasher(),
+                           const key_equal& eql = key_equal(),
+                           const allocator_type& a = allocator_type());
+    template <class InputIterator>
+        hash_set(InputIterator f, InputIterator l,
+                      size_type n = 193, const hasher& hf = hasher(),
+                      const key_equal& eql = key_equal(),
+                      const allocator_type& a = allocator_type());
+    hash_set(const hash_set&);
+    ~hash_set();
+    hash_set& operator=(const hash_set&);
+
+    allocator_type get_allocator() const;
+
+    bool      empty() const;
+    size_type size() const;
+    size_type max_size() const;
+
+    iterator       begin();
+    iterator       end();
+    const_iterator begin()  const;
+    const_iterator end()    const;
+
+    pair<iterator, bool> insert(const value_type& obj);
+    template <class InputIterator>
+        void insert(InputIterator first, InputIterator last);
+
+    void erase(const_iterator position);
+    size_type erase(const key_type& k);
+    void erase(const_iterator first, const_iterator last);
+    void clear();
+
+    void swap(hash_set&);
+
+    hasher hash_funct() const;
+    key_equal key_eq() const;
+
+    iterator       find(const key_type& k);
+    const_iterator find(const key_type& k) const;
+    size_type count(const key_type& k) const;
+    pair<iterator, iterator>             equal_range(const key_type& k);
+    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
+
+    size_type bucket_count() const;
+    size_type max_bucket_count() const;
+
+    size_type elems_in_bucket(size_type n) const;
+
+    void resize(size_type n);
+};
+
+template <class Value, class Hash, class Pred, class Alloc>
+    void swap(hash_set<Value, Hash, Pred, Alloc>& x,
+              hash_set<Value, Hash, Pred, Alloc>& y);
+
+template <class Value, class Hash, class Pred, class Alloc>
+    bool
+    operator==(const hash_set<Value, Hash, Pred, Alloc>& x,
+               const hash_set<Value, Hash, Pred, Alloc>& y);
+
+template <class Value, class Hash, class Pred, class Alloc>
+    bool
+    operator!=(const hash_set<Value, Hash, Pred, Alloc>& x,
+               const hash_set<Value, Hash, Pred, Alloc>& y);
+
+template <class Value, class Hash = hash<Value>, class Pred = equal_to<Value>,
+          class Alloc = allocator<Value>>
+class hash_multiset
+{
+public:
+    // types
+    typedef Value                                                      key_type;
+    typedef key_type                                                   value_type;
+    typedef Hash                                                       hasher;
+    typedef Pred                                                       key_equal;
+    typedef Alloc                                                      allocator_type;
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    typedef typename allocator_traits<allocator_type>::pointer         pointer;
+    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
+    typedef typename allocator_traits<allocator_type>::size_type       size_type;
+    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
+
+    typedef /unspecified/ iterator;
+    typedef /unspecified/ const_iterator;
+
+    explicit hash_multiset(size_type n = 193, const hasher& hf = hasher(),
+                           const key_equal& eql = key_equal(),
+                           const allocator_type& a = allocator_type());
+    template <class InputIterator>
+        hash_multiset(InputIterator f, InputIterator l,
+                      size_type n = 193, const hasher& hf = hasher(),
+                      const key_equal& eql = key_equal(),
+                      const allocator_type& a = allocator_type());
+    hash_multiset(const hash_multiset&);
+    ~hash_multiset();
+    hash_multiset& operator=(const hash_multiset&);
+
+    allocator_type get_allocator() const;
+
+    bool      empty() const;
+    size_type size() const;
+    size_type max_size() const;
+
+    iterator       begin();
+    iterator       end();
+    const_iterator begin()  const;
+    const_iterator end()    const;
+
+    iterator insert(const value_type& obj);
+    template <class InputIterator>
+        void insert(InputIterator first, InputIterator last);
+
+    void erase(const_iterator position);
+    size_type erase(const key_type& k);
+    void erase(const_iterator first, const_iterator last);
+    void clear();
+
+    void swap(hash_multiset&);
+
+    hasher hash_funct() const;
+    key_equal key_eq() const;
+
+    iterator       find(const key_type& k);
+    const_iterator find(const key_type& k) const;
+    size_type count(const key_type& k) const;
+    pair<iterator, iterator>             equal_range(const key_type& k);
+    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
+
+    size_type bucket_count() const;
+    size_type max_bucket_count() const;
+
+    size_type elems_in_bucket(size_type n) const;
+
+    void resize(size_type n);
+};
+
+template <class Value, class Hash, class Pred, class Alloc>
+    void swap(hash_multiset<Value, Hash, Pred, Alloc>& x,
+              hash_multiset<Value, Hash, Pred, Alloc>& y);
+
+template <class Value, class Hash, class Pred, class Alloc>
+    bool
+    operator==(const hash_multiset<Value, Hash, Pred, Alloc>& x,
+               const hash_multiset<Value, Hash, Pred, Alloc>& y);
+
+template <class Value, class Hash, class Pred, class Alloc>
+    bool
+    operator!=(const hash_multiset<Value, Hash, Pred, Alloc>& x,
+               const hash_multiset<Value, Hash, Pred, Alloc>& y);
+}  // __gnu_cxx
+
+*/
+
+#include <__config>
+#include <__hash_table>
+#include <functional>
+#include <ext/__hash>
+
+#if defined(__DEPRECATED) && __DEPRECATED
+#if defined(_LIBCPP_WARNING)
+    _LIBCPP_WARNING("Use of the header <ext/hash_set> is deprecated.  Migrate to <unordered_set>")
+#else
+#   warning Use of the header <ext/hash_set> is deprecated.  Migrate to <unordered_set>
+#endif
+#endif
+
+namespace __gnu_cxx {
+
+
+template <class _Value, class _Hash = hash<_Value>, class _Pred = std::equal_to<_Value>,
+          class _Alloc = std::allocator<_Value> >
+class _LIBCPP_TEMPLATE_VIS hash_set
+{
+public:
+    // types
+    typedef _Value                                                     key_type;
+    typedef key_type                                                   value_type;
+    typedef _Hash                                                      hasher;
+    typedef _Pred                                                      key_equal;
+    typedef _Alloc                                                     allocator_type;
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+
+private:
+    typedef std::__hash_table<value_type, hasher, key_equal, allocator_type> __table;
+
+    __table __table_;
+
+public:
+    typedef typename __table::pointer         pointer;
+    typedef typename __table::const_pointer   const_pointer;
+    typedef typename __table::size_type       size_type;
+    typedef typename __table::difference_type difference_type;
+
+    typedef typename __table::const_iterator       iterator;
+    typedef typename __table::const_iterator       const_iterator;
+
+    _LIBCPP_INLINE_VISIBILITY
+    hash_set() { }
+    explicit hash_set(size_type __n, const hasher& __hf = hasher(),
+                           const key_equal& __eql = key_equal());
+    hash_set(size_type __n, const hasher& __hf, const key_equal& __eql,
+                  const allocator_type& __a);
+    template <class _InputIterator>
+        hash_set(_InputIterator __first, _InputIterator __last);
+    template <class _InputIterator>
+        hash_set(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf = hasher(),
+                      const key_equal& __eql = key_equal());
+    template <class _InputIterator>
+        hash_set(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf, const key_equal& __eql,
+                      const allocator_type& __a);
+    hash_set(const hash_set& __u);
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const
+        {return allocator_type(__table_.__node_alloc());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool      empty() const {return __table_.size() == 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const  {return __table_.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const {return __table_.max_size();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       begin()        {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       end()          {return __table_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin()  const {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()    const {return __table_.end();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    std::pair<iterator, bool> insert(const value_type& __x)
+        {return __table_.__insert_unique(__x);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator, const value_type& __x) {return insert(__x).first;}
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        void insert(_InputIterator __first, _InputIterator __last);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void erase(const_iterator __p) {__table_.erase(__p);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type erase(const key_type& __k) {return __table_.__erase_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    void erase(const_iterator __first, const_iterator __last)
+        {__table_.erase(__first, __last);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() {__table_.clear();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(hash_set& __u) {__table_.swap(__u.__table_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    hasher hash_funct() const {return __table_.hash_function();}
+    _LIBCPP_INLINE_VISIBILITY
+    key_equal key_eq() const {return __table_.key_eq();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       find(const key_type& __k)       {return __table_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const key_type& __k) const {return __table_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type count(const key_type& __k) const {return __table_.__count_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    std::pair<iterator, iterator>             equal_range(const key_type& __k)
+        {return __table_.__equal_range_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    std::pair<const_iterator, const_iterator> equal_range(const key_type& __k) const
+        {return __table_.__equal_range_unique(__k);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket_count() const {return __table_.bucket_count();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_bucket_count() const {return __table_.max_bucket_count();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type elems_in_bucket(size_type __n) const {return __table_.bucket_size(__n);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void resize(size_type __n) {__table_.rehash(__n);}
+};
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+hash_set<_Value, _Hash, _Pred, _Alloc>::hash_set(size_type __n,
+        const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+    __table_.rehash(__n);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+hash_set<_Value, _Hash, _Pred, _Alloc>::hash_set(size_type __n,
+        const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+    __table_.rehash(__n);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+hash_set<_Value, _Hash, _Pred, _Alloc>::hash_set(
+        _InputIterator __first, _InputIterator __last)
+{
+    insert(__first, __last);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+hash_set<_Value, _Hash, _Pred, _Alloc>::hash_set(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+hash_set<_Value, _Hash, _Pred, _Alloc>::hash_set(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+hash_set<_Value, _Hash, _Pred, _Alloc>::hash_set(
+        const hash_set& __u)
+    : __table_(__u.__table_)
+{
+    __table_.rehash(__u.bucket_count());
+    insert(__u.begin(), __u.end());
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+inline
+void
+hash_set<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator __first,
+                                                    _InputIterator __last)
+{
+    for (; __first != __last; ++__first)
+        __table_.__insert_unique(*__first);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(hash_set<_Value, _Hash, _Pred, _Alloc>& __x,
+     hash_set<_Value, _Hash, _Pred, _Alloc>& __y)
+{
+    __x.swap(__y);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+bool
+operator==(const hash_set<_Value, _Hash, _Pred, _Alloc>& __x,
+           const hash_set<_Value, _Hash, _Pred, _Alloc>& __y)
+{
+    if (__x.size() != __y.size())
+        return false;
+    typedef typename hash_set<_Value, _Hash, _Pred, _Alloc>::const_iterator
+                                                                 const_iterator;
+    for (const_iterator __i = __x.begin(), __ex = __x.end(), __ey = __y.end();
+            __i != __ex; ++__i)
+    {
+        const_iterator __j = __y.find(*__i);
+        if (__j == __ey || !(*__i == *__j))
+            return false;
+    }
+    return true;
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const hash_set<_Value, _Hash, _Pred, _Alloc>& __x,
+           const hash_set<_Value, _Hash, _Pred, _Alloc>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Value, class _Hash = hash<_Value>, class _Pred = std::equal_to<_Value>,
+          class _Alloc = std::allocator<_Value> >
+class _LIBCPP_TEMPLATE_VIS hash_multiset
+{
+public:
+    // types
+    typedef _Value                                                     key_type;
+    typedef key_type                                                   value_type;
+    typedef _Hash                                                      hasher;
+    typedef _Pred                                                      key_equal;
+    typedef _Alloc                                                     allocator_type;
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+
+private:
+    typedef std::__hash_table<value_type, hasher, key_equal, allocator_type> __table;
+
+    __table __table_;
+
+public:
+    typedef typename __table::pointer         pointer;
+    typedef typename __table::const_pointer   const_pointer;
+    typedef typename __table::size_type       size_type;
+    typedef typename __table::difference_type difference_type;
+
+    typedef typename __table::const_iterator       iterator;
+    typedef typename __table::const_iterator       const_iterator;
+
+    _LIBCPP_INLINE_VISIBILITY
+    hash_multiset() { }
+    explicit hash_multiset(size_type __n, const hasher& __hf = hasher(),
+                                const key_equal& __eql = key_equal());
+    hash_multiset(size_type __n, const hasher& __hf,
+                       const key_equal& __eql, const allocator_type& __a);
+    template <class _InputIterator>
+        hash_multiset(_InputIterator __first, _InputIterator __last);
+    template <class _InputIterator>
+        hash_multiset(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf = hasher(),
+                      const key_equal& __eql = key_equal());
+    template <class _InputIterator>
+        hash_multiset(_InputIterator __first, _InputIterator __last,
+                      size_type __n , const hasher& __hf,
+                      const key_equal& __eql, const allocator_type& __a);
+    hash_multiset(const hash_multiset& __u);
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const
+        {return allocator_type(__table_.__node_alloc());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool      empty() const {return __table_.size() == 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const  {return __table_.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const {return __table_.max_size();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       begin()        {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       end()          {return __table_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin()  const {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()    const {return __table_.end();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const value_type& __x) {return __table_.__insert_multi(__x);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator, const value_type& __x) {return insert(__x);}
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        void insert(_InputIterator __first, _InputIterator __last);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void erase(const_iterator __p) {__table_.erase(__p);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type erase(const key_type& __k) {return __table_.__erase_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    void erase(const_iterator __first, const_iterator __last)
+        {__table_.erase(__first, __last);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() {__table_.clear();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(hash_multiset& __u) {__table_.swap(__u.__table_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    hasher hash_funct() const {return __table_.hash_function();}
+    _LIBCPP_INLINE_VISIBILITY
+    key_equal key_eq() const {return __table_.key_eq();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       find(const key_type& __k)       {return __table_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const key_type& __k) const {return __table_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type count(const key_type& __k) const {return __table_.__count_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    std::pair<iterator, iterator>             equal_range(const key_type& __k)
+        {return __table_.__equal_range_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    std::pair<const_iterator, const_iterator> equal_range(const key_type& __k) const
+        {return __table_.__equal_range_multi(__k);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket_count() const {return __table_.bucket_count();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_bucket_count() const {return __table_.max_bucket_count();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type elems_in_bucket(size_type __n) const {return __table_.bucket_size(__n);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void resize(size_type __n) {__table_.rehash(__n);}
+};
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+hash_multiset<_Value, _Hash, _Pred, _Alloc>::hash_multiset(
+        size_type __n, const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+    __table_.rehash(__n);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+hash_multiset<_Value, _Hash, _Pred, _Alloc>::hash_multiset(
+        size_type __n, const hasher& __hf, const key_equal& __eql,
+        const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+    __table_.rehash(__n);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+hash_multiset<_Value, _Hash, _Pred, _Alloc>::hash_multiset(
+        _InputIterator __first, _InputIterator __last)
+{
+    insert(__first, __last);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+hash_multiset<_Value, _Hash, _Pred, _Alloc>::hash_multiset(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+hash_multiset<_Value, _Hash, _Pred, _Alloc>::hash_multiset(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+hash_multiset<_Value, _Hash, _Pred, _Alloc>::hash_multiset(
+        const hash_multiset& __u)
+    : __table_(__u.__table_)
+{
+    __table_.rehash(__u.bucket_count());
+    insert(__u.begin(), __u.end());
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+inline
+void
+hash_multiset<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator __first,
+                                                    _InputIterator __last)
+{
+    for (; __first != __last; ++__first)
+        __table_.__insert_multi(*__first);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(hash_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
+     hash_multiset<_Value, _Hash, _Pred, _Alloc>& __y)
+{
+    __x.swap(__y);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+bool
+operator==(const hash_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
+           const hash_multiset<_Value, _Hash, _Pred, _Alloc>& __y)
+{
+    if (__x.size() != __y.size())
+        return false;
+    typedef typename hash_multiset<_Value, _Hash, _Pred, _Alloc>::const_iterator
+                                                                 const_iterator;
+    typedef std::pair<const_iterator, const_iterator> _EqRng;
+    for (const_iterator __i = __x.begin(), __ex = __x.end(); __i != __ex;)
+    {
+        _EqRng __xeq = __x.equal_range(*__i);
+        _EqRng __yeq = __y.equal_range(*__i);
+        if (_VSTD::distance(__xeq.first, __xeq.second) !=
+            _VSTD::distance(__yeq.first, __yeq.second) ||
+                  !_VSTD::is_permutation(__xeq.first, __xeq.second, __yeq.first))
+            return false;
+        __i = __xeq.second;
+    }
+    return true;
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const hash_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
+           const hash_multiset<_Value, _Hash, _Pred, _Alloc>& __y)
+{
+    return !(__x == __y);
+}
+
+} // __gnu_cxx
+
+#endif // _LIBCPP_HASH_SET
diff --git a/contrib/libs/cxxsupp/libcxx/include/filesystem b/contrib/libs/cxxsupp/libcxx/include/filesystem
new file mode 100644
index 00000000000..f503343f87b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/filesystem
@@ -0,0 +1,3026 @@
+// -*- C++ -*-
+//===--------------------------- filesystem -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP_FILESYSTEM
+#define _LIBCPP_FILESYSTEM
+/*
+    filesystem synopsis
+
+    namespace std { namespace filesystem {
+
+    class path;
+
+    void swap(path& lhs, path& rhs) noexcept;
+    size_t hash_value(const path& p) noexcept;
+
+    bool operator==(const path& lhs, const path& rhs) noexcept;
+    bool operator!=(const path& lhs, const path& rhs) noexcept;
+    bool operator< (const path& lhs, const path& rhs) noexcept;
+    bool operator<=(const path& lhs, const path& rhs) noexcept;
+    bool operator> (const path& lhs, const path& rhs) noexcept;
+    bool operator>=(const path& lhs, const path& rhs) noexcept;
+
+    path operator/ (const path& lhs, const path& rhs);
+
+    // fs.path.io operators are friends of path.
+    template <class charT, class traits>
+    friend basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os, const path& p);
+
+    template <class charT, class traits>
+    friend basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is, path& p);
+
+    template <class Source>
+      path u8path(const Source& source);
+    template <class InputIterator>
+      path u8path(InputIterator first, InputIterator last);
+
+    class filesystem_error;
+    class directory_entry;
+
+    class directory_iterator;
+
+    // enable directory_iterator range-based for statements
+    directory_iterator begin(directory_iterator iter) noexcept;
+    directory_iterator end(const directory_iterator&) noexcept;
+
+    class recursive_directory_iterator;
+
+    // enable recursive_directory_iterator range-based for statements
+    recursive_directory_iterator begin(recursive_directory_iterator iter) noexcept;
+    recursive_directory_iterator end(const recursive_directory_iterator&) noexcept;
+
+    class file_status;
+
+    struct space_info
+    {
+      uintmax_t capacity;
+      uintmax_t free;
+      uintmax_t available;
+    };
+
+    enum class file_type;
+    enum class perms;
+    enum class perm_options;
+    enum class copy_options;
+    enum class directory_options;
+
+    typedef chrono::time_point<trivial-clock>  file_time_type;
+
+    // operational functions
+
+    path absolute(const path& p);
+    path absolute(const path& p, error_code &ec);
+
+    path canonical(const path& p);
+    path canonical(const path& p, error_code& ec);
+
+    void copy(const path& from, const path& to);
+    void copy(const path& from, const path& to, error_code& ec);
+    void copy(const path& from, const path& to, copy_options options);
+    void copy(const path& from, const path& to, copy_options options,
+                   error_code& ec);
+
+    bool copy_file(const path& from, const path& to);
+    bool copy_file(const path& from, const path& to, error_code& ec);
+    bool copy_file(const path& from, const path& to, copy_options option);
+    bool copy_file(const path& from, const path& to, copy_options option,
+                           error_code& ec);
+
+    void copy_symlink(const path& existing_symlink, const path& new_symlink);
+    void copy_symlink(const path& existing_symlink, const path& new_symlink,
+                              error_code& ec) noexcept;
+
+    bool create_directories(const path& p);
+    bool create_directories(const path& p, error_code& ec);
+
+    bool create_directory(const path& p);
+    bool create_directory(const path& p, error_code& ec) noexcept;
+
+    bool create_directory(const path& p, const path& attributes);
+    bool create_directory(const path& p, const path& attributes,
+                                  error_code& ec) noexcept;
+
+    void create_directory_symlink(const path& to, const path& new_symlink);
+    void create_directory_symlink(const path& to, const path& new_symlink,
+                                          error_code& ec) noexcept;
+
+    void create_hard_link(const path& to, const path& new_hard_link);
+    void create_hard_link(const path& to, const path& new_hard_link,
+                                  error_code& ec) noexcept;
+
+    void create_symlink(const path& to, const path& new_symlink);
+    void create_symlink(const path& to, const path& new_symlink,
+                                error_code& ec) noexcept;
+
+    path current_path();
+    path current_path(error_code& ec);
+    void current_path(const path& p);
+    void current_path(const path& p, error_code& ec) noexcept;
+
+    bool exists(file_status s) noexcept;
+    bool exists(const path& p);
+    bool exists(const path& p, error_code& ec) noexcept;
+
+    bool equivalent(const path& p1, const path& p2);
+    bool equivalent(const path& p1, const path& p2, error_code& ec) noexcept;
+
+    uintmax_t    file_size(const path& p);
+    uintmax_t    file_size(const path& p, error_code& ec) noexcept;
+
+    uintmax_t    hard_link_count(const path& p);
+    uintmax_t    hard_link_count(const path& p, error_code& ec) noexcept;
+
+    bool is_block_file(file_status s) noexcept;
+    bool is_block_file(const path& p);
+    bool is_block_file(const path& p, error_code& ec) noexcept;
+
+    bool is_character_file(file_status s) noexcept;
+    bool is_character_file(const path& p);
+    bool is_character_file(const path& p, error_code& ec) noexcept;
+
+    bool is_directory(file_status s) noexcept;
+    bool is_directory(const path& p);
+    bool is_directory(const path& p, error_code& ec) noexcept;
+
+    bool is_empty(const path& p);
+    bool is_empty(const path& p, error_code& ec) noexcept;
+
+    bool is_fifo(file_status s) noexcept;
+    bool is_fifo(const path& p);
+    bool is_fifo(const path& p, error_code& ec) noexcept;
+
+    bool is_other(file_status s) noexcept;
+    bool is_other(const path& p);
+    bool is_other(const path& p, error_code& ec) noexcept;
+
+    bool is_regular_file(file_status s) noexcept;
+    bool is_regular_file(const path& p);
+    bool is_regular_file(const path& p, error_code& ec) noexcept;
+
+    bool is_socket(file_status s) noexcept;
+    bool is_socket(const path& p);
+    bool is_socket(const path& p, error_code& ec) noexcept;
+
+    bool is_symlink(file_status s) noexcept;
+    bool is_symlink(const path& p);
+    bool is_symlink(const path& p, error_code& ec) noexcept;
+
+    file_time_type  last_write_time(const path& p);
+    file_time_type  last_write_time(const path& p, error_code& ec) noexcept;
+    void last_write_time(const path& p, file_time_type new_time);
+    void last_write_time(const path& p, file_time_type new_time,
+                                 error_code& ec) noexcept;
+
+    void permissions(const path& p, perms prms,
+                     perm_options opts=perm_options::replace);
+    void permissions(const path& p, perms prms, error_code& ec) noexcept;
+    void permissions(const path& p, perms prms, perm_options opts,
+                     error_code& ec);
+
+    path proximate(const path& p, error_code& ec);
+    path proximate(const path& p, const path& base = current_path());
+    path proximate(const path& p, const path& base, error_code &ec);
+
+    path read_symlink(const path& p);
+    path read_symlink(const path& p, error_code& ec);
+
+    path relative(const path& p, error_code& ec);
+    path relative(const path& p, const path& base=current_path());
+    path relative(const path& p, const path& base, error_code& ec);
+
+    bool remove(const path& p);
+    bool remove(const path& p, error_code& ec) noexcept;
+
+    uintmax_t    remove_all(const path& p);
+    uintmax_t    remove_all(const path& p, error_code& ec);
+
+    void rename(const path& from, const path& to);
+    void rename(const path& from, const path& to, error_code& ec) noexcept;
+
+    void resize_file(const path& p, uintmax_t size);
+    void resize_file(const path& p, uintmax_t size, error_code& ec) noexcept;
+
+    space_info   space(const path& p);
+    space_info   space(const path& p, error_code& ec) noexcept;
+
+    file_status  status(const path& p);
+    file_status  status(const path& p, error_code& ec) noexcept;
+
+    bool status_known(file_status s) noexcept;
+
+    file_status  symlink_status(const path& p);
+    file_status  symlink_status(const path& p, error_code& ec) noexcept;
+
+    path temp_directory_path();
+    path temp_directory_path(error_code& ec);
+
+    path weakly_canonical(path const& p);
+    path weakly_canonical(path const& p, error_code& ec);
+
+
+} }  // namespaces std::filesystem
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <__debug>
+#include <__utility/forward.h>
+#include <chrono>
+#include <compare>
+#include <cstddef>
+#include <cstdlib>
+#include <iosfwd>
+#include <iterator>
+#include <memory>
+#include <stack>
+#include <string>
+#include <string_view>
+#include <system_error>
+#include <utility>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+# include <locale>
+# include <iomanip> // for quoted
+#endif
+
+#if defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
+# error "The Filesystem library is not supported since libc++ has been configured with LIBCXX_ENABLE_FILESYSTEM disabled"
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4141 )
+#endif
+
+#include <__undef_macros>
+
+#ifndef _LIBCPP_CXX03_LANG
+
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+
+_LIBCPP_AVAILABILITY_FILESYSTEM_PUSH
+
+typedef chrono::time_point<_FilesystemClock> file_time_type;
+
+struct _LIBCPP_TYPE_VIS space_info {
+  uintmax_t capacity;
+  uintmax_t free;
+  uintmax_t available;
+};
+
+// On Windows, the library never identifies files as block, character, fifo
+// or socket.
+enum class _LIBCPP_ENUM_VIS file_type : signed char {
+  none = 0,
+  not_found = -1,
+  regular = 1,
+  directory = 2,
+  symlink = 3,
+  block = 4,
+  character = 5,
+  fifo = 6,
+  socket = 7,
+  unknown = 8
+};
+
+// On Windows, these permission bits map to one single readonly flag per
+// file, and the executable bit is always returned as set. When setting
+// permissions, as long as the write bit is set for either owner, group or
+// others, the readonly flag is cleared.
+enum class _LIBCPP_ENUM_VIS perms : unsigned {
+  none = 0,
+
+  owner_read = 0400,
+  owner_write = 0200,
+  owner_exec = 0100,
+  owner_all = 0700,
+
+  group_read = 040,
+  group_write = 020,
+  group_exec = 010,
+  group_all = 070,
+
+  others_read = 04,
+  others_write = 02,
+  others_exec = 01,
+  others_all = 07,
+
+  all = 0777,
+
+  set_uid = 04000,
+  set_gid = 02000,
+  sticky_bit = 01000,
+  mask = 07777,
+  unknown = 0xFFFF,
+};
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr perms operator&(perms _LHS, perms _RHS) {
+  return static_cast<perms>(static_cast<unsigned>(_LHS) &
+                            static_cast<unsigned>(_RHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr perms operator|(perms _LHS, perms _RHS) {
+  return static_cast<perms>(static_cast<unsigned>(_LHS) |
+                            static_cast<unsigned>(_RHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr perms operator^(perms _LHS, perms _RHS) {
+  return static_cast<perms>(static_cast<unsigned>(_LHS) ^
+                            static_cast<unsigned>(_RHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr perms operator~(perms _LHS) {
+  return static_cast<perms>(~static_cast<unsigned>(_LHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline perms& operator&=(perms& _LHS, perms _RHS) { return _LHS = _LHS & _RHS; }
+
+_LIBCPP_INLINE_VISIBILITY
+inline perms& operator|=(perms& _LHS, perms _RHS) { return _LHS = _LHS | _RHS; }
+
+_LIBCPP_INLINE_VISIBILITY
+inline perms& operator^=(perms& _LHS, perms _RHS) { return _LHS = _LHS ^ _RHS; }
+
+enum class _LIBCPP_ENUM_VIS perm_options : unsigned char {
+  replace = 1,
+  add = 2,
+  remove = 4,
+  nofollow = 8
+};
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr perm_options operator&(perm_options _LHS, perm_options _RHS) {
+  return static_cast<perm_options>(static_cast<unsigned>(_LHS) &
+                                   static_cast<unsigned>(_RHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr perm_options operator|(perm_options _LHS, perm_options _RHS) {
+  return static_cast<perm_options>(static_cast<unsigned>(_LHS) |
+                                   static_cast<unsigned>(_RHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr perm_options operator^(perm_options _LHS, perm_options _RHS) {
+  return static_cast<perm_options>(static_cast<unsigned>(_LHS) ^
+                                   static_cast<unsigned>(_RHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr perm_options operator~(perm_options _LHS) {
+  return static_cast<perm_options>(~static_cast<unsigned>(_LHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline perm_options& operator&=(perm_options& _LHS, perm_options _RHS) {
+  return _LHS = _LHS & _RHS;
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline perm_options& operator|=(perm_options& _LHS, perm_options _RHS) {
+  return _LHS = _LHS | _RHS;
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline perm_options& operator^=(perm_options& _LHS, perm_options _RHS) {
+  return _LHS = _LHS ^ _RHS;
+}
+
+enum class _LIBCPP_ENUM_VIS copy_options : unsigned short {
+  none = 0,
+  skip_existing = 1,
+  overwrite_existing = 2,
+  update_existing = 4,
+  recursive = 8,
+  copy_symlinks = 16,
+  skip_symlinks = 32,
+  directories_only = 64,
+  create_symlinks = 128,
+  create_hard_links = 256,
+  __in_recursive_copy = 512,
+};
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr copy_options operator&(copy_options _LHS, copy_options _RHS) {
+  return static_cast<copy_options>(static_cast<unsigned short>(_LHS) &
+                                   static_cast<unsigned short>(_RHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr copy_options operator|(copy_options _LHS, copy_options _RHS) {
+  return static_cast<copy_options>(static_cast<unsigned short>(_LHS) |
+                                   static_cast<unsigned short>(_RHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr copy_options operator^(copy_options _LHS, copy_options _RHS) {
+  return static_cast<copy_options>(static_cast<unsigned short>(_LHS) ^
+                                   static_cast<unsigned short>(_RHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr copy_options operator~(copy_options _LHS) {
+  return static_cast<copy_options>(~static_cast<unsigned short>(_LHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline copy_options& operator&=(copy_options& _LHS, copy_options _RHS) {
+  return _LHS = _LHS & _RHS;
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline copy_options& operator|=(copy_options& _LHS, copy_options _RHS) {
+  return _LHS = _LHS | _RHS;
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline copy_options& operator^=(copy_options& _LHS, copy_options _RHS) {
+  return _LHS = _LHS ^ _RHS;
+}
+
+enum class _LIBCPP_ENUM_VIS directory_options : unsigned char {
+  none = 0,
+  follow_directory_symlink = 1,
+  skip_permission_denied = 2
+};
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr directory_options operator&(directory_options _LHS,
+                                             directory_options _RHS) {
+  return static_cast<directory_options>(static_cast<unsigned char>(_LHS) &
+                                        static_cast<unsigned char>(_RHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr directory_options operator|(directory_options _LHS,
+                                             directory_options _RHS) {
+  return static_cast<directory_options>(static_cast<unsigned char>(_LHS) |
+                                        static_cast<unsigned char>(_RHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr directory_options operator^(directory_options _LHS,
+                                             directory_options _RHS) {
+  return static_cast<directory_options>(static_cast<unsigned char>(_LHS) ^
+                                        static_cast<unsigned char>(_RHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr directory_options operator~(directory_options _LHS) {
+  return static_cast<directory_options>(~static_cast<unsigned char>(_LHS));
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline directory_options& operator&=(directory_options& _LHS,
+                                     directory_options _RHS) {
+  return _LHS = _LHS & _RHS;
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline directory_options& operator|=(directory_options& _LHS,
+                                     directory_options _RHS) {
+  return _LHS = _LHS | _RHS;
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline directory_options& operator^=(directory_options& _LHS,
+                                     directory_options _RHS) {
+  return _LHS = _LHS ^ _RHS;
+}
+
+class _LIBCPP_TYPE_VIS file_status {
+public:
+  // constructors
+  _LIBCPP_INLINE_VISIBILITY
+  file_status() noexcept : file_status(file_type::none) {}
+  _LIBCPP_INLINE_VISIBILITY
+  explicit file_status(file_type __ft, perms __prms = perms::unknown) noexcept
+      : __ft_(__ft),
+        __prms_(__prms) {}
+
+  file_status(const file_status&) noexcept = default;
+  file_status(file_status&&) noexcept = default;
+
+  _LIBCPP_INLINE_VISIBILITY
+  ~file_status() {}
+
+  file_status& operator=(const file_status&) noexcept = default;
+  file_status& operator=(file_status&&) noexcept = default;
+
+  // observers
+  _LIBCPP_INLINE_VISIBILITY
+  file_type type() const noexcept { return __ft_; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  perms permissions() const noexcept { return __prms_; }
+
+  // modifiers
+  _LIBCPP_INLINE_VISIBILITY
+  void type(file_type __ft) noexcept { __ft_ = __ft; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void permissions(perms __p) noexcept { __prms_ = __p; }
+
+private:
+  file_type __ft_;
+  perms __prms_;
+};
+
+class _LIBCPP_TYPE_VIS directory_entry;
+
+template <class _Tp>
+struct __can_convert_char {
+  static const bool value = false;
+};
+template <class _Tp>
+struct __can_convert_char<const _Tp> : public __can_convert_char<_Tp> {};
+template <>
+struct __can_convert_char<char> {
+  static const bool value = true;
+  using __char_type = char;
+};
+template <>
+struct __can_convert_char<wchar_t> {
+  static const bool value = true;
+  using __char_type = wchar_t;
+};
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+template <>
+struct __can_convert_char<char8_t> {
+  static const bool value = true;
+  using __char_type = char8_t;
+};
+#endif
+template <>
+struct __can_convert_char<char16_t> {
+  static const bool value = true;
+  using __char_type = char16_t;
+};
+template <>
+struct __can_convert_char<char32_t> {
+  static const bool value = true;
+  using __char_type = char32_t;
+};
+
+template <class _ECharT>
+typename enable_if<__can_convert_char<_ECharT>::value, bool>::type
+__is_separator(_ECharT __e) {
+#if defined(_LIBCPP_WIN32API)
+  return __e == _ECharT('/') || __e == _ECharT('\\');
+#else
+  return __e == _ECharT('/');
+#endif
+}
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+typedef u8string __u8_string;
+#else
+typedef string __u8_string;
+#endif
+
+struct _NullSentinel {};
+
+template <class _Tp>
+using _Void = void;
+
+template <class _Tp, class = void>
+struct __is_pathable_string : public false_type {};
+
+template <class _ECharT, class _Traits, class _Alloc>
+struct __is_pathable_string<
+    basic_string<_ECharT, _Traits, _Alloc>,
+    _Void<typename __can_convert_char<_ECharT>::__char_type> >
+    : public __can_convert_char<_ECharT> {
+  using _Str = basic_string<_ECharT, _Traits, _Alloc>;
+  using _Base = __can_convert_char<_ECharT>;
+  static _ECharT const* __range_begin(_Str const& __s) { return __s.data(); }
+  static _ECharT const* __range_end(_Str const& __s) {
+    return __s.data() + __s.length();
+  }
+  static _ECharT __first_or_null(_Str const& __s) {
+    return __s.empty() ? _ECharT{} : __s[0];
+  }
+};
+
+template <class _ECharT, class _Traits>
+struct __is_pathable_string<
+    basic_string_view<_ECharT, _Traits>,
+    _Void<typename __can_convert_char<_ECharT>::__char_type> >
+    : public __can_convert_char<_ECharT> {
+  using _Str = basic_string_view<_ECharT, _Traits>;
+  using _Base = __can_convert_char<_ECharT>;
+  static _ECharT const* __range_begin(_Str const& __s) { return __s.data(); }
+  static _ECharT const* __range_end(_Str const& __s) {
+    return __s.data() + __s.length();
+  }
+  static _ECharT __first_or_null(_Str const& __s) {
+    return __s.empty() ? _ECharT{} : __s[0];
+  }
+};
+
+template <class _Source, class _DS = typename decay<_Source>::type,
+          class _UnqualPtrType =
+              typename remove_const<typename remove_pointer<_DS>::type>::type,
+          bool _IsCharPtr = is_pointer<_DS>::value&&
+              __can_convert_char<_UnqualPtrType>::value>
+struct __is_pathable_char_array : false_type {};
+
+template <class _Source, class _ECharT, class _UPtr>
+struct __is_pathable_char_array<_Source, _ECharT*, _UPtr, true>
+    : __can_convert_char<typename remove_const<_ECharT>::type> {
+  using _Base = __can_convert_char<typename remove_const<_ECharT>::type>;
+
+  static _ECharT const* __range_begin(const _ECharT* __b) { return __b; }
+  static _ECharT const* __range_end(const _ECharT* __b) {
+    using _Iter = const _ECharT*;
+    const _ECharT __sentinel = _ECharT{};
+    _Iter __e = __b;
+    for (; *__e != __sentinel; ++__e)
+      ;
+    return __e;
+  }
+
+  static _ECharT __first_or_null(const _ECharT* __b) { return *__b; }
+};
+
+template <class _Iter, bool _IsIt = __is_cpp17_input_iterator<_Iter>::value,
+          class = void>
+struct __is_pathable_iter : false_type {};
+
+template <class _Iter>
+struct __is_pathable_iter<
+    _Iter, true,
+    _Void<typename __can_convert_char<
+        typename iterator_traits<_Iter>::value_type>::__char_type> >
+    : __can_convert_char<typename iterator_traits<_Iter>::value_type> {
+  using _ECharT = typename iterator_traits<_Iter>::value_type;
+  using _Base = __can_convert_char<_ECharT>;
+
+  static _Iter __range_begin(_Iter __b) { return __b; }
+  static _NullSentinel __range_end(_Iter) { return _NullSentinel{}; }
+
+  static _ECharT __first_or_null(_Iter __b) { return *__b; }
+};
+
+template <class _Tp, bool _IsStringT = __is_pathable_string<_Tp>::value,
+          bool _IsCharIterT = __is_pathable_char_array<_Tp>::value,
+          bool _IsIterT = !_IsCharIterT && __is_pathable_iter<_Tp>::value>
+struct __is_pathable : false_type {
+  static_assert(!_IsStringT && !_IsCharIterT && !_IsIterT, "Must all be false");
+};
+
+template <class _Tp>
+struct __is_pathable<_Tp, true, false, false> : __is_pathable_string<_Tp> {};
+
+template <class _Tp>
+struct __is_pathable<_Tp, false, true, false> : __is_pathable_char_array<_Tp> {
+};
+
+template <class _Tp>
+struct __is_pathable<_Tp, false, false, true> : __is_pathable_iter<_Tp> {};
+
+#if defined(_LIBCPP_WIN32API)
+typedef wstring __path_string;
+typedef wchar_t __path_value;
+#else
+typedef string __path_string;
+typedef char __path_value;
+#endif
+
+#if defined(_LIBCPP_WIN32API)
+_LIBCPP_FUNC_VIS
+size_t __wide_to_char(const wstring&, char*, size_t);
+_LIBCPP_FUNC_VIS
+size_t __char_to_wide(const string&, wchar_t*, size_t);
+#endif
+
+template <class _ECharT>
+struct _PathCVT;
+
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+template <class _ECharT>
+struct _PathCVT {
+  static_assert(__can_convert_char<_ECharT>::value,
+                "Char type not convertible");
+
+  typedef __narrow_to_utf8<sizeof(_ECharT) * __CHAR_BIT__> _Narrower;
+#if defined(_LIBCPP_WIN32API)
+  typedef __widen_from_utf8<sizeof(wchar_t) * __CHAR_BIT__> _Widener;
+#endif
+
+  static void __append_range(__path_string& __dest, _ECharT const* __b,
+                             _ECharT const* __e) {
+#if defined(_LIBCPP_WIN32API)
+    string __utf8;
+    _Narrower()(back_inserter(__utf8), __b, __e);
+    _Widener()(back_inserter(__dest), __utf8.data(), __utf8.data() + __utf8.size());
+#else
+    _Narrower()(back_inserter(__dest), __b, __e);
+#endif
+  }
+
+  template <class _Iter>
+  static void __append_range(__path_string& __dest, _Iter __b, _Iter __e) {
+    static_assert(!is_same<_Iter, _ECharT*>::value, "Call const overload");
+    if (__b == __e)
+      return;
+    basic_string<_ECharT> __tmp(__b, __e);
+#if defined(_LIBCPP_WIN32API)
+    string __utf8;
+    _Narrower()(back_inserter(__utf8), __tmp.data(),
+                __tmp.data() + __tmp.length());
+    _Widener()(back_inserter(__dest), __utf8.data(), __utf8.data() + __utf8.size());
+#else
+    _Narrower()(back_inserter(__dest), __tmp.data(),
+                __tmp.data() + __tmp.length());
+#endif
+  }
+
+  template <class _Iter>
+  static void __append_range(__path_string& __dest, _Iter __b, _NullSentinel) {
+    static_assert(!is_same<_Iter, _ECharT*>::value, "Call const overload");
+    const _ECharT __sentinel = _ECharT{};
+    if (*__b == __sentinel)
+      return;
+    basic_string<_ECharT> __tmp;
+    for (; *__b != __sentinel; ++__b)
+      __tmp.push_back(*__b);
+#if defined(_LIBCPP_WIN32API)
+    string __utf8;
+    _Narrower()(back_inserter(__utf8), __tmp.data(),
+                __tmp.data() + __tmp.length());
+    _Widener()(back_inserter(__dest), __utf8.data(), __utf8.data() + __utf8.size());
+#else
+    _Narrower()(back_inserter(__dest), __tmp.data(),
+                __tmp.data() + __tmp.length());
+#endif
+  }
+
+  template <class _Source>
+  static void __append_source(__path_string& __dest, _Source const& __s) {
+    using _Traits = __is_pathable<_Source>;
+    __append_range(__dest, _Traits::__range_begin(__s),
+                   _Traits::__range_end(__s));
+  }
+};
+#endif // !_LIBCPP_HAS_NO_LOCALIZATION
+
+template <>
+struct _PathCVT<__path_value> {
+
+  template <class _Iter>
+  static typename enable_if<__is_exactly_cpp17_input_iterator<_Iter>::value>::type
+  __append_range(__path_string& __dest, _Iter __b, _Iter __e) {
+    for (; __b != __e; ++__b)
+      __dest.push_back(*__b);
+  }
+
+  template <class _Iter>
+  static typename enable_if<__is_cpp17_forward_iterator<_Iter>::value>::type
+  __append_range(__path_string& __dest, _Iter __b, _Iter __e) {
+    __dest.append(__b, __e);
+  }
+
+  template <class _Iter>
+  static void __append_range(__path_string& __dest, _Iter __b, _NullSentinel) {
+    const char __sentinel = char{};
+    for (; *__b != __sentinel; ++__b)
+      __dest.push_back(*__b);
+  }
+
+  template <class _Source>
+  static void __append_source(__path_string& __dest, _Source const& __s) {
+    using _Traits = __is_pathable<_Source>;
+    __append_range(__dest, _Traits::__range_begin(__s),
+                   _Traits::__range_end(__s));
+  }
+};
+
+#if defined(_LIBCPP_WIN32API)
+template <>
+struct _PathCVT<char> {
+
+  static void
+  __append_string(__path_string& __dest, const basic_string<char> &__str) {
+      size_t __size = __char_to_wide(__str, nullptr, 0);
+      size_t __pos = __dest.size();
+      __dest.resize(__pos + __size);
+      __char_to_wide(__str, const_cast<__path_value*>(__dest.data()) + __pos, __size);
+  }
+
+  template <class _Iter>
+  static typename enable_if<__is_exactly_cpp17_input_iterator<_Iter>::value>::type
+  __append_range(__path_string& __dest, _Iter __b, _Iter __e) {
+    basic_string<char> __tmp(__b, __e);
+    __append_string(__dest, __tmp);
+  }
+
+  template <class _Iter>
+  static typename enable_if<__is_cpp17_forward_iterator<_Iter>::value>::type
+  __append_range(__path_string& __dest, _Iter __b, _Iter __e) {
+    basic_string<char> __tmp(__b, __e);
+    __append_string(__dest, __tmp);
+  }
+
+  template <class _Iter>
+  static void __append_range(__path_string& __dest, _Iter __b, _NullSentinel) {
+    const char __sentinel = char{};
+    basic_string<char> __tmp;
+    for (; *__b != __sentinel; ++__b)
+      __tmp.push_back(*__b);
+    __append_string(__dest, __tmp);
+  }
+
+  template <class _Source>
+  static void __append_source(__path_string& __dest, _Source const& __s) {
+    using _Traits = __is_pathable<_Source>;
+    __append_range(__dest, _Traits::__range_begin(__s),
+                   _Traits::__range_end(__s));
+  }
+};
+
+template <class _ECharT>
+struct _PathExport {
+  typedef __narrow_to_utf8<sizeof(wchar_t) * __CHAR_BIT__> _Narrower;
+  typedef __widen_from_utf8<sizeof(_ECharT) * __CHAR_BIT__> _Widener;
+
+  template <class _Str>
+  static void __append(_Str& __dest, const __path_string& __src) {
+    string __utf8;
+    _Narrower()(back_inserter(__utf8), __src.data(), __src.data() + __src.size());
+    _Widener()(back_inserter(__dest), __utf8.data(), __utf8.data() + __utf8.size());
+  }
+};
+
+template <>
+struct _PathExport<char> {
+  template <class _Str>
+  static void __append(_Str& __dest, const __path_string& __src) {
+    size_t __size = __wide_to_char(__src, nullptr, 0);
+    size_t __pos = __dest.size();
+    __dest.resize(__size);
+    __wide_to_char(__src, const_cast<char*>(__dest.data()) + __pos, __size);
+  }
+};
+
+template <>
+struct _PathExport<wchar_t> {
+  template <class _Str>
+  static void __append(_Str& __dest, const __path_string& __src) {
+    __dest.append(__src.begin(), __src.end());
+  }
+};
+
+template <>
+struct _PathExport<char16_t> {
+  template <class _Str>
+  static void __append(_Str& __dest, const __path_string& __src) {
+    __dest.append(__src.begin(), __src.end());
+  }
+};
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+template <>
+struct _PathExport<char8_t> {
+  typedef __narrow_to_utf8<sizeof(wchar_t) * __CHAR_BIT__> _Narrower;
+
+  template <class _Str>
+  static void __append(_Str& __dest, const __path_string& __src) {
+    _Narrower()(back_inserter(__dest), __src.data(), __src.data() + __src.size());
+  }
+};
+#endif /* !_LIBCPP_HAS_NO_CHAR8_T */
+#endif /* _LIBCPP_WIN32API */
+
+class _LIBCPP_TYPE_VIS path {
+  template <class _SourceOrIter, class _Tp = path&>
+  using _EnableIfPathable =
+      typename enable_if<__is_pathable<_SourceOrIter>::value, _Tp>::type;
+
+  template <class _Tp>
+  using _SourceChar = typename __is_pathable<_Tp>::__char_type;
+
+  template <class _Tp>
+  using _SourceCVT = _PathCVT<_SourceChar<_Tp> >;
+
+public:
+#if defined(_LIBCPP_WIN32API)
+  typedef wchar_t value_type;
+  static constexpr value_type preferred_separator = L'\\';
+#else
+  typedef char value_type;
+  static constexpr value_type preferred_separator = '/';
+#endif
+  typedef basic_string<value_type> string_type;
+  typedef basic_string_view<value_type> __string_view;
+
+  enum _LIBCPP_ENUM_VIS format : unsigned char {
+    auto_format,
+    native_format,
+    generic_format
+  };
+
+  // constructors and destructor
+  _LIBCPP_INLINE_VISIBILITY path() noexcept {}
+  _LIBCPP_INLINE_VISIBILITY path(const path& __p) : __pn_(__p.__pn_) {}
+  _LIBCPP_INLINE_VISIBILITY path(path&& __p) noexcept
+      : __pn_(_VSTD::move(__p.__pn_)) {}
+
+  _LIBCPP_INLINE_VISIBILITY
+  path(string_type&& __s, format = format::auto_format) noexcept
+      : __pn_(_VSTD::move(__s)) {}
+
+  template <class _Source, class = _EnableIfPathable<_Source, void> >
+  path(const _Source& __src, format = format::auto_format) {
+    _SourceCVT<_Source>::__append_source(__pn_, __src);
+  }
+
+  template <class _InputIt>
+  path(_InputIt __first, _InputIt __last, format = format::auto_format) {
+    typedef typename iterator_traits<_InputIt>::value_type _ItVal;
+    _PathCVT<_ItVal>::__append_range(__pn_, __first, __last);
+  }
+
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+  // TODO Implement locale conversions.
+  template <class _Source, class = _EnableIfPathable<_Source, void> >
+  path(const _Source& __src, const locale& __loc, format = format::auto_format);
+  template <class _InputIt>
+  path(_InputIt __first, _InputIt _last, const locale& __loc,
+       format = format::auto_format);
+#endif
+
+  _LIBCPP_INLINE_VISIBILITY
+  ~path() = default;
+
+  // assignments
+  _LIBCPP_INLINE_VISIBILITY
+  path& operator=(const path& __p) {
+    __pn_ = __p.__pn_;
+    return *this;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  path& operator=(path&& __p) noexcept {
+    __pn_ = _VSTD::move(__p.__pn_);
+    return *this;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  path& operator=(string_type&& __s) noexcept {
+    __pn_ = _VSTD::move(__s);
+    return *this;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  path& assign(string_type&& __s) noexcept {
+    __pn_ = _VSTD::move(__s);
+    return *this;
+  }
+
+  template <class _Source>
+  _LIBCPP_INLINE_VISIBILITY _EnableIfPathable<_Source>
+  operator=(const _Source& __src) {
+    return this->assign(__src);
+  }
+
+  template <class _Source>
+  _EnableIfPathable<_Source> assign(const _Source& __src) {
+    __pn_.clear();
+    _SourceCVT<_Source>::__append_source(__pn_, __src);
+    return *this;
+  }
+
+  template <class _InputIt>
+  path& assign(_InputIt __first, _InputIt __last) {
+    typedef typename iterator_traits<_InputIt>::value_type _ItVal;
+    __pn_.clear();
+    _PathCVT<_ItVal>::__append_range(__pn_, __first, __last);
+    return *this;
+  }
+
+public:
+  // appends
+#if defined(_LIBCPP_WIN32API)
+  path& operator/=(const path& __p) {
+    auto __p_root_name = __p.__root_name();
+    auto __p_root_name_size = __p_root_name.size();
+    if (__p.is_absolute() ||
+        (!__p_root_name.empty() && __p_root_name != root_name())) {
+      __pn_ = __p.__pn_;
+      return *this;
+    }
+    if (__p.has_root_directory()) {
+      path __root_name_str = root_name();
+      __pn_ = __root_name_str.native();
+      __pn_ += __string_view(__p.__pn_).substr(__p_root_name_size);
+      return *this;
+    }
+    if (has_filename() || (!has_root_directory() && is_absolute()))
+      __pn_ += preferred_separator;
+    __pn_ += __string_view(__p.__pn_).substr(__p_root_name_size);
+    return *this;
+  }
+  template <class _Source>
+  _LIBCPP_INLINE_VISIBILITY _EnableIfPathable<_Source>
+  operator/=(const _Source& __src) {
+    return operator/=(path(__src));
+  }
+
+  template <class _Source>
+  _EnableIfPathable<_Source> append(const _Source& __src) {
+    return operator/=(path(__src));
+  }
+
+  template <class _InputIt>
+  path& append(_InputIt __first, _InputIt __last) {
+    return operator/=(path(__first, __last));
+  }
+#else
+  path& operator/=(const path& __p) {
+    if (__p.is_absolute()) {
+      __pn_ = __p.__pn_;
+      return *this;
+    }
+    if (has_filename())
+      __pn_ += preferred_separator;
+    __pn_ += __p.native();
+    return *this;
+  }
+
+  // FIXME: Use _LIBCPP_DIAGNOSE_WARNING to produce a diagnostic when __src
+  // is known at compile time to be "/' since the user almost certainly intended
+  // to append a separator instead of overwriting the path with "/"
+  template <class _Source>
+  _LIBCPP_INLINE_VISIBILITY _EnableIfPathable<_Source>
+  operator/=(const _Source& __src) {
+    return this->append(__src);
+  }
+
+  template <class _Source>
+  _EnableIfPathable<_Source> append(const _Source& __src) {
+    using _Traits = __is_pathable<_Source>;
+    using _CVT = _PathCVT<_SourceChar<_Source> >;
+    bool __source_is_absolute = __is_separator(_Traits::__first_or_null(__src));
+    if (__source_is_absolute)
+      __pn_.clear();
+    else if (has_filename())
+      __pn_ += preferred_separator;
+    _CVT::__append_source(__pn_, __src);
+    return *this;
+  }
+
+  template <class _InputIt>
+  path& append(_InputIt __first, _InputIt __last) {
+    typedef typename iterator_traits<_InputIt>::value_type _ItVal;
+    static_assert(__can_convert_char<_ItVal>::value, "Must convertible");
+    using _CVT = _PathCVT<_ItVal>;
+    if (__first != __last && __is_separator(*__first))
+      __pn_.clear();
+    else if (has_filename())
+      __pn_ += preferred_separator;
+    _CVT::__append_range(__pn_, __first, __last);
+    return *this;
+  }
+#endif
+
+  // concatenation
+  _LIBCPP_INLINE_VISIBILITY
+  path& operator+=(const path& __x) {
+    __pn_ += __x.__pn_;
+    return *this;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  path& operator+=(const string_type& __x) {
+    __pn_ += __x;
+    return *this;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  path& operator+=(__string_view __x) {
+    __pn_ += __x;
+    return *this;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  path& operator+=(const value_type* __x) {
+    __pn_ += __x;
+    return *this;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  path& operator+=(value_type __x) {
+    __pn_ += __x;
+    return *this;
+  }
+
+  template <class _ECharT>
+  typename enable_if<__can_convert_char<_ECharT>::value, path&>::type
+  operator+=(_ECharT __x) {
+    _PathCVT<_ECharT>::__append_source(__pn_,
+                                       basic_string_view<_ECharT>(&__x, 1));
+    return *this;
+  }
+
+  template <class _Source>
+  _EnableIfPathable<_Source> operator+=(const _Source& __x) {
+    return this->concat(__x);
+  }
+
+  template <class _Source>
+  _EnableIfPathable<_Source> concat(const _Source& __x) {
+    _SourceCVT<_Source>::__append_source(__pn_, __x);
+    return *this;
+  }
+
+  template <class _InputIt>
+  path& concat(_InputIt __first, _InputIt __last) {
+    typedef typename iterator_traits<_InputIt>::value_type _ItVal;
+    _PathCVT<_ItVal>::__append_range(__pn_, __first, __last);
+    return *this;
+  }
+
+  // modifiers
+  _LIBCPP_INLINE_VISIBILITY
+  void clear() noexcept { __pn_.clear(); }
+
+  path& make_preferred() {
+#if defined(_LIBCPP_WIN32API)
+    _VSTD::replace(__pn_.begin(), __pn_.end(), L'/', L'\\');
+#endif
+    return *this;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  path& remove_filename() {
+    auto __fname = __filename();
+    if (!__fname.empty())
+      __pn_.erase(__fname.data() - __pn_.data());
+    return *this;
+  }
+
+  path& replace_filename(const path& __replacement) {
+    remove_filename();
+    return (*this /= __replacement);
+  }
+
+  path& replace_extension(const path& __replacement = path());
+
+  _LIBCPP_INLINE_VISIBILITY
+  void swap(path& __rhs) noexcept { __pn_.swap(__rhs.__pn_); }
+
+  // private helper to allow reserving memory in the path
+  _LIBCPP_INLINE_VISIBILITY
+  void __reserve(size_t __s) { __pn_.reserve(__s); }
+
+  // native format observers
+  _LIBCPP_INLINE_VISIBILITY
+  const string_type& native() const noexcept { return __pn_; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  const value_type* c_str() const noexcept { return __pn_.c_str(); }
+
+  _LIBCPP_INLINE_VISIBILITY operator string_type() const { return __pn_; }
+
+#if defined(_LIBCPP_WIN32API)
+  _LIBCPP_INLINE_VISIBILITY _VSTD::wstring wstring() const { return __pn_; }
+
+  _VSTD::wstring generic_wstring() const {
+    _VSTD::wstring __s;
+    __s.resize(__pn_.size());
+    _VSTD::replace_copy(__pn_.begin(), __pn_.end(), __s.begin(), '\\', '/');
+    return __s;
+  }
+
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+  template <class _ECharT, class _Traits = char_traits<_ECharT>,
+            class _Allocator = allocator<_ECharT> >
+  basic_string<_ECharT, _Traits, _Allocator>
+  string(const _Allocator& __a = _Allocator()) const {
+    using _Str = basic_string<_ECharT, _Traits, _Allocator>;
+    _Str __s(__a);
+    __s.reserve(__pn_.size());
+    _PathExport<_ECharT>::__append(__s, __pn_);
+    return __s;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY _VSTD::string string() const {
+    return string<char>();
+  }
+  _LIBCPP_INLINE_VISIBILITY __u8_string u8string() const {
+    using _CVT = __narrow_to_utf8<sizeof(wchar_t) * __CHAR_BIT__>;
+    __u8_string __s;
+    __s.reserve(__pn_.size());
+    _CVT()(back_inserter(__s), __pn_.data(), __pn_.data() + __pn_.size());
+    return __s;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY _VSTD::u16string u16string() const {
+    return string<char16_t>();
+  }
+  _LIBCPP_INLINE_VISIBILITY _VSTD::u32string u32string() const {
+    return string<char32_t>();
+  }
+
+  // generic format observers
+  template <class _ECharT, class _Traits = char_traits<_ECharT>,
+            class _Allocator = allocator<_ECharT> >
+  basic_string<_ECharT, _Traits, _Allocator>
+  generic_string(const _Allocator& __a = _Allocator()) const {
+    using _Str = basic_string<_ECharT, _Traits, _Allocator>;
+    _Str __s = string<_ECharT, _Traits, _Allocator>(__a);
+    // Note: This (and generic_u8string below) is slightly suboptimal as
+    // it iterates twice over the string; once to convert it to the right
+    // character type, and once to replace path delimiters.
+    _VSTD::replace(__s.begin(), __s.end(),
+                   static_cast<_ECharT>('\\'), static_cast<_ECharT>('/'));
+    return __s;
+  }
+
+  _VSTD::string generic_string() const { return generic_string<char>(); }
+  _VSTD::u16string generic_u16string() const { return generic_string<char16_t>(); }
+  _VSTD::u32string generic_u32string() const { return generic_string<char32_t>(); }
+  __u8_string generic_u8string() const {
+    __u8_string __s = u8string();
+    _VSTD::replace(__s.begin(), __s.end(), '\\', '/');
+    return __s;
+  }
+#endif /* !_LIBCPP_HAS_NO_LOCALIZATION */
+#else /* _LIBCPP_WIN32API */
+
+  _LIBCPP_INLINE_VISIBILITY _VSTD::string string() const { return __pn_; }
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+  _LIBCPP_INLINE_VISIBILITY _VSTD::u8string u8string() const { return _VSTD::u8string(__pn_.begin(), __pn_.end()); }
+#else
+  _LIBCPP_INLINE_VISIBILITY _VSTD::string u8string() const { return __pn_; }
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+  template <class _ECharT, class _Traits = char_traits<_ECharT>,
+            class _Allocator = allocator<_ECharT> >
+  basic_string<_ECharT, _Traits, _Allocator>
+  string(const _Allocator& __a = _Allocator()) const {
+    using _CVT = __widen_from_utf8<sizeof(_ECharT) * __CHAR_BIT__>;
+    using _Str = basic_string<_ECharT, _Traits, _Allocator>;
+    _Str __s(__a);
+    __s.reserve(__pn_.size());
+    _CVT()(back_inserter(__s), __pn_.data(), __pn_.data() + __pn_.size());
+    return __s;
+  }
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+  _LIBCPP_INLINE_VISIBILITY _VSTD::wstring wstring() const {
+    return string<wchar_t>();
+  }
+#endif
+  _LIBCPP_INLINE_VISIBILITY _VSTD::u16string u16string() const {
+    return string<char16_t>();
+  }
+  _LIBCPP_INLINE_VISIBILITY _VSTD::u32string u32string() const {
+    return string<char32_t>();
+  }
+#endif /* !_LIBCPP_HAS_NO_LOCALIZATION */
+
+  // generic format observers
+  _VSTD::string generic_string() const { return __pn_; }
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+  _VSTD::u8string generic_u8string() const { return _VSTD::u8string(__pn_.begin(), __pn_.end()); }
+#else
+  _VSTD::string generic_u8string() const { return __pn_; }
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+  template <class _ECharT, class _Traits = char_traits<_ECharT>,
+            class _Allocator = allocator<_ECharT> >
+  basic_string<_ECharT, _Traits, _Allocator>
+  generic_string(const _Allocator& __a = _Allocator()) const {
+    return string<_ECharT, _Traits, _Allocator>(__a);
+  }
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+  _VSTD::wstring generic_wstring() const { return string<wchar_t>(); }
+#endif
+  _VSTD::u16string generic_u16string() const { return string<char16_t>(); }
+  _VSTD::u32string generic_u32string() const { return string<char32_t>(); }
+#endif /* !_LIBCPP_HAS_NO_LOCALIZATION */
+#endif /* !_LIBCPP_WIN32API */
+
+private:
+  int __compare(__string_view) const;
+  __string_view __root_name() const;
+  __string_view __root_directory() const;
+  __string_view __root_path_raw() const;
+  __string_view __relative_path() const;
+  __string_view __parent_path() const;
+  __string_view __filename() const;
+  __string_view __stem() const;
+  __string_view __extension() const;
+
+public:
+  // compare
+  _LIBCPP_INLINE_VISIBILITY int compare(const path& __p) const noexcept {
+    return __compare(__p.__pn_);
+  }
+  _LIBCPP_INLINE_VISIBILITY int compare(const string_type& __s) const {
+    return __compare(__s);
+  }
+  _LIBCPP_INLINE_VISIBILITY int compare(__string_view __s) const {
+    return __compare(__s);
+  }
+  _LIBCPP_INLINE_VISIBILITY int compare(const value_type* __s) const {
+    return __compare(__s);
+  }
+
+  // decomposition
+  _LIBCPP_INLINE_VISIBILITY path root_name() const {
+    return string_type(__root_name());
+  }
+  _LIBCPP_INLINE_VISIBILITY path root_directory() const {
+    return string_type(__root_directory());
+  }
+  _LIBCPP_INLINE_VISIBILITY path root_path() const {
+#if defined(_LIBCPP_WIN32API)
+    return string_type(__root_path_raw());
+#else
+    return root_name().append(string_type(__root_directory()));
+#endif
+  }
+  _LIBCPP_INLINE_VISIBILITY path relative_path() const {
+    return string_type(__relative_path());
+  }
+  _LIBCPP_INLINE_VISIBILITY path parent_path() const {
+    return string_type(__parent_path());
+  }
+  _LIBCPP_INLINE_VISIBILITY path filename() const {
+    return string_type(__filename());
+  }
+  _LIBCPP_INLINE_VISIBILITY path stem() const { return string_type(__stem()); }
+  _LIBCPP_INLINE_VISIBILITY path extension() const {
+    return string_type(__extension());
+  }
+
+  // query
+  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY bool
+  empty() const noexcept {
+    return __pn_.empty();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY bool has_root_name() const {
+    return !__root_name().empty();
+  }
+  _LIBCPP_INLINE_VISIBILITY bool has_root_directory() const {
+    return !__root_directory().empty();
+  }
+  _LIBCPP_INLINE_VISIBILITY bool has_root_path() const {
+    return !__root_path_raw().empty();
+  }
+  _LIBCPP_INLINE_VISIBILITY bool has_relative_path() const {
+    return !__relative_path().empty();
+  }
+  _LIBCPP_INLINE_VISIBILITY bool has_parent_path() const {
+    return !__parent_path().empty();
+  }
+  _LIBCPP_INLINE_VISIBILITY bool has_filename() const {
+    return !__filename().empty();
+  }
+  _LIBCPP_INLINE_VISIBILITY bool has_stem() const { return !__stem().empty(); }
+  _LIBCPP_INLINE_VISIBILITY bool has_extension() const {
+    return !__extension().empty();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY bool is_absolute() const {
+#if defined(_LIBCPP_WIN32API)
+    __string_view __root_name_str = __root_name();
+    __string_view __root_dir = __root_directory();
+    if (__root_name_str.size() == 2 && __root_name_str[1] == ':') {
+      // A drive letter with no root directory is relative, e.g. x:example.
+      return !__root_dir.empty();
+    }
+    // If no root name, it's relative, e.g. \example is relative to the current drive
+    if (__root_name_str.empty())
+      return false;
+    if (__root_name_str.size() < 3)
+      return false;
+    // A server root name, like \\server, is always absolute
+    if (__root_name_str[0] != '/' && __root_name_str[0] != '\\')
+      return false;
+    if (__root_name_str[1] != '/' && __root_name_str[1] != '\\')
+      return false;
+    // Seems to be a server root name
+    return true;
+#else
+    return has_root_directory();
+#endif
+  }
+  _LIBCPP_INLINE_VISIBILITY bool is_relative() const { return !is_absolute(); }
+
+  // relative paths
+  path lexically_normal() const;
+  path lexically_relative(const path& __base) const;
+
+  _LIBCPP_INLINE_VISIBILITY path lexically_proximate(const path& __base) const {
+    path __result = this->lexically_relative(__base);
+    if (__result.native().empty())
+      return *this;
+    return __result;
+  }
+
+  // iterators
+  class _LIBCPP_TYPE_VIS iterator;
+  typedef iterator const_iterator;
+
+  iterator begin() const;
+  iterator end() const;
+
+#if !defined(_LIBCPP_HAS_NO_LOCALIZATION)
+  template <class _CharT, class _Traits>
+  _LIBCPP_INLINE_VISIBILITY friend
+      typename enable_if<is_same<_CharT, value_type>::value &&
+                             is_same<_Traits, char_traits<value_type> >::value,
+                         basic_ostream<_CharT, _Traits>&>::type
+      operator<<(basic_ostream<_CharT, _Traits>& __os, const path& __p) {
+    __os << _VSTD::__quoted(__p.native());
+    return __os;
+  }
+
+  template <class _CharT, class _Traits>
+  _LIBCPP_INLINE_VISIBILITY friend
+      typename enable_if<!is_same<_CharT, value_type>::value ||
+                             !is_same<_Traits, char_traits<value_type> >::value,
+                         basic_ostream<_CharT, _Traits>&>::type
+      operator<<(basic_ostream<_CharT, _Traits>& __os, const path& __p) {
+    __os << _VSTD::__quoted(__p.string<_CharT, _Traits>());
+    return __os;
+  }
+
+  template <class _CharT, class _Traits>
+  _LIBCPP_INLINE_VISIBILITY friend basic_istream<_CharT, _Traits>&
+  operator>>(basic_istream<_CharT, _Traits>& __is, path& __p) {
+    basic_string<_CharT, _Traits> __tmp;
+    __is >> __quoted(__tmp);
+    __p = __tmp;
+    return __is;
+  }
+#endif // !_LIBCPP_HAS_NO_LOCALIZATION
+
+  friend _LIBCPP_INLINE_VISIBILITY bool operator==(const path& __lhs, const path& __rhs) noexcept {
+    return __lhs.compare(__rhs) == 0;
+  }
+  friend _LIBCPP_INLINE_VISIBILITY bool operator!=(const path& __lhs, const path& __rhs) noexcept {
+    return __lhs.compare(__rhs) != 0;
+  }
+  friend _LIBCPP_INLINE_VISIBILITY bool operator<(const path& __lhs, const path& __rhs) noexcept {
+    return __lhs.compare(__rhs) < 0;
+  }
+  friend _LIBCPP_INLINE_VISIBILITY bool operator<=(const path& __lhs, const path& __rhs) noexcept {
+    return __lhs.compare(__rhs) <= 0;
+  }
+  friend _LIBCPP_INLINE_VISIBILITY bool operator>(const path& __lhs, const path& __rhs) noexcept {
+    return __lhs.compare(__rhs) > 0;
+  }
+  friend _LIBCPP_INLINE_VISIBILITY bool operator>=(const path& __lhs, const path& __rhs) noexcept {
+    return __lhs.compare(__rhs) >= 0;
+  }
+
+  friend _LIBCPP_INLINE_VISIBILITY path operator/(const path& __lhs,
+                                                  const path& __rhs) {
+    path __result(__lhs);
+    __result /= __rhs;
+    return __result;
+  }
+private:
+  inline _LIBCPP_INLINE_VISIBILITY path&
+  __assign_view(__string_view const& __s) noexcept {
+    __pn_ = string_type(__s);
+    return *this;
+  }
+  string_type __pn_;
+};
+
+inline _LIBCPP_INLINE_VISIBILITY void swap(path& __lhs, path& __rhs) noexcept {
+  __lhs.swap(__rhs);
+}
+
+_LIBCPP_FUNC_VIS
+size_t hash_value(const path& __p) noexcept;
+
+template <class _InputIt>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_WITH_CHAR8_T
+    typename enable_if<__is_pathable<_InputIt>::value, path>::type
+    u8path(_InputIt __f, _InputIt __l) {
+  static_assert(
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+      is_same<typename __is_pathable<_InputIt>::__char_type, char8_t>::value ||
+#endif
+      is_same<typename __is_pathable<_InputIt>::__char_type, char>::value,
+      "u8path(Iter, Iter) requires Iter have a value_type of type 'char'"
+      " or 'char8_t'");
+#if defined(_LIBCPP_WIN32API)
+  string __tmp(__f, __l);
+  using _CVT = __widen_from_utf8<sizeof(wchar_t) * __CHAR_BIT__>;
+  _VSTD::wstring __w;
+  __w.reserve(__tmp.size());
+  _CVT()(back_inserter(__w), __tmp.data(), __tmp.data() + __tmp.size());
+  return path(__w);
+#else
+  return path(__f, __l);
+#endif /* !_LIBCPP_WIN32API */
+}
+
+#if defined(_LIBCPP_WIN32API)
+template <class _InputIt>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_WITH_CHAR8_T
+    typename enable_if<__is_pathable<_InputIt>::value, path>::type
+    u8path(_InputIt __f, _NullSentinel) {
+  static_assert(
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+      is_same<typename __is_pathable<_InputIt>::__char_type, char8_t>::value ||
+#endif
+      is_same<typename __is_pathable<_InputIt>::__char_type, char>::value,
+      "u8path(Iter, Iter) requires Iter have a value_type of type 'char'"
+      " or 'char8_t'");
+  string __tmp;
+  const char __sentinel = char{};
+  for (; *__f != __sentinel; ++__f)
+    __tmp.push_back(*__f);
+  using _CVT = __widen_from_utf8<sizeof(wchar_t) * __CHAR_BIT__>;
+  _VSTD::wstring __w;
+  __w.reserve(__tmp.size());
+  _CVT()(back_inserter(__w), __tmp.data(), __tmp.data() + __tmp.size());
+  return path(__w);
+}
+#endif /* _LIBCPP_WIN32API */
+
+template <class _Source>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_DEPRECATED_WITH_CHAR8_T
+    typename enable_if<__is_pathable<_Source>::value, path>::type
+    u8path(const _Source& __s) {
+  static_assert(
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+      is_same<typename __is_pathable<_Source>::__char_type, char8_t>::value ||
+#endif
+      is_same<typename __is_pathable<_Source>::__char_type, char>::value,
+      "u8path(Source const&) requires Source have a character type of type "
+      "'char' or 'char8_t'");
+#if defined(_LIBCPP_WIN32API)
+  using _Traits = __is_pathable<_Source>;
+  return u8path(_VSTD::__unwrap_iter(_Traits::__range_begin(__s)), _VSTD::__unwrap_iter(_Traits::__range_end(__s)));
+#else
+  return path(__s);
+#endif
+}
+
+class _LIBCPP_TYPE_VIS path::iterator {
+public:
+  enum _ParserState : unsigned char {
+    _Singular,
+    _BeforeBegin,
+    _InRootName,
+    _InRootDir,
+    _InFilenames,
+    _InTrailingSep,
+    _AtEnd
+  };
+
+public:
+  typedef bidirectional_iterator_tag iterator_category;
+
+  typedef path value_type;
+  typedef ptrdiff_t difference_type;
+  typedef const path* pointer;
+  typedef const path& reference;
+
+  typedef void
+      __stashing_iterator_tag; // See reverse_iterator and __is_stashing_iterator
+
+public:
+  _LIBCPP_INLINE_VISIBILITY
+  iterator()
+      : __stashed_elem_(), __path_ptr_(nullptr), __entry_(),
+        __state_(_Singular) {}
+
+  iterator(const iterator&) = default;
+  ~iterator() = default;
+
+  iterator& operator=(const iterator&) = default;
+
+  _LIBCPP_INLINE_VISIBILITY
+  reference operator*() const { return __stashed_elem_; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  pointer operator->() const { return &__stashed_elem_; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  iterator& operator++() {
+    _LIBCPP_ASSERT(__state_ != _Singular,
+                   "attempting to increment a singular iterator");
+    _LIBCPP_ASSERT(__state_ != _AtEnd,
+                   "attempting to increment the end iterator");
+    return __increment();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  iterator operator++(int) {
+    iterator __it(*this);
+    this->operator++();
+    return __it;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  iterator& operator--() {
+    _LIBCPP_ASSERT(__state_ != _Singular,
+                   "attempting to decrement a singular iterator");
+    _LIBCPP_ASSERT(__entry_.data() != __path_ptr_->native().data(),
+                   "attempting to decrement the begin iterator");
+    return __decrement();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  iterator operator--(int) {
+    iterator __it(*this);
+    this->operator--();
+    return __it;
+  }
+
+private:
+  friend class path;
+
+  inline _LIBCPP_INLINE_VISIBILITY friend bool operator==(const iterator&,
+                                                          const iterator&);
+
+  iterator& __increment();
+  iterator& __decrement();
+
+  path __stashed_elem_;
+  const path* __path_ptr_;
+  path::__string_view __entry_;
+  _ParserState __state_;
+};
+
+inline _LIBCPP_INLINE_VISIBILITY bool operator==(const path::iterator& __lhs,
+                                                 const path::iterator& __rhs) {
+  return __lhs.__path_ptr_ == __rhs.__path_ptr_ &&
+         __lhs.__entry_.data() == __rhs.__entry_.data();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool operator!=(const path::iterator& __lhs,
+                                                 const path::iterator& __rhs) {
+  return !(__lhs == __rhs);
+}
+
+// TODO(ldionne): We need to pop the pragma and push it again after
+//                filesystem_error to work around PR41078.
+_LIBCPP_AVAILABILITY_FILESYSTEM_POP
+
+class _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_EXCEPTION_ABI filesystem_error : public system_error {
+public:
+  _LIBCPP_INLINE_VISIBILITY
+  filesystem_error(const string& __what, error_code __ec)
+      : system_error(__ec, __what),
+        __storage_(make_shared<_Storage>(path(), path())) {
+    __create_what(0);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  filesystem_error(const string& __what, const path& __p1, error_code __ec)
+      : system_error(__ec, __what),
+        __storage_(make_shared<_Storage>(__p1, path())) {
+    __create_what(1);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  filesystem_error(const string& __what, const path& __p1, const path& __p2,
+                   error_code __ec)
+      : system_error(__ec, __what),
+        __storage_(make_shared<_Storage>(__p1, __p2)) {
+    __create_what(2);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  const path& path1() const noexcept { return __storage_->__p1_; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  const path& path2() const noexcept { return __storage_->__p2_; }
+
+  filesystem_error(const filesystem_error&) = default;
+  ~filesystem_error() override; // key function
+
+  _LIBCPP_INLINE_VISIBILITY
+  const char* what() const noexcept override {
+    return __storage_->__what_.c_str();
+  }
+
+  void __create_what(int __num_paths);
+
+private:
+  struct _LIBCPP_HIDDEN _Storage {
+    _LIBCPP_INLINE_VISIBILITY
+    _Storage(const path& __p1, const path& __p2) : __p1_(__p1), __p2_(__p2) {}
+
+    path __p1_;
+    path __p2_;
+    string __what_;
+  };
+  shared_ptr<_Storage> __storage_;
+};
+
+_LIBCPP_AVAILABILITY_FILESYSTEM_PUSH
+
+template <class... _Args>
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+#ifndef _LIBCPP_NO_EXCEPTIONS
+void __throw_filesystem_error(_Args&&... __args) {
+  throw filesystem_error(_VSTD::forward<_Args>(__args)...);
+}
+#else
+void __throw_filesystem_error(_Args&&...) {
+  _VSTD::abort();
+}
+#endif
+
+// operational functions
+
+_LIBCPP_FUNC_VIS
+path __absolute(const path&, error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+path __canonical(const path&, error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+void __copy(const path& __from, const path& __to, copy_options __opt,
+            error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+bool __copy_file(const path& __from, const path& __to, copy_options __opt,
+                 error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+void __copy_symlink(const path& __existing_symlink, const path& __new_symlink,
+                    error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+bool __create_directories(const path& p, error_code* ec = nullptr);
+_LIBCPP_FUNC_VIS
+bool __create_directory(const path& p, error_code* ec = nullptr);
+_LIBCPP_FUNC_VIS
+bool __create_directory(const path& p, const path& attributes,
+                        error_code* ec = nullptr);
+_LIBCPP_FUNC_VIS
+void __create_directory_symlink(const path& __to, const path& __new_symlink,
+                                error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+void __create_hard_link(const path& __to, const path& __new_hard_link,
+                        error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+void __create_symlink(const path& __to, const path& __new_symlink,
+                      error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+path __current_path(error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+void __current_path(const path&, error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+bool __equivalent(const path&, const path&, error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+uintmax_t __file_size(const path&, error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+uintmax_t __hard_link_count(const path&, error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+bool __fs_is_empty(const path& p, error_code* ec = nullptr);
+_LIBCPP_FUNC_VIS
+file_time_type __last_write_time(const path& p, error_code* ec = nullptr);
+_LIBCPP_FUNC_VIS
+void __last_write_time(const path& p, file_time_type new_time,
+                       error_code* ec = nullptr);
+_LIBCPP_FUNC_VIS
+void __permissions(const path&, perms, perm_options, error_code* = nullptr);
+_LIBCPP_FUNC_VIS
+path __read_symlink(const path& p, error_code* ec = nullptr);
+_LIBCPP_FUNC_VIS
+bool __remove(const path& p, error_code* ec = nullptr);
+_LIBCPP_FUNC_VIS
+uintmax_t __remove_all(const path& p, error_code* ec = nullptr);
+_LIBCPP_FUNC_VIS
+void __rename(const path& from, const path& to, error_code* ec = nullptr);
+_LIBCPP_FUNC_VIS
+void __resize_file(const path& p, uintmax_t size, error_code* ec = nullptr);
+_LIBCPP_FUNC_VIS
+space_info __space(const path&, error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+file_status __status(const path&, error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+file_status __symlink_status(const path&, error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+path __system_complete(const path&, error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+path __temp_directory_path(error_code* __ec = nullptr);
+_LIBCPP_FUNC_VIS
+path __weakly_canonical(path const& __p, error_code* __ec = nullptr);
+
+inline _LIBCPP_INLINE_VISIBILITY path current_path() {
+  return __current_path();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path current_path(error_code& __ec) {
+  return __current_path(&__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void current_path(const path& __p) {
+  __current_path(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void current_path(const path& __p,
+                                                   error_code& __ec) noexcept {
+  __current_path(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path absolute(const path& __p) {
+  return __absolute(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path absolute(const path& __p,
+                                               error_code& __ec) {
+  return __absolute(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path canonical(const path& __p) {
+  return __canonical(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path canonical(const path& __p,
+                                                error_code& __ec) {
+  return __canonical(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void copy(const path& __from,
+                                           const path& __to) {
+  __copy(__from, __to, copy_options::none);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void copy(const path& __from, const path& __to,
+                                           error_code& __ec) {
+  __copy(__from, __to, copy_options::none, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void copy(const path& __from, const path& __to,
+                                           copy_options __opt) {
+  __copy(__from, __to, __opt);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void copy(const path& __from, const path& __to,
+                                           copy_options __opt,
+                                           error_code& __ec) {
+  __copy(__from, __to, __opt, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool copy_file(const path& __from,
+                                                const path& __to) {
+  return __copy_file(__from, __to, copy_options::none);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool
+copy_file(const path& __from, const path& __to, error_code& __ec) {
+  return __copy_file(__from, __to, copy_options::none, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool
+copy_file(const path& __from, const path& __to, copy_options __opt) {
+  return __copy_file(__from, __to, __opt);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool copy_file(const path& __from,
+                                                const path& __to,
+                                                copy_options __opt,
+                                                error_code& __ec) {
+  return __copy_file(__from, __to, __opt, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void copy_symlink(const path& __existing,
+                                                   const path& __new) {
+  __copy_symlink(__existing, __new);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void
+copy_symlink(const path& __ext, const path& __new, error_code& __ec) noexcept {
+  __copy_symlink(__ext, __new, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool create_directories(const path& __p) {
+  return __create_directories(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool create_directories(const path& __p,
+                                                         error_code& __ec) {
+  return __create_directories(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool create_directory(const path& __p) {
+  return __create_directory(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool
+create_directory(const path& __p, error_code& __ec) noexcept {
+  return __create_directory(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool create_directory(const path& __p,
+                                                       const path& __attrs) {
+  return __create_directory(__p, __attrs);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool
+create_directory(const path& __p, const path& __attrs,
+                 error_code& __ec) noexcept {
+  return __create_directory(__p, __attrs, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void
+create_directory_symlink(const path& __to, const path& __new) {
+  __create_directory_symlink(__to, __new);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void
+create_directory_symlink(const path& __to, const path& __new,
+                         error_code& __ec) noexcept {
+  __create_directory_symlink(__to, __new, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void create_hard_link(const path& __to,
+                                                       const path& __new) {
+  __create_hard_link(__to, __new);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void
+create_hard_link(const path& __to, const path& __new,
+                 error_code& __ec) noexcept {
+  __create_hard_link(__to, __new, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void create_symlink(const path& __to,
+                                                     const path& __new) {
+  __create_symlink(__to, __new);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void
+create_symlink(const path& __to, const path& __new, error_code& __ec) noexcept {
+  return __create_symlink(__to, __new, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool status_known(file_status __s) noexcept {
+  return __s.type() != file_type::none;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool exists(file_status __s) noexcept {
+  return status_known(__s) && __s.type() != file_type::not_found;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool exists(const path& __p) {
+  return exists(__status(__p));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool exists(const path& __p,
+                                             error_code& __ec) noexcept {
+  auto __s = __status(__p, &__ec);
+  if (status_known(__s))
+    __ec.clear();
+  return exists(__s);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool equivalent(const path& __p1,
+                                                 const path& __p2) {
+  return __equivalent(__p1, __p2);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool
+equivalent(const path& __p1, const path& __p2, error_code& __ec) noexcept {
+  return __equivalent(__p1, __p2, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY uintmax_t file_size(const path& __p) {
+  return __file_size(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY uintmax_t
+file_size(const path& __p, error_code& __ec) noexcept {
+  return __file_size(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY uintmax_t hard_link_count(const path& __p) {
+  return __hard_link_count(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY uintmax_t
+hard_link_count(const path& __p, error_code& __ec) noexcept {
+  return __hard_link_count(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_block_file(file_status __s) noexcept {
+  return __s.type() == file_type::block;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_block_file(const path& __p) {
+  return is_block_file(__status(__p));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_block_file(const path& __p,
+                                                    error_code& __ec) noexcept {
+  return is_block_file(__status(__p, &__ec));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool
+is_character_file(file_status __s) noexcept {
+  return __s.type() == file_type::character;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_character_file(const path& __p) {
+  return is_character_file(__status(__p));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool
+is_character_file(const path& __p, error_code& __ec) noexcept {
+  return is_character_file(__status(__p, &__ec));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_directory(file_status __s) noexcept {
+  return __s.type() == file_type::directory;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_directory(const path& __p) {
+  return is_directory(__status(__p));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_directory(const path& __p,
+                                                   error_code& __ec) noexcept {
+  return is_directory(__status(__p, &__ec));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_empty(const path& __p) {
+  return __fs_is_empty(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_empty(const path& __p,
+                                               error_code& __ec) {
+  return __fs_is_empty(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_fifo(file_status __s) noexcept {
+  return __s.type() == file_type::fifo;
+}
+inline _LIBCPP_INLINE_VISIBILITY bool is_fifo(const path& __p) {
+  return is_fifo(__status(__p));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_fifo(const path& __p,
+                                              error_code& __ec) noexcept {
+  return is_fifo(__status(__p, &__ec));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool
+is_regular_file(file_status __s) noexcept {
+  return __s.type() == file_type::regular;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_regular_file(const path& __p) {
+  return is_regular_file(__status(__p));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool
+is_regular_file(const path& __p, error_code& __ec) noexcept {
+  return is_regular_file(__status(__p, &__ec));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_socket(file_status __s) noexcept {
+  return __s.type() == file_type::socket;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_socket(const path& __p) {
+  return is_socket(__status(__p));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_socket(const path& __p,
+                                                error_code& __ec) noexcept {
+  return is_socket(__status(__p, &__ec));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_symlink(file_status __s) noexcept {
+  return __s.type() == file_type::symlink;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_symlink(const path& __p) {
+  return is_symlink(__symlink_status(__p));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_symlink(const path& __p,
+                                                 error_code& __ec) noexcept {
+  return is_symlink(__symlink_status(__p, &__ec));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_other(file_status __s) noexcept {
+  return exists(__s) && !is_regular_file(__s) && !is_directory(__s) &&
+         !is_symlink(__s);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_other(const path& __p) {
+  return is_other(__status(__p));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool is_other(const path& __p,
+                                               error_code& __ec) noexcept {
+  return is_other(__status(__p, &__ec));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY file_time_type
+last_write_time(const path& __p) {
+  return __last_write_time(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY file_time_type
+last_write_time(const path& __p, error_code& __ec) noexcept {
+  return __last_write_time(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void last_write_time(const path& __p,
+                                                      file_time_type __t) {
+  __last_write_time(__p, __t);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void
+last_write_time(const path& __p, file_time_type __t,
+                error_code& __ec) noexcept {
+  __last_write_time(__p, __t, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void
+permissions(const path& __p, perms __prms,
+            perm_options __opts = perm_options::replace) {
+  __permissions(__p, __prms, __opts);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void permissions(const path& __p, perms __prms,
+                                                  error_code& __ec) noexcept {
+  __permissions(__p, __prms, perm_options::replace, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void permissions(const path& __p, perms __prms,
+                                                  perm_options __opts,
+                                                  error_code& __ec) {
+  __permissions(__p, __prms, __opts, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path proximate(const path& __p,
+                                                const path& __base,
+                                                error_code& __ec) {
+  path __tmp = __weakly_canonical(__p, &__ec);
+  if (__ec)
+    return {};
+  path __tmp_base = __weakly_canonical(__base, &__ec);
+  if (__ec)
+    return {};
+  return __tmp.lexically_proximate(__tmp_base);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path proximate(const path& __p,
+                                                error_code& __ec) {
+  return proximate(__p, current_path(), __ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path
+proximate(const path& __p, const path& __base = current_path()) {
+  return __weakly_canonical(__p).lexically_proximate(
+      __weakly_canonical(__base));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path read_symlink(const path& __p) {
+  return __read_symlink(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path read_symlink(const path& __p,
+                                                   error_code& __ec) {
+  return __read_symlink(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path relative(const path& __p,
+                                               const path& __base,
+                                               error_code& __ec) {
+  path __tmp = __weakly_canonical(__p, &__ec);
+  if (__ec)
+    return path();
+  path __tmpbase = __weakly_canonical(__base, &__ec);
+  if (__ec)
+    return path();
+  return __tmp.lexically_relative(__tmpbase);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path relative(const path& __p,
+                                               error_code& __ec) {
+  return relative(__p, current_path(), __ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path
+relative(const path& __p, const path& __base = current_path()) {
+  return __weakly_canonical(__p).lexically_relative(__weakly_canonical(__base));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool remove(const path& __p) {
+  return __remove(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool remove(const path& __p,
+                                             error_code& __ec) noexcept {
+  return __remove(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY uintmax_t remove_all(const path& __p) {
+  return __remove_all(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY uintmax_t remove_all(const path& __p,
+                                                      error_code& __ec) {
+  return __remove_all(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void rename(const path& __from,
+                                             const path& __to) {
+  return __rename(__from, __to);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void
+rename(const path& __from, const path& __to, error_code& __ec) noexcept {
+  return __rename(__from, __to, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void resize_file(const path& __p,
+                                                  uintmax_t __ns) {
+  return __resize_file(__p, __ns);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void
+resize_file(const path& __p, uintmax_t __ns, error_code& __ec) noexcept {
+  return __resize_file(__p, __ns, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY space_info space(const path& __p) {
+  return __space(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY space_info space(const path& __p,
+                                                  error_code& __ec) noexcept {
+  return __space(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY file_status status(const path& __p) {
+  return __status(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY file_status status(const path& __p,
+                                                    error_code& __ec) noexcept {
+  return __status(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY file_status symlink_status(const path& __p) {
+  return __symlink_status(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY file_status
+symlink_status(const path& __p, error_code& __ec) noexcept {
+  return __symlink_status(__p, &__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path temp_directory_path() {
+  return __temp_directory_path();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path temp_directory_path(error_code& __ec) {
+  return __temp_directory_path(&__ec);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path weakly_canonical(path const& __p) {
+  return __weakly_canonical(__p);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY path weakly_canonical(path const& __p,
+                                                       error_code& __ec) {
+  return __weakly_canonical(__p, &__ec);
+}
+
+class directory_iterator;
+class recursive_directory_iterator;
+class _LIBCPP_HIDDEN __dir_stream;
+
+class directory_entry {
+  typedef _VSTD_FS::path _Path;
+
+public:
+  // constructors and destructors
+  directory_entry() noexcept = default;
+  directory_entry(directory_entry const&) = default;
+  directory_entry(directory_entry&&) noexcept = default;
+
+  _LIBCPP_INLINE_VISIBILITY
+  explicit directory_entry(_Path const& __p) : __p_(__p) {
+    error_code __ec;
+    __refresh(&__ec);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  directory_entry(_Path const& __p, error_code& __ec) : __p_(__p) {
+    __refresh(&__ec);
+  }
+
+  ~directory_entry() {}
+
+  directory_entry& operator=(directory_entry const&) = default;
+  directory_entry& operator=(directory_entry&&) noexcept = default;
+
+  _LIBCPP_INLINE_VISIBILITY
+  void assign(_Path const& __p) {
+    __p_ = __p;
+    error_code __ec;
+    __refresh(&__ec);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void assign(_Path const& __p, error_code& __ec) {
+    __p_ = __p;
+    __refresh(&__ec);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void replace_filename(_Path const& __p) {
+    __p_.replace_filename(__p);
+    error_code __ec;
+    __refresh(&__ec);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void replace_filename(_Path const& __p, error_code& __ec) {
+    __p_ = __p_.parent_path() / __p;
+    __refresh(&__ec);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void refresh() { __refresh(); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void refresh(error_code& __ec) noexcept { __refresh(&__ec); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  _Path const& path() const noexcept { return __p_; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  operator const _Path&() const noexcept { return __p_; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool exists() const { return _VSTD_FS::exists(file_status{__get_ft()}); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool exists(error_code& __ec) const noexcept {
+    return _VSTD_FS::exists(file_status{__get_ft(&__ec)});
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_block_file() const { return __get_ft() == file_type::block; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_block_file(error_code& __ec) const noexcept {
+    return __get_ft(&__ec) == file_type::block;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_character_file() const { return __get_ft() == file_type::character; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_character_file(error_code& __ec) const noexcept {
+    return __get_ft(&__ec) == file_type::character;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_directory() const { return __get_ft() == file_type::directory; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_directory(error_code& __ec) const noexcept {
+    return __get_ft(&__ec) == file_type::directory;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_fifo() const { return __get_ft() == file_type::fifo; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_fifo(error_code& __ec) const noexcept {
+    return __get_ft(&__ec) == file_type::fifo;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_other() const { return _VSTD_FS::is_other(file_status{__get_ft()}); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_other(error_code& __ec) const noexcept {
+    return _VSTD_FS::is_other(file_status{__get_ft(&__ec)});
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_regular_file() const { return __get_ft() == file_type::regular; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_regular_file(error_code& __ec) const noexcept {
+    return __get_ft(&__ec) == file_type::regular;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_socket() const { return __get_ft() == file_type::socket; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_socket(error_code& __ec) const noexcept {
+    return __get_ft(&__ec) == file_type::socket;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_symlink() const { return __get_sym_ft() == file_type::symlink; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool is_symlink(error_code& __ec) const noexcept {
+    return __get_sym_ft(&__ec) == file_type::symlink;
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  uintmax_t file_size() const { return __get_size(); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  uintmax_t file_size(error_code& __ec) const noexcept {
+    return __get_size(&__ec);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  uintmax_t hard_link_count() const { return __get_nlink(); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  uintmax_t hard_link_count(error_code& __ec) const noexcept {
+    return __get_nlink(&__ec);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  file_time_type last_write_time() const { return __get_write_time(); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  file_time_type last_write_time(error_code& __ec) const noexcept {
+    return __get_write_time(&__ec);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  file_status status() const { return __get_status(); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  file_status status(error_code& __ec) const noexcept {
+    return __get_status(&__ec);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  file_status symlink_status() const { return __get_symlink_status(); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  file_status symlink_status(error_code& __ec) const noexcept {
+    return __get_symlink_status(&__ec);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool operator<(directory_entry const& __rhs) const noexcept {
+    return __p_ < __rhs.__p_;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool operator==(directory_entry const& __rhs) const noexcept {
+    return __p_ == __rhs.__p_;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool operator!=(directory_entry const& __rhs) const noexcept {
+    return __p_ != __rhs.__p_;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool operator<=(directory_entry const& __rhs) const noexcept {
+    return __p_ <= __rhs.__p_;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool operator>(directory_entry const& __rhs) const noexcept {
+    return __p_ > __rhs.__p_;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool operator>=(directory_entry const& __rhs) const noexcept {
+    return __p_ >= __rhs.__p_;
+  }
+
+private:
+  friend class directory_iterator;
+  friend class recursive_directory_iterator;
+  friend class __dir_stream;
+
+  enum _CacheType : unsigned char {
+    _Empty,
+    _IterSymlink,
+    _IterNonSymlink,
+    _RefreshSymlink,
+    _RefreshSymlinkUnresolved,
+    _RefreshNonSymlink
+  };
+
+  struct __cached_data {
+    uintmax_t __size_;
+    uintmax_t __nlink_;
+    file_time_type __write_time_;
+    perms __sym_perms_;
+    perms __non_sym_perms_;
+    file_type __type_;
+    _CacheType __cache_type_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __cached_data() noexcept { __reset(); }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __reset() {
+      __cache_type_ = _Empty;
+      __type_ = file_type::none;
+      __sym_perms_ = __non_sym_perms_ = perms::unknown;
+      __size_ = __nlink_ = uintmax_t(-1);
+      __write_time_ = file_time_type::min();
+    }
+  };
+
+  _LIBCPP_INLINE_VISIBILITY
+  static __cached_data __create_iter_result(file_type __ft) {
+    __cached_data __data;
+    __data.__type_ = __ft;
+    __data.__cache_type_ = [&]() {
+      switch (__ft) {
+      case file_type::none:
+        return _Empty;
+      case file_type::symlink:
+        return _IterSymlink;
+      default:
+        return _IterNonSymlink;
+      }
+    }();
+    return __data;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void __assign_iter_entry(_Path&& __p, __cached_data __dt) {
+    __p_ = _VSTD::move(__p);
+    __data_ = __dt;
+  }
+
+  _LIBCPP_FUNC_VIS
+  error_code __do_refresh() noexcept;
+
+  _LIBCPP_INLINE_VISIBILITY
+  static bool __is_dne_error(error_code const& __ec) {
+    if (!__ec)
+      return true;
+    switch (static_cast<errc>(__ec.value())) {
+    case errc::no_such_file_or_directory:
+    case errc::not_a_directory:
+      return true;
+    default:
+      return false;
+    }
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void __handle_error(const char* __msg, error_code* __dest_ec,
+                      error_code const& __ec, bool __allow_dne = false) const {
+    if (__dest_ec) {
+      *__dest_ec = __ec;
+      return;
+    }
+    if (__ec && (!__allow_dne || !__is_dne_error(__ec)))
+      __throw_filesystem_error(__msg, __p_, __ec);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void __refresh(error_code* __ec = nullptr) {
+    __handle_error("in directory_entry::refresh", __ec, __do_refresh(),
+                   /*allow_dne*/ true);
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  file_type __get_sym_ft(error_code* __ec = nullptr) const {
+    switch (__data_.__cache_type_) {
+    case _Empty:
+      return __symlink_status(__p_, __ec).type();
+    case _IterSymlink:
+    case _RefreshSymlink:
+    case _RefreshSymlinkUnresolved:
+      if (__ec)
+        __ec->clear();
+      return file_type::symlink;
+    case _IterNonSymlink:
+    case _RefreshNonSymlink:
+      file_status __st(__data_.__type_);
+      if (__ec && !_VSTD_FS::exists(__st))
+        *__ec = make_error_code(errc::no_such_file_or_directory);
+      else if (__ec)
+        __ec->clear();
+      return __data_.__type_;
+    }
+    _LIBCPP_UNREACHABLE();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  file_type __get_ft(error_code* __ec = nullptr) const {
+    switch (__data_.__cache_type_) {
+    case _Empty:
+    case _IterSymlink:
+    case _RefreshSymlinkUnresolved:
+      return __status(__p_, __ec).type();
+    case _IterNonSymlink:
+    case _RefreshNonSymlink:
+    case _RefreshSymlink: {
+      file_status __st(__data_.__type_);
+      if (__ec && !_VSTD_FS::exists(__st))
+        *__ec = make_error_code(errc::no_such_file_or_directory);
+      else if (__ec)
+        __ec->clear();
+      return __data_.__type_;
+    }
+    }
+    _LIBCPP_UNREACHABLE();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  file_status __get_status(error_code* __ec = nullptr) const {
+    switch (__data_.__cache_type_) {
+    case _Empty:
+    case _IterNonSymlink:
+    case _IterSymlink:
+    case _RefreshSymlinkUnresolved:
+      return __status(__p_, __ec);
+    case _RefreshNonSymlink:
+    case _RefreshSymlink:
+      return file_status(__get_ft(__ec), __data_.__non_sym_perms_);
+    }
+    _LIBCPP_UNREACHABLE();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  file_status __get_symlink_status(error_code* __ec = nullptr) const {
+    switch (__data_.__cache_type_) {
+    case _Empty:
+    case _IterNonSymlink:
+    case _IterSymlink:
+      return __symlink_status(__p_, __ec);
+    case _RefreshNonSymlink:
+      return file_status(__get_sym_ft(__ec), __data_.__non_sym_perms_);
+    case _RefreshSymlink:
+    case _RefreshSymlinkUnresolved:
+      return file_status(__get_sym_ft(__ec), __data_.__sym_perms_);
+    }
+    _LIBCPP_UNREACHABLE();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  uintmax_t __get_size(error_code* __ec = nullptr) const {
+    switch (__data_.__cache_type_) {
+    case _Empty:
+    case _IterNonSymlink:
+    case _IterSymlink:
+    case _RefreshSymlinkUnresolved:
+      return _VSTD_FS::__file_size(__p_, __ec);
+    case _RefreshSymlink:
+    case _RefreshNonSymlink: {
+      error_code __m_ec;
+      file_status __st(__get_ft(&__m_ec));
+      __handle_error("in directory_entry::file_size", __ec, __m_ec);
+      if (_VSTD_FS::exists(__st) && !_VSTD_FS::is_regular_file(__st)) {
+        errc __err_kind = _VSTD_FS::is_directory(__st) ? errc::is_a_directory
+                                                       : errc::not_supported;
+        __handle_error("in directory_entry::file_size", __ec,
+                       make_error_code(__err_kind));
+      }
+      return __data_.__size_;
+    }
+    }
+    _LIBCPP_UNREACHABLE();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  uintmax_t __get_nlink(error_code* __ec = nullptr) const {
+    switch (__data_.__cache_type_) {
+    case _Empty:
+    case _IterNonSymlink:
+    case _IterSymlink:
+    case _RefreshSymlinkUnresolved:
+      return _VSTD_FS::__hard_link_count(__p_, __ec);
+    case _RefreshSymlink:
+    case _RefreshNonSymlink: {
+      error_code __m_ec;
+      (void)__get_ft(&__m_ec);
+      __handle_error("in directory_entry::hard_link_count", __ec, __m_ec);
+      return __data_.__nlink_;
+    }
+    }
+    _LIBCPP_UNREACHABLE();
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  file_time_type __get_write_time(error_code* __ec = nullptr) const {
+    switch (__data_.__cache_type_) {
+    case _Empty:
+    case _IterNonSymlink:
+    case _IterSymlink:
+    case _RefreshSymlinkUnresolved:
+      return _VSTD_FS::__last_write_time(__p_, __ec);
+    case _RefreshSymlink:
+    case _RefreshNonSymlink: {
+      error_code __m_ec;
+      file_status __st(__get_ft(&__m_ec));
+      __handle_error("in directory_entry::last_write_time", __ec, __m_ec);
+      if (_VSTD_FS::exists(__st) &&
+          __data_.__write_time_ == file_time_type::min())
+        __handle_error("in directory_entry::last_write_time", __ec,
+                       make_error_code(errc::value_too_large));
+      return __data_.__write_time_;
+    }
+    }
+    _LIBCPP_UNREACHABLE();
+  }
+
+private:
+  _Path __p_;
+  __cached_data __data_;
+};
+
+class __dir_element_proxy {
+public:
+  inline _LIBCPP_INLINE_VISIBILITY directory_entry operator*() {
+    return _VSTD::move(__elem_);
+  }
+
+private:
+  friend class directory_iterator;
+  friend class recursive_directory_iterator;
+  explicit __dir_element_proxy(directory_entry const& __e) : __elem_(__e) {}
+  __dir_element_proxy(__dir_element_proxy&& __o)
+      : __elem_(_VSTD::move(__o.__elem_)) {}
+  directory_entry __elem_;
+};
+
+class directory_iterator {
+public:
+  typedef directory_entry value_type;
+  typedef ptrdiff_t difference_type;
+  typedef value_type const* pointer;
+  typedef value_type const& reference;
+  typedef input_iterator_tag iterator_category;
+
+public:
+  //ctor & dtor
+  directory_iterator() noexcept {}
+
+  explicit directory_iterator(const path& __p)
+      : directory_iterator(__p, nullptr) {}
+
+  directory_iterator(const path& __p, directory_options __opts)
+      : directory_iterator(__p, nullptr, __opts) {}
+
+  directory_iterator(const path& __p, error_code& __ec)
+      : directory_iterator(__p, &__ec) {}
+
+  directory_iterator(const path& __p, directory_options __opts,
+                     error_code& __ec)
+      : directory_iterator(__p, &__ec, __opts) {}
+
+  directory_iterator(const directory_iterator&) = default;
+  directory_iterator(directory_iterator&&) = default;
+  directory_iterator& operator=(const directory_iterator&) = default;
+
+  directory_iterator& operator=(directory_iterator&& __o) noexcept {
+    // non-default implementation provided to support self-move assign.
+    if (this != &__o) {
+      __imp_ = _VSTD::move(__o.__imp_);
+    }
+    return *this;
+  }
+
+  ~directory_iterator() = default;
+
+  const directory_entry& operator*() const {
+    _LIBCPP_ASSERT(__imp_, "The end iterator cannot be dereferenced");
+    return __dereference();
+  }
+
+  const directory_entry* operator->() const { return &**this; }
+
+  directory_iterator& operator++() { return __increment(); }
+
+  __dir_element_proxy operator++(int) {
+    __dir_element_proxy __p(**this);
+    __increment();
+    return __p;
+  }
+
+  directory_iterator& increment(error_code& __ec) { return __increment(&__ec); }
+
+private:
+  inline _LIBCPP_INLINE_VISIBILITY friend bool
+  operator==(const directory_iterator& __lhs,
+             const directory_iterator& __rhs) noexcept;
+
+  // construct the dir_stream
+  _LIBCPP_FUNC_VIS
+  directory_iterator(const path&, error_code*,
+                     directory_options = directory_options::none);
+
+  _LIBCPP_FUNC_VIS
+  directory_iterator& __increment(error_code* __ec = nullptr);
+
+  _LIBCPP_FUNC_VIS
+  const directory_entry& __dereference() const;
+
+private:
+  shared_ptr<__dir_stream> __imp_;
+};
+
+inline _LIBCPP_INLINE_VISIBILITY bool
+operator==(const directory_iterator& __lhs,
+           const directory_iterator& __rhs) noexcept {
+  return __lhs.__imp_ == __rhs.__imp_;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY bool
+operator!=(const directory_iterator& __lhs,
+           const directory_iterator& __rhs) noexcept {
+  return !(__lhs == __rhs);
+}
+
+// enable directory_iterator range-based for statements
+inline _LIBCPP_INLINE_VISIBILITY directory_iterator
+begin(directory_iterator __iter) noexcept {
+  return __iter;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY directory_iterator
+end(const directory_iterator&) noexcept {
+  return directory_iterator();
+}
+
+class recursive_directory_iterator {
+public:
+  using value_type = directory_entry;
+  using difference_type = ptrdiff_t;
+  using pointer = directory_entry const*;
+  using reference = directory_entry const&;
+  using iterator_category = input_iterator_tag;
+
+public:
+  // constructors and destructor
+  _LIBCPP_INLINE_VISIBILITY
+  recursive_directory_iterator() noexcept : __rec_(false) {}
+
+  _LIBCPP_INLINE_VISIBILITY
+  explicit recursive_directory_iterator(
+      const path& __p, directory_options __xoptions = directory_options::none)
+      : recursive_directory_iterator(__p, __xoptions, nullptr) {}
+
+  _LIBCPP_INLINE_VISIBILITY
+  recursive_directory_iterator(const path& __p, directory_options __xoptions,
+                               error_code& __ec)
+      : recursive_directory_iterator(__p, __xoptions, &__ec) {}
+
+  _LIBCPP_INLINE_VISIBILITY
+  recursive_directory_iterator(const path& __p, error_code& __ec)
+      : recursive_directory_iterator(__p, directory_options::none, &__ec) {}
+
+  recursive_directory_iterator(const recursive_directory_iterator&) = default;
+  recursive_directory_iterator(recursive_directory_iterator&&) = default;
+
+  recursive_directory_iterator&
+  operator=(const recursive_directory_iterator&) = default;
+
+  _LIBCPP_INLINE_VISIBILITY
+  recursive_directory_iterator&
+  operator=(recursive_directory_iterator&& __o) noexcept {
+    // non-default implementation provided to support self-move assign.
+    if (this != &__o) {
+      __imp_ = _VSTD::move(__o.__imp_);
+      __rec_ = __o.__rec_;
+    }
+    return *this;
+  }
+
+  ~recursive_directory_iterator() = default;
+
+  _LIBCPP_INLINE_VISIBILITY
+  const directory_entry& operator*() const { return __dereference(); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  const directory_entry* operator->() const { return &__dereference(); }
+
+  recursive_directory_iterator& operator++() { return __increment(); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  __dir_element_proxy operator++(int) {
+    __dir_element_proxy __p(**this);
+    __increment();
+    return __p;
+  }
+
+  _LIBCPP_INLINE_VISIBILITY
+  recursive_directory_iterator& increment(error_code& __ec) {
+    return __increment(&__ec);
+  }
+
+  _LIBCPP_FUNC_VIS directory_options options() const;
+  _LIBCPP_FUNC_VIS int depth() const;
+
+  _LIBCPP_INLINE_VISIBILITY
+  void pop() { __pop(); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void pop(error_code& __ec) { __pop(&__ec); }
+
+  _LIBCPP_INLINE_VISIBILITY
+  bool recursion_pending() const { return __rec_; }
+
+  _LIBCPP_INLINE_VISIBILITY
+  void disable_recursion_pending() { __rec_ = false; }
+
+private:
+  _LIBCPP_FUNC_VIS
+  recursive_directory_iterator(const path& __p, directory_options __opt,
+                               error_code* __ec);
+
+  _LIBCPP_FUNC_VIS
+  const directory_entry& __dereference() const;
+
+  _LIBCPP_FUNC_VIS
+  bool __try_recursion(error_code* __ec);
+
+  _LIBCPP_FUNC_VIS
+  void __advance(error_code* __ec = nullptr);
+
+  _LIBCPP_FUNC_VIS
+  recursive_directory_iterator& __increment(error_code* __ec = nullptr);
+
+  _LIBCPP_FUNC_VIS
+  void __pop(error_code* __ec = nullptr);
+
+  inline _LIBCPP_INLINE_VISIBILITY friend bool
+  operator==(const recursive_directory_iterator&,
+             const recursive_directory_iterator&) noexcept;
+
+  struct _LIBCPP_HIDDEN __shared_imp;
+  shared_ptr<__shared_imp> __imp_;
+  bool __rec_;
+}; // class recursive_directory_iterator
+
+inline _LIBCPP_INLINE_VISIBILITY bool
+operator==(const recursive_directory_iterator& __lhs,
+           const recursive_directory_iterator& __rhs) noexcept {
+  return __lhs.__imp_ == __rhs.__imp_;
+}
+
+_LIBCPP_INLINE_VISIBILITY
+inline bool operator!=(const recursive_directory_iterator& __lhs,
+                       const recursive_directory_iterator& __rhs) noexcept {
+  return !(__lhs == __rhs);
+}
+// enable recursive_directory_iterator range-based for statements
+inline _LIBCPP_INLINE_VISIBILITY recursive_directory_iterator
+begin(recursive_directory_iterator __iter) noexcept {
+  return __iter;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY recursive_directory_iterator
+end(const recursive_directory_iterator&) noexcept {
+  return recursive_directory_iterator();
+}
+
+_LIBCPP_AVAILABILITY_FILESYSTEM_POP
+
+_LIBCPP_END_NAMESPACE_FILESYSTEM
+
+#endif // !_LIBCPP_CXX03_LANG
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_FILESYSTEM
diff --git a/contrib/libs/cxxsupp/libcxx/include/float.h b/contrib/libs/cxxsupp/libcxx/include/float.h
new file mode 100644
index 00000000000..ec7197e2922
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/float.h
@@ -0,0 +1,97 @@
+// -*- C++ -*-
+//===--------------------------- float.h ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_FLOAT_H
+#define _LIBCPP_FLOAT_H
+
+/*
+    float.h synopsis
+
+Macros:
+
+    FLT_ROUNDS
+    FLT_EVAL_METHOD     // C99
+    FLT_RADIX
+
+    FLT_MANT_DIG
+    DBL_MANT_DIG
+    LDBL_MANT_DIG
+
+    FLT_HAS_SUBNORM     // C11
+    DBL_HAS_SUBNORM     // C11
+    LDBL_HAS_SUBNORM    // C11
+
+    DECIMAL_DIG         // C99
+    FLT_DECIMAL_DIG     // C11
+    DBL_DECIMAL_DIG     // C11
+    LDBL_DECIMAL_DIG    // C11
+
+    FLT_DIG
+    DBL_DIG
+    LDBL_DIG
+
+    FLT_MIN_EXP
+    DBL_MIN_EXP
+    LDBL_MIN_EXP
+
+    FLT_MIN_10_EXP
+    DBL_MIN_10_EXP
+    LDBL_MIN_10_EXP
+
+    FLT_MAX_EXP
+    DBL_MAX_EXP
+    LDBL_MAX_EXP
+
+    FLT_MAX_10_EXP
+    DBL_MAX_10_EXP
+    LDBL_MAX_10_EXP
+
+    FLT_MAX
+    DBL_MAX
+    LDBL_MAX
+
+    FLT_EPSILON
+    DBL_EPSILON
+    LDBL_EPSILON
+
+    FLT_MIN
+    DBL_MIN
+    LDBL_MIN
+
+    FLT_TRUE_MIN        // C11
+    DBL_TRUE_MIN        // C11
+    LDBL_TRUE_MIN       // C11
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(float.h)
+#else
+#include_next <float.h>
+#endif
+
+#ifdef __cplusplus
+
+#ifndef FLT_EVAL_METHOD
+#define FLT_EVAL_METHOD __FLT_EVAL_METHOD__
+#endif
+
+#ifndef DECIMAL_DIG
+#define DECIMAL_DIG __DECIMAL_DIG__
+#endif
+
+#endif // __cplusplus
+
+#endif // _LIBCPP_FLOAT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/format b/contrib/libs/cxxsupp/libcxx/include/format
new file mode 100644
index 00000000000..19f642716b1
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/format
@@ -0,0 +1,776 @@
+// -*- C++ -*-
+//===--------------------------- format -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_FORMAT
+#define _LIBCPP_FORMAT
+
+/*
+
+namespace std {
+  // [format.context], class template basic_format_context
+  template<class Out, class charT>
+  class basic_format_context {
+    basic_format_args<basic_format_context> args_;      // exposition only
+    Out out_;                                           // exposition only
+
+  public:
+    using iterator = Out;
+    using char_type = charT;
+    template<class T> using formatter_type = formatter<T, charT>;
+
+    basic_format_arg<basic_format_context> arg(size_t id) const;
+    std::locale locale();
+
+    iterator out();
+    void advance_to(iterator it);
+  };
+  using format_context = basic_format_context<unspecified, char>;
+  using wformat_context = basic_format_context<unspecified, wchar_t>;
+
+  // [format.args], class template basic_format_args
+  template<class Context>
+  class basic_format_args {
+    size_t size_;                               // exposition only
+    const basic_format_arg<Context>* data_;     // exposition only
+
+  public:
+    basic_format_args() noexcept;
+
+    template<class... Args>
+      basic_format_args(const format-arg-store<Context, Args...>& store) noexcept;
+
+    basic_format_arg<Context> get(size_t i) const noexcept;
+  };
+  using format_args = basic_format_args<format_context>;
+  using wformat_args = basic_format_args<wformat_context>;
+
+
+  template<class Out, class charT>
+    using format_args_t = basic_format_args<basic_format_context<Out, charT>>;
+
+  // [format.functions], formatting functions
+  template<class... Args>
+    string format(string_view fmt, const Args&... args);
+  template<class... Args>
+    wstring format(wstring_view fmt, const Args&... args);
+  template<class... Args>
+    string format(const locale& loc, string_view fmt, const Args&... args);
+  template<class... Args>
+    wstring format(const locale& loc, wstring_view fmt, const Args&... args);
+
+  string vformat(string_view fmt, format_args args);
+  wstring vformat(wstring_view fmt, wformat_args args);
+  string vformat(const locale& loc, string_view fmt, format_args args);
+  wstring vformat(const locale& loc, wstring_view fmt, wformat_args args);
+
+  template<class Out, class... Args>
+    Out format_to(Out out, string_view fmt, const Args&... args);
+  template<class Out, class... Args>
+    Out format_to(Out out, wstring_view fmt, const Args&... args);
+  template<class Out, class... Args>
+    Out format_to(Out out, const locale& loc, string_view fmt, const Args&... args);
+  template<class Out, class... Args>
+    Out format_to(Out out, const locale& loc, wstring_view fmt, const Args&... args);
+
+  template<class Out>
+    Out vformat_to(Out out, string_view fmt,
+                   format_args_t<type_identity_t<Out>, char> args);
+  template<class Out>
+    Out vformat_to(Out out, wstring_view fmt,
+                   format_args_t<type_identity_t<Out>, wchar_t> args);
+  template<class Out>
+    Out vformat_to(Out out, const locale& loc, string_view fmt,
+                   format_args_t<type_identity_t<Out>, char> args);
+  template<class Out>
+    Out vformat_to(Out out, const locale& loc, wstring_view fmt,
+                   format_args_t<type_identity_t<Out>, wchar_t> args);
+
+  template<class Out> struct format_to_n_result {
+    Out out;
+    iter_difference_t<Out> size;
+  };
+
+ template<class Out, class... Args>
+    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
+                                        string_view fmt, const Args&... args);
+  template<class Out, class... Args>
+    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
+                                        wstring_view fmt, const Args&... args);
+  template<class Out, class... Args>
+    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
+                                        const locale& loc, string_view fmt,
+                                        const Args&... args);
+  template<class Out, class... Args>
+    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
+                                        const locale& loc, wstring_view fmt,
+                                        const Args&... args);
+
+  template<class... Args>
+    size_t formatted_size(string_view fmt, const Args&... args);
+  template<class... Args>
+    size_t formatted_size(wstring_view fmt, const Args&... args);
+  template<class... Args>
+    size_t formatted_size(const locale& loc, string_view fmt, const Args&... args);
+  template<class... Args>
+    size_t formatted_size(const locale& loc, wstring_view fmt, const Args&... args);
+
+  // [format.formatter], formatter
+  template<> struct formatter<char, char>;
+  template<> struct formatter<char, wchar_t>;
+  template<> struct formatter<wchar_t, wchar_t>;
+
+  template<> struct formatter<charT*, charT>;
+  template<> struct formatter<const charT*, charT>;
+  template<size_t N> struct formatter<const charT[N], charT>;
+  template<class traits, class Allocator>
+    struct formatter<basic_string<charT, traits, Allocator>, charT>;
+  template<class traits>
+    struct formatter<basic_string_view<charT, traits>, charT>;
+
+  // [format.parse.ctx], class template basic_format_parse_context
+  template<class charT>
+  class basic_format_parse_context {
+  public:
+    using char_type = charT;
+    using const_iterator = typename basic_string_view<charT>::const_iterator;
+    using iterator = const_iterator;
+
+  private:
+    iterator begin_;                                    // exposition only
+    iterator end_;                                      // exposition only
+    enum indexing { unknown, manual, automatic };       // exposition only
+    indexing indexing_;                                 // exposition only
+    size_t next_arg_id_;                                // exposition only
+    size_t num_args_;                                   // exposition only
+
+  public:
+    constexpr explicit basic_format_parse_context(basic_string_view<charT> fmt,
+                                                  size_t num_args = 0) noexcept;
+    basic_format_parse_context(const basic_format_parse_context&) = delete;
+    basic_format_parse_context& operator=(const basic_format_parse_context&) = delete;
+
+    constexpr const_iterator begin() const noexcept;
+    constexpr const_iterator end() const noexcept;
+    constexpr void advance_to(const_iterator it);
+
+    constexpr size_t next_arg_id();
+    constexpr void check_arg_id(size_t id);
+  };
+  using format_parse_context = basic_format_parse_context<char>;
+  using wformat_parse_context = basic_format_parse_context<wchar_t>;
+
+  // [format.arguments], arguments
+  // [format.arg], class template basic_format_arg
+  template<class Context>
+  class basic_format_arg {
+  public:
+    class handle;
+
+  private:
+    using char_type = typename Context::char_type;                              // exposition only
+
+    variant<monostate, bool, char_type,
+            int, unsigned int, long long int, unsigned long long int,
+            float, double, long double,
+            const char_type*, basic_string_view<char_type>,
+            const void*, handle> value;                                         // exposition only
+
+    template<class T> explicit basic_format_arg(const T& v) noexcept;           // exposition only
+    explicit basic_format_arg(float n) noexcept;                                // exposition only
+    explicit basic_format_arg(double n) noexcept;                               // exposition only
+    explicit basic_format_arg(long double n) noexcept;                          // exposition only
+    explicit basic_format_arg(const char_type* s);                              // exposition only
+
+    template<class traits>
+      explicit basic_format_arg(
+        basic_string_view<char_type, traits> s) noexcept;                       // exposition only
+
+    template<class traits, class Allocator>
+      explicit basic_format_arg(
+        const basic_string<char_type, traits, Allocator>& s) noexcept;          // exposition only
+
+    explicit basic_format_arg(nullptr_t) noexcept;                              // exposition only
+
+    template<class T>
+      explicit basic_format_arg(const T* p) noexcept;                           // exposition only
+
+  public:
+    basic_format_arg() noexcept;
+
+    explicit operator bool() const noexcept;
+  };
+
+  template<class Visitor, class Context>
+    see below visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg);
+
+  // [format.arg.store], class template format-arg-store
+  template<class Context, class... Args>
+  struct format-arg-store {      // exposition only
+    array<basic_format_arg<Context>, sizeof...(Args)> args;
+  };
+
+  template<class Context = format_context, class... Args>
+    format-arg-store<Context, Args...>
+      make_format_args(const Args&... args);
+  template<class... Args>
+    format-arg-store<wformat_context, Args...>
+      make_wformat_args(const Args&... args);
+
+  // [format.error], class format_error
+  class format_error : public runtime_error {
+  public:
+    explicit format_error(const string& what_arg);
+    explicit format_error(const char* what_arg);
+  };
+
+  // [format.parse.ctx], class template basic_format_parse_context
+  template<class charT>
+  class basic_format_parse_context {
+  public:
+    using char_type = charT;
+    using const_iterator = typename basic_string_view<charT>::const_iterator;
+    using iterator = const_iterator;
+
+  private:
+    iterator begin_;                                    // exposition only
+    iterator end_;                                      // exposition only
+    enum indexing { unknown, manual, automatic };       // exposition only
+    indexing indexing_;                                 // exposition only
+    size_t next_arg_id_;                                // exposition only
+    size_t num_args_;                                   // exposition only
+
+  public:
+    constexpr explicit basic_format_parse_context(basic_string_view<charT> fmt,
+                                                  size_t num_args = 0) noexcept;
+    basic_format_parse_context(const basic_format_parse_context&) = delete;
+    basic_format_parse_context& operator=(const basic_format_parse_context&) = delete;
+
+    constexpr const_iterator begin() const noexcept;
+    constexpr const_iterator end() const noexcept;
+    constexpr void advance_to(const_iterator it);
+
+    constexpr size_t next_arg_id();
+    constexpr void check_arg_id(size_t id);
+  };
+  using format_parse_context = basic_format_parse_context<char>;
+  using wformat_parse_context = basic_format_parse_context<wchar_t>;
+}
+
+*/
+
+// Make sure all feature-test macros are available.
+#include <version>
+// Enable the contents of the header only when libc++ was built with LIBCXX_ENABLE_INCOMPLETE_FEATURES.
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+
+#include <__config>
+#include <__debug>
+#include <__format/format_arg.h>
+#include <__format/format_args.h>
+#include <__format/format_context.h>
+#include <__format/format_error.h>
+#include <__format/format_fwd.h>
+#include <__format/format_parse_context.h>
+#include <__format/format_string.h>
+#include <__format/formatter.h>
+#include <__format/formatter_bool.h>
+#include <__format/formatter_char.h>
+#include <__format/formatter_integer.h>
+#include <__format/formatter_string.h>
+#include <__format/parser_std_format_spec.h>
+#include <__variant/monostate.h>
+#include <array>
+#include <concepts>
+#include <string>
+#include <string_view>
+#include <type_traits>
+
+#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+#include <locale>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// TODO FMT Evaluate which templates should be external templates. This
+// improves the efficiency of the header. However since the header is still
+// under heavy development and not all classes are stable it makes no sense
+// to do this optimization now.
+
+using format_args = basic_format_args<format_context>;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+using wformat_args = basic_format_args<wformat_context>;
+#endif
+
+template <class _OutIt, class _CharT>
+using format_args_t = basic_format_args<basic_format_context<_OutIt, _CharT>>;
+
+template <class _Context, class... _Args>
+struct _LIBCPP_TEMPLATE_VIS __format_arg_store {
+  // TODO FMT Use a built-in array.
+  array<basic_format_arg<_Context>, sizeof...(_Args)> __args;
+};
+
+template <class _Context = format_context, class... _Args>
+_LIBCPP_HIDE_FROM_ABI __format_arg_store<_Context, _Args...>
+make_format_args(const _Args&... __args) {
+  return {basic_format_arg<_Context>(__args)...};
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI __format_arg_store<wformat_context, _Args...>
+make_wformat_args(const _Args&... __args) {
+  return _VSTD::make_format_args<wformat_context>(__args...);
+}
+#endif
+
+namespace __format {
+
+template <class _Tp, class _CharT>
+requires(is_arithmetic_v<_Tp> &&
+         !same_as<_Tp, bool>) struct _LIBCPP_HIDE_FROM_ABI
+    __formatter_arithmetic {
+  _LIBCPP_HIDE_FROM_ABI
+  auto parse(auto& __parse_ctx) -> decltype(__parse_ctx.begin()) {
+    // TODO FMT Implement
+    return __parse_ctx.begin();
+  }
+
+  _LIBCPP_HIDE_FROM_ABI
+  auto format(_Tp __value, auto& __ctx) -> decltype(__ctx.out()) {
+    return __handle_format(__value, __ctx);
+  }
+
+private:
+  template <class _Uv>
+  _LIBCPP_HIDDEN static string
+  __convert(_Uv __value) requires(same_as<_CharT, char>) {
+    return _VSTD::to_string(__value);
+  }
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+  template <class _Uv>
+  _LIBCPP_HIDDEN static wstring
+  __convert(_Uv __value) requires(same_as<_CharT, wchar_t>) {
+    return _VSTD::to_wstring(__value);
+  }
+#endif
+
+  template <class _Uv>
+  _LIBCPP_HIDDEN auto __handle_format(_Uv __value, auto& __ctx)
+      -> decltype(__ctx.out())
+  {
+    // TODO FMT Implement using formatting arguments
+    // TODO FMT Improve PoC since using std::to_string is inefficient.
+    // Note the code doesn't use std::string::iterator since the unit tests
+    // test with debug iterators and they fail with strings created from
+    // std::to_string.
+    auto __str = __convert(__value);
+    auto __out_it = __ctx.out();
+    for (size_t __i = 0, __e = __str.size(); __i != __e; ++__i)
+      *__out_it++ = __str[__i];
+    return __out_it;
+  }
+};
+} // namespace __format
+
+// These specializations are helper stubs and not proper formatters.
+// TODO FMT Implement the proper formatter specializations.
+
+// Floating point types.
+// TODO FMT There are no replacements for the floating point stubs due to not
+// having floating point support in std::to_chars yet. These stubs aren't
+// removed since they are useful for developing the real versions.
+// Ultimately the stubs should be implemented properly and this code can be
+// removed.
+#if 0
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<float, _CharT>
+    : public __format::__formatter_arithmetic<float, _CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<double, _CharT>
+    : public __format::__formatter_arithmetic<double, _CharT> {};
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
+    formatter<long double, _CharT>
+    : public __format::__formatter_arithmetic<long double, _CharT> {};
+#endif
+
+namespace __format {
+
+template <class _CharT, class _ParseCtx, class _Ctx>
+_LIBCPP_HIDE_FROM_ABI const _CharT*
+__handle_replacement_field(const _CharT* __begin, const _CharT* __end,
+                           _ParseCtx& __parse_ctx, _Ctx& __ctx) {
+  __format::__parse_number_result __r =
+      __format::__parse_arg_id(__begin, __end, __parse_ctx);
+
+  switch (*__r.__ptr) {
+  case _CharT(':'):
+    // The arg-id has a format-specifier, advance the input to the format-spec.
+    __parse_ctx.advance_to(__r.__ptr + 1);
+    break;
+  case _CharT('}'):
+    // The arg-id has no format-specifier.
+    __parse_ctx.advance_to(__r.__ptr);
+    break;
+  default:
+    __throw_format_error(
+        "The replacement field arg-id should terminate at a ':' or '}'");
+  }
+
+  _VSTD::visit_format_arg(
+      [&](auto __arg) {
+        if constexpr (same_as<decltype(__arg), monostate>)
+          __throw_format_error("Argument index out of bounds");
+        else {
+          formatter<decltype(__arg), _CharT> __formatter;
+          __parse_ctx.advance_to(__formatter.parse(__parse_ctx));
+          __ctx.advance_to(__formatter.format(__arg, __ctx));
+        }
+      },
+      __ctx.arg(__r.__value));
+
+  __begin = __parse_ctx.begin();
+  if (__begin == __end || *__begin != _CharT('}'))
+    __throw_format_error("The replacement field misses a terminating '}'");
+
+  return ++__begin;
+}
+
+template <class _ParseCtx, class _Ctx>
+_LIBCPP_HIDE_FROM_ABI typename _Ctx::iterator
+__vformat_to(_ParseCtx&& __parse_ctx, _Ctx&& __ctx) {
+  using _CharT = typename _ParseCtx::char_type;
+  static_assert(same_as<typename _Ctx::char_type, _CharT>);
+
+  const _CharT* __begin = __parse_ctx.begin();
+  const _CharT* __end = __parse_ctx.end();
+  typename _Ctx::iterator __out_it = __ctx.out();
+  while (__begin != __end) {
+    switch (*__begin) {
+    case _CharT('{'):
+      ++__begin;
+      if (__begin == __end)
+        __throw_format_error("The format string terminates at a '{'");
+
+      if (*__begin != _CharT('{')) [[likely]] {
+        __ctx.advance_to(_VSTD::move(__out_it));
+        __begin =
+            __handle_replacement_field(__begin, __end, __parse_ctx, __ctx);
+        __out_it = __ctx.out();
+
+        // The output is written and __begin points to the next character. So
+        // start the next iteration.
+        continue;
+      }
+      // The string is an escape character.
+      break;
+
+    case _CharT('}'):
+      ++__begin;
+      if (__begin == __end || *__begin != _CharT('}'))
+        __throw_format_error(
+            "The format string contains an invalid escape sequence");
+
+      break;
+    }
+
+    // Copy the character to the output verbatim.
+    *__out_it++ = *__begin++;
+  }
+  return __out_it;
+}
+
+} // namespace __format
+
+template <class _OutIt, class _CharT>
+requires(output_iterator<_OutIt, const _CharT&>) _LIBCPP_HIDE_FROM_ABI _OutIt
+    __vformat_to(_OutIt __out_it, basic_string_view<_CharT> __fmt,
+                 format_args_t<type_identity_t<_OutIt>, _CharT> __args) {
+  return __format::__vformat_to(
+      basic_format_parse_context{__fmt, __args.__size()},
+      _VSTD::__format_context_create(_VSTD::move(__out_it), __args));
+}
+
+template <output_iterator<const char&> _OutIt>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
+vformat_to(_OutIt __out_it, string_view __fmt,
+           format_args_t<type_identity_t<_OutIt>, char> __args) {
+  return _VSTD::__vformat_to(_VSTD::move(__out_it), __fmt, __args);
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <output_iterator<const wchar_t&> _OutIt>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
+vformat_to(_OutIt __out_it, wstring_view __fmt,
+           format_args_t<type_identity_t<_OutIt>, wchar_t> __args) {
+  return _VSTD::__vformat_to(_VSTD::move(__out_it), __fmt, __args);
+}
+#endif
+
+template <output_iterator<const char&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
+format_to(_OutIt __out_it, string_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat_to(
+      _VSTD::move(__out_it), __fmt,
+      _VSTD::make_format_args<basic_format_context<_OutIt, char>>(__args...));
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <output_iterator<const wchar_t&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
+format_to(_OutIt __out_it, wstring_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat_to(
+      _VSTD::move(__out_it), __fmt,
+      _VSTD::make_format_args<basic_format_context<_OutIt, wchar_t>>(
+          __args...));
+}
+#endif
+
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT string
+vformat(string_view __fmt, format_args __args) {
+  string __res;
+  _VSTD::vformat_to(_VSTD::back_inserter(__res), __fmt, __args);
+  return __res;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT wstring
+vformat(wstring_view __fmt, wformat_args __args) {
+  wstring __res;
+  _VSTD::vformat_to(_VSTD::back_inserter(__res), __fmt, __args);
+  return __res;
+}
+#endif
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT string
+format(string_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat(__fmt, _VSTD::make_format_args(__args...));
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT wstring
+format(wstring_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat(__fmt, _VSTD::make_wformat_args(__args...));
+}
+#endif
+
+template <class _OutIt>
+struct _LIBCPP_TEMPLATE_VIS format_to_n_result {
+  _OutIt out;
+  iter_difference_t<_OutIt> size;
+};
+
+template <output_iterator<const char&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT format_to_n_result<_OutIt>
+format_to_n(_OutIt __out_it, iter_difference_t<_OutIt> __n, string_view __fmt,
+            const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  string __str = _VSTD::vformat(__fmt, _VSTD::make_format_args(__args...));
+  iter_difference_t<_OutIt> __s = __str.size();
+  iter_difference_t<_OutIt> __m =
+      _VSTD::clamp(__n, iter_difference_t<_OutIt>(0), __s);
+  __out_it = _VSTD::copy_n(__str.begin(), __m, _VSTD::move(__out_it));
+  return {_VSTD::move(__out_it), __s};
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <output_iterator<const wchar_t&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT format_to_n_result<_OutIt>
+format_to_n(_OutIt __out_it, iter_difference_t<_OutIt> __n, wstring_view __fmt,
+            const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  wstring __str = _VSTD::vformat(__fmt, _VSTD::make_wformat_args(__args...));
+  iter_difference_t<_OutIt> __s = __str.size();
+  iter_difference_t<_OutIt> __m =
+      _VSTD::clamp(__n, iter_difference_t<_OutIt>(0), __s);
+  __out_it = _VSTD::copy_n(__str.begin(), __m, _VSTD::move(__out_it));
+  return {_VSTD::move(__out_it), __s};
+}
+#endif
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT size_t
+formatted_size(string_view __fmt, const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  return _VSTD::vformat(__fmt, _VSTD::make_format_args(__args...)).size();
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT size_t
+formatted_size(wstring_view __fmt, const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  return _VSTD::vformat(__fmt, _VSTD::make_wformat_args(__args...)).size();
+}
+#endif
+
+#ifndef _LIBCPP_HAS_NO_LOCALIZATION
+
+template <class _OutIt, class _CharT>
+requires(output_iterator<_OutIt, const _CharT&>) _LIBCPP_HIDE_FROM_ABI _OutIt
+    __vformat_to(_OutIt __out_it, locale __loc, basic_string_view<_CharT> __fmt,
+                 format_args_t<type_identity_t<_OutIt>, _CharT> __args) {
+  return __format::__vformat_to(
+      basic_format_parse_context{__fmt, __args.__size()},
+      _VSTD::__format_context_create(_VSTD::move(__out_it), __args,
+                                     _VSTD::move(__loc)));
+}
+
+template <output_iterator<const char&> _OutIt>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
+vformat_to(_OutIt __out_it, locale __loc, string_view __fmt,
+           format_args_t<type_identity_t<_OutIt>, char> __args) {
+  return _VSTD::__vformat_to(_VSTD::move(__out_it), _VSTD::move(__loc), __fmt,
+                             __args);
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <output_iterator<const wchar_t&> _OutIt>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
+vformat_to(_OutIt __out_it, locale __loc, wstring_view __fmt,
+           format_args_t<type_identity_t<_OutIt>, wchar_t> __args) {
+  return _VSTD::__vformat_to(_VSTD::move(__out_it), _VSTD::move(__loc), __fmt,
+                             __args);
+}
+#endif
+
+template <output_iterator<const char&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt format_to(
+    _OutIt __out_it, locale __loc, string_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat_to(
+      _VSTD::move(__out_it), _VSTD::move(__loc), __fmt,
+      _VSTD::make_format_args<basic_format_context<_OutIt, char>>(__args...));
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <output_iterator<const wchar_t&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt format_to(
+    _OutIt __out_it, locale __loc, wstring_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat_to(
+      _VSTD::move(__out_it), _VSTD::move(__loc), __fmt,
+      _VSTD::make_format_args<basic_format_context<_OutIt, wchar_t>>(
+          __args...));
+}
+#endif
+
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT string
+vformat(locale __loc, string_view __fmt, format_args __args) {
+  string __res;
+  _VSTD::vformat_to(_VSTD::back_inserter(__res), _VSTD::move(__loc), __fmt,
+                    __args);
+  return __res;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT wstring
+vformat(locale __loc, wstring_view __fmt, wformat_args __args) {
+  wstring __res;
+  _VSTD::vformat_to(_VSTD::back_inserter(__res), _VSTD::move(__loc), __fmt,
+                    __args);
+  return __res;
+}
+#endif
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT string
+format(locale __loc, string_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat(_VSTD::move(__loc), __fmt,
+                        _VSTD::make_format_args(__args...));
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT wstring
+format(locale __loc, wstring_view __fmt, const _Args&... __args) {
+  return _VSTD::vformat(_VSTD::move(__loc), __fmt,
+                        _VSTD::make_wformat_args(__args...));
+}
+#endif
+
+template <output_iterator<const char&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT format_to_n_result<_OutIt>
+format_to_n(_OutIt __out_it, iter_difference_t<_OutIt> __n, locale __loc,
+            string_view __fmt, const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  string __str = _VSTD::vformat(_VSTD::move(__loc), __fmt,
+                                _VSTD::make_format_args(__args...));
+  iter_difference_t<_OutIt> __s = __str.size();
+  iter_difference_t<_OutIt> __m =
+      _VSTD::clamp(__n, iter_difference_t<_OutIt>(0), __s);
+  __out_it = _VSTD::copy_n(__str.begin(), __m, _VSTD::move(__out_it));
+  return {_VSTD::move(__out_it), __s};
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <output_iterator<const wchar_t&> _OutIt, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT format_to_n_result<_OutIt>
+format_to_n(_OutIt __out_it, iter_difference_t<_OutIt> __n, locale __loc,
+            wstring_view __fmt, const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  wstring __str = _VSTD::vformat(_VSTD::move(__loc), __fmt,
+                                 _VSTD::make_wformat_args(__args...));
+  iter_difference_t<_OutIt> __s = __str.size();
+  iter_difference_t<_OutIt> __m =
+      _VSTD::clamp(__n, iter_difference_t<_OutIt>(0), __s);
+  __out_it = _VSTD::copy_n(__str.begin(), __m, _VSTD::move(__out_it));
+  return {_VSTD::move(__out_it), __s};
+}
+#endif
+
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT size_t
+formatted_size(locale __loc, string_view __fmt, const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  return _VSTD::vformat(_VSTD::move(__loc), __fmt,
+                        _VSTD::make_format_args(__args...))
+      .size();
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT size_t
+formatted_size(locale __loc, wstring_view __fmt, const _Args&... __args) {
+  // TODO FMT Improve PoC: using std::string is inefficient.
+  return _VSTD::vformat(_VSTD::move(__loc), __fmt,
+                        _VSTD::make_wformat_args(__args...))
+      .size();
+}
+#endif
+
+#endif // _LIBCPP_HAS_NO_LOCALIZATION
+
+#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+
+#endif // _LIBCPP_FORMAT
diff --git a/contrib/libs/cxxsupp/libcxx/include/forward_list b/contrib/libs/cxxsupp/libcxx/include/forward_list
new file mode 100644
index 00000000000..3454a784a1c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/forward_list
@@ -0,0 +1,1788 @@
+// -*- C++ -*-
+//===----------------------- forward_list ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_FORWARD_LIST
+#define _LIBCPP_FORWARD_LIST
+
+/*
+    forward_list synopsis
+
+namespace std
+{
+
+template <class T, class Allocator = allocator<T>>
+class forward_list
+{
+public:
+    typedef T         value_type;
+    typedef Allocator allocator_type;
+
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    typedef typename allocator_traits<allocator_type>::pointer         pointer;
+    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
+    typedef typename allocator_traits<allocator_type>::size_type       size_type;
+    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
+
+    typedef <details> iterator;
+    typedef <details> const_iterator;
+
+    forward_list()
+        noexcept(is_nothrow_default_constructible<allocator_type>::value);
+    explicit forward_list(const allocator_type& a);
+    explicit forward_list(size_type n);
+    explicit forward_list(size_type n, const allocator_type& a); // C++14
+    forward_list(size_type n, const value_type& v);
+    forward_list(size_type n, const value_type& v, const allocator_type& a);
+    template <class InputIterator>
+        forward_list(InputIterator first, InputIterator last);
+    template <class InputIterator>
+        forward_list(InputIterator first, InputIterator last, const allocator_type& a);
+    forward_list(const forward_list& x);
+    forward_list(const forward_list& x, const allocator_type& a);
+    forward_list(forward_list&& x)
+        noexcept(is_nothrow_move_constructible<allocator_type>::value);
+    forward_list(forward_list&& x, const allocator_type& a);
+    forward_list(initializer_list<value_type> il);
+    forward_list(initializer_list<value_type> il, const allocator_type& a);
+
+    ~forward_list();
+
+    forward_list& operator=(const forward_list& x);
+    forward_list& operator=(forward_list&& x)
+        noexcept(
+             allocator_type::propagate_on_container_move_assignment::value &&
+             is_nothrow_move_assignable<allocator_type>::value);
+    forward_list& operator=(initializer_list<value_type> il);
+
+    template <class InputIterator>
+        void assign(InputIterator first, InputIterator last);
+    void assign(size_type n, const value_type& v);
+    void assign(initializer_list<value_type> il);
+
+    allocator_type get_allocator() const noexcept;
+
+    iterator       begin() noexcept;
+    const_iterator begin() const noexcept;
+    iterator       end() noexcept;
+    const_iterator end() const noexcept;
+
+    const_iterator cbegin() const noexcept;
+    const_iterator cend() const noexcept;
+
+    iterator       before_begin() noexcept;
+    const_iterator before_begin() const noexcept;
+    const_iterator cbefore_begin() const noexcept;
+
+    bool empty() const noexcept;
+    size_type max_size() const noexcept;
+
+    reference       front();
+    const_reference front() const;
+
+    template <class... Args> reference emplace_front(Args&&... args);  // reference in C++17
+    void push_front(const value_type& v);
+    void push_front(value_type&& v);
+
+    void pop_front();
+
+    template <class... Args>
+        iterator emplace_after(const_iterator p, Args&&... args);
+    iterator insert_after(const_iterator p, const value_type& v);
+    iterator insert_after(const_iterator p, value_type&& v);
+    iterator insert_after(const_iterator p, size_type n, const value_type& v);
+    template <class InputIterator>
+        iterator insert_after(const_iterator p,
+                              InputIterator first, InputIterator last);
+    iterator insert_after(const_iterator p, initializer_list<value_type> il);
+
+    iterator erase_after(const_iterator p);
+    iterator erase_after(const_iterator first, const_iterator last);
+
+    void swap(forward_list& x)
+        noexcept(allocator_traits<allocator_type>::is_always_equal::value);  // C++17
+
+    void resize(size_type n);
+    void resize(size_type n, const value_type& v);
+    void clear() noexcept;
+
+    void splice_after(const_iterator p, forward_list& x);
+    void splice_after(const_iterator p, forward_list&& x);
+    void splice_after(const_iterator p, forward_list& x, const_iterator i);
+    void splice_after(const_iterator p, forward_list&& x, const_iterator i);
+    void splice_after(const_iterator p, forward_list& x,
+                      const_iterator first, const_iterator last);
+    void splice_after(const_iterator p, forward_list&& x,
+                      const_iterator first, const_iterator last);
+    size_type remove(const value_type& v);           // void before C++20
+    template <class Predicate>
+      size_type remove_if(Predicate pred);           // void before C++20
+    size_type unique();                              // void before C++20
+    template <class BinaryPredicate>
+      size_type unique(BinaryPredicate binary_pred); // void before C++20
+    void merge(forward_list& x);
+    void merge(forward_list&& x);
+    template <class Compare> void merge(forward_list& x, Compare comp);
+    template <class Compare> void merge(forward_list&& x, Compare comp);
+    void sort();
+    template <class Compare> void sort(Compare comp);
+    void reverse() noexcept;
+};
+
+
+template <class InputIterator, class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
+    forward_list(InputIterator, InputIterator, Allocator = Allocator())
+    -> forward_list<typename iterator_traits<InputIterator>::value_type, Allocator>;  // C++17
+
+template <class T, class Allocator>
+    bool operator==(const forward_list<T, Allocator>& x,
+                    const forward_list<T, Allocator>& y);
+
+template <class T, class Allocator>
+    bool operator< (const forward_list<T, Allocator>& x,
+                    const forward_list<T, Allocator>& y);
+
+template <class T, class Allocator>
+    bool operator!=(const forward_list<T, Allocator>& x,
+                    const forward_list<T, Allocator>& y);
+
+template <class T, class Allocator>
+    bool operator> (const forward_list<T, Allocator>& x,
+                    const forward_list<T, Allocator>& y);
+
+template <class T, class Allocator>
+    bool operator>=(const forward_list<T, Allocator>& x,
+                    const forward_list<T, Allocator>& y);
+
+template <class T, class Allocator>
+    bool operator<=(const forward_list<T, Allocator>& x,
+                    const forward_list<T, Allocator>& y);
+
+template <class T, class Allocator>
+    void swap(forward_list<T, Allocator>& x, forward_list<T, Allocator>& y)
+         noexcept(noexcept(x.swap(y)));
+
+template <class T, class Allocator, class U>
+    typename forward_list<T, Allocator>::size_type
+    erase(forward_list<T, Allocator>& c, const U& value);       // C++20
+template <class T, class Allocator, class Predicate>
+    typename forward_list<T, Allocator>::size_type
+    erase_if(forward_list<T, Allocator>& c, Predicate pred);    // C++20
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__utility/forward.h>
+#include <algorithm>
+#include <initializer_list>
+#include <iterator>
+#include <limits>
+#include <memory>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class _VoidPtr> struct __forward_list_node;
+template <class _NodePtr> struct __forward_begin_node;
+
+
+template <class>
+struct __forward_list_node_value_type;
+
+template <class _Tp, class _VoidPtr>
+struct __forward_list_node_value_type<__forward_list_node<_Tp, _VoidPtr> > {
+  typedef _Tp type;
+};
+
+template <class _NodePtr>
+struct __forward_node_traits {
+
+  typedef typename remove_cv<
+        typename pointer_traits<_NodePtr>::element_type>::type  __node;
+  typedef typename __forward_list_node_value_type<__node>::type __node_value_type;
+  typedef _NodePtr                                              __node_pointer;
+  typedef __forward_begin_node<_NodePtr>                        __begin_node;
+  typedef typename __rebind_pointer<_NodePtr, __begin_node>::type
+                                                                __begin_node_pointer;
+  typedef typename __rebind_pointer<_NodePtr, void>::type       __void_pointer;
+
+#if defined(_LIBCPP_ABI_FORWARD_LIST_REMOVE_NODE_POINTER_UB)
+  typedef __begin_node_pointer __iter_node_pointer;
+#else
+  typedef typename conditional<
+          is_pointer<__void_pointer>::value,
+          __begin_node_pointer,
+          __node_pointer
+    >::type __iter_node_pointer;
+#endif
+
+  typedef typename conditional<
+          is_same<__iter_node_pointer, __node_pointer>::value,
+          __begin_node_pointer,
+          __node_pointer
+    >::type __non_iter_node_pointer;
+
+  _LIBCPP_INLINE_VISIBILITY
+  static __iter_node_pointer __as_iter_node(__iter_node_pointer __p) {
+      return __p;
+  }
+  _LIBCPP_INLINE_VISIBILITY
+  static __iter_node_pointer __as_iter_node(__non_iter_node_pointer __p) {
+      return static_cast<__iter_node_pointer>(static_cast<__void_pointer>(__p));
+  }
+};
+
+template <class _NodePtr>
+struct __forward_begin_node
+{
+    typedef _NodePtr pointer;
+    typedef typename __rebind_pointer<_NodePtr, __forward_begin_node>::type __begin_node_pointer;
+
+    pointer __next_;
+
+    _LIBCPP_INLINE_VISIBILITY __forward_begin_node() : __next_(nullptr) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __begin_node_pointer __next_as_begin() const {
+        return static_cast<__begin_node_pointer>(__next_);
+    }
+};
+
+template <class _Tp, class _VoidPtr>
+struct _LIBCPP_HIDDEN __begin_node_of
+{
+    typedef __forward_begin_node<
+        typename __rebind_pointer<_VoidPtr, __forward_list_node<_Tp, _VoidPtr> >::type
+    > type;
+};
+
+template <class _Tp, class _VoidPtr>
+struct _LIBCPP_STANDALONE_DEBUG __forward_list_node
+    : public __begin_node_of<_Tp, _VoidPtr>::type
+{
+    typedef _Tp value_type;
+
+    value_type __value_;
+};
+
+
+template <class _Tp, class _Alloc = allocator<_Tp> > class _LIBCPP_TEMPLATE_VIS forward_list;
+template<class _NodeConstPtr> class _LIBCPP_TEMPLATE_VIS __forward_list_const_iterator;
+
+template <class _NodePtr>
+class _LIBCPP_TEMPLATE_VIS __forward_list_iterator
+{
+    typedef __forward_node_traits<_NodePtr>         __traits;
+    typedef typename __traits::__node_pointer       __node_pointer;
+    typedef typename __traits::__begin_node_pointer __begin_node_pointer;
+    typedef typename __traits::__iter_node_pointer  __iter_node_pointer;
+    typedef typename __traits::__void_pointer       __void_pointer;
+
+    __iter_node_pointer __ptr_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __begin_node_pointer __get_begin() const {
+        return static_cast<__begin_node_pointer>(
+                static_cast<__void_pointer>(__ptr_));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __node_pointer __get_unsafe_node_pointer() const {
+        return static_cast<__node_pointer>(
+                static_cast<__void_pointer>(__ptr_));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __forward_list_iterator(nullptr_t) _NOEXCEPT : __ptr_(nullptr) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __forward_list_iterator(__begin_node_pointer __p) _NOEXCEPT
+        : __ptr_(__traits::__as_iter_node(__p)) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __forward_list_iterator(__node_pointer __p) _NOEXCEPT
+        : __ptr_(__traits::__as_iter_node(__p)) {}
+
+    template<class, class> friend class _LIBCPP_TEMPLATE_VIS forward_list;
+    template<class> friend class _LIBCPP_TEMPLATE_VIS __forward_list_const_iterator;
+
+public:
+    typedef forward_iterator_tag                              iterator_category;
+    typedef typename __traits::__node_value_type              value_type;
+    typedef value_type&                                       reference;
+    typedef typename pointer_traits<__node_pointer>::difference_type
+                                                              difference_type;
+    typedef typename __rebind_pointer<__node_pointer, value_type>::type pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_iterator() _NOEXCEPT : __ptr_(nullptr) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {return __get_unsafe_node_pointer()->__value_;}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {
+        return pointer_traits<pointer>::pointer_to(__get_unsafe_node_pointer()->__value_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_iterator& operator++()
+    {
+        __ptr_ = __traits::__as_iter_node(__ptr_->__next_);
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_iterator operator++(int)
+    {
+        __forward_list_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __forward_list_iterator& __x,
+                    const __forward_list_iterator& __y)
+        {return __x.__ptr_ == __y.__ptr_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __forward_list_iterator& __x,
+                    const __forward_list_iterator& __y)
+        {return !(__x == __y);}
+};
+
+template <class _NodeConstPtr>
+class _LIBCPP_TEMPLATE_VIS __forward_list_const_iterator
+{
+    static_assert((!is_const<typename pointer_traits<_NodeConstPtr>::element_type>::value), "");
+    typedef _NodeConstPtr _NodePtr;
+
+    typedef __forward_node_traits<_NodePtr>         __traits;
+    typedef typename __traits::__node               __node;
+    typedef typename __traits::__node_pointer       __node_pointer;
+    typedef typename __traits::__begin_node_pointer __begin_node_pointer;
+    typedef typename __traits::__iter_node_pointer  __iter_node_pointer;
+    typedef typename __traits::__void_pointer       __void_pointer;
+
+    __iter_node_pointer __ptr_;
+
+    __begin_node_pointer __get_begin() const {
+        return static_cast<__begin_node_pointer>(
+                static_cast<__void_pointer>(__ptr_));
+    }
+    __node_pointer __get_unsafe_node_pointer() const {
+        return static_cast<__node_pointer>(
+                static_cast<__void_pointer>(__ptr_));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __forward_list_const_iterator(nullptr_t) _NOEXCEPT
+        : __ptr_(nullptr) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __forward_list_const_iterator(__begin_node_pointer __p) _NOEXCEPT
+        : __ptr_(__traits::__as_iter_node(__p)) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __forward_list_const_iterator(__node_pointer __p) _NOEXCEPT
+        : __ptr_(__traits::__as_iter_node(__p)) {}
+
+
+    template<class, class> friend class forward_list;
+
+public:
+    typedef forward_iterator_tag                              iterator_category;
+    typedef typename __traits::__node_value_type              value_type;
+    typedef const value_type&                                 reference;
+    typedef typename pointer_traits<__node_pointer>::difference_type
+                                                              difference_type;
+    typedef typename __rebind_pointer<__node_pointer, const value_type>::type
+                                                              pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_const_iterator() _NOEXCEPT : __ptr_(nullptr) {}
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_const_iterator(__forward_list_iterator<__node_pointer> __p) _NOEXCEPT
+        : __ptr_(__p.__ptr_) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {return __get_unsafe_node_pointer()->__value_;}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {return pointer_traits<pointer>::pointer_to(
+                __get_unsafe_node_pointer()->__value_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_const_iterator& operator++()
+    {
+        __ptr_ = __traits::__as_iter_node(__ptr_->__next_);
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_const_iterator operator++(int)
+    {
+        __forward_list_const_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __forward_list_const_iterator& __x,
+                    const __forward_list_const_iterator& __y)
+        {return __x.__ptr_ == __y.__ptr_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __forward_list_const_iterator& __x,
+                           const __forward_list_const_iterator& __y)
+        {return !(__x == __y);}
+};
+
+template <class _Tp, class _Alloc>
+class __forward_list_base
+{
+protected:
+    typedef _Tp    value_type;
+    typedef _Alloc allocator_type;
+
+    typedef typename allocator_traits<allocator_type>::void_pointer  void_pointer;
+    typedef __forward_list_node<value_type, void_pointer>            __node;
+    typedef typename __begin_node_of<value_type, void_pointer>::type __begin_node;
+    typedef typename __rebind_alloc_helper<allocator_traits<allocator_type>, __node>::type __node_allocator;
+    typedef allocator_traits<__node_allocator>        __node_traits;
+    typedef typename __node_traits::pointer           __node_pointer;
+
+    typedef typename __rebind_alloc_helper<
+        allocator_traits<allocator_type>, __begin_node
+    >::type                                           __begin_node_allocator;
+    typedef typename allocator_traits<__begin_node_allocator>::pointer
+                                                      __begin_node_pointer;
+
+    static_assert((!is_same<allocator_type, __node_allocator>::value),
+                  "internal allocator type must differ from user-specified "
+                  "type; otherwise overload resolution breaks");
+
+    __compressed_pair<__begin_node, __node_allocator> __before_begin_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __begin_node_pointer        __before_begin() _NOEXCEPT
+        {return pointer_traits<__begin_node_pointer>::pointer_to(__before_begin_.first());}
+    _LIBCPP_INLINE_VISIBILITY
+    __begin_node_pointer __before_begin() const _NOEXCEPT
+        {return pointer_traits<__begin_node_pointer>::pointer_to(const_cast<__begin_node&>(__before_begin_.first()));}
+
+    _LIBCPP_INLINE_VISIBILITY
+          __node_allocator& __alloc() _NOEXCEPT
+            {return __before_begin_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    const __node_allocator& __alloc() const _NOEXCEPT
+        {return __before_begin_.second();}
+
+    typedef __forward_list_iterator<__node_pointer>             iterator;
+    typedef __forward_list_const_iterator<__node_pointer>       const_iterator;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_base()
+        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)
+        : __before_begin_(__begin_node(), __default_init_tag()) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __forward_list_base(const allocator_type& __a)
+        : __before_begin_(__begin_node(), __node_allocator(__a)) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __forward_list_base(const __node_allocator& __a)
+        : __before_begin_(__begin_node(), __a) {}
+#ifndef _LIBCPP_CXX03_LANG
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_base(__forward_list_base&& __x)
+        _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    __forward_list_base(__forward_list_base&& __x, const allocator_type& __a);
+#endif // _LIBCPP_CXX03_LANG
+
+private:
+    __forward_list_base(const __forward_list_base&);
+    __forward_list_base& operator=(const __forward_list_base&);
+
+public:
+    ~__forward_list_base();
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __forward_list_base& __x)
+        {__copy_assign_alloc(__x, integral_constant<bool,
+              __node_traits::propagate_on_container_copy_assignment::value>());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__forward_list_base& __x)
+        _NOEXCEPT_(!__node_traits::propagate_on_container_move_assignment::value ||
+                   is_nothrow_move_assignable<__node_allocator>::value)
+        {__move_assign_alloc(__x, integral_constant<bool,
+              __node_traits::propagate_on_container_move_assignment::value>());}
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(__forward_list_base& __x)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT;
+#else
+        _NOEXCEPT_(!__node_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<__node_allocator>::value);
+#endif
+protected:
+    void clear() _NOEXCEPT;
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __forward_list_base&, false_type) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __forward_list_base& __x, true_type)
+    {
+        if (__alloc() != __x.__alloc())
+            clear();
+        __alloc() = __x.__alloc();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__forward_list_base&, false_type) _NOEXCEPT
+        {}
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__forward_list_base& __x, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value)
+        {__alloc() = _VSTD::move(__x.__alloc());}
+};
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+inline
+__forward_list_base<_Tp, _Alloc>::__forward_list_base(__forward_list_base&& __x)
+        _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value)
+    : __before_begin_(_VSTD::move(__x.__before_begin_))
+{
+    __x.__before_begin()->__next_ = nullptr;
+}
+
+template <class _Tp, class _Alloc>
+inline
+__forward_list_base<_Tp, _Alloc>::__forward_list_base(__forward_list_base&& __x,
+                                                      const allocator_type& __a)
+    : __before_begin_(__begin_node(), __node_allocator(__a))
+{
+    if (__alloc() == __x.__alloc())
+    {
+        __before_begin()->__next_ = __x.__before_begin()->__next_;
+        __x.__before_begin()->__next_ = nullptr;
+    }
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+__forward_list_base<_Tp, _Alloc>::~__forward_list_base()
+{
+    clear();
+}
+
+template <class _Tp, class _Alloc>
+inline
+void
+__forward_list_base<_Tp, _Alloc>::swap(__forward_list_base& __x)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT
+#else
+        _NOEXCEPT_(!__node_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<__node_allocator>::value)
+#endif
+{
+    _VSTD::__swap_allocator(__alloc(), __x.__alloc(),
+            integral_constant<bool, __node_traits::propagate_on_container_swap::value>());
+    using _VSTD::swap;
+    swap(__before_begin()->__next_, __x.__before_begin()->__next_);
+}
+
+template <class _Tp, class _Alloc>
+void
+__forward_list_base<_Tp, _Alloc>::clear() _NOEXCEPT
+{
+    __node_allocator& __a = __alloc();
+    for (__node_pointer __p = __before_begin()->__next_; __p != nullptr;)
+    {
+        __node_pointer __next = __p->__next_;
+        __node_traits::destroy(__a, _VSTD::addressof(__p->__value_));
+        __node_traits::deallocate(__a, __p, 1);
+        __p = __next;
+    }
+    __before_begin()->__next_ = nullptr;
+}
+
+template <class _Tp, class _Alloc /*= allocator<_Tp>*/>
+class _LIBCPP_TEMPLATE_VIS forward_list
+    : private __forward_list_base<_Tp, _Alloc>
+{
+    typedef __forward_list_base<_Tp, _Alloc> base;
+    typedef typename base::__node_allocator  __node_allocator;
+    typedef typename base::__node               __node;
+    typedef typename base::__node_traits        __node_traits;
+    typedef typename base::__node_pointer       __node_pointer;
+    typedef typename base::__begin_node_pointer __begin_node_pointer;
+
+public:
+    typedef _Tp    value_type;
+    typedef _Alloc allocator_type;
+
+    static_assert((is_same<typename allocator_type::value_type, value_type>::value),
+                  "Allocator::value_type must be same type as value_type");
+
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    typedef typename allocator_traits<allocator_type>::pointer         pointer;
+    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
+    typedef typename allocator_traits<allocator_type>::size_type       size_type;
+    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
+
+    typedef typename base::iterator       iterator;
+    typedef typename base::const_iterator const_iterator;
+#if _LIBCPP_STD_VER > 17
+    typedef size_type                                __remove_return_type;
+#else
+    typedef void                                     __remove_return_type;
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    forward_list()
+        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)
+        {} // = default;
+    _LIBCPP_INLINE_VISIBILITY
+    explicit forward_list(const allocator_type& __a);
+    explicit forward_list(size_type __n);
+#if _LIBCPP_STD_VER > 11
+    explicit forward_list(size_type __n, const allocator_type& __a);
+#endif
+    forward_list(size_type __n, const value_type& __v);
+    forward_list(size_type __n, const value_type& __v, const allocator_type& __a);
+    template <class _InputIterator>
+        forward_list(_InputIterator __f, _InputIterator __l,
+                     typename enable_if<
+                       __is_cpp17_input_iterator<_InputIterator>::value
+                     >::type* = nullptr);
+    template <class _InputIterator>
+        forward_list(_InputIterator __f, _InputIterator __l,
+                     const allocator_type& __a,
+                     typename enable_if<
+                       __is_cpp17_input_iterator<_InputIterator>::value
+                     >::type* = nullptr);
+    forward_list(const forward_list& __x);
+    forward_list(const forward_list& __x, const __identity_t<allocator_type>& __a);
+
+    forward_list& operator=(const forward_list& __x);
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    forward_list(forward_list&& __x)
+        _NOEXCEPT_(is_nothrow_move_constructible<base>::value)
+        : base(_VSTD::move(__x)) {}
+    forward_list(forward_list&& __x, const __identity_t<allocator_type>& __a);
+
+    forward_list(initializer_list<value_type> __il);
+    forward_list(initializer_list<value_type> __il, const allocator_type& __a);
+
+    _LIBCPP_INLINE_VISIBILITY
+    forward_list& operator=(forward_list&& __x)
+        _NOEXCEPT_(
+             __node_traits::propagate_on_container_move_assignment::value &&
+             is_nothrow_move_assignable<allocator_type>::value);
+
+    _LIBCPP_INLINE_VISIBILITY
+    forward_list& operator=(initializer_list<value_type> __il);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void assign(initializer_list<value_type> __il);
+#endif // _LIBCPP_CXX03_LANG
+
+    // ~forward_list() = default;
+
+    template <class _InputIterator>
+        typename enable_if
+        <
+            __is_cpp17_input_iterator<_InputIterator>::value,
+            void
+        >::type
+        assign(_InputIterator __f, _InputIterator __l);
+    void assign(size_type __n, const value_type& __v);
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT
+        {return allocator_type(base::__alloc());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       begin() _NOEXCEPT
+        {return       iterator(base::__before_begin()->__next_);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const _NOEXCEPT
+        {return const_iterator(base::__before_begin()->__next_);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       end() _NOEXCEPT
+        {return       iterator(nullptr);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end() const _NOEXCEPT
+        {return const_iterator(nullptr);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin() const _NOEXCEPT
+        {return const_iterator(base::__before_begin()->__next_);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend() const _NOEXCEPT
+        {return const_iterator(nullptr);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       before_begin() _NOEXCEPT
+        {return       iterator(base::__before_begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator before_begin() const _NOEXCEPT
+        {return const_iterator(base::__before_begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbefore_begin() const _NOEXCEPT
+        {return const_iterator(base::__before_begin());}
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT
+        {return base::__before_begin()->__next_ == nullptr;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT {
+        return _VSTD::min<size_type>(
+            __node_traits::max_size(base::__alloc()),
+            numeric_limits<difference_type>::max());
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference       front()       {return base::__before_begin()->__next_->__value_;}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference front() const {return base::__before_begin()->__next_->__value_;}
+
+#ifndef _LIBCPP_CXX03_LANG
+#if _LIBCPP_STD_VER > 14
+    template <class... _Args> reference emplace_front(_Args&&... __args);
+#else
+    template <class... _Args> void      emplace_front(_Args&&... __args);
+#endif
+    void push_front(value_type&& __v);
+#endif // _LIBCPP_CXX03_LANG
+    void push_front(const value_type& __v);
+
+    void pop_front();
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class... _Args>
+        iterator emplace_after(const_iterator __p, _Args&&... __args);
+
+    iterator insert_after(const_iterator __p, value_type&& __v);
+    iterator insert_after(const_iterator __p, initializer_list<value_type> __il)
+        {return insert_after(__p, __il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+    iterator insert_after(const_iterator __p, const value_type& __v);
+    iterator insert_after(const_iterator __p, size_type __n, const value_type& __v);
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            __is_cpp17_input_iterator<_InputIterator>::value,
+            iterator
+        >::type
+        insert_after(const_iterator __p, _InputIterator __f, _InputIterator __l);
+
+    iterator erase_after(const_iterator __p);
+    iterator erase_after(const_iterator __f, const_iterator __l);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(forward_list& __x)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT
+#else
+        _NOEXCEPT_(!__node_traits::propagate_on_container_swap::value ||
+                   __is_nothrow_swappable<__node_allocator>::value)
+#endif
+        {base::swap(__x);}
+
+    void resize(size_type __n);
+    void resize(size_type __n, const value_type& __v);
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT {base::clear();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void splice_after(const_iterator __p, forward_list&& __x);
+    _LIBCPP_INLINE_VISIBILITY
+    void splice_after(const_iterator __p, forward_list&& __x, const_iterator __i);
+    _LIBCPP_INLINE_VISIBILITY
+    void splice_after(const_iterator __p, forward_list&& __x,
+                      const_iterator __f, const_iterator __l);
+    void splice_after(const_iterator __p, forward_list& __x);
+    void splice_after(const_iterator __p, forward_list& __x, const_iterator __i);
+    void splice_after(const_iterator __p, forward_list& __x,
+                      const_iterator __f, const_iterator __l);
+    __remove_return_type remove(const value_type& __v);
+    template <class _Predicate> __remove_return_type remove_if(_Predicate __pred);
+    _LIBCPP_INLINE_VISIBILITY
+    __remove_return_type unique() {return unique(__equal_to<value_type>());}
+    template <class _BinaryPredicate> __remove_return_type unique(_BinaryPredicate __binary_pred);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(forward_list&& __x) {merge(__x, __less<value_type>());}
+    template <class _Compare>
+        _LIBCPP_INLINE_VISIBILITY
+        void merge(forward_list&& __x, _Compare __comp)
+        {merge(__x, _VSTD::move(__comp));}
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(forward_list& __x) {merge(__x, __less<value_type>());}
+    template <class _Compare> void merge(forward_list& __x, _Compare __comp);
+    _LIBCPP_INLINE_VISIBILITY
+    void sort() {sort(__less<value_type>());}
+    template <class _Compare> _LIBCPP_INLINE_VISIBILITY void sort(_Compare __comp);
+    void reverse() _NOEXCEPT;
+
+private:
+
+#ifndef _LIBCPP_CXX03_LANG
+    void __move_assign(forward_list& __x, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value);
+    void __move_assign(forward_list& __x, false_type);
+#endif // _LIBCPP_CXX03_LANG
+
+    template <class _Compare>
+        static
+        __node_pointer
+        __merge(__node_pointer __f1, __node_pointer __f2, _Compare& __comp);
+
+    template <class _Compare>
+        static
+        __node_pointer
+        __sort(__node_pointer __f, difference_type __sz, _Compare& __comp);
+};
+
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator,
+         class _Alloc = allocator<__iter_value_type<_InputIterator>>,
+         class = enable_if_t<__is_allocator<_Alloc>::value>
+         >
+forward_list(_InputIterator, _InputIterator)
+  -> forward_list<__iter_value_type<_InputIterator>, _Alloc>;
+
+template<class _InputIterator,
+         class _Alloc,
+         class = enable_if_t<__is_allocator<_Alloc>::value>
+         >
+forward_list(_InputIterator, _InputIterator, _Alloc)
+  -> forward_list<__iter_value_type<_InputIterator>, _Alloc>;
+#endif
+
+template <class _Tp, class _Alloc>
+inline
+forward_list<_Tp, _Alloc>::forward_list(const allocator_type& __a)
+    : base(__a)
+{
+}
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(size_type __n)
+{
+    if (__n > 0)
+    {
+        __node_allocator& __a = base::__alloc();
+        typedef __allocator_destructor<__node_allocator> _Dp;
+        unique_ptr<__node, _Dp> __h(nullptr, _Dp(__a, 1));
+        for (__begin_node_pointer __p = base::__before_begin(); __n > 0; --__n,
+                                                             __p = __p->__next_as_begin())
+        {
+            __h.reset(__node_traits::allocate(__a, 1));
+            __node_traits::construct(__a, _VSTD::addressof(__h->__value_));
+            __h->__next_ = nullptr;
+            __p->__next_ = __h.release();
+        }
+    }
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(size_type __n,
+                                        const allocator_type& __base_alloc)
+    : base ( __base_alloc )
+{
+    if (__n > 0)
+    {
+        __node_allocator& __a = base::__alloc();
+        typedef __allocator_destructor<__node_allocator> _Dp;
+        unique_ptr<__node, _Dp> __h(nullptr, _Dp(__a, 1));
+        for (__begin_node_pointer __p = base::__before_begin(); __n > 0; --__n,
+                                                             __p = __p->__next_as_begin())
+        {
+            __h.reset(__node_traits::allocate(__a, 1));
+            __node_traits::construct(__a, _VSTD::addressof(__h->__value_));
+            __h->__next_ = nullptr;
+            __p->__next_ = __h.release();
+        }
+    }
+}
+#endif
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(size_type __n, const value_type& __v)
+{
+    insert_after(cbefore_begin(), __n, __v);
+}
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(size_type __n, const value_type& __v,
+                                        const allocator_type& __a)
+    : base(__a)
+{
+    insert_after(cbefore_begin(), __n, __v);
+}
+
+template <class _Tp, class _Alloc>
+template <class _InputIterator>
+forward_list<_Tp, _Alloc>::forward_list(_InputIterator __f, _InputIterator __l,
+                                        typename enable_if<
+                                          __is_cpp17_input_iterator<_InputIterator>::value
+                                        >::type*)
+{
+    insert_after(cbefore_begin(), __f, __l);
+}
+
+template <class _Tp, class _Alloc>
+template <class _InputIterator>
+forward_list<_Tp, _Alloc>::forward_list(_InputIterator __f, _InputIterator __l,
+                                        const allocator_type& __a,
+                                        typename enable_if<
+                                          __is_cpp17_input_iterator<_InputIterator>::value
+                                        >::type*)
+    : base(__a)
+{
+    insert_after(cbefore_begin(), __f, __l);
+}
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(const forward_list& __x)
+    : base(
+          __node_traits::select_on_container_copy_construction(__x.__alloc())) {
+  insert_after(cbefore_begin(), __x.begin(), __x.end());
+}
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(const forward_list& __x,
+                                        const __identity_t<allocator_type>& __a)
+    : base(__a)
+{
+    insert_after(cbefore_begin(), __x.begin(), __x.end());
+}
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>&
+forward_list<_Tp, _Alloc>::operator=(const forward_list& __x)
+{
+    if (this != _VSTD::addressof(__x))
+    {
+        base::__copy_assign_alloc(__x);
+        assign(__x.begin(), __x.end());
+    }
+    return *this;
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(forward_list&& __x,
+                                        const __identity_t<allocator_type>& __a)
+    : base(_VSTD::move(__x), __a)
+{
+    if (base::__alloc() != __x.__alloc())
+    {
+        typedef move_iterator<iterator> _Ip;
+        insert_after(cbefore_begin(), _Ip(__x.begin()), _Ip(__x.end()));
+    }
+}
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(initializer_list<value_type> __il)
+{
+    insert_after(cbefore_begin(), __il.begin(), __il.end());
+}
+
+template <class _Tp, class _Alloc>
+forward_list<_Tp, _Alloc>::forward_list(initializer_list<value_type> __il,
+                                        const allocator_type& __a)
+    : base(__a)
+{
+    insert_after(cbefore_begin(), __il.begin(), __il.end());
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::__move_assign(forward_list& __x, true_type)
+    _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
+{
+    clear();
+    base::__move_assign_alloc(__x);
+    base::__before_begin()->__next_ = __x.__before_begin()->__next_;
+    __x.__before_begin()->__next_ = nullptr;
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::__move_assign(forward_list& __x, false_type)
+{
+    if (base::__alloc() == __x.__alloc())
+        __move_assign(__x, true_type());
+    else
+    {
+        typedef move_iterator<iterator> _Ip;
+        assign(_Ip(__x.begin()), _Ip(__x.end()));
+    }
+}
+
+template <class _Tp, class _Alloc>
+inline
+forward_list<_Tp, _Alloc>&
+forward_list<_Tp, _Alloc>::operator=(forward_list&& __x)
+    _NOEXCEPT_(
+             __node_traits::propagate_on_container_move_assignment::value &&
+             is_nothrow_move_assignable<allocator_type>::value)
+{
+    __move_assign(__x, integral_constant<bool,
+          __node_traits::propagate_on_container_move_assignment::value>());
+    return *this;
+}
+
+template <class _Tp, class _Alloc>
+inline
+forward_list<_Tp, _Alloc>&
+forward_list<_Tp, _Alloc>::operator=(initializer_list<value_type> __il)
+{
+    assign(__il.begin(), __il.end());
+    return *this;
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+template <class _InputIterator>
+typename enable_if
+<
+    __is_cpp17_input_iterator<_InputIterator>::value,
+    void
+>::type
+forward_list<_Tp, _Alloc>::assign(_InputIterator __f, _InputIterator __l)
+{
+    iterator __i = before_begin();
+    iterator __j = _VSTD::next(__i);
+    iterator __e = end();
+    for (; __j != __e && __f != __l; ++__i, (void) ++__j, ++__f)
+        *__j = *__f;
+    if (__j == __e)
+        insert_after(__i, __f, __l);
+    else
+        erase_after(__i, __e);
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::assign(size_type __n, const value_type& __v)
+{
+    iterator __i = before_begin();
+    iterator __j = _VSTD::next(__i);
+    iterator __e = end();
+    for (; __j != __e && __n > 0; --__n, ++__i, ++__j)
+        *__j = __v;
+    if (__j == __e)
+        insert_after(__i, __n, __v);
+    else
+        erase_after(__i, __e);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+inline
+void
+forward_list<_Tp, _Alloc>::assign(initializer_list<value_type> __il)
+{
+    assign(__il.begin(), __il.end());
+}
+
+template <class _Tp, class _Alloc>
+template <class... _Args>
+#if _LIBCPP_STD_VER > 14
+typename forward_list<_Tp, _Alloc>::reference
+#else
+void
+#endif
+forward_list<_Tp, _Alloc>::emplace_front(_Args&&... __args)
+{
+    __node_allocator& __a = base::__alloc();
+    typedef __allocator_destructor<__node_allocator> _Dp;
+    unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+    __node_traits::construct(__a, _VSTD::addressof(__h->__value_),
+                                  _VSTD::forward<_Args>(__args)...);
+    __h->__next_ = base::__before_begin()->__next_;
+    base::__before_begin()->__next_ = __h.release();
+#if _LIBCPP_STD_VER > 14
+    return base::__before_begin()->__next_->__value_;
+#endif
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::push_front(value_type&& __v)
+{
+    __node_allocator& __a = base::__alloc();
+    typedef __allocator_destructor<__node_allocator> _Dp;
+    unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+    __node_traits::construct(__a, _VSTD::addressof(__h->__value_), _VSTD::move(__v));
+    __h->__next_ = base::__before_begin()->__next_;
+    base::__before_begin()->__next_ = __h.release();
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::push_front(const value_type& __v)
+{
+    __node_allocator& __a = base::__alloc();
+    typedef __allocator_destructor<__node_allocator> _Dp;
+    unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+    __node_traits::construct(__a, _VSTD::addressof(__h->__value_), __v);
+    __h->__next_ = base::__before_begin()->__next_;
+    base::__before_begin()->__next_ = __h.release();
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::pop_front()
+{
+    __node_allocator& __a = base::__alloc();
+    __node_pointer __p = base::__before_begin()->__next_;
+    base::__before_begin()->__next_ = __p->__next_;
+    __node_traits::destroy(__a, _VSTD::addressof(__p->__value_));
+    __node_traits::deallocate(__a, __p, 1);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+template <class... _Args>
+typename forward_list<_Tp, _Alloc>::iterator
+forward_list<_Tp, _Alloc>::emplace_after(const_iterator __p, _Args&&... __args)
+{
+    __begin_node_pointer const __r = __p.__get_begin();
+    __node_allocator& __a = base::__alloc();
+    typedef __allocator_destructor<__node_allocator> _Dp;
+    unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+    __node_traits::construct(__a, _VSTD::addressof(__h->__value_),
+                                  _VSTD::forward<_Args>(__args)...);
+    __h->__next_ = __r->__next_;
+    __r->__next_ = __h.release();
+    return iterator(__r->__next_);
+}
+
+template <class _Tp, class _Alloc>
+typename forward_list<_Tp, _Alloc>::iterator
+forward_list<_Tp, _Alloc>::insert_after(const_iterator __p, value_type&& __v)
+{
+    __begin_node_pointer const __r = __p.__get_begin();
+    __node_allocator& __a = base::__alloc();
+    typedef __allocator_destructor<__node_allocator> _Dp;
+    unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+    __node_traits::construct(__a, _VSTD::addressof(__h->__value_), _VSTD::move(__v));
+    __h->__next_ = __r->__next_;
+    __r->__next_ = __h.release();
+    return iterator(__r->__next_);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+typename forward_list<_Tp, _Alloc>::iterator
+forward_list<_Tp, _Alloc>::insert_after(const_iterator __p, const value_type& __v)
+{
+    __begin_node_pointer const __r = __p.__get_begin();
+    __node_allocator& __a = base::__alloc();
+    typedef __allocator_destructor<__node_allocator> _Dp;
+    unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+    __node_traits::construct(__a, _VSTD::addressof(__h->__value_), __v);
+    __h->__next_ = __r->__next_;
+    __r->__next_ = __h.release();
+    return iterator(__r->__next_);
+}
+
+template <class _Tp, class _Alloc>
+typename forward_list<_Tp, _Alloc>::iterator
+forward_list<_Tp, _Alloc>::insert_after(const_iterator __p, size_type __n,
+                                        const value_type& __v)
+{
+    __begin_node_pointer __r = __p.__get_begin();
+    if (__n > 0)
+    {
+        __node_allocator& __a = base::__alloc();
+        typedef __allocator_destructor<__node_allocator> _Dp;
+        unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+        __node_traits::construct(__a, _VSTD::addressof(__h->__value_), __v);
+        __node_pointer __first = __h.release();
+        __node_pointer __last = __first;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (--__n; __n != 0; --__n, __last = __last->__next_)
+            {
+                __h.reset(__node_traits::allocate(__a, 1));
+                __node_traits::construct(__a, _VSTD::addressof(__h->__value_), __v);
+                __last->__next_ = __h.release();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            while (__first != nullptr)
+            {
+                __node_pointer __next = __first->__next_;
+                __node_traits::destroy(__a, _VSTD::addressof(__first->__value_));
+                __node_traits::deallocate(__a, __first, 1);
+                __first = __next;
+            }
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __last->__next_ = __r->__next_;
+        __r->__next_ = __first;
+        __r = static_cast<__begin_node_pointer>(__last);
+    }
+    return iterator(__r);
+}
+
+template <class _Tp, class _Alloc>
+template <class _InputIterator>
+typename enable_if
+<
+    __is_cpp17_input_iterator<_InputIterator>::value,
+    typename forward_list<_Tp, _Alloc>::iterator
+>::type
+forward_list<_Tp, _Alloc>::insert_after(const_iterator __p,
+                                        _InputIterator __f, _InputIterator __l)
+{
+    __begin_node_pointer __r = __p.__get_begin();
+    if (__f != __l)
+    {
+        __node_allocator& __a = base::__alloc();
+        typedef __allocator_destructor<__node_allocator> _Dp;
+        unique_ptr<__node, _Dp> __h(__node_traits::allocate(__a, 1), _Dp(__a, 1));
+        __node_traits::construct(__a, _VSTD::addressof(__h->__value_), *__f);
+        __node_pointer __first = __h.release();
+        __node_pointer __last = __first;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (++__f; __f != __l; ++__f, ((void)(__last = __last->__next_)))
+            {
+                __h.reset(__node_traits::allocate(__a, 1));
+                __node_traits::construct(__a, _VSTD::addressof(__h->__value_), *__f);
+                __last->__next_ = __h.release();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            while (__first != nullptr)
+            {
+                __node_pointer __next = __first->__next_;
+                __node_traits::destroy(__a, _VSTD::addressof(__first->__value_));
+                __node_traits::deallocate(__a, __first, 1);
+                __first = __next;
+            }
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __last->__next_ = __r->__next_;
+        __r->__next_ = __first;
+        __r = static_cast<__begin_node_pointer>(__last);
+    }
+    return iterator(__r);
+}
+
+template <class _Tp, class _Alloc>
+typename forward_list<_Tp, _Alloc>::iterator
+forward_list<_Tp, _Alloc>::erase_after(const_iterator __f)
+{
+    __begin_node_pointer __p = __f.__get_begin();
+    __node_pointer __n = __p->__next_;
+    __p->__next_ = __n->__next_;
+    __node_allocator& __a = base::__alloc();
+    __node_traits::destroy(__a, _VSTD::addressof(__n->__value_));
+    __node_traits::deallocate(__a, __n, 1);
+    return iterator(__p->__next_);
+}
+
+template <class _Tp, class _Alloc>
+typename forward_list<_Tp, _Alloc>::iterator
+forward_list<_Tp, _Alloc>::erase_after(const_iterator __f, const_iterator __l)
+{
+    __node_pointer __e = __l.__get_unsafe_node_pointer();
+    if (__f != __l)
+    {
+        __begin_node_pointer __bp = __f.__get_begin();
+
+        __node_pointer __n = __bp->__next_;
+        if (__n != __e)
+        {
+            __bp->__next_ = __e;
+            __node_allocator& __a = base::__alloc();
+            do
+            {
+                __node_pointer __tmp = __n->__next_;
+                __node_traits::destroy(__a, _VSTD::addressof(__n->__value_));
+                __node_traits::deallocate(__a, __n, 1);
+                __n = __tmp;
+            } while (__n != __e);
+        }
+    }
+    return iterator(__e);
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::resize(size_type __n)
+{
+    size_type __sz = 0;
+    iterator __p = before_begin();
+    iterator __i = begin();
+    iterator __e = end();
+    for (; __i != __e && __sz < __n; ++__p, ++__i, ++__sz)
+        ;
+    if (__i != __e)
+        erase_after(__p, __e);
+    else
+    {
+        __n -= __sz;
+        if (__n > 0)
+        {
+            __node_allocator& __a = base::__alloc();
+            typedef __allocator_destructor<__node_allocator> _Dp;
+            unique_ptr<__node, _Dp> __h(nullptr, _Dp(__a, 1));
+            for (__begin_node_pointer __ptr = __p.__get_begin(); __n > 0; --__n,
+                                                         __ptr = __ptr->__next_as_begin())
+            {
+                __h.reset(__node_traits::allocate(__a, 1));
+                __node_traits::construct(__a, _VSTD::addressof(__h->__value_));
+                __h->__next_ = nullptr;
+                __ptr->__next_ = __h.release();
+            }
+        }
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::resize(size_type __n, const value_type& __v)
+{
+    size_type __sz = 0;
+    iterator __p = before_begin();
+    iterator __i = begin();
+    iterator __e = end();
+    for (; __i != __e && __sz < __n; ++__p, ++__i, ++__sz)
+        ;
+    if (__i != __e)
+        erase_after(__p, __e);
+    else
+    {
+        __n -= __sz;
+        if (__n > 0)
+        {
+            __node_allocator& __a = base::__alloc();
+            typedef __allocator_destructor<__node_allocator> _Dp;
+            unique_ptr<__node, _Dp> __h(nullptr, _Dp(__a, 1));
+            for (__begin_node_pointer __ptr = __p.__get_begin(); __n > 0; --__n,
+                                                         __ptr = __ptr->__next_as_begin())
+            {
+                __h.reset(__node_traits::allocate(__a, 1));
+                __node_traits::construct(__a, _VSTD::addressof(__h->__value_), __v);
+                __h->__next_ = nullptr;
+                __ptr->__next_ = __h.release();
+            }
+        }
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::splice_after(const_iterator __p,
+                                        forward_list& __x)
+{
+    if (!__x.empty())
+    {
+        if (__p.__get_begin()->__next_ != nullptr)
+        {
+            const_iterator __lm1 = __x.before_begin();
+            while (__lm1.__get_begin()->__next_ != nullptr)
+                ++__lm1;
+            __lm1.__get_begin()->__next_ = __p.__get_begin()->__next_;
+        }
+        __p.__get_begin()->__next_ = __x.__before_begin()->__next_;
+        __x.__before_begin()->__next_ = nullptr;
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::splice_after(const_iterator __p,
+                                        forward_list& /*__other*/,
+                                        const_iterator __i)
+{
+    const_iterator __lm1 = _VSTD::next(__i);
+    if (__p != __i && __p != __lm1)
+    {
+        __i.__get_begin()->__next_ = __lm1.__get_begin()->__next_;
+        __lm1.__get_begin()->__next_ = __p.__get_begin()->__next_;
+        __p.__get_begin()->__next_ = __lm1.__get_unsafe_node_pointer();
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::splice_after(const_iterator __p,
+                                        forward_list& /*__other*/,
+                                        const_iterator __f, const_iterator __l)
+{
+    if (__f != __l && __p != __f)
+    {
+        const_iterator __lm1 = __f;
+        while (__lm1.__get_begin()->__next_ != __l.__get_begin())
+            ++__lm1;
+        if (__f != __lm1)
+        {
+            __lm1.__get_begin()->__next_ = __p.__get_begin()->__next_;
+            __p.__get_begin()->__next_ = __f.__get_begin()->__next_;
+            __f.__get_begin()->__next_ = __l.__get_unsafe_node_pointer();
+        }
+    }
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+forward_list<_Tp, _Alloc>::splice_after(const_iterator __p,
+                                        forward_list&& __x)
+{
+    splice_after(__p, __x);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+forward_list<_Tp, _Alloc>::splice_after(const_iterator __p,
+                                        forward_list&& __x,
+                                        const_iterator __i)
+{
+    splice_after(__p, __x, __i);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+forward_list<_Tp, _Alloc>::splice_after(const_iterator __p,
+                                        forward_list&& __x,
+                                        const_iterator __f, const_iterator __l)
+{
+    splice_after(__p, __x, __f, __l);
+}
+
+template <class _Tp, class _Alloc>
+typename forward_list<_Tp, _Alloc>::__remove_return_type
+forward_list<_Tp, _Alloc>::remove(const value_type& __v)
+{
+    forward_list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
+    typename forward_list<_Tp, _Alloc>::size_type __count_removed = 0;
+    const iterator __e = end();
+    for (iterator __i = before_begin(); __i.__get_begin()->__next_ != nullptr;)
+    {
+        if (__i.__get_begin()->__next_->__value_ == __v)
+        {
+            ++__count_removed;
+            iterator __j = _VSTD::next(__i, 2);
+            for (; __j != __e && *__j == __v; ++__j)
+                ++__count_removed;
+            __deleted_nodes.splice_after(__deleted_nodes.before_begin(), *this, __i, __j);
+            if (__j == __e)
+                break;
+            __i = __j;
+        }
+        else
+            ++__i;
+    }
+
+    return (__remove_return_type) __count_removed;
+}
+
+template <class _Tp, class _Alloc>
+template <class _Predicate>
+typename forward_list<_Tp, _Alloc>::__remove_return_type
+forward_list<_Tp, _Alloc>::remove_if(_Predicate __pred)
+{
+    forward_list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
+    typename forward_list<_Tp, _Alloc>::size_type __count_removed = 0;
+    const iterator __e = end();
+    for (iterator __i = before_begin(); __i.__get_begin()->__next_ != nullptr;)
+    {
+        if (__pred(__i.__get_begin()->__next_->__value_))
+        {
+            ++__count_removed;
+            iterator __j = _VSTD::next(__i, 2);
+            for (; __j != __e && __pred(*__j); ++__j)
+                ++__count_removed;
+            __deleted_nodes.splice_after(__deleted_nodes.before_begin(), *this, __i, __j);
+            if (__j == __e)
+                break;
+            __i = __j;
+        }
+        else
+            ++__i;
+    }
+
+    return (__remove_return_type) __count_removed;
+}
+
+template <class _Tp, class _Alloc>
+template <class _BinaryPredicate>
+typename forward_list<_Tp, _Alloc>::__remove_return_type
+forward_list<_Tp, _Alloc>::unique(_BinaryPredicate __binary_pred)
+{
+    forward_list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
+    typename forward_list<_Tp, _Alloc>::size_type __count_removed = 0;
+    for (iterator __i = begin(), __e = end(); __i != __e;)
+    {
+        iterator __j = _VSTD::next(__i);
+        for (; __j != __e && __binary_pred(*__i, *__j); ++__j)
+            ++__count_removed;
+        if (__i.__get_begin()->__next_ != __j.__get_unsafe_node_pointer())
+            __deleted_nodes.splice_after(__deleted_nodes.before_begin(), *this, __i, __j);
+        __i = __j;
+    }
+
+    return (__remove_return_type) __count_removed;
+}
+
+template <class _Tp, class _Alloc>
+template <class _Compare>
+void
+forward_list<_Tp, _Alloc>::merge(forward_list& __x, _Compare __comp)
+{
+    if (this != &__x)
+    {
+        base::__before_begin()->__next_ = __merge(base::__before_begin()->__next_,
+                                                    __x.__before_begin()->__next_,
+                                                    __comp);
+        __x.__before_begin()->__next_ = nullptr;
+    }
+}
+
+template <class _Tp, class _Alloc>
+template <class _Compare>
+typename forward_list<_Tp, _Alloc>::__node_pointer
+forward_list<_Tp, _Alloc>::__merge(__node_pointer __f1, __node_pointer __f2,
+                                   _Compare& __comp)
+{
+    if (__f1 == nullptr)
+        return __f2;
+    if (__f2 == nullptr)
+        return __f1;
+    __node_pointer __r;
+    if (__comp(__f2->__value_, __f1->__value_))
+    {
+        __node_pointer __t = __f2;
+        while (__t->__next_ != nullptr &&
+                             __comp(__t->__next_->__value_, __f1->__value_))
+            __t = __t->__next_;
+        __r = __f2;
+        __f2 = __t->__next_;
+        __t->__next_ = __f1;
+    }
+    else
+        __r = __f1;
+    __node_pointer __p = __f1;
+    __f1 = __f1->__next_;
+    while (__f1 != nullptr && __f2 != nullptr)
+    {
+        if (__comp(__f2->__value_, __f1->__value_))
+        {
+            __node_pointer __t = __f2;
+            while (__t->__next_ != nullptr &&
+                                 __comp(__t->__next_->__value_, __f1->__value_))
+                __t = __t->__next_;
+            __p->__next_ = __f2;
+            __f2 = __t->__next_;
+            __t->__next_ = __f1;
+        }
+        __p = __f1;
+        __f1 = __f1->__next_;
+    }
+    if (__f2 != nullptr)
+        __p->__next_ = __f2;
+    return __r;
+}
+
+template <class _Tp, class _Alloc>
+template <class _Compare>
+inline
+void
+forward_list<_Tp, _Alloc>::sort(_Compare __comp)
+{
+    base::__before_begin()->__next_ = __sort(base::__before_begin()->__next_,
+                                       _VSTD::distance(begin(), end()), __comp);
+}
+
+template <class _Tp, class _Alloc>
+template <class _Compare>
+typename forward_list<_Tp, _Alloc>::__node_pointer
+forward_list<_Tp, _Alloc>::__sort(__node_pointer __f1, difference_type __sz,
+                                  _Compare& __comp)
+{
+    switch (__sz)
+    {
+    case 0:
+    case 1:
+        return __f1;
+    case 2:
+        if (__comp(__f1->__next_->__value_, __f1->__value_))
+        {
+            __node_pointer __t = __f1->__next_;
+            __t->__next_ = __f1;
+            __f1->__next_ = nullptr;
+            __f1 = __t;
+        }
+        return __f1;
+    }
+    difference_type __sz1 = __sz / 2;
+    difference_type __sz2 = __sz - __sz1;
+    __node_pointer __t = _VSTD::next(iterator(__f1), __sz1 - 1).__get_unsafe_node_pointer();
+    __node_pointer __f2 = __t->__next_;
+    __t->__next_ = nullptr;
+    return __merge(__sort(__f1, __sz1, __comp),
+                   __sort(__f2, __sz2, __comp), __comp);
+}
+
+template <class _Tp, class _Alloc>
+void
+forward_list<_Tp, _Alloc>::reverse() _NOEXCEPT
+{
+    __node_pointer __p = base::__before_begin()->__next_;
+    if (__p != nullptr)
+    {
+        __node_pointer __f = __p->__next_;
+        __p->__next_ = nullptr;
+        while (__f != nullptr)
+        {
+            __node_pointer __t = __f->__next_;
+            __f->__next_ = __p;
+            __p = __f;
+            __f = __t;
+        }
+        base::__before_begin()->__next_ = __p;
+    }
+}
+
+template <class _Tp, class _Alloc>
+bool operator==(const forward_list<_Tp, _Alloc>& __x,
+                const forward_list<_Tp, _Alloc>& __y)
+{
+    typedef forward_list<_Tp, _Alloc> _Cp;
+    typedef typename _Cp::const_iterator _Ip;
+    _Ip __ix = __x.begin();
+    _Ip __ex = __x.end();
+    _Ip __iy = __y.begin();
+    _Ip __ey = __y.end();
+    for (; __ix != __ex && __iy != __ey; ++__ix, ++__iy)
+        if (!(*__ix == *__iy))
+            return false;
+    return (__ix == __ex) == (__iy == __ey);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator!=(const forward_list<_Tp, _Alloc>& __x,
+                const forward_list<_Tp, _Alloc>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator< (const forward_list<_Tp, _Alloc>& __x,
+                const forward_list<_Tp, _Alloc>& __y)
+{
+    return _VSTD::lexicographical_compare(__x.begin(), __x.end(),
+                                         __y.begin(), __y.end());
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator> (const forward_list<_Tp, _Alloc>& __x,
+                const forward_list<_Tp, _Alloc>& __y)
+{
+    return __y < __x;
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator>=(const forward_list<_Tp, _Alloc>& __x,
+                const forward_list<_Tp, _Alloc>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator<=(const forward_list<_Tp, _Alloc>& __x,
+                const forward_list<_Tp, _Alloc>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(forward_list<_Tp, _Alloc>& __x, forward_list<_Tp, _Alloc>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Tp, class _Allocator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+    typename forward_list<_Tp, _Allocator>::size_type
+    erase_if(forward_list<_Tp, _Allocator>& __c, _Predicate __pred) {
+  return __c.remove_if(__pred);
+}
+
+template <class _Tp, class _Allocator, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+    typename forward_list<_Tp, _Allocator>::size_type
+    erase(forward_list<_Tp, _Allocator>& __c, const _Up& __v) {
+  return _VSTD::erase_if(__c, [&](auto& __elem) { return __elem == __v; });
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_FORWARD_LIST
diff --git a/contrib/libs/cxxsupp/libcxx/include/fstream b/contrib/libs/cxxsupp/libcxx/include/fstream
new file mode 100644
index 00000000000..d5a9aca37d4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/fstream
@@ -0,0 +1,1727 @@
+// -*- C++ -*-
+//===------------------------- fstream ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_FSTREAM
+#define _LIBCPP_FSTREAM
+
+/*
+    fstream synopsis
+
+template <class charT, class traits = char_traits<charT> >
+class basic_filebuf
+    : public basic_streambuf<charT, traits>
+{
+public:
+    typedef charT                          char_type;
+    typedef traits                         traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    // 27.9.1.2 Constructors/destructor:
+    basic_filebuf();
+    basic_filebuf(basic_filebuf&& rhs);
+    virtual ~basic_filebuf();
+
+    // 27.9.1.3 Assign/swap:
+    basic_filebuf& operator=(basic_filebuf&& rhs);
+    void swap(basic_filebuf& rhs);
+
+    // 27.9.1.4 Members:
+    bool is_open() const;
+    basic_filebuf* open(const char* s, ios_base::openmode mode);
+    basic_filebuf* open(const string& s, ios_base::openmode mode);
+    basic_filebuf* open(const filesystem::path& p, ios_base::openmode mode); // C++17
+    basic_filebuf* close();
+
+protected:
+    // 27.9.1.5 Overridden virtual functions:
+    virtual streamsize showmanyc();
+    virtual int_type underflow();
+    virtual int_type uflow();
+    virtual int_type pbackfail(int_type c = traits_type::eof());
+    virtual int_type overflow (int_type c = traits_type::eof());
+    virtual basic_streambuf<char_type, traits_type>* setbuf(char_type* s, streamsize n);
+    virtual pos_type seekoff(off_type off, ios_base::seekdir way,
+                             ios_base::openmode which = ios_base::in | ios_base::out);
+    virtual pos_type seekpos(pos_type sp,
+                             ios_base::openmode which = ios_base::in | ios_base::out);
+    virtual int sync();
+    virtual void imbue(const locale& loc);
+};
+
+template <class charT, class traits>
+  void
+  swap(basic_filebuf<charT, traits>& x, basic_filebuf<charT, traits>& y);
+
+typedef basic_filebuf<char>    filebuf;
+typedef basic_filebuf<wchar_t> wfilebuf;
+
+template <class charT, class traits = char_traits<charT> >
+class basic_ifstream
+    : public basic_istream<charT,traits>
+{
+public:
+    typedef charT                          char_type;
+    typedef traits                         traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    basic_ifstream();
+    explicit basic_ifstream(const char* s, ios_base::openmode mode = ios_base::in);
+    explicit basic_ifstream(const string& s, ios_base::openmode mode = ios_base::in);
+    explicit basic_ifstream(const filesystem::path& p,
+                            ios_base::openmode mode = ios_base::in); // C++17
+    basic_ifstream(basic_ifstream&& rhs);
+
+    basic_ifstream& operator=(basic_ifstream&& rhs);
+    void swap(basic_ifstream& rhs);
+
+    basic_filebuf<char_type, traits_type>* rdbuf() const;
+    bool is_open() const;
+    void open(const char* s, ios_base::openmode mode = ios_base::in);
+    void open(const string& s, ios_base::openmode mode = ios_base::in);
+    void open(const filesystem::path& s, ios_base::openmode mode = ios_base::in); // C++17
+
+    void close();
+};
+
+template <class charT, class traits>
+  void
+  swap(basic_ifstream<charT, traits>& x, basic_ifstream<charT, traits>& y);
+
+typedef basic_ifstream<char>    ifstream;
+typedef basic_ifstream<wchar_t> wifstream;
+
+template <class charT, class traits = char_traits<charT> >
+class basic_ofstream
+    : public basic_ostream<charT,traits>
+{
+public:
+    typedef charT                          char_type;
+    typedef traits                         traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    basic_ofstream();
+    explicit basic_ofstream(const char* s, ios_base::openmode mode = ios_base::out);
+    explicit basic_ofstream(const string& s, ios_base::openmode mode = ios_base::out);
+    explicit basic_ofstream(const filesystem::path& p,
+                            ios_base::openmode mode = ios_base::out); // C++17
+    basic_ofstream(basic_ofstream&& rhs);
+
+    basic_ofstream& operator=(basic_ofstream&& rhs);
+    void swap(basic_ofstream& rhs);
+
+    basic_filebuf<char_type, traits_type>* rdbuf() const;
+    bool is_open() const;
+    void open(const char* s, ios_base::openmode mode = ios_base::out);
+    void open(const string& s, ios_base::openmode mode = ios_base::out);
+    void open(const filesystem::path& p,
+              ios_base::openmode mode = ios_base::out); // C++17
+
+    void close();
+};
+
+template <class charT, class traits>
+  void
+  swap(basic_ofstream<charT, traits>& x, basic_ofstream<charT, traits>& y);
+
+typedef basic_ofstream<char>    ofstream;
+typedef basic_ofstream<wchar_t> wofstream;
+
+template <class charT, class traits=char_traits<charT> >
+class basic_fstream
+    : public basic_iostream<charT,traits>
+{
+public:
+    typedef charT                          char_type;
+    typedef traits                         traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    basic_fstream();
+    explicit basic_fstream(const char* s, ios_base::openmode mode = ios_base::in|ios_base::out);
+    explicit basic_fstream(const string& s, ios_base::openmode mode = ios_base::in|ios_base::out);
+    explicit basic_fstream(const filesystem::path& p,
+                           ios_base::openmode mode = ios_base::in|ios_base::out); C++17
+    basic_fstream(basic_fstream&& rhs);
+
+    basic_fstream& operator=(basic_fstream&& rhs);
+    void swap(basic_fstream& rhs);
+
+    basic_filebuf<char_type, traits_type>* rdbuf() const;
+    bool is_open() const;
+    void open(const char* s, ios_base::openmode mode = ios_base::in|ios_base::out);
+    void open(const string& s, ios_base::openmode mode = ios_base::in|ios_base::out);
+    void open(const filesystem::path& s,
+              ios_base::openmode mode = ios_base::in|ios_base::out); // C++17
+
+    void close();
+};
+
+template <class charT, class traits>
+  void swap(basic_fstream<charT, traits>& x, basic_fstream<charT, traits>& y);
+
+typedef basic_fstream<char>    fstream;
+typedef basic_fstream<wchar_t> wfstream;
+
+}  // std
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <__debug>
+#include <__locale>
+#include <cstdio>
+#include <cstdlib>
+#include <istream>
+#include <ostream>
+
+#if !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
+#include <filesystem>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#if defined(_LIBCPP_MSVCRT) || defined(_NEWLIB_VERSION)
+#  define _LIBCPP_HAS_NO_OFF_T_FUNCTIONS
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _CharT, class _Traits>
+class _LIBCPP_TEMPLATE_VIS basic_filebuf
+    : public basic_streambuf<_CharT, _Traits>
+{
+public:
+    typedef _CharT                           char_type;
+    typedef _Traits                          traits_type;
+    typedef typename traits_type::int_type   int_type;
+    typedef typename traits_type::pos_type   pos_type;
+    typedef typename traits_type::off_type   off_type;
+    typedef typename traits_type::state_type state_type;
+
+    // 27.9.1.2 Constructors/destructor:
+    basic_filebuf();
+    basic_filebuf(basic_filebuf&& __rhs);
+    virtual ~basic_filebuf();
+
+    // 27.9.1.3 Assign/swap:
+    _LIBCPP_INLINE_VISIBILITY
+    basic_filebuf& operator=(basic_filebuf&& __rhs);
+    void swap(basic_filebuf& __rhs);
+
+    // 27.9.1.4 Members:
+    _LIBCPP_INLINE_VISIBILITY
+    bool is_open() const;
+    basic_filebuf* open(const char* __s, ios_base::openmode __mode);
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+    basic_filebuf* open(const wchar_t* __s, ios_base::openmode __mode);
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    basic_filebuf* open(const string& __s, ios_base::openmode __mode);
+
+#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
+    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
+    basic_filebuf* open(const _VSTD_FS::path& __p, ios_base::openmode __mode) {
+      return open(__p.c_str(), __mode);
+    }
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    basic_filebuf* __open(int __fd, ios_base::openmode __mode);
+    basic_filebuf* close();
+
+    _LIBCPP_INLINE_VISIBILITY
+    inline static const char*
+    __make_mdstring(ios_base::openmode __mode) _NOEXCEPT;
+
+  protected:
+    // 27.9.1.5 Overridden virtual functions:
+    virtual int_type underflow();
+    virtual int_type pbackfail(int_type __c = traits_type::eof());
+    virtual int_type overflow (int_type __c = traits_type::eof());
+    virtual basic_streambuf<char_type, traits_type>* setbuf(char_type* __s, streamsize __n);
+    virtual pos_type seekoff(off_type __off, ios_base::seekdir __way,
+                             ios_base::openmode __wch = ios_base::in | ios_base::out);
+    virtual pos_type seekpos(pos_type __sp,
+                             ios_base::openmode __wch = ios_base::in | ios_base::out);
+    virtual int sync();
+    virtual void imbue(const locale& __loc);
+
+private:
+  char* __extbuf_;
+  const char* __extbufnext_;
+  const char* __extbufend_;
+  char __extbuf_min_[8];
+  size_t __ebs_;
+  char_type* __intbuf_;
+  size_t __ibs_;
+  FILE* __file_;
+  const codecvt<char_type, char, state_type>* __cv_;
+  state_type __st_;
+  state_type __st_last_;
+  ios_base::openmode __om_;
+  ios_base::openmode __cm_;
+  bool __owns_eb_;
+  bool __owns_ib_;
+  bool __always_noconv_;
+
+  bool __read_mode();
+  void __write_mode();
+};
+
+template <class _CharT, class _Traits>
+basic_filebuf<_CharT, _Traits>::basic_filebuf()
+    : __extbuf_(nullptr),
+      __extbufnext_(nullptr),
+      __extbufend_(nullptr),
+      __ebs_(0),
+      __intbuf_(nullptr),
+      __ibs_(0),
+      __file_(nullptr),
+      __cv_(nullptr),
+      __st_(),
+      __st_last_(),
+      __om_(0),
+      __cm_(0),
+      __owns_eb_(false),
+      __owns_ib_(false),
+      __always_noconv_(false)
+{
+    if (has_facet<codecvt<char_type, char, state_type> >(this->getloc()))
+    {
+        __cv_ = &use_facet<codecvt<char_type, char, state_type> >(this->getloc());
+        __always_noconv_ = __cv_->always_noconv();
+    }
+    setbuf(nullptr, 4096);
+}
+
+template <class _CharT, class _Traits>
+basic_filebuf<_CharT, _Traits>::basic_filebuf(basic_filebuf&& __rhs)
+    : basic_streambuf<_CharT, _Traits>(__rhs)
+{
+    if (__rhs.__extbuf_ == __rhs.__extbuf_min_)
+    {
+        __extbuf_ = __extbuf_min_;
+        __extbufnext_ = __extbuf_ + (__rhs.__extbufnext_ - __rhs.__extbuf_);
+        __extbufend_ = __extbuf_ + (__rhs.__extbufend_ - __rhs.__extbuf_);
+    }
+    else
+    {
+        __extbuf_ = __rhs.__extbuf_;
+        __extbufnext_ = __rhs.__extbufnext_;
+        __extbufend_ = __rhs.__extbufend_;
+    }
+    __ebs_ = __rhs.__ebs_;
+    __intbuf_ = __rhs.__intbuf_;
+    __ibs_ = __rhs.__ibs_;
+    __file_ = __rhs.__file_;
+    __cv_ = __rhs.__cv_;
+    __st_ = __rhs.__st_;
+    __st_last_ = __rhs.__st_last_;
+    __om_ = __rhs.__om_;
+    __cm_ = __rhs.__cm_;
+    __owns_eb_ = __rhs.__owns_eb_;
+    __owns_ib_ = __rhs.__owns_ib_;
+    __always_noconv_ = __rhs.__always_noconv_;
+    if (__rhs.pbase())
+    {
+        if (__rhs.pbase() == __rhs.__intbuf_)
+            this->setp(__intbuf_, __intbuf_ + (__rhs. epptr() - __rhs.pbase()));
+        else
+            this->setp((char_type*)__extbuf_,
+                       (char_type*)__extbuf_ + (__rhs. epptr() - __rhs.pbase()));
+        this->__pbump(__rhs. pptr() - __rhs.pbase());
+    }
+    else if (__rhs.eback())
+    {
+        if (__rhs.eback() == __rhs.__intbuf_)
+            this->setg(__intbuf_, __intbuf_ + (__rhs.gptr() - __rhs.eback()),
+                                  __intbuf_ + (__rhs.egptr() - __rhs.eback()));
+        else
+            this->setg((char_type*)__extbuf_,
+                       (char_type*)__extbuf_ + (__rhs.gptr() - __rhs.eback()),
+                       (char_type*)__extbuf_ + (__rhs.egptr() - __rhs.eback()));
+    }
+    __rhs.__extbuf_ = nullptr;
+    __rhs.__extbufnext_ = nullptr;
+    __rhs.__extbufend_ = nullptr;
+    __rhs.__ebs_ = 0;
+    __rhs.__intbuf_ = 0;
+    __rhs.__ibs_ = 0;
+    __rhs.__file_ = nullptr;
+    __rhs.__st_ = state_type();
+    __rhs.__st_last_ = state_type();
+    __rhs.__om_ = 0;
+    __rhs.__cm_ = 0;
+    __rhs.__owns_eb_ = false;
+    __rhs.__owns_ib_ = false;
+    __rhs.setg(0, 0, 0);
+    __rhs.setp(0, 0);
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_filebuf<_CharT, _Traits>&
+basic_filebuf<_CharT, _Traits>::operator=(basic_filebuf&& __rhs)
+{
+    close();
+    swap(__rhs);
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_filebuf<_CharT, _Traits>::~basic_filebuf()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        close();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    if (__owns_eb_)
+        delete [] __extbuf_;
+    if (__owns_ib_)
+        delete [] __intbuf_;
+}
+
+template <class _CharT, class _Traits>
+void
+basic_filebuf<_CharT, _Traits>::swap(basic_filebuf& __rhs)
+{
+    basic_streambuf<char_type, traits_type>::swap(__rhs);
+    if (__extbuf_ != __extbuf_min_ && __rhs.__extbuf_ != __rhs.__extbuf_min_)
+    {
+        _VSTD::swap(__extbuf_, __rhs.__extbuf_);
+        _VSTD::swap(__extbufnext_, __rhs.__extbufnext_);
+        _VSTD::swap(__extbufend_, __rhs.__extbufend_);
+    }
+    else
+    {
+        ptrdiff_t __ln = __extbufnext_ - __extbuf_;
+        ptrdiff_t __le = __extbufend_ - __extbuf_;
+        ptrdiff_t __rn = __rhs.__extbufnext_ - __rhs.__extbuf_;
+        ptrdiff_t __re = __rhs.__extbufend_ - __rhs.__extbuf_;
+        if (__extbuf_ == __extbuf_min_ && __rhs.__extbuf_ != __rhs.__extbuf_min_)
+        {
+            __extbuf_ = __rhs.__extbuf_;
+            __rhs.__extbuf_ = __rhs.__extbuf_min_;
+        }
+        else if (__extbuf_ != __extbuf_min_ && __rhs.__extbuf_ == __rhs.__extbuf_min_)
+        {
+            __rhs.__extbuf_ = __extbuf_;
+            __extbuf_ = __extbuf_min_;
+        }
+        __extbufnext_ = __extbuf_ + __rn;
+        __extbufend_ = __extbuf_ + __re;
+        __rhs.__extbufnext_ = __rhs.__extbuf_ + __ln;
+        __rhs.__extbufend_ = __rhs.__extbuf_ + __le;
+    }
+    _VSTD::swap(__ebs_, __rhs.__ebs_);
+    _VSTD::swap(__intbuf_, __rhs.__intbuf_);
+    _VSTD::swap(__ibs_, __rhs.__ibs_);
+    _VSTD::swap(__file_, __rhs.__file_);
+    _VSTD::swap(__cv_, __rhs.__cv_);
+    _VSTD::swap(__st_, __rhs.__st_);
+    _VSTD::swap(__st_last_, __rhs.__st_last_);
+    _VSTD::swap(__om_, __rhs.__om_);
+    _VSTD::swap(__cm_, __rhs.__cm_);
+    _VSTD::swap(__owns_eb_, __rhs.__owns_eb_);
+    _VSTD::swap(__owns_ib_, __rhs.__owns_ib_);
+    _VSTD::swap(__always_noconv_, __rhs.__always_noconv_);
+    if (this->eback() == (char_type*)__rhs.__extbuf_min_)
+    {
+        ptrdiff_t __n = this->gptr() - this->eback();
+        ptrdiff_t __e = this->egptr() - this->eback();
+        this->setg((char_type*)__extbuf_min_,
+                   (char_type*)__extbuf_min_ + __n,
+                   (char_type*)__extbuf_min_ + __e);
+    }
+    else if (this->pbase() == (char_type*)__rhs.__extbuf_min_)
+    {
+        ptrdiff_t __n = this->pptr() - this->pbase();
+        ptrdiff_t __e = this->epptr() - this->pbase();
+        this->setp((char_type*)__extbuf_min_,
+                   (char_type*)__extbuf_min_ + __e);
+        this->__pbump(__n);
+    }
+    if (__rhs.eback() == (char_type*)__extbuf_min_)
+    {
+        ptrdiff_t __n = __rhs.gptr() - __rhs.eback();
+        ptrdiff_t __e = __rhs.egptr() - __rhs.eback();
+        __rhs.setg((char_type*)__rhs.__extbuf_min_,
+                   (char_type*)__rhs.__extbuf_min_ + __n,
+                   (char_type*)__rhs.__extbuf_min_ + __e);
+    }
+    else if (__rhs.pbase() == (char_type*)__extbuf_min_)
+    {
+        ptrdiff_t __n = __rhs.pptr() - __rhs.pbase();
+        ptrdiff_t __e = __rhs.epptr() - __rhs.pbase();
+        __rhs.setp((char_type*)__rhs.__extbuf_min_,
+                   (char_type*)__rhs.__extbuf_min_ + __e);
+        __rhs.__pbump(__n);
+    }
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(basic_filebuf<_CharT, _Traits>& __x, basic_filebuf<_CharT, _Traits>& __y)
+{
+    __x.swap(__y);
+}
+
+template <class _CharT, class _Traits>
+inline
+bool
+basic_filebuf<_CharT, _Traits>::is_open() const
+{
+    return __file_ != nullptr;
+}
+
+template <class _CharT, class _Traits>
+const char* basic_filebuf<_CharT, _Traits>::__make_mdstring(
+    ios_base::openmode __mode) _NOEXCEPT {
+  switch (__mode & ~ios_base::ate) {
+  case ios_base::out:
+  case ios_base::out | ios_base::trunc:
+    return "w" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::out | ios_base::app:
+  case ios_base::app:
+    return "a" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::in:
+    return "r" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::in | ios_base::out:
+    return "r+" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::in | ios_base::out | ios_base::trunc:
+    return "w+" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::in | ios_base::out | ios_base::app:
+  case ios_base::in | ios_base::app:
+    return "a+" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::out | ios_base::binary:
+  case ios_base::out | ios_base::trunc | ios_base::binary:
+    return "wb" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::out | ios_base::app | ios_base::binary:
+  case ios_base::app | ios_base::binary:
+    return "ab" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::in | ios_base::binary:
+    return "rb" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::in | ios_base::out | ios_base::binary:
+    return "r+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary:
+    return "w+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:
+  case ios_base::in | ios_base::app | ios_base::binary:
+    return "a+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  default:
+    return nullptr;
+  }
+  _LIBCPP_UNREACHABLE();
+}
+
+template <class _CharT, class _Traits>
+basic_filebuf<_CharT, _Traits>*
+basic_filebuf<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode)
+{
+    basic_filebuf<_CharT, _Traits>* __rt = nullptr;
+    if (__file_ == nullptr)
+    {
+      if (const char* __mdstr = __make_mdstring(__mode)) {
+        __rt = this;
+        __file_ = fopen(__s, __mdstr);
+        if (__file_) {
+          __om_ = __mode;
+          if (__mode & ios_base::ate) {
+            if (fseek(__file_, 0, SEEK_END)) {
+              fclose(__file_);
+              __file_ = nullptr;
+              __rt = nullptr;
+            }
+          }
+        } else
+          __rt = nullptr;
+      }
+    }
+    return __rt;
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_filebuf<_CharT, _Traits>*
+basic_filebuf<_CharT, _Traits>::__open(int __fd, ios_base::openmode __mode) {
+  basic_filebuf<_CharT, _Traits>* __rt = nullptr;
+  if (__file_ == nullptr) {
+    if (const char* __mdstr = __make_mdstring(__mode)) {
+      __rt = this;
+      __file_ = fdopen(__fd, __mdstr);
+      if (__file_) {
+        __om_ = __mode;
+        if (__mode & ios_base::ate) {
+          if (fseek(__file_, 0, SEEK_END)) {
+            fclose(__file_);
+            __file_ = nullptr;
+            __rt = nullptr;
+          }
+        }
+      } else
+        __rt = nullptr;
+    }
+  }
+  return __rt;
+}
+
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+// This is basically the same as the char* overload except that it uses _wfopen
+// and long mode strings.
+template <class _CharT, class _Traits>
+basic_filebuf<_CharT, _Traits>*
+basic_filebuf<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
+{
+    basic_filebuf<_CharT, _Traits>* __rt = nullptr;
+    if (__file_ == nullptr)
+    {
+        __rt = this;
+        const wchar_t* __mdstr;
+        switch (__mode & ~ios_base::ate)
+        {
+        case ios_base::out:
+        case ios_base::out | ios_base::trunc:
+            __mdstr = L"w";
+            break;
+        case ios_base::out | ios_base::app:
+        case ios_base::app:
+            __mdstr = L"a";
+            break;
+        case ios_base::in:
+            __mdstr = L"r";
+            break;
+        case ios_base::in | ios_base::out:
+            __mdstr = L"r+";
+            break;
+        case ios_base::in | ios_base::out | ios_base::trunc:
+            __mdstr = L"w+";
+            break;
+        case ios_base::in | ios_base::out | ios_base::app:
+        case ios_base::in | ios_base::app:
+            __mdstr = L"a+";
+            break;
+        case ios_base::out | ios_base::binary:
+        case ios_base::out | ios_base::trunc | ios_base::binary:
+            __mdstr = L"wb";
+            break;
+        case ios_base::out | ios_base::app | ios_base::binary:
+        case ios_base::app | ios_base::binary:
+            __mdstr = L"ab";
+            break;
+        case ios_base::in | ios_base::binary:
+            __mdstr = L"rb";
+            break;
+        case ios_base::in | ios_base::out | ios_base::binary:
+            __mdstr = L"r+b";
+            break;
+        case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary:
+            __mdstr = L"w+b";
+            break;
+        case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:
+        case ios_base::in | ios_base::app | ios_base::binary:
+            __mdstr = L"a+b";
+            break;
+        default:
+            __rt = nullptr;
+            break;
+        }
+        if (__rt)
+        {
+            __file_ = _wfopen(__s, __mdstr);
+            if (__file_)
+            {
+                __om_ = __mode;
+                if (__mode & ios_base::ate)
+                {
+                    if (fseek(__file_, 0, SEEK_END))
+                    {
+                        fclose(__file_);
+                        __file_ = nullptr;
+                        __rt = nullptr;
+                    }
+                }
+            }
+            else
+                __rt = nullptr;
+        }
+    }
+    return __rt;
+}
+#endif
+
+template <class _CharT, class _Traits>
+inline
+basic_filebuf<_CharT, _Traits>*
+basic_filebuf<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode)
+{
+    return open(__s.c_str(), __mode);
+}
+
+template <class _CharT, class _Traits>
+basic_filebuf<_CharT, _Traits>*
+basic_filebuf<_CharT, _Traits>::close()
+{
+    basic_filebuf<_CharT, _Traits>* __rt = nullptr;
+    if (__file_)
+    {
+        __rt = this;
+        unique_ptr<FILE, int(*)(FILE*)> __h(__file_, fclose);
+        if (sync())
+            __rt = nullptr;
+        if (fclose(__h.release()))
+            __rt = nullptr;
+        __file_ = nullptr;
+        setbuf(0, 0);
+    }
+    return __rt;
+}
+
+template <class _CharT, class _Traits>
+typename basic_filebuf<_CharT, _Traits>::int_type
+basic_filebuf<_CharT, _Traits>::underflow()
+{
+    if (__file_ == nullptr)
+        return traits_type::eof();
+    bool __initial = __read_mode();
+    char_type __1buf;
+    if (this->gptr() == nullptr)
+        this->setg(&__1buf, &__1buf+1, &__1buf+1);
+    const size_t __unget_sz = __initial ? 0 : min<size_t>((this->egptr() - this->eback()) / 2, 4);
+    int_type __c = traits_type::eof();
+    if (this->gptr() == this->egptr())
+    {
+        _VSTD::memmove(this->eback(), this->egptr() - __unget_sz, __unget_sz * sizeof(char_type));
+        if (__always_noconv_)
+        {
+            size_t __nmemb = static_cast<size_t>(this->egptr() - this->eback() - __unget_sz);
+            __nmemb = fread(this->eback() + __unget_sz, 1, __nmemb, __file_);
+            if (__nmemb != 0)
+            {
+                this->setg(this->eback(),
+                           this->eback() + __unget_sz,
+                           this->eback() + __unget_sz + __nmemb);
+                __c = traits_type::to_int_type(*this->gptr());
+            }
+        }
+        else
+        {
+            _LIBCPP_ASSERT ( !(__extbufnext_ == NULL && (__extbufend_ != __extbufnext_)), "underflow moving from NULL" );
+            if (__extbufend_ != __extbufnext_)
+                _VSTD::memmove(__extbuf_, __extbufnext_, __extbufend_ - __extbufnext_);
+            __extbufnext_ = __extbuf_ + (__extbufend_ - __extbufnext_);
+            __extbufend_ = __extbuf_ + (__extbuf_ == __extbuf_min_ ? sizeof(__extbuf_min_) : __ebs_);
+            size_t __nmemb = _VSTD::min(static_cast<size_t>(__ibs_ - __unget_sz),
+                                 static_cast<size_t>(__extbufend_ - __extbufnext_));
+            codecvt_base::result __r;
+            __st_last_ = __st_;
+            size_t __nr = fread((void*) const_cast<char *>(__extbufnext_), 1, __nmemb, __file_);
+            if (__nr != 0)
+            {
+                if (!__cv_)
+                    __throw_bad_cast();
+
+                __extbufend_ = __extbufnext_ + __nr;
+                char_type*  __inext;
+                __r = __cv_->in(__st_, __extbuf_, __extbufend_, __extbufnext_,
+                                       this->eback() + __unget_sz,
+                                       this->eback() + __ibs_, __inext);
+                if (__r == codecvt_base::noconv)
+                {
+                    this->setg((char_type*)__extbuf_, (char_type*)__extbuf_,
+                                          (char_type*)const_cast<char *>(__extbufend_));
+                    __c = traits_type::to_int_type(*this->gptr());
+                }
+                else if (__inext != this->eback() + __unget_sz)
+                {
+                    this->setg(this->eback(), this->eback() + __unget_sz, __inext);
+                    __c = traits_type::to_int_type(*this->gptr());
+                }
+            }
+        }
+    }
+    else
+        __c = traits_type::to_int_type(*this->gptr());
+    if (this->eback() == &__1buf)
+        this->setg(nullptr, nullptr, nullptr);
+    return __c;
+}
+
+template <class _CharT, class _Traits>
+typename basic_filebuf<_CharT, _Traits>::int_type
+basic_filebuf<_CharT, _Traits>::pbackfail(int_type __c)
+{
+    if (__file_ && this->eback() < this->gptr())
+    {
+        if (traits_type::eq_int_type(__c, traits_type::eof()))
+        {
+            this->gbump(-1);
+            return traits_type::not_eof(__c);
+        }
+        if ((__om_ & ios_base::out) ||
+            traits_type::eq(traits_type::to_char_type(__c), this->gptr()[-1]))
+        {
+            this->gbump(-1);
+            *this->gptr() = traits_type::to_char_type(__c);
+            return __c;
+        }
+    }
+    return traits_type::eof();
+}
+
+template <class _CharT, class _Traits>
+typename basic_filebuf<_CharT, _Traits>::int_type
+basic_filebuf<_CharT, _Traits>::overflow(int_type __c)
+{
+    if (__file_ == nullptr)
+        return traits_type::eof();
+    __write_mode();
+    char_type __1buf;
+    char_type* __pb_save = this->pbase();
+    char_type* __epb_save = this->epptr();
+    if (!traits_type::eq_int_type(__c, traits_type::eof()))
+    {
+        if (this->pptr() == nullptr)
+            this->setp(&__1buf, &__1buf+1);
+        *this->pptr() = traits_type::to_char_type(__c);
+        this->pbump(1);
+    }
+    if (this->pptr() != this->pbase())
+    {
+        if (__always_noconv_)
+        {
+            size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());
+            if (fwrite(this->pbase(), sizeof(char_type), __nmemb, __file_) != __nmemb)
+                return traits_type::eof();
+        }
+        else
+        {
+            char* __extbe = __extbuf_;
+            codecvt_base::result __r;
+            do
+            {
+                if (!__cv_)
+                    __throw_bad_cast();
+
+                const char_type* __e;
+                __r = __cv_->out(__st_, this->pbase(), this->pptr(), __e,
+                                        __extbuf_, __extbuf_ + __ebs_, __extbe);
+                if (__e == this->pbase())
+                    return traits_type::eof();
+                if (__r == codecvt_base::noconv)
+                {
+                    size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());
+                    if (fwrite(this->pbase(), 1, __nmemb, __file_) != __nmemb)
+                        return traits_type::eof();
+                }
+                else if (__r == codecvt_base::ok || __r == codecvt_base::partial)
+                {
+                    size_t __nmemb = static_cast<size_t>(__extbe - __extbuf_);
+                    if (fwrite(__extbuf_, 1, __nmemb, __file_) != __nmemb)
+                        return traits_type::eof();
+                    if (__r == codecvt_base::partial)
+                    {
+                        this->setp(const_cast<char_type*>(__e), this->pptr());
+                        this->__pbump(this->epptr() - this->pbase());
+                    }
+                }
+                else
+                    return traits_type::eof();
+            } while (__r == codecvt_base::partial);
+        }
+        this->setp(__pb_save, __epb_save);
+    }
+    return traits_type::not_eof(__c);
+}
+
+template <class _CharT, class _Traits>
+basic_streambuf<_CharT, _Traits>*
+basic_filebuf<_CharT, _Traits>::setbuf(char_type* __s, streamsize __n)
+{
+    this->setg(nullptr, nullptr, nullptr);
+    this->setp(nullptr, nullptr);
+    if (__owns_eb_)
+        delete [] __extbuf_;
+    if (__owns_ib_)
+        delete [] __intbuf_;
+    __ebs_ = __n;
+    if (__ebs_ > sizeof(__extbuf_min_))
+    {
+        if (__always_noconv_ && __s)
+        {
+            __extbuf_ = (char*)__s;
+            __owns_eb_ = false;
+        }
+        else
+        {
+            __extbuf_ = new char[__ebs_];
+            __owns_eb_ = true;
+        }
+    }
+    else
+    {
+        __extbuf_ = __extbuf_min_;
+        __ebs_ = sizeof(__extbuf_min_);
+        __owns_eb_ = false;
+    }
+    if (!__always_noconv_)
+    {
+        __ibs_ = max<streamsize>(__n, sizeof(__extbuf_min_));
+        if (__s && __ibs_ >= sizeof(__extbuf_min_))
+        {
+            __intbuf_ = __s;
+            __owns_ib_ = false;
+        }
+        else
+        {
+            __intbuf_ = new char_type[__ibs_];
+            __owns_ib_ = true;
+        }
+    }
+    else
+    {
+        __ibs_ = 0;
+        __intbuf_ = nullptr;
+        __owns_ib_ = false;
+    }
+    return this;
+}
+
+template <class _CharT, class _Traits>
+typename basic_filebuf<_CharT, _Traits>::pos_type
+basic_filebuf<_CharT, _Traits>::seekoff(off_type __off, ios_base::seekdir __way,
+                                        ios_base::openmode)
+{
+    if (!__cv_)
+        __throw_bad_cast();
+
+    int __width = __cv_->encoding();
+    if (__file_ == nullptr || (__width <= 0 && __off != 0) || sync())
+        return pos_type(off_type(-1));
+    // __width > 0 || __off == 0
+    int __whence;
+    switch (__way)
+    {
+    case ios_base::beg:
+        __whence = SEEK_SET;
+        break;
+    case ios_base::cur:
+        __whence = SEEK_CUR;
+        break;
+    case ios_base::end:
+        __whence = SEEK_END;
+        break;
+    default:
+        return pos_type(off_type(-1));
+    }
+#if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
+    if (fseek(__file_, __width > 0 ? __width * __off : 0, __whence))
+        return pos_type(off_type(-1));
+    pos_type __r = ftell(__file_);
+#else
+    if (fseeko(__file_, __width > 0 ? __width * __off : 0, __whence))
+        return pos_type(off_type(-1));
+    pos_type __r = ftello(__file_);
+#endif
+    __r.state(__st_);
+    return __r;
+}
+
+template <class _CharT, class _Traits>
+typename basic_filebuf<_CharT, _Traits>::pos_type
+basic_filebuf<_CharT, _Traits>::seekpos(pos_type __sp, ios_base::openmode)
+{
+    if (__file_ == nullptr || sync())
+        return pos_type(off_type(-1));
+#if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
+    if (fseek(__file_, __sp, SEEK_SET))
+        return pos_type(off_type(-1));
+#else
+    if (fseeko(__file_, __sp, SEEK_SET))
+        return pos_type(off_type(-1));
+#endif
+    __st_ = __sp.state();
+    return __sp;
+}
+
+template <class _CharT, class _Traits>
+int
+basic_filebuf<_CharT, _Traits>::sync()
+{
+    if (__file_ == nullptr)
+        return 0;
+    if (!__cv_)
+        __throw_bad_cast();
+
+    if (__cm_ & ios_base::out)
+    {
+        if (this->pptr() != this->pbase())
+            if (overflow() == traits_type::eof())
+                return -1;
+        codecvt_base::result __r;
+        do
+        {
+            char* __extbe;
+            __r = __cv_->unshift(__st_, __extbuf_, __extbuf_ + __ebs_, __extbe);
+            size_t __nmemb = static_cast<size_t>(__extbe - __extbuf_);
+            if (fwrite(__extbuf_, 1, __nmemb, __file_) != __nmemb)
+                return -1;
+        } while (__r == codecvt_base::partial);
+        if (__r == codecvt_base::error)
+            return -1;
+        if (fflush(__file_))
+            return -1;
+    }
+    else if (__cm_ & ios_base::in)
+    {
+        off_type __c;
+        state_type __state = __st_last_;
+        bool __update_st = false;
+        if (__always_noconv_)
+            __c = this->egptr() - this->gptr();
+        else
+        {
+            int __width = __cv_->encoding();
+            __c = __extbufend_ - __extbufnext_;
+            if (__width > 0)
+                __c += __width * (this->egptr() - this->gptr());
+            else
+            {
+                if (this->gptr() != this->egptr())
+                {
+                    const int __off =  __cv_->length(__state, __extbuf_,
+                                                     __extbufnext_,
+                                                     this->gptr() - this->eback());
+                    __c += __extbufnext_ - __extbuf_ - __off;
+                    __update_st = true;
+                }
+            }
+        }
+#if defined(_LIBCPP_HAS_NO_OFF_T_FUNCTIONS)
+        if (fseek(__file_, -__c, SEEK_CUR))
+            return -1;
+#else
+        if (fseeko(__file_, -__c, SEEK_CUR))
+            return -1;
+#endif
+        if (__update_st)
+            __st_ = __state;
+        __extbufnext_ = __extbufend_ = __extbuf_;
+        this->setg(nullptr, nullptr, nullptr);
+        __cm_ = 0;
+    }
+    return 0;
+}
+
+template <class _CharT, class _Traits>
+void
+basic_filebuf<_CharT, _Traits>::imbue(const locale& __loc)
+{
+    sync();
+    __cv_ = &use_facet<codecvt<char_type, char, state_type> >(__loc);
+    bool __old_anc = __always_noconv_;
+    __always_noconv_ = __cv_->always_noconv();
+    if (__old_anc != __always_noconv_)
+    {
+        this->setg(nullptr, nullptr, nullptr);
+        this->setp(nullptr, nullptr);
+        // invariant, char_type is char, else we couldn't get here
+        if (__always_noconv_)  // need to dump __intbuf_
+        {
+            if (__owns_eb_)
+                delete [] __extbuf_;
+            __owns_eb_ = __owns_ib_;
+            __ebs_ = __ibs_;
+            __extbuf_ = (char*)__intbuf_;
+            __ibs_ = 0;
+            __intbuf_ = nullptr;
+            __owns_ib_ = false;
+        }
+        else  // need to obtain an __intbuf_.
+        {     // If __extbuf_ is user-supplied, use it, else new __intbuf_
+            if (!__owns_eb_ && __extbuf_ != __extbuf_min_)
+            {
+                __ibs_ = __ebs_;
+                __intbuf_ = (char_type*)__extbuf_;
+                __owns_ib_ = false;
+                __extbuf_ = new char[__ebs_];
+                __owns_eb_ = true;
+            }
+            else
+            {
+                __ibs_ = __ebs_;
+                __intbuf_ = new char_type[__ibs_];
+                __owns_ib_ = true;
+            }
+        }
+    }
+}
+
+template <class _CharT, class _Traits>
+bool
+basic_filebuf<_CharT, _Traits>::__read_mode()
+{
+    if (!(__cm_ & ios_base::in))
+    {
+        this->setp(nullptr, nullptr);
+        if (__always_noconv_)
+            this->setg((char_type*)__extbuf_,
+                       (char_type*)__extbuf_ + __ebs_,
+                       (char_type*)__extbuf_ + __ebs_);
+        else
+            this->setg(__intbuf_, __intbuf_ + __ibs_, __intbuf_ + __ibs_);
+        __cm_ = ios_base::in;
+        return true;
+    }
+    return false;
+}
+
+template <class _CharT, class _Traits>
+void
+basic_filebuf<_CharT, _Traits>::__write_mode()
+{
+    if (!(__cm_ & ios_base::out))
+    {
+        this->setg(nullptr, nullptr, nullptr);
+        if (__ebs_ > sizeof(__extbuf_min_))
+        {
+            if (__always_noconv_)
+                this->setp((char_type*)__extbuf_,
+                           (char_type*)__extbuf_ + (__ebs_ - 1));
+            else
+                this->setp(__intbuf_, __intbuf_ + (__ibs_ - 1));
+        }
+        else
+            this->setp(nullptr, nullptr);
+        __cm_ = ios_base::out;
+    }
+}
+
+// basic_ifstream
+
+template <class _CharT, class _Traits>
+class _LIBCPP_TEMPLATE_VIS basic_ifstream
+    : public basic_istream<_CharT, _Traits>
+{
+public:
+    typedef _CharT                         char_type;
+    typedef _Traits                        traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ifstream();
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in);
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_ifstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::in);
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_ifstream(const string& __s, ios_base::openmode __mode = ios_base::in);
+#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
+    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
+    explicit basic_ifstream(const filesystem::path& __p, ios_base::openmode __mode = ios_base::in)
+      : basic_ifstream(__p.c_str(), __mode) {}
+#endif // _LIBCPP_STD_VER >= 17
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ifstream(basic_ifstream&& __rhs);
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ifstream& operator=(basic_ifstream&& __rhs);
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(basic_ifstream& __rhs);
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_filebuf<char_type, traits_type>* rdbuf() const;
+    _LIBCPP_INLINE_VISIBILITY
+    bool is_open() const;
+    void open(const char* __s, ios_base::openmode __mode = ios_base::in);
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in);
+#endif
+    void open(const string& __s, ios_base::openmode __mode = ios_base::in);
+#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
+    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
+    void open(const filesystem::path& __p,
+              ios_base::openmode __mode = ios_base::in) {
+      return open(__p.c_str(), __mode);
+    }
+#endif // _LIBCPP_STD_VER >= 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __open(int __fd, ios_base::openmode __mode);
+    _LIBCPP_INLINE_VISIBILITY
+    void close();
+
+private:
+    basic_filebuf<char_type, traits_type> __sb_;
+};
+
+template <class _CharT, class _Traits>
+inline
+basic_ifstream<_CharT, _Traits>::basic_ifstream()
+    : basic_istream<char_type, traits_type>(&__sb_)
+{
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_ifstream<_CharT, _Traits>::basic_ifstream(const char* __s, ios_base::openmode __mode)
+    : basic_istream<char_type, traits_type>(&__sb_)
+{
+    if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
+        this->setstate(ios_base::failbit);
+}
+
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+template <class _CharT, class _Traits>
+inline
+basic_ifstream<_CharT, _Traits>::basic_ifstream(const wchar_t* __s, ios_base::openmode __mode)
+    : basic_istream<char_type, traits_type>(&__sb_)
+{
+    if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
+        this->setstate(ios_base::failbit);
+}
+#endif
+
+template <class _CharT, class _Traits>
+inline
+basic_ifstream<_CharT, _Traits>::basic_ifstream(const string& __s, ios_base::openmode __mode)
+    : basic_istream<char_type, traits_type>(&__sb_)
+{
+    if (__sb_.open(__s, __mode | ios_base::in) == nullptr)
+        this->setstate(ios_base::failbit);
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_ifstream<_CharT, _Traits>::basic_ifstream(basic_ifstream&& __rhs)
+    : basic_istream<char_type, traits_type>(_VSTD::move(__rhs)),
+      __sb_(_VSTD::move(__rhs.__sb_))
+{
+    this->set_rdbuf(&__sb_);
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_ifstream<_CharT, _Traits>&
+basic_ifstream<_CharT, _Traits>::operator=(basic_ifstream&& __rhs)
+{
+    basic_istream<char_type, traits_type>::operator=(_VSTD::move(__rhs));
+    __sb_ = _VSTD::move(__rhs.__sb_);
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+inline
+void
+basic_ifstream<_CharT, _Traits>::swap(basic_ifstream& __rhs)
+{
+    basic_istream<char_type, traits_type>::swap(__rhs);
+    __sb_.swap(__rhs.__sb_);
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(basic_ifstream<_CharT, _Traits>& __x, basic_ifstream<_CharT, _Traits>& __y)
+{
+    __x.swap(__y);
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_filebuf<_CharT, _Traits>*
+basic_ifstream<_CharT, _Traits>::rdbuf() const
+{
+    return const_cast<basic_filebuf<char_type, traits_type>*>(&__sb_);
+}
+
+template <class _CharT, class _Traits>
+inline
+bool
+basic_ifstream<_CharT, _Traits>::is_open() const
+{
+    return __sb_.is_open();
+}
+
+template <class _CharT, class _Traits>
+void
+basic_ifstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode)
+{
+    if (__sb_.open(__s, __mode | ios_base::in))
+        this->clear();
+    else
+        this->setstate(ios_base::failbit);
+}
+
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+template <class _CharT, class _Traits>
+void
+basic_ifstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
+{
+    if (__sb_.open(__s, __mode | ios_base::in))
+        this->clear();
+    else
+        this->setstate(ios_base::failbit);
+}
+#endif
+
+template <class _CharT, class _Traits>
+void
+basic_ifstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode)
+{
+    if (__sb_.open(__s, __mode | ios_base::in))
+        this->clear();
+    else
+        this->setstate(ios_base::failbit);
+}
+
+template <class _CharT, class _Traits>
+inline
+void basic_ifstream<_CharT, _Traits>::__open(int __fd,
+                                             ios_base::openmode __mode) {
+  if (__sb_.__open(__fd, __mode | ios_base::in))
+    this->clear();
+  else
+    this->setstate(ios_base::failbit);
+}
+
+template <class _CharT, class _Traits>
+inline
+void
+basic_ifstream<_CharT, _Traits>::close()
+{
+    if (__sb_.close() == 0)
+        this->setstate(ios_base::failbit);
+}
+
+// basic_ofstream
+
+template <class _CharT, class _Traits>
+class _LIBCPP_TEMPLATE_VIS basic_ofstream
+    : public basic_ostream<_CharT, _Traits>
+{
+public:
+    typedef _CharT                         char_type;
+    typedef _Traits                        traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ofstream();
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_ofstream(const char* __s, ios_base::openmode __mode = ios_base::out);
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_ofstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::out);
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_ofstream(const string& __s, ios_base::openmode __mode = ios_base::out);
+
+#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
+    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
+    explicit basic_ofstream(const filesystem::path& __p, ios_base::openmode __mode = ios_base::out)
+      : basic_ofstream(__p.c_str(), __mode) {}
+#endif // _LIBCPP_STD_VER >= 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ofstream(basic_ofstream&& __rhs);
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ofstream& operator=(basic_ofstream&& __rhs);
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(basic_ofstream& __rhs);
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_filebuf<char_type, traits_type>* rdbuf() const;
+    _LIBCPP_INLINE_VISIBILITY
+    bool is_open() const;
+    void open(const char* __s, ios_base::openmode __mode = ios_base::out);
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::out);
+#endif
+    void open(const string& __s, ios_base::openmode __mode = ios_base::out);
+
+#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
+    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
+    void open(const filesystem::path& __p, ios_base::openmode __mode = ios_base::out)
+    { return open(__p.c_str(), __mode); }
+#endif // _LIBCPP_STD_VER >= 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __open(int __fd, ios_base::openmode __mode);
+    _LIBCPP_INLINE_VISIBILITY
+    void close();
+
+private:
+    basic_filebuf<char_type, traits_type> __sb_;
+};
+
+template <class _CharT, class _Traits>
+inline
+basic_ofstream<_CharT, _Traits>::basic_ofstream()
+    : basic_ostream<char_type, traits_type>(&__sb_)
+{
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_ofstream<_CharT, _Traits>::basic_ofstream(const char* __s, ios_base::openmode __mode)
+    : basic_ostream<char_type, traits_type>(&__sb_)
+{
+    if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
+        this->setstate(ios_base::failbit);
+}
+
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+template <class _CharT, class _Traits>
+inline
+basic_ofstream<_CharT, _Traits>::basic_ofstream(const wchar_t* __s, ios_base::openmode __mode)
+    : basic_ostream<char_type, traits_type>(&__sb_)
+{
+    if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
+        this->setstate(ios_base::failbit);
+}
+#endif
+
+template <class _CharT, class _Traits>
+inline
+basic_ofstream<_CharT, _Traits>::basic_ofstream(const string& __s, ios_base::openmode __mode)
+    : basic_ostream<char_type, traits_type>(&__sb_)
+{
+    if (__sb_.open(__s, __mode | ios_base::out) == nullptr)
+        this->setstate(ios_base::failbit);
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_ofstream<_CharT, _Traits>::basic_ofstream(basic_ofstream&& __rhs)
+    : basic_ostream<char_type, traits_type>(_VSTD::move(__rhs)),
+      __sb_(_VSTD::move(__rhs.__sb_))
+{
+    this->set_rdbuf(&__sb_);
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_ofstream<_CharT, _Traits>&
+basic_ofstream<_CharT, _Traits>::operator=(basic_ofstream&& __rhs)
+{
+    basic_ostream<char_type, traits_type>::operator=(_VSTD::move(__rhs));
+    __sb_ = _VSTD::move(__rhs.__sb_);
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+inline
+void
+basic_ofstream<_CharT, _Traits>::swap(basic_ofstream& __rhs)
+{
+    basic_ostream<char_type, traits_type>::swap(__rhs);
+    __sb_.swap(__rhs.__sb_);
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(basic_ofstream<_CharT, _Traits>& __x, basic_ofstream<_CharT, _Traits>& __y)
+{
+    __x.swap(__y);
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_filebuf<_CharT, _Traits>*
+basic_ofstream<_CharT, _Traits>::rdbuf() const
+{
+    return const_cast<basic_filebuf<char_type, traits_type>*>(&__sb_);
+}
+
+template <class _CharT, class _Traits>
+inline
+bool
+basic_ofstream<_CharT, _Traits>::is_open() const
+{
+    return __sb_.is_open();
+}
+
+template <class _CharT, class _Traits>
+void
+basic_ofstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode)
+{
+    if (__sb_.open(__s, __mode | ios_base::out))
+        this->clear();
+    else
+        this->setstate(ios_base::failbit);
+}
+
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+template <class _CharT, class _Traits>
+void
+basic_ofstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
+{
+    if (__sb_.open(__s, __mode | ios_base::out))
+        this->clear();
+    else
+        this->setstate(ios_base::failbit);
+}
+#endif
+
+template <class _CharT, class _Traits>
+void
+basic_ofstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode)
+{
+    if (__sb_.open(__s, __mode | ios_base::out))
+        this->clear();
+    else
+        this->setstate(ios_base::failbit);
+}
+
+template <class _CharT, class _Traits>
+inline
+void basic_ofstream<_CharT, _Traits>::__open(int __fd,
+                                             ios_base::openmode __mode) {
+  if (__sb_.__open(__fd, __mode | ios_base::out))
+    this->clear();
+  else
+    this->setstate(ios_base::failbit);
+}
+
+template <class _CharT, class _Traits>
+inline
+void
+basic_ofstream<_CharT, _Traits>::close()
+{
+    if (__sb_.close() == nullptr)
+        this->setstate(ios_base::failbit);
+}
+
+// basic_fstream
+
+template <class _CharT, class _Traits>
+class _LIBCPP_TEMPLATE_VIS basic_fstream
+    : public basic_iostream<_CharT, _Traits>
+{
+public:
+    typedef _CharT                         char_type;
+    typedef _Traits                        traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_fstream();
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_fstream(const char* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_fstream(const wchar_t* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_fstream(const string& __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
+
+#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
+    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
+    explicit basic_fstream(const filesystem::path& __p, ios_base::openmode __mode = ios_base::in | ios_base::out)
+      : basic_fstream(__p.c_str(), __mode) {}
+#endif // _LIBCPP_STD_VER >= 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_fstream(basic_fstream&& __rhs);
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_fstream& operator=(basic_fstream&& __rhs);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(basic_fstream& __rhs);
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_filebuf<char_type, traits_type>* rdbuf() const;
+    _LIBCPP_INLINE_VISIBILITY
+    bool is_open() const;
+    void open(const char* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+    void open(const wchar_t* __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
+#endif
+    void open(const string& __s, ios_base::openmode __mode = ios_base::in | ios_base::out);
+
+#if _LIBCPP_STD_VER >= 17 && !defined(_LIBCPP_HAS_NO_FILESYSTEM_LIBRARY)
+    _LIBCPP_AVAILABILITY_FILESYSTEM _LIBCPP_INLINE_VISIBILITY
+    void open(const filesystem::path& __p, ios_base::openmode __mode = ios_base::in|ios_base::out)
+    { return open(__p.c_str(), __mode); }
+#endif // _LIBCPP_STD_VER >= 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    void close();
+
+private:
+    basic_filebuf<char_type, traits_type> __sb_;
+};
+
+template <class _CharT, class _Traits>
+inline
+basic_fstream<_CharT, _Traits>::basic_fstream()
+    : basic_iostream<char_type, traits_type>(&__sb_)
+{
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_fstream<_CharT, _Traits>::basic_fstream(const char* __s, ios_base::openmode __mode)
+    : basic_iostream<char_type, traits_type>(&__sb_)
+{
+    if (__sb_.open(__s, __mode) == nullptr)
+        this->setstate(ios_base::failbit);
+}
+
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+template <class _CharT, class _Traits>
+inline
+basic_fstream<_CharT, _Traits>::basic_fstream(const wchar_t* __s, ios_base::openmode __mode)
+    : basic_iostream<char_type, traits_type>(&__sb_)
+{
+    if (__sb_.open(__s, __mode) == nullptr)
+        this->setstate(ios_base::failbit);
+}
+#endif
+
+template <class _CharT, class _Traits>
+inline
+basic_fstream<_CharT, _Traits>::basic_fstream(const string& __s, ios_base::openmode __mode)
+    : basic_iostream<char_type, traits_type>(&__sb_)
+{
+    if (__sb_.open(__s, __mode) == nullptr)
+        this->setstate(ios_base::failbit);
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_fstream<_CharT, _Traits>::basic_fstream(basic_fstream&& __rhs)
+    : basic_iostream<char_type, traits_type>(_VSTD::move(__rhs)),
+      __sb_(_VSTD::move(__rhs.__sb_))
+{
+    this->set_rdbuf(&__sb_);
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_fstream<_CharT, _Traits>&
+basic_fstream<_CharT, _Traits>::operator=(basic_fstream&& __rhs)
+{
+    basic_iostream<char_type, traits_type>::operator=(_VSTD::move(__rhs));
+    __sb_ = _VSTD::move(__rhs.__sb_);
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+inline
+void
+basic_fstream<_CharT, _Traits>::swap(basic_fstream& __rhs)
+{
+    basic_iostream<char_type, traits_type>::swap(__rhs);
+    __sb_.swap(__rhs.__sb_);
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(basic_fstream<_CharT, _Traits>& __x, basic_fstream<_CharT, _Traits>& __y)
+{
+    __x.swap(__y);
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_filebuf<_CharT, _Traits>*
+basic_fstream<_CharT, _Traits>::rdbuf() const
+{
+    return const_cast<basic_filebuf<char_type, traits_type>*>(&__sb_);
+}
+
+template <class _CharT, class _Traits>
+inline
+bool
+basic_fstream<_CharT, _Traits>::is_open() const
+{
+    return __sb_.is_open();
+}
+
+template <class _CharT, class _Traits>
+void
+basic_fstream<_CharT, _Traits>::open(const char* __s, ios_base::openmode __mode)
+{
+    if (__sb_.open(__s, __mode))
+        this->clear();
+    else
+        this->setstate(ios_base::failbit);
+}
+
+#ifdef _LIBCPP_HAS_OPEN_WITH_WCHAR
+template <class _CharT, class _Traits>
+void
+basic_fstream<_CharT, _Traits>::open(const wchar_t* __s, ios_base::openmode __mode)
+{
+    if (__sb_.open(__s, __mode))
+        this->clear();
+    else
+        this->setstate(ios_base::failbit);
+}
+#endif
+
+template <class _CharT, class _Traits>
+void
+basic_fstream<_CharT, _Traits>::open(const string& __s, ios_base::openmode __mode)
+{
+    if (__sb_.open(__s, __mode))
+        this->clear();
+    else
+        this->setstate(ios_base::failbit);
+}
+
+template <class _CharT, class _Traits>
+inline
+void
+basic_fstream<_CharT, _Traits>::close()
+{
+    if (__sb_.close() == nullptr)
+        this->setstate(ios_base::failbit);
+}
+
+#if defined(_LIBCPP_ABI_ENABLE_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ifstream<char>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ofstream<char>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_filebuf<char>)
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_FSTREAM
diff --git a/contrib/libs/cxxsupp/libcxx/include/functional b/contrib/libs/cxxsupp/libcxx/include/functional
new file mode 100644
index 00000000000..53a5f2bc377
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/functional
@@ -0,0 +1,535 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_FUNCTIONAL
+#define _LIBCPP_FUNCTIONAL
+
+/*
+    functional synopsis
+
+namespace std
+{
+
+template <class Arg, class Result>
+struct unary_function
+{
+    typedef Arg    argument_type;
+    typedef Result result_type;
+};
+
+template <class Arg1, class Arg2, class Result>
+struct binary_function
+{
+    typedef Arg1   first_argument_type;
+    typedef Arg2   second_argument_type;
+    typedef Result result_type;
+};
+
+template <class T>
+class reference_wrapper
+    : public unary_function<T1, R> // if wrapping a unary functor
+    : public binary_function<T1, T2, R> // if wraping a binary functor
+{
+public:
+    // types
+    typedef T type;
+    typedef see below result_type; // Not always defined
+
+    // construct/copy/destroy
+    template<class U>
+      reference_wrapper(U&&);
+    reference_wrapper(const reference_wrapper<T>& x) noexcept;
+
+    // assignment
+    reference_wrapper& operator=(const reference_wrapper<T>& x) noexcept;
+
+    // access
+    operator T& () const noexcept;
+    T& get() const noexcept;
+
+    // invoke
+    template <class... ArgTypes>
+      typename result_of<T&(ArgTypes&&...)>::type
+          operator() (ArgTypes&&...) const;
+};
+
+template <class T>
+  reference_wrapper(T&) -> reference_wrapper<T>;
+
+template <class T> reference_wrapper<T> ref(T& t) noexcept;
+template <class T> void ref(const T&& t) = delete;
+template <class T> reference_wrapper<T> ref(reference_wrapper<T>t) noexcept;
+
+template <class T> reference_wrapper<const T> cref(const T& t) noexcept;
+template <class T> void cref(const T&& t) = delete;
+template <class T> reference_wrapper<const T> cref(reference_wrapper<T> t) noexcept;
+
+template <class T> struct unwrap_reference;                                       // since C++20
+template <class T> struct unwrap_ref_decay : unwrap_reference<decay_t<T>> { };    // since C++20
+template <class T> using unwrap_reference_t = typename unwrap_reference<T>::type; // since C++20
+template <class T> using unwrap_ref_decay_t = typename unwrap_ref_decay<T>::type; // since C++20
+
+template <class T> // <class T=void> in C++14
+struct plus {
+    T operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct minus {
+    T operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct multiplies {
+    T operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct divides {
+    T operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct modulus {
+    T operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct negate {
+    T operator()(const T& x) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct equal_to {
+    bool operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct not_equal_to {
+    bool operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct greater {
+    bool operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct less {
+    bool operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct greater_equal {
+    bool operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct less_equal {
+    bool operator()(const T& x, const T& y) const;
+};
+
+// [comparisons.three.way], class compare_three_way
+struct compare_three_way;
+
+template <class T> // <class T=void> in C++14
+struct logical_and {
+    bool operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct logical_or {
+    bool operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct logical_not {
+    bool operator()(const T& x) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct bit_and {
+    T operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct bit_or {
+    T operator()(const T& x, const T& y) const;
+};
+
+template <class T> // <class T=void> in C++14
+struct bit_xor {
+    T operator()(const T& x, const T& y) const;
+};
+
+template <class T=void> // C++14
+struct bit_not {
+    T operator()(const T& x) const;
+};
+
+struct identity; // C++20
+
+template <class Predicate>
+class unary_negate // deprecated in C++17, removed in C++20
+    : public unary_function<typename Predicate::argument_type, bool>
+{
+public:
+    explicit unary_negate(const Predicate& pred);
+    bool operator()(const typename Predicate::argument_type& x) const;
+};
+
+template <class Predicate> // deprecated in C++17, removed in C++20
+unary_negate<Predicate> not1(const Predicate& pred);
+
+template <class Predicate>
+class binary_negate // deprecated in C++17, removed in C++20
+    : public binary_function<typename Predicate::first_argument_type,
+                             typename Predicate::second_argument_type,
+                             bool>
+{
+public:
+    explicit binary_negate(const Predicate& pred);
+    bool operator()(const typename Predicate::first_argument_type& x,
+                    const typename Predicate::second_argument_type& y) const;
+};
+
+template <class Predicate> // deprecated in C++17, removed in C++20
+binary_negate<Predicate> not2(const Predicate& pred);
+
+template <class F>
+constexpr unspecified not_fn(F&& f); // C++17, constexpr in C++20
+
+template<class T> struct is_bind_expression;
+template<class T> struct is_placeholder;
+
+    // See C++14 20.9.9, Function object binders
+template <class T> inline constexpr bool is_bind_expression_v
+  = is_bind_expression<T>::value; // C++17
+template <class T> inline constexpr int is_placeholder_v
+  = is_placeholder<T>::value; // C++17
+
+
+template<class Fn, class... BoundArgs>
+  constexpr unspecified bind(Fn&&, BoundArgs&&...);  // constexpr in C++20
+template<class R, class Fn, class... BoundArgs>
+  constexpr unspecified bind(Fn&&, BoundArgs&&...);  // constexpr in C++20
+
+template<class F, class... Args>
+ constexpr // constexpr in C++20
+ invoke_result_t<F, Args...> invoke(F&& f, Args&&... args) // C++17
+    noexcept(is_nothrow_invocable_v<F, Args...>);
+
+namespace placeholders {
+  // M is the implementation-defined number of placeholders
+  extern unspecified _1;
+  extern unspecified _2;
+  .
+  .
+  .
+  extern unspecified _Mp;
+}
+
+template <class Operation>
+class binder1st     // deprecated in C++11, removed in C++17
+    : public unary_function<typename Operation::second_argument_type,
+                            typename Operation::result_type>
+{
+protected:
+    Operation                               op;
+    typename Operation::first_argument_type value;
+public:
+    binder1st(const Operation& x, const typename Operation::first_argument_type y);
+    typename Operation::result_type operator()(      typename Operation::second_argument_type& x) const;
+    typename Operation::result_type operator()(const typename Operation::second_argument_type& x) const;
+};
+
+template <class Operation, class T>
+binder1st<Operation> bind1st(const Operation& op, const T& x);  // deprecated in C++11, removed in C++17
+
+template <class Operation>
+class binder2nd     // deprecated in C++11, removed in C++17
+    : public unary_function<typename Operation::first_argument_type,
+                            typename Operation::result_type>
+{
+protected:
+    Operation                                op;
+    typename Operation::second_argument_type value;
+public:
+    binder2nd(const Operation& x, const typename Operation::second_argument_type y);
+    typename Operation::result_type operator()(      typename Operation::first_argument_type& x) const;
+    typename Operation::result_type operator()(const typename Operation::first_argument_type& x) const;
+};
+
+template <class Operation, class T>
+binder2nd<Operation> bind2nd(const Operation& op, const T& x);  // deprecated in C++11, removed in C++17
+
+template <class Arg, class Result>      // deprecated in C++11, removed in C++17
+class pointer_to_unary_function : public unary_function<Arg, Result>
+{
+public:
+    explicit pointer_to_unary_function(Result (*f)(Arg));
+    Result operator()(Arg x) const;
+};
+
+template <class Arg, class Result>
+pointer_to_unary_function<Arg,Result> ptr_fun(Result (*f)(Arg));      // deprecated in C++11, removed in C++17
+
+template <class Arg1, class Arg2, class Result>      // deprecated in C++11, removed in C++17
+class pointer_to_binary_function : public binary_function<Arg1, Arg2, Result>
+{
+public:
+    explicit pointer_to_binary_function(Result (*f)(Arg1, Arg2));
+    Result operator()(Arg1 x, Arg2 y) const;
+};
+
+template <class Arg1, class Arg2, class Result>
+pointer_to_binary_function<Arg1,Arg2,Result> ptr_fun(Result (*f)(Arg1,Arg2));      // deprecated in C++11, removed in C++17
+
+template<class S, class T>      // deprecated in C++11, removed in C++17
+class mem_fun_t : public unary_function<T*, S>
+{
+public:
+    explicit mem_fun_t(S (T::*p)());
+    S operator()(T* p) const;
+};
+
+template<class S, class T, class A>
+class mem_fun1_t : public binary_function<T*, A, S>      // deprecated in C++11, removed in C++17
+{
+public:
+    explicit mem_fun1_t(S (T::*p)(A));
+    S operator()(T* p, A x) const;
+};
+
+template<class S, class T>          mem_fun_t<S,T>    mem_fun(S (T::*f)());      // deprecated in C++11, removed in C++17
+template<class S, class T, class A> mem_fun1_t<S,T,A> mem_fun(S (T::*f)(A));     // deprecated in C++11, removed in C++17
+
+template<class S, class T>
+class mem_fun_ref_t : public unary_function<T, S>      // deprecated in C++11, removed in C++17
+{
+public:
+    explicit mem_fun_ref_t(S (T::*p)());
+    S operator()(T& p) const;
+};
+
+template<class S, class T, class A>
+class mem_fun1_ref_t : public binary_function<T, A, S>      // deprecated in C++11, removed in C++17
+{
+public:
+    explicit mem_fun1_ref_t(S (T::*p)(A));
+    S operator()(T& p, A x) const;
+};
+
+template<class S, class T>          mem_fun_ref_t<S,T>    mem_fun_ref(S (T::*f)());      // deprecated in C++11, removed in C++17
+template<class S, class T, class A> mem_fun1_ref_t<S,T,A> mem_fun_ref(S (T::*f)(A));     // deprecated in C++11, removed in C++17
+
+template <class S, class T>
+class const_mem_fun_t : public unary_function<const T*, S>      // deprecated in C++11, removed in C++17
+{
+public:
+    explicit const_mem_fun_t(S (T::*p)() const);
+    S operator()(const T* p) const;
+};
+
+template <class S, class T, class A>
+class const_mem_fun1_t : public binary_function<const T*, A, S>      // deprecated in C++11, removed in C++17
+{
+public:
+    explicit const_mem_fun1_t(S (T::*p)(A) const);
+    S operator()(const T* p, A x) const;
+};
+
+template <class S, class T>          const_mem_fun_t<S,T>    mem_fun(S (T::*f)() const);      // deprecated in C++11, removed in C++17
+template <class S, class T, class A> const_mem_fun1_t<S,T,A> mem_fun(S (T::*f)(A) const);     // deprecated in C++11, removed in C++17
+
+template <class S, class T>
+class const_mem_fun_ref_t : public unary_function<T, S>      // deprecated in C++11, removed in C++17
+{
+public:
+    explicit const_mem_fun_ref_t(S (T::*p)() const);
+    S operator()(const T& p) const;
+};
+
+template <class S, class T, class A>
+class const_mem_fun1_ref_t : public binary_function<T, A, S>      // deprecated in C++11, removed in C++17
+{
+public:
+    explicit const_mem_fun1_ref_t(S (T::*p)(A) const);
+    S operator()(const T& p, A x) const;
+};
+
+template <class S, class T>          const_mem_fun_ref_t<S,T>    mem_fun_ref(S (T::*f)() const);   // deprecated in C++11, removed in C++17
+template <class S, class T, class A> const_mem_fun1_ref_t<S,T,A> mem_fun_ref(S (T::*f)(A) const);  // deprecated in C++11, removed in C++17
+
+template<class R, class T>
+constexpr unspecified mem_fn(R T::*); // constexpr in C++20
+
+class bad_function_call
+    : public exception
+{
+};
+
+template<class> class function; // undefined
+
+template<class R, class... ArgTypes>
+class function<R(ArgTypes...)>
+  : public unary_function<T1, R>      // iff sizeof...(ArgTypes) == 1 and
+                                      // ArgTypes contains T1
+  : public binary_function<T1, T2, R> // iff sizeof...(ArgTypes) == 2 and
+                                      // ArgTypes contains T1 and T2
+{
+public:
+    typedef R result_type;
+
+    // construct/copy/destroy:
+    function() noexcept;
+    function(nullptr_t) noexcept;
+    function(const function&);
+    function(function&&) noexcept;
+    template<class F>
+      function(F);
+    template<Allocator Alloc>
+      function(allocator_arg_t, const Alloc&) noexcept;            // removed in C++17
+    template<Allocator Alloc>
+      function(allocator_arg_t, const Alloc&, nullptr_t) noexcept; // removed in C++17
+    template<Allocator Alloc>
+      function(allocator_arg_t, const Alloc&, const function&);    // removed in C++17
+    template<Allocator Alloc>
+      function(allocator_arg_t, const Alloc&, function&&);         // removed in C++17
+    template<class F, Allocator Alloc>
+      function(allocator_arg_t, const Alloc&, F);                  // removed in C++17
+
+    function& operator=(const function&);
+    function& operator=(function&&) noexcept;
+    function& operator=(nullptr_t) noexcept;
+    template<class F>
+      function& operator=(F&&);
+    template<class F>
+      function& operator=(reference_wrapper<F>) noexcept;
+
+    ~function();
+
+    // function modifiers:
+    void swap(function&) noexcept;
+    template<class F, class Alloc>
+      void assign(F&&, const Alloc&);                 // Removed in C++17
+
+    // function capacity:
+    explicit operator bool() const noexcept;
+
+    // function invocation:
+    R operator()(ArgTypes...) const;
+
+    // function target access:
+    const std::type_info& target_type() const noexcept;
+    template <typename T>       T* target() noexcept;
+    template <typename T> const T* target() const noexcept;
+};
+
+// Deduction guides
+template<class R, class ...Args>
+function(R(*)(Args...)) -> function<R(Args...)>; // since C++17
+
+template<class F>
+function(F) -> function<see-below>; // since C++17
+
+// Null pointer comparisons:
+template <class R, class ... ArgTypes>
+  bool operator==(const function<R(ArgTypes...)>&, nullptr_t) noexcept;
+
+template <class R, class ... ArgTypes>
+  bool operator==(nullptr_t, const function<R(ArgTypes...)>&) noexcept;
+
+template <class R, class ... ArgTypes>
+  bool operator!=(const function<R(ArgTypes...)>&, nullptr_t) noexcept;
+
+template <class  R, class ... ArgTypes>
+  bool operator!=(nullptr_t, const function<R(ArgTypes...)>&) noexcept;
+
+// specialized algorithms:
+template <class  R, class ... ArgTypes>
+  void swap(function<R(ArgTypes...)>&, function<R(ArgTypes...)>&) noexcept;
+
+template <class T> struct hash;
+
+template <> struct hash<bool>;
+template <> struct hash<char>;
+template <> struct hash<signed char>;
+template <> struct hash<unsigned char>;
+template <> struct hash<char8_t>; // since C++20
+template <> struct hash<char16_t>;
+template <> struct hash<char32_t>;
+template <> struct hash<wchar_t>;
+template <> struct hash<short>;
+template <> struct hash<unsigned short>;
+template <> struct hash<int>;
+template <> struct hash<unsigned int>;
+template <> struct hash<long>;
+template <> struct hash<long long>;
+template <> struct hash<unsigned long>;
+template <> struct hash<unsigned long long>;
+
+template <> struct hash<float>;
+template <> struct hash<double>;
+template <> struct hash<long double>;
+
+template<class T> struct hash<T*>;
+template <> struct hash<nullptr_t>;  // C++17
+
+}  // std
+
+POLICY:  For non-variadic implementations, the number of arguments is limited
+         to 3.  It is hoped that the need for non-variadic implementations
+         will be minimal.
+
+*/
+
+#include <__algorithm/search.h>
+#include <__compare/compare_three_way.h>
+#include <__config>
+#include <__debug>
+#include <__functional/binary_function.h> // TODO: deprecate
+#include <__functional/binary_negate.h>
+#include <__functional/bind_back.h>
+#include <__functional/bind_front.h>
+#include <__functional/bind.h>
+#include <__functional/binder1st.h>
+#include <__functional/binder2nd.h>
+#include <__functional/compose.h>
+#include <__functional/default_searcher.h>
+#include <__functional/function.h>
+#include <__functional/hash.h>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__functional/mem_fn.h> // TODO: deprecate
+#include <__functional/mem_fun_ref.h>
+#include <__functional/not_fn.h>
+#include <__functional/operations.h>
+#include <__functional/pointer_to_binary_function.h>
+#include <__functional/pointer_to_unary_function.h>
+#include <__functional/ranges_operations.h>
+#include <__functional/reference_wrapper.h>
+#include <__functional/unary_function.h> // TODO: deprecate
+#include <__functional/unary_negate.h>
+#include <__functional/unwrap_ref.h>
+#include <__utility/forward.h>
+#include <concepts>
+#include <exception>
+#include <memory>
+#include <tuple>
+#include <type_traits>
+#include <typeinfo>
+#include <utility>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#endif // _LIBCPP_FUNCTIONAL
diff --git a/contrib/libs/cxxsupp/libcxx/include/future b/contrib/libs/cxxsupp/libcxx/include/future
new file mode 100644
index 00000000000..89acdba62bf
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/future
@@ -0,0 +1,2462 @@
+// -*- C++ -*-
+//===--------------------------- future -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_FUTURE
+#define _LIBCPP_FUTURE
+
+/*
+    future synopsis
+
+namespace std
+{
+
+enum class future_errc
+{
+    future_already_retrieved = 1,
+    promise_already_satisfied,
+    no_state,
+    broken_promise
+};
+
+enum class launch
+{
+    async = 1,
+    deferred = 2,
+    any = async | deferred
+};
+
+enum class future_status
+{
+    ready,
+    timeout,
+    deferred
+};
+
+template <> struct is_error_code_enum<future_errc> : public true_type { };
+error_code make_error_code(future_errc e) noexcept;
+error_condition make_error_condition(future_errc e) noexcept;
+
+const error_category& future_category() noexcept;
+
+class future_error
+    : public logic_error
+{
+public:
+    future_error(error_code ec);  // exposition only
+    explicit future_error(future_errc); // C++17
+    const error_code& code() const noexcept;
+    const char*       what() const noexcept;
+};
+
+template <class R>
+class promise
+{
+public:
+    promise();
+    template <class Allocator>
+        promise(allocator_arg_t, const Allocator& a);
+    promise(promise&& rhs) noexcept;
+    promise(const promise& rhs) = delete;
+    ~promise();
+
+    // assignment
+    promise& operator=(promise&& rhs) noexcept;
+    promise& operator=(const promise& rhs) = delete;
+    void swap(promise& other) noexcept;
+
+    // retrieving the result
+    future<R> get_future();
+
+    // setting the result
+    void set_value(const R& r);
+    void set_value(R&& r);
+    void set_exception(exception_ptr p);
+
+    // setting the result with deferred notification
+    void set_value_at_thread_exit(const R& r);
+    void set_value_at_thread_exit(R&& r);
+    void set_exception_at_thread_exit(exception_ptr p);
+};
+
+template <class R>
+class promise<R&>
+{
+public:
+    promise();
+    template <class Allocator>
+        promise(allocator_arg_t, const Allocator& a);
+    promise(promise&& rhs) noexcept;
+    promise(const promise& rhs) = delete;
+    ~promise();
+
+    // assignment
+    promise& operator=(promise&& rhs) noexcept;
+    promise& operator=(const promise& rhs) = delete;
+    void swap(promise& other) noexcept;
+
+    // retrieving the result
+    future<R&> get_future();
+
+    // setting the result
+    void set_value(R& r);
+    void set_exception(exception_ptr p);
+
+    // setting the result with deferred notification
+    void set_value_at_thread_exit(R&);
+    void set_exception_at_thread_exit(exception_ptr p);
+};
+
+template <>
+class promise<void>
+{
+public:
+    promise();
+    template <class Allocator>
+        promise(allocator_arg_t, const Allocator& a);
+    promise(promise&& rhs) noexcept;
+    promise(const promise& rhs) = delete;
+    ~promise();
+
+    // assignment
+    promise& operator=(promise&& rhs) noexcept;
+    promise& operator=(const promise& rhs) = delete;
+    void swap(promise& other) noexcept;
+
+    // retrieving the result
+    future<void> get_future();
+
+    // setting the result
+    void set_value();
+    void set_exception(exception_ptr p);
+
+    // setting the result with deferred notification
+    void set_value_at_thread_exit();
+    void set_exception_at_thread_exit(exception_ptr p);
+};
+
+template <class R> void swap(promise<R>& x, promise<R>& y) noexcept;
+
+template <class R, class Alloc>
+    struct uses_allocator<promise<R>, Alloc> : public true_type {};
+
+template <class R>
+class future
+{
+public:
+    future() noexcept;
+    future(future&&) noexcept;
+    future(const future& rhs) = delete;
+    ~future();
+    future& operator=(const future& rhs) = delete;
+    future& operator=(future&&) noexcept;
+    shared_future<R> share() noexcept;
+
+    // retrieving the value
+    R get();
+
+    // functions to check state
+    bool valid() const noexcept;
+
+    void wait() const;
+    template <class Rep, class Period>
+        future_status
+        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
+    template <class Clock, class Duration>
+        future_status
+        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
+};
+
+template <class R>
+class future<R&>
+{
+public:
+    future() noexcept;
+    future(future&&) noexcept;
+    future(const future& rhs) = delete;
+    ~future();
+    future& operator=(const future& rhs) = delete;
+    future& operator=(future&&) noexcept;
+    shared_future<R&> share() noexcept;
+
+    // retrieving the value
+    R& get();
+
+    // functions to check state
+    bool valid() const noexcept;
+
+    void wait() const;
+    template <class Rep, class Period>
+        future_status
+        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
+    template <class Clock, class Duration>
+        future_status
+        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
+};
+
+template <>
+class future<void>
+{
+public:
+    future() noexcept;
+    future(future&&) noexcept;
+    future(const future& rhs) = delete;
+    ~future();
+    future& operator=(const future& rhs) = delete;
+    future& operator=(future&&) noexcept;
+    shared_future<void> share() noexcept;
+
+    // retrieving the value
+    void get();
+
+    // functions to check state
+    bool valid() const noexcept;
+
+    void wait() const;
+    template <class Rep, class Period>
+        future_status
+        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
+    template <class Clock, class Duration>
+        future_status
+        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
+};
+
+template <class R>
+class shared_future
+{
+public:
+    shared_future() noexcept;
+    shared_future(const shared_future& rhs);
+    shared_future(future<R>&&) noexcept;
+    shared_future(shared_future&& rhs) noexcept;
+    ~shared_future();
+    shared_future& operator=(const shared_future& rhs);
+    shared_future& operator=(shared_future&& rhs) noexcept;
+
+    // retrieving the value
+    const R& get() const;
+
+    // functions to check state
+    bool valid() const noexcept;
+
+    void wait() const;
+    template <class Rep, class Period>
+        future_status
+        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
+    template <class Clock, class Duration>
+        future_status
+        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
+};
+
+template <class R>
+class shared_future<R&>
+{
+public:
+    shared_future() noexcept;
+    shared_future(const shared_future& rhs);
+    shared_future(future<R&>&&) noexcept;
+    shared_future(shared_future&& rhs) noexcept;
+    ~shared_future();
+    shared_future& operator=(const shared_future& rhs);
+    shared_future& operator=(shared_future&& rhs) noexcept;
+
+    // retrieving the value
+    R& get() const;
+
+    // functions to check state
+    bool valid() const noexcept;
+
+    void wait() const;
+    template <class Rep, class Period>
+        future_status
+        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
+    template <class Clock, class Duration>
+        future_status
+        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
+};
+
+template <>
+class shared_future<void>
+{
+public:
+    shared_future() noexcept;
+    shared_future(const shared_future& rhs);
+    shared_future(future<void>&&) noexcept;
+    shared_future(shared_future&& rhs) noexcept;
+    ~shared_future();
+    shared_future& operator=(const shared_future& rhs);
+    shared_future& operator=(shared_future&& rhs) noexcept;
+
+    // retrieving the value
+    void get() const;
+
+    // functions to check state
+    bool valid() const noexcept;
+
+    void wait() const;
+    template <class Rep, class Period>
+        future_status
+        wait_for(const chrono::duration<Rep, Period>& rel_time) const;
+    template <class Clock, class Duration>
+        future_status
+        wait_until(const chrono::time_point<Clock, Duration>& abs_time) const;
+};
+
+template <class F, class... Args>
+  future<typename result_of<typename decay<F>::type(typename decay<Args>::type...)>::type>
+  async(F&& f, Args&&... args);
+
+template <class F, class... Args>
+  future<typename result_of<typename decay<F>::type(typename decay<Args>::type...)>::type>
+  async(launch policy, F&& f, Args&&... args);
+
+template <class> class packaged_task; // undefined
+
+template <class R, class... ArgTypes>
+class packaged_task<R(ArgTypes...)>
+{
+public:
+    typedef R result_type; // extension
+
+    // construction and destruction
+    packaged_task() noexcept;
+    template <class F>
+        explicit packaged_task(F&& f);
+    template <class F, class Allocator>
+        packaged_task(allocator_arg_t, const Allocator& a, F&& f);
+    ~packaged_task();
+
+    // no copy
+    packaged_task(const packaged_task&) = delete;
+    packaged_task& operator=(const packaged_task&) = delete;
+
+    // move support
+    packaged_task(packaged_task&& other) noexcept;
+    packaged_task& operator=(packaged_task&& other) noexcept;
+    void swap(packaged_task& other) noexcept;
+
+    bool valid() const noexcept;
+
+    // result retrieval
+    future<R> get_future();
+
+    // execution
+    void operator()(ArgTypes... );
+    void make_ready_at_thread_exit(ArgTypes...);
+
+    void reset();
+};
+
+template <class R>
+  void swap(packaged_task<R(ArgTypes...)&, packaged_task<R(ArgTypes...)>&) noexcept;
+
+template <class R, class Alloc> struct uses_allocator<packaged_task<R>, Alloc>;
+
+}  // std
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <__debug>
+#include <__memory/allocator_arg_t.h>
+#include <__memory/uses_allocator.h>
+#include <__utility/decay_copy.h>
+#include <__utility/forward.h>
+#include <chrono>
+#include <exception>
+#include <memory>
+#include <mutex>
+#include <system_error>
+#include <thread>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_HAS_NO_THREADS
+#error <future> is not supported on this single threaded system
+#else // !_LIBCPP_HAS_NO_THREADS
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+//enum class future_errc
+_LIBCPP_DECLARE_STRONG_ENUM(future_errc)
+{
+    future_already_retrieved = 1,
+    promise_already_satisfied,
+    no_state,
+    broken_promise
+};
+_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(future_errc)
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS is_error_code_enum<future_errc> : public true_type {};
+
+#ifdef _LIBCPP_HAS_NO_STRONG_ENUMS
+template <>
+struct _LIBCPP_TEMPLATE_VIS is_error_code_enum<future_errc::__lx> : public true_type { };
+#endif
+
+//enum class launch
+_LIBCPP_DECLARE_STRONG_ENUM(launch)
+{
+    async = 1,
+    deferred = 2,
+    any = async | deferred
+};
+_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(launch)
+
+#ifndef _LIBCPP_HAS_NO_STRONG_ENUMS
+
+typedef underlying_type<launch>::type __launch_underlying_type;
+
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+launch
+operator&(launch __x, launch __y)
+{
+    return static_cast<launch>(static_cast<__launch_underlying_type>(__x) &
+                               static_cast<__launch_underlying_type>(__y));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+launch
+operator|(launch __x, launch __y)
+{
+    return static_cast<launch>(static_cast<__launch_underlying_type>(__x) |
+                               static_cast<__launch_underlying_type>(__y));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+launch
+operator^(launch __x, launch __y)
+{
+    return static_cast<launch>(static_cast<__launch_underlying_type>(__x) ^
+                               static_cast<__launch_underlying_type>(__y));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+launch
+operator~(launch __x)
+{
+    return static_cast<launch>(~static_cast<__launch_underlying_type>(__x) & 3);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+launch&
+operator&=(launch& __x, launch __y)
+{
+    __x = __x & __y; return __x;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+launch&
+operator|=(launch& __x, launch __y)
+{
+    __x = __x | __y; return __x;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+launch&
+operator^=(launch& __x, launch __y)
+{
+    __x = __x ^ __y; return __x;
+}
+
+#endif // !_LIBCPP_HAS_NO_STRONG_ENUMS
+
+//enum class future_status
+_LIBCPP_DECLARE_STRONG_ENUM(future_status)
+{
+    ready,
+    timeout,
+    deferred
+};
+_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(future_status)
+
+_LIBCPP_FUNC_VIS
+const error_category& future_category() _NOEXCEPT;
+
+inline _LIBCPP_INLINE_VISIBILITY
+error_code
+make_error_code(future_errc __e) _NOEXCEPT
+{
+    return error_code(static_cast<int>(__e), future_category());
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+error_condition
+make_error_condition(future_errc __e) _NOEXCEPT
+{
+    return error_condition(static_cast<int>(__e), future_category());
+}
+
+class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_FUTURE_ERROR future_error
+    : public logic_error
+{
+    error_code __ec_;
+public:
+    future_error(error_code __ec);
+
+    _LIBCPP_INLINE_VISIBILITY
+    const error_code& code() const _NOEXCEPT {return __ec_;}
+
+    future_error(const future_error&) _NOEXCEPT = default;
+    virtual ~future_error() _NOEXCEPT;
+};
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+#ifndef _LIBCPP_NO_EXCEPTIONS
+_LIBCPP_AVAILABILITY_FUTURE_ERROR
+#endif
+void __throw_future_error(future_errc _Ev)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw future_error(make_error_code(_Ev));
+#else
+    ((void)_Ev);
+    _VSTD::abort();
+#endif
+}
+
+class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_FUTURE __assoc_sub_state
+    : public __shared_count
+{
+protected:
+    exception_ptr __exception_;
+    mutable mutex __mut_;
+    mutable condition_variable __cv_;
+    unsigned __state_;
+
+    virtual void __on_zero_shared() _NOEXCEPT;
+    void __sub_wait(unique_lock<mutex>& __lk);
+public:
+    enum
+    {
+        __constructed = 1,
+        __future_attached = 2,
+        ready = 4,
+        deferred = 8
+    };
+
+    _LIBCPP_INLINE_VISIBILITY
+    __assoc_sub_state() : __state_(0) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool __has_value() const
+        {return (__state_ & __constructed) || (__exception_ != nullptr);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __attach_future() {
+        lock_guard<mutex> __lk(__mut_);
+        bool __has_future_attached = (__state_ & __future_attached) != 0;
+        if (__has_future_attached)
+            __throw_future_error(future_errc::future_already_retrieved);
+        this->__add_shared();
+        __state_ |= __future_attached;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __set_deferred() {__state_ |= deferred;}
+
+    void __make_ready();
+    _LIBCPP_INLINE_VISIBILITY
+    bool __is_ready() const {return (__state_ & ready) != 0;}
+
+    void set_value();
+    void set_value_at_thread_exit();
+
+    void set_exception(exception_ptr __p);
+    void set_exception_at_thread_exit(exception_ptr __p);
+
+    void copy();
+
+    void wait();
+    template <class _Rep, class _Period>
+        future_status
+        _LIBCPP_INLINE_VISIBILITY
+        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const;
+    template <class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        future_status
+        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const;
+
+    virtual void __execute();
+};
+
+template <class _Clock, class _Duration>
+future_status
+__assoc_sub_state::wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
+{
+    unique_lock<mutex> __lk(__mut_);
+    if (__state_ & deferred)
+        return future_status::deferred;
+    while (!(__state_ & ready) && _Clock::now() < __abs_time)
+        __cv_.wait_until(__lk, __abs_time);
+    if (__state_ & ready)
+        return future_status::ready;
+    return future_status::timeout;
+}
+
+template <class _Rep, class _Period>
+inline
+future_status
+__assoc_sub_state::wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
+{
+    return wait_until(chrono::steady_clock::now() + __rel_time);
+}
+
+template <class _Rp>
+class _LIBCPP_AVAILABILITY_FUTURE _LIBCPP_HIDDEN __assoc_state
+    : public __assoc_sub_state
+{
+    typedef __assoc_sub_state base;
+    typedef typename aligned_storage<sizeof(_Rp), alignment_of<_Rp>::value>::type _Up;
+protected:
+    _Up __value_;
+
+    virtual void __on_zero_shared() _NOEXCEPT;
+public:
+
+    template <class _Arg>
+    void set_value(_Arg&& __arg);
+
+    template <class _Arg>
+    void set_value_at_thread_exit(_Arg&& __arg);
+
+    _Rp move();
+    typename add_lvalue_reference<_Rp>::type copy();
+};
+
+template <class _Rp>
+void
+__assoc_state<_Rp>::__on_zero_shared() _NOEXCEPT
+{
+    if (this->__state_ & base::__constructed)
+        reinterpret_cast<_Rp*>(&__value_)->~_Rp();
+    delete this;
+}
+
+template <class _Rp>
+template <class _Arg>
+_LIBCPP_AVAILABILITY_FUTURE
+void
+__assoc_state<_Rp>::set_value(_Arg&& __arg)
+{
+    unique_lock<mutex> __lk(this->__mut_);
+    if (this->__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+    ::new ((void*)&__value_) _Rp(_VSTD::forward<_Arg>(__arg));
+    this->__state_ |= base::__constructed | base::ready;
+    __cv_.notify_all();
+}
+
+template <class _Rp>
+template <class _Arg>
+void
+__assoc_state<_Rp>::set_value_at_thread_exit(_Arg&& __arg)
+{
+    unique_lock<mutex> __lk(this->__mut_);
+    if (this->__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+    ::new ((void*)&__value_) _Rp(_VSTD::forward<_Arg>(__arg));
+    this->__state_ |= base::__constructed;
+    __thread_local_data()->__make_ready_at_thread_exit(this);
+}
+
+template <class _Rp>
+_Rp
+__assoc_state<_Rp>::move()
+{
+    unique_lock<mutex> __lk(this->__mut_);
+    this->__sub_wait(__lk);
+    if (this->__exception_ != nullptr)
+        rethrow_exception(this->__exception_);
+    return _VSTD::move(*reinterpret_cast<_Rp*>(&__value_));
+}
+
+template <class _Rp>
+typename add_lvalue_reference<_Rp>::type
+__assoc_state<_Rp>::copy()
+{
+    unique_lock<mutex> __lk(this->__mut_);
+    this->__sub_wait(__lk);
+    if (this->__exception_ != nullptr)
+        rethrow_exception(this->__exception_);
+    return *reinterpret_cast<_Rp*>(&__value_);
+}
+
+template <class _Rp>
+class _LIBCPP_AVAILABILITY_FUTURE __assoc_state<_Rp&>
+    : public __assoc_sub_state
+{
+    typedef __assoc_sub_state base;
+    typedef _Rp* _Up;
+protected:
+    _Up __value_;
+
+    virtual void __on_zero_shared() _NOEXCEPT;
+public:
+
+    void set_value(_Rp& __arg);
+    void set_value_at_thread_exit(_Rp& __arg);
+
+    _Rp& copy();
+};
+
+template <class _Rp>
+void
+__assoc_state<_Rp&>::__on_zero_shared() _NOEXCEPT
+{
+    delete this;
+}
+
+template <class _Rp>
+void
+__assoc_state<_Rp&>::set_value(_Rp& __arg)
+{
+    unique_lock<mutex> __lk(this->__mut_);
+    if (this->__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+    __value_ = _VSTD::addressof(__arg);
+    this->__state_ |= base::__constructed | base::ready;
+    __cv_.notify_all();
+}
+
+template <class _Rp>
+void
+__assoc_state<_Rp&>::set_value_at_thread_exit(_Rp& __arg)
+{
+    unique_lock<mutex> __lk(this->__mut_);
+    if (this->__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+    __value_ = _VSTD::addressof(__arg);
+    this->__state_ |= base::__constructed;
+    __thread_local_data()->__make_ready_at_thread_exit(this);
+}
+
+template <class _Rp>
+_Rp&
+__assoc_state<_Rp&>::copy()
+{
+    unique_lock<mutex> __lk(this->__mut_);
+    this->__sub_wait(__lk);
+    if (this->__exception_ != nullptr)
+        rethrow_exception(this->__exception_);
+    return *__value_;
+}
+
+template <class _Rp, class _Alloc>
+class _LIBCPP_AVAILABILITY_FUTURE __assoc_state_alloc
+    : public __assoc_state<_Rp>
+{
+    typedef __assoc_state<_Rp> base;
+    _Alloc __alloc_;
+
+    virtual void __on_zero_shared() _NOEXCEPT;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __assoc_state_alloc(const _Alloc& __a)
+        : __alloc_(__a) {}
+};
+
+template <class _Rp, class _Alloc>
+void
+__assoc_state_alloc<_Rp, _Alloc>::__on_zero_shared() _NOEXCEPT
+{
+    if (this->__state_ & base::__constructed)
+        reinterpret_cast<_Rp*>(_VSTD::addressof(this->__value_))->~_Rp();
+    typedef typename __allocator_traits_rebind<_Alloc, __assoc_state_alloc>::type _Al;
+    typedef allocator_traits<_Al> _ATraits;
+    typedef pointer_traits<typename _ATraits::pointer> _PTraits;
+    _Al __a(__alloc_);
+    this->~__assoc_state_alloc();
+    __a.deallocate(_PTraits::pointer_to(*this), 1);
+}
+
+template <class _Rp, class _Alloc>
+class _LIBCPP_AVAILABILITY_FUTURE __assoc_state_alloc<_Rp&, _Alloc>
+    : public __assoc_state<_Rp&>
+{
+    typedef __assoc_state<_Rp&> base;
+    _Alloc __alloc_;
+
+    virtual void __on_zero_shared() _NOEXCEPT;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __assoc_state_alloc(const _Alloc& __a)
+        : __alloc_(__a) {}
+};
+
+template <class _Rp, class _Alloc>
+void
+__assoc_state_alloc<_Rp&, _Alloc>::__on_zero_shared() _NOEXCEPT
+{
+    typedef typename __allocator_traits_rebind<_Alloc, __assoc_state_alloc>::type _Al;
+    typedef allocator_traits<_Al> _ATraits;
+    typedef pointer_traits<typename _ATraits::pointer> _PTraits;
+    _Al __a(__alloc_);
+    this->~__assoc_state_alloc();
+    __a.deallocate(_PTraits::pointer_to(*this), 1);
+}
+
+template <class _Alloc>
+class _LIBCPP_AVAILABILITY_FUTURE __assoc_sub_state_alloc
+    : public __assoc_sub_state
+{
+    typedef __assoc_sub_state base;
+    _Alloc __alloc_;
+
+    virtual void __on_zero_shared() _NOEXCEPT;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __assoc_sub_state_alloc(const _Alloc& __a)
+        : __alloc_(__a) {}
+};
+
+template <class _Alloc>
+void
+__assoc_sub_state_alloc<_Alloc>::__on_zero_shared() _NOEXCEPT
+{
+    typedef typename __allocator_traits_rebind<_Alloc, __assoc_sub_state_alloc>::type _Al;
+    typedef allocator_traits<_Al> _ATraits;
+    typedef pointer_traits<typename _ATraits::pointer> _PTraits;
+    _Al __a(__alloc_);
+    this->~__assoc_sub_state_alloc();
+    __a.deallocate(_PTraits::pointer_to(*this), 1);
+}
+
+template <class _Rp, class _Fp>
+class _LIBCPP_AVAILABILITY_FUTURE __deferred_assoc_state
+    : public __assoc_state<_Rp>
+{
+    typedef __assoc_state<_Rp> base;
+
+    _Fp __func_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __deferred_assoc_state(_Fp&& __f);
+
+    virtual void __execute();
+};
+
+template <class _Rp, class _Fp>
+inline
+__deferred_assoc_state<_Rp, _Fp>::__deferred_assoc_state(_Fp&& __f)
+    : __func_(_VSTD::forward<_Fp>(__f))
+{
+    this->__set_deferred();
+}
+
+template <class _Rp, class _Fp>
+void
+__deferred_assoc_state<_Rp, _Fp>::__execute()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        this->set_value(__func_());
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->set_exception(current_exception());
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template <class _Fp>
+class _LIBCPP_AVAILABILITY_FUTURE __deferred_assoc_state<void, _Fp>
+    : public __assoc_sub_state
+{
+    typedef __assoc_sub_state base;
+
+    _Fp __func_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __deferred_assoc_state(_Fp&& __f);
+
+    virtual void __execute();
+};
+
+template <class _Fp>
+inline
+__deferred_assoc_state<void, _Fp>::__deferred_assoc_state(_Fp&& __f)
+    : __func_(_VSTD::forward<_Fp>(__f))
+{
+    this->__set_deferred();
+}
+
+template <class _Fp>
+void
+__deferred_assoc_state<void, _Fp>::__execute()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __func_();
+        this->set_value();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->set_exception(current_exception());
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template <class _Rp, class _Fp>
+class _LIBCPP_AVAILABILITY_FUTURE __async_assoc_state
+    : public __assoc_state<_Rp>
+{
+    typedef __assoc_state<_Rp> base;
+
+    _Fp __func_;
+
+    virtual void __on_zero_shared() _NOEXCEPT;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __async_assoc_state(_Fp&& __f);
+
+    virtual void __execute();
+};
+
+template <class _Rp, class _Fp>
+inline
+__async_assoc_state<_Rp, _Fp>::__async_assoc_state(_Fp&& __f)
+    : __func_(_VSTD::forward<_Fp>(__f))
+{
+}
+
+template <class _Rp, class _Fp>
+void
+__async_assoc_state<_Rp, _Fp>::__execute()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        this->set_value(__func_());
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->set_exception(current_exception());
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template <class _Rp, class _Fp>
+void
+__async_assoc_state<_Rp, _Fp>::__on_zero_shared() _NOEXCEPT
+{
+    this->wait();
+    base::__on_zero_shared();
+}
+
+template <class _Fp>
+class _LIBCPP_AVAILABILITY_FUTURE __async_assoc_state<void, _Fp>
+    : public __assoc_sub_state
+{
+    typedef __assoc_sub_state base;
+
+    _Fp __func_;
+
+    virtual void __on_zero_shared() _NOEXCEPT;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __async_assoc_state(_Fp&& __f);
+
+    virtual void __execute();
+};
+
+template <class _Fp>
+inline
+__async_assoc_state<void, _Fp>::__async_assoc_state(_Fp&& __f)
+    : __func_(_VSTD::forward<_Fp>(__f))
+{
+}
+
+template <class _Fp>
+void
+__async_assoc_state<void, _Fp>::__execute()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __func_();
+        this->set_value();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->set_exception(current_exception());
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template <class _Fp>
+void
+__async_assoc_state<void, _Fp>::__on_zero_shared() _NOEXCEPT
+{
+    this->wait();
+    base::__on_zero_shared();
+}
+
+template <class _Rp> class _LIBCPP_TEMPLATE_VIS promise;
+template <class _Rp> class _LIBCPP_TEMPLATE_VIS shared_future;
+
+// future
+
+template <class _Rp> class _LIBCPP_TEMPLATE_VIS future;
+
+template <class _Rp, class _Fp>
+_LIBCPP_INLINE_VISIBILITY future<_Rp>
+__make_deferred_assoc_state(_Fp&& __f);
+
+template <class _Rp, class _Fp>
+_LIBCPP_INLINE_VISIBILITY future<_Rp>
+__make_async_assoc_state(_Fp&& __f);
+
+template <class _Rp>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE future
+{
+    __assoc_state<_Rp>* __state_;
+
+    explicit future(__assoc_state<_Rp>* __state);
+
+    template <class> friend class promise;
+    template <class> friend class shared_future;
+
+    template <class _R1, class _Fp>
+        friend future<_R1> __make_deferred_assoc_state(_Fp&& __f);
+    template <class _R1, class _Fp>
+        friend future<_R1> __make_async_assoc_state(_Fp&& __f);
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    future() _NOEXCEPT : __state_(nullptr) {}
+    _LIBCPP_INLINE_VISIBILITY
+    future(future&& __rhs) _NOEXCEPT
+        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
+    future(const future&) = delete;
+    future& operator=(const future&) = delete;
+    _LIBCPP_INLINE_VISIBILITY
+    future& operator=(future&& __rhs) _NOEXCEPT
+        {
+            future(_VSTD::move(__rhs)).swap(*this);
+            return *this;
+        }
+
+    ~future();
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future<_Rp> share() _NOEXCEPT;
+
+    // retrieving the value
+    _Rp get();
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
+
+    // functions to check state
+    _LIBCPP_INLINE_VISIBILITY
+    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void wait() const {__state_->wait();}
+    template <class _Rep, class _Period>
+        _LIBCPP_INLINE_VISIBILITY
+        future_status
+        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
+            {return __state_->wait_for(__rel_time);}
+    template <class _Clock, class _Duration>
+        _LIBCPP_INLINE_VISIBILITY
+        future_status
+        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
+            {return __state_->wait_until(__abs_time);}
+};
+
+template <class _Rp>
+future<_Rp>::future(__assoc_state<_Rp>* __state)
+    : __state_(__state)
+{
+    __state_->__attach_future();
+}
+
+struct __release_shared_count
+{
+    void operator()(__shared_count* p) {p->__release_shared();}
+};
+
+template <class _Rp>
+future<_Rp>::~future()
+{
+    if (__state_)
+        __state_->__release_shared();
+}
+
+template <class _Rp>
+_Rp
+future<_Rp>::get()
+{
+    unique_ptr<__shared_count, __release_shared_count> __(__state_);
+    __assoc_state<_Rp>* __s = __state_;
+    __state_ = nullptr;
+    return __s->move();
+}
+
+template <class _Rp>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE future<_Rp&>
+{
+    __assoc_state<_Rp&>* __state_;
+
+    explicit future(__assoc_state<_Rp&>* __state);
+
+    template <class> friend class promise;
+    template <class> friend class shared_future;
+
+    template <class _R1, class _Fp>
+        friend future<_R1> __make_deferred_assoc_state(_Fp&& __f);
+    template <class _R1, class _Fp>
+        friend future<_R1> __make_async_assoc_state(_Fp&& __f);
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    future() _NOEXCEPT : __state_(nullptr) {}
+    _LIBCPP_INLINE_VISIBILITY
+    future(future&& __rhs) _NOEXCEPT
+        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
+    future(const future&) = delete;
+    future& operator=(const future&) = delete;
+    _LIBCPP_INLINE_VISIBILITY
+    future& operator=(future&& __rhs) _NOEXCEPT
+        {
+            future(_VSTD::move(__rhs)).swap(*this);
+            return *this;
+        }
+
+    ~future();
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future<_Rp&> share() _NOEXCEPT;
+
+    // retrieving the value
+    _Rp& get();
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
+
+    // functions to check state
+    _LIBCPP_INLINE_VISIBILITY
+    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void wait() const {__state_->wait();}
+    template <class _Rep, class _Period>
+        _LIBCPP_INLINE_VISIBILITY
+        future_status
+        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
+            {return __state_->wait_for(__rel_time);}
+    template <class _Clock, class _Duration>
+        _LIBCPP_INLINE_VISIBILITY
+        future_status
+        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
+            {return __state_->wait_until(__abs_time);}
+};
+
+template <class _Rp>
+future<_Rp&>::future(__assoc_state<_Rp&>* __state)
+    : __state_(__state)
+{
+    __state_->__attach_future();
+}
+
+template <class _Rp>
+future<_Rp&>::~future()
+{
+    if (__state_)
+        __state_->__release_shared();
+}
+
+template <class _Rp>
+_Rp&
+future<_Rp&>::get()
+{
+    unique_ptr<__shared_count, __release_shared_count> __(__state_);
+    __assoc_state<_Rp&>* __s = __state_;
+    __state_ = nullptr;
+    return __s->copy();
+}
+
+template <>
+class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_FUTURE future<void>
+{
+    __assoc_sub_state* __state_;
+
+    explicit future(__assoc_sub_state* __state);
+
+    template <class> friend class promise;
+    template <class> friend class shared_future;
+
+    template <class _R1, class _Fp>
+        friend future<_R1> __make_deferred_assoc_state(_Fp&& __f);
+    template <class _R1, class _Fp>
+        friend future<_R1> __make_async_assoc_state(_Fp&& __f);
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    future() _NOEXCEPT : __state_(nullptr) {}
+    _LIBCPP_INLINE_VISIBILITY
+    future(future&& __rhs) _NOEXCEPT
+        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
+    future(const future&) = delete;
+    future& operator=(const future&) = delete;
+    _LIBCPP_INLINE_VISIBILITY
+    future& operator=(future&& __rhs) _NOEXCEPT
+        {
+            future(_VSTD::move(__rhs)).swap(*this);
+            return *this;
+        }
+
+    ~future();
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future<void> share() _NOEXCEPT;
+
+    // retrieving the value
+    void get();
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
+
+    // functions to check state
+    _LIBCPP_INLINE_VISIBILITY
+    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void wait() const {__state_->wait();}
+    template <class _Rep, class _Period>
+        _LIBCPP_INLINE_VISIBILITY
+        future_status
+        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
+            {return __state_->wait_for(__rel_time);}
+    template <class _Clock, class _Duration>
+        _LIBCPP_INLINE_VISIBILITY
+        future_status
+        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
+            {return __state_->wait_until(__abs_time);}
+};
+
+template <class _Rp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(future<_Rp>& __x, future<_Rp>& __y) _NOEXCEPT
+{
+    __x.swap(__y);
+}
+
+// promise<R>
+
+template <class _Callable> class packaged_task;
+
+template <class _Rp>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE promise
+{
+    __assoc_state<_Rp>* __state_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit promise(nullptr_t) _NOEXCEPT : __state_(nullptr) {}
+
+    template <class> friend class packaged_task;
+public:
+    promise();
+    template <class _Alloc>
+        promise(allocator_arg_t, const _Alloc& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    promise(promise&& __rhs) _NOEXCEPT
+        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
+    promise(const promise& __rhs) = delete;
+    ~promise();
+
+    // assignment
+    _LIBCPP_INLINE_VISIBILITY
+    promise& operator=(promise&& __rhs) _NOEXCEPT
+        {
+            promise(_VSTD::move(__rhs)).swap(*this);
+            return *this;
+        }
+    promise& operator=(const promise& __rhs) = delete;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(promise& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
+
+    // retrieving the result
+    future<_Rp> get_future();
+
+    // setting the result
+    void set_value(const _Rp& __r);
+    void set_value(_Rp&& __r);
+    void set_exception(exception_ptr __p);
+
+    // setting the result with deferred notification
+    void set_value_at_thread_exit(const _Rp& __r);
+    void set_value_at_thread_exit(_Rp&& __r);
+    void set_exception_at_thread_exit(exception_ptr __p);
+};
+
+template <class _Rp>
+promise<_Rp>::promise()
+    : __state_(new __assoc_state<_Rp>)
+{
+}
+
+template <class _Rp>
+template <class _Alloc>
+promise<_Rp>::promise(allocator_arg_t, const _Alloc& __a0)
+{
+    typedef __assoc_state_alloc<_Rp, _Alloc> _State;
+    typedef typename __allocator_traits_rebind<_Alloc, _State>::type _A2;
+    typedef __allocator_destructor<_A2> _D2;
+    _A2 __a(__a0);
+    unique_ptr<_State, _D2> __hold(__a.allocate(1), _D2(__a, 1));
+    ::new ((void*)_VSTD::addressof(*__hold.get())) _State(__a0);
+    __state_ = _VSTD::addressof(*__hold.release());
+}
+
+template <class _Rp>
+promise<_Rp>::~promise()
+{
+    if (__state_)
+    {
+        if (!__state_->__has_value() && __state_->use_count() > 1)
+            __state_->set_exception(make_exception_ptr(
+                      future_error(make_error_code(future_errc::broken_promise))
+                                                      ));
+        __state_->__release_shared();
+    }
+}
+
+template <class _Rp>
+future<_Rp>
+promise<_Rp>::get_future()
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    return future<_Rp>(__state_);
+}
+
+template <class _Rp>
+void
+promise<_Rp>::set_value(const _Rp& __r)
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_value(__r);
+}
+
+template <class _Rp>
+void
+promise<_Rp>::set_value(_Rp&& __r)
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_value(_VSTD::move(__r));
+}
+
+template <class _Rp>
+void
+promise<_Rp>::set_exception(exception_ptr __p)
+{
+    _LIBCPP_ASSERT( __p != nullptr, "promise::set_exception: received nullptr" );
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_exception(__p);
+}
+
+template <class _Rp>
+void
+promise<_Rp>::set_value_at_thread_exit(const _Rp& __r)
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_value_at_thread_exit(__r);
+}
+
+template <class _Rp>
+void
+promise<_Rp>::set_value_at_thread_exit(_Rp&& __r)
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_value_at_thread_exit(_VSTD::move(__r));
+}
+
+template <class _Rp>
+void
+promise<_Rp>::set_exception_at_thread_exit(exception_ptr __p)
+{
+    _LIBCPP_ASSERT( __p != nullptr, "promise::set_exception_at_thread_exit: received nullptr" );
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_exception_at_thread_exit(__p);
+}
+
+// promise<R&>
+
+template <class _Rp>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE promise<_Rp&>
+{
+    __assoc_state<_Rp&>* __state_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit promise(nullptr_t) _NOEXCEPT : __state_(nullptr) {}
+
+    template <class> friend class packaged_task;
+
+public:
+    promise();
+    template <class _Allocator>
+        promise(allocator_arg_t, const _Allocator& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    promise(promise&& __rhs) _NOEXCEPT
+        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
+    promise(const promise& __rhs) = delete;
+    ~promise();
+
+    // assignment
+    _LIBCPP_INLINE_VISIBILITY
+    promise& operator=(promise&& __rhs) _NOEXCEPT
+        {
+            promise(_VSTD::move(__rhs)).swap(*this);
+            return *this;
+        }
+    promise& operator=(const promise& __rhs) = delete;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(promise& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
+
+    // retrieving the result
+    future<_Rp&> get_future();
+
+    // setting the result
+    void set_value(_Rp& __r);
+    void set_exception(exception_ptr __p);
+
+    // setting the result with deferred notification
+    void set_value_at_thread_exit(_Rp&);
+    void set_exception_at_thread_exit(exception_ptr __p);
+};
+
+template <class _Rp>
+promise<_Rp&>::promise()
+    : __state_(new __assoc_state<_Rp&>)
+{
+}
+
+template <class _Rp>
+template <class _Alloc>
+promise<_Rp&>::promise(allocator_arg_t, const _Alloc& __a0)
+{
+    typedef __assoc_state_alloc<_Rp&, _Alloc> _State;
+    typedef typename __allocator_traits_rebind<_Alloc, _State>::type _A2;
+    typedef __allocator_destructor<_A2> _D2;
+    _A2 __a(__a0);
+    unique_ptr<_State, _D2> __hold(__a.allocate(1), _D2(__a, 1));
+    ::new ((void*)_VSTD::addressof(*__hold.get())) _State(__a0);
+    __state_ = _VSTD::addressof(*__hold.release());
+}
+
+template <class _Rp>
+promise<_Rp&>::~promise()
+{
+    if (__state_)
+    {
+        if (!__state_->__has_value() && __state_->use_count() > 1)
+            __state_->set_exception(make_exception_ptr(
+                      future_error(make_error_code(future_errc::broken_promise))
+                                                      ));
+        __state_->__release_shared();
+    }
+}
+
+template <class _Rp>
+future<_Rp&>
+promise<_Rp&>::get_future()
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    return future<_Rp&>(__state_);
+}
+
+template <class _Rp>
+void
+promise<_Rp&>::set_value(_Rp& __r)
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_value(__r);
+}
+
+template <class _Rp>
+void
+promise<_Rp&>::set_exception(exception_ptr __p)
+{
+    _LIBCPP_ASSERT( __p != nullptr, "promise::set_exception: received nullptr" );
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_exception(__p);
+}
+
+template <class _Rp>
+void
+promise<_Rp&>::set_value_at_thread_exit(_Rp& __r)
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_value_at_thread_exit(__r);
+}
+
+template <class _Rp>
+void
+promise<_Rp&>::set_exception_at_thread_exit(exception_ptr __p)
+{
+    _LIBCPP_ASSERT( __p != nullptr, "promise::set_exception_at_thread_exit: received nullptr" );
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_exception_at_thread_exit(__p);
+}
+
+// promise<void>
+
+template <>
+class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_FUTURE promise<void>
+{
+    __assoc_sub_state* __state_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit promise(nullptr_t) _NOEXCEPT : __state_(nullptr) {}
+
+    template <class> friend class packaged_task;
+
+public:
+    promise();
+    template <class _Allocator>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        promise(allocator_arg_t, const _Allocator& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    promise(promise&& __rhs) _NOEXCEPT
+        : __state_(__rhs.__state_) {__rhs.__state_ = nullptr;}
+    promise(const promise& __rhs) = delete;
+    ~promise();
+
+    // assignment
+    _LIBCPP_INLINE_VISIBILITY
+    promise& operator=(promise&& __rhs) _NOEXCEPT
+        {
+            promise(_VSTD::move(__rhs)).swap(*this);
+            return *this;
+        }
+    promise& operator=(const promise& __rhs) = delete;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(promise& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
+
+    // retrieving the result
+    future<void> get_future();
+
+    // setting the result
+    void set_value();
+    void set_exception(exception_ptr __p);
+
+    // setting the result with deferred notification
+    void set_value_at_thread_exit();
+    void set_exception_at_thread_exit(exception_ptr __p);
+};
+
+template <class _Alloc>
+promise<void>::promise(allocator_arg_t, const _Alloc& __a0)
+{
+    typedef __assoc_sub_state_alloc<_Alloc> _State;
+    typedef typename __allocator_traits_rebind<_Alloc, _State>::type _A2;
+    typedef __allocator_destructor<_A2> _D2;
+    _A2 __a(__a0);
+    unique_ptr<_State, _D2> __hold(__a.allocate(1), _D2(__a, 1));
+    ::new ((void*)_VSTD::addressof(*__hold.get())) _State(__a0);
+    __state_ = _VSTD::addressof(*__hold.release());
+}
+
+template <class _Rp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(promise<_Rp>& __x, promise<_Rp>& __y) _NOEXCEPT
+{
+    __x.swap(__y);
+}
+
+template <class _Rp, class _Alloc>
+    struct _LIBCPP_TEMPLATE_VIS uses_allocator<promise<_Rp>, _Alloc>
+        : public true_type {};
+
+// packaged_task
+
+template<class _Fp> class __packaged_task_base;
+
+template<class _Rp, class ..._ArgTypes>
+class _LIBCPP_AVAILABILITY_FUTURE __packaged_task_base<_Rp(_ArgTypes...)>
+{
+    __packaged_task_base(const __packaged_task_base&);
+    __packaged_task_base& operator=(const __packaged_task_base&);
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __packaged_task_base() {}
+    _LIBCPP_INLINE_VISIBILITY
+    virtual ~__packaged_task_base() {}
+    virtual void __move_to(__packaged_task_base*) _NOEXCEPT = 0;
+    virtual void destroy() = 0;
+    virtual void destroy_deallocate() = 0;
+    virtual _Rp operator()(_ArgTypes&& ...) = 0;
+};
+
+template<class _FD, class _Alloc, class _FB> class __packaged_task_func;
+
+template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
+class _LIBCPP_AVAILABILITY_FUTURE __packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>
+    : public  __packaged_task_base<_Rp(_ArgTypes...)>
+{
+    __compressed_pair<_Fp, _Alloc> __f_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __packaged_task_func(const _Fp& __f) : __f_(__f, __default_init_tag()) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __packaged_task_func(_Fp&& __f) : __f_(_VSTD::move(__f), __default_init_tag()) {}
+    _LIBCPP_INLINE_VISIBILITY
+    __packaged_task_func(const _Fp& __f, const _Alloc& __a)
+        : __f_(__f, __a) {}
+    _LIBCPP_INLINE_VISIBILITY
+    __packaged_task_func(_Fp&& __f, const _Alloc& __a)
+        : __f_(_VSTD::move(__f), __a) {}
+    virtual void __move_to(__packaged_task_base<_Rp(_ArgTypes...)>*) _NOEXCEPT;
+    virtual void destroy();
+    virtual void destroy_deallocate();
+    virtual _Rp operator()(_ArgTypes&& ... __args);
+};
+
+template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
+void
+__packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::__move_to(
+                              __packaged_task_base<_Rp(_ArgTypes...)>* __p) _NOEXCEPT
+{
+    ::new ((void*)__p) __packaged_task_func(_VSTD::move(__f_.first()), _VSTD::move(__f_.second()));
+}
+
+template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
+void
+__packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::destroy()
+{
+    __f_.~__compressed_pair<_Fp, _Alloc>();
+}
+
+template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
+void
+__packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::destroy_deallocate()
+{
+    typedef typename __allocator_traits_rebind<_Alloc, __packaged_task_func>::type _Ap;
+    typedef allocator_traits<_Ap> _ATraits;
+    typedef pointer_traits<typename _ATraits::pointer> _PTraits;
+    _Ap __a(__f_.second());
+    __f_.~__compressed_pair<_Fp, _Alloc>();
+    __a.deallocate(_PTraits::pointer_to(*this), 1);
+}
+
+template<class _Fp, class _Alloc, class _Rp, class ..._ArgTypes>
+_Rp
+__packaged_task_func<_Fp, _Alloc, _Rp(_ArgTypes...)>::operator()(_ArgTypes&& ... __arg)
+{
+    return _VSTD::__invoke(__f_.first(), _VSTD::forward<_ArgTypes>(__arg)...);
+}
+
+template <class _Callable> class __packaged_task_function;
+
+template<class _Rp, class ..._ArgTypes>
+class _LIBCPP_AVAILABILITY_FUTURE __packaged_task_function<_Rp(_ArgTypes...)>
+{
+    typedef __packaged_task_base<_Rp(_ArgTypes...)> __base;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_NO_CFI
+    __base* __get_buf() { return (__base*)&__buf_; }
+
+    typename aligned_storage<3*sizeof(void*)>::type __buf_;
+    __base* __f_;
+
+public:
+    typedef _Rp result_type;
+
+    // construct/copy/destroy:
+    _LIBCPP_INLINE_VISIBILITY
+    __packaged_task_function() _NOEXCEPT : __f_(nullptr) {}
+    template<class _Fp>
+      __packaged_task_function(_Fp&& __f);
+    template<class _Fp, class _Alloc>
+      __packaged_task_function(allocator_arg_t, const _Alloc& __a, _Fp&& __f);
+
+    __packaged_task_function(__packaged_task_function&&) _NOEXCEPT;
+    __packaged_task_function& operator=(__packaged_task_function&&) _NOEXCEPT;
+
+    __packaged_task_function(const __packaged_task_function&) =  delete;
+    __packaged_task_function& operator=(const __packaged_task_function&) =  delete;
+
+    ~__packaged_task_function();
+
+    void swap(__packaged_task_function&) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Rp operator()(_ArgTypes...) const;
+};
+
+template<class _Rp, class ..._ArgTypes>
+__packaged_task_function<_Rp(_ArgTypes...)>::__packaged_task_function(__packaged_task_function&& __f) _NOEXCEPT
+{
+    if (__f.__f_ == nullptr)
+        __f_ = nullptr;
+    else if (__f.__f_ == __f.__get_buf())
+    {
+        __f.__f_->__move_to(__get_buf());
+        __f_ = (__base*)&__buf_;
+    }
+    else
+    {
+        __f_ = __f.__f_;
+        __f.__f_ = nullptr;
+    }
+}
+
+template<class _Rp, class ..._ArgTypes>
+template <class _Fp>
+__packaged_task_function<_Rp(_ArgTypes...)>::__packaged_task_function(_Fp&& __f)
+    : __f_(nullptr)
+{
+    typedef typename remove_reference<typename decay<_Fp>::type>::type _FR;
+    typedef __packaged_task_func<_FR, allocator<_FR>, _Rp(_ArgTypes...)> _FF;
+    if (sizeof(_FF) <= sizeof(__buf_))
+    {
+        ::new ((void*)&__buf_) _FF(_VSTD::forward<_Fp>(__f));
+        __f_ = (__base*)&__buf_;
+    }
+    else
+    {
+        typedef allocator<_FF> _Ap;
+        _Ap __a;
+        typedef __allocator_destructor<_Ap> _Dp;
+        unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+        ::new ((void*)__hold.get()) _FF(_VSTD::forward<_Fp>(__f), allocator<_FR>(__a));
+        __f_ = __hold.release();
+    }
+}
+
+template<class _Rp, class ..._ArgTypes>
+template <class _Fp, class _Alloc>
+__packaged_task_function<_Rp(_ArgTypes...)>::__packaged_task_function(
+                                  allocator_arg_t, const _Alloc& __a0, _Fp&& __f)
+    : __f_(nullptr)
+{
+    typedef typename remove_reference<typename decay<_Fp>::type>::type _FR;
+    typedef __packaged_task_func<_FR, _Alloc, _Rp(_ArgTypes...)> _FF;
+    if (sizeof(_FF) <= sizeof(__buf_))
+    {
+        __f_ = (__base*)&__buf_;
+        ::new ((void*)__f_) _FF(_VSTD::forward<_Fp>(__f));
+    }
+    else
+    {
+        typedef typename __allocator_traits_rebind<_Alloc, _FF>::type _Ap;
+        _Ap __a(__a0);
+        typedef __allocator_destructor<_Ap> _Dp;
+        unique_ptr<__base, _Dp> __hold(__a.allocate(1), _Dp(__a, 1));
+        ::new ((void*)_VSTD::addressof(*__hold.get()))
+            _FF(_VSTD::forward<_Fp>(__f), _Alloc(__a));
+        __f_ = _VSTD::addressof(*__hold.release());
+    }
+}
+
+template<class _Rp, class ..._ArgTypes>
+__packaged_task_function<_Rp(_ArgTypes...)>&
+__packaged_task_function<_Rp(_ArgTypes...)>::operator=(__packaged_task_function&& __f) _NOEXCEPT
+{
+    if (__f_ == __get_buf())
+        __f_->destroy();
+    else if (__f_)
+        __f_->destroy_deallocate();
+    __f_ = nullptr;
+    if (__f.__f_ == nullptr)
+        __f_ = nullptr;
+    else if (__f.__f_ == __f.__get_buf())
+    {
+        __f.__f_->__move_to(__get_buf());
+        __f_ = __get_buf();
+    }
+    else
+    {
+        __f_ = __f.__f_;
+        __f.__f_ = nullptr;
+    }
+    return *this;
+}
+
+template<class _Rp, class ..._ArgTypes>
+__packaged_task_function<_Rp(_ArgTypes...)>::~__packaged_task_function()
+{
+    if (__f_ == __get_buf())
+        __f_->destroy();
+    else if (__f_)
+        __f_->destroy_deallocate();
+}
+
+template<class _Rp, class ..._ArgTypes>
+_LIBCPP_NO_CFI
+void
+__packaged_task_function<_Rp(_ArgTypes...)>::swap(__packaged_task_function& __f) _NOEXCEPT
+{
+    if (__f_ == (__base*)&__buf_ && __f.__f_ == (__base*)&__f.__buf_)
+    {
+        typename aligned_storage<sizeof(__buf_)>::type __tempbuf;
+        __base* __t = (__base*)&__tempbuf;
+        __f_->__move_to(__t);
+        __f_->destroy();
+        __f_ = nullptr;
+        __f.__f_->__move_to((__base*)&__buf_);
+        __f.__f_->destroy();
+        __f.__f_ = nullptr;
+        __f_ = (__base*)&__buf_;
+        __t->__move_to((__base*)&__f.__buf_);
+        __t->destroy();
+        __f.__f_ = (__base*)&__f.__buf_;
+    }
+    else if (__f_ == (__base*)&__buf_)
+    {
+        __f_->__move_to((__base*)&__f.__buf_);
+        __f_->destroy();
+        __f_ = __f.__f_;
+        __f.__f_ = (__base*)&__f.__buf_;
+    }
+    else if (__f.__f_ == (__base*)&__f.__buf_)
+    {
+        __f.__f_->__move_to((__base*)&__buf_);
+        __f.__f_->destroy();
+        __f.__f_ = __f_;
+        __f_ = (__base*)&__buf_;
+    }
+    else
+        _VSTD::swap(__f_, __f.__f_);
+}
+
+template<class _Rp, class ..._ArgTypes>
+inline
+_Rp
+__packaged_task_function<_Rp(_ArgTypes...)>::operator()(_ArgTypes... __arg) const
+{
+    return (*__f_)(_VSTD::forward<_ArgTypes>(__arg)...);
+}
+
+template<class _Rp, class ..._ArgTypes>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE packaged_task<_Rp(_ArgTypes...)>
+{
+public:
+    typedef _Rp result_type; // extension
+
+private:
+    __packaged_task_function<result_type(_ArgTypes...)> __f_;
+    promise<result_type>                                __p_;
+
+public:
+    // construction and destruction
+    _LIBCPP_INLINE_VISIBILITY
+    packaged_task() _NOEXCEPT : __p_(nullptr) {}
+    template <class _Fp,
+              class = typename enable_if
+              <
+                  !is_same<
+                      typename __uncvref<_Fp>::type,
+                      packaged_task
+                      >::value
+                  >::type
+             >
+        _LIBCPP_INLINE_VISIBILITY
+        explicit packaged_task(_Fp&& __f) : __f_(_VSTD::forward<_Fp>(__f)) {}
+    template <class _Fp, class _Allocator,
+              class = typename enable_if
+              <
+                  !is_same<
+                      typename __uncvref<_Fp>::type,
+                      packaged_task
+                      >::value
+                  >::type
+              >
+        _LIBCPP_INLINE_VISIBILITY
+        packaged_task(allocator_arg_t, const _Allocator& __a, _Fp&& __f)
+             : __f_(allocator_arg, __a, _VSTD::forward<_Fp>(__f)),
+               __p_(allocator_arg, __a) {}
+    // ~packaged_task() = default;
+
+    // no copy
+    packaged_task(const packaged_task&) = delete;
+    packaged_task& operator=(const packaged_task&) = delete;
+
+    // move support
+    _LIBCPP_INLINE_VISIBILITY
+    packaged_task(packaged_task&& __other) _NOEXCEPT
+        : __f_(_VSTD::move(__other.__f_)), __p_(_VSTD::move(__other.__p_)) {}
+    _LIBCPP_INLINE_VISIBILITY
+    packaged_task& operator=(packaged_task&& __other) _NOEXCEPT
+    {
+        __f_ = _VSTD::move(__other.__f_);
+        __p_ = _VSTD::move(__other.__p_);
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(packaged_task& __other) _NOEXCEPT
+    {
+        __f_.swap(__other.__f_);
+        __p_.swap(__other.__p_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool valid() const _NOEXCEPT {return __p_.__state_ != nullptr;}
+
+    // result retrieval
+    _LIBCPP_INLINE_VISIBILITY
+    future<result_type> get_future() {return __p_.get_future();}
+
+    // execution
+    void operator()(_ArgTypes... __args);
+    void make_ready_at_thread_exit(_ArgTypes... __args);
+
+    void reset();
+};
+
+template<class _Rp, class ..._ArgTypes>
+void
+packaged_task<_Rp(_ArgTypes...)>::operator()(_ArgTypes... __args)
+{
+    if (__p_.__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    if (__p_.__state_->__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __p_.set_value(__f_(_VSTD::forward<_ArgTypes>(__args)...));
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __p_.set_exception(current_exception());
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template<class _Rp, class ..._ArgTypes>
+void
+packaged_task<_Rp(_ArgTypes...)>::make_ready_at_thread_exit(_ArgTypes... __args)
+{
+    if (__p_.__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    if (__p_.__state_->__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __p_.set_value_at_thread_exit(__f_(_VSTD::forward<_ArgTypes>(__args)...));
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __p_.set_exception_at_thread_exit(current_exception());
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template<class _Rp, class ..._ArgTypes>
+void
+packaged_task<_Rp(_ArgTypes...)>::reset()
+{
+    if (!valid())
+        __throw_future_error(future_errc::no_state);
+    __p_ = promise<result_type>();
+}
+
+template<class ..._ArgTypes>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FUTURE packaged_task<void(_ArgTypes...)>
+{
+public:
+    typedef void result_type; // extension
+
+private:
+    __packaged_task_function<result_type(_ArgTypes...)> __f_;
+    promise<result_type>                                __p_;
+
+public:
+    // construction and destruction
+    _LIBCPP_INLINE_VISIBILITY
+    packaged_task() _NOEXCEPT : __p_(nullptr) {}
+    template <class _Fp,
+              class = typename enable_if
+              <
+                  !is_same<
+                      typename __uncvref<_Fp>::type,
+                      packaged_task
+                      >::value
+                  >::type
+              >
+        _LIBCPP_INLINE_VISIBILITY
+        explicit packaged_task(_Fp&& __f) : __f_(_VSTD::forward<_Fp>(__f)) {}
+    template <class _Fp, class _Allocator,
+              class = typename enable_if
+              <
+                  !is_same<
+                      typename __uncvref<_Fp>::type,
+                      packaged_task
+                      >::value
+                  >::type
+              >
+        _LIBCPP_INLINE_VISIBILITY
+        packaged_task(allocator_arg_t, const _Allocator& __a, _Fp&& __f)
+             : __f_(allocator_arg, __a, _VSTD::forward<_Fp>(__f)),
+               __p_(allocator_arg, __a) {}
+    // ~packaged_task() = default;
+
+    // no copy
+    packaged_task(const packaged_task&) = delete;
+    packaged_task& operator=(const packaged_task&) = delete;
+
+    // move support
+    _LIBCPP_INLINE_VISIBILITY
+    packaged_task(packaged_task&& __other) _NOEXCEPT
+        : __f_(_VSTD::move(__other.__f_)), __p_(_VSTD::move(__other.__p_)) {}
+    _LIBCPP_INLINE_VISIBILITY
+    packaged_task& operator=(packaged_task&& __other) _NOEXCEPT
+    {
+        __f_ = _VSTD::move(__other.__f_);
+        __p_ = _VSTD::move(__other.__p_);
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(packaged_task& __other) _NOEXCEPT
+    {
+        __f_.swap(__other.__f_);
+        __p_.swap(__other.__p_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool valid() const _NOEXCEPT {return __p_.__state_ != nullptr;}
+
+    // result retrieval
+    _LIBCPP_INLINE_VISIBILITY
+    future<result_type> get_future() {return __p_.get_future();}
+
+    // execution
+    void operator()(_ArgTypes... __args);
+    void make_ready_at_thread_exit(_ArgTypes... __args);
+
+    void reset();
+};
+
+template<class ..._ArgTypes>
+void
+packaged_task<void(_ArgTypes...)>::operator()(_ArgTypes... __args)
+{
+    if (__p_.__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    if (__p_.__state_->__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __f_(_VSTD::forward<_ArgTypes>(__args)...);
+        __p_.set_value();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __p_.set_exception(current_exception());
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template<class ..._ArgTypes>
+void
+packaged_task<void(_ArgTypes...)>::make_ready_at_thread_exit(_ArgTypes... __args)
+{
+    if (__p_.__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    if (__p_.__state_->__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __f_(_VSTD::forward<_ArgTypes>(__args)...);
+        __p_.set_value_at_thread_exit();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __p_.set_exception_at_thread_exit(current_exception());
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template<class ..._ArgTypes>
+void
+packaged_task<void(_ArgTypes...)>::reset()
+{
+    if (!valid())
+        __throw_future_error(future_errc::no_state);
+    __p_ = promise<result_type>();
+}
+
+template <class _Rp, class... _ArgTypes>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(packaged_task<_Rp(_ArgTypes...)>& __x, packaged_task<_Rp(_ArgTypes...)>& __y) _NOEXCEPT
+{
+    __x.swap(__y);
+}
+
+template <class _Callable, class _Alloc>
+struct _LIBCPP_TEMPLATE_VIS uses_allocator<packaged_task<_Callable>, _Alloc>
+    : public true_type {};
+
+template <class _Rp, class _Fp>
+_LIBCPP_INLINE_VISIBILITY future<_Rp>
+__make_deferred_assoc_state(_Fp&& __f)
+{
+    unique_ptr<__deferred_assoc_state<_Rp, _Fp>, __release_shared_count>
+        __h(new __deferred_assoc_state<_Rp, _Fp>(_VSTD::forward<_Fp>(__f)));
+    return future<_Rp>(__h.get());
+}
+
+template <class _Rp, class _Fp>
+_LIBCPP_INLINE_VISIBILITY future<_Rp>
+__make_async_assoc_state(_Fp&& __f)
+{
+    unique_ptr<__async_assoc_state<_Rp, _Fp>, __release_shared_count>
+        __h(new __async_assoc_state<_Rp, _Fp>(_VSTD::forward<_Fp>(__f)));
+    _VSTD::thread(&__async_assoc_state<_Rp, _Fp>::__execute, __h.get()).detach();
+    return future<_Rp>(__h.get());
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Fp, class... _Args>
+class _LIBCPP_HIDDEN __async_func
+{
+    tuple<_Fp, _Args...> __f_;
+
+public:
+    typedef typename __invoke_of<_Fp, _Args...>::type _Rp;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __async_func(_Fp&& __f, _Args&&... __args)
+        : __f_(_VSTD::move(__f), _VSTD::move(__args)...) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __async_func(__async_func&& __f) : __f_(_VSTD::move(__f.__f_)) {}
+
+    _Rp operator()()
+    {
+        typedef typename __make_tuple_indices<1+sizeof...(_Args), 1>::type _Index;
+        return __execute(_Index());
+    }
+private:
+    template <size_t ..._Indices>
+    _Rp
+    __execute(__tuple_indices<_Indices...>)
+    {
+        return _VSTD::__invoke(_VSTD::move(_VSTD::get<0>(__f_)), _VSTD::move(_VSTD::get<_Indices>(__f_))...);
+    }
+};
+
+inline _LIBCPP_INLINE_VISIBILITY bool __does_policy_contain(launch __policy, launch __value )
+{ return (int(__policy) & int(__value)) != 0; }
+
+template <class _Fp, class... _Args>
+_LIBCPP_NODISCARD_AFTER_CXX17
+future<typename __invoke_of<typename decay<_Fp>::type, typename decay<_Args>::type...>::type>
+async(launch __policy, _Fp&& __f, _Args&&... __args)
+{
+    typedef __async_func<typename decay<_Fp>::type, typename decay<_Args>::type...> _BF;
+    typedef typename _BF::_Rp _Rp;
+
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif
+        if (__does_policy_contain(__policy, launch::async))
+        return _VSTD::__make_async_assoc_state<_Rp>(_BF(_VSTD::__decay_copy(_VSTD::forward<_Fp>(__f)),
+                                                     _VSTD::__decay_copy(_VSTD::forward<_Args>(__args))...));
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch ( ... ) { if (__policy == launch::async) throw ; }
+#endif
+
+    if (__does_policy_contain(__policy, launch::deferred))
+        return _VSTD::__make_deferred_assoc_state<_Rp>(_BF(_VSTD::__decay_copy(_VSTD::forward<_Fp>(__f)),
+                                                        _VSTD::__decay_copy(_VSTD::forward<_Args>(__args))...));
+    return future<_Rp>{};
+}
+
+template <class _Fp, class... _Args>
+_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_INLINE_VISIBILITY
+future<typename __invoke_of<typename decay<_Fp>::type, typename decay<_Args>::type...>::type>
+async(_Fp&& __f, _Args&&... __args)
+{
+    return _VSTD::async(launch::any, _VSTD::forward<_Fp>(__f),
+                                    _VSTD::forward<_Args>(__args)...);
+}
+
+#endif // C++03
+
+// shared_future
+
+template <class _Rp>
+class _LIBCPP_TEMPLATE_VIS shared_future
+{
+    __assoc_state<_Rp>* __state_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future() _NOEXCEPT : __state_(nullptr) {}
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future(const shared_future& __rhs)  _NOEXCEPT : __state_(__rhs.__state_)
+        {if (__state_) __state_->__add_shared();}
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future(future<_Rp>&& __f) _NOEXCEPT : __state_(__f.__state_)
+        {__f.__state_ = nullptr;}
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future(shared_future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_)
+        {__rhs.__state_ = nullptr;}
+    ~shared_future();
+    shared_future& operator=(const shared_future& __rhs) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future& operator=(shared_future&& __rhs) _NOEXCEPT
+        {
+            shared_future(_VSTD::move(__rhs)).swap(*this);
+            return *this;
+        }
+
+    // retrieving the value
+    _LIBCPP_INLINE_VISIBILITY
+    const _Rp& get() const {return __state_->copy();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(shared_future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
+
+    // functions to check state
+    _LIBCPP_INLINE_VISIBILITY
+    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void wait() const {__state_->wait();}
+    template <class _Rep, class _Period>
+        _LIBCPP_INLINE_VISIBILITY
+        future_status
+        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
+            {return __state_->wait_for(__rel_time);}
+    template <class _Clock, class _Duration>
+        _LIBCPP_INLINE_VISIBILITY
+        future_status
+        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
+            {return __state_->wait_until(__abs_time);}
+};
+
+template <class _Rp>
+shared_future<_Rp>::~shared_future()
+{
+    if (__state_)
+        __state_->__release_shared();
+}
+
+template <class _Rp>
+shared_future<_Rp>&
+shared_future<_Rp>::operator=(const shared_future& __rhs) _NOEXCEPT
+{
+    if (__rhs.__state_)
+        __rhs.__state_->__add_shared();
+    if (__state_)
+        __state_->__release_shared();
+    __state_ = __rhs.__state_;
+    return *this;
+}
+
+template <class _Rp>
+class _LIBCPP_TEMPLATE_VIS shared_future<_Rp&>
+{
+    __assoc_state<_Rp&>* __state_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future() _NOEXCEPT : __state_(nullptr) {}
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future(const shared_future& __rhs) : __state_(__rhs.__state_)
+        {if (__state_) __state_->__add_shared();}
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future(future<_Rp&>&& __f) _NOEXCEPT : __state_(__f.__state_)
+        {__f.__state_ = nullptr;}
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future(shared_future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_)
+        {__rhs.__state_ = nullptr;}
+    ~shared_future();
+    shared_future& operator=(const shared_future& __rhs);
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future& operator=(shared_future&& __rhs) _NOEXCEPT
+        {
+            shared_future(_VSTD::move(__rhs)).swap(*this);
+            return *this;
+        }
+
+    // retrieving the value
+    _LIBCPP_INLINE_VISIBILITY
+    _Rp& get() const {return __state_->copy();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(shared_future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
+
+    // functions to check state
+    _LIBCPP_INLINE_VISIBILITY
+    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void wait() const {__state_->wait();}
+    template <class _Rep, class _Period>
+        _LIBCPP_INLINE_VISIBILITY
+        future_status
+        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
+            {return __state_->wait_for(__rel_time);}
+    template <class _Clock, class _Duration>
+        _LIBCPP_INLINE_VISIBILITY
+        future_status
+        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
+            {return __state_->wait_until(__abs_time);}
+};
+
+template <class _Rp>
+shared_future<_Rp&>::~shared_future()
+{
+    if (__state_)
+        __state_->__release_shared();
+}
+
+template <class _Rp>
+shared_future<_Rp&>&
+shared_future<_Rp&>::operator=(const shared_future& __rhs)
+{
+    if (__rhs.__state_)
+        __rhs.__state_->__add_shared();
+    if (__state_)
+        __state_->__release_shared();
+    __state_ = __rhs.__state_;
+    return *this;
+}
+
+template <>
+class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_FUTURE shared_future<void>
+{
+    __assoc_sub_state* __state_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future() _NOEXCEPT : __state_(nullptr) {}
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future(const shared_future& __rhs) : __state_(__rhs.__state_)
+        {if (__state_) __state_->__add_shared();}
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future(future<void>&& __f) _NOEXCEPT : __state_(__f.__state_)
+        {__f.__state_ = nullptr;}
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future(shared_future&& __rhs) _NOEXCEPT : __state_(__rhs.__state_)
+        {__rhs.__state_ = nullptr;}
+    ~shared_future();
+    shared_future& operator=(const shared_future& __rhs);
+    _LIBCPP_INLINE_VISIBILITY
+    shared_future& operator=(shared_future&& __rhs) _NOEXCEPT
+        {
+            shared_future(_VSTD::move(__rhs)).swap(*this);
+            return *this;
+        }
+
+    // retrieving the value
+    _LIBCPP_INLINE_VISIBILITY
+    void get() const {__state_->copy();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(shared_future& __rhs) _NOEXCEPT {_VSTD::swap(__state_, __rhs.__state_);}
+
+    // functions to check state
+    _LIBCPP_INLINE_VISIBILITY
+    bool valid() const _NOEXCEPT {return __state_ != nullptr;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void wait() const {__state_->wait();}
+    template <class _Rep, class _Period>
+        _LIBCPP_INLINE_VISIBILITY
+        future_status
+        wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const
+            {return __state_->wait_for(__rel_time);}
+    template <class _Clock, class _Duration>
+        _LIBCPP_INLINE_VISIBILITY
+        future_status
+        wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const
+            {return __state_->wait_until(__abs_time);}
+};
+
+template <class _Rp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(shared_future<_Rp>& __x, shared_future<_Rp>& __y) _NOEXCEPT
+{
+    __x.swap(__y);
+}
+
+template <class _Rp>
+inline
+shared_future<_Rp>
+future<_Rp>::share() _NOEXCEPT
+{
+    return shared_future<_Rp>(_VSTD::move(*this));
+}
+
+template <class _Rp>
+inline
+shared_future<_Rp&>
+future<_Rp&>::share() _NOEXCEPT
+{
+    return shared_future<_Rp&>(_VSTD::move(*this));
+}
+
+inline
+shared_future<void>
+future<void>::share() _NOEXCEPT
+{
+    return shared_future<void>(_VSTD::move(*this));
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !_LIBCPP_HAS_NO_THREADS
+
+#endif // _LIBCPP_FUTURE
diff --git a/contrib/libs/cxxsupp/libcxx/include/initializer_list b/contrib/libs/cxxsupp/libcxx/include/initializer_list
new file mode 100644
index 00000000000..89502392ab5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/initializer_list
@@ -0,0 +1,131 @@
+// -*- C++ -*-
+//===----------------------- initializer_list -----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_INITIALIZER_LIST
+#define _LIBCPP_INITIALIZER_LIST
+
+/*
+    initializer_list synopsis
+
+namespace std
+{
+
+template<class E>
+class initializer_list
+{
+public:
+    typedef E        value_type;
+    typedef const E& reference;
+    typedef const E& const_reference;
+    typedef size_t   size_type;
+
+    typedef const E* iterator;
+    typedef const E* const_iterator;
+
+    initializer_list() noexcept; // constexpr in C++14
+
+    size_t   size()  const noexcept; // constexpr in C++14
+    const E* begin() const noexcept; // constexpr in C++14
+    const E* end()   const noexcept; // constexpr in C++14
+};
+
+template<class E> const E* begin(initializer_list<E> il) noexcept; // constexpr in C++14
+template<class E> const E* end(initializer_list<E> il) noexcept; // constexpr in C++14
+
+}  // std
+
+*/
+
+#include <__config>
+#include <cstddef>
+
+#if defined(_LIBCPP_COMPILER_MSVC) && !defined(__clang__)
+
+#include _LIBCPP_MSVC_INCLUDE(yvals.h)
+#include _LIBCPP_MSVC_INCLUDE(initializer_list)
+
+#else
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+namespace std  // purposefully not versioned
+{
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _Ep>
+class _LIBCPP_TEMPLATE_VIS initializer_list
+{
+    const _Ep* __begin_;
+    size_t    __size_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX11
+    initializer_list(const _Ep* __b, size_t __s) _NOEXCEPT
+        : __begin_(__b),
+          __size_(__s)
+        {}
+public:
+    typedef _Ep        value_type;
+    typedef const _Ep& reference;
+    typedef const _Ep& const_reference;
+    typedef size_t    size_type;
+
+    typedef const _Ep* iterator;
+    typedef const _Ep* const_iterator;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX11
+    initializer_list() _NOEXCEPT : __begin_(nullptr), __size_(0) {}
+
+    initializer_list(const initializer_list&) = default;
+    initializer_list(initializer_list&&) = default;
+    initializer_list& operator=(const initializer_list&) = delete;
+    initializer_list& operator=(initializer_list&&) = delete;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX11
+    size_t    size()  const _NOEXCEPT {return __size_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const _Ep* begin() const _NOEXCEPT {return __begin_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const _Ep* end()   const _NOEXCEPT {return __begin_ + __size_;}
+};
+
+template<class _Ep>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX11
+const _Ep*
+begin(initializer_list<_Ep> __il) _NOEXCEPT
+{
+    return __il.begin();
+}
+
+template<class _Ep>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX11
+const _Ep*
+end(initializer_list<_Ep> __il) _NOEXCEPT
+{
+    return __il.end();
+}
+
+#endif // !defined(_LIBCPP_CXX03_LANG)
+
+}  // std
+
+#endif // _LIBCPP_COMPILER_MSVC
+
+#endif // _LIBCPP_INITIALIZER_LIST
diff --git a/contrib/libs/cxxsupp/libcxx/include/inttypes.h b/contrib/libs/cxxsupp/libcxx/include/inttypes.h
new file mode 100644
index 00000000000..6f8021263ea
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/inttypes.h
@@ -0,0 +1,266 @@
+// -*- C++ -*-
+//===--------------------------- inttypes.h -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_INTTYPES_H
+// AIX system headers need inttypes.h to be re-enterable while _STD_TYPES_T
+// is defined until an inclusion of it without _STD_TYPES_T occurs, in which
+// case the header guard macro is defined.
+#if !defined(_AIX) || !defined(_STD_TYPES_T)
+#define _LIBCPP_INTTYPES_H
+#endif // _STD_TYPES_T
+
+/*
+    inttypes.h synopsis
+
+This entire header is C99 / C++0X
+
+#include <stdint.h>  // <cinttypes> includes <cstdint>
+
+Macros:
+
+    PRId8
+    PRId16
+    PRId32
+    PRId64
+
+    PRIdLEAST8
+    PRIdLEAST16
+    PRIdLEAST32
+    PRIdLEAST64
+
+    PRIdFAST8
+    PRIdFAST16
+    PRIdFAST32
+    PRIdFAST64
+
+    PRIdMAX
+    PRIdPTR
+
+    PRIi8
+    PRIi16
+    PRIi32
+    PRIi64
+
+    PRIiLEAST8
+    PRIiLEAST16
+    PRIiLEAST32
+    PRIiLEAST64
+
+    PRIiFAST8
+    PRIiFAST16
+    PRIiFAST32
+    PRIiFAST64
+
+    PRIiMAX
+    PRIiPTR
+
+    PRIo8
+    PRIo16
+    PRIo32
+    PRIo64
+
+    PRIoLEAST8
+    PRIoLEAST16
+    PRIoLEAST32
+    PRIoLEAST64
+
+    PRIoFAST8
+    PRIoFAST16
+    PRIoFAST32
+    PRIoFAST64
+
+    PRIoMAX
+    PRIoPTR
+
+    PRIu8
+    PRIu16
+    PRIu32
+    PRIu64
+
+    PRIuLEAST8
+    PRIuLEAST16
+    PRIuLEAST32
+    PRIuLEAST64
+
+    PRIuFAST8
+    PRIuFAST16
+    PRIuFAST32
+    PRIuFAST64
+
+    PRIuMAX
+    PRIuPTR
+
+    PRIx8
+    PRIx16
+    PRIx32
+    PRIx64
+
+    PRIxLEAST8
+    PRIxLEAST16
+    PRIxLEAST32
+    PRIxLEAST64
+
+    PRIxFAST8
+    PRIxFAST16
+    PRIxFAST32
+    PRIxFAST64
+
+    PRIxMAX
+    PRIxPTR
+
+    PRIX8
+    PRIX16
+    PRIX32
+    PRIX64
+
+    PRIXLEAST8
+    PRIXLEAST16
+    PRIXLEAST32
+    PRIXLEAST64
+
+    PRIXFAST8
+    PRIXFAST16
+    PRIXFAST32
+    PRIXFAST64
+
+    PRIXMAX
+    PRIXPTR
+
+    SCNd8
+    SCNd16
+    SCNd32
+    SCNd64
+
+    SCNdLEAST8
+    SCNdLEAST16
+    SCNdLEAST32
+    SCNdLEAST64
+
+    SCNdFAST8
+    SCNdFAST16
+    SCNdFAST32
+    SCNdFAST64
+
+    SCNdMAX
+    SCNdPTR
+
+    SCNi8
+    SCNi16
+    SCNi32
+    SCNi64
+
+    SCNiLEAST8
+    SCNiLEAST16
+    SCNiLEAST32
+    SCNiLEAST64
+
+    SCNiFAST8
+    SCNiFAST16
+    SCNiFAST32
+    SCNiFAST64
+
+    SCNiMAX
+    SCNiPTR
+
+    SCNo8
+    SCNo16
+    SCNo32
+    SCNo64
+
+    SCNoLEAST8
+    SCNoLEAST16
+    SCNoLEAST32
+    SCNoLEAST64
+
+    SCNoFAST8
+    SCNoFAST16
+    SCNoFAST32
+    SCNoFAST64
+
+    SCNoMAX
+    SCNoPTR
+
+    SCNu8
+    SCNu16
+    SCNu32
+    SCNu64
+
+    SCNuLEAST8
+    SCNuLEAST16
+    SCNuLEAST32
+    SCNuLEAST64
+
+    SCNuFAST8
+    SCNuFAST16
+    SCNuFAST32
+    SCNuFAST64
+
+    SCNuMAX
+    SCNuPTR
+
+    SCNx8
+    SCNx16
+    SCNx32
+    SCNx64
+
+    SCNxLEAST8
+    SCNxLEAST16
+    SCNxLEAST32
+    SCNxLEAST64
+
+    SCNxFAST8
+    SCNxFAST16
+    SCNxFAST32
+    SCNxFAST64
+
+    SCNxMAX
+    SCNxPTR
+
+Types:
+
+    imaxdiv_t
+
+intmax_t  imaxabs(intmax_t j);
+imaxdiv_t imaxdiv(intmax_t numer, intmax_t denom);
+intmax_t  strtoimax(const char* restrict nptr, char** restrict endptr, int base);
+uintmax_t strtoumax(const char* restrict nptr, char** restrict endptr, int base);
+intmax_t  wcstoimax(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);
+uintmax_t wcstoumax(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+/* C99 stdlib (e.g. glibc < 2.18) does not provide format macros needed
+   for C++11 unless __STDC_FORMAT_MACROS is defined
+*/
+#if defined(__cplusplus) && !defined(__STDC_FORMAT_MACROS)
+#   define __STDC_FORMAT_MACROS
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(inttypes.h)
+#else
+#include_next <inttypes.h>
+#endif
+
+#ifdef __cplusplus
+
+#include <stdint.h>
+
+#undef imaxabs
+#undef imaxdiv
+
+#endif // __cplusplus
+
+#endif // _LIBCPP_INTTYPES_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/iomanip b/contrib/libs/cxxsupp/libcxx/include/iomanip
new file mode 100644
index 00000000000..47d573b5fc8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/iomanip
@@ -0,0 +1,670 @@
+// -*- C++ -*-
+//===--------------------------- iomanip ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_IOMANIP
+#define _LIBCPP_IOMANIP
+
+/*
+    iomanip synopsis
+
+namespace std {
+
+// types T1, T2, ... are unspecified implementation types
+T1 resetiosflags(ios_base::fmtflags mask);
+T2 setiosflags (ios_base::fmtflags mask);
+T3 setbase(int base);
+template<charT> T4 setfill(charT c);
+T5 setprecision(int n);
+T6 setw(int n);
+template <class moneyT> T7 get_money(moneyT& mon, bool intl = false);
+template <class charT, class moneyT> T8 put_money(const moneyT& mon, bool intl = false);
+template <class charT> T9 get_time(struct tm* tmb, const charT* fmt);
+template <class charT> T10 put_time(const struct tm* tmb, const charT* fmt);
+
+template <class charT>
+  T11 quoted(const charT* s, charT delim=charT('"'), charT escape=charT('\\')); // C++14
+
+template <class charT, class traits, class Allocator>
+  T12 quoted(const basic_string<charT, traits, Allocator>& s,
+             charT delim=charT('"'), charT escape=charT('\\')); // C++14
+
+template <class charT, class traits, class Allocator>
+  T13 quoted(basic_string<charT, traits, Allocator>& s,
+             charT delim=charT('"'), charT escape=charT('\\')); // C++14
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__string>
+#include <istream>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// resetiosflags
+
+class __iom_t1
+{
+    ios_base::fmtflags __mask_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __iom_t1(ios_base::fmtflags __m) : __mask_(__m) {}
+
+    template <class _CharT, class _Traits>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, const __iom_t1& __x)
+    {
+        __is.unsetf(__x.__mask_);
+        return __is;
+    }
+
+    template <class _CharT, class _Traits>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, const __iom_t1& __x)
+    {
+        __os.unsetf(__x.__mask_);
+        return __os;
+    }
+};
+
+inline _LIBCPP_INLINE_VISIBILITY
+__iom_t1
+resetiosflags(ios_base::fmtflags __mask)
+{
+    return __iom_t1(__mask);
+}
+
+// setiosflags
+
+class __iom_t2
+{
+    ios_base::fmtflags __mask_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __iom_t2(ios_base::fmtflags __m) : __mask_(__m) {}
+
+    template <class _CharT, class _Traits>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, const __iom_t2& __x)
+    {
+        __is.setf(__x.__mask_);
+        return __is;
+    }
+
+    template <class _CharT, class _Traits>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, const __iom_t2& __x)
+    {
+        __os.setf(__x.__mask_);
+        return __os;
+    }
+};
+
+inline _LIBCPP_INLINE_VISIBILITY
+__iom_t2
+setiosflags(ios_base::fmtflags __mask)
+{
+    return __iom_t2(__mask);
+}
+
+// setbase
+
+class __iom_t3
+{
+    int __base_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __iom_t3(int __b) : __base_(__b) {}
+
+    template <class _CharT, class _Traits>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, const __iom_t3& __x)
+    {
+        __is.setf(__x.__base_ == 8  ? ios_base::oct :
+                  __x.__base_ == 10 ? ios_base::dec :
+                  __x.__base_ == 16 ? ios_base::hex :
+                  ios_base::fmtflags(0), ios_base::basefield);
+        return __is;
+    }
+
+    template <class _CharT, class _Traits>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, const __iom_t3& __x)
+    {
+        __os.setf(__x.__base_ == 8  ? ios_base::oct :
+                  __x.__base_ == 10 ? ios_base::dec :
+                  __x.__base_ == 16 ? ios_base::hex :
+                  ios_base::fmtflags(0), ios_base::basefield);
+        return __os;
+    }
+};
+
+inline _LIBCPP_INLINE_VISIBILITY
+__iom_t3
+setbase(int __base)
+{
+    return __iom_t3(__base);
+}
+
+// setfill
+
+template<class _CharT>
+class __iom_t4
+{
+    _CharT __fill_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __iom_t4(_CharT __c) : __fill_(__c) {}
+
+    template <class _Traits>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, const __iom_t4& __x)
+    {
+        __os.fill(__x.__fill_);
+        return __os;
+    }
+};
+
+template<class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+__iom_t4<_CharT>
+setfill(_CharT __c)
+{
+    return __iom_t4<_CharT>(__c);
+}
+
+// setprecision
+
+class __iom_t5
+{
+    int __n_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __iom_t5(int __n) : __n_(__n) {}
+
+    template <class _CharT, class _Traits>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, const __iom_t5& __x)
+    {
+        __is.precision(__x.__n_);
+        return __is;
+    }
+
+    template <class _CharT, class _Traits>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, const __iom_t5& __x)
+    {
+        __os.precision(__x.__n_);
+        return __os;
+    }
+};
+
+inline _LIBCPP_INLINE_VISIBILITY
+__iom_t5
+setprecision(int __n)
+{
+    return __iom_t5(__n);
+}
+
+// setw
+
+class __iom_t6
+{
+    int __n_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __iom_t6(int __n) : __n_(__n) {}
+
+    template <class _CharT, class _Traits>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, const __iom_t6& __x)
+    {
+        __is.width(__x.__n_);
+        return __is;
+    }
+
+    template <class _CharT, class _Traits>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, const __iom_t6& __x)
+    {
+        __os.width(__x.__n_);
+        return __os;
+    }
+};
+
+inline _LIBCPP_INLINE_VISIBILITY
+__iom_t6
+setw(int __n)
+{
+    return __iom_t6(__n);
+}
+
+// get_money
+
+template <class _MoneyT> class __iom_t7;
+
+template <class _CharT, class _Traits, class _MoneyT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, const __iom_t7<_MoneyT>& __x);
+
+template <class _MoneyT>
+class __iom_t7
+{
+    _MoneyT& __mon_;
+    bool __intl_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __iom_t7(_MoneyT& __mon, bool __intl)
+        : __mon_(__mon), __intl_(__intl) {}
+
+    template <class _CharT, class _Traits, class _Mp>
+    friend
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is, const __iom_t7<_Mp>& __x);
+};
+
+template <class _CharT, class _Traits, class _MoneyT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, const __iom_t7<_MoneyT>& __x)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        typename basic_istream<_CharT, _Traits>::sentry __s(__is);
+        if (__s)
+        {
+            typedef istreambuf_iterator<_CharT, _Traits> _Ip;
+            typedef money_get<_CharT, _Ip> _Fp;
+            ios_base::iostate __err = ios_base::goodbit;
+            const _Fp& __mf = use_facet<_Fp>(__is.getloc());
+            __mf.get(_Ip(__is), _Ip(), __x.__intl_, __is, __err, __x.__mon_);
+            __is.setstate(__err);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __is.__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return __is;
+}
+
+template <class _MoneyT>
+inline _LIBCPP_INLINE_VISIBILITY
+__iom_t7<_MoneyT>
+get_money(_MoneyT& __mon, bool __intl = false)
+{
+    return __iom_t7<_MoneyT>(__mon, __intl);
+}
+
+// put_money
+
+template <class _MoneyT> class __iom_t8;
+
+template <class _CharT, class _Traits, class _MoneyT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const __iom_t8<_MoneyT>& __x);
+
+template <class _MoneyT>
+class __iom_t8
+{
+    const _MoneyT& __mon_;
+    bool __intl_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __iom_t8(const _MoneyT& __mon, bool __intl)
+        : __mon_(__mon), __intl_(__intl) {}
+
+    template <class _CharT, class _Traits, class _Mp>
+    friend
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os, const __iom_t8<_Mp>& __x);
+};
+
+template <class _CharT, class _Traits, class _MoneyT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const __iom_t8<_MoneyT>& __x)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        typename basic_ostream<_CharT, _Traits>::sentry __s(__os);
+        if (__s)
+        {
+            typedef ostreambuf_iterator<_CharT, _Traits> _Op;
+            typedef money_put<_CharT, _Op> _Fp;
+            const _Fp& __mf = use_facet<_Fp>(__os.getloc());
+            if (__mf.put(_Op(__os), __x.__intl_, __os, __os.fill(), __x.__mon_).failed())
+                __os.setstate(ios_base::badbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __os.__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return __os;
+}
+
+template <class _MoneyT>
+inline _LIBCPP_INLINE_VISIBILITY
+__iom_t8<_MoneyT>
+put_money(const _MoneyT& __mon, bool __intl = false)
+{
+    return __iom_t8<_MoneyT>(__mon, __intl);
+}
+
+// get_time
+
+template <class _CharT> class __iom_t9;
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, const __iom_t9<_CharT>& __x);
+
+template <class _CharT>
+class __iom_t9
+{
+    tm* __tm_;
+    const _CharT* __fmt_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __iom_t9(tm* __tm, const _CharT* __fmt)
+        : __tm_(__tm), __fmt_(__fmt) {}
+
+    template <class _Cp, class _Traits>
+    friend
+    basic_istream<_Cp, _Traits>&
+    operator>>(basic_istream<_Cp, _Traits>& __is, const __iom_t9<_Cp>& __x);
+};
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, const __iom_t9<_CharT>& __x)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        typename basic_istream<_CharT, _Traits>::sentry __s(__is);
+        if (__s)
+        {
+            typedef istreambuf_iterator<_CharT, _Traits> _Ip;
+            typedef time_get<_CharT, _Ip> _Fp;
+            ios_base::iostate __err = ios_base::goodbit;
+            const _Fp& __tf = use_facet<_Fp>(__is.getloc());
+            __tf.get(_Ip(__is), _Ip(), __is, __err, __x.__tm_,
+                     __x.__fmt_, __x.__fmt_ + _Traits::length(__x.__fmt_));
+            __is.setstate(__err);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __is.__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return __is;
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+__iom_t9<_CharT>
+get_time(tm* __tm, const _CharT* __fmt)
+{
+    return __iom_t9<_CharT>(__tm, __fmt);
+}
+
+// put_time
+
+template <class _CharT> class __iom_t10;
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const __iom_t10<_CharT>& __x);
+
+template <class _CharT>
+class __iom_t10
+{
+    const tm* __tm_;
+    const _CharT* __fmt_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __iom_t10(const tm* __tm, const _CharT* __fmt)
+        : __tm_(__tm), __fmt_(__fmt) {}
+
+    template <class _Cp, class _Traits>
+    friend
+    basic_ostream<_Cp, _Traits>&
+    operator<<(basic_ostream<_Cp, _Traits>& __os, const __iom_t10<_Cp>& __x);
+};
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const __iom_t10<_CharT>& __x)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        typename basic_ostream<_CharT, _Traits>::sentry __s(__os);
+        if (__s)
+        {
+            typedef ostreambuf_iterator<_CharT, _Traits> _Op;
+            typedef time_put<_CharT, _Op> _Fp;
+            const _Fp& __tf = use_facet<_Fp>(__os.getloc());
+            if (__tf.put(_Op(__os), __os, __os.fill(), __x.__tm_,
+                         __x.__fmt_, __x.__fmt_ + _Traits::length(__x.__fmt_)).failed())
+                __os.setstate(ios_base::badbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __os.__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return __os;
+}
+
+template <class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+__iom_t10<_CharT>
+put_time(const tm* __tm, const _CharT* __fmt)
+{
+    return __iom_t10<_CharT>(__tm, __fmt);
+}
+
+template <class _CharT, class _Traits, class _ForwardIterator>
+basic_ostream<_CharT, _Traits> &
+__quoted_output ( basic_ostream<_CharT, _Traits> &__os,
+        _ForwardIterator __first, _ForwardIterator __last, _CharT __delim, _CharT __escape )
+{
+    basic_string<_CharT, _Traits> __str;
+    __str.push_back(__delim);
+    for ( ; __first != __last; ++ __first )
+    {
+        if (_Traits::eq (*__first, __escape) || _Traits::eq (*__first, __delim))
+            __str.push_back(__escape);
+        __str.push_back(*__first);
+    }
+    __str.push_back(__delim);
+    return _VSTD::__put_character_sequence(__os, __str.data(), __str.size());
+}
+
+template <class _CharT, class _Traits, class _String>
+basic_istream<_CharT, _Traits> &
+__quoted_input ( basic_istream<_CharT, _Traits> &__is, _String & __string, _CharT __delim, _CharT __escape )
+{
+    __string.clear ();
+    _CharT __c;
+    __is >> __c;
+    if ( __is.fail ())
+        return __is;
+
+    if (!_Traits::eq (__c, __delim))    // no delimiter, read the whole string
+    {
+        __is.unget ();
+        __is >> __string;
+        return __is;
+    }
+
+    __save_flags<_CharT, _Traits> sf(__is);
+    noskipws (__is);
+    while (true)
+        {
+        __is >> __c;
+        if ( __is.fail ())
+            break;
+        if (_Traits::eq (__c, __escape))
+        {
+            __is >> __c;
+            if ( __is.fail ())
+                break;
+        }
+        else if (_Traits::eq (__c, __delim))
+            break;
+        __string.push_back ( __c );
+        }
+    return __is;
+}
+
+
+template <class _CharT, class _Traits, class _Iter>
+basic_ostream<_CharT, _Traits>& operator<<(
+         basic_ostream<_CharT, _Traits>& __os,
+         const __quoted_output_proxy<_CharT, _Iter, _Traits> & __proxy)
+{
+    return __quoted_output (__os, __proxy.__first, __proxy.__last, __proxy.__delim, __proxy.__escape);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+struct __quoted_proxy
+{
+    basic_string<_CharT, _Traits, _Allocator> &__string;
+    _CharT  __delim;
+    _CharT  __escape;
+
+    __quoted_proxy(basic_string<_CharT, _Traits, _Allocator> &__s, _CharT __d, _CharT __e)
+    : __string(__s), __delim(__d), __escape(__e) {}
+};
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_INLINE_VISIBILITY
+basic_ostream<_CharT, _Traits>& operator<<(
+        basic_ostream<_CharT, _Traits>& __os,
+        const __quoted_proxy<_CharT, _Traits, _Allocator> & __proxy)
+{
+    return __quoted_output (__os, __proxy.__string.cbegin (), __proxy.__string.cend (), __proxy.__delim, __proxy.__escape);
+}
+
+//  extractor for non-const basic_string& proxies
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_INLINE_VISIBILITY
+basic_istream<_CharT, _Traits>& operator>>(
+        basic_istream<_CharT, _Traits>& __is,
+        const __quoted_proxy<_CharT, _Traits, _Allocator> & __proxy)
+{
+    return __quoted_input ( __is, __proxy.__string, __proxy.__delim, __proxy.__escape );
+}
+
+
+template <class _CharT>
+_LIBCPP_INLINE_VISIBILITY
+__quoted_output_proxy<_CharT, const _CharT *>
+quoted ( const _CharT *__s, _CharT __delim = _CharT('"'), _CharT __escape =_CharT('\\'))
+{
+    const _CharT *__end = __s;
+    while ( *__end ) ++__end;
+    return __quoted_output_proxy<_CharT, const _CharT *> ( __s, __end, __delim, __escape );
+}
+
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_INLINE_VISIBILITY
+__quoted_output_proxy<_CharT, typename basic_string <_CharT, _Traits, _Allocator>::const_iterator>
+__quoted ( const basic_string <_CharT, _Traits, _Allocator> &__s, _CharT __delim = _CharT('"'), _CharT __escape=_CharT('\\'))
+{
+    return __quoted_output_proxy<_CharT,
+            typename basic_string <_CharT, _Traits, _Allocator>::const_iterator>
+                    ( __s.cbegin(), __s.cend (), __delim, __escape );
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_INLINE_VISIBILITY
+__quoted_proxy<_CharT, _Traits, _Allocator>
+__quoted ( basic_string <_CharT, _Traits, _Allocator> &__s, _CharT __delim = _CharT('"'), _CharT __escape=_CharT('\\'))
+{
+    return __quoted_proxy<_CharT, _Traits, _Allocator>( __s, __delim, __escape );
+}
+
+
+#if _LIBCPP_STD_VER > 11
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_INLINE_VISIBILITY
+__quoted_output_proxy<_CharT, typename basic_string <_CharT, _Traits, _Allocator>::const_iterator>
+quoted ( const basic_string <_CharT, _Traits, _Allocator> &__s, _CharT __delim = _CharT('"'), _CharT __escape=_CharT('\\'))
+{
+    return __quoted(__s, __delim, __escape);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+_LIBCPP_INLINE_VISIBILITY
+__quoted_proxy<_CharT, _Traits, _Allocator>
+quoted ( basic_string <_CharT, _Traits, _Allocator> &__s, _CharT __delim = _CharT('"'), _CharT __escape=_CharT('\\'))
+{
+    return __quoted(__s, __delim, __escape);
+}
+
+template <class _CharT, class _Traits>
+__quoted_output_proxy<_CharT, const _CharT *, _Traits>
+quoted (basic_string_view <_CharT, _Traits> __sv,
+             _CharT __delim = _CharT('"'), _CharT __escape=_CharT('\\'))
+{
+    return __quoted_output_proxy<_CharT, const _CharT *, _Traits>
+         ( __sv.data(), __sv.data() + __sv.size(), __delim, __escape );
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_IOMANIP
diff --git a/contrib/libs/cxxsupp/libcxx/include/ios b/contrib/libs/cxxsupp/libcxx/include/ios
new file mode 100644
index 00000000000..c9230d6a948
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/ios
@@ -0,0 +1,1028 @@
+// -*- C++ -*-
+//===---------------------------- ios -------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_IOS
+#define _LIBCPP_IOS
+
+/*
+    ios synopsis
+
+#include <iosfwd>
+
+namespace std
+{
+
+typedef OFF_T streamoff;
+typedef SZ_T streamsize;
+template <class stateT> class fpos;
+
+class ios_base
+{
+public:
+    class failure;
+
+    typedef T1 fmtflags;
+    static constexpr fmtflags boolalpha;
+    static constexpr fmtflags dec;
+    static constexpr fmtflags fixed;
+    static constexpr fmtflags hex;
+    static constexpr fmtflags internal;
+    static constexpr fmtflags left;
+    static constexpr fmtflags oct;
+    static constexpr fmtflags right;
+    static constexpr fmtflags scientific;
+    static constexpr fmtflags showbase;
+    static constexpr fmtflags showpoint;
+    static constexpr fmtflags showpos;
+    static constexpr fmtflags skipws;
+    static constexpr fmtflags unitbuf;
+    static constexpr fmtflags uppercase;
+    static constexpr fmtflags adjustfield;
+    static constexpr fmtflags basefield;
+    static constexpr fmtflags floatfield;
+
+    typedef T2 iostate;
+    static constexpr iostate badbit;
+    static constexpr iostate eofbit;
+    static constexpr iostate failbit;
+    static constexpr iostate goodbit;
+
+    typedef T3 openmode;
+    static constexpr openmode app;
+    static constexpr openmode ate;
+    static constexpr openmode binary;
+    static constexpr openmode in;
+    static constexpr openmode out;
+    static constexpr openmode trunc;
+
+    typedef T4 seekdir;
+    static constexpr seekdir beg;
+    static constexpr seekdir cur;
+    static constexpr seekdir end;
+
+    class Init;
+
+    // 27.5.2.2 fmtflags state:
+    fmtflags flags() const;
+    fmtflags flags(fmtflags fmtfl);
+    fmtflags setf(fmtflags fmtfl);
+    fmtflags setf(fmtflags fmtfl, fmtflags mask);
+    void unsetf(fmtflags mask);
+
+    streamsize precision() const;
+    streamsize precision(streamsize prec);
+    streamsize width() const;
+    streamsize width(streamsize wide);
+
+    // 27.5.2.3 locales:
+    locale imbue(const locale& loc);
+    locale getloc() const;
+
+    // 27.5.2.5 storage:
+    static int xalloc();
+    long& iword(int index);
+    void*& pword(int index);
+
+    // destructor
+    virtual ~ios_base();
+
+    // 27.5.2.6 callbacks;
+    enum event { erase_event, imbue_event, copyfmt_event };
+    typedef void (*event_callback)(event, ios_base&, int index);
+    void register_callback(event_callback fn, int index);
+
+    ios_base(const ios_base&) = delete;
+    ios_base& operator=(const ios_base&) = delete;
+
+    static bool sync_with_stdio(bool sync = true);
+
+protected:
+    ios_base();
+};
+
+template <class charT, class traits = char_traits<charT> >
+class basic_ios
+    : public ios_base
+{
+public:
+    // types:
+    typedef charT char_type;
+    typedef typename traits::int_type int_type;  // removed in C++17
+    typedef typename traits::pos_type pos_type;  // removed in C++17
+    typedef typename traits::off_type off_type;  // removed in C++17
+    typedef traits traits_type;
+
+    operator unspecified-bool-type() const;
+    bool operator!() const;
+    iostate rdstate() const;
+    void clear(iostate state = goodbit);
+    void setstate(iostate state);
+    bool good() const;
+    bool eof() const;
+    bool fail() const;
+    bool bad() const;
+
+    iostate exceptions() const;
+    void exceptions(iostate except);
+
+    // 27.5.4.1 Constructor/destructor:
+    explicit basic_ios(basic_streambuf<charT,traits>* sb);
+    virtual ~basic_ios();
+
+    // 27.5.4.2 Members:
+    basic_ostream<charT,traits>* tie() const;
+    basic_ostream<charT,traits>* tie(basic_ostream<charT,traits>* tiestr);
+
+    basic_streambuf<charT,traits>* rdbuf() const;
+    basic_streambuf<charT,traits>* rdbuf(basic_streambuf<charT,traits>* sb);
+
+    basic_ios& copyfmt(const basic_ios& rhs);
+
+    char_type fill() const;
+    char_type fill(char_type ch);
+
+    locale imbue(const locale& loc);
+
+    char narrow(char_type c, char dfault) const;
+    char_type widen(char c) const;
+
+    basic_ios(const basic_ios& ) = delete;
+    basic_ios& operator=(const basic_ios&) = delete;
+
+protected:
+    basic_ios();
+    void init(basic_streambuf<charT,traits>* sb);
+    void move(basic_ios& rhs);
+    void swap(basic_ios& rhs) noexcept;
+    void set_rdbuf(basic_streambuf<charT, traits>* sb);
+};
+
+// 27.5.5, manipulators:
+ios_base& boolalpha (ios_base& str);
+ios_base& noboolalpha(ios_base& str);
+ios_base& showbase (ios_base& str);
+ios_base& noshowbase (ios_base& str);
+ios_base& showpoint (ios_base& str);
+ios_base& noshowpoint(ios_base& str);
+ios_base& showpos (ios_base& str);
+ios_base& noshowpos (ios_base& str);
+ios_base& skipws (ios_base& str);
+ios_base& noskipws (ios_base& str);
+ios_base& uppercase (ios_base& str);
+ios_base& nouppercase(ios_base& str);
+ios_base& unitbuf (ios_base& str);
+ios_base& nounitbuf (ios_base& str);
+
+// 27.5.5.2 adjustfield:
+ios_base& internal (ios_base& str);
+ios_base& left (ios_base& str);
+ios_base& right (ios_base& str);
+
+// 27.5.5.3 basefield:
+ios_base& dec (ios_base& str);
+ios_base& hex (ios_base& str);
+ios_base& oct (ios_base& str);
+
+// 27.5.5.4 floatfield:
+ios_base& fixed (ios_base& str);
+ios_base& scientific (ios_base& str);
+ios_base& hexfloat (ios_base& str);
+ios_base& defaultfloat(ios_base& str);
+
+// 27.5.5.5 error reporting:
+enum class io_errc
+{
+    stream = 1
+};
+
+concept_map ErrorCodeEnum<io_errc> { };
+error_code make_error_code(io_errc e) noexcept;
+error_condition make_error_condition(io_errc e) noexcept;
+storage-class-specifier const error_category& iostream_category() noexcept;
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__locale>
+#include <iosfwd>
+#include <system_error>
+
+#if !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
+#include <atomic>     // for __xindex_
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+typedef ptrdiff_t streamsize;
+
+class _LIBCPP_TYPE_VIS ios_base
+{
+public:
+    class _LIBCPP_EXCEPTION_ABI failure;
+
+    typedef unsigned int fmtflags;
+    static const fmtflags boolalpha   = 0x0001;
+    static const fmtflags dec         = 0x0002;
+    static const fmtflags fixed       = 0x0004;
+    static const fmtflags hex         = 0x0008;
+    static const fmtflags internal    = 0x0010;
+    static const fmtflags left        = 0x0020;
+    static const fmtflags oct         = 0x0040;
+    static const fmtflags right       = 0x0080;
+    static const fmtflags scientific  = 0x0100;
+    static const fmtflags showbase    = 0x0200;
+    static const fmtflags showpoint   = 0x0400;
+    static const fmtflags showpos     = 0x0800;
+    static const fmtflags skipws      = 0x1000;
+    static const fmtflags unitbuf     = 0x2000;
+    static const fmtflags uppercase   = 0x4000;
+    static const fmtflags adjustfield = left | right | internal;
+    static const fmtflags basefield   = dec | oct | hex;
+    static const fmtflags floatfield  = scientific | fixed;
+
+    typedef unsigned int iostate;
+    static const iostate badbit  = 0x1;
+    static const iostate eofbit  = 0x2;
+    static const iostate failbit = 0x4;
+    static const iostate goodbit = 0x0;
+
+    typedef unsigned int openmode;
+    static const openmode app    = 0x01;
+    static const openmode ate    = 0x02;
+    static const openmode binary = 0x04;
+    static const openmode in     = 0x08;
+    static const openmode out    = 0x10;
+    static const openmode trunc  = 0x20;
+
+    enum seekdir {beg, cur, end};
+
+#if _LIBCPP_STD_VER <= 14
+    typedef iostate      io_state;
+    typedef openmode     open_mode;
+    typedef seekdir      seek_dir;
+
+    typedef _VSTD::streamoff streamoff;
+    typedef _VSTD::streampos streampos;
+#endif
+
+    class _LIBCPP_TYPE_VIS Init;
+
+    // 27.5.2.2 fmtflags state:
+    _LIBCPP_INLINE_VISIBILITY fmtflags flags() const;
+    _LIBCPP_INLINE_VISIBILITY fmtflags flags(fmtflags __fmtfl);
+    _LIBCPP_INLINE_VISIBILITY fmtflags setf(fmtflags __fmtfl);
+    _LIBCPP_INLINE_VISIBILITY fmtflags setf(fmtflags __fmtfl, fmtflags __mask);
+    _LIBCPP_INLINE_VISIBILITY void unsetf(fmtflags __mask);
+
+    _LIBCPP_INLINE_VISIBILITY streamsize precision() const;
+    _LIBCPP_INLINE_VISIBILITY streamsize precision(streamsize __prec);
+    _LIBCPP_INLINE_VISIBILITY streamsize width() const;
+    _LIBCPP_INLINE_VISIBILITY streamsize width(streamsize __wide);
+
+    // 27.5.2.3 locales:
+    locale imbue(const locale& __loc);
+    locale getloc() const;
+
+    // 27.5.2.5 storage:
+    static int xalloc();
+    long& iword(int __index);
+    void*& pword(int __index);
+
+    // destructor
+    virtual ~ios_base();
+
+    // 27.5.2.6 callbacks;
+    enum event { erase_event, imbue_event, copyfmt_event };
+    typedef void (*event_callback)(event, ios_base&, int __index);
+    void register_callback(event_callback __fn, int __index);
+
+private:
+    ios_base(const ios_base&); // = delete;
+    ios_base& operator=(const ios_base&); // = delete;
+
+public:
+    static bool sync_with_stdio(bool __sync = true);
+
+    _LIBCPP_INLINE_VISIBILITY iostate rdstate() const;
+    void clear(iostate __state = goodbit);
+    _LIBCPP_INLINE_VISIBILITY void setstate(iostate __state);
+
+    _LIBCPP_INLINE_VISIBILITY bool good() const;
+    _LIBCPP_INLINE_VISIBILITY bool eof() const;
+    _LIBCPP_INLINE_VISIBILITY bool fail() const;
+    _LIBCPP_INLINE_VISIBILITY bool bad() const;
+
+    _LIBCPP_INLINE_VISIBILITY iostate exceptions() const;
+    _LIBCPP_INLINE_VISIBILITY void exceptions(iostate __iostate);
+
+    void __set_badbit_and_consider_rethrow();
+    void __set_failbit_and_consider_rethrow();
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __setstate_nothrow(iostate __state)
+    {
+        if (__rdbuf_)
+            __rdstate_ |= __state;
+        else
+            __rdstate_ |= __state | ios_base::badbit;
+    }
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    ios_base() {// purposefully does no initialization
+               }
+
+    void init(void* __sb);
+    _LIBCPP_INLINE_VISIBILITY void* rdbuf() const {return __rdbuf_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void rdbuf(void* __sb)
+    {
+        __rdbuf_ = __sb;
+        clear();
+    }
+
+    void __call_callbacks(event);
+    void copyfmt(const ios_base&);
+    void move(ios_base&);
+    void swap(ios_base&) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void set_rdbuf(void* __sb)
+    {
+        __rdbuf_ = __sb;
+    }
+
+private:
+    // All data members must be scalars
+    fmtflags        __fmtflags_;
+    streamsize      __precision_;
+    streamsize      __width_;
+    iostate         __rdstate_;
+    iostate         __exceptions_;
+    void*           __rdbuf_;
+    void*           __loc_;
+    event_callback* __fn_;
+    int*            __index_;
+    size_t          __event_size_;
+    size_t          __event_cap_;
+// TODO(EricWF): Enable this for both Clang and GCC. Currently it is only
+// enabled with clang.
+#if defined(_LIBCPP_HAS_C_ATOMIC_IMP) && !defined(_LIBCPP_HAS_NO_THREADS)
+    static atomic<int> __xindex_;
+#else
+    static int      __xindex_;
+#endif
+    long*           __iarray_;
+    size_t          __iarray_size_;
+    size_t          __iarray_cap_;
+    void**          __parray_;
+    size_t          __parray_size_;
+    size_t          __parray_cap_;
+};
+
+//enum class io_errc
+_LIBCPP_DECLARE_STRONG_ENUM(io_errc)
+{
+    stream = 1
+};
+_LIBCPP_DECLARE_STRONG_ENUM_EPILOG(io_errc)
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS is_error_code_enum<io_errc> : public true_type { };
+
+#ifdef _LIBCPP_HAS_NO_STRONG_ENUMS
+template <>
+struct _LIBCPP_TEMPLATE_VIS is_error_code_enum<io_errc::__lx> : public true_type { };
+#endif
+
+_LIBCPP_FUNC_VIS
+const error_category& iostream_category() _NOEXCEPT;
+
+inline _LIBCPP_INLINE_VISIBILITY
+error_code
+make_error_code(io_errc __e) _NOEXCEPT
+{
+    return error_code(static_cast<int>(__e), iostream_category());
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+error_condition
+make_error_condition(io_errc __e) _NOEXCEPT
+{
+    return error_condition(static_cast<int>(__e), iostream_category());
+}
+
+class _LIBCPP_EXCEPTION_ABI ios_base::failure
+    : public system_error
+{
+public:
+    explicit failure(const string& __msg, const error_code& __ec = io_errc::stream);
+    explicit failure(const char* __msg, const error_code& __ec = io_errc::stream);
+    failure(const failure&) _NOEXCEPT = default;
+    virtual ~failure() _NOEXCEPT;
+};
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+void __throw_failure(char const* __msg) {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw ios_base::failure(__msg);
+#else
+    ((void)__msg);
+    _VSTD::abort();
+#endif
+}
+
+class _LIBCPP_TYPE_VIS ios_base::Init
+{
+public:
+    Init();
+    ~Init();
+};
+
+// fmtflags
+
+inline _LIBCPP_INLINE_VISIBILITY
+ios_base::fmtflags
+ios_base::flags() const
+{
+    return __fmtflags_;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+ios_base::fmtflags
+ios_base::flags(fmtflags __fmtfl)
+{
+    fmtflags __r = __fmtflags_;
+    __fmtflags_ = __fmtfl;
+    return __r;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+ios_base::fmtflags
+ios_base::setf(fmtflags __fmtfl)
+{
+    fmtflags __r = __fmtflags_;
+    __fmtflags_ |= __fmtfl;
+    return __r;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+ios_base::unsetf(fmtflags __mask)
+{
+    __fmtflags_ &= ~__mask;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+ios_base::fmtflags
+ios_base::setf(fmtflags __fmtfl, fmtflags __mask)
+{
+    fmtflags __r = __fmtflags_;
+    unsetf(__mask);
+    __fmtflags_ |= __fmtfl & __mask;
+    return __r;
+}
+
+// precision
+
+inline _LIBCPP_INLINE_VISIBILITY
+streamsize
+ios_base::precision() const
+{
+    return __precision_;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+streamsize
+ios_base::precision(streamsize __prec)
+{
+    streamsize __r = __precision_;
+    __precision_ = __prec;
+    return __r;
+}
+
+// width
+
+inline _LIBCPP_INLINE_VISIBILITY
+streamsize
+ios_base::width() const
+{
+    return __width_;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+streamsize
+ios_base::width(streamsize __wide)
+{
+    streamsize __r = __width_;
+    __width_ = __wide;
+    return __r;
+}
+
+// iostate
+
+inline _LIBCPP_INLINE_VISIBILITY
+ios_base::iostate
+ios_base::rdstate() const
+{
+    return __rdstate_;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+ios_base::setstate(iostate __state)
+{
+    clear(__rdstate_ | __state);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+ios_base::good() const
+{
+    return __rdstate_ == 0;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+ios_base::eof() const
+{
+    return (__rdstate_ & eofbit) != 0;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+ios_base::fail() const
+{
+    return (__rdstate_ & (failbit | badbit)) != 0;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+ios_base::bad() const
+{
+    return (__rdstate_ & badbit) != 0;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+ios_base::iostate
+ios_base::exceptions() const
+{
+    return __exceptions_;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void
+ios_base::exceptions(iostate __iostate)
+{
+    __exceptions_ = __iostate;
+    clear(__rdstate_);
+}
+
+template <class _CharT, class _Traits>
+class _LIBCPP_TEMPLATE_VIS basic_ios
+    : public ios_base
+{
+public:
+    // types:
+    typedef _CharT char_type;
+    typedef _Traits traits_type;
+
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    static_assert((is_same<_CharT, typename traits_type::char_type>::value),
+                  "traits_type::char_type must be the same type as CharT");
+
+#ifdef _LIBCPP_CXX03_LANG
+    // Preserve the ability to compare with literal 0,
+    // and implicitly convert to bool, but not implicitly convert to int.
+    _LIBCPP_INLINE_VISIBILITY
+    operator void*() const {return fail() ? nullptr : (void*)this;}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit operator bool() const {return !fail();}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY bool operator!() const    {return  fail();}
+    _LIBCPP_INLINE_VISIBILITY iostate rdstate() const   {return ios_base::rdstate();}
+    _LIBCPP_INLINE_VISIBILITY void clear(iostate __state = goodbit) {ios_base::clear(__state);}
+    _LIBCPP_INLINE_VISIBILITY void setstate(iostate __state) {ios_base::setstate(__state);}
+    _LIBCPP_INLINE_VISIBILITY bool good() const {return ios_base::good();}
+    _LIBCPP_INLINE_VISIBILITY bool eof() const  {return ios_base::eof();}
+    _LIBCPP_INLINE_VISIBILITY bool fail() const {return ios_base::fail();}
+    _LIBCPP_INLINE_VISIBILITY bool bad() const  {return ios_base::bad();}
+
+    _LIBCPP_INLINE_VISIBILITY iostate exceptions() const {return ios_base::exceptions();}
+    _LIBCPP_INLINE_VISIBILITY void exceptions(iostate __iostate) {ios_base::exceptions(__iostate);}
+
+    // 27.5.4.1 Constructor/destructor:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_ios(basic_streambuf<char_type,traits_type>* __sb);
+    virtual ~basic_ios();
+
+    // 27.5.4.2 Members:
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ostream<char_type, traits_type>* tie() const;
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ostream<char_type, traits_type>* tie(basic_ostream<char_type, traits_type>* __tiestr);
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_streambuf<char_type, traits_type>* rdbuf() const;
+    _LIBCPP_INLINE_VISIBILITY
+    basic_streambuf<char_type, traits_type>* rdbuf(basic_streambuf<char_type, traits_type>* __sb);
+
+    basic_ios& copyfmt(const basic_ios& __rhs);
+
+    _LIBCPP_INLINE_VISIBILITY
+    char_type fill() const;
+    _LIBCPP_INLINE_VISIBILITY
+    char_type fill(char_type __ch);
+
+    _LIBCPP_INLINE_VISIBILITY
+    locale imbue(const locale& __loc);
+
+    _LIBCPP_INLINE_VISIBILITY
+    char narrow(char_type __c, char __dfault) const;
+    _LIBCPP_INLINE_VISIBILITY
+    char_type widen(char __c) const;
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ios() {// purposefully does no initialization
+                }
+    _LIBCPP_INLINE_VISIBILITY
+    void init(basic_streambuf<char_type, traits_type>* __sb);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void move(basic_ios& __rhs);
+    _LIBCPP_INLINE_VISIBILITY
+    void move(basic_ios&& __rhs) {move(__rhs);}
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(basic_ios& __rhs) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    void set_rdbuf(basic_streambuf<char_type, traits_type>* __sb);
+private:
+    basic_ostream<char_type, traits_type>* __tie_;
+    mutable int_type __fill_;
+};
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_ios<_CharT, _Traits>::basic_ios(basic_streambuf<char_type,traits_type>* __sb)
+{
+    init(__sb);
+}
+
+template <class _CharT, class _Traits>
+basic_ios<_CharT, _Traits>::~basic_ios()
+{
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+basic_ios<_CharT, _Traits>::init(basic_streambuf<char_type, traits_type>* __sb)
+{
+    ios_base::init(__sb);
+    __tie_ = nullptr;
+    __fill_ = traits_type::eof();
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_ostream<_CharT, _Traits>*
+basic_ios<_CharT, _Traits>::tie() const
+{
+    return __tie_;
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_ostream<_CharT, _Traits>*
+basic_ios<_CharT, _Traits>::tie(basic_ostream<char_type, traits_type>* __tiestr)
+{
+    basic_ostream<char_type, traits_type>* __r = __tie_;
+    __tie_ = __tiestr;
+    return __r;
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_streambuf<_CharT, _Traits>*
+basic_ios<_CharT, _Traits>::rdbuf() const
+{
+    return static_cast<basic_streambuf<char_type, traits_type>*>(ios_base::rdbuf());
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_streambuf<_CharT, _Traits>*
+basic_ios<_CharT, _Traits>::rdbuf(basic_streambuf<char_type, traits_type>* __sb)
+{
+    basic_streambuf<char_type, traits_type>* __r = rdbuf();
+    ios_base::rdbuf(__sb);
+    return __r;
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+locale
+basic_ios<_CharT, _Traits>::imbue(const locale& __loc)
+{
+    locale __r = getloc();
+    ios_base::imbue(__loc);
+    if (rdbuf())
+        rdbuf()->pubimbue(__loc);
+    return __r;
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+char
+basic_ios<_CharT, _Traits>::narrow(char_type __c, char __dfault) const
+{
+    return use_facet<ctype<char_type> >(getloc()).narrow(__c, __dfault);
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+_CharT
+basic_ios<_CharT, _Traits>::widen(char __c) const
+{
+    return use_facet<ctype<char_type> >(getloc()).widen(__c);
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+_CharT
+basic_ios<_CharT, _Traits>::fill() const
+{
+    if (traits_type::eq_int_type(traits_type::eof(), __fill_))
+        __fill_ = widen(' ');
+    return __fill_;
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+_CharT
+basic_ios<_CharT, _Traits>::fill(char_type __ch)
+{
+    char_type __r = __fill_;
+    __fill_ = __ch;
+    return __r;
+}
+
+template <class _CharT, class _Traits>
+basic_ios<_CharT, _Traits>&
+basic_ios<_CharT, _Traits>::copyfmt(const basic_ios& __rhs)
+{
+    if (this != &__rhs)
+    {
+        __call_callbacks(erase_event);
+        ios_base::copyfmt(__rhs);
+        __tie_ = __rhs.__tie_;
+        __fill_ = __rhs.__fill_;
+        __call_callbacks(copyfmt_event);
+        exceptions(__rhs.exceptions());
+    }
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+basic_ios<_CharT, _Traits>::move(basic_ios& __rhs)
+{
+    ios_base::move(__rhs);
+    __tie_ = __rhs.__tie_;
+    __rhs.__tie_ = nullptr;
+    __fill_ = __rhs.__fill_;
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+basic_ios<_CharT, _Traits>::swap(basic_ios& __rhs) _NOEXCEPT
+{
+    ios_base::swap(__rhs);
+    _VSTD::swap(__tie_, __rhs.__tie_);
+    _VSTD::swap(__fill_, __rhs.__fill_);
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+basic_ios<_CharT, _Traits>::set_rdbuf(basic_streambuf<char_type, traits_type>* __sb)
+{
+    ios_base::set_rdbuf(__sb);
+}
+
+inline
+ios_base&
+boolalpha(ios_base& __str)
+{
+    __str.setf(ios_base::boolalpha);
+    return __str;
+}
+
+inline
+ios_base&
+noboolalpha(ios_base& __str)
+{
+    __str.unsetf(ios_base::boolalpha);
+    return __str;
+}
+
+inline
+ios_base&
+showbase(ios_base& __str)
+{
+    __str.setf(ios_base::showbase);
+    return __str;
+}
+
+inline
+ios_base&
+noshowbase(ios_base& __str)
+{
+    __str.unsetf(ios_base::showbase);
+    return __str;
+}
+
+inline
+ios_base&
+showpoint(ios_base& __str)
+{
+    __str.setf(ios_base::showpoint);
+    return __str;
+}
+
+inline
+ios_base&
+noshowpoint(ios_base& __str)
+{
+    __str.unsetf(ios_base::showpoint);
+    return __str;
+}
+
+inline
+ios_base&
+showpos(ios_base& __str)
+{
+    __str.setf(ios_base::showpos);
+    return __str;
+}
+
+inline
+ios_base&
+noshowpos(ios_base& __str)
+{
+    __str.unsetf(ios_base::showpos);
+    return __str;
+}
+
+inline
+ios_base&
+skipws(ios_base& __str)
+{
+    __str.setf(ios_base::skipws);
+    return __str;
+}
+
+inline
+ios_base&
+noskipws(ios_base& __str)
+{
+    __str.unsetf(ios_base::skipws);
+    return __str;
+}
+
+inline
+ios_base&
+uppercase(ios_base& __str)
+{
+    __str.setf(ios_base::uppercase);
+    return __str;
+}
+
+inline
+ios_base&
+nouppercase(ios_base& __str)
+{
+    __str.unsetf(ios_base::uppercase);
+    return __str;
+}
+
+inline
+ios_base&
+unitbuf(ios_base& __str)
+{
+    __str.setf(ios_base::unitbuf);
+    return __str;
+}
+
+inline
+ios_base&
+nounitbuf(ios_base& __str)
+{
+    __str.unsetf(ios_base::unitbuf);
+    return __str;
+}
+
+inline
+ios_base&
+internal(ios_base& __str)
+{
+    __str.setf(ios_base::internal, ios_base::adjustfield);
+    return __str;
+}
+
+inline
+ios_base&
+left(ios_base& __str)
+{
+    __str.setf(ios_base::left, ios_base::adjustfield);
+    return __str;
+}
+
+inline
+ios_base&
+right(ios_base& __str)
+{
+    __str.setf(ios_base::right, ios_base::adjustfield);
+    return __str;
+}
+
+inline
+ios_base&
+dec(ios_base& __str)
+{
+    __str.setf(ios_base::dec, ios_base::basefield);
+    return __str;
+}
+
+inline
+ios_base&
+hex(ios_base& __str)
+{
+    __str.setf(ios_base::hex, ios_base::basefield);
+    return __str;
+}
+
+inline
+ios_base&
+oct(ios_base& __str)
+{
+    __str.setf(ios_base::oct, ios_base::basefield);
+    return __str;
+}
+
+inline
+ios_base&
+fixed(ios_base& __str)
+{
+    __str.setf(ios_base::fixed, ios_base::floatfield);
+    return __str;
+}
+
+inline
+ios_base&
+scientific(ios_base& __str)
+{
+    __str.setf(ios_base::scientific, ios_base::floatfield);
+    return __str;
+}
+
+inline
+ios_base&
+hexfloat(ios_base& __str)
+{
+    __str.setf(ios_base::fixed | ios_base::scientific, ios_base::floatfield);
+    return __str;
+}
+
+inline
+ios_base&
+defaultfloat(ios_base& __str)
+{
+    __str.unsetf(ios_base::floatfield);
+    return __str;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_IOS
diff --git a/contrib/libs/cxxsupp/libcxx/include/iosfwd b/contrib/libs/cxxsupp/libcxx/include/iosfwd
new file mode 100644
index 00000000000..477dd97260f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/iosfwd
@@ -0,0 +1,291 @@
+// -*- C++ -*-
+//===--------------------------- iosfwd -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_IOSFWD
+#define _LIBCPP_IOSFWD
+
+/*
+    iosfwd synopsis
+
+namespace std
+{
+
+template<class charT> struct char_traits;
+template<>            struct char_traits<char>;
+template<>            struct char_traits<char8_t>;  // C++20
+template<>            struct char_traits<char16_t>;
+template<>            struct char_traits<char32_t>;
+template<>            struct char_traits<wchar_t>;
+
+template<class T>     class allocator;
+
+class ios_base;
+template <class charT, class traits = char_traits<charT> > class basic_ios;
+
+template <class charT, class traits = char_traits<charT> > class basic_streambuf;
+template <class charT, class traits = char_traits<charT> > class basic_istream;
+template <class charT, class traits = char_traits<charT> > class basic_ostream;
+template <class charT, class traits = char_traits<charT> > class basic_iostream;
+
+template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+    class basic_stringbuf;
+template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+    class basic_istringstream;
+template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+    class basic_ostringstream;
+template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+    class basic_stringstream;
+
+template <class charT, class traits = char_traits<charT> > class basic_filebuf;
+template <class charT, class traits = char_traits<charT> > class basic_ifstream;
+template <class charT, class traits = char_traits<charT> > class basic_ofstream;
+template <class charT, class traits = char_traits<charT> > class basic_fstream;
+
+template <class charT, class traits = char_traits<charT> > class istreambuf_iterator;
+template <class charT, class traits = char_traits<charT> > class ostreambuf_iterator;
+
+typedef basic_ios<char>              ios;
+typedef basic_ios<wchar_t>           wios;
+
+typedef basic_streambuf<char>        streambuf;
+typedef basic_istream<char>          istream;
+typedef basic_ostream<char>          ostream;
+typedef basic_iostream<char>         iostream;
+
+typedef basic_stringbuf<char>        stringbuf;
+typedef basic_istringstream<char>    istringstream;
+typedef basic_ostringstream<char>    ostringstream;
+typedef basic_stringstream<char>     stringstream;
+
+typedef basic_filebuf<char>          filebuf;
+typedef basic_ifstream<char>         ifstream;
+typedef basic_ofstream<char>         ofstream;
+typedef basic_fstream<char>          fstream;
+
+typedef basic_streambuf<wchar_t>     wstreambuf;
+typedef basic_istream<wchar_t>       wistream;
+typedef basic_ostream<wchar_t>       wostream;
+typedef basic_iostream<wchar_t>      wiostream;
+
+typedef basic_stringbuf<wchar_t>     wstringbuf;
+typedef basic_istringstream<wchar_t> wistringstream;
+typedef basic_ostringstream<wchar_t> wostringstream;
+typedef basic_stringstream<wchar_t>  wstringstream;
+
+typedef basic_filebuf<wchar_t>       wfilebuf;
+typedef basic_ifstream<wchar_t>      wifstream;
+typedef basic_ofstream<wchar_t>      wofstream;
+typedef basic_fstream<wchar_t>       wfstream;
+
+template <class state> class fpos;
+using streampos  = fpos<char_traits<char>::state_type>;
+using wstreampos = fpos<char_traits<wchar_t>::state_type>;
+using u8streampos = fpos<char_traits<char8_t>::state_type>; // C++20
+using u16streampos = fpos<char_traits<char16_t>::state_type>;
+using u32streampos = fpos<char_traits<char32_t>::state_type>;
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__mbstate_t.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+class _LIBCPP_TYPE_VIS ios_base;
+
+template<class _CharT>  struct _LIBCPP_TEMPLATE_VIS char_traits;
+template<> struct char_traits<char>;
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+template<> struct char_traits<char8_t>;
+#endif
+template<> struct char_traits<char16_t>;
+template<> struct char_traits<char32_t>;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template<> struct char_traits<wchar_t>;
+#endif
+
+template<class _Tp>     class _LIBCPP_TEMPLATE_VIS allocator;
+
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_ios;
+
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_streambuf;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_istream;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_ostream;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_iostream;
+
+template <class _CharT, class _Traits = char_traits<_CharT>,
+          class _Allocator = allocator<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_stringbuf;
+template <class _CharT, class _Traits = char_traits<_CharT>,
+          class _Allocator = allocator<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_istringstream;
+template <class _CharT, class _Traits = char_traits<_CharT>,
+          class _Allocator = allocator<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_ostringstream;
+template <class _CharT, class _Traits = char_traits<_CharT>,
+          class _Allocator = allocator<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_stringstream;
+
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_filebuf;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_ifstream;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_ofstream;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_fstream;
+
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS istreambuf_iterator;
+template <class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS ostreambuf_iterator;
+
+typedef basic_ios<char>              ios;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef basic_ios<wchar_t>           wios;
+#endif
+
+typedef basic_streambuf<char>        streambuf;
+typedef basic_istream<char>          istream;
+typedef basic_ostream<char>          ostream;
+typedef basic_iostream<char>         iostream;
+
+typedef basic_stringbuf<char>        stringbuf;
+typedef basic_istringstream<char>    istringstream;
+typedef basic_ostringstream<char>    ostringstream;
+typedef basic_stringstream<char>     stringstream;
+
+typedef basic_filebuf<char>          filebuf;
+typedef basic_ifstream<char>         ifstream;
+typedef basic_ofstream<char>         ofstream;
+typedef basic_fstream<char>          fstream;
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef basic_streambuf<wchar_t>     wstreambuf;
+typedef basic_istream<wchar_t>       wistream;
+typedef basic_ostream<wchar_t>       wostream;
+typedef basic_iostream<wchar_t>      wiostream;
+
+typedef basic_stringbuf<wchar_t>     wstringbuf;
+typedef basic_istringstream<wchar_t> wistringstream;
+typedef basic_ostringstream<wchar_t> wostringstream;
+typedef basic_stringstream<wchar_t>  wstringstream;
+
+typedef basic_filebuf<wchar_t>       wfilebuf;
+typedef basic_ifstream<wchar_t>      wifstream;
+typedef basic_ofstream<wchar_t>      wofstream;
+typedef basic_fstream<wchar_t>       wfstream;
+#endif
+
+template <class _CharT, class _Traits>
+    class _LIBCPP_PREFERRED_NAME(ios) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wios)) basic_ios;
+
+template <class _CharT, class _Traits>
+    class _LIBCPP_PREFERRED_NAME(streambuf) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wstreambuf)) basic_streambuf;
+template <class _CharT, class _Traits>
+    class _LIBCPP_PREFERRED_NAME(istream) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wistream)) basic_istream;
+template <class _CharT, class _Traits>
+    class _LIBCPP_PREFERRED_NAME(ostream) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wostream)) basic_ostream;
+template <class _CharT, class _Traits>
+    class _LIBCPP_PREFERRED_NAME(iostream) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wiostream)) basic_iostream;
+
+template <class _CharT, class _Traits, class _Allocator>
+    class _LIBCPP_PREFERRED_NAME(stringbuf) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wstringbuf)) basic_stringbuf;
+template <class _CharT, class _Traits, class _Allocator>
+    class _LIBCPP_PREFERRED_NAME(istringstream) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wistringstream)) basic_istringstream;
+template <class _CharT, class _Traits, class _Allocator>
+    class _LIBCPP_PREFERRED_NAME(ostringstream) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wostringstream)) basic_ostringstream;
+template <class _CharT, class _Traits, class _Allocator>
+    class _LIBCPP_PREFERRED_NAME(stringstream) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wstringstream)) basic_stringstream;
+
+template <class _CharT, class _Traits>
+    class _LIBCPP_PREFERRED_NAME(filebuf) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wfilebuf)) basic_filebuf;
+template <class _CharT, class _Traits>
+    class _LIBCPP_PREFERRED_NAME(ifstream) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wifstream)) basic_ifstream;
+template <class _CharT, class _Traits>
+    class _LIBCPP_PREFERRED_NAME(ofstream) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wofstream)) basic_ofstream;
+template <class _CharT, class _Traits>
+    class _LIBCPP_PREFERRED_NAME(fstream) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wfstream)) basic_fstream;
+
+template <class _State>             class _LIBCPP_TEMPLATE_VIS fpos;
+typedef fpos<mbstate_t>    streampos;
+typedef fpos<mbstate_t>    wstreampos;
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+typedef fpos<mbstate_t>    u8streampos;
+#endif
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+typedef fpos<mbstate_t>    u16streampos;
+typedef fpos<mbstate_t>    u32streampos;
+#endif
+
+#if defined(_NEWLIB_VERSION)
+// On newlib, off_t is 'long int'
+typedef long int streamoff;         // for char_traits in <string>
+#else
+typedef long long streamoff;        // for char_traits in <string>
+#endif
+
+template <class _CharT,             // for <stdexcept>
+          class _Traits = char_traits<_CharT>,
+          class _Allocator = allocator<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_string;
+typedef basic_string<char, char_traits<char>, allocator<char> > string;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef basic_string<wchar_t, char_traits<wchar_t>, allocator<wchar_t> > wstring;
+#endif
+typedef basic_string<char16_t, char_traits<char16_t>, allocator<char16_t> > u16string;
+
+template <class _CharT, class _Traits, class _Allocator>
+    class _LIBCPP_PREFERRED_NAME(string) _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wstring)) basic_string;
+
+// Include other forward declarations here
+template <class _Tp, class _Alloc = allocator<_Tp> >
+class _LIBCPP_TEMPLATE_VIS vector;
+
+template <class _CharT, class _Traits>
+class __save_flags
+{
+    typedef basic_ios<_CharT, _Traits> __stream_type;
+    typedef typename __stream_type::fmtflags fmtflags;
+
+    __stream_type& __stream_;
+    fmtflags       __fmtflags_;
+    _CharT         __fill_;
+
+    __save_flags(const __save_flags&);
+    __save_flags& operator=(const __save_flags&);
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __save_flags(__stream_type& __stream)
+        : __stream_(__stream),
+          __fmtflags_(__stream.flags()),
+          __fill_(__stream.fill())
+        {}
+    _LIBCPP_INLINE_VISIBILITY
+    ~__save_flags()
+    {
+        __stream_.flags(__fmtflags_);
+        __stream_.fill(__fill_);
+    }
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_IOSFWD
diff --git a/contrib/libs/cxxsupp/libcxx/include/iostream b/contrib/libs/cxxsupp/libcxx/include/iostream
new file mode 100644
index 00000000000..be32183e3a8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/iostream
@@ -0,0 +1,88 @@
+// -*- C++ -*-
+//===--------------------------- iostream ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_IOSTREAM
+#define _LIBCPP_IOSTREAM
+
+/*
+    iostream synopsis
+
+#include <ios>
+#include <istream>
+#include <ostream>
+#include <streambuf>
+
+namespace std {
+
+extern istream cin;
+extern ostream cout;
+extern ostream cerr;
+extern ostream clog;
+extern wistream wcin;
+extern wostream wcout;
+extern wostream wcerr;
+extern wostream wclog;
+
+}  // std
+
+*/
+
+#include <__config>
+#include <ios>
+#include <istream>
+#include <ostream>
+#include <streambuf>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if defined(_MSC_VER) && !defined(__clang__)
+extern _LIBCPP_FUNC_VIS istream& cin;
+#else
+extern _LIBCPP_FUNC_VIS istream cin;
+#endif
+#if defined(_MSC_VER) && !defined(__clang__)
+extern _LIBCPP_FUNC_VIS ostream& cout;
+#else
+extern _LIBCPP_FUNC_VIS ostream cout;
+#endif
+#if defined(_MSC_VER) && !defined(__clang__)
+extern _LIBCPP_FUNC_VIS ostream& cerr;
+extern _LIBCPP_FUNC_VIS ostream& clog;
+#else
+extern _LIBCPP_FUNC_VIS ostream cerr;
+extern _LIBCPP_FUNC_VIS ostream clog;
+#endif
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#if defined(_MSC_VER) && !defined(__clang__)
+extern _LIBCPP_FUNC_VIS wistream& wcin;
+#else
+extern _LIBCPP_FUNC_VIS wistream wcin;
+#endif
+#if defined(_MSC_VER) && !defined(__clang__)
+extern _LIBCPP_FUNC_VIS wostream& wcout;
+#else
+extern _LIBCPP_FUNC_VIS wostream wcout;
+#endif
+#if defined(_MSC_VER) && !defined(__clang__)
+extern _LIBCPP_FUNC_VIS wostream& wcerr;
+extern _LIBCPP_FUNC_VIS wostream& wclog;
+#else
+extern _LIBCPP_FUNC_VIS wostream wcerr;
+extern _LIBCPP_FUNC_VIS wostream wclog;
+#endif
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_IOSTREAM
diff --git a/contrib/libs/cxxsupp/libcxx/include/istream b/contrib/libs/cxxsupp/libcxx/include/istream
new file mode 100644
index 00000000000..6fb296f820f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/istream
@@ -0,0 +1,1640 @@
+// -*- C++ -*-
+//===--------------------------- istream ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_ISTREAM
+#define _LIBCPP_ISTREAM
+
+/*
+    istream synopsis
+
+template <class charT, class traits = char_traits<charT> >
+class basic_istream
+    : virtual public basic_ios<charT,traits>
+{
+public:
+    // types (inherited from basic_ios (27.5.4)):
+    typedef charT                          char_type;
+    typedef traits                         traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    // 27.7.1.1.1 Constructor/destructor:
+    explicit basic_istream(basic_streambuf<char_type, traits_type>* sb);
+    basic_istream(basic_istream&& rhs);
+    virtual ~basic_istream();
+
+    // 27.7.1.1.2 Assign/swap:
+    basic_istream& operator=(basic_istream&& rhs);
+    void swap(basic_istream& rhs);
+
+    // 27.7.1.1.3 Prefix/suffix:
+    class sentry;
+
+    // 27.7.1.2 Formatted input:
+    basic_istream& operator>>(basic_istream& (*pf)(basic_istream&));
+    basic_istream& operator>>(basic_ios<char_type, traits_type>&
+                              (*pf)(basic_ios<char_type, traits_type>&));
+    basic_istream& operator>>(ios_base& (*pf)(ios_base&));
+    basic_istream& operator>>(basic_streambuf<char_type, traits_type>* sb);
+    basic_istream& operator>>(bool& n);
+    basic_istream& operator>>(short& n);
+    basic_istream& operator>>(unsigned short& n);
+    basic_istream& operator>>(int& n);
+    basic_istream& operator>>(unsigned int& n);
+    basic_istream& operator>>(long& n);
+    basic_istream& operator>>(unsigned long& n);
+    basic_istream& operator>>(long long& n);
+    basic_istream& operator>>(unsigned long long& n);
+    basic_istream& operator>>(float& f);
+    basic_istream& operator>>(double& f);
+    basic_istream& operator>>(long double& f);
+    basic_istream& operator>>(void*& p);
+
+    // 27.7.1.3 Unformatted input:
+    streamsize gcount() const;
+    int_type get();
+    basic_istream& get(char_type& c);
+    basic_istream& get(char_type* s, streamsize n);
+    basic_istream& get(char_type* s, streamsize n, char_type delim);
+    basic_istream& get(basic_streambuf<char_type,traits_type>& sb);
+    basic_istream& get(basic_streambuf<char_type,traits_type>& sb, char_type delim);
+
+    basic_istream& getline(char_type* s, streamsize n);
+    basic_istream& getline(char_type* s, streamsize n, char_type delim);
+
+    basic_istream& ignore(streamsize n = 1, int_type delim = traits_type::eof());
+    int_type peek();
+    basic_istream& read (char_type* s, streamsize n);
+    streamsize readsome(char_type* s, streamsize n);
+
+    basic_istream& putback(char_type c);
+    basic_istream& unget();
+    int sync();
+
+    pos_type tellg();
+    basic_istream& seekg(pos_type);
+    basic_istream& seekg(off_type, ios_base::seekdir);
+protected:
+    basic_istream(const basic_istream& rhs) = delete;
+    basic_istream(basic_istream&& rhs);
+    // 27.7.2.1.2 Assign/swap:
+    basic_istream& operator=(const basic_istream& rhs) = delete;
+    basic_istream& operator=(basic_istream&& rhs);
+    void swap(basic_istream& rhs);
+};
+
+// 27.7.1.2.3 character extraction templates:
+template<class charT, class traits>
+  basic_istream<charT,traits>& operator>>(basic_istream<charT,traits>&, charT&);
+
+template<class traits>
+  basic_istream<char,traits>& operator>>(basic_istream<char,traits>&, unsigned char&);
+
+template<class traits>
+  basic_istream<char,traits>& operator>>(basic_istream<char,traits>&, signed char&);
+
+template<class charT, class traits>
+  basic_istream<charT,traits>& operator>>(basic_istream<charT,traits>&, charT*);
+
+template<class traits>
+  basic_istream<char,traits>& operator>>(basic_istream<char,traits>&, unsigned char*);
+
+template<class traits>
+  basic_istream<char,traits>& operator>>(basic_istream<char,traits>&, signed char*);
+
+template <class charT, class traits>
+  void
+  swap(basic_istream<charT, traits>& x, basic_istream<charT, traits>& y);
+
+typedef basic_istream<char> istream;
+typedef basic_istream<wchar_t> wistream;
+
+template <class charT, class traits = char_traits<charT> >
+class basic_iostream :
+    public basic_istream<charT,traits>,
+    public basic_ostream<charT,traits>
+{
+public:
+    // types:
+    typedef charT                          char_type;
+    typedef traits                         traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    // constructor/destructor
+    explicit basic_iostream(basic_streambuf<char_type, traits_type>* sb);
+    basic_iostream(basic_iostream&& rhs);
+    virtual ~basic_iostream();
+
+    // assign/swap
+    basic_iostream& operator=(basic_iostream&& rhs);
+    void swap(basic_iostream& rhs);
+};
+
+template <class charT, class traits>
+  void
+  swap(basic_iostream<charT, traits>& x, basic_iostream<charT, traits>& y);
+
+typedef basic_iostream<char> iostream;
+typedef basic_iostream<wchar_t> wiostream;
+
+template <class charT, class traits>
+  basic_istream<charT,traits>&
+  ws(basic_istream<charT,traits>& is);
+
+// rvalue stream extraction
+template <class Stream, class T>
+  Stream&& operator>>(Stream&& is, T&& x);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__utility/forward.h>
+#include <ostream>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _CharT, class _Traits>
+class _LIBCPP_TEMPLATE_VIS basic_istream
+    : virtual public basic_ios<_CharT, _Traits>
+{
+    streamsize __gc_;
+public:
+    // types (inherited from basic_ios (27.5.4)):
+    typedef _CharT                         char_type;
+    typedef _Traits                        traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    // 27.7.1.1.1 Constructor/destructor:
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    explicit basic_istream(basic_streambuf<char_type, traits_type>* __sb) : __gc_(0)
+    { this->init(__sb); }
+    virtual ~basic_istream();
+protected:
+    inline _LIBCPP_INLINE_VISIBILITY
+    basic_istream(basic_istream&& __rhs);
+
+    // 27.7.1.1.2 Assign/swap:
+    inline _LIBCPP_INLINE_VISIBILITY
+    basic_istream& operator=(basic_istream&& __rhs);
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    void swap(basic_istream& __rhs) {
+      _VSTD::swap(__gc_, __rhs.__gc_);
+      basic_ios<char_type, traits_type>::swap(__rhs);
+    }
+
+    basic_istream           (const basic_istream& __rhs) = delete;
+    basic_istream& operator=(const basic_istream& __rhs) = delete;
+public:
+
+    // 27.7.1.1.3 Prefix/suffix:
+    class _LIBCPP_TEMPLATE_VIS sentry;
+
+    // 27.7.1.2 Formatted input:
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    basic_istream& operator>>(basic_istream& (*__pf)(basic_istream&))
+    { return __pf(*this); }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    basic_istream& operator>>(basic_ios<char_type, traits_type>&
+                              (*__pf)(basic_ios<char_type, traits_type>&))
+    { __pf(*this); return *this; }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    basic_istream& operator>>(ios_base& (*__pf)(ios_base&))
+    { __pf(*this); return *this; }
+
+    basic_istream& operator>>(basic_streambuf<char_type, traits_type>* __sb);
+    basic_istream& operator>>(bool& __n);
+    basic_istream& operator>>(short& __n);
+    basic_istream& operator>>(unsigned short& __n);
+    basic_istream& operator>>(int& __n);
+    basic_istream& operator>>(unsigned int& __n);
+    basic_istream& operator>>(long& __n);
+    basic_istream& operator>>(unsigned long& __n);
+    basic_istream& operator>>(long long& __n);
+    basic_istream& operator>>(unsigned long long& __n);
+    basic_istream& operator>>(float& __f);
+    basic_istream& operator>>(double& __f);
+    basic_istream& operator>>(long double& __f);
+    basic_istream& operator>>(void*& __p);
+
+    // 27.7.1.3 Unformatted input:
+    _LIBCPP_INLINE_VISIBILITY
+    streamsize gcount() const {return __gc_;}
+    int_type get();
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    basic_istream& get(char_type& __c) {
+      int_type __ch = get();
+      if (__ch != traits_type::eof())
+        __c = traits_type::to_char_type(__ch);
+      return *this;
+    }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    basic_istream& get(char_type* __s, streamsize __n)
+    { return get(__s, __n, this->widen('\n')); }
+
+    basic_istream& get(char_type* __s, streamsize __n, char_type __dlm);
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    basic_istream& get(basic_streambuf<char_type, traits_type>& __sb)
+    { return get(__sb, this->widen('\n')); }
+
+    basic_istream& get(basic_streambuf<char_type, traits_type>& __sb, char_type __dlm);
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    basic_istream& getline(char_type* __s, streamsize __n)
+    { return getline(__s, __n, this->widen('\n')); }
+
+    basic_istream& getline(char_type* __s, streamsize __n, char_type __dlm);
+
+    basic_istream& ignore(streamsize __n = 1, int_type __dlm = traits_type::eof());
+    int_type peek();
+    basic_istream& read (char_type* __s, streamsize __n);
+    streamsize readsome(char_type* __s, streamsize __n);
+
+    basic_istream& putback(char_type __c);
+    basic_istream& unget();
+    int sync();
+
+    pos_type tellg();
+    basic_istream& seekg(pos_type __pos);
+    basic_istream& seekg(off_type __off, ios_base::seekdir __dir);
+};
+
+template <class _CharT, class _Traits>
+class _LIBCPP_TEMPLATE_VIS basic_istream<_CharT, _Traits>::sentry
+{
+    bool __ok_;
+
+    sentry(const sentry&); // = delete;
+    sentry& operator=(const sentry&); // = delete;
+
+public:
+    explicit sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false);
+//    ~sentry() = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit operator bool() const {return __ok_;}
+};
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>::sentry::sentry(basic_istream<_CharT, _Traits>& __is,
+                                               bool __noskipws)
+    : __ok_(false)
+{
+    if (__is.good())
+    {
+        if (__is.tie())
+            __is.tie()->flush();
+        if (!__noskipws && (__is.flags() & ios_base::skipws))
+        {
+            typedef istreambuf_iterator<_CharT, _Traits> _Ip;
+            const ctype<_CharT>& __ct = use_facet<ctype<_CharT> >(__is.getloc());
+            _Ip __i(__is);
+            _Ip __eof;
+            for (; __i != __eof; ++__i)
+                if (!__ct.is(__ct.space, *__i))
+                    break;
+            if (__i == __eof)
+                __is.setstate(ios_base::failbit | ios_base::eofbit);
+        }
+        __ok_ = __is.good();
+    }
+    else
+        __is.setstate(ios_base::failbit);
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>::basic_istream(basic_istream&& __rhs)
+    : __gc_(__rhs.__gc_)
+{
+    __rhs.__gc_ = 0;
+    this->move(__rhs);
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator=(basic_istream&& __rhs)
+{
+    swap(__rhs);
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>::~basic_istream()
+{
+}
+
+template <class _Tp, class _CharT, class _Traits>
+_LIBCPP_INLINE_VISIBILITY
+basic_istream<_CharT, _Traits>&
+__input_arithmetic(basic_istream<_CharT, _Traits>& __is, _Tp& __n) {
+    ios_base::iostate __state = ios_base::goodbit;
+    typename basic_istream<_CharT, _Traits>::sentry __s(__is);
+    if (__s)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            typedef istreambuf_iterator<_CharT, _Traits> _Ip;
+            typedef num_get<_CharT, _Ip> _Fp;
+            use_facet<_Fp>(__is.getloc()).get(_Ip(__is), _Ip(), __is, __state, __n);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            __is.__setstate_nothrow(__state);
+            if (__is.exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif
+        __is.setstate(__state);
+    }
+    return __is;
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(unsigned short& __n)
+{
+    return _VSTD::__input_arithmetic<unsigned short>(*this, __n);
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(unsigned int& __n)
+{
+    return _VSTD::__input_arithmetic<unsigned int>(*this, __n);
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(long& __n)
+{
+    return _VSTD::__input_arithmetic<long>(*this, __n);
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(unsigned long& __n)
+{
+    return _VSTD::__input_arithmetic<unsigned long>(*this, __n);
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(long long& __n)
+{
+    return _VSTD::__input_arithmetic<long long>(*this, __n);
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(unsigned long long& __n)
+{
+    return _VSTD::__input_arithmetic<unsigned long long>(*this, __n);
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(float& __n)
+{
+    return _VSTD::__input_arithmetic<float>(*this, __n);
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(double& __n)
+{
+    return _VSTD::__input_arithmetic<double>(*this, __n);
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(long double& __n)
+{
+    return _VSTD::__input_arithmetic<long double>(*this, __n);
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(bool& __n)
+{
+    return _VSTD::__input_arithmetic<bool>(*this, __n);
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(void*& __n)
+{
+    return _VSTD::__input_arithmetic<void*>(*this, __n);
+}
+
+template <class _Tp, class _CharT, class _Traits>
+_LIBCPP_INLINE_VISIBILITY
+basic_istream<_CharT, _Traits>&
+__input_arithmetic_with_numeric_limits(basic_istream<_CharT, _Traits>& __is, _Tp& __n) {
+    ios_base::iostate __state = ios_base::goodbit;
+    typename basic_istream<_CharT, _Traits>::sentry __s(__is);
+    if (__s)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            typedef istreambuf_iterator<_CharT, _Traits> _Ip;
+            typedef num_get<_CharT, _Ip> _Fp;
+            long __temp;
+            use_facet<_Fp>(__is.getloc()).get(_Ip(__is), _Ip(), __is, __state, __temp);
+            if (__temp < numeric_limits<_Tp>::min())
+            {
+                __state |= ios_base::failbit;
+                __n = numeric_limits<_Tp>::min();
+            }
+            else if (__temp > numeric_limits<_Tp>::max())
+            {
+                __state |= ios_base::failbit;
+                __n = numeric_limits<_Tp>::max();
+            }
+            else
+            {
+                __n = static_cast<_Tp>(__temp);
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            __is.__setstate_nothrow(__state);
+            if (__is.exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __is.setstate(__state);
+    }
+    return __is;
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(short& __n)
+{
+    return _VSTD::__input_arithmetic_with_numeric_limits<short>(*this, __n);
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(int& __n)
+{
+    return _VSTD::__input_arithmetic_with_numeric_limits<int>(*this, __n);
+}
+
+template<class _CharT, class _Traits>
+_LIBCPP_INLINE_VISIBILITY
+basic_istream<_CharT, _Traits>&
+__input_c_string(basic_istream<_CharT, _Traits>& __is, _CharT* __p, size_t __n)
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    typename basic_istream<_CharT, _Traits>::sentry __sen(__is);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif
+            _CharT* __s = __p;
+            const ctype<_CharT>& __ct = use_facet<ctype<_CharT> >(__is.getloc());
+            while (__s != __p + (__n-1))
+            {
+                typename _Traits::int_type __i = __is.rdbuf()->sgetc();
+                if (_Traits::eq_int_type(__i, _Traits::eof()))
+                {
+                   __state |= ios_base::eofbit;
+                   break;
+                }
+                _CharT __ch = _Traits::to_char_type(__i);
+                if (__ct.is(__ct.space, __ch))
+                    break;
+                *__s++ = __ch;
+                 __is.rdbuf()->sbumpc();
+            }
+            *__s = _CharT();
+            __is.width(0);
+            if (__s == __p)
+               __state |= ios_base::failbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            __is.__setstate_nothrow(__state);
+            if (__is.exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif
+        __is.setstate(__state);
+    }
+    return __is;
+}
+
+#if _LIBCPP_STD_VER > 17
+
+template<class _CharT, class _Traits, size_t _Np>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, _CharT (&__buf)[_Np])
+{
+    size_t __n = _Np;
+    if (__is.width() > 0)
+        __n = _VSTD::min(size_t(__is.width()), _Np);
+    return _VSTD::__input_c_string(__is, __buf, __n);
+}
+
+template<class _Traits, size_t _Np>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<char, _Traits>&
+operator>>(basic_istream<char, _Traits>& __is, unsigned char (&__buf)[_Np])
+{
+    return __is >> (char(&)[_Np])__buf;
+}
+
+template<class _Traits, size_t _Np>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<char, _Traits>&
+operator>>(basic_istream<char, _Traits>& __is, signed char (&__buf)[_Np])
+{
+    return __is >> (char(&)[_Np])__buf;
+}
+
+#else
+
+template<class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, _CharT* __s)
+{
+    streamsize __n = __is.width();
+    if (__n <= 0)
+        __n = numeric_limits<streamsize>::max() / sizeof(_CharT) - 1;
+    return _VSTD::__input_c_string(__is, __s, size_t(__n));
+}
+
+template<class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<char, _Traits>&
+operator>>(basic_istream<char, _Traits>& __is, unsigned char* __s)
+{
+    return __is >> (char*)__s;
+}
+
+template<class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<char, _Traits>&
+operator>>(basic_istream<char, _Traits>& __is, signed char* __s)
+{
+    return __is >> (char*)__s;
+}
+
+#endif // _LIBCPP_STD_VER > 17
+
+template<class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, _CharT& __c)
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    typename basic_istream<_CharT, _Traits>::sentry __sen(__is);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif
+            typename _Traits::int_type __i = __is.rdbuf()->sbumpc();
+            if (_Traits::eq_int_type(__i, _Traits::eof()))
+                __state |= ios_base::eofbit | ios_base::failbit;
+            else
+                __c = _Traits::to_char_type(__i);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            __is.__setstate_nothrow(__state);
+            if (__is.exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif
+        __is.setstate(__state);
+    }
+    return __is;
+}
+
+template<class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<char, _Traits>&
+operator>>(basic_istream<char, _Traits>& __is, unsigned char& __c)
+{
+    return __is >> (char&)__c;
+}
+
+template<class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<char, _Traits>&
+operator>>(basic_istream<char, _Traits>& __is, signed char& __c)
+{
+    return __is >> (char&)__c;
+}
+
+template<class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::operator>>(basic_streambuf<char_type, traits_type>* __sb)
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    __gc_ = 0;
+    sentry __s(*this, true);
+    if (__s)
+    {
+        if (__sb)
+        {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+            try
+            {
+#endif // _LIBCPP_NO_EXCEPTIONS
+                while (true)
+                {
+                    typename traits_type::int_type __i = this->rdbuf()->sgetc();
+                    if (traits_type::eq_int_type(__i, _Traits::eof()))
+                    {
+                       __state |= ios_base::eofbit;
+                       break;
+                    }
+                    if (traits_type::eq_int_type(
+                            __sb->sputc(traits_type::to_char_type(__i)),
+                            traits_type::eof()))
+                        break;
+                    ++__gc_;
+                    this->rdbuf()->sbumpc();
+                }
+                if (__gc_ == 0)
+                   __state |= ios_base::failbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+            }
+            catch (...)
+            {
+                __state |= ios_base::badbit;
+                if (__gc_ == 0)
+                    __state |= ios_base::failbit;
+
+                this->__setstate_nothrow(__state);
+                if (this->exceptions() & ios_base::failbit || this->exceptions() & ios_base::badbit)
+                {
+                    throw;
+                }
+            }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        }
+        else
+        {
+            __state |= ios_base::failbit;
+        }
+        this->setstate(__state);
+    }
+    return *this;
+}
+
+template<class _CharT, class _Traits>
+typename basic_istream<_CharT, _Traits>::int_type
+basic_istream<_CharT, _Traits>::get()
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    __gc_ = 0;
+    int_type __r = traits_type::eof();
+    sentry __s(*this, true);
+    if (__s)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif
+            __r = this->rdbuf()->sbumpc();
+            if (traits_type::eq_int_type(__r, traits_type::eof()))
+               __state |= ios_base::failbit | ios_base::eofbit;
+            else
+                __gc_ = 1;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            this->__setstate_nothrow(this->rdstate() | ios_base::badbit);
+            if (this->exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif
+        this->setstate(__state);
+    }
+    return __r;
+}
+
+template<class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::get(char_type* __s, streamsize __n, char_type __dlm)
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    __gc_ = 0;
+    sentry __sen(*this, true);
+    if (__sen)
+    {
+        if (__n > 0)
+        {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+            try
+            {
+#endif
+                while (__gc_ < __n-1)
+                {
+                    int_type __i = this->rdbuf()->sgetc();
+                    if (traits_type::eq_int_type(__i, traits_type::eof()))
+                    {
+                       __state |= ios_base::eofbit;
+                       break;
+                    }
+                    char_type __ch = traits_type::to_char_type(__i);
+                    if (traits_type::eq(__ch, __dlm))
+                        break;
+                    *__s++ = __ch;
+                    ++__gc_;
+                     this->rdbuf()->sbumpc();
+                }
+                if (__gc_ == 0)
+                   __state |= ios_base::failbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+            }
+            catch (...)
+            {
+                __state |= ios_base::badbit;
+                this->__setstate_nothrow(__state);
+                if (this->exceptions() & ios_base::badbit)
+                {
+                    if (__n > 0)
+                        *__s = char_type();
+                    throw;
+                }
+            }
+#endif
+        }
+        else
+        {
+            __state |= ios_base::failbit;
+        }
+
+        if (__n > 0)
+            *__s = char_type();
+        this->setstate(__state);
+    }
+    if (__n > 0)
+        *__s = char_type();
+    return *this;
+}
+
+template<class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::get(basic_streambuf<char_type, traits_type>& __sb,
+                                    char_type __dlm)
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    __gc_ = 0;
+    sentry __sen(*this, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            while (true)
+            {
+                typename traits_type::int_type __i = this->rdbuf()->sgetc();
+                if (traits_type::eq_int_type(__i, traits_type::eof()))
+                {
+                   __state |= ios_base::eofbit;
+                   break;
+                }
+                char_type __ch = traits_type::to_char_type(__i);
+                if (traits_type::eq(__ch, __dlm))
+                    break;
+                if (traits_type::eq_int_type(__sb.sputc(__ch), traits_type::eof()))
+                    break;
+                ++__gc_;
+                this->rdbuf()->sbumpc();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            // according to the spec, exceptions here are caught but not rethrown
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        if (__gc_ == 0)
+           __state |= ios_base::failbit;
+        this->setstate(__state);
+    }
+    return *this;
+}
+
+template<class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::getline(char_type* __s, streamsize __n, char_type __dlm)
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    __gc_ = 0;
+    sentry __sen(*this, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            while (true)
+            {
+                typename traits_type::int_type __i = this->rdbuf()->sgetc();
+                if (traits_type::eq_int_type(__i, traits_type::eof()))
+                {
+                   __state |= ios_base::eofbit;
+                   break;
+                }
+                char_type __ch = traits_type::to_char_type(__i);
+                if (traits_type::eq(__ch, __dlm))
+                {
+                    this->rdbuf()->sbumpc();
+                    ++__gc_;
+                    break;
+                }
+                if (__gc_ >= __n-1)
+                {
+                    __state |= ios_base::failbit;
+                    break;
+                }
+                *__s++ = __ch;
+                this->rdbuf()->sbumpc();
+                ++__gc_;
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            this->__setstate_nothrow(__state);
+            if (this->exceptions() & ios_base::badbit)
+            {
+                if (__n > 0)
+                    *__s = char_type();
+                if (__gc_ == 0)
+                    __state |= ios_base::failbit;
+                throw;
+            }
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+    if (__n > 0)
+        *__s = char_type();
+    if (__gc_ == 0)
+        __state |= ios_base::failbit;
+    this->setstate(__state);
+    return *this;
+}
+
+template<class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::ignore(streamsize __n, int_type __dlm)
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    __gc_ = 0;
+    sentry __sen(*this, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            if (__n == numeric_limits<streamsize>::max())
+            {
+                while (true)
+                {
+                    typename traits_type::int_type __i = this->rdbuf()->sbumpc();
+                    if (traits_type::eq_int_type(__i, traits_type::eof()))
+                    {
+                       __state |= ios_base::eofbit;
+                       break;
+                    }
+                    ++__gc_;
+                    if (traits_type::eq_int_type(__i, __dlm))
+                        break;
+                }
+            }
+            else
+            {
+                while (__gc_ < __n)
+                {
+                    typename traits_type::int_type __i = this->rdbuf()->sbumpc();
+                    if (traits_type::eq_int_type(__i, traits_type::eof()))
+                    {
+                       __state |= ios_base::eofbit;
+                       break;
+                    }
+                    ++__gc_;
+                    if (traits_type::eq_int_type(__i, __dlm))
+                        break;
+                }
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            this->__setstate_nothrow(__state);
+            if (this->exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        this->setstate(__state);
+    }
+    return *this;
+}
+
+template<class _CharT, class _Traits>
+typename basic_istream<_CharT, _Traits>::int_type
+basic_istream<_CharT, _Traits>::peek()
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    __gc_ = 0;
+    int_type __r = traits_type::eof();
+    sentry __sen(*this, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            __r = this->rdbuf()->sgetc();
+            if (traits_type::eq_int_type(__r, traits_type::eof()))
+                __state |= ios_base::eofbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            this->__setstate_nothrow(__state);
+            if (this->exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        this->setstate(__state);
+    }
+    return __r;
+}
+
+template<class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::read(char_type* __s, streamsize __n)
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    __gc_ = 0;
+    sentry __sen(*this, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            __gc_ = this->rdbuf()->sgetn(__s, __n);
+            if (__gc_ != __n)
+                __state |= ios_base::failbit | ios_base::eofbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            this->__setstate_nothrow(__state);
+            if (this->exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+    else
+    {
+        __state |= ios_base::failbit;
+    }
+    this->setstate(__state);
+    return *this;
+}
+
+template<class _CharT, class _Traits>
+streamsize
+basic_istream<_CharT, _Traits>::readsome(char_type* __s, streamsize __n)
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    __gc_ = 0;
+    sentry __sen(*this, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            streamsize __c = this->rdbuf()->in_avail();
+            switch (__c)
+            {
+            case -1:
+                __state |= ios_base::eofbit;
+                break;
+            case 0:
+                break;
+            default:
+                __n = _VSTD::min(__c, __n);
+                __gc_ = this->rdbuf()->sgetn(__s, __n);
+                if (__gc_ != __n)
+                    __state |= ios_base::failbit | ios_base::eofbit;
+                break;
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            this->__setstate_nothrow(__state);
+            if (this->exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+    else
+    {
+        __state |= ios_base::failbit;
+    }
+    this->setstate(__state);
+    return __gc_;
+}
+
+template<class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::putback(char_type __c)
+{
+    ios_base::iostate __state = this->rdstate() & ~ios_base::eofbit;
+    __gc_ = 0;
+    this->clear(__state);
+    sentry __sen(*this, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            if (this->rdbuf() == nullptr || this->rdbuf()->sputbackc(__c) == traits_type::eof())
+                __state |= ios_base::badbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            this->__setstate_nothrow(__state);
+            if (this->exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+    else
+    {
+        __state |= ios_base::failbit;
+    }
+    this->setstate(__state);
+    return *this;
+}
+
+template<class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::unget()
+{
+    ios_base::iostate __state = this->rdstate() & ~ios_base::eofbit;
+    __gc_ = 0;
+    this->clear(__state);
+    sentry __sen(*this, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            if (this->rdbuf() == nullptr || this->rdbuf()->sungetc() == traits_type::eof())
+                __state |= ios_base::badbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            this->__setstate_nothrow(__state);
+            if (this->exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+    else
+    {
+        __state |= ios_base::failbit;
+    }
+    this->setstate(__state);
+    return *this;
+}
+
+template<class _CharT, class _Traits>
+int
+basic_istream<_CharT, _Traits>::sync()
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    int __r = 0;
+    sentry __sen(*this, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            if (this->rdbuf() == nullptr)
+                return -1;
+            if (this->rdbuf()->pubsync() == -1)
+            {
+                __state |= ios_base::badbit;
+                return -1;
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            this->__setstate_nothrow(__state);
+            if (this->exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        this->setstate(__state);
+    }
+    return __r;
+}
+
+template<class _CharT, class _Traits>
+typename basic_istream<_CharT, _Traits>::pos_type
+basic_istream<_CharT, _Traits>::tellg()
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    pos_type __r(-1);
+    sentry __sen(*this, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __r = this->rdbuf()->pubseekoff(0, ios_base::cur, ios_base::in);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            this->__setstate_nothrow(__state);
+            if (this->exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        this->setstate(__state);
+    }
+    return __r;
+}
+
+template<class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::seekg(pos_type __pos)
+{
+    ios_base::iostate __state = this->rdstate() & ~ios_base::eofbit;
+    this->clear(__state);
+    sentry __sen(*this, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            if (this->rdbuf()->pubseekpos(__pos, ios_base::in) == pos_type(-1))
+                __state |= ios_base::failbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            this->__setstate_nothrow(__state);
+            if (this->exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        this->setstate(__state);
+    }
+    return *this;
+}
+
+template<class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+basic_istream<_CharT, _Traits>::seekg(off_type __off, ios_base::seekdir __dir)
+{
+    ios_base::iostate __state = this->rdstate() & ~ios_base::eofbit;
+    this->clear(__state);
+    sentry __sen(*this, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            if (this->rdbuf()->pubseekoff(__off, __dir, ios_base::in) == pos_type(-1))
+                __state |= ios_base::failbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            this->__setstate_nothrow(__state);
+            if (this->exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        this->setstate(__state);
+    }
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+ws(basic_istream<_CharT, _Traits>& __is)
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    typename basic_istream<_CharT, _Traits>::sentry __sen(__is, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            const ctype<_CharT>& __ct = use_facet<ctype<_CharT> >(__is.getloc());
+            while (true)
+            {
+                typename _Traits::int_type __i = __is.rdbuf()->sgetc();
+                if (_Traits::eq_int_type(__i, _Traits::eof()))
+                {
+                   __state |= ios_base::eofbit;
+                   break;
+                }
+                if (!__ct.is(__ct.space, _Traits::to_char_type(__i)))
+                    break;
+                __is.rdbuf()->sbumpc();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            __is.__setstate_nothrow(__state);
+            if (__is.exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __is.setstate(__state);
+    }
+    return __is;
+}
+
+template <class _Stream, class _Tp, class = void>
+struct __is_istreamable : false_type { };
+
+template <class _Stream, class _Tp>
+struct __is_istreamable<_Stream, _Tp, decltype(
+    declval<_Stream>() >> declval<_Tp>(), void()
+)> : true_type { };
+
+template <class _Stream, class _Tp, class = typename enable_if<
+    _And<is_base_of<ios_base, _Stream>,
+         __is_istreamable<_Stream&, _Tp&&> >::value
+>::type>
+_LIBCPP_INLINE_VISIBILITY
+_Stream&& operator>>(_Stream&& __is, _Tp&& __x)
+{
+    __is >> _VSTD::forward<_Tp>(__x);
+    return _VSTD::move(__is);
+}
+
+template <class _CharT, class _Traits>
+class _LIBCPP_TEMPLATE_VIS basic_iostream
+    : public basic_istream<_CharT, _Traits>,
+      public basic_ostream<_CharT, _Traits>
+{
+public:
+    // types:
+    typedef _CharT                         char_type;
+    typedef _Traits                        traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    // constructor/destructor
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    explicit basic_iostream(basic_streambuf<char_type, traits_type>* __sb)
+      : basic_istream<_CharT, _Traits>(__sb)
+    {}
+
+    virtual ~basic_iostream();
+protected:
+    inline _LIBCPP_INLINE_VISIBILITY
+    basic_iostream(basic_iostream&& __rhs);
+
+    // assign/swap
+    inline _LIBCPP_INLINE_VISIBILITY
+    basic_iostream& operator=(basic_iostream&& __rhs);
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    void swap(basic_iostream& __rhs)
+    { basic_istream<char_type, traits_type>::swap(__rhs); }
+};
+
+template <class _CharT, class _Traits>
+basic_iostream<_CharT, _Traits>::basic_iostream(basic_iostream&& __rhs)
+    : basic_istream<_CharT, _Traits>(_VSTD::move(__rhs))
+{
+}
+
+template <class _CharT, class _Traits>
+basic_iostream<_CharT, _Traits>&
+basic_iostream<_CharT, _Traits>::operator=(basic_iostream&& __rhs)
+{
+    swap(__rhs);
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_iostream<_CharT, _Traits>::~basic_iostream()
+{
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           basic_string<_CharT, _Traits, _Allocator>& __str)
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    typename basic_istream<_CharT, _Traits>::sentry __sen(__is);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif
+            __str.clear();
+            streamsize __n = __is.width();
+            if (__n <= 0)
+                __n = __str.max_size();
+            if (__n <= 0)
+                __n = numeric_limits<streamsize>::max();
+            streamsize __c = 0;
+            const ctype<_CharT>& __ct = use_facet<ctype<_CharT> >(__is.getloc());
+            while (__c < __n)
+            {
+                typename _Traits::int_type __i = __is.rdbuf()->sgetc();
+                if (_Traits::eq_int_type(__i, _Traits::eof()))
+                {
+                   __state |= ios_base::eofbit;
+                   break;
+                }
+                _CharT __ch = _Traits::to_char_type(__i);
+                if (__ct.is(__ct.space, __ch))
+                    break;
+                __str.push_back(__ch);
+                ++__c;
+                 __is.rdbuf()->sbumpc();
+            }
+            __is.width(0);
+            if (__c == 0)
+               __state |= ios_base::failbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            __is.__setstate_nothrow(__state);
+            if (__is.exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif
+        __is.setstate(__state);
+    }
+    return __is;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_istream<_CharT, _Traits>&
+getline(basic_istream<_CharT, _Traits>& __is,
+        basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm)
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    typename basic_istream<_CharT, _Traits>::sentry __sen(__is, true);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif
+            __str.clear();
+            streamsize __extr = 0;
+            while (true)
+            {
+                typename _Traits::int_type __i = __is.rdbuf()->sbumpc();
+                if (_Traits::eq_int_type(__i, _Traits::eof()))
+                {
+                   __state |= ios_base::eofbit;
+                   break;
+                }
+                ++__extr;
+                _CharT __ch = _Traits::to_char_type(__i);
+                if (_Traits::eq(__ch, __dlm))
+                    break;
+                __str.push_back(__ch);
+                if (__str.size() == __str.max_size())
+                {
+                    __state |= ios_base::failbit;
+                    break;
+                }
+            }
+            if (__extr == 0)
+               __state |= ios_base::failbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            __is.__setstate_nothrow(__state);
+            if (__is.exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif
+        __is.setstate(__state);
+    }
+    return __is;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<_CharT, _Traits>&
+getline(basic_istream<_CharT, _Traits>& __is,
+        basic_string<_CharT, _Traits, _Allocator>& __str)
+{
+    return getline(__is, __str, __is.widen('\n'));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<_CharT, _Traits>&
+getline(basic_istream<_CharT, _Traits>&& __is,
+        basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm)
+{
+    return getline(__is, __str, __dlm);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<_CharT, _Traits>&
+getline(basic_istream<_CharT, _Traits>&& __is,
+        basic_string<_CharT, _Traits, _Allocator>& __str)
+{
+    return getline(__is, __str, __is.widen('\n'));
+}
+
+template <class _CharT, class _Traits, size_t _Size>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, bitset<_Size>& __x)
+{
+    ios_base::iostate __state = ios_base::goodbit;
+    typename basic_istream<_CharT, _Traits>::sentry __sen(__is);
+    if (__sen)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif
+            basic_string<_CharT, _Traits> __str;
+            const ctype<_CharT>& __ct = use_facet<ctype<_CharT> >(__is.getloc());
+            size_t __c = 0;
+            _CharT __zero = __ct.widen('0');
+            _CharT __one = __ct.widen('1');
+            while (__c < _Size)
+            {
+                typename _Traits::int_type __i = __is.rdbuf()->sgetc();
+                if (_Traits::eq_int_type(__i, _Traits::eof()))
+                {
+                   __state |= ios_base::eofbit;
+                   break;
+                }
+                _CharT __ch = _Traits::to_char_type(__i);
+                if (!_Traits::eq(__ch, __zero) && !_Traits::eq(__ch, __one))
+                    break;
+                __str.push_back(__ch);
+                ++__c;
+                 __is.rdbuf()->sbumpc();
+            }
+            __x = bitset<_Size>(__str);
+            if (_Size > 0 && __c == 0)
+               __state |= ios_base::failbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __state |= ios_base::badbit;
+            __is.__setstate_nothrow(__state);
+            if (__is.exceptions() & ios_base::badbit)
+            {
+                throw;
+            }
+        }
+#endif
+        __is.setstate(__state);
+    }
+    return __is;
+}
+
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_istream<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_istream<wchar_t>)
+#endif
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_iostream<char>)
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_ISTREAM
diff --git a/contrib/libs/cxxsupp/libcxx/include/iterator b/contrib/libs/cxxsupp/libcxx/include/iterator
new file mode 100644
index 00000000000..1f34d250f5a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/iterator
@@ -0,0 +1,629 @@
+// -*- C++ -*-
+//===-------------------------- iterator ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_ITERATOR
+#define _LIBCPP_ITERATOR
+
+/*
+    iterator synopsis
+
+#include <concepts>
+
+namespace std
+{
+template<class> struct incrementable_traits;       // since C++20
+template<class T>
+  using iter_difference_t = see below;             // since C++20
+
+template<class> struct indirectly_readable_traits; // since C++20
+template<class T>
+  using iter_value_t = see below;                  // since C++20
+
+template<class Iterator>
+struct iterator_traits;
+
+template<class T>
+  requires is_object_v<T>                    // since C++20
+struct iterator_traits<T*>;
+
+template<dereferenceable T>
+  using iter_reference_t = decltype(*declval<T&>());
+
+namespace ranges::inline unspecified {
+    inline constexpr unspecified iter_move = unspecified; // since C++20, nodiscard as an extension
+}}
+
+template<dereferenceable T>
+  requires ...
+using iter_rvalue_reference_t = decltype(ranges::iter_move(declval<T&>())); // since C++20
+
+// [iterator.concepts], iterator concepts
+// [iterator.concept.readable], concept indirectly_readable
+template<class In>
+  concept indirectly_readable = see below;                      // since C++20
+
+template<indirectly_readable T>
+  using iter_common_reference_t =
+    common_reference_t<iter_reference_t<T>, iter_value_t<T>&>;  // since C++20
+
+// [iterator.concept.writable], concept indirectly_writable
+template<class Out, class T>
+  concept indirectly_writable = see below;                // since C++20
+
+// [iterator.concept.winc], concept weakly_incrementable
+template<class I>
+  concept weakly_incrementable = see below;                // since C++20
+
+// [iterator.concept.inc], concept incrementable
+template<class I>
+  concept incrementable = see below;                       // since C++20
+
+// [iterator.concept.iterator], concept input_or_output_iterator
+  template<class I>
+    concept input_or_output_iterator = see below;          // since C++20
+
+// [iterator.concept.sentinel], concept sentinel_for
+template<class S, class I>
+  concept sentinel_for = see below;                        // since C++20
+
+// [iterator.concept.sizedsentinel], concept sized_sentinel_for
+template<class S, class I>
+  inline constexpr bool disable_sized_sentinel_for = false;
+
+template<class S, class I>
+  concept sized_sentinel_for = see below;
+
+// [iterator.concept.input], concept input_iterator
+template<class I>
+  concept input_iterator = see below;                      // since C++20
+
+// [iterator.concept.output], concept output_iterator
+template<class I, class T>
+  concept output_iterator = see below;                     // since C++20
+
+// [iterator.concept.forward], concept forward_iterator
+template<class I>
+  concept forward_iterator = see below;                    // since C++20
+
+// [iterator.concept.bidir], concept bidirectional_iterator
+template<class I>
+  concept bidirectional_iterator = see below;              // since C++20
+
+// [iterator.concept.random.access], concept random_access_iterator
+template<class I>
+  concept random_access_iterator = see below;              // since C++20
+
+// [indirectcallable]
+// [indirectcallable.indirectinvocable]
+template<class F, class I>
+  concept indirectly_unary_invocable = see below;          // since C++20
+
+template<class F, class I>
+  concept indirectly_regular_unary_invocable = see below;  // since C++20
+
+template<class F, class I>
+  concept indirect_unary_predicate = see below;            // since C++20
+
+template<class F, class I1, class I2>
+  concept indirect_binary_predicate = see below;           // since C++20
+
+template<class F, class I1, class I2 = I1>
+  concept indirect_equivalence_relation = see below;       // since C++20
+
+template<class F, class I1, class I2 = I1>
+  concept indirect_strict_weak_order = see below;          // since C++20
+
+template<class F, class... Is>
+  using indirect_result_t = see below;                     // since C++20
+
+// [projected], projected
+template<indirectly_readable I, indirectly_regular_unary_invocable<I> Proj>
+  struct projected;                                        // since C++20
+
+template<weakly_incrementable I, indirectly_regular_unary_invocable<I> Proj>
+  struct incrementable_traits<projected<I, Proj>>;         // since C++20
+
+// [alg.req.ind.move], concept indirectly_movable
+template<class In, class Out>
+  concept indirectly_movable = see below;                  // since C++20
+
+template<class In, class Out>
+  concept indirectly_movable_storable = see below;         // since C++20
+
+// [alg.req.ind.swap], concept indirectly_swappable
+template<class I1, class I2 = I1>
+  concept indirectly_swappable = see below;                // since C++20
+
+template<input_or_output_iterator I, sentinel_for<I> S>
+  requires (!same_as<I, S> && copyable<I>)
+class common_iterator;                                     // since C++20
+
+template<class Category, class T, class Distance = ptrdiff_t,
+         class Pointer = T*, class Reference = T&>
+struct iterator                                            // deprecated in C++17
+{
+    typedef T         value_type;
+    typedef Distance  difference_type;
+    typedef Pointer   pointer;
+    typedef Reference reference;
+    typedef Category  iterator_category;
+};
+
+struct input_iterator_tag  {};
+struct output_iterator_tag {};
+struct forward_iterator_tag       : public input_iterator_tag         {};
+struct bidirectional_iterator_tag : public forward_iterator_tag       {};
+struct random_access_iterator_tag : public bidirectional_iterator_tag {};
+
+// 27.4.3, iterator operations
+template <class InputIterator, class Distance>  // constexpr in C++17
+  constexpr void advance(InputIterator& i, Distance n);
+
+template <class InputIterator>  // constexpr in C++17
+  constexpr typename iterator_traits<InputIterator>::difference_type
+    distance(InputIterator first, InputIterator last);
+
+template <class InputIterator>  // constexpr in C++17
+  constexpr InputIterator next(InputIterator x,
+typename iterator_traits<InputIterator>::difference_type n = 1);
+
+template <class BidirectionalIterator>  // constexpr in C++17
+  constexpr BidirectionalIterator prev(BidirectionalIterator x,
+    typename iterator_traits<BidirectionalIterator>::difference_type n = 1);
+
+// [range.iter.ops], range iterator operations
+namespace ranges {
+  // [range.iter.op.advance], ranges::advance
+  template<input_or_output_iterator I>
+    constexpr void advance(I& i, iter_difference_t<I> n);                          // since C++20
+  template<input_or_output_iterator I, sentinel_for<I> S>
+    constexpr void advance(I& i, S bound);                                         // since C++20
+  template<input_or_output_iterator I, sentinel_for<I> S>
+    constexpr iter_difference_t<I> advance(I& i, iter_difference_t<I> n, S bound); // since C++20
+}
+
+template <class Iterator>
+class reverse_iterator
+    : public iterator<typename iterator_traits<Iterator>::iterator_category, // until C++17
+                      typename iterator_traits<Iterator>::value_type,
+                      typename iterator_traits<Iterator>::difference_type,
+                      typename iterator_traits<Iterator>::pointer,
+                      typename iterator_traits<Iterator>::reference>
+{
+protected:
+    Iterator current;
+public:
+    typedef Iterator                                            iterator_type;
+    typedef typename iterator_traits<Iterator>::difference_type difference_type;
+    typedef typename iterator_traits<Iterator>::reference       reference;
+    typedef typename iterator_traits<Iterator>::pointer         pointer;
+
+    constexpr reverse_iterator();
+    constexpr explicit reverse_iterator(Iterator x);
+    template <class U> constexpr reverse_iterator(const reverse_iterator<U>& u);
+    template <class U> constexpr reverse_iterator& operator=(const reverse_iterator<U>& u);
+    constexpr Iterator base() const;
+    constexpr reference operator*() const;
+    constexpr pointer   operator->() const;
+    constexpr reverse_iterator& operator++();
+    constexpr reverse_iterator  operator++(int);
+    constexpr reverse_iterator& operator--();
+    constexpr reverse_iterator  operator--(int);
+    constexpr reverse_iterator  operator+ (difference_type n) const;
+    constexpr reverse_iterator& operator+=(difference_type n);
+    constexpr reverse_iterator  operator- (difference_type n) const;
+    constexpr reverse_iterator& operator-=(difference_type n);
+    constexpr reference         operator[](difference_type n) const;
+};
+
+template <class Iterator1, class Iterator2>
+constexpr bool                          // constexpr in C++17
+operator==(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
+
+template <class Iterator1, class Iterator2>
+constexpr bool                          // constexpr in C++17
+operator<(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
+
+template <class Iterator1, class Iterator2>
+constexpr bool                          // constexpr in C++17
+operator!=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
+
+template <class Iterator1, class Iterator2>
+constexpr bool                          // constexpr in C++17
+operator>(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
+
+template <class Iterator1, class Iterator2>
+constexpr bool                          // constexpr in C++17
+operator>=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
+
+template <class Iterator1, class Iterator2>
+constexpr bool                          // constexpr in C++17
+operator<=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
+
+template <class Iterator1, class Iterator2>
+constexpr auto
+operator-(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y)
+-> decltype(__y.base() - __x.base());   // constexpr in C++17
+
+template <class Iterator>
+constexpr reverse_iterator<Iterator>
+operator+(typename reverse_iterator<Iterator>::difference_type n,
+          const reverse_iterator<Iterator>& x);   // constexpr in C++17
+
+template <class Iterator>
+constexpr reverse_iterator<Iterator> make_reverse_iterator(Iterator i); // C++14, constexpr in C++17
+
+template <class Container>
+class back_insert_iterator
+    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
+{
+protected:
+    Container* container;
+public:
+    typedef Container                   container_type;
+    typedef void                        value_type;
+    typedef void                        difference_type; // until C++20
+    typedef ptrdiff_t                   difference_type; // since C++20
+    typedef void                        reference;
+    typedef void                        pointer;
+
+    explicit back_insert_iterator(Container& x);  // constexpr in C++20
+    back_insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
+    back_insert_iterator& operator*();  // constexpr in C++20
+    back_insert_iterator& operator++();  // constexpr in C++20
+    back_insert_iterator  operator++(int);  // constexpr in C++20
+};
+
+template <class Container> back_insert_iterator<Container> back_inserter(Container& x);  // constexpr in C++20
+
+template <class Container>
+class front_insert_iterator
+    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
+{
+protected:
+    Container* container;
+public:
+    typedef Container                    container_type;
+    typedef void                         value_type;
+    typedef void                         difference_type; // until C++20
+    typedef ptrdiff_t                    difference_type; // since C++20
+    typedef void                         reference;
+    typedef void                         pointer;
+
+    explicit front_insert_iterator(Container& x);  // constexpr in C++20
+    front_insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
+    front_insert_iterator& operator*();  // constexpr in C++20
+    front_insert_iterator& operator++();  // constexpr in C++20
+    front_insert_iterator  operator++(int);  // constexpr in C++20
+};
+
+template <class Container> front_insert_iterator<Container> front_inserter(Container& x);  // constexpr in C++20
+
+template <class Container>
+class insert_iterator
+    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
+{
+protected:
+    Container* container;
+    typename Container::iterator iter;
+public:
+    typedef Container              container_type;
+    typedef void                   value_type;
+    typedef void                   difference_type; // until C++20
+    typedef ptrdiff_t              difference_type; // since C++20
+    typedef void                   reference;
+    typedef void                   pointer;
+
+    insert_iterator(Container& x, typename Container::iterator i);  // constexpr in C++20
+    insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
+    insert_iterator& operator*();  // constexpr in C++20
+    insert_iterator& operator++();  // constexpr in C++20
+    insert_iterator& operator++(int);  // constexpr in C++20
+};
+
+template <class Container, class Iterator>
+insert_iterator<Container> inserter(Container& x, Iterator i);  // constexpr in C++20
+
+template <class Iterator>
+class move_iterator {
+public:
+    typedef Iterator                                              iterator_type;
+    typedef typename iterator_traits<Iterator>::difference_type   difference_type;
+    typedef Iterator                                              pointer;
+    typedef typename iterator_traits<Iterator>::value_type        value_type;
+    typedef typename iterator_traits<Iterator>::iterator_category iterator_category;
+    typedef value_type&&                                          reference;
+
+    constexpr move_iterator();  // all the constexprs are in C++17
+    constexpr explicit move_iterator(Iterator i);
+    template <class U>
+      constexpr move_iterator(const move_iterator<U>& u);
+    template <class U>
+      constexpr move_iterator& operator=(const move_iterator<U>& u);
+    constexpr iterator_type base() const;
+    constexpr reference operator*() const;
+    constexpr pointer operator->() const;
+    constexpr move_iterator& operator++();
+    constexpr move_iterator operator++(int);
+    constexpr move_iterator& operator--();
+    constexpr move_iterator operator--(int);
+    constexpr move_iterator operator+(difference_type n) const;
+    constexpr move_iterator& operator+=(difference_type n);
+    constexpr move_iterator operator-(difference_type n) const;
+    constexpr move_iterator& operator-=(difference_type n);
+    constexpr unspecified operator[](difference_type n) const;
+private:
+    Iterator current; // exposition only
+};
+
+template <class Iterator1, class Iterator2>
+constexpr bool   // constexpr in C++17
+operator==(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
+
+template <class Iterator1, class Iterator2>
+constexpr bool   // constexpr in C++17
+operator!=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
+
+template <class Iterator1, class Iterator2>
+constexpr bool   // constexpr in C++17
+operator<(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
+
+template <class Iterator1, class Iterator2>
+constexpr bool   // constexpr in C++17
+operator<=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
+
+template <class Iterator1, class Iterator2>
+constexpr bool   // constexpr in C++17
+operator>(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
+
+template <class Iterator1, class Iterator2>
+constexpr bool   // constexpr in C++17
+operator>=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
+
+template <class Iterator1, class Iterator2>
+constexpr auto   // constexpr in C++17
+operator-(const move_iterator<Iterator1>& x,
+          const move_iterator<Iterator2>& y) -> decltype(x.base() - y.base());
+
+template <class Iterator>
+constexpr move_iterator<Iterator> operator+(   // constexpr in C++17
+            typename move_iterator<Iterator>::difference_type n,
+            const move_iterator<Iterator>& x);
+
+template <class Iterator>   // constexpr in C++17
+constexpr  move_iterator<Iterator> make_move_iterator(const Iterator& i);
+
+// [default.sentinel], default sentinel
+struct default_sentinel_t;
+inline constexpr default_sentinel_t default_sentinel{};
+
+// [iterators.counted], counted iterators
+template<input_or_output_iterator I> class counted_iterator;
+
+template<input_iterator I>
+  requires see below
+  struct iterator_traits<counted_iterator<I>>;
+
+// [unreachable.sentinel], unreachable sentinel
+struct unreachable_sentinel_t;
+inline constexpr unreachable_sentinel_t unreachable_sentinel{};
+
+template <class T, class charT = char, class traits = char_traits<charT>, class Distance = ptrdiff_t>
+class istream_iterator
+    : public iterator<input_iterator_tag, T, Distance, const T*, const T&> // until C++17
+{
+public:
+    typedef input_iterator_tag           iterator_category;
+    typedef T                            value_type;
+    typedef Distance                     difference_type;
+    typedef const T*                     pointer;
+    typedef const T&                     reference;
+
+    typedef charT                        char_type;
+    typedef traits                       traits_type;
+    typedef basic_istream<charT, traits> istream_type;
+
+    constexpr istream_iterator();
+    istream_iterator(istream_type& s);
+    istream_iterator(const istream_iterator& x);
+    ~istream_iterator();
+
+    const T& operator*() const;
+    const T* operator->() const;
+    istream_iterator& operator++();
+    istream_iterator  operator++(int);
+};
+
+template <class T, class charT, class traits, class Distance>
+bool operator==(const istream_iterator<T,charT,traits,Distance>& x,
+                const istream_iterator<T,charT,traits,Distance>& y);
+template <class T, class charT, class traits, class Distance>
+bool operator!=(const istream_iterator<T,charT,traits,Distance>& x,
+                const istream_iterator<T,charT,traits,Distance>& y);
+
+template <class T, class charT = char, class traits = char_traits<charT> >
+class ostream_iterator
+    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
+{
+public:
+    typedef output_iterator_tag         iterator_category;
+    typedef void                        value_type;
+    typedef void                        difference_type; // until C++20
+    typedef ptrdiff_t                   difference_type; // since C++20
+    typedef void                        pointer;
+    typedef void                        reference;
+
+    typedef charT char_type;
+    typedef traits traits_type;
+    typedef basic_ostream<charT,traits> ostream_type;
+
+    ostream_iterator(ostream_type& s);
+    ostream_iterator(ostream_type& s, const charT* delimiter);
+    ostream_iterator(const ostream_iterator& x);
+    ~ostream_iterator();
+    ostream_iterator& operator=(const T& value);
+
+    ostream_iterator& operator*();
+    ostream_iterator& operator++();
+    ostream_iterator& operator++(int);
+};
+
+template<class charT, class traits = char_traits<charT> >
+class istreambuf_iterator
+    : public iterator<input_iterator_tag, charT, traits::off_type, unspecified, charT> // until C++17
+{
+public:
+    typedef input_iterator_tag              iterator_category;
+    typedef charT                           value_type;
+    typedef traits::off_type                difference_type;
+    typedef unspecified                     pointer;
+    typedef charT                           reference;
+
+    typedef charT                           char_type;
+    typedef traits                          traits_type;
+    typedef traits::int_type                int_type;
+    typedef basic_streambuf<charT, traits>  streambuf_type;
+    typedef basic_istream<charT, traits>    istream_type;
+
+    istreambuf_iterator() noexcept;
+    istreambuf_iterator(istream_type& s) noexcept;
+    istreambuf_iterator(streambuf_type* s) noexcept;
+    istreambuf_iterator(a-private-type) noexcept;
+
+    charT                operator*() const;
+    pointer operator->() const;
+    istreambuf_iterator& operator++();
+    a-private-type       operator++(int);
+
+    bool equal(const istreambuf_iterator& b) const;
+};
+
+template <class charT, class traits>
+bool operator==(const istreambuf_iterator<charT,traits>& a,
+                const istreambuf_iterator<charT,traits>& b);
+template <class charT, class traits>
+bool operator!=(const istreambuf_iterator<charT,traits>& a,
+                const istreambuf_iterator<charT,traits>& b);
+
+template <class charT, class traits = char_traits<charT> >
+class ostreambuf_iterator
+    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
+{
+public:
+    typedef output_iterator_tag            iterator_category;
+    typedef void                           value_type;
+    typedef void                           difference_type; // until C++20
+    typedef ptrdiff_t                      difference_type; // since C++20
+    typedef void                           pointer;
+    typedef void                           reference;
+
+    typedef charT                          char_type;
+    typedef traits                         traits_type;
+    typedef basic_streambuf<charT, traits> streambuf_type;
+    typedef basic_ostream<charT, traits>   ostream_type;
+
+    ostreambuf_iterator(ostream_type& s) noexcept;
+    ostreambuf_iterator(streambuf_type* s) noexcept;
+    ostreambuf_iterator& operator=(charT c);
+    ostreambuf_iterator& operator*();
+    ostreambuf_iterator& operator++();
+    ostreambuf_iterator& operator++(int);
+    bool failed() const noexcept;
+};
+
+template <class C> constexpr auto begin(C& c) -> decltype(c.begin());
+template <class C> constexpr auto begin(const C& c) -> decltype(c.begin());
+template <class C> constexpr auto end(C& c) -> decltype(c.end());
+template <class C> constexpr auto end(const C& c) -> decltype(c.end());
+template <class T, size_t N> constexpr T* begin(T (&array)[N]);
+template <class T, size_t N> constexpr T* end(T (&array)[N]);
+
+template <class C> auto constexpr cbegin(const C& c) -> decltype(std::begin(c));        // C++14
+template <class C> auto constexpr cend(const C& c) -> decltype(std::end(c));            // C++14
+template <class C> auto constexpr rbegin(C& c) -> decltype(c.rbegin());                 // C++14
+template <class C> auto constexpr rbegin(const C& c) -> decltype(c.rbegin());           // C++14
+template <class C> auto constexpr rend(C& c) -> decltype(c.rend());                     // C++14
+template <class C> constexpr auto rend(const C& c) -> decltype(c.rend());               // C++14
+template <class E> reverse_iterator<const E*> constexpr rbegin(initializer_list<E> il); // C++14
+template <class E> reverse_iterator<const E*> constexpr rend(initializer_list<E> il);   // C++14
+template <class T, size_t N> reverse_iterator<T*> constexpr rbegin(T (&array)[N]);      // C++14
+template <class T, size_t N> reverse_iterator<T*> constexpr rend(T (&array)[N]);        // C++14
+template <class C> constexpr auto crbegin(const C& c) -> decltype(std::rbegin(c));      // C++14
+template <class C> constexpr auto crend(const C& c) -> decltype(std::rend(c));          // C++14
+
+// 24.8, container access:
+template <class C> constexpr auto size(const C& c) -> decltype(c.size());         // C++17
+template <class T, size_t N> constexpr size_t size(const T (&array)[N]) noexcept; // C++17
+
+template <class C> constexpr auto ssize(const C& c)
+    -> common_type_t<ptrdiff_t, make_signed_t<decltype(c.size())>>;                    // C++20
+template <class T, ptrdiff_t> constexpr ptrdiff_t ssize(const T (&array)[N]) noexcept; // C++20
+
+template <class C> constexpr auto empty(const C& c) -> decltype(c.empty());       // C++17
+template <class T, size_t N> constexpr bool empty(const T (&array)[N]) noexcept;  // C++17
+template <class E> constexpr bool empty(initializer_list<E> il) noexcept;         // C++17
+template <class C> constexpr auto data(C& c) -> decltype(c.data());               // C++17
+template <class C> constexpr auto data(const C& c) -> decltype(c.data());         // C++17
+template <class T, size_t N> constexpr T* data(T (&array)[N]) noexcept;           // C++17
+template <class E> constexpr const E* data(initializer_list<E> il) noexcept;      // C++17
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__functional_base>
+#include <__iterator/access.h>
+#include <__iterator/advance.h>
+#include <__iterator/back_insert_iterator.h>
+#include <__iterator/common_iterator.h>
+#include <__iterator/concepts.h>
+#include <__iterator/counted_iterator.h>
+#include <__iterator/data.h>
+#include <__iterator/default_sentinel.h>
+#include <__iterator/distance.h>
+#include <__iterator/empty.h>
+#include <__iterator/erase_if_container.h>
+#include <__iterator/front_insert_iterator.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/insert_iterator.h>
+#include <__iterator/istreambuf_iterator.h>
+#include <__iterator/istream_iterator.h>
+#include <__iterator/iterator.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/iter_move.h>
+#include <__iterator/iter_swap.h>
+#include <__iterator/move_iterator.h>
+#include <__iterator/next.h>
+#include <__iterator/ostreambuf_iterator.h>
+#include <__iterator/ostream_iterator.h>
+#include <__iterator/prev.h>
+#include <__iterator/projected.h>
+#include <__iterator/readable_traits.h>
+#include <__iterator/reverse_access.h>
+#include <__iterator/reverse_iterator.h>
+#include <__iterator/size.h>
+#include <__iterator/unreachable_sentinel.h>
+#include <__iterator/wrap_iter.h>
+#include <__memory/addressof.h>
+#include <__memory/pointer_traits.h>
+#include <__utility/forward.h>
+#include <compare>
+#include <concepts> // Mandated by the Standard.
+#include <cstddef>
+#include <initializer_list>
+#include <type_traits>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#endif // _LIBCPP_ITERATOR
diff --git a/contrib/libs/cxxsupp/libcxx/include/latch b/contrib/libs/cxxsupp/libcxx/include/latch
new file mode 100644
index 00000000000..10ae5721fbe
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/latch
@@ -0,0 +1,112 @@
+// -*- C++ -*-
+//===--------------------------- latch -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_LATCH
+#define _LIBCPP_LATCH
+
+/*
+    latch synopsis
+
+namespace std
+{
+
+  class latch
+  {
+  public:
+    static constexpr ptrdiff_t max() noexcept;
+
+    constexpr explicit latch(ptrdiff_t __expected);
+    ~latch();
+
+    latch(const latch&) = delete;
+    latch& operator=(const latch&) = delete;
+
+    void count_down(ptrdiff_t __update = 1);
+    bool try_wait() const noexcept;
+    void wait() const;
+    void arrive_and_wait(ptrdiff_t __update = 1);
+
+  private:
+    ptrdiff_t __counter; // exposition only
+  };
+
+}
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <atomic>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_HAS_NO_THREADS
+# error <latch> is not supported on this single threaded system
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#if _LIBCPP_STD_VER >= 14
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+class latch
+{
+    __atomic_base<ptrdiff_t> __a;
+
+public:
+    static constexpr ptrdiff_t max() noexcept {
+        return numeric_limits<ptrdiff_t>::max();
+    }
+
+    inline _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit latch(ptrdiff_t __expected) : __a(__expected) { }
+
+    ~latch() = default;
+    latch(const latch&) = delete;
+    latch& operator=(const latch&) = delete;
+
+    inline _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void count_down(ptrdiff_t __update = 1)
+    {
+        auto const __old = __a.fetch_sub(__update, memory_order_release);
+        if(__old == __update)
+            __a.notify_all();
+    }
+    inline _LIBCPP_INLINE_VISIBILITY
+    bool try_wait() const noexcept
+    {
+        return 0 == __a.load(memory_order_acquire);
+    }
+    inline _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void wait() const
+    {
+        auto const __test_fn = [=]() -> bool {
+            return try_wait();
+        };
+        __cxx_atomic_wait(&__a.__a_, __test_fn);
+    }
+    inline _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void arrive_and_wait(ptrdiff_t __update = 1)
+    {
+        count_down(__update);
+        wait();
+    }
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 14
+
+_LIBCPP_POP_MACROS
+
+#endif //_LIBCPP_LATCH
diff --git a/contrib/libs/cxxsupp/libcxx/include/limits b/contrib/libs/cxxsupp/libcxx/include/limits
new file mode 100644
index 00000000000..a6d51785249
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/limits
@@ -0,0 +1,818 @@
+// -*- C++ -*-
+//===---------------------------- limits ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_LIMITS
+#define _LIBCPP_LIMITS
+
+/*
+    limits synopsis
+
+namespace std
+{
+
+template<class T>
+class numeric_limits
+{
+public:
+    static constexpr bool is_specialized = false;
+    static constexpr T min() noexcept;
+    static constexpr T max() noexcept;
+    static constexpr T lowest() noexcept;
+
+    static constexpr int  digits = 0;
+    static constexpr int  digits10 = 0;
+    static constexpr int  max_digits10 = 0;
+    static constexpr bool is_signed = false;
+    static constexpr bool is_integer = false;
+    static constexpr bool is_exact = false;
+    static constexpr int  radix = 0;
+    static constexpr T epsilon() noexcept;
+    static constexpr T round_error() noexcept;
+
+    static constexpr int  min_exponent = 0;
+    static constexpr int  min_exponent10 = 0;
+    static constexpr int  max_exponent = 0;
+    static constexpr int  max_exponent10 = 0;
+
+    static constexpr bool has_infinity = false;
+    static constexpr bool has_quiet_NaN = false;
+    static constexpr bool has_signaling_NaN = false;
+    static constexpr float_denorm_style has_denorm = denorm_absent;
+    static constexpr bool has_denorm_loss = false;
+    static constexpr T infinity() noexcept;
+    static constexpr T quiet_NaN() noexcept;
+    static constexpr T signaling_NaN() noexcept;
+    static constexpr T denorm_min() noexcept;
+
+    static constexpr bool is_iec559 = false;
+    static constexpr bool is_bounded = false;
+    static constexpr bool is_modulo = false;
+
+    static constexpr bool traps = false;
+    static constexpr bool tinyness_before = false;
+    static constexpr float_round_style round_style = round_toward_zero;
+};
+
+enum float_round_style
+{
+    round_indeterminate       = -1,
+    round_toward_zero         =  0,
+    round_to_nearest          =  1,
+    round_toward_infinity     =  2,
+    round_toward_neg_infinity =  3
+};
+
+enum float_denorm_style
+{
+    denorm_indeterminate = -1,
+    denorm_absent = 0,
+    denorm_present = 1
+};
+
+template<> class numeric_limits<cv bool>;
+
+template<> class numeric_limits<cv char>;
+template<> class numeric_limits<cv signed char>;
+template<> class numeric_limits<cv unsigned char>;
+template<> class numeric_limits<cv wchar_t>;
+template<> class numeric_limits<cv char8_t>; // C++20
+template<> class numeric_limits<cv char16_t>;
+template<> class numeric_limits<cv char32_t>;
+
+template<> class numeric_limits<cv short>;
+template<> class numeric_limits<cv int>;
+template<> class numeric_limits<cv long>;
+template<> class numeric_limits<cv long long>;
+template<> class numeric_limits<cv unsigned short>;
+template<> class numeric_limits<cv unsigned int>;
+template<> class numeric_limits<cv unsigned long>;
+template<> class numeric_limits<cv unsigned long long>;
+
+template<> class numeric_limits<cv float>;
+template<> class numeric_limits<cv double>;
+template<> class numeric_limits<cv long double>;
+
+}  // std
+
+*/
+#include <__config>
+#include <type_traits>
+
+#if defined(_LIBCPP_COMPILER_MSVC)
+#include "__support/win32/limits_msvc_win32.h"
+#endif // _LIBCPP_MSVCRT
+
+#if defined(__IBMCPP__)
+#include "__support/ibm/limits.h"
+#endif // __IBMCPP__
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+#include <version>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+enum float_round_style
+{
+    round_indeterminate       = -1,
+    round_toward_zero         =  0,
+    round_to_nearest          =  1,
+    round_toward_infinity     =  2,
+    round_toward_neg_infinity =  3
+};
+
+enum float_denorm_style
+{
+    denorm_indeterminate = -1,
+    denorm_absent = 0,
+    denorm_present = 1
+};
+
+template <class _Tp, bool = is_arithmetic<_Tp>::value>
+class __libcpp_numeric_limits
+{
+protected:
+    typedef _Tp type;
+
+    static _LIBCPP_CONSTEXPR const  bool is_specialized = false;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type min() _NOEXCEPT {return type();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type max() _NOEXCEPT {return type();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT {return type();}
+
+    static _LIBCPP_CONSTEXPR const int  digits = 0;
+    static _LIBCPP_CONSTEXPR const int  digits10 = 0;
+    static _LIBCPP_CONSTEXPR const int  max_digits10 = 0;
+    static _LIBCPP_CONSTEXPR const bool is_signed = false;
+    static _LIBCPP_CONSTEXPR const bool is_integer = false;
+    static _LIBCPP_CONSTEXPR const bool is_exact = false;
+    static _LIBCPP_CONSTEXPR const int  radix = 0;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT {return type();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT {return type();}
+
+    static _LIBCPP_CONSTEXPR const int  min_exponent = 0;
+    static _LIBCPP_CONSTEXPR const int  min_exponent10 = 0;
+    static _LIBCPP_CONSTEXPR const int  max_exponent = 0;
+    static _LIBCPP_CONSTEXPR const int  max_exponent10 = 0;
+
+    static _LIBCPP_CONSTEXPR const bool has_infinity = false;
+    static _LIBCPP_CONSTEXPR const bool has_quiet_NaN = false;
+    static _LIBCPP_CONSTEXPR const bool has_signaling_NaN = false;
+    static _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = denorm_absent;
+    static _LIBCPP_CONSTEXPR const bool has_denorm_loss = false;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT {return type();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT {return type();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT {return type();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT {return type();}
+
+    static _LIBCPP_CONSTEXPR const bool is_iec559 = false;
+    static _LIBCPP_CONSTEXPR const bool is_bounded = false;
+    static _LIBCPP_CONSTEXPR const bool is_modulo = false;
+
+    static _LIBCPP_CONSTEXPR const bool traps = false;
+    static _LIBCPP_CONSTEXPR const bool tinyness_before = false;
+    static _LIBCPP_CONSTEXPR const float_round_style round_style = round_toward_zero;
+};
+
+template <class _Tp, int __digits, bool _IsSigned>
+struct __libcpp_compute_min
+{
+    static _LIBCPP_CONSTEXPR const _Tp value = _Tp(_Tp(1) << __digits);
+};
+
+template <class _Tp, int __digits>
+struct __libcpp_compute_min<_Tp, __digits, false>
+{
+    static _LIBCPP_CONSTEXPR const _Tp value = _Tp(0);
+};
+
+template <class _Tp>
+class __libcpp_numeric_limits<_Tp, true>
+{
+protected:
+    typedef _Tp type;
+
+    static _LIBCPP_CONSTEXPR const bool is_specialized = true;
+
+    static _LIBCPP_CONSTEXPR const bool is_signed = type(-1) < type(0);
+    static _LIBCPP_CONSTEXPR const int  digits = static_cast<int>(sizeof(type) * __CHAR_BIT__ - is_signed);
+    static _LIBCPP_CONSTEXPR const int  digits10 = digits * 3 / 10;
+    static _LIBCPP_CONSTEXPR const int  max_digits10 = 0;
+    static _LIBCPP_CONSTEXPR const type __min = __libcpp_compute_min<type, digits, is_signed>::value;
+    static _LIBCPP_CONSTEXPR const type __max = is_signed ? type(type(~0) ^ __min) : type(~0);
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type min() _NOEXCEPT {return __min;}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type max() _NOEXCEPT {return __max;}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT {return min();}
+
+    static _LIBCPP_CONSTEXPR const bool is_integer = true;
+    static _LIBCPP_CONSTEXPR const bool is_exact = true;
+    static _LIBCPP_CONSTEXPR const int  radix = 2;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT {return type(0);}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT {return type(0);}
+
+    static _LIBCPP_CONSTEXPR const int  min_exponent = 0;
+    static _LIBCPP_CONSTEXPR const int  min_exponent10 = 0;
+    static _LIBCPP_CONSTEXPR const int  max_exponent = 0;
+    static _LIBCPP_CONSTEXPR const int  max_exponent10 = 0;
+
+    static _LIBCPP_CONSTEXPR const bool has_infinity = false;
+    static _LIBCPP_CONSTEXPR const bool has_quiet_NaN = false;
+    static _LIBCPP_CONSTEXPR const bool has_signaling_NaN = false;
+    static _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = denorm_absent;
+    static _LIBCPP_CONSTEXPR const bool has_denorm_loss = false;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT {return type(0);}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT {return type(0);}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT {return type(0);}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT {return type(0);}
+
+    static _LIBCPP_CONSTEXPR const bool is_iec559 = false;
+    static _LIBCPP_CONSTEXPR const bool is_bounded = true;
+    static _LIBCPP_CONSTEXPR const bool is_modulo = !_VSTD::is_signed<_Tp>::value;
+
+#if defined(__i386__) || defined(__x86_64__) || defined(__pnacl__) || \
+    defined(__wasm__)
+    static _LIBCPP_CONSTEXPR const bool traps = true;
+#else
+    static _LIBCPP_CONSTEXPR const bool traps = false;
+#endif
+    static _LIBCPP_CONSTEXPR const bool tinyness_before = false;
+    static _LIBCPP_CONSTEXPR const float_round_style round_style = round_toward_zero;
+};
+
+template <>
+class __libcpp_numeric_limits<bool, true>
+{
+protected:
+    typedef bool type;
+
+    static _LIBCPP_CONSTEXPR const bool is_specialized = true;
+
+    static _LIBCPP_CONSTEXPR const bool is_signed = false;
+    static _LIBCPP_CONSTEXPR const int  digits = 1;
+    static _LIBCPP_CONSTEXPR const int  digits10 = 0;
+    static _LIBCPP_CONSTEXPR const int  max_digits10 = 0;
+    static _LIBCPP_CONSTEXPR const type __min = false;
+    static _LIBCPP_CONSTEXPR const type __max = true;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type min() _NOEXCEPT {return __min;}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type max() _NOEXCEPT {return __max;}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT {return min();}
+
+    static _LIBCPP_CONSTEXPR const bool is_integer = true;
+    static _LIBCPP_CONSTEXPR const bool is_exact = true;
+    static _LIBCPP_CONSTEXPR const int  radix = 2;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT {return type(0);}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT {return type(0);}
+
+    static _LIBCPP_CONSTEXPR const int  min_exponent = 0;
+    static _LIBCPP_CONSTEXPR const int  min_exponent10 = 0;
+    static _LIBCPP_CONSTEXPR const int  max_exponent = 0;
+    static _LIBCPP_CONSTEXPR const int  max_exponent10 = 0;
+
+    static _LIBCPP_CONSTEXPR const bool has_infinity = false;
+    static _LIBCPP_CONSTEXPR const bool has_quiet_NaN = false;
+    static _LIBCPP_CONSTEXPR const bool has_signaling_NaN = false;
+    static _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = denorm_absent;
+    static _LIBCPP_CONSTEXPR const bool has_denorm_loss = false;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT {return type(0);}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT {return type(0);}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT {return type(0);}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT {return type(0);}
+
+    static _LIBCPP_CONSTEXPR const bool is_iec559 = false;
+    static _LIBCPP_CONSTEXPR const bool is_bounded = true;
+    static _LIBCPP_CONSTEXPR const bool is_modulo = false;
+
+    static _LIBCPP_CONSTEXPR const bool traps = false;
+    static _LIBCPP_CONSTEXPR const bool tinyness_before = false;
+    static _LIBCPP_CONSTEXPR const float_round_style round_style = round_toward_zero;
+};
+
+template <>
+class __libcpp_numeric_limits<float, true>
+{
+protected:
+    typedef float type;
+
+    static _LIBCPP_CONSTEXPR const bool is_specialized = true;
+
+    static _LIBCPP_CONSTEXPR const bool is_signed = true;
+    static _LIBCPP_CONSTEXPR const int  digits = __FLT_MANT_DIG__;
+    static _LIBCPP_CONSTEXPR const int  digits10 = __FLT_DIG__;
+    static _LIBCPP_CONSTEXPR const int  max_digits10 = 2+(digits * 30103l)/100000l;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type min() _NOEXCEPT {return __FLT_MIN__;}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type max() _NOEXCEPT {return __FLT_MAX__;}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT {return -max();}
+
+    static _LIBCPP_CONSTEXPR const bool is_integer = false;
+    static _LIBCPP_CONSTEXPR const bool is_exact = false;
+    static _LIBCPP_CONSTEXPR const int  radix = __FLT_RADIX__;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT {return __FLT_EPSILON__;}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT {return 0.5F;}
+
+    static _LIBCPP_CONSTEXPR const int  min_exponent = __FLT_MIN_EXP__;
+    static _LIBCPP_CONSTEXPR const int  min_exponent10 = __FLT_MIN_10_EXP__;
+    static _LIBCPP_CONSTEXPR const int  max_exponent = __FLT_MAX_EXP__;
+    static _LIBCPP_CONSTEXPR const int  max_exponent10 = __FLT_MAX_10_EXP__;
+
+    static _LIBCPP_CONSTEXPR const bool has_infinity = true;
+    static _LIBCPP_CONSTEXPR const bool has_quiet_NaN = true;
+    static _LIBCPP_CONSTEXPR const bool has_signaling_NaN = true;
+    static _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = denorm_present;
+    static _LIBCPP_CONSTEXPR const bool has_denorm_loss = false;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT {return __builtin_huge_valf();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT {return __builtin_nanf("");}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT {return __builtin_nansf("");}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT {return __FLT_DENORM_MIN__;}
+
+    static _LIBCPP_CONSTEXPR const bool is_iec559 = true;
+    static _LIBCPP_CONSTEXPR const bool is_bounded = true;
+    static _LIBCPP_CONSTEXPR const bool is_modulo = false;
+
+    static _LIBCPP_CONSTEXPR const bool traps = false;
+    static _LIBCPP_CONSTEXPR const bool tinyness_before = false;
+    static _LIBCPP_CONSTEXPR const float_round_style round_style = round_to_nearest;
+};
+
+template <>
+class __libcpp_numeric_limits<double, true>
+{
+protected:
+    typedef double type;
+
+    static _LIBCPP_CONSTEXPR const bool is_specialized = true;
+
+    static _LIBCPP_CONSTEXPR const bool is_signed = true;
+    static _LIBCPP_CONSTEXPR const int  digits = __DBL_MANT_DIG__;
+    static _LIBCPP_CONSTEXPR const int  digits10 = __DBL_DIG__;
+    static _LIBCPP_CONSTEXPR const int  max_digits10 = 2+(digits * 30103l)/100000l;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type min() _NOEXCEPT {return __DBL_MIN__;}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type max() _NOEXCEPT {return __DBL_MAX__;}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT {return -max();}
+
+    static _LIBCPP_CONSTEXPR const bool is_integer = false;
+    static _LIBCPP_CONSTEXPR const bool is_exact = false;
+    static _LIBCPP_CONSTEXPR const int  radix = __FLT_RADIX__;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT {return __DBL_EPSILON__;}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT {return 0.5;}
+
+    static _LIBCPP_CONSTEXPR const int  min_exponent = __DBL_MIN_EXP__;
+    static _LIBCPP_CONSTEXPR const int  min_exponent10 = __DBL_MIN_10_EXP__;
+    static _LIBCPP_CONSTEXPR const int  max_exponent = __DBL_MAX_EXP__;
+    static _LIBCPP_CONSTEXPR const int  max_exponent10 = __DBL_MAX_10_EXP__;
+
+    static _LIBCPP_CONSTEXPR const bool has_infinity = true;
+    static _LIBCPP_CONSTEXPR const bool has_quiet_NaN = true;
+    static _LIBCPP_CONSTEXPR const bool has_signaling_NaN = true;
+    static _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = denorm_present;
+    static _LIBCPP_CONSTEXPR const bool has_denorm_loss = false;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT {return __builtin_huge_val();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT {return __builtin_nan("");}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT {return __builtin_nans("");}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT {return __DBL_DENORM_MIN__;}
+
+    static _LIBCPP_CONSTEXPR const bool is_iec559 = true;
+    static _LIBCPP_CONSTEXPR const bool is_bounded = true;
+    static _LIBCPP_CONSTEXPR const bool is_modulo = false;
+
+    static _LIBCPP_CONSTEXPR const bool traps = false;
+    static _LIBCPP_CONSTEXPR const bool tinyness_before = false;
+    static _LIBCPP_CONSTEXPR const float_round_style round_style = round_to_nearest;
+};
+
+template <>
+class __libcpp_numeric_limits<long double, true>
+{
+protected:
+    typedef long double type;
+
+    static _LIBCPP_CONSTEXPR const bool is_specialized = true;
+
+    static _LIBCPP_CONSTEXPR const bool is_signed = true;
+    static _LIBCPP_CONSTEXPR const int  digits = __LDBL_MANT_DIG__;
+    static _LIBCPP_CONSTEXPR const int  digits10 = __LDBL_DIG__;
+    static _LIBCPP_CONSTEXPR const int  max_digits10 = 2+(digits * 30103l)/100000l;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type min() _NOEXCEPT {return __LDBL_MIN__;}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type max() _NOEXCEPT {return __LDBL_MAX__;}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT {return -max();}
+
+    static _LIBCPP_CONSTEXPR const bool is_integer = false;
+    static _LIBCPP_CONSTEXPR const bool is_exact = false;
+    static _LIBCPP_CONSTEXPR const int  radix = __FLT_RADIX__;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT {return __LDBL_EPSILON__;}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT {return 0.5L;}
+
+    static _LIBCPP_CONSTEXPR const int  min_exponent = __LDBL_MIN_EXP__;
+    static _LIBCPP_CONSTEXPR const int  min_exponent10 = __LDBL_MIN_10_EXP__;
+    static _LIBCPP_CONSTEXPR const int  max_exponent = __LDBL_MAX_EXP__;
+    static _LIBCPP_CONSTEXPR const int  max_exponent10 = __LDBL_MAX_10_EXP__;
+
+    static _LIBCPP_CONSTEXPR const bool has_infinity = true;
+    static _LIBCPP_CONSTEXPR const bool has_quiet_NaN = true;
+    static _LIBCPP_CONSTEXPR const bool has_signaling_NaN = true;
+    static _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = denorm_present;
+    static _LIBCPP_CONSTEXPR const bool has_denorm_loss = false;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT {return __builtin_huge_vall();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT {return __builtin_nanl("");}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT {return __builtin_nansl("");}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT {return __LDBL_DENORM_MIN__;}
+
+#if (defined(__ppc__) || defined(__ppc64__))
+    static _LIBCPP_CONSTEXPR const bool is_iec559 = false;
+#else
+    static _LIBCPP_CONSTEXPR const bool is_iec559 = true;
+#endif
+    static _LIBCPP_CONSTEXPR const bool is_bounded = true;
+    static _LIBCPP_CONSTEXPR const bool is_modulo = false;
+
+    static _LIBCPP_CONSTEXPR const bool traps = false;
+    static _LIBCPP_CONSTEXPR const bool tinyness_before = false;
+    static _LIBCPP_CONSTEXPR const float_round_style round_style = round_to_nearest;
+};
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS numeric_limits
+    : private __libcpp_numeric_limits<typename remove_cv<_Tp>::type>
+{
+    typedef __libcpp_numeric_limits<typename remove_cv<_Tp>::type> __base;
+    typedef typename __base::type type;
+public:
+    static _LIBCPP_CONSTEXPR const bool is_specialized = __base::is_specialized;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type min() _NOEXCEPT {return __base::min();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type max() _NOEXCEPT {return __base::max();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT {return __base::lowest();}
+
+    static _LIBCPP_CONSTEXPR const int  digits = __base::digits;
+    static _LIBCPP_CONSTEXPR const int  digits10 = __base::digits10;
+    static _LIBCPP_CONSTEXPR const int  max_digits10 = __base::max_digits10;
+    static _LIBCPP_CONSTEXPR const bool is_signed = __base::is_signed;
+    static _LIBCPP_CONSTEXPR const bool is_integer = __base::is_integer;
+    static _LIBCPP_CONSTEXPR const bool is_exact = __base::is_exact;
+    static _LIBCPP_CONSTEXPR const int  radix = __base::radix;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT {return __base::epsilon();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT {return __base::round_error();}
+
+    static _LIBCPP_CONSTEXPR const int  min_exponent = __base::min_exponent;
+    static _LIBCPP_CONSTEXPR const int  min_exponent10 = __base::min_exponent10;
+    static _LIBCPP_CONSTEXPR const int  max_exponent = __base::max_exponent;
+    static _LIBCPP_CONSTEXPR const int  max_exponent10 = __base::max_exponent10;
+
+    static _LIBCPP_CONSTEXPR const bool has_infinity = __base::has_infinity;
+    static _LIBCPP_CONSTEXPR const bool has_quiet_NaN = __base::has_quiet_NaN;
+    static _LIBCPP_CONSTEXPR const bool has_signaling_NaN = __base::has_signaling_NaN;
+    static _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = __base::has_denorm;
+    static _LIBCPP_CONSTEXPR const bool has_denorm_loss = __base::has_denorm_loss;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT {return __base::infinity();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT {return __base::quiet_NaN();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT {return __base::signaling_NaN();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT {return __base::denorm_min();}
+
+    static _LIBCPP_CONSTEXPR const bool is_iec559 = __base::is_iec559;
+    static _LIBCPP_CONSTEXPR const bool is_bounded = __base::is_bounded;
+    static _LIBCPP_CONSTEXPR const bool is_modulo = __base::is_modulo;
+
+    static _LIBCPP_CONSTEXPR const bool traps = __base::traps;
+    static _LIBCPP_CONSTEXPR const bool tinyness_before = __base::tinyness_before;
+    static _LIBCPP_CONSTEXPR const float_round_style round_style = __base::round_style;
+};
+
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<_Tp>::is_specialized;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<_Tp>::digits;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<_Tp>::digits10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<_Tp>::max_digits10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<_Tp>::is_signed;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<_Tp>::is_integer;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<_Tp>::is_exact;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<_Tp>::radix;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<_Tp>::min_exponent;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<_Tp>::min_exponent10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<_Tp>::max_exponent;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<_Tp>::max_exponent10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<_Tp>::has_infinity;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<_Tp>::has_quiet_NaN;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<_Tp>::has_signaling_NaN;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const float_denorm_style numeric_limits<_Tp>::has_denorm;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<_Tp>::has_denorm_loss;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<_Tp>::is_iec559;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<_Tp>::is_bounded;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<_Tp>::is_modulo;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<_Tp>::traps;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<_Tp>::tinyness_before;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const float_round_style numeric_limits<_Tp>::round_style;
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS numeric_limits<const _Tp>
+    : private numeric_limits<_Tp>
+{
+    typedef numeric_limits<_Tp> __base;
+    typedef _Tp type;
+public:
+    static _LIBCPP_CONSTEXPR const bool is_specialized = __base::is_specialized;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type min() _NOEXCEPT {return __base::min();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type max() _NOEXCEPT {return __base::max();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT {return __base::lowest();}
+
+    static _LIBCPP_CONSTEXPR const int  digits = __base::digits;
+    static _LIBCPP_CONSTEXPR const int  digits10 = __base::digits10;
+    static _LIBCPP_CONSTEXPR const int  max_digits10 = __base::max_digits10;
+    static _LIBCPP_CONSTEXPR const bool is_signed = __base::is_signed;
+    static _LIBCPP_CONSTEXPR const bool is_integer = __base::is_integer;
+    static _LIBCPP_CONSTEXPR const bool is_exact = __base::is_exact;
+    static _LIBCPP_CONSTEXPR const int  radix = __base::radix;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT {return __base::epsilon();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT {return __base::round_error();}
+
+    static _LIBCPP_CONSTEXPR const int  min_exponent = __base::min_exponent;
+    static _LIBCPP_CONSTEXPR const int  min_exponent10 = __base::min_exponent10;
+    static _LIBCPP_CONSTEXPR const int  max_exponent = __base::max_exponent;
+    static _LIBCPP_CONSTEXPR const int  max_exponent10 = __base::max_exponent10;
+
+    static _LIBCPP_CONSTEXPR const bool has_infinity = __base::has_infinity;
+    static _LIBCPP_CONSTEXPR const bool has_quiet_NaN = __base::has_quiet_NaN;
+    static _LIBCPP_CONSTEXPR const bool has_signaling_NaN = __base::has_signaling_NaN;
+    static _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = __base::has_denorm;
+    static _LIBCPP_CONSTEXPR const bool has_denorm_loss = __base::has_denorm_loss;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT {return __base::infinity();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT {return __base::quiet_NaN();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT {return __base::signaling_NaN();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT {return __base::denorm_min();}
+
+    static _LIBCPP_CONSTEXPR const bool is_iec559 = __base::is_iec559;
+    static _LIBCPP_CONSTEXPR const bool is_bounded = __base::is_bounded;
+    static _LIBCPP_CONSTEXPR const bool is_modulo = __base::is_modulo;
+
+    static _LIBCPP_CONSTEXPR const bool traps = __base::traps;
+    static _LIBCPP_CONSTEXPR const bool tinyness_before = __base::tinyness_before;
+    static _LIBCPP_CONSTEXPR const float_round_style round_style = __base::round_style;
+};
+
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const _Tp>::is_specialized;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const _Tp>::digits;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const _Tp>::digits10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const _Tp>::max_digits10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const _Tp>::is_signed;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const _Tp>::is_integer;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const _Tp>::is_exact;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const _Tp>::radix;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const _Tp>::min_exponent;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const _Tp>::min_exponent10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const _Tp>::max_exponent;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const _Tp>::max_exponent10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const _Tp>::has_infinity;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const _Tp>::has_quiet_NaN;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const _Tp>::has_signaling_NaN;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const float_denorm_style numeric_limits<const _Tp>::has_denorm;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const _Tp>::has_denorm_loss;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const _Tp>::is_iec559;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const _Tp>::is_bounded;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const _Tp>::is_modulo;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const _Tp>::traps;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const _Tp>::tinyness_before;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const float_round_style numeric_limits<const _Tp>::round_style;
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS numeric_limits<volatile _Tp>
+    : private numeric_limits<_Tp>
+{
+    typedef numeric_limits<_Tp> __base;
+    typedef _Tp type;
+public:
+    static _LIBCPP_CONSTEXPR const bool is_specialized = __base::is_specialized;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type min() _NOEXCEPT {return __base::min();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type max() _NOEXCEPT {return __base::max();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT {return __base::lowest();}
+
+    static _LIBCPP_CONSTEXPR const int  digits = __base::digits;
+    static _LIBCPP_CONSTEXPR const int  digits10 = __base::digits10;
+    static _LIBCPP_CONSTEXPR const int  max_digits10 = __base::max_digits10;
+    static _LIBCPP_CONSTEXPR const bool is_signed = __base::is_signed;
+    static _LIBCPP_CONSTEXPR const bool is_integer = __base::is_integer;
+    static _LIBCPP_CONSTEXPR const bool is_exact = __base::is_exact;
+    static _LIBCPP_CONSTEXPR const int  radix = __base::radix;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT {return __base::epsilon();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT {return __base::round_error();}
+
+    static _LIBCPP_CONSTEXPR const int  min_exponent = __base::min_exponent;
+    static _LIBCPP_CONSTEXPR const int  min_exponent10 = __base::min_exponent10;
+    static _LIBCPP_CONSTEXPR const int  max_exponent = __base::max_exponent;
+    static _LIBCPP_CONSTEXPR const int  max_exponent10 = __base::max_exponent10;
+
+    static _LIBCPP_CONSTEXPR const bool has_infinity = __base::has_infinity;
+    static _LIBCPP_CONSTEXPR const bool has_quiet_NaN = __base::has_quiet_NaN;
+    static _LIBCPP_CONSTEXPR const bool has_signaling_NaN = __base::has_signaling_NaN;
+    static _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = __base::has_denorm;
+    static _LIBCPP_CONSTEXPR const bool has_denorm_loss = __base::has_denorm_loss;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT {return __base::infinity();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT {return __base::quiet_NaN();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT {return __base::signaling_NaN();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT {return __base::denorm_min();}
+
+    static _LIBCPP_CONSTEXPR const bool is_iec559 = __base::is_iec559;
+    static _LIBCPP_CONSTEXPR const bool is_bounded = __base::is_bounded;
+    static _LIBCPP_CONSTEXPR const bool is_modulo = __base::is_modulo;
+
+    static _LIBCPP_CONSTEXPR const bool traps = __base::traps;
+    static _LIBCPP_CONSTEXPR const bool tinyness_before = __base::tinyness_before;
+    static _LIBCPP_CONSTEXPR const float_round_style round_style = __base::round_style;
+};
+
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<volatile _Tp>::is_specialized;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<volatile _Tp>::digits;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<volatile _Tp>::digits10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<volatile _Tp>::max_digits10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<volatile _Tp>::is_signed;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<volatile _Tp>::is_integer;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<volatile _Tp>::is_exact;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<volatile _Tp>::radix;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<volatile _Tp>::min_exponent;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<volatile _Tp>::min_exponent10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<volatile _Tp>::max_exponent;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<volatile _Tp>::max_exponent10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<volatile _Tp>::has_infinity;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<volatile _Tp>::has_quiet_NaN;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<volatile _Tp>::has_signaling_NaN;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const float_denorm_style numeric_limits<volatile _Tp>::has_denorm;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<volatile _Tp>::has_denorm_loss;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<volatile _Tp>::is_iec559;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<volatile _Tp>::is_bounded;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<volatile _Tp>::is_modulo;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<volatile _Tp>::traps;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<volatile _Tp>::tinyness_before;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const float_round_style numeric_limits<volatile _Tp>::round_style;
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS numeric_limits<const volatile _Tp>
+    : private numeric_limits<_Tp>
+{
+    typedef numeric_limits<_Tp> __base;
+    typedef _Tp type;
+public:
+    static _LIBCPP_CONSTEXPR const bool is_specialized = __base::is_specialized;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type min() _NOEXCEPT {return __base::min();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type max() _NOEXCEPT {return __base::max();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type lowest() _NOEXCEPT {return __base::lowest();}
+
+    static _LIBCPP_CONSTEXPR const int  digits = __base::digits;
+    static _LIBCPP_CONSTEXPR const int  digits10 = __base::digits10;
+    static _LIBCPP_CONSTEXPR const int  max_digits10 = __base::max_digits10;
+    static _LIBCPP_CONSTEXPR const bool is_signed = __base::is_signed;
+    static _LIBCPP_CONSTEXPR const bool is_integer = __base::is_integer;
+    static _LIBCPP_CONSTEXPR const bool is_exact = __base::is_exact;
+    static _LIBCPP_CONSTEXPR const int  radix = __base::radix;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type epsilon() _NOEXCEPT {return __base::epsilon();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type round_error() _NOEXCEPT {return __base::round_error();}
+
+    static _LIBCPP_CONSTEXPR const int  min_exponent = __base::min_exponent;
+    static _LIBCPP_CONSTEXPR const int  min_exponent10 = __base::min_exponent10;
+    static _LIBCPP_CONSTEXPR const int  max_exponent = __base::max_exponent;
+    static _LIBCPP_CONSTEXPR const int  max_exponent10 = __base::max_exponent10;
+
+    static _LIBCPP_CONSTEXPR const bool has_infinity = __base::has_infinity;
+    static _LIBCPP_CONSTEXPR const bool has_quiet_NaN = __base::has_quiet_NaN;
+    static _LIBCPP_CONSTEXPR const bool has_signaling_NaN = __base::has_signaling_NaN;
+    static _LIBCPP_CONSTEXPR const float_denorm_style has_denorm = __base::has_denorm;
+    static _LIBCPP_CONSTEXPR const bool has_denorm_loss = __base::has_denorm_loss;
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type infinity() _NOEXCEPT {return __base::infinity();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type quiet_NaN() _NOEXCEPT {return __base::quiet_NaN();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type signaling_NaN() _NOEXCEPT {return __base::signaling_NaN();}
+    _LIBCPP_INLINE_VISIBILITY static _LIBCPP_CONSTEXPR type denorm_min() _NOEXCEPT {return __base::denorm_min();}
+
+    static _LIBCPP_CONSTEXPR const bool is_iec559 = __base::is_iec559;
+    static _LIBCPP_CONSTEXPR const bool is_bounded = __base::is_bounded;
+    static _LIBCPP_CONSTEXPR const bool is_modulo = __base::is_modulo;
+
+    static _LIBCPP_CONSTEXPR const bool traps = __base::traps;
+    static _LIBCPP_CONSTEXPR const bool tinyness_before = __base::tinyness_before;
+    static _LIBCPP_CONSTEXPR const float_round_style round_style = __base::round_style;
+};
+
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const volatile _Tp>::is_specialized;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const volatile _Tp>::digits;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const volatile _Tp>::digits10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const volatile _Tp>::max_digits10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const volatile _Tp>::is_signed;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const volatile _Tp>::is_integer;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const volatile _Tp>::is_exact;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const volatile _Tp>::radix;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const volatile _Tp>::min_exponent;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const volatile _Tp>::min_exponent10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const volatile _Tp>::max_exponent;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const int numeric_limits<const volatile _Tp>::max_exponent10;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const volatile _Tp>::has_infinity;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const volatile _Tp>::has_quiet_NaN;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const volatile _Tp>::has_signaling_NaN;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const float_denorm_style numeric_limits<const volatile _Tp>::has_denorm;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const volatile _Tp>::has_denorm_loss;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const volatile _Tp>::is_iec559;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const volatile _Tp>::is_bounded;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const volatile _Tp>::is_modulo;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const volatile _Tp>::traps;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const bool numeric_limits<const volatile _Tp>::tinyness_before;
+template <class _Tp>
+    _LIBCPP_CONSTEXPR const float_round_style numeric_limits<const volatile _Tp>::round_style;
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_LIMITS
diff --git a/contrib/libs/cxxsupp/libcxx/include/limits.h b/contrib/libs/cxxsupp/libcxx/include/limits.h
new file mode 100644
index 00000000000..ebbfa6aa168
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/limits.h
@@ -0,0 +1,68 @@
+// -*- C++ -*-
+//===--------------------------- limits.h ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_LIMITS_H
+#define _LIBCPP_LIMITS_H
+
+/*
+    limits.h synopsis
+
+Macros:
+
+    CHAR_BIT
+    SCHAR_MIN
+    SCHAR_MAX
+    UCHAR_MAX
+    CHAR_MIN
+    CHAR_MAX
+    MB_LEN_MAX
+    SHRT_MIN
+    SHRT_MAX
+    USHRT_MAX
+    INT_MIN
+    INT_MAX
+    UINT_MAX
+    LONG_MIN
+    LONG_MAX
+    ULONG_MAX
+    LLONG_MIN   // C99
+    LLONG_MAX   // C99
+    ULLONG_MAX  // C99
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifndef __GNUC__
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_MSVC_INCLUDE(limits.h)
+#else
+#include_next <limits.h>
+#endif
+#else
+// GCC header limits.h recursively includes itself through another header called
+// syslimits.h for some reason. This setup breaks down if we directly
+// #include_next GCC's limits.h (reasons not entirely clear to me). Therefore,
+// we manually re-create the necessary include sequence below:
+
+// Get the system limits.h defines (force recurse into the next level)
+#define _GCC_LIMITS_H_
+#define _GCC_NEXT_LIMITS_H
+#include_next <limits.h>
+
+// Get the ISO C defines
+#undef _GCC_LIMITS_H_
+#include_next <limits.h>
+#endif // __GNUC__
+
+#endif // _LIBCPP_LIMITS_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/list b/contrib/libs/cxxsupp/libcxx/include/list
new file mode 100644
index 00000000000..71406c6743d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/list
@@ -0,0 +1,2494 @@
+// -*- C++ -*-
+//===---------------------------- list ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_LIST
+#define _LIBCPP_LIST
+
+/*
+    list synopsis
+
+namespace std
+{
+
+template <class T, class Alloc = allocator<T> >
+class list
+{
+public:
+
+    // types:
+    typedef T value_type;
+    typedef Alloc allocator_type;
+    typedef typename allocator_type::reference reference;
+    typedef typename allocator_type::const_reference const_reference;
+    typedef typename allocator_type::pointer pointer;
+    typedef typename allocator_type::const_pointer const_pointer;
+    typedef implementation-defined iterator;
+    typedef implementation-defined const_iterator;
+    typedef implementation-defined size_type;
+    typedef implementation-defined difference_type;
+    typedef reverse_iterator<iterator> reverse_iterator;
+    typedef reverse_iterator<const_iterator> const_reverse_iterator;
+
+    list()
+        noexcept(is_nothrow_default_constructible<allocator_type>::value);
+    explicit list(const allocator_type& a);
+    explicit list(size_type n);
+    explicit list(size_type n, const allocator_type& a); // C++14
+    list(size_type n, const value_type& value);
+    list(size_type n, const value_type& value, const allocator_type& a);
+    template <class Iter>
+        list(Iter first, Iter last);
+    template <class Iter>
+        list(Iter first, Iter last, const allocator_type& a);
+    list(const list& x);
+    list(const list&, const allocator_type& a);
+    list(list&& x)
+        noexcept(is_nothrow_move_constructible<allocator_type>::value);
+    list(list&&, const allocator_type& a);
+    list(initializer_list<value_type>);
+    list(initializer_list<value_type>, const allocator_type& a);
+
+    ~list();
+
+    list& operator=(const list& x);
+    list& operator=(list&& x)
+        noexcept(
+             allocator_type::propagate_on_container_move_assignment::value &&
+             is_nothrow_move_assignable<allocator_type>::value);
+    list& operator=(initializer_list<value_type>);
+    template <class Iter>
+        void assign(Iter first, Iter last);
+    void assign(size_type n, const value_type& t);
+    void assign(initializer_list<value_type>);
+
+    allocator_type get_allocator() const noexcept;
+
+    iterator begin() noexcept;
+    const_iterator begin() const noexcept;
+    iterator end() noexcept;
+    const_iterator end() const noexcept;
+    reverse_iterator rbegin() noexcept;
+    const_reverse_iterator rbegin() const noexcept;
+    reverse_iterator rend() noexcept;
+    const_reverse_iterator rend() const noexcept;
+    const_iterator cbegin() const noexcept;
+    const_iterator cend() const noexcept;
+    const_reverse_iterator crbegin() const noexcept;
+    const_reverse_iterator crend() const noexcept;
+
+    reference front();
+    const_reference front() const;
+    reference back();
+    const_reference back() const;
+
+    bool empty() const noexcept;
+    size_type size() const noexcept;
+    size_type max_size() const noexcept;
+
+    template <class... Args>
+        reference emplace_front(Args&&... args); // reference in C++17
+    void pop_front();
+    template <class... Args>
+        reference emplace_back(Args&&... args);  // reference in C++17
+    void pop_back();
+    void push_front(const value_type& x);
+    void push_front(value_type&& x);
+    void push_back(const value_type& x);
+    void push_back(value_type&& x);
+    template <class... Args>
+        iterator emplace(const_iterator position, Args&&... args);
+    iterator insert(const_iterator position, const value_type& x);
+    iterator insert(const_iterator position, value_type&& x);
+    iterator insert(const_iterator position, size_type n, const value_type& x);
+    template <class Iter>
+        iterator insert(const_iterator position, Iter first, Iter last);
+    iterator insert(const_iterator position, initializer_list<value_type> il);
+
+    iterator erase(const_iterator position);
+    iterator erase(const_iterator position, const_iterator last);
+
+    void resize(size_type sz);
+    void resize(size_type sz, const value_type& c);
+
+    void swap(list&)
+        noexcept(allocator_traits<allocator_type>::is_always_equal::value);  // C++17
+    void clear() noexcept;
+
+    void splice(const_iterator position, list& x);
+    void splice(const_iterator position, list&& x);
+    void splice(const_iterator position, list& x, const_iterator i);
+    void splice(const_iterator position, list&& x, const_iterator i);
+    void splice(const_iterator position, list& x, const_iterator first,
+                                                  const_iterator last);
+    void splice(const_iterator position, list&& x, const_iterator first,
+                                                  const_iterator last);
+
+    size_type remove(const value_type& value);       // void before C++20
+    template <class Pred>
+      size_type remove_if(Pred pred);                // void before C++20
+    size_type unique();                              // void before C++20
+    template <class BinaryPredicate>
+      size_type unique(BinaryPredicate binary_pred); // void before C++20
+    void merge(list& x);
+    void merge(list&& x);
+    template <class Compare>
+        void merge(list& x, Compare comp);
+    template <class Compare>
+        void merge(list&& x, Compare comp);
+    void sort();
+    template <class Compare>
+        void sort(Compare comp);
+    void reverse() noexcept;
+};
+
+
+template <class InputIterator, class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
+    list(InputIterator, InputIterator, Allocator = Allocator())
+    -> list<typename iterator_traits<InputIterator>::value_type, Allocator>;  // C++17
+
+template <class T, class Alloc>
+    bool operator==(const list<T,Alloc>& x, const list<T,Alloc>& y);
+template <class T, class Alloc>
+    bool operator< (const list<T,Alloc>& x, const list<T,Alloc>& y);
+template <class T, class Alloc>
+    bool operator!=(const list<T,Alloc>& x, const list<T,Alloc>& y);
+template <class T, class Alloc>
+    bool operator> (const list<T,Alloc>& x, const list<T,Alloc>& y);
+template <class T, class Alloc>
+    bool operator>=(const list<T,Alloc>& x, const list<T,Alloc>& y);
+template <class T, class Alloc>
+    bool operator<=(const list<T,Alloc>& x, const list<T,Alloc>& y);
+
+template <class T, class Alloc>
+    void swap(list<T,Alloc>& x, list<T,Alloc>& y)
+         noexcept(noexcept(x.swap(y)));
+
+template <class T, class Allocator, class U>
+    typename list<T, Allocator>::size_type
+    erase(list<T, Allocator>& c, const U& value);       // C++20
+template <class T, class Allocator, class Predicate>
+    typename list<T, Allocator>::size_type
+    erase_if(list<T, Allocator>& c, Predicate pred);    // C++20
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__utility/forward.h>
+#include <algorithm>
+#include <initializer_list>
+#include <iterator>
+#include <limits>
+#include <memory>
+#include <type_traits>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class _VoidPtr> struct __list_node;
+template <class _Tp, class _VoidPtr> struct __list_node_base;
+
+template <class _Tp, class _VoidPtr>
+struct __list_node_pointer_traits {
+  typedef typename __rebind_pointer<_VoidPtr, __list_node<_Tp, _VoidPtr> >::type
+        __node_pointer;
+  typedef typename __rebind_pointer<_VoidPtr, __list_node_base<_Tp, _VoidPtr> >::type
+        __base_pointer;
+
+#if defined(_LIBCPP_ABI_LIST_REMOVE_NODE_POINTER_UB)
+  typedef __base_pointer __link_pointer;
+#else
+  typedef typename conditional<
+          is_pointer<_VoidPtr>::value,
+          __base_pointer,
+          __node_pointer
+  >::type __link_pointer;
+#endif
+
+  typedef typename conditional<
+          is_same<__link_pointer, __node_pointer>::value,
+          __base_pointer,
+          __node_pointer
+  >::type __non_link_pointer;
+
+  static _LIBCPP_INLINE_VISIBILITY
+  __link_pointer __unsafe_link_pointer_cast(__link_pointer __p) {
+      return __p;
+  }
+
+  static _LIBCPP_INLINE_VISIBILITY
+  __link_pointer __unsafe_link_pointer_cast(__non_link_pointer __p) {
+      return static_cast<__link_pointer>(static_cast<_VoidPtr>(__p));
+  }
+
+};
+
+template <class _Tp, class _VoidPtr>
+struct __list_node_base
+{
+    typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
+    typedef typename _NodeTraits::__node_pointer __node_pointer;
+    typedef typename _NodeTraits::__base_pointer __base_pointer;
+    typedef typename _NodeTraits::__link_pointer __link_pointer;
+
+    __link_pointer __prev_;
+    __link_pointer __next_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_node_base() : __prev_(_NodeTraits::__unsafe_link_pointer_cast(__self())),
+                         __next_(_NodeTraits::__unsafe_link_pointer_cast(__self())) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __base_pointer __self() {
+        return pointer_traits<__base_pointer>::pointer_to(*this);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __node_pointer __as_node() {
+        return static_cast<__node_pointer>(__self());
+    }
+};
+
+template <class _Tp, class _VoidPtr>
+struct _LIBCPP_STANDALONE_DEBUG __list_node
+    : public __list_node_base<_Tp, _VoidPtr>
+{
+    _Tp __value_;
+
+    typedef __list_node_base<_Tp, _VoidPtr> __base;
+    typedef typename __base::__link_pointer __link_pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __link_pointer __as_link() {
+        return static_cast<__link_pointer>(__base::__self());
+    }
+};
+
+template <class _Tp, class _Alloc = allocator<_Tp> > class _LIBCPP_TEMPLATE_VIS list;
+template <class _Tp, class _Alloc> class __list_imp;
+template <class _Tp, class _VoidPtr> class _LIBCPP_TEMPLATE_VIS __list_const_iterator;
+
+template <class _Tp, class _VoidPtr>
+class _LIBCPP_TEMPLATE_VIS __list_iterator
+{
+    typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
+    typedef typename _NodeTraits::__link_pointer __link_pointer;
+
+    __link_pointer __ptr_;
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __list_iterator(__link_pointer __p, const void* __c) _NOEXCEPT
+        : __ptr_(__p)
+    {
+        __get_db()->__insert_ic(this, __c);
+    }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __list_iterator(__link_pointer __p) _NOEXCEPT : __ptr_(__p) {}
+#endif
+
+
+
+    template<class, class> friend class list;
+    template<class, class> friend class __list_imp;
+    template<class, class> friend class __list_const_iterator;
+public:
+    typedef bidirectional_iterator_tag       iterator_category;
+    typedef _Tp                              value_type;
+    typedef value_type&                      reference;
+    typedef typename __rebind_pointer<_VoidPtr, value_type>::type pointer;
+    typedef typename pointer_traits<pointer>::difference_type difference_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator() _NOEXCEPT : __ptr_(nullptr)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_i(this);
+#endif
+    }
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator(const __list_iterator& __p)
+        : __ptr_(__p.__ptr_)
+    {
+        __get_db()->__iterator_copy(this, _VSTD::addressof(__p));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~__list_iterator()
+    {
+        __get_db()->__erase_i(this);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator& operator=(const __list_iterator& __p)
+    {
+        if (this != _VSTD::addressof(__p))
+        {
+            __get_db()->__iterator_copy(this, _VSTD::addressof(__p));
+            __ptr_ = __p.__ptr_;
+        }
+        return *this;
+    }
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to dereference a non-dereferenceable list::iterator");
+#endif
+        return __ptr_->__as_node()->__value_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to dereference a non-dereferenceable list::iterator");
+#endif
+        return pointer_traits<pointer>::pointer_to(__ptr_->__as_node()->__value_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator& operator++()
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to increment a non-incrementable list::iterator");
+#endif
+        __ptr_ = __ptr_->__next_;
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator operator++(int) {__list_iterator __t(*this); ++(*this); return __t;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator& operator--()
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__decrementable(this),
+                       "Attempted to decrement a non-decrementable list::iterator");
+#endif
+        __ptr_ = __ptr_->__prev_;
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __list_iterator operator--(int) {__list_iterator __t(*this); --(*this); return __t;}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __list_iterator& __x, const __list_iterator& __y)
+    {
+        return __x.__ptr_ == __y.__ptr_;
+    }
+    friend _LIBCPP_INLINE_VISIBILITY
+     bool operator!=(const __list_iterator& __x, const __list_iterator& __y)
+        {return !(__x == __y);}
+};
+
+template <class _Tp, class _VoidPtr>
+class _LIBCPP_TEMPLATE_VIS __list_const_iterator
+{
+    typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
+    typedef typename _NodeTraits::__link_pointer __link_pointer;
+
+    __link_pointer __ptr_;
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __list_const_iterator(__link_pointer __p, const void* __c) _NOEXCEPT
+        : __ptr_(__p)
+    {
+        __get_db()->__insert_ic(this, __c);
+    }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __list_const_iterator(__link_pointer __p) _NOEXCEPT : __ptr_(__p) {}
+#endif
+
+    template<class, class> friend class list;
+    template<class, class> friend class __list_imp;
+public:
+    typedef bidirectional_iterator_tag       iterator_category;
+    typedef _Tp                              value_type;
+    typedef const value_type&                reference;
+    typedef typename __rebind_pointer<_VoidPtr, const value_type>::type pointer;
+    typedef typename pointer_traits<pointer>::difference_type difference_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator() _NOEXCEPT : __ptr_(nullptr)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_i(this);
+#endif
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator(const __list_iterator<_Tp, _VoidPtr>& __p) _NOEXCEPT
+        : __ptr_(__p.__ptr_)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__iterator_copy(this, _VSTD::addressof(__p));
+#endif
+    }
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator(const __list_const_iterator& __p)
+        : __ptr_(__p.__ptr_)
+    {
+        __get_db()->__iterator_copy(this, _VSTD::addressof(__p));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~__list_const_iterator()
+    {
+        __get_db()->__erase_i(this);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator& operator=(const __list_const_iterator& __p)
+    {
+        if (this != &__p)
+        {
+            __get_db()->__iterator_copy(this, &__p);
+            __ptr_ = __p.__ptr_;
+        }
+        return *this;
+    }
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to dereference a non-dereferenceable list::const_iterator");
+#endif
+        return __ptr_->__as_node()->__value_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to dereference a non-dereferenceable list::const_iterator");
+#endif
+        return pointer_traits<pointer>::pointer_to(__ptr_->__as_node()->__value_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator& operator++()
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
+                       "Attempted to increment a non-incrementable list::const_iterator");
+#endif
+        __ptr_ = __ptr_->__next_;
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator operator++(int) {__list_const_iterator __t(*this); ++(*this); return __t;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator& operator--()
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__decrementable(this),
+                       "Attempted to decrement a non-decrementable list::const_iterator");
+#endif
+        __ptr_ = __ptr_->__prev_;
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    __list_const_iterator operator--(int) {__list_const_iterator __t(*this); --(*this); return __t;}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __list_const_iterator& __x, const __list_const_iterator& __y)
+    {
+        return __x.__ptr_ == __y.__ptr_;
+    }
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __list_const_iterator& __x, const __list_const_iterator& __y)
+        {return !(__x == __y);}
+};
+
+template <class _Tp, class _Alloc>
+class __list_imp
+{
+    __list_imp(const __list_imp&);
+    __list_imp& operator=(const __list_imp&);
+public:
+    typedef _Alloc                                                  allocator_type;
+    typedef allocator_traits<allocator_type>                        __alloc_traits;
+    typedef typename __alloc_traits::size_type                      size_type;
+protected:
+    typedef _Tp                                                     value_type;
+    typedef typename __alloc_traits::void_pointer                   __void_pointer;
+    typedef __list_iterator<value_type, __void_pointer>             iterator;
+    typedef __list_const_iterator<value_type, __void_pointer>       const_iterator;
+    typedef __list_node_base<value_type, __void_pointer>            __node_base;
+    typedef __list_node<value_type, __void_pointer>                 __node;
+    typedef typename __rebind_alloc_helper<__alloc_traits, __node>::type __node_allocator;
+    typedef allocator_traits<__node_allocator>                       __node_alloc_traits;
+    typedef typename __node_alloc_traits::pointer                    __node_pointer;
+    typedef typename __node_alloc_traits::pointer                    __node_const_pointer;
+    typedef __list_node_pointer_traits<value_type, __void_pointer> __node_pointer_traits;
+    typedef typename __node_pointer_traits::__link_pointer __link_pointer;
+    typedef __link_pointer __link_const_pointer;
+    typedef typename __alloc_traits::pointer                         pointer;
+    typedef typename __alloc_traits::const_pointer                   const_pointer;
+    typedef typename __alloc_traits::difference_type                 difference_type;
+
+    typedef typename __rebind_alloc_helper<__alloc_traits, __node_base>::type __node_base_allocator;
+    typedef typename allocator_traits<__node_base_allocator>::pointer __node_base_pointer;
+    static_assert((!is_same<allocator_type, __node_allocator>::value),
+                  "internal allocator type must differ from user-specified "
+                  "type; otherwise overload resolution breaks");
+
+    __node_base __end_;
+    __compressed_pair<size_type, __node_allocator> __size_alloc_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __link_pointer __end_as_link() const _NOEXCEPT {
+        return __node_pointer_traits::__unsafe_link_pointer_cast(
+                const_cast<__node_base&>(__end_).__self());
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+          size_type& __sz() _NOEXCEPT {return __size_alloc_.first();}
+    _LIBCPP_INLINE_VISIBILITY
+    const size_type& __sz() const _NOEXCEPT
+        {return __size_alloc_.first();}
+    _LIBCPP_INLINE_VISIBILITY
+          __node_allocator& __node_alloc() _NOEXCEPT
+          {return __size_alloc_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    const __node_allocator& __node_alloc() const _NOEXCEPT
+        {return __size_alloc_.second();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type __node_alloc_max_size() const _NOEXCEPT {
+        return __node_alloc_traits::max_size(__node_alloc());
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    static void __unlink_nodes(__link_pointer __f, __link_pointer __l) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __list_imp()
+        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    __list_imp(const allocator_type& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    __list_imp(const __node_allocator& __a);
+#ifndef _LIBCPP_CXX03_LANG
+    __list_imp(__node_allocator&& __a) _NOEXCEPT;
+#endif
+    ~__list_imp();
+    void clear() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT {return __sz() == 0;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator begin() _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        return iterator(__end_.__next_, this);
+#else
+        return iterator(__end_.__next_);
+#endif
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const  _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        return const_iterator(__end_.__next_, this);
+#else
+        return const_iterator(__end_.__next_);
+#endif
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    iterator end() _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        return iterator(__end_as_link(), this);
+#else
+        return iterator(__end_as_link());
+#endif
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end() const _NOEXCEPT
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        return const_iterator(__end_as_link(), this);
+#else
+        return const_iterator(__end_as_link());
+#endif
+    }
+
+    void swap(__list_imp& __c)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT;
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<allocator_type>::value);
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __list_imp& __c)
+        {__copy_assign_alloc(__c, integral_constant<bool,
+                      __node_alloc_traits::propagate_on_container_copy_assignment::value>());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__list_imp& __c)
+        _NOEXCEPT_(
+            !__node_alloc_traits::propagate_on_container_move_assignment::value ||
+            is_nothrow_move_assignable<__node_allocator>::value)
+        {__move_assign_alloc(__c, integral_constant<bool,
+                      __node_alloc_traits::propagate_on_container_move_assignment::value>());}
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __list_imp& __c, true_type)
+        {
+            if (__node_alloc() != __c.__node_alloc())
+                clear();
+            __node_alloc() = __c.__node_alloc();
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __list_imp&, false_type)
+        {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__list_imp& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value)
+        {
+            __node_alloc() = _VSTD::move(__c.__node_alloc());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__list_imp&, false_type)
+        _NOEXCEPT
+        {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __invalidate_all_iterators() {
+#if _LIBCPP_DEBUG_LEVEL == 2
+      __get_db()->__invalidate_all(this);
+#endif
+    }
+};
+
+// Unlink nodes [__f, __l]
+template <class _Tp, class _Alloc>
+inline
+void
+__list_imp<_Tp, _Alloc>::__unlink_nodes(__link_pointer __f, __link_pointer __l)
+    _NOEXCEPT
+{
+    __f->__prev_->__next_ = __l->__next_;
+    __l->__next_->__prev_ = __f->__prev_;
+}
+
+template <class _Tp, class _Alloc>
+inline
+__list_imp<_Tp, _Alloc>::__list_imp()
+        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)
+    : __size_alloc_(0, __default_init_tag())
+{
+}
+
+template <class _Tp, class _Alloc>
+inline
+__list_imp<_Tp, _Alloc>::__list_imp(const allocator_type& __a)
+    : __size_alloc_(0, __node_allocator(__a))
+{
+}
+
+template <class _Tp, class _Alloc>
+inline __list_imp<_Tp, _Alloc>::__list_imp(const __node_allocator& __a)
+    : __size_alloc_(0, __a) {}
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp, class _Alloc>
+inline __list_imp<_Tp, _Alloc>::__list_imp(__node_allocator&& __a) _NOEXCEPT
+    : __size_alloc_(0, _VSTD::move(__a)) {}
+#endif
+
+template <class _Tp, class _Alloc>
+__list_imp<_Tp, _Alloc>::~__list_imp() {
+  clear();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__erase_c(this);
+#endif
+}
+
+template <class _Tp, class _Alloc>
+void
+__list_imp<_Tp, _Alloc>::clear() _NOEXCEPT
+{
+    if (!empty())
+    {
+        __node_allocator& __na = __node_alloc();
+        __link_pointer __f = __end_.__next_;
+        __link_pointer __l = __end_as_link();
+        __unlink_nodes(__f, __l->__prev_);
+        __sz() = 0;
+        while (__f != __l)
+        {
+            __node_pointer __np = __f->__as_node();
+            __f = __f->__next_;
+            __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
+            __node_alloc_traits::deallocate(__na, __np, 1);
+        }
+        __invalidate_all_iterators();
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+__list_imp<_Tp, _Alloc>::swap(__list_imp& __c)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<allocator_type>::value)
+#endif
+{
+    _LIBCPP_ASSERT(__alloc_traits::propagate_on_container_swap::value ||
+                   this->__node_alloc() == __c.__node_alloc(),
+                   "list::swap: Either propagate_on_container_swap must be true"
+                   " or the allocators must compare equal");
+    using _VSTD::swap;
+    _VSTD::__swap_allocator(__node_alloc(), __c.__node_alloc());
+    swap(__sz(), __c.__sz());
+    swap(__end_, __c.__end_);
+    if (__sz() == 0)
+        __end_.__next_ = __end_.__prev_ = __end_as_link();
+    else
+        __end_.__prev_->__next_ = __end_.__next_->__prev_ = __end_as_link();
+    if (__c.__sz() == 0)
+        __c.__end_.__next_ = __c.__end_.__prev_ = __c.__end_as_link();
+    else
+        __c.__end_.__prev_->__next_ = __c.__end_.__next_->__prev_ = __c.__end_as_link();
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __libcpp_db* __db = __get_db();
+    __c_node* __cn1 = __db->__find_c_and_lock(this);
+    __c_node* __cn2 = __db->__find_c(&__c);
+    _VSTD::swap(__cn1->beg_, __cn2->beg_);
+    _VSTD::swap(__cn1->end_, __cn2->end_);
+    _VSTD::swap(__cn1->cap_, __cn2->cap_);
+    for (__i_node** __p = __cn1->end_; __p != __cn1->beg_;)
+    {
+        --__p;
+        const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);
+        if (__i->__ptr_ == __c.__end_as_link())
+        {
+            __cn2->__add(*__p);
+            if (--__cn1->end_ != __p)
+                _VSTD::memmove(__p, __p+1, (__cn1->end_ - __p)*sizeof(__i_node*));
+        }
+        else
+            (*__p)->__c_ = __cn1;
+    }
+    for (__i_node** __p = __cn2->end_; __p != __cn2->beg_;)
+    {
+        --__p;
+        const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);
+        if (__i->__ptr_ == __end_as_link())
+        {
+            __cn1->__add(*__p);
+            if (--__cn2->end_ != __p)
+                _VSTD::memmove(__p, __p+1, (__cn2->end_ - __p)*sizeof(__i_node*));
+        }
+        else
+            (*__p)->__c_ = __cn2;
+    }
+    __db->unlock();
+#endif
+}
+
+template <class _Tp, class _Alloc /*= allocator<_Tp>*/>
+class _LIBCPP_TEMPLATE_VIS list
+    : private __list_imp<_Tp, _Alloc>
+{
+    typedef __list_imp<_Tp, _Alloc> base;
+    typedef typename base::__node              __node;
+    typedef typename base::__node_allocator    __node_allocator;
+    typedef typename base::__node_pointer      __node_pointer;
+    typedef typename base::__node_alloc_traits __node_alloc_traits;
+    typedef typename base::__node_base         __node_base;
+    typedef typename base::__node_base_pointer __node_base_pointer;
+    typedef typename base::__link_pointer __link_pointer;
+
+public:
+    typedef _Tp                                      value_type;
+    typedef _Alloc                                   allocator_type;
+    static_assert((is_same<value_type, typename allocator_type::value_type>::value),
+                  "Invalid allocator::value_type");
+    typedef value_type&                              reference;
+    typedef const value_type&                        const_reference;
+    typedef typename base::pointer                   pointer;
+    typedef typename base::const_pointer             const_pointer;
+    typedef typename base::size_type                 size_type;
+    typedef typename base::difference_type           difference_type;
+    typedef typename base::iterator                  iterator;
+    typedef typename base::const_iterator            const_iterator;
+    typedef _VSTD::reverse_iterator<iterator>         reverse_iterator;
+    typedef _VSTD::reverse_iterator<const_iterator>   const_reverse_iterator;
+#if _LIBCPP_STD_VER > 17
+    typedef size_type                                __remove_return_type;
+#else
+    typedef void                                     __remove_return_type;
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    list()
+        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_c(this);
+#endif
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    explicit list(const allocator_type& __a) : base(__a)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_c(this);
+#endif
+    }
+    explicit list(size_type __n);
+#if _LIBCPP_STD_VER > 11
+    explicit list(size_type __n, const allocator_type& __a);
+#endif
+    list(size_type __n, const value_type& __x);
+    list(size_type __n, const value_type& __x, const allocator_type& __a);
+    template <class _InpIter>
+        list(_InpIter __f, _InpIter __l,
+             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type* = 0);
+    template <class _InpIter>
+        list(_InpIter __f, _InpIter __l, const allocator_type& __a,
+             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type* = 0);
+
+    list(const list& __c);
+    list(const list& __c, const __identity_t<allocator_type>& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    list& operator=(const list& __c);
+#ifndef _LIBCPP_CXX03_LANG
+    list(initializer_list<value_type> __il);
+    list(initializer_list<value_type> __il, const allocator_type& __a);
+
+    _LIBCPP_INLINE_VISIBILITY
+    list(list&& __c)
+        _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    list(list&& __c, const __identity_t<allocator_type>& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    list& operator=(list&& __c)
+        _NOEXCEPT_(
+            __node_alloc_traits::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<__node_allocator>::value);
+
+    _LIBCPP_INLINE_VISIBILITY
+    list& operator=(initializer_list<value_type> __il)
+        {assign(__il.begin(), __il.end()); return *this;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void assign(initializer_list<value_type> __il)
+        {assign(__il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+
+    template <class _InpIter>
+        void assign(_InpIter __f, _InpIter __l,
+             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type* = 0);
+    void assign(size_type __n, const value_type& __x);
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT     {return base::__sz();}
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT         {return base::empty();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT
+        {
+            return _VSTD::min<size_type>(
+                base::__node_alloc_max_size(),
+                numeric_limits<difference_type >::max());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+          iterator begin() _NOEXCEPT        {return base::begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin()  const _NOEXCEPT {return base::begin();}
+    _LIBCPP_INLINE_VISIBILITY
+          iterator end() _NOEXCEPT          {return base::end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()    const _NOEXCEPT {return base::end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin() const _NOEXCEPT {return base::begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend()   const _NOEXCEPT {return base::end();}
+
+    _LIBCPP_INLINE_VISIBILITY
+          reverse_iterator rbegin() _NOEXCEPT
+            {return       reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rbegin()  const _NOEXCEPT
+        {return const_reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+          reverse_iterator rend() _NOEXCEPT
+            {return       reverse_iterator(begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rend()    const _NOEXCEPT
+        {return const_reverse_iterator(begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crbegin() const _NOEXCEPT
+        {return const_reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crend()   const _NOEXCEPT
+        {return const_reverse_iterator(begin());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference front()
+    {
+        _LIBCPP_ASSERT(!empty(), "list::front called on empty list");
+        return base::__end_.__next_->__as_node()->__value_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference front() const
+    {
+        _LIBCPP_ASSERT(!empty(), "list::front called on empty list");
+        return base::__end_.__next_->__as_node()->__value_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    reference back()
+    {
+        _LIBCPP_ASSERT(!empty(), "list::back called on empty list");
+        return base::__end_.__prev_->__as_node()->__value_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference back() const
+    {
+        _LIBCPP_ASSERT(!empty(), "list::back called on empty list");
+        return base::__end_.__prev_->__as_node()->__value_;
+    }
+
+#ifndef _LIBCPP_CXX03_LANG
+    void push_front(value_type&& __x);
+    void push_back(value_type&& __x);
+
+    template <class... _Args>
+#if _LIBCPP_STD_VER > 14
+       reference emplace_front(_Args&&... __args);
+#else
+       void      emplace_front(_Args&&... __args);
+#endif
+    template <class... _Args>
+#if _LIBCPP_STD_VER > 14
+        reference emplace_back(_Args&&... __args);
+#else
+       void       emplace_back(_Args&&... __args);
+#endif
+    template <class... _Args>
+        iterator emplace(const_iterator __p, _Args&&... __args);
+
+    iterator insert(const_iterator __p, value_type&& __x);
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, initializer_list<value_type> __il)
+        {return insert(__p, __il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+
+    void push_front(const value_type& __x);
+    void push_back(const value_type& __x);
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _Arg>
+    _LIBCPP_INLINE_VISIBILITY
+    void __emplace_back(_Arg&& __arg) { emplace_back(_VSTD::forward<_Arg>(__arg)); }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    void __emplace_back(value_type const& __arg) { push_back(__arg); }
+#endif
+
+    iterator insert(const_iterator __p, const value_type& __x);
+    iterator insert(const_iterator __p, size_type __n, const value_type& __x);
+    template <class _InpIter>
+        iterator insert(const_iterator __p, _InpIter __f, _InpIter __l,
+             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type* = 0);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(list& __c)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT
+#else
+        _NOEXCEPT_(!__node_alloc_traits::propagate_on_container_swap::value ||
+                   __is_nothrow_swappable<__node_allocator>::value)
+#endif
+        {base::swap(__c);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT {base::clear();}
+
+    void pop_front();
+    void pop_back();
+
+    iterator erase(const_iterator __p);
+    iterator erase(const_iterator __f, const_iterator __l);
+
+    void resize(size_type __n);
+    void resize(size_type __n, const value_type& __x);
+
+    void splice(const_iterator __p, list& __c);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void splice(const_iterator __p, list&& __c) {splice(__p, __c);}
+    _LIBCPP_INLINE_VISIBILITY
+    void splice(const_iterator __p, list&& __c, const_iterator __i)
+        {splice(__p, __c, __i);}
+    _LIBCPP_INLINE_VISIBILITY
+    void splice(const_iterator __p, list&& __c, const_iterator __f, const_iterator __l)
+        {splice(__p, __c, __f, __l);}
+#endif
+    void splice(const_iterator __p, list& __c, const_iterator __i);
+    void splice(const_iterator __p, list& __c, const_iterator __f, const_iterator __l);
+
+    __remove_return_type remove(const value_type& __x);
+    template <class _Pred> __remove_return_type remove_if(_Pred __pred);
+    _LIBCPP_INLINE_VISIBILITY
+    __remove_return_type unique() { return unique(__equal_to<value_type>()); }
+    template <class _BinaryPred>
+        __remove_return_type unique(_BinaryPred __binary_pred);
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(list& __c);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(list&& __c) {merge(__c);}
+
+    template <class _Comp>
+    _LIBCPP_INLINE_VISIBILITY
+        void merge(list&& __c, _Comp __comp) {merge(__c, __comp);}
+#endif
+    template <class _Comp>
+        void merge(list& __c, _Comp __comp);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void sort();
+    template <class _Comp>
+        _LIBCPP_INLINE_VISIBILITY
+        void sort(_Comp __comp);
+
+    void reverse() _NOEXCEPT;
+
+    bool __invariants() const;
+
+    typedef __allocator_destructor<__node_allocator> __node_destructor;
+    typedef unique_ptr<__node, __node_destructor> __hold_pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hold_pointer __allocate_node(__node_allocator& __na) {
+      __node_pointer __p = __node_alloc_traits::allocate(__na, 1);
+      __p->__prev_ = nullptr;
+      return __hold_pointer(__p, __node_destructor(__na, 1));
+    }
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+    bool __dereferenceable(const const_iterator* __i) const;
+    bool __decrementable(const const_iterator* __i) const;
+    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
+    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    static void __link_nodes  (__link_pointer __p, __link_pointer __f, __link_pointer __l);
+    _LIBCPP_INLINE_VISIBILITY
+    void __link_nodes_at_front(__link_pointer __f, __link_pointer __l);
+    _LIBCPP_INLINE_VISIBILITY
+    void __link_nodes_at_back (__link_pointer __f, __link_pointer __l);
+    iterator __iterator(size_type __n);
+    template <class _Comp>
+        static iterator __sort(iterator __f1, iterator __e2, size_type __n, _Comp& __comp);
+
+    void __move_assign(list& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value);
+    void __move_assign(list& __c, false_type);
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator,
+         class _Alloc = allocator<__iter_value_type<_InputIterator>>,
+         class = enable_if_t<__is_allocator<_Alloc>::value>
+         >
+list(_InputIterator, _InputIterator)
+  -> list<__iter_value_type<_InputIterator>, _Alloc>;
+
+template<class _InputIterator,
+         class _Alloc,
+         class = enable_if_t<__is_allocator<_Alloc>::value>
+         >
+list(_InputIterator, _InputIterator, _Alloc)
+  -> list<__iter_value_type<_InputIterator>, _Alloc>;
+#endif
+
+// Link in nodes [__f, __l] just prior to __p
+template <class _Tp, class _Alloc>
+inline
+void
+list<_Tp, _Alloc>::__link_nodes(__link_pointer __p, __link_pointer __f, __link_pointer __l)
+{
+    __p->__prev_->__next_ = __f;
+    __f->__prev_ = __p->__prev_;
+    __p->__prev_ = __l;
+    __l->__next_ = __p;
+}
+
+// Link in nodes [__f, __l] at the front of the list
+template <class _Tp, class _Alloc>
+inline
+void
+list<_Tp, _Alloc>::__link_nodes_at_front(__link_pointer __f, __link_pointer __l)
+{
+    __f->__prev_ = base::__end_as_link();
+    __l->__next_ = base::__end_.__next_;
+    __l->__next_->__prev_ = __l;
+    base::__end_.__next_ = __f;
+}
+
+// Link in nodes [__f, __l] at the back of the list
+template <class _Tp, class _Alloc>
+inline
+void
+list<_Tp, _Alloc>::__link_nodes_at_back(__link_pointer __f, __link_pointer __l)
+{
+    __l->__next_ = base::__end_as_link();
+    __f->__prev_ = base::__end_.__prev_;
+    __f->__prev_->__next_ = __f;
+    base::__end_.__prev_ = __l;
+}
+
+
+template <class _Tp, class _Alloc>
+inline
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::__iterator(size_type __n)
+{
+    return __n <= base::__sz() / 2 ? _VSTD::next(begin(), __n)
+                                   : _VSTD::prev(end(), base::__sz() - __n);
+}
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(size_type __n)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __n > 0; --__n)
+#ifndef _LIBCPP_CXX03_LANG
+        emplace_back();
+#else
+        push_back(value_type());
+#endif
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(size_type __n, const allocator_type& __a) : base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __n > 0; --__n)
+        emplace_back();
+}
+#endif
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(size_type __n, const value_type& __x)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __n > 0; --__n)
+        push_back(__x);
+}
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(size_type __n, const value_type& __x, const allocator_type& __a)
+    : base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __n > 0; --__n)
+        push_back(__x);
+}
+
+template <class _Tp, class _Alloc>
+template <class _InpIter>
+list<_Tp, _Alloc>::list(_InpIter __f, _InpIter __l,
+                        typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type*)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __f != __l; ++__f)
+        __emplace_back(*__f);
+}
+
+template <class _Tp, class _Alloc>
+template <class _InpIter>
+list<_Tp, _Alloc>::list(_InpIter __f, _InpIter __l, const allocator_type& __a,
+                        typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type*)
+    : base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __f != __l; ++__f)
+        __emplace_back(*__f);
+}
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(const list& __c)
+    : base(__node_alloc_traits::select_on_container_copy_construction(
+          __c.__node_alloc())) {
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (const_iterator __i = __c.begin(), __e = __c.end(); __i != __e; ++__i)
+        push_back(*__i);
+}
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(const list& __c, const __identity_t<allocator_type>& __a)
+    : base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (const_iterator __i = __c.begin(), __e = __c.end(); __i != __e; ++__i)
+        push_back(*__i);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(initializer_list<value_type> __il, const allocator_type& __a)
+    : base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (typename initializer_list<value_type>::const_iterator __i = __il.begin(),
+            __e = __il.end(); __i != __e; ++__i)
+        push_back(*__i);
+}
+
+template <class _Tp, class _Alloc>
+list<_Tp, _Alloc>::list(initializer_list<value_type> __il)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (typename initializer_list<value_type>::const_iterator __i = __il.begin(),
+            __e = __il.end(); __i != __e; ++__i)
+        push_back(*__i);
+}
+
+template <class _Tp, class _Alloc>
+inline list<_Tp, _Alloc>::list(list&& __c)
+    _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value)
+    : base(_VSTD::move(__c.__node_alloc())) {
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    splice(end(), __c);
+}
+
+template <class _Tp, class _Alloc>
+inline
+list<_Tp, _Alloc>::list(list&& __c, const __identity_t<allocator_type>& __a)
+    : base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    if (__a == __c.get_allocator())
+        splice(end(), __c);
+    else
+    {
+        typedef move_iterator<iterator> _Ip;
+        assign(_Ip(__c.begin()), _Ip(__c.end()));
+    }
+}
+
+template <class _Tp, class _Alloc>
+inline
+list<_Tp, _Alloc>&
+list<_Tp, _Alloc>::operator=(list&& __c)
+        _NOEXCEPT_(
+            __node_alloc_traits::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<__node_allocator>::value)
+{
+    __move_assign(__c, integral_constant<bool,
+          __node_alloc_traits::propagate_on_container_move_assignment::value>());
+    return *this;
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::__move_assign(list& __c, false_type)
+{
+    if (base::__node_alloc() != __c.__node_alloc())
+    {
+        typedef move_iterator<iterator> _Ip;
+        assign(_Ip(__c.begin()), _Ip(__c.end()));
+    }
+    else
+        __move_assign(__c, true_type());
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::__move_assign(list& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value)
+{
+    clear();
+    base::__move_assign_alloc(__c);
+    splice(end(), __c);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+inline
+list<_Tp, _Alloc>&
+list<_Tp, _Alloc>::operator=(const list& __c)
+{
+    if (this != _VSTD::addressof(__c))
+    {
+        base::__copy_assign_alloc(__c);
+        assign(__c.begin(), __c.end());
+    }
+    return *this;
+}
+
+template <class _Tp, class _Alloc>
+template <class _InpIter>
+void
+list<_Tp, _Alloc>::assign(_InpIter __f, _InpIter __l,
+                          typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type*)
+{
+    iterator __i = begin();
+    iterator __e = end();
+    for (; __f != __l && __i != __e; ++__f, (void) ++__i)
+        *__i = *__f;
+    if (__i == __e)
+        insert(__e, __f, __l);
+    else
+        erase(__i, __e);
+#if _LIBCPP_DEBUG_LEVEL == 2
+      __get_db()->__invalidate_all(this);
+#endif
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::assign(size_type __n, const value_type& __x)
+{
+    iterator __i = begin();
+    iterator __e = end();
+    for (; __n > 0 && __i != __e; --__n, (void) ++__i)
+        *__i = __x;
+    if (__i == __e)
+        insert(__e, __n, __x);
+    else
+        erase(__i, __e);
+#if _LIBCPP_DEBUG_LEVEL == 2
+      __get_db()->__invalidate_all(this);
+#endif
+}
+
+template <class _Tp, class _Alloc>
+inline
+_Alloc
+list<_Tp, _Alloc>::get_allocator() const _NOEXCEPT
+{
+    return allocator_type(base::__node_alloc());
+}
+
+template <class _Tp, class _Alloc>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::insert(const_iterator __p, const value_type& __x)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::insert(iterator, x) called with an iterator not"
+        " referring to this list");
+#endif
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+    __link_nodes(__p.__ptr_, __hold->__as_link(), __hold->__as_link());
+    ++base::__sz();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(__hold.release()->__as_link(), this);
+#else
+    return iterator(__hold.release()->__as_link());
+#endif
+}
+
+template <class _Tp, class _Alloc>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::insert(const_iterator __p, size_type __n, const value_type& __x)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::insert(iterator, n, x) called with an iterator not"
+        " referring to this list");
+    iterator __r(__p.__ptr_, this);
+#else
+    iterator __r(__p.__ptr_);
+#endif
+    if (__n > 0)
+    {
+        size_type __ds = 0;
+        __node_allocator& __na = base::__node_alloc();
+        __hold_pointer __hold = __allocate_node(__na);
+        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+        ++__ds;
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __r = iterator(__hold->__as_link(), this);
+#else
+        __r = iterator(__hold->__as_link());
+#endif
+        __hold.release();
+        iterator __e = __r;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (--__n; __n != 0; --__n, (void) ++__e, ++__ds)
+            {
+                __hold.reset(__node_alloc_traits::allocate(__na, 1));
+                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+                __e.__ptr_->__next_ = __hold->__as_link();
+                __hold->__prev_ = __e.__ptr_;
+                __hold.release();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            while (true)
+            {
+                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
+                __link_pointer __prev = __e.__ptr_->__prev_;
+                __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 1);
+                if (__prev == 0)
+                    break;
+#if _LIBCPP_DEBUG_LEVEL == 2
+                __e = iterator(__prev, this);
+#else
+                __e = iterator(__prev);
+#endif
+            }
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __link_nodes(__p.__ptr_, __r.__ptr_, __e.__ptr_);
+        base::__sz() += __ds;
+    }
+    return __r;
+}
+
+template <class _Tp, class _Alloc>
+template <class _InpIter>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::insert(const_iterator __p, _InpIter __f, _InpIter __l,
+             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type*)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
+        "list::insert(iterator, range) called with an iterator not"
+        " referring to this list");
+    iterator __r(__p.__ptr_, this);
+#else
+    iterator __r(__p.__ptr_);
+#endif
+    if (__f != __l)
+    {
+        size_type __ds = 0;
+        __node_allocator& __na = base::__node_alloc();
+        __hold_pointer __hold = __allocate_node(__na);
+        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), *__f);
+        ++__ds;
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __r = iterator(__hold.get()->__as_link(), this);
+#else
+        __r = iterator(__hold.get()->__as_link());
+#endif
+        __hold.release();
+        iterator __e = __r;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (++__f; __f != __l; ++__f, (void) ++__e, ++__ds)
+            {
+                __hold.reset(__node_alloc_traits::allocate(__na, 1));
+                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), *__f);
+                __e.__ptr_->__next_ = __hold.get()->__as_link();
+                __hold->__prev_ = __e.__ptr_;
+                __hold.release();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            while (true)
+            {
+                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
+                __link_pointer __prev = __e.__ptr_->__prev_;
+                __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 1);
+                if (__prev == 0)
+                    break;
+#if _LIBCPP_DEBUG_LEVEL == 2
+                __e = iterator(__prev, this);
+#else
+                __e = iterator(__prev);
+#endif
+            }
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __link_nodes(__p.__ptr_, __r.__ptr_, __e.__ptr_);
+        base::__sz() += __ds;
+    }
+    return __r;
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::push_front(const value_type& __x)
+{
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+    __link_pointer __nl = __hold->__as_link();
+    __link_nodes_at_front(__nl, __nl);
+    ++base::__sz();
+    __hold.release();
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::push_back(const value_type& __x)
+{
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+    __link_nodes_at_back(__hold.get()->__as_link(), __hold.get()->__as_link());
+    ++base::__sz();
+    __hold.release();
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::push_front(value_type&& __x)
+{
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::move(__x));
+    __link_nodes_at_front(__hold.get()->__as_link(), __hold.get()->__as_link());
+    ++base::__sz();
+    __hold.release();
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::push_back(value_type&& __x)
+{
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::move(__x));
+    __link_nodes_at_back(__hold.get()->__as_link(), __hold.get()->__as_link());
+    ++base::__sz();
+    __hold.release();
+}
+
+template <class _Tp, class _Alloc>
+template <class... _Args>
+#if _LIBCPP_STD_VER > 14
+typename list<_Tp, _Alloc>::reference
+#else
+void
+#endif
+list<_Tp, _Alloc>::emplace_front(_Args&&... __args)
+{
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::forward<_Args>(__args)...);
+    __link_nodes_at_front(__hold.get()->__as_link(), __hold.get()->__as_link());
+    ++base::__sz();
+#if _LIBCPP_STD_VER > 14
+    return __hold.release()->__value_;
+#else
+    __hold.release();
+#endif
+}
+
+template <class _Tp, class _Alloc>
+template <class... _Args>
+#if _LIBCPP_STD_VER > 14
+typename list<_Tp, _Alloc>::reference
+#else
+void
+#endif
+list<_Tp, _Alloc>::emplace_back(_Args&&... __args)
+{
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::forward<_Args>(__args)...);
+    __link_pointer __nl = __hold->__as_link();
+    __link_nodes_at_back(__nl, __nl);
+    ++base::__sz();
+#if _LIBCPP_STD_VER > 14
+    return __hold.release()->__value_;
+#else
+    __hold.release();
+#endif
+}
+
+template <class _Tp, class _Alloc>
+template <class... _Args>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::emplace(const_iterator __p, _Args&&... __args)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::emplace(iterator, args...) called with an iterator not"
+        " referring to this list");
+#endif
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::forward<_Args>(__args)...);
+    __link_pointer __nl = __hold.get()->__as_link();
+    __link_nodes(__p.__ptr_, __nl, __nl);
+    ++base::__sz();
+    __hold.release();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(__nl, this);
+#else
+    return iterator(__nl);
+#endif
+}
+
+template <class _Tp, class _Alloc>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::insert(const_iterator __p, value_type&& __x)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::insert(iterator, x) called with an iterator not"
+        " referring to this list");
+#endif
+    __node_allocator& __na = base::__node_alloc();
+    __hold_pointer __hold = __allocate_node(__na);
+    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::move(__x));
+    __link_pointer __nl = __hold->__as_link();
+    __link_nodes(__p.__ptr_, __nl, __nl);
+    ++base::__sz();
+    __hold.release();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(__nl, this);
+#else
+    return iterator(__nl);
+#endif
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::pop_front()
+{
+    _LIBCPP_ASSERT(!empty(), "list::pop_front() called with empty list");
+    __node_allocator& __na = base::__node_alloc();
+    __link_pointer __n = base::__end_.__next_;
+    base::__unlink_nodes(__n, __n);
+    --base::__sz();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __c_node* __c = __get_db()->__find_c_and_lock(this);
+    for (__i_node** __p = __c->end_; __p != __c->beg_; )
+    {
+        --__p;
+        iterator* __i = static_cast<iterator*>((*__p)->__i_);
+        if (__i->__ptr_ == __n)
+        {
+            (*__p)->__c_ = nullptr;
+            if (--__c->end_ != __p)
+                _VSTD::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
+        }
+    }
+    __get_db()->unlock();
+#endif
+    __node_pointer __np = __n->__as_node();
+    __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
+    __node_alloc_traits::deallocate(__na, __np, 1);
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::pop_back()
+{
+    _LIBCPP_ASSERT(!empty(), "list::pop_back() called on an empty list");
+    __node_allocator& __na = base::__node_alloc();
+    __link_pointer __n = base::__end_.__prev_;
+    base::__unlink_nodes(__n, __n);
+    --base::__sz();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __c_node* __c = __get_db()->__find_c_and_lock(this);
+    for (__i_node** __p = __c->end_; __p != __c->beg_; )
+    {
+        --__p;
+        iterator* __i = static_cast<iterator*>((*__p)->__i_);
+        if (__i->__ptr_ == __n)
+        {
+            (*__p)->__c_ = nullptr;
+            if (--__c->end_ != __p)
+                _VSTD::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
+        }
+    }
+    __get_db()->unlock();
+#endif
+    __node_pointer __np = __n->__as_node();
+    __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
+    __node_alloc_traits::deallocate(__na, __np, 1);
+}
+
+template <class _Tp, class _Alloc>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::erase(const_iterator __p)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::erase(iterator) called with an iterator not"
+        " referring to this list");
+#endif
+    _LIBCPP_ASSERT(__p != end(),
+        "list::erase(iterator) called with a non-dereferenceable iterator");
+    __node_allocator& __na = base::__node_alloc();
+    __link_pointer __n = __p.__ptr_;
+    __link_pointer __r = __n->__next_;
+    base::__unlink_nodes(__n, __n);
+    --base::__sz();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __c_node* __c = __get_db()->__find_c_and_lock(this);
+    for (__i_node** __ip = __c->end_; __ip != __c->beg_; )
+    {
+        --__ip;
+        iterator* __i = static_cast<iterator*>((*__ip)->__i_);
+        if (__i->__ptr_ == __n)
+        {
+            (*__ip)->__c_ = nullptr;
+            if (--__c->end_ != __ip)
+                _VSTD::memmove(__ip, __ip+1, (__c->end_ - __ip)*sizeof(__i_node*));
+        }
+    }
+    __get_db()->unlock();
+#endif
+    __node_pointer __np = __n->__as_node();
+    __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
+    __node_alloc_traits::deallocate(__na, __np, 1);
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(__r, this);
+#else
+    return iterator(__r);
+#endif
+}
+
+template <class _Tp, class _Alloc>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::erase(const_iterator __f, const_iterator __l)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__f)) == this,
+        "list::erase(iterator, iterator) called with an iterator not"
+        " referring to this list");
+   _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__l)) == this,
+        "list::erase(iterator, iterator) called with an iterator not"
+        " referring to this list");
+#endif
+    if (__f != __l)
+    {
+        __node_allocator& __na = base::__node_alloc();
+        base::__unlink_nodes(__f.__ptr_, __l.__ptr_->__prev_);
+        while (__f != __l)
+        {
+            __link_pointer __n = __f.__ptr_;
+            ++__f;
+            --base::__sz();
+#if _LIBCPP_DEBUG_LEVEL == 2
+            __c_node* __c = __get_db()->__find_c_and_lock(this);
+            for (__i_node** __p = __c->end_; __p != __c->beg_; )
+            {
+                --__p;
+                iterator* __i = static_cast<iterator*>((*__p)->__i_);
+                if (__i->__ptr_ == __n)
+                {
+                    (*__p)->__c_ = nullptr;
+                    if (--__c->end_ != __p)
+                        _VSTD::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
+                }
+            }
+            __get_db()->unlock();
+#endif
+            __node_pointer __np = __n->__as_node();
+            __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
+            __node_alloc_traits::deallocate(__na, __np, 1);
+        }
+    }
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(__l.__ptr_, this);
+#else
+    return iterator(__l.__ptr_);
+#endif
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::resize(size_type __n)
+{
+    if (__n < base::__sz())
+        erase(__iterator(__n), end());
+    else if (__n > base::__sz())
+    {
+        __n -= base::__sz();
+        size_type __ds = 0;
+        __node_allocator& __na = base::__node_alloc();
+        __hold_pointer __hold = __allocate_node(__na);
+        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_));
+        ++__ds;
+#if _LIBCPP_DEBUG_LEVEL == 2
+        iterator __r = iterator(__hold.release()->__as_link(), this);
+#else
+        iterator __r = iterator(__hold.release()->__as_link());
+#endif
+        iterator __e = __r;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (--__n; __n != 0; --__n, (void) ++__e, ++__ds)
+            {
+                __hold.reset(__node_alloc_traits::allocate(__na, 1));
+                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_));
+                __e.__ptr_->__next_ = __hold.get()->__as_link();
+                __hold->__prev_ = __e.__ptr_;
+                __hold.release();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            while (true)
+            {
+                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
+                __link_pointer __prev = __e.__ptr_->__prev_;
+                __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 1);
+                if (__prev == 0)
+                    break;
+#if _LIBCPP_DEBUG_LEVEL == 2
+                __e = iterator(__prev, this);
+#else
+                __e = iterator(__prev);
+#endif
+            }
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __link_nodes_at_back(__r.__ptr_, __e.__ptr_);
+        base::__sz() += __ds;
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::resize(size_type __n, const value_type& __x)
+{
+    if (__n < base::__sz())
+        erase(__iterator(__n), end());
+    else if (__n > base::__sz())
+    {
+        __n -= base::__sz();
+        size_type __ds = 0;
+        __node_allocator& __na = base::__node_alloc();
+        __hold_pointer __hold = __allocate_node(__na);
+        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+        ++__ds;
+        __link_pointer __nl = __hold.release()->__as_link();
+#if _LIBCPP_DEBUG_LEVEL == 2
+        iterator __r = iterator(__nl, this);
+#else
+        iterator __r = iterator(__nl);
+#endif
+        iterator __e = __r;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (--__n; __n != 0; --__n, (void) ++__e, ++__ds)
+            {
+                __hold.reset(__node_alloc_traits::allocate(__na, 1));
+                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
+                __e.__ptr_->__next_ = __hold.get()->__as_link();
+                __hold->__prev_ = __e.__ptr_;
+                __hold.release();
+            }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            while (true)
+            {
+                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
+                __link_pointer __prev = __e.__ptr_->__prev_;
+                __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 1);
+                if (__prev == 0)
+                    break;
+#if _LIBCPP_DEBUG_LEVEL == 2
+                __e = iterator(__prev, this);
+#else
+                __e = iterator(__prev);
+#endif
+            }
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __link_nodes(base::__end_as_link(), __r.__ptr_, __e.__ptr_);
+        base::__sz() += __ds;
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::splice(const_iterator __p, list& __c)
+{
+    _LIBCPP_ASSERT(this != &__c,
+                   "list::splice(iterator, list) called with this == &list");
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::splice(iterator, list) called with an iterator not"
+        " referring to this list");
+#endif
+    if (!__c.empty())
+    {
+        __link_pointer __f = __c.__end_.__next_;
+        __link_pointer __l = __c.__end_.__prev_;
+        base::__unlink_nodes(__f, __l);
+        __link_nodes(__p.__ptr_, __f, __l);
+        base::__sz() += __c.__sz();
+        __c.__sz() = 0;
+#if _LIBCPP_DEBUG_LEVEL == 2
+        if (&__c != this) {
+            __libcpp_db* __db = __get_db();
+            __c_node* __cn1 = __db->__find_c_and_lock(this);
+            __c_node* __cn2 = __db->__find_c(&__c);
+            for (__i_node** __ip = __cn2->end_; __ip != __cn2->beg_;)
+            {
+                --__ip;
+                iterator* __i = static_cast<iterator*>((*__ip)->__i_);
+                if (__i->__ptr_ != __c.__end_as_link())
+                {
+                    __cn1->__add(*__ip);
+                    (*__ip)->__c_ = __cn1;
+                    if (--__cn2->end_ != __ip)
+                        memmove(__ip, __ip+1, (__cn2->end_ - __ip)*sizeof(__i_node*));
+                }
+            }
+            __db->unlock();
+        }
+#endif
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __i)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::splice(iterator, list, iterator) called with the first iterator"
+        " not referring to this list");
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__i) == &__c,
+        "list::splice(iterator, list, iterator) called with the second iterator"
+        " not referring to the list argument");
+    _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(&__i),
+        "list::splice(iterator, list, iterator) called with the second iterator"
+        " not dereferenceable");
+#endif
+    if (__p.__ptr_ != __i.__ptr_ && __p.__ptr_ != __i.__ptr_->__next_)
+    {
+        __link_pointer __f = __i.__ptr_;
+        base::__unlink_nodes(__f, __f);
+        __link_nodes(__p.__ptr_, __f, __f);
+        --__c.__sz();
+        ++base::__sz();
+#if _LIBCPP_DEBUG_LEVEL == 2
+        if (&__c != this) {
+            __libcpp_db* __db = __get_db();
+            __c_node* __cn1 = __db->__find_c_and_lock(this);
+            __c_node* __cn2 = __db->__find_c(&__c);
+            for (__i_node** __ip = __cn2->end_; __ip != __cn2->beg_;)
+            {
+                --__ip;
+                iterator* __j = static_cast<iterator*>((*__ip)->__i_);
+                if (__j->__ptr_ == __f)
+                {
+                    __cn1->__add(*__ip);
+                    (*__ip)->__c_ = __cn1;
+                    if (--__cn2->end_ != __ip)
+                        _VSTD::memmove(__ip, __ip+1, (__cn2->end_ - __ip)*sizeof(__i_node*));
+                }
+            }
+            __db->unlock();
+        }
+#endif
+    }
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __f, const_iterator __l)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+        "list::splice(iterator, list, iterator, iterator) called with first iterator not"
+        " referring to this list");
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__f) == &__c,
+        "list::splice(iterator, list, iterator, iterator) called with second iterator not"
+        " referring to the list argument");
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__l) == &__c,
+        "list::splice(iterator, list, iterator, iterator) called with third iterator not"
+        " referring to the list argument");
+    if (this == &__c)
+    {
+        for (const_iterator __i = __f; __i != __l; ++__i)
+            _LIBCPP_ASSERT(__i != __p,
+                           "list::splice(iterator, list, iterator, iterator)"
+                           " called with the first iterator within the range"
+                           " of the second and third iterators");
+    }
+#endif
+    if (__f != __l)
+    {
+        __link_pointer __first = __f.__ptr_;
+        --__l;
+        __link_pointer __last = __l.__ptr_;
+        if (this != &__c)
+        {
+            size_type __s = _VSTD::distance(__f, __l) + 1;
+            __c.__sz() -= __s;
+            base::__sz() += __s;
+        }
+        base::__unlink_nodes(__first, __last);
+        __link_nodes(__p.__ptr_, __first, __last);
+#if _LIBCPP_DEBUG_LEVEL == 2
+        if (&__c != this) {
+            __libcpp_db* __db = __get_db();
+            __c_node* __cn1 = __db->__find_c_and_lock(this);
+            __c_node* __cn2 = __db->__find_c(&__c);
+            for (__i_node** __ip = __cn2->end_; __ip != __cn2->beg_;)
+            {
+                --__ip;
+                iterator* __j = static_cast<iterator*>((*__ip)->__i_);
+                for (__link_pointer __k = __f.__ptr_;
+                                              __k != __l.__ptr_; __k = __k->__next_)
+                {
+                    if (__j->__ptr_ == __k)
+                    {
+                        __cn1->__add(*__ip);
+                        (*__ip)->__c_ = __cn1;
+                        if (--__cn2->end_ != __ip)
+                            _VSTD::memmove(__ip, __ip+1, (__cn2->end_ - __ip)*sizeof(__i_node*));
+                    }
+                }
+            }
+            __db->unlock();
+        }
+#endif
+    }
+}
+
+template <class _Tp, class _Alloc>
+typename list<_Tp, _Alloc>::__remove_return_type
+list<_Tp, _Alloc>::remove(const value_type& __x)
+{
+    list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
+    for (const_iterator __i = begin(), __e = end(); __i != __e;)
+    {
+        if (*__i == __x)
+        {
+            const_iterator __j = _VSTD::next(__i);
+            for (; __j != __e && *__j == __x; ++__j)
+                ;
+            __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
+            __i = __j;
+            if (__i != __e)
+                ++__i;
+        }
+        else
+            ++__i;
+    }
+
+    return (__remove_return_type) __deleted_nodes.size();
+}
+
+template <class _Tp, class _Alloc>
+template <class _Pred>
+typename list<_Tp, _Alloc>::__remove_return_type
+list<_Tp, _Alloc>::remove_if(_Pred __pred)
+{
+    list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
+    for (iterator __i = begin(), __e = end(); __i != __e;)
+    {
+        if (__pred(*__i))
+        {
+            iterator __j = _VSTD::next(__i);
+            for (; __j != __e && __pred(*__j); ++__j)
+                ;
+            __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
+            __i = __j;
+            if (__i != __e)
+                ++__i;
+        }
+        else
+            ++__i;
+    }
+
+    return (__remove_return_type) __deleted_nodes.size();
+}
+
+template <class _Tp, class _Alloc>
+template <class _BinaryPred>
+typename list<_Tp, _Alloc>::__remove_return_type
+list<_Tp, _Alloc>::unique(_BinaryPred __binary_pred)
+{
+    list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
+    for (iterator __i = begin(), __e = end(); __i != __e;)
+    {
+        iterator __j = _VSTD::next(__i);
+        for (; __j != __e && __binary_pred(*__i, *__j); ++__j)
+            ;
+        if (++__i != __j) {
+            __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
+            __i = __j;
+            }
+    }
+
+    return (__remove_return_type) __deleted_nodes.size();
+}
+
+template <class _Tp, class _Alloc>
+inline
+void
+list<_Tp, _Alloc>::merge(list& __c)
+{
+    merge(__c, __less<value_type>());
+}
+
+template <class _Tp, class _Alloc>
+template <class _Comp>
+void
+list<_Tp, _Alloc>::merge(list& __c, _Comp __comp)
+{
+    if (this != _VSTD::addressof(__c))
+    {
+        iterator __f1 = begin();
+        iterator __e1 = end();
+        iterator __f2 = __c.begin();
+        iterator __e2 = __c.end();
+        while (__f1 != __e1 && __f2 != __e2)
+        {
+            if (__comp(*__f2, *__f1))
+            {
+                size_type __ds = 1;
+                iterator __m2 = _VSTD::next(__f2);
+                for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2, (void) ++__ds)
+                    ;
+                base::__sz() += __ds;
+                __c.__sz() -= __ds;
+                __link_pointer __f = __f2.__ptr_;
+                __link_pointer __l = __m2.__ptr_->__prev_;
+                __f2 = __m2;
+                base::__unlink_nodes(__f, __l);
+                __m2 = _VSTD::next(__f1);
+                __link_nodes(__f1.__ptr_, __f, __l);
+                __f1 = __m2;
+            }
+            else
+                ++__f1;
+        }
+        splice(__e1, __c);
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __libcpp_db* __db = __get_db();
+        __c_node* __cn1 = __db->__find_c_and_lock(this);
+        __c_node* __cn2 = __db->__find_c(&__c);
+        for (__i_node** __p = __cn2->end_; __p != __cn2->beg_;)
+        {
+            --__p;
+            iterator* __i = static_cast<iterator*>((*__p)->__i_);
+            if (__i->__ptr_ != __c.__end_as_link())
+            {
+                __cn1->__add(*__p);
+                (*__p)->__c_ = __cn1;
+                if (--__cn2->end_ != __p)
+                    _VSTD::memmove(__p, __p+1, (__cn2->end_ - __p)*sizeof(__i_node*));
+            }
+        }
+        __db->unlock();
+#endif
+    }
+}
+
+template <class _Tp, class _Alloc>
+inline
+void
+list<_Tp, _Alloc>::sort()
+{
+    sort(__less<value_type>());
+}
+
+template <class _Tp, class _Alloc>
+template <class _Comp>
+inline
+void
+list<_Tp, _Alloc>::sort(_Comp __comp)
+{
+    __sort(begin(), end(), base::__sz(), __comp);
+}
+
+template <class _Tp, class _Alloc>
+template <class _Comp>
+typename list<_Tp, _Alloc>::iterator
+list<_Tp, _Alloc>::__sort(iterator __f1, iterator __e2, size_type __n, _Comp& __comp)
+{
+    switch (__n)
+    {
+    case 0:
+    case 1:
+        return __f1;
+    case 2:
+        if (__comp(*--__e2, *__f1))
+        {
+            __link_pointer __f = __e2.__ptr_;
+            base::__unlink_nodes(__f, __f);
+            __link_nodes(__f1.__ptr_, __f, __f);
+            return __e2;
+        }
+        return __f1;
+    }
+    size_type __n2 = __n / 2;
+    iterator __e1 = _VSTD::next(__f1, __n2);
+    iterator  __r = __f1 = __sort(__f1, __e1, __n2, __comp);
+    iterator __f2 = __e1 = __sort(__e1, __e2, __n - __n2, __comp);
+    if (__comp(*__f2, *__f1))
+    {
+        iterator __m2 = _VSTD::next(__f2);
+        for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2)
+            ;
+        __link_pointer __f = __f2.__ptr_;
+        __link_pointer __l = __m2.__ptr_->__prev_;
+        __r = __f2;
+        __e1 = __f2 = __m2;
+        base::__unlink_nodes(__f, __l);
+        __m2 = _VSTD::next(__f1);
+        __link_nodes(__f1.__ptr_, __f, __l);
+        __f1 = __m2;
+    }
+    else
+        ++__f1;
+    while (__f1 != __e1 && __f2 != __e2)
+    {
+        if (__comp(*__f2, *__f1))
+        {
+            iterator __m2 = _VSTD::next(__f2);
+            for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2)
+                ;
+            __link_pointer __f = __f2.__ptr_;
+            __link_pointer __l = __m2.__ptr_->__prev_;
+            if (__e1 == __f2)
+                __e1 = __m2;
+            __f2 = __m2;
+            base::__unlink_nodes(__f, __l);
+            __m2 = _VSTD::next(__f1);
+            __link_nodes(__f1.__ptr_, __f, __l);
+            __f1 = __m2;
+        }
+        else
+            ++__f1;
+    }
+    return __r;
+}
+
+template <class _Tp, class _Alloc>
+void
+list<_Tp, _Alloc>::reverse() _NOEXCEPT
+{
+    if (base::__sz() > 1)
+    {
+        iterator __e = end();
+        for (iterator __i = begin(); __i.__ptr_ != __e.__ptr_;)
+        {
+            _VSTD::swap(__i.__ptr_->__prev_, __i.__ptr_->__next_);
+            __i.__ptr_ = __i.__ptr_->__prev_;
+        }
+        _VSTD::swap(__e.__ptr_->__prev_, __e.__ptr_->__next_);
+    }
+}
+
+template <class _Tp, class _Alloc>
+bool
+list<_Tp, _Alloc>::__invariants() const
+{
+    return size() == _VSTD::distance(begin(), end());
+}
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+template <class _Tp, class _Alloc>
+bool
+list<_Tp, _Alloc>::__dereferenceable(const const_iterator* __i) const
+{
+    return __i->__ptr_ != this->__end_as_link();
+}
+
+template <class _Tp, class _Alloc>
+bool
+list<_Tp, _Alloc>::__decrementable(const const_iterator* __i) const
+{
+    return !empty() &&  __i->__ptr_ != base::__end_.__next_;
+}
+
+template <class _Tp, class _Alloc>
+bool
+list<_Tp, _Alloc>::__addable(const const_iterator*, ptrdiff_t) const
+{
+    return false;
+}
+
+template <class _Tp, class _Alloc>
+bool
+list<_Tp, _Alloc>::__subscriptable(const const_iterator*, ptrdiff_t) const
+{
+    return false;
+}
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+{
+    return __x.size() == __y.size() && _VSTD::equal(__x.begin(), __x.end(), __y.begin());
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+{
+    return _VSTD::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+{
+    return __y < __x;
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _Tp, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(list<_Tp, _Alloc>& __x, list<_Tp, _Alloc>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Tp, class _Allocator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY typename list<_Tp, _Allocator>::size_type
+erase_if(list<_Tp, _Allocator>& __c, _Predicate __pred) {
+  return __c.remove_if(__pred);
+}
+
+template <class _Tp, class _Allocator, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY typename list<_Tp, _Allocator>::size_type
+erase(list<_Tp, _Allocator>& __c, const _Up& __v) {
+  return _VSTD::erase_if(__c, [&](auto& __elem) { return __elem == __v; });
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_LIST
diff --git a/contrib/libs/cxxsupp/libcxx/include/locale b/contrib/libs/cxxsupp/libcxx/include/locale
new file mode 100644
index 00000000000..242790a9d45
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/locale
@@ -0,0 +1,4443 @@
+// -*- C++ -*-
+//===-------------------------- locale ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_LOCALE
+#define _LIBCPP_LOCALE
+
+/*
+    locale synopsis
+
+namespace std
+{
+
+class locale
+{
+public:
+    // types:
+    class facet;
+    class id;
+
+    typedef int category;
+    static const category // values assigned here are for exposition only
+        none     = 0x000,
+        collate  = 0x010,
+        ctype    = 0x020,
+        monetary = 0x040,
+        numeric  = 0x080,
+        time     = 0x100,
+        messages = 0x200,
+        all = collate | ctype | monetary | numeric | time | messages;
+
+    // construct/copy/destroy:
+    locale() noexcept;
+    locale(const locale& other) noexcept;
+    explicit locale(const char* std_name);
+    explicit locale(const string& std_name);
+    locale(const locale& other, const char* std_name, category);
+    locale(const locale& other, const string& std_name, category);
+    template <class Facet> locale(const locale& other, Facet* f);
+    locale(const locale& other, const locale& one, category);
+
+    ~locale(); // not virtual
+
+    const locale& operator=(const locale& other) noexcept;
+
+    template <class Facet> locale combine(const locale& other) const;
+
+    // locale operations:
+    basic_string<char> name() const;
+    bool operator==(const locale& other) const;
+    bool operator!=(const locale& other) const;
+    template <class charT, class Traits, class Allocator>
+      bool operator()(const basic_string<charT,Traits,Allocator>& s1,
+                      const basic_string<charT,Traits,Allocator>& s2) const;
+
+    // global locale objects:
+    static locale global(const locale&);
+    static const locale& classic();
+};
+
+template <class Facet> const Facet& use_facet(const locale&);
+template <class Facet> bool has_facet(const locale&) noexcept;
+
+// 22.3.3, convenience interfaces:
+template <class charT> bool isspace (charT c, const locale& loc);
+template <class charT> bool isprint (charT c, const locale& loc);
+template <class charT> bool iscntrl (charT c, const locale& loc);
+template <class charT> bool isupper (charT c, const locale& loc);
+template <class charT> bool islower (charT c, const locale& loc);
+template <class charT> bool isalpha (charT c, const locale& loc);
+template <class charT> bool isdigit (charT c, const locale& loc);
+template <class charT> bool ispunct (charT c, const locale& loc);
+template <class charT> bool isxdigit(charT c, const locale& loc);
+template <class charT> bool isalnum (charT c, const locale& loc);
+template <class charT> bool isgraph (charT c, const locale& loc);
+template <class charT> charT toupper(charT c, const locale& loc);
+template <class charT> charT tolower(charT c, const locale& loc);
+
+template<class Codecvt, class Elem = wchar_t,
+         class Wide_alloc = allocator<Elem>,
+         class Byte_alloc = allocator<char>>
+class wstring_convert
+{
+public:
+    typedef basic_string<char, char_traits<char>, Byte_alloc> byte_string;
+    typedef basic_string<Elem, char_traits<Elem>, Wide_alloc> wide_string;
+    typedef typename Codecvt::state_type                      state_type;
+    typedef typename wide_string::traits_type::int_type       int_type;
+
+    wstring_convert(Codecvt* pcvt = new Codecvt);          // before C++14
+    explicit wstring_convert(Codecvt* pcvt = new Codecvt); // before C++20
+    wstring_convert() : wstring_convert(new Codecvt) {}    // C++20
+    explicit wstring_convert(Codecvt* pcvt);               // C++20
+
+    wstring_convert(Codecvt* pcvt, state_type state);
+    explicit wstring_convert(const byte_string& byte_err,           // explicit in C++14
+                    const wide_string& wide_err = wide_string());
+    wstring_convert(const wstring_convert&) = delete;               // C++14
+    wstring_convert & operator=(const wstring_convert &) = delete;  // C++14
+    ~wstring_convert();
+
+    wide_string from_bytes(char byte);
+    wide_string from_bytes(const char* ptr);
+    wide_string from_bytes(const byte_string& str);
+    wide_string from_bytes(const char* first, const char* last);
+
+    byte_string to_bytes(Elem wchar);
+    byte_string to_bytes(const Elem* wptr);
+    byte_string to_bytes(const wide_string& wstr);
+    byte_string to_bytes(const Elem* first, const Elem* last);
+
+    size_t converted() const; // noexcept in C++14
+    state_type state() const;
+};
+
+template <class Codecvt, class Elem = wchar_t, class Tr = char_traits<Elem>>
+class wbuffer_convert
+    : public basic_streambuf<Elem, Tr>
+{
+public:
+    typedef typename Tr::state_type state_type;
+
+    wbuffer_convert(streambuf* bytebuf = 0, Codecvt* pcvt = new Codecvt,
+                    state_type state = state_type());          // before C++14
+    explicit wbuffer_convert(streambuf* bytebuf = nullptr, Codecvt* pcvt = new Codecvt,
+                            state_type state = state_type()); // before C++20
+    wbuffer_convert() : wbuffer_convert(nullptr) {} // C++20
+    explicit wbuffer_convert(streambuf* bytebuf, Codecvt* pcvt = new Codecvt,
+                            state_type state = state_type()); // C++20
+
+    wbuffer_convert(const wbuffer_convert&) = delete;               // C++14
+    wbuffer_convert & operator=(const wbuffer_convert &) = delete;  // C++14
+    ~wbuffer_convert();                                             // C++14
+
+    streambuf* rdbuf() const;
+    streambuf* rdbuf(streambuf* bytebuf);
+
+    state_type state() const;
+};
+
+// 22.4.1 and 22.4.1.3, ctype:
+class ctype_base;
+template <class charT> class ctype;
+template <> class ctype<char>; // specialization
+template <class charT> class ctype_byname;
+template <> class ctype_byname<char>; // specialization
+
+class codecvt_base;
+template <class internT, class externT, class stateT> class codecvt;
+template <class internT, class externT, class stateT> class codecvt_byname;
+
+// 22.4.2 and 22.4.3, numeric:
+template <class charT, class InputIterator> class num_get;
+template <class charT, class OutputIterator> class num_put;
+template <class charT> class numpunct;
+template <class charT> class numpunct_byname;
+
+// 22.4.4, col lation:
+template <class charT> class collate;
+template <class charT> class collate_byname;
+
+// 22.4.5, date and time:
+class time_base;
+template <class charT, class InputIterator> class time_get;
+template <class charT, class InputIterator> class time_get_byname;
+template <class charT, class OutputIterator> class time_put;
+template <class charT, class OutputIterator> class time_put_byname;
+
+// 22.4.6, money:
+class money_base;
+template <class charT, class InputIterator> class money_get;
+template <class charT, class OutputIterator> class money_put;
+template <class charT, bool Intl> class moneypunct;
+template <class charT, bool Intl> class moneypunct_byname;
+
+// 22.4.7, message retrieval:
+class messages_base;
+template <class charT> class messages;
+template <class charT> class messages_byname;
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__locale>
+#include <algorithm>
+#ifndef __APPLE__
+# include <cstdarg>
+#endif
+#include <cstdio>
+#include <cstdlib>
+#include <ctime>
+#include <ios>
+#include <iterator>
+#include <limits>
+#include <memory>
+#include <streambuf>
+#include <version>
+
+#if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__))
+// Most unix variants have catopen.  These are the specific ones that don't.
+#  if !defined(__BIONIC__) && !defined(_NEWLIB_VERSION)
+#    define _LIBCPP_HAS_CATOPEN 1
+#include <nl_types.h>
+#endif
+#endif
+
+#ifdef _LIBCPP_LOCALE__L_EXTENSIONS
+#include <__bsd_locale_defaults.h>
+#else
+#include <__bsd_locale_fallbacks.h>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if defined(__APPLE__) || defined(__FreeBSD__)
+#  define _LIBCPP_GET_C_LOCALE 0
+#elif defined(__NetBSD__)
+#  define _LIBCPP_GET_C_LOCALE LC_C_LOCALE
+#else
+#  define _LIBCPP_GET_C_LOCALE __cloc()
+   // Get the C locale object
+   _LIBCPP_FUNC_VIS locale_t __cloc();
+#define __cloc_defined
+#endif
+
+// __scan_keyword
+// Scans [__b, __e) until a match is found in the basic_strings range
+//  [__kb, __ke) or until it can be shown that there is no match in [__kb, __ke).
+//  __b will be incremented (visibly), consuming CharT until a match is found
+//  or proved to not exist.  A keyword may be "", in which will match anything.
+//  If one keyword is a prefix of another, and the next CharT in the input
+//  might match another keyword, the algorithm will attempt to find the longest
+//  matching keyword.  If the longer matching keyword ends up not matching, then
+//  no keyword match is found.  If no keyword match is found, __ke is returned
+//  and failbit is set in __err.
+//  Else an iterator pointing to the matching keyword is found.  If more than
+//  one keyword matches, an iterator to the first matching keyword is returned.
+//  If on exit __b == __e, eofbit is set in __err.  If __case_sensitive is false,
+//  __ct is used to force to lower case before comparing characters.
+//  Examples:
+//  Keywords:  "a", "abb"
+//  If the input is "a", the first keyword matches and eofbit is set.
+//  If the input is "abc", no match is found and "ab" are consumed.
+template <class _InputIterator, class _ForwardIterator, class _Ctype>
+_LIBCPP_HIDDEN
+_ForwardIterator
+__scan_keyword(_InputIterator& __b, _InputIterator __e,
+               _ForwardIterator __kb, _ForwardIterator __ke,
+               const _Ctype& __ct, ios_base::iostate& __err,
+               bool __case_sensitive = true)
+{
+    typedef typename iterator_traits<_InputIterator>::value_type _CharT;
+    size_t __nkw = static_cast<size_t>(_VSTD::distance(__kb, __ke));
+    const unsigned char __doesnt_match = '\0';
+    const unsigned char __might_match = '\1';
+    const unsigned char __does_match = '\2';
+    unsigned char __statbuf[100];
+    unsigned char* __status = __statbuf;
+    unique_ptr<unsigned char, void(*)(void*)> __stat_hold(nullptr, free);
+    if (__nkw > sizeof(__statbuf))
+    {
+        __status = (unsigned char*)malloc(__nkw);
+        if (__status == nullptr)
+            __throw_bad_alloc();
+        __stat_hold.reset(__status);
+    }
+    size_t __n_might_match = __nkw;  // At this point, any keyword might match
+    size_t __n_does_match = 0;       // but none of them definitely do
+    // Initialize all statuses to __might_match, except for "" keywords are __does_match
+    unsigned char* __st = __status;
+    for (_ForwardIterator __ky = __kb; __ky != __ke; ++__ky, (void) ++__st)
+    {
+        if (!__ky->empty())
+            *__st = __might_match;
+        else
+        {
+            *__st = __does_match;
+            --__n_might_match;
+            ++__n_does_match;
+        }
+    }
+    // While there might be a match, test keywords against the next CharT
+    for (size_t __indx = 0; __b != __e && __n_might_match > 0; ++__indx)
+    {
+        // Peek at the next CharT but don't consume it
+        _CharT __c = *__b;
+        if (!__case_sensitive)
+            __c = __ct.toupper(__c);
+        bool __consume = false;
+        // For each keyword which might match, see if the __indx character is __c
+        // If a match if found, consume __c
+        // If a match is found, and that is the last character in the keyword,
+        //    then that keyword matches.
+        // If the keyword doesn't match this character, then change the keyword
+        //    to doesn't match
+        __st = __status;
+        for (_ForwardIterator __ky = __kb; __ky != __ke; ++__ky, (void) ++__st)
+        {
+            if (*__st == __might_match)
+            {
+                _CharT __kc = (*__ky)[__indx];
+                if (!__case_sensitive)
+                    __kc = __ct.toupper(__kc);
+                if (__c == __kc)
+                {
+                    __consume = true;
+                    if (__ky->size() == __indx+1)
+                    {
+                        *__st = __does_match;
+                        --__n_might_match;
+                        ++__n_does_match;
+                    }
+                }
+                else
+                {
+                    *__st = __doesnt_match;
+                    --__n_might_match;
+                }
+            }
+        }
+        // consume if we matched a character
+        if (__consume)
+        {
+            ++__b;
+            // If we consumed a character and there might be a matched keyword that
+            //   was marked matched on a previous iteration, then such keywords
+            //   which are now marked as not matching.
+            if (__n_might_match + __n_does_match > 1)
+            {
+                __st = __status;
+                for (_ForwardIterator __ky = __kb; __ky != __ke; ++__ky, (void) ++__st)
+                {
+                    if (*__st == __does_match && __ky->size() != __indx+1)
+                    {
+                        *__st = __doesnt_match;
+                        --__n_does_match;
+                    }
+                }
+            }
+        }
+    }
+    // We've exited the loop because we hit eof and/or we have no more "might matches".
+    if (__b == __e)
+        __err |= ios_base::eofbit;
+    // Return the first matching result
+    for (__st = __status; __kb != __ke; ++__kb, (void) ++__st)
+        if (*__st == __does_match)
+            break;
+    if (__kb == __ke)
+        __err |= ios_base::failbit;
+    return __kb;
+}
+
+struct _LIBCPP_TYPE_VIS __num_get_base
+{
+    static const int __num_get_buf_sz = 40;
+
+    static int __get_base(ios_base&);
+    static const char __src[33];
+};
+
+_LIBCPP_FUNC_VIS
+void __check_grouping(const string& __grouping, unsigned* __g, unsigned* __g_end,
+                      ios_base::iostate& __err);
+
+template <class _CharT>
+struct __num_get
+    : protected __num_get_base
+{
+    static string __stage2_float_prep(ios_base& __iob, _CharT* __atoms, _CharT& __decimal_point,
+                                      _CharT& __thousands_sep);
+
+    static int __stage2_float_loop(_CharT __ct, bool& __in_units, char& __exp,
+                                   char* __a, char*& __a_end,
+                                   _CharT __decimal_point, _CharT __thousands_sep,
+                                   const string& __grouping, unsigned* __g,
+                                   unsigned*& __g_end, unsigned& __dc, _CharT* __atoms);
+#ifndef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
+    static string __stage2_int_prep(ios_base& __iob, _CharT* __atoms, _CharT& __thousands_sep);
+    static int __stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
+                  unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
+                  unsigned* __g, unsigned*& __g_end, _CharT* __atoms);
+
+#else
+    static string __stage2_int_prep(ios_base& __iob, _CharT& __thousands_sep)
+    {
+        locale __loc = __iob.getloc();
+        const numpunct<_CharT>& __np = use_facet<numpunct<_CharT> >(__loc);
+        __thousands_sep = __np.thousands_sep();
+        return __np.grouping();
+    }
+
+    const _CharT* __do_widen(ios_base& __iob, _CharT* __atoms) const
+    {
+      return __do_widen_p(__iob, __atoms);
+    }
+
+
+    static int __stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
+                  unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
+                  unsigned* __g, unsigned*& __g_end, const _CharT* __atoms);
+private:
+    template<typename T>
+    const T* __do_widen_p(ios_base& __iob, T* __atoms) const
+    {
+      locale __loc = __iob.getloc();
+      use_facet<ctype<T> >(__loc).widen(__src, __src + 26, __atoms);
+      return __atoms;
+    }
+
+    const char* __do_widen_p(ios_base& __iob, char* __atoms) const
+    {
+      (void)__iob;
+      (void)__atoms;
+      return __src;
+    }
+#endif
+};
+
+#ifndef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
+template <class _CharT>
+string
+__num_get<_CharT>::__stage2_int_prep(ios_base& __iob, _CharT* __atoms, _CharT& __thousands_sep)
+{
+    locale __loc = __iob.getloc();
+    use_facet<ctype<_CharT> >(__loc).widen(__src, __src + 26, __atoms);
+    const numpunct<_CharT>& __np = use_facet<numpunct<_CharT> >(__loc);
+    __thousands_sep = __np.thousands_sep();
+    return __np.grouping();
+}
+#endif
+
+template <class _CharT>
+string
+__num_get<_CharT>::__stage2_float_prep(ios_base& __iob, _CharT* __atoms, _CharT& __decimal_point,
+                    _CharT& __thousands_sep)
+{
+    locale __loc = __iob.getloc();
+    use_facet<ctype<_CharT> >(__loc).widen(__src, __src + 32, __atoms);
+    const numpunct<_CharT>& __np = use_facet<numpunct<_CharT> >(__loc);
+    __decimal_point = __np.decimal_point();
+    __thousands_sep = __np.thousands_sep();
+    return __np.grouping();
+}
+
+template <class _CharT>
+int
+#ifndef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
+__num_get<_CharT>::__stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
+                  unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
+                  unsigned* __g, unsigned*& __g_end, _CharT* __atoms)
+#else
+__num_get<_CharT>::__stage2_int_loop(_CharT __ct, int __base, char* __a, char*& __a_end,
+                  unsigned& __dc, _CharT __thousands_sep, const string& __grouping,
+                  unsigned* __g, unsigned*& __g_end, const _CharT* __atoms)
+
+#endif
+{
+    if (__a_end == __a && (__ct == __atoms[24] || __ct == __atoms[25]))
+    {
+        *__a_end++ = __ct == __atoms[24] ? '+' : '-';
+        __dc = 0;
+        return 0;
+    }
+    if (__grouping.size() != 0 && __ct == __thousands_sep)
+    {
+        if (__g_end-__g < __num_get_buf_sz)
+        {
+            *__g_end++ = __dc;
+            __dc = 0;
+        }
+        return 0;
+    }
+    ptrdiff_t __f = find(__atoms, __atoms + 26, __ct) - __atoms;
+    if (__f >= 24)
+        return -1;
+    switch (__base)
+    {
+    case 8:
+    case 10:
+        if (__f >= __base)
+            return -1;
+        break;
+    case 16:
+        if (__f < 22)
+            break;
+        if (__a_end != __a && __a_end - __a <= 2 && __a_end[-1] == '0')
+        {
+            __dc = 0;
+            *__a_end++ = __src[__f];
+            return 0;
+        }
+        return -1;
+    }
+    *__a_end++ = __src[__f];
+    ++__dc;
+    return 0;
+}
+
+template <class _CharT>
+int
+__num_get<_CharT>::__stage2_float_loop(_CharT __ct, bool& __in_units, char& __exp, char* __a, char*& __a_end,
+                    _CharT __decimal_point, _CharT __thousands_sep, const string& __grouping,
+                    unsigned* __g, unsigned*& __g_end, unsigned& __dc, _CharT* __atoms)
+{
+    if (__ct == __decimal_point)
+    {
+        if (!__in_units)
+            return -1;
+        __in_units = false;
+        *__a_end++ = '.';
+        if (__grouping.size() != 0 && __g_end-__g < __num_get_buf_sz)
+            *__g_end++ = __dc;
+        return 0;
+    }
+    if (__ct == __thousands_sep && __grouping.size() != 0)
+    {
+        if (!__in_units)
+            return -1;
+        if (__g_end-__g < __num_get_buf_sz)
+        {
+            *__g_end++ = __dc;
+            __dc = 0;
+        }
+        return 0;
+    }
+    ptrdiff_t __f = find(__atoms, __atoms + 32, __ct) - __atoms;
+    if (__f >= 32)
+        return -1;
+    char __x = __src[__f];
+    if (__x == '-' || __x == '+')
+    {
+        if (__a_end == __a || (__a_end[-1] & 0x5F) == (__exp & 0x7F))
+        {
+            *__a_end++ = __x;
+            return 0;
+        }
+        return -1;
+    }
+    if (__x == 'x' || __x == 'X')
+        __exp = 'P';
+    else if ((__x & 0x5F) == __exp)
+    {
+        __exp |= (char) 0x80;
+        if (__in_units)
+        {
+            __in_units = false;
+            if (__grouping.size() != 0 && __g_end-__g < __num_get_buf_sz)
+                *__g_end++ = __dc;
+        }
+    }
+    *__a_end++ = __x;
+    if (__f >= 22)
+        return 0;
+    ++__dc;
+    return 0;
+}
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(struct _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __num_get<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(struct _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __num_get<wchar_t>)
+#endif
+
+template <class _CharT, class _InputIterator = istreambuf_iterator<_CharT> >
+class _LIBCPP_TEMPLATE_VIS num_get
+    : public locale::facet,
+      private __num_get<_CharT>
+{
+public:
+    typedef _CharT char_type;
+    typedef _InputIterator iter_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit num_get(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, ios_base& __iob,
+                  ios_base::iostate& __err, bool& __v) const
+    {
+        return do_get(__b, __e, __iob, __err, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, ios_base& __iob,
+                  ios_base::iostate& __err, long& __v) const
+    {
+        return do_get(__b, __e, __iob, __err, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, ios_base& __iob,
+                  ios_base::iostate& __err, long long& __v) const
+    {
+        return do_get(__b, __e, __iob, __err, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, ios_base& __iob,
+                  ios_base::iostate& __err, unsigned short& __v) const
+    {
+        return do_get(__b, __e, __iob, __err, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, ios_base& __iob,
+                  ios_base::iostate& __err, unsigned int& __v) const
+    {
+        return do_get(__b, __e, __iob, __err, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, ios_base& __iob,
+                  ios_base::iostate& __err, unsigned long& __v) const
+    {
+        return do_get(__b, __e, __iob, __err, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, ios_base& __iob,
+                  ios_base::iostate& __err, unsigned long long& __v) const
+    {
+        return do_get(__b, __e, __iob, __err, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, ios_base& __iob,
+                  ios_base::iostate& __err, float& __v) const
+    {
+        return do_get(__b, __e, __iob, __err, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, ios_base& __iob,
+                  ios_base::iostate& __err, double& __v) const
+    {
+        return do_get(__b, __e, __iob, __err, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, ios_base& __iob,
+                  ios_base::iostate& __err, long double& __v) const
+    {
+        return do_get(__b, __e, __iob, __err, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, ios_base& __iob,
+                  ios_base::iostate& __err, void*& __v) const
+    {
+        return do_get(__b, __e, __iob, __err, __v);
+    }
+
+    static locale::id id;
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    ~num_get() {}
+
+    template <class _Fp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    iter_type __do_get_floating_point
+                            (iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, _Fp& __v) const;
+
+    template <class _Signed>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    iter_type __do_get_signed
+                            (iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, _Signed& __v) const;
+
+    template <class _Unsigned>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    iter_type __do_get_unsigned
+                            (iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, _Unsigned& __v) const;
+
+
+    virtual iter_type do_get(iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, bool& __v) const;
+
+    virtual iter_type do_get(iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, long& __v) const
+    { return this->__do_get_signed ( __b, __e, __iob, __err, __v ); }
+
+    virtual iter_type do_get(iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, long long& __v) const
+    { return this->__do_get_signed ( __b, __e, __iob, __err, __v ); }
+
+    virtual iter_type do_get(iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, unsigned short& __v) const
+    { return this->__do_get_unsigned ( __b, __e, __iob, __err, __v ); }
+
+    virtual iter_type do_get(iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, unsigned int& __v) const
+    { return this->__do_get_unsigned ( __b, __e, __iob, __err, __v ); }
+
+    virtual iter_type do_get(iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, unsigned long& __v) const
+    { return this->__do_get_unsigned ( __b, __e, __iob, __err, __v ); }
+
+    virtual iter_type do_get(iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, unsigned long long& __v) const
+    { return this->__do_get_unsigned ( __b, __e, __iob, __err, __v ); }
+
+    virtual iter_type do_get(iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, float& __v) const
+    { return this->__do_get_floating_point ( __b, __e, __iob, __err, __v ); }
+
+    virtual iter_type do_get(iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, double& __v) const
+    { return this->__do_get_floating_point ( __b, __e, __iob, __err, __v ); }
+
+    virtual iter_type do_get(iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, long double& __v) const
+    { return this->__do_get_floating_point ( __b, __e, __iob, __err, __v ); }
+
+    virtual iter_type do_get(iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, void*& __v) const;
+};
+
+template <class _CharT, class _InputIterator>
+locale::id
+num_get<_CharT, _InputIterator>::id;
+
+template <class _Tp>
+_LIBCPP_HIDDEN _Tp
+__num_get_signed_integral(const char* __a, const char* __a_end,
+                          ios_base::iostate& __err, int __base)
+{
+    if (__a != __a_end)
+    {
+        typename remove_reference<decltype(errno)>::type __save_errno = errno;
+        errno = 0;
+        char *__p2;
+        long long __ll = strtoll_l(__a, &__p2, __base, _LIBCPP_GET_C_LOCALE);
+        typename remove_reference<decltype(errno)>::type __current_errno = errno;
+        if (__current_errno == 0)
+            errno = __save_errno;
+        if (__p2 != __a_end)
+        {
+            __err = ios_base::failbit;
+            return 0;
+        }
+        else if (__current_errno == ERANGE         ||
+                 __ll < numeric_limits<_Tp>::min() ||
+                 numeric_limits<_Tp>::max() < __ll)
+        {
+            __err = ios_base::failbit;
+            if (__ll > 0)
+                return numeric_limits<_Tp>::max();
+            else
+                return numeric_limits<_Tp>::min();
+        }
+        return static_cast<_Tp>(__ll);
+    }
+    __err = ios_base::failbit;
+    return 0;
+}
+
+template <class _Tp>
+_LIBCPP_HIDDEN _Tp
+__num_get_unsigned_integral(const char* __a, const char* __a_end,
+                            ios_base::iostate& __err, int __base)
+{
+    if (__a != __a_end)
+    {
+        const bool __negate = *__a == '-';
+        if (__negate && ++__a == __a_end) {
+          __err = ios_base::failbit;
+          return 0;
+        }
+        typename remove_reference<decltype(errno)>::type __save_errno = errno;
+        errno = 0;
+        char *__p2;
+        unsigned long long __ll = strtoull_l(__a, &__p2, __base, _LIBCPP_GET_C_LOCALE);
+        typename remove_reference<decltype(errno)>::type __current_errno = errno;
+        if (__current_errno == 0)
+            errno = __save_errno;
+        if (__p2 != __a_end)
+        {
+            __err = ios_base::failbit;
+            return 0;
+        }
+        else if (__current_errno == ERANGE || numeric_limits<_Tp>::max() < __ll)
+        {
+            __err = ios_base::failbit;
+            return numeric_limits<_Tp>::max();
+        }
+        _Tp __res = static_cast<_Tp>(__ll);
+        if (__negate) __res = -__res;
+        return __res;
+    }
+    __err = ios_base::failbit;
+    return 0;
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp __do_strtod(const char* __a, char** __p2);
+
+template <>
+inline _LIBCPP_INLINE_VISIBILITY
+float __do_strtod<float>(const char* __a, char** __p2) {
+    return strtof_l(__a, __p2, _LIBCPP_GET_C_LOCALE);
+}
+
+template <>
+inline _LIBCPP_INLINE_VISIBILITY
+double __do_strtod<double>(const char* __a, char** __p2) {
+    return strtod_l(__a, __p2, _LIBCPP_GET_C_LOCALE);
+}
+
+template <>
+inline _LIBCPP_INLINE_VISIBILITY
+long double __do_strtod<long double>(const char* __a, char** __p2) {
+    return strtold_l(__a, __p2, _LIBCPP_GET_C_LOCALE);
+}
+
+template <class _Tp>
+_LIBCPP_HIDDEN
+_Tp
+__num_get_float(const char* __a, const char* __a_end, ios_base::iostate& __err)
+{
+    if (__a != __a_end)
+    {
+        typename remove_reference<decltype(errno)>::type __save_errno = errno;
+        errno = 0;
+        char *__p2;
+        _Tp __ld = __do_strtod<_Tp>(__a, &__p2);
+        typename remove_reference<decltype(errno)>::type __current_errno = errno;
+        if (__current_errno == 0)
+            errno = __save_errno;
+        if (__p2 != __a_end)
+        {
+            __err = ios_base::failbit;
+            return 0;
+        }
+        else if (__current_errno == ERANGE)
+            __err = ios_base::failbit;
+        return __ld;
+    }
+    __err = ios_base::failbit;
+    return 0;
+}
+
+template <class _CharT, class _InputIterator>
+_InputIterator
+num_get<_CharT, _InputIterator>::do_get(iter_type __b, iter_type __e,
+                                        ios_base& __iob,
+                                        ios_base::iostate& __err,
+                                        bool& __v) const
+{
+    if ((__iob.flags() & ios_base::boolalpha) == 0)
+    {
+        long __lv = -1;
+        __b = do_get(__b, __e, __iob, __err, __lv);
+        switch (__lv)
+        {
+        case 0:
+            __v = false;
+            break;
+        case 1:
+            __v = true;
+            break;
+        default:
+            __v = true;
+            __err = ios_base::failbit;
+            break;
+        }
+        return __b;
+    }
+    const ctype<_CharT>& __ct = use_facet<ctype<_CharT> >(__iob.getloc());
+    const numpunct<_CharT>& __np = use_facet<numpunct<_CharT> >(__iob.getloc());
+    typedef typename numpunct<_CharT>::string_type string_type;
+    const string_type __names[2] = {__np.truename(), __np.falsename()};
+    const string_type* __i = _VSTD::__scan_keyword(__b, __e, __names, __names+2,
+                                                   __ct, __err);
+    __v = __i == __names;
+    return __b;
+}
+
+// signed
+
+template <class _CharT, class _InputIterator>
+template <class _Signed>
+_InputIterator
+num_get<_CharT, _InputIterator>::__do_get_signed(iter_type __b, iter_type __e,
+                                        ios_base& __iob,
+                                        ios_base::iostate& __err,
+                                        _Signed& __v) const
+{
+    // Stage 1
+    int __base = this->__get_base(__iob);
+    // Stage 2
+    char_type __thousands_sep;
+    const int __atoms_size = 26;
+#ifdef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
+    char_type __atoms1[__atoms_size];
+    const char_type *__atoms = this->__do_widen(__iob, __atoms1);
+    string __grouping = this->__stage2_int_prep(__iob, __thousands_sep);
+#else
+    char_type __atoms[__atoms_size];
+    string __grouping = this->__stage2_int_prep(__iob, __atoms, __thousands_sep);
+#endif
+    string __buf;
+    __buf.resize(__buf.capacity());
+    char* __a = &__buf[0];
+    char* __a_end = __a;
+    unsigned __g[__num_get_base::__num_get_buf_sz];
+    unsigned* __g_end = __g;
+    unsigned __dc = 0;
+    for (; __b != __e; ++__b)
+    {
+        if (__a_end == __a + __buf.size())
+        {
+            size_t __tmp = __buf.size();
+            __buf.resize(2*__buf.size());
+            __buf.resize(__buf.capacity());
+            __a = &__buf[0];
+            __a_end = __a + __tmp;
+        }
+        if (this->__stage2_int_loop(*__b, __base, __a, __a_end, __dc,
+                                    __thousands_sep, __grouping, __g, __g_end,
+                                    __atoms))
+            break;
+    }
+    if (__grouping.size() != 0 && __g_end-__g < __num_get_base::__num_get_buf_sz)
+        *__g_end++ = __dc;
+    // Stage 3
+    __v = __num_get_signed_integral<_Signed>(__a, __a_end, __err, __base);
+    // Digit grouping checked
+    __check_grouping(__grouping, __g, __g_end, __err);
+    // EOF checked
+    if (__b == __e)
+        __err |= ios_base::eofbit;
+    return __b;
+}
+
+// unsigned
+
+template <class _CharT, class _InputIterator>
+template <class _Unsigned>
+_InputIterator
+num_get<_CharT, _InputIterator>::__do_get_unsigned(iter_type __b, iter_type __e,
+                                        ios_base& __iob,
+                                        ios_base::iostate& __err,
+                                        _Unsigned& __v) const
+{
+    // Stage 1
+    int __base = this->__get_base(__iob);
+    // Stage 2
+    char_type __thousands_sep;
+    const int __atoms_size = 26;
+#ifdef _LIBCPP_ABI_OPTIMIZED_LOCALE_NUM_GET
+    char_type __atoms1[__atoms_size];
+    const char_type *__atoms = this->__do_widen(__iob, __atoms1);
+    string __grouping = this->__stage2_int_prep(__iob, __thousands_sep);
+#else
+    char_type __atoms[__atoms_size];
+    string __grouping = this->__stage2_int_prep(__iob, __atoms, __thousands_sep);
+#endif
+    string __buf;
+    __buf.resize(__buf.capacity());
+    char* __a = &__buf[0];
+    char* __a_end = __a;
+    unsigned __g[__num_get_base::__num_get_buf_sz];
+    unsigned* __g_end = __g;
+    unsigned __dc = 0;
+    for (; __b != __e; ++__b)
+    {
+        if (__a_end == __a + __buf.size())
+        {
+            size_t __tmp = __buf.size();
+            __buf.resize(2*__buf.size());
+            __buf.resize(__buf.capacity());
+            __a = &__buf[0];
+            __a_end = __a + __tmp;
+        }
+        if (this->__stage2_int_loop(*__b, __base, __a, __a_end, __dc,
+                                    __thousands_sep, __grouping, __g, __g_end,
+                                    __atoms))
+            break;
+    }
+    if (__grouping.size() != 0 && __g_end-__g < __num_get_base::__num_get_buf_sz)
+        *__g_end++ = __dc;
+    // Stage 3
+    __v = __num_get_unsigned_integral<_Unsigned>(__a, __a_end, __err, __base);
+    // Digit grouping checked
+    __check_grouping(__grouping, __g, __g_end, __err);
+    // EOF checked
+    if (__b == __e)
+        __err |= ios_base::eofbit;
+    return __b;
+}
+
+// floating point
+
+template <class _CharT, class _InputIterator>
+template <class _Fp>
+_InputIterator
+num_get<_CharT, _InputIterator>::__do_get_floating_point(iter_type __b, iter_type __e,
+                                        ios_base& __iob,
+                                        ios_base::iostate& __err,
+                                        _Fp& __v) const
+{
+    // Stage 1, nothing to do
+    // Stage 2
+    char_type __atoms[32];
+    char_type __decimal_point;
+    char_type __thousands_sep;
+    string __grouping = this->__stage2_float_prep(__iob, __atoms,
+                                                  __decimal_point,
+                                                  __thousands_sep);
+    string __buf;
+    __buf.resize(__buf.capacity());
+    char* __a = &__buf[0];
+    char* __a_end = __a;
+    unsigned __g[__num_get_base::__num_get_buf_sz];
+    unsigned* __g_end = __g;
+    unsigned __dc = 0;
+    bool __in_units = true;
+    char __exp = 'E';
+    for (; __b != __e; ++__b)
+    {
+        if (__a_end == __a + __buf.size())
+        {
+            size_t __tmp = __buf.size();
+            __buf.resize(2*__buf.size());
+            __buf.resize(__buf.capacity());
+            __a = &__buf[0];
+            __a_end = __a + __tmp;
+        }
+        if (this->__stage2_float_loop(*__b, __in_units, __exp, __a, __a_end,
+                                      __decimal_point, __thousands_sep,
+                                      __grouping, __g, __g_end,
+                                      __dc, __atoms))
+            break;
+    }
+    if (__grouping.size() != 0 && __in_units && __g_end-__g < __num_get_base::__num_get_buf_sz)
+        *__g_end++ = __dc;
+    // Stage 3
+    __v = __num_get_float<_Fp>(__a, __a_end, __err);
+    // Digit grouping checked
+    __check_grouping(__grouping, __g, __g_end, __err);
+    // EOF checked
+    if (__b == __e)
+        __err |= ios_base::eofbit;
+    return __b;
+}
+
+template <class _CharT, class _InputIterator>
+_InputIterator
+num_get<_CharT, _InputIterator>::do_get(iter_type __b, iter_type __e,
+                                        ios_base& __iob,
+                                        ios_base::iostate& __err,
+                                        void*& __v) const
+{
+    // Stage 1
+    int __base = 16;
+    // Stage 2
+    char_type __atoms[26];
+    char_type __thousands_sep = 0;
+    string __grouping;
+    use_facet<ctype<_CharT> >(__iob.getloc()).widen(__num_get_base::__src,
+                                                    __num_get_base::__src + 26, __atoms);
+    string __buf;
+    __buf.resize(__buf.capacity());
+    char* __a = &__buf[0];
+    char* __a_end = __a;
+    unsigned __g[__num_get_base::__num_get_buf_sz];
+    unsigned* __g_end = __g;
+    unsigned __dc = 0;
+    for (; __b != __e; ++__b)
+    {
+        if (__a_end == __a + __buf.size())
+        {
+            size_t __tmp = __buf.size();
+            __buf.resize(2*__buf.size());
+            __buf.resize(__buf.capacity());
+            __a = &__buf[0];
+            __a_end = __a + __tmp;
+        }
+        if (this->__stage2_int_loop(*__b, __base, __a, __a_end, __dc,
+                                    __thousands_sep, __grouping,
+                                    __g, __g_end, __atoms))
+            break;
+    }
+    // Stage 3
+    __buf.resize(__a_end - __a);
+    if (__libcpp_sscanf_l(__buf.c_str(), _LIBCPP_GET_C_LOCALE, "%p", &__v) != 1)
+        __err = ios_base::failbit;
+    // EOF checked
+    if (__b == __e)
+        __err |= ios_base::eofbit;
+    return __b;
+}
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS num_get<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS num_get<wchar_t>)
+#endif
+
+struct _LIBCPP_TYPE_VIS __num_put_base
+{
+protected:
+    static void __format_int(char* __fmt, const char* __len, bool __signd,
+                             ios_base::fmtflags __flags);
+    static bool __format_float(char* __fmt, const char* __len,
+                               ios_base::fmtflags __flags);
+    static char* __identify_padding(char* __nb, char* __ne,
+                                    const ios_base& __iob);
+};
+
+template <class _CharT>
+struct __num_put
+    : protected __num_put_base
+{
+    static void __widen_and_group_int(char* __nb, char* __np, char* __ne,
+                                      _CharT* __ob, _CharT*& __op, _CharT*& __oe,
+                                      const locale& __loc);
+    static void __widen_and_group_float(char* __nb, char* __np, char* __ne,
+                                        _CharT* __ob, _CharT*& __op, _CharT*& __oe,
+                                        const locale& __loc);
+};
+
+template <class _CharT>
+void
+__num_put<_CharT>::__widen_and_group_int(char* __nb, char* __np, char* __ne,
+                                         _CharT* __ob, _CharT*& __op, _CharT*& __oe,
+                                         const locale& __loc)
+{
+    const ctype<_CharT>&    __ct = use_facet<ctype<_CharT> >   (__loc);
+    const numpunct<_CharT>& __npt = use_facet<numpunct<_CharT> >(__loc);
+    string __grouping = __npt.grouping();
+    if (__grouping.empty())
+    {
+        __ct.widen(__nb, __ne, __ob);
+        __oe = __ob + (__ne - __nb);
+    }
+    else
+    {
+        __oe = __ob;
+        char* __nf = __nb;
+        if (*__nf == '-' || *__nf == '+')
+            *__oe++ = __ct.widen(*__nf++);
+        if (__ne - __nf >= 2 && __nf[0] == '0' && (__nf[1] == 'x' ||
+                                                   __nf[1] == 'X'))
+        {
+            *__oe++ = __ct.widen(*__nf++);
+            *__oe++ = __ct.widen(*__nf++);
+        }
+        reverse(__nf, __ne);
+        _CharT __thousands_sep = __npt.thousands_sep();
+        unsigned __dc = 0;
+        unsigned __dg = 0;
+        for (char* __p = __nf; __p < __ne; ++__p)
+        {
+            if (static_cast<unsigned>(__grouping[__dg]) > 0 &&
+                __dc == static_cast<unsigned>(__grouping[__dg]))
+            {
+                *__oe++ = __thousands_sep;
+                __dc = 0;
+                if (__dg < __grouping.size()-1)
+                    ++__dg;
+            }
+            *__oe++ = __ct.widen(*__p);
+            ++__dc;
+        }
+        reverse(__ob + (__nf - __nb), __oe);
+    }
+    if (__np == __ne)
+        __op = __oe;
+    else
+        __op = __ob + (__np - __nb);
+}
+
+template <class _CharT>
+void
+__num_put<_CharT>::__widen_and_group_float(char* __nb, char* __np, char* __ne,
+                                           _CharT* __ob, _CharT*& __op, _CharT*& __oe,
+                                           const locale& __loc)
+{
+    const ctype<_CharT>&    __ct = use_facet<ctype<_CharT> >   (__loc);
+    const numpunct<_CharT>& __npt = use_facet<numpunct<_CharT> >(__loc);
+    string __grouping = __npt.grouping();
+    __oe = __ob;
+    char* __nf = __nb;
+    if (*__nf == '-' || *__nf == '+')
+        *__oe++ = __ct.widen(*__nf++);
+    char* __ns;
+    if (__ne - __nf >= 2 && __nf[0] == '0' && (__nf[1] == 'x' ||
+                                               __nf[1] == 'X'))
+    {
+        *__oe++ = __ct.widen(*__nf++);
+        *__oe++ = __ct.widen(*__nf++);
+        for (__ns = __nf; __ns < __ne; ++__ns)
+            if (!isxdigit_l(*__ns, _LIBCPP_GET_C_LOCALE))
+                break;
+    }
+    else
+    {
+        for (__ns = __nf; __ns < __ne; ++__ns)
+            if (!isdigit_l(*__ns, _LIBCPP_GET_C_LOCALE))
+                break;
+    }
+    if (__grouping.empty())
+    {
+        __ct.widen(__nf, __ns, __oe);
+        __oe += __ns - __nf;
+    }
+    else
+    {
+        reverse(__nf, __ns);
+        _CharT __thousands_sep = __npt.thousands_sep();
+        unsigned __dc = 0;
+        unsigned __dg = 0;
+        for (char* __p = __nf; __p < __ns; ++__p)
+        {
+            if (__grouping[__dg] > 0 && __dc == static_cast<unsigned>(__grouping[__dg]))
+            {
+                *__oe++ = __thousands_sep;
+                __dc = 0;
+                if (__dg < __grouping.size()-1)
+                    ++__dg;
+            }
+            *__oe++ = __ct.widen(*__p);
+            ++__dc;
+        }
+        reverse(__ob + (__nf - __nb), __oe);
+    }
+    for (__nf = __ns; __nf < __ne; ++__nf)
+    {
+        if (*__nf == '.')
+        {
+            *__oe++ = __npt.decimal_point();
+            ++__nf;
+            break;
+        }
+        else
+            *__oe++ = __ct.widen(*__nf);
+    }
+    __ct.widen(__nf, __ne, __oe);
+    __oe += __ne - __nf;
+    if (__np == __ne)
+        __op = __oe;
+    else
+        __op = __ob + (__np - __nb);
+}
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(struct _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __num_put<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(struct _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __num_put<wchar_t>)
+#endif
+
+template <class _CharT, class _OutputIterator = ostreambuf_iterator<_CharT> >
+class _LIBCPP_TEMPLATE_VIS num_put
+    : public locale::facet,
+      private __num_put<_CharT>
+{
+public:
+    typedef _CharT char_type;
+    typedef _OutputIterator iter_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit num_put(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type put(iter_type __s, ios_base& __iob, char_type __fl,
+                  bool __v) const
+    {
+        return do_put(__s, __iob, __fl, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type put(iter_type __s, ios_base& __iob, char_type __fl,
+                  long __v) const
+    {
+        return do_put(__s, __iob, __fl, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type put(iter_type __s, ios_base& __iob, char_type __fl,
+                  long long __v) const
+    {
+        return do_put(__s, __iob, __fl, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type put(iter_type __s, ios_base& __iob, char_type __fl,
+                  unsigned long __v) const
+    {
+        return do_put(__s, __iob, __fl, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type put(iter_type __s, ios_base& __iob, char_type __fl,
+                  unsigned long long __v) const
+    {
+        return do_put(__s, __iob, __fl, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type put(iter_type __s, ios_base& __iob, char_type __fl,
+                  double __v) const
+    {
+        return do_put(__s, __iob, __fl, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type put(iter_type __s, ios_base& __iob, char_type __fl,
+                  long double __v) const
+    {
+        return do_put(__s, __iob, __fl, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type put(iter_type __s, ios_base& __iob, char_type __fl,
+                  const void* __v) const
+    {
+        return do_put(__s, __iob, __fl, __v);
+    }
+
+    static locale::id id;
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    ~num_put() {}
+
+    virtual iter_type do_put(iter_type __s, ios_base& __iob, char_type __fl,
+                             bool __v) const;
+    virtual iter_type do_put(iter_type __s, ios_base& __iob, char_type __fl,
+                             long __v) const;
+    virtual iter_type do_put(iter_type __s, ios_base& __iob, char_type __fl,
+                             long long __v) const;
+    virtual iter_type do_put(iter_type __s, ios_base& __iob, char_type __fl,
+                             unsigned long) const;
+    virtual iter_type do_put(iter_type __s, ios_base& __iob, char_type __fl,
+                             unsigned long long) const;
+    virtual iter_type do_put(iter_type __s, ios_base& __iob, char_type __fl,
+                             double __v) const;
+    virtual iter_type do_put(iter_type __s, ios_base& __iob, char_type __fl,
+                             long double __v) const;
+    virtual iter_type do_put(iter_type __s, ios_base& __iob, char_type __fl,
+                             const void* __v) const;
+};
+
+template <class _CharT, class _OutputIterator>
+locale::id
+num_put<_CharT, _OutputIterator>::id;
+
+template <class _CharT, class _OutputIterator>
+_LIBCPP_HIDDEN
+_OutputIterator
+__pad_and_output(_OutputIterator __s,
+                 const _CharT* __ob, const _CharT* __op, const _CharT* __oe,
+                 ios_base& __iob, _CharT __fl)
+{
+    streamsize __sz = __oe - __ob;
+    streamsize __ns = __iob.width();
+    if (__ns > __sz)
+        __ns -= __sz;
+    else
+        __ns = 0;
+    for (;__ob < __op; ++__ob, ++__s)
+        *__s = *__ob;
+    for (; __ns; --__ns, ++__s)
+        *__s = __fl;
+    for (; __ob < __oe; ++__ob, ++__s)
+        *__s = *__ob;
+    __iob.width(0);
+    return __s;
+}
+
+template <class _CharT, class _Traits>
+_LIBCPP_HIDDEN
+ostreambuf_iterator<_CharT, _Traits>
+__pad_and_output(ostreambuf_iterator<_CharT, _Traits> __s,
+                 const _CharT* __ob, const _CharT* __op, const _CharT* __oe,
+                 ios_base& __iob, _CharT __fl)
+{
+    if (__s.__sbuf_ == nullptr)
+        return __s;
+    streamsize __sz = __oe - __ob;
+    streamsize __ns = __iob.width();
+    if (__ns > __sz)
+        __ns -= __sz;
+    else
+        __ns = 0;
+    streamsize __np = __op - __ob;
+    if (__np > 0)
+    {
+        if (__s.__sbuf_->sputn(__ob, __np) != __np)
+        {
+            __s.__sbuf_ = nullptr;
+            return __s;
+        }
+    }
+    if (__ns > 0)
+    {
+        basic_string<_CharT, _Traits> __sp(__ns, __fl);
+        if (__s.__sbuf_->sputn(__sp.data(), __ns) != __ns)
+        {
+            __s.__sbuf_ = nullptr;
+            return __s;
+        }
+    }
+    __np = __oe - __op;
+    if (__np > 0)
+    {
+        if (__s.__sbuf_->sputn(__op, __np) != __np)
+        {
+            __s.__sbuf_ = nullptr;
+            return __s;
+        }
+    }
+    __iob.width(0);
+    return __s;
+}
+
+template <class _CharT, class _OutputIterator>
+_OutputIterator
+num_put<_CharT, _OutputIterator>::do_put(iter_type __s, ios_base& __iob,
+                                         char_type __fl, bool __v) const
+{
+    if ((__iob.flags() & ios_base::boolalpha) == 0)
+        return do_put(__s, __iob, __fl, (unsigned long)__v);
+    const numpunct<char_type>& __np = use_facet<numpunct<char_type> >(__iob.getloc());
+    typedef typename numpunct<char_type>::string_type string_type;
+#if _LIBCPP_DEBUG_LEVEL == 2
+    string_type __tmp(__v ? __np.truename() : __np.falsename());
+    string_type __nm = _VSTD::move(__tmp);
+#else
+    string_type __nm = __v ? __np.truename() : __np.falsename();
+#endif
+    for (typename string_type::iterator __i = __nm.begin(); __i != __nm.end(); ++__i, ++__s)
+        *__s = *__i;
+    return __s;
+}
+
+template <class _CharT, class _OutputIterator>
+_OutputIterator
+num_put<_CharT, _OutputIterator>::do_put(iter_type __s, ios_base& __iob,
+                                         char_type __fl, long __v) const
+{
+    // Stage 1 - Get number in narrow char
+    char __fmt[6] = {'%', 0};
+    const char* __len = "l";
+    this->__format_int(__fmt+1, __len, true, __iob.flags());
+    // Worst case is octal, with showbase enabled. Note that octal is always
+    // printed as an unsigned value.
+    _LIBCPP_CONSTEXPR const unsigned __nbuf
+        = (numeric_limits<unsigned long>::digits / 3)        // 1 char per 3 bits
+        + ((numeric_limits<unsigned long>::digits % 3) != 0) // round up
+        + 2; // base prefix + terminating null character                                                 // terminating null character
+    char __nar[__nbuf];
+    int __nc = __libcpp_snprintf_l(__nar, sizeof(__nar), _LIBCPP_GET_C_LOCALE, __fmt, __v);
+    char* __ne = __nar + __nc;
+    char* __np = this->__identify_padding(__nar, __ne, __iob);
+    // Stage 2 - Widen __nar while adding thousands separators
+    char_type __o[2*(__nbuf-1) - 1];
+    char_type* __op;  // pad here
+    char_type* __oe;  // end of output
+    this->__widen_and_group_int(__nar, __np, __ne, __o, __op, __oe, __iob.getloc());
+    // [__o, __oe) contains thousands_sep'd wide number
+    // Stage 3 & 4
+    return __pad_and_output(__s, __o, __op, __oe, __iob, __fl);
+}
+
+template <class _CharT, class _OutputIterator>
+_OutputIterator
+num_put<_CharT, _OutputIterator>::do_put(iter_type __s, ios_base& __iob,
+                                         char_type __fl, long long __v) const
+{
+    // Stage 1 - Get number in narrow char
+    char __fmt[8] = {'%', 0};
+    const char* __len = "ll";
+    this->__format_int(__fmt+1, __len, true, __iob.flags());
+    // Worst case is octal, with showbase enabled. Note that octal is always
+    // printed as an unsigned value.
+    _LIBCPP_CONSTEXPR const unsigned __nbuf
+        = (numeric_limits<unsigned long long>::digits / 3)        // 1 char per 3 bits
+        + ((numeric_limits<unsigned long long>::digits % 3) != 0) // round up
+        + 2; // base prefix + terminating null character                                                     // terminating null character
+    char __nar[__nbuf];
+    int __nc = __libcpp_snprintf_l(__nar, sizeof(__nar), _LIBCPP_GET_C_LOCALE, __fmt, __v);
+    char* __ne = __nar + __nc;
+    char* __np = this->__identify_padding(__nar, __ne, __iob);
+    // Stage 2 - Widen __nar while adding thousands separators
+    char_type __o[2*(__nbuf-1) - 1];
+    char_type* __op;  // pad here
+    char_type* __oe;  // end of output
+    this->__widen_and_group_int(__nar, __np, __ne, __o, __op, __oe, __iob.getloc());
+    // [__o, __oe) contains thousands_sep'd wide number
+    // Stage 3 & 4
+    return __pad_and_output(__s, __o, __op, __oe, __iob, __fl);
+}
+
+template <class _CharT, class _OutputIterator>
+_OutputIterator
+num_put<_CharT, _OutputIterator>::do_put(iter_type __s, ios_base& __iob,
+                                         char_type __fl, unsigned long __v) const
+{
+    // Stage 1 - Get number in narrow char
+    char __fmt[6] = {'%', 0};
+    const char* __len = "l";
+    this->__format_int(__fmt+1, __len, false, __iob.flags());
+    // Worst case is octal, with showbase enabled.
+    _LIBCPP_CONSTEXPR const unsigned __nbuf
+        = (numeric_limits<unsigned long>::digits / 3)        // 1 char per 3 bits
+        + ((numeric_limits<unsigned long>::digits % 3) != 0) // round up
+        + 2; // base prefix + terminating null character
+    char __nar[__nbuf];
+    int __nc = __libcpp_snprintf_l(__nar, sizeof(__nar), _LIBCPP_GET_C_LOCALE, __fmt, __v);
+    char* __ne = __nar + __nc;
+    char* __np = this->__identify_padding(__nar, __ne, __iob);
+    // Stage 2 - Widen __nar while adding thousands separators
+    char_type __o[2*(__nbuf-1) - 1];
+    char_type* __op;  // pad here
+    char_type* __oe;  // end of output
+    this->__widen_and_group_int(__nar, __np, __ne, __o, __op, __oe, __iob.getloc());
+    // [__o, __oe) contains thousands_sep'd wide number
+    // Stage 3 & 4
+    return __pad_and_output(__s, __o, __op, __oe, __iob, __fl);
+}
+
+template <class _CharT, class _OutputIterator>
+_OutputIterator
+num_put<_CharT, _OutputIterator>::do_put(iter_type __s, ios_base& __iob,
+                                         char_type __fl, unsigned long long __v) const
+{
+    // Stage 1 - Get number in narrow char
+    char __fmt[8] = {'%', 0};
+    const char* __len = "ll";
+    this->__format_int(__fmt+1, __len, false, __iob.flags());
+    // Worst case is octal, with showbase enabled.
+    _LIBCPP_CONSTEXPR const unsigned __nbuf
+        = (numeric_limits<unsigned long long>::digits / 3)        // 1 char per 3 bits
+        + ((numeric_limits<unsigned long long>::digits % 3) != 0) // round up
+        + 2; // base prefix + terminating null character
+    char __nar[__nbuf];
+    int __nc = __libcpp_snprintf_l(__nar, sizeof(__nar), _LIBCPP_GET_C_LOCALE, __fmt, __v);
+    char* __ne = __nar + __nc;
+    char* __np = this->__identify_padding(__nar, __ne, __iob);
+    // Stage 2 - Widen __nar while adding thousands separators
+    char_type __o[2*(__nbuf-1) - 1];
+    char_type* __op;  // pad here
+    char_type* __oe;  // end of output
+    this->__widen_and_group_int(__nar, __np, __ne, __o, __op, __oe, __iob.getloc());
+    // [__o, __oe) contains thousands_sep'd wide number
+    // Stage 3 & 4
+    return __pad_and_output(__s, __o, __op, __oe, __iob, __fl);
+}
+
+template <class _CharT, class _OutputIterator>
+_OutputIterator
+num_put<_CharT, _OutputIterator>::do_put(iter_type __s, ios_base& __iob,
+                                         char_type __fl, double __v) const
+{
+    // Stage 1 - Get number in narrow char
+    char __fmt[8] = {'%', 0};
+    const char* __len = "";
+    bool __specify_precision = this->__format_float(__fmt+1, __len, __iob.flags());
+    const unsigned __nbuf = 30;
+    char __nar[__nbuf];
+    char* __nb = __nar;
+    int __nc;
+    if (__specify_precision)
+        __nc = __libcpp_snprintf_l(__nb, __nbuf, _LIBCPP_GET_C_LOCALE, __fmt,
+                                   (int)__iob.precision(), __v);
+    else
+        __nc = __libcpp_snprintf_l(__nb, __nbuf, _LIBCPP_GET_C_LOCALE, __fmt, __v);
+    unique_ptr<char, void(*)(void*)> __nbh(nullptr, free);
+    if (__nc > static_cast<int>(__nbuf-1))
+    {
+        if (__specify_precision)
+            __nc = __libcpp_asprintf_l(&__nb, _LIBCPP_GET_C_LOCALE, __fmt, (int)__iob.precision(), __v);
+        else
+            __nc = __libcpp_asprintf_l(&__nb, _LIBCPP_GET_C_LOCALE, __fmt, __v);
+        if (__nc == -1)
+            __throw_bad_alloc();
+        __nbh.reset(__nb);
+    }
+    char* __ne = __nb + __nc;
+    char* __np = this->__identify_padding(__nb, __ne, __iob);
+    // Stage 2 - Widen __nar while adding thousands separators
+    char_type __o[2*(__nbuf-1) - 1];
+    char_type* __ob = __o;
+    unique_ptr<char_type, void(*)(void*)> __obh(0, free);
+    if (__nb != __nar)
+    {
+        __ob = (char_type*)malloc(2*static_cast<size_t>(__nc)*sizeof(char_type));
+        if (__ob == 0)
+            __throw_bad_alloc();
+        __obh.reset(__ob);
+    }
+    char_type* __op;  // pad here
+    char_type* __oe;  // end of output
+    this->__widen_and_group_float(__nb, __np, __ne, __ob, __op, __oe, __iob.getloc());
+    // [__o, __oe) contains thousands_sep'd wide number
+    // Stage 3 & 4
+    __s = __pad_and_output(__s, __ob, __op, __oe, __iob, __fl);
+    return __s;
+}
+
+template <class _CharT, class _OutputIterator>
+_OutputIterator
+num_put<_CharT, _OutputIterator>::do_put(iter_type __s, ios_base& __iob,
+                                         char_type __fl, long double __v) const
+{
+    // Stage 1 - Get number in narrow char
+    char __fmt[8] = {'%', 0};
+    const char* __len = "L";
+    bool __specify_precision = this->__format_float(__fmt+1, __len, __iob.flags());
+    const unsigned __nbuf = 30;
+    char __nar[__nbuf];
+    char* __nb = __nar;
+    int __nc;
+    if (__specify_precision)
+        __nc = __libcpp_snprintf_l(__nb, __nbuf, _LIBCPP_GET_C_LOCALE, __fmt,
+                                   (int)__iob.precision(), __v);
+    else
+        __nc = __libcpp_snprintf_l(__nb, __nbuf, _LIBCPP_GET_C_LOCALE, __fmt, __v);
+    unique_ptr<char, void(*)(void*)> __nbh(nullptr, free);
+    if (__nc > static_cast<int>(__nbuf-1))
+    {
+        if (__specify_precision)
+            __nc = __libcpp_asprintf_l(&__nb, _LIBCPP_GET_C_LOCALE, __fmt, (int)__iob.precision(), __v);
+        else
+            __nc = __libcpp_asprintf_l(&__nb, _LIBCPP_GET_C_LOCALE, __fmt, __v);
+        if (__nc == -1)
+            __throw_bad_alloc();
+        __nbh.reset(__nb);
+    }
+    char* __ne = __nb + __nc;
+    char* __np = this->__identify_padding(__nb, __ne, __iob);
+    // Stage 2 - Widen __nar while adding thousands separators
+    char_type __o[2*(__nbuf-1) - 1];
+    char_type* __ob = __o;
+    unique_ptr<char_type, void(*)(void*)> __obh(0, free);
+    if (__nb != __nar)
+    {
+        __ob = (char_type*)malloc(2*static_cast<size_t>(__nc)*sizeof(char_type));
+        if (__ob == 0)
+            __throw_bad_alloc();
+        __obh.reset(__ob);
+    }
+    char_type* __op;  // pad here
+    char_type* __oe;  // end of output
+    this->__widen_and_group_float(__nb, __np, __ne, __ob, __op, __oe, __iob.getloc());
+    // [__o, __oe) contains thousands_sep'd wide number
+    // Stage 3 & 4
+    __s = __pad_and_output(__s, __ob, __op, __oe, __iob, __fl);
+    return __s;
+}
+
+template <class _CharT, class _OutputIterator>
+_OutputIterator
+num_put<_CharT, _OutputIterator>::do_put(iter_type __s, ios_base& __iob,
+                                         char_type __fl, const void* __v) const
+{
+    // Stage 1 - Get pointer in narrow char
+    char __fmt[6] = "%p";
+    const unsigned __nbuf = 20;
+    char __nar[__nbuf];
+    int __nc = __libcpp_snprintf_l(__nar, sizeof(__nar), _LIBCPP_GET_C_LOCALE, __fmt, __v);
+    char* __ne = __nar + __nc;
+    char* __np = this->__identify_padding(__nar, __ne, __iob);
+    // Stage 2 - Widen __nar
+    char_type __o[2*(__nbuf-1) - 1];
+    char_type* __op;  // pad here
+    char_type* __oe;  // end of output
+    const ctype<char_type>& __ct = use_facet<ctype<char_type> >(__iob.getloc());
+    __ct.widen(__nar, __ne, __o);
+    __oe = __o + (__ne - __nar);
+    if (__np == __ne)
+        __op = __oe;
+    else
+        __op = __o + (__np - __nar);
+    // [__o, __oe) contains wide number
+    // Stage 3 & 4
+    return __pad_and_output(__s, __o, __op, __oe, __iob, __fl);
+}
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS num_put<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS num_put<wchar_t>)
+#endif
+
+template <class _CharT, class _InputIterator>
+_LIBCPP_HIDDEN
+int
+__get_up_to_n_digits(_InputIterator& __b, _InputIterator __e,
+                     ios_base::iostate& __err, const ctype<_CharT>& __ct, int __n)
+{
+    // Precondition:  __n >= 1
+    if (__b == __e)
+    {
+        __err |= ios_base::eofbit | ios_base::failbit;
+        return 0;
+    }
+    // get first digit
+    _CharT __c = *__b;
+    if (!__ct.is(ctype_base::digit, __c))
+    {
+        __err |= ios_base::failbit;
+        return 0;
+    }
+    int __r = __ct.narrow(__c, 0) - '0';
+    for (++__b, (void) --__n; __b != __e && __n > 0; ++__b, (void) --__n)
+    {
+        // get next digit
+        __c = *__b;
+        if (!__ct.is(ctype_base::digit, __c))
+            return __r;
+        __r = __r * 10 + __ct.narrow(__c, 0) - '0';
+    }
+    if (__b == __e)
+        __err |= ios_base::eofbit;
+    return __r;
+}
+
+class _LIBCPP_TYPE_VIS time_base
+{
+public:
+    enum dateorder {no_order, dmy, mdy, ymd, ydm};
+};
+
+#ifdef _LIBCPP_COMPILER_MSVC
+// __time_get_c_storage should only be used for private inheritance to avoid
+// problems with non-virtual destructor
+#pragma warning ( push )
+#pragma warning ( disable : 4265 )
+#endif
+
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS __time_get_c_storage
+{
+protected:
+    typedef basic_string<_CharT> string_type;
+
+    virtual const string_type* __weeks() const;
+    virtual const string_type* __months() const;
+    virtual const string_type* __am_pm() const;
+    virtual const string_type& __c() const;
+    virtual const string_type& __r() const;
+    virtual const string_type& __x() const;
+    virtual const string_type& __X() const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~__time_get_c_storage() {}
+};
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+template <> _LIBCPP_FUNC_VIS const string* __time_get_c_storage<char>::__weeks() const;
+template <> _LIBCPP_FUNC_VIS const string* __time_get_c_storage<char>::__months() const;
+template <> _LIBCPP_FUNC_VIS const string* __time_get_c_storage<char>::__am_pm() const;
+template <> _LIBCPP_FUNC_VIS const string& __time_get_c_storage<char>::__c() const;
+template <> _LIBCPP_FUNC_VIS const string& __time_get_c_storage<char>::__r() const;
+template <> _LIBCPP_FUNC_VIS const string& __time_get_c_storage<char>::__x() const;
+template <> _LIBCPP_FUNC_VIS const string& __time_get_c_storage<char>::__X() const;
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <> _LIBCPP_FUNC_VIS const wstring* __time_get_c_storage<wchar_t>::__weeks() const;
+template <> _LIBCPP_FUNC_VIS const wstring* __time_get_c_storage<wchar_t>::__months() const;
+template <> _LIBCPP_FUNC_VIS const wstring* __time_get_c_storage<wchar_t>::__am_pm() const;
+template <> _LIBCPP_FUNC_VIS const wstring& __time_get_c_storage<wchar_t>::__c() const;
+template <> _LIBCPP_FUNC_VIS const wstring& __time_get_c_storage<wchar_t>::__r() const;
+template <> _LIBCPP_FUNC_VIS const wstring& __time_get_c_storage<wchar_t>::__x() const;
+template <> _LIBCPP_FUNC_VIS const wstring& __time_get_c_storage<wchar_t>::__X() const;
+#endif
+
+template <class _CharT, class _InputIterator = istreambuf_iterator<_CharT> >
+class _LIBCPP_TEMPLATE_VIS time_get
+    : public locale::facet,
+      public time_base,
+      private __time_get_c_storage<_CharT>
+{
+public:
+    typedef _CharT                  char_type;
+    typedef _InputIterator          iter_type;
+    typedef time_base::dateorder    dateorder;
+    typedef basic_string<char_type> string_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit time_get(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    dateorder date_order() const
+    {
+        return this->do_date_order();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get_time(iter_type __b, iter_type __e, ios_base& __iob,
+                       ios_base::iostate& __err, tm* __tm) const
+    {
+        return do_get_time(__b, __e, __iob, __err, __tm);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get_date(iter_type __b, iter_type __e, ios_base& __iob,
+                       ios_base::iostate& __err, tm* __tm) const
+    {
+        return do_get_date(__b, __e, __iob, __err, __tm);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get_weekday(iter_type __b, iter_type __e, ios_base& __iob,
+                          ios_base::iostate& __err, tm* __tm) const
+    {
+        return do_get_weekday(__b, __e, __iob, __err, __tm);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get_monthname(iter_type __b, iter_type __e, ios_base& __iob,
+                            ios_base::iostate& __err, tm* __tm) const
+    {
+        return do_get_monthname(__b, __e, __iob, __err, __tm);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get_year(iter_type __b, iter_type __e, ios_base& __iob,
+                       ios_base::iostate& __err, tm* __tm) const
+    {
+        return do_get_year(__b, __e, __iob, __err, __tm);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, ios_base& __iob,
+                  ios_base::iostate& __err, tm *__tm,
+                  char __fmt, char __mod = 0) const
+    {
+        return do_get(__b, __e, __iob, __err, __tm, __fmt, __mod);
+    }
+
+    iter_type get(iter_type __b, iter_type __e, ios_base& __iob,
+                  ios_base::iostate& __err, tm* __tm,
+                  const char_type* __fmtb, const char_type* __fmte) const;
+
+    static locale::id id;
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    ~time_get() {}
+
+    virtual dateorder do_date_order() const;
+    virtual iter_type do_get_time(iter_type __b, iter_type __e, ios_base& __iob,
+                                  ios_base::iostate& __err, tm* __tm) const;
+    virtual iter_type do_get_date(iter_type __b, iter_type __e, ios_base& __iob,
+                                  ios_base::iostate& __err, tm* __tm) const;
+    virtual iter_type do_get_weekday(iter_type __b, iter_type __e, ios_base& __iob,
+                                     ios_base::iostate& __err, tm* __tm) const;
+    virtual iter_type do_get_monthname(iter_type __b, iter_type __e, ios_base& __iob,
+                                       ios_base::iostate& __err, tm* __tm) const;
+    virtual iter_type do_get_year(iter_type __b, iter_type __e, ios_base& __iob,
+                                  ios_base::iostate& __err, tm* __tm) const;
+    virtual iter_type do_get(iter_type __b, iter_type __e, ios_base& __iob,
+                             ios_base::iostate& __err, tm* __tm,
+                             char __fmt, char __mod) const;
+private:
+    void __get_white_space(iter_type& __b, iter_type __e,
+                           ios_base::iostate& __err, const ctype<char_type>& __ct) const;
+    void __get_percent(iter_type& __b, iter_type __e, ios_base::iostate& __err,
+                       const ctype<char_type>& __ct) const;
+
+    void __get_weekdayname(int& __m,
+                           iter_type& __b, iter_type __e,
+                           ios_base::iostate& __err,
+                           const ctype<char_type>& __ct) const;
+    void __get_monthname(int& __m,
+                         iter_type& __b, iter_type __e,
+                         ios_base::iostate& __err,
+                         const ctype<char_type>& __ct) const;
+    void __get_day(int& __d,
+                   iter_type& __b, iter_type __e,
+                   ios_base::iostate& __err,
+                   const ctype<char_type>& __ct) const;
+    void __get_month(int& __m,
+                     iter_type& __b, iter_type __e,
+                     ios_base::iostate& __err,
+                     const ctype<char_type>& __ct) const;
+    void __get_year(int& __y,
+                   iter_type& __b, iter_type __e,
+                   ios_base::iostate& __err,
+                   const ctype<char_type>& __ct) const;
+    void __get_year4(int& __y,
+                    iter_type& __b, iter_type __e,
+                    ios_base::iostate& __err,
+                    const ctype<char_type>& __ct) const;
+    void __get_hour(int& __d,
+                    iter_type& __b, iter_type __e,
+                    ios_base::iostate& __err,
+                    const ctype<char_type>& __ct) const;
+    void __get_12_hour(int& __h,
+                       iter_type& __b, iter_type __e,
+                       ios_base::iostate& __err,
+                       const ctype<char_type>& __ct) const;
+    void __get_am_pm(int& __h,
+                     iter_type& __b, iter_type __e,
+                     ios_base::iostate& __err,
+                     const ctype<char_type>& __ct) const;
+    void __get_minute(int& __m,
+                      iter_type& __b, iter_type __e,
+                      ios_base::iostate& __err,
+                      const ctype<char_type>& __ct) const;
+    void __get_second(int& __s,
+                      iter_type& __b, iter_type __e,
+                      ios_base::iostate& __err,
+                      const ctype<char_type>& __ct) const;
+    void __get_weekday(int& __w,
+                       iter_type& __b, iter_type __e,
+                       ios_base::iostate& __err,
+                       const ctype<char_type>& __ct) const;
+    void __get_day_year_num(int& __w,
+                            iter_type& __b, iter_type __e,
+                            ios_base::iostate& __err,
+                            const ctype<char_type>& __ct) const;
+};
+
+template <class _CharT, class _InputIterator>
+locale::id
+time_get<_CharT, _InputIterator>::id;
+
+// time_get primitives
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_weekdayname(int& __w,
+                                                    iter_type& __b, iter_type __e,
+                                                    ios_base::iostate& __err,
+                                                    const ctype<char_type>& __ct) const
+{
+    // Note:  ignoring case comes from the POSIX strptime spec
+    const string_type* __wk = this->__weeks();
+    ptrdiff_t __i = _VSTD::__scan_keyword(__b, __e, __wk, __wk+14, __ct, __err, false) - __wk;
+    if (__i < 14)
+        __w = __i % 7;
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_monthname(int& __m,
+                                                  iter_type& __b, iter_type __e,
+                                                  ios_base::iostate& __err,
+                                                  const ctype<char_type>& __ct) const
+{
+    // Note:  ignoring case comes from the POSIX strptime spec
+    const string_type* __month = this->__months();
+    ptrdiff_t __i = _VSTD::__scan_keyword(__b, __e, __month, __month+24, __ct, __err, false) - __month;
+    if (__i < 24)
+        __m = __i % 12;
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_day(int& __d,
+                                            iter_type& __b, iter_type __e,
+                                            ios_base::iostate& __err,
+                                            const ctype<char_type>& __ct) const
+{
+    int __t = _VSTD::__get_up_to_n_digits(__b, __e, __err, __ct, 2);
+    if (!(__err & ios_base::failbit) && 1 <= __t && __t <= 31)
+        __d = __t;
+    else
+        __err |= ios_base::failbit;
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_month(int& __m,
+                                              iter_type& __b, iter_type __e,
+                                              ios_base::iostate& __err,
+                                              const ctype<char_type>& __ct) const
+{
+    int __t = __get_up_to_n_digits(__b, __e, __err, __ct, 2) - 1;
+    if (!(__err & ios_base::failbit) && __t <= 11)
+        __m = __t;
+    else
+        __err |= ios_base::failbit;
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_year(int& __y,
+                                             iter_type& __b, iter_type __e,
+                                             ios_base::iostate& __err,
+                                             const ctype<char_type>& __ct) const
+{
+    int __t = __get_up_to_n_digits(__b, __e, __err, __ct, 4);
+    if (!(__err & ios_base::failbit))
+    {
+        if (__t < 69)
+            __t += 2000;
+        else if (69 <= __t && __t <= 99)
+            __t += 1900;
+        __y = __t - 1900;
+    }
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_year4(int& __y,
+                                              iter_type& __b, iter_type __e,
+                                              ios_base::iostate& __err,
+                                              const ctype<char_type>& __ct) const
+{
+    int __t = __get_up_to_n_digits(__b, __e, __err, __ct, 4);
+    if (!(__err & ios_base::failbit))
+        __y = __t - 1900;
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_hour(int& __h,
+                                             iter_type& __b, iter_type __e,
+                                             ios_base::iostate& __err,
+                                             const ctype<char_type>& __ct) const
+{
+    int __t = __get_up_to_n_digits(__b, __e, __err, __ct, 2);
+    if (!(__err & ios_base::failbit) && __t <= 23)
+        __h = __t;
+    else
+        __err |= ios_base::failbit;
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_12_hour(int& __h,
+                                                iter_type& __b, iter_type __e,
+                                                ios_base::iostate& __err,
+                                                const ctype<char_type>& __ct) const
+{
+    int __t = __get_up_to_n_digits(__b, __e, __err, __ct, 2);
+    if (!(__err & ios_base::failbit) && 1 <= __t && __t <= 12)
+        __h = __t;
+    else
+        __err |= ios_base::failbit;
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_minute(int& __m,
+                                               iter_type& __b, iter_type __e,
+                                               ios_base::iostate& __err,
+                                               const ctype<char_type>& __ct) const
+{
+    int __t = __get_up_to_n_digits(__b, __e, __err, __ct, 2);
+    if (!(__err & ios_base::failbit) && __t <= 59)
+        __m = __t;
+    else
+        __err |= ios_base::failbit;
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_second(int& __s,
+                                               iter_type& __b, iter_type __e,
+                                               ios_base::iostate& __err,
+                                               const ctype<char_type>& __ct) const
+{
+    int __t = __get_up_to_n_digits(__b, __e, __err, __ct, 2);
+    if (!(__err & ios_base::failbit) && __t <= 60)
+        __s = __t;
+    else
+        __err |= ios_base::failbit;
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_weekday(int& __w,
+                                                iter_type& __b, iter_type __e,
+                                                ios_base::iostate& __err,
+                                                const ctype<char_type>& __ct) const
+{
+    int __t = __get_up_to_n_digits(__b, __e, __err, __ct, 1);
+    if (!(__err & ios_base::failbit) && __t <= 6)
+        __w = __t;
+    else
+        __err |= ios_base::failbit;
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_day_year_num(int& __d,
+                                                     iter_type& __b, iter_type __e,
+                                                     ios_base::iostate& __err,
+                                                     const ctype<char_type>& __ct) const
+{
+    int __t = __get_up_to_n_digits(__b, __e, __err, __ct, 3);
+    if (!(__err & ios_base::failbit) && __t <= 365)
+        __d = __t;
+    else
+        __err |= ios_base::failbit;
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_white_space(iter_type& __b, iter_type __e,
+                                                    ios_base::iostate& __err,
+                                                    const ctype<char_type>& __ct) const
+{
+    for (; __b != __e && __ct.is(ctype_base::space, *__b); ++__b)
+        ;
+    if (__b == __e)
+        __err |= ios_base::eofbit;
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_am_pm(int& __h,
+                                              iter_type& __b, iter_type __e,
+                                              ios_base::iostate& __err,
+                                              const ctype<char_type>& __ct) const
+{
+    const string_type* __ap = this->__am_pm();
+    if (__ap[0].size() + __ap[1].size() == 0)
+    {
+        __err |= ios_base::failbit;
+        return;
+    }
+    ptrdiff_t __i = _VSTD::__scan_keyword(__b, __e, __ap, __ap+2, __ct, __err, false) - __ap;
+    if (__i == 0 && __h == 12)
+        __h = 0;
+    else if (__i == 1 && __h < 12)
+        __h += 12;
+}
+
+template <class _CharT, class _InputIterator>
+void
+time_get<_CharT, _InputIterator>::__get_percent(iter_type& __b, iter_type __e,
+                                                ios_base::iostate& __err,
+                                                const ctype<char_type>& __ct) const
+{
+    if (__b == __e)
+    {
+        __err |= ios_base::eofbit | ios_base::failbit;
+        return;
+    }
+    if (__ct.narrow(*__b, 0) != '%')
+        __err |= ios_base::failbit;
+    else if(++__b == __e)
+        __err |= ios_base::eofbit;
+}
+
+// time_get end primitives
+
+template <class _CharT, class _InputIterator>
+_InputIterator
+time_get<_CharT, _InputIterator>::get(iter_type __b, iter_type __e,
+                                      ios_base& __iob,
+                                      ios_base::iostate& __err, tm* __tm,
+                                      const char_type* __fmtb, const char_type* __fmte) const
+{
+    const ctype<char_type>& __ct = use_facet<ctype<char_type> >(__iob.getloc());
+    __err = ios_base::goodbit;
+    while (__fmtb != __fmte && __err == ios_base::goodbit)
+    {
+        if (__b == __e)
+        {
+            __err = ios_base::failbit;
+            break;
+        }
+        if (__ct.narrow(*__fmtb, 0) == '%')
+        {
+            if (++__fmtb == __fmte)
+            {
+                __err = ios_base::failbit;
+                break;
+            }
+            char __cmd = __ct.narrow(*__fmtb, 0);
+            char __opt = '\0';
+            if (__cmd == 'E' || __cmd == '0')
+            {
+                if (++__fmtb == __fmte)
+                {
+                    __err = ios_base::failbit;
+                    break;
+                }
+                __opt = __cmd;
+                __cmd = __ct.narrow(*__fmtb, 0);
+            }
+            __b = do_get(__b, __e, __iob, __err, __tm, __cmd, __opt);
+            ++__fmtb;
+        }
+        else if (__ct.is(ctype_base::space, *__fmtb))
+        {
+            for (++__fmtb; __fmtb != __fmte && __ct.is(ctype_base::space, *__fmtb); ++__fmtb)
+                ;
+            for (        ;    __b != __e    && __ct.is(ctype_base::space, *__b);    ++__b)
+                ;
+        }
+        else if (__ct.toupper(*__b) == __ct.toupper(*__fmtb))
+        {
+            ++__b;
+            ++__fmtb;
+        }
+        else
+            __err = ios_base::failbit;
+    }
+    if (__b == __e)
+        __err |= ios_base::eofbit;
+    return __b;
+}
+
+template <class _CharT, class _InputIterator>
+typename time_get<_CharT, _InputIterator>::dateorder
+time_get<_CharT, _InputIterator>::do_date_order() const
+{
+    return mdy;
+}
+
+template <class _CharT, class _InputIterator>
+_InputIterator
+time_get<_CharT, _InputIterator>::do_get_time(iter_type __b, iter_type __e,
+                                              ios_base& __iob,
+                                              ios_base::iostate& __err,
+                                              tm* __tm) const
+{
+    const char_type __fmt[] = {'%', 'H', ':', '%', 'M', ':', '%', 'S'};
+    return get(__b, __e, __iob, __err, __tm, __fmt, __fmt + sizeof(__fmt)/sizeof(__fmt[0]));
+}
+
+template <class _CharT, class _InputIterator>
+_InputIterator
+time_get<_CharT, _InputIterator>::do_get_date(iter_type __b, iter_type __e,
+                                              ios_base& __iob,
+                                              ios_base::iostate& __err,
+                                              tm* __tm) const
+{
+    const string_type& __fmt = this->__x();
+    return get(__b, __e, __iob, __err, __tm, __fmt.data(), __fmt.data() + __fmt.size());
+}
+
+template <class _CharT, class _InputIterator>
+_InputIterator
+time_get<_CharT, _InputIterator>::do_get_weekday(iter_type __b, iter_type __e,
+                                                 ios_base& __iob,
+                                                 ios_base::iostate& __err,
+                                                 tm* __tm) const
+{
+    const ctype<char_type>& __ct = use_facet<ctype<char_type> >(__iob.getloc());
+    __get_weekdayname(__tm->tm_wday, __b, __e, __err, __ct);
+    return __b;
+}
+
+template <class _CharT, class _InputIterator>
+_InputIterator
+time_get<_CharT, _InputIterator>::do_get_monthname(iter_type __b, iter_type __e,
+                                                   ios_base& __iob,
+                                                   ios_base::iostate& __err,
+                                                   tm* __tm) const
+{
+    const ctype<char_type>& __ct = use_facet<ctype<char_type> >(__iob.getloc());
+    __get_monthname(__tm->tm_mon, __b, __e, __err, __ct);
+    return __b;
+}
+
+template <class _CharT, class _InputIterator>
+_InputIterator
+time_get<_CharT, _InputIterator>::do_get_year(iter_type __b, iter_type __e,
+                                              ios_base& __iob,
+                                              ios_base::iostate& __err,
+                                              tm* __tm) const
+{
+    const ctype<char_type>& __ct = use_facet<ctype<char_type> >(__iob.getloc());
+    __get_year(__tm->tm_year, __b, __e, __err, __ct);
+    return __b;
+}
+
+template <class _CharT, class _InputIterator>
+_InputIterator
+time_get<_CharT, _InputIterator>::do_get(iter_type __b, iter_type __e,
+                                         ios_base& __iob,
+                                         ios_base::iostate& __err, tm* __tm,
+                                         char __fmt, char) const
+{
+    __err = ios_base::goodbit;
+    const ctype<char_type>& __ct = use_facet<ctype<char_type> >(__iob.getloc());
+    switch (__fmt)
+    {
+    case 'a':
+    case 'A':
+        __get_weekdayname(__tm->tm_wday, __b, __e, __err, __ct);
+        break;
+    case 'b':
+    case 'B':
+    case 'h':
+        __get_monthname(__tm->tm_mon, __b, __e, __err, __ct);
+        break;
+    case 'c':
+        {
+        const string_type& __fm = this->__c();
+        __b = get(__b, __e, __iob, __err, __tm, __fm.data(), __fm.data() + __fm.size());
+        }
+        break;
+    case 'd':
+    case 'e':
+        __get_day(__tm->tm_mday, __b, __e, __err, __ct);
+        break;
+    case 'D':
+        {
+        const char_type __fm[] = {'%', 'm', '/', '%', 'd', '/', '%', 'y'};
+        __b = get(__b, __e, __iob, __err, __tm, __fm, __fm + sizeof(__fm)/sizeof(__fm[0]));
+        }
+        break;
+    case 'F':
+        {
+        const char_type __fm[] = {'%', 'Y', '-', '%', 'm', '-', '%', 'd'};
+        __b = get(__b, __e, __iob, __err, __tm, __fm, __fm + sizeof(__fm)/sizeof(__fm[0]));
+        }
+        break;
+    case 'H':
+        __get_hour(__tm->tm_hour, __b, __e, __err, __ct);
+        break;
+    case 'I':
+        __get_12_hour(__tm->tm_hour, __b, __e, __err, __ct);
+        break;
+    case 'j':
+        __get_day_year_num(__tm->tm_yday, __b, __e, __err, __ct);
+        break;
+    case 'm':
+        __get_month(__tm->tm_mon, __b, __e, __err, __ct);
+        break;
+    case 'M':
+        __get_minute(__tm->tm_min, __b, __e, __err, __ct);
+        break;
+    case 'n':
+    case 't':
+        __get_white_space(__b, __e, __err, __ct);
+        break;
+    case 'p':
+        __get_am_pm(__tm->tm_hour, __b, __e, __err, __ct);
+        break;
+    case 'r':
+        {
+        const char_type __fm[] = {'%', 'I', ':', '%', 'M', ':', '%', 'S', ' ', '%', 'p'};
+        __b = get(__b, __e, __iob, __err, __tm, __fm, __fm + sizeof(__fm)/sizeof(__fm[0]));
+        }
+        break;
+    case 'R':
+        {
+        const char_type __fm[] = {'%', 'H', ':', '%', 'M'};
+        __b = get(__b, __e, __iob, __err, __tm, __fm, __fm + sizeof(__fm)/sizeof(__fm[0]));
+        }
+        break;
+    case 'S':
+        __get_second(__tm->tm_sec, __b, __e, __err, __ct);
+        break;
+    case 'T':
+        {
+        const char_type __fm[] = {'%', 'H', ':', '%', 'M', ':', '%', 'S'};
+        __b = get(__b, __e, __iob, __err, __tm, __fm, __fm + sizeof(__fm)/sizeof(__fm[0]));
+        }
+        break;
+    case 'w':
+        __get_weekday(__tm->tm_wday, __b, __e, __err, __ct);
+        break;
+    case 'x':
+        return do_get_date(__b, __e, __iob, __err, __tm);
+    case 'X':
+        {
+        const string_type& __fm = this->__X();
+        __b = get(__b, __e, __iob, __err, __tm, __fm.data(), __fm.data() + __fm.size());
+        }
+        break;
+    case 'y':
+        __get_year(__tm->tm_year, __b, __e, __err, __ct);
+        break;
+    case 'Y':
+        __get_year4(__tm->tm_year, __b, __e, __err, __ct);
+        break;
+    case '%':
+        __get_percent(__b, __e, __err, __ct);
+        break;
+    default:
+        __err |= ios_base::failbit;
+    }
+    return __b;
+}
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS time_get<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS time_get<wchar_t>)
+#endif
+
+class _LIBCPP_TYPE_VIS __time_get
+{
+protected:
+    locale_t __loc_;
+
+    __time_get(const char* __nm);
+    __time_get(const string& __nm);
+    ~__time_get();
+};
+
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS __time_get_storage
+    : public __time_get
+{
+protected:
+    typedef basic_string<_CharT> string_type;
+
+    string_type __weeks_[14];
+    string_type __months_[24];
+    string_type __am_pm_[2];
+    string_type __c_;
+    string_type __r_;
+    string_type __x_;
+    string_type __X_;
+
+    explicit __time_get_storage(const char* __nm);
+    explicit __time_get_storage(const string& __nm);
+
+    _LIBCPP_INLINE_VISIBILITY ~__time_get_storage() {}
+
+    time_base::dateorder __do_date_order() const;
+
+private:
+    void init(const ctype<_CharT>&);
+    string_type __analyze(char __fmt, const ctype<_CharT>&);
+};
+
+#define _LIBCPP_TIME_GET_STORAGE_EXPLICIT_INSTANTIATION(_CharT) \
+template <> _LIBCPP_FUNC_VIS time_base::dateorder __time_get_storage<_CharT>::__do_date_order() const; \
+template <> _LIBCPP_FUNC_VIS __time_get_storage<_CharT>::__time_get_storage(const char*); \
+template <> _LIBCPP_FUNC_VIS __time_get_storage<_CharT>::__time_get_storage(const string&); \
+template <> _LIBCPP_FUNC_VIS void __time_get_storage<_CharT>::init(const ctype<_CharT>&); \
+template <> _LIBCPP_FUNC_VIS __time_get_storage<_CharT>::string_type __time_get_storage<_CharT>::__analyze(char, const ctype<_CharT>&); \
+extern template _LIBCPP_FUNC_VIS time_base::dateorder __time_get_storage<_CharT>::__do_date_order() const; \
+extern template _LIBCPP_FUNC_VIS __time_get_storage<_CharT>::__time_get_storage(const char*); \
+extern template _LIBCPP_FUNC_VIS __time_get_storage<_CharT>::__time_get_storage(const string&); \
+extern template _LIBCPP_FUNC_VIS void __time_get_storage<_CharT>::init(const ctype<_CharT>&); \
+extern template _LIBCPP_FUNC_VIS __time_get_storage<_CharT>::string_type __time_get_storage<_CharT>::__analyze(char, const ctype<_CharT>&); \
+/**/
+
+_LIBCPP_TIME_GET_STORAGE_EXPLICIT_INSTANTIATION(char)
+_LIBCPP_TIME_GET_STORAGE_EXPLICIT_INSTANTIATION(wchar_t)
+#undef _LIBCPP_TIME_GET_STORAGE_EXPLICIT_INSTANTIATION
+
+template <class _CharT, class _InputIterator = istreambuf_iterator<_CharT> >
+class _LIBCPP_TEMPLATE_VIS time_get_byname
+    : public time_get<_CharT, _InputIterator>,
+      private __time_get_storage<_CharT>
+{
+public:
+    typedef time_base::dateorder    dateorder;
+    typedef _InputIterator          iter_type;
+    typedef _CharT                  char_type;
+    typedef basic_string<char_type> string_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit time_get_byname(const char* __nm, size_t __refs = 0)
+        : time_get<_CharT, _InputIterator>(__refs),
+          __time_get_storage<_CharT>(__nm) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit time_get_byname(const string& __nm, size_t __refs = 0)
+        : time_get<_CharT, _InputIterator>(__refs),
+          __time_get_storage<_CharT>(__nm) {}
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    ~time_get_byname() {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    virtual dateorder do_date_order() const {return this->__do_date_order();}
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    virtual const string_type* __weeks() const  {return this->__weeks_;}
+    _LIBCPP_INLINE_VISIBILITY
+    virtual const string_type* __months() const {return this->__months_;}
+    _LIBCPP_INLINE_VISIBILITY
+    virtual const string_type* __am_pm() const  {return this->__am_pm_;}
+    _LIBCPP_INLINE_VISIBILITY
+    virtual const string_type& __c() const      {return this->__c_;}
+    _LIBCPP_INLINE_VISIBILITY
+    virtual const string_type& __r() const      {return this->__r_;}
+    _LIBCPP_INLINE_VISIBILITY
+    virtual const string_type& __x() const      {return this->__x_;}
+    _LIBCPP_INLINE_VISIBILITY
+    virtual const string_type& __X() const      {return this->__X_;}
+};
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS time_get_byname<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS time_get_byname<wchar_t>)
+#endif
+
+class _LIBCPP_TYPE_VIS __time_put
+{
+    locale_t __loc_;
+protected:
+    _LIBCPP_INLINE_VISIBILITY __time_put() : __loc_(_LIBCPP_GET_C_LOCALE) {}
+    __time_put(const char* __nm);
+    __time_put(const string& __nm);
+    ~__time_put();
+    void __do_put(char* __nb, char*& __ne, const tm* __tm,
+                  char __fmt, char __mod) const;
+    void __do_put(wchar_t* __wb, wchar_t*& __we, const tm* __tm,
+                  char __fmt, char __mod) const;
+};
+
+template <class _CharT, class _OutputIterator = ostreambuf_iterator<_CharT> >
+class _LIBCPP_TEMPLATE_VIS time_put
+    : public locale::facet,
+      private __time_put
+{
+public:
+    typedef _CharT char_type;
+    typedef _OutputIterator iter_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit time_put(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    iter_type put(iter_type __s, ios_base& __iob, char_type __fl, const tm* __tm,
+                  const char_type* __pb, const char_type* __pe) const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type put(iter_type __s, ios_base& __iob, char_type __fl,
+                  const tm* __tm, char __fmt, char __mod = 0) const
+    {
+        return do_put(__s, __iob, __fl, __tm, __fmt, __mod);
+    }
+
+    static locale::id id;
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    ~time_put() {}
+    virtual iter_type do_put(iter_type __s, ios_base&, char_type, const tm* __tm,
+                             char __fmt, char __mod) const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit time_put(const char* __nm, size_t __refs)
+        : locale::facet(__refs),
+          __time_put(__nm) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit time_put(const string& __nm, size_t __refs)
+        : locale::facet(__refs),
+          __time_put(__nm) {}
+};
+
+template <class _CharT, class _OutputIterator>
+locale::id
+time_put<_CharT, _OutputIterator>::id;
+
+template <class _CharT, class _OutputIterator>
+_OutputIterator
+time_put<_CharT, _OutputIterator>::put(iter_type __s, ios_base& __iob,
+                                       char_type __fl, const tm* __tm,
+                                       const char_type* __pb,
+                                       const char_type* __pe) const
+{
+    const ctype<char_type>& __ct = use_facet<ctype<char_type> >(__iob.getloc());
+    for (; __pb != __pe; ++__pb)
+    {
+        if (__ct.narrow(*__pb, 0) == '%')
+        {
+            if (++__pb == __pe)
+            {
+                *__s++ = __pb[-1];
+                break;
+            }
+            char __mod = 0;
+            char __fmt = __ct.narrow(*__pb, 0);
+            if (__fmt == 'E' || __fmt == 'O')
+            {
+                if (++__pb == __pe)
+                {
+                    *__s++ = __pb[-2];
+                    *__s++ = __pb[-1];
+                    break;
+                }
+                __mod = __fmt;
+                __fmt = __ct.narrow(*__pb, 0);
+            }
+            __s = do_put(__s, __iob, __fl, __tm, __fmt, __mod);
+        }
+        else
+            *__s++ = *__pb;
+    }
+    return __s;
+}
+
+template <class _CharT, class _OutputIterator>
+_OutputIterator
+time_put<_CharT, _OutputIterator>::do_put(iter_type __s, ios_base&,
+                                          char_type, const tm* __tm,
+                                          char __fmt, char __mod) const
+{
+    char_type __nar[100];
+    char_type* __nb = __nar;
+    char_type* __ne = __nb + 100;
+    __do_put(__nb, __ne, __tm, __fmt, __mod);
+    return _VSTD::copy(__nb, __ne, __s);
+}
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS time_put<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS time_put<wchar_t>)
+#endif
+
+template <class _CharT, class _OutputIterator = ostreambuf_iterator<_CharT> >
+class _LIBCPP_TEMPLATE_VIS time_put_byname
+    : public time_put<_CharT, _OutputIterator>
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit time_put_byname(const char* __nm, size_t __refs = 0)
+        : time_put<_CharT, _OutputIterator>(__nm, __refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit time_put_byname(const string& __nm, size_t __refs = 0)
+        : time_put<_CharT, _OutputIterator>(__nm, __refs) {}
+
+protected:
+#if defined(_MSC_VER) && defined(__clang__)
+    ~time_put_byname() {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    ~time_put_byname() {}
+#endif
+};
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS time_put_byname<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS time_put_byname<wchar_t>)
+#endif
+
+// money_base
+
+class _LIBCPP_TYPE_VIS money_base
+{
+public:
+    enum part {none, space, symbol, sign, value};
+    struct pattern {char field[4];};
+
+    _LIBCPP_INLINE_VISIBILITY money_base() {}
+};
+
+// moneypunct
+
+template <class _CharT, bool _International = false>
+class _LIBCPP_TEMPLATE_VIS moneypunct
+    : public locale::facet,
+      public money_base
+{
+public:
+    typedef _CharT                  char_type;
+    typedef basic_string<char_type> string_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit moneypunct(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY char_type   decimal_point() const {return do_decimal_point();}
+    _LIBCPP_INLINE_VISIBILITY char_type   thousands_sep() const {return do_thousands_sep();}
+    _LIBCPP_INLINE_VISIBILITY string      grouping()      const {return do_grouping();}
+    _LIBCPP_INLINE_VISIBILITY string_type curr_symbol()   const {return do_curr_symbol();}
+    _LIBCPP_INLINE_VISIBILITY string_type positive_sign() const {return do_positive_sign();}
+    _LIBCPP_INLINE_VISIBILITY string_type negative_sign() const {return do_negative_sign();}
+    _LIBCPP_INLINE_VISIBILITY int         frac_digits()   const {return do_frac_digits();}
+    _LIBCPP_INLINE_VISIBILITY pattern     pos_format()    const {return do_pos_format();}
+    _LIBCPP_INLINE_VISIBILITY pattern     neg_format()    const {return do_neg_format();}
+
+    static locale::id id;
+    static const bool intl = _International;
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    ~moneypunct() {}
+
+    virtual char_type   do_decimal_point() const {return numeric_limits<char_type>::max();}
+    virtual char_type   do_thousands_sep() const {return numeric_limits<char_type>::max();}
+    virtual string      do_grouping()      const {return string();}
+    virtual string_type do_curr_symbol()   const {return string_type();}
+    virtual string_type do_positive_sign() const {return string_type();}
+    virtual string_type do_negative_sign() const {return string_type(1, '-');}
+    virtual int         do_frac_digits()   const {return 0;}
+    virtual pattern     do_pos_format()    const
+        {pattern __p = {{symbol, sign, none, value}}; return __p;}
+    virtual pattern     do_neg_format()    const
+        {pattern __p = {{symbol, sign, none, value}}; return __p;}
+};
+
+template <class _CharT, bool _International>
+locale::id
+moneypunct<_CharT, _International>::id;
+
+template <class _CharT, bool _International>
+const bool
+moneypunct<_CharT, _International>::intl;
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS moneypunct<char, false>)
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS moneypunct<char, true>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS moneypunct<wchar_t, false>)
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS moneypunct<wchar_t, true>)
+#endif
+
+// moneypunct_byname
+
+template <class _CharT, bool _International = false>
+class _LIBCPP_TEMPLATE_VIS moneypunct_byname
+    : public moneypunct<_CharT, _International>
+{
+public:
+    typedef money_base::pattern  pattern;
+    typedef _CharT                  char_type;
+    typedef basic_string<char_type> string_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit moneypunct_byname(const char* __nm, size_t __refs = 0)
+        : moneypunct<_CharT, _International>(__refs) {init(__nm);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit moneypunct_byname(const string& __nm, size_t __refs = 0)
+        : moneypunct<_CharT, _International>(__refs) {init(__nm.c_str());}
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    ~moneypunct_byname() {}
+
+    virtual char_type   do_decimal_point() const {return __decimal_point_;}
+    virtual char_type   do_thousands_sep() const {return __thousands_sep_;}
+    virtual string      do_grouping()      const {return __grouping_;}
+    virtual string_type do_curr_symbol()   const {return __curr_symbol_;}
+    virtual string_type do_positive_sign() const {return __positive_sign_;}
+    virtual string_type do_negative_sign() const {return __negative_sign_;}
+    virtual int         do_frac_digits()   const {return __frac_digits_;}
+    virtual pattern     do_pos_format()    const {return __pos_format_;}
+    virtual pattern     do_neg_format()    const {return __neg_format_;}
+
+private:
+    char_type   __decimal_point_;
+    char_type   __thousands_sep_;
+    string      __grouping_;
+    string_type __curr_symbol_;
+    string_type __positive_sign_;
+    string_type __negative_sign_;
+    int         __frac_digits_;
+    pattern     __pos_format_;
+    pattern     __neg_format_;
+
+    void init(const char*);
+};
+
+template<> _LIBCPP_FUNC_VIS void moneypunct_byname<char, false>::init(const char*);
+template<> _LIBCPP_FUNC_VIS void moneypunct_byname<char, true>::init(const char*);
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS moneypunct_byname<char, false>)
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS moneypunct_byname<char, true>)
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template<> _LIBCPP_FUNC_VIS void moneypunct_byname<wchar_t, false>::init(const char*);
+template<> _LIBCPP_FUNC_VIS void moneypunct_byname<wchar_t, true>::init(const char*);
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS moneypunct_byname<wchar_t, false>)
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS moneypunct_byname<wchar_t, true>)
+#endif
+
+// money_get
+
+template <class _CharT>
+class __money_get
+{
+protected:
+    typedef _CharT                  char_type;
+    typedef basic_string<char_type> string_type;
+
+    _LIBCPP_INLINE_VISIBILITY __money_get() {}
+
+    static void __gather_info(bool __intl, const locale& __loc,
+                              money_base::pattern& __pat, char_type& __dp,
+                              char_type& __ts, string& __grp,
+                              string_type& __sym, string_type& __psn,
+                              string_type& __nsn, int& __fd);
+};
+
+template <class _CharT>
+void
+__money_get<_CharT>::__gather_info(bool __intl, const locale& __loc,
+                                   money_base::pattern& __pat, char_type& __dp,
+                                   char_type& __ts, string& __grp,
+                                   string_type& __sym, string_type& __psn,
+                                   string_type& __nsn, int& __fd)
+{
+    if (__intl)
+    {
+        const moneypunct<char_type, true>& __mp =
+            use_facet<moneypunct<char_type, true> >(__loc);
+        __pat = __mp.neg_format();
+        __nsn = __mp.negative_sign();
+        __psn = __mp.positive_sign();
+        __dp = __mp.decimal_point();
+        __ts = __mp.thousands_sep();
+        __grp = __mp.grouping();
+        __sym = __mp.curr_symbol();
+        __fd = __mp.frac_digits();
+    }
+    else
+    {
+        const moneypunct<char_type, false>& __mp =
+            use_facet<moneypunct<char_type, false> >(__loc);
+        __pat = __mp.neg_format();
+        __nsn = __mp.negative_sign();
+        __psn = __mp.positive_sign();
+        __dp = __mp.decimal_point();
+        __ts = __mp.thousands_sep();
+        __grp = __mp.grouping();
+        __sym = __mp.curr_symbol();
+        __fd = __mp.frac_digits();
+    }
+}
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __money_get<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __money_get<wchar_t>)
+#endif
+
+template <class _CharT, class _InputIterator = istreambuf_iterator<_CharT> >
+class _LIBCPP_TEMPLATE_VIS money_get
+    : public locale::facet,
+      private __money_get<_CharT>
+{
+public:
+    typedef _CharT                  char_type;
+    typedef _InputIterator          iter_type;
+    typedef basic_string<char_type> string_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit money_get(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, bool __intl, ios_base& __iob,
+                  ios_base::iostate& __err, long double& __v) const
+    {
+        return do_get(__b, __e, __intl, __iob, __err, __v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type get(iter_type __b, iter_type __e, bool __intl, ios_base& __iob,
+                  ios_base::iostate& __err, string_type& __v) const
+    {
+        return do_get(__b, __e, __intl, __iob, __err, __v);
+    }
+
+    static locale::id id;
+
+protected:
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~money_get() {}
+
+    virtual iter_type do_get(iter_type __b, iter_type __e, bool __intl,
+                             ios_base& __iob, ios_base::iostate& __err,
+                             long double& __v) const;
+    virtual iter_type do_get(iter_type __b, iter_type __e, bool __intl,
+                             ios_base& __iob, ios_base::iostate& __err,
+                             string_type& __v) const;
+
+private:
+    static bool __do_get(iter_type& __b, iter_type __e,
+                         bool __intl, const locale& __loc,
+                         ios_base::fmtflags __flags, ios_base::iostate& __err,
+                         bool& __neg, const ctype<char_type>& __ct,
+                         unique_ptr<char_type, void(*)(void*)>& __wb,
+                         char_type*& __wn, char_type* __we);
+};
+
+template <class _CharT, class _InputIterator>
+locale::id
+money_get<_CharT, _InputIterator>::id;
+
+_LIBCPP_FUNC_VIS void __do_nothing(void*);
+
+template <class _Tp>
+_LIBCPP_HIDDEN
+void
+__double_or_nothing(unique_ptr<_Tp, void(*)(void*)>& __b, _Tp*& __n, _Tp*& __e)
+{
+    bool __owns = __b.get_deleter() != __do_nothing;
+    size_t __cur_cap = static_cast<size_t>(__e-__b.get()) * sizeof(_Tp);
+    size_t __new_cap = __cur_cap < numeric_limits<size_t>::max() / 2 ?
+                       2 * __cur_cap : numeric_limits<size_t>::max();
+    if (__new_cap == 0)
+        __new_cap = sizeof(_Tp);
+    size_t __n_off = static_cast<size_t>(__n - __b.get());
+    _Tp* __t = (_Tp*)realloc(__owns ? __b.get() : 0, __new_cap);
+    if (__t == 0)
+        __throw_bad_alloc();
+    if (__owns)
+        __b.release();
+    __b = unique_ptr<_Tp, void(*)(void*)>(__t, free);
+    __new_cap /= sizeof(_Tp);
+    __n = __b.get() + __n_off;
+    __e = __b.get() + __new_cap;
+}
+
+// true == success
+template <class _CharT, class _InputIterator>
+bool
+money_get<_CharT, _InputIterator>::__do_get(iter_type& __b, iter_type __e,
+                                            bool __intl, const locale& __loc,
+                                            ios_base::fmtflags __flags,
+                                            ios_base::iostate& __err,
+                                            bool& __neg,
+                                            const ctype<char_type>& __ct,
+                                            unique_ptr<char_type, void(*)(void*)>& __wb,
+                                            char_type*& __wn, char_type* __we)
+{
+    if (__b == __e) {
+        __err |= ios_base::failbit;
+        return false;
+    }
+    const unsigned __bz = 100;
+    unsigned __gbuf[__bz];
+    unique_ptr<unsigned, void(*)(void*)> __gb(__gbuf, __do_nothing);
+    unsigned* __gn = __gb.get();
+    unsigned* __ge = __gn + __bz;
+    money_base::pattern __pat;
+    char_type __dp;
+    char_type __ts;
+    string __grp;
+    string_type __sym;
+    string_type __psn;
+    string_type __nsn;
+    // Capture the spaces read into money_base::{space,none} so they
+    // can be compared to initial spaces in __sym.
+    string_type __spaces;
+    int __fd;
+    __money_get<_CharT>::__gather_info(__intl, __loc, __pat, __dp, __ts, __grp,
+                                       __sym, __psn, __nsn, __fd);
+    const string_type* __trailing_sign = 0;
+    __wn = __wb.get();
+    for (unsigned __p = 0; __p < 4 && __b != __e; ++__p)
+    {
+        switch (__pat.field[__p])
+        {
+        case money_base::space:
+            if (__p != 3)
+            {
+                if (__ct.is(ctype_base::space, *__b))
+                    __spaces.push_back(*__b++);
+                else
+                {
+                    __err |= ios_base::failbit;
+                    return false;
+                }
+            }
+            _LIBCPP_FALLTHROUGH();
+        case money_base::none:
+            if (__p != 3)
+            {
+                while (__b != __e && __ct.is(ctype_base::space, *__b))
+                    __spaces.push_back(*__b++);
+            }
+            break;
+        case money_base::sign:
+            if (__psn.size() + __nsn.size() > 0)
+            {
+                if (__psn.size() == 0 || __nsn.size() == 0)
+                {   // sign is optional
+                    if (__psn.size() > 0)
+                    {   // __nsn.size() == 0
+                        if (*__b == __psn[0])
+                        {
+                            ++__b;
+                            if (__psn.size() > 1)
+                                __trailing_sign = &__psn;
+                        }
+                        else
+                            __neg = true;
+                    }
+                    else if (*__b == __nsn[0])  // __nsn.size() > 0 &&  __psn.size() == 0
+                    {
+                        ++__b;
+                        __neg = true;
+                        if (__nsn.size() > 1)
+                            __trailing_sign = &__nsn;
+                    }
+                }
+                else  // sign is required
+                {
+                    if (*__b == __psn[0])
+                    {
+                        ++__b;
+                        if (__psn.size() > 1)
+                            __trailing_sign = &__psn;
+                    }
+                    else if (*__b == __nsn[0])
+                    {
+                        ++__b;
+                        __neg = true;
+                        if (__nsn.size() > 1)
+                            __trailing_sign = &__nsn;
+                    }
+                    else
+                    {
+                        __err |= ios_base::failbit;
+                        return false;
+                    }
+                }
+            }
+            break;
+        case money_base::symbol:
+            {
+            bool __more_needed = __trailing_sign ||
+                                 (__p < 2)       ||
+                                 (__p == 2 && __pat.field[3] != static_cast<char>(money_base::none));
+            bool __sb = (__flags & ios_base::showbase) != 0;
+            if (__sb || __more_needed)
+            {
+                typename string_type::const_iterator __sym_space_end = __sym.begin();
+                if (__p > 0 && (__pat.field[__p - 1] == money_base::none ||
+                                __pat.field[__p - 1] == money_base::space)) {
+                    // Match spaces we've already read against spaces at
+                    // the beginning of __sym.
+                    while (__sym_space_end != __sym.end() &&
+                           __ct.is(ctype_base::space, *__sym_space_end))
+                        ++__sym_space_end;
+                    const size_t __num_spaces = __sym_space_end - __sym.begin();
+                    if (__num_spaces > __spaces.size() ||
+                        !equal(__spaces.end() - __num_spaces, __spaces.end(),
+                               __sym.begin())) {
+                        // No match. Put __sym_space_end back at the
+                        // beginning of __sym, which will prevent a
+                        // match in the next loop.
+                        __sym_space_end = __sym.begin();
+                    }
+                }
+                typename string_type::const_iterator __sym_curr_char = __sym_space_end;
+                while (__sym_curr_char != __sym.end() && __b != __e &&
+                       *__b == *__sym_curr_char) {
+                    ++__b;
+                    ++__sym_curr_char;
+                }
+                if (__sb && __sym_curr_char != __sym.end())
+                {
+                    __err |= ios_base::failbit;
+                    return false;
+                }
+            }
+            }
+            break;
+        case money_base::value:
+            {
+            unsigned __ng = 0;
+            for (; __b != __e; ++__b)
+            {
+                char_type __c = *__b;
+                if (__ct.is(ctype_base::digit, __c))
+                {
+                    if (__wn == __we)
+                        __double_or_nothing(__wb, __wn, __we);
+                    *__wn++ = __c;
+                    ++__ng;
+                }
+                else if (__grp.size() > 0 && __ng > 0 && __c == __ts)
+                {
+                    if (__gn == __ge)
+                        __double_or_nothing(__gb, __gn, __ge);
+                    *__gn++ = __ng;
+                    __ng = 0;
+                }
+                else
+                    break;
+            }
+            if (__gb.get() != __gn && __ng > 0)
+            {
+                if (__gn == __ge)
+                    __double_or_nothing(__gb, __gn, __ge);
+                *__gn++ = __ng;
+            }
+            if (__fd > 0)
+            {
+                if (__b == __e || *__b != __dp)
+                {
+                    __err |= ios_base::failbit;
+                    return false;
+                }
+                for (++__b; __fd > 0; --__fd, ++__b)
+                {
+                    if (__b == __e || !__ct.is(ctype_base::digit, *__b))
+                    {
+                        __err |= ios_base::failbit;
+                        return false;
+                    }
+                    if (__wn == __we)
+                        __double_or_nothing(__wb, __wn, __we);
+                    *__wn++ = *__b;
+                }
+            }
+            if (__wn == __wb.get())
+            {
+                __err |= ios_base::failbit;
+                return false;
+            }
+            }
+            break;
+        }
+    }
+    if (__trailing_sign)
+    {
+        for (unsigned __i = 1; __i < __trailing_sign->size(); ++__i, ++__b)
+        {
+            if (__b == __e || *__b != (*__trailing_sign)[__i])
+            {
+                __err |= ios_base::failbit;
+                return false;
+            }
+        }
+    }
+    if (__gb.get() != __gn)
+    {
+        ios_base::iostate __et = ios_base::goodbit;
+        __check_grouping(__grp, __gb.get(), __gn, __et);
+        if (__et)
+        {
+            __err |= ios_base::failbit;
+            return false;
+        }
+    }
+    return true;
+}
+
+template <class _CharT, class _InputIterator>
+_InputIterator
+money_get<_CharT, _InputIterator>::do_get(iter_type __b, iter_type __e,
+                                          bool __intl, ios_base& __iob,
+                                          ios_base::iostate& __err,
+                                          long double& __v) const
+{
+    const int __bz = 100;
+    char_type __wbuf[__bz];
+    unique_ptr<char_type, void(*)(void*)> __wb(__wbuf, __do_nothing);
+    char_type* __wn;
+    char_type* __we = __wbuf + __bz;
+    locale __loc = __iob.getloc();
+    const ctype<char_type>& __ct = use_facet<ctype<char_type> >(__loc);
+    bool __neg = false;
+    if (__do_get(__b, __e, __intl, __loc, __iob.flags(), __err, __neg, __ct,
+                 __wb, __wn, __we))
+    {
+        const char __src[] = "0123456789";
+        char_type __atoms[sizeof(__src)-1];
+        __ct.widen(__src, __src + (sizeof(__src)-1), __atoms);
+        char __nbuf[__bz];
+        char* __nc = __nbuf;
+        unique_ptr<char, void(*)(void*)> __h(nullptr, free);
+        if (__wn - __wb.get() > __bz-2)
+        {
+            __h.reset((char*)malloc(static_cast<size_t>(__wn - __wb.get() + 2)));
+            if (__h.get() == nullptr)
+                __throw_bad_alloc();
+            __nc = __h.get();
+        }
+        if (__neg)
+            *__nc++ = '-';
+        for (const char_type* __w = __wb.get(); __w < __wn; ++__w, ++__nc)
+            *__nc = __src[find(__atoms, _VSTD::end(__atoms), *__w) - __atoms];
+        *__nc = char();
+        if (sscanf(__nbuf, "%Lf", &__v) != 1)
+            __throw_runtime_error("money_get error");
+    }
+    if (__b == __e)
+        __err |= ios_base::eofbit;
+    return __b;
+}
+
+template <class _CharT, class _InputIterator>
+_InputIterator
+money_get<_CharT, _InputIterator>::do_get(iter_type __b, iter_type __e,
+                                          bool __intl, ios_base& __iob,
+                                          ios_base::iostate& __err,
+                                          string_type& __v) const
+{
+    const int __bz = 100;
+    char_type __wbuf[__bz];
+    unique_ptr<char_type, void(*)(void*)> __wb(__wbuf, __do_nothing);
+    char_type* __wn;
+    char_type* __we = __wbuf + __bz;
+    locale __loc = __iob.getloc();
+    const ctype<char_type>& __ct = use_facet<ctype<char_type> >(__loc);
+    bool __neg = false;
+    if (__do_get(__b, __e, __intl, __loc, __iob.flags(), __err, __neg, __ct,
+                 __wb, __wn, __we))
+    {
+        __v.clear();
+        if (__neg)
+            __v.push_back(__ct.widen('-'));
+        char_type __z = __ct.widen('0');
+        char_type* __w;
+        for (__w = __wb.get(); __w < __wn-1; ++__w)
+            if (*__w != __z)
+                break;
+        __v.append(__w, __wn);
+    }
+    if (__b == __e)
+        __err |= ios_base::eofbit;
+    return __b;
+}
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS money_get<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS money_get<wchar_t>)
+#endif
+
+// money_put
+
+template <class _CharT>
+class __money_put
+{
+protected:
+    typedef _CharT                  char_type;
+    typedef basic_string<char_type> string_type;
+
+    _LIBCPP_INLINE_VISIBILITY __money_put() {}
+
+    static void __gather_info(bool __intl, bool __neg, const locale& __loc,
+                              money_base::pattern& __pat, char_type& __dp,
+                              char_type& __ts, string& __grp,
+                              string_type& __sym, string_type& __sn,
+                              int& __fd);
+    static void __format(char_type* __mb, char_type*& __mi, char_type*& __me,
+                         ios_base::fmtflags __flags,
+                         const char_type* __db, const char_type* __de,
+                         const ctype<char_type>& __ct, bool __neg,
+                         const money_base::pattern& __pat, char_type __dp,
+                         char_type __ts, const string& __grp,
+                         const string_type& __sym, const string_type& __sn,
+                         int __fd);
+};
+
+template <class _CharT>
+void
+__money_put<_CharT>::__gather_info(bool __intl, bool __neg, const locale& __loc,
+                                   money_base::pattern& __pat, char_type& __dp,
+                                   char_type& __ts, string& __grp,
+                                   string_type& __sym, string_type& __sn,
+                                   int& __fd)
+{
+    if (__intl)
+    {
+        const moneypunct<char_type, true>& __mp =
+            use_facet<moneypunct<char_type, true> >(__loc);
+        if (__neg)
+        {
+            __pat = __mp.neg_format();
+            __sn = __mp.negative_sign();
+        }
+        else
+        {
+            __pat = __mp.pos_format();
+            __sn = __mp.positive_sign();
+        }
+        __dp = __mp.decimal_point();
+        __ts = __mp.thousands_sep();
+        __grp = __mp.grouping();
+        __sym = __mp.curr_symbol();
+        __fd = __mp.frac_digits();
+    }
+    else
+    {
+        const moneypunct<char_type, false>& __mp =
+            use_facet<moneypunct<char_type, false> >(__loc);
+        if (__neg)
+        {
+            __pat = __mp.neg_format();
+            __sn = __mp.negative_sign();
+        }
+        else
+        {
+            __pat = __mp.pos_format();
+            __sn = __mp.positive_sign();
+        }
+        __dp = __mp.decimal_point();
+        __ts = __mp.thousands_sep();
+        __grp = __mp.grouping();
+        __sym = __mp.curr_symbol();
+        __fd = __mp.frac_digits();
+    }
+}
+
+template <class _CharT>
+void
+__money_put<_CharT>::__format(char_type* __mb, char_type*& __mi, char_type*& __me,
+                              ios_base::fmtflags __flags,
+                              const char_type* __db, const char_type* __de,
+                              const ctype<char_type>& __ct, bool __neg,
+                              const money_base::pattern& __pat, char_type __dp,
+                              char_type __ts, const string& __grp,
+                              const string_type& __sym, const string_type& __sn,
+                              int __fd)
+{
+    __me = __mb;
+    for (unsigned __p = 0; __p < 4; ++__p)
+    {
+        switch (__pat.field[__p])
+        {
+        case money_base::none:
+            __mi = __me;
+            break;
+        case money_base::space:
+            __mi = __me;
+            *__me++ = __ct.widen(' ');
+            break;
+        case money_base::sign:
+            if (!__sn.empty())
+                *__me++ = __sn[0];
+            break;
+        case money_base::symbol:
+            if (!__sym.empty() && (__flags & ios_base::showbase))
+                __me = _VSTD::copy(__sym.begin(), __sym.end(), __me);
+            break;
+        case money_base::value:
+            {
+            // remember start of value so we can reverse it
+            char_type* __t = __me;
+            // find beginning of digits
+            if (__neg)
+                ++__db;
+            // find end of digits
+            const char_type* __d;
+            for (__d = __db; __d < __de; ++__d)
+                if (!__ct.is(ctype_base::digit, *__d))
+                    break;
+            // print fractional part
+            if (__fd > 0)
+            {
+                int __f;
+                for (__f = __fd; __d > __db && __f > 0; --__f)
+                    *__me++ = *--__d;
+                char_type __z = __f > 0 ? __ct.widen('0') : char_type();
+                for (; __f > 0; --__f)
+                    *__me++ = __z;
+                *__me++ = __dp;
+            }
+            // print units part
+            if (__d == __db)
+            {
+                *__me++ = __ct.widen('0');
+            }
+            else
+            {
+                unsigned __ng = 0;
+                unsigned __ig = 0;
+                unsigned __gl = __grp.empty() ? numeric_limits<unsigned>::max()
+                                              : static_cast<unsigned>(__grp[__ig]);
+                while (__d != __db)
+                {
+                    if (__ng == __gl)
+                    {
+                        *__me++ = __ts;
+                        __ng = 0;
+                        if (++__ig < __grp.size())
+                            __gl = __grp[__ig] == numeric_limits<char>::max() ?
+                                        numeric_limits<unsigned>::max() :
+                                        static_cast<unsigned>(__grp[__ig]);
+                    }
+                    *__me++ = *--__d;
+                    ++__ng;
+                }
+            }
+            // reverse it
+            reverse(__t, __me);
+            }
+            break;
+        }
+    }
+    // print rest of sign, if any
+    if (__sn.size() > 1)
+        __me = _VSTD::copy(__sn.begin()+1, __sn.end(), __me);
+    // set alignment
+    if ((__flags & ios_base::adjustfield) == ios_base::left)
+        __mi = __me;
+    else if ((__flags & ios_base::adjustfield) != ios_base::internal)
+        __mi = __mb;
+}
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __money_put<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __money_put<wchar_t>)
+#endif
+
+template <class _CharT, class _OutputIterator = ostreambuf_iterator<_CharT> >
+class _LIBCPP_TEMPLATE_VIS money_put
+    : public locale::facet,
+      private __money_put<_CharT>
+{
+public:
+    typedef _CharT                  char_type;
+    typedef _OutputIterator         iter_type;
+    typedef basic_string<char_type> string_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit money_put(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type put(iter_type __s, bool __intl, ios_base& __iob, char_type __fl,
+                  long double __units) const
+    {
+        return do_put(__s, __intl, __iob, __fl, __units);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iter_type put(iter_type __s, bool __intl, ios_base& __iob, char_type __fl,
+                  const string_type& __digits) const
+    {
+        return do_put(__s, __intl, __iob, __fl, __digits);
+    }
+
+    static locale::id id;
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    ~money_put() {}
+
+    virtual iter_type do_put(iter_type __s, bool __intl, ios_base& __iob,
+                             char_type __fl, long double __units) const;
+    virtual iter_type do_put(iter_type __s, bool __intl, ios_base& __iob,
+                             char_type __fl, const string_type& __digits) const;
+};
+
+template <class _CharT, class _OutputIterator>
+locale::id
+money_put<_CharT, _OutputIterator>::id;
+
+template <class _CharT, class _OutputIterator>
+_OutputIterator
+money_put<_CharT, _OutputIterator>::do_put(iter_type __s, bool __intl,
+                                           ios_base& __iob, char_type __fl,
+                                           long double __units) const
+{
+    // convert to char
+    const size_t __bs = 100;
+    char __buf[__bs];
+    char* __bb = __buf;
+    char_type __digits[__bs];
+    char_type* __db = __digits;
+    int __n = snprintf(__bb, __bs, "%.0Lf", __units);
+    unique_ptr<char, void(*)(void*)> __hn(nullptr, free);
+    unique_ptr<char_type, void(*)(void*)> __hd(0, free);
+    // secure memory for digit storage
+    if (static_cast<size_t>(__n) > __bs-1)
+    {
+        __n = __libcpp_asprintf_l(&__bb, _LIBCPP_GET_C_LOCALE, "%.0Lf", __units);
+        if (__n == -1)
+            __throw_bad_alloc();
+        __hn.reset(__bb);
+        __hd.reset((char_type*)malloc(static_cast<size_t>(__n) * sizeof(char_type)));
+        if (__hd == nullptr)
+            __throw_bad_alloc();
+        __db = __hd.get();
+    }
+    // gather info
+    locale __loc = __iob.getloc();
+    const ctype<char_type>& __ct = use_facet<ctype<char_type> >(__loc);
+    __ct.widen(__bb, __bb + __n, __db);
+    bool __neg = __n > 0 && __bb[0] == '-';
+    money_base::pattern __pat;
+    char_type __dp;
+    char_type __ts;
+    string __grp;
+    string_type __sym;
+    string_type __sn;
+    int __fd;
+    this->__gather_info(__intl, __neg, __loc, __pat, __dp, __ts, __grp, __sym, __sn, __fd);
+    // secure memory for formatting
+    char_type __mbuf[__bs];
+    char_type* __mb = __mbuf;
+    unique_ptr<char_type, void(*)(void*)> __hw(0, free);
+    size_t __exn = __n > __fd ?
+                   (static_cast<size_t>(__n) - static_cast<size_t>(__fd)) * 2 +
+                    __sn.size() + __sym.size() + static_cast<size_t>(__fd) + 1
+                 : __sn.size() + __sym.size() + static_cast<size_t>(__fd) + 2;
+    if (__exn > __bs)
+    {
+        __hw.reset((char_type*)malloc(__exn * sizeof(char_type)));
+        __mb = __hw.get();
+        if (__mb == 0)
+            __throw_bad_alloc();
+    }
+    // format
+    char_type* __mi;
+    char_type* __me;
+    this->__format(__mb, __mi, __me, __iob.flags(),
+                   __db, __db + __n, __ct,
+                   __neg, __pat, __dp, __ts, __grp, __sym, __sn, __fd);
+    return __pad_and_output(__s, __mb, __mi, __me, __iob, __fl);
+}
+
+template <class _CharT, class _OutputIterator>
+_OutputIterator
+money_put<_CharT, _OutputIterator>::do_put(iter_type __s, bool __intl,
+                                           ios_base& __iob, char_type __fl,
+                                           const string_type& __digits) const
+{
+    // gather info
+    locale __loc = __iob.getloc();
+    const ctype<char_type>& __ct = use_facet<ctype<char_type> >(__loc);
+    bool __neg = __digits.size() > 0 && __digits[0] == __ct.widen('-');
+    money_base::pattern __pat;
+    char_type __dp;
+    char_type __ts;
+    string __grp;
+    string_type __sym;
+    string_type __sn;
+    int __fd;
+    this->__gather_info(__intl, __neg, __loc, __pat, __dp, __ts, __grp, __sym, __sn, __fd);
+    // secure memory for formatting
+    char_type __mbuf[100];
+    char_type* __mb = __mbuf;
+    unique_ptr<char_type, void(*)(void*)> __h(0, free);
+    size_t __exn = static_cast<int>(__digits.size()) > __fd ?
+                   (__digits.size() - static_cast<size_t>(__fd)) * 2 +
+                    __sn.size() + __sym.size() + static_cast<size_t>(__fd) + 1
+                 : __sn.size() + __sym.size() + static_cast<size_t>(__fd) + 2;
+    if (__exn > 100)
+    {
+        __h.reset((char_type*)malloc(__exn * sizeof(char_type)));
+        __mb = __h.get();
+        if (__mb == 0)
+            __throw_bad_alloc();
+    }
+    // format
+    char_type* __mi;
+    char_type* __me;
+    this->__format(__mb, __mi, __me, __iob.flags(),
+                   __digits.data(), __digits.data() + __digits.size(), __ct,
+                   __neg, __pat, __dp, __ts, __grp, __sym, __sn, __fd);
+    return __pad_and_output(__s, __mb, __mi, __me, __iob, __fl);
+}
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS money_put<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS money_put<wchar_t>)
+#endif
+
+// messages
+
+class _LIBCPP_TYPE_VIS messages_base
+{
+public:
+    typedef ptrdiff_t catalog;
+
+    _LIBCPP_INLINE_VISIBILITY messages_base() {}
+};
+
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS messages
+    : public locale::facet,
+      public messages_base
+{
+public:
+    typedef _CharT               char_type;
+    typedef basic_string<_CharT> string_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit messages(size_t __refs = 0)
+        : locale::facet(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    catalog open(const basic_string<char>& __nm, const locale& __loc) const
+    {
+        return do_open(__nm, __loc);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    string_type get(catalog __c, int __set, int __msgid,
+                    const string_type& __dflt) const
+    {
+        return do_get(__c, __set, __msgid, __dflt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void close(catalog __c) const
+    {
+        do_close(__c);
+    }
+
+    static locale::id id;
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    ~messages() {}
+
+    virtual catalog do_open(const basic_string<char>&, const locale&) const;
+    virtual string_type do_get(catalog, int __set, int __msgid,
+                               const string_type& __dflt) const;
+    virtual void do_close(catalog) const;
+};
+
+template <class _CharT>
+locale::id
+messages<_CharT>::id;
+
+template <class _CharT>
+typename messages<_CharT>::catalog
+messages<_CharT>::do_open(const basic_string<char>& __nm, const locale&) const
+{
+#ifdef _LIBCPP_HAS_CATOPEN
+    catalog __cat = (catalog)catopen(__nm.c_str(), NL_CAT_LOCALE);
+    if (__cat != -1)
+        __cat = static_cast<catalog>((static_cast<size_t>(__cat) >> 1));
+    return __cat;
+#else // !_LIBCPP_HAS_CATOPEN
+    (void)__nm;
+    return -1;
+#endif // _LIBCPP_HAS_CATOPEN
+}
+
+template <class _CharT>
+typename messages<_CharT>::string_type
+messages<_CharT>::do_get(catalog __c, int __set, int __msgid,
+                         const string_type& __dflt) const
+{
+#ifdef _LIBCPP_HAS_CATOPEN
+    string __ndflt;
+    __narrow_to_utf8<sizeof(char_type)*__CHAR_BIT__>()(back_inserter(__ndflt),
+                                                       __dflt.c_str(),
+                                                       __dflt.c_str() + __dflt.size());
+    if (__c != -1)
+        __c <<= 1;
+    nl_catd __cat = (nl_catd)__c;
+    char* __n = catgets(__cat, __set, __msgid, __ndflt.c_str());
+    string_type __w;
+    __widen_from_utf8<sizeof(char_type)*__CHAR_BIT__>()(back_inserter(__w),
+                                                        __n, __n + _VSTD::strlen(__n));
+    return __w;
+#else // !_LIBCPP_HAS_CATOPEN
+    (void)__c;
+    (void)__set;
+    (void)__msgid;
+    return __dflt;
+#endif // _LIBCPP_HAS_CATOPEN
+}
+
+template <class _CharT>
+void
+messages<_CharT>::do_close(catalog __c) const
+{
+#ifdef _LIBCPP_HAS_CATOPEN
+    if (__c != -1)
+        __c <<= 1;
+    nl_catd __cat = (nl_catd)__c;
+    catclose(__cat);
+#else // !_LIBCPP_HAS_CATOPEN
+    (void)__c;
+#endif // _LIBCPP_HAS_CATOPEN
+}
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS messages<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS messages<wchar_t>)
+#endif
+
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS messages_byname
+    : public messages<_CharT>
+{
+public:
+    typedef messages_base::catalog catalog;
+    typedef basic_string<_CharT> string_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit messages_byname(const char*, size_t __refs = 0)
+        : messages<_CharT>(__refs) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit messages_byname(const string&, size_t __refs = 0)
+        : messages<_CharT>(__refs) {}
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    ~messages_byname() {}
+};
+
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS messages_byname<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE_EVEN_IN_DEBUG_MODE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS messages_byname<wchar_t>)
+#endif
+
+template<class _Codecvt, class _Elem = wchar_t,
+         class _Wide_alloc = allocator<_Elem>,
+         class _Byte_alloc = allocator<char> >
+class _LIBCPP_TEMPLATE_VIS wstring_convert
+{
+public:
+    typedef basic_string<char, char_traits<char>, _Byte_alloc>   byte_string;
+    typedef basic_string<_Elem, char_traits<_Elem>, _Wide_alloc> wide_string;
+    typedef typename _Codecvt::state_type                        state_type;
+    typedef typename wide_string::traits_type::int_type          int_type;
+
+private:
+    byte_string __byte_err_string_;
+    wide_string __wide_err_string_;
+    _Codecvt* __cvtptr_;
+    state_type __cvtstate_;
+    size_t __cvtcount_;
+
+    wstring_convert(const wstring_convert& __wc);
+    wstring_convert& operator=(const wstring_convert& __wc);
+public:
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    wstring_convert() : wstring_convert(new _Codecvt) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit wstring_convert(_Codecvt* __pcvt);
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_EXPLICIT_AFTER_CXX11
+    wstring_convert(_Codecvt* __pcvt = new _Codecvt);
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    wstring_convert(_Codecvt* __pcvt, state_type __state);
+    _LIBCPP_EXPLICIT_AFTER_CXX11 wstring_convert(const byte_string& __byte_err,
+                    const wide_string& __wide_err = wide_string());
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    wstring_convert(wstring_convert&& __wc);
+#endif
+    ~wstring_convert();
+
+    _LIBCPP_INLINE_VISIBILITY
+    wide_string from_bytes(char __byte)
+        {return from_bytes(&__byte, &__byte+1);}
+    _LIBCPP_INLINE_VISIBILITY
+    wide_string from_bytes(const char* __ptr)
+        {return from_bytes(__ptr, __ptr + char_traits<char>::length(__ptr));}
+    _LIBCPP_INLINE_VISIBILITY
+    wide_string from_bytes(const byte_string& __str)
+        {return from_bytes(__str.data(), __str.data() + __str.size());}
+    wide_string from_bytes(const char* __first, const char* __last);
+
+    _LIBCPP_INLINE_VISIBILITY
+    byte_string to_bytes(_Elem __wchar)
+        {return to_bytes(&__wchar, &__wchar+1);}
+    _LIBCPP_INLINE_VISIBILITY
+    byte_string to_bytes(const _Elem* __wptr)
+        {return to_bytes(__wptr, __wptr + char_traits<_Elem>::length(__wptr));}
+    _LIBCPP_INLINE_VISIBILITY
+    byte_string to_bytes(const wide_string& __wstr)
+        {return to_bytes(__wstr.data(), __wstr.data() + __wstr.size());}
+    byte_string to_bytes(const _Elem* __first, const _Elem* __last);
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t converted() const _NOEXCEPT {return __cvtcount_;}
+    _LIBCPP_INLINE_VISIBILITY
+    state_type state() const {return __cvtstate_;}
+};
+
+template<class _Codecvt, class _Elem, class _Wide_alloc, class _Byte_alloc>
+inline
+wstring_convert<_Codecvt, _Elem, _Wide_alloc, _Byte_alloc>::
+    wstring_convert(_Codecvt* __pcvt)
+        : __cvtptr_(__pcvt), __cvtstate_(), __cvtcount_(0)
+{
+}
+
+template<class _Codecvt, class _Elem, class _Wide_alloc, class _Byte_alloc>
+inline
+wstring_convert<_Codecvt, _Elem, _Wide_alloc, _Byte_alloc>::
+    wstring_convert(_Codecvt* __pcvt, state_type __state)
+        : __cvtptr_(__pcvt), __cvtstate_(__state), __cvtcount_(0)
+{
+}
+
+template<class _Codecvt, class _Elem, class _Wide_alloc, class _Byte_alloc>
+wstring_convert<_Codecvt, _Elem, _Wide_alloc, _Byte_alloc>::
+    wstring_convert(const byte_string& __byte_err, const wide_string& __wide_err)
+        : __byte_err_string_(__byte_err), __wide_err_string_(__wide_err),
+          __cvtstate_(), __cvtcount_(0)
+{
+    __cvtptr_ = new _Codecvt;
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _Codecvt, class _Elem, class _Wide_alloc, class _Byte_alloc>
+inline
+wstring_convert<_Codecvt, _Elem, _Wide_alloc, _Byte_alloc>::
+    wstring_convert(wstring_convert&& __wc)
+        : __byte_err_string_(_VSTD::move(__wc.__byte_err_string_)),
+          __wide_err_string_(_VSTD::move(__wc.__wide_err_string_)),
+          __cvtptr_(__wc.__cvtptr_),
+          __cvtstate_(__wc.__cvtstate_), __cvtcount_(__wc.__cvtcount_)
+{
+    __wc.__cvtptr_ = nullptr;
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template<class _Codecvt, class _Elem, class _Wide_alloc, class _Byte_alloc>
+wstring_convert<_Codecvt, _Elem, _Wide_alloc, _Byte_alloc>::~wstring_convert()
+{
+    delete __cvtptr_;
+}
+
+template<class _Codecvt, class _Elem, class _Wide_alloc, class _Byte_alloc>
+typename wstring_convert<_Codecvt, _Elem, _Wide_alloc, _Byte_alloc>::wide_string
+wstring_convert<_Codecvt, _Elem, _Wide_alloc, _Byte_alloc>::
+    from_bytes(const char* __frm, const char* __frm_end)
+{
+    __cvtcount_ = 0;
+    if (__cvtptr_ != nullptr)
+    {
+        wide_string __ws(2*(__frm_end - __frm), _Elem());
+        if (__frm != __frm_end)
+            __ws.resize(__ws.capacity());
+        codecvt_base::result __r = codecvt_base::ok;
+        state_type __st = __cvtstate_;
+        if (__frm != __frm_end)
+        {
+            _Elem* __to = &__ws[0];
+            _Elem* __to_end = __to + __ws.size();
+            const char* __frm_nxt;
+            do
+            {
+                _Elem* __to_nxt;
+                __r = __cvtptr_->in(__st, __frm, __frm_end, __frm_nxt,
+                                          __to, __to_end, __to_nxt);
+                __cvtcount_ += __frm_nxt - __frm;
+                if (__frm_nxt == __frm)
+                {
+                    __r = codecvt_base::error;
+                }
+                else if (__r == codecvt_base::noconv)
+                {
+                    __ws.resize(__to - &__ws[0]);
+                    // This only gets executed if _Elem is char
+                    __ws.append((const _Elem*)__frm, (const _Elem*)__frm_end);
+                    __frm = __frm_nxt;
+                    __r = codecvt_base::ok;
+                }
+                else if (__r == codecvt_base::ok)
+                {
+                    __ws.resize(__to_nxt - &__ws[0]);
+                    __frm = __frm_nxt;
+                }
+                else if (__r == codecvt_base::partial)
+                {
+                    ptrdiff_t __s = __to_nxt - &__ws[0];
+                    __ws.resize(2 * __s);
+                    __to = &__ws[0] + __s;
+                    __to_end = &__ws[0] + __ws.size();
+                    __frm = __frm_nxt;
+                }
+            } while (__r == codecvt_base::partial && __frm_nxt < __frm_end);
+        }
+        if (__r == codecvt_base::ok)
+            return __ws;
+    }
+
+    if (__wide_err_string_.empty())
+        __throw_range_error("wstring_convert: from_bytes error");
+
+    return __wide_err_string_;
+}
+
+template<class _Codecvt, class _Elem, class _Wide_alloc, class _Byte_alloc>
+typename wstring_convert<_Codecvt, _Elem, _Wide_alloc, _Byte_alloc>::byte_string
+wstring_convert<_Codecvt, _Elem, _Wide_alloc, _Byte_alloc>::
+    to_bytes(const _Elem* __frm, const _Elem* __frm_end)
+{
+    __cvtcount_ = 0;
+    if (__cvtptr_ != nullptr)
+    {
+        byte_string __bs(2*(__frm_end - __frm), char());
+        if (__frm != __frm_end)
+            __bs.resize(__bs.capacity());
+        codecvt_base::result __r = codecvt_base::ok;
+        state_type __st = __cvtstate_;
+        if (__frm != __frm_end)
+        {
+            char* __to = &__bs[0];
+            char* __to_end = __to + __bs.size();
+            const _Elem* __frm_nxt;
+            do
+            {
+                char* __to_nxt;
+                __r = __cvtptr_->out(__st, __frm, __frm_end, __frm_nxt,
+                                           __to, __to_end, __to_nxt);
+                __cvtcount_ += __frm_nxt - __frm;
+                if (__frm_nxt == __frm)
+                {
+                    __r = codecvt_base::error;
+                }
+                else if (__r == codecvt_base::noconv)
+                {
+                    __bs.resize(__to - &__bs[0]);
+                    // This only gets executed if _Elem is char
+                    __bs.append((const char*)__frm, (const char*)__frm_end);
+                    __frm = __frm_nxt;
+                    __r = codecvt_base::ok;
+                }
+                else if (__r == codecvt_base::ok)
+                {
+                    __bs.resize(__to_nxt - &__bs[0]);
+                    __frm = __frm_nxt;
+                }
+                else if (__r == codecvt_base::partial)
+                {
+                    ptrdiff_t __s = __to_nxt - &__bs[0];
+                    __bs.resize(2 * __s);
+                    __to = &__bs[0] + __s;
+                    __to_end = &__bs[0] + __bs.size();
+                    __frm = __frm_nxt;
+                }
+            } while (__r == codecvt_base::partial && __frm_nxt < __frm_end);
+        }
+        if (__r == codecvt_base::ok)
+        {
+            size_t __s = __bs.size();
+            __bs.resize(__bs.capacity());
+            char* __to = &__bs[0] + __s;
+            char* __to_end = __to + __bs.size();
+            do
+            {
+                char* __to_nxt;
+                __r = __cvtptr_->unshift(__st, __to, __to_end, __to_nxt);
+                if (__r == codecvt_base::noconv)
+                {
+                    __bs.resize(__to - &__bs[0]);
+                    __r = codecvt_base::ok;
+                }
+                else if (__r == codecvt_base::ok)
+                {
+                    __bs.resize(__to_nxt - &__bs[0]);
+                }
+                else if (__r == codecvt_base::partial)
+                {
+                    ptrdiff_t __sp = __to_nxt - &__bs[0];
+                    __bs.resize(2 * __sp);
+                    __to = &__bs[0] + __sp;
+                    __to_end = &__bs[0] + __bs.size();
+                }
+            } while (__r == codecvt_base::partial);
+            if (__r == codecvt_base::ok)
+                return __bs;
+        }
+    }
+
+    if (__byte_err_string_.empty())
+        __throw_range_error("wstring_convert: to_bytes error");
+
+    return __byte_err_string_;
+}
+
+template <class _Codecvt, class _Elem = wchar_t, class _Tr = char_traits<_Elem> >
+class _LIBCPP_TEMPLATE_VIS wbuffer_convert
+    : public basic_streambuf<_Elem, _Tr>
+{
+public:
+    // types:
+    typedef _Elem                          char_type;
+    typedef _Tr                            traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+    typedef typename _Codecvt::state_type  state_type;
+
+private:
+    char*       __extbuf_;
+    const char* __extbufnext_;
+    const char* __extbufend_;
+    char __extbuf_min_[8];
+    size_t __ebs_;
+    char_type* __intbuf_;
+    size_t __ibs_;
+    streambuf* __bufptr_;
+    _Codecvt* __cv_;
+    state_type __st_;
+    ios_base::openmode __cm_;
+    bool __owns_eb_;
+    bool __owns_ib_;
+    bool __always_noconv_;
+
+    wbuffer_convert(const wbuffer_convert&);
+    wbuffer_convert& operator=(const wbuffer_convert&);
+
+public:
+#ifndef _LIBCPP_CXX03_LANG
+    wbuffer_convert() : wbuffer_convert(nullptr) {}
+    explicit wbuffer_convert(streambuf* __bytebuf,
+                             _Codecvt* __pcvt = new _Codecvt,
+                             state_type __state = state_type());
+#else
+    _LIBCPP_EXPLICIT_AFTER_CXX11
+    wbuffer_convert(streambuf* __bytebuf = nullptr,
+                    _Codecvt* __pcvt = new _Codecvt,
+                    state_type __state = state_type());
+#endif
+
+    ~wbuffer_convert();
+
+    _LIBCPP_INLINE_VISIBILITY
+    streambuf* rdbuf() const {return __bufptr_;}
+    _LIBCPP_INLINE_VISIBILITY
+    streambuf* rdbuf(streambuf* __bytebuf)
+    {
+        streambuf* __r = __bufptr_;
+        __bufptr_ = __bytebuf;
+        return __r;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    state_type state() const {return __st_;}
+
+protected:
+    virtual int_type underflow();
+    virtual int_type pbackfail(int_type __c = traits_type::eof());
+    virtual int_type overflow (int_type __c = traits_type::eof());
+    virtual basic_streambuf<char_type, traits_type>* setbuf(char_type* __s,
+                                                            streamsize __n);
+    virtual pos_type seekoff(off_type __off, ios_base::seekdir __way,
+                             ios_base::openmode __wch = ios_base::in | ios_base::out);
+    virtual pos_type seekpos(pos_type __sp,
+                             ios_base::openmode __wch = ios_base::in | ios_base::out);
+    virtual int sync();
+
+private:
+    bool __read_mode();
+    void __write_mode();
+    wbuffer_convert* __close();
+};
+
+template <class _Codecvt, class _Elem, class _Tr>
+wbuffer_convert<_Codecvt, _Elem, _Tr>::
+    wbuffer_convert(streambuf* __bytebuf, _Codecvt* __pcvt, state_type __state)
+    : __extbuf_(nullptr),
+      __extbufnext_(nullptr),
+      __extbufend_(nullptr),
+      __ebs_(0),
+      __intbuf_(0),
+      __ibs_(0),
+      __bufptr_(__bytebuf),
+      __cv_(__pcvt),
+      __st_(__state),
+      __cm_(0),
+      __owns_eb_(false),
+      __owns_ib_(false),
+      __always_noconv_(__cv_ ? __cv_->always_noconv() : false)
+{
+    setbuf(0, 4096);
+}
+
+template <class _Codecvt, class _Elem, class _Tr>
+wbuffer_convert<_Codecvt, _Elem, _Tr>::~wbuffer_convert()
+{
+    __close();
+    delete __cv_;
+    if (__owns_eb_)
+        delete [] __extbuf_;
+    if (__owns_ib_)
+        delete [] __intbuf_;
+}
+
+template <class _Codecvt, class _Elem, class _Tr>
+typename wbuffer_convert<_Codecvt, _Elem, _Tr>::int_type
+wbuffer_convert<_Codecvt, _Elem, _Tr>::underflow()
+{
+    if (__cv_ == 0 || __bufptr_ == 0)
+        return traits_type::eof();
+    bool __initial = __read_mode();
+    char_type __1buf;
+    if (this->gptr() == 0)
+        this->setg(&__1buf, &__1buf+1, &__1buf+1);
+    const size_t __unget_sz = __initial ? 0 : min<size_t>((this->egptr() - this->eback()) / 2, 4);
+    int_type __c = traits_type::eof();
+    if (this->gptr() == this->egptr())
+    {
+        _VSTD::memmove(this->eback(), this->egptr() - __unget_sz, __unget_sz * sizeof(char_type));
+        if (__always_noconv_)
+        {
+            streamsize __nmemb = static_cast<streamsize>(this->egptr() - this->eback() - __unget_sz);
+            __nmemb = __bufptr_->sgetn((char*)this->eback() + __unget_sz, __nmemb);
+            if (__nmemb != 0)
+            {
+                this->setg(this->eback(),
+                           this->eback() + __unget_sz,
+                           this->eback() + __unget_sz + __nmemb);
+                __c = *this->gptr();
+            }
+        }
+        else
+        {
+             _LIBCPP_ASSERT(!(__extbufnext_ == NULL && (__extbufend_ != __extbufnext_)), "underflow moving from NULL" );
+             if (__extbufend_ != __extbufnext_)
+                _VSTD::memmove(__extbuf_, __extbufnext_, __extbufend_ - __extbufnext_);
+            __extbufnext_ = __extbuf_ + (__extbufend_ - __extbufnext_);
+            __extbufend_ = __extbuf_ + (__extbuf_ == __extbuf_min_ ? sizeof(__extbuf_min_) : __ebs_);
+            streamsize __nmemb = _VSTD::min(static_cast<streamsize>(this->egptr() - this->eback() - __unget_sz),
+                                 static_cast<streamsize>(__extbufend_ - __extbufnext_));
+            codecvt_base::result __r;
+            // FIXME: Do we ever need to restore the state here?
+            //state_type __svs = __st_;
+            streamsize __nr = __bufptr_->sgetn(const_cast<char*>(__extbufnext_), __nmemb);
+            if (__nr != 0)
+            {
+                __extbufend_ = __extbufnext_ + __nr;
+                char_type*  __inext;
+                __r = __cv_->in(__st_, __extbuf_, __extbufend_, __extbufnext_,
+                                       this->eback() + __unget_sz,
+                                       this->egptr(), __inext);
+                if (__r == codecvt_base::noconv)
+                {
+                    this->setg((char_type*)__extbuf_, (char_type*)__extbuf_,
+                               (char_type*) const_cast<char *>(__extbufend_));
+                    __c = *this->gptr();
+                }
+                else if (__inext != this->eback() + __unget_sz)
+                {
+                    this->setg(this->eback(), this->eback() + __unget_sz, __inext);
+                    __c = *this->gptr();
+                }
+            }
+        }
+    }
+    else
+        __c = *this->gptr();
+    if (this->eback() == &__1buf)
+        this->setg(0, 0, 0);
+    return __c;
+}
+
+template <class _Codecvt, class _Elem, class _Tr>
+typename wbuffer_convert<_Codecvt, _Elem, _Tr>::int_type
+wbuffer_convert<_Codecvt, _Elem, _Tr>::pbackfail(int_type __c)
+{
+    if (__cv_ != 0 && __bufptr_ != 0 && this->eback() < this->gptr())
+    {
+        if (traits_type::eq_int_type(__c, traits_type::eof()))
+        {
+            this->gbump(-1);
+            return traits_type::not_eof(__c);
+        }
+        if (traits_type::eq(traits_type::to_char_type(__c), this->gptr()[-1]))
+        {
+            this->gbump(-1);
+            *this->gptr() = traits_type::to_char_type(__c);
+            return __c;
+        }
+    }
+    return traits_type::eof();
+}
+
+template <class _Codecvt, class _Elem, class _Tr>
+typename wbuffer_convert<_Codecvt, _Elem, _Tr>::int_type
+wbuffer_convert<_Codecvt, _Elem, _Tr>::overflow(int_type __c)
+{
+    if (__cv_ == 0 || __bufptr_ == 0)
+        return traits_type::eof();
+    __write_mode();
+    char_type __1buf;
+    char_type* __pb_save = this->pbase();
+    char_type* __epb_save = this->epptr();
+    if (!traits_type::eq_int_type(__c, traits_type::eof()))
+    {
+        if (this->pptr() == 0)
+            this->setp(&__1buf, &__1buf+1);
+        *this->pptr() = traits_type::to_char_type(__c);
+        this->pbump(1);
+    }
+    if (this->pptr() != this->pbase())
+    {
+        if (__always_noconv_)
+        {
+            streamsize __nmemb = static_cast<streamsize>(this->pptr() - this->pbase());
+            if (__bufptr_->sputn((const char*)this->pbase(), __nmemb) != __nmemb)
+                return traits_type::eof();
+        }
+        else
+        {
+            char* __extbe = __extbuf_;
+            codecvt_base::result __r;
+            do
+            {
+                const char_type* __e;
+                __r = __cv_->out(__st_, this->pbase(), this->pptr(), __e,
+                                        __extbuf_, __extbuf_ + __ebs_, __extbe);
+                if (__e == this->pbase())
+                    return traits_type::eof();
+                if (__r == codecvt_base::noconv)
+                {
+                    streamsize __nmemb = static_cast<size_t>(this->pptr() - this->pbase());
+                    if (__bufptr_->sputn((const char*)this->pbase(), __nmemb) != __nmemb)
+                        return traits_type::eof();
+                }
+                else if (__r == codecvt_base::ok || __r == codecvt_base::partial)
+                {
+                    streamsize __nmemb = static_cast<size_t>(__extbe - __extbuf_);
+                    if (__bufptr_->sputn(__extbuf_, __nmemb) != __nmemb)
+                        return traits_type::eof();
+                    if (__r == codecvt_base::partial)
+                    {
+                        this->setp(const_cast<char_type *>(__e), this->pptr());
+                        this->__pbump(this->epptr() - this->pbase());
+                    }
+                }
+                else
+                    return traits_type::eof();
+            } while (__r == codecvt_base::partial);
+        }
+        this->setp(__pb_save, __epb_save);
+    }
+    return traits_type::not_eof(__c);
+}
+
+template <class _Codecvt, class _Elem, class _Tr>
+basic_streambuf<_Elem, _Tr>*
+wbuffer_convert<_Codecvt, _Elem, _Tr>::setbuf(char_type* __s, streamsize __n)
+{
+    this->setg(0, 0, 0);
+    this->setp(0, 0);
+    if (__owns_eb_)
+        delete [] __extbuf_;
+    if (__owns_ib_)
+        delete [] __intbuf_;
+    __ebs_ = __n;
+    if (__ebs_ > sizeof(__extbuf_min_))
+    {
+        if (__always_noconv_ && __s)
+        {
+            __extbuf_ = (char*)__s;
+            __owns_eb_ = false;
+        }
+        else
+        {
+            __extbuf_ = new char[__ebs_];
+            __owns_eb_ = true;
+        }
+    }
+    else
+    {
+        __extbuf_ = __extbuf_min_;
+        __ebs_ = sizeof(__extbuf_min_);
+        __owns_eb_ = false;
+    }
+    if (!__always_noconv_)
+    {
+        __ibs_ = max<streamsize>(__n, sizeof(__extbuf_min_));
+        if (__s && __ibs_ >= sizeof(__extbuf_min_))
+        {
+            __intbuf_ = __s;
+            __owns_ib_ = false;
+        }
+        else
+        {
+            __intbuf_ = new char_type[__ibs_];
+            __owns_ib_ = true;
+        }
+    }
+    else
+    {
+        __ibs_ = 0;
+        __intbuf_ = 0;
+        __owns_ib_ = false;
+    }
+    return this;
+}
+
+template <class _Codecvt, class _Elem, class _Tr>
+typename wbuffer_convert<_Codecvt, _Elem, _Tr>::pos_type
+wbuffer_convert<_Codecvt, _Elem, _Tr>::seekoff(off_type __off, ios_base::seekdir __way,
+                                        ios_base::openmode __om)
+{
+    int __width = __cv_->encoding();
+    if (__cv_ == 0 || __bufptr_ == 0 || (__width <= 0 && __off != 0) || sync())
+        return pos_type(off_type(-1));
+    // __width > 0 || __off == 0, now check __way
+    if (__way != ios_base::beg && __way != ios_base::cur && __way != ios_base::end)
+        return pos_type(off_type(-1));
+    pos_type __r = __bufptr_->pubseekoff(__width * __off, __way, __om);
+    __r.state(__st_);
+    return __r;
+}
+
+template <class _Codecvt, class _Elem, class _Tr>
+typename wbuffer_convert<_Codecvt, _Elem, _Tr>::pos_type
+wbuffer_convert<_Codecvt, _Elem, _Tr>::seekpos(pos_type __sp, ios_base::openmode __wch)
+{
+    if (__cv_ == 0 || __bufptr_ == 0 || sync())
+        return pos_type(off_type(-1));
+    if (__bufptr_->pubseekpos(__sp, __wch) == pos_type(off_type(-1)))
+        return pos_type(off_type(-1));
+    return __sp;
+}
+
+template <class _Codecvt, class _Elem, class _Tr>
+int
+wbuffer_convert<_Codecvt, _Elem, _Tr>::sync()
+{
+    if (__cv_ == 0 || __bufptr_ == 0)
+        return 0;
+    if (__cm_ & ios_base::out)
+    {
+        if (this->pptr() != this->pbase())
+            if (overflow() == traits_type::eof())
+                return -1;
+        codecvt_base::result __r;
+        do
+        {
+            char* __extbe;
+            __r = __cv_->unshift(__st_, __extbuf_, __extbuf_ + __ebs_, __extbe);
+            streamsize __nmemb = static_cast<streamsize>(__extbe - __extbuf_);
+            if (__bufptr_->sputn(__extbuf_, __nmemb) != __nmemb)
+                return -1;
+        } while (__r == codecvt_base::partial);
+        if (__r == codecvt_base::error)
+            return -1;
+        if (__bufptr_->pubsync())
+            return -1;
+    }
+    else if (__cm_ & ios_base::in)
+    {
+        off_type __c;
+        if (__always_noconv_)
+            __c = this->egptr() - this->gptr();
+        else
+        {
+            int __width = __cv_->encoding();
+            __c = __extbufend_ - __extbufnext_;
+            if (__width > 0)
+                __c += __width * (this->egptr() - this->gptr());
+            else
+            {
+                if (this->gptr() != this->egptr())
+                {
+                    reverse(this->gptr(), this->egptr());
+                    codecvt_base::result __r;
+                    const char_type* __e = this->gptr();
+                    char* __extbe;
+                    do
+                    {
+                        __r = __cv_->out(__st_, __e, this->egptr(), __e,
+                                         __extbuf_, __extbuf_ + __ebs_, __extbe);
+                        switch (__r)
+                        {
+                        case codecvt_base::noconv:
+                            __c += this->egptr() - this->gptr();
+                            break;
+                        case codecvt_base::ok:
+                        case codecvt_base::partial:
+                            __c += __extbe - __extbuf_;
+                            break;
+                        default:
+                            return -1;
+                        }
+                    } while (__r == codecvt_base::partial);
+                }
+            }
+        }
+        if (__bufptr_->pubseekoff(-__c, ios_base::cur, __cm_) == pos_type(off_type(-1)))
+            return -1;
+        this->setg(0, 0, 0);
+        __cm_ = 0;
+    }
+    return 0;
+}
+
+template <class _Codecvt, class _Elem, class _Tr>
+bool
+wbuffer_convert<_Codecvt, _Elem, _Tr>::__read_mode()
+{
+    if (!(__cm_ & ios_base::in))
+    {
+        this->setp(0, 0);
+        if (__always_noconv_)
+            this->setg((char_type*)__extbuf_,
+                       (char_type*)__extbuf_ + __ebs_,
+                       (char_type*)__extbuf_ + __ebs_);
+        else
+            this->setg(__intbuf_, __intbuf_ + __ibs_, __intbuf_ + __ibs_);
+        __cm_ = ios_base::in;
+        return true;
+    }
+    return false;
+}
+
+template <class _Codecvt, class _Elem, class _Tr>
+void
+wbuffer_convert<_Codecvt, _Elem, _Tr>::__write_mode()
+{
+    if (!(__cm_ & ios_base::out))
+    {
+        this->setg(0, 0, 0);
+        if (__ebs_ > sizeof(__extbuf_min_))
+        {
+            if (__always_noconv_)
+                this->setp((char_type*)__extbuf_,
+                           (char_type*)__extbuf_ + (__ebs_ - 1));
+            else
+                this->setp(__intbuf_, __intbuf_ + (__ibs_ - 1));
+        }
+        else
+            this->setp(0, 0);
+        __cm_ = ios_base::out;
+    }
+}
+
+template <class _Codecvt, class _Elem, class _Tr>
+wbuffer_convert<_Codecvt, _Elem, _Tr>*
+wbuffer_convert<_Codecvt, _Elem, _Tr>::__close()
+{
+    wbuffer_convert* __rt = nullptr;
+    if (__cv_ != nullptr && __bufptr_ != nullptr)
+    {
+        __rt = this;
+        if ((__cm_ & ios_base::out) && sync())
+            __rt = nullptr;
+    }
+    return __rt;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_LOCALE
diff --git a/contrib/libs/cxxsupp/libcxx/include/locale.h b/contrib/libs/cxxsupp/libcxx/include/locale.h
new file mode 100644
index 00000000000..52c452001d3
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/locale.h
@@ -0,0 +1,52 @@
+// -*- C++ -*-
+//===---------------------------- locale.h --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_LOCALE_H
+#define _LIBCPP_LOCALE_H
+
+/*
+    locale.h synopsis
+
+Macros:
+
+    LC_ALL
+    LC_COLLATE
+    LC_CTYPE
+    LC_MONETARY
+    LC_NUMERIC
+    LC_TIME
+
+Types:
+
+    lconv
+
+Functions:
+
+   setlocale
+   localeconv
+
+*/
+
+#include <__config>
+
+#if defined(_LIBCPP_HAS_NO_LOCALIZATION)
+#   error "The Localization library is not supported since libc++ has been configured with LIBCXX_ENABLE_LOCALIZATION disabled"
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#   pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(locale.h)
+#else
+#include_next <locale.h>
+#endif
+
+#endif // _LIBCPP_LOCALE_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/map b/contrib/libs/cxxsupp/libcxx/include/map
new file mode 100644
index 00000000000..c78a7ee31a4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/map
@@ -0,0 +1,2293 @@
+// -*- C++ -*-
+//===----------------------------- map ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_MAP
+#define _LIBCPP_MAP
+
+/*
+
+    map synopsis
+
+namespace std
+{
+
+template <class Key, class T, class Compare = less<Key>,
+          class Allocator = allocator<pair<const Key, T>>>
+class map
+{
+public:
+    // types:
+    typedef Key                                      key_type;
+    typedef T                                        mapped_type;
+    typedef pair<const key_type, mapped_type>        value_type;
+    typedef Compare                                  key_compare;
+    typedef Allocator                                allocator_type;
+    typedef typename allocator_type::reference       reference;
+    typedef typename allocator_type::const_reference const_reference;
+    typedef typename allocator_type::pointer         pointer;
+    typedef typename allocator_type::const_pointer   const_pointer;
+    typedef typename allocator_type::size_type       size_type;
+    typedef typename allocator_type::difference_type difference_type;
+
+    typedef implementation-defined                   iterator;
+    typedef implementation-defined                   const_iterator;
+    typedef std::reverse_iterator<iterator>          reverse_iterator;
+    typedef std::reverse_iterator<const_iterator>    const_reverse_iterator;
+    typedef unspecified                              node_type;              // C++17
+    typedef INSERT_RETURN_TYPE<iterator, node_type>  insert_return_type;     // C++17
+
+    class value_compare
+    {
+        friend class map;
+    protected:
+        key_compare comp;
+
+        value_compare(key_compare c);
+    public:
+        typedef bool result_type;  // deprecated in C++17, removed in C++20
+        typedef value_type first_argument_type;  // deprecated in C++17, removed in C++20
+        typedef value_type second_argument_type;  // deprecated in C++17, removed in C++20
+        bool operator()(const value_type& x, const value_type& y) const;
+    };
+
+    // construct/copy/destroy:
+    map()
+        noexcept(
+            is_nothrow_default_constructible<allocator_type>::value &&
+            is_nothrow_default_constructible<key_compare>::value &&
+            is_nothrow_copy_constructible<key_compare>::value);
+    explicit map(const key_compare& comp);
+    map(const key_compare& comp, const allocator_type& a);
+    template <class InputIterator>
+        map(InputIterator first, InputIterator last,
+            const key_compare& comp = key_compare());
+    template <class InputIterator>
+        map(InputIterator first, InputIterator last,
+            const key_compare& comp, const allocator_type& a);
+    map(const map& m);
+    map(map&& m)
+        noexcept(
+            is_nothrow_move_constructible<allocator_type>::value &&
+            is_nothrow_move_constructible<key_compare>::value);
+    explicit map(const allocator_type& a);
+    map(const map& m, const allocator_type& a);
+    map(map&& m, const allocator_type& a);
+    map(initializer_list<value_type> il, const key_compare& comp = key_compare());
+    map(initializer_list<value_type> il, const key_compare& comp, const allocator_type& a);
+    template <class InputIterator>
+        map(InputIterator first, InputIterator last, const allocator_type& a)
+            : map(first, last, Compare(), a) {}  // C++14
+    map(initializer_list<value_type> il, const allocator_type& a)
+        : map(il, Compare(), a) {}  // C++14
+   ~map();
+
+    map& operator=(const map& m);
+    map& operator=(map&& m)
+        noexcept(
+            allocator_type::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<allocator_type>::value &&
+            is_nothrow_move_assignable<key_compare>::value);
+    map& operator=(initializer_list<value_type> il);
+
+    // iterators:
+          iterator begin() noexcept;
+    const_iterator begin() const noexcept;
+          iterator end() noexcept;
+    const_iterator end()   const noexcept;
+
+          reverse_iterator rbegin() noexcept;
+    const_reverse_iterator rbegin() const noexcept;
+          reverse_iterator rend() noexcept;
+    const_reverse_iterator rend()   const noexcept;
+
+    const_iterator         cbegin()  const noexcept;
+    const_iterator         cend()    const noexcept;
+    const_reverse_iterator crbegin() const noexcept;
+    const_reverse_iterator crend()   const noexcept;
+
+    // capacity:
+    bool      empty()    const noexcept;
+    size_type size()     const noexcept;
+    size_type max_size() const noexcept;
+
+    // element access:
+    mapped_type& operator[](const key_type& k);
+    mapped_type& operator[](key_type&& k);
+
+          mapped_type& at(const key_type& k);
+    const mapped_type& at(const key_type& k) const;
+
+    // modifiers:
+    template <class... Args>
+        pair<iterator, bool> emplace(Args&&... args);
+    template <class... Args>
+        iterator emplace_hint(const_iterator position, Args&&... args);
+    pair<iterator, bool> insert(const value_type& v);
+    pair<iterator, bool> insert(      value_type&& v);                                // C++17
+    template <class P>
+        pair<iterator, bool> insert(P&& p);
+    iterator insert(const_iterator position, const value_type& v);
+    iterator insert(const_iterator position,       value_type&& v);                   // C++17
+    template <class P>
+        iterator insert(const_iterator position, P&& p);
+    template <class InputIterator>
+        void insert(InputIterator first, InputIterator last);
+    void insert(initializer_list<value_type> il);
+
+    node_type extract(const_iterator position);                                       // C++17
+    node_type extract(const key_type& x);                                             // C++17
+    insert_return_type insert(node_type&& nh);                                        // C++17
+    iterator insert(const_iterator hint, node_type&& nh);                             // C++17
+
+    template <class... Args>
+        pair<iterator, bool> try_emplace(const key_type& k, Args&&... args);          // C++17
+    template <class... Args>
+        pair<iterator, bool> try_emplace(key_type&& k, Args&&... args);               // C++17
+    template <class... Args>
+        iterator try_emplace(const_iterator hint, const key_type& k, Args&&... args); // C++17
+    template <class... Args>
+        iterator try_emplace(const_iterator hint, key_type&& k, Args&&... args);      // C++17
+    template <class M>
+        pair<iterator, bool> insert_or_assign(const key_type& k, M&& obj);            // C++17
+    template <class M>
+        pair<iterator, bool> insert_or_assign(key_type&& k, M&& obj);                 // C++17
+    template <class M>
+        iterator insert_or_assign(const_iterator hint, const key_type& k, M&& obj);   // C++17
+    template <class M>
+        iterator insert_or_assign(const_iterator hint, key_type&& k, M&& obj);        // C++17
+
+    iterator  erase(const_iterator position);
+    iterator  erase(iterator position); // C++14
+    size_type erase(const key_type& k);
+    iterator  erase(const_iterator first, const_iterator last);
+    void clear() noexcept;
+
+    template<class C2>
+      void merge(map<Key, T, C2, Allocator>& source);         // C++17
+    template<class C2>
+      void merge(map<Key, T, C2, Allocator>&& source);        // C++17
+    template<class C2>
+      void merge(multimap<Key, T, C2, Allocator>& source);    // C++17
+    template<class C2>
+      void merge(multimap<Key, T, C2, Allocator>&& source);   // C++17
+
+    void swap(map& m)
+        noexcept(allocator_traits<allocator_type>::is_always_equal::value &&
+            is_nothrow_swappable<key_compare>::value); // C++17
+
+    // observers:
+    allocator_type get_allocator() const noexcept;
+    key_compare    key_comp()      const;
+    value_compare  value_comp()    const;
+
+    // map operations:
+          iterator find(const key_type& k);
+    const_iterator find(const key_type& k) const;
+    template<typename K>
+        iterator find(const K& x);              // C++14
+    template<typename K>
+        const_iterator find(const K& x) const;  // C++14
+
+    template<typename K>
+      size_type count(const K& x) const;        // C++14
+    size_type      count(const key_type& k) const;
+
+        bool contains(const key_type& x) const; // C++20
+    template<class K> bool contains(const K& x) const; // C++20
+
+          iterator lower_bound(const key_type& k);
+    const_iterator lower_bound(const key_type& k) const;
+    template<typename K>
+        iterator lower_bound(const K& x);              // C++14
+    template<typename K>
+        const_iterator lower_bound(const K& x) const;  // C++14
+
+          iterator upper_bound(const key_type& k);
+    const_iterator upper_bound(const key_type& k) const;
+    template<typename K>
+        iterator upper_bound(const K& x);              // C++14
+    template<typename K>
+        const_iterator upper_bound(const K& x) const;  // C++14
+
+    pair<iterator,iterator>             equal_range(const key_type& k);
+    pair<const_iterator,const_iterator> equal_range(const key_type& k) const;
+    template<typename K>
+        pair<iterator,iterator>             equal_range(const K& x);        // C++14
+    template<typename K>
+        pair<const_iterator,const_iterator> equal_range(const K& x) const;  // C++14
+};
+
+template <class Key, class T, class Compare, class Allocator>
+bool
+operator==(const map<Key, T, Compare, Allocator>& x,
+           const map<Key, T, Compare, Allocator>& y);
+
+template <class Key, class T, class Compare, class Allocator>
+bool
+operator< (const map<Key, T, Compare, Allocator>& x,
+           const map<Key, T, Compare, Allocator>& y);
+
+template <class Key, class T, class Compare, class Allocator>
+bool
+operator!=(const map<Key, T, Compare, Allocator>& x,
+           const map<Key, T, Compare, Allocator>& y);
+
+template <class Key, class T, class Compare, class Allocator>
+bool
+operator> (const map<Key, T, Compare, Allocator>& x,
+           const map<Key, T, Compare, Allocator>& y);
+
+template <class Key, class T, class Compare, class Allocator>
+bool
+operator>=(const map<Key, T, Compare, Allocator>& x,
+           const map<Key, T, Compare, Allocator>& y);
+
+template <class Key, class T, class Compare, class Allocator>
+bool
+operator<=(const map<Key, T, Compare, Allocator>& x,
+           const map<Key, T, Compare, Allocator>& y);
+
+// specialized algorithms:
+template <class Key, class T, class Compare, class Allocator>
+void
+swap(map<Key, T, Compare, Allocator>& x, map<Key, T, Compare, Allocator>& y)
+    noexcept(noexcept(x.swap(y)));
+
+template <class Key, class T, class Compare, class Allocator, class Predicate>
+typename map<Key, T, Compare, Allocator>::size_type
+erase_if(map<Key, T, Compare, Allocator>& c, Predicate pred);  // C++20
+
+
+template <class Key, class T, class Compare = less<Key>,
+          class Allocator = allocator<pair<const Key, T>>>
+class multimap
+{
+public:
+    // types:
+    typedef Key                                      key_type;
+    typedef T                                        mapped_type;
+    typedef pair<const key_type,mapped_type>         value_type;
+    typedef Compare                                  key_compare;
+    typedef Allocator                                allocator_type;
+    typedef typename allocator_type::reference       reference;
+    typedef typename allocator_type::const_reference const_reference;
+    typedef typename allocator_type::size_type       size_type;
+    typedef typename allocator_type::difference_type difference_type;
+    typedef typename allocator_type::pointer         pointer;
+    typedef typename allocator_type::const_pointer   const_pointer;
+
+    typedef implementation-defined                   iterator;
+    typedef implementation-defined                   const_iterator;
+    typedef std::reverse_iterator<iterator>          reverse_iterator;
+    typedef std::reverse_iterator<const_iterator>    const_reverse_iterator;
+    typedef unspecified                              node_type;              // C++17
+
+    class value_compare
+    {
+        friend class multimap;
+    protected:
+        key_compare comp;
+        value_compare(key_compare c);
+    public:
+        typedef bool result_type;  // deprecated in C++17, removed in C++20
+        typedef value_type first_argument_type;  // deprecated in C++17, removed in C++20
+        typedef value_type second_argument_type;  // deprecated in C++17, removed in C++20
+        bool operator()(const value_type& x, const value_type& y) const;
+    };
+
+    // construct/copy/destroy:
+    multimap()
+        noexcept(
+            is_nothrow_default_constructible<allocator_type>::value &&
+            is_nothrow_default_constructible<key_compare>::value &&
+            is_nothrow_copy_constructible<key_compare>::value);
+    explicit multimap(const key_compare& comp);
+    multimap(const key_compare& comp, const allocator_type& a);
+    template <class InputIterator>
+        multimap(InputIterator first, InputIterator last, const key_compare& comp);
+    template <class InputIterator>
+        multimap(InputIterator first, InputIterator last, const key_compare& comp,
+                 const allocator_type& a);
+    multimap(const multimap& m);
+    multimap(multimap&& m)
+        noexcept(
+            is_nothrow_move_constructible<allocator_type>::value &&
+            is_nothrow_move_constructible<key_compare>::value);
+    explicit multimap(const allocator_type& a);
+    multimap(const multimap& m, const allocator_type& a);
+    multimap(multimap&& m, const allocator_type& a);
+    multimap(initializer_list<value_type> il, const key_compare& comp = key_compare());
+    multimap(initializer_list<value_type> il, const key_compare& comp,
+             const allocator_type& a);
+    template <class InputIterator>
+        multimap(InputIterator first, InputIterator last, const allocator_type& a)
+            : multimap(first, last, Compare(), a) {} // C++14
+    multimap(initializer_list<value_type> il, const allocator_type& a)
+        : multimap(il, Compare(), a) {} // C++14
+    ~multimap();
+
+    multimap& operator=(const multimap& m);
+    multimap& operator=(multimap&& m)
+        noexcept(
+            allocator_type::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<allocator_type>::value &&
+            is_nothrow_move_assignable<key_compare>::value);
+    multimap& operator=(initializer_list<value_type> il);
+
+    // iterators:
+          iterator begin() noexcept;
+    const_iterator begin() const noexcept;
+          iterator end() noexcept;
+    const_iterator end()   const noexcept;
+
+          reverse_iterator rbegin() noexcept;
+    const_reverse_iterator rbegin() const noexcept;
+          reverse_iterator rend() noexcept;
+    const_reverse_iterator rend()   const noexcept;
+
+    const_iterator         cbegin()  const noexcept;
+    const_iterator         cend()    const noexcept;
+    const_reverse_iterator crbegin() const noexcept;
+    const_reverse_iterator crend()   const noexcept;
+
+    // capacity:
+    bool      empty()    const noexcept;
+    size_type size()     const noexcept;
+    size_type max_size() const noexcept;
+
+    // modifiers:
+    template <class... Args>
+        iterator emplace(Args&&... args);
+    template <class... Args>
+        iterator emplace_hint(const_iterator position, Args&&... args);
+    iterator insert(const value_type& v);
+    iterator insert(      value_type&& v);                                            // C++17
+    template <class P>
+        iterator insert(P&& p);
+    iterator insert(const_iterator position, const value_type& v);
+    iterator insert(const_iterator position,       value_type&& v);                   // C++17
+    template <class P>
+        iterator insert(const_iterator position, P&& p);
+    template <class InputIterator>
+        void insert(InputIterator first, InputIterator last);
+    void insert(initializer_list<value_type> il);
+
+    node_type extract(const_iterator position);                                       // C++17
+    node_type extract(const key_type& x);                                             // C++17
+    iterator insert(node_type&& nh);                                                  // C++17
+    iterator insert(const_iterator hint, node_type&& nh);                             // C++17
+
+    iterator  erase(const_iterator position);
+    iterator  erase(iterator position); // C++14
+    size_type erase(const key_type& k);
+    iterator  erase(const_iterator first, const_iterator last);
+    void clear() noexcept;
+
+    template<class C2>
+      void merge(multimap<Key, T, C2, Allocator>& source);    // C++17
+    template<class C2>
+      void merge(multimap<Key, T, C2, Allocator>&& source);   // C++17
+    template<class C2>
+      void merge(map<Key, T, C2, Allocator>& source);         // C++17
+    template<class C2>
+      void merge(map<Key, T, C2, Allocator>&& source);        // C++17
+
+    void swap(multimap& m)
+        noexcept(allocator_traits<allocator_type>::is_always_equal::value &&
+            is_nothrow_swappable<key_compare>::value); // C++17
+
+    // observers:
+    allocator_type get_allocator() const noexcept;
+    key_compare    key_comp()      const;
+    value_compare  value_comp()    const;
+
+    // map operations:
+          iterator find(const key_type& k);
+    const_iterator find(const key_type& k) const;
+    template<typename K>
+        iterator find(const K& x);              // C++14
+    template<typename K>
+        const_iterator find(const K& x) const;  // C++14
+
+    template<typename K>
+      size_type count(const K& x) const;        // C++14
+    size_type      count(const key_type& k) const;
+
+        bool contains(const key_type& x) const; // C++20
+    template<class K> bool contains(const K& x) const; // C++20
+
+          iterator lower_bound(const key_type& k);
+    const_iterator lower_bound(const key_type& k) const;
+    template<typename K>
+        iterator lower_bound(const K& x);              // C++14
+    template<typename K>
+        const_iterator lower_bound(const K& x) const;  // C++14
+
+          iterator upper_bound(const key_type& k);
+    const_iterator upper_bound(const key_type& k) const;
+    template<typename K>
+        iterator upper_bound(const K& x);              // C++14
+    template<typename K>
+        const_iterator upper_bound(const K& x) const;  // C++14
+
+    pair<iterator,iterator>             equal_range(const key_type& k);
+    pair<const_iterator,const_iterator> equal_range(const key_type& k) const;
+    template<typename K>
+        pair<iterator,iterator>             equal_range(const K& x);        // C++14
+    template<typename K>
+        pair<const_iterator,const_iterator> equal_range(const K& x) const;  // C++14
+};
+
+template <class Key, class T, class Compare, class Allocator>
+bool
+operator==(const multimap<Key, T, Compare, Allocator>& x,
+           const multimap<Key, T, Compare, Allocator>& y);
+
+template <class Key, class T, class Compare, class Allocator>
+bool
+operator< (const multimap<Key, T, Compare, Allocator>& x,
+           const multimap<Key, T, Compare, Allocator>& y);
+
+template <class Key, class T, class Compare, class Allocator>
+bool
+operator!=(const multimap<Key, T, Compare, Allocator>& x,
+           const multimap<Key, T, Compare, Allocator>& y);
+
+template <class Key, class T, class Compare, class Allocator>
+bool
+operator> (const multimap<Key, T, Compare, Allocator>& x,
+           const multimap<Key, T, Compare, Allocator>& y);
+
+template <class Key, class T, class Compare, class Allocator>
+bool
+operator>=(const multimap<Key, T, Compare, Allocator>& x,
+           const multimap<Key, T, Compare, Allocator>& y);
+
+template <class Key, class T, class Compare, class Allocator>
+bool
+operator<=(const multimap<Key, T, Compare, Allocator>& x,
+           const multimap<Key, T, Compare, Allocator>& y);
+
+// specialized algorithms:
+template <class Key, class T, class Compare, class Allocator>
+void
+swap(multimap<Key, T, Compare, Allocator>& x,
+     multimap<Key, T, Compare, Allocator>& y)
+    noexcept(noexcept(x.swap(y)));
+
+template <class Key, class T, class Compare, class Allocator, class Predicate>
+typename multimap<Key, T, Compare, Allocator>::size_type
+erase_if(multimap<Key, T, Compare, Allocator>& c, Predicate pred);  // C++20
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__functional/is_transparent.h>
+#include <__node_handle>
+#include <__tree>
+#include <__utility/forward.h>
+#include <compare>
+#include <functional>
+#include <initializer_list>
+#include <iterator> // __libcpp_erase_if_container
+#include <memory>
+#include <type_traits>
+#include <utility>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Key, class _CP, class _Compare,
+          bool = is_empty<_Compare>::value && !__libcpp_is_final<_Compare>::value>
+class __map_value_compare
+    : private _Compare
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __map_value_compare()
+        _NOEXCEPT_(is_nothrow_default_constructible<_Compare>::value)
+        : _Compare() {}
+    _LIBCPP_INLINE_VISIBILITY
+    __map_value_compare(_Compare c)
+        _NOEXCEPT_(is_nothrow_copy_constructible<_Compare>::value)
+        : _Compare(c) {}
+    _LIBCPP_INLINE_VISIBILITY
+    const _Compare& key_comp() const _NOEXCEPT {return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _CP& __x, const _CP& __y) const
+        {return static_cast<const _Compare&>(*this)(__x.__get_value().first, __y.__get_value().first);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _CP& __x, const _Key& __y) const
+        {return static_cast<const _Compare&>(*this)(__x.__get_value().first, __y);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Key& __x, const _CP& __y) const
+        {return static_cast<const _Compare&>(*this)(__x, __y.__get_value().first);}
+    void swap(__map_value_compare& __y)
+        _NOEXCEPT_(__is_nothrow_swappable<_Compare>::value)
+    {
+      using _VSTD::swap;
+      swap(static_cast<_Compare&>(*this), static_cast<_Compare&>(__y));
+    }
+
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _K2& __x, const _CP& __y) const
+        {return static_cast<const _Compare&>(*this)(__x, __y.__get_value().first);}
+
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _CP& __x, const _K2& __y) const
+        {return static_cast<const _Compare&>(*this)(__x.__get_value().first, __y);}
+#endif
+};
+
+template <class _Key, class _CP, class _Compare>
+class __map_value_compare<_Key, _CP, _Compare, false>
+{
+    _Compare comp;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __map_value_compare()
+        _NOEXCEPT_(is_nothrow_default_constructible<_Compare>::value)
+        : comp() {}
+    _LIBCPP_INLINE_VISIBILITY
+    __map_value_compare(_Compare c)
+        _NOEXCEPT_(is_nothrow_copy_constructible<_Compare>::value)
+        : comp(c) {}
+    _LIBCPP_INLINE_VISIBILITY
+    const _Compare& key_comp() const _NOEXCEPT {return comp;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _CP& __x, const _CP& __y) const
+        {return comp(__x.__get_value().first, __y.__get_value().first);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _CP& __x, const _Key& __y) const
+        {return comp(__x.__get_value().first, __y);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Key& __x, const _CP& __y) const
+        {return comp(__x, __y.__get_value().first);}
+    void swap(__map_value_compare& __y)
+        _NOEXCEPT_(__is_nothrow_swappable<_Compare>::value)
+    {
+        using _VSTD::swap;
+        swap(comp, __y.comp);
+    }
+
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _K2& __x, const _CP& __y) const
+        {return comp(__x, __y.__get_value().first);}
+
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _CP& __x, const _K2& __y) const
+        {return comp(__x.__get_value().first, __y);}
+#endif
+};
+
+template <class _Key, class _CP, class _Compare, bool __b>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(__map_value_compare<_Key, _CP, _Compare, __b>& __x,
+     __map_value_compare<_Key, _CP, _Compare, __b>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+template <class _Allocator>
+class __map_node_destructor
+{
+    typedef _Allocator                          allocator_type;
+    typedef allocator_traits<allocator_type>    __alloc_traits;
+
+public:
+    typedef typename __alloc_traits::pointer    pointer;
+
+private:
+    allocator_type& __na_;
+
+    __map_node_destructor& operator=(const __map_node_destructor&);
+
+public:
+    bool __first_constructed;
+    bool __second_constructed;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __map_node_destructor(allocator_type& __na) _NOEXCEPT
+        : __na_(__na),
+          __first_constructed(false),
+          __second_constructed(false)
+        {}
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    __map_node_destructor(__tree_node_destructor<allocator_type>&& __x) _NOEXCEPT
+        : __na_(__x.__na_),
+          __first_constructed(__x.__value_constructed),
+          __second_constructed(__x.__value_constructed)
+        {
+            __x.__value_constructed = false;
+        }
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator()(pointer __p) _NOEXCEPT
+    {
+        if (__second_constructed)
+            __alloc_traits::destroy(__na_, _VSTD::addressof(__p->__value_.__get_value().second));
+        if (__first_constructed)
+            __alloc_traits::destroy(__na_, _VSTD::addressof(__p->__value_.__get_value().first));
+        if (__p)
+            __alloc_traits::deallocate(__na_, __p, 1);
+    }
+};
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+    class map;
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+    class multimap;
+template <class _TreeIterator> class __map_const_iterator;
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Key, class _Tp>
+struct _LIBCPP_STANDALONE_DEBUG __value_type
+{
+    typedef _Key                                     key_type;
+    typedef _Tp                                      mapped_type;
+    typedef pair<const key_type, mapped_type>        value_type;
+    typedef pair<key_type&, mapped_type&>            __nc_ref_pair_type;
+    typedef pair<key_type&&, mapped_type&&>          __nc_rref_pair_type;
+
+private:
+    value_type __cc;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    value_type& __get_value()
+    {
+#if _LIBCPP_STD_VER > 14
+        return *_VSTD::launder(_VSTD::addressof(__cc));
+#else
+        return __cc;
+#endif
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const value_type& __get_value() const
+    {
+#if _LIBCPP_STD_VER > 14
+        return *_VSTD::launder(_VSTD::addressof(__cc));
+#else
+        return __cc;
+#endif
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __nc_ref_pair_type __ref()
+    {
+        value_type& __v = __get_value();
+        return __nc_ref_pair_type(const_cast<key_type&>(__v.first), __v.second);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __nc_rref_pair_type __move()
+    {
+        value_type& __v = __get_value();
+        return __nc_rref_pair_type(
+            _VSTD::move(const_cast<key_type&>(__v.first)),
+            _VSTD::move(__v.second));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __value_type& operator=(const __value_type& __v)
+    {
+        __ref() = __v.__get_value();
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __value_type& operator=(__value_type&& __v)
+    {
+        __ref() = __v.__move();
+        return *this;
+    }
+
+    template <class _ValueTp,
+              class = typename enable_if<
+                    __is_same_uncvref<_ValueTp, value_type>::value
+                 >::type
+             >
+    _LIBCPP_INLINE_VISIBILITY
+    __value_type& operator=(_ValueTp&& __v)
+    {
+        __ref() = _VSTD::forward<_ValueTp>(__v);
+        return *this;
+    }
+
+private:
+    __value_type() = delete;
+    ~__value_type() = delete;
+    __value_type(const __value_type&) = delete;
+    __value_type(__value_type&&) = delete;
+};
+
+#else
+
+template <class _Key, class _Tp>
+struct __value_type
+{
+    typedef _Key                                     key_type;
+    typedef _Tp                                      mapped_type;
+    typedef pair<const key_type, mapped_type>        value_type;
+
+private:
+    value_type __cc;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    value_type& __get_value() { return __cc; }
+    _LIBCPP_INLINE_VISIBILITY
+    const value_type& __get_value() const { return __cc; }
+
+private:
+   __value_type();
+   __value_type(__value_type const&);
+   __value_type& operator=(__value_type const&);
+   ~__value_type();
+};
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp>
+struct __extract_key_value_types;
+
+template <class _Key, class _Tp>
+struct __extract_key_value_types<__value_type<_Key, _Tp> >
+{
+  typedef _Key const __key_type;
+  typedef _Tp        __mapped_type;
+};
+
+template <class _TreeIterator>
+class _LIBCPP_TEMPLATE_VIS __map_iterator
+{
+    typedef typename _TreeIterator::_NodeTypes                   _NodeTypes;
+    typedef typename _TreeIterator::__pointer_traits             __pointer_traits;
+
+    _TreeIterator __i_;
+
+public:
+    typedef bidirectional_iterator_tag                           iterator_category;
+    typedef typename _NodeTypes::__map_value_type                value_type;
+    typedef typename _TreeIterator::difference_type              difference_type;
+    typedef value_type&                                          reference;
+    typedef typename _NodeTypes::__map_value_type_pointer        pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __map_iterator() _NOEXCEPT {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __map_iterator(_TreeIterator __i) _NOEXCEPT : __i_(__i) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {return __i_->__get_value();}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {return pointer_traits<pointer>::pointer_to(__i_->__get_value());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __map_iterator& operator++() {++__i_; return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    __map_iterator operator++(int)
+    {
+        __map_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __map_iterator& operator--() {--__i_; return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    __map_iterator operator--(int)
+    {
+        __map_iterator __t(*this);
+        --(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __map_iterator& __x, const __map_iterator& __y)
+        {return __x.__i_ == __y.__i_;}
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __map_iterator& __x, const __map_iterator& __y)
+        {return __x.__i_ != __y.__i_;}
+
+    template <class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS map;
+    template <class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS multimap;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __map_const_iterator;
+};
+
+template <class _TreeIterator>
+class _LIBCPP_TEMPLATE_VIS __map_const_iterator
+{
+    typedef typename _TreeIterator::_NodeTypes                   _NodeTypes;
+    typedef typename _TreeIterator::__pointer_traits             __pointer_traits;
+
+    _TreeIterator __i_;
+
+public:
+    typedef bidirectional_iterator_tag                           iterator_category;
+    typedef typename _NodeTypes::__map_value_type                value_type;
+    typedef typename _TreeIterator::difference_type              difference_type;
+    typedef const value_type&                                    reference;
+    typedef typename _NodeTypes::__const_map_value_type_pointer  pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __map_const_iterator() _NOEXCEPT {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __map_const_iterator(_TreeIterator __i) _NOEXCEPT : __i_(__i) {}
+    _LIBCPP_INLINE_VISIBILITY
+    __map_const_iterator(__map_iterator<
+        typename _TreeIterator::__non_const_iterator> __i) _NOEXCEPT
+        : __i_(__i.__i_) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {return __i_->__get_value();}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {return pointer_traits<pointer>::pointer_to(__i_->__get_value());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __map_const_iterator& operator++() {++__i_; return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    __map_const_iterator operator++(int)
+    {
+        __map_const_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __map_const_iterator& operator--() {--__i_; return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    __map_const_iterator operator--(int)
+    {
+        __map_const_iterator __t(*this);
+        --(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __map_const_iterator& __x, const __map_const_iterator& __y)
+        {return __x.__i_ == __y.__i_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __map_const_iterator& __x, const __map_const_iterator& __y)
+        {return __x.__i_ != __y.__i_;}
+
+    template <class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS map;
+    template <class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS multimap;
+    template <class, class, class> friend class _LIBCPP_TEMPLATE_VIS __tree_const_iterator;
+};
+
+template <class _Key, class _Tp, class _Compare = less<_Key>,
+          class _Allocator = allocator<pair<const _Key, _Tp> > >
+class _LIBCPP_TEMPLATE_VIS map
+{
+public:
+    // types:
+    typedef _Key                                     key_type;
+    typedef _Tp                                      mapped_type;
+    typedef pair<const key_type, mapped_type>        value_type;
+    typedef __identity_t<_Compare>                   key_compare;
+    typedef __identity_t<_Allocator>                 allocator_type;
+    typedef value_type&                              reference;
+    typedef const value_type&                        const_reference;
+
+    static_assert((is_same<typename allocator_type::value_type, value_type>::value),
+                  "Allocator::value_type must be same type as value_type");
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+    class _LIBCPP_TEMPLATE_VIS value_compare
+#if defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+        : public binary_function<value_type, value_type, bool>
+#endif
+    {
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+        friend class map;
+    protected:
+        key_compare comp;
+
+        _LIBCPP_INLINE_VISIBILITY value_compare(key_compare c) : comp(c) {}
+    public:
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+        _LIBCPP_DEPRECATED_IN_CXX17 typedef bool result_type;
+        _LIBCPP_DEPRECATED_IN_CXX17 typedef value_type first_argument_type;
+        _LIBCPP_DEPRECATED_IN_CXX17 typedef value_type second_argument_type;
+#endif
+        _LIBCPP_INLINE_VISIBILITY
+        bool operator()(const value_type& __x, const value_type& __y) const
+            {return comp(__x.first, __y.first);}
+    };
+
+private:
+
+    typedef _VSTD::__value_type<key_type, mapped_type>             __value_type;
+    typedef __map_value_compare<key_type, __value_type, key_compare> __vc;
+    typedef typename __rebind_alloc_helper<allocator_traits<allocator_type>,
+                                                 __value_type>::type __allocator_type;
+    typedef __tree<__value_type, __vc, __allocator_type>   __base;
+    typedef typename __base::__node_traits                 __node_traits;
+    typedef allocator_traits<allocator_type>               __alloc_traits;
+
+    __base __tree_;
+
+public:
+    typedef typename __alloc_traits::pointer               pointer;
+    typedef typename __alloc_traits::const_pointer         const_pointer;
+    typedef typename __alloc_traits::size_type             size_type;
+    typedef typename __alloc_traits::difference_type       difference_type;
+    typedef __map_iterator<typename __base::iterator>             iterator;
+    typedef __map_const_iterator<typename __base::const_iterator> const_iterator;
+    typedef _VSTD::reverse_iterator<iterator>               reverse_iterator;
+    typedef _VSTD::reverse_iterator<const_iterator>         const_reverse_iterator;
+
+#if _LIBCPP_STD_VER > 14
+    typedef __map_node_handle<typename __base::__node, allocator_type> node_type;
+    typedef __insert_return_type<iterator, node_type> insert_return_type;
+#endif
+
+    template <class _Key2, class _Value2, class _Comp2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS map;
+    template <class _Key2, class _Value2, class _Comp2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS multimap;
+
+    _LIBCPP_INLINE_VISIBILITY
+    map()
+        _NOEXCEPT_(
+            is_nothrow_default_constructible<allocator_type>::value &&
+            is_nothrow_default_constructible<key_compare>::value &&
+            is_nothrow_copy_constructible<key_compare>::value)
+        : __tree_(__vc(key_compare())) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit map(const key_compare& __comp)
+        _NOEXCEPT_(
+            is_nothrow_default_constructible<allocator_type>::value &&
+            is_nothrow_copy_constructible<key_compare>::value)
+        : __tree_(__vc(__comp)) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit map(const key_compare& __comp, const allocator_type& __a)
+        : __tree_(__vc(__comp), typename __base::allocator_type(__a)) {}
+
+    template <class _InputIterator>
+    _LIBCPP_INLINE_VISIBILITY
+        map(_InputIterator __f, _InputIterator __l,
+            const key_compare& __comp = key_compare())
+        : __tree_(__vc(__comp))
+        {
+            insert(__f, __l);
+        }
+
+    template <class _InputIterator>
+    _LIBCPP_INLINE_VISIBILITY
+        map(_InputIterator __f, _InputIterator __l,
+            const key_compare& __comp, const allocator_type& __a)
+        : __tree_(__vc(__comp), typename __base::allocator_type(__a))
+        {
+            insert(__f, __l);
+        }
+
+#if _LIBCPP_STD_VER > 11
+    template <class _InputIterator>
+    _LIBCPP_INLINE_VISIBILITY
+    map(_InputIterator __f, _InputIterator __l, const allocator_type& __a)
+        : map(__f, __l, key_compare(), __a) {}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    map(const map& __m)
+        : __tree_(__m.__tree_)
+        {
+            insert(__m.begin(), __m.end());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    map& operator=(const map& __m)
+        {
+#ifndef _LIBCPP_CXX03_LANG
+            __tree_ = __m.__tree_;
+#else
+            if (this != _VSTD::addressof(__m)) {
+                __tree_.clear();
+                __tree_.value_comp() = __m.__tree_.value_comp();
+                __tree_.__copy_assign_alloc(__m.__tree_);
+                insert(__m.begin(), __m.end());
+            }
+#endif
+            return *this;
+        }
+
+#ifndef _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    map(map&& __m)
+        _NOEXCEPT_(is_nothrow_move_constructible<__base>::value)
+        : __tree_(_VSTD::move(__m.__tree_))
+        {
+        }
+
+    map(map&& __m, const allocator_type& __a);
+
+    _LIBCPP_INLINE_VISIBILITY
+    map& operator=(map&& __m)
+        _NOEXCEPT_(is_nothrow_move_assignable<__base>::value)
+        {
+            __tree_ = _VSTD::move(__m.__tree_);
+            return *this;
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    map(initializer_list<value_type> __il, const key_compare& __comp = key_compare())
+        : __tree_(__vc(__comp))
+        {
+            insert(__il.begin(), __il.end());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    map(initializer_list<value_type> __il, const key_compare& __comp, const allocator_type& __a)
+        : __tree_(__vc(__comp), typename __base::allocator_type(__a))
+        {
+            insert(__il.begin(), __il.end());
+        }
+
+#if _LIBCPP_STD_VER > 11
+    _LIBCPP_INLINE_VISIBILITY
+    map(initializer_list<value_type> __il, const allocator_type& __a)
+        : map(__il, key_compare(), __a) {}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    map& operator=(initializer_list<value_type> __il)
+        {
+            __tree_.__assign_unique(__il.begin(), __il.end());
+            return *this;
+        }
+
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit map(const allocator_type& __a)
+        : __tree_(typename __base::allocator_type(__a))
+        {
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    map(const map& __m, const allocator_type& __a)
+        : __tree_(__m.__tree_.value_comp(), typename __base::allocator_type(__a))
+        {
+            insert(__m.begin(), __m.end());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~map() {
+        static_assert(sizeof(__diagnose_non_const_comparator<_Key, _Compare>()), "");
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+          iterator begin() _NOEXCEPT {return __tree_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const _NOEXCEPT {return __tree_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+          iterator end() _NOEXCEPT {return __tree_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end() const _NOEXCEPT {return __tree_.end();}
+
+    _LIBCPP_INLINE_VISIBILITY
+          reverse_iterator rbegin() _NOEXCEPT {return reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rbegin() const _NOEXCEPT
+        {return const_reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+          reverse_iterator rend() _NOEXCEPT
+            {return       reverse_iterator(begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rend() const _NOEXCEPT
+        {return const_reverse_iterator(begin());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin() const _NOEXCEPT {return begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend() const _NOEXCEPT {return end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crbegin() const _NOEXCEPT {return rbegin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crend() const _NOEXCEPT {return rend();}
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool      empty() const _NOEXCEPT {return __tree_.size() == 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT {return __tree_.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT {return __tree_.max_size();}
+
+    mapped_type& operator[](const key_type& __k);
+#ifndef _LIBCPP_CXX03_LANG
+    mapped_type& operator[](key_type&& __k);
+#endif
+
+          mapped_type& at(const key_type& __k);
+    const mapped_type& at(const key_type& __k) const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT {return allocator_type(__tree_.__alloc());}
+    _LIBCPP_INLINE_VISIBILITY
+    key_compare    key_comp()      const {return __tree_.value_comp().key_comp();}
+    _LIBCPP_INLINE_VISIBILITY
+    value_compare  value_comp()    const {return value_compare(__tree_.value_comp().key_comp());}
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class ..._Args>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> emplace(_Args&& ...__args) {
+        return __tree_.__emplace_unique(_VSTD::forward<_Args>(__args)...);
+    }
+
+    template <class ..._Args>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator emplace_hint(const_iterator __p, _Args&& ...__args) {
+        return __tree_.__emplace_hint_unique(__p.__i_, _VSTD::forward<_Args>(__args)...);
+    }
+
+    template <class _Pp,
+              class = typename enable_if<is_constructible<value_type, _Pp>::value>::type>
+        _LIBCPP_INLINE_VISIBILITY
+        pair<iterator, bool> insert(_Pp&& __p)
+            {return __tree_.__insert_unique(_VSTD::forward<_Pp>(__p));}
+
+    template <class _Pp,
+              class = typename enable_if<is_constructible<value_type, _Pp>::value>::type>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator insert(const_iterator __pos, _Pp&& __p)
+            {return __tree_.__insert_unique(__pos.__i_, _VSTD::forward<_Pp>(__p));}
+
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool>
+        insert(const value_type& __v) {return __tree_.__insert_unique(__v);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator
+        insert(const_iterator __p, const value_type& __v)
+            {return __tree_.__insert_unique(__p.__i_, __v);}
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool>
+    insert(value_type&& __v) {return __tree_.__insert_unique(_VSTD::move(__v));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p,  value_type&& __v)
+    {return __tree_.__insert_unique(__p.__i_, _VSTD::move(__v));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void insert(initializer_list<value_type> __il)
+        {insert(__il.begin(), __il.end());}
+#endif
+
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        void insert(_InputIterator __f, _InputIterator __l)
+        {
+            for (const_iterator __e = cend(); __f != __l; ++__f)
+                insert(__e.__i_, *__f);
+        }
+
+#if _LIBCPP_STD_VER > 14
+
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        pair<iterator, bool> try_emplace(const key_type& __k, _Args&&... __args)
+    {
+        return __tree_.__emplace_unique_key_args(__k,
+            _VSTD::piecewise_construct,
+            _VSTD::forward_as_tuple(__k),
+            _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...));
+    }
+
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        pair<iterator, bool> try_emplace(key_type&& __k, _Args&&... __args)
+    {
+        return __tree_.__emplace_unique_key_args(__k,
+            _VSTD::piecewise_construct,
+            _VSTD::forward_as_tuple(_VSTD::move(__k)),
+            _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...));
+    }
+
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator try_emplace(const_iterator __h, const key_type& __k, _Args&&... __args)
+    {
+        return __tree_.__emplace_hint_unique_key_args(__h.__i_, __k,
+            _VSTD::piecewise_construct,
+            _VSTD::forward_as_tuple(__k),
+            _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...)).first;
+    }
+
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator try_emplace(const_iterator __h, key_type&& __k, _Args&&... __args)
+    {
+        return __tree_.__emplace_hint_unique_key_args(__h.__i_, __k,
+            _VSTD::piecewise_construct,
+            _VSTD::forward_as_tuple(_VSTD::move(__k)),
+            _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...)).first;
+    }
+
+    template <class _Vp>
+        _LIBCPP_INLINE_VISIBILITY
+        pair<iterator, bool> insert_or_assign(const key_type& __k, _Vp&& __v)
+    {
+        iterator __p = lower_bound(__k);
+        if ( __p != end() && !key_comp()(__k, __p->first))
+        {
+            __p->second = _VSTD::forward<_Vp>(__v);
+            return _VSTD::make_pair(__p, false);
+        }
+        return _VSTD::make_pair(emplace_hint(__p, __k, _VSTD::forward<_Vp>(__v)), true);
+    }
+
+    template <class _Vp>
+        _LIBCPP_INLINE_VISIBILITY
+        pair<iterator, bool> insert_or_assign(key_type&& __k, _Vp&& __v)
+    {
+        iterator __p = lower_bound(__k);
+        if ( __p != end() && !key_comp()(__k, __p->first))
+        {
+            __p->second = _VSTD::forward<_Vp>(__v);
+            return _VSTD::make_pair(__p, false);
+        }
+        return _VSTD::make_pair(emplace_hint(__p, _VSTD::move(__k), _VSTD::forward<_Vp>(__v)), true);
+    }
+
+    template <class _Vp>
+    _LIBCPP_INLINE_VISIBILITY iterator insert_or_assign(const_iterator __h,
+                                                        const key_type& __k,
+                                                        _Vp&& __v) {
+      auto [__r, __inserted] = __tree_.__emplace_hint_unique_key_args(
+          __h.__i_, __k, __k, _VSTD::forward<_Vp>(__v));
+
+      if (!__inserted)
+        __r->__get_value().second = _VSTD::forward<_Vp>(__v);
+
+      return __r;
+    }
+
+    template <class _Vp>
+    _LIBCPP_INLINE_VISIBILITY iterator insert_or_assign(const_iterator __h,
+                                                        key_type&& __k,
+                                                        _Vp&& __v) {
+      auto [__r, __inserted] = __tree_.__emplace_hint_unique_key_args(
+          __h.__i_, __k, _VSTD::move(__k), _VSTD::forward<_Vp>(__v));
+
+      if (!__inserted)
+        __r->__get_value().second = _VSTD::forward<_Vp>(__v);
+
+      return __r;
+    }
+
+#endif // _LIBCPP_STD_VER > 14
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(const_iterator __p) {return __tree_.erase(__p.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(iterator __p)       {return __tree_.erase(__p.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type erase(const key_type& __k)
+        {return __tree_.__erase_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator  erase(const_iterator __f, const_iterator __l)
+        {return __tree_.erase(__f.__i_, __l.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT {__tree_.clear();}
+
+#if _LIBCPP_STD_VER > 14
+    _LIBCPP_INLINE_VISIBILITY
+    insert_return_type insert(node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to map::insert()");
+        return __tree_.template __node_handle_insert_unique<
+            node_type, insert_return_type>(_VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __hint, node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to map::insert()");
+        return __tree_.template __node_handle_insert_unique<node_type>(
+            __hint.__i_, _VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(key_type const& __key)
+    {
+        return __tree_.template __node_handle_extract<node_type>(__key);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(const_iterator __it)
+    {
+        return __tree_.template __node_handle_extract<node_type>(__it.__i_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(map<key_type, mapped_type, _Compare2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __tree_.__node_handle_merge_unique(__source.__tree_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(map<key_type, mapped_type, _Compare2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __tree_.__node_handle_merge_unique(__source.__tree_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(multimap<key_type, mapped_type, _Compare2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __tree_.__node_handle_merge_unique(__source.__tree_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(multimap<key_type, mapped_type, _Compare2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __tree_.__node_handle_merge_unique(__source.__tree_);
+    }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(map& __m)
+        _NOEXCEPT_(__is_nothrow_swappable<__base>::value)
+        {__tree_.swap(__m.__tree_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator find(const key_type& __k)             {return __tree_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const key_type& __k) const {return __tree_.find(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,iterator>::type
+    find(const _K2& __k)                           {return __tree_.find(__k);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,const_iterator>::type
+    find(const _K2& __k) const                     {return __tree_.find(__k);}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type      count(const key_type& __k) const
+        {return __tree_.__count_unique(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,size_type>::type
+    count(const _K2& __k) const {return __tree_.__count_multi(__k);}
+#endif
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const key_type& __k) const {return find(__k) != end();}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value, bool>::type
+    contains(const _K2& __k) const { return find(__k) != end(); }
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator lower_bound(const key_type& __k)
+        {return __tree_.lower_bound(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator lower_bound(const key_type& __k) const
+        {return __tree_.lower_bound(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,iterator>::type
+    lower_bound(const _K2& __k)       {return __tree_.lower_bound(__k);}
+
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,const_iterator>::type
+    lower_bound(const _K2& __k) const {return __tree_.lower_bound(__k);}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator upper_bound(const key_type& __k)
+        {return __tree_.upper_bound(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator upper_bound(const key_type& __k) const
+        {return __tree_.upper_bound(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,iterator>::type
+    upper_bound(const _K2& __k)       {return __tree_.upper_bound(__k);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,const_iterator>::type
+    upper_bound(const _K2& __k) const {return __tree_.upper_bound(__k);}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator,iterator> equal_range(const key_type& __k)
+        {return __tree_.__equal_range_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    pair<const_iterator,const_iterator> equal_range(const key_type& __k) const
+        {return __tree_.__equal_range_unique(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,pair<iterator,iterator>>::type
+    equal_range(const _K2& __k)       {return __tree_.__equal_range_multi(__k);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,pair<const_iterator,const_iterator>>::type
+    equal_range(const _K2& __k) const {return __tree_.__equal_range_multi(__k);}
+#endif
+
+private:
+    typedef typename __base::__node                    __node;
+    typedef typename __base::__node_allocator          __node_allocator;
+    typedef typename __base::__node_pointer            __node_pointer;
+    typedef typename __base::__node_base_pointer       __node_base_pointer;
+    typedef typename __base::__parent_pointer          __parent_pointer;
+
+    typedef __map_node_destructor<__node_allocator> _Dp;
+    typedef unique_ptr<__node, _Dp> __node_holder;
+
+#ifdef _LIBCPP_CXX03_LANG
+    __node_holder __construct_node_with_key(const key_type& __k);
+#endif
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator, class _Compare = less<__iter_key_type<_InputIterator>>,
+         class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
+         class = enable_if_t<!__is_allocator<_Compare>::value, void>,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>>
+map(_InputIterator, _InputIterator, _Compare = _Compare(), _Allocator = _Allocator())
+  -> map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>, _Compare, _Allocator>;
+
+template<class _Key, class _Tp, class _Compare = less<remove_const_t<_Key>>,
+         class _Allocator = allocator<pair<const _Key, _Tp>>,
+         class = enable_if_t<!__is_allocator<_Compare>::value, void>,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>>
+map(initializer_list<pair<_Key, _Tp>>, _Compare = _Compare(), _Allocator = _Allocator())
+  -> map<remove_const_t<_Key>, _Tp, _Compare, _Allocator>;
+
+template<class _InputIterator, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>>
+map(_InputIterator, _InputIterator, _Allocator)
+  -> map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
+         less<__iter_key_type<_InputIterator>>, _Allocator>;
+
+template<class _Key, class _Tp, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>>
+map(initializer_list<pair<_Key, _Tp>>, _Allocator)
+  -> map<remove_const_t<_Key>, _Tp, less<remove_const_t<_Key>>, _Allocator>;
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+map<_Key, _Tp, _Compare, _Allocator>::map(map&& __m, const allocator_type& __a)
+    : __tree_(_VSTD::move(__m.__tree_), typename __base::allocator_type(__a))
+{
+    if (__a != __m.get_allocator())
+    {
+        const_iterator __e = cend();
+        while (!__m.empty())
+            __tree_.__insert_unique(__e.__i_,
+                    __m.__tree_.remove(__m.begin().__i_)->__value_.__move());
+    }
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+_Tp&
+map<_Key, _Tp, _Compare, _Allocator>::operator[](const key_type& __k)
+{
+    return __tree_.__emplace_unique_key_args(__k,
+        _VSTD::piecewise_construct,
+        _VSTD::forward_as_tuple(__k),
+        _VSTD::forward_as_tuple()).first->__get_value().second;
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+_Tp&
+map<_Key, _Tp, _Compare, _Allocator>::operator[](key_type&& __k)
+{
+    return __tree_.__emplace_unique_key_args(__k,
+        _VSTD::piecewise_construct,
+        _VSTD::forward_as_tuple(_VSTD::move(__k)),
+        _VSTD::forward_as_tuple()).first->__get_value().second;
+}
+
+#else // _LIBCPP_CXX03_LANG
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+typename map<_Key, _Tp, _Compare, _Allocator>::__node_holder
+map<_Key, _Tp, _Compare, _Allocator>::__construct_node_with_key(const key_type& __k)
+{
+    __node_allocator& __na = __tree_.__node_alloc();
+    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
+    __node_traits::construct(__na, _VSTD::addressof(__h->__value_.__get_value().first), __k);
+    __h.get_deleter().__first_constructed = true;
+    __node_traits::construct(__na, _VSTD::addressof(__h->__value_.__get_value().second));
+    __h.get_deleter().__second_constructed = true;
+    return __h;
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+_Tp&
+map<_Key, _Tp, _Compare, _Allocator>::operator[](const key_type& __k)
+{
+    __parent_pointer __parent;
+    __node_base_pointer& __child = __tree_.__find_equal(__parent, __k);
+    __node_pointer __r = static_cast<__node_pointer>(__child);
+    if (__child == nullptr)
+    {
+        __node_holder __h = __construct_node_with_key(__k);
+        __tree_.__insert_node_at(__parent, __child, static_cast<__node_base_pointer>(__h.get()));
+        __r = __h.release();
+    }
+    return __r->__value_.__get_value().second;
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+_Tp&
+map<_Key, _Tp, _Compare, _Allocator>::at(const key_type& __k)
+{
+    __parent_pointer __parent;
+    __node_base_pointer& __child = __tree_.__find_equal(__parent, __k);
+    if (__child == nullptr)
+        __throw_out_of_range("map::at:  key not found");
+    return static_cast<__node_pointer>(__child)->__value_.__get_value().second;
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+const _Tp&
+map<_Key, _Tp, _Compare, _Allocator>::at(const key_type& __k) const
+{
+    __parent_pointer __parent;
+    __node_base_pointer __child = __tree_.__find_equal(__parent, __k);
+    if (__child == nullptr)
+        __throw_out_of_range("map::at:  key not found");
+    return static_cast<__node_pointer>(__child)->__value_.__get_value().second;
+}
+
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const map<_Key, _Tp, _Compare, _Allocator>& __x,
+           const map<_Key, _Tp, _Compare, _Allocator>& __y)
+{
+    return __x.size() == __y.size() && _VSTD::equal(__x.begin(), __x.end(), __y.begin());
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const map<_Key, _Tp, _Compare, _Allocator>& __x,
+           const map<_Key, _Tp, _Compare, _Allocator>& __y)
+{
+    return _VSTD::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const map<_Key, _Tp, _Compare, _Allocator>& __x,
+           const map<_Key, _Tp, _Compare, _Allocator>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const map<_Key, _Tp, _Compare, _Allocator>& __x,
+           const map<_Key, _Tp, _Compare, _Allocator>& __y)
+{
+    return __y < __x;
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const map<_Key, _Tp, _Compare, _Allocator>& __x,
+           const map<_Key, _Tp, _Compare, _Allocator>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const map<_Key, _Tp, _Compare, _Allocator>& __x,
+           const map<_Key, _Tp, _Compare, _Allocator>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(map<_Key, _Tp, _Compare, _Allocator>& __x,
+     map<_Key, _Tp, _Compare, _Allocator>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Key, class _Tp, class _Compare, class _Allocator,
+          class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+    typename map<_Key, _Tp, _Compare, _Allocator>::size_type
+    erase_if(map<_Key, _Tp, _Compare, _Allocator>& __c, _Predicate __pred) {
+  return _VSTD::__libcpp_erase_if_container(__c, __pred);
+}
+#endif
+
+
+template <class _Key, class _Tp, class _Compare = less<_Key>,
+          class _Allocator = allocator<pair<const _Key, _Tp> > >
+class _LIBCPP_TEMPLATE_VIS multimap
+{
+public:
+    // types:
+    typedef _Key                                     key_type;
+    typedef _Tp                                      mapped_type;
+    typedef pair<const key_type, mapped_type>        value_type;
+    typedef __identity_t<_Compare>                   key_compare;
+    typedef __identity_t<_Allocator>                 allocator_type;
+    typedef value_type&                              reference;
+    typedef const value_type&                        const_reference;
+
+    static_assert((is_same<typename allocator_type::value_type, value_type>::value),
+                  "Allocator::value_type must be same type as value_type");
+
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+    class _LIBCPP_TEMPLATE_VIS value_compare
+#if defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+        : public binary_function<value_type, value_type, bool>
+#endif
+    {
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+        friend class multimap;
+    protected:
+        key_compare comp;
+
+        _LIBCPP_INLINE_VISIBILITY
+        value_compare(key_compare c) : comp(c) {}
+    public:
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+        _LIBCPP_DEPRECATED_IN_CXX17 typedef bool result_type;
+        _LIBCPP_DEPRECATED_IN_CXX17 typedef value_type first_argument_type;
+        _LIBCPP_DEPRECATED_IN_CXX17 typedef value_type second_argument_type;
+#endif
+        _LIBCPP_INLINE_VISIBILITY
+        bool operator()(const value_type& __x, const value_type& __y) const
+            {return comp(__x.first, __y.first);}
+    };
+
+private:
+
+    typedef _VSTD::__value_type<key_type, mapped_type>             __value_type;
+    typedef __map_value_compare<key_type, __value_type, key_compare> __vc;
+    typedef typename __rebind_alloc_helper<allocator_traits<allocator_type>,
+                                                 __value_type>::type __allocator_type;
+    typedef __tree<__value_type, __vc, __allocator_type>            __base;
+    typedef typename __base::__node_traits                          __node_traits;
+    typedef allocator_traits<allocator_type>                        __alloc_traits;
+
+    __base __tree_;
+
+public:
+    typedef typename __alloc_traits::pointer               pointer;
+    typedef typename __alloc_traits::const_pointer         const_pointer;
+    typedef typename __alloc_traits::size_type             size_type;
+    typedef typename __alloc_traits::difference_type       difference_type;
+    typedef __map_iterator<typename __base::iterator>      iterator;
+    typedef __map_const_iterator<typename __base::const_iterator> const_iterator;
+    typedef _VSTD::reverse_iterator<iterator>               reverse_iterator;
+    typedef _VSTD::reverse_iterator<const_iterator>         const_reverse_iterator;
+
+#if _LIBCPP_STD_VER > 14
+    typedef __map_node_handle<typename __base::__node, allocator_type> node_type;
+#endif
+
+    template <class _Key2, class _Value2, class _Comp2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS map;
+    template <class _Key2, class _Value2, class _Comp2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS multimap;
+
+    _LIBCPP_INLINE_VISIBILITY
+    multimap()
+        _NOEXCEPT_(
+            is_nothrow_default_constructible<allocator_type>::value &&
+            is_nothrow_default_constructible<key_compare>::value &&
+            is_nothrow_copy_constructible<key_compare>::value)
+        : __tree_(__vc(key_compare())) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit multimap(const key_compare& __comp)
+        _NOEXCEPT_(
+            is_nothrow_default_constructible<allocator_type>::value &&
+            is_nothrow_copy_constructible<key_compare>::value)
+        : __tree_(__vc(__comp)) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit multimap(const key_compare& __comp, const allocator_type& __a)
+        : __tree_(__vc(__comp), typename __base::allocator_type(__a)) {}
+
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        multimap(_InputIterator __f, _InputIterator __l,
+            const key_compare& __comp = key_compare())
+        : __tree_(__vc(__comp))
+        {
+            insert(__f, __l);
+        }
+
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        multimap(_InputIterator __f, _InputIterator __l,
+            const key_compare& __comp, const allocator_type& __a)
+        : __tree_(__vc(__comp), typename __base::allocator_type(__a))
+        {
+            insert(__f, __l);
+        }
+
+#if _LIBCPP_STD_VER > 11
+    template <class _InputIterator>
+    _LIBCPP_INLINE_VISIBILITY
+    multimap(_InputIterator __f, _InputIterator __l, const allocator_type& __a)
+        : multimap(__f, __l, key_compare(), __a) {}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    multimap(const multimap& __m)
+        : __tree_(__m.__tree_.value_comp(),
+          __alloc_traits::select_on_container_copy_construction(__m.__tree_.__alloc()))
+        {
+            insert(__m.begin(), __m.end());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    multimap& operator=(const multimap& __m)
+        {
+#ifndef _LIBCPP_CXX03_LANG
+            __tree_ = __m.__tree_;
+#else
+            if (this != _VSTD::addressof(__m)) {
+                __tree_.clear();
+                __tree_.value_comp() = __m.__tree_.value_comp();
+                __tree_.__copy_assign_alloc(__m.__tree_);
+                insert(__m.begin(), __m.end());
+            }
+#endif
+            return *this;
+        }
+
+#ifndef _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    multimap(multimap&& __m)
+        _NOEXCEPT_(is_nothrow_move_constructible<__base>::value)
+        : __tree_(_VSTD::move(__m.__tree_))
+        {
+        }
+
+    multimap(multimap&& __m, const allocator_type& __a);
+
+    _LIBCPP_INLINE_VISIBILITY
+    multimap& operator=(multimap&& __m)
+        _NOEXCEPT_(is_nothrow_move_assignable<__base>::value)
+        {
+            __tree_ = _VSTD::move(__m.__tree_);
+            return *this;
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    multimap(initializer_list<value_type> __il, const key_compare& __comp = key_compare())
+        : __tree_(__vc(__comp))
+        {
+            insert(__il.begin(), __il.end());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    multimap(initializer_list<value_type> __il, const key_compare& __comp, const allocator_type& __a)
+        : __tree_(__vc(__comp), typename __base::allocator_type(__a))
+        {
+            insert(__il.begin(), __il.end());
+        }
+
+#if _LIBCPP_STD_VER > 11
+    _LIBCPP_INLINE_VISIBILITY
+    multimap(initializer_list<value_type> __il, const allocator_type& __a)
+        : multimap(__il, key_compare(), __a) {}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    multimap& operator=(initializer_list<value_type> __il)
+        {
+            __tree_.__assign_multi(__il.begin(), __il.end());
+            return *this;
+        }
+
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit multimap(const allocator_type& __a)
+        : __tree_(typename __base::allocator_type(__a))
+        {
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    multimap(const multimap& __m, const allocator_type& __a)
+        : __tree_(__m.__tree_.value_comp(), typename __base::allocator_type(__a))
+        {
+            insert(__m.begin(), __m.end());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~multimap() {
+        static_assert(sizeof(__diagnose_non_const_comparator<_Key, _Compare>()), "");
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+          iterator begin() _NOEXCEPT {return __tree_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const _NOEXCEPT {return __tree_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+          iterator end() _NOEXCEPT {return __tree_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end() const _NOEXCEPT {return __tree_.end();}
+
+    _LIBCPP_INLINE_VISIBILITY
+          reverse_iterator rbegin() _NOEXCEPT {return reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rbegin() const _NOEXCEPT
+        {return const_reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+          reverse_iterator rend() _NOEXCEPT {return reverse_iterator(begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rend() const _NOEXCEPT
+        {return const_reverse_iterator(begin());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin()  const _NOEXCEPT {return begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend() const _NOEXCEPT {return end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crbegin() const _NOEXCEPT {return rbegin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crend() const _NOEXCEPT {return rend();}
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT {return __tree_.size() == 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT {return __tree_.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT {return __tree_.max_size();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT {return allocator_type(__tree_.__alloc());}
+    _LIBCPP_INLINE_VISIBILITY
+    key_compare    key_comp() const {return __tree_.value_comp().key_comp();}
+    _LIBCPP_INLINE_VISIBILITY
+    value_compare  value_comp() const
+        {return value_compare(__tree_.value_comp().key_comp());}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+    template <class ..._Args>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator emplace(_Args&& ...__args) {
+        return __tree_.__emplace_multi(_VSTD::forward<_Args>(__args)...);
+    }
+
+    template <class ..._Args>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator emplace_hint(const_iterator __p, _Args&& ...__args) {
+        return __tree_.__emplace_hint_multi(__p.__i_, _VSTD::forward<_Args>(__args)...);
+    }
+
+    template <class _Pp,
+              class = typename enable_if<is_constructible<value_type, _Pp>::value>::type>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator insert(_Pp&& __p)
+            {return __tree_.__insert_multi(_VSTD::forward<_Pp>(__p));}
+
+    template <class _Pp,
+              class = typename enable_if<is_constructible<value_type, _Pp>::value>::type>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator insert(const_iterator __pos, _Pp&& __p)
+            {return __tree_.__insert_multi(__pos.__i_, _VSTD::forward<_Pp>(__p));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(value_type&& __v)
+        {return __tree_.__insert_multi(_VSTD::move(__v));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, value_type&& __v)
+        {return __tree_.__insert_multi(__p.__i_, _VSTD::move(__v));}
+
+
+    _LIBCPP_INLINE_VISIBILITY
+    void insert(initializer_list<value_type> __il)
+        {insert(__il.begin(), __il.end());}
+
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const value_type& __v) {return __tree_.__insert_multi(__v);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, const value_type& __v)
+            {return __tree_.__insert_multi(__p.__i_, __v);}
+
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        void insert(_InputIterator __f, _InputIterator __l)
+        {
+            for (const_iterator __e = cend(); __f != __l; ++__f)
+                __tree_.__insert_multi(__e.__i_, *__f);
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(const_iterator __p) {return __tree_.erase(__p.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(iterator __p)       {return __tree_.erase(__p.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type erase(const key_type& __k) {return __tree_.__erase_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator  erase(const_iterator __f, const_iterator __l)
+        {return __tree_.erase(__f.__i_, __l.__i_);}
+
+#if _LIBCPP_STD_VER > 14
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to multimap::insert()");
+        return __tree_.template __node_handle_insert_multi<node_type>(
+            _VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __hint, node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to multimap::insert()");
+        return __tree_.template __node_handle_insert_multi<node_type>(
+            __hint.__i_, _VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(key_type const& __key)
+    {
+        return __tree_.template __node_handle_extract<node_type>(__key);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(const_iterator __it)
+    {
+        return __tree_.template __node_handle_extract<node_type>(
+            __it.__i_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(multimap<key_type, mapped_type, _Compare2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __tree_.__node_handle_merge_multi(__source.__tree_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(multimap<key_type, mapped_type, _Compare2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __tree_.__node_handle_merge_multi(__source.__tree_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(map<key_type, mapped_type, _Compare2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __tree_.__node_handle_merge_multi(__source.__tree_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(map<key_type, mapped_type, _Compare2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __tree_.__node_handle_merge_multi(__source.__tree_);
+    }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT {__tree_.clear();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(multimap& __m)
+        _NOEXCEPT_(__is_nothrow_swappable<__base>::value)
+        {__tree_.swap(__m.__tree_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator find(const key_type& __k)             {return __tree_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const key_type& __k) const {return __tree_.find(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,iterator>::type
+    find(const _K2& __k)                           {return __tree_.find(__k);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,const_iterator>::type
+    find(const _K2& __k) const                     {return __tree_.find(__k);}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type      count(const key_type& __k) const
+        {return __tree_.__count_multi(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,size_type>::type
+    count(const _K2& __k) const {return __tree_.__count_multi(__k);}
+#endif
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const key_type& __k) const {return find(__k) != end();}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value, bool>::type
+    contains(const _K2& __k) const { return find(__k) != end(); }
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator lower_bound(const key_type& __k)
+        {return __tree_.lower_bound(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator lower_bound(const key_type& __k) const
+            {return __tree_.lower_bound(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,iterator>::type
+    lower_bound(const _K2& __k)       {return __tree_.lower_bound(__k);}
+
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,const_iterator>::type
+    lower_bound(const _K2& __k) const {return __tree_.lower_bound(__k);}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator upper_bound(const key_type& __k)
+            {return __tree_.upper_bound(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator upper_bound(const key_type& __k) const
+            {return __tree_.upper_bound(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,iterator>::type
+    upper_bound(const _K2& __k)       {return __tree_.upper_bound(__k);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,const_iterator>::type
+    upper_bound(const _K2& __k) const {return __tree_.upper_bound(__k);}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator,iterator>             equal_range(const key_type& __k)
+            {return __tree_.__equal_range_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    pair<const_iterator,const_iterator> equal_range(const key_type& __k) const
+            {return __tree_.__equal_range_multi(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,pair<iterator,iterator>>::type
+    equal_range(const _K2& __k)       {return __tree_.__equal_range_multi(__k);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,pair<const_iterator,const_iterator>>::type
+    equal_range(const _K2& __k) const {return __tree_.__equal_range_multi(__k);}
+#endif
+
+private:
+    typedef typename __base::__node                    __node;
+    typedef typename __base::__node_allocator          __node_allocator;
+    typedef typename __base::__node_pointer            __node_pointer;
+
+    typedef __map_node_destructor<__node_allocator> _Dp;
+    typedef unique_ptr<__node, _Dp> __node_holder;
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator, class _Compare = less<__iter_key_type<_InputIterator>>,
+         class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
+         class = enable_if_t<!__is_allocator<_Compare>::value, void>,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>>
+multimap(_InputIterator, _InputIterator, _Compare = _Compare(), _Allocator = _Allocator())
+  -> multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>, _Compare, _Allocator>;
+
+template<class _Key, class _Tp, class _Compare = less<remove_const_t<_Key>>,
+         class _Allocator = allocator<pair<const _Key, _Tp>>,
+         class = enable_if_t<!__is_allocator<_Compare>::value, void>,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>>
+multimap(initializer_list<pair<_Key, _Tp>>, _Compare = _Compare(), _Allocator = _Allocator())
+  -> multimap<remove_const_t<_Key>, _Tp, _Compare, _Allocator>;
+
+template<class _InputIterator, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>>
+multimap(_InputIterator, _InputIterator, _Allocator)
+  -> multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
+         less<__iter_key_type<_InputIterator>>, _Allocator>;
+
+template<class _Key, class _Tp, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>>
+multimap(initializer_list<pair<_Key, _Tp>>, _Allocator)
+  -> multimap<remove_const_t<_Key>, _Tp, less<remove_const_t<_Key>>, _Allocator>;
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+multimap<_Key, _Tp, _Compare, _Allocator>::multimap(multimap&& __m, const allocator_type& __a)
+    : __tree_(_VSTD::move(__m.__tree_), typename __base::allocator_type(__a))
+{
+    if (__a != __m.get_allocator())
+    {
+        const_iterator __e = cend();
+        while (!__m.empty())
+            __tree_.__insert_multi(__e.__i_,
+                    _VSTD::move(__m.__tree_.remove(__m.begin().__i_)->__value_.__move()));
+    }
+}
+#endif
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const multimap<_Key, _Tp, _Compare, _Allocator>& __x,
+           const multimap<_Key, _Tp, _Compare, _Allocator>& __y)
+{
+    return __x.size() == __y.size() && _VSTD::equal(__x.begin(), __x.end(), __y.begin());
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const multimap<_Key, _Tp, _Compare, _Allocator>& __x,
+           const multimap<_Key, _Tp, _Compare, _Allocator>& __y)
+{
+    return _VSTD::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const multimap<_Key, _Tp, _Compare, _Allocator>& __x,
+           const multimap<_Key, _Tp, _Compare, _Allocator>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const multimap<_Key, _Tp, _Compare, _Allocator>& __x,
+           const multimap<_Key, _Tp, _Compare, _Allocator>& __y)
+{
+    return __y < __x;
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const multimap<_Key, _Tp, _Compare, _Allocator>& __x,
+           const multimap<_Key, _Tp, _Compare, _Allocator>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const multimap<_Key, _Tp, _Compare, _Allocator>& __x,
+           const multimap<_Key, _Tp, _Compare, _Allocator>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _Key, class _Tp, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(multimap<_Key, _Tp, _Compare, _Allocator>& __x,
+     multimap<_Key, _Tp, _Compare, _Allocator>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Key, class _Tp, class _Compare, class _Allocator,
+          class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+    typename multimap<_Key, _Tp, _Compare, _Allocator>::size_type
+    erase_if(multimap<_Key, _Tp, _Compare, _Allocator>& __c,
+             _Predicate __pred) {
+  return _VSTD::__libcpp_erase_if_container(__c, __pred);
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_MAP
diff --git a/contrib/libs/cxxsupp/libcxx/include/math.h b/contrib/libs/cxxsupp/libcxx/include/math.h
new file mode 100644
index 00000000000..9ab54031df5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/math.h
@@ -0,0 +1,1771 @@
+// -*- C++ -*-
+//===---------------------------- math.h ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_MATH_H
+#define _LIBCPP_MATH_H
+
+/*
+    math.h synopsis
+
+Macros:
+
+    HUGE_VAL
+    HUGE_VALF               // C99
+    HUGE_VALL               // C99
+    INFINITY                // C99
+    NAN                     // C99
+    FP_INFINITE             // C99
+    FP_NAN                  // C99
+    FP_NORMAL               // C99
+    FP_SUBNORMAL            // C99
+    FP_ZERO                 // C99
+    FP_FAST_FMA             // C99
+    FP_FAST_FMAF            // C99
+    FP_FAST_FMAL            // C99
+    FP_ILOGB0               // C99
+    FP_ILOGBNAN             // C99
+    MATH_ERRNO              // C99
+    MATH_ERREXCEPT          // C99
+    math_errhandling        // C99
+
+Types:
+
+    float_t                 // C99
+    double_t                // C99
+
+// C90
+
+floating_point abs(floating_point x);
+
+floating_point acos (arithmetic x);
+float          acosf(float x);
+long double    acosl(long double x);
+
+floating_point asin (arithmetic x);
+float          asinf(float x);
+long double    asinl(long double x);
+
+floating_point atan (arithmetic x);
+float          atanf(float x);
+long double    atanl(long double x);
+
+floating_point atan2 (arithmetic y, arithmetic x);
+float          atan2f(float y, float x);
+long double    atan2l(long double y, long double x);
+
+floating_point ceil (arithmetic x);
+float          ceilf(float x);
+long double    ceill(long double x);
+
+floating_point cos (arithmetic x);
+float          cosf(float x);
+long double    cosl(long double x);
+
+floating_point cosh (arithmetic x);
+float          coshf(float x);
+long double    coshl(long double x);
+
+floating_point exp (arithmetic x);
+float          expf(float x);
+long double    expl(long double x);
+
+floating_point fabs (arithmetic x);
+float          fabsf(float x);
+long double    fabsl(long double x);
+
+floating_point floor (arithmetic x);
+float          floorf(float x);
+long double    floorl(long double x);
+
+floating_point fmod (arithmetic x, arithmetic y);
+float          fmodf(float x, float y);
+long double    fmodl(long double x, long double y);
+
+floating_point frexp (arithmetic value, int* exp);
+float          frexpf(float value, int* exp);
+long double    frexpl(long double value, int* exp);
+
+floating_point ldexp (arithmetic value, int exp);
+float          ldexpf(float value, int exp);
+long double    ldexpl(long double value, int exp);
+
+floating_point log (arithmetic x);
+float          logf(float x);
+long double    logl(long double x);
+
+floating_point log10 (arithmetic x);
+float          log10f(float x);
+long double    log10l(long double x);
+
+floating_point modf (floating_point value, floating_point* iptr);
+float          modff(float value, float* iptr);
+long double    modfl(long double value, long double* iptr);
+
+floating_point pow (arithmetic x, arithmetic y);
+float          powf(float x, float y);
+long double    powl(long double x, long double y);
+
+floating_point sin (arithmetic x);
+float          sinf(float x);
+long double    sinl(long double x);
+
+floating_point sinh (arithmetic x);
+float          sinhf(float x);
+long double    sinhl(long double x);
+
+floating_point sqrt (arithmetic x);
+float          sqrtf(float x);
+long double    sqrtl(long double x);
+
+floating_point tan (arithmetic x);
+float          tanf(float x);
+long double    tanl(long double x);
+
+floating_point tanh (arithmetic x);
+float          tanhf(float x);
+long double    tanhl(long double x);
+
+//  C99
+
+bool signbit(arithmetic x);
+
+int fpclassify(arithmetic x);
+
+bool isfinite(arithmetic x);
+bool isinf(arithmetic x);
+bool isnan(arithmetic x);
+bool isnormal(arithmetic x);
+
+bool isgreater(arithmetic x, arithmetic y);
+bool isgreaterequal(arithmetic x, arithmetic y);
+bool isless(arithmetic x, arithmetic y);
+bool islessequal(arithmetic x, arithmetic y);
+bool islessgreater(arithmetic x, arithmetic y);
+bool isunordered(arithmetic x, arithmetic y);
+
+floating_point acosh (arithmetic x);
+float          acoshf(float x);
+long double    acoshl(long double x);
+
+floating_point asinh (arithmetic x);
+float          asinhf(float x);
+long double    asinhl(long double x);
+
+floating_point atanh (arithmetic x);
+float          atanhf(float x);
+long double    atanhl(long double x);
+
+floating_point cbrt (arithmetic x);
+float          cbrtf(float x);
+long double    cbrtl(long double x);
+
+floating_point copysign (arithmetic x, arithmetic y);
+float          copysignf(float x, float y);
+long double    copysignl(long double x, long double y);
+
+floating_point erf (arithmetic x);
+float          erff(float x);
+long double    erfl(long double x);
+
+floating_point erfc (arithmetic x);
+float          erfcf(float x);
+long double    erfcl(long double x);
+
+floating_point exp2 (arithmetic x);
+float          exp2f(float x);
+long double    exp2l(long double x);
+
+floating_point expm1 (arithmetic x);
+float          expm1f(float x);
+long double    expm1l(long double x);
+
+floating_point fdim (arithmetic x, arithmetic y);
+float          fdimf(float x, float y);
+long double    fdiml(long double x, long double y);
+
+floating_point fma (arithmetic x, arithmetic y, arithmetic z);
+float          fmaf(float x, float y, float z);
+long double    fmal(long double x, long double y, long double z);
+
+floating_point fmax (arithmetic x, arithmetic y);
+float          fmaxf(float x, float y);
+long double    fmaxl(long double x, long double y);
+
+floating_point fmin (arithmetic x, arithmetic y);
+float          fminf(float x, float y);
+long double    fminl(long double x, long double y);
+
+floating_point hypot (arithmetic x, arithmetic y);
+float          hypotf(float x, float y);
+long double    hypotl(long double x, long double y);
+
+int ilogb (arithmetic x);
+int ilogbf(float x);
+int ilogbl(long double x);
+
+floating_point lgamma (arithmetic x);
+float          lgammaf(float x);
+long double    lgammal(long double x);
+
+long long llrint (arithmetic x);
+long long llrintf(float x);
+long long llrintl(long double x);
+
+long long llround (arithmetic x);
+long long llroundf(float x);
+long long llroundl(long double x);
+
+floating_point log1p (arithmetic x);
+float          log1pf(float x);
+long double    log1pl(long double x);
+
+floating_point log2 (arithmetic x);
+float          log2f(float x);
+long double    log2l(long double x);
+
+floating_point logb (arithmetic x);
+float          logbf(float x);
+long double    logbl(long double x);
+
+long lrint (arithmetic x);
+long lrintf(float x);
+long lrintl(long double x);
+
+long lround (arithmetic x);
+long lroundf(float x);
+long lroundl(long double x);
+
+double      nan (const char* str);
+float       nanf(const char* str);
+long double nanl(const char* str);
+
+floating_point nearbyint (arithmetic x);
+float          nearbyintf(float x);
+long double    nearbyintl(long double x);
+
+floating_point nextafter (arithmetic x, arithmetic y);
+float          nextafterf(float x, float y);
+long double    nextafterl(long double x, long double y);
+
+floating_point nexttoward (arithmetic x, long double y);
+float          nexttowardf(float x, long double y);
+long double    nexttowardl(long double x, long double y);
+
+floating_point remainder (arithmetic x, arithmetic y);
+float          remainderf(float x, float y);
+long double    remainderl(long double x, long double y);
+
+floating_point remquo (arithmetic x, arithmetic y, int* pquo);
+float          remquof(float x, float y, int* pquo);
+long double    remquol(long double x, long double y, int* pquo);
+
+floating_point rint (arithmetic x);
+float          rintf(float x);
+long double    rintl(long double x);
+
+floating_point round (arithmetic x);
+float          roundf(float x);
+long double    roundl(long double x);
+
+floating_point scalbln (arithmetic x, long ex);
+float          scalblnf(float x, long ex);
+long double    scalblnl(long double x, long ex);
+
+floating_point scalbn (arithmetic x, int ex);
+float          scalbnf(float x, int ex);
+long double    scalbnl(long double x, int ex);
+
+floating_point tgamma (arithmetic x);
+float          tgammaf(float x);
+long double    tgammal(long double x);
+
+floating_point trunc (arithmetic x);
+float          truncf(float x);
+long double    truncl(long double x);
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(math.h)
+#else
+#include_next <math.h>
+#endif
+
+#ifdef __cplusplus
+
+// We support including .h headers inside 'extern "C"' contexts, so switch
+// back to C++ linkage before including these C++ headers.
+extern "C++" {
+
+#include <stdlib.h>
+#include <type_traits>
+#include <limits>
+
+// signbit
+
+#ifdef signbit
+
+template <class _A1>
+_LIBCPP_INLINE_VISIBILITY
+bool
+__libcpp_signbit(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_signbit)
+    return __builtin_signbit(__lcpp_x);
+#else
+    return signbit(__lcpp_x);
+#endif
+}
+
+#undef signbit
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_floating_point<_A1>::value, bool>::type
+signbit(_A1 __lcpp_x) _NOEXCEPT
+{
+    return __libcpp_signbit((typename std::__promote<_A1>::type)__lcpp_x);
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<
+    std::is_integral<_A1>::value && std::is_signed<_A1>::value, bool>::type
+signbit(_A1 __lcpp_x) _NOEXCEPT
+{ return __lcpp_x < 0; }
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<
+    std::is_integral<_A1>::value && !std::is_signed<_A1>::value, bool>::type
+signbit(_A1) _NOEXCEPT
+{ return false; }
+
+#elif defined(_LIBCPP_MSVCRT)
+
+template <typename _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_floating_point<_A1>::value, bool>::type
+signbit(_A1 __lcpp_x) _NOEXCEPT
+{
+  return ::signbit(static_cast<typename std::__promote<_A1>::type>(__lcpp_x));
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<
+    std::is_integral<_A1>::value && std::is_signed<_A1>::value, bool>::type
+signbit(_A1 __lcpp_x) _NOEXCEPT
+{ return __lcpp_x < 0; }
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<
+    std::is_integral<_A1>::value && !std::is_signed<_A1>::value, bool>::type
+signbit(_A1) _NOEXCEPT
+{ return false; }
+
+#endif // signbit
+
+// fpclassify
+
+#ifdef fpclassify
+
+template <class _A1>
+_LIBCPP_INLINE_VISIBILITY
+int
+__libcpp_fpclassify(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_fpclassify)
+  return __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL, FP_SUBNORMAL,
+                                FP_ZERO, __lcpp_x);
+#else
+    return fpclassify(__lcpp_x);
+#endif
+}
+
+#undef fpclassify
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_floating_point<_A1>::value, int>::type
+fpclassify(_A1 __lcpp_x) _NOEXCEPT
+{
+    return __libcpp_fpclassify((typename std::__promote<_A1>::type)__lcpp_x);
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, int>::type
+fpclassify(_A1 __lcpp_x) _NOEXCEPT
+{ return __lcpp_x == 0 ? FP_ZERO : FP_NORMAL; }
+
+#elif defined(_LIBCPP_MSVCRT)
+
+template <typename _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_floating_point<_A1>::value, bool>::type
+fpclassify(_A1 __lcpp_x) _NOEXCEPT
+{
+  return ::fpclassify(static_cast<typename std::__promote<_A1>::type>(__lcpp_x));
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, int>::type
+fpclassify(_A1 __lcpp_x) _NOEXCEPT
+{ return __lcpp_x == 0 ? FP_ZERO : FP_NORMAL; }
+
+#endif // fpclassify
+
+// isfinite
+
+#ifdef isfinite
+
+template <class _A1>
+_LIBCPP_INLINE_VISIBILITY
+bool
+__libcpp_isfinite(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_isfinite)
+    return __builtin_isfinite(__lcpp_x);
+#else
+    return isfinite(__lcpp_x);
+#endif
+}
+
+#undef isfinite
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<
+    std::is_arithmetic<_A1>::value && std::numeric_limits<_A1>::has_infinity,
+    bool>::type
+isfinite(_A1 __lcpp_x) _NOEXCEPT
+{
+    return __libcpp_isfinite((typename std::__promote<_A1>::type)__lcpp_x);
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<
+    std::is_arithmetic<_A1>::value && !std::numeric_limits<_A1>::has_infinity,
+    bool>::type
+isfinite(_A1) _NOEXCEPT
+{ return true; }
+
+#endif // isfinite
+
+// isinf
+
+#ifdef isinf
+
+template <class _A1>
+_LIBCPP_INLINE_VISIBILITY
+bool
+__libcpp_isinf(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_isinf)
+    return __builtin_isinf(__lcpp_x);
+#else
+    return isinf(__lcpp_x);
+#endif
+}
+
+#undef isinf
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<
+    std::is_arithmetic<_A1>::value && std::numeric_limits<_A1>::has_infinity,
+    bool>::type
+isinf(_A1 __lcpp_x) _NOEXCEPT
+{
+    return __libcpp_isinf((typename std::__promote<_A1>::type)__lcpp_x);
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<
+    std::is_arithmetic<_A1>::value && !std::numeric_limits<_A1>::has_infinity,
+    bool>::type
+isinf(_A1) _NOEXCEPT
+{ return false; }
+
+#if defined(_LIBCPP_PREFERRED_OVERLOAD) && !defined(__CUDACC__)
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+isinf(float __lcpp_x) _NOEXCEPT { return __libcpp_isinf(__lcpp_x); }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+bool
+isinf(double __lcpp_x) _NOEXCEPT { return __libcpp_isinf(__lcpp_x); }
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+isinf(long double __lcpp_x) _NOEXCEPT { return __libcpp_isinf(__lcpp_x); }
+#endif
+
+#endif // isinf
+
+// isnan
+
+#ifdef isnan
+
+template <class _A1>
+_LIBCPP_INLINE_VISIBILITY
+bool
+__libcpp_isnan(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_isnan)
+    return __builtin_isnan(__lcpp_x);
+#else
+    return isnan(__lcpp_x);
+#endif
+}
+
+#undef isnan
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_floating_point<_A1>::value, bool>::type
+isnan(_A1 __lcpp_x) _NOEXCEPT
+{
+    return __libcpp_isnan((typename std::__promote<_A1>::type)__lcpp_x);
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, bool>::type
+isnan(_A1) _NOEXCEPT
+{ return false; }
+
+#if defined(_LIBCPP_PREFERRED_OVERLOAD) && !defined(__CUDACC__)
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+isnan(float __lcpp_x) _NOEXCEPT { return __libcpp_isnan(__lcpp_x); }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+bool
+isnan(double __lcpp_x) _NOEXCEPT { return __libcpp_isnan(__lcpp_x); }
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+isnan(long double __lcpp_x) _NOEXCEPT { return __libcpp_isnan(__lcpp_x); }
+#endif
+
+#endif // isnan
+
+// isnormal
+
+#ifdef isnormal
+
+template <class _A1>
+_LIBCPP_INLINE_VISIBILITY
+bool
+__libcpp_isnormal(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_isnormal)
+    return __builtin_isnormal(__lcpp_x);
+#else
+    return isnormal(__lcpp_x);
+#endif
+}
+
+#undef isnormal
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_floating_point<_A1>::value, bool>::type
+isnormal(_A1 __lcpp_x) _NOEXCEPT
+{
+    return __libcpp_isnormal((typename std::__promote<_A1>::type)__lcpp_x);
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, bool>::type
+isnormal(_A1 __lcpp_x) _NOEXCEPT
+{ return __lcpp_x != 0; }
+
+#endif // isnormal
+
+// isgreater
+
+#ifdef isgreater
+
+template <class _A1, class _A2>
+_LIBCPP_INLINE_VISIBILITY
+bool
+__libcpp_isgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    return isgreater(__lcpp_x, __lcpp_y);
+}
+
+#undef isgreater
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    bool
+>::type
+isgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type type;
+    return __libcpp_isgreater((type)__lcpp_x, (type)__lcpp_y);
+}
+
+#endif // isgreater
+
+// isgreaterequal
+
+#ifdef isgreaterequal
+
+template <class _A1, class _A2>
+_LIBCPP_INLINE_VISIBILITY
+bool
+__libcpp_isgreaterequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    return isgreaterequal(__lcpp_x, __lcpp_y);
+}
+
+#undef isgreaterequal
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    bool
+>::type
+isgreaterequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type type;
+    return __libcpp_isgreaterequal((type)__lcpp_x, (type)__lcpp_y);
+}
+
+#endif // isgreaterequal
+
+// isless
+
+#ifdef isless
+
+template <class _A1, class _A2>
+_LIBCPP_INLINE_VISIBILITY
+bool
+__libcpp_isless(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    return isless(__lcpp_x, __lcpp_y);
+}
+
+#undef isless
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    bool
+>::type
+isless(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type type;
+    return __libcpp_isless((type)__lcpp_x, (type)__lcpp_y);
+}
+
+#endif // isless
+
+// islessequal
+
+#ifdef islessequal
+
+template <class _A1, class _A2>
+_LIBCPP_INLINE_VISIBILITY
+bool
+__libcpp_islessequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    return islessequal(__lcpp_x, __lcpp_y);
+}
+
+#undef islessequal
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    bool
+>::type
+islessequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type type;
+    return __libcpp_islessequal((type)__lcpp_x, (type)__lcpp_y);
+}
+
+#endif // islessequal
+
+// islessgreater
+
+#ifdef islessgreater
+
+template <class _A1, class _A2>
+_LIBCPP_INLINE_VISIBILITY
+bool
+__libcpp_islessgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    return islessgreater(__lcpp_x, __lcpp_y);
+}
+
+#undef islessgreater
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    bool
+>::type
+islessgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type type;
+    return __libcpp_islessgreater((type)__lcpp_x, (type)__lcpp_y);
+}
+
+#endif // islessgreater
+
+// isunordered
+
+#ifdef isunordered
+
+template <class _A1, class _A2>
+_LIBCPP_INLINE_VISIBILITY
+bool
+__libcpp_isunordered(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    return isunordered(__lcpp_x, __lcpp_y);
+}
+
+#undef isunordered
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    bool
+>::type
+isunordered(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type type;
+    return __libcpp_isunordered((type)__lcpp_x, (type)__lcpp_y);
+}
+
+#endif // isunordered
+
+// abs
+//
+// handled in stdlib.h
+
+// div
+//
+// handled in stdlib.h
+
+// acos
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       acos(float __lcpp_x) _NOEXCEPT       {return ::acosf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double acos(long double __lcpp_x) _NOEXCEPT {return ::acosl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+acos(_A1 __lcpp_x) _NOEXCEPT {return ::acos((double)__lcpp_x);}
+
+// asin
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       asin(float __lcpp_x) _NOEXCEPT       {return ::asinf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double asin(long double __lcpp_x) _NOEXCEPT {return ::asinl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+asin(_A1 __lcpp_x) _NOEXCEPT {return ::asin((double)__lcpp_x);}
+
+// atan
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       atan(float __lcpp_x) _NOEXCEPT       {return ::atanf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double atan(long double __lcpp_x) _NOEXCEPT {return ::atanl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+atan(_A1 __lcpp_x) _NOEXCEPT {return ::atan((double)__lcpp_x);}
+
+// atan2
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       atan2(float __lcpp_y, float __lcpp_x) _NOEXCEPT             {return ::atan2f(__lcpp_y, __lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double atan2(long double __lcpp_y, long double __lcpp_x) _NOEXCEPT {return ::atan2l(__lcpp_y, __lcpp_x);}
+#endif
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::__enable_if_t
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    std::__promote<_A1, _A2>
+>::type
+atan2(_A1 __lcpp_y, _A2 __lcpp_x) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type __result_type;
+    static_assert((!(std::_IsSame<_A1, __result_type>::value &&
+                     std::_IsSame<_A2, __result_type>::value)), "");
+    return ::atan2((__result_type)__lcpp_y, (__result_type)__lcpp_x);
+}
+
+// ceil
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       ceil(float __lcpp_x) _NOEXCEPT       {return ::ceilf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double ceil(long double __lcpp_x) _NOEXCEPT {return ::ceill(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+ceil(_A1 __lcpp_x) _NOEXCEPT {return ::ceil((double)__lcpp_x);}
+
+// cos
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       cos(float __lcpp_x) _NOEXCEPT       {return ::cosf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double cos(long double __lcpp_x) _NOEXCEPT {return ::cosl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+cos(_A1 __lcpp_x) _NOEXCEPT {return ::cos((double)__lcpp_x);}
+
+// cosh
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       cosh(float __lcpp_x) _NOEXCEPT       {return ::coshf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double cosh(long double __lcpp_x) _NOEXCEPT {return ::coshl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+cosh(_A1 __lcpp_x) _NOEXCEPT {return ::cosh((double)__lcpp_x);}
+
+// exp
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       exp(float __lcpp_x) _NOEXCEPT       {return ::expf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double exp(long double __lcpp_x) _NOEXCEPT {return ::expl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+exp(_A1 __lcpp_x) _NOEXCEPT {return ::exp((double)__lcpp_x);}
+
+// fabs
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       fabs(float __lcpp_x) _NOEXCEPT       {return ::fabsf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double fabs(long double __lcpp_x) _NOEXCEPT {return ::fabsl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+fabs(_A1 __lcpp_x) _NOEXCEPT {return ::fabs((double)__lcpp_x);}
+
+// floor
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       floor(float __lcpp_x) _NOEXCEPT       {return ::floorf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double floor(long double __lcpp_x) _NOEXCEPT {return ::floorl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+floor(_A1 __lcpp_x) _NOEXCEPT {return ::floor((double)__lcpp_x);}
+
+// fmod
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       fmod(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::fmodf(__lcpp_x, __lcpp_y);}
+inline _LIBCPP_INLINE_VISIBILITY long double fmod(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::fmodl(__lcpp_x, __lcpp_y);}
+#endif
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::__enable_if_t
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    std::__promote<_A1, _A2>
+>::type
+fmod(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type __result_type;
+    static_assert((!(std::_IsSame<_A1, __result_type>::value &&
+                     std::_IsSame<_A2, __result_type>::value)), "");
+    return ::fmod((__result_type)__lcpp_x, (__result_type)__lcpp_y);
+}
+
+// frexp
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       frexp(float __lcpp_x, int* __lcpp_e) _NOEXCEPT       {return ::frexpf(__lcpp_x, __lcpp_e);}
+inline _LIBCPP_INLINE_VISIBILITY long double frexp(long double __lcpp_x, int* __lcpp_e) _NOEXCEPT {return ::frexpl(__lcpp_x, __lcpp_e);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+frexp(_A1 __lcpp_x, int* __lcpp_e) _NOEXCEPT {return ::frexp((double)__lcpp_x, __lcpp_e);}
+
+// ldexp
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       ldexp(float __lcpp_x, int __lcpp_e) _NOEXCEPT       {return ::ldexpf(__lcpp_x, __lcpp_e);}
+inline _LIBCPP_INLINE_VISIBILITY long double ldexp(long double __lcpp_x, int __lcpp_e) _NOEXCEPT {return ::ldexpl(__lcpp_x, __lcpp_e);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+ldexp(_A1 __lcpp_x, int __lcpp_e) _NOEXCEPT {return ::ldexp((double)__lcpp_x, __lcpp_e);}
+
+// log
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       log(float __lcpp_x) _NOEXCEPT       {return ::logf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double log(long double __lcpp_x) _NOEXCEPT {return ::logl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+log(_A1 __lcpp_x) _NOEXCEPT {return ::log((double)__lcpp_x);}
+
+// log10
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       log10(float __lcpp_x) _NOEXCEPT       {return ::log10f(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double log10(long double __lcpp_x) _NOEXCEPT {return ::log10l(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+log10(_A1 __lcpp_x) _NOEXCEPT {return ::log10((double)__lcpp_x);}
+
+// modf
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       modf(float __lcpp_x, float* __lcpp_y) _NOEXCEPT             {return ::modff(__lcpp_x, __lcpp_y);}
+inline _LIBCPP_INLINE_VISIBILITY long double modf(long double __lcpp_x, long double* __lcpp_y) _NOEXCEPT {return ::modfl(__lcpp_x, __lcpp_y);}
+#endif
+
+// pow
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       pow(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::powf(__lcpp_x, __lcpp_y);}
+inline _LIBCPP_INLINE_VISIBILITY long double pow(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::powl(__lcpp_x, __lcpp_y);}
+#endif
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::__enable_if_t
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    std::__promote<_A1, _A2>
+>::type
+pow(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type __result_type;
+    static_assert((!(std::_IsSame<_A1, __result_type>::value &&
+                     std::_IsSame<_A2, __result_type>::value)), "");
+    return ::pow((__result_type)__lcpp_x, (__result_type)__lcpp_y);
+}
+
+// sin
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       sin(float __lcpp_x) _NOEXCEPT       {return ::sinf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double sin(long double __lcpp_x) _NOEXCEPT {return ::sinl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+sin(_A1 __lcpp_x) _NOEXCEPT {return ::sin((double)__lcpp_x);}
+
+// sinh
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       sinh(float __lcpp_x) _NOEXCEPT       {return ::sinhf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double sinh(long double __lcpp_x) _NOEXCEPT {return ::sinhl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+sinh(_A1 __lcpp_x) _NOEXCEPT {return ::sinh((double)__lcpp_x);}
+
+// sqrt
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       sqrt(float __lcpp_x) _NOEXCEPT       {return ::sqrtf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double sqrt(long double __lcpp_x) _NOEXCEPT {return ::sqrtl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+sqrt(_A1 __lcpp_x) _NOEXCEPT {return ::sqrt((double)__lcpp_x);}
+
+// tan
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       tan(float __lcpp_x) _NOEXCEPT       {return ::tanf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double tan(long double __lcpp_x) _NOEXCEPT {return ::tanl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+tan(_A1 __lcpp_x) _NOEXCEPT {return ::tan((double)__lcpp_x);}
+
+// tanh
+
+#if !(defined(_AIX) || defined(__sun__))
+inline _LIBCPP_INLINE_VISIBILITY float       tanh(float __lcpp_x) _NOEXCEPT       {return ::tanhf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double tanh(long double __lcpp_x) _NOEXCEPT {return ::tanhl(__lcpp_x);}
+#endif
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+tanh(_A1 __lcpp_x) _NOEXCEPT {return ::tanh((double)__lcpp_x);}
+
+// acosh
+
+inline _LIBCPP_INLINE_VISIBILITY float       acosh(float __lcpp_x) _NOEXCEPT       {return ::acoshf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double acosh(long double __lcpp_x) _NOEXCEPT {return ::acoshl(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+acosh(_A1 __lcpp_x) _NOEXCEPT {return ::acosh((double)__lcpp_x);}
+
+// asinh
+
+inline _LIBCPP_INLINE_VISIBILITY float       asinh(float __lcpp_x) _NOEXCEPT       {return ::asinhf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double asinh(long double __lcpp_x) _NOEXCEPT {return ::asinhl(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+asinh(_A1 __lcpp_x) _NOEXCEPT {return ::asinh((double)__lcpp_x);}
+
+// atanh
+
+inline _LIBCPP_INLINE_VISIBILITY float       atanh(float __lcpp_x) _NOEXCEPT       {return ::atanhf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double atanh(long double __lcpp_x) _NOEXCEPT {return ::atanhl(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+atanh(_A1 __lcpp_x) _NOEXCEPT {return ::atanh((double)__lcpp_x);}
+
+// cbrt
+
+inline _LIBCPP_INLINE_VISIBILITY float       cbrt(float __lcpp_x) _NOEXCEPT       {return ::cbrtf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double cbrt(long double __lcpp_x) _NOEXCEPT {return ::cbrtl(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+cbrt(_A1 __lcpp_x) _NOEXCEPT {return ::cbrt((double)__lcpp_x);}
+
+// copysign
+
+#if __has_builtin(__builtin_copysignf)
+_LIBCPP_CONSTEXPR
+#endif
+inline _LIBCPP_INLINE_VISIBILITY float __libcpp_copysign(float __lcpp_x, float __lcpp_y) _NOEXCEPT {
+#if __has_builtin(__builtin_copysignf)
+  return __builtin_copysignf(__lcpp_x, __lcpp_y);
+#else
+  return ::copysignf(__lcpp_x, __lcpp_y);
+#endif
+}
+
+#if __has_builtin(__builtin_copysign)
+_LIBCPP_CONSTEXPR
+#endif
+inline _LIBCPP_INLINE_VISIBILITY double __libcpp_copysign(double __lcpp_x, double __lcpp_y) _NOEXCEPT {
+#if __has_builtin(__builtin_copysign)
+  return __builtin_copysign(__lcpp_x, __lcpp_y);
+#else
+  return ::copysign(__lcpp_x, __lcpp_y);
+#endif
+}
+
+#if __has_builtin(__builtin_copysignl)
+_LIBCPP_CONSTEXPR
+#endif
+inline _LIBCPP_INLINE_VISIBILITY long double __libcpp_copysign(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {
+#if __has_builtin(__builtin_copysignl)
+  return __builtin_copysignl(__lcpp_x, __lcpp_y);
+#else
+  return ::copysignl(__lcpp_x, __lcpp_y);
+#endif
+}
+
+template <class _A1, class _A2>
+#if __has_builtin(__builtin_copysign)
+_LIBCPP_CONSTEXPR
+#endif
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::__enable_if_t
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    std::__promote<_A1, _A2>
+>::type
+__libcpp_copysign(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT {
+    typedef typename std::__promote<_A1, _A2>::type __result_type;
+    static_assert((!(std::_IsSame<_A1, __result_type>::value &&
+                     std::_IsSame<_A2, __result_type>::value)), "");
+#if __has_builtin(__builtin_copysign)
+    return __builtin_copysign((__result_type)__lcpp_x, (__result_type)__lcpp_y);
+#else
+    return ::copysign((__result_type)__lcpp_x, (__result_type)__lcpp_y);
+#endif
+}
+
+inline _LIBCPP_INLINE_VISIBILITY float copysign(float __lcpp_x, float __lcpp_y) _NOEXCEPT {
+  return ::__libcpp_copysign(__lcpp_x, __lcpp_y);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY long double copysign(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {
+  return ::__libcpp_copysign(__lcpp_x, __lcpp_y);
+}
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::__enable_if_t
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    std::__promote<_A1, _A2>
+>::type
+    copysign(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT {
+  return ::__libcpp_copysign(__lcpp_x, __lcpp_y);
+}
+
+// erf
+
+inline _LIBCPP_INLINE_VISIBILITY float       erf(float __lcpp_x) _NOEXCEPT       {return ::erff(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double erf(long double __lcpp_x) _NOEXCEPT {return ::erfl(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+erf(_A1 __lcpp_x) _NOEXCEPT {return ::erf((double)__lcpp_x);}
+
+// erfc
+
+inline _LIBCPP_INLINE_VISIBILITY float       erfc(float __lcpp_x) _NOEXCEPT       {return ::erfcf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double erfc(long double __lcpp_x) _NOEXCEPT {return ::erfcl(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+erfc(_A1 __lcpp_x) _NOEXCEPT {return ::erfc((double)__lcpp_x);}
+
+// exp2
+
+inline _LIBCPP_INLINE_VISIBILITY float       exp2(float __lcpp_x) _NOEXCEPT       {return ::exp2f(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double exp2(long double __lcpp_x) _NOEXCEPT {return ::exp2l(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+exp2(_A1 __lcpp_x) _NOEXCEPT {return ::exp2((double)__lcpp_x);}
+
+// expm1
+
+inline _LIBCPP_INLINE_VISIBILITY float       expm1(float __lcpp_x) _NOEXCEPT       {return ::expm1f(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double expm1(long double __lcpp_x) _NOEXCEPT {return ::expm1l(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+expm1(_A1 __lcpp_x) _NOEXCEPT {return ::expm1((double)__lcpp_x);}
+
+// fdim
+
+inline _LIBCPP_INLINE_VISIBILITY float       fdim(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::fdimf(__lcpp_x, __lcpp_y);}
+inline _LIBCPP_INLINE_VISIBILITY long double fdim(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::fdiml(__lcpp_x, __lcpp_y);}
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::__enable_if_t
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    std::__promote<_A1, _A2>
+>::type
+fdim(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type __result_type;
+    static_assert((!(std::_IsSame<_A1, __result_type>::value &&
+                     std::_IsSame<_A2, __result_type>::value)), "");
+    return ::fdim((__result_type)__lcpp_x, (__result_type)__lcpp_y);
+}
+
+// fma
+
+inline _LIBCPP_INLINE_VISIBILITY float       fma(float __lcpp_x, float __lcpp_y, float __lcpp_z) _NOEXCEPT
+{
+#if __has_builtin(__builtin_fmaf)
+    return __builtin_fmaf(__lcpp_x, __lcpp_y, __lcpp_z);
+#else
+    return ::fmaf(__lcpp_x, __lcpp_y, __lcpp_z);
+#endif
+}
+inline _LIBCPP_INLINE_VISIBILITY long double fma(long double __lcpp_x, long double __lcpp_y, long double __lcpp_z) _NOEXCEPT
+{
+#if __has_builtin(__builtin_fmal)
+    return __builtin_fmal(__lcpp_x, __lcpp_y, __lcpp_z);
+#else
+    return ::fmal(__lcpp_x, __lcpp_y, __lcpp_z);
+#endif
+}
+
+template <class _A1, class _A2, class _A3>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::__enable_if_t
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value &&
+    std::is_arithmetic<_A3>::value,
+    std::__promote<_A1, _A2, _A3>
+>::type
+fma(_A1 __lcpp_x, _A2 __lcpp_y, _A3 __lcpp_z) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2, _A3>::type __result_type;
+    static_assert((!(std::_IsSame<_A1, __result_type>::value &&
+                     std::_IsSame<_A2, __result_type>::value &&
+                     std::_IsSame<_A3, __result_type>::value)), "");
+#if __has_builtin(__builtin_fma)
+    return __builtin_fma((__result_type)__lcpp_x, (__result_type)__lcpp_y, (__result_type)__lcpp_z);
+#else
+    return ::fma((__result_type)__lcpp_x, (__result_type)__lcpp_y, (__result_type)__lcpp_z);
+#endif
+}
+
+// fmax
+
+inline _LIBCPP_INLINE_VISIBILITY float       fmax(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::fmaxf(__lcpp_x, __lcpp_y);}
+inline _LIBCPP_INLINE_VISIBILITY long double fmax(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::fmaxl(__lcpp_x, __lcpp_y);}
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::__enable_if_t
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    std::__promote<_A1, _A2>
+>::type
+fmax(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type __result_type;
+    static_assert((!(std::_IsSame<_A1, __result_type>::value &&
+                     std::_IsSame<_A2, __result_type>::value)), "");
+    return ::fmax((__result_type)__lcpp_x, (__result_type)__lcpp_y);
+}
+
+// fmin
+
+inline _LIBCPP_INLINE_VISIBILITY float       fmin(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::fminf(__lcpp_x, __lcpp_y);}
+inline _LIBCPP_INLINE_VISIBILITY long double fmin(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::fminl(__lcpp_x, __lcpp_y);}
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::__enable_if_t
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    std::__promote<_A1, _A2>
+>::type
+fmin(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type __result_type;
+    static_assert((!(std::_IsSame<_A1, __result_type>::value &&
+                     std::_IsSame<_A2, __result_type>::value)), "");
+    return ::fmin((__result_type)__lcpp_x, (__result_type)__lcpp_y);
+}
+
+// hypot
+
+inline _LIBCPP_INLINE_VISIBILITY float       hypot(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::hypotf(__lcpp_x, __lcpp_y);}
+inline _LIBCPP_INLINE_VISIBILITY long double hypot(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::hypotl(__lcpp_x, __lcpp_y);}
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::__enable_if_t
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    std::__promote<_A1, _A2>
+>::type
+hypot(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type __result_type;
+    static_assert((!(std::_IsSame<_A1, __result_type>::value &&
+                     std::_IsSame<_A2, __result_type>::value)), "");
+    return ::hypot((__result_type)__lcpp_x, (__result_type)__lcpp_y);
+}
+
+// ilogb
+
+inline _LIBCPP_INLINE_VISIBILITY int ilogb(float __lcpp_x) _NOEXCEPT       {return ::ilogbf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY int ilogb(long double __lcpp_x) _NOEXCEPT {return ::ilogbl(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, int>::type
+ilogb(_A1 __lcpp_x) _NOEXCEPT {return ::ilogb((double)__lcpp_x);}
+
+// lgamma
+
+inline _LIBCPP_INLINE_VISIBILITY float       lgamma(float __lcpp_x) _NOEXCEPT       {return ::lgammaf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double lgamma(long double __lcpp_x) _NOEXCEPT {return ::lgammal(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+lgamma(_A1 __lcpp_x) _NOEXCEPT {return ::lgamma((double)__lcpp_x);}
+
+// llrint
+
+inline _LIBCPP_INLINE_VISIBILITY long long llrint(float __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_llrintf)
+    return __builtin_llrintf(__lcpp_x);
+#else
+    return ::llrintf(__lcpp_x);
+#endif
+}
+inline _LIBCPP_INLINE_VISIBILITY long long llrint(long double __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_llrintl)
+    return __builtin_llrintl(__lcpp_x);
+#else
+    return ::llrintl(__lcpp_x);
+#endif
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, long long>::type
+llrint(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_llrint)
+    return __builtin_llrint((double)__lcpp_x);
+#else
+    return ::llrint((double)__lcpp_x);
+#endif
+}
+
+// llround
+
+inline _LIBCPP_INLINE_VISIBILITY long long llround(float __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_llroundf)
+    return __builtin_llroundf(__lcpp_x);
+#else
+    return ::llroundf(__lcpp_x);
+#endif
+}
+inline _LIBCPP_INLINE_VISIBILITY long long llround(long double __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_llroundl)
+    return __builtin_llroundl(__lcpp_x);
+#else
+    return ::llroundl(__lcpp_x);
+#endif
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, long long>::type
+llround(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_llround)
+    return __builtin_llround((double)__lcpp_x);
+#else
+    return ::llround((double)__lcpp_x);
+#endif
+}
+
+// log1p
+
+inline _LIBCPP_INLINE_VISIBILITY float       log1p(float __lcpp_x) _NOEXCEPT       {return ::log1pf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double log1p(long double __lcpp_x) _NOEXCEPT {return ::log1pl(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+log1p(_A1 __lcpp_x) _NOEXCEPT {return ::log1p((double)__lcpp_x);}
+
+// log2
+
+inline _LIBCPP_INLINE_VISIBILITY float       log2(float __lcpp_x) _NOEXCEPT       {return ::log2f(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double log2(long double __lcpp_x) _NOEXCEPT {return ::log2l(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+log2(_A1 __lcpp_x) _NOEXCEPT {return ::log2((double)__lcpp_x);}
+
+// logb
+
+inline _LIBCPP_INLINE_VISIBILITY float       logb(float __lcpp_x) _NOEXCEPT       {return ::logbf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double logb(long double __lcpp_x) _NOEXCEPT {return ::logbl(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+logb(_A1 __lcpp_x) _NOEXCEPT {return ::logb((double)__lcpp_x);}
+
+// lrint
+
+inline _LIBCPP_INLINE_VISIBILITY long lrint(float __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_lrintf)
+    return __builtin_lrintf(__lcpp_x);
+#else
+    return ::lrintf(__lcpp_x);
+#endif
+}
+inline _LIBCPP_INLINE_VISIBILITY long lrint(long double __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_lrintl)
+    return __builtin_lrintl(__lcpp_x);
+#else
+    return ::lrintl(__lcpp_x);
+#endif
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, long>::type
+lrint(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_lrint)
+    return __builtin_lrint((double)__lcpp_x);
+#else
+    return ::lrint((double)__lcpp_x);
+#endif
+}
+
+// lround
+
+inline _LIBCPP_INLINE_VISIBILITY long lround(float __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_lroundf)
+    return __builtin_lroundf(__lcpp_x);
+#else
+    return ::lroundf(__lcpp_x);
+#endif
+}
+inline _LIBCPP_INLINE_VISIBILITY long lround(long double __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_lroundl)
+    return __builtin_lroundl(__lcpp_x);
+#else
+    return ::lroundl(__lcpp_x);
+#endif
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, long>::type
+lround(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_lround)
+    return __builtin_lround((double)__lcpp_x);
+#else
+    return ::lround((double)__lcpp_x);
+#endif
+}
+
+// nan
+
+// nearbyint
+
+inline _LIBCPP_INLINE_VISIBILITY float       nearbyint(float __lcpp_x) _NOEXCEPT       {return ::nearbyintf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double nearbyint(long double __lcpp_x) _NOEXCEPT {return ::nearbyintl(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+nearbyint(_A1 __lcpp_x) _NOEXCEPT {return ::nearbyint((double)__lcpp_x);}
+
+// nextafter
+
+inline _LIBCPP_INLINE_VISIBILITY float       nextafter(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::nextafterf(__lcpp_x, __lcpp_y);}
+inline _LIBCPP_INLINE_VISIBILITY long double nextafter(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::nextafterl(__lcpp_x, __lcpp_y);}
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::__enable_if_t
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    std::__promote<_A1, _A2>
+>::type
+nextafter(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type __result_type;
+    static_assert((!(std::_IsSame<_A1, __result_type>::value &&
+                     std::_IsSame<_A2, __result_type>::value)), "");
+    return ::nextafter((__result_type)__lcpp_x, (__result_type)__lcpp_y);
+}
+
+// nexttoward
+
+inline _LIBCPP_INLINE_VISIBILITY float       nexttoward(float __lcpp_x, long double __lcpp_y) _NOEXCEPT       {return ::nexttowardf(__lcpp_x, __lcpp_y);}
+inline _LIBCPP_INLINE_VISIBILITY long double nexttoward(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::nexttowardl(__lcpp_x, __lcpp_y);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+nexttoward(_A1 __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::nexttoward((double)__lcpp_x, __lcpp_y);}
+
+// remainder
+
+inline _LIBCPP_INLINE_VISIBILITY float       remainder(float __lcpp_x, float __lcpp_y) _NOEXCEPT             {return ::remainderf(__lcpp_x, __lcpp_y);}
+inline _LIBCPP_INLINE_VISIBILITY long double remainder(long double __lcpp_x, long double __lcpp_y) _NOEXCEPT {return ::remainderl(__lcpp_x, __lcpp_y);}
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::__enable_if_t
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    std::__promote<_A1, _A2>
+>::type
+remainder(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type __result_type;
+    static_assert((!(std::_IsSame<_A1, __result_type>::value &&
+                     std::_IsSame<_A2, __result_type>::value)), "");
+    return ::remainder((__result_type)__lcpp_x, (__result_type)__lcpp_y);
+}
+
+// remquo
+
+inline _LIBCPP_INLINE_VISIBILITY float       remquo(float __lcpp_x, float __lcpp_y, int* __lcpp_z) _NOEXCEPT             {return ::remquof(__lcpp_x, __lcpp_y, __lcpp_z);}
+inline _LIBCPP_INLINE_VISIBILITY long double remquo(long double __lcpp_x, long double __lcpp_y, int* __lcpp_z) _NOEXCEPT {return ::remquol(__lcpp_x, __lcpp_y, __lcpp_z);}
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::__enable_if_t
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    std::__promote<_A1, _A2>
+>::type
+remquo(_A1 __lcpp_x, _A2 __lcpp_y, int* __lcpp_z) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type __result_type;
+    static_assert((!(std::_IsSame<_A1, __result_type>::value &&
+                     std::_IsSame<_A2, __result_type>::value)), "");
+    return ::remquo((__result_type)__lcpp_x, (__result_type)__lcpp_y, __lcpp_z);
+}
+
+// rint
+
+inline _LIBCPP_INLINE_VISIBILITY float       rint(float __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_rintf)
+    return __builtin_rintf(__lcpp_x);
+#else
+    return ::rintf(__lcpp_x);
+#endif
+}
+inline _LIBCPP_INLINE_VISIBILITY long double rint(long double __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_rintl)
+    return __builtin_rintl(__lcpp_x);
+#else
+    return ::rintl(__lcpp_x);
+#endif
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+rint(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_rint)
+    return __builtin_rint((double)__lcpp_x);
+#else
+    return ::rint((double)__lcpp_x);
+#endif
+}
+
+// round
+
+inline _LIBCPP_INLINE_VISIBILITY float       round(float __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_roundf)
+    return __builtin_roundf(__lcpp_x);
+#else
+    return ::roundf(__lcpp_x);
+#endif
+}
+inline _LIBCPP_INLINE_VISIBILITY long double round(long double __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_roundl)
+    return __builtin_roundl(__lcpp_x);
+#else
+    return ::roundl(__lcpp_x);
+#endif
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+round(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_round)
+    return __builtin_round((double)__lcpp_x);
+#else
+    return ::round((double)__lcpp_x);
+#endif
+}
+
+// scalbln
+
+inline _LIBCPP_INLINE_VISIBILITY float       scalbln(float __lcpp_x, long __lcpp_y) _NOEXCEPT       {return ::scalblnf(__lcpp_x, __lcpp_y);}
+inline _LIBCPP_INLINE_VISIBILITY long double scalbln(long double __lcpp_x, long __lcpp_y) _NOEXCEPT {return ::scalblnl(__lcpp_x, __lcpp_y);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+scalbln(_A1 __lcpp_x, long __lcpp_y) _NOEXCEPT {return ::scalbln((double)__lcpp_x, __lcpp_y);}
+
+// scalbn
+
+inline _LIBCPP_INLINE_VISIBILITY float       scalbn(float __lcpp_x, int __lcpp_y) _NOEXCEPT       {return ::scalbnf(__lcpp_x, __lcpp_y);}
+inline _LIBCPP_INLINE_VISIBILITY long double scalbn(long double __lcpp_x, int __lcpp_y) _NOEXCEPT {return ::scalbnl(__lcpp_x, __lcpp_y);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+scalbn(_A1 __lcpp_x, int __lcpp_y) _NOEXCEPT {return ::scalbn((double)__lcpp_x, __lcpp_y);}
+
+// tgamma
+
+inline _LIBCPP_INLINE_VISIBILITY float       tgamma(float __lcpp_x) _NOEXCEPT       {return ::tgammaf(__lcpp_x);}
+inline _LIBCPP_INLINE_VISIBILITY long double tgamma(long double __lcpp_x) _NOEXCEPT {return ::tgammal(__lcpp_x);}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+tgamma(_A1 __lcpp_x) _NOEXCEPT {return ::tgamma((double)__lcpp_x);}
+
+// trunc
+
+inline _LIBCPP_INLINE_VISIBILITY float       trunc(float __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_truncf)
+    return __builtin_truncf(__lcpp_x);
+#else
+    return ::truncf(__lcpp_x);
+#endif
+}
+inline _LIBCPP_INLINE_VISIBILITY long double trunc(long double __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_truncl)
+    return __builtin_truncl(__lcpp_x);
+#else
+    return ::truncl(__lcpp_x);
+#endif
+}
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_integral<_A1>::value, double>::type
+trunc(_A1 __lcpp_x) _NOEXCEPT
+{
+#if __has_builtin(__builtin_trunc)
+    return __builtin_trunc((double)__lcpp_x);
+#else
+    return ::trunc((double)__lcpp_x);
+#endif
+}
+
+} // extern "C++"
+
+#endif // __cplusplus
+
+#else // _LIBCPP_MATH_H
+
+// This include lives outside the header guard in order to support an MSVC
+// extension which allows users to do:
+//
+// #define _USE_MATH_DEFINES
+// #include <math.h>
+//
+// and receive the definitions of mathematical constants, even if <math.h>
+// has previously been included.
+#if defined(_LIBCPP_MSVCRT) && defined(_USE_MATH_DEFINES)
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(math.h)
+#else
+#include_next <math.h>
+#endif
+#endif
+
+#endif // _LIBCPP_MATH_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/memory b/contrib/libs/cxxsupp/libcxx/include/memory
new file mode 100644
index 00000000000..1975092ba0a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/memory
@@ -0,0 +1,964 @@
+// -*- C++ -*-
+//===-------------------------- memory ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_MEMORY
+#define _LIBCPP_MEMORY
+
+/*
+    memory synopsis
+
+namespace std
+{
+
+struct allocator_arg_t { };
+inline constexpr allocator_arg_t allocator_arg = allocator_arg_t();
+
+template <class T, class Alloc> struct uses_allocator;
+
+template <class Ptr>
+struct pointer_traits
+{
+    typedef Ptr pointer;
+    typedef <details> element_type;
+    typedef <details> difference_type;
+
+    template <class U> using rebind = <details>;
+
+    static pointer pointer_to(<details>);
+};
+
+template <class T>
+struct pointer_traits<T*>
+{
+    typedef T* pointer;
+    typedef T element_type;
+    typedef ptrdiff_t difference_type;
+
+    template <class U> using rebind = U*;
+
+    static pointer pointer_to(<details>) noexcept; // constexpr in C++20
+};
+
+template <class T> constexpr T* to_address(T* p) noexcept; // C++20
+template <class Ptr> constexpr auto to_address(const Ptr& p) noexcept; // C++20
+
+template <class Alloc>
+struct allocator_traits
+{
+    typedef Alloc                        allocator_type;
+    typedef typename allocator_type::value_type
+                                         value_type;
+
+    typedef Alloc::pointer | value_type* pointer;
+    typedef Alloc::const_pointer
+          | pointer_traits<pointer>::rebind<const value_type>
+                                         const_pointer;
+    typedef Alloc::void_pointer
+          | pointer_traits<pointer>::rebind<void>
+                                         void_pointer;
+    typedef Alloc::const_void_pointer
+          | pointer_traits<pointer>::rebind<const void>
+                                         const_void_pointer;
+    typedef Alloc::difference_type
+          | pointer_traits<pointer>::difference_type
+                                         difference_type;
+    typedef Alloc::size_type
+          | make_unsigned<difference_type>::type
+                                         size_type;
+    typedef Alloc::propagate_on_container_copy_assignment
+          | false_type                   propagate_on_container_copy_assignment;
+    typedef Alloc::propagate_on_container_move_assignment
+          | false_type                   propagate_on_container_move_assignment;
+    typedef Alloc::propagate_on_container_swap
+          | false_type                   propagate_on_container_swap;
+    typedef Alloc::is_always_equal
+          | is_empty                     is_always_equal;
+
+    template <class T> using rebind_alloc  = Alloc::rebind<T>::other | Alloc<T, Args...>;
+    template <class T> using rebind_traits = allocator_traits<rebind_alloc<T>>;
+
+    static pointer allocate(allocator_type& a, size_type n);                          // constexpr and [[nodiscard]] in C++20
+    static pointer allocate(allocator_type& a, size_type n, const_void_pointer hint); // constexpr and [[nodiscard]] in C++20
+
+    static void deallocate(allocator_type& a, pointer p, size_type n) noexcept; // constexpr in C++20
+
+    template <class T, class... Args>
+    static void construct(allocator_type& a, T* p, Args&&... args); // constexpr in C++20
+
+    template <class T>
+    static void destroy(allocator_type& a, T* p); // constexpr in C++20
+
+    static size_type max_size(const allocator_type& a); // noexcept in C++14, constexpr in C++20
+    static allocator_type select_on_container_copy_construction(const allocator_type& a); // constexpr in C++20
+};
+
+template <>
+class allocator<void> // removed in C++20
+{
+public:
+    typedef void*                                 pointer;
+    typedef const void*                           const_pointer;
+    typedef void                                  value_type;
+
+    template <class _Up> struct rebind {typedef allocator<_Up> other;};
+};
+
+template <class T>
+class allocator
+{
+public:
+    typedef size_t    size_type;
+    typedef ptrdiff_t difference_type;
+    typedef T*        pointer;                           // deprecated in C++17, removed in C++20
+    typedef const T*  const_pointer;                     // deprecated in C++17, removed in C++20
+    typedef typename add_lvalue_reference<T>::type
+                      reference;                         // deprecated in C++17, removed in C++20
+    typedef typename add_lvalue_reference<const T>::type
+                      const_reference;                   // deprecated in C++17, removed in C++20
+
+    typedef T         value_type;
+
+    template <class U> struct rebind {typedef allocator<U> other;}; // deprecated in C++17, removed in C++20
+
+    typedef true_type propagate_on_container_move_assignment;
+    typedef true_type is_always_equal;
+
+    constexpr allocator() noexcept;                      // constexpr in C++20
+    constexpr allocator(const allocator&) noexcept;      // constexpr in C++20
+    template <class U>
+      constexpr allocator(const allocator<U>&) noexcept; // constexpr in C++20
+    ~allocator();                                        // constexpr in C++20
+    pointer address(reference x) const noexcept;             // deprecated in C++17, removed in C++20
+    const_pointer address(const_reference x) const noexcept; // deprecated in C++17, removed in C++20
+    T* allocate(size_t n, const void* hint);          // deprecated in C++17, removed in C++20
+    T* allocate(size_t n);                              // constexpr in C++20
+    void deallocate(T* p, size_t n) noexcept;           // constexpr in C++20
+    size_type max_size() const noexcept;              // deprecated in C++17, removed in C++20
+    template<class U, class... Args>
+        void construct(U* p, Args&&... args);         // deprecated in C++17, removed in C++20
+    template <class U>
+        void destroy(U* p);                           // deprecated in C++17, removed in C++20
+};
+
+template <class T, class U>
+bool operator==(const allocator<T>&, const allocator<U>&) noexcept; // constexpr in C++20
+
+template <class T, class U>
+bool operator!=(const allocator<T>&, const allocator<U>&) noexcept; // constexpr in C++20
+
+template <class OutputIterator, class T>
+class raw_storage_iterator // deprecated in C++17, removed in C++20
+    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
+{
+public:
+    typedef output_iterator_tag iterator_category;
+    typedef void                value_type;
+    typedef void                difference_type; // until C++20
+    typedef ptrdiff_t           difference_type; // since C++20
+    typedef void                pointer;
+    typedef void                reference;
+
+    explicit raw_storage_iterator(OutputIterator x);
+    raw_storage_iterator& operator*();
+    raw_storage_iterator& operator=(const T& element);
+    raw_storage_iterator& operator++();
+    raw_storage_iterator  operator++(int);
+};
+
+template <class T> pair<T*,ptrdiff_t> get_temporary_buffer(ptrdiff_t n) noexcept;
+template <class T> void               return_temporary_buffer(T* p) noexcept;
+
+template <class T> T* addressof(T& r) noexcept;
+template <class T> T* addressof(const T&& r) noexcept = delete;
+
+template <class InputIterator, class ForwardIterator>
+ForwardIterator
+uninitialized_copy(InputIterator first, InputIterator last, ForwardIterator result);
+
+template <class InputIterator, class Size, class ForwardIterator>
+ForwardIterator
+uninitialized_copy_n(InputIterator first, Size n, ForwardIterator result);
+
+template <class ForwardIterator, class T>
+void uninitialized_fill(ForwardIterator first, ForwardIterator last, const T& x);
+
+template <class ForwardIterator, class Size, class T>
+ForwardIterator
+uninitialized_fill_n(ForwardIterator first, Size n, const T& x);
+
+template <class T, class ...Args>
+constexpr T* construct_at(T* location, Args&& ...args); // since C++20
+
+template <class T>
+void destroy_at(T* location); // constexpr in C++20
+
+template <class ForwardIterator>
+void destroy(ForwardIterator first, ForwardIterator last); // constexpr in C++20
+
+template <class ForwardIterator, class Size>
+ForwardIterator destroy_n(ForwardIterator first, Size n); // constexpr in C++20
+
+template <class InputIterator, class ForwardIterator>
+ ForwardIterator uninitialized_move(InputIterator first, InputIterator last, ForwardIterator result);
+
+template <class InputIterator, class Size, class ForwardIterator>
+ pair<InputIterator,ForwardIterator> uninitialized_move_n(InputIterator first, Size n, ForwardIterator result);
+
+template <class ForwardIterator>
+ void uninitialized_value_construct(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class Size>
+ ForwardIterator uninitialized_value_construct_n(ForwardIterator first, Size n);
+
+template <class ForwardIterator>
+ void uninitialized_default_construct(ForwardIterator first, ForwardIterator last);
+
+template <class ForwardIterator, class Size>
+ ForwardIterator uninitialized_default_construct_n(ForwardIterator first, Size n);
+
+template <class Y> struct auto_ptr_ref {};      // deprecated in C++11, removed in C++17
+
+template<class X>
+class auto_ptr                                  // deprecated in C++11, removed in C++17
+{
+public:
+    typedef X element_type;
+
+    explicit auto_ptr(X* p =0) throw();
+    auto_ptr(auto_ptr&) throw();
+    template<class Y> auto_ptr(auto_ptr<Y>&) throw();
+    auto_ptr& operator=(auto_ptr&) throw();
+    template<class Y> auto_ptr& operator=(auto_ptr<Y>&) throw();
+    auto_ptr& operator=(auto_ptr_ref<X> r) throw();
+    ~auto_ptr() throw();
+
+    typename add_lvalue_reference<X>::type operator*() const throw();
+    X* operator->() const throw();
+    X* get() const throw();
+    X* release() throw();
+    void reset(X* p =0) throw();
+
+    auto_ptr(auto_ptr_ref<X>) throw();
+    template<class Y> operator auto_ptr_ref<Y>() throw();
+    template<class Y> operator auto_ptr<Y>() throw();
+};
+
+template <class T>
+struct default_delete
+{
+    constexpr default_delete() noexcept = default;
+    template <class U> default_delete(const default_delete<U>&) noexcept;
+
+    void operator()(T*) const noexcept;
+};
+
+template <class T>
+struct default_delete<T[]>
+{
+    constexpr default_delete() noexcept = default;
+    void operator()(T*) const noexcept;
+    template <class U> void operator()(U*) const = delete;
+};
+
+template <class T, class D = default_delete<T>>
+class unique_ptr
+{
+public:
+    typedef see below pointer;
+    typedef T element_type;
+    typedef D deleter_type;
+
+    // constructors
+    constexpr unique_ptr() noexcept;
+    explicit unique_ptr(pointer p) noexcept;
+    unique_ptr(pointer p, see below d1) noexcept;
+    unique_ptr(pointer p, see below d2) noexcept;
+    unique_ptr(unique_ptr&& u) noexcept;
+    unique_ptr(nullptr_t) noexcept : unique_ptr() { }
+    template <class U, class E>
+        unique_ptr(unique_ptr<U, E>&& u) noexcept;
+    template <class U>
+        unique_ptr(auto_ptr<U>&& u) noexcept;       // removed in C++17
+
+    // destructor
+    ~unique_ptr();
+
+    // assignment
+    unique_ptr& operator=(unique_ptr&& u) noexcept;
+    template <class U, class E> unique_ptr& operator=(unique_ptr<U, E>&& u) noexcept;
+    unique_ptr& operator=(nullptr_t) noexcept;
+
+    // observers
+    typename add_lvalue_reference<T>::type operator*() const;
+    pointer operator->() const noexcept;
+    pointer get() const noexcept;
+    deleter_type& get_deleter() noexcept;
+    const deleter_type& get_deleter() const noexcept;
+    explicit operator bool() const noexcept;
+
+    // modifiers
+    pointer release() noexcept;
+    void reset(pointer p = pointer()) noexcept;
+    void swap(unique_ptr& u) noexcept;
+};
+
+template <class T, class D>
+class unique_ptr<T[], D>
+{
+public:
+    typedef implementation-defined pointer;
+    typedef T element_type;
+    typedef D deleter_type;
+
+    // constructors
+    constexpr unique_ptr() noexcept;
+    explicit unique_ptr(pointer p) noexcept;
+    unique_ptr(pointer p, see below d) noexcept;
+    unique_ptr(pointer p, see below d) noexcept;
+    unique_ptr(unique_ptr&& u) noexcept;
+    unique_ptr(nullptr_t) noexcept : unique_ptr() { }
+
+    // destructor
+    ~unique_ptr();
+
+    // assignment
+    unique_ptr& operator=(unique_ptr&& u) noexcept;
+    unique_ptr& operator=(nullptr_t) noexcept;
+
+    // observers
+    T& operator[](size_t i) const;
+    pointer get() const noexcept;
+    deleter_type& get_deleter() noexcept;
+    const deleter_type& get_deleter() const noexcept;
+    explicit operator bool() const noexcept;
+
+    // modifiers
+    pointer release() noexcept;
+    void reset(pointer p = pointer()) noexcept;
+    void reset(nullptr_t) noexcept;
+  template <class U> void reset(U) = delete;
+    void swap(unique_ptr& u) noexcept;
+};
+
+template <class T, class D>
+    void swap(unique_ptr<T, D>& x, unique_ptr<T, D>& y) noexcept;
+
+template <class T1, class D1, class T2, class D2>
+    bool operator==(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
+template <class T1, class D1, class T2, class D2>
+    bool operator!=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
+template <class T1, class D1, class T2, class D2>
+    bool operator<(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
+template <class T1, class D1, class T2, class D2>
+    bool operator<=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
+template <class T1, class D1, class T2, class D2>
+    bool operator>(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
+template <class T1, class D1, class T2, class D2>
+    bool operator>=(const unique_ptr<T1, D1>& x, const unique_ptr<T2, D2>& y);
+
+template <class T, class D>
+    bool operator==(const unique_ptr<T, D>& x, nullptr_t) noexcept;
+template <class T, class D>
+    bool operator==(nullptr_t, const unique_ptr<T, D>& y) noexcept;
+template <class T, class D>
+    bool operator!=(const unique_ptr<T, D>& x, nullptr_t) noexcept;
+template <class T, class D>
+    bool operator!=(nullptr_t, const unique_ptr<T, D>& y) noexcept;
+
+template <class T, class D>
+    bool operator<(const unique_ptr<T, D>& x, nullptr_t);
+template <class T, class D>
+    bool operator<(nullptr_t, const unique_ptr<T, D>& y);
+template <class T, class D>
+    bool operator<=(const unique_ptr<T, D>& x, nullptr_t);
+template <class T, class D>
+    bool operator<=(nullptr_t, const unique_ptr<T, D>& y);
+template <class T, class D>
+    bool operator>(const unique_ptr<T, D>& x, nullptr_t);
+template <class T, class D>
+    bool operator>(nullptr_t, const unique_ptr<T, D>& y);
+template <class T, class D>
+    bool operator>=(const unique_ptr<T, D>& x, nullptr_t);
+template <class T, class D>
+    bool operator>=(nullptr_t, const unique_ptr<T, D>& y);
+
+class bad_weak_ptr
+    : public std::exception
+{
+    bad_weak_ptr() noexcept;
+};
+
+template<class T, class... Args> unique_ptr<T> make_unique(Args&&... args);     // C++14
+template<class T>                unique_ptr<T> make_unique(size_t n);           // C++14
+template<class T, class... Args> unspecified   make_unique(Args&&...) = delete; // C++14, T == U[N]
+
+template<class E, class T, class Y, class D>
+    basic_ostream<E, T>& operator<< (basic_ostream<E, T>& os, unique_ptr<Y, D> const& p);
+
+template<class T>
+class shared_ptr
+{
+public:
+    typedef T element_type;
+    typedef weak_ptr<T> weak_type; // C++17
+
+    // constructors:
+    constexpr shared_ptr() noexcept;
+    template<class Y> explicit shared_ptr(Y* p);
+    template<class Y, class D> shared_ptr(Y* p, D d);
+    template<class Y, class D, class A> shared_ptr(Y* p, D d, A a);
+    template <class D> shared_ptr(nullptr_t p, D d);
+    template <class D, class A> shared_ptr(nullptr_t p, D d, A a);
+    template<class Y> shared_ptr(const shared_ptr<Y>& r, T *p) noexcept;
+    shared_ptr(const shared_ptr& r) noexcept;
+    template<class Y> shared_ptr(const shared_ptr<Y>& r) noexcept;
+    shared_ptr(shared_ptr&& r) noexcept;
+    template<class Y> shared_ptr(shared_ptr<Y>&& r) noexcept;
+    template<class Y> explicit shared_ptr(const weak_ptr<Y>& r);
+    template<class Y> shared_ptr(auto_ptr<Y>&& r);          // removed in C++17
+    template <class Y, class D> shared_ptr(unique_ptr<Y, D>&& r);
+    shared_ptr(nullptr_t) : shared_ptr() { }
+
+    // destructor:
+    ~shared_ptr();
+
+    // assignment:
+    shared_ptr& operator=(const shared_ptr& r) noexcept;
+    template<class Y> shared_ptr& operator=(const shared_ptr<Y>& r) noexcept;
+    shared_ptr& operator=(shared_ptr&& r) noexcept;
+    template<class Y> shared_ptr& operator=(shared_ptr<Y>&& r);
+    template<class Y> shared_ptr& operator=(auto_ptr<Y>&& r); // removed in C++17
+    template <class Y, class D> shared_ptr& operator=(unique_ptr<Y, D>&& r);
+
+    // modifiers:
+    void swap(shared_ptr& r) noexcept;
+    void reset() noexcept;
+    template<class Y> void reset(Y* p);
+    template<class Y, class D> void reset(Y* p, D d);
+    template<class Y, class D, class A> void reset(Y* p, D d, A a);
+
+    // observers:
+    T* get() const noexcept;
+    T& operator*() const noexcept;
+    T* operator->() const noexcept;
+    long use_count() const noexcept;
+    bool unique() const noexcept;
+    explicit operator bool() const noexcept;
+    template<class U> bool owner_before(shared_ptr<U> const& b) const noexcept;
+    template<class U> bool owner_before(weak_ptr<U> const& b) const noexcept;
+};
+
+template<class T>
+shared_ptr(weak_ptr<T>) -> shared_ptr<T>;
+template<class T, class D>
+shared_ptr(unique_ptr<T, D>) -> shared_ptr<T>;
+
+// shared_ptr comparisons:
+template<class T, class U>
+    bool operator==(shared_ptr<T> const& a, shared_ptr<U> const& b) noexcept;
+template<class T, class U>
+    bool operator!=(shared_ptr<T> const& a, shared_ptr<U> const& b) noexcept;
+template<class T, class U>
+    bool operator<(shared_ptr<T> const& a, shared_ptr<U> const& b) noexcept;
+template<class T, class U>
+    bool operator>(shared_ptr<T> const& a, shared_ptr<U> const& b) noexcept;
+template<class T, class U>
+    bool operator<=(shared_ptr<T> const& a, shared_ptr<U> const& b) noexcept;
+template<class T, class U>
+    bool operator>=(shared_ptr<T> const& a, shared_ptr<U> const& b) noexcept;
+
+template <class T>
+    bool operator==(const shared_ptr<T>& x, nullptr_t) noexcept;
+template <class T>
+    bool operator==(nullptr_t, const shared_ptr<T>& y) noexcept;
+template <class T>
+    bool operator!=(const shared_ptr<T>& x, nullptr_t) noexcept;
+template <class T>
+    bool operator!=(nullptr_t, const shared_ptr<T>& y) noexcept;
+template <class T>
+    bool operator<(const shared_ptr<T>& x, nullptr_t) noexcept;
+template <class T>
+bool operator<(nullptr_t, const shared_ptr<T>& y) noexcept;
+template <class T>
+    bool operator<=(const shared_ptr<T>& x, nullptr_t) noexcept;
+template <class T>
+    bool operator<=(nullptr_t, const shared_ptr<T>& y) noexcept;
+template <class T>
+    bool operator>(const shared_ptr<T>& x, nullptr_t) noexcept;
+template <class T>
+    bool operator>(nullptr_t, const shared_ptr<T>& y) noexcept;
+template <class T>
+    bool operator>=(const shared_ptr<T>& x, nullptr_t) noexcept;
+template <class T>
+    bool operator>=(nullptr_t, const shared_ptr<T>& y) noexcept;
+
+// shared_ptr specialized algorithms:
+template<class T> void swap(shared_ptr<T>& a, shared_ptr<T>& b) noexcept;
+
+// shared_ptr casts:
+template<class T, class U>
+    shared_ptr<T> static_pointer_cast(shared_ptr<U> const& r) noexcept;
+template<class T, class U>
+    shared_ptr<T> dynamic_pointer_cast(shared_ptr<U> const& r) noexcept;
+template<class T, class U>
+    shared_ptr<T> const_pointer_cast(shared_ptr<U> const& r) noexcept;
+
+// shared_ptr I/O:
+template<class E, class T, class Y>
+    basic_ostream<E, T>& operator<< (basic_ostream<E, T>& os, shared_ptr<Y> const& p);
+
+// shared_ptr get_deleter:
+template<class D, class T> D* get_deleter(shared_ptr<T> const& p) noexcept;
+
+template<class T, class... Args>
+    shared_ptr<T> make_shared(Args&&... args);
+template<class T, class A, class... Args>
+    shared_ptr<T> allocate_shared(const A& a, Args&&... args);
+
+template<class T>
+class weak_ptr
+{
+public:
+    typedef T element_type;
+
+    // constructors
+    constexpr weak_ptr() noexcept;
+    template<class Y> weak_ptr(shared_ptr<Y> const& r) noexcept;
+    weak_ptr(weak_ptr const& r) noexcept;
+    template<class Y> weak_ptr(weak_ptr<Y> const& r) noexcept;
+    weak_ptr(weak_ptr&& r) noexcept;                      // C++14
+    template<class Y> weak_ptr(weak_ptr<Y>&& r) noexcept; // C++14
+
+    // destructor
+    ~weak_ptr();
+
+    // assignment
+    weak_ptr& operator=(weak_ptr const& r) noexcept;
+    template<class Y> weak_ptr& operator=(weak_ptr<Y> const& r) noexcept;
+    template<class Y> weak_ptr& operator=(shared_ptr<Y> const& r) noexcept;
+    weak_ptr& operator=(weak_ptr&& r) noexcept;                      // C++14
+    template<class Y> weak_ptr& operator=(weak_ptr<Y>&& r) noexcept; // C++14
+
+    // modifiers
+    void swap(weak_ptr& r) noexcept;
+    void reset() noexcept;
+
+    // observers
+    long use_count() const noexcept;
+    bool expired() const noexcept;
+    shared_ptr<T> lock() const noexcept;
+    template<class U> bool owner_before(shared_ptr<U> const& b) const noexcept;
+    template<class U> bool owner_before(weak_ptr<U> const& b) const noexcept;
+};
+
+template<class T>
+weak_ptr(shared_ptr<T>) -> weak_ptr<T>;
+
+// weak_ptr specialized algorithms:
+template<class T> void swap(weak_ptr<T>& a, weak_ptr<T>& b) noexcept;
+
+// class owner_less:
+template<class T> struct owner_less;
+
+template<class T>
+struct owner_less<shared_ptr<T> >
+    : binary_function<shared_ptr<T>, shared_ptr<T>, bool>
+{
+    typedef bool result_type;
+    bool operator()(shared_ptr<T> const&, shared_ptr<T> const&) const noexcept;
+    bool operator()(shared_ptr<T> const&, weak_ptr<T> const&) const noexcept;
+    bool operator()(weak_ptr<T> const&, shared_ptr<T> const&) const noexcept;
+};
+
+template<class T>
+struct owner_less<weak_ptr<T> >
+    : binary_function<weak_ptr<T>, weak_ptr<T>, bool>
+{
+    typedef bool result_type;
+    bool operator()(weak_ptr<T> const&, weak_ptr<T> const&) const noexcept;
+    bool operator()(shared_ptr<T> const&, weak_ptr<T> const&) const noexcept;
+    bool operator()(weak_ptr<T> const&, shared_ptr<T> const&) const noexcept;
+};
+
+template <>  // Added in C++14
+struct owner_less<void>
+{
+    template <class _Tp, class _Up>
+    bool operator()( shared_ptr<_Tp> const& __x, shared_ptr<_Up> const& __y) const noexcept;
+    template <class _Tp, class _Up>
+    bool operator()( shared_ptr<_Tp> const& __x,   weak_ptr<_Up> const& __y) const noexcept;
+    template <class _Tp, class _Up>
+    bool operator()(   weak_ptr<_Tp> const& __x, shared_ptr<_Up> const& __y) const noexcept;
+    template <class _Tp, class _Up>
+    bool operator()(   weak_ptr<_Tp> const& __x,   weak_ptr<_Up> const& __y) const noexcept;
+
+    typedef void is_transparent;
+};
+
+template<class T>
+class enable_shared_from_this
+{
+protected:
+    constexpr enable_shared_from_this() noexcept;
+    enable_shared_from_this(enable_shared_from_this const&) noexcept;
+    enable_shared_from_this& operator=(enable_shared_from_this const&) noexcept;
+    ~enable_shared_from_this();
+public:
+    shared_ptr<T> shared_from_this();
+    shared_ptr<T const> shared_from_this() const;
+};
+
+template<class T>
+    bool atomic_is_lock_free(const shared_ptr<T>* p);
+template<class T>
+    shared_ptr<T> atomic_load(const shared_ptr<T>* p);
+template<class T>
+    shared_ptr<T> atomic_load_explicit(const shared_ptr<T>* p, memory_order mo);
+template<class T>
+    void atomic_store(shared_ptr<T>* p, shared_ptr<T> r);
+template<class T>
+    void atomic_store_explicit(shared_ptr<T>* p, shared_ptr<T> r, memory_order mo);
+template<class T>
+    shared_ptr<T> atomic_exchange(shared_ptr<T>* p, shared_ptr<T> r);
+template<class T>
+    shared_ptr<T>
+    atomic_exchange_explicit(shared_ptr<T>* p, shared_ptr<T> r, memory_order mo);
+template<class T>
+    bool
+    atomic_compare_exchange_weak(shared_ptr<T>* p, shared_ptr<T>* v, shared_ptr<T> w);
+template<class T>
+    bool
+    atomic_compare_exchange_strong( shared_ptr<T>* p, shared_ptr<T>* v, shared_ptr<T> w);
+template<class T>
+    bool
+    atomic_compare_exchange_weak_explicit(shared_ptr<T>* p, shared_ptr<T>* v,
+                                          shared_ptr<T> w, memory_order success,
+                                          memory_order failure);
+template<class T>
+    bool
+    atomic_compare_exchange_strong_explicit(shared_ptr<T>* p, shared_ptr<T>* v,
+                                            shared_ptr<T> w, memory_order success,
+                                            memory_order failure);
+// Hash support
+template <class T> struct hash;
+template <class T, class D> struct hash<unique_ptr<T, D> >;
+template <class T> struct hash<shared_ptr<T> >;
+
+template <class T, class Alloc>
+  inline constexpr bool uses_allocator_v = uses_allocator<T, Alloc>::value;
+
+// Pointer safety
+enum class pointer_safety { relaxed, preferred, strict }; // since C++11
+void declare_reachable(void *p);                          // since C++11
+template <class T> T *undeclare_reachable(T *p);          // since C++11
+void declare_no_pointers(char *p, size_t n);              // since C++11
+void undeclare_no_pointers(char *p, size_t n);            // since C++11
+pointer_safety get_pointer_safety() noexcept;             // since C++11
+
+void* align(size_t alignment, size_t size, void*& ptr, size_t& space);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__functional_base>
+#include <__memory/addressof.h>
+#include <__memory/allocation_guard.h>
+#include <__memory/allocator.h>
+#include <__memory/allocator_arg_t.h>
+#include <__memory/allocator_traits.h>
+#include <__memory/compressed_pair.h>
+#include <__memory/construct_at.h>
+#include <__memory/pointer_safety.h>
+#include <__memory/pointer_traits.h>
+#include <__memory/raw_storage_iterator.h>
+#include <__memory/shared_ptr.h>
+#include <__memory/temporary_buffer.h>
+#include <__memory/uninitialized_algorithms.h>
+#include <__memory/unique_ptr.h>
+#include <__memory/uses_allocator.h>
+#include <compare>
+#include <cstddef>
+#include <cstdint>
+#include <cstring>
+#include <iosfwd>
+#include <iterator>
+#include <new>
+#include <stdexcept>
+#include <stlfwd>
+#include <tuple>
+#include <type_traits>
+#include <typeinfo>
+#include <utility>
+#include <version>
+
+#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR)
+#   include <__memory/auto_ptr.h>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Alloc, class _Ptr>
+_LIBCPP_INLINE_VISIBILITY
+void __construct_forward_with_exception_guarantees(_Alloc& __a, _Ptr __begin1, _Ptr __end1, _Ptr& __begin2) {
+    static_assert(__is_cpp17_move_insertable<_Alloc>::value,
+        "The specified type does not meet the requirements of Cpp17MoveInsertable");
+    typedef allocator_traits<_Alloc> _Traits;
+    for (; __begin1 != __end1; ++__begin1, (void)++__begin2) {
+        _Traits::construct(__a, _VSTD::__to_address(__begin2),
+#ifdef _LIBCPP_NO_EXCEPTIONS
+            _VSTD::move(*__begin1)
+#else
+            _VSTD::move_if_noexcept(*__begin1)
+#endif
+        );
+    }
+}
+
+template <class _Alloc, class _Tp, typename enable_if<
+    (__is_default_allocator<_Alloc>::value || !__has_construct<_Alloc, _Tp*, _Tp>::value) &&
+    is_trivially_move_constructible<_Tp>::value
+>::type>
+_LIBCPP_INLINE_VISIBILITY
+void __construct_forward_with_exception_guarantees(_Alloc&, _Tp* __begin1, _Tp* __end1, _Tp*& __begin2) {
+    ptrdiff_t _Np = __end1 - __begin1;
+    if (_Np > 0) {
+        _VSTD::memcpy(__begin2, __begin1, _Np * sizeof(_Tp));
+        __begin2 += _Np;
+    }
+}
+
+template <class _Alloc, class _Iter, class _Ptr>
+_LIBCPP_INLINE_VISIBILITY
+void __construct_range_forward(_Alloc& __a, _Iter __begin1, _Iter __end1, _Ptr& __begin2) {
+    typedef allocator_traits<_Alloc> _Traits;
+    for (; __begin1 != __end1; ++__begin1, (void) ++__begin2) {
+        _Traits::construct(__a, _VSTD::__to_address(__begin2), *__begin1);
+    }
+}
+
+template <class _Alloc, class _Source, class _Dest,
+          class _RawSource = typename remove_const<_Source>::type,
+          class _RawDest = typename remove_const<_Dest>::type,
+          class =
+    typename enable_if<
+        is_trivially_copy_constructible<_Dest>::value &&
+        is_same<_RawSource, _RawDest>::value &&
+        (__is_default_allocator<_Alloc>::value || !__has_construct<_Alloc, _Dest*, _Source&>::value)
+    >::type>
+_LIBCPP_INLINE_VISIBILITY
+void __construct_range_forward(_Alloc&, _Source* __begin1, _Source* __end1, _Dest*& __begin2) {
+    ptrdiff_t _Np = __end1 - __begin1;
+    if (_Np > 0) {
+        _VSTD::memcpy(const_cast<_RawDest*>(__begin2), __begin1, _Np * sizeof(_Dest));
+        __begin2 += _Np;
+    }
+}
+
+template <class _Alloc, class _Ptr>
+_LIBCPP_INLINE_VISIBILITY
+void __construct_backward_with_exception_guarantees(_Alloc& __a, _Ptr __begin1, _Ptr __end1, _Ptr& __end2) {
+    static_assert(__is_cpp17_move_insertable<_Alloc>::value,
+        "The specified type does not meet the requirements of Cpp17MoveInsertable");
+    typedef allocator_traits<_Alloc> _Traits;
+    while (__end1 != __begin1) {
+        _Traits::construct(__a, _VSTD::__to_address(__end2 - 1),
+#ifdef _LIBCPP_NO_EXCEPTIONS
+            _VSTD::move(*--__end1)
+#else
+            _VSTD::move_if_noexcept(*--__end1)
+#endif
+        );
+        --__end2;
+    }
+}
+
+template <class _Alloc, class _Tp, class = typename enable_if<
+    (__is_default_allocator<_Alloc>::value || !__has_construct<_Alloc, _Tp*, _Tp>::value) &&
+    is_trivially_move_constructible<_Tp>::value
+>::type>
+_LIBCPP_INLINE_VISIBILITY
+void __construct_backward_with_exception_guarantees(_Alloc&, _Tp* __begin1, _Tp* __end1, _Tp*& __end2) {
+    ptrdiff_t _Np = __end1 - __begin1;
+    __end2 -= _Np;
+    if (_Np > 0)
+        _VSTD::memcpy(static_cast<void*>(__end2), static_cast<void const*>(__begin1), _Np * sizeof(_Tp));
+}
+
+struct __destruct_n
+{
+private:
+    size_t __size_;
+
+    template <class _Tp>
+    _LIBCPP_INLINE_VISIBILITY void __process(_Tp* __p, false_type) _NOEXCEPT
+        {for (size_t __i = 0; __i < __size_; ++__i, ++__p) __p->~_Tp();}
+
+    template <class _Tp>
+    _LIBCPP_INLINE_VISIBILITY void __process(_Tp*, true_type) _NOEXCEPT
+        {}
+
+    _LIBCPP_INLINE_VISIBILITY void __incr(false_type) _NOEXCEPT
+        {++__size_;}
+    _LIBCPP_INLINE_VISIBILITY void __incr(true_type) _NOEXCEPT
+        {}
+
+    _LIBCPP_INLINE_VISIBILITY void __set(size_t __s, false_type) _NOEXCEPT
+        {__size_ = __s;}
+    _LIBCPP_INLINE_VISIBILITY void __set(size_t, true_type) _NOEXCEPT
+        {}
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit __destruct_n(size_t __s) _NOEXCEPT
+        : __size_(__s) {}
+
+    template <class _Tp>
+    _LIBCPP_INLINE_VISIBILITY void __incr() _NOEXCEPT
+        {__incr(integral_constant<bool, is_trivially_destructible<_Tp>::value>());}
+
+    template <class _Tp>
+    _LIBCPP_INLINE_VISIBILITY void __set(size_t __s, _Tp*) _NOEXCEPT
+        {__set(__s, integral_constant<bool, is_trivially_destructible<_Tp>::value>());}
+
+    template <class _Tp>
+    _LIBCPP_INLINE_VISIBILITY void operator()(_Tp* __p) _NOEXCEPT
+        {__process(__p, integral_constant<bool, is_trivially_destructible<_Tp>::value>());}
+};
+
+_LIBCPP_FUNC_VIS void* align(size_t __align, size_t __sz, void*& __ptr, size_t& __space);
+
+// --- Helper for container swap --
+template <typename _Alloc>
+_LIBCPP_INLINE_VISIBILITY
+void __swap_allocator(_Alloc & __a1, _Alloc & __a2, true_type)
+#if _LIBCPP_STD_VER >= 14
+    _NOEXCEPT
+#else
+    _NOEXCEPT_(__is_nothrow_swappable<_Alloc>::value)
+#endif
+{
+    using _VSTD::swap;
+    swap(__a1, __a2);
+}
+
+template <typename _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void __swap_allocator(_Alloc &, _Alloc &, false_type) _NOEXCEPT {}
+
+template <typename _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void __swap_allocator(_Alloc & __a1, _Alloc & __a2)
+#if _LIBCPP_STD_VER >= 14
+    _NOEXCEPT
+#else
+    _NOEXCEPT_(__is_nothrow_swappable<_Alloc>::value)
+#endif
+{
+    _VSTD::__swap_allocator(__a1, __a2,
+      integral_constant<bool, allocator_traits<_Alloc>::propagate_on_container_swap::value>());
+}
+
+template <typename _Alloc, typename _Traits=allocator_traits<_Alloc> >
+struct __noexcept_move_assign_container : public integral_constant<bool,
+    _Traits::propagate_on_container_move_assignment::value
+#if _LIBCPP_STD_VER > 14
+        || _Traits::is_always_equal::value
+#else
+        && is_nothrow_move_assignable<_Alloc>::value
+#endif
+    > {};
+
+
+template <class _Tp, class _Alloc>
+struct __temp_value {
+    typedef allocator_traits<_Alloc> _Traits;
+
+    typename aligned_storage<sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)>::type __v;
+    _Alloc &__a;
+
+    _Tp *__addr() { return reinterpret_cast<_Tp *>(addressof(__v)); }
+    _Tp &   get() { return *__addr(); }
+
+    template<class... _Args>
+    _LIBCPP_NO_CFI
+    __temp_value(_Alloc &__alloc, _Args&& ... __args) : __a(__alloc) {
+      _Traits::construct(__a, reinterpret_cast<_Tp*>(addressof(__v)),
+                         _VSTD::forward<_Args>(__args)...);
+    }
+
+    ~__temp_value() { _Traits::destroy(__a, __addr()); }
+    };
+
+template<typename _Alloc, typename = void, typename = void>
+struct __is_allocator : false_type {};
+
+template<typename _Alloc>
+struct __is_allocator<_Alloc,
+       typename __void_t<typename _Alloc::value_type>::type,
+       typename __void_t<decltype(declval<_Alloc&>().allocate(size_t(0)))>::type
+     >
+   : true_type {};
+
+// __builtin_new_allocator -- A non-templated helper for allocating and
+// deallocating memory using __builtin_operator_new and
+// __builtin_operator_delete. It should be used in preference to
+// `std::allocator<T>` to avoid additional instantiations.
+struct __builtin_new_allocator {
+  struct __builtin_new_deleter {
+    typedef void* pointer_type;
+
+    _LIBCPP_CONSTEXPR explicit __builtin_new_deleter(size_t __size, size_t __align)
+        : __size_(__size), __align_(__align) {}
+
+    void operator()(void* p) const _NOEXCEPT {
+        _VSTD::__libcpp_deallocate(p, __size_, __align_);
+    }
+
+   private:
+    size_t __size_;
+    size_t __align_;
+  };
+
+  typedef unique_ptr<void, __builtin_new_deleter> __holder_t;
+
+  static __holder_t __allocate_bytes(size_t __s, size_t __align) {
+      return __holder_t(_VSTD::__libcpp_allocate(__s, __align),
+                     __builtin_new_deleter(__s, __align));
+  }
+
+  static void __deallocate_bytes(void* __p, size_t __s,
+                                 size_t __align) _NOEXCEPT {
+      _VSTD::__libcpp_deallocate(__p, __s, __align);
+  }
+
+  template <class _Tp>
+  _LIBCPP_NODEBUG _LIBCPP_ALWAYS_INLINE
+  static __holder_t __allocate_type(size_t __n) {
+      return __allocate_bytes(__n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp));
+  }
+
+  template <class _Tp>
+  _LIBCPP_NODEBUG _LIBCPP_ALWAYS_INLINE
+  static void __deallocate_type(void* __p, size_t __n) _NOEXCEPT {
+      __deallocate_bytes(__p, __n * sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp));
+  }
+};
+
+
+_LIBCPP_END_NAMESPACE_STD
+
+#if defined(_LIBCPP_HAS_PARALLEL_ALGORITHMS) && _LIBCPP_STD_VER >= 17
+//#   include <__pstl_memory>
+#endif
+
+#endif // _LIBCPP_MEMORY
diff --git a/contrib/libs/cxxsupp/libcxx/include/module.modulemap b/contrib/libs/cxxsupp/libcxx/include/module.modulemap
new file mode 100644
index 00000000000..80cdfe323f7
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/module.modulemap
@@ -0,0 +1,978 @@
+// define the module for __config outside of the top level 'std' module
+// since __config may be included from C headers which may create an
+// include cycle.
+module std_config [system] [extern_c] {
+    header "__config"
+}
+
+module std [system] {
+  export std_config
+  // FIXME: The standard does not require that each of these submodules
+  // re-exports its imported modules. We should provide an alternative form of
+  // export that issues a warning if a name from the submodule is used, and
+  // use that to provide a 'strict mode' for libc++.
+
+  // Deprecated C-compatibility headers. These can all be included from within
+  // an 'extern "C"' context.
+  module depr [extern_c] {
+    // <assert.h> provided by C library.
+    module ctype_h {
+      header "ctype.h"
+      export *
+    }
+    module errno_h {
+      header "errno.h"
+      export *
+    }
+    module fenv_h {
+      header "fenv.h"
+      export *
+    }
+    // <float.h> provided by compiler or C library.
+    module inttypes_h {
+      header "inttypes.h"
+      export stdint_h
+      export *
+    }
+    // <iso646.h> provided by compiler.
+    // <limits.h> provided by compiler or C library.
+    module locale_h {
+      header "locale.h"
+      export *
+    }
+    module math_h {
+      header "math.h"
+      export *
+    }
+    module setjmp_h {
+      header "setjmp.h"
+      export *
+    }
+    // FIXME: <stdalign.h> is missing.
+    // <signal.h> provided by C library.
+    // <stdarg.h> provided by compiler.
+    // <stdbool.h> provided by compiler.
+    module stddef_h {
+      // <stddef.h>'s __need_* macros require textual inclusion.
+      textual header "stddef.h"
+    }
+    module stdint_h {
+      header "stdint.h"
+      export *
+      // FIXME: This module only exists on OS X and for some reason the
+      // wildcard above doesn't export it.
+      export Darwin.C.stdint
+    }
+    module stdio_h {
+      // <stdio.h>'s __need_* macros require textual inclusion.
+      textual header "stdio.h"
+      export *
+      export Darwin.C.stdio
+    }
+    module stdlib_h {
+      // <stdlib.h>'s __need_* macros require textual inclusion.
+      textual header "stdlib.h"
+      export *
+    }
+    module string_h {
+      header "string.h"
+      export *
+    }
+    // FIXME: <uchar.h> is missing.
+    // <time.h> provided by C library.
+    module wchar_h {
+      // <wchar.h>'s __need_* macros require textual inclusion.
+      textual header "wchar.h"
+      export *
+    }
+    module wctype_h {
+      header "wctype.h"
+      export *
+    }
+  }
+
+  // <complex.h> and <tgmath.h> are not C headers in any real sense, do not
+  // allow their use in extern "C" contexts.
+  module complex_h {
+    header "complex.h"
+    export ccomplex
+    export *
+  }
+  module tgmath_h {
+    header "tgmath.h"
+    export ccomplex
+    export cmath
+    export *
+  }
+
+  // C compatibility headers.
+  module compat {
+    module cassert {
+      // <cassert>'s use of NDEBUG requires textual inclusion.
+      textual header "cassert"
+    }
+    module ccomplex {
+      header "ccomplex"
+      export complex
+      export *
+    }
+    module cctype {
+      header "cctype"
+      export *
+    }
+    module cerrno {
+      header "cerrno"
+      export *
+    }
+    module cfenv {
+      header "cfenv"
+      export *
+    }
+    module cfloat {
+      header "cfloat"
+      export *
+    }
+    module cinttypes {
+      header "cinttypes"
+      export cstdint
+      export *
+    }
+    module ciso646 {
+      header "ciso646"
+      export *
+    }
+    module climits {
+      header "climits"
+      export *
+    }
+    module clocale {
+      header "clocale"
+      export *
+    }
+    module cmath {
+      header "cmath"
+      export *
+    }
+    module csetjmp {
+      header "csetjmp"
+      export *
+    }
+    module csignal {
+      header "csignal"
+      export *
+    }
+    // FIXME: <cstdalign> is missing.
+    module cstdarg {
+      header "cstdarg"
+      export *
+    }
+    module cstdbool {
+      header "cstdbool"
+      export *
+    }
+    module cstddef {
+      header "cstddef"
+      export *
+    }
+    module cstdint {
+      header "cstdint"
+      export depr.stdint_h
+      export *
+    }
+    module cstdio {
+      header "cstdio"
+      export *
+    }
+    module cstdlib {
+      header "cstdlib"
+      export *
+    }
+    module cstring {
+      header "cstring"
+      export *
+    }
+    module ctgmath {
+      header "ctgmath"
+      export ccomplex
+      export cmath
+      export *
+    }
+    module ctime {
+      header "ctime"
+      export *
+    }
+    // FIXME: <cuchar> is missing.
+    module cwchar {
+      header "cwchar"
+      export depr.stdio_h
+      export *
+    }
+    module cwctype {
+      header "cwctype"
+      export *
+    }
+  }
+
+  module algorithm {
+    header "algorithm"
+    export initializer_list
+    export *
+
+    module __algorithm {
+      module adjacent_find            { private header "__algorithm/adjacent_find.h" }
+      module all_of                   { private header "__algorithm/all_of.h" }
+      module any_of                   { private header "__algorithm/any_of.h" }
+      module binary_search            { private header "__algorithm/binary_search.h" }
+      module clamp                    { private header "__algorithm/clamp.h" }
+      module comp                     { private header "__algorithm/comp.h" }
+      module comp_ref_type            { private header "__algorithm/comp_ref_type.h" }
+      module copy                     { private header "__algorithm/copy.h" }
+      module copy_backward            { private header "__algorithm/copy_backward.h" }
+      module copy_if                  { private header "__algorithm/copy_if.h" }
+      module copy_n                   { private header "__algorithm/copy_n.h" }
+      module count                    { private header "__algorithm/count.h" }
+      module count_if                 { private header "__algorithm/count_if.h" }
+      module equal                    { private header "__algorithm/equal.h" }
+      module equal_range              { private header "__algorithm/equal_range.h" }
+      module fill                     { private header "__algorithm/fill.h" }
+      module fill_n                   { private header "__algorithm/fill_n.h" }
+      module find                     { private header "__algorithm/find.h" }
+      module find_end                 { private header "__algorithm/find_end.h" }
+      module find_first_of            { private header "__algorithm/find_first_of.h" }
+      module find_if                  { private header "__algorithm/find_if.h" }
+      module find_if_not              { private header "__algorithm/find_if_not.h" }
+      module for_each                 { private header "__algorithm/for_each.h" }
+      module for_each_n               { private header "__algorithm/for_each_n.h" }
+      module generate                 { private header "__algorithm/generate.h" }
+      module generate_n               { private header "__algorithm/generate_n.h" }
+      module half_positive            { private header "__algorithm/half_positive.h" }
+      module includes                 { private header "__algorithm/includes.h" }
+      module inplace_merge            { private header "__algorithm/inplace_merge.h" }
+      module is_heap                  { private header "__algorithm/is_heap.h" }
+      module is_heap_until            { private header "__algorithm/is_heap_until.h" }
+      module is_partitioned           { private header "__algorithm/is_partitioned.h" }
+      module is_permutation           { private header "__algorithm/is_permutation.h" }
+      module is_sorted                { private header "__algorithm/is_sorted.h" }
+      module is_sorted_until          { private header "__algorithm/is_sorted_until.h" }
+      module iter_swap                { private header "__algorithm/iter_swap.h" }
+      module lexicographical_compare  { private header "__algorithm/lexicographical_compare.h" }
+      module lower_bound              { private header "__algorithm/lower_bound.h" }
+      module make_heap                { private header "__algorithm/make_heap.h" }
+      module max                      { private header "__algorithm/max.h" }
+      module max_element              { private header "__algorithm/max_element.h" }
+      module merge                    { private header "__algorithm/merge.h" }
+      module min                      { private header "__algorithm/min.h" }
+      module min_element              { private header "__algorithm/min_element.h" }
+      module minmax                   { private header "__algorithm/minmax.h" }
+      module minmax_element           { private header "__algorithm/minmax_element.h" }
+      module mismatch                 { private header "__algorithm/mismatch.h" }
+      module move                     { private header "__algorithm/move.h" }
+      module move_backward            { private header "__algorithm/move_backward.h" }
+      module next_permutation         { private header "__algorithm/next_permutation.h" }
+      module none_of                  { private header "__algorithm/none_of.h" }
+      module nth_element              { private header "__algorithm/nth_element.h" }
+      module partial_sort             { private header "__algorithm/partial_sort.h" }
+      module partial_sort_copy        { private header "__algorithm/partial_sort_copy.h" }
+      module partition                { private header "__algorithm/partition.h" }
+      module partition_copy           { private header "__algorithm/partition_copy.h" }
+      module partition_point          { private header "__algorithm/partition_point.h" }
+      module pop_heap                 { private header "__algorithm/pop_heap.h" }
+      module prev_permutation         { private header "__algorithm/prev_permutation.h" }
+      module push_heap                { private header "__algorithm/push_heap.h" }
+      module remove                   { private header "__algorithm/remove.h" }
+      module remove_copy              { private header "__algorithm/remove_copy.h" }
+      module remove_copy_if           { private header "__algorithm/remove_copy_if.h" }
+      module remove_if                { private header "__algorithm/remove_if.h" }
+      module replace                  { private header "__algorithm/replace.h" }
+      module replace_copy             { private header "__algorithm/replace_copy.h" }
+      module replace_copy_if          { private header "__algorithm/replace_copy_if.h" }
+      module replace_if               { private header "__algorithm/replace_if.h" }
+      module reverse                  { private header "__algorithm/reverse.h" }
+      module reverse_copy             { private header "__algorithm/reverse_copy.h" }
+      module rotate                   { private header "__algorithm/rotate.h" }
+      module rotate_copy              { private header "__algorithm/rotate_copy.h" }
+      module sample                   { private header "__algorithm/sample.h" }
+      module search                   { private header "__algorithm/search.h" }
+      module search_n                 { private header "__algorithm/search_n.h" }
+      module set_difference           { private header "__algorithm/set_difference.h" }
+      module set_intersection         { private header "__algorithm/set_intersection.h" }
+      module set_symmetric_difference { private header "__algorithm/set_symmetric_difference.h" }
+      module set_union                { private header "__algorithm/set_union.h" }
+      module shift_left               { private header "__algorithm/shift_left.h" }
+      module shift_right              { private header "__algorithm/shift_right.h" }
+      module shuffle                  { private header "__algorithm/shuffle.h" }
+      module sift_down                { private header "__algorithm/sift_down.h" }
+      module sort                     { private header "__algorithm/sort.h" }
+      module sort_heap                { private header "__algorithm/sort_heap.h" }
+      module stable_partition         { private header "__algorithm/stable_partition.h" }
+      module stable_sort              { private header "__algorithm/stable_sort.h" }
+      module swap_ranges              { private header "__algorithm/swap_ranges.h" }
+      module transform                { private header "__algorithm/transform.h" }
+      module unique                   { private header "__algorithm/unique.h" }
+      module unique_copy              { private header "__algorithm/unique_copy.h" }
+      module unwrap_iter              { private header "__algorithm/unwrap_iter.h" }
+      module upper_bound              { private header "__algorithm/upper_bound.h" }
+    }
+  }
+  module any {
+    header "any"
+    export *
+  }
+  module array {
+    header "array"
+    export initializer_list
+    export *
+  }
+  module atomic {
+    header "atomic"
+    export *
+  }
+  module barrier {
+    requires cplusplus14
+    header "barrier"
+    export *
+  }
+  module bit {
+    header "bit"
+    export *
+
+    module __bit {
+      module bit_cast { private header "__bit/bit_cast.h" }
+    }
+  }
+  module bitset {
+    header "bitset"
+    export string
+    export iosfwd
+    export *
+  }
+  // No submodule for cassert. It fundamentally needs repeated, textual inclusion.
+  module charconv {
+    header "charconv"
+    export *
+
+    module __charconv {
+      module chars_format      { private header "__charconv/chars_format.h"      }
+      module from_chars_result { private header "__charconv/from_chars_result.h" }
+      module to_chars_result   { private header "__charconv/to_chars_result.h"   }
+    }
+
+  }
+  module chrono {
+    header "chrono"
+    export *
+  }
+  module codecvt {
+    header "codecvt"
+    export *
+  }
+  module compare {
+    header "compare"
+    export *
+
+    module __compare {
+      module common_comparison_category { private header "__compare/common_comparison_category.h" }
+      module compare_three_way          { private header "__compare/compare_three_way.h"          }
+      module compare_three_way_result   { private header "__compare/compare_three_way_result.h"   }
+      module is_eq                      { private header "__compare/is_eq.h"                      }
+      module ordering                   { private header "__compare/ordering.h"                   }
+      module synth_three_way            { private header "__compare/synth_three_way.h"            }
+      module three_way_comparable       { private header "__compare/three_way_comparable.h"       }
+    }
+  }
+  module complex {
+    header "complex"
+    export *
+  }
+  module concepts {
+    header "concepts"
+    export *
+
+    module __concepts {
+      module arithmetic                 { private header "__concepts/arithmetic.h"                }
+      module assignable                 { private header "__concepts/assignable.h"                }
+      module boolean_testable           { private header "__concepts/boolean_testable.h"          }
+      module class_or_enum              { private header "__concepts/class_or_enum.h"             }
+      module common_reference_with      { private header "__concepts/common_reference_with.h"     }
+      module common_with                { private header "__concepts/common_with.h"               }
+      module constructible              { private header "__concepts/constructible.h"             }
+      module convertible_to             { private header "__concepts/convertible_to.h"            }
+      module copyable                   { private header "__concepts/copyable.h"                  }
+      module derived_from               { private header "__concepts/derived_from.h"              }
+      module destructible               { private header "__concepts/destructible.h"              }
+      module different_from             { private header "__concepts/different_from.h"            }
+      module equality_comparable        { private header "__concepts/equality_comparable.h"       }
+      module invocable                  { private header "__concepts/invocable.h"                 }
+      module movable                    { private header "__concepts/movable.h"                   }
+      module predicate                  { private header "__concepts/predicate.h"                 }
+      module regular                    { private header "__concepts/regular.h"                   }
+      module relation                   { private header "__concepts/relation.h"                  }
+      module same_as                    { private header "__concepts/same_as.h"                   }
+      module semiregular                { private header "__concepts/semiregular.h"               }
+      module swappable                  { private header "__concepts/swappable.h"                 }
+      module totally_ordered            { private header "__concepts/totally_ordered.h"           }
+    }
+  }
+  module condition_variable {
+    header "condition_variable"
+    export *
+  }
+  module deque {
+    header "deque"
+    export initializer_list
+    export *
+  }
+  module exception {
+    header "exception"
+    export *
+  }
+  module execution {
+    header "execution"
+    export *
+  }
+  module filesystem {
+    header "filesystem"
+    export *
+  }
+  module format {
+    header "format"
+    export *
+
+    module __format {
+      module format_arg             { private header "__format/format_arg.h"           }
+      module format_args            { private header "__format/format_args.h"          }
+      module format_context {
+        private header "__format/format_context.h"
+        export optional
+        export locale
+      }
+      module format_error           { private header "__format/format_error.h"           }
+      module format_fwd             { private header "__format/format_fwd.h"             }
+      module format_parse_context   { private header "__format/format_parse_context.h"   }
+      module format_string          { private header "__format/format_string.h"          }
+      module formatter              { private header "__format/formatter.h"              }
+      module formatter_bool         { private header "__format/formatter_bool.h"         }
+      module formatter_char         { private header "__format/formatter_char.h"         }
+      module formatter_integer      { private header "__format/formatter_integer.h"      }
+      module formatter_integral     { private header "__format/formatter_integral.h"     }
+      module formatter_string       { private header "__format/formatter_string.h"       }
+      module parser_std_format_spec { private header "__format/parser_std_format_spec.h" }
+    }
+  }
+  module forward_list {
+    header "forward_list"
+    export initializer_list
+    export *
+  }
+  module fstream {
+    header "fstream"
+    export *
+  }
+  module functional {
+    header "functional"
+    export *
+
+    module __functional {
+      module binary_function            { private header "__functional/binary_function.h" }
+      module binary_negate              { private header "__functional/binary_negate.h" }
+      module bind                       { private header "__functional/bind.h" }
+      module bind_back                  { private header "__functional/bind_back.h" }
+      module bind_front                 { private header "__functional/bind_front.h" }
+      module binder1st                  { private header "__functional/binder1st.h" }
+      module binder2nd                  { private header "__functional/binder2nd.h" }
+      module compose                    { private header "__functional/compose.h" }
+      module default_searcher           { private header "__functional/default_searcher.h" }
+      module function                   { private header "__functional/function.h" }
+      module hash                       { private header "__functional/hash.h" }
+      module identity                   { private header "__functional/identity.h" }
+      module invoke                     { private header "__functional/invoke.h" }
+      module is_transparent             { private header "__functional/is_transparent.h" }
+      module mem_fn                     { private header "__functional/mem_fn.h"  }
+      module mem_fun_ref                { private header "__functional/mem_fun_ref.h"  }
+      module not_fn                     { private header "__functional/not_fn.h" }
+      module operations                 { private header "__functional/operations.h" }
+      module perfect_forward            { private header "__functional/perfect_forward.h" }
+      module pointer_to_binary_function { private header "__functional/pointer_to_binary_function.h" }
+      module pointer_to_unary_function  { private header "__functional/pointer_to_unary_function.h" }
+      module ranges_operations          { private header "__functional/ranges_operations.h" }
+      module reference_wrapper          { private header "__functional/reference_wrapper.h" }
+      module unary_function             { private header "__functional/unary_function.h" }
+      module unary_negate               { private header "__functional/unary_negate.h" }
+      module unwrap_ref                 { private header "__functional/unwrap_ref.h" }
+      module weak_result_type           { private header "__functional/weak_result_type.h" }
+    }
+  }
+  module future {
+    header "future"
+    export *
+  }
+  module initializer_list {
+    header "initializer_list"
+    export *
+  }
+  module iomanip {
+    header "iomanip"
+    export *
+  }
+  module ios {
+    header "ios"
+    export iosfwd
+    export *
+  }
+  module iosfwd {
+    header "iosfwd"
+    export *
+  }
+  module iostream {
+    header "iostream"
+    export ios
+    export streambuf
+    export istream
+    export ostream
+    export *
+  }
+  module istream {
+    header "istream"
+    // FIXME: should re-export ios, streambuf?
+    export *
+  }
+  module iterator {
+    header "iterator"
+    export *
+
+    module __iterator {
+      module access                { private header "__iterator/access.h" }
+      module advance               {
+        private header "__iterator/advance.h"
+        export __function_like
+      }
+      module back_insert_iterator  { private header "__iterator/back_insert_iterator.h" }
+      module common_iterator       { private header "__iterator/common_iterator.h" }
+      module concepts              { private header "__iterator/concepts.h" }
+      module counted_iterator      { private header "__iterator/counted_iterator.h" }
+      module data                  { private header "__iterator/data.h" }
+      module default_sentinel      { private header "__iterator/default_sentinel.h" }
+      module distance              { private header "__iterator/distance.h" }
+      module empty                 { private header "__iterator/empty.h" }
+      module erase_if_container    { private header "__iterator/erase_if_container.h" }
+      module front_insert_iterator { private header "__iterator/front_insert_iterator.h" }
+      module incrementable_traits  { private header "__iterator/incrementable_traits.h" }
+      module insert_iterator       { private header "__iterator/insert_iterator.h" }
+      module istream_iterator      { private header "__iterator/istream_iterator.h" }
+      module istreambuf_iterator   { private header "__iterator/istreambuf_iterator.h" }
+      module iter_move             { private header "__iterator/iter_move.h" }
+      module iter_swap             { private header "__iterator/iter_swap.h" }
+      module iterator              { private header "__iterator/iterator.h" }
+      module iterator_traits       { private header "__iterator/iterator_traits.h" }
+      module move_iterator         { private header "__iterator/move_iterator.h" }
+      module next                  {
+        private header "__iterator/next.h"
+        export __function_like
+      }
+      module ostream_iterator      { private header "__iterator/ostream_iterator.h" }
+      module ostreambuf_iterator   { private header "__iterator/ostreambuf_iterator.h" }
+      module prev                  {
+        private header "__iterator/prev.h"
+        export __function_like
+      }
+      module projected             { private header "__iterator/projected.h" }
+      module readable_traits       { private header "__iterator/readable_traits.h" }
+      module reverse_access        { private header "__iterator/reverse_access.h" }
+      module reverse_iterator      { private header "__iterator/reverse_iterator.h" }
+      module size                  { private header "__iterator/size.h" }
+      module unreachable_sentinel  { private header "__iterator/unreachable_sentinel.h" }
+      module wrap_iter             { private header "__iterator/wrap_iter.h" }
+    }
+  }
+  module latch {
+    requires cplusplus14
+    header "latch"
+    export *
+  }
+  module limits {
+    header "limits"
+    export *
+  }
+  module list {
+    header "list"
+    export initializer_list
+    export *
+  }
+  module locale {
+    header "locale"
+    export *
+  }
+  module map {
+    header "map"
+    export initializer_list
+    export *
+  }
+  module memory {
+    header "memory"
+    export *
+
+    module __memory {
+      module addressof                { private header "__memory/addressof.h"                }
+      module allocation_guard         { private header "__memory/allocation_guard.h"         }
+      module allocator                { private header "__memory/allocator.h"                }
+      module allocator_arg_t          { private header "__memory/allocator_arg_t.h"          }
+      module allocator_traits         { private header "__memory/allocator_traits.h"         }
+      module auto_ptr                 { private header "__memory/auto_ptr.h"                 }
+      module compressed_pair          { private header "__memory/compressed_pair.h"          }
+      module construct_at             { private header "__memory/construct_at.h"             }
+      module pointer_safety           { private header "__memory/pointer_safety.h"           }
+      module pointer_traits           { private header "__memory/pointer_traits.h"           }
+      module raw_storage_iterator     { private header "__memory/raw_storage_iterator.h"     }
+      module shared_ptr               { private header "__memory/shared_ptr.h"               }
+      module temporary_buffer         { private header "__memory/temporary_buffer.h"         }
+      module uninitialized_algorithms { private header "__memory/uninitialized_algorithms.h" }
+      module unique_ptr               { private header "__memory/unique_ptr.h"               }
+      module uses_allocator           { private header "__memory/uses_allocator.h"           }
+    }
+  }
+  module mutex {
+    header "mutex"
+    export *
+  }
+  module new {
+    header "new"
+    export *
+  }
+  module numbers {
+    header "numbers"
+    export *
+  }
+  module numeric {
+    header "numeric"
+    export *
+  }
+  module optional {
+    header "optional"
+    export *
+  }
+  module ostream {
+    header "ostream"
+    // FIXME: should re-export ios, streambuf?
+    export *
+  }
+  module queue {
+    header "queue"
+    export initializer_list
+    export *
+  }
+  module random {
+    header "random"
+    export initializer_list
+    export *
+
+    module __random {
+      module uniform_int_distribution { private header "__random/uniform_int_distribution.h" }
+    }
+  }
+  module ranges {
+    header "ranges"
+    export compare
+    export initializer_list
+    export iterator
+    export *
+
+    module __ranges {
+      module access                 { private header "__ranges/access.h"                }
+      module all                    {
+        private header "__ranges/all.h"
+        export functional.__functional.compose
+        export functional.__functional.perfect_forward
+      }
+      module common_view            { private header "__ranges/common_view.h"           }
+      module concepts               { private header "__ranges/concepts.h"              }
+      module copyable_box           { private header "__ranges/copyable_box.h"          }
+      module counted                { private header "__ranges/counted.h"               }
+      module dangling               { private header "__ranges/dangling.h"              }
+      module data                   { private header "__ranges/data.h"                  }
+      module drop_view              { private header "__ranges/drop_view.h"             }
+      module empty                  { private header "__ranges/empty.h"                 }
+      module empty_view             { private header "__ranges/empty_view.h"            }
+      module enable_borrowed_range  { private header "__ranges/enable_borrowed_range.h" }
+      module enable_view            { private header "__ranges/enable_view.h"           }
+      module iota_view              { private header "__ranges/iota_view.h"             }
+      module join_view              { private header "__ranges/join_view.h"             }
+      module non_propagating_cache  { private header "__ranges/non_propagating_cache.h" }
+      module range_adaptor          { private header "__ranges/range_adaptor.h"         }
+      module ref_view               { private header "__ranges/ref_view.h"              }
+      module reverse_view           { private header "__ranges/reverse_view.h"          }
+      module size                   { private header "__ranges/size.h"                  }
+      module single_view            { private header "__ranges/single_view.h"           }
+      module subrange               { private header "__ranges/subrange.h"              }
+      module take_view              { private header "__ranges/take_view.h"             }
+      module transform_view         {
+        private header "__ranges/transform_view.h"
+        export functional.__functional.bind_back
+        export functional.__functional.perfect_forward
+      }
+      module view_interface         { private header "__ranges/view_interface.h"        }
+    }
+  }
+  module ratio {
+    header "ratio"
+    export *
+  }
+  module regex {
+    header "regex"
+    export initializer_list
+    export *
+  }
+  module scoped_allocator {
+    header "scoped_allocator"
+    export *
+  }
+  module semaphore {
+    requires cplusplus14
+    header "semaphore"
+    export *
+  }
+  module set {
+    header "set"
+    export initializer_list
+    export *
+  }
+  module shared_mutex {
+    header "shared_mutex"
+    export version
+  }
+  module span {
+    header "span"
+    export ranges.__ranges.enable_borrowed_range
+    export version
+  }
+  module sstream {
+    header "sstream"
+    // FIXME: should re-export istream, ostream, ios, streambuf, string?
+    export *
+  }
+  module stack {
+    header "stack"
+    export initializer_list
+    export *
+  }
+  module stdexcept {
+    header "stdexcept"
+    export *
+  }
+  module streambuf {
+    header "streambuf"
+    export *
+  }
+  module string {
+    header "string"
+    export initializer_list
+    export string_view
+    export __string
+    export *
+  }
+  module string_view {
+    header "string_view"
+    export initializer_list
+    export __string
+    export *
+  }
+  module strstream {
+    header "strstream"
+    export *
+  }
+  module system_error {
+    header "system_error"
+    export *
+  }
+  module thread {
+    header "thread"
+    export *
+  }
+  module tuple {
+    header "tuple"
+    export *
+  }
+  module type_traits {
+    header "type_traits"
+    export functional.__functional.unwrap_ref
+    export *
+  }
+  module typeindex {
+    header "typeindex"
+    export *
+  }
+  module typeinfo {
+    header "typeinfo"
+    export *
+  }
+  module unordered_map {
+    header "unordered_map"
+    export initializer_list
+    export *
+  }
+  module unordered_set {
+    header "unordered_set"
+    export initializer_list
+    export *
+  }
+  module utility {
+    header "utility"
+    export initializer_list
+    export *
+
+    module __utility {
+      module as_const            { private header "__utility/as_const.h"            }
+      module cmp                 { private header "__utility/cmp.h"                 }
+      module decay_copy          { private header "__utility/decay_copy.h"          }
+      module declval             { private header "__utility/declval.h"             }
+      module exchange            { private header "__utility/exchange.h"            }
+      module forward             { private header "__utility/forward.h"             }
+      module in_place            { private header "__utility/in_place.h"            }
+      module integer_sequence    { private header "__utility/integer_sequence.h"    }
+      module move                { private header "__utility/move.h"                }
+      module pair                { private header "__utility/pair.h"                }
+      module piecewise_construct { private header "__utility/piecewise_construct.h" }
+      module rel_ops             { private header "__utility/rel_ops.h"             }
+      module swap                { private header "__utility/swap.h"                }
+      module to_underlying       { private header "__utility/to_underlying.h"       }
+    }
+  }
+  module valarray {
+    header "valarray"
+    export initializer_list
+    export *
+  }
+  module variant {
+    header "variant"
+    export *
+
+    module __variant {
+      module monostate { private header "__variant/monostate.h" }
+    }
+  }
+  module vector {
+    header "vector"
+    export initializer_list
+    export *
+  }
+  module version {
+    header "version"
+    export *
+  }
+
+  // __config not modularised due to a bug in Clang
+  // FIXME: These should be private.
+  module __availability      { private header "__availability"      export * }
+  module __bit_reference     { private header "__bit_reference"     export * }
+  module __bits              { private header "__bits"              export * }
+  module __debug             { header "__debug"             export * }
+  module __errc              { private header "__errc"              export * }
+  module __function_like     { private header "__function_like.h"   export * }
+  module __hash_table        { header "__hash_table"        export * }
+  module __locale            { private header "__locale"            export * }
+  module __mbstate           { private header "__mbstate_t.h"       export * }
+  module __mutex_base        { private header "__mutex_base"        export * }
+  module __node_handle       { private header "__node_handle"       export * }
+  module __nullptr           { header "__nullptr"           export * }
+  module __split_buffer      { private header "__split_buffer"      export * }
+  module __std_stream        { private header "__std_stream"        export * }
+  module __string            { private header "__string"            export * }
+  module __threading_support { header "__threading_support" export * }
+  module __tree              { header "__tree"              export * }
+  module __tuple             { private header "__tuple"             export * }
+  module __undef_macros      { header "__undef_macros"      export * }
+
+  module experimental {
+    requires cplusplus11
+
+    module algorithm {
+      header "experimental/algorithm"
+      export *
+    }
+     module coroutine {
+      requires coroutines
+      header "experimental/coroutine"
+      export *
+    }
+    module deque {
+      header "experimental/deque"
+      export *
+    }
+    module filesystem {
+      header "experimental/filesystem"
+      export *
+    }
+    module forward_list {
+      header "experimental/forward_list"
+      export *
+    }
+    module functional {
+      header "experimental/functional"
+      export *
+    }
+    module iterator {
+      header "experimental/iterator"
+      export *
+    }
+    module list {
+      header "experimental/list"
+      export *
+    }
+    module map {
+      header "experimental/map"
+      export *
+    }
+    module memory_resource {
+      header "experimental/memory_resource"
+      export *
+    }
+    module propagate_const {
+      header "experimental/propagate_const"
+      export *
+    }
+    module regex {
+      header "experimental/regex"
+      export *
+    }
+    module simd {
+      header "experimental/simd"
+      export *
+    }
+    module set {
+      header "experimental/set"
+      export *
+    }
+    module span {
+      header "span"
+      export *
+    }
+    module string {
+      header "experimental/string"
+      export *
+    }
+    module type_traits {
+      header "experimental/type_traits"
+      export *
+    }
+    module unordered_map {
+      header "experimental/unordered_map"
+      export *
+    }
+    module unordered_set {
+      header "experimental/unordered_set"
+      export *
+    }
+    module utility {
+      header "experimental/utility"
+      export *
+    }
+    module vector {
+      header "experimental/vector"
+      export *
+    }
+    // FIXME these should be private
+    module __memory {
+      header "experimental/__memory"
+      export *
+    }
+  } // end experimental
+}
diff --git a/contrib/libs/cxxsupp/libcxx/include/mutex b/contrib/libs/cxxsupp/libcxx/include/mutex
new file mode 100644
index 00000000000..e815dda5021
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/mutex
@@ -0,0 +1,737 @@
+// -*- C++ -*-
+//===--------------------------- mutex ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_MUTEX
+#define _LIBCPP_MUTEX
+
+/*
+    mutex synopsis
+
+namespace std
+{
+
+class mutex
+{
+public:
+     constexpr mutex() noexcept;
+     ~mutex();
+
+    mutex(const mutex&) = delete;
+    mutex& operator=(const mutex&) = delete;
+
+    void lock();
+    bool try_lock();
+    void unlock();
+
+    typedef pthread_mutex_t* native_handle_type;
+    native_handle_type native_handle();
+};
+
+class recursive_mutex
+{
+public:
+     recursive_mutex();
+     ~recursive_mutex();
+
+    recursive_mutex(const recursive_mutex&) = delete;
+    recursive_mutex& operator=(const recursive_mutex&) = delete;
+
+    void lock();
+    bool try_lock() noexcept;
+    void unlock();
+
+    typedef pthread_mutex_t* native_handle_type;
+    native_handle_type native_handle();
+};
+
+class timed_mutex
+{
+public:
+     timed_mutex();
+     ~timed_mutex();
+
+    timed_mutex(const timed_mutex&) = delete;
+    timed_mutex& operator=(const timed_mutex&) = delete;
+
+    void lock();
+    bool try_lock();
+    template <class Rep, class Period>
+        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
+    template <class Clock, class Duration>
+        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
+    void unlock();
+};
+
+class recursive_timed_mutex
+{
+public:
+     recursive_timed_mutex();
+     ~recursive_timed_mutex();
+
+    recursive_timed_mutex(const recursive_timed_mutex&) = delete;
+    recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete;
+
+    void lock();
+    bool try_lock() noexcept;
+    template <class Rep, class Period>
+        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
+    template <class Clock, class Duration>
+        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
+    void unlock();
+};
+
+struct defer_lock_t { explicit defer_lock_t() = default; };
+struct try_to_lock_t { explicit try_to_lock_t() = default; };
+struct adopt_lock_t { explicit adopt_lock_t() = default; };
+
+inline constexpr defer_lock_t  defer_lock{};
+inline constexpr try_to_lock_t try_to_lock{};
+inline constexpr adopt_lock_t  adopt_lock{};
+
+template <class Mutex>
+class lock_guard
+{
+public:
+    typedef Mutex mutex_type;
+
+    explicit lock_guard(mutex_type& m);
+    lock_guard(mutex_type& m, adopt_lock_t);
+    ~lock_guard();
+
+    lock_guard(lock_guard const&) = delete;
+    lock_guard& operator=(lock_guard const&) = delete;
+};
+
+template <class... MutexTypes>
+class scoped_lock // C++17
+{
+public:
+    using mutex_type = Mutex;  // If MutexTypes... consists of the single type Mutex
+
+    explicit scoped_lock(MutexTypes&... m);
+    scoped_lock(adopt_lock_t, MutexTypes&... m);
+    ~scoped_lock();
+    scoped_lock(scoped_lock const&) = delete;
+    scoped_lock& operator=(scoped_lock const&) = delete;
+private:
+    tuple<MutexTypes&...> pm; // exposition only
+};
+
+template <class Mutex>
+class unique_lock
+{
+public:
+    typedef Mutex mutex_type;
+    unique_lock() noexcept;
+    explicit unique_lock(mutex_type& m);
+    unique_lock(mutex_type& m, defer_lock_t) noexcept;
+    unique_lock(mutex_type& m, try_to_lock_t);
+    unique_lock(mutex_type& m, adopt_lock_t);
+    template <class Clock, class Duration>
+        unique_lock(mutex_type& m, const chrono::time_point<Clock, Duration>& abs_time);
+    template <class Rep, class Period>
+        unique_lock(mutex_type& m, const chrono::duration<Rep, Period>& rel_time);
+    ~unique_lock();
+
+    unique_lock(unique_lock const&) = delete;
+    unique_lock& operator=(unique_lock const&) = delete;
+
+    unique_lock(unique_lock&& u) noexcept;
+    unique_lock& operator=(unique_lock&& u) noexcept;
+
+    void lock();
+    bool try_lock();
+
+    template <class Rep, class Period>
+        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
+    template <class Clock, class Duration>
+        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
+
+    void unlock();
+
+    void swap(unique_lock& u) noexcept;
+    mutex_type* release() noexcept;
+
+    bool owns_lock() const noexcept;
+    explicit operator bool () const noexcept;
+    mutex_type* mutex() const noexcept;
+};
+
+template <class Mutex>
+  void swap(unique_lock<Mutex>& x, unique_lock<Mutex>& y) noexcept;
+
+template <class L1, class L2, class... L3>
+  int try_lock(L1&, L2&, L3&...);
+template <class L1, class L2, class... L3>
+  void lock(L1&, L2&, L3&...);
+
+struct once_flag
+{
+    constexpr once_flag() noexcept;
+
+    once_flag(const once_flag&) = delete;
+    once_flag& operator=(const once_flag&) = delete;
+};
+
+template<class Callable, class ...Args>
+  void call_once(once_flag& flag, Callable&& func, Args&&... args);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__mutex_base>
+#include <__threading_support>
+#include <__utility/forward.h>
+#include <cstdint>
+#include <functional>
+#include <memory>
+#ifndef _LIBCPP_CXX03_LANG
+# include <tuple>
+#endif
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_CXX03_LANG)
+#include <atomic>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+
+class _LIBCPP_TYPE_VIS recursive_mutex
+{
+    __libcpp_recursive_mutex_t __m_;
+
+public:
+     recursive_mutex();
+     ~recursive_mutex();
+
+private:
+    recursive_mutex(const recursive_mutex&); // = delete;
+    recursive_mutex& operator=(const recursive_mutex&); // = delete;
+
+public:
+    void lock();
+    bool try_lock() _NOEXCEPT;
+    void unlock()  _NOEXCEPT;
+
+    typedef __libcpp_recursive_mutex_t* native_handle_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    native_handle_type native_handle() {return &__m_;}
+};
+
+class _LIBCPP_TYPE_VIS timed_mutex
+{
+    mutex              __m_;
+    condition_variable __cv_;
+    bool               __locked_;
+public:
+     timed_mutex();
+     ~timed_mutex();
+
+private:
+    timed_mutex(const timed_mutex&); // = delete;
+    timed_mutex& operator=(const timed_mutex&); // = delete;
+
+public:
+    void lock();
+    bool try_lock() _NOEXCEPT;
+    template <class _Rep, class _Period>
+        _LIBCPP_INLINE_VISIBILITY
+        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
+            {return try_lock_until(chrono::steady_clock::now() + __d);}
+    template <class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
+    void unlock() _NOEXCEPT;
+};
+
+template <class _Clock, class _Duration>
+bool
+timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
+{
+    using namespace chrono;
+    unique_lock<mutex> __lk(__m_);
+    bool no_timeout = _Clock::now() < __t;
+    while (no_timeout && __locked_)
+        no_timeout = __cv_.wait_until(__lk, __t) == cv_status::no_timeout;
+    if (!__locked_)
+    {
+        __locked_ = true;
+        return true;
+    }
+    return false;
+}
+
+class _LIBCPP_TYPE_VIS recursive_timed_mutex
+{
+    mutex              __m_;
+    condition_variable __cv_;
+    size_t             __count_;
+    __thread_id        __id_;
+public:
+     recursive_timed_mutex();
+     ~recursive_timed_mutex();
+
+private:
+    recursive_timed_mutex(const recursive_timed_mutex&); // = delete;
+    recursive_timed_mutex& operator=(const recursive_timed_mutex&); // = delete;
+
+public:
+    void lock();
+    bool try_lock() _NOEXCEPT;
+    template <class _Rep, class _Period>
+        _LIBCPP_INLINE_VISIBILITY
+        bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
+            {return try_lock_until(chrono::steady_clock::now() + __d);}
+    template <class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
+    void unlock() _NOEXCEPT;
+};
+
+template <class _Clock, class _Duration>
+bool
+recursive_timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
+{
+    using namespace chrono;
+    __thread_id __id = this_thread::get_id();
+    unique_lock<mutex> lk(__m_);
+    if (__id == __id_)
+    {
+        if (__count_ == numeric_limits<size_t>::max())
+            return false;
+        ++__count_;
+        return true;
+    }
+    bool no_timeout = _Clock::now() < __t;
+    while (no_timeout && __count_ != 0)
+        no_timeout = __cv_.wait_until(lk, __t) == cv_status::no_timeout;
+    if (__count_ == 0)
+    {
+        __count_ = 1;
+        __id_ = __id;
+        return true;
+    }
+    return false;
+}
+
+template <class _L0, class _L1>
+int
+try_lock(_L0& __l0, _L1& __l1)
+{
+    unique_lock<_L0> __u0(__l0, try_to_lock);
+    if (__u0.owns_lock())
+    {
+        if (__l1.try_lock())
+        {
+            __u0.release();
+            return -1;
+        }
+        else
+            return 1;
+    }
+    return 0;
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _L0, class _L1, class _L2, class... _L3>
+int
+try_lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3)
+{
+    int __r = 0;
+    unique_lock<_L0> __u0(__l0, try_to_lock);
+    if (__u0.owns_lock())
+    {
+        __r = try_lock(__l1, __l2, __l3...);
+        if (__r == -1)
+            __u0.release();
+        else
+            ++__r;
+    }
+    return __r;
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _L0, class _L1>
+void
+lock(_L0& __l0, _L1& __l1)
+{
+    while (true)
+    {
+        {
+            unique_lock<_L0> __u0(__l0);
+            if (__l1.try_lock())
+            {
+                __u0.release();
+                break;
+            }
+        }
+        __libcpp_thread_yield();
+        {
+            unique_lock<_L1> __u1(__l1);
+            if (__l0.try_lock())
+            {
+                __u1.release();
+                break;
+            }
+        }
+        __libcpp_thread_yield();
+    }
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _L0, class _L1, class _L2, class ..._L3>
+void
+__lock_first(int __i, _L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
+{
+    while (true)
+    {
+        switch (__i)
+        {
+        case 0:
+            {
+                unique_lock<_L0> __u0(__l0);
+                __i = try_lock(__l1, __l2, __l3...);
+                if (__i == -1)
+                {
+                    __u0.release();
+                    return;
+                }
+            }
+            ++__i;
+            __libcpp_thread_yield();
+            break;
+        case 1:
+            {
+                unique_lock<_L1> __u1(__l1);
+                __i = try_lock(__l2, __l3..., __l0);
+                if (__i == -1)
+                {
+                    __u1.release();
+                    return;
+                }
+            }
+            if (__i == sizeof...(_L3) + 1)
+                __i = 0;
+            else
+                __i += 2;
+            __libcpp_thread_yield();
+            break;
+        default:
+            __lock_first(__i - 2, __l2, __l3..., __l0, __l1);
+            return;
+        }
+    }
+}
+
+template <class _L0, class _L1, class _L2, class ..._L3>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+lock(_L0& __l0, _L1& __l1, _L2& __l2, _L3& ...__l3)
+{
+    __lock_first(0, __l0, __l1, __l2, __l3...);
+}
+
+template <class _L0>
+inline _LIBCPP_INLINE_VISIBILITY
+void __unlock(_L0& __l0) {
+    __l0.unlock();
+}
+
+template <class _L0, class _L1>
+inline _LIBCPP_INLINE_VISIBILITY
+void __unlock(_L0& __l0, _L1& __l1) {
+    __l0.unlock();
+    __l1.unlock();
+}
+
+template <class _L0, class _L1, class _L2, class ..._L3>
+inline _LIBCPP_INLINE_VISIBILITY
+void __unlock(_L0& __l0, _L1& __l1, _L2& __l2, _L3&... __l3) {
+    __l0.unlock();
+    __l1.unlock();
+    _VSTD::__unlock(__l2, __l3...);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+#if _LIBCPP_STD_VER > 14
+template <class ..._Mutexes>
+class _LIBCPP_TEMPLATE_VIS scoped_lock;
+
+template <>
+class _LIBCPP_TEMPLATE_VIS scoped_lock<> {
+public:
+    explicit scoped_lock() {}
+    ~scoped_lock() = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit scoped_lock(adopt_lock_t) {}
+
+    scoped_lock(scoped_lock const&) = delete;
+    scoped_lock& operator=(scoped_lock const&) = delete;
+};
+
+template <class _Mutex>
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_THREAD_SAFETY_ANNOTATION(scoped_lockable) scoped_lock<_Mutex> {
+public:
+    typedef _Mutex  mutex_type;
+private:
+    mutex_type& __m_;
+public:
+    explicit scoped_lock(mutex_type & __m) _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability(__m))
+        : __m_(__m) {__m_.lock();}
+
+    ~scoped_lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(release_capability()) {__m_.unlock();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit scoped_lock(adopt_lock_t, mutex_type& __m) _LIBCPP_THREAD_SAFETY_ANNOTATION(requires_capability(__m))
+        : __m_(__m) {}
+
+    scoped_lock(scoped_lock const&) = delete;
+    scoped_lock& operator=(scoped_lock const&) = delete;
+};
+
+template <class ..._MArgs>
+class _LIBCPP_TEMPLATE_VIS scoped_lock
+{
+    static_assert(sizeof...(_MArgs) > 1, "At least 2 lock types required");
+    typedef tuple<_MArgs&...> _MutexTuple;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit scoped_lock(_MArgs&... __margs)
+      : __t_(__margs...)
+    {
+        _VSTD::lock(__margs...);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    scoped_lock(adopt_lock_t, _MArgs&... __margs)
+        : __t_(__margs...)
+    {
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~scoped_lock() {
+        typedef typename __make_tuple_indices<sizeof...(_MArgs)>::type _Indices;
+        __unlock_unpack(_Indices{}, __t_);
+    }
+
+    scoped_lock(scoped_lock const&) = delete;
+    scoped_lock& operator=(scoped_lock const&) = delete;
+
+private:
+    template <size_t ..._Indx>
+    _LIBCPP_INLINE_VISIBILITY
+    static void __unlock_unpack(__tuple_indices<_Indx...>, _MutexTuple& __mt) {
+        _VSTD::__unlock(_VSTD::get<_Indx>(__mt)...);
+    }
+
+    _MutexTuple __t_;
+};
+
+#endif // _LIBCPP_STD_VER > 14
+#endif // !_LIBCPP_HAS_NO_THREADS
+
+struct _LIBCPP_TEMPLATE_VIS once_flag;
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _Callable, class... _Args>
+_LIBCPP_INLINE_VISIBILITY
+void call_once(once_flag&, _Callable&&, _Args&&...);
+
+#else  // _LIBCPP_CXX03_LANG
+
+template<class _Callable>
+_LIBCPP_INLINE_VISIBILITY
+void call_once(once_flag&, _Callable&);
+
+template<class _Callable>
+_LIBCPP_INLINE_VISIBILITY
+void call_once(once_flag&, const _Callable&);
+
+#endif // _LIBCPP_CXX03_LANG
+
+struct _LIBCPP_TEMPLATE_VIS once_flag
+{
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR
+        once_flag() _NOEXCEPT : __state_(0) {}
+
+#if defined(_LIBCPP_ABI_MICROSOFT)
+   typedef uintptr_t _State_type;
+#else
+   typedef unsigned long _State_type;
+#endif
+
+
+private:
+    once_flag(const once_flag&); // = delete;
+    once_flag& operator=(const once_flag&); // = delete;
+
+#if defined(_LIBCPP_ABI_MICROSOFT)
+    atomic<_State_type> __state_;
+#else
+    _State_type __state_;
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+    template<class _Callable, class... _Args>
+    friend
+    void call_once(once_flag&, _Callable&&, _Args&&...);
+#else  // _LIBCPP_CXX03_LANG
+    template<class _Callable>
+    friend
+    void call_once(once_flag&, _Callable&);
+
+    template<class _Callable>
+    friend
+    void call_once(once_flag&, const _Callable&);
+#endif // _LIBCPP_CXX03_LANG
+};
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Fp>
+class __call_once_param
+{
+    _Fp& __f_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __call_once_param(_Fp& __f) : __f_(__f) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator()()
+    {
+        typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
+        __execute(_Index());
+    }
+
+private:
+    template <size_t ..._Indices>
+    _LIBCPP_INLINE_VISIBILITY
+    void __execute(__tuple_indices<_Indices...>)
+    {
+        _VSTD::__invoke(_VSTD::get<0>(_VSTD::move(__f_)), _VSTD::get<_Indices>(_VSTD::move(__f_))...);
+    }
+};
+
+#else
+
+template <class _Fp>
+class __call_once_param
+{
+    _Fp& __f_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __call_once_param(_Fp& __f) : __f_(__f) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator()()
+    {
+        __f_();
+    }
+};
+
+#endif
+
+template <class _Fp>
+void _LIBCPP_INLINE_VISIBILITY
+__call_once_proxy(void* __vp)
+{
+    __call_once_param<_Fp>* __p = static_cast<__call_once_param<_Fp>*>(__vp);
+    (*__p)();
+}
+
+#ifdef _LIBCPP_ABI_MICROSOFT
+_LIBCPP_FUNC_VIS void __call_once(volatile atomic<once_flag::_State_type>&, void*,
+                                  void (*)(void*));
+#else
+_LIBCPP_FUNC_VIS void __call_once(volatile once_flag::_State_type&, void*,
+                                  void (*)(void*));
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _Callable, class... _Args>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args)
+{
+#if defined(_LIBCPP_ABI_MICROSOFT)
+    if (__flag.__state_.load(memory_order_acquire) != ~once_flag::_State_type(0))
+#else
+    if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
+#endif
+    {
+        typedef tuple<_Callable&&, _Args&&...> _Gp;
+        _Gp __f(_VSTD::forward<_Callable>(__func), _VSTD::forward<_Args>(__args)...);
+        __call_once_param<_Gp> __p(__f);
+        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Gp>);
+    }
+}
+
+#else  // _LIBCPP_CXX03_LANG
+
+template<class _Callable>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+call_once(once_flag& __flag, _Callable& __func)
+{
+#if defined(_LIBCPP_ABI_MICROSOFT)
+    if (__flag.__state_.load(memory_order_acquire) != ~once_flag::_State_type(0))
+#else
+    if (__libcpp_acquire_load(&__flag.__state_) != ~once_flag::_State_type(0))
+#endif
+    {
+        __call_once_param<_Callable> __p(__func);
+        __call_once(__flag.__state_, &__p, &__call_once_proxy<_Callable>);
+    }
+}
+
+template<class _Callable>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+call_once(once_flag& __flag, const _Callable& __func)
+{
+#if defined(_LIBCPP_ABI_MICROSOFT)
+    if (__flag.__state_.load(memory_order_relaxed) != ~once_flag::_State_type(0))
+#else
+    if (__flag.__state_ != ~once_flag::_State_type(0))
+#endif
+    {
+        __call_once_param<const _Callable> __p(__func);
+        __call_once(__flag.__state_, &__p, &__call_once_proxy<const _Callable>);
+    }
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_MUTEX
diff --git a/contrib/libs/cxxsupp/libcxx/include/new b/contrib/libs/cxxsupp/libcxx/include/new
new file mode 100644
index 00000000000..2d1417a9758
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/new
@@ -0,0 +1,354 @@
+// -*- C++ -*-
+//===----------------------------- new ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_NEW
+#define _LIBCPP_NEW
+
+/*
+    new synopsis
+
+namespace std
+{
+
+class bad_alloc
+    : public exception
+{
+public:
+    bad_alloc() noexcept;
+    bad_alloc(const bad_alloc&) noexcept;
+    bad_alloc& operator=(const bad_alloc&) noexcept;
+    virtual const char* what() const noexcept;
+};
+
+class bad_array_new_length : public bad_alloc // C++14
+{
+public:
+    bad_array_new_length() noexcept;
+};
+
+enum class align_val_t : size_t {}; // C++17
+
+struct destroying_delete_t { // C++20
+  explicit destroying_delete_t() = default;
+};
+inline constexpr destroying_delete_t destroying_delete{}; // C++20
+
+struct nothrow_t { explicit nothrow_t() = default; };
+extern const nothrow_t nothrow;
+typedef void (*new_handler)();
+new_handler set_new_handler(new_handler new_p) noexcept;
+new_handler get_new_handler() noexcept;
+
+// 21.6.4, pointer optimization barrier
+template <class T> constexpr T* launder(T* p) noexcept; // C++17
+}  // std
+
+void* operator new(std::size_t size);                                   // replaceable, nodiscard in C++20
+void* operator new(std::size_t size, std::align_val_t alignment);       // replaceable, C++17, nodiscard in C++20
+void* operator new(std::size_t size, const std::nothrow_t&) noexcept;   // replaceable, nodiscard in C++20
+void* operator new(std::size_t size, std::align_val_t alignment,
+                   const std::nothrow_t&) noexcept;                     // replaceable, C++17, nodiscard in C++20
+void  operator delete(void* ptr) noexcept;                              // replaceable
+void  operator delete(void* ptr, std::size_t size) noexcept;            // replaceable, C++14
+void  operator delete(void* ptr, std::align_val_t alignment) noexcept;  // replaceable, C++17
+void  operator delete(void* ptr, std::size_t size,
+                      std::align_val_t alignment) noexcept;             // replaceable, C++17
+void  operator delete(void* ptr, const std::nothrow_t&) noexcept;       // replaceable
+void  operator delete(void* ptr, std:align_val_t alignment,
+                      const std::nothrow_t&) noexcept;                  // replaceable, C++17
+
+void* operator new[](std::size_t size);                                 // replaceable, nodiscard in C++20
+void* operator new[](std::size_t size,
+                     std::align_val_t alignment) noexcept;              // replaceable, C++17, nodiscard in C++20
+void* operator new[](std::size_t size, const std::nothrow_t&) noexcept; // replaceable, nodiscard in C++20
+void* operator new[](std::size_t size, std::align_val_t alignment,
+                     const std::nothrow_t&) noexcept;                   // replaceable, C++17, nodiscard in C++20
+void  operator delete[](void* ptr) noexcept;                            // replaceable
+void  operator delete[](void* ptr, std::size_t size) noexcept;          // replaceable, C++14
+void  operator delete[](void* ptr,
+                        std::align_val_t alignment) noexcept;           // replaceable, C++17
+void  operator delete[](void* ptr, std::size_t size,
+                        std::align_val_t alignment) noexcept;           // replaceable, C++17
+void  operator delete[](void* ptr, const std::nothrow_t&) noexcept;     // replaceable
+void  operator delete[](void* ptr, std::align_val_t alignment,
+                        const std::nothrow_t&) noexcept;                // replaceable, C++17
+
+void* operator new  (std::size_t size, void* ptr) noexcept;             // nodiscard in C++20
+void* operator new[](std::size_t size, void* ptr) noexcept;             // nodiscard in C++20
+void  operator delete  (void* ptr, void*) noexcept;
+void  operator delete[](void* ptr, void*) noexcept;
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <cstddef>
+#include <cstdlib>
+#include <exception>
+#include <type_traits>
+#include <version>
+
+#if defined(_LIBCPP_ABI_VCRUNTIME)
+#include <new.h>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#if !defined(__cpp_sized_deallocation) || __cpp_sized_deallocation  < 201309L
+#define _LIBCPP_HAS_NO_LANGUAGE_SIZED_DEALLOCATION
+#endif
+
+#if !defined(_LIBCPP_BUILDING_LIBRARY) && _LIBCPP_STD_VER < 14 && \
+    defined(_LIBCPP_HAS_NO_LANGUAGE_SIZED_DEALLOCATION)
+# define _LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION
+#endif
+
+#if defined(_LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION) || \
+    defined(_LIBCPP_HAS_NO_LANGUAGE_SIZED_DEALLOCATION)
+# define _LIBCPP_HAS_NO_SIZED_DEALLOCATION
+#endif
+
+namespace std  // purposefully not using versioning namespace
+{
+
+#if !defined(_LIBCPP_ABI_VCRUNTIME)
+struct _LIBCPP_TYPE_VIS nothrow_t { explicit nothrow_t() = default; };
+extern _LIBCPP_FUNC_VIS const nothrow_t nothrow;
+
+class _LIBCPP_EXCEPTION_ABI bad_alloc
+    : public exception
+{
+public:
+    bad_alloc() _NOEXCEPT;
+    virtual ~bad_alloc() _NOEXCEPT;
+    virtual const char* what() const _NOEXCEPT;
+};
+
+class _LIBCPP_EXCEPTION_ABI bad_array_new_length
+    : public bad_alloc
+{
+public:
+    bad_array_new_length() _NOEXCEPT;
+    virtual ~bad_array_new_length() _NOEXCEPT;
+    virtual const char* what() const _NOEXCEPT;
+};
+
+typedef void (*new_handler)();
+_LIBCPP_FUNC_VIS new_handler set_new_handler(new_handler) _NOEXCEPT;
+_LIBCPP_FUNC_VIS new_handler get_new_handler() _NOEXCEPT;
+
+#endif // !_LIBCPP_ABI_VCRUNTIME
+
+_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void __throw_bad_alloc();  // not in C++ spec
+
+#if !defined(_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION) && \
+    !defined(_LIBCPP_ABI_VCRUNTIME)
+#ifndef _LIBCPP_CXX03_LANG
+enum class _LIBCPP_ENUM_VIS align_val_t : size_t { };
+#else
+enum align_val_t { __zero = 0, __max = (size_t)-1 };
+#endif
+#endif
+
+#if _LIBCPP_STD_VER > 17
+// Enable the declaration even if the compiler doesn't support the language
+// feature.
+struct destroying_delete_t {
+  explicit destroying_delete_t() = default;
+};
+inline constexpr destroying_delete_t destroying_delete{};
+#endif // _LIBCPP_STD_VER > 17
+
+}  // std
+
+#if defined(_LIBCPP_CXX03_LANG)
+#define _THROW_BAD_ALLOC throw(std::bad_alloc)
+#else
+#define _THROW_BAD_ALLOC
+#endif
+
+#if !defined(_LIBCPP_ABI_VCRUNTIME)
+
+_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz) _THROW_BAD_ALLOC;
+_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz, const std::nothrow_t&) _NOEXCEPT _LIBCPP_NOALIAS;
+_LIBCPP_OVERRIDABLE_FUNC_VIS void  operator delete(void* __p) _NOEXCEPT;
+_LIBCPP_OVERRIDABLE_FUNC_VIS void  operator delete(void* __p, const std::nothrow_t&) _NOEXCEPT;
+#ifndef _LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION
+_LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE void  operator delete(void* __p, std::size_t __sz) _NOEXCEPT;
+#endif
+
+_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz) _THROW_BAD_ALLOC;
+_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz, const std::nothrow_t&) _NOEXCEPT _LIBCPP_NOALIAS;
+_LIBCPP_OVERRIDABLE_FUNC_VIS void  operator delete[](void* __p) _NOEXCEPT;
+_LIBCPP_OVERRIDABLE_FUNC_VIS void  operator delete[](void* __p, const std::nothrow_t&) _NOEXCEPT;
+#ifndef _LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION
+_LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE void  operator delete[](void* __p, std::size_t __sz) _NOEXCEPT;
+#endif
+
+#ifndef _LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
+_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz, std::align_val_t) _THROW_BAD_ALLOC;
+_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new(std::size_t __sz, std::align_val_t, const std::nothrow_t&) _NOEXCEPT _LIBCPP_NOALIAS;
+_LIBCPP_OVERRIDABLE_FUNC_VIS void  operator delete(void* __p, std::align_val_t) _NOEXCEPT;
+_LIBCPP_OVERRIDABLE_FUNC_VIS void  operator delete(void* __p, std::align_val_t, const std::nothrow_t&) _NOEXCEPT;
+#ifndef _LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION
+_LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE void  operator delete(void* __p, std::size_t __sz, std::align_val_t) _NOEXCEPT;
+#endif
+
+_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz, std::align_val_t) _THROW_BAD_ALLOC;
+_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_OVERRIDABLE_FUNC_VIS void* operator new[](std::size_t __sz, std::align_val_t, const std::nothrow_t&) _NOEXCEPT _LIBCPP_NOALIAS;
+_LIBCPP_OVERRIDABLE_FUNC_VIS void  operator delete[](void* __p, std::align_val_t) _NOEXCEPT;
+_LIBCPP_OVERRIDABLE_FUNC_VIS void  operator delete[](void* __p, std::align_val_t, const std::nothrow_t&) _NOEXCEPT;
+#ifndef _LIBCPP_HAS_NO_LIBRARY_SIZED_DEALLOCATION
+_LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE void  operator delete[](void* __p, std::size_t __sz, std::align_val_t) _NOEXCEPT;
+#endif
+#endif
+
+_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_INLINE_VISIBILITY void* operator new  (std::size_t, void* __p) _NOEXCEPT {return __p;}
+_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_INLINE_VISIBILITY void* operator new[](std::size_t, void* __p) _NOEXCEPT {return __p;}
+inline _LIBCPP_INLINE_VISIBILITY void  operator delete  (void*, void*) _NOEXCEPT {}
+inline _LIBCPP_INLINE_VISIBILITY void  operator delete[](void*, void*) _NOEXCEPT {}
+
+#endif // !_LIBCPP_ABI_VCRUNTIME
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+_LIBCPP_CONSTEXPR inline _LIBCPP_INLINE_VISIBILITY bool __is_overaligned_for_new(size_t __align) _NOEXCEPT {
+#ifdef __STDCPP_DEFAULT_NEW_ALIGNMENT__
+  return __align > __STDCPP_DEFAULT_NEW_ALIGNMENT__;
+#else
+  return __align > alignment_of<max_align_t>::value;
+#endif
+}
+
+template <class ..._Args>
+_LIBCPP_INLINE_VISIBILITY
+void* __libcpp_operator_new(_Args ...__args) {
+#if __has_builtin(__builtin_operator_new) && __has_builtin(__builtin_operator_delete)
+  return __builtin_operator_new(__args...);
+#else
+  return ::operator new(__args...);
+#endif
+}
+
+template <class ..._Args>
+_LIBCPP_INLINE_VISIBILITY
+void __libcpp_operator_delete(_Args ...__args) {
+#if __has_builtin(__builtin_operator_new) && __has_builtin(__builtin_operator_delete)
+  __builtin_operator_delete(__args...);
+#else
+  ::operator delete(__args...);
+#endif
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void *__libcpp_allocate(size_t __size, size_t __align) {
+#ifndef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
+  if (__is_overaligned_for_new(__align)) {
+    const align_val_t __align_val = static_cast<align_val_t>(__align);
+    return __libcpp_operator_new(__size, __align_val);
+  }
+#endif
+
+  (void)__align;
+  return __libcpp_operator_new(__size);
+}
+
+template <class ..._Args>
+_LIBCPP_INLINE_VISIBILITY
+void __do_deallocate_handle_size(void *__ptr, size_t __size, _Args ...__args) {
+#ifdef _LIBCPP_HAS_NO_SIZED_DEALLOCATION
+  (void)__size;
+  return __libcpp_operator_delete(__ptr, __args...);
+#else
+  return __libcpp_operator_delete(__ptr, __size, __args...);
+#endif
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void __libcpp_deallocate(void* __ptr, size_t __size, size_t __align) {
+#if defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION)
+    (void)__align;
+    return __do_deallocate_handle_size(__ptr, __size);
+#else
+    if (__is_overaligned_for_new(__align)) {
+      const align_val_t __align_val = static_cast<align_val_t>(__align);
+      return __do_deallocate_handle_size(__ptr, __size, __align_val);
+    } else {
+      return __do_deallocate_handle_size(__ptr, __size);
+    }
+#endif
+}
+
+inline _LIBCPP_INLINE_VISIBILITY void __libcpp_deallocate_unsized(void* __ptr, size_t __align) {
+#if defined(_LIBCPP_HAS_NO_ALIGNED_ALLOCATION)
+    (void)__align;
+    return __libcpp_operator_delete(__ptr);
+#else
+    if (__is_overaligned_for_new(__align)) {
+      const align_val_t __align_val = static_cast<align_val_t>(__align);
+      return __libcpp_operator_delete(__ptr, __align_val);
+    } else {
+      return __libcpp_operator_delete(__ptr);
+    }
+#endif
+}
+
+#if !defined(_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION)
+// Low-level helpers to call the aligned allocation and deallocation functions
+// on the target platform. This is used to implement libc++'s own memory
+// allocation routines -- if you need to allocate memory inside the library,
+// chances are that you want to use `__libcpp_allocate` instead.
+//
+// Returns the allocated memory, or `nullptr` on failure.
+inline _LIBCPP_INLINE_VISIBILITY
+void* __libcpp_aligned_alloc(std::size_t __alignment, std::size_t __size) {
+#if defined(_LIBCPP_MSVCRT_LIKE)
+  return ::_aligned_malloc(__size, __alignment);
+#else
+  void* __result = nullptr;
+  (void)::posix_memalign(&__result, __alignment, __size);
+  // If posix_memalign fails, __result is unmodified so we still return `nullptr`.
+  return __result;
+#endif
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void __libcpp_aligned_free(void* __ptr) {
+#if defined(_LIBCPP_MSVCRT_LIKE)
+  ::_aligned_free(__ptr);
+#else
+  ::free(__ptr);
+#endif
+}
+#endif // !_LIBCPP_HAS_NO_ALIGNED_ALLOCATION
+
+
+template <class _Tp>
+_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_HIDE_FROM_ABI
+_LIBCPP_CONSTEXPR _Tp* __launder(_Tp* __p) _NOEXCEPT
+{
+    static_assert (!(is_function<_Tp>::value), "can't launder functions" );
+    static_assert (!(is_same<void, typename remove_cv<_Tp>::type>::value), "can't launder cv-void" );
+    return __builtin_launder(__p);
+}
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+_LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_HIDE_FROM_ABI
+constexpr _Tp* launder(_Tp* __p) noexcept
+{
+    return _VSTD::__launder(__p);
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_NEW
diff --git a/contrib/libs/cxxsupp/libcxx/include/numbers b/contrib/libs/cxxsupp/libcxx/include/numbers
new file mode 100644
index 00000000000..ced55e0eadf
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/numbers
@@ -0,0 +1,133 @@
+// -*- C++ -*-
+//===---------------------------- numbers ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_NUMBERS
+#define _LIBCPP_NUMBERS
+
+/*
+    numbers synopsis
+
+namespace std::numbers {
+  template<class T> inline constexpr T e_v          = unspecified;
+  template<class T> inline constexpr T log2e_v      = unspecified;
+  template<class T> inline constexpr T log10e_v     = unspecified;
+  template<class T> inline constexpr T pi_v         = unspecified;
+  template<class T> inline constexpr T inv_pi_v     = unspecified;
+  template<class T> inline constexpr T inv_sqrtpi_v = unspecified;
+  template<class T> inline constexpr T ln2_v        = unspecified;
+  template<class T> inline constexpr T ln10_v       = unspecified;
+  template<class T> inline constexpr T sqrt2_v      = unspecified;
+  template<class T> inline constexpr T sqrt3_v      = unspecified;
+  template<class T> inline constexpr T inv_sqrt3_v  = unspecified;
+  template<class T> inline constexpr T egamma_v     = unspecified;
+  template<class T> inline constexpr T phi_v        = unspecified;
+
+  template<floating_point T> inline constexpr T e_v<T>          = see below;
+  template<floating_point T> inline constexpr T log2e_v<T>      = see below;
+  template<floating_point T> inline constexpr T log10e_v<T>     = see below;
+  template<floating_point T> inline constexpr T pi_v<T>         = see below;
+  template<floating_point T> inline constexpr T inv_pi_v<T>     = see below;
+  template<floating_point T> inline constexpr T inv_sqrtpi_v<T> = see below;
+  template<floating_point T> inline constexpr T ln2_v<T>        = see below;
+  template<floating_point T> inline constexpr T ln10_v<T>       = see below;
+  template<floating_point T> inline constexpr T sqrt2_v<T>      = see below;
+  template<floating_point T> inline constexpr T sqrt3_v<T>      = see below;
+  template<floating_point T> inline constexpr T inv_sqrt3_v<T>  = see below;
+  template<floating_point T> inline constexpr T egamma_v<T>     = see below;
+  template<floating_point T> inline constexpr T phi_v<T>        = see below;
+
+  inline constexpr double e          = e_v<double>;
+  inline constexpr double log2e      = log2e_v<double>;
+  inline constexpr double log10e     = log10e_v<double>;
+  inline constexpr double pi         = pi_v<double>;
+  inline constexpr double inv_pi     = inv_pi_v<double>;
+  inline constexpr double inv_sqrtpi = inv_sqrtpi_v<double>;
+  inline constexpr double ln2        = ln2_v<double>;
+  inline constexpr double ln10       = ln10_v<double>;
+  inline constexpr double sqrt2      = sqrt2_v<double>;
+  inline constexpr double sqrt3      = sqrt3_v<double>;
+  inline constexpr double inv_sqrt3  = inv_sqrt3_v<double>;
+  inline constexpr double egamma     = egamma_v<double>;
+  inline constexpr double phi        = phi_v<double>;
+}
+*/
+
+#include <__config>
+#include <concepts>
+#include <type_traits>
+#include <version>
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace numbers {
+
+template <class T>
+inline constexpr bool __false = false;
+
+template <class T>
+struct __illformed
+{
+  static_assert(__false<T>, "A program that instantiates a primary template of a mathematical constant variable template is ill-formed.");
+};
+
+template <class T> inline constexpr T e_v =          __illformed<T>{};
+template <class T> inline constexpr T log2e_v =      __illformed<T>{};
+template <class T> inline constexpr T log10e_v =     __illformed<T>{};
+template <class T> inline constexpr T pi_v =         __illformed<T>{};
+template <class T> inline constexpr T inv_pi_v =     __illformed<T>{};
+template <class T> inline constexpr T inv_sqrtpi_v = __illformed<T>{};
+template <class T> inline constexpr T ln2_v =        __illformed<T>{};
+template <class T> inline constexpr T ln10_v =       __illformed<T>{};
+template <class T> inline constexpr T sqrt2_v =      __illformed<T>{};
+template <class T> inline constexpr T sqrt3_v =      __illformed<T>{};
+template <class T> inline constexpr T inv_sqrt3_v =  __illformed<T>{};
+template <class T> inline constexpr T egamma_v =     __illformed<T>{};
+template <class T> inline constexpr T phi_v =        __illformed<T>{};
+
+template <floating_point T> inline constexpr T e_v<T>          = 2.718281828459045235360287471352662L;
+template <floating_point T> inline constexpr T log2e_v<T>      = 1.442695040888963407359924681001892L;
+template <floating_point T> inline constexpr T log10e_v<T>     = 0.434294481903251827651128918916605L;
+template <floating_point T> inline constexpr T pi_v<T>         = 3.141592653589793238462643383279502L;
+template <floating_point T> inline constexpr T inv_pi_v<T>     = 0.318309886183790671537767526745028L;
+template <floating_point T> inline constexpr T inv_sqrtpi_v<T> = 0.564189583547756286948079451560772L;
+template <floating_point T> inline constexpr T ln2_v<T>        = 0.693147180559945309417232121458176L;
+template <floating_point T> inline constexpr T ln10_v<T>       = 2.302585092994045684017991454684364L;
+template <floating_point T> inline constexpr T sqrt2_v<T>      = 1.414213562373095048801688724209698L;
+template <floating_point T> inline constexpr T sqrt3_v<T>      = 1.732050807568877293527446341505872L;
+template <floating_point T> inline constexpr T inv_sqrt3_v<T>  = 0.577350269189625764509148780501957L;
+template <floating_point T> inline constexpr T egamma_v<T>     = 0.577215664901532860606512090082402L;
+template <floating_point T> inline constexpr T phi_v<T>        = 1.618033988749894848204586834365638L;
+
+inline constexpr double e          = e_v<double>;
+inline constexpr double log2e      = log2e_v<double>;
+inline constexpr double log10e     = log10e_v<double>;
+inline constexpr double pi         = pi_v<double>;
+inline constexpr double inv_pi     = inv_pi_v<double>;
+inline constexpr double inv_sqrtpi = inv_sqrtpi_v<double>;
+inline constexpr double ln2        = ln2_v<double>;
+inline constexpr double ln10       = ln10_v<double>;
+inline constexpr double sqrt2      = sqrt2_v<double>;
+inline constexpr double sqrt3      = sqrt3_v<double>;
+inline constexpr double inv_sqrt3  = inv_sqrt3_v<double>;
+inline constexpr double egamma     = egamma_v<double>;
+inline constexpr double phi        = phi_v<double>;
+
+} // namespace numbers
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif //_LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+#endif // _LIBCPP_NUMBERS
diff --git a/contrib/libs/cxxsupp/libcxx/include/numeric b/contrib/libs/cxxsupp/libcxx/include/numeric
new file mode 100644
index 00000000000..8ea7ecc3753
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/numeric
@@ -0,0 +1,636 @@
+// -*- C++ -*-
+//===---------------------------- numeric ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_NUMERIC
+#define _LIBCPP_NUMERIC
+
+/*
+    numeric synopsis
+
+namespace std
+{
+
+template <class InputIterator, class T>
+    constexpr T  // constexpr since C++20
+    accumulate(InputIterator first, InputIterator last, T init);
+
+template <class InputIterator, class T, class BinaryOperation>
+    constexpr T  // constexpr since C++20
+    accumulate(InputIterator first, InputIterator last, T init, BinaryOperation binary_op);
+
+template<class InputIterator>
+    constexpr typename iterator_traits<InputIterator>::value_type  // constexpr since C++20
+    reduce(InputIterator first, InputIterator last);  // C++17
+
+template<class InputIterator, class T>
+    constexpr T  // constexpr since C++20
+    reduce(InputIterator first, InputIterator last, T init);  // C++17
+
+template<class InputIterator, class T, class BinaryOperation>
+    constexpr T  // constexpr since C++20
+    reduce(InputIterator first, InputIterator last, T init, BinaryOperation binary_op);  // C++17
+
+template <class InputIterator1, class InputIterator2, class T>
+    constexpr T  // constexpr since C++20
+    inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, T init);
+
+template <class InputIterator1, class InputIterator2, class T, class BinaryOperation1, class BinaryOperation2>
+    constexpr T  // constexpr since C++20
+    inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2,
+                  T init, BinaryOperation1 binary_op1, BinaryOperation2 binary_op2);
+
+
+template<class InputIterator1, class InputIterator2, class T>
+    constexpr T  // constexpr since C++20
+    transform_reduce(InputIterator1 first1, InputIterator1 last1,
+                     InputIterator2 first2, T init);  // C++17
+
+template<class InputIterator1, class InputIterator2, class T, class BinaryOperation1, class BinaryOperation2>
+    constexpr T  // constexpr since C++20
+    transform_reduce(InputIterator1 first1, InputIterator1 last1,
+                     InputIterator2 first2, T init,
+                     BinaryOperation1 binary_op1, BinaryOperation2 binary_op2);  // C++17
+
+template<class InputIterator, class T, class BinaryOperation, class UnaryOperation>
+    constexpr T  // constexpr since C++20
+    transform_reduce(InputIterator first, InputIterator last, T init,
+                     BinaryOperation binary_op, UnaryOperation unary_op);  // C++17
+
+template <class InputIterator, class OutputIterator>
+    constexpr OutputIterator  // constexpr since C++20
+    partial_sum(InputIterator first, InputIterator last, OutputIterator result);
+
+template <class InputIterator, class OutputIterator, class BinaryOperation>
+    constexpr OutputIterator  // constexpr since C++20
+    partial_sum(InputIterator first, InputIterator last, OutputIterator result, BinaryOperation binary_op);
+
+template<class InputIterator, class OutputIterator, class T>
+    constexpr OutputIterator  // constexpr since C++20
+    exclusive_scan(InputIterator first, InputIterator last,
+                   OutputIterator result, T init); // C++17
+
+template<class InputIterator, class OutputIterator, class T, class BinaryOperation>
+    constexpr OutputIterator  // constexpr since C++20
+    exclusive_scan(InputIterator first, InputIterator last,
+                   OutputIterator result, T init, BinaryOperation binary_op); // C++17
+
+template<class InputIterator, class OutputIterator>
+    constexpr OutputIterator  // constexpr since C++20
+    inclusive_scan(InputIterator first, InputIterator last, OutputIterator result);  // C++17
+
+template<class InputIterator, class OutputIterator, class BinaryOperation>
+    constexpr OutputIterator  // constexpr since C++20
+    inclusive_scan(InputIterator first, InputIterator last,
+                   OutputIterator result, BinaryOperation binary_op);  // C++17
+
+template<class InputIterator, class OutputIterator, class BinaryOperation, class T>
+    constexpr OutputIterator  // constexpr since C++20
+    inclusive_scan(InputIterator first, InputIterator last,
+                   OutputIterator result, BinaryOperation binary_op, T init);  // C++17
+
+template<class InputIterator, class OutputIterator, class T,
+         class BinaryOperation, class UnaryOperation>
+    constexpr OutputIterator  // constexpr since C++20
+    transform_exclusive_scan(InputIterator first, InputIterator last,
+                             OutputIterator result, T init,
+                             BinaryOperation binary_op, UnaryOperation unary_op);  // C++17
+
+template<class InputIterator, class OutputIterator,
+         class BinaryOperation, class UnaryOperation>
+    constexpr OutputIterator  // constexpr since C++20
+    transform_inclusive_scan(InputIterator first, InputIterator last,
+                             OutputIterator result,
+                             BinaryOperation binary_op, UnaryOperation unary_op);  // C++17
+
+template<class InputIterator, class OutputIterator,
+         class BinaryOperation, class UnaryOperation, class T>
+    constexpr OutputIterator  // constexpr since C++20
+    transform_inclusive_scan(InputIterator first, InputIterator last,
+                             OutputIterator result,
+                             BinaryOperation binary_op, UnaryOperation unary_op,
+                             T init);  // C++17
+
+template <class InputIterator, class OutputIterator>
+    constexpr OutputIterator  // constexpr since C++20
+    adjacent_difference(InputIterator first, InputIterator last, OutputIterator result);
+
+template <class InputIterator, class OutputIterator, class BinaryOperation>
+    constexpr OutputIterator  // constexpr since C++20
+    adjacent_difference(InputIterator first, InputIterator last, OutputIterator result, BinaryOperation binary_op);
+
+template <class ForwardIterator, class T>
+    constexpr void  // constexpr since C++20
+    iota(ForwardIterator first, ForwardIterator last, T value);
+
+template <class M, class N>
+    constexpr common_type_t<M,N> gcd(M m, N n);    // C++17
+
+template <class M, class N>
+    constexpr common_type_t<M,N> lcm(M m, N n);    // C++17
+
+template<class T>
+    constexpr T midpoint(T a, T b) noexcept;  // C++20
+
+template<class T>
+    constexpr T* midpoint(T* a, T* b);        // C++20
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <cmath> // for isnormal
+#include <functional>
+#include <iterator>
+#include <limits> // for numeric_limits
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_Tp
+accumulate(_InputIterator __first, _InputIterator __last, _Tp __init)
+{
+    for (; __first != __last; ++__first)
+#if _LIBCPP_STD_VER > 17
+        __init = _VSTD::move(__init) + *__first;
+#else
+        __init = __init + *__first;
+#endif
+    return __init;
+}
+
+template <class _InputIterator, class _Tp, class _BinaryOperation>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_Tp
+accumulate(_InputIterator __first, _InputIterator __last, _Tp __init, _BinaryOperation __binary_op)
+{
+    for (; __first != __last; ++__first)
+#if _LIBCPP_STD_VER > 17
+        __init = __binary_op(_VSTD::move(__init), *__first);
+#else
+        __init = __binary_op(__init, *__first);
+#endif
+    return __init;
+}
+
+#if _LIBCPP_STD_VER > 14
+template <class _InputIterator, class _Tp, class _BinaryOp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_Tp
+reduce(_InputIterator __first, _InputIterator __last, _Tp __init, _BinaryOp __b)
+{
+    for (; __first != __last; ++__first)
+        __init = __b(__init, *__first);
+    return __init;
+}
+
+template <class _InputIterator, class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_Tp
+reduce(_InputIterator __first, _InputIterator __last, _Tp __init)
+{
+    return _VSTD::reduce(__first, __last, __init, _VSTD::plus<>());
+}
+
+template <class _InputIterator>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+typename iterator_traits<_InputIterator>::value_type
+reduce(_InputIterator __first, _InputIterator __last)
+{
+    return _VSTD::reduce(__first, __last,
+       typename iterator_traits<_InputIterator>::value_type{});
+}
+#endif
+
+template <class _InputIterator1, class _InputIterator2, class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_Tp
+inner_product(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _Tp __init)
+{
+    for (; __first1 != __last1; ++__first1, (void) ++__first2)
+#if _LIBCPP_STD_VER > 17
+        __init = _VSTD::move(__init) + *__first1 * *__first2;
+#else
+        __init = __init + *__first1 * *__first2;
+#endif
+    return __init;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Tp, class _BinaryOperation1, class _BinaryOperation2>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_Tp
+inner_product(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2,
+              _Tp __init, _BinaryOperation1 __binary_op1, _BinaryOperation2 __binary_op2)
+{
+    for (; __first1 != __last1; ++__first1, (void) ++__first2)
+#if _LIBCPP_STD_VER > 17
+        __init = __binary_op1(_VSTD::move(__init), __binary_op2(*__first1, *__first2));
+#else
+        __init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
+#endif
+    return __init;
+}
+
+#if _LIBCPP_STD_VER > 14
+template <class _InputIterator, class _Tp, class _BinaryOp, class _UnaryOp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_Tp
+transform_reduce(_InputIterator __first, _InputIterator __last,
+           _Tp __init,  _BinaryOp __b, _UnaryOp __u)
+{
+    for (; __first != __last; ++__first)
+        __init = __b(__init, __u(*__first));
+    return __init;
+}
+
+template <class _InputIterator1, class _InputIterator2,
+          class _Tp, class _BinaryOp1, class _BinaryOp2>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_Tp
+transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1,
+                 _InputIterator2 __first2, _Tp __init,  _BinaryOp1 __b1, _BinaryOp2 __b2)
+{
+    for (; __first1 != __last1; ++__first1, (void) ++__first2)
+        __init = __b1(__init, __b2(*__first1, *__first2));
+    return __init;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_Tp
+transform_reduce(_InputIterator1 __first1, _InputIterator1 __last1,
+                 _InputIterator2 __first2, _Tp __init)
+{
+    return _VSTD::transform_reduce(__first1, __last1, __first2, _VSTD::move(__init),
+                                   _VSTD::plus<>(), _VSTD::multiplies<>());
+}
+#endif
+
+template <class _InputIterator, class _OutputIterator>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    if (__first != __last)
+    {
+        typename iterator_traits<_InputIterator>::value_type __t(*__first);
+        *__result = __t;
+        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
+        {
+#if _LIBCPP_STD_VER > 17
+            __t = _VSTD::move(__t) + *__first;
+#else
+            __t = __t + *__first;
+#endif
+            *__result = __t;
+        }
+    }
+    return __result;
+}
+
+template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
+              _BinaryOperation __binary_op)
+{
+    if (__first != __last)
+    {
+        typename iterator_traits<_InputIterator>::value_type __t(*__first);
+        *__result = __t;
+        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
+        {
+#if _LIBCPP_STD_VER > 17
+            __t = __binary_op(_VSTD::move(__t), *__first);
+#else
+            __t = __binary_op(__t, *__first);
+#endif
+            *__result = __t;
+        }
+    }
+    return __result;
+}
+
+#if _LIBCPP_STD_VER > 14
+template <class _InputIterator, class _OutputIterator, class _Tp, class _BinaryOp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+exclusive_scan(_InputIterator __first, _InputIterator __last,
+               _OutputIterator __result, _Tp __init, _BinaryOp __b)
+{
+    if (__first != __last)
+    {
+        _Tp __tmp(__b(__init, *__first));
+        while (true)
+        {
+            *__result = _VSTD::move(__init);
+            ++__result;
+            ++__first;
+            if (__first == __last)
+                break;
+            __init = _VSTD::move(__tmp);
+            __tmp = __b(__init, *__first);
+        }
+    }
+    return __result;
+}
+
+template <class _InputIterator, class _OutputIterator, class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+exclusive_scan(_InputIterator __first, _InputIterator __last,
+               _OutputIterator __result, _Tp __init)
+{
+    return _VSTD::exclusive_scan(__first, __last, __result, __init, _VSTD::plus<>());
+}
+
+template <class _InputIterator, class _OutputIterator, class _Tp, class _BinaryOp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator inclusive_scan(_InputIterator __first, _InputIterator __last,
+                               _OutputIterator __result, _BinaryOp __b,  _Tp __init)
+{
+    for (; __first != __last; ++__first, (void) ++__result) {
+        __init = __b(__init, *__first);
+        *__result = __init;
+    }
+    return __result;
+}
+
+template <class _InputIterator, class _OutputIterator, class _BinaryOp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator inclusive_scan(_InputIterator __first, _InputIterator __last,
+                               _OutputIterator __result, _BinaryOp __b)
+{
+    if (__first != __last) {
+        typename iterator_traits<_InputIterator>::value_type __init = *__first;
+        *__result++ = __init;
+        if (++__first != __last)
+            return _VSTD::inclusive_scan(__first, __last, __result, __b, __init);
+    }
+
+    return __result;
+}
+
+template <class _InputIterator, class _OutputIterator>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator inclusive_scan(_InputIterator __first, _InputIterator __last,
+                               _OutputIterator __result)
+{
+    return _VSTD::inclusive_scan(__first, __last, __result, _VSTD::plus<>());
+}
+
+template <class _InputIterator, class _OutputIterator, class _Tp,
+          class _BinaryOp, class _UnaryOp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+transform_exclusive_scan(_InputIterator __first, _InputIterator __last,
+                           _OutputIterator __result, _Tp __init,
+                           _BinaryOp __b, _UnaryOp __u)
+{
+    if (__first != __last)
+    {
+        _Tp __saved = __init;
+        do
+        {
+            __init = __b(__init, __u(*__first));
+            *__result = __saved;
+            __saved = __init;
+            ++__result;
+        } while (++__first != __last);
+    }
+    return __result;
+}
+
+template <class _InputIterator, class _OutputIterator, class _Tp, class _BinaryOp, class _UnaryOp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+transform_inclusive_scan(_InputIterator __first, _InputIterator __last,
+                           _OutputIterator __result, _BinaryOp __b, _UnaryOp __u, _Tp __init)
+{
+    for (; __first != __last; ++__first, (void) ++__result) {
+        __init = __b(__init, __u(*__first));
+        *__result = __init;
+        }
+
+    return __result;
+}
+
+template <class _InputIterator, class _OutputIterator, class _BinaryOp, class _UnaryOp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+transform_inclusive_scan(_InputIterator __first, _InputIterator __last,
+                               _OutputIterator __result, _BinaryOp __b, _UnaryOp __u)
+{
+    if (__first != __last) {
+        typename iterator_traits<_InputIterator>::value_type __init = __u(*__first);
+        *__result++ = __init;
+        if (++__first != __last)
+            return _VSTD::transform_inclusive_scan(__first, __last, __result, __b, __u, __init);
+    }
+
+    return __result;
+}
+#endif
+
+template <class _InputIterator, class _OutputIterator>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
+{
+    if (__first != __last)
+    {
+        typename iterator_traits<_InputIterator>::value_type __acc(*__first);
+        *__result = __acc;
+        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
+        {
+            typename iterator_traits<_InputIterator>::value_type __val(*__first);
+#if _LIBCPP_STD_VER > 17
+            *__result = __val - _VSTD::move(__acc);
+#else
+            *__result = __val - __acc;
+#endif
+            __acc = _VSTD::move(__val);
+        }
+    }
+    return __result;
+}
+
+template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+_OutputIterator
+adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
+                      _BinaryOperation __binary_op)
+{
+    if (__first != __last)
+    {
+        typename iterator_traits<_InputIterator>::value_type __acc(*__first);
+        *__result = __acc;
+        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
+        {
+            typename iterator_traits<_InputIterator>::value_type __val(*__first);
+#if _LIBCPP_STD_VER > 17
+            *__result = __binary_op(__val, _VSTD::move(__acc));
+#else
+            *__result = __binary_op(__val, __acc);
+#endif
+            __acc = _VSTD::move(__val);
+        }
+    }
+    return __result;
+}
+
+template <class _ForwardIterator, class _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+void
+iota(_ForwardIterator __first, _ForwardIterator __last, _Tp __value_)
+{
+    for (; __first != __last; ++__first, (void) ++__value_)
+        *__first = __value_;
+}
+
+
+#if _LIBCPP_STD_VER > 14
+template <typename _Result, typename _Source, bool _IsSigned = is_signed<_Source>::value> struct __ct_abs;
+
+template <typename _Result, typename _Source>
+struct __ct_abs<_Result, _Source, true> {
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    _Result operator()(_Source __t) const noexcept
+    {
+        if (__t >= 0) return __t;
+        if (__t == numeric_limits<_Source>::min()) return -static_cast<_Result>(__t);
+        return -__t;
+    }
+};
+
+template <typename _Result, typename _Source>
+struct __ct_abs<_Result, _Source, false> {
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    _Result operator()(_Source __t) const noexcept { return __t; }
+};
+
+
+template<class _Tp>
+_LIBCPP_CONSTEXPR _LIBCPP_HIDDEN
+_Tp __gcd(_Tp __m, _Tp __n)
+{
+    static_assert((!is_signed<_Tp>::value), "");
+    return __n == 0 ? __m : _VSTD::__gcd<_Tp>(__n, __m % __n);
+}
+
+
+template<class _Tp, class _Up>
+_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+common_type_t<_Tp,_Up>
+gcd(_Tp __m, _Up __n)
+{
+    static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to gcd must be integer types");
+    static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to gcd cannot be bool" );
+    static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to gcd cannot be bool" );
+    using _Rp = common_type_t<_Tp,_Up>;
+    using _Wp = make_unsigned_t<_Rp>;
+    return static_cast<_Rp>(_VSTD::__gcd(
+        static_cast<_Wp>(__ct_abs<_Rp, _Tp>()(__m)),
+        static_cast<_Wp>(__ct_abs<_Rp, _Up>()(__n))));
+}
+
+template<class _Tp, class _Up>
+_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+common_type_t<_Tp,_Up>
+lcm(_Tp __m, _Up __n)
+{
+    static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to lcm must be integer types");
+    static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to lcm cannot be bool" );
+    static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to lcm cannot be bool" );
+    if (__m == 0 || __n == 0)
+        return 0;
+
+    using _Rp = common_type_t<_Tp,_Up>;
+    _Rp __val1 = __ct_abs<_Rp, _Tp>()(__m) / _VSTD::gcd(__m, __n);
+    _Rp __val2 = __ct_abs<_Rp, _Up>()(__n);
+    _LIBCPP_ASSERT((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow in lcm");
+    return __val1 * __val2;
+}
+
+#endif /* _LIBCPP_STD_VER > 14 */
+
+#if _LIBCPP_STD_VER > 17
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<is_integral_v<_Tp> && !is_same_v<bool, _Tp> && !is_null_pointer_v<_Tp>, _Tp>
+midpoint(_Tp __a, _Tp __b) noexcept
+_LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+{
+    using _Up = make_unsigned_t<_Tp>;
+    constexpr _Up __bitshift = numeric_limits<_Up>::digits - 1;
+
+    _Up __diff = _Up(__b) - _Up(__a);
+    _Up __sign_bit = __b < __a;
+
+    _Up __half_diff = (__diff / 2) + (__sign_bit << __bitshift) + (__sign_bit & __diff);
+
+    return __a + __half_diff;
+}
+
+
+template <class _TPtr>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<is_pointer_v<_TPtr>
+             && is_object_v<remove_pointer_t<_TPtr>>
+             && ! is_void_v<remove_pointer_t<_TPtr>>
+             && (sizeof(remove_pointer_t<_TPtr>) > 0), _TPtr>
+midpoint(_TPtr __a, _TPtr __b) noexcept
+{
+    return __a + _VSTD::midpoint(ptrdiff_t(0), __b - __a);
+}
+
+
+template <typename _Tp>
+constexpr int __sign(_Tp __val) {
+    return (_Tp(0) < __val) - (__val < _Tp(0));
+}
+
+template <typename _Fp>
+constexpr _Fp __fp_abs(_Fp __f) { return __f >= 0 ? __f : -__f; }
+
+template <class _Fp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<is_floating_point_v<_Fp>, _Fp>
+midpoint(_Fp __a, _Fp __b) noexcept
+{
+	constexpr _Fp __lo = numeric_limits<_Fp>::min()*2;
+	constexpr _Fp __hi = numeric_limits<_Fp>::max()/2;
+    return __fp_abs(__a) <= __hi && __fp_abs(__b) <= __hi ?  // typical case: overflow is impossible
+      (__a + __b)/2 :                                        // always correctly rounded
+      __fp_abs(__a) < __lo ? __a + __b/2 :                   // not safe to halve a
+      __fp_abs(__b) < __lo ? __a/2 + __b :                   // not safe to halve b
+      __a/2 + __b/2;                                         // otherwise correctly rounded
+}
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#if defined(_LIBCPP_HAS_PARALLEL_ALGORITHMS) && _LIBCPP_STD_VER >= 17
+//#   include <__pstl_numeric>
+#endif
+
+#endif // _LIBCPP_NUMERIC
diff --git a/contrib/libs/cxxsupp/libcxx/include/optional b/contrib/libs/cxxsupp/libcxx/include/optional
new file mode 100644
index 00000000000..0f6d2330511
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/optional
@@ -0,0 +1,1392 @@
+// -*- C++ -*-
+//===-------------------------- optional ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_OPTIONAL
+#define _LIBCPP_OPTIONAL
+
+/*
+    optional synopsis
+
+// C++1z
+
+namespace std {
+  // 23.6.3, optional for object types
+  template <class T> class optional;
+
+  // 23.6.4, no-value state indicator
+  struct nullopt_t{see below };
+  inline constexpr nullopt_t nullopt(unspecified );
+
+  // 23.6.5, class bad_optional_access
+  class bad_optional_access;
+
+  // 23.6.6, relational operators
+  template <class T, class U>
+  constexpr bool operator==(const optional<T>&, const optional<U>&);
+  template <class T, class U>
+  constexpr bool operator!=(const optional<T>&, const optional<U>&);
+  template <class T, class U>
+  constexpr bool operator<(const optional<T>&, const optional<U>&);
+  template <class T, class U>
+  constexpr bool operator>(const optional<T>&, const optional<U>&);
+  template <class T, class U>
+  constexpr bool operator<=(const optional<T>&, const optional<U>&);
+  template <class T, class U>
+  constexpr bool operator>=(const optional<T>&, const optional<U>&);
+
+  // 23.6.7 comparison with nullopt
+  template <class T> constexpr bool operator==(const optional<T>&, nullopt_t) noexcept;
+  template <class T> constexpr bool operator==(nullopt_t, const optional<T>&) noexcept;
+  template <class T> constexpr bool operator!=(const optional<T>&, nullopt_t) noexcept;
+  template <class T> constexpr bool operator!=(nullopt_t, const optional<T>&) noexcept;
+  template <class T> constexpr bool operator<(const optional<T>&, nullopt_t) noexcept;
+  template <class T> constexpr bool operator<(nullopt_t, const optional<T>&) noexcept;
+  template <class T> constexpr bool operator<=(const optional<T>&, nullopt_t) noexcept;
+  template <class T> constexpr bool operator<=(nullopt_t, const optional<T>&) noexcept;
+  template <class T> constexpr bool operator>(const optional<T>&, nullopt_t) noexcept;
+  template <class T> constexpr bool operator>(nullopt_t, const optional<T>&) noexcept;
+  template <class T> constexpr bool operator>=(const optional<T>&, nullopt_t) noexcept;
+  template <class T> constexpr bool operator>=(nullopt_t, const optional<T>&) noexcept;
+
+  // 23.6.8, comparison with T
+  template <class T, class U> constexpr bool operator==(const optional<T>&, const U&);
+  template <class T, class U> constexpr bool operator==(const T&, const optional<U>&);
+  template <class T, class U> constexpr bool operator!=(const optional<T>&, const U&);
+  template <class T, class U> constexpr bool operator!=(const T&, const optional<U>&);
+  template <class T, class U> constexpr bool operator<(const optional<T>&, const U&);
+  template <class T, class U> constexpr bool operator<(const T&, const optional<U>&);
+  template <class T, class U> constexpr bool operator<=(const optional<T>&, const U&);
+  template <class T, class U> constexpr bool operator<=(const T&, const optional<U>&);
+  template <class T, class U> constexpr bool operator>(const optional<T>&, const U&);
+  template <class T, class U> constexpr bool operator>(const T&, const optional<U>&);
+  template <class T, class U> constexpr bool operator>=(const optional<T>&, const U&);
+  template <class T, class U> constexpr bool operator>=(const T&, const optional<U>&);
+
+  // 23.6.9, specialized algorithms
+  template <class T> void swap(optional<T>&, optional<T>&) noexcept(see below ); // constexpr in C++20
+  template <class T> constexpr optional<see below > make_optional(T&&);
+  template <class T, class... Args>
+    constexpr optional<T> make_optional(Args&&... args);
+  template <class T, class U, class... Args>
+    constexpr optional<T> make_optional(initializer_list<U> il, Args&&... args);
+
+  // 23.6.10, hash support
+  template <class T> struct hash;
+  template <class T> struct hash<optional<T>>;
+
+  template <class T> class optional {
+  public:
+    using value_type = T;
+
+    // 23.6.3.1, constructors
+    constexpr optional() noexcept;
+    constexpr optional(nullopt_t) noexcept;
+    optional(const optional &);
+    optional(optional &&) noexcept(see below);
+    template <class... Args> constexpr explicit optional(in_place_t, Args &&...);
+    template <class U, class... Args>
+      constexpr explicit optional(in_place_t, initializer_list<U>, Args &&...);
+    template <class U = T>
+      constexpr EXPLICIT optional(U &&);
+    template <class U>
+      EXPLICIT optional(const optional<U> &);   // constexpr in C++20
+    template <class U>
+      EXPLICIT optional(optional<U> &&);        // constexpr in C++20
+
+    // 23.6.3.2, destructor
+    ~optional(); // constexpr in C++20
+
+    // 23.6.3.3, assignment
+    optional &operator=(nullopt_t) noexcept;                     // constexpr in C++20
+    optional &operator=(const optional &);                       // constexpr in C++20
+    optional &operator=(optional &&) noexcept(see below);        // constexpr in C++20
+    template <class U = T> optional &operator=(U &&);            // constexpr in C++20
+    template <class U> optional &operator=(const optional<U> &); // constexpr in C++20
+    template <class U> optional &operator=(optional<U> &&);      // constexpr in C++20
+    template <class... Args> T& emplace(Args &&...);             // constexpr in C++20
+    template <class U, class... Args>
+      T& emplace(initializer_list<U>, Args &&...);               // constexpr in C++20
+
+    // 23.6.3.4, swap
+    void swap(optional &) noexcept(see below ); // constexpr in C++20
+
+    // 23.6.3.5, observers
+    constexpr T const *operator->() const;
+    constexpr T *operator->();
+    constexpr T const &operator*() const &;
+    constexpr T &operator*() &;
+    constexpr T &&operator*() &&;
+    constexpr const T &&operator*() const &&;
+    constexpr explicit operator bool() const noexcept;
+    constexpr bool has_value() const noexcept;
+    constexpr T const &value() const &;
+    constexpr T &value() &;
+    constexpr T &&value() &&;
+    constexpr const T &&value() const &&;
+    template <class U> constexpr T value_or(U &&) const &;
+    template <class U> constexpr T value_or(U &&) &&;
+
+    // 23.6.3.6, modifiers
+    void reset() noexcept; // constexpr in C++20
+
+  private:
+    T *val; // exposition only
+  };
+
+template<class T>
+  optional(T) -> optional<T>;
+
+} // namespace std
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <__debug>
+#include <__functional_base>
+#include <compare>
+#include <functional>
+#include <initializer_list>
+#include <new>
+#include <stdexcept>
+#include <type_traits>
+#include <utility>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+namespace std  // purposefully not using versioning namespace
+{
+
+class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS bad_optional_access
+    : public exception
+{
+public:
+    // Get the key function ~bad_optional_access() into the dylib
+    virtual ~bad_optional_access() _NOEXCEPT;
+    virtual const char* what() const _NOEXCEPT;
+};
+
+}  // std
+
+#if _LIBCPP_STD_VER > 14
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+_LIBCPP_NORETURN
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS
+void __throw_bad_optional_access() {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        throw bad_optional_access();
+#else
+        _VSTD::abort();
+#endif
+}
+
+struct nullopt_t
+{
+    struct __secret_tag { _LIBCPP_INLINE_VISIBILITY explicit __secret_tag() = default; };
+    _LIBCPP_INLINE_VISIBILITY constexpr explicit nullopt_t(__secret_tag, __secret_tag) noexcept {}
+};
+
+inline constexpr nullopt_t nullopt{nullopt_t::__secret_tag{}, nullopt_t::__secret_tag{}};
+
+template <class _Tp, bool = is_trivially_destructible<_Tp>::value>
+struct __optional_destruct_base;
+
+template <class _Tp>
+struct __optional_destruct_base<_Tp, false>
+{
+    typedef _Tp value_type;
+    static_assert(is_object_v<value_type>,
+        "instantiation of optional with a non-object type is undefined behavior");
+    union
+    {
+        char __null_state_;
+        value_type __val_;
+    };
+    bool __engaged_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    /* _LIBCPP_CONSTEXPR_AFTER_CXX17 */ ~__optional_destruct_base()
+    {
+        if (__engaged_)
+            __val_.~value_type();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr __optional_destruct_base() noexcept
+        :  __null_state_(),
+           __engaged_(false) {}
+
+    template <class... _Args>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit __optional_destruct_base(in_place_t, _Args&&... __args)
+        :  __val_(_VSTD::forward<_Args>(__args)...),
+           __engaged_(true) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 void reset() noexcept
+    {
+        if (__engaged_)
+        {
+            __val_.~value_type();
+            __engaged_ = false;
+        }
+    }
+};
+
+template <class _Tp>
+struct __optional_destruct_base<_Tp, true>
+{
+    typedef _Tp value_type;
+    static_assert(is_object_v<value_type>,
+        "instantiation of optional with a non-object type is undefined behavior");
+    union
+    {
+        char __null_state_;
+        value_type __val_;
+    };
+    bool __engaged_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr __optional_destruct_base() noexcept
+        :  __null_state_(),
+           __engaged_(false) {}
+
+    template <class... _Args>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit __optional_destruct_base(in_place_t, _Args&&... __args)
+        :  __val_(_VSTD::forward<_Args>(__args)...),
+           __engaged_(true) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 void reset() noexcept
+    {
+        if (__engaged_)
+        {
+            __engaged_ = false;
+        }
+    }
+};
+
+template <class _Tp, bool = is_reference<_Tp>::value>
+struct __optional_storage_base : __optional_destruct_base<_Tp>
+{
+    using __base = __optional_destruct_base<_Tp>;
+    using value_type = _Tp;
+    using __base::__base;
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr bool has_value() const noexcept
+    {
+        return this->__engaged_;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr value_type& __get() & noexcept
+    {
+        return this->__val_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr const value_type& __get() const& noexcept
+    {
+        return this->__val_;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr value_type&& __get() && noexcept
+    {
+        return _VSTD::move(this->__val_);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr const value_type&& __get() const&& noexcept
+    {
+        return _VSTD::move(this->__val_);
+    }
+
+    template <class... _Args>
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 void __construct(_Args&&... __args)
+    {
+        _LIBCPP_ASSERT(!has_value(), "__construct called for engaged __optional_storage");
+#if _LIBCPP_STD_VER > 17
+        _VSTD::construct_at(_VSTD::addressof(this->__val_), _VSTD::forward<_Args>(__args)...);
+#else
+        ::new ((void*)_VSTD::addressof(this->__val_)) value_type(_VSTD::forward<_Args>(__args)...);
+#endif
+        this->__engaged_ = true;
+    }
+
+    template <class _That>
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 void __construct_from(_That&& __opt)
+    {
+        if (__opt.has_value())
+            __construct(_VSTD::forward<_That>(__opt).__get());
+    }
+
+    template <class _That>
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 void __assign_from(_That&& __opt)
+    {
+        if (this->__engaged_ == __opt.has_value())
+        {
+            if (this->__engaged_)
+                this->__val_ = _VSTD::forward<_That>(__opt).__get();
+        }
+        else
+        {
+            if (this->__engaged_)
+                this->reset();
+            else
+                __construct(_VSTD::forward<_That>(__opt).__get());
+        }
+    }
+};
+
+// optional<T&> is currently required ill-formed, however it may to be in the
+// future. For this reason it has already been implemented to ensure we can
+// make the change in an ABI compatible manner.
+template <class _Tp>
+struct __optional_storage_base<_Tp, true>
+{
+    using value_type = _Tp;
+    using __raw_type = remove_reference_t<_Tp>;
+    __raw_type* __value_;
+
+    template <class _Up>
+    static constexpr bool __can_bind_reference() {
+        using _RawUp = typename remove_reference<_Up>::type;
+        using _UpPtr = _RawUp*;
+        using _RawTp = typename remove_reference<_Tp>::type;
+        using _TpPtr = _RawTp*;
+        using _CheckLValueArg = integral_constant<bool,
+            (is_lvalue_reference<_Up>::value && is_convertible<_UpPtr, _TpPtr>::value)
+        ||  is_same<_RawUp, reference_wrapper<_RawTp>>::value
+        ||  is_same<_RawUp, reference_wrapper<typename remove_const<_RawTp>::type>>::value
+        >;
+        return (is_lvalue_reference<_Tp>::value && _CheckLValueArg::value)
+            || (is_rvalue_reference<_Tp>::value && !is_lvalue_reference<_Up>::value &&
+                is_convertible<_UpPtr, _TpPtr>::value);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr __optional_storage_base() noexcept
+        :  __value_(nullptr) {}
+
+    template <class _UArg>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit __optional_storage_base(in_place_t, _UArg&& __uarg)
+        :  __value_(_VSTD::addressof(__uarg))
+    {
+      static_assert(__can_bind_reference<_UArg>(),
+        "Attempted to construct a reference element in tuple from a "
+        "possible temporary");
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 void reset() noexcept { __value_ = nullptr; }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr bool has_value() const noexcept
+      { return __value_ != nullptr; }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr value_type& __get() const& noexcept
+      { return *__value_; }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr value_type&& __get() const&& noexcept
+      { return _VSTD::forward<value_type>(*__value_); }
+
+    template <class _UArg>
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 void __construct(_UArg&& __val)
+    {
+        _LIBCPP_ASSERT(!has_value(), "__construct called for engaged __optional_storage");
+        static_assert(__can_bind_reference<_UArg>(),
+            "Attempted to construct a reference element in tuple from a "
+            "possible temporary");
+        __value_ = _VSTD::addressof(__val);
+    }
+
+    template <class _That>
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 void __construct_from(_That&& __opt)
+    {
+        if (__opt.has_value())
+            __construct(_VSTD::forward<_That>(__opt).__get());
+    }
+
+    template <class _That>
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 void __assign_from(_That&& __opt)
+    {
+        if (has_value() == __opt.has_value())
+        {
+            if (has_value())
+                *__value_ = _VSTD::forward<_That>(__opt).__get();
+        }
+        else
+        {
+            if (has_value())
+                reset();
+            else
+                __construct(_VSTD::forward<_That>(__opt).__get());
+        }
+    }
+};
+
+template <class _Tp, bool = is_trivially_copy_constructible<_Tp>::value>
+struct __optional_copy_base : __optional_storage_base<_Tp>
+{
+    using __optional_storage_base<_Tp>::__optional_storage_base;
+};
+
+template <class _Tp>
+struct __optional_copy_base<_Tp, false> : __optional_storage_base<_Tp>
+{
+    using __optional_storage_base<_Tp>::__optional_storage_base;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_copy_base() = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 __optional_copy_base(const __optional_copy_base& __opt)
+    {
+        this->__construct_from(__opt);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_copy_base(__optional_copy_base&&) = default;
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_copy_base& operator=(const __optional_copy_base&) = default;
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_copy_base& operator=(__optional_copy_base&&) = default;
+};
+
+template <class _Tp, bool = is_trivially_move_constructible<_Tp>::value>
+struct __optional_move_base : __optional_copy_base<_Tp>
+{
+    using __optional_copy_base<_Tp>::__optional_copy_base;
+};
+
+template <class _Tp>
+struct __optional_move_base<_Tp, false> : __optional_copy_base<_Tp>
+{
+    using value_type = _Tp;
+    using __optional_copy_base<_Tp>::__optional_copy_base;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_move_base() = default;
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_move_base(const __optional_move_base&) = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 __optional_move_base(__optional_move_base&& __opt)
+        noexcept(is_nothrow_move_constructible_v<value_type>)
+    {
+        this->__construct_from(_VSTD::move(__opt));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_move_base& operator=(const __optional_move_base&) = default;
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_move_base& operator=(__optional_move_base&&) = default;
+};
+
+template <class _Tp, bool =
+    is_trivially_destructible<_Tp>::value &&
+    is_trivially_copy_constructible<_Tp>::value &&
+    is_trivially_copy_assignable<_Tp>::value>
+struct __optional_copy_assign_base : __optional_move_base<_Tp>
+{
+    using __optional_move_base<_Tp>::__optional_move_base;
+};
+
+template <class _Tp>
+struct __optional_copy_assign_base<_Tp, false> : __optional_move_base<_Tp>
+{
+    using __optional_move_base<_Tp>::__optional_move_base;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_copy_assign_base() = default;
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_copy_assign_base(const __optional_copy_assign_base&) = default;
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_copy_assign_base(__optional_copy_assign_base&&) = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 __optional_copy_assign_base& operator=(const __optional_copy_assign_base& __opt)
+    {
+        this->__assign_from(__opt);
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_copy_assign_base& operator=(__optional_copy_assign_base&&) = default;
+};
+
+template <class _Tp, bool =
+    is_trivially_destructible<_Tp>::value &&
+    is_trivially_move_constructible<_Tp>::value &&
+    is_trivially_move_assignable<_Tp>::value>
+struct __optional_move_assign_base : __optional_copy_assign_base<_Tp>
+{
+    using __optional_copy_assign_base<_Tp>::__optional_copy_assign_base;
+};
+
+template <class _Tp>
+struct __optional_move_assign_base<_Tp, false> : __optional_copy_assign_base<_Tp>
+{
+    using value_type = _Tp;
+    using __optional_copy_assign_base<_Tp>::__optional_copy_assign_base;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_move_assign_base() = default;
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_move_assign_base(const __optional_move_assign_base& __opt) = default;
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_move_assign_base(__optional_move_assign_base&&) = default;
+    _LIBCPP_INLINE_VISIBILITY
+    __optional_move_assign_base& operator=(const __optional_move_assign_base&) = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 __optional_move_assign_base& operator=(__optional_move_assign_base&& __opt)
+        noexcept(is_nothrow_move_assignable_v<value_type> &&
+                 is_nothrow_move_constructible_v<value_type>)
+    {
+        this->__assign_from(_VSTD::move(__opt));
+        return *this;
+    }
+};
+
+template <class _Tp>
+using __optional_sfinae_ctor_base_t = __sfinae_ctor_base<
+    is_copy_constructible<_Tp>::value,
+    is_move_constructible<_Tp>::value
+>;
+
+template <class _Tp>
+using __optional_sfinae_assign_base_t = __sfinae_assign_base<
+    (is_copy_constructible<_Tp>::value && is_copy_assignable<_Tp>::value),
+    (is_move_constructible<_Tp>::value && is_move_assignable<_Tp>::value)
+>;
+
+template <class _Tp>
+class optional
+    : private __optional_move_assign_base<_Tp>
+    , private __optional_sfinae_ctor_base_t<_Tp>
+    , private __optional_sfinae_assign_base_t<_Tp>
+{
+    using __base = __optional_move_assign_base<_Tp>;
+public:
+    using value_type = _Tp;
+
+private:
+     // Disable the reference extension using this static assert.
+    static_assert(!is_same_v<__uncvref_t<value_type>, in_place_t>,
+        "instantiation of optional with in_place_t is ill-formed");
+    static_assert(!is_same_v<__uncvref_t<value_type>, nullopt_t>,
+        "instantiation of optional with nullopt_t is ill-formed");
+    static_assert(!is_reference_v<value_type>,
+        "instantiation of optional with a reference type is ill-formed");
+    static_assert(is_destructible_v<value_type>,
+        "instantiation of optional with a non-destructible type is ill-formed");
+    static_assert(!is_array_v<value_type>,
+        "instantiation of optional with an array type is ill-formed");
+
+    // LWG2756: conditionally explicit conversion from _Up
+    struct _CheckOptionalArgsConstructor {
+      template <class _Up>
+      static constexpr bool __enable_implicit =
+          is_constructible_v<_Tp, _Up&&> &&
+          is_convertible_v<_Up&&, _Tp>;
+
+      template <class _Up>
+      static constexpr bool __enable_explicit =
+          is_constructible_v<_Tp, _Up&&> &&
+          !is_convertible_v<_Up&&, _Tp>;
+    };
+    template <class _Up>
+    using _CheckOptionalArgsCtor = _If<
+        _IsNotSame<__uncvref_t<_Up>, in_place_t>::value &&
+        _IsNotSame<__uncvref_t<_Up>, optional>::value,
+        _CheckOptionalArgsConstructor,
+        __check_tuple_constructor_fail
+    >;
+    template <class _QualUp>
+    struct _CheckOptionalLikeConstructor {
+      template <class _Up, class _Opt = optional<_Up>>
+      using __check_constructible_from_opt = _Or<
+          is_constructible<_Tp, _Opt&>,
+          is_constructible<_Tp, _Opt const&>,
+          is_constructible<_Tp, _Opt&&>,
+          is_constructible<_Tp, _Opt const&&>,
+          is_convertible<_Opt&, _Tp>,
+          is_convertible<_Opt const&, _Tp>,
+          is_convertible<_Opt&&, _Tp>,
+          is_convertible<_Opt const&&, _Tp>
+      >;
+      template <class _Up, class _Opt = optional<_Up>>
+      using __check_assignable_from_opt = _Or<
+          is_assignable<_Tp&, _Opt&>,
+          is_assignable<_Tp&, _Opt const&>,
+          is_assignable<_Tp&, _Opt&&>,
+          is_assignable<_Tp&, _Opt const&&>
+      >;
+      template <class _Up, class _QUp = _QualUp>
+      static constexpr bool __enable_implicit =
+          is_convertible<_QUp, _Tp>::value &&
+          !__check_constructible_from_opt<_Up>::value;
+
+      template <class _Up, class _QUp = _QualUp>
+      static constexpr bool __enable_explicit =
+          !is_convertible<_QUp, _Tp>::value &&
+          !__check_constructible_from_opt<_Up>::value;
+
+      template <class _Up, class _QUp = _QualUp>
+      static constexpr bool __enable_assign =
+          !__check_constructible_from_opt<_Up>::value &&
+          !__check_assignable_from_opt<_Up>::value;
+    };
+
+    template <class _Up, class _QualUp>
+    using _CheckOptionalLikeCtor = _If<
+      _And<
+         _IsNotSame<_Up, _Tp>,
+          is_constructible<_Tp, _QualUp>
+      >::value,
+      _CheckOptionalLikeConstructor<_QualUp>,
+      __check_tuple_constructor_fail
+    >;
+    template <class _Up, class _QualUp>
+    using _CheckOptionalLikeAssign = _If<
+      _And<
+          _IsNotSame<_Up, _Tp>,
+          is_constructible<_Tp, _QualUp>,
+          is_assignable<_Tp&, _QualUp>
+      >::value,
+      _CheckOptionalLikeConstructor<_QualUp>,
+      __check_tuple_constructor_fail
+    >;
+public:
+
+    _LIBCPP_INLINE_VISIBILITY constexpr optional() noexcept {}
+    _LIBCPP_INLINE_VISIBILITY constexpr optional(const optional&) = default;
+    _LIBCPP_INLINE_VISIBILITY constexpr optional(optional&&) = default;
+    _LIBCPP_INLINE_VISIBILITY constexpr optional(nullopt_t) noexcept {}
+
+    template <class _InPlaceT, class... _Args, class = enable_if_t<
+          _And<
+              _IsSame<_InPlaceT, in_place_t>,
+            is_constructible<value_type, _Args...>
+            >::value
+        >
+    >
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit optional(_InPlaceT, _Args&&... __args)
+        : __base(in_place, _VSTD::forward<_Args>(__args)...) {}
+
+    template <class _Up, class... _Args, class = enable_if_t<
+        is_constructible_v<value_type, initializer_list<_Up>&, _Args...>>
+    >
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit optional(in_place_t, initializer_list<_Up> __il, _Args&&... __args)
+        : __base(in_place, __il, _VSTD::forward<_Args>(__args)...) {}
+
+    template <class _Up = value_type, enable_if_t<
+        _CheckOptionalArgsCtor<_Up>::template __enable_implicit<_Up>
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr optional(_Up&& __v)
+        : __base(in_place, _VSTD::forward<_Up>(__v)) {}
+
+    template <class _Up, enable_if_t<
+        _CheckOptionalArgsCtor<_Up>::template __enable_explicit<_Up>
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit optional(_Up&& __v)
+        : __base(in_place, _VSTD::forward<_Up>(__v)) {}
+
+    // LWG2756: conditionally explicit conversion from const optional<_Up>&
+    template <class _Up, enable_if_t<
+        _CheckOptionalLikeCtor<_Up, _Up const&>::template __enable_implicit<_Up>
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 optional(const optional<_Up>& __v)
+    {
+        this->__construct_from(__v);
+    }
+    template <class _Up, enable_if_t<
+        _CheckOptionalLikeCtor<_Up, _Up const&>::template __enable_explicit<_Up>
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 explicit optional(const optional<_Up>& __v)
+    {
+        this->__construct_from(__v);
+    }
+
+    // LWG2756: conditionally explicit conversion from optional<_Up>&&
+    template <class _Up, enable_if_t<
+        _CheckOptionalLikeCtor<_Up, _Up &&>::template __enable_implicit<_Up>
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 optional(optional<_Up>&& __v)
+    {
+        this->__construct_from(_VSTD::move(__v));
+    }
+    template <class _Up, enable_if_t<
+        _CheckOptionalLikeCtor<_Up, _Up &&>::template __enable_explicit<_Up>
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 explicit optional(optional<_Up>&& __v)
+    {
+        this->__construct_from(_VSTD::move(__v));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 optional& operator=(nullopt_t) noexcept
+    {
+        reset();
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY optional& operator=(const optional&) = default;
+    _LIBCPP_INLINE_VISIBILITY optional& operator=(optional&&) = default;
+
+    // LWG2756
+    template <class _Up = value_type,
+              class = enable_if_t<
+                      _And<
+                          _IsNotSame<__uncvref_t<_Up>, optional>,
+                          _Or<
+                              _IsNotSame<__uncvref_t<_Up>, value_type>,
+                              _Not<is_scalar<value_type>>
+                          >,
+                          is_constructible<value_type, _Up>,
+                          is_assignable<value_type&, _Up>
+                      >::value>
+             >
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 optional&
+    operator=(_Up&& __v)
+    {
+        if (this->has_value())
+            this->__get() = _VSTD::forward<_Up>(__v);
+        else
+            this->__construct(_VSTD::forward<_Up>(__v));
+        return *this;
+    }
+
+    // LWG2756
+    template <class _Up, enable_if_t<
+        _CheckOptionalLikeAssign<_Up, _Up const&>::template __enable_assign<_Up>
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 optional&
+    operator=(const optional<_Up>& __v)
+    {
+        this->__assign_from(__v);
+        return *this;
+    }
+
+    // LWG2756
+    template <class _Up, enable_if_t<
+        _CheckOptionalLikeCtor<_Up, _Up &&>::template __enable_assign<_Up>
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 optional&
+    operator=(optional<_Up>&& __v)
+    {
+        this->__assign_from(_VSTD::move(__v));
+        return *this;
+    }
+
+    template <class... _Args,
+              class = enable_if_t
+                      <
+                          is_constructible_v<value_type, _Args...>
+                      >
+             >
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 _Tp &
+    emplace(_Args&&... __args)
+    {
+        reset();
+        this->__construct(_VSTD::forward<_Args>(__args)...);
+        return this->__get();
+    }
+
+    template <class _Up, class... _Args,
+              class = enable_if_t
+                      <
+                          is_constructible_v<value_type, initializer_list<_Up>&, _Args...>
+                      >
+             >
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 _Tp &
+    emplace(initializer_list<_Up> __il, _Args&&... __args)
+    {
+        reset();
+        this->__construct(__il, _VSTD::forward<_Args>(__args)...);
+        return this->__get();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX17 void swap(optional& __opt)
+        noexcept(is_nothrow_move_constructible_v<value_type> &&
+                 is_nothrow_swappable_v<value_type>)
+    {
+        if (this->has_value() == __opt.has_value())
+        {
+            using _VSTD::swap;
+            if (this->has_value())
+                swap(this->__get(), __opt.__get());
+        }
+        else
+        {
+            if (this->has_value())
+            {
+                __opt.__construct(_VSTD::move(this->__get()));
+                reset();
+            }
+            else
+            {
+                this->__construct(_VSTD::move(__opt.__get()));
+                __opt.reset();
+            }
+        }
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr
+    add_pointer_t<value_type const>
+    operator->() const
+    {
+        _LIBCPP_ASSERT(this->has_value(), "optional operator-> called on a disengaged value");
+        return _VSTD::addressof(this->__get());
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr
+    add_pointer_t<value_type>
+    operator->()
+    {
+        _LIBCPP_ASSERT(this->has_value(), "optional operator-> called on a disengaged value");
+        return _VSTD::addressof(this->__get());
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr
+    const value_type&
+    operator*() const& noexcept
+    {
+        _LIBCPP_ASSERT(this->has_value(), "optional operator* called on a disengaged value");
+        return this->__get();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr
+    value_type&
+    operator*() & noexcept
+    {
+        _LIBCPP_ASSERT(this->has_value(), "optional operator* called on a disengaged value");
+        return this->__get();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr
+    value_type&&
+    operator*() && noexcept
+    {
+        _LIBCPP_ASSERT(this->has_value(), "optional operator* called on a disengaged value");
+        return _VSTD::move(this->__get());
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr
+    const value_type&&
+    operator*() const&& noexcept
+    {
+        _LIBCPP_ASSERT(this->has_value(), "optional operator* called on a disengaged value");
+        return _VSTD::move(this->__get());
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit operator bool() const noexcept { return has_value(); }
+
+    using __base::has_value;
+    using __base::__get;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS
+    constexpr value_type const& value() const&
+    {
+        if (!this->has_value())
+            __throw_bad_optional_access();
+        return this->__get();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS
+    constexpr value_type& value() &
+    {
+        if (!this->has_value())
+            __throw_bad_optional_access();
+        return this->__get();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS
+    constexpr value_type&& value() &&
+    {
+        if (!this->has_value())
+            __throw_bad_optional_access();
+        return _VSTD::move(this->__get());
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS
+    constexpr value_type const&& value() const&&
+    {
+        if (!this->has_value())
+            __throw_bad_optional_access();
+        return _VSTD::move(this->__get());
+    }
+
+    template <class _Up>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr value_type value_or(_Up&& __v) const&
+    {
+        static_assert(is_copy_constructible_v<value_type>,
+                      "optional<T>::value_or: T must be copy constructible");
+        static_assert(is_convertible_v<_Up, value_type>,
+                      "optional<T>::value_or: U must be convertible to T");
+        return this->has_value() ? this->__get() :
+                                  static_cast<value_type>(_VSTD::forward<_Up>(__v));
+    }
+
+    template <class _Up>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr value_type value_or(_Up&& __v) &&
+    {
+        static_assert(is_move_constructible_v<value_type>,
+                      "optional<T>::value_or: T must be move constructible");
+        static_assert(is_convertible_v<_Up, value_type>,
+                      "optional<T>::value_or: U must be convertible to T");
+        return this->has_value() ? _VSTD::move(this->__get()) :
+                                  static_cast<value_type>(_VSTD::forward<_Up>(__v));
+    }
+
+    using __base::reset;
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class T>
+    optional(T) -> optional<T>;
+#endif
+
+// Comparisons between optionals
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() ==
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator==(const optional<_Tp>& __x, const optional<_Up>& __y)
+{
+    if (static_cast<bool>(__x) != static_cast<bool>(__y))
+        return false;
+    if (!static_cast<bool>(__x))
+        return true;
+    return *__x == *__y;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() !=
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator!=(const optional<_Tp>& __x, const optional<_Up>& __y)
+{
+    if (static_cast<bool>(__x) != static_cast<bool>(__y))
+        return true;
+    if (!static_cast<bool>(__x))
+        return false;
+    return *__x != *__y;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() <
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator<(const optional<_Tp>& __x, const optional<_Up>& __y)
+{
+    if (!static_cast<bool>(__y))
+        return false;
+    if (!static_cast<bool>(__x))
+        return true;
+    return *__x < *__y;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() >
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator>(const optional<_Tp>& __x, const optional<_Up>& __y)
+{
+    if (!static_cast<bool>(__x))
+        return false;
+    if (!static_cast<bool>(__y))
+        return true;
+    return *__x > *__y;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() <=
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator<=(const optional<_Tp>& __x, const optional<_Up>& __y)
+{
+    if (!static_cast<bool>(__x))
+        return true;
+    if (!static_cast<bool>(__y))
+        return false;
+    return *__x <= *__y;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() >=
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator>=(const optional<_Tp>& __x, const optional<_Up>& __y)
+{
+    if (!static_cast<bool>(__y))
+        return true;
+    if (!static_cast<bool>(__x))
+        return false;
+    return *__x >= *__y;
+}
+
+// Comparisons with nullopt
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool
+operator==(const optional<_Tp>& __x, nullopt_t) noexcept
+{
+    return !static_cast<bool>(__x);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool
+operator==(nullopt_t, const optional<_Tp>& __x) noexcept
+{
+    return !static_cast<bool>(__x);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool
+operator!=(const optional<_Tp>& __x, nullopt_t) noexcept
+{
+    return static_cast<bool>(__x);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool
+operator!=(nullopt_t, const optional<_Tp>& __x) noexcept
+{
+    return static_cast<bool>(__x);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool
+operator<(const optional<_Tp>&, nullopt_t) noexcept
+{
+    return false;
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool
+operator<(nullopt_t, const optional<_Tp>& __x) noexcept
+{
+    return static_cast<bool>(__x);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool
+operator<=(const optional<_Tp>& __x, nullopt_t) noexcept
+{
+    return !static_cast<bool>(__x);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool
+operator<=(nullopt_t, const optional<_Tp>&) noexcept
+{
+    return true;
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool
+operator>(const optional<_Tp>& __x, nullopt_t) noexcept
+{
+    return static_cast<bool>(__x);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool
+operator>(nullopt_t, const optional<_Tp>&) noexcept
+{
+    return false;
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool
+operator>=(const optional<_Tp>&, nullopt_t) noexcept
+{
+    return true;
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+bool
+operator>=(nullopt_t, const optional<_Tp>& __x) noexcept
+{
+    return !static_cast<bool>(__x);
+}
+
+// Comparisons with T
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() ==
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator==(const optional<_Tp>& __x, const _Up& __v)
+{
+    return static_cast<bool>(__x) ? *__x == __v : false;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() ==
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator==(const _Tp& __v, const optional<_Up>& __x)
+{
+    return static_cast<bool>(__x) ? __v == *__x : false;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() !=
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator!=(const optional<_Tp>& __x, const _Up& __v)
+{
+    return static_cast<bool>(__x) ? *__x != __v : true;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() !=
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator!=(const _Tp& __v, const optional<_Up>& __x)
+{
+    return static_cast<bool>(__x) ? __v != *__x : true;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() <
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator<(const optional<_Tp>& __x, const _Up& __v)
+{
+    return static_cast<bool>(__x) ? *__x < __v : true;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() <
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator<(const _Tp& __v, const optional<_Up>& __x)
+{
+    return static_cast<bool>(__x) ? __v < *__x : false;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() <=
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator<=(const optional<_Tp>& __x, const _Up& __v)
+{
+    return static_cast<bool>(__x) ? *__x <= __v : true;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() <=
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator<=(const _Tp& __v, const optional<_Up>& __x)
+{
+    return static_cast<bool>(__x) ? __v <= *__x : false;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() >
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator>(const optional<_Tp>& __x, const _Up& __v)
+{
+    return static_cast<bool>(__x) ? *__x > __v : false;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() >
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator>(const _Tp& __v, const optional<_Up>& __x)
+{
+    return static_cast<bool>(__x) ? __v > *__x : true;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() >=
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator>=(const optional<_Tp>& __x, const _Up& __v)
+{
+    return static_cast<bool>(__x) ? *__x >= __v : false;
+}
+
+template <class _Tp, class _Up>
+_LIBCPP_INLINE_VISIBILITY constexpr
+enable_if_t<
+    is_convertible_v<decltype(declval<const _Tp&>() >=
+        declval<const _Up&>()), bool>,
+    bool
+>
+operator>=(const _Tp& __v, const optional<_Up>& __x)
+{
+    return static_cast<bool>(__x) ? __v >= *__x : true;
+}
+
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+enable_if_t<
+    is_move_constructible_v<_Tp> && is_swappable_v<_Tp>,
+    void
+>
+swap(optional<_Tp>& __x, optional<_Tp>& __y) noexcept(noexcept(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY constexpr
+optional<decay_t<_Tp>> make_optional(_Tp&& __v)
+{
+    return optional<decay_t<_Tp>>(_VSTD::forward<_Tp>(__v));
+}
+
+template <class _Tp, class... _Args>
+_LIBCPP_INLINE_VISIBILITY constexpr
+optional<_Tp> make_optional(_Args&&... __args)
+{
+    return optional<_Tp>(in_place, _VSTD::forward<_Args>(__args)...);
+}
+
+template <class _Tp, class _Up, class... _Args>
+_LIBCPP_INLINE_VISIBILITY constexpr
+optional<_Tp> make_optional(initializer_list<_Up> __il,  _Args&&... __args)
+{
+    return optional<_Tp>(in_place, __il, _VSTD::forward<_Args>(__args)...);
+}
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS hash<
+    __enable_hash_helper<optional<_Tp>, remove_const_t<_Tp>>
+>
+{
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef optional<_Tp> argument_type;
+    _LIBCPP_DEPRECATED_IN_CXX17 typedef size_t        result_type;
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const optional<_Tp>& __opt) const
+    {
+        return static_cast<bool>(__opt) ? hash<remove_const_t<_Tp>>()(*__opt) : 0;
+    }
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER > 14
+
+#endif // _LIBCPP_OPTIONAL
diff --git a/contrib/libs/cxxsupp/libcxx/include/ostream b/contrib/libs/cxxsupp/libcxx/include/ostream
new file mode 100644
index 00000000000..e0aa18fa481
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/ostream
@@ -0,0 +1,1096 @@
+// -*- C++ -*-
+//===-------------------------- ostream -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_OSTREAM
+#define _LIBCPP_OSTREAM
+
+/*
+    ostream synopsis
+
+template <class charT, class traits = char_traits<charT> >
+class basic_ostream
+    : virtual public basic_ios<charT,traits>
+{
+public:
+    // types (inherited from basic_ios (27.5.4)):
+    typedef charT                          char_type;
+    typedef traits                         traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    // 27.7.2.2 Constructor/destructor:
+    explicit basic_ostream(basic_streambuf<char_type,traits>* sb);
+    basic_ostream(basic_ostream&& rhs);
+    virtual ~basic_ostream();
+
+    // 27.7.2.3 Assign/swap
+    basic_ostream& operator=(const basic_ostream& rhs) = delete; // C++14
+    basic_ostream& operator=(basic_ostream&& rhs);
+    void swap(basic_ostream& rhs);
+
+    // 27.7.2.4 Prefix/suffix:
+    class sentry;
+
+    // 27.7.2.6 Formatted output:
+    basic_ostream& operator<<(basic_ostream& (*pf)(basic_ostream&));
+    basic_ostream& operator<<(basic_ios<charT, traits>& (*pf)(basic_ios<charT,traits>&));
+    basic_ostream& operator<<(ios_base& (*pf)(ios_base&));
+    basic_ostream& operator<<(bool n);
+    basic_ostream& operator<<(short n);
+    basic_ostream& operator<<(unsigned short n);
+    basic_ostream& operator<<(int n);
+    basic_ostream& operator<<(unsigned int n);
+    basic_ostream& operator<<(long n);
+    basic_ostream& operator<<(unsigned long n);
+    basic_ostream& operator<<(long long n);
+    basic_ostream& operator<<(unsigned long long n);
+    basic_ostream& operator<<(float f);
+    basic_ostream& operator<<(double f);
+    basic_ostream& operator<<(long double f);
+    basic_ostream& operator<<(const void* p);
+    basic_ostream& operator<<(basic_streambuf<char_type,traits>* sb);
+    basic_ostream& operator<<(nullptr_t);
+
+    // 27.7.2.7 Unformatted output:
+    basic_ostream& put(char_type c);
+    basic_ostream& write(const char_type* s, streamsize n);
+    basic_ostream& flush();
+
+    // 27.7.2.5 seeks:
+    pos_type tellp();
+    basic_ostream& seekp(pos_type);
+    basic_ostream& seekp(off_type, ios_base::seekdir);
+protected:
+    basic_ostream(const basic_ostream& rhs) = delete;
+    basic_ostream(basic_ostream&& rhs);
+    // 27.7.3.3 Assign/swap
+    basic_ostream& operator=(basic_ostream& rhs) = delete;
+    basic_ostream& operator=(const basic_ostream&& rhs);
+    void swap(basic_ostream& rhs);
+};
+
+// 27.7.2.6.4 character inserters
+
+template<class charT, class traits>
+  basic_ostream<charT,traits>& operator<<(basic_ostream<charT,traits>&, charT);
+
+template<class charT, class traits>
+  basic_ostream<charT,traits>& operator<<(basic_ostream<charT,traits>&, char);
+
+template<class traits>
+  basic_ostream<char,traits>& operator<<(basic_ostream<char,traits>&, char);
+
+// signed and unsigned
+
+template<class traits>
+  basic_ostream<char,traits>& operator<<(basic_ostream<char,traits>&, signed char);
+
+template<class traits>
+  basic_ostream<char,traits>& operator<<(basic_ostream<char,traits>&, unsigned char);
+
+// NTBS
+template<class charT, class traits>
+  basic_ostream<charT,traits>& operator<<(basic_ostream<charT,traits>&, const charT*);
+
+template<class charT, class traits>
+  basic_ostream<charT,traits>& operator<<(basic_ostream<charT,traits>&, const char*);
+
+template<class traits>
+  basic_ostream<char,traits>& operator<<(basic_ostream<char,traits>&, const char*);
+
+// signed and unsigned
+template<class traits>
+basic_ostream<char,traits>& operator<<(basic_ostream<char,traits>&, const signed char*);
+
+template<class traits>
+  basic_ostream<char,traits>& operator<<(basic_ostream<char,traits>&, const unsigned char*);
+
+// swap:
+template <class charT, class traits>
+  void swap(basic_ostream<charT, traits>& x, basic_ostream<charT, traits>& y);
+
+template <class charT, class traits>
+  basic_ostream<charT,traits>& endl(basic_ostream<charT,traits>& os);
+
+template <class charT, class traits>
+  basic_ostream<charT,traits>& ends(basic_ostream<charT,traits>& os);
+
+template <class charT, class traits>
+  basic_ostream<charT,traits>& flush(basic_ostream<charT,traits>& os);
+
+// rvalue stream insertion
+template <class Stream, class T>
+  Stream&& operator<<(Stream&& os, const T& x);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <bitset>
+#include <ios>
+#include <iterator>
+#include <locale>
+#include <streambuf>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _CharT, class _Traits>
+class _LIBCPP_TEMPLATE_VIS basic_ostream
+    : virtual public basic_ios<_CharT, _Traits>
+{
+public:
+    // types (inherited from basic_ios (27.5.4)):
+    typedef _CharT                         char_type;
+    typedef _Traits                        traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    // 27.7.2.2 Constructor/destructor:
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    explicit basic_ostream(basic_streambuf<char_type, traits_type>* __sb)
+    { this->init(__sb); }
+    virtual ~basic_ostream();
+protected:
+    inline _LIBCPP_INLINE_VISIBILITY
+    basic_ostream(basic_ostream&& __rhs);
+
+    // 27.7.2.3 Assign/swap
+    inline _LIBCPP_INLINE_VISIBILITY
+    basic_ostream& operator=(basic_ostream&& __rhs);
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    void swap(basic_ostream& __rhs)
+    { basic_ios<char_type, traits_type>::swap(__rhs); }
+
+    basic_ostream           (const basic_ostream& __rhs) = delete;
+    basic_ostream& operator=(const basic_ostream& __rhs) = delete;
+
+public:
+    // 27.7.2.4 Prefix/suffix:
+    class _LIBCPP_TEMPLATE_VIS sentry;
+
+    // 27.7.2.6 Formatted output:
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    basic_ostream& operator<<(basic_ostream& (*__pf)(basic_ostream&))
+    { return __pf(*this); }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    basic_ostream& operator<<(basic_ios<char_type, traits_type>&
+                              (*__pf)(basic_ios<char_type,traits_type>&))
+    { __pf(*this); return *this; }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    basic_ostream& operator<<(ios_base& (*__pf)(ios_base&))
+    { __pf(*this); return *this; }
+
+    basic_ostream& operator<<(bool __n);
+    basic_ostream& operator<<(short __n);
+    basic_ostream& operator<<(unsigned short __n);
+    basic_ostream& operator<<(int __n);
+    basic_ostream& operator<<(unsigned int __n);
+    basic_ostream& operator<<(long __n);
+    basic_ostream& operator<<(unsigned long __n);
+    basic_ostream& operator<<(long long __n);
+    basic_ostream& operator<<(unsigned long long __n);
+    basic_ostream& operator<<(float __f);
+    basic_ostream& operator<<(double __f);
+    basic_ostream& operator<<(long double __f);
+    basic_ostream& operator<<(const void* __p);
+    basic_ostream& operator<<(basic_streambuf<char_type, traits_type>* __sb);
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ostream& operator<<(nullptr_t)
+    { return *this << "nullptr"; }
+
+    // 27.7.2.7 Unformatted output:
+    basic_ostream& put(char_type __c);
+    basic_ostream& write(const char_type* __s, streamsize __n);
+    basic_ostream& flush();
+
+    // 27.7.2.5 seeks:
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    pos_type tellp();
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    basic_ostream& seekp(pos_type __pos);
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    basic_ostream& seekp(off_type __off, ios_base::seekdir __dir);
+
+protected:
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ostream() {}  // extension, intentially does not initialize
+};
+
+template <class _CharT, class _Traits>
+class _LIBCPP_TEMPLATE_VIS basic_ostream<_CharT, _Traits>::sentry
+{
+    bool __ok_;
+    basic_ostream<_CharT, _Traits>& __os_;
+
+    sentry(const sentry&); // = delete;
+    sentry& operator=(const sentry&); // = delete;
+
+public:
+    explicit sentry(basic_ostream<_CharT, _Traits>& __os);
+    ~sentry();
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit operator bool() const {return __ok_;}
+};
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>::sentry::sentry(basic_ostream<_CharT, _Traits>& __os)
+    : __ok_(false),
+      __os_(__os)
+{
+    if (__os.good())
+    {
+        if (__os.tie())
+            __os.tie()->flush();
+        __ok_ = true;
+    }
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>::sentry::~sentry()
+{
+    if (__os_.rdbuf() && __os_.good() && (__os_.flags() & ios_base::unitbuf)
+                      && !uncaught_exception())
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            if (__os_.rdbuf()->pubsync() == -1)
+                __os_.setstate(ios_base::badbit);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>::basic_ostream(basic_ostream&& __rhs)
+{
+    this->move(__rhs);
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator=(basic_ostream&& __rhs)
+{
+    swap(__rhs);
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>::~basic_ostream()
+{
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(basic_streambuf<char_type, traits_type>* __sb)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            if (__sb)
+            {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+                try
+                {
+#endif // _LIBCPP_NO_EXCEPTIONS
+                    typedef istreambuf_iterator<_CharT, _Traits> _Ip;
+                    typedef ostreambuf_iterator<_CharT, _Traits> _Op;
+                    _Ip __i(__sb);
+                    _Ip __eof;
+                    _Op __o(*this);
+                    size_t __c = 0;
+                    for (; __i != __eof; ++__i, ++__o, ++__c)
+                    {
+                        *__o = *__i;
+                        if (__o.failed())
+                            break;
+                    }
+                    if (__c == 0)
+                        this->setstate(ios_base::failbit);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+                }
+                catch (...)
+                {
+                    this->__set_failbit_and_consider_rethrow();
+                }
+#endif // _LIBCPP_NO_EXCEPTIONS
+            }
+            else
+                this->setstate(ios_base::badbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(bool __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            typedef num_put<char_type, ostreambuf_iterator<char_type, traits_type> > _Fp;
+            const _Fp& __f = use_facet<_Fp>(this->getloc());
+            if (__f.put(*this, *this, this->fill(), __n).failed())
+                this->setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(short __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            ios_base::fmtflags __flags = ios_base::flags() & ios_base::basefield;
+            typedef num_put<char_type, ostreambuf_iterator<char_type, traits_type> > _Fp;
+            const _Fp& __f = use_facet<_Fp>(this->getloc());
+            if (__f.put(*this, *this, this->fill(),
+                        __flags == ios_base::oct || __flags == ios_base::hex ?
+                        static_cast<long>(static_cast<unsigned short>(__n))  :
+                        static_cast<long>(__n)).failed())
+                this->setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(unsigned short __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            typedef num_put<char_type, ostreambuf_iterator<char_type, traits_type> > _Fp;
+            const _Fp& __f = use_facet<_Fp>(this->getloc());
+            if (__f.put(*this, *this, this->fill(), static_cast<unsigned long>(__n)).failed())
+                this->setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(int __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            ios_base::fmtflags __flags = ios_base::flags() & ios_base::basefield;
+            typedef num_put<char_type, ostreambuf_iterator<char_type, traits_type> > _Fp;
+            const _Fp& __f = use_facet<_Fp>(this->getloc());
+            if (__f.put(*this, *this, this->fill(),
+                        __flags == ios_base::oct || __flags == ios_base::hex ?
+                        static_cast<long>(static_cast<unsigned int>(__n))  :
+                        static_cast<long>(__n)).failed())
+                this->setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(unsigned int __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            typedef num_put<char_type, ostreambuf_iterator<char_type, traits_type> > _Fp;
+            const _Fp& __f = use_facet<_Fp>(this->getloc());
+            if (__f.put(*this, *this, this->fill(), static_cast<unsigned long>(__n)).failed())
+                this->setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(long __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            typedef num_put<char_type, ostreambuf_iterator<char_type, traits_type> > _Fp;
+            const _Fp& __f = use_facet<_Fp>(this->getloc());
+            if (__f.put(*this, *this, this->fill(), __n).failed())
+                this->setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(unsigned long __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            typedef num_put<char_type, ostreambuf_iterator<char_type, traits_type> > _Fp;
+            const _Fp& __f = use_facet<_Fp>(this->getloc());
+            if (__f.put(*this, *this, this->fill(), __n).failed())
+                this->setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(long long __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            typedef num_put<char_type, ostreambuf_iterator<char_type, traits_type> > _Fp;
+            const _Fp& __f = use_facet<_Fp>(this->getloc());
+            if (__f.put(*this, *this, this->fill(), __n).failed())
+                this->setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(unsigned long long __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            typedef num_put<char_type, ostreambuf_iterator<char_type, traits_type> > _Fp;
+            const _Fp& __f = use_facet<_Fp>(this->getloc());
+            if (__f.put(*this, *this, this->fill(), __n).failed())
+                this->setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(float __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            typedef num_put<char_type, ostreambuf_iterator<char_type, traits_type> > _Fp;
+            const _Fp& __f = use_facet<_Fp>(this->getloc());
+            if (__f.put(*this, *this, this->fill(), static_cast<double>(__n)).failed())
+                this->setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(double __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            typedef num_put<char_type, ostreambuf_iterator<char_type, traits_type> > _Fp;
+            const _Fp& __f = use_facet<_Fp>(this->getloc());
+            if (__f.put(*this, *this, this->fill(), __n).failed())
+                this->setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(long double __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            typedef num_put<char_type, ostreambuf_iterator<char_type, traits_type> > _Fp;
+            const _Fp& __f = use_facet<_Fp>(this->getloc());
+            if (__f.put(*this, *this, this->fill(), __n).failed())
+                this->setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::operator<<(const void* __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            typedef num_put<char_type, ostreambuf_iterator<char_type, traits_type> > _Fp;
+            const _Fp& __f = use_facet<_Fp>(this->getloc());
+            if (__f.put(*this, *this, this->fill(), __n).failed())
+                this->setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template<class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+__put_character_sequence(basic_ostream<_CharT, _Traits>& __os,
+                          const _CharT* __str, size_t __len)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        typename basic_ostream<_CharT, _Traits>::sentry __s(__os);
+        if (__s)
+        {
+            typedef ostreambuf_iterator<_CharT, _Traits> _Ip;
+            if (__pad_and_output(_Ip(__os),
+                                 __str,
+                                 (__os.flags() & ios_base::adjustfield) == ios_base::left ?
+                                     __str + __len :
+                                     __str,
+                                 __str + __len,
+                                 __os,
+                                 __os.fill()).failed())
+                __os.setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __os.__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return __os;
+}
+
+
+template<class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, _CharT __c)
+{
+    return _VSTD::__put_character_sequence(__os, &__c, 1);
+}
+
+template<class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, char __cn)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        typename basic_ostream<_CharT, _Traits>::sentry __s(__os);
+        if (__s)
+        {
+            _CharT __c = __os.widen(__cn);
+            typedef ostreambuf_iterator<_CharT, _Traits> _Ip;
+            if (__pad_and_output(_Ip(__os),
+                                 &__c,
+                                 (__os.flags() & ios_base::adjustfield) == ios_base::left ?
+                                     &__c + 1 :
+                                     &__c,
+                                 &__c + 1,
+                                 __os,
+                                 __os.fill()).failed())
+                __os.setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __os.__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return __os;
+}
+
+template<class _Traits>
+basic_ostream<char, _Traits>&
+operator<<(basic_ostream<char, _Traits>& __os, char __c)
+{
+    return _VSTD::__put_character_sequence(__os, &__c, 1);
+}
+
+template<class _Traits>
+basic_ostream<char, _Traits>&
+operator<<(basic_ostream<char, _Traits>& __os, signed char __c)
+{
+    return _VSTD::__put_character_sequence(__os, (char *) &__c, 1);
+}
+
+template<class _Traits>
+basic_ostream<char, _Traits>&
+operator<<(basic_ostream<char, _Traits>& __os, unsigned char __c)
+{
+    return _VSTD::__put_character_sequence(__os, (char *) &__c, 1);
+}
+
+template<class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const _CharT* __str)
+{
+    return _VSTD::__put_character_sequence(__os, __str, _Traits::length(__str));
+}
+
+template<class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const char* __strn)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        typename basic_ostream<_CharT, _Traits>::sentry __s(__os);
+        if (__s)
+        {
+            typedef ostreambuf_iterator<_CharT, _Traits> _Ip;
+            size_t __len = char_traits<char>::length(__strn);
+            const int __bs = 100;
+            _CharT __wbb[__bs];
+            _CharT* __wb = __wbb;
+            unique_ptr<_CharT, void(*)(void*)> __h(0, free);
+            if (__len > __bs)
+            {
+                __wb = (_CharT*)malloc(__len*sizeof(_CharT));
+                if (__wb == 0)
+                    __throw_bad_alloc();
+                __h.reset(__wb);
+            }
+            for (_CharT* __p = __wb; *__strn != '\0'; ++__strn, ++__p)
+                *__p = __os.widen(*__strn);
+            if (__pad_and_output(_Ip(__os),
+                                 __wb,
+                                 (__os.flags() & ios_base::adjustfield) == ios_base::left ?
+                                     __wb + __len :
+                                     __wb,
+                                 __wb + __len,
+                                 __os,
+                                 __os.fill()).failed())
+                __os.setstate(ios_base::badbit | ios_base::failbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        __os.__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return __os;
+}
+
+template<class _Traits>
+basic_ostream<char, _Traits>&
+operator<<(basic_ostream<char, _Traits>& __os, const char* __str)
+{
+    return _VSTD::__put_character_sequence(__os, __str, _Traits::length(__str));
+}
+
+template<class _Traits>
+basic_ostream<char, _Traits>&
+operator<<(basic_ostream<char, _Traits>& __os, const signed char* __str)
+{
+    const char *__s = (const char *) __str;
+    return _VSTD::__put_character_sequence(__os, __s, _Traits::length(__s));
+}
+
+template<class _Traits>
+basic_ostream<char, _Traits>&
+operator<<(basic_ostream<char, _Traits>& __os, const unsigned char* __str)
+{
+    const char *__s = (const char *) __str;
+    return _VSTD::__put_character_sequence(__os, __s, _Traits::length(__s));
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::put(char_type __c)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __s(*this);
+        if (__s)
+        {
+            typedef ostreambuf_iterator<_CharT, _Traits> _Op;
+            _Op __o(*this);
+            *__o = __c;
+            if (__o.failed())
+                this->setstate(ios_base::badbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::write(const char_type* __s, streamsize __n)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        sentry __sen(*this);
+        if (__sen && __n)
+        {
+            if (this->rdbuf()->sputn(__s, __n) != __n)
+                this->setstate(ios_base::badbit);
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::flush()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        if (this->rdbuf())
+        {
+            sentry __s(*this);
+            if (__s)
+            {
+                if (this->rdbuf()->pubsync() == -1)
+                    this->setstate(ios_base::badbit);
+            }
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        this->__set_badbit_and_consider_rethrow();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+typename basic_ostream<_CharT, _Traits>::pos_type
+basic_ostream<_CharT, _Traits>::tellp()
+{
+    if (this->fail())
+        return pos_type(-1);
+    return this->rdbuf()->pubseekoff(0, ios_base::cur, ios_base::out);
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::seekp(pos_type __pos)
+{
+    sentry __s(*this);
+    if (!this->fail())
+    {
+        if (this->rdbuf()->pubseekpos(__pos, ios_base::out) == pos_type(-1))
+            this->setstate(ios_base::failbit);
+    }
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+basic_ostream<_CharT, _Traits>::seekp(off_type __off, ios_base::seekdir __dir)
+{
+    sentry __s(*this);
+    if (!this->fail())
+    {
+        if (this->rdbuf()->pubseekoff(__off, __dir, ios_base::out) == pos_type(-1))
+            this->setstate(ios_base::failbit);
+    }
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_ostream<_CharT, _Traits>&
+endl(basic_ostream<_CharT, _Traits>& __os)
+{
+    __os.put(__os.widen('\n'));
+    __os.flush();
+    return __os;
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_ostream<_CharT, _Traits>&
+ends(basic_ostream<_CharT, _Traits>& __os)
+{
+    __os.put(_CharT());
+    return __os;
+}
+
+template <class _CharT, class _Traits>
+inline
+basic_ostream<_CharT, _Traits>&
+flush(basic_ostream<_CharT, _Traits>& __os)
+{
+    __os.flush();
+    return __os;
+}
+
+template <class _Stream, class _Tp, class = void>
+struct __is_ostreamable : false_type { };
+
+template <class _Stream, class _Tp>
+struct __is_ostreamable<_Stream, _Tp, decltype(
+    declval<_Stream>() << declval<_Tp>(), void()
+)> : true_type { };
+
+template <class _Stream, class _Tp, class = typename enable_if<
+    _And<is_base_of<ios_base, _Stream>,
+         __is_ostreamable<_Stream&, const _Tp&> >::value
+>::type>
+_LIBCPP_INLINE_VISIBILITY
+_Stream&& operator<<(_Stream&& __os, const _Tp& __x)
+{
+    __os << __x;
+    return _VSTD::move(__os);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const basic_string<_CharT, _Traits, _Allocator>& __str)
+{
+    return _VSTD::__put_character_sequence(__os, __str.data(), __str.size());
+}
+
+template<class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           basic_string_view<_CharT, _Traits> __sv)
+{
+    return _VSTD::__put_character_sequence(__os, __sv.data(), __sv.size());
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __ec)
+{
+    return __os << __ec.category().name() << ':' << __ec.value();
+}
+
+template<class _CharT, class _Traits, class _Yp>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, shared_ptr<_Yp> const& __p)
+{
+    return __os << __p.get();
+}
+
+template<class _CharT, class _Traits, class _Yp, class _Dp>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    is_same<void, typename __void_t<decltype((declval<basic_ostream<_CharT, _Traits>&>() << declval<typename unique_ptr<_Yp, _Dp>::pointer>()))>::type>::value,
+    basic_ostream<_CharT, _Traits>&
+>::type
+operator<<(basic_ostream<_CharT, _Traits>& __os, unique_ptr<_Yp, _Dp> const& __p)
+{
+    return __os << __p.get();
+}
+
+template <class _CharT, class _Traits, size_t _Size>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const bitset<_Size>& __x)
+{
+    return __os << __x.template to_string<_CharT, _Traits>
+                        (use_facet<ctype<_CharT> >(__os.getloc()).widen('0'),
+                         use_facet<ctype<_CharT> >(__os.getloc()).widen('1'));
+}
+
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ostream<char>)
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ostream<wchar_t>)
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_OSTREAM
diff --git a/contrib/libs/cxxsupp/libcxx/include/queue b/contrib/libs/cxxsupp/libcxx/include/queue
new file mode 100644
index 00000000000..cbd07140a72
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/queue
@@ -0,0 +1,910 @@
+// -*- C++ -*-
+//===--------------------------- queue ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_QUEUE
+#define _LIBCPP_QUEUE
+
+/*
+    queue synopsis
+
+namespace std
+{
+
+template <class T, class Container = deque<T>>
+class queue
+{
+public:
+    typedef Container                                container_type;
+    typedef typename container_type::value_type      value_type;
+    typedef typename container_type::reference       reference;
+    typedef typename container_type::const_reference const_reference;
+    typedef typename container_type::size_type       size_type;
+
+protected:
+    container_type c;
+
+public:
+    queue() = default;
+    ~queue() = default;
+
+    queue(const queue& q) = default;
+    queue(queue&& q) = default;
+
+    queue& operator=(const queue& q) = default;
+    queue& operator=(queue&& q) = default;
+
+    explicit queue(const container_type& c);
+    explicit queue(container_type&& c)
+    template <class Alloc>
+        explicit queue(const Alloc& a);
+    template <class Alloc>
+        queue(const container_type& c, const Alloc& a);
+    template <class Alloc>
+        queue(container_type&& c, const Alloc& a);
+    template <class Alloc>
+        queue(const queue& q, const Alloc& a);
+    template <class Alloc>
+        queue(queue&& q, const Alloc& a);
+
+    bool      empty() const;
+    size_type size() const;
+
+    reference       front();
+    const_reference front() const;
+    reference       back();
+    const_reference back() const;
+
+    void push(const value_type& v);
+    void push(value_type&& v);
+    template <class... Args> reference emplace(Args&&... args); // reference in C++17
+    void pop();
+
+    void swap(queue& q) noexcept(is_nothrow_swappable_v<Container>)
+};
+
+template<class Container>
+  queue(Container) -> queue<typename Container::value_type, Container>; // C++17
+
+template<class Container, class Allocator>
+  queue(Container, Allocator) -> queue<typename Container::value_type, Container>; // C++17
+
+template <class T, class Container>
+  bool operator==(const queue<T, Container>& x,const queue<T, Container>& y);
+
+template <class T, class Container>
+  bool operator< (const queue<T, Container>& x,const queue<T, Container>& y);
+
+template <class T, class Container>
+  bool operator!=(const queue<T, Container>& x,const queue<T, Container>& y);
+
+template <class T, class Container>
+  bool operator> (const queue<T, Container>& x,const queue<T, Container>& y);
+
+template <class T, class Container>
+  bool operator>=(const queue<T, Container>& x,const queue<T, Container>& y);
+
+template <class T, class Container>
+  bool operator<=(const queue<T, Container>& x,const queue<T, Container>& y);
+
+template <class T, class Container>
+  void swap(queue<T, Container>& x, queue<T, Container>& y)
+  noexcept(noexcept(x.swap(y)));
+
+template <class T, class Container = vector<T>,
+          class Compare = less<typename Container::value_type>>
+class priority_queue
+{
+public:
+    typedef Container                                container_type;
+    typedef typename container_type::value_type      value_type;
+    typedef typename container_type::reference       reference;
+    typedef typename container_type::const_reference const_reference;
+    typedef typename container_type::size_type       size_type;
+
+protected:
+    container_type c;
+    Compare comp;
+
+public:
+    priority_queue() : priority_queue(Compare()) {} // C++20
+    explicit priority_queue(const Compare& x) : priority_queue(x, Container()) {}
+    priority_queue(const Compare& x, const Container&);
+    explicit priority_queue(const Compare& x = Compare(), Container&& = Container()); // before C++20
+    priority_queue(const Compare& x, Container&&); // C++20
+    template <class InputIterator>
+        priority_queue(InputIterator first, InputIterator last,
+                       const Compare& comp = Compare());
+    template <class InputIterator>
+        priority_queue(InputIterator first, InputIterator last,
+                       const Compare& comp, const Container& c);
+    template <class InputIterator>
+        priority_queue(InputIterator first, InputIterator last,
+                       const Compare& comp, Container&& c);
+    template <class Alloc>
+        explicit priority_queue(const Alloc& a);
+    template <class Alloc>
+        priority_queue(const Compare& comp, const Alloc& a);
+    template <class Alloc>
+        priority_queue(const Compare& comp, const Container& c,
+                       const Alloc& a);
+    template <class Alloc>
+        priority_queue(const Compare& comp, Container&& c,
+                       const Alloc& a);
+    template <class InputIterator>
+        priority_queue(InputIterator first, InputIterator last,
+                       const Alloc& a);
+    template <class InputIterator>
+        priority_queue(InputIterator first, InputIterator last,
+                       const Compare& comp, const Alloc& a);
+    template <class InputIterator>
+        priority_queue(InputIterator first, InputIterator last,
+                       const Compare& comp, const Container& c, const Alloc& a);
+    template <class InputIterator>
+        priority_queue(InputIterator first, InputIterator last,
+                       const Compare& comp, Container&& c, const Alloc& a);
+    template <class Alloc>
+        priority_queue(const priority_queue& q, const Alloc& a);
+    template <class Alloc>
+        priority_queue(priority_queue&& q, const Alloc& a);
+
+    bool            empty() const;
+    size_type       size() const;
+    const_reference top() const;
+
+    void push(const value_type& v);
+    void push(value_type&& v);
+    template <class... Args> void emplace(Args&&... args);
+    void pop();
+
+    void swap(priority_queue& q)
+        noexcept(is_nothrow_swappable_v<Container> &&
+                 is_nothrow_swappable_v<Comp>)
+};
+
+template <class Compare, class Container>
+priority_queue(Compare, Container)
+    -> priority_queue<typename Container::value_type, Container, Compare>; // C++17
+
+template<class InputIterator,
+         class Compare = less<iter-value-type<InputIterator>>,
+         class Container = vector<iter-value-type<InputIterator>>>
+priority_queue(InputIterator, InputIterator, Compare = Compare(), Container = Container())
+    -> priority_queue<iter-value-type<InputIterator>, Container, Compare>; // C++17
+
+template<class Compare, class Container, class Allocator>
+priority_queue(Compare, Container, Allocator)
+    -> priority_queue<typename Container::value_type, Container, Compare>; // C++17
+
+template<class InputIterator, class Allocator>
+priority_queue(InputIterator, InputIterator, Allocator)
+    -> priority_queue<iter-value-type<InputIterator>,
+                      vector<iter-value-type<InputIterator>, Allocator>,
+                      less<iter-value-type<InputIterator>>>;
+
+template<class InputIterator, class Compare, class Allocator>
+priority_queue(InputIterator, InputIterator, Compare, Allocator)
+    -> priority_queue<iter-value-type<InputIterator>,
+                      vector<iter-value-type<InputIterator>, Allocator>, Compare>;
+
+template<class InputIterator, class Compare, class Container, class Allocator>
+priority_queue(InputIterator, InputIterator, Compare, Container, Allocator)
+    -> priority_queue<typename Container::value_type, Container, Compare>;
+
+template <class T, class Container, class Compare>
+  void swap(priority_queue<T, Container, Compare>& x,
+            priority_queue<T, Container, Compare>& y)
+            noexcept(noexcept(x.swap(y)));
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__memory/uses_allocator.h>
+#include <__utility/forward.h>
+#include <algorithm>
+#include <compare>
+#include <deque>
+#include <functional>
+#include <vector>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class _Container = deque<_Tp> > class _LIBCPP_TEMPLATE_VIS queue;
+
+template <class _Tp, class _Container>
+_LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const queue<_Tp, _Container>& __x,const queue<_Tp, _Container>& __y);
+
+template <class _Tp, class _Container>
+_LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const queue<_Tp, _Container>& __x,const queue<_Tp, _Container>& __y);
+
+template <class _Tp, class _Container /*= deque<_Tp>*/>
+class _LIBCPP_TEMPLATE_VIS queue
+{
+public:
+    typedef _Container                               container_type;
+    typedef typename container_type::value_type      value_type;
+    typedef typename container_type::reference       reference;
+    typedef typename container_type::const_reference const_reference;
+    typedef typename container_type::size_type       size_type;
+    static_assert((is_same<_Tp, value_type>::value), "" );
+
+protected:
+    container_type c;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    queue()
+        _NOEXCEPT_(is_nothrow_default_constructible<container_type>::value)
+        : c() {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    queue(const queue& __q) : c(__q.c) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    queue& operator=(const queue& __q) {c = __q.c; return *this;}
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    queue(queue&& __q)
+        _NOEXCEPT_(is_nothrow_move_constructible<container_type>::value)
+        : c(_VSTD::move(__q.c)) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    queue& operator=(queue&& __q)
+        _NOEXCEPT_(is_nothrow_move_assignable<container_type>::value)
+        {c = _VSTD::move(__q.c); return *this;}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit queue(const container_type& __c)  : c(__c) {}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    explicit queue(container_type&& __c) : c(_VSTD::move(__c)) {}
+#endif // _LIBCPP_CXX03_LANG
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        explicit queue(const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0)
+            : c(__a) {}
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        queue(const queue& __q, const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0)
+            : c(__q.c, __a) {}
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        queue(const container_type& __c, const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0)
+            : c(__c, __a) {}
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        queue(container_type&& __c, const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0)
+            : c(_VSTD::move(__c), __a) {}
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        queue(queue&& __q, const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0)
+            : c(_VSTD::move(__q.c), __a) {}
+
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool      empty() const {return c.empty();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const  {return c.size();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference       front()       {return c.front();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference front() const {return c.front();}
+    _LIBCPP_INLINE_VISIBILITY
+    reference       back()        {return c.back();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference back() const  {return c.back();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void push(const value_type& __v) {c.push_back(__v);}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void push(value_type&& __v)      {c.push_back(_VSTD::move(__v));}
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+#if _LIBCPP_STD_VER > 14
+        decltype(auto) emplace(_Args&&... __args)
+            { return c.emplace_back(_VSTD::forward<_Args>(__args)...);}
+#else
+        void     emplace(_Args&&... __args)
+            {        c.emplace_back(_VSTD::forward<_Args>(__args)...);}
+#endif
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void pop() {c.pop_front();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(queue& __q)
+        _NOEXCEPT_(__is_nothrow_swappable<container_type>::value)
+    {
+        using _VSTD::swap;
+        swap(c, __q.c);
+    }
+
+    template <class _T1, class _C1>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    bool
+    operator==(const queue<_T1, _C1>& __x,const queue<_T1, _C1>& __y);
+
+    template <class _T1, class _C1>
+    friend
+    _LIBCPP_INLINE_VISIBILITY
+    bool
+    operator< (const queue<_T1, _C1>& __x,const queue<_T1, _C1>& __y);
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _Container,
+         class = enable_if_t<!__is_allocator<_Container>::value>
+>
+queue(_Container)
+    -> queue<typename _Container::value_type, _Container>;
+
+template<class _Container,
+         class _Alloc,
+         class = enable_if_t<!__is_allocator<_Container>::value>,
+         class = enable_if_t<uses_allocator<_Container, _Alloc>::value>
+>
+queue(_Container, _Alloc)
+    -> queue<typename _Container::value_type, _Container>;
+#endif
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const queue<_Tp, _Container>& __x,const queue<_Tp, _Container>& __y)
+{
+    return __x.c == __y.c;
+}
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const queue<_Tp, _Container>& __x,const queue<_Tp, _Container>& __y)
+{
+    return __x.c < __y.c;
+}
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const queue<_Tp, _Container>& __x,const queue<_Tp, _Container>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const queue<_Tp, _Container>& __x,const queue<_Tp, _Container>& __y)
+{
+    return __y < __x;
+}
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const queue<_Tp, _Container>& __x,const queue<_Tp, _Container>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const queue<_Tp, _Container>& __x,const queue<_Tp, _Container>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+__enable_if_t<__is_swappable<_Container>::value, void>
+swap(queue<_Tp, _Container>& __x, queue<_Tp, _Container>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+template <class _Tp, class _Container, class _Alloc>
+struct _LIBCPP_TEMPLATE_VIS uses_allocator<queue<_Tp, _Container>, _Alloc>
+    : public uses_allocator<_Container, _Alloc>
+{
+};
+
+template <class _Tp, class _Container = vector<_Tp>,
+          class _Compare = less<typename _Container::value_type> >
+class _LIBCPP_TEMPLATE_VIS priority_queue
+{
+public:
+    typedef _Container                               container_type;
+    typedef _Compare                                 value_compare;
+    typedef typename container_type::value_type      value_type;
+    typedef typename container_type::reference       reference;
+    typedef typename container_type::const_reference const_reference;
+    typedef typename container_type::size_type       size_type;
+    static_assert((is_same<_Tp, value_type>::value), "" );
+
+protected:
+    container_type c;
+    value_compare comp;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    priority_queue()
+        _NOEXCEPT_(is_nothrow_default_constructible<container_type>::value &&
+                   is_nothrow_default_constructible<value_compare>::value)
+        : c(), comp() {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    priority_queue(const priority_queue& __q) : c(__q.c), comp(__q.comp) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    priority_queue& operator=(const priority_queue& __q)
+        {c = __q.c; comp = __q.comp; return *this;}
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    priority_queue(priority_queue&& __q)
+        _NOEXCEPT_(is_nothrow_move_constructible<container_type>::value &&
+                   is_nothrow_move_constructible<value_compare>::value)
+        : c(_VSTD::move(__q.c)), comp(_VSTD::move(__q.comp)) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    priority_queue& operator=(priority_queue&& __q)
+        _NOEXCEPT_(is_nothrow_move_assignable<container_type>::value &&
+                   is_nothrow_move_assignable<value_compare>::value)
+        {c = _VSTD::move(__q.c); comp = _VSTD::move(__q.comp); return *this;}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit priority_queue(const value_compare& __comp)
+        : c(), comp(__comp) {}
+    _LIBCPP_INLINE_VISIBILITY
+    priority_queue(const value_compare& __comp, const container_type& __c);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    priority_queue(const value_compare& __comp, container_type&& __c);
+#endif
+    template <class _InputIter, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+        _LIBCPP_INLINE_VISIBILITY
+        priority_queue(_InputIter __f, _InputIter __l,
+                       const value_compare& __comp = value_compare());
+    template <class _InputIter, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+        _LIBCPP_INLINE_VISIBILITY
+        priority_queue(_InputIter __f, _InputIter __l,
+                       const value_compare& __comp, const container_type& __c);
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _InputIter, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+        _LIBCPP_INLINE_VISIBILITY
+        priority_queue(_InputIter __f, _InputIter __l,
+                       const value_compare& __comp, container_type&& __c);
+#endif // _LIBCPP_CXX03_LANG
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        explicit priority_queue(const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        priority_queue(const value_compare& __comp, const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        priority_queue(const value_compare& __comp, const container_type& __c,
+                       const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        priority_queue(const priority_queue& __q, const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        priority_queue(const value_compare& __comp, container_type&& __c,
+                       const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        priority_queue(priority_queue&& __q, const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
+#endif // _LIBCPP_CXX03_LANG
+
+    template <class _InputIter, class _Alloc, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+        _LIBCPP_INLINE_VISIBILITY
+        priority_queue(_InputIter __f, _InputIter __l, const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
+
+    template <class _InputIter, class _Alloc, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+        _LIBCPP_INLINE_VISIBILITY
+        priority_queue(_InputIter __f, _InputIter __l,
+                       const value_compare& __comp, const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
+
+    template <class _InputIter, class _Alloc, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+        _LIBCPP_INLINE_VISIBILITY
+        priority_queue(_InputIter __f, _InputIter __l,
+                       const value_compare& __comp, const container_type& __c, const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _InputIter, class _Alloc, class = __enable_if_t<__is_cpp17_input_iterator<_InputIter>::value> >
+        _LIBCPP_INLINE_VISIBILITY
+        priority_queue(_InputIter __f, _InputIter __l,
+                       const value_compare& __comp, container_type&& __c, const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0);
+#endif  // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool            empty() const {return c.empty();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type       size() const  {return c.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference top() const   {return c.front();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void push(const value_type& __v);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void push(value_type&& __v);
+    template <class... _Args>
+    _LIBCPP_INLINE_VISIBILITY
+    void emplace(_Args&&... __args);
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void pop();
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(priority_queue& __q)
+        _NOEXCEPT_(__is_nothrow_swappable<container_type>::value &&
+                   __is_nothrow_swappable<value_compare>::value);
+};
+
+#if _LIBCPP_STD_VER >= 17
+template <class _Compare,
+          class _Container,
+          class = enable_if_t<!__is_allocator<_Compare>::value>,
+          class = enable_if_t<!__is_allocator<_Container>::value>
+>
+priority_queue(_Compare, _Container)
+    -> priority_queue<typename _Container::value_type, _Container, _Compare>;
+
+template<class _InputIterator,
+         class _Compare = less<__iter_value_type<_InputIterator>>,
+         class _Container = vector<__iter_value_type<_InputIterator>>,
+         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<!__is_allocator<_Compare>::value>,
+         class = enable_if_t<!__is_allocator<_Container>::value>
+>
+priority_queue(_InputIterator, _InputIterator, _Compare = _Compare(), _Container = _Container())
+    -> priority_queue<__iter_value_type<_InputIterator>, _Container, _Compare>;
+
+template<class _Compare,
+         class _Container,
+         class _Alloc,
+         class = enable_if_t<!__is_allocator<_Compare>::value>,
+         class = enable_if_t<!__is_allocator<_Container>::value>,
+         class = enable_if_t<uses_allocator<_Container, _Alloc>::value>
+>
+priority_queue(_Compare, _Container, _Alloc)
+    -> priority_queue<typename _Container::value_type, _Container, _Compare>;
+
+template<class _InputIterator, class _Allocator,
+         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>
+>
+priority_queue(_InputIterator, _InputIterator, _Allocator)
+    -> priority_queue<__iter_value_type<_InputIterator>,
+                      vector<__iter_value_type<_InputIterator>, _Allocator>,
+                      less<__iter_value_type<_InputIterator>>>;
+
+template<class _InputIterator, class _Compare, class _Allocator,
+         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<!__is_allocator<_Compare>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>
+>
+priority_queue(_InputIterator, _InputIterator, _Compare, _Allocator)
+    -> priority_queue<__iter_value_type<_InputIterator>,
+                      vector<__iter_value_type<_InputIterator>, _Allocator>, _Compare>;
+
+template<class _InputIterator, class _Compare, class _Container, class _Alloc,
+         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<!__is_allocator<_Compare>::value>,
+         class = enable_if_t<!__is_allocator<_Container>::value>,
+         class = enable_if_t<uses_allocator<_Container, _Alloc>::value>
+>
+priority_queue(_InputIterator, _InputIterator, _Compare, _Container, _Alloc)
+    -> priority_queue<typename _Container::value_type, _Container, _Compare>;
+#endif
+
+template <class _Tp, class _Container, class _Compare>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(const _Compare& __comp,
+                                                          const container_type& __c)
+    : c(__c),
+      comp(__comp)
+{
+    _VSTD::make_heap(c.begin(), c.end(), comp);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Container, class _Compare>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(const value_compare& __comp,
+                                                          container_type&& __c)
+    : c(_VSTD::move(__c)),
+      comp(__comp)
+{
+    _VSTD::make_heap(c.begin(), c.end(), comp);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Container, class _Compare>
+template <class _InputIter, class>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(_InputIter __f, _InputIter __l,
+                                                          const value_compare& __comp)
+    : c(__f, __l),
+      comp(__comp)
+{
+    _VSTD::make_heap(c.begin(), c.end(), comp);
+}
+
+template <class _Tp, class _Container, class _Compare>
+template <class _InputIter, class>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(_InputIter __f, _InputIter __l,
+                                                          const value_compare& __comp,
+                                                          const container_type& __c)
+    : c(__c),
+      comp(__comp)
+{
+    c.insert(c.end(), __f, __l);
+    _VSTD::make_heap(c.begin(), c.end(), comp);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Container, class _Compare>
+template <class _InputIter, class>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(_InputIter __f, _InputIter __l,
+                                                          const value_compare& __comp,
+                                                          container_type&& __c)
+    : c(_VSTD::move(__c)),
+      comp(__comp)
+{
+    c.insert(c.end(), __f, __l);
+    _VSTD::make_heap(c.begin(), c.end(), comp);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Container, class _Compare>
+template <class _Alloc>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>*)
+    : c(__a)
+{
+}
+
+template <class _Tp, class _Container, class _Compare>
+template <class _Alloc>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(const value_compare& __comp,
+                                                          const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>*)
+    : c(__a),
+      comp(__comp)
+{
+}
+
+template <class _Tp, class _Container, class _Compare>
+template <class _Alloc>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(const value_compare& __comp,
+                                                          const container_type& __c,
+                                                          const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>*)
+    : c(__c, __a),
+      comp(__comp)
+{
+    _VSTD::make_heap(c.begin(), c.end(), comp);
+}
+
+template <class _Tp, class _Container, class _Compare>
+template <class _Alloc>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(const priority_queue& __q,
+                                                          const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>*)
+    : c(__q.c, __a),
+      comp(__q.comp)
+{
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Container, class _Compare>
+template <class _Alloc>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(const value_compare& __comp,
+                                                          container_type&& __c,
+                                                          const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>*)
+    : c(_VSTD::move(__c), __a),
+      comp(__comp)
+{
+    _VSTD::make_heap(c.begin(), c.end(), comp);
+}
+
+template <class _Tp, class _Container, class _Compare>
+template <class _Alloc>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(priority_queue&& __q,
+                                                          const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>*)
+    : c(_VSTD::move(__q.c), __a),
+      comp(_VSTD::move(__q.comp))
+{
+}
+
+#endif  // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Container, class _Compare>
+template <class _InputIter, class _Alloc, class>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(
+        _InputIter __f, _InputIter __l, const _Alloc& __a,
+        __enable_if_t<uses_allocator<container_type, _Alloc>::value>*)
+    : c(__f, __l, __a),
+      comp()
+{
+    _VSTD::make_heap(c.begin(), c.end(), comp);
+}
+
+template <class _Tp, class _Container, class _Compare>
+template <class _InputIter, class _Alloc, class>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(
+        _InputIter __f, _InputIter __l,
+        const value_compare& __comp, const _Alloc& __a,
+        __enable_if_t<uses_allocator<container_type, _Alloc>::value>*)
+    : c(__f, __l, __a),
+      comp(__comp)
+{
+    _VSTD::make_heap(c.begin(), c.end(), comp);
+}
+
+template <class _Tp, class _Container, class _Compare>
+template <class _InputIter, class _Alloc, class>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(
+        _InputIter __f, _InputIter __l,
+        const value_compare& __comp, const container_type& __c, const _Alloc& __a,
+        __enable_if_t<uses_allocator<container_type, _Alloc>::value>*)
+    : c(__c, __a),
+      comp(__comp)
+{
+    c.insert(c.end(), __f, __l);
+    _VSTD::make_heap(c.begin(), c.end(), comp);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp, class _Container, class _Compare>
+template <class _InputIter, class _Alloc, class>
+inline
+priority_queue<_Tp, _Container, _Compare>::priority_queue(
+        _InputIter __f, _InputIter __l, const value_compare& __comp,
+        container_type&& __c, const _Alloc& __a,
+        __enable_if_t<uses_allocator<container_type, _Alloc>::value>*)
+    : c(_VSTD::move(__c), __a),
+      comp(__comp)
+{
+    c.insert(c.end(), __f, __l);
+    _VSTD::make_heap(c.begin(), c.end(), comp);
+}
+#endif  // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Container, class _Compare>
+inline
+void
+priority_queue<_Tp, _Container, _Compare>::push(const value_type& __v)
+{
+    c.push_back(__v);
+    _VSTD::push_heap(c.begin(), c.end(), comp);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Container, class _Compare>
+inline
+void
+priority_queue<_Tp, _Container, _Compare>::push(value_type&& __v)
+{
+    c.push_back(_VSTD::move(__v));
+    _VSTD::push_heap(c.begin(), c.end(), comp);
+}
+
+template <class _Tp, class _Container, class _Compare>
+template <class... _Args>
+inline
+void
+priority_queue<_Tp, _Container, _Compare>::emplace(_Args&&... __args)
+{
+    c.emplace_back(_VSTD::forward<_Args>(__args)...);
+    _VSTD::push_heap(c.begin(), c.end(), comp);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Container, class _Compare>
+inline
+void
+priority_queue<_Tp, _Container, _Compare>::pop()
+{
+    _VSTD::pop_heap(c.begin(), c.end(), comp);
+    c.pop_back();
+}
+
+template <class _Tp, class _Container, class _Compare>
+inline
+void
+priority_queue<_Tp, _Container, _Compare>::swap(priority_queue& __q)
+        _NOEXCEPT_(__is_nothrow_swappable<container_type>::value &&
+                   __is_nothrow_swappable<value_compare>::value)
+{
+    using _VSTD::swap;
+    swap(c, __q.c);
+    swap(comp, __q.comp);
+}
+
+template <class _Tp, class _Container, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY
+__enable_if_t<
+    __is_swappable<_Container>::value && __is_swappable<_Compare>::value,
+    void
+>
+swap(priority_queue<_Tp, _Container, _Compare>& __x,
+     priority_queue<_Tp, _Container, _Compare>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+template <class _Tp, class _Container, class _Compare, class _Alloc>
+struct _LIBCPP_TEMPLATE_VIS uses_allocator<priority_queue<_Tp, _Container, _Compare>, _Alloc>
+    : public uses_allocator<_Container, _Alloc>
+{
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_QUEUE
diff --git a/contrib/libs/cxxsupp/libcxx/include/random b/contrib/libs/cxxsupp/libcxx/include/random
new file mode 100644
index 00000000000..13202508970
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/random
@@ -0,0 +1,7022 @@
+// -*- C++ -*-
+//===--------------------------- random -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_RANDOM
+#define _LIBCPP_RANDOM
+
+/*
+    random synopsis
+
+#include <initializer_list>
+
+namespace std
+{
+// [rand.req.urng], uniform random bit generator requirements
+template<class G>
+concept uniform_random_bit_generator = see below; // C++20
+
+// Engines
+
+template <class UIntType, UIntType a, UIntType c, UIntType m>
+class linear_congruential_engine
+{
+public:
+    // types
+    typedef UIntType result_type;
+
+    // engine characteristics
+    static constexpr result_type multiplier = a;
+    static constexpr result_type increment = c;
+    static constexpr result_type modulus = m;
+    static constexpr result_type min() { return c == 0u ? 1u: 0u;}
+    static constexpr result_type max() { return m - 1u;}
+    static constexpr result_type default_seed = 1u;
+
+    // constructors and seeding functions
+    explicit linear_congruential_engine(result_type s = default_seed);         // before C++20
+    linear_congruential_engine() : linear_congruential_engine(default_seed) {} // C++20
+    explicit linear_congruential_engine(result_type s);                        // C++20
+    template<class Sseq> explicit linear_congruential_engine(Sseq& q);
+    void seed(result_type s = default_seed);
+    template<class Sseq> void seed(Sseq& q);
+
+    // generating functions
+    result_type operator()();
+    void discard(unsigned long long z);
+};
+
+template <class UIntType, UIntType a, UIntType c, UIntType m>
+bool
+operator==(const linear_congruential_engine<UIntType, a, c, m>& x,
+           const linear_congruential_engine<UIntType, a, c, m>& y);
+
+template <class UIntType, UIntType a, UIntType c, UIntType m>
+bool
+operator!=(const linear_congruential_engine<UIntType, a, c, m>& x,
+           const linear_congruential_engine<UIntType, a, c, m>& y);
+
+template <class charT, class traits,
+          class UIntType, UIntType a, UIntType c, UIntType m>
+basic_ostream<charT, traits>&
+operator<<(basic_ostream<charT, traits>& os,
+           const linear_congruential_engine<UIntType, a, c, m>& x);
+
+template <class charT, class traits,
+          class UIntType, UIntType a, UIntType c, UIntType m>
+basic_istream<charT, traits>&
+operator>>(basic_istream<charT, traits>& is,
+           linear_congruential_engine<UIntType, a, c, m>& x);
+
+template <class UIntType, size_t w, size_t n, size_t m, size_t r,
+          UIntType a, size_t u, UIntType d, size_t s,
+          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
+class mersenne_twister_engine
+{
+public:
+    // types
+    typedef UIntType result_type;
+
+    // engine characteristics
+    static constexpr size_t word_size = w;
+    static constexpr size_t state_size = n;
+    static constexpr size_t shift_size = m;
+    static constexpr size_t mask_bits = r;
+    static constexpr result_type xor_mask = a;
+    static constexpr size_t tempering_u = u;
+    static constexpr result_type tempering_d = d;
+    static constexpr size_t tempering_s = s;
+    static constexpr result_type tempering_b = b;
+    static constexpr size_t tempering_t = t;
+    static constexpr result_type tempering_c = c;
+    static constexpr size_t tempering_l = l;
+    static constexpr result_type initialization_multiplier = f;
+    static constexpr result_type min () { return 0; }
+    static constexpr result_type max() { return 2^w - 1; }
+    static constexpr result_type default_seed = 5489u;
+
+    // constructors and seeding functions
+    explicit mersenne_twister_engine(result_type s = default_seed);      // before C++20
+    mersenne_twister_engine() : mersenne_twister_engine(default_seed) {} // C++20
+    explicit mersenne_twister_engine(result_type s);                     // C++20
+    template<class Sseq> explicit mersenne_twister_engine(Sseq& q);
+    void seed(result_type value = default_seed);
+    template<class Sseq> void seed(Sseq& q);
+
+    // generating functions
+    result_type operator()();
+    void discard(unsigned long long z);
+};
+
+template <class UIntType, size_t w, size_t n, size_t m, size_t r,
+          UIntType a, size_t u, UIntType d, size_t s,
+          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
+bool
+operator==(
+    const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& x,
+    const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& y);
+
+template <class UIntType, size_t w, size_t n, size_t m, size_t r,
+          UIntType a, size_t u, UIntType d, size_t s,
+          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
+bool
+operator!=(
+    const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& x,
+    const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& y);
+
+template <class charT, class traits,
+          class UIntType, size_t w, size_t n, size_t m, size_t r,
+          UIntType a, size_t u, UIntType d, size_t s,
+          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
+basic_ostream<charT, traits>&
+operator<<(basic_ostream<charT, traits>& os,
+           const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& x);
+
+template <class charT, class traits,
+          class UIntType, size_t w, size_t n, size_t m, size_t r,
+          UIntType a, size_t u, UIntType d, size_t s,
+          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
+basic_istream<charT, traits>&
+operator>>(basic_istream<charT, traits>& is,
+           mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& x);
+
+template<class UIntType, size_t w, size_t s, size_t r>
+class subtract_with_carry_engine
+{
+public:
+    // types
+    typedef UIntType result_type;
+
+    // engine characteristics
+    static constexpr size_t word_size = w;
+    static constexpr size_t short_lag = s;
+    static constexpr size_t long_lag = r;
+    static constexpr result_type min() { return 0; }
+    static constexpr result_type max() { return m-1; }
+    static constexpr result_type default_seed = 19780503u;
+
+    // constructors and seeding functions
+    explicit subtract_with_carry_engine(result_type value = default_seed);     // before C++20
+    subtract_with_carry_engine() : subtract_with_carry_engine(default_seed) {} // C++20
+    explicit subtract_with_carry_engine(result_type value);                    // C++20
+    template<class Sseq> explicit subtract_with_carry_engine(Sseq& q);
+    void seed(result_type value = default_seed);
+    template<class Sseq> void seed(Sseq& q);
+
+    // generating functions
+    result_type operator()();
+    void discard(unsigned long long z);
+};
+
+template<class UIntType, size_t w, size_t s, size_t r>
+bool
+operator==(
+    const subtract_with_carry_engine<UIntType, w, s, r>& x,
+    const subtract_with_carry_engine<UIntType, w, s, r>& y);
+
+template<class UIntType, size_t w, size_t s, size_t r>
+bool
+operator!=(
+    const subtract_with_carry_engine<UIntType, w, s, r>& x,
+    const subtract_with_carry_engine<UIntType, w, s, r>& y);
+
+template <class charT, class traits,
+          class UIntType, size_t w, size_t s, size_t r>
+basic_ostream<charT, traits>&
+operator<<(basic_ostream<charT, traits>& os,
+           const subtract_with_carry_engine<UIntType, w, s, r>& x);
+
+template <class charT, class traits,
+          class UIntType, size_t w, size_t s, size_t r>
+basic_istream<charT, traits>&
+operator>>(basic_istream<charT, traits>& is,
+           subtract_with_carry_engine<UIntType, w, s, r>& x);
+
+template<class Engine, size_t p, size_t r>
+class discard_block_engine
+{
+public:
+    // types
+    typedef typename Engine::result_type result_type;
+
+    // engine characteristics
+    static constexpr size_t block_size = p;
+    static constexpr size_t used_block = r;
+    static constexpr result_type min() { return Engine::min(); }
+    static constexpr result_type max() { return Engine::max(); }
+
+    // constructors and seeding functions
+    discard_block_engine();
+    explicit discard_block_engine(const Engine& e);
+    explicit discard_block_engine(Engine&& e);
+    explicit discard_block_engine(result_type s);
+    template<class Sseq> explicit discard_block_engine(Sseq& q);
+    void seed();
+    void seed(result_type s);
+    template<class Sseq> void seed(Sseq& q);
+
+    // generating functions
+    result_type operator()();
+    void discard(unsigned long long z);
+
+    // property functions
+    const Engine& base() const noexcept;
+};
+
+template<class Engine, size_t p, size_t r>
+bool
+operator==(
+    const discard_block_engine<Engine, p, r>& x,
+    const discard_block_engine<Engine, p, r>& y);
+
+template<class Engine, size_t p, size_t r>
+bool
+operator!=(
+    const discard_block_engine<Engine, p, r>& x,
+    const discard_block_engine<Engine, p, r>& y);
+
+template <class charT, class traits,
+          class Engine, size_t p, size_t r>
+basic_ostream<charT, traits>&
+operator<<(basic_ostream<charT, traits>& os,
+           const discard_block_engine<Engine, p, r>& x);
+
+template <class charT, class traits,
+          class Engine, size_t p, size_t r>
+basic_istream<charT, traits>&
+operator>>(basic_istream<charT, traits>& is,
+           discard_block_engine<Engine, p, r>& x);
+
+template<class Engine, size_t w, class UIntType>
+class independent_bits_engine
+{
+public:
+    // types
+    typedef UIntType result_type;
+
+    // engine characteristics
+    static constexpr result_type min() { return 0; }
+    static constexpr result_type max() { return 2^w - 1; }
+
+    // constructors and seeding functions
+    independent_bits_engine();
+    explicit independent_bits_engine(const Engine& e);
+    explicit independent_bits_engine(Engine&& e);
+    explicit independent_bits_engine(result_type s);
+    template<class Sseq> explicit independent_bits_engine(Sseq& q);
+    void seed();
+    void seed(result_type s);
+    template<class Sseq> void seed(Sseq& q);
+
+    // generating functions
+    result_type operator()(); void discard(unsigned long long z);
+
+    // property functions
+    const Engine& base() const noexcept;
+};
+
+template<class Engine, size_t w, class UIntType>
+bool
+operator==(
+    const independent_bits_engine<Engine, w, UIntType>& x,
+    const independent_bits_engine<Engine, w, UIntType>& y);
+
+template<class Engine, size_t w, class UIntType>
+bool
+operator!=(
+    const independent_bits_engine<Engine, w, UIntType>& x,
+    const independent_bits_engine<Engine, w, UIntType>& y);
+
+template <class charT, class traits,
+          class Engine, size_t w, class UIntType>
+basic_ostream<charT, traits>&
+operator<<(basic_ostream<charT, traits>& os,
+           const independent_bits_engine<Engine, w, UIntType>& x);
+
+template <class charT, class traits,
+          class Engine, size_t w, class UIntType>
+basic_istream<charT, traits>&
+operator>>(basic_istream<charT, traits>& is,
+           independent_bits_engine<Engine, w, UIntType>& x);
+
+template<class Engine, size_t k>
+class shuffle_order_engine
+{
+public:
+    // types
+    typedef typename Engine::result_type result_type;
+
+    // engine characteristics
+    static constexpr size_t table_size = k;
+    static constexpr result_type min() { return Engine::min; }
+    static constexpr result_type max() { return Engine::max; }
+
+    // constructors and seeding functions
+    shuffle_order_engine();
+    explicit shuffle_order_engine(const Engine& e);
+    explicit shuffle_order_engine(Engine&& e);
+    explicit shuffle_order_engine(result_type s);
+    template<class Sseq> explicit shuffle_order_engine(Sseq& q);
+    void seed();
+    void seed(result_type s);
+    template<class Sseq> void seed(Sseq& q);
+
+    // generating functions
+    result_type operator()();
+    void discard(unsigned long long z);
+
+    // property functions
+    const Engine& base() const noexcept;
+};
+
+template<class Engine, size_t k>
+bool
+operator==(
+    const shuffle_order_engine<Engine, k>& x,
+    const shuffle_order_engine<Engine, k>& y);
+
+template<class Engine, size_t k>
+bool
+operator!=(
+    const shuffle_order_engine<Engine, k>& x,
+    const shuffle_order_engine<Engine, k>& y);
+
+template <class charT, class traits,
+          class Engine, size_t k>
+basic_ostream<charT, traits>&
+operator<<(basic_ostream<charT, traits>& os,
+           const shuffle_order_engine<Engine, k>& x);
+
+template <class charT, class traits,
+          class Engine, size_t k>
+basic_istream<charT, traits>&
+operator>>(basic_istream<charT, traits>& is,
+           shuffle_order_engine<Engine, k>& x);
+
+typedef linear_congruential_engine<uint_fast32_t, 16807, 0, 2147483647>
+                                                                   minstd_rand0;
+typedef linear_congruential_engine<uint_fast32_t, 48271, 0, 2147483647>
+                                                                    minstd_rand;
+typedef mersenne_twister_engine<uint_fast32_t, 32, 624, 397, 31,
+                                0x9908b0df,
+                                11, 0xffffffff,
+                                7,  0x9d2c5680,
+                                15, 0xefc60000,
+                                18, 1812433253>                         mt19937;
+typedef mersenne_twister_engine<uint_fast64_t, 64, 312, 156, 31,
+                                0xb5026f5aa96619e9,
+                                29, 0x5555555555555555,
+                                17, 0x71d67fffeda60000,
+                                37, 0xfff7eee000000000,
+                                43, 6364136223846793005>             mt19937_64;
+typedef subtract_with_carry_engine<uint_fast32_t, 24, 10, 24>     ranlux24_base;
+typedef subtract_with_carry_engine<uint_fast64_t, 48,  5, 12>     ranlux48_base;
+typedef discard_block_engine<ranlux24_base, 223, 23>                   ranlux24;
+typedef discard_block_engine<ranlux48_base, 389, 11>                   ranlux48;
+typedef shuffle_order_engine<minstd_rand0, 256>                         knuth_b;
+typedef minstd_rand                                       default_random_engine;
+
+// Generators
+
+class random_device
+{
+public:
+    // types
+    typedef unsigned int result_type;
+
+    // generator characteristics
+    static constexpr result_type min() { return numeric_limits<result_type>::min(); }
+    static constexpr result_type max() { return numeric_limits<result_type>::max(); }
+
+    // constructors
+    explicit random_device(const string& token = implementation-defined); // before C++20
+    random_device() : random_device(implementation-defined) {}            // C++20
+    explicit random_device(const string& token);                          // C++20
+
+    // generating functions
+    result_type operator()();
+
+    // property functions
+    double entropy() const noexcept;
+
+    // no copy functions
+    random_device(const random_device& ) = delete;
+    void operator=(const random_device& ) = delete;
+};
+
+// Utilities
+
+class seed_seq
+{
+public:
+    // types
+    typedef uint_least32_t result_type;
+
+    // constructors
+    seed_seq();
+    template<class T>
+        seed_seq(initializer_list<T> il);
+    template<class InputIterator>
+        seed_seq(InputIterator begin, InputIterator end);
+
+    // generating functions
+    template<class RandomAccessIterator>
+        void generate(RandomAccessIterator begin, RandomAccessIterator end);
+
+    // property functions
+    size_t size() const;
+    template<class OutputIterator>
+        void param(OutputIterator dest) const;
+
+    // no copy functions
+    seed_seq(const seed_seq&) = delete;
+    void operator=(const seed_seq& ) = delete;
+};
+
+template<class RealType, size_t bits, class URNG>
+    RealType generate_canonical(URNG& g);
+
+// Distributions
+
+template<class IntType = int>
+class uniform_int_distribution
+{
+public:
+    // types
+    typedef IntType result_type;
+
+    class param_type
+    {
+    public:
+        typedef uniform_int_distribution distribution_type;
+
+        explicit param_type(IntType a = 0,
+                                    IntType b = numeric_limits<IntType>::max());
+
+        result_type a() const;
+        result_type b() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructors and reset functions
+    explicit uniform_int_distribution(IntType a = 0,
+                                      IntType b = numeric_limits<IntType>::max()); // before C++20
+    uniform_int_distribution() : uniform_int_distribution(0) {}                    // C++20
+    explicit uniform_int_distribution(IntType a,
+                                      IntType b = numeric_limits<IntType>::max()); // C++20
+    explicit uniform_int_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    result_type a() const;
+    result_type b() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const uniform_int_distribution& x,
+                           const uniform_int_distribution& y);
+    friend bool operator!=(const uniform_int_distribution& x,
+                           const uniform_int_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const uniform_int_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               uniform_int_distribution& x);
+};
+
+template<class RealType = double>
+class uniform_real_distribution
+{
+public:
+    // types
+    typedef RealType result_type;
+
+    class param_type
+    {
+    public:
+        typedef uniform_real_distribution distribution_type;
+
+        explicit param_type(RealType a = 0,
+                            RealType b = 1);
+
+        result_type a() const;
+        result_type b() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructors and reset functions
+    explicit uniform_real_distribution(RealType a = 0.0, RealType b = 1.0); // before C++20
+    uniform_real_distribution() : uniform_real_distribution(0.0) {}         // C++20
+    explicit uniform_real_distribution(RealType a, RealType b = 1.0);       // C++20
+    explicit uniform_real_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    result_type a() const;
+    result_type b() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const uniform_real_distribution& x,
+                           const uniform_real_distribution& y);
+    friend bool operator!=(const uniform_real_distribution& x,
+                           const uniform_real_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const uniform_real_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               uniform_real_distribution& x);
+};
+
+class bernoulli_distribution
+{
+public:
+    // types
+    typedef bool result_type;
+
+    class param_type
+    {
+    public:
+        typedef bernoulli_distribution distribution_type;
+
+        explicit param_type(double p = 0.5);
+
+        double p() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructors and reset functions
+    explicit bernoulli_distribution(double p = 0.5);          // before C++20
+    bernoulli_distribution() : bernoulli_distribution(0.5) {} // C++20
+    explicit bernoulli_distribution(double p);                // C++20
+    explicit bernoulli_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    double p() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const bernoulli_distribution& x,
+                           const bernoulli_distribution& y);
+    friend bool operator!=(const bernoulli_distribution& x,
+                           const bernoulli_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const bernoulli_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               bernoulli_distribution& x);
+};
+
+template<class IntType = int>
+class binomial_distribution
+{
+public:
+    // types
+    typedef IntType result_type;
+
+    class param_type
+    {
+    public:
+        typedef binomial_distribution distribution_type;
+
+        explicit param_type(IntType t = 1, double p = 0.5);
+
+        IntType t() const;
+        double p() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructors and reset functions
+    explicit binomial_distribution(IntType t = 1, double p = 0.5); // before C++20
+    binomial_distribution() : binomial_distribution(1) {}          // C++20
+    explicit binomial_distribution(IntType t, double p = 0.5);     // C++20
+    explicit binomial_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    IntType t() const;
+    double p() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const binomial_distribution& x,
+                           const binomial_distribution& y);
+    friend bool operator!=(const binomial_distribution& x,
+                           const binomial_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const binomial_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               binomial_distribution& x);
+};
+
+template<class IntType = int>
+class geometric_distribution
+{
+public:
+    // types
+    typedef IntType result_type;
+
+    class param_type
+    {
+    public:
+        typedef geometric_distribution distribution_type;
+
+        explicit param_type(double p = 0.5);
+
+        double p() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructors and reset functions
+    explicit geometric_distribution(double p = 0.5);          // before C++20
+    geometric_distribution() : geometric_distribution(0.5) {} // C++20
+    explicit geometric_distribution(double p);                // C++20
+    explicit geometric_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    double p() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const geometric_distribution& x,
+                           const geometric_distribution& y);
+    friend bool operator!=(const geometric_distribution& x,
+                           const geometric_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const geometric_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               geometric_distribution& x);
+};
+
+template<class IntType = int>
+class negative_binomial_distribution
+{
+public:
+    // types
+    typedef IntType result_type;
+
+    class param_type
+    {
+    public:
+        typedef negative_binomial_distribution distribution_type;
+
+        explicit param_type(result_type k = 1, double p = 0.5);
+
+        result_type k() const;
+        double p() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructor and reset functions
+    explicit negative_binomial_distribution(IntType k = 1, double p = 0.5); // before C++20
+    negative_binomial_distribution() : negative_binomial_distribution(1) {} // C++20
+    explicit negative_binomial_distribution(IntType k, double p = 0.5);     // C++20
+    explicit negative_binomial_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    result_type k() const;
+    double p() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const negative_binomial_distribution& x,
+                           const negative_binomial_distribution& y);
+    friend bool operator!=(const negative_binomial_distribution& x,
+                           const negative_binomial_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const negative_binomial_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               negative_binomial_distribution& x);
+};
+
+template<class IntType = int>
+class poisson_distribution
+{
+public:
+    // types
+    typedef IntType result_type;
+
+    class param_type
+    {
+    public:
+        typedef poisson_distribution distribution_type;
+
+        explicit param_type(double mean = 1.0);
+
+        double mean() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructors and reset functions
+    explicit poisson_distribution(double mean = 1.0);     // before C++20
+    poisson_distribution() : poisson_distribution(1.0) {} // C++20
+    explicit poisson_distribution(double mean);           // C++20
+    explicit poisson_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    double mean() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const poisson_distribution& x,
+                           const poisson_distribution& y);
+    friend bool operator!=(const poisson_distribution& x,
+                           const poisson_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const poisson_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               poisson_distribution& x);
+};
+
+template<class RealType = double>
+class exponential_distribution
+{
+public:
+    // types
+    typedef RealType result_type;
+
+    class param_type
+    {
+    public:
+        typedef exponential_distribution distribution_type;
+
+        explicit param_type(result_type lambda = 1.0);
+
+        result_type lambda() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructors and reset functions
+    explicit exponential_distribution(RealType lambda = 1.0);     // before C++20
+    exponential_distribution() : exponential_distribution(1.0) {} // C++20
+    explicit exponential_distribution(RealType lambda);           // C++20
+    explicit exponential_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    result_type lambda() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const exponential_distribution& x,
+                           const exponential_distribution& y);
+    friend bool operator!=(const exponential_distribution& x,
+                           const exponential_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const exponential_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               exponential_distribution& x);
+};
+
+template<class RealType = double>
+class gamma_distribution
+{
+public:
+    // types
+    typedef RealType result_type;
+
+    class param_type
+    {
+    public:
+        typedef gamma_distribution distribution_type;
+
+        explicit param_type(result_type alpha = 1, result_type beta = 1);
+
+        result_type alpha() const;
+        result_type beta() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructors and reset functions
+    explicit gamma_distribution(RealType alpha = 0.0, RealType beta = 1.0); // before C++20
+    gamma_distribution() : gamma_distribution(0.0) {}                       // C++20
+    explicit gamma_distribution(RealType alpha, RealType beta = 1.0);       // C++20
+    explicit gamma_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    result_type alpha() const;
+    result_type beta() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const gamma_distribution& x,
+                           const gamma_distribution& y);
+    friend bool operator!=(const gamma_distribution& x,
+                           const gamma_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const gamma_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               gamma_distribution& x);
+};
+
+template<class RealType = double>
+class weibull_distribution
+{
+public:
+    // types
+    typedef RealType result_type;
+
+    class param_type
+    {
+    public:
+        typedef weibull_distribution distribution_type;
+
+        explicit param_type(result_type alpha = 1, result_type beta = 1);
+
+        result_type a() const;
+        result_type b() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructor and reset functions
+    explicit weibull_distribution(RealType a = 1.0, RealType b = 1.0); // before C++20
+    weibull_distribution() : weibull_distribution(1.0) {}              // C++20
+    explicit weibull_distribution(RealType a, RealType b = 1.0);       // C++20
+    explicit weibull_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    result_type a() const;
+    result_type b() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const weibull_distribution& x,
+                           const weibull_distribution& y);
+    friend bool operator!=(const weibull_distribution& x,
+                           const weibull_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const weibull_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               weibull_distribution& x);
+};
+
+template<class RealType = double>
+class extreme_value_distribution
+{
+public:
+    // types
+    typedef RealType result_type;
+
+    class param_type
+    {
+    public:
+        typedef extreme_value_distribution distribution_type;
+
+        explicit param_type(result_type a = 0, result_type b = 1);
+
+        result_type a() const;
+        result_type b() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructor and reset functions
+    explicit extreme_value_distribution(RealType a = 0.0, RealType b = 1.0); // before C++20
+    extreme_value_distribution() : extreme_value_distribution(0.0) {}        // C++20
+    explicit extreme_value_distribution(RealType a, RealType b = 1.0);       // C++20
+    explicit extreme_value_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    result_type a() const;
+    result_type b() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const extreme_value_distribution& x,
+                           const extreme_value_distribution& y);
+    friend bool operator!=(const extreme_value_distribution& x,
+                           const extreme_value_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const extreme_value_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               extreme_value_distribution& x);
+};
+
+template<class RealType = double>
+class normal_distribution
+{
+public:
+    // types
+    typedef RealType result_type;
+
+    class param_type
+    {
+    public:
+        typedef normal_distribution distribution_type;
+
+        explicit param_type(result_type mean = 0, result_type stddev = 1);
+
+        result_type mean() const;
+        result_type stddev() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructors and reset functions
+    explicit normal_distribution(RealType mean = 0.0, RealType stddev = 1.0); // before C++20
+    normal_distribution() : normal_distribution(0.0) {}                       // C++20
+    explicit normal_distribution(RealType mean, RealType stddev = 1.0);       // C++20
+    explicit normal_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    result_type mean() const;
+    result_type stddev() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const normal_distribution& x,
+                           const normal_distribution& y);
+    friend bool operator!=(const normal_distribution& x,
+                           const normal_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const normal_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               normal_distribution& x);
+};
+
+template<class RealType = double>
+class lognormal_distribution
+{
+public:
+    // types
+    typedef RealType result_type;
+
+    class param_type
+    {
+    public:
+        typedef lognormal_distribution distribution_type;
+
+        explicit param_type(result_type m = 0, result_type s = 1);
+
+        result_type m() const;
+        result_type s() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructor and reset functions
+    explicit lognormal_distribution(RealType mean = 0.0, RealType stddev = 1.0); // before C++20
+    lognormal_distribution() : lognormal_distribution(0.0) {}                    // C++20
+    explicit lognormal_distribution(RealType mean, RealType stddev = 1.0);       // C++20
+    explicit lognormal_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    result_type m() const;
+    result_type s() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const lognormal_distribution& x,
+                           const lognormal_distribution& y);
+    friend bool operator!=(const lognormal_distribution& x,
+                           const lognormal_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const lognormal_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               lognormal_distribution& x);
+};
+
+template<class RealType = double>
+class chi_squared_distribution
+{
+public:
+    // types
+    typedef RealType result_type;
+
+    class param_type
+    {
+    public:
+        typedef chi_squared_distribution distribution_type;
+
+        explicit param_type(result_type n = 1);
+
+        result_type n() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructor and reset functions
+    explicit chi_squared_distribution(RealType n = 1.0);          // before C++20
+    chi_squared_distribution() : chi_squared_distribution(1.0) {} // C++20
+    explicit chi_squared_distribution(RealType n);                // C++20
+    explicit chi_squared_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    result_type n() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const chi_squared_distribution& x,
+                           const chi_squared_distribution& y);
+    friend bool operator!=(const chi_squared_distribution& x,
+                           const chi_squared_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const chi_squared_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               chi_squared_distribution& x);
+};
+
+template<class RealType = double>
+class cauchy_distribution
+{
+public:
+    // types
+    typedef RealType result_type;
+
+    class param_type
+    {
+    public:
+        typedef cauchy_distribution distribution_type;
+
+        explicit param_type(result_type a = 0, result_type b = 1);
+
+        result_type a() const;
+        result_type b() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructor and reset functions
+    explicit cauchy_distribution(RealType a = 0.0, RealType b = 1.0); // before C++20
+    cauchy_distribution() : cauchy_distribution(0.0) {}               // C++20
+    explicit cauchy_distribution(RealType a, RealType b = 1.0);       // C++20
+    explicit cauchy_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    result_type a() const;
+    result_type b() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const cauchy_distribution& x,
+                           const cauchy_distribution& y);
+    friend bool operator!=(const cauchy_distribution& x,
+                           const cauchy_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const cauchy_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               cauchy_distribution& x);
+};
+
+template<class RealType = double>
+class fisher_f_distribution
+{
+public:
+    // types
+    typedef RealType result_type;
+
+    class param_type
+    {
+    public:
+        typedef fisher_f_distribution distribution_type;
+
+        explicit param_type(result_type m = 1, result_type n = 1);
+
+        result_type m() const;
+        result_type n() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructor and reset functions
+    explicit fisher_f_distribution(RealType m = 1.0, RealType n = 1.0); // before C++20
+    fisher_f_distribution() : fisher_f_distribution(1.0) {}             // C++20
+    explicit fisher_f_distribution(RealType m, RealType n = 1.0);       // C++20
+    explicit fisher_f_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    result_type m() const;
+    result_type n() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const fisher_f_distribution& x,
+                           const fisher_f_distribution& y);
+    friend bool operator!=(const fisher_f_distribution& x,
+                           const fisher_f_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const fisher_f_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               fisher_f_distribution& x);
+};
+
+template<class RealType = double>
+class student_t_distribution
+{
+public:
+    // types
+    typedef RealType result_type;
+
+    class param_type
+    {
+    public:
+        typedef student_t_distribution distribution_type;
+
+        explicit param_type(result_type n = 1);
+
+        result_type n() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructor and reset functions
+    explicit student_t_distribution(RealType n = 1.0);        // before C++20
+    student_t_distribution() : student_t_distribution(1.0) {} // C++20
+    explicit student_t_distribution(RealType n);              // C++20
+    explicit student_t_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    result_type n() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const student_t_distribution& x,
+                           const student_t_distribution& y);
+    friend bool operator!=(const student_t_distribution& x,
+                           const student_t_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const student_t_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               student_t_distribution& x);
+};
+
+template<class IntType = int>
+class discrete_distribution
+{
+public:
+    // types
+    typedef IntType result_type;
+
+    class param_type
+    {
+    public:
+        typedef discrete_distribution distribution_type;
+
+        param_type();
+        template<class InputIterator>
+            param_type(InputIterator firstW, InputIterator lastW);
+        param_type(initializer_list<double> wl);
+        template<class UnaryOperation>
+            param_type(size_t nw, double xmin, double xmax, UnaryOperation fw);
+
+        vector<double> probabilities() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructor and reset functions
+    discrete_distribution();
+    template<class InputIterator>
+        discrete_distribution(InputIterator firstW, InputIterator lastW);
+    discrete_distribution(initializer_list<double> wl);
+    template<class UnaryOperation>
+        discrete_distribution(size_t nw, double xmin, double xmax,
+                              UnaryOperation fw);
+    explicit discrete_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    vector<double> probabilities() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const discrete_distribution& x,
+                           const discrete_distribution& y);
+    friend bool operator!=(const discrete_distribution& x,
+                           const discrete_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const discrete_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               discrete_distribution& x);
+};
+
+template<class RealType = double>
+class piecewise_constant_distribution
+{
+    // types
+    typedef RealType result_type;
+
+    class param_type
+    {
+    public:
+        typedef piecewise_constant_distribution distribution_type;
+
+        param_type();
+        template<class InputIteratorB, class InputIteratorW>
+            param_type(InputIteratorB firstB, InputIteratorB lastB,
+                       InputIteratorW firstW);
+        template<class UnaryOperation>
+            param_type(initializer_list<result_type> bl, UnaryOperation fw);
+        template<class UnaryOperation>
+            param_type(size_t nw, result_type xmin, result_type xmax,
+                       UnaryOperation fw);
+
+        vector<result_type> intervals() const;
+        vector<result_type> densities() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructor and reset functions
+    piecewise_constant_distribution();
+    template<class InputIteratorB, class InputIteratorW>
+        piecewise_constant_distribution(InputIteratorB firstB,
+                                        InputIteratorB lastB,
+                                        InputIteratorW firstW);
+    template<class UnaryOperation>
+        piecewise_constant_distribution(initializer_list<result_type> bl,
+                                        UnaryOperation fw);
+    template<class UnaryOperation>
+        piecewise_constant_distribution(size_t nw, result_type xmin,
+                                        result_type xmax, UnaryOperation fw);
+    explicit piecewise_constant_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    vector<result_type> intervals() const;
+    vector<result_type> densities() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const piecewise_constant_distribution& x,
+                           const piecewise_constant_distribution& y);
+    friend bool operator!=(const piecewise_constant_distribution& x,
+                           const piecewise_constant_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const piecewise_constant_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               piecewise_constant_distribution& x);
+};
+
+template<class RealType = double>
+class piecewise_linear_distribution
+{
+    // types
+    typedef RealType result_type;
+
+    class param_type
+    {
+    public:
+        typedef piecewise_linear_distribution distribution_type;
+
+        param_type();
+        template<class InputIteratorB, class InputIteratorW>
+            param_type(InputIteratorB firstB, InputIteratorB lastB,
+                       InputIteratorW firstW);
+        template<class UnaryOperation>
+            param_type(initializer_list<result_type> bl, UnaryOperation fw);
+        template<class UnaryOperation>
+            param_type(size_t nw, result_type xmin, result_type xmax,
+                       UnaryOperation fw);
+
+        vector<result_type> intervals() const;
+        vector<result_type> densities() const;
+
+        friend bool operator==(const param_type& x, const param_type& y);
+        friend bool operator!=(const param_type& x, const param_type& y);
+    };
+
+    // constructor and reset functions
+    piecewise_linear_distribution();
+    template<class InputIteratorB, class InputIteratorW>
+        piecewise_linear_distribution(InputIteratorB firstB,
+                                      InputIteratorB lastB,
+                                      InputIteratorW firstW);
+
+    template<class UnaryOperation>
+        piecewise_linear_distribution(initializer_list<result_type> bl,
+                                      UnaryOperation fw);
+
+    template<class UnaryOperation>
+        piecewise_linear_distribution(size_t nw, result_type xmin,
+                                      result_type xmax, UnaryOperation fw);
+
+    explicit piecewise_linear_distribution(const param_type& parm);
+    void reset();
+
+    // generating functions
+    template<class URNG> result_type operator()(URNG& g);
+    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
+
+    // property functions
+    vector<result_type> intervals() const;
+    vector<result_type> densities() const;
+
+    param_type param() const;
+    void param(const param_type& parm);
+
+    result_type min() const;
+    result_type max() const;
+
+    friend bool operator==(const piecewise_linear_distribution& x,
+                           const piecewise_linear_distribution& y);
+    friend bool operator!=(const piecewise_linear_distribution& x,
+                           const piecewise_linear_distribution& y);
+
+    template <class charT, class traits>
+    friend
+    basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os,
+               const piecewise_linear_distribution& x);
+
+    template <class charT, class traits>
+    friend
+    basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is,
+               piecewise_linear_distribution& x);
+};
+
+} // std
+*/
+
+#include <__config>
+#include <__random/uniform_int_distribution.h>
+#include <algorithm>
+#include <cmath>
+#include <concepts>
+#include <cstddef>
+#include <cstdint>
+#include <initializer_list>
+#include <iosfwd>
+#include <limits>
+#include <numeric>
+#include <string>
+#include <type_traits>
+#include <vector>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// [rand.req.urng]
+template<class _Gen>
+concept uniform_random_bit_generator =
+  invocable<_Gen&> && unsigned_integral<invoke_result_t<_Gen&>> &&
+  requires {
+    { _Gen::min() } -> same_as<invoke_result_t<_Gen&>>;
+    { _Gen::max() } -> same_as<invoke_result_t<_Gen&>>;
+    requires bool_constant<(_Gen::min() < _Gen::max())>::value;
+  };
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// __is_seed_sequence
+
+template <class _Sseq, class _Engine>
+struct __is_seed_sequence
+{
+    static _LIBCPP_CONSTEXPR const bool value =
+              !is_convertible<_Sseq, typename _Engine::result_type>::value &&
+              !is_same<typename remove_cv<_Sseq>::type, _Engine>::value;
+};
+
+// linear_congruential_engine
+
+template <unsigned long long __a, unsigned long long __c,
+          unsigned long long __m, unsigned long long _Mp,
+          bool _MightOverflow = (__a != 0 && __m != 0 && __m-1 > (_Mp-__c)/__a),
+          bool _OverflowOK = ((__m | (__m-1)) > __m), // m = 2^n
+          bool _SchrageOK = (__a != 0 && __m != 0 && __m % __a <= __m / __a)> // r <= q
+struct __lce_alg_picker
+{
+    static_assert(__a != 0 || __m != 0 || !_MightOverflow || _OverflowOK || _SchrageOK,
+                  "The current values of a, c, and m cannot generate a number "
+                  "within bounds of linear_congruential_engine.");
+
+    static _LIBCPP_CONSTEXPR const bool __use_schrage = _MightOverflow &&
+                                                        !_OverflowOK &&
+                                                        _SchrageOK;
+};
+
+template <unsigned long long __a, unsigned long long __c,
+          unsigned long long __m, unsigned long long _Mp,
+          bool _UseSchrage = __lce_alg_picker<__a, __c, __m, _Mp>::__use_schrage>
+struct __lce_ta;
+
+// 64
+
+template <unsigned long long __a, unsigned long long __c, unsigned long long __m>
+struct __lce_ta<__a, __c, __m, (unsigned long long)(~0), true>
+{
+    typedef unsigned long long result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    static result_type next(result_type __x)
+    {
+        // Schrage's algorithm
+        const result_type __q = __m / __a;
+        const result_type __r = __m % __a;
+        const result_type __t0 = __a * (__x % __q);
+        const result_type __t1 = __r * (__x / __q);
+        __x = __t0 + (__t0 < __t1) * __m - __t1;
+        __x += __c - (__x >= __m - __c) * __m;
+        return __x;
+    }
+};
+
+template <unsigned long long __a, unsigned long long __m>
+struct __lce_ta<__a, 0, __m, (unsigned long long)(~0), true>
+{
+    typedef unsigned long long result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    static result_type next(result_type __x)
+    {
+        // Schrage's algorithm
+        const result_type __q = __m / __a;
+        const result_type __r = __m % __a;
+        const result_type __t0 = __a * (__x % __q);
+        const result_type __t1 = __r * (__x / __q);
+        __x = __t0 + (__t0 < __t1) * __m - __t1;
+        return __x;
+    }
+};
+
+template <unsigned long long __a, unsigned long long __c, unsigned long long __m>
+struct __lce_ta<__a, __c, __m, (unsigned long long)(~0), false>
+{
+    typedef unsigned long long result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    static result_type next(result_type __x)
+    {
+        return (__a * __x + __c) % __m;
+    }
+};
+
+template <unsigned long long __a, unsigned long long __c>
+struct __lce_ta<__a, __c, 0, (unsigned long long)(~0), false>
+{
+    typedef unsigned long long result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    static result_type next(result_type __x)
+    {
+        return __a * __x + __c;
+    }
+};
+
+// 32
+
+template <unsigned long long _Ap, unsigned long long _Cp, unsigned long long _Mp>
+struct __lce_ta<_Ap, _Cp, _Mp, unsigned(~0), true>
+{
+    typedef unsigned result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    static result_type next(result_type __x)
+    {
+        const result_type __a = static_cast<result_type>(_Ap);
+        const result_type __c = static_cast<result_type>(_Cp);
+        const result_type __m = static_cast<result_type>(_Mp);
+        // Schrage's algorithm
+        const result_type __q = __m / __a;
+        const result_type __r = __m % __a;
+        const result_type __t0 = __a * (__x % __q);
+        const result_type __t1 = __r * (__x / __q);
+        __x = __t0 + (__t0 < __t1) * __m - __t1;
+        __x += __c - (__x >= __m - __c) * __m;
+        return __x;
+    }
+};
+
+template <unsigned long long _Ap, unsigned long long _Mp>
+struct __lce_ta<_Ap, 0, _Mp, unsigned(~0), true>
+{
+    typedef unsigned result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    static result_type next(result_type __x)
+    {
+        const result_type __a = static_cast<result_type>(_Ap);
+        const result_type __m = static_cast<result_type>(_Mp);
+        // Schrage's algorithm
+        const result_type __q = __m / __a;
+        const result_type __r = __m % __a;
+        const result_type __t0 = __a * (__x % __q);
+        const result_type __t1 = __r * (__x / __q);
+        __x = __t0 + (__t0 < __t1) * __m - __t1;
+        return __x;
+    }
+};
+
+template <unsigned long long _Ap, unsigned long long _Cp, unsigned long long _Mp>
+struct __lce_ta<_Ap, _Cp, _Mp, unsigned(~0), false>
+{
+    typedef unsigned result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    static result_type next(result_type __x)
+    {
+        const result_type __a = static_cast<result_type>(_Ap);
+        const result_type __c = static_cast<result_type>(_Cp);
+        const result_type __m = static_cast<result_type>(_Mp);
+        return (__a * __x + __c) % __m;
+    }
+};
+
+template <unsigned long long _Ap, unsigned long long _Cp>
+struct __lce_ta<_Ap, _Cp, 0, unsigned(~0), false>
+{
+    typedef unsigned result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    static result_type next(result_type __x)
+    {
+        const result_type __a = static_cast<result_type>(_Ap);
+        const result_type __c = static_cast<result_type>(_Cp);
+        return __a * __x + __c;
+    }
+};
+
+// 16
+
+template <unsigned long long __a, unsigned long long __c, unsigned long long __m, bool __b>
+struct __lce_ta<__a, __c, __m, (unsigned short)(~0), __b>
+{
+    typedef unsigned short result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    static result_type next(result_type __x)
+    {
+        return static_cast<result_type>(__lce_ta<__a, __c, __m, unsigned(~0)>::next(__x));
+    }
+};
+
+template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+class _LIBCPP_TEMPLATE_VIS linear_congruential_engine;
+
+template <class _CharT, class _Traits,
+          class _Up, _Up _Ap, _Up _Cp, _Up _Np>
+_LIBCPP_INLINE_VISIBILITY
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const linear_congruential_engine<_Up, _Ap, _Cp, _Np>&);
+
+template <class _CharT, class _Traits,
+          class _Up, _Up _Ap, _Up _Cp, _Up _Np>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           linear_congruential_engine<_Up, _Ap, _Cp, _Np>& __x);
+
+template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+class _LIBCPP_TEMPLATE_VIS linear_congruential_engine
+{
+public:
+    // types
+    typedef _UIntType result_type;
+
+private:
+    result_type __x_;
+
+    static _LIBCPP_CONSTEXPR const result_type _Mp = result_type(~0);
+
+    static_assert(__m == 0 || __a < __m, "linear_congruential_engine invalid parameters");
+    static_assert(__m == 0 || __c < __m, "linear_congruential_engine invalid parameters");
+    static_assert(is_unsigned<_UIntType>::value, "_UIntType must be unsigned type");
+public:
+    static _LIBCPP_CONSTEXPR const result_type _Min = __c == 0u ? 1u: 0u;
+    static _LIBCPP_CONSTEXPR const result_type _Max = __m - 1u;
+    static_assert(_Min < _Max,           "linear_congruential_engine invalid parameters");
+
+    // engine characteristics
+    static _LIBCPP_CONSTEXPR const result_type multiplier = __a;
+    static _LIBCPP_CONSTEXPR const result_type increment = __c;
+    static _LIBCPP_CONSTEXPR const result_type modulus = __m;
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
+    static _LIBCPP_CONSTEXPR const result_type default_seed = 1u;
+
+    // constructors and seeding functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    linear_congruential_engine() : linear_congruential_engine(default_seed) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit linear_congruential_engine(result_type __s) { seed(__s); }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit linear_congruential_engine(result_type __s = default_seed) {
+      seed(__s);
+    }
+#endif
+    template<class _Sseq>
+        _LIBCPP_INLINE_VISIBILITY
+        explicit linear_congruential_engine(_Sseq& __q,
+        typename enable_if<__is_seed_sequence<_Sseq, linear_congruential_engine>::value>::type* = 0)
+        {seed(__q);}
+    _LIBCPP_INLINE_VISIBILITY
+    void seed(result_type __s = default_seed)
+        {seed(integral_constant<bool, __m == 0>(),
+              integral_constant<bool, __c == 0>(), __s);}
+    template<class _Sseq>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            __is_seed_sequence<_Sseq, linear_congruential_engine>::value,
+            void
+        >::type
+        seed(_Sseq& __q)
+            {__seed(__q, integral_constant<unsigned,
+                1 + (__m == 0 ? (sizeof(result_type) * __CHAR_BIT__ - 1)/32
+                             :  (__m > 0x100000000ull))>());}
+
+    // generating functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type operator()()
+        {return __x_ = static_cast<result_type>(__lce_ta<__a, __c, __m, _Mp>::next(__x_));}
+    _LIBCPP_INLINE_VISIBILITY
+    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const linear_congruential_engine& __x,
+                    const linear_congruential_engine& __y)
+        {return __x.__x_ == __y.__x_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const linear_congruential_engine& __x,
+                    const linear_congruential_engine& __y)
+        {return !(__x == __y);}
+
+private:
+
+    _LIBCPP_INLINE_VISIBILITY
+    void seed(true_type, true_type, result_type __s) {__x_ = __s == 0 ? 1 : __s;}
+    _LIBCPP_INLINE_VISIBILITY
+    void seed(true_type, false_type, result_type __s) {__x_ = __s;}
+    _LIBCPP_INLINE_VISIBILITY
+    void seed(false_type, true_type, result_type __s) {__x_ = __s % __m == 0 ?
+                                                                 1 : __s % __m;}
+    _LIBCPP_INLINE_VISIBILITY
+    void seed(false_type, false_type, result_type __s) {__x_ = __s % __m;}
+
+    template<class _Sseq>
+        void __seed(_Sseq& __q, integral_constant<unsigned, 1>);
+    template<class _Sseq>
+        void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
+
+    template <class _CharT, class _Traits,
+              class _Up, _Up _Ap, _Up _Cp, _Up _Np>
+    friend
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+               const linear_congruential_engine<_Up, _Ap, _Cp, _Np>&);
+
+    template <class _CharT, class _Traits,
+              class _Up, _Up _Ap, _Up _Cp, _Up _Np>
+    friend
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is,
+               linear_congruential_engine<_Up, _Ap, _Cp, _Np>& __x);
+};
+
+template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+    _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
+    linear_congruential_engine<_UIntType, __a, __c, __m>::multiplier;
+
+template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+    _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
+    linear_congruential_engine<_UIntType, __a, __c, __m>::increment;
+
+template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+    _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
+    linear_congruential_engine<_UIntType, __a, __c, __m>::modulus;
+
+template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+    _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
+    linear_congruential_engine<_UIntType, __a, __c, __m>::default_seed;
+
+template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+template<class _Sseq>
+void
+linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q,
+                                                 integral_constant<unsigned, 1>)
+{
+    const unsigned __k = 1;
+    uint32_t __ar[__k+3];
+    __q.generate(__ar, __ar + __k + 3);
+    result_type __s = static_cast<result_type>(__ar[3] % __m);
+    __x_ = __c == 0 && __s == 0 ? result_type(1) : __s;
+}
+
+template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+template<class _Sseq>
+void
+linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q,
+                                                 integral_constant<unsigned, 2>)
+{
+    const unsigned __k = 2;
+    uint32_t __ar[__k+3];
+    __q.generate(__ar, __ar + __k + 3);
+    result_type __s = static_cast<result_type>((__ar[3] +
+                                              ((uint64_t)__ar[4] << 32)) % __m);
+    __x_ = __c == 0 && __s == 0 ? result_type(1) : __s;
+}
+
+template <class _CharT, class _Traits,
+          class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const linear_congruential_engine<_UIntType, __a, __c, __m>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _Ostream;
+    __os.flags(_Ostream::dec | _Ostream::left);
+    __os.fill(__os.widen(' '));
+    return __os << __x.__x_;
+}
+
+template <class _CharT, class _Traits,
+          class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           linear_congruential_engine<_UIntType, __a, __c, __m>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    _UIntType __t;
+    __is >> __t;
+    if (!__is.fail())
+        __x.__x_ = __t;
+    return __is;
+}
+
+typedef linear_congruential_engine<uint_fast32_t, 16807, 0, 2147483647>
+                                                                   minstd_rand0;
+typedef linear_congruential_engine<uint_fast32_t, 48271, 0, 2147483647>
+                                                                    minstd_rand;
+typedef minstd_rand                                       default_random_engine;
+// mersenne_twister_engine
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+class _LIBCPP_TEMPLATE_VIS mersenne_twister_engine;
+
+template <class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
+          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
+          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
+bool
+operator==(const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
+           const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
+
+template <class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
+          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
+          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
+           const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
+
+template <class _CharT, class _Traits,
+          class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
+          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
+          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
+
+template <class _CharT, class _Traits,
+          class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
+          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
+          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                   _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+class _LIBCPP_TEMPLATE_VIS mersenne_twister_engine
+{
+public:
+    // types
+    typedef _UIntType result_type;
+
+private:
+    result_type __x_[__n];
+    size_t      __i_;
+
+    static_assert(  0 <  __m, "mersenne_twister_engine invalid parameters");
+    static_assert(__m <= __n, "mersenne_twister_engine invalid parameters");
+    static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
+    static_assert(__w <= _Dt, "mersenne_twister_engine invalid parameters");
+    static_assert(  2 <= __w, "mersenne_twister_engine invalid parameters");
+    static_assert(__r <= __w, "mersenne_twister_engine invalid parameters");
+    static_assert(__u <= __w, "mersenne_twister_engine invalid parameters");
+    static_assert(__s <= __w, "mersenne_twister_engine invalid parameters");
+    static_assert(__t <= __w, "mersenne_twister_engine invalid parameters");
+    static_assert(__l <= __w, "mersenne_twister_engine invalid parameters");
+public:
+    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning( push )
+#pragma warning( disable: 4293 )
+#endif // _LIBCPP_COMPILER_MSVC
+    static _LIBCPP_CONSTEXPR const result_type _Max = __w == _Dt ? result_type(~0) :
+                                                      (result_type(1) << __w) - result_type(1);
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif // _LIBCPP_COMPILER_MSVC
+    static_assert(_Min < _Max, "mersenne_twister_engine invalid parameters");
+    static_assert(__a <= _Max, "mersenne_twister_engine invalid parameters");
+    static_assert(__b <= _Max, "mersenne_twister_engine invalid parameters");
+    static_assert(__c <= _Max, "mersenne_twister_engine invalid parameters");
+    static_assert(__d <= _Max, "mersenne_twister_engine invalid parameters");
+    static_assert(__f <= _Max, "mersenne_twister_engine invalid parameters");
+
+    // engine characteristics
+    static _LIBCPP_CONSTEXPR const size_t word_size = __w;
+    static _LIBCPP_CONSTEXPR const size_t state_size = __n;
+    static _LIBCPP_CONSTEXPR const size_t shift_size = __m;
+    static _LIBCPP_CONSTEXPR const size_t mask_bits = __r;
+    static _LIBCPP_CONSTEXPR const result_type xor_mask = __a;
+    static _LIBCPP_CONSTEXPR const size_t tempering_u = __u;
+    static _LIBCPP_CONSTEXPR const result_type tempering_d = __d;
+    static _LIBCPP_CONSTEXPR const size_t tempering_s = __s;
+    static _LIBCPP_CONSTEXPR const result_type tempering_b = __b;
+    static _LIBCPP_CONSTEXPR const size_t tempering_t = __t;
+    static _LIBCPP_CONSTEXPR const result_type tempering_c = __c;
+    static _LIBCPP_CONSTEXPR const size_t tempering_l = __l;
+    static _LIBCPP_CONSTEXPR const result_type initialization_multiplier = __f;
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
+    static _LIBCPP_CONSTEXPR const result_type default_seed = 5489u;
+
+    // constructors and seeding functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    mersenne_twister_engine() : mersenne_twister_engine(default_seed) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit mersenne_twister_engine(result_type __sd) { seed(__sd); }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit mersenne_twister_engine(result_type __sd = default_seed) {
+      seed(__sd);
+    }
+#endif
+    template<class _Sseq>
+        _LIBCPP_INLINE_VISIBILITY
+        explicit mersenne_twister_engine(_Sseq& __q,
+        typename enable_if<__is_seed_sequence<_Sseq, mersenne_twister_engine>::value>::type* = 0)
+        {seed(__q);}
+    void seed(result_type __sd = default_seed);
+    template<class _Sseq>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            __is_seed_sequence<_Sseq, mersenne_twister_engine>::value,
+            void
+        >::type
+        seed(_Sseq& __q)
+            {__seed(__q, integral_constant<unsigned, 1 + (__w - 1) / 32>());}
+
+    // generating functions
+    result_type operator()();
+    _LIBCPP_INLINE_VISIBILITY
+    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
+
+    template <class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
+              _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
+              _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
+    friend
+    bool
+    operator==(const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
+               const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
+
+    template <class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
+              _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
+              _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
+    friend
+    bool
+    operator!=(const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
+               const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
+
+    template <class _CharT, class _Traits,
+              class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
+              _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
+              _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
+    friend
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+               const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
+
+    template <class _CharT, class _Traits,
+              class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
+              _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
+              _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
+    friend
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is,
+               mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                       _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
+private:
+
+    template<class _Sseq>
+        void __seed(_Sseq& __q, integral_constant<unsigned, 1>);
+    template<class _Sseq>
+        void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
+
+    template <size_t __count>
+        _LIBCPP_INLINE_VISIBILITY
+        static
+        typename enable_if
+        <
+            __count < __w,
+            result_type
+        >::type
+        __lshift(result_type __x) {return (__x << __count) & _Max;}
+
+    template <size_t __count>
+        _LIBCPP_INLINE_VISIBILITY
+        static
+        typename enable_if
+        <
+            (__count >= __w),
+            result_type
+        >::type
+        __lshift(result_type) {return result_type(0);}
+
+    template <size_t __count>
+        _LIBCPP_INLINE_VISIBILITY
+        static
+        typename enable_if
+        <
+            __count < _Dt,
+            result_type
+        >::type
+        __rshift(result_type __x) {return __x >> __count;}
+
+    template <size_t __count>
+        _LIBCPP_INLINE_VISIBILITY
+        static
+        typename enable_if
+        <
+            (__count >= _Dt),
+            result_type
+        >::type
+        __rshift(result_type) {return result_type(0);}
+};
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::word_size;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::state_size;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::shift_size;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::mask_bits;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::xor_mask;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_u;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_d;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_s;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_b;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_t;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_c;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const size_t
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_l;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::initialization_multiplier;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::default_seed;
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+void
+mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
+    __t, __c, __l, __f>::seed(result_type __sd)
+    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+{   // __w >= 2
+    __x_[0] = __sd & _Max;
+    for (size_t __i = 1; __i < __n; ++__i)
+        __x_[__i] = (__f * (__x_[__i-1] ^ __rshift<__w - 2>(__x_[__i-1])) + __i) & _Max;
+    __i_ = 0;
+}
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+template<class _Sseq>
+void
+mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
+    __t, __c, __l, __f>::__seed(_Sseq& __q, integral_constant<unsigned, 1>)
+{
+    const unsigned __k = 1;
+    uint32_t __ar[__n * __k];
+    __q.generate(__ar, __ar + __n * __k);
+    for (size_t __i = 0; __i < __n; ++__i)
+        __x_[__i] = static_cast<result_type>(__ar[__i] & _Max);
+    const result_type __mask = __r == _Dt ? result_type(~0) :
+                                       (result_type(1) << __r) - result_type(1);
+    __i_ = 0;
+    if ((__x_[0] & ~__mask) == 0)
+    {
+        for (size_t __i = 1; __i < __n; ++__i)
+            if (__x_[__i] != 0)
+                return;
+        __x_[0] = result_type(1) << (__w - 1);
+    }
+}
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+template<class _Sseq>
+void
+mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
+    __t, __c, __l, __f>::__seed(_Sseq& __q, integral_constant<unsigned, 2>)
+{
+    const unsigned __k = 2;
+    uint32_t __ar[__n * __k];
+    __q.generate(__ar, __ar + __n * __k);
+    for (size_t __i = 0; __i < __n; ++__i)
+        __x_[__i] = static_cast<result_type>(
+            (__ar[2 * __i] + ((uint64_t)__ar[2 * __i + 1] << 32)) & _Max);
+    const result_type __mask = __r == _Dt ? result_type(~0) :
+                                       (result_type(1) << __r) - result_type(1);
+    __i_ = 0;
+    if ((__x_[0] & ~__mask) == 0)
+    {
+        for (size_t __i = 1; __i < __n; ++__i)
+            if (__x_[__i] != 0)
+                return;
+        __x_[0] = result_type(1) << (__w - 1);
+    }
+}
+
+template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
+          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
+_UIntType
+mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
+    __t, __c, __l, __f>::operator()()
+{
+    const size_t __j = (__i_ + 1) % __n;
+    const result_type __mask = __r == _Dt ? result_type(~0) :
+                                       (result_type(1) << __r) - result_type(1);
+    const result_type _Yp = (__x_[__i_] & ~__mask) | (__x_[__j] & __mask);
+    const size_t __k = (__i_ + __m) % __n;
+    __x_[__i_] = __x_[__k] ^ __rshift<1>(_Yp) ^ (__a * (_Yp & 1));
+    result_type __z = __x_[__i_] ^ (__rshift<__u>(__x_[__i_]) & __d);
+    __i_ = __j;
+    __z ^= __lshift<__s>(__z) & __b;
+    __z ^= __lshift<__t>(__z) & __c;
+    return __z ^ __rshift<__l>(__z);
+}
+
+template <class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
+          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
+          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
+bool
+operator==(const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
+           const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y)
+{
+    if (__x.__i_ == __y.__i_)
+        return _VSTD::equal(__x.__x_, __x.__x_ + _Np, __y.__x_);
+    if (__x.__i_ == 0 || __y.__i_ == 0)
+    {
+        size_t __j = _VSTD::min(_Np - __x.__i_, _Np - __y.__i_);
+        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + __x.__i_ + __j,
+                         __y.__x_ + __y.__i_))
+            return false;
+        if (__x.__i_ == 0)
+            return _VSTD::equal(__x.__x_ + __j, __x.__x_ + _Np, __y.__x_);
+        return _VSTD::equal(__x.__x_, __x.__x_ + (_Np - __j), __y.__x_ + __j);
+    }
+    if (__x.__i_ < __y.__i_)
+    {
+        size_t __j = _Np - __y.__i_;
+        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + (__x.__i_ + __j),
+                         __y.__x_ + __y.__i_))
+            return false;
+        if (!_VSTD::equal(__x.__x_ + (__x.__i_ + __j), __x.__x_ + _Np,
+                         __y.__x_))
+            return false;
+        return _VSTD::equal(__x.__x_, __x.__x_ + __x.__i_,
+                           __y.__x_ + (_Np - (__x.__i_ + __j)));
+    }
+    size_t __j = _Np - __x.__i_;
+    if (!_VSTD::equal(__y.__x_ + __y.__i_, __y.__x_ + (__y.__i_ + __j),
+                     __x.__x_ + __x.__i_))
+        return false;
+    if (!_VSTD::equal(__y.__x_ + (__y.__i_ + __j), __y.__x_ + _Np,
+                     __x.__x_))
+        return false;
+    return _VSTD::equal(__y.__x_, __y.__x_ + __y.__i_,
+                       __x.__x_ + (_Np - (__y.__i_ + __j)));
+}
+
+template <class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
+          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
+          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
+           const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _CharT, class _Traits,
+          class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
+          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
+          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _Ostream;
+    __os.flags(_Ostream::dec | _Ostream::left);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    __os << __x.__x_[__x.__i_];
+    for (size_t __j = __x.__i_ + 1; __j < _Np; ++__j)
+        __os << __sp << __x.__x_[__j];
+    for (size_t __j = 0; __j < __x.__i_; ++__j)
+        __os << __sp << __x.__x_[__j];
+    return __os;
+}
+
+template <class _CharT, class _Traits,
+          class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
+          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
+          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
+                                   _Bp, _Tp, _Cp, _Lp, _Fp>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    _UInt __t[_Np];
+    for (size_t __i = 0; __i < _Np; ++__i)
+        __is >> __t[__i];
+    if (!__is.fail())
+    {
+        for (size_t __i = 0; __i < _Np; ++__i)
+            __x.__x_[__i] = __t[__i];
+        __x.__i_ = 0;
+    }
+    return __is;
+}
+
+typedef mersenne_twister_engine<uint_fast32_t, 32, 624, 397, 31,
+                                0x9908b0df, 11, 0xffffffff,
+                                7,  0x9d2c5680,
+                                15, 0xefc60000,
+                                18, 1812433253>                         mt19937;
+typedef mersenne_twister_engine<uint_fast64_t, 64, 312, 156, 31,
+                                0xb5026f5aa96619e9ULL, 29, 0x5555555555555555ULL,
+                                17, 0x71d67fffeda60000ULL,
+                                37, 0xfff7eee000000000ULL,
+                                43, 6364136223846793005ULL>          mt19937_64;
+
+// subtract_with_carry_engine
+
+template<class _UIntType, size_t __w, size_t __s, size_t __r>
+class _LIBCPP_TEMPLATE_VIS subtract_with_carry_engine;
+
+template<class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
+bool
+operator==(
+    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x,
+    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y);
+
+template<class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
+_LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(
+    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x,
+    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y);
+
+template <class _CharT, class _Traits,
+          class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x);
+
+template <class _CharT, class _Traits,
+          class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x);
+
+template<class _UIntType, size_t __w, size_t __s, size_t __r>
+class _LIBCPP_TEMPLATE_VIS subtract_with_carry_engine
+{
+public:
+    // types
+    typedef _UIntType result_type;
+
+private:
+    result_type __x_[__r];
+    result_type  __c_;
+    size_t      __i_;
+
+    static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
+    static_assert(  0 <  __w, "subtract_with_carry_engine invalid parameters");
+    static_assert(__w <= _Dt, "subtract_with_carry_engine invalid parameters");
+    static_assert(  0 <  __s, "subtract_with_carry_engine invalid parameters");
+    static_assert(__s <  __r, "subtract_with_carry_engine invalid parameters");
+public:
+    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
+    static _LIBCPP_CONSTEXPR const result_type _Max = __w == _Dt ? result_type(~0) :
+                                                      (result_type(1) << __w) - result_type(1);
+    static_assert(_Min < _Max, "subtract_with_carry_engine invalid parameters");
+
+    // engine characteristics
+    static _LIBCPP_CONSTEXPR const size_t word_size = __w;
+    static _LIBCPP_CONSTEXPR const size_t short_lag = __s;
+    static _LIBCPP_CONSTEXPR const size_t long_lag = __r;
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
+    static _LIBCPP_CONSTEXPR const result_type default_seed = 19780503u;
+
+    // constructors and seeding functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    subtract_with_carry_engine() : subtract_with_carry_engine(default_seed) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit subtract_with_carry_engine(result_type __sd) { seed(__sd); }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit subtract_with_carry_engine(result_type __sd = default_seed) {
+      seed(__sd);
+    }
+#endif
+    template<class _Sseq>
+        _LIBCPP_INLINE_VISIBILITY
+        explicit subtract_with_carry_engine(_Sseq& __q,
+        typename enable_if<__is_seed_sequence<_Sseq, subtract_with_carry_engine>::value>::type* = 0)
+        {seed(__q);}
+    _LIBCPP_INLINE_VISIBILITY
+    void seed(result_type __sd = default_seed)
+        {seed(__sd, integral_constant<unsigned, 1 + (__w - 1) / 32>());}
+    template<class _Sseq>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            __is_seed_sequence<_Sseq, subtract_with_carry_engine>::value,
+            void
+        >::type
+        seed(_Sseq& __q)
+            {__seed(__q, integral_constant<unsigned, 1 + (__w - 1) / 32>());}
+
+    // generating functions
+    result_type operator()();
+    _LIBCPP_INLINE_VISIBILITY
+    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
+
+    template<class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
+    friend
+    bool
+    operator==(
+        const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x,
+        const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y);
+
+    template<class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
+    friend
+    bool
+    operator!=(
+        const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x,
+        const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y);
+
+    template <class _CharT, class _Traits,
+              class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
+    friend
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+               const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x);
+
+    template <class _CharT, class _Traits,
+              class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
+    friend
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is,
+               subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x);
+
+private:
+
+    void seed(result_type __sd, integral_constant<unsigned, 1>);
+    void seed(result_type __sd, integral_constant<unsigned, 2>);
+    template<class _Sseq>
+        void __seed(_Sseq& __q, integral_constant<unsigned, 1>);
+    template<class _Sseq>
+        void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
+};
+
+template<class _UIntType, size_t __w, size_t __s, size_t __r>
+    _LIBCPP_CONSTEXPR const size_t subtract_with_carry_engine<_UIntType, __w, __s, __r>::word_size;
+
+template<class _UIntType, size_t __w, size_t __s, size_t __r>
+    _LIBCPP_CONSTEXPR const size_t subtract_with_carry_engine<_UIntType, __w, __s, __r>::short_lag;
+
+template<class _UIntType, size_t __w, size_t __s, size_t __r>
+    _LIBCPP_CONSTEXPR const size_t subtract_with_carry_engine<_UIntType, __w, __s, __r>::long_lag;
+
+template<class _UIntType, size_t __w, size_t __s, size_t __r>
+    _LIBCPP_CONSTEXPR const typename subtract_with_carry_engine<_UIntType, __w, __s, __r>::result_type
+    subtract_with_carry_engine<_UIntType, __w, __s, __r>::default_seed;
+
+template<class _UIntType, size_t __w, size_t __s, size_t __r>
+void
+subtract_with_carry_engine<_UIntType, __w, __s, __r>::seed(result_type __sd,
+        integral_constant<unsigned, 1>)
+{
+    linear_congruential_engine<result_type, 40014u, 0u, 2147483563u>
+        __e(__sd == 0u ? default_seed : __sd);
+    for (size_t __i = 0; __i < __r; ++__i)
+        __x_[__i] = static_cast<result_type>(__e() & _Max);
+    __c_ = __x_[__r-1] == 0;
+    __i_ = 0;
+}
+
+template<class _UIntType, size_t __w, size_t __s, size_t __r>
+void
+subtract_with_carry_engine<_UIntType, __w, __s, __r>::seed(result_type __sd,
+        integral_constant<unsigned, 2>)
+{
+    linear_congruential_engine<result_type, 40014u, 0u, 2147483563u>
+        __e(__sd == 0u ? default_seed : __sd);
+    for (size_t __i = 0; __i < __r; ++__i)
+    {
+        result_type __e0 = __e();
+        __x_[__i] = static_cast<result_type>(
+                                    (__e0 + ((uint64_t)__e() << 32)) & _Max);
+    }
+    __c_ = __x_[__r-1] == 0;
+    __i_ = 0;
+}
+
+template<class _UIntType, size_t __w, size_t __s, size_t __r>
+template<class _Sseq>
+void
+subtract_with_carry_engine<_UIntType, __w, __s, __r>::__seed(_Sseq& __q,
+        integral_constant<unsigned, 1>)
+{
+    const unsigned __k = 1;
+    uint32_t __ar[__r * __k];
+    __q.generate(__ar, __ar + __r * __k);
+    for (size_t __i = 0; __i < __r; ++__i)
+        __x_[__i] = static_cast<result_type>(__ar[__i] & _Max);
+    __c_ = __x_[__r-1] == 0;
+    __i_ = 0;
+}
+
+template<class _UIntType, size_t __w, size_t __s, size_t __r>
+template<class _Sseq>
+void
+subtract_with_carry_engine<_UIntType, __w, __s, __r>::__seed(_Sseq& __q,
+        integral_constant<unsigned, 2>)
+{
+    const unsigned __k = 2;
+    uint32_t __ar[__r * __k];
+    __q.generate(__ar, __ar + __r * __k);
+    for (size_t __i = 0; __i < __r; ++__i)
+        __x_[__i] = static_cast<result_type>(
+                  (__ar[2 * __i] + ((uint64_t)__ar[2 * __i + 1] << 32)) & _Max);
+    __c_ = __x_[__r-1] == 0;
+    __i_ = 0;
+}
+
+template<class _UIntType, size_t __w, size_t __s, size_t __r>
+_UIntType
+subtract_with_carry_engine<_UIntType, __w, __s, __r>::operator()()
+{
+    const result_type& __xs = __x_[(__i_ + (__r - __s)) % __r];
+    result_type& __xr = __x_[__i_];
+    result_type __new_c = __c_ == 0 ? __xs < __xr : __xs != 0 ? __xs <= __xr : 1;
+    __xr = (__xs - __xr - __c_) & _Max;
+    __c_ = __new_c;
+    __i_ = (__i_ + 1) % __r;
+    return __xr;
+}
+
+template<class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
+bool
+operator==(
+    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x,
+    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y)
+{
+    if (__x.__c_ != __y.__c_)
+        return false;
+    if (__x.__i_ == __y.__i_)
+        return _VSTD::equal(__x.__x_, __x.__x_ + _Rp, __y.__x_);
+    if (__x.__i_ == 0 || __y.__i_ == 0)
+    {
+        size_t __j = _VSTD::min(_Rp - __x.__i_, _Rp - __y.__i_);
+        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + __x.__i_ + __j,
+                         __y.__x_ + __y.__i_))
+            return false;
+        if (__x.__i_ == 0)
+            return _VSTD::equal(__x.__x_ + __j, __x.__x_ + _Rp, __y.__x_);
+        return _VSTD::equal(__x.__x_, __x.__x_ + (_Rp - __j), __y.__x_ + __j);
+    }
+    if (__x.__i_ < __y.__i_)
+    {
+        size_t __j = _Rp - __y.__i_;
+        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + (__x.__i_ + __j),
+                         __y.__x_ + __y.__i_))
+            return false;
+        if (!_VSTD::equal(__x.__x_ + (__x.__i_ + __j), __x.__x_ + _Rp,
+                         __y.__x_))
+            return false;
+        return _VSTD::equal(__x.__x_, __x.__x_ + __x.__i_,
+                           __y.__x_ + (_Rp - (__x.__i_ + __j)));
+    }
+    size_t __j = _Rp - __x.__i_;
+    if (!_VSTD::equal(__y.__x_ + __y.__i_, __y.__x_ + (__y.__i_ + __j),
+                     __x.__x_ + __x.__i_))
+        return false;
+    if (!_VSTD::equal(__y.__x_ + (__y.__i_ + __j), __y.__x_ + _Rp,
+                     __x.__x_))
+        return false;
+    return _VSTD::equal(__y.__x_, __y.__x_ + __y.__i_,
+                       __x.__x_ + (_Rp - (__y.__i_ + __j)));
+}
+
+template<class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(
+    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x,
+    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _CharT, class _Traits,
+          class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _Ostream;
+    __os.flags(_Ostream::dec | _Ostream::left);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    __os << __x.__x_[__x.__i_];
+    for (size_t __j = __x.__i_ + 1; __j < _Rp; ++__j)
+        __os << __sp << __x.__x_[__j];
+    for (size_t __j = 0; __j < __x.__i_; ++__j)
+        __os << __sp << __x.__x_[__j];
+    __os << __sp << __x.__c_;
+    return __os;
+}
+
+template <class _CharT, class _Traits,
+          class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    _UInt __t[_Rp+1];
+    for (size_t __i = 0; __i < _Rp+1; ++__i)
+        __is >> __t[__i];
+    if (!__is.fail())
+    {
+        for (size_t __i = 0; __i < _Rp; ++__i)
+            __x.__x_[__i] = __t[__i];
+        __x.__c_ = __t[_Rp];
+        __x.__i_ = 0;
+    }
+    return __is;
+}
+
+typedef subtract_with_carry_engine<uint_fast32_t, 24, 10, 24>     ranlux24_base;
+typedef subtract_with_carry_engine<uint_fast64_t, 48,  5, 12>     ranlux48_base;
+
+// discard_block_engine
+
+template<class _Engine, size_t __p, size_t __r>
+class _LIBCPP_TEMPLATE_VIS discard_block_engine
+{
+    _Engine __e_;
+    int     __n_;
+
+    static_assert(  0 <  __r, "discard_block_engine invalid parameters");
+    static_assert(__r <= __p, "discard_block_engine invalid parameters");
+    static_assert(__r <= INT_MAX, "discard_block_engine invalid parameters");
+public:
+    // types
+    typedef typename _Engine::result_type result_type;
+
+    // engine characteristics
+    static _LIBCPP_CONSTEXPR const size_t block_size = __p;
+    static _LIBCPP_CONSTEXPR const size_t used_block = __r;
+
+#ifdef _LIBCPP_CXX03_LANG
+    static const result_type _Min = _Engine::_Min;
+    static const result_type _Max = _Engine::_Max;
+#else
+    static _LIBCPP_CONSTEXPR const result_type _Min = _Engine::min();
+    static _LIBCPP_CONSTEXPR const result_type _Max = _Engine::max();
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type min() { return _Engine::min(); }
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type max() { return _Engine::max(); }
+
+    // constructors and seeding functions
+    _LIBCPP_INLINE_VISIBILITY
+    discard_block_engine() : __n_(0) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit discard_block_engine(const _Engine& __e)
+        : __e_(__e), __n_(0) {}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    explicit discard_block_engine(_Engine&& __e)
+        : __e_(_VSTD::move(__e)), __n_(0) {}
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    explicit discard_block_engine(result_type __sd) : __e_(__sd), __n_(0) {}
+    template<class _Sseq>
+        _LIBCPP_INLINE_VISIBILITY
+        explicit discard_block_engine(_Sseq& __q,
+        typename enable_if<__is_seed_sequence<_Sseq, discard_block_engine>::value &&
+                           !is_convertible<_Sseq, _Engine>::value>::type* = 0)
+        : __e_(__q), __n_(0) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void seed() {__e_.seed(); __n_ = 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    void seed(result_type __sd) {__e_.seed(__sd); __n_ = 0;}
+    template<class _Sseq>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            __is_seed_sequence<_Sseq, discard_block_engine>::value,
+            void
+        >::type
+        seed(_Sseq& __q) {__e_.seed(__q); __n_ = 0;}
+
+    // generating functions
+    result_type operator()();
+    _LIBCPP_INLINE_VISIBILITY
+    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    const _Engine& base() const _NOEXCEPT {return __e_;}
+
+    template<class _Eng, size_t _Pp, size_t _Rp>
+    friend
+    bool
+    operator==(
+        const discard_block_engine<_Eng, _Pp, _Rp>& __x,
+        const discard_block_engine<_Eng, _Pp, _Rp>& __y);
+
+    template<class _Eng, size_t _Pp, size_t _Rp>
+    friend
+    bool
+    operator!=(
+        const discard_block_engine<_Eng, _Pp, _Rp>& __x,
+        const discard_block_engine<_Eng, _Pp, _Rp>& __y);
+
+    template <class _CharT, class _Traits,
+              class _Eng, size_t _Pp, size_t _Rp>
+    friend
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+               const discard_block_engine<_Eng, _Pp, _Rp>& __x);
+
+    template <class _CharT, class _Traits,
+              class _Eng, size_t _Pp, size_t _Rp>
+    friend
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is,
+               discard_block_engine<_Eng, _Pp, _Rp>& __x);
+};
+
+template<class _Engine, size_t __p, size_t __r>
+    _LIBCPP_CONSTEXPR const size_t discard_block_engine<_Engine, __p, __r>::block_size;
+
+template<class _Engine, size_t __p, size_t __r>
+    _LIBCPP_CONSTEXPR const size_t discard_block_engine<_Engine, __p, __r>::used_block;
+
+template<class _Engine, size_t __p, size_t __r>
+typename discard_block_engine<_Engine, __p, __r>::result_type
+discard_block_engine<_Engine, __p, __r>::operator()()
+{
+    if (__n_ >= static_cast<int>(__r))
+    {
+        __e_.discard(__p - __r);
+        __n_ = 0;
+    }
+    ++__n_;
+    return __e_();
+}
+
+template<class _Eng, size_t _Pp, size_t _Rp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const discard_block_engine<_Eng, _Pp, _Rp>& __x,
+           const discard_block_engine<_Eng, _Pp, _Rp>& __y)
+{
+    return __x.__n_ == __y.__n_ && __x.__e_ == __y.__e_;
+}
+
+template<class _Eng, size_t _Pp, size_t _Rp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const discard_block_engine<_Eng, _Pp, _Rp>& __x,
+           const discard_block_engine<_Eng, _Pp, _Rp>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _CharT, class _Traits,
+          class _Eng, size_t _Pp, size_t _Rp>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const discard_block_engine<_Eng, _Pp, _Rp>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _Ostream;
+    __os.flags(_Ostream::dec | _Ostream::left);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    return __os << __x.__e_ << __sp << __x.__n_;
+}
+
+template <class _CharT, class _Traits,
+          class _Eng, size_t _Pp, size_t _Rp>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           discard_block_engine<_Eng, _Pp, _Rp>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    _Eng __e;
+    int __n;
+    __is >> __e >> __n;
+    if (!__is.fail())
+    {
+        __x.__e_ = __e;
+        __x.__n_ = __n;
+    }
+    return __is;
+}
+
+typedef discard_block_engine<ranlux24_base, 223, 23> ranlux24;
+typedef discard_block_engine<ranlux48_base, 389, 11> ranlux48;
+
+// independent_bits_engine
+
+template<class _Engine, size_t __w, class _UIntType>
+class _LIBCPP_TEMPLATE_VIS independent_bits_engine
+{
+    template <class _UInt, _UInt _R0, size_t _Wp, size_t _Mp>
+    class __get_n
+    {
+        static _LIBCPP_CONSTEXPR const size_t _Dt = numeric_limits<_UInt>::digits;
+        static _LIBCPP_CONSTEXPR const size_t _Np = _Wp / _Mp + (_Wp % _Mp != 0);
+        static _LIBCPP_CONSTEXPR const size_t _W0 = _Wp / _Np;
+        static _LIBCPP_CONSTEXPR const _UInt _Y0 = _W0 >= _Dt ? 0 : (_R0 >> _W0) << _W0;
+    public:
+        static _LIBCPP_CONSTEXPR const size_t value = _R0 - _Y0 > _Y0 / _Np ? _Np + 1 : _Np;
+    };
+public:
+    // types
+    typedef _UIntType result_type;
+
+private:
+    _Engine __e_;
+
+    static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
+    static_assert(  0 <  __w, "independent_bits_engine invalid parameters");
+    static_assert(__w <= _Dt, "independent_bits_engine invalid parameters");
+
+    typedef typename _Engine::result_type _Engine_result_type;
+    typedef typename conditional
+        <
+            sizeof(_Engine_result_type) <= sizeof(result_type),
+                result_type,
+                _Engine_result_type
+        >::type _Working_result_type;
+#ifdef _LIBCPP_CXX03_LANG
+    static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min
+                                          + _Working_result_type(1);
+#else
+    static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min()
+                                                            + _Working_result_type(1);
+#endif
+    static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;
+    static _LIBCPP_CONSTEXPR const size_t __n = __get_n<_Working_result_type, _Rp, __w, __m>::value;
+    static _LIBCPP_CONSTEXPR const size_t __w0 = __w / __n;
+    static _LIBCPP_CONSTEXPR const size_t __n0 = __n - __w % __n;
+    static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
+    static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;
+    static _LIBCPP_CONSTEXPR const _Working_result_type __y0 = __w0 >= _WDt ? 0 :
+                                                               (_Rp >> __w0) << __w0;
+    static _LIBCPP_CONSTEXPR const _Working_result_type __y1 = __w0 >= _WDt - 1 ? 0 :
+                                                               (_Rp >> (__w0+1)) << (__w0+1);
+    static _LIBCPP_CONSTEXPR const _Engine_result_type __mask0 = __w0 > 0 ?
+                                _Engine_result_type(~0) >> (_EDt - __w0) :
+                                _Engine_result_type(0);
+    static _LIBCPP_CONSTEXPR const _Engine_result_type __mask1 = __w0 < _EDt - 1 ?
+                                _Engine_result_type(~0) >> (_EDt - (__w0 + 1)) :
+                                _Engine_result_type(~0);
+public:
+    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning( push )
+#pragma warning( disable: 4293 )
+#endif // _LIBCPP_COMPILER_MSVC
+    static _LIBCPP_CONSTEXPR const result_type _Max = __w == _Dt ? result_type(~0) :
+                                                      (result_type(1) << __w) - result_type(1);
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning( pop )
+#endif // _LIBCPP_COMPILER_MSVC
+
+    static_assert(_Min < _Max, "independent_bits_engine invalid parameters");
+
+    // engine characteristics
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
+
+    // constructors and seeding functions
+    _LIBCPP_INLINE_VISIBILITY
+    independent_bits_engine() {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit independent_bits_engine(const _Engine& __e)
+        : __e_(__e) {}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    explicit independent_bits_engine(_Engine&& __e)
+        : __e_(_VSTD::move(__e)) {}
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    explicit independent_bits_engine(result_type __sd) : __e_(__sd) {}
+    template<class _Sseq>
+        _LIBCPP_INLINE_VISIBILITY
+        explicit independent_bits_engine(_Sseq& __q,
+        typename enable_if<__is_seed_sequence<_Sseq, independent_bits_engine>::value &&
+                           !is_convertible<_Sseq, _Engine>::value>::type* = 0)
+         : __e_(__q) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void seed() {__e_.seed();}
+    _LIBCPP_INLINE_VISIBILITY
+    void seed(result_type __sd) {__e_.seed(__sd);}
+    template<class _Sseq>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            __is_seed_sequence<_Sseq, independent_bits_engine>::value,
+            void
+        >::type
+        seed(_Sseq& __q) {__e_.seed(__q);}
+
+    // generating functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
+    _LIBCPP_INLINE_VISIBILITY
+    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    const _Engine& base() const _NOEXCEPT {return __e_;}
+
+    template<class _Eng, size_t _Wp, class _UInt>
+    friend
+    bool
+    operator==(
+        const independent_bits_engine<_Eng, _Wp, _UInt>& __x,
+        const independent_bits_engine<_Eng, _Wp, _UInt>& __y);
+
+    template<class _Eng, size_t _Wp, class _UInt>
+    friend
+    bool
+    operator!=(
+        const independent_bits_engine<_Eng, _Wp, _UInt>& __x,
+        const independent_bits_engine<_Eng, _Wp, _UInt>& __y);
+
+    template <class _CharT, class _Traits,
+              class _Eng, size_t _Wp, class _UInt>
+    friend
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+               const independent_bits_engine<_Eng, _Wp, _UInt>& __x);
+
+    template <class _CharT, class _Traits,
+              class _Eng, size_t _Wp, class _UInt>
+    friend
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is,
+               independent_bits_engine<_Eng, _Wp, _UInt>& __x);
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    result_type __eval(false_type);
+    result_type __eval(true_type);
+
+    template <size_t __count>
+        _LIBCPP_INLINE_VISIBILITY
+        static
+        typename enable_if
+        <
+            __count < _Dt,
+            result_type
+        >::type
+        __lshift(result_type __x) {return __x << __count;}
+
+    template <size_t __count>
+        _LIBCPP_INLINE_VISIBILITY
+        static
+        typename enable_if
+        <
+            (__count >= _Dt),
+            result_type
+        >::type
+        __lshift(result_type) {return result_type(0);}
+};
+
+template<class _Engine, size_t __w, class _UIntType>
+inline
+_UIntType
+independent_bits_engine<_Engine, __w, _UIntType>::__eval(false_type)
+{
+    return static_cast<result_type>(__e_() & __mask0);
+}
+
+template<class _Engine, size_t __w, class _UIntType>
+_UIntType
+independent_bits_engine<_Engine, __w, _UIntType>::__eval(true_type)
+{
+    result_type _Sp = 0;
+    for (size_t __k = 0; __k < __n0; ++__k)
+    {
+        _Engine_result_type __u;
+        do
+        {
+            __u = __e_() - _Engine::min();
+        } while (__u >= __y0);
+        _Sp = static_cast<result_type>(__lshift<__w0>(_Sp) + (__u & __mask0));
+    }
+    for (size_t __k = __n0; __k < __n; ++__k)
+    {
+        _Engine_result_type __u;
+        do
+        {
+            __u = __e_() - _Engine::min();
+        } while (__u >= __y1);
+        _Sp = static_cast<result_type>(__lshift<__w0+1>(_Sp) + (__u & __mask1));
+    }
+    return _Sp;
+}
+
+template<class _Eng, size_t _Wp, class _UInt>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(
+    const independent_bits_engine<_Eng, _Wp, _UInt>& __x,
+    const independent_bits_engine<_Eng, _Wp, _UInt>& __y)
+{
+    return __x.base() == __y.base();
+}
+
+template<class _Eng, size_t _Wp, class _UInt>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(
+    const independent_bits_engine<_Eng, _Wp, _UInt>& __x,
+    const independent_bits_engine<_Eng, _Wp, _UInt>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _CharT, class _Traits,
+          class _Eng, size_t _Wp, class _UInt>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const independent_bits_engine<_Eng, _Wp, _UInt>& __x)
+{
+    return __os << __x.base();
+}
+
+template <class _CharT, class _Traits,
+          class _Eng, size_t _Wp, class _UInt>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           independent_bits_engine<_Eng, _Wp, _UInt>& __x)
+{
+    _Eng __e;
+    __is >> __e;
+    if (!__is.fail())
+        __x.__e_ = __e;
+    return __is;
+}
+
+// shuffle_order_engine
+
+template <uint64_t _Xp, uint64_t _Yp>
+struct __ugcd
+{
+    static _LIBCPP_CONSTEXPR const uint64_t value = __ugcd<_Yp, _Xp % _Yp>::value;
+};
+
+template <uint64_t _Xp>
+struct __ugcd<_Xp, 0>
+{
+    static _LIBCPP_CONSTEXPR const uint64_t value = _Xp;
+};
+
+template <uint64_t _Np, uint64_t _Dp>
+class __uratio
+{
+    static_assert(_Dp != 0, "__uratio divide by 0");
+    static _LIBCPP_CONSTEXPR const uint64_t __gcd = __ugcd<_Np, _Dp>::value;
+public:
+    static _LIBCPP_CONSTEXPR const uint64_t num = _Np / __gcd;
+    static _LIBCPP_CONSTEXPR const uint64_t den = _Dp / __gcd;
+
+    typedef __uratio<num, den> type;
+};
+
+template<class _Engine, size_t __k>
+class _LIBCPP_TEMPLATE_VIS shuffle_order_engine
+{
+    static_assert(0 < __k, "shuffle_order_engine invalid parameters");
+public:
+    // types
+    typedef typename _Engine::result_type result_type;
+
+private:
+    _Engine __e_;
+    result_type _V_[__k];
+    result_type _Y_;
+
+public:
+    // engine characteristics
+    static _LIBCPP_CONSTEXPR const size_t table_size = __k;
+
+#ifdef _LIBCPP_CXX03_LANG
+    static const result_type _Min = _Engine::_Min;
+    static const result_type _Max = _Engine::_Max;
+#else
+    static _LIBCPP_CONSTEXPR const result_type _Min = _Engine::min();
+    static _LIBCPP_CONSTEXPR const result_type _Max = _Engine::max();
+#endif
+    static_assert(_Min < _Max, "shuffle_order_engine invalid parameters");
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
+
+    static _LIBCPP_CONSTEXPR const unsigned long long _Rp = _Max - _Min + 1ull;
+
+    // constructors and seeding functions
+    _LIBCPP_INLINE_VISIBILITY
+    shuffle_order_engine() {__init();}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit shuffle_order_engine(const _Engine& __e)
+        : __e_(__e) {__init();}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    explicit shuffle_order_engine(_Engine&& __e)
+        : __e_(_VSTD::move(__e)) {__init();}
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    explicit shuffle_order_engine(result_type __sd) : __e_(__sd) {__init();}
+    template<class _Sseq>
+        _LIBCPP_INLINE_VISIBILITY
+        explicit shuffle_order_engine(_Sseq& __q,
+        typename enable_if<__is_seed_sequence<_Sseq, shuffle_order_engine>::value &&
+                           !is_convertible<_Sseq, _Engine>::value>::type* = 0)
+         : __e_(__q) {__init();}
+    _LIBCPP_INLINE_VISIBILITY
+    void seed() {__e_.seed(); __init();}
+    _LIBCPP_INLINE_VISIBILITY
+    void seed(result_type __sd) {__e_.seed(__sd); __init();}
+    template<class _Sseq>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            __is_seed_sequence<_Sseq, shuffle_order_engine>::value,
+            void
+        >::type
+        seed(_Sseq& __q) {__e_.seed(__q); __init();}
+
+    // generating functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
+    _LIBCPP_INLINE_VISIBILITY
+    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    const _Engine& base() const _NOEXCEPT {return __e_;}
+
+private:
+    template<class _Eng, size_t _Kp>
+    friend
+    bool
+    operator==(
+        const shuffle_order_engine<_Eng, _Kp>& __x,
+        const shuffle_order_engine<_Eng, _Kp>& __y);
+
+    template<class _Eng, size_t _Kp>
+    friend
+    bool
+    operator!=(
+        const shuffle_order_engine<_Eng, _Kp>& __x,
+        const shuffle_order_engine<_Eng, _Kp>& __y);
+
+    template <class _CharT, class _Traits,
+              class _Eng, size_t _Kp>
+    friend
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+               const shuffle_order_engine<_Eng, _Kp>& __x);
+
+    template <class _CharT, class _Traits,
+              class _Eng, size_t _Kp>
+    friend
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is,
+               shuffle_order_engine<_Eng, _Kp>& __x);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __init()
+    {
+        for (size_t __i = 0; __i < __k; ++__i)
+            _V_[__i] = __e_();
+        _Y_ = __e_();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type __eval(false_type) {return __eval2(integral_constant<bool, __k & 1>());}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type __eval(true_type) {return __eval(__uratio<__k, _Rp>());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type __eval2(false_type) {return __eval(__uratio<__k/2, 0x8000000000000000ull>());}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type __eval2(true_type) {return __evalf<__k, 0>();}
+
+    template <uint64_t _Np, uint64_t _Dp>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            (__uratio<_Np, _Dp>::num > 0xFFFFFFFFFFFFFFFFull / (_Max - _Min)),
+            result_type
+        >::type
+        __eval(__uratio<_Np, _Dp>)
+            {return __evalf<__uratio<_Np, _Dp>::num, __uratio<_Np, _Dp>::den>();}
+
+    template <uint64_t _Np, uint64_t _Dp>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            __uratio<_Np, _Dp>::num <= 0xFFFFFFFFFFFFFFFFull / (_Max - _Min),
+            result_type
+        >::type
+        __eval(__uratio<_Np, _Dp>)
+        {
+            const size_t __j = static_cast<size_t>(__uratio<_Np, _Dp>::num * (_Y_ - _Min)
+                                                   / __uratio<_Np, _Dp>::den);
+            _Y_ = _V_[__j];
+            _V_[__j] = __e_();
+            return _Y_;
+        }
+
+    template <uint64_t __n, uint64_t __d>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type __evalf()
+        {
+            const double _Fp = __d == 0 ?
+                __n / (2. * 0x8000000000000000ull) :
+                __n / (double)__d;
+            const size_t __j = static_cast<size_t>(_Fp * (_Y_ - _Min));
+            _Y_ = _V_[__j];
+            _V_[__j] = __e_();
+            return _Y_;
+        }
+};
+
+template<class _Engine, size_t __k>
+    _LIBCPP_CONSTEXPR const size_t shuffle_order_engine<_Engine, __k>::table_size;
+
+template<class _Eng, size_t _Kp>
+bool
+operator==(
+    const shuffle_order_engine<_Eng, _Kp>& __x,
+    const shuffle_order_engine<_Eng, _Kp>& __y)
+{
+    return __x._Y_ == __y._Y_ && _VSTD::equal(__x._V_, __x._V_ + _Kp, __y._V_) &&
+           __x.__e_ == __y.__e_;
+}
+
+template<class _Eng, size_t _Kp>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(
+    const shuffle_order_engine<_Eng, _Kp>& __x,
+    const shuffle_order_engine<_Eng, _Kp>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _CharT, class _Traits,
+          class _Eng, size_t _Kp>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const shuffle_order_engine<_Eng, _Kp>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _Ostream;
+    __os.flags(_Ostream::dec | _Ostream::left);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    __os << __x.__e_ << __sp << __x._V_[0];
+    for (size_t __i = 1; __i < _Kp; ++__i)
+        __os << __sp << __x._V_[__i];
+    return __os << __sp << __x._Y_;
+}
+
+template <class _CharT, class _Traits,
+          class _Eng, size_t _Kp>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           shuffle_order_engine<_Eng, _Kp>& __x)
+{
+    typedef typename shuffle_order_engine<_Eng, _Kp>::result_type result_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    _Eng __e;
+    result_type _Vp[_Kp+1];
+    __is >> __e;
+    for (size_t __i = 0; __i < _Kp+1; ++__i)
+        __is >> _Vp[__i];
+    if (!__is.fail())
+    {
+        __x.__e_ = __e;
+        for (size_t __i = 0; __i < _Kp; ++__i)
+            __x._V_[__i] = _Vp[__i];
+        __x._Y_ = _Vp[_Kp];
+    }
+    return __is;
+}
+
+typedef shuffle_order_engine<minstd_rand0, 256>                         knuth_b;
+
+// random_device
+
+#if !defined(_LIBCPP_HAS_NO_RANDOM_DEVICE)
+
+class _LIBCPP_TYPE_VIS random_device
+{
+#ifdef _LIBCPP_USING_DEV_RANDOM
+    int __f_;
+#endif // defined(_LIBCPP_USING_DEV_RANDOM)
+public:
+    // types
+    typedef unsigned result_type;
+
+    // generator characteristics
+    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
+    static _LIBCPP_CONSTEXPR const result_type _Max = 0xFFFFFFFFu;
+
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type min() { return _Min;}
+    _LIBCPP_INLINE_VISIBILITY
+    static _LIBCPP_CONSTEXPR result_type max() { return _Max;}
+
+    // constructors
+#ifndef _LIBCPP_CXX03_LANG
+    random_device() : random_device("/dev/urandom") {}
+    explicit random_device(const string& __token);
+#else
+    explicit random_device(const string& __token = "/dev/urandom");
+#endif
+    ~random_device();
+
+    // generating functions
+    result_type operator()();
+
+    // property functions
+    double entropy() const _NOEXCEPT;
+
+private:
+    // no copy functions
+    random_device(const random_device&); // = delete;
+    random_device& operator=(const random_device&); // = delete;
+};
+
+#endif // !_LIBCPP_HAS_NO_RANDOM_DEVICE
+
+// seed_seq
+
+class _LIBCPP_TEMPLATE_VIS seed_seq
+{
+public:
+    // types
+    typedef uint32_t result_type;
+
+private:
+    vector<result_type> __v_;
+
+    template<class _InputIterator>
+        void init(_InputIterator __first, _InputIterator __last);
+public:
+    // constructors
+    _LIBCPP_INLINE_VISIBILITY
+    seed_seq() _NOEXCEPT {}
+#ifndef _LIBCPP_CXX03_LANG
+    template<class _Tp>
+        _LIBCPP_INLINE_VISIBILITY
+        seed_seq(initializer_list<_Tp> __il) {init(__il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+
+    template<class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        seed_seq(_InputIterator __first, _InputIterator __last)
+             {init(__first, __last);}
+
+    // generating functions
+    template<class _RandomAccessIterator>
+        void generate(_RandomAccessIterator __first, _RandomAccessIterator __last);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const _NOEXCEPT {return __v_.size();}
+    template<class _OutputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        void param(_OutputIterator __dest) const
+            {_VSTD::copy(__v_.begin(), __v_.end(), __dest);}
+
+private:
+    // no copy functions
+    seed_seq(const seed_seq&); // = delete;
+    void operator=(const seed_seq&); // = delete;
+
+    _LIBCPP_INLINE_VISIBILITY
+    static result_type _Tp(result_type __x) {return __x ^ (__x >> 27);}
+};
+
+template<class _InputIterator>
+void
+seed_seq::init(_InputIterator __first, _InputIterator __last)
+{
+    for (_InputIterator __s = __first; __s != __last; ++__s)
+        __v_.push_back(*__s & 0xFFFFFFFF);
+}
+
+template<class _RandomAccessIterator>
+void
+seed_seq::generate(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    if (__first != __last)
+    {
+        _VSTD::fill(__first, __last, 0x8b8b8b8b);
+        const size_t __n = static_cast<size_t>(__last - __first);
+        const size_t __s = __v_.size();
+        const size_t __t = (__n >= 623) ? 11
+                         : (__n >= 68) ? 7
+                         : (__n >= 39) ? 5
+                         : (__n >= 7)  ? 3
+                         : (__n - 1) / 2;
+        const size_t __p = (__n - __t) / 2;
+        const size_t __q = __p + __t;
+        const size_t __m = _VSTD::max(__s + 1, __n);
+        // __k = 0;
+        {
+            result_type __r = 1664525 * _Tp(__first[0] ^ __first[__p]
+                                                      ^  __first[__n - 1]);
+            __first[__p] += __r;
+            __r += __s;
+            __first[__q] += __r;
+            __first[0] = __r;
+        }
+        for (size_t __k = 1; __k <= __s; ++__k)
+        {
+            const size_t __kmodn = __k % __n;
+            const size_t __kpmodn = (__k + __p) % __n;
+            result_type __r = 1664525 * _Tp(__first[__kmodn] ^ __first[__kpmodn]
+                                           ^ __first[(__k - 1) % __n]);
+            __first[__kpmodn] += __r;
+            __r +=  __kmodn + __v_[__k-1];
+            __first[(__k + __q) % __n] += __r;
+            __first[__kmodn] = __r;
+        }
+        for (size_t __k = __s + 1; __k < __m; ++__k)
+        {
+            const size_t __kmodn = __k % __n;
+            const size_t __kpmodn = (__k + __p) % __n;
+            result_type __r = 1664525 * _Tp(__first[__kmodn] ^ __first[__kpmodn]
+                                           ^ __first[(__k - 1) % __n]);
+            __first[__kpmodn] += __r;
+            __r +=  __kmodn;
+            __first[(__k + __q) % __n] += __r;
+            __first[__kmodn] = __r;
+        }
+        for (size_t __k = __m; __k < __m + __n; ++__k)
+        {
+            const size_t __kmodn = __k % __n;
+            const size_t __kpmodn = (__k + __p) % __n;
+            result_type __r = 1566083941 * _Tp(__first[__kmodn] +
+                                              __first[__kpmodn] +
+                                              __first[(__k - 1) % __n]);
+            __first[__kpmodn] ^= __r;
+            __r -= __kmodn;
+            __first[(__k + __q) % __n] ^= __r;
+            __first[__kmodn] = __r;
+        }
+    }
+}
+
+// generate_canonical
+
+template<class _RealType, size_t __bits, class _URNG>
+_RealType
+generate_canonical(_URNG& __g)
+{
+    const size_t _Dt = numeric_limits<_RealType>::digits;
+    const size_t __b = _Dt < __bits ? _Dt : __bits;
+#ifdef _LIBCPP_CXX03_LANG
+    const size_t __logR = __log2<uint64_t, _URNG::_Max - _URNG::_Min + uint64_t(1)>::value;
+#else
+    const size_t __logR = __log2<uint64_t, _URNG::max() - _URNG::min() + uint64_t(1)>::value;
+#endif
+    const size_t __k = __b / __logR + (__b % __logR != 0) + (__b == 0);
+    const _RealType _Rp = static_cast<_RealType>(_URNG::max() - _URNG::min()) + _RealType(1);
+    _RealType __base = _Rp;
+    _RealType _Sp = __g() - _URNG::min();
+    for (size_t __i = 1; __i < __k; ++__i, __base *= _Rp)
+        _Sp += (__g() - _URNG::min()) * __base;
+    return _Sp / __base;
+}
+
+// uniform_real_distribution
+
+template<class _RealType = double>
+class _LIBCPP_TEMPLATE_VIS uniform_real_distribution
+{
+public:
+    // types
+    typedef _RealType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        result_type __a_;
+        result_type __b_;
+    public:
+        typedef uniform_real_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(result_type __a = 0,
+                            result_type __b = 1)
+            : __a_(__a), __b_(__b) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        result_type a() const {return __a_;}
+        _LIBCPP_INLINE_VISIBILITY
+        result_type b() const {return __b_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructors and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    uniform_real_distribution() : uniform_real_distribution(0) {}
+    explicit uniform_real_distribution(result_type __a, result_type __b = 1)
+        : __p_(param_type(__a, __b)) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit uniform_real_distribution(result_type __a = 0, result_type __b = 1)
+        : __p_(param_type(__a, __b)) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit uniform_real_distribution(const param_type& __p) : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> _LIBCPP_INLINE_VISIBILITY result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type a() const {return __p_.a();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type b() const {return __p_.b();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return a();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return b();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const uniform_real_distribution& __x,
+                        const uniform_real_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const uniform_real_distribution& __x,
+                        const uniform_real_distribution& __y)
+        {return !(__x == __y);}
+};
+
+template<class _RealType>
+template<class _URNG>
+inline
+typename uniform_real_distribution<_RealType>::result_type
+uniform_real_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
+{
+    return (__p.b() - __p.a())
+        * _VSTD::generate_canonical<_RealType, numeric_limits<_RealType>::digits>(__g)
+        + __p.a();
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const uniform_real_distribution<_RT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    return __os << __x.a() << __sp << __x.b();
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           uniform_real_distribution<_RT>& __x)
+{
+    typedef uniform_real_distribution<_RT> _Eng;
+    typedef typename _Eng::result_type result_type;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    result_type __a;
+    result_type __b;
+    __is >> __a >> __b;
+    if (!__is.fail())
+        __x.param(param_type(__a, __b));
+    return __is;
+}
+
+// bernoulli_distribution
+
+class _LIBCPP_TEMPLATE_VIS bernoulli_distribution
+{
+public:
+    // types
+    typedef bool result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        double __p_;
+    public:
+        typedef bernoulli_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(double __p = 0.5) : __p_(__p) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        double p() const {return __p_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__p_ == __y.__p_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructors and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    bernoulli_distribution() : bernoulli_distribution(0.5) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit bernoulli_distribution(double __p) : __p_(param_type(__p)) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit bernoulli_distribution(double __p = 0.5) : __p_(param_type(__p)) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit bernoulli_distribution(const param_type& __p) : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> _LIBCPP_INLINE_VISIBILITY result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    double p() const {return __p_.p();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return false;}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return true;}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const bernoulli_distribution& __x,
+                        const bernoulli_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const bernoulli_distribution& __x,
+                        const bernoulli_distribution& __y)
+        {return !(__x == __y);}
+};
+
+template<class _URNG>
+inline
+bernoulli_distribution::result_type
+bernoulli_distribution::operator()(_URNG& __g, const param_type& __p)
+{
+    uniform_real_distribution<double> __gen;
+    return __gen(__g) < __p.p();
+}
+
+template <class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const bernoulli_distribution& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    return __os << __x.p();
+}
+
+template <class _CharT, class _Traits>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, bernoulli_distribution& __x)
+{
+    typedef bernoulli_distribution _Eng;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    double __p;
+    __is >> __p;
+    if (!__is.fail())
+        __x.param(param_type(__p));
+    return __is;
+}
+
+// binomial_distribution
+
+template<class _IntType = int>
+class _LIBCPP_TEMPLATE_VIS binomial_distribution
+{
+public:
+    // types
+    typedef _IntType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        result_type __t_;
+        double __p_;
+        double __pr_;
+        double __odds_ratio_;
+        result_type __r0_;
+    public:
+        typedef binomial_distribution distribution_type;
+
+        explicit param_type(result_type __t = 1, double __p = 0.5);
+
+        _LIBCPP_INLINE_VISIBILITY
+        result_type t() const {return __t_;}
+        _LIBCPP_INLINE_VISIBILITY
+        double p() const {return __p_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__t_ == __y.__t_ && __x.__p_ == __y.__p_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+
+        friend class binomial_distribution;
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructors and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    binomial_distribution() : binomial_distribution(1) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit binomial_distribution(result_type __t, double __p = 0.5)
+        : __p_(param_type(__t, __p)) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit binomial_distribution(result_type __t = 1, double __p = 0.5)
+        : __p_(param_type(__t, __p)) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit binomial_distribution(const param_type& __p) : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type t() const {return __p_.t();}
+    _LIBCPP_INLINE_VISIBILITY
+    double p() const {return __p_.p();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return t();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const binomial_distribution& __x,
+                        const binomial_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const binomial_distribution& __x,
+                        const binomial_distribution& __y)
+        {return !(__x == __y);}
+};
+
+#ifndef _LIBCPP_MSVCRT_LIKE
+extern "C" double lgamma_r(double, int *);
+#endif
+
+inline _LIBCPP_INLINE_VISIBILITY double __libcpp_lgamma(double __d) {
+#if defined(_LIBCPP_MSVCRT_LIKE)
+  return lgamma(__d);
+#else
+  int __sign;
+  return lgamma_r(__d, &__sign);
+#endif
+}
+
+template<class _IntType>
+binomial_distribution<_IntType>::param_type::param_type(result_type __t, double __p)
+    : __t_(__t), __p_(__p)
+{
+    if (0 < __p_ && __p_ < 1)
+    {
+        __r0_ = static_cast<result_type>((__t_ + 1) * __p_);
+        __pr_ = _VSTD::exp(__libcpp_lgamma(__t_ + 1.) -
+                           __libcpp_lgamma(__r0_ + 1.) -
+                           __libcpp_lgamma(__t_ - __r0_ + 1.) + __r0_ * _VSTD::log(__p_) +
+                           (__t_ - __r0_) * _VSTD::log(1 - __p_));
+        __odds_ratio_ = __p_ / (1 - __p_);
+    }
+}
+
+// Reference: Kemp, C.D. (1986). `A modal method for generating binomial
+//           variables', Commun. Statist. - Theor. Meth. 15(3), 805-813.
+template<class _IntType>
+template<class _URNG>
+_IntType
+binomial_distribution<_IntType>::operator()(_URNG& __g, const param_type& __pr)
+{
+    if (__pr.__t_ == 0 || __pr.__p_ == 0)
+        return 0;
+    if (__pr.__p_ == 1)
+        return __pr.__t_;
+    uniform_real_distribution<double> __gen;
+    double __u = __gen(__g) - __pr.__pr_;
+    if (__u < 0)
+        return __pr.__r0_;
+    double __pu = __pr.__pr_;
+    double __pd = __pu;
+    result_type __ru = __pr.__r0_;
+    result_type __rd = __ru;
+    while (true)
+    {
+        bool __break = true;
+        if (__rd >= 1)
+        {
+            __pd *= __rd / (__pr.__odds_ratio_ * (__pr.__t_ - __rd + 1));
+            __u -= __pd;
+            __break = false;
+            if (__u < 0)
+                return __rd - 1;
+        }
+        if ( __rd != 0 )
+            --__rd;
+        ++__ru;
+        if (__ru <= __pr.__t_)
+        {
+            __pu *= (__pr.__t_ - __ru + 1) * __pr.__odds_ratio_ / __ru;
+            __u -= __pu;
+            __break = false;
+            if (__u < 0)
+                return __ru;
+        }
+        if (__break)
+            return 0;
+    }
+}
+
+template <class _CharT, class _Traits, class _IntType>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const binomial_distribution<_IntType>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    return __os << __x.t() << __sp << __x.p();
+}
+
+template <class _CharT, class _Traits, class _IntType>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           binomial_distribution<_IntType>& __x)
+{
+    typedef binomial_distribution<_IntType> _Eng;
+    typedef typename _Eng::result_type result_type;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    result_type __t;
+    double __p;
+    __is >> __t >> __p;
+    if (!__is.fail())
+        __x.param(param_type(__t, __p));
+    return __is;
+}
+
+// exponential_distribution
+
+template<class _RealType = double>
+class _LIBCPP_TEMPLATE_VIS exponential_distribution
+{
+public:
+    // types
+    typedef _RealType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        result_type __lambda_;
+    public:
+        typedef exponential_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(result_type __lambda = 1) : __lambda_(__lambda) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        result_type lambda() const {return __lambda_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__lambda_ == __y.__lambda_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructors and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    exponential_distribution() : exponential_distribution(1) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit exponential_distribution(result_type __lambda)
+        : __p_(param_type(__lambda)) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit exponential_distribution(result_type __lambda = 1)
+        : __p_(param_type(__lambda)) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit exponential_distribution(const param_type& __p) : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type lambda() const {return __p_.lambda();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return numeric_limits<result_type>::infinity();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const exponential_distribution& __x,
+                        const exponential_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const exponential_distribution& __x,
+                        const exponential_distribution& __y)
+        {return !(__x == __y);}
+};
+
+template <class _RealType>
+template<class _URNG>
+_RealType
+exponential_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
+{
+    return -_VSTD::log
+                  (
+                      result_type(1) -
+                      _VSTD::generate_canonical<result_type,
+                                       numeric_limits<result_type>::digits>(__g)
+                  )
+                  / __p.lambda();
+}
+
+template <class _CharT, class _Traits, class _RealType>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const exponential_distribution<_RealType>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    return __os << __x.lambda();
+}
+
+template <class _CharT, class _Traits, class _RealType>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           exponential_distribution<_RealType>& __x)
+{
+    typedef exponential_distribution<_RealType> _Eng;
+    typedef typename _Eng::result_type result_type;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    result_type __lambda;
+    __is >> __lambda;
+    if (!__is.fail())
+        __x.param(param_type(__lambda));
+    return __is;
+}
+
+// normal_distribution
+
+template<class _RealType = double>
+class _LIBCPP_TEMPLATE_VIS normal_distribution
+{
+public:
+    // types
+    typedef _RealType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        result_type __mean_;
+        result_type __stddev_;
+    public:
+        typedef normal_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(result_type __mean = 0, result_type __stddev = 1)
+            : __mean_(__mean), __stddev_(__stddev) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        result_type mean() const {return __mean_;}
+        _LIBCPP_INLINE_VISIBILITY
+        result_type stddev() const {return __stddev_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__mean_ == __y.__mean_ && __x.__stddev_ == __y.__stddev_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+    result_type _V_;
+    bool _V_hot_;
+
+public:
+    // constructors and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    normal_distribution() : normal_distribution(0) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit normal_distribution(result_type __mean, result_type __stddev = 1)
+        : __p_(param_type(__mean, __stddev)), _V_hot_(false) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit normal_distribution(result_type __mean = 0,
+                                 result_type __stddev = 1)
+        : __p_(param_type(__mean, __stddev)), _V_hot_(false) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit normal_distribution(const param_type& __p)
+        : __p_(__p), _V_hot_(false) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {_V_hot_ = false;}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type mean() const {return __p_.mean();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type stddev() const {return __p_.stddev();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return -numeric_limits<result_type>::infinity();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return numeric_limits<result_type>::infinity();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const normal_distribution& __x,
+                        const normal_distribution& __y)
+        {return __x.__p_ == __y.__p_ && __x._V_hot_ == __y._V_hot_ &&
+                (!__x._V_hot_ || __x._V_ == __y._V_);}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const normal_distribution& __x,
+                        const normal_distribution& __y)
+        {return !(__x == __y);}
+
+    template <class _CharT, class _Traits, class _RT>
+    friend
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+               const normal_distribution<_RT>& __x);
+
+    template <class _CharT, class _Traits, class _RT>
+    friend
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is,
+               normal_distribution<_RT>& __x);
+};
+
+template <class _RealType>
+template<class _URNG>
+_RealType
+normal_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
+{
+    result_type _Up;
+    if (_V_hot_)
+    {
+        _V_hot_ = false;
+        _Up = _V_;
+    }
+    else
+    {
+        uniform_real_distribution<result_type> _Uni(-1, 1);
+        result_type __u;
+        result_type __v;
+        result_type __s;
+        do
+        {
+            __u = _Uni(__g);
+            __v = _Uni(__g);
+            __s = __u * __u + __v * __v;
+        } while (__s > 1 || __s == 0);
+        result_type _Fp = _VSTD::sqrt(-2 * _VSTD::log(__s) / __s);
+        _V_ = __v * _Fp;
+        _V_hot_ = true;
+        _Up = __u * _Fp;
+    }
+    return _Up * __p.stddev() + __p.mean();
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const normal_distribution<_RT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    __os << __x.mean() << __sp << __x.stddev() << __sp << __x._V_hot_;
+    if (__x._V_hot_)
+        __os << __sp << __x._V_;
+    return __os;
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           normal_distribution<_RT>& __x)
+{
+    typedef normal_distribution<_RT> _Eng;
+    typedef typename _Eng::result_type result_type;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    result_type __mean;
+    result_type __stddev;
+    result_type _Vp = 0;
+    bool _V_hot = false;
+    __is >> __mean >> __stddev >> _V_hot;
+    if (_V_hot)
+        __is >> _Vp;
+    if (!__is.fail())
+    {
+        __x.param(param_type(__mean, __stddev));
+        __x._V_hot_ = _V_hot;
+        __x._V_ = _Vp;
+    }
+    return __is;
+}
+
+// lognormal_distribution
+
+template<class _RealType = double>
+class _LIBCPP_TEMPLATE_VIS lognormal_distribution
+{
+public:
+    // types
+    typedef _RealType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        normal_distribution<result_type> __nd_;
+    public:
+        typedef lognormal_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(result_type __m = 0, result_type __s = 1)
+            : __nd_(__m, __s) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        result_type m() const {return __nd_.mean();}
+        _LIBCPP_INLINE_VISIBILITY
+        result_type s() const {return __nd_.stddev();}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__nd_ == __y.__nd_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+        friend class lognormal_distribution;
+
+        template <class _CharT, class _Traits, class _RT>
+        friend
+        basic_ostream<_CharT, _Traits>&
+        operator<<(basic_ostream<_CharT, _Traits>& __os,
+                   const lognormal_distribution<_RT>& __x);
+
+        template <class _CharT, class _Traits, class _RT>
+        friend
+        basic_istream<_CharT, _Traits>&
+        operator>>(basic_istream<_CharT, _Traits>& __is,
+                   lognormal_distribution<_RT>& __x);
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructor and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    lognormal_distribution() : lognormal_distribution(0) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit lognormal_distribution(result_type __m, result_type __s = 1)
+        : __p_(param_type(__m, __s)) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit lognormal_distribution(result_type __m = 0,
+                                    result_type __s = 1)
+        : __p_(param_type(__m, __s)) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit lognormal_distribution(const param_type& __p)
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {__p_.__nd_.reset();}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g, const param_type& __p)
+        {return _VSTD::exp(const_cast<normal_distribution<result_type>&>(__p.__nd_)(__g));}
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type m() const {return __p_.m();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type s() const {return __p_.s();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return numeric_limits<result_type>::infinity();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const lognormal_distribution& __x,
+                        const lognormal_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const lognormal_distribution& __x,
+                        const lognormal_distribution& __y)
+        {return !(__x == __y);}
+
+    template <class _CharT, class _Traits, class _RT>
+    friend
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+               const lognormal_distribution<_RT>& __x);
+
+    template <class _CharT, class _Traits, class _RT>
+    friend
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is,
+               lognormal_distribution<_RT>& __x);
+};
+
+template <class _CharT, class _Traits, class _RT>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const lognormal_distribution<_RT>& __x)
+{
+    return __os << __x.__p_.__nd_;
+}
+
+template <class _CharT, class _Traits, class _RT>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           lognormal_distribution<_RT>& __x)
+{
+    return __is >> __x.__p_.__nd_;
+}
+
+// poisson_distribution
+
+template<class _IntType = int>
+class _LIBCPP_TEMPLATE_VIS poisson_distribution
+{
+public:
+    // types
+    typedef _IntType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        double __mean_;
+        double __s_;
+        double __d_;
+        double __l_;
+        double __omega_;
+        double __c0_;
+        double __c1_;
+        double __c2_;
+        double __c3_;
+        double __c_;
+
+    public:
+        typedef poisson_distribution distribution_type;
+
+        explicit param_type(double __mean = 1.0);
+
+        _LIBCPP_INLINE_VISIBILITY
+        double mean() const {return __mean_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__mean_ == __y.__mean_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+
+        friend class poisson_distribution;
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructors and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    poisson_distribution() : poisson_distribution(1.0) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit poisson_distribution(double __mean)
+        : __p_(__mean) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit poisson_distribution(double __mean = 1.0)
+        : __p_(__mean) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit poisson_distribution(const param_type& __p) : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    double mean() const {return __p_.mean();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return numeric_limits<result_type>::max();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const poisson_distribution& __x,
+                        const poisson_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const poisson_distribution& __x,
+                        const poisson_distribution& __y)
+        {return !(__x == __y);}
+};
+
+template<class _IntType>
+poisson_distribution<_IntType>::param_type::param_type(double __mean)
+    // According to the standard `inf` is a valid input, but it causes the
+    // distribution to hang, so we replace it with the maximum representable
+    // mean.
+    : __mean_(isinf(__mean) ? numeric_limits<double>::max() : __mean)
+{
+    if (__mean_ < 10)
+    {
+        __s_ = 0;
+        __d_ = 0;
+        __l_ = _VSTD::exp(-__mean_);
+        __omega_ = 0;
+        __c3_ = 0;
+        __c2_ = 0;
+        __c1_ = 0;
+        __c0_ = 0;
+        __c_ = 0;
+    }
+    else
+    {
+        __s_ = _VSTD::sqrt(__mean_);
+        __d_ = 6 * __mean_ * __mean_;
+        __l_ = _VSTD::trunc(__mean_ - 1.1484);
+        __omega_ = .3989423 / __s_;
+        double __b1_ = .4166667E-1 / __mean_;
+        double __b2_ = .3 * __b1_ * __b1_;
+        __c3_ = .1428571 * __b1_ * __b2_;
+        __c2_ = __b2_ - 15. * __c3_;
+        __c1_ = __b1_ - 6. * __b2_ + 45. * __c3_;
+        __c0_ = 1. - __b1_ + 3. * __b2_ - 15. * __c3_;
+        __c_ = .1069 / __mean_;
+    }
+}
+
+template <class _IntType>
+template<class _URNG>
+_IntType
+poisson_distribution<_IntType>::operator()(_URNG& __urng, const param_type& __pr)
+{
+    double __tx;
+    uniform_real_distribution<double> __urd;
+    if (__pr.__mean_ < 10)
+    {
+         __tx = 0;
+        for (double __p = __urd(__urng); __p > __pr.__l_; ++__tx)
+            __p *= __urd(__urng);
+    }
+    else
+    {
+        double __difmuk;
+        double __g = __pr.__mean_ + __pr.__s_ * normal_distribution<double>()(__urng);
+        double __u;
+        if (__g > 0)
+        {
+            __tx = _VSTD::trunc(__g);
+            if (__tx >= __pr.__l_)
+                return _VSTD::__clamp_to_integral<result_type>(__tx);
+            __difmuk = __pr.__mean_ - __tx;
+            __u = __urd(__urng);
+            if (__pr.__d_ * __u >= __difmuk * __difmuk * __difmuk)
+                return _VSTD::__clamp_to_integral<result_type>(__tx);
+        }
+        exponential_distribution<double> __edist;
+        for (bool __using_exp_dist = false; true; __using_exp_dist = true)
+        {
+            double __e;
+            if (__using_exp_dist || __g <= 0)
+            {
+                double __t;
+                do
+                {
+                    __e = __edist(__urng);
+                    __u = __urd(__urng);
+                    __u += __u - 1;
+                    __t = 1.8 + (__u < 0 ? -__e : __e);
+                } while (__t <= -.6744);
+                __tx = _VSTD::trunc(__pr.__mean_ + __pr.__s_ * __t);
+                __difmuk = __pr.__mean_ - __tx;
+                __using_exp_dist = true;
+            }
+            double __px;
+            double __py;
+            if (__tx < 10 && __tx >= 0)
+            {
+                const double __fac[] = {1, 1, 2, 6, 24, 120, 720, 5040,
+                                             40320, 362880};
+                __px = -__pr.__mean_;
+                __py = _VSTD::pow(__pr.__mean_, (double)__tx) / __fac[static_cast<int>(__tx)];
+            }
+            else
+            {
+                double __del = .8333333E-1 / __tx;
+                __del -= 4.8 * __del * __del * __del;
+                double __v = __difmuk / __tx;
+                if (_VSTD::abs(__v) > 0.25)
+                    __px = __tx * _VSTD::log(1 + __v) - __difmuk - __del;
+                else
+                    __px = __tx * __v * __v * (((((((.1250060 * __v + -.1384794) *
+                           __v + .1421878) * __v + -.1661269) * __v + .2000118) *
+                           __v + -.2500068) * __v + .3333333) * __v + -.5) - __del;
+                __py = .3989423 / _VSTD::sqrt(__tx);
+            }
+            double __r = (0.5 - __difmuk) / __pr.__s_;
+            double __r2 = __r * __r;
+            double __fx = -0.5 * __r2;
+            double __fy = __pr.__omega_ * (((__pr.__c3_ * __r2 + __pr.__c2_) *
+                                        __r2 + __pr.__c1_) * __r2 + __pr.__c0_);
+            if (__using_exp_dist)
+            {
+                if (__pr.__c_ * _VSTD::abs(__u) <= __py * _VSTD::exp(__px + __e) -
+                                                   __fy * _VSTD::exp(__fx + __e))
+                    break;
+            }
+            else
+            {
+                if (__fy - __u * __fy <= __py * _VSTD::exp(__px - __fx))
+                    break;
+            }
+        }
+    }
+    return _VSTD::__clamp_to_integral<result_type>(__tx);
+}
+
+template <class _CharT, class _Traits, class _IntType>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const poisson_distribution<_IntType>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    return __os << __x.mean();
+}
+
+template <class _CharT, class _Traits, class _IntType>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           poisson_distribution<_IntType>& __x)
+{
+    typedef poisson_distribution<_IntType> _Eng;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    double __mean;
+    __is >> __mean;
+    if (!__is.fail())
+        __x.param(param_type(__mean));
+    return __is;
+}
+
+// weibull_distribution
+
+template<class _RealType = double>
+class _LIBCPP_TEMPLATE_VIS weibull_distribution
+{
+public:
+    // types
+    typedef _RealType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        result_type __a_;
+        result_type __b_;
+    public:
+        typedef weibull_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(result_type __a = 1, result_type __b = 1)
+            : __a_(__a), __b_(__b) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        result_type a() const {return __a_;}
+        _LIBCPP_INLINE_VISIBILITY
+        result_type b() const {return __b_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructor and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    weibull_distribution() : weibull_distribution(1) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit weibull_distribution(result_type __a, result_type __b = 1)
+        : __p_(param_type(__a, __b)) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit weibull_distribution(result_type __a = 1, result_type __b = 1)
+        : __p_(param_type(__a, __b)) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit weibull_distribution(const param_type& __p)
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g, const param_type& __p)
+        {return __p.b() *
+            _VSTD::pow(exponential_distribution<result_type>()(__g), 1/__p.a());}
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type a() const {return __p_.a();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type b() const {return __p_.b();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return numeric_limits<result_type>::infinity();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const weibull_distribution& __x,
+                        const weibull_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const weibull_distribution& __x,
+                        const weibull_distribution& __y)
+        {return !(__x == __y);}
+};
+
+template <class _CharT, class _Traits, class _RT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const weibull_distribution<_RT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    __os << __x.a() << __sp << __x.b();
+    return __os;
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           weibull_distribution<_RT>& __x)
+{
+    typedef weibull_distribution<_RT> _Eng;
+    typedef typename _Eng::result_type result_type;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    result_type __a;
+    result_type __b;
+    __is >> __a >> __b;
+    if (!__is.fail())
+        __x.param(param_type(__a, __b));
+    return __is;
+}
+
+template<class _RealType = double>
+class _LIBCPP_TEMPLATE_VIS extreme_value_distribution
+{
+public:
+    // types
+    typedef _RealType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        result_type __a_;
+        result_type __b_;
+    public:
+        typedef extreme_value_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(result_type __a = 0, result_type __b = 1)
+            : __a_(__a), __b_(__b) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        result_type a() const {return __a_;}
+        _LIBCPP_INLINE_VISIBILITY
+        result_type b() const {return __b_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructor and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    extreme_value_distribution() : extreme_value_distribution(0) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit extreme_value_distribution(result_type __a, result_type __b = 1)
+        : __p_(param_type(__a, __b)) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit extreme_value_distribution(result_type __a = 0,
+                                        result_type __b = 1)
+        : __p_(param_type(__a, __b)) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit extreme_value_distribution(const param_type& __p)
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type a() const {return __p_.a();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type b() const {return __p_.b();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return -numeric_limits<result_type>::infinity();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return numeric_limits<result_type>::infinity();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const extreme_value_distribution& __x,
+                        const extreme_value_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const extreme_value_distribution& __x,
+                        const extreme_value_distribution& __y)
+        {return !(__x == __y);}
+};
+
+template<class _RealType>
+template<class _URNG>
+_RealType
+extreme_value_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
+{
+    return __p.a() - __p.b() *
+         _VSTD::log(-_VSTD::log(1-uniform_real_distribution<result_type>()(__g)));
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const extreme_value_distribution<_RT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    __os << __x.a() << __sp << __x.b();
+    return __os;
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           extreme_value_distribution<_RT>& __x)
+{
+    typedef extreme_value_distribution<_RT> _Eng;
+    typedef typename _Eng::result_type result_type;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    result_type __a;
+    result_type __b;
+    __is >> __a >> __b;
+    if (!__is.fail())
+        __x.param(param_type(__a, __b));
+    return __is;
+}
+
+// gamma_distribution
+
+template<class _RealType = double>
+class _LIBCPP_TEMPLATE_VIS gamma_distribution
+{
+public:
+    // types
+    typedef _RealType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        result_type __alpha_;
+        result_type __beta_;
+    public:
+        typedef gamma_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(result_type __alpha = 1, result_type __beta = 1)
+            : __alpha_(__alpha), __beta_(__beta) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        result_type alpha() const {return __alpha_;}
+        _LIBCPP_INLINE_VISIBILITY
+        result_type beta() const {return __beta_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__alpha_ == __y.__alpha_ && __x.__beta_ == __y.__beta_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructors and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    gamma_distribution() : gamma_distribution(1) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit gamma_distribution(result_type __alpha, result_type __beta = 1)
+        : __p_(param_type(__alpha, __beta)) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit gamma_distribution(result_type __alpha = 1,
+                                result_type __beta = 1)
+        : __p_(param_type(__alpha, __beta)) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit gamma_distribution(const param_type& __p)
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type alpha() const {return __p_.alpha();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type beta() const {return __p_.beta();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return numeric_limits<result_type>::infinity();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const gamma_distribution& __x,
+                        const gamma_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const gamma_distribution& __x,
+                        const gamma_distribution& __y)
+        {return !(__x == __y);}
+};
+
+template <class _RealType>
+template<class _URNG>
+_RealType
+gamma_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
+{
+    result_type __a = __p.alpha();
+    uniform_real_distribution<result_type> __gen(0, 1);
+    exponential_distribution<result_type> __egen;
+    result_type __x;
+    if (__a == 1)
+        __x = __egen(__g);
+    else if (__a > 1)
+    {
+        const result_type __b = __a - 1;
+        const result_type __c = 3 * __a - result_type(0.75);
+        while (true)
+        {
+            const result_type __u = __gen(__g);
+            const result_type __v = __gen(__g);
+            const result_type __w = __u * (1 - __u);
+            if (__w != 0)
+            {
+                const result_type __y = _VSTD::sqrt(__c / __w) *
+                                        (__u - result_type(0.5));
+                __x = __b + __y;
+                if (__x >= 0)
+                {
+                    const result_type __z = 64 * __w * __w * __w * __v * __v;
+                    if (__z <= 1 - 2 * __y * __y / __x)
+                        break;
+                    if (_VSTD::log(__z) <= 2 * (__b * _VSTD::log(__x / __b) - __y))
+                        break;
+                }
+            }
+        }
+    }
+    else  // __a < 1
+    {
+        while (true)
+        {
+            const result_type __u = __gen(__g);
+            const result_type __es = __egen(__g);
+            if (__u <= 1 - __a)
+            {
+                __x = _VSTD::pow(__u, 1 / __a);
+                if (__x <= __es)
+                    break;
+            }
+            else
+            {
+                const result_type __e = -_VSTD::log((1-__u)/__a);
+                __x = _VSTD::pow(1 - __a + __a * __e, 1 / __a);
+                if (__x <= __e + __es)
+                    break;
+            }
+        }
+    }
+    return __x * __p.beta();
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const gamma_distribution<_RT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    __os << __x.alpha() << __sp << __x.beta();
+    return __os;
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           gamma_distribution<_RT>& __x)
+{
+    typedef gamma_distribution<_RT> _Eng;
+    typedef typename _Eng::result_type result_type;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    result_type __alpha;
+    result_type __beta;
+    __is >> __alpha >> __beta;
+    if (!__is.fail())
+        __x.param(param_type(__alpha, __beta));
+    return __is;
+}
+
+// negative_binomial_distribution
+
+template<class _IntType = int>
+class _LIBCPP_TEMPLATE_VIS negative_binomial_distribution
+{
+public:
+    // types
+    typedef _IntType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        result_type __k_;
+        double __p_;
+    public:
+        typedef negative_binomial_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(result_type __k = 1, double __p = 0.5)
+            : __k_(__k), __p_(__p) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        result_type k() const {return __k_;}
+        _LIBCPP_INLINE_VISIBILITY
+        double p() const {return __p_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__k_ == __y.__k_ && __x.__p_ == __y.__p_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructor and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    negative_binomial_distribution() : negative_binomial_distribution(1) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit negative_binomial_distribution(result_type __k, double __p = 0.5)
+        : __p_(__k, __p) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit negative_binomial_distribution(result_type __k = 1,
+                                            double __p = 0.5)
+        : __p_(__k, __p) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit negative_binomial_distribution(const param_type& __p) : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type k() const {return __p_.k();}
+    _LIBCPP_INLINE_VISIBILITY
+    double p() const {return __p_.p();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return numeric_limits<result_type>::max();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const negative_binomial_distribution& __x,
+                        const negative_binomial_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const negative_binomial_distribution& __x,
+                        const negative_binomial_distribution& __y)
+        {return !(__x == __y);}
+};
+
+template <class _IntType>
+template<class _URNG>
+_IntType
+negative_binomial_distribution<_IntType>::operator()(_URNG& __urng, const param_type& __pr)
+{
+    result_type __k = __pr.k();
+    double __p = __pr.p();
+    if (__k <= 21 * __p)
+    {
+        bernoulli_distribution __gen(__p);
+        result_type __f = 0;
+        result_type __s = 0;
+        while (__s < __k)
+        {
+            if (__gen(__urng))
+                ++__s;
+            else
+                ++__f;
+        }
+        return __f;
+    }
+    return poisson_distribution<result_type>(gamma_distribution<double>
+                                            (__k, (1-__p)/__p)(__urng))(__urng);
+}
+
+template <class _CharT, class _Traits, class _IntType>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const negative_binomial_distribution<_IntType>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    return __os << __x.k() << __sp << __x.p();
+}
+
+template <class _CharT, class _Traits, class _IntType>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           negative_binomial_distribution<_IntType>& __x)
+{
+    typedef negative_binomial_distribution<_IntType> _Eng;
+    typedef typename _Eng::result_type result_type;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    result_type __k;
+    double __p;
+    __is >> __k >> __p;
+    if (!__is.fail())
+        __x.param(param_type(__k, __p));
+    return __is;
+}
+
+// geometric_distribution
+
+template<class _IntType = int>
+class _LIBCPP_TEMPLATE_VIS geometric_distribution
+{
+public:
+    // types
+    typedef _IntType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        double __p_;
+    public:
+        typedef geometric_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(double __p = 0.5) : __p_(__p) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        double p() const {return __p_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__p_ == __y.__p_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructors and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    geometric_distribution() : geometric_distribution(0.5) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit geometric_distribution(double __p)
+        : __p_(__p) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit geometric_distribution(double __p = 0.5)
+        : __p_(__p) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit geometric_distribution(const param_type& __p) : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g, const param_type& __p)
+        {return negative_binomial_distribution<result_type>(1, __p.p())(__g);}
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    double p() const {return __p_.p();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return numeric_limits<result_type>::max();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const geometric_distribution& __x,
+                        const geometric_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const geometric_distribution& __x,
+                        const geometric_distribution& __y)
+        {return !(__x == __y);}
+};
+
+template <class _CharT, class _Traits, class _IntType>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const geometric_distribution<_IntType>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    return __os << __x.p();
+}
+
+template <class _CharT, class _Traits, class _IntType>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           geometric_distribution<_IntType>& __x)
+{
+    typedef geometric_distribution<_IntType> _Eng;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    double __p;
+    __is >> __p;
+    if (!__is.fail())
+        __x.param(param_type(__p));
+    return __is;
+}
+
+// chi_squared_distribution
+
+template<class _RealType = double>
+class _LIBCPP_TEMPLATE_VIS chi_squared_distribution
+{
+public:
+    // types
+    typedef _RealType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        result_type __n_;
+    public:
+        typedef chi_squared_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(result_type __n = 1) : __n_(__n) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        result_type n() const {return __n_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__n_ == __y.__n_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructor and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    chi_squared_distribution() : chi_squared_distribution(1) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit chi_squared_distribution(result_type __n)
+        : __p_(param_type(__n)) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit chi_squared_distribution(result_type __n = 1)
+        : __p_(param_type(__n)) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit chi_squared_distribution(const param_type& __p)
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g, const param_type& __p)
+        {return gamma_distribution<result_type>(__p.n() / 2, 2)(__g);}
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type n() const {return __p_.n();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return numeric_limits<result_type>::infinity();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const chi_squared_distribution& __x,
+                        const chi_squared_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const chi_squared_distribution& __x,
+                        const chi_squared_distribution& __y)
+        {return !(__x == __y);}
+};
+
+template <class _CharT, class _Traits, class _RT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const chi_squared_distribution<_RT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    __os << __x.n();
+    return __os;
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           chi_squared_distribution<_RT>& __x)
+{
+    typedef chi_squared_distribution<_RT> _Eng;
+    typedef typename _Eng::result_type result_type;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    result_type __n;
+    __is >> __n;
+    if (!__is.fail())
+        __x.param(param_type(__n));
+    return __is;
+}
+
+// cauchy_distribution
+
+template<class _RealType = double>
+class _LIBCPP_TEMPLATE_VIS cauchy_distribution
+{
+public:
+    // types
+    typedef _RealType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        result_type __a_;
+        result_type __b_;
+    public:
+        typedef cauchy_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(result_type __a = 0, result_type __b = 1)
+            : __a_(__a), __b_(__b) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        result_type a() const {return __a_;}
+        _LIBCPP_INLINE_VISIBILITY
+        result_type b() const {return __b_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructor and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    cauchy_distribution() : cauchy_distribution(0) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit cauchy_distribution(result_type __a, result_type __b = 1)
+        : __p_(param_type(__a, __b)) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit cauchy_distribution(result_type __a = 0, result_type __b = 1)
+        : __p_(param_type(__a, __b)) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit cauchy_distribution(const param_type& __p)
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> _LIBCPP_INLINE_VISIBILITY result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type a() const {return __p_.a();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type b() const {return __p_.b();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return -numeric_limits<result_type>::infinity();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return numeric_limits<result_type>::infinity();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const cauchy_distribution& __x,
+                        const cauchy_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const cauchy_distribution& __x,
+                        const cauchy_distribution& __y)
+        {return !(__x == __y);}
+};
+
+template <class _RealType>
+template<class _URNG>
+inline
+_RealType
+cauchy_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
+{
+    uniform_real_distribution<result_type> __gen;
+    // purposefully let tan arg get as close to pi/2 as it wants, tan will return a finite
+    return __p.a() + __p.b() * _VSTD::tan(3.1415926535897932384626433832795 * __gen(__g));
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const cauchy_distribution<_RT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    __os << __x.a() << __sp << __x.b();
+    return __os;
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           cauchy_distribution<_RT>& __x)
+{
+    typedef cauchy_distribution<_RT> _Eng;
+    typedef typename _Eng::result_type result_type;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    result_type __a;
+    result_type __b;
+    __is >> __a >> __b;
+    if (!__is.fail())
+        __x.param(param_type(__a, __b));
+    return __is;
+}
+
+// fisher_f_distribution
+
+template<class _RealType = double>
+class _LIBCPP_TEMPLATE_VIS fisher_f_distribution
+{
+public:
+    // types
+    typedef _RealType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        result_type __m_;
+        result_type __n_;
+    public:
+        typedef fisher_f_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(result_type __m = 1, result_type __n = 1)
+            : __m_(__m), __n_(__n) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        result_type m() const {return __m_;}
+        _LIBCPP_INLINE_VISIBILITY
+        result_type n() const {return __n_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__m_ == __y.__m_ && __x.__n_ == __y.__n_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructor and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    fisher_f_distribution() : fisher_f_distribution(1) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit fisher_f_distribution(result_type __m, result_type __n = 1)
+        : __p_(param_type(__m, __n)) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit fisher_f_distribution(result_type __m = 1, result_type __n = 1)
+        : __p_(param_type(__m, __n)) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit fisher_f_distribution(const param_type& __p)
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type m() const {return __p_.m();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type n() const {return __p_.n();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return numeric_limits<result_type>::infinity();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const fisher_f_distribution& __x,
+                        const fisher_f_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const fisher_f_distribution& __x,
+                        const fisher_f_distribution& __y)
+        {return !(__x == __y);}
+};
+
+template <class _RealType>
+template<class _URNG>
+_RealType
+fisher_f_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
+{
+    gamma_distribution<result_type> __gdm(__p.m() * result_type(.5));
+    gamma_distribution<result_type> __gdn(__p.n() * result_type(.5));
+    return __p.n() * __gdm(__g) / (__p.m() * __gdn(__g));
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const fisher_f_distribution<_RT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    __os << __x.m() << __sp << __x.n();
+    return __os;
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           fisher_f_distribution<_RT>& __x)
+{
+    typedef fisher_f_distribution<_RT> _Eng;
+    typedef typename _Eng::result_type result_type;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    result_type __m;
+    result_type __n;
+    __is >> __m >> __n;
+    if (!__is.fail())
+        __x.param(param_type(__m, __n));
+    return __is;
+}
+
+// student_t_distribution
+
+template<class _RealType = double>
+class _LIBCPP_TEMPLATE_VIS student_t_distribution
+{
+public:
+    // types
+    typedef _RealType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        result_type __n_;
+    public:
+        typedef student_t_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        explicit param_type(result_type __n = 1) : __n_(__n) {}
+
+        _LIBCPP_INLINE_VISIBILITY
+        result_type n() const {return __n_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__n_ == __y.__n_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+    };
+
+private:
+    param_type __p_;
+    normal_distribution<result_type> __nd_;
+
+public:
+    // constructor and reset functions
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    student_t_distribution() : student_t_distribution(1) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit student_t_distribution(result_type __n)
+        : __p_(param_type(__n)) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    explicit student_t_distribution(result_type __n = 1)
+        : __p_(param_type(__n)) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit student_t_distribution(const param_type& __p)
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {__nd_.reset();}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    result_type n() const {return __p_.n();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return -numeric_limits<result_type>::infinity();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return numeric_limits<result_type>::infinity();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const student_t_distribution& __x,
+                        const student_t_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const student_t_distribution& __x,
+                        const student_t_distribution& __y)
+        {return !(__x == __y);}
+};
+
+template <class _RealType>
+template<class _URNG>
+_RealType
+student_t_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
+{
+    gamma_distribution<result_type> __gd(__p.n() * .5, 2);
+    return __nd_(__g) * _VSTD::sqrt(__p.n()/__gd(__g));
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const student_t_distribution<_RT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    __os << __x.n();
+    return __os;
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           student_t_distribution<_RT>& __x)
+{
+    typedef student_t_distribution<_RT> _Eng;
+    typedef typename _Eng::result_type result_type;
+    typedef typename _Eng::param_type param_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    result_type __n;
+    __is >> __n;
+    if (!__is.fail())
+        __x.param(param_type(__n));
+    return __is;
+}
+
+// discrete_distribution
+
+template<class _IntType = int>
+class _LIBCPP_TEMPLATE_VIS discrete_distribution
+{
+public:
+    // types
+    typedef _IntType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        vector<double> __p_;
+    public:
+        typedef discrete_distribution distribution_type;
+
+        _LIBCPP_INLINE_VISIBILITY
+        param_type() {}
+        template<class _InputIterator>
+            _LIBCPP_INLINE_VISIBILITY
+            param_type(_InputIterator __f, _InputIterator __l)
+            : __p_(__f, __l) {__init();}
+#ifndef _LIBCPP_CXX03_LANG
+        _LIBCPP_INLINE_VISIBILITY
+        param_type(initializer_list<double> __wl)
+            : __p_(__wl.begin(), __wl.end()) {__init();}
+#endif // _LIBCPP_CXX03_LANG
+        template<class _UnaryOperation>
+            param_type(size_t __nw, double __xmin, double __xmax,
+                       _UnaryOperation __fw);
+
+        vector<double> probabilities() const;
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__p_ == __y.__p_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+
+    private:
+        void __init();
+
+        friend class discrete_distribution;
+
+        template <class _CharT, class _Traits, class _IT>
+        friend
+        basic_ostream<_CharT, _Traits>&
+        operator<<(basic_ostream<_CharT, _Traits>& __os,
+                   const discrete_distribution<_IT>& __x);
+
+        template <class _CharT, class _Traits, class _IT>
+        friend
+        basic_istream<_CharT, _Traits>&
+        operator>>(basic_istream<_CharT, _Traits>& __is,
+                   discrete_distribution<_IT>& __x);
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructor and reset functions
+    _LIBCPP_INLINE_VISIBILITY
+    discrete_distribution() {}
+    template<class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        discrete_distribution(_InputIterator __f, _InputIterator __l)
+            : __p_(__f, __l) {}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    discrete_distribution(initializer_list<double> __wl)
+        : __p_(__wl) {}
+#endif // _LIBCPP_CXX03_LANG
+    template<class _UnaryOperation>
+        _LIBCPP_INLINE_VISIBILITY
+        discrete_distribution(size_t __nw, double __xmin, double __xmax,
+                              _UnaryOperation __fw)
+        : __p_(__nw, __xmin, __xmax, __fw) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit discrete_distribution(const param_type& __p)
+        : __p_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    vector<double> probabilities() const {return __p_.probabilities();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return __p_.__p_.size();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const discrete_distribution& __x,
+                        const discrete_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const discrete_distribution& __x,
+                        const discrete_distribution& __y)
+        {return !(__x == __y);}
+
+    template <class _CharT, class _Traits, class _IT>
+    friend
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+               const discrete_distribution<_IT>& __x);
+
+    template <class _CharT, class _Traits, class _IT>
+    friend
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is,
+               discrete_distribution<_IT>& __x);
+};
+
+template<class _IntType>
+template<class _UnaryOperation>
+discrete_distribution<_IntType>::param_type::param_type(size_t __nw,
+                                                        double __xmin,
+                                                        double __xmax,
+                                                        _UnaryOperation __fw)
+{
+    if (__nw > 1)
+    {
+        __p_.reserve(__nw - 1);
+        double __d = (__xmax - __xmin) / __nw;
+        double __d2 = __d / 2;
+        for (size_t __k = 0; __k < __nw; ++__k)
+            __p_.push_back(__fw(__xmin + __k * __d + __d2));
+        __init();
+    }
+}
+
+template<class _IntType>
+void
+discrete_distribution<_IntType>::param_type::__init()
+{
+    if (!__p_.empty())
+    {
+        if (__p_.size() > 1)
+        {
+            double __s = _VSTD::accumulate(__p_.begin(), __p_.end(), 0.0);
+            for (vector<double>::iterator __i = __p_.begin(), __e = __p_.end(); __i < __e; ++__i)
+                *__i /= __s;
+            vector<double> __t(__p_.size() - 1);
+            _VSTD::partial_sum(__p_.begin(), __p_.end() - 1, __t.begin());
+            swap(__p_, __t);
+        }
+        else
+        {
+            __p_.clear();
+            __p_.shrink_to_fit();
+        }
+    }
+}
+
+template<class _IntType>
+vector<double>
+discrete_distribution<_IntType>::param_type::probabilities() const
+{
+    size_t __n = __p_.size();
+    vector<double> __p(__n+1);
+    _VSTD::adjacent_difference(__p_.begin(), __p_.end(), __p.begin());
+    if (__n > 0)
+        __p[__n] = 1 - __p_[__n-1];
+    else
+        __p[0] = 1;
+    return __p;
+}
+
+template<class _IntType>
+template<class _URNG>
+_IntType
+discrete_distribution<_IntType>::operator()(_URNG& __g, const param_type& __p)
+{
+    uniform_real_distribution<double> __gen;
+    return static_cast<_IntType>(
+           _VSTD::upper_bound(__p.__p_.begin(), __p.__p_.end(), __gen(__g)) -
+                                                              __p.__p_.begin());
+}
+
+template <class _CharT, class _Traits, class _IT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const discrete_distribution<_IT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    size_t __n = __x.__p_.__p_.size();
+    __os << __n;
+    for (size_t __i = 0; __i < __n; ++__i)
+        __os << __sp << __x.__p_.__p_[__i];
+    return __os;
+}
+
+template <class _CharT, class _Traits, class _IT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           discrete_distribution<_IT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    size_t __n;
+    __is >> __n;
+    vector<double> __p(__n);
+    for (size_t __i = 0; __i < __n; ++__i)
+        __is >> __p[__i];
+    if (!__is.fail())
+        swap(__x.__p_.__p_, __p);
+    return __is;
+}
+
+// piecewise_constant_distribution
+
+template<class _RealType = double>
+class _LIBCPP_TEMPLATE_VIS piecewise_constant_distribution
+{
+public:
+    // types
+    typedef _RealType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        vector<result_type> __b_;
+        vector<result_type> __densities_;
+        vector<result_type> __areas_;
+    public:
+        typedef piecewise_constant_distribution distribution_type;
+
+        param_type();
+        template<class _InputIteratorB, class _InputIteratorW>
+            param_type(_InputIteratorB __fB, _InputIteratorB __lB,
+                       _InputIteratorW __fW);
+#ifndef _LIBCPP_CXX03_LANG
+        template<class _UnaryOperation>
+            param_type(initializer_list<result_type> __bl, _UnaryOperation __fw);
+#endif // _LIBCPP_CXX03_LANG
+        template<class _UnaryOperation>
+            param_type(size_t __nw, result_type __xmin, result_type __xmax,
+                       _UnaryOperation __fw);
+        param_type(param_type const&) = default;
+        param_type & operator=(const param_type& __rhs);
+
+        _LIBCPP_INLINE_VISIBILITY
+        vector<result_type> intervals() const {return __b_;}
+        _LIBCPP_INLINE_VISIBILITY
+        vector<result_type> densities() const {return __densities_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__densities_ == __y.__densities_ && __x.__b_ == __y.__b_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+
+    private:
+        void __init();
+
+        friend class piecewise_constant_distribution;
+
+        template <class _CharT, class _Traits, class _RT>
+        friend
+        basic_ostream<_CharT, _Traits>&
+        operator<<(basic_ostream<_CharT, _Traits>& __os,
+                   const piecewise_constant_distribution<_RT>& __x);
+
+        template <class _CharT, class _Traits, class _RT>
+        friend
+        basic_istream<_CharT, _Traits>&
+        operator>>(basic_istream<_CharT, _Traits>& __is,
+                   piecewise_constant_distribution<_RT>& __x);
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructor and reset functions
+    _LIBCPP_INLINE_VISIBILITY
+    piecewise_constant_distribution() {}
+    template<class _InputIteratorB, class _InputIteratorW>
+        _LIBCPP_INLINE_VISIBILITY
+        piecewise_constant_distribution(_InputIteratorB __fB,
+                                        _InputIteratorB __lB,
+                                        _InputIteratorW __fW)
+        : __p_(__fB, __lB, __fW) {}
+
+#ifndef _LIBCPP_CXX03_LANG
+    template<class _UnaryOperation>
+        _LIBCPP_INLINE_VISIBILITY
+        piecewise_constant_distribution(initializer_list<result_type> __bl,
+                                        _UnaryOperation __fw)
+        : __p_(__bl, __fw) {}
+#endif // _LIBCPP_CXX03_LANG
+
+    template<class _UnaryOperation>
+        _LIBCPP_INLINE_VISIBILITY
+        piecewise_constant_distribution(size_t __nw, result_type __xmin,
+                                        result_type __xmax, _UnaryOperation __fw)
+        : __p_(__nw, __xmin, __xmax, __fw) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit piecewise_constant_distribution(const param_type& __p)
+        : __p_(__p) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    vector<result_type> intervals() const {return __p_.intervals();}
+    _LIBCPP_INLINE_VISIBILITY
+    vector<result_type> densities() const {return __p_.densities();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return __p_.__b_.front();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return __p_.__b_.back();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const piecewise_constant_distribution& __x,
+                        const piecewise_constant_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const piecewise_constant_distribution& __x,
+                           const piecewise_constant_distribution& __y)
+        {return !(__x == __y);}
+
+    template <class _CharT, class _Traits, class _RT>
+    friend
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+               const piecewise_constant_distribution<_RT>& __x);
+
+    template <class _CharT, class _Traits, class _RT>
+    friend
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is,
+               piecewise_constant_distribution<_RT>& __x);
+};
+
+template<class _RealType>
+typename piecewise_constant_distribution<_RealType>::param_type &
+piecewise_constant_distribution<_RealType>::param_type::operator=
+                                                       (const param_type& __rhs)
+{
+//  These can throw
+    __b_.reserve        (__rhs.__b_.size ());
+    __densities_.reserve(__rhs.__densities_.size());
+    __areas_.reserve    (__rhs.__areas_.size());
+
+//  These can not throw
+    __b_         = __rhs.__b_;
+    __densities_ = __rhs.__densities_;
+    __areas_     =  __rhs.__areas_;
+    return *this;
+}
+
+template<class _RealType>
+void
+piecewise_constant_distribution<_RealType>::param_type::__init()
+{
+    // __densities_ contains non-normalized areas
+    result_type __total_area = _VSTD::accumulate(__densities_.begin(),
+                                                __densities_.end(),
+                                                result_type());
+    for (size_t __i = 0; __i < __densities_.size(); ++__i)
+        __densities_[__i] /= __total_area;
+    // __densities_ contains normalized areas
+    __areas_.assign(__densities_.size(), result_type());
+    _VSTD::partial_sum(__densities_.begin(), __densities_.end() - 1,
+                                                          __areas_.begin() + 1);
+    // __areas_ contains partial sums of normalized areas: [0, __densities_ - 1]
+    __densities_.back() = 1 - __areas_.back();  // correct round off error
+    for (size_t __i = 0; __i < __densities_.size(); ++__i)
+        __densities_[__i] /= (__b_[__i+1] - __b_[__i]);
+    // __densities_ now contains __densities_
+}
+
+template<class _RealType>
+piecewise_constant_distribution<_RealType>::param_type::param_type()
+    : __b_(2),
+      __densities_(1, 1.0),
+      __areas_(1, 0.0)
+{
+    __b_[1] = 1;
+}
+
+template<class _RealType>
+template<class _InputIteratorB, class _InputIteratorW>
+piecewise_constant_distribution<_RealType>::param_type::param_type(
+        _InputIteratorB __fB, _InputIteratorB __lB, _InputIteratorW __fW)
+    : __b_(__fB, __lB)
+{
+    if (__b_.size() < 2)
+    {
+        __b_.resize(2);
+        __b_[0] = 0;
+        __b_[1] = 1;
+        __densities_.assign(1, 1.0);
+        __areas_.assign(1, 0.0);
+    }
+    else
+    {
+        __densities_.reserve(__b_.size() - 1);
+        for (size_t __i = 0; __i < __b_.size() - 1; ++__i, ++__fW)
+            __densities_.push_back(*__fW);
+        __init();
+    }
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _RealType>
+template<class _UnaryOperation>
+piecewise_constant_distribution<_RealType>::param_type::param_type(
+        initializer_list<result_type> __bl, _UnaryOperation __fw)
+    : __b_(__bl.begin(), __bl.end())
+{
+    if (__b_.size() < 2)
+    {
+        __b_.resize(2);
+        __b_[0] = 0;
+        __b_[1] = 1;
+        __densities_.assign(1, 1.0);
+        __areas_.assign(1, 0.0);
+    }
+    else
+    {
+        __densities_.reserve(__b_.size() - 1);
+        for (size_t __i = 0; __i < __b_.size() - 1; ++__i)
+            __densities_.push_back(__fw((__b_[__i+1] + __b_[__i])*.5));
+        __init();
+    }
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template<class _RealType>
+template<class _UnaryOperation>
+piecewise_constant_distribution<_RealType>::param_type::param_type(
+        size_t __nw, result_type __xmin, result_type __xmax, _UnaryOperation __fw)
+    : __b_(__nw == 0 ? 2 : __nw + 1)
+{
+    size_t __n = __b_.size() - 1;
+    result_type __d = (__xmax - __xmin) / __n;
+    __densities_.reserve(__n);
+    for (size_t __i = 0; __i < __n; ++__i)
+    {
+        __b_[__i] = __xmin + __i * __d;
+        __densities_.push_back(__fw(__b_[__i] + __d*.5));
+    }
+    __b_[__n] = __xmax;
+    __init();
+}
+
+template<class _RealType>
+template<class _URNG>
+_RealType
+piecewise_constant_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
+{
+    typedef uniform_real_distribution<result_type> _Gen;
+    result_type __u = _Gen()(__g);
+    ptrdiff_t __k = _VSTD::upper_bound(__p.__areas_.begin(), __p.__areas_.end(),
+                                      __u) - __p.__areas_.begin() - 1;
+    return (__u - __p.__areas_[__k]) / __p.__densities_[__k] + __p.__b_[__k];
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const piecewise_constant_distribution<_RT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    size_t __n = __x.__p_.__b_.size();
+    __os << __n;
+    for (size_t __i = 0; __i < __n; ++__i)
+        __os << __sp << __x.__p_.__b_[__i];
+    __n = __x.__p_.__densities_.size();
+    __os << __sp << __n;
+    for (size_t __i = 0; __i < __n; ++__i)
+        __os << __sp << __x.__p_.__densities_[__i];
+    __n = __x.__p_.__areas_.size();
+    __os << __sp << __n;
+    for (size_t __i = 0; __i < __n; ++__i)
+        __os << __sp << __x.__p_.__areas_[__i];
+    return __os;
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           piecewise_constant_distribution<_RT>& __x)
+{
+    typedef piecewise_constant_distribution<_RT> _Eng;
+    typedef typename _Eng::result_type result_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    size_t __n;
+    __is >> __n;
+    vector<result_type> __b(__n);
+    for (size_t __i = 0; __i < __n; ++__i)
+        __is >> __b[__i];
+    __is >> __n;
+    vector<result_type> __densities(__n);
+    for (size_t __i = 0; __i < __n; ++__i)
+        __is >> __densities[__i];
+    __is >> __n;
+    vector<result_type> __areas(__n);
+    for (size_t __i = 0; __i < __n; ++__i)
+        __is >> __areas[__i];
+    if (!__is.fail())
+    {
+        swap(__x.__p_.__b_, __b);
+        swap(__x.__p_.__densities_, __densities);
+        swap(__x.__p_.__areas_, __areas);
+    }
+    return __is;
+}
+
+// piecewise_linear_distribution
+
+template<class _RealType = double>
+class _LIBCPP_TEMPLATE_VIS piecewise_linear_distribution
+{
+public:
+    // types
+    typedef _RealType result_type;
+
+    class _LIBCPP_TEMPLATE_VIS param_type
+    {
+        vector<result_type> __b_;
+        vector<result_type> __densities_;
+        vector<result_type> __areas_;
+    public:
+        typedef piecewise_linear_distribution distribution_type;
+
+        param_type();
+        template<class _InputIteratorB, class _InputIteratorW>
+            param_type(_InputIteratorB __fB, _InputIteratorB __lB,
+                       _InputIteratorW __fW);
+#ifndef _LIBCPP_CXX03_LANG
+        template<class _UnaryOperation>
+            param_type(initializer_list<result_type> __bl, _UnaryOperation __fw);
+#endif // _LIBCPP_CXX03_LANG
+        template<class _UnaryOperation>
+            param_type(size_t __nw, result_type __xmin, result_type __xmax,
+                       _UnaryOperation __fw);
+        param_type(param_type const&) = default;
+        param_type & operator=(const param_type& __rhs);
+
+        _LIBCPP_INLINE_VISIBILITY
+        vector<result_type> intervals() const {return __b_;}
+        _LIBCPP_INLINE_VISIBILITY
+        vector<result_type> densities() const {return __densities_;}
+
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator==(const param_type& __x, const param_type& __y)
+            {return __x.__densities_ == __y.__densities_ && __x.__b_ == __y.__b_;}
+        friend _LIBCPP_INLINE_VISIBILITY
+            bool operator!=(const param_type& __x, const param_type& __y)
+            {return !(__x == __y);}
+
+    private:
+        void __init();
+
+        friend class piecewise_linear_distribution;
+
+        template <class _CharT, class _Traits, class _RT>
+        friend
+        basic_ostream<_CharT, _Traits>&
+        operator<<(basic_ostream<_CharT, _Traits>& __os,
+                   const piecewise_linear_distribution<_RT>& __x);
+
+        template <class _CharT, class _Traits, class _RT>
+        friend
+        basic_istream<_CharT, _Traits>&
+        operator>>(basic_istream<_CharT, _Traits>& __is,
+                   piecewise_linear_distribution<_RT>& __x);
+    };
+
+private:
+    param_type __p_;
+
+public:
+    // constructor and reset functions
+    _LIBCPP_INLINE_VISIBILITY
+    piecewise_linear_distribution() {}
+    template<class _InputIteratorB, class _InputIteratorW>
+        _LIBCPP_INLINE_VISIBILITY
+        piecewise_linear_distribution(_InputIteratorB __fB,
+                                      _InputIteratorB __lB,
+                                      _InputIteratorW __fW)
+        : __p_(__fB, __lB, __fW) {}
+
+#ifndef _LIBCPP_CXX03_LANG
+    template<class _UnaryOperation>
+        _LIBCPP_INLINE_VISIBILITY
+        piecewise_linear_distribution(initializer_list<result_type> __bl,
+                                      _UnaryOperation __fw)
+        : __p_(__bl, __fw) {}
+#endif // _LIBCPP_CXX03_LANG
+
+    template<class _UnaryOperation>
+        _LIBCPP_INLINE_VISIBILITY
+        piecewise_linear_distribution(size_t __nw, result_type __xmin,
+                                      result_type __xmax, _UnaryOperation __fw)
+        : __p_(__nw, __xmin, __xmax, __fw) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit piecewise_linear_distribution(const param_type& __p)
+        : __p_(__p) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void reset() {}
+
+    // generating functions
+    template<class _URNG>
+        _LIBCPP_INLINE_VISIBILITY
+        result_type operator()(_URNG& __g)
+        {return (*this)(__g, __p_);}
+    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
+
+    // property functions
+    _LIBCPP_INLINE_VISIBILITY
+    vector<result_type> intervals() const {return __p_.intervals();}
+    _LIBCPP_INLINE_VISIBILITY
+    vector<result_type> densities() const {return __p_.densities();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    param_type param() const {return __p_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void param(const param_type& __p) {__p_ = __p;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    result_type min() const {return __p_.__b_.front();}
+    _LIBCPP_INLINE_VISIBILITY
+    result_type max() const {return __p_.__b_.back();}
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const piecewise_linear_distribution& __x,
+                        const piecewise_linear_distribution& __y)
+        {return __x.__p_ == __y.__p_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const piecewise_linear_distribution& __x,
+                        const piecewise_linear_distribution& __y)
+        {return !(__x == __y);}
+
+    template <class _CharT, class _Traits, class _RT>
+    friend
+    basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+               const piecewise_linear_distribution<_RT>& __x);
+
+    template <class _CharT, class _Traits, class _RT>
+    friend
+    basic_istream<_CharT, _Traits>&
+    operator>>(basic_istream<_CharT, _Traits>& __is,
+               piecewise_linear_distribution<_RT>& __x);
+};
+
+template<class _RealType>
+typename piecewise_linear_distribution<_RealType>::param_type &
+piecewise_linear_distribution<_RealType>::param_type::operator=
+                                                       (const param_type& __rhs)
+{
+//  These can throw
+    __b_.reserve        (__rhs.__b_.size ());
+    __densities_.reserve(__rhs.__densities_.size());
+    __areas_.reserve    (__rhs.__areas_.size());
+
+//  These can not throw
+    __b_         = __rhs.__b_;
+    __densities_ = __rhs.__densities_;
+    __areas_     =  __rhs.__areas_;
+    return *this;
+}
+
+
+template<class _RealType>
+void
+piecewise_linear_distribution<_RealType>::param_type::__init()
+{
+    __areas_.assign(__densities_.size() - 1, result_type());
+    result_type _Sp = 0;
+    for (size_t __i = 0; __i < __areas_.size(); ++__i)
+    {
+        __areas_[__i] = (__densities_[__i+1] + __densities_[__i]) *
+                        (__b_[__i+1] - __b_[__i]) * .5;
+        _Sp += __areas_[__i];
+    }
+    for (size_t __i = __areas_.size(); __i > 1;)
+    {
+        --__i;
+        __areas_[__i] = __areas_[__i-1] / _Sp;
+    }
+    __areas_[0] = 0;
+    for (size_t __i = 1; __i < __areas_.size(); ++__i)
+        __areas_[__i] += __areas_[__i-1];
+    for (size_t __i = 0; __i < __densities_.size(); ++__i)
+        __densities_[__i] /= _Sp;
+}
+
+template<class _RealType>
+piecewise_linear_distribution<_RealType>::param_type::param_type()
+    : __b_(2),
+      __densities_(2, 1.0),
+      __areas_(1, 0.0)
+{
+    __b_[1] = 1;
+}
+
+template<class _RealType>
+template<class _InputIteratorB, class _InputIteratorW>
+piecewise_linear_distribution<_RealType>::param_type::param_type(
+        _InputIteratorB __fB, _InputIteratorB __lB, _InputIteratorW __fW)
+    : __b_(__fB, __lB)
+{
+    if (__b_.size() < 2)
+    {
+        __b_.resize(2);
+        __b_[0] = 0;
+        __b_[1] = 1;
+        __densities_.assign(2, 1.0);
+        __areas_.assign(1, 0.0);
+    }
+    else
+    {
+        __densities_.reserve(__b_.size());
+        for (size_t __i = 0; __i < __b_.size(); ++__i, ++__fW)
+            __densities_.push_back(*__fW);
+        __init();
+    }
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _RealType>
+template<class _UnaryOperation>
+piecewise_linear_distribution<_RealType>::param_type::param_type(
+        initializer_list<result_type> __bl, _UnaryOperation __fw)
+    : __b_(__bl.begin(), __bl.end())
+{
+    if (__b_.size() < 2)
+    {
+        __b_.resize(2);
+        __b_[0] = 0;
+        __b_[1] = 1;
+        __densities_.assign(2, 1.0);
+        __areas_.assign(1, 0.0);
+    }
+    else
+    {
+        __densities_.reserve(__b_.size());
+        for (size_t __i = 0; __i < __b_.size(); ++__i)
+            __densities_.push_back(__fw(__b_[__i]));
+        __init();
+    }
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template<class _RealType>
+template<class _UnaryOperation>
+piecewise_linear_distribution<_RealType>::param_type::param_type(
+        size_t __nw, result_type __xmin, result_type __xmax, _UnaryOperation __fw)
+    : __b_(__nw == 0 ? 2 : __nw + 1)
+{
+    size_t __n = __b_.size() - 1;
+    result_type __d = (__xmax - __xmin) / __n;
+    __densities_.reserve(__b_.size());
+    for (size_t __i = 0; __i < __n; ++__i)
+    {
+        __b_[__i] = __xmin + __i * __d;
+        __densities_.push_back(__fw(__b_[__i]));
+    }
+    __b_[__n] = __xmax;
+    __densities_.push_back(__fw(__b_[__n]));
+    __init();
+}
+
+template<class _RealType>
+template<class _URNG>
+_RealType
+piecewise_linear_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
+{
+    typedef uniform_real_distribution<result_type> _Gen;
+    result_type __u = _Gen()(__g);
+    ptrdiff_t __k = _VSTD::upper_bound(__p.__areas_.begin(), __p.__areas_.end(),
+                                      __u) - __p.__areas_.begin() - 1;
+    __u -= __p.__areas_[__k];
+    const result_type __dk = __p.__densities_[__k];
+    const result_type __dk1 = __p.__densities_[__k+1];
+    const result_type __deltad = __dk1 - __dk;
+    const result_type __bk = __p.__b_[__k];
+    if (__deltad == 0)
+        return __u / __dk + __bk;
+    const result_type __bk1 = __p.__b_[__k+1];
+    const result_type __deltab = __bk1 - __bk;
+    return (__bk * __dk1 - __bk1 * __dk +
+        _VSTD::sqrt(__deltab * (__deltab * __dk * __dk + 2 * __deltad * __u))) /
+        __deltad;
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const piecewise_linear_distribution<_RT>& __x)
+{
+    __save_flags<_CharT, _Traits> __lx(__os);
+    typedef basic_ostream<_CharT, _Traits> _OStream;
+    __os.flags(_OStream::dec | _OStream::left | _OStream::fixed |
+               _OStream::scientific);
+    _CharT __sp = __os.widen(' ');
+    __os.fill(__sp);
+    size_t __n = __x.__p_.__b_.size();
+    __os << __n;
+    for (size_t __i = 0; __i < __n; ++__i)
+        __os << __sp << __x.__p_.__b_[__i];
+    __n = __x.__p_.__densities_.size();
+    __os << __sp << __n;
+    for (size_t __i = 0; __i < __n; ++__i)
+        __os << __sp << __x.__p_.__densities_[__i];
+    __n = __x.__p_.__areas_.size();
+    __os << __sp << __n;
+    for (size_t __i = 0; __i < __n; ++__i)
+        __os << __sp << __x.__p_.__areas_[__i];
+    return __os;
+}
+
+template <class _CharT, class _Traits, class _RT>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           piecewise_linear_distribution<_RT>& __x)
+{
+    typedef piecewise_linear_distribution<_RT> _Eng;
+    typedef typename _Eng::result_type result_type;
+    __save_flags<_CharT, _Traits> __lx(__is);
+    typedef basic_istream<_CharT, _Traits> _Istream;
+    __is.flags(_Istream::dec | _Istream::skipws);
+    size_t __n;
+    __is >> __n;
+    vector<result_type> __b(__n);
+    for (size_t __i = 0; __i < __n; ++__i)
+        __is >> __b[__i];
+    __is >> __n;
+    vector<result_type> __densities(__n);
+    for (size_t __i = 0; __i < __n; ++__i)
+        __is >> __densities[__i];
+    __is >> __n;
+    vector<result_type> __areas(__n);
+    for (size_t __i = 0; __i < __n; ++__i)
+        __is >> __areas[__i];
+    if (!__is.fail())
+    {
+        swap(__x.__p_.__b_, __b);
+        swap(__x.__p_.__densities_, __densities);
+        swap(__x.__p_.__areas_, __areas);
+    }
+    return __is;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_RANDOM
diff --git a/contrib/libs/cxxsupp/libcxx/include/ranges b/contrib/libs/cxxsupp/libcxx/include/ranges
new file mode 100644
index 00000000000..58bdbf39190
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/ranges
@@ -0,0 +1,245 @@
+// -*- C++ -*-
+//===--------------------------- ranges -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_RANGES
+#define _LIBCPP_RANGES
+
+/*
+
+#include <compare>              // see [compare.syn]
+#include <initializer_list>     // see [initializer.list.syn]
+#include <iterator>             // see [iterator.synopsis]
+
+namespace std::ranges {
+  inline namespace unspecified {
+    // [range.access], range access
+    inline constexpr unspecified begin = unspecified;
+    inline constexpr unspecified end = unspecified;
+    inline constexpr unspecified cbegin = unspecified;
+    inline constexpr unspecified cend = unspecified;
+
+    inline constexpr unspecified size = unspecified;
+    inline constexpr unspecified ssize = unspecified;
+  }
+
+  // [range.range], ranges
+  template<class T>
+    concept range = see below;
+
+  template<class T>
+    inline constexpr bool enable_borrowed_range = false;
+
+  template<class T>
+    using iterator_t = decltype(ranges::begin(declval<R&>()));
+  template<range R>
+    using sentinel_t = decltype(ranges::end(declval<R&>()));
+  template<range R>
+    using range_difference_t = iter_difference_t<iterator_t<R>>;
+  template<sized_range R>
+    using range_size_t = decltype(ranges::size(declval<R&>()));
+  template<range R>
+    using range_value_t = iter_value_t<iterator_t<R>>;
+  template<range R>
+    using range_reference_t = iter_reference_t<iterator_t<R>>;
+  template<range R>
+    using range_rvalue_reference_t = iter_rvalue_reference_t<iterator_t<R>>;
+
+  // [range.sized], sized ranges
+  template<class>
+    inline constexpr bool disable_sized_range = false;
+
+  template<class T>
+    concept sized_range = ...;
+
+  // [range.view], views
+  template<class T>
+    inline constexpr bool enable_view = ...;
+
+  struct view_base { };
+
+  template<class T>
+    concept view = ...;
+
+  // [range.refinements], other range refinements
+  template<class R, class T>
+    concept output_range = see below;
+
+  template<class T>
+    concept input_range = see below;
+
+  template<class T>
+    concept forward_range = see below;
+
+  template<class T>
+  concept bidirectional_range = see below;
+
+  template<class T>
+  concept random_access_range = see below;
+
+  template<class T>
+  concept contiguous_range = see below;
+
+  template <class _Tp>
+    concept common_range = see below;
+
+  template<class T>
+  concept viewable_range = see below;
+
+  // [view.interface], class template view_interface
+  template<class D>
+    requires is_class_v<D> && same_as<D, remove_cv_t<D>>
+  class view_interface;
+
+  // [range.subrange], sub-ranges
+  enum class subrange_kind : bool { unsized, sized };
+
+  template<input_or_output_iterator I, sentinel_for<I> S = I, subrange_kind K = see below>
+    requires (K == subrange_kind::sized || !sized_sentinel_for<S, I>)
+  class subrange;
+
+  template<class I, class S, subrange_kind K>
+    inline constexpr bool enable_borrowed_range<subrange<I, S, K>> = true;
+
+  // [range.dangling], dangling iterator handling
+  struct dangling;
+
+  template<range R>
+    using borrowed_iterator_t = see below;
+
+  template<range R>
+    using borrowed_subrange_t = see below;
+
+  // [range.empty], empty view
+  template<class T>
+    requires is_object_v<T>
+  class empty_view;
+
+  // [range.all], all view
+  namespace views {
+    inline constexpr unspecified all = unspecified;
+
+    template<viewable_range R>
+      using all_t = decltype(all(declval<R>()));
+  }
+
+  template<range R>
+    requires is_object_v<R>
+  class ref_view;
+
+  template<class T>
+    inline constexpr bool enable_borrowed_range<ref_view<T>> = true;
+
+  // [range.drop], drop view
+  template<view V>
+    class drop_view;
+
+  template<class T>
+    inline constexpr bool enable_borrowed_range<drop_view<T>> = enable_borrowed_range<T>;
+
+  // [range.transform], transform view
+  template<input_range V, copy_constructible F>
+    requires view<V> && is_object_v<F> &&
+             regular_invocable<F&, range_reference_t<V>> &&
+             can-reference<invoke_result_t<F&, range_reference_t<V>>>
+  class transform_view;
+
+  // [range.counted], counted view
+  namespace views { inline constexpr unspecified counted = unspecified; }
+
+  // [range.common], common view
+  template<view V>
+    requires (!common_range<V> && copyable<iterator_t<V>>)
+  class common_view;
+
+ // [range.reverse], reverse view
+  template<view V>
+    requires bidirectional_range<V>
+  class reverse_view;
+
+  template<class T>
+    inline constexpr bool enable_borrowed_range<reverse_view<T>> = enable_borrowed_range<T>;
+
+  template<class T>
+  inline constexpr bool enable_borrowed_range<common_view<T>> = enable_borrowed_range<T>;
+
+   // [range.take], take view
+  template<view> class take_view;
+
+  template<class T>
+  inline constexpr bool enable_borrowed_range<take_view<T>> = enable_borrowed_range<T>;
+
+  template<copy_constructible T>
+    requires is_object_v<T>
+  class single_view;
+
+  template<weakly_incrementable W, semiregular Bound = unreachable_sentinel_t>
+    requires weakly-equality-comparable-with<W, Bound> && copyable<W>
+  class iota_view;
+
+  template<class W, class Bound>
+    inline constexpr bool enable_borrowed_range<iota_view<W, Bound>> = true;
+
+  // [range.join], join view
+  template<input_range V>
+    requires view<V> && input_range<range_reference_t<V>>
+  class join_view;
+}
+
+*/
+
+// Make sure all feature-test macros are available.
+#include <version>
+// Enable the contents of the header only when libc++ was built with LIBCXX_ENABLE_INCOMPLETE_FEATURES.
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+#include <__config>
+#include <__ranges/access.h>
+#include <__ranges/all.h>
+#include <__ranges/common_view.h>
+#include <__ranges/concepts.h>
+#include <__ranges/counted.h>
+#include <__ranges/dangling.h>
+#include <__ranges/data.h>
+#include <__ranges/drop_view.h>
+#include <__ranges/empty_view.h>
+#include <__ranges/empty.h>
+#include <__ranges/enable_borrowed_range.h>
+#include <__ranges/enable_view.h>
+#include <__ranges/iota_view.h>
+#include <__ranges/join_view.h>
+#include <__ranges/ref_view.h>
+#include <__ranges/reverse_view.h>
+#include <__ranges/single_view.h>
+#include <__ranges/size.h>
+#include <__ranges/subrange.h>
+#include <__ranges/take_view.h>
+#include <__ranges/transform_view.h>
+#include <__ranges/view_interface.h>
+#include <compare>          // Required by the standard.
+#include <initializer_list> // Required by the standard.
+#include <iterator>         // Required by the standard.
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+
+namespace views = ranges::views;
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+#endif // _LIBCPP_RANGES
diff --git a/contrib/libs/cxxsupp/libcxx/include/ratio b/contrib/libs/cxxsupp/libcxx/include/ratio
new file mode 100644
index 00000000000..16d3b2b831e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/ratio
@@ -0,0 +1,526 @@
+// -*- C++ -*-
+//===---------------------------- ratio -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_RATIO
+#define _LIBCPP_RATIO
+
+/*
+    ratio synopsis
+
+namespace std
+{
+
+template <intmax_t N, intmax_t D = 1>
+class ratio
+{
+public:
+    static constexpr intmax_t num;
+    static constexpr intmax_t den;
+    typedef ratio<num, den> type;
+};
+
+// ratio arithmetic
+template <class R1, class R2> using ratio_add = ...;
+template <class R1, class R2> using ratio_subtract = ...;
+template <class R1, class R2> using ratio_multiply = ...;
+template <class R1, class R2> using ratio_divide = ...;
+
+// ratio comparison
+template <class R1, class R2> struct ratio_equal;
+template <class R1, class R2> struct ratio_not_equal;
+template <class R1, class R2> struct ratio_less;
+template <class R1, class R2> struct ratio_less_equal;
+template <class R1, class R2> struct ratio_greater;
+template <class R1, class R2> struct ratio_greater_equal;
+
+// convenience SI typedefs
+typedef ratio<1, 1000000000000000000000000> yocto;  // not supported
+typedef ratio<1,    1000000000000000000000> zepto;  // not supported
+typedef ratio<1,       1000000000000000000> atto;
+typedef ratio<1,          1000000000000000> femto;
+typedef ratio<1,             1000000000000> pico;
+typedef ratio<1,                1000000000> nano;
+typedef ratio<1,                   1000000> micro;
+typedef ratio<1,                      1000> milli;
+typedef ratio<1,                       100> centi;
+typedef ratio<1,                        10> deci;
+typedef ratio<                       10, 1> deca;
+typedef ratio<                      100, 1> hecto;
+typedef ratio<                     1000, 1> kilo;
+typedef ratio<                  1000000, 1> mega;
+typedef ratio<               1000000000, 1> giga;
+typedef ratio<            1000000000000, 1> tera;
+typedef ratio<         1000000000000000, 1> peta;
+typedef ratio<      1000000000000000000, 1> exa;
+typedef ratio<   1000000000000000000000, 1> zetta;  // not supported
+typedef ratio<1000000000000000000000000, 1> yotta;  // not supported
+
+  // 20.11.5, ratio comparison
+  template <class R1, class R2> inline constexpr bool ratio_equal_v
+    = ratio_equal<R1, R2>::value;                                       // C++17
+  template <class R1, class R2> inline constexpr bool ratio_not_equal_v
+    = ratio_not_equal<R1, R2>::value;                                   // C++17
+  template <class R1, class R2> inline constexpr bool ratio_less_v
+    = ratio_less<R1, R2>::value;                                        // C++17
+  template <class R1, class R2> inline constexpr bool ratio_less_equal_v
+    = ratio_less_equal<R1, R2>::value;                                  // C++17
+  template <class R1, class R2> inline constexpr bool ratio_greater_v
+    = ratio_greater<R1, R2>::value;                                     // C++17
+  template <class R1, class R2> inline constexpr bool ratio_greater_equal_v
+    = ratio_greater_equal<R1, R2>::value;                               // C++17
+}
+*/
+
+#include <__config>
+#include <climits>
+#include <cstdint>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// __static_gcd
+
+template <intmax_t _Xp, intmax_t _Yp>
+struct __static_gcd
+{
+    static const intmax_t value = __static_gcd<_Yp, _Xp % _Yp>::value;
+};
+
+template <intmax_t _Xp>
+struct __static_gcd<_Xp, 0>
+{
+    static const intmax_t value = _Xp;
+};
+
+template <>
+struct __static_gcd<0, 0>
+{
+    static const intmax_t value = 1;
+};
+
+// __static_lcm
+
+template <intmax_t _Xp, intmax_t _Yp>
+struct __static_lcm
+{
+    static const intmax_t value = _Xp / __static_gcd<_Xp, _Yp>::value * _Yp;
+};
+
+template <intmax_t _Xp>
+struct __static_abs
+{
+    static const intmax_t value = _Xp < 0 ? -_Xp : _Xp;
+};
+
+template <intmax_t _Xp>
+struct __static_sign
+{
+    static const intmax_t value = _Xp == 0 ? 0 : (_Xp < 0 ? -1 : 1);
+};
+
+template <intmax_t _Xp, intmax_t _Yp, intmax_t = __static_sign<_Yp>::value>
+class __ll_add;
+
+template <intmax_t _Xp, intmax_t _Yp>
+class __ll_add<_Xp, _Yp, 1>
+{
+    static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
+    static const intmax_t max = -min;
+
+    static_assert(_Xp <= max - _Yp, "overflow in __ll_add");
+public:
+    static const intmax_t value = _Xp + _Yp;
+};
+
+template <intmax_t _Xp, intmax_t _Yp>
+class __ll_add<_Xp, _Yp, 0>
+{
+public:
+    static const intmax_t value = _Xp;
+};
+
+template <intmax_t _Xp, intmax_t _Yp>
+class __ll_add<_Xp, _Yp, -1>
+{
+    static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
+    static const intmax_t max = -min;
+
+    static_assert(min - _Yp <= _Xp, "overflow in __ll_add");
+public:
+    static const intmax_t value = _Xp + _Yp;
+};
+
+template <intmax_t _Xp, intmax_t _Yp, intmax_t = __static_sign<_Yp>::value>
+class __ll_sub;
+
+template <intmax_t _Xp, intmax_t _Yp>
+class __ll_sub<_Xp, _Yp, 1>
+{
+    static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
+    static const intmax_t max = -min;
+
+    static_assert(min + _Yp <= _Xp, "overflow in __ll_sub");
+public:
+    static const intmax_t value = _Xp - _Yp;
+};
+
+template <intmax_t _Xp, intmax_t _Yp>
+class __ll_sub<_Xp, _Yp, 0>
+{
+public:
+    static const intmax_t value = _Xp;
+};
+
+template <intmax_t _Xp, intmax_t _Yp>
+class __ll_sub<_Xp, _Yp, -1>
+{
+    static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
+    static const intmax_t max = -min;
+
+    static_assert(_Xp <= max + _Yp, "overflow in __ll_sub");
+public:
+    static const intmax_t value = _Xp - _Yp;
+};
+
+template <intmax_t _Xp, intmax_t _Yp>
+class __ll_mul
+{
+    static const intmax_t nan = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1));
+    static const intmax_t min = nan + 1;
+    static const intmax_t max = -min;
+    static const intmax_t __a_x = __static_abs<_Xp>::value;
+    static const intmax_t __a_y = __static_abs<_Yp>::value;
+
+    static_assert(_Xp != nan && _Yp != nan && __a_x <= max / __a_y, "overflow in __ll_mul");
+public:
+    static const intmax_t value = _Xp * _Yp;
+};
+
+template <intmax_t _Yp>
+class __ll_mul<0, _Yp>
+{
+public:
+    static const intmax_t value = 0;
+};
+
+template <intmax_t _Xp>
+class __ll_mul<_Xp, 0>
+{
+public:
+    static const intmax_t value = 0;
+};
+
+template <>
+class __ll_mul<0, 0>
+{
+public:
+    static const intmax_t value = 0;
+};
+
+// Not actually used but left here in case needed in future maintenance
+template <intmax_t _Xp, intmax_t _Yp>
+class __ll_div
+{
+    static const intmax_t nan = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1));
+    static const intmax_t min = nan + 1;
+    static const intmax_t max = -min;
+
+    static_assert(_Xp != nan && _Yp != nan && _Yp != 0, "overflow in __ll_div");
+public:
+    static const intmax_t value = _Xp / _Yp;
+};
+
+template <intmax_t _Num, intmax_t _Den = 1>
+class _LIBCPP_TEMPLATE_VIS ratio
+{
+    static_assert(__static_abs<_Num>::value >= 0, "ratio numerator is out of range");
+    static_assert(_Den != 0, "ratio divide by 0");
+    static_assert(__static_abs<_Den>::value >  0, "ratio denominator is out of range");
+    static _LIBCPP_CONSTEXPR const intmax_t __na = __static_abs<_Num>::value;
+    static _LIBCPP_CONSTEXPR const intmax_t __da = __static_abs<_Den>::value;
+    static _LIBCPP_CONSTEXPR const intmax_t __s = __static_sign<_Num>::value * __static_sign<_Den>::value;
+    static _LIBCPP_CONSTEXPR const intmax_t __gcd = __static_gcd<__na, __da>::value;
+public:
+    static _LIBCPP_CONSTEXPR const intmax_t num = __s * __na / __gcd;
+    static _LIBCPP_CONSTEXPR const intmax_t den = __da / __gcd;
+
+    typedef ratio<num, den> type;
+};
+
+template <intmax_t _Num, intmax_t _Den>
+_LIBCPP_CONSTEXPR const intmax_t ratio<_Num, _Den>::num;
+
+template <intmax_t _Num, intmax_t _Den>
+_LIBCPP_CONSTEXPR const intmax_t ratio<_Num, _Den>::den;
+
+template <class _Tp>                    struct __is_ratio                     : false_type {};
+template <intmax_t _Num, intmax_t _Den> struct __is_ratio<ratio<_Num, _Den> > : true_type  {};
+
+typedef ratio<1LL, 1000000000000000000LL> atto;
+typedef ratio<1LL,    1000000000000000LL> femto;
+typedef ratio<1LL,       1000000000000LL> pico;
+typedef ratio<1LL,          1000000000LL> nano;
+typedef ratio<1LL,             1000000LL> micro;
+typedef ratio<1LL,                1000LL> milli;
+typedef ratio<1LL,                 100LL> centi;
+typedef ratio<1LL,                  10LL> deci;
+typedef ratio<                 10LL, 1LL> deca;
+typedef ratio<                100LL, 1LL> hecto;
+typedef ratio<               1000LL, 1LL> kilo;
+typedef ratio<            1000000LL, 1LL> mega;
+typedef ratio<         1000000000LL, 1LL> giga;
+typedef ratio<      1000000000000LL, 1LL> tera;
+typedef ratio<   1000000000000000LL, 1LL> peta;
+typedef ratio<1000000000000000000LL, 1LL> exa;
+
+template <class _R1, class _R2>
+struct __ratio_multiply
+{
+private:
+    static const intmax_t __gcd_n1_d2 = __static_gcd<_R1::num, _R2::den>::value;
+    static const intmax_t __gcd_d1_n2 = __static_gcd<_R1::den, _R2::num>::value;
+public:
+    typedef typename ratio
+        <
+            __ll_mul<_R1::num / __gcd_n1_d2, _R2::num / __gcd_d1_n2>::value,
+            __ll_mul<_R2::den / __gcd_n1_d2, _R1::den / __gcd_d1_n2>::value
+        >::type type;
+};
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _R1, class _R2> using ratio_multiply
+                                    = typename __ratio_multiply<_R1, _R2>::type;
+
+#else  // _LIBCPP_CXX03_LANG
+
+template <class _R1, class _R2>
+struct _LIBCPP_TEMPLATE_VIS ratio_multiply
+    : public __ratio_multiply<_R1, _R2>::type {};
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _R1, class _R2>
+struct __ratio_divide
+{
+private:
+    static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
+    static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
+public:
+    typedef typename ratio
+        <
+            __ll_mul<_R1::num / __gcd_n1_n2, _R2::den / __gcd_d1_d2>::value,
+            __ll_mul<_R2::num / __gcd_n1_n2, _R1::den / __gcd_d1_d2>::value
+        >::type type;
+};
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _R1, class _R2> using ratio_divide
+                                      = typename __ratio_divide<_R1, _R2>::type;
+
+#else  // _LIBCPP_CXX03_LANG
+
+template <class _R1, class _R2>
+struct _LIBCPP_TEMPLATE_VIS ratio_divide
+    : public __ratio_divide<_R1, _R2>::type {};
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _R1, class _R2>
+struct __ratio_add
+{
+private:
+    static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
+    static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
+public:
+    typedef typename ratio_multiply
+        <
+            ratio<__gcd_n1_n2, _R1::den / __gcd_d1_d2>,
+            ratio
+            <
+                __ll_add
+                <
+                    __ll_mul<_R1::num / __gcd_n1_n2, _R2::den / __gcd_d1_d2>::value,
+                    __ll_mul<_R2::num / __gcd_n1_n2, _R1::den / __gcd_d1_d2>::value
+                >::value,
+                _R2::den
+            >
+        >::type type;
+};
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _R1, class _R2> using ratio_add
+                                         = typename __ratio_add<_R1, _R2>::type;
+
+#else  // _LIBCPP_CXX03_LANG
+
+template <class _R1, class _R2>
+struct _LIBCPP_TEMPLATE_VIS ratio_add
+    : public __ratio_add<_R1, _R2>::type {};
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _R1, class _R2>
+struct __ratio_subtract
+{
+private:
+    static const intmax_t __gcd_n1_n2 = __static_gcd<_R1::num, _R2::num>::value;
+    static const intmax_t __gcd_d1_d2 = __static_gcd<_R1::den, _R2::den>::value;
+public:
+    typedef typename ratio_multiply
+        <
+            ratio<__gcd_n1_n2, _R1::den / __gcd_d1_d2>,
+            ratio
+            <
+                __ll_sub
+                <
+                    __ll_mul<_R1::num / __gcd_n1_n2, _R2::den / __gcd_d1_d2>::value,
+                    __ll_mul<_R2::num / __gcd_n1_n2, _R1::den / __gcd_d1_d2>::value
+                >::value,
+                _R2::den
+            >
+        >::type type;
+};
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _R1, class _R2> using ratio_subtract
+                                    = typename __ratio_subtract<_R1, _R2>::type;
+
+#else  // _LIBCPP_CXX03_LANG
+
+template <class _R1, class _R2>
+struct _LIBCPP_TEMPLATE_VIS ratio_subtract
+    : public __ratio_subtract<_R1, _R2>::type {};
+
+#endif // _LIBCPP_CXX03_LANG
+
+// ratio_equal
+
+template <class _R1, class _R2>
+struct _LIBCPP_TEMPLATE_VIS ratio_equal
+    : public _LIBCPP_BOOL_CONSTANT((_R1::num == _R2::num && _R1::den == _R2::den)) {};
+
+template <class _R1, class _R2>
+struct _LIBCPP_TEMPLATE_VIS ratio_not_equal
+    : public _LIBCPP_BOOL_CONSTANT((!ratio_equal<_R1, _R2>::value)) {};
+
+// ratio_less
+
+template <class _R1, class _R2, bool _Odd = false,
+          intmax_t _Q1 = _R1::num / _R1::den, intmax_t _M1 = _R1::num % _R1::den,
+          intmax_t _Q2 = _R2::num / _R2::den, intmax_t _M2 = _R2::num % _R2::den>
+struct __ratio_less1
+{
+    static const bool value = _Odd ? _Q2 < _Q1 : _Q1 < _Q2;
+};
+
+template <class _R1, class _R2, bool _Odd, intmax_t _Qp>
+struct __ratio_less1<_R1, _R2, _Odd, _Qp, 0, _Qp, 0>
+{
+    static const bool value = false;
+};
+
+template <class _R1, class _R2, bool _Odd, intmax_t _Qp, intmax_t _M2>
+struct __ratio_less1<_R1, _R2, _Odd, _Qp, 0, _Qp, _M2>
+{
+    static const bool value = !_Odd;
+};
+
+template <class _R1, class _R2, bool _Odd, intmax_t _Qp, intmax_t _M1>
+struct __ratio_less1<_R1, _R2, _Odd, _Qp, _M1, _Qp, 0>
+{
+    static const bool value = _Odd;
+};
+
+template <class _R1, class _R2, bool _Odd, intmax_t _Qp, intmax_t _M1,
+                                                        intmax_t _M2>
+struct __ratio_less1<_R1, _R2, _Odd, _Qp, _M1, _Qp, _M2>
+{
+    static const bool value = __ratio_less1<ratio<_R1::den, _M1>,
+                                            ratio<_R2::den, _M2>, !_Odd>::value;
+};
+
+template <class _R1, class _R2, intmax_t _S1 = __static_sign<_R1::num>::value,
+                                intmax_t _S2 = __static_sign<_R2::num>::value>
+struct __ratio_less
+{
+    static const bool value = _S1 < _S2;
+};
+
+template <class _R1, class _R2>
+struct __ratio_less<_R1, _R2, 1LL, 1LL>
+{
+    static const bool value = __ratio_less1<_R1, _R2>::value;
+};
+
+template <class _R1, class _R2>
+struct __ratio_less<_R1, _R2, -1LL, -1LL>
+{
+    static const bool value = __ratio_less1<ratio<-_R2::num, _R2::den>, ratio<-_R1::num, _R1::den> >::value;
+};
+
+template <class _R1, class _R2>
+struct _LIBCPP_TEMPLATE_VIS ratio_less
+    : public _LIBCPP_BOOL_CONSTANT((__ratio_less<_R1, _R2>::value)) {};
+
+template <class _R1, class _R2>
+struct _LIBCPP_TEMPLATE_VIS ratio_less_equal
+    : public _LIBCPP_BOOL_CONSTANT((!ratio_less<_R2, _R1>::value)) {};
+
+template <class _R1, class _R2>
+struct _LIBCPP_TEMPLATE_VIS ratio_greater
+    : public _LIBCPP_BOOL_CONSTANT((ratio_less<_R2, _R1>::value)) {};
+
+template <class _R1, class _R2>
+struct _LIBCPP_TEMPLATE_VIS ratio_greater_equal
+    : public _LIBCPP_BOOL_CONSTANT((!ratio_less<_R1, _R2>::value)) {};
+
+template <class _R1, class _R2>
+struct __ratio_gcd
+{
+    typedef ratio<__static_gcd<_R1::num, _R2::num>::value,
+                  __static_lcm<_R1::den, _R2::den>::value> type;
+};
+
+#if _LIBCPP_STD_VER > 14
+template <class _R1, class _R2>
+inline constexpr bool ratio_equal_v = ratio_equal<_R1, _R2>::value;
+
+template <class _R1, class _R2>
+inline constexpr bool ratio_not_equal_v = ratio_not_equal<_R1, _R2>::value;
+
+template <class _R1, class _R2>
+inline constexpr bool ratio_less_v = ratio_less<_R1, _R2>::value;
+
+template <class _R1, class _R2>
+inline constexpr bool ratio_less_equal_v = ratio_less_equal<_R1, _R2>::value;
+
+template <class _R1, class _R2>
+inline constexpr bool ratio_greater_v = ratio_greater<_R1, _R2>::value;
+
+template <class _R1, class _R2>
+inline constexpr bool ratio_greater_equal_v = ratio_greater_equal<_R1, _R2>::value;
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_RATIO
diff --git a/contrib/libs/cxxsupp/libcxx/include/regex b/contrib/libs/cxxsupp/libcxx/include/regex
new file mode 100644
index 00000000000..c0d1edac5ef
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/regex
@@ -0,0 +1,6801 @@
+// -*- C++ -*-
+//===--------------------------- regex ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_REGEX
+#define _LIBCPP_REGEX
+
+/*
+    regex synopsis
+
+#include <initializer_list>
+
+namespace std
+{
+
+namespace regex_constants
+{
+
+enum syntax_option_type
+{
+    icase      = unspecified,
+    nosubs     = unspecified,
+    optimize   = unspecified,
+    collate    = unspecified,
+    ECMAScript = unspecified,
+    basic      = unspecified,
+    extended   = unspecified,
+    awk        = unspecified,
+    grep       = unspecified,
+    egrep      = unspecified,
+    multiline  = unspecified
+};
+
+constexpr syntax_option_type operator~(syntax_option_type f);
+constexpr syntax_option_type operator&(syntax_option_type lhs, syntax_option_type rhs);
+constexpr syntax_option_type operator|(syntax_option_type lhs, syntax_option_type rhs);
+
+enum match_flag_type
+{
+    match_default     = 0,
+    match_not_bol     = unspecified,
+    match_not_eol     = unspecified,
+    match_not_bow     = unspecified,
+    match_not_eow     = unspecified,
+    match_any         = unspecified,
+    match_not_null    = unspecified,
+    match_continuous  = unspecified,
+    match_prev_avail  = unspecified,
+    format_default    = 0,
+    format_sed        = unspecified,
+    format_no_copy    = unspecified,
+    format_first_only = unspecified
+};
+
+constexpr match_flag_type operator~(match_flag_type f);
+constexpr match_flag_type operator&(match_flag_type lhs, match_flag_type rhs);
+constexpr match_flag_type operator|(match_flag_type lhs, match_flag_type rhs);
+
+enum error_type
+{
+    error_collate    = unspecified,
+    error_ctype      = unspecified,
+    error_escape     = unspecified,
+    error_backref    = unspecified,
+    error_brack      = unspecified,
+    error_paren      = unspecified,
+    error_brace      = unspecified,
+    error_badbrace   = unspecified,
+    error_range      = unspecified,
+    error_space      = unspecified,
+    error_badrepeat  = unspecified,
+    error_complexity = unspecified,
+    error_stack      = unspecified
+};
+
+}  // regex_constants
+
+class regex_error
+    : public runtime_error
+{
+public:
+    explicit regex_error(regex_constants::error_type ecode);
+    regex_constants::error_type code() const;
+};
+
+template <class charT>
+struct regex_traits
+{
+public:
+    typedef charT                   char_type;
+    typedef basic_string<char_type> string_type;
+    typedef locale                  locale_type;
+    typedef /bitmask_type/          char_class_type;
+
+    regex_traits();
+
+    static size_t length(const char_type* p);
+    charT translate(charT c) const;
+    charT translate_nocase(charT c) const;
+    template <class ForwardIterator>
+        string_type
+        transform(ForwardIterator first, ForwardIterator last) const;
+    template <class ForwardIterator>
+        string_type
+        transform_primary( ForwardIterator first, ForwardIterator last) const;
+    template <class ForwardIterator>
+        string_type
+        lookup_collatename(ForwardIterator first, ForwardIterator last) const;
+    template <class ForwardIterator>
+        char_class_type
+        lookup_classname(ForwardIterator first, ForwardIterator last,
+                         bool icase = false) const;
+    bool isctype(charT c, char_class_type f) const;
+    int value(charT ch, int radix) const;
+    locale_type imbue(locale_type l);
+    locale_type getloc()const;
+};
+
+template <class charT, class traits = regex_traits<charT>>
+class basic_regex
+{
+public:
+    // types:
+    typedef charT                               value_type;
+    typedef traits                              traits_type;
+    typedef typename traits::string_type        string_type;
+    typedef regex_constants::syntax_option_type flag_type;
+    typedef typename traits::locale_type        locale_type;
+
+    // constants:
+    static constexpr regex_constants::syntax_option_type icase = regex_constants::icase;
+    static constexpr regex_constants::syntax_option_type nosubs = regex_constants::nosubs;
+    static constexpr regex_constants::syntax_option_type optimize = regex_constants::optimize;
+    static constexpr regex_constants::syntax_option_type collate = regex_constants::collate;
+    static constexpr regex_constants::syntax_option_type ECMAScript = regex_constants::ECMAScript;
+    static constexpr regex_constants::syntax_option_type basic = regex_constants::basic;
+    static constexpr regex_constants::syntax_option_type extended = regex_constants::extended;
+    static constexpr regex_constants::syntax_option_type awk = regex_constants::awk;
+    static constexpr regex_constants::syntax_option_type grep = regex_constants::grep;
+    static constexpr regex_constants::syntax_option_type egrep = regex_constants::egrep;
+    static constexpr regex_constants::syntax_option_type multiline = regex_constants::multiline;
+
+    // construct/copy/destroy:
+    basic_regex();
+    explicit basic_regex(const charT* p, flag_type f = regex_constants::ECMAScript);
+    basic_regex(const charT* p, size_t len, flag_type f = regex_constants::ECMAScript);
+    basic_regex(const basic_regex&);
+    basic_regex(basic_regex&&) noexcept;
+    template <class ST, class SA>
+        explicit basic_regex(const basic_string<charT, ST, SA>& p,
+                             flag_type f = regex_constants::ECMAScript);
+    template <class ForwardIterator>
+        basic_regex(ForwardIterator first, ForwardIterator last,
+                    flag_type f = regex_constants::ECMAScript);
+    basic_regex(initializer_list<charT>, flag_type = regex_constants::ECMAScript);
+
+    ~basic_regex();
+
+    basic_regex& operator=(const basic_regex&);
+    basic_regex& operator=(basic_regex&&) noexcept;
+    basic_regex& operator=(const charT* ptr);
+    basic_regex& operator=(initializer_list<charT> il);
+    template <class ST, class SA>
+        basic_regex& operator=(const basic_string<charT, ST, SA>& p);
+
+    // assign:
+    basic_regex& assign(const basic_regex& that);
+    basic_regex& assign(basic_regex&& that) noexcept;
+    basic_regex& assign(const charT* ptr,           flag_type f = regex_constants::ECMAScript);
+    basic_regex& assign(const charT* p, size_t len, flag_type f = regex_constants::ECMAScript);
+    template <class string_traits, class A>
+        basic_regex& assign(const basic_string<charT, string_traits, A>& s,
+                                                    flag_type f = regex_constants::ECMAScript);
+    template <class InputIterator>
+        basic_regex& assign(InputIterator first, InputIterator last,
+                                                    flag_type f = regex_constants::ECMAScript);
+    basic_regex& assign(initializer_list<charT>,    flag_type f = regex_constants::ECMAScript);
+
+    // const operations:
+    unsigned mark_count() const;
+    flag_type flags() const;
+
+    // locale:
+    locale_type imbue(locale_type loc);
+    locale_type getloc() const;
+
+    // swap:
+    void swap(basic_regex&);
+};
+
+template<class ForwardIterator>
+basic_regex(ForwardIterator, ForwardIterator,
+            regex_constants::syntax_option_type = regex_constants::ECMAScript)
+    -> basic_regex<typename iterator_traits<ForwardIterator>::value_type>; // C++17
+
+typedef basic_regex<char>    regex;
+typedef basic_regex<wchar_t> wregex;
+
+template <class charT, class traits>
+    void swap(basic_regex<charT, traits>& e1, basic_regex<charT, traits>& e2);
+
+template <class BidirectionalIterator>
+class sub_match
+    : public pair<BidirectionalIterator, BidirectionalIterator>
+{
+public:
+    typedef typename iterator_traits<BidirectionalIterator>::value_type value_type;
+    typedef typename iterator_traits<BidirectionalIterator>::difference_type difference_type;
+    typedef BidirectionalIterator                                      iterator;
+    typedef basic_string<value_type>                                string_type;
+
+    bool matched;
+
+    constexpr sub_match();
+
+    difference_type length() const;
+    operator string_type() const;
+    string_type str() const;
+
+    int compare(const sub_match& s) const;
+    int compare(const string_type& s) const;
+    int compare(const value_type* s) const;
+};
+
+typedef sub_match<const char*>             csub_match;
+typedef sub_match<const wchar_t*>          wcsub_match;
+typedef sub_match<string::const_iterator>  ssub_match;
+typedef sub_match<wstring::const_iterator> wssub_match;
+
+template <class BiIter>
+    bool
+    operator==(const sub_match<BiIter>& lhs, const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator!=(const sub_match<BiIter>& lhs, const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator<(const sub_match<BiIter>& lhs, const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator<=(const sub_match<BiIter>& lhs, const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator>=(const sub_match<BiIter>& lhs, const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator>(const sub_match<BiIter>& lhs, const sub_match<BiIter>& rhs);
+
+template <class BiIter, class ST, class SA>
+    bool
+    operator==(const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+               const sub_match<BiIter>& rhs);
+
+template <class BiIter, class ST, class SA>
+    bool
+    operator!=(const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+               const sub_match<BiIter>& rhs);
+
+template <class BiIter, class ST, class SA>
+    bool
+    operator<(const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+              const sub_match<BiIter>& rhs);
+
+template <class BiIter, class ST, class SA>
+    bool
+    operator>(const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+              const sub_match<BiIter>& rhs);
+
+template <class BiIter, class ST, class SA>
+    bool operator>=(const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+                    const sub_match<BiIter>& rhs);
+
+template <class BiIter, class ST, class SA>
+    bool
+    operator<=(const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& lhs,
+               const sub_match<BiIter>& rhs);
+
+template <class BiIter, class ST, class SA>
+    bool
+    operator==(const sub_match<BiIter>& lhs,
+               const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
+template <class BiIter, class ST, class SA>
+    bool
+    operator!=(const sub_match<BiIter>& lhs,
+               const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
+template <class BiIter, class ST, class SA>
+    bool
+    operator<(const sub_match<BiIter>& lhs,
+              const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
+template <class BiIter, class ST, class SA>
+    bool operator>(const sub_match<BiIter>& lhs,
+                   const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
+template <class BiIter, class ST, class SA>
+    bool
+    operator>=(const sub_match<BiIter>& lhs,
+               const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
+template <class BiIter, class ST, class SA>
+    bool
+    operator<=(const sub_match<BiIter>& lhs,
+               const basic_string<typename iterator_traits<BiIter>::value_type, ST, SA>& rhs);
+
+template <class BiIter>
+    bool
+    operator==(typename iterator_traits<BiIter>::value_type const* lhs,
+               const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator!=(typename iterator_traits<BiIter>::value_type const* lhs,
+               const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator<(typename iterator_traits<BiIter>::value_type const* lhs,
+              const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator>(typename iterator_traits<BiIter>::value_type const* lhs,
+              const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator>=(typename iterator_traits<BiIter>::value_type const* lhs,
+               const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator<=(typename iterator_traits<BiIter>::value_type const* lhs,
+               const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator==(const sub_match<BiIter>& lhs,
+               typename iterator_traits<BiIter>::value_type const* rhs);
+
+template <class BiIter>
+    bool
+    operator!=(const sub_match<BiIter>& lhs,
+               typename iterator_traits<BiIter>::value_type const* rhs);
+
+template <class BiIter>
+    bool
+    operator<(const sub_match<BiIter>& lhs,
+              typename iterator_traits<BiIter>::value_type const* rhs);
+
+template <class BiIter>
+    bool
+    operator>(const sub_match<BiIter>& lhs,
+              typename iterator_traits<BiIter>::value_type const* rhs);
+
+template <class BiIter>
+    bool
+    operator>=(const sub_match<BiIter>& lhs,
+               typename iterator_traits<BiIter>::value_type const* rhs);
+
+template <class BiIter>
+    bool
+    operator<=(const sub_match<BiIter>& lhs,
+               typename iterator_traits<BiIter>::value_type const* rhs);
+
+template <class BiIter>
+    bool
+    operator==(typename iterator_traits<BiIter>::value_type const& lhs,
+               const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator!=(typename iterator_traits<BiIter>::value_type const& lhs,
+               const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator<(typename iterator_traits<BiIter>::value_type const& lhs,
+              const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator>(typename iterator_traits<BiIter>::value_type const& lhs,
+              const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator>=(typename iterator_traits<BiIter>::value_type const& lhs,
+               const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator<=(typename iterator_traits<BiIter>::value_type const& lhs,
+               const sub_match<BiIter>& rhs);
+
+template <class BiIter>
+    bool
+    operator==(const sub_match<BiIter>& lhs,
+               typename iterator_traits<BiIter>::value_type const& rhs);
+
+template <class BiIter>
+    bool
+    operator!=(const sub_match<BiIter>& lhs,
+               typename iterator_traits<BiIter>::value_type const& rhs);
+
+template <class BiIter>
+    bool
+    operator<(const sub_match<BiIter>& lhs,
+              typename iterator_traits<BiIter>::value_type const& rhs);
+
+template <class BiIter>
+    bool
+    operator>(const sub_match<BiIter>& lhs,
+              typename iterator_traits<BiIter>::value_type const& rhs);
+
+template <class BiIter>
+    bool
+    operator>=(const sub_match<BiIter>& lhs,
+               typename iterator_traits<BiIter>::value_type const& rhs);
+
+template <class BiIter>
+    bool
+    operator<=(const sub_match<BiIter>& lhs,
+               typename iterator_traits<BiIter>::value_type const& rhs);
+
+template <class charT, class ST, class BiIter>
+    basic_ostream<charT, ST>&
+    operator<<(basic_ostream<charT, ST>& os, const sub_match<BiIter>& m);
+
+template <class BidirectionalIterator,
+          class Allocator = allocator<sub_match<BidirectionalIterator>>>
+class match_results
+{
+public:
+    typedef sub_match<BidirectionalIterator>                  value_type;
+    typedef const value_type&                                 const_reference;
+    typedef value_type&                                       reference;
+    typedef /implementation-defined/                          const_iterator;
+    typedef const_iterator                                    iterator;
+    typedef typename iterator_traits<BidirectionalIterator>::difference_type difference_type;
+    typedef typename allocator_traits<Allocator>::size_type   size_type;
+    typedef Allocator                                         allocator_type;
+    typedef typename iterator_traits<BidirectionalIterator>::value_type char_type;
+    typedef basic_string<char_type>                           string_type;
+
+    // construct/copy/destroy:
+    explicit match_results(const Allocator& a = Allocator()); // before C++20
+    match_results() : match_results(Allocator()) {}           // C++20
+    explicit match_results(const Allocator& a);               // C++20
+    match_results(const match_results& m);
+    match_results(match_results&& m) noexcept;
+    match_results& operator=(const match_results& m);
+    match_results& operator=(match_results&& m);
+    ~match_results();
+
+    bool ready() const;
+
+    // size:
+    size_type size() const;
+    size_type max_size() const;
+    bool empty() const;
+
+    // element access:
+    difference_type length(size_type sub = 0) const;
+    difference_type position(size_type sub = 0) const;
+    string_type str(size_type sub = 0) const;
+    const_reference operator[](size_type n) const;
+
+    const_reference prefix() const;
+    const_reference suffix() const;
+
+    const_iterator begin() const;
+    const_iterator end() const;
+    const_iterator cbegin() const;
+    const_iterator cend() const;
+
+    // format:
+    template <class OutputIter>
+        OutputIter
+        format(OutputIter out, const char_type* fmt_first,
+               const char_type* fmt_last,
+               regex_constants::match_flag_type flags = regex_constants::format_default) const;
+    template <class OutputIter, class ST, class SA>
+        OutputIter
+        format(OutputIter out, const basic_string<char_type, ST, SA>& fmt,
+               regex_constants::match_flag_type flags = regex_constants::format_default) const;
+    template <class ST, class SA>
+        basic_string<char_type, ST, SA>
+        format(const basic_string<char_type, ST, SA>& fmt,
+               regex_constants::match_flag_type flags = regex_constants::format_default) const;
+    string_type
+        format(const char_type* fmt,
+               regex_constants::match_flag_type flags = regex_constants::format_default) const;
+
+    // allocator:
+    allocator_type get_allocator() const;
+
+    // swap:
+    void swap(match_results& that);
+};
+
+typedef match_results<const char*>             cmatch;
+typedef match_results<const wchar_t*>          wcmatch;
+typedef match_results<string::const_iterator>  smatch;
+typedef match_results<wstring::const_iterator> wsmatch;
+
+template <class BidirectionalIterator, class Allocator>
+    bool
+    operator==(const match_results<BidirectionalIterator, Allocator>& m1,
+               const match_results<BidirectionalIterator, Allocator>& m2);
+
+template <class BidirectionalIterator, class Allocator>
+    bool
+    operator!=(const match_results<BidirectionalIterator, Allocator>& m1,
+               const match_results<BidirectionalIterator, Allocator>& m2);
+
+template <class BidirectionalIterator, class Allocator>
+    void
+    swap(match_results<BidirectionalIterator, Allocator>& m1,
+         match_results<BidirectionalIterator, Allocator>& m2);
+
+template <class BidirectionalIterator, class Allocator, class charT, class traits>
+    bool
+    regex_match(BidirectionalIterator first, BidirectionalIterator last,
+                match_results<BidirectionalIterator, Allocator>& m,
+                const basic_regex<charT, traits>& e,
+                regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class BidirectionalIterator, class charT, class traits>
+    bool
+    regex_match(BidirectionalIterator first, BidirectionalIterator last,
+                const basic_regex<charT, traits>& e,
+                regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class charT, class Allocator, class traits>
+    bool
+    regex_match(const charT* str, match_results<const charT*, Allocator>& m,
+                const basic_regex<charT, traits>& e,
+                regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class ST, class SA, class Allocator, class charT, class traits>
+    bool
+    regex_match(const basic_string<charT, ST, SA>& s,
+                match_results<typename basic_string<charT, ST, SA>::const_iterator, Allocator>& m,
+                const basic_regex<charT, traits>& e,
+                regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class ST, class SA, class Allocator, class charT, class traits>
+    bool
+    regex_match(const basic_string<charT, ST, SA>&& s,
+                match_results<typename basic_string<charT, ST, SA>::const_iterator, Allocator>& m,
+                const basic_regex<charT, traits>& e,
+                regex_constants::match_flag_type flags = regex_constants::match_default) = delete; // C++14
+
+template <class charT, class traits>
+    bool
+    regex_match(const charT* str, const basic_regex<charT, traits>& e,
+                regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class ST, class SA, class charT, class traits>
+    bool
+    regex_match(const basic_string<charT, ST, SA>& s,
+                const basic_regex<charT, traits>& e,
+                regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class BidirectionalIterator, class Allocator, class charT, class traits>
+    bool
+    regex_search(BidirectionalIterator first, BidirectionalIterator last,
+                 match_results<BidirectionalIterator, Allocator>& m,
+                 const basic_regex<charT, traits>& e,
+                 regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class BidirectionalIterator, class charT, class traits>
+    bool
+    regex_search(BidirectionalIterator first, BidirectionalIterator last,
+                 const basic_regex<charT, traits>& e,
+                 regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class charT, class Allocator, class traits>
+    bool
+    regex_search(const charT* str, match_results<const charT*, Allocator>& m,
+                 const basic_regex<charT, traits>& e,
+                 regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class charT, class traits>
+    bool
+    regex_search(const charT* str, const basic_regex<charT, traits>& e,
+                 regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class ST, class SA, class charT, class traits>
+    bool
+    regex_search(const basic_string<charT, ST, SA>& s,
+                 const basic_regex<charT, traits>& e,
+                 regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class ST, class SA, class Allocator, class charT, class traits>
+    bool
+    regex_search(const basic_string<charT, ST, SA>& s,
+                 match_results<typename basic_string<charT, ST, SA>::const_iterator, Allocator>& m,
+                 const basic_regex<charT, traits>& e,
+                 regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class ST, class SA, class Allocator, class charT, class traits>
+    bool
+    regex_search(const basic_string<charT, ST, SA>&& s,
+                 match_results<typename basic_string<charT, ST, SA>::const_iterator, Allocator>& m,
+                 const basic_regex<charT, traits>& e,
+                 regex_constants::match_flag_type flags = regex_constants::match_default) = delete; // C++14
+
+template <class OutputIterator, class BidirectionalIterator,
+          class traits, class charT, class ST, class SA>
+    OutputIterator
+    regex_replace(OutputIterator out,
+                  BidirectionalIterator first, BidirectionalIterator last,
+                  const basic_regex<charT, traits>& e,
+                  const basic_string<charT, ST, SA>& fmt,
+                  regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class OutputIterator, class BidirectionalIterator,
+          class traits, class charT>
+    OutputIterator
+    regex_replace(OutputIterator out,
+                  BidirectionalIterator first, BidirectionalIterator last,
+                  const basic_regex<charT, traits>& e, const charT* fmt,
+                  regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class traits, class charT, class ST, class SA, class FST, class FSA>
+    basic_string<charT, ST, SA>
+    regex_replace(const basic_string<charT, ST, SA>& s,
+                  const basic_regex<charT, traits>& e,
+                  const basic_string<charT, FST, FSA>& fmt,
+                  regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class traits, class charT, class ST, class SA>
+    basic_string<charT, ST, SA>
+    regex_replace(const basic_string<charT, ST, SA>& s,
+                  const basic_regex<charT, traits>& e, const charT* fmt,
+                  regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class traits, class charT, class ST, class SA>
+    basic_string<charT>
+    regex_replace(const charT* s,
+                  const basic_regex<charT, traits>& e,
+                  const basic_string<charT, ST, SA>& fmt,
+                  regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class traits, class charT>
+    basic_string<charT>
+    regex_replace(const charT* s,
+                  const basic_regex<charT, traits>& e,
+                  const charT* fmt,
+                  regex_constants::match_flag_type flags = regex_constants::match_default);
+
+template <class BidirectionalIterator,
+          class charT = typename iterator_traits< BidirectionalIterator>::value_type,
+          class traits = regex_traits<charT>>
+class regex_iterator
+{
+public:
+    typedef basic_regex<charT, traits>           regex_type;
+    typedef match_results<BidirectionalIterator> value_type;
+    typedef ptrdiff_t                            difference_type;
+    typedef const value_type*                    pointer;
+    typedef const value_type&                    reference;
+    typedef forward_iterator_tag                 iterator_category;
+
+    regex_iterator();
+    regex_iterator(BidirectionalIterator a, BidirectionalIterator b,
+                   const regex_type& re,
+                   regex_constants::match_flag_type m = regex_constants::match_default);
+    regex_iterator(BidirectionalIterator a, BidirectionalIterator b,
+                   const regex_type&& re,
+                   regex_constants::match_flag_type m
+                                     = regex_constants::match_default) = delete; // C++14
+    regex_iterator(const regex_iterator&);
+    regex_iterator& operator=(const regex_iterator&);
+
+    bool operator==(const regex_iterator&) const;
+    bool operator!=(const regex_iterator&) const;
+
+    const value_type& operator*() const;
+    const value_type* operator->() const;
+
+    regex_iterator& operator++();
+    regex_iterator operator++(int);
+};
+
+typedef regex_iterator<const char*>             cregex_iterator;
+typedef regex_iterator<const wchar_t*>          wcregex_iterator;
+typedef regex_iterator<string::const_iterator>  sregex_iterator;
+typedef regex_iterator<wstring::const_iterator> wsregex_iterator;
+
+template <class BidirectionalIterator,
+          class charT = typename iterator_traits<BidirectionalIterator>::value_type,
+          class traits = regex_traits<charT>>
+class regex_token_iterator
+{
+public:
+    typedef basic_regex<charT, traits>       regex_type;
+    typedef sub_match<BidirectionalIterator> value_type;
+    typedef ptrdiff_t                        difference_type;
+    typedef const value_type*                pointer;
+    typedef const value_type&                reference;
+    typedef forward_iterator_tag             iterator_category;
+
+    regex_token_iterator();
+    regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
+                         const regex_type& re, int submatch = 0,
+                         regex_constants::match_flag_type m = regex_constants::match_default);
+    regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
+                         const regex_type&& re, int submatch = 0,
+                         regex_constants::match_flag_type m = regex_constants::match_default) = delete; // C++14
+    regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
+                         const regex_type& re, const vector<int>& submatches,
+                         regex_constants::match_flag_type m = regex_constants::match_default);
+    regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
+                         const regex_type&& re, const vector<int>& submatches,
+                         regex_constants::match_flag_type m = regex_constants::match_default) = delete; // C++14
+    regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
+                         const regex_type& re, initializer_list<int> submatches,
+                         regex_constants::match_flag_type m = regex_constants::match_default);
+    regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
+                         const regex_type&& re, initializer_list<int> submatches,
+                         regex_constants::match_flag_type m = regex_constants::match_default) = delete; // C++14
+    template <size_t N>
+        regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
+                             const regex_type& re, const int (&submatches)[N],
+                             regex_constants::match_flag_type m = regex_constants::match_default);
+    template <size_t N>
+        regex_token_iterator(BidirectionalIterator a, BidirectionalIterator b,
+                             const regex_type&& re, const int (&submatches)[N],
+                             regex_constants::match_flag_type m = regex_constants::match_default) = delete; // C++14
+    regex_token_iterator(const regex_token_iterator&);
+    regex_token_iterator& operator=(const regex_token_iterator&);
+
+    bool operator==(const regex_token_iterator&) const;
+    bool operator!=(const regex_token_iterator&) const;
+
+    const value_type& operator*() const;
+    const value_type* operator->() const;
+
+    regex_token_iterator& operator++();
+    regex_token_iterator operator++(int);
+};
+
+typedef regex_token_iterator<const char*>             cregex_token_iterator;
+typedef regex_token_iterator<const wchar_t*>          wcregex_token_iterator;
+typedef regex_token_iterator<string::const_iterator>  sregex_token_iterator;
+typedef regex_token_iterator<wstring::const_iterator> wsregex_token_iterator;
+
+} // std
+*/
+
+#include <__config>
+#include <__debug>
+#include <__iterator/wrap_iter.h>
+#include <__locale>
+#include <compare>
+#include <deque>
+#include <initializer_list>
+#include <iterator>
+#include <memory>
+#include <stdexcept>
+#include <string>
+#include <utility>
+#include <vector>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+#define _LIBCPP_REGEX_COMPLEXITY_FACTOR 4096
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace regex_constants
+{
+
+// syntax_option_type
+
+enum syntax_option_type
+{
+    icase      = 1 << 0,
+    nosubs     = 1 << 1,
+    optimize   = 1 << 2,
+    collate    = 1 << 3,
+#ifdef _LIBCPP_ABI_REGEX_CONSTANTS_NONZERO
+    ECMAScript = 1 << 9,
+#else
+    ECMAScript = 0,
+#endif
+    basic      = 1 << 4,
+    extended   = 1 << 5,
+    awk        = 1 << 6,
+    grep       = 1 << 7,
+    egrep      = 1 << 8,
+    // 1 << 9 may be used by ECMAScript
+    multiline  = 1 << 10
+};
+
+inline _LIBCPP_CONSTEXPR
+syntax_option_type __get_grammar(syntax_option_type __g)
+{
+#ifdef _LIBCPP_ABI_REGEX_CONSTANTS_NONZERO
+    return static_cast<syntax_option_type>(__g & 0x3F0);
+#else
+    return static_cast<syntax_option_type>(__g & 0x1F0);
+#endif
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+syntax_option_type
+operator~(syntax_option_type __x)
+{
+    return syntax_option_type(~int(__x) & 0x1FF);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+syntax_option_type
+operator&(syntax_option_type __x, syntax_option_type __y)
+{
+    return syntax_option_type(int(__x) & int(__y));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+syntax_option_type
+operator|(syntax_option_type __x, syntax_option_type __y)
+{
+    return syntax_option_type(int(__x) | int(__y));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+syntax_option_type
+operator^(syntax_option_type __x, syntax_option_type __y)
+{
+    return syntax_option_type(int(__x) ^ int(__y));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+syntax_option_type&
+operator&=(syntax_option_type& __x, syntax_option_type __y)
+{
+    __x = __x & __y;
+    return __x;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+syntax_option_type&
+operator|=(syntax_option_type& __x, syntax_option_type __y)
+{
+    __x = __x | __y;
+    return __x;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+syntax_option_type&
+operator^=(syntax_option_type& __x, syntax_option_type __y)
+{
+    __x = __x ^ __y;
+    return __x;
+}
+
+// match_flag_type
+
+enum match_flag_type
+{
+    match_default     = 0,
+    match_not_bol     = 1 << 0,
+    match_not_eol     = 1 << 1,
+    match_not_bow     = 1 << 2,
+    match_not_eow     = 1 << 3,
+    match_any         = 1 << 4,
+    match_not_null    = 1 << 5,
+    match_continuous  = 1 << 6,
+    match_prev_avail  = 1 << 7,
+    format_default    = 0,
+    format_sed        = 1 << 8,
+    format_no_copy    = 1 << 9,
+    format_first_only = 1 << 10,
+    __no_update_pos   = 1 << 11,
+    __full_match      = 1 << 12
+};
+
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+match_flag_type
+operator~(match_flag_type __x)
+{
+    return match_flag_type(~int(__x) & 0x0FFF);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+match_flag_type
+operator&(match_flag_type __x, match_flag_type __y)
+{
+    return match_flag_type(int(__x) & int(__y));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+match_flag_type
+operator|(match_flag_type __x, match_flag_type __y)
+{
+    return match_flag_type(int(__x) | int(__y));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR
+match_flag_type
+operator^(match_flag_type __x, match_flag_type __y)
+{
+    return match_flag_type(int(__x) ^ int(__y));
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+match_flag_type&
+operator&=(match_flag_type& __x, match_flag_type __y)
+{
+    __x = __x & __y;
+    return __x;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+match_flag_type&
+operator|=(match_flag_type& __x, match_flag_type __y)
+{
+    __x = __x | __y;
+    return __x;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+match_flag_type&
+operator^=(match_flag_type& __x, match_flag_type __y)
+{
+    __x = __x ^ __y;
+    return __x;
+}
+
+enum error_type
+{
+    error_collate = 1,
+    error_ctype,
+    error_escape,
+    error_backref,
+    error_brack,
+    error_paren,
+    error_brace,
+    error_badbrace,
+    error_range,
+    error_space,
+    error_badrepeat,
+    error_complexity,
+    error_stack,
+    __re_err_grammar,
+    __re_err_empty,
+    __re_err_unknown,
+    __re_err_parse
+};
+
+}  // regex_constants
+
+class _LIBCPP_EXCEPTION_ABI regex_error
+    : public runtime_error
+{
+    regex_constants::error_type __code_;
+public:
+    explicit regex_error(regex_constants::error_type __ecode);
+    regex_error(const regex_error&) _NOEXCEPT = default;
+    virtual ~regex_error() _NOEXCEPT;
+     _LIBCPP_INLINE_VISIBILITY
+    regex_constants::error_type code() const {return __code_;}
+};
+
+template <regex_constants::error_type _Ev>
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+void __throw_regex_error()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw regex_error(_Ev);
+#else
+    _VSTD::abort();
+#endif
+}
+
+template <class _CharT>
+struct _LIBCPP_TEMPLATE_VIS regex_traits
+{
+public:
+    typedef _CharT                  char_type;
+    typedef basic_string<char_type> string_type;
+    typedef locale                  locale_type;
+#ifdef __BIONIC__
+    // Originally bionic's ctype_base used its own ctype masks because the
+    // builtin ctype implementation wasn't in libc++ yet. Bionic's ctype mask
+    // was only 8 bits wide and already saturated, so it used a wider type here
+    // to make room for __regex_word (then a part of this class rather than
+    // ctype_base). Bionic has since moved to the builtin ctype_base
+    // implementation, but this was not updated to match. Since then Android has
+    // needed to maintain a stable libc++ ABI, and this can't be changed without
+    // an ABI break.
+    typedef uint16_t char_class_type;
+#else
+    typedef ctype_base::mask        char_class_type;
+#endif
+
+    static const char_class_type __regex_word = ctype_base::__regex_word;
+private:
+    locale __loc_;
+    const ctype<char_type>* __ct_;
+    const collate<char_type>* __col_;
+
+public:
+    regex_traits();
+
+    _LIBCPP_INLINE_VISIBILITY
+    static size_t length(const char_type* __p)
+        {return char_traits<char_type>::length(__p);}
+    _LIBCPP_INLINE_VISIBILITY
+    char_type translate(char_type __c) const {return __c;}
+    char_type translate_nocase(char_type __c) const;
+    template <class _ForwardIterator>
+        string_type
+        transform(_ForwardIterator __f, _ForwardIterator __l) const;
+    template <class _ForwardIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        string_type
+        transform_primary( _ForwardIterator __f, _ForwardIterator __l) const
+            {return __transform_primary(__f, __l, char_type());}
+    template <class _ForwardIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        string_type
+        lookup_collatename(_ForwardIterator __f, _ForwardIterator __l) const
+            {return __lookup_collatename(__f, __l, char_type());}
+    template <class _ForwardIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        char_class_type
+        lookup_classname(_ForwardIterator __f, _ForwardIterator __l,
+                         bool __icase = false) const
+            {return __lookup_classname(__f, __l, __icase, char_type());}
+    bool isctype(char_type __c, char_class_type __m) const;
+    _LIBCPP_INLINE_VISIBILITY
+    int value(char_type __ch, int __radix) const
+        {return __regex_traits_value(__ch, __radix);}
+    locale_type imbue(locale_type __l);
+    _LIBCPP_INLINE_VISIBILITY
+    locale_type getloc()const {return __loc_;}
+
+private:
+    void __init();
+
+    template <class _ForwardIterator>
+        string_type
+        __transform_primary(_ForwardIterator __f, _ForwardIterator __l, char) const;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    template <class _ForwardIterator>
+        string_type
+        __transform_primary(_ForwardIterator __f, _ForwardIterator __l, wchar_t) const;
+#endif
+    template <class _ForwardIterator>
+        string_type
+        __lookup_collatename(_ForwardIterator __f, _ForwardIterator __l, char) const;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    template <class _ForwardIterator>
+        string_type
+        __lookup_collatename(_ForwardIterator __f, _ForwardIterator __l, wchar_t) const;
+#endif
+    template <class _ForwardIterator>
+        char_class_type
+        __lookup_classname(_ForwardIterator __f, _ForwardIterator __l,
+                           bool __icase, char) const;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    template <class _ForwardIterator>
+        char_class_type
+        __lookup_classname(_ForwardIterator __f, _ForwardIterator __l,
+                           bool __icase, wchar_t) const;
+#endif
+
+    static int __regex_traits_value(unsigned char __ch, int __radix);
+    _LIBCPP_INLINE_VISIBILITY
+    int __regex_traits_value(char __ch, int __radix) const
+        {return __regex_traits_value(static_cast<unsigned char>(__ch), __radix);}
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    _LIBCPP_INLINE_VISIBILITY
+    int __regex_traits_value(wchar_t __ch, int __radix) const;
+#endif
+};
+
+template <class _CharT>
+const typename regex_traits<_CharT>::char_class_type
+regex_traits<_CharT>::__regex_word;
+
+template <class _CharT>
+regex_traits<_CharT>::regex_traits()
+{
+    __init();
+}
+
+template <class _CharT>
+typename regex_traits<_CharT>::char_type
+regex_traits<_CharT>::translate_nocase(char_type __c) const
+{
+    return __ct_->tolower(__c);
+}
+
+template <class _CharT>
+template <class _ForwardIterator>
+typename regex_traits<_CharT>::string_type
+regex_traits<_CharT>::transform(_ForwardIterator __f, _ForwardIterator __l) const
+{
+    string_type __s(__f, __l);
+    return __col_->transform(__s.data(), __s.data() + __s.size());
+}
+
+template <class _CharT>
+void
+regex_traits<_CharT>::__init()
+{
+    __ct_ = &use_facet<ctype<char_type> >(__loc_);
+    __col_ = &use_facet<collate<char_type> >(__loc_);
+}
+
+template <class _CharT>
+typename regex_traits<_CharT>::locale_type
+regex_traits<_CharT>::imbue(locale_type __l)
+{
+    locale __r = __loc_;
+    __loc_ = __l;
+    __init();
+    return __r;
+}
+
+// transform_primary is very FreeBSD-specific
+
+template <class _CharT>
+template <class _ForwardIterator>
+typename regex_traits<_CharT>::string_type
+regex_traits<_CharT>::__transform_primary(_ForwardIterator __f,
+                                          _ForwardIterator __l, char) const
+{
+    const string_type __s(__f, __l);
+    string_type __d = __col_->transform(__s.data(), __s.data() + __s.size());
+    switch (__d.size())
+    {
+    case 1:
+        break;
+    case 12:
+        __d[11] = __d[3];
+        break;
+    default:
+        __d.clear();
+        break;
+    }
+    return __d;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <class _CharT>
+template <class _ForwardIterator>
+typename regex_traits<_CharT>::string_type
+regex_traits<_CharT>::__transform_primary(_ForwardIterator __f,
+                                          _ForwardIterator __l, wchar_t) const
+{
+    const string_type __s(__f, __l);
+    string_type __d = __col_->transform(__s.data(), __s.data() + __s.size());
+    switch (__d.size())
+    {
+    case 1:
+        break;
+    case 3:
+        __d[2] = __d[0];
+        break;
+    default:
+        __d.clear();
+        break;
+    }
+    return __d;
+}
+#endif
+
+// lookup_collatename is very FreeBSD-specific
+
+_LIBCPP_FUNC_VIS string __get_collation_name(const char* __s);
+
+template <class _CharT>
+template <class _ForwardIterator>
+typename regex_traits<_CharT>::string_type
+regex_traits<_CharT>::__lookup_collatename(_ForwardIterator __f,
+                                           _ForwardIterator __l, char) const
+{
+    string_type __s(__f, __l);
+    string_type __r;
+    if (!__s.empty())
+    {
+        __r = __get_collation_name(__s.c_str());
+        if (__r.empty() && __s.size() <= 2)
+        {
+            __r = __col_->transform(__s.data(), __s.data() + __s.size());
+            if (__r.size() == 1 || __r.size() == 12)
+                __r = __s;
+            else
+                __r.clear();
+        }
+    }
+    return __r;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <class _CharT>
+template <class _ForwardIterator>
+typename regex_traits<_CharT>::string_type
+regex_traits<_CharT>::__lookup_collatename(_ForwardIterator __f,
+                                           _ForwardIterator __l, wchar_t) const
+{
+    string_type __s(__f, __l);
+    string __n;
+    __n.reserve(__s.size());
+    for (typename string_type::const_iterator __i = __s.begin(), __e = __s.end();
+                                                              __i != __e; ++__i)
+    {
+        if (static_cast<unsigned>(*__i) >= 127)
+            return string_type();
+        __n.push_back(char(*__i));
+    }
+    string_type __r;
+    if (!__s.empty())
+    {
+        __n = __get_collation_name(__n.c_str());
+        if (!__n.empty())
+            __r.assign(__n.begin(), __n.end());
+        else if (__s.size() <= 2)
+        {
+            __r = __col_->transform(__s.data(), __s.data() + __s.size());
+            if (__r.size() == 1 || __r.size() == 3)
+                __r = __s;
+            else
+                __r.clear();
+        }
+    }
+    return __r;
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// lookup_classname
+
+regex_traits<char>::char_class_type _LIBCPP_FUNC_VIS
+__get_classname(const char* __s, bool __icase);
+
+template <class _CharT>
+template <class _ForwardIterator>
+typename regex_traits<_CharT>::char_class_type
+regex_traits<_CharT>::__lookup_classname(_ForwardIterator __f,
+                                         _ForwardIterator __l,
+                                         bool __icase, char) const
+{
+    string_type __s(__f, __l);
+    __ct_->tolower(&__s[0], &__s[0] + __s.size());
+    return __get_classname(__s.c_str(), __icase);
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <class _CharT>
+template <class _ForwardIterator>
+typename regex_traits<_CharT>::char_class_type
+regex_traits<_CharT>::__lookup_classname(_ForwardIterator __f,
+                                         _ForwardIterator __l,
+                                         bool __icase, wchar_t) const
+{
+    string_type __s(__f, __l);
+    __ct_->tolower(&__s[0], &__s[0] + __s.size());
+    string __n;
+    __n.reserve(__s.size());
+    for (typename string_type::const_iterator __i = __s.begin(), __e = __s.end();
+                                                              __i != __e; ++__i)
+    {
+        if (static_cast<unsigned>(*__i) >= 127)
+            return char_class_type();
+        __n.push_back(char(*__i));
+    }
+    return __get_classname(__n.c_str(), __icase);
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+template <class _CharT>
+bool
+regex_traits<_CharT>::isctype(char_type __c, char_class_type __m) const
+{
+    if (__ct_->is(__m, __c))
+        return true;
+    return (__c == '_' && (__m & __regex_word));
+}
+
+template <class _CharT>
+int
+regex_traits<_CharT>::__regex_traits_value(unsigned char __ch, int __radix)
+{
+    if ((__ch & 0xF8u) == 0x30)  // '0' <= __ch && __ch <= '7'
+        return __ch - '0';
+    if (__radix != 8)
+    {
+        if ((__ch & 0xFEu) == 0x38)  // '8' <= __ch && __ch <= '9'
+            return __ch - '0';
+        if (__radix == 16)
+        {
+            __ch |= 0x20;  // tolower
+            if ('a' <= __ch && __ch <= 'f')
+                return __ch - ('a' - 10);
+        }
+    }
+    return -1;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <class _CharT>
+inline
+int
+regex_traits<_CharT>::__regex_traits_value(wchar_t __ch, int __radix) const
+{
+    return __regex_traits_value(static_cast<unsigned char>(__ct_->narrow(__ch, char_type())), __radix);
+}
+#endif
+
+template <class _CharT> class __node;
+
+template <class _BidirectionalIterator> class _LIBCPP_TEMPLATE_VIS sub_match;
+
+template <class _BidirectionalIterator,
+          class _Allocator = allocator<sub_match<_BidirectionalIterator> > >
+class _LIBCPP_TEMPLATE_VIS match_results;
+
+template <class _CharT>
+struct __state
+{
+    enum
+    {
+        __end_state = -1000,
+        __consume_input,  // -999
+        __begin_marked_expr, // -998
+        __end_marked_expr,   // -997
+        __pop_state,           // -996
+        __accept_and_consume,  // -995
+        __accept_but_not_consume,  // -994
+        __reject,                  // -993
+        __split,
+        __repeat
+    };
+
+    int __do_;
+    const _CharT* __first_;
+    const _CharT* __current_;
+    const _CharT* __last_;
+    vector<sub_match<const _CharT*> > __sub_matches_;
+    vector<pair<size_t, const _CharT*> > __loop_data_;
+    const __node<_CharT>* __node_;
+    regex_constants::match_flag_type __flags_;
+    bool __at_first_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __state()
+        : __do_(0), __first_(nullptr), __current_(nullptr), __last_(nullptr),
+          __node_(nullptr), __flags_() {}
+};
+
+// __node
+
+template <class _CharT>
+class __node
+{
+    __node(const __node&);
+    __node& operator=(const __node&);
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __node() {}
+    _LIBCPP_INLINE_VISIBILITY
+    virtual ~__node() {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    virtual void __exec(__state&) const {}
+    _LIBCPP_INLINE_VISIBILITY
+    virtual void __exec_split(bool, __state&) const {}
+};
+
+// __end_state
+
+template <class _CharT>
+class __end_state
+    : public __node<_CharT>
+{
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __end_state() {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT>
+void
+__end_state<_CharT>::__exec(__state& __s) const
+{
+    __s.__do_ = __state::__end_state;
+}
+
+// __has_one_state
+
+template <class _CharT>
+class __has_one_state
+    : public __node<_CharT>
+{
+    __node<_CharT>* __first_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __has_one_state(__node<_CharT>* __s)
+        : __first_(__s) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __node<_CharT>*  first() const {return __first_;}
+    _LIBCPP_INLINE_VISIBILITY
+    __node<_CharT>*& first()       {return __first_;}
+};
+
+// __owns_one_state
+
+template <class _CharT>
+class __owns_one_state
+    : public __has_one_state<_CharT>
+{
+    typedef __has_one_state<_CharT> base;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __owns_one_state(__node<_CharT>* __s)
+        : base(__s) {}
+
+    virtual ~__owns_one_state();
+};
+
+template <class _CharT>
+__owns_one_state<_CharT>::~__owns_one_state()
+{
+    delete this->first();
+}
+
+// __empty_state
+
+template <class _CharT>
+class __empty_state
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __empty_state(__node<_CharT>* __s)
+        : base(__s) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT>
+void
+__empty_state<_CharT>::__exec(__state& __s) const
+{
+    __s.__do_ = __state::__accept_but_not_consume;
+    __s.__node_ = this->first();
+}
+
+// __empty_non_own_state
+
+template <class _CharT>
+class __empty_non_own_state
+    : public __has_one_state<_CharT>
+{
+    typedef __has_one_state<_CharT> base;
+
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __empty_non_own_state(__node<_CharT>* __s)
+        : base(__s) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT>
+void
+__empty_non_own_state<_CharT>::__exec(__state& __s) const
+{
+    __s.__do_ = __state::__accept_but_not_consume;
+    __s.__node_ = this->first();
+}
+
+// __repeat_one_loop
+
+template <class _CharT>
+class __repeat_one_loop
+    : public __has_one_state<_CharT>
+{
+    typedef __has_one_state<_CharT> base;
+
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __repeat_one_loop(__node<_CharT>* __s)
+        : base(__s) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT>
+void
+__repeat_one_loop<_CharT>::__exec(__state& __s) const
+{
+    __s.__do_ = __state::__repeat;
+    __s.__node_ = this->first();
+}
+
+// __owns_two_states
+
+template <class _CharT>
+class __owns_two_states
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+    base* __second_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __owns_two_states(__node<_CharT>* __s1, base* __s2)
+        : base(__s1), __second_(__s2) {}
+
+    virtual ~__owns_two_states();
+
+    _LIBCPP_INLINE_VISIBILITY
+    base*  second() const {return __second_;}
+    _LIBCPP_INLINE_VISIBILITY
+    base*& second()       {return __second_;}
+};
+
+template <class _CharT>
+__owns_two_states<_CharT>::~__owns_two_states()
+{
+    delete __second_;
+}
+
+// __loop
+
+template <class _CharT>
+class __loop
+    : public __owns_two_states<_CharT>
+{
+    typedef __owns_two_states<_CharT> base;
+
+    size_t __min_;
+    size_t __max_;
+    unsigned __loop_id_;
+    unsigned __mexp_begin_;
+    unsigned __mexp_end_;
+    bool __greedy_;
+
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __loop(unsigned __loop_id,
+                          __node<_CharT>* __s1, __owns_one_state<_CharT>* __s2,
+                          unsigned __mexp_begin, unsigned __mexp_end,
+                          bool __greedy = true,
+                          size_t __min = 0,
+                          size_t __max = numeric_limits<size_t>::max())
+        : base(__s1, __s2), __min_(__min), __max_(__max), __loop_id_(__loop_id),
+          __mexp_begin_(__mexp_begin), __mexp_end_(__mexp_end),
+          __greedy_(__greedy) {}
+
+    virtual void __exec(__state& __s) const;
+    virtual void __exec_split(bool __second, __state& __s) const;
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    void __init_repeat(__state& __s) const
+    {
+        __s.__loop_data_[__loop_id_].second = __s.__current_;
+        for (size_t __i = __mexp_begin_-1; __i != __mexp_end_-1; ++__i)
+        {
+            __s.__sub_matches_[__i].first = __s.__last_;
+            __s.__sub_matches_[__i].second = __s.__last_;
+            __s.__sub_matches_[__i].matched = false;
+        }
+    }
+};
+
+template <class _CharT>
+void
+__loop<_CharT>::__exec(__state& __s) const
+{
+    if (__s.__do_ == __state::__repeat)
+    {
+        bool __do_repeat = ++__s.__loop_data_[__loop_id_].first < __max_;
+        bool __do_alt = __s.__loop_data_[__loop_id_].first >= __min_;
+        if (__do_repeat && __do_alt &&
+                               __s.__loop_data_[__loop_id_].second == __s.__current_)
+            __do_repeat = false;
+        if (__do_repeat && __do_alt)
+            __s.__do_ = __state::__split;
+        else if (__do_repeat)
+        {
+            __s.__do_ = __state::__accept_but_not_consume;
+            __s.__node_ = this->first();
+            __init_repeat(__s);
+        }
+        else
+        {
+            __s.__do_ = __state::__accept_but_not_consume;
+            __s.__node_ = this->second();
+        }
+    }
+    else
+    {
+        __s.__loop_data_[__loop_id_].first = 0;
+        bool __do_repeat = 0 < __max_;
+        bool __do_alt = 0 >= __min_;
+        if (__do_repeat && __do_alt)
+            __s.__do_ = __state::__split;
+        else if (__do_repeat)
+        {
+            __s.__do_ = __state::__accept_but_not_consume;
+            __s.__node_ = this->first();
+            __init_repeat(__s);
+        }
+        else
+        {
+            __s.__do_ = __state::__accept_but_not_consume;
+            __s.__node_ = this->second();
+        }
+    }
+}
+
+template <class _CharT>
+void
+__loop<_CharT>::__exec_split(bool __second, __state& __s) const
+{
+    __s.__do_ = __state::__accept_but_not_consume;
+    if (__greedy_ != __second)
+    {
+        __s.__node_ = this->first();
+        __init_repeat(__s);
+    }
+    else
+        __s.__node_ = this->second();
+}
+
+// __alternate
+
+template <class _CharT>
+class __alternate
+    : public __owns_two_states<_CharT>
+{
+    typedef __owns_two_states<_CharT> base;
+
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __alternate(__owns_one_state<_CharT>* __s1,
+                         __owns_one_state<_CharT>* __s2)
+        : base(__s1, __s2) {}
+
+    virtual void __exec(__state& __s) const;
+    virtual void __exec_split(bool __second, __state& __s) const;
+};
+
+template <class _CharT>
+void
+__alternate<_CharT>::__exec(__state& __s) const
+{
+    __s.__do_ = __state::__split;
+}
+
+template <class _CharT>
+void
+__alternate<_CharT>::__exec_split(bool __second, __state& __s) const
+{
+    __s.__do_ = __state::__accept_but_not_consume;
+    if (__second)
+        __s.__node_ = this->second();
+    else
+        __s.__node_ = this->first();
+}
+
+// __begin_marked_subexpression
+
+template <class _CharT>
+class __begin_marked_subexpression
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+    unsigned __mexp_;
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __begin_marked_subexpression(unsigned __mexp, __node<_CharT>* __s)
+        : base(__s), __mexp_(__mexp) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT>
+void
+__begin_marked_subexpression<_CharT>::__exec(__state& __s) const
+{
+    __s.__do_ = __state::__accept_but_not_consume;
+    __s.__sub_matches_[__mexp_-1].first = __s.__current_;
+    __s.__node_ = this->first();
+}
+
+// __end_marked_subexpression
+
+template <class _CharT>
+class __end_marked_subexpression
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+    unsigned __mexp_;
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __end_marked_subexpression(unsigned __mexp, __node<_CharT>* __s)
+        : base(__s), __mexp_(__mexp) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT>
+void
+__end_marked_subexpression<_CharT>::__exec(__state& __s) const
+{
+    __s.__do_ = __state::__accept_but_not_consume;
+    __s.__sub_matches_[__mexp_-1].second = __s.__current_;
+    __s.__sub_matches_[__mexp_-1].matched = true;
+    __s.__node_ = this->first();
+}
+
+// __back_ref
+
+template <class _CharT>
+class __back_ref
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+    unsigned __mexp_;
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __back_ref(unsigned __mexp, __node<_CharT>* __s)
+        : base(__s), __mexp_(__mexp) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT>
+void
+__back_ref<_CharT>::__exec(__state& __s) const
+{
+    if (__mexp_ > __s.__sub_matches_.size())
+        __throw_regex_error<regex_constants::error_backref>();
+    sub_match<const _CharT*>& __sm = __s.__sub_matches_[__mexp_-1];
+    if (__sm.matched)
+    {
+        ptrdiff_t __len = __sm.second - __sm.first;
+        if (__s.__last_ - __s.__current_ >= __len &&
+            _VSTD::equal(__sm.first, __sm.second, __s.__current_))
+        {
+            __s.__do_ = __state::__accept_but_not_consume;
+            __s.__current_ += __len;
+            __s.__node_ = this->first();
+        }
+        else
+        {
+            __s.__do_ = __state::__reject;
+            __s.__node_ = nullptr;
+        }
+    }
+    else
+    {
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+// __back_ref_icase
+
+template <class _CharT, class _Traits>
+class __back_ref_icase
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+    _Traits __traits_;
+    unsigned __mexp_;
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __back_ref_icase(const _Traits& __traits, unsigned __mexp,
+                              __node<_CharT>* __s)
+        : base(__s), __traits_(__traits), __mexp_(__mexp) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT, class _Traits>
+void
+__back_ref_icase<_CharT, _Traits>::__exec(__state& __s) const
+{
+    sub_match<const _CharT*>& __sm = __s.__sub_matches_[__mexp_-1];
+    if (__sm.matched)
+    {
+        ptrdiff_t __len = __sm.second - __sm.first;
+        if (__s.__last_ - __s.__current_ >= __len)
+        {
+            for (ptrdiff_t __i = 0; __i < __len; ++__i)
+            {
+                if (__traits_.translate_nocase(__sm.first[__i]) !=
+                                __traits_.translate_nocase(__s.__current_[__i]))
+                    goto __not_equal;
+            }
+            __s.__do_ = __state::__accept_but_not_consume;
+            __s.__current_ += __len;
+            __s.__node_ = this->first();
+        }
+        else
+        {
+            __s.__do_ = __state::__reject;
+            __s.__node_ = nullptr;
+        }
+    }
+    else
+    {
+__not_equal:
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+// __back_ref_collate
+
+template <class _CharT, class _Traits>
+class __back_ref_collate
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+    _Traits __traits_;
+    unsigned __mexp_;
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __back_ref_collate(const _Traits& __traits, unsigned __mexp,
+                              __node<_CharT>* __s)
+        : base(__s), __traits_(__traits), __mexp_(__mexp) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT, class _Traits>
+void
+__back_ref_collate<_CharT, _Traits>::__exec(__state& __s) const
+{
+    sub_match<const _CharT*>& __sm = __s.__sub_matches_[__mexp_-1];
+    if (__sm.matched)
+    {
+        ptrdiff_t __len = __sm.second - __sm.first;
+        if (__s.__last_ - __s.__current_ >= __len)
+        {
+            for (ptrdiff_t __i = 0; __i < __len; ++__i)
+            {
+                if (__traits_.translate(__sm.first[__i]) !=
+                                       __traits_.translate(__s.__current_[__i]))
+                    goto __not_equal;
+            }
+            __s.__do_ = __state::__accept_but_not_consume;
+            __s.__current_ += __len;
+            __s.__node_ = this->first();
+        }
+        else
+        {
+            __s.__do_ = __state::__reject;
+            __s.__node_ = nullptr;
+        }
+    }
+    else
+    {
+__not_equal:
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+// __word_boundary
+
+template <class _CharT, class _Traits>
+class __word_boundary
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+    _Traits __traits_;
+    bool __invert_;
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __word_boundary(const _Traits& __traits, bool __invert,
+                             __node<_CharT>* __s)
+        : base(__s), __traits_(__traits), __invert_(__invert) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT, class _Traits>
+void
+__word_boundary<_CharT, _Traits>::__exec(__state& __s) const
+{
+    bool __is_word_b = false;
+    if (__s.__first_ != __s.__last_)
+    {
+        if (__s.__current_ == __s.__last_)
+        {
+            if (!(__s.__flags_ & regex_constants::match_not_eow))
+            {
+                _CharT __c = __s.__current_[-1];
+                __is_word_b = __c == '_' ||
+                              __traits_.isctype(__c, ctype_base::alnum);
+            }
+        }
+        else if (__s.__current_ == __s.__first_ &&
+                !(__s.__flags_ & regex_constants::match_prev_avail))
+        {
+            if (!(__s.__flags_ & regex_constants::match_not_bow))
+            {
+                _CharT __c = *__s.__current_;
+                __is_word_b = __c == '_' ||
+                              __traits_.isctype(__c, ctype_base::alnum);
+            }
+        }
+        else
+        {
+            _CharT __c1 = __s.__current_[-1];
+            _CharT __c2 = *__s.__current_;
+            bool __is_c1_b = __c1 == '_' ||
+                             __traits_.isctype(__c1, ctype_base::alnum);
+            bool __is_c2_b = __c2 == '_' ||
+                             __traits_.isctype(__c2, ctype_base::alnum);
+            __is_word_b = __is_c1_b != __is_c2_b;
+        }
+    }
+    if (__is_word_b != __invert_)
+    {
+        __s.__do_ = __state::__accept_but_not_consume;
+        __s.__node_ = this->first();
+    }
+    else
+    {
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+// __l_anchor
+
+template <class _CharT>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+bool __is_eol(_CharT c)
+{
+    return c == '\r' || c == '\n';
+}
+
+template <class _CharT>
+class __l_anchor_multiline
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+    bool __multiline_;
+
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __l_anchor_multiline(bool __multiline, __node<_CharT>* __s)
+        : base(__s), __multiline_(__multiline) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT>
+void
+__l_anchor_multiline<_CharT>::__exec(__state& __s) const
+{
+    if (__s.__at_first_ && __s.__current_ == __s.__first_ &&
+        !(__s.__flags_ & regex_constants::match_not_bol))
+    {
+        __s.__do_ = __state::__accept_but_not_consume;
+        __s.__node_ = this->first();
+    }
+    else if (__multiline_ &&
+             !__s.__at_first_ &&
+             __is_eol(*_VSTD::prev(__s.__current_)))
+    {
+        __s.__do_ = __state::__accept_but_not_consume;
+        __s.__node_ = this->first();
+    }
+    else
+    {
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+// __r_anchor
+
+template <class _CharT>
+class __r_anchor_multiline
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+    bool __multiline;
+
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __r_anchor_multiline(bool __multiline, __node<_CharT>* __s)
+        : base(__s), __multiline(__multiline) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT>
+void
+__r_anchor_multiline<_CharT>::__exec(__state& __s) const
+{
+    if (__s.__current_ == __s.__last_ &&
+        !(__s.__flags_ & regex_constants::match_not_eol))
+    {
+        __s.__do_ = __state::__accept_but_not_consume;
+        __s.__node_ = this->first();
+    }
+    else if (__multiline && __is_eol(*__s.__current_))
+    {
+        __s.__do_ = __state::__accept_but_not_consume;
+        __s.__node_ = this->first();
+    }
+    else
+    {
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+// __match_any
+
+template <class _CharT>
+class __match_any
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __match_any(__node<_CharT>* __s)
+        : base(__s) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT>
+void
+__match_any<_CharT>::__exec(__state& __s) const
+{
+    if (__s.__current_ != __s.__last_ && *__s.__current_ != 0)
+    {
+        __s.__do_ = __state::__accept_and_consume;
+        ++__s.__current_;
+        __s.__node_ = this->first();
+    }
+    else
+    {
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+// __match_any_but_newline
+
+template <class _CharT>
+class __match_any_but_newline
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __match_any_but_newline(__node<_CharT>* __s)
+        : base(__s) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <> _LIBCPP_FUNC_VIS void __match_any_but_newline<char>::__exec(__state&) const;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <> _LIBCPP_FUNC_VIS void __match_any_but_newline<wchar_t>::__exec(__state&) const;
+#endif
+
+// __match_char
+
+template <class _CharT>
+class __match_char
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+    _CharT __c_;
+
+    __match_char(const __match_char&);
+    __match_char& operator=(const __match_char&);
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __match_char(_CharT __c, __node<_CharT>* __s)
+        : base(__s), __c_(__c) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT>
+void
+__match_char<_CharT>::__exec(__state& __s) const
+{
+    if (__s.__current_ != __s.__last_ && *__s.__current_ == __c_)
+    {
+        __s.__do_ = __state::__accept_and_consume;
+        ++__s.__current_;
+        __s.__node_ = this->first();
+    }
+    else
+    {
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+// __match_char_icase
+
+template <class _CharT, class _Traits>
+class __match_char_icase
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+    _Traits __traits_;
+    _CharT __c_;
+
+    __match_char_icase(const __match_char_icase&);
+    __match_char_icase& operator=(const __match_char_icase&);
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __match_char_icase(const _Traits& __traits, _CharT __c, __node<_CharT>* __s)
+        : base(__s), __traits_(__traits), __c_(__traits.translate_nocase(__c)) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT, class _Traits>
+void
+__match_char_icase<_CharT, _Traits>::__exec(__state& __s) const
+{
+    if (__s.__current_ != __s.__last_ &&
+        __traits_.translate_nocase(*__s.__current_) == __c_)
+    {
+        __s.__do_ = __state::__accept_and_consume;
+        ++__s.__current_;
+        __s.__node_ = this->first();
+    }
+    else
+    {
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+// __match_char_collate
+
+template <class _CharT, class _Traits>
+class __match_char_collate
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+    _Traits __traits_;
+    _CharT __c_;
+
+    __match_char_collate(const __match_char_collate&);
+    __match_char_collate& operator=(const __match_char_collate&);
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __match_char_collate(const _Traits& __traits, _CharT __c, __node<_CharT>* __s)
+        : base(__s), __traits_(__traits), __c_(__traits.translate(__c)) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT, class _Traits>
+void
+__match_char_collate<_CharT, _Traits>::__exec(__state& __s) const
+{
+    if (__s.__current_ != __s.__last_ &&
+        __traits_.translate(*__s.__current_) == __c_)
+    {
+        __s.__do_ = __state::__accept_and_consume;
+        ++__s.__current_;
+        __s.__node_ = this->first();
+    }
+    else
+    {
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+// __bracket_expression
+
+template <class _CharT, class _Traits>
+class __bracket_expression
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+    typedef typename _Traits::string_type string_type;
+
+    _Traits __traits_;
+    vector<_CharT> __chars_;
+    vector<_CharT> __neg_chars_;
+    vector<pair<string_type, string_type> > __ranges_;
+    vector<pair<_CharT, _CharT> > __digraphs_;
+    vector<string_type> __equivalences_;
+    typename regex_traits<_CharT>::char_class_type __mask_;
+    typename regex_traits<_CharT>::char_class_type __neg_mask_;
+    bool __negate_;
+    bool __icase_;
+    bool __collate_;
+    bool __might_have_digraph_;
+
+    __bracket_expression(const __bracket_expression&);
+    __bracket_expression& operator=(const __bracket_expression&);
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __bracket_expression(const _Traits& __traits, __node<_CharT>* __s,
+                                 bool __negate, bool __icase, bool __collate)
+        : base(__s), __traits_(__traits), __mask_(), __neg_mask_(),
+          __negate_(__negate), __icase_(__icase), __collate_(__collate),
+          __might_have_digraph_(__traits_.getloc().name() != "C") {}
+
+    virtual void __exec(__state&) const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool __negated() const {return __negate_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __add_char(_CharT __c)
+        {
+            if (__icase_)
+                __chars_.push_back(__traits_.translate_nocase(__c));
+            else if (__collate_)
+                __chars_.push_back(__traits_.translate(__c));
+            else
+                __chars_.push_back(__c);
+        }
+    _LIBCPP_INLINE_VISIBILITY
+    void __add_neg_char(_CharT __c)
+        {
+            if (__icase_)
+                __neg_chars_.push_back(__traits_.translate_nocase(__c));
+            else if (__collate_)
+                __neg_chars_.push_back(__traits_.translate(__c));
+            else
+                __neg_chars_.push_back(__c);
+        }
+    _LIBCPP_INLINE_VISIBILITY
+    void __add_range(string_type __b, string_type __e)
+        {
+            if (__collate_)
+            {
+                if (__icase_)
+                {
+                    for (size_t __i = 0; __i < __b.size(); ++__i)
+                        __b[__i] = __traits_.translate_nocase(__b[__i]);
+                    for (size_t __i = 0; __i < __e.size(); ++__i)
+                        __e[__i] = __traits_.translate_nocase(__e[__i]);
+                }
+                else
+                {
+                    for (size_t __i = 0; __i < __b.size(); ++__i)
+                        __b[__i] = __traits_.translate(__b[__i]);
+                    for (size_t __i = 0; __i < __e.size(); ++__i)
+                        __e[__i] = __traits_.translate(__e[__i]);
+                }
+                __ranges_.push_back(make_pair(
+                                  __traits_.transform(__b.begin(), __b.end()),
+                                  __traits_.transform(__e.begin(), __e.end())));
+            }
+            else
+            {
+                if (__b.size() != 1 || __e.size() != 1)
+                    __throw_regex_error<regex_constants::error_range>();
+                if (__icase_)
+                {
+                    __b[0] = __traits_.translate_nocase(__b[0]);
+                    __e[0] = __traits_.translate_nocase(__e[0]);
+                }
+                __ranges_.push_back(make_pair(_VSTD::move(__b), _VSTD::move(__e)));
+            }
+        }
+    _LIBCPP_INLINE_VISIBILITY
+    void __add_digraph(_CharT __c1, _CharT __c2)
+        {
+            if (__icase_)
+                __digraphs_.push_back(make_pair(__traits_.translate_nocase(__c1),
+                                                __traits_.translate_nocase(__c2)));
+            else if (__collate_)
+                __digraphs_.push_back(make_pair(__traits_.translate(__c1),
+                                                __traits_.translate(__c2)));
+            else
+                __digraphs_.push_back(make_pair(__c1, __c2));
+        }
+    _LIBCPP_INLINE_VISIBILITY
+    void __add_equivalence(const string_type& __s)
+        {__equivalences_.push_back(__s);}
+    _LIBCPP_INLINE_VISIBILITY
+    void __add_class(typename regex_traits<_CharT>::char_class_type __mask)
+        {__mask_ |= __mask;}
+    _LIBCPP_INLINE_VISIBILITY
+    void __add_neg_class(typename regex_traits<_CharT>::char_class_type __mask)
+        {__neg_mask_ |= __mask;}
+};
+
+template <class _CharT, class _Traits>
+void
+__bracket_expression<_CharT, _Traits>::__exec(__state& __s) const
+{
+    bool __found = false;
+    unsigned __consumed = 0;
+    if (__s.__current_ != __s.__last_)
+    {
+        ++__consumed;
+        if (__might_have_digraph_)
+        {
+            const _CharT* __next = _VSTD::next(__s.__current_);
+            if (__next != __s.__last_)
+            {
+                pair<_CharT, _CharT> __ch2(*__s.__current_, *__next);
+                if (__icase_)
+                {
+                    __ch2.first = __traits_.translate_nocase(__ch2.first);
+                    __ch2.second = __traits_.translate_nocase(__ch2.second);
+                }
+                else if (__collate_)
+                {
+                    __ch2.first = __traits_.translate(__ch2.first);
+                    __ch2.second = __traits_.translate(__ch2.second);
+                }
+                if (!__traits_.lookup_collatename(&__ch2.first, &__ch2.first+2).empty())
+                {
+                    // __ch2 is a digraph in this locale
+                    ++__consumed;
+                    for (size_t __i = 0; __i < __digraphs_.size(); ++__i)
+                    {
+                        if (__ch2 == __digraphs_[__i])
+                        {
+                            __found = true;
+                            goto __exit;
+                        }
+                    }
+                    if (__collate_ && !__ranges_.empty())
+                    {
+                        string_type __s2 = __traits_.transform(&__ch2.first,
+                                                               &__ch2.first + 2);
+                        for (size_t __i = 0; __i < __ranges_.size(); ++__i)
+                        {
+                            if (__ranges_[__i].first <= __s2 &&
+                                __s2 <= __ranges_[__i].second)
+                            {
+                                __found = true;
+                                goto __exit;
+                            }
+                        }
+                    }
+                    if (!__equivalences_.empty())
+                    {
+                        string_type __s2 = __traits_.transform_primary(&__ch2.first,
+                                                                       &__ch2.first + 2);
+                        for (size_t __i = 0; __i < __equivalences_.size(); ++__i)
+                        {
+                            if (__s2 == __equivalences_[__i])
+                            {
+                                __found = true;
+                                goto __exit;
+                            }
+                        }
+                    }
+                    if (__traits_.isctype(__ch2.first, __mask_) &&
+                        __traits_.isctype(__ch2.second, __mask_))
+                    {
+                        __found = true;
+                        goto __exit;
+                    }
+                    if (!__traits_.isctype(__ch2.first, __neg_mask_) &&
+                        !__traits_.isctype(__ch2.second, __neg_mask_))
+                    {
+                        __found = true;
+                        goto __exit;
+                    }
+                    goto __exit;
+                }
+            }
+        }
+        // test *__s.__current_ as not a digraph
+        _CharT __ch = *__s.__current_;
+        if (__icase_)
+            __ch = __traits_.translate_nocase(__ch);
+        else if (__collate_)
+            __ch = __traits_.translate(__ch);
+        for (size_t __i = 0; __i < __chars_.size(); ++__i)
+        {
+            if (__ch == __chars_[__i])
+            {
+                __found = true;
+                goto __exit;
+            }
+        }
+        // When there's at least one of __neg_chars_ and __neg_mask_, the set
+        // of "__found" chars is
+        //   union(complement(union(__neg_chars_, __neg_mask_)),
+        //         other cases...)
+        //
+        // It doesn't make sense to check this when there are no __neg_chars_
+        // and no __neg_mask_.
+        if (!(__neg_mask_ == 0 && __neg_chars_.empty()))
+        {
+            const bool __in_neg_mask = __traits_.isctype(__ch, __neg_mask_);
+          const bool __in_neg_chars =
+              _VSTD::find(__neg_chars_.begin(), __neg_chars_.end(), __ch) !=
+              __neg_chars_.end();
+          if (!(__in_neg_mask || __in_neg_chars))
+          {
+            __found = true;
+            goto __exit;
+          }
+        }
+        if (!__ranges_.empty())
+        {
+            string_type __s2 = __collate_ ?
+                                   __traits_.transform(&__ch, &__ch + 1) :
+                                   string_type(1, __ch);
+            for (size_t __i = 0; __i < __ranges_.size(); ++__i)
+            {
+                if (__ranges_[__i].first <= __s2 && __s2 <= __ranges_[__i].second)
+                {
+                    __found = true;
+                    goto __exit;
+                }
+            }
+        }
+        if (!__equivalences_.empty())
+        {
+            string_type __s2 = __traits_.transform_primary(&__ch, &__ch + 1);
+            for (size_t __i = 0; __i < __equivalences_.size(); ++__i)
+            {
+                if (__s2 == __equivalences_[__i])
+                {
+                    __found = true;
+                    goto __exit;
+                }
+            }
+        }
+        if (__traits_.isctype(__ch, __mask_))
+        {
+            __found = true;
+            goto __exit;
+        }
+    }
+    else
+        __found = __negate_;  // force reject
+__exit:
+    if (__found != __negate_)
+    {
+        __s.__do_ = __state::__accept_and_consume;
+        __s.__current_ += __consumed;
+        __s.__node_ = this->first();
+    }
+    else
+    {
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+template <class _CharT, class _Traits> class __lookahead;
+
+template <class _CharT, class _Traits = regex_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_regex;
+
+typedef basic_regex<char>    regex;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef basic_regex<wchar_t> wregex;
+#endif
+
+template <class _CharT, class _Traits>
+class
+    _LIBCPP_TEMPLATE_VIS
+    _LIBCPP_PREFERRED_NAME(regex)
+    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wregex))
+    basic_regex
+{
+public:
+    // types:
+    typedef _CharT                              value_type;
+    typedef _Traits                             traits_type;
+    typedef typename _Traits::string_type       string_type;
+    typedef regex_constants::syntax_option_type flag_type;
+    typedef typename _Traits::locale_type       locale_type;
+
+private:
+    _Traits   __traits_;
+    flag_type __flags_;
+    unsigned __marked_count_;
+    unsigned __loop_count_;
+    int __open_count_;
+    shared_ptr<__empty_state<_CharT> > __start_;
+    __owns_one_state<_CharT>* __end_;
+
+    typedef _VSTD::__state<_CharT> __state;
+    typedef _VSTD::__node<_CharT> __node;
+
+public:
+    // constants:
+    static const regex_constants::syntax_option_type icase = regex_constants::icase;
+    static const regex_constants::syntax_option_type nosubs = regex_constants::nosubs;
+    static const regex_constants::syntax_option_type optimize = regex_constants::optimize;
+    static const regex_constants::syntax_option_type collate = regex_constants::collate;
+    static const regex_constants::syntax_option_type ECMAScript = regex_constants::ECMAScript;
+    static const regex_constants::syntax_option_type basic = regex_constants::basic;
+    static const regex_constants::syntax_option_type extended = regex_constants::extended;
+    static const regex_constants::syntax_option_type awk = regex_constants::awk;
+    static const regex_constants::syntax_option_type grep = regex_constants::grep;
+    static const regex_constants::syntax_option_type egrep = regex_constants::egrep;
+    static const regex_constants::syntax_option_type multiline = regex_constants::multiline;
+
+    // construct/copy/destroy:
+    _LIBCPP_INLINE_VISIBILITY
+    basic_regex()
+        : __flags_(regex_constants::ECMAScript), __marked_count_(0), __loop_count_(0), __open_count_(0),
+          __end_(nullptr)
+        {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_regex(const value_type* __p, flag_type __f = regex_constants::ECMAScript)
+        : __flags_(__f), __marked_count_(0), __loop_count_(0), __open_count_(0),
+          __end_(nullptr)
+        {
+        __init(__p, __p + __traits_.length(__p));
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_regex(const value_type* __p, size_t __len, flag_type __f = regex_constants::ECMAScript)
+        : __flags_(__f), __marked_count_(0), __loop_count_(0), __open_count_(0),
+          __end_(nullptr)
+        {
+        __init(__p, __p + __len);
+        }
+
+//     basic_regex(const basic_regex&) = default;
+//     basic_regex(basic_regex&&) = default;
+    template <class _ST, class _SA>
+        _LIBCPP_INLINE_VISIBILITY
+        explicit basic_regex(const basic_string<value_type, _ST, _SA>& __p,
+                             flag_type __f = regex_constants::ECMAScript)
+        : __flags_(__f), __marked_count_(0), __loop_count_(0), __open_count_(0),
+          __end_(nullptr)
+        {
+        __init(__p.begin(), __p.end());
+        }
+
+    template <class _ForwardIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        basic_regex(_ForwardIterator __first, _ForwardIterator __last,
+                    flag_type __f = regex_constants::ECMAScript)
+        : __flags_(__f), __marked_count_(0), __loop_count_(0), __open_count_(0),
+          __end_(nullptr)
+        {
+        __init(__first, __last);
+        }
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    basic_regex(initializer_list<value_type> __il,
+                flag_type __f = regex_constants::ECMAScript)
+        : __flags_(__f), __marked_count_(0), __loop_count_(0), __open_count_(0),
+          __end_(nullptr)
+        {
+        __init(__il.begin(), __il.end());
+        }
+#endif // _LIBCPP_CXX03_LANG
+
+//    ~basic_regex() = default;
+
+//     basic_regex& operator=(const basic_regex&) = default;
+//     basic_regex& operator=(basic_regex&&) = default;
+    _LIBCPP_INLINE_VISIBILITY
+    basic_regex& operator=(const value_type* __p)
+        {return assign(__p);}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    basic_regex& operator=(initializer_list<value_type> __il)
+        {return assign(__il);}
+#endif // _LIBCPP_CXX03_LANG
+    template <class _ST, class _SA>
+        _LIBCPP_INLINE_VISIBILITY
+        basic_regex& operator=(const basic_string<value_type, _ST, _SA>& __p)
+        {return assign(__p);}
+
+    // assign:
+    _LIBCPP_INLINE_VISIBILITY
+    basic_regex& assign(const basic_regex& __that)
+        {return *this = __that;}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    basic_regex& assign(basic_regex&& __that) _NOEXCEPT
+        {return *this = _VSTD::move(__that);}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    basic_regex& assign(const value_type* __p, flag_type __f = regex_constants::ECMAScript)
+        {return assign(__p, __p + __traits_.length(__p), __f);}
+    _LIBCPP_INLINE_VISIBILITY
+    basic_regex& assign(const value_type* __p, size_t __len, flag_type __f = regex_constants::ECMAScript)
+        {return assign(__p, __p + __len, __f);}
+    template <class _ST, class _SA>
+        _LIBCPP_INLINE_VISIBILITY
+        basic_regex& assign(const basic_string<value_type, _ST, _SA>& __s,
+                            flag_type __f = regex_constants::ECMAScript)
+            {return assign(__s.begin(), __s.end(), __f);}
+
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+             __is_cpp17_input_iterator  <_InputIterator>::value &&
+            !__is_cpp17_forward_iterator<_InputIterator>::value,
+            basic_regex&
+        >::type
+        assign(_InputIterator __first, _InputIterator __last,
+                            flag_type __f = regex_constants::ECMAScript)
+        {
+            basic_string<_CharT> __t(__first, __last);
+            return assign(__t.begin(), __t.end(), __f);
+        }
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    void __member_init(flag_type __f)
+    {
+        __flags_ = __f;
+        __marked_count_ = 0;
+        __loop_count_ = 0;
+        __open_count_ = 0;
+        __end_ = nullptr;
+    }
+public:
+
+    template <class _ForwardIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            __is_cpp17_forward_iterator<_ForwardIterator>::value,
+            basic_regex&
+        >::type
+        assign(_ForwardIterator __first, _ForwardIterator __last,
+                            flag_type __f = regex_constants::ECMAScript)
+        {
+            return assign(basic_regex(__first, __last, __f));
+        }
+
+#ifndef _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_regex& assign(initializer_list<value_type> __il,
+                        flag_type __f = regex_constants::ECMAScript)
+        {return assign(__il.begin(), __il.end(), __f);}
+
+#endif // _LIBCPP_CXX03_LANG
+
+    // const operations:
+    _LIBCPP_INLINE_VISIBILITY
+    unsigned mark_count() const {return __marked_count_;}
+    _LIBCPP_INLINE_VISIBILITY
+    flag_type flags() const {return __flags_;}
+
+    // locale:
+    _LIBCPP_INLINE_VISIBILITY
+    locale_type imbue(locale_type __loc)
+    {
+        __member_init(ECMAScript);
+        __start_.reset();
+        return __traits_.imbue(__loc);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    locale_type getloc() const {return __traits_.getloc();}
+
+    // swap:
+    void swap(basic_regex& __r);
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    unsigned __loop_count() const {return __loop_count_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool __use_multiline() const
+    {
+        return __get_grammar(__flags_) == ECMAScript && (__flags_ & multiline);
+    }
+
+    template <class _ForwardIterator>
+        void
+        __init(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_basic_reg_exp(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_RE_expression(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_simple_RE(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_nondupl_RE(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_one_char_or_coll_elem_RE(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_Back_open_paren(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_Back_close_paren(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_Back_open_brace(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_Back_close_brace(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_BACKREF(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_ORD_CHAR(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_QUOTED_CHAR(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_RE_dupl_symbol(_ForwardIterator __first, _ForwardIterator __last,
+                               __owns_one_state<_CharT>* __s,
+                               unsigned __mexp_begin, unsigned __mexp_end);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_ERE_dupl_symbol(_ForwardIterator __first, _ForwardIterator __last,
+                                __owns_one_state<_CharT>* __s,
+                                unsigned __mexp_begin, unsigned __mexp_end);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_bracket_expression(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_follow_list(_ForwardIterator __first, _ForwardIterator __last,
+                            __bracket_expression<_CharT, _Traits>* __ml);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_expression_term(_ForwardIterator __first, _ForwardIterator __last,
+                                __bracket_expression<_CharT, _Traits>* __ml);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_equivalence_class(_ForwardIterator __first, _ForwardIterator __last,
+                                  __bracket_expression<_CharT, _Traits>* __ml);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_character_class(_ForwardIterator __first, _ForwardIterator __last,
+                                __bracket_expression<_CharT, _Traits>* __ml);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_collating_symbol(_ForwardIterator __first, _ForwardIterator __last,
+                                 basic_string<_CharT>& __col_sym);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_DUP_COUNT(_ForwardIterator __first, _ForwardIterator __last, int& __c);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_extended_reg_exp(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_ERE_branch(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_ERE_expression(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_one_char_or_coll_elem_ERE(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_ORD_CHAR_ERE(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_QUOTED_CHAR_ERE(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_ecma_exp(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_alternative(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_term(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_assertion(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_atom(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_atom_escape(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_decimal_escape(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_character_class_escape(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_character_escape(_ForwardIterator __first, _ForwardIterator __last,
+                                 basic_string<_CharT>* __str = nullptr);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_pattern_character(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_grep(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_egrep(_ForwardIterator __first, _ForwardIterator __last);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_class_escape(_ForwardIterator __first, _ForwardIterator __last,
+                          basic_string<_CharT>& __str,
+                          __bracket_expression<_CharT, _Traits>* __ml);
+    template <class _ForwardIterator>
+        _ForwardIterator
+        __parse_awk_escape(_ForwardIterator __first, _ForwardIterator __last,
+                          basic_string<_CharT>* __str = nullptr);
+
+    bool __test_back_ref(_CharT c);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __push_l_anchor();
+    void __push_r_anchor();
+    void __push_match_any();
+    void __push_match_any_but_newline();
+    _LIBCPP_INLINE_VISIBILITY
+    void __push_greedy_inf_repeat(size_t __min, __owns_one_state<_CharT>* __s,
+                                  unsigned __mexp_begin = 0, unsigned __mexp_end = 0)
+        {__push_loop(__min, numeric_limits<size_t>::max(), __s,
+                     __mexp_begin, __mexp_end);}
+    _LIBCPP_INLINE_VISIBILITY
+    void __push_nongreedy_inf_repeat(size_t __min, __owns_one_state<_CharT>* __s,
+                                  unsigned __mexp_begin = 0, unsigned __mexp_end = 0)
+        {__push_loop(__min, numeric_limits<size_t>::max(), __s,
+                     __mexp_begin, __mexp_end, false);}
+    void __push_loop(size_t __min, size_t __max, __owns_one_state<_CharT>* __s,
+                     size_t __mexp_begin = 0, size_t __mexp_end = 0,
+                     bool __greedy = true);
+    __bracket_expression<_CharT, _Traits>* __start_matching_list(bool __negate);
+    void __push_char(value_type __c);
+    void __push_back_ref(int __i);
+    void __push_alternation(__owns_one_state<_CharT>* __sa,
+                            __owns_one_state<_CharT>* __sb);
+    void __push_begin_marked_subexpression();
+    void __push_end_marked_subexpression(unsigned);
+    void __push_empty();
+    void __push_word_boundary(bool);
+    void __push_lookahead(const basic_regex&, bool, unsigned);
+
+    template <class _Allocator>
+        bool
+        __search(const _CharT* __first, const _CharT* __last,
+                 match_results<const _CharT*, _Allocator>& __m,
+                 regex_constants::match_flag_type __flags) const;
+
+    template <class _Allocator>
+        bool
+        __match_at_start(const _CharT* __first, const _CharT* __last,
+                 match_results<const _CharT*, _Allocator>& __m,
+                 regex_constants::match_flag_type __flags, bool) const;
+    template <class _Allocator>
+        bool
+        __match_at_start_ecma(const _CharT* __first, const _CharT* __last,
+                 match_results<const _CharT*, _Allocator>& __m,
+                 regex_constants::match_flag_type __flags, bool) const;
+    template <class _Allocator>
+        bool
+        __match_at_start_posix_nosubs(const _CharT* __first, const _CharT* __last,
+                 match_results<const _CharT*, _Allocator>& __m,
+                 regex_constants::match_flag_type __flags, bool) const;
+    template <class _Allocator>
+        bool
+        __match_at_start_posix_subs(const _CharT* __first, const _CharT* __last,
+                 match_results<const _CharT*, _Allocator>& __m,
+                 regex_constants::match_flag_type __flags, bool) const;
+
+    template <class _Bp, class _Ap, class _Cp, class _Tp>
+    friend
+    bool
+    regex_search(_Bp, _Bp, match_results<_Bp, _Ap>&, const basic_regex<_Cp, _Tp>&,
+                 regex_constants::match_flag_type);
+
+    template <class _Ap, class _Cp, class _Tp>
+    friend
+    bool
+    regex_search(const _Cp*, const _Cp*, match_results<const _Cp*, _Ap>&,
+                 const basic_regex<_Cp, _Tp>&, regex_constants::match_flag_type);
+
+    template <class _Bp, class _Cp, class _Tp>
+    friend
+    bool
+    regex_search(_Bp, _Bp, const basic_regex<_Cp, _Tp>&,
+                 regex_constants::match_flag_type);
+
+    template <class _Cp, class _Tp>
+    friend
+    bool
+    regex_search(const _Cp*, const _Cp*,
+                 const basic_regex<_Cp, _Tp>&, regex_constants::match_flag_type);
+
+    template <class _Cp, class _Ap, class _Tp>
+    friend
+    bool
+    regex_search(const _Cp*, match_results<const _Cp*, _Ap>&, const basic_regex<_Cp, _Tp>&,
+                 regex_constants::match_flag_type);
+
+    template <class _ST, class _SA, class _Cp, class _Tp>
+    friend
+    bool
+    regex_search(const basic_string<_Cp, _ST, _SA>& __s,
+                 const basic_regex<_Cp, _Tp>& __e,
+                 regex_constants::match_flag_type __flags);
+
+    template <class _ST, class _SA, class _Ap, class _Cp, class _Tp>
+    friend
+    bool
+    regex_search(const basic_string<_Cp, _ST, _SA>& __s,
+                 match_results<typename basic_string<_Cp, _ST, _SA>::const_iterator, _Ap>&,
+                 const basic_regex<_Cp, _Tp>& __e,
+                 regex_constants::match_flag_type __flags);
+
+    template <class _Iter, class _Ap, class _Cp, class _Tp>
+    friend
+    bool
+    regex_search(__wrap_iter<_Iter> __first,
+                 __wrap_iter<_Iter> __last,
+                 match_results<__wrap_iter<_Iter>, _Ap>& __m,
+                 const basic_regex<_Cp, _Tp>& __e,
+                 regex_constants::match_flag_type __flags);
+
+    template <class, class> friend class __lookahead;
+};
+
+#if _LIBCPP_STD_VER >= 17
+template <class _ForwardIterator,
+          class = typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value, nullptr_t>::type
+>
+basic_regex(_ForwardIterator, _ForwardIterator,
+            regex_constants::syntax_option_type = regex_constants::ECMAScript)
+    -> basic_regex<typename iterator_traits<_ForwardIterator>::value_type>;
+#endif
+
+template <class _CharT, class _Traits>
+    const regex_constants::syntax_option_type basic_regex<_CharT, _Traits>::icase;
+template <class _CharT, class _Traits>
+    const regex_constants::syntax_option_type basic_regex<_CharT, _Traits>::nosubs;
+template <class _CharT, class _Traits>
+    const regex_constants::syntax_option_type basic_regex<_CharT, _Traits>::optimize;
+template <class _CharT, class _Traits>
+    const regex_constants::syntax_option_type basic_regex<_CharT, _Traits>::collate;
+template <class _CharT, class _Traits>
+    const regex_constants::syntax_option_type basic_regex<_CharT, _Traits>::ECMAScript;
+template <class _CharT, class _Traits>
+    const regex_constants::syntax_option_type basic_regex<_CharT, _Traits>::basic;
+template <class _CharT, class _Traits>
+    const regex_constants::syntax_option_type basic_regex<_CharT, _Traits>::extended;
+template <class _CharT, class _Traits>
+    const regex_constants::syntax_option_type basic_regex<_CharT, _Traits>::awk;
+template <class _CharT, class _Traits>
+    const regex_constants::syntax_option_type basic_regex<_CharT, _Traits>::grep;
+template <class _CharT, class _Traits>
+    const regex_constants::syntax_option_type basic_regex<_CharT, _Traits>::egrep;
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::swap(basic_regex& __r)
+{
+    using _VSTD::swap;
+    swap(__traits_, __r.__traits_);
+    swap(__flags_, __r.__flags_);
+    swap(__marked_count_, __r.__marked_count_);
+    swap(__loop_count_, __r.__loop_count_);
+    swap(__open_count_, __r.__open_count_);
+    swap(__start_, __r.__start_);
+    swap(__end_, __r.__end_);
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(basic_regex<_CharT, _Traits>& __x, basic_regex<_CharT, _Traits>& __y)
+{
+    return __x.swap(__y);
+}
+
+// __lookahead
+
+template <class _CharT, class _Traits>
+class __lookahead
+    : public __owns_one_state<_CharT>
+{
+    typedef __owns_one_state<_CharT> base;
+
+    basic_regex<_CharT, _Traits> __exp_;
+    unsigned __mexp_;
+    bool __invert_;
+
+    __lookahead(const __lookahead&);
+    __lookahead& operator=(const __lookahead&);
+public:
+    typedef _VSTD::__state<_CharT> __state;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __lookahead(const basic_regex<_CharT, _Traits>& __exp, bool __invert, __node<_CharT>* __s, unsigned __mexp)
+        : base(__s), __exp_(__exp), __mexp_(__mexp), __invert_(__invert) {}
+
+    virtual void __exec(__state&) const;
+};
+
+template <class _CharT, class _Traits>
+void
+__lookahead<_CharT, _Traits>::__exec(__state& __s) const
+{
+    match_results<const _CharT*> __m;
+    __m.__init(1 + __exp_.mark_count(), __s.__current_, __s.__last_);
+    bool __matched = __exp_.__match_at_start_ecma(
+        __s.__current_, __s.__last_,
+        __m,
+        (__s.__flags_ | regex_constants::match_continuous) &
+        ~regex_constants::__full_match,
+        __s.__at_first_ && __s.__current_ == __s.__first_);
+    if (__matched != __invert_)
+    {
+        __s.__do_ = __state::__accept_but_not_consume;
+        __s.__node_ = this->first();
+        for (unsigned __i = 1; __i < __m.size(); ++__i) {
+            __s.__sub_matches_[__mexp_ + __i - 1] = __m.__matches_[__i];
+        }
+    }
+    else
+    {
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+void
+basic_regex<_CharT, _Traits>::__init(_ForwardIterator __first, _ForwardIterator __last)
+{
+    if (__get_grammar(__flags_) == 0) __flags_ |= regex_constants::ECMAScript;
+    _ForwardIterator __temp = __parse(__first, __last);
+    if ( __temp != __last)
+        __throw_regex_error<regex_constants::__re_err_parse>();
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse(_ForwardIterator __first,
+                                      _ForwardIterator __last)
+{
+    {
+        unique_ptr<__node> __h(new __end_state<_CharT>);
+        __start_.reset(new __empty_state<_CharT>(__h.get()));
+        __h.release();
+        __end_ = __start_.get();
+    }
+    switch (__get_grammar(__flags_))
+    {
+    case ECMAScript:
+        __first = __parse_ecma_exp(__first, __last);
+        break;
+    case basic:
+        __first = __parse_basic_reg_exp(__first, __last);
+        break;
+    case extended:
+    case awk:
+        __first = __parse_extended_reg_exp(__first, __last);
+        break;
+    case grep:
+        __first = __parse_grep(__first, __last);
+        break;
+    case egrep:
+        __first = __parse_egrep(__first, __last);
+        break;
+    default:
+        __throw_regex_error<regex_constants::__re_err_grammar>();
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_basic_reg_exp(_ForwardIterator __first,
+                                                    _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        if (*__first == '^')
+        {
+            __push_l_anchor();
+            ++__first;
+        }
+        if (__first != __last)
+        {
+            __first = __parse_RE_expression(__first, __last);
+            if (__first != __last)
+            {
+                _ForwardIterator __temp = _VSTD::next(__first);
+                if (__temp == __last && *__first == '$')
+                {
+                    __push_r_anchor();
+                    ++__first;
+                }
+            }
+        }
+        if (__first != __last)
+            __throw_regex_error<regex_constants::__re_err_empty>();
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_extended_reg_exp(_ForwardIterator __first,
+                                                       _ForwardIterator __last)
+{
+    __owns_one_state<_CharT>* __sa = __end_;
+    _ForwardIterator __temp = __parse_ERE_branch(__first, __last);
+    if (__temp == __first)
+        __throw_regex_error<regex_constants::__re_err_empty>();
+    __first = __temp;
+    while (__first != __last && *__first == '|')
+    {
+        __owns_one_state<_CharT>* __sb = __end_;
+        __temp = __parse_ERE_branch(++__first, __last);
+        if (__temp == __first)
+            __throw_regex_error<regex_constants::__re_err_empty>();
+        __push_alternation(__sa, __sb);
+        __first = __temp;
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_ERE_branch(_ForwardIterator __first,
+                                                 _ForwardIterator __last)
+{
+    _ForwardIterator __temp = __parse_ERE_expression(__first, __last);
+    if (__temp == __first)
+        __throw_regex_error<regex_constants::__re_err_empty>();
+    do
+    {
+        __first = __temp;
+        __temp = __parse_ERE_expression(__first, __last);
+    } while (__temp != __first);
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_ERE_expression(_ForwardIterator __first,
+                                                     _ForwardIterator __last)
+{
+    __owns_one_state<_CharT>* __e = __end_;
+    unsigned __mexp_begin = __marked_count_;
+    _ForwardIterator __temp = __parse_one_char_or_coll_elem_ERE(__first, __last);
+    if (__temp == __first && __temp != __last)
+    {
+        switch (*__temp)
+        {
+        case '^':
+            __push_l_anchor();
+            ++__temp;
+            break;
+        case '$':
+            __push_r_anchor();
+            ++__temp;
+            break;
+        case '(':
+            __push_begin_marked_subexpression();
+            unsigned __temp_count = __marked_count_;
+            ++__open_count_;
+            __temp = __parse_extended_reg_exp(++__temp, __last);
+            if (__temp == __last || *__temp != ')')
+                __throw_regex_error<regex_constants::error_paren>();
+            __push_end_marked_subexpression(__temp_count);
+            --__open_count_;
+            ++__temp;
+            break;
+        }
+    }
+    if (__temp != __first)
+        __temp = __parse_ERE_dupl_symbol(__temp, __last, __e, __mexp_begin+1,
+                                         __marked_count_+1);
+    __first = __temp;
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_RE_expression(_ForwardIterator __first,
+                                                    _ForwardIterator __last)
+{
+    while (true)
+    {
+        _ForwardIterator __temp = __parse_simple_RE(__first, __last);
+        if (__temp == __first)
+            break;
+        __first = __temp;
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_simple_RE(_ForwardIterator __first,
+                                                _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        __owns_one_state<_CharT>* __e = __end_;
+        unsigned __mexp_begin = __marked_count_;
+        _ForwardIterator __temp = __parse_nondupl_RE(__first, __last);
+        if (__temp != __first)
+            __first = __parse_RE_dupl_symbol(__temp, __last, __e,
+                                             __mexp_begin+1, __marked_count_+1);
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_nondupl_RE(_ForwardIterator __first,
+                                                 _ForwardIterator __last)
+{
+    _ForwardIterator __temp = __first;
+    __first = __parse_one_char_or_coll_elem_RE(__first, __last);
+    if (__temp == __first)
+    {
+        __temp = __parse_Back_open_paren(__first, __last);
+        if (__temp != __first)
+        {
+            __push_begin_marked_subexpression();
+            unsigned __temp_count = __marked_count_;
+            __first = __parse_RE_expression(__temp, __last);
+            __temp = __parse_Back_close_paren(__first, __last);
+            if (__temp == __first)
+                __throw_regex_error<regex_constants::error_paren>();
+            __push_end_marked_subexpression(__temp_count);
+            __first = __temp;
+        }
+        else
+            __first = __parse_BACKREF(__first, __last);
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_one_char_or_coll_elem_RE(
+                                                       _ForwardIterator __first,
+                                                       _ForwardIterator __last)
+{
+    _ForwardIterator __temp = __parse_ORD_CHAR(__first, __last);
+    if (__temp == __first)
+    {
+        __temp = __parse_QUOTED_CHAR(__first, __last);
+        if (__temp == __first)
+        {
+            if (__temp != __last && *__temp == '.')
+            {
+                __push_match_any();
+                ++__temp;
+            }
+            else
+                __temp = __parse_bracket_expression(__first, __last);
+        }
+    }
+    __first = __temp;
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_one_char_or_coll_elem_ERE(
+                                                       _ForwardIterator __first,
+                                                       _ForwardIterator __last)
+{
+    _ForwardIterator __temp = __parse_ORD_CHAR_ERE(__first, __last);
+    if (__temp == __first)
+    {
+        __temp = __parse_QUOTED_CHAR_ERE(__first, __last);
+        if (__temp == __first)
+        {
+            if (__temp != __last && *__temp == '.')
+            {
+                __push_match_any();
+                ++__temp;
+            }
+            else
+                __temp = __parse_bracket_expression(__first, __last);
+        }
+    }
+    __first = __temp;
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_Back_open_paren(_ForwardIterator __first,
+                                                      _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __temp = _VSTD::next(__first);
+        if (__temp != __last)
+        {
+            if (*__first == '\\' && *__temp == '(')
+                __first = ++__temp;
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_Back_close_paren(_ForwardIterator __first,
+                                                       _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __temp = _VSTD::next(__first);
+        if (__temp != __last)
+        {
+            if (*__first == '\\' && *__temp == ')')
+                __first = ++__temp;
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_Back_open_brace(_ForwardIterator __first,
+                                                      _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __temp = _VSTD::next(__first);
+        if (__temp != __last)
+        {
+            if (*__first == '\\' && *__temp == '{')
+                __first = ++__temp;
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_Back_close_brace(_ForwardIterator __first,
+                                                       _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __temp = _VSTD::next(__first);
+        if (__temp != __last)
+        {
+            if (*__first == '\\' && *__temp == '}')
+                __first = ++__temp;
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_BACKREF(_ForwardIterator __first,
+                                              _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __temp = _VSTD::next(__first);
+        if (__temp != __last && *__first == '\\' && __test_back_ref(*__temp))
+            __first = ++__temp;
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_ORD_CHAR(_ForwardIterator __first,
+                                               _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __temp = _VSTD::next(__first);
+        if (__temp == __last && *__first == '$')
+            return __first;
+        // Not called inside a bracket
+        if (*__first == '.' || *__first == '\\' || *__first == '[')
+            return __first;
+        __push_char(*__first);
+        ++__first;
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_ORD_CHAR_ERE(_ForwardIterator __first,
+                                                   _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        switch (*__first)
+        {
+        case '^':
+        case '.':
+        case '[':
+        case '$':
+        case '(':
+        case '|':
+        case '*':
+        case '+':
+        case '?':
+        case '{':
+        case '\\':
+            break;
+        case ')':
+            if (__open_count_ == 0)
+            {
+                __push_char(*__first);
+                ++__first;
+            }
+            break;
+        default:
+            __push_char(*__first);
+            ++__first;
+            break;
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_QUOTED_CHAR(_ForwardIterator __first,
+                                                  _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __temp = _VSTD::next(__first);
+        if (__temp != __last)
+        {
+            if (*__first == '\\')
+            {
+                switch (*__temp)
+                {
+                case '^':
+                case '.':
+                case '*':
+                case '[':
+                case '$':
+                case '\\':
+                    __push_char(*__temp);
+                    __first = ++__temp;
+                    break;
+                }
+            }
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_QUOTED_CHAR_ERE(_ForwardIterator __first,
+                                                      _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __temp = _VSTD::next(__first);
+        if (__temp != __last)
+        {
+            if (*__first == '\\')
+            {
+                switch (*__temp)
+                {
+                case '^':
+                case '.':
+                case '*':
+                case '[':
+                case '$':
+                case '\\':
+                case '(':
+                case ')':
+                case '|':
+                case '+':
+                case '?':
+                case '{':
+                case '}':
+                    __push_char(*__temp);
+                    __first = ++__temp;
+                    break;
+                default:
+                    if (__get_grammar(__flags_) == awk)
+                        __first = __parse_awk_escape(++__first, __last);
+                    else if(__test_back_ref(*__temp))
+                        __first = ++__temp;
+                    break;
+                }
+            }
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_RE_dupl_symbol(_ForwardIterator __first,
+                                                     _ForwardIterator __last,
+                                                     __owns_one_state<_CharT>* __s,
+                                                     unsigned __mexp_begin,
+                                                     unsigned __mexp_end)
+{
+    if (__first != __last)
+    {
+        if (*__first == '*')
+        {
+            __push_greedy_inf_repeat(0, __s, __mexp_begin, __mexp_end);
+            ++__first;
+        }
+        else
+        {
+            _ForwardIterator __temp = __parse_Back_open_brace(__first, __last);
+            if (__temp != __first)
+            {
+                int __min = 0;
+                __first = __temp;
+                __temp = __parse_DUP_COUNT(__first, __last, __min);
+                if (__temp == __first)
+                    __throw_regex_error<regex_constants::error_badbrace>();
+                __first = __temp;
+                if (__first == __last)
+                    __throw_regex_error<regex_constants::error_brace>();
+                if (*__first != ',')
+                {
+                    __temp = __parse_Back_close_brace(__first, __last);
+                    if (__temp == __first)
+                        __throw_regex_error<regex_constants::error_brace>();
+                    __push_loop(__min, __min, __s, __mexp_begin, __mexp_end,
+                                    true);
+                    __first = __temp;
+                }
+                else
+                {
+                    ++__first;  // consume ','
+                    int __max = -1;
+                    __first = __parse_DUP_COUNT(__first, __last, __max);
+                    __temp = __parse_Back_close_brace(__first, __last);
+                    if (__temp == __first)
+                        __throw_regex_error<regex_constants::error_brace>();
+                    if (__max == -1)
+                        __push_greedy_inf_repeat(__min, __s, __mexp_begin, __mexp_end);
+                    else
+                    {
+                        if (__max < __min)
+                            __throw_regex_error<regex_constants::error_badbrace>();
+                        __push_loop(__min, __max, __s, __mexp_begin, __mexp_end,
+                                    true);
+                    }
+                    __first = __temp;
+                }
+            }
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_ERE_dupl_symbol(_ForwardIterator __first,
+                                                      _ForwardIterator __last,
+                                                      __owns_one_state<_CharT>* __s,
+                                                      unsigned __mexp_begin,
+                                                      unsigned __mexp_end)
+{
+    if (__first != __last)
+    {
+        unsigned __grammar = __get_grammar(__flags_);
+        switch (*__first)
+        {
+        case '*':
+            ++__first;
+            if (__grammar == ECMAScript && __first != __last && *__first == '?')
+            {
+                ++__first;
+                __push_nongreedy_inf_repeat(0, __s, __mexp_begin, __mexp_end);
+            }
+            else
+                __push_greedy_inf_repeat(0, __s, __mexp_begin, __mexp_end);
+            break;
+        case '+':
+            ++__first;
+            if (__grammar == ECMAScript && __first != __last && *__first == '?')
+            {
+                ++__first;
+                __push_nongreedy_inf_repeat(1, __s, __mexp_begin, __mexp_end);
+            }
+            else
+                __push_greedy_inf_repeat(1, __s, __mexp_begin, __mexp_end);
+            break;
+        case '?':
+            ++__first;
+            if (__grammar == ECMAScript && __first != __last && *__first == '?')
+            {
+                ++__first;
+                __push_loop(0, 1, __s, __mexp_begin, __mexp_end, false);
+            }
+            else
+                __push_loop(0, 1, __s, __mexp_begin, __mexp_end);
+            break;
+        case '{':
+            {
+                int __min;
+                _ForwardIterator __temp = __parse_DUP_COUNT(++__first, __last, __min);
+                if (__temp == __first)
+                    __throw_regex_error<regex_constants::error_badbrace>();
+                __first = __temp;
+                if (__first == __last)
+                    __throw_regex_error<regex_constants::error_brace>();
+                switch (*__first)
+                {
+                case '}':
+                    ++__first;
+                    if (__grammar == ECMAScript && __first != __last && *__first == '?')
+                    {
+                        ++__first;
+                        __push_loop(__min, __min, __s, __mexp_begin, __mexp_end, false);
+                    }
+                    else
+                        __push_loop(__min, __min, __s, __mexp_begin, __mexp_end);
+                    break;
+                case ',':
+                    ++__first;
+                    if (__first == __last)
+                        __throw_regex_error<regex_constants::error_badbrace>();
+                    if (*__first == '}')
+                    {
+                        ++__first;
+                        if (__grammar == ECMAScript && __first != __last && *__first == '?')
+                        {
+                            ++__first;
+                            __push_nongreedy_inf_repeat(__min, __s, __mexp_begin, __mexp_end);
+                        }
+                        else
+                            __push_greedy_inf_repeat(__min, __s, __mexp_begin, __mexp_end);
+                    }
+                    else
+                    {
+                        int __max = -1;
+                        __temp = __parse_DUP_COUNT(__first, __last, __max);
+                        if (__temp == __first)
+                            __throw_regex_error<regex_constants::error_brace>();
+                        __first = __temp;
+                        if (__first == __last || *__first != '}')
+                            __throw_regex_error<regex_constants::error_brace>();
+                        ++__first;
+                        if (__max < __min)
+                            __throw_regex_error<regex_constants::error_badbrace>();
+                        if (__grammar == ECMAScript && __first != __last && *__first == '?')
+                        {
+                            ++__first;
+                            __push_loop(__min, __max, __s, __mexp_begin, __mexp_end, false);
+                        }
+                        else
+                            __push_loop(__min, __max, __s, __mexp_begin, __mexp_end);
+                    }
+                    break;
+                default:
+                    __throw_regex_error<regex_constants::error_badbrace>();
+                }
+            }
+            break;
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_bracket_expression(_ForwardIterator __first,
+                                                         _ForwardIterator __last)
+{
+    if (__first != __last && *__first == '[')
+    {
+        ++__first;
+        if (__first == __last)
+            __throw_regex_error<regex_constants::error_brack>();
+        bool __negate = false;
+        if (*__first == '^')
+        {
+            ++__first;
+            __negate = true;
+        }
+        __bracket_expression<_CharT, _Traits>* __ml = __start_matching_list(__negate);
+        // __ml owned by *this
+        if (__first == __last)
+            __throw_regex_error<regex_constants::error_brack>();
+        if (__get_grammar(__flags_) != ECMAScript && *__first == ']')
+        {
+            __ml->__add_char(']');
+            ++__first;
+        }
+        __first = __parse_follow_list(__first, __last, __ml);
+        if (__first == __last)
+            __throw_regex_error<regex_constants::error_brack>();
+        if (*__first == '-')
+        {
+            __ml->__add_char('-');
+            ++__first;
+        }
+        if (__first == __last || *__first != ']')
+            __throw_regex_error<regex_constants::error_brack>();
+        ++__first;
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_follow_list(_ForwardIterator __first,
+                                    _ForwardIterator __last,
+                                    __bracket_expression<_CharT, _Traits>* __ml)
+{
+    if (__first != __last)
+    {
+        while (true)
+        {
+            _ForwardIterator __temp = __parse_expression_term(__first, __last,
+                                                              __ml);
+            if (__temp == __first)
+                break;
+            __first = __temp;
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_expression_term(_ForwardIterator __first,
+                                    _ForwardIterator __last,
+                                    __bracket_expression<_CharT, _Traits>* __ml)
+{
+    if (__first != __last && *__first != ']')
+    {
+        _ForwardIterator __temp = _VSTD::next(__first);
+        basic_string<_CharT> __start_range;
+        if (__temp != __last && *__first == '[')
+        {
+            if (*__temp == '=')
+                return __parse_equivalence_class(++__temp, __last, __ml);
+            else if (*__temp == ':')
+                return __parse_character_class(++__temp, __last, __ml);
+            else if (*__temp == '.')
+                __first = __parse_collating_symbol(++__temp, __last, __start_range);
+        }
+        unsigned __grammar = __get_grammar(__flags_);
+        if (__start_range.empty())
+        {
+            if ((__grammar == ECMAScript || __grammar == awk) && *__first == '\\')
+            {
+                if (__grammar == ECMAScript)
+                    __first = __parse_class_escape(++__first, __last, __start_range, __ml);
+                else
+                    __first = __parse_awk_escape(++__first, __last, &__start_range);
+            }
+            else
+            {
+                __start_range = *__first;
+                ++__first;
+            }
+        }
+        if (__first != __last && *__first != ']')
+        {
+            __temp = _VSTD::next(__first);
+            if (__temp != __last && *__first == '-' && *__temp != ']')
+            {
+                // parse a range
+                basic_string<_CharT> __end_range;
+                __first = __temp;
+                ++__temp;
+                if (__temp != __last && *__first == '[' && *__temp == '.')
+                    __first = __parse_collating_symbol(++__temp, __last, __end_range);
+                else
+                {
+                    if ((__grammar == ECMAScript || __grammar == awk) && *__first == '\\')
+                    {
+                        if (__grammar == ECMAScript)
+                            __first = __parse_class_escape(++__first, __last,
+                                                           __end_range, __ml);
+                        else
+                            __first = __parse_awk_escape(++__first, __last,
+                                                         &__end_range);
+                    }
+                    else
+                    {
+                        __end_range = *__first;
+                        ++__first;
+                    }
+                }
+                __ml->__add_range(_VSTD::move(__start_range), _VSTD::move(__end_range));
+            }
+            else if (!__start_range.empty())
+            {
+                if (__start_range.size() == 1)
+                    __ml->__add_char(__start_range[0]);
+                else
+                    __ml->__add_digraph(__start_range[0], __start_range[1]);
+            }
+        }
+        else if (!__start_range.empty())
+        {
+            if (__start_range.size() == 1)
+                __ml->__add_char(__start_range[0]);
+            else
+                __ml->__add_digraph(__start_range[0], __start_range[1]);
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_class_escape(_ForwardIterator __first,
+                          _ForwardIterator __last,
+                          basic_string<_CharT>& __str,
+                          __bracket_expression<_CharT, _Traits>* __ml)
+{
+    if (__first == __last)
+        __throw_regex_error<regex_constants::error_escape>();
+    switch (*__first)
+    {
+    case 0:
+        __str = *__first;
+        return ++__first;
+    case 'b':
+        __str = _CharT(8);
+        return ++__first;
+    case 'd':
+        __ml->__add_class(ctype_base::digit);
+        return ++__first;
+    case 'D':
+        __ml->__add_neg_class(ctype_base::digit);
+        return ++__first;
+    case 's':
+        __ml->__add_class(ctype_base::space);
+        return ++__first;
+    case 'S':
+        __ml->__add_neg_class(ctype_base::space);
+        return ++__first;
+    case 'w':
+        __ml->__add_class(ctype_base::alnum);
+        __ml->__add_char('_');
+        return ++__first;
+    case 'W':
+        __ml->__add_neg_class(ctype_base::alnum);
+        __ml->__add_neg_char('_');
+        return ++__first;
+    }
+    __first = __parse_character_escape(__first, __last, &__str);
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_awk_escape(_ForwardIterator __first,
+                          _ForwardIterator __last,
+                          basic_string<_CharT>* __str)
+{
+    if (__first == __last)
+        __throw_regex_error<regex_constants::error_escape>();
+    switch (*__first)
+    {
+    case '\\':
+    case '"':
+    case '/':
+        if (__str)
+            *__str = *__first;
+        else
+            __push_char(*__first);
+        return ++__first;
+    case 'a':
+        if (__str)
+            *__str = _CharT(7);
+        else
+            __push_char(_CharT(7));
+        return ++__first;
+    case 'b':
+        if (__str)
+            *__str = _CharT(8);
+        else
+            __push_char(_CharT(8));
+        return ++__first;
+    case 'f':
+        if (__str)
+            *__str = _CharT(0xC);
+        else
+            __push_char(_CharT(0xC));
+        return ++__first;
+    case 'n':
+        if (__str)
+            *__str = _CharT(0xA);
+        else
+            __push_char(_CharT(0xA));
+        return ++__first;
+    case 'r':
+        if (__str)
+            *__str = _CharT(0xD);
+        else
+            __push_char(_CharT(0xD));
+        return ++__first;
+    case 't':
+        if (__str)
+            *__str = _CharT(0x9);
+        else
+            __push_char(_CharT(0x9));
+        return ++__first;
+    case 'v':
+        if (__str)
+            *__str = _CharT(0xB);
+        else
+            __push_char(_CharT(0xB));
+        return ++__first;
+    }
+    if ('0' <= *__first && *__first <= '7')
+    {
+        unsigned __val = *__first - '0';
+        if (++__first != __last && ('0' <= *__first && *__first <= '7'))
+        {
+            __val = 8 * __val + *__first - '0';
+            if (++__first != __last && ('0' <= *__first && *__first <= '7'))
+                __val = 8 * __val + *__first++ - '0';
+        }
+        if (__str)
+            *__str = _CharT(__val);
+        else
+            __push_char(_CharT(__val));
+    }
+    else
+        __throw_regex_error<regex_constants::error_escape>();
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_equivalence_class(_ForwardIterator __first,
+                                    _ForwardIterator __last,
+                                    __bracket_expression<_CharT, _Traits>* __ml)
+{
+    // Found [=
+    //   This means =] must exist
+    value_type _Equal_close[2] = {'=', ']'};
+    _ForwardIterator __temp = _VSTD::search(__first, __last, _Equal_close,
+                                                            _Equal_close+2);
+    if (__temp == __last)
+        __throw_regex_error<regex_constants::error_brack>();
+    // [__first, __temp) contains all text in [= ... =]
+    string_type __collate_name =
+        __traits_.lookup_collatename(__first, __temp);
+    if (__collate_name.empty())
+        __throw_regex_error<regex_constants::error_collate>();
+    string_type __equiv_name =
+        __traits_.transform_primary(__collate_name.begin(),
+                                    __collate_name.end());
+    if (!__equiv_name.empty())
+        __ml->__add_equivalence(__equiv_name);
+    else
+    {
+        switch (__collate_name.size())
+        {
+        case 1:
+            __ml->__add_char(__collate_name[0]);
+            break;
+        case 2:
+            __ml->__add_digraph(__collate_name[0], __collate_name[1]);
+            break;
+        default:
+            __throw_regex_error<regex_constants::error_collate>();
+        }
+    }
+    __first = _VSTD::next(__temp, 2);
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_character_class(_ForwardIterator __first,
+                                    _ForwardIterator __last,
+                                    __bracket_expression<_CharT, _Traits>* __ml)
+{
+    // Found [:
+    //   This means :] must exist
+    value_type _Colon_close[2] = {':', ']'};
+    _ForwardIterator __temp = _VSTD::search(__first, __last, _Colon_close,
+                                                            _Colon_close+2);
+    if (__temp == __last)
+        __throw_regex_error<regex_constants::error_brack>();
+    // [__first, __temp) contains all text in [: ... :]
+    typedef typename _Traits::char_class_type char_class_type;
+    char_class_type __class_type =
+        __traits_.lookup_classname(__first, __temp, __flags_ & icase);
+    if (__class_type == 0)
+        __throw_regex_error<regex_constants::error_ctype>();
+    __ml->__add_class(__class_type);
+    __first = _VSTD::next(__temp, 2);
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_collating_symbol(_ForwardIterator __first,
+                                                _ForwardIterator __last,
+                                                basic_string<_CharT>& __col_sym)
+{
+    // Found [.
+    //   This means .] must exist
+    value_type _Dot_close[2] = {'.', ']'};
+    _ForwardIterator __temp = _VSTD::search(__first, __last, _Dot_close,
+                                                            _Dot_close+2);
+    if (__temp == __last)
+        __throw_regex_error<regex_constants::error_brack>();
+    // [__first, __temp) contains all text in [. ... .]
+    __col_sym = __traits_.lookup_collatename(__first, __temp);
+    switch (__col_sym.size())
+    {
+    case 1:
+    case 2:
+        break;
+    default:
+        __throw_regex_error<regex_constants::error_collate>();
+    }
+    __first = _VSTD::next(__temp, 2);
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_DUP_COUNT(_ForwardIterator __first,
+                                                _ForwardIterator __last,
+                                                int& __c)
+{
+    if (__first != __last )
+    {
+        int __val = __traits_.value(*__first, 10);
+        if ( __val != -1 )
+        {
+            __c = __val;
+            for (++__first;
+                 __first != __last && ( __val = __traits_.value(*__first, 10)) != -1;
+                 ++__first)
+            {
+                if (__c >= numeric_limits<int>::max() / 10)
+                    __throw_regex_error<regex_constants::error_badbrace>();
+                __c *= 10;
+                __c += __val;
+            }
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_ecma_exp(_ForwardIterator __first,
+                                               _ForwardIterator __last)
+{
+    __owns_one_state<_CharT>* __sa = __end_;
+    _ForwardIterator __temp = __parse_alternative(__first, __last);
+    if (__temp == __first)
+        __push_empty();
+    __first = __temp;
+    while (__first != __last && *__first == '|')
+    {
+        __owns_one_state<_CharT>* __sb = __end_;
+        __temp = __parse_alternative(++__first, __last);
+        if (__temp == __first)
+            __push_empty();
+        __push_alternation(__sa, __sb);
+        __first = __temp;
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_alternative(_ForwardIterator __first,
+                                                  _ForwardIterator __last)
+{
+    while (true)
+    {
+        _ForwardIterator __temp = __parse_term(__first, __last);
+        if (__temp == __first)
+            break;
+        __first = __temp;
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_term(_ForwardIterator __first,
+                                           _ForwardIterator __last)
+{
+    _ForwardIterator __temp = __parse_assertion(__first, __last);
+    if (__temp == __first)
+    {
+        __owns_one_state<_CharT>* __e = __end_;
+        unsigned __mexp_begin = __marked_count_;
+        __temp = __parse_atom(__first, __last);
+        if (__temp != __first)
+            __first = __parse_ERE_dupl_symbol(__temp, __last, __e,
+                                              __mexp_begin+1, __marked_count_+1);
+    }
+    else
+        __first = __temp;
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_assertion(_ForwardIterator __first,
+                                                _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        switch (*__first)
+        {
+        case '^':
+            __push_l_anchor();
+            ++__first;
+            break;
+        case '$':
+            __push_r_anchor();
+            ++__first;
+            break;
+        case '\\':
+            {
+                _ForwardIterator __temp = _VSTD::next(__first);
+                if (__temp != __last)
+                {
+                    if (*__temp == 'b')
+                    {
+                        __push_word_boundary(false);
+                        __first = ++__temp;
+                    }
+                    else if (*__temp == 'B')
+                    {
+                        __push_word_boundary(true);
+                        __first = ++__temp;
+                    }
+                }
+            }
+            break;
+        case '(':
+            {
+                _ForwardIterator __temp = _VSTD::next(__first);
+                if (__temp != __last && *__temp == '?')
+                {
+                    if (++__temp != __last)
+                    {
+                        switch (*__temp)
+                        {
+                        case '=':
+                            {
+                                basic_regex __exp;
+                                __exp.__flags_ = __flags_;
+                                __temp = __exp.__parse(++__temp, __last);
+                                unsigned __mexp = __exp.__marked_count_;
+                                __push_lookahead(_VSTD::move(__exp), false, __marked_count_);
+                                __marked_count_ += __mexp;
+                                if (__temp == __last || *__temp != ')')
+                                    __throw_regex_error<regex_constants::error_paren>();
+                                __first = ++__temp;
+                            }
+                            break;
+                        case '!':
+                            {
+                                basic_regex __exp;
+                                __exp.__flags_ = __flags_;
+                                __temp = __exp.__parse(++__temp, __last);
+                                unsigned __mexp = __exp.__marked_count_;
+                                __push_lookahead(_VSTD::move(__exp), true, __marked_count_);
+                                __marked_count_ += __mexp;
+                                if (__temp == __last || *__temp != ')')
+                                    __throw_regex_error<regex_constants::error_paren>();
+                                __first = ++__temp;
+                            }
+                            break;
+                        }
+                    }
+                }
+            }
+            break;
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_atom(_ForwardIterator __first,
+                                           _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        switch (*__first)
+        {
+        case '.':
+            __push_match_any_but_newline();
+            ++__first;
+            break;
+        case '\\':
+            __first = __parse_atom_escape(__first, __last);
+            break;
+        case '[':
+            __first = __parse_bracket_expression(__first, __last);
+            break;
+        case '(':
+            {
+                ++__first;
+                if (__first == __last)
+                    __throw_regex_error<regex_constants::error_paren>();
+                _ForwardIterator __temp = _VSTD::next(__first);
+                if (__temp != __last && *__first == '?' && *__temp == ':')
+                {
+                    ++__open_count_;
+                    __first = __parse_ecma_exp(++__temp, __last);
+                    if (__first == __last || *__first != ')')
+                        __throw_regex_error<regex_constants::error_paren>();
+                    --__open_count_;
+                    ++__first;
+                }
+                else
+                {
+                    __push_begin_marked_subexpression();
+                    unsigned __temp_count = __marked_count_;
+                    ++__open_count_;
+                    __first = __parse_ecma_exp(__first, __last);
+                    if (__first == __last || *__first != ')')
+                        __throw_regex_error<regex_constants::error_paren>();
+                    __push_end_marked_subexpression(__temp_count);
+                    --__open_count_;
+                    ++__first;
+                }
+            }
+            break;
+        case '*':
+        case '+':
+        case '?':
+        case '{':
+            __throw_regex_error<regex_constants::error_badrepeat>();
+            break;
+        default:
+            __first = __parse_pattern_character(__first, __last);
+            break;
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_atom_escape(_ForwardIterator __first,
+                                                  _ForwardIterator __last)
+{
+    if (__first != __last && *__first == '\\')
+    {
+        _ForwardIterator __t1 = _VSTD::next(__first);
+        if (__t1 == __last)
+            __throw_regex_error<regex_constants::error_escape>();
+
+        _ForwardIterator __t2 = __parse_decimal_escape(__t1, __last);
+        if (__t2 != __t1)
+            __first = __t2;
+        else
+        {
+            __t2 = __parse_character_class_escape(__t1, __last);
+            if (__t2 != __t1)
+                __first = __t2;
+            else
+            {
+                __t2 = __parse_character_escape(__t1, __last);
+                if (__t2 != __t1)
+                    __first = __t2;
+            }
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_decimal_escape(_ForwardIterator __first,
+                                                     _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        if (*__first == '0')
+        {
+            __push_char(_CharT());
+            ++__first;
+        }
+        else if ('1' <= *__first && *__first <= '9')
+        {
+            unsigned __v = *__first - '0';
+            for (++__first;
+                    __first != __last && '0' <= *__first && *__first <= '9'; ++__first)
+                {
+                if (__v >= numeric_limits<unsigned>::max() / 10)
+                    __throw_regex_error<regex_constants::error_backref>();
+                __v = 10 * __v + *__first - '0';
+                }
+            if (__v == 0 || __v > mark_count())
+                __throw_regex_error<regex_constants::error_backref>();
+            __push_back_ref(__v);
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_character_class_escape(_ForwardIterator __first,
+                                                             _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        __bracket_expression<_CharT, _Traits>* __ml;
+        switch (*__first)
+        {
+        case 'd':
+            __ml = __start_matching_list(false);
+            __ml->__add_class(ctype_base::digit);
+            ++__first;
+            break;
+        case 'D':
+            __ml = __start_matching_list(true);
+            __ml->__add_class(ctype_base::digit);
+            ++__first;
+            break;
+        case 's':
+            __ml = __start_matching_list(false);
+            __ml->__add_class(ctype_base::space);
+            ++__first;
+            break;
+        case 'S':
+            __ml = __start_matching_list(true);
+            __ml->__add_class(ctype_base::space);
+            ++__first;
+            break;
+        case 'w':
+            __ml = __start_matching_list(false);
+            __ml->__add_class(ctype_base::alnum);
+            __ml->__add_char('_');
+            ++__first;
+            break;
+        case 'W':
+            __ml = __start_matching_list(true);
+            __ml->__add_class(ctype_base::alnum);
+            __ml->__add_char('_');
+            ++__first;
+            break;
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_character_escape(_ForwardIterator __first,
+                                                    _ForwardIterator __last,
+                                                    basic_string<_CharT>* __str)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __t;
+        unsigned __sum = 0;
+        int __hd;
+        switch (*__first)
+        {
+        case 'f':
+            if (__str)
+                *__str = _CharT(0xC);
+            else
+                __push_char(_CharT(0xC));
+            ++__first;
+            break;
+        case 'n':
+            if (__str)
+                *__str = _CharT(0xA);
+            else
+                __push_char(_CharT(0xA));
+            ++__first;
+            break;
+        case 'r':
+            if (__str)
+                *__str = _CharT(0xD);
+            else
+                __push_char(_CharT(0xD));
+            ++__first;
+            break;
+        case 't':
+            if (__str)
+                *__str = _CharT(0x9);
+            else
+                __push_char(_CharT(0x9));
+            ++__first;
+            break;
+        case 'v':
+            if (__str)
+                *__str = _CharT(0xB);
+            else
+                __push_char(_CharT(0xB));
+            ++__first;
+            break;
+        case 'c':
+            if ((__t = _VSTD::next(__first)) != __last)
+            {
+                if (('A' <= *__t && *__t <= 'Z') ||
+                    ('a' <= *__t && *__t <= 'z'))
+                {
+                    if (__str)
+                        *__str = _CharT(*__t % 32);
+                    else
+                        __push_char(_CharT(*__t % 32));
+                    __first = ++__t;
+                }
+                else
+                    __throw_regex_error<regex_constants::error_escape>();
+            }
+            else
+                __throw_regex_error<regex_constants::error_escape>();
+            break;
+        case 'u':
+            ++__first;
+            if (__first == __last)
+                __throw_regex_error<regex_constants::error_escape>();
+            __hd = __traits_.value(*__first, 16);
+            if (__hd == -1)
+                __throw_regex_error<regex_constants::error_escape>();
+            __sum = 16 * __sum + static_cast<unsigned>(__hd);
+            ++__first;
+            if (__first == __last)
+                __throw_regex_error<regex_constants::error_escape>();
+            __hd = __traits_.value(*__first, 16);
+            if (__hd == -1)
+                __throw_regex_error<regex_constants::error_escape>();
+            __sum = 16 * __sum + static_cast<unsigned>(__hd);
+            // fallthrough
+        case 'x':
+            ++__first;
+            if (__first == __last)
+                __throw_regex_error<regex_constants::error_escape>();
+            __hd = __traits_.value(*__first, 16);
+            if (__hd == -1)
+                __throw_regex_error<regex_constants::error_escape>();
+            __sum = 16 * __sum + static_cast<unsigned>(__hd);
+            ++__first;
+            if (__first == __last)
+                __throw_regex_error<regex_constants::error_escape>();
+            __hd = __traits_.value(*__first, 16);
+            if (__hd == -1)
+                __throw_regex_error<regex_constants::error_escape>();
+            __sum = 16 * __sum + static_cast<unsigned>(__hd);
+            if (__str)
+                *__str = _CharT(__sum);
+            else
+                __push_char(_CharT(__sum));
+            ++__first;
+            break;
+        case '0':
+            if (__str)
+                *__str = _CharT(0);
+            else
+                __push_char(_CharT(0));
+            ++__first;
+            break;
+        default:
+            if (*__first != '_' && !__traits_.isctype(*__first, ctype_base::alnum))
+            {
+                if (__str)
+                    *__str = *__first;
+                else
+                    __push_char(*__first);
+                ++__first;
+            }
+            else
+                __throw_regex_error<regex_constants::error_escape>();
+            break;
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_pattern_character(_ForwardIterator __first,
+                                                        _ForwardIterator __last)
+{
+    if (__first != __last)
+    {
+        switch (*__first)
+        {
+        case '^':
+        case '$':
+        case '\\':
+        case '.':
+        case '*':
+        case '+':
+        case '?':
+        case '(':
+        case ')':
+        case '[':
+        case ']':
+        case '{':
+        case '}':
+        case '|':
+            break;
+        default:
+            __push_char(*__first);
+            ++__first;
+            break;
+        }
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_grep(_ForwardIterator __first,
+                                           _ForwardIterator __last)
+{
+    __owns_one_state<_CharT>* __sa = __end_;
+    _ForwardIterator __t1 = _VSTD::find(__first, __last, _CharT('\n'));
+    if (__t1 != __first)
+        __parse_basic_reg_exp(__first, __t1);
+    else
+        __push_empty();
+    __first = __t1;
+    if (__first != __last)
+        ++__first;
+    while (__first != __last)
+    {
+        __t1 = _VSTD::find(__first, __last, _CharT('\n'));
+        __owns_one_state<_CharT>* __sb = __end_;
+        if (__t1 != __first)
+            __parse_basic_reg_exp(__first, __t1);
+        else
+            __push_empty();
+        __push_alternation(__sa, __sb);
+        __first = __t1;
+        if (__first != __last)
+            ++__first;
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+template <class _ForwardIterator>
+_ForwardIterator
+basic_regex<_CharT, _Traits>::__parse_egrep(_ForwardIterator __first,
+                                            _ForwardIterator __last)
+{
+    __owns_one_state<_CharT>* __sa = __end_;
+    _ForwardIterator __t1 = _VSTD::find(__first, __last, _CharT('\n'));
+    if (__t1 != __first)
+        __parse_extended_reg_exp(__first, __t1);
+    else
+        __push_empty();
+    __first = __t1;
+    if (__first != __last)
+        ++__first;
+    while (__first != __last)
+    {
+        __t1 = _VSTD::find(__first, __last, _CharT('\n'));
+        __owns_one_state<_CharT>* __sb = __end_;
+        if (__t1 != __first)
+            __parse_extended_reg_exp(__first, __t1);
+        else
+            __push_empty();
+        __push_alternation(__sa, __sb);
+        __first = __t1;
+        if (__first != __last)
+            ++__first;
+    }
+    return __first;
+}
+
+template <class _CharT, class _Traits>
+bool
+basic_regex<_CharT, _Traits>::__test_back_ref(_CharT c)
+{
+    unsigned __val = __traits_.value(c, 10);
+    if (__val >= 1 && __val <= 9)
+    {
+        if (__val > mark_count())
+            __throw_regex_error<regex_constants::error_backref>();
+        __push_back_ref(__val);
+        return true;
+    }
+
+    return false;
+}
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::__push_loop(size_t __min, size_t __max,
+        __owns_one_state<_CharT>* __s, size_t __mexp_begin, size_t __mexp_end,
+        bool __greedy)
+{
+    unique_ptr<__empty_state<_CharT> > __e1(new __empty_state<_CharT>(__end_->first()));
+    __end_->first() = nullptr;
+    unique_ptr<__loop<_CharT> > __e2(new __loop<_CharT>(__loop_count_,
+                __s->first(), __e1.get(), __mexp_begin, __mexp_end, __greedy,
+                __min, __max));
+    __s->first() = nullptr;
+    __e1.release();
+    __end_->first() = new __repeat_one_loop<_CharT>(__e2.get());
+    __end_ = __e2->second();
+    __s->first() = __e2.release();
+    ++__loop_count_;
+}
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::__push_char(value_type __c)
+{
+    if (flags() & icase)
+        __end_->first() = new __match_char_icase<_CharT, _Traits>
+                                              (__traits_, __c, __end_->first());
+    else if (flags() & collate)
+        __end_->first() = new __match_char_collate<_CharT, _Traits>
+                                              (__traits_, __c, __end_->first());
+    else
+        __end_->first() = new __match_char<_CharT>(__c, __end_->first());
+    __end_ = static_cast<__owns_one_state<_CharT>*>(__end_->first());
+}
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::__push_begin_marked_subexpression()
+{
+    if (!(__flags_ & nosubs))
+    {
+        __end_->first() =
+                new __begin_marked_subexpression<_CharT>(++__marked_count_,
+                                                         __end_->first());
+        __end_ = static_cast<__owns_one_state<_CharT>*>(__end_->first());
+    }
+}
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::__push_end_marked_subexpression(unsigned __sub)
+{
+    if (!(__flags_ & nosubs))
+    {
+        __end_->first() =
+                new __end_marked_subexpression<_CharT>(__sub, __end_->first());
+        __end_ = static_cast<__owns_one_state<_CharT>*>(__end_->first());
+    }
+}
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::__push_l_anchor()
+{
+    __end_->first() = new __l_anchor_multiline<_CharT>(__use_multiline(), __end_->first());
+    __end_ = static_cast<__owns_one_state<_CharT>*>(__end_->first());
+}
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::__push_r_anchor()
+{
+    __end_->first() = new __r_anchor_multiline<_CharT>(__use_multiline(), __end_->first());
+    __end_ = static_cast<__owns_one_state<_CharT>*>(__end_->first());
+}
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::__push_match_any()
+{
+    __end_->first() = new __match_any<_CharT>(__end_->first());
+    __end_ = static_cast<__owns_one_state<_CharT>*>(__end_->first());
+}
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::__push_match_any_but_newline()
+{
+    __end_->first() = new __match_any_but_newline<_CharT>(__end_->first());
+    __end_ = static_cast<__owns_one_state<_CharT>*>(__end_->first());
+}
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::__push_empty()
+{
+    __end_->first() = new __empty_state<_CharT>(__end_->first());
+    __end_ = static_cast<__owns_one_state<_CharT>*>(__end_->first());
+}
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::__push_word_boundary(bool __invert)
+{
+    __end_->first() = new __word_boundary<_CharT, _Traits>(__traits_, __invert,
+                                                           __end_->first());
+    __end_ = static_cast<__owns_one_state<_CharT>*>(__end_->first());
+}
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::__push_back_ref(int __i)
+{
+    if (flags() & icase)
+        __end_->first() = new __back_ref_icase<_CharT, _Traits>
+                                              (__traits_, __i, __end_->first());
+    else if (flags() & collate)
+        __end_->first() = new __back_ref_collate<_CharT, _Traits>
+                                              (__traits_, __i, __end_->first());
+    else
+        __end_->first() = new __back_ref<_CharT>(__i, __end_->first());
+    __end_ = static_cast<__owns_one_state<_CharT>*>(__end_->first());
+}
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::__push_alternation(__owns_one_state<_CharT>* __sa,
+                                                 __owns_one_state<_CharT>* __ea)
+{
+    __sa->first() = new __alternate<_CharT>(
+                         static_cast<__owns_one_state<_CharT>*>(__sa->first()),
+                         static_cast<__owns_one_state<_CharT>*>(__ea->first()));
+    __ea->first() = nullptr;
+    __ea->first() = new __empty_state<_CharT>(__end_->first());
+    __end_->first() = nullptr;
+    __end_->first() = new __empty_non_own_state<_CharT>(__ea->first());
+    __end_ = static_cast<__owns_one_state<_CharT>*>(__ea->first());
+}
+
+template <class _CharT, class _Traits>
+__bracket_expression<_CharT, _Traits>*
+basic_regex<_CharT, _Traits>::__start_matching_list(bool __negate)
+{
+    __bracket_expression<_CharT, _Traits>* __r =
+        new __bracket_expression<_CharT, _Traits>(__traits_, __end_->first(),
+                                                  __negate, __flags_ & icase,
+                                                  __flags_ & collate);
+    __end_->first() = __r;
+    __end_ = __r;
+    return __r;
+}
+
+template <class _CharT, class _Traits>
+void
+basic_regex<_CharT, _Traits>::__push_lookahead(const basic_regex& __exp,
+                                               bool __invert,
+                                               unsigned __mexp)
+{
+    __end_->first() = new __lookahead<_CharT, _Traits>(__exp, __invert,
+                                                           __end_->first(), __mexp);
+    __end_ = static_cast<__owns_one_state<_CharT>*>(__end_->first());
+}
+
+// sub_match
+
+typedef sub_match<const char*>             csub_match;
+typedef sub_match<string::const_iterator>  ssub_match;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef sub_match<const wchar_t*>          wcsub_match;
+typedef sub_match<wstring::const_iterator> wssub_match;
+#endif
+
+template <class _BidirectionalIterator>
+class
+    _LIBCPP_TEMPLATE_VIS
+    _LIBCPP_PREFERRED_NAME(csub_match)
+    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wcsub_match))
+    _LIBCPP_PREFERRED_NAME(ssub_match)
+    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wssub_match))
+    sub_match
+    : public pair<_BidirectionalIterator, _BidirectionalIterator>
+{
+public:
+    typedef _BidirectionalIterator                              iterator;
+    typedef typename iterator_traits<iterator>::value_type      value_type;
+    typedef typename iterator_traits<iterator>::difference_type difference_type;
+    typedef basic_string<value_type>                            string_type;
+
+    bool matched;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR sub_match() : matched() {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    difference_type length() const
+        {return matched ? _VSTD::distance(this->first, this->second) : 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    string_type str() const
+        {return matched ? string_type(this->first, this->second) : string_type();}
+    _LIBCPP_INLINE_VISIBILITY
+    operator string_type() const
+        {return str();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    int compare(const sub_match& __s) const
+        {return str().compare(__s.str());}
+    _LIBCPP_INLINE_VISIBILITY
+    int compare(const string_type& __s) const
+        {return str().compare(__s);}
+    _LIBCPP_INLINE_VISIBILITY
+    int compare(const value_type* __s) const
+        {return str().compare(__s);}
+};
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const sub_match<_BiIter>& __x, const sub_match<_BiIter>& __y)
+{
+    return __x.compare(__y) == 0;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const sub_match<_BiIter>& __x, const sub_match<_BiIter>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(const sub_match<_BiIter>& __x, const sub_match<_BiIter>& __y)
+{
+    return __x.compare(__y) < 0;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const sub_match<_BiIter>& __x, const sub_match<_BiIter>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const sub_match<_BiIter>& __x, const sub_match<_BiIter>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>(const sub_match<_BiIter>& __x, const sub_match<_BiIter>& __y)
+{
+    return __y < __x;
+}
+
+template <class _BiIter, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const basic_string<typename iterator_traits<_BiIter>::value_type, _ST, _SA>& __x,
+           const sub_match<_BiIter>& __y)
+{
+    return __y.compare(typename sub_match<_BiIter>::string_type(__x.data(), __x.size())) == 0;
+}
+
+template <class _BiIter, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const basic_string<typename iterator_traits<_BiIter>::value_type, _ST, _SA>& __x,
+           const sub_match<_BiIter>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _BiIter, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(const basic_string<typename iterator_traits<_BiIter>::value_type, _ST, _SA>& __x,
+          const sub_match<_BiIter>& __y)
+{
+    return __y.compare(typename sub_match<_BiIter>::string_type(__x.data(), __x.size())) > 0;
+}
+
+template <class _BiIter, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>(const basic_string<typename iterator_traits<_BiIter>::value_type, _ST, _SA>& __x,
+          const sub_match<_BiIter>& __y)
+{
+    return __y < __x;
+}
+
+template <class _BiIter, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator>=(const basic_string<typename iterator_traits<_BiIter>::value_type, _ST, _SA>& __x,
+                const sub_match<_BiIter>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _BiIter, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const basic_string<typename iterator_traits<_BiIter>::value_type, _ST, _SA>& __x,
+           const sub_match<_BiIter>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _BiIter, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const sub_match<_BiIter>& __x,
+           const basic_string<typename iterator_traits<_BiIter>::value_type, _ST, _SA>& __y)
+{
+    return __x.compare(typename sub_match<_BiIter>::string_type(__y.data(), __y.size())) == 0;
+}
+
+template <class _BiIter, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const sub_match<_BiIter>& __x,
+           const basic_string<typename iterator_traits<_BiIter>::value_type, _ST, _SA>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _BiIter, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(const sub_match<_BiIter>& __x,
+          const basic_string<typename iterator_traits<_BiIter>::value_type, _ST, _SA>& __y)
+{
+    return __x.compare(typename sub_match<_BiIter>::string_type(__y.data(), __y.size())) < 0;
+}
+
+template <class _BiIter, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator>(const sub_match<_BiIter>& __x,
+               const basic_string<typename iterator_traits<_BiIter>::value_type, _ST, _SA>& __y)
+{
+    return __y < __x;
+}
+
+template <class _BiIter, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const sub_match<_BiIter>& __x,
+           const basic_string<typename iterator_traits<_BiIter>::value_type, _ST, _SA>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _BiIter, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const sub_match<_BiIter>& __x,
+           const basic_string<typename iterator_traits<_BiIter>::value_type, _ST, _SA>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(typename iterator_traits<_BiIter>::value_type const* __x,
+           const sub_match<_BiIter>& __y)
+{
+    return __y.compare(__x) == 0;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(typename iterator_traits<_BiIter>::value_type const* __x,
+           const sub_match<_BiIter>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(typename iterator_traits<_BiIter>::value_type const* __x,
+          const sub_match<_BiIter>& __y)
+{
+    return __y.compare(__x) > 0;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>(typename iterator_traits<_BiIter>::value_type const* __x,
+          const sub_match<_BiIter>& __y)
+{
+    return __y < __x;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(typename iterator_traits<_BiIter>::value_type const* __x,
+           const sub_match<_BiIter>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(typename iterator_traits<_BiIter>::value_type const* __x,
+           const sub_match<_BiIter>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const sub_match<_BiIter>& __x,
+           typename iterator_traits<_BiIter>::value_type const* __y)
+{
+    return __x.compare(__y) == 0;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const sub_match<_BiIter>& __x,
+           typename iterator_traits<_BiIter>::value_type const* __y)
+{
+    return !(__x == __y);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(const sub_match<_BiIter>& __x,
+          typename iterator_traits<_BiIter>::value_type const* __y)
+{
+    return __x.compare(__y) < 0;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>(const sub_match<_BiIter>& __x,
+          typename iterator_traits<_BiIter>::value_type const* __y)
+{
+    return __y < __x;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const sub_match<_BiIter>& __x,
+           typename iterator_traits<_BiIter>::value_type const* __y)
+{
+    return !(__x < __y);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const sub_match<_BiIter>& __x,
+           typename iterator_traits<_BiIter>::value_type const* __y)
+{
+    return !(__y < __x);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(typename iterator_traits<_BiIter>::value_type const& __x,
+           const sub_match<_BiIter>& __y)
+{
+    typedef basic_string<typename iterator_traits<_BiIter>::value_type> string_type;
+    return __y.compare(string_type(1, __x)) == 0;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(typename iterator_traits<_BiIter>::value_type const& __x,
+           const sub_match<_BiIter>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(typename iterator_traits<_BiIter>::value_type const& __x,
+          const sub_match<_BiIter>& __y)
+{
+    typedef basic_string<typename iterator_traits<_BiIter>::value_type> string_type;
+    return __y.compare(string_type(1, __x)) > 0;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>(typename iterator_traits<_BiIter>::value_type const& __x,
+          const sub_match<_BiIter>& __y)
+{
+    return __y < __x;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(typename iterator_traits<_BiIter>::value_type const& __x,
+           const sub_match<_BiIter>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(typename iterator_traits<_BiIter>::value_type const& __x,
+           const sub_match<_BiIter>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const sub_match<_BiIter>& __x,
+           typename iterator_traits<_BiIter>::value_type const& __y)
+{
+    typedef basic_string<typename iterator_traits<_BiIter>::value_type> string_type;
+    return __x.compare(string_type(1, __y)) == 0;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const sub_match<_BiIter>& __x,
+           typename iterator_traits<_BiIter>::value_type const& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(const sub_match<_BiIter>& __x,
+          typename iterator_traits<_BiIter>::value_type const& __y)
+{
+    typedef basic_string<typename iterator_traits<_BiIter>::value_type> string_type;
+    return __x.compare(string_type(1, __y)) < 0;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>(const sub_match<_BiIter>& __x,
+          typename iterator_traits<_BiIter>::value_type const& __y)
+{
+    return __y < __x;
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const sub_match<_BiIter>& __x,
+           typename iterator_traits<_BiIter>::value_type const& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const sub_match<_BiIter>& __x,
+           typename iterator_traits<_BiIter>::value_type const& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _CharT, class _ST, class _BiIter>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_ostream<_CharT, _ST>&
+operator<<(basic_ostream<_CharT, _ST>& __os, const sub_match<_BiIter>& __m)
+{
+    return __os << __m.str();
+}
+
+typedef match_results<const char*>             cmatch;
+typedef match_results<string::const_iterator>  smatch;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef match_results<const wchar_t*>          wcmatch;
+typedef match_results<wstring::const_iterator> wsmatch;
+#endif
+
+template <class _BidirectionalIterator, class _Allocator>
+class
+    _LIBCPP_TEMPLATE_VIS
+    _LIBCPP_PREFERRED_NAME(cmatch)
+    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wcmatch))
+    _LIBCPP_PREFERRED_NAME(smatch)
+    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wsmatch))
+    match_results
+{
+public:
+    typedef _Allocator                                        allocator_type;
+    typedef sub_match<_BidirectionalIterator>                 value_type;
+private:
+    typedef vector<value_type, allocator_type>                __container_type;
+
+    __container_type  __matches_;
+    value_type __unmatched_;
+    value_type __prefix_;
+    value_type __suffix_;
+    bool       __ready_;
+public:
+    _BidirectionalIterator __position_start_;
+    typedef const value_type&                                 const_reference;
+    typedef value_type&                                       reference;
+    typedef typename __container_type::const_iterator         const_iterator;
+    typedef const_iterator                                    iterator;
+    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
+    typedef typename allocator_traits<allocator_type>::size_type size_type;
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type char_type;
+    typedef basic_string<char_type>                           string_type;
+
+    // construct/copy/destroy:
+#ifndef _LIBCPP_CXX03_LANG
+    match_results() : match_results(allocator_type()) {}
+    explicit match_results(const allocator_type& __a);
+#else
+    explicit match_results(const allocator_type& __a = allocator_type());
+#endif
+
+//    match_results(const match_results&) = default;
+//    match_results& operator=(const match_results&) = default;
+//    match_results(match_results&& __m) = default;
+//    match_results& operator=(match_results&& __m) = default;
+//    ~match_results() = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool ready() const {return __ready_;}
+
+    // size:
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT {return __matches_.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT {return __matches_.max_size();}
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT {return size() == 0;}
+
+    // element access:
+    _LIBCPP_INLINE_VISIBILITY
+    difference_type length(size_type __sub = 0) const
+        {
+        _LIBCPP_ASSERT(ready(), "match_results::length() called when not ready");
+        return (*this)[__sub].length();
+        }
+    _LIBCPP_INLINE_VISIBILITY
+    difference_type position(size_type __sub = 0) const
+        {
+        _LIBCPP_ASSERT(ready(), "match_results::position() called when not ready");
+        return _VSTD::distance(__position_start_, (*this)[__sub].first);
+        }
+    _LIBCPP_INLINE_VISIBILITY
+    string_type str(size_type __sub = 0) const
+        {
+        _LIBCPP_ASSERT(ready(), "match_results::str() called when not ready");
+        return (*this)[__sub].str();
+        }
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference operator[](size_type __n) const
+        {
+        _LIBCPP_ASSERT(ready(), "match_results::operator[]() called when not ready");
+        return __n < __matches_.size() ? __matches_[__n] : __unmatched_;
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference prefix() const
+        {
+        _LIBCPP_ASSERT(ready(), "match_results::prefix() called when not ready");
+        return __prefix_;
+        }
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference suffix() const
+        {
+        _LIBCPP_ASSERT(ready(), "match_results::suffix() called when not ready");
+        return __suffix_;
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const {return empty() ? __matches_.end() : __matches_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end() const {return __matches_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin() const {return empty() ? __matches_.end() : __matches_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend() const {return __matches_.end();}
+
+    // format:
+    template <class _OutputIter>
+        _OutputIter
+        format(_OutputIter __output_iter, const char_type* __fmt_first,
+               const char_type* __fmt_last,
+               regex_constants::match_flag_type __flags = regex_constants::format_default) const;
+    template <class _OutputIter, class _ST, class _SA>
+        _LIBCPP_INLINE_VISIBILITY
+        _OutputIter
+        format(_OutputIter __output_iter, const basic_string<char_type, _ST, _SA>& __fmt,
+               regex_constants::match_flag_type __flags = regex_constants::format_default) const
+            {return format(__output_iter, __fmt.data(), __fmt.data() + __fmt.size(), __flags);}
+    template <class _ST, class _SA>
+        _LIBCPP_INLINE_VISIBILITY
+        basic_string<char_type, _ST, _SA>
+        format(const basic_string<char_type, _ST, _SA>& __fmt,
+               regex_constants::match_flag_type __flags = regex_constants::format_default) const
+        {
+            basic_string<char_type, _ST, _SA> __r;
+            format(back_inserter(__r), __fmt.data(), __fmt.data() + __fmt.size(),
+                   __flags);
+            return __r;
+        }
+    _LIBCPP_INLINE_VISIBILITY
+    string_type
+        format(const char_type* __fmt,
+               regex_constants::match_flag_type __flags = regex_constants::format_default) const
+        {
+            string_type __r;
+            format(back_inserter(__r), __fmt,
+                   __fmt + char_traits<char_type>::length(__fmt), __flags);
+            return __r;
+        }
+
+    // allocator:
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const {return __matches_.get_allocator();}
+
+    // swap:
+    void swap(match_results& __m);
+
+    template <class _Bp, class _Ap>
+        _LIBCPP_INLINE_VISIBILITY
+        void __assign(_BidirectionalIterator __f, _BidirectionalIterator __l,
+                      const match_results<_Bp, _Ap>& __m, bool __no_update_pos)
+    {
+        _Bp __mf = __m.prefix().first;
+        __matches_.resize(__m.size());
+        for (size_type __i = 0; __i < __matches_.size(); ++__i)
+        {
+            __matches_[__i].first = _VSTD::next(__f, _VSTD::distance(__mf, __m[__i].first));
+            __matches_[__i].second = _VSTD::next(__f, _VSTD::distance(__mf, __m[__i].second));
+            __matches_[__i].matched = __m[__i].matched;
+        }
+        __unmatched_.first   = __l;
+        __unmatched_.second  = __l;
+        __unmatched_.matched = false;
+        __prefix_.first = _VSTD::next(__f, _VSTD::distance(__mf, __m.prefix().first));
+        __prefix_.second = _VSTD::next(__f, _VSTD::distance(__mf, __m.prefix().second));
+        __prefix_.matched = __m.prefix().matched;
+        __suffix_.first = _VSTD::next(__f, _VSTD::distance(__mf, __m.suffix().first));
+        __suffix_.second = _VSTD::next(__f, _VSTD::distance(__mf, __m.suffix().second));
+        __suffix_.matched = __m.suffix().matched;
+        if (!__no_update_pos)
+            __position_start_ = __prefix_.first;
+        __ready_ = __m.ready();
+    }
+
+private:
+    void __init(unsigned __s,
+                _BidirectionalIterator __f, _BidirectionalIterator __l,
+                bool __no_update_pos = false);
+
+    template <class, class> friend class basic_regex;
+
+    template <class _Bp, class _Ap, class _Cp, class _Tp>
+    friend
+    bool
+    regex_match(_Bp, _Bp, match_results<_Bp, _Ap>&, const basic_regex<_Cp, _Tp>&,
+                regex_constants::match_flag_type);
+
+    template <class _Bp, class _Ap>
+    friend
+    bool
+    operator==(const match_results<_Bp, _Ap>&, const match_results<_Bp, _Ap>&);
+
+    template <class, class> friend class __lookahead;
+};
+
+template <class _BidirectionalIterator, class _Allocator>
+match_results<_BidirectionalIterator, _Allocator>::match_results(
+        const allocator_type& __a)
+    : __matches_(__a),
+      __unmatched_(),
+      __prefix_(),
+      __suffix_(),
+      __ready_(false),
+      __position_start_()
+{
+}
+
+template <class _BidirectionalIterator, class _Allocator>
+void
+match_results<_BidirectionalIterator, _Allocator>::__init(unsigned __s,
+                         _BidirectionalIterator __f, _BidirectionalIterator __l,
+                         bool __no_update_pos)
+{
+    __unmatched_.first   = __l;
+    __unmatched_.second  = __l;
+    __unmatched_.matched = false;
+    __matches_.assign(__s, __unmatched_);
+    __prefix_.first      = __f;
+    __prefix_.second     = __f;
+    __prefix_.matched    = false;
+    __suffix_ = __unmatched_;
+    if (!__no_update_pos)
+        __position_start_ = __prefix_.first;
+    __ready_ = true;
+}
+
+template <class _BidirectionalIterator, class _Allocator>
+template <class _OutputIter>
+_OutputIter
+match_results<_BidirectionalIterator, _Allocator>::format(_OutputIter __output_iter,
+        const char_type* __fmt_first, const char_type* __fmt_last,
+        regex_constants::match_flag_type __flags) const
+{
+    _LIBCPP_ASSERT(ready(), "match_results::format() called when not ready");
+    if (__flags & regex_constants::format_sed)
+    {
+        for (; __fmt_first != __fmt_last; ++__fmt_first)
+        {
+            if (*__fmt_first == '&')
+                __output_iter = _VSTD::copy(__matches_[0].first, __matches_[0].second,
+                                   __output_iter);
+            else if (*__fmt_first == '\\' && __fmt_first + 1 != __fmt_last)
+            {
+                ++__fmt_first;
+                if ('0' <= *__fmt_first && *__fmt_first <= '9')
+                {
+                    size_t __i = *__fmt_first - '0';
+                    __output_iter = _VSTD::copy((*this)[__i].first,
+                                        (*this)[__i].second, __output_iter);
+                }
+                else
+                {
+                    *__output_iter = *__fmt_first;
+                    ++__output_iter;
+                }
+            }
+            else
+            {
+                *__output_iter = *__fmt_first;
+                ++__output_iter;
+            }
+        }
+    }
+    else
+    {
+        for (; __fmt_first != __fmt_last; ++__fmt_first)
+        {
+            if (*__fmt_first == '$' && __fmt_first + 1 != __fmt_last)
+            {
+                switch (__fmt_first[1])
+                {
+                case '$':
+                    *__output_iter = *++__fmt_first;
+                    ++__output_iter;
+                    break;
+                case '&':
+                    ++__fmt_first;
+                    __output_iter = _VSTD::copy(__matches_[0].first, __matches_[0].second,
+                                       __output_iter);
+                    break;
+                case '`':
+                    ++__fmt_first;
+                    __output_iter = _VSTD::copy(__prefix_.first, __prefix_.second, __output_iter);
+                    break;
+                case '\'':
+                    ++__fmt_first;
+                    __output_iter = _VSTD::copy(__suffix_.first, __suffix_.second, __output_iter);
+                    break;
+                default:
+                    if ('0' <= __fmt_first[1] && __fmt_first[1] <= '9')
+                    {
+                        ++__fmt_first;
+                        size_t __idx = *__fmt_first - '0';
+                        if (__fmt_first + 1 != __fmt_last &&
+                            '0' <= __fmt_first[1] && __fmt_first[1] <= '9')
+                        {
+                            ++__fmt_first;
+                            if (__idx >= numeric_limits<size_t>::max() / 10)
+                                __throw_regex_error<regex_constants::error_escape>();
+                            __idx = 10 * __idx + *__fmt_first - '0';
+                        }
+                        __output_iter = _VSTD::copy((*this)[__idx].first,
+                                            (*this)[__idx].second, __output_iter);
+                    }
+                    else
+                    {
+                        *__output_iter = *__fmt_first;
+                        ++__output_iter;
+                    }
+                    break;
+                }
+            }
+            else
+            {
+                *__output_iter = *__fmt_first;
+                ++__output_iter;
+            }
+        }
+    }
+    return __output_iter;
+}
+
+template <class _BidirectionalIterator, class _Allocator>
+void
+match_results<_BidirectionalIterator, _Allocator>::swap(match_results& __m)
+{
+    using _VSTD::swap;
+    swap(__matches_, __m.__matches_);
+    swap(__unmatched_, __m.__unmatched_);
+    swap(__prefix_, __m.__prefix_);
+    swap(__suffix_, __m.__suffix_);
+    swap(__position_start_, __m.__position_start_);
+    swap(__ready_, __m.__ready_);
+}
+
+template <class _BidirectionalIterator, class _Allocator>
+bool
+operator==(const match_results<_BidirectionalIterator, _Allocator>& __x,
+           const match_results<_BidirectionalIterator, _Allocator>& __y)
+{
+    if (__x.__ready_ != __y.__ready_)
+        return false;
+    if (!__x.__ready_)
+        return true;
+    return __x.__matches_ == __y.__matches_ &&
+           __x.__prefix_ == __y.__prefix_ &&
+           __x.__suffix_ == __y.__suffix_;
+}
+
+template <class _BidirectionalIterator, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const match_results<_BidirectionalIterator, _Allocator>& __x,
+           const match_results<_BidirectionalIterator, _Allocator>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _BidirectionalIterator, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(match_results<_BidirectionalIterator, _Allocator>& __x,
+     match_results<_BidirectionalIterator, _Allocator>& __y)
+{
+    __x.swap(__y);
+}
+
+// regex_search
+
+template <class _CharT, class _Traits>
+template <class _Allocator>
+bool
+basic_regex<_CharT, _Traits>::__match_at_start_ecma(
+        const _CharT* __first, const _CharT* __last,
+        match_results<const _CharT*, _Allocator>& __m,
+        regex_constants::match_flag_type __flags, bool __at_first) const
+{
+    vector<__state> __states;
+    __node* __st = __start_.get();
+    if (__st)
+    {
+        sub_match<const _CharT*> __unmatched;
+        __unmatched.first   = __last;
+        __unmatched.second  = __last;
+        __unmatched.matched = false;
+
+        __states.push_back(__state());
+        __states.back().__do_ = 0;
+        __states.back().__first_ = __first;
+        __states.back().__current_ = __first;
+        __states.back().__last_ = __last;
+        __states.back().__sub_matches_.resize(mark_count(), __unmatched);
+        __states.back().__loop_data_.resize(__loop_count());
+        __states.back().__node_ = __st;
+        __states.back().__flags_ = __flags;
+        __states.back().__at_first_ = __at_first;
+        int __counter = 0;
+        int __length = __last - __first;
+        do
+        {
+            ++__counter;
+            if (__counter % _LIBCPP_REGEX_COMPLEXITY_FACTOR == 0 &&
+                __counter / _LIBCPP_REGEX_COMPLEXITY_FACTOR >= __length)
+              __throw_regex_error<regex_constants::error_complexity>();
+            __state& __s = __states.back();
+            if (__s.__node_)
+                __s.__node_->__exec(__s);
+            switch (__s.__do_)
+            {
+            case __state::__end_state:
+                if ((__flags & regex_constants::match_not_null) &&
+                    __s.__current_ == __first)
+                {
+                  __states.pop_back();
+                  break;
+                }
+                if ((__flags & regex_constants::__full_match) &&
+                    __s.__current_ != __last)
+                {
+                  __states.pop_back();
+                  break;
+                }
+                __m.__matches_[0].first = __first;
+                __m.__matches_[0].second = _VSTD::next(__first, __s.__current_ - __first);
+                __m.__matches_[0].matched = true;
+                for (unsigned __i = 0; __i < __s.__sub_matches_.size(); ++__i)
+                    __m.__matches_[__i+1] = __s.__sub_matches_[__i];
+                return true;
+            case __state::__accept_and_consume:
+            case __state::__repeat:
+            case __state::__accept_but_not_consume:
+                break;
+            case __state::__split:
+                {
+                __state __snext = __s;
+                __s.__node_->__exec_split(true, __s);
+                __snext.__node_->__exec_split(false, __snext);
+                __states.push_back(_VSTD::move(__snext));
+                }
+                break;
+            case __state::__reject:
+                __states.pop_back();
+                break;
+            default:
+                __throw_regex_error<regex_constants::__re_err_unknown>();
+                break;
+
+            }
+        } while (!__states.empty());
+    }
+    return false;
+}
+
+template <class _CharT, class _Traits>
+template <class _Allocator>
+bool
+basic_regex<_CharT, _Traits>::__match_at_start_posix_nosubs(
+        const _CharT* __first, const _CharT* __last,
+        match_results<const _CharT*, _Allocator>& __m,
+        regex_constants::match_flag_type __flags, bool __at_first) const
+{
+    deque<__state> __states;
+    ptrdiff_t __highest_j = 0;
+    ptrdiff_t _Np = _VSTD::distance(__first, __last);
+    __node* __st = __start_.get();
+    if (__st)
+    {
+        __states.push_back(__state());
+        __states.back().__do_ = 0;
+        __states.back().__first_ = __first;
+        __states.back().__current_ = __first;
+        __states.back().__last_ = __last;
+        __states.back().__loop_data_.resize(__loop_count());
+        __states.back().__node_ = __st;
+        __states.back().__flags_ = __flags;
+        __states.back().__at_first_ = __at_first;
+        bool __matched = false;
+        int __counter = 0;
+        int __length = __last - __first;
+        do
+        {
+            ++__counter;
+            if (__counter % _LIBCPP_REGEX_COMPLEXITY_FACTOR == 0 &&
+                __counter / _LIBCPP_REGEX_COMPLEXITY_FACTOR >= __length)
+              __throw_regex_error<regex_constants::error_complexity>();
+            __state& __s = __states.back();
+            if (__s.__node_)
+                __s.__node_->__exec(__s);
+            switch (__s.__do_)
+            {
+            case __state::__end_state:
+                if ((__flags & regex_constants::match_not_null) &&
+                    __s.__current_ == __first)
+                {
+                  __states.pop_back();
+                  break;
+                }
+                if ((__flags & regex_constants::__full_match) &&
+                    __s.__current_ != __last)
+                {
+                  __states.pop_back();
+                  break;
+                }
+                if (!__matched || __highest_j < __s.__current_ - __s.__first_)
+                    __highest_j = __s.__current_ - __s.__first_;
+                __matched = true;
+                if (__highest_j == _Np)
+                    __states.clear();
+                else
+                    __states.pop_back();
+                break;
+            case __state::__consume_input:
+                break;
+            case __state::__accept_and_consume:
+                __states.push_front(_VSTD::move(__s));
+                __states.pop_back();
+                break;
+            case __state::__repeat:
+            case __state::__accept_but_not_consume:
+                break;
+            case __state::__split:
+                {
+                __state __snext = __s;
+                __s.__node_->__exec_split(true, __s);
+                __snext.__node_->__exec_split(false, __snext);
+                __states.push_back(_VSTD::move(__snext));
+                }
+                break;
+            case __state::__reject:
+                __states.pop_back();
+                break;
+            default:
+                __throw_regex_error<regex_constants::__re_err_unknown>();
+                break;
+            }
+        } while (!__states.empty());
+        if (__matched)
+        {
+            __m.__matches_[0].first = __first;
+            __m.__matches_[0].second = _VSTD::next(__first, __highest_j);
+            __m.__matches_[0].matched = true;
+            return true;
+        }
+    }
+    return false;
+}
+
+template <class _CharT, class _Traits>
+template <class _Allocator>
+bool
+basic_regex<_CharT, _Traits>::__match_at_start_posix_subs(
+        const _CharT* __first, const _CharT* __last,
+        match_results<const _CharT*, _Allocator>& __m,
+        regex_constants::match_flag_type __flags, bool __at_first) const
+{
+    vector<__state> __states;
+    __state __best_state;
+    ptrdiff_t __highest_j = 0;
+    ptrdiff_t _Np = _VSTD::distance(__first, __last);
+    __node* __st = __start_.get();
+    if (__st)
+    {
+        sub_match<const _CharT*> __unmatched;
+        __unmatched.first   = __last;
+        __unmatched.second  = __last;
+        __unmatched.matched = false;
+
+        __states.push_back(__state());
+        __states.back().__do_ = 0;
+        __states.back().__first_ = __first;
+        __states.back().__current_ = __first;
+        __states.back().__last_ = __last;
+        __states.back().__sub_matches_.resize(mark_count(), __unmatched);
+        __states.back().__loop_data_.resize(__loop_count());
+        __states.back().__node_ = __st;
+        __states.back().__flags_ = __flags;
+        __states.back().__at_first_ = __at_first;
+        bool __matched = false;
+        int __counter = 0;
+        int __length = __last - __first;
+        do
+        {
+            ++__counter;
+            if (__counter % _LIBCPP_REGEX_COMPLEXITY_FACTOR == 0 &&
+                __counter / _LIBCPP_REGEX_COMPLEXITY_FACTOR >= __length)
+              __throw_regex_error<regex_constants::error_complexity>();
+            __state& __s = __states.back();
+            if (__s.__node_)
+                __s.__node_->__exec(__s);
+            switch (__s.__do_)
+            {
+            case __state::__end_state:
+                if ((__flags & regex_constants::match_not_null) &&
+                    __s.__current_ == __first)
+                {
+                  __states.pop_back();
+                  break;
+                }
+                if ((__flags & regex_constants::__full_match) &&
+                    __s.__current_ != __last)
+                {
+                  __states.pop_back();
+                  break;
+                }
+                if (!__matched || __highest_j < __s.__current_ - __s.__first_)
+                {
+                    __highest_j = __s.__current_ - __s.__first_;
+                    __best_state = __s;
+                }
+                __matched = true;
+                if (__highest_j == _Np)
+                    __states.clear();
+                else
+                    __states.pop_back();
+                break;
+            case __state::__accept_and_consume:
+            case __state::__repeat:
+            case __state::__accept_but_not_consume:
+                break;
+            case __state::__split:
+                {
+                __state __snext = __s;
+                __s.__node_->__exec_split(true, __s);
+                __snext.__node_->__exec_split(false, __snext);
+                __states.push_back(_VSTD::move(__snext));
+                }
+                break;
+            case __state::__reject:
+                __states.pop_back();
+                break;
+            default:
+                __throw_regex_error<regex_constants::__re_err_unknown>();
+                break;
+            }
+        } while (!__states.empty());
+        if (__matched)
+        {
+            __m.__matches_[0].first = __first;
+            __m.__matches_[0].second = _VSTD::next(__first, __highest_j);
+            __m.__matches_[0].matched = true;
+            for (unsigned __i = 0; __i < __best_state.__sub_matches_.size(); ++__i)
+                __m.__matches_[__i+1] = __best_state.__sub_matches_[__i];
+            return true;
+        }
+    }
+    return false;
+}
+
+template <class _CharT, class _Traits>
+template <class _Allocator>
+bool
+basic_regex<_CharT, _Traits>::__match_at_start(
+        const _CharT* __first, const _CharT* __last,
+        match_results<const _CharT*, _Allocator>& __m,
+        regex_constants::match_flag_type __flags, bool __at_first) const
+{
+    if (__get_grammar(__flags_) == ECMAScript)
+        return __match_at_start_ecma(__first, __last, __m, __flags, __at_first);
+    if (mark_count() == 0)
+        return __match_at_start_posix_nosubs(__first, __last, __m, __flags, __at_first);
+    return __match_at_start_posix_subs(__first, __last, __m, __flags, __at_first);
+}
+
+template <class _CharT, class _Traits>
+template <class _Allocator>
+bool
+basic_regex<_CharT, _Traits>::__search(
+        const _CharT* __first, const _CharT* __last,
+        match_results<const _CharT*, _Allocator>& __m,
+        regex_constants::match_flag_type __flags) const
+{
+    if (__flags & regex_constants::match_prev_avail)
+        __flags &= ~(regex_constants::match_not_bol | regex_constants::match_not_bow);
+
+    __m.__init(1 + mark_count(), __first, __last,
+                                    __flags & regex_constants::__no_update_pos);
+    if (__match_at_start(__first, __last, __m, __flags,
+                                    !(__flags & regex_constants::__no_update_pos)))
+    {
+        __m.__prefix_.second = __m[0].first;
+        __m.__prefix_.matched = __m.__prefix_.first != __m.__prefix_.second;
+        __m.__suffix_.first = __m[0].second;
+        __m.__suffix_.matched = __m.__suffix_.first != __m.__suffix_.second;
+        return true;
+    }
+    if (__first != __last && !(__flags & regex_constants::match_continuous))
+    {
+        __flags |= regex_constants::match_prev_avail;
+        for (++__first; __first != __last; ++__first)
+        {
+            __m.__matches_.assign(__m.size(), __m.__unmatched_);
+            if (__match_at_start(__first, __last, __m, __flags, false))
+            {
+                __m.__prefix_.second = __m[0].first;
+                __m.__prefix_.matched = __m.__prefix_.first != __m.__prefix_.second;
+                __m.__suffix_.first = __m[0].second;
+                __m.__suffix_.matched = __m.__suffix_.first != __m.__suffix_.second;
+                return true;
+            }
+            __m.__matches_.assign(__m.size(), __m.__unmatched_);
+        }
+    }
+    __m.__matches_.clear();
+    return false;
+}
+
+template <class _BidirectionalIterator, class _Allocator, class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_search(_BidirectionalIterator __first, _BidirectionalIterator __last,
+             match_results<_BidirectionalIterator, _Allocator>& __m,
+             const basic_regex<_CharT, _Traits>& __e,
+             regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    int __offset = (__flags & regex_constants::match_prev_avail) ? 1 : 0;
+    basic_string<_CharT> __s(_VSTD::prev(__first, __offset), __last);
+    match_results<const _CharT*> __mc;
+    bool __r = __e.__search(__s.data() + __offset, __s.data() + __s.size(), __mc, __flags);
+    __m.__assign(__first, __last, __mc, __flags & regex_constants::__no_update_pos);
+    return __r;
+}
+
+template <class _Iter, class _Allocator, class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_search(__wrap_iter<_Iter> __first,
+             __wrap_iter<_Iter> __last,
+             match_results<__wrap_iter<_Iter>, _Allocator>& __m,
+             const basic_regex<_CharT, _Traits>& __e,
+             regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    match_results<const _CharT*> __mc;
+    bool __r = __e.__search(__first.base(), __last.base(), __mc, __flags);
+    __m.__assign(__first, __last, __mc, __flags & regex_constants::__no_update_pos);
+    return __r;
+}
+
+template <class _Allocator, class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_search(const _CharT* __first, const _CharT* __last,
+             match_results<const _CharT*, _Allocator>& __m,
+             const basic_regex<_CharT, _Traits>& __e,
+             regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    return __e.__search(__first, __last, __m, __flags);
+}
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_search(_BidirectionalIterator __first, _BidirectionalIterator __last,
+             const basic_regex<_CharT, _Traits>& __e,
+             regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    basic_string<_CharT> __s(__first, __last);
+    match_results<const _CharT*> __mc;
+    return __e.__search(__s.data(), __s.data() + __s.size(), __mc, __flags);
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_search(const _CharT* __first, const _CharT* __last,
+             const basic_regex<_CharT, _Traits>& __e,
+             regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    match_results<const _CharT*> __mc;
+    return __e.__search(__first, __last, __mc, __flags);
+}
+
+template <class _CharT, class _Allocator, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_search(const _CharT* __str, match_results<const _CharT*, _Allocator>& __m,
+             const basic_regex<_CharT, _Traits>& __e,
+             regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    return __e.__search(__str, __str + _Traits::length(__str), __m, __flags);
+}
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_search(const _CharT* __str, const basic_regex<_CharT, _Traits>& __e,
+             regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    match_results<const _CharT*> __m;
+    return _VSTD::regex_search(__str, __m, __e, __flags);
+}
+
+template <class _ST, class _SA, class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_search(const basic_string<_CharT, _ST, _SA>& __s,
+             const basic_regex<_CharT, _Traits>& __e,
+             regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    match_results<const _CharT*> __mc;
+    return __e.__search(__s.data(), __s.data() + __s.size(), __mc, __flags);
+}
+
+template <class _ST, class _SA, class _Allocator, class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_search(const basic_string<_CharT, _ST, _SA>& __s,
+             match_results<typename basic_string<_CharT, _ST, _SA>::const_iterator, _Allocator>& __m,
+             const basic_regex<_CharT, _Traits>& __e,
+             regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    match_results<const _CharT*> __mc;
+    bool __r = __e.__search(__s.data(), __s.data() + __s.size(), __mc, __flags);
+    __m.__assign(__s.begin(), __s.end(), __mc, __flags & regex_constants::__no_update_pos);
+    return __r;
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _ST, class _SA, class _Ap, class _Cp, class _Tp>
+bool
+regex_search(const basic_string<_Cp, _ST, _SA>&& __s,
+             match_results<typename basic_string<_Cp, _ST, _SA>::const_iterator, _Ap>&,
+             const basic_regex<_Cp, _Tp>& __e,
+             regex_constants::match_flag_type __flags = regex_constants::match_default) = delete;
+#endif
+
+// regex_match
+
+template <class _BidirectionalIterator, class _Allocator, class _CharT, class _Traits>
+bool
+regex_match(_BidirectionalIterator __first, _BidirectionalIterator __last,
+            match_results<_BidirectionalIterator, _Allocator>& __m,
+            const basic_regex<_CharT, _Traits>& __e,
+            regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    bool __r = _VSTD::regex_search(
+        __first, __last, __m, __e,
+        __flags | regex_constants::match_continuous |
+        regex_constants::__full_match);
+    if (__r)
+    {
+        __r = !__m.suffix().matched;
+        if (!__r)
+            __m.__matches_.clear();
+    }
+    return __r;
+}
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_match(_BidirectionalIterator __first, _BidirectionalIterator __last,
+            const basic_regex<_CharT, _Traits>& __e,
+            regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    match_results<_BidirectionalIterator> __m;
+    return _VSTD::regex_match(__first, __last, __m, __e, __flags);
+}
+
+template <class _CharT, class _Allocator, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_match(const _CharT* __str, match_results<const _CharT*, _Allocator>& __m,
+            const basic_regex<_CharT, _Traits>& __e,
+            regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    return _VSTD::regex_match(__str, __str + _Traits::length(__str), __m, __e, __flags);
+}
+
+template <class _ST, class _SA, class _Allocator, class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_match(const basic_string<_CharT, _ST, _SA>& __s,
+            match_results<typename basic_string<_CharT, _ST, _SA>::const_iterator, _Allocator>& __m,
+            const basic_regex<_CharT, _Traits>& __e,
+            regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    return _VSTD::regex_match(__s.begin(), __s.end(), __m, __e, __flags);
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _ST, class _SA, class _Allocator, class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_match(const basic_string<_CharT, _ST, _SA>&& __s,
+            match_results<typename basic_string<_CharT, _ST, _SA>::const_iterator, _Allocator>& __m,
+            const basic_regex<_CharT, _Traits>& __e,
+            regex_constants::match_flag_type __flags = regex_constants::match_default) = delete;
+#endif
+
+template <class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_match(const _CharT* __str, const basic_regex<_CharT, _Traits>& __e,
+            regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    return _VSTD::regex_match(__str, __str + _Traits::length(__str), __e, __flags);
+}
+
+template <class _ST, class _SA, class _CharT, class _Traits>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+regex_match(const basic_string<_CharT, _ST, _SA>& __s,
+            const basic_regex<_CharT, _Traits>& __e,
+            regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    return _VSTD::regex_match(__s.begin(), __s.end(), __e, __flags);
+}
+
+// regex_iterator
+
+template <class _BidirectionalIterator,
+          class _CharT = typename iterator_traits<_BidirectionalIterator>::value_type,
+          class _Traits = regex_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS regex_iterator;
+
+typedef regex_iterator<const char*>             cregex_iterator;
+typedef regex_iterator<string::const_iterator>  sregex_iterator;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef regex_iterator<const wchar_t*>          wcregex_iterator;
+typedef regex_iterator<wstring::const_iterator> wsregex_iterator;
+#endif
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+class
+    _LIBCPP_TEMPLATE_VIS
+    _LIBCPP_PREFERRED_NAME(cregex_iterator)
+    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wcregex_iterator))
+    _LIBCPP_PREFERRED_NAME(sregex_iterator)
+    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wsregex_iterator))
+    regex_iterator
+{
+public:
+    typedef basic_regex<_CharT, _Traits>          regex_type;
+    typedef match_results<_BidirectionalIterator> value_type;
+    typedef ptrdiff_t                             difference_type;
+    typedef const value_type*                     pointer;
+    typedef const value_type&                     reference;
+    typedef forward_iterator_tag                  iterator_category;
+
+private:
+    _BidirectionalIterator           __begin_;
+    _BidirectionalIterator           __end_;
+    const regex_type*                __pregex_;
+    regex_constants::match_flag_type __flags_;
+    value_type                       __match_;
+
+public:
+    regex_iterator();
+    regex_iterator(_BidirectionalIterator __a, _BidirectionalIterator __b,
+                   const regex_type& __re,
+                   regex_constants::match_flag_type __m
+                                              = regex_constants::match_default);
+#if _LIBCPP_STD_VER > 11
+    regex_iterator(_BidirectionalIterator __a, _BidirectionalIterator __b,
+                   const regex_type&& __re,
+                   regex_constants::match_flag_type __m
+                                     = regex_constants::match_default) = delete;
+#endif
+
+    bool operator==(const regex_iterator& __x) const;
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const regex_iterator& __x) const {return !(*this == __x);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {return  __match_;}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const  {return _VSTD::addressof(__match_);}
+
+    regex_iterator& operator++();
+    _LIBCPP_INLINE_VISIBILITY
+    regex_iterator operator++(int)
+    {
+        regex_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+};
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+regex_iterator<_BidirectionalIterator, _CharT, _Traits>::regex_iterator()
+    : __begin_(), __end_(), __pregex_(nullptr), __flags_(), __match_()
+{
+}
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+regex_iterator<_BidirectionalIterator, _CharT, _Traits>::
+    regex_iterator(_BidirectionalIterator __a, _BidirectionalIterator __b,
+                   const regex_type& __re, regex_constants::match_flag_type __m)
+    : __begin_(__a),
+      __end_(__b),
+      __pregex_(_VSTD::addressof(__re)),
+      __flags_(__m)
+{
+    _VSTD::regex_search(__begin_, __end_, __match_, *__pregex_, __flags_);
+}
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+bool
+regex_iterator<_BidirectionalIterator, _CharT, _Traits>::
+    operator==(const regex_iterator& __x) const
+{
+    if (__match_.empty() && __x.__match_.empty())
+        return true;
+    if (__match_.empty() || __x.__match_.empty())
+        return false;
+    return __begin_ == __x.__begin_       &&
+           __end_ == __x.__end_           &&
+           __pregex_ == __x.__pregex_     &&
+           __flags_ == __x.__flags_       &&
+           __match_[0] == __x.__match_[0];
+}
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+regex_iterator<_BidirectionalIterator, _CharT, _Traits>&
+regex_iterator<_BidirectionalIterator, _CharT, _Traits>::operator++()
+{
+    __flags_ |= regex_constants::__no_update_pos;
+    _BidirectionalIterator __start = __match_[0].second;
+    if (__match_[0].first == __match_[0].second)
+    {
+        if (__start == __end_)
+        {
+            __match_ = value_type();
+            return *this;
+        }
+        else if (_VSTD::regex_search(__start, __end_, __match_, *__pregex_,
+                                    __flags_ | regex_constants::match_not_null |
+                                    regex_constants::match_continuous))
+            return *this;
+        else
+            ++__start;
+    }
+    __flags_ |= regex_constants::match_prev_avail;
+    if (!_VSTD::regex_search(__start, __end_, __match_, *__pregex_, __flags_))
+        __match_ = value_type();
+    return *this;
+}
+
+// regex_token_iterator
+
+template <class _BidirectionalIterator,
+          class _CharT = typename iterator_traits<_BidirectionalIterator>::value_type,
+          class _Traits = regex_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS regex_token_iterator;
+
+typedef regex_token_iterator<const char*>             cregex_token_iterator;
+typedef regex_token_iterator<string::const_iterator>  sregex_token_iterator;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef regex_token_iterator<const wchar_t*>          wcregex_token_iterator;
+typedef regex_token_iterator<wstring::const_iterator> wsregex_token_iterator;
+#endif
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+class
+    _LIBCPP_TEMPLATE_VIS
+    _LIBCPP_PREFERRED_NAME(cregex_token_iterator)
+    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wcregex_token_iterator))
+    _LIBCPP_PREFERRED_NAME(sregex_token_iterator)
+    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wsregex_token_iterator))
+    regex_token_iterator
+{
+public:
+    typedef basic_regex<_CharT, _Traits>      regex_type;
+    typedef sub_match<_BidirectionalIterator> value_type;
+    typedef ptrdiff_t                         difference_type;
+    typedef const value_type*                 pointer;
+    typedef const value_type&                 reference;
+    typedef forward_iterator_tag              iterator_category;
+
+private:
+    typedef regex_iterator<_BidirectionalIterator, _CharT, _Traits> _Position;
+
+    _Position         __position_;
+    const value_type* __result_;
+    value_type        __suffix_;
+    ptrdiff_t         __n_;
+    vector<int>       __subs_;
+
+public:
+    regex_token_iterator();
+    regex_token_iterator(_BidirectionalIterator __a, _BidirectionalIterator __b,
+                         const regex_type& __re, int __submatch = 0,
+                         regex_constants::match_flag_type __m =
+                                                regex_constants::match_default);
+#if _LIBCPP_STD_VER > 11
+    regex_token_iterator(_BidirectionalIterator __a, _BidirectionalIterator __b,
+                         const regex_type&& __re, int __submatch = 0,
+                         regex_constants::match_flag_type __m =
+                                       regex_constants::match_default) = delete;
+#endif
+
+    regex_token_iterator(_BidirectionalIterator __a, _BidirectionalIterator __b,
+                         const regex_type& __re, const vector<int>& __submatches,
+                         regex_constants::match_flag_type __m =
+                                                regex_constants::match_default);
+#if _LIBCPP_STD_VER > 11
+    regex_token_iterator(_BidirectionalIterator __a, _BidirectionalIterator __b,
+                         const regex_type&& __re, const vector<int>& __submatches,
+                         regex_constants::match_flag_type __m =
+                                     regex_constants::match_default) = delete;
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+    regex_token_iterator(_BidirectionalIterator __a, _BidirectionalIterator __b,
+                         const regex_type& __re,
+                         initializer_list<int> __submatches,
+                         regex_constants::match_flag_type __m =
+                                                regex_constants::match_default);
+
+#if _LIBCPP_STD_VER > 11
+    regex_token_iterator(_BidirectionalIterator __a, _BidirectionalIterator __b,
+                         const regex_type&& __re,
+                         initializer_list<int> __submatches,
+                         regex_constants::match_flag_type __m =
+                                       regex_constants::match_default) = delete;
+#endif
+#endif // _LIBCPP_CXX03_LANG
+    template <size_t _Np>
+        regex_token_iterator(_BidirectionalIterator __a,
+                             _BidirectionalIterator __b,
+                             const regex_type& __re,
+                             const int (&__submatches)[_Np],
+                             regex_constants::match_flag_type __m =
+                                                regex_constants::match_default);
+#if _LIBCPP_STD_VER > 11
+    template <size_t _Np>
+        regex_token_iterator(_BidirectionalIterator __a,
+                             _BidirectionalIterator __b,
+                             const regex_type&& __re,
+                             const int (&__submatches)[_Np],
+                             regex_constants::match_flag_type __m =
+                                      regex_constants::match_default) = delete;
+#endif
+
+    regex_token_iterator(const regex_token_iterator&);
+    regex_token_iterator& operator=(const regex_token_iterator&);
+
+    bool operator==(const regex_token_iterator& __x) const;
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const regex_token_iterator& __x) const {return !(*this == __x);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    const value_type& operator*() const {return *__result_;}
+    _LIBCPP_INLINE_VISIBILITY
+    const value_type* operator->() const {return __result_;}
+
+    regex_token_iterator& operator++();
+    _LIBCPP_INLINE_VISIBILITY
+    regex_token_iterator operator++(int)
+    {
+        regex_token_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+private:
+    void __init(_BidirectionalIterator __a, _BidirectionalIterator __b);
+    void __establish_result () {
+        if (__subs_[__n_] == -1)
+            __result_ = &__position_->prefix();
+        else
+            __result_ = &(*__position_)[__subs_[__n_]];
+        }
+};
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>::
+    regex_token_iterator()
+    : __result_(nullptr),
+      __suffix_(),
+      __n_(0)
+{
+}
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+void
+regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>::
+    __init(_BidirectionalIterator __a, _BidirectionalIterator __b)
+{
+    if (__position_ != _Position())
+        __establish_result ();
+    else if (__subs_[__n_] == -1)
+    {
+        __suffix_.matched = true;
+        __suffix_.first = __a;
+        __suffix_.second = __b;
+        __result_ = &__suffix_;
+    }
+    else
+        __result_ = nullptr;
+}
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>::
+    regex_token_iterator(_BidirectionalIterator __a, _BidirectionalIterator __b,
+                         const regex_type& __re, int __submatch,
+                         regex_constants::match_flag_type __m)
+    : __position_(__a, __b, __re, __m),
+      __n_(0),
+      __subs_(1, __submatch)
+{
+    __init(__a, __b);
+}
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>::
+    regex_token_iterator(_BidirectionalIterator __a, _BidirectionalIterator __b,
+                         const regex_type& __re, const vector<int>& __submatches,
+                         regex_constants::match_flag_type __m)
+    : __position_(__a, __b, __re, __m),
+      __n_(0),
+      __subs_(__submatches)
+{
+    __init(__a, __b);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>::
+    regex_token_iterator(_BidirectionalIterator __a, _BidirectionalIterator __b,
+                         const regex_type& __re,
+                         initializer_list<int> __submatches,
+                         regex_constants::match_flag_type __m)
+    : __position_(__a, __b, __re, __m),
+      __n_(0),
+      __subs_(__submatches)
+{
+    __init(__a, __b);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+template <size_t _Np>
+regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>::
+    regex_token_iterator(_BidirectionalIterator __a, _BidirectionalIterator __b,
+                             const regex_type& __re,
+                             const int (&__submatches)[_Np],
+                             regex_constants::match_flag_type __m)
+    : __position_(__a, __b, __re, __m),
+      __n_(0),
+      __subs_(begin(__submatches), end(__submatches))
+{
+    __init(__a, __b);
+}
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>::
+    regex_token_iterator(const regex_token_iterator& __x)
+    : __position_(__x.__position_),
+      __result_(__x.__result_),
+      __suffix_(__x.__suffix_),
+      __n_(__x.__n_),
+      __subs_(__x.__subs_)
+{
+    if (__x.__result_ == &__x.__suffix_)
+        __result_ = &__suffix_;
+    else if ( __result_ != nullptr )
+        __establish_result ();
+}
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>&
+regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>::
+    operator=(const regex_token_iterator& __x)
+{
+    if (this != &__x)
+    {
+        __position_ = __x.__position_;
+        if (__x.__result_ == &__x.__suffix_)
+            __result_ = &__suffix_;
+        else
+            __result_ = __x.__result_;
+        __suffix_ = __x.__suffix_;
+        __n_ = __x.__n_;
+        __subs_ = __x.__subs_;
+
+        if ( __result_ != nullptr && __result_ != &__suffix_ )
+            __establish_result();
+    }
+    return *this;
+}
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+bool
+regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>::
+    operator==(const regex_token_iterator& __x) const
+{
+    if (__result_ == nullptr && __x.__result_ == nullptr)
+        return true;
+    if (__result_ == &__suffix_ && __x.__result_ == &__x.__suffix_ &&
+            __suffix_ == __x.__suffix_)
+        return true;
+    if (__result_ == nullptr || __x.__result_ == nullptr)
+        return false;
+    if (__result_ == &__suffix_ || __x.__result_ == &__x.__suffix_)
+        return false;
+    return __position_ == __x.__position_ && __n_ == __x.__n_ &&
+           __subs_ == __x.__subs_;
+}
+
+template <class _BidirectionalIterator, class _CharT, class _Traits>
+regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>&
+regex_token_iterator<_BidirectionalIterator, _CharT, _Traits>::operator++()
+{
+    _Position __prev = __position_;
+    if (__result_ == &__suffix_)
+        __result_ = nullptr;
+    else if (static_cast<size_t>(__n_ + 1) < __subs_.size())
+    {
+        ++__n_;
+        __establish_result();
+    }
+    else
+    {
+        __n_ = 0;
+        ++__position_;
+        if (__position_ != _Position())
+            __establish_result();
+        else
+        {
+            if (_VSTD::find(__subs_.begin(), __subs_.end(), -1) != __subs_.end()
+                && __prev->suffix().length() != 0)
+            {
+                __suffix_.matched = true;
+                __suffix_.first = __prev->suffix().first;
+                __suffix_.second = __prev->suffix().second;
+                __result_ = &__suffix_;
+            }
+            else
+                __result_ = nullptr;
+        }
+    }
+    return *this;
+}
+
+// regex_replace
+
+template <class _OutputIterator, class _BidirectionalIterator,
+          class _Traits, class _CharT>
+_OutputIterator
+regex_replace(_OutputIterator __output_iter,
+              _BidirectionalIterator __first, _BidirectionalIterator __last,
+              const basic_regex<_CharT, _Traits>& __e, const _CharT* __fmt,
+              regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    typedef regex_iterator<_BidirectionalIterator, _CharT, _Traits> _Iter;
+    _Iter __i(__first, __last, __e, __flags);
+    _Iter __eof;
+    if (__i == __eof)
+    {
+        if (!(__flags & regex_constants::format_no_copy))
+            __output_iter = _VSTD::copy(__first, __last, __output_iter);
+    }
+    else
+    {
+        sub_match<_BidirectionalIterator> __lm;
+        for (size_t __len = char_traits<_CharT>::length(__fmt); __i != __eof; ++__i)
+        {
+            if (!(__flags & regex_constants::format_no_copy))
+                __output_iter = _VSTD::copy(__i->prefix().first, __i->prefix().second, __output_iter);
+            __output_iter = __i->format(__output_iter, __fmt, __fmt + __len, __flags);
+            __lm = __i->suffix();
+            if (__flags & regex_constants::format_first_only)
+                break;
+        }
+        if (!(__flags & regex_constants::format_no_copy))
+            __output_iter = _VSTD::copy(__lm.first, __lm.second, __output_iter);
+    }
+    return __output_iter;
+}
+
+template <class _OutputIterator, class _BidirectionalIterator,
+          class _Traits, class _CharT, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+_OutputIterator
+regex_replace(_OutputIterator __output_iter,
+              _BidirectionalIterator __first, _BidirectionalIterator __last,
+              const basic_regex<_CharT, _Traits>& __e,
+              const basic_string<_CharT, _ST, _SA>& __fmt,
+              regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    return _VSTD::regex_replace(__output_iter, __first, __last, __e, __fmt.c_str(), __flags);
+}
+
+template <class _Traits, class _CharT, class _ST, class _SA, class _FST,
+          class _FSA>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_string<_CharT, _ST, _SA>
+regex_replace(const basic_string<_CharT, _ST, _SA>& __s,
+              const basic_regex<_CharT, _Traits>& __e,
+              const basic_string<_CharT, _FST, _FSA>& __fmt,
+              regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    basic_string<_CharT, _ST, _SA> __r;
+    _VSTD::regex_replace(back_inserter(__r), __s.begin(), __s.end(), __e,
+                        __fmt.c_str(), __flags);
+    return __r;
+}
+
+template <class _Traits, class _CharT, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_string<_CharT, _ST, _SA>
+regex_replace(const basic_string<_CharT, _ST, _SA>& __s,
+              const basic_regex<_CharT, _Traits>& __e, const _CharT* __fmt,
+              regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    basic_string<_CharT, _ST, _SA> __r;
+    _VSTD::regex_replace(back_inserter(__r), __s.begin(), __s.end(), __e,
+                        __fmt, __flags);
+    return __r;
+}
+
+template <class _Traits, class _CharT, class _ST, class _SA>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_string<_CharT>
+regex_replace(const _CharT* __s,
+              const basic_regex<_CharT, _Traits>& __e,
+              const basic_string<_CharT, _ST, _SA>& __fmt,
+              regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    basic_string<_CharT> __r;
+    _VSTD::regex_replace(back_inserter(__r), __s,
+                        __s + char_traits<_CharT>::length(__s), __e,
+                        __fmt.c_str(), __flags);
+    return __r;
+}
+
+template <class _Traits, class _CharT>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_string<_CharT>
+regex_replace(const _CharT* __s,
+              const basic_regex<_CharT, _Traits>& __e,
+              const _CharT* __fmt,
+              regex_constants::match_flag_type __flags = regex_constants::match_default)
+{
+    basic_string<_CharT> __r;
+    _VSTD::regex_replace(back_inserter(__r), __s,
+                        __s + char_traits<_CharT>::length(__s), __e,
+                        __fmt, __flags);
+    return __r;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_REGEX
diff --git a/contrib/libs/cxxsupp/libcxx/include/scoped_allocator b/contrib/libs/cxxsupp/libcxx/include/scoped_allocator
new file mode 100644
index 00000000000..dc24d30b510
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/scoped_allocator
@@ -0,0 +1,684 @@
+// -*- C++ -*-
+//===-------------------------- scoped_allocator --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SCOPED_ALLOCATOR
+#define _LIBCPP_SCOPED_ALLOCATOR
+
+/*
+    scoped_allocator synopsis
+
+namespace std
+{
+
+template <class OuterAlloc, class... InnerAllocs>
+class scoped_allocator_adaptor : public OuterAlloc
+{
+    typedef allocator_traits<OuterAlloc> OuterTraits; // exposition only
+    scoped_allocator_adaptor<InnerAllocs...> inner;   // exposition only
+public:
+
+    typedef OuterAlloc outer_allocator_type;
+    typedef see below inner_allocator_type;
+
+    typedef typename OuterTraits::value_type value_type;
+    typedef typename OuterTraits::size_type size_type;
+    typedef typename OuterTraits::difference_type difference_type;
+    typedef typename OuterTraits::pointer pointer;
+    typedef typename OuterTraits::const_pointer const_pointer;
+    typedef typename OuterTraits::void_pointer void_pointer;
+    typedef typename OuterTraits::const_void_pointer const_void_pointer;
+
+    typedef see below propagate_on_container_copy_assignment;
+    typedef see below propagate_on_container_move_assignment;
+    typedef see below propagate_on_container_swap;
+    typedef see below is_always_equal;
+
+    template <class Tp>
+        struct rebind
+        {
+            typedef scoped_allocator_adaptor<
+                OuterTraits::template rebind_alloc<Tp>, InnerAllocs...> other;
+        };
+
+    scoped_allocator_adaptor();
+    template <class OuterA2>
+        scoped_allocator_adaptor(OuterA2&& outerAlloc,
+                                 const InnerAllocs&... innerAllocs) noexcept;
+    scoped_allocator_adaptor(const scoped_allocator_adaptor& other) noexcept;
+    scoped_allocator_adaptor(scoped_allocator_adaptor&& other) noexcept;
+    template <class OuterA2>
+        scoped_allocator_adaptor(const scoped_allocator_adaptor<OuterA2, InnerAllocs...>& other) noexcept;
+    template <class OuterA2>
+        scoped_allocator_adaptor(const scoped_allocator_adaptor<OuterA2, InnerAllocs...>&& other) noexcept;
+
+    scoped_allocator_adaptor& operator=(const scoped_allocator_adaptor&) = default;
+    scoped_allocator_adaptor& operator=(scoped_allocator_adaptor&&) = default;
+    ~scoped_allocator_adaptor();
+
+    inner_allocator_type& inner_allocator() noexcept;
+    const inner_allocator_type& inner_allocator() const noexcept;
+
+    outer_allocator_type& outer_allocator() noexcept;
+    const outer_allocator_type& outer_allocator() const noexcept;
+
+    pointer allocate(size_type n);                           // [[nodiscard]] in C++20
+    pointer allocate(size_type n, const_void_pointer hint);  // [[nodiscard]] in C++20
+    void deallocate(pointer p, size_type n) noexcept;
+
+    size_type max_size() const;
+    template <class T, class... Args> void construct(T* p, Args&& args);
+    template <class T1, class T2, class... Args1, class... Args2>
+        void construct(pair<T1, T2>* p, piecewise_construct t, tuple<Args1...> x,
+                       tuple<Args2...> y);
+    template <class T1, class T2>
+        void construct(pair<T1, T2>* p);
+    template <class T1, class T2, class U, class V>
+        void construct(pair<T1, T2>* p, U&& x, V&& y);
+    template <class T1, class T2, class U, class V>
+        void construct(pair<T1, T2>* p, const pair<U, V>& x);
+    template <class T1, class T2, class U, class V>
+        void construct(pair<T1, T2>* p, pair<U, V>&& x);
+    template <class T> void destroy(T* p);
+
+    template <class T> void destroy(T* p) noexcept;
+
+    scoped_allocator_adaptor select_on_container_copy_construction() const noexcept;
+};
+
+template <class OuterA1, class OuterA2, class... InnerAllocs>
+    bool
+    operator==(const scoped_allocator_adaptor<OuterA1, InnerAllocs...>& a,
+               const scoped_allocator_adaptor<OuterA2, InnerAllocs...>& b) noexcept;
+
+template <class OuterA1, class OuterA2, class... InnerAllocs>
+    bool
+    operator!=(const scoped_allocator_adaptor<OuterA1, InnerAllocs...>& a,
+               const scoped_allocator_adaptor<OuterA2, InnerAllocs...>& b) noexcept;
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__utility/forward.h>
+#include <memory>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_CXX03_LANG)
+
+// scoped_allocator_adaptor
+
+template <class ..._Allocs>
+class scoped_allocator_adaptor;
+
+template <class ..._Allocs> struct __get_poc_copy_assignment;
+
+template <class _A0>
+struct __get_poc_copy_assignment<_A0>
+{
+    static const bool value = allocator_traits<_A0>::
+                              propagate_on_container_copy_assignment::value;
+};
+
+template <class _A0, class ..._Allocs>
+struct __get_poc_copy_assignment<_A0, _Allocs...>
+{
+    static const bool value =
+        allocator_traits<_A0>::propagate_on_container_copy_assignment::value ||
+        __get_poc_copy_assignment<_Allocs...>::value;
+};
+
+template <class ..._Allocs> struct __get_poc_move_assignment;
+
+template <class _A0>
+struct __get_poc_move_assignment<_A0>
+{
+    static const bool value = allocator_traits<_A0>::
+                              propagate_on_container_move_assignment::value;
+};
+
+template <class _A0, class ..._Allocs>
+struct __get_poc_move_assignment<_A0, _Allocs...>
+{
+    static const bool value =
+        allocator_traits<_A0>::propagate_on_container_move_assignment::value ||
+        __get_poc_move_assignment<_Allocs...>::value;
+};
+
+template <class ..._Allocs> struct __get_poc_swap;
+
+template <class _A0>
+struct __get_poc_swap<_A0>
+{
+    static const bool value = allocator_traits<_A0>::
+                              propagate_on_container_swap::value;
+};
+
+template <class _A0, class ..._Allocs>
+struct __get_poc_swap<_A0, _Allocs...>
+{
+    static const bool value =
+        allocator_traits<_A0>::propagate_on_container_swap::value ||
+        __get_poc_swap<_Allocs...>::value;
+};
+
+template <class ..._Allocs> struct __get_is_always_equal;
+
+template <class _A0>
+struct __get_is_always_equal<_A0>
+{
+    static const bool value = allocator_traits<_A0>::is_always_equal::value;
+};
+
+template <class _A0, class ..._Allocs>
+struct __get_is_always_equal<_A0, _Allocs...>
+{
+    static const bool value =
+        allocator_traits<_A0>::is_always_equal::value &&
+        __get_is_always_equal<_Allocs...>::value;
+};
+
+template <class ..._Allocs>
+class __scoped_allocator_storage;
+
+template <class _OuterAlloc, class... _InnerAllocs>
+class __scoped_allocator_storage<_OuterAlloc, _InnerAllocs...>
+    : public _OuterAlloc
+{
+    typedef _OuterAlloc outer_allocator_type;
+protected:
+    typedef scoped_allocator_adaptor<_InnerAllocs...> inner_allocator_type;
+
+private:
+    inner_allocator_type __inner_;
+
+protected:
+
+    _LIBCPP_INLINE_VISIBILITY
+    __scoped_allocator_storage() _NOEXCEPT {}
+
+    template <class _OuterA2,
+              class = typename enable_if<
+                        is_constructible<outer_allocator_type, _OuterA2>::value
+                      >::type>
+        _LIBCPP_INLINE_VISIBILITY
+        __scoped_allocator_storage(_OuterA2&& __outerAlloc,
+                                   const _InnerAllocs& ...__innerAllocs) _NOEXCEPT
+            : outer_allocator_type(_VSTD::forward<_OuterA2>(__outerAlloc)),
+              __inner_(__innerAllocs...) {}
+
+    template <class _OuterA2,
+              class = typename enable_if<
+                        is_constructible<outer_allocator_type, const _OuterA2&>::value
+                      >::type>
+        _LIBCPP_INLINE_VISIBILITY
+        __scoped_allocator_storage(
+            const __scoped_allocator_storage<_OuterA2, _InnerAllocs...>& __other) _NOEXCEPT
+            : outer_allocator_type(__other.outer_allocator()),
+              __inner_(__other.inner_allocator()) {}
+
+    template <class _OuterA2,
+              class = typename enable_if<
+                        is_constructible<outer_allocator_type, _OuterA2>::value
+                      >::type>
+        _LIBCPP_INLINE_VISIBILITY
+        __scoped_allocator_storage(
+            __scoped_allocator_storage<_OuterA2, _InnerAllocs...>&& __other) _NOEXCEPT
+            : outer_allocator_type(_VSTD::move(__other.outer_allocator())),
+              __inner_(_VSTD::move(__other.inner_allocator())) {}
+
+    template <class _OuterA2,
+              class = typename enable_if<
+                        is_constructible<outer_allocator_type, _OuterA2>::value
+                      >::type>
+        _LIBCPP_INLINE_VISIBILITY
+        __scoped_allocator_storage(_OuterA2&& __o,
+                                   const inner_allocator_type& __i) _NOEXCEPT
+            : outer_allocator_type(_VSTD::forward<_OuterA2>(__o)),
+              __inner_(__i)
+        {
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    inner_allocator_type& inner_allocator() _NOEXCEPT             {return __inner_;}
+    _LIBCPP_INLINE_VISIBILITY
+    const inner_allocator_type& inner_allocator() const _NOEXCEPT {return __inner_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    outer_allocator_type& outer_allocator() _NOEXCEPT
+        {return static_cast<outer_allocator_type&>(*this);}
+    _LIBCPP_INLINE_VISIBILITY
+    const outer_allocator_type& outer_allocator() const _NOEXCEPT
+        {return static_cast<const outer_allocator_type&>(*this);}
+
+    scoped_allocator_adaptor<outer_allocator_type, _InnerAllocs...>
+    _LIBCPP_INLINE_VISIBILITY
+    select_on_container_copy_construction() const _NOEXCEPT
+        {
+            return scoped_allocator_adaptor<outer_allocator_type, _InnerAllocs...>
+            (
+                allocator_traits<outer_allocator_type>::
+                    select_on_container_copy_construction(outer_allocator()),
+                allocator_traits<inner_allocator_type>::
+                    select_on_container_copy_construction(inner_allocator())
+            );
+        }
+
+    template <class...> friend class __scoped_allocator_storage;
+};
+
+template <class _OuterAlloc>
+class __scoped_allocator_storage<_OuterAlloc>
+    : public _OuterAlloc
+{
+    typedef _OuterAlloc outer_allocator_type;
+protected:
+    typedef scoped_allocator_adaptor<_OuterAlloc> inner_allocator_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __scoped_allocator_storage() _NOEXCEPT {}
+
+    template <class _OuterA2,
+              class = typename enable_if<
+                        is_constructible<outer_allocator_type, _OuterA2>::value
+                      >::type>
+        _LIBCPP_INLINE_VISIBILITY
+        __scoped_allocator_storage(_OuterA2&& __outerAlloc) _NOEXCEPT
+            : outer_allocator_type(_VSTD::forward<_OuterA2>(__outerAlloc)) {}
+
+    template <class _OuterA2,
+              class = typename enable_if<
+                        is_constructible<outer_allocator_type, const _OuterA2&>::value
+                      >::type>
+        _LIBCPP_INLINE_VISIBILITY
+        __scoped_allocator_storage(
+            const __scoped_allocator_storage<_OuterA2>& __other) _NOEXCEPT
+            : outer_allocator_type(__other.outer_allocator()) {}
+
+    template <class _OuterA2,
+              class = typename enable_if<
+                        is_constructible<outer_allocator_type, _OuterA2>::value
+                      >::type>
+        _LIBCPP_INLINE_VISIBILITY
+        __scoped_allocator_storage(
+            __scoped_allocator_storage<_OuterA2>&& __other) _NOEXCEPT
+            : outer_allocator_type(_VSTD::move(__other.outer_allocator())) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    inner_allocator_type& inner_allocator() _NOEXCEPT
+        {return static_cast<inner_allocator_type&>(*this);}
+    _LIBCPP_INLINE_VISIBILITY
+    const inner_allocator_type& inner_allocator() const _NOEXCEPT
+        {return static_cast<const inner_allocator_type&>(*this);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    outer_allocator_type& outer_allocator() _NOEXCEPT
+        {return static_cast<outer_allocator_type&>(*this);}
+    _LIBCPP_INLINE_VISIBILITY
+    const outer_allocator_type& outer_allocator() const _NOEXCEPT
+        {return static_cast<const outer_allocator_type&>(*this);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    scoped_allocator_adaptor<outer_allocator_type>
+    select_on_container_copy_construction() const _NOEXCEPT
+        {return scoped_allocator_adaptor<outer_allocator_type>(
+            allocator_traits<outer_allocator_type>::
+                select_on_container_copy_construction(outer_allocator())
+        );}
+
+    __scoped_allocator_storage(const outer_allocator_type& __o,
+                               const inner_allocator_type& __i) _NOEXCEPT;
+
+    template <class...> friend class __scoped_allocator_storage;
+};
+
+// __outermost
+
+template <class _Alloc>
+decltype(declval<_Alloc>().outer_allocator(), true_type())
+__has_outer_allocator_test(_Alloc&& __a);
+
+template <class _Alloc>
+false_type
+__has_outer_allocator_test(const volatile _Alloc& __a);
+
+template <class _Alloc>
+struct __has_outer_allocator
+    : public common_type
+             <
+                 decltype(__has_outer_allocator_test(declval<_Alloc&>()))
+             >::type
+{
+};
+
+template <class _Alloc, bool = __has_outer_allocator<_Alloc>::value>
+struct __outermost
+{
+    typedef _Alloc type;
+    _LIBCPP_INLINE_VISIBILITY
+    type& operator()(type& __a) const _NOEXCEPT {return __a;}
+};
+
+template <class _Alloc>
+struct __outermost<_Alloc, true>
+{
+    typedef typename remove_reference
+                     <
+                        decltype(declval<_Alloc>().outer_allocator())
+                     >::type                                    _OuterAlloc;
+    typedef typename __outermost<_OuterAlloc>::type             type;
+    _LIBCPP_INLINE_VISIBILITY
+    type& operator()(_Alloc& __a) const _NOEXCEPT
+        {return __outermost<_OuterAlloc>()(__a.outer_allocator());}
+};
+
+template <class _OuterAlloc, class... _InnerAllocs>
+class _LIBCPP_TEMPLATE_VIS scoped_allocator_adaptor<_OuterAlloc, _InnerAllocs...>
+    : public __scoped_allocator_storage<_OuterAlloc, _InnerAllocs...>
+{
+    typedef __scoped_allocator_storage<_OuterAlloc, _InnerAllocs...> base;
+    typedef allocator_traits<_OuterAlloc>             _OuterTraits;
+public:
+    typedef _OuterAlloc                               outer_allocator_type;
+    typedef typename base::inner_allocator_type       inner_allocator_type;
+    typedef typename _OuterTraits::size_type          size_type;
+    typedef typename _OuterTraits::difference_type    difference_type;
+    typedef typename _OuterTraits::pointer            pointer;
+    typedef typename _OuterTraits::const_pointer      const_pointer;
+    typedef typename _OuterTraits::void_pointer       void_pointer;
+    typedef typename _OuterTraits::const_void_pointer const_void_pointer;
+
+    typedef integral_constant
+            <
+                bool,
+                __get_poc_copy_assignment<outer_allocator_type,
+                                          _InnerAllocs...>::value
+            > propagate_on_container_copy_assignment;
+    typedef integral_constant
+            <
+                bool,
+                __get_poc_move_assignment<outer_allocator_type,
+                                          _InnerAllocs...>::value
+            > propagate_on_container_move_assignment;
+    typedef integral_constant
+            <
+                bool,
+                __get_poc_swap<outer_allocator_type, _InnerAllocs...>::value
+            > propagate_on_container_swap;
+    typedef integral_constant
+            <
+                bool,
+                __get_is_always_equal<outer_allocator_type, _InnerAllocs...>::value
+            > is_always_equal;
+
+    template <class _Tp>
+    struct rebind
+    {
+        typedef scoped_allocator_adaptor
+        <
+            typename _OuterTraits::template rebind_alloc<_Tp>, _InnerAllocs...
+        > other;
+    };
+
+    _LIBCPP_INLINE_VISIBILITY
+    scoped_allocator_adaptor() _NOEXCEPT {}
+    template <class _OuterA2,
+              class = typename enable_if<
+                        is_constructible<outer_allocator_type, _OuterA2>::value
+                      >::type>
+        _LIBCPP_INLINE_VISIBILITY
+        scoped_allocator_adaptor(_OuterA2&& __outerAlloc,
+                                 const _InnerAllocs& ...__innerAllocs) _NOEXCEPT
+            : base(_VSTD::forward<_OuterA2>(__outerAlloc), __innerAllocs...) {}
+    // scoped_allocator_adaptor(const scoped_allocator_adaptor& __other) = default;
+    template <class _OuterA2,
+              class = typename enable_if<
+                        is_constructible<outer_allocator_type, const _OuterA2&>::value
+                      >::type>
+        _LIBCPP_INLINE_VISIBILITY
+        scoped_allocator_adaptor(
+            const scoped_allocator_adaptor<_OuterA2, _InnerAllocs...>& __other) _NOEXCEPT
+                : base(__other) {}
+    template <class _OuterA2,
+              class = typename enable_if<
+                        is_constructible<outer_allocator_type, _OuterA2>::value
+                      >::type>
+        _LIBCPP_INLINE_VISIBILITY
+        scoped_allocator_adaptor(
+            scoped_allocator_adaptor<_OuterA2, _InnerAllocs...>&& __other) _NOEXCEPT
+                : base(_VSTD::move(__other)) {}
+
+    // scoped_allocator_adaptor& operator=(const scoped_allocator_adaptor&) = default;
+    // scoped_allocator_adaptor& operator=(scoped_allocator_adaptor&&) = default;
+    // ~scoped_allocator_adaptor() = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    inner_allocator_type& inner_allocator() _NOEXCEPT
+        {return base::inner_allocator();}
+    _LIBCPP_INLINE_VISIBILITY
+    const inner_allocator_type& inner_allocator() const _NOEXCEPT
+        {return base::inner_allocator();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    outer_allocator_type& outer_allocator() _NOEXCEPT
+        {return base::outer_allocator();}
+    _LIBCPP_INLINE_VISIBILITY
+    const outer_allocator_type& outer_allocator() const _NOEXCEPT
+        {return base::outer_allocator();}
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    pointer allocate(size_type __n)
+        {return allocator_traits<outer_allocator_type>::
+            allocate(outer_allocator(), __n);}
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    pointer allocate(size_type __n, const_void_pointer __hint)
+        {return allocator_traits<outer_allocator_type>::
+            allocate(outer_allocator(), __n, __hint);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void deallocate(pointer __p, size_type __n) _NOEXCEPT
+        {allocator_traits<outer_allocator_type>::
+            deallocate(outer_allocator(), __p, __n);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const
+        {return allocator_traits<outer_allocator_type>::max_size(outer_allocator());}
+
+    template <class _Tp, class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        void construct(_Tp* __p, _Args&& ...__args)
+            {__construct(__uses_alloc_ctor<_Tp, inner_allocator_type&, _Args...>(),
+                         __p, _VSTD::forward<_Args>(__args)...);}
+
+    template <class _T1, class _T2, class... _Args1, class... _Args2>
+    void construct(pair<_T1, _T2>* __p, piecewise_construct_t,
+                       tuple<_Args1...> __x, tuple<_Args2...> __y)
+    {
+        typedef __outermost<outer_allocator_type> _OM;
+        allocator_traits<typename _OM::type>::construct(
+            _OM()(outer_allocator()), __p, piecewise_construct
+          , __transform_tuple(
+              typename __uses_alloc_ctor<
+                  _T1, inner_allocator_type&, _Args1...
+              >::type()
+            , _VSTD::move(__x)
+            , typename __make_tuple_indices<sizeof...(_Args1)>::type{}
+          )
+          , __transform_tuple(
+              typename __uses_alloc_ctor<
+                  _T2, inner_allocator_type&, _Args2...
+              >::type()
+            , _VSTD::move(__y)
+            , typename __make_tuple_indices<sizeof...(_Args2)>::type{}
+          )
+        );
+    }
+
+    template <class _T1, class _T2>
+    void construct(pair<_T1, _T2>* __p)
+    { construct(__p, piecewise_construct, tuple<>{}, tuple<>{}); }
+
+    template <class _T1, class _T2, class _Up, class _Vp>
+    void construct(pair<_T1, _T2>* __p, _Up&& __x, _Vp&& __y) {
+        construct(__p, piecewise_construct,
+                  _VSTD::forward_as_tuple(_VSTD::forward<_Up>(__x)),
+                  _VSTD::forward_as_tuple(_VSTD::forward<_Vp>(__y)));
+    }
+
+    template <class _T1, class _T2, class _Up, class _Vp>
+    void construct(pair<_T1, _T2>* __p, const pair<_Up, _Vp>& __x) {
+        construct(__p, piecewise_construct,
+                  _VSTD::forward_as_tuple(__x.first),
+                  _VSTD::forward_as_tuple(__x.second));
+    }
+
+    template <class _T1, class _T2, class _Up, class _Vp>
+    void construct(pair<_T1, _T2>* __p, pair<_Up, _Vp>&& __x) {
+        construct(__p, piecewise_construct,
+                  _VSTD::forward_as_tuple(_VSTD::forward<_Up>(__x.first)),
+                  _VSTD::forward_as_tuple(_VSTD::forward<_Vp>(__x.second)));
+    }
+
+    template <class _Tp>
+        _LIBCPP_INLINE_VISIBILITY
+        void destroy(_Tp* __p)
+            {
+                typedef __outermost<outer_allocator_type> _OM;
+                allocator_traits<typename _OM::type>::
+                                         destroy(_OM()(outer_allocator()), __p);
+            }
+
+    _LIBCPP_INLINE_VISIBILITY
+    scoped_allocator_adaptor select_on_container_copy_construction() const _NOEXCEPT
+        {return base::select_on_container_copy_construction();}
+
+private:
+
+
+    template <class _OuterA2,
+              class = typename enable_if<
+                        is_constructible<outer_allocator_type, _OuterA2>::value
+                      >::type>
+    _LIBCPP_INLINE_VISIBILITY
+    scoped_allocator_adaptor(_OuterA2&& __o,
+                             const inner_allocator_type& __i) _NOEXCEPT
+        : base(_VSTD::forward<_OuterA2>(__o), __i) {}
+
+    template <class _Tp, class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        void __construct(integral_constant<int, 0>, _Tp* __p, _Args&& ...__args)
+            {
+                typedef __outermost<outer_allocator_type> _OM;
+                allocator_traits<typename _OM::type>::construct
+                (
+                    _OM()(outer_allocator()),
+                    __p,
+                    _VSTD::forward<_Args>(__args)...
+                );
+            }
+
+    template <class _Tp, class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        void __construct(integral_constant<int, 1>, _Tp* __p, _Args&& ...__args)
+            {
+                typedef __outermost<outer_allocator_type> _OM;
+                allocator_traits<typename _OM::type>::construct
+                (
+                    _OM()(outer_allocator()),
+                    __p, allocator_arg, inner_allocator(),
+                    _VSTD::forward<_Args>(__args)...
+                );
+            }
+
+    template <class _Tp, class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        void __construct(integral_constant<int, 2>, _Tp* __p, _Args&& ...__args)
+            {
+                typedef __outermost<outer_allocator_type> _OM;
+                allocator_traits<typename _OM::type>::construct
+                (
+                    _OM()(outer_allocator()),
+                    __p,
+                    _VSTD::forward<_Args>(__args)...,
+                    inner_allocator()
+                );
+            }
+
+    template <class ..._Args, size_t ..._Idx>
+    _LIBCPP_INLINE_VISIBILITY
+    tuple<_Args&&...>
+    __transform_tuple(integral_constant<int, 0>, tuple<_Args...>&& __t,
+                      __tuple_indices<_Idx...>)
+    {
+        return _VSTD::forward_as_tuple(_VSTD::get<_Idx>(_VSTD::move(__t))...);
+    }
+
+    template <class ..._Args, size_t ..._Idx>
+    _LIBCPP_INLINE_VISIBILITY
+    tuple<allocator_arg_t, inner_allocator_type&, _Args&&...>
+    __transform_tuple(integral_constant<int, 1>, tuple<_Args...> && __t,
+                      __tuple_indices<_Idx...>)
+    {
+        using _Tup = tuple<allocator_arg_t, inner_allocator_type&, _Args&&...>;
+        return _Tup(allocator_arg, inner_allocator(),
+                    _VSTD::get<_Idx>(_VSTD::move(__t))...);
+    }
+
+    template <class ..._Args, size_t ..._Idx>
+    _LIBCPP_INLINE_VISIBILITY
+    tuple<_Args&&..., inner_allocator_type&>
+    __transform_tuple(integral_constant<int, 2>, tuple<_Args...> && __t,
+                      __tuple_indices<_Idx...>)
+    {
+        using _Tup = tuple<_Args&&..., inner_allocator_type&>;
+        return _Tup(_VSTD::get<_Idx>(_VSTD::move(__t))..., inner_allocator());
+    }
+
+    template <class...> friend class __scoped_allocator_storage;
+};
+
+template <class _OuterA1, class _OuterA2>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const scoped_allocator_adaptor<_OuterA1>& __a,
+           const scoped_allocator_adaptor<_OuterA2>& __b) _NOEXCEPT
+{
+    return __a.outer_allocator() == __b.outer_allocator();
+}
+
+template <class _OuterA1, class _OuterA2, class _InnerA0, class... _InnerAllocs>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const scoped_allocator_adaptor<_OuterA1, _InnerA0, _InnerAllocs...>& __a,
+           const scoped_allocator_adaptor<_OuterA2, _InnerA0, _InnerAllocs...>& __b) _NOEXCEPT
+{
+    return __a.outer_allocator() == __b.outer_allocator() &&
+           __a.inner_allocator() == __b.inner_allocator();
+}
+
+template <class _OuterA1, class _OuterA2, class... _InnerAllocs>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const scoped_allocator_adaptor<_OuterA1, _InnerAllocs...>& __a,
+           const scoped_allocator_adaptor<_OuterA2, _InnerAllocs...>& __b) _NOEXCEPT
+{
+    return !(__a == __b);
+}
+
+#endif // !defined(_LIBCPP_CXX03_LANG)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_SCOPED_ALLOCATOR
diff --git a/contrib/libs/cxxsupp/libcxx/include/semaphore b/contrib/libs/cxxsupp/libcxx/include/semaphore
new file mode 100644
index 00000000000..4f9ecd0461b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/semaphore
@@ -0,0 +1,240 @@
+// -*- C++ -*-
+//===--------------------------- semaphore --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SEMAPHORE
+#define _LIBCPP_SEMAPHORE
+
+/*
+    semaphore synopsis
+
+namespace std {
+
+template<ptrdiff_t least_max_value = implementation-defined>
+class counting_semaphore
+{
+public:
+static constexpr ptrdiff_t max() noexcept;
+
+constexpr explicit counting_semaphore(ptrdiff_t desired);
+~counting_semaphore();
+
+counting_semaphore(const counting_semaphore&) = delete;
+counting_semaphore& operator=(const counting_semaphore&) = delete;
+
+void release(ptrdiff_t update = 1);
+void acquire();
+bool try_acquire() noexcept;
+template<class Rep, class Period>
+    bool try_acquire_for(const chrono::duration<Rep, Period>& rel_time);
+template<class Clock, class Duration>
+    bool try_acquire_until(const chrono::time_point<Clock, Duration>& abs_time);
+
+private:
+ptrdiff_t counter; // exposition only
+};
+
+using binary_semaphore = counting_semaphore<1>;
+
+}
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <__threading_support>
+#include <atomic>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_HAS_NO_THREADS
+# error <semaphore> is not supported on this single threaded system
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#if _LIBCPP_STD_VER >= 14
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+/*
+
+__atomic_semaphore_base is the general-case implementation, to be used for
+user-requested least-max values that exceed the OS implementation support
+(incl. when the OS has no support of its own) and for binary semaphores.
+
+It is a typical Dijkstra semaphore algorithm over atomics, wait and notify
+functions. It avoids contention against users' own use of those facilities.
+
+*/
+
+class __atomic_semaphore_base
+{
+    __atomic_base<ptrdiff_t> __a;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit __atomic_semaphore_base(ptrdiff_t __count) : __a(__count)
+    {
+    }
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void release(ptrdiff_t __update = 1)
+    {
+        if(0 < __a.fetch_add(__update, memory_order_release))
+            ;
+        else if(__update > 1)
+            __a.notify_all();
+        else
+            __a.notify_one();
+    }
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void acquire()
+    {
+        auto const __test_fn = [this]() -> bool {
+            auto __old = __a.load(memory_order_relaxed);
+            return (__old != 0) && __a.compare_exchange_strong(__old, __old - 1, memory_order_acquire, memory_order_relaxed);
+        };
+        __cxx_atomic_wait(&__a.__a_, __test_fn);
+    }
+    template <class Rep, class Period>
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    bool try_acquire_for(chrono::duration<Rep, Period> const& __rel_time)
+    {
+        auto const __test_fn = [this]() -> bool {
+            auto __old = __a.load(memory_order_acquire);
+            while(1) {
+                if (__old == 0)
+                    return false;
+                if(__a.compare_exchange_strong(__old, __old - 1, memory_order_acquire, memory_order_relaxed))
+                    return true;
+            }
+        };
+        return __libcpp_thread_poll_with_backoff(__test_fn, __libcpp_timed_backoff_policy(), __rel_time);
+    }
+};
+
+#ifndef _LIBCPP_NO_NATIVE_SEMAPHORES
+
+/*
+
+__platform_semaphore_base a simple wrapper for the OS semaphore type. That
+is, every call is routed to the OS in the most direct manner possible.
+
+*/
+
+class __platform_semaphore_base
+{
+    __libcpp_semaphore_t __semaphore;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __platform_semaphore_base(ptrdiff_t __count) :
+        __semaphore()
+    {
+        __libcpp_semaphore_init(&__semaphore, __count);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    ~__platform_semaphore_base() {
+        __libcpp_semaphore_destroy(&__semaphore);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    void release(ptrdiff_t __update)
+    {
+        for(; __update; --__update)
+            __libcpp_semaphore_post(&__semaphore);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    void acquire()
+    {
+        __libcpp_semaphore_wait(&__semaphore);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    bool try_acquire_for(chrono::nanoseconds __rel_time)
+    {
+        return __libcpp_semaphore_wait_timed(&__semaphore, __rel_time);
+    }
+};
+
+template<ptrdiff_t __least_max_value>
+using __semaphore_base =
+    typename conditional<(__least_max_value > 1 && __least_max_value <= _LIBCPP_SEMAPHORE_MAX),
+                         __platform_semaphore_base,
+                         __atomic_semaphore_base>::type;
+
+#else
+
+template<ptrdiff_t __least_max_value>
+using __semaphore_base =
+    __atomic_semaphore_base;
+
+#define _LIBCPP_SEMAPHORE_MAX (numeric_limits<ptrdiff_t>::max())
+
+#endif //_LIBCPP_NO_NATIVE_SEMAPHORES
+
+template<ptrdiff_t __least_max_value = _LIBCPP_SEMAPHORE_MAX>
+class counting_semaphore
+{
+    __semaphore_base<__least_max_value> __semaphore;
+
+public:
+    static constexpr ptrdiff_t max() noexcept {
+        return __least_max_value;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit counting_semaphore(ptrdiff_t __count) : __semaphore(__count) { }
+    ~counting_semaphore() = default;
+
+    counting_semaphore(const counting_semaphore&) = delete;
+    counting_semaphore& operator=(const counting_semaphore&) = delete;
+
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void release(ptrdiff_t __update = 1)
+    {
+        __semaphore.release(__update);
+    }
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    void acquire()
+    {
+        __semaphore.acquire();
+    }
+    template<class Rep, class Period>
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    bool try_acquire_for(chrono::duration<Rep, Period> const& __rel_time)
+    {
+        return __semaphore.try_acquire_for(chrono::duration_cast<chrono::nanoseconds>(__rel_time));
+    }
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    bool try_acquire()
+    {
+        return try_acquire_for(chrono::nanoseconds::zero());
+    }
+    template <class Clock, class Duration>
+    _LIBCPP_AVAILABILITY_SYNC _LIBCPP_INLINE_VISIBILITY
+    bool try_acquire_until(chrono::time_point<Clock, Duration> const& __abs_time)
+    {
+        auto const current = Clock::now();
+        if(current >= __abs_time)
+            return try_acquire();
+        else
+            return try_acquire_for(__abs_time - current);
+    }
+};
+
+using binary_semaphore = counting_semaphore<1>;
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 14
+
+_LIBCPP_POP_MACROS
+
+#endif //_LIBCPP_SEMAPHORE
diff --git a/contrib/libs/cxxsupp/libcxx/include/set b/contrib/libs/cxxsupp/libcxx/include/set
new file mode 100644
index 00000000000..46b515ba533
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/set
@@ -0,0 +1,1521 @@
+// -*- C++ -*-
+//===---------------------------- set -------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SET
+#define _LIBCPP_SET
+
+/*
+
+    set synopsis
+
+namespace std
+{
+
+template <class Key, class Compare = less<Key>,
+          class Allocator = allocator<Key>>
+class set
+{
+public:
+    // types:
+    typedef Key                                      key_type;
+    typedef key_type                                 value_type;
+    typedef Compare                                  key_compare;
+    typedef key_compare                              value_compare;
+    typedef Allocator                                allocator_type;
+    typedef typename allocator_type::reference       reference;
+    typedef typename allocator_type::const_reference const_reference;
+    typedef typename allocator_type::size_type       size_type;
+    typedef typename allocator_type::difference_type difference_type;
+    typedef typename allocator_type::pointer         pointer;
+    typedef typename allocator_type::const_pointer   const_pointer;
+
+    typedef implementation-defined                   iterator;
+    typedef implementation-defined                   const_iterator;
+    typedef std::reverse_iterator<iterator>          reverse_iterator;
+    typedef std::reverse_iterator<const_iterator>    const_reverse_iterator;
+    typedef unspecified                              node_type;               // C++17
+    typedef INSERT_RETURN_TYPE<iterator, node_type>  insert_return_type;      // C++17
+
+    // construct/copy/destroy:
+    set()
+        noexcept(
+            is_nothrow_default_constructible<allocator_type>::value &&
+            is_nothrow_default_constructible<key_compare>::value &&
+            is_nothrow_copy_constructible<key_compare>::value);
+    explicit set(const value_compare& comp);
+    set(const value_compare& comp, const allocator_type& a);
+    template <class InputIterator>
+        set(InputIterator first, InputIterator last,
+            const value_compare& comp = value_compare());
+    template <class InputIterator>
+        set(InputIterator first, InputIterator last, const value_compare& comp,
+            const allocator_type& a);
+    set(const set& s);
+    set(set&& s)
+        noexcept(
+            is_nothrow_move_constructible<allocator_type>::value &&
+            is_nothrow_move_constructible<key_compare>::value);
+    explicit set(const allocator_type& a);
+    set(const set& s, const allocator_type& a);
+    set(set&& s, const allocator_type& a);
+    set(initializer_list<value_type> il, const value_compare& comp = value_compare());
+    set(initializer_list<value_type> il, const value_compare& comp,
+        const allocator_type& a);
+    template <class InputIterator>
+        set(InputIterator first, InputIterator last, const allocator_type& a)
+            : set(first, last, Compare(), a) {}  // C++14
+    set(initializer_list<value_type> il, const allocator_type& a)
+        : set(il, Compare(), a) {}  // C++14
+    ~set();
+
+    set& operator=(const set& s);
+    set& operator=(set&& s)
+        noexcept(
+            allocator_type::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<allocator_type>::value &&
+            is_nothrow_move_assignable<key_compare>::value);
+    set& operator=(initializer_list<value_type> il);
+
+    // iterators:
+          iterator begin() noexcept;
+    const_iterator begin() const noexcept;
+          iterator end() noexcept;
+    const_iterator end()   const noexcept;
+
+          reverse_iterator rbegin() noexcept;
+    const_reverse_iterator rbegin() const noexcept;
+          reverse_iterator rend() noexcept;
+    const_reverse_iterator rend()   const noexcept;
+
+    const_iterator         cbegin()  const noexcept;
+    const_iterator         cend()    const noexcept;
+    const_reverse_iterator crbegin() const noexcept;
+    const_reverse_iterator crend()   const noexcept;
+
+    // capacity:
+    bool      empty()    const noexcept;
+    size_type size()     const noexcept;
+    size_type max_size() const noexcept;
+
+    // modifiers:
+    template <class... Args>
+        pair<iterator, bool> emplace(Args&&... args);
+    template <class... Args>
+        iterator emplace_hint(const_iterator position, Args&&... args);
+    pair<iterator,bool> insert(const value_type& v);
+    pair<iterator,bool> insert(value_type&& v);
+    iterator insert(const_iterator position, const value_type& v);
+    iterator insert(const_iterator position, value_type&& v);
+    template <class InputIterator>
+        void insert(InputIterator first, InputIterator last);
+    void insert(initializer_list<value_type> il);
+
+    node_type extract(const_iterator position);                                       // C++17
+    node_type extract(const key_type& x);                                             // C++17
+    insert_return_type insert(node_type&& nh);                                        // C++17
+    iterator insert(const_iterator hint, node_type&& nh);                             // C++17
+
+    iterator  erase(const_iterator position);
+    iterator  erase(iterator position);  // C++14
+    size_type erase(const key_type& k);
+    iterator  erase(const_iterator first, const_iterator last);
+    void clear() noexcept;
+
+    template<class C2>
+      void merge(set<Key, C2, Allocator>& source);         // C++17
+    template<class C2>
+      void merge(set<Key, C2, Allocator>&& source);        // C++17
+    template<class C2>
+      void merge(multiset<Key, C2, Allocator>& source);    // C++17
+    template<class C2>
+      void merge(multiset<Key, C2, Allocator>&& source);   // C++17
+
+    void swap(set& s)
+        noexcept(
+            __is_nothrow_swappable<key_compare>::value &&
+            (!allocator_type::propagate_on_container_swap::value ||
+             __is_nothrow_swappable<allocator_type>::value));
+
+    // observers:
+    allocator_type get_allocator() const noexcept;
+    key_compare    key_comp()      const;
+    value_compare  value_comp()    const;
+
+    // set operations:
+          iterator find(const key_type& k);
+    const_iterator find(const key_type& k) const;
+    template<typename K>
+        iterator find(const K& x);
+    template<typename K>
+        const_iterator find(const K& x) const;  // C++14
+
+    template<typename K>
+        size_type count(const K& x) const;        // C++14
+    size_type      count(const key_type& k) const;
+
+        bool contains(const key_type& x) const; // C++20
+    template<class K> bool contains(const K& x) const; // C++20
+
+          iterator lower_bound(const key_type& k);
+    const_iterator lower_bound(const key_type& k) const;
+    template<typename K>
+        iterator lower_bound(const K& x);              // C++14
+    template<typename K>
+        const_iterator lower_bound(const K& x) const;  // C++14
+
+          iterator upper_bound(const key_type& k);
+    const_iterator upper_bound(const key_type& k) const;
+    template<typename K>
+        iterator upper_bound(const K& x);              // C++14
+    template<typename K>
+        const_iterator upper_bound(const K& x) const;  // C++14
+    pair<iterator,iterator>             equal_range(const key_type& k);
+    pair<const_iterator,const_iterator> equal_range(const key_type& k) const;
+    template<typename K>
+        pair<iterator,iterator>             equal_range(const K& x);        // C++14
+    template<typename K>
+        pair<const_iterator,const_iterator> equal_range(const K& x) const;  // C++14
+};
+
+template <class Key, class Compare, class Allocator>
+bool
+operator==(const set<Key, Compare, Allocator>& x,
+           const set<Key, Compare, Allocator>& y);
+
+template <class Key, class Compare, class Allocator>
+bool
+operator< (const set<Key, Compare, Allocator>& x,
+           const set<Key, Compare, Allocator>& y);
+
+template <class Key, class Compare, class Allocator>
+bool
+operator!=(const set<Key, Compare, Allocator>& x,
+           const set<Key, Compare, Allocator>& y);
+
+template <class Key, class Compare, class Allocator>
+bool
+operator> (const set<Key, Compare, Allocator>& x,
+           const set<Key, Compare, Allocator>& y);
+
+template <class Key, class Compare, class Allocator>
+bool
+operator>=(const set<Key, Compare, Allocator>& x,
+           const set<Key, Compare, Allocator>& y);
+
+template <class Key, class Compare, class Allocator>
+bool
+operator<=(const set<Key, Compare, Allocator>& x,
+           const set<Key, Compare, Allocator>& y);
+
+// specialized algorithms:
+template <class Key, class Compare, class Allocator>
+void
+swap(set<Key, Compare, Allocator>& x, set<Key, Compare, Allocator>& y)
+    noexcept(noexcept(x.swap(y)));
+
+template <class Key, class Compare, class Allocator, class Predicate>
+typename set<Key, Compare, Allocator>::size_type
+erase_if(set<Key, Compare, Allocator>& c, Predicate pred);  // C++20
+
+template <class Key, class Compare = less<Key>,
+          class Allocator = allocator<Key>>
+class multiset
+{
+public:
+    // types:
+    typedef Key                                      key_type;
+    typedef key_type                                 value_type;
+    typedef Compare                                  key_compare;
+    typedef key_compare                              value_compare;
+    typedef Allocator                                allocator_type;
+    typedef typename allocator_type::reference       reference;
+    typedef typename allocator_type::const_reference const_reference;
+    typedef typename allocator_type::size_type       size_type;
+    typedef typename allocator_type::difference_type difference_type;
+    typedef typename allocator_type::pointer         pointer;
+    typedef typename allocator_type::const_pointer   const_pointer;
+
+    typedef implementation-defined                   iterator;
+    typedef implementation-defined                   const_iterator;
+    typedef std::reverse_iterator<iterator>          reverse_iterator;
+    typedef std::reverse_iterator<const_iterator>    const_reverse_iterator;
+    typedef unspecified                              node_type;               // C++17
+
+    // construct/copy/destroy:
+    multiset()
+        noexcept(
+            is_nothrow_default_constructible<allocator_type>::value &&
+            is_nothrow_default_constructible<key_compare>::value &&
+            is_nothrow_copy_constructible<key_compare>::value);
+    explicit multiset(const value_compare& comp);
+    multiset(const value_compare& comp, const allocator_type& a);
+    template <class InputIterator>
+        multiset(InputIterator first, InputIterator last,
+                 const value_compare& comp = value_compare());
+    template <class InputIterator>
+        multiset(InputIterator first, InputIterator last,
+                 const value_compare& comp, const allocator_type& a);
+    multiset(const multiset& s);
+    multiset(multiset&& s)
+        noexcept(
+            is_nothrow_move_constructible<allocator_type>::value &&
+            is_nothrow_move_constructible<key_compare>::value);
+    explicit multiset(const allocator_type& a);
+    multiset(const multiset& s, const allocator_type& a);
+    multiset(multiset&& s, const allocator_type& a);
+    multiset(initializer_list<value_type> il, const value_compare& comp = value_compare());
+    multiset(initializer_list<value_type> il, const value_compare& comp,
+             const allocator_type& a);
+    template <class InputIterator>
+        multiset(InputIterator first, InputIterator last, const allocator_type& a)
+            : set(first, last, Compare(), a) {}  // C++14
+    multiset(initializer_list<value_type> il, const allocator_type& a)
+        : set(il, Compare(), a) {}  // C++14
+    ~multiset();
+
+    multiset& operator=(const multiset& s);
+    multiset& operator=(multiset&& s)
+        noexcept(
+            allocator_type::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<allocator_type>::value &&
+            is_nothrow_move_assignable<key_compare>::value);
+    multiset& operator=(initializer_list<value_type> il);
+
+    // iterators:
+          iterator begin() noexcept;
+    const_iterator begin() const noexcept;
+          iterator end() noexcept;
+    const_iterator end()   const noexcept;
+
+          reverse_iterator rbegin() noexcept;
+    const_reverse_iterator rbegin() const noexcept;
+          reverse_iterator rend() noexcept;
+    const_reverse_iterator rend()   const noexcept;
+
+    const_iterator         cbegin()  const noexcept;
+    const_iterator         cend()    const noexcept;
+    const_reverse_iterator crbegin() const noexcept;
+    const_reverse_iterator crend()   const noexcept;
+
+    // capacity:
+    bool      empty()    const noexcept;
+    size_type size()     const noexcept;
+    size_type max_size() const noexcept;
+
+    // modifiers:
+    template <class... Args>
+        iterator emplace(Args&&... args);
+    template <class... Args>
+        iterator emplace_hint(const_iterator position, Args&&... args);
+    iterator insert(const value_type& v);
+    iterator insert(value_type&& v);
+    iterator insert(const_iterator position, const value_type& v);
+    iterator insert(const_iterator position, value_type&& v);
+    template <class InputIterator>
+        void insert(InputIterator first, InputIterator last);
+    void insert(initializer_list<value_type> il);
+
+    node_type extract(const_iterator position);                                       // C++17
+    node_type extract(const key_type& x);                                             // C++17
+    iterator insert(node_type&& nh);                                                  // C++17
+    iterator insert(const_iterator hint, node_type&& nh);                             // C++17
+
+    iterator  erase(const_iterator position);
+    iterator  erase(iterator position);  // C++14
+    size_type erase(const key_type& k);
+    iterator  erase(const_iterator first, const_iterator last);
+    void clear() noexcept;
+
+    template<class C2>
+      void merge(multiset<Key, C2, Allocator>& source);    // C++17
+    template<class C2>
+      void merge(multiset<Key, C2, Allocator>&& source);   // C++17
+    template<class C2>
+      void merge(set<Key, C2, Allocator>& source);         // C++17
+    template<class C2>
+      void merge(set<Key, C2, Allocator>&& source);        // C++17
+
+    void swap(multiset& s)
+        noexcept(
+            __is_nothrow_swappable<key_compare>::value &&
+            (!allocator_type::propagate_on_container_swap::value ||
+             __is_nothrow_swappable<allocator_type>::value));
+
+    // observers:
+    allocator_type get_allocator() const noexcept;
+    key_compare    key_comp()      const;
+    value_compare  value_comp()    const;
+
+    // set operations:
+          iterator find(const key_type& k);
+    const_iterator find(const key_type& k) const;
+    template<typename K>
+        iterator find(const K& x);
+    template<typename K>
+        const_iterator find(const K& x) const;  // C++14
+
+    template<typename K>
+        size_type count(const K& x) const;      // C++14
+    size_type      count(const key_type& k) const;
+
+        bool contains(const key_type& x) const; // C++20
+    template<class K> bool contains(const K& x) const; // C++20
+
+          iterator lower_bound(const key_type& k);
+    const_iterator lower_bound(const key_type& k) const;
+    template<typename K>
+        iterator lower_bound(const K& x);              // C++14
+    template<typename K>
+        const_iterator lower_bound(const K& x) const;  // C++14
+
+          iterator upper_bound(const key_type& k);
+    const_iterator upper_bound(const key_type& k) const;
+    template<typename K>
+        iterator upper_bound(const K& x);              // C++14
+    template<typename K>
+        const_iterator upper_bound(const K& x) const;  // C++14
+
+    pair<iterator,iterator>             equal_range(const key_type& k);
+    pair<const_iterator,const_iterator> equal_range(const key_type& k) const;
+    template<typename K>
+        pair<iterator,iterator>             equal_range(const K& x);        // C++14
+    template<typename K>
+        pair<const_iterator,const_iterator> equal_range(const K& x) const;  // C++14
+};
+
+template <class Key, class Compare, class Allocator>
+bool
+operator==(const multiset<Key, Compare, Allocator>& x,
+           const multiset<Key, Compare, Allocator>& y);
+
+template <class Key, class Compare, class Allocator>
+bool
+operator< (const multiset<Key, Compare, Allocator>& x,
+           const multiset<Key, Compare, Allocator>& y);
+
+template <class Key, class Compare, class Allocator>
+bool
+operator!=(const multiset<Key, Compare, Allocator>& x,
+           const multiset<Key, Compare, Allocator>& y);
+
+template <class Key, class Compare, class Allocator>
+bool
+operator> (const multiset<Key, Compare, Allocator>& x,
+           const multiset<Key, Compare, Allocator>& y);
+
+template <class Key, class Compare, class Allocator>
+bool
+operator>=(const multiset<Key, Compare, Allocator>& x,
+           const multiset<Key, Compare, Allocator>& y);
+
+template <class Key, class Compare, class Allocator>
+bool
+operator<=(const multiset<Key, Compare, Allocator>& x,
+           const multiset<Key, Compare, Allocator>& y);
+
+// specialized algorithms:
+template <class Key, class Compare, class Allocator>
+void
+swap(multiset<Key, Compare, Allocator>& x, multiset<Key, Compare, Allocator>& y)
+    noexcept(noexcept(x.swap(y)));
+
+template <class Key, class Compare, class Allocator, class Predicate>
+typename multiset<Key, Compare, Allocator>::size_type
+erase_if(multiset<Key, Compare, Allocator>& c, Predicate pred);  // C++20
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__functional/is_transparent.h>
+#include <__node_handle>
+#include <__tree>
+#include <__utility/forward.h>
+#include <compare>
+#include <functional>
+#include <initializer_list>
+#include <iterator> // __libcpp_erase_if_container
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Key, class _Compare, class _Allocator>
+class multiset;
+
+template <class _Key, class _Compare = less<_Key>,
+          class _Allocator = allocator<_Key> >
+class _LIBCPP_TEMPLATE_VIS set
+{
+public:
+    // types:
+    typedef _Key                                     key_type;
+    typedef key_type                                 value_type;
+    typedef _Compare                                 key_compare;
+    typedef key_compare                              value_compare;
+    typedef __identity_t<_Allocator>                 allocator_type;
+    typedef value_type&                              reference;
+    typedef const value_type&                        const_reference;
+
+    static_assert((is_same<typename allocator_type::value_type, value_type>::value),
+                  "Allocator::value_type must be same type as value_type");
+
+private:
+    typedef __tree<value_type, value_compare, allocator_type> __base;
+    typedef allocator_traits<allocator_type>                  __alloc_traits;
+    typedef typename __base::__node_holder                    __node_holder;
+
+    __base __tree_;
+
+public:
+    typedef typename __base::pointer               pointer;
+    typedef typename __base::const_pointer         const_pointer;
+    typedef typename __base::size_type             size_type;
+    typedef typename __base::difference_type       difference_type;
+    typedef typename __base::const_iterator        iterator;
+    typedef typename __base::const_iterator        const_iterator;
+    typedef _VSTD::reverse_iterator<iterator>       reverse_iterator;
+    typedef _VSTD::reverse_iterator<const_iterator> const_reverse_iterator;
+
+#if _LIBCPP_STD_VER > 14
+    typedef __set_node_handle<typename __base::__node, allocator_type> node_type;
+    typedef __insert_return_type<iterator, node_type> insert_return_type;
+#endif
+
+    template <class _Key2, class _Compare2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS set;
+    template <class _Key2, class _Compare2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS multiset;
+
+    _LIBCPP_INLINE_VISIBILITY
+    set()
+        _NOEXCEPT_(
+            is_nothrow_default_constructible<allocator_type>::value &&
+            is_nothrow_default_constructible<key_compare>::value &&
+            is_nothrow_copy_constructible<key_compare>::value)
+        : __tree_(value_compare()) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit set(const value_compare& __comp)
+        _NOEXCEPT_(
+            is_nothrow_default_constructible<allocator_type>::value &&
+            is_nothrow_copy_constructible<key_compare>::value)
+        : __tree_(__comp) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit set(const value_compare& __comp, const allocator_type& __a)
+        : __tree_(__comp, __a) {}
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        set(_InputIterator __f, _InputIterator __l,
+            const value_compare& __comp = value_compare())
+        : __tree_(__comp)
+        {
+            insert(__f, __l);
+        }
+
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        set(_InputIterator __f, _InputIterator __l, const value_compare& __comp,
+            const allocator_type& __a)
+        : __tree_(__comp, __a)
+        {
+            insert(__f, __l);
+        }
+
+#if _LIBCPP_STD_VER > 11
+        template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        set(_InputIterator __f, _InputIterator __l, const allocator_type& __a)
+            : set(__f, __l, key_compare(), __a) {}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    set(const set& __s)
+        : __tree_(__s.__tree_)
+        {
+            insert(__s.begin(), __s.end());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    set& operator=(const set& __s)
+        {
+            __tree_ = __s.__tree_;
+            return *this;
+        }
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    set(set&& __s)
+        _NOEXCEPT_(is_nothrow_move_constructible<__base>::value)
+        : __tree_(_VSTD::move(__s.__tree_)) {}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit set(const allocator_type& __a)
+        : __tree_(__a) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    set(const set& __s, const allocator_type& __a)
+        : __tree_(__s.__tree_.value_comp(), __a)
+        {
+            insert(__s.begin(), __s.end());
+        }
+
+#ifndef _LIBCPP_CXX03_LANG
+    set(set&& __s, const allocator_type& __a);
+
+    _LIBCPP_INLINE_VISIBILITY
+    set(initializer_list<value_type> __il, const value_compare& __comp = value_compare())
+        : __tree_(__comp)
+        {
+            insert(__il.begin(), __il.end());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    set(initializer_list<value_type> __il, const value_compare& __comp,
+        const allocator_type& __a)
+        : __tree_(__comp, __a)
+        {
+            insert(__il.begin(), __il.end());
+        }
+
+#if _LIBCPP_STD_VER > 11
+    _LIBCPP_INLINE_VISIBILITY
+    set(initializer_list<value_type> __il, const allocator_type& __a)
+        : set(__il, key_compare(), __a) {}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    set& operator=(initializer_list<value_type> __il)
+        {
+            __tree_.__assign_unique(__il.begin(), __il.end());
+            return *this;
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    set& operator=(set&& __s)
+        _NOEXCEPT_(is_nothrow_move_assignable<__base>::value)
+        {
+            __tree_ = _VSTD::move(__s.__tree_);
+            return *this;
+        }
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~set() {
+        static_assert(sizeof(__diagnose_non_const_comparator<_Key, _Compare>()), "");
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+          iterator begin() _NOEXCEPT       {return __tree_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const _NOEXCEPT {return __tree_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+          iterator end() _NOEXCEPT         {return __tree_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()   const _NOEXCEPT {return __tree_.end();}
+
+    _LIBCPP_INLINE_VISIBILITY
+          reverse_iterator rbegin() _NOEXCEPT
+            {return reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rbegin() const _NOEXCEPT
+        {return const_reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+          reverse_iterator rend() _NOEXCEPT
+            {return reverse_iterator(begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rend() const _NOEXCEPT
+        {return const_reverse_iterator(begin());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin()  const _NOEXCEPT {return begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend() const _NOEXCEPT {return end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crbegin() const _NOEXCEPT {return rbegin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crend() const _NOEXCEPT {return rend();}
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT {return __tree_.size() == 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT {return __tree_.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT {return __tree_.max_size();}
+
+    // modifiers:
+#ifndef _LIBCPP_CXX03_LANG
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        pair<iterator, bool> emplace(_Args&&... __args)
+            {return __tree_.__emplace_unique(_VSTD::forward<_Args>(__args)...);}
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator emplace_hint(const_iterator __p, _Args&&... __args)
+            {return __tree_.__emplace_hint_unique(__p, _VSTD::forward<_Args>(__args)...);}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator,bool> insert(const value_type& __v)
+        {return __tree_.__insert_unique(__v);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, const value_type& __v)
+        {return __tree_.__insert_unique(__p, __v);}
+
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        void insert(_InputIterator __f, _InputIterator __l)
+        {
+            for (const_iterator __e = cend(); __f != __l; ++__f)
+                __tree_.__insert_unique(__e, *__f);
+        }
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator,bool> insert(value_type&& __v)
+        {return __tree_.__insert_unique(_VSTD::move(__v));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, value_type&& __v)
+        {return __tree_.__insert_unique(__p, _VSTD::move(__v));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void insert(initializer_list<value_type> __il)
+        {insert(__il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator  erase(const_iterator __p) {return __tree_.erase(__p);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type erase(const key_type& __k)
+        {return __tree_.__erase_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator  erase(const_iterator __f, const_iterator __l)
+        {return __tree_.erase(__f, __l);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT {__tree_.clear();}
+
+#if _LIBCPP_STD_VER > 14
+    _LIBCPP_INLINE_VISIBILITY
+    insert_return_type insert(node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to set::insert()");
+        return __tree_.template __node_handle_insert_unique<
+            node_type, insert_return_type>(_VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __hint, node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to set::insert()");
+        return __tree_.template __node_handle_insert_unique<node_type>(
+            __hint, _VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(key_type const& __key)
+    {
+        return __tree_.template __node_handle_extract<node_type>(__key);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(const_iterator __it)
+    {
+        return __tree_.template __node_handle_extract<node_type>(__it);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(set<key_type, _Compare2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __tree_.__node_handle_merge_unique(__source.__tree_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(set<key_type, _Compare2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __tree_.__node_handle_merge_unique(__source.__tree_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(multiset<key_type, _Compare2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __tree_.__node_handle_merge_unique(__source.__tree_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(multiset<key_type, _Compare2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __tree_.__node_handle_merge_unique(__source.__tree_);
+    }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(set& __s) _NOEXCEPT_(__is_nothrow_swappable<__base>::value)
+        {__tree_.swap(__s.__tree_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT {return __tree_.__alloc();}
+    _LIBCPP_INLINE_VISIBILITY
+    key_compare    key_comp()      const {return __tree_.value_comp();}
+    _LIBCPP_INLINE_VISIBILITY
+    value_compare  value_comp()    const {return __tree_.value_comp();}
+
+    // set operations:
+    _LIBCPP_INLINE_VISIBILITY
+    iterator find(const key_type& __k)             {return __tree_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const key_type& __k) const {return __tree_.find(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,iterator>::type
+    find(const _K2& __k)                           {return __tree_.find(__k);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,const_iterator>::type
+    find(const _K2& __k) const                     {return __tree_.find(__k);}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type      count(const key_type& __k) const
+        {return __tree_.__count_unique(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,size_type>::type
+    count(const _K2& __k) const                    {return __tree_.__count_multi(__k);}
+#endif
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const key_type& __k) const {return find(__k) != end();}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value, bool>::type
+    contains(const _K2& __k) const { return find(__k) != end(); }
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator lower_bound(const key_type& __k)
+        {return __tree_.lower_bound(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator lower_bound(const key_type& __k) const
+        {return __tree_.lower_bound(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,iterator>::type
+    lower_bound(const _K2& __k)       {return __tree_.lower_bound(__k);}
+
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,const_iterator>::type
+    lower_bound(const _K2& __k) const {return __tree_.lower_bound(__k);}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator upper_bound(const key_type& __k)
+        {return __tree_.upper_bound(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator upper_bound(const key_type& __k) const
+        {return __tree_.upper_bound(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,iterator>::type
+    upper_bound(const _K2& __k)       {return __tree_.upper_bound(__k);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,const_iterator>::type
+    upper_bound(const _K2& __k) const {return __tree_.upper_bound(__k);}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator,iterator> equal_range(const key_type& __k)
+        {return __tree_.__equal_range_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    pair<const_iterator,const_iterator> equal_range(const key_type& __k) const
+        {return __tree_.__equal_range_unique(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,pair<iterator,iterator>>::type
+    equal_range(const _K2& __k)       {return __tree_.__equal_range_multi(__k);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,pair<const_iterator,const_iterator>>::type
+    equal_range(const _K2& __k) const {return __tree_.__equal_range_multi(__k);}
+#endif
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator,
+         class _Compare = less<__iter_value_type<_InputIterator>>,
+         class _Allocator = allocator<__iter_value_type<_InputIterator>>,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>,
+         class = enable_if_t<!__is_allocator<_Compare>::value, void>>
+set(_InputIterator, _InputIterator, _Compare = _Compare(), _Allocator = _Allocator())
+  -> set<__iter_value_type<_InputIterator>, _Compare, _Allocator>;
+
+template<class _Key, class _Compare = less<_Key>,
+         class _Allocator = allocator<_Key>,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>,
+         class = enable_if_t<!__is_allocator<_Compare>::value, void>>
+set(initializer_list<_Key>, _Compare = _Compare(), _Allocator = _Allocator())
+  -> set<_Key, _Compare, _Allocator>;
+
+template<class _InputIterator, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>>
+set(_InputIterator, _InputIterator, _Allocator)
+  -> set<__iter_value_type<_InputIterator>,
+         less<__iter_value_type<_InputIterator>>, _Allocator>;
+
+template<class _Key, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>>
+set(initializer_list<_Key>, _Allocator)
+  -> set<_Key, less<_Key>, _Allocator>;
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Key, class _Compare, class _Allocator>
+set<_Key, _Compare, _Allocator>::set(set&& __s, const allocator_type& __a)
+    : __tree_(_VSTD::move(__s.__tree_), __a)
+{
+    if (__a != __s.get_allocator())
+    {
+        const_iterator __e = cend();
+        while (!__s.empty())
+            insert(__e, _VSTD::move(__s.__tree_.remove(__s.begin())->__value_));
+    }
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const set<_Key, _Compare, _Allocator>& __x,
+           const set<_Key, _Compare, _Allocator>& __y)
+{
+    return __x.size() == __y.size() && _VSTD::equal(__x.begin(), __x.end(), __y.begin());
+}
+
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const set<_Key, _Compare, _Allocator>& __x,
+           const set<_Key, _Compare, _Allocator>& __y)
+{
+    return _VSTD::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
+}
+
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const set<_Key, _Compare, _Allocator>& __x,
+           const set<_Key, _Compare, _Allocator>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const set<_Key, _Compare, _Allocator>& __x,
+           const set<_Key, _Compare, _Allocator>& __y)
+{
+    return __y < __x;
+}
+
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const set<_Key, _Compare, _Allocator>& __x,
+           const set<_Key, _Compare, _Allocator>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const set<_Key, _Compare, _Allocator>& __x,
+           const set<_Key, _Compare, _Allocator>& __y)
+{
+    return !(__y < __x);
+}
+
+// specialized algorithms:
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(set<_Key, _Compare, _Allocator>& __x,
+     set<_Key, _Compare, _Allocator>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Key, class _Compare, class _Allocator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+    typename set<_Key, _Compare, _Allocator>::size_type
+    erase_if(set<_Key, _Compare, _Allocator>& __c, _Predicate __pred) {
+  return _VSTD::__libcpp_erase_if_container(__c, __pred);
+}
+#endif
+
+template <class _Key, class _Compare = less<_Key>,
+          class _Allocator = allocator<_Key> >
+class _LIBCPP_TEMPLATE_VIS multiset
+{
+public:
+    // types:
+    typedef _Key                                      key_type;
+    typedef key_type                                 value_type;
+    typedef _Compare                                  key_compare;
+    typedef key_compare                              value_compare;
+    typedef __identity_t<_Allocator>                 allocator_type;
+    typedef value_type&                              reference;
+    typedef const value_type&                        const_reference;
+
+    static_assert((is_same<typename allocator_type::value_type, value_type>::value),
+                  "Allocator::value_type must be same type as value_type");
+
+private:
+    typedef __tree<value_type, value_compare, allocator_type> __base;
+    typedef allocator_traits<allocator_type>                  __alloc_traits;
+    typedef typename __base::__node_holder                    __node_holder;
+
+    __base __tree_;
+
+public:
+    typedef typename __base::pointer               pointer;
+    typedef typename __base::const_pointer         const_pointer;
+    typedef typename __base::size_type             size_type;
+    typedef typename __base::difference_type       difference_type;
+    typedef typename __base::const_iterator        iterator;
+    typedef typename __base::const_iterator        const_iterator;
+    typedef _VSTD::reverse_iterator<iterator>       reverse_iterator;
+    typedef _VSTD::reverse_iterator<const_iterator> const_reverse_iterator;
+
+#if _LIBCPP_STD_VER > 14
+    typedef __set_node_handle<typename __base::__node, allocator_type> node_type;
+#endif
+
+    template <class _Key2, class _Compare2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS set;
+    template <class _Key2, class _Compare2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS multiset;
+
+    // construct/copy/destroy:
+    _LIBCPP_INLINE_VISIBILITY
+    multiset()
+        _NOEXCEPT_(
+            is_nothrow_default_constructible<allocator_type>::value &&
+            is_nothrow_default_constructible<key_compare>::value &&
+            is_nothrow_copy_constructible<key_compare>::value)
+        : __tree_(value_compare()) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit multiset(const value_compare& __comp)
+        _NOEXCEPT_(
+            is_nothrow_default_constructible<allocator_type>::value &&
+            is_nothrow_copy_constructible<key_compare>::value)
+        : __tree_(__comp) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit multiset(const value_compare& __comp, const allocator_type& __a)
+        : __tree_(__comp, __a) {}
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        multiset(_InputIterator __f, _InputIterator __l,
+                 const value_compare& __comp = value_compare())
+        : __tree_(__comp)
+        {
+            insert(__f, __l);
+        }
+
+#if _LIBCPP_STD_VER > 11
+        template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        multiset(_InputIterator __f, _InputIterator __l, const allocator_type& __a)
+            : multiset(__f, __l, key_compare(), __a) {}
+#endif
+
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        multiset(_InputIterator __f, _InputIterator __l,
+                 const value_compare& __comp, const allocator_type& __a)
+        : __tree_(__comp, __a)
+        {
+            insert(__f, __l);
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    multiset(const multiset& __s)
+        : __tree_(__s.__tree_.value_comp(),
+          __alloc_traits::select_on_container_copy_construction(__s.__tree_.__alloc()))
+        {
+            insert(__s.begin(), __s.end());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    multiset& operator=(const multiset& __s)
+        {
+            __tree_ = __s.__tree_;
+            return *this;
+        }
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    multiset(multiset&& __s)
+        _NOEXCEPT_(is_nothrow_move_constructible<__base>::value)
+        : __tree_(_VSTD::move(__s.__tree_)) {}
+
+    multiset(multiset&& __s, const allocator_type& __a);
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    explicit multiset(const allocator_type& __a)
+        : __tree_(__a) {}
+    _LIBCPP_INLINE_VISIBILITY
+    multiset(const multiset& __s, const allocator_type& __a)
+        : __tree_(__s.__tree_.value_comp(), __a)
+        {
+            insert(__s.begin(), __s.end());
+        }
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    multiset(initializer_list<value_type> __il, const value_compare& __comp = value_compare())
+        : __tree_(__comp)
+        {
+            insert(__il.begin(), __il.end());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    multiset(initializer_list<value_type> __il, const value_compare& __comp,
+        const allocator_type& __a)
+        : __tree_(__comp, __a)
+        {
+            insert(__il.begin(), __il.end());
+        }
+
+#if _LIBCPP_STD_VER > 11
+    _LIBCPP_INLINE_VISIBILITY
+    multiset(initializer_list<value_type> __il, const allocator_type& __a)
+        : multiset(__il, key_compare(), __a) {}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    multiset& operator=(initializer_list<value_type> __il)
+        {
+            __tree_.__assign_multi(__il.begin(), __il.end());
+            return *this;
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    multiset& operator=(multiset&& __s)
+        _NOEXCEPT_(is_nothrow_move_assignable<__base>::value)
+        {
+            __tree_ = _VSTD::move(__s.__tree_);
+            return *this;
+        }
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~multiset() {
+        static_assert(sizeof(__diagnose_non_const_comparator<_Key, _Compare>()), "");
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+          iterator begin() _NOEXCEPT       {return __tree_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const _NOEXCEPT {return __tree_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+          iterator end() _NOEXCEPT         {return __tree_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()   const _NOEXCEPT {return __tree_.end();}
+
+    _LIBCPP_INLINE_VISIBILITY
+          reverse_iterator rbegin() _NOEXCEPT
+            {return reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rbegin() const _NOEXCEPT
+        {return const_reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+          reverse_iterator rend() _NOEXCEPT
+            {return       reverse_iterator(begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rend() const _NOEXCEPT
+        {return const_reverse_iterator(begin());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin()  const _NOEXCEPT {return begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend() const _NOEXCEPT {return end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crbegin() const _NOEXCEPT {return rbegin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crend() const _NOEXCEPT {return rend();}
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT {return __tree_.size() == 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT {return __tree_.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT {return __tree_.max_size();}
+
+    // modifiers:
+#ifndef _LIBCPP_CXX03_LANG
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator emplace(_Args&&... __args)
+            {return __tree_.__emplace_multi(_VSTD::forward<_Args>(__args)...);}
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator emplace_hint(const_iterator __p, _Args&&... __args)
+            {return __tree_.__emplace_hint_multi(__p, _VSTD::forward<_Args>(__args)...);}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const value_type& __v)
+        {return __tree_.__insert_multi(__v);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, const value_type& __v)
+        {return __tree_.__insert_multi(__p, __v);}
+
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        void insert(_InputIterator __f, _InputIterator __l)
+        {
+            for (const_iterator __e = cend(); __f != __l; ++__f)
+                __tree_.__insert_multi(__e, *__f);
+        }
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(value_type&& __v)
+        {return __tree_.__insert_multi(_VSTD::move(__v));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, value_type&& __v)
+        {return __tree_.__insert_multi(__p, _VSTD::move(__v));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void insert(initializer_list<value_type> __il)
+        {insert(__il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator  erase(const_iterator __p) {return __tree_.erase(__p);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type erase(const key_type& __k) {return __tree_.__erase_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator  erase(const_iterator __f, const_iterator __l)
+        {return __tree_.erase(__f, __l);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT {__tree_.clear();}
+
+#if _LIBCPP_STD_VER > 14
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to multiset::insert()");
+        return __tree_.template __node_handle_insert_multi<node_type>(
+            _VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __hint, node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to multiset::insert()");
+        return __tree_.template __node_handle_insert_multi<node_type>(
+            __hint, _VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(key_type const& __key)
+    {
+        return __tree_.template __node_handle_extract<node_type>(__key);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(const_iterator __it)
+    {
+        return __tree_.template __node_handle_extract<node_type>(__it);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(multiset<key_type, _Compare2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __tree_.__node_handle_merge_multi(__source.__tree_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(multiset<key_type, _Compare2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __tree_.__node_handle_merge_multi(__source.__tree_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(set<key_type, _Compare2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __tree_.__node_handle_merge_multi(__source.__tree_);
+    }
+    template <class _Compare2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(set<key_type, _Compare2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __tree_.__node_handle_merge_multi(__source.__tree_);
+    }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(multiset& __s)
+        _NOEXCEPT_(__is_nothrow_swappable<__base>::value)
+        {__tree_.swap(__s.__tree_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT {return __tree_.__alloc();}
+    _LIBCPP_INLINE_VISIBILITY
+    key_compare    key_comp()      const {return __tree_.value_comp();}
+    _LIBCPP_INLINE_VISIBILITY
+    value_compare  value_comp()    const {return __tree_.value_comp();}
+
+    // set operations:
+    _LIBCPP_INLINE_VISIBILITY
+    iterator find(const key_type& __k)             {return __tree_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const key_type& __k) const {return __tree_.find(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,iterator>::type
+    find(const _K2& __k)                           {return __tree_.find(__k);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,const_iterator>::type
+    find(const _K2& __k) const                     {return __tree_.find(__k);}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type      count(const key_type& __k) const
+        {return __tree_.__count_multi(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,size_type>::type
+    count(const _K2& __k) const            {return __tree_.__count_multi(__k);}
+#endif
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const key_type& __k) const {return find(__k) != end();}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value, bool>::type
+    contains(const _K2& __k) const { return find(__k) != end(); }
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator lower_bound(const key_type& __k)
+        {return __tree_.lower_bound(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator lower_bound(const key_type& __k) const
+            {return __tree_.lower_bound(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,iterator>::type
+    lower_bound(const _K2& __k)       {return __tree_.lower_bound(__k);}
+
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,const_iterator>::type
+    lower_bound(const _K2& __k) const {return __tree_.lower_bound(__k);}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator upper_bound(const key_type& __k)
+            {return __tree_.upper_bound(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator upper_bound(const key_type& __k) const
+            {return __tree_.upper_bound(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,iterator>::type
+    upper_bound(const _K2& __k)       {return __tree_.upper_bound(__k);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,const_iterator>::type
+    upper_bound(const _K2& __k) const {return __tree_.upper_bound(__k);}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator,iterator>             equal_range(const key_type& __k)
+            {return __tree_.__equal_range_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    pair<const_iterator,const_iterator> equal_range(const key_type& __k) const
+            {return __tree_.__equal_range_multi(__k);}
+#if _LIBCPP_STD_VER > 11
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,pair<iterator,iterator>>::type
+    equal_range(const _K2& __k)       {return __tree_.__equal_range_multi(__k);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    typename enable_if<__is_transparent<_Compare, _K2>::value,pair<const_iterator,const_iterator>>::type
+    equal_range(const _K2& __k) const {return __tree_.__equal_range_multi(__k);}
+#endif
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator,
+         class _Compare = less<__iter_value_type<_InputIterator>>,
+         class _Allocator = allocator<__iter_value_type<_InputIterator>>,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>,
+         class = enable_if_t<!__is_allocator<_Compare>::value, void>>
+multiset(_InputIterator, _InputIterator, _Compare = _Compare(), _Allocator = _Allocator())
+  -> multiset<__iter_value_type<_InputIterator>, _Compare, _Allocator>;
+
+template<class _Key, class _Compare = less<_Key>,
+         class _Allocator = allocator<_Key>,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>,
+         class = enable_if_t<!__is_allocator<_Compare>::value, void>>
+multiset(initializer_list<_Key>, _Compare = _Compare(), _Allocator = _Allocator())
+  -> multiset<_Key, _Compare, _Allocator>;
+
+template<class _InputIterator, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>>
+multiset(_InputIterator, _InputIterator, _Allocator)
+  -> multiset<__iter_value_type<_InputIterator>,
+         less<__iter_value_type<_InputIterator>>, _Allocator>;
+
+template<class _Key, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value, void>>
+multiset(initializer_list<_Key>, _Allocator)
+  -> multiset<_Key, less<_Key>, _Allocator>;
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Key, class _Compare, class _Allocator>
+multiset<_Key, _Compare, _Allocator>::multiset(multiset&& __s, const allocator_type& __a)
+    : __tree_(_VSTD::move(__s.__tree_), __a)
+{
+    if (__a != __s.get_allocator())
+    {
+        const_iterator __e = cend();
+        while (!__s.empty())
+            insert(__e, _VSTD::move(__s.__tree_.remove(__s.begin())->__value_));
+    }
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const multiset<_Key, _Compare, _Allocator>& __x,
+           const multiset<_Key, _Compare, _Allocator>& __y)
+{
+    return __x.size() == __y.size() && _VSTD::equal(__x.begin(), __x.end(), __y.begin());
+}
+
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const multiset<_Key, _Compare, _Allocator>& __x,
+           const multiset<_Key, _Compare, _Allocator>& __y)
+{
+    return _VSTD::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
+}
+
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const multiset<_Key, _Compare, _Allocator>& __x,
+           const multiset<_Key, _Compare, _Allocator>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const multiset<_Key, _Compare, _Allocator>& __x,
+           const multiset<_Key, _Compare, _Allocator>& __y)
+{
+    return __y < __x;
+}
+
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const multiset<_Key, _Compare, _Allocator>& __x,
+           const multiset<_Key, _Compare, _Allocator>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const multiset<_Key, _Compare, _Allocator>& __x,
+           const multiset<_Key, _Compare, _Allocator>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _Key, class _Compare, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(multiset<_Key, _Compare, _Allocator>& __x,
+     multiset<_Key, _Compare, _Allocator>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Key, class _Compare, class _Allocator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+    typename multiset<_Key, _Compare, _Allocator>::size_type
+    erase_if(multiset<_Key, _Compare, _Allocator>& __c, _Predicate __pred) {
+  return _VSTD::__libcpp_erase_if_container(__c, __pred);
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_SET
diff --git a/contrib/libs/cxxsupp/libcxx/include/setjmp.h b/contrib/libs/cxxsupp/libcxx/include/setjmp.h
new file mode 100644
index 00000000000..f31aefb5f82
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/setjmp.h
@@ -0,0 +1,48 @@
+// -*- C++ -*-
+//===--------------------------- setjmp.h ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SETJMP_H
+#define _LIBCPP_SETJMP_H
+
+/*
+    setjmp.h synopsis
+
+Macros:
+
+    setjmp
+
+Types:
+
+    jmp_buf
+
+void longjmp(jmp_buf env, int val);
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_MSVC_INCLUDE(setjmp.h)
+#else
+#include_next <setjmp.h>
+#endif
+
+#ifdef __cplusplus
+
+#ifndef setjmp
+#define setjmp(env) setjmp(env)
+#endif
+
+#endif // __cplusplus
+
+#endif // _LIBCPP_SETJMP_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/shared_mutex b/contrib/libs/cxxsupp/libcxx/include/shared_mutex
new file mode 100644
index 00000000000..8205c3e0af0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/shared_mutex
@@ -0,0 +1,509 @@
+// -*- C++ -*-
+//===------------------------ shared_mutex --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SHARED_MUTEX
+#define _LIBCPP_SHARED_MUTEX
+
+/*
+    shared_mutex synopsis
+
+// C++1y
+
+namespace std
+{
+
+class shared_mutex      // C++17
+{
+public:
+    shared_mutex();
+    ~shared_mutex();
+
+    shared_mutex(const shared_mutex&) = delete;
+    shared_mutex& operator=(const shared_mutex&) = delete;
+
+    // Exclusive ownership
+    void lock(); // blocking
+    bool try_lock();
+    void unlock();
+
+    // Shared ownership
+    void lock_shared(); // blocking
+    bool try_lock_shared();
+    void unlock_shared();
+
+    typedef implementation-defined native_handle_type; // See 30.2.3
+    native_handle_type native_handle(); // See 30.2.3
+};
+
+class shared_timed_mutex
+{
+public:
+    shared_timed_mutex();
+    ~shared_timed_mutex();
+
+    shared_timed_mutex(const shared_timed_mutex&) = delete;
+    shared_timed_mutex& operator=(const shared_timed_mutex&) = delete;
+
+    // Exclusive ownership
+    void lock(); // blocking
+    bool try_lock();
+    template <class Rep, class Period>
+        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
+    template <class Clock, class Duration>
+        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
+    void unlock();
+
+    // Shared ownership
+    void lock_shared(); // blocking
+    bool try_lock_shared();
+    template <class Rep, class Period>
+        bool
+        try_lock_shared_for(const chrono::duration<Rep, Period>& rel_time);
+    template <class Clock, class Duration>
+        bool
+        try_lock_shared_until(const chrono::time_point<Clock, Duration>& abs_time);
+    void unlock_shared();
+};
+
+template <class Mutex>
+class shared_lock
+{
+public:
+    typedef Mutex mutex_type;
+
+    // Shared locking
+    shared_lock() noexcept;
+    explicit shared_lock(mutex_type& m); // blocking
+    shared_lock(mutex_type& m, defer_lock_t) noexcept;
+    shared_lock(mutex_type& m, try_to_lock_t);
+    shared_lock(mutex_type& m, adopt_lock_t);
+    template <class Clock, class Duration>
+        shared_lock(mutex_type& m,
+                    const chrono::time_point<Clock, Duration>& abs_time);
+    template <class Rep, class Period>
+        shared_lock(mutex_type& m,
+                    const chrono::duration<Rep, Period>& rel_time);
+    ~shared_lock();
+
+    shared_lock(shared_lock const&) = delete;
+    shared_lock& operator=(shared_lock const&) = delete;
+
+    shared_lock(shared_lock&& u) noexcept;
+    shared_lock& operator=(shared_lock&& u) noexcept;
+
+    void lock(); // blocking
+    bool try_lock();
+    template <class Rep, class Period>
+        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
+    template <class Clock, class Duration>
+        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
+    void unlock();
+
+    // Setters
+    void swap(shared_lock& u) noexcept;
+    mutex_type* release() noexcept;
+
+    // Getters
+    bool owns_lock() const noexcept;
+    explicit operator bool () const noexcept;
+    mutex_type* mutex() const noexcept;
+};
+
+template <class Mutex>
+    void swap(shared_lock<Mutex>& x, shared_lock<Mutex>& y) noexcept;
+
+}  // std
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <version>
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+#if _LIBCPP_STD_VER > 11 || defined(_LIBCPP_BUILDING_LIBRARY)
+
+#include <__mutex_base>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_HAS_NO_THREADS
+#error <shared_mutex> is not supported on this single threaded system
+#else // !_LIBCPP_HAS_NO_THREADS
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+struct _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_SHARED_MUTEX _LIBCPP_THREAD_SAFETY_ANNOTATION(capability("shared_mutex"))
+__shared_mutex_base
+{
+    mutex               __mut_;
+    condition_variable  __gate1_;
+    condition_variable  __gate2_;
+    unsigned            __state_;
+
+    static const unsigned __write_entered_ = 1U << (sizeof(unsigned)*__CHAR_BIT__ - 1);
+    static const unsigned __n_readers_ = ~__write_entered_;
+
+    __shared_mutex_base();
+    _LIBCPP_INLINE_VISIBILITY ~__shared_mutex_base() = default;
+
+    __shared_mutex_base(const __shared_mutex_base&) = delete;
+    __shared_mutex_base& operator=(const __shared_mutex_base&) = delete;
+
+    // Exclusive ownership
+    void lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability()); // blocking
+    bool try_lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(try_acquire_capability(true));
+    void unlock() _LIBCPP_THREAD_SAFETY_ANNOTATION(release_capability());
+
+    // Shared ownership
+    void lock_shared() _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_shared_capability()); // blocking
+    bool try_lock_shared() _LIBCPP_THREAD_SAFETY_ANNOTATION(try_acquire_shared_capability(true));
+    void unlock_shared() _LIBCPP_THREAD_SAFETY_ANNOTATION(release_shared_capability());
+
+//     typedef implementation-defined native_handle_type; // See 30.2.3
+//     native_handle_type native_handle(); // See 30.2.3
+};
+
+
+#if _LIBCPP_STD_VER > 14
+class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_SHARED_MUTEX shared_mutex
+{
+    __shared_mutex_base __base;
+public:
+    _LIBCPP_INLINE_VISIBILITY shared_mutex() : __base() {}
+    _LIBCPP_INLINE_VISIBILITY ~shared_mutex() = default;
+
+    shared_mutex(const shared_mutex&) = delete;
+    shared_mutex& operator=(const shared_mutex&) = delete;
+
+    // Exclusive ownership
+    _LIBCPP_INLINE_VISIBILITY void lock()     { return __base.lock(); }
+    _LIBCPP_INLINE_VISIBILITY bool try_lock() { return __base.try_lock(); }
+    _LIBCPP_INLINE_VISIBILITY void unlock()   { return __base.unlock(); }
+
+    // Shared ownership
+    _LIBCPP_INLINE_VISIBILITY void lock_shared()     { return __base.lock_shared(); }
+    _LIBCPP_INLINE_VISIBILITY bool try_lock_shared() { return __base.try_lock_shared(); }
+    _LIBCPP_INLINE_VISIBILITY void unlock_shared()   { return __base.unlock_shared(); }
+
+//     typedef __shared_mutex_base::native_handle_type native_handle_type;
+//     _LIBCPP_INLINE_VISIBILITY native_handle_type native_handle() { return __base::unlock_shared(); }
+};
+#endif
+
+
+class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_SHARED_MUTEX shared_timed_mutex
+{
+    __shared_mutex_base __base;
+public:
+    shared_timed_mutex();
+    _LIBCPP_INLINE_VISIBILITY ~shared_timed_mutex() = default;
+
+    shared_timed_mutex(const shared_timed_mutex&) = delete;
+    shared_timed_mutex& operator=(const shared_timed_mutex&) = delete;
+
+    // Exclusive ownership
+    void lock();
+    bool try_lock();
+    template <class _Rep, class _Period>
+        _LIBCPP_INLINE_VISIBILITY
+        bool
+        try_lock_for(const chrono::duration<_Rep, _Period>& __rel_time)
+        {
+            return try_lock_until(chrono::steady_clock::now() + __rel_time);
+        }
+    template <class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        bool
+        try_lock_until(const chrono::time_point<_Clock, _Duration>& __abs_time);
+    void unlock();
+
+    // Shared ownership
+    void lock_shared();
+    bool try_lock_shared();
+    template <class _Rep, class _Period>
+        _LIBCPP_INLINE_VISIBILITY
+        bool
+        try_lock_shared_for(const chrono::duration<_Rep, _Period>& __rel_time)
+        {
+            return try_lock_shared_until(chrono::steady_clock::now() + __rel_time);
+        }
+    template <class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        bool
+        try_lock_shared_until(const chrono::time_point<_Clock, _Duration>& __abs_time);
+    void unlock_shared();
+};
+
+template <class _Clock, class _Duration>
+bool
+shared_timed_mutex::try_lock_until(
+                        const chrono::time_point<_Clock, _Duration>& __abs_time)
+{
+    unique_lock<mutex> __lk(__base.__mut_);
+    if (__base.__state_ & __base.__write_entered_)
+    {
+        while (true)
+        {
+            cv_status __status = __base.__gate1_.wait_until(__lk, __abs_time);
+            if ((__base.__state_ & __base.__write_entered_) == 0)
+                break;
+            if (__status == cv_status::timeout)
+                return false;
+        }
+    }
+    __base.__state_ |= __base.__write_entered_;
+    if (__base.__state_ & __base.__n_readers_)
+    {
+        while (true)
+        {
+            cv_status __status = __base.__gate2_.wait_until(__lk, __abs_time);
+            if ((__base.__state_ & __base.__n_readers_) == 0)
+                break;
+            if (__status == cv_status::timeout)
+            {
+                __base.__state_ &= ~__base.__write_entered_;
+                __base.__gate1_.notify_all();
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
+template <class _Clock, class _Duration>
+bool
+shared_timed_mutex::try_lock_shared_until(
+                        const chrono::time_point<_Clock, _Duration>& __abs_time)
+{
+    unique_lock<mutex> __lk(__base.__mut_);
+    if ((__base.__state_ & __base.__write_entered_) || (__base.__state_ & __base.__n_readers_) == __base.__n_readers_)
+    {
+        while (true)
+        {
+            cv_status status = __base.__gate1_.wait_until(__lk, __abs_time);
+            if ((__base.__state_ & __base.__write_entered_) == 0 &&
+                                       (__base.__state_ & __base.__n_readers_) < __base.__n_readers_)
+                break;
+            if (status == cv_status::timeout)
+                return false;
+        }
+    }
+    unsigned __num_readers = (__base.__state_ & __base.__n_readers_) + 1;
+    __base.__state_ &= ~__base.__n_readers_;
+    __base.__state_ |= __num_readers;
+    return true;
+}
+
+template <class _Mutex>
+class shared_lock
+{
+public:
+    typedef _Mutex mutex_type;
+
+private:
+    mutex_type* __m_;
+    bool __owns_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    shared_lock() _NOEXCEPT
+        : __m_(nullptr),
+          __owns_(false)
+        {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit shared_lock(mutex_type& __m)
+        : __m_(_VSTD::addressof(__m)),
+          __owns_(true)
+        {__m_->lock_shared();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    shared_lock(mutex_type& __m, defer_lock_t) _NOEXCEPT
+        : __m_(_VSTD::addressof(__m)),
+          __owns_(false)
+        {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    shared_lock(mutex_type& __m, try_to_lock_t)
+        : __m_(_VSTD::addressof(__m)),
+          __owns_(__m.try_lock_shared())
+        {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    shared_lock(mutex_type& __m, adopt_lock_t)
+        : __m_(_VSTD::addressof(__m)),
+          __owns_(true)
+        {}
+
+    template <class _Clock, class _Duration>
+        _LIBCPP_INLINE_VISIBILITY
+        shared_lock(mutex_type& __m,
+                    const chrono::time_point<_Clock, _Duration>& __abs_time)
+            : __m_(_VSTD::addressof(__m)),
+              __owns_(__m.try_lock_shared_until(__abs_time))
+            {}
+
+    template <class _Rep, class _Period>
+        _LIBCPP_INLINE_VISIBILITY
+        shared_lock(mutex_type& __m,
+                    const chrono::duration<_Rep, _Period>& __rel_time)
+            : __m_(_VSTD::addressof(__m)),
+              __owns_(__m.try_lock_shared_for(__rel_time))
+            {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~shared_lock()
+    {
+        if (__owns_)
+            __m_->unlock_shared();
+    }
+
+    shared_lock(shared_lock const&) = delete;
+    shared_lock& operator=(shared_lock const&) = delete;
+
+    _LIBCPP_INLINE_VISIBILITY
+    shared_lock(shared_lock&& __u) _NOEXCEPT
+        : __m_(__u.__m_),
+          __owns_(__u.__owns_)
+        {
+            __u.__m_ = nullptr;
+            __u.__owns_ = false;
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    shared_lock& operator=(shared_lock&& __u) _NOEXCEPT
+    {
+        if (__owns_)
+            __m_->unlock_shared();
+        __m_ = nullptr;
+        __owns_ = false;
+        __m_ = __u.__m_;
+        __owns_ = __u.__owns_;
+        __u.__m_ = nullptr;
+        __u.__owns_ = false;
+        return *this;
+    }
+
+    void lock();
+    bool try_lock();
+    template <class Rep, class Period>
+        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
+    template <class Clock, class Duration>
+        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
+    void unlock();
+
+    // Setters
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(shared_lock& __u) _NOEXCEPT
+    {
+        _VSTD::swap(__m_, __u.__m_);
+        _VSTD::swap(__owns_, __u.__owns_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    mutex_type* release() _NOEXCEPT
+    {
+        mutex_type* __m = __m_;
+        __m_ = nullptr;
+        __owns_ = false;
+        return __m;
+    }
+
+    // Getters
+    _LIBCPP_INLINE_VISIBILITY
+    bool owns_lock() const _NOEXCEPT {return __owns_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit operator bool () const _NOEXCEPT {return __owns_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    mutex_type* mutex() const _NOEXCEPT {return __m_;}
+};
+
+template <class _Mutex>
+void
+shared_lock<_Mutex>::lock()
+{
+    if (__m_ == nullptr)
+        __throw_system_error(EPERM, "shared_lock::lock: references null mutex");
+    if (__owns_)
+        __throw_system_error(EDEADLK, "shared_lock::lock: already locked");
+    __m_->lock_shared();
+    __owns_ = true;
+}
+
+template <class _Mutex>
+bool
+shared_lock<_Mutex>::try_lock()
+{
+    if (__m_ == nullptr)
+        __throw_system_error(EPERM, "shared_lock::try_lock: references null mutex");
+    if (__owns_)
+        __throw_system_error(EDEADLK, "shared_lock::try_lock: already locked");
+    __owns_ = __m_->try_lock_shared();
+    return __owns_;
+}
+
+template <class _Mutex>
+template <class _Rep, class _Period>
+bool
+shared_lock<_Mutex>::try_lock_for(const chrono::duration<_Rep, _Period>& __d)
+{
+    if (__m_ == nullptr)
+        __throw_system_error(EPERM, "shared_lock::try_lock_for: references null mutex");
+    if (__owns_)
+        __throw_system_error(EDEADLK, "shared_lock::try_lock_for: already locked");
+    __owns_ = __m_->try_lock_shared_for(__d);
+    return __owns_;
+}
+
+template <class _Mutex>
+template <class _Clock, class _Duration>
+bool
+shared_lock<_Mutex>::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
+{
+    if (__m_ == nullptr)
+        __throw_system_error(EPERM, "shared_lock::try_lock_until: references null mutex");
+    if (__owns_)
+        __throw_system_error(EDEADLK, "shared_lock::try_lock_until: already locked");
+    __owns_ = __m_->try_lock_shared_until(__t);
+    return __owns_;
+}
+
+template <class _Mutex>
+void
+shared_lock<_Mutex>::unlock()
+{
+    if (!__owns_)
+        __throw_system_error(EPERM, "shared_lock::unlock: not locked");
+    __m_->unlock_shared();
+    __owns_ = false;
+}
+
+template <class _Mutex>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(shared_lock<_Mutex>& __x, shared_lock<_Mutex>& __y) _NOEXCEPT
+    {__x.swap(__y);}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !_LIBCPP_HAS_NO_THREADS
+
+#endif // _LIBCPP_STD_VER > 11
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_SHARED_MUTEX
diff --git a/contrib/libs/cxxsupp/libcxx/include/span b/contrib/libs/cxxsupp/libcxx/include/span
new file mode 100644
index 00000000000..5d57bd693c5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/span
@@ -0,0 +1,658 @@
+// -*- C++ -*-
+//===------------------------------ span ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===---------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SPAN
+#define _LIBCPP_SPAN
+
+/*
+    span synopsis
+
+namespace std {
+
+// constants
+inline constexpr size_t dynamic_extent = numeric_limits<size_t>::max();
+
+// [views.span], class template span
+template <class ElementType, size_t Extent = dynamic_extent>
+    class span;
+
+template<class ElementType, size_t Extent>
+  inline constexpr bool ranges::enable_view<span<ElementType, Extent>> = true;
+
+template<class ElementType, size_t Extent>
+    inline constexpr bool ranges::enable_borrowed_range<span<ElementType, Extent>> = true;
+
+// [span.objectrep], views of object representation
+template <class ElementType, size_t Extent>
+    span<const byte, ((Extent == dynamic_extent) ? dynamic_extent :
+        (sizeof(ElementType) * Extent))> as_bytes(span<ElementType, Extent> s) noexcept;
+
+template <class ElementType, size_t Extent>
+    span<      byte, ((Extent == dynamic_extent) ? dynamic_extent :
+        (sizeof(ElementType) * Extent))> as_writable_bytes(span<ElementType, Extent> s) noexcept;
+
+
+template <class ElementType, size_t Extent = dynamic_extent>
+class span {
+public:
+    // constants and types
+    using element_type = ElementType;
+    using value_type = remove_cv_t<ElementType>;
+    using size_type = size_t;
+    using difference_type = ptrdiff_t;
+    using pointer = element_type*;
+    using const_pointer = const element_type*;
+    using reference = element_type&;
+    using const_reference = const element_type&;
+    using iterator = implementation-defined;
+    using reverse_iterator = std::reverse_iterator<iterator>;
+    static constexpr size_type extent = Extent;
+
+    // [span.cons], span constructors, copy, assignment, and destructor
+    constexpr span() noexcept;
+    template <class It>
+    constexpr explicit(Extent != dynamic_extent) span(It first, size_type count);
+    template <class It, class End>
+    constexpr explicit(Extent != dynamic_extent) span(It first, End last);
+    template <size_t N>
+        constexpr span(element_type (&arr)[N]) noexcept;
+    template <size_t N>
+        constexpr span(array<value_type, N>& arr) noexcept;
+    template <size_t N>
+        constexpr span(const array<value_type, N>& arr) noexcept;
+    template<class R>
+      constexpr explicit(Extent != dynamic_extent) span(R&& r);
+    constexpr span(const span& other) noexcept = default;
+    template <class OtherElementType, size_t OtherExtent>
+        constexpr explicit(Extent != dynamic_extent) span(const span<OtherElementType, OtherExtent>& s) noexcept;
+    ~span() noexcept = default;
+    constexpr span& operator=(const span& other) noexcept = default;
+
+    // [span.sub], span subviews
+    template <size_t Count>
+        constexpr span<element_type, Count> first() const;
+    template <size_t Count>
+        constexpr span<element_type, Count> last() const;
+    template <size_t Offset, size_t Count = dynamic_extent>
+        constexpr span<element_type, see below> subspan() const;
+
+    constexpr span<element_type, dynamic_extent> first(size_type count) const;
+    constexpr span<element_type, dynamic_extent> last(size_type count) const;
+    constexpr span<element_type, dynamic_extent> subspan(size_type offset, size_type count = dynamic_extent) const;
+
+    // [span.obs], span observers
+    constexpr size_type size() const noexcept;
+    constexpr size_type size_bytes() const noexcept;
+    constexpr bool empty() const noexcept;
+
+    // [span.elem], span element access
+    constexpr reference operator[](size_type idx) const;
+    constexpr reference front() const;
+    constexpr reference back() const;
+    constexpr pointer data() const noexcept;
+
+    // [span.iterators], span iterator support
+    constexpr iterator begin() const noexcept;
+    constexpr iterator end() const noexcept;
+    constexpr reverse_iterator rbegin() const noexcept;
+    constexpr reverse_iterator rend() const noexcept;
+
+private:
+    pointer data_;    // exposition only
+    size_type size_;  // exposition only
+};
+
+template<class It, class EndOrSize>
+    span(It, EndOrSize) -> span<remove_reference_t<iter_reference_t<_It>>>;
+
+template<class T, size_t N>
+    span(T (&)[N]) -> span<T, N>;
+
+template<class T, size_t N>
+    span(array<T, N>&) -> span<T, N>;
+
+template<class T, size_t N>
+    span(const array<T, N>&) -> span<const T, N>;
+
+template<class R>
+    span(R&&) -> span<remove_reference_t<ranges::range_reference_t<R>>>;
+
+} // namespace std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__iterator/concepts.h>
+#include <__iterator/wrap_iter.h>
+#include <__ranges/concepts.h>
+#include <__ranges/data.h>
+#include <__ranges/enable_borrowed_range.h>
+#include <__ranges/enable_view.h>
+#include <__ranges/size.h>
+#include <array>        // for array
+#include <cstddef>      // for byte
+#include <iterator>     // for iterators
+#include <limits>
+#include <type_traits>  // for remove_cv, etc
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+inline constexpr size_t dynamic_extent = numeric_limits<size_t>::max();
+template <typename _Tp, size_t _Extent = dynamic_extent> class span;
+
+
+template <class _Tp>
+struct __is_std_array : false_type {};
+
+template <class _Tp, size_t _Sz>
+struct __is_std_array<array<_Tp, _Sz>> : true_type {};
+
+template <class _Tp>
+struct __is_std_span : false_type {};
+
+template <class _Tp, size_t _Sz>
+struct __is_std_span<span<_Tp, _Sz>> : true_type {};
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+template <class _Range, class _ElementType>
+concept __span_compatible_range =
+  ranges::contiguous_range<_Range> &&
+  ranges::sized_range<_Range> &&
+  (ranges::borrowed_range<_Range> || is_const_v<_ElementType>) &&
+  !__is_std_span<remove_cvref_t<_Range>>::value  &&
+  !__is_std_array<remove_cvref_t<_Range>>::value &&
+  !is_array_v<remove_cvref_t<_Range>> &&
+  is_convertible_v<remove_reference_t<ranges::range_reference_t<_Range>>(*)[], _ElementType(*)[]>;
+#else
+template <class _Tp, class _ElementType, class = void>
+struct __is_span_compatible_container : public false_type {};
+
+template <class _Tp, class _ElementType>
+struct __is_span_compatible_container<_Tp, _ElementType,
+        void_t<
+        // is not a specialization of span
+            enable_if_t<!__is_std_span<_Tp>::value, nullptr_t>,
+        // is not a specialization of array
+            enable_if_t<!__is_std_array<_Tp>::value, nullptr_t>,
+        // is_array_v<Container> is false,
+            enable_if_t<!is_array_v<_Tp>, nullptr_t>,
+        // data(cont) and size(cont) are well formed
+            decltype(data(declval<_Tp>())),
+            decltype(size(declval<_Tp>())),
+        // remove_pointer_t<decltype(data(cont))>(*)[] is convertible to ElementType(*)[]
+            enable_if_t<
+                is_convertible_v<remove_pointer_t<decltype(data(declval<_Tp &>()))>(*)[],
+                                 _ElementType(*)[]>,
+                nullptr_t>
+        >>
+    : public true_type {};
+#endif
+
+template <typename _Tp, size_t _Extent>
+class _LIBCPP_TEMPLATE_VIS span {
+public:
+//  constants and types
+    using element_type           = _Tp;
+    using value_type             = remove_cv_t<_Tp>;
+    using size_type              = size_t;
+    using difference_type        = ptrdiff_t;
+    using pointer                = _Tp *;
+    using const_pointer          = const _Tp *;
+    using reference              = _Tp &;
+    using const_reference        = const _Tp &;
+#if (_LIBCPP_DEBUG_LEVEL == 2) || defined(_LIBCPP_ABI_SPAN_POINTER_ITERATORS)
+    using iterator               = pointer;
+#else
+    using iterator               = __wrap_iter<pointer>;
+#endif
+    using reverse_iterator       = _VSTD::reverse_iterator<iterator>;
+
+    static constexpr size_type extent = _Extent;
+
+// [span.cons], span constructors, copy, assignment, and destructor
+    template <size_t _Sz = _Extent, enable_if_t<_Sz == 0, nullptr_t> = nullptr>
+    _LIBCPP_INLINE_VISIBILITY constexpr span() noexcept : __data{nullptr} {}
+
+    constexpr span           (const span&) noexcept = default;
+    constexpr span& operator=(const span&) noexcept = default;
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+    template <class _It,
+              enable_if_t<contiguous_iterator<_It> &&
+                              is_convertible_v<remove_reference_t<iter_reference_t<_It>>(*)[], element_type (*)[]>,
+                          nullptr_t> = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit span(_It __first, size_type __count)
+        : __data{_VSTD::to_address(__first)} {
+      (void)__count;
+      _LIBCPP_ASSERT(_Extent == __count, "size mismatch in span's constructor (iterator, len)");
+    }
+
+    template <
+        class _It, class _End,
+        enable_if_t<is_convertible_v<remove_reference_t<iter_reference_t<_It> > (*)[], element_type (*)[]> &&
+                        contiguous_iterator<_It> && sized_sentinel_for<_End, _It> && !is_convertible_v<_End, size_t>,
+                    nullptr_t> = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit span(_It __first, _End __last) : __data{_VSTD::to_address(__first)} {
+      (void)__last;
+      _LIBCPP_ASSERT((__last - __first >= 0), "invalid range in span's constructor (iterator, sentinel)");
+      _LIBCPP_ASSERT(__last - __first == _Extent,
+                     "invalid range in span's constructor (iterator, sentinel): last - first != extent");
+    }
+#else
+    _LIBCPP_INLINE_VISIBILITY constexpr explicit span(pointer __ptr, size_type __count) : __data{__ptr}
+        { (void)__count; _LIBCPP_ASSERT(_Extent == __count, "size mismatch in span's constructor (ptr, len)"); }
+    _LIBCPP_INLINE_VISIBILITY constexpr explicit span(pointer __f, pointer __l) : __data{__f}
+        { (void)__l;     _LIBCPP_ASSERT(_Extent == distance(__f, __l), "size mismatch in span's constructor (ptr, ptr)"); }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY constexpr span(element_type (&__arr)[_Extent])          noexcept : __data{__arr} {}
+
+    template <class _OtherElementType,
+              enable_if_t<is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span(array<_OtherElementType, _Extent>& __arr) noexcept : __data{__arr.data()} {}
+
+    template <class _OtherElementType,
+              enable_if_t<is_convertible_v<const _OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span(const array<_OtherElementType, _Extent>& __arr) noexcept : __data{__arr.data()} {}
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+    template <__span_compatible_range<element_type> _Range>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr explicit span(_Range&& __r) : __data{ranges::data(__r)} {
+      _LIBCPP_ASSERT(ranges::size(__r) == _Extent, "size mismatch in span's constructor (range)");
+    }
+#else
+    template <class _Container>
+    _LIBCPP_INLINE_VISIBILITY
+        constexpr explicit span(      _Container& __c,
+            enable_if_t<__is_span_compatible_container<_Container, _Tp>::value, nullptr_t> = nullptr)
+        : __data{_VSTD::data(__c)} {
+            _LIBCPP_ASSERT(_Extent == _VSTD::size(__c), "size mismatch in span's constructor (range)");
+        }
+
+    template <class _Container>
+    _LIBCPP_INLINE_VISIBILITY
+        constexpr explicit span(const _Container& __c,
+            enable_if_t<__is_span_compatible_container<const _Container, _Tp>::value, nullptr_t> = nullptr)
+        : __data{_VSTD::data(__c)} {
+            _LIBCPP_ASSERT(_Extent == _VSTD::size(__c), "size mismatch in span's constructor (range)");
+        }
+#endif
+
+    template <class _OtherElementType>
+    _LIBCPP_INLINE_VISIBILITY
+        constexpr span(const span<_OtherElementType, _Extent>& __other,
+                       enable_if_t<
+                          is_convertible_v<_OtherElementType(*)[], element_type (*)[]>,
+                          nullptr_t> = nullptr)
+        : __data{__other.data()} {}
+
+    template <class _OtherElementType>
+    _LIBCPP_INLINE_VISIBILITY
+        constexpr explicit span(const span<_OtherElementType, dynamic_extent>& __other,
+                       enable_if_t<
+                          is_convertible_v<_OtherElementType(*)[], element_type (*)[]>,
+                          nullptr_t> = nullptr) noexcept
+        : __data{__other.data()} { _LIBCPP_ASSERT(_Extent == __other.size(), "size mismatch in span's constructor (other span)"); }
+
+
+//  ~span() noexcept = default;
+
+    template <size_t _Count>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span<element_type, _Count> first() const noexcept
+    {
+        static_assert(_Count <= _Extent, "Count out of range in span::first()");
+        return span<element_type, _Count>{data(), _Count};
+    }
+
+    template <size_t _Count>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span<element_type, _Count> last() const noexcept
+    {
+        static_assert(_Count <= _Extent, "Count out of range in span::last()");
+        return span<element_type, _Count>{data() + size() - _Count, _Count};
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span<element_type, dynamic_extent> first(size_type __count) const noexcept
+    {
+        _LIBCPP_ASSERT(__count <= size(), "Count out of range in span::first(count)");
+        return {data(), __count};
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span<element_type, dynamic_extent> last(size_type __count) const noexcept
+    {
+        _LIBCPP_ASSERT(__count <= size(), "Count out of range in span::last(count)");
+        return {data() + size() - __count, __count};
+    }
+
+    template <size_t _Offset, size_t _Count = dynamic_extent>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr auto subspan() const noexcept
+        -> span<element_type, _Count != dynamic_extent ? _Count : _Extent - _Offset>
+    {
+        static_assert(_Offset <= _Extent, "Offset out of range in span::subspan()");
+        static_assert(_Count == dynamic_extent || _Count <= _Extent - _Offset, "Offset + count out of range in span::subspan()");
+
+        using _ReturnType = span<element_type, _Count != dynamic_extent ? _Count : _Extent - _Offset>;
+        return _ReturnType{data() + _Offset, _Count == dynamic_extent ? size() - _Offset : _Count};
+    }
+
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span<element_type, dynamic_extent>
+       subspan(size_type __offset, size_type __count = dynamic_extent) const noexcept
+    {
+        _LIBCPP_ASSERT(__offset <= size(), "Offset out of range in span::subspan(offset, count)");
+        _LIBCPP_ASSERT(__count  <= size() || __count == dynamic_extent, "Count out of range in span::subspan(offset, count)");
+        if (__count == dynamic_extent)
+            return {data() + __offset, size() - __offset};
+        _LIBCPP_ASSERT(__count <= size() - __offset, "Offset + count out of range in span::subspan(offset, count)");
+        return {data() + __offset, __count};
+    }
+
+    _LIBCPP_INLINE_VISIBILITY constexpr size_type size()       const noexcept { return _Extent; }
+    _LIBCPP_INLINE_VISIBILITY constexpr size_type size_bytes() const noexcept { return _Extent * sizeof(element_type); }
+    _LIBCPP_INLINE_VISIBILITY constexpr bool empty()           const noexcept { return _Extent == 0; }
+
+    _LIBCPP_INLINE_VISIBILITY constexpr reference operator[](size_type __idx) const noexcept
+    {
+        _LIBCPP_ASSERT(__idx < size(), "span<T,N>[] index out of bounds");
+        return __data[__idx];
+    }
+
+    _LIBCPP_INLINE_VISIBILITY constexpr reference front() const noexcept
+    {
+        _LIBCPP_ASSERT(!empty(), "span<T, N>::front() on empty span");
+        return __data[0];
+    }
+
+    _LIBCPP_INLINE_VISIBILITY constexpr reference back() const noexcept
+    {
+        _LIBCPP_ASSERT(!empty(), "span<T, N>::back() on empty span");
+        return __data[size()-1];
+    }
+
+    _LIBCPP_INLINE_VISIBILITY constexpr pointer data()                         const noexcept { return __data; }
+
+// [span.iter], span iterator support
+    _LIBCPP_INLINE_VISIBILITY constexpr iterator                 begin() const noexcept { return iterator(data()); }
+    _LIBCPP_INLINE_VISIBILITY constexpr iterator                   end() const noexcept { return iterator(data() + size()); }
+    _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator        rbegin() const noexcept { return reverse_iterator(end()); }
+    _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator          rend() const noexcept { return reverse_iterator(begin()); }
+
+    _LIBCPP_INLINE_VISIBILITY span<const byte, _Extent * sizeof(element_type)> __as_bytes() const noexcept
+    { return span<const byte, _Extent * sizeof(element_type)>{reinterpret_cast<const byte *>(data()), size_bytes()}; }
+
+    _LIBCPP_INLINE_VISIBILITY span<byte, _Extent * sizeof(element_type)> __as_writable_bytes() const noexcept
+    { return span<byte, _Extent * sizeof(element_type)>{reinterpret_cast<byte *>(data()), size_bytes()}; }
+
+private:
+    pointer    __data;
+
+};
+
+
+template <typename _Tp>
+class _LIBCPP_TEMPLATE_VIS span<_Tp, dynamic_extent> {
+private:
+
+public:
+//  constants and types
+    using element_type           = _Tp;
+    using value_type             = remove_cv_t<_Tp>;
+    using size_type              = size_t;
+    using difference_type        = ptrdiff_t;
+    using pointer                = _Tp *;
+    using const_pointer          = const _Tp *;
+    using reference              = _Tp &;
+    using const_reference        = const _Tp &;
+#if (_LIBCPP_DEBUG_LEVEL == 2) || defined(_LIBCPP_ABI_SPAN_POINTER_ITERATORS)
+    using iterator               = pointer;
+#else
+    using iterator               = __wrap_iter<pointer>;
+#endif
+    using reverse_iterator       = _VSTD::reverse_iterator<iterator>;
+
+    static constexpr size_type extent = dynamic_extent;
+
+// [span.cons], span constructors, copy, assignment, and destructor
+    _LIBCPP_INLINE_VISIBILITY constexpr span() noexcept : __data{nullptr}, __size{0} {}
+
+    constexpr span           (const span&) noexcept = default;
+    constexpr span& operator=(const span&) noexcept = default;
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+    template <class _It,
+              enable_if_t<contiguous_iterator<_It> &&
+                              is_convertible_v<remove_reference_t<iter_reference_t<_It> > (*)[], element_type (*)[]>,
+                          nullptr_t> = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span(_It __first, size_type __count)
+        : __data{_VSTD::to_address(__first)}, __size{__count} {}
+
+    template <
+        class _It, class _End,
+        enable_if_t<is_convertible_v<remove_reference_t<iter_reference_t<_It> > (*)[], element_type (*)[]> &&
+                        contiguous_iterator<_It> && sized_sentinel_for<_End, _It> && !is_convertible_v<_End, size_t>,
+                    nullptr_t> = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span(_It __first, _End __last)
+        : __data(_VSTD::to_address(__first)), __size(__last - __first) {}
+#else
+    _LIBCPP_INLINE_VISIBILITY constexpr span(pointer __ptr, size_type __count) : __data{__ptr}, __size{__count} {}
+    _LIBCPP_INLINE_VISIBILITY constexpr span(pointer __f, pointer __l) : __data{__f}, __size{static_cast<size_t>(distance(__f, __l))} {}
+#endif
+
+    template <size_t _Sz>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span(element_type (&__arr)[_Sz])          noexcept : __data{__arr}, __size{_Sz} {}
+
+    template <class _OtherElementType, size_t _Sz,
+              enable_if_t<is_convertible_v<_OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span(array<_OtherElementType, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {}
+
+    template <class _OtherElementType, size_t _Sz,
+              enable_if_t<is_convertible_v<const _OtherElementType(*)[], element_type (*)[]>, nullptr_t> = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span(const array<_OtherElementType, _Sz>& __arr) noexcept : __data{__arr.data()}, __size{_Sz} {}
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+    template <__span_compatible_range<element_type> _Range>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span(_Range&& __r) : __data(ranges::data(__r)), __size{ranges::size(__r)} {}
+#else
+    template <class _Container>
+    _LIBCPP_INLINE_VISIBILITY
+        constexpr span(      _Container& __c,
+            enable_if_t<__is_span_compatible_container<_Container, _Tp>::value, nullptr_t> = nullptr)
+        : __data{_VSTD::data(__c)}, __size{(size_type) _VSTD::size(__c)} {}
+
+    template <class _Container>
+    _LIBCPP_INLINE_VISIBILITY
+        constexpr span(const _Container& __c,
+            enable_if_t<__is_span_compatible_container<const _Container, _Tp>::value, nullptr_t> = nullptr)
+        : __data{_VSTD::data(__c)}, __size{(size_type) _VSTD::size(__c)} {}
+#  endif
+
+    template <class _OtherElementType, size_t _OtherExtent>
+    _LIBCPP_INLINE_VISIBILITY
+        constexpr span(const span<_OtherElementType, _OtherExtent>& __other,
+                       enable_if_t<
+                          is_convertible_v<_OtherElementType(*)[], element_type (*)[]>,
+                          nullptr_t> = nullptr) noexcept
+        : __data{__other.data()}, __size{__other.size()} {}
+
+//    ~span() noexcept = default;
+
+    template <size_t _Count>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span<element_type, _Count> first() const noexcept
+    {
+        _LIBCPP_ASSERT(_Count <= size(), "Count out of range in span::first()");
+        return span<element_type, _Count>{data(), _Count};
+    }
+
+    template <size_t _Count>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span<element_type, _Count> last() const noexcept
+    {
+        _LIBCPP_ASSERT(_Count <= size(), "Count out of range in span::last()");
+        return span<element_type, _Count>{data() + size() - _Count, _Count};
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span<element_type, dynamic_extent> first(size_type __count) const noexcept
+    {
+        _LIBCPP_ASSERT(__count <= size(), "Count out of range in span::first(count)");
+        return {data(), __count};
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span<element_type, dynamic_extent> last (size_type __count) const noexcept
+    {
+        _LIBCPP_ASSERT(__count <= size(), "Count out of range in span::last(count)");
+        return {data() + size() - __count, __count};
+    }
+
+    template <size_t _Offset, size_t _Count = dynamic_extent>
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr span<element_type, _Count> subspan() const noexcept
+    {
+        _LIBCPP_ASSERT(_Offset <= size(), "Offset out of range in span::subspan()");
+        _LIBCPP_ASSERT(_Count == dynamic_extent || _Count <= size() - _Offset, "Offset + count out of range in span::subspan()");
+        return span<element_type, _Count>{data() + _Offset, _Count == dynamic_extent ? size() - _Offset : _Count};
+    }
+
+    constexpr span<element_type, dynamic_extent>
+    _LIBCPP_INLINE_VISIBILITY
+    subspan(size_type __offset, size_type __count = dynamic_extent) const noexcept
+    {
+        _LIBCPP_ASSERT(__offset <= size(), "Offset out of range in span::subspan(offset, count)");
+        _LIBCPP_ASSERT(__count  <= size() || __count == dynamic_extent, "count out of range in span::subspan(offset, count)");
+        if (__count == dynamic_extent)
+            return {data() + __offset, size() - __offset};
+        _LIBCPP_ASSERT(__count <= size() - __offset, "Offset + count out of range in span::subspan(offset, count)");
+        return {data() + __offset, __count};
+    }
+
+    _LIBCPP_INLINE_VISIBILITY constexpr size_type size()       const noexcept { return __size; }
+    _LIBCPP_INLINE_VISIBILITY constexpr size_type size_bytes() const noexcept { return __size * sizeof(element_type); }
+    _LIBCPP_INLINE_VISIBILITY constexpr bool empty()           const noexcept { return __size == 0; }
+
+    _LIBCPP_INLINE_VISIBILITY constexpr reference operator[](size_type __idx) const noexcept
+    {
+        _LIBCPP_ASSERT(__idx < size(), "span<T>[] index out of bounds");
+        return __data[__idx];
+    }
+
+    _LIBCPP_INLINE_VISIBILITY constexpr reference front() const noexcept
+    {
+        _LIBCPP_ASSERT(!empty(), "span<T>[].front() on empty span");
+        return __data[0];
+    }
+
+    _LIBCPP_INLINE_VISIBILITY constexpr reference back() const noexcept
+    {
+        _LIBCPP_ASSERT(!empty(), "span<T>[].back() on empty span");
+        return __data[size()-1];
+    }
+
+
+    _LIBCPP_INLINE_VISIBILITY constexpr pointer data()                         const noexcept { return __data; }
+
+// [span.iter], span iterator support
+    _LIBCPP_INLINE_VISIBILITY constexpr iterator                 begin() const noexcept { return iterator(data()); }
+    _LIBCPP_INLINE_VISIBILITY constexpr iterator                   end() const noexcept { return iterator(data() + size()); }
+    _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator        rbegin() const noexcept { return reverse_iterator(end()); }
+    _LIBCPP_INLINE_VISIBILITY constexpr reverse_iterator          rend() const noexcept { return reverse_iterator(begin()); }
+
+    inline _LIBCPP_INLINE_VISIBILITY span<const byte, dynamic_extent> __as_bytes() const noexcept;
+
+    inline _LIBCPP_INLINE_VISIBILITY span<byte, dynamic_extent> __as_writable_bytes() const noexcept;
+
+private:
+    pointer   __data;
+    size_type __size;
+};
+
+template<typename _Tp>
+inline _LIBCPP_INLINE_VISIBILITY span<const byte, dynamic_extent> span<_Tp, dynamic_extent>::__as_bytes() const noexcept
+{ return {reinterpret_cast<const byte *>(data()), size_bytes()}; }
+
+template<typename _Tp>
+inline _LIBCPP_INLINE_VISIBILITY span<byte, dynamic_extent> span<_Tp, dynamic_extent>::__as_writable_bytes() const noexcept
+{ return {reinterpret_cast<byte *>(data()), size_bytes()}; }
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+template <class _Tp, size_t _Extent>
+inline constexpr bool ranges::enable_borrowed_range<span<_Tp, _Extent> > = true;
+
+template <class _ElementType, size_t _Extent>
+inline constexpr bool ranges::enable_view<span<_ElementType, _Extent>> = true;
+#endif // !defined(_LIBCPP_HAS_NO_RANGES)
+
+//  as_bytes & as_writable_bytes
+template <class _Tp, size_t _Extent>
+_LIBCPP_INLINE_VISIBILITY
+auto as_bytes(span<_Tp, _Extent> __s) noexcept
+-> decltype(__s.__as_bytes())
+{ return    __s.__as_bytes(); }
+
+template <class _Tp, size_t _Extent>
+_LIBCPP_INLINE_VISIBILITY
+auto as_writable_bytes(span<_Tp, _Extent> __s) noexcept
+-> enable_if_t<!is_const_v<_Tp>, decltype(__s.__as_writable_bytes())>
+{ return __s.__as_writable_bytes(); }
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+//  Deduction guides
+template<contiguous_iterator _It, class _EndOrSize>
+    span(_It, _EndOrSize) -> span<remove_reference_t<iter_reference_t<_It>>>;
+#endif
+
+template<class _Tp, size_t _Sz>
+    span(_Tp (&)[_Sz]) -> span<_Tp, _Sz>;
+
+template<class _Tp, size_t _Sz>
+    span(array<_Tp, _Sz>&) -> span<_Tp, _Sz>;
+
+template<class _Tp, size_t _Sz>
+    span(const array<_Tp, _Sz>&) -> span<const _Tp, _Sz>;
+
+#if !defined(_LIBCPP_HAS_NO_RANGES)
+template<ranges::contiguous_range _Range>
+    span(_Range&&) -> span<remove_reference_t<ranges::range_reference_t<_Range>>>;
+#endif
+
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_SPAN
diff --git a/contrib/libs/cxxsupp/libcxx/include/sstream b/contrib/libs/cxxsupp/libcxx/include/sstream
new file mode 100644
index 00000000000..fbe5ffcab4c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/sstream
@@ -0,0 +1,871 @@
+// -*- C++ -*-
+//===--------------------------- sstream ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SSTREAM
+#define _LIBCPP_SSTREAM
+
+/*
+    sstream synopsis
+
+template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+class basic_stringbuf
+    : public basic_streambuf<charT, traits>
+{
+public:
+    typedef charT                          char_type;
+    typedef traits                         traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+    typedef Allocator                      allocator_type;
+
+    // 27.8.1.1 [stringbuf.cons], constructors:
+    explicit basic_stringbuf(ios_base::openmode which = ios_base::in | ios_base::out); // before C++20
+    basic_stringbuf() : basic_stringbuf(ios_base::in | ios_base::out) {}               // C++20
+    explicit basic_stringbuf(ios_base::openmode which);                                // C++20
+    explicit basic_stringbuf(const basic_string<char_type, traits_type, allocator_type>& str,
+                             ios_base::openmode which = ios_base::in | ios_base::out);
+    basic_stringbuf(basic_stringbuf&& rhs);
+
+    // 27.8.1.2 Assign and swap:
+    basic_stringbuf& operator=(basic_stringbuf&& rhs);
+    void swap(basic_stringbuf& rhs);
+
+    // 27.8.1.3 Get and set:
+    basic_string<char_type, traits_type, allocator_type> str() const;
+    void str(const basic_string<char_type, traits_type, allocator_type>& s);
+
+protected:
+    // 27.8.1.4 Overridden virtual functions:
+    virtual int_type underflow();
+    virtual int_type pbackfail(int_type c = traits_type::eof());
+    virtual int_type overflow (int_type c = traits_type::eof());
+    virtual basic_streambuf<char_type, traits_type>* setbuf(char_type*, streamsize);
+    virtual pos_type seekoff(off_type off, ios_base::seekdir way,
+                             ios_base::openmode which = ios_base::in | ios_base::out);
+    virtual pos_type seekpos(pos_type sp,
+                             ios_base::openmode which = ios_base::in | ios_base::out);
+};
+
+template <class charT, class traits, class Allocator>
+  void swap(basic_stringbuf<charT, traits, Allocator>& x,
+            basic_stringbuf<charT, traits, Allocator>& y);
+
+typedef basic_stringbuf<char>    stringbuf;
+typedef basic_stringbuf<wchar_t> wstringbuf;
+
+template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+class basic_istringstream
+    : public basic_istream<charT, traits>
+{
+public:
+    typedef charT                          char_type;
+    typedef traits                         traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+    typedef Allocator                      allocator_type;
+
+    // 27.8.2.1 Constructors:
+    explicit basic_istringstream(ios_base::openmode which = ios_base::in); // before C++20
+    basic_istringstream() : basic_istringstream(ios_base::in) {}           // C++20
+    explicit basic_istringstream(ios_base::openmode which);                // C++20
+
+    explicit basic_istringstream(const basic_string<char_type, traits_type,allocator_type>& str,
+                                 ios_base::openmode which = ios_base::in);
+    basic_istringstream(basic_istringstream&& rhs);
+
+    // 27.8.2.2 Assign and swap:
+    basic_istringstream& operator=(basic_istringstream&& rhs);
+    void swap(basic_istringstream& rhs);
+
+    // 27.8.2.3 Members:
+    basic_stringbuf<char_type, traits_type, allocator_type>* rdbuf() const;
+    basic_string<char_type, traits_type, allocator_type> str() const;
+    void str(const basic_string<char_type, traits_type, allocator_type>& s);
+};
+
+template <class charT, class traits, class Allocator>
+  void swap(basic_istringstream<charT, traits, Allocator>& x,
+            basic_istringstream<charT, traits, Allocator>& y);
+
+typedef basic_istringstream<char>    istringstream;
+typedef basic_istringstream<wchar_t> wistringstream;
+
+template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+class basic_ostringstream
+    : public basic_ostream<charT, traits>
+{
+public:
+    // types:
+    typedef charT                          char_type;
+    typedef traits                         traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+    typedef Allocator                      allocator_type;
+
+    // 27.8.3.1 Constructors/destructor:
+    explicit basic_ostringstream(ios_base::openmode which = ios_base::out); // before C++20
+    basic_ostringstream() : basic_ostringstream(ios_base::out) {}           // C++20
+    explicit basic_ostringstream(ios_base::openmode which);                 // C++20
+
+    explicit basic_ostringstream(const basic_string<char_type, traits_type, allocator_type>& str,
+                                 ios_base::openmode which = ios_base::out);
+    basic_ostringstream(basic_ostringstream&& rhs);
+
+    // 27.8.3.2 Assign/swap:
+    basic_ostringstream& operator=(basic_ostringstream&& rhs);
+    void swap(basic_ostringstream& rhs);
+
+    // 27.8.3.3 Members:
+    basic_stringbuf<char_type, traits_type, allocator_type>* rdbuf() const;
+    basic_string<char_type, traits_type, allocator_type> str() const;
+    void str(const basic_string<char_type, traits_type, allocator_type>& s);
+};
+
+template <class charT, class traits, class Allocator>
+  void swap(basic_ostringstream<charT, traits, Allocator>& x,
+            basic_ostringstream<charT, traits, Allocator>& y);
+
+typedef basic_ostringstream<char>    ostringstream;
+typedef basic_ostringstream<wchar_t> wostringstream;
+
+template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+class basic_stringstream
+    : public basic_iostream<charT, traits>
+{
+public:
+    // types:
+    typedef charT                          char_type;
+    typedef traits                         traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+    typedef Allocator                      allocator_type;
+
+    // constructors/destructor
+    explicit basic_stringstream(ios_base::openmode which = ios_base::out | ios_base::in); // before C++20
+    basic_stringstream() : basic_stringstream(ios_base::out | ios_base::in) {}            // C++20
+    explicit basic_stringstream(ios_base::openmode which);                                // C++20
+
+    explicit basic_stringstream(const basic_string<char_type, traits_type, allocator_type>& str,
+                                ios_base::openmode which = ios_base::out|ios_base::in);
+    basic_stringstream(basic_stringstream&& rhs);
+
+    // 27.8.5.1 Assign/swap:
+    basic_stringstream& operator=(basic_stringstream&& rhs);
+    void swap(basic_stringstream& rhs);
+
+    // Members:
+    basic_stringbuf<char_type, traits_type, allocator_type>* rdbuf() const;
+    basic_string<char_type, traits_type, allocator_type> str() const;
+    void str(const basic_string<char_type, traits_type, allocator_type>& str);
+};
+
+template <class charT, class traits, class Allocator>
+  void swap(basic_stringstream<charT, traits, Allocator>& x,
+            basic_stringstream<charT, traits, Allocator>& y);
+
+typedef basic_stringstream<char>    stringstream;
+typedef basic_stringstream<wchar_t> wstringstream;
+
+}  // std
+
+*/
+
+#include <__config>
+#include <istream>
+#include <ostream>
+#include <string>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// basic_stringbuf
+
+template <class _CharT, class _Traits, class _Allocator>
+class _LIBCPP_TEMPLATE_VIS basic_stringbuf
+    : public basic_streambuf<_CharT, _Traits>
+{
+public:
+    typedef _CharT                         char_type;
+    typedef _Traits                        traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+    typedef _Allocator                     allocator_type;
+
+    typedef basic_string<char_type, traits_type, allocator_type> string_type;
+
+private:
+
+    string_type __str_;
+    mutable char_type* __hm_;
+    ios_base::openmode __mode_;
+
+public:
+    // 30.8.2.1 [stringbuf.cons], constructors
+    _LIBCPP_INLINE_VISIBILITY
+    basic_stringbuf()
+        : __hm_(nullptr), __mode_(ios_base::in | ios_base::out) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_stringbuf(ios_base::openmode __wch)
+        : __hm_(nullptr), __mode_(__wch) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_stringbuf(const string_type& __s,
+                             ios_base::openmode __wch = ios_base::in | ios_base::out)
+        : __str_(__s.get_allocator()), __hm_(nullptr), __mode_(__wch)
+    {
+        str(__s);
+    }
+
+    basic_stringbuf(basic_stringbuf&& __rhs);
+
+    // 27.8.1.2 Assign and swap:
+    basic_stringbuf& operator=(basic_stringbuf&& __rhs);
+    void swap(basic_stringbuf& __rhs);
+
+    // 27.8.1.3 Get and set:
+    string_type str() const;
+    void str(const string_type& __s);
+
+protected:
+    // 27.8.1.4 Overridden virtual functions:
+    virtual int_type underflow();
+    virtual int_type pbackfail(int_type __c = traits_type::eof());
+    virtual int_type overflow (int_type __c = traits_type::eof());
+    virtual pos_type seekoff(off_type __off, ios_base::seekdir __way,
+                             ios_base::openmode __wch = ios_base::in | ios_base::out);
+    _LIBCPP_INLINE_VISIBILITY
+    virtual pos_type seekpos(pos_type __sp,
+                             ios_base::openmode __wch = ios_base::in | ios_base::out) {
+        return seekoff(__sp, ios_base::beg, __wch);
+    }
+};
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_stringbuf<_CharT, _Traits, _Allocator>::basic_stringbuf(basic_stringbuf&& __rhs)
+    : __mode_(__rhs.__mode_)
+{
+    char_type* __p = const_cast<char_type*>(__rhs.__str_.data());
+    ptrdiff_t __binp = -1;
+    ptrdiff_t __ninp = -1;
+    ptrdiff_t __einp = -1;
+    if (__rhs.eback() != nullptr)
+    {
+        __binp = __rhs.eback() - __p;
+        __ninp = __rhs.gptr() - __p;
+        __einp = __rhs.egptr() - __p;
+    }
+    ptrdiff_t __bout = -1;
+    ptrdiff_t __nout = -1;
+    ptrdiff_t __eout = -1;
+    if (__rhs.pbase() != nullptr)
+    {
+        __bout = __rhs.pbase() - __p;
+        __nout = __rhs.pptr() - __p;
+        __eout = __rhs.epptr() - __p;
+    }
+    ptrdiff_t __hm = __rhs.__hm_ == nullptr ? -1 : __rhs.__hm_ - __p;
+    __str_ = _VSTD::move(__rhs.__str_);
+    __p = const_cast<char_type*>(__str_.data());
+    if (__binp != -1)
+        this->setg(__p + __binp, __p + __ninp, __p + __einp);
+    if (__bout != -1)
+    {
+        this->setp(__p + __bout, __p + __eout);
+        this->__pbump(__nout);
+    }
+    __hm_ = __hm == -1 ? nullptr : __p + __hm;
+    __p = const_cast<char_type*>(__rhs.__str_.data());
+    __rhs.setg(__p, __p, __p);
+    __rhs.setp(__p, __p);
+    __rhs.__hm_ = __p;
+    this->pubimbue(__rhs.getloc());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_stringbuf<_CharT, _Traits, _Allocator>&
+basic_stringbuf<_CharT, _Traits, _Allocator>::operator=(basic_stringbuf&& __rhs)
+{
+    char_type* __p = const_cast<char_type*>(__rhs.__str_.data());
+    ptrdiff_t __binp = -1;
+    ptrdiff_t __ninp = -1;
+    ptrdiff_t __einp = -1;
+    if (__rhs.eback() != nullptr)
+    {
+        __binp = __rhs.eback() - __p;
+        __ninp = __rhs.gptr() - __p;
+        __einp = __rhs.egptr() - __p;
+    }
+    ptrdiff_t __bout = -1;
+    ptrdiff_t __nout = -1;
+    ptrdiff_t __eout = -1;
+    if (__rhs.pbase() != nullptr)
+    {
+        __bout = __rhs.pbase() - __p;
+        __nout = __rhs.pptr() - __p;
+        __eout = __rhs.epptr() - __p;
+    }
+    ptrdiff_t __hm = __rhs.__hm_ == nullptr ? -1 : __rhs.__hm_ - __p;
+    __str_ = _VSTD::move(__rhs.__str_);
+    __p = const_cast<char_type*>(__str_.data());
+    if (__binp != -1)
+        this->setg(__p + __binp, __p + __ninp, __p + __einp);
+    else
+        this->setg(nullptr, nullptr, nullptr);
+    if (__bout != -1)
+    {
+        this->setp(__p + __bout, __p + __eout);
+        this->__pbump(__nout);
+    }
+    else
+        this->setp(nullptr, nullptr);
+
+    __hm_ = __hm == -1 ? nullptr : __p + __hm;
+    __mode_ = __rhs.__mode_;
+    __p = const_cast<char_type*>(__rhs.__str_.data());
+    __rhs.setg(__p, __p, __p);
+    __rhs.setp(__p, __p);
+    __rhs.__hm_ = __p;
+    this->pubimbue(__rhs.getloc());
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+void
+basic_stringbuf<_CharT, _Traits, _Allocator>::swap(basic_stringbuf& __rhs)
+{
+    char_type* __p = const_cast<char_type*>(__rhs.__str_.data());
+    ptrdiff_t __rbinp = -1;
+    ptrdiff_t __rninp = -1;
+    ptrdiff_t __reinp = -1;
+    if (__rhs.eback() != nullptr)
+    {
+        __rbinp = __rhs.eback() - __p;
+        __rninp = __rhs.gptr() - __p;
+        __reinp = __rhs.egptr() - __p;
+    }
+    ptrdiff_t __rbout = -1;
+    ptrdiff_t __rnout = -1;
+    ptrdiff_t __reout = -1;
+    if (__rhs.pbase() != nullptr)
+    {
+        __rbout = __rhs.pbase() - __p;
+        __rnout = __rhs.pptr() - __p;
+        __reout = __rhs.epptr() - __p;
+    }
+    ptrdiff_t __rhm = __rhs.__hm_ == nullptr ? -1 : __rhs.__hm_ - __p;
+    __p = const_cast<char_type*>(__str_.data());
+    ptrdiff_t __lbinp = -1;
+    ptrdiff_t __lninp = -1;
+    ptrdiff_t __leinp = -1;
+    if (this->eback() != nullptr)
+    {
+        __lbinp = this->eback() - __p;
+        __lninp = this->gptr() - __p;
+        __leinp = this->egptr() - __p;
+    }
+    ptrdiff_t __lbout = -1;
+    ptrdiff_t __lnout = -1;
+    ptrdiff_t __leout = -1;
+    if (this->pbase() != nullptr)
+    {
+        __lbout = this->pbase() - __p;
+        __lnout = this->pptr() - __p;
+        __leout = this->epptr() - __p;
+    }
+    ptrdiff_t __lhm = __hm_ == nullptr ? -1 : __hm_ - __p;
+    _VSTD::swap(__mode_, __rhs.__mode_);
+    __str_.swap(__rhs.__str_);
+    __p = const_cast<char_type*>(__str_.data());
+    if (__rbinp != -1)
+        this->setg(__p + __rbinp, __p + __rninp, __p + __reinp);
+    else
+        this->setg(nullptr, nullptr, nullptr);
+    if (__rbout != -1)
+    {
+        this->setp(__p + __rbout, __p + __reout);
+        this->__pbump(__rnout);
+    }
+    else
+        this->setp(nullptr, nullptr);
+    __hm_ = __rhm == -1 ? nullptr : __p + __rhm;
+    __p = const_cast<char_type*>(__rhs.__str_.data());
+    if (__lbinp != -1)
+        __rhs.setg(__p + __lbinp, __p + __lninp, __p + __leinp);
+    else
+        __rhs.setg(nullptr, nullptr, nullptr);
+    if (__lbout != -1)
+    {
+        __rhs.setp(__p + __lbout, __p + __leout);
+        __rhs.__pbump(__lnout);
+    }
+    else
+        __rhs.setp(nullptr, nullptr);
+    __rhs.__hm_ = __lhm == -1 ? nullptr : __p + __lhm;
+    locale __tl = __rhs.getloc();
+    __rhs.pubimbue(this->getloc());
+    this->pubimbue(__tl);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(basic_stringbuf<_CharT, _Traits, _Allocator>& __x,
+     basic_stringbuf<_CharT, _Traits, _Allocator>& __y)
+{
+    __x.swap(__y);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>
+basic_stringbuf<_CharT, _Traits, _Allocator>::str() const
+{
+    if (__mode_ & ios_base::out)
+    {
+        if (__hm_ < this->pptr())
+            __hm_ = this->pptr();
+        return string_type(this->pbase(), __hm_, __str_.get_allocator());
+    }
+    else if (__mode_ & ios_base::in)
+        return string_type(this->eback(), this->egptr(), __str_.get_allocator());
+    return string_type(__str_.get_allocator());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+void
+basic_stringbuf<_CharT, _Traits, _Allocator>::str(const string_type& __s)
+{
+    __str_ = __s;
+    __hm_ = nullptr;
+    if (__mode_ & ios_base::in)
+    {
+        __hm_ = const_cast<char_type*>(__str_.data()) + __str_.size();
+        this->setg(const_cast<char_type*>(__str_.data()),
+                   const_cast<char_type*>(__str_.data()),
+                   __hm_);
+    }
+    if (__mode_ & ios_base::out)
+    {
+        typename string_type::size_type __sz = __str_.size();
+        __hm_ = const_cast<char_type*>(__str_.data()) + __sz;
+        __str_.resize(__str_.capacity());
+        this->setp(const_cast<char_type*>(__str_.data()),
+                   const_cast<char_type*>(__str_.data()) + __str_.size());
+        if (__mode_ & (ios_base::app | ios_base::ate))
+        {
+            while (__sz > INT_MAX)
+            {
+                this->pbump(INT_MAX);
+                __sz -= INT_MAX;
+            }
+            if (__sz > 0)
+                this->pbump(__sz);
+        }
+    }
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+typename basic_stringbuf<_CharT, _Traits, _Allocator>::int_type
+basic_stringbuf<_CharT, _Traits, _Allocator>::underflow()
+{
+    if (__hm_ < this->pptr())
+        __hm_ = this->pptr();
+    if (__mode_ & ios_base::in)
+    {
+        if (this->egptr() < __hm_)
+            this->setg(this->eback(), this->gptr(), __hm_);
+        if (this->gptr() < this->egptr())
+            return traits_type::to_int_type(*this->gptr());
+    }
+    return traits_type::eof();
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+typename basic_stringbuf<_CharT, _Traits, _Allocator>::int_type
+basic_stringbuf<_CharT, _Traits, _Allocator>::pbackfail(int_type __c)
+{
+    if (__hm_ < this->pptr())
+        __hm_ = this->pptr();
+    if (this->eback() < this->gptr())
+    {
+        if (traits_type::eq_int_type(__c, traits_type::eof()))
+        {
+            this->setg(this->eback(), this->gptr()-1, __hm_);
+            return traits_type::not_eof(__c);
+        }
+        if ((__mode_ & ios_base::out) ||
+            traits_type::eq(traits_type::to_char_type(__c), this->gptr()[-1]))
+        {
+            this->setg(this->eback(), this->gptr()-1, __hm_);
+            *this->gptr() = traits_type::to_char_type(__c);
+            return __c;
+        }
+    }
+    return traits_type::eof();
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+typename basic_stringbuf<_CharT, _Traits, _Allocator>::int_type
+basic_stringbuf<_CharT, _Traits, _Allocator>::overflow(int_type __c)
+{
+    if (!traits_type::eq_int_type(__c, traits_type::eof()))
+    {
+        ptrdiff_t __ninp = this->gptr()  - this->eback();
+        if (this->pptr() == this->epptr())
+        {
+            if (!(__mode_ & ios_base::out))
+                return traits_type::eof();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+            try
+            {
+#endif // _LIBCPP_NO_EXCEPTIONS
+                ptrdiff_t __nout = this->pptr()  - this->pbase();
+                ptrdiff_t __hm = __hm_ - this->pbase();
+                __str_.push_back(char_type());
+                __str_.resize(__str_.capacity());
+                char_type* __p = const_cast<char_type*>(__str_.data());
+                this->setp(__p, __p + __str_.size());
+                this->__pbump(__nout);
+                __hm_ = this->pbase() + __hm;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+            }
+            catch (...)
+            {
+                return traits_type::eof();
+            }
+#endif // _LIBCPP_NO_EXCEPTIONS
+        }
+        __hm_ = _VSTD::max(this->pptr() + 1, __hm_);
+        if (__mode_ & ios_base::in)
+        {
+            char_type* __p = const_cast<char_type*>(__str_.data());
+            this->setg(__p, __p + __ninp, __hm_);
+        }
+        return this->sputc(traits_type::to_char_type(__c));
+    }
+    return traits_type::not_eof(__c);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+typename basic_stringbuf<_CharT, _Traits, _Allocator>::pos_type
+basic_stringbuf<_CharT, _Traits, _Allocator>::seekoff(off_type __off,
+                                                      ios_base::seekdir __way,
+                                                      ios_base::openmode __wch)
+{
+    if (__hm_ < this->pptr())
+        __hm_ = this->pptr();
+    if ((__wch & (ios_base::in | ios_base::out)) == 0)
+        return pos_type(-1);
+    if ((__wch & (ios_base::in | ios_base::out)) == (ios_base::in | ios_base::out)
+        && __way == ios_base::cur)
+        return pos_type(-1);
+    const ptrdiff_t __hm = __hm_ == nullptr ? 0 : __hm_ - __str_.data();
+    off_type __noff;
+    switch (__way)
+    {
+    case ios_base::beg:
+        __noff = 0;
+        break;
+    case ios_base::cur:
+        if (__wch & ios_base::in)
+            __noff = this->gptr() - this->eback();
+        else
+            __noff = this->pptr() - this->pbase();
+        break;
+    case ios_base::end:
+        __noff = __hm;
+        break;
+    default:
+        return pos_type(-1);
+    }
+    __noff += __off;
+    if (__noff < 0 || __hm < __noff)
+        return pos_type(-1);
+    if (__noff != 0)
+    {
+        if ((__wch & ios_base::in) && this->gptr() == nullptr)
+            return pos_type(-1);
+        if ((__wch & ios_base::out) && this->pptr() == nullptr)
+            return pos_type(-1);
+    }
+    if (__wch & ios_base::in)
+        this->setg(this->eback(), this->eback() + __noff, __hm_);
+    if (__wch & ios_base::out)
+    {
+        this->setp(this->pbase(), this->epptr());
+        this->pbump(__noff);
+    }
+    return pos_type(__noff);
+}
+
+// basic_istringstream
+
+template <class _CharT, class _Traits, class _Allocator>
+class _LIBCPP_TEMPLATE_VIS basic_istringstream
+    : public basic_istream<_CharT, _Traits>
+{
+public:
+    typedef _CharT                         char_type;
+    typedef _Traits                        traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+    typedef _Allocator                     allocator_type;
+
+    typedef basic_string<char_type, traits_type, allocator_type> string_type;
+
+private:
+    basic_stringbuf<char_type, traits_type, allocator_type> __sb_;
+
+public:
+    // 30.8.3.1 [istringstream.cons], constructors
+    _LIBCPP_INLINE_VISIBILITY
+    basic_istringstream()
+        : basic_istream<_CharT, _Traits>(&__sb_), __sb_(ios_base::in) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_istringstream(ios_base::openmode __wch)
+        : basic_istream<_CharT, _Traits>(&__sb_), __sb_(__wch | ios_base::in) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_istringstream(const string_type& __s,
+                                 ios_base::openmode __wch = ios_base::in)
+        : basic_istream<_CharT, _Traits>(&__sb_)
+        , __sb_(__s, __wch | ios_base::in)
+    { }
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_istringstream(basic_istringstream&& __rhs)
+        : basic_istream<_CharT, _Traits>(_VSTD::move(__rhs))
+        , __sb_(_VSTD::move(__rhs.__sb_))
+    {
+        basic_istream<_CharT, _Traits>::set_rdbuf(&__sb_);
+    }
+
+    // 27.8.2.2 Assign and swap:
+    basic_istringstream& operator=(basic_istringstream&& __rhs) {
+        basic_istream<char_type, traits_type>::operator=(_VSTD::move(__rhs));
+        __sb_ = _VSTD::move(__rhs.__sb_);
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(basic_istringstream& __rhs) {
+        basic_istream<char_type, traits_type>::swap(__rhs);
+        __sb_.swap(__rhs.__sb_);
+    }
+
+    // 27.8.2.3 Members:
+    _LIBCPP_INLINE_VISIBILITY
+    basic_stringbuf<char_type, traits_type, allocator_type>* rdbuf() const {
+        return const_cast<basic_stringbuf<char_type, traits_type, allocator_type>*>(&__sb_);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    string_type str() const {
+        return __sb_.str();
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    void str(const string_type& __s) {
+        __sb_.str(__s);
+    }
+};
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(basic_istringstream<_CharT, _Traits, _Allocator>& __x,
+     basic_istringstream<_CharT, _Traits, _Allocator>& __y)
+{
+    __x.swap(__y);
+}
+
+// basic_ostringstream
+
+template <class _CharT, class _Traits, class _Allocator>
+class _LIBCPP_TEMPLATE_VIS basic_ostringstream
+    : public basic_ostream<_CharT, _Traits>
+{
+public:
+    typedef _CharT                         char_type;
+    typedef _Traits                        traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+    typedef _Allocator                     allocator_type;
+
+    typedef basic_string<char_type, traits_type, allocator_type> string_type;
+
+private:
+    basic_stringbuf<char_type, traits_type, allocator_type> __sb_;
+
+public:
+    // 30.8.4.1 [ostringstream.cons], constructors
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ostringstream()
+        : basic_ostream<_CharT, _Traits>(&__sb_), __sb_(ios_base::out) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_ostringstream(ios_base::openmode __wch)
+        : basic_ostream<_CharT, _Traits>(&__sb_), __sb_(__wch | ios_base::out) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_ostringstream(const string_type& __s,
+                                 ios_base::openmode __wch = ios_base::out)
+        : basic_ostream<_CharT, _Traits>(&__sb_)
+        , __sb_(__s, __wch | ios_base::out)
+    { }
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_ostringstream(basic_ostringstream&& __rhs)
+        : basic_ostream<_CharT, _Traits>(_VSTD::move(__rhs))
+        , __sb_(_VSTD::move(__rhs.__sb_))
+    {
+        basic_ostream<_CharT, _Traits>::set_rdbuf(&__sb_);
+    }
+
+    // 27.8.2.2 Assign and swap:
+    basic_ostringstream& operator=(basic_ostringstream&& __rhs) {
+        basic_ostream<char_type, traits_type>::operator=(_VSTD::move(__rhs));
+        __sb_ = _VSTD::move(__rhs.__sb_);
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(basic_ostringstream& __rhs) {
+        basic_ostream<char_type, traits_type>::swap(__rhs);
+        __sb_.swap(__rhs.__sb_);
+    }
+
+    // 27.8.2.3 Members:
+    _LIBCPP_INLINE_VISIBILITY
+    basic_stringbuf<char_type, traits_type, allocator_type>* rdbuf() const {
+        return const_cast<basic_stringbuf<char_type, traits_type, allocator_type>*>(&__sb_);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    string_type str() const {
+        return __sb_.str();
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    void str(const string_type& __s) {
+        __sb_.str(__s);
+    }
+};
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(basic_ostringstream<_CharT, _Traits, _Allocator>& __x,
+     basic_ostringstream<_CharT, _Traits, _Allocator>& __y)
+{
+    __x.swap(__y);
+}
+
+// basic_stringstream
+
+template <class _CharT, class _Traits, class _Allocator>
+class _LIBCPP_TEMPLATE_VIS basic_stringstream
+    : public basic_iostream<_CharT, _Traits>
+{
+public:
+    typedef _CharT                         char_type;
+    typedef _Traits                        traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+    typedef _Allocator                     allocator_type;
+
+    typedef basic_string<char_type, traits_type, allocator_type> string_type;
+
+private:
+    basic_stringbuf<char_type, traits_type, allocator_type> __sb_;
+
+public:
+    // 30.8.5.1 [stringstream.cons], constructors
+    _LIBCPP_INLINE_VISIBILITY
+    basic_stringstream()
+        : basic_iostream<_CharT, _Traits>(&__sb_), __sb_(ios_base::in | ios_base::out) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_stringstream(ios_base::openmode __wch)
+        : basic_iostream<_CharT, _Traits>(&__sb_), __sb_(__wch) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit basic_stringstream(const string_type& __s,
+                                ios_base::openmode __wch = ios_base::in | ios_base::out)
+        : basic_iostream<_CharT, _Traits>(&__sb_)
+        , __sb_(__s, __wch)
+    { }
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_stringstream(basic_stringstream&& __rhs)
+        : basic_iostream<_CharT, _Traits>(_VSTD::move(__rhs))
+        , __sb_(_VSTD::move(__rhs.__sb_))
+    {
+        basic_istream<_CharT, _Traits>::set_rdbuf(&__sb_);
+    }
+
+    // 27.8.2.2 Assign and swap:
+    basic_stringstream& operator=(basic_stringstream&& __rhs) {
+        basic_iostream<char_type, traits_type>::operator=(_VSTD::move(__rhs));
+        __sb_ = _VSTD::move(__rhs.__sb_);
+        return *this;
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(basic_stringstream& __rhs) {
+        basic_iostream<char_type, traits_type>::swap(__rhs);
+        __sb_.swap(__rhs.__sb_);
+    }
+
+    // 27.8.2.3 Members:
+    _LIBCPP_INLINE_VISIBILITY
+    basic_stringbuf<char_type, traits_type, allocator_type>* rdbuf() const {
+        return const_cast<basic_stringbuf<char_type, traits_type, allocator_type>*>(&__sb_);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    string_type str() const {
+        return __sb_.str();
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    void str(const string_type& __s) {
+        __sb_.str(__s);
+    }
+};
+
+template <class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(basic_stringstream<_CharT, _Traits, _Allocator>& __x,
+     basic_stringstream<_CharT, _Traits, _Allocator>& __y)
+{
+    __x.swap(__y);
+}
+
+#if defined(_LIBCPP_ABI_ENABLE_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_stringbuf<char>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_stringstream<char>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ostringstream<char>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_istringstream<char>)
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_SSTREAM
diff --git a/contrib/libs/cxxsupp/libcxx/include/stack b/contrib/libs/cxxsupp/libcxx/include/stack
new file mode 100644
index 00000000000..436993c6f3c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/stack
@@ -0,0 +1,315 @@
+// -*- C++ -*-
+//===---------------------------- stack -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_STACK
+#define _LIBCPP_STACK
+
+/*
+    stack synopsis
+
+namespace std
+{
+
+template <class T, class Container = deque<T>>
+class stack
+{
+public:
+    typedef Container                                container_type;
+    typedef typename container_type::value_type      value_type;
+    typedef typename container_type::reference       reference;
+    typedef typename container_type::const_reference const_reference;
+    typedef typename container_type::size_type       size_type;
+
+protected:
+    container_type c;
+
+public:
+    stack() = default;
+    ~stack() = default;
+
+    stack(const stack& q) = default;
+    stack(stack&& q) = default;
+
+    stack& operator=(const stack& q) = default;
+    stack& operator=(stack&& q) = default;
+
+    explicit stack(const container_type& c);
+    explicit stack(container_type&& c);
+    template <class Alloc> explicit stack(const Alloc& a);
+    template <class Alloc> stack(const container_type& c, const Alloc& a);
+    template <class Alloc> stack(container_type&& c, const Alloc& a);
+    template <class Alloc> stack(const stack& c, const Alloc& a);
+    template <class Alloc> stack(stack&& c, const Alloc& a);
+
+    bool empty() const;
+    size_type size() const;
+    reference top();
+    const_reference top() const;
+
+    void push(const value_type& x);
+    void push(value_type&& x);
+    template <class... Args> reference emplace(Args&&... args); // reference in C++17
+    void pop();
+
+    void swap(stack& c) noexcept(is_nothrow_swappable_v<Container>)
+};
+
+template<class Container>
+  stack(Container) -> stack<typename Container::value_type, Container>;  // C++17
+
+template<class Container, class Allocator>
+  stack(Container, Allocator) -> stack<typename Container::value_type, Container>; // C++17
+
+template <class T, class Container>
+  bool operator==(const stack<T, Container>& x, const stack<T, Container>& y);
+template <class T, class Container>
+  bool operator< (const stack<T, Container>& x, const stack<T, Container>& y);
+template <class T, class Container>
+  bool operator!=(const stack<T, Container>& x, const stack<T, Container>& y);
+template <class T, class Container>
+  bool operator> (const stack<T, Container>& x, const stack<T, Container>& y);
+template <class T, class Container>
+  bool operator>=(const stack<T, Container>& x, const stack<T, Container>& y);
+template <class T, class Container>
+  bool operator<=(const stack<T, Container>& x, const stack<T, Container>& y);
+
+template <class T, class Container>
+  void swap(stack<T, Container>& x, stack<T, Container>& y)
+  noexcept(noexcept(x.swap(y)));
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__memory/uses_allocator.h>
+#include <__utility/forward.h>
+#include <deque>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class _Container = deque<_Tp> > class _LIBCPP_TEMPLATE_VIS stack;
+
+template <class _Tp, class _Container>
+_LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const stack<_Tp, _Container>& __x, const stack<_Tp, _Container>& __y);
+
+template <class _Tp, class _Container>
+_LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const stack<_Tp, _Container>& __x, const stack<_Tp, _Container>& __y);
+
+template <class _Tp, class _Container /*= deque<_Tp>*/>
+class _LIBCPP_TEMPLATE_VIS stack
+{
+public:
+    typedef _Container                               container_type;
+    typedef typename container_type::value_type      value_type;
+    typedef typename container_type::reference       reference;
+    typedef typename container_type::const_reference const_reference;
+    typedef typename container_type::size_type       size_type;
+    static_assert((is_same<_Tp, value_type>::value), "" );
+
+protected:
+    container_type c;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    stack()
+        _NOEXCEPT_(is_nothrow_default_constructible<container_type>::value)
+        : c() {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    stack(const stack& __q) : c(__q.c) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    stack& operator=(const stack& __q) {c = __q.c; return *this;}
+
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    stack(stack&& __q)
+        _NOEXCEPT_(is_nothrow_move_constructible<container_type>::value)
+        : c(_VSTD::move(__q.c)) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    stack& operator=(stack&& __q)
+        _NOEXCEPT_(is_nothrow_move_assignable<container_type>::value)
+        {c = _VSTD::move(__q.c); return *this;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit stack(container_type&& __c) : c(_VSTD::move(__c)) {}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit stack(const container_type& __c) : c(__c) {}
+
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        explicit stack(const _Alloc& __a,
+                       __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0)
+            : c(__a) {}
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        stack(const container_type& __c, const _Alloc& __a,
+              __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0)
+            : c(__c, __a) {}
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        stack(const stack& __s, const _Alloc& __a,
+              __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0)
+            : c(__s.c, __a) {}
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        stack(container_type&& __c, const _Alloc& __a,
+              __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0)
+            : c(_VSTD::move(__c), __a) {}
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY
+        stack(stack&& __s, const _Alloc& __a,
+              __enable_if_t<uses_allocator<container_type, _Alloc>::value>* = 0)
+            : c(_VSTD::move(__s.c), __a) {}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool empty()     const      {return c.empty();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const      {return c.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    reference top()             {return c.back();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference top() const {return c.back();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void push(const value_type& __v) {c.push_back(__v);}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void push(value_type&& __v) {c.push_back(_VSTD::move(__v));}
+
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+#if _LIBCPP_STD_VER > 14
+        decltype(auto) emplace(_Args&&... __args)
+        { return c.emplace_back(_VSTD::forward<_Args>(__args)...);}
+#else
+        void      emplace(_Args&&... __args)
+        {        c.emplace_back(_VSTD::forward<_Args>(__args)...);}
+#endif
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    void pop() {c.pop_back();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(stack& __s)
+        _NOEXCEPT_(__is_nothrow_swappable<container_type>::value)
+    {
+        using _VSTD::swap;
+        swap(c, __s.c);
+    }
+
+    template <class T1, class _C1>
+    friend
+    bool
+    operator==(const stack<T1, _C1>& __x, const stack<T1, _C1>& __y);
+
+    template <class T1, class _C1>
+    friend
+    bool
+    operator< (const stack<T1, _C1>& __x, const stack<T1, _C1>& __y);
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _Container,
+         class = enable_if_t<!__is_allocator<_Container>::value>
+>
+stack(_Container)
+    -> stack<typename _Container::value_type, _Container>;
+
+template<class _Container,
+         class _Alloc,
+         class = enable_if_t<!__is_allocator<_Container>::value>,
+         class = enable_if_t<uses_allocator<_Container, _Alloc>::value>
+         >
+stack(_Container, _Alloc)
+    -> stack<typename _Container::value_type, _Container>;
+#endif
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const stack<_Tp, _Container>& __x, const stack<_Tp, _Container>& __y)
+{
+    return __x.c == __y.c;
+}
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const stack<_Tp, _Container>& __x, const stack<_Tp, _Container>& __y)
+{
+    return __x.c < __y.c;
+}
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const stack<_Tp, _Container>& __x, const stack<_Tp, _Container>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const stack<_Tp, _Container>& __x, const stack<_Tp, _Container>& __y)
+{
+    return __y < __x;
+}
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const stack<_Tp, _Container>& __x, const stack<_Tp, _Container>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const stack<_Tp, _Container>& __x, const stack<_Tp, _Container>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _Tp, class _Container>
+inline _LIBCPP_INLINE_VISIBILITY
+__enable_if_t<__is_swappable<_Container>::value, void>
+swap(stack<_Tp, _Container>& __x, stack<_Tp, _Container>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+template <class _Tp, class _Container, class _Alloc>
+struct _LIBCPP_TEMPLATE_VIS uses_allocator<stack<_Tp, _Container>, _Alloc>
+    : public uses_allocator<_Container, _Alloc>
+{
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STACK
diff --git a/contrib/libs/cxxsupp/libcxx/include/stdbool.h b/contrib/libs/cxxsupp/libcxx/include/stdbool.h
new file mode 100644
index 00000000000..08229b8ed98
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/stdbool.h
@@ -0,0 +1,42 @@
+// -*- C++ -*-
+//===--------------------------- stdbool.h --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP_STDBOOL_H
+#define _LIBCPP_STDBOOL_H
+
+
+/*
+    stdbool.h synopsis
+
+Macros:
+
+    __bool_true_false_are_defined
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_MSVC_INCLUDE(stdbool.h)
+#else
+#include_next <stdbool.h>
+#endif
+
+#ifdef __cplusplus
+#undef bool
+#undef true
+#undef false
+#undef __bool_true_false_are_defined
+#define __bool_true_false_are_defined 1
+#endif
+
+#endif // _LIBCPP_STDBOOL_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/stddef.h b/contrib/libs/cxxsupp/libcxx/include/stddef.h
new file mode 100644
index 00000000000..bee1edb40dc
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/stddef.h
@@ -0,0 +1,65 @@
+// -*- C++ -*-
+//===--------------------------- stddef.h ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#if defined(__need_ptrdiff_t) || defined(__need_size_t) || \
+    defined(__need_wchar_t) || defined(__need_NULL) || defined(__need_wint_t)
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(stddef.h)
+#else
+#include_next <stddef.h>
+#endif
+
+#elif !defined(_LIBCPP_STDDEF_H)
+#define _LIBCPP_STDDEF_H
+
+/*
+    stddef.h synopsis
+
+Macros:
+
+    offsetof(type,member-designator)
+    NULL
+
+Types:
+
+    ptrdiff_t
+    size_t
+    max_align_t // C++11
+    nullptr_t
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(stddef.h)
+typedef double max_align_t;
+#else
+#include_next <stddef.h>
+#endif
+
+#ifdef __cplusplus
+
+extern "C++" {
+#include <__nullptr>
+using std::nullptr_t;
+}
+
+#endif
+
+#endif // _LIBCPP_STDDEF_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/stdexcept b/contrib/libs/cxxsupp/libcxx/include/stdexcept
new file mode 100644
index 00000000000..c0470d1e1dd
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/stdexcept
@@ -0,0 +1,309 @@
+// -*- C++ -*-
+//===--------------------------- stdexcept --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_STDEXCEPT
+#define _LIBCPP_STDEXCEPT
+
+/*
+    stdexcept synopsis
+
+namespace std
+{
+
+class logic_error;
+    class domain_error;
+    class invalid_argument;
+    class length_error;
+    class out_of_range;
+class runtime_error;
+    class range_error;
+    class overflow_error;
+    class underflow_error;
+
+for each class xxx_error:
+
+class xxx_error : public exception // at least indirectly
+{
+public:
+    explicit xxx_error(const string& what_arg);
+    explicit xxx_error(const char*   what_arg);
+
+    virtual const char* what() const noexcept // returns what_arg
+};
+
+}  // std
+
+*/
+
+#include <__config>
+#include <exception>
+#include <iosfwd>  // for string forward decl
+#include <cstdlib>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_ABI_VCRUNTIME
+class _LIBCPP_HIDDEN __libcpp_refstring
+{
+    const char* __imp_;
+
+    bool __uses_refcount() const;
+public:
+    explicit __libcpp_refstring(const char* __msg);
+    __libcpp_refstring(const __libcpp_refstring& __s) _NOEXCEPT;
+    __libcpp_refstring& operator=(const __libcpp_refstring& __s) _NOEXCEPT;
+    ~__libcpp_refstring();
+
+    const char* c_str() const _NOEXCEPT {return __imp_;}
+};
+#endif // !_LIBCPP_ABI_VCRUNTIME
+
+_LIBCPP_END_NAMESPACE_STD
+
+namespace std  // purposefully not using versioning namespace
+{
+
+class _LIBCPP_EXCEPTION_ABI logic_error
+    : public exception
+{
+#ifndef _LIBCPP_ABI_VCRUNTIME
+private:
+    _VSTD::__libcpp_refstring __imp_;
+public:
+    explicit logic_error(const string&);
+    explicit logic_error(const char*);
+
+    logic_error(const logic_error&) _NOEXCEPT;
+    logic_error& operator=(const logic_error&) _NOEXCEPT;
+
+    virtual ~logic_error() _NOEXCEPT;
+
+    virtual const char* what() const _NOEXCEPT;
+#else
+public:
+    explicit logic_error(const _VSTD::string&); // Symbol uses versioned std::string
+    _LIBCPP_INLINE_VISIBILITY explicit logic_error(const char* __s) : exception(__s) {}
+#endif
+};
+
+class _LIBCPP_EXCEPTION_ABI runtime_error
+    : public exception
+{
+#ifndef _LIBCPP_ABI_VCRUNTIME
+private:
+    _VSTD::__libcpp_refstring __imp_;
+public:
+    explicit runtime_error(const string&);
+    explicit runtime_error(const char*);
+
+    runtime_error(const runtime_error&) _NOEXCEPT;
+    runtime_error& operator=(const runtime_error&) _NOEXCEPT;
+
+    virtual ~runtime_error() _NOEXCEPT;
+
+    virtual const char* what() const _NOEXCEPT;
+#else
+public:
+   explicit runtime_error(const _VSTD::string&); // Symbol uses versioned std::string
+   _LIBCPP_INLINE_VISIBILITY explicit runtime_error(const char* __s) : exception(__s) {}
+#endif // _LIBCPP_ABI_VCRUNTIME
+};
+
+class _LIBCPP_EXCEPTION_ABI domain_error
+    : public logic_error
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit domain_error(const string& __s) : logic_error(__s) {}
+    _LIBCPP_INLINE_VISIBILITY explicit domain_error(const char* __s)   : logic_error(__s) {}
+
+#ifndef _LIBCPP_ABI_VCRUNTIME
+    domain_error(const domain_error&) _NOEXCEPT = default;
+    virtual ~domain_error() _NOEXCEPT;
+#endif
+};
+
+class _LIBCPP_EXCEPTION_ABI invalid_argument
+    : public logic_error
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit invalid_argument(const string& __s) : logic_error(__s) {}
+    _LIBCPP_INLINE_VISIBILITY explicit invalid_argument(const char* __s)   : logic_error(__s) {}
+
+#ifndef _LIBCPP_ABI_VCRUNTIME
+    invalid_argument(const invalid_argument&) _NOEXCEPT = default;
+    virtual ~invalid_argument() _NOEXCEPT;
+#endif
+};
+
+class _LIBCPP_EXCEPTION_ABI length_error
+    : public logic_error
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit length_error(const string& __s) : logic_error(__s) {}
+    _LIBCPP_INLINE_VISIBILITY explicit length_error(const char* __s)   : logic_error(__s) {}
+#ifndef _LIBCPP_ABI_VCRUNTIME
+    length_error(const length_error&) _NOEXCEPT = default;
+    virtual ~length_error() _NOEXCEPT;
+#endif
+};
+
+class _LIBCPP_EXCEPTION_ABI out_of_range
+    : public logic_error
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit out_of_range(const string& __s) : logic_error(__s) {}
+    _LIBCPP_INLINE_VISIBILITY explicit out_of_range(const char* __s)   : logic_error(__s) {}
+
+#ifndef _LIBCPP_ABI_VCRUNTIME
+    out_of_range(const out_of_range&) _NOEXCEPT = default;
+    virtual ~out_of_range() _NOEXCEPT;
+#endif
+};
+
+class _LIBCPP_EXCEPTION_ABI range_error
+    : public runtime_error
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit range_error(const string& __s) : runtime_error(__s) {}
+    _LIBCPP_INLINE_VISIBILITY explicit range_error(const char* __s)   : runtime_error(__s) {}
+
+#ifndef _LIBCPP_ABI_VCRUNTIME
+    range_error(const range_error&) _NOEXCEPT = default;
+    virtual ~range_error() _NOEXCEPT;
+#endif
+};
+
+class _LIBCPP_EXCEPTION_ABI overflow_error
+    : public runtime_error
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit overflow_error(const string& __s) : runtime_error(__s) {}
+    _LIBCPP_INLINE_VISIBILITY explicit overflow_error(const char* __s)   : runtime_error(__s) {}
+
+#ifndef _LIBCPP_ABI_VCRUNTIME
+    overflow_error(const overflow_error&) _NOEXCEPT = default;
+    virtual ~overflow_error() _NOEXCEPT;
+#endif
+};
+
+class _LIBCPP_EXCEPTION_ABI underflow_error
+    : public runtime_error
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY explicit underflow_error(const string& __s) : runtime_error(__s) {}
+    _LIBCPP_INLINE_VISIBILITY explicit underflow_error(const char* __s)   : runtime_error(__s) {}
+
+#ifndef _LIBCPP_ABI_VCRUNTIME
+    underflow_error(const underflow_error&) _NOEXCEPT = default;
+    virtual ~underflow_error() _NOEXCEPT;
+#endif
+};
+
+}  // std
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// in the dylib
+_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void __throw_runtime_error(const char*);
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+void __throw_logic_error(const char*__msg)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw logic_error(__msg);
+#else
+    ((void)__msg);
+    _VSTD::abort();
+#endif
+}
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+void __throw_domain_error(const char*__msg)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw domain_error(__msg);
+#else
+    ((void)__msg);
+    _VSTD::abort();
+#endif
+}
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+void __throw_invalid_argument(const char*__msg)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw invalid_argument(__msg);
+#else
+    ((void)__msg);
+    _VSTD::abort();
+#endif
+}
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+void __throw_length_error(const char*__msg)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw length_error(__msg);
+#else
+    ((void)__msg);
+    _VSTD::abort();
+#endif
+}
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+void __throw_out_of_range(const char*__msg)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw out_of_range(__msg);
+#else
+    ((void)__msg);
+    _VSTD::abort();
+#endif
+}
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+void __throw_range_error(const char*__msg)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw range_error(__msg);
+#else
+    ((void)__msg);
+    _VSTD::abort();
+#endif
+}
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+void __throw_overflow_error(const char*__msg)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw overflow_error(__msg);
+#else
+    ((void)__msg);
+    _VSTD::abort();
+#endif
+}
+
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+void __throw_underflow_error(const char*__msg)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw underflow_error(__msg);
+#else
+    ((void)__msg);
+    _VSTD::abort();
+#endif
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STDEXCEPT
diff --git a/contrib/libs/cxxsupp/libcxx/include/stdint.h b/contrib/libs/cxxsupp/libcxx/include/stdint.h
new file mode 100644
index 00000000000..73f57000eb6
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/stdint.h
@@ -0,0 +1,129 @@
+// -*- C++ -*-
+//===---------------------------- stdint.h --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_STDINT_H
+// AIX system headers need stdint.h to be re-enterable while _STD_TYPES_T
+// is defined until an inclusion of it without _STD_TYPES_T occurs, in which
+// case the header guard macro is defined.
+#if !defined(_AIX) || !defined(_STD_TYPES_T)
+#define _LIBCPP_STDINT_H
+#endif // _STD_TYPES_T
+
+/*
+    stdint.h synopsis
+
+Macros:
+
+    INT8_MIN
+    INT16_MIN
+    INT32_MIN
+    INT64_MIN
+
+    INT8_MAX
+    INT16_MAX
+    INT32_MAX
+    INT64_MAX
+
+    UINT8_MAX
+    UINT16_MAX
+    UINT32_MAX
+    UINT64_MAX
+
+    INT_LEAST8_MIN
+    INT_LEAST16_MIN
+    INT_LEAST32_MIN
+    INT_LEAST64_MIN
+
+    INT_LEAST8_MAX
+    INT_LEAST16_MAX
+    INT_LEAST32_MAX
+    INT_LEAST64_MAX
+
+    UINT_LEAST8_MAX
+    UINT_LEAST16_MAX
+    UINT_LEAST32_MAX
+    UINT_LEAST64_MAX
+
+    INT_FAST8_MIN
+    INT_FAST16_MIN
+    INT_FAST32_MIN
+    INT_FAST64_MIN
+
+    INT_FAST8_MAX
+    INT_FAST16_MAX
+    INT_FAST32_MAX
+    INT_FAST64_MAX
+
+    UINT_FAST8_MAX
+    UINT_FAST16_MAX
+    UINT_FAST32_MAX
+    UINT_FAST64_MAX
+
+    INTPTR_MIN
+    INTPTR_MAX
+    UINTPTR_MAX
+
+    INTMAX_MIN
+    INTMAX_MAX
+
+    UINTMAX_MAX
+
+    PTRDIFF_MIN
+    PTRDIFF_MAX
+
+    SIG_ATOMIC_MIN
+    SIG_ATOMIC_MAX
+
+    SIZE_MAX
+
+    WCHAR_MIN
+    WCHAR_MAX
+
+    WINT_MIN
+    WINT_MAX
+
+    INT8_C(value)
+    INT16_C(value)
+    INT32_C(value)
+    INT64_C(value)
+
+    UINT8_C(value)
+    UINT16_C(value)
+    UINT32_C(value)
+    UINT64_C(value)
+
+    INTMAX_C(value)
+    UINTMAX_C(value)
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+/* C99 stdlib (e.g. glibc < 2.18) does not provide macros needed
+   for C++11 unless __STDC_LIMIT_MACROS and __STDC_CONSTANT_MACROS
+   are defined
+*/
+#if defined(__cplusplus) && !defined(__STDC_LIMIT_MACROS)
+#   define __STDC_LIMIT_MACROS
+#endif
+#if defined(__cplusplus) && !defined(__STDC_CONSTANT_MACROS)
+#   define __STDC_CONSTANT_MACROS
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_MSVC_INCLUDE(stdint.h)
+#else
+#include_next <stdint.h>
+#endif
+
+#endif // _LIBCPP_STDINT_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/stdio.h b/contrib/libs/cxxsupp/libcxx/include/stdio.h
new file mode 100644
index 00000000000..9d4ea634a55
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/stdio.h
@@ -0,0 +1,127 @@
+// -*- C++ -*-
+//===---------------------------- stdio.h ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#if defined(__need_FILE) || defined(__need___FILE)
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(stdio.h)
+#else
+#include_next <stdio.h>
+#endif
+
+#elif !defined(_LIBCPP_STDIO_H)
+#define _LIBCPP_STDIO_H
+
+/*
+    stdio.h synopsis
+
+Macros:
+
+    BUFSIZ
+    EOF
+    FILENAME_MAX
+    FOPEN_MAX
+    L_tmpnam
+    NULL
+    SEEK_CUR
+    SEEK_END
+    SEEK_SET
+    TMP_MAX
+    _IOFBF
+    _IOLBF
+    _IONBF
+    stderr
+    stdin
+    stdout
+
+Types:
+
+FILE
+fpos_t
+size_t
+
+int remove(const char* filename);
+int rename(const char* old, const char* new);
+FILE* tmpfile(void);
+char* tmpnam(char* s);
+int fclose(FILE* stream);
+int fflush(FILE* stream);
+FILE* fopen(const char* restrict filename, const char* restrict mode);
+FILE* freopen(const char* restrict filename, const char * restrict mode,
+              FILE * restrict stream);
+void setbuf(FILE* restrict stream, char* restrict buf);
+int setvbuf(FILE* restrict stream, char* restrict buf, int mode, size_t size);
+int fprintf(FILE* restrict stream, const char* restrict format, ...);
+int fscanf(FILE* restrict stream, const char * restrict format, ...);
+int printf(const char* restrict format, ...);
+int scanf(const char* restrict format, ...);
+int snprintf(char* restrict s, size_t n, const char* restrict format, ...);    // C99
+int sprintf(char* restrict s, const char* restrict format, ...);
+int sscanf(const char* restrict s, const char* restrict format, ...);
+int vfprintf(FILE* restrict stream, const char* restrict format, va_list arg);
+int vfscanf(FILE* restrict stream, const char* restrict format, va_list arg);  // C99
+int vprintf(const char* restrict format, va_list arg);
+int vscanf(const char* restrict format, va_list arg);                          // C99
+int vsnprintf(char* restrict s, size_t n, const char* restrict format,         // C99
+              va_list arg);
+int vsprintf(char* restrict s, const char* restrict format, va_list arg);
+int vsscanf(const char* restrict s, const char* restrict format, va_list arg); // C99
+int fgetc(FILE* stream);
+char* fgets(char* restrict s, int n, FILE* restrict stream);
+int fputc(int c, FILE* stream);
+int fputs(const char* restrict s, FILE* restrict stream);
+int getc(FILE* stream);
+int getchar(void);
+char* gets(char* s);  // removed in C++14
+int putc(int c, FILE* stream);
+int putchar(int c);
+int puts(const char* s);
+int ungetc(int c, FILE* stream);
+size_t fread(void* restrict ptr, size_t size, size_t nmemb,
+             FILE* restrict stream);
+size_t fwrite(const void* restrict ptr, size_t size, size_t nmemb,
+              FILE* restrict stream);
+int fgetpos(FILE* restrict stream, fpos_t* restrict pos);
+int fseek(FILE* stream, long offset, int whence);
+int fsetpos(FILE*stream, const fpos_t* pos);
+long ftell(FILE* stream);
+void rewind(FILE* stream);
+void clearerr(FILE* stream);
+int feof(FILE* stream);
+int ferror(FILE* stream);
+void perror(const char* s);
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(stdio.h)
+#else
+#include_next <stdio.h>
+#endif
+
+#ifdef __cplusplus
+
+#undef getc
+#undef putc
+#undef clearerr
+#undef feof
+#undef ferror
+
+#endif
+
+#endif // _LIBCPP_STDIO_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/stdlib.h b/contrib/libs/cxxsupp/libcxx/include/stdlib.h
new file mode 100644
index 00000000000..45da948184f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/stdlib.h
@@ -0,0 +1,190 @@
+// -*- C++ -*-
+//===--------------------------- stdlib.h ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#if defined(__need_malloc_and_calloc)
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(stdlib.h)
+#else
+#include_next <stdlib.h>
+#endif
+
+#elif !defined(_LIBCPP_STDLIB_H)
+#define _LIBCPP_STDLIB_H
+
+/*
+    stdlib.h synopsis
+
+Macros:
+
+    EXIT_FAILURE
+    EXIT_SUCCESS
+    MB_CUR_MAX
+    NULL
+    RAND_MAX
+
+Types:
+
+    size_t
+    div_t
+    ldiv_t
+    lldiv_t                                                               // C99
+
+double    atof (const char* nptr);
+int       atoi (const char* nptr);
+long      atol (const char* nptr);
+long long atoll(const char* nptr);                                        // C99
+double             strtod  (const char* restrict nptr, char** restrict endptr);
+float              strtof  (const char* restrict nptr, char** restrict endptr); // C99
+long double        strtold (const char* restrict nptr, char** restrict endptr); // C99
+long               strtol  (const char* restrict nptr, char** restrict endptr, int base);
+long long          strtoll (const char* restrict nptr, char** restrict endptr, int base); // C99
+unsigned long      strtoul (const char* restrict nptr, char** restrict endptr, int base);
+unsigned long long strtoull(const char* restrict nptr, char** restrict endptr, int base); // C99
+int rand(void);
+void srand(unsigned int seed);
+void* calloc(size_t nmemb, size_t size);
+void free(void* ptr);
+void* malloc(size_t size);
+void* realloc(void* ptr, size_t size);
+void abort(void);
+int atexit(void (*func)(void));
+void exit(int status);
+void _Exit(int status);
+char* getenv(const char* name);
+int system(const char* string);
+void* bsearch(const void* key, const void* base, size_t nmemb, size_t size,
+              int (*compar)(const void *, const void *));
+void qsort(void* base, size_t nmemb, size_t size,
+           int (*compar)(const void *, const void *));
+int         abs(      int j);
+long        abs(     long j);
+long long   abs(long long j);                                             // C++0X
+long       labs(     long j);
+long long llabs(long long j);                                             // C99
+div_t     div(      int numer,       int denom);
+ldiv_t    div(     long numer,      long denom);
+lldiv_t   div(long long numer, long long denom);                          // C++0X
+ldiv_t   ldiv(     long numer,      long denom);
+lldiv_t lldiv(long long numer, long long denom);                          // C99
+int mblen(const char* s, size_t n);
+int mbtowc(wchar_t* restrict pwc, const char* restrict s, size_t n);
+int wctomb(char* s, wchar_t wchar);
+size_t mbstowcs(wchar_t* restrict pwcs, const char* restrict s, size_t n);
+size_t wcstombs(char* restrict s, const wchar_t* restrict pwcs, size_t n);
+int at_quick_exit(void (*func)(void))                                     // C++11
+void quick_exit(int status);                                              // C++11
+void *aligned_alloc(size_t alignment, size_t size);                       // C11
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(stdlib.h)
+#ifdef __cplusplus
+extern "C" {
+#endif
+float fabsf(float);
+double fabs(double);
+long double fabsl(long double);
+#ifdef __cplusplus
+}
+#endif
+#else
+#include_next <stdlib.h>
+#endif
+
+#ifdef __cplusplus
+extern "C++" {
+// abs
+
+#ifdef abs
+# undef abs
+#endif
+#ifdef labs
+# undef labs
+#endif
+#ifdef llabs
+# undef llabs
+#endif
+
+// MSVCRT already has the correct prototype in <stdlib.h> if __cplusplus is defined
+#if !defined(_LIBCPP_MSVCRT) && !defined(__sun__)
+inline _LIBCPP_INLINE_VISIBILITY long abs(long __x) _NOEXCEPT {
+  return __builtin_labs(__x);
+}
+inline _LIBCPP_INLINE_VISIBILITY long long abs(long long __x) _NOEXCEPT {
+  return __builtin_llabs(__x);
+}
+#endif // !defined(_LIBCPP_MSVCRT) && !defined(__sun__)
+
+#if !defined(__sun__)
+inline _LIBCPP_INLINE_VISIBILITY float abs(float __lcpp_x) _NOEXCEPT {
+#ifdef _LIBCPP_COMPILER_MSVC
+  return fabsf(__lcpp_x);
+#else
+  return __builtin_fabsf(__lcpp_x); // Use builtins to prevent needing math.h
+#endif
+}
+
+inline _LIBCPP_INLINE_VISIBILITY double abs(double __lcpp_x) _NOEXCEPT {
+#ifdef _LIBCPP_COMPILER_MSVC
+  return fabs(__lcpp_x);
+#else
+  return __builtin_fabs(__lcpp_x);
+#endif
+}
+
+inline _LIBCPP_INLINE_VISIBILITY long double
+abs(long double __lcpp_x) _NOEXCEPT {
+#ifdef _LIBCPP_COMPILER_MSVC
+  return fabsl(__lcpp_x);
+#else
+  return __builtin_fabsl(__lcpp_x);
+#endif
+}
+#endif // !defined(__sun__)
+
+// div
+
+#ifdef div
+# undef div
+#endif
+#ifdef ldiv
+# undef ldiv
+#endif
+#ifdef lldiv
+# undef lldiv
+#endif
+
+// MSVCRT already has the correct prototype in <stdlib.h> if __cplusplus is defined
+#if !defined(_LIBCPP_MSVCRT) && !defined(__sun__)
+inline _LIBCPP_INLINE_VISIBILITY ldiv_t div(long __x, long __y) _NOEXCEPT {
+  return ::ldiv(__x, __y);
+}
+#if !(defined(__FreeBSD__) && !defined(__LONG_LONG_SUPPORTED))
+inline _LIBCPP_INLINE_VISIBILITY lldiv_t div(long long __x,
+                                             long long __y) _NOEXCEPT {
+  return ::lldiv(__x, __y);
+}
+#endif
+#endif // _LIBCPP_MSVCRT / __sun__
+} // extern "C++"
+#endif // __cplusplus
+
+#endif // _LIBCPP_STDLIB_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/stlfwd b/contrib/libs/cxxsupp/libcxx/include/stlfwd
new file mode 100644
index 00000000000..adad6790dcc
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/stlfwd
@@ -0,0 +1,63 @@
+#pragma once
+
+#include <__config>
+#include <cstddef>
+#include <iosfwd>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+    template <class F, class S>
+    struct pair;
+
+    template <class T, size_t N>
+    struct array;
+
+    template <class T, class A>
+    class vector;
+
+    template <class T, class A>
+    class list;
+
+    template <class T, class A>
+    class deque;
+
+    template <class T, class C, class A>
+    class set;
+
+    template <class T, class C, class A>
+    class multiset;
+
+    template <class K, class V, class C, class A>
+    class map;
+
+    template <class K, class V, class C, class A>
+    class multimap;
+
+    template <typename... TArgs>
+    class tuple;
+
+    constexpr void get(...) = delete;
+
+    template <class>
+    class _LIBCPP_TEMPLATE_VIS function;
+
+    template <class _Tp>
+    struct _LIBCPP_TEMPLATE_VIS default_delete;
+
+    template <class _Tp, class Deleter = default_delete<_Tp>>
+    class _LIBCPP_TEMPLATE_VIS unique_ptr;
+
+    template <class T>
+    class _LIBCPP_TEMPLATE_VIS shared_ptr;
+
+    /* basic_string is already forward-declared in <iosfwd> */
+
+    template<class T, class Traits>
+    class basic_string_view;
+
+_LIBCPP_END_NAMESPACE_STD
+
diff --git a/contrib/libs/cxxsupp/libcxx/include/streambuf b/contrib/libs/cxxsupp/libcxx/include/streambuf
new file mode 100644
index 00000000000..385d4869458
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/streambuf
@@ -0,0 +1,498 @@
+// -*- C++ -*-
+//===------------------------- streambuf ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_STREAMBUF
+#define _LIBCPP_STREAMBUF
+
+/*
+    streambuf synopsis
+
+namespace std
+{
+
+template <class charT, class traits = char_traits<charT> >
+class basic_streambuf
+{
+public:
+    // types:
+    typedef charT char_type;
+    typedef traits traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    virtual ~basic_streambuf();
+
+    // 27.6.2.2.1 locales:
+    locale pubimbue(const locale& loc);
+    locale getloc() const;
+
+    // 27.6.2.2.2 buffer and positioning:
+    basic_streambuf* pubsetbuf(char_type* s, streamsize n);
+    pos_type pubseekoff(off_type off, ios_base::seekdir way,
+                        ios_base::openmode which = ios_base::in | ios_base::out);
+    pos_type pubseekpos(pos_type sp,
+                        ios_base::openmode which = ios_base::in | ios_base::out);
+    int pubsync();
+
+    // Get and put areas:
+    // 27.6.2.2.3 Get area:
+    streamsize in_avail();
+    int_type snextc();
+    int_type sbumpc();
+    int_type sgetc();
+    streamsize sgetn(char_type* s, streamsize n);
+
+    // 27.6.2.2.4 Putback:
+    int_type sputbackc(char_type c);
+    int_type sungetc();
+
+    // 27.6.2.2.5 Put area:
+    int_type sputc(char_type c);
+    streamsize sputn(const char_type* s, streamsize n);
+
+protected:
+    basic_streambuf();
+    basic_streambuf(const basic_streambuf& rhs);
+    basic_streambuf& operator=(const basic_streambuf& rhs);
+    void swap(basic_streambuf& rhs);
+
+    // 27.6.2.3.2 Get area:
+    char_type* eback() const;
+    char_type* gptr() const;
+    char_type* egptr() const;
+    void gbump(int n);
+    void setg(char_type* gbeg, char_type* gnext, char_type* gend);
+
+    // 27.6.2.3.3 Put area:
+    char_type* pbase() const;
+    char_type* pptr() const;
+    char_type* epptr() const;
+    void pbump(int n);
+    void setp(char_type* pbeg, char_type* pend);
+
+    // 27.6.2.4 virtual functions:
+    // 27.6.2.4.1 Locales:
+    virtual void imbue(const locale& loc);
+
+    // 27.6.2.4.2 Buffer management and positioning:
+    virtual basic_streambuf* setbuf(char_type* s, streamsize n);
+    virtual pos_type seekoff(off_type off, ios_base::seekdir way,
+                             ios_base::openmode which = ios_base::in | ios_base::out);
+    virtual pos_type seekpos(pos_type sp,
+                             ios_base::openmode which = ios_base::in | ios_base::out);
+    virtual int sync();
+
+    // 27.6.2.4.3 Get area:
+    virtual streamsize showmanyc();
+    virtual streamsize xsgetn(char_type* s, streamsize n);
+    virtual int_type underflow();
+    virtual int_type uflow();
+
+    // 27.6.2.4.4 Putback:
+    virtual int_type pbackfail(int_type c = traits_type::eof());
+
+    // 27.6.2.4.5 Put area:
+    virtual streamsize xsputn(const char_type* s, streamsize n);
+    virtual int_type overflow (int_type c = traits_type::eof());
+};
+
+}  // std
+
+*/
+
+#include <__config>
+#include <ios>
+#include <iosfwd>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _CharT, class _Traits>
+class _LIBCPP_TEMPLATE_VIS basic_streambuf
+{
+public:
+    // types:
+    typedef _CharT                         char_type;
+    typedef _Traits                        traits_type;
+    typedef typename traits_type::int_type int_type;
+    typedef typename traits_type::pos_type pos_type;
+    typedef typename traits_type::off_type off_type;
+
+    static_assert((is_same<_CharT, typename traits_type::char_type>::value),
+                  "traits_type::char_type must be the same type as CharT");
+
+    virtual ~basic_streambuf();
+
+    // 27.6.2.2.1 locales:
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    locale pubimbue(const locale& __loc) {
+        imbue(__loc);
+        locale __r = __loc_;
+        __loc_ = __loc;
+        return __r;
+    }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    locale getloc() const { return __loc_; }
+
+    // 27.6.2.2.2 buffer and positioning:
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    basic_streambuf* pubsetbuf(char_type* __s, streamsize __n)
+    { return setbuf(__s, __n); }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    pos_type pubseekoff(off_type __off, ios_base::seekdir __way,
+                        ios_base::openmode __which = ios_base::in | ios_base::out)
+    { return seekoff(__off, __way, __which); }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    pos_type pubseekpos(pos_type __sp,
+                        ios_base::openmode __which = ios_base::in | ios_base::out)
+    { return seekpos(__sp, __which); }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    int pubsync() { return sync(); }
+
+    // Get and put areas:
+    // 27.6.2.2.3 Get area:
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    streamsize in_avail() {
+        if (__ninp_ < __einp_)
+            return static_cast<streamsize>(__einp_ - __ninp_);
+        return showmanyc();
+    }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    int_type snextc() {
+        if (sbumpc() == traits_type::eof())
+            return traits_type::eof();
+        return sgetc();
+    }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    int_type sbumpc() {
+        if (__ninp_ == __einp_)
+            return uflow();
+        return traits_type::to_int_type(*__ninp_++);
+    }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    int_type sgetc() {
+        if (__ninp_ == __einp_)
+            return underflow();
+        return traits_type::to_int_type(*__ninp_);
+    }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    streamsize sgetn(char_type* __s, streamsize __n)
+    { return xsgetn(__s, __n); }
+
+    // 27.6.2.2.4 Putback:
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    int_type sputbackc(char_type __c) {
+        if (__binp_ == __ninp_ || !traits_type::eq(__c, __ninp_[-1]))
+            return pbackfail(traits_type::to_int_type(__c));
+        return traits_type::to_int_type(*--__ninp_);
+    }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    int_type sungetc() {
+        if (__binp_ == __ninp_)
+          return pbackfail();
+        return traits_type::to_int_type(*--__ninp_);
+    }
+
+    // 27.6.2.2.5 Put area:
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    int_type sputc(char_type __c) {
+        if (__nout_ == __eout_)
+            return overflow(traits_type::to_int_type(__c));
+        *__nout_++ = __c;
+        return traits_type::to_int_type(__c);
+    }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    streamsize sputn(const char_type* __s, streamsize __n)
+    { return xsputn(__s, __n); }
+
+protected:
+    basic_streambuf();
+    basic_streambuf(const basic_streambuf& __rhs);
+    basic_streambuf& operator=(const basic_streambuf& __rhs);
+    void swap(basic_streambuf& __rhs);
+
+    // 27.6.2.3.2 Get area:
+    _LIBCPP_INLINE_VISIBILITY char_type* eback() const {return __binp_;}
+    _LIBCPP_INLINE_VISIBILITY char_type* gptr()  const {return __ninp_;}
+    _LIBCPP_INLINE_VISIBILITY char_type* egptr() const {return __einp_;}
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    void gbump(int __n) { __ninp_ += __n; }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    void setg(char_type* __gbeg, char_type* __gnext, char_type* __gend) {
+        __binp_ = __gbeg;
+        __ninp_ = __gnext;
+        __einp_ = __gend;
+    }
+
+    // 27.6.2.3.3 Put area:
+    _LIBCPP_INLINE_VISIBILITY char_type* pbase() const {return __bout_;}
+    _LIBCPP_INLINE_VISIBILITY char_type* pptr()  const {return __nout_;}
+    _LIBCPP_INLINE_VISIBILITY char_type* epptr() const {return __eout_;}
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    void pbump(int __n) { __nout_ += __n; }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __pbump(streamsize __n) { __nout_ += __n; }
+
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    void setp(char_type* __pbeg, char_type* __pend) {
+        __bout_ = __nout_ = __pbeg;
+        __eout_ = __pend;
+    }
+
+    // 27.6.2.4 virtual functions:
+    // 27.6.2.4.1 Locales:
+    virtual void imbue(const locale& __loc);
+
+    // 27.6.2.4.2 Buffer management and positioning:
+    virtual basic_streambuf* setbuf(char_type* __s, streamsize __n);
+    virtual pos_type seekoff(off_type __off, ios_base::seekdir __way,
+                             ios_base::openmode __which = ios_base::in | ios_base::out);
+    virtual pos_type seekpos(pos_type __sp,
+                             ios_base::openmode __which = ios_base::in | ios_base::out);
+    virtual int sync();
+
+    // 27.6.2.4.3 Get area:
+    virtual streamsize showmanyc();
+    virtual streamsize xsgetn(char_type* __s, streamsize __n);
+    virtual int_type underflow();
+    virtual int_type uflow();
+
+    // 27.6.2.4.4 Putback:
+    virtual int_type pbackfail(int_type __c = traits_type::eof());
+
+    // 27.6.2.4.5 Put area:
+    virtual streamsize xsputn(const char_type* __s, streamsize __n);
+    virtual int_type overflow(int_type __c = traits_type::eof());
+
+private:
+    locale __loc_;
+    char_type* __binp_;
+    char_type* __ninp_;
+    char_type* __einp_;
+    char_type* __bout_;
+    char_type* __nout_;
+    char_type* __eout_;
+};
+
+template <class _CharT, class _Traits>
+basic_streambuf<_CharT, _Traits>::~basic_streambuf()
+{
+}
+
+template <class _CharT, class _Traits>
+basic_streambuf<_CharT, _Traits>::basic_streambuf()
+    : __binp_(nullptr),
+      __ninp_(nullptr),
+      __einp_(nullptr),
+      __bout_(nullptr),
+      __nout_(nullptr),
+      __eout_(nullptr)
+{
+}
+
+template <class _CharT, class _Traits>
+basic_streambuf<_CharT, _Traits>::basic_streambuf(const basic_streambuf& __sb)
+    : __loc_(__sb.__loc_),
+      __binp_(__sb.__binp_),
+      __ninp_(__sb.__ninp_),
+      __einp_(__sb.__einp_),
+      __bout_(__sb.__bout_),
+      __nout_(__sb.__nout_),
+      __eout_(__sb.__eout_)
+{
+}
+
+template <class _CharT, class _Traits>
+basic_streambuf<_CharT, _Traits>&
+basic_streambuf<_CharT, _Traits>::operator=(const basic_streambuf& __sb)
+{
+    __loc_ = __sb.__loc_;
+    __binp_ = __sb.__binp_;
+    __ninp_ = __sb.__ninp_;
+    __einp_ = __sb.__einp_;
+    __bout_ = __sb.__bout_;
+    __nout_ = __sb.__nout_;
+    __eout_ = __sb.__eout_;
+    return *this;
+}
+
+template <class _CharT, class _Traits>
+void
+basic_streambuf<_CharT, _Traits>::swap(basic_streambuf& __sb)
+{
+    _VSTD::swap(__loc_, __sb.__loc_);
+    _VSTD::swap(__binp_, __sb.__binp_);
+    _VSTD::swap(__ninp_, __sb.__ninp_);
+    _VSTD::swap(__einp_, __sb.__einp_);
+    _VSTD::swap(__bout_, __sb.__bout_);
+    _VSTD::swap(__nout_, __sb.__nout_);
+    _VSTD::swap(__eout_, __sb.__eout_);
+}
+
+template <class _CharT, class _Traits>
+void
+basic_streambuf<_CharT, _Traits>::imbue(const locale&)
+{
+}
+
+template <class _CharT, class _Traits>
+basic_streambuf<_CharT, _Traits>*
+basic_streambuf<_CharT, _Traits>::setbuf(char_type*, streamsize)
+{
+    return this;
+}
+
+template <class _CharT, class _Traits>
+typename basic_streambuf<_CharT, _Traits>::pos_type
+basic_streambuf<_CharT, _Traits>::seekoff(off_type, ios_base::seekdir,
+                                          ios_base::openmode)
+{
+    return pos_type(off_type(-1));
+}
+
+template <class _CharT, class _Traits>
+typename basic_streambuf<_CharT, _Traits>::pos_type
+basic_streambuf<_CharT, _Traits>::seekpos(pos_type, ios_base::openmode)
+{
+    return pos_type(off_type(-1));
+}
+
+template <class _CharT, class _Traits>
+int
+basic_streambuf<_CharT, _Traits>::sync()
+{
+    return 0;
+}
+
+template <class _CharT, class _Traits>
+streamsize
+basic_streambuf<_CharT, _Traits>::showmanyc()
+{
+    return 0;
+}
+
+template <class _CharT, class _Traits>
+streamsize
+basic_streambuf<_CharT, _Traits>::xsgetn(char_type* __s, streamsize __n)
+{
+    const int_type __eof = traits_type::eof();
+    int_type __c;
+    streamsize __i = 0;
+    while(__i < __n)
+    {
+        if (__ninp_ < __einp_)
+        {
+            const streamsize __len = _VSTD::min(static_cast<streamsize>(INT_MAX),
+                                _VSTD::min(__einp_ - __ninp_, __n - __i));
+            traits_type::copy(__s, __ninp_, __len);
+            __s +=  __len;
+            __i +=  __len;
+            this->gbump(__len);
+        }
+        else if ((__c = uflow()) != __eof)
+        {
+            *__s = traits_type::to_char_type(__c);
+            ++__s;
+            ++__i;
+        }
+        else
+            break;
+    }
+    return __i;
+}
+
+template <class _CharT, class _Traits>
+typename basic_streambuf<_CharT, _Traits>::int_type
+basic_streambuf<_CharT, _Traits>::underflow()
+{
+    return traits_type::eof();
+}
+
+template <class _CharT, class _Traits>
+typename basic_streambuf<_CharT, _Traits>::int_type
+basic_streambuf<_CharT, _Traits>::uflow()
+{
+    if (underflow() == traits_type::eof())
+        return traits_type::eof();
+    return traits_type::to_int_type(*__ninp_++);
+}
+
+template <class _CharT, class _Traits>
+typename basic_streambuf<_CharT, _Traits>::int_type
+basic_streambuf<_CharT, _Traits>::pbackfail(int_type)
+{
+    return traits_type::eof();
+}
+
+template <class _CharT, class _Traits>
+streamsize
+basic_streambuf<_CharT, _Traits>::xsputn(const char_type* __s, streamsize __n)
+{
+    streamsize __i = 0;
+    int_type __eof = traits_type::eof();
+    while( __i < __n)
+    {
+        if (__nout_ >= __eout_)
+        {
+            if (overflow(traits_type::to_int_type(*__s)) == __eof)
+                break;
+            ++__s;
+            ++__i;
+        }
+        else
+        {
+            streamsize __chunk_size = _VSTD::min(__eout_ - __nout_, __n - __i);
+            traits_type::copy(__nout_, __s, __chunk_size);
+            __nout_ += __chunk_size;
+            __s     += __chunk_size;
+            __i     += __chunk_size;
+        }
+    }
+    return __i;
+}
+
+template <class _CharT, class _Traits>
+typename basic_streambuf<_CharT, _Traits>::int_type
+basic_streambuf<_CharT, _Traits>::overflow(int_type)
+{
+    return traits_type::eof();
+}
+
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_streambuf<char>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_streambuf<wchar_t>)
+
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ios<char>)
+_LIBCPP_EXTERN_TEMPLATE(class _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS basic_ios<wchar_t>)
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_STREAMBUF
diff --git a/contrib/libs/cxxsupp/libcxx/include/string b/contrib/libs/cxxsupp/libcxx/include/string
new file mode 100644
index 00000000000..4f3309fea9c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/string
@@ -0,0 +1,4618 @@
+// -*- C++ -*-
+//===--------------------------- string -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_STRING
+#define _LIBCPP_STRING
+
+/*
+    string synopsis
+
+namespace std
+{
+
+template <class stateT>
+class fpos
+{
+private:
+    stateT st;
+public:
+    fpos(streamoff = streamoff());
+
+    operator streamoff() const;
+
+    stateT state() const;
+    void state(stateT);
+
+    fpos& operator+=(streamoff);
+    fpos  operator+ (streamoff) const;
+    fpos& operator-=(streamoff);
+    fpos  operator- (streamoff) const;
+};
+
+template <class stateT> streamoff operator-(const fpos<stateT>& x, const fpos<stateT>& y);
+
+template <class stateT> bool operator==(const fpos<stateT>& x, const fpos<stateT>& y);
+template <class stateT> bool operator!=(const fpos<stateT>& x, const fpos<stateT>& y);
+
+template <class charT>
+struct char_traits
+{
+    typedef charT     char_type;
+    typedef ...       int_type;
+    typedef streamoff off_type;
+    typedef streampos pos_type;
+    typedef mbstate_t state_type;
+
+    static void assign(char_type& c1, const char_type& c2) noexcept;
+    static constexpr bool eq(char_type c1, char_type c2) noexcept;
+    static constexpr bool lt(char_type c1, char_type c2) noexcept;
+
+    static int              compare(const char_type* s1, const char_type* s2, size_t n);
+    static size_t           length(const char_type* s);
+    static const char_type* find(const char_type* s, size_t n, const char_type& a);
+    static char_type*       move(char_type* s1, const char_type* s2, size_t n);
+    static char_type*       copy(char_type* s1, const char_type* s2, size_t n);
+    static char_type*       assign(char_type* s, size_t n, char_type a);
+
+    static constexpr int_type  not_eof(int_type c) noexcept;
+    static constexpr char_type to_char_type(int_type c) noexcept;
+    static constexpr int_type  to_int_type(char_type c) noexcept;
+    static constexpr bool      eq_int_type(int_type c1, int_type c2) noexcept;
+    static constexpr int_type  eof() noexcept;
+};
+
+template <> struct char_traits<char>;
+template <> struct char_traits<wchar_t>;
+template <> struct char_traits<char8_t>;  // C++20
+template <> struct char_traits<char16_t>;
+template <> struct char_traits<char32_t>;
+
+template<class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
+class basic_string
+{
+public:
+// types:
+    typedef traits traits_type;
+    typedef typename traits_type::char_type value_type;
+    typedef Allocator allocator_type;
+    typedef typename allocator_type::size_type size_type;
+    typedef typename allocator_type::difference_type difference_type;
+    typedef typename allocator_type::reference reference;
+    typedef typename allocator_type::const_reference const_reference;
+    typedef typename allocator_type::pointer pointer;
+    typedef typename allocator_type::const_pointer const_pointer;
+    typedef implementation-defined iterator;
+    typedef implementation-defined const_iterator;
+    typedef std::reverse_iterator<iterator> reverse_iterator;
+    typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+
+    static const size_type npos = -1;
+
+    basic_string()
+        noexcept(is_nothrow_default_constructible<allocator_type>::value);
+    explicit basic_string(const allocator_type& a);
+    basic_string(const basic_string& str);
+    basic_string(basic_string&& str)
+        noexcept(is_nothrow_move_constructible<allocator_type>::value);
+    basic_string(const basic_string& str, size_type pos,
+                 const allocator_type& a = allocator_type());
+    basic_string(const basic_string& str, size_type pos, size_type n,
+                 const Allocator& a = Allocator());
+    template<class T>
+        basic_string(const T& t, size_type pos, size_type n, const Allocator& a = Allocator()); // C++17
+    template <class T>
+        explicit basic_string(const T& t, const Allocator& a = Allocator()); // C++17
+    basic_string(const value_type* s, const allocator_type& a = allocator_type());
+    basic_string(const value_type* s, size_type n, const allocator_type& a = allocator_type());
+    basic_string(nullptr_t) = delete; // C++2b
+    basic_string(size_type n, value_type c, const allocator_type& a = allocator_type());
+    template<class InputIterator>
+        basic_string(InputIterator begin, InputIterator end,
+                     const allocator_type& a = allocator_type());
+    basic_string(initializer_list<value_type>, const Allocator& = Allocator());
+    basic_string(const basic_string&, const Allocator&);
+    basic_string(basic_string&&, const Allocator&);
+
+    ~basic_string();
+
+    operator basic_string_view<charT, traits>() const noexcept;
+
+    basic_string& operator=(const basic_string& str);
+    template <class T>
+        basic_string& operator=(const T& t); // C++17
+    basic_string& operator=(basic_string&& str)
+        noexcept(
+             allocator_type::propagate_on_container_move_assignment::value ||
+             allocator_type::is_always_equal::value ); // C++17
+    basic_string& operator=(const value_type* s);
+    basic_string& operator=(nullptr_t) = delete; // C++2b
+    basic_string& operator=(value_type c);
+    basic_string& operator=(initializer_list<value_type>);
+
+    iterator       begin() noexcept;
+    const_iterator begin() const noexcept;
+    iterator       end() noexcept;
+    const_iterator end() const noexcept;
+
+    reverse_iterator       rbegin() noexcept;
+    const_reverse_iterator rbegin() const noexcept;
+    reverse_iterator       rend() noexcept;
+    const_reverse_iterator rend() const noexcept;
+
+    const_iterator         cbegin() const noexcept;
+    const_iterator         cend() const noexcept;
+    const_reverse_iterator crbegin() const noexcept;
+    const_reverse_iterator crend() const noexcept;
+
+    size_type size() const noexcept;
+    size_type length() const noexcept;
+    size_type max_size() const noexcept;
+    size_type capacity() const noexcept;
+
+    void resize(size_type n, value_type c);
+    void resize(size_type n);
+
+    void reserve(size_type res_arg);
+    void reserve(); // deprecated in C++20
+    void shrink_to_fit();
+    void clear() noexcept;
+    bool empty() const noexcept;
+
+    const_reference operator[](size_type pos) const;
+    reference       operator[](size_type pos);
+
+    const_reference at(size_type n) const;
+    reference       at(size_type n);
+
+    basic_string& operator+=(const basic_string& str);
+    template <class T>
+        basic_string& operator+=(const T& t);              // C++17
+    basic_string& operator+=(const value_type* s);
+    basic_string& operator+=(value_type c);
+    basic_string& operator+=(initializer_list<value_type>);
+
+    basic_string& append(const basic_string& str);
+    template <class T>
+        basic_string& append(const T& t);                 // C++17
+    basic_string& append(const basic_string& str, size_type pos, size_type n=npos); //C++14
+    template <class T>
+        basic_string& append(const T& t, size_type pos, size_type n=npos); // C++17
+    basic_string& append(const value_type* s, size_type n);
+    basic_string& append(const value_type* s);
+    basic_string& append(size_type n, value_type c);
+    template<class InputIterator>
+        basic_string& append(InputIterator first, InputIterator last);
+    basic_string& append(initializer_list<value_type>);
+
+    void push_back(value_type c);
+    void pop_back();
+    reference       front();
+    const_reference front() const;
+    reference       back();
+    const_reference back() const;
+
+    basic_string& assign(const basic_string& str);
+    template <class T>
+        basic_string& assign(const T& t);  // C++17
+    basic_string& assign(basic_string&& str);
+    basic_string& assign(const basic_string& str, size_type pos, size_type n=npos); // C++14
+    template <class T>
+        basic_string& assign(const T& t, size_type pos, size_type n=npos); // C++17
+    basic_string& assign(const value_type* s, size_type n);
+    basic_string& assign(const value_type* s);
+    basic_string& assign(size_type n, value_type c);
+    template<class InputIterator>
+        basic_string& assign(InputIterator first, InputIterator last);
+    basic_string& assign(initializer_list<value_type>);
+
+    basic_string& insert(size_type pos1, const basic_string& str);
+    template <class T>
+        basic_string& insert(size_type pos1, const T& t);
+    basic_string& insert(size_type pos1, const basic_string& str,
+                         size_type pos2, size_type n);
+    template <class T>
+        basic_string& insert(size_type pos1, const T& t, size_type pos2, size_type n); // C++17
+    basic_string& insert(size_type pos, const value_type* s, size_type n=npos); //C++14
+    basic_string& insert(size_type pos, const value_type* s);
+    basic_string& insert(size_type pos, size_type n, value_type c);
+    iterator      insert(const_iterator p, value_type c);
+    iterator      insert(const_iterator p, size_type n, value_type c);
+    template<class InputIterator>
+        iterator insert(const_iterator p, InputIterator first, InputIterator last);
+    iterator      insert(const_iterator p, initializer_list<value_type>);
+
+    basic_string& erase(size_type pos = 0, size_type n = npos);
+    iterator      erase(const_iterator position);
+    iterator      erase(const_iterator first, const_iterator last);
+
+    basic_string& replace(size_type pos1, size_type n1, const basic_string& str);
+    template <class T>
+    basic_string& replace(size_type pos1, size_type n1, const T& t);  // C++17
+    basic_string& replace(size_type pos1, size_type n1, const basic_string& str,
+                          size_type pos2, size_type n2=npos); // C++14
+    template <class T>
+        basic_string& replace(size_type pos1, size_type n1, const T& t,
+                              size_type pos2, size_type n); // C++17
+    basic_string& replace(size_type pos, size_type n1, const value_type* s, size_type n2);
+    basic_string& replace(size_type pos, size_type n1, const value_type* s);
+    basic_string& replace(size_type pos, size_type n1, size_type n2, value_type c);
+    basic_string& replace(const_iterator i1, const_iterator i2, const basic_string& str);
+    template <class T>
+        basic_string& replace(const_iterator i1, const_iterator i2, const T& t);  // C++17
+    basic_string& replace(const_iterator i1, const_iterator i2, const value_type* s, size_type n);
+    basic_string& replace(const_iterator i1, const_iterator i2, const value_type* s);
+    basic_string& replace(const_iterator i1, const_iterator i2, size_type n, value_type c);
+    template<class InputIterator>
+        basic_string& replace(const_iterator i1, const_iterator i2, InputIterator j1, InputIterator j2);
+    basic_string& replace(const_iterator i1, const_iterator i2, initializer_list<value_type>);
+
+    size_type copy(value_type* s, size_type n, size_type pos = 0) const;
+    basic_string substr(size_type pos = 0, size_type n = npos) const;
+
+    void swap(basic_string& str)
+        noexcept(allocator_traits<allocator_type>::propagate_on_container_swap::value ||
+                 allocator_traits<allocator_type>::is_always_equal::value);  // C++17
+
+    const value_type* c_str() const noexcept;
+    const value_type* data() const noexcept;
+          value_type* data()       noexcept;   // C++17
+
+    allocator_type get_allocator() const noexcept;
+
+    size_type find(const basic_string& str, size_type pos = 0) const noexcept;
+    template <class T>
+        size_type find(const T& t, size_type pos = 0) const noexcept; // C++17, noexcept as an extension
+    size_type find(const value_type* s, size_type pos, size_type n) const noexcept;
+    size_type find(const value_type* s, size_type pos = 0) const noexcept;
+    size_type find(value_type c, size_type pos = 0) const noexcept;
+
+    size_type rfind(const basic_string& str, size_type pos = npos) const noexcept;
+    template <class T>
+        size_type rfind(const T& t, size_type pos = npos) const noexcept; // C++17, noexcept as an extension
+    size_type rfind(const value_type* s, size_type pos, size_type n) const noexcept;
+    size_type rfind(const value_type* s, size_type pos = npos) const noexcept;
+    size_type rfind(value_type c, size_type pos = npos) const noexcept;
+
+    size_type find_first_of(const basic_string& str, size_type pos = 0) const noexcept;
+    template <class T>
+        size_type find_first_of(const T& t, size_type pos = 0) const noexcept; // C++17, noexcept as an extension
+    size_type find_first_of(const value_type* s, size_type pos, size_type n) const noexcept;
+    size_type find_first_of(const value_type* s, size_type pos = 0) const noexcept;
+    size_type find_first_of(value_type c, size_type pos = 0) const noexcept;
+
+    size_type find_last_of(const basic_string& str, size_type pos = npos) const noexcept;
+    template <class T>
+        size_type find_last_of(const T& t, size_type pos = npos) const noexcept noexcept; // C++17, noexcept as an extension
+    size_type find_last_of(const value_type* s, size_type pos, size_type n) const noexcept;
+    size_type find_last_of(const value_type* s, size_type pos = npos) const noexcept;
+    size_type find_last_of(value_type c, size_type pos = npos) const noexcept;
+
+    size_type find_first_not_of(const basic_string& str, size_type pos = 0) const noexcept;
+    template <class T>
+        size_type find_first_not_of(const T& t, size_type pos = 0) const noexcept; // C++17, noexcept as an extension
+    size_type find_first_not_of(const value_type* s, size_type pos, size_type n) const noexcept;
+    size_type find_first_not_of(const value_type* s, size_type pos = 0) const noexcept;
+    size_type find_first_not_of(value_type c, size_type pos = 0) const noexcept;
+
+    size_type find_last_not_of(const basic_string& str, size_type pos = npos) const noexcept;
+    template <class T>
+        size_type find_last_not_of(const T& t, size_type pos = npos) const noexcept; // C++17, noexcept as an extension
+    size_type find_last_not_of(const value_type* s, size_type pos, size_type n) const noexcept;
+    size_type find_last_not_of(const value_type* s, size_type pos = npos) const noexcept;
+    size_type find_last_not_of(value_type c, size_type pos = npos) const noexcept;
+
+    int compare(const basic_string& str) const noexcept;
+    template <class T>
+        int compare(const T& t) const noexcept;  // C++17, noexcept as an extension
+    int compare(size_type pos1, size_type n1, const basic_string& str) const;
+    template <class T>
+        int compare(size_type pos1, size_type n1, const T& t) const;  // C++17
+    int compare(size_type pos1, size_type n1, const basic_string& str,
+                size_type pos2, size_type n2=npos) const; // C++14
+    template <class T>
+        int compare(size_type pos1, size_type n1, const T& t,
+                    size_type pos2, size_type n2=npos) const; // C++17
+    int compare(const value_type* s) const noexcept;
+    int compare(size_type pos1, size_type n1, const value_type* s) const;
+    int compare(size_type pos1, size_type n1, const value_type* s, size_type n2) const;
+
+    bool starts_with(basic_string_view<charT, traits> sv) const noexcept; // C++20
+    bool starts_with(charT c) const noexcept;                             // C++20
+    bool starts_with(const charT* s) const;                               // C++20
+    bool ends_with(basic_string_view<charT, traits> sv) const noexcept;   // C++20
+    bool ends_with(charT c) const noexcept;                               // C++20
+    bool ends_with(const charT* s) const;                                 // C++20
+
+    constexpr bool contains(basic_string_view<charT, traits> sv) const noexcept; // C++2b
+    constexpr bool contains(charT c) const noexcept;                             // C++2b
+    constexpr bool contains(const charT* s) const;                               // C++2b
+
+    bool __invariants() const;
+};
+
+template<class InputIterator,
+         class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
+basic_string(InputIterator, InputIterator, Allocator = Allocator())
+   -> basic_string<typename iterator_traits<InputIterator>::value_type,
+                  char_traits<typename iterator_traits<InputIterator>::value_type>,
+                  Allocator>;   // C++17
+
+template<class charT, class traits, class Allocator>
+basic_string<charT, traits, Allocator>
+operator+(const basic_string<charT, traits, Allocator>& lhs,
+          const basic_string<charT, traits, Allocator>& rhs);
+
+template<class charT, class traits, class Allocator>
+basic_string<charT, traits, Allocator>
+operator+(const charT* lhs , const basic_string<charT,traits,Allocator>&rhs);
+
+template<class charT, class traits, class Allocator>
+basic_string<charT, traits, Allocator>
+operator+(charT lhs, const basic_string<charT,traits,Allocator>& rhs);
+
+template<class charT, class traits, class Allocator>
+basic_string<charT, traits, Allocator>
+operator+(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs);
+
+template<class charT, class traits, class Allocator>
+basic_string<charT, traits, Allocator>
+operator+(const basic_string<charT, traits, Allocator>& lhs, charT rhs);
+
+template<class charT, class traits, class Allocator>
+bool operator==(const basic_string<charT, traits, Allocator>& lhs,
+                const basic_string<charT, traits, Allocator>& rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator==(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator==(const basic_string<charT,traits,Allocator>& lhs, const charT* rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator!=(const basic_string<charT,traits,Allocator>& lhs,
+                const basic_string<charT, traits, Allocator>& rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator!=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator!=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator< (const basic_string<charT, traits, Allocator>& lhs,
+                const basic_string<charT, traits, Allocator>& rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator< (const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator< (const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator> (const basic_string<charT, traits, Allocator>& lhs,
+                const basic_string<charT, traits, Allocator>& rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator> (const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator> (const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator<=(const basic_string<charT, traits, Allocator>& lhs,
+                const basic_string<charT, traits, Allocator>& rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator<=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator<=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator>=(const basic_string<charT, traits, Allocator>& lhs,
+                const basic_string<charT, traits, Allocator>& rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator>=(const basic_string<charT, traits, Allocator>& lhs, const charT* rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+bool operator>=(const charT* lhs, const basic_string<charT, traits, Allocator>& rhs) noexcept;
+
+template<class charT, class traits, class Allocator>
+void swap(basic_string<charT, traits, Allocator>& lhs,
+          basic_string<charT, traits, Allocator>& rhs)
+            noexcept(noexcept(lhs.swap(rhs)));
+
+template<class charT, class traits, class Allocator>
+basic_istream<charT, traits>&
+operator>>(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str);
+
+template<class charT, class traits, class Allocator>
+basic_ostream<charT, traits>&
+operator<<(basic_ostream<charT, traits>& os, const basic_string<charT, traits, Allocator>& str);
+
+template<class charT, class traits, class Allocator>
+basic_istream<charT, traits>&
+getline(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str,
+        charT delim);
+
+template<class charT, class traits, class Allocator>
+basic_istream<charT, traits>&
+getline(basic_istream<charT, traits>& is, basic_string<charT, traits, Allocator>& str);
+
+template<class charT, class traits, class Allocator, class U>
+typename basic_string<charT, traits, Allocator>::size_type
+erase(basic_string<charT, traits, Allocator>& c, const U& value);    // C++20
+template<class charT, class traits, class Allocator, class Predicate>
+typename basic_string<charT, traits, Allocator>::size_type
+erase_if(basic_string<charT, traits, Allocator>& c, Predicate pred); // C++20
+
+typedef basic_string<char>    string;
+typedef basic_string<wchar_t> wstring;
+typedef basic_string<char8_t> u8string; // C++20
+typedef basic_string<char16_t> u16string;
+typedef basic_string<char32_t> u32string;
+
+int                stoi  (const string& str, size_t* idx = nullptr, int base = 10);
+long               stol  (const string& str, size_t* idx = nullptr, int base = 10);
+unsigned long      stoul (const string& str, size_t* idx = nullptr, int base = 10);
+long long          stoll (const string& str, size_t* idx = nullptr, int base = 10);
+unsigned long long stoull(const string& str, size_t* idx = nullptr, int base = 10);
+
+float       stof (const string& str, size_t* idx = nullptr);
+double      stod (const string& str, size_t* idx = nullptr);
+long double stold(const string& str, size_t* idx = nullptr);
+
+string to_string(int val);
+string to_string(unsigned val);
+string to_string(long val);
+string to_string(unsigned long val);
+string to_string(long long val);
+string to_string(unsigned long long val);
+string to_string(float val);
+string to_string(double val);
+string to_string(long double val);
+
+int                stoi  (const wstring& str, size_t* idx = nullptr, int base = 10);
+long               stol  (const wstring& str, size_t* idx = nullptr, int base = 10);
+unsigned long      stoul (const wstring& str, size_t* idx = nullptr, int base = 10);
+long long          stoll (const wstring& str, size_t* idx = nullptr, int base = 10);
+unsigned long long stoull(const wstring& str, size_t* idx = nullptr, int base = 10);
+
+float       stof (const wstring& str, size_t* idx = nullptr);
+double      stod (const wstring& str, size_t* idx = nullptr);
+long double stold(const wstring& str, size_t* idx = nullptr);
+
+wstring to_wstring(int val);
+wstring to_wstring(unsigned val);
+wstring to_wstring(long val);
+wstring to_wstring(unsigned long val);
+wstring to_wstring(long long val);
+wstring to_wstring(unsigned long long val);
+wstring to_wstring(float val);
+wstring to_wstring(double val);
+wstring to_wstring(long double val);
+
+template <> struct hash<string>;
+template <> struct hash<u8string>; // C++20
+template <> struct hash<u16string>;
+template <> struct hash<u32string>;
+template <> struct hash<wstring>;
+
+basic_string<char>     operator "" s( const char *str,     size_t len ); // C++14
+basic_string<wchar_t>  operator "" s( const wchar_t *str,  size_t len ); // C++14
+basic_string<char8_t>  operator "" s( const char8_t *str,  size_t len ); // C++20
+basic_string<char16_t> operator "" s( const char16_t *str, size_t len ); // C++14
+basic_string<char32_t> operator "" s( const char32_t *str, size_t len ); // C++14
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__functional_base>
+#include <__iterator/wrap_iter.h>
+#include <algorithm>
+#include <compare>
+#include <cstdio>  // EOF
+#include <cstdlib>
+#include <cstring>
+#include <initializer_list>
+#include <iosfwd>
+#include <iterator>
+#include <memory>
+#include <stdexcept>
+#include <string_view>
+#include <type_traits>
+#include <utility>
+#include <version>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#   include <cwchar>
+#endif
+
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+# include <cstdint>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4455 )
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// fpos
+
+template <class _StateT>
+class _LIBCPP_TEMPLATE_VIS fpos
+{
+private:
+    _StateT __st_;
+    streamoff __off_;
+public:
+    _LIBCPP_INLINE_VISIBILITY fpos(streamoff __off = streamoff()) : __st_(), __off_(__off) {}
+
+    _LIBCPP_INLINE_VISIBILITY operator streamoff() const {return __off_;}
+
+    _LIBCPP_INLINE_VISIBILITY _StateT state() const {return __st_;}
+    _LIBCPP_INLINE_VISIBILITY void state(_StateT __st) {__st_ = __st;}
+
+    _LIBCPP_INLINE_VISIBILITY fpos& operator+=(streamoff __off) {__off_ += __off; return *this;}
+    _LIBCPP_INLINE_VISIBILITY fpos  operator+ (streamoff __off) const {fpos __t(*this); __t += __off; return __t;}
+    _LIBCPP_INLINE_VISIBILITY fpos& operator-=(streamoff __off) {__off_ -= __off; return *this;}
+    _LIBCPP_INLINE_VISIBILITY fpos  operator- (streamoff __off) const {fpos __t(*this); __t -= __off; return __t;}
+};
+
+template <class _StateT>
+inline _LIBCPP_INLINE_VISIBILITY
+streamoff operator-(const fpos<_StateT>& __x, const fpos<_StateT>& __y)
+    {return streamoff(__x) - streamoff(__y);}
+
+template <class _StateT>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator==(const fpos<_StateT>& __x, const fpos<_StateT>& __y)
+    {return streamoff(__x) == streamoff(__y);}
+
+template <class _StateT>
+inline _LIBCPP_INLINE_VISIBILITY
+bool operator!=(const fpos<_StateT>& __x, const fpos<_StateT>& __y)
+    {return streamoff(__x) != streamoff(__y);}
+
+// basic_string
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __x,
+          const basic_string<_CharT, _Traits, _Allocator>& __y);
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const _CharT* __x, const basic_string<_CharT,_Traits,_Allocator>& __y);
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>
+operator+(_CharT __x, const basic_string<_CharT,_Traits,_Allocator>& __y);
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __x, const _CharT* __y);
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __x, _CharT __y);
+
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS string operator+<char, char_traits<char>, allocator<char> >(char const*, string const&))
+
+template <bool>
+struct __basic_string_common;
+
+template <>
+struct __basic_string_common<true> {
+    // Both are defined in string.cpp
+    _LIBCPP_NORETURN _LIBCPP_EXPORTED_FROM_ABI void __throw_length_error() const;
+    _LIBCPP_NORETURN _LIBCPP_EXPORTED_FROM_ABI void __throw_out_of_range() const;
+};
+
+template <class _Iter>
+struct __string_is_trivial_iterator : public false_type {};
+
+template <class _Tp>
+struct __string_is_trivial_iterator<_Tp*>
+    : public is_arithmetic<_Tp> {};
+
+template <class _Iter>
+struct __string_is_trivial_iterator<__wrap_iter<_Iter> >
+    : public __string_is_trivial_iterator<_Iter> {};
+
+template <class _CharT, class _Traits, class _Tp>
+struct __can_be_converted_to_string_view : public _BoolConstant<
+      is_convertible<const _Tp&, basic_string_view<_CharT, _Traits> >::value &&
+     !is_convertible<const _Tp&, const _CharT*>::value
+    > {};
+
+#ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+
+template <class _CharT, size_t = sizeof(_CharT)>
+struct __padding
+{
+    unsigned char __xx[sizeof(_CharT)-1];
+};
+
+template <class _CharT>
+struct __padding<_CharT, 1>
+{
+};
+
+#endif // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+typedef basic_string<char8_t> u8string;
+#endif
+
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+typedef basic_string<char16_t> u16string;
+typedef basic_string<char32_t> u32string;
+#endif
+
+template<class _CharT, class _Traits, class _Allocator>
+class
+    _LIBCPP_TEMPLATE_VIS
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+    _LIBCPP_PREFERRED_NAME(u8string)
+#endif
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+    _LIBCPP_PREFERRED_NAME(u16string)
+    _LIBCPP_PREFERRED_NAME(u32string)
+#endif
+    basic_string
+    : private __basic_string_common<true> // This base class is historical, but it needs to remain for ABI compatibility
+{
+	static_assert(sizeof(_CharT) <= 4, "libc++ implementation of std::basic_string does not support extra-wide character types");
+public:
+    typedef basic_string                                 __self;
+    typedef basic_string_view<_CharT, _Traits>           __self_view;
+    typedef _Traits                                      traits_type;
+    typedef _CharT                                       value_type;
+    typedef _Allocator                                   allocator_type;
+    typedef allocator_traits<allocator_type>             __alloc_traits;
+    typedef typename __alloc_traits::size_type           size_type;
+    typedef typename __alloc_traits::difference_type     difference_type;
+    typedef value_type&                                  reference;
+    typedef const value_type&                            const_reference;
+    typedef typename __alloc_traits::pointer             pointer;
+    typedef typename __alloc_traits::const_pointer       const_pointer;
+
+    static_assert((!is_array<value_type>::value), "Character type of basic_string must not be an array");
+    static_assert(( is_standard_layout<value_type>::value), "Character type of basic_string must be standard-layout");
+    static_assert(( is_trivial<value_type>::value), "Character type of basic_string must be trivial");
+    static_assert(( is_same<_CharT, typename traits_type::char_type>::value),
+                  "traits_type::char_type must be the same type as CharT");
+    static_assert(( is_same<typename allocator_type::value_type, value_type>::value),
+                  "Allocator::value_type must be same type as value_type");
+
+#if _YNDX_LIBCPP_MAKE_STRING_ITERATOR_POINTERS == 1
+    typedef pointer                                      iterator;
+    typedef const_pointer                                const_iterator;
+#else
+    typedef __wrap_iter<pointer>                         iterator;
+    typedef __wrap_iter<const_pointer>                   const_iterator;
+#endif
+    typedef _VSTD::reverse_iterator<iterator>             reverse_iterator;
+    typedef _VSTD::reverse_iterator<const_iterator>       const_reverse_iterator;
+
+private:
+
+#ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+
+    struct __long
+    {
+        pointer   __data_;
+        size_type __size_;
+        size_type __cap_;
+    };
+
+#ifdef _LIBCPP_BIG_ENDIAN
+    static const size_type __short_mask = 0x01;
+    static const size_type __long_mask  = 0x1ul;
+#else  // _LIBCPP_BIG_ENDIAN
+    static const size_type __short_mask = 0x80;
+    static const size_type __long_mask  = ~(size_type(~0) >> 1);
+#endif // _LIBCPP_BIG_ENDIAN
+
+    enum {__min_cap = (sizeof(__long) - 1)/sizeof(value_type) > 2 ?
+                      (sizeof(__long) - 1)/sizeof(value_type) : 2};
+
+    struct __short
+    {
+        value_type __data_[__min_cap];
+        struct
+            : __padding<value_type>
+        {
+            unsigned char __size_;
+        };
+    };
+
+#else
+
+    struct __long
+    {
+        size_type __cap_;
+        size_type __size_;
+        pointer   __data_;
+    };
+
+#ifdef _LIBCPP_BIG_ENDIAN
+    static const size_type __short_mask = 0x80;
+    static const size_type __long_mask  = ~(size_type(~0) >> 1);
+#else  // _LIBCPP_BIG_ENDIAN
+    static const size_type __short_mask = 0x01;
+    static const size_type __long_mask  = 0x1ul;
+#endif // _LIBCPP_BIG_ENDIAN
+
+    enum {__min_cap = (sizeof(__long) - 1)/sizeof(value_type) > 2 ?
+                      (sizeof(__long) - 1)/sizeof(value_type) : 2};
+
+    struct __short
+    {
+        union
+        {
+            unsigned char __size_;
+            value_type __lx;
+        };
+        value_type __data_[__min_cap];
+    };
+
+#endif // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+
+    union __ulx{__long __lx; __short __lxx;};
+
+    enum {__n_words = sizeof(__ulx) / sizeof(size_type)};
+
+    struct __raw
+    {
+        size_type __words[__n_words];
+    };
+
+    struct __rep
+    {
+        union
+        {
+            __long  __l;
+            __short __s;
+            __raw   __r;
+        };
+    };
+
+    __compressed_pair<__rep, allocator_type> __r_;
+
+public:
+    _LIBCPP_TEMPLATE_DATA_VIS
+    static const size_type npos = -1;
+
+    _LIBCPP_INLINE_VISIBILITY basic_string()
+        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value);
+
+    _LIBCPP_INLINE_VISIBILITY explicit basic_string(const allocator_type& __a)
+#if _LIBCPP_STD_VER <= 14
+        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value);
+#else
+        _NOEXCEPT;
+#endif
+
+    basic_string(const basic_string& __str);
+    basic_string(const basic_string& __str, const allocator_type& __a);
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string(basic_string&& __str)
+#if _LIBCPP_STD_VER <= 14
+        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value);
+#else
+        _NOEXCEPT;
+#endif
+
+#if _LIBCPP_STD_VER > 20
+    basic_string(nullptr_t) = delete;
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string(basic_string&& __str, const allocator_type& __a);
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    basic_string(nullptr_t) = delete;
+
+    template <class = __enable_if_t<__is_allocator<_Allocator>::value, nullptr_t> >
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string(const _CharT* __s) : __r_(__default_init_tag(), __default_init_tag()) {
+      _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*) detected nullptr");
+      __init(__s, traits_type::length(__s));
+#   if _LIBCPP_DEBUG_LEVEL == 2
+      __get_db()->__insert_c(this);
+#   endif
+    }
+
+    template <class = __enable_if_t<__is_allocator<_Allocator>::value, nullptr_t> >
+        _LIBCPP_INLINE_VISIBILITY
+        basic_string(const _CharT* __s, const _Allocator& __a);
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    basic_string(nullptr_t, size_t) = delete;
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string(const _CharT* __s, size_type __n);
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    basic_string(nullptr_t, size_t, const _Allocator&) = delete;
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string(const _CharT* __s, size_type __n, const _Allocator& __a);
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string(size_type __n, _CharT __c);
+
+    template <class = __enable_if_t<__is_allocator<_Allocator>::value, nullptr_t> >
+        _LIBCPP_INLINE_VISIBILITY
+        basic_string(size_type __n, _CharT __c, const _Allocator& __a);
+
+    basic_string(const basic_string& __str, size_type __pos, size_type __n,
+                 const _Allocator& __a = _Allocator());
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string(const basic_string& __str, size_type __pos,
+                 const _Allocator& __a = _Allocator());
+
+    template<class _Tp, class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value && !__is_same_uncvref<_Tp, basic_string>::value> >
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        basic_string(const _Tp& __t, size_type __pos, size_type __n,
+                     const allocator_type& __a = allocator_type());
+
+    template<class _Tp, class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value &&
+                                          !__is_same_uncvref<_Tp, basic_string>::value> >
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        explicit basic_string(const _Tp& __t);
+
+    template<class _Tp, class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value && !__is_same_uncvref<_Tp, basic_string>::value> >
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        explicit basic_string(const _Tp& __t, const allocator_type& __a);
+
+    template<class _InputIterator, class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value> >
+        _LIBCPP_INLINE_VISIBILITY
+        basic_string(_InputIterator __first, _InputIterator __last);
+    template<class _InputIterator, class = __enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value> >
+        _LIBCPP_INLINE_VISIBILITY
+        basic_string(_InputIterator __first, _InputIterator __last, const allocator_type& __a);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string(initializer_list<_CharT> __il);
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string(initializer_list<_CharT> __il, const _Allocator& __a);
+#endif // _LIBCPP_CXX03_LANG
+
+    inline ~basic_string();
+
+    _LIBCPP_INLINE_VISIBILITY
+    operator __self_view() const _NOEXCEPT { return __self_view(data(), size()); }
+
+    basic_string& operator=(const basic_string& __str);
+
+    basic_string& operator=(nullptr_t) = delete;
+
+    template <class _Tp, class = __enable_if_t<__can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value && !__is_same_uncvref<_Tp, basic_string>::value> >
+    basic_string& operator=(const _Tp& __t)
+        {__self_view __sv = __t; return assign(__sv);}
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string& operator=(basic_string&& __str)
+        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value));
+     _LIBCPP_INLINE_VISIBILITY
+    basic_string& operator=(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
+#endif
+    _LIBCPP_INLINE_VISIBILITY basic_string& operator=(const value_type* __s) {return assign(__s);}
+#if _LIBCPP_STD_VER > 20
+    basic_string& operator=(nullptr_t) = delete;
+#endif
+    basic_string& operator=(value_type __c);
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    iterator begin() _NOEXCEPT
+        {return iterator(this, __get_pointer());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const _NOEXCEPT
+        {return const_iterator(this, __get_pointer());}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator end() _NOEXCEPT
+        {return iterator(this, __get_pointer() + size());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end() const _NOEXCEPT
+        {return const_iterator(this, __get_pointer() + size());}
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    iterator begin() _NOEXCEPT
+        {return iterator(__get_pointer());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const _NOEXCEPT
+        {return const_iterator(__get_pointer());}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator end() _NOEXCEPT
+        {return iterator(__get_pointer() + size());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end() const _NOEXCEPT
+        {return const_iterator(__get_pointer() + size());}
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_INLINE_VISIBILITY
+    reverse_iterator rbegin() _NOEXCEPT
+        {return reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rbegin() const _NOEXCEPT
+        {return const_reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    reverse_iterator rend() _NOEXCEPT
+        {return reverse_iterator(begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rend() const _NOEXCEPT
+        {return const_reverse_iterator(begin());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin() const _NOEXCEPT
+        {return begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend() const _NOEXCEPT
+        {return end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crbegin() const _NOEXCEPT
+        {return rbegin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crend() const _NOEXCEPT
+        {return rend();}
+
+    _LIBCPP_INLINE_VISIBILITY size_type size() const _NOEXCEPT
+        {return __is_long() ? __get_long_size() : __get_short_size();}
+    _LIBCPP_INLINE_VISIBILITY size_type length() const _NOEXCEPT {return size();}
+    _LIBCPP_INLINE_VISIBILITY size_type max_size() const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY size_type capacity() const _NOEXCEPT
+        {return (__is_long() ? __get_long_cap()
+                             : static_cast<size_type>(__min_cap)) - 1;}
+
+
+#if _YNDX_LIBCXX_ENABLE_STRING_RESIZE_UNINITIALIZED == 1
+    inline void resize_uninitialized(size_type __n)
+    {
+        __resize_default_init(__n);
+    }
+#endif
+
+    void resize(size_type __n, value_type __c);
+    _LIBCPP_INLINE_VISIBILITY void resize(size_type __n) {resize(__n, value_type());}
+
+    void reserve(size_type __requested_capacity);
+    _LIBCPP_INLINE_VISIBILITY void __resize_default_init(size_type __n);
+
+    _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_INLINE_VISIBILITY
+    void reserve() _NOEXCEPT {shrink_to_fit();}
+    _LIBCPP_INLINE_VISIBILITY
+    void shrink_to_fit() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT;
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT {return size() == 0;}
+
+    _LIBCPP_INLINE_VISIBILITY const_reference operator[](size_type __pos) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY reference       operator[](size_type __pos)       _NOEXCEPT;
+
+    const_reference at(size_type __n) const;
+    reference       at(size_type __n);
+
+    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(const basic_string& __str) {return append(__str);}
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
+            && !__is_same_uncvref<_Tp, basic_string >::value,
+            basic_string&
+        >
+                                            operator+=(const _Tp& __t)            {__self_view __sv = __t; return append(__sv);}
+    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(const value_type* __s)     {return append(__s);}
+    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(value_type __c)            {push_back(__c); return *this;}
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY basic_string& operator+=(initializer_list<value_type> __il) {return append(__il);}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string& append(const basic_string& __str);
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t<
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
+            && !__is_same_uncvref<_Tp, basic_string>::value,
+            basic_string&
+        >
+                  append(const _Tp& __t) { __self_view __sv = __t; return append(__sv.data(), __sv.size()); }
+    basic_string& append(const basic_string& __str, size_type __pos, size_type __n=npos);
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
+            && !__is_same_uncvref<_Tp, basic_string>::value,
+            basic_string&
+        >
+                  append(const _Tp& __t, size_type __pos, size_type __n=npos);
+    basic_string& append(const value_type* __s, size_type __n);
+    basic_string& append(const value_type* __s);
+    basic_string& append(size_type __n, value_type __c);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __append_default_init(size_type __n);
+
+    template<class _InputIterator>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __is_exactly_cpp17_input_iterator<_InputIterator>::value,
+            basic_string&
+        >
+    _LIBCPP_INLINE_VISIBILITY
+    append(_InputIterator __first, _InputIterator __last) {
+      const basic_string __temp(__first, __last, __alloc());
+      append(__temp.data(), __temp.size());
+      return *this;
+    }
+    template<class _ForwardIterator>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __is_cpp17_forward_iterator<_ForwardIterator>::value,
+            basic_string&
+        >
+    _LIBCPP_INLINE_VISIBILITY
+    append(_ForwardIterator __first, _ForwardIterator __last);
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string& append(initializer_list<value_type> __il) {return append(__il.begin(), __il.size());}
+#endif // _LIBCPP_CXX03_LANG
+
+    void push_back(value_type __c);
+    _LIBCPP_INLINE_VISIBILITY
+    void pop_back();
+    _LIBCPP_INLINE_VISIBILITY reference       front() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY const_reference front() const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY reference       back() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY const_reference back() const _NOEXCEPT;
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+            basic_string&
+        >
+                 assign(const _Tp & __t) { __self_view __sv = __t; return assign(__sv.data(), __sv.size()); }
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string& assign(const basic_string& __str) { return *this = __str; }
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string& assign(basic_string&& __str)
+        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
+        {*this = _VSTD::move(__str); return *this;}
+#endif
+    basic_string& assign(const basic_string& __str, size_type __pos, size_type __n=npos);
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
+            && !__is_same_uncvref<_Tp, basic_string>::value,
+            basic_string&
+        >
+                  assign(const _Tp & __t, size_type __pos, size_type __n=npos);
+    basic_string& assign(const value_type* __s, size_type __n);
+    basic_string& assign(const value_type* __s);
+    basic_string& assign(size_type __n, value_type __c);
+    template<class _InputIterator>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __is_exactly_cpp17_input_iterator<_InputIterator>::value,
+            basic_string&
+        >
+        assign(_InputIterator __first, _InputIterator __last);
+    template<class _ForwardIterator>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __is_cpp17_forward_iterator<_ForwardIterator>::value,
+            basic_string&
+        >
+        assign(_ForwardIterator __first, _ForwardIterator __last);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string& assign(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string& insert(size_type __pos1, const basic_string& __str);
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+            basic_string&
+        >
+                 insert(size_type __pos1, const _Tp& __t)
+    { __self_view __sv = __t; return insert(__pos1, __sv.data(), __sv.size()); }
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value && !__is_same_uncvref<_Tp, basic_string>::value,
+            basic_string&
+        >
+                  insert(size_type __pos1, const _Tp& __t, size_type __pos2, size_type __n=npos);
+    basic_string& insert(size_type __pos1, const basic_string& __str, size_type __pos2, size_type __n=npos);
+    basic_string& insert(size_type __pos, const value_type* __s, size_type __n);
+    basic_string& insert(size_type __pos, const value_type* __s);
+    basic_string& insert(size_type __pos, size_type __n, value_type __c);
+    iterator      insert(const_iterator __pos, value_type __c);
+    _LIBCPP_INLINE_VISIBILITY
+    iterator      insert(const_iterator __pos, size_type __n, value_type __c);
+    template<class _InputIterator>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __is_exactly_cpp17_input_iterator<_InputIterator>::value,
+            iterator
+        >
+        insert(const_iterator __pos, _InputIterator __first, _InputIterator __last);
+    template<class _ForwardIterator>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __is_cpp17_forward_iterator<_ForwardIterator>::value,
+            iterator
+        >
+        insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __pos, initializer_list<value_type> __il)
+                    {return insert(__pos, __il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+
+    basic_string& erase(size_type __pos = 0, size_type __n = npos);
+    _LIBCPP_INLINE_VISIBILITY
+    iterator      erase(const_iterator __pos);
+    _LIBCPP_INLINE_VISIBILITY
+    iterator      erase(const_iterator __first, const_iterator __last);
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string& replace(size_type __pos1, size_type __n1, const basic_string& __str);
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+            basic_string&
+        >
+                  replace(size_type __pos1, size_type __n1, const _Tp& __t) { __self_view __sv = __t; return replace(__pos1, __n1, __sv.data(), __sv.size()); }
+    basic_string& replace(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2=npos);
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value  && !__is_same_uncvref<_Tp, basic_string>::value,
+            basic_string&
+        >
+                  replace(size_type __pos1, size_type __n1, const _Tp& __t, size_type __pos2, size_type __n2=npos);
+    basic_string& replace(size_type __pos, size_type __n1, const value_type* __s, size_type __n2);
+    basic_string& replace(size_type __pos, size_type __n1, const value_type* __s);
+    basic_string& replace(size_type __pos, size_type __n1, size_type __n2, value_type __c);
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string& replace(const_iterator __i1, const_iterator __i2, const basic_string& __str);
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+            basic_string&
+        >
+                  replace(const_iterator __i1, const_iterator __i2, const _Tp& __t) { __self_view __sv = __t; return replace(__i1 - begin(), __i2 - __i1, __sv); }
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string& replace(const_iterator __i1, const_iterator __i2, const value_type* __s, size_type __n);
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string& replace(const_iterator __i1, const_iterator __i2, const value_type* __s);
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string& replace(const_iterator __i1, const_iterator __i2, size_type __n, value_type __c);
+    template<class _InputIterator>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __is_cpp17_input_iterator<_InputIterator>::value,
+            basic_string&
+        >
+        replace(const_iterator __i1, const_iterator __i2, _InputIterator __j1, _InputIterator __j2);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string& replace(const_iterator __i1, const_iterator __i2, initializer_list<value_type> __il)
+        {return replace(__i1, __i2, __il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+
+    size_type copy(value_type* __s, size_type __n, size_type __pos = 0) const;
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string substr(size_type __pos = 0, size_type __n = npos) const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(basic_string& __str)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT;
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<allocator_type>::value);
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    const value_type* c_str() const _NOEXCEPT {return data();}
+    _LIBCPP_INLINE_VISIBILITY
+    const value_type* data() const _NOEXCEPT  {return _VSTD::__to_address(__get_pointer());}
+#if _LIBCPP_STD_VER > 14 || defined(_LIBCPP_BUILDING_LIBRARY)
+    _LIBCPP_INLINE_VISIBILITY
+    value_type* data()             _NOEXCEPT  {return _VSTD::__to_address(__get_pointer());}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT {return __alloc();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+            size_type
+        >
+              find(const _Tp& __t, size_type __pos = 0) const _NOEXCEPT;
+    size_type find(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
+    size_type find(value_type __c, size_type __pos = 0) const _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type rfind(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+            size_type
+        >
+              rfind(const _Tp& __t, size_type __pos = npos) const _NOEXCEPT;
+    size_type rfind(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    size_type rfind(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
+    size_type rfind(value_type __c, size_type __pos = npos) const _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+            size_type
+        >
+              find_first_of(const _Tp& __t, size_type __pos = 0) const _NOEXCEPT;
+    size_type find_first_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_of(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_of(value_type __c, size_type __pos = 0) const _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+            size_type
+        >
+              find_last_of(const _Tp& __t, size_type __pos = npos) const _NOEXCEPT;
+    size_type find_last_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_of(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_of(value_type __c, size_type __pos = npos) const _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_not_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT;
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+            size_type
+        >
+              find_first_not_of(const _Tp &__t, size_type __pos = 0) const _NOEXCEPT;
+    size_type find_first_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_not_of(const value_type* __s, size_type __pos = 0) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_not_of(value_type __c, size_type __pos = 0) const _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_not_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT;
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+            size_type
+        >
+              find_last_not_of(const _Tp& __t, size_type __pos = npos) const _NOEXCEPT;
+    size_type find_last_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_not_of(const value_type* __s, size_type __pos = npos) const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_not_of(value_type __c, size_type __pos = npos) const _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    int compare(const basic_string& __str) const _NOEXCEPT;
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+            int
+        >
+        compare(const _Tp &__t) const _NOEXCEPT;
+
+    template <class _Tp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+            int
+        >
+         compare(size_type __pos1, size_type __n1, const _Tp& __t) const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    int compare(size_type __pos1, size_type __n1, const basic_string& __str) const;
+    int compare(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2=npos) const;
+
+    template <class _Tp>
+    inline _LIBCPP_INLINE_VISIBILITY
+        __enable_if_t
+        <
+            __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value  && !__is_same_uncvref<_Tp, basic_string>::value,
+            int
+        >
+        compare(size_type __pos1, size_type __n1, const _Tp& __t, size_type __pos2, size_type __n2=npos) const;
+    int compare(const value_type* __s) const _NOEXCEPT;
+    int compare(size_type __pos1, size_type __n1, const value_type* __s) const;
+    int compare(size_type __pos1, size_type __n1, const value_type* __s, size_type __n2) const;
+
+//WARN: disabled std guards in order to allow using these options without switching to new std
+//#if _LIBCPP_STD_VER > 17
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool starts_with(__self_view __sv) const noexcept
+    { return __self_view(data(), size()).starts_with(__sv); }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool starts_with(value_type __c) const noexcept
+    { return !empty() && _Traits::eq(front(), __c); }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool starts_with(const value_type* __s) const noexcept
+    { return starts_with(__self_view(__s)); }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool ends_with(__self_view __sv) const noexcept
+    { return __self_view(data(), size()).ends_with( __sv); }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool ends_with(value_type __c) const noexcept
+    { return !empty() && _Traits::eq(back(), __c); }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool ends_with(const value_type* __s) const noexcept
+    { return ends_with(__self_view(__s)); }
+//#endif
+
+#if _LIBCPP_STD_VER > 20
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool contains(__self_view __sv) const noexcept
+    { return __self_view(data(), size()).contains(__sv); }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool contains(value_type __c) const noexcept
+    { return __self_view(data(), size()).contains(__c); }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool contains(const value_type* __s) const
+    { return __self_view(data(), size()).contains(__s); }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY bool __invariants() const;
+
+    _LIBCPP_INLINE_VISIBILITY void __clear_and_shrink() _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY void __shrink_or_extend(size_type __target_capacity);
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool __is_long() const _NOEXCEPT
+        {return bool(__r_.first().__s.__size_ & __short_mask);}
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+    bool __dereferenceable(const const_iterator* __i) const;
+    bool __decrementable(const const_iterator* __i) const;
+    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
+    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type& __alloc() _NOEXCEPT
+        {return __r_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    const allocator_type& __alloc() const _NOEXCEPT
+        {return __r_.second();}
+
+#ifdef _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __set_short_size(size_type __s) _NOEXCEPT
+#   ifdef _LIBCPP_BIG_ENDIAN
+        {__r_.first().__s.__size_ = (unsigned char)(__s << 1);}
+#   else
+        {__r_.first().__s.__size_ = (unsigned char)(__s);}
+#   endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type __get_short_size() const _NOEXCEPT
+#   ifdef _LIBCPP_BIG_ENDIAN
+        {return __r_.first().__s.__size_ >> 1;}
+#   else
+        {return __r_.first().__s.__size_;}
+#   endif
+
+#else  // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __set_short_size(size_type __s) _NOEXCEPT
+#   ifdef _LIBCPP_BIG_ENDIAN
+        {__r_.first().__s.__size_ = (unsigned char)(__s);}
+#   else
+        {__r_.first().__s.__size_ = (unsigned char)(__s << 1);}
+#   endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type __get_short_size() const _NOEXCEPT
+#   ifdef _LIBCPP_BIG_ENDIAN
+        {return __r_.first().__s.__size_;}
+#   else
+        {return __r_.first().__s.__size_ >> 1;}
+#   endif
+
+#endif // _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __set_long_size(size_type __s) _NOEXCEPT
+        {__r_.first().__l.__size_ = __s;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type __get_long_size() const _NOEXCEPT
+        {return __r_.first().__l.__size_;}
+    _LIBCPP_INLINE_VISIBILITY
+    void __set_size(size_type __s) _NOEXCEPT
+        {if (__is_long()) __set_long_size(__s); else __set_short_size(__s);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __set_long_cap(size_type __s) _NOEXCEPT
+        {__r_.first().__l.__cap_  = __long_mask | __s;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type __get_long_cap() const _NOEXCEPT
+        {return __r_.first().__l.__cap_ & size_type(~__long_mask);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __set_long_pointer(pointer __p) _NOEXCEPT
+        {__r_.first().__l.__data_ = __p;}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer __get_long_pointer() _NOEXCEPT
+        {return __r_.first().__l.__data_;}
+    _LIBCPP_INLINE_VISIBILITY
+    const_pointer __get_long_pointer() const _NOEXCEPT
+        {return __r_.first().__l.__data_;}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer __get_short_pointer() _NOEXCEPT
+        {return pointer_traits<pointer>::pointer_to(__r_.first().__s.__data_[0]);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_pointer __get_short_pointer() const _NOEXCEPT
+        {return pointer_traits<const_pointer>::pointer_to(__r_.first().__s.__data_[0]);}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer __get_pointer() _NOEXCEPT
+        {return __is_long() ? __get_long_pointer() : __get_short_pointer();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_pointer __get_pointer() const _NOEXCEPT
+        {return __is_long() ? __get_long_pointer() : __get_short_pointer();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __zero() _NOEXCEPT
+        {
+            size_type (&__a)[__n_words] = __r_.first().__r.__words;
+            for (unsigned __i = 0; __i < __n_words; ++__i)
+                __a[__i] = 0;
+        }
+
+    template <size_type __a> static
+        _LIBCPP_INLINE_VISIBILITY
+        size_type __align_it(size_type __s) _NOEXCEPT
+            {return (__s + (__a-1)) & ~(__a-1);}
+    enum {__alignment = 16};
+    static _LIBCPP_INLINE_VISIBILITY
+    size_type __recommend(size_type __s) _NOEXCEPT
+        {
+        if (__s < __min_cap) return static_cast<size_type>(__min_cap) - 1;
+        size_type __guess = __align_it<sizeof(value_type) < __alignment ?
+                     __alignment/sizeof(value_type) : 1 > (__s+1) - 1;
+        if (__guess == __min_cap) ++__guess;
+        return __guess;
+        }
+
+    inline
+    void __init(const value_type* __s, size_type __sz, size_type __reserve);
+    inline
+    void __init(const value_type* __s, size_type __sz);
+    inline
+    void __init(size_type __n, value_type __c);
+
+    // Slow path for the (inlined) copy constructor for 'long' strings.
+    // Always externally instantiated and not inlined.
+    // Requires that __s is zero terminated.
+    // The main reason for this function to exist is because for unstable, we
+    // want to allow inlining of the copy constructor. However, we don't want
+    // to call the __init() functions as those are marked as inline which may
+    // result in over-aggressive inlining by the compiler, where our aim is
+    // to only inline the fast path code directly in the ctor.
+    void __init_copy_ctor_external(const value_type* __s, size_type __sz);
+
+    template <class _InputIterator>
+    inline
+    __enable_if_t
+    <
+        __is_exactly_cpp17_input_iterator<_InputIterator>::value
+    >
+    __init(_InputIterator __first, _InputIterator __last);
+
+    template <class _ForwardIterator>
+    inline
+    __enable_if_t
+    <
+        __is_cpp17_forward_iterator<_ForwardIterator>::value
+    >
+    __init(_ForwardIterator __first, _ForwardIterator __last);
+
+    void __grow_by(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
+                   size_type __n_copy,  size_type __n_del,     size_type __n_add = 0);
+    void __grow_by_and_replace(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
+                               size_type __n_copy,  size_type __n_del,
+                               size_type __n_add, const value_type* __p_new_stuff);
+
+    // __assign_no_alias is invoked for assignment operations where we
+    // have proof that the input does not alias the current instance.
+    // For example, operator=(basic_string) performs a 'self' check.
+    template <bool __is_short>
+    basic_string& __assign_no_alias(const value_type* __s, size_type __n);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __erase_to_end(size_type __pos);
+
+    // __erase_external_with_move is invoked for erase() invocations where
+    // `n ~= npos`, likely requiring memory moves on the string data.
+    void __erase_external_with_move(size_type __pos, size_type __n);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const basic_string& __str)
+        {__copy_assign_alloc(__str, integral_constant<bool,
+                      __alloc_traits::propagate_on_container_copy_assignment::value>());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const basic_string& __str, true_type)
+        {
+            if (__alloc() == __str.__alloc())
+                __alloc() = __str.__alloc();
+            else
+            {
+                if (!__str.__is_long())
+                {
+                    __clear_and_shrink();
+                    __alloc() = __str.__alloc();
+                }
+                else
+                {
+                    allocator_type __a = __str.__alloc();
+                    pointer __p = __alloc_traits::allocate(__a, __str.__get_long_cap());
+                    __clear_and_shrink();
+                    __alloc() = _VSTD::move(__a);
+                    __set_long_pointer(__p);
+                    __set_long_cap(__str.__get_long_cap());
+                    __set_long_size(__str.size());
+                }
+            }
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const basic_string&, false_type) _NOEXCEPT
+        {}
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign(basic_string& __str, false_type)
+        _NOEXCEPT_(__alloc_traits::is_always_equal::value);
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign(basic_string& __str, true_type)
+#if _LIBCPP_STD_VER > 14
+        _NOEXCEPT;
+#else
+        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value);
+#endif
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    void
+    __move_assign_alloc(basic_string& __str)
+        _NOEXCEPT_(
+            !__alloc_traits::propagate_on_container_move_assignment::value ||
+            is_nothrow_move_assignable<allocator_type>::value)
+    {__move_assign_alloc(__str, integral_constant<bool,
+                      __alloc_traits::propagate_on_container_move_assignment::value>());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(basic_string& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
+        {
+            __alloc() = _VSTD::move(__c.__alloc());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(basic_string&, false_type)
+        _NOEXCEPT
+        {}
+
+    basic_string& __assign_external(const value_type* __s);
+    basic_string& __assign_external(const value_type* __s, size_type __n);
+
+    // Assigns the value in __s, guaranteed to be __n < __min_cap in length.
+    inline basic_string& __assign_short(const value_type* __s, size_type __n) {
+      pointer __p = __is_long()
+                        ? (__set_long_size(__n), __get_long_pointer())
+                        : (__set_short_size(__n), __get_short_pointer());
+      traits_type::move(_VSTD::__to_address(__p), __s, __n);
+      traits_type::assign(__p[__n], value_type());
+      return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY void __invalidate_all_iterators();
+    _LIBCPP_INLINE_VISIBILITY void __invalidate_iterators_past(size_type);
+
+    template<class _Tp>
+    _LIBCPP_INLINE_VISIBILITY
+    bool __addr_in_range(_Tp&& __t) const {
+        const volatile void *__p = _VSTD::addressof(__t);
+        return data() <= __p && __p <= data() + size();
+    }
+
+    _LIBCPP_NORETURN _LIBCPP_HIDE_FROM_ABI
+    void __throw_length_error() const {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        __basic_string_common<true>::__throw_length_error();
+#else
+        _VSTD::abort();
+#endif
+    }
+
+    _LIBCPP_NORETURN _LIBCPP_HIDE_FROM_ABI
+    void __throw_out_of_range() const {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        __basic_string_common<true>::__throw_out_of_range();
+#else
+        _VSTD::abort();
+#endif
+    }
+
+    friend basic_string operator+<>(const basic_string&, const basic_string&);
+    friend basic_string operator+<>(const value_type*, const basic_string&);
+    friend basic_string operator+<>(value_type, const basic_string&);
+    friend basic_string operator+<>(const basic_string&, const value_type*);
+    friend basic_string operator+<>(const basic_string&, value_type);
+};
+
+// These declarations must appear before any functions are implicitly used
+// so that they have the correct visibility specifier.
+#ifdef _LIBCPP_ABI_STRING_OPTIMIZED_EXTERNAL_INSTANTIATION
+    _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE, char)
+#   ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE, wchar_t)
+#   endif
+#else
+    _LIBCPP_STRING_V1_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE, char)
+#   ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        _LIBCPP_STRING_V1_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE, wchar_t)
+#   endif
+#endif
+
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator,
+         class _CharT = __iter_value_type<_InputIterator>,
+         class _Allocator = allocator<_CharT>,
+         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>
+         >
+basic_string(_InputIterator, _InputIterator, _Allocator = _Allocator())
+  -> basic_string<_CharT, char_traits<_CharT>, _Allocator>;
+
+template<class _CharT,
+         class _Traits,
+         class _Allocator = allocator<_CharT>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>
+         >
+explicit basic_string(basic_string_view<_CharT, _Traits>, const _Allocator& = _Allocator())
+  -> basic_string<_CharT, _Traits, _Allocator>;
+
+template<class _CharT,
+         class _Traits,
+         class _Allocator = allocator<_CharT>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>,
+         class _Sz = typename allocator_traits<_Allocator>::size_type
+         >
+basic_string(basic_string_view<_CharT, _Traits>, _Sz, _Sz, const _Allocator& = _Allocator())
+  -> basic_string<_CharT, _Traits, _Allocator>;
+#endif
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+void
+basic_string<_CharT, _Traits, _Allocator>::__invalidate_all_iterators()
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__invalidate_all(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+void
+basic_string<_CharT, _Traits, _Allocator>::__invalidate_iterators_past(size_type __pos)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __c_node* __c = __get_db()->__find_c_and_lock(this);
+    if (__c)
+    {
+        const_pointer __new_last = __get_pointer() + __pos;
+        for (__i_node** __p = __c->end_; __p != __c->beg_; )
+        {
+            --__p;
+            const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);
+            if (__i->base() > __new_last)
+            {
+                (*__p)->__c_ = nullptr;
+                if (--__c->end_ != __p)
+                    _VSTD::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
+            }
+        }
+        __get_db()->unlock();
+    }
+#else
+    (void)__pos;
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>::basic_string()
+    _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
+     : __r_(__default_init_tag(), __default_init_tag())
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __zero();
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>::basic_string(const allocator_type& __a)
+#if _LIBCPP_STD_VER <= 14
+        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
+#else
+        _NOEXCEPT
+#endif
+: __r_(__default_init_tag(), __a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __zero();
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+void basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s,
+                                                       size_type __sz,
+                                                       size_type __reserve)
+{
+    if (__reserve > max_size())
+        this->__throw_length_error();
+    pointer __p;
+    if (__reserve < __min_cap)
+    {
+        __set_short_size(__sz);
+        __p = __get_short_pointer();
+    }
+    else
+    {
+        size_type __cap = __recommend(__reserve);
+        __p = __alloc_traits::allocate(__alloc(), __cap+1);
+        __set_long_pointer(__p);
+        __set_long_cap(__cap+1);
+        __set_long_size(__sz);
+    }
+    traits_type::copy(_VSTD::__to_address(__p), __s, __sz);
+    traits_type::assign(__p[__sz], value_type());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+void
+basic_string<_CharT, _Traits, _Allocator>::__init(const value_type* __s, size_type __sz)
+{
+    if (__sz > max_size())
+        this->__throw_length_error();
+    pointer __p;
+    if (__sz < __min_cap)
+    {
+        __set_short_size(__sz);
+        __p = __get_short_pointer();
+    }
+    else
+    {
+        size_type __cap = __recommend(__sz);
+        __p = __alloc_traits::allocate(__alloc(), __cap+1);
+        __set_long_pointer(__p);
+        __set_long_cap(__cap+1);
+        __set_long_size(__sz);
+    }
+    traits_type::copy(_VSTD::__to_address(__p), __s, __sz);
+    traits_type::assign(__p[__sz], value_type());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class>
+basic_string<_CharT, _Traits, _Allocator>::basic_string(const _CharT* __s, const _Allocator& __a)
+    : __r_(__default_init_tag(), __a)
+{
+    _LIBCPP_ASSERT(__s != nullptr, "basic_string(const char*, allocator) detected nullptr");
+    __init(__s, traits_type::length(__s));
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>::basic_string(const _CharT* __s, size_type __n)
+     : __r_(__default_init_tag(), __default_init_tag())
+{
+    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n) detected nullptr");
+    __init(__s, __n);
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>::basic_string(const _CharT* __s, size_type __n, const _Allocator& __a)
+    : __r_(__default_init_tag(), __a)
+{
+    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "basic_string(const char*, n, allocator) detected nullptr");
+    __init(__s, __n);
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str)
+    : __r_(__default_init_tag(), __alloc_traits::select_on_container_copy_construction(__str.__alloc()))
+{
+    if (!__str.__is_long())
+        __r_.first().__r = __str.__r_.first().__r;
+    else
+        __init_copy_ctor_external(_VSTD::__to_address(__str.__get_long_pointer()),
+                                  __str.__get_long_size());
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>::basic_string(
+    const basic_string& __str, const allocator_type& __a)
+    : __r_(__default_init_tag(), __a)
+{
+    if (!__str.__is_long())
+        __r_.first().__r = __str.__r_.first().__r;
+    else
+        __init_copy_ctor_external(_VSTD::__to_address(__str.__get_long_pointer()),
+                                  __str.__get_long_size());
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+void basic_string<_CharT, _Traits, _Allocator>::__init_copy_ctor_external(
+    const value_type* __s, size_type __sz) {
+  pointer __p;
+  if (__sz < __min_cap) {
+    __p = __get_short_pointer();
+    __set_short_size(__sz);
+  } else {
+    if (__sz > max_size())
+      this->__throw_length_error();
+    size_t __cap = __recommend(__sz);
+    __p = __alloc_traits::allocate(__alloc(), __cap + 1);
+    __set_long_pointer(__p);
+    __set_long_cap(__cap + 1);
+    __set_long_size(__sz);
+  }
+  traits_type::copy(_VSTD::__to_address(__p), __s, __sz + 1);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>::basic_string(basic_string&& __str)
+#if _LIBCPP_STD_VER <= 14
+        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
+#else
+        _NOEXCEPT
+#endif
+    : __r_(_VSTD::move(__str.__r_))
+{
+    __str.__zero();
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+    if (__is_long())
+        __get_db()->swap(this, &__str);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>::basic_string(basic_string&& __str, const allocator_type& __a)
+    : __r_(__default_init_tag(), __a)
+{
+    if (__str.__is_long() && __a != __str.__alloc()) // copy, not move
+        __init(_VSTD::__to_address(__str.__get_long_pointer()), __str.__get_long_size());
+    else
+    {
+        __r_.first().__r = __str.__r_.first().__r;
+        __str.__zero();
+    }
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+    if (__is_long())
+        __get_db()->swap(this, &__str);
+#endif
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _CharT, class _Traits, class _Allocator>
+void
+basic_string<_CharT, _Traits, _Allocator>::__init(size_type __n, value_type __c)
+{
+    if (__n > max_size())
+        this->__throw_length_error();
+    pointer __p;
+    if (__n < __min_cap)
+    {
+        __set_short_size(__n);
+        __p = __get_short_pointer();
+    }
+    else
+    {
+        size_type __cap = __recommend(__n);
+        __p = __alloc_traits::allocate(__alloc(), __cap+1);
+        __set_long_pointer(__p);
+        __set_long_cap(__cap+1);
+        __set_long_size(__n);
+    }
+    traits_type::assign(_VSTD::__to_address(__p), __n, __c);
+    traits_type::assign(__p[__n], value_type());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>::basic_string(size_type __n, _CharT __c)
+     : __r_(__default_init_tag(), __default_init_tag())
+{
+    __init(__n, __c);
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class>
+basic_string<_CharT, _Traits, _Allocator>::basic_string(size_type __n, _CharT __c, const _Allocator& __a)
+    : __r_(__default_init_tag(), __a)
+{
+    __init(__n, __c);
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str,
+                                                        size_type __pos, size_type __n,
+                                                        const _Allocator& __a)
+    : __r_(__default_init_tag(), __a)
+{
+    size_type __str_sz = __str.size();
+    if (__pos > __str_sz)
+        this->__throw_out_of_range();
+    __init(__str.data() + __pos, _VSTD::min(__n, __str_sz - __pos));
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>::basic_string(const basic_string& __str, size_type __pos,
+                                                        const _Allocator& __a)
+    : __r_(__default_init_tag(), __a)
+{
+    size_type __str_sz = __str.size();
+    if (__pos > __str_sz)
+        this->__throw_out_of_range();
+    __init(__str.data() + __pos, __str_sz - __pos);
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp, class>
+basic_string<_CharT, _Traits, _Allocator>::basic_string(
+             const _Tp& __t, size_type __pos, size_type __n, const allocator_type& __a)
+    : __r_(__default_init_tag(), __a)
+{
+    __self_view __sv0 = __t;
+    __self_view __sv = __sv0.substr(__pos, __n);
+    __init(__sv.data(), __sv.size());
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp, class>
+basic_string<_CharT, _Traits, _Allocator>::basic_string(const _Tp & __t)
+     : __r_(__default_init_tag(), __default_init_tag())
+{
+    __self_view __sv = __t;
+    __init(__sv.data(), __sv.size());
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp, class>
+basic_string<_CharT, _Traits, _Allocator>::basic_string(const _Tp & __t, const _Allocator& __a)
+    : __r_(__default_init_tag(), __a)
+{
+    __self_view __sv = __t;
+    __init(__sv.data(), __sv.size());
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _InputIterator>
+__enable_if_t
+<
+    __is_exactly_cpp17_input_iterator<_InputIterator>::value
+>
+basic_string<_CharT, _Traits, _Allocator>::__init(_InputIterator __first, _InputIterator __last)
+{
+    __zero();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+    for (; __first != __last; ++__first)
+        push_back(*__first);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        if (__is_long())
+            __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
+        throw;
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _ForwardIterator>
+__enable_if_t
+<
+    __is_cpp17_forward_iterator<_ForwardIterator>::value
+>
+basic_string<_CharT, _Traits, _Allocator>::__init(_ForwardIterator __first, _ForwardIterator __last)
+{
+    size_type __sz = static_cast<size_type>(_VSTD::distance(__first, __last));
+    if (__sz > max_size())
+        this->__throw_length_error();
+    pointer __p;
+    if (__sz < __min_cap)
+    {
+        __set_short_size(__sz);
+        __p = __get_short_pointer();
+    }
+    else
+    {
+        size_type __cap = __recommend(__sz);
+        __p = __alloc_traits::allocate(__alloc(), __cap+1);
+        __set_long_pointer(__p);
+        __set_long_cap(__cap+1);
+        __set_long_size(__sz);
+    }
+
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif  // _LIBCPP_NO_EXCEPTIONS
+    for (; __first != __last; ++__first, (void) ++__p)
+        traits_type::assign(*__p, *__first);
+    traits_type::assign(*__p, value_type());
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        if (__is_long())
+            __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
+        throw;
+    }
+#endif  // _LIBCPP_NO_EXCEPTIONS
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _InputIterator, class>
+inline
+basic_string<_CharT, _Traits, _Allocator>::basic_string(_InputIterator __first, _InputIterator __last)
+     : __r_(__default_init_tag(), __default_init_tag())
+{
+    __init(__first, __last);
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _InputIterator, class>
+inline
+basic_string<_CharT, _Traits, _Allocator>::basic_string(_InputIterator __first, _InputIterator __last,
+                                                        const allocator_type& __a)
+    : __r_(__default_init_tag(), __a)
+{
+    __init(__first, __last);
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>::basic_string(
+    initializer_list<_CharT> __il)
+     : __r_(__default_init_tag(), __default_init_tag())
+{
+    __init(__il.begin(), __il.end());
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+
+basic_string<_CharT, _Traits, _Allocator>::basic_string(
+    initializer_list<_CharT> __il, const _Allocator& __a)
+    : __r_(__default_init_tag(), __a)
+{
+    __init(__il.begin(), __il.end());
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>::~basic_string()
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__erase_c(this);
+#endif
+    if (__is_long())
+        __alloc_traits::deallocate(__alloc(), __get_long_pointer(), __get_long_cap());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+void
+basic_string<_CharT, _Traits, _Allocator>::__grow_by_and_replace
+    (size_type __old_cap, size_type __delta_cap, size_type __old_sz,
+     size_type __n_copy,  size_type __n_del,     size_type __n_add, const value_type* __p_new_stuff)
+{
+    size_type __ms = max_size();
+    if (__delta_cap > __ms - __old_cap - 1)
+        this->__throw_length_error();
+    pointer __old_p = __get_pointer();
+    size_type __cap = __old_cap < __ms / 2 - __alignment ?
+                          __recommend(_VSTD::max(__old_cap + __delta_cap, 2 * __old_cap)) :
+                          __ms - 1;
+    pointer __p = __alloc_traits::allocate(__alloc(), __cap+1);
+    __invalidate_all_iterators();
+    if (__n_copy != 0)
+        traits_type::copy(_VSTD::__to_address(__p),
+                          _VSTD::__to_address(__old_p), __n_copy);
+    if (__n_add != 0)
+        traits_type::copy(_VSTD::__to_address(__p) + __n_copy, __p_new_stuff, __n_add);
+    size_type __sec_cp_sz = __old_sz - __n_del - __n_copy;
+    if (__sec_cp_sz != 0)
+        traits_type::copy(_VSTD::__to_address(__p) + __n_copy + __n_add,
+                          _VSTD::__to_address(__old_p) + __n_copy + __n_del, __sec_cp_sz);
+    if (__old_cap+1 != __min_cap)
+        __alloc_traits::deallocate(__alloc(), __old_p, __old_cap+1);
+    __set_long_pointer(__p);
+    __set_long_cap(__cap+1);
+    __old_sz = __n_copy + __n_add + __sec_cp_sz;
+    __set_long_size(__old_sz);
+    traits_type::assign(__p[__old_sz], value_type());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+void
+basic_string<_CharT, _Traits, _Allocator>::__grow_by(size_type __old_cap, size_type __delta_cap, size_type __old_sz,
+                                                     size_type __n_copy,  size_type __n_del,     size_type __n_add)
+{
+    size_type __ms = max_size();
+    if (__delta_cap > __ms - __old_cap)
+        this->__throw_length_error();
+    pointer __old_p = __get_pointer();
+    size_type __cap = __old_cap < __ms / 2 - __alignment ?
+                          __recommend(_VSTD::max(__old_cap + __delta_cap, 2 * __old_cap)) :
+                          __ms - 1;
+    pointer __p = __alloc_traits::allocate(__alloc(), __cap+1);
+    __invalidate_all_iterators();
+    if (__n_copy != 0)
+        traits_type::copy(_VSTD::__to_address(__p),
+                          _VSTD::__to_address(__old_p), __n_copy);
+    size_type __sec_cp_sz = __old_sz - __n_del - __n_copy;
+    if (__sec_cp_sz != 0)
+        traits_type::copy(_VSTD::__to_address(__p) + __n_copy + __n_add,
+                          _VSTD::__to_address(__old_p) + __n_copy + __n_del,
+                          __sec_cp_sz);
+    if (__old_cap+1 != __min_cap)
+        __alloc_traits::deallocate(__alloc(), __old_p, __old_cap+1);
+    __set_long_pointer(__p);
+    __set_long_cap(__cap+1);
+}
+
+// assign
+
+template <class _CharT, class _Traits, class _Allocator>
+template <bool __is_short>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::__assign_no_alias(
+    const value_type* __s, size_type __n) {
+  size_type __cap = __is_short ? __min_cap : __get_long_cap();
+  if (__n < __cap) {
+    pointer __p = __is_short ? __get_short_pointer() : __get_long_pointer();
+    __is_short ? __set_short_size(__n) : __set_long_size(__n);
+    traits_type::copy(_VSTD::__to_address(__p), __s, __n);
+    traits_type::assign(__p[__n], value_type());
+    __invalidate_iterators_past(__n);
+  } else {
+    size_type __sz = __is_short ? __get_short_size() : __get_long_size();
+    __grow_by_and_replace(__cap - 1, __n - __cap + 1, __sz, 0, __sz, __n, __s);
+  }
+  return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::__assign_external(
+    const value_type* __s, size_type __n) {
+  size_type __cap = capacity();
+  if (__cap >= __n) {
+    value_type* __p = _VSTD::__to_address(__get_pointer());
+    traits_type::move(__p, __s, __n);
+    traits_type::assign(__p[__n], value_type());
+    __set_size(__n);
+    __invalidate_iterators_past(__n);
+  } else {
+    size_type __sz = size();
+    __grow_by_and_replace(__cap, __n - __cap, __sz, 0, __sz, __n, __s);
+  }
+  return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s, size_type __n)
+{
+    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::assign received nullptr");
+    return (_LIBCPP_BUILTIN_CONSTANT_P(__n) && __n < __min_cap)
+               ? __assign_short(__s, __n)
+               : __assign_external(__s, __n);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::assign(size_type __n, value_type __c)
+{
+    size_type __cap = capacity();
+    if (__cap < __n)
+    {
+        size_type __sz = size();
+        __grow_by(__cap, __n - __cap, __sz, 0, __sz);
+    }
+    value_type* __p = _VSTD::__to_address(__get_pointer());
+    traits_type::assign(__p, __n, __c);
+    traits_type::assign(__p[__n], value_type());
+    __set_size(__n);
+    __invalidate_iterators_past(__n);
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::operator=(value_type __c)
+{
+    pointer __p;
+    if (__is_long())
+    {
+        __p = __get_long_pointer();
+        __set_long_size(1);
+    }
+    else
+    {
+        __p = __get_short_pointer();
+        __set_short_size(1);
+    }
+    traits_type::assign(*__p, __c);
+    traits_type::assign(*++__p, value_type());
+    __invalidate_iterators_past(1);
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::operator=(const basic_string& __str)
+{
+  if (this != &__str) {
+    __copy_assign_alloc(__str);
+    if (!__is_long()) {
+      if (!__str.__is_long()) {
+        __r_.first().__r = __str.__r_.first().__r;
+      } else {
+        return __assign_no_alias<true>(__str.data(), __str.size());
+      }
+    } else {
+      return __assign_no_alias<false>(__str.data(), __str.size());
+    }
+  }
+  return *this;
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+void
+basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, false_type)
+    _NOEXCEPT_(__alloc_traits::is_always_equal::value)
+{
+    if (__alloc() != __str.__alloc())
+        assign(__str);
+    else
+        __move_assign(__str, true_type());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+void
+basic_string<_CharT, _Traits, _Allocator>::__move_assign(basic_string& __str, true_type)
+#if _LIBCPP_STD_VER > 14
+    _NOEXCEPT
+#else
+    _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
+#endif
+{
+  if (__is_long()) {
+    __alloc_traits::deallocate(__alloc(), __get_long_pointer(),
+                               __get_long_cap());
+#if _LIBCPP_STD_VER <= 14
+    if (!is_nothrow_move_assignable<allocator_type>::value) {
+      __set_short_size(0);
+      traits_type::assign(__get_short_pointer()[0], value_type());
+    }
+#endif
+  }
+  __move_assign_alloc(__str);
+  __r_.first() = __str.__r_.first();
+  __str.__set_short_size(0);
+  traits_type::assign(__str.__get_short_pointer()[0], value_type());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::operator=(basic_string&& __str)
+    _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
+{
+    __move_assign(__str, integral_constant<bool,
+          __alloc_traits::propagate_on_container_move_assignment::value>());
+    return *this;
+}
+
+#endif
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _InputIterator>
+__enable_if_t
+<
+     __is_exactly_cpp17_input_iterator<_InputIterator>::value,
+    basic_string<_CharT, _Traits, _Allocator>&
+>
+basic_string<_CharT, _Traits, _Allocator>::assign(_InputIterator __first, _InputIterator __last)
+{
+    const basic_string __temp(__first, __last, __alloc());
+    assign(__temp.data(), __temp.size());
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _ForwardIterator>
+__enable_if_t
+<
+    __is_cpp17_forward_iterator<_ForwardIterator>::value,
+    basic_string<_CharT, _Traits, _Allocator>&
+>
+basic_string<_CharT, _Traits, _Allocator>::assign(_ForwardIterator __first, _ForwardIterator __last)
+{
+    size_type __cap = capacity();
+    size_type __n = __string_is_trivial_iterator<_ForwardIterator>::value ?
+        static_cast<size_type>(_VSTD::distance(__first, __last)) : 0;
+
+    if (__string_is_trivial_iterator<_ForwardIterator>::value &&
+        (__cap >= __n || !__addr_in_range(*__first)))
+    {
+        if (__cap < __n)
+        {
+            size_type __sz = size();
+            __grow_by(__cap, __n - __cap, __sz, 0, __sz);
+        }
+        pointer __p = __get_pointer();
+        for (; __first != __last; ++__p, (void) ++__first)
+            traits_type::assign(*__p, *__first);
+        traits_type::assign(*__p, value_type());
+        __set_size(__n);
+        __invalidate_iterators_past(__n);
+    }
+    else
+    {
+        const basic_string __temp(__first, __last, __alloc());
+        assign(__temp.data(), __temp.size());
+    }
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::assign(const basic_string& __str, size_type __pos, size_type __n)
+{
+    size_type __sz = __str.size();
+    if (__pos > __sz)
+        this->__throw_out_of_range();
+    return assign(__str.data() + __pos, _VSTD::min(__n, __sz - __pos));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp>
+__enable_if_t
+<
+    __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
+    && !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
+    basic_string<_CharT, _Traits, _Allocator>&
+>
+basic_string<_CharT, _Traits, _Allocator>::assign(const _Tp & __t, size_type __pos, size_type __n)
+{
+    __self_view __sv = __t;
+    size_type __sz = __sv.size();
+    if (__pos > __sz)
+        this->__throw_out_of_range();
+    return assign(__sv.data() + __pos, _VSTD::min(__n, __sz - __pos));
+}
+
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::__assign_external(const value_type* __s) {
+  return __assign_external(__s, traits_type::length(__s));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::assign(const value_type* __s)
+{
+    _LIBCPP_ASSERT(__s != nullptr, "string::assign received nullptr");
+    return _LIBCPP_BUILTIN_CONSTANT_P(*__s)
+               ? (traits_type::length(__s) < __min_cap
+                      ? __assign_short(__s, traits_type::length(__s))
+                      : __assign_external(__s, traits_type::length(__s)))
+               : __assign_external(__s);
+}
+// append
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::append(const value_type* __s, size_type __n)
+{
+    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::append received nullptr");
+    size_type __cap = capacity();
+    size_type __sz = size();
+    if (__cap - __sz >= __n)
+    {
+        if (__n)
+        {
+            value_type* __p = _VSTD::__to_address(__get_pointer());
+            traits_type::copy(__p + __sz, __s, __n);
+            __sz += __n;
+            __set_size(__sz);
+            traits_type::assign(__p[__sz], value_type());
+        }
+    }
+    else
+        __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __sz, 0, __n, __s);
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::append(size_type __n, value_type __c)
+{
+    if (__n)
+    {
+        size_type __cap = capacity();
+        size_type __sz = size();
+        if (__cap - __sz < __n)
+            __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
+        pointer __p = __get_pointer();
+        traits_type::assign(_VSTD::__to_address(__p) + __sz, __n, __c);
+        __sz += __n;
+        __set_size(__sz);
+        traits_type::assign(__p[__sz], value_type());
+    }
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline void
+basic_string<_CharT, _Traits, _Allocator>::__append_default_init(size_type __n)
+{
+    if (__n)
+    {
+        size_type __cap = capacity();
+        size_type __sz = size();
+        if (__cap - __sz < __n)
+            __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
+        pointer __p = __get_pointer();
+        __sz += __n;
+        __set_size(__sz);
+        traits_type::assign(__p[__sz], value_type());
+    }
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+void
+basic_string<_CharT, _Traits, _Allocator>::push_back(value_type __c)
+{
+    bool __is_short = !__is_long();
+    size_type __cap;
+    size_type __sz;
+    if (__is_short)
+    {
+        __cap = __min_cap - 1;
+        __sz = __get_short_size();
+    }
+    else
+    {
+        __cap = __get_long_cap() - 1;
+        __sz = __get_long_size();
+    }
+    if (__sz == __cap)
+    {
+        __grow_by(__cap, 1, __sz, __sz, 0);
+        __is_short = !__is_long();
+    }
+    pointer __p;
+    if (__is_short)
+    {
+        __p = __get_short_pointer() + __sz;
+        __set_short_size(__sz+1);
+    }
+    else
+    {
+        __p = __get_long_pointer() + __sz;
+        __set_long_size(__sz+1);
+    }
+    traits_type::assign(*__p, __c);
+    traits_type::assign(*++__p, value_type());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _ForwardIterator>
+__enable_if_t
+<
+    __is_cpp17_forward_iterator<_ForwardIterator>::value,
+    basic_string<_CharT, _Traits, _Allocator>&
+>
+basic_string<_CharT, _Traits, _Allocator>::append(
+    _ForwardIterator __first, _ForwardIterator __last)
+{
+    size_type __sz = size();
+    size_type __cap = capacity();
+    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
+    if (__n)
+    {
+        if (__string_is_trivial_iterator<_ForwardIterator>::value &&
+            !__addr_in_range(*__first))
+        {
+            if (__cap - __sz < __n)
+                __grow_by(__cap, __sz + __n - __cap, __sz, __sz, 0);
+            pointer __p = __get_pointer() + __sz;
+            for (; __first != __last; ++__p, (void) ++__first)
+                traits_type::assign(*__p, *__first);
+            traits_type::assign(*__p, value_type());
+            __set_size(__sz + __n);
+        }
+        else
+        {
+            const basic_string __temp(__first, __last, __alloc());
+            append(__temp.data(), __temp.size());
+        }
+    }
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::append(const basic_string& __str)
+{
+    return append(__str.data(), __str.size());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::append(const basic_string& __str, size_type __pos, size_type __n)
+{
+    size_type __sz = __str.size();
+    if (__pos > __sz)
+        this->__throw_out_of_range();
+    return append(__str.data() + __pos, _VSTD::min(__n, __sz - __pos));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp>
+    __enable_if_t
+    <
+        __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value  && !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
+        basic_string<_CharT, _Traits, _Allocator>&
+    >
+basic_string<_CharT, _Traits, _Allocator>::append(const _Tp & __t, size_type __pos, size_type __n)
+{
+    __self_view __sv = __t;
+    size_type __sz = __sv.size();
+    if (__pos > __sz)
+        this->__throw_out_of_range();
+    return append(__sv.data() + __pos, _VSTD::min(__n, __sz - __pos));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::append(const value_type* __s)
+{
+    _LIBCPP_ASSERT(__s != nullptr, "string::append received nullptr");
+    return append(__s, traits_type::length(__s));
+}
+
+// insert
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, const value_type* __s, size_type __n)
+{
+    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::insert received nullptr");
+    size_type __sz = size();
+    if (__pos > __sz)
+        this->__throw_out_of_range();
+    size_type __cap = capacity();
+    if (__cap - __sz >= __n)
+    {
+        if (__n)
+        {
+            value_type* __p = _VSTD::__to_address(__get_pointer());
+            size_type __n_move = __sz - __pos;
+            if (__n_move != 0)
+            {
+                if (__p + __pos <= __s && __s < __p + __sz)
+                    __s += __n;
+                traits_type::move(__p + __pos + __n, __p + __pos, __n_move);
+            }
+            traits_type::move(__p + __pos, __s, __n);
+            __sz += __n;
+            __set_size(__sz);
+            traits_type::assign(__p[__sz], value_type());
+        }
+    }
+    else
+        __grow_by_and_replace(__cap, __sz + __n - __cap, __sz, __pos, 0, __n, __s);
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, size_type __n, value_type __c)
+{
+    size_type __sz = size();
+    if (__pos > __sz)
+        this->__throw_out_of_range();
+    if (__n)
+    {
+        size_type __cap = capacity();
+        value_type* __p;
+        if (__cap - __sz >= __n)
+        {
+            __p = _VSTD::__to_address(__get_pointer());
+            size_type __n_move = __sz - __pos;
+            if (__n_move != 0)
+                traits_type::move(__p + __pos + __n, __p + __pos, __n_move);
+        }
+        else
+        {
+            __grow_by(__cap, __sz + __n - __cap, __sz, __pos, 0, __n);
+            __p = _VSTD::__to_address(__get_long_pointer());
+        }
+        traits_type::assign(__p + __pos, __n, __c);
+        __sz += __n;
+        __set_size(__sz);
+        traits_type::assign(__p[__sz], value_type());
+    }
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _InputIterator>
+__enable_if_t
+<
+   __is_exactly_cpp17_input_iterator<_InputIterator>::value,
+   typename basic_string<_CharT, _Traits, _Allocator>::iterator
+>
+basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _InputIterator __first, _InputIterator __last)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
+        "string::insert(iterator, range) called with an iterator not"
+        " referring to this string");
+#endif
+    const basic_string __temp(__first, __last, __alloc());
+    return insert(__pos, __temp.data(), __temp.data() + __temp.size());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _ForwardIterator>
+__enable_if_t
+<
+    __is_cpp17_forward_iterator<_ForwardIterator>::value,
+    typename basic_string<_CharT, _Traits, _Allocator>::iterator
+>
+basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, _ForwardIterator __first, _ForwardIterator __last)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
+        "string::insert(iterator, range) called with an iterator not"
+        " referring to this string");
+#endif
+    size_type __ip = static_cast<size_type>(__pos - begin());
+    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
+    if (__n)
+    {
+        if (__string_is_trivial_iterator<_ForwardIterator>::value &&
+            !__addr_in_range(*__first))
+        {
+            size_type __sz = size();
+            size_type __cap = capacity();
+            value_type* __p;
+            if (__cap - __sz >= __n)
+            {
+                __p = _VSTD::__to_address(__get_pointer());
+                size_type __n_move = __sz - __ip;
+                if (__n_move != 0)
+                    traits_type::move(__p + __ip + __n, __p + __ip, __n_move);
+            }
+            else
+            {
+                __grow_by(__cap, __sz + __n - __cap, __sz, __ip, 0, __n);
+                __p = _VSTD::__to_address(__get_long_pointer());
+            }
+            __sz += __n;
+            __set_size(__sz);
+            traits_type::assign(__p[__sz], value_type());
+            for (__p += __ip; __first != __last; ++__p, (void) ++__first)
+                traits_type::assign(*__p, *__first);
+        }
+        else
+        {
+            const basic_string __temp(__first, __last, __alloc());
+            return insert(__pos, __temp.data(), __temp.data() + __temp.size());
+        }
+    }
+    return begin() + __ip;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const basic_string& __str)
+{
+    return insert(__pos1, __str.data(), __str.size());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const basic_string& __str,
+                                                  size_type __pos2, size_type __n)
+{
+    size_type __str_sz = __str.size();
+    if (__pos2 > __str_sz)
+        this->__throw_out_of_range();
+    return insert(__pos1, __str.data() + __pos2, _VSTD::min(__n, __str_sz - __pos2));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp>
+__enable_if_t
+<
+    __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value  && !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
+    basic_string<_CharT, _Traits, _Allocator>&
+>
+basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos1, const _Tp& __t,
+                                                  size_type __pos2, size_type __n)
+{
+    __self_view __sv = __t;
+    size_type __str_sz = __sv.size();
+    if (__pos2 > __str_sz)
+        this->__throw_out_of_range();
+    return insert(__pos1, __sv.data() + __pos2, _VSTD::min(__n, __str_sz - __pos2));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::insert(size_type __pos, const value_type* __s)
+{
+    _LIBCPP_ASSERT(__s != nullptr, "string::insert received nullptr");
+    return insert(__pos, __s, traits_type::length(__s));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+typename basic_string<_CharT, _Traits, _Allocator>::iterator
+basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, value_type __c)
+{
+    size_type __ip = static_cast<size_type>(__pos - begin());
+    size_type __sz = size();
+    size_type __cap = capacity();
+    value_type* __p;
+    if (__cap == __sz)
+    {
+        __grow_by(__cap, 1, __sz, __ip, 0, 1);
+        __p = _VSTD::__to_address(__get_long_pointer());
+    }
+    else
+    {
+        __p = _VSTD::__to_address(__get_pointer());
+        size_type __n_move = __sz - __ip;
+        if (__n_move != 0)
+            traits_type::move(__p + __ip + 1, __p + __ip, __n_move);
+    }
+    traits_type::assign(__p[__ip], __c);
+    traits_type::assign(__p[++__sz], value_type());
+    __set_size(__sz);
+    return begin() + static_cast<difference_type>(__ip);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::iterator
+basic_string<_CharT, _Traits, _Allocator>::insert(const_iterator __pos, size_type __n, value_type __c)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
+        "string::insert(iterator, n, value) called with an iterator not"
+        " referring to this string");
+#endif
+    difference_type __p = __pos - begin();
+    insert(static_cast<size_type>(__p), __n, __c);
+    return begin() + __p;
+}
+
+// replace
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, const value_type* __s, size_type __n2)
+    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+{
+    _LIBCPP_ASSERT(__n2 == 0 || __s != nullptr, "string::replace received nullptr");
+    size_type __sz = size();
+    if (__pos > __sz)
+        this->__throw_out_of_range();
+    __n1 = _VSTD::min(__n1, __sz - __pos);
+    size_type __cap = capacity();
+    if (__cap - __sz + __n1 >= __n2)
+    {
+        value_type* __p = _VSTD::__to_address(__get_pointer());
+        if (__n1 != __n2)
+        {
+            size_type __n_move = __sz - __pos - __n1;
+            if (__n_move != 0)
+            {
+                if (__n1 > __n2)
+                {
+                    traits_type::move(__p + __pos, __s, __n2);
+                    traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
+                    goto __finish;
+                }
+                if (__p + __pos < __s && __s < __p + __sz)
+                {
+                    if (__p + __pos + __n1 <= __s)
+                        __s += __n2 - __n1;
+                    else // __p + __pos < __s < __p + __pos + __n1
+                    {
+                        traits_type::move(__p + __pos, __s, __n1);
+                        __pos += __n1;
+                        __s += __n2;
+                        __n2 -= __n1;
+                        __n1 = 0;
+                    }
+                }
+                traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
+            }
+        }
+        traits_type::move(__p + __pos, __s, __n2);
+__finish:
+// __sz += __n2 - __n1; in this and the below function below can cause unsigned
+// integer overflow, but this is a safe operation, so we disable the check.
+        __sz += __n2 - __n1;
+        __set_size(__sz);
+        __invalidate_iterators_past(__sz);
+        traits_type::assign(__p[__sz], value_type());
+    }
+    else
+        __grow_by_and_replace(__cap, __sz - __n1 + __n2 - __cap, __sz, __pos, __n1, __n2, __s);
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, size_type __n2, value_type __c)
+    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
+{
+    size_type __sz = size();
+    if (__pos > __sz)
+        this->__throw_out_of_range();
+    __n1 = _VSTD::min(__n1, __sz - __pos);
+    size_type __cap = capacity();
+    value_type* __p;
+    if (__cap - __sz + __n1 >= __n2)
+    {
+        __p = _VSTD::__to_address(__get_pointer());
+        if (__n1 != __n2)
+        {
+            size_type __n_move = __sz - __pos - __n1;
+            if (__n_move != 0)
+                traits_type::move(__p + __pos + __n2, __p + __pos + __n1, __n_move);
+        }
+    }
+    else
+    {
+        __grow_by(__cap, __sz - __n1 + __n2 - __cap, __sz, __pos, __n1, __n2);
+        __p = _VSTD::__to_address(__get_long_pointer());
+    }
+    traits_type::assign(__p + __pos, __n2, __c);
+    __sz += __n2 - __n1;
+    __set_size(__sz);
+    __invalidate_iterators_past(__sz);
+    traits_type::assign(__p[__sz], value_type());
+    return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template<class _InputIterator>
+__enable_if_t
+<
+    __is_cpp17_input_iterator<_InputIterator>::value,
+    basic_string<_CharT, _Traits, _Allocator>&
+>
+basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2,
+                                                   _InputIterator __j1, _InputIterator __j2)
+{
+    const basic_string __temp(__j1, __j2, __alloc());
+    return this->replace(__i1, __i2, __temp);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos1, size_type __n1, const basic_string& __str)
+{
+    return replace(__pos1, __n1, __str.data(), __str.size());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos1, size_type __n1, const basic_string& __str,
+                                                   size_type __pos2, size_type __n2)
+{
+    size_type __str_sz = __str.size();
+    if (__pos2 > __str_sz)
+        this->__throw_out_of_range();
+    return replace(__pos1, __n1, __str.data() + __pos2, _VSTD::min(__n2, __str_sz - __pos2));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp>
+__enable_if_t
+<
+    __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value && !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
+    basic_string<_CharT, _Traits, _Allocator>&
+>
+basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos1, size_type __n1, const _Tp& __t,
+                                                   size_type __pos2, size_type __n2)
+{
+    __self_view __sv = __t;
+    size_type __str_sz = __sv.size();
+    if (__pos2 > __str_sz)
+        this->__throw_out_of_range();
+    return replace(__pos1, __n1, __sv.data() + __pos2, _VSTD::min(__n2, __str_sz - __pos2));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(size_type __pos, size_type __n1, const value_type* __s)
+{
+    _LIBCPP_ASSERT(__s != nullptr, "string::replace received nullptr");
+    return replace(__pos, __n1, __s, traits_type::length(__s));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, const basic_string& __str)
+{
+    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1),
+                   __str.data(), __str.size());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, const value_type* __s, size_type __n)
+{
+    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __s, __n);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, const value_type* __s)
+{
+    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __s);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::replace(const_iterator __i1, const_iterator __i2, size_type __n, value_type __c)
+{
+    return replace(static_cast<size_type>(__i1 - begin()), static_cast<size_type>(__i2 - __i1), __n, __c);
+}
+
+// erase
+
+// 'externally instantiated' erase() implementation, called when __n != npos.
+// Does not check __pos against size()
+template <class _CharT, class _Traits, class _Allocator>
+void
+basic_string<_CharT, _Traits, _Allocator>::__erase_external_with_move(
+    size_type __pos, size_type __n)
+{
+    if (__n)
+    {
+        size_type __sz = size();
+        value_type* __p = _VSTD::__to_address(__get_pointer());
+        __n = _VSTD::min(__n, __sz - __pos);
+        size_type __n_move = __sz - __pos - __n;
+        if (__n_move != 0)
+            traits_type::move(__p + __pos, __p + __pos + __n, __n_move);
+        __sz -= __n;
+        __set_size(__sz);
+        __invalidate_iterators_past(__sz);
+        traits_type::assign(__p[__sz], value_type());
+    }
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>&
+basic_string<_CharT, _Traits, _Allocator>::erase(size_type __pos,
+                                                 size_type __n) {
+  if (__pos > size()) this->__throw_out_of_range();
+  if (__n == npos) {
+    __erase_to_end(__pos);
+  } else {
+    __erase_external_with_move(__pos, __n);
+  }
+  return *this;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::iterator
+basic_string<_CharT, _Traits, _Allocator>::erase(const_iterator __pos)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__pos) == this,
+        "string::erase(iterator) called with an iterator not"
+        " referring to this string");
+#endif
+    _LIBCPP_ASSERT(__pos != end(),
+        "string::erase(iterator) called with a non-dereferenceable iterator");
+    iterator __b = begin();
+    size_type __r = static_cast<size_type>(__pos - __b);
+    erase(__r, 1);
+    return __b + static_cast<difference_type>(__r);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::iterator
+basic_string<_CharT, _Traits, _Allocator>::erase(const_iterator __first, const_iterator __last)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__first) == this,
+        "string::erase(iterator,  iterator) called with an iterator not"
+        " referring to this string");
+#endif
+    _LIBCPP_ASSERT(__first <= __last, "string::erase(first, last) called with invalid range");
+    iterator __b = begin();
+    size_type __r = static_cast<size_type>(__first - __b);
+    erase(__r, static_cast<size_type>(__last - __first));
+    return __b + static_cast<difference_type>(__r);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+void
+basic_string<_CharT, _Traits, _Allocator>::pop_back()
+{
+    _LIBCPP_ASSERT(!empty(), "string::pop_back(): string is already empty");
+    size_type __sz;
+    if (__is_long())
+    {
+        __sz = __get_long_size() - 1;
+        __set_long_size(__sz);
+        traits_type::assign(*(__get_long_pointer() + __sz), value_type());
+    }
+    else
+    {
+        __sz = __get_short_size() - 1;
+        __set_short_size(__sz);
+        traits_type::assign(*(__get_short_pointer() + __sz), value_type());
+    }
+    __invalidate_iterators_past(__sz);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+void
+basic_string<_CharT, _Traits, _Allocator>::clear() _NOEXCEPT
+{
+    __invalidate_all_iterators();
+    if (__is_long())
+    {
+        traits_type::assign(*__get_long_pointer(), value_type());
+        __set_long_size(0);
+    }
+    else
+    {
+        traits_type::assign(*__get_short_pointer(), value_type());
+        __set_short_size(0);
+    }
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+void
+basic_string<_CharT, _Traits, _Allocator>::__erase_to_end(size_type __pos)
+{
+    if (__is_long())
+    {
+        traits_type::assign(*(__get_long_pointer() + __pos), value_type());
+        __set_long_size(__pos);
+    }
+    else
+    {
+        traits_type::assign(*(__get_short_pointer() + __pos), value_type());
+        __set_short_size(__pos);
+    }
+    __invalidate_iterators_past(__pos);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+void
+basic_string<_CharT, _Traits, _Allocator>::resize(size_type __n, value_type __c)
+{
+    size_type __sz = size();
+    if (__n > __sz)
+        append(__n - __sz, __c);
+    else
+        __erase_to_end(__n);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline void
+basic_string<_CharT, _Traits, _Allocator>::__resize_default_init(size_type __n)
+{
+    size_type __sz = size();
+    if (__n > __sz) {
+       __append_default_init(__n - __sz);
+    } else
+        __erase_to_end(__n);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::max_size() const _NOEXCEPT
+{
+    size_type __m = __alloc_traits::max_size(__alloc());
+#ifdef _LIBCPP_BIG_ENDIAN
+    return (__m <= ~__long_mask ? __m : __m/2) - __alignment;
+#else
+    return __m - __alignment;
+#endif
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+void
+basic_string<_CharT, _Traits, _Allocator>::reserve(size_type __requested_capacity)
+{
+    if (__requested_capacity > max_size())
+        this->__throw_length_error();
+
+#if _LIBCPP_STD_VER > 17
+    // Reserve never shrinks as of C++20.
+    if (__requested_capacity <= capacity()) return;
+#endif
+
+    size_type __target_capacity = _VSTD::max(__requested_capacity, size());
+    __target_capacity = __recommend(__target_capacity);
+    if (__target_capacity == capacity()) return;
+
+    __shrink_or_extend(__target_capacity);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+void
+basic_string<_CharT, _Traits, _Allocator>::shrink_to_fit() _NOEXCEPT
+{
+    size_type __target_capacity = __recommend(size());
+    if (__target_capacity == capacity()) return;
+
+    __shrink_or_extend(__target_capacity);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+void
+basic_string<_CharT, _Traits, _Allocator>::__shrink_or_extend(size_type __target_capacity)
+{
+    size_type __cap = capacity();
+    size_type __sz = size();
+
+    pointer __new_data, __p;
+    bool __was_long, __now_long;
+    if (__target_capacity == __min_cap - 1)
+    {
+        __was_long = true;
+        __now_long = false;
+        __new_data = __get_short_pointer();
+        __p = __get_long_pointer();
+    }
+    else
+    {
+        if (__target_capacity > __cap)
+            __new_data = __alloc_traits::allocate(__alloc(), __target_capacity+1);
+        else
+        {
+        #ifndef _LIBCPP_NO_EXCEPTIONS
+            try
+            {
+        #endif // _LIBCPP_NO_EXCEPTIONS
+                __new_data = __alloc_traits::allocate(__alloc(), __target_capacity+1);
+        #ifndef _LIBCPP_NO_EXCEPTIONS
+            }
+            catch (...)
+            {
+                return;
+            }
+        #else  // _LIBCPP_NO_EXCEPTIONS
+            if (__new_data == nullptr)
+                return;
+        #endif // _LIBCPP_NO_EXCEPTIONS
+        }
+        __now_long = true;
+        __was_long = __is_long();
+        __p = __get_pointer();
+    }
+    traits_type::copy(_VSTD::__to_address(__new_data),
+                        _VSTD::__to_address(__p), size()+1);
+    if (__was_long)
+        __alloc_traits::deallocate(__alloc(), __p, __cap+1);
+    if (__now_long)
+    {
+        __set_long_cap(__target_capacity+1);
+        __set_long_size(__sz);
+        __set_long_pointer(__new_data);
+    }
+    else
+        __set_short_size(__sz);
+    __invalidate_all_iterators();
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::const_reference
+basic_string<_CharT, _Traits, _Allocator>::operator[](size_type __pos) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__pos <= size(), "string index out of bounds");
+    return *(data() + __pos);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::reference
+basic_string<_CharT, _Traits, _Allocator>::operator[](size_type __pos) _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__pos <= size(), "string index out of bounds");
+    return *(__get_pointer() + __pos);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+typename basic_string<_CharT, _Traits, _Allocator>::const_reference
+basic_string<_CharT, _Traits, _Allocator>::at(size_type __n) const
+{
+    if (__n >= size())
+        this->__throw_out_of_range();
+    return (*this)[__n];
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+typename basic_string<_CharT, _Traits, _Allocator>::reference
+basic_string<_CharT, _Traits, _Allocator>::at(size_type __n)
+{
+    if (__n >= size())
+        this->__throw_out_of_range();
+    return (*this)[__n];
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::reference
+basic_string<_CharT, _Traits, _Allocator>::front() _NOEXCEPT
+{
+    _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
+    return *__get_pointer();
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::const_reference
+basic_string<_CharT, _Traits, _Allocator>::front() const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(!empty(), "string::front(): string is empty");
+    return *data();
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::reference
+basic_string<_CharT, _Traits, _Allocator>::back() _NOEXCEPT
+{
+    _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
+    return *(__get_pointer() + size() - 1);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::const_reference
+basic_string<_CharT, _Traits, _Allocator>::back() const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(!empty(), "string::back(): string is empty");
+    return *(data() + size() - 1);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::copy(value_type* __s, size_type __n, size_type __pos) const
+{
+    size_type __sz = size();
+    if (__pos > __sz)
+        this->__throw_out_of_range();
+    size_type __rlen = _VSTD::min(__n, __sz - __pos);
+    traits_type::copy(__s, data() + __pos, __rlen);
+    return __rlen;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>
+basic_string<_CharT, _Traits, _Allocator>::substr(size_type __pos, size_type __n) const
+{
+    return basic_string(*this, __pos, __n, __alloc());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+void
+basic_string<_CharT, _Traits, _Allocator>::swap(basic_string& __str)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<allocator_type>::value)
+#endif
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    if (!__is_long())
+        __get_db()->__invalidate_all(this);
+    if (!__str.__is_long())
+        __get_db()->__invalidate_all(&__str);
+    __get_db()->swap(this, &__str);
+#endif
+    _LIBCPP_ASSERT(
+        __alloc_traits::propagate_on_container_swap::value ||
+        __alloc_traits::is_always_equal::value ||
+        __alloc() == __str.__alloc(), "swapping non-equal allocators");
+    _VSTD::swap(__r_.first(), __str.__r_.first());
+    _VSTD::__swap_allocator(__alloc(), __str.__alloc());
+}
+
+// find
+
+template <class _Traits>
+struct _LIBCPP_HIDDEN __traits_eq
+{
+    typedef typename _Traits::char_type char_type;
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const char_type& __x, const char_type& __y) _NOEXCEPT
+        {return _Traits::eq(__x, __y);}
+};
+
+template<class _CharT, class _Traits, class _Allocator>
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find(const value_type* __s,
+                                                size_type __pos,
+                                                size_type __n) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find(): received nullptr");
+    return __str_find<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, __n);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find(const basic_string& __str,
+                                                size_type __pos) const _NOEXCEPT
+{
+    return __str_find<value_type, size_type, traits_type, npos>
+        (data(), size(), __str.data(), __pos, __str.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+template <class _Tp>
+__enable_if_t
+<
+    __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type
+>
+basic_string<_CharT, _Traits, _Allocator>::find(const _Tp &__t,
+                                                size_type __pos) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    return __str_find<value_type, size_type, traits_type, npos>
+        (data(), size(), __sv.data(), __pos, __sv.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find(const value_type* __s,
+                                                size_type __pos) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__s != nullptr, "string::find(): received nullptr");
+    return __str_find<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, traits_type::length(__s));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find(value_type __c,
+                                                size_type __pos) const _NOEXCEPT
+{
+    return __str_find<value_type, size_type, traits_type, npos>
+        (data(), size(), __c, __pos);
+}
+
+// rfind
+
+template<class _CharT, class _Traits, class _Allocator>
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::rfind(const value_type* __s,
+                                                 size_type __pos,
+                                                 size_type __n) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::rfind(): received nullptr");
+    return __str_rfind<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, __n);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::rfind(const basic_string& __str,
+                                                 size_type __pos) const _NOEXCEPT
+{
+    return __str_rfind<value_type, size_type, traits_type, npos>
+        (data(), size(), __str.data(), __pos, __str.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+template <class _Tp>
+__enable_if_t
+<
+    __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type
+>
+basic_string<_CharT, _Traits, _Allocator>::rfind(const _Tp& __t,
+                                                size_type __pos) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    return __str_rfind<value_type, size_type, traits_type, npos>
+        (data(), size(), __sv.data(), __pos, __sv.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::rfind(const value_type* __s,
+                                                 size_type __pos) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__s != nullptr, "string::rfind(): received nullptr");
+    return __str_rfind<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, traits_type::length(__s));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::rfind(value_type __c,
+                                                 size_type __pos) const _NOEXCEPT
+{
+    return __str_rfind<value_type, size_type, traits_type, npos>
+        (data(), size(), __c, __pos);
+}
+
+// find_first_of
+
+template<class _CharT, class _Traits, class _Allocator>
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_of(const value_type* __s,
+                                                         size_type __pos,
+                                                         size_type __n) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_first_of(): received nullptr");
+    return __str_find_first_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, __n);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_of(const basic_string& __str,
+                                                         size_type __pos) const _NOEXCEPT
+{
+    return __str_find_first_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __str.data(), __pos, __str.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+template <class _Tp>
+__enable_if_t
+<
+    __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type
+>
+basic_string<_CharT, _Traits, _Allocator>::find_first_of(const _Tp& __t,
+                                                size_type __pos) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    return __str_find_first_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __sv.data(), __pos, __sv.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_of(const value_type* __s,
+                                                         size_type __pos) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__s != nullptr, "string::find_first_of(): received nullptr");
+    return __str_find_first_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, traits_type::length(__s));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_of(value_type __c,
+                                                         size_type __pos) const _NOEXCEPT
+{
+    return find(__c, __pos);
+}
+
+// find_last_of
+
+template<class _CharT, class _Traits, class _Allocator>
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_of(const value_type* __s,
+                                                        size_type __pos,
+                                                        size_type __n) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_last_of(): received nullptr");
+    return __str_find_last_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, __n);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_of(const basic_string& __str,
+                                                        size_type __pos) const _NOEXCEPT
+{
+    return __str_find_last_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __str.data(), __pos, __str.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+template <class _Tp>
+__enable_if_t
+<
+    __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type
+>
+basic_string<_CharT, _Traits, _Allocator>::find_last_of(const _Tp& __t,
+                                                size_type __pos) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    return __str_find_last_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __sv.data(), __pos, __sv.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_of(const value_type* __s,
+                                                        size_type __pos) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__s != nullptr, "string::find_last_of(): received nullptr");
+    return __str_find_last_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, traits_type::length(__s));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_of(value_type __c,
+                                                        size_type __pos) const _NOEXCEPT
+{
+    return rfind(__c, __pos);
+}
+
+// find_first_not_of
+
+template<class _CharT, class _Traits, class _Allocator>
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const value_type* __s,
+                                                             size_type __pos,
+                                                             size_type __n) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_first_not_of(): received nullptr");
+    return __str_find_first_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, __n);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const basic_string& __str,
+                                                             size_type __pos) const _NOEXCEPT
+{
+    return __str_find_first_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __str.data(), __pos, __str.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+template <class _Tp>
+__enable_if_t
+<
+    __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type
+>
+basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const _Tp& __t,
+                                                size_type __pos) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    return __str_find_first_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __sv.data(), __pos, __sv.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(const value_type* __s,
+                                                             size_type __pos) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__s != nullptr, "string::find_first_not_of(): received nullptr");
+    return __str_find_first_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, traits_type::length(__s));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_first_not_of(value_type __c,
+                                                             size_type __pos) const _NOEXCEPT
+{
+    return __str_find_first_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __c, __pos);
+}
+
+// find_last_not_of
+
+template<class _CharT, class _Traits, class _Allocator>
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const value_type* __s,
+                                                            size_type __pos,
+                                                            size_type __n) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string::find_last_not_of(): received nullptr");
+    return __str_find_last_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, __n);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const basic_string& __str,
+                                                            size_type __pos) const _NOEXCEPT
+{
+    return __str_find_last_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __str.data(), __pos, __str.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+template <class _Tp>
+__enable_if_t
+<
+    __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type
+>
+basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const _Tp& __t,
+                                                size_type __pos) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    return __str_find_last_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __sv.data(), __pos, __sv.size());
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(const value_type* __s,
+                                                            size_type __pos) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__s != nullptr, "string::find_last_not_of(): received nullptr");
+    return __str_find_last_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __s, __pos, traits_type::length(__s));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+typename basic_string<_CharT, _Traits, _Allocator>::size_type
+basic_string<_CharT, _Traits, _Allocator>::find_last_not_of(value_type __c,
+                                                            size_type __pos) const _NOEXCEPT
+{
+    return __str_find_last_not_of<value_type, size_type, traits_type, npos>
+        (data(), size(), __c, __pos);
+}
+
+// compare
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp>
+__enable_if_t
+<
+    __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+    int
+>
+basic_string<_CharT, _Traits, _Allocator>::compare(const _Tp& __t) const _NOEXCEPT
+{
+    __self_view __sv = __t;
+    size_t __lhs_sz = size();
+    size_t __rhs_sz = __sv.size();
+    int __result = traits_type::compare(data(), __sv.data(),
+                                        _VSTD::min(__lhs_sz, __rhs_sz));
+    if (__result != 0)
+        return __result;
+    if (__lhs_sz < __rhs_sz)
+        return -1;
+    if (__lhs_sz > __rhs_sz)
+        return 1;
+    return 0;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+int
+basic_string<_CharT, _Traits, _Allocator>::compare(const basic_string& __str) const _NOEXCEPT
+{
+    return compare(__self_view(__str));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+int
+basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
+                                                   size_type __n1,
+                                                   const value_type* __s,
+                                                   size_type __n2) const
+{
+    _LIBCPP_ASSERT(__n2 == 0 || __s != nullptr, "string::compare(): received nullptr");
+    size_type __sz = size();
+    if (__pos1 > __sz || __n2 == npos)
+        this->__throw_out_of_range();
+    size_type __rlen = _VSTD::min(__n1, __sz - __pos1);
+    int __r = traits_type::compare(data() + __pos1, __s, _VSTD::min(__rlen, __n2));
+    if (__r == 0)
+    {
+        if (__rlen < __n2)
+            __r = -1;
+        else if (__rlen > __n2)
+            __r = 1;
+    }
+    return __r;
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp>
+__enable_if_t
+<
+    __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value,
+    int
+>
+basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
+                                                   size_type __n1,
+                                                   const _Tp& __t) const
+{
+    __self_view __sv = __t;
+    return compare(__pos1, __n1, __sv.data(), __sv.size());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+inline
+int
+basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
+                                                   size_type __n1,
+                                                   const basic_string& __str) const
+{
+    return compare(__pos1, __n1, __str.data(), __str.size());
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+template <class _Tp>
+__enable_if_t
+<
+    __can_be_converted_to_string_view<_CharT, _Traits, _Tp>::value
+    && !__is_same_uncvref<_Tp, basic_string<_CharT, _Traits, _Allocator> >::value,
+    int
+>
+basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
+                                                   size_type __n1,
+                                                   const _Tp& __t,
+                                                   size_type __pos2,
+                                                   size_type __n2) const
+{
+    __self_view __sv = __t;
+    return __self_view(*this).substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+int
+basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
+                                                   size_type __n1,
+                                                   const basic_string& __str,
+                                                   size_type __pos2,
+                                                   size_type __n2) const
+{
+        return compare(__pos1, __n1, __self_view(__str), __pos2, __n2);
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+int
+basic_string<_CharT, _Traits, _Allocator>::compare(const value_type* __s) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__s != nullptr, "string::compare(): received nullptr");
+    return compare(0, npos, __s, traits_type::length(__s));
+}
+
+template <class _CharT, class _Traits, class _Allocator>
+int
+basic_string<_CharT, _Traits, _Allocator>::compare(size_type __pos1,
+                                                   size_type __n1,
+                                                   const value_type* __s) const
+{
+    _LIBCPP_ASSERT(__s != nullptr, "string::compare(): received nullptr");
+    return compare(__pos1, __n1, __s, traits_type::length(__s));
+}
+
+// __invariants
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+bool
+basic_string<_CharT, _Traits, _Allocator>::__invariants() const
+{
+    if (size() > capacity())
+        return false;
+    if (capacity() < __min_cap - 1)
+        return false;
+    if (data() == nullptr)
+        return false;
+    if (data()[size()] != value_type())
+        return false;
+    return true;
+}
+
+// __clear_and_shrink
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+void
+basic_string<_CharT, _Traits, _Allocator>::__clear_and_shrink() _NOEXCEPT
+{
+    clear();
+    if(__is_long())
+    {
+        __alloc_traits::deallocate(__alloc(), __get_long_pointer(), capacity() + 1);
+        __set_long_cap(0);
+        __set_short_size(0);
+        traits_type::assign(*__get_short_pointer(), value_type());
+    }
+}
+
+// operator==
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    size_t __lhs_sz = __lhs.size();
+    return __lhs_sz == __rhs.size() && _Traits::compare(__lhs.data(),
+                                                        __rhs.data(),
+                                                        __lhs_sz) == 0;
+}
+
+template<class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const basic_string<char, char_traits<char>, _Allocator>& __lhs,
+           const basic_string<char, char_traits<char>, _Allocator>& __rhs) _NOEXCEPT
+{
+    size_t __lhs_sz = __lhs.size();
+    if (__lhs_sz != __rhs.size())
+        return false;
+    const char* __lp = __lhs.data();
+    const char* __rp = __rhs.data();
+    if (__lhs.__is_long())
+        return char_traits<char>::compare(__lp, __rp, __lhs_sz) == 0;
+    for (; __lhs_sz != 0; --__lhs_sz, ++__lp, ++__rp)
+        if (*__lp != *__rp)
+            return false;
+    return true;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const _CharT* __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    typedef basic_string<_CharT, _Traits, _Allocator> _String;
+    _LIBCPP_ASSERT(__lhs != nullptr, "operator==(char*, basic_string): received nullptr");
+    size_t __lhs_len = _Traits::length(__lhs);
+    if (__lhs_len != __rhs.size()) return false;
+    return __rhs.compare(0, _String::npos, __lhs, __lhs_len) == 0;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const basic_string<_CharT,_Traits,_Allocator>& __lhs,
+           const _CharT* __rhs) _NOEXCEPT
+{
+    typedef basic_string<_CharT, _Traits, _Allocator> _String;
+    _LIBCPP_ASSERT(__rhs != nullptr, "operator==(basic_string, char*): received nullptr");
+    size_t __rhs_len = _Traits::length(__rhs);
+    if (__rhs_len != __lhs.size()) return false;
+    return __lhs.compare(0, _String::npos, __rhs, __rhs_len) == 0;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const basic_string<_CharT,_Traits,_Allocator>& __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return !(__lhs == __rhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const _CharT* __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return !(__lhs == __rhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const _CharT* __rhs) _NOEXCEPT
+{
+    return !(__lhs == __rhs);
+}
+
+// operator<
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) < 0;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const _CharT* __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) < 0;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const _CharT* __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return __rhs.compare(__lhs) > 0;
+}
+
+// operator>
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return __rhs < __lhs;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const _CharT* __rhs) _NOEXCEPT
+{
+    return __rhs < __lhs;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const _CharT* __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return __rhs < __lhs;
+}
+
+// operator<=
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return !(__rhs < __lhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const _CharT* __rhs) _NOEXCEPT
+{
+    return !(__rhs < __lhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const _CharT* __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return !(__rhs < __lhs);
+}
+
+// operator>=
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return !(__lhs < __rhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+           const _CharT* __rhs) _NOEXCEPT
+{
+    return !(__lhs < __rhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const _CharT* __lhs,
+           const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
+{
+    return !(__lhs < __rhs);
+}
+
+// operator +
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
+          const basic_string<_CharT, _Traits, _Allocator>& __rhs)
+{
+    basic_string<_CharT, _Traits, _Allocator> __r(__lhs.get_allocator());
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = __lhs.size();
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = __rhs.size();
+    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + __rhs_sz);
+    __r.append(__rhs.data(), __rhs_sz);
+    return __r;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const _CharT* __lhs , const basic_string<_CharT,_Traits,_Allocator>& __rhs)
+{
+    basic_string<_CharT, _Traits, _Allocator> __r(__rhs.get_allocator());
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = _Traits::length(__lhs);
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = __rhs.size();
+    __r.__init(__lhs, __lhs_sz, __lhs_sz + __rhs_sz);
+    __r.append(__rhs.data(), __rhs_sz);
+    return __r;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>
+operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Allocator>& __rhs)
+{
+    basic_string<_CharT, _Traits, _Allocator> __r(__rhs.get_allocator());
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = __rhs.size();
+    __r.__init(&__lhs, 1, 1 + __rhs_sz);
+    __r.append(__rhs.data(), __rhs_sz);
+    return __r;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, const _CharT* __rhs)
+{
+    basic_string<_CharT, _Traits, _Allocator> __r(__lhs.get_allocator());
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = __lhs.size();
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type __rhs_sz = _Traits::length(__rhs);
+    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + __rhs_sz);
+    __r.append(__rhs, __rhs_sz);
+    return __r;
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, _CharT __rhs)
+{
+    basic_string<_CharT, _Traits, _Allocator> __r(__lhs.get_allocator());
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type __lhs_sz = __lhs.size();
+    __r.__init(__lhs.data(), __lhs_sz, __lhs_sz + 1);
+    __r.push_back(__rhs);
+    return __r;
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_string<_CharT, _Traits, _Allocator>
+operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, const basic_string<_CharT, _Traits, _Allocator>& __rhs)
+{
+    return _VSTD::move(__lhs.append(__rhs));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const basic_string<_CharT, _Traits, _Allocator>& __lhs, basic_string<_CharT, _Traits, _Allocator>&& __rhs)
+{
+    return _VSTD::move(__rhs.insert(0, __lhs));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_string<_CharT, _Traits, _Allocator>
+operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, basic_string<_CharT, _Traits, _Allocator>&& __rhs)
+{
+    return _VSTD::move(__lhs.append(__rhs));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_string<_CharT, _Traits, _Allocator>
+operator+(const _CharT* __lhs , basic_string<_CharT,_Traits,_Allocator>&& __rhs)
+{
+    return _VSTD::move(__rhs.insert(0, __lhs));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_string<_CharT, _Traits, _Allocator>
+operator+(_CharT __lhs, basic_string<_CharT,_Traits,_Allocator>&& __rhs)
+{
+    __rhs.insert(__rhs.begin(), __lhs);
+    return _VSTD::move(__rhs);
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_string<_CharT, _Traits, _Allocator>
+operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, const _CharT* __rhs)
+{
+    return _VSTD::move(__lhs.append(__rhs));
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_string<_CharT, _Traits, _Allocator>
+operator+(basic_string<_CharT, _Traits, _Allocator>&& __lhs, _CharT __rhs)
+{
+    __lhs.push_back(__rhs);
+    return _VSTD::move(__lhs);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+// swap
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(basic_string<_CharT, _Traits, _Allocator>& __lhs,
+     basic_string<_CharT, _Traits, _Allocator>& __rhs)
+     _NOEXCEPT_(_NOEXCEPT_(__lhs.swap(__rhs)))
+{
+    __lhs.swap(__rhs);
+}
+
+_LIBCPP_FUNC_VIS int                stoi  (const string& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_FUNC_VIS long               stol  (const string& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_FUNC_VIS unsigned long      stoul (const string& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_FUNC_VIS long long          stoll (const string& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_FUNC_VIS unsigned long long stoull(const string& __str, size_t* __idx = nullptr, int __base = 10);
+
+_LIBCPP_FUNC_VIS float       stof (const string& __str, size_t* __idx = nullptr);
+_LIBCPP_FUNC_VIS double      stod (const string& __str, size_t* __idx = nullptr);
+_LIBCPP_FUNC_VIS long double stold(const string& __str, size_t* __idx = nullptr);
+
+_LIBCPP_FUNC_VIS string to_string(int __val);
+_LIBCPP_FUNC_VIS string to_string(unsigned __val);
+_LIBCPP_FUNC_VIS string to_string(long __val);
+_LIBCPP_FUNC_VIS string to_string(unsigned long __val);
+_LIBCPP_FUNC_VIS string to_string(long long __val);
+_LIBCPP_FUNC_VIS string to_string(unsigned long long __val);
+_LIBCPP_FUNC_VIS string to_string(float __val);
+_LIBCPP_FUNC_VIS string to_string(double __val);
+_LIBCPP_FUNC_VIS string to_string(long double __val);
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+_LIBCPP_FUNC_VIS int                stoi  (const wstring& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_FUNC_VIS long               stol  (const wstring& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_FUNC_VIS unsigned long      stoul (const wstring& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_FUNC_VIS long long          stoll (const wstring& __str, size_t* __idx = nullptr, int __base = 10);
+_LIBCPP_FUNC_VIS unsigned long long stoull(const wstring& __str, size_t* __idx = nullptr, int __base = 10);
+
+_LIBCPP_FUNC_VIS float       stof (const wstring& __str, size_t* __idx = nullptr);
+_LIBCPP_FUNC_VIS double      stod (const wstring& __str, size_t* __idx = nullptr);
+_LIBCPP_FUNC_VIS long double stold(const wstring& __str, size_t* __idx = nullptr);
+
+_LIBCPP_FUNC_VIS wstring to_wstring(int __val);
+_LIBCPP_FUNC_VIS wstring to_wstring(unsigned __val);
+_LIBCPP_FUNC_VIS wstring to_wstring(long __val);
+_LIBCPP_FUNC_VIS wstring to_wstring(unsigned long __val);
+_LIBCPP_FUNC_VIS wstring to_wstring(long long __val);
+_LIBCPP_FUNC_VIS wstring to_wstring(unsigned long long __val);
+_LIBCPP_FUNC_VIS wstring to_wstring(float __val);
+_LIBCPP_FUNC_VIS wstring to_wstring(double __val);
+_LIBCPP_FUNC_VIS wstring to_wstring(long double __val);
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+template<class _CharT, class _Traits, class _Allocator>
+_LIBCPP_TEMPLATE_DATA_VIS
+const typename basic_string<_CharT, _Traits, _Allocator>::size_type
+               basic_string<_CharT, _Traits, _Allocator>::npos;
+
+template <class _CharT, class _Allocator>
+struct _LIBCPP_TEMPLATE_VIS
+    hash<basic_string<_CharT, char_traits<_CharT>, _Allocator> >
+    : public unary_function<
+          basic_string<_CharT, char_traits<_CharT>, _Allocator>, size_t>
+{
+    size_t
+    operator()(const basic_string<_CharT, char_traits<_CharT>, _Allocator>& __val) const _NOEXCEPT
+    { return __do_string_hash(__val.data(), __val.data() + __val.size()); }
+};
+
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           const basic_string<_CharT, _Traits, _Allocator>& __str);
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is,
+           basic_string<_CharT, _Traits, _Allocator>& __str);
+
+template<class _CharT, class _Traits, class _Allocator>
+basic_istream<_CharT, _Traits>&
+getline(basic_istream<_CharT, _Traits>& __is,
+        basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm);
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<_CharT, _Traits>&
+getline(basic_istream<_CharT, _Traits>& __is,
+        basic_string<_CharT, _Traits, _Allocator>& __str);
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<_CharT, _Traits>&
+getline(basic_istream<_CharT, _Traits>&& __is,
+        basic_string<_CharT, _Traits, _Allocator>& __str, _CharT __dlm);
+
+template<class _CharT, class _Traits, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+basic_istream<_CharT, _Traits>&
+getline(basic_istream<_CharT, _Traits>&& __is,
+        basic_string<_CharT, _Traits, _Allocator>& __str);
+
+#if _LIBCPP_STD_VER > 17
+template <class _CharT, class _Traits, class _Allocator, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type
+    erase(basic_string<_CharT, _Traits, _Allocator>& __str, const _Up& __v) {
+  auto __old_size = __str.size();
+  __str.erase(_VSTD::remove(__str.begin(), __str.end(), __v), __str.end());
+  return __old_size - __str.size();
+}
+
+template <class _CharT, class _Traits, class _Allocator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+    typename basic_string<_CharT, _Traits, _Allocator>::size_type
+    erase_if(basic_string<_CharT, _Traits, _Allocator>& __str,
+             _Predicate __pred) {
+  auto __old_size = __str.size();
+  __str.erase(_VSTD::remove_if(__str.begin(), __str.end(), __pred),
+              __str.end());
+  return __old_size - __str.size();
+}
+#endif
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+template<class _CharT, class _Traits, class _Allocator>
+bool
+basic_string<_CharT, _Traits, _Allocator>::__dereferenceable(const const_iterator* __i) const
+{
+    return this->data() <= _VSTD::__to_address(__i->base()) &&
+           _VSTD::__to_address(__i->base()) < this->data() + this->size();
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+bool
+basic_string<_CharT, _Traits, _Allocator>::__decrementable(const const_iterator* __i) const
+{
+    return this->data() < _VSTD::__to_address(__i->base()) &&
+           _VSTD::__to_address(__i->base()) <= this->data() + this->size();
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+bool
+basic_string<_CharT, _Traits, _Allocator>::__addable(const const_iterator* __i, ptrdiff_t __n) const
+{
+    const value_type* __p = _VSTD::__to_address(__i->base()) + __n;
+    return this->data() <= __p && __p <= this->data() + this->size();
+}
+
+template<class _CharT, class _Traits, class _Allocator>
+bool
+basic_string<_CharT, _Traits, _Allocator>::__subscriptable(const const_iterator* __i, ptrdiff_t __n) const
+{
+    const value_type* __p = _VSTD::__to_address(__i->base()) + __n;
+    return this->data() <= __p && __p < this->data() + this->size();
+}
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+#if _LIBCPP_STD_VER > 11
+// Literal suffixes for basic_string [basic.string.literals]
+inline namespace literals
+{
+  inline namespace string_literals
+  {
+    inline _LIBCPP_INLINE_VISIBILITY
+    basic_string<char> operator "" s( const char *__str, size_t __len )
+    {
+        return basic_string<char> (__str, __len);
+    }
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    inline _LIBCPP_INLINE_VISIBILITY
+    basic_string<wchar_t> operator "" s( const wchar_t *__str, size_t __len )
+    {
+        return basic_string<wchar_t> (__str, __len);
+    }
+#endif
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+    inline _LIBCPP_INLINE_VISIBILITY
+    basic_string<char8_t> operator "" s(const char8_t *__str, size_t __len) _NOEXCEPT
+    {
+        return basic_string<char8_t> (__str, __len);
+    }
+#endif
+
+    inline _LIBCPP_INLINE_VISIBILITY
+    basic_string<char16_t> operator "" s( const char16_t *__str, size_t __len )
+    {
+        return basic_string<char16_t> (__str, __len);
+    }
+
+    inline _LIBCPP_INLINE_VISIBILITY
+    basic_string<char32_t> operator "" s( const char32_t *__str, size_t __len )
+    {
+        return basic_string<char32_t> (__str, __len);
+    }
+  }
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_STRING
diff --git a/contrib/libs/cxxsupp/libcxx/include/string.h b/contrib/libs/cxxsupp/libcxx/include/string.h
new file mode 100644
index 00000000000..e12f5895b8b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/string.h
@@ -0,0 +1,113 @@
+// -*- C++ -*-
+//===--------------------------- string.h ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_STRING_H
+#define _LIBCPP_STRING_H
+
+/*
+    string.h synopsis
+
+Macros:
+
+    NULL
+
+Types:
+
+    size_t
+
+void* memcpy(void* restrict s1, const void* restrict s2, size_t n);
+void* memmove(void* s1, const void* s2, size_t n);
+char* strcpy (char* restrict s1, const char* restrict s2);
+char* strncpy(char* restrict s1, const char* restrict s2, size_t n);
+char* strcat (char* restrict s1, const char* restrict s2);
+char* strncat(char* restrict s1, const char* restrict s2, size_t n);
+int memcmp(const void* s1, const void* s2, size_t n);
+int strcmp (const char* s1, const char* s2);
+int strncmp(const char* s1, const char* s2, size_t n);
+int strcoll(const char* s1, const char* s2);
+size_t strxfrm(char* restrict s1, const char* restrict s2, size_t n);
+const void* memchr(const void* s, int c, size_t n);
+      void* memchr(      void* s, int c, size_t n);
+const char* strchr(const char* s, int c);
+      char* strchr(      char* s, int c);
+size_t strcspn(const char* s1, const char* s2);
+const char* strpbrk(const char* s1, const char* s2);
+      char* strpbrk(      char* s1, const char* s2);
+const char* strrchr(const char* s, int c);
+      char* strrchr(      char* s, int c);
+size_t strspn(const char* s1, const char* s2);
+const char* strstr(const char* s1, const char* s2);
+      char* strstr(      char* s1, const char* s2);
+char* strtok(char* restrict s1, const char* restrict s2);
+void* memset(void* s, int c, size_t n);
+char* strerror(int errnum);
+size_t strlen(const char* s);
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(string.h)
+#else
+#include_next <string.h>
+#endif
+
+// MSVCRT, GNU libc and its derivates may already have the correct prototype in
+// <string.h>. This macro can be defined by users if their C library provides
+// the right signature.
+#if defined(__CORRECT_ISO_CPP_STRING_H_PROTO) || defined(_LIBCPP_MSVCRT) || \
+    defined(__sun__) || defined(_STRING_H_CPLUSPLUS_98_CONFORMANCE_)
+#define _LIBCPP_STRING_H_HAS_CONST_OVERLOADS
+#endif
+
+#if defined(__cplusplus) && !defined(_LIBCPP_STRING_H_HAS_CONST_OVERLOADS) && defined(_LIBCPP_PREFERRED_OVERLOAD)
+extern "C++" {
+inline _LIBCPP_INLINE_VISIBILITY
+char* __libcpp_strchr(const char* __s, int __c) {return (char*)strchr(__s, __c);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+const char* strchr(const char* __s, int __c) {return __libcpp_strchr(__s, __c);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+      char* strchr(      char* __s, int __c) {return __libcpp_strchr(__s, __c);}
+
+inline _LIBCPP_INLINE_VISIBILITY
+char* __libcpp_strpbrk(const char* __s1, const char* __s2) {return (char*)strpbrk(__s1, __s2);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+const char* strpbrk(const char* __s1, const char* __s2) {return __libcpp_strpbrk(__s1, __s2);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+      char* strpbrk(      char* __s1, const char* __s2) {return __libcpp_strpbrk(__s1, __s2);}
+
+inline _LIBCPP_INLINE_VISIBILITY
+char* __libcpp_strrchr(const char* __s, int __c) {return (char*)strrchr(__s, __c);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+const char* strrchr(const char* __s, int __c) {return __libcpp_strrchr(__s, __c);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+      char* strrchr(      char* __s, int __c) {return __libcpp_strrchr(__s, __c);}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void* __libcpp_memchr(const void* __s, int __c, size_t __n) {return (void*)memchr(__s, __c, __n);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+const void* memchr(const void* __s, int __c, size_t __n) {return __libcpp_memchr(__s, __c, __n);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+      void* memchr(      void* __s, int __c, size_t __n) {return __libcpp_memchr(__s, __c, __n);}
+
+inline _LIBCPP_INLINE_VISIBILITY
+char* __libcpp_strstr(const char* __s1, const char* __s2) {return (char*)strstr(__s1, __s2);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+const char* strstr(const char* __s1, const char* __s2) {return __libcpp_strstr(__s1, __s2);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+      char* strstr(      char* __s1, const char* __s2) {return __libcpp_strstr(__s1, __s2);}
+}
+#endif
+
+#endif // _LIBCPP_STRING_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/string_view b/contrib/libs/cxxsupp/libcxx/include/string_view
new file mode 100644
index 00000000000..8df3ff297c5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/string_view
@@ -0,0 +1,992 @@
+// -*- C++ -*-
+//===------------------------ string_view ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_STRING_VIEW
+#define _LIBCPP_STRING_VIEW
+
+/*
+string_view synopsis
+
+namespace std {
+
+    // 7.2, Class template basic_string_view
+    template<class charT, class traits = char_traits<charT>>
+        class basic_string_view;
+
+    template<class charT, class traits>
+    inline constexpr bool ranges::enable_view<basic_string_view<charT, traits>> = true;
+
+    template<class charT, class traits>
+    inline constexpr bool ranges::enable_borrowed_range<basic_string_view<charT, traits>> = true;  // C++20
+
+    // 7.9, basic_string_view non-member comparison functions
+    template<class charT, class traits>
+    constexpr bool operator==(basic_string_view<charT, traits> x,
+                              basic_string_view<charT, traits> y) noexcept;
+    template<class charT, class traits>
+    constexpr bool operator!=(basic_string_view<charT, traits> x,
+                              basic_string_view<charT, traits> y) noexcept;
+    template<class charT, class traits>
+    constexpr bool operator< (basic_string_view<charT, traits> x,
+                                 basic_string_view<charT, traits> y) noexcept;
+    template<class charT, class traits>
+    constexpr bool operator> (basic_string_view<charT, traits> x,
+                              basic_string_view<charT, traits> y) noexcept;
+    template<class charT, class traits>
+    constexpr bool operator<=(basic_string_view<charT, traits> x,
+                                 basic_string_view<charT, traits> y) noexcept;
+    template<class charT, class traits>
+    constexpr bool operator>=(basic_string_view<charT, traits> x,
+                              basic_string_view<charT, traits> y) noexcept;
+    // see below, sufficient additional overloads of comparison functions
+
+    // 7.10, Inserters and extractors
+    template<class charT, class traits>
+      basic_ostream<charT, traits>&
+        operator<<(basic_ostream<charT, traits>& os,
+                   basic_string_view<charT, traits> str);
+
+    // basic_string_view typedef names
+    typedef basic_string_view<char> string_view;
+    typedef basic_string_view<char8_t> u8string_view; // C++20
+    typedef basic_string_view<char16_t> u16string_view;
+    typedef basic_string_view<char32_t> u32string_view;
+    typedef basic_string_view<wchar_t> wstring_view;
+
+    template<class charT, class traits = char_traits<charT>>
+    class basic_string_view {
+      public:
+      // types
+      typedef traits traits_type;
+      typedef charT value_type;
+      typedef charT* pointer;
+      typedef const charT* const_pointer;
+      typedef charT& reference;
+      typedef const charT& const_reference;
+      typedef implementation-defined const_iterator;
+      typedef const_iterator iterator;
+      typedef reverse_iterator<const_iterator> const_reverse_iterator;
+      typedef const_reverse_iterator reverse_iterator;
+      typedef size_t size_type;
+      typedef ptrdiff_t difference_type;
+      static constexpr size_type npos = size_type(-1);
+
+      // 7.3, basic_string_view constructors and assignment operators
+      constexpr basic_string_view() noexcept;
+      constexpr basic_string_view(const basic_string_view&) noexcept = default;
+      basic_string_view& operator=(const basic_string_view&) noexcept = default;
+      template<class Allocator>
+      constexpr basic_string_view(const charT* str);
+      basic_string_view(nullptr_t) = delete; // C++2b
+      constexpr basic_string_view(const charT* str, size_type len);
+      template <class It, class End>
+      constexpr basic_string_view(It begin, End end); // C++20
+
+      // 7.4, basic_string_view iterator support
+      constexpr const_iterator begin() const noexcept;
+      constexpr const_iterator end() const noexcept;
+      constexpr const_iterator cbegin() const noexcept;
+      constexpr const_iterator cend() const noexcept;
+      const_reverse_iterator rbegin() const noexcept;
+      const_reverse_iterator rend() const noexcept;
+      const_reverse_iterator crbegin() const noexcept;
+      const_reverse_iterator crend() const noexcept;
+
+      // 7.5, basic_string_view capacity
+      constexpr size_type size() const noexcept;
+      constexpr size_type length() const noexcept;
+      constexpr size_type max_size() const noexcept;
+      constexpr bool empty() const noexcept;
+
+      // 7.6, basic_string_view element access
+      constexpr const_reference operator[](size_type pos) const;
+      constexpr const_reference at(size_type pos) const;
+      constexpr const_reference front() const;
+      constexpr const_reference back() const;
+      constexpr const_pointer data() const noexcept;
+
+      // 7.7, basic_string_view modifiers
+      constexpr void remove_prefix(size_type n);
+      constexpr void remove_suffix(size_type n);
+      constexpr void swap(basic_string_view& s) noexcept;
+
+      size_type copy(charT* s, size_type n, size_type pos = 0) const;  // constexpr in C++20
+
+      constexpr basic_string_view substr(size_type pos = 0, size_type n = npos) const;
+      constexpr int compare(basic_string_view s) const noexcept;
+      constexpr int compare(size_type pos1, size_type n1, basic_string_view s) const;
+      constexpr int compare(size_type pos1, size_type n1,
+                            basic_string_view s, size_type pos2, size_type n2) const;
+      constexpr int compare(const charT* s) const;
+      constexpr int compare(size_type pos1, size_type n1, const charT* s) const;
+      constexpr int compare(size_type pos1, size_type n1,
+                            const charT* s, size_type n2) const;
+      constexpr size_type find(basic_string_view s, size_type pos = 0) const noexcept;
+      constexpr size_type find(charT c, size_type pos = 0) const noexcept;
+      constexpr size_type find(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
+      constexpr size_type find(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
+      constexpr size_type rfind(basic_string_view s, size_type pos = npos) const noexcept;
+      constexpr size_type rfind(charT c, size_type pos = npos) const noexcept;
+      constexpr size_type rfind(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
+      constexpr size_type rfind(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
+      constexpr size_type find_first_of(basic_string_view s, size_type pos = 0) const noexcept;
+      constexpr size_type find_first_of(charT c, size_type pos = 0) const noexcept;
+      constexpr size_type find_first_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
+      constexpr size_type find_first_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
+      constexpr size_type find_last_of(basic_string_view s, size_type pos = npos) const noexcept;
+      constexpr size_type find_last_of(charT c, size_type pos = npos) const noexcept;
+      constexpr size_type find_last_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
+      constexpr size_type find_last_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
+      constexpr size_type find_first_not_of(basic_string_view s, size_type pos = 0) const noexcept;
+      constexpr size_type find_first_not_of(charT c, size_type pos = 0) const noexcept;
+      constexpr size_type find_first_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
+      constexpr size_type find_first_not_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
+      constexpr size_type find_last_not_of(basic_string_view s, size_type pos = npos) const noexcept;
+      constexpr size_type find_last_not_of(charT c, size_type pos = npos) const noexcept;
+      constexpr size_type find_last_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
+      constexpr size_type find_last_not_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
+
+      constexpr bool starts_with(basic_string_view s) const noexcept; // C++20
+      constexpr bool starts_with(charT c) const noexcept;             // C++20
+      constexpr bool starts_with(const charT* s) const;               // C++20
+      constexpr bool ends_with(basic_string_view s) const noexcept;   // C++20
+      constexpr bool ends_with(charT c) const noexcept;               // C++20
+      constexpr bool ends_with(const charT* s) const;                 // C++20
+
+      constexpr bool contains(basic_string_view s) const noexcept; // C++2b
+      constexpr bool contains(charT c) const noexcept;             // C++2b
+      constexpr bool contains(const charT* s) const;               // C++2b
+
+     private:
+      const_pointer data_;  // exposition only
+      size_type     size_;  // exposition only
+    };
+
+  // basic_string_view deduction guides
+  template<class It, class End>
+    basic_string_view(It, End) -> basic_string_view<iter_value_t<It>>; // C++20
+
+  // 7.11, Hash support
+  template <class T> struct hash;
+  template <> struct hash<string_view>;
+  template <> struct hash<u8string_view>; // C++20
+  template <> struct hash<u16string_view>;
+  template <> struct hash<u32string_view>;
+  template <> struct hash<wstring_view>;
+
+  constexpr basic_string_view<char>     operator "" sv( const char *str,     size_t len ) noexcept;
+  constexpr basic_string_view<wchar_t>  operator "" sv( const wchar_t *str,  size_t len ) noexcept;
+  constexpr basic_string_view<char8_t>  operator "" sv( const char8_t *str,  size_t len ) noexcept; // C++20
+  constexpr basic_string_view<char16_t> operator "" sv( const char16_t *str, size_t len ) noexcept;
+  constexpr basic_string_view<char32_t> operator "" sv( const char32_t *str, size_t len ) noexcept;
+
+}  // namespace std
+
+
+*/
+
+#include <__concepts/convertible_to.h>
+#include <__concepts/same_as.h>
+#include <__config>
+#include <__debug>
+#include <__ranges/enable_borrowed_range.h>
+#include <__ranges/enable_view.h>
+#include <__string>
+#include <algorithm>
+#include <compare>
+#include <iosfwd>
+#include <iterator>
+#include <limits>
+#include <stdexcept>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4455 )
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_string_view;
+
+typedef basic_string_view<char>     string_view;
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+typedef basic_string_view<char8_t>  u8string_view;
+#endif
+typedef basic_string_view<char16_t> u16string_view;
+typedef basic_string_view<char32_t> u32string_view;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef basic_string_view<wchar_t>  wstring_view;
+#endif
+
+template<class _CharT, class _Traits>
+class
+    _LIBCPP_PREFERRED_NAME(string_view)
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+    _LIBCPP_PREFERRED_NAME(u8string_view)
+#endif
+    _LIBCPP_PREFERRED_NAME(u16string_view)
+    _LIBCPP_PREFERRED_NAME(u32string_view)
+    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wstring_view))
+    basic_string_view {
+public:
+    // types
+    typedef _Traits                                    traits_type;
+    typedef _CharT                                     value_type;
+    typedef _CharT*                                    pointer;
+    typedef const _CharT*                              const_pointer;
+    typedef _CharT&                                    reference;
+    typedef const _CharT&                              const_reference;
+    typedef const_pointer                              const_iterator; // See [string.view.iterators]
+    typedef const_iterator                             iterator;
+    typedef _VSTD::reverse_iterator<const_iterator>    const_reverse_iterator;
+    typedef const_reverse_iterator                     reverse_iterator;
+    typedef size_t                                     size_type;
+    typedef ptrdiff_t                                  difference_type;
+    static _LIBCPP_CONSTEXPR const size_type npos = -1; // size_type(-1);
+
+    static_assert((!is_array<value_type>::value), "Character type of basic_string_view must not be an array");
+    static_assert(( is_standard_layout<value_type>::value), "Character type of basic_string_view must be standard-layout");
+    static_assert(( is_trivial<value_type>::value), "Character type of basic_string_view must be trivial");
+    static_assert((is_same<_CharT, typename traits_type::char_type>::value),
+                  "traits_type::char_type must be the same type as CharT");
+
+    // [string.view.cons], construct/copy
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    basic_string_view() _NOEXCEPT : __data (nullptr), __size(0) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string_view(const basic_string_view&) _NOEXCEPT = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string_view& operator=(const basic_string_view&) _NOEXCEPT = default;
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    basic_string_view(nullptr_t, size_t) = delete;
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    basic_string_view(const _CharT* __s, size_type __len) _NOEXCEPT
+        : __data(__s), __size(__len)
+    {
+#if _LIBCPP_STD_VER > 11
+    _LIBCPP_ASSERT(__len == 0 || __s != nullptr, "string_view::string_view(_CharT *, size_t): received nullptr");
+#endif
+    }
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+    template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
+      requires (same_as<iter_value_t<_It>, _CharT> && !convertible_to<_End, size_type>)
+    constexpr _LIBCPP_HIDE_FROM_ABI basic_string_view(_It __begin, _End __end)
+       : __data(_VSTD::to_address(__begin)), __size(__end - __begin)
+    {
+      _LIBCPP_ASSERT((__end - __begin) >= 0, "std::string_view::string_view(iterator, sentinel) received invalid range");
+    }
+#endif
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    basic_string_view(nullptr_t) = delete;
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    basic_string_view(const _CharT* __s)
+        : __data(__s), __size(_VSTD::__char_traits_length_checked<_Traits>(__s)) {}
+
+#if _LIBCPP_STD_VER > 20
+    basic_string_view(nullptr_t) = delete;
+#endif
+
+    // [string.view.iterators], iterators
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin()  const _NOEXCEPT { return cbegin(); }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()    const _NOEXCEPT { return cend(); }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin() const _NOEXCEPT { return __data; }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend()   const _NOEXCEPT { return __data + __size; }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rbegin()   const _NOEXCEPT { return const_reverse_iterator(cend()); }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rend()     const _NOEXCEPT { return const_reverse_iterator(cbegin()); }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crbegin()  const _NOEXCEPT { return const_reverse_iterator(cend()); }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crend()    const _NOEXCEPT { return const_reverse_iterator(cbegin()); }
+
+    // [string.view.capacity], capacity
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    size_type size()     const _NOEXCEPT { return __size; }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    size_type length()   const _NOEXCEPT { return __size; }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT { return numeric_limits<size_type>::max(); }
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    bool empty()         const _NOEXCEPT { return __size == 0; }
+
+    // [string.view.access], element access
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_reference operator[](size_type __pos) const _NOEXCEPT {
+      return _LIBCPP_ASSERT(__pos < size(), "string_view[] index out of bounds"), __data[__pos];
+    }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_reference at(size_type __pos) const
+    {
+        return __pos >= size()
+            ? (__throw_out_of_range("string_view::at"), __data[0])
+            : __data[__pos];
+    }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_reference front() const _NOEXCEPT
+    {
+        return _LIBCPP_ASSERT(!empty(), "string_view::front(): string is empty"), __data[0];
+    }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_reference back() const _NOEXCEPT
+    {
+        return _LIBCPP_ASSERT(!empty(), "string_view::back(): string is empty"), __data[__size-1];
+    }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_pointer data() const _NOEXCEPT { return __data; }
+
+    // [string.view.modifiers], modifiers:
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    void remove_prefix(size_type __n) _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n <= size(), "remove_prefix() can't remove more than size()");
+        __data += __n;
+        __size -= __n;
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    void remove_suffix(size_type __n) _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n <= size(), "remove_suffix() can't remove more than size()");
+        __size -= __n;
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    void swap(basic_string_view& __other) _NOEXCEPT
+    {
+        const value_type *__p = __data;
+        __data = __other.__data;
+        __other.__data = __p;
+
+        size_type __sz = __size;
+        __size = __other.__size;
+        __other.__size = __sz;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    size_type copy(_CharT* __s, size_type __n, size_type __pos = 0) const
+    {
+        if (__pos > size())
+            __throw_out_of_range("string_view::copy");
+        size_type __rlen = _VSTD::min(__n, size() - __pos);
+        _Traits::copy(__s, data() + __pos, __rlen);
+        return __rlen;
+    }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    basic_string_view substr(size_type __pos = 0, size_type __n = npos) const
+    {
+        return __pos > size()
+            ? (__throw_out_of_range("string_view::substr"), basic_string_view())
+            : basic_string_view(data() + __pos, _VSTD::min(__n, size() - __pos));
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 int compare(basic_string_view __sv) const _NOEXCEPT
+    {
+        size_type __rlen = _VSTD::min( size(), __sv.size());
+        int __retval = _Traits::compare(data(), __sv.data(), __rlen);
+        if ( __retval == 0 ) // first __rlen chars matched
+            __retval = size() == __sv.size() ? 0 : ( size() < __sv.size() ? -1 : 1 );
+        return __retval;
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    int compare(size_type __pos1, size_type __n1, basic_string_view __sv) const
+    {
+        return substr(__pos1, __n1).compare(__sv);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    int compare(                       size_type __pos1, size_type __n1,
+                basic_string_view __sv, size_type __pos2, size_type __n2) const
+    {
+        return substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    int compare(const _CharT* __s) const _NOEXCEPT
+    {
+        return compare(basic_string_view(__s));
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    int compare(size_type __pos1, size_type __n1, const _CharT* __s) const
+    {
+        return substr(__pos1, __n1).compare(basic_string_view(__s));
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    int compare(size_type __pos1, size_type __n1, const _CharT* __s, size_type __n2) const
+    {
+        return substr(__pos1, __n1).compare(basic_string_view(__s, __n2));
+    }
+
+    // find
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
+        return __str_find<value_type, size_type, traits_type, npos>
+            (data(), size(), __s.data(), __pos, __s.size());
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find(_CharT __c, size_type __pos = 0) const _NOEXCEPT
+    {
+        return __str_find<value_type, size_type, traits_type, npos>
+            (data(), size(), __c, __pos);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find(): received nullptr");
+        return __str_find<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, __n);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s != nullptr, "string_view::find(): received nullptr");
+        return __str_find<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, traits_type::length(__s));
+    }
+
+    // rfind
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type rfind(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
+        return __str_rfind<value_type, size_type, traits_type, npos>
+            (data(), size(), __s.data(), __pos, __s.size());
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type rfind(_CharT __c, size_type __pos = npos) const _NOEXCEPT
+    {
+        return __str_rfind<value_type, size_type, traits_type, npos>
+            (data(), size(), __c, __pos);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type rfind(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::rfind(): received nullptr");
+        return __str_rfind<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, __n);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type rfind(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s != nullptr, "string_view::rfind(): received nullptr");
+        return __str_rfind<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, traits_type::length(__s));
+    }
+
+    // find_first_of
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_of(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_first_of(): received nullptr");
+        return __str_find_first_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s.data(), __pos, __s.size());
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_of(_CharT __c, size_type __pos = 0) const _NOEXCEPT
+    { return find(__c, __pos); }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_first_of(): received nullptr");
+        return __str_find_first_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, __n);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_of(const _CharT* __s, size_type __pos=0) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_first_of(): received nullptr");
+        return __str_find_first_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, traits_type::length(__s));
+    }
+
+    // find_last_of
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_of(basic_string_view __s, size_type __pos=npos) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_last_of(): received nullptr");
+        return __str_find_last_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s.data(), __pos, __s.size());
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_of(_CharT __c, size_type __pos = npos) const _NOEXCEPT
+    { return rfind(__c, __pos); }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_last_of(): received nullptr");
+        return __str_find_last_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, __n);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_of(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_last_of(): received nullptr");
+        return __str_find_last_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, traits_type::length(__s));
+    }
+
+    // find_first_not_of
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_not_of(basic_string_view __s, size_type __pos=0) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_first_not_of(): received nullptr");
+        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s.data(), __pos, __s.size());
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_not_of(_CharT __c, size_type __pos=0) const _NOEXCEPT
+    {
+        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __c, __pos);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_first_not_of(): received nullptr");
+        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, __n);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_not_of(const _CharT* __s, size_type __pos=0) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_first_not_of(): received nullptr");
+        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, traits_type::length(__s));
+    }
+
+    // find_last_not_of
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_not_of(basic_string_view __s, size_type __pos=npos) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_last_not_of(): received nullptr");
+        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s.data(), __pos, __s.size());
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_not_of(_CharT __c, size_type __pos=npos) const _NOEXCEPT
+    {
+        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __c, __pos);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_last_not_of(): received nullptr");
+        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, __n);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_not_of(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_last_not_of(): received nullptr");
+        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, traits_type::length(__s));
+    }
+
+//WARN: disabled std guards in order to allow using these options without switching to new std
+//#if _LIBCPP_STD_VER > 17
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool starts_with(basic_string_view __s) const noexcept
+    { return size() >= __s.size() && compare(0, __s.size(), __s) == 0; }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool starts_with(value_type __c) const noexcept
+    { return !empty() && _Traits::eq(front(), __c); }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool starts_with(const value_type* __s) const noexcept
+    { return starts_with(basic_string_view(__s)); }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool ends_with(basic_string_view __s) const noexcept
+    { return size() >= __s.size() && compare(size() - __s.size(), npos, __s) == 0; }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool ends_with(value_type __c) const noexcept
+    { return !empty() && _Traits::eq(back(), __c); }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool ends_with(const value_type* __s) const noexcept
+    { return ends_with(basic_string_view(__s)); }
+//#endif
+
+#if _LIBCPP_STD_VER > 20
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool contains(basic_string_view __sv) const noexcept
+    { return find(__sv) != npos; }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool contains(value_type __c) const noexcept
+    { return find(__c) != npos; }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool contains(const value_type* __s) const
+    { return find(__s) != npos; }
+#endif
+
+private:
+    const   value_type* __data;
+    size_type           __size;
+};
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+template <class _CharT, class _Traits>
+inline constexpr bool ranges::enable_view<basic_string_view<_CharT, _Traits>> = true;
+
+template <class _CharT, class _Traits>
+inline constexpr bool ranges::enable_borrowed_range<basic_string_view<_CharT, _Traits> > = true;
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+
+// [string.view.deduct]
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
+  basic_string_view(_It, _End) -> basic_string_view<iter_value_t<_It>>;
+#endif
+
+// [string.view.comparison]
+// operator ==
+template<class _CharT, class _Traits>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator==(basic_string_view<_CharT, _Traits> __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    if ( __lhs.size() != __rhs.size()) return false;
+    return __lhs.compare(__rhs) == 0;
+}
+
+// Workaround for the bug in MSVC and clang on windows. Looks like MSVC generates the same
+// mangled name for this function as for the previous function. So we introduce
+// artificial difference to avoid that.
+#if defined(_LIBCPP_COMPILER_MSVC) || (defined(_WIN32) && defined(_LIBCPP_COMPILER_CLANG))
+template<class _CharT, class _Traits, int = 1>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator==(basic_string_view<_CharT, _Traits> __lhs,
+                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
+{
+    if ( __lhs.size() != __rhs.size()) return false;
+    return __lhs.compare(__rhs) == 0;
+}
+
+#if defined(_LIBCPP_COMPILER_MSVC) || (defined(_WIN32) && defined(_LIBCPP_COMPILER_CLANG))
+template<class _CharT, class _Traits, int = 2>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator==(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    if ( __lhs.size() != __rhs.size()) return false;
+    return __lhs.compare(__rhs) == 0;
+}
+
+
+// operator !=
+template<class _CharT, class _Traits>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator!=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    if ( __lhs.size() != __rhs.size())
+        return true;
+    return __lhs.compare(__rhs) != 0;
+}
+
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 1>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator!=(basic_string_view<_CharT, _Traits> __lhs,
+                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
+{
+    if ( __lhs.size() != __rhs.size())
+        return true;
+    return __lhs.compare(__rhs) != 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 2>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator!=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    if ( __lhs.size() != __rhs.size())
+        return true;
+    return __lhs.compare(__rhs) != 0;
+}
+
+
+// operator <
+template<class _CharT, class _Traits>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator<(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) < 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 1>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator<(basic_string_view<_CharT, _Traits> __lhs,
+                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) < 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 2>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator<(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) < 0;
+}
+
+
+// operator >
+template<class _CharT, class _Traits>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator> (basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) > 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 1>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator>(basic_string_view<_CharT, _Traits> __lhs,
+                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) > 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 2>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator>(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) > 0;
+}
+
+
+// operator <=
+template<class _CharT, class _Traits>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator<=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) <= 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 1>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator<=(basic_string_view<_CharT, _Traits> __lhs,
+                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) <= 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 2>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator<=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) <= 0;
+}
+
+
+// operator >=
+template<class _CharT, class _Traits>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator>=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) >= 0;
+}
+
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 1>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator>=(basic_string_view<_CharT, _Traits> __lhs,
+                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) >= 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 2>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator>=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) >= 0;
+}
+
+
+template<class _CharT, class _Traits>
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           basic_string_view<_CharT, _Traits> __str);
+
+// [string.view.hash]
+template<class _CharT>
+struct _LIBCPP_TEMPLATE_VIS hash<basic_string_view<_CharT, char_traits<_CharT> > >
+    : public unary_function<basic_string_view<_CharT, char_traits<_CharT> >, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const basic_string_view<_CharT, char_traits<_CharT> > __val) const _NOEXCEPT {
+        return __do_string_hash(__val.data(), __val.data() + __val.size());
+    }
+};
+
+
+#if _LIBCPP_STD_VER > 11
+inline namespace literals
+{
+  inline namespace string_view_literals
+  {
+    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    basic_string_view<char> operator "" sv(const char *__str, size_t __len) _NOEXCEPT
+    {
+        return basic_string_view<char> (__str, __len);
+    }
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    basic_string_view<wchar_t> operator "" sv(const wchar_t *__str, size_t __len) _NOEXCEPT
+    {
+        return basic_string_view<wchar_t> (__str, __len);
+    }
+#endif
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    basic_string_view<char8_t> operator "" sv(const char8_t *__str, size_t __len) _NOEXCEPT
+    {
+        return basic_string_view<char8_t> (__str, __len);
+    }
+#endif
+
+    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    basic_string_view<char16_t> operator "" sv(const char16_t *__str, size_t __len) _NOEXCEPT
+    {
+        return basic_string_view<char16_t> (__str, __len);
+    }
+
+    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    basic_string_view<char32_t> operator "" sv(const char32_t *__str, size_t __len) _NOEXCEPT
+    {
+        return basic_string_view<char32_t> (__str, __len);
+    }
+  }
+}
+#endif
+_LIBCPP_END_NAMESPACE_STD
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_STRING_VIEW
diff --git a/contrib/libs/cxxsupp/libcxx/include/strstream b/contrib/libs/cxxsupp/libcxx/include/strstream
new file mode 100644
index 00000000000..ca837aef670
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/strstream
@@ -0,0 +1,407 @@
+// -*- C++ -*-
+//===--------------------------- strstream --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_STRSTREAM
+#define _LIBCPP_STRSTREAM
+
+/*
+    strstream synopsis
+
+class strstreambuf
+    : public basic_streambuf<char>
+{
+public:
+    explicit strstreambuf(streamsize alsize_arg = 0); // before C++20
+    strstreambuf() : strstreambuf(0) {}               // C++20
+    explicit strstreambuf(streamsize alsize_arg);     // C++20
+
+    strstreambuf(void* (*palloc_arg)(size_t), void (*pfree_arg)(void*));
+    strstreambuf(char* gnext_arg, streamsize n, char* pbeg_arg = nullptr);
+    strstreambuf(const char* gnext_arg, streamsize n);
+
+    strstreambuf(signed char* gnext_arg, streamsize n, signed char* pbeg_arg = nullptr);
+    strstreambuf(const signed char* gnext_arg, streamsize n);
+    strstreambuf(unsigned char* gnext_arg, streamsize n, unsigned char* pbeg_arg = nullptr);
+    strstreambuf(const unsigned char* gnext_arg, streamsize n);
+
+    strstreambuf(strstreambuf&& rhs);
+    strstreambuf& operator=(strstreambuf&& rhs);
+
+    virtual ~strstreambuf();
+
+    void swap(strstreambuf& rhs);
+
+    void freeze(bool freezefl = true);
+    char* str();
+    int pcount() const;
+
+protected:
+    virtual int_type overflow (int_type c = EOF);
+    virtual int_type pbackfail(int_type c = EOF);
+    virtual int_type underflow();
+    virtual pos_type seekoff(off_type off, ios_base::seekdir way,
+                             ios_base::openmode which = ios_base::in | ios_base::out);
+    virtual pos_type seekpos(pos_type sp,
+                             ios_base::openmode which = ios_base::in | ios_base::out);
+    virtual streambuf* setbuf(char* s, streamsize n);
+
+private:
+    typedef T1 strstate;                // exposition only
+    static const strstate allocated;    // exposition only
+    static const strstate constant;     // exposition only
+    static const strstate dynamic;      // exposition only
+    static const strstate frozen;       // exposition only
+    strstate strmode;                   // exposition only
+    streamsize alsize;                  // exposition only
+    void* (*palloc)(size_t);            // exposition only
+    void (*pfree)(void*);               // exposition only
+};
+
+class istrstream
+    : public basic_istream<char>
+{
+public:
+    explicit istrstream(const char* s);
+    explicit istrstream(char* s);
+    istrstream(const char* s, streamsize n);
+    istrstream(char* s, streamsize n);
+
+    virtual ~istrstream();
+
+    strstreambuf* rdbuf() const;
+    char *str();
+
+private:
+    strstreambuf sb; // exposition only
+};
+
+class ostrstream
+    : public basic_ostream<char>
+{
+public:
+    ostrstream();
+    ostrstream(char* s, int n, ios_base::openmode mode = ios_base::out);
+
+    virtual ~ostrstream();
+
+    strstreambuf* rdbuf() const;
+    void freeze(bool freezefl = true);
+    char* str();
+    int pcount() const;
+
+private:
+    strstreambuf sb; // exposition only
+};
+
+class strstream
+    : public basic_iostream<char>
+{
+public:
+    // Types
+    typedef char                        char_type;
+    typedef char_traits<char>::int_type int_type;
+    typedef char_traits<char>::pos_type pos_type;
+    typedef char_traits<char>::off_type off_type;
+
+    // constructors/destructor
+    strstream();
+    strstream(char* s, int n, ios_base::openmode mode = ios_base::in | ios_base::out);
+
+    virtual ~strstream();
+
+    // Members:
+    strstreambuf* rdbuf() const;
+    void freeze(bool freezefl = true);
+    int pcount() const;
+    char* str();
+
+private:
+    strstreambuf sb; // exposition only
+};
+
+}  // std
+
+*/
+
+#include <__config>
+#include <istream>
+#include <ostream>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+class _LIBCPP_TYPE_VIS strstreambuf
+    : public streambuf
+{
+public:
+#ifndef _LIBCPP_CXX03_LANG
+    strstreambuf() : strstreambuf(0) {}
+    explicit strstreambuf(streamsize __alsize);
+#else
+    explicit strstreambuf(streamsize __alsize = 0);
+#endif
+    strstreambuf(void* (*__palloc)(size_t), void (*__pfree)(void*));
+    strstreambuf(char* __gnext, streamsize __n, char* __pbeg = nullptr);
+    strstreambuf(const char* __gnext, streamsize __n);
+
+    strstreambuf(signed char* __gnext, streamsize __n, signed char* __pbeg = nullptr);
+    strstreambuf(const signed char* __gnext, streamsize __n);
+    strstreambuf(unsigned char* __gnext, streamsize __n, unsigned char* __pbeg = nullptr);
+    strstreambuf(const unsigned char* __gnext, streamsize __n);
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    strstreambuf(strstreambuf&& __rhs);
+    _LIBCPP_INLINE_VISIBILITY
+    strstreambuf& operator=(strstreambuf&& __rhs);
+#endif // _LIBCPP_CXX03_LANG
+
+    virtual ~strstreambuf();
+
+    void swap(strstreambuf& __rhs);
+
+    void freeze(bool __freezefl = true);
+    char* str();
+    int pcount() const;
+
+protected:
+    virtual int_type overflow (int_type __c = EOF);
+    virtual int_type pbackfail(int_type __c = EOF);
+    virtual int_type underflow();
+    virtual pos_type seekoff(off_type __off, ios_base::seekdir __way,
+                             ios_base::openmode __which = ios_base::in | ios_base::out);
+    virtual pos_type seekpos(pos_type __sp,
+                             ios_base::openmode __which = ios_base::in | ios_base::out);
+
+private:
+    typedef unsigned __mode_type;
+    static const __mode_type __allocated = 0x01;
+    static const __mode_type __constant  = 0x02;
+    static const __mode_type __dynamic   = 0x04;
+    static const __mode_type __frozen    = 0x08;
+    static const streamsize    __default_alsize = 4096;
+
+    __mode_type __strmode_;
+    streamsize __alsize_;
+    void* (*__palloc_)(size_t);
+    void (*__pfree_)(void*);
+
+    void __init(char* __gnext, streamsize __n, char* __pbeg);
+};
+
+#ifndef _LIBCPP_CXX03_LANG
+
+inline _LIBCPP_INLINE_VISIBILITY
+strstreambuf::strstreambuf(strstreambuf&& __rhs)
+    : streambuf(__rhs),
+      __strmode_(__rhs.__strmode_),
+      __alsize_(__rhs.__alsize_),
+      __palloc_(__rhs.__palloc_),
+      __pfree_(__rhs.__pfree_)
+{
+    __rhs.setg(nullptr, nullptr, nullptr);
+    __rhs.setp(nullptr, nullptr);
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+strstreambuf&
+strstreambuf::operator=(strstreambuf&& __rhs)
+{
+    if (eback() && (__strmode_ & __allocated) != 0 && (__strmode_ & __frozen) == 0)
+    {
+        if (__pfree_)
+            __pfree_(eback());
+        else
+            delete [] eback();
+    }
+    streambuf::operator=(__rhs);
+    __strmode_ = __rhs.__strmode_;
+    __alsize_ = __rhs.__alsize_;
+    __palloc_ = __rhs.__palloc_;
+    __pfree_ = __rhs.__pfree_;
+    __rhs.setg(nullptr, nullptr, nullptr);
+    __rhs.setp(nullptr, nullptr);
+    return *this;
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+class _LIBCPP_TYPE_VIS istrstream
+    : public istream
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit istrstream(const char* __s)
+        : istream(&__sb_), __sb_(__s, 0) {}
+    _LIBCPP_INLINE_VISIBILITY
+    explicit istrstream(char* __s)
+        : istream(&__sb_), __sb_(__s, 0) {}
+    _LIBCPP_INLINE_VISIBILITY
+    istrstream(const char* __s, streamsize __n)
+        : istream(&__sb_), __sb_(__s, __n) {}
+    _LIBCPP_INLINE_VISIBILITY
+    istrstream(char* __s, streamsize __n)
+        : istream(&__sb_), __sb_(__s, __n) {}
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    istrstream(istrstream&& __rhs)
+        : istream(_VSTD::move(__rhs)),
+          __sb_(_VSTD::move(__rhs.__sb_))
+    {
+        istream::set_rdbuf(&__sb_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    istrstream& operator=(istrstream&& __rhs)
+    {
+        istream::operator=(_VSTD::move(__rhs));
+        __sb_ = _VSTD::move(__rhs.__sb_);
+        return *this;
+    }
+#endif // _LIBCPP_CXX03_LANG
+
+    virtual ~istrstream();
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(istrstream& __rhs)
+    {
+        istream::swap(__rhs);
+        __sb_.swap(__rhs.__sb_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    strstreambuf* rdbuf() const {return const_cast<strstreambuf*>(&__sb_);}
+    _LIBCPP_INLINE_VISIBILITY
+    char *str() {return __sb_.str();}
+
+private:
+    strstreambuf __sb_;
+};
+
+class _LIBCPP_TYPE_VIS ostrstream
+    : public ostream
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    ostrstream()
+        : ostream(&__sb_) {}
+    _LIBCPP_INLINE_VISIBILITY
+    ostrstream(char* __s, int __n, ios_base::openmode __mode = ios_base::out)
+        : ostream(&__sb_),
+          __sb_(__s, __n, __s + (__mode & ios::app ? _VSTD::strlen(__s) : 0))
+        {}
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    ostrstream(ostrstream&& __rhs)
+        : ostream(_VSTD::move(__rhs)),
+          __sb_(_VSTD::move(__rhs.__sb_))
+    {
+        ostream::set_rdbuf(&__sb_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    ostrstream& operator=(ostrstream&& __rhs)
+    {
+        ostream::operator=(_VSTD::move(__rhs));
+        __sb_ = _VSTD::move(__rhs.__sb_);
+        return *this;
+    }
+#endif // _LIBCPP_CXX03_LANG
+
+    virtual ~ostrstream();
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(ostrstream& __rhs)
+    {
+        ostream::swap(__rhs);
+        __sb_.swap(__rhs.__sb_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    strstreambuf* rdbuf() const {return const_cast<strstreambuf*>(&__sb_);}
+    _LIBCPP_INLINE_VISIBILITY
+    void freeze(bool __freezefl = true) {__sb_.freeze(__freezefl);}
+    _LIBCPP_INLINE_VISIBILITY
+    char* str()         {return __sb_.str();}
+    _LIBCPP_INLINE_VISIBILITY
+    int pcount() const  {return __sb_.pcount();}
+
+private:
+    strstreambuf __sb_; // exposition only
+};
+
+class _LIBCPP_TYPE_VIS strstream
+    : public iostream
+{
+public:
+    // Types
+    typedef char                        char_type;
+    typedef char_traits<char>::int_type int_type;
+    typedef char_traits<char>::pos_type pos_type;
+    typedef char_traits<char>::off_type off_type;
+
+    // constructors/destructor
+    _LIBCPP_INLINE_VISIBILITY
+    strstream()
+        : iostream(&__sb_) {}
+    _LIBCPP_INLINE_VISIBILITY
+    strstream(char* __s, int __n, ios_base::openmode __mode = ios_base::in | ios_base::out)
+        : iostream(&__sb_),
+          __sb_(__s, __n, __s + (__mode & ios::app ? _VSTD::strlen(__s) : 0))
+        {}
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    strstream(strstream&& __rhs)
+        : iostream(_VSTD::move(__rhs)),
+          __sb_(_VSTD::move(__rhs.__sb_))
+    {
+        iostream::set_rdbuf(&__sb_);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    strstream& operator=(strstream&& __rhs)
+    {
+        iostream::operator=(_VSTD::move(__rhs));
+        __sb_ = _VSTD::move(__rhs.__sb_);
+        return *this;
+    }
+#endif // _LIBCPP_CXX03_LANG
+
+    virtual ~strstream();
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(strstream& __rhs)
+    {
+        iostream::swap(__rhs);
+        __sb_.swap(__rhs.__sb_);
+    }
+
+    // Members:
+    _LIBCPP_INLINE_VISIBILITY
+    strstreambuf* rdbuf() const {return const_cast<strstreambuf*>(&__sb_);}
+    _LIBCPP_INLINE_VISIBILITY
+    void freeze(bool __freezefl = true) {__sb_.freeze(__freezefl);}
+    _LIBCPP_INLINE_VISIBILITY
+    int pcount() const {return __sb_.pcount();}
+    _LIBCPP_INLINE_VISIBILITY
+    char* str()        {return __sb_.str();}
+
+private:
+    strstreambuf __sb_; // exposition only
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STRSTREAM
diff --git a/contrib/libs/cxxsupp/libcxx/include/system_error b/contrib/libs/cxxsupp/libcxx/include/system_error
new file mode 100644
index 00000000000..7e6d3c1cc54
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/system_error
@@ -0,0 +1,490 @@
+// -*- C++ -*-
+//===---------------------------- system_error ----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SYSTEM_ERROR
+#define _LIBCPP_SYSTEM_ERROR
+
+/*
+    system_error synopsis
+
+namespace std
+{
+
+class error_category
+{
+public:
+    virtual ~error_category() noexcept;
+
+    constexpr error_category();
+    error_category(const error_category&) = delete;
+    error_category& operator=(const error_category&) = delete;
+
+    virtual const char* name() const noexcept = 0;
+    virtual error_condition default_error_condition(int ev) const noexcept;
+    virtual bool equivalent(int code, const error_condition& condition) const noexcept;
+    virtual bool equivalent(const error_code& code, int condition) const noexcept;
+    virtual string message(int ev) const = 0;
+
+    bool operator==(const error_category& rhs) const noexcept;
+    bool operator!=(const error_category& rhs) const noexcept;
+    bool operator<(const error_category& rhs) const noexcept;
+};
+
+const error_category& generic_category() noexcept;
+const error_category& system_category() noexcept;
+
+template <class T> struct is_error_code_enum
+    : public false_type {};
+
+template <class T> struct is_error_condition_enum
+    : public false_type {};
+
+template <class _Tp>
+inline constexpr size_t is_error_condition_enum_v = is_error_condition_enum<_Tp>::value; // C++17
+
+template <class _Tp>
+inline constexpr size_t is_error_code_enum_v = is_error_code_enum<_Tp>::value; // C++17
+
+class error_code
+{
+public:
+    // constructors:
+    error_code() noexcept;
+    error_code(int val, const error_category& cat) noexcept;
+    template <class ErrorCodeEnum>
+        error_code(ErrorCodeEnum e) noexcept;
+
+    // modifiers:
+    void assign(int val, const error_category& cat) noexcept;
+    template <class ErrorCodeEnum>
+        error_code& operator=(ErrorCodeEnum e) noexcept;
+    void clear() noexcept;
+
+    // observers:
+    int value() const noexcept;
+    const error_category& category() const noexcept;
+    error_condition default_error_condition() const noexcept;
+    string message() const;
+    explicit operator bool() const noexcept;
+};
+
+// non-member functions:
+bool operator<(const error_code& lhs, const error_code& rhs) noexcept;
+template <class charT, class traits>
+    basic_ostream<charT,traits>&
+    operator<<(basic_ostream<charT,traits>& os, const error_code& ec);
+
+class error_condition
+{
+public:
+    // constructors:
+    error_condition() noexcept;
+    error_condition(int val, const error_category& cat) noexcept;
+    template <class ErrorConditionEnum>
+        error_condition(ErrorConditionEnum e) noexcept;
+
+    // modifiers:
+    void assign(int val, const error_category& cat) noexcept;
+    template <class ErrorConditionEnum>
+        error_condition& operator=(ErrorConditionEnum e) noexcept;
+    void clear() noexcept;
+
+    // observers:
+    int value() const noexcept;
+    const error_category& category() const noexcept;
+    string message() const noexcept;
+    explicit operator bool() const noexcept;
+};
+
+bool operator<(const error_condition& lhs, const error_condition& rhs) noexcept;
+
+class system_error
+    : public runtime_error
+{
+public:
+    system_error(error_code ec, const string& what_arg);
+    system_error(error_code ec, const char* what_arg);
+    system_error(error_code ec);
+    system_error(int ev, const error_category& ecat, const string& what_arg);
+    system_error(int ev, const error_category& ecat, const char* what_arg);
+    system_error(int ev, const error_category& ecat);
+
+    const error_code& code() const noexcept;
+    const char* what() const noexcept;
+};
+
+template <> struct is_error_condition_enum<errc>
+    : true_type { }
+
+error_code make_error_code(errc e) noexcept;
+error_condition make_error_condition(errc e) noexcept;
+
+// Comparison operators:
+bool operator==(const error_code& lhs, const error_code& rhs) noexcept;
+bool operator==(const error_code& lhs, const error_condition& rhs) noexcept;
+bool operator==(const error_condition& lhs, const error_code& rhs) noexcept;
+bool operator==(const error_condition& lhs, const error_condition& rhs) noexcept;
+bool operator!=(const error_code& lhs, const error_code& rhs) noexcept;
+bool operator!=(const error_code& lhs, const error_condition& rhs) noexcept;
+bool operator!=(const error_condition& lhs, const error_code& rhs) noexcept;
+bool operator!=(const error_condition& lhs, const error_condition& rhs) noexcept;
+
+template <> struct hash<std::error_code>;
+template <> struct hash<std::error_condition>;
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__errc>
+#include <__functional/unary_function.h>
+#include <__functional_base>
+#include <compare>
+#include <stdexcept>
+#include <string>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// is_error_code_enum
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_error_code_enum
+    : public false_type {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr size_t is_error_code_enum_v = is_error_code_enum<_Tp>::value;
+#endif
+
+// is_error_condition_enum
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_error_condition_enum
+    : public false_type {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr size_t is_error_condition_enum_v = is_error_condition_enum<_Tp>::value;
+#endif
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS is_error_condition_enum<errc>
+    : true_type { };
+
+#ifdef _LIBCPP_HAS_NO_STRONG_ENUMS
+template <>
+struct _LIBCPP_TEMPLATE_VIS is_error_condition_enum<errc::__lx>
+    : true_type { };
+#endif
+
+class _LIBCPP_TYPE_VIS error_condition;
+class _LIBCPP_TYPE_VIS error_code;
+
+// class error_category
+
+class _LIBCPP_HIDDEN __do_message;
+
+class _LIBCPP_TYPE_VIS error_category
+{
+public:
+    virtual ~error_category() _NOEXCEPT;
+
+// ODR violation is used for binary compatibility with older versions of libc++.
+// We don't have old libc++ versions for MSVC, so we don't need it.
+#if defined(_LIBCPP_BUILDING_LIBRARY) && \
+    defined(_LIBCPP_DEPRECATED_ABI_LEGACY_LIBRARY_DEFINITIONS_FOR_INLINE_FUNCTIONS)
+    error_category() _NOEXCEPT;
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 error_category() _NOEXCEPT _LIBCPP_DEFAULT
+#endif
+private:
+    error_category(const error_category&);// = delete;
+    error_category& operator=(const error_category&);// = delete;
+
+public:
+    virtual const char* name() const _NOEXCEPT = 0;
+    virtual error_condition default_error_condition(int __ev) const _NOEXCEPT;
+    virtual bool equivalent(int __code, const error_condition& __condition) const _NOEXCEPT;
+    virtual bool equivalent(const error_code& __code, int __condition) const _NOEXCEPT;
+    virtual string message(int __ev) const = 0;
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const error_category& __rhs) const _NOEXCEPT {return this == &__rhs;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const error_category& __rhs) const _NOEXCEPT {return !(*this == __rhs);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator< (const error_category& __rhs) const _NOEXCEPT {return this < &__rhs;}
+
+    friend class _LIBCPP_HIDDEN __do_message;
+};
+
+class _LIBCPP_HIDDEN __do_message
+    : public error_category
+{
+public:
+    virtual string message(int ev) const;
+};
+
+_LIBCPP_FUNC_VIS const error_category& generic_category() _NOEXCEPT;
+_LIBCPP_FUNC_VIS const error_category& system_category() _NOEXCEPT;
+
+class _LIBCPP_TYPE_VIS error_condition
+{
+    int __val_;
+    const error_category* __cat_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    error_condition() _NOEXCEPT : __val_(0), __cat_(&generic_category()) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    error_condition(int __val, const error_category& __cat) _NOEXCEPT
+        : __val_(__val), __cat_(&__cat) {}
+
+    template <class _Ep>
+        _LIBCPP_INLINE_VISIBILITY
+        error_condition(_Ep __e,
+              typename enable_if<is_error_condition_enum<_Ep>::value>::type* = nullptr
+                                                                     ) _NOEXCEPT
+            {*this = make_error_condition(__e);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void assign(int __val, const error_category& __cat) _NOEXCEPT
+    {
+        __val_ = __val;
+        __cat_ = &__cat;
+    }
+
+    template <class _Ep>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            is_error_condition_enum<_Ep>::value,
+            error_condition&
+        >::type
+        operator=(_Ep __e) _NOEXCEPT
+            {*this = make_error_condition(__e); return *this;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT
+    {
+        __val_ = 0;
+        __cat_ = &generic_category();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int value() const _NOEXCEPT {return __val_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    const error_category& category() const _NOEXCEPT {return *__cat_;}
+    string message() const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit operator bool() const _NOEXCEPT {return __val_ != 0;}
+};
+
+inline _LIBCPP_INLINE_VISIBILITY
+error_condition
+make_error_condition(errc __e) _NOEXCEPT
+{
+    return error_condition(static_cast<int>(__e), generic_category());
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(const error_condition& __x, const error_condition& __y) _NOEXCEPT
+{
+    return __x.category() < __y.category()
+        || (__x.category() == __y.category() && __x.value() < __y.value());
+}
+
+// error_code
+
+class _LIBCPP_TYPE_VIS error_code
+{
+    int __val_;
+    const error_category* __cat_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    error_code() _NOEXCEPT : __val_(0), __cat_(&system_category()) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    error_code(int __val, const error_category& __cat) _NOEXCEPT
+        : __val_(__val), __cat_(&__cat) {}
+
+    template <class _Ep>
+        _LIBCPP_INLINE_VISIBILITY
+        error_code(_Ep __e,
+                   typename enable_if<is_error_code_enum<_Ep>::value>::type* = nullptr
+                                                                     ) _NOEXCEPT
+            {*this = make_error_code(__e);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void assign(int __val, const error_category& __cat) _NOEXCEPT
+    {
+        __val_ = __val;
+        __cat_ = &__cat;
+    }
+
+    template <class _Ep>
+        _LIBCPP_INLINE_VISIBILITY
+        typename enable_if
+        <
+            is_error_code_enum<_Ep>::value,
+            error_code&
+        >::type
+        operator=(_Ep __e) _NOEXCEPT
+            {*this = make_error_code(__e); return *this;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT
+    {
+        __val_ = 0;
+        __cat_ = &system_category();
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    int value() const _NOEXCEPT {return __val_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    const error_category& category() const _NOEXCEPT {return *__cat_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    error_condition default_error_condition() const _NOEXCEPT
+        {return __cat_->default_error_condition(__val_);}
+
+    string message() const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit operator bool() const _NOEXCEPT {return __val_ != 0;}
+};
+
+inline _LIBCPP_INLINE_VISIBILITY
+error_code
+make_error_code(errc __e) _NOEXCEPT
+{
+    return error_code(static_cast<int>(__e), generic_category());
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<(const error_code& __x, const error_code& __y) _NOEXCEPT
+{
+    return __x.category() < __y.category()
+        || (__x.category() == __y.category() && __x.value() < __y.value());
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const error_code& __x, const error_code& __y) _NOEXCEPT
+{
+    return __x.category() == __y.category() && __x.value() == __y.value();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const error_code& __x, const error_condition& __y) _NOEXCEPT
+{
+    return __x.category().equivalent(__x.value(), __y)
+        || __y.category().equivalent(__x, __y.value());
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const error_condition& __x, const error_code& __y) _NOEXCEPT
+{
+    return __y == __x;
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const error_condition& __x, const error_condition& __y) _NOEXCEPT
+{
+    return __x.category() == __y.category() && __x.value() == __y.value();
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const error_code& __x, const error_code& __y) _NOEXCEPT
+{return !(__x == __y);}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const error_code& __x, const error_condition& __y) _NOEXCEPT
+{return !(__x == __y);}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const error_condition& __x, const error_code& __y) _NOEXCEPT
+{return !(__x == __y);}
+
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const error_condition& __x, const error_condition& __y) _NOEXCEPT
+{return !(__x == __y);}
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<error_code>
+    : public unary_function<error_code, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const error_code& __ec) const _NOEXCEPT
+    {
+        return static_cast<size_t>(__ec.value());
+    }
+};
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<error_condition>
+    : public unary_function<error_condition, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const error_condition& __ec) const _NOEXCEPT
+    {
+        return static_cast<size_t>(__ec.value());
+    }
+};
+
+// system_error
+
+class _LIBCPP_TYPE_VIS system_error
+    : public runtime_error
+{
+    error_code __ec_;
+public:
+    system_error(error_code __ec, const string& __what_arg);
+    system_error(error_code __ec, const char* __what_arg);
+    system_error(error_code __ec);
+    system_error(int __ev, const error_category& __ecat, const string& __what_arg);
+    system_error(int __ev, const error_category& __ecat, const char* __what_arg);
+    system_error(int __ev, const error_category& __ecat);
+    system_error(const system_error&) _NOEXCEPT = default;
+    ~system_error() _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    const error_code& code() const _NOEXCEPT {return __ec_;}
+
+private:
+    static string __init(const error_code&, string);
+};
+
+_LIBCPP_NORETURN _LIBCPP_FUNC_VIS
+void __throw_system_error(int ev, const char* what_arg);
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_SYSTEM_ERROR
diff --git a/contrib/libs/cxxsupp/libcxx/include/tgmath.h b/contrib/libs/cxxsupp/libcxx/include/tgmath.h
new file mode 100644
index 00000000000..ba9396e6abb
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/tgmath.h
@@ -0,0 +1,36 @@
+// -*- C++ -*-
+//===-------------------------- tgmath.h ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_TGMATH_H
+#define _LIBCPP_TGMATH_H
+
+/*
+    tgmath.h synopsis
+
+#include <ctgmath>
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef __cplusplus
+
+#include <ctgmath>
+
+#else  // __cplusplus
+
+#include_next <tgmath.h>
+
+#endif // __cplusplus
+
+#endif // _LIBCPP_TGMATH_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/thread b/contrib/libs/cxxsupp/libcxx/include/thread
new file mode 100644
index 00000000000..9b591976acc
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/thread
@@ -0,0 +1,413 @@
+// -*- C++ -*-
+//===--------------------------- thread -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_THREAD
+#define _LIBCPP_THREAD
+
+/*
+
+    thread synopsis
+
+namespace std
+{
+
+class thread
+{
+public:
+    class id;
+    typedef pthread_t native_handle_type;
+
+    thread() noexcept;
+    template <class F, class ...Args> explicit thread(F&& f, Args&&... args);
+    ~thread();
+
+    thread(const thread&) = delete;
+    thread(thread&& t) noexcept;
+
+    thread& operator=(const thread&) = delete;
+    thread& operator=(thread&& t) noexcept;
+
+    void swap(thread& t) noexcept;
+
+    bool joinable() const noexcept;
+    void join();
+    void detach();
+    id get_id() const noexcept;
+    native_handle_type native_handle();
+
+    static unsigned hardware_concurrency() noexcept;
+};
+
+void swap(thread& x, thread& y) noexcept;
+
+class thread::id
+{
+public:
+    id() noexcept;
+};
+
+bool operator==(thread::id x, thread::id y) noexcept;
+bool operator!=(thread::id x, thread::id y) noexcept;
+bool operator< (thread::id x, thread::id y) noexcept;
+bool operator<=(thread::id x, thread::id y) noexcept;
+bool operator> (thread::id x, thread::id y) noexcept;
+bool operator>=(thread::id x, thread::id y) noexcept;
+
+template<class charT, class traits>
+basic_ostream<charT, traits>&
+operator<<(basic_ostream<charT, traits>& out, thread::id id);
+
+namespace this_thread
+{
+
+thread::id get_id() noexcept;
+
+void yield() noexcept;
+
+template <class Clock, class Duration>
+void sleep_until(const chrono::time_point<Clock, Duration>& abs_time);
+
+template <class Rep, class Period>
+void sleep_for(const chrono::duration<Rep, Period>& rel_time);
+
+}  // this_thread
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__functional_base>
+#include <__mutex_base>
+#include <__threading_support>
+#include <__utility/decay_copy.h>
+#include <__utility/forward.h>
+#include <chrono>
+#include <cstddef>
+#include <functional>
+#include <iosfwd>
+#include <memory>
+#include <system_error>
+#include <tuple>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#ifdef _LIBCPP_HAS_NO_THREADS
+#error <thread> is not supported on this single threaded system
+#else // !_LIBCPP_HAS_NO_THREADS
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp> class __thread_specific_ptr;
+class _LIBCPP_TYPE_VIS __thread_struct;
+class _LIBCPP_HIDDEN __thread_struct_imp;
+class __assoc_sub_state;
+
+_LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();
+
+class _LIBCPP_TYPE_VIS __thread_struct
+{
+    __thread_struct_imp* __p_;
+
+    __thread_struct(const __thread_struct&);
+    __thread_struct& operator=(const __thread_struct&);
+public:
+    __thread_struct();
+    ~__thread_struct();
+
+    void notify_all_at_thread_exit(condition_variable*, mutex*);
+    void __make_ready_at_thread_exit(__assoc_sub_state*);
+};
+
+template <class _Tp>
+class __thread_specific_ptr
+{
+    __libcpp_tls_key __key_;
+
+     // Only __thread_local_data() may construct a __thread_specific_ptr
+     // and only with _Tp == __thread_struct.
+    static_assert((is_same<_Tp, __thread_struct>::value), "");
+    __thread_specific_ptr();
+    friend _LIBCPP_FUNC_VIS __thread_specific_ptr<__thread_struct>& __thread_local_data();
+
+    __thread_specific_ptr(const __thread_specific_ptr&);
+    __thread_specific_ptr& operator=(const __thread_specific_ptr&);
+
+    _LIBCPP_HIDDEN static void _LIBCPP_TLS_DESTRUCTOR_CC __at_thread_exit(void*);
+
+public:
+    typedef _Tp* pointer;
+
+    ~__thread_specific_ptr();
+
+    _LIBCPP_INLINE_VISIBILITY
+    pointer get() const {return static_cast<_Tp*>(__libcpp_tls_get(__key_));}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator*() const {return *get();}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {return get();}
+    void set_pointer(pointer __p);
+};
+
+template <class _Tp>
+void _LIBCPP_TLS_DESTRUCTOR_CC
+__thread_specific_ptr<_Tp>::__at_thread_exit(void* __p)
+{
+    delete static_cast<pointer>(__p);
+}
+
+template <class _Tp>
+__thread_specific_ptr<_Tp>::__thread_specific_ptr()
+{
+  int __ec =
+      __libcpp_tls_create(&__key_, &__thread_specific_ptr::__at_thread_exit);
+  if (__ec)
+    __throw_system_error(__ec, "__thread_specific_ptr construction failed");
+}
+
+template <class _Tp>
+__thread_specific_ptr<_Tp>::~__thread_specific_ptr()
+{
+    // __thread_specific_ptr is only created with a static storage duration
+    // so this destructor is only invoked during program termination. Invoking
+    // pthread_key_delete(__key_) may prevent other threads from deleting their
+    // thread local data. For this reason we leak the key.
+}
+
+template <class _Tp>
+void
+__thread_specific_ptr<_Tp>::set_pointer(pointer __p)
+{
+    _LIBCPP_ASSERT(get() == nullptr,
+                   "Attempting to overwrite thread local data");
+    __libcpp_tls_set(__key_, __p);
+}
+
+template<>
+struct _LIBCPP_TEMPLATE_VIS hash<__thread_id>
+    : public unary_function<__thread_id, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(__thread_id __v) const _NOEXCEPT
+    {
+        return hash<__libcpp_thread_id>()(__v.__id_);
+    }
+};
+
+template<class _CharT, class _Traits>
+_LIBCPP_INLINE_VISIBILITY
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, __thread_id __id)
+{return __os << __id.__id_;}
+
+class _LIBCPP_TYPE_VIS thread
+{
+    __libcpp_thread_t __t_;
+
+    thread(const thread&);
+    thread& operator=(const thread&);
+public:
+    typedef __thread_id id;
+    typedef __libcpp_thread_t native_handle_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    thread() _NOEXCEPT : __t_(_LIBCPP_NULL_THREAD) {}
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _Fp, class ..._Args,
+              class = typename enable_if
+              <
+                   !is_same<typename __uncvref<_Fp>::type, thread>::value
+              >::type
+             >
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+        explicit thread(_Fp&& __f, _Args&&... __args);
+#else  // _LIBCPP_CXX03_LANG
+    template <class _Fp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    explicit thread(_Fp __f);
+#endif
+    ~thread();
+
+    _LIBCPP_INLINE_VISIBILITY
+    thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) {
+        __t.__t_ = _LIBCPP_NULL_THREAD;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    thread& operator=(thread&& __t) _NOEXCEPT {
+        if (!__libcpp_thread_isnull(&__t_))
+            terminate();
+        __t_ = __t.__t_;
+        __t.__t_ = _LIBCPP_NULL_THREAD;
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(thread& __t) _NOEXCEPT {_VSTD::swap(__t_, __t.__t_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool joinable() const _NOEXCEPT {return !__libcpp_thread_isnull(&__t_);}
+    void join();
+    void detach();
+    _LIBCPP_INLINE_VISIBILITY
+    id get_id() const _NOEXCEPT {return __libcpp_thread_get_id(&__t_);}
+    _LIBCPP_INLINE_VISIBILITY
+    native_handle_type native_handle() _NOEXCEPT {return __t_;}
+
+    static unsigned hardware_concurrency() _NOEXCEPT;
+};
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _TSp, class _Fp, class ..._Args, size_t ..._Indices>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+__thread_execute(tuple<_TSp, _Fp, _Args...>& __t, __tuple_indices<_Indices...>)
+{
+    _VSTD::__invoke(_VSTD::move(_VSTD::get<1>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
+}
+
+template <class _Fp>
+_LIBCPP_INLINE_VISIBILITY
+void* __thread_proxy(void* __vp)
+{
+    // _Fp = tuple< unique_ptr<__thread_struct>, Functor, Args...>
+    unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
+    __thread_local_data().set_pointer(_VSTD::get<0>(*__p.get()).release());
+    typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 2>::type _Index;
+    _VSTD::__thread_execute(*__p.get(), _Index());
+    return nullptr;
+}
+
+template <class _Fp, class ..._Args,
+          class
+         >
+thread::thread(_Fp&& __f, _Args&&... __args)
+{
+    typedef unique_ptr<__thread_struct> _TSPtr;
+    _TSPtr __tsp(new __thread_struct);
+    typedef tuple<_TSPtr, typename decay<_Fp>::type, typename decay<_Args>::type...> _Gp;
+    unique_ptr<_Gp> __p(
+            new _Gp(_VSTD::move(__tsp),
+                    _VSTD::__decay_copy(_VSTD::forward<_Fp>(__f)),
+                    _VSTD::__decay_copy(_VSTD::forward<_Args>(__args))...));
+    int __ec = _VSTD::__libcpp_thread_create(&__t_, &__thread_proxy<_Gp>, __p.get());
+    if (__ec == 0)
+        __p.release();
+    else
+        __throw_system_error(__ec, "thread constructor failed");
+}
+
+#else  // _LIBCPP_CXX03_LANG
+
+template <class _Fp>
+struct __thread_invoke_pair {
+    // This type is used to pass memory for thread local storage and a functor
+    // to a newly created thread because std::pair doesn't work with
+    // std::unique_ptr in C++03.
+    __thread_invoke_pair(_Fp& __f) : __tsp_(new __thread_struct), __fn_(__f) {}
+    unique_ptr<__thread_struct> __tsp_;
+    _Fp __fn_;
+};
+
+template <class _Fp>
+void* __thread_proxy_cxx03(void* __vp)
+{
+    unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
+    __thread_local_data().set_pointer(__p->__tsp_.release());
+    (__p->__fn_)();
+    return nullptr;
+}
+
+template <class _Fp>
+thread::thread(_Fp __f)
+{
+
+    typedef __thread_invoke_pair<_Fp> _InvokePair;
+    typedef unique_ptr<_InvokePair> _PairPtr;
+    _PairPtr __pp(new _InvokePair(__f));
+    int __ec = _VSTD::__libcpp_thread_create(&__t_, &__thread_proxy_cxx03<_InvokePair>, __pp.get());
+    if (__ec == 0)
+        __pp.release();
+    else
+        __throw_system_error(__ec, "thread constructor failed");
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+inline _LIBCPP_INLINE_VISIBILITY
+void swap(thread& __x, thread& __y) _NOEXCEPT {__x.swap(__y);}
+
+namespace this_thread
+{
+
+_LIBCPP_FUNC_VIS void sleep_for(const chrono::nanoseconds& __ns);
+
+template <class _Rep, class _Period>
+void
+sleep_for(const chrono::duration<_Rep, _Period>& __d)
+{
+    if (__d > chrono::duration<_Rep, _Period>::zero())
+    {
+        // The standard guarantees a 64bit signed integer resolution for nanoseconds,
+        // so use INT64_MAX / 1e9 as cut-off point. Use a constant to avoid <climits>
+        // and issues with long double folding on PowerPC with GCC.
+        _LIBCPP_CONSTEXPR chrono::duration<long double> _Max =
+            chrono::duration<long double>(9223372036.0L);
+        chrono::nanoseconds __ns;
+        if (__d < _Max)
+        {
+            __ns = chrono::duration_cast<chrono::nanoseconds>(__d);
+            if (__ns < __d)
+                ++__ns;
+        }
+        else
+            __ns = chrono::nanoseconds::max();
+        this_thread::sleep_for(__ns);
+    }
+}
+
+template <class _Clock, class _Duration>
+void
+sleep_until(const chrono::time_point<_Clock, _Duration>& __t)
+{
+    mutex __mut;
+    condition_variable __cv;
+    unique_lock<mutex> __lk(__mut);
+    while (_Clock::now() < __t)
+        __cv.wait_until(__lk, __t);
+}
+
+template <class _Duration>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+sleep_until(const chrono::time_point<chrono::steady_clock, _Duration>& __t)
+{
+    this_thread::sleep_for(__t - chrono::steady_clock::now());
+}
+
+inline _LIBCPP_INLINE_VISIBILITY
+void yield() _NOEXCEPT {__libcpp_thread_yield();}
+
+}  // this_thread
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !_LIBCPP_HAS_NO_THREADS
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_THREAD
diff --git a/contrib/libs/cxxsupp/libcxx/include/tuple b/contrib/libs/cxxsupp/libcxx/include/tuple
new file mode 100644
index 00000000000..be57f984dd6
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/tuple
@@ -0,0 +1,1625 @@
+// -*- C++ -*-
+//===--------------------------- tuple ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_TUPLE
+#define _LIBCPP_TUPLE
+
+/*
+    tuple synopsis
+
+namespace std
+{
+
+template <class... T>
+class tuple {
+public:
+    explicit(see-below) constexpr tuple();
+    explicit(see-below) tuple(const T&...);  // constexpr in C++14
+    template <class... U>
+        explicit(see-below) tuple(U&&...);  // constexpr in C++14
+    tuple(const tuple&) = default;
+    tuple(tuple&&) = default;
+    template <class... U>
+        explicit(see-below) tuple(const tuple<U...>&);  // constexpr in C++14
+    template <class... U>
+        explicit(see-below) tuple(tuple<U...>&&);  // constexpr in C++14
+    template <class U1, class U2>
+        explicit(see-below) tuple(const pair<U1, U2>&); // iff sizeof...(T) == 2 // constexpr in C++14
+    template <class U1, class U2>
+        explicit(see-below) tuple(pair<U1, U2>&&); // iff sizeof...(T) == 2  // constexpr in C++14
+
+    // allocator-extended constructors
+    template <class Alloc>
+        tuple(allocator_arg_t, const Alloc& a);
+    template <class Alloc>
+        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const T&...);          // constexpr in C++20
+    template <class Alloc, class... U>
+        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, U&&...);               // constexpr in C++20
+    template <class Alloc>
+        tuple(allocator_arg_t, const Alloc& a, const tuple&);                             // constexpr in C++20
+    template <class Alloc>
+        tuple(allocator_arg_t, const Alloc& a, tuple&&);                                  // constexpr in C++20
+    template <class Alloc, class... U>
+        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const tuple<U...>&);   // constexpr in C++20
+    template <class Alloc, class... U>
+        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, tuple<U...>&&);        // constexpr in C++20
+    template <class Alloc, class U1, class U2>
+        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&);  // constexpr in C++20
+    template <class Alloc, class U1, class U2>
+        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&&);       // constexpr in C++20
+
+    tuple& operator=(const tuple&);                                                       // constexpr in C++20
+    tuple& operator=(tuple&&) noexcept(is_nothrow_move_assignable_v<T> && ...);           // constexpr in C++20
+    template <class... U>
+        tuple& operator=(const tuple<U...>&);                                             // constexpr in C++20
+    template <class... U>
+        tuple& operator=(tuple<U...>&&);                                                  // constexpr in C++20
+    template <class U1, class U2>
+        tuple& operator=(const pair<U1, U2>&); // iff sizeof...(T) == 2                   // constexpr in C++20
+    template <class U1, class U2>
+        tuple& operator=(pair<U1, U2>&&); // iff sizeof...(T) == 2                        // constexpr in C++20
+
+    template<class U, size_t N>
+        tuple& operator=(array<U, N> const&) // iff sizeof...(T) == N, EXTENSION
+    template<class U, size_t N>
+        tuple& operator=(array<U, N>&&) // iff sizeof...(T) == N, EXTENSION
+
+    void swap(tuple&) noexcept(AND(swap(declval<T&>(), declval<T&>())...));               // constexpr in C++20
+};
+
+template <class ...T>
+tuple(T...) -> tuple<T...>;                                         // since C++17
+template <class T1, class T2>
+tuple(pair<T1, T2>) -> tuple<T1, T2>;                               // since C++17
+template <class Alloc, class ...T>
+tuple(allocator_arg_t, Alloc, T...) -> tuple<T...>;                 // since C++17
+template <class Alloc, class T1, class T2>
+tuple(allocator_arg_t, Alloc, pair<T1, T2>) -> tuple<T1, T2>;       // since C++17
+template <class Alloc, class ...T>
+tuple(allocator_arg_t, Alloc, tuple<T...>) -> tuple<T...>;          // since C++17
+
+inline constexpr unspecified ignore;
+
+template <class... T> tuple<V...>  make_tuple(T&&...); // constexpr in C++14
+template <class... T> tuple<ATypes...> forward_as_tuple(T&&...) noexcept; // constexpr in C++14
+template <class... T> tuple<T&...> tie(T&...) noexcept; // constexpr in C++14
+template <class... Tuples> tuple<CTypes...> tuple_cat(Tuples&&... tpls); // constexpr in C++14
+
+// [tuple.apply], calling a function with a tuple of arguments:
+template <class F, class Tuple>
+  constexpr decltype(auto) apply(F&& f, Tuple&& t); // C++17
+template <class T, class Tuple>
+  constexpr T make_from_tuple(Tuple&& t); // C++17
+
+// 20.4.1.4, tuple helper classes:
+template <class T> struct tuple_size; // undefined
+template <class... T> struct tuple_size<tuple<T...>>;
+template <class T>
+ inline constexpr size_t tuple_size_v = tuple_size<T>::value; // C++17
+template <size_t I, class T> struct tuple_element; // undefined
+template <size_t I, class... T> struct tuple_element<I, tuple<T...>>;
+template <size_t I, class T>
+  using tuple_element_t = typename tuple_element <I, T>::type; // C++14
+
+// 20.4.1.5, element access:
+template <size_t I, class... T>
+    typename tuple_element<I, tuple<T...>>::type&
+    get(tuple<T...>&) noexcept; // constexpr in C++14
+template <size_t I, class... T>
+    const typename tuple_element<I, tuple<T...>>::type&
+    get(const tuple<T...>&) noexcept; // constexpr in C++14
+template <size_t I, class... T>
+    typename tuple_element<I, tuple<T...>>::type&&
+    get(tuple<T...>&&) noexcept; // constexpr in C++14
+template <size_t I, class... T>
+    const typename tuple_element<I, tuple<T...>>::type&&
+    get(const tuple<T...>&&) noexcept; // constexpr in C++14
+
+template <class T1, class... T>
+    constexpr T1& get(tuple<T...>&) noexcept;  // C++14
+template <class T1, class... T>
+    constexpr const T1& get(const tuple<T...>&) noexcept;   // C++14
+template <class T1, class... T>
+    constexpr T1&& get(tuple<T...>&&) noexcept;   // C++14
+template <class T1, class... T>
+    constexpr const T1&& get(const tuple<T...>&&) noexcept;   // C++14
+
+// 20.4.1.6, relational operators:
+template<class... T, class... U> bool operator==(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
+template<class... T, class... U> bool operator<(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14, removed in C++20
+template<class... T, class... U> bool operator!=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
+template<class... T, class... U> bool operator>(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14, removed in C++20
+template<class... T, class... U> bool operator<=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
+template<class... T, class... U> bool operator>=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
+template<class... T, class... U>
+  constexpr common_comparison_category_t<synth-three-way-result<T, U>...>
+    operator<=>(const tuple<T...>&, const tuple<U...>&);                                  // since C++20
+
+template <class... Types, class Alloc>
+  struct uses_allocator<tuple<Types...>, Alloc>;
+
+template <class... Types>
+  void
+  swap(tuple<Types...>& x, tuple<Types...>& y) noexcept(noexcept(x.swap(y)));
+
+}  // std
+
+*/
+
+#include <__compare/common_comparison_category.h>
+#include <__compare/synth_three_way.h>
+#include <__config>
+#include <__functional/unwrap_ref.h>
+#include <__functional_base>
+#include <__memory/allocator_arg_t.h>
+#include <__memory/uses_allocator.h>
+#include <__tuple>
+#include <__utility/forward.h>
+#include <__utility/integer_sequence.h>
+#include <__utility/move.h>
+#include <compare>
+#include <cstddef>
+#include <type_traits>
+#include <utility>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_CXX03_LANG
+
+
+// __tuple_leaf
+
+template <size_t _Ip, class _Hp,
+          bool=is_empty<_Hp>::value && !__libcpp_is_final<_Hp>::value
+         >
+class __tuple_leaf;
+
+template <size_t _Ip, class _Hp, bool _Ep>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+void swap(__tuple_leaf<_Ip, _Hp, _Ep>& __x, __tuple_leaf<_Ip, _Hp, _Ep>& __y)
+    _NOEXCEPT_(__is_nothrow_swappable<_Hp>::value)
+{
+    swap(__x.get(), __y.get());
+}
+
+template <size_t _Ip, class _Hp, bool>
+class __tuple_leaf
+{
+    _Hp __value_;
+
+    template <class _Tp>
+    static constexpr bool __can_bind_reference() {
+#if __has_keyword(__reference_binds_to_temporary) && !defined(__CUDACC__)
+      return !__reference_binds_to_temporary(_Hp, _Tp);
+#else
+      return true;
+#endif
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11
+    __tuple_leaf& operator=(const __tuple_leaf&);
+public:
+    _LIBCPP_INLINE_VISIBILITY constexpr __tuple_leaf()
+             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) : __value_()
+       {static_assert(!is_reference<_Hp>::value,
+              "Attempted to default construct a reference element in a tuple");}
+
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY constexpr
+        __tuple_leaf(integral_constant<int, 0>, const _Alloc&)
+            : __value_()
+        {static_assert(!is_reference<_Hp>::value,
+              "Attempted to default construct a reference element in a tuple");}
+
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY constexpr
+        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
+            : __value_(allocator_arg_t(), __a)
+        {static_assert(!is_reference<_Hp>::value,
+              "Attempted to default construct a reference element in a tuple");}
+
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY constexpr
+        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
+            : __value_(__a)
+        {static_assert(!is_reference<_Hp>::value,
+              "Attempted to default construct a reference element in a tuple");}
+
+    template <class _Tp,
+              class = __enable_if_t<
+                  _And<
+                      _IsNotSame<__uncvref_t<_Tp>, __tuple_leaf>,
+                      is_constructible<_Hp, _Tp>
+                    >::value
+                >
+            >
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
+            : __value_(_VSTD::forward<_Tp>(__t))
+        {static_assert(__can_bind_reference<_Tp&&>(),
+       "Attempted construction of reference element binds to a temporary whose lifetime has ended");}
+
+    template <class _Tp, class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
+            : __value_(_VSTD::forward<_Tp>(__t))
+        {static_assert(__can_bind_reference<_Tp&&>(),
+       "Attempted construction of reference element binds to a temporary whose lifetime has ended");}
+
+    template <class _Tp, class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
+            : __value_(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t))
+        {static_assert(!is_reference<_Hp>::value,
+            "Attempted to uses-allocator construct a reference element in a tuple");}
+
+    template <class _Tp, class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
+            : __value_(_VSTD::forward<_Tp>(__t), __a)
+        {static_assert(!is_reference<_Hp>::value,
+           "Attempted to uses-allocator construct a reference element in a tuple");}
+
+    __tuple_leaf(const __tuple_leaf& __t) = default;
+    __tuple_leaf(__tuple_leaf&& __t) = default;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    int swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
+    {
+        _VSTD::swap(*this, __t);
+        return 0;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11       _Hp& get()       _NOEXCEPT {return __value_;}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const _Hp& get() const _NOEXCEPT {return __value_;}
+};
+
+template <size_t _Ip, class _Hp>
+class __tuple_leaf<_Ip, _Hp, true>
+    : private _Hp
+{
+    _LIBCPP_CONSTEXPR_AFTER_CXX11
+    __tuple_leaf& operator=(const __tuple_leaf&);
+public:
+    _LIBCPP_INLINE_VISIBILITY constexpr __tuple_leaf()
+             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) {}
+
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY constexpr
+        __tuple_leaf(integral_constant<int, 0>, const _Alloc&) {}
+
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY constexpr
+        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
+            : _Hp(allocator_arg_t(), __a) {}
+
+    template <class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY constexpr
+        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
+            : _Hp(__a) {}
+
+    template <class _Tp,
+              class = __enable_if_t<
+                  _And<
+                    _IsNotSame<__uncvref_t<_Tp>, __tuple_leaf>,
+                    is_constructible<_Hp, _Tp>
+                  >::value
+                >
+            >
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
+            : _Hp(_VSTD::forward<_Tp>(__t)) {}
+
+    template <class _Tp, class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY constexpr
+        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
+            : _Hp(_VSTD::forward<_Tp>(__t)) {}
+
+    template <class _Tp, class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY constexpr
+        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
+            : _Hp(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t)) {}
+
+    template <class _Tp, class _Alloc>
+        _LIBCPP_INLINE_VISIBILITY constexpr
+        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
+            : _Hp(_VSTD::forward<_Tp>(__t), __a) {}
+
+    __tuple_leaf(__tuple_leaf const &) = default;
+    __tuple_leaf(__tuple_leaf &&) = default;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    int
+    swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
+    {
+        _VSTD::swap(*this, __t);
+        return 0;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11       _Hp& get()       _NOEXCEPT {return static_cast<_Hp&>(*this);}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const _Hp& get() const _NOEXCEPT {return static_cast<const _Hp&>(*this);}
+};
+
+template <class ..._Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+void __swallow(_Tp&&...) _NOEXCEPT {}
+
+template <class _Tp>
+struct __all_default_constructible;
+
+template <class ..._Tp>
+struct __all_default_constructible<__tuple_types<_Tp...>>
+    : __all<is_default_constructible<_Tp>::value...>
+{ };
+
+// __tuple_impl
+
+template<class _Indx, class ..._Tp> struct __tuple_impl;
+
+template<size_t ..._Indx, class ..._Tp>
+struct _LIBCPP_DECLSPEC_EMPTY_BASES __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
+    : public __tuple_leaf<_Indx, _Tp>...
+{
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr __tuple_impl()
+        _NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
+
+    template <size_t ..._Uf, class ..._Tf,
+              size_t ..._Ul, class ..._Tl, class ..._Up>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+        explicit
+        __tuple_impl(__tuple_indices<_Uf...>, __tuple_types<_Tf...>,
+                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
+                     _Up&&... __u)
+                     _NOEXCEPT_((__all<is_nothrow_constructible<_Tf, _Up>::value...>::value &&
+                                 __all<is_nothrow_default_constructible<_Tl>::value...>::value)) :
+            __tuple_leaf<_Uf, _Tf>(_VSTD::forward<_Up>(__u))...,
+            __tuple_leaf<_Ul, _Tl>()...
+            {}
+
+#if defined(__NVCC__) && defined(_LIBCPP_COMPILER_MSVC)
+    // Yandex-specific: specialize the preceding constructor for the
+    // case of empty _Ul and _Tl to work around nvcc+msvc bug
+    // compiling libcxx std::map<int, int> m; m[1] = 2.
+    template <size_t ..._Uf, class ..._Tf,
+              class ..._Up>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+        explicit
+        __tuple_impl(__tuple_indices<_Uf...>, __tuple_types<_Tf...>,
+                     __tuple_indices<>, __tuple_types<>,
+                     _Up&&... __u)
+                     _NOEXCEPT_((__all<is_nothrow_constructible<_Tf, _Up>::value...>::value)) :
+            __tuple_leaf<_Uf, _Tf>(_VSTD::forward<_Up>(__u))...
+            {}
+    // End of Yandex-specific
+#endif
+
+    template <class _Alloc, size_t ..._Uf, class ..._Tf,
+              size_t ..._Ul, class ..._Tl, class ..._Up>
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+        explicit
+        __tuple_impl(allocator_arg_t, const _Alloc& __a,
+                     __tuple_indices<_Uf...>, __tuple_types<_Tf...>,
+                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
+                     _Up&&... __u) :
+            __tuple_leaf<_Uf, _Tf>(__uses_alloc_ctor<_Tf, _Alloc, _Up>(), __a,
+            _VSTD::forward<_Up>(__u))...,
+            __tuple_leaf<_Ul, _Tl>(__uses_alloc_ctor<_Tl, _Alloc>(), __a)...
+            {}
+
+    template <class _Tuple,
+              class = typename enable_if
+                      <
+                         __tuple_constructible<_Tuple, tuple<_Tp...> >::value
+                      >::type
+             >
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+        __tuple_impl(_Tuple&& __t) _NOEXCEPT_((__all<is_nothrow_constructible<_Tp, typename tuple_element<_Indx,
+                                       typename __make_tuple_types<_Tuple>::type>::type>::value...>::value))
+            : __tuple_leaf<_Indx, _Tp>(_VSTD::forward<typename tuple_element<_Indx,
+                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
+            {}
+
+    template <class _Alloc, class _Tuple,
+              class = typename enable_if
+                      <
+                         __tuple_constructible<_Tuple, tuple<_Tp...> >::value
+                      >::type
+             >
+        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+        __tuple_impl(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
+            : __tuple_leaf<_Indx, _Tp>(__uses_alloc_ctor<_Tp, _Alloc, typename tuple_element<_Indx,
+                                       typename __make_tuple_types<_Tuple>::type>::type>(), __a,
+                                       _VSTD::forward<typename tuple_element<_Indx,
+                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
+            {}
+
+    __tuple_impl(const __tuple_impl&) = default;
+    __tuple_impl(__tuple_impl&&) = default;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    void swap(__tuple_impl& __t)
+        _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
+    {
+        _VSTD::__swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t))...);
+    }
+};
+
+template<class _Dest, class _Source, size_t ..._Np>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+void __memberwise_copy_assign(_Dest& __dest, _Source const& __source, __tuple_indices<_Np...>) {
+    _VSTD::__swallow(((_VSTD::get<_Np>(__dest) = _VSTD::get<_Np>(__source)), void(), 0)...);
+    }
+
+template<class _Dest, class _Source, class ..._Up, size_t ..._Np>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+void __memberwise_forward_assign(_Dest& __dest, _Source&& __source, __tuple_types<_Up...>, __tuple_indices<_Np...>) {
+    _VSTD::__swallow(((
+        _VSTD::get<_Np>(__dest) = _VSTD::forward<_Up>(_VSTD::get<_Np>(__source))
+    ), void(), 0)...);
+    }
+
+template <class ..._Tp>
+class _LIBCPP_TEMPLATE_VIS tuple
+{
+    typedef __tuple_impl<typename __make_tuple_indices<sizeof...(_Tp)>::type, _Tp...> _BaseT;
+
+    _BaseT __base_;
+
+    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
+        typename tuple_element<_Jp, tuple<_Up...> >::type& get(tuple<_Up...>&) _NOEXCEPT;
+    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
+        const typename tuple_element<_Jp, tuple<_Up...> >::type& get(const tuple<_Up...>&) _NOEXCEPT;
+    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
+        typename tuple_element<_Jp, tuple<_Up...> >::type&& get(tuple<_Up...>&&) _NOEXCEPT;
+    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
+        const typename tuple_element<_Jp, tuple<_Up...> >::type&& get(const tuple<_Up...>&&) _NOEXCEPT;
+public:
+    // [tuple.cnstr]
+
+    // tuple() constructors (including allocator_arg_t variants)
+    template <template<class...> class _IsImpDefault = __is_implicitly_default_constructible, __enable_if_t<
+        _And<
+            _IsImpDefault<_Tp>... // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    tuple()
+        _NOEXCEPT_(_And<is_nothrow_default_constructible<_Tp>...>::value)
+    { }
+
+    template <template<class...> class _IsImpDefault = __is_implicitly_default_constructible,
+              template<class...> class _IsDefault = is_default_constructible, __enable_if_t<
+        _And<
+            _IsDefault<_Tp>...,
+            _Not<_Lazy<_And, _IsImpDefault<_Tp>...> > // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    explicit tuple()
+        _NOEXCEPT_(_And<is_nothrow_default_constructible<_Tp>...>::value)
+    { }
+
+    template <class _Alloc, template<class...> class _IsImpDefault = __is_implicitly_default_constructible, __enable_if_t<
+        _And<
+            _IsImpDefault<_Tp>... // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple(allocator_arg_t, _Alloc const& __a)
+      : __base_(allocator_arg_t(), __a,
+                    __tuple_indices<>(), __tuple_types<>(),
+                    typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
+                    __tuple_types<_Tp...>()) {}
+
+    template <class _Alloc,
+              template<class...> class _IsImpDefault = __is_implicitly_default_constructible,
+              template<class...> class _IsDefault = is_default_constructible, __enable_if_t<
+        _And<
+            _IsDefault<_Tp>...,
+            _Not<_Lazy<_And, _IsImpDefault<_Tp>...> > // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    explicit tuple(allocator_arg_t, _Alloc const& __a)
+      : __base_(allocator_arg_t(), __a,
+                    __tuple_indices<>(), __tuple_types<>(),
+                    typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
+                    __tuple_types<_Tp...>()) {}
+
+    // tuple(const T&...) constructors (including allocator_arg_t variants)
+    template <template<class...> class _And = _And, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) >= 1>,
+            is_copy_constructible<_Tp>...,
+            is_convertible<const _Tp&, _Tp>... // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    tuple(const _Tp& ... __t)
+        _NOEXCEPT_(_And<is_nothrow_copy_constructible<_Tp>...>::value)
+        : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
+                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
+                typename __make_tuple_indices<0>::type(),
+                typename __make_tuple_types<tuple, 0>::type(),
+                __t...
+               ) {}
+
+    template <template<class...> class _And = _And, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) >= 1>,
+            is_copy_constructible<_Tp>...,
+            _Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> > // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit tuple(const _Tp& ... __t)
+        _NOEXCEPT_(_And<is_nothrow_copy_constructible<_Tp>...>::value)
+        : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
+                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
+                typename __make_tuple_indices<0>::type(),
+                typename __make_tuple_types<tuple, 0>::type(),
+                __t...
+               ) {}
+
+    template <class _Alloc, template<class...> class _And = _And, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) >= 1>,
+            is_copy_constructible<_Tp>...,
+            is_convertible<const _Tp&, _Tp>... // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
+        : __base_(allocator_arg_t(), __a,
+                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
+                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
+                typename __make_tuple_indices<0>::type(),
+                typename __make_tuple_types<tuple, 0>::type(),
+                __t...
+               ) {}
+
+    template <class _Alloc, template<class...> class _And = _And, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) >= 1>,
+            is_copy_constructible<_Tp>...,
+            _Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> > // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    explicit tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
+        : __base_(allocator_arg_t(), __a,
+                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
+                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
+                typename __make_tuple_indices<0>::type(),
+                typename __make_tuple_types<tuple, 0>::type(),
+                __t...
+               ) {}
+
+    // tuple(U&& ...) constructors (including allocator_arg_t variants)
+    template <class ..._Up> struct _IsThisTuple : false_type { };
+    template <class _Up> struct _IsThisTuple<_Up> : is_same<__uncvref_t<_Up>, tuple> { };
+
+    template <class ..._Up>
+    struct _EnableUTypesCtor : _And<
+        _BoolConstant<sizeof...(_Tp) >= 1>,
+        _Not<_IsThisTuple<_Up...> >, // extension to allow mis-behaved user constructors
+        is_constructible<_Tp, _Up>...
+    > { };
+
+    template <class ..._Up, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
+            _EnableUTypesCtor<_Up...>,
+            is_convertible<_Up, _Tp>... // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    tuple(_Up&&... __u)
+        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
+        : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
+                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
+                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
+                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
+                    _VSTD::forward<_Up>(__u)...) {}
+
+    template <class ..._Up, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
+            _EnableUTypesCtor<_Up...>,
+            _Not<_Lazy<_And, is_convertible<_Up, _Tp>...> > // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit tuple(_Up&&... __u)
+        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
+        : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
+                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
+                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
+                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
+                    _VSTD::forward<_Up>(__u)...) {}
+
+    template <class _Alloc, class ..._Up, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
+            _EnableUTypesCtor<_Up...>,
+            is_convertible<_Up, _Tp>... // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
+        : __base_(allocator_arg_t(), __a,
+                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
+                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
+                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
+                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
+                    _VSTD::forward<_Up>(__u)...) {}
+
+    template <class _Alloc, class ..._Up, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
+            _EnableUTypesCtor<_Up...>,
+            _Not<_Lazy<_And, is_convertible<_Up, _Tp>...> > // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    explicit tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
+        : __base_(allocator_arg_t(), __a,
+                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
+                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
+                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
+                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
+                    _VSTD::forward<_Up>(__u)...) {}
+
+    // Copy and move constructors (including the allocator_arg_t variants)
+    tuple(const tuple&) = default;
+    tuple(tuple&&) = default;
+
+    template <class _Alloc, template<class...> class _And = _And, __enable_if_t<
+        _And<is_copy_constructible<_Tp>...>::value
+    , int> = 0>
+    tuple(allocator_arg_t, const _Alloc& __alloc, const tuple& __t)
+        : __base_(allocator_arg_t(), __alloc, __t)
+    { }
+
+    template <class _Alloc, template<class...> class _And = _And, __enable_if_t<
+        _And<is_move_constructible<_Tp>...>::value
+    , int> = 0>
+    tuple(allocator_arg_t, const _Alloc& __alloc, tuple&& __t)
+        : __base_(allocator_arg_t(), __alloc, _VSTD::move(__t))
+    { }
+
+    // tuple(const tuple<U...>&) constructors (including allocator_arg_t variants)
+    template <class ..._Up>
+    struct _EnableCopyFromOtherTuple : _And<
+        _Not<is_same<tuple<_Tp...>, tuple<_Up...> > >,
+        _Lazy<_Or,
+            _BoolConstant<sizeof...(_Tp) != 1>,
+            // _Tp and _Up are 1-element packs - the pack expansions look
+            // weird to avoid tripping up the type traits in degenerate cases
+            _Lazy<_And,
+                _Not<is_convertible<const tuple<_Up>&, _Tp> >...,
+                _Not<is_constructible<_Tp, const tuple<_Up>&> >...
+            >
+        >,
+        is_constructible<_Tp, const _Up&>...
+    > { };
+
+    template <class ..._Up, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
+            _EnableCopyFromOtherTuple<_Up...>,
+            is_convertible<const _Up&, _Tp>... // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    tuple(const tuple<_Up...>& __t)
+        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, const _Up&>...>::value))
+        : __base_(__t)
+    { }
+
+    template <class ..._Up, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
+            _EnableCopyFromOtherTuple<_Up...>,
+            _Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> > // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit tuple(const tuple<_Up...>& __t)
+        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, const _Up&>...>::value))
+        : __base_(__t)
+    { }
+
+    template <class ..._Up, class _Alloc, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
+            _EnableCopyFromOtherTuple<_Up...>,
+            is_convertible<const _Up&, _Tp>... // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple(allocator_arg_t, const _Alloc& __a, const tuple<_Up...>& __t)
+        : __base_(allocator_arg_t(), __a, __t)
+    { }
+
+    template <class ..._Up, class _Alloc, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
+            _EnableCopyFromOtherTuple<_Up...>,
+            _Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> > // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    explicit tuple(allocator_arg_t, const _Alloc& __a, const tuple<_Up...>& __t)
+        : __base_(allocator_arg_t(), __a, __t)
+    { }
+
+    // tuple(tuple<U...>&&) constructors (including allocator_arg_t variants)
+    template <class ..._Up>
+    struct _EnableMoveFromOtherTuple : _And<
+        _Not<is_same<tuple<_Tp...>, tuple<_Up...> > >,
+        _Lazy<_Or,
+            _BoolConstant<sizeof...(_Tp) != 1>,
+            // _Tp and _Up are 1-element packs - the pack expansions look
+            // weird to avoid tripping up the type traits in degenerate cases
+            _Lazy<_And,
+                _Not<is_convertible<tuple<_Up>, _Tp> >...,
+                _Not<is_constructible<_Tp, tuple<_Up> > >...
+            >
+        >,
+        is_constructible<_Tp, _Up>...
+    > { };
+
+    template <class ..._Up, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
+            _EnableMoveFromOtherTuple<_Up...>,
+            is_convertible<_Up, _Tp>... // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    tuple(tuple<_Up...>&& __t)
+        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
+        : __base_(_VSTD::move(__t))
+    { }
+
+    template <class ..._Up, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
+            _EnableMoveFromOtherTuple<_Up...>,
+            _Not<_Lazy<_And, is_convertible<_Up, _Tp>...> > // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit tuple(tuple<_Up...>&& __t)
+        _NOEXCEPT_((_And<is_nothrow_constructible<_Tp, _Up>...>::value))
+        : __base_(_VSTD::move(__t))
+    { }
+
+    template <class _Alloc, class ..._Up, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
+            _EnableMoveFromOtherTuple<_Up...>,
+            is_convertible<_Up, _Tp>... // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple(allocator_arg_t, const _Alloc& __a, tuple<_Up...>&& __t)
+        : __base_(allocator_arg_t(), __a, _VSTD::move(__t))
+    { }
+
+    template <class _Alloc, class ..._Up, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>,
+            _EnableMoveFromOtherTuple<_Up...>,
+            _Not<_Lazy<_And, is_convertible<_Up, _Tp>...> > // explicit check
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    explicit tuple(allocator_arg_t, const _Alloc& __a, tuple<_Up...>&& __t)
+        : __base_(allocator_arg_t(), __a, _VSTD::move(__t))
+    { }
+
+    // tuple(const pair<U1, U2>&) constructors (including allocator_arg_t variants)
+    template <class _Up1, class _Up2, class ..._DependentTp>
+    struct _EnableImplicitCopyFromPair : _And<
+        is_constructible<_FirstType<_DependentTp...>, const _Up1&>,
+        is_constructible<_SecondType<_DependentTp...>, const _Up2&>,
+        is_convertible<const _Up1&, _FirstType<_DependentTp...> >, // explicit check
+        is_convertible<const _Up2&, _SecondType<_DependentTp...> >
+    > { };
+
+    template <class _Up1, class _Up2, class ..._DependentTp>
+    struct _EnableExplicitCopyFromPair : _And<
+        is_constructible<_FirstType<_DependentTp...>, const _Up1&>,
+        is_constructible<_SecondType<_DependentTp...>, const _Up2&>,
+        _Not<is_convertible<const _Up1&, _FirstType<_DependentTp...> > >, // explicit check
+        _Not<is_convertible<const _Up2&, _SecondType<_DependentTp...> > >
+    > { };
+
+    template <class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) == 2>,
+            _EnableImplicitCopyFromPair<_Up1, _Up2, _Tp...>
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    tuple(const pair<_Up1, _Up2>& __p)
+        _NOEXCEPT_((_And<
+            is_nothrow_constructible<_FirstType<_Tp...>, const _Up1&>,
+            is_nothrow_constructible<_SecondType<_Tp...>, const _Up2&>
+        >::value))
+        : __base_(__p)
+    { }
+
+    template <class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) == 2>,
+            _EnableExplicitCopyFromPair<_Up1, _Up2, _Tp...>
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit tuple(const pair<_Up1, _Up2>& __p)
+        _NOEXCEPT_((_And<
+            is_nothrow_constructible<_FirstType<_Tp...>, const _Up1&>,
+            is_nothrow_constructible<_SecondType<_Tp...>, const _Up2&>
+        >::value))
+        : __base_(__p)
+    { }
+
+    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) == 2>,
+            _EnableImplicitCopyFromPair<_Up1, _Up2, _Tp...>
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple(allocator_arg_t, const _Alloc& __a, const pair<_Up1, _Up2>& __p)
+        : __base_(allocator_arg_t(), __a, __p)
+    { }
+
+    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) == 2>,
+            _EnableExplicitCopyFromPair<_Up1, _Up2, _Tp...>
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    explicit tuple(allocator_arg_t, const _Alloc& __a, const pair<_Up1, _Up2>& __p)
+        : __base_(allocator_arg_t(), __a, __p)
+    { }
+
+    // tuple(pair<U1, U2>&&) constructors (including allocator_arg_t variants)
+    template <class _Up1, class _Up2, class ..._DependentTp>
+    struct _EnableImplicitMoveFromPair : _And<
+        is_constructible<_FirstType<_DependentTp...>, _Up1>,
+        is_constructible<_SecondType<_DependentTp...>, _Up2>,
+        is_convertible<_Up1, _FirstType<_DependentTp...> >, // explicit check
+        is_convertible<_Up2, _SecondType<_DependentTp...> >
+    > { };
+
+    template <class _Up1, class _Up2, class ..._DependentTp>
+    struct _EnableExplicitMoveFromPair : _And<
+        is_constructible<_FirstType<_DependentTp...>, _Up1>,
+        is_constructible<_SecondType<_DependentTp...>, _Up2>,
+        _Not<is_convertible<_Up1, _FirstType<_DependentTp...> > >, // explicit check
+        _Not<is_convertible<_Up2, _SecondType<_DependentTp...> > >
+    > { };
+
+    template <class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) == 2>,
+            _EnableImplicitMoveFromPair<_Up1, _Up2, _Tp...>
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    tuple(pair<_Up1, _Up2>&& __p)
+        _NOEXCEPT_((_And<
+            is_nothrow_constructible<_FirstType<_Tp...>, _Up1>,
+            is_nothrow_constructible<_SecondType<_Tp...>, _Up2>
+        >::value))
+        : __base_(_VSTD::move(__p))
+    { }
+
+    template <class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) == 2>,
+            _EnableExplicitMoveFromPair<_Up1, _Up2, _Tp...>
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    explicit tuple(pair<_Up1, _Up2>&& __p)
+        _NOEXCEPT_((_And<
+            is_nothrow_constructible<_FirstType<_Tp...>, _Up1>,
+            is_nothrow_constructible<_SecondType<_Tp...>, _Up2>
+        >::value))
+        : __base_(_VSTD::move(__p))
+    { }
+
+    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) == 2>,
+            _EnableImplicitMoveFromPair<_Up1, _Up2, _Tp...>
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple(allocator_arg_t, const _Alloc& __a, pair<_Up1, _Up2>&& __p)
+        : __base_(allocator_arg_t(), __a, _VSTD::move(__p))
+    { }
+
+    template <class _Alloc, class _Up1, class _Up2, template<class...> class _And = _And, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) == 2>,
+            _EnableExplicitMoveFromPair<_Up1, _Up2, _Tp...>
+        >::value
+    , int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    explicit tuple(allocator_arg_t, const _Alloc& __a, pair<_Up1, _Up2>&& __p)
+        : __base_(allocator_arg_t(), __a, _VSTD::move(__p))
+    { }
+
+    // [tuple.assign]
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple& operator=(_If<_And<is_copy_assignable<_Tp>...>::value, tuple, __nat> const& __tuple)
+        _NOEXCEPT_((_And<is_nothrow_copy_assignable<_Tp>...>::value))
+    {
+        _VSTD::__memberwise_copy_assign(*this, __tuple,
+            typename __make_tuple_indices<sizeof...(_Tp)>::type());
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple& operator=(_If<_And<is_move_assignable<_Tp>...>::value, tuple, __nat>&& __tuple)
+        _NOEXCEPT_((_And<is_nothrow_move_assignable<_Tp>...>::value))
+    {
+        _VSTD::__memberwise_forward_assign(*this, _VSTD::move(__tuple),
+            __tuple_types<_Tp...>(),
+            typename __make_tuple_indices<sizeof...(_Tp)>::type());
+        return *this;
+    }
+
+    template<class... _Up, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>,
+            is_assignable<_Tp&, _Up const&>...
+        >::value
+    ,int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple& operator=(tuple<_Up...> const& __tuple)
+        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value))
+    {
+        _VSTD::__memberwise_copy_assign(*this, __tuple,
+            typename __make_tuple_indices<sizeof...(_Tp)>::type());
+        return *this;
+    }
+
+    template<class... _Up, __enable_if_t<
+        _And<
+            _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>,
+            is_assignable<_Tp&, _Up>...
+        >::value
+    ,int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple& operator=(tuple<_Up...>&& __tuple)
+        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up>...>::value))
+    {
+        _VSTD::__memberwise_forward_assign(*this, _VSTD::move(__tuple),
+            __tuple_types<_Up...>(),
+            typename __make_tuple_indices<sizeof...(_Tp)>::type());
+        return *this;
+    }
+
+    template<class _Up1, class _Up2, class _Dep = true_type, __enable_if_t<
+        _And<_Dep,
+            _BoolConstant<sizeof...(_Tp) == 2>,
+            is_assignable<_FirstType<_Tp..., _Dep>&, _Up1 const&>,
+            is_assignable<_SecondType<_Tp..., _Dep>&, _Up2 const&>
+        >::value
+    ,int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple& operator=(pair<_Up1, _Up2> const& __pair)
+        _NOEXCEPT_((_And<
+            is_nothrow_assignable<_FirstType<_Tp...>&, _Up1 const&>,
+            is_nothrow_assignable<_SecondType<_Tp...>&, _Up2 const&>
+        >::value))
+    {
+        _VSTD::get<0>(*this) = __pair.first;
+        _VSTD::get<1>(*this) = __pair.second;
+        return *this;
+    }
+
+    template<class _Up1, class _Up2, class _Dep = true_type, __enable_if_t<
+        _And<_Dep,
+            _BoolConstant<sizeof...(_Tp) == 2>,
+            is_assignable<_FirstType<_Tp..., _Dep>&, _Up1>,
+            is_assignable<_SecondType<_Tp..., _Dep>&, _Up2>
+        >::value
+    ,int> = 0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple& operator=(pair<_Up1, _Up2>&& __pair)
+        _NOEXCEPT_((_And<
+            is_nothrow_assignable<_FirstType<_Tp...>&, _Up1>,
+            is_nothrow_assignable<_SecondType<_Tp...>&, _Up2>
+        >::value))
+    {
+        _VSTD::get<0>(*this) = _VSTD::forward<_Up1>(__pair.first);
+        _VSTD::get<1>(*this) = _VSTD::forward<_Up2>(__pair.second);
+        return *this;
+    }
+
+    // EXTENSION
+    template<class _Up, size_t _Np, class = __enable_if_t<
+        _And<
+            _BoolConstant<_Np == sizeof...(_Tp)>,
+            is_assignable<_Tp&, _Up const&>...
+        >::value
+    > >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple& operator=(array<_Up, _Np> const& __array)
+        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value))
+    {
+        _VSTD::__memberwise_copy_assign(*this, __array,
+            typename __make_tuple_indices<sizeof...(_Tp)>::type());
+        return *this;
+    }
+
+    // EXTENSION
+    template<class _Up, size_t _Np, class = void, class = __enable_if_t<
+        _And<
+            _BoolConstant<_Np == sizeof...(_Tp)>,
+            is_assignable<_Tp&, _Up>...
+        >::value
+    > >
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    tuple& operator=(array<_Up, _Np>&& __array)
+        _NOEXCEPT_((_And<is_nothrow_assignable<_Tp&, _Up>...>::value))
+    {
+        _VSTD::__memberwise_forward_assign(*this, _VSTD::move(__array),
+            __tuple_types<_If<true, _Up, _Tp>...>(),
+            typename __make_tuple_indices<sizeof...(_Tp)>::type());
+        return *this;
+    }
+
+    // [tuple.swap]
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    void swap(tuple& __t) _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
+        {__base_.swap(__t.__base_);}
+};
+
+template <>
+class _LIBCPP_TEMPLATE_VIS tuple<>
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY constexpr
+        tuple() _NOEXCEPT = default;
+    template <class _Alloc>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+        tuple(allocator_arg_t, const _Alloc&) _NOEXCEPT {}
+    template <class _Alloc>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+        tuple(allocator_arg_t, const _Alloc&, const tuple&) _NOEXCEPT {}
+    template <class _Up>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+        tuple(array<_Up, 0>) _NOEXCEPT {}
+    template <class _Alloc, class _Up>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+        tuple(allocator_arg_t, const _Alloc&, array<_Up, 0>) _NOEXCEPT {}
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    void swap(tuple&) _NOEXCEPT {}
+};
+
+#if _LIBCPP_STD_VER >= 17
+template <class ..._Tp>
+tuple(_Tp...) -> tuple<_Tp...>;
+template <class _Tp1, class _Tp2>
+tuple(pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
+template <class _Alloc, class ..._Tp>
+tuple(allocator_arg_t, _Alloc, _Tp...) -> tuple<_Tp...>;
+template <class _Alloc, class _Tp1, class _Tp2>
+tuple(allocator_arg_t, _Alloc, pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
+template <class _Alloc, class ..._Tp>
+tuple(allocator_arg_t, _Alloc, tuple<_Tp...>) -> tuple<_Tp...>;
+#endif
+
+template <class ..._Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+typename enable_if
+<
+    __all<__is_swappable<_Tp>::value...>::value,
+    void
+>::type
+swap(tuple<_Tp...>& __t, tuple<_Tp...>& __u)
+                 _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
+    {__t.swap(__u);}
+
+// get
+
+template <size_t _Ip, class ..._Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename tuple_element<_Ip, tuple<_Tp...> >::type&
+get(tuple<_Tp...>& __t) _NOEXCEPT
+{
+    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
+    return static_cast<__tuple_leaf<_Ip, type>&>(__t.__base_).get();
+}
+
+template <size_t _Ip, class ..._Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const typename tuple_element<_Ip, tuple<_Tp...> >::type&
+get(const tuple<_Tp...>& __t) _NOEXCEPT
+{
+    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
+    return static_cast<const __tuple_leaf<_Ip, type>&>(__t.__base_).get();
+}
+
+template <size_t _Ip, class ..._Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename tuple_element<_Ip, tuple<_Tp...> >::type&&
+get(tuple<_Tp...>&& __t) _NOEXCEPT
+{
+    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
+    return static_cast<type&&>(
+             static_cast<__tuple_leaf<_Ip, type>&&>(__t.__base_).get());
+}
+
+template <size_t _Ip, class ..._Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+const typename tuple_element<_Ip, tuple<_Tp...> >::type&&
+get(const tuple<_Tp...>&& __t) _NOEXCEPT
+{
+    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
+    return static_cast<const type&&>(
+             static_cast<const __tuple_leaf<_Ip, type>&&>(__t.__base_).get());
+}
+
+#if _LIBCPP_STD_VER > 11
+
+namespace __find_detail {
+
+static constexpr size_t __not_found = static_cast<size_t>(-1);
+static constexpr size_t __ambiguous = __not_found - 1;
+
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr size_t __find_idx_return(size_t __curr_i, size_t __res, bool __matches) {
+    return !__matches ? __res :
+        (__res == __not_found ? __curr_i : __ambiguous);
+}
+
+template <size_t _Nx>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr size_t __find_idx(size_t __i, const bool (&__matches)[_Nx]) {
+  return __i == _Nx ? __not_found :
+      __find_idx_return(__i, __find_idx(__i + 1, __matches), __matches[__i]);
+}
+
+template <class _T1, class ..._Args>
+struct __find_exactly_one_checked {
+    static constexpr bool __matches[sizeof...(_Args)] = {is_same<_T1, _Args>::value...};
+    static constexpr size_t value = __find_detail::__find_idx(0, __matches);
+    static_assert(value != __not_found, "type not found in type list" );
+    static_assert(value != __ambiguous, "type occurs more than once in type list");
+};
+
+template <class _T1>
+struct __find_exactly_one_checked<_T1> {
+    static_assert(!is_same<_T1, _T1>::value, "type not in empty type list");
+};
+
+} // namespace __find_detail;
+
+template <typename _T1, typename... _Args>
+struct __find_exactly_one_t
+    : public __find_detail::__find_exactly_one_checked<_T1, _Args...> {
+};
+
+template <class _T1, class... _Args>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1& get(tuple<_Args...>& __tup) noexcept
+{
+    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
+}
+
+template <class _T1, class... _Args>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 const& get(tuple<_Args...> const& __tup) noexcept
+{
+    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
+}
+
+template <class _T1, class... _Args>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1&& get(tuple<_Args...>&& __tup) noexcept
+{
+    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
+}
+
+template <class _T1, class... _Args>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _T1 const&& get(tuple<_Args...> const&& __tup) noexcept
+{
+    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
+}
+
+#endif
+
+// tie
+
+template <class ..._Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+tuple<_Tp&...>
+tie(_Tp&... __t) _NOEXCEPT
+{
+    return tuple<_Tp&...>(__t...);
+}
+
+template <class _Up>
+struct __ignore_t
+{
+    template <class _Tp>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    const __ignore_t& operator=(_Tp&&) const {return *this;}
+};
+
+namespace {
+  constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
+}
+
+template <class... _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+tuple<typename __unwrap_ref_decay<_Tp>::type...>
+make_tuple(_Tp&&... __t)
+{
+    return tuple<typename __unwrap_ref_decay<_Tp>::type...>(_VSTD::forward<_Tp>(__t)...);
+}
+
+template <class... _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+tuple<_Tp&&...>
+forward_as_tuple(_Tp&&... __t) _NOEXCEPT
+{
+    return tuple<_Tp&&...>(_VSTD::forward<_Tp>(__t)...);
+}
+
+template <size_t _Ip>
+struct __tuple_equal
+{
+    template <class _Tp, class _Up>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _Tp& __x, const _Up& __y)
+    {
+        return __tuple_equal<_Ip - 1>()(__x, __y) && _VSTD::get<_Ip-1>(__x) == _VSTD::get<_Ip-1>(__y);
+    }
+};
+
+template <>
+struct __tuple_equal<0>
+{
+    template <class _Tp, class _Up>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _Tp&, const _Up&)
+    {
+        return true;
+    }
+};
+
+template <class ..._Tp, class ..._Up>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator==(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
+{
+    static_assert (sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
+    return __tuple_equal<sizeof...(_Tp)>()(__x, __y);
+}
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR) && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// operator<=>
+
+template <class ..._Tp, class ..._Up, size_t ..._Is>
+_LIBCPP_HIDE_FROM_ABI constexpr
+auto
+__tuple_compare_three_way(const tuple<_Tp...>& __x, const tuple<_Up...>& __y, index_sequence<_Is...>) {
+    common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...> __result = strong_ordering::equal;
+    static_cast<void>(((__result = _VSTD::__synth_three_way(_VSTD::get<_Is>(__x), _VSTD::get<_Is>(__y)), __result != 0) || ...));
+    return __result;
+}
+
+template <class ..._Tp, class ..._Up>
+requires (sizeof...(_Tp) == sizeof...(_Up))
+_LIBCPP_HIDE_FROM_ABI constexpr
+common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...>
+operator<=>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
+{
+    return _VSTD::__tuple_compare_three_way(__x, __y, index_sequence_for<_Tp...>{});
+}
+
+#else // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR) && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+template <class ..._Tp, class ..._Up>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator!=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
+{
+    return !(__x == __y);
+}
+
+template <size_t _Ip>
+struct __tuple_less
+{
+    template <class _Tp, class _Up>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _Tp& __x, const _Up& __y)
+    {
+        const size_t __idx = tuple_size<_Tp>::value - _Ip;
+        if (_VSTD::get<__idx>(__x) < _VSTD::get<__idx>(__y))
+            return true;
+        if (_VSTD::get<__idx>(__y) < _VSTD::get<__idx>(__x))
+            return false;
+        return __tuple_less<_Ip-1>()(__x, __y);
+    }
+};
+
+template <>
+struct __tuple_less<0>
+{
+    template <class _Tp, class _Up>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    bool operator()(const _Tp&, const _Up&)
+    {
+        return false;
+    }
+};
+
+template <class ..._Tp, class ..._Up>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator<(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
+{
+    static_assert (sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
+    return __tuple_less<sizeof...(_Tp)>()(__x, __y);
+}
+
+template <class ..._Tp, class ..._Up>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
+{
+    return __y < __x;
+}
+
+template <class ..._Tp, class ..._Up>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator>=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class ..._Tp, class ..._Up>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+bool
+operator<=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
+{
+    return !(__y < __x);
+}
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_SPACESHIP_OPERATOR) && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// tuple_cat
+
+template <class _Tp, class _Up> struct __tuple_cat_type;
+
+template <class ..._Ttypes, class ..._Utypes>
+struct __tuple_cat_type<tuple<_Ttypes...>, __tuple_types<_Utypes...> >
+{
+    typedef _LIBCPP_NODEBUG tuple<_Ttypes..., _Utypes...> type;
+};
+
+template <class _ResultTuple, bool _Is_Tuple0TupleLike, class ..._Tuples>
+struct __tuple_cat_return_1
+{
+};
+
+template <class ..._Types, class _Tuple0>
+struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0>
+{
+    typedef _LIBCPP_NODEBUG typename __tuple_cat_type<tuple<_Types...>,
+            typename __make_tuple_types<typename __uncvref<_Tuple0>::type>::type>::type
+                                                                           type;
+};
+
+template <class ..._Types, class _Tuple0, class _Tuple1, class ..._Tuples>
+struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0, _Tuple1, _Tuples...>
+    : public __tuple_cat_return_1<
+                 typename __tuple_cat_type<
+                     tuple<_Types...>,
+                     typename __make_tuple_types<typename __uncvref<_Tuple0>::type>::type
+                 >::type,
+                 __tuple_like<typename remove_reference<_Tuple1>::type>::value,
+                 _Tuple1, _Tuples...>
+{
+};
+
+template <class ..._Tuples> struct __tuple_cat_return;
+
+template <class _Tuple0, class ..._Tuples>
+struct __tuple_cat_return<_Tuple0, _Tuples...>
+    : public __tuple_cat_return_1<tuple<>,
+         __tuple_like<typename remove_reference<_Tuple0>::type>::value, _Tuple0,
+                                                                     _Tuples...>
+{
+};
+
+template <>
+struct __tuple_cat_return<>
+{
+    typedef _LIBCPP_NODEBUG tuple<> type;
+};
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+tuple<>
+tuple_cat()
+{
+    return tuple<>();
+}
+
+template <class _Rp, class _Indices, class _Tuple0, class ..._Tuples>
+struct __tuple_cat_return_ref_imp;
+
+template <class ..._Types, size_t ..._I0, class _Tuple0>
+struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0>
+{
+    typedef _LIBCPP_NODEBUG typename remove_reference<_Tuple0>::type _T0;
+    typedef tuple<_Types..., typename __apply_cv<_Tuple0,
+                          typename tuple_element<_I0, _T0>::type>::type&&...> type;
+};
+
+template <class ..._Types, size_t ..._I0, class _Tuple0, class _Tuple1, class ..._Tuples>
+struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>,
+                                  _Tuple0, _Tuple1, _Tuples...>
+    : public __tuple_cat_return_ref_imp<
+         tuple<_Types..., typename __apply_cv<_Tuple0,
+               typename tuple_element<_I0,
+                  typename remove_reference<_Tuple0>::type>::type>::type&&...>,
+         typename __make_tuple_indices<tuple_size<typename
+                                 remove_reference<_Tuple1>::type>::value>::type,
+         _Tuple1, _Tuples...>
+{
+};
+
+template <class _Tuple0, class ..._Tuples>
+struct __tuple_cat_return_ref
+    : public __tuple_cat_return_ref_imp<tuple<>,
+               typename __make_tuple_indices<
+                        tuple_size<typename remove_reference<_Tuple0>::type>::value
+               >::type, _Tuple0, _Tuples...>
+{
+};
+
+template <class _Types, class _I0, class _J0>
+struct __tuple_cat;
+
+template <class ..._Types, size_t ..._I0, size_t ..._J0>
+struct __tuple_cat<tuple<_Types...>, __tuple_indices<_I0...>, __tuple_indices<_J0...> >
+{
+    template <class _Tuple0>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&>::type
+    operator()(tuple<_Types...> __t, _Tuple0&& __t0)
+    {
+        return _VSTD::forward_as_tuple(
+            _VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
+            _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...);
+    }
+
+    template <class _Tuple0, class _Tuple1, class ..._Tuples>
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&, _Tuple1&&, _Tuples&&...>::type
+    operator()(tuple<_Types...> __t, _Tuple0&& __t0, _Tuple1&& __t1, _Tuples&& ...__tpls)
+    {
+        typedef _LIBCPP_NODEBUG typename remove_reference<_Tuple0>::type _T0;
+        typedef _LIBCPP_NODEBUG typename remove_reference<_Tuple1>::type _T1;
+        return __tuple_cat<
+            tuple<_Types...,
+                  typename __apply_cv<_Tuple0, typename tuple_element<
+                                                   _J0, _T0>::type>::type&&...>,
+            typename __make_tuple_indices<sizeof...(_Types) +
+                                          tuple_size<_T0>::value>::type,
+            typename __make_tuple_indices<tuple_size<_T1>::value>::type>()(
+            _VSTD::forward_as_tuple(
+                _VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
+                _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...),
+            _VSTD::forward<_Tuple1>(__t1), _VSTD::forward<_Tuples>(__tpls)...);
+    }
+};
+
+template <class _Tuple0, class... _Tuples>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
+typename __tuple_cat_return<_Tuple0, _Tuples...>::type
+tuple_cat(_Tuple0&& __t0, _Tuples&&... __tpls)
+{
+    typedef _LIBCPP_NODEBUG typename remove_reference<_Tuple0>::type _T0;
+    return __tuple_cat<tuple<>, __tuple_indices<>,
+                  typename __make_tuple_indices<tuple_size<_T0>::value>::type>()
+                  (tuple<>(), _VSTD::forward<_Tuple0>(__t0),
+                                            _VSTD::forward<_Tuples>(__tpls)...);
+}
+
+template <class ..._Tp, class _Alloc>
+struct _LIBCPP_TEMPLATE_VIS uses_allocator<tuple<_Tp...>, _Alloc>
+    : true_type {};
+
+template <class _T1, class _T2>
+template <class... _Args1, class... _Args2, size_t ..._I1, size_t ..._I2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+pair<_T1, _T2>::pair(piecewise_construct_t,
+                     tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
+                     __tuple_indices<_I1...>, __tuple_indices<_I2...>)
+    :  first(_VSTD::forward<_Args1>(_VSTD::get<_I1>( __first_args))...),
+      second(_VSTD::forward<_Args2>(_VSTD::get<_I2>(__second_args))...)
+{
+    (void)__first_args;
+    (void)__second_args;
+}
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
+
+#define _LIBCPP_NOEXCEPT_RETURN(...) noexcept(noexcept(__VA_ARGS__)) { return __VA_ARGS__; }
+
+template <class _Fn, class _Tuple, size_t ..._Id>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr decltype(auto) __apply_tuple_impl(_Fn && __f, _Tuple && __t,
+                                            __tuple_indices<_Id...>)
+_LIBCPP_NOEXCEPT_RETURN(
+    _VSTD::__invoke_constexpr(
+        _VSTD::forward<_Fn>(__f),
+        _VSTD::get<_Id>(_VSTD::forward<_Tuple>(__t))...)
+)
+
+template <class _Fn, class _Tuple>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr decltype(auto) apply(_Fn && __f, _Tuple && __t)
+_LIBCPP_NOEXCEPT_RETURN(
+    _VSTD::__apply_tuple_impl(
+        _VSTD::forward<_Fn>(__f), _VSTD::forward<_Tuple>(__t),
+        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{})
+)
+
+template <class _Tp, class _Tuple, size_t... _Idx>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _Tp __make_from_tuple_impl(_Tuple&& __t, __tuple_indices<_Idx...>)
+_LIBCPP_NOEXCEPT_RETURN(
+    _Tp(_VSTD::get<_Idx>(_VSTD::forward<_Tuple>(__t))...)
+)
+
+template <class _Tp, class _Tuple>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _Tp make_from_tuple(_Tuple&& __t)
+_LIBCPP_NOEXCEPT_RETURN(
+    _VSTD::__make_from_tuple_impl<_Tp>(_VSTD::forward<_Tuple>(__t),
+        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{})
+)
+
+#undef _LIBCPP_NOEXCEPT_RETURN
+
+#endif // _LIBCPP_STD_VER > 14
+
+#endif // !defined(_LIBCPP_CXX03_LANG)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_TUPLE
diff --git a/contrib/libs/cxxsupp/libcxx/include/type_traits b/contrib/libs/cxxsupp/libcxx/include/type_traits
new file mode 100644
index 00000000000..8c915220746
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/type_traits
@@ -0,0 +1,4241 @@
+// -*- C++ -*-
+//===------------------------ type_traits ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_TYPE_TRAITS
+#define _LIBCPP_TYPE_TRAITS
+
+/*
+    type_traits synopsis
+
+namespace std
+{
+
+    // helper class:
+    template <class T, T v> struct integral_constant;
+    typedef integral_constant<bool, true>  true_type;   // C++11
+    typedef integral_constant<bool, false> false_type;  // C++11
+
+    template <bool B>                                   // C++14
+    using bool_constant = integral_constant<bool, B>;   // C++14
+    typedef bool_constant<true> true_type;              // C++14
+    typedef bool_constant<false> false_type;            // C++14
+
+    // helper traits
+    template <bool, class T = void> struct enable_if;
+    template <bool, class T, class F> struct conditional;
+
+    // Primary classification traits:
+    template <class T> struct is_void;
+    template <class T> struct is_null_pointer;  // C++14
+    template <class T> struct is_integral;
+    template <class T> struct is_floating_point;
+    template <class T> struct is_array;
+    template <class T> struct is_pointer;
+    template <class T> struct is_lvalue_reference;
+    template <class T> struct is_rvalue_reference;
+    template <class T> struct is_member_object_pointer;
+    template <class T> struct is_member_function_pointer;
+    template <class T> struct is_enum;
+    template <class T> struct is_union;
+    template <class T> struct is_class;
+    template <class T> struct is_function;
+
+    // Secondary classification traits:
+    template <class T> struct is_reference;
+    template <class T> struct is_arithmetic;
+    template <class T> struct is_fundamental;
+    template <class T> struct is_member_pointer;
+    template <class T> struct is_scoped_enum; // C++2b
+    template <class T> struct is_scalar;
+    template <class T> struct is_object;
+    template <class T> struct is_compound;
+
+    // Const-volatile properties and transformations:
+    template <class T> struct is_const;
+    template <class T> struct is_volatile;
+    template <class T> struct remove_const;
+    template <class T> struct remove_volatile;
+    template <class T> struct remove_cv;
+    template <class T> struct add_const;
+    template <class T> struct add_volatile;
+    template <class T> struct add_cv;
+
+    // Reference transformations:
+    template <class T> struct remove_reference;
+    template <class T> struct add_lvalue_reference;
+    template <class T> struct add_rvalue_reference;
+
+    // Pointer transformations:
+    template <class T> struct remove_pointer;
+    template <class T> struct add_pointer;
+
+    template<class T> struct type_identity;                     // C++20
+    template<class T>
+      using type_identity_t = typename type_identity<T>::type;  // C++20
+
+    // Integral properties:
+    template <class T> struct is_signed;
+    template <class T> struct is_unsigned;
+    template <class T> struct make_signed;
+    template <class T> struct make_unsigned;
+
+    // Array properties and transformations:
+    template <class T> struct rank;
+    template <class T, unsigned I = 0> struct extent;
+    template <class T> struct remove_extent;
+    template <class T> struct remove_all_extents;
+
+    template <class T> struct is_bounded_array;                 // C++20
+    template <class T> struct is_unbounded_array;               // C++20
+
+    // Member introspection:
+    template <class T> struct is_pod;
+    template <class T> struct is_trivial;
+    template <class T> struct is_trivially_copyable;
+    template <class T> struct is_standard_layout;
+    template <class T> struct is_literal_type; // Deprecated in C++17; removed in C++20
+    template <class T> struct is_empty;
+    template <class T> struct is_polymorphic;
+    template <class T> struct is_abstract;
+    template <class T> struct is_final; // C++14
+    template <class T> struct is_aggregate; // C++17
+
+    template <class T, class... Args> struct is_constructible;
+    template <class T>                struct is_default_constructible;
+    template <class T>                struct is_copy_constructible;
+    template <class T>                struct is_move_constructible;
+    template <class T, class U>       struct is_assignable;
+    template <class T>                struct is_copy_assignable;
+    template <class T>                struct is_move_assignable;
+    template <class T, class U>       struct is_swappable_with;       // C++17
+    template <class T>                struct is_swappable;            // C++17
+    template <class T>                struct is_destructible;
+
+    template <class T, class... Args> struct is_trivially_constructible;
+    template <class T>                struct is_trivially_default_constructible;
+    template <class T>                struct is_trivially_copy_constructible;
+    template <class T>                struct is_trivially_move_constructible;
+    template <class T, class U>       struct is_trivially_assignable;
+    template <class T>                struct is_trivially_copy_assignable;
+    template <class T>                struct is_trivially_move_assignable;
+    template <class T>                struct is_trivially_destructible;
+
+    template <class T, class... Args> struct is_nothrow_constructible;
+    template <class T>                struct is_nothrow_default_constructible;
+    template <class T>                struct is_nothrow_copy_constructible;
+    template <class T>                struct is_nothrow_move_constructible;
+    template <class T, class U>       struct is_nothrow_assignable;
+    template <class T>                struct is_nothrow_copy_assignable;
+    template <class T>                struct is_nothrow_move_assignable;
+    template <class T, class U>       struct is_nothrow_swappable_with; // C++17
+    template <class T>                struct is_nothrow_swappable;      // C++17
+    template <class T>                struct is_nothrow_destructible;
+
+    template <class T> struct has_virtual_destructor;
+
+    template<class T> struct has_unique_object_representations;         // C++17
+
+    // Relationships between types:
+    template <class T, class U> struct is_same;
+    template <class Base, class Derived> struct is_base_of;
+
+    template <class From, class To> struct is_convertible;
+    template <typename From, typename To> struct is_nothrow_convertible;                  // C++20
+    template <typename From, typename To> inline constexpr bool is_nothrow_convertible_v; // C++20
+
+    template <class Fn, class... ArgTypes> struct is_invocable;
+    template <class R, class Fn, class... ArgTypes> struct is_invocable_r;
+
+    template <class Fn, class... ArgTypes> struct is_nothrow_invocable;
+    template <class R, class Fn, class... ArgTypes> struct is_nothrow_invocable_r;
+
+    // Alignment properties and transformations:
+    template <class T> struct alignment_of;
+    template <size_t Len, size_t Align = most_stringent_alignment_requirement>
+        struct aligned_storage;
+    template <size_t Len, class... Types> struct aligned_union;
+    template <class T> struct remove_cvref; // C++20
+
+    template <class T> struct decay;
+    template <class... T> struct common_type;
+    template <class T> struct underlying_type;
+    template <class> class result_of; // undefined; deprecated in C++17; removed in C++20
+    template <class Fn, class... ArgTypes> class result_of<Fn(ArgTypes...)>; // deprecated in C++17; removed in C++20
+    template <class Fn, class... ArgTypes> struct invoke_result;  // C++17
+
+    // const-volatile modifications:
+    template <class T>
+      using remove_const_t    = typename remove_const<T>::type;  // C++14
+    template <class T>
+      using remove_volatile_t = typename remove_volatile<T>::type;  // C++14
+    template <class T>
+      using remove_cv_t       = typename remove_cv<T>::type;  // C++14
+    template <class T>
+      using add_const_t       = typename add_const<T>::type;  // C++14
+    template <class T>
+      using add_volatile_t    = typename add_volatile<T>::type;  // C++14
+    template <class T>
+      using add_cv_t          = typename add_cv<T>::type;  // C++14
+
+    // reference modifications:
+    template <class T>
+      using remove_reference_t     = typename remove_reference<T>::type;  // C++14
+    template <class T>
+      using add_lvalue_reference_t = typename add_lvalue_reference<T>::type;  // C++14
+    template <class T>
+      using add_rvalue_reference_t = typename add_rvalue_reference<T>::type;  // C++14
+
+    // sign modifications:
+    template <class T>
+      using make_signed_t   = typename make_signed<T>::type;  // C++14
+    template <class T>
+      using make_unsigned_t = typename make_unsigned<T>::type;  // C++14
+
+    // array modifications:
+    template <class T>
+      using remove_extent_t      = typename remove_extent<T>::type;  // C++14
+    template <class T>
+      using remove_all_extents_t = typename remove_all_extents<T>::type;  // C++14
+
+    template <class T>
+      inline constexpr bool is_bounded_array_v
+        = is_bounded_array<T>::value;                                     // C++20
+      inline constexpr bool is_unbounded_array_v
+        = is_unbounded_array<T>::value;                                   // C++20
+
+    // pointer modifications:
+    template <class T>
+      using remove_pointer_t = typename remove_pointer<T>::type;  // C++14
+    template <class T>
+      using add_pointer_t    = typename add_pointer<T>::type;  // C++14
+
+    // other transformations:
+    template <size_t Len, size_t Align=default-alignment>
+      using aligned_storage_t = typename aligned_storage<Len,Align>::type;  // C++14
+    template <size_t Len, class... Types>
+      using aligned_union_t   = typename aligned_union<Len,Types...>::type;  // C++14
+    template <class T>
+      using remove_cvref_t    = typename remove_cvref<T>::type;  // C++20
+    template <class T>
+      using decay_t           = typename decay<T>::type;  // C++14
+    template <bool b, class T=void>
+      using enable_if_t       = typename enable_if<b,T>::type;  // C++14
+    template <bool b, class T, class F>
+      using conditional_t     = typename conditional<b,T,F>::type;  // C++14
+    template <class... T>
+      using common_type_t     = typename common_type<T...>::type;  // C++14
+    template <class T>
+      using underlying_type_t = typename underlying_type<T>::type;  // C++14
+    template <class T>
+      using result_of_t       = typename result_of<T>::type;  // C++14; deprecated in C++17; removed in C++20
+    template <class Fn, class... ArgTypes>
+      using invoke_result_t   = typename invoke_result<Fn, ArgTypes...>::type;  // C++17
+
+    template <class...>
+      using void_t = void;   // C++17
+
+      // See C++14 20.10.4.1, primary type categories
+      template <class T> inline constexpr bool is_void_v
+        = is_void<T>::value;                                             // C++17
+      template <class T> inline constexpr bool is_null_pointer_v
+        = is_null_pointer<T>::value;                                     // C++17
+      template <class T> inline constexpr bool is_integral_v
+        = is_integral<T>::value;                                         // C++17
+      template <class T> inline constexpr bool is_floating_point_v
+        = is_floating_point<T>::value;                                   // C++17
+      template <class T> inline constexpr bool is_array_v
+        = is_array<T>::value;                                            // C++17
+      template <class T> inline constexpr bool is_pointer_v
+        = is_pointer<T>::value;                                          // C++17
+      template <class T> inline constexpr bool is_lvalue_reference_v
+        = is_lvalue_reference<T>::value;                                 // C++17
+      template <class T> inline constexpr bool is_rvalue_reference_v
+        = is_rvalue_reference<T>::value;                                 // C++17
+      template <class T> inline constexpr bool is_member_object_pointer_v
+        = is_member_object_pointer<T>::value;                            // C++17
+      template <class T> inline constexpr bool is_member_function_pointer_v
+        = is_member_function_pointer<T>::value;                          // C++17
+      template <class T> inline constexpr bool is_enum_v
+        = is_enum<T>::value;                                             // C++17
+      template <class T> inline constexpr bool is_union_v
+        = is_union<T>::value;                                            // C++17
+      template <class T> inline constexpr bool is_class_v
+        = is_class<T>::value;                                            // C++17
+      template <class T> inline constexpr bool is_function_v
+        = is_function<T>::value;                                         // C++17
+
+      // See C++14 20.10.4.2, composite type categories
+      template <class T> inline constexpr bool is_reference_v
+        = is_reference<T>::value;                                        // C++17
+      template <class T> inline constexpr bool is_arithmetic_v
+        = is_arithmetic<T>::value;                                       // C++17
+      template <class T> inline constexpr bool is_fundamental_v
+        = is_fundamental<T>::value;                                      // C++17
+      template <class T> inline constexpr bool is_object_v
+        = is_object<T>::value;                                           // C++17
+      template <class T> inline constexpr bool is_scalar_v
+        = is_scalar<T>::value;                                           // C++17
+      template <class T> inline constexpr bool is_compound_v
+        = is_compound<T>::value;                                         // C++17
+      template <class T> inline constexpr bool is_member_pointer_v
+        = is_member_pointer<T>::value;                                   // C++17
+      template <class T> inline constexpr bool is_scoped_enum_v
+        = is_scoped_enum<T>::value;                                      // C++2b
+
+      // See C++14 20.10.4.3, type properties
+      template <class T> inline constexpr bool is_const_v
+        = is_const<T>::value;                                            // C++17
+      template <class T> inline constexpr bool is_volatile_v
+        = is_volatile<T>::value;                                         // C++17
+      template <class T> inline constexpr bool is_trivial_v
+        = is_trivial<T>::value;                                          // C++17
+      template <class T> inline constexpr bool is_trivially_copyable_v
+        = is_trivially_copyable<T>::value;                               // C++17
+      template <class T> inline constexpr bool is_standard_layout_v
+        = is_standard_layout<T>::value;                                  // C++17
+      template <class T> inline constexpr bool is_pod_v
+        = is_pod<T>::value;                                              // C++17
+      template <class T> inline constexpr bool is_literal_type_v
+        = is_literal_type<T>::value;                                     // C++17; deprecated in C++17; removed in C++20
+      template <class T> inline constexpr bool is_empty_v
+        = is_empty<T>::value;                                            // C++17
+      template <class T> inline constexpr bool is_polymorphic_v
+        = is_polymorphic<T>::value;                                      // C++17
+      template <class T> inline constexpr bool is_abstract_v
+        = is_abstract<T>::value;                                         // C++17
+      template <class T> inline constexpr bool is_final_v
+        = is_final<T>::value;                                            // C++17
+      template <class T> inline constexpr bool is_aggregate_v
+        = is_aggregate<T>::value;                                        // C++17
+      template <class T> inline constexpr bool is_signed_v
+        = is_signed<T>::value;                                           // C++17
+      template <class T> inline constexpr bool is_unsigned_v
+        = is_unsigned<T>::value;                                         // C++17
+      template <class T, class... Args> inline constexpr bool is_constructible_v
+        = is_constructible<T, Args...>::value;                           // C++17
+      template <class T> inline constexpr bool is_default_constructible_v
+        = is_default_constructible<T>::value;                            // C++17
+      template <class T> inline constexpr bool is_copy_constructible_v
+        = is_copy_constructible<T>::value;                               // C++17
+      template <class T> inline constexpr bool is_move_constructible_v
+        = is_move_constructible<T>::value;                               // C++17
+      template <class T, class U> inline constexpr bool is_assignable_v
+        = is_assignable<T, U>::value;                                    // C++17
+      template <class T> inline constexpr bool is_copy_assignable_v
+        = is_copy_assignable<T>::value;                                  // C++17
+      template <class T> inline constexpr bool is_move_assignable_v
+        = is_move_assignable<T>::value;                                  // C++17
+      template <class T, class U> inline constexpr bool is_swappable_with_v
+        = is_swappable_with<T, U>::value;                                // C++17
+      template <class T> inline constexpr bool is_swappable_v
+        = is_swappable<T>::value;                                        // C++17
+      template <class T> inline constexpr bool is_destructible_v
+        = is_destructible<T>::value;                                     // C++17
+      template <class T, class... Args> inline constexpr bool is_trivially_constructible_v
+        = is_trivially_constructible<T, Args...>::value;                 // C++17
+      template <class T> inline constexpr bool is_trivially_default_constructible_v
+        = is_trivially_default_constructible<T>::value;                  // C++17
+      template <class T> inline constexpr bool is_trivially_copy_constructible_v
+        = is_trivially_copy_constructible<T>::value;                     // C++17
+      template <class T> inline constexpr bool is_trivially_move_constructible_v
+        = is_trivially_move_constructible<T>::value;                     // C++17
+      template <class T, class U> inline constexpr bool is_trivially_assignable_v
+        = is_trivially_assignable<T, U>::value;                          // C++17
+      template <class T> inline constexpr bool is_trivially_copy_assignable_v
+        = is_trivially_copy_assignable<T>::value;                        // C++17
+      template <class T> inline constexpr bool is_trivially_move_assignable_v
+        = is_trivially_move_assignable<T>::value;                        // C++17
+      template <class T> inline constexpr bool is_trivially_destructible_v
+        = is_trivially_destructible<T>::value;                           // C++17
+      template <class T, class... Args> inline constexpr bool is_nothrow_constructible_v
+        = is_nothrow_constructible<T, Args...>::value;                   // C++17
+      template <class T> inline constexpr bool is_nothrow_default_constructible_v
+        = is_nothrow_default_constructible<T>::value;                    // C++17
+      template <class T> inline constexpr bool is_nothrow_copy_constructible_v
+        = is_nothrow_copy_constructible<T>::value;                       // C++17
+      template <class T> inline constexpr bool is_nothrow_move_constructible_v
+        = is_nothrow_move_constructible<T>::value;                       // C++17
+      template <class T, class U> inline constexpr bool is_nothrow_assignable_v
+        = is_nothrow_assignable<T, U>::value;                            // C++17
+      template <class T> inline constexpr bool is_nothrow_copy_assignable_v
+        = is_nothrow_copy_assignable<T>::value;                          // C++17
+      template <class T> inline constexpr bool is_nothrow_move_assignable_v
+        = is_nothrow_move_assignable<T>::value;                          // C++17
+      template <class T, class U> inline constexpr bool is_nothrow_swappable_with_v
+        = is_nothrow_swappable_with<T, U>::value;                       // C++17
+      template <class T> inline constexpr bool is_nothrow_swappable_v
+        = is_nothrow_swappable<T>::value;                               // C++17
+      template <class T> inline constexpr bool is_nothrow_destructible_v
+        = is_nothrow_destructible<T>::value;                             // C++17
+      template <class T> inline constexpr bool has_virtual_destructor_v
+        = has_virtual_destructor<T>::value;                              // C++17
+      template<class T> inline constexpr bool has_unique_object_representations_v // C++17
+        = has_unique_object_representations<T>::value;
+
+      // See C++14 20.10.5, type property queries
+      template <class T> inline constexpr size_t alignment_of_v
+        = alignment_of<T>::value;                                        // C++17
+      template <class T> inline constexpr size_t rank_v
+        = rank<T>::value;                                                // C++17
+      template <class T, unsigned I = 0> inline constexpr size_t extent_v
+        = extent<T, I>::value;                                           // C++17
+
+      // See C++14 20.10.6, type relations
+      template <class T, class U> inline constexpr bool is_same_v
+        = is_same<T, U>::value;                                          // C++17
+      template <class Base, class Derived> inline constexpr bool is_base_of_v
+        = is_base_of<Base, Derived>::value;                              // C++17
+      template <class From, class To> inline constexpr bool is_convertible_v
+        = is_convertible<From, To>::value;                               // C++17
+      template <class Fn, class... ArgTypes> inline constexpr bool is_invocable_v
+        = is_invocable<Fn, ArgTypes...>::value;                          // C++17
+      template <class R, class Fn, class... ArgTypes> inline constexpr bool is_invocable_r_v
+        = is_invocable_r<R, Fn, ArgTypes...>::value;                     // C++17
+      template <class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_v
+        = is_nothrow_invocable<Fn, ArgTypes...>::value;                  // C++17
+      template <class R, class Fn, class... ArgTypes> inline constexpr bool is_nothrow_invocable_r_v
+        = is_nothrow_invocable_r<R, Fn, ArgTypes...>::value;             // C++17
+
+      // [meta.logical], logical operator traits:
+      template<class... B> struct conjunction;                           // C++17
+      template<class... B>
+        inline constexpr bool conjunction_v = conjunction<B...>::value;  // C++17
+      template<class... B> struct disjunction;                           // C++17
+      template<class... B>
+        inline constexpr bool disjunction_v = disjunction<B...>::value;  // C++17
+      template<class B> struct negation;                                 // C++17
+      template<class B>
+        inline constexpr bool negation_v = negation<B>::value;           // C++17
+
+}
+
+*/
+#include <__config>
+#include <cstddef>
+#include <version>
+#include <__utility/declval.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning(push)
+#pragma warning(disable: 4296)
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS pair;
+template <class _Tp> class _LIBCPP_TEMPLATE_VIS reference_wrapper;
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS hash;
+
+template <class _Tp, _Tp __v>
+struct _LIBCPP_TEMPLATE_VIS integral_constant
+{
+  static _LIBCPP_CONSTEXPR const _Tp      value = __v;
+  typedef _Tp               value_type;
+  typedef integral_constant type;
+  _LIBCPP_INLINE_VISIBILITY
+  _LIBCPP_CONSTEXPR operator value_type() const _NOEXCEPT {return value;}
+#if _LIBCPP_STD_VER > 11
+  _LIBCPP_INLINE_VISIBILITY
+  constexpr value_type operator ()() const _NOEXCEPT {return value;}
+#endif
+};
+
+template <class _Tp, _Tp __v>
+_LIBCPP_CONSTEXPR const _Tp integral_constant<_Tp, __v>::value;
+
+#if _LIBCPP_STD_VER > 14
+template <bool __b>
+using bool_constant = integral_constant<bool, __b>;
+#define _LIBCPP_BOOL_CONSTANT(__b) bool_constant<(__b)>
+#else
+#define _LIBCPP_BOOL_CONSTANT(__b) integral_constant<bool,(__b)>
+#endif
+
+template <bool, class _Tp = void> struct _LIBCPP_TEMPLATE_VIS enable_if {};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS enable_if<true, _Tp> {typedef _Tp type;};
+
+template <bool _Bp, class _Tp = void> using __enable_if_t _LIBCPP_NODEBUG = typename enable_if<_Bp, _Tp>::type;
+
+#if _LIBCPP_STD_VER > 11
+template <bool _Bp, class _Tp = void> using enable_if_t = typename enable_if<_Bp, _Tp>::type;
+#endif
+
+typedef _LIBCPP_BOOL_CONSTANT(true)  true_type;
+typedef _LIBCPP_BOOL_CONSTANT(false) false_type;
+
+template <bool _Val>
+using _BoolConstant _LIBCPP_NODEBUG = integral_constant<bool, _Val>;
+
+template <bool> struct _MetaBase;
+template <>
+struct _MetaBase<true> {
+  template <class _Tp, class _Up>
+  using _SelectImpl _LIBCPP_NODEBUG = _Tp;
+  template <template <class...> class _FirstFn, template <class...> class, class ..._Args>
+  using _SelectApplyImpl _LIBCPP_NODEBUG = _FirstFn<_Args...>;
+  template <class _First, class...>
+  using _FirstImpl _LIBCPP_NODEBUG = _First;
+  template <class, class _Second, class...>
+  using _SecondImpl _LIBCPP_NODEBUG = _Second;
+  template <class _Result, class _First, class ..._Rest>
+  using _OrImpl _LIBCPP_NODEBUG = typename _MetaBase<_First::value != true && sizeof...(_Rest) != 0>::template _OrImpl<_First, _Rest...>;
+  template <class _Result, class _First, class ..._Rest>
+  using _AndImpl _LIBCPP_NODEBUG = typename _MetaBase<_First::value == true && sizeof...(_Rest) != 0>::template _AndImpl<_First, _Rest...>;
+};
+
+template <>
+struct _MetaBase<false> {
+  template <class _Tp, class _Up>
+  using _SelectImpl _LIBCPP_NODEBUG = _Up;
+  template <template <class...> class, template <class...> class _SecondFn, class ..._Args>
+  using _SelectApplyImpl _LIBCPP_NODEBUG = _SecondFn<_Args...>;
+  template <class _Result, class ...>
+  using _OrImpl _LIBCPP_NODEBUG = _Result;
+  template <class _Result, class ...>
+  using _AndImpl _LIBCPP_NODEBUG = _Result;
+};
+// Workaround for MSVC. Sometimes compiler thinks that sizeof...(Type) is parameter pack rather than the number.
+// So it doesn't allow sizeof...(Type) in expression that goes into the boolean template parameter of _MetaBase.
+// This simple wrapper allows us to hide sizeof... from the compiler.
+template<class... _Pack>
+struct _Sizeof {
+    static constexpr size_t value = sizeof...(_Pack);
+};
+// CUDA headers use libc++ internals.
+#ifdef __CUDACC__
+template <bool _Cond, class _Ret = void>
+using __lazy_enable_if _LIBCPP_NODEBUG = __enable_if_t<_Cond, _Ret>;
+#endif
+template <bool _Cond, class _IfRes, class _ElseRes>
+using _If _LIBCPP_NODEBUG = typename _MetaBase<_Cond>::template _SelectImpl<_IfRes, _ElseRes>;
+template <class ..._Rest>
+using _Or _LIBCPP_NODEBUG = typename _MetaBase< _Sizeof<_Rest...>::value != 0 >::template _OrImpl<false_type, _Rest...>;
+template <class _Pred>
+struct _Not : _BoolConstant<!_Pred::value> {};
+template <class ..._Args>
+using _FirstType _LIBCPP_NODEBUG = typename _MetaBase<(_Sizeof<_Args...>::value >= 1)>::template _FirstImpl<_Args...>;
+template <class ..._Args>
+using _SecondType _LIBCPP_NODEBUG = typename _MetaBase<(_Sizeof<_Args...>::value >= 2)>::template _SecondImpl<_Args...>;
+
+// fold-based implementation fails on multiple compilers.
+#if 1
+template <class ..._Rest>
+using _And _LIBCPP_NODEBUG = typename _MetaBase< _Sizeof<_Rest...>::value != 0 >::template _AndImpl<true_type, _Rest...>;
+#else
+template <class ...> using __expand_to_true = true_type;
+template <class ..._Pred>
+__expand_to_true<__enable_if_t<std::bool_constant<_Pred::value>::value>...> __and_helper(int);
+template <class ...>
+false_type __and_helper(...);
+template <class ..._Pred>
+using _And _LIBCPP_NODEBUG = decltype(__and_helper<std::bool_constant<_Pred::value>...>(0));
+#endif
+
+template <template <class...> class _Func, class ..._Args>
+struct _Lazy : _Func<_Args...> {};
+
+// Member detector base
+
+template <template <class...> class _Templ, class ..._Args, class = _Templ<_Args...> >
+true_type __sfinae_test_impl(int);
+template <template <class...> class, class ...>
+false_type __sfinae_test_impl(...);
+
+template <template <class ...> class _Templ, class ..._Args>
+using _IsValidExpansion _LIBCPP_NODEBUG = decltype(__sfinae_test_impl<_Templ, _Args...>(0));
+
+template <class>
+struct __void_t { typedef void type; };
+
+template <class _Tp>
+struct __identity { typedef _Tp type; };
+
+template <class _Tp>
+using __identity_t _LIBCPP_NODEBUG = typename __identity<_Tp>::type;
+
+template <class _Tp, bool>
+struct _LIBCPP_TEMPLATE_VIS __dependent_type : public _Tp {};
+
+
+template <bool _Bp, class _If, class _Then>
+    struct _LIBCPP_TEMPLATE_VIS conditional {typedef _If type;};
+template <class _If, class _Then>
+    struct _LIBCPP_TEMPLATE_VIS conditional<false, _If, _Then> {typedef _Then type;};
+
+#if _LIBCPP_STD_VER > 11
+template <bool _Bp, class _If, class _Then> using conditional_t = typename conditional<_Bp, _If, _Then>::type;
+#endif
+
+// is_same
+
+#if __has_keyword(__is_same) && !defined(__CUDACC__)
+
+template <class _Tp, class _Up>
+struct _LIBCPP_TEMPLATE_VIS is_same : _BoolConstant<__is_same(_Tp, _Up)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, class _Up>
+inline constexpr bool is_same_v = __is_same(_Tp, _Up);
+#endif
+
+#else
+
+template <class _Tp, class _Up> struct _LIBCPP_TEMPLATE_VIS is_same           : public false_type {};
+template <class _Tp>            struct _LIBCPP_TEMPLATE_VIS is_same<_Tp, _Tp> : public true_type {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, class _Up>
+inline constexpr bool is_same_v = is_same<_Tp, _Up>::value;
+#endif
+
+#endif // __is_same
+
+template <class _Tp, class _Up>
+using _IsSame = _BoolConstant<
+#if defined(__clang__) && !defined(__CUDACC__)
+    __is_same(_Tp, _Up)
+#else
+    is_same<_Tp, _Up>::value
+#endif
+>;
+
+template <class _Tp, class _Up>
+using _IsNotSame = _BoolConstant<
+#if defined(__clang__) && !defined(__CUDACC__)
+    !__is_same(_Tp, _Up)
+#else
+    !is_same<_Tp, _Up>::value
+#endif
+>;
+
+
+template <class _Tp>
+using __test_for_primary_template = __enable_if_t<
+    _IsSame<_Tp, typename _Tp::__primary_template>::value
+  >;
+template <class _Tp>
+using __is_primary_template = _IsValidExpansion<
+    __test_for_primary_template, _Tp
+  >;
+
+struct __two {char __lx[2];};
+
+// helper class:
+
+// is_const
+
+#if __has_keyword(__is_const) && !defined(__CUDACC__)
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_const : _BoolConstant<__is_const(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_const_v = __is_const(_Tp);
+#endif
+
+#else
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_const            : public false_type {};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_const<_Tp const> : public true_type {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_const_v = is_const<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_const)
+
+// is_volatile
+
+#if __has_keyword(__is_volatile) && !defined(__CUDACC__)
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_volatile : _BoolConstant<__is_volatile(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_volatile_v = __is_volatile(_Tp);
+#endif
+
+#else
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_volatile               : public false_type {};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_volatile<_Tp volatile> : public true_type {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_volatile_v = is_volatile<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_volatile)
+
+// remove_const
+
+#if __has_keyword(__remove_const)
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS remove_const {typedef __remove_const(_Tp) type;};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using remove_const_t = __remove_const(_Tp);
+#endif
+
+#else
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_const            {typedef _Tp type;};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_const<const _Tp> {typedef _Tp type;};
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using remove_const_t = typename remove_const<_Tp>::type;
+#endif
+
+#endif // __has_keyword(__remove_const)
+
+// remove_volatile
+
+#if __has_keyword(__remove_volatile)
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS remove_volatile {typedef __remove_volatile(_Tp) type;};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using remove_volatile_t = __remove_volatile(_Tp);
+#endif
+
+#else
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_volatile               {typedef _Tp type;};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_volatile<volatile _Tp> {typedef _Tp type;};
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using remove_volatile_t = typename remove_volatile<_Tp>::type;
+#endif
+
+#endif // __has_keyword(__remove_volatile)
+
+// remove_cv
+
+#if __has_keyword(__remove_cv)
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS remove_cv {typedef __remove_cv(_Tp) type;};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using remove_cv_t = __remove_cv(_Tp);
+#endif
+
+#else
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_cv
+{typedef typename remove_volatile<typename remove_const<_Tp>::type>::type type;};
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using remove_cv_t = typename remove_cv<_Tp>::type;
+#endif
+
+#endif // __has_keyword(__remove_cv)
+
+// is_void
+
+#if __has_keyword(__is_void) && !defined(__CUDACC__)
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_void : _BoolConstant<__is_void(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_void_v = __is_void(_Tp);
+#endif
+
+#else
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_void
+    : public is_same<typename remove_cv<_Tp>::type, void> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_void_v = is_void<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_void)
+
+// __is_nullptr_t
+
+template <class _Tp> struct __is_nullptr_t_impl       : public false_type {};
+template <>          struct __is_nullptr_t_impl<nullptr_t> : public true_type {};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS __is_nullptr_t
+    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_null_pointer
+    : public __is_nullptr_t_impl<typename remove_cv<_Tp>::type> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_null_pointer_v = is_null_pointer<_Tp>::value;
+#endif
+#endif // _LIBCPP_STD_VER > 11
+
+// is_integral
+
+#if __has_keyword(__is_integral) && !defined(__CUDACC__)
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_integral : _BoolConstant<__is_integral(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_integral_v = __is_integral(_Tp);
+#endif
+
+#else
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_integral
+    : public _BoolConstant<__libcpp_is_integral<typename remove_cv<_Tp>::type>::value> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_integral_v = is_integral<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_integral)
+
+// [basic.fundamental] defines five standard signed integer types;
+// __int128_t is an extended signed integer type.
+// The signed and unsigned integer types, plus bool and the
+// five types with "char" in their name, compose the "integral" types.
+
+template <class _Tp> struct __libcpp_is_signed_integer : public false_type {};
+template <> struct __libcpp_is_signed_integer<signed char>      : public true_type {};
+template <> struct __libcpp_is_signed_integer<signed short>     : public true_type {};
+template <> struct __libcpp_is_signed_integer<signed int>       : public true_type {};
+template <> struct __libcpp_is_signed_integer<signed long>      : public true_type {};
+template <> struct __libcpp_is_signed_integer<signed long long> : public true_type {};
+#ifndef _LIBCPP_HAS_NO_INT128
+template <> struct __libcpp_is_signed_integer<__int128_t>       : public true_type {};
+#endif
+
+template <class _Tp> struct __libcpp_is_unsigned_integer : public false_type {};
+template <> struct __libcpp_is_unsigned_integer<unsigned char>      : public true_type {};
+template <> struct __libcpp_is_unsigned_integer<unsigned short>     : public true_type {};
+template <> struct __libcpp_is_unsigned_integer<unsigned int>       : public true_type {};
+template <> struct __libcpp_is_unsigned_integer<unsigned long>      : public true_type {};
+template <> struct __libcpp_is_unsigned_integer<unsigned long long> : public true_type {};
+#ifndef _LIBCPP_HAS_NO_INT128
+template <> struct __libcpp_is_unsigned_integer<__uint128_t>        : public true_type {};
+#endif
+
+// is_floating_point
+// <concepts> implements __libcpp_floating_point
+
+template <class _Tp> struct __libcpp_is_floating_point              : public false_type {};
+template <>          struct __libcpp_is_floating_point<float>       : public true_type {};
+template <>          struct __libcpp_is_floating_point<double>      : public true_type {};
+template <>          struct __libcpp_is_floating_point<long double> : public true_type {};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_floating_point
+    : public __libcpp_is_floating_point<typename remove_cv<_Tp>::type> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_floating_point_v = is_floating_point<_Tp>::value;
+#endif
+
+// is_array
+
+#if __has_keyword(__is_array) && !defined(__CUDACC__)
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_array : _BoolConstant<__is_array(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_array_v = __is_array(_Tp);
+#endif
+
+#else
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_array
+    : public false_type {};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[]>
+    : public true_type {};
+template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_array<_Tp[_Np]>
+    : public true_type {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_array_v = is_array<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_array)
+
+// is_pointer
+
+// Before Clang 11 / AppleClang 12.0.5, __is_pointer didn't work for Objective-C types.
+#if __has_keyword(__is_pointer) &&                                             \
+    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1100) &&               \
+    !(defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1205) &&   \
+    !defined(__CUDACC__)
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_pointer : _BoolConstant<__is_pointer(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_pointer_v = __is_pointer(_Tp);
+#endif
+
+#else // __has_keyword(__is_pointer)
+
+template <class _Tp> struct __libcpp_is_pointer       : public false_type {};
+template <class _Tp> struct __libcpp_is_pointer<_Tp*> : public true_type {};
+
+template <class _Tp> struct __libcpp_remove_objc_qualifiers { typedef _Tp type; };
+#if defined(_LIBCPP_HAS_OBJC_ARC)
+template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __strong> { typedef _Tp type; };
+template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __weak> { typedef _Tp type; };
+template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __autoreleasing> { typedef _Tp type; };
+template <class _Tp> struct __libcpp_remove_objc_qualifiers<_Tp __unsafe_unretained> { typedef _Tp type; };
+#endif
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pointer
+    : public __libcpp_is_pointer<typename __libcpp_remove_objc_qualifiers<typename remove_cv<_Tp>::type>::type> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_pointer_v = is_pointer<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_pointer)
+
+// is_reference
+
+#if __has_keyword(__is_lvalue_reference) && \
+    __has_keyword(__is_rvalue_reference) && \
+    __has_keyword(__is_reference) && !defined(__CUDACC__)
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference : _BoolConstant<__is_lvalue_reference(_Tp)> { };
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference : _BoolConstant<__is_rvalue_reference(_Tp)> { };
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_reference : _BoolConstant<__is_reference(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_reference_v = __is_reference(_Tp);
+template <class _Tp>
+inline constexpr bool is_lvalue_reference_v = __is_lvalue_reference(_Tp);
+template <class _Tp>
+inline constexpr bool is_rvalue_reference_v = __is_rvalue_reference(_Tp);
+#endif
+
+#else // __has_keyword(__is_lvalue_reference) && etc...
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference       : public false_type {};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_lvalue_reference<_Tp&> : public true_type {};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference        : public false_type {};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_rvalue_reference<_Tp&&> : public true_type {};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference        : public false_type {};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&>  : public true_type {};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_reference<_Tp&&> : public true_type {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_reference_v = is_reference<_Tp>::value;
+
+template <class _Tp>
+inline constexpr bool is_lvalue_reference_v = is_lvalue_reference<_Tp>::value;
+
+template <class _Tp>
+inline constexpr bool is_rvalue_reference_v = is_rvalue_reference<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_lvalue_reference) && etc...
+
+// is_union
+
+#if __has_feature(is_union) || defined(_LIBCPP_COMPILER_GCC)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
+    : public integral_constant<bool, __is_union(_Tp)> {};
+
+#else
+
+template <class _Tp> struct __libcpp_union : public false_type {};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_union
+    : public __libcpp_union<typename remove_cv<_Tp>::type> {};
+
+#endif
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_union_v = is_union<_Tp>::value;
+#endif
+
+// is_class
+
+#if __has_feature(is_class) || defined(_LIBCPP_COMPILER_GCC)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
+    : public integral_constant<bool, __is_class(_Tp)> {};
+
+#else
+
+namespace __is_class_imp
+{
+template <class _Tp> char  __test(int _Tp::*);
+template <class _Tp> __two __test(...);
+}
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_class
+    : public integral_constant<bool, sizeof(__is_class_imp::__test<_Tp>(0)) == 1 && !is_union<_Tp>::value> {};
+
+#endif
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_class_v = is_class<_Tp>::value;
+#endif
+
+// is_function
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning(push)
+#pragma warning(disable: 4180)
+#endif
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_function
+    : public _BoolConstant<
+#if defined(__clang__) && !defined(__CUDACC__)
+    __is_function(_Tp)
+#else
+ !(is_reference<_Tp>::value || is_const<const _Tp>::value)
+#endif
+    > {};
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning(pop)
+#endif
+
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_function_v = is_function<_Tp>::value;
+#endif
+
+template <class _Tp> struct __libcpp_is_member_pointer {
+  enum {
+    __is_member = false,
+    __is_func = false,
+    __is_obj = false
+  };
+};
+template <class _Tp, class _Up> struct __libcpp_is_member_pointer<_Tp _Up::*> {
+  enum {
+    __is_member = true,
+    __is_func = is_function<_Tp>::value,
+    __is_obj = !__is_func,
+  };
+};
+
+#if __has_keyword(__is_member_function_pointer) && !defined(__CUDACC__)
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
+    : _BoolConstant<__is_member_function_pointer(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_member_function_pointer_v = __is_member_function_pointer(_Tp);
+#endif
+
+#else // __has_keyword(__is_member_function_pointer)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_function_pointer
+    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_func > {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_member_function_pointer_v = is_member_function_pointer<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_member_function_pointer)
+
+// is_member_pointer
+
+#if __has_keyword(__is_member_pointer) && !defined(__CUDACC__)
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_member_pointer : _BoolConstant<__is_member_pointer(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_member_pointer_v = __is_member_pointer(_Tp);
+#endif
+
+#else // __has_keyword(__is_member_pointer)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_pointer
+ : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_member > {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_member_pointer)
+
+// is_member_object_pointer
+
+#if __has_keyword(__is_member_object_pointer) && !defined(__CUDACC__)
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
+    : _BoolConstant<__is_member_object_pointer(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_member_object_pointer_v = __is_member_object_pointer(_Tp);
+#endif
+
+#else // __has_keyword(__is_member_object_pointer)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_member_object_pointer
+    : public _BoolConstant< __libcpp_is_member_pointer<typename remove_cv<_Tp>::type>::__is_obj >  {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_member_object_pointer_v = is_member_object_pointer<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_member_object_pointer)
+
+// is_enum
+
+#if __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
+    : public integral_constant<bool, __is_enum(_Tp)> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_enum_v = __is_enum(_Tp);
+#endif
+
+#else
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_enum
+    : public integral_constant<bool, !is_void<_Tp>::value             &&
+                                     !is_integral<_Tp>::value         &&
+                                     !is_floating_point<_Tp>::value   &&
+                                     !is_array<_Tp>::value            &&
+                                     !is_pointer<_Tp>::value          &&
+                                     !is_reference<_Tp>::value        &&
+                                     !is_member_pointer<_Tp>::value   &&
+                                     !is_union<_Tp>::value            &&
+                                     !is_class<_Tp>::value            &&
+                                     !is_function<_Tp>::value         > {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_enum_v = is_enum<_Tp>::value;
+#endif
+
+#endif // __has_feature(is_enum) || defined(_LIBCPP_COMPILER_GCC)
+
+// is_arithmetic
+
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_arithmetic
+    : public integral_constant<bool, is_integral<_Tp>::value      ||
+                                     is_floating_point<_Tp>::value> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_arithmetic_v = is_arithmetic<_Tp>::value;
+#endif
+
+// is_fundamental
+
+// Before Clang 10, __is_fundamental didn't work for nullptr_t.
+// In C++03 nullptr_t is library-provided but must still count as "fundamental."
+#if __has_keyword(__is_fundamental) &&                                         \
+    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1000) &&               \
+    !defined(_LIBCPP_CXX03_LANG) && !defined(__CUDACC__)
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_fundamental : _BoolConstant<__is_fundamental(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_fundamental_v = __is_fundamental(_Tp);
+#endif
+
+#else // __has_keyword(__is_fundamental)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_fundamental
+    : public integral_constant<bool, is_void<_Tp>::value        ||
+                                     __is_nullptr_t<_Tp>::value ||
+                                     is_arithmetic<_Tp>::value> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_fundamental_v = is_fundamental<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_fundamental)
+
+// is_scalar
+
+// In C++03 nullptr_t is library-provided but must still count as "scalar."
+#if __has_keyword(__is_scalar) && !defined(_LIBCPP_CXX03_LANG) && !defined(__CUDACC__)
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_scalar : _BoolConstant<__is_scalar(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_scalar_v = __is_scalar(_Tp);
+#endif
+
+#else // __has_keyword(__is_scalar)
+
+template <class _Tp> struct __is_block : false_type {};
+#if defined(_LIBCPP_HAS_EXTENSION_BLOCKS)
+template <class _Rp, class ..._Args> struct __is_block<_Rp (^)(_Args...)> : true_type {};
+#endif
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_scalar
+    : public integral_constant<bool, is_arithmetic<_Tp>::value     ||
+                                     is_member_pointer<_Tp>::value ||
+                                     is_pointer<_Tp>::value        ||
+                                     __is_nullptr_t<_Tp>::value    ||
+                                     __is_block<_Tp>::value        ||
+                                     is_enum<_Tp>::value           > {};
+
+template <> struct _LIBCPP_TEMPLATE_VIS is_scalar<nullptr_t> : public true_type {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_scalar)
+
+// is_object
+
+#if __has_keyword(__is_object) && !defined(__CUDACC__)
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_object : _BoolConstant<__is_object(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_object_v = __is_object(_Tp);
+#endif
+
+#else // __has_keyword(__is_object)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_object
+    : public integral_constant<bool, is_scalar<_Tp>::value ||
+                                     is_array<_Tp>::value  ||
+                                     is_union<_Tp>::value  ||
+                                     is_class<_Tp>::value  > {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_object_v = is_object<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_object)
+
+// is_compound
+
+// >= 11 because in C++03 nullptr isn't actually nullptr
+#if __has_keyword(__is_compound) && !defined(_LIBCPP_CXX03_LANG) && !defined(__CUDACC__)
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_compound : _BoolConstant<__is_compound(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_compound_v = __is_compound(_Tp);
+#endif
+
+#else // __has_keyword(__is_compound)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_compound
+    : public integral_constant<bool, !is_fundamental<_Tp>::value> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_compound_v = is_compound<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_compound)
+
+// __is_referenceable  [defns.referenceable]
+
+struct __is_referenceable_impl {
+    template <class _Tp> static _Tp& __test(int);
+    template <class _Tp> static __two __test(...);
+};
+
+template <class _Tp>
+struct __is_referenceable : integral_constant<bool,
+    _IsNotSame<decltype(__is_referenceable_impl::__test<_Tp>(0)), __two>::value> {};
+
+
+// add_const
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_const {
+  typedef _LIBCPP_NODEBUG const _Tp type;
+};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using add_const_t = typename add_const<_Tp>::type;
+#endif
+
+// add_volatile
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_volatile {
+  typedef _LIBCPP_NODEBUG volatile _Tp type;
+};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using add_volatile_t = typename add_volatile<_Tp>::type;
+#endif
+
+// add_cv
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_cv {
+  typedef _LIBCPP_NODEBUG const volatile _Tp type;
+};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using add_cv_t = typename add_cv<_Tp>::type;
+#endif
+
+// remove_reference
+
+#if __has_keyword(__remove_reference)
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS remove_reference { typedef __remove_reference(_Tp) type; };
+
+#else // __has_keyword(__remove_reference)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference        {typedef _LIBCPP_NODEBUG _Tp type;};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&>  {typedef _LIBCPP_NODEBUG _Tp type;};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_reference<_Tp&&> {typedef _LIBCPP_NODEBUG _Tp type;};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using remove_reference_t = typename remove_reference<_Tp>::type;
+#endif
+
+#endif // __has_keyword(__remove_reference)
+
+// add_lvalue_reference
+
+template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_lvalue_reference_impl            { typedef _LIBCPP_NODEBUG _Tp  type; };
+template <class _Tp                                       > struct __add_lvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG _Tp& type; };
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_lvalue_reference
+{typedef _LIBCPP_NODEBUG typename  __add_lvalue_reference_impl<_Tp>::type type;};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using add_lvalue_reference_t = typename add_lvalue_reference<_Tp>::type;
+#endif
+
+template <class _Tp, bool = __is_referenceable<_Tp>::value> struct __add_rvalue_reference_impl            { typedef _LIBCPP_NODEBUG _Tp   type; };
+template <class _Tp                                       > struct __add_rvalue_reference_impl<_Tp, true> { typedef _LIBCPP_NODEBUG _Tp&& type; };
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_rvalue_reference
+{typedef _LIBCPP_NODEBUG typename __add_rvalue_reference_impl<_Tp>::type type;};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using add_rvalue_reference_t = typename add_rvalue_reference<_Tp>::type;
+#endif
+
+// __uncvref
+
+template <class _Tp>
+struct __uncvref  {
+    typedef _LIBCPP_NODEBUG typename remove_cv<typename remove_reference<_Tp>::type>::type type;
+};
+
+template <class _Tp>
+struct __unconstref {
+    typedef _LIBCPP_NODEBUG typename remove_const<typename remove_reference<_Tp>::type>::type type;
+};
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp>
+using __uncvref_t _LIBCPP_NODEBUG = typename __uncvref<_Tp>::type;
+#endif
+
+// __is_same_uncvref
+
+template <class _Tp, class _Up>
+struct __is_same_uncvref : _IsSame<typename __uncvref<_Tp>::type,
+                                   typename __uncvref<_Up>::type> {};
+
+// C++20, enabled for C++17 in Arcadia
+#if _LIBCPP_STD_VER > 14
+// remove_cvref - same as __uncvref
+template <class _Tp>
+struct remove_cvref : public __uncvref<_Tp> {};
+
+template <class _Tp> using remove_cvref_t = typename remove_cvref<_Tp>::type;
+#endif
+
+
+struct __any
+{
+    __any(...);
+};
+
+// remove_pointer
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer                      {typedef _LIBCPP_NODEBUG _Tp type;};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp*>                {typedef _LIBCPP_NODEBUG _Tp type;};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const>          {typedef _LIBCPP_NODEBUG _Tp type;};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* volatile>       {typedef _LIBCPP_NODEBUG _Tp type;};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_pointer<_Tp* const volatile> {typedef _LIBCPP_NODEBUG _Tp type;};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using remove_pointer_t = typename remove_pointer<_Tp>::type;
+#endif
+
+// add_pointer
+
+template <class _Tp,
+        bool = __is_referenceable<_Tp>::value ||
+                _IsSame<typename remove_cv<_Tp>::type, void>::value>
+struct __add_pointer_impl
+    {typedef _LIBCPP_NODEBUG typename remove_reference<_Tp>::type* type;};
+template <class _Tp> struct __add_pointer_impl<_Tp, false>
+    {typedef _LIBCPP_NODEBUG _Tp type;};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS add_pointer
+    {typedef _LIBCPP_NODEBUG typename __add_pointer_impl<_Tp>::type type;};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using add_pointer_t = typename add_pointer<_Tp>::type;
+#endif
+
+// type_identity
+#if _LIBCPP_STD_VER > 17
+template<class _Tp> struct type_identity { typedef _Tp type; };
+template<class _Tp> using type_identity_t = typename type_identity<_Tp>::type;
+#endif
+
+// is_signed
+
+// Before Clang 10, __is_signed didn't work for floating-point types or enums.
+#if __has_keyword(__is_signed) &&                                              \
+    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1000) &&               \
+    !defined(__CUDACC__)
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_signed : _BoolConstant<__is_signed(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_signed_v = __is_signed(_Tp);
+#endif
+
+#else // __has_keyword(__is_signed)
+
+template <class _Tp, bool = is_integral<_Tp>::value>
+struct __libcpp_is_signed_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(-1) < _Tp(0)) {};
+
+template <class _Tp>
+struct __libcpp_is_signed_impl<_Tp, false> : public true_type {};  // floating point
+
+template <class _Tp, bool = is_arithmetic<_Tp>::value>
+struct __libcpp_is_signed : public __libcpp_is_signed_impl<_Tp> {};
+
+template <class _Tp> struct __libcpp_is_signed<_Tp, false> : public false_type {};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_signed : public __libcpp_is_signed<_Tp> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_signed_v = is_signed<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_signed)
+
+// is_unsigned
+
+// Before Clang 13, __is_unsigned returned true for enums with signed underlying type.
+// No currently-released version of AppleClang contains the fixed intrinsic.
+#if __has_keyword(__is_unsigned) &&                                            \
+    !(defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER < 1300) &&               \
+    !defined(_LIBCPP_APPLE_CLANG_VER) && !defined(__CUDACC__)
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_unsigned : _BoolConstant<__is_unsigned(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_unsigned_v = __is_unsigned(_Tp);
+#endif
+
+#else // __has_keyword(__is_unsigned)
+
+template <class _Tp, bool = is_integral<_Tp>::value>
+struct __libcpp_is_unsigned_impl : public _LIBCPP_BOOL_CONSTANT(_Tp(0) < _Tp(-1)) {};
+
+template <class _Tp>
+struct __libcpp_is_unsigned_impl<_Tp, false> : public false_type {};  // floating point
+
+template <class _Tp, bool = is_arithmetic<_Tp>::value>
+struct __libcpp_is_unsigned : public __libcpp_is_unsigned_impl<_Tp> {};
+
+template <class _Tp> struct __libcpp_is_unsigned<_Tp, false> : public false_type {};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unsigned : public __libcpp_is_unsigned<_Tp> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_unsigned)
+
+// rank
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank
+    : public integral_constant<size_t, 0> {};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[]>
+    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
+template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS rank<_Tp[_Np]>
+    : public integral_constant<size_t, rank<_Tp>::value + 1> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr size_t rank_v = rank<_Tp>::value;
+#endif
+
+// extent
+
+#if __has_keyword(__array_extent) && !defined(__CUDACC__)
+
+template<class _Tp, size_t _Dim = 0>
+struct _LIBCPP_TEMPLATE_VIS extent
+    : integral_constant<size_t, __array_extent(_Tp, _Dim)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, unsigned _Ip = 0>
+inline constexpr size_t extent_v = __array_extent(_Tp, _Ip);
+#endif
+
+#else // __has_keyword(__array_extent)
+
+template <class _Tp, unsigned _Ip = 0> struct _LIBCPP_TEMPLATE_VIS extent
+    : public integral_constant<size_t, 0> {};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], 0>
+    : public integral_constant<size_t, 0> {};
+template <class _Tp, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[], _Ip>
+    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
+template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], 0>
+    : public integral_constant<size_t, _Np> {};
+template <class _Tp, size_t _Np, unsigned _Ip> struct _LIBCPP_TEMPLATE_VIS extent<_Tp[_Np], _Ip>
+    : public integral_constant<size_t, extent<_Tp, _Ip-1>::value> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, unsigned _Ip = 0>
+inline constexpr size_t extent_v = extent<_Tp, _Ip>::value;
+#endif
+
+#endif // __has_keyword(__array_extent)
+
+// remove_extent
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent
+    {typedef _Tp type;};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[]>
+    {typedef _Tp type;};
+template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_extent<_Tp[_Np]>
+    {typedef _Tp type;};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using remove_extent_t = typename remove_extent<_Tp>::type;
+#endif
+
+// remove_all_extents
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents
+    {typedef _Tp type;};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[]>
+    {typedef typename remove_all_extents<_Tp>::type type;};
+template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS remove_all_extents<_Tp[_Np]>
+    {typedef typename remove_all_extents<_Tp>::type type;};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using remove_all_extents_t = typename remove_all_extents<_Tp>::type;
+#endif
+
+#if _LIBCPP_STD_VER > 17
+// is_bounded_array
+
+template <class>                 struct _LIBCPP_TEMPLATE_VIS is_bounded_array           : false_type {};
+template <class _Tp, size_t _Np> struct _LIBCPP_TEMPLATE_VIS is_bounded_array<_Tp[_Np]> : true_type {};
+
+template <class _Tp>
+inline constexpr
+bool is_bounded_array_v  = is_bounded_array<_Tp>::value;
+
+// is_unbounded_array
+
+template <class>     struct _LIBCPP_TEMPLATE_VIS is_unbounded_array        : false_type {};
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_unbounded_array<_Tp[]> : true_type {};
+
+template <class _Tp>
+inline constexpr
+bool is_unbounded_array_v  = is_unbounded_array<_Tp>::value;
+#endif
+
+// decay
+
+template <class _Up, bool>
+struct __decay {
+    typedef _LIBCPP_NODEBUG typename remove_cv<_Up>::type type;
+};
+
+template <class _Up>
+struct __decay<_Up, true> {
+public:
+    typedef _LIBCPP_NODEBUG typename conditional
+                     <
+                         is_array<_Up>::value,
+                         typename remove_extent<_Up>::type*,
+                         typename conditional
+                         <
+                              is_function<_Up>::value,
+                              typename add_pointer<_Up>::type,
+                              typename remove_cv<_Up>::type
+                         >::type
+                     >::type type;
+};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS decay
+{
+private:
+    typedef _LIBCPP_NODEBUG typename remove_reference<_Tp>::type _Up;
+public:
+    typedef _LIBCPP_NODEBUG typename __decay<_Up, __is_referenceable<_Up>::value>::type type;
+};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using decay_t = typename decay<_Tp>::type;
+#endif
+
+// is_abstract
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_abstract
+    : public integral_constant<bool, __is_abstract(_Tp)> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_abstract_v = is_abstract<_Tp>::value;
+#endif
+
+// is_final
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
+__libcpp_is_final : public integral_constant<bool, __is_final(_Tp)> {};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
+is_final : public integral_constant<bool, __is_final(_Tp)> {};
+#endif
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_final_v = is_final<_Tp>::value;
+#endif
+
+// is_aggregate
+#if _LIBCPP_STD_VER > 14
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS
+is_aggregate : public integral_constant<bool, __is_aggregate(_Tp)> {};
+
+template <class _Tp>
+inline constexpr bool is_aggregate_v = is_aggregate<_Tp>::value;
+
+#endif // _LIBCPP_STD_VER > 14
+
+// is_base_of
+
+template <class _Bp, class _Dp>
+struct _LIBCPP_TEMPLATE_VIS is_base_of
+    : public integral_constant<bool, __is_base_of(_Bp, _Dp)> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Bp, class _Dp>
+inline constexpr bool is_base_of_v = is_base_of<_Bp, _Dp>::value;
+#endif
+
+// __is_core_convertible
+
+// [conv.general]/3 says "E is convertible to T" whenever "T t=E;" is well-formed.
+// We can't test for that, but we can test implicit convertibility by passing it
+// to a function. Notice that __is_core_convertible<void,void> is false,
+// and __is_core_convertible<immovable-type,immovable-type> is true in C++17 and later.
+
+template <class _Tp, class _Up, class = void>
+struct __is_core_convertible : public false_type {};
+
+template <class _Tp, class _Up>
+struct __is_core_convertible<_Tp, _Up, decltype(
+    static_cast<void(*)(_Up)>(0) ( static_cast<_Tp(*)()>(0)() )
+)> : public true_type {};
+
+// is_convertible
+
+#if __has_feature(is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK)
+
+template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
+    : public integral_constant<bool, __is_convertible_to(_T1, _T2)> {};
+
+#else  // __has_feature(is_convertible_to)
+
+namespace __is_convertible_imp
+{
+template <class _Tp> void  __test_convert(_Tp);
+
+template <class _From, class _To, class = void>
+struct __is_convertible_test : public false_type {};
+
+template <class _From, class _To>
+struct __is_convertible_test<_From, _To,
+    decltype(__is_convertible_imp::__test_convert<_To>(declval<_From>()))> : public true_type
+{};
+
+template <class _Tp, bool _IsArray =    is_array<_Tp>::value,
+                     bool _IsFunction = is_function<_Tp>::value,
+                     bool _IsVoid =     is_void<_Tp>::value>
+                     struct __is_array_function_or_void                          {enum {value = 0};};
+template <class _Tp> struct __is_array_function_or_void<_Tp, true, false, false> {enum {value = 1};};
+template <class _Tp> struct __is_array_function_or_void<_Tp, false, true, false> {enum {value = 2};};
+template <class _Tp> struct __is_array_function_or_void<_Tp, false, false, true> {enum {value = 3};};
+}
+
+template <class _Tp,
+    unsigned = __is_convertible_imp::__is_array_function_or_void<typename remove_reference<_Tp>::type>::value>
+struct __is_convertible_check
+{
+    static const size_t __v = 0;
+};
+
+template <class _Tp>
+struct __is_convertible_check<_Tp, 0>
+{
+    static const size_t __v = sizeof(_Tp);
+};
+
+template <class _T1, class _T2,
+    unsigned _T1_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T1>::value,
+    unsigned _T2_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T2>::value>
+struct __is_convertible
+    : public integral_constant<bool,
+        __is_convertible_imp::__is_convertible_test<_T1, _T2>::value
+    >
+{};
+
+template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 1> : public false_type {};
+template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 1> : public false_type {};
+template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 1> : public false_type {};
+template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 1> : public false_type {};
+
+template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 2> : public false_type {};
+template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 2> : public false_type {};
+template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 2> : public false_type {};
+template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 2> : public false_type {};
+
+template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 3> : public false_type {};
+template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 3> : public false_type {};
+template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 3> : public false_type {};
+template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 3> : public true_type {};
+
+template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible
+    : public __is_convertible<_T1, _T2>
+{
+    static const size_t __complete_check1 = __is_convertible_check<_T1>::__v;
+    static const size_t __complete_check2 = __is_convertible_check<_T2>::__v;
+};
+
+#endif // __has_feature(is_convertible_to)
+
+#if _LIBCPP_STD_VER > 14
+template <class _From, class _To>
+inline constexpr bool is_convertible_v = is_convertible<_From, _To>::value;
+#endif
+
+// is_nothrow_convertible
+
+#if _LIBCPP_STD_VER > 17
+
+template <typename _Tp>
+static void __test_noexcept(_Tp) noexcept;
+
+template<typename _Fm, typename _To>
+static bool_constant<noexcept(_VSTD::__test_noexcept<_To>(declval<_Fm>()))>
+__is_nothrow_convertible_test();
+
+template <typename _Fm, typename _To>
+struct __is_nothrow_convertible_helper: decltype(__is_nothrow_convertible_test<_Fm, _To>())
+{ };
+
+template <typename _Fm, typename _To>
+struct is_nothrow_convertible : _Or<
+    _And<is_void<_To>, is_void<_Fm>>,
+    _Lazy<_And, is_convertible<_Fm, _To>, __is_nothrow_convertible_helper<_Fm, _To>>
+>::type { };
+
+template <typename _Fm, typename _To>
+inline constexpr bool is_nothrow_convertible_v = is_nothrow_convertible<_Fm, _To>::value;
+
+#endif // _LIBCPP_STD_VER > 17
+
+// is_empty
+
+#if __has_feature(is_empty) || defined(_LIBCPP_COMPILER_GCC)
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_empty
+    : public integral_constant<bool, __is_empty(_Tp)> {};
+
+#else  // __has_feature(is_empty)
+
+template <class _Tp>
+struct __is_empty1
+    : public _Tp
+{
+    double __lx;
+};
+
+struct __is_empty2
+{
+    double __lx;
+};
+
+template <class _Tp, bool = is_class<_Tp>::value>
+struct __libcpp_empty : public integral_constant<bool, sizeof(__is_empty1<_Tp>) == sizeof(__is_empty2)> {};
+
+template <class _Tp> struct __libcpp_empty<_Tp, false> : public false_type {};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_empty : public __libcpp_empty<_Tp> {};
+
+#endif // __has_feature(is_empty)
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_empty_v = is_empty<_Tp>::value;
+#endif
+
+// is_polymorphic
+
+#if __has_feature(is_polymorphic) || defined(_LIBCPP_COMPILER_MSVC)
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_polymorphic
+    : public integral_constant<bool, __is_polymorphic(_Tp)> {};
+
+#else
+
+template<typename _Tp> char &__is_polymorphic_impl(
+    typename enable_if<sizeof((_Tp*)dynamic_cast<const volatile void*>(declval<_Tp*>())) != 0,
+                       int>::type);
+template<typename _Tp> __two &__is_polymorphic_impl(...);
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_polymorphic
+    : public integral_constant<bool, sizeof(__is_polymorphic_impl<_Tp>(0)) == 1> {};
+
+#endif // __has_feature(is_polymorphic)
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_polymorphic_v = is_polymorphic<_Tp>::value;
+#endif
+
+// has_virtual_destructor
+
+#if __has_feature(has_virtual_destructor) || defined(_LIBCPP_COMPILER_GCC)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
+    : public integral_constant<bool, __has_virtual_destructor(_Tp)> {};
+
+#else
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_virtual_destructor
+    : public false_type {};
+
+#endif
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool has_virtual_destructor_v = has_virtual_destructor<_Tp>::value;
+#endif
+
+// has_unique_object_representations
+
+#if _LIBCPP_STD_VER > 14
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS has_unique_object_representations
+    : public integral_constant<bool,
+       __has_unique_object_representations(remove_cv_t<remove_all_extents_t<_Tp>>)> {};
+
+template <class _Tp>
+inline constexpr bool has_unique_object_representations_v = has_unique_object_representations<_Tp>::value;
+
+#endif
+
+// alignment_of
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS alignment_of
+    : public integral_constant<size_t, _LIBCPP_ALIGNOF(_Tp)> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr size_t alignment_of_v = alignment_of<_Tp>::value;
+#endif
+
+// aligned_storage
+
+template <class _Hp, class _Tp>
+struct __type_list
+{
+    typedef _Hp _Head;
+    typedef _Tp _Tail;
+};
+
+struct __nat
+{
+#ifndef _LIBCPP_CXX03_LANG
+    __nat() = delete;
+    __nat(const __nat&) = delete;
+    __nat& operator=(const __nat&) = delete;
+    ~__nat() = delete;
+#endif
+};
+
+template <class _Tp>
+struct __align_type
+{
+    static const size_t value = _LIBCPP_PREFERRED_ALIGNOF(_Tp);
+    typedef _Tp type;
+};
+
+struct __struct_double {long double __lx;};
+struct __struct_double4 {double __lx[4];};
+
+typedef
+    __type_list<__align_type<unsigned char>,
+    __type_list<__align_type<unsigned short>,
+    __type_list<__align_type<unsigned int>,
+    __type_list<__align_type<unsigned long>,
+    __type_list<__align_type<unsigned long long>,
+    __type_list<__align_type<double>,
+    __type_list<__align_type<long double>,
+    __type_list<__align_type<__struct_double>,
+    __type_list<__align_type<__struct_double4>,
+    __type_list<__align_type<int*>,
+    __nat
+    > > > > > > > > > > __all_types;
+
+template <size_t _Align>
+struct _ALIGNAS(_Align) __fallback_overaligned {};
+
+template <class _TL, size_t _Align> struct __find_pod;
+
+template <class _Hp, size_t _Align>
+struct __find_pod<__type_list<_Hp, __nat>, _Align>
+{
+    typedef typename conditional<
+                             _Align == _Hp::value,
+                             typename _Hp::type,
+                             __fallback_overaligned<_Align>
+                         >::type type;
+};
+
+template <class _Hp, class _Tp, size_t _Align>
+struct __find_pod<__type_list<_Hp, _Tp>, _Align>
+{
+    typedef typename conditional<
+                             _Align == _Hp::value,
+                             typename _Hp::type,
+                             typename __find_pod<_Tp, _Align>::type
+                         >::type type;
+};
+
+template <class _TL, size_t _Len> struct __find_max_align;
+
+template <class _Hp, size_t _Len>
+struct __find_max_align<__type_list<_Hp, __nat>, _Len> : public integral_constant<size_t, _Hp::value> {};
+
+template <size_t _Len, size_t _A1, size_t _A2>
+struct __select_align
+{
+private:
+    static const size_t __min = _A2 < _A1 ? _A2 : _A1;
+    static const size_t __max = _A1 < _A2 ? _A2 : _A1;
+public:
+    static const size_t value = _Len < __max ? __min : __max;
+};
+
+template <class _Hp, class _Tp, size_t _Len>
+struct __find_max_align<__type_list<_Hp, _Tp>, _Len>
+    : public integral_constant<size_t, __select_align<_Len, _Hp::value, __find_max_align<_Tp, _Len>::value>::value> {};
+
+template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
+struct _LIBCPP_TEMPLATE_VIS aligned_storage
+{
+    typedef typename __find_pod<__all_types, _Align>::type _Aligner;
+    union type
+    {
+        _Aligner __align;
+        unsigned char __data[(_Len + _Align - 1)/_Align * _Align];
+    };
+};
+
+#if _LIBCPP_STD_VER > 11
+template <size_t _Len, size_t _Align = __find_max_align<__all_types, _Len>::value>
+    using aligned_storage_t = typename aligned_storage<_Len, _Align>::type;
+#endif
+
+// MSVC compiler doesn't support more that 4 byte alignment on the stack on Win32.
+// If you try to pass parameter which is aligned by alignas to 8 or more bytes
+// on Win32, MSVC throws compile error C2719.
+// To avoid this compile error we delete all alignas specializations and use
+// union alignment instead. Just like for double, this will mean that 8 bytes
+// aligned types will only be aligned to 4 bytes on the stack.
+// Larger alignments will generate assert error which is allowed by the standard
+// since it is implementation-defined behavior. Default _Align argument will never
+// be more than 8 bytes on Win32 and so will not generate assert errors.
+#if !(defined(_LIBCPP_COMPILER_MSVC) && defined(_M_IX86))
+
+#define _CREATE_ALIGNED_STORAGE_SPECIALIZATION(n) \
+template <size_t _Len>\
+struct _LIBCPP_TEMPLATE_VIS aligned_storage<_Len, n>\
+{\
+    struct _ALIGNAS(n) type\
+    {\
+        unsigned char __lx[(_Len + n - 1)/n * n];\
+    };\
+}
+
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1);
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2);
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4);
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x8);
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x10);
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x20);
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x40);
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x80);
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x100);
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x200);
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x400);
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x800);
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x1000);
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x2000);
+// PE/COFF does not support alignment beyond 8192 (=0x2000)
+#if !defined(_LIBCPP_OBJECT_FORMAT_COFF)
+_CREATE_ALIGNED_STORAGE_SPECIALIZATION(0x4000);
+#endif // !defined(_LIBCPP_OBJECT_FORMAT_COFF)
+
+#undef _CREATE_ALIGNED_STORAGE_SPECIALIZATION
+#endif  // !(defined(_LIBCPP_COMPILER_MSVC) && defined(_M_IX86))
+
+
+// aligned_union
+
+template <size_t _I0, size_t ..._In>
+struct __static_max;
+
+template <size_t _I0>
+struct __static_max<_I0>
+{
+    static const size_t value = _I0;
+};
+
+template <size_t _I0, size_t _I1, size_t ..._In>
+struct __static_max<_I0, _I1, _In...>
+{
+    static const size_t value = _I0 >= _I1 ? __static_max<_I0, _In...>::value :
+                                             __static_max<_I1, _In...>::value;
+};
+
+template <size_t _Len, class _Type0, class ..._Types>
+struct aligned_union
+{
+    static const size_t alignment_value = __static_max<_LIBCPP_PREFERRED_ALIGNOF(_Type0),
+                                                       _LIBCPP_PREFERRED_ALIGNOF(_Types)...>::value;
+    static const size_t __len = __static_max<_Len, sizeof(_Type0),
+                                             sizeof(_Types)...>::value;
+    typedef typename aligned_storage<__len, alignment_value>::type type;
+};
+
+#if _LIBCPP_STD_VER > 11
+template <size_t _Len, class ..._Types> using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
+#endif
+
+template <class _Tp>
+struct __numeric_type
+{
+   static void __test(...);
+   static float __test(float);
+   static double __test(char);
+   static double __test(int);
+   static double __test(unsigned);
+   static double __test(long);
+   static double __test(unsigned long);
+   static double __test(long long);
+   static double __test(unsigned long long);
+   static double __test(double);
+   static long double __test(long double);
+
+   typedef decltype(__test(declval<_Tp>())) type;
+   static const bool value = _IsNotSame<type, void>::value;
+};
+
+template <>
+struct __numeric_type<void>
+{
+   static const bool value = true;
+};
+
+// __promote
+
+template <class _A1, class _A2 = void, class _A3 = void,
+          bool = __numeric_type<_A1>::value &&
+                 __numeric_type<_A2>::value &&
+                 __numeric_type<_A3>::value>
+class __promote_imp
+{
+public:
+    static const bool value = false;
+};
+
+template <class _A1, class _A2, class _A3>
+class __promote_imp<_A1, _A2, _A3, true>
+{
+private:
+    typedef typename __promote_imp<_A1>::type __type1;
+    typedef typename __promote_imp<_A2>::type __type2;
+    typedef typename __promote_imp<_A3>::type __type3;
+public:
+    typedef decltype(__type1() + __type2() + __type3()) type;
+    static const bool value = true;
+};
+
+template <class _A1, class _A2>
+class __promote_imp<_A1, _A2, void, true>
+{
+private:
+    typedef typename __promote_imp<_A1>::type __type1;
+    typedef typename __promote_imp<_A2>::type __type2;
+public:
+    typedef decltype(__type1() + __type2()) type;
+    static const bool value = true;
+};
+
+template <class _A1>
+class __promote_imp<_A1, void, void, true>
+{
+public:
+    typedef typename __numeric_type<_A1>::type type;
+    static const bool value = true;
+};
+
+template <class _A1, class _A2 = void, class _A3 = void>
+class __promote : public __promote_imp<_A1, _A2, _A3> {};
+
+// make_signed / make_unsigned
+
+typedef
+    __type_list<signed char,
+    __type_list<signed short,
+    __type_list<signed int,
+    __type_list<signed long,
+    __type_list<signed long long,
+#ifndef _LIBCPP_HAS_NO_INT128
+    __type_list<__int128_t,
+#endif
+    __nat
+#ifndef _LIBCPP_HAS_NO_INT128
+    >
+#endif
+    > > > > > __signed_types;
+
+typedef
+    __type_list<unsigned char,
+    __type_list<unsigned short,
+    __type_list<unsigned int,
+    __type_list<unsigned long,
+    __type_list<unsigned long long,
+#ifndef _LIBCPP_HAS_NO_INT128
+    __type_list<__uint128_t,
+#endif
+    __nat
+#ifndef _LIBCPP_HAS_NO_INT128
+    >
+#endif
+    > > > > > __unsigned_types;
+
+template <class _TypeList, size_t _Size, bool = _Size <= sizeof(typename _TypeList::_Head)> struct __find_first;
+
+template <class _Hp, class _Tp, size_t _Size>
+struct __find_first<__type_list<_Hp, _Tp>, _Size, true>
+{
+    typedef _LIBCPP_NODEBUG _Hp type;
+};
+
+template <class _Hp, class _Tp, size_t _Size>
+struct __find_first<__type_list<_Hp, _Tp>, _Size, false>
+{
+    typedef _LIBCPP_NODEBUG typename __find_first<_Tp, _Size>::type type;
+};
+
+template <class _Tp, class _Up, bool = is_const<typename remove_reference<_Tp>::type>::value,
+                             bool = is_volatile<typename remove_reference<_Tp>::type>::value>
+struct __apply_cv
+{
+    typedef _LIBCPP_NODEBUG _Up type;
+};
+
+template <class _Tp, class _Up>
+struct __apply_cv<_Tp, _Up, true, false>
+{
+    typedef _LIBCPP_NODEBUG const _Up type;
+};
+
+template <class _Tp, class _Up>
+struct __apply_cv<_Tp, _Up, false, true>
+{
+    typedef volatile _Up type;
+};
+
+template <class _Tp, class _Up>
+struct __apply_cv<_Tp, _Up, true, true>
+{
+    typedef const volatile _Up type;
+};
+
+template <class _Tp, class _Up>
+struct __apply_cv<_Tp&, _Up, false, false>
+{
+    typedef _Up& type;
+};
+
+template <class _Tp, class _Up>
+struct __apply_cv<_Tp&, _Up, true, false>
+{
+    typedef const _Up& type;
+};
+
+template <class _Tp, class _Up>
+struct __apply_cv<_Tp&, _Up, false, true>
+{
+    typedef volatile _Up& type;
+};
+
+template <class _Tp, class _Up>
+struct __apply_cv<_Tp&, _Up, true, true>
+{
+    typedef const volatile _Up& type;
+};
+
+template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
+struct __make_signed {};
+
+template <class _Tp>
+struct __make_signed<_Tp, true>
+{
+    typedef typename __find_first<__signed_types, sizeof(_Tp)>::type type;
+};
+
+template <> struct __make_signed<bool,               true> {};
+template <> struct __make_signed<  signed short,     true> {typedef short     type;};
+template <> struct __make_signed<unsigned short,     true> {typedef short     type;};
+template <> struct __make_signed<  signed int,       true> {typedef int       type;};
+template <> struct __make_signed<unsigned int,       true> {typedef int       type;};
+template <> struct __make_signed<  signed long,      true> {typedef long      type;};
+template <> struct __make_signed<unsigned long,      true> {typedef long      type;};
+template <> struct __make_signed<  signed long long, true> {typedef long long type;};
+template <> struct __make_signed<unsigned long long, true> {typedef long long type;};
+#ifndef _LIBCPP_HAS_NO_INT128
+template <> struct __make_signed<__int128_t,         true> {typedef __int128_t type;};
+template <> struct __make_signed<__uint128_t,        true> {typedef __int128_t type;};
+#endif
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS make_signed
+{
+    typedef typename __apply_cv<_Tp, typename __make_signed<typename remove_cv<_Tp>::type>::type>::type type;
+};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using make_signed_t = typename make_signed<_Tp>::type;
+#endif
+
+template <class _Tp, bool = is_integral<_Tp>::value || is_enum<_Tp>::value>
+struct __make_unsigned {};
+
+template <class _Tp>
+struct __make_unsigned<_Tp, true>
+{
+    typedef typename __find_first<__unsigned_types, sizeof(_Tp)>::type type;
+};
+
+template <> struct __make_unsigned<bool,               true> {};
+template <> struct __make_unsigned<  signed short,     true> {typedef unsigned short     type;};
+template <> struct __make_unsigned<unsigned short,     true> {typedef unsigned short     type;};
+template <> struct __make_unsigned<  signed int,       true> {typedef unsigned int       type;};
+template <> struct __make_unsigned<unsigned int,       true> {typedef unsigned int       type;};
+template <> struct __make_unsigned<  signed long,      true> {typedef unsigned long      type;};
+template <> struct __make_unsigned<unsigned long,      true> {typedef unsigned long      type;};
+template <> struct __make_unsigned<  signed long long, true> {typedef unsigned long long type;};
+template <> struct __make_unsigned<unsigned long long, true> {typedef unsigned long long type;};
+#ifndef _LIBCPP_HAS_NO_INT128
+template <> struct __make_unsigned<__int128_t,         true> {typedef __uint128_t        type;};
+template <> struct __make_unsigned<__uint128_t,        true> {typedef __uint128_t        type;};
+#endif
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS make_unsigned
+{
+    typedef typename __apply_cv<_Tp, typename __make_unsigned<typename remove_cv<_Tp>::type>::type>::type type;
+};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using make_unsigned_t = typename make_unsigned<_Tp>::type;
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp>
+_LIBCPP_HIDE_FROM_ABI constexpr
+typename make_unsigned<_Tp>::type __to_unsigned_like(_Tp __x) noexcept {
+    return static_cast<typename make_unsigned<_Tp>::type>(__x);
+}
+#endif
+
+#if _LIBCPP_STD_VER > 14
+template <class...> using void_t = void;
+#endif
+
+#if _LIBCPP_STD_VER > 17
+// Let COND_RES(X, Y) be:
+template <class _Tp, class _Up>
+using __cond_type = decltype(false ? declval<_Tp>() : declval<_Up>());
+
+template <class _Tp, class _Up, class = void>
+struct __common_type3 {};
+
+// sub-bullet 4 - "if COND_RES(CREF(D1), CREF(D2)) denotes a type..."
+template <class _Tp, class _Up>
+struct __common_type3<_Tp, _Up, void_t<__cond_type<const _Tp&, const _Up&>>>
+{
+    using type = remove_cvref_t<__cond_type<const _Tp&, const _Up&>>;
+};
+
+template <class _Tp, class _Up, class = void>
+struct __common_type2_imp : __common_type3<_Tp, _Up> {};
+#else
+template <class _Tp, class _Up, class = void>
+struct __common_type2_imp {};
+#endif
+
+// sub-bullet 3 - "if decay_t<decltype(false ? declval<D1>() : declval<D2>())> ..."
+template <class _Tp, class _Up>
+struct __common_type2_imp<_Tp, _Up,
+                          typename __void_t<decltype(
+                                            true ? declval<_Tp>() : declval<_Up>()
+                                            )>::type>
+{
+  typedef _LIBCPP_NODEBUG typename decay<decltype(
+                         true ? declval<_Tp>() : declval<_Up>()
+                         )>::type type;
+};
+
+template <class, class = void>
+struct __common_type_impl {};
+
+// Clang provides variadic templates in C++03 as an extension.
+#if !defined(_LIBCPP_CXX03_LANG) || defined(__clang__)
+# define _LIBCPP_OPTIONAL_PACK(...) , __VA_ARGS__
+template <class... Tp>
+struct __common_types;
+template <class... _Tp>
+struct _LIBCPP_TEMPLATE_VIS common_type;
+#else
+# define _LIBCPP_OPTIONAL_PACK(...)
+struct __no_arg;
+template <class _Tp, class _Up, class = __no_arg>
+struct __common_types;
+template <class _Tp = __no_arg, class _Up = __no_arg, class _Vp = __no_arg,
+          class _Unused = __no_arg>
+struct common_type {
+  static_assert(sizeof(_Unused) == 0,
+                "common_type accepts at most 3 arguments in C++03");
+};
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Up>
+struct __common_type_impl<
+    __common_types<_Tp, _Up>,
+    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
+{
+  typedef typename common_type<_Tp, _Up>::type type;
+};
+
+template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
+struct __common_type_impl<
+    __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>,
+    typename __void_t<typename common_type<_Tp, _Up>::type>::type>
+    : __common_type_impl<__common_types<typename common_type<_Tp, _Up>::type,
+                                        _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {
+};
+
+// bullet 1 - sizeof...(Tp) == 0
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS common_type<> {};
+
+// bullet 2 - sizeof...(Tp) == 1
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS common_type<_Tp>
+    : public common_type<_Tp, _Tp> {};
+
+// sub-bullet 1 - "If is_same_v<T1, D1> is false or ..."
+template <class _Tp, class _Up>
+struct _LIBCPP_TEMPLATE_VIS common_type<_Tp, _Up>
+    : conditional<
+        _IsSame<_Tp, typename decay<_Tp>::type>::value && _IsSame<_Up, typename decay<_Up>::type>::value,
+        // Fix for MSVC which thinks that std::common_type<int, void>::type == void.
+        __common_type2_imp<_Tp, _Up, typename conditional<is_void<_Tp>::value ^ is_void<_Up>::value, int, void>::type>,
+        common_type<typename decay<_Tp>::type, typename decay<_Up>::type>
+    >::type
+{};
+
+// bullet 4 - sizeof...(Tp) > 2
+
+template <class _Tp, class _Up, class _Vp _LIBCPP_OPTIONAL_PACK(class... _Rest)>
+struct _LIBCPP_TEMPLATE_VIS
+    common_type<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)>
+    : __common_type_impl<
+          __common_types<_Tp, _Up, _Vp _LIBCPP_OPTIONAL_PACK(_Rest...)> > {};
+
+#undef _LIBCPP_OPTIONAL_PACK
+
+#if _LIBCPP_STD_VER > 11
+template <class ..._Tp> using common_type_t = typename common_type<_Tp...>::type;
+#endif
+
+#if _LIBCPP_STD_VER > 11
+// Let COPYCV(FROM, TO) be an alias for type TO with the addition of FROM's
+// top-level cv-qualifiers.
+template <class _From, class _To>
+struct __copy_cv
+{
+    using type = _To;
+};
+
+template <class _From, class _To>
+struct __copy_cv<const _From, _To>
+{
+    using type = add_const_t<_To>;
+};
+
+template <class _From, class _To>
+struct __copy_cv<volatile _From, _To>
+{
+    using type = add_volatile_t<_To>;
+};
+
+template <class _From, class _To>
+struct __copy_cv<const volatile _From, _To>
+{
+    using type = add_cv_t<_To>;
+};
+
+template <class _From, class _To>
+using __copy_cv_t = typename __copy_cv<_From, _To>::type;
+
+template <class _From, class _To>
+struct __copy_cvref
+{
+    using type = __copy_cv_t<_From, _To>;
+};
+
+template <class _From, class _To>
+struct __copy_cvref<_From&, _To>
+{
+    using type = add_lvalue_reference_t<__copy_cv_t<_From, _To>>;
+};
+
+template <class _From, class _To>
+struct __copy_cvref<_From&&, _To>
+{
+    using type = add_rvalue_reference_t<__copy_cv_t<_From, _To>>;
+};
+
+template <class _From, class _To>
+using __copy_cvref_t = typename __copy_cvref<_From, _To>::type;
+
+#endif // _LIBCPP_STD_VER > 11
+
+// common_reference
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+// Let COND_RES(X, Y) be:
+template <class _Xp, class _Yp>
+using __cond_res =
+    decltype(false ? declval<_Xp(&)()>()() : declval<_Yp(&)()>()());
+
+// Let `XREF(A)` denote a unary alias template `T` such that `T<U>` denotes the same type as `U`
+// with the addition of `A`'s cv and reference qualifiers, for a non-reference cv-unqualified type
+// `U`.
+// [Note: `XREF(A)` is `__xref<A>::template __apply`]
+template <class _Tp>
+struct __xref {
+  template<class _Up>
+  using __apply = __copy_cvref_t<_Tp, _Up>;
+};
+
+// Given types A and B, let X be remove_reference_t<A>, let Y be remove_reference_t<B>,
+// and let COMMON-REF(A, B) be:
+template<class _Ap, class _Bp, class _Xp = remove_reference_t<_Ap>, class _Yp = remove_reference_t<_Bp>>
+struct __common_ref;
+
+template<class _Xp, class _Yp>
+using __common_ref_t = typename __common_ref<_Xp, _Yp>::__type;
+
+template<class _Xp, class _Yp>
+using __cv_cond_res = __cond_res<__copy_cv_t<_Xp, _Yp>&, __copy_cv_t<_Yp, _Xp>&>;
+
+
+//    If A and B are both lvalue reference types, COMMON-REF(A, B) is
+//    COND-RES(COPYCV(X, Y)&, COPYCV(Y, X)&) if that type exists and is a reference type.
+template<class _Ap, class _Bp, class _Xp, class _Yp>
+requires requires { typename __cv_cond_res<_Xp, _Yp>; } && is_reference_v<__cv_cond_res<_Xp, _Yp>>
+struct __common_ref<_Ap&, _Bp&, _Xp, _Yp>
+{
+    using __type = __cv_cond_res<_Xp, _Yp>;
+};
+
+//    Otherwise, let C be remove_reference_t<COMMON-REF(X&, Y&)>&&. ...
+template <class _Xp, class _Yp>
+using __common_ref_C = remove_reference_t<__common_ref_t<_Xp&, _Yp&>>&&;
+
+
+//    .... If A and B are both rvalue reference types, C is well-formed, and
+//    is_convertible_v<A, C> && is_convertible_v<B, C> is true, then COMMON-REF(A, B) is C.
+template<class _Ap, class _Bp, class _Xp, class _Yp>
+requires
+  requires { typename __common_ref_C<_Xp, _Yp>; } &&
+  is_convertible_v<_Ap&&, __common_ref_C<_Xp, _Yp>> &&
+  is_convertible_v<_Bp&&, __common_ref_C<_Xp, _Yp>>
+struct __common_ref<_Ap&&, _Bp&&, _Xp, _Yp>
+{
+    using __type = __common_ref_C<_Xp, _Yp>;
+};
+
+//    Otherwise, let D be COMMON-REF(const X&, Y&). ...
+template <class _Tp, class _Up>
+using __common_ref_D = __common_ref_t<const _Tp&, _Up&>;
+
+//    ... If A is an rvalue reference and B is an lvalue reference and D is well-formed and
+//    is_convertible_v<A, D> is true, then COMMON-REF(A, B) is D.
+template<class _Ap, class _Bp, class _Xp, class _Yp>
+requires requires { typename __common_ref_D<_Xp, _Yp>; } &&
+         is_convertible_v<_Ap&&, __common_ref_D<_Xp, _Yp>>
+struct __common_ref<_Ap&&, _Bp&, _Xp, _Yp>
+{
+    using __type = __common_ref_D<_Xp, _Yp>;
+};
+
+//    Otherwise, if A is an lvalue reference and B is an rvalue reference, then
+//    COMMON-REF(A, B) is COMMON-REF(B, A).
+template<class _Ap, class _Bp, class _Xp, class _Yp>
+struct __common_ref<_Ap&, _Bp&&, _Xp, _Yp> : __common_ref<_Bp&&, _Ap&> {};
+
+//    Otherwise, COMMON-REF(A, B) is ill-formed.
+template<class _Ap, class _Bp, class _Xp, class _Yp>
+struct __common_ref {};
+
+// Note C: For the common_reference trait applied to a parameter pack [...]
+
+template <class...>
+struct common_reference;
+
+template <class... _Types>
+using common_reference_t = typename common_reference<_Types...>::type;
+
+// bullet 1 - sizeof...(T) == 0
+template<>
+struct common_reference<> {};
+
+// bullet 2 - sizeof...(T) == 1
+template <class _Tp>
+struct common_reference<_Tp>
+{
+    using type = _Tp;
+};
+
+// bullet 3 - sizeof...(T) == 2
+template <class _Tp, class _Up> struct __common_reference_sub_bullet3;
+template <class _Tp, class _Up> struct __common_reference_sub_bullet2 : __common_reference_sub_bullet3<_Tp, _Up> {};
+template <class _Tp, class _Up> struct __common_reference_sub_bullet1 : __common_reference_sub_bullet2<_Tp, _Up> {};
+
+// sub-bullet 1 - If T1 and T2 are reference types and COMMON-REF(T1, T2) is well-formed, then
+// the member typedef `type` denotes that type.
+template <class _Tp, class _Up> struct common_reference<_Tp, _Up> : __common_reference_sub_bullet1<_Tp, _Up> {};
+
+template <class _Tp, class _Up>
+requires is_reference_v<_Tp> && is_reference_v<_Up> && requires { typename __common_ref_t<_Tp, _Up>; }
+struct __common_reference_sub_bullet1<_Tp, _Up>
+{
+    using type = __common_ref_t<_Tp, _Up>;
+};
+
+// sub-bullet 2 - Otherwise, if basic_common_reference<remove_cvref_t<T1>, remove_cvref_t<T2>, XREF(T1), XREF(T2)>::type
+// is well-formed, then the member typedef `type` denotes that type.
+template <class, class, template <class> class, template <class> class> struct basic_common_reference {};
+
+template <class _Tp, class _Up>
+using __basic_common_reference_t = typename basic_common_reference<
+    remove_cvref_t<_Tp>, remove_cvref_t<_Up>,
+    __xref<_Tp>::template __apply, __xref<_Up>::template __apply>::type;
+
+template <class _Tp, class _Up>
+requires requires { typename __basic_common_reference_t<_Tp, _Up>; }
+struct __common_reference_sub_bullet2<_Tp, _Up>
+{
+    using type = __basic_common_reference_t<_Tp, _Up>;
+};
+
+// sub-bullet 3 - Otherwise, if COND-RES(T1, T2) is well-formed,
+// then the member typedef `type` denotes that type.
+template <class _Tp, class _Up>
+requires requires { typename __cond_res<_Tp, _Up>; }
+struct __common_reference_sub_bullet3<_Tp, _Up>
+{
+    using type = __cond_res<_Tp, _Up>;
+};
+
+
+// sub-bullet 4 & 5 - Otherwise, if common_type_t<T1, T2> is well-formed,
+//                    then the member typedef `type` denotes that type.
+//                  - Otherwise, there shall be no member `type`.
+template <class _Tp, class _Up> struct __common_reference_sub_bullet3 : common_type<_Tp, _Up> {};
+
+// bullet 4 - If there is such a type `C`, the member typedef type shall denote the same type, if
+//            any, as `common_reference_t<C, Rest...>`.
+template <class _Tp, class _Up, class _Vp, class... _Rest>
+requires requires { typename common_reference_t<_Tp, _Up>; }
+struct common_reference<_Tp, _Up, _Vp, _Rest...>
+    : common_reference<common_reference_t<_Tp, _Up>, _Vp, _Rest...>
+{};
+
+// bullet 5 - Otherwise, there shall be no member `type`.
+template <class...> struct common_reference {};
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_CONCEPTS)
+
+// is_assignable
+
+template<typename, typename _Tp> struct __select_2nd { typedef _LIBCPP_NODEBUG _Tp type; };
+
+#if __has_keyword(__is_assignable)
+
+template<class _Tp, class _Up>
+struct _LIBCPP_TEMPLATE_VIS is_assignable : _BoolConstant<__is_assignable(_Tp, _Up)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, class _Arg>
+inline constexpr bool is_assignable_v = __is_assignable(_Tp, _Arg);
+#endif
+
+#else // __has_keyword(__is_assignable)
+
+template <class _Tp, class _Arg>
+typename __select_2nd<decltype((declval<_Tp>() = declval<_Arg>())), true_type>::type
+__is_assignable_test(int);
+
+template <class, class>
+false_type __is_assignable_test(...);
+
+
+template <class _Tp, class _Arg, bool = is_void<_Tp>::value || is_void<_Arg>::value>
+struct __is_assignable_imp
+    : public decltype((_VSTD::__is_assignable_test<_Tp, _Arg>(0))) {};
+
+template <class _Tp, class _Arg>
+struct __is_assignable_imp<_Tp, _Arg, true>
+    : public false_type
+{
+};
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template <class _Tp, class _Arg>
+struct is_assignable
+    : public _VSTD::integral_constant<bool, __is_assignable(_Tp, _Arg)> {};
+#else
+template <class _Tp, class _Arg>
+struct is_assignable
+    : public __is_assignable_imp<_Tp, _Arg> {};
+#endif
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, class _Arg>
+inline constexpr bool is_assignable_v = is_assignable<_Tp, _Arg>::value;
+#endif
+
+#endif // __has_keyword(__is_assignable)
+
+// is_copy_assignable
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_copy_assignable
+    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
+                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_copy_assignable_v = is_copy_assignable<_Tp>::value;
+#endif
+
+// is_move_assignable
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_move_assignable
+    : public is_assignable<typename add_lvalue_reference<_Tp>::type,
+                           typename add_rvalue_reference<_Tp>::type> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_move_assignable_v = is_move_assignable<_Tp>::value;
+#endif
+
+// is_destructible
+
+#if __has_keyword(__is_destructible)
+
+template<class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_destructible : _BoolConstant<__is_destructible(_Tp)> { };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_destructible_v = __is_destructible(_Tp);
+#endif
+
+#else // __has_keyword(__is_destructible)
+
+//  if it's a reference, return true
+//  if it's a function, return false
+//  if it's   void,     return false
+//  if it's an array of unknown bound, return false
+//  Otherwise, return "declval<_Up&>().~_Up()" is well-formed
+//    where _Up is remove_all_extents<_Tp>::type
+
+#if defined(_LIBCPP_COMPILER_MSVC)
+
+template <typename _Tp>
+struct is_destructible : integral_constant<bool, __is_destructible(_Tp)> {};
+
+#else
+
+template <class>
+struct __is_destructible_apply { typedef int type; };
+
+template <typename _Tp>
+struct __is_destructor_wellformed {
+    template <typename _Tp1>
+    static char  __test (
+        typename __is_destructible_apply<decltype(declval<_Tp1&>().~_Tp1())>::type
+    );
+
+    template <typename _Tp1>
+    static __two __test (...);
+
+    static const bool value = sizeof(__test<_Tp>(12)) == sizeof(char);
+};
+
+template <class _Tp, bool>
+struct __destructible_imp;
+
+template <class _Tp>
+struct __destructible_imp<_Tp, false>
+   : public integral_constant<bool,
+        __is_destructor_wellformed<typename remove_all_extents<_Tp>::type>::value> {};
+
+template <class _Tp>
+struct __destructible_imp<_Tp, true>
+    : public true_type {};
+
+template <class _Tp, bool>
+struct __destructible_false;
+
+template <class _Tp>
+struct __destructible_false<_Tp, false> : public __destructible_imp<_Tp, is_reference<_Tp>::value> {};
+
+template <class _Tp>
+struct __destructible_false<_Tp, true> : public false_type {};
+
+template <class _Tp>
+struct is_destructible
+    : public __destructible_false<_Tp, is_function<_Tp>::value> {};
+
+template <class _Tp>
+struct is_destructible<_Tp[]>
+    : public false_type {};
+
+template <>
+struct is_destructible<void>
+    : public false_type {};
+
+#endif
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_destructible_v = is_destructible<_Tp>::value;
+#endif
+
+#endif // __has_keyword(__is_destructible)
+
+template <class _MP, bool _IsMemberFunctionPtr, bool _IsMemberObjectPtr>
+struct __member_pointer_traits_imp
+{
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...), true, false>
+{
+    typedef _Class _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...), true, false>
+{
+    typedef _Class _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param..., ...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const, true, false>
+{
+    typedef _Class const _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const, true, false>
+{
+    typedef _Class const _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param..., ...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile, true, false>
+{
+    typedef _Class volatile _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile, true, false>
+{
+    typedef _Class volatile _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param..., ...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile, true, false>
+{
+    typedef _Class const volatile _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile, true, false>
+{
+    typedef _Class const volatile _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param..., ...);
+};
+
+#if __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &, true, false>
+{
+    typedef _Class& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &, true, false>
+{
+    typedef _Class& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param..., ...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&, true, false>
+{
+    typedef _Class const& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&, true, false>
+{
+    typedef _Class const& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param..., ...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&, true, false>
+{
+    typedef _Class volatile& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&, true, false>
+{
+    typedef _Class volatile& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param..., ...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&, true, false>
+{
+    typedef _Class const volatile& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&, true, false>
+{
+    typedef _Class const volatile& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param..., ...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) &&, true, false>
+{
+    typedef _Class&& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) &&, true, false>
+{
+    typedef _Class&& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param..., ...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const&&, true, false>
+{
+    typedef _Class const&& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const&&, true, false>
+{
+    typedef _Class const&& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param..., ...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) volatile&&, true, false>
+{
+    typedef _Class volatile&& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) volatile&&, true, false>
+{
+    typedef _Class volatile&& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param..., ...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param...) const volatile&&, true, false>
+{
+    typedef _Class const volatile&& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param...);
+};
+
+template <class _Rp, class _Class, class ..._Param>
+struct __member_pointer_traits_imp<_Rp (_Class::*)(_Param..., ...) const volatile&&, true, false>
+{
+    typedef _Class const volatile&& _ClassType;
+    typedef _Rp _ReturnType;
+    typedef _Rp (_FnType) (_Param..., ...);
+};
+
+#endif // __has_feature(cxx_reference_qualified_functions) || defined(_LIBCPP_COMPILER_GCC)
+
+
+template <class _Rp, class _Class>
+struct __member_pointer_traits_imp<_Rp _Class::*, false, true>
+{
+    typedef _Class _ClassType;
+    typedef _Rp _ReturnType;
+};
+
+template <class _MP>
+struct __member_pointer_traits
+    : public __member_pointer_traits_imp<typename remove_cv<_MP>::type,
+                    is_member_function_pointer<_MP>::value,
+                    is_member_object_pointer<_MP>::value>
+{
+//     typedef ... _ClassType;
+//     typedef ... _ReturnType;
+//     typedef ... _FnType;
+};
+
+
+template <class _DecayedFp>
+struct __member_pointer_class_type {};
+
+template <class _Ret, class _ClassType>
+struct __member_pointer_class_type<_Ret _ClassType::*> {
+  typedef _ClassType type;
+};
+
+// template <class T, class... Args> struct is_constructible;
+
+template <class _Tp, class ..._Args>
+struct _LIBCPP_TEMPLATE_VIS is_constructible
+    : public integral_constant<bool, __is_constructible(_Tp, _Args...)>
+{ };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, class ..._Args>
+inline constexpr bool is_constructible_v = is_constructible<_Tp, _Args...>::value;
+#endif
+
+// is_default_constructible
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_default_constructible
+    : public is_constructible<_Tp>
+    {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_default_constructible_v = is_default_constructible<_Tp>::value;
+#endif
+
+#ifndef _LIBCPP_CXX03_LANG
+// First of all, we can't implement this check in C++03 mode because the {}
+// default initialization syntax isn't valid.
+// Second, we implement the trait in a funny manner with two defaulted template
+// arguments to workaround Clang's PR43454.
+template <class _Tp>
+void __test_implicit_default_constructible(_Tp);
+
+template <class _Tp, class = void, class = typename is_default_constructible<_Tp>::type>
+struct __is_implicitly_default_constructible
+    : false_type
+{ };
+
+template <class _Tp>
+struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), true_type>
+    : true_type
+{ };
+
+template <class _Tp>
+struct __is_implicitly_default_constructible<_Tp, decltype(__test_implicit_default_constructible<_Tp const&>({})), false_type>
+    : false_type
+{ };
+#endif // !C++03
+
+// is_copy_constructible
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_copy_constructible
+    : public is_constructible<_Tp,
+                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_copy_constructible_v = is_copy_constructible<_Tp>::value;
+#endif
+
+// is_move_constructible
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_move_constructible
+    : public is_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
+    {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_move_constructible_v = is_move_constructible<_Tp>::value;
+#endif
+
+// is_trivially_constructible
+
+template <class _Tp, class... _Args>
+struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible
+    : integral_constant<bool, __is_trivially_constructible(_Tp, _Args...)>
+{
+};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, class... _Args>
+inline constexpr bool is_trivially_constructible_v = is_trivially_constructible<_Tp, _Args...>::value;
+#endif
+
+// is_trivially_default_constructible
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_default_constructible
+    : public is_trivially_constructible<_Tp>
+    {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_trivially_default_constructible_v = is_trivially_default_constructible<_Tp>::value;
+#endif
+
+// is_trivially_copy_constructible
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_constructible
+    : public is_trivially_constructible<_Tp, typename add_lvalue_reference<const _Tp>::type>
+    {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_trivially_copy_constructible_v = is_trivially_copy_constructible<_Tp>::value;
+#endif
+
+// is_trivially_move_constructible
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_constructible
+    : public is_trivially_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
+    {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_trivially_move_constructible_v = is_trivially_move_constructible<_Tp>::value;
+#endif
+
+// is_trivially_assignable
+
+template <class _Tp, class _Arg>
+struct is_trivially_assignable
+    : integral_constant<bool, __is_trivially_assignable(_Tp, _Arg)>
+{ };
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, class _Arg>
+inline constexpr bool is_trivially_assignable_v = is_trivially_assignable<_Tp, _Arg>::value;
+#endif
+
+// is_trivially_copy_assignable
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copy_assignable
+    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
+                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_trivially_copy_assignable_v = is_trivially_copy_assignable<_Tp>::value;
+#endif
+
+// is_trivially_move_assignable
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_move_assignable
+    : public is_trivially_assignable<typename add_lvalue_reference<_Tp>::type,
+                                     typename add_rvalue_reference<_Tp>::type>
+    {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_trivially_move_assignable_v = is_trivially_move_assignable<_Tp>::value;
+#endif
+
+// is_trivially_destructible
+
+#if __has_keyword(__is_trivially_destructible)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
+    : public integral_constant<bool, __is_trivially_destructible(_Tp)> {};
+
+#elif __has_feature(has_trivial_destructor) || defined(_LIBCPP_COMPILER_GCC)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
+    : public integral_constant<bool, is_destructible<_Tp>::value && __has_trivial_destructor(_Tp)> {};
+
+#else
+
+template <class _Tp> struct __libcpp_trivial_destructor
+    : public integral_constant<bool, is_scalar<_Tp>::value ||
+                                     is_reference<_Tp>::value> {};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible
+    : public __libcpp_trivial_destructor<typename remove_all_extents<_Tp>::type> {};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_destructible<_Tp[]>
+    : public false_type {};
+
+#endif
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_trivially_destructible_v = is_trivially_destructible<_Tp>::value;
+#endif
+
+// is_nothrow_constructible
+
+#if __has_keyword(__is_nothrow_constructible)
+
+template <class _Tp, class... _Args>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
+    : public integral_constant<bool, __is_nothrow_constructible(_Tp, _Args...)> {};
+
+#else
+
+template <bool, bool, class _Tp, class... _Args> struct __libcpp_is_nothrow_constructible;
+
+template <class _Tp, class... _Args>
+struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/false, _Tp, _Args...>
+    : public integral_constant<bool, noexcept(_Tp(declval<_Args>()...))>
+{
+};
+
+template <class _Tp>
+void __implicit_conversion_to(_Tp) noexcept { }
+
+template <class _Tp, class _Arg>
+struct __libcpp_is_nothrow_constructible</*is constructible*/true, /*is reference*/true, _Tp, _Arg>
+    : public integral_constant<bool, noexcept(_VSTD::__implicit_conversion_to<_Tp>(declval<_Arg>()))>
+{
+};
+
+template <class _Tp, bool _IsReference, class... _Args>
+struct __libcpp_is_nothrow_constructible</*is constructible*/false, _IsReference, _Tp, _Args...>
+    : public false_type
+{
+};
+
+template <class _Tp, class... _Args>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible
+    : __libcpp_is_nothrow_constructible<is_constructible<_Tp, _Args...>::value, is_reference<_Tp>::value, _Tp, _Args...>
+{
+};
+
+template <class _Tp, size_t _Ns>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_constructible<_Tp[_Ns]>
+    : __libcpp_is_nothrow_constructible<is_constructible<_Tp>::value, is_reference<_Tp>::value, _Tp>
+{
+};
+
+#endif // _LIBCPP_HAS_NO_NOEXCEPT
+
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, class ..._Args>
+inline constexpr bool is_nothrow_constructible_v = is_nothrow_constructible<_Tp, _Args...>::value;
+#endif
+
+// is_nothrow_default_constructible
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_default_constructible
+    : public is_nothrow_constructible<_Tp>
+    {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_nothrow_default_constructible_v = is_nothrow_default_constructible<_Tp>::value;
+#endif
+
+// is_nothrow_copy_constructible
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_constructible
+    : public is_nothrow_constructible<_Tp,
+                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_nothrow_copy_constructible_v = is_nothrow_copy_constructible<_Tp>::value;
+#endif
+
+// is_nothrow_move_constructible
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_constructible
+    : public is_nothrow_constructible<_Tp, typename add_rvalue_reference<_Tp>::type>
+    {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_nothrow_move_constructible_v = is_nothrow_move_constructible<_Tp>::value;
+#endif
+
+// is_nothrow_assignable
+
+#if __has_keyword(__is_nothrow_assignable)
+
+template <class _Tp, class _Arg>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
+    : public integral_constant<bool, __is_nothrow_assignable(_Tp, _Arg)> {};
+
+#else
+
+template <bool, class _Tp, class _Arg> struct __libcpp_is_nothrow_assignable;
+
+template <class _Tp, class _Arg>
+struct __libcpp_is_nothrow_assignable<false, _Tp, _Arg>
+    : public false_type
+{
+};
+
+template <class _Tp, class _Arg>
+struct __libcpp_is_nothrow_assignable<true, _Tp, _Arg>
+    : public integral_constant<bool, noexcept(declval<_Tp>() = declval<_Arg>()) >
+{
+};
+
+template <class _Tp, class _Arg>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_assignable
+    : public __libcpp_is_nothrow_assignable<is_assignable<_Tp, _Arg>::value, _Tp, _Arg>
+{
+};
+
+#endif // _LIBCPP_HAS_NO_NOEXCEPT
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp, class _Arg>
+inline constexpr bool is_nothrow_assignable_v = is_nothrow_assignable<_Tp, _Arg>::value;
+#endif
+
+// is_nothrow_copy_assignable
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_copy_assignable
+    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
+                  typename add_lvalue_reference<typename add_const<_Tp>::type>::type> {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_nothrow_copy_assignable_v = is_nothrow_copy_assignable<_Tp>::value;
+#endif
+
+// is_nothrow_move_assignable
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_move_assignable
+    : public is_nothrow_assignable<typename add_lvalue_reference<_Tp>::type,
+                                     typename add_rvalue_reference<_Tp>::type>
+    {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_nothrow_move_assignable_v = is_nothrow_move_assignable<_Tp>::value;
+#endif
+
+// is_nothrow_destructible
+
+#if !defined(_LIBCPP_CXX03_LANG)
+
+template <bool, class _Tp> struct __libcpp_is_nothrow_destructible;
+
+template <class _Tp>
+struct __libcpp_is_nothrow_destructible<false, _Tp>
+    : public false_type
+{
+};
+
+template <class _Tp>
+struct __libcpp_is_nothrow_destructible<true, _Tp>
+    : public integral_constant<bool, noexcept(declval<_Tp>().~_Tp()) >
+{
+};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
+    : public __libcpp_is_nothrow_destructible<is_destructible<_Tp>::value, _Tp>
+{
+};
+
+template <class _Tp, size_t _Ns>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[_Ns]>
+    : public is_nothrow_destructible<_Tp>
+{
+};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&>
+    : public true_type
+{
+};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp&&>
+    : public true_type
+{
+};
+
+#else
+
+template <class _Tp> struct __libcpp_nothrow_destructor
+    : public integral_constant<bool, is_scalar<_Tp>::value ||
+                                     is_reference<_Tp>::value> {};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible
+    : public __libcpp_nothrow_destructor<typename remove_all_extents<_Tp>::type> {};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_destructible<_Tp[]>
+    : public false_type {};
+
+#endif
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_nothrow_destructible_v = is_nothrow_destructible<_Tp>::value;
+#endif
+
+// is_pod
+
+#if __has_feature(is_pod) || defined(_LIBCPP_COMPILER_GCC)
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
+    : public integral_constant<bool, __is_pod(_Tp)> {};
+
+#else
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_pod
+    : public integral_constant<bool, is_trivially_default_constructible<_Tp>::value   &&
+                                     is_trivially_copy_constructible<_Tp>::value      &&
+                                     is_trivially_copy_assignable<_Tp>::value    &&
+                                     is_trivially_destructible<_Tp>::value> {};
+
+#endif
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_pod_v = is_pod<_Tp>::value;
+#endif
+
+// is_literal_type;
+
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS _LIBCPP_DEPRECATED_IN_CXX17 is_literal_type
+    : public integral_constant<bool, __is_literal_type(_Tp)>
+    {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+_LIBCPP_DEPRECATED_IN_CXX17 inline constexpr bool is_literal_type_v = is_literal_type<_Tp>::value;
+#endif // _LIBCPP_STD_VER > 14
+#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
+
+// is_standard_layout;
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_standard_layout
+#if __has_feature(is_standard_layout) || defined(_LIBCPP_COMPILER_GCC)
+    : public integral_constant<bool, __is_standard_layout(_Tp)>
+#else
+    : integral_constant<bool, is_scalar<typename remove_all_extents<_Tp>::type>::value>
+#endif
+    {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_standard_layout_v = is_standard_layout<_Tp>::value;
+#endif
+
+// is_trivially_copyable;
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivially_copyable
+    : public integral_constant<bool, __is_trivially_copyable(_Tp)>
+    {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_trivially_copyable_v = is_trivially_copyable<_Tp>::value;
+#endif
+
+// is_trivial;
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS is_trivial
+#if __has_feature(is_trivial) || defined(_LIBCPP_COMPILER_GCC)
+    : public integral_constant<bool, __is_trivial(_Tp)>
+#else
+    : integral_constant<bool, is_trivially_copyable<_Tp>::value &&
+                                 is_trivially_default_constructible<_Tp>::value>
+#endif
+    {};
+
+#if _LIBCPP_STD_VER > 14
+template <class _Tp>
+inline constexpr bool is_trivial_v = is_trivial<_Tp>::value;
+#endif
+
+template <class _Tp> struct __is_reference_wrapper_impl : public false_type {};
+template <class _Tp> struct __is_reference_wrapper_impl<reference_wrapper<_Tp> > : public true_type {};
+template <class _Tp> struct __is_reference_wrapper
+    : public __is_reference_wrapper_impl<typename remove_cv<_Tp>::type> {};
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Fp, class _A0,
+         class _DecayFp = typename decay<_Fp>::type,
+         class _DecayA0 = typename decay<_A0>::type,
+         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
+using __enable_if_bullet1 = typename enable_if
+    <
+        is_member_function_pointer<_DecayFp>::value
+        && is_base_of<_ClassT, _DecayA0>::value
+    >::type;
+
+template <class _Fp, class _A0,
+         class _DecayFp = typename decay<_Fp>::type,
+         class _DecayA0 = typename decay<_A0>::type>
+using __enable_if_bullet2 = typename enable_if
+    <
+        is_member_function_pointer<_DecayFp>::value
+        && __is_reference_wrapper<_DecayA0>::value
+    >::type;
+
+template <class _Fp, class _A0,
+         class _DecayFp = typename decay<_Fp>::type,
+         class _DecayA0 = typename decay<_A0>::type,
+         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
+using __enable_if_bullet3 = typename enable_if
+    <
+        is_member_function_pointer<_DecayFp>::value
+        && !is_base_of<_ClassT, _DecayA0>::value
+        && !__is_reference_wrapper<_DecayA0>::value
+    >::type;
+
+template <class _Fp, class _A0,
+         class _DecayFp = typename decay<_Fp>::type,
+         class _DecayA0 = typename decay<_A0>::type,
+         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
+using __enable_if_bullet4 = typename enable_if
+    <
+        is_member_object_pointer<_DecayFp>::value
+        && is_base_of<_ClassT, _DecayA0>::value
+    >::type;
+
+template <class _Fp, class _A0,
+         class _DecayFp = typename decay<_Fp>::type,
+         class _DecayA0 = typename decay<_A0>::type>
+using __enable_if_bullet5 = typename enable_if
+    <
+        is_member_object_pointer<_DecayFp>::value
+        && __is_reference_wrapper<_DecayA0>::value
+    >::type;
+
+template <class _Fp, class _A0,
+         class _DecayFp = typename decay<_Fp>::type,
+         class _DecayA0 = typename decay<_A0>::type,
+         class _ClassT = typename __member_pointer_class_type<_DecayFp>::type>
+using __enable_if_bullet6 = typename enable_if
+    <
+        is_member_object_pointer<_DecayFp>::value
+        && !is_base_of<_ClassT, _DecayA0>::value
+        && !__is_reference_wrapper<_DecayA0>::value
+    >::type;
+
+// __invoke forward declarations
+
+// fall back - none of the bullets
+
+template <class ..._Args>
+auto __invoke(__any, _Args&& ...__args) -> __nat;
+
+template <class ..._Args>
+auto __invoke_constexpr(__any, _Args&& ...__args) -> __nat;
+
+// bullets 1, 2 and 3
+
+template <class _Fp, class _A0, class ..._Args,
+          class = __enable_if_bullet1<_Fp, _A0>>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
+__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
+    noexcept(noexcept((static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...)))
+    -> decltype(      (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...))
+    { return          (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...); }
+
+template <class _Fp, class _A0, class ..._Args,
+          class = __enable_if_bullet1<_Fp, _A0>>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR auto
+__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
+    noexcept(noexcept((static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...)))
+    -> decltype(      (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...))
+    { return          (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...); }
+
+template <class _Fp, class _A0, class ..._Args,
+          class = __enable_if_bullet2<_Fp, _A0>>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
+__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
+    noexcept(noexcept((__a0.get().*__f)(static_cast<_Args&&>(__args)...)))
+    -> decltype(      (__a0.get().*__f)(static_cast<_Args&&>(__args)...))
+    { return          (__a0.get().*__f)(static_cast<_Args&&>(__args)...); }
+
+template <class _Fp, class _A0, class ..._Args,
+          class = __enable_if_bullet2<_Fp, _A0>>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR auto
+__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
+    noexcept(noexcept((__a0.get().*__f)(static_cast<_Args&&>(__args)...)))
+    -> decltype(      (__a0.get().*__f)(static_cast<_Args&&>(__args)...))
+    { return          (__a0.get().*__f)(static_cast<_Args&&>(__args)...); }
+
+template <class _Fp, class _A0, class ..._Args,
+          class = __enable_if_bullet3<_Fp, _A0>>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
+__invoke(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
+    noexcept(noexcept(((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...)))
+    -> decltype(      ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...))
+    { return          ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...); }
+
+template <class _Fp, class _A0, class ..._Args,
+          class = __enable_if_bullet3<_Fp, _A0>>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR auto
+__invoke_constexpr(_Fp&& __f, _A0&& __a0, _Args&& ...__args)
+    noexcept(noexcept(((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...)))
+    -> decltype(      ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...))
+    { return          ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...); }
+
+// bullets 4, 5 and 6
+
+template <class _Fp, class _A0,
+          class = __enable_if_bullet4<_Fp, _A0>>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
+__invoke(_Fp&& __f, _A0&& __a0)
+    noexcept(noexcept(static_cast<_A0&&>(__a0).*__f))
+    -> decltype(      static_cast<_A0&&>(__a0).*__f)
+    { return          static_cast<_A0&&>(__a0).*__f; }
+
+template <class _Fp, class _A0,
+          class = __enable_if_bullet4<_Fp, _A0>>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR auto
+__invoke_constexpr(_Fp&& __f, _A0&& __a0)
+    noexcept(noexcept(static_cast<_A0&&>(__a0).*__f))
+    -> decltype(      static_cast<_A0&&>(__a0).*__f)
+    { return          static_cast<_A0&&>(__a0).*__f; }
+
+template <class _Fp, class _A0,
+          class = __enable_if_bullet5<_Fp, _A0>>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
+__invoke(_Fp&& __f, _A0&& __a0)
+    noexcept(noexcept(__a0.get().*__f))
+    -> decltype(      __a0.get().*__f)
+    { return          __a0.get().*__f; }
+
+template <class _Fp, class _A0,
+          class = __enable_if_bullet5<_Fp, _A0>>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR auto
+__invoke_constexpr(_Fp&& __f, _A0&& __a0)
+    noexcept(noexcept(__a0.get().*__f))
+    -> decltype(      __a0.get().*__f)
+    { return          __a0.get().*__f; }
+
+template <class _Fp, class _A0,
+          class = __enable_if_bullet6<_Fp, _A0>>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
+__invoke(_Fp&& __f, _A0&& __a0)
+    noexcept(noexcept((*static_cast<_A0&&>(__a0)).*__f))
+    -> decltype(      (*static_cast<_A0&&>(__a0)).*__f)
+    { return          (*static_cast<_A0&&>(__a0)).*__f; }
+
+template <class _Fp, class _A0,
+          class = __enable_if_bullet6<_Fp, _A0>>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR auto
+__invoke_constexpr(_Fp&& __f, _A0&& __a0)
+    noexcept(noexcept((*static_cast<_A0&&>(__a0)).*__f))
+    -> decltype(      (*static_cast<_A0&&>(__a0)).*__f)
+    { return          (*static_cast<_A0&&>(__a0)).*__f; }
+
+// bullet 7
+
+template <class _Fp, class ..._Args>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 auto
+__invoke(_Fp&& __f, _Args&& ...__args)
+    noexcept(noexcept(static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...)))
+    -> decltype(      static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...))
+    { return          static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...); }
+
+template <class _Fp, class ..._Args>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR auto
+__invoke_constexpr(_Fp&& __f, _Args&& ...__args)
+    noexcept(noexcept(static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...)))
+    -> decltype(      static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...))
+    { return          static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...); }
+
+// __invokable
+template <class _Ret, class _Fp, class ..._Args>
+struct __invokable_r
+{
+  template <class _XFp, class ..._XArgs>
+  static auto __try_call(int) -> decltype(
+    _VSTD::__invoke(declval<_XFp>(), declval<_XArgs>()...));
+  template <class _XFp, class ..._XArgs>
+  static __nat __try_call(...);
+
+  // FIXME: Check that _Ret, _Fp, and _Args... are all complete types, cv void,
+  // or incomplete array types as required by the standard.
+  using _Result = decltype(__try_call<_Fp, _Args...>(0));
+
+  using type =
+  typename conditional<
+      _IsNotSame<_Result, __nat>::value,
+      typename conditional<
+          is_void<_Ret>::value,
+          true_type,
+          is_convertible<_Result, _Ret>
+      >::type,
+      false_type
+  >::type;
+  static const bool value = type::value;
+};
+template <class _Fp, class ..._Args>
+using __invokable = __invokable_r<void, _Fp, _Args...>;
+
+template <bool _IsInvokable, bool _IsCVVoid, class _Ret, class _Fp, class ..._Args>
+struct __nothrow_invokable_r_imp {
+  static const bool value = false;
+};
+
+template <class _Ret, class _Fp, class ..._Args>
+struct __nothrow_invokable_r_imp<true, false, _Ret, _Fp, _Args...>
+{
+    typedef __nothrow_invokable_r_imp _ThisT;
+
+    template <class _Tp>
+    static void __test_noexcept(_Tp) noexcept;
+
+    static const bool value = noexcept(_ThisT::__test_noexcept<_Ret>(
+        _VSTD::__invoke(declval<_Fp>(), declval<_Args>()...)));
+};
+
+template <class _Ret, class _Fp, class ..._Args>
+struct __nothrow_invokable_r_imp<true, true, _Ret, _Fp, _Args...>
+{
+    static const bool value = noexcept(
+        _VSTD::__invoke(declval<_Fp>(), declval<_Args>()...));
+};
+
+template <class _Ret, class _Fp, class ..._Args>
+using __nothrow_invokable_r =
+    __nothrow_invokable_r_imp<
+            __invokable_r<_Ret, _Fp, _Args...>::value,
+            is_void<_Ret>::value,
+            _Ret, _Fp, _Args...
+    >;
+
+template <class _Fp, class ..._Args>
+using __nothrow_invokable =
+    __nothrow_invokable_r_imp<
+            __invokable<_Fp, _Args...>::value,
+            true, void, _Fp, _Args...
+    >;
+
+template <class _Fp, class ..._Args>
+struct __invoke_of
+    : public enable_if<
+        __invokable<_Fp, _Args...>::value,
+        typename __invokable_r<void, _Fp, _Args...>::_Result>
+{
+};
+
+#endif // _LIBCPP_CXX03_LANG
+
+// result_of
+
+#if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
+template <class _Callable> class _LIBCPP_DEPRECATED_IN_CXX17 result_of;
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Fp, class ..._Args>
+class _LIBCPP_TEMPLATE_VIS result_of<_Fp(_Args...)>
+    : public __invoke_of<_Fp, _Args...>
+{
+};
+
+#else // C++03
+
+template <class _Fn, bool, bool>
+class __result_of
+{
+};
+
+template <class _Fn, class ..._Args>
+class __result_of<_Fn(_Args...), true, false>
+{
+public:
+    typedef decltype(declval<_Fn>()(declval<_Args>()...)) type;
+};
+
+template <class _MP, class _Tp, bool _IsMemberFunctionPtr>
+struct __result_of_mp;
+
+// member function pointer
+
+template <class _MP, class _Tp>
+struct __result_of_mp<_MP, _Tp, true>
+{
+    using type = typename __member_pointer_traits<_MP>::_ReturnType;
+};
+
+// member data pointer
+
+template <class _MP, class _Tp, bool>
+struct __result_of_mdp;
+
+template <class _Rp, class _Class, class _Tp>
+struct __result_of_mdp<_Rp _Class::*, _Tp, false>
+{
+    using type = typename __apply_cv<decltype(*declval<_Tp>()), _Rp>::type&;
+};
+
+template <class _Rp, class _Class, class _Tp>
+struct __result_of_mdp<_Rp _Class::*, _Tp, true>
+{
+    using type = typename __apply_cv<_Tp, _Rp>::type&;
+};
+
+template <class _Rp, class _Class, class _Tp>
+struct __result_of_mp<_Rp _Class::*, _Tp, false>
+    : public __result_of_mdp<_Rp _Class::*, _Tp,
+            is_base_of<_Class, typename remove_reference<_Tp>::type>::value>
+{
+};
+
+template <class _Fn, class _Tp>
+class __result_of<_Fn(_Tp), false, true>  // _Fn must be member pointer
+    : public __result_of_mp<typename remove_reference<_Fn>::type,
+                            _Tp,
+                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
+{
+};
+
+template <class _Fn, class _Tp, class ..._Args>
+class __result_of<_Fn(_Tp, _Args...), false, true>  // _Fn must be member pointer
+    : public __result_of_mp<typename remove_reference<_Fn>::type,
+                            _Tp,
+                            is_member_function_pointer<typename remove_reference<_Fn>::type>::value>
+{
+};
+
+template <class _Fn, class ..._Args>
+class _LIBCPP_TEMPLATE_VIS result_of<_Fn(_Args...)>
+    : public __result_of<_Fn(_Args...),
+                         is_class<typename remove_reference<_Fn>::type>::value ||
+                         is_function<typename remove_pointer<typename remove_reference<_Fn>::type>::type>::value,
+                         is_member_pointer<typename remove_reference<_Fn>::type>::value
+                        >
+{
+};
+
+#endif // C++03
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using result_of_t _LIBCPP_DEPRECATED_IN_CXX17 = typename result_of<_Tp>::type;
+#endif // _LIBCPP_STD_VER > 11
+#endif // _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_TYPE_TRAITS)
+
+#if _LIBCPP_STD_VER > 14
+
+// invoke_result
+
+template <class _Fn, class... _Args>
+struct _LIBCPP_TEMPLATE_VIS invoke_result
+    : __invoke_of<_Fn, _Args...>
+{
+};
+
+template <class _Fn, class... _Args>
+using invoke_result_t = typename invoke_result<_Fn, _Args...>::type;
+
+// is_invocable
+
+template <class _Fn, class ..._Args>
+struct _LIBCPP_TEMPLATE_VIS is_invocable
+    : integral_constant<bool, __invokable<_Fn, _Args...>::value> {};
+
+template <class _Ret, class _Fn, class ..._Args>
+struct _LIBCPP_TEMPLATE_VIS is_invocable_r
+    : integral_constant<bool, __invokable_r<_Ret, _Fn, _Args...>::value> {};
+
+template <class _Fn, class ..._Args>
+inline constexpr bool is_invocable_v = is_invocable<_Fn, _Args...>::value;
+
+template <class _Ret, class _Fn, class ..._Args>
+inline constexpr bool is_invocable_r_v = is_invocable_r<_Ret, _Fn, _Args...>::value;
+
+// is_nothrow_invocable
+
+template <class _Fn, class ..._Args>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable
+    : integral_constant<bool, __nothrow_invokable<_Fn, _Args...>::value> {};
+
+template <class _Ret, class _Fn, class ..._Args>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_invocable_r
+    : integral_constant<bool, __nothrow_invokable_r<_Ret, _Fn, _Args...>::value> {};
+
+template <class _Fn, class ..._Args>
+inline constexpr bool is_nothrow_invocable_v = is_nothrow_invocable<_Fn, _Args...>::value;
+
+template <class _Ret, class _Fn, class ..._Args>
+inline constexpr bool is_nothrow_invocable_r_v = is_nothrow_invocable_r<_Ret, _Fn, _Args...>::value;
+
+#endif // _LIBCPP_STD_VER > 14
+
+// __swappable
+
+template <class _Tp> struct __is_swappable;
+template <class _Tp> struct __is_nothrow_swappable;
+
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp>
+using __swap_result_t = typename enable_if<is_move_constructible<_Tp>::value && is_move_assignable<_Tp>::value>::type;
+#else
+template <class>
+using __swap_result_t = void;
+#endif
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_CONSTEXPR_AFTER_CXX17 __swap_result_t<_Tp>
+swap(_Tp& __x, _Tp& __y) _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value &&
+                                    is_nothrow_move_assignable<_Tp>::value);
+
+template<class _Tp, size_t _Np>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+typename enable_if<
+    __is_swappable<_Tp>::value
+>::type
+swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value);
+
+namespace __detail
+{
+// ALL generic swap overloads MUST already have a declaration available at this point.
+
+template <class _Tp, class _Up = _Tp,
+          bool _NotVoid = !is_void<_Tp>::value && !is_void<_Up>::value>
+struct __swappable_with
+{
+    template <class _LHS, class _RHS>
+    static decltype(swap(declval<_LHS>(), declval<_RHS>()))
+    __test_swap(int);
+    template <class, class>
+    static __nat __test_swap(long);
+
+    // Extra parens are needed for the C++03 definition of decltype.
+    typedef decltype((__test_swap<_Tp, _Up>(0))) __swap1;
+    typedef decltype((__test_swap<_Up, _Tp>(0))) __swap2;
+
+    static const bool value = _IsNotSame<__swap1, __nat>::value
+                           && _IsNotSame<__swap2, __nat>::value;
+};
+
+template <class _Tp, class _Up>
+struct __swappable_with<_Tp, _Up,  false> : false_type {};
+
+template <class _Tp, class _Up = _Tp, bool _Swappable = __swappable_with<_Tp, _Up>::value>
+struct __nothrow_swappable_with {
+  static const bool value =
+#ifndef _LIBCPP_HAS_NO_NOEXCEPT
+      noexcept(swap(declval<_Tp>(), declval<_Up>()))
+  &&  noexcept(swap(declval<_Up>(), declval<_Tp>()));
+#else
+      false;
+#endif
+};
+
+template <class _Tp, class _Up>
+struct __nothrow_swappable_with<_Tp, _Up, false> : false_type {};
+
+}  // __detail
+
+template <class _Tp>
+struct __is_swappable
+    : public integral_constant<bool, __detail::__swappable_with<_Tp&>::value>
+{
+};
+
+template <class _Tp>
+struct __is_nothrow_swappable
+    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp&>::value>
+{
+};
+
+#if _LIBCPP_STD_VER > 14
+
+template <class _Tp, class _Up>
+struct _LIBCPP_TEMPLATE_VIS is_swappable_with
+    : public integral_constant<bool, __detail::__swappable_with<_Tp, _Up>::value>
+{
+};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_swappable
+    : public conditional<
+        __is_referenceable<_Tp>::value,
+        is_swappable_with<
+            typename add_lvalue_reference<_Tp>::type,
+            typename add_lvalue_reference<_Tp>::type>,
+        false_type
+    >::type
+{
+};
+
+template <class _Tp, class _Up>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable_with
+    : public integral_constant<bool, __detail::__nothrow_swappable_with<_Tp, _Up>::value>
+{
+};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_nothrow_swappable
+    : public conditional<
+        __is_referenceable<_Tp>::value,
+        is_nothrow_swappable_with<
+            typename add_lvalue_reference<_Tp>::type,
+            typename add_lvalue_reference<_Tp>::type>,
+        false_type
+    >::type
+{
+};
+
+template <class _Tp, class _Up>
+inline constexpr bool is_swappable_with_v = is_swappable_with<_Tp, _Up>::value;
+
+template <class _Tp>
+inline constexpr bool is_swappable_v = is_swappable<_Tp>::value;
+
+template <class _Tp, class _Up>
+inline constexpr bool is_nothrow_swappable_with_v = is_nothrow_swappable_with<_Tp, _Up>::value;
+
+template <class _Tp>
+inline constexpr bool is_nothrow_swappable_v = is_nothrow_swappable<_Tp>::value;
+
+#endif // _LIBCPP_STD_VER > 14
+
+template <class _Tp, bool = is_enum<_Tp>::value> struct __underlying_type_impl;
+
+template <class _Tp>
+struct __underlying_type_impl<_Tp, false> {};
+
+template <class _Tp>
+struct __underlying_type_impl<_Tp, true>
+{
+    typedef __underlying_type(_Tp) type;
+};
+
+template <class _Tp>
+struct underlying_type : __underlying_type_impl<_Tp, is_enum<_Tp>::value> {};
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp> using underlying_type_t = typename underlying_type<_Tp>::type;
+#endif
+
+template <class _Tp, bool = is_enum<_Tp>::value>
+struct __sfinae_underlying_type
+{
+    typedef typename underlying_type<_Tp>::type type;
+    typedef decltype(((type)1) + 0) __promoted_type;
+};
+
+template <class _Tp>
+struct __sfinae_underlying_type<_Tp, false> {};
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+int __convert_to_integral(int __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+unsigned __convert_to_integral(unsigned __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+long __convert_to_integral(long __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+unsigned long __convert_to_integral(unsigned long __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+long long __convert_to_integral(long long __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+unsigned long long __convert_to_integral(unsigned long long __val) {return __val; }
+
+template<typename _Fp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename enable_if<is_floating_point<_Fp>::value, long long>::type
+ __convert_to_integral(_Fp __val) { return __val; }
+
+#ifndef _LIBCPP_HAS_NO_INT128
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+__int128_t __convert_to_integral(__int128_t __val) { return __val; }
+
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+__uint128_t __convert_to_integral(__uint128_t __val) { return __val; }
+#endif
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename __sfinae_underlying_type<_Tp>::__promoted_type
+__convert_to_integral(_Tp __val) { return __val; }
+
+// is_scoped_enum [meta.unary.prop]
+
+#if _LIBCPP_STD_VER > 20
+template <class _Tp, bool = is_enum_v<_Tp> >
+struct __is_scoped_enum_helper : false_type {};
+
+template <class _Tp>
+struct __is_scoped_enum_helper<_Tp, true>
+    : public bool_constant<!is_convertible_v<_Tp, underlying_type_t<_Tp> > > {};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS is_scoped_enum
+    : public __is_scoped_enum_helper<_Tp> {};
+
+template <class _Tp>
+inline constexpr bool is_scoped_enum_v = is_scoped_enum<_Tp>::value;
+#endif
+
+#if _LIBCPP_STD_VER > 14
+
+template <class... _Args>
+struct conjunction : _And<_Args...> {};
+template<class... _Args>
+inline constexpr bool conjunction_v = conjunction<_Args...>::value;
+
+template <class... _Args>
+struct disjunction : _Or<_Args...> {};
+template<class... _Args>
+inline constexpr bool disjunction_v = disjunction<_Args...>::value;
+
+template <class _Tp>
+struct negation : _Not<_Tp> {};
+template<class _Tp>
+inline constexpr bool negation_v = negation<_Tp>::value;
+#endif // _LIBCPP_STD_VER > 14
+
+// These traits are used in __tree and __hash_table
+struct __extract_key_fail_tag {};
+struct __extract_key_self_tag {};
+struct __extract_key_first_tag {};
+
+template <class _ValTy, class _Key,
+          class _RawValTy = typename __unconstref<_ValTy>::type>
+struct __can_extract_key
+    : conditional<_IsSame<_RawValTy, _Key>::value, __extract_key_self_tag,
+                  __extract_key_fail_tag>::type {};
+
+template <class _Pair, class _Key, class _First, class _Second>
+struct __can_extract_key<_Pair, _Key, pair<_First, _Second> >
+    : conditional<_IsSame<typename remove_const<_First>::type, _Key>::value,
+                  __extract_key_first_tag, __extract_key_fail_tag>::type {};
+
+// __can_extract_map_key uses true_type/false_type instead of the tags.
+// It returns true if _Key != _ContainerValueTy (the container is a map not a set)
+// and _ValTy == _Key.
+template <class _ValTy, class _Key, class _ContainerValueTy,
+          class _RawValTy = typename __unconstref<_ValTy>::type>
+struct __can_extract_map_key
+    : integral_constant<bool, _IsSame<_RawValTy, _Key>::value> {};
+
+// This specialization returns __extract_key_fail_tag for non-map containers
+// because _Key == _ContainerValueTy
+template <class _ValTy, class _Key, class _RawValTy>
+struct __can_extract_map_key<_ValTy, _Key, _Key, _RawValTy>
+    : false_type {};
+
+#ifndef _LIBCPP_HAS_NO_BUILTIN_IS_CONSTANT_EVALUATED
+#if _LIBCPP_STD_VER > 17
+_LIBCPP_INLINE_VISIBILITY
+inline constexpr bool is_constant_evaluated() noexcept {
+  return __builtin_is_constant_evaluated();
+}
+#endif
+
+inline _LIBCPP_CONSTEXPR
+bool __libcpp_is_constant_evaluated() _NOEXCEPT { return __builtin_is_constant_evaluated(); }
+#else
+inline _LIBCPP_CONSTEXPR
+bool __libcpp_is_constant_evaluated() _NOEXCEPT { return false; }
+#endif
+
+template <class _CharT>
+using _IsCharLikeType = _And<is_standard_layout<_CharT>, is_trivial<_CharT> >;
+
+template<class _Tp>
+using __make_const_lvalue_ref = const typename remove_reference<_Tp>::type&;
+
+#if _LIBCPP_STD_VER > 17
+template<bool _Const, class _Tp>
+using __maybe_const = conditional_t<_Const, const _Tp, _Tp>;
+#endif // _LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning(pop)
+#endif
+
+#endif // _LIBCPP_TYPE_TRAITS
diff --git a/contrib/libs/cxxsupp/libcxx/include/typeindex b/contrib/libs/cxxsupp/libcxx/include/typeindex
new file mode 100644
index 00000000000..88bb9ef03d6
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/typeindex
@@ -0,0 +1,104 @@
+// -*- C++ -*-
+//===-------------------------- typeindex ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_TYPEINDEX
+#define _LIBCPP_TYPEINDEX
+
+/*
+
+    typeindex synopsis
+
+namespace std
+{
+
+class type_index
+{
+public:
+    type_index(const type_info& rhs) noexcept;
+
+    bool operator==(const type_index& rhs) const noexcept;
+    bool operator!=(const type_index& rhs) const noexcept;
+    bool operator< (const type_index& rhs) const noexcept;
+    bool operator<=(const type_index& rhs) const noexcept;
+    bool operator> (const type_index& rhs) const noexcept;
+    bool operator>=(const type_index& rhs) const noexcept;
+
+    size_t hash_code() const noexcept;
+    const char* name() const noexcept;
+};
+
+template <>
+struct hash<type_index>
+    : public unary_function<type_index, size_t>
+{
+    size_t operator()(type_index index) const noexcept;
+};
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__functional/unary_function.h>
+#include <__functional_base>
+#include <compare>
+#include <typeinfo>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+class _LIBCPP_TEMPLATE_VIS type_index
+{
+    const type_info* __t_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    type_index(const type_info& __y) _NOEXCEPT : __t_(&__y) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const type_index& __y) const _NOEXCEPT
+        {return *__t_ == *__y.__t_;}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const type_index& __y) const _NOEXCEPT
+        {return *__t_ != *__y.__t_;}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator< (const type_index& __y) const _NOEXCEPT
+        {return  __t_->before(*__y.__t_);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator<=(const type_index& __y) const _NOEXCEPT
+        {return !__y.__t_->before(*__t_);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator> (const type_index& __y) const _NOEXCEPT
+        {return  __y.__t_->before(*__t_);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator>=(const type_index& __y) const _NOEXCEPT
+        {return !__t_->before(*__y.__t_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t hash_code() const _NOEXCEPT {return __t_->hash_code();}
+    _LIBCPP_INLINE_VISIBILITY
+    const char* name() const _NOEXCEPT {return __t_->name();}
+};
+
+template <class _Tp> struct _LIBCPP_TEMPLATE_VIS hash;
+
+template <>
+struct _LIBCPP_TEMPLATE_VIS hash<type_index>
+    : public unary_function<type_index, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(type_index __index) const _NOEXCEPT
+        {return __index.hash_code();}
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_TYPEINDEX
diff --git a/contrib/libs/cxxsupp/libcxx/include/typeinfo b/contrib/libs/cxxsupp/libcxx/include/typeinfo
new file mode 100644
index 00000000000..80c938646b0
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/typeinfo
@@ -0,0 +1,402 @@
+// -*- C++ -*-
+//===-------------------------- typeinfo ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __LIBCPP_TYPEINFO
+#define __LIBCPP_TYPEINFO
+
+/*
+
+    typeinfo synopsis
+
+namespace std {
+
+class type_info
+{
+public:
+    virtual ~type_info();
+
+    bool operator==(const type_info& rhs) const noexcept;
+    bool operator!=(const type_info& rhs) const noexcept;
+
+    bool before(const type_info& rhs) const noexcept;
+    size_t hash_code() const noexcept;
+    const char* name() const noexcept;
+
+    type_info(const type_info& rhs) = delete;
+    type_info& operator=(const type_info& rhs) = delete;
+};
+
+class bad_cast
+    : public exception
+{
+public:
+    bad_cast() noexcept;
+    bad_cast(const bad_cast&) noexcept;
+    bad_cast& operator=(const bad_cast&) noexcept;
+    virtual const char* what() const noexcept;
+};
+
+class bad_typeid
+    : public exception
+{
+public:
+    bad_typeid() noexcept;
+    bad_typeid(const bad_typeid&) noexcept;
+    bad_typeid& operator=(const bad_typeid&) noexcept;
+    virtual const char* what() const noexcept;
+};
+
+}  // std
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <cstddef>
+#include <cstdint>
+#include <exception>
+#include <type_traits>
+
+#ifdef _LIBCPP_NO_EXCEPTIONS
+#include <cstdlib>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#if defined(_LIBCPP_ABI_VCRUNTIME)
+#include <vcruntime_typeinfo.h>
+#else
+
+namespace std  // purposefully not using versioning namespace
+{
+
+
+#if defined(_LIBCPP_ABI_MICROSOFT)
+
+class _LIBCPP_EXCEPTION_ABI type_info
+{
+    type_info& operator=(const type_info&);
+    type_info(const type_info&);
+
+    mutable struct {
+      const char *__undecorated_name;
+      const char __decorated_name[1];
+    } __data;
+
+    int __compare(const type_info &__rhs) const _NOEXCEPT;
+
+public:
+    _LIBCPP_AVAILABILITY_TYPEINFO_VTABLE
+    virtual ~type_info();
+
+    const char *name() const _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool before(const type_info& __arg) const _NOEXCEPT {
+      return __compare(__arg) < 0;
+    }
+
+    size_t hash_code() const _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const type_info& __arg) const _NOEXCEPT {
+      return __compare(__arg) == 0;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const type_info& __arg) const _NOEXCEPT
+    { return !operator==(__arg); }
+};
+
+#else // !defined(_LIBCPP_ABI_MICROSOFT)
+
+// ========================================================================== //
+//                           Implementations
+// ========================================================================== //
+// ------------------------------------------------------------------------- //
+//                               Unique
+//               (_LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION = 1)
+// ------------------------------------------------------------------------- //
+// This implementation of type_info assumes a unique copy of the RTTI for a
+// given type inside a program. This is a valid assumption when abiding to the
+// Itanium ABI (http://itanium-cxx-abi.github.io/cxx-abi/abi.html#vtable-components).
+// Under this assumption, we can always compare the addresses of the type names
+// to implement equality-comparison of type_infos instead of having to perform
+// a deep string comparison.
+// -------------------------------------------------------------------------- //
+//                             NonUnique
+//               (_LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION = 2)
+// -------------------------------------------------------------------------- //
+// This implementation of type_info does not assume there is always a unique
+// copy of the RTTI for a given type inside a program. For various reasons
+// the linker may have failed to merge every copy of a types RTTI
+// (For example: -Bsymbolic or llvm.org/PR37398). Under this assumption, two
+// type_infos are equal if their addresses are equal or if a deep string
+// comparison is equal.
+// -------------------------------------------------------------------------- //
+//                          NonUniqueARMRTTIBit
+//               (_LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION = 3)
+// -------------------------------------------------------------------------- //
+// This implementation is specific to ARM64 on Apple platforms.
+//
+// This implementation of type_info does not assume always a unique copy of
+// the RTTI for a given type inside a program. When constructing the type_info,
+// the compiler packs the pointer to the type name into a uintptr_t and reserves
+// the high bit of that pointer, which is assumed to be free for use under that
+// ABI. If that high bit is set, that specific copy of the RTTI can't be assumed
+// to be unique within the program. If the high bit is unset, then the RTTI can
+// be assumed to be unique within the program.
+//
+// When comparing type_infos, if both RTTIs can be assumed to be unique, it
+// suffices to compare their addresses. If both the RTTIs can't be assumed to
+// be unique, we must perform a deep string comparison of the type names.
+// However, if one of the RTTIs is guaranteed unique and the other one isn't,
+// then both RTTIs are necessarily not to be considered equal.
+//
+// The intent of this design is to remove the need for weak symbols. Specifically,
+// if a type would normally have a default-visibility RTTI emitted as a weak
+// symbol, it is given hidden visibility instead and the non-unique bit is set.
+// Otherwise, types declared with hidden visibility are always considered to have
+// a unique RTTI: the RTTI is emitted with linkonce_odr linkage and is assumed
+// to be deduplicated by the linker within the linked image. Across linked image
+// boundaries, such types are thus considered different types.
+
+// This value can be overriden in the __config_site. When it's not overriden,
+// we pick a default implementation based on the platform here.
+#ifndef _LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION
+
+  // Windows binaries can't merge typeinfos, so use the NonUnique implementation.
+# ifdef _LIBCPP_OBJECT_FORMAT_COFF
+#   define _LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION 2
+
+  // On arm64 on Apple platforms, use the special NonUniqueARMRTTIBit implementation.
+# elif defined(__APPLE__) && defined(__LP64__) && !defined(__x86_64__)
+#   define _LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION 3
+
+  // On all other platforms, assume the Itanium C++ ABI and use the Unique implementation.
+# else
+#   define _LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION 1
+# endif
+#endif
+
+struct __type_info_implementations {
+  struct __string_impl_base {
+    typedef const char* __type_name_t;
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+    _LIBCPP_CONSTEXPR static const char* __type_name_to_string(__type_name_t __v) _NOEXCEPT {
+      return __v;
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+    _LIBCPP_CONSTEXPR static __type_name_t __string_to_type_name(const char* __v) _NOEXCEPT {
+      return __v;
+    }
+  };
+
+  struct __unique_impl : __string_impl_base {
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+    static size_t __hash(__type_name_t __v) _NOEXCEPT {
+      return reinterpret_cast<size_t>(__v);
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+    static bool __eq(__type_name_t __lhs, __type_name_t __rhs) _NOEXCEPT {
+      return __lhs == __rhs;
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+    static bool __lt(__type_name_t __lhs, __type_name_t __rhs) _NOEXCEPT {
+      return __lhs < __rhs;
+    }
+  };
+
+  struct __non_unique_impl : __string_impl_base {
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+    static size_t __hash(__type_name_t __ptr) _NOEXCEPT {
+      size_t __hash = 5381;
+      while (unsigned char __c = static_cast<unsigned char>(*__ptr++))
+        __hash = (__hash * 33) ^ __c;
+      return __hash;
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+    static bool __eq(__type_name_t __lhs, __type_name_t __rhs) _NOEXCEPT {
+      return __lhs == __rhs || __builtin_strcmp(__lhs, __rhs) == 0;
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+    static bool __lt(__type_name_t __lhs, __type_name_t __rhs) _NOEXCEPT {
+      return __builtin_strcmp(__lhs, __rhs) < 0;
+    }
+  };
+
+  struct __non_unique_arm_rtti_bit_impl {
+    typedef uintptr_t __type_name_t;
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+    static const char* __type_name_to_string(__type_name_t __v) _NOEXCEPT {
+      return reinterpret_cast<const char*>(__v &
+          ~__non_unique_rtti_bit::value);
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+    static __type_name_t __string_to_type_name(const char* __v) _NOEXCEPT {
+      return reinterpret_cast<__type_name_t>(__v);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+    static size_t __hash(__type_name_t __v) _NOEXCEPT {
+      if (__is_type_name_unique(__v))
+        return __v;
+      return __non_unique_impl::__hash(__type_name_to_string(__v));
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+    static bool __eq(__type_name_t __lhs, __type_name_t __rhs) _NOEXCEPT {
+      if (__lhs == __rhs)
+        return true;
+      if (__is_type_name_unique(__lhs) || __is_type_name_unique(__rhs))
+        // Either both are unique and have a different address, or one of them
+        // is unique and the other one isn't. In both cases they are unequal.
+        return false;
+      return __builtin_strcmp(__type_name_to_string(__lhs), __type_name_to_string(__rhs)) == 0;
+    }
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_ALWAYS_INLINE
+    static bool __lt(__type_name_t __lhs, __type_name_t __rhs) _NOEXCEPT {
+      if (__is_type_name_unique(__lhs) || __is_type_name_unique(__rhs))
+        return __lhs < __rhs;
+      return __builtin_strcmp(__type_name_to_string(__lhs), __type_name_to_string(__rhs)) < 0;
+    }
+
+   private:
+    // The unique bit is the top bit. It is expected that __type_name_t is 64 bits when
+    // this implementation is actually used.
+    typedef integral_constant<__type_name_t,
+      (1ULL << ((__CHAR_BIT__ * sizeof(__type_name_t)) - 1))> __non_unique_rtti_bit;
+
+    _LIBCPP_INLINE_VISIBILITY
+    static bool __is_type_name_unique(__type_name_t __lhs) _NOEXCEPT {
+      return !(__lhs & __non_unique_rtti_bit::value);
+    }
+  };
+
+  typedef
+#if _LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION == 1
+    __unique_impl
+#elif _LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION == 2
+    __non_unique_impl
+#elif _LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION == 3
+    __non_unique_arm_rtti_bit_impl
+#else
+#   error invalid configuration for _LIBCPP_TYPEINFO_COMPARISON_IMPLEMENTATION
+#endif
+     __impl;
+};
+
+class _LIBCPP_EXCEPTION_ABI type_info
+{
+  type_info& operator=(const type_info&);
+  type_info(const type_info&);
+
+ protected:
+    typedef __type_info_implementations::__impl __impl;
+
+    __impl::__type_name_t __type_name;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit type_info(const char* __n)
+      : __type_name(__impl::__string_to_type_name(__n)) {}
+
+public:
+    _LIBCPP_AVAILABILITY_TYPEINFO_VTABLE
+    virtual ~type_info();
+
+    _LIBCPP_INLINE_VISIBILITY
+    const char* name() const _NOEXCEPT
+    {
+      return __impl::__type_name_to_string(__type_name);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool before(const type_info& __arg) const _NOEXCEPT
+    {
+      return __impl::__lt(__type_name, __arg.__type_name);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t hash_code() const _NOEXCEPT
+    {
+      return __impl::__hash(__type_name);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const type_info& __arg) const _NOEXCEPT
+    {
+      return __impl::__eq(__type_name, __arg.__type_name);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const type_info& __arg) const _NOEXCEPT
+    { return !operator==(__arg); }
+};
+#endif // defined(_LIBCPP_ABI_MICROSOFT)
+
+class _LIBCPP_EXCEPTION_ABI bad_cast
+    : public exception
+{
+public:
+#ifdef _LIBCPP_ABI_MICROSOFT
+    bad_cast() _NOEXCEPT {}
+    virtual ~bad_cast() _NOEXCEPT {}
+    virtual const char* what() const _NOEXCEPT
+    {
+      return "std::bad_cast";
+    }
+#else
+  bad_cast() _NOEXCEPT;
+  bad_cast(const bad_cast&) _NOEXCEPT = default;
+  virtual ~bad_cast() _NOEXCEPT;
+  virtual const char* what() const _NOEXCEPT;
+#endif
+};
+
+class _LIBCPP_EXCEPTION_ABI bad_typeid
+    : public exception
+{
+public:
+#ifdef _LIBCPP_ABI_MICROSOFT
+    bad_typeid() _NOEXCEPT {}
+    virtual ~bad_typeid() _NOEXCEPT {}
+    virtual const char* what() const _NOEXCEPT
+    {
+      return "std::bad_typeid";
+    }
+#else
+  bad_typeid() _NOEXCEPT;
+  virtual ~bad_typeid() _NOEXCEPT;
+  virtual const char* what() const _NOEXCEPT;
+#endif
+};
+
+}  // std
+
+#ifdef _LIBCPP_ABI_MICROSOFT
+class type_info : public std::type_info {};
+#endif
+
+#endif // defined(_LIBCPP_ABI_VCRUNTIME)
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY
+void __throw_bad_cast()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw bad_cast();
+#else
+    _VSTD::abort();
+#endif
+}
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // __LIBCPP_TYPEINFO
diff --git a/contrib/libs/cxxsupp/libcxx/include/unordered_map b/contrib/libs/cxxsupp/libcxx/include/unordered_map
new file mode 100644
index 00000000000..417180a530e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/unordered_map
@@ -0,0 +1,2594 @@
+// -*- C++ -*-
+//===-------------------------- unordered_map -----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_UNORDERED_MAP
+#define _LIBCPP_UNORDERED_MAP
+
+/*
+
+    unordered_map synopsis
+
+#include <initializer_list>
+
+namespace std
+{
+
+template <class Key, class T, class Hash = hash<Key>, class Pred = equal_to<Key>,
+          class Alloc = allocator<pair<const Key, T>>>
+class unordered_map
+{
+public:
+    // types
+    typedef Key                                                        key_type;
+    typedef T                                                          mapped_type;
+    typedef Hash                                                       hasher;
+    typedef Pred                                                       key_equal;
+    typedef Alloc                                                      allocator_type;
+    typedef pair<const key_type, mapped_type>                          value_type;
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    typedef typename allocator_traits<allocator_type>::pointer         pointer;
+    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
+    typedef typename allocator_traits<allocator_type>::size_type       size_type;
+    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
+
+    typedef /unspecified/ iterator;
+    typedef /unspecified/ const_iterator;
+    typedef /unspecified/ local_iterator;
+    typedef /unspecified/ const_local_iterator;
+
+    typedef unspecified                             node_type;            // C++17
+    typedef INSERT_RETURN_TYPE<iterator, node_type> insert_return_type;   // C++17
+
+    unordered_map()
+        noexcept(
+            is_nothrow_default_constructible<hasher>::value &&
+            is_nothrow_default_constructible<key_equal>::value &&
+            is_nothrow_default_constructible<allocator_type>::value);
+    explicit unordered_map(size_type n, const hasher& hf = hasher(),
+                           const key_equal& eql = key_equal(),
+                           const allocator_type& a = allocator_type());
+    template <class InputIterator>
+        unordered_map(InputIterator f, InputIterator l,
+                      size_type n = 0, const hasher& hf = hasher(),
+                      const key_equal& eql = key_equal(),
+                      const allocator_type& a = allocator_type());
+    explicit unordered_map(const allocator_type&);
+    unordered_map(const unordered_map&);
+    unordered_map(const unordered_map&, const Allocator&);
+    unordered_map(unordered_map&&)
+        noexcept(
+            is_nothrow_move_constructible<hasher>::value &&
+            is_nothrow_move_constructible<key_equal>::value &&
+            is_nothrow_move_constructible<allocator_type>::value);
+    unordered_map(unordered_map&&, const Allocator&);
+    unordered_map(initializer_list<value_type>, size_type n = 0,
+                  const hasher& hf = hasher(), const key_equal& eql = key_equal(),
+                  const allocator_type& a = allocator_type());
+    unordered_map(size_type n, const allocator_type& a)
+      : unordered_map(n, hasher(), key_equal(), a) {}  // C++14
+    unordered_map(size_type n, const hasher& hf, const allocator_type& a)
+      : unordered_map(n, hf, key_equal(), a) {}  // C++14
+    template <class InputIterator>
+      unordered_map(InputIterator f, InputIterator l, size_type n, const allocator_type& a)
+      : unordered_map(f, l, n, hasher(), key_equal(), a) {}  // C++14
+    template <class InputIterator>
+      unordered_map(InputIterator f, InputIterator l, size_type n, const hasher& hf,
+        const allocator_type& a)
+      : unordered_map(f, l, n, hf, key_equal(), a) {}  // C++14
+    unordered_map(initializer_list<value_type> il, size_type n, const allocator_type& a)
+      : unordered_map(il, n, hasher(), key_equal(), a) {}  // C++14
+    unordered_map(initializer_list<value_type> il, size_type n, const hasher& hf,
+      const allocator_type& a)
+      : unordered_map(il, n, hf, key_equal(), a) {}  // C++14
+    ~unordered_map();
+    unordered_map& operator=(const unordered_map&);
+    unordered_map& operator=(unordered_map&&)
+        noexcept(
+            allocator_type::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<allocator_type>::value &&
+            is_nothrow_move_assignable<hasher>::value &&
+            is_nothrow_move_assignable<key_equal>::value);
+    unordered_map& operator=(initializer_list<value_type>);
+
+    allocator_type get_allocator() const noexcept;
+
+    bool      empty() const noexcept;
+    size_type size() const noexcept;
+    size_type max_size() const noexcept;
+
+    iterator       begin() noexcept;
+    iterator       end() noexcept;
+    const_iterator begin()  const noexcept;
+    const_iterator end()    const noexcept;
+    const_iterator cbegin() const noexcept;
+    const_iterator cend()   const noexcept;
+
+    template <class... Args>
+        pair<iterator, bool> emplace(Args&&... args);
+    template <class... Args>
+        iterator emplace_hint(const_iterator position, Args&&... args);
+    pair<iterator, bool> insert(const value_type& obj);
+    template <class P>
+        pair<iterator, bool> insert(P&& obj);
+    iterator insert(const_iterator hint, const value_type& obj);
+    template <class P>
+        iterator insert(const_iterator hint, P&& obj);
+    template <class InputIterator>
+        void insert(InputIterator first, InputIterator last);
+    void insert(initializer_list<value_type>);
+
+    node_type extract(const_iterator position);                                       // C++17
+    node_type extract(const key_type& x);                                             // C++17
+    insert_return_type insert(node_type&& nh);                                        // C++17
+    iterator           insert(const_iterator hint, node_type&& nh);                   // C++17
+
+    template <class... Args>
+        pair<iterator, bool> try_emplace(const key_type& k, Args&&... args);          // C++17
+    template <class... Args>
+        pair<iterator, bool> try_emplace(key_type&& k, Args&&... args);               // C++17
+    template <class... Args>
+        iterator try_emplace(const_iterator hint, const key_type& k, Args&&... args); // C++17
+    template <class... Args>
+        iterator try_emplace(const_iterator hint, key_type&& k, Args&&... args);      // C++17
+    template <class M>
+        pair<iterator, bool> insert_or_assign(const key_type& k, M&& obj);            // C++17
+    template <class M>
+        pair<iterator, bool> insert_or_assign(key_type&& k, M&& obj);                 // C++17
+    template <class M>
+        iterator insert_or_assign(const_iterator hint, const key_type& k, M&& obj);   // C++17
+    template <class M>
+        iterator insert_or_assign(const_iterator hint, key_type&& k, M&& obj);        // C++17
+
+    iterator erase(const_iterator position);
+    iterator erase(iterator position);  // C++14
+    size_type erase(const key_type& k);
+    iterator erase(const_iterator first, const_iterator last);
+    void clear() noexcept;
+
+    template<class H2, class P2>
+      void merge(unordered_map<Key, T, H2, P2, Allocator>& source);         // C++17
+    template<class H2, class P2>
+      void merge(unordered_map<Key, T, H2, P2, Allocator>&& source);        // C++17
+    template<class H2, class P2>
+      void merge(unordered_multimap<Key, T, H2, P2, Allocator>& source);    // C++17
+    template<class H2, class P2>
+      void merge(unordered_multimap<Key, T, H2, P2, Allocator>&& source);   // C++17
+
+    void swap(unordered_map&)
+        noexcept(
+            (!allocator_type::propagate_on_container_swap::value ||
+             __is_nothrow_swappable<allocator_type>::value) &&
+            __is_nothrow_swappable<hasher>::value &&
+            __is_nothrow_swappable<key_equal>::value);
+
+    hasher hash_function() const;
+    key_equal key_eq() const;
+
+    iterator       find(const key_type& k);
+    const_iterator find(const key_type& k) const;
+    template<typename K>
+        iterator find(const K& x);              // C++20
+    template<typename K>
+        const_iterator find(const K& x) const;  // C++20
+    size_type count(const key_type& k) const;
+    template<typename K>
+        size_type count(const K& k) const; // C++20
+    bool contains(const key_type& k) const; // C++20
+    template<typename K>
+        bool contains(const K& k) const; // C++20
+    pair<iterator, iterator>             equal_range(const key_type& k);
+    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
+    template<typename K>
+        pair<iterator, iterator>             equal_range(const K& k); // C++20
+    template<typename K>
+        pair<const_iterator, const_iterator> equal_range(const K& k) const; // C++20
+
+    mapped_type& operator[](const key_type& k);
+    mapped_type& operator[](key_type&& k);
+
+    mapped_type&       at(const key_type& k);
+    const mapped_type& at(const key_type& k) const;
+
+    size_type bucket_count() const noexcept;
+    size_type max_bucket_count() const noexcept;
+
+    size_type bucket_size(size_type n) const;
+    size_type bucket(const key_type& k) const;
+
+    local_iterator       begin(size_type n);
+    local_iterator       end(size_type n);
+    const_local_iterator begin(size_type n) const;
+    const_local_iterator end(size_type n) const;
+    const_local_iterator cbegin(size_type n) const;
+    const_local_iterator cend(size_type n) const;
+
+    float load_factor() const noexcept;
+    float max_load_factor() const noexcept;
+    void max_load_factor(float z);
+    void rehash(size_type n);
+    void reserve(size_type n);
+};
+
+template <class Key, class T, class Hash, class Pred, class Alloc>
+    void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x,
+              unordered_map<Key, T, Hash, Pred, Alloc>& y)
+              noexcept(noexcept(x.swap(y)));
+
+template <class Key, class T, class Hash, class Pred, class Alloc>
+    bool
+    operator==(const unordered_map<Key, T, Hash, Pred, Alloc>& x,
+               const unordered_map<Key, T, Hash, Pred, Alloc>& y);
+
+template <class Key, class T, class Hash, class Pred, class Alloc>
+    bool
+    operator!=(const unordered_map<Key, T, Hash, Pred, Alloc>& x,
+               const unordered_map<Key, T, Hash, Pred, Alloc>& y);
+
+template <class Key, class T, class Hash = hash<Key>, class Pred = equal_to<Key>,
+          class Alloc = allocator<pair<const Key, T>>>
+class unordered_multimap
+{
+public:
+    // types
+    typedef Key                                                        key_type;
+    typedef T                                                          mapped_type;
+    typedef Hash                                                       hasher;
+    typedef Pred                                                       key_equal;
+    typedef Alloc                                                      allocator_type;
+    typedef pair<const key_type, mapped_type>                          value_type;
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    typedef typename allocator_traits<allocator_type>::pointer         pointer;
+    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
+    typedef typename allocator_traits<allocator_type>::size_type       size_type;
+    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
+
+    typedef /unspecified/ iterator;
+    typedef /unspecified/ const_iterator;
+    typedef /unspecified/ local_iterator;
+    typedef /unspecified/ const_local_iterator;
+
+    typedef unspecified node_type;    // C++17
+
+    unordered_multimap()
+        noexcept(
+            is_nothrow_default_constructible<hasher>::value &&
+            is_nothrow_default_constructible<key_equal>::value &&
+            is_nothrow_default_constructible<allocator_type>::value);
+    explicit unordered_multimap(size_type n, const hasher& hf = hasher(),
+                           const key_equal& eql = key_equal(),
+                           const allocator_type& a = allocator_type());
+    template <class InputIterator>
+        unordered_multimap(InputIterator f, InputIterator l,
+                      size_type n = 0, const hasher& hf = hasher(),
+                      const key_equal& eql = key_equal(),
+                      const allocator_type& a = allocator_type());
+    explicit unordered_multimap(const allocator_type&);
+    unordered_multimap(const unordered_multimap&);
+    unordered_multimap(const unordered_multimap&, const Allocator&);
+    unordered_multimap(unordered_multimap&&)
+        noexcept(
+            is_nothrow_move_constructible<hasher>::value &&
+            is_nothrow_move_constructible<key_equal>::value &&
+            is_nothrow_move_constructible<allocator_type>::value);
+    unordered_multimap(unordered_multimap&&, const Allocator&);
+    unordered_multimap(initializer_list<value_type>, size_type n = 0,
+                  const hasher& hf = hasher(), const key_equal& eql = key_equal(),
+                  const allocator_type& a = allocator_type());
+    unordered_multimap(size_type n, const allocator_type& a)
+      : unordered_multimap(n, hasher(), key_equal(), a) {}  // C++14
+    unordered_multimap(size_type n, const hasher& hf, const allocator_type& a)
+      : unordered_multimap(n, hf, key_equal(), a) {}  // C++14
+    template <class InputIterator>
+      unordered_multimap(InputIterator f, InputIterator l, size_type n, const allocator_type& a)
+      : unordered_multimap(f, l, n, hasher(), key_equal(), a) {}  // C++14
+    template <class InputIterator>
+      unordered_multimap(InputIterator f, InputIterator l, size_type n, const hasher& hf,
+        const allocator_type& a)
+      : unordered_multimap(f, l, n, hf, key_equal(), a) {}  // C++14
+    unordered_multimap(initializer_list<value_type> il, size_type n, const allocator_type& a)
+      : unordered_multimap(il, n, hasher(), key_equal(), a) {}  // C++14
+    unordered_multimap(initializer_list<value_type> il, size_type n, const hasher& hf,
+      const allocator_type& a)
+      : unordered_multimap(il, n, hf, key_equal(), a) {}  // C++14
+    ~unordered_multimap();
+    unordered_multimap& operator=(const unordered_multimap&);
+    unordered_multimap& operator=(unordered_multimap&&)
+        noexcept(
+            allocator_type::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<allocator_type>::value &&
+            is_nothrow_move_assignable<hasher>::value &&
+            is_nothrow_move_assignable<key_equal>::value);
+    unordered_multimap& operator=(initializer_list<value_type>);
+
+    allocator_type get_allocator() const noexcept;
+
+    bool      empty() const noexcept;
+    size_type size() const noexcept;
+    size_type max_size() const noexcept;
+
+    iterator       begin() noexcept;
+    iterator       end() noexcept;
+    const_iterator begin()  const noexcept;
+    const_iterator end()    const noexcept;
+    const_iterator cbegin() const noexcept;
+    const_iterator cend()   const noexcept;
+
+    template <class... Args>
+        iterator emplace(Args&&... args);
+    template <class... Args>
+        iterator emplace_hint(const_iterator position, Args&&... args);
+    iterator insert(const value_type& obj);
+    template <class P>
+        iterator insert(P&& obj);
+    iterator insert(const_iterator hint, const value_type& obj);
+    template <class P>
+        iterator insert(const_iterator hint, P&& obj);
+    template <class InputIterator>
+        void insert(InputIterator first, InputIterator last);
+    void insert(initializer_list<value_type>);
+
+    node_type extract(const_iterator position);                // C++17
+    node_type extract(const key_type& x);                      // C++17
+    iterator insert(node_type&& nh);                           // C++17
+    iterator insert(const_iterator hint, node_type&& nh);      // C++17
+
+    iterator erase(const_iterator position);
+    iterator erase(iterator position);  // C++14
+    size_type erase(const key_type& k);
+    iterator erase(const_iterator first, const_iterator last);
+    void clear() noexcept;
+
+    template<class H2, class P2>
+      void merge(unordered_multimap<Key, T, H2, P2, Allocator>& source);    // C++17
+    template<class H2, class P2>
+      void merge(unordered_multimap<Key, T, H2, P2, Allocator>&& source);   // C++17
+    template<class H2, class P2>
+      void merge(unordered_map<Key, T, H2, P2, Allocator>& source);         // C++17
+    template<class H2, class P2>
+      void merge(unordered_map<Key, T, H2, P2, Allocator>&& source);        // C++17
+
+    void swap(unordered_multimap&)
+        noexcept(
+            (!allocator_type::propagate_on_container_swap::value ||
+             __is_nothrow_swappable<allocator_type>::value) &&
+            __is_nothrow_swappable<hasher>::value &&
+            __is_nothrow_swappable<key_equal>::value);
+
+    hasher hash_function() const;
+    key_equal key_eq() const;
+
+    iterator       find(const key_type& k);
+    const_iterator find(const key_type& k) const;
+    template<typename K>
+        iterator find(const K& x);              // C++20
+    template<typename K>
+        const_iterator find(const K& x) const;  // C++20
+    size_type count(const key_type& k) const;
+    template<typename K>
+        size_type count(const K& k) const; // C++20
+    bool contains(const key_type& k) const; // C++20
+    template<typename K>
+        bool contains(const K& k) const; // C++20
+    pair<iterator, iterator>             equal_range(const key_type& k);
+    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
+    template<typename K>
+        pair<iterator, iterator>             equal_range(const K& k); // C++20
+    template<typename K>
+        pair<const_iterator, const_iterator> equal_range(const K& k) const; // C++20
+
+    size_type bucket_count() const noexcept;
+    size_type max_bucket_count() const noexcept;
+
+    size_type bucket_size(size_type n) const;
+    size_type bucket(const key_type& k) const;
+
+    local_iterator       begin(size_type n);
+    local_iterator       end(size_type n);
+    const_local_iterator begin(size_type n) const;
+    const_local_iterator end(size_type n) const;
+    const_local_iterator cbegin(size_type n) const;
+    const_local_iterator cend(size_type n) const;
+
+    float load_factor() const noexcept;
+    float max_load_factor() const noexcept;
+    void max_load_factor(float z);
+    void rehash(size_type n);
+    void reserve(size_type n);
+};
+
+template <class Key, class T, class Hash, class Pred, class Alloc>
+    void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x,
+              unordered_multimap<Key, T, Hash, Pred, Alloc>& y)
+              noexcept(noexcept(x.swap(y)));
+
+template <class K, class T, class H, class P, class A, class Predicate>
+    typename unordered_map<K, T, H, P, A>::size_type
+    erase_if(unordered_map<K, T, H, P, A>& c, Predicate pred);       // C++20
+
+template <class K, class T, class H, class P, class A, class Predicate>
+    typename unordered_multimap<K, T, H, P, A>::size_type
+    erase_if(unordered_multimap<K, T, H, P, A>& c, Predicate pred);  // C++20
+
+template <class Key, class T, class Hash, class Pred, class Alloc>
+    bool
+    operator==(const unordered_multimap<Key, T, Hash, Pred, Alloc>& x,
+               const unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
+
+template <class Key, class T, class Hash, class Pred, class Alloc>
+    bool
+    operator!=(const unordered_multimap<Key, T, Hash, Pred, Alloc>& x,
+               const unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__functional/is_transparent.h>
+#include <__hash_table>
+#include <__node_handle>
+#include <__utility/forward.h>
+#include <compare>
+#include <functional>
+#include <iterator> // __libcpp_erase_if_container
+#include <stdexcept>
+#include <tuple>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Key, class _Cp, class _Hash, class _Pred,
+          bool = is_empty<_Hash>::value && !__libcpp_is_final<_Hash>::value>
+class __unordered_map_hasher
+    : private _Hash
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __unordered_map_hasher()
+        _NOEXCEPT_(is_nothrow_default_constructible<_Hash>::value)
+        : _Hash() {}
+    _LIBCPP_INLINE_VISIBILITY
+    __unordered_map_hasher(const _Hash& __h)
+        _NOEXCEPT_(is_nothrow_copy_constructible<_Hash>::value)
+        : _Hash(__h) {}
+    _LIBCPP_INLINE_VISIBILITY
+    const _Hash& hash_function() const _NOEXCEPT {return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const _Cp& __x) const
+        {return static_cast<const _Hash&>(*this)(__x.__get_value().first);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const _Key& __x) const
+        {return static_cast<const _Hash&>(*this)(__x);}
+#if _LIBCPP_STD_VER > 17
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const _K2& __x) const
+        {return static_cast<const _Hash&>(*this)(__x);}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(__unordered_map_hasher& __y)
+        _NOEXCEPT_(__is_nothrow_swappable<_Hash>::value)
+    {
+        using _VSTD::swap;
+        swap(static_cast<_Hash&>(*this), static_cast<_Hash&>(__y));
+    }
+};
+
+template <class _Key, class _Cp, class _Hash, class _Pred>
+class __unordered_map_hasher<_Key, _Cp, _Hash, _Pred, false>
+{
+    _Hash __hash_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __unordered_map_hasher()
+        _NOEXCEPT_(is_nothrow_default_constructible<_Hash>::value)
+        : __hash_() {}
+    _LIBCPP_INLINE_VISIBILITY
+    __unordered_map_hasher(const _Hash& __h)
+        _NOEXCEPT_(is_nothrow_copy_constructible<_Hash>::value)
+        : __hash_(__h) {}
+    _LIBCPP_INLINE_VISIBILITY
+    const _Hash& hash_function() const _NOEXCEPT {return __hash_;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const _Cp& __x) const
+        {return __hash_(__x.__get_value().first);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const _Key& __x) const
+        {return __hash_(__x);}
+#if _LIBCPP_STD_VER > 17
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const _K2& __x) const
+        {return __hash_(__x);}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(__unordered_map_hasher& __y)
+        _NOEXCEPT_(__is_nothrow_swappable<_Hash>::value)
+    {
+        using _VSTD::swap;
+        swap(__hash_, __y.__hash_);
+    }
+};
+
+template <class _Key, class _Cp, class _Hash, class _Pred, bool __b>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(__unordered_map_hasher<_Key, _Cp, _Hash, _Pred, __b>& __x,
+     __unordered_map_hasher<_Key, _Cp, _Hash, _Pred, __b>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+template <class _Key, class _Cp, class _Pred, class _Hash,
+          bool = is_empty<_Pred>::value && !__libcpp_is_final<_Pred>::value>
+class __unordered_map_equal
+    : private _Pred
+{
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __unordered_map_equal()
+        _NOEXCEPT_(is_nothrow_default_constructible<_Pred>::value)
+        : _Pred() {}
+    _LIBCPP_INLINE_VISIBILITY
+    __unordered_map_equal(const _Pred& __p)
+        _NOEXCEPT_(is_nothrow_copy_constructible<_Pred>::value)
+        : _Pred(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    const _Pred& key_eq() const _NOEXCEPT {return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Cp& __x, const _Cp& __y) const
+        {return static_cast<const _Pred&>(*this)(__x.__get_value().first, __y.__get_value().first);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Cp& __x, const _Key& __y) const
+        {return static_cast<const _Pred&>(*this)(__x.__get_value().first, __y);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Key& __x, const _Cp& __y) const
+        {return static_cast<const _Pred&>(*this)(__x, __y.__get_value().first);}
+#if _LIBCPP_STD_VER > 17
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Cp& __x, const _K2& __y) const
+        {return static_cast<const _Pred&>(*this)(__x.__get_value().first, __y);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _K2& __x, const _Cp& __y) const
+        {return static_cast<const _Pred&>(*this)(__x, __y.__get_value().first);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Key& __x, const _K2& __y) const
+        {return static_cast<const _Pred&>(*this)(__x, __y);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _K2& __x, const _Key& __y) const
+        {return static_cast<const _Pred&>(*this)(__x, __y);}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(__unordered_map_equal& __y)
+        _NOEXCEPT_(__is_nothrow_swappable<_Pred>::value)
+    {
+        using _VSTD::swap;
+        swap(static_cast<_Pred&>(*this), static_cast<_Pred&>(__y));
+    }
+};
+
+template <class _Key, class _Cp, class _Pred, class _Hash>
+class __unordered_map_equal<_Key, _Cp, _Pred, _Hash, false>
+{
+    _Pred __pred_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __unordered_map_equal()
+        _NOEXCEPT_(is_nothrow_default_constructible<_Pred>::value)
+        : __pred_() {}
+    _LIBCPP_INLINE_VISIBILITY
+    __unordered_map_equal(const _Pred& __p)
+        _NOEXCEPT_(is_nothrow_copy_constructible<_Pred>::value)
+        : __pred_(__p) {}
+    _LIBCPP_INLINE_VISIBILITY
+    const _Pred& key_eq() const _NOEXCEPT {return __pred_;}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Cp& __x, const _Cp& __y) const
+        {return __pred_(__x.__get_value().first, __y.__get_value().first);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Cp& __x, const _Key& __y) const
+        {return __pred_(__x.__get_value().first, __y);}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Key& __x, const _Cp& __y) const
+        {return __pred_(__x, __y.__get_value().first);}
+#if _LIBCPP_STD_VER > 17
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Cp& __x, const _K2& __y) const
+        {return __pred_(__x.__get_value().first, __y);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _K2& __x, const _Cp& __y) const
+        {return __pred_(__x, __y.__get_value().first);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _Key& __x, const _K2& __y) const
+        {return __pred_(__x, __y);}
+    template <typename _K2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _K2& __x, const _Key& __y) const
+        {return __pred_(__x, __y);}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(__unordered_map_equal& __y)
+        _NOEXCEPT_(__is_nothrow_swappable<_Pred>::value)
+    {
+        using _VSTD::swap;
+        swap(__pred_, __y.__pred_);
+    }
+};
+
+template <class _Key, class _Cp, class _Pred, class _Hash, bool __b>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(__unordered_map_equal<_Key, _Cp, _Pred, _Hash, __b>& __x,
+     __unordered_map_equal<_Key, _Cp, _Pred, _Hash, __b>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+template <class _Alloc>
+class __hash_map_node_destructor
+{
+    typedef _Alloc                              allocator_type;
+    typedef allocator_traits<allocator_type>    __alloc_traits;
+
+public:
+
+    typedef typename __alloc_traits::pointer       pointer;
+private:
+
+    allocator_type& __na_;
+
+    __hash_map_node_destructor& operator=(const __hash_map_node_destructor&);
+
+public:
+    bool __first_constructed;
+    bool __second_constructed;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __hash_map_node_destructor(allocator_type& __na) _NOEXCEPT
+        : __na_(__na),
+          __first_constructed(false),
+          __second_constructed(false)
+        {}
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_node_destructor(__hash_node_destructor<allocator_type>&& __x)
+        _NOEXCEPT
+        : __na_(__x.__na_),
+          __first_constructed(__x.__value_constructed),
+          __second_constructed(__x.__value_constructed)
+        {
+            __x.__value_constructed = false;
+        }
+#else  // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_node_destructor(const __hash_node_destructor<allocator_type>& __x)
+        : __na_(__x.__na_),
+          __first_constructed(__x.__value_constructed),
+          __second_constructed(__x.__value_constructed)
+        {
+            const_cast<bool&>(__x.__value_constructed) = false;
+        }
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator()(pointer __p) _NOEXCEPT
+    {
+        if (__second_constructed)
+            __alloc_traits::destroy(__na_, _VSTD::addressof(__p->__value_.__get_value().second));
+        if (__first_constructed)
+            __alloc_traits::destroy(__na_, _VSTD::addressof(__p->__value_.__get_value().first));
+        if (__p)
+            __alloc_traits::deallocate(__na_, __p, 1);
+    }
+};
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Key, class _Tp>
+struct _LIBCPP_STANDALONE_DEBUG __hash_value_type
+{
+    typedef _Key                                     key_type;
+    typedef _Tp                                      mapped_type;
+    typedef pair<const key_type, mapped_type>        value_type;
+    typedef pair<key_type&, mapped_type&>            __nc_ref_pair_type;
+    typedef pair<key_type&&, mapped_type&&>          __nc_rref_pair_type;
+
+private:
+    value_type __cc;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    value_type& __get_value()
+    {
+#if _LIBCPP_STD_VER > 14
+        return *_VSTD::launder(_VSTD::addressof(__cc));
+#else
+        return __cc;
+#endif
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    const value_type& __get_value() const
+    {
+#if _LIBCPP_STD_VER > 14
+        return *_VSTD::launder(_VSTD::addressof(__cc));
+#else
+        return __cc;
+#endif
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __nc_ref_pair_type __ref()
+    {
+        value_type& __v = __get_value();
+        return __nc_ref_pair_type(const_cast<key_type&>(__v.first), __v.second);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __nc_rref_pair_type __move()
+    {
+        value_type& __v = __get_value();
+        return __nc_rref_pair_type(
+            _VSTD::move(const_cast<key_type&>(__v.first)),
+            _VSTD::move(__v.second));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_value_type& operator=(const __hash_value_type& __v)
+    {
+        __ref() = __v.__get_value();
+        return *this;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_value_type& operator=(__hash_value_type&& __v)
+    {
+        __ref() = __v.__move();
+        return *this;
+    }
+
+    template <class _ValueTp,
+              class = typename enable_if<
+                    __is_same_uncvref<_ValueTp, value_type>::value
+                 >::type
+             >
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_value_type& operator=(_ValueTp&& __v)
+    {
+        __ref() = _VSTD::forward<_ValueTp>(__v);
+        return *this;
+    }
+
+private:
+    __hash_value_type(const __hash_value_type& __v) = delete;
+    __hash_value_type(__hash_value_type&& __v) = delete;
+    template <class ..._Args>
+    explicit __hash_value_type(_Args&& ...__args) = delete;
+
+    ~__hash_value_type() = delete;
+};
+
+#else
+
+template <class _Key, class _Tp>
+struct __hash_value_type
+{
+    typedef _Key                                     key_type;
+    typedef _Tp                                      mapped_type;
+    typedef pair<const key_type, mapped_type>        value_type;
+
+private:
+    value_type __cc;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    value_type& __get_value() { return __cc; }
+    _LIBCPP_INLINE_VISIBILITY
+    const value_type& __get_value() const { return __cc; }
+
+private:
+   ~__hash_value_type();
+};
+
+#endif
+
+template <class _HashIterator>
+class _LIBCPP_TEMPLATE_VIS __hash_map_iterator
+{
+    _HashIterator __i_;
+
+    typedef  __hash_node_types_from_iterator<_HashIterator> _NodeTypes;
+
+public:
+    typedef forward_iterator_tag                                 iterator_category;
+    typedef typename _NodeTypes::__map_value_type                value_type;
+    typedef typename _NodeTypes::difference_type                 difference_type;
+    typedef value_type&                                          reference;
+    typedef typename _NodeTypes::__map_value_type_pointer       pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_iterator() _NOEXCEPT {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_iterator(_HashIterator __i) _NOEXCEPT : __i_(__i) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {return __i_->__get_value();}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {return pointer_traits<pointer>::pointer_to(__i_->__get_value());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_iterator& operator++() {++__i_; return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_iterator operator++(int)
+    {
+        __hash_map_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const __hash_map_iterator& __x, const __hash_map_iterator& __y)
+        {return __x.__i_ == __y.__i_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const __hash_map_iterator& __x, const __hash_map_iterator& __y)
+        {return __x.__i_ != __y.__i_;}
+
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
+};
+
+template <class _HashIterator>
+class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator
+{
+    _HashIterator __i_;
+
+    typedef  __hash_node_types_from_iterator<_HashIterator> _NodeTypes;
+
+public:
+    typedef forward_iterator_tag                                 iterator_category;
+    typedef typename _NodeTypes::__map_value_type                value_type;
+    typedef typename _NodeTypes::difference_type                 difference_type;
+    typedef const value_type&                                    reference;
+    typedef typename _NodeTypes::__const_map_value_type_pointer  pointer;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_const_iterator() _NOEXCEPT {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_const_iterator(_HashIterator __i) _NOEXCEPT : __i_(__i) {}
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_const_iterator(
+            __hash_map_iterator<typename _HashIterator::__non_const_iterator> __i)
+                 _NOEXCEPT
+                : __i_(__i.__i_) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reference operator*() const {return __i_->__get_value();}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer operator->() const {return pointer_traits<pointer>::pointer_to(__i_->__get_value());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_const_iterator& operator++() {++__i_; return *this;}
+    _LIBCPP_INLINE_VISIBILITY
+    __hash_map_const_iterator operator++(int)
+    {
+        __hash_map_const_iterator __t(*this);
+        ++(*this);
+        return __t;
+    }
+
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator==(const __hash_map_const_iterator& __x, const __hash_map_const_iterator& __y)
+        {return __x.__i_ == __y.__i_;}
+    friend _LIBCPP_INLINE_VISIBILITY
+        bool operator!=(const __hash_map_const_iterator& __x, const __hash_map_const_iterator& __y)
+        {return __x.__i_ != __y.__i_;}
+
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
+    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
+};
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+class unordered_multimap;
+
+template <class _Key, class _Tp, class _Hash = hash<_Key>, class _Pred = equal_to<_Key>,
+          class _Alloc = allocator<pair<const _Key, _Tp> > >
+class _LIBCPP_TEMPLATE_VIS unordered_map
+{
+public:
+    // types
+    typedef _Key                                           key_type;
+    typedef _Tp                                            mapped_type;
+    typedef __identity_t<_Hash>                            hasher;
+    typedef __identity_t<_Pred>                            key_equal;
+    typedef __identity_t<_Alloc>                           allocator_type;
+    typedef pair<const key_type, mapped_type>              value_type;
+    typedef value_type&                                    reference;
+    typedef const value_type&                              const_reference;
+    static_assert((is_same<value_type, typename allocator_type::value_type>::value),
+                  "Invalid allocator::value_type");
+
+private:
+    typedef __hash_value_type<key_type, mapped_type>                          __value_type;
+    typedef __unordered_map_hasher<key_type, __value_type, hasher, key_equal> __hasher;
+    typedef __unordered_map_equal<key_type, __value_type, key_equal, hasher>  __key_equal;
+    typedef typename __rebind_alloc_helper<allocator_traits<allocator_type>,
+                                                 __value_type>::type          __allocator_type;
+
+    typedef __hash_table<__value_type, __hasher,
+                         __key_equal,  __allocator_type>   __table;
+
+    __table __table_;
+
+    typedef typename __table::_NodeTypes                   _NodeTypes;
+    typedef typename __table::__node_pointer               __node_pointer;
+    typedef typename __table::__node_const_pointer         __node_const_pointer;
+    typedef typename __table::__node_traits                __node_traits;
+    typedef typename __table::__node_allocator             __node_allocator;
+    typedef typename __table::__node                       __node;
+    typedef __hash_map_node_destructor<__node_allocator>   _Dp;
+    typedef unique_ptr<__node, _Dp>                         __node_holder;
+    typedef allocator_traits<allocator_type>               __alloc_traits;
+
+    static_assert((is_same<typename __table::__container_value_type, value_type>::value), "");
+    static_assert((is_same<typename __table::__node_value_type, __value_type>::value), "");
+public:
+    typedef typename __alloc_traits::pointer         pointer;
+    typedef typename __alloc_traits::const_pointer   const_pointer;
+    typedef typename __table::size_type              size_type;
+    typedef typename __table::difference_type        difference_type;
+
+    typedef __hash_map_iterator<typename __table::iterator>       iterator;
+    typedef __hash_map_const_iterator<typename __table::const_iterator> const_iterator;
+    typedef __hash_map_iterator<typename __table::local_iterator> local_iterator;
+    typedef __hash_map_const_iterator<typename __table::const_local_iterator> const_local_iterator;
+
+#if _LIBCPP_STD_VER > 14
+    typedef __map_node_handle<__node, allocator_type> node_type;
+    typedef __insert_return_type<iterator, node_type> insert_return_type;
+#endif
+
+    template <class _Key2, class _Tp2, class _Hash2, class _Pred2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS unordered_map;
+    template <class _Key2, class _Tp2, class _Hash2, class _Pred2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
+
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_map()
+        _NOEXCEPT_(is_nothrow_default_constructible<__table>::value)
+        {
+#if _LIBCPP_DEBUG_LEVEL == 2
+            __get_db()->__insert_c(this);
+#endif
+        }
+    explicit unordered_map(size_type __n, const hasher& __hf = hasher(),
+                           const key_equal& __eql = key_equal());
+    unordered_map(size_type __n, const hasher& __hf,
+                  const key_equal& __eql,
+                  const allocator_type& __a);
+    template <class _InputIterator>
+        unordered_map(_InputIterator __first, _InputIterator __last);
+    template <class _InputIterator>
+        unordered_map(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf = hasher(),
+                      const key_equal& __eql = key_equal());
+    template <class _InputIterator>
+        unordered_map(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf,
+                      const key_equal& __eql,
+                      const allocator_type& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    explicit unordered_map(const allocator_type& __a);
+    unordered_map(const unordered_map& __u);
+    unordered_map(const unordered_map& __u, const allocator_type& __a);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_map(unordered_map&& __u)
+        _NOEXCEPT_(is_nothrow_move_constructible<__table>::value);
+    unordered_map(unordered_map&& __u, const allocator_type& __a);
+    unordered_map(initializer_list<value_type> __il);
+    unordered_map(initializer_list<value_type> __il, size_type __n,
+                  const hasher& __hf = hasher(), const key_equal& __eql = key_equal());
+    unordered_map(initializer_list<value_type> __il, size_type __n,
+                  const hasher& __hf, const key_equal& __eql,
+                  const allocator_type& __a);
+#endif // _LIBCPP_CXX03_LANG
+#if _LIBCPP_STD_VER > 11
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_map(size_type __n, const allocator_type& __a)
+      : unordered_map(__n, hasher(), key_equal(), __a) {}
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_map(size_type __n, const hasher& __hf, const allocator_type& __a)
+      : unordered_map(__n, __hf, key_equal(), __a) {}
+    template <class _InputIterator>
+    _LIBCPP_INLINE_VISIBILITY
+      unordered_map(_InputIterator __first, _InputIterator __last, size_type __n, const allocator_type& __a)
+      : unordered_map(__first, __last, __n, hasher(), key_equal(), __a) {}
+    template <class _InputIterator>
+    _LIBCPP_INLINE_VISIBILITY
+      unordered_map(_InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf,
+        const allocator_type& __a)
+      : unordered_map(__first, __last, __n, __hf, key_equal(), __a) {}
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_map(initializer_list<value_type> __il, size_type __n, const allocator_type& __a)
+      : unordered_map(__il, __n, hasher(), key_equal(), __a) {}
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_map(initializer_list<value_type> __il, size_type __n, const hasher& __hf,
+      const allocator_type& __a)
+      : unordered_map(__il, __n, __hf, key_equal(), __a) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    ~unordered_map() {
+        static_assert(sizeof(__diagnose_unordered_container_requirements<_Key, _Hash, _Pred>(0)), "");
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_map& operator=(const unordered_map& __u)
+    {
+#ifndef _LIBCPP_CXX03_LANG
+        __table_ = __u.__table_;
+#else
+        if (this != _VSTD::addressof(__u)) {
+            __table_.clear();
+            __table_.hash_function() = __u.__table_.hash_function();
+            __table_.key_eq() = __u.__table_.key_eq();
+            __table_.max_load_factor() = __u.__table_.max_load_factor();
+            __table_.__copy_assign_alloc(__u.__table_);
+            insert(__u.begin(), __u.end());
+        }
+#endif
+        return *this;
+    }
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_map& operator=(unordered_map&& __u)
+        _NOEXCEPT_(is_nothrow_move_assignable<__table>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_map& operator=(initializer_list<value_type> __il);
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT
+        {return allocator_type(__table_.__node_alloc());}
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool      empty() const _NOEXCEPT {return __table_.size() == 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT  {return __table_.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT {return __table_.max_size();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       begin() _NOEXCEPT        {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       end() _NOEXCEPT          {return __table_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin()  const _NOEXCEPT {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()    const _NOEXCEPT {return __table_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin() const _NOEXCEPT {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend()   const _NOEXCEPT {return __table_.end();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> insert(const value_type& __x)
+        {return __table_.__insert_unique(__x);}
+
+    iterator insert(const_iterator __p, const value_type& __x) {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+            "unordered_map::insert(const_iterator, const value_type&) called with an iterator not"
+            " referring to this unordered_map");
+#else
+        ((void)__p);
+#endif
+        return insert(__x).first;
+    }
+
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        void insert(_InputIterator __first, _InputIterator __last);
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void insert(initializer_list<value_type> __il)
+        {insert(__il.begin(), __il.end());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> insert(value_type&& __x)
+        {return __table_.__insert_unique(_VSTD::move(__x));}
+
+    iterator insert(const_iterator __p, value_type&& __x) {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+            "unordered_map::insert(const_iterator, const value_type&) called with an iterator not"
+            " referring to this unordered_map");
+#else
+        ((void)__p);
+#endif
+        return __table_.__insert_unique(_VSTD::move(__x)).first;
+    }
+
+    template <class _Pp,
+              class = typename enable_if<is_constructible<value_type, _Pp>::value>::type>
+        _LIBCPP_INLINE_VISIBILITY
+        pair<iterator, bool> insert(_Pp&& __x)
+            {return __table_.__insert_unique(_VSTD::forward<_Pp>(__x));}
+
+    template <class _Pp,
+              class = typename enable_if<is_constructible<value_type, _Pp>::value>::type>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator insert(const_iterator __p, _Pp&& __x)
+        {
+#if _LIBCPP_DEBUG_LEVEL == 2
+            _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+                "unordered_map::insert(const_iterator, value_type&&) called with an iterator not"
+                " referring to this unordered_map");
+#else
+          ((void)__p);
+#endif
+            return insert(_VSTD::forward<_Pp>(__x)).first;
+        }
+
+    template <class... _Args>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> emplace(_Args&&... __args) {
+        return __table_.__emplace_unique(_VSTD::forward<_Args>(__args)...);
+    }
+
+    template <class... _Args>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator emplace_hint(const_iterator __p, _Args&&... __args) {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+            "unordered_map::emplace_hint(const_iterator, args...) called with an iterator not"
+            " referring to this unordered_map");
+#else
+          ((void)__p);
+#endif
+        return __table_.__emplace_unique(_VSTD::forward<_Args>(__args)...).first;
+    }
+
+#endif // _LIBCPP_CXX03_LANG
+
+#if _LIBCPP_STD_VER > 14
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        pair<iterator, bool> try_emplace(const key_type& __k, _Args&&... __args)
+    {
+        return __table_.__emplace_unique_key_args(__k, piecewise_construct,
+            _VSTD::forward_as_tuple(__k),
+            _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...));
+    }
+
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        pair<iterator, bool> try_emplace(key_type&& __k, _Args&&... __args)
+    {
+        return __table_.__emplace_unique_key_args(__k, piecewise_construct,
+            _VSTD::forward_as_tuple(_VSTD::move(__k)),
+            _VSTD::forward_as_tuple(_VSTD::forward<_Args>(__args)...));
+    }
+
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator try_emplace(const_iterator __h, const key_type& __k, _Args&&... __args)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__h) == this,
+            "unordered_map::try_emplace(const_iterator, key, args...) called with an iterator not"
+            " referring to this unordered_map");
+#else
+        ((void)__h);
+#endif
+        return try_emplace(__k, _VSTD::forward<_Args>(__args)...).first;
+    }
+
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator try_emplace(const_iterator __h, key_type&& __k, _Args&&... __args)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__h) == this,
+            "unordered_map::try_emplace(const_iterator, key, args...) called with an iterator not"
+            " referring to this unordered_map");
+#else
+        ((void)__h);
+#endif
+        return try_emplace(_VSTD::move(__k), _VSTD::forward<_Args>(__args)...).first;
+    }
+
+    template <class _Vp>
+        _LIBCPP_INLINE_VISIBILITY
+        pair<iterator, bool> insert_or_assign(const key_type& __k, _Vp&& __v)
+    {
+        pair<iterator, bool> __res = __table_.__emplace_unique_key_args(__k,
+            __k, _VSTD::forward<_Vp>(__v));
+        if (!__res.second) {
+            __res.first->second = _VSTD::forward<_Vp>(__v);
+        }
+        return __res;
+    }
+
+    template <class _Vp>
+        _LIBCPP_INLINE_VISIBILITY
+        pair<iterator, bool> insert_or_assign(key_type&& __k, _Vp&& __v)
+    {
+        pair<iterator, bool> __res = __table_.__emplace_unique_key_args(__k,
+            _VSTD::move(__k), _VSTD::forward<_Vp>(__v));
+        if (!__res.second) {
+            __res.first->second = _VSTD::forward<_Vp>(__v);
+        }
+        return __res;
+    }
+
+    template <class _Vp>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator insert_or_assign(const_iterator, const key_type& __k, _Vp&& __v)
+     {
+          // FIXME: Add debug mode checking for the iterator input
+          return insert_or_assign(__k, _VSTD::forward<_Vp>(__v)).first;
+     }
+
+    template <class _Vp>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator insert_or_assign(const_iterator, key_type&& __k, _Vp&& __v)
+     {
+        // FIXME: Add debug mode checking for the iterator input
+        return insert_or_assign(_VSTD::move(__k), _VSTD::forward<_Vp>(__v)).first;
+     }
+#endif // _LIBCPP_STD_VER > 14
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(const_iterator __p) {return __table_.erase(__p.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(iterator __p)       {return __table_.erase(__p.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type erase(const key_type& __k) {return __table_.__erase_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(const_iterator __first, const_iterator __last)
+        {return __table_.erase(__first.__i_, __last.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+        void clear() _NOEXCEPT {__table_.clear();}
+
+#if _LIBCPP_STD_VER > 14
+    _LIBCPP_INLINE_VISIBILITY
+    insert_return_type insert(node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to unordered_map::insert()");
+        return __table_.template __node_handle_insert_unique<
+            node_type, insert_return_type>(_VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __hint, node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to unordered_map::insert()");
+        return __table_.template __node_handle_insert_unique<node_type>(
+            __hint.__i_, _VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(key_type const& __key)
+    {
+        return __table_.template __node_handle_extract<node_type>(__key);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(const_iterator __it)
+    {
+        return __table_.template __node_handle_extract<node_type>(
+            __it.__i_);
+    }
+
+    template <class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_map<key_type, mapped_type, _H2, _P2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __table_.__node_handle_merge_unique(__source.__table_);
+    }
+    template <class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_map<key_type, mapped_type, _H2, _P2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __table_.__node_handle_merge_unique(__source.__table_);
+    }
+    template <class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_multimap<key_type, mapped_type, _H2, _P2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __table_.__node_handle_merge_unique(__source.__table_);
+    }
+    template <class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_multimap<key_type, mapped_type, _H2, _P2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __table_.__node_handle_merge_unique(__source.__table_);
+    }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(unordered_map& __u)
+        _NOEXCEPT_(__is_nothrow_swappable<__table>::value)
+        { __table_.swap(__u.__table_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    hasher hash_function() const
+        {return __table_.hash_function().hash_function();}
+    _LIBCPP_INLINE_VISIBILITY
+    key_equal key_eq() const
+        {return __table_.key_eq().key_eq();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       find(const key_type& __k)       {return __table_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const key_type& __k) const {return __table_.find(__k);}
+#if _LIBCPP_STD_VER > 17
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       find(const _K2& __k)            {return __table_.find(__k);}
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const _K2& __k) const      {return __table_.find(__k);}
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type count(const key_type& __k) const {return __table_.__count_unique(__k);}
+#if _LIBCPP_STD_VER > 17
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    size_type count(const _K2& __k) const      {return __table_.__count_unique(__k);}
+#endif // _LIBCPP_STD_VER > 17
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const key_type& __k) const {return find(__k) != end();}
+
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const _K2& __k) const      {return find(__k) != end();}
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, iterator>             equal_range(const key_type& __k)
+        {return __table_.__equal_range_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    pair<const_iterator, const_iterator> equal_range(const key_type& __k) const
+        {return __table_.__equal_range_unique(__k);}
+#if _LIBCPP_STD_VER > 17
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, iterator>             equal_range(const _K2& __k)
+        {return __table_.__equal_range_unique(__k);}
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<const_iterator, const_iterator> equal_range(const _K2& __k) const
+        {return __table_.__equal_range_unique(__k);}
+#endif // _LIBCPP_STD_VER > 17
+
+    mapped_type& operator[](const key_type& __k);
+#ifndef _LIBCPP_CXX03_LANG
+    mapped_type& operator[](key_type&& __k);
+#endif
+
+    mapped_type&       at(const key_type& __k);
+    const mapped_type& at(const key_type& __k) const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket_count() const _NOEXCEPT {return __table_.bucket_count();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_bucket_count() const _NOEXCEPT {return __table_.max_bucket_count();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket_size(size_type __n) const
+        {return __table_.bucket_size(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket(const key_type& __k) const {return __table_.bucket(__k);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    local_iterator       begin(size_type __n)        {return __table_.begin(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    local_iterator       end(size_type __n)          {return __table_.end(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator begin(size_type __n) const  {return __table_.cbegin(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator end(size_type __n) const    {return __table_.cend(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator cbegin(size_type __n) const {return __table_.cbegin(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator cend(size_type __n) const   {return __table_.cend(__n);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    float load_factor() const _NOEXCEPT {return __table_.load_factor();}
+    _LIBCPP_INLINE_VISIBILITY
+    float max_load_factor() const _NOEXCEPT {return __table_.max_load_factor();}
+    _LIBCPP_INLINE_VISIBILITY
+    void max_load_factor(float __mlf) {__table_.max_load_factor(__mlf);}
+    _LIBCPP_INLINE_VISIBILITY
+    void rehash(size_type __n) {__table_.rehash(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    void reserve(size_type __n) {__table_.reserve(__n);}
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+    bool __dereferenceable(const const_iterator* __i) const
+        {return __table_.__dereferenceable(_VSTD::addressof(__i->__i_));}
+    bool __decrementable(const const_iterator* __i) const
+        {return __table_.__decrementable(_VSTD::addressof(__i->__i_));}
+    bool __addable(const const_iterator* __i, ptrdiff_t __n) const
+        {return __table_.__addable(_VSTD::addressof(__i->__i_), __n);}
+    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const
+        {return __table_.__addable(_VSTD::addressof(__i->__i_), __n);}
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+private:
+
+#ifdef _LIBCPP_CXX03_LANG
+    __node_holder __construct_node_with_key(const key_type& __k);
+#endif
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator,
+         class _Hash = hash<__iter_key_type<_InputIterator>>,
+         class _Pred = equal_to<__iter_key_type<_InputIterator>>,
+         class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<!__is_allocator<_Pred>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_map(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type = 0,
+              _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
+  -> unordered_map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>, _Hash, _Pred, _Allocator>;
+
+template<class _Key, class _Tp, class _Hash = hash<remove_const_t<_Key>>,
+         class _Pred = equal_to<remove_const_t<_Key>>,
+         class _Allocator = allocator<pair<const _Key, _Tp>>,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<!__is_allocator<_Pred>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_map(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type = 0,
+              _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
+  -> unordered_map<remove_const_t<_Key>, _Tp, _Hash, _Pred, _Allocator>;
+
+template<class _InputIterator, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_map(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Allocator)
+  -> unordered_map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
+                   hash<__iter_key_type<_InputIterator>>, equal_to<__iter_key_type<_InputIterator>>, _Allocator>;
+
+template<class _InputIterator, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_map(_InputIterator, _InputIterator, _Allocator)
+  -> unordered_map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
+                   hash<__iter_key_type<_InputIterator>>, equal_to<__iter_key_type<_InputIterator>>, _Allocator>;
+
+template<class _InputIterator, class _Hash, class _Allocator,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_map(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
+  -> unordered_map<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
+                   _Hash, equal_to<__iter_key_type<_InputIterator>>, _Allocator>;
+
+template<class _Key, class _Tp, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_map(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type, _Allocator)
+  -> unordered_map<remove_const_t<_Key>, _Tp,
+                   hash<remove_const_t<_Key>>,
+                   equal_to<remove_const_t<_Key>>, _Allocator>;
+
+template<class _Key, class _Tp, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_map(initializer_list<pair<_Key, _Tp>>, _Allocator)
+  -> unordered_map<remove_const_t<_Key>, _Tp,
+                   hash<remove_const_t<_Key>>,
+                   equal_to<remove_const_t<_Key>>, _Allocator>;
+
+template<class _Key, class _Tp, class _Hash, class _Allocator,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_map(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
+  -> unordered_map<remove_const_t<_Key>, _Tp, _Hash,
+                   equal_to<remove_const_t<_Key>>, _Allocator>;
+#endif
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
+        size_type __n, const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
+        size_type __n, const hasher& __hf, const key_equal& __eql,
+        const allocator_type& __a)
+    : __table_(__hf, __eql, typename __table::allocator_type(__a))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
+        const allocator_type& __a)
+    : __table_(typename __table::allocator_type(__a))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
+        _InputIterator __first, _InputIterator __last)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    insert(__first, __last);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, typename __table::allocator_type(__a))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
+        const unordered_map& __u)
+    : __table_(__u.__table_)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__u.bucket_count());
+    insert(__u.begin(), __u.end());
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
+        const unordered_map& __u, const allocator_type& __a)
+    : __table_(__u.__table_, typename __table::allocator_type(__a))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__u.bucket_count());
+    insert(__u.begin(), __u.end());
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
+        unordered_map&& __u)
+    _NOEXCEPT_(is_nothrow_move_constructible<__table>::value)
+    : __table_(_VSTD::move(__u.__table_))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+    __get_db()->swap(this, &__u);
+#endif
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
+        unordered_map&& __u, const allocator_type& __a)
+    : __table_(_VSTD::move(__u.__table_), typename __table::allocator_type(__a))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    if (__a != __u.get_allocator())
+    {
+        iterator __i = __u.begin();
+        while (__u.size() != 0) {
+            __table_.__emplace_unique(
+                __u.__table_.remove((__i++).__i_)->__value_.__move());
+        }
+    }
+#if _LIBCPP_DEBUG_LEVEL == 2
+    else
+        __get_db()->swap(this, &__u);
+#endif
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
+        initializer_list<value_type> __il)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    insert(__il.begin(), __il.end());
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
+        initializer_list<value_type> __il, size_type __n, const hasher& __hf,
+        const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__il.begin(), __il.end());
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_map(
+        initializer_list<value_type> __il, size_type __n, const hasher& __hf,
+        const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, typename __table::allocator_type(__a))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__il.begin(), __il.end());
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>&
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator=(unordered_map&& __u)
+    _NOEXCEPT_(is_nothrow_move_assignable<__table>::value)
+{
+    __table_ = _VSTD::move(__u.__table_);
+    return *this;
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>&
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator=(
+        initializer_list<value_type> __il)
+{
+    __table_.__assign_unique(__il.begin(), __il.end());
+    return *this;
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+inline
+void
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::insert(_InputIterator __first,
+                                                       _InputIterator __last)
+{
+    for (; __first != __last; ++__first)
+        __table_.__insert_unique(*__first);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+_Tp&
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](const key_type& __k)
+{
+    return __table_.__emplace_unique_key_args(__k,
+        piecewise_construct, _VSTD::forward_as_tuple(__k),
+                             _VSTD::forward_as_tuple()).first->__get_value().second;
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+_Tp&
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](key_type&& __k)
+{
+    return __table_.__emplace_unique_key_args(__k,
+        piecewise_construct, _VSTD::forward_as_tuple(_VSTD::move(__k)),
+                             _VSTD::forward_as_tuple()).first->__get_value().second;
+}
+#else // _LIBCPP_CXX03_LANG
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+typename unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::__node_holder
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::__construct_node_with_key(const key_type& __k)
+{
+    __node_allocator& __na = __table_.__node_alloc();
+    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
+    __node_traits::construct(__na, _VSTD::addressof(__h->__value_.__get_value().first), __k);
+    __h.get_deleter().__first_constructed = true;
+    __node_traits::construct(__na, _VSTD::addressof(__h->__value_.__get_value().second));
+    __h.get_deleter().__second_constructed = true;
+    return __h;
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+_Tp&
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::operator[](const key_type& __k)
+{
+    iterator __i = find(__k);
+    if (__i != end())
+        return __i->second;
+    __node_holder __h = __construct_node_with_key(__k);
+    pair<iterator, bool> __r = __table_.__node_insert_unique(__h.get());
+    __h.release();
+    return __r.first->second;
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+_Tp&
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::at(const key_type& __k)
+{
+    iterator __i = find(__k);
+    if (__i == end())
+        __throw_out_of_range("unordered_map::at: key not found");
+    return __i->second;
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+const _Tp&
+unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::at(const key_type& __k) const
+{
+    const_iterator __i = find(__k);
+    if (__i == end())
+        __throw_out_of_range("unordered_map::at: key not found");
+    return __i->second;
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+     unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc,
+          class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+    typename unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::size_type
+    erase_if(unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __c,
+             _Predicate __pred) {
+  return _VSTD::__libcpp_erase_if_container(__c, __pred);
+}
+#endif
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+bool
+operator==(const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+           const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+{
+    if (__x.size() != __y.size())
+        return false;
+    typedef typename unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>::const_iterator
+                                                                 const_iterator;
+    for (const_iterator __i = __x.begin(), __ex = __x.end(), __ey = __y.end();
+            __i != __ex; ++__i)
+    {
+        const_iterator __j = __y.find(__i->first);
+        if (__j == __ey || !(*__i == *__j))
+            return false;
+    }
+    return true;
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+           const unordered_map<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Key, class _Tp, class _Hash = hash<_Key>, class _Pred = equal_to<_Key>,
+          class _Alloc = allocator<pair<const _Key, _Tp> > >
+class _LIBCPP_TEMPLATE_VIS unordered_multimap
+{
+public:
+    // types
+    typedef _Key                                           key_type;
+    typedef _Tp                                            mapped_type;
+    typedef __identity_t<_Hash>                            hasher;
+    typedef __identity_t<_Pred>                            key_equal;
+    typedef __identity_t<_Alloc>                           allocator_type;
+    typedef pair<const key_type, mapped_type>              value_type;
+    typedef value_type&                                    reference;
+    typedef const value_type&                              const_reference;
+    static_assert((is_same<value_type, typename allocator_type::value_type>::value),
+                  "Invalid allocator::value_type");
+
+private:
+    typedef __hash_value_type<key_type, mapped_type>                          __value_type;
+    typedef __unordered_map_hasher<key_type, __value_type, hasher, key_equal> __hasher;
+    typedef __unordered_map_equal<key_type, __value_type, key_equal, hasher>  __key_equal;
+    typedef typename __rebind_alloc_helper<allocator_traits<allocator_type>,
+                                                 __value_type>::type          __allocator_type;
+
+    typedef __hash_table<__value_type, __hasher,
+                         __key_equal,  __allocator_type>   __table;
+
+    __table __table_;
+
+    typedef typename __table::_NodeTypes                   _NodeTypes;
+    typedef typename __table::__node_traits                __node_traits;
+    typedef typename __table::__node_allocator             __node_allocator;
+    typedef typename __table::__node                       __node;
+    typedef __hash_map_node_destructor<__node_allocator>   _Dp;
+    typedef unique_ptr<__node, _Dp>                         __node_holder;
+    typedef allocator_traits<allocator_type>               __alloc_traits;
+    static_assert((is_same<typename __node_traits::size_type,
+                          typename __alloc_traits::size_type>::value),
+                 "Allocator uses different size_type for different types");
+public:
+    typedef typename __alloc_traits::pointer         pointer;
+    typedef typename __alloc_traits::const_pointer   const_pointer;
+    typedef typename __table::size_type              size_type;
+    typedef typename __table::difference_type        difference_type;
+
+    typedef __hash_map_iterator<typename __table::iterator>       iterator;
+    typedef __hash_map_const_iterator<typename __table::const_iterator> const_iterator;
+    typedef __hash_map_iterator<typename __table::local_iterator> local_iterator;
+    typedef __hash_map_const_iterator<typename __table::const_local_iterator> const_local_iterator;
+
+#if _LIBCPP_STD_VER > 14
+    typedef __map_node_handle<__node, allocator_type> node_type;
+#endif
+
+    template <class _Key2, class _Tp2, class _Hash2, class _Pred2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS unordered_map;
+    template <class _Key2, class _Tp2, class _Hash2, class _Pred2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
+
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_multimap()
+        _NOEXCEPT_(is_nothrow_default_constructible<__table>::value)
+        {
+#if _LIBCPP_DEBUG_LEVEL == 2
+            __get_db()->__insert_c(this);
+#endif
+        }
+    explicit unordered_multimap(size_type __n, const hasher& __hf = hasher(),
+                                const key_equal& __eql = key_equal());
+    unordered_multimap(size_type __n, const hasher& __hf,
+                                const key_equal& __eql,
+                                const allocator_type& __a);
+    template <class _InputIterator>
+        unordered_multimap(_InputIterator __first, _InputIterator __last);
+    template <class _InputIterator>
+        unordered_multimap(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf = hasher(),
+                      const key_equal& __eql = key_equal());
+    template <class _InputIterator>
+        unordered_multimap(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf,
+                      const key_equal& __eql,
+                      const allocator_type& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    explicit unordered_multimap(const allocator_type& __a);
+    unordered_multimap(const unordered_multimap& __u);
+    unordered_multimap(const unordered_multimap& __u, const allocator_type& __a);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_multimap(unordered_multimap&& __u)
+        _NOEXCEPT_(is_nothrow_move_constructible<__table>::value);
+    unordered_multimap(unordered_multimap&& __u, const allocator_type& __a);
+    unordered_multimap(initializer_list<value_type> __il);
+    unordered_multimap(initializer_list<value_type> __il, size_type __n,
+                       const hasher& __hf = hasher(),
+                       const key_equal& __eql = key_equal());
+    unordered_multimap(initializer_list<value_type> __il, size_type __n,
+                       const hasher& __hf, const key_equal& __eql,
+                       const allocator_type& __a);
+#endif // _LIBCPP_CXX03_LANG
+#if _LIBCPP_STD_VER > 11
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_multimap(size_type __n, const allocator_type& __a)
+      : unordered_multimap(__n, hasher(), key_equal(), __a) {}
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_multimap(size_type __n, const hasher& __hf, const allocator_type& __a)
+      : unordered_multimap(__n, __hf, key_equal(), __a) {}
+    template <class _InputIterator>
+    _LIBCPP_INLINE_VISIBILITY
+      unordered_multimap(_InputIterator __first, _InputIterator __last, size_type __n, const allocator_type& __a)
+      : unordered_multimap(__first, __last, __n, hasher(), key_equal(), __a) {}
+    template <class _InputIterator>
+    _LIBCPP_INLINE_VISIBILITY
+      unordered_multimap(_InputIterator __first, _InputIterator __last, size_type __n, const hasher& __hf,
+        const allocator_type& __a)
+      : unordered_multimap(__first, __last, __n, __hf, key_equal(), __a) {}
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_multimap(initializer_list<value_type> __il, size_type __n, const allocator_type& __a)
+      : unordered_multimap(__il, __n, hasher(), key_equal(), __a) {}
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_multimap(initializer_list<value_type> __il, size_type __n, const hasher& __hf,
+      const allocator_type& __a)
+      : unordered_multimap(__il, __n, __hf, key_equal(), __a) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    ~unordered_multimap() {
+        static_assert(sizeof(__diagnose_unordered_container_requirements<_Key, _Hash, _Pred>(0)), "");
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_multimap& operator=(const unordered_multimap& __u)
+    {
+#ifndef _LIBCPP_CXX03_LANG
+        __table_ = __u.__table_;
+#else
+        if (this != _VSTD::addressof(__u)) {
+            __table_.clear();
+            __table_.hash_function() = __u.__table_.hash_function();
+            __table_.key_eq() = __u.__table_.key_eq();
+            __table_.max_load_factor() = __u.__table_.max_load_factor();
+            __table_.__copy_assign_alloc(__u.__table_);
+            insert(__u.begin(), __u.end());
+        }
+#endif
+        return *this;
+    }
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_multimap& operator=(unordered_multimap&& __u)
+        _NOEXCEPT_(is_nothrow_move_assignable<__table>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_multimap& operator=(initializer_list<value_type> __il);
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT
+        {return allocator_type(__table_.__node_alloc());}
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool      empty() const _NOEXCEPT {return __table_.size() == 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT  {return __table_.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT {return __table_.max_size();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       begin() _NOEXCEPT        {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       end() _NOEXCEPT          {return __table_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin()  const _NOEXCEPT {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()    const _NOEXCEPT {return __table_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin() const _NOEXCEPT {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend()   const _NOEXCEPT {return __table_.end();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const value_type& __x) {return __table_.__insert_multi(__x);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, const value_type& __x)
+        {return __table_.__insert_multi(__p.__i_, __x);}
+
+    template <class _InputIterator>
+    _LIBCPP_INLINE_VISIBILITY
+    void insert(_InputIterator __first, _InputIterator __last);
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void insert(initializer_list<value_type> __il)
+        {insert(__il.begin(), __il.end());}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(value_type&& __x) {return __table_.__insert_multi(_VSTD::move(__x));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, value_type&& __x)
+        {return __table_.__insert_multi(__p.__i_, _VSTD::move(__x));}
+
+    template <class _Pp,
+              class = typename enable_if<is_constructible<value_type, _Pp>::value>::type>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(_Pp&& __x)
+        {return __table_.__insert_multi(_VSTD::forward<_Pp>(__x));}
+
+    template <class _Pp,
+              class = typename enable_if<is_constructible<value_type, _Pp>::value>::type>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, _Pp&& __x)
+        {return __table_.__insert_multi(__p.__i_, _VSTD::forward<_Pp>(__x));}
+
+    template <class... _Args>
+    iterator emplace(_Args&&... __args) {
+        return __table_.__emplace_multi(_VSTD::forward<_Args>(__args)...);
+    }
+
+    template <class... _Args>
+    iterator emplace_hint(const_iterator __p, _Args&&... __args) {
+        return __table_.__emplace_hint_multi(__p.__i_, _VSTD::forward<_Args>(__args)...);
+    }
+#endif // _LIBCPP_CXX03_LANG
+
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(const_iterator __p) {return __table_.erase(__p.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(iterator __p)       {return __table_.erase(__p.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type erase(const key_type& __k) {return __table_.__erase_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(const_iterator __first, const_iterator __last)
+        {return __table_.erase(__first.__i_, __last.__i_);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT {__table_.clear();}
+
+#if _LIBCPP_STD_VER > 14
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to unordered_multimap::insert()");
+        return __table_.template __node_handle_insert_multi<node_type>(
+            _VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __hint, node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to unordered_multimap::insert()");
+        return __table_.template __node_handle_insert_multi<node_type>(
+            __hint.__i_, _VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(key_type const& __key)
+    {
+        return __table_.template __node_handle_extract<node_type>(__key);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(const_iterator __it)
+    {
+        return __table_.template __node_handle_extract<node_type>(
+            __it.__i_);
+    }
+
+    template <class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_multimap<key_type, mapped_type, _H2, _P2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __table_.__node_handle_merge_multi(__source.__table_);
+    }
+    template <class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_multimap<key_type, mapped_type, _H2, _P2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __table_.__node_handle_merge_multi(__source.__table_);
+    }
+    template <class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_map<key_type, mapped_type, _H2, _P2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __table_.__node_handle_merge_multi(__source.__table_);
+    }
+    template <class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_map<key_type, mapped_type, _H2, _P2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __table_.__node_handle_merge_multi(__source.__table_);
+    }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(unordered_multimap& __u)
+        _NOEXCEPT_(__is_nothrow_swappable<__table>::value)
+        {__table_.swap(__u.__table_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    hasher hash_function() const
+        {return __table_.hash_function().hash_function();}
+    _LIBCPP_INLINE_VISIBILITY
+    key_equal key_eq() const
+        {return __table_.key_eq().key_eq();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       find(const key_type& __k)       {return __table_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const key_type& __k) const {return __table_.find(__k);}
+#if _LIBCPP_STD_VER > 17
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       find(const _K2& __k)            {return __table_.find(__k);}
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const _K2& __k) const      {return __table_.find(__k);}
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type count(const key_type& __k) const {return __table_.__count_multi(__k);}
+#if _LIBCPP_STD_VER > 17
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    size_type count(const _K2& __k) const      {return __table_.__count_multi(__k);}
+#endif // _LIBCPP_STD_VER > 17
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const key_type& __k) const {return find(__k) != end();}
+
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const _K2& __k) const      {return find(__k) != end();}
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, iterator>             equal_range(const key_type& __k)
+        {return __table_.__equal_range_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    pair<const_iterator, const_iterator> equal_range(const key_type& __k) const
+        {return __table_.__equal_range_multi(__k);}
+#if _LIBCPP_STD_VER > 17
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, iterator>             equal_range(const _K2& __k)
+        {return __table_.__equal_range_multi(__k);}
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<const_iterator, const_iterator> equal_range(const _K2& __k) const
+        {return __table_.__equal_range_multi(__k);}
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket_count() const _NOEXCEPT {return __table_.bucket_count();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_bucket_count() const _NOEXCEPT
+        {return __table_.max_bucket_count();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket_size(size_type __n) const
+        {return __table_.bucket_size(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket(const key_type& __k) const {return __table_.bucket(__k);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    local_iterator       begin(size_type __n)        {return __table_.begin(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    local_iterator       end(size_type __n)          {return __table_.end(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator begin(size_type __n) const  {return __table_.cbegin(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator end(size_type __n) const    {return __table_.cend(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator cbegin(size_type __n) const {return __table_.cbegin(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator cend(size_type __n) const   {return __table_.cend(__n);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    float load_factor() const _NOEXCEPT {return __table_.load_factor();}
+    _LIBCPP_INLINE_VISIBILITY
+    float max_load_factor() const _NOEXCEPT {return __table_.max_load_factor();}
+    _LIBCPP_INLINE_VISIBILITY
+    void max_load_factor(float __mlf) {__table_.max_load_factor(__mlf);}
+    _LIBCPP_INLINE_VISIBILITY
+    void rehash(size_type __n) {__table_.rehash(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    void reserve(size_type __n) {__table_.reserve(__n);}
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+    bool __dereferenceable(const const_iterator* __i) const
+        {return __table_.__dereferenceable(_VSTD::addressof(__i->__i_));}
+    bool __decrementable(const const_iterator* __i) const
+        {return __table_.__decrementable(_VSTD::addressof(__i->__i_));}
+    bool __addable(const const_iterator* __i, ptrdiff_t __n) const
+        {return __table_.__addable(_VSTD::addressof(__i->__i_), __n);}
+    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const
+        {return __table_.__addable(_VSTD::addressof(__i->__i_), __n);}
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator,
+         class _Hash = hash<__iter_key_type<_InputIterator>>,
+         class _Pred = equal_to<__iter_key_type<_InputIterator>>,
+         class _Allocator = allocator<__iter_to_alloc_type<_InputIterator>>,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<!__is_allocator<_Pred>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multimap(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type = 0,
+                   _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
+  -> unordered_multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>, _Hash, _Pred, _Allocator>;
+
+template<class _Key, class _Tp, class _Hash = hash<remove_const_t<_Key>>,
+         class _Pred = equal_to<remove_const_t<_Key>>,
+         class _Allocator = allocator<pair<const _Key, _Tp>>,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<!__is_allocator<_Pred>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multimap(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type = 0,
+                   _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
+  -> unordered_multimap<remove_const_t<_Key>, _Tp, _Hash, _Pred, _Allocator>;
+
+template<class _InputIterator, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multimap(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Allocator)
+  -> unordered_multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
+                        hash<__iter_key_type<_InputIterator>>, equal_to<__iter_key_type<_InputIterator>>, _Allocator>;
+
+template<class _InputIterator, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multimap(_InputIterator, _InputIterator, _Allocator)
+  -> unordered_multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
+                        hash<__iter_key_type<_InputIterator>>, equal_to<__iter_key_type<_InputIterator>>, _Allocator>;
+
+template<class _InputIterator, class _Hash, class _Allocator,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multimap(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
+  -> unordered_multimap<__iter_key_type<_InputIterator>, __iter_mapped_type<_InputIterator>,
+                        _Hash, equal_to<__iter_key_type<_InputIterator>>, _Allocator>;
+
+template<class _Key, class _Tp, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multimap(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type, _Allocator)
+  -> unordered_multimap<remove_const_t<_Key>, _Tp,
+                        hash<remove_const_t<_Key>>,
+                        equal_to<remove_const_t<_Key>>, _Allocator>;
+
+template<class _Key, class _Tp, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multimap(initializer_list<pair<_Key, _Tp>>, _Allocator)
+  -> unordered_multimap<remove_const_t<_Key>, _Tp,
+                        hash<remove_const_t<_Key>>,
+                        equal_to<remove_const_t<_Key>>, _Allocator>;
+
+template<class _Key, class _Tp, class _Hash, class _Allocator,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multimap(initializer_list<pair<_Key, _Tp>>, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
+  -> unordered_multimap<remove_const_t<_Key>, _Tp, _Hash,
+                        equal_to<remove_const_t<_Key>>, _Allocator>;
+#endif
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
+        size_type __n, const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
+        size_type __n, const hasher& __hf, const key_equal& __eql,
+        const allocator_type& __a)
+    : __table_(__hf, __eql, typename __table::allocator_type(__a))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
+        _InputIterator __first, _InputIterator __last)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    insert(__first, __last);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, typename __table::allocator_type(__a))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
+        const allocator_type& __a)
+    : __table_(typename __table::allocator_type(__a))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
+        const unordered_multimap& __u)
+    : __table_(__u.__table_)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__u.bucket_count());
+    insert(__u.begin(), __u.end());
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
+        const unordered_multimap& __u, const allocator_type& __a)
+    : __table_(__u.__table_, typename __table::allocator_type(__a))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__u.bucket_count());
+    insert(__u.begin(), __u.end());
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
+        unordered_multimap&& __u)
+    _NOEXCEPT_(is_nothrow_move_constructible<__table>::value)
+    : __table_(_VSTD::move(__u.__table_))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+    __get_db()->swap(this, &__u);
+#endif
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
+        unordered_multimap&& __u, const allocator_type& __a)
+    : __table_(_VSTD::move(__u.__table_), typename __table::allocator_type(__a))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    if (__a != __u.get_allocator())
+    {
+        iterator __i = __u.begin();
+        while (__u.size() != 0)
+        {
+            __table_.__insert_multi(
+                __u.__table_.remove((__i++).__i_)->__value_.__move());
+        }
+    }
+#if _LIBCPP_DEBUG_LEVEL == 2
+    else
+        __get_db()->swap(this, &__u);
+#endif
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
+        initializer_list<value_type> __il)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    insert(__il.begin(), __il.end());
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
+        initializer_list<value_type> __il, size_type __n, const hasher& __hf,
+        const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__il.begin(), __il.end());
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::unordered_multimap(
+        initializer_list<value_type> __il, size_type __n, const hasher& __hf,
+        const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, typename __table::allocator_type(__a))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__il.begin(), __il.end());
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>&
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::operator=(unordered_multimap&& __u)
+    _NOEXCEPT_(is_nothrow_move_assignable<__table>::value)
+{
+    __table_ = _VSTD::move(__u.__table_);
+    return *this;
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>&
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::operator=(
+        initializer_list<value_type> __il)
+{
+    __table_.__assign_multi(__il.begin(), __il.end());
+    return *this;
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+inline
+void
+unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::insert(_InputIterator __first,
+                                                            _InputIterator __last)
+{
+    for (; __first != __last; ++__first)
+        __table_.__insert_multi(*__first);
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+     unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc,
+          class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+    typename unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::size_type
+    erase_if(unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __c,
+             _Predicate __pred) {
+  return _VSTD::__libcpp_erase_if_container(__c, __pred);
+}
+#endif
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+bool
+operator==(const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+           const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+{
+    if (__x.size() != __y.size())
+        return false;
+    typedef typename unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>::const_iterator
+                                                                 const_iterator;
+    typedef pair<const_iterator, const_iterator> _EqRng;
+    for (const_iterator __i = __x.begin(), __ex = __x.end(); __i != __ex;)
+    {
+        _EqRng __xeq = __x.equal_range(__i->first);
+        _EqRng __yeq = __y.equal_range(__i->first);
+        if (_VSTD::distance(__xeq.first, __xeq.second) !=
+            _VSTD::distance(__yeq.first, __yeq.second) ||
+                  !_VSTD::is_permutation(__xeq.first, __xeq.second, __yeq.first))
+            return false;
+        __i = __xeq.second;
+    }
+    return true;
+}
+
+template <class _Key, class _Tp, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __x,
+           const unordered_multimap<_Key, _Tp, _Hash, _Pred, _Alloc>& __y)
+{
+    return !(__x == __y);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_UNORDERED_MAP
diff --git a/contrib/libs/cxxsupp/libcxx/include/unordered_set b/contrib/libs/cxxsupp/libcxx/include/unordered_set
new file mode 100644
index 00000000000..5856e4bc401
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/unordered_set
@@ -0,0 +1,1777 @@
+// -*- C++ -*-
+//===-------------------------- unordered_set -----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_UNORDERED_SET
+#define _LIBCPP_UNORDERED_SET
+
+/*
+
+    unordered_set synopsis
+
+#include <initializer_list>
+
+namespace std
+{
+
+template <class Value, class Hash = hash<Value>, class Pred = equal_to<Value>,
+          class Alloc = allocator<Value>>
+class unordered_set
+{
+public:
+    // types
+    typedef Value                                                      key_type;
+    typedef key_type                                                   value_type;
+    typedef Hash                                                       hasher;
+    typedef Pred                                                       key_equal;
+    typedef Alloc                                                      allocator_type;
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    typedef typename allocator_traits<allocator_type>::pointer         pointer;
+    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
+    typedef typename allocator_traits<allocator_type>::size_type       size_type;
+    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
+
+    typedef /unspecified/ iterator;
+    typedef /unspecified/ const_iterator;
+    typedef /unspecified/ local_iterator;
+    typedef /unspecified/ const_local_iterator;
+
+    typedef unspecified node_type unspecified;                            // C++17
+    typedef INSERT_RETURN_TYPE<iterator, node_type> insert_return_type;   // C++17
+
+    unordered_set()
+        noexcept(
+            is_nothrow_default_constructible<hasher>::value &&
+            is_nothrow_default_constructible<key_equal>::value &&
+            is_nothrow_default_constructible<allocator_type>::value);
+    explicit unordered_set(size_type n, const hasher& hf = hasher(),
+                           const key_equal& eql = key_equal(),
+                           const allocator_type& a = allocator_type());
+    template <class InputIterator>
+        unordered_set(InputIterator f, InputIterator l,
+                      size_type n = 0, const hasher& hf = hasher(),
+                      const key_equal& eql = key_equal(),
+                      const allocator_type& a = allocator_type());
+    explicit unordered_set(const allocator_type&);
+    unordered_set(const unordered_set&);
+    unordered_set(const unordered_set&, const Allocator&);
+    unordered_set(unordered_set&&)
+        noexcept(
+            is_nothrow_move_constructible<hasher>::value &&
+            is_nothrow_move_constructible<key_equal>::value &&
+            is_nothrow_move_constructible<allocator_type>::value);
+    unordered_set(unordered_set&&, const Allocator&);
+    unordered_set(initializer_list<value_type>, size_type n = 0,
+                  const hasher& hf = hasher(), const key_equal& eql = key_equal(),
+                  const allocator_type& a = allocator_type());
+    unordered_set(size_type n, const allocator_type& a); // C++14
+    unordered_set(size_type n, const hasher& hf, const allocator_type& a); // C++14
+    template <class InputIterator>
+      unordered_set(InputIterator f, InputIterator l, size_type n, const allocator_type& a); // C++14
+    template <class InputIterator>
+      unordered_set(InputIterator f, InputIterator l, size_type n,
+                    const hasher& hf,  const allocator_type& a); // C++14
+    unordered_set(initializer_list<value_type> il, size_type n, const allocator_type& a); // C++14
+    unordered_set(initializer_list<value_type> il, size_type n,
+                  const hasher& hf,  const allocator_type& a); // C++14
+    ~unordered_set();
+    unordered_set& operator=(const unordered_set&);
+    unordered_set& operator=(unordered_set&&)
+        noexcept(
+            allocator_type::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<allocator_type>::value &&
+            is_nothrow_move_assignable<hasher>::value &&
+            is_nothrow_move_assignable<key_equal>::value);
+    unordered_set& operator=(initializer_list<value_type>);
+
+    allocator_type get_allocator() const noexcept;
+
+    bool      empty() const noexcept;
+    size_type size() const noexcept;
+    size_type max_size() const noexcept;
+
+    iterator       begin() noexcept;
+    iterator       end() noexcept;
+    const_iterator begin()  const noexcept;
+    const_iterator end()    const noexcept;
+    const_iterator cbegin() const noexcept;
+    const_iterator cend()   const noexcept;
+
+    template <class... Args>
+        pair<iterator, bool> emplace(Args&&... args);
+    template <class... Args>
+        iterator emplace_hint(const_iterator position, Args&&... args);
+    pair<iterator, bool> insert(const value_type& obj);
+    pair<iterator, bool> insert(value_type&& obj);
+    iterator insert(const_iterator hint, const value_type& obj);
+    iterator insert(const_iterator hint, value_type&& obj);
+    template <class InputIterator>
+        void insert(InputIterator first, InputIterator last);
+    void insert(initializer_list<value_type>);
+
+    node_type extract(const_iterator position);                       // C++17
+    node_type extract(const key_type& x);                             // C++17
+    insert_return_type insert(node_type&& nh);                        // C++17
+    iterator           insert(const_iterator hint, node_type&& nh);   // C++17
+
+    iterator erase(const_iterator position);
+    iterator erase(iterator position);  // C++14
+    size_type erase(const key_type& k);
+    iterator erase(const_iterator first, const_iterator last);
+    void clear() noexcept;
+
+    template<class H2, class P2>
+      void merge(unordered_set<Key, H2, P2, Allocator>& source);         // C++17
+    template<class H2, class P2>
+      void merge(unordered_set<Key, H2, P2, Allocator>&& source);        // C++17
+    template<class H2, class P2>
+      void merge(unordered_multiset<Key, H2, P2, Allocator>& source);    // C++17
+    template<class H2, class P2>
+      void merge(unordered_multiset<Key, H2, P2, Allocator>&& source);   // C++17
+
+    void swap(unordered_set&)
+       noexcept(allocator_traits<Allocator>::is_always_equal::value &&
+                 noexcept(swap(declval<hasher&>(), declval<hasher&>())) &&
+                 noexcept(swap(declval<key_equal&>(), declval<key_equal&>()))); // C++17
+
+    hasher hash_function() const;
+    key_equal key_eq() const;
+
+    iterator       find(const key_type& k);
+    const_iterator find(const key_type& k) const;
+    template<typename K>
+        iterator find(const K& x);              // C++20
+    template<typename K>
+        const_iterator find(const K& x) const;  // C++20
+    size_type count(const key_type& k) const;
+    template<typename K>
+        size_type count(const K& k) const; // C++20
+    bool contains(const key_type& k) const; // C++20
+    template<typename K>
+        bool contains(const K& k) const; // C++20
+    pair<iterator, iterator>             equal_range(const key_type& k);
+    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
+    template<typename K>
+        pair<iterator, iterator>             equal_range(const K& k); // C++20
+    template<typename K>
+        pair<const_iterator, const_iterator> equal_range(const K& k) const; // C++20
+
+    size_type bucket_count() const noexcept;
+    size_type max_bucket_count() const noexcept;
+
+    size_type bucket_size(size_type n) const;
+    size_type bucket(const key_type& k) const;
+
+    local_iterator       begin(size_type n);
+    local_iterator       end(size_type n);
+    const_local_iterator begin(size_type n) const;
+    const_local_iterator end(size_type n) const;
+    const_local_iterator cbegin(size_type n) const;
+    const_local_iterator cend(size_type n) const;
+
+    float load_factor() const noexcept;
+    float max_load_factor() const noexcept;
+    void max_load_factor(float z);
+    void rehash(size_type n);
+    void reserve(size_type n);
+};
+
+template <class Value, class Hash, class Pred, class Alloc>
+    void swap(unordered_set<Value, Hash, Pred, Alloc>& x,
+              unordered_set<Value, Hash, Pred, Alloc>& y)
+              noexcept(noexcept(x.swap(y)));
+
+template <class Value, class Hash, class Pred, class Alloc>
+    bool
+    operator==(const unordered_set<Value, Hash, Pred, Alloc>& x,
+               const unordered_set<Value, Hash, Pred, Alloc>& y);
+
+template <class Value, class Hash, class Pred, class Alloc>
+    bool
+    operator!=(const unordered_set<Value, Hash, Pred, Alloc>& x,
+               const unordered_set<Value, Hash, Pred, Alloc>& y);
+
+template <class Value, class Hash = hash<Value>, class Pred = equal_to<Value>,
+          class Alloc = allocator<Value>>
+class unordered_multiset
+{
+public:
+    // types
+    typedef Value                                                      key_type;
+    typedef key_type                                                   value_type;
+    typedef Hash                                                       hasher;
+    typedef Pred                                                       key_equal;
+    typedef Alloc                                                      allocator_type;
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    typedef typename allocator_traits<allocator_type>::pointer         pointer;
+    typedef typename allocator_traits<allocator_type>::const_pointer   const_pointer;
+    typedef typename allocator_traits<allocator_type>::size_type       size_type;
+    typedef typename allocator_traits<allocator_type>::difference_type difference_type;
+
+    typedef /unspecified/ iterator;
+    typedef /unspecified/ const_iterator;
+    typedef /unspecified/ local_iterator;
+    typedef /unspecified/ const_local_iterator;
+
+    typedef unspecified node_type unspecified;   // C++17
+
+    unordered_multiset()
+        noexcept(
+            is_nothrow_default_constructible<hasher>::value &&
+            is_nothrow_default_constructible<key_equal>::value &&
+            is_nothrow_default_constructible<allocator_type>::value);
+    explicit unordered_multiset(size_type n, const hasher& hf = hasher(),
+                           const key_equal& eql = key_equal(),
+                           const allocator_type& a = allocator_type());
+    template <class InputIterator>
+        unordered_multiset(InputIterator f, InputIterator l,
+                      size_type n = 0, const hasher& hf = hasher(),
+                      const key_equal& eql = key_equal(),
+                      const allocator_type& a = allocator_type());
+    explicit unordered_multiset(const allocator_type&);
+    unordered_multiset(const unordered_multiset&);
+    unordered_multiset(const unordered_multiset&, const Allocator&);
+    unordered_multiset(unordered_multiset&&)
+        noexcept(
+            is_nothrow_move_constructible<hasher>::value &&
+            is_nothrow_move_constructible<key_equal>::value &&
+            is_nothrow_move_constructible<allocator_type>::value);
+    unordered_multiset(unordered_multiset&&, const Allocator&);
+    unordered_multiset(initializer_list<value_type>, size_type n = /see below/,
+                  const hasher& hf = hasher(), const key_equal& eql = key_equal(),
+                  const allocator_type& a = allocator_type());
+    unordered_multiset(size_type n, const allocator_type& a); // C++14
+    unordered_multiset(size_type n, const hasher& hf, const allocator_type& a); // C++14
+    template <class InputIterator>
+      unordered_multiset(InputIterator f, InputIterator l, size_type n, const allocator_type& a); // C++14
+    template <class InputIterator>
+      unordered_multiset(InputIterator f, InputIterator l, size_type n,
+                         const hasher& hf, const allocator_type& a); // C++14
+    unordered_multiset(initializer_list<value_type> il, size_type n, const allocator_type& a); // C++14
+    unordered_multiset(initializer_list<value_type> il, size_type n,
+                       const hasher& hf,  const allocator_type& a); // C++14
+    ~unordered_multiset();
+    unordered_multiset& operator=(const unordered_multiset&);
+    unordered_multiset& operator=(unordered_multiset&&)
+        noexcept(
+            allocator_type::propagate_on_container_move_assignment::value &&
+            is_nothrow_move_assignable<allocator_type>::value &&
+            is_nothrow_move_assignable<hasher>::value &&
+            is_nothrow_move_assignable<key_equal>::value);
+    unordered_multiset& operator=(initializer_list<value_type>);
+
+    allocator_type get_allocator() const noexcept;
+
+    bool      empty() const noexcept;
+    size_type size() const noexcept;
+    size_type max_size() const noexcept;
+
+    iterator       begin() noexcept;
+    iterator       end() noexcept;
+    const_iterator begin()  const noexcept;
+    const_iterator end()    const noexcept;
+    const_iterator cbegin() const noexcept;
+    const_iterator cend()   const noexcept;
+
+    template <class... Args>
+        iterator emplace(Args&&... args);
+    template <class... Args>
+        iterator emplace_hint(const_iterator position, Args&&... args);
+    iterator insert(const value_type& obj);
+    iterator insert(value_type&& obj);
+    iterator insert(const_iterator hint, const value_type& obj);
+    iterator insert(const_iterator hint, value_type&& obj);
+    template <class InputIterator>
+        void insert(InputIterator first, InputIterator last);
+    void insert(initializer_list<value_type>);
+
+    node_type extract(const_iterator position);             // C++17
+    node_type extract(const key_type& x);                   // C++17
+    iterator insert(node_type&& nh);                        // C++17
+    iterator insert(const_iterator hint, node_type&& nh);   // C++17
+
+    iterator erase(const_iterator position);
+    iterator erase(iterator position);  // C++14
+    size_type erase(const key_type& k);
+    iterator erase(const_iterator first, const_iterator last);
+    void clear() noexcept;
+
+    template<class H2, class P2>
+      void merge(unordered_multiset<Key, H2, P2, Allocator>& source);    // C++17
+    template<class H2, class P2>
+      void merge(unordered_multiset<Key, H2, P2, Allocator>&& source);   // C++17
+    template<class H2, class P2>
+      void merge(unordered_set<Key, H2, P2, Allocator>& source);         // C++17
+    template<class H2, class P2>
+      void merge(unordered_set<Key, H2, P2, Allocator>&& source);        // C++17
+
+    void swap(unordered_multiset&)
+       noexcept(allocator_traits<Allocator>::is_always_equal::value &&
+                 noexcept(swap(declval<hasher&>(), declval<hasher&>())) &&
+                 noexcept(swap(declval<key_equal&>(), declval<key_equal&>()))); // C++17
+
+    hasher hash_function() const;
+    key_equal key_eq() const;
+
+    iterator       find(const key_type& k);
+    const_iterator find(const key_type& k) const;
+    template<typename K>
+        iterator find(const K& x);              // C++20
+    template<typename K>
+        const_iterator find(const K& x) const;  // C++20
+    size_type count(const key_type& k) const;
+    template<typename K>
+        size_type count(const K& k) const; // C++20
+    bool contains(const key_type& k) const; // C++20
+    template<typename K>
+        bool contains(const K& k) const; // C++20
+    pair<iterator, iterator>             equal_range(const key_type& k);
+    pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
+    template<typename K>
+        pair<iterator, iterator>             equal_range(const K& k); // C++20
+    template<typename K>
+        pair<const_iterator, const_iterator> equal_range(const K& k) const; // C++20
+
+    size_type bucket_count() const noexcept;
+    size_type max_bucket_count() const noexcept;
+
+    size_type bucket_size(size_type n) const;
+    size_type bucket(const key_type& k) const;
+
+    local_iterator       begin(size_type n);
+    local_iterator       end(size_type n);
+    const_local_iterator begin(size_type n) const;
+    const_local_iterator end(size_type n) const;
+    const_local_iterator cbegin(size_type n) const;
+    const_local_iterator cend(size_type n) const;
+
+    float load_factor() const noexcept;
+    float max_load_factor() const noexcept;
+    void max_load_factor(float z);
+    void rehash(size_type n);
+    void reserve(size_type n);
+};
+
+template <class Value, class Hash, class Pred, class Alloc>
+    void swap(unordered_multiset<Value, Hash, Pred, Alloc>& x,
+              unordered_multiset<Value, Hash, Pred, Alloc>& y)
+              noexcept(noexcept(x.swap(y)));
+
+template <class K, class T, class H, class P, class A, class Predicate>
+    typename unordered_set<K, T, H, P, A>::size_type
+    erase_if(unordered_set<K, T, H, P, A>& c, Predicate pred);       // C++20
+
+template <class K, class T, class H, class P, class A, class Predicate>
+    typename unordered_multiset<K, T, H, P, A>::size_type
+    erase_if(unordered_multiset<K, T, H, P, A>& c, Predicate pred);  // C++20
+
+
+template <class Value, class Hash, class Pred, class Alloc>
+    bool
+    operator==(const unordered_multiset<Value, Hash, Pred, Alloc>& x,
+               const unordered_multiset<Value, Hash, Pred, Alloc>& y);
+
+template <class Value, class Hash, class Pred, class Alloc>
+    bool
+    operator!=(const unordered_multiset<Value, Hash, Pred, Alloc>& x,
+               const unordered_multiset<Value, Hash, Pred, Alloc>& y);
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__functional/is_transparent.h>
+#include <__hash_table>
+#include <__node_handle>
+#include <__utility/forward.h>
+#include <compare>
+#include <functional>
+#include <iterator> // __libcpp_erase_if_container
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+class unordered_multiset;
+
+template <class _Value, class _Hash = hash<_Value>, class _Pred = equal_to<_Value>,
+          class _Alloc = allocator<_Value> >
+class _LIBCPP_TEMPLATE_VIS unordered_set
+{
+public:
+    // types
+    typedef _Value                                                     key_type;
+    typedef key_type                                                   value_type;
+    typedef __identity_t<_Hash>                                        hasher;
+    typedef __identity_t<_Pred>                                        key_equal;
+    typedef __identity_t<_Alloc>                                       allocator_type;
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    static_assert((is_same<value_type, typename allocator_type::value_type>::value),
+                  "Invalid allocator::value_type");
+
+private:
+    typedef __hash_table<value_type, hasher, key_equal, allocator_type> __table;
+
+    __table __table_;
+
+public:
+    typedef typename __table::pointer         pointer;
+    typedef typename __table::const_pointer   const_pointer;
+    typedef typename __table::size_type       size_type;
+    typedef typename __table::difference_type difference_type;
+
+    typedef typename __table::const_iterator       iterator;
+    typedef typename __table::const_iterator       const_iterator;
+    typedef typename __table::const_local_iterator local_iterator;
+    typedef typename __table::const_local_iterator const_local_iterator;
+
+#if _LIBCPP_STD_VER > 14
+    typedef __set_node_handle<typename __table::__node, allocator_type> node_type;
+    typedef __insert_return_type<iterator, node_type> insert_return_type;
+#endif
+
+    template <class _Value2, class _Hash2, class _Pred2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS unordered_set;
+    template <class _Value2, class _Hash2, class _Pred2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS unordered_multiset;
+
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_set()
+        _NOEXCEPT_(is_nothrow_default_constructible<__table>::value)
+        {
+#if _LIBCPP_DEBUG_LEVEL == 2
+            __get_db()->__insert_c(this);
+#endif
+        }
+    explicit unordered_set(size_type __n, const hasher& __hf = hasher(),
+                           const key_equal& __eql = key_equal());
+#if _LIBCPP_STD_VER > 11
+    inline _LIBCPP_INLINE_VISIBILITY
+    unordered_set(size_type __n, const allocator_type& __a)
+        : unordered_set(__n, hasher(), key_equal(), __a) {}
+    inline _LIBCPP_INLINE_VISIBILITY
+    unordered_set(size_type __n, const hasher& __hf, const allocator_type& __a)
+        : unordered_set(__n, __hf, key_equal(), __a) {}
+#endif
+    unordered_set(size_type __n, const hasher& __hf, const key_equal& __eql,
+                  const allocator_type& __a);
+    template <class _InputIterator>
+        unordered_set(_InputIterator __first, _InputIterator __last);
+    template <class _InputIterator>
+        unordered_set(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf = hasher(),
+                      const key_equal& __eql = key_equal());
+    template <class _InputIterator>
+        unordered_set(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf, const key_equal& __eql,
+                      const allocator_type& __a);
+#if _LIBCPP_STD_VER > 11
+    template <class _InputIterator>
+    inline _LIBCPP_INLINE_VISIBILITY
+        unordered_set(_InputIterator __first, _InputIterator __last,
+                    size_type __n, const allocator_type& __a)
+            : unordered_set(__first, __last, __n, hasher(), key_equal(), __a) {}
+    template <class _InputIterator>
+        unordered_set(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf, const allocator_type& __a)
+            : unordered_set(__first, __last, __n, __hf, key_equal(), __a) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit unordered_set(const allocator_type& __a);
+    unordered_set(const unordered_set& __u);
+    unordered_set(const unordered_set& __u, const allocator_type& __a);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_set(unordered_set&& __u)
+        _NOEXCEPT_(is_nothrow_move_constructible<__table>::value);
+    unordered_set(unordered_set&& __u, const allocator_type& __a);
+    unordered_set(initializer_list<value_type> __il);
+    unordered_set(initializer_list<value_type> __il, size_type __n,
+                  const hasher& __hf = hasher(),
+                  const key_equal& __eql = key_equal());
+    unordered_set(initializer_list<value_type> __il, size_type __n,
+                  const hasher& __hf, const key_equal& __eql,
+                  const allocator_type& __a);
+#if _LIBCPP_STD_VER > 11
+    inline _LIBCPP_INLINE_VISIBILITY
+    unordered_set(initializer_list<value_type> __il, size_type __n,
+                                                      const allocator_type& __a)
+        : unordered_set(__il, __n, hasher(), key_equal(), __a) {}
+    inline _LIBCPP_INLINE_VISIBILITY
+    unordered_set(initializer_list<value_type> __il, size_type __n,
+                                  const hasher& __hf, const allocator_type& __a)
+        : unordered_set(__il, __n, __hf, key_equal(), __a) {}
+#endif
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    ~unordered_set() {
+        static_assert(sizeof(__diagnose_unordered_container_requirements<_Value, _Hash, _Pred>(0)), "");
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_set& operator=(const unordered_set& __u)
+    {
+        __table_ = __u.__table_;
+        return *this;
+    }
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_set& operator=(unordered_set&& __u)
+        _NOEXCEPT_(is_nothrow_move_assignable<__table>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_set& operator=(initializer_list<value_type> __il);
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT
+        {return allocator_type(__table_.__node_alloc());}
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool      empty() const _NOEXCEPT {return __table_.size() == 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT  {return __table_.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT {return __table_.max_size();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       begin() _NOEXCEPT        {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       end() _NOEXCEPT          {return __table_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin()  const _NOEXCEPT {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()    const _NOEXCEPT {return __table_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin() const _NOEXCEPT {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend()   const _NOEXCEPT {return __table_.end();}
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        pair<iterator, bool> emplace(_Args&&... __args)
+            {return __table_.__emplace_unique(_VSTD::forward<_Args>(__args)...);}
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+#if _LIBCPP_DEBUG_LEVEL == 2
+        iterator emplace_hint(const_iterator __p, _Args&&... __args)
+        {
+            _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+                "unordered_set::emplace_hint(const_iterator, args...) called with an iterator not"
+                " referring to this unordered_set");
+            return __table_.__emplace_unique(_VSTD::forward<_Args>(__args)...).first;
+        }
+#else
+        iterator emplace_hint(const_iterator, _Args&&... __args)
+            {return __table_.__emplace_unique(_VSTD::forward<_Args>(__args)...).first;}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> insert(value_type&& __x)
+        {return __table_.__insert_unique(_VSTD::move(__x));}
+    _LIBCPP_INLINE_VISIBILITY
+#if _LIBCPP_DEBUG_LEVEL == 2
+    iterator insert(const_iterator __p, value_type&& __x)
+        {
+            _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+                "unordered_set::insert(const_iterator, value_type&&) called with an iterator not"
+                " referring to this unordered_set");
+            return insert(_VSTD::move(__x)).first;
+        }
+#else
+    iterator insert(const_iterator, value_type&& __x)
+        {return insert(_VSTD::move(__x)).first;}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    void insert(initializer_list<value_type> __il)
+        {insert(__il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, bool> insert(const value_type& __x)
+        {return __table_.__insert_unique(__x);}
+
+    _LIBCPP_INLINE_VISIBILITY
+#if _LIBCPP_DEBUG_LEVEL == 2
+    iterator insert(const_iterator __p, const value_type& __x)
+        {
+            _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
+                "unordered_set::insert(const_iterator, const value_type&) called with an iterator not"
+                " referring to this unordered_set");
+            return insert(__x).first;
+        }
+#else
+    iterator insert(const_iterator, const value_type& __x)
+        {return insert(__x).first;}
+#endif
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        void insert(_InputIterator __first, _InputIterator __last);
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(const_iterator __p) {return __table_.erase(__p);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type erase(const key_type& __k) {return __table_.__erase_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(const_iterator __first, const_iterator __last)
+        {return __table_.erase(__first, __last);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT {__table_.clear();}
+
+#if _LIBCPP_STD_VER > 14
+    _LIBCPP_INLINE_VISIBILITY
+    insert_return_type insert(node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to unordered_set::insert()");
+        return __table_.template __node_handle_insert_unique<
+            node_type, insert_return_type>(_VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __h, node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to unordered_set::insert()");
+        return __table_.template __node_handle_insert_unique<node_type>(
+            __h, _VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(key_type const& __key)
+    {
+        return __table_.template __node_handle_extract<node_type>(__key);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(const_iterator __it)
+    {
+        return __table_.template __node_handle_extract<node_type>(__it);
+    }
+
+    template<class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_set<key_type, _H2, _P2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __table_.__node_handle_merge_unique(__source.__table_);
+    }
+    template<class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_set<key_type, _H2, _P2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __table_.__node_handle_merge_unique(__source.__table_);
+    }
+    template<class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_multiset<key_type, _H2, _P2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __table_.__node_handle_merge_unique(__source.__table_);
+    }
+    template<class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_multiset<key_type, _H2, _P2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        __table_.__node_handle_merge_unique(__source.__table_);
+    }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(unordered_set& __u)
+        _NOEXCEPT_(__is_nothrow_swappable<__table>::value)
+        {__table_.swap(__u.__table_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    hasher hash_function() const {return __table_.hash_function();}
+    _LIBCPP_INLINE_VISIBILITY
+    key_equal key_eq() const {return __table_.key_eq();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       find(const key_type& __k)       {return __table_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const key_type& __k) const {return __table_.find(__k);}
+#if _LIBCPP_STD_VER > 17
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       find(const _K2& __k)            {return __table_.find(__k);}
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const _K2& __k) const      {return __table_.find(__k);}
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type count(const key_type& __k) const {return __table_.__count_unique(__k);}
+#if _LIBCPP_STD_VER > 17
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    size_type count(const _K2& __k) const      {return __table_.__count_unique(__k);}
+#endif // _LIBCPP_STD_VER > 17
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const key_type& __k) const {return find(__k) != end();}
+
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const _K2& __k) const      {return find(__k) != end();}
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, iterator>             equal_range(const key_type& __k)
+        {return __table_.__equal_range_unique(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    pair<const_iterator, const_iterator> equal_range(const key_type& __k) const
+        {return __table_.__equal_range_unique(__k);}
+#if _LIBCPP_STD_VER > 17
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, iterator>             equal_range(const _K2& __k)
+        {return __table_.__equal_range_unique(__k);}
+    template <class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<const_iterator, const_iterator> equal_range(const _K2& __k) const
+        {return __table_.__equal_range_unique(__k);}
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket_count() const _NOEXCEPT {return __table_.bucket_count();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_bucket_count() const _NOEXCEPT {return __table_.max_bucket_count();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket_size(size_type __n) const {return __table_.bucket_size(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket(const key_type& __k) const {return __table_.bucket(__k);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    local_iterator       begin(size_type __n)        {return __table_.begin(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    local_iterator       end(size_type __n)          {return __table_.end(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator begin(size_type __n) const  {return __table_.cbegin(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator end(size_type __n) const    {return __table_.cend(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator cbegin(size_type __n) const {return __table_.cbegin(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator cend(size_type __n) const   {return __table_.cend(__n);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    float load_factor() const _NOEXCEPT {return __table_.load_factor();}
+    _LIBCPP_INLINE_VISIBILITY
+    float max_load_factor() const _NOEXCEPT {return __table_.max_load_factor();}
+    _LIBCPP_INLINE_VISIBILITY
+    void max_load_factor(float __mlf) {__table_.max_load_factor(__mlf);}
+    _LIBCPP_INLINE_VISIBILITY
+    void rehash(size_type __n) {__table_.rehash(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    void reserve(size_type __n) {__table_.reserve(__n);}
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+    bool __dereferenceable(const const_iterator* __i) const
+        {return __table_.__dereferenceable(__i);}
+    bool __decrementable(const const_iterator* __i) const
+        {return __table_.__decrementable(__i);}
+    bool __addable(const const_iterator* __i, ptrdiff_t __n) const
+        {return __table_.__addable(__i, __n);}
+    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const
+        {return __table_.__addable(__i, __n);}
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator,
+         class _Hash = hash<__iter_value_type<_InputIterator>>,
+         class _Pred = equal_to<__iter_value_type<_InputIterator>>,
+         class _Allocator = allocator<__iter_value_type<_InputIterator>>,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<!__is_allocator<_Pred>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_set(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type = 0,
+              _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
+  -> unordered_set<__iter_value_type<_InputIterator>, _Hash, _Pred, _Allocator>;
+
+template<class _Tp, class _Hash = hash<_Tp>,
+         class _Pred = equal_to<_Tp>,
+         class _Allocator = allocator<_Tp>,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<!__is_allocator<_Pred>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_set(initializer_list<_Tp>, typename allocator_traits<_Allocator>::size_type = 0,
+              _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
+  -> unordered_set<_Tp, _Hash, _Pred, _Allocator>;
+
+template<class _InputIterator, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_set(_InputIterator, _InputIterator,
+              typename allocator_traits<_Allocator>::size_type, _Allocator)
+  -> unordered_set<__iter_value_type<_InputIterator>,
+                   hash<__iter_value_type<_InputIterator>>,
+                   equal_to<__iter_value_type<_InputIterator>>,
+                   _Allocator>;
+
+template<class _InputIterator, class _Hash, class _Allocator,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_set(_InputIterator, _InputIterator,
+              typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
+  -> unordered_set<__iter_value_type<_InputIterator>, _Hash,
+                   equal_to<__iter_value_type<_InputIterator>>,
+                   _Allocator>;
+
+template<class _Tp, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_set(initializer_list<_Tp>, typename allocator_traits<_Allocator>::size_type, _Allocator)
+  -> unordered_set<_Tp, hash<_Tp>, equal_to<_Tp>, _Allocator>;
+
+template<class _Tp, class _Hash, class _Allocator,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_set(initializer_list<_Tp>, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
+  -> unordered_set<_Tp, _Hash, equal_to<_Tp>, _Allocator>;
+#endif
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(size_type __n,
+        const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(size_type __n,
+        const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
+        _InputIterator __first, _InputIterator __last)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    insert(__first, __last);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
+        const allocator_type& __a)
+    : __table_(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
+        const unordered_set& __u)
+    : __table_(__u.__table_)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__u.bucket_count());
+    insert(__u.begin(), __u.end());
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
+        const unordered_set& __u, const allocator_type& __a)
+    : __table_(__u.__table_, __a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__u.bucket_count());
+    insert(__u.begin(), __u.end());
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
+        unordered_set&& __u)
+    _NOEXCEPT_(is_nothrow_move_constructible<__table>::value)
+    : __table_(_VSTD::move(__u.__table_))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+    __get_db()->swap(this, &__u);
+#endif
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
+        unordered_set&& __u, const allocator_type& __a)
+    : __table_(_VSTD::move(__u.__table_), __a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    if (__a != __u.get_allocator())
+    {
+        iterator __i = __u.begin();
+        while (__u.size() != 0)
+            __table_.__insert_unique(_VSTD::move(__u.__table_.remove(__i++)->__value_));
+    }
+#if _LIBCPP_DEBUG_LEVEL == 2
+    else
+        __get_db()->swap(this, &__u);
+#endif
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
+        initializer_list<value_type> __il)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    insert(__il.begin(), __il.end());
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
+        initializer_list<value_type> __il, size_type __n, const hasher& __hf,
+        const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__il.begin(), __il.end());
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set(
+        initializer_list<value_type> __il, size_type __n, const hasher& __hf,
+        const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__il.begin(), __il.end());
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_set<_Value, _Hash, _Pred, _Alloc>&
+unordered_set<_Value, _Hash, _Pred, _Alloc>::operator=(unordered_set&& __u)
+    _NOEXCEPT_(is_nothrow_move_assignable<__table>::value)
+{
+    __table_ = _VSTD::move(__u.__table_);
+    return *this;
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_set<_Value, _Hash, _Pred, _Alloc>&
+unordered_set<_Value, _Hash, _Pred, _Alloc>::operator=(
+        initializer_list<value_type> __il)
+{
+    __table_.__assign_unique(__il.begin(), __il.end());
+    return *this;
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+inline
+void
+unordered_set<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator __first,
+                                                    _InputIterator __last)
+{
+    for (; __first != __last; ++__first)
+        __table_.__insert_unique(*__first);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(unordered_set<_Value, _Hash, _Pred, _Alloc>& __x,
+     unordered_set<_Value, _Hash, _Pred, _Alloc>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Value, class _Hash, class _Pred, class _Alloc,
+          class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+    typename unordered_set<_Value, _Hash, _Pred, _Alloc>::size_type
+    erase_if(unordered_set<_Value, _Hash, _Pred, _Alloc>& __c,
+             _Predicate __pred) {
+  return _VSTD::__libcpp_erase_if_container(__c, __pred);
+}
+#endif
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+bool
+operator==(const unordered_set<_Value, _Hash, _Pred, _Alloc>& __x,
+           const unordered_set<_Value, _Hash, _Pred, _Alloc>& __y)
+{
+    if (__x.size() != __y.size())
+        return false;
+    typedef typename unordered_set<_Value, _Hash, _Pred, _Alloc>::const_iterator
+                                                                 const_iterator;
+    for (const_iterator __i = __x.begin(), __ex = __x.end(), __ey = __y.end();
+            __i != __ex; ++__i)
+    {
+        const_iterator __j = __y.find(*__i);
+        if (__j == __ey || !(*__i == *__j))
+            return false;
+    }
+    return true;
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const unordered_set<_Value, _Hash, _Pred, _Alloc>& __x,
+           const unordered_set<_Value, _Hash, _Pred, _Alloc>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Value, class _Hash = hash<_Value>, class _Pred = equal_to<_Value>,
+          class _Alloc = allocator<_Value> >
+class _LIBCPP_TEMPLATE_VIS unordered_multiset
+{
+public:
+    // types
+    typedef _Value                                                     key_type;
+    typedef key_type                                                   value_type;
+    typedef __identity_t<_Hash>                                        hasher;
+    typedef __identity_t<_Pred>                                        key_equal;
+    typedef __identity_t<_Alloc>                                       allocator_type;
+    typedef value_type&                                                reference;
+    typedef const value_type&                                          const_reference;
+    static_assert((is_same<value_type, typename allocator_type::value_type>::value),
+                  "Invalid allocator::value_type");
+
+private:
+    typedef __hash_table<value_type, hasher, key_equal, allocator_type> __table;
+
+    __table __table_;
+
+public:
+    typedef typename __table::pointer         pointer;
+    typedef typename __table::const_pointer   const_pointer;
+    typedef typename __table::size_type       size_type;
+    typedef typename __table::difference_type difference_type;
+
+    typedef typename __table::const_iterator       iterator;
+    typedef typename __table::const_iterator       const_iterator;
+    typedef typename __table::const_local_iterator local_iterator;
+    typedef typename __table::const_local_iterator const_local_iterator;
+
+#if _LIBCPP_STD_VER > 14
+    typedef __set_node_handle<typename __table::__node, allocator_type> node_type;
+#endif
+
+    template <class _Value2, class _Hash2, class _Pred2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS unordered_set;
+    template <class _Value2, class _Hash2, class _Pred2, class _Alloc2>
+        friend class _LIBCPP_TEMPLATE_VIS unordered_multiset;
+
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_multiset()
+        _NOEXCEPT_(is_nothrow_default_constructible<__table>::value)
+        {
+#if _LIBCPP_DEBUG_LEVEL == 2
+            __get_db()->__insert_c(this);
+#endif
+        }
+    explicit unordered_multiset(size_type __n, const hasher& __hf = hasher(),
+                                const key_equal& __eql = key_equal());
+    unordered_multiset(size_type __n, const hasher& __hf,
+                       const key_equal& __eql, const allocator_type& __a);
+#if _LIBCPP_STD_VER > 11
+    inline _LIBCPP_INLINE_VISIBILITY
+    unordered_multiset(size_type __n, const allocator_type& __a)
+        : unordered_multiset(__n, hasher(), key_equal(), __a) {}
+    inline _LIBCPP_INLINE_VISIBILITY
+    unordered_multiset(size_type __n, const hasher& __hf, const allocator_type& __a)
+        : unordered_multiset(__n, __hf, key_equal(), __a) {}
+#endif
+    template <class _InputIterator>
+        unordered_multiset(_InputIterator __first, _InputIterator __last);
+    template <class _InputIterator>
+        unordered_multiset(_InputIterator __first, _InputIterator __last,
+                      size_type __n, const hasher& __hf = hasher(),
+                      const key_equal& __eql = key_equal());
+    template <class _InputIterator>
+        unordered_multiset(_InputIterator __first, _InputIterator __last,
+                      size_type __n , const hasher& __hf,
+                      const key_equal& __eql, const allocator_type& __a);
+#if _LIBCPP_STD_VER > 11
+    template <class _InputIterator>
+    inline _LIBCPP_INLINE_VISIBILITY
+    unordered_multiset(_InputIterator __first, _InputIterator __last,
+                       size_type __n, const allocator_type& __a)
+        : unordered_multiset(__first, __last, __n, hasher(), key_equal(), __a) {}
+    template <class _InputIterator>
+    inline _LIBCPP_INLINE_VISIBILITY
+    unordered_multiset(_InputIterator __first, _InputIterator __last,
+                       size_type __n, const hasher& __hf, const allocator_type& __a)
+        : unordered_multiset(__first, __last, __n, __hf, key_equal(), __a) {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    explicit unordered_multiset(const allocator_type& __a);
+    unordered_multiset(const unordered_multiset& __u);
+    unordered_multiset(const unordered_multiset& __u, const allocator_type& __a);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_multiset(unordered_multiset&& __u)
+        _NOEXCEPT_(is_nothrow_move_constructible<__table>::value);
+    unordered_multiset(unordered_multiset&& __u, const allocator_type& __a);
+    unordered_multiset(initializer_list<value_type> __il);
+    unordered_multiset(initializer_list<value_type> __il, size_type __n,
+                       const hasher& __hf = hasher(),
+                       const key_equal& __eql = key_equal());
+    unordered_multiset(initializer_list<value_type> __il, size_type __n,
+                       const hasher& __hf, const key_equal& __eql,
+                       const allocator_type& __a);
+#if _LIBCPP_STD_VER > 11
+    inline _LIBCPP_INLINE_VISIBILITY
+    unordered_multiset(initializer_list<value_type> __il, size_type __n, const allocator_type& __a)
+      : unordered_multiset(__il, __n, hasher(), key_equal(), __a) {}
+    inline _LIBCPP_INLINE_VISIBILITY
+    unordered_multiset(initializer_list<value_type> __il, size_type __n, const hasher& __hf, const allocator_type& __a)
+      : unordered_multiset(__il, __n, __hf, key_equal(), __a) {}
+#endif
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    ~unordered_multiset() {
+        static_assert(sizeof(__diagnose_unordered_container_requirements<_Value, _Hash, _Pred>(0)), "");
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_multiset& operator=(const unordered_multiset& __u)
+    {
+        __table_ = __u.__table_;
+        return *this;
+    }
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    unordered_multiset& operator=(unordered_multiset&& __u)
+        _NOEXCEPT_(is_nothrow_move_assignable<__table>::value);
+    unordered_multiset& operator=(initializer_list<value_type> __il);
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT
+        {return allocator_type(__table_.__node_alloc());}
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool      empty() const _NOEXCEPT {return __table_.size() == 0;}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT  {return __table_.size();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT {return __table_.max_size();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       begin() _NOEXCEPT        {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       end() _NOEXCEPT          {return __table_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin()  const _NOEXCEPT {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()    const _NOEXCEPT {return __table_.end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin() const _NOEXCEPT {return __table_.begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend()   const _NOEXCEPT {return __table_.end();}
+
+#ifndef _LIBCPP_CXX03_LANG
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator emplace(_Args&&... __args)
+            {return __table_.__emplace_multi(_VSTD::forward<_Args>(__args)...);}
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+        iterator emplace_hint(const_iterator __p, _Args&&... __args)
+            {return __table_.__emplace_hint_multi(__p, _VSTD::forward<_Args>(__args)...);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(value_type&& __x) {return __table_.__insert_multi(_VSTD::move(__x));}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, value_type&& __x)
+        {return __table_.__insert_multi(__p, _VSTD::move(__x));}
+    _LIBCPP_INLINE_VISIBILITY
+    void insert(initializer_list<value_type> __il)
+        {insert(__il.begin(), __il.end());}
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const value_type& __x) {return __table_.__insert_multi(__x);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __p, const value_type& __x)
+        {return __table_.__insert_multi(__p, __x);}
+
+    template <class _InputIterator>
+        _LIBCPP_INLINE_VISIBILITY
+        void insert(_InputIterator __first, _InputIterator __last);
+
+#if _LIBCPP_STD_VER > 14
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to unordered_multiset::insert()");
+        return __table_.template __node_handle_insert_multi<node_type>(
+            _VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __hint, node_type&& __nh)
+    {
+        _LIBCPP_ASSERT(__nh.empty() || __nh.get_allocator() == get_allocator(),
+            "node_type with incompatible allocator passed to unordered_multiset::insert()");
+        return __table_.template __node_handle_insert_multi<node_type>(
+            __hint, _VSTD::move(__nh));
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(const_iterator __position)
+    {
+        return __table_.template __node_handle_extract<node_type>(
+            __position);
+    }
+    _LIBCPP_INLINE_VISIBILITY
+    node_type extract(key_type const& __key)
+    {
+        return __table_.template __node_handle_extract<node_type>(__key);
+    }
+
+    template <class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_multiset<key_type, _H2, _P2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __table_.__node_handle_merge_multi(__source.__table_);
+    }
+    template <class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_multiset<key_type, _H2, _P2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __table_.__node_handle_merge_multi(__source.__table_);
+    }
+    template <class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_set<key_type, _H2, _P2, allocator_type>& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __table_.__node_handle_merge_multi(__source.__table_);
+    }
+    template <class _H2, class _P2>
+    _LIBCPP_INLINE_VISIBILITY
+    void merge(unordered_set<key_type, _H2, _P2, allocator_type>&& __source)
+    {
+        _LIBCPP_ASSERT(__source.get_allocator() == get_allocator(),
+                       "merging container with incompatible allocator");
+        return __table_.__node_handle_merge_multi(__source.__table_);
+    }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(const_iterator __p) {return __table_.erase(__p);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type erase(const key_type& __k) {return __table_.__erase_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator erase(const_iterator __first, const_iterator __last)
+        {return __table_.erase(__first, __last);}
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT {__table_.clear();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(unordered_multiset& __u)
+        _NOEXCEPT_(__is_nothrow_swappable<__table>::value)
+        {__table_.swap(__u.__table_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    hasher hash_function() const {return __table_.hash_function();}
+    _LIBCPP_INLINE_VISIBILITY
+    key_equal key_eq() const {return __table_.key_eq();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       find(const key_type& __k)       {return __table_.find(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const key_type& __k) const {return __table_.find(__k);}
+#if _LIBCPP_STD_VER > 17
+    template<class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       find(const _K2& __k)            {return __table_.find(__k);}
+    template<class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator find(const _K2& __k) const      {return __table_.find(__k);}
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type count(const key_type& __k) const {return __table_.__count_multi(__k);}
+#if _LIBCPP_STD_VER > 17
+    template<class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    size_type count(const _K2& __k) const      {return __table_.__count_multi(__k);}
+#endif // _LIBCPP_STD_VER > 17
+
+#if _LIBCPP_STD_VER > 17
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const key_type& __k) const {return find(__k) != end();}
+
+    template<class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    bool contains(const _K2& __k) const      {return find(__k) != end();}
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, iterator>             equal_range(const key_type& __k)
+        {return __table_.__equal_range_multi(__k);}
+    _LIBCPP_INLINE_VISIBILITY
+    pair<const_iterator, const_iterator> equal_range(const key_type& __k) const
+        {return __table_.__equal_range_multi(__k);}
+#if _LIBCPP_STD_VER > 17
+    template<class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<iterator, iterator>             equal_range(const _K2& __k)
+        {return __table_.__equal_range_multi(__k);}
+    template<class _K2, enable_if_t<__is_transparent<hasher, _K2>::value && __is_transparent<key_equal, _K2>::value>* = nullptr>
+    _LIBCPP_INLINE_VISIBILITY
+    pair<const_iterator, const_iterator> equal_range(const _K2& __k) const
+        {return __table_.__equal_range_multi(__k);}
+#endif // _LIBCPP_STD_VER > 17
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket_count() const _NOEXCEPT {return __table_.bucket_count();}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type max_bucket_count() const _NOEXCEPT {return __table_.max_bucket_count();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket_size(size_type __n) const {return __table_.bucket_size(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type bucket(const key_type& __k) const {return __table_.bucket(__k);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    local_iterator       begin(size_type __n)        {return __table_.begin(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    local_iterator       end(size_type __n)          {return __table_.end(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator begin(size_type __n) const  {return __table_.cbegin(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator end(size_type __n) const    {return __table_.cend(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator cbegin(size_type __n) const {return __table_.cbegin(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_local_iterator cend(size_type __n) const   {return __table_.cend(__n);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    float load_factor() const _NOEXCEPT {return __table_.load_factor();}
+    _LIBCPP_INLINE_VISIBILITY
+    float max_load_factor() const _NOEXCEPT {return __table_.max_load_factor();}
+    _LIBCPP_INLINE_VISIBILITY
+    void max_load_factor(float __mlf) {__table_.max_load_factor(__mlf);}
+    _LIBCPP_INLINE_VISIBILITY
+    void rehash(size_type __n) {__table_.rehash(__n);}
+    _LIBCPP_INLINE_VISIBILITY
+    void reserve(size_type __n) {__table_.reserve(__n);}
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+    bool __dereferenceable(const const_iterator* __i) const
+        {return __table_.__dereferenceable(__i);}
+    bool __decrementable(const const_iterator* __i) const
+        {return __table_.__decrementable(__i);}
+    bool __addable(const const_iterator* __i, ptrdiff_t __n) const
+        {return __table_.__addable(__i, __n);}
+    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const
+        {return __table_.__addable(__i, __n);}
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator,
+         class _Hash = hash<__iter_value_type<_InputIterator>>,
+         class _Pred = equal_to<__iter_value_type<_InputIterator>>,
+         class _Allocator = allocator<__iter_value_type<_InputIterator>>,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<!__is_allocator<_Pred>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multiset(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type = 0,
+              _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
+  -> unordered_multiset<__iter_value_type<_InputIterator>, _Hash, _Pred, _Allocator>;
+
+template<class _Tp, class _Hash = hash<_Tp>,
+         class _Pred = equal_to<_Tp>, class _Allocator = allocator<_Tp>,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<!__is_allocator<_Pred>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multiset(initializer_list<_Tp>, typename allocator_traits<_Allocator>::size_type = 0,
+              _Hash = _Hash(), _Pred = _Pred(), _Allocator = _Allocator())
+  -> unordered_multiset<_Tp, _Hash, _Pred, _Allocator>;
+
+template<class _InputIterator, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multiset(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type, _Allocator)
+  -> unordered_multiset<__iter_value_type<_InputIterator>,
+                   hash<__iter_value_type<_InputIterator>>,
+                   equal_to<__iter_value_type<_InputIterator>>,
+                   _Allocator>;
+
+template<class _InputIterator, class _Hash, class _Allocator,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multiset(_InputIterator, _InputIterator, typename allocator_traits<_Allocator>::size_type,
+              _Hash, _Allocator)
+  -> unordered_multiset<__iter_value_type<_InputIterator>, _Hash,
+                   equal_to<__iter_value_type<_InputIterator>>,
+                   _Allocator>;
+
+template<class _Tp, class _Allocator,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multiset(initializer_list<_Tp>, typename allocator_traits<_Allocator>::size_type, _Allocator)
+  -> unordered_multiset<_Tp, hash<_Tp>, equal_to<_Tp>, _Allocator>;
+
+template<class _Tp, class _Hash, class _Allocator,
+         class = enable_if_t<!__is_allocator<_Hash>::value>,
+         class = enable_if_t<!is_integral<_Hash>::value>,
+         class = enable_if_t<__is_allocator<_Allocator>::value>>
+unordered_multiset(initializer_list<_Tp>, typename allocator_traits<_Allocator>::size_type, _Hash, _Allocator)
+  -> unordered_multiset<_Tp, _Hash, equal_to<_Tp>, _Allocator>;
+#endif
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
+        size_type __n, const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
+        size_type __n, const hasher& __hf, const key_equal& __eql,
+        const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
+        _InputIterator __first, _InputIterator __last)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    insert(__first, __last);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
+        _InputIterator __first, _InputIterator __last, size_type __n,
+        const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__first, __last);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
+        const allocator_type& __a)
+    : __table_(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
+        const unordered_multiset& __u)
+    : __table_(__u.__table_)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__u.bucket_count());
+    insert(__u.begin(), __u.end());
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
+        const unordered_multiset& __u, const allocator_type& __a)
+    : __table_(__u.__table_, __a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__u.bucket_count());
+    insert(__u.begin(), __u.end());
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
+        unordered_multiset&& __u)
+    _NOEXCEPT_(is_nothrow_move_constructible<__table>::value)
+    : __table_(_VSTD::move(__u.__table_))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+    __get_db()->swap(this, &__u);
+#endif
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
+        unordered_multiset&& __u, const allocator_type& __a)
+    : __table_(_VSTD::move(__u.__table_), __a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    if (__a != __u.get_allocator())
+    {
+        iterator __i = __u.begin();
+        while (__u.size() != 0)
+            __table_.__insert_multi(_VSTD::move(__u.__table_.remove(__i++)->__value_));
+    }
+#if _LIBCPP_DEBUG_LEVEL == 2
+    else
+        __get_db()->swap(this, &__u);
+#endif
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
+        initializer_list<value_type> __il)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    insert(__il.begin(), __il.end());
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
+        initializer_list<value_type> __il, size_type __n, const hasher& __hf,
+        const key_equal& __eql)
+    : __table_(__hf, __eql)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__il.begin(), __il.end());
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::unordered_multiset(
+        initializer_list<value_type> __il, size_type __n, const hasher& __hf,
+        const key_equal& __eql, const allocator_type& __a)
+    : __table_(__hf, __eql, __a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    __table_.rehash(__n);
+    insert(__il.begin(), __il.end());
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>&
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::operator=(
+        unordered_multiset&& __u)
+    _NOEXCEPT_(is_nothrow_move_assignable<__table>::value)
+{
+    __table_ = _VSTD::move(__u.__table_);
+    return *this;
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>&
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::operator=(
+        initializer_list<value_type> __il)
+{
+    __table_.__assign_multi(__il.begin(), __il.end());
+    return *this;
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+template <class _InputIterator>
+inline
+void
+unordered_multiset<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator __first,
+                                                         _InputIterator __last)
+{
+    for (; __first != __last; ++__first)
+        __table_.__insert_multi(*__first);
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
+     unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Value, class _Hash, class _Pred, class _Alloc,
+          class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY
+    typename unordered_multiset<_Value, _Hash, _Pred, _Alloc>::size_type
+    erase_if(unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __c,
+             _Predicate __pred) {
+  return _VSTD::__libcpp_erase_if_container(__c, __pred);
+}
+#endif
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+bool
+operator==(const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
+           const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __y)
+{
+    if (__x.size() != __y.size())
+        return false;
+    typedef typename unordered_multiset<_Value, _Hash, _Pred, _Alloc>::const_iterator
+                                                                 const_iterator;
+    typedef pair<const_iterator, const_iterator> _EqRng;
+    for (const_iterator __i = __x.begin(), __ex = __x.end(); __i != __ex;)
+    {
+        _EqRng __xeq = __x.equal_range(*__i);
+        _EqRng __yeq = __y.equal_range(*__i);
+        if (_VSTD::distance(__xeq.first, __xeq.second) !=
+            _VSTD::distance(__yeq.first, __yeq.second) ||
+                  !_VSTD::is_permutation(__xeq.first, __xeq.second, __yeq.first))
+            return false;
+        __i = __xeq.second;
+    }
+    return true;
+}
+
+template <class _Value, class _Hash, class _Pred, class _Alloc>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __x,
+           const unordered_multiset<_Value, _Hash, _Pred, _Alloc>& __y)
+{
+    return !(__x == __y);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_UNORDERED_SET
diff --git a/contrib/libs/cxxsupp/libcxx/include/unwind.h b/contrib/libs/cxxsupp/libcxx/include/unwind.h
new file mode 100644
index 00000000000..c6082022306
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/unwind.h
@@ -0,0 +1,7 @@
+#pragma once
+
+#if defined(__IOS__)
+#include_next <unwind.h>
+#else
+#include <contrib/libs/cxxsupp/libcxxrt/unwind.h>
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/include/use_ansi.h b/contrib/libs/cxxsupp/libcxx/include/use_ansi.h
new file mode 100644
index 00000000000..2b6f36d4eff
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/use_ansi.h
@@ -0,0 +1,3 @@
+// Empty header to prevent MSVC one from inclusion.
+// This MSVC header adds Microsoft STL to the linker arguments
+// which causes conflicts with libc++.
\ No newline at end of file
diff --git a/contrib/libs/cxxsupp/libcxx/include/utility b/contrib/libs/cxxsupp/libcxx/include/utility
new file mode 100644
index 00000000000..7d021d95802
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/utility
@@ -0,0 +1,235 @@
+// -*- C++ -*-
+//===-------------------------- utility -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_UTILITY
+#define _LIBCPP_UTILITY
+
+/*
+    utility synopsis
+
+#include <initializer_list>
+
+namespace std
+{
+
+template <class T>
+    void
+    swap(T& a, T& b);
+
+namespace rel_ops
+{
+    template<class T> bool operator!=(const T&, const T&);
+    template<class T> bool operator> (const T&, const T&);
+    template<class T> bool operator<=(const T&, const T&);
+    template<class T> bool operator>=(const T&, const T&);
+}
+
+template<class T>
+void
+swap(T& a, T& b) noexcept(is_nothrow_move_constructible<T>::value &&
+                          is_nothrow_move_assignable<T>::value);
+
+template <class T, size_t N>
+void
+swap(T (&a)[N], T (&b)[N]) noexcept(noexcept(swap(*a, *b)));
+
+template <class T> T&& forward(typename remove_reference<T>::type& t) noexcept;  // constexpr in C++14
+template <class T> T&& forward(typename remove_reference<T>::type&& t) noexcept; // constexpr in C++14
+
+template <class T> typename remove_reference<T>::type&& move(T&&) noexcept;      // constexpr in C++14
+
+template <class T>
+    typename conditional
+    <
+        !is_nothrow_move_constructible<T>::value && is_copy_constructible<T>::value,
+        const T&,
+        T&&
+    >::type
+    move_if_noexcept(T& x) noexcept; // constexpr in C++14
+
+template <class T> constexpr add_const_t<T>& as_const(T& t) noexcept;      // C++17
+template <class T>                      void as_const(const T&&) = delete; // C++17
+
+template <class T> typename add_rvalue_reference<T>::type declval() noexcept;
+
+template<class T, class U> constexpr bool cmp_equal(T t, U u) noexcept;         // C++20
+template<class T, class U> constexpr bool cmp_not_equal(T t, U u) noexcept;     // C++20
+template<class T, class U> constexpr bool cmp_less(T t, U u) noexcept;          // C++20
+template<class T, class U> constexpr bool cmp_greater(T t, U u) noexcept;       // C++20
+template<class T, class U> constexpr bool cmp_less_equal(T t, U u) noexcept;    // C++20
+template<class T, class U> constexpr bool cmp_greater_equal(T t, U u) noexcept; // C++20
+template<class R, class T> constexpr bool in_range(T t) noexcept;               // C++20
+
+template <class T1, class T2>
+struct pair
+{
+    typedef T1 first_type;
+    typedef T2 second_type;
+
+    T1 first;
+    T2 second;
+
+    pair(const pair&) = default;
+    pair(pair&&) = default;
+    explicit(see-below) constexpr pair();
+    explicit(see-below) pair(const T1& x, const T2& y);                          // constexpr in C++14
+    template <class U = T1, class V = T2> explicit(see-below) pair(U&&, V&&);    // constexpr in C++14
+    template <class U, class V> explicit(see-below) pair(const pair<U, V>& p);   // constexpr in C++14
+    template <class U, class V> explicit(see-below) pair(pair<U, V>&& p);        // constexpr in C++14
+    template <class... Args1, class... Args2>
+        pair(piecewise_construct_t, tuple<Args1...> first_args,
+             tuple<Args2...> second_args);                                       // constexpr in C++20
+
+    template <class U, class V> pair& operator=(const pair<U, V>& p);            // constexpr in C++20
+    pair& operator=(pair&& p) noexcept(is_nothrow_move_assignable<T1>::value &&
+                                       is_nothrow_move_assignable<T2>::value);   // constexpr in C++20
+    template <class U, class V> pair& operator=(pair<U, V>&& p);                 // constexpr in C++20
+
+    void swap(pair& p) noexcept(is_nothrow_swappable_v<T1> &&
+                                is_nothrow_swappable_v<T2>);                     // constexpr in C++20
+};
+
+template <class T1, class T2> bool operator==(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
+template <class T1, class T2> bool operator!=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14, removed in C++20
+template <class T1, class T2> bool operator< (const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14, removed in C++20
+template <class T1, class T2> bool operator> (const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14, removed in C++20
+template <class T1, class T2> bool operator>=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14, removed in C++20
+template <class T1, class T2> bool operator<=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14, removed in C++20
+template <class T1, class T2>
+  constexpr common_comparison_type_t<synth-three-way-result<T1>,
+                                     synth-three-way-result<T2>>
+    operator<=>(const pair<T1,T2>&, const pair<T1,T2>&);                               // C++20
+
+template <class T1, class T2> pair<V1, V2> make_pair(T1&&, T2&&);                // constexpr in C++14
+template <class T1, class T2>
+void
+swap(pair<T1, T2>& x, pair<T1, T2>& y) noexcept(noexcept(x.swap(y)));            // constexpr in C++20
+
+struct piecewise_construct_t { explicit piecewise_construct_t() = default; };
+inline constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
+
+template <class T> struct tuple_size;
+template <size_t I, class T> struct tuple_element;
+
+template <class T1, class T2> struct tuple_size<pair<T1, T2> >;
+template <class T1, class T2> struct tuple_element<0, pair<T1, T2> >;
+template <class T1, class T2> struct tuple_element<1, pair<T1, T2> >;
+
+template<size_t I, class T1, class T2>
+    typename tuple_element<I, pair<T1, T2> >::type&
+    get(pair<T1, T2>&) noexcept; // constexpr in C++14
+
+template<size_t I, class T1, class T2>
+    const typename tuple_element<I, pair<T1, T2> >::type&
+    get(const pair<T1, T2>&) noexcept; // constexpr in C++14
+
+template<size_t I, class T1, class T2>
+    typename tuple_element<I, pair<T1, T2> >::type&&
+    get(pair<T1, T2>&&) noexcept; // constexpr in C++14
+
+template<size_t I, class T1, class T2>
+    const typename tuple_element<I, pair<T1, T2> >::type&&
+    get(const pair<T1, T2>&&) noexcept; // constexpr in C++14
+
+template<class T1, class T2>
+    constexpr T1& get(pair<T1, T2>&) noexcept; // C++14
+
+template<class T1, class T2>
+    constexpr const T1& get(const pair<T1, T2>&) noexcept; // C++14
+
+template<class T1, class T2>
+    constexpr T1&& get(pair<T1, T2>&&) noexcept; // C++14
+
+template<class T1, class T2>
+    constexpr const T1&& get(const pair<T1, T2>&&) noexcept; // C++14
+
+template<class T1, class T2>
+    constexpr T1& get(pair<T2, T1>&) noexcept; // C++14
+
+template<class T1, class T2>
+    constexpr const T1& get(const pair<T2, T1>&) noexcept; // C++14
+
+template<class T1, class T2>
+    constexpr T1&& get(pair<T2, T1>&&) noexcept; // C++14
+
+template<class T1, class T2>
+    constexpr const T1&& get(const pair<T2, T1>&&) noexcept; // C++14
+
+// C++14
+
+template<class T, T... I>
+struct integer_sequence
+{
+    typedef T value_type;
+
+    static constexpr size_t size() noexcept;
+};
+
+template<size_t... I>
+  using index_sequence = integer_sequence<size_t, I...>;
+
+template<class T, T N>
+  using make_integer_sequence = integer_sequence<T, 0, 1, ..., N-1>;
+template<size_t N>
+  using make_index_sequence = make_integer_sequence<size_t, N>;
+
+template<class... T>
+  using index_sequence_for = make_index_sequence<sizeof...(T)>;
+
+template<class T, class U=T>
+    constexpr T exchange(T& obj, U&& new_value)
+      noexcept(is_nothrow_move_constructible<T>::value && is_nothrow_assignable<T&, U>::value); // constexpr in C++17, noexcept in C++23
+
+// 20.2.7, in-place construction // C++17
+struct in_place_t {
+  explicit in_place_t() = default;
+};
+inline constexpr in_place_t in_place{};
+template <class T>
+  struct in_place_type_t {
+    explicit in_place_type_t() = default;
+  };
+template <class T>
+  inline constexpr in_place_type_t<T> in_place_type{};
+template <size_t I>
+  struct in_place_index_t {
+    explicit in_place_index_t() = default;
+  };
+template <size_t I>
+  inline constexpr in_place_index_t<I> in_place_index{};
+
+// [utility.underlying], to_underlying
+template <class T>
+    constexpr underlying_type_t<T> to_underlying( T value ) noexcept; // C++2b
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__debug>
+#include <__tuple>
+#include <__utility/as_const.h>
+#include <__utility/cmp.h>
+#include <__utility/declval.h>
+#include <__utility/exchange.h>
+#include <__utility/forward.h>
+#include <__utility/in_place.h>
+#include <__utility/integer_sequence.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+#include <__utility/piecewise_construct.h>
+#include <__utility/rel_ops.h>
+#include <__utility/swap.h>
+#include <__utility/to_underlying.h>
+#include <compare>
+#include <initializer_list>
+#include <version>
+
+#endif // _LIBCPP_UTILITY
diff --git a/contrib/libs/cxxsupp/libcxx/include/valarray b/contrib/libs/cxxsupp/libcxx/include/valarray
new file mode 100644
index 00000000000..0a828885d29
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/valarray
@@ -0,0 +1,4929 @@
+// -*- C++ -*-
+//===-------------------------- valarray ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_VALARRAY
+#define _LIBCPP_VALARRAY
+
+/*
+    valarray synopsis
+
+namespace std
+{
+
+template<class T>
+class valarray
+{
+public:
+    typedef T value_type;
+
+    // construct/destroy:
+    valarray();
+    explicit valarray(size_t n);
+    valarray(const value_type& x, size_t n);
+    valarray(const value_type* px, size_t n);
+    valarray(const valarray& v);
+    valarray(valarray&& v) noexcept;
+    valarray(const slice_array<value_type>& sa);
+    valarray(const gslice_array<value_type>& ga);
+    valarray(const mask_array<value_type>& ma);
+    valarray(const indirect_array<value_type>& ia);
+    valarray(initializer_list<value_type> il);
+    ~valarray();
+
+    // assignment:
+    valarray& operator=(const valarray& v);
+    valarray& operator=(valarray&& v) noexcept;
+    valarray& operator=(initializer_list<value_type> il);
+    valarray& operator=(const value_type& x);
+    valarray& operator=(const slice_array<value_type>& sa);
+    valarray& operator=(const gslice_array<value_type>& ga);
+    valarray& operator=(const mask_array<value_type>& ma);
+    valarray& operator=(const indirect_array<value_type>& ia);
+
+    // element access:
+    const value_type& operator[](size_t i) const;
+    value_type&       operator[](size_t i);
+
+    // subset operations:
+    valarray                   operator[](slice s) const;
+    slice_array<value_type>    operator[](slice s);
+    valarray                   operator[](const gslice& gs) const;
+    gslice_array<value_type>   operator[](const gslice& gs);
+    valarray                   operator[](const valarray<bool>& vb) const;
+    mask_array<value_type>     operator[](const valarray<bool>& vb);
+    valarray                   operator[](const valarray<size_t>& vs) const;
+    indirect_array<value_type> operator[](const valarray<size_t>& vs);
+
+    // unary operators:
+    valarray       operator+() const;
+    valarray       operator-() const;
+    valarray       operator~() const;
+    valarray<bool> operator!() const;
+
+    // computed assignment:
+    valarray& operator*= (const value_type& x);
+    valarray& operator/= (const value_type& x);
+    valarray& operator%= (const value_type& x);
+    valarray& operator+= (const value_type& x);
+    valarray& operator-= (const value_type& x);
+    valarray& operator^= (const value_type& x);
+    valarray& operator&= (const value_type& x);
+    valarray& operator|= (const value_type& x);
+    valarray& operator<<=(const value_type& x);
+    valarray& operator>>=(const value_type& x);
+
+    valarray& operator*= (const valarray& v);
+    valarray& operator/= (const valarray& v);
+    valarray& operator%= (const valarray& v);
+    valarray& operator+= (const valarray& v);
+    valarray& operator-= (const valarray& v);
+    valarray& operator^= (const valarray& v);
+    valarray& operator|= (const valarray& v);
+    valarray& operator&= (const valarray& v);
+    valarray& operator<<=(const valarray& v);
+    valarray& operator>>=(const valarray& v);
+
+    // member functions:
+    void swap(valarray& v) noexcept;
+
+    size_t size() const;
+
+    value_type sum() const;
+    value_type min() const;
+    value_type max() const;
+
+    valarray shift (int i) const;
+    valarray cshift(int i) const;
+    valarray apply(value_type f(value_type)) const;
+    valarray apply(value_type f(const value_type&)) const;
+    void resize(size_t n, value_type x = value_type());
+};
+
+class slice
+{
+public:
+    slice();
+    slice(size_t start, size_t size, size_t stride);
+
+    size_t start()  const;
+    size_t size()   const;
+    size_t stride() const;
+};
+
+template <class T>
+class slice_array
+{
+public:
+    typedef T value_type;
+
+    const slice_array& operator=(const slice_array& sa) const;
+    void operator=  (const valarray<value_type>& v) const;
+    void operator*= (const valarray<value_type>& v) const;
+    void operator/= (const valarray<value_type>& v) const;
+    void operator%= (const valarray<value_type>& v) const;
+    void operator+= (const valarray<value_type>& v) const;
+    void operator-= (const valarray<value_type>& v) const;
+    void operator^= (const valarray<value_type>& v) const;
+    void operator&= (const valarray<value_type>& v) const;
+    void operator|= (const valarray<value_type>& v) const;
+    void operator<<=(const valarray<value_type>& v) const;
+    void operator>>=(const valarray<value_type>& v) const;
+
+    void operator=(const value_type& x) const;
+    void operator=(const valarray<T>& val_arr) const;
+
+    slice_array() = delete;
+};
+
+class gslice
+{
+public:
+    gslice();
+    gslice(size_t start, const valarray<size_t>& size,
+                         const valarray<size_t>& stride);
+
+    size_t           start()  const;
+    valarray<size_t> size()   const;
+    valarray<size_t> stride() const;
+};
+
+template <class T>
+class gslice_array
+{
+public:
+    typedef T value_type;
+
+    void operator=  (const valarray<value_type>& v) const;
+    void operator*= (const valarray<value_type>& v) const;
+    void operator/= (const valarray<value_type>& v) const;
+    void operator%= (const valarray<value_type>& v) const;
+    void operator+= (const valarray<value_type>& v) const;
+    void operator-= (const valarray<value_type>& v) const;
+    void operator^= (const valarray<value_type>& v) const;
+    void operator&= (const valarray<value_type>& v) const;
+    void operator|= (const valarray<value_type>& v) const;
+    void operator<<=(const valarray<value_type>& v) const;
+    void operator>>=(const valarray<value_type>& v) const;
+
+    gslice_array(const gslice_array& ga);
+    ~gslice_array();
+    const gslice_array& operator=(const gslice_array& ga) const;
+    void operator=(const value_type& x) const;
+
+    gslice_array() = delete;
+};
+
+template <class T>
+class mask_array
+{
+public:
+    typedef T value_type;
+
+    void operator=  (const valarray<value_type>& v) const;
+    void operator*= (const valarray<value_type>& v) const;
+    void operator/= (const valarray<value_type>& v) const;
+    void operator%= (const valarray<value_type>& v) const;
+    void operator+= (const valarray<value_type>& v) const;
+    void operator-= (const valarray<value_type>& v) const;
+    void operator^= (const valarray<value_type>& v) const;
+    void operator&= (const valarray<value_type>& v) const;
+    void operator|= (const valarray<value_type>& v) const;
+    void operator<<=(const valarray<value_type>& v) const;
+    void operator>>=(const valarray<value_type>& v) const;
+
+    mask_array(const mask_array& ma);
+    ~mask_array();
+    const mask_array& operator=(const mask_array& ma) const;
+    void operator=(const value_type& x) const;
+
+    mask_array() = delete;
+};
+
+template <class T>
+class indirect_array
+{
+public:
+    typedef T value_type;
+
+    void operator=  (const valarray<value_type>& v) const;
+    void operator*= (const valarray<value_type>& v) const;
+    void operator/= (const valarray<value_type>& v) const;
+    void operator%= (const valarray<value_type>& v) const;
+    void operator+= (const valarray<value_type>& v) const;
+    void operator-= (const valarray<value_type>& v) const;
+    void operator^= (const valarray<value_type>& v) const;
+    void operator&= (const valarray<value_type>& v) const;
+    void operator|= (const valarray<value_type>& v) const;
+    void operator<<=(const valarray<value_type>& v) const;
+    void operator>>=(const valarray<value_type>& v) const;
+
+    indirect_array(const indirect_array& ia);
+    ~indirect_array();
+    const indirect_array& operator=(const indirect_array& ia) const;
+    void operator=(const value_type& x) const;
+
+    indirect_array() = delete;
+};
+
+template<class T> void swap(valarray<T>& x, valarray<T>& y) noexcept;
+
+template<class T> valarray<T> operator* (const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<T> operator* (const valarray<T>& x, const T& y);
+template<class T> valarray<T> operator* (const T& x, const valarray<T>& y);
+
+template<class T> valarray<T> operator/ (const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<T> operator/ (const valarray<T>& x, const T& y);
+template<class T> valarray<T> operator/ (const T& x, const valarray<T>& y);
+
+template<class T> valarray<T> operator% (const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<T> operator% (const valarray<T>& x, const T& y);
+template<class T> valarray<T> operator% (const T& x, const valarray<T>& y);
+
+template<class T> valarray<T> operator+ (const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<T> operator+ (const valarray<T>& x, const T& y);
+template<class T> valarray<T> operator+ (const T& x, const valarray<T>& y);
+
+template<class T> valarray<T> operator- (const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<T> operator- (const valarray<T>& x, const T& y);
+template<class T> valarray<T> operator- (const T& x, const valarray<T>& y);
+
+template<class T> valarray<T> operator^ (const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<T> operator^ (const valarray<T>& x, const T& y);
+template<class T> valarray<T> operator^ (const T& x, const valarray<T>& y);
+
+template<class T> valarray<T> operator& (const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<T> operator& (const valarray<T>& x, const T& y);
+template<class T> valarray<T> operator& (const T& x, const valarray<T>& y);
+
+template<class T> valarray<T> operator| (const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<T> operator| (const valarray<T>& x, const T& y);
+template<class T> valarray<T> operator| (const T& x, const valarray<T>& y);
+
+template<class T> valarray<T> operator<<(const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<T> operator<<(const valarray<T>& x, const T& y);
+template<class T> valarray<T> operator<<(const T& x, const valarray<T>& y);
+
+template<class T> valarray<T> operator>>(const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<T> operator>>(const valarray<T>& x, const T& y);
+template<class T> valarray<T> operator>>(const T& x, const valarray<T>& y);
+
+template<class T> valarray<bool> operator&&(const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<bool> operator&&(const valarray<T>& x, const T& y);
+template<class T> valarray<bool> operator&&(const T& x, const valarray<T>& y);
+
+template<class T> valarray<bool> operator||(const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<bool> operator||(const valarray<T>& x, const T& y);
+template<class T> valarray<bool> operator||(const T& x, const valarray<T>& y);
+
+template<class T> valarray<bool> operator==(const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<bool> operator==(const valarray<T>& x, const T& y);
+template<class T> valarray<bool> operator==(const T& x, const valarray<T>& y);
+
+template<class T> valarray<bool> operator!=(const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<bool> operator!=(const valarray<T>& x, const T& y);
+template<class T> valarray<bool> operator!=(const T& x, const valarray<T>& y);
+
+template<class T> valarray<bool> operator< (const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<bool> operator< (const valarray<T>& x, const T& y);
+template<class T> valarray<bool> operator< (const T& x, const valarray<T>& y);
+
+template<class T> valarray<bool> operator> (const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<bool> operator> (const valarray<T>& x, const T& y);
+template<class T> valarray<bool> operator> (const T& x, const valarray<T>& y);
+
+template<class T> valarray<bool> operator<=(const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<bool> operator<=(const valarray<T>& x, const T& y);
+template<class T> valarray<bool> operator<=(const T& x, const valarray<T>& y);
+
+template<class T> valarray<bool> operator>=(const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<bool> operator>=(const valarray<T>& x, const T& y);
+template<class T> valarray<bool> operator>=(const T& x, const valarray<T>& y);
+
+template<class T> valarray<T> abs (const valarray<T>& x);
+template<class T> valarray<T> acos (const valarray<T>& x);
+template<class T> valarray<T> asin (const valarray<T>& x);
+template<class T> valarray<T> atan (const valarray<T>& x);
+
+template<class T> valarray<T> atan2(const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<T> atan2(const valarray<T>& x, const T& y);
+template<class T> valarray<T> atan2(const T& x, const valarray<T>& y);
+
+template<class T> valarray<T> cos (const valarray<T>& x);
+template<class T> valarray<T> cosh (const valarray<T>& x);
+template<class T> valarray<T> exp (const valarray<T>& x);
+template<class T> valarray<T> log (const valarray<T>& x);
+template<class T> valarray<T> log10(const valarray<T>& x);
+
+template<class T> valarray<T> pow(const valarray<T>& x, const valarray<T>& y);
+template<class T> valarray<T> pow(const valarray<T>& x, const T& y);
+template<class T> valarray<T> pow(const T& x, const valarray<T>& y);
+
+template<class T> valarray<T> sin (const valarray<T>& x);
+template<class T> valarray<T> sinh (const valarray<T>& x);
+template<class T> valarray<T> sqrt (const valarray<T>& x);
+template<class T> valarray<T> tan (const valarray<T>& x);
+template<class T> valarray<T> tanh (const valarray<T>& x);
+
+template <class T> unspecified1 begin(valarray<T>& v);
+template <class T> unspecified2 begin(const valarray<T>& v);
+template <class T> unspecified1 end(valarray<T>& v);
+template <class T> unspecified2 end(const valarray<T>& v);
+
+}  // std
+
+*/
+
+#include <__config>
+#include <algorithm>
+#include <cmath>
+#include <cstddef>
+#include <functional>
+#include <initializer_list>
+#include <new>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _Tp> class _LIBCPP_TEMPLATE_VIS valarray;
+
+class _LIBCPP_TEMPLATE_VIS slice
+{
+    size_t __start_;
+    size_t __size_;
+    size_t __stride_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    slice()
+        : __start_(0),
+          __size_(0),
+          __stride_(0)
+          {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    slice(size_t __start, size_t __size, size_t __stride)
+        : __start_(__start),
+          __size_(__size),
+          __stride_(__stride)
+          {}
+
+    _LIBCPP_INLINE_VISIBILITY size_t start()  const {return __start_;}
+    _LIBCPP_INLINE_VISIBILITY size_t size()   const {return __size_;}
+    _LIBCPP_INLINE_VISIBILITY size_t stride() const {return __stride_;}
+};
+
+template <class _Tp> class _LIBCPP_TEMPLATE_VIS slice_array;
+class _LIBCPP_TYPE_VIS gslice;
+template <class _Tp> class _LIBCPP_TEMPLATE_VIS gslice_array;
+template <class _Tp> class _LIBCPP_TEMPLATE_VIS mask_array;
+template <class _Tp> class _LIBCPP_TEMPLATE_VIS indirect_array;
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp*
+begin(valarray<_Tp>& __v);
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+const _Tp*
+begin(const valarray<_Tp>& __v);
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+_Tp*
+end(valarray<_Tp>& __v);
+
+template <class _Tp>
+_LIBCPP_INLINE_VISIBILITY
+const _Tp*
+end(const valarray<_Tp>& __v);
+
+template <class _Op, class _A0>
+struct _UnaryOp
+{
+    typedef typename _Op::__result_type __result_type;
+    typedef typename decay<__result_type>::type value_type;
+
+    _Op __op_;
+    _A0 __a0_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _UnaryOp(const _Op& __op, const _A0& __a0) : __op_(__op), __a0_(__a0) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type operator[](size_t __i) const {return __op_(__a0_[__i]);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return __a0_.size();}
+};
+
+template <class _Op, class _A0, class _A1>
+struct _BinaryOp
+{
+    typedef typename _Op::__result_type __result_type;
+    typedef typename decay<__result_type>::type value_type;
+
+    _Op __op_;
+    _A0 __a0_;
+    _A1 __a1_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _BinaryOp(const _Op& __op, const _A0& __a0, const _A1& __a1)
+        : __op_(__op), __a0_(__a0), __a1_(__a1) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type operator[](size_t __i) const {return __op_(__a0_[__i], __a1_[__i]);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return __a0_.size();}
+};
+
+template <class _Tp>
+class __scalar_expr
+{
+public:
+    typedef _Tp        value_type;
+    typedef const _Tp& __result_type;
+private:
+    const value_type& __t_;
+    size_t __s_;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __scalar_expr(const value_type& __t, size_t __s) : __t_(__t), __s_(__s) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type operator[](size_t) const {return __t_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return __s_;}
+};
+
+template <class _Tp>
+struct __unary_plus
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return +__x;}
+};
+
+template <class _Tp>
+struct __bit_not
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return ~__x;}
+};
+
+template <class _Tp>
+struct __bit_shift_left
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x << __y;}
+};
+
+template <class _Tp>
+struct __bit_shift_right
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x, const _Tp& __y) const
+        {return __x >> __y;}
+};
+
+template <class _Tp, class _Fp>
+struct __apply_expr
+{
+private:
+    _Fp __f_;
+public:
+    typedef _Tp __result_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __apply_expr(_Fp __f) : __f_(__f) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return __f_(__x);}
+};
+
+template <class _Tp>
+struct __abs_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return abs(__x);}
+};
+
+template <class _Tp>
+struct __acos_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return acos(__x);}
+};
+
+template <class _Tp>
+struct __asin_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return asin(__x);}
+};
+
+template <class _Tp>
+struct __atan_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return atan(__x);}
+};
+
+template <class _Tp>
+struct __atan2_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x, const _Tp& __y) const
+        {return atan2(__x, __y);}
+};
+
+template <class _Tp>
+struct __cos_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return cos(__x);}
+};
+
+template <class _Tp>
+struct __cosh_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return cosh(__x);}
+};
+
+template <class _Tp>
+struct __exp_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return exp(__x);}
+};
+
+template <class _Tp>
+struct __log_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return log(__x);}
+};
+
+template <class _Tp>
+struct __log10_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return log10(__x);}
+};
+
+template <class _Tp>
+struct __pow_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x, const _Tp& __y) const
+        {return pow(__x, __y);}
+};
+
+template <class _Tp>
+struct __sin_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return sin(__x);}
+};
+
+template <class _Tp>
+struct __sinh_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return sinh(__x);}
+};
+
+template <class _Tp>
+struct __sqrt_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return sqrt(__x);}
+};
+
+template <class _Tp>
+struct __tan_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return tan(__x);}
+};
+
+template <class _Tp>
+struct __tanh_expr
+{
+    typedef _Tp __result_type;
+    _LIBCPP_INLINE_VISIBILITY
+    _Tp operator()(const _Tp& __x) const
+        {return tanh(__x);}
+};
+
+template <class _ValExpr>
+class __slice_expr
+{
+    typedef typename remove_reference<_ValExpr>::type  _RmExpr;
+public:
+    typedef typename _RmExpr::value_type value_type;
+    typedef value_type __result_type;
+
+private:
+    _ValExpr __expr_;
+    size_t __start_;
+    size_t __size_;
+    size_t __stride_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __slice_expr(const slice& __sl, const _RmExpr& __e)
+        : __expr_(__e),
+          __start_(__sl.start()),
+          __size_(__sl.size()),
+          __stride_(__sl.stride())
+        {}
+public:
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type operator[](size_t __i) const
+        {return __expr_[__start_ + __i * __stride_];}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return __size_;}
+
+    template <class> friend class __val_expr;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS valarray;
+};
+
+template <class _ValExpr>
+class __mask_expr;
+
+template <class _ValExpr>
+class __indirect_expr;
+
+template <class _ValExpr>
+class __shift_expr
+{
+    typedef typename remove_reference<_ValExpr>::type  _RmExpr;
+public:
+    typedef typename _RmExpr::value_type value_type;
+    typedef value_type __result_type;
+
+private:
+    _ValExpr __expr_;
+    size_t __size_;
+    ptrdiff_t __ul_;
+    ptrdiff_t __sn_;
+    ptrdiff_t __n_;
+    static const ptrdiff_t _Np = static_cast<ptrdiff_t>(
+                                    sizeof(ptrdiff_t) * __CHAR_BIT__ - 1);
+
+    _LIBCPP_INLINE_VISIBILITY
+    __shift_expr(int __n, const _RmExpr& __e)
+        : __expr_(__e),
+          __size_(__e.size()),
+          __n_(__n)
+        {
+            ptrdiff_t __neg_n = static_cast<ptrdiff_t>(__n_ >> _Np);
+            __sn_ = __neg_n | static_cast<ptrdiff_t>(static_cast<size_t>(-__n_) >> _Np);
+            __ul_ = ((__size_ - __n_) & ~__neg_n) | ((__n_ + 1) & __neg_n);
+        }
+public:
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type operator[](size_t __j) const
+        {
+            ptrdiff_t __i = static_cast<ptrdiff_t>(__j);
+            ptrdiff_t __m = (__sn_ * __i - __ul_) >> _Np;
+            return (__expr_[(__i + __n_) & __m] & __m) | (value_type() & ~__m);
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return __size_;}
+
+    template <class> friend class __val_expr;
+};
+
+template <class _ValExpr>
+class __cshift_expr
+{
+    typedef typename remove_reference<_ValExpr>::type  _RmExpr;
+public:
+    typedef typename _RmExpr::value_type value_type;
+    typedef value_type __result_type;
+
+private:
+    _ValExpr __expr_;
+    size_t __size_;
+    size_t __m_;
+    size_t __o1_;
+    size_t __o2_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __cshift_expr(int __n, const _RmExpr& __e)
+        : __expr_(__e),
+          __size_(__e.size())
+        {
+            __n %= static_cast<int>(__size_);
+            if (__n >= 0)
+            {
+                __m_ = __size_ - __n;
+                __o1_ = __n;
+                __o2_ = __n - __size_;
+            }
+            else
+            {
+                __m_ = -__n;
+                __o1_ = __n + __size_;
+                __o2_ = __n;
+            }
+        }
+public:
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type operator[](size_t __i) const
+        {
+            if (__i < __m_)
+                return __expr_[__i + __o1_];
+            return __expr_[__i + __o2_];
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return __size_;}
+
+    template <class> friend class __val_expr;
+};
+
+template<class _ValExpr>
+class __val_expr;
+
+template<class _ValExpr>
+struct __is_val_expr : false_type {};
+
+template<class _ValExpr>
+struct __is_val_expr<__val_expr<_ValExpr> > : true_type {};
+
+template<class _Tp>
+struct __is_val_expr<valarray<_Tp> > : true_type {};
+
+template<class _Tp>
+class _LIBCPP_TEMPLATE_VIS valarray
+{
+public:
+    typedef _Tp value_type;
+    typedef _Tp __result_type;
+
+private:
+    value_type* __begin_;
+    value_type* __end_;
+
+public:
+    // construct/destroy:
+    _LIBCPP_INLINE_VISIBILITY
+    valarray() : __begin_(nullptr), __end_(nullptr) {}
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    explicit valarray(size_t __n);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray(const value_type& __x, size_t __n);
+    valarray(const value_type* __p, size_t __n);
+    valarray(const valarray& __v);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    valarray(valarray&& __v) _NOEXCEPT;
+    valarray(initializer_list<value_type> __il);
+#endif // _LIBCPP_CXX03_LANG
+    valarray(const slice_array<value_type>& __sa);
+    valarray(const gslice_array<value_type>& __ga);
+    valarray(const mask_array<value_type>& __ma);
+    valarray(const indirect_array<value_type>& __ia);
+    inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1
+    ~valarray();
+
+    // assignment:
+    valarray& operator=(const valarray& __v);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator=(valarray&& __v) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator=(initializer_list<value_type>);
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator=(const value_type& __x);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator=(const slice_array<value_type>& __sa);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator=(const gslice_array<value_type>& __ga);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator=(const mask_array<value_type>& __ma);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator=(const indirect_array<value_type>& __ia);
+    template <class _ValExpr>
+        _LIBCPP_INLINE_VISIBILITY
+        valarray& operator=(const __val_expr<_ValExpr>& __v);
+
+    // element access:
+    _LIBCPP_INLINE_VISIBILITY
+    const value_type& operator[](size_t __i) const {return __begin_[__i];}
+
+    _LIBCPP_INLINE_VISIBILITY
+    value_type&       operator[](size_t __i)       {return __begin_[__i];}
+
+    // subset operations:
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<__slice_expr<const valarray&> >    operator[](slice __s) const;
+    _LIBCPP_INLINE_VISIBILITY
+    slice_array<value_type>                       operator[](slice __s);
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<__indirect_expr<const valarray&> > operator[](const gslice& __gs) const;
+    _LIBCPP_INLINE_VISIBILITY
+    gslice_array<value_type>   operator[](const gslice& __gs);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<__indirect_expr<const valarray&> > operator[](gslice&& __gs) const;
+    _LIBCPP_INLINE_VISIBILITY
+    gslice_array<value_type>                      operator[](gslice&& __gs);
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<__mask_expr<const valarray&> >     operator[](const valarray<bool>& __vb) const;
+    _LIBCPP_INLINE_VISIBILITY
+    mask_array<value_type>                        operator[](const valarray<bool>& __vb);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<__mask_expr<const valarray&> >     operator[](valarray<bool>&& __vb) const;
+    _LIBCPP_INLINE_VISIBILITY
+    mask_array<value_type>                        operator[](valarray<bool>&& __vb);
+#endif // _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<__indirect_expr<const valarray&> > operator[](const valarray<size_t>& __vs) const;
+    _LIBCPP_INLINE_VISIBILITY
+    indirect_array<value_type>                    operator[](const valarray<size_t>& __vs);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<__indirect_expr<const valarray&> > operator[](valarray<size_t>&& __vs) const;
+    _LIBCPP_INLINE_VISIBILITY
+    indirect_array<value_type>                    operator[](valarray<size_t>&& __vs);
+#endif // _LIBCPP_CXX03_LANG
+
+    // unary operators:
+    valarray       operator+() const;
+    valarray       operator-() const;
+    valarray       operator~() const;
+    valarray<bool> operator!() const;
+
+    // computed assignment:
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator*= (const value_type& __x);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator/= (const value_type& __x);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator%= (const value_type& __x);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator+= (const value_type& __x);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator-= (const value_type& __x);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator^= (const value_type& __x);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator&= (const value_type& __x);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator|= (const value_type& __x);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator<<=(const value_type& __x);
+    _LIBCPP_INLINE_VISIBILITY
+    valarray& operator>>=(const value_type& __x);
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        valarray&
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator*= (const _Expr& __v);
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        valarray&
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator/= (const _Expr& __v);
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        valarray&
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator%= (const _Expr& __v);
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        valarray&
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator+= (const _Expr& __v);
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        valarray&
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator-= (const _Expr& __v);
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        valarray&
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator^= (const _Expr& __v);
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        valarray&
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator|= (const _Expr& __v);
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        valarray&
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator&= (const _Expr& __v);
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        valarray&
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator<<= (const _Expr& __v);
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        valarray&
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator>>= (const _Expr& __v);
+
+    // member functions:
+    _LIBCPP_INLINE_VISIBILITY
+    void swap(valarray& __v) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return static_cast<size_t>(__end_ - __begin_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    value_type sum() const;
+    _LIBCPP_INLINE_VISIBILITY
+    value_type min() const;
+    _LIBCPP_INLINE_VISIBILITY
+    value_type max() const;
+
+    valarray shift (int __i) const;
+    valarray cshift(int __i) const;
+    valarray apply(value_type __f(value_type)) const;
+    valarray apply(value_type __f(const value_type&)) const;
+    void     resize(size_t __n, value_type __x = value_type());
+
+private:
+    template <class> friend class _LIBCPP_TEMPLATE_VIS valarray;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS slice_array;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS gslice_array;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS mask_array;
+    template <class> friend class __mask_expr;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS indirect_array;
+    template <class> friend class __indirect_expr;
+    template <class> friend class __val_expr;
+
+    template <class _Up>
+    friend
+    _Up*
+    begin(valarray<_Up>& __v);
+
+    template <class _Up>
+    friend
+    const _Up*
+    begin(const valarray<_Up>& __v);
+
+    template <class _Up>
+    friend
+    _Up*
+    end(valarray<_Up>& __v);
+
+    template <class _Up>
+    friend
+    const _Up*
+    end(const valarray<_Up>& __v);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __clear(size_t __capacity);
+    valarray& __assign_range(const value_type* __f, const value_type* __l);
+};
+
+_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void valarray<size_t>::resize(size_t, size_t))
+
+template <class _Op, class _Tp>
+struct _UnaryOp<_Op, valarray<_Tp> >
+{
+    typedef typename _Op::__result_type __result_type;
+    typedef typename decay<__result_type>::type value_type;
+
+    _Op __op_;
+    const valarray<_Tp>& __a0_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _UnaryOp(const _Op& __op, const valarray<_Tp>& __a0) : __op_(__op), __a0_(__a0) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type operator[](size_t __i) const {return __op_(__a0_[__i]);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return __a0_.size();}
+};
+
+template <class _Op, class _Tp, class _A1>
+struct _BinaryOp<_Op, valarray<_Tp>, _A1>
+{
+    typedef typename _Op::__result_type __result_type;
+    typedef typename decay<__result_type>::type value_type;
+
+    _Op __op_;
+    const valarray<_Tp>& __a0_;
+    _A1 __a1_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _BinaryOp(const _Op& __op, const valarray<_Tp>& __a0, const _A1& __a1)
+        : __op_(__op), __a0_(__a0), __a1_(__a1) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type operator[](size_t __i) const {return __op_(__a0_[__i], __a1_[__i]);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return __a0_.size();}
+};
+
+template <class _Op, class _A0, class _Tp>
+struct _BinaryOp<_Op, _A0, valarray<_Tp> >
+{
+    typedef typename _Op::__result_type __result_type;
+    typedef typename decay<__result_type>::type value_type;
+
+    _Op __op_;
+    _A0 __a0_;
+    const valarray<_Tp>& __a1_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _BinaryOp(const _Op& __op, const _A0& __a0, const valarray<_Tp>& __a1)
+        : __op_(__op), __a0_(__a0), __a1_(__a1) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type operator[](size_t __i) const {return __op_(__a0_[__i], __a1_[__i]);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return __a0_.size();}
+};
+
+template <class _Op, class _Tp>
+struct _BinaryOp<_Op, valarray<_Tp>, valarray<_Tp> >
+{
+    typedef typename _Op::__result_type __result_type;
+    typedef typename decay<__result_type>::type value_type;
+
+    _Op __op_;
+    const valarray<_Tp>& __a0_;
+    const valarray<_Tp>& __a1_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    _BinaryOp(const _Op& __op, const valarray<_Tp>& __a0, const valarray<_Tp>& __a1)
+        : __op_(__op), __a0_(__a0), __a1_(__a1) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type operator[](size_t __i) const {return __op_(__a0_[__i], __a1_[__i]);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return __a0_.size();}
+};
+
+// slice_array
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS slice_array
+{
+public:
+    typedef _Tp value_type;
+
+private:
+    value_type* __vp_;
+    size_t __size_;
+    size_t __stride_;
+
+public:
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator*=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator/=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator%=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator+=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator-=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator^=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator&=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator|=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator<<=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator>>=(const _Expr& __v) const;
+
+    slice_array(slice_array const&) = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    const slice_array& operator=(const slice_array& __sa) const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator=(const value_type& __x) const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator=(const valarray<value_type>& __va) const;
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    slice_array(const slice& __sl, const valarray<value_type>& __v)
+        : __vp_(const_cast<value_type*>(__v.__begin_ + __sl.start())),
+          __size_(__sl.size()),
+          __stride_(__sl.stride())
+        {}
+
+    template <class> friend class valarray;
+    template <class> friend class sliceExpr;
+};
+
+template <class _Tp>
+inline
+const slice_array<_Tp>&
+slice_array<_Tp>::operator=(const slice_array& __sa) const
+{
+    value_type* __t = __vp_;
+    const value_type* __s = __sa.__vp_;
+    for (size_t __n = __size_; __n; --__n, __t += __stride_, __s += __sa.__stride_)
+        *__t = *__s;
+    return *this;
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+slice_array<_Tp>::operator=(const _Expr& __v) const
+{
+    value_type* __t = __vp_;
+    for (size_t __i = 0; __i < __size_; ++__i, __t += __stride_)
+        *__t = __v[__i];
+}
+
+template <class _Tp>
+inline void
+slice_array<_Tp>::operator=(const valarray<value_type>& __va) const
+{
+    value_type* __t = __vp_;
+    for (size_t __i = 0; __i < __va.size(); ++__i, __t += __stride_)
+        *__t = __va[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+slice_array<_Tp>::operator*=(const _Expr& __v) const
+{
+    value_type* __t = __vp_;
+    for (size_t __i = 0; __i < __size_; ++__i, __t += __stride_)
+        *__t *= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+slice_array<_Tp>::operator/=(const _Expr& __v) const
+{
+    value_type* __t = __vp_;
+    for (size_t __i = 0; __i < __size_; ++__i, __t += __stride_)
+        *__t /= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+slice_array<_Tp>::operator%=(const _Expr& __v) const
+{
+    value_type* __t = __vp_;
+    for (size_t __i = 0; __i < __size_; ++__i, __t += __stride_)
+        *__t %= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+slice_array<_Tp>::operator+=(const _Expr& __v) const
+{
+    value_type* __t = __vp_;
+    for (size_t __i = 0; __i < __size_; ++__i, __t += __stride_)
+        *__t += __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+slice_array<_Tp>::operator-=(const _Expr& __v) const
+{
+    value_type* __t = __vp_;
+    for (size_t __i = 0; __i < __size_; ++__i, __t += __stride_)
+        *__t -= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+slice_array<_Tp>::operator^=(const _Expr& __v) const
+{
+    value_type* __t = __vp_;
+    for (size_t __i = 0; __i < __size_; ++__i, __t += __stride_)
+        *__t ^= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+slice_array<_Tp>::operator&=(const _Expr& __v) const
+{
+    value_type* __t = __vp_;
+    for (size_t __i = 0; __i < __size_; ++__i, __t += __stride_)
+        *__t &= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+slice_array<_Tp>::operator|=(const _Expr& __v) const
+{
+    value_type* __t = __vp_;
+    for (size_t __i = 0; __i < __size_; ++__i, __t += __stride_)
+        *__t |= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+slice_array<_Tp>::operator<<=(const _Expr& __v) const
+{
+    value_type* __t = __vp_;
+    for (size_t __i = 0; __i < __size_; ++__i, __t += __stride_)
+        *__t <<= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+slice_array<_Tp>::operator>>=(const _Expr& __v) const
+{
+    value_type* __t = __vp_;
+    for (size_t __i = 0; __i < __size_; ++__i, __t += __stride_)
+        *__t >>= __v[__i];
+}
+
+template <class _Tp>
+inline
+void
+slice_array<_Tp>::operator=(const value_type& __x) const
+{
+    value_type* __t = __vp_;
+    for (size_t __n = __size_; __n; --__n, __t += __stride_)
+        *__t = __x;
+}
+
+// gslice
+
+class _LIBCPP_TYPE_VIS gslice
+{
+    valarray<size_t> __size_;
+    valarray<size_t> __stride_;
+    valarray<size_t> __1d_;
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    gslice() {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    gslice(size_t __start, const valarray<size_t>& __size,
+                           const valarray<size_t>& __stride)
+        : __size_(__size),
+          __stride_(__stride)
+        {__init(__start);}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    gslice(size_t __start, const valarray<size_t>&  __size,
+                                 valarray<size_t>&& __stride)
+        : __size_(__size),
+          __stride_(move(__stride))
+        {__init(__start);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    gslice(size_t __start,       valarray<size_t>&& __size,
+                           const valarray<size_t>&  __stride)
+        : __size_(move(__size)),
+          __stride_(__stride)
+        {__init(__start);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    gslice(size_t __start,       valarray<size_t>&& __size,
+                                 valarray<size_t>&& __stride)
+        : __size_(move(__size)),
+          __stride_(move(__stride))
+        {__init(__start);}
+
+#endif // _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t           start()  const {return __1d_.size() ? __1d_[0] : 0;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    valarray<size_t> size()   const {return __size_;}
+
+    _LIBCPP_INLINE_VISIBILITY
+    valarray<size_t> stride() const {return __stride_;}
+
+private:
+    void __init(size_t __start);
+
+    template <class> friend class gslice_array;
+    template <class> friend class valarray;
+    template <class> friend class __val_expr;
+};
+
+// gslice_array
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS gslice_array
+{
+public:
+    typedef _Tp value_type;
+
+private:
+    value_type*      __vp_;
+    valarray<size_t> __1d_;
+
+public:
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator*=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator/=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator%=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator+=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator-=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator^=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator&=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator|=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator<<=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator>>=(const _Expr& __v) const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    const gslice_array& operator=(const gslice_array& __ga) const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator=(const value_type& __x) const;
+
+    gslice_array(const gslice_array&)            = default;
+
+private:
+    gslice_array(const gslice& __gs, const valarray<value_type>& __v)
+        : __vp_(const_cast<value_type*>(__v.__begin_)),
+          __1d_(__gs.__1d_)
+        {}
+
+#ifndef _LIBCPP_CXX03_LANG
+    gslice_array(gslice&& __gs, const valarray<value_type>& __v)
+        : __vp_(const_cast<value_type*>(__v.__begin_)),
+          __1d_(move(__gs.__1d_))
+        {}
+#endif // _LIBCPP_CXX03_LANG
+
+    template <class> friend class valarray;
+};
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+gslice_array<_Tp>::operator=(const _Expr& __v) const
+{
+    typedef const size_t* _Ip;
+    size_t __j = 0;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_; __i != __e; ++__i, ++__j)
+        __vp_[*__i] = __v[__j];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+gslice_array<_Tp>::operator*=(const _Expr& __v) const
+{
+    typedef const size_t* _Ip;
+    size_t __j = 0;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_; __i != __e; ++__i, ++__j)
+        __vp_[*__i] *= __v[__j];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+gslice_array<_Tp>::operator/=(const _Expr& __v) const
+{
+    typedef const size_t* _Ip;
+    size_t __j = 0;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_; __i != __e; ++__i, ++__j)
+        __vp_[*__i] /= __v[__j];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+gslice_array<_Tp>::operator%=(const _Expr& __v) const
+{
+    typedef const size_t* _Ip;
+    size_t __j = 0;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_; __i != __e; ++__i, ++__j)
+        __vp_[*__i] %= __v[__j];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+gslice_array<_Tp>::operator+=(const _Expr& __v) const
+{
+    typedef const size_t* _Ip;
+    size_t __j = 0;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_; __i != __e; ++__i, ++__j)
+        __vp_[*__i] += __v[__j];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+gslice_array<_Tp>::operator-=(const _Expr& __v) const
+{
+    typedef const size_t* _Ip;
+    size_t __j = 0;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_; __i != __e; ++__i, ++__j)
+        __vp_[*__i] -= __v[__j];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+gslice_array<_Tp>::operator^=(const _Expr& __v) const
+{
+    typedef const size_t* _Ip;
+    size_t __j = 0;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_; __i != __e; ++__i, ++__j)
+        __vp_[*__i] ^= __v[__j];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+gslice_array<_Tp>::operator&=(const _Expr& __v) const
+{
+    typedef const size_t* _Ip;
+    size_t __j = 0;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_; __i != __e; ++__i, ++__j)
+        __vp_[*__i] &= __v[__j];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+gslice_array<_Tp>::operator|=(const _Expr& __v) const
+{
+    typedef const size_t* _Ip;
+    size_t __j = 0;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_; __i != __e; ++__i, ++__j)
+        __vp_[*__i] |= __v[__j];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+gslice_array<_Tp>::operator<<=(const _Expr& __v) const
+{
+    typedef const size_t* _Ip;
+    size_t __j = 0;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_; __i != __e; ++__i, ++__j)
+        __vp_[*__i] <<= __v[__j];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+gslice_array<_Tp>::operator>>=(const _Expr& __v) const
+{
+    typedef const size_t* _Ip;
+    size_t __j = 0;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_; __i != __e; ++__i, ++__j)
+        __vp_[*__i] >>= __v[__j];
+}
+
+template <class _Tp>
+inline
+const gslice_array<_Tp>&
+gslice_array<_Tp>::operator=(const gslice_array& __ga) const
+{
+    typedef const size_t* _Ip;
+    const value_type* __s = __ga.__vp_;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_, __j = __ga.__1d_.__begin_;
+            __i != __e; ++__i, ++__j)
+        __vp_[*__i] = __s[*__j];
+    return *this;
+}
+
+template <class _Tp>
+inline
+void
+gslice_array<_Tp>::operator=(const value_type& __x) const
+{
+    typedef const size_t* _Ip;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_; __i != __e; ++__i)
+        __vp_[*__i] = __x;
+}
+
+// mask_array
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS mask_array
+{
+public:
+    typedef _Tp value_type;
+
+private:
+    value_type*      __vp_;
+    valarray<size_t> __1d_;
+
+public:
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator*=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator/=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator%=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator+=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator-=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator^=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator&=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator|=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator<<=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator>>=(const _Expr& __v) const;
+
+    mask_array(const mask_array&) = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    const mask_array& operator=(const mask_array& __ma) const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator=(const value_type& __x) const;
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    mask_array(const valarray<bool>& __vb, const valarray<value_type>& __v)
+        : __vp_(const_cast<value_type*>(__v.__begin_)),
+          __1d_(static_cast<size_t>(count(__vb.__begin_, __vb.__end_, true)))
+          {
+              size_t __j = 0;
+              for (size_t __i = 0; __i < __vb.size(); ++__i)
+                  if (__vb[__i])
+                      __1d_[__j++] = __i;
+          }
+
+    template <class> friend class valarray;
+};
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+mask_array<_Tp>::operator=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] = __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+mask_array<_Tp>::operator*=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] *= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+mask_array<_Tp>::operator/=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] /= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+mask_array<_Tp>::operator%=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] %= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+mask_array<_Tp>::operator+=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] += __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+mask_array<_Tp>::operator-=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] -= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+mask_array<_Tp>::operator^=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] ^= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+mask_array<_Tp>::operator&=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] &= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+mask_array<_Tp>::operator|=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] |= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+mask_array<_Tp>::operator<<=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] <<= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+mask_array<_Tp>::operator>>=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] >>= __v[__i];
+}
+
+template <class _Tp>
+inline
+const mask_array<_Tp>&
+mask_array<_Tp>::operator=(const mask_array& __ma) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] = __ma.__vp_[__1d_[__i]];
+    return *this;
+}
+
+template <class _Tp>
+inline
+void
+mask_array<_Tp>::operator=(const value_type& __x) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] = __x;
+}
+
+template <class _ValExpr>
+class __mask_expr
+{
+    typedef typename remove_reference<_ValExpr>::type  _RmExpr;
+public:
+    typedef typename _RmExpr::value_type value_type;
+    typedef value_type __result_type;
+
+private:
+    _ValExpr __expr_;
+    valarray<size_t> __1d_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __mask_expr(const valarray<bool>& __vb, const _RmExpr& __e)
+        : __expr_(__e),
+          __1d_(static_cast<size_t>(count(__vb.__begin_, __vb.__end_, true)))
+          {
+              size_t __j = 0;
+              for (size_t __i = 0; __i < __vb.size(); ++__i)
+                  if (__vb[__i])
+                      __1d_[__j++] = __i;
+          }
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type operator[](size_t __i) const
+        {return __expr_[__1d_[__i]];}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return __1d_.size();}
+
+    template <class> friend class __val_expr;
+    template <class> friend class valarray;
+};
+
+// indirect_array
+
+template <class _Tp>
+class _LIBCPP_TEMPLATE_VIS indirect_array
+{
+public:
+    typedef _Tp value_type;
+
+private:
+    value_type*      __vp_;
+    valarray<size_t> __1d_;
+
+public:
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator*=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator/=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator%=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator+=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator-=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator^=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator&=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator|=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator<<=(const _Expr& __v) const;
+
+    template <class _Expr>
+    typename enable_if
+    <
+        __is_val_expr<_Expr>::value,
+        void
+    >::type
+    _LIBCPP_INLINE_VISIBILITY
+    operator>>=(const _Expr& __v) const;
+
+    indirect_array(const indirect_array&) = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    const indirect_array& operator=(const indirect_array& __ia) const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void operator=(const value_type& __x) const;
+
+private:
+     _LIBCPP_INLINE_VISIBILITY
+   indirect_array(const valarray<size_t>& __ia, const valarray<value_type>& __v)
+        : __vp_(const_cast<value_type*>(__v.__begin_)),
+          __1d_(__ia)
+        {}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    indirect_array(valarray<size_t>&& __ia, const valarray<value_type>& __v)
+        : __vp_(const_cast<value_type*>(__v.__begin_)),
+          __1d_(move(__ia))
+        {}
+
+#endif // _LIBCPP_CXX03_LANG
+
+    template <class> friend class valarray;
+};
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+indirect_array<_Tp>::operator=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] = __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+indirect_array<_Tp>::operator*=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] *= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+indirect_array<_Tp>::operator/=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] /= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+indirect_array<_Tp>::operator%=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] %= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+indirect_array<_Tp>::operator+=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] += __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+indirect_array<_Tp>::operator-=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] -= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+indirect_array<_Tp>::operator^=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] ^= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+indirect_array<_Tp>::operator&=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] &= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+indirect_array<_Tp>::operator|=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] |= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+indirect_array<_Tp>::operator<<=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] <<= __v[__i];
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    void
+>::type
+indirect_array<_Tp>::operator>>=(const _Expr& __v) const
+{
+    size_t __n = __1d_.size();
+    for (size_t __i = 0; __i < __n; ++__i)
+        __vp_[__1d_[__i]] >>= __v[__i];
+}
+
+template <class _Tp>
+inline
+const indirect_array<_Tp>&
+indirect_array<_Tp>::operator=(const indirect_array& __ia) const
+{
+    typedef const size_t* _Ip;
+    const value_type* __s = __ia.__vp_;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_, __j = __ia.__1d_.__begin_;
+            __i != __e; ++__i, ++__j)
+        __vp_[*__i] = __s[*__j];
+    return *this;
+}
+
+template <class _Tp>
+inline
+void
+indirect_array<_Tp>::operator=(const value_type& __x) const
+{
+    typedef const size_t* _Ip;
+    for (_Ip __i = __1d_.__begin_, __e = __1d_.__end_; __i != __e; ++__i)
+        __vp_[*__i] = __x;
+}
+
+template <class _ValExpr>
+class __indirect_expr
+{
+    typedef typename remove_reference<_ValExpr>::type  _RmExpr;
+public:
+    typedef typename _RmExpr::value_type value_type;
+    typedef value_type __result_type;
+
+private:
+    _ValExpr __expr_;
+    valarray<size_t> __1d_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    __indirect_expr(const valarray<size_t>& __ia, const _RmExpr& __e)
+        : __expr_(__e),
+          __1d_(__ia)
+          {}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    __indirect_expr(valarray<size_t>&& __ia, const _RmExpr& __e)
+        : __expr_(__e),
+          __1d_(move(__ia))
+          {}
+
+#endif // _LIBCPP_CXX03_LANG
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type operator[](size_t __i) const
+        {return __expr_[__1d_[__i]];}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return __1d_.size();}
+
+    template <class> friend class __val_expr;
+    template <class> friend class _LIBCPP_TEMPLATE_VIS valarray;
+};
+
+template<class _ValExpr>
+class __val_expr
+{
+    typedef typename remove_reference<_ValExpr>::type  _RmExpr;
+
+    _ValExpr __expr_;
+public:
+    typedef typename _RmExpr::value_type value_type;
+    typedef typename _RmExpr::__result_type __result_type;
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __val_expr(const _RmExpr& __e) : __expr_(__e) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type operator[](size_t __i) const
+        {return __expr_[__i];}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<__slice_expr<_ValExpr> > operator[](slice __s) const
+    {
+        typedef __slice_expr<_ValExpr> _NewExpr;
+        return __val_expr< _NewExpr >(_NewExpr(__s, __expr_));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<__indirect_expr<_ValExpr> > operator[](const gslice& __gs) const
+    {
+        typedef __indirect_expr<_ValExpr> _NewExpr;
+        return __val_expr<_NewExpr >(_NewExpr(__gs.__1d_, __expr_));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<__mask_expr<_ValExpr> > operator[](const valarray<bool>& __vb) const
+    {
+        typedef __mask_expr<_ValExpr> _NewExpr;
+        return __val_expr< _NewExpr >( _NewExpr(__vb, __expr_));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<__indirect_expr<_ValExpr> > operator[](const valarray<size_t>& __vs) const
+    {
+        typedef __indirect_expr<_ValExpr> _NewExpr;
+        return __val_expr< _NewExpr >(_NewExpr(__vs, __expr_));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<_UnaryOp<__unary_plus<value_type>, _ValExpr> >
+    operator+() const
+    {
+        typedef _UnaryOp<__unary_plus<value_type>, _ValExpr> _NewExpr;
+        return __val_expr<_NewExpr>(_NewExpr(__unary_plus<value_type>(), __expr_));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<_UnaryOp<negate<value_type>, _ValExpr> >
+    operator-() const
+    {
+        typedef _UnaryOp<negate<value_type>, _ValExpr> _NewExpr;
+        return __val_expr<_NewExpr>(_NewExpr(negate<value_type>(), __expr_));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<_UnaryOp<__bit_not<value_type>, _ValExpr> >
+    operator~() const
+    {
+        typedef _UnaryOp<__bit_not<value_type>, _ValExpr> _NewExpr;
+        return __val_expr<_NewExpr>(_NewExpr(__bit_not<value_type>(), __expr_));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<_UnaryOp<logical_not<value_type>, _ValExpr> >
+    operator!() const
+    {
+        typedef _UnaryOp<logical_not<value_type>, _ValExpr> _NewExpr;
+        return __val_expr<_NewExpr>(_NewExpr(logical_not<value_type>(), __expr_));
+    }
+
+    operator valarray<__result_type>() const;
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_t size() const {return __expr_.size();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type sum() const
+    {
+        size_t __n = __expr_.size();
+        __result_type __r = __n ? __expr_[0] : __result_type();
+        for (size_t __i = 1; __i < __n; ++__i)
+            __r += __expr_[__i];
+        return __r;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type min() const
+    {
+        size_t __n = size();
+        __result_type __r = __n ? (*this)[0] : __result_type();
+        for (size_t __i = 1; __i < __n; ++__i)
+        {
+            __result_type __x = __expr_[__i];
+            if (__x < __r)
+                __r = __x;
+        }
+        return __r;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __result_type max() const
+    {
+        size_t __n = size();
+        __result_type __r = __n ? (*this)[0] : __result_type();
+        for (size_t __i = 1; __i < __n; ++__i)
+        {
+            __result_type __x = __expr_[__i];
+            if (__r < __x)
+                __r = __x;
+        }
+        return __r;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<__shift_expr<_ValExpr> > shift (int __i) const
+        {return __val_expr<__shift_expr<_ValExpr> >(__shift_expr<_ValExpr>(__i, __expr_));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<__cshift_expr<_ValExpr> > cshift(int __i) const
+        {return __val_expr<__cshift_expr<_ValExpr> >(__cshift_expr<_ValExpr>(__i, __expr_));}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<_UnaryOp<__apply_expr<value_type, value_type(*)(value_type)>, _ValExpr> >
+    apply(value_type __f(value_type)) const
+    {
+        typedef __apply_expr<value_type, value_type(*)(value_type)> _Op;
+        typedef _UnaryOp<_Op, _ValExpr> _NewExpr;
+        return __val_expr<_NewExpr>(_NewExpr(_Op(__f), __expr_));
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    __val_expr<_UnaryOp<__apply_expr<value_type, value_type(*)(const value_type&)>, _ValExpr> >
+    apply(value_type __f(const value_type&)) const
+    {
+        typedef __apply_expr<value_type, value_type(*)(const value_type&)> _Op;
+        typedef _UnaryOp<_Op, _ValExpr> _NewExpr;
+        return __val_expr<_NewExpr>(_NewExpr(_Op(__f), __expr_));
+    }
+};
+
+template<class _ValExpr>
+__val_expr<_ValExpr>::operator valarray<typename __val_expr<_ValExpr>::__result_type>() const
+{
+    valarray<__result_type> __r;
+    size_t __n = __expr_.size();
+    if (__n)
+    {
+        __r.__begin_ =
+            __r.__end_ = allocator<__result_type>().allocate(__n);
+        for (size_t __i = 0; __i != __n; ++__r.__end_, ++__i)
+            ::new ((void*)__r.__end_) __result_type(__expr_[__i]);
+    }
+    return __r;
+}
+
+// valarray
+
+template <class _Tp>
+inline
+valarray<_Tp>::valarray(size_t __n)
+    : __begin_(nullptr),
+      __end_(nullptr)
+{
+    if (__n)
+    {
+        __begin_ = __end_ = allocator<value_type>().allocate(__n);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (size_t __n_left = __n; __n_left; --__n_left, ++__end_)
+                ::new ((void*)__end_) value_type();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __clear(__n);
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>::valarray(const value_type& __x, size_t __n)
+    : __begin_(nullptr),
+      __end_(nullptr)
+{
+    resize(__n, __x);
+}
+
+template <class _Tp>
+valarray<_Tp>::valarray(const value_type* __p, size_t __n)
+    : __begin_(nullptr),
+      __end_(nullptr)
+{
+    if (__n)
+    {
+        __begin_ = __end_ = allocator<value_type>().allocate(__n);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (size_t __n_left = __n; __n_left; ++__end_, ++__p, --__n_left)
+                ::new ((void*)__end_) value_type(*__p);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __clear(__n);
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+}
+
+template <class _Tp>
+valarray<_Tp>::valarray(const valarray& __v)
+    : __begin_(nullptr),
+      __end_(nullptr)
+{
+    if (__v.size())
+    {
+        __begin_ = __end_ = allocator<value_type>().allocate(__v.size());
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (value_type* __p = __v.__begin_; __p != __v.__end_; ++__end_, ++__p)
+                ::new ((void*)__end_) value_type(*__p);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __clear(__v.size());
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp>
+inline
+valarray<_Tp>::valarray(valarray&& __v) _NOEXCEPT
+    : __begin_(__v.__begin_),
+      __end_(__v.__end_)
+{
+    __v.__begin_ = __v.__end_ = nullptr;
+}
+
+template <class _Tp>
+valarray<_Tp>::valarray(initializer_list<value_type> __il)
+    : __begin_(nullptr),
+      __end_(nullptr)
+{
+    const size_t __n = __il.size();
+    if (__n)
+    {
+        __begin_ = __end_ = allocator<value_type>().allocate(__n);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            size_t __n_left = __n;
+            for (const value_type* __p = __il.begin(); __n_left; ++__end_, ++__p, --__n_left)
+                ::new ((void*)__end_) value_type(*__p);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __clear(__n);
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp>
+valarray<_Tp>::valarray(const slice_array<value_type>& __sa)
+    : __begin_(nullptr),
+      __end_(nullptr)
+{
+    const size_t __n = __sa.__size_;
+    if (__n)
+    {
+        __begin_ = __end_ = allocator<value_type>().allocate(__n);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            size_t __n_left = __n;
+            for (const value_type* __p = __sa.__vp_; __n_left; ++__end_, __p += __sa.__stride_, --__n_left)
+                ::new ((void*)__end_) value_type(*__p);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __clear(__n);
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+}
+
+template <class _Tp>
+valarray<_Tp>::valarray(const gslice_array<value_type>& __ga)
+    : __begin_(nullptr),
+      __end_(nullptr)
+{
+    const size_t __n = __ga.__1d_.size();
+    if (__n)
+    {
+        __begin_ = __end_ = allocator<value_type>().allocate(__n);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            typedef const size_t* _Ip;
+            const value_type* __s = __ga.__vp_;
+            for (_Ip __i = __ga.__1d_.__begin_, __e = __ga.__1d_.__end_;
+                    __i != __e; ++__i, ++__end_)
+                ::new ((void*)__end_) value_type(__s[*__i]);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __clear(__n);
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+}
+
+template <class _Tp>
+valarray<_Tp>::valarray(const mask_array<value_type>& __ma)
+    : __begin_(nullptr),
+      __end_(nullptr)
+{
+    const size_t __n = __ma.__1d_.size();
+    if (__n)
+    {
+        __begin_ = __end_ = allocator<value_type>().allocate(__n);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            typedef const size_t* _Ip;
+            const value_type* __s = __ma.__vp_;
+            for (_Ip __i = __ma.__1d_.__begin_, __e = __ma.__1d_.__end_;
+                    __i != __e; ++__i, ++__end_)
+                ::new ((void*)__end_) value_type(__s[*__i]);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __clear(__n);
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+}
+
+template <class _Tp>
+valarray<_Tp>::valarray(const indirect_array<value_type>& __ia)
+    : __begin_(nullptr),
+      __end_(nullptr)
+{
+    const size_t __n = __ia.__1d_.size();
+    if (__n)
+    {
+        __begin_ = __end_ = allocator<value_type>().allocate(__n);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            typedef const size_t* _Ip;
+            const value_type* __s = __ia.__vp_;
+            for (_Ip __i = __ia.__1d_.__begin_, __e = __ia.__1d_.__end_;
+                    __i != __e; ++__i, ++__end_)
+                ::new ((void*)__end_) value_type(__s[*__i]);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __clear(__n);
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>::~valarray()
+{
+    __clear(size());
+}
+
+template <class _Tp>
+valarray<_Tp>&
+valarray<_Tp>::__assign_range(const value_type* __f, const value_type* __l)
+{
+    size_t __n = __l - __f;
+    if (size() != __n)
+    {
+        __clear(size());
+        __begin_ = allocator<value_type>().allocate(__n);
+        __end_ = __begin_ + __n;
+        _VSTD::uninitialized_copy(__f, __l, __begin_);
+    } else {
+        _VSTD::copy(__f, __l, __begin_);
+    }
+    return *this;
+}
+
+template <class _Tp>
+valarray<_Tp>&
+valarray<_Tp>::operator=(const valarray& __v)
+{
+    if (this != _VSTD::addressof(__v))
+        return __assign_range(__v.__begin_, __v.__end_);
+    return *this;
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator=(valarray&& __v) _NOEXCEPT
+{
+    __clear(size());
+    __begin_ = __v.__begin_;
+    __end_ = __v.__end_;
+    __v.__begin_ = nullptr;
+    __v.__end_ = nullptr;
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator=(initializer_list<value_type> __il)
+{
+    return __assign_range(__il.begin(), __il.end());
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator=(const value_type& __x)
+{
+    _VSTD::fill(__begin_, __end_, __x);
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator=(const slice_array<value_type>& __sa)
+{
+    value_type* __t = __begin_;
+    const value_type* __s = __sa.__vp_;
+    for (size_t __n = __sa.__size_; __n; --__n, __s += __sa.__stride_, ++__t)
+        *__t = *__s;
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator=(const gslice_array<value_type>& __ga)
+{
+    typedef const size_t* _Ip;
+    value_type* __t = __begin_;
+    const value_type* __s = __ga.__vp_;
+    for (_Ip __i = __ga.__1d_.__begin_, __e = __ga.__1d_.__end_;
+                    __i != __e; ++__i, ++__t)
+        *__t = __s[*__i];
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator=(const mask_array<value_type>& __ma)
+{
+    typedef const size_t* _Ip;
+    value_type* __t = __begin_;
+    const value_type* __s = __ma.__vp_;
+    for (_Ip __i = __ma.__1d_.__begin_, __e = __ma.__1d_.__end_;
+                    __i != __e; ++__i, ++__t)
+        *__t = __s[*__i];
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator=(const indirect_array<value_type>& __ia)
+{
+    typedef const size_t* _Ip;
+    value_type* __t = __begin_;
+    const value_type* __s = __ia.__vp_;
+    for (_Ip __i = __ia.__1d_.__begin_, __e = __ia.__1d_.__end_;
+                    __i != __e; ++__i, ++__t)
+        *__t = __s[*__i];
+    return *this;
+}
+
+template <class _Tp>
+template <class _ValExpr>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator=(const __val_expr<_ValExpr>& __v)
+{
+    size_t __n = __v.size();
+    if (size() != __n)
+        resize(__n);
+    value_type* __t = __begin_;
+    for (size_t __i = 0; __i != __n; ++__t, ++__i)
+        *__t = __result_type(__v[__i]);
+    return *this;
+}
+
+template <class _Tp>
+inline
+__val_expr<__slice_expr<const valarray<_Tp>&> >
+valarray<_Tp>::operator[](slice __s) const
+{
+    return __val_expr<__slice_expr<const valarray&> >(__slice_expr<const valarray&>(__s, *this));
+}
+
+template <class _Tp>
+inline
+slice_array<_Tp>
+valarray<_Tp>::operator[](slice __s)
+{
+    return slice_array<value_type>(__s, *this);
+}
+
+template <class _Tp>
+inline
+__val_expr<__indirect_expr<const valarray<_Tp>&> >
+valarray<_Tp>::operator[](const gslice& __gs) const
+{
+    return __val_expr<__indirect_expr<const valarray&> >(__indirect_expr<const valarray&>(__gs.__1d_, *this));
+}
+
+template <class _Tp>
+inline
+gslice_array<_Tp>
+valarray<_Tp>::operator[](const gslice& __gs)
+{
+    return gslice_array<value_type>(__gs, *this);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp>
+inline
+__val_expr<__indirect_expr<const valarray<_Tp>&> >
+valarray<_Tp>::operator[](gslice&& __gs) const
+{
+    return __val_expr<__indirect_expr<const valarray&> >(__indirect_expr<const valarray&>(move(__gs.__1d_), *this));
+}
+
+template <class _Tp>
+inline
+gslice_array<_Tp>
+valarray<_Tp>::operator[](gslice&& __gs)
+{
+    return gslice_array<value_type>(move(__gs), *this);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp>
+inline
+__val_expr<__mask_expr<const valarray<_Tp>&> >
+valarray<_Tp>::operator[](const valarray<bool>& __vb) const
+{
+    return __val_expr<__mask_expr<const valarray&> >(__mask_expr<const valarray&>(__vb, *this));
+}
+
+template <class _Tp>
+inline
+mask_array<_Tp>
+valarray<_Tp>::operator[](const valarray<bool>& __vb)
+{
+    return mask_array<value_type>(__vb, *this);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp>
+inline
+__val_expr<__mask_expr<const valarray<_Tp>&> >
+valarray<_Tp>::operator[](valarray<bool>&& __vb) const
+{
+    return __val_expr<__mask_expr<const valarray&> >(__mask_expr<const valarray&>(move(__vb), *this));
+}
+
+template <class _Tp>
+inline
+mask_array<_Tp>
+valarray<_Tp>::operator[](valarray<bool>&& __vb)
+{
+    return mask_array<value_type>(move(__vb), *this);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp>
+inline
+__val_expr<__indirect_expr<const valarray<_Tp>&> >
+valarray<_Tp>::operator[](const valarray<size_t>& __vs) const
+{
+    return __val_expr<__indirect_expr<const valarray&> >(__indirect_expr<const valarray&>(__vs, *this));
+}
+
+template <class _Tp>
+inline
+indirect_array<_Tp>
+valarray<_Tp>::operator[](const valarray<size_t>& __vs)
+{
+    return indirect_array<value_type>(__vs, *this);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp>
+inline
+__val_expr<__indirect_expr<const valarray<_Tp>&> >
+valarray<_Tp>::operator[](valarray<size_t>&& __vs) const
+{
+    return __val_expr<__indirect_expr<const valarray&> >(__indirect_expr<const valarray&>(move(__vs), *this));
+}
+
+template <class _Tp>
+inline
+indirect_array<_Tp>
+valarray<_Tp>::operator[](valarray<size_t>&& __vs)
+{
+    return indirect_array<value_type>(move(__vs), *this);
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Tp>
+valarray<_Tp>
+valarray<_Tp>::operator+() const
+{
+    valarray<value_type> __r;
+    size_t __n = size();
+    if (__n)
+    {
+        __r.__begin_ = __r.__end_ = allocator<value_type>().allocate(__n);
+        for (const value_type* __p = __begin_; __n; ++__r.__end_, ++__p, --__n)
+            ::new ((void*)__r.__end_) value_type(+*__p);
+    }
+    return __r;
+}
+
+template <class _Tp>
+valarray<_Tp>
+valarray<_Tp>::operator-() const
+{
+    valarray<value_type> __r;
+    size_t __n = size();
+    if (__n)
+    {
+        __r.__begin_ = __r.__end_ = allocator<value_type>().allocate(__n);
+        for (const value_type* __p = __begin_; __n; ++__r.__end_, ++__p, --__n)
+            ::new ((void*)__r.__end_) value_type(-*__p);
+    }
+    return __r;
+}
+
+template <class _Tp>
+valarray<_Tp>
+valarray<_Tp>::operator~() const
+{
+    valarray<value_type> __r;
+    size_t __n = size();
+    if (__n)
+    {
+        __r.__begin_ = __r.__end_ = allocator<value_type>().allocate(__n);
+        for (const value_type* __p = __begin_; __n; ++__r.__end_, ++__p, --__n)
+            ::new ((void*)__r.__end_) value_type(~*__p);
+    }
+    return __r;
+}
+
+template <class _Tp>
+valarray<bool>
+valarray<_Tp>::operator!() const
+{
+    valarray<bool> __r;
+    size_t __n = size();
+    if (__n)
+    {
+        __r.__begin_ = __r.__end_ = allocator<bool>().allocate(__n);
+        for (const value_type* __p = __begin_; __n; ++__r.__end_, ++__p, --__n)
+            ::new ((void*)__r.__end_) bool(!*__p);
+    }
+    return __r;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator*=(const value_type& __x)
+{
+    for (value_type* __p = __begin_; __p != __end_; ++__p)
+        *__p *= __x;
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator/=(const value_type& __x)
+{
+    for (value_type* __p = __begin_; __p != __end_; ++__p)
+        *__p /= __x;
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator%=(const value_type& __x)
+{
+    for (value_type* __p = __begin_; __p != __end_; ++__p)
+        *__p %= __x;
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator+=(const value_type& __x)
+{
+    for (value_type* __p = __begin_; __p != __end_; ++__p)
+        *__p += __x;
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator-=(const value_type& __x)
+{
+    for (value_type* __p = __begin_; __p != __end_; ++__p)
+        *__p -= __x;
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator^=(const value_type& __x)
+{
+    for (value_type* __p = __begin_; __p != __end_; ++__p)
+        *__p ^= __x;
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator&=(const value_type& __x)
+{
+    for (value_type* __p = __begin_; __p != __end_; ++__p)
+        *__p &= __x;
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator|=(const value_type& __x)
+{
+    for (value_type* __p = __begin_; __p != __end_; ++__p)
+        *__p |= __x;
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator<<=(const value_type& __x)
+{
+    for (value_type* __p = __begin_; __p != __end_; ++__p)
+        *__p <<= __x;
+    return *this;
+}
+
+template <class _Tp>
+inline
+valarray<_Tp>&
+valarray<_Tp>::operator>>=(const value_type& __x)
+{
+    for (value_type* __p = __begin_; __p != __end_; ++__p)
+        *__p >>= __x;
+    return *this;
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    valarray<_Tp>&
+>::type
+valarray<_Tp>::operator*=(const _Expr& __v)
+{
+    size_t __i = 0;
+    for (value_type* __t = __begin_; __t != __end_ ; ++__t, ++__i)
+        *__t *= __v[__i];
+    return *this;
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    valarray<_Tp>&
+>::type
+valarray<_Tp>::operator/=(const _Expr& __v)
+{
+    size_t __i = 0;
+    for (value_type* __t = __begin_; __t != __end_ ; ++__t, ++__i)
+        *__t /= __v[__i];
+    return *this;
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    valarray<_Tp>&
+>::type
+valarray<_Tp>::operator%=(const _Expr& __v)
+{
+    size_t __i = 0;
+    for (value_type* __t = __begin_; __t != __end_ ; ++__t, ++__i)
+        *__t %= __v[__i];
+    return *this;
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    valarray<_Tp>&
+>::type
+valarray<_Tp>::operator+=(const _Expr& __v)
+{
+    size_t __i = 0;
+    for (value_type* __t = __begin_; __t != __end_ ; ++__t, ++__i)
+        *__t += __v[__i];
+    return *this;
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    valarray<_Tp>&
+>::type
+valarray<_Tp>::operator-=(const _Expr& __v)
+{
+    size_t __i = 0;
+    for (value_type* __t = __begin_; __t != __end_ ; ++__t, ++__i)
+        *__t -= __v[__i];
+    return *this;
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    valarray<_Tp>&
+>::type
+valarray<_Tp>::operator^=(const _Expr& __v)
+{
+    size_t __i = 0;
+    for (value_type* __t = __begin_; __t != __end_ ; ++__t, ++__i)
+        *__t ^= __v[__i];
+    return *this;
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    valarray<_Tp>&
+>::type
+valarray<_Tp>::operator|=(const _Expr& __v)
+{
+    size_t __i = 0;
+    for (value_type* __t = __begin_; __t != __end_ ; ++__t, ++__i)
+        *__t |= __v[__i];
+    return *this;
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    valarray<_Tp>&
+>::type
+valarray<_Tp>::operator&=(const _Expr& __v)
+{
+    size_t __i = 0;
+    for (value_type* __t = __begin_; __t != __end_ ; ++__t, ++__i)
+        *__t &= __v[__i];
+    return *this;
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    valarray<_Tp>&
+>::type
+valarray<_Tp>::operator<<=(const _Expr& __v)
+{
+    size_t __i = 0;
+    for (value_type* __t = __begin_; __t != __end_ ; ++__t, ++__i)
+        *__t <<= __v[__i];
+    return *this;
+}
+
+template <class _Tp>
+template <class _Expr>
+inline
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    valarray<_Tp>&
+>::type
+valarray<_Tp>::operator>>=(const _Expr& __v)
+{
+    size_t __i = 0;
+    for (value_type* __t = __begin_; __t != __end_ ; ++__t, ++__i)
+        *__t >>= __v[__i];
+    return *this;
+}
+
+template <class _Tp>
+inline
+void
+valarray<_Tp>::swap(valarray& __v) _NOEXCEPT
+{
+    _VSTD::swap(__begin_, __v.__begin_);
+    _VSTD::swap(__end_, __v.__end_);
+}
+
+template <class _Tp>
+inline
+_Tp
+valarray<_Tp>::sum() const
+{
+    if (__begin_ == __end_)
+        return value_type();
+    const value_type* __p = __begin_;
+    _Tp __r = *__p;
+    for (++__p; __p != __end_; ++__p)
+        __r += *__p;
+    return __r;
+}
+
+template <class _Tp>
+inline
+_Tp
+valarray<_Tp>::min() const
+{
+    if (__begin_ == __end_)
+        return value_type();
+    return *_VSTD::min_element(__begin_, __end_);
+}
+
+template <class _Tp>
+inline
+_Tp
+valarray<_Tp>::max() const
+{
+    if (__begin_ == __end_)
+        return value_type();
+    return *_VSTD::max_element(__begin_, __end_);
+}
+
+template <class _Tp>
+valarray<_Tp>
+valarray<_Tp>::shift(int __i) const
+{
+    valarray<value_type> __r;
+    size_t __n = size();
+    if (__n)
+    {
+        __r.__begin_ = __r.__end_ = allocator<value_type>().allocate(__n);
+        const value_type* __sb;
+        value_type* __tb;
+        value_type* __te;
+        if (__i >= 0)
+        {
+            __i = _VSTD::min(__i, static_cast<int>(__n));
+            __sb = __begin_ + __i;
+            __tb = __r.__begin_;
+            __te = __r.__begin_ + (__n - __i);
+        }
+        else
+        {
+            __i = _VSTD::min(-__i, static_cast<int>(__n));
+            __sb = __begin_;
+            __tb = __r.__begin_ + __i;
+            __te = __r.__begin_ + __n;
+        }
+        for (; __r.__end_ != __tb; ++__r.__end_)
+            ::new ((void*)__r.__end_) value_type();
+        for (; __r.__end_ != __te; ++__r.__end_, ++__sb)
+            ::new ((void*)__r.__end_) value_type(*__sb);
+        for (__te = __r.__begin_ + __n; __r.__end_ != __te; ++__r.__end_)
+            ::new ((void*)__r.__end_) value_type();
+    }
+    return __r;
+}
+
+template <class _Tp>
+valarray<_Tp>
+valarray<_Tp>::cshift(int __i) const
+{
+    valarray<value_type> __r;
+    size_t __n = size();
+    if (__n)
+    {
+        __r.__begin_ = __r.__end_ = allocator<value_type>().allocate(__n);
+        __i %= static_cast<int>(__n);
+        const value_type* __m = __i >= 0 ? __begin_ + __i : __end_ + __i;
+        for (const value_type* __s = __m; __s != __end_; ++__r.__end_, ++__s)
+            ::new ((void*)__r.__end_) value_type(*__s);
+        for (const value_type* __s = __begin_; __s != __m; ++__r.__end_, ++__s)
+            ::new ((void*)__r.__end_) value_type(*__s);
+    }
+    return __r;
+}
+
+template <class _Tp>
+valarray<_Tp>
+valarray<_Tp>::apply(value_type __f(value_type)) const
+{
+    valarray<value_type> __r;
+    size_t __n = size();
+    if (__n)
+    {
+        __r.__begin_ = __r.__end_ = allocator<value_type>().allocate(__n);
+        for (const value_type* __p = __begin_; __n; ++__r.__end_, ++__p, --__n)
+            ::new ((void*)__r.__end_) value_type(__f(*__p));
+    }
+    return __r;
+}
+
+template <class _Tp>
+valarray<_Tp>
+valarray<_Tp>::apply(value_type __f(const value_type&)) const
+{
+    valarray<value_type> __r;
+    size_t __n = size();
+    if (__n)
+    {
+        __r.__begin_ = __r.__end_ = allocator<value_type>().allocate(__n);
+        for (const value_type* __p = __begin_; __n; ++__r.__end_, ++__p, --__n)
+            ::new ((void*)__r.__end_) value_type(__f(*__p));
+    }
+    return __r;
+}
+
+template <class _Tp>
+inline
+void valarray<_Tp>::__clear(size_t __capacity)
+{
+  if (__begin_ != nullptr)
+  {
+    while (__end_ != __begin_)
+      (--__end_)->~value_type();
+    allocator<value_type>().deallocate(__begin_, __capacity);
+    __begin_ = __end_ = nullptr;
+  }
+}
+
+template <class _Tp>
+void
+valarray<_Tp>::resize(size_t __n, value_type __x)
+{
+    __clear(size());
+    if (__n)
+    {
+        __begin_ = __end_ = allocator<value_type>().allocate(__n);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            for (size_t __n_left = __n; __n_left; --__n_left, ++__end_)
+                ::new ((void*)__end_) value_type(__x);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __clear(__n);
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+}
+
+template<class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(valarray<_Tp>& __x, valarray<_Tp>& __y) _NOEXCEPT
+{
+    __x.swap(__y);
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<multiplies<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator*(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<multiplies<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(multiplies<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<multiplies<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator*(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<multiplies<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(multiplies<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<multiplies<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator*(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<multiplies<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(multiplies<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<divides<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator/(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<divides<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(divides<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<divides<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator/(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<divides<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(divides<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<divides<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator/(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<divides<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(divides<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<modulus<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator%(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<modulus<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(modulus<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<modulus<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator%(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<modulus<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(modulus<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<modulus<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator%(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<modulus<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(modulus<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<plus<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator+(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<plus<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(plus<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<plus<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator+(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<plus<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(plus<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<plus<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator+(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<plus<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(plus<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<minus<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator-(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<minus<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(minus<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<minus<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator-(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<minus<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(minus<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<minus<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator-(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<minus<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(minus<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<bit_xor<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator^(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<bit_xor<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(bit_xor<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<bit_xor<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator^(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<bit_xor<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(bit_xor<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<bit_xor<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator^(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<bit_xor<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(bit_xor<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<bit_and<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator&(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<bit_and<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(bit_and<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<bit_and<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator&(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<bit_and<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(bit_and<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<bit_and<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator&(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<bit_and<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(bit_and<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<bit_or<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator|(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<bit_or<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(bit_or<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<bit_or<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator|(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<bit_or<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(bit_or<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<bit_or<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator|(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<bit_or<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(bit_or<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<__bit_shift_left<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator<<(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<__bit_shift_left<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(__bit_shift_left<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<__bit_shift_left<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator<<(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<__bit_shift_left<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(__bit_shift_left<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<__bit_shift_left<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator<<(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<__bit_shift_left<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__bit_shift_left<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<__bit_shift_right<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator>>(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<__bit_shift_right<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(__bit_shift_right<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<__bit_shift_right<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator>>(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<__bit_shift_right<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(__bit_shift_right<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<__bit_shift_right<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator>>(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<__bit_shift_right<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__bit_shift_right<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<logical_and<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator&&(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<logical_and<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(logical_and<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<logical_and<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator&&(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<logical_and<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(logical_and<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<logical_and<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator&&(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<logical_and<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(logical_and<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<logical_or<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator||(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<logical_or<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(logical_or<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<logical_or<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator||(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<logical_or<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(logical_or<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<logical_or<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator||(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<logical_or<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(logical_or<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<equal_to<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator==(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<equal_to<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(equal_to<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<equal_to<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator==(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<equal_to<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(equal_to<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<equal_to<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator==(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<equal_to<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(equal_to<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<not_equal_to<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator!=(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<not_equal_to<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(not_equal_to<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<not_equal_to<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator!=(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<not_equal_to<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(not_equal_to<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<not_equal_to<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator!=(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<not_equal_to<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(not_equal_to<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<less<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator<(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<less<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(less<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<less<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator<(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<less<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(less<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<less<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator<(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<less<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(less<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<greater<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator>(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<greater<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(greater<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<greater<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator>(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<greater<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(greater<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<greater<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator>(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<greater<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(greater<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<less_equal<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator<=(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<less_equal<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(less_equal<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<less_equal<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator<=(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<less_equal<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(less_equal<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<less_equal<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator<=(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<less_equal<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(less_equal<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<greater_equal<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+operator>=(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<greater_equal<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(greater_equal<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<greater_equal<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+operator>=(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<greater_equal<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(greater_equal<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<greater_equal<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+operator>=(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<greater_equal<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(greater_equal<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__abs_expr<typename _Expr::value_type>, _Expr> >
+>::type
+abs(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__abs_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__abs_expr<value_type>(), __x));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__acos_expr<typename _Expr::value_type>, _Expr> >
+>::type
+acos(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__acos_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__acos_expr<value_type>(), __x));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__asin_expr<typename _Expr::value_type>, _Expr> >
+>::type
+asin(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__asin_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__asin_expr<value_type>(), __x));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__atan_expr<typename _Expr::value_type>, _Expr> >
+>::type
+atan(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__atan_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__atan_expr<value_type>(), __x));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<__atan2_expr<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+atan2(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<__atan2_expr<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(__atan2_expr<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<__atan2_expr<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+atan2(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<__atan2_expr<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(__atan2_expr<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<__atan2_expr<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+atan2(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<__atan2_expr<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__atan2_expr<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__cos_expr<typename _Expr::value_type>, _Expr> >
+>::type
+cos(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__cos_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__cos_expr<value_type>(), __x));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__cosh_expr<typename _Expr::value_type>, _Expr> >
+>::type
+cosh(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__cosh_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__cosh_expr<value_type>(), __x));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__exp_expr<typename _Expr::value_type>, _Expr> >
+>::type
+exp(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__exp_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__exp_expr<value_type>(), __x));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__log_expr<typename _Expr::value_type>, _Expr> >
+>::type
+log(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__log_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__log_expr<value_type>(), __x));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__log10_expr<typename _Expr::value_type>, _Expr> >
+>::type
+log10(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__log10_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__log10_expr<value_type>(), __x));
+}
+
+template<class _Expr1, class _Expr2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr1>::value && __is_val_expr<_Expr2>::value,
+    __val_expr<_BinaryOp<__pow_expr<typename _Expr1::value_type>, _Expr1, _Expr2> >
+>::type
+pow(const _Expr1& __x, const _Expr2& __y)
+{
+    typedef typename _Expr1::value_type value_type;
+    typedef _BinaryOp<__pow_expr<value_type>, _Expr1, _Expr2> _Op;
+    return __val_expr<_Op>(_Op(__pow_expr<value_type>(), __x, __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<__pow_expr<typename _Expr::value_type>,
+               _Expr, __scalar_expr<typename _Expr::value_type> > >
+>::type
+pow(const _Expr& __x, const typename _Expr::value_type& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<__pow_expr<value_type>, _Expr, __scalar_expr<value_type> > _Op;
+    return __val_expr<_Op>(_Op(__pow_expr<value_type>(),
+                           __x, __scalar_expr<value_type>(__y, __x.size())));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_BinaryOp<__pow_expr<typename _Expr::value_type>,
+               __scalar_expr<typename _Expr::value_type>, _Expr> >
+>::type
+pow(const typename _Expr::value_type& __x, const _Expr& __y)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _BinaryOp<__pow_expr<value_type>, __scalar_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__pow_expr<value_type>(),
+                           __scalar_expr<value_type>(__x, __y.size()), __y));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__sin_expr<typename _Expr::value_type>, _Expr> >
+>::type
+sin(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__sin_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__sin_expr<value_type>(), __x));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__sinh_expr<typename _Expr::value_type>, _Expr> >
+>::type
+sinh(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__sinh_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__sinh_expr<value_type>(), __x));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__sqrt_expr<typename _Expr::value_type>, _Expr> >
+>::type
+sqrt(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__sqrt_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__sqrt_expr<value_type>(), __x));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__tan_expr<typename _Expr::value_type>, _Expr> >
+>::type
+tan(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__tan_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__tan_expr<value_type>(), __x));
+}
+
+template<class _Expr>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if
+<
+    __is_val_expr<_Expr>::value,
+    __val_expr<_UnaryOp<__tanh_expr<typename _Expr::value_type>, _Expr> >
+>::type
+tanh(const _Expr& __x)
+{
+    typedef typename _Expr::value_type value_type;
+    typedef _UnaryOp<__tanh_expr<value_type>, _Expr> _Op;
+    return __val_expr<_Op>(_Op(__tanh_expr<value_type>(), __x));
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp*
+begin(valarray<_Tp>& __v)
+{
+    return __v.__begin_;
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+const _Tp*
+begin(const valarray<_Tp>& __v)
+{
+    return __v.__begin_;
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+_Tp*
+end(valarray<_Tp>& __v)
+{
+    return __v.__end_;
+}
+
+template <class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY
+const _Tp*
+end(const valarray<_Tp>& __v)
+{
+    return __v.__end_;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_VALARRAY
diff --git a/contrib/libs/cxxsupp/libcxx/include/variant b/contrib/libs/cxxsupp/libcxx/include/variant
new file mode 100644
index 00000000000..972c18a8113
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/variant
@@ -0,0 +1,1778 @@
+// -*- C++ -*-
+//===------------------------------ variant -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_VARIANT
+#define _LIBCPP_VARIANT
+
+/*
+   variant synopsis
+
+namespace std {
+
+  // 20.7.2, class template variant
+  template <class... Types>
+  class variant {
+  public:
+
+    // 20.7.2.1, constructors
+    constexpr variant() noexcept(see below);
+    variant(const variant&);                // constexpr in C++20
+    variant(variant&&) noexcept(see below); // constexpr in C++20
+
+    template <class T> constexpr variant(T&&) noexcept(see below);
+
+    template <class T, class... Args>
+    constexpr explicit variant(in_place_type_t<T>, Args&&...);
+
+    template <class T, class U, class... Args>
+    constexpr explicit variant(
+        in_place_type_t<T>, initializer_list<U>, Args&&...);
+
+    template <size_t I, class... Args>
+    constexpr explicit variant(in_place_index_t<I>, Args&&...);
+
+    template <size_t I, class U, class... Args>
+    constexpr explicit variant(
+        in_place_index_t<I>, initializer_list<U>, Args&&...);
+
+    // 20.7.2.2, destructor
+    ~variant();
+
+    // 20.7.2.3, assignment
+    variant& operator=(const variant&);                // constexpr in C++20
+    variant& operator=(variant&&) noexcept(see below); // constexpr in C++20
+
+    template <class T> variant& operator=(T&&) noexcept(see below);
+
+    // 20.7.2.4, modifiers
+    template <class T, class... Args>
+    T& emplace(Args&&...);
+
+    template <class T, class U, class... Args>
+    T& emplace(initializer_list<U>, Args&&...);
+
+    template <size_t I, class... Args>
+    variant_alternative_t<I, variant>& emplace(Args&&...);
+
+    template <size_t I, class U, class...  Args>
+    variant_alternative_t<I, variant>& emplace(initializer_list<U>, Args&&...);
+
+    // 20.7.2.5, value status
+    constexpr bool valueless_by_exception() const noexcept;
+    constexpr size_t index() const noexcept;
+
+    // 20.7.2.6, swap
+    void swap(variant&) noexcept(see below);
+  };
+
+  // 20.7.3, variant helper classes
+  template <class T> struct variant_size; // undefined
+
+  template <class T>
+  inline constexpr size_t variant_size_v = variant_size<T>::value;
+
+  template <class T> struct variant_size<const T>;
+  template <class T> struct variant_size<volatile T>;
+  template <class T> struct variant_size<const volatile T>;
+
+  template <class... Types>
+  struct variant_size<variant<Types...>>;
+
+  template <size_t I, class T> struct variant_alternative; // undefined
+
+  template <size_t I, class T>
+  using variant_alternative_t = typename variant_alternative<I, T>::type;
+
+  template <size_t I, class T> struct variant_alternative<I, const T>;
+  template <size_t I, class T> struct variant_alternative<I, volatile T>;
+  template <size_t I, class T> struct variant_alternative<I, const volatile T>;
+
+  template <size_t I, class... Types>
+  struct variant_alternative<I, variant<Types...>>;
+
+  inline constexpr size_t variant_npos = -1;
+
+  // 20.7.4, value access
+  template <class T, class... Types>
+  constexpr bool holds_alternative(const variant<Types...>&) noexcept;
+
+  template <size_t I, class... Types>
+  constexpr variant_alternative_t<I, variant<Types...>>&
+  get(variant<Types...>&);
+
+  template <size_t I, class... Types>
+  constexpr variant_alternative_t<I, variant<Types...>>&&
+  get(variant<Types...>&&);
+
+  template <size_t I, class... Types>
+  constexpr variant_alternative_t<I, variant<Types...>> const&
+  get(const variant<Types...>&);
+
+  template <size_t I, class... Types>
+  constexpr variant_alternative_t<I, variant<Types...>> const&&
+  get(const variant<Types...>&&);
+
+  template <class T, class...  Types>
+  constexpr T& get(variant<Types...>&);
+
+  template <class T, class... Types>
+  constexpr T&& get(variant<Types...>&&);
+
+  template <class T, class... Types>
+  constexpr const T& get(const variant<Types...>&);
+
+  template <class T, class... Types>
+  constexpr const T&& get(const variant<Types...>&&);
+
+  template <size_t I, class... Types>
+  constexpr add_pointer_t<variant_alternative_t<I, variant<Types...>>>
+  get_if(variant<Types...>*) noexcept;
+
+  template <size_t I, class... Types>
+  constexpr add_pointer_t<const variant_alternative_t<I, variant<Types...>>>
+  get_if(const variant<Types...>*) noexcept;
+
+  template <class T, class... Types>
+  constexpr add_pointer_t<T>
+  get_if(variant<Types...>*) noexcept;
+
+  template <class T, class... Types>
+  constexpr add_pointer_t<const T>
+  get_if(const variant<Types...>*) noexcept;
+
+  // 20.7.5, relational operators
+  template <class... Types>
+  constexpr bool operator==(const variant<Types...>&, const variant<Types...>&);
+
+  template <class... Types>
+  constexpr bool operator!=(const variant<Types...>&, const variant<Types...>&);
+
+  template <class... Types>
+  constexpr bool operator<(const variant<Types...>&, const variant<Types...>&);
+
+  template <class... Types>
+  constexpr bool operator>(const variant<Types...>&, const variant<Types...>&);
+
+  template <class... Types>
+  constexpr bool operator<=(const variant<Types...>&, const variant<Types...>&);
+
+  template <class... Types>
+  constexpr bool operator>=(const variant<Types...>&, const variant<Types...>&);
+
+  // 20.7.6, visitation
+  template <class Visitor, class... Variants>
+  constexpr see below visit(Visitor&&, Variants&&...);
+
+  template <class R, class Visitor, class... Variants>
+  constexpr R visit(Visitor&&, Variants&&...); // since C++20
+
+  // 20.7.7, class monostate
+  struct monostate;
+
+  // 20.7.8, monostate relational operators
+  constexpr bool operator<(monostate, monostate) noexcept;
+  constexpr bool operator>(monostate, monostate) noexcept;
+  constexpr bool operator<=(monostate, monostate) noexcept;
+  constexpr bool operator>=(monostate, monostate) noexcept;
+  constexpr bool operator==(monostate, monostate) noexcept;
+  constexpr bool operator!=(monostate, monostate) noexcept;
+
+  // 20.7.9, specialized algorithms
+  template <class... Types>
+  void swap(variant<Types...>&, variant<Types...>&) noexcept(see below);
+
+  // 20.7.10, class bad_variant_access
+  class bad_variant_access;
+
+  // 20.7.11, hash support
+  template <class T> struct hash;
+  template <class... Types> struct hash<variant<Types...>>;
+  template <> struct hash<monostate>;
+
+} // namespace std
+
+*/
+
+#include <__availability>
+#include <__config>
+#include <__functional/hash.h>
+#include <__tuple>
+#include <__utility/forward.h>
+#include <__variant/monostate.h>
+#include <compare>
+#include <exception>
+#include <initializer_list>
+#include <limits>
+#include <new>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+namespace std { // explicitly not using versioning namespace
+
+class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS bad_variant_access : public exception {
+public:
+  virtual const char* what() const _NOEXCEPT;
+};
+
+} // namespace std
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 14
+
+// Light N-dimensional array of function pointers. Used in place of std::array to avoid
+// adding a dependency.
+template<class _Tp, size_t _Size>
+struct __farray {
+  static_assert(_Size > 0, "N-dimensional array should never be empty in std::visit");
+  _Tp __buf_[_Size] = {};
+
+  _LIBCPP_INLINE_VISIBILITY constexpr
+  const _Tp &operator[](size_t __n) const noexcept {
+      return __buf_[__n];
+  }
+};
+
+_LIBCPP_NORETURN
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
+void __throw_bad_variant_access() {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        throw bad_variant_access();
+#else
+        _VSTD::abort();
+#endif
+}
+
+template <class... _Types>
+class _LIBCPP_TEMPLATE_VIS variant;
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS variant_size;
+
+template <class _Tp>
+inline constexpr size_t variant_size_v = variant_size<_Tp>::value;
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS variant_size<const _Tp> : variant_size<_Tp> {};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS variant_size<volatile _Tp> : variant_size<_Tp> {};
+
+template <class _Tp>
+struct _LIBCPP_TEMPLATE_VIS variant_size<const volatile _Tp>
+    : variant_size<_Tp> {};
+
+template <class... _Types>
+struct _LIBCPP_TEMPLATE_VIS variant_size<variant<_Types...>>
+    : integral_constant<size_t, sizeof...(_Types)> {};
+
+template <size_t _Ip, class _Tp>
+struct _LIBCPP_TEMPLATE_VIS variant_alternative;
+
+template <size_t _Ip, class _Tp>
+using variant_alternative_t = typename variant_alternative<_Ip, _Tp>::type;
+
+template <size_t _Ip, class _Tp>
+struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const _Tp>
+    : add_const<variant_alternative_t<_Ip, _Tp>> {};
+
+template <size_t _Ip, class _Tp>
+struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, volatile _Tp>
+    : add_volatile<variant_alternative_t<_Ip, _Tp>> {};
+
+template <size_t _Ip, class _Tp>
+struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const volatile _Tp>
+    : add_cv<variant_alternative_t<_Ip, _Tp>> {};
+
+template <size_t _Ip, class... _Types>
+struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, variant<_Types...>> {
+  static_assert(_Ip < sizeof...(_Types), "Index out of bounds in std::variant_alternative<>");
+  using type = __type_pack_element<_Ip, _Types...>;
+};
+
+inline constexpr size_t variant_npos = static_cast<size_t>(-1);
+
+constexpr int __choose_index_type(unsigned int __num_elem) {
+  if (__num_elem < numeric_limits<unsigned char>::max())
+    return 0;
+  if (__num_elem < numeric_limits<unsigned short>::max())
+    return 1;
+  return 2;
+}
+
+template <size_t _NumAlts>
+using __variant_index_t =
+#ifndef _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION
+  unsigned int;
+#else
+  std::tuple_element_t<
+      __choose_index_type(_NumAlts),
+      std::tuple<unsigned char, unsigned short, unsigned int>
+  >;
+#endif
+
+template <class _IndexType>
+constexpr _IndexType __variant_npos = static_cast<_IndexType>(-1);
+
+template <class... _Types>
+class _LIBCPP_TEMPLATE_VIS variant;
+
+template <class... _Types>
+_LIBCPP_INLINE_VISIBILITY constexpr variant<_Types...>&
+__as_variant(variant<_Types...>& __vs) noexcept {
+  return __vs;
+}
+
+template <class... _Types>
+_LIBCPP_INLINE_VISIBILITY constexpr const variant<_Types...>&
+__as_variant(const variant<_Types...>& __vs) noexcept {
+  return __vs;
+}
+
+template <class... _Types>
+_LIBCPP_INLINE_VISIBILITY constexpr variant<_Types...>&&
+__as_variant(variant<_Types...>&& __vs) noexcept {
+  return _VSTD::move(__vs);
+}
+
+template <class... _Types>
+_LIBCPP_INLINE_VISIBILITY constexpr const variant<_Types...>&&
+__as_variant(const variant<_Types...>&& __vs) noexcept {
+  return _VSTD::move(__vs);
+}
+
+namespace __find_detail {
+
+template <class _Tp, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr size_t __find_index() {
+  constexpr bool __matches[] = {is_same_v<_Tp, _Types>...};
+  size_t __result = __not_found;
+  for (size_t __i = 0; __i < sizeof...(_Types); ++__i) {
+    if (__matches[__i]) {
+      if (__result != __not_found) {
+        return __ambiguous;
+      }
+      __result = __i;
+    }
+  }
+  return __result;
+}
+
+template <size_t _Index>
+struct __find_unambiguous_index_sfinae_impl
+    : integral_constant<size_t, _Index> {};
+
+template <>
+struct __find_unambiguous_index_sfinae_impl<__not_found> {};
+
+template <>
+struct __find_unambiguous_index_sfinae_impl<__ambiguous> {};
+
+template <class _Tp, class... _Types>
+struct __find_unambiguous_index_sfinae
+    : __find_unambiguous_index_sfinae_impl<__find_index<_Tp, _Types...>()> {};
+
+} // namespace __find_detail
+
+namespace __variant_detail {
+
+struct __valueless_t {};
+
+enum class _Trait { _TriviallyAvailable, _Available, _Unavailable };
+
+template <typename _Tp,
+          template <typename> class _IsTriviallyAvailable,
+          template <typename> class _IsAvailable>
+constexpr _Trait __trait =
+    _IsTriviallyAvailable<_Tp>::value
+        ? _Trait::_TriviallyAvailable
+        : _IsAvailable<_Tp>::value ? _Trait::_Available : _Trait::_Unavailable;
+
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr _Trait __common_trait(initializer_list<_Trait> __traits) {
+  _Trait __result = _Trait::_TriviallyAvailable;
+  for (_Trait __t : __traits) {
+    if (static_cast<int>(__t) > static_cast<int>(__result)) {
+      __result = __t;
+    }
+  }
+  return __result;
+}
+
+template <typename... _Types>
+struct __traits {
+  static constexpr _Trait __copy_constructible_trait =
+      __common_trait({__trait<_Types,
+                              is_trivially_copy_constructible,
+                              is_copy_constructible>...});
+
+  static constexpr _Trait __move_constructible_trait =
+      __common_trait({__trait<_Types,
+                              is_trivially_move_constructible,
+                              is_move_constructible>...});
+
+  static constexpr _Trait __copy_assignable_trait = __common_trait(
+      {__copy_constructible_trait,
+       __trait<_Types, is_trivially_copy_assignable, is_copy_assignable>...});
+
+  static constexpr _Trait __move_assignable_trait = __common_trait(
+      {__move_constructible_trait,
+       __trait<_Types, is_trivially_move_assignable, is_move_assignable>...});
+
+  static constexpr _Trait __destructible_trait = __common_trait(
+      {__trait<_Types, is_trivially_destructible, is_destructible>...});
+};
+
+namespace __access {
+
+struct __union {
+  template <class _Vp>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<0>) {
+    return _VSTD::forward<_Vp>(__v).__head;
+  }
+
+  template <class _Vp, size_t _Ip>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<_Ip>) {
+    return __get_alt(_VSTD::forward<_Vp>(__v).__tail, in_place_index<_Ip - 1>);
+  }
+};
+
+struct __base {
+  template <size_t _Ip, class _Vp>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto&& __get_alt(_Vp&& __v) {
+    return __union::__get_alt(_VSTD::forward<_Vp>(__v).__data,
+                              in_place_index<_Ip>);
+  }
+};
+
+struct __variant {
+  template <size_t _Ip, class _Vp>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto&& __get_alt(_Vp&& __v) {
+    return __base::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v).__impl);
+  }
+};
+
+} // namespace __access
+
+namespace __visitation {
+
+struct __base {
+  template <class _Visitor, class... _Vs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr decltype(auto)
+  __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
+    constexpr auto __fdiagonal =
+        __make_fdiagonal<_Visitor&&,
+                         decltype(_VSTD::forward<_Vs>(__vs).__as_base())...>();
+    return __fdiagonal[__index](_VSTD::forward<_Visitor>(__visitor),
+                                _VSTD::forward<_Vs>(__vs).__as_base()...);
+  }
+
+  template <class _Visitor, class... _Vs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor,
+                                              _Vs&&... __vs) {
+    constexpr auto __fmatrix =
+        __make_fmatrix<_Visitor&&,
+                       decltype(_VSTD::forward<_Vs>(__vs).__as_base())...>();
+    return __at(__fmatrix, __vs.index()...)(
+        _VSTD::forward<_Visitor>(__visitor),
+        _VSTD::forward<_Vs>(__vs).__as_base()...);
+  }
+
+private:
+  template <class _Tp>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr const _Tp& __at(const _Tp& __elem) { return __elem; }
+
+  template <class _Tp, size_t _Np, typename... _Indices>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto&& __at(const __farray<_Tp, _Np>& __elems,
+                               size_t __index, _Indices... __indices) {
+    return __at(__elems[__index], __indices...);
+  }
+
+  template <class _Fp, class... _Fs>
+  static constexpr void __std_visit_visitor_return_type_check() {
+    static_assert(
+        __all<is_same_v<_Fp, _Fs>...>::value,
+        "`std::visit` requires the visitor to have a single return type.");
+  }
+
+  template <class... _Fs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_farray(_Fs&&... __fs) {
+    __std_visit_visitor_return_type_check<__uncvref_t<_Fs>...>();
+    using __result = __farray<common_type_t<__uncvref_t<_Fs>...>, sizeof...(_Fs)>;
+    return __result{{_VSTD::forward<_Fs>(__fs)...}};
+  }
+
+  template <size_t... _Is>
+  struct __dispatcher {
+    template <class _Fp, class... _Vs>
+    inline _LIBCPP_INLINE_VISIBILITY
+    static constexpr decltype(auto) __dispatch(_Fp __f, _Vs... __vs) {
+        return _VSTD::__invoke_constexpr(
+            static_cast<_Fp>(__f),
+            __access::__base::__get_alt<_Is>(static_cast<_Vs>(__vs))...);
+    }
+  };
+
+  template <class _Fp, class... _Vs, size_t... _Is>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_dispatch(index_sequence<_Is...>) {
+    return __dispatcher<_Is...>::template __dispatch<_Fp, _Vs...>;
+  }
+
+  template <size_t _Ip, class _Fp, class... _Vs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_fdiagonal_impl() {
+    return __make_dispatch<_Fp, _Vs...>(
+        index_sequence<((void)__identity<_Vs>{}, _Ip)...>{});
+  }
+
+  template <class _Fp, class... _Vs, size_t... _Is>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_fdiagonal_impl(index_sequence<_Is...>) {
+    return __base::__make_farray(__make_fdiagonal_impl<_Is, _Fp, _Vs...>()...);
+  }
+
+  template <class _Fp, class _Vp, class... _Vs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_fdiagonal() {
+    constexpr size_t _Np = __uncvref_t<_Vp>::__size();
+    static_assert(__all<(_Np == __uncvref_t<_Vs>::__size())...>::value);
+    return __make_fdiagonal_impl<_Fp, _Vp, _Vs...>(make_index_sequence<_Np>{});
+  }
+
+  template <class _Fp, class... _Vs, size_t... _Is>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_fmatrix_impl(index_sequence<_Is...> __is) {
+    return __make_dispatch<_Fp, _Vs...>(__is);
+  }
+
+  template <class _Fp, class... _Vs, size_t... _Is, size_t... _Js, class... _Ls>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_fmatrix_impl(index_sequence<_Is...>,
+                                            index_sequence<_Js...>,
+                                            _Ls... __ls) {
+    return __base::__make_farray(__make_fmatrix_impl<_Fp, _Vs...>(
+        index_sequence<_Is..., _Js>{}, __ls...)...);
+  }
+
+  template <class _Fp, class... _Vs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_fmatrix() {
+    return __make_fmatrix_impl<_Fp, _Vs...>(
+        index_sequence<>{}, make_index_sequence<__uncvref_t<_Vs>::__size()>{}...);
+  }
+};
+
+struct __variant {
+  template <class _Visitor, class... _Vs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr decltype(auto)
+  __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
+    return __base::__visit_alt_at(__index,
+                                  _VSTD::forward<_Visitor>(__visitor),
+                                  _VSTD::forward<_Vs>(__vs).__impl...);
+  }
+
+  template <class _Visitor, class... _Vs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor,
+                                              _Vs&&... __vs) {
+    return __base::__visit_alt(
+        _VSTD::forward<_Visitor>(__visitor),
+        _VSTD::__as_variant(_VSTD::forward<_Vs>(__vs)).__impl...);
+  }
+
+  template <class _Visitor, class... _Vs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr decltype(auto)
+  __visit_value_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
+    return __visit_alt_at(
+        __index,
+        __make_value_visitor(_VSTD::forward<_Visitor>(__visitor)),
+        _VSTD::forward<_Vs>(__vs)...);
+  }
+
+  template <class _Visitor, class... _Vs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr decltype(auto) __visit_value(_Visitor&& __visitor,
+                                                _Vs&&... __vs) {
+    return __visit_alt(
+        __make_value_visitor(_VSTD::forward<_Visitor>(__visitor)),
+        _VSTD::forward<_Vs>(__vs)...);
+  }
+
+#if _LIBCPP_STD_VER > 17
+  template <class _Rp, class _Visitor, class... _Vs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr _Rp __visit_value(_Visitor&& __visitor,
+                                     _Vs&&... __vs) {
+    return __visit_alt(
+        __make_value_visitor<_Rp>(_VSTD::forward<_Visitor>(__visitor)),
+        _VSTD::forward<_Vs>(__vs)...);
+  }
+#endif
+
+private:
+  template <class _Visitor, class... _Values>
+  static constexpr void __std_visit_exhaustive_visitor_check() {
+    static_assert(is_invocable_v<_Visitor, _Values...>,
+                  "`std::visit` requires the visitor to be exhaustive.");
+  }
+
+  template <class _Visitor>
+  struct __value_visitor {
+    template <class... _Alts>
+    inline _LIBCPP_INLINE_VISIBILITY
+    constexpr decltype(auto) operator()(_Alts&&... __alts) const {
+      __std_visit_exhaustive_visitor_check<
+          _Visitor,
+          decltype((_VSTD::forward<_Alts>(__alts).__value))...>();
+      return _VSTD::__invoke_constexpr(_VSTD::forward<_Visitor>(__visitor),
+                                _VSTD::forward<_Alts>(__alts).__value...);
+    }
+    _Visitor&& __visitor;
+  };
+
+#if _LIBCPP_STD_VER > 17
+  template <class _Rp, class _Visitor>
+  struct __value_visitor_return_type {
+    template <class... _Alts>
+    inline _LIBCPP_INLINE_VISIBILITY
+    constexpr _Rp operator()(_Alts&&... __alts) const {
+      __std_visit_exhaustive_visitor_check<
+          _Visitor,
+          decltype((_VSTD::forward<_Alts>(__alts).__value))...>();
+      if constexpr (is_void_v<_Rp>) {
+        _VSTD::__invoke_constexpr(_VSTD::forward<_Visitor>(__visitor),
+                                  _VSTD::forward<_Alts>(__alts).__value...);
+      }
+      else {
+        return _VSTD::__invoke_constexpr(_VSTD::forward<_Visitor>(__visitor),
+                                         _VSTD::forward<_Alts>(__alts).__value...);
+      }
+    }
+
+    _Visitor&& __visitor;
+  };
+#endif
+
+  template <class _Visitor>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_value_visitor(_Visitor&& __visitor) {
+    return __value_visitor<_Visitor>{_VSTD::forward<_Visitor>(__visitor)};
+  }
+
+#if _LIBCPP_STD_VER > 17
+  template <class _Rp, class _Visitor>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr auto __make_value_visitor(_Visitor&& __visitor) {
+    return __value_visitor_return_type<_Rp, _Visitor>{_VSTD::forward<_Visitor>(__visitor)};
+  }
+#endif
+};
+
+} // namespace __visitation
+
+template <size_t _Index, class _Tp>
+struct _LIBCPP_TEMPLATE_VIS __alt {
+  using __value_type = _Tp;
+
+  template <class... _Args>
+  inline _LIBCPP_INLINE_VISIBILITY
+  explicit constexpr __alt(in_place_t, _Args&&... __args)
+      : __value(_VSTD::forward<_Args>(__args)...) {}
+
+  __value_type __value;
+};
+
+template <_Trait _DestructibleTrait, size_t _Index, class... _Types>
+union _LIBCPP_TEMPLATE_VIS __union;
+
+template <_Trait _DestructibleTrait, size_t _Index>
+union _LIBCPP_TEMPLATE_VIS __union<_DestructibleTrait, _Index> {};
+
+#define _LIBCPP_VARIANT_UNION(destructible_trait, destructor)                  \
+  template <size_t _Index, class _Tp, class... _Types>                         \
+  union _LIBCPP_TEMPLATE_VIS __union<destructible_trait,                      \
+                                      _Index,                                  \
+                                      _Tp,                                     \
+                                      _Types...> {                             \
+  public:                                                                      \
+    inline _LIBCPP_INLINE_VISIBILITY                                           \
+    explicit constexpr __union(__valueless_t) noexcept : __dummy{} {}          \
+                                                                               \
+    template <class... _Args>                                                  \
+    inline _LIBCPP_INLINE_VISIBILITY                                           \
+    explicit constexpr __union(in_place_index_t<0>, _Args&&... __args)         \
+        : __head(in_place, _VSTD::forward<_Args>(__args)...) {}                \
+                                                                               \
+    template <size_t _Ip, class... _Args>                                      \
+    inline _LIBCPP_INLINE_VISIBILITY                                           \
+    explicit constexpr __union(in_place_index_t<_Ip>, _Args&&... __args)       \
+        : __tail(in_place_index<_Ip - 1>, _VSTD::forward<_Args>(__args)...) {} \
+                                                                               \
+    __union(const __union&) = default;                                         \
+    __union(__union&&) = default;                                              \
+                                                                               \
+    destructor                                                                 \
+                                                                               \
+    __union& operator=(const __union&) = default;                              \
+    __union& operator=(__union&&) = default;                                   \
+                                                                               \
+  private:                                                                     \
+    char __dummy;                                                              \
+    __alt<_Index, _Tp> __head;                                                 \
+    __union<destructible_trait, _Index + 1, _Types...> __tail;                 \
+                                                                               \
+    friend struct __access::__union;                                           \
+  }
+
+_LIBCPP_VARIANT_UNION(_Trait::_TriviallyAvailable, ~__union() = default;);
+_LIBCPP_VARIANT_UNION(_Trait::_Available, ~__union() {});
+_LIBCPP_VARIANT_UNION(_Trait::_Unavailable, ~__union() = delete;);
+
+#undef _LIBCPP_VARIANT_UNION
+
+template <_Trait _DestructibleTrait, class... _Types>
+class _LIBCPP_TEMPLATE_VIS __base {
+public:
+  using __index_t = __variant_index_t<sizeof...(_Types)>;
+
+  inline _LIBCPP_INLINE_VISIBILITY
+  explicit constexpr __base(__valueless_t tag) noexcept
+      : __data(tag), __index(__variant_npos<__index_t>) {}
+
+  template <size_t _Ip, class... _Args>
+  inline _LIBCPP_INLINE_VISIBILITY
+  explicit constexpr __base(in_place_index_t<_Ip>, _Args&&... __args)
+      :
+        __data(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...),
+        __index(_Ip) {}
+
+  inline _LIBCPP_INLINE_VISIBILITY
+  constexpr bool valueless_by_exception() const noexcept {
+    return index() == variant_npos;
+  }
+
+  inline _LIBCPP_INLINE_VISIBILITY
+  constexpr size_t index() const noexcept {
+    return __index == __variant_npos<__index_t> ? variant_npos : __index;
+  }
+
+protected:
+  inline _LIBCPP_INLINE_VISIBILITY
+  constexpr auto&& __as_base() & { return *this; }
+
+  inline _LIBCPP_INLINE_VISIBILITY
+  constexpr auto&& __as_base() && { return _VSTD::move(*this); }
+
+  inline _LIBCPP_INLINE_VISIBILITY
+  constexpr auto&& __as_base() const & { return *this; }
+
+  inline _LIBCPP_INLINE_VISIBILITY
+  constexpr auto&& __as_base() const && { return _VSTD::move(*this); }
+
+  inline _LIBCPP_INLINE_VISIBILITY
+  static constexpr size_t __size() { return sizeof...(_Types); }
+
+  __union<_DestructibleTrait, 0, _Types...> __data;
+  __index_t __index;
+
+  friend struct __access::__base;
+  friend struct __visitation::__base;
+};
+
+template <class _Traits, _Trait = _Traits::__destructible_trait>
+class _LIBCPP_TEMPLATE_VIS __dtor;
+
+#define _LIBCPP_VARIANT_DESTRUCTOR(destructible_trait, destructor, destroy)    \
+  template <class... _Types>                                                   \
+  class _LIBCPP_TEMPLATE_VIS __dtor<__traits<_Types...>,                       \
+                                    destructible_trait>                        \
+      : public __base<destructible_trait, _Types...> {                         \
+    using __base_type = __base<destructible_trait, _Types...>;                 \
+    using __index_t = typename __base_type::__index_t;                         \
+                                                                               \
+  public:                                                                      \
+    using __base_type::__base_type;                                            \
+    using __base_type::operator=;                                              \
+                                                                               \
+    __dtor(const __dtor&) = default;                                           \
+    __dtor(__dtor&&) = default;                                                \
+    destructor                                                                 \
+    __dtor& operator=(const __dtor&) = default;                                \
+    __dtor& operator=(__dtor&&) = default;                                     \
+                                                                               \
+  protected:                                                                   \
+    inline _LIBCPP_INLINE_VISIBILITY                                           \
+    destroy                                                                    \
+  }
+
+_LIBCPP_VARIANT_DESTRUCTOR(
+    _Trait::_TriviallyAvailable,
+    ~__dtor() = default;,
+    void __destroy() noexcept { this->__index = __variant_npos<__index_t>; });
+
+_LIBCPP_VARIANT_DESTRUCTOR(
+    _Trait::_Available,
+    ~__dtor() { __destroy(); },
+    void __destroy() noexcept {
+      if (!this->valueless_by_exception()) {
+        __visitation::__base::__visit_alt(
+            [](auto& __alt) noexcept {
+              using __alt_type = __uncvref_t<decltype(__alt)>;
+              __alt.~__alt_type();
+            },
+            *this);
+      }
+      this->__index = __variant_npos<__index_t>;
+    });
+
+_LIBCPP_VARIANT_DESTRUCTOR(
+    _Trait::_Unavailable,
+    ~__dtor() = delete;,
+    void __destroy() noexcept = delete;);
+
+#undef _LIBCPP_VARIANT_DESTRUCTOR
+
+template <class _Traits>
+class _LIBCPP_TEMPLATE_VIS __ctor : public __dtor<_Traits> {
+  using __base_type = __dtor<_Traits>;
+
+public:
+  using __base_type::__base_type;
+  using __base_type::operator=;
+
+protected:
+  template <size_t _Ip, class _Tp, class... _Args>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static _Tp& __construct_alt(__alt<_Ip, _Tp>& __a, _Args&&... __args) {
+    ::new ((void*)_VSTD::addressof(__a))
+        __alt<_Ip, _Tp>(in_place, _VSTD::forward<_Args>(__args)...);
+    return __a.__value;
+  }
+
+  template <class _Rhs>
+  inline _LIBCPP_INLINE_VISIBILITY
+  static void __generic_construct(__ctor& __lhs, _Rhs&& __rhs) {
+    __lhs.__destroy();
+    if (!__rhs.valueless_by_exception()) {
+      __visitation::__base::__visit_alt_at(
+          __rhs.index(),
+          [](auto& __lhs_alt, auto&& __rhs_alt) {
+            __construct_alt(
+                __lhs_alt,
+                _VSTD::forward<decltype(__rhs_alt)>(__rhs_alt).__value);
+          },
+          __lhs, _VSTD::forward<_Rhs>(__rhs));
+      __lhs.__index = __rhs.index();
+    }
+  }
+};
+
+template <class _Traits, _Trait = _Traits::__move_constructible_trait>
+class _LIBCPP_TEMPLATE_VIS __move_constructor;
+
+#define _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(move_constructible_trait,             \
+                                         move_constructor)                     \
+  template <class... _Types>                                                   \
+  class _LIBCPP_TEMPLATE_VIS __move_constructor<__traits<_Types...>,           \
+                                                move_constructible_trait>      \
+      : public __ctor<__traits<_Types...>> {                                   \
+    using __base_type = __ctor<__traits<_Types...>>;                           \
+                                                                               \
+  public:                                                                      \
+    using __base_type::__base_type;                                            \
+    using __base_type::operator=;                                              \
+                                                                               \
+    __move_constructor(const __move_constructor&) = default;                   \
+    move_constructor                                                           \
+    ~__move_constructor() = default;                                           \
+    __move_constructor& operator=(const __move_constructor&) = default;        \
+    __move_constructor& operator=(__move_constructor&&) = default;             \
+  }
+
+_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
+    _Trait::_TriviallyAvailable,
+    __move_constructor(__move_constructor&& __that) = default;);
+
+_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
+    _Trait::_Available,
+    __move_constructor(__move_constructor&& __that) noexcept(
+        __all<is_nothrow_move_constructible_v<_Types>...>::value)
+        : __move_constructor(__valueless_t{}) {
+      this->__generic_construct(*this, _VSTD::move(__that));
+    });
+
+_LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
+    _Trait::_Unavailable,
+    __move_constructor(__move_constructor&&) = delete;);
+
+#undef _LIBCPP_VARIANT_MOVE_CONSTRUCTOR
+
+template <class _Traits, _Trait = _Traits::__copy_constructible_trait>
+class _LIBCPP_TEMPLATE_VIS __copy_constructor;
+
+#define _LIBCPP_VARIANT_COPY_CONSTRUCTOR(copy_constructible_trait,             \
+                                         copy_constructor)                     \
+  template <class... _Types>                                                   \
+  class _LIBCPP_TEMPLATE_VIS __copy_constructor<__traits<_Types...>,          \
+                                                 copy_constructible_trait>     \
+      : public __move_constructor<__traits<_Types...>> {                       \
+    using __base_type = __move_constructor<__traits<_Types...>>;               \
+                                                                               \
+  public:                                                                      \
+    using __base_type::__base_type;                                            \
+    using __base_type::operator=;                                              \
+                                                                               \
+    copy_constructor                                                           \
+    __copy_constructor(__copy_constructor&&) = default;                        \
+    ~__copy_constructor() = default;                                           \
+    __copy_constructor& operator=(const __copy_constructor&) = default;        \
+    __copy_constructor& operator=(__copy_constructor&&) = default;             \
+  }
+
+_LIBCPP_VARIANT_COPY_CONSTRUCTOR(
+    _Trait::_TriviallyAvailable,
+    __copy_constructor(const __copy_constructor& __that) = default;);
+
+_LIBCPP_VARIANT_COPY_CONSTRUCTOR(
+    _Trait::_Available,
+    __copy_constructor(const __copy_constructor& __that)
+        : __copy_constructor(__valueless_t{}) {
+      this->__generic_construct(*this, __that);
+    });
+
+_LIBCPP_VARIANT_COPY_CONSTRUCTOR(
+    _Trait::_Unavailable,
+    __copy_constructor(const __copy_constructor&) = delete;);
+
+#undef _LIBCPP_VARIANT_COPY_CONSTRUCTOR
+
+template <class _Traits>
+class _LIBCPP_TEMPLATE_VIS __assignment : public __copy_constructor<_Traits> {
+  using __base_type = __copy_constructor<_Traits>;
+
+public:
+  using __base_type::__base_type;
+  using __base_type::operator=;
+
+  template <size_t _Ip, class... _Args>
+  inline _LIBCPP_INLINE_VISIBILITY
+  auto& __emplace(_Args&&... __args) {
+    this->__destroy();
+    auto& __res = this->__construct_alt(__access::__base::__get_alt<_Ip>(*this),
+                          _VSTD::forward<_Args>(__args)...);
+    this->__index = _Ip;
+    return __res;
+  }
+
+protected:
+  template <size_t _Ip, class _Tp, class _Arg>
+  inline _LIBCPP_INLINE_VISIBILITY
+  void __assign_alt(__alt<_Ip, _Tp>& __a, _Arg&& __arg) {
+    if (this->index() == _Ip) {
+      __a.__value = _VSTD::forward<_Arg>(__arg);
+    } else {
+      struct {
+        void operator()(true_type) const {
+          __this->__emplace<_Ip>(_VSTD::forward<_Arg>(__arg));
+        }
+        void operator()(false_type) const {
+          __this->__emplace<_Ip>(_Tp(_VSTD::forward<_Arg>(__arg)));
+        }
+        __assignment* __this;
+        _Arg&& __arg;
+      } __impl{this, _VSTD::forward<_Arg>(__arg)};
+      __impl(bool_constant<is_nothrow_constructible_v<_Tp, _Arg> ||
+                           !is_nothrow_move_constructible_v<_Tp>>{});
+    }
+  }
+
+  template <class _That>
+  inline _LIBCPP_INLINE_VISIBILITY
+  void __generic_assign(_That&& __that) {
+    if (this->valueless_by_exception() && __that.valueless_by_exception()) {
+      // do nothing.
+    } else if (__that.valueless_by_exception()) {
+      this->__destroy();
+    } else {
+      __visitation::__base::__visit_alt_at(
+          __that.index(),
+          [this](auto& __this_alt, auto&& __that_alt) {
+            this->__assign_alt(
+                __this_alt,
+                _VSTD::forward<decltype(__that_alt)>(__that_alt).__value);
+          },
+          *this, _VSTD::forward<_That>(__that));
+    }
+  }
+};
+
+template <class _Traits, _Trait = _Traits::__move_assignable_trait>
+class _LIBCPP_TEMPLATE_VIS __move_assignment;
+
+#define _LIBCPP_VARIANT_MOVE_ASSIGNMENT(move_assignable_trait,                 \
+                                        move_assignment)                       \
+  template <class... _Types>                                                   \
+  class _LIBCPP_TEMPLATE_VIS __move_assignment<__traits<_Types...>,           \
+                                                move_assignable_trait>         \
+      : public __assignment<__traits<_Types...>> {                             \
+    using __base_type = __assignment<__traits<_Types...>>;                     \
+                                                                               \
+  public:                                                                      \
+    using __base_type::__base_type;                                            \
+    using __base_type::operator=;                                              \
+                                                                               \
+    __move_assignment(const __move_assignment&) = default;                     \
+    __move_assignment(__move_assignment&&) = default;                          \
+    ~__move_assignment() = default;                                            \
+    __move_assignment& operator=(const __move_assignment&) = default;          \
+    move_assignment                                                            \
+  }
+
+_LIBCPP_VARIANT_MOVE_ASSIGNMENT(
+    _Trait::_TriviallyAvailable,
+    __move_assignment& operator=(__move_assignment&& __that) = default;);
+
+_LIBCPP_VARIANT_MOVE_ASSIGNMENT(
+    _Trait::_Available,
+    __move_assignment& operator=(__move_assignment&& __that) noexcept(
+        __all<(is_nothrow_move_constructible_v<_Types> &&
+               is_nothrow_move_assignable_v<_Types>)...>::value) {
+      this->__generic_assign(_VSTD::move(__that));
+      return *this;
+    });
+
+_LIBCPP_VARIANT_MOVE_ASSIGNMENT(
+    _Trait::_Unavailable,
+    __move_assignment& operator=(__move_assignment&&) = delete;);
+
+#undef _LIBCPP_VARIANT_MOVE_ASSIGNMENT
+
+template <class _Traits, _Trait = _Traits::__copy_assignable_trait>
+class _LIBCPP_TEMPLATE_VIS __copy_assignment;
+
+#define _LIBCPP_VARIANT_COPY_ASSIGNMENT(copy_assignable_trait,                 \
+                                        copy_assignment)                       \
+  template <class... _Types>                                                   \
+  class _LIBCPP_TEMPLATE_VIS __copy_assignment<__traits<_Types...>,           \
+                                                copy_assignable_trait>         \
+      : public __move_assignment<__traits<_Types...>> {                        \
+    using __base_type = __move_assignment<__traits<_Types...>>;                \
+                                                                               \
+  public:                                                                      \
+    using __base_type::__base_type;                                            \
+    using __base_type::operator=;                                              \
+                                                                               \
+    __copy_assignment(const __copy_assignment&) = default;                     \
+    __copy_assignment(__copy_assignment&&) = default;                          \
+    ~__copy_assignment() = default;                                            \
+    copy_assignment                                                            \
+    __copy_assignment& operator=(__copy_assignment&&) = default;               \
+  }
+
+_LIBCPP_VARIANT_COPY_ASSIGNMENT(
+    _Trait::_TriviallyAvailable,
+    __copy_assignment& operator=(const __copy_assignment& __that) = default;);
+
+_LIBCPP_VARIANT_COPY_ASSIGNMENT(
+    _Trait::_Available,
+    __copy_assignment& operator=(const __copy_assignment& __that) {
+      this->__generic_assign(__that);
+      return *this;
+    });
+
+_LIBCPP_VARIANT_COPY_ASSIGNMENT(
+    _Trait::_Unavailable,
+    __copy_assignment& operator=(const __copy_assignment&) = delete;);
+
+#undef _LIBCPP_VARIANT_COPY_ASSIGNMENT
+
+template <class... _Types>
+class _LIBCPP_TEMPLATE_VIS __impl
+    : public __copy_assignment<__traits<_Types...>> {
+  using __base_type = __copy_assignment<__traits<_Types...>>;
+
+public:
+  using __base_type::__base_type;
+  using __base_type::operator=;
+
+  template <size_t _Ip, class _Arg>
+  inline _LIBCPP_INLINE_VISIBILITY
+  void __assign(_Arg&& __arg) {
+    this->__assign_alt(__access::__base::__get_alt<_Ip>(*this),
+                       _VSTD::forward<_Arg>(__arg));
+  }
+
+  inline _LIBCPP_INLINE_VISIBILITY
+  void __swap(__impl& __that)  {
+    if (this->valueless_by_exception() && __that.valueless_by_exception()) {
+      // do nothing.
+    } else if (this->index() == __that.index()) {
+      __visitation::__base::__visit_alt_at(
+          this->index(),
+          [](auto& __this_alt, auto& __that_alt) {
+            using _VSTD::swap;
+            swap(__this_alt.__value, __that_alt.__value);
+          },
+          *this,
+          __that);
+    } else {
+      __impl* __lhs = this;
+      __impl* __rhs = _VSTD::addressof(__that);
+      if (__lhs->__move_nothrow() && !__rhs->__move_nothrow()) {
+        _VSTD::swap(__lhs, __rhs);
+      }
+      __impl __tmp(_VSTD::move(*__rhs));
+#ifndef _LIBCPP_NO_EXCEPTIONS
+      if constexpr (__all<is_nothrow_move_constructible_v<_Types>...>::value) {
+        this->__generic_construct(*__rhs, _VSTD::move(*__lhs));
+      } else {
+      // EXTENSION: When the move construction of `__lhs` into `__rhs` throws
+      // and `__tmp` is nothrow move constructible then we move `__tmp` back
+      // into `__rhs` and provide the strong exception safety guarantee.
+      try {
+        this->__generic_construct(*__rhs, _VSTD::move(*__lhs));
+      } catch (...) {
+        if (__tmp.__move_nothrow()) {
+          this->__generic_construct(*__rhs, _VSTD::move(__tmp));
+        }
+        throw;
+      }
+      }
+#else
+      // this isn't consolidated with the `if constexpr` branch above due to
+      // `throw` being ill-formed with exceptions disabled even when discarded.
+      this->__generic_construct(*__rhs, _VSTD::move(*__lhs));
+#endif
+      this->__generic_construct(*__lhs, _VSTD::move(__tmp));
+    }
+  }
+
+private:
+  inline _LIBCPP_INLINE_VISIBILITY
+  bool __move_nothrow() const {
+    constexpr bool __results[] = {is_nothrow_move_constructible_v<_Types>...};
+    return this->valueless_by_exception() || __results[this->index()];
+  }
+};
+
+struct __no_narrowing_check {
+  template <class _Dest, class _Source>
+  using _Apply = __identity<_Dest>;
+};
+
+struct __narrowing_check {
+  template <class _Dest>
+  static auto __test_impl(_Dest (&&)[1]) -> __identity<_Dest>;
+  template <class _Dest, class _Source>
+  using _Apply _LIBCPP_NODEBUG = decltype(__test_impl<_Dest>({declval<_Source>()}));
+};
+
+template <class _Dest, class _Source>
+using __check_for_narrowing _LIBCPP_NODEBUG =
+  typename _If<
+#ifdef _LIBCPP_ENABLE_NARROWING_CONVERSIONS_IN_VARIANT
+    false &&
+#endif
+    is_arithmetic<_Dest>::value,
+    __narrowing_check,
+    __no_narrowing_check
+  >::template _Apply<_Dest, _Source>;
+
+template <class _Tp, size_t _Idx>
+struct __overload {
+  template <class _Up>
+  auto operator()(_Tp, _Up&&) const -> __check_for_narrowing<_Tp, _Up>;
+};
+
+template <class _Tp, size_t>
+struct __overload_bool  {
+  template <class _Up, class _Ap = __uncvref_t<_Up>>
+  auto operator()(bool, _Up&&) const
+      -> enable_if_t<is_same_v<_Ap, bool>, __identity<_Tp>>;
+};
+
+template <size_t _Idx>
+struct __overload<bool, _Idx> : __overload_bool<bool, _Idx> {};
+template <size_t _Idx>
+struct __overload<bool const, _Idx> : __overload_bool<bool const, _Idx> {};
+template <size_t _Idx>
+struct __overload<bool volatile, _Idx> : __overload_bool<bool volatile, _Idx> {};
+template <size_t _Idx>
+struct __overload<bool const volatile, _Idx> : __overload_bool<bool const volatile, _Idx> {};
+
+template <class ..._Bases>
+struct __all_overloads : _Bases... {
+  void operator()() const;
+  using _Bases::operator()...;
+};
+
+// Change metaprogramming to satisfy MSVC. It doesn't like expression
+// __overload<_Types, _Idx>... when _Types comes from using parameter but
+// _Idx comes from structure template parameter. So I made them both
+// structure template parameters.
+template <class _IdxSeq, class ..._Types>
+struct __make_overloads_imp;
+
+template <size_t ..._Idx, class ..._Types>
+struct __make_overloads_imp<__tuple_indices<_Idx...>, _Types... > {
+  using _Apply _LIBCPP_NODEBUG = __all_overloads<__overload<_Types, _Idx>...>;
+};
+
+template <class ..._Types>
+using _MakeOverloads _LIBCPP_NODEBUG = typename __make_overloads_imp<
+    __make_indices_imp<_Sizeof<_Types...>::value, 0>, _Types...>::_Apply;
+
+template <class _Tp, class... _Types>
+using __best_match_t =
+    typename invoke_result_t<_MakeOverloads<_Types...>, _Tp, _Tp>::type;
+
+} // __variant_detail
+
+template <class... _Types>
+class _LIBCPP_TEMPLATE_VIS variant
+    : private __sfinae_ctor_base<
+          __all<is_copy_constructible_v<_Types>...>::value,
+          __all<is_move_constructible_v<_Types>...>::value>,
+      private __sfinae_assign_base<
+          __all<(is_copy_constructible_v<_Types> &&
+                 is_copy_assignable_v<_Types>)...>::value,
+          __all<(is_move_constructible_v<_Types> &&
+                 is_move_assignable_v<_Types>)...>::value> {
+  static_assert(0 < sizeof...(_Types),
+                "variant must consist of at least one alternative.");
+
+  static_assert(__all<!is_array_v<_Types>...>::value,
+                "variant can not have an array type as an alternative.");
+
+  static_assert(__all<!is_reference_v<_Types>...>::value,
+                "variant can not have a reference type as an alternative.");
+
+  static_assert(__all<!is_void_v<_Types>...>::value,
+                "variant can not have a void type as an alternative.");
+
+  using __first_type = variant_alternative_t<0, variant>;
+
+public:
+  template <bool _Dummy = true,
+            enable_if_t<__dependent_type<is_default_constructible<__first_type>,
+                                         _Dummy>::value,
+                        int> = 0>
+  inline _LIBCPP_INLINE_VISIBILITY
+  constexpr variant() noexcept(is_nothrow_default_constructible_v<__first_type>)
+      : __impl(in_place_index<0>) {}
+
+  variant(const variant&) = default;
+  variant(variant&&) = default;
+
+  template <
+      class _Arg,
+      enable_if_t<!is_same_v<__uncvref_t<_Arg>, variant>, int> = 0,
+      enable_if_t<!__is_inplace_type<__uncvref_t<_Arg>>::value, int> = 0,
+      enable_if_t<!__is_inplace_index<__uncvref_t<_Arg>>::value, int> = 0,
+      class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>,
+      size_t _Ip =
+          __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
+      enable_if_t<is_constructible_v<_Tp, _Arg>, int> = 0>
+  inline _LIBCPP_INLINE_VISIBILITY
+  constexpr variant(_Arg&& __arg) noexcept(
+      is_nothrow_constructible_v<_Tp, _Arg>)
+      : __impl(in_place_index<_Ip>, _VSTD::forward<_Arg>(__arg)) {}
+
+  template <size_t _Ip, class... _Args,
+            class = enable_if_t<(_Ip < sizeof...(_Types)), int>,
+            class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
+            enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
+  inline _LIBCPP_INLINE_VISIBILITY
+  explicit constexpr variant(
+      in_place_index_t<_Ip>,
+      _Args&&... __args) noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
+      : __impl(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {}
+
+  template <
+      size_t _Ip,
+      class _Up,
+      class... _Args,
+      enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,
+      class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
+      enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
+                  int> = 0>
+  inline _LIBCPP_INLINE_VISIBILITY
+  explicit constexpr variant(
+      in_place_index_t<_Ip>,
+      initializer_list<_Up> __il,
+      _Args&&... __args) noexcept(
+      is_nothrow_constructible_v<_Tp, initializer_list<_Up>&, _Args...>)
+      : __impl(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {}
+
+  template <
+      class _Tp,
+      class... _Args,
+      size_t _Ip =
+          __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
+      enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
+  inline _LIBCPP_INLINE_VISIBILITY
+  explicit constexpr variant(in_place_type_t<_Tp>, _Args&&... __args) noexcept(
+      is_nothrow_constructible_v<_Tp, _Args...>)
+      : __impl(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {}
+
+  template <
+      class _Tp,
+      class _Up,
+      class... _Args,
+      size_t _Ip =
+          __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
+      enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
+                  int> = 0>
+  inline _LIBCPP_INLINE_VISIBILITY
+  explicit constexpr variant(
+      in_place_type_t<_Tp>,
+      initializer_list<_Up> __il,
+      _Args&&... __args) noexcept(
+      is_nothrow_constructible_v<_Tp, initializer_list< _Up>&, _Args...>)
+      : __impl(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {}
+
+  ~variant() = default;
+
+  variant& operator=(const variant&) = default;
+  variant& operator=(variant&&) = default;
+
+  template <
+      class _Arg,
+      enable_if_t<!is_same_v<__uncvref_t<_Arg>, variant>, int> = 0,
+      class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>,
+      size_t _Ip =
+          __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
+      enable_if_t<is_assignable_v<_Tp&, _Arg> && is_constructible_v<_Tp, _Arg>,
+                  int> = 0>
+  inline _LIBCPP_INLINE_VISIBILITY
+  variant& operator=(_Arg&& __arg) noexcept(
+      is_nothrow_assignable_v<_Tp&, _Arg> &&
+      is_nothrow_constructible_v<_Tp, _Arg>) {
+    __impl.template __assign<_Ip>(_VSTD::forward<_Arg>(__arg));
+    return *this;
+  }
+
+  template <
+      size_t _Ip,
+      class... _Args,
+      enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,
+      class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
+      enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
+  inline _LIBCPP_INLINE_VISIBILITY
+  _Tp& emplace(_Args&&... __args) {
+    return __impl.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...);
+  }
+
+  template <
+      size_t _Ip,
+      class _Up,
+      class... _Args,
+      enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,
+      class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
+      enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
+                  int> = 0>
+  inline _LIBCPP_INLINE_VISIBILITY
+  _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) {
+    return __impl.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...);
+  }
+
+  template <
+      class _Tp,
+      class... _Args,
+      size_t _Ip =
+          __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
+      enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
+  inline _LIBCPP_INLINE_VISIBILITY
+  _Tp& emplace(_Args&&... __args) {
+    return __impl.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...);
+  }
+
+  template <
+      class _Tp,
+      class _Up,
+      class... _Args,
+      size_t _Ip =
+          __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
+      enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
+                  int> = 0>
+  inline _LIBCPP_INLINE_VISIBILITY
+  _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) {
+    return __impl.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...);
+  }
+
+  inline _LIBCPP_INLINE_VISIBILITY
+  constexpr bool valueless_by_exception() const noexcept {
+    return __impl.valueless_by_exception();
+  }
+
+  inline _LIBCPP_INLINE_VISIBILITY
+  constexpr size_t index() const noexcept { return __impl.index(); }
+
+  template <
+      bool _Dummy = true,
+      enable_if_t<
+          __all<(
+              __dependent_type<is_move_constructible<_Types>, _Dummy>::value &&
+              __dependent_type<is_swappable<_Types>, _Dummy>::value)...>::value,
+          int> = 0>
+  inline _LIBCPP_INLINE_VISIBILITY
+  void swap(variant& __that) noexcept(
+      __all<(is_nothrow_move_constructible_v<_Types> &&
+             is_nothrow_swappable_v<_Types>)...>::value) {
+    __impl.__swap(__that.__impl);
+  }
+
+private:
+  __variant_detail::__impl<_Types...> __impl;
+
+  friend struct __variant_detail::__access::__variant;
+  friend struct __variant_detail::__visitation::__variant;
+};
+
+template <size_t _Ip, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool __holds_alternative(const variant<_Types...>& __v) noexcept {
+  return __v.index() == _Ip;
+}
+
+template <class _Tp, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool holds_alternative(const variant<_Types...>& __v) noexcept {
+  return __holds_alternative<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
+}
+
+template <size_t _Ip, class _Vp>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
+constexpr auto&& __generic_get(_Vp&& __v) {
+  using __variant_detail::__access::__variant;
+  if (!__holds_alternative<_Ip>(__v)) {
+    __throw_bad_variant_access();
+  }
+  return __variant::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v)).__value;
+}
+
+template <size_t _Ip, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
+constexpr variant_alternative_t<_Ip, variant<_Types...>>& get(
+    variant<_Types...>& __v) {
+  static_assert(_Ip < sizeof...(_Types));
+  static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
+  return __generic_get<_Ip>(__v);
+}
+
+template <size_t _Ip, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
+constexpr variant_alternative_t<_Ip, variant<_Types...>>&& get(
+    variant<_Types...>&& __v) {
+  static_assert(_Ip < sizeof...(_Types));
+  static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
+  return __generic_get<_Ip>(_VSTD::move(__v));
+}
+
+template <size_t _Ip, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
+constexpr const variant_alternative_t<_Ip, variant<_Types...>>& get(
+    const variant<_Types...>& __v) {
+  static_assert(_Ip < sizeof...(_Types));
+  static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
+  return __generic_get<_Ip>(__v);
+}
+
+template <size_t _Ip, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
+constexpr const variant_alternative_t<_Ip, variant<_Types...>>&& get(
+    const variant<_Types...>&& __v) {
+  static_assert(_Ip < sizeof...(_Types));
+  static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
+  return __generic_get<_Ip>(_VSTD::move(__v));
+}
+
+template <class _Tp, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
+constexpr _Tp& get(variant<_Types...>& __v) {
+  static_assert(!is_void_v<_Tp>);
+  return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
+}
+
+template <class _Tp, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
+constexpr _Tp&& get(variant<_Types...>&& __v) {
+  static_assert(!is_void_v<_Tp>);
+  return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(
+      _VSTD::move(__v));
+}
+
+template <class _Tp, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
+constexpr const _Tp& get(const variant<_Types...>& __v) {
+  static_assert(!is_void_v<_Tp>);
+  return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
+}
+
+template <class _Tp, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS
+constexpr const _Tp&& get(const variant<_Types...>&& __v) {
+  static_assert(!is_void_v<_Tp>);
+  return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(
+      _VSTD::move(__v));
+}
+
+template <size_t _Ip, class _Vp>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr auto* __generic_get_if(_Vp* __v) noexcept {
+  using __variant_detail::__access::__variant;
+  return __v && __holds_alternative<_Ip>(*__v)
+             ? _VSTD::addressof(__variant::__get_alt<_Ip>(*__v).__value)
+             : nullptr;
+}
+
+template <size_t _Ip, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr add_pointer_t<variant_alternative_t<_Ip, variant<_Types...>>>
+get_if(variant<_Types...>* __v) noexcept {
+  static_assert(_Ip < sizeof...(_Types));
+  static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
+  return __generic_get_if<_Ip>(__v);
+}
+
+template <size_t _Ip, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr add_pointer_t<const variant_alternative_t<_Ip, variant<_Types...>>>
+get_if(const variant<_Types...>* __v) noexcept {
+  static_assert(_Ip < sizeof...(_Types));
+  static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
+  return __generic_get_if<_Ip>(__v);
+}
+
+template <class _Tp, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr add_pointer_t<_Tp>
+get_if(variant<_Types...>* __v) noexcept {
+  static_assert(!is_void_v<_Tp>);
+  return _VSTD::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
+}
+
+template <class _Tp, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr add_pointer_t<const _Tp>
+get_if(const variant<_Types...>* __v) noexcept {
+  static_assert(!is_void_v<_Tp>);
+  return _VSTD::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
+}
+
+template <class _Operator>
+struct __convert_to_bool {
+  template <class _T1, class _T2>
+  _LIBCPP_INLINE_VISIBILITY constexpr bool operator()(_T1 && __t1, _T2&& __t2) const {
+    static_assert(is_convertible<decltype(_Operator{}(_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2))), bool>::value,
+        "the relational operator does not return a type which is implicitly convertible to bool");
+    return _Operator{}(_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
+  }
+};
+
+template <class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool operator==(const variant<_Types...>& __lhs,
+                          const variant<_Types...>& __rhs) {
+  using __variant_detail::__visitation::__variant;
+  if (__lhs.index() != __rhs.index()) return false;
+  if (__lhs.valueless_by_exception()) return true;
+  return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<equal_to<>>{}, __lhs, __rhs);
+}
+
+template <class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool operator!=(const variant<_Types...>& __lhs,
+                          const variant<_Types...>& __rhs) {
+  using __variant_detail::__visitation::__variant;
+  if (__lhs.index() != __rhs.index()) return true;
+  if (__lhs.valueless_by_exception()) return false;
+  return __variant::__visit_value_at(
+      __lhs.index(), __convert_to_bool<not_equal_to<>>{}, __lhs, __rhs);
+}
+
+template <class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool operator<(const variant<_Types...>& __lhs,
+                         const variant<_Types...>& __rhs) {
+  using __variant_detail::__visitation::__variant;
+  if (__rhs.valueless_by_exception()) return false;
+  if (__lhs.valueless_by_exception()) return true;
+  if (__lhs.index() < __rhs.index()) return true;
+  if (__lhs.index() > __rhs.index()) return false;
+  return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<less<>>{}, __lhs, __rhs);
+}
+
+template <class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool operator>(const variant<_Types...>& __lhs,
+                         const variant<_Types...>& __rhs) {
+  using __variant_detail::__visitation::__variant;
+  if (__lhs.valueless_by_exception()) return false;
+  if (__rhs.valueless_by_exception()) return true;
+  if (__lhs.index() > __rhs.index()) return true;
+  if (__lhs.index() < __rhs.index()) return false;
+  return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<greater<>>{}, __lhs, __rhs);
+}
+
+template <class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool operator<=(const variant<_Types...>& __lhs,
+                          const variant<_Types...>& __rhs) {
+  using __variant_detail::__visitation::__variant;
+  if (__lhs.valueless_by_exception()) return true;
+  if (__rhs.valueless_by_exception()) return false;
+  if (__lhs.index() < __rhs.index()) return true;
+  if (__lhs.index() > __rhs.index()) return false;
+  return __variant::__visit_value_at(
+      __lhs.index(), __convert_to_bool<less_equal<>>{}, __lhs, __rhs);
+}
+
+template <class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr bool operator>=(const variant<_Types...>& __lhs,
+                          const variant<_Types...>& __rhs) {
+  using __variant_detail::__visitation::__variant;
+  if (__rhs.valueless_by_exception()) return true;
+  if (__lhs.valueless_by_exception()) return false;
+  if (__lhs.index() > __rhs.index()) return true;
+  if (__lhs.index() < __rhs.index()) return false;
+  return __variant::__visit_value_at(
+      __lhs.index(), __convert_to_bool<greater_equal<>>{}, __lhs, __rhs);
+}
+
+template <class... _Vs>
+inline _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr void
+    __throw_if_valueless(_Vs&&... __vs) {
+  const bool __valueless =
+      (... || _VSTD::__as_variant(__vs).valueless_by_exception());
+  if (__valueless) {
+      __throw_bad_variant_access();
+    }
+  }
+
+template <
+    class _Visitor, class... _Vs,
+    typename = void_t<decltype(_VSTD::__as_variant(declval<_Vs>()))...> >
+inline _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr
+    decltype(auto) visit(_Visitor&& __visitor, _Vs&&... __vs) {
+  using __variant_detail::__visitation::__variant;
+  _VSTD::__throw_if_valueless(_VSTD::forward<_Vs>(__vs)...);
+  return __variant::__visit_value(_VSTD::forward<_Visitor>(__visitor),
+                                  _VSTD::forward<_Vs>(__vs)...);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <
+    class _Rp, class _Visitor, class... _Vs,
+    typename = void_t<decltype(_VSTD::__as_variant(declval<_Vs>()))...> >
+inline _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr _Rp
+    visit(_Visitor&& __visitor, _Vs&&... __vs) {
+  using __variant_detail::__visitation::__variant;
+  _VSTD::__throw_if_valueless(_VSTD::forward<_Vs>(__vs)...);
+  return __variant::__visit_value<_Rp>(_VSTD::forward<_Visitor>(__visitor),
+                                       _VSTD::forward<_Vs>(__vs)...);
+}
+#endif
+
+template <class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+auto swap(variant<_Types...>& __lhs, variant<_Types...>& __rhs)
+  noexcept(noexcept(__lhs.swap(__rhs)))
+  -> decltype(      __lhs.swap(__rhs))
+  { return          __lhs.swap(__rhs); }
+
+template <class... _Types>
+struct _LIBCPP_TEMPLATE_VIS hash<
+    __enable_hash_helper<variant<_Types...>, remove_const_t<_Types>...>> {
+  using argument_type = variant<_Types...>;
+  using result_type = size_t;
+
+  inline _LIBCPP_INLINE_VISIBILITY
+  result_type operator()(const argument_type& __v) const {
+    using __variant_detail::__visitation::__variant;
+    size_t __res =
+        __v.valueless_by_exception()
+               ? 299792458 // Random value chosen by the universe upon creation
+               : __variant::__visit_alt(
+                     [](const auto& __alt) {
+                       using __alt_type = __uncvref_t<decltype(__alt)>;
+                       using __value_type = remove_const_t<
+                         typename __alt_type::__value_type>;
+                       return hash<__value_type>{}(__alt.__value);
+                     },
+                     __v);
+    return __hash_combine(__res, hash<size_t>{}(__v.index()));
+  }
+};
+
+// __unchecked_get is the same as std::get, except, it is UB to use it with the wrong
+// type whereas std::get will throw or returning nullptr. This makes it faster than
+// std::get.
+template <size_t _Ip, class _Vp>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr auto&& __unchecked_get(_Vp&& __v) noexcept {
+  using __variant_detail::__access::__variant;
+  return __variant::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v)).__value;
+}
+
+template <class _Tp, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr auto&& __unchecked_get(const variant<_Types...>& __v) noexcept {
+  return __unchecked_get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
+}
+
+template <class _Tp, class... _Types>
+inline _LIBCPP_INLINE_VISIBILITY
+constexpr auto&& __unchecked_get(variant<_Types...>& __v) noexcept {
+  return __unchecked_get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
+}
+
+#endif // _LIBCPP_STD_VER > 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_VARIANT
diff --git a/contrib/libs/cxxsupp/libcxx/include/vector b/contrib/libs/cxxsupp/libcxx/include/vector
new file mode 100644
index 00000000000..c02253c751c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/vector
@@ -0,0 +1,3475 @@
+// -*- C++ -*-
+//===------------------------------ vector --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_VECTOR
+#define _LIBCPP_VECTOR
+
+/*
+    vector synopsis
+
+namespace std
+{
+
+template <class T, class Allocator = allocator<T> >
+class vector
+{
+public:
+    typedef T                                        value_type;
+    typedef Allocator                                allocator_type;
+    typedef typename allocator_type::reference       reference;
+    typedef typename allocator_type::const_reference const_reference;
+    typedef implementation-defined                   iterator;
+    typedef implementation-defined                   const_iterator;
+    typedef typename allocator_type::size_type       size_type;
+    typedef typename allocator_type::difference_type difference_type;
+    typedef typename allocator_type::pointer         pointer;
+    typedef typename allocator_type::const_pointer   const_pointer;
+    typedef std::reverse_iterator<iterator>          reverse_iterator;
+    typedef std::reverse_iterator<const_iterator>    const_reverse_iterator;
+
+    vector()
+        noexcept(is_nothrow_default_constructible<allocator_type>::value);
+    explicit vector(const allocator_type&);
+    explicit vector(size_type n);
+    explicit vector(size_type n, const allocator_type&); // C++14
+    vector(size_type n, const value_type& value, const allocator_type& = allocator_type());
+    template <class InputIterator>
+        vector(InputIterator first, InputIterator last, const allocator_type& = allocator_type());
+    vector(const vector& x);
+    vector(vector&& x)
+        noexcept(is_nothrow_move_constructible<allocator_type>::value);
+    vector(initializer_list<value_type> il);
+    vector(initializer_list<value_type> il, const allocator_type& a);
+    ~vector();
+    vector& operator=(const vector& x);
+    vector& operator=(vector&& x)
+        noexcept(
+             allocator_type::propagate_on_container_move_assignment::value ||
+             allocator_type::is_always_equal::value); // C++17
+    vector& operator=(initializer_list<value_type> il);
+    template <class InputIterator>
+        void assign(InputIterator first, InputIterator last);
+    void assign(size_type n, const value_type& u);
+    void assign(initializer_list<value_type> il);
+
+    allocator_type get_allocator() const noexcept;
+
+    iterator               begin() noexcept;
+    const_iterator         begin()   const noexcept;
+    iterator               end() noexcept;
+    const_iterator         end()     const noexcept;
+
+    reverse_iterator       rbegin() noexcept;
+    const_reverse_iterator rbegin()  const noexcept;
+    reverse_iterator       rend() noexcept;
+    const_reverse_iterator rend()    const noexcept;
+
+    const_iterator         cbegin()  const noexcept;
+    const_iterator         cend()    const noexcept;
+    const_reverse_iterator crbegin() const noexcept;
+    const_reverse_iterator crend()   const noexcept;
+
+    size_type size() const noexcept;
+    size_type max_size() const noexcept;
+    size_type capacity() const noexcept;
+    bool empty() const noexcept;
+    void reserve(size_type n);
+    void shrink_to_fit() noexcept;
+
+    reference       operator[](size_type n);
+    const_reference operator[](size_type n) const;
+    reference       at(size_type n);
+    const_reference at(size_type n) const;
+
+    reference       front();
+    const_reference front() const;
+    reference       back();
+    const_reference back() const;
+
+    value_type*       data() noexcept;
+    const value_type* data() const noexcept;
+
+    void push_back(const value_type& x);
+    void push_back(value_type&& x);
+    template <class... Args>
+        reference emplace_back(Args&&... args); // reference in C++17
+    void pop_back();
+
+    template <class... Args> iterator emplace(const_iterator position, Args&&... args);
+    iterator insert(const_iterator position, const value_type& x);
+    iterator insert(const_iterator position, value_type&& x);
+    iterator insert(const_iterator position, size_type n, const value_type& x);
+    template <class InputIterator>
+        iterator insert(const_iterator position, InputIterator first, InputIterator last);
+    iterator insert(const_iterator position, initializer_list<value_type> il);
+
+    iterator erase(const_iterator position);
+    iterator erase(const_iterator first, const_iterator last);
+
+    void clear() noexcept;
+
+    void resize(size_type sz);
+    void resize(size_type sz, const value_type& c);
+
+    void swap(vector&)
+        noexcept(allocator_traits<allocator_type>::propagate_on_container_swap::value ||
+                 allocator_traits<allocator_type>::is_always_equal::value);  // C++17
+
+    bool __invariants() const;
+};
+
+template <class Allocator = allocator<T> >
+class vector<bool, Allocator>
+{
+public:
+    typedef bool                                     value_type;
+    typedef Allocator                                allocator_type;
+    typedef implementation-defined                   iterator;
+    typedef implementation-defined                   const_iterator;
+    typedef typename allocator_type::size_type       size_type;
+    typedef typename allocator_type::difference_type difference_type;
+    typedef iterator                                 pointer;
+    typedef const_iterator                           const_pointer;
+    typedef std::reverse_iterator<iterator>          reverse_iterator;
+    typedef std::reverse_iterator<const_iterator>    const_reverse_iterator;
+
+    class reference
+    {
+    public:
+        reference(const reference&) noexcept;
+        operator bool() const noexcept;
+        reference& operator=(bool x) noexcept;
+        reference& operator=(const reference& x) noexcept;
+        iterator operator&() const noexcept;
+        void flip() noexcept;
+    };
+
+    class const_reference
+    {
+    public:
+        const_reference(const reference&) noexcept;
+        operator bool() const noexcept;
+        const_iterator operator&() const noexcept;
+    };
+
+    vector()
+        noexcept(is_nothrow_default_constructible<allocator_type>::value);
+    explicit vector(const allocator_type&);
+    explicit vector(size_type n, const allocator_type& a = allocator_type()); // C++14
+    vector(size_type n, const value_type& value, const allocator_type& = allocator_type());
+    template <class InputIterator>
+        vector(InputIterator first, InputIterator last, const allocator_type& = allocator_type());
+    vector(const vector& x);
+    vector(vector&& x)
+        noexcept(is_nothrow_move_constructible<allocator_type>::value);
+    vector(initializer_list<value_type> il);
+    vector(initializer_list<value_type> il, const allocator_type& a);
+    ~vector();
+    vector& operator=(const vector& x);
+    vector& operator=(vector&& x)
+        noexcept(
+             allocator_type::propagate_on_container_move_assignment::value ||
+             allocator_type::is_always_equal::value); // C++17
+    vector& operator=(initializer_list<value_type> il);
+    template <class InputIterator>
+        void assign(InputIterator first, InputIterator last);
+    void assign(size_type n, const value_type& u);
+    void assign(initializer_list<value_type> il);
+
+    allocator_type get_allocator() const noexcept;
+
+    iterator               begin() noexcept;
+    const_iterator         begin()   const noexcept;
+    iterator               end() noexcept;
+    const_iterator         end()     const noexcept;
+
+    reverse_iterator       rbegin() noexcept;
+    const_reverse_iterator rbegin()  const noexcept;
+    reverse_iterator       rend() noexcept;
+    const_reverse_iterator rend()    const noexcept;
+
+    const_iterator         cbegin()  const noexcept;
+    const_iterator         cend()    const noexcept;
+    const_reverse_iterator crbegin() const noexcept;
+    const_reverse_iterator crend()   const noexcept;
+
+    size_type size() const noexcept;
+    size_type max_size() const noexcept;
+    size_type capacity() const noexcept;
+    bool empty() const noexcept;
+    void reserve(size_type n);
+    void shrink_to_fit() noexcept;
+
+    reference       operator[](size_type n);
+    const_reference operator[](size_type n) const;
+    reference       at(size_type n);
+    const_reference at(size_type n) const;
+
+    reference       front();
+    const_reference front() const;
+    reference       back();
+    const_reference back() const;
+
+    void push_back(const value_type& x);
+    template <class... Args> reference emplace_back(Args&&... args);  // C++14; reference in C++17
+    void pop_back();
+
+    template <class... Args> iterator emplace(const_iterator position, Args&&... args);  // C++14
+    iterator insert(const_iterator position, const value_type& x);
+    iterator insert(const_iterator position, size_type n, const value_type& x);
+    template <class InputIterator>
+        iterator insert(const_iterator position, InputIterator first, InputIterator last);
+    iterator insert(const_iterator position, initializer_list<value_type> il);
+
+    iterator erase(const_iterator position);
+    iterator erase(const_iterator first, const_iterator last);
+
+    void clear() noexcept;
+
+    void resize(size_type sz);
+    void resize(size_type sz, value_type x);
+
+    void swap(vector&)
+        noexcept(allocator_traits<allocator_type>::propagate_on_container_swap::value ||
+                 allocator_traits<allocator_type>::is_always_equal::value);  // C++17
+    void flip() noexcept;
+
+    bool __invariants() const;
+};
+
+template <class InputIterator, class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
+   vector(InputIterator, InputIterator, Allocator = Allocator())
+   -> vector<typename iterator_traits<InputIterator>::value_type, Allocator>;
+
+template <class Allocator> struct hash<std::vector<bool, Allocator>>;
+
+template <class T, class Allocator> bool operator==(const vector<T,Allocator>& x, const vector<T,Allocator>& y);
+template <class T, class Allocator> bool operator< (const vector<T,Allocator>& x, const vector<T,Allocator>& y);
+template <class T, class Allocator> bool operator!=(const vector<T,Allocator>& x, const vector<T,Allocator>& y);
+template <class T, class Allocator> bool operator> (const vector<T,Allocator>& x, const vector<T,Allocator>& y);
+template <class T, class Allocator> bool operator>=(const vector<T,Allocator>& x, const vector<T,Allocator>& y);
+template <class T, class Allocator> bool operator<=(const vector<T,Allocator>& x, const vector<T,Allocator>& y);
+
+template <class T, class Allocator>
+void swap(vector<T,Allocator>& x, vector<T,Allocator>& y)
+    noexcept(noexcept(x.swap(y)));
+
+template <class T, class Allocator, class U>
+typename vector<T, Allocator>::size_type
+erase(vector<T, Allocator>& c, const U& value);       // C++20
+template <class T, class Allocator, class Predicate>
+typename vector<T, Allocator>::size_type
+erase_if(vector<T, Allocator>& c, Predicate pred);    // C++20
+
+}  // std
+
+*/
+
+#include <__config>
+#include <__bit_reference>
+#include <__debug>
+#include <__functional_base>
+#include <__iterator/wrap_iter.h>
+#include <__split_buffer>
+#include <__utility/forward.h>
+#include <algorithm>
+#include <climits>
+#include <compare>
+#include <cstdlib>
+#include <cstring>
+#include <initializer_list>
+#include <iosfwd> // for forward declaration of vector
+#include <limits>
+#include <memory>
+#include <stdexcept>
+#include <type_traits>
+#include <version>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <bool>
+struct __vector_base_common;
+
+template <>
+struct __vector_base_common<true> {
+    // Both are defined in vector.cpp
+    _LIBCPP_NORETURN _LIBCPP_EXPORTED_FROM_ABI void __throw_length_error() const;
+    _LIBCPP_NORETURN _LIBCPP_EXPORTED_FROM_ABI void __throw_out_of_range() const;
+};
+
+template <class _Tp, class _Allocator>
+class __vector_base
+    : protected __vector_base_common<true> // This base class is historical, but it needs to remain for ABI compatibility
+{
+public:
+    typedef _Allocator                               allocator_type;
+    typedef allocator_traits<allocator_type>         __alloc_traits;
+    typedef typename __alloc_traits::size_type       size_type;
+protected:
+    typedef _Tp                                      value_type;
+    typedef value_type&                              reference;
+    typedef const value_type&                        const_reference;
+    typedef typename __alloc_traits::difference_type difference_type;
+    typedef typename __alloc_traits::pointer         pointer;
+    typedef typename __alloc_traits::const_pointer   const_pointer;
+    typedef pointer                                  iterator;
+    typedef const_pointer                            const_iterator;
+
+    pointer                                         __begin_;
+    pointer                                         __end_;
+    __compressed_pair<pointer, allocator_type> __end_cap_;
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type& __alloc() _NOEXCEPT
+        {return __end_cap_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    const allocator_type& __alloc() const _NOEXCEPT
+        {return __end_cap_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    pointer& __end_cap() _NOEXCEPT
+        {return __end_cap_.first();}
+    _LIBCPP_INLINE_VISIBILITY
+    const pointer& __end_cap() const _NOEXCEPT
+        {return __end_cap_.first();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    __vector_base()
+        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value);
+    _LIBCPP_INLINE_VISIBILITY __vector_base(const allocator_type& __a);
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY __vector_base(allocator_type&& __a) _NOEXCEPT;
+#endif
+    ~__vector_base();
+
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT {__destruct_at_end(__begin_);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type capacity() const _NOEXCEPT
+        {return static_cast<size_type>(__end_cap() - __begin_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __destruct_at_end(pointer __new_last) _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __vector_base& __c)
+        {__copy_assign_alloc(__c, integral_constant<bool,
+                      __alloc_traits::propagate_on_container_copy_assignment::value>());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__vector_base& __c)
+        _NOEXCEPT_(
+            !__alloc_traits::propagate_on_container_move_assignment::value ||
+            is_nothrow_move_assignable<allocator_type>::value)
+        {__move_assign_alloc(__c, integral_constant<bool,
+                      __alloc_traits::propagate_on_container_move_assignment::value>());}
+
+    _LIBCPP_NORETURN _LIBCPP_HIDE_FROM_ABI
+    void __throw_length_error() const {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        __vector_base_common<true>::__throw_length_error();
+#else
+        _VSTD::abort();
+#endif
+    }
+
+    _LIBCPP_NORETURN _LIBCPP_HIDE_FROM_ABI
+    void __throw_out_of_range() const {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        __vector_base_common<true>::__throw_out_of_range();
+#else
+        _VSTD::abort();
+#endif
+    }
+
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __vector_base& __c, true_type)
+        {
+            if (__alloc() != __c.__alloc())
+            {
+                clear();
+                __alloc_traits::deallocate(__alloc(), __begin_, capacity());
+                __begin_ = __end_ = __end_cap() = nullptr;
+            }
+            __alloc() = __c.__alloc();
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const __vector_base&, false_type)
+        {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__vector_base& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
+        {
+            __alloc() = _VSTD::move(__c.__alloc());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(__vector_base&, false_type)
+        _NOEXCEPT
+        {}
+};
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+__vector_base<_Tp, _Allocator>::__destruct_at_end(pointer __new_last) _NOEXCEPT
+{
+    pointer __soon_to_be_end = __end_;
+    while (__new_last != __soon_to_be_end)
+        __alloc_traits::destroy(__alloc(), _VSTD::__to_address(--__soon_to_be_end));
+    __end_ = __new_last;
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+__vector_base<_Tp, _Allocator>::__vector_base()
+        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
+    : __begin_(nullptr),
+      __end_(nullptr),
+      __end_cap_(nullptr, __default_init_tag())
+{
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+__vector_base<_Tp, _Allocator>::__vector_base(const allocator_type& __a)
+    : __begin_(nullptr),
+      __end_(nullptr),
+      __end_cap_(nullptr, __a)
+{
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+__vector_base<_Tp, _Allocator>::__vector_base(allocator_type&& __a) _NOEXCEPT
+    : __begin_(nullptr),
+      __end_(nullptr),
+      __end_cap_(nullptr, _VSTD::move(__a)) {}
+#endif
+
+template <class _Tp, class _Allocator>
+__vector_base<_Tp, _Allocator>::~__vector_base()
+{
+    if (__begin_ != nullptr)
+    {
+        clear();
+        __alloc_traits::deallocate(__alloc(), __begin_, capacity());
+    }
+}
+
+template <class _Tp, class _Allocator /* = allocator<_Tp> */>
+class _LIBCPP_TEMPLATE_VIS vector
+    : private __vector_base<_Tp, _Allocator>
+{
+private:
+    typedef __vector_base<_Tp, _Allocator>           __base;
+    typedef allocator<_Tp>                           __default_allocator_type;
+public:
+    typedef vector                                   __self;
+    typedef _Tp                                      value_type;
+    typedef _Allocator                               allocator_type;
+    typedef typename __base::__alloc_traits          __alloc_traits;
+    typedef typename __base::reference               reference;
+    typedef typename __base::const_reference         const_reference;
+    typedef typename __base::size_type               size_type;
+    typedef typename __base::difference_type         difference_type;
+    typedef typename __base::pointer                 pointer;
+    typedef typename __base::const_pointer           const_pointer;
+#if _YNDX_LIBCPP_MAKE_VECTOR_ITERATOR_POINTERS == 1
+    typedef typename __base::pointer                 iterator;
+    typedef typename __base::const_pointer           const_iterator;
+#else
+    typedef __wrap_iter<pointer>                     iterator;
+    typedef __wrap_iter<const_pointer>               const_iterator;
+#endif
+    typedef _VSTD::reverse_iterator<iterator>         reverse_iterator;
+    typedef _VSTD::reverse_iterator<const_iterator>   const_reverse_iterator;
+
+    static_assert((is_same<typename allocator_type::value_type, value_type>::value),
+                  "Allocator::value_type must be same type as value_type");
+
+    _LIBCPP_INLINE_VISIBILITY
+    vector() _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
+        {
+#if _LIBCPP_DEBUG_LEVEL == 2
+            __get_db()->__insert_c(this);
+#endif
+        }
+    _LIBCPP_INLINE_VISIBILITY explicit vector(const allocator_type& __a)
+#if _LIBCPP_STD_VER <= 14
+        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
+#else
+        _NOEXCEPT
+#endif
+        : __base(__a)
+    {
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__insert_c(this);
+#endif
+    }
+    explicit vector(size_type __n);
+#if _LIBCPP_STD_VER > 11
+    explicit vector(size_type __n, const allocator_type& __a);
+#endif
+    vector(size_type __n, const value_type& __x);
+    vector(size_type __n, const value_type& __x, const allocator_type& __a);
+    template <class _InputIterator>
+        vector(_InputIterator __first,
+               typename enable_if<__is_cpp17_input_iterator  <_InputIterator>::value &&
+                                 !__is_cpp17_forward_iterator<_InputIterator>::value &&
+                                 is_constructible<
+                                    value_type,
+                                    typename iterator_traits<_InputIterator>::reference>::value,
+                                 _InputIterator>::type __last);
+    template <class _InputIterator>
+        vector(_InputIterator __first, _InputIterator __last, const allocator_type& __a,
+               typename enable_if<__is_cpp17_input_iterator  <_InputIterator>::value &&
+                                 !__is_cpp17_forward_iterator<_InputIterator>::value &&
+                                 is_constructible<
+                                    value_type,
+                                    typename iterator_traits<_InputIterator>::reference>::value>::type* = 0);
+    template <class _ForwardIterator>
+        vector(_ForwardIterator __first,
+               typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value &&
+                                 is_constructible<
+                                    value_type,
+                                    typename iterator_traits<_ForwardIterator>::reference>::value,
+                                 _ForwardIterator>::type __last);
+    template <class _ForwardIterator>
+        vector(_ForwardIterator __first, _ForwardIterator __last, const allocator_type& __a,
+               typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value &&
+                                 is_constructible<
+                                    value_type,
+                                    typename iterator_traits<_ForwardIterator>::reference>::value>::type* = 0);
+
+    _LIBCPP_INLINE_VISIBILITY
+    ~vector()
+    {
+        __annotate_delete();
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->__erase_c(this);
+#endif
+    }
+
+    vector(const vector& __x);
+    vector(const vector& __x, const __identity_t<allocator_type>& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    vector& operator=(const vector& __x);
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    vector(initializer_list<value_type> __il);
+
+    _LIBCPP_INLINE_VISIBILITY
+    vector(initializer_list<value_type> __il, const allocator_type& __a);
+
+    _LIBCPP_INLINE_VISIBILITY
+    vector(vector&& __x)
+#if _LIBCPP_STD_VER > 14
+        _NOEXCEPT;
+#else
+        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value);
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    vector(vector&& __x, const __identity_t<allocator_type>& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    vector& operator=(vector&& __x)
+        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value));
+
+    _LIBCPP_INLINE_VISIBILITY
+    vector& operator=(initializer_list<value_type> __il)
+        {assign(__il.begin(), __il.end()); return *this;}
+
+#endif // !_LIBCPP_CXX03_LANG
+
+    template <class _InputIterator>
+        typename enable_if
+        <
+             __is_cpp17_input_iterator  <_InputIterator>::value &&
+            !__is_cpp17_forward_iterator<_InputIterator>::value &&
+            is_constructible<
+                 value_type,
+                 typename iterator_traits<_InputIterator>::reference>::value,
+            void
+        >::type
+        assign(_InputIterator __first, _InputIterator __last);
+    template <class _ForwardIterator>
+        typename enable_if
+        <
+            __is_cpp17_forward_iterator<_ForwardIterator>::value &&
+            is_constructible<
+                 value_type,
+                 typename iterator_traits<_ForwardIterator>::reference>::value,
+            void
+        >::type
+        assign(_ForwardIterator __first, _ForwardIterator __last);
+
+    void assign(size_type __n, const_reference __u);
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void assign(initializer_list<value_type> __il)
+        {assign(__il.begin(), __il.end());}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY
+    allocator_type get_allocator() const _NOEXCEPT
+        {return this->__alloc();}
+
+    _LIBCPP_INLINE_VISIBILITY iterator               begin() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY const_iterator         begin()   const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY iterator               end() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY const_iterator         end()     const _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    reverse_iterator       rbegin() _NOEXCEPT
+        {return       reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rbegin()  const _NOEXCEPT
+        {return const_reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    reverse_iterator       rend() _NOEXCEPT
+        {return       reverse_iterator(begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rend()    const _NOEXCEPT
+        {return const_reverse_iterator(begin());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator         cbegin()  const _NOEXCEPT
+        {return begin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator         cend()    const _NOEXCEPT
+        {return end();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crbegin() const _NOEXCEPT
+        {return rbegin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crend()   const _NOEXCEPT
+        {return rend();}
+
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT
+        {return static_cast<size_type>(this->__end_ - this->__begin_);}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type capacity() const _NOEXCEPT
+        {return __base::capacity();}
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT
+        {return this->__begin_ == this->__end_;}
+    size_type max_size() const _NOEXCEPT;
+    void reserve(size_type __n);
+    void shrink_to_fit() _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY reference       operator[](size_type __n) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY const_reference operator[](size_type __n) const _NOEXCEPT;
+    reference       at(size_type __n);
+    const_reference at(size_type __n) const;
+
+    _LIBCPP_INLINE_VISIBILITY reference       front() _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(!empty(), "front() called on an empty vector");
+        return *this->__begin_;
+    }
+    _LIBCPP_INLINE_VISIBILITY const_reference front() const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(!empty(), "front() called on an empty vector");
+        return *this->__begin_;
+    }
+    _LIBCPP_INLINE_VISIBILITY reference       back() _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(!empty(), "back() called on an empty vector");
+        return *(this->__end_ - 1);
+    }
+    _LIBCPP_INLINE_VISIBILITY const_reference back()  const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(!empty(), "back() called on an empty vector");
+        return *(this->__end_ - 1);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    value_type*       data() _NOEXCEPT
+        {return _VSTD::__to_address(this->__begin_);}
+    _LIBCPP_INLINE_VISIBILITY
+    const value_type* data() const _NOEXCEPT
+        {return _VSTD::__to_address(this->__begin_);}
+
+#ifdef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void __emplace_back(const value_type& __x) { push_back(__x); }
+#else
+    template <class _Arg>
+    _LIBCPP_INLINE_VISIBILITY
+    void __emplace_back(_Arg&& __arg) {
+      emplace_back(_VSTD::forward<_Arg>(__arg));
+    }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY void push_back(const_reference __x);
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY void push_back(value_type&& __x);
+
+    template <class... _Args>
+        _LIBCPP_INLINE_VISIBILITY
+#if _LIBCPP_STD_VER > 14
+        reference emplace_back(_Args&&... __args);
+#else
+        void      emplace_back(_Args&&... __args);
+#endif
+#endif // !_LIBCPP_CXX03_LANG
+
+    _LIBCPP_INLINE_VISIBILITY
+    void pop_back();
+
+    iterator insert(const_iterator __position, const_reference __x);
+
+#ifndef _LIBCPP_CXX03_LANG
+    iterator insert(const_iterator __position, value_type&& __x);
+    template <class... _Args>
+        iterator emplace(const_iterator __position, _Args&&... __args);
+#endif // !_LIBCPP_CXX03_LANG
+
+    iterator insert(const_iterator __position, size_type __n, const_reference __x);
+    template <class _InputIterator>
+        typename enable_if
+        <
+             __is_cpp17_input_iterator  <_InputIterator>::value &&
+            !__is_cpp17_forward_iterator<_InputIterator>::value &&
+            is_constructible<
+                 value_type,
+                 typename iterator_traits<_InputIterator>::reference>::value,
+            iterator
+        >::type
+        insert(const_iterator __position, _InputIterator __first, _InputIterator __last);
+    template <class _ForwardIterator>
+        typename enable_if
+        <
+            __is_cpp17_forward_iterator<_ForwardIterator>::value &&
+            is_constructible<
+                 value_type,
+                 typename iterator_traits<_ForwardIterator>::reference>::value,
+            iterator
+        >::type
+        insert(const_iterator __position, _ForwardIterator __first, _ForwardIterator __last);
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __position, initializer_list<value_type> __il)
+        {return insert(__position, __il.begin(), __il.end());}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY iterator erase(const_iterator __position);
+    iterator erase(const_iterator __first, const_iterator __last);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT
+    {
+        size_type __old_size = size();
+        __base::clear();
+        __annotate_shrink(__old_size);
+        __invalidate_all_iterators();
+    }
+
+#if _YNDX_LIBCXX_ENABLE_VECTOR_POD_RESIZE_UNINITIALIZED
+    void resize_uninitialized(size_type __sz);
+#endif
+
+    void resize(size_type __sz);
+    void resize(size_type __sz, const_reference __x);
+
+    void swap(vector&)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT;
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<allocator_type>::value);
+#endif
+
+    bool __invariants() const;
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+    bool __dereferenceable(const const_iterator* __i) const;
+    bool __decrementable(const const_iterator* __i) const;
+    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
+    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+private:
+    _LIBCPP_INLINE_VISIBILITY void __invalidate_all_iterators();
+    _LIBCPP_INLINE_VISIBILITY void __invalidate_iterators_past(pointer __new_last);
+    void __vallocate(size_type __n);
+    void __vdeallocate() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY size_type __recommend(size_type __new_size) const;
+    void __construct_at_end(size_type __n);
+    _LIBCPP_INLINE_VISIBILITY
+    void __construct_at_end(size_type __n, const_reference __x);
+    template <class _ForwardIterator>
+        typename enable_if
+        <
+            __is_cpp17_forward_iterator<_ForwardIterator>::value,
+            void
+        >::type
+        __construct_at_end(_ForwardIterator __first, _ForwardIterator __last, size_type __n);
+    void __append_uninitialized(size_type __n);
+    void __append(size_type __n);
+    void __append(size_type __n, const_reference __x);
+    _LIBCPP_INLINE_VISIBILITY
+    iterator       __make_iter(pointer __p) _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator __make_iter(const_pointer __p) const _NOEXCEPT;
+    void __swap_out_circular_buffer(__split_buffer<value_type, allocator_type&>& __v);
+    pointer __swap_out_circular_buffer(__split_buffer<value_type, allocator_type&>& __v, pointer __p);
+    void __move_range(pointer __from_s, pointer __from_e, pointer __to);
+    void __move_assign(vector& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value);
+    void __move_assign(vector& __c, false_type)
+        _NOEXCEPT_(__alloc_traits::is_always_equal::value);
+    _LIBCPP_INLINE_VISIBILITY
+    void __destruct_at_end(pointer __new_last) _NOEXCEPT
+    {
+        __invalidate_iterators_past(__new_last);
+        size_type __old_size = size();
+        __base::__destruct_at_end(__new_last);
+        __annotate_shrink(__old_size);
+    }
+
+// Disable double inline warning.
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4141 )
+#endif
+#ifndef _LIBCPP_CXX03_LANG
+    template <class _Up>
+    _LIBCPP_INLINE_VISIBILITY
+    inline void __push_back_slow_path(_Up&& __x);
+
+    template <class... _Args>
+    _LIBCPP_INLINE_VISIBILITY
+    inline void __emplace_back_slow_path(_Args&&... __args);
+#else
+    template <class _Up>
+    _LIBCPP_INLINE_VISIBILITY
+    inline void __push_back_slow_path(_Up& __x);
+#endif
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+    // The following functions are no-ops outside of AddressSanitizer mode.
+    // We call annotatations only for the default Allocator because other allocators
+    // may not meet the AddressSanitizer alignment constraints.
+    // See the documentation for __sanitizer_annotate_contiguous_container for more details.
+#ifndef _LIBCPP_HAS_NO_ASAN
+    void __annotate_contiguous_container(const void *__beg, const void *__end,
+                                         const void *__old_mid,
+                                         const void *__new_mid) const
+    {
+
+      if (__beg && is_same<allocator_type, __default_allocator_type>::value)
+        __sanitizer_annotate_contiguous_container(__beg, __end, __old_mid, __new_mid);
+    }
+#else
+    _LIBCPP_INLINE_VISIBILITY
+    void __annotate_contiguous_container(const void*, const void*, const void*,
+                                         const void*) const _NOEXCEPT {}
+#endif
+    _LIBCPP_INLINE_VISIBILITY
+    void __annotate_new(size_type __current_size) const _NOEXCEPT {
+      __annotate_contiguous_container(data(), data() + capacity(),
+                                      data() + capacity(), data() + __current_size);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __annotate_delete() const _NOEXCEPT {
+      __annotate_contiguous_container(data(), data() + capacity(),
+                                      data() + size(), data() + capacity());
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __annotate_increase(size_type __n) const _NOEXCEPT
+    {
+      __annotate_contiguous_container(data(), data() + capacity(),
+                                      data() + size(), data() + size() + __n);
+    }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __annotate_shrink(size_type __old_size) const _NOEXCEPT
+    {
+      __annotate_contiguous_container(data(), data() + capacity(),
+                                      data() + __old_size, data() + size());
+    }
+
+  struct _ConstructTransaction {
+    explicit _ConstructTransaction(vector &__v, size_type __n)
+      : __v_(__v),  __pos_(__v.__end_), __new_end_(__v.__end_ + __n) {
+#ifndef _LIBCPP_HAS_NO_ASAN
+      __v_.__annotate_increase(__n);
+#endif
+    }
+    ~_ConstructTransaction() {
+      __v_.__end_ = __pos_;
+#ifndef _LIBCPP_HAS_NO_ASAN
+      if (__pos_ != __new_end_) {
+        __v_.__annotate_shrink(__new_end_ - __v_.__begin_);
+      }
+#endif
+    }
+
+    vector &__v_;
+    pointer __pos_;
+    const_pointer const __new_end_;
+
+  private:
+    _ConstructTransaction(_ConstructTransaction const&) = delete;
+    _ConstructTransaction& operator=(_ConstructTransaction const&) = delete;
+  };
+
+  template <class ..._Args>
+  _LIBCPP_INLINE_VISIBILITY
+  void __construct_one_at_end(_Args&& ...__args) {
+    _ConstructTransaction __tx(*this, 1);
+    __alloc_traits::construct(this->__alloc(), _VSTD::__to_address(__tx.__pos_),
+        _VSTD::forward<_Args>(__args)...);
+    ++__tx.__pos_;
+  }
+};
+
+#if _LIBCPP_STD_VER >= 17
+template<class _InputIterator,
+         class _Alloc = allocator<__iter_value_type<_InputIterator>>,
+         class = enable_if_t<__is_allocator<_Alloc>::value>
+         >
+vector(_InputIterator, _InputIterator)
+  -> vector<__iter_value_type<_InputIterator>, _Alloc>;
+
+template<class _InputIterator,
+         class _Alloc,
+         class = enable_if_t<__is_allocator<_Alloc>::value>
+         >
+vector(_InputIterator, _InputIterator, _Alloc)
+  -> vector<__iter_value_type<_InputIterator>, _Alloc>;
+#endif
+
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::__swap_out_circular_buffer(__split_buffer<value_type, allocator_type&>& __v)
+{
+
+    __annotate_delete();
+    _VSTD::__construct_backward_with_exception_guarantees(this->__alloc(), this->__begin_, this->__end_, __v.__begin_);
+    _VSTD::swap(this->__begin_, __v.__begin_);
+    _VSTD::swap(this->__end_, __v.__end_);
+    _VSTD::swap(this->__end_cap(), __v.__end_cap());
+    __v.__first_ = __v.__begin_;
+    __annotate_new(size());
+    __invalidate_all_iterators();
+}
+
+template <class _Tp, class _Allocator>
+typename vector<_Tp, _Allocator>::pointer
+vector<_Tp, _Allocator>::__swap_out_circular_buffer(__split_buffer<value_type, allocator_type&>& __v, pointer __p)
+{
+    __annotate_delete();
+    pointer __r = __v.__begin_;
+    _VSTD::__construct_backward_with_exception_guarantees(this->__alloc(), this->__begin_, __p, __v.__begin_);
+    _VSTD::__construct_forward_with_exception_guarantees(this->__alloc(), __p, this->__end_, __v.__end_);
+    _VSTD::swap(this->__begin_, __v.__begin_);
+    _VSTD::swap(this->__end_, __v.__end_);
+    _VSTD::swap(this->__end_cap(), __v.__end_cap());
+    __v.__first_ = __v.__begin_;
+    __annotate_new(size());
+    __invalidate_all_iterators();
+    return __r;
+}
+
+//  Allocate space for __n objects
+//  throws length_error if __n > max_size()
+//  throws (probably bad_alloc) if memory run out
+//  Precondition:  __begin_ == __end_ == __end_cap() == 0
+//  Precondition:  __n > 0
+//  Postcondition:  capacity() == __n
+//  Postcondition:  size() == 0
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::__vallocate(size_type __n)
+{
+    if (__n > max_size())
+        this->__throw_length_error();
+    this->__begin_ = this->__end_ = __alloc_traits::allocate(this->__alloc(), __n);
+    this->__end_cap() = this->__begin_ + __n;
+    __annotate_new(0);
+}
+
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::__vdeallocate() _NOEXCEPT
+{
+    if (this->__begin_ != nullptr)
+    {
+        clear();
+        __alloc_traits::deallocate(this->__alloc(), this->__begin_, capacity());
+        this->__begin_ = this->__end_ = this->__end_cap() = nullptr;
+    }
+}
+
+template <class _Tp, class _Allocator>
+typename vector<_Tp, _Allocator>::size_type
+vector<_Tp, _Allocator>::max_size() const _NOEXCEPT
+{
+    return _VSTD::min<size_type>(__alloc_traits::max_size(this->__alloc()),
+                                 numeric_limits<difference_type>::max());
+}
+
+//  Precondition:  __new_size > capacity()
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename vector<_Tp, _Allocator>::size_type
+vector<_Tp, _Allocator>::__recommend(size_type __new_size) const
+{
+    const size_type __ms = max_size();
+    if (__new_size > __ms)
+        this->__throw_length_error();
+    const size_type __cap = capacity();
+    if (__cap >= __ms / 2)
+        return __ms;
+    return _VSTD::max<size_type>(2 * __cap, __new_size);
+}
+
+//  Default constructs __n objects starting at __end_
+//  throws if construction throws
+//  Precondition:  __n > 0
+//  Precondition:  size() + __n <= capacity()
+//  Postcondition:  size() == size() + __n
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::__construct_at_end(size_type __n)
+{
+    _ConstructTransaction __tx(*this, __n);
+    const_pointer __new_end = __tx.__new_end_;
+    for (pointer __pos = __tx.__pos_; __pos != __new_end; __tx.__pos_ = ++__pos) {
+        __alloc_traits::construct(this->__alloc(), _VSTD::__to_address(__pos));
+    }
+}
+
+//  Copy constructs __n objects starting at __end_ from __x
+//  throws if construction throws
+//  Precondition:  __n > 0
+//  Precondition:  size() + __n <= capacity()
+//  Postcondition:  size() == old size() + __n
+//  Postcondition:  [i] == __x for all i in [size() - __n, __n)
+template <class _Tp, class _Allocator>
+inline
+void
+vector<_Tp, _Allocator>::__construct_at_end(size_type __n, const_reference __x)
+{
+    _ConstructTransaction __tx(*this, __n);
+    const_pointer __new_end = __tx.__new_end_;
+    for (pointer __pos = __tx.__pos_; __pos != __new_end; __tx.__pos_ = ++__pos) {
+        __alloc_traits::construct(this->__alloc(), _VSTD::__to_address(__pos), __x);
+    }
+}
+
+template <class _Tp, class _Allocator>
+template <class _ForwardIterator>
+typename enable_if
+<
+    __is_cpp17_forward_iterator<_ForwardIterator>::value,
+    void
+>::type
+vector<_Tp, _Allocator>::__construct_at_end(_ForwardIterator __first, _ForwardIterator __last, size_type __n)
+{
+    _ConstructTransaction __tx(*this, __n);
+    _VSTD::__construct_range_forward(this->__alloc(), __first, __last, __tx.__pos_);
+}
+
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::__append_uninitialized(size_type __n)
+{
+    if (static_cast<size_type>(this->__end_cap() - this->__end_) >= __n) {
+        __annotate_increase(__n);
+        this->__end_ += __n;
+    }
+    else
+    {
+        allocator_type& __a = this->__alloc();
+        __split_buffer<value_type, allocator_type&> __v(__recommend(size() + __n), size(), __a);
+        __v.__uninitialized_at_end(__n);
+        __swap_out_circular_buffer(__v);
+    }
+}
+
+//  Default constructs __n objects starting at __end_
+//  throws if construction throws
+//  Postcondition:  size() == size() + __n
+//  Exception safety: strong.
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::__append(size_type __n)
+{
+    if (static_cast<size_type>(this->__end_cap() - this->__end_) >= __n)
+        this->__construct_at_end(__n);
+    else
+    {
+        allocator_type& __a = this->__alloc();
+        __split_buffer<value_type, allocator_type&> __v(__recommend(size() + __n), size(), __a);
+        __v.__construct_at_end(__n);
+        __swap_out_circular_buffer(__v);
+    }
+}
+
+//  Default constructs __n objects starting at __end_
+//  throws if construction throws
+//  Postcondition:  size() == size() + __n
+//  Exception safety: strong.
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::__append(size_type __n, const_reference __x)
+{
+    if (static_cast<size_type>(this->__end_cap() - this->__end_) >= __n)
+        this->__construct_at_end(__n, __x);
+    else
+    {
+        allocator_type& __a = this->__alloc();
+        __split_buffer<value_type, allocator_type&> __v(__recommend(size() + __n), size(), __a);
+        __v.__construct_at_end(__n, __x);
+        __swap_out_circular_buffer(__v);
+    }
+}
+
+template <class _Tp, class _Allocator>
+vector<_Tp, _Allocator>::vector(size_type __n)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__n);
+    }
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _Tp, class _Allocator>
+vector<_Tp, _Allocator>::vector(size_type __n, const allocator_type& __a)
+    : __base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__n);
+    }
+}
+#endif
+
+template <class _Tp, class _Allocator>
+vector<_Tp, _Allocator>::vector(size_type __n, const value_type& __x)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__n, __x);
+    }
+}
+
+template <class _Tp, class _Allocator>
+vector<_Tp, _Allocator>::vector(size_type __n, const value_type& __x, const allocator_type& __a)
+    : __base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__n, __x);
+    }
+}
+
+template <class _Tp, class _Allocator>
+template <class _InputIterator>
+vector<_Tp, _Allocator>::vector(_InputIterator __first,
+       typename enable_if<__is_cpp17_input_iterator  <_InputIterator>::value &&
+                         !__is_cpp17_forward_iterator<_InputIterator>::value &&
+                         is_constructible<
+                            value_type,
+                            typename iterator_traits<_InputIterator>::reference>::value,
+                          _InputIterator>::type __last)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __first != __last; ++__first)
+        __emplace_back(*__first);
+}
+
+template <class _Tp, class _Allocator>
+template <class _InputIterator>
+vector<_Tp, _Allocator>::vector(_InputIterator __first, _InputIterator __last, const allocator_type& __a,
+       typename enable_if<__is_cpp17_input_iterator  <_InputIterator>::value &&
+                         !__is_cpp17_forward_iterator<_InputIterator>::value &&
+                         is_constructible<
+                            value_type,
+                            typename iterator_traits<_InputIterator>::reference>::value>::type*)
+    : __base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    for (; __first != __last; ++__first)
+        __emplace_back(*__first);
+}
+
+template <class _Tp, class _Allocator>
+template <class _ForwardIterator>
+vector<_Tp, _Allocator>::vector(_ForwardIterator __first,
+                                typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value &&
+                                is_constructible<
+                                   value_type,
+                                   typename iterator_traits<_ForwardIterator>::reference>::value,
+                                                   _ForwardIterator>::type __last)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__first, __last, __n);
+    }
+}
+
+template <class _Tp, class _Allocator>
+template <class _ForwardIterator>
+vector<_Tp, _Allocator>::vector(_ForwardIterator __first, _ForwardIterator __last, const allocator_type& __a,
+                                typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value &&
+                                is_constructible<
+                                   value_type,
+                                   typename iterator_traits<_ForwardIterator>::reference>::value>::type*)
+    : __base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__first, __last, __n);
+    }
+}
+
+template <class _Tp, class _Allocator>
+vector<_Tp, _Allocator>::vector(const vector& __x)
+    : __base(__alloc_traits::select_on_container_copy_construction(__x.__alloc()))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    size_type __n = __x.size();
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__x.__begin_, __x.__end_, __n);
+    }
+}
+
+template <class _Tp, class _Allocator>
+vector<_Tp, _Allocator>::vector(const vector& __x, const __identity_t<allocator_type>& __a)
+    : __base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    size_type __n = __x.size();
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__x.__begin_, __x.__end_, __n);
+    }
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+vector<_Tp, _Allocator>::vector(vector&& __x)
+#if _LIBCPP_STD_VER > 14
+        _NOEXCEPT
+#else
+        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
+#endif
+    : __base(_VSTD::move(__x.__alloc()))
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+    __get_db()->swap(this, &__x);
+#endif
+    this->__begin_ = __x.__begin_;
+    this->__end_ = __x.__end_;
+    this->__end_cap() = __x.__end_cap();
+    __x.__begin_ = __x.__end_ = __x.__end_cap() = nullptr;
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+vector<_Tp, _Allocator>::vector(vector&& __x, const __identity_t<allocator_type>& __a)
+    : __base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    if (__a == __x.__alloc())
+    {
+        this->__begin_ = __x.__begin_;
+        this->__end_ = __x.__end_;
+        this->__end_cap() = __x.__end_cap();
+        __x.__begin_ = __x.__end_ = __x.__end_cap() = nullptr;
+#if _LIBCPP_DEBUG_LEVEL == 2
+        __get_db()->swap(this, &__x);
+#endif
+    }
+    else
+    {
+        typedef move_iterator<iterator> _Ip;
+        assign(_Ip(__x.begin()), _Ip(__x.end()));
+    }
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+vector<_Tp, _Allocator>::vector(initializer_list<value_type> __il)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    if (__il.size() > 0)
+    {
+        __vallocate(__il.size());
+        __construct_at_end(__il.begin(), __il.end(), __il.size());
+    }
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+vector<_Tp, _Allocator>::vector(initializer_list<value_type> __il, const allocator_type& __a)
+    : __base(__a)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__insert_c(this);
+#endif
+    if (__il.size() > 0)
+    {
+        __vallocate(__il.size());
+        __construct_at_end(__il.begin(), __il.end(), __il.size());
+    }
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+vector<_Tp, _Allocator>&
+vector<_Tp, _Allocator>::operator=(vector&& __x)
+    _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
+{
+    __move_assign(__x, integral_constant<bool,
+          __alloc_traits::propagate_on_container_move_assignment::value>());
+    return *this;
+}
+
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::__move_assign(vector& __c, false_type)
+    _NOEXCEPT_(__alloc_traits::is_always_equal::value)
+{
+    if (__base::__alloc() != __c.__alloc())
+    {
+        typedef move_iterator<iterator> _Ip;
+        assign(_Ip(__c.begin()), _Ip(__c.end()));
+    }
+    else
+        __move_assign(__c, true_type());
+}
+
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::__move_assign(vector& __c, true_type)
+    _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
+{
+    __vdeallocate();
+    __base::__move_assign_alloc(__c); // this can throw
+    this->__begin_ = __c.__begin_;
+    this->__end_ = __c.__end_;
+    this->__end_cap() = __c.__end_cap();
+    __c.__begin_ = __c.__end_ = __c.__end_cap() = nullptr;
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->swap(this, &__c);
+#endif
+}
+
+#endif // !_LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+vector<_Tp, _Allocator>&
+vector<_Tp, _Allocator>::operator=(const vector& __x)
+{
+    if (this != _VSTD::addressof(__x))
+    {
+        __base::__copy_assign_alloc(__x);
+        assign(__x.__begin_, __x.__end_);
+    }
+    return *this;
+}
+
+template <class _Tp, class _Allocator>
+template <class _InputIterator>
+typename enable_if
+<
+     __is_cpp17_input_iterator  <_InputIterator>::value &&
+    !__is_cpp17_forward_iterator<_InputIterator>::value &&
+    is_constructible<
+       _Tp,
+       typename iterator_traits<_InputIterator>::reference>::value,
+    void
+>::type
+vector<_Tp, _Allocator>::assign(_InputIterator __first, _InputIterator __last)
+{
+    clear();
+    for (; __first != __last; ++__first)
+        __emplace_back(*__first);
+}
+
+template <class _Tp, class _Allocator>
+template <class _ForwardIterator>
+typename enable_if
+<
+    __is_cpp17_forward_iterator<_ForwardIterator>::value &&
+    is_constructible<
+       _Tp,
+       typename iterator_traits<_ForwardIterator>::reference>::value,
+    void
+>::type
+vector<_Tp, _Allocator>::assign(_ForwardIterator __first, _ForwardIterator __last)
+{
+    size_type __new_size = static_cast<size_type>(_VSTD::distance(__first, __last));
+    if (__new_size <= capacity())
+    {
+        _ForwardIterator __mid = __last;
+        bool __growing = false;
+        if (__new_size > size())
+        {
+            __growing = true;
+            __mid =  __first;
+            _VSTD::advance(__mid, size());
+        }
+        pointer __m = _VSTD::copy(__first, __mid, this->__begin_);
+        if (__growing)
+            __construct_at_end(__mid, __last, __new_size - size());
+        else
+            this->__destruct_at_end(__m);
+    }
+    else
+    {
+        __vdeallocate();
+        __vallocate(__recommend(__new_size));
+        __construct_at_end(__first, __last, __new_size);
+    }
+    __invalidate_all_iterators();
+}
+
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::assign(size_type __n, const_reference __u)
+{
+    if (__n <= capacity())
+    {
+        size_type __s = size();
+        _VSTD::fill_n(this->__begin_, _VSTD::min(__n, __s), __u);
+        if (__n > __s)
+            __construct_at_end(__n - __s, __u);
+        else
+            this->__destruct_at_end(this->__begin_ + __n);
+    }
+    else
+    {
+        __vdeallocate();
+        __vallocate(__recommend(static_cast<size_type>(__n)));
+        __construct_at_end(__n, __u);
+    }
+    __invalidate_all_iterators();
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename vector<_Tp, _Allocator>::iterator
+vector<_Tp, _Allocator>::__make_iter(pointer __p) _NOEXCEPT
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return iterator(this, __p);
+#else
+    return iterator(__p);
+#endif
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename vector<_Tp, _Allocator>::const_iterator
+vector<_Tp, _Allocator>::__make_iter(const_pointer __p) const _NOEXCEPT
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    return const_iterator(this, __p);
+#else
+    return const_iterator(__p);
+#endif
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename vector<_Tp, _Allocator>::iterator
+vector<_Tp, _Allocator>::begin() _NOEXCEPT
+{
+    return __make_iter(this->__begin_);
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename vector<_Tp, _Allocator>::const_iterator
+vector<_Tp, _Allocator>::begin() const _NOEXCEPT
+{
+    return __make_iter(this->__begin_);
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename vector<_Tp, _Allocator>::iterator
+vector<_Tp, _Allocator>::end() _NOEXCEPT
+{
+    return __make_iter(this->__end_);
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename vector<_Tp, _Allocator>::const_iterator
+vector<_Tp, _Allocator>::end() const _NOEXCEPT
+{
+    return __make_iter(this->__end_);
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename vector<_Tp, _Allocator>::reference
+vector<_Tp, _Allocator>::operator[](size_type __n) _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__n < size(), "vector[] index out of bounds");
+    return this->__begin_[__n];
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename vector<_Tp, _Allocator>::const_reference
+vector<_Tp, _Allocator>::operator[](size_type __n) const _NOEXCEPT
+{
+    _LIBCPP_ASSERT(__n < size(), "vector[] index out of bounds");
+    return this->__begin_[__n];
+}
+
+template <class _Tp, class _Allocator>
+typename vector<_Tp, _Allocator>::reference
+vector<_Tp, _Allocator>::at(size_type __n)
+{
+    if (__n >= size())
+        this->__throw_out_of_range();
+    return this->__begin_[__n];
+}
+
+template <class _Tp, class _Allocator>
+typename vector<_Tp, _Allocator>::const_reference
+vector<_Tp, _Allocator>::at(size_type __n) const
+{
+    if (__n >= size())
+        this->__throw_out_of_range();
+    return this->__begin_[__n];
+}
+
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::reserve(size_type __n)
+{
+    if (__n > capacity())
+    {
+        allocator_type& __a = this->__alloc();
+        __split_buffer<value_type, allocator_type&> __v(__n, size(), __a);
+        __swap_out_circular_buffer(__v);
+    }
+}
+
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::shrink_to_fit() _NOEXCEPT
+{
+    if (capacity() > size())
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            allocator_type& __a = this->__alloc();
+            __split_buffer<value_type, allocator_type&> __v(size(), size(), __a);
+            __swap_out_circular_buffer(__v);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+}
+
+template <class _Tp, class _Allocator>
+template <class _Up>
+void
+#ifndef _LIBCPP_CXX03_LANG
+vector<_Tp, _Allocator>::__push_back_slow_path(_Up&& __x)
+#else
+vector<_Tp, _Allocator>::__push_back_slow_path(_Up& __x)
+#endif
+{
+    allocator_type& __a = this->__alloc();
+    __split_buffer<value_type, allocator_type&> __v(__recommend(size() + 1), size(), __a);
+    // __v.push_back(_VSTD::forward<_Up>(__x));
+    __alloc_traits::construct(__a, _VSTD::__to_address(__v.__end_), _VSTD::forward<_Up>(__x));
+    __v.__end_++;
+    __swap_out_circular_buffer(__v);
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+vector<_Tp, _Allocator>::push_back(const_reference __x)
+{
+    if (this->__end_ != this->__end_cap())
+    {
+        __construct_one_at_end(__x);
+    }
+    else
+        __push_back_slow_path(__x);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+vector<_Tp, _Allocator>::push_back(value_type&& __x)
+{
+    if (this->__end_ < this->__end_cap())
+    {
+        __construct_one_at_end(_VSTD::move(__x));
+    }
+    else
+        __push_back_slow_path(_VSTD::move(__x));
+}
+
+template <class _Tp, class _Allocator>
+template <class... _Args>
+void
+vector<_Tp, _Allocator>::__emplace_back_slow_path(_Args&&... __args)
+{
+    allocator_type& __a = this->__alloc();
+    __split_buffer<value_type, allocator_type&> __v(__recommend(size() + 1), size(), __a);
+//    __v.emplace_back(_VSTD::forward<_Args>(__args)...);
+    __alloc_traits::construct(__a, _VSTD::__to_address(__v.__end_), _VSTD::forward<_Args>(__args)...);
+    __v.__end_++;
+    __swap_out_circular_buffer(__v);
+}
+
+template <class _Tp, class _Allocator>
+template <class... _Args>
+inline
+#if _LIBCPP_STD_VER > 14
+typename vector<_Tp, _Allocator>::reference
+#else
+void
+#endif
+vector<_Tp, _Allocator>::emplace_back(_Args&&... __args)
+{
+    if (this->__end_ < this->__end_cap())
+    {
+        __construct_one_at_end(_VSTD::forward<_Args>(__args)...);
+    }
+    else
+        __emplace_back_slow_path(_VSTD::forward<_Args>(__args)...);
+#if _LIBCPP_STD_VER > 14
+    return this->back();
+#endif
+}
+
+#endif // !_LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Allocator>
+inline
+void
+vector<_Tp, _Allocator>::pop_back()
+{
+    _LIBCPP_ASSERT(!empty(), "vector::pop_back called on an empty vector");
+    this->__destruct_at_end(this->__end_ - 1);
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename vector<_Tp, _Allocator>::iterator
+vector<_Tp, _Allocator>::erase(const_iterator __position)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__position) == this,
+        "vector::erase(iterator) called with an iterator not"
+        " referring to this vector");
+#endif
+    _LIBCPP_ASSERT(__position != end(),
+        "vector::erase(iterator) called with a non-dereferenceable iterator");
+    difference_type __ps = __position - cbegin();
+    pointer __p = this->__begin_ + __ps;
+    this->__destruct_at_end(_VSTD::move(__p + 1, this->__end_, __p));
+    this->__invalidate_iterators_past(__p-1);
+    iterator __r = __make_iter(__p);
+    return __r;
+}
+
+template <class _Tp, class _Allocator>
+typename vector<_Tp, _Allocator>::iterator
+vector<_Tp, _Allocator>::erase(const_iterator __first, const_iterator __last)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__first) == this,
+        "vector::erase(iterator,  iterator) called with an iterator not"
+        " referring to this vector");
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__last) == this,
+        "vector::erase(iterator,  iterator) called with an iterator not"
+        " referring to this vector");
+#endif
+    _LIBCPP_ASSERT(__first <= __last, "vector::erase(first, last) called with invalid range");
+    pointer __p = this->__begin_ + (__first - begin());
+    if (__first != __last) {
+        this->__destruct_at_end(_VSTD::move(__p + (__last - __first), this->__end_, __p));
+        this->__invalidate_iterators_past(__p - 1);
+    }
+    iterator __r = __make_iter(__p);
+    return __r;
+}
+
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::__move_range(pointer __from_s, pointer __from_e, pointer __to)
+{
+    pointer __old_last = this->__end_;
+    difference_type __n = __old_last - __to;
+    {
+      pointer __i = __from_s + __n;
+      _ConstructTransaction __tx(*this, __from_e - __i);
+      for (pointer __pos = __tx.__pos_; __i < __from_e;
+           ++__i, (void) ++__pos, __tx.__pos_ = __pos) {
+        __alloc_traits::construct(this->__alloc(),
+                                  _VSTD::__to_address(__pos),
+                                  _VSTD::move(*__i));
+      }
+    }
+    _VSTD::move_backward(__from_s, __from_s + __n, __old_last);
+}
+
+template <class _Tp, class _Allocator>
+typename vector<_Tp, _Allocator>::iterator
+vector<_Tp, _Allocator>::insert(const_iterator __position, const_reference __x)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__position) == this,
+        "vector::insert(iterator, x) called with an iterator not"
+        " referring to this vector");
+#endif
+    pointer __p = this->__begin_ + (__position - begin());
+    if (this->__end_ < this->__end_cap())
+    {
+        if (__p == this->__end_)
+        {
+            __construct_one_at_end(__x);
+        }
+        else
+        {
+            __move_range(__p, this->__end_, __p + 1);
+            const_pointer __xr = pointer_traits<const_pointer>::pointer_to(__x);
+            if (__p <= __xr && __xr < this->__end_)
+                ++__xr;
+            *__p = *__xr;
+        }
+    }
+    else
+    {
+        allocator_type& __a = this->__alloc();
+        __split_buffer<value_type, allocator_type&> __v(__recommend(size() + 1), __p - this->__begin_, __a);
+        __v.push_back(__x);
+        __p = __swap_out_circular_buffer(__v, __p);
+    }
+    return __make_iter(__p);
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Allocator>
+typename vector<_Tp, _Allocator>::iterator
+vector<_Tp, _Allocator>::insert(const_iterator __position, value_type&& __x)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__position) == this,
+        "vector::insert(iterator, x) called with an iterator not"
+        " referring to this vector");
+#endif
+    pointer __p = this->__begin_ + (__position - begin());
+    if (this->__end_ < this->__end_cap())
+    {
+        if (__p == this->__end_)
+        {
+            __construct_one_at_end(_VSTD::move(__x));
+        }
+        else
+        {
+            __move_range(__p, this->__end_, __p + 1);
+            *__p = _VSTD::move(__x);
+        }
+    }
+    else
+    {
+        allocator_type& __a = this->__alloc();
+        __split_buffer<value_type, allocator_type&> __v(__recommend(size() + 1), __p - this->__begin_, __a);
+        __v.push_back(_VSTD::move(__x));
+        __p = __swap_out_circular_buffer(__v, __p);
+    }
+    return __make_iter(__p);
+}
+
+template <class _Tp, class _Allocator>
+template <class... _Args>
+typename vector<_Tp, _Allocator>::iterator
+vector<_Tp, _Allocator>::emplace(const_iterator __position, _Args&&... __args)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__position) == this,
+        "vector::emplace(iterator, x) called with an iterator not"
+        " referring to this vector");
+#endif
+    pointer __p = this->__begin_ + (__position - begin());
+    if (this->__end_ < this->__end_cap())
+    {
+        if (__p == this->__end_)
+        {
+            __construct_one_at_end(_VSTD::forward<_Args>(__args)...);
+        }
+        else
+        {
+            __temp_value<value_type, _Allocator> __tmp(this->__alloc(), _VSTD::forward<_Args>(__args)...);
+            __move_range(__p, this->__end_, __p + 1);
+            *__p = _VSTD::move(__tmp.get());
+        }
+    }
+    else
+    {
+        allocator_type& __a = this->__alloc();
+        __split_buffer<value_type, allocator_type&> __v(__recommend(size() + 1), __p - this->__begin_, __a);
+        __v.emplace_back(_VSTD::forward<_Args>(__args)...);
+        __p = __swap_out_circular_buffer(__v, __p);
+    }
+    return __make_iter(__p);
+}
+
+#endif // !_LIBCPP_CXX03_LANG
+
+template <class _Tp, class _Allocator>
+typename vector<_Tp, _Allocator>::iterator
+vector<_Tp, _Allocator>::insert(const_iterator __position, size_type __n, const_reference __x)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__position) == this,
+        "vector::insert(iterator, n, x) called with an iterator not"
+        " referring to this vector");
+#endif
+    pointer __p = this->__begin_ + (__position - begin());
+    if (__n > 0)
+    {
+        if (__n <= static_cast<size_type>(this->__end_cap() - this->__end_))
+        {
+            size_type __old_n = __n;
+            pointer __old_last = this->__end_;
+            if (__n > static_cast<size_type>(this->__end_ - __p))
+            {
+                size_type __cx = __n - (this->__end_ - __p);
+                __construct_at_end(__cx, __x);
+                __n -= __cx;
+            }
+            if (__n > 0)
+            {
+                __move_range(__p, __old_last, __p + __old_n);
+                const_pointer __xr = pointer_traits<const_pointer>::pointer_to(__x);
+                if (__p <= __xr && __xr < this->__end_)
+                    __xr += __old_n;
+                _VSTD::fill_n(__p, __n, *__xr);
+            }
+        }
+        else
+        {
+            allocator_type& __a = this->__alloc();
+            __split_buffer<value_type, allocator_type&> __v(__recommend(size() + __n), __p - this->__begin_, __a);
+            __v.__construct_at_end(__n, __x);
+            __p = __swap_out_circular_buffer(__v, __p);
+        }
+    }
+    return __make_iter(__p);
+}
+
+template <class _Tp, class _Allocator>
+template <class _InputIterator>
+typename enable_if
+<
+     __is_cpp17_input_iterator  <_InputIterator>::value &&
+    !__is_cpp17_forward_iterator<_InputIterator>::value &&
+    is_constructible<
+       _Tp,
+       typename iterator_traits<_InputIterator>::reference>::value,
+    typename vector<_Tp, _Allocator>::iterator
+>::type
+vector<_Tp, _Allocator>::insert(const_iterator __position, _InputIterator __first, _InputIterator __last)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__position) == this,
+        "vector::insert(iterator, range) called with an iterator not"
+        " referring to this vector");
+#endif
+    difference_type __off = __position - begin();
+    pointer __p = this->__begin_ + __off;
+    allocator_type& __a = this->__alloc();
+    pointer __old_last = this->__end_;
+    for (; this->__end_ != this->__end_cap() && __first != __last; ++__first)
+    {
+        __construct_one_at_end(*__first);
+    }
+    __split_buffer<value_type, allocator_type&> __v(__a);
+    if (__first != __last)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            __v.__construct_at_end(__first, __last);
+            difference_type __old_size = __old_last - this->__begin_;
+            difference_type __old_p = __p - this->__begin_;
+            reserve(__recommend(size() + __v.size()));
+            __p = this->__begin_ + __old_p;
+            __old_last = this->__begin_ + __old_size;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            erase(__make_iter(__old_last), end());
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+    __p = _VSTD::rotate(__p, __old_last, this->__end_);
+    insert(__make_iter(__p), _VSTD::make_move_iterator(__v.begin()),
+                             _VSTD::make_move_iterator(__v.end()));
+    return begin() + __off;
+}
+
+template <class _Tp, class _Allocator>
+template <class _ForwardIterator>
+typename enable_if
+<
+    __is_cpp17_forward_iterator<_ForwardIterator>::value &&
+    is_constructible<
+       _Tp,
+       typename iterator_traits<_ForwardIterator>::reference>::value,
+    typename vector<_Tp, _Allocator>::iterator
+>::type
+vector<_Tp, _Allocator>::insert(const_iterator __position, _ForwardIterator __first, _ForwardIterator __last)
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__position) == this,
+        "vector::insert(iterator, range) called with an iterator not"
+        " referring to this vector");
+#endif
+    pointer __p = this->__begin_ + (__position - begin());
+    difference_type __n = _VSTD::distance(__first, __last);
+    if (__n > 0)
+    {
+        if (__n <= this->__end_cap() - this->__end_)
+        {
+            size_type __old_n = __n;
+            pointer __old_last = this->__end_;
+            _ForwardIterator __m = __last;
+            difference_type __dx = this->__end_ - __p;
+            if (__n > __dx)
+            {
+                __m = __first;
+                difference_type __diff = this->__end_ - __p;
+                _VSTD::advance(__m, __diff);
+                __construct_at_end(__m, __last, __n - __diff);
+                __n = __dx;
+            }
+            if (__n > 0)
+            {
+                __move_range(__p, __old_last, __p + __old_n);
+                _VSTD::copy(__first, __m, __p);
+            }
+        }
+        else
+        {
+            allocator_type& __a = this->__alloc();
+            __split_buffer<value_type, allocator_type&> __v(__recommend(size() + __n), __p - this->__begin_, __a);
+            __v.__construct_at_end(__first, __last);
+            __p = __swap_out_circular_buffer(__v, __p);
+        }
+    }
+    return __make_iter(__p);
+}
+
+#if _YNDX_LIBCXX_ENABLE_VECTOR_POD_RESIZE_UNINITIALIZED
+
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::resize_uninitialized(size_type __sz)
+{
+    size_type __cs = size();
+    if (__cs < __sz)
+        this->__append_uninitialized(__sz - __cs);
+    else if (__cs > __sz) {
+        this->__end_ = this->__begin_ + __sz;
+        __annotate_shrink(__cs);
+    }
+}
+
+#endif
+
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::resize(size_type __sz)
+{
+    size_type __cs = size();
+    if (__cs < __sz)
+        this->__append(__sz - __cs);
+    else if (__cs > __sz)
+        this->__destruct_at_end(this->__begin_ + __sz);
+}
+
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::resize(size_type __sz, const_reference __x)
+{
+    size_type __cs = size();
+    if (__cs < __sz)
+        this->__append(__sz - __cs, __x);
+    else if (__cs > __sz)
+        this->__destruct_at_end(this->__begin_ + __sz);
+}
+
+template <class _Tp, class _Allocator>
+void
+vector<_Tp, _Allocator>::swap(vector& __x)
+#if _LIBCPP_STD_VER >= 14
+    _NOEXCEPT
+#else
+    _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                __is_nothrow_swappable<allocator_type>::value)
+#endif
+{
+    _LIBCPP_ASSERT(__alloc_traits::propagate_on_container_swap::value ||
+                   this->__alloc() == __x.__alloc(),
+                   "vector::swap: Either propagate_on_container_swap must be true"
+                   " or the allocators must compare equal");
+    _VSTD::swap(this->__begin_, __x.__begin_);
+    _VSTD::swap(this->__end_, __x.__end_);
+    _VSTD::swap(this->__end_cap(), __x.__end_cap());
+    _VSTD::__swap_allocator(this->__alloc(), __x.__alloc(),
+        integral_constant<bool,__alloc_traits::propagate_on_container_swap::value>());
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->swap(this, &__x);
+#endif
+}
+
+template <class _Tp, class _Allocator>
+bool
+vector<_Tp, _Allocator>::__invariants() const
+{
+    if (this->__begin_ == nullptr)
+    {
+        if (this->__end_ != nullptr || this->__end_cap() != nullptr)
+            return false;
+    }
+    else
+    {
+        if (this->__begin_ > this->__end_)
+            return false;
+        if (this->__begin_ == this->__end_cap())
+            return false;
+        if (this->__end_ > this->__end_cap())
+            return false;
+    }
+    return true;
+}
+
+#if _LIBCPP_DEBUG_LEVEL == 2
+
+template <class _Tp, class _Allocator>
+bool
+vector<_Tp, _Allocator>::__dereferenceable(const const_iterator* __i) const
+{
+    return this->__begin_ <= __i->base() && __i->base() < this->__end_;
+}
+
+template <class _Tp, class _Allocator>
+bool
+vector<_Tp, _Allocator>::__decrementable(const const_iterator* __i) const
+{
+    return this->__begin_ < __i->base() && __i->base() <= this->__end_;
+}
+
+template <class _Tp, class _Allocator>
+bool
+vector<_Tp, _Allocator>::__addable(const const_iterator* __i, ptrdiff_t __n) const
+{
+    const_pointer __p = __i->base() + __n;
+    return this->__begin_ <= __p && __p <= this->__end_;
+}
+
+template <class _Tp, class _Allocator>
+bool
+vector<_Tp, _Allocator>::__subscriptable(const const_iterator* __i, ptrdiff_t __n) const
+{
+    const_pointer __p = __i->base() + __n;
+    return this->__begin_ <= __p && __p < this->__end_;
+}
+
+#endif // _LIBCPP_DEBUG_LEVEL == 2
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+vector<_Tp, _Allocator>::__invalidate_all_iterators()
+{
+#if _LIBCPP_DEBUG_LEVEL == 2
+    __get_db()->__invalidate_all(this);
+#endif
+}
+
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+vector<_Tp, _Allocator>::__invalidate_iterators_past(pointer __new_last) {
+#if _LIBCPP_DEBUG_LEVEL == 2
+  __c_node* __c = __get_db()->__find_c_and_lock(this);
+  for (__i_node** __p = __c->end_; __p != __c->beg_; ) {
+    --__p;
+    const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);
+    if (__i->base() > __new_last) {
+      (*__p)->__c_ = nullptr;
+      if (--__c->end_ != __p)
+        _VSTD::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
+    }
+  }
+  __get_db()->unlock();
+#else
+  ((void)__new_last);
+#endif
+}
+
+#if _YNDX_LIBCXX_ENABLE_VECTOR_BOOL_COMPRESSION == 1
+// vector<bool>
+
+template <class _Allocator> class vector<bool, _Allocator>;
+
+template <class _Allocator> struct hash<vector<bool, _Allocator> >;
+
+template <class _Allocator>
+struct __has_storage_type<vector<bool, _Allocator> >
+{
+    static const bool value = true;
+};
+
+template <class _Allocator>
+class _LIBCPP_TEMPLATE_VIS vector<bool, _Allocator>
+    : private __vector_base_common<true>
+{
+public:
+    typedef vector                                   __self;
+    typedef bool                                     value_type;
+    typedef _Allocator                               allocator_type;
+    typedef allocator_traits<allocator_type>         __alloc_traits;
+    typedef typename __alloc_traits::size_type       size_type;
+    typedef typename __alloc_traits::difference_type difference_type;
+    typedef size_type __storage_type;
+    typedef __bit_iterator<vector, false>            pointer;
+    typedef __bit_iterator<vector, true>             const_pointer;
+    typedef pointer                                  iterator;
+    typedef const_pointer                            const_iterator;
+    typedef _VSTD::reverse_iterator<iterator>         reverse_iterator;
+    typedef _VSTD::reverse_iterator<const_iterator>   const_reverse_iterator;
+
+private:
+    typedef typename __rebind_alloc_helper<__alloc_traits, __storage_type>::type __storage_allocator;
+    typedef allocator_traits<__storage_allocator>    __storage_traits;
+    typedef typename __storage_traits::pointer       __storage_pointer;
+    typedef typename __storage_traits::const_pointer __const_storage_pointer;
+
+    __storage_pointer                                      __begin_;
+    size_type                                              __size_;
+    __compressed_pair<size_type, __storage_allocator> __cap_alloc_;
+public:
+    typedef __bit_reference<vector>                  reference;
+    typedef __bit_const_reference<vector>            const_reference;
+private:
+    _LIBCPP_INLINE_VISIBILITY
+    size_type& __cap() _NOEXCEPT
+        {return __cap_alloc_.first();}
+    _LIBCPP_INLINE_VISIBILITY
+    const size_type& __cap() const _NOEXCEPT
+        {return __cap_alloc_.first();}
+    _LIBCPP_INLINE_VISIBILITY
+    __storage_allocator& __alloc() _NOEXCEPT
+        {return __cap_alloc_.second();}
+    _LIBCPP_INLINE_VISIBILITY
+    const __storage_allocator& __alloc() const _NOEXCEPT
+        {return __cap_alloc_.second();}
+
+    static const unsigned __bits_per_word = static_cast<unsigned>(sizeof(__storage_type) * CHAR_BIT);
+
+    _LIBCPP_INLINE_VISIBILITY
+    static size_type __internal_cap_to_external(size_type __n) _NOEXCEPT
+        {return __n * __bits_per_word;}
+    _LIBCPP_INLINE_VISIBILITY
+    static size_type __external_cap_to_internal(size_type __n) _NOEXCEPT
+        {return (__n - 1) / __bits_per_word + 1;}
+
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    vector() _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value);
+
+    _LIBCPP_INLINE_VISIBILITY explicit vector(const allocator_type& __a)
+#if _LIBCPP_STD_VER <= 14
+        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value);
+#else
+        _NOEXCEPT;
+#endif
+    ~vector();
+    explicit vector(size_type __n);
+#if _LIBCPP_STD_VER > 11
+    explicit vector(size_type __n, const allocator_type& __a);
+#endif
+    vector(size_type __n, const value_type& __v);
+    vector(size_type __n, const value_type& __v, const allocator_type& __a);
+    template <class _InputIterator>
+        vector(_InputIterator __first, _InputIterator __last,
+               typename enable_if<__is_cpp17_input_iterator  <_InputIterator>::value &&
+                                 !__is_cpp17_forward_iterator<_InputIterator>::value>::type* = 0);
+    template <class _InputIterator>
+        vector(_InputIterator __first, _InputIterator __last, const allocator_type& __a,
+               typename enable_if<__is_cpp17_input_iterator  <_InputIterator>::value &&
+                                 !__is_cpp17_forward_iterator<_InputIterator>::value>::type* = 0);
+    template <class _ForwardIterator>
+        vector(_ForwardIterator __first, _ForwardIterator __last,
+               typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value>::type* = 0);
+    template <class _ForwardIterator>
+        vector(_ForwardIterator __first, _ForwardIterator __last, const allocator_type& __a,
+               typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value>::type* = 0);
+
+    vector(const vector& __v);
+    vector(const vector& __v, const allocator_type& __a);
+    vector& operator=(const vector& __v);
+
+#ifndef _LIBCPP_CXX03_LANG
+    vector(initializer_list<value_type> __il);
+    vector(initializer_list<value_type> __il, const allocator_type& __a);
+
+    _LIBCPP_INLINE_VISIBILITY
+    vector(vector&& __v)
+#if _LIBCPP_STD_VER > 14
+        _NOEXCEPT;
+#else
+        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value);
+#endif
+    vector(vector&& __v, const __identity_t<allocator_type>& __a);
+    _LIBCPP_INLINE_VISIBILITY
+    vector& operator=(vector&& __v)
+        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value));
+
+    _LIBCPP_INLINE_VISIBILITY
+    vector& operator=(initializer_list<value_type> __il)
+        {assign(__il.begin(), __il.end()); return *this;}
+
+#endif // !_LIBCPP_CXX03_LANG
+
+    template <class _InputIterator>
+        typename enable_if
+        <
+            __is_cpp17_input_iterator<_InputIterator>::value &&
+           !__is_cpp17_forward_iterator<_InputIterator>::value,
+           void
+        >::type
+        assign(_InputIterator __first, _InputIterator __last);
+    template <class _ForwardIterator>
+        typename enable_if
+        <
+            __is_cpp17_forward_iterator<_ForwardIterator>::value,
+           void
+        >::type
+        assign(_ForwardIterator __first, _ForwardIterator __last);
+
+    void assign(size_type __n, const value_type& __x);
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    void assign(initializer_list<value_type> __il)
+        {assign(__il.begin(), __il.end());}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY allocator_type get_allocator() const _NOEXCEPT
+        {return allocator_type(this->__alloc());}
+
+    size_type max_size() const _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    size_type capacity() const _NOEXCEPT
+        {return __internal_cap_to_external(__cap());}
+    _LIBCPP_INLINE_VISIBILITY
+    size_type size() const _NOEXCEPT
+        {return __size_;}
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
+    bool empty() const _NOEXCEPT
+        {return __size_ == 0;}
+    void reserve(size_type __n);
+    void shrink_to_fit() _NOEXCEPT;
+
+    _LIBCPP_INLINE_VISIBILITY
+    iterator begin() _NOEXCEPT
+        {return __make_iter(0);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin() const _NOEXCEPT
+        {return __make_iter(0);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator end() _NOEXCEPT
+        {return __make_iter(__size_);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()   const _NOEXCEPT
+        {return __make_iter(__size_);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    reverse_iterator rbegin() _NOEXCEPT
+        {return       reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rbegin() const _NOEXCEPT
+        {return const_reverse_iterator(end());}
+    _LIBCPP_INLINE_VISIBILITY
+    reverse_iterator rend() _NOEXCEPT
+        {return       reverse_iterator(begin());}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rend()   const _NOEXCEPT
+        {return const_reverse_iterator(begin());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator         cbegin()  const _NOEXCEPT
+        {return __make_iter(0);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator         cend()    const _NOEXCEPT
+        {return __make_iter(__size_);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crbegin() const _NOEXCEPT
+        {return rbegin();}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crend()   const _NOEXCEPT
+        {return rend();}
+
+    _LIBCPP_INLINE_VISIBILITY reference       operator[](size_type __n)       {return __make_ref(__n);}
+    _LIBCPP_INLINE_VISIBILITY const_reference operator[](size_type __n) const {return __make_ref(__n);}
+    reference       at(size_type __n);
+    const_reference at(size_type __n) const;
+
+    _LIBCPP_INLINE_VISIBILITY reference       front()       {return __make_ref(0);}
+    _LIBCPP_INLINE_VISIBILITY const_reference front() const {return __make_ref(0);}
+    _LIBCPP_INLINE_VISIBILITY reference       back()        {return __make_ref(__size_ - 1);}
+    _LIBCPP_INLINE_VISIBILITY const_reference back()  const {return __make_ref(__size_ - 1);}
+
+    void push_back(const value_type& __x);
+#if _LIBCPP_STD_VER > 11
+    template <class... _Args>
+#if _LIBCPP_STD_VER > 14
+    _LIBCPP_INLINE_VISIBILITY reference emplace_back(_Args&&... __args)
+#else
+    _LIBCPP_INLINE_VISIBILITY void      emplace_back(_Args&&... __args)
+#endif
+    {
+        push_back ( value_type ( _VSTD::forward<_Args>(__args)... ));
+#if _LIBCPP_STD_VER > 14
+        return this->back();
+#endif
+    }
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY void pop_back() {--__size_;}
+
+#if _LIBCPP_STD_VER > 11
+    template <class... _Args>
+   _LIBCPP_INLINE_VISIBILITY iterator emplace(const_iterator position, _Args&&... __args)
+        { return insert ( position, value_type ( _VSTD::forward<_Args>(__args)... )); }
+#endif
+
+    iterator insert(const_iterator __position, const value_type& __x);
+    iterator insert(const_iterator __position, size_type __n, const value_type& __x);
+    iterator insert(const_iterator __position, size_type __n, const_reference __x);
+    template <class _InputIterator>
+        typename enable_if
+        <
+             __is_cpp17_input_iterator  <_InputIterator>::value &&
+            !__is_cpp17_forward_iterator<_InputIterator>::value,
+            iterator
+        >::type
+        insert(const_iterator __position, _InputIterator __first, _InputIterator __last);
+    template <class _ForwardIterator>
+        typename enable_if
+        <
+            __is_cpp17_forward_iterator<_ForwardIterator>::value,
+            iterator
+        >::type
+        insert(const_iterator __position, _ForwardIterator __first, _ForwardIterator __last);
+
+#ifndef _LIBCPP_CXX03_LANG
+    _LIBCPP_INLINE_VISIBILITY
+    iterator insert(const_iterator __position, initializer_list<value_type> __il)
+        {return insert(__position, __il.begin(), __il.end());}
+#endif
+
+    _LIBCPP_INLINE_VISIBILITY iterator erase(const_iterator __position);
+    iterator erase(const_iterator __first, const_iterator __last);
+
+    _LIBCPP_INLINE_VISIBILITY
+    void clear() _NOEXCEPT {__size_ = 0;}
+
+    void swap(vector&)
+#if _LIBCPP_STD_VER >= 14
+        _NOEXCEPT;
+#else
+        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                    __is_nothrow_swappable<allocator_type>::value);
+#endif
+    static void swap(reference __x, reference __y) _NOEXCEPT { _VSTD::swap(__x, __y); }
+
+    void resize(size_type __sz, value_type __x = false);
+    void flip() _NOEXCEPT;
+
+    bool __invariants() const;
+
+private:
+    _LIBCPP_INLINE_VISIBILITY void __invalidate_all_iterators();
+    void __vallocate(size_type __n);
+    void __vdeallocate() _NOEXCEPT;
+    _LIBCPP_INLINE_VISIBILITY
+    static size_type __align_it(size_type __new_size) _NOEXCEPT
+        {return __new_size + (__bits_per_word-1) & ~((size_type)__bits_per_word-1);}
+    _LIBCPP_INLINE_VISIBILITY  size_type __recommend(size_type __new_size) const;
+    _LIBCPP_INLINE_VISIBILITY void __construct_at_end(size_type __n, bool __x);
+    template <class _ForwardIterator>
+        typename enable_if
+        <
+            __is_cpp17_forward_iterator<_ForwardIterator>::value,
+            void
+        >::type
+        __construct_at_end(_ForwardIterator __first, _ForwardIterator __last);
+    void __append(size_type __n, const_reference __x);
+    _LIBCPP_INLINE_VISIBILITY
+    reference __make_ref(size_type __pos) _NOEXCEPT
+        {return reference(__begin_ + __pos / __bits_per_word, __storage_type(1) << __pos % __bits_per_word);}
+    _LIBCPP_INLINE_VISIBILITY
+    const_reference __make_ref(size_type __pos) const _NOEXCEPT
+        {return const_reference(__begin_ + __pos / __bits_per_word, __storage_type(1) << __pos % __bits_per_word);}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __make_iter(size_type __pos) _NOEXCEPT
+        {return iterator(__begin_ + __pos / __bits_per_word, static_cast<unsigned>(__pos % __bits_per_word));}
+    _LIBCPP_INLINE_VISIBILITY
+    const_iterator __make_iter(size_type __pos) const _NOEXCEPT
+        {return const_iterator(__begin_ + __pos / __bits_per_word, static_cast<unsigned>(__pos % __bits_per_word));}
+    _LIBCPP_INLINE_VISIBILITY
+    iterator __const_iterator_cast(const_iterator __p) _NOEXCEPT
+        {return begin() + (__p - cbegin());}
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const vector& __v)
+        {__copy_assign_alloc(__v, integral_constant<bool,
+                      __storage_traits::propagate_on_container_copy_assignment::value>());}
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const vector& __c, true_type)
+        {
+            if (__alloc() != __c.__alloc())
+                __vdeallocate();
+            __alloc() = __c.__alloc();
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __copy_assign_alloc(const vector&, false_type)
+        {}
+
+    void __move_assign(vector& __c, false_type);
+    void __move_assign(vector& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value);
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(vector& __c)
+        _NOEXCEPT_(
+            !__storage_traits::propagate_on_container_move_assignment::value ||
+            is_nothrow_move_assignable<allocator_type>::value)
+        {__move_assign_alloc(__c, integral_constant<bool,
+                      __storage_traits::propagate_on_container_move_assignment::value>());}
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(vector& __c, true_type)
+        _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
+        {
+            __alloc() = _VSTD::move(__c.__alloc());
+        }
+
+    _LIBCPP_INLINE_VISIBILITY
+    void __move_assign_alloc(vector&, false_type)
+        _NOEXCEPT
+        {}
+
+    size_t __hash_code() const _NOEXCEPT;
+
+    friend class __bit_reference<vector>;
+    friend class __bit_const_reference<vector>;
+    friend class __bit_iterator<vector, false>;
+    friend class __bit_iterator<vector, true>;
+    friend struct __bit_array<vector>;
+    friend struct _LIBCPP_TEMPLATE_VIS hash<vector>;
+};
+
+template <class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+vector<bool, _Allocator>::__invalidate_all_iterators()
+{
+}
+
+//  Allocate space for __n objects
+//  throws length_error if __n > max_size()
+//  throws (probably bad_alloc) if memory run out
+//  Precondition:  __begin_ == __end_ == __cap() == 0
+//  Precondition:  __n > 0
+//  Postcondition:  capacity() == __n
+//  Postcondition:  size() == 0
+template <class _Allocator>
+void
+vector<bool, _Allocator>::__vallocate(size_type __n)
+{
+    if (__n > max_size())
+        this->__throw_length_error();
+    __n = __external_cap_to_internal(__n);
+    this->__begin_ = __storage_traits::allocate(this->__alloc(), __n);
+    this->__size_ = 0;
+    this->__cap() = __n;
+}
+
+template <class _Allocator>
+void
+vector<bool, _Allocator>::__vdeallocate() _NOEXCEPT
+{
+    if (this->__begin_ != nullptr)
+    {
+        __storage_traits::deallocate(this->__alloc(), this->__begin_, __cap());
+        __invalidate_all_iterators();
+        this->__begin_ = nullptr;
+        this->__size_ = this->__cap() = 0;
+    }
+}
+
+template <class _Allocator>
+typename vector<bool, _Allocator>::size_type
+vector<bool, _Allocator>::max_size() const _NOEXCEPT
+{
+    size_type __amax = __storage_traits::max_size(__alloc());
+    size_type __nmax = numeric_limits<size_type>::max() / 2;  // end() >= begin(), always
+    if (__nmax / __bits_per_word <= __amax)
+        return __nmax;
+    return __internal_cap_to_external(__amax);
+}
+
+//  Precondition:  __new_size > capacity()
+template <class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename vector<bool, _Allocator>::size_type
+vector<bool, _Allocator>::__recommend(size_type __new_size) const
+{
+    const size_type __ms = max_size();
+    if (__new_size > __ms)
+        this->__throw_length_error();
+    const size_type __cap = capacity();
+    if (__cap >= __ms / 2)
+        return __ms;
+    return _VSTD::max(2 * __cap, __align_it(__new_size));
+}
+
+//  Default constructs __n objects starting at __end_
+//  Precondition:  __n > 0
+//  Precondition:  size() + __n <= capacity()
+//  Postcondition:  size() == size() + __n
+template <class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+vector<bool, _Allocator>::__construct_at_end(size_type __n, bool __x)
+{
+    size_type __old_size = this->__size_;
+    this->__size_ += __n;
+    if (__old_size == 0 || ((__old_size - 1) / __bits_per_word) != ((this->__size_ - 1) / __bits_per_word))
+    {
+        if (this->__size_ <= __bits_per_word)
+            this->__begin_[0] = __storage_type(0);
+        else
+            this->__begin_[(this->__size_ - 1) / __bits_per_word] = __storage_type(0);
+    }
+    _VSTD::fill_n(__make_iter(__old_size), __n, __x);
+}
+
+template <class _Allocator>
+template <class _ForwardIterator>
+typename enable_if
+<
+    __is_cpp17_forward_iterator<_ForwardIterator>::value,
+    void
+>::type
+vector<bool, _Allocator>::__construct_at_end(_ForwardIterator __first, _ForwardIterator __last)
+{
+    size_type __old_size = this->__size_;
+    this->__size_ += _VSTD::distance(__first, __last);
+    if (__old_size == 0 || ((__old_size - 1) / __bits_per_word) != ((this->__size_ - 1) / __bits_per_word))
+    {
+        if (this->__size_ <= __bits_per_word)
+            this->__begin_[0] = __storage_type(0);
+        else
+            this->__begin_[(this->__size_ - 1) / __bits_per_word] = __storage_type(0);
+    }
+    _VSTD::copy(__first, __last, __make_iter(__old_size));
+}
+
+template <class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+vector<bool, _Allocator>::vector()
+    _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, __default_init_tag())
+{
+}
+
+template <class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+vector<bool, _Allocator>::vector(const allocator_type& __a)
+#if _LIBCPP_STD_VER <= 14
+        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
+#else
+        _NOEXCEPT
+#endif
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, static_cast<__storage_allocator>(__a))
+{
+}
+
+template <class _Allocator>
+vector<bool, _Allocator>::vector(size_type __n)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, __default_init_tag())
+{
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__n, false);
+    }
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _Allocator>
+vector<bool, _Allocator>::vector(size_type __n, const allocator_type& __a)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, static_cast<__storage_allocator>(__a))
+{
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__n, false);
+    }
+}
+#endif
+
+template <class _Allocator>
+vector<bool, _Allocator>::vector(size_type __n, const value_type& __x)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, __default_init_tag())
+{
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__n, __x);
+    }
+}
+
+template <class _Allocator>
+vector<bool, _Allocator>::vector(size_type __n, const value_type& __x, const allocator_type& __a)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, static_cast<__storage_allocator>(__a))
+{
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__n, __x);
+    }
+}
+
+template <class _Allocator>
+template <class _InputIterator>
+vector<bool, _Allocator>::vector(_InputIterator __first, _InputIterator __last,
+       typename enable_if<__is_cpp17_input_iterator  <_InputIterator>::value &&
+                         !__is_cpp17_forward_iterator<_InputIterator>::value>::type*)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, __default_init_tag())
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        for (; __first != __last; ++__first)
+            push_back(*__first);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        if (__begin_ != nullptr)
+            __storage_traits::deallocate(__alloc(), __begin_, __cap());
+        __invalidate_all_iterators();
+        throw;
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template <class _Allocator>
+template <class _InputIterator>
+vector<bool, _Allocator>::vector(_InputIterator __first, _InputIterator __last, const allocator_type& __a,
+       typename enable_if<__is_cpp17_input_iterator  <_InputIterator>::value &&
+                         !__is_cpp17_forward_iterator<_InputIterator>::value>::type*)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, static_cast<__storage_allocator>(__a))
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        for (; __first != __last; ++__first)
+            push_back(*__first);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        if (__begin_ != nullptr)
+            __storage_traits::deallocate(__alloc(), __begin_, __cap());
+        __invalidate_all_iterators();
+        throw;
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template <class _Allocator>
+template <class _ForwardIterator>
+vector<bool, _Allocator>::vector(_ForwardIterator __first, _ForwardIterator __last,
+                                typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value>::type*)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, __default_init_tag())
+{
+    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__first, __last);
+    }
+}
+
+template <class _Allocator>
+template <class _ForwardIterator>
+vector<bool, _Allocator>::vector(_ForwardIterator __first, _ForwardIterator __last, const allocator_type& __a,
+                                typename enable_if<__is_cpp17_forward_iterator<_ForwardIterator>::value>::type*)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, static_cast<__storage_allocator>(__a))
+{
+    size_type __n = static_cast<size_type>(_VSTD::distance(__first, __last));
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__first, __last);
+    }
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Allocator>
+vector<bool, _Allocator>::vector(initializer_list<value_type> __il)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, __default_init_tag())
+{
+    size_type __n = static_cast<size_type>(__il.size());
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__il.begin(), __il.end());
+    }
+}
+
+template <class _Allocator>
+vector<bool, _Allocator>::vector(initializer_list<value_type> __il, const allocator_type& __a)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, static_cast<__storage_allocator>(__a))
+{
+    size_type __n = static_cast<size_type>(__il.size());
+    if (__n > 0)
+    {
+        __vallocate(__n);
+        __construct_at_end(__il.begin(), __il.end());
+    }
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+template <class _Allocator>
+vector<bool, _Allocator>::~vector()
+{
+    if (__begin_ != nullptr)
+        __storage_traits::deallocate(__alloc(), __begin_, __cap());
+    __invalidate_all_iterators();
+}
+
+template <class _Allocator>
+vector<bool, _Allocator>::vector(const vector& __v)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, __storage_traits::select_on_container_copy_construction(__v.__alloc()))
+{
+    if (__v.size() > 0)
+    {
+        __vallocate(__v.size());
+        __construct_at_end(__v.begin(), __v.end());
+    }
+}
+
+template <class _Allocator>
+vector<bool, _Allocator>::vector(const vector& __v, const allocator_type& __a)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, __a)
+{
+    if (__v.size() > 0)
+    {
+        __vallocate(__v.size());
+        __construct_at_end(__v.begin(), __v.end());
+    }
+}
+
+template <class _Allocator>
+vector<bool, _Allocator>&
+vector<bool, _Allocator>::operator=(const vector& __v)
+{
+    if (this != _VSTD::addressof(__v))
+    {
+        __copy_assign_alloc(__v);
+        if (__v.__size_)
+        {
+            if (__v.__size_ > capacity())
+            {
+                __vdeallocate();
+                __vallocate(__v.__size_);
+            }
+            _VSTD::copy(__v.__begin_, __v.__begin_ + __external_cap_to_internal(__v.__size_), __begin_);
+        }
+        __size_ = __v.__size_;
+    }
+    return *this;
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template <class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY vector<bool, _Allocator>::vector(vector&& __v)
+#if _LIBCPP_STD_VER > 14
+    _NOEXCEPT
+#else
+    _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
+#endif
+    : __begin_(__v.__begin_),
+      __size_(__v.__size_),
+      __cap_alloc_(_VSTD::move(__v.__cap_alloc_)) {
+    __v.__begin_ = nullptr;
+    __v.__size_ = 0;
+    __v.__cap() = 0;
+}
+
+template <class _Allocator>
+vector<bool, _Allocator>::vector(vector&& __v, const __identity_t<allocator_type>& __a)
+    : __begin_(nullptr),
+      __size_(0),
+      __cap_alloc_(0, __a)
+{
+    if (__a == allocator_type(__v.__alloc()))
+    {
+        this->__begin_ = __v.__begin_;
+        this->__size_ = __v.__size_;
+        this->__cap() = __v.__cap();
+        __v.__begin_ = nullptr;
+        __v.__cap() = __v.__size_ = 0;
+    }
+    else if (__v.size() > 0)
+    {
+        __vallocate(__v.size());
+        __construct_at_end(__v.begin(), __v.end());
+    }
+}
+
+template <class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+vector<bool, _Allocator>&
+vector<bool, _Allocator>::operator=(vector&& __v)
+    _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
+{
+    __move_assign(__v, integral_constant<bool,
+          __storage_traits::propagate_on_container_move_assignment::value>());
+    return *this;
+}
+
+template <class _Allocator>
+void
+vector<bool, _Allocator>::__move_assign(vector& __c, false_type)
+{
+    if (__alloc() != __c.__alloc())
+        assign(__c.begin(), __c.end());
+    else
+        __move_assign(__c, true_type());
+}
+
+template <class _Allocator>
+void
+vector<bool, _Allocator>::__move_assign(vector& __c, true_type)
+    _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value)
+{
+    __vdeallocate();
+    __move_assign_alloc(__c);
+    this->__begin_ = __c.__begin_;
+    this->__size_ = __c.__size_;
+    this->__cap() = __c.__cap();
+    __c.__begin_ = nullptr;
+    __c.__cap() = __c.__size_ = 0;
+}
+
+#endif // !_LIBCPP_CXX03_LANG
+
+template <class _Allocator>
+void
+vector<bool, _Allocator>::assign(size_type __n, const value_type& __x)
+{
+    __size_ = 0;
+    if (__n > 0)
+    {
+        size_type __c = capacity();
+        if (__n <= __c)
+            __size_ = __n;
+        else
+        {
+            vector __v(__alloc());
+            __v.reserve(__recommend(__n));
+            __v.__size_ = __n;
+            swap(__v);
+        }
+        _VSTD::fill_n(begin(), __n, __x);
+    }
+  __invalidate_all_iterators();
+}
+
+template <class _Allocator>
+template <class _InputIterator>
+typename enable_if
+<
+    __is_cpp17_input_iterator<_InputIterator>::value &&
+   !__is_cpp17_forward_iterator<_InputIterator>::value,
+   void
+>::type
+vector<bool, _Allocator>::assign(_InputIterator __first, _InputIterator __last)
+{
+    clear();
+    for (; __first != __last; ++__first)
+        push_back(*__first);
+}
+
+template <class _Allocator>
+template <class _ForwardIterator>
+typename enable_if
+<
+    __is_cpp17_forward_iterator<_ForwardIterator>::value,
+   void
+>::type
+vector<bool, _Allocator>::assign(_ForwardIterator __first, _ForwardIterator __last)
+{
+    clear();
+    difference_type __ns = _VSTD::distance(__first, __last);
+    _LIBCPP_ASSERT(__ns >= 0, "invalid range specified");
+    const size_t __n = static_cast<size_type>(__ns);
+    if (__n)
+    {
+        if (__n > capacity())
+        {
+            __vdeallocate();
+            __vallocate(__n);
+        }
+        __construct_at_end(__first, __last);
+    }
+}
+
+template <class _Allocator>
+void
+vector<bool, _Allocator>::reserve(size_type __n)
+{
+    if (__n > capacity())
+    {
+        vector __v(this->__alloc());
+        __v.__vallocate(__n);
+        __v.__construct_at_end(this->begin(), this->end());
+        swap(__v);
+        __invalidate_all_iterators();
+    }
+}
+
+template <class _Allocator>
+void
+vector<bool, _Allocator>::shrink_to_fit() _NOEXCEPT
+{
+    if (__external_cap_to_internal(size()) > __cap())
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            vector(*this, allocator_type(__alloc())).swap(*this);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+}
+
+template <class _Allocator>
+typename vector<bool, _Allocator>::reference
+vector<bool, _Allocator>::at(size_type __n)
+{
+    if (__n >= size())
+        this->__throw_out_of_range();
+    return (*this)[__n];
+}
+
+template <class _Allocator>
+typename vector<bool, _Allocator>::const_reference
+vector<bool, _Allocator>::at(size_type __n) const
+{
+    if (__n >= size())
+        this->__throw_out_of_range();
+    return (*this)[__n];
+}
+
+template <class _Allocator>
+void
+vector<bool, _Allocator>::push_back(const value_type& __x)
+{
+    if (this->__size_ == this->capacity())
+        reserve(__recommend(this->__size_ + 1));
+    ++this->__size_;
+    back() = __x;
+}
+
+template <class _Allocator>
+typename vector<bool, _Allocator>::iterator
+vector<bool, _Allocator>::insert(const_iterator __position, const value_type& __x)
+{
+    iterator __r;
+    if (size() < capacity())
+    {
+        const_iterator __old_end = end();
+        ++__size_;
+        _VSTD::copy_backward(__position, __old_end, end());
+        __r = __const_iterator_cast(__position);
+    }
+    else
+    {
+        vector __v(__alloc());
+        __v.reserve(__recommend(__size_ + 1));
+        __v.__size_ = __size_ + 1;
+        __r = _VSTD::copy(cbegin(), __position, __v.begin());
+        _VSTD::copy_backward(__position, cend(), __v.end());
+        swap(__v);
+    }
+    *__r = __x;
+    return __r;
+}
+
+template <class _Allocator>
+typename vector<bool, _Allocator>::iterator
+vector<bool, _Allocator>::insert(const_iterator __position, size_type __n, const value_type& __x)
+{
+    iterator __r;
+    size_type __c = capacity();
+    if (__n <= __c && size() <= __c - __n)
+    {
+        const_iterator __old_end = end();
+        __size_ += __n;
+        _VSTD::copy_backward(__position, __old_end, end());
+        __r = __const_iterator_cast(__position);
+    }
+    else
+    {
+        vector __v(__alloc());
+        __v.reserve(__recommend(__size_ + __n));
+        __v.__size_ = __size_ + __n;
+        __r = _VSTD::copy(cbegin(), __position, __v.begin());
+        _VSTD::copy_backward(__position, cend(), __v.end());
+        swap(__v);
+    }
+    _VSTD::fill_n(__r, __n, __x);
+    return __r;
+}
+
+template <class _Allocator>
+template <class _InputIterator>
+typename enable_if
+<
+     __is_cpp17_input_iterator  <_InputIterator>::value &&
+    !__is_cpp17_forward_iterator<_InputIterator>::value,
+    typename vector<bool, _Allocator>::iterator
+>::type
+vector<bool, _Allocator>::insert(const_iterator __position, _InputIterator __first, _InputIterator __last)
+{
+    difference_type __off = __position - begin();
+    iterator __p = __const_iterator_cast(__position);
+    iterator __old_end = end();
+    for (; size() != capacity() && __first != __last; ++__first)
+    {
+        ++this->__size_;
+        back() = *__first;
+    }
+    vector __v(__alloc());
+    if (__first != __last)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            __v.assign(__first, __last);
+            difference_type __old_size = static_cast<difference_type>(__old_end - begin());
+            difference_type __old_p = __p - begin();
+            reserve(__recommend(size() + __v.size()));
+            __p = begin() + __old_p;
+            __old_end = begin() + __old_size;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            erase(__old_end, end());
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+    __p = _VSTD::rotate(__p, __old_end, end());
+    insert(__p, __v.begin(), __v.end());
+    return begin() + __off;
+}
+
+template <class _Allocator>
+template <class _ForwardIterator>
+typename enable_if
+<
+    __is_cpp17_forward_iterator<_ForwardIterator>::value,
+    typename vector<bool, _Allocator>::iterator
+>::type
+vector<bool, _Allocator>::insert(const_iterator __position, _ForwardIterator __first, _ForwardIterator __last)
+{
+    const difference_type __n_signed = _VSTD::distance(__first, __last);
+    _LIBCPP_ASSERT(__n_signed >= 0, "invalid range specified");
+    const size_type __n = static_cast<size_type>(__n_signed);
+    iterator __r;
+    size_type __c = capacity();
+    if (__n <= __c && size() <= __c - __n)
+    {
+        const_iterator __old_end = end();
+        __size_ += __n;
+        _VSTD::copy_backward(__position, __old_end, end());
+        __r = __const_iterator_cast(__position);
+    }
+    else
+    {
+        vector __v(__alloc());
+        __v.reserve(__recommend(__size_ + __n));
+        __v.__size_ = __size_ + __n;
+        __r = _VSTD::copy(cbegin(), __position, __v.begin());
+        _VSTD::copy_backward(__position, cend(), __v.end());
+        swap(__v);
+    }
+    _VSTD::copy(__first, __last, __r);
+    return __r;
+}
+
+template <class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+typename vector<bool, _Allocator>::iterator
+vector<bool, _Allocator>::erase(const_iterator __position)
+{
+    iterator __r = __const_iterator_cast(__position);
+    _VSTD::copy(__position + 1, this->cend(), __r);
+    --__size_;
+    return __r;
+}
+
+template <class _Allocator>
+typename vector<bool, _Allocator>::iterator
+vector<bool, _Allocator>::erase(const_iterator __first, const_iterator __last)
+{
+    iterator __r = __const_iterator_cast(__first);
+    difference_type __d = __last - __first;
+    _VSTD::copy(__last, this->cend(), __r);
+    __size_ -= __d;
+    return __r;
+}
+
+template <class _Allocator>
+void
+vector<bool, _Allocator>::swap(vector& __x)
+#if _LIBCPP_STD_VER >= 14
+    _NOEXCEPT
+#else
+    _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
+                __is_nothrow_swappable<allocator_type>::value)
+#endif
+{
+    _VSTD::swap(this->__begin_, __x.__begin_);
+    _VSTD::swap(this->__size_, __x.__size_);
+    _VSTD::swap(this->__cap(), __x.__cap());
+    _VSTD::__swap_allocator(this->__alloc(), __x.__alloc(),
+        integral_constant<bool, __alloc_traits::propagate_on_container_swap::value>());
+}
+
+template <class _Allocator>
+void
+vector<bool, _Allocator>::resize(size_type __sz, value_type __x)
+{
+    size_type __cs = size();
+    if (__cs < __sz)
+    {
+        iterator __r;
+        size_type __c = capacity();
+        size_type __n = __sz - __cs;
+        if (__n <= __c && __cs <= __c - __n)
+        {
+            __r = end();
+            __size_ += __n;
+        }
+        else
+        {
+            vector __v(__alloc());
+            __v.reserve(__recommend(__size_ + __n));
+            __v.__size_ = __size_ + __n;
+            __r = _VSTD::copy(cbegin(), cend(), __v.begin());
+            swap(__v);
+        }
+        _VSTD::fill_n(__r, __n, __x);
+    }
+    else
+        __size_ = __sz;
+}
+
+template <class _Allocator>
+void
+vector<bool, _Allocator>::flip() _NOEXCEPT
+{
+    // do middle whole words
+    size_type __n = __size_;
+    __storage_pointer __p = __begin_;
+    for (; __n >= __bits_per_word; ++__p, __n -= __bits_per_word)
+        *__p = ~*__p;
+    // do last partial word
+    if (__n > 0)
+    {
+        __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+        __storage_type __b = *__p & __m;
+        *__p &= ~__m;
+        *__p |= ~__b & __m;
+    }
+}
+
+template <class _Allocator>
+bool
+vector<bool, _Allocator>::__invariants() const
+{
+    if (this->__begin_ == nullptr)
+    {
+        if (this->__size_ != 0 || this->__cap() != 0)
+            return false;
+    }
+    else
+    {
+        if (this->__cap() == 0)
+            return false;
+        if (this->__size_ > this->capacity())
+            return false;
+    }
+    return true;
+}
+
+template <class _Allocator>
+size_t
+vector<bool, _Allocator>::__hash_code() const _NOEXCEPT
+{
+    size_t __h = 0;
+    // do middle whole words
+    size_type __n = __size_;
+    __storage_pointer __p = __begin_;
+    for (; __n >= __bits_per_word; ++__p, __n -= __bits_per_word)
+        __h ^= *__p;
+    // do last partial word
+    if (__n > 0)
+    {
+        const __storage_type __m = ~__storage_type(0) >> (__bits_per_word - __n);
+        __h ^= *__p & __m;
+    }
+    return __h;
+}
+
+template <class _Allocator>
+struct _LIBCPP_TEMPLATE_VIS hash<vector<bool, _Allocator> >
+    : public unary_function<vector<bool, _Allocator>, size_t>
+{
+    _LIBCPP_INLINE_VISIBILITY
+    size_t operator()(const vector<bool, _Allocator>& __vec) const _NOEXCEPT
+        {return __vec.__hash_code();}
+};
+#endif // _YNDX_LIBCXX_DISABLE_VECTOR_BOOL_COMPRESSION
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator==(const vector<_Tp, _Allocator>& __x, const vector<_Tp, _Allocator>& __y)
+{
+    const typename vector<_Tp, _Allocator>::size_type __sz = __x.size();
+    return __sz == __y.size() && _VSTD::equal(__x.begin(), __x.end(), __y.begin());
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator!=(const vector<_Tp, _Allocator>& __x, const vector<_Tp, _Allocator>& __y)
+{
+    return !(__x == __y);
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator< (const vector<_Tp, _Allocator>& __x, const vector<_Tp, _Allocator>& __y)
+{
+    return _VSTD::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator> (const vector<_Tp, _Allocator>& __x, const vector<_Tp, _Allocator>& __y)
+{
+    return __y < __x;
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator>=(const vector<_Tp, _Allocator>& __x, const vector<_Tp, _Allocator>& __y)
+{
+    return !(__x < __y);
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+bool
+operator<=(const vector<_Tp, _Allocator>& __x, const vector<_Tp, _Allocator>& __y)
+{
+    return !(__y < __x);
+}
+
+template <class _Tp, class _Allocator>
+inline _LIBCPP_INLINE_VISIBILITY
+void
+swap(vector<_Tp, _Allocator>& __x, vector<_Tp, _Allocator>& __y)
+    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
+{
+    __x.swap(__y);
+}
+
+#if _LIBCPP_STD_VER > 17
+template <class _Tp, class _Allocator, class _Up>
+inline _LIBCPP_INLINE_VISIBILITY typename vector<_Tp, _Allocator>::size_type
+erase(vector<_Tp, _Allocator>& __c, const _Up& __v) {
+  auto __old_size = __c.size();
+  __c.erase(_VSTD::remove(__c.begin(), __c.end(), __v), __c.end());
+  return __old_size - __c.size();
+}
+
+template <class _Tp, class _Allocator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY typename vector<_Tp, _Allocator>::size_type
+erase_if(vector<_Tp, _Allocator>& __c, _Predicate __pred) {
+  auto __old_size = __c.size();
+  __c.erase(_VSTD::remove_if(__c.begin(), __c.end(), __pred), __c.end());
+  return __old_size - __c.size();
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_VECTOR
diff --git a/contrib/libs/cxxsupp/libcxx/include/version b/contrib/libs/cxxsupp/libcxx/include/version
new file mode 100644
index 00000000000..0e15cfad809
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/version
@@ -0,0 +1,378 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_VERSIONH
+#define _LIBCPP_VERSIONH
+
+/*
+  version synopsis
+
+Macro name                                              Value   Headers
+__cpp_lib_addressof_constexpr                           201603L <memory>
+__cpp_lib_allocator_traits_is_always_equal              201411L <deque> <forward_list> <list>
+                                                                <map> <memory> <scoped_allocator>
+                                                                <set> <string> <unordered_map>
+                                                                <unordered_set> <vector>
+__cpp_lib_any                                           201606L <any>
+__cpp_lib_apply                                         201603L <tuple>
+__cpp_lib_array_constexpr                               201811L <array> <iterator>
+                                                        201603L // C++17
+__cpp_lib_as_const                                      201510L <utility>
+__cpp_lib_assume_aligned                                201811L <memory>
+__cpp_lib_atomic_flag_test                              201907L <atomic>
+__cpp_lib_atomic_float                                  201711L <atomic>
+__cpp_lib_atomic_is_always_lock_free                    201603L <atomic>
+__cpp_lib_atomic_lock_free_type_aliases                 201907L <atomic>
+__cpp_lib_atomic_ref                                    201806L <atomic>
+__cpp_lib_atomic_shared_ptr                             201711L <atomic>
+__cpp_lib_atomic_value_initialization                   201911L <atomic> <memory>
+__cpp_lib_atomic_wait                                   201907L <atomic>
+__cpp_lib_barrier                                       201907L <barrier>
+__cpp_lib_bind_front                                    201907L <functional>
+__cpp_lib_bit_cast                                      201806L <bit>
+__cpp_lib_bitops                                        201907L <bit>
+__cpp_lib_bool_constant                                 201505L <type_traits>
+__cpp_lib_bounded_array_traits                          201902L <type_traits>
+__cpp_lib_boyer_moore_searcher                          201603L <functional>
+__cpp_lib_byte                                          201603L <cstddef>
+__cpp_lib_char8_t                                       201907L <atomic> <filesystem> <istream>
+                                                                <limits> <locale> <ostream>
+                                                                <string> <string_view>
+__cpp_lib_chrono                                        201611L <chrono>
+__cpp_lib_chrono_udls                                   201304L <chrono>
+__cpp_lib_clamp                                         201603L <algorithm>
+__cpp_lib_complex_udls                                  201309L <complex>
+__cpp_lib_concepts                                      202002L <concepts>
+__cpp_lib_constexpr_algorithms                          201806L <algorithm>
+__cpp_lib_constexpr_complex                             201711L <complex>
+__cpp_lib_constexpr_dynamic_alloc                       201907L <memory>
+__cpp_lib_constexpr_functional                          201907L <functional>
+__cpp_lib_constexpr_iterator                            201811L <iterator>
+__cpp_lib_constexpr_memory                              201811L <memory>
+__cpp_lib_constexpr_numeric                             201911L <numeric>
+__cpp_lib_constexpr_string                              201811L <string>
+__cpp_lib_constexpr_string_view                         201811L <string_view>
+__cpp_lib_constexpr_tuple                               201811L <tuple>
+__cpp_lib_constexpr_utility                             201811L <utility>
+__cpp_lib_constexpr_vector                              201907L <vector>
+__cpp_lib_coroutine                                     201902L <coroutine>
+__cpp_lib_destroying_delete                             201806L <new>
+__cpp_lib_enable_shared_from_this                       201603L <memory>
+__cpp_lib_endian                                        201907L <bit>
+__cpp_lib_erase_if                                      202002L <deque> <forward_list> <list>
+                                                                <map> <set> <string>
+                                                                <unordered_map> <unordered_set> <vector>
+__cpp_lib_exchange_function                             201304L <utility>
+__cpp_lib_execution                                     201902L <execution>
+                                                        201603L // C++17
+__cpp_lib_filesystem                                    201703L <filesystem>
+__cpp_lib_format                                        201907L <format>
+__cpp_lib_gcd_lcm                                       201606L <numeric>
+__cpp_lib_generic_associative_lookup                    201304L <map> <set>
+__cpp_lib_generic_unordered_lookup                      201811L <unordered_map> <unordered_set>
+__cpp_lib_hardware_interference_size                    201703L <new>
+__cpp_lib_has_unique_object_representations             201606L <type_traits>
+__cpp_lib_hypot                                         201603L <cmath>
+__cpp_lib_incomplete_container_elements                 201505L <forward_list> <list> <vector>
+__cpp_lib_int_pow2                                      202002L <bit>
+__cpp_lib_integer_comparison_functions                  202002L <utility>
+__cpp_lib_integer_sequence                              201304L <utility>
+__cpp_lib_integral_constant_callable                    201304L <type_traits>
+__cpp_lib_interpolate                                   201902L <cmath> <numeric>
+__cpp_lib_invoke                                        201411L <functional>
+__cpp_lib_is_aggregate                                  201703L <type_traits>
+__cpp_lib_is_constant_evaluated                         201811L <type_traits>
+__cpp_lib_is_final                                      201402L <type_traits>
+__cpp_lib_is_invocable                                  201703L <type_traits>
+__cpp_lib_is_layout_compatible                          201907L <type_traits>
+__cpp_lib_is_nothrow_convertible                        201806L <type_traits>
+__cpp_lib_is_null_pointer                               201309L <type_traits>
+__cpp_lib_is_pointer_interconvertible                   201907L <type_traits>
+__cpp_lib_is_scoped_enum                                202011L <type_traits>
+__cpp_lib_is_swappable                                  201603L <type_traits>
+__cpp_lib_jthread                                       201911L <stop_token> <thread>
+__cpp_lib_latch                                         201907L <latch>
+__cpp_lib_launder                                       201606L <new>
+__cpp_lib_list_remove_return_type                       201806L <forward_list> <list>
+__cpp_lib_logical_traits                                201510L <type_traits>
+__cpp_lib_make_from_tuple                               201606L <tuple>
+__cpp_lib_make_reverse_iterator                         201402L <iterator>
+__cpp_lib_make_unique                                   201304L <memory>
+__cpp_lib_map_try_emplace                               201411L <map>
+__cpp_lib_math_constants                                201907L <numbers>
+__cpp_lib_math_special_functions                        201603L <cmath>
+__cpp_lib_memory_resource                               201603L <memory_resource>
+__cpp_lib_node_extract                                  201606L <map> <set> <unordered_map>
+                                                                <unordered_set>
+__cpp_lib_nonmember_container_access                    201411L <array> <deque> <forward_list>
+                                                                <iterator> <list> <map>
+                                                                <regex> <set> <string>
+                                                                <unordered_map> <unordered_set> <vector>
+__cpp_lib_not_fn                                        201603L <functional>
+__cpp_lib_null_iterators                                201304L <iterator>
+__cpp_lib_optional                                      201606L <optional>
+__cpp_lib_parallel_algorithm                            201603L <algorithm> <numeric>
+__cpp_lib_polymorphic_allocator                         201902L <memory>
+__cpp_lib_quoted_string_io                              201304L <iomanip>
+__cpp_lib_ranges                                        201811L <algorithm> <functional> <iterator>
+                                                                <memory> <ranges>
+__cpp_lib_raw_memory_algorithms                         201606L <memory>
+__cpp_lib_remove_cvref                                  201711L <type_traits>
+__cpp_lib_result_of_sfinae                              201210L <functional> <type_traits>
+__cpp_lib_robust_nonmodifying_seq_ops                   201304L <algorithm>
+__cpp_lib_sample                                        201603L <algorithm>
+__cpp_lib_scoped_lock                                   201703L <mutex>
+__cpp_lib_semaphore                                     201907L <semaphore>
+__cpp_lib_shared_mutex                                  201505L <shared_mutex>
+__cpp_lib_shared_ptr_arrays                             201611L <memory>
+__cpp_lib_shared_ptr_weak_type                          201606L <memory>
+__cpp_lib_shared_timed_mutex                            201402L <shared_mutex>
+__cpp_lib_shift                                         201806L <algorithm>
+__cpp_lib_smart_ptr_for_overwrite                       202002L <memory>
+__cpp_lib_source_location                               201907L <source_location>
+__cpp_lib_span                                          202002L <span>
+__cpp_lib_ssize                                         201902L <iterator>
+__cpp_lib_stacktrace                                    202011L <stacktrace>
+__cpp_lib_starts_ends_with                              201711L <string> <string_view>
+__cpp_lib_stdatomic_h                                   202011L <stdatomic.h>
+__cpp_lib_string_contains                               202011L <string> <string_view>
+__cpp_lib_string_udls                                   201304L <string>
+__cpp_lib_string_view                                   201803L <string> <string_view>
+                                                        201606L // C++17
+__cpp_lib_syncbuf                                       201803L <syncstream>
+__cpp_lib_three_way_comparison                          201907L <compare>
+__cpp_lib_to_address                                    201711L <memory>
+__cpp_lib_to_array                                      201907L <array>
+__cpp_lib_to_chars                                      201611L <utility>
+__cpp_lib_to_underlying                                 202102L <utility>
+__cpp_lib_transformation_trait_aliases                  201304L <type_traits>
+__cpp_lib_transparent_operators                         201510L <functional> <memory>
+                                                        201210L // C++14
+__cpp_lib_tuple_element_t                               201402L <tuple>
+__cpp_lib_tuples_by_type                                201304L <tuple> <utility>
+__cpp_lib_type_trait_variable_templates                 201510L <type_traits>
+__cpp_lib_uncaught_exceptions                           201411L <exception>
+__cpp_lib_unordered_map_try_emplace                     201411L <unordered_map>
+__cpp_lib_unwrap_ref                                    201811L <functional>
+__cpp_lib_variant                                       202102L <variant>
+__cpp_lib_void_t                                        201411L <type_traits>
+
+*/
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+// clang-format off
+
+#if _LIBCPP_STD_VER > 11
+# define __cpp_lib_chrono_udls                          201304L
+# define __cpp_lib_complex_udls                         201309L
+# define __cpp_lib_exchange_function                    201304L
+# define __cpp_lib_generic_associative_lookup           201304L
+# define __cpp_lib_integer_sequence                     201304L
+# define __cpp_lib_integral_constant_callable           201304L
+# define __cpp_lib_is_final                             201402L
+# define __cpp_lib_is_null_pointer                      201309L
+# define __cpp_lib_make_reverse_iterator                201402L
+# define __cpp_lib_make_unique                          201304L
+# define __cpp_lib_null_iterators                       201304L
+# define __cpp_lib_quoted_string_io                     201304L
+# define __cpp_lib_result_of_sfinae                     201210L
+# define __cpp_lib_robust_nonmodifying_seq_ops          201304L
+# if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_shared_timed_mutex)
+#   define __cpp_lib_shared_timed_mutex                 201402L
+# endif
+# define __cpp_lib_string_udls                          201304L
+# define __cpp_lib_transformation_trait_aliases         201304L
+# define __cpp_lib_transparent_operators                201210L
+# define __cpp_lib_tuple_element_t                      201402L
+# define __cpp_lib_tuples_by_type                       201304L
+#endif
+
+#if _LIBCPP_STD_VER > 14
+# define __cpp_lib_addressof_constexpr                  201603L
+# define __cpp_lib_allocator_traits_is_always_equal     201411L
+# define __cpp_lib_any                                  201606L
+# define __cpp_lib_apply                                201603L
+# if defined(_MSC_VER) && _MSC_VER >= 1926
+#   define __cpp_lib_array_constexpr                    201803L
+# else
+#   define __cpp_lib_array_constexpr                    201603L
+# endif
+# define __cpp_lib_as_const                             201510L
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+#   define __cpp_lib_atomic_is_always_lock_free         201603L
+# endif
+# define __cpp_lib_bool_constant                        201505L
+// # define __cpp_lib_boyer_moore_searcher                 201603L
+# define __cpp_lib_byte                                 201603L
+# define __cpp_lib_chrono                               201611L
+# define __cpp_lib_clamp                                201603L
+# define __cpp_lib_enable_shared_from_this              201603L
+// # define __cpp_lib_execution                            201603L
+# if !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_filesystem)
+# define __cpp_lib_filesystem                           201703L
+# endif
+# define __cpp_lib_gcd_lcm                              201606L
+// # define __cpp_lib_hardware_interference_size           201703L
+# define __cpp_lib_has_unique_object_representations    201606L
+# define __cpp_lib_hypot                                201603L
+# define __cpp_lib_incomplete_container_elements        201505L
+# define __cpp_lib_invoke                               201411L
+# define __cpp_lib_is_aggregate                         201703L
+# define __cpp_lib_is_invocable                         201703L
+# define __cpp_lib_is_swappable                         201603L
+# define __cpp_lib_launder                              201606L
+# define __cpp_lib_logical_traits                       201510L
+# define __cpp_lib_make_from_tuple                      201606L
+# define __cpp_lib_map_try_emplace                      201411L
+// # define __cpp_lib_math_special_functions               201603L
+// # define __cpp_lib_memory_resource                      201603L
+# define __cpp_lib_node_extract                         201606L
+# define __cpp_lib_nonmember_container_access           201411L
+# define __cpp_lib_not_fn                               201603L
+# define __cpp_lib_optional                             201606L
+// # define __cpp_lib_parallel_algorithm                   201603L
+# define __cpp_lib_raw_memory_algorithms                201606L
+# define __cpp_lib_sample                               201603L
+# define __cpp_lib_scoped_lock                          201703L
+# if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_shared_mutex)
+#   define __cpp_lib_shared_mutex                       201505L
+# endif
+# define __cpp_lib_shared_ptr_arrays                    201611L
+# define __cpp_lib_shared_ptr_weak_type                 201606L
+# if defined(_MSC_VER) && _MSC_VER >= 1926
+#   define __cpp_lib_string_view                        201803L
+# else
+#   define __cpp_lib_string_view                        201606L
+# endif
+// # define __cpp_lib_to_chars                             201611L
+# undef  __cpp_lib_transparent_operators
+# define __cpp_lib_transparent_operators                201510L
+# define __cpp_lib_type_trait_variable_templates        201510L
+# define __cpp_lib_uncaught_exceptions                  201411L
+# define __cpp_lib_unordered_map_try_emplace            201411L
+# define __cpp_lib_variant                              202102L
+# define __cpp_lib_void_t                               201411L
+#endif
+
+#if _LIBCPP_STD_VER > 17
+# undef  __cpp_lib_array_constexpr
+# define __cpp_lib_array_constexpr                      201811L
+// # define __cpp_lib_assume_aligned                       201811L
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+#   define __cpp_lib_atomic_flag_test                   201907L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+// #   define __cpp_lib_atomic_float                       201711L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+#   define __cpp_lib_atomic_lock_free_type_aliases      201907L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+// #   define __cpp_lib_atomic_ref                         201806L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+// #   define __cpp_lib_atomic_shared_ptr                  201711L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+#   define __cpp_lib_atomic_value_initialization        201911L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_atomic_wait)
+#   define __cpp_lib_atomic_wait                        201907L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_barrier)
+#   define __cpp_lib_barrier                            201907L
+# endif
+# define __cpp_lib_bind_front                           201907L
+# define __cpp_lib_bit_cast                             201806L
+// # define __cpp_lib_bitops                               201907L
+# define __cpp_lib_bounded_array_traits                 201902L
+# if !defined(_LIBCPP_HAS_NO_CHAR8_T)
+#   define __cpp_lib_char8_t                            201907L
+# endif
+# define __cpp_lib_concepts                             202002L
+# define __cpp_lib_constexpr_algorithms                 201806L
+// # define __cpp_lib_constexpr_complex                    201711L
+# define __cpp_lib_constexpr_dynamic_alloc              201907L
+# define __cpp_lib_constexpr_functional                 201907L
+# define __cpp_lib_constexpr_iterator                   201811L
+# define __cpp_lib_constexpr_memory                     201811L
+# define __cpp_lib_constexpr_numeric                    201911L
+# define __cpp_lib_constexpr_string                     201811L
+# define __cpp_lib_constexpr_string_view                201811L
+# define __cpp_lib_constexpr_tuple                      201811L
+# define __cpp_lib_constexpr_utility                    201811L
+// # define __cpp_lib_constexpr_vector                     201907L
+// # define __cpp_lib_coroutine                            201902L
+# if _LIBCPP_STD_VER > 17 && defined(__cpp_impl_destroying_delete) && __cpp_impl_destroying_delete >= 201806L
+#   define __cpp_lib_destroying_delete                  201806L
+# endif
+# define __cpp_lib_endian                               201907L
+# define __cpp_lib_erase_if                             202002L
+# undef  __cpp_lib_execution
+// # define __cpp_lib_execution                            201902L
+# if !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_format)
+// #   define __cpp_lib_format                             201907L
+# endif
+# define __cpp_lib_generic_unordered_lookup             201811L
+# define __cpp_lib_int_pow2                             202002L
+# if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+#   define __cpp_lib_integer_comparison_functions       202002L
+# endif
+# define __cpp_lib_interpolate                          201902L
+# define __cpp_lib_is_constant_evaluated                201811L
+// # define __cpp_lib_is_layout_compatible                 201907L
+# define __cpp_lib_is_nothrow_convertible               201806L
+// # define __cpp_lib_is_pointer_interconvertible          201907L
+# if !defined(_LIBCPP_HAS_NO_THREADS)
+// #   define __cpp_lib_jthread                            201911L
+# endif
+# if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_latch)
+#   define __cpp_lib_latch                              201907L
+# endif
+# define __cpp_lib_list_remove_return_type              201806L
+# if !defined(_LIBCPP_HAS_NO_CONCEPTS)
+#   define __cpp_lib_math_constants                     201907L
+# endif
+// # define __cpp_lib_polymorphic_allocator                201902L
+// # define __cpp_lib_ranges                               201811L
+# define __cpp_lib_remove_cvref                         201711L
+# if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_semaphore)
+#   define __cpp_lib_semaphore                          201907L
+# endif
+# define __cpp_lib_shift                                201806L
+// # define __cpp_lib_smart_ptr_for_overwrite              202002L
+// # define __cpp_lib_source_location                      201907L
+# define __cpp_lib_span                                 202002L
+# define __cpp_lib_ssize                                201902L
+# define __cpp_lib_starts_ends_with                     201711L
+# undef  __cpp_lib_string_view
+# define __cpp_lib_string_view                          201803L
+// # define __cpp_lib_syncbuf                              201803L
+// # define __cpp_lib_three_way_comparison                 201907L
+# define __cpp_lib_to_address                           201711L
+# define __cpp_lib_to_array                             201907L
+# define __cpp_lib_unwrap_ref                           201811L
+#endif
+
+#if _LIBCPP_STD_VER > 20
+# define __cpp_lib_is_scoped_enum                       202011L
+// # define __cpp_lib_stacktrace                           202011L
+// # define __cpp_lib_stdatomic_h                          202011L
+# define __cpp_lib_string_contains                      202011L
+# define __cpp_lib_to_underlying                        202102L
+#endif
+
+// clang-format on
+
+#endif // _LIBCPP_VERSIONH
diff --git a/contrib/libs/cxxsupp/libcxx/include/wchar.h b/contrib/libs/cxxsupp/libcxx/include/wchar.h
new file mode 100644
index 00000000000..10d88dada67
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/wchar.h
@@ -0,0 +1,194 @@
+// -*- C++ -*-
+//===--------------------------- wchar.h ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#if defined(__need_wint_t) || defined(__need_mbstate_t)
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(wchar.h)
+#else
+#include_next <wchar.h>
+#endif
+
+#elif !defined(_LIBCPP_WCHAR_H)
+#define _LIBCPP_WCHAR_H
+
+/*
+    wchar.h synopsis
+
+Macros:
+
+    NULL
+    WCHAR_MAX
+    WCHAR_MIN
+    WEOF
+
+Types:
+
+    mbstate_t
+    size_t
+    tm
+    wint_t
+
+int fwprintf(FILE* restrict stream, const wchar_t* restrict format, ...);
+int fwscanf(FILE* restrict stream, const wchar_t* restrict format, ...);
+int swprintf(wchar_t* restrict s, size_t n, const wchar_t* restrict format, ...);
+int swscanf(const wchar_t* restrict s, const wchar_t* restrict format, ...);
+int vfwprintf(FILE* restrict stream, const wchar_t* restrict format, va_list arg);
+int vfwscanf(FILE* restrict stream, const wchar_t* restrict format, va_list arg);  // C99
+int vswprintf(wchar_t* restrict s, size_t n, const wchar_t* restrict format, va_list arg);
+int vswscanf(const wchar_t* restrict s, const wchar_t* restrict format, va_list arg);  // C99
+int vwprintf(const wchar_t* restrict format, va_list arg);
+int vwscanf(const wchar_t* restrict format, va_list arg);  // C99
+int wprintf(const wchar_t* restrict format, ...);
+int wscanf(const wchar_t* restrict format, ...);
+wint_t fgetwc(FILE* stream);
+wchar_t* fgetws(wchar_t* restrict s, int n, FILE* restrict stream);
+wint_t fputwc(wchar_t c, FILE* stream);
+int fputws(const wchar_t* restrict s, FILE* restrict stream);
+int fwide(FILE* stream, int mode);
+wint_t getwc(FILE* stream);
+wint_t getwchar();
+wint_t putwc(wchar_t c, FILE* stream);
+wint_t putwchar(wchar_t c);
+wint_t ungetwc(wint_t c, FILE* stream);
+double wcstod(const wchar_t* restrict nptr, wchar_t** restrict endptr);
+float wcstof(const wchar_t* restrict nptr, wchar_t** restrict endptr);         // C99
+long double wcstold(const wchar_t* restrict nptr, wchar_t** restrict endptr);  // C99
+long wcstol(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);
+long long wcstoll(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);  // C99
+unsigned long wcstoul(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);
+unsigned long long wcstoull(const wchar_t* restrict nptr, wchar_t** restrict endptr, int base);  // C99
+wchar_t* wcscpy(wchar_t* restrict s1, const wchar_t* restrict s2);
+wchar_t* wcsncpy(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+wchar_t* wcscat(wchar_t* restrict s1, const wchar_t* restrict s2);
+wchar_t* wcsncat(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+int wcscmp(const wchar_t* s1, const wchar_t* s2);
+int wcscoll(const wchar_t* s1, const wchar_t* s2);
+int wcsncmp(const wchar_t* s1, const wchar_t* s2, size_t n);
+size_t wcsxfrm(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+const wchar_t* wcschr(const wchar_t* s, wchar_t c);
+      wchar_t* wcschr(      wchar_t* s, wchar_t c);
+size_t wcscspn(const wchar_t* s1, const wchar_t* s2);
+size_t wcslen(const wchar_t* s);
+const wchar_t* wcspbrk(const wchar_t* s1, const wchar_t* s2);
+      wchar_t* wcspbrk(      wchar_t* s1, const wchar_t* s2);
+const wchar_t* wcsrchr(const wchar_t* s, wchar_t c);
+      wchar_t* wcsrchr(      wchar_t* s, wchar_t c);
+size_t wcsspn(const wchar_t* s1, const wchar_t* s2);
+const wchar_t* wcsstr(const wchar_t* s1, const wchar_t* s2);
+      wchar_t* wcsstr(      wchar_t* s1, const wchar_t* s2);
+wchar_t* wcstok(wchar_t* restrict s1, const wchar_t* restrict s2, wchar_t** restrict ptr);
+const wchar_t* wmemchr(const wchar_t* s, wchar_t c, size_t n);
+      wchar_t* wmemchr(      wchar_t* s, wchar_t c, size_t n);
+int wmemcmp(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+wchar_t* wmemcpy(wchar_t* restrict s1, const wchar_t* restrict s2, size_t n);
+wchar_t* wmemmove(wchar_t* s1, const wchar_t* s2, size_t n);
+wchar_t* wmemset(wchar_t* s, wchar_t c, size_t n);
+size_t wcsftime(wchar_t* restrict s, size_t maxsize, const wchar_t* restrict format,
+                const tm* restrict timeptr);
+wint_t btowc(int c);
+int wctob(wint_t c);
+int mbsinit(const mbstate_t* ps);
+size_t mbrlen(const char* restrict s, size_t n, mbstate_t* restrict ps);
+size_t mbrtowc(wchar_t* restrict pwc, const char* restrict s, size_t n, mbstate_t* restrict ps);
+size_t wcrtomb(char* restrict s, wchar_t wc, mbstate_t* restrict ps);
+size_t mbsrtowcs(wchar_t* restrict dst, const char** restrict src, size_t len,
+                 mbstate_t* restrict ps);
+size_t wcsrtombs(char* restrict dst, const wchar_t** restrict src, size_t len,
+                 mbstate_t* restrict ps);
+
+*/
+
+#include <__config>
+#include <stddef.h>
+
+#if defined(_LIBCPP_HAS_NO_WIDE_CHARACTERS)
+#   error "The <wchar.h> header is not supported since libc++ has been configured with LIBCXX_ENABLE_WIDE_CHARACTERS disabled"
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef __cplusplus
+#define __CORRECT_ISO_CPP_WCHAR_H_PROTO
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#include _LIBCPP_UCRT_INCLUDE(wchar.h)
+#else
+#include_next <wchar.h>
+#endif
+
+// Determine whether we have const-correct overloads for wcschr and friends.
+#if defined(_WCHAR_H_CPLUSPLUS_98_CONFORMANCE_)
+#  define _LIBCPP_WCHAR_H_HAS_CONST_OVERLOADS 1
+#elif defined(__GLIBC_PREREQ)
+#  if __GLIBC_PREREQ(2, 10)
+#    define _LIBCPP_WCHAR_H_HAS_CONST_OVERLOADS 1
+#  endif
+#elif defined(_LIBCPP_MSVCRT)
+#  if defined(_CRT_CONST_CORRECT_OVERLOADS)
+#    define _LIBCPP_WCHAR_H_HAS_CONST_OVERLOADS 1
+#  endif
+#endif
+
+#if defined(__cplusplus) && !defined(_LIBCPP_WCHAR_H_HAS_CONST_OVERLOADS) && defined(_LIBCPP_PREFERRED_OVERLOAD)
+extern "C++" {
+inline _LIBCPP_INLINE_VISIBILITY
+wchar_t* __libcpp_wcschr(const wchar_t* __s, wchar_t __c) {return (wchar_t*)wcschr(__s, __c);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+const wchar_t* wcschr(const wchar_t* __s, wchar_t __c) {return __libcpp_wcschr(__s, __c);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+      wchar_t* wcschr(      wchar_t* __s, wchar_t __c) {return __libcpp_wcschr(__s, __c);}
+
+inline _LIBCPP_INLINE_VISIBILITY
+wchar_t* __libcpp_wcspbrk(const wchar_t* __s1, const wchar_t* __s2) {return (wchar_t*)wcspbrk(__s1, __s2);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+const wchar_t* wcspbrk(const wchar_t* __s1, const wchar_t* __s2) {return __libcpp_wcspbrk(__s1, __s2);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+      wchar_t* wcspbrk(      wchar_t* __s1, const wchar_t* __s2) {return __libcpp_wcspbrk(__s1, __s2);}
+
+inline _LIBCPP_INLINE_VISIBILITY
+wchar_t* __libcpp_wcsrchr(const wchar_t* __s, wchar_t __c) {return (wchar_t*)wcsrchr(__s, __c);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+const wchar_t* wcsrchr(const wchar_t* __s, wchar_t __c) {return __libcpp_wcsrchr(__s, __c);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+      wchar_t* wcsrchr(      wchar_t* __s, wchar_t __c) {return __libcpp_wcsrchr(__s, __c);}
+
+inline _LIBCPP_INLINE_VISIBILITY
+wchar_t* __libcpp_wcsstr(const wchar_t* __s1, const wchar_t* __s2) {return (wchar_t*)wcsstr(__s1, __s2);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+const wchar_t* wcsstr(const wchar_t* __s1, const wchar_t* __s2) {return __libcpp_wcsstr(__s1, __s2);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+      wchar_t* wcsstr(      wchar_t* __s1, const wchar_t* __s2) {return __libcpp_wcsstr(__s1, __s2);}
+
+inline _LIBCPP_INLINE_VISIBILITY
+wchar_t* __libcpp_wmemchr(const wchar_t* __s, wchar_t __c, size_t __n) {return (wchar_t*)wmemchr(__s, __c, __n);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+const wchar_t* wmemchr(const wchar_t* __s, wchar_t __c, size_t __n) {return __libcpp_wmemchr(__s, __c, __n);}
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_PREFERRED_OVERLOAD
+      wchar_t* wmemchr(      wchar_t* __s, wchar_t __c, size_t __n) {return __libcpp_wmemchr(__s, __c, __n);}
+}
+#endif
+
+#if defined(__cplusplus) && (defined(_LIBCPP_MSVCRT_LIKE) || defined(__MVS__))
+extern "C" {
+size_t mbsnrtowcs(wchar_t *__restrict dst, const char **__restrict src,
+                  size_t nmc, size_t len, mbstate_t *__restrict ps);
+size_t wcsnrtombs(char *__restrict dst, const wchar_t **__restrict src,
+                  size_t nwc, size_t len, mbstate_t *__restrict ps);
+}  // extern "C"
+#endif  // __cplusplus && (_LIBCPP_MSVCRT || __MVS__)
+
+#endif // _LIBCPP_WCHAR_H
diff --git a/contrib/libs/cxxsupp/libcxx/include/wctype.h b/contrib/libs/cxxsupp/libcxx/include/wctype.h
new file mode 100644
index 00000000000..e6f813b8b13
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/include/wctype.h
@@ -0,0 +1,99 @@
+// -*- C++ -*-
+//===--------------------------- wctype.h ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_WCTYPE_H
+#define _LIBCPP_WCTYPE_H
+
+/*
+    wctype.h synopsis
+
+Macros:
+
+    WEOF
+
+Types:
+
+    wint_t
+    wctrans_t
+    wctype_t
+
+int iswalnum(wint_t wc);
+int iswalpha(wint_t wc);
+int iswblank(wint_t wc);  // C99
+int iswcntrl(wint_t wc);
+int iswdigit(wint_t wc);
+int iswgraph(wint_t wc);
+int iswlower(wint_t wc);
+int iswprint(wint_t wc);
+int iswpunct(wint_t wc);
+int iswspace(wint_t wc);
+int iswupper(wint_t wc);
+int iswxdigit(wint_t wc);
+int iswctype(wint_t wc, wctype_t desc);
+wctype_t wctype(const char* property);
+wint_t towlower(wint_t wc);
+wint_t towupper(wint_t wc);
+wint_t towctrans(wint_t wc, wctrans_t desc);
+wctrans_t wctrans(const char* property);
+
+*/
+
+#include <__config>
+
+#if defined(_LIBCPP_HAS_NO_WIDE_CHARACTERS)
+#   error "The <wctype.h> header is not supported since libc++ has been configured with LIBCXX_ENABLE_WIDE_CHARACTERS disabled"
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#   include _LIBCPP_UCRT_INCLUDE(wctype.h)
+#   define _LIBCPP_INCLUDED_C_LIBRARY_WCTYPE_H
+#else
+// TODO:
+// In the future, we should unconditionally include_next <wctype.h> here and instead
+// have a mode under which the library does not need libc++'s <wctype.h> or <cwctype>
+// at all (i.e. a mode without wchar_t). As it stands, we need to do that to completely
+// bypass the using declarations in <cwctype> when we did not include <wctype.h>.
+// Otherwise, a using declaration like `using ::wint_t` in <cwctype> will refer to
+// nothing (with using_if_exists), and if we include another header that defines one
+// of these declarations (e.g. <wchar.h>), the second `using ::wint_t` with using_if_exists
+// will fail because it does not refer to the same declaration.
+#if __has_include_next(<wctype.h>)
+#   include_next <wctype.h>
+#   define _LIBCPP_INCLUDED_C_LIBRARY_WCTYPE_H
+#endif
+#endif
+
+#ifdef __cplusplus
+
+#undef iswalnum
+#undef iswalpha
+#undef iswblank
+#undef iswcntrl
+#undef iswdigit
+#undef iswgraph
+#undef iswlower
+#undef iswprint
+#undef iswpunct
+#undef iswspace
+#undef iswupper
+#undef iswxdigit
+#undef iswctype
+#undef wctype
+#undef towlower
+#undef towupper
+#undef towctrans
+#undef wctrans
+
+#endif // __cplusplus
+
+#endif // _LIBCPP_WCTYPE_H
diff --git a/contrib/libs/cxxsupp/libcxx/src/algorithm.cpp b/contrib/libs/cxxsupp/libcxx/src/algorithm.cpp
new file mode 100644
index 00000000000..16221f4b751
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/algorithm.cpp
@@ -0,0 +1,51 @@
+//===----------------------- algorithm.cpp --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "algorithm"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template void __sort<__less<char>&, char*>(char*, char*, __less<char>&);
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template void __sort<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&);
+#endif
+template void __sort<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&);
+template void __sort<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&);
+template void __sort<__less<short>&, short*>(short*, short*, __less<short>&);
+template void __sort<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&);
+template void __sort<__less<int>&, int*>(int*, int*, __less<int>&);
+template void __sort<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&);
+template void __sort<__less<long>&, long*>(long*, long*, __less<long>&);
+template void __sort<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&);
+template void __sort<__less<long long>&, long long*>(long long*, long long*, __less<long long>&);
+template void __sort<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&);
+template void __sort<__less<float>&, float*>(float*, float*, __less<float>&);
+template void __sort<__less<double>&, double*>(double*, double*, __less<double>&);
+template void __sort<__less<long double>&, long double*>(long double*, long double*, __less<long double>&);
+
+template bool __insertion_sort_incomplete<__less<char>&, char*>(char*, char*, __less<char>&);
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template bool __insertion_sort_incomplete<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&);
+#endif
+template bool __insertion_sort_incomplete<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&);
+template bool __insertion_sort_incomplete<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&);
+template bool __insertion_sort_incomplete<__less<short>&, short*>(short*, short*, __less<short>&);
+template bool __insertion_sort_incomplete<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&);
+template bool __insertion_sort_incomplete<__less<int>&, int*>(int*, int*, __less<int>&);
+template bool __insertion_sort_incomplete<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&);
+template bool __insertion_sort_incomplete<__less<long>&, long*>(long*, long*, __less<long>&);
+template bool __insertion_sort_incomplete<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&);
+template bool __insertion_sort_incomplete<__less<long long>&, long long*>(long long*, long long*, __less<long long>&);
+template bool __insertion_sort_incomplete<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&);
+template bool __insertion_sort_incomplete<__less<float>&, float*>(float*, float*, __less<float>&);
+template bool __insertion_sort_incomplete<__less<double>&, double*>(double*, double*, __less<double>&);
+template bool __insertion_sort_incomplete<__less<long double>&, long double*>(long double*, long double*, __less<long double>&);
+
+template unsigned __sort5<__less<long double>&, long double*>(long double*, long double*, long double*, long double*, long double*, __less<long double>&);
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/any.cpp b/contrib/libs/cxxsupp/libcxx/src/any.cpp
new file mode 100644
index 00000000000..415d23b0c94
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/any.cpp
@@ -0,0 +1,34 @@
+//===---------------------------- any.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "any"
+
+namespace std {
+const char* bad_any_cast::what() const noexcept {
+    return "bad any cast";
+}
+}
+
+
+#include <experimental/__config>
+
+//  Preserve std::experimental::any_bad_cast for ABI compatibility
+//  Even though it no longer exists in a header file
+_LIBCPP_BEGIN_NAMESPACE_LFTS
+
+class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_BAD_ANY_CAST bad_any_cast : public bad_cast
+{
+public:
+    virtual const char* what() const noexcept;
+};
+
+const char* bad_any_cast::what() const noexcept {
+    return "bad any cast";
+}
+
+_LIBCPP_END_NAMESPACE_LFTS
diff --git a/contrib/libs/cxxsupp/libcxx/src/atomic.cpp b/contrib/libs/cxxsupp/libcxx/src/atomic.cpp
new file mode 100644
index 00000000000..9ae1fb5199b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/atomic.cpp
@@ -0,0 +1,193 @@
+//===------------------------- atomic.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <__config>
+#ifndef _LIBCPP_HAS_NO_THREADS
+
+#include <climits>
+#include <atomic>
+#include <functional>
+
+#ifdef __linux__
+
+#include <unistd.h>
+#include <linux/futex.h>
+#include <sys/syscall.h>
+
+// libc++ uses SYS_futex as a universal syscall name. However, on 32 bit architectures
+// with a 64 bit time_t, we need to specify SYS_futex_time64.
+#if !defined(SYS_futex) && defined(SYS_futex_time64)
+# define SYS_futex SYS_futex_time64
+#endif
+
+#else // <- Add other operating systems here
+
+// Baseline needs no new headers
+
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifdef __linux__
+
+static void __libcpp_platform_wait_on_address(__cxx_atomic_contention_t const volatile* __ptr,
+                                              __cxx_contention_t __val)
+{
+    static constexpr timespec __timeout = { 2, 0 };
+    syscall(SYS_futex, __ptr, FUTEX_WAIT_PRIVATE, __val, &__timeout, 0, 0);
+}
+
+static void __libcpp_platform_wake_by_address(__cxx_atomic_contention_t const volatile* __ptr,
+                                              bool __notify_one)
+{
+    syscall(SYS_futex, __ptr, FUTEX_WAKE_PRIVATE, __notify_one ? 1 : INT_MAX, 0, 0, 0);
+}
+
+#elif defined(__APPLE__) && defined(_LIBCPP_USE_ULOCK)
+
+extern "C" int __ulock_wait(uint32_t operation, void *addr, uint64_t value,
+		uint32_t timeout); /* timeout is specified in microseconds */
+extern "C" int __ulock_wake(uint32_t operation, void *addr, uint64_t wake_value);
+
+#define UL_COMPARE_AND_WAIT				1
+#define ULF_WAKE_ALL					0x00000100
+
+static void __libcpp_platform_wait_on_address(__cxx_atomic_contention_t const volatile* __ptr,
+                                              __cxx_contention_t __val)
+{
+    __ulock_wait(UL_COMPARE_AND_WAIT,
+                 const_cast<__cxx_atomic_contention_t*>(__ptr), __val, 0);
+}
+
+static void __libcpp_platform_wake_by_address(__cxx_atomic_contention_t const volatile* __ptr,
+                                              bool __notify_one)
+{
+    __ulock_wake(UL_COMPARE_AND_WAIT | (__notify_one ? 0 : ULF_WAKE_ALL),
+                 const_cast<__cxx_atomic_contention_t*>(__ptr), 0);
+}
+
+#else // <- Add other operating systems here
+
+// Baseline is just a timed backoff
+
+static void __libcpp_platform_wait_on_address(__cxx_atomic_contention_t const volatile* __ptr,
+                                              __cxx_contention_t __val)
+{
+    __libcpp_thread_poll_with_backoff([=]() -> bool {
+        return !__cxx_nonatomic_compare_equal(__cxx_atomic_load(__ptr, memory_order_relaxed), __val);
+    }, __libcpp_timed_backoff_policy());
+}
+
+static void __libcpp_platform_wake_by_address(__cxx_atomic_contention_t const volatile*, bool) { }
+
+#endif // __linux__
+
+static constexpr size_t __libcpp_contention_table_size = (1 << 8);  /* < there's no magic in this number */
+
+struct alignas(64) /*  aim to avoid false sharing */ __libcpp_contention_table_entry
+{
+    __cxx_atomic_contention_t __contention_state;
+    __cxx_atomic_contention_t __platform_state;
+    inline constexpr __libcpp_contention_table_entry() :
+        __contention_state(0), __platform_state(0) { }
+};
+
+static __libcpp_contention_table_entry __libcpp_contention_table[ __libcpp_contention_table_size ];
+
+static hash<void const volatile*> __libcpp_contention_hasher;
+
+static __libcpp_contention_table_entry* __libcpp_contention_state(void const volatile * p)
+{
+    return &__libcpp_contention_table[__libcpp_contention_hasher(p) & (__libcpp_contention_table_size - 1)];
+}
+
+/* Given an atomic to track contention and an atomic to actually wait on, which may be
+   the same atomic, we try to detect contention to avoid spuriously calling the platform. */
+
+static void __libcpp_contention_notify(__cxx_atomic_contention_t volatile* __contention_state,
+                                       __cxx_atomic_contention_t const volatile* __platform_state,
+                                       bool __notify_one)
+{
+    if(0 != __cxx_atomic_load(__contention_state, memory_order_seq_cst))
+        // We only call 'wake' if we consumed a contention bit here.
+        __libcpp_platform_wake_by_address(__platform_state, __notify_one);
+}
+static __cxx_contention_t __libcpp_contention_monitor_for_wait(__cxx_atomic_contention_t volatile* __contention_state,
+                                                               __cxx_atomic_contention_t const volatile* __platform_state)
+{
+    // We will monitor this value.
+    return __cxx_atomic_load(__platform_state, memory_order_acquire);
+}
+static void __libcpp_contention_wait(__cxx_atomic_contention_t volatile* __contention_state,
+                                     __cxx_atomic_contention_t const volatile* __platform_state,
+                                     __cxx_contention_t __old_value)
+{
+    __cxx_atomic_fetch_add(__contention_state, __cxx_contention_t(1), memory_order_seq_cst);
+    // We sleep as long as the monitored value hasn't changed.
+    __libcpp_platform_wait_on_address(__platform_state, __old_value);
+    __cxx_atomic_fetch_sub(__contention_state, __cxx_contention_t(1), memory_order_release);
+}
+
+/* When the incoming atomic is the wrong size for the platform wait size, need to
+   launder the value sequence through an atomic from our table. */
+
+static void __libcpp_atomic_notify(void const volatile* __location)
+{
+    auto const __entry = __libcpp_contention_state(__location);
+    // The value sequence laundering happens on the next line below.
+    __cxx_atomic_fetch_add(&__entry->__platform_state, __cxx_contention_t(1), memory_order_release);
+    __libcpp_contention_notify(&__entry->__contention_state,
+                               &__entry->__platform_state,
+                               false /* when laundering, we can't handle notify_one */);
+}
+_LIBCPP_EXPORTED_FROM_ABI
+void __cxx_atomic_notify_one(void const volatile* __location)
+    { __libcpp_atomic_notify(__location); }
+_LIBCPP_EXPORTED_FROM_ABI
+void __cxx_atomic_notify_all(void const volatile* __location)
+    { __libcpp_atomic_notify(__location); }
+_LIBCPP_EXPORTED_FROM_ABI
+__cxx_contention_t __libcpp_atomic_monitor(void const volatile* __location)
+{
+    auto const __entry = __libcpp_contention_state(__location);
+    return __libcpp_contention_monitor_for_wait(&__entry->__contention_state, &__entry->__platform_state);
+}
+_LIBCPP_EXPORTED_FROM_ABI
+void __libcpp_atomic_wait(void const volatile* __location, __cxx_contention_t __old_value)
+{
+    auto const __entry = __libcpp_contention_state(__location);
+    __libcpp_contention_wait(&__entry->__contention_state, &__entry->__platform_state, __old_value);
+}
+
+/* When the incoming atomic happens to be the platform wait size, we still need to use the
+   table for the contention detection, but we can use the atomic directly for the wait. */
+
+_LIBCPP_EXPORTED_FROM_ABI
+void __cxx_atomic_notify_one(__cxx_atomic_contention_t const volatile* __location)
+{
+    __libcpp_contention_notify(&__libcpp_contention_state(__location)->__contention_state, __location, true);
+}
+_LIBCPP_EXPORTED_FROM_ABI
+void __cxx_atomic_notify_all(__cxx_atomic_contention_t const volatile* __location)
+{
+    __libcpp_contention_notify(&__libcpp_contention_state(__location)->__contention_state, __location, false);
+}
+_LIBCPP_EXPORTED_FROM_ABI
+__cxx_contention_t __libcpp_atomic_monitor(__cxx_atomic_contention_t const volatile* __location)
+{
+    return __libcpp_contention_monitor_for_wait(&__libcpp_contention_state(__location)->__contention_state, __location);
+}
+_LIBCPP_EXPORTED_FROM_ABI
+void __libcpp_atomic_wait(__cxx_atomic_contention_t const volatile* __location, __cxx_contention_t __old_value)
+{
+    __libcpp_contention_wait(&__libcpp_contention_state(__location)->__contention_state, __location, __old_value);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif //_LIBCPP_HAS_NO_THREADS
diff --git a/contrib/libs/cxxsupp/libcxx/src/barrier.cpp b/contrib/libs/cxxsupp/libcxx/src/barrier.cpp
new file mode 100644
index 00000000000..9ee476993b8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/barrier.cpp
@@ -0,0 +1,97 @@
+//===------------------------- barrier.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <__config>
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+
+#include <barrier>
+#include <thread>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if !defined(_LIBCPP_HAS_NO_TREE_BARRIER) && (_LIBCPP_STD_VER > 11)
+
+class __barrier_algorithm_base {
+public:
+    struct alignas(64) /* naturally-align the heap state */ __state_t
+    {
+        struct {
+            __atomic_base<__barrier_phase_t> __phase = ATOMIC_VAR_INIT(0);
+        } __tickets[64];
+    };
+
+    ptrdiff_t&              __expected;
+    unique_ptr<__state_t[]> __state;
+
+    _LIBCPP_HIDDEN
+    __barrier_algorithm_base(ptrdiff_t& __expected)
+        : __expected(__expected)
+    {
+        size_t const __count = (__expected + 1) >> 1;
+        __state = unique_ptr<__state_t[]>(new __state_t[__count]);
+    }
+    _LIBCPP_HIDDEN
+    bool __arrive(__barrier_phase_t __old_phase)
+    {
+        __barrier_phase_t const __half_step = __old_phase + 1,
+                                __full_step = __old_phase + 2;
+        size_t __current_expected = __expected,
+            __current = hash<thread::id>()(this_thread::get_id()) % ((__expected + 1) >> 1);
+        for(int __round = 0;; ++__round) {
+            if(__current_expected <= 1)
+                return true;
+            size_t const __end_node = ((__current_expected + 1) >> 1),
+                         __last_node = __end_node - 1;
+            for(;;++__current) {
+                if(__current == __end_node)
+                __current = 0;
+                __barrier_phase_t expect = __old_phase;
+                if(__current == __last_node && (__current_expected & 1))
+                {
+                    if(__state[__current].__tickets[__round].__phase.compare_exchange_strong(expect, __full_step, memory_order_acq_rel))
+                        break;    // I'm 1 in 1, go to next __round
+                }
+                else if(__state[__current].__tickets[__round].__phase.compare_exchange_strong(expect, __half_step, memory_order_acq_rel))
+                {
+                    return false; // I'm 1 in 2, done with arrival
+                }
+                else if(expect == __half_step)
+                {
+                    if(__state[__current].__tickets[__round].__phase.compare_exchange_strong(expect, __full_step, memory_order_acq_rel))
+                        break;    // I'm 2 in 2, go to next __round
+                }
+            }
+            __current_expected = __last_node + 1;
+            __current >>= 1;
+        }
+    }
+};
+
+_LIBCPP_EXPORTED_FROM_ABI
+__barrier_algorithm_base * __construct_barrier_algorithm_base(ptrdiff_t& __expected)
+{
+    return new __barrier_algorithm_base(__expected);
+}
+_LIBCPP_EXPORTED_FROM_ABI
+bool __arrive_barrier_algorithm_base(__barrier_algorithm_base* __barrier,
+                                     __barrier_phase_t __old_phase)
+{
+    return __barrier->__arrive(__old_phase);
+}
+_LIBCPP_EXPORTED_FROM_ABI
+void __destroy_barrier_algorithm_base(__barrier_algorithm_base* __barrier)
+{
+    delete __barrier;
+}
+
+#endif //!defined(_LIBCPP_HAS_NO_TREE_BARRIER) && (_LIBCPP_STD_VER >= 11)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif //_LIBCPP_HAS_NO_THREADS
diff --git a/contrib/libs/cxxsupp/libcxx/src/bind.cpp b/contrib/libs/cxxsupp/libcxx/src/bind.cpp
new file mode 100644
index 00000000000..53efdf9df37
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/bind.cpp
@@ -0,0 +1,29 @@
+//===-------------------------- bind.cpp ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "functional"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace placeholders
+{
+
+const __ph<1>   _1{};
+const __ph<2>   _2{};
+const __ph<3>   _3{};
+const __ph<4>   _4{};
+const __ph<5>   _5{};
+const __ph<6>   _6{};
+const __ph<7>   _7{};
+const __ph<8>   _8{};
+const __ph<9>   _9{};
+const __ph<10> _10{};
+
+}  // placeholders
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/charconv.cpp b/contrib/libs/cxxsupp/libcxx/src/charconv.cpp
new file mode 100644
index 00000000000..78439f96831
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/charconv.cpp
@@ -0,0 +1,160 @@
+//===------------------------- charconv.cpp -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "charconv"
+#include <string.h>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace __itoa
+{
+
+static constexpr char cDigitsLut[200] = {
+    '0', '0', '0', '1', '0', '2', '0', '3', '0', '4', '0', '5', '0', '6', '0',
+    '7', '0', '8', '0', '9', '1', '0', '1', '1', '1', '2', '1', '3', '1', '4',
+    '1', '5', '1', '6', '1', '7', '1', '8', '1', '9', '2', '0', '2', '1', '2',
+    '2', '2', '3', '2', '4', '2', '5', '2', '6', '2', '7', '2', '8', '2', '9',
+    '3', '0', '3', '1', '3', '2', '3', '3', '3', '4', '3', '5', '3', '6', '3',
+    '7', '3', '8', '3', '9', '4', '0', '4', '1', '4', '2', '4', '3', '4', '4',
+    '4', '5', '4', '6', '4', '7', '4', '8', '4', '9', '5', '0', '5', '1', '5',
+    '2', '5', '3', '5', '4', '5', '5', '5', '6', '5', '7', '5', '8', '5', '9',
+    '6', '0', '6', '1', '6', '2', '6', '3', '6', '4', '6', '5', '6', '6', '6',
+    '7', '6', '8', '6', '9', '7', '0', '7', '1', '7', '2', '7', '3', '7', '4',
+    '7', '5', '7', '6', '7', '7', '7', '8', '7', '9', '8', '0', '8', '1', '8',
+    '2', '8', '3', '8', '4', '8', '5', '8', '6', '8', '7', '8', '8', '8', '9',
+    '9', '0', '9', '1', '9', '2', '9', '3', '9', '4', '9', '5', '9', '6', '9',
+    '7', '9', '8', '9', '9'};
+
+template <typename T>
+inline _LIBCPP_INLINE_VISIBILITY char*
+append1(char* buffer, T i) noexcept
+{
+    *buffer = '0' + static_cast<char>(i);
+    return buffer + 1;
+}
+
+template <typename T>
+inline _LIBCPP_INLINE_VISIBILITY char*
+append2(char* buffer, T i) noexcept
+{
+    memcpy(buffer, &cDigitsLut[(i)*2], 2);
+    return buffer + 2;
+}
+
+template <typename T>
+inline _LIBCPP_INLINE_VISIBILITY char*
+append3(char* buffer, T i) noexcept
+{
+    return append2(append1(buffer, (i) / 100), (i) % 100);
+}
+
+template <typename T>
+inline _LIBCPP_INLINE_VISIBILITY char*
+append4(char* buffer, T i) noexcept
+{
+    return append2(append2(buffer, (i) / 100), (i) % 100);
+}
+
+template <typename T>
+inline _LIBCPP_INLINE_VISIBILITY char*
+append2_no_zeros(char* buffer, T v) noexcept
+{
+    if (v < 10)
+        return append1(buffer, v);
+    else
+        return append2(buffer, v);
+}
+
+template <typename T>
+inline _LIBCPP_INLINE_VISIBILITY char*
+append4_no_zeros(char* buffer, T v) noexcept
+{
+    if (v < 100)
+        return append2_no_zeros(buffer, v);
+    else if (v < 1000)
+        return append3(buffer, v);
+    else
+        return append4(buffer, v);
+}
+
+template <typename T>
+inline _LIBCPP_INLINE_VISIBILITY char*
+append8_no_zeros(char* buffer, T v) noexcept
+{
+    if (v < 10000)
+    {
+        buffer = append4_no_zeros(buffer, v);
+    }
+    else
+    {
+        buffer = append4_no_zeros(buffer, v / 10000);
+        buffer = append4(buffer, v % 10000);
+    }
+    return buffer;
+}
+
+char*
+__u32toa(uint32_t value, char* buffer) noexcept
+{
+    if (value < 100000000)
+    {
+        buffer = append8_no_zeros(buffer, value);
+    }
+    else
+    {
+        // value = aabbbbcccc in decimal
+        const uint32_t a = value / 100000000;  // 1 to 42
+        value %= 100000000;
+
+        buffer = append2_no_zeros(buffer, a);
+        buffer = append4(buffer, value / 10000);
+        buffer = append4(buffer, value % 10000);
+    }
+
+    return buffer;
+}
+
+char*
+__u64toa(uint64_t value, char* buffer) noexcept
+{
+    if (value < 100000000)
+    {
+        uint32_t v = static_cast<uint32_t>(value);
+        buffer = append8_no_zeros(buffer, v);
+    }
+    else if (value < 10000000000000000)
+    {
+        const uint32_t v0 = static_cast<uint32_t>(value / 100000000);
+        const uint32_t v1 = static_cast<uint32_t>(value % 100000000);
+
+        buffer = append8_no_zeros(buffer, v0);
+        buffer = append4(buffer, v1 / 10000);
+        buffer = append4(buffer, v1 % 10000);
+    }
+    else
+    {
+        const uint32_t a =
+            static_cast<uint32_t>(value / 10000000000000000);  // 1 to 1844
+        value %= 10000000000000000;
+
+        buffer = append4_no_zeros(buffer, a);
+
+        const uint32_t v0 = static_cast<uint32_t>(value / 100000000);
+        const uint32_t v1 = static_cast<uint32_t>(value % 100000000);
+        buffer = append4(buffer, v0 / 10000);
+        buffer = append4(buffer, v0 % 10000);
+        buffer = append4(buffer, v1 / 10000);
+        buffer = append4(buffer, v1 % 10000);
+    }
+
+    return buffer;
+}
+
+}  // namespace __itoa
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/chrono.cpp b/contrib/libs/cxxsupp/libcxx/src/chrono.cpp
new file mode 100644
index 00000000000..b18e4f7cb9b
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/chrono.cpp
@@ -0,0 +1,298 @@
+//===------------------------- chrono.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#if defined(__MVS__)
+// As part of monotonic clock support on z/OS we need macro _LARGE_TIME_API
+// to be defined before any system header to include definition of struct timespec64.
+#define _LARGE_TIME_API
+#endif
+
+#include "chrono"
+#include "cerrno"        // errno
+#include "system_error"  // __throw_system_error
+
+#if defined(__MVS__)
+#include <__support/ibm/gettod_zos.h> // gettimeofdayMonotonic
+#endif
+
+#include <time.h>        // clock_gettime and CLOCK_{MONOTONIC,REALTIME,MONOTONIC_RAW}
+#include "include/apple_availability.h"
+
+#if __has_include(<unistd.h>)
+# include <unistd.h>
+#endif
+
+#if __has_include(<sys/time.h>)
+# include <sys/time.h> // for gettimeofday and timeval
+#endif
+
+#if !defined(__APPLE__) && defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0
+# define _LIBCPP_USE_CLOCK_GETTIME
+#endif
+
+#if defined(_LIBCPP_WIN32API)
+#  define WIN32_LEAN_AND_MEAN
+#  define VC_EXTRA_LEAN
+#  include <windows.h>
+#  if _WIN32_WINNT >= _WIN32_WINNT_WIN8
+#    include <winapifamily.h>
+#  endif
+#endif // defined(_LIBCPP_WIN32API)
+
+#if __has_include(<mach/mach_time.h>)
+# include <mach/mach_time.h>
+#endif
+
+#if defined(__ELF__) && defined(_LIBCPP_LINK_RT_LIB)
+#  pragma comment(lib, "rt")
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace chrono
+{
+
+//
+// system_clock
+//
+
+#if defined(_LIBCPP_WIN32API)
+
+#if _WIN32_WINNT < _WIN32_WINNT_WIN8
+
+namespace {
+
+typedef void(WINAPI *GetSystemTimeAsFileTimePtr)(LPFILETIME);
+
+class GetSystemTimeInit {
+public:
+  GetSystemTimeInit() {
+    fp = (GetSystemTimeAsFileTimePtr)GetProcAddress(
+        GetModuleHandleW(L"kernel32.dll"), "GetSystemTimePreciseAsFileTime");
+    if (fp == nullptr)
+      fp = GetSystemTimeAsFileTime;
+  }
+  GetSystemTimeAsFileTimePtr fp;
+};
+
+#ifndef _LIBCPP_COMPILER_MSVC
+# 83 "chrono.cpp" 1 3
+#endif
+GetSystemTimeInit GetSystemTimeAsFileTimeFunc _LIBCPP_INIT_PRIORITY_MAX;
+#ifndef _LIBCPP_COMPILER_MSVC
+# 85 "chrono.cpp" 2
+#endif
+} // namespace
+
+#endif
+
+static system_clock::time_point __libcpp_system_clock_now() {
+  // FILETIME is in 100ns units
+  using filetime_duration =
+      _VSTD::chrono::duration<__int64,
+                              _VSTD::ratio_multiply<_VSTD::ratio<100, 1>,
+                                                    nanoseconds::period>>;
+
+  // The Windows epoch is Jan 1 1601, the Unix epoch Jan 1 1970.
+  static _LIBCPP_CONSTEXPR const seconds nt_to_unix_epoch{11644473600};
+
+  FILETIME ft;
+#if (_WIN32_WINNT >= _WIN32_WINNT_WIN8 && WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)) || \
+    (_WIN32_WINNT >= _WIN32_WINNT_WIN10)
+  GetSystemTimePreciseAsFileTime(&ft);
+#elif !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+  GetSystemTimeAsFileTime(&ft);
+#else
+  GetSystemTimeAsFileTimeFunc.fp(&ft);
+#endif
+
+  filetime_duration d{(static_cast<__int64>(ft.dwHighDateTime) << 32) |
+                       static_cast<__int64>(ft.dwLowDateTime)};
+  return system_clock::time_point(duration_cast<system_clock::duration>(d - nt_to_unix_epoch));
+}
+
+#elif defined(CLOCK_REALTIME) && defined(_LIBCPP_USE_CLOCK_GETTIME)
+
+static system_clock::time_point __libcpp_system_clock_now() {
+  struct timespec tp;
+  if (0 != clock_gettime(CLOCK_REALTIME, &tp))
+    __throw_system_error(errno, "clock_gettime(CLOCK_REALTIME) failed");
+  return system_clock::time_point(seconds(tp.tv_sec) + microseconds(tp.tv_nsec / 1000));
+}
+
+#else
+
+static system_clock::time_point __libcpp_system_clock_now() {
+    timeval tv;
+    gettimeofday(&tv, 0);
+    return system_clock::time_point(seconds(tv.tv_sec) + microseconds(tv.tv_usec));
+}
+
+#endif
+
+const bool system_clock::is_steady;
+
+system_clock::time_point
+system_clock::now() noexcept
+{
+    return __libcpp_system_clock_now();
+}
+
+time_t
+system_clock::to_time_t(const time_point& t) noexcept
+{
+    return time_t(duration_cast<seconds>(t.time_since_epoch()).count());
+}
+
+system_clock::time_point
+system_clock::from_time_t(time_t t) noexcept
+{
+    return system_clock::time_point(seconds(t));
+}
+
+//
+// steady_clock
+//
+// Warning:  If this is not truly steady, then it is non-conforming.  It is
+//  better for it to not exist and have the rest of libc++ use system_clock
+//  instead.
+//
+
+#ifndef _LIBCPP_HAS_NO_MONOTONIC_CLOCK
+
+#if defined(__APPLE__)
+
+// TODO(ldionne):
+// This old implementation of steady_clock is retained until Chrome drops supports
+// for macOS < 10.12. The issue is that they link libc++ statically into their
+// application, which means that libc++ must support being built for such deployment
+// targets. See https://llvm.org/D74489 for details.
+#if (defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101200) || \
+    (defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ < 100000) || \
+    (defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ < 100000) || \
+    (defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__) && __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ < 30000)
+# define _LIBCPP_USE_OLD_MACH_ABSOLUTE_TIME
+#endif
+
+#if defined(_LIBCPP_USE_OLD_MACH_ABSOLUTE_TIME)
+
+//   mach_absolute_time() * MachInfo.numer / MachInfo.denom is the number of
+//   nanoseconds since the computer booted up.  MachInfo.numer and MachInfo.denom
+//   are run time constants supplied by the OS.  This clock has no relationship
+//   to the Gregorian calendar.  It's main use is as a high resolution timer.
+
+// MachInfo.numer / MachInfo.denom is often 1 on the latest equipment.  Specialize
+//   for that case as an optimization.
+
+static steady_clock::rep steady_simplified() {
+    return static_cast<steady_clock::rep>(mach_absolute_time());
+}
+static double compute_steady_factor() {
+    mach_timebase_info_data_t MachInfo;
+    mach_timebase_info(&MachInfo);
+    return static_cast<double>(MachInfo.numer) / MachInfo.denom;
+}
+
+static steady_clock::rep steady_full() {
+    static const double factor = compute_steady_factor();
+    return static_cast<steady_clock::rep>(mach_absolute_time() * factor);
+}
+
+typedef steady_clock::rep (*FP)();
+
+static FP init_steady_clock() {
+    mach_timebase_info_data_t MachInfo;
+    mach_timebase_info(&MachInfo);
+    if (MachInfo.numer == MachInfo.denom)
+        return &steady_simplified;
+    return &steady_full;
+}
+
+static steady_clock::time_point __libcpp_steady_clock_now() {
+    static FP fp = init_steady_clock();
+    return steady_clock::time_point(steady_clock::duration(fp()));
+}
+
+#else // vvvvv default behavior for Apple platforms  vvvvv
+
+// On Apple platforms, only CLOCK_UPTIME_RAW, CLOCK_MONOTONIC_RAW or
+// mach_absolute_time are able to time functions in the nanosecond range.
+// Furthermore, only CLOCK_MONOTONIC_RAW is truly monotonic, because it
+// also counts cycles when the system is asleep. Thus, it is the only
+// acceptable implementation of steady_clock.
+static steady_clock::time_point __libcpp_steady_clock_now() {
+    struct timespec tp;
+    if (0 != clock_gettime(CLOCK_MONOTONIC_RAW, &tp))
+        __throw_system_error(errno, "clock_gettime(CLOCK_MONOTONIC_RAW) failed");
+    return steady_clock::time_point(seconds(tp.tv_sec) + nanoseconds(tp.tv_nsec));
+}
+
+#endif
+
+#elif defined(_LIBCPP_WIN32API)
+
+// https://msdn.microsoft.com/en-us/library/windows/desktop/ms644905(v=vs.85).aspx says:
+//    If the function fails, the return value is zero. <snip>
+//    On systems that run Windows XP or later, the function will always succeed
+//      and will thus never return zero.
+
+static LARGE_INTEGER
+__QueryPerformanceFrequency()
+{
+    LARGE_INTEGER val;
+    (void) QueryPerformanceFrequency(&val);
+    return val;
+}
+
+static steady_clock::time_point __libcpp_steady_clock_now() {
+  static const LARGE_INTEGER freq = __QueryPerformanceFrequency();
+
+  LARGE_INTEGER counter;
+  (void) QueryPerformanceCounter(&counter);
+  auto seconds = counter.QuadPart / freq.QuadPart;
+  auto fractions = counter.QuadPart % freq.QuadPart;
+  auto dur = seconds * nano::den + fractions * nano::den / freq.QuadPart;
+  return steady_clock::time_point(steady_clock::duration(dur));
+}
+
+#elif defined(__MVS__)
+
+static steady_clock::time_point __libcpp_steady_clock_now() {
+  struct timespec64 ts;
+  if (0 != gettimeofdayMonotonic(&ts))
+    __throw_system_error(errno, "failed to obtain time of day");
+
+  return steady_clock::time_point(seconds(ts.tv_sec) + nanoseconds(ts.tv_nsec));
+}
+
+#elif defined(CLOCK_MONOTONIC)
+
+static steady_clock::time_point __libcpp_steady_clock_now() {
+    struct timespec tp;
+    if (0 != clock_gettime(CLOCK_MONOTONIC, &tp))
+        __throw_system_error(errno, "clock_gettime(CLOCK_MONOTONIC) failed");
+    return steady_clock::time_point(seconds(tp.tv_sec) + nanoseconds(tp.tv_nsec));
+}
+
+#else
+#   error "Monotonic clock not implemented on this platform"
+#endif
+
+const bool steady_clock::is_steady;
+
+steady_clock::time_point
+steady_clock::now() noexcept
+{
+    return __libcpp_steady_clock_now();
+}
+
+#endif // !_LIBCPP_HAS_NO_MONOTONIC_CLOCK
+
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/condition_variable.cpp b/contrib/libs/cxxsupp/libcxx/src/condition_variable.cpp
new file mode 100644
index 00000000000..1e29083e6e1
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/condition_variable.cpp
@@ -0,0 +1,93 @@
+//===-------------------- condition_variable.cpp --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "__config"
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+
+#include "condition_variable"
+#include "thread"
+#include "system_error"
+#include "__undef_macros"
+
+#if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
+#pragma comment(lib, "pthread")
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// ~condition_variable is defined elsewhere.
+
+void
+condition_variable::notify_one() noexcept
+{
+    __libcpp_condvar_signal(&__cv_);
+}
+
+void
+condition_variable::notify_all() noexcept
+{
+    __libcpp_condvar_broadcast(&__cv_);
+}
+
+void
+condition_variable::wait(unique_lock<mutex>& lk) noexcept
+{
+    if (!lk.owns_lock())
+        __throw_system_error(EPERM,
+                                  "condition_variable::wait: mutex not locked");
+    int ec = __libcpp_condvar_wait(&__cv_, lk.mutex()->native_handle());
+    if (ec)
+        __throw_system_error(ec, "condition_variable wait failed");
+}
+
+void
+condition_variable::__do_timed_wait(unique_lock<mutex>& lk,
+     chrono::time_point<chrono::system_clock, chrono::nanoseconds> tp) noexcept
+{
+    using namespace chrono;
+    if (!lk.owns_lock())
+        __throw_system_error(EPERM,
+                            "condition_variable::timed wait: mutex not locked");
+    nanoseconds d = tp.time_since_epoch();
+    if (d > nanoseconds(0x59682F000000E941))
+        d = nanoseconds(0x59682F000000E941);
+    __libcpp_timespec_t ts;
+    seconds s = duration_cast<seconds>(d);
+    typedef decltype(ts.tv_sec) ts_sec;
+    _LIBCPP_CONSTEXPR ts_sec ts_sec_max = numeric_limits<ts_sec>::max();
+    if (s.count() < ts_sec_max)
+    {
+        ts.tv_sec = static_cast<ts_sec>(s.count());
+        ts.tv_nsec = static_cast<decltype(ts.tv_nsec)>((d - s).count());
+    }
+    else
+    {
+        ts.tv_sec = ts_sec_max;
+        ts.tv_nsec = giga::num - 1;
+    }
+    int ec = __libcpp_condvar_timedwait(&__cv_, lk.mutex()->native_handle(), &ts);
+    if (ec != 0 && ec != ETIMEDOUT)
+        __throw_system_error(ec, "condition_variable timed_wait failed");
+}
+
+void
+notify_all_at_thread_exit(condition_variable& cond, unique_lock<mutex> lk)
+{
+    auto& tl_ptr = __thread_local_data();
+    // If this thread was not created using std::thread then it will not have
+    // previously allocated.
+    if (tl_ptr.get() == nullptr) {
+        tl_ptr.set_pointer(new __thread_struct);
+    }
+    __thread_local_data()->notify_all_at_thread_exit(&cond, lk.release());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !_LIBCPP_HAS_NO_THREADS
diff --git a/contrib/libs/cxxsupp/libcxx/src/condition_variable_destructor.cpp b/contrib/libs/cxxsupp/libcxx/src/condition_variable_destructor.cpp
new file mode 100644
index 00000000000..44fa240ba78
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/condition_variable_destructor.cpp
@@ -0,0 +1,46 @@
+//===---------------- condition_variable_destructor.cpp ------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// Define ~condition_variable.
+//
+// On some platforms ~condition_variable has been made trivial and the
+// definition is only provided for ABI compatibility.
+
+#include "__config"
+#include "__threading_support"
+
+#if !defined(_LIBCPP_HAS_NO_THREADS)
+# if _LIBCPP_ABI_VERSION == 1 || !defined(_LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION)
+#   define NEEDS_CONDVAR_DESTRUCTOR
+# endif
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifdef NEEDS_CONDVAR_DESTRUCTOR
+
+class _LIBCPP_TYPE_VIS condition_variable
+{
+    __libcpp_condvar_t __cv_ = _LIBCPP_CONDVAR_INITIALIZER;
+public:
+    _LIBCPP_INLINE_VISIBILITY
+    constexpr condition_variable() noexcept = default;
+
+    ~condition_variable();
+
+    condition_variable(const condition_variable&) = delete;
+    condition_variable& operator=(const condition_variable&)  = delete;
+};
+
+condition_variable::~condition_variable()
+{
+    __libcpp_condvar_destroy(&__cv_);
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/debug.cpp b/contrib/libs/cxxsupp/libcxx/src/debug.cpp
new file mode 100644
index 00000000000..dd5963fcce1
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/debug.cpp
@@ -0,0 +1,578 @@
+//===-------------------------- debug.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "__config"
+#include "__debug"
+#include "functional"
+#include "algorithm"
+#include "string"
+#include "cstdio"
+#include "__hash_table"
+#ifndef _LIBCPP_HAS_NO_THREADS
+#include "mutex"
+#if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
+#pragma comment(lib, "pthread")
+#endif
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+std::string __libcpp_debug_info::what() const {
+  string msg = __file_;
+  msg += ":" + to_string(__line_) + ": _LIBCPP_ASSERT '";
+  msg += __pred_;
+  msg += "' failed. ";
+  msg += __msg_;
+  return msg;
+}
+_LIBCPP_NORETURN void __libcpp_abort_debug_function(__libcpp_debug_info const& info) {
+    std::fprintf(stderr, "%s\n", info.what().c_str());
+    std::abort();
+}
+
+_LIBCPP_SAFE_STATIC __libcpp_debug_function_type
+    __libcpp_debug_function = __libcpp_abort_debug_function;
+
+bool __libcpp_set_debug_function(__libcpp_debug_function_type __func) {
+  __libcpp_debug_function = __func;
+  return true;
+}
+
+_LIBCPP_FUNC_VIS
+__libcpp_db*
+__get_db()
+{
+    static _LIBCPP_NO_DESTROY __libcpp_db db;
+    return &db;
+}
+
+_LIBCPP_FUNC_VIS
+const __libcpp_db*
+__get_const_db()
+{
+    return __get_db();
+}
+
+namespace
+{
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+typedef mutex mutex_type;
+typedef lock_guard<mutex_type> WLock;
+typedef lock_guard<mutex_type> RLock;
+
+mutex_type&
+mut()
+{
+    static _LIBCPP_NO_DESTROY mutex_type m;
+    return m;
+}
+#endif // !_LIBCPP_HAS_NO_THREADS
+
+}  // unnamed namespace
+
+__i_node::~__i_node()
+{
+    if (__next_)
+    {
+        __next_->~__i_node();
+        free(__next_);
+    }
+}
+
+__c_node::~__c_node()
+{
+    free(beg_);
+    if (__next_)
+    {
+        __next_->~__c_node();
+        free(__next_);
+    }
+}
+
+__libcpp_db::__libcpp_db()
+    : __cbeg_(nullptr),
+      __cend_(nullptr),
+      __csz_(0),
+      __ibeg_(nullptr),
+      __iend_(nullptr),
+      __isz_(0)
+{
+}
+
+__libcpp_db::~__libcpp_db()
+{
+    if (__cbeg_)
+    {
+        for (__c_node** p = __cbeg_; p != __cend_; ++p)
+        {
+            if (*p != nullptr)
+            {
+                (*p)->~__c_node();
+                free(*p);
+            }
+        }
+        free(__cbeg_);
+    }
+    if (__ibeg_)
+    {
+        for (__i_node** p = __ibeg_; p != __iend_; ++p)
+        {
+            if (*p != nullptr)
+            {
+                (*p)->~__i_node();
+                free(*p);
+            }
+        }
+        free(__ibeg_);
+    }
+}
+
+void*
+__libcpp_db::__find_c_from_i(void* __i) const
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    RLock _(mut());
+#endif
+    __i_node* i = __find_iterator(__i);
+    _LIBCPP_ASSERT(i != nullptr, "iterator not found in debug database.");
+    return i->__c_ != nullptr ? i->__c_->__c_ : nullptr;
+}
+
+void
+__libcpp_db::__insert_ic(void* __i, const void* __c)
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    WLock _(mut());
+#endif
+    if (__cbeg_ == __cend_)
+        return;
+    size_t hc = hash<const void*>()(__c) % static_cast<size_t>(__cend_ - __cbeg_);
+    __c_node* c = __cbeg_[hc];
+    if (c == nullptr)
+        return;
+    while (c->__c_ != __c)
+    {
+        c = c->__next_;
+        if (c == nullptr)
+            return;
+    }
+    __i_node* i = __insert_iterator(__i);
+    c->__add(i);
+    i->__c_ = c;
+}
+
+void
+__libcpp_db::__insert_c(void* __c, __libcpp_db::_InsertConstruct *__fn)
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    WLock _(mut());
+#endif
+    if (__csz_ + 1 > static_cast<size_t>(__cend_ - __cbeg_))
+    {
+        size_t nc = __next_prime(2*static_cast<size_t>(__cend_ - __cbeg_) + 1);
+        __c_node** cbeg = static_cast<__c_node**>(calloc(nc, sizeof(__c_node*)));
+        if (cbeg == nullptr)
+            __throw_bad_alloc();
+
+        for (__c_node** p = __cbeg_; p != __cend_; ++p)
+        {
+            __c_node* q = *p;
+            while (q != nullptr)
+            {
+                size_t h = hash<void*>()(q->__c_) % nc;
+                __c_node* r = q->__next_;
+                q->__next_ = cbeg[h];
+                cbeg[h] = q;
+                q = r;
+            }
+        }
+        free(__cbeg_);
+        __cbeg_ = cbeg;
+        __cend_ = __cbeg_ + nc;
+    }
+    size_t hc = hash<void*>()(__c) % static_cast<size_t>(__cend_ - __cbeg_);
+    __c_node* p = __cbeg_[hc];
+    void *buf = malloc(sizeof(__c_node));
+    if (buf == nullptr)
+      __throw_bad_alloc();
+    __cbeg_[hc] = __fn(buf, __c, p);
+
+    ++__csz_;
+}
+
+void
+__libcpp_db::__erase_i(void* __i)
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    WLock _(mut());
+#endif
+    if (__ibeg_ != __iend_)
+    {
+        size_t hi = hash<void*>()(__i) % static_cast<size_t>(__iend_ - __ibeg_);
+        __i_node* p = __ibeg_[hi];
+        if (p != nullptr)
+        {
+            __i_node* q = nullptr;
+            while (p->__i_ != __i)
+            {
+                q = p;
+                p = p->__next_;
+                if (p == nullptr)
+                    return;
+            }
+            if (q == nullptr)
+                __ibeg_[hi] = p->__next_;
+            else
+                q->__next_ = p->__next_;
+            __c_node* c = p->__c_;
+            --__isz_;
+            if (c != nullptr)
+                c->__remove(p);
+            free(p);
+        }
+    }
+}
+
+void
+__libcpp_db::__invalidate_all(void* __c)
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    WLock _(mut());
+#endif
+    if (__cend_ != __cbeg_)
+    {
+        size_t hc = hash<void*>()(__c) % static_cast<size_t>(__cend_ - __cbeg_);
+        __c_node* p = __cbeg_[hc];
+        if (p == nullptr)
+            return;
+        while (p->__c_ != __c)
+        {
+            p = p->__next_;
+            if (p == nullptr)
+                return;
+        }
+        while (p->end_ != p->beg_)
+        {
+            --p->end_;
+            (*p->end_)->__c_ = nullptr;
+        }
+    }
+}
+
+__c_node*
+__libcpp_db::__find_c_and_lock(void* __c) const
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    mut().lock();
+#endif
+    if (__cend_ == __cbeg_)
+    {
+#ifndef _LIBCPP_HAS_NO_THREADS
+        mut().unlock();
+#endif
+        return nullptr;
+    }
+    size_t hc = hash<void*>()(__c) % static_cast<size_t>(__cend_ - __cbeg_);
+    __c_node* p = __cbeg_[hc];
+    if (p == nullptr)
+    {
+#ifndef _LIBCPP_HAS_NO_THREADS
+        mut().unlock();
+#endif
+        return nullptr;
+    }
+    while (p->__c_ != __c)
+    {
+        p = p->__next_;
+        if (p == nullptr)
+        {
+#ifndef _LIBCPP_HAS_NO_THREADS
+            mut().unlock();
+#endif
+            return nullptr;
+        }
+    }
+    return p;
+}
+
+__c_node*
+__libcpp_db::__find_c(void* __c) const
+{
+    size_t hc = hash<void*>()(__c) % static_cast<size_t>(__cend_ - __cbeg_);
+    __c_node* p = __cbeg_[hc];
+    _LIBCPP_ASSERT(p != nullptr, "debug mode internal logic error __find_c A");
+    while (p->__c_ != __c)
+    {
+        p = p->__next_;
+        _LIBCPP_ASSERT(p != nullptr, "debug mode internal logic error __find_c B");
+    }
+    return p;
+}
+
+void
+__libcpp_db::unlock() const
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    mut().unlock();
+#endif
+}
+
+void
+__libcpp_db::__erase_c(void* __c)
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    WLock _(mut());
+#endif
+    if (__cend_ != __cbeg_)
+    {
+        size_t hc = hash<void*>()(__c) % static_cast<size_t>(__cend_ - __cbeg_);
+        __c_node* p = __cbeg_[hc];
+        if (p == nullptr)
+            return;
+        __c_node* q = nullptr;
+        _LIBCPP_ASSERT(p != nullptr, "debug mode internal logic error __erase_c A");
+        while (p->__c_ != __c)
+        {
+            q = p;
+            p = p->__next_;
+            if (p == nullptr)
+                return;
+            _LIBCPP_ASSERT(p != nullptr, "debug mode internal logic error __erase_c B");
+        }
+        if (q == nullptr)
+            __cbeg_[hc] = p->__next_;
+        else
+            q->__next_ = p->__next_;
+        while (p->end_ != p->beg_)
+        {
+            --p->end_;
+            (*p->end_)->__c_ = nullptr;
+        }
+        free(p->beg_);
+        free(p);
+        --__csz_;
+    }
+}
+
+void
+__libcpp_db::__iterator_copy(void* __i, const void* __i0)
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    WLock _(mut());
+#endif
+    __i_node* i = __find_iterator(__i);
+    __i_node* i0 = __find_iterator(__i0);
+    __c_node* c0 = i0 != nullptr ? i0->__c_ : nullptr;
+    if (i == nullptr && i0 != nullptr)
+        i = __insert_iterator(__i);
+    __c_node* c = i != nullptr ? i->__c_ : nullptr;
+    if (c != c0)
+    {
+        if (c != nullptr)
+            c->__remove(i);
+        if (i != nullptr)
+        {
+            i->__c_ = nullptr;
+            if (c0 != nullptr)
+            {
+                i->__c_ = c0;
+                i->__c_->__add(i);
+            }
+        }
+    }
+}
+
+bool
+__libcpp_db::__dereferenceable(const void* __i) const
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    RLock _(mut());
+#endif
+    __i_node* i = __find_iterator(__i);
+    return i != nullptr && i->__c_ != nullptr && i->__c_->__dereferenceable(__i);
+}
+
+bool
+__libcpp_db::__decrementable(const void* __i) const
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    RLock _(mut());
+#endif
+    __i_node* i = __find_iterator(__i);
+    return i != nullptr && i->__c_ != nullptr && i->__c_->__decrementable(__i);
+}
+
+bool
+__libcpp_db::__addable(const void* __i, ptrdiff_t __n) const
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    RLock _(mut());
+#endif
+    __i_node* i = __find_iterator(__i);
+    return i != nullptr && i->__c_ != nullptr && i->__c_->__addable(__i, __n);
+}
+
+bool
+__libcpp_db::__subscriptable(const void* __i, ptrdiff_t __n) const
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    RLock _(mut());
+#endif
+    __i_node* i = __find_iterator(__i);
+    return i != nullptr && i->__c_ != nullptr && i->__c_->__subscriptable(__i, __n);
+}
+
+bool
+__libcpp_db::__less_than_comparable(const void* __i, const void* __j) const
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    RLock _(mut());
+#endif
+    __i_node* i = __find_iterator(__i);
+    __i_node* j = __find_iterator(__j);
+    __c_node* ci = i != nullptr ? i->__c_ : nullptr;
+    __c_node* cj = j != nullptr ? j->__c_ : nullptr;
+    return ci == cj;
+}
+
+void
+__libcpp_db::swap(void* c1, void* c2)
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    WLock _(mut());
+#endif
+    size_t hc = hash<void*>()(c1) % static_cast<size_t>(__cend_ - __cbeg_);
+    __c_node* p1 = __cbeg_[hc];
+    _LIBCPP_ASSERT(p1 != nullptr, "debug mode internal logic error swap A");
+    while (p1->__c_ != c1)
+    {
+        p1 = p1->__next_;
+        _LIBCPP_ASSERT(p1 != nullptr, "debug mode internal logic error swap B");
+    }
+    hc = hash<void*>()(c2) % static_cast<size_t>(__cend_ - __cbeg_);
+    __c_node* p2 = __cbeg_[hc];
+    _LIBCPP_ASSERT(p2 != nullptr, "debug mode internal logic error swap C");
+    while (p2->__c_ != c2)
+    {
+        p2 = p2->__next_;
+        _LIBCPP_ASSERT(p2 != nullptr, "debug mode internal logic error swap D");
+    }
+    std::swap(p1->beg_, p2->beg_);
+    std::swap(p1->end_, p2->end_);
+    std::swap(p1->cap_, p2->cap_);
+    for (__i_node** p = p1->beg_; p != p1->end_; ++p)
+        (*p)->__c_ = p1;
+    for (__i_node** p = p2->beg_; p != p2->end_; ++p)
+        (*p)->__c_ = p2;
+}
+
+void
+__libcpp_db::__insert_i(void* __i)
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    WLock _(mut());
+#endif
+    __insert_iterator(__i);
+}
+
+void
+__c_node::__add(__i_node* i)
+{
+    if (end_ == cap_)
+    {
+        size_t nc = 2*static_cast<size_t>(cap_ - beg_);
+        if (nc == 0)
+            nc = 1;
+        __i_node** beg =
+           static_cast<__i_node**>(malloc(nc * sizeof(__i_node*)));
+        if (beg == nullptr)
+            __throw_bad_alloc();
+
+        if (nc > 1)
+            memcpy(beg, beg_, nc/2*sizeof(__i_node*));
+        free(beg_);
+        beg_ = beg;
+        end_ = beg_ + nc/2;
+        cap_ = beg_ + nc;
+    }
+    *end_++ = i;
+}
+
+// private api
+
+_LIBCPP_HIDDEN
+__i_node*
+__libcpp_db::__insert_iterator(void* __i)
+{
+    if (__isz_ + 1 > static_cast<size_t>(__iend_ - __ibeg_))
+    {
+        size_t nc = __next_prime(2*static_cast<size_t>(__iend_ - __ibeg_) + 1);
+        __i_node** ibeg = static_cast<__i_node**>(calloc(nc, sizeof(__i_node*)));
+        if (ibeg == nullptr)
+            __throw_bad_alloc();
+
+        for (__i_node** p = __ibeg_; p != __iend_; ++p)
+        {
+            __i_node* q = *p;
+            while (q != nullptr)
+            {
+                size_t h = hash<void*>()(q->__i_) % nc;
+                __i_node* r = q->__next_;
+                q->__next_ = ibeg[h];
+                ibeg[h] = q;
+                q = r;
+            }
+        }
+        free(__ibeg_);
+        __ibeg_ = ibeg;
+        __iend_ = __ibeg_ + nc;
+    }
+    size_t hi = hash<void*>()(__i) % static_cast<size_t>(__iend_ - __ibeg_);
+    __i_node* p = __ibeg_[hi];
+    __i_node* r = __ibeg_[hi] =
+      static_cast<__i_node*>(malloc(sizeof(__i_node)));
+    if (r == nullptr)
+        __throw_bad_alloc();
+
+    ::new(r) __i_node(__i, p, nullptr);
+    ++__isz_;
+    return r;
+}
+
+_LIBCPP_HIDDEN
+__i_node*
+__libcpp_db::__find_iterator(const void* __i) const
+{
+    __i_node* r = nullptr;
+    if (__ibeg_ != __iend_)
+    {
+        size_t h = hash<const void*>()(__i) % static_cast<size_t>(__iend_ - __ibeg_);
+        for (__i_node* nd = __ibeg_[h]; nd != nullptr; nd = nd->__next_)
+        {
+            if (nd->__i_ == __i)
+            {
+                r = nd;
+                break;
+            }
+        }
+    }
+    return r;
+}
+
+_LIBCPP_HIDDEN
+void
+__c_node::__remove(__i_node* p)
+{
+    __i_node** r = find(beg_, end_, p);
+    _LIBCPP_ASSERT(r != end_, "debug mode internal logic error __c_node::__remove");
+    if (--end_ != r)
+        memmove(r, r+1, static_cast<size_t>(end_ - r)*sizeof(__i_node*));
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/exception.cpp b/contrib/libs/cxxsupp/libcxx/src/exception.cpp
new file mode 100644
index 00000000000..cc732883778
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/exception.cpp
@@ -0,0 +1,34 @@
+//===------------------------ exception.cpp -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "exception"
+#include "new"
+#include "typeinfo"
+
+#if defined(LIBCXX_BUILDING_LIBCXXRT) || defined(LIBCXX_BUILDING_LIBCXXABI)
+  #include <cxxabi.h>
+  using namespace __cxxabiv1;
+  #define HAVE_DEPENDENT_EH_ABI 1
+#endif
+
+#if defined(_LIBCPP_ABI_MICROSOFT)
+#include "support/runtime/exception_msvc.ipp"
+#include "support/runtime/exception_pointer_msvc.ipp"
+#elif defined(_LIBCPPABI_VERSION)
+#include "support/runtime/exception_libcxxabi.ipp"
+#include "support/runtime/exception_pointer_cxxabi.ipp"
+#elif defined(LIBCXX_BUILDING_LIBCXXRT)
+#include "support/runtime/exception_libcxxrt.ipp"
+#include "support/runtime/exception_pointer_cxxabi.ipp"
+#elif defined(__GLIBCXX__)
+#include "support/runtime/exception_glibcxx.ipp"
+#include "support/runtime/exception_pointer_glibcxx.ipp"
+#else
+#include "support/runtime/exception_fallback.ipp"
+#include "support/runtime/exception_pointer_unimplemented.ipp"
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/src/experimental/memory_resource.cpp b/contrib/libs/cxxsupp/libcxx/src/experimental/memory_resource.cpp
new file mode 100644
index 00000000000..5f9d3b8a4cb
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/experimental/memory_resource.cpp
@@ -0,0 +1,148 @@
+//===------------------------ memory_resource.cpp -------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "experimental/memory_resource"
+
+#ifndef _LIBCPP_HAS_NO_ATOMIC_HEADER
+#include "atomic"
+#elif !defined(_LIBCPP_HAS_NO_THREADS)
+#include "mutex"
+#if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
+#pragma comment(lib, "pthread")
+#endif
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_LFTS_PMR
+
+// memory_resource
+
+//memory_resource::~memory_resource() {}
+
+// new_delete_resource()
+
+class _LIBCPP_TYPE_VIS __new_delete_memory_resource_imp
+    : public memory_resource
+{
+    void *do_allocate(size_t size, size_t align) override {
+#ifdef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
+        if (__is_overaligned_for_new(align))
+            __throw_bad_alloc();
+#endif
+        return _VSTD::__libcpp_allocate(size, align);
+    }
+
+    void do_deallocate(void *p, size_t n, size_t align) override {
+      _VSTD::__libcpp_deallocate(p, n, align);
+    }
+
+    bool do_is_equal(memory_resource const & other) const noexcept override
+        { return &other == this; }
+
+public:
+    ~__new_delete_memory_resource_imp() override = default;
+};
+
+// null_memory_resource()
+
+class _LIBCPP_TYPE_VIS __null_memory_resource_imp
+    : public memory_resource
+{
+public:
+    ~__null_memory_resource_imp() = default;
+
+protected:
+    virtual void* do_allocate(size_t, size_t) {
+        __throw_bad_alloc();
+    }
+    virtual void do_deallocate(void *, size_t, size_t) {}
+    virtual bool do_is_equal(memory_resource const & __other) const noexcept
+    { return &__other == this; }
+};
+
+namespace {
+
+union ResourceInitHelper {
+  struct {
+    __new_delete_memory_resource_imp new_delete_res;
+    __null_memory_resource_imp       null_res;
+  } resources;
+  char dummy;
+  _LIBCPP_CONSTEXPR_AFTER_CXX11 ResourceInitHelper() : resources() {}
+  ~ResourceInitHelper() {}
+};
+
+# 79 "memory_resource.cpp" 1 3
+_LIBCPP_SAFE_STATIC ResourceInitHelper res_init _LIBCPP_INIT_PRIORITY_MAX;
+# 81 "memory_resource.cpp" 2
+
+} // end namespace
+
+
+memory_resource * new_delete_resource() noexcept {
+    return &res_init.resources.new_delete_res;
+}
+
+memory_resource * null_memory_resource() noexcept {
+    return &res_init.resources.null_res;
+}
+
+// default_memory_resource()
+
+static memory_resource *
+__default_memory_resource(bool set = false, memory_resource * new_res = nullptr) noexcept
+{
+#ifndef _LIBCPP_HAS_NO_ATOMIC_HEADER
+    _LIBCPP_SAFE_STATIC static atomic<memory_resource*> __res =
+        ATOMIC_VAR_INIT(&res_init.resources.new_delete_res);
+    if (set) {
+        new_res = new_res ? new_res : new_delete_resource();
+        // TODO: Can a weaker ordering be used?
+        return _VSTD::atomic_exchange_explicit(
+            &__res, new_res, memory_order_acq_rel);
+    }
+    else {
+        return _VSTD::atomic_load_explicit(
+            &__res, memory_order_acquire);
+    }
+#elif !defined(_LIBCPP_HAS_NO_THREADS)
+    _LIBCPP_SAFE_STATIC static memory_resource * res = &res_init.resources.new_delete_res;
+    static mutex res_lock;
+    if (set) {
+        new_res = new_res ? new_res : new_delete_resource();
+        lock_guard<mutex> guard(res_lock);
+        memory_resource * old_res = res;
+        res = new_res;
+        return old_res;
+    } else {
+        lock_guard<mutex> guard(res_lock);
+        return res;
+    }
+#else
+    _LIBCPP_SAFE_STATIC static memory_resource* res = &res_init.resources.new_delete_res;
+    if (set) {
+        new_res = new_res ? new_res : new_delete_resource();
+        memory_resource * old_res = res;
+        res = new_res;
+        return old_res;
+    } else {
+        return res;
+    }
+#endif
+}
+
+memory_resource * get_default_resource() noexcept
+{
+    return __default_memory_resource();
+}
+
+memory_resource * set_default_resource(memory_resource * __new_res) noexcept
+{
+    return __default_memory_resource(true, __new_res);
+}
+
+_LIBCPP_END_NAMESPACE_LFTS_PMR
diff --git a/contrib/libs/cxxsupp/libcxx/src/filesystem/directory_iterator.cpp b/contrib/libs/cxxsupp/libcxx/src/filesystem/directory_iterator.cpp
new file mode 100644
index 00000000000..a098dd163b9
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/filesystem/directory_iterator.cpp
@@ -0,0 +1,415 @@
+//===------------------ directory_iterator.cpp ----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "filesystem"
+#include "__config"
+#if defined(_LIBCPP_WIN32API)
+#define WIN32_LEAN_AND_MEAN
+#define NOMINMAX
+#include <windows.h>
+#else
+#include <dirent.h>
+#endif
+#include <errno.h>
+
+#include "filesystem_common.h"
+
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+
+namespace detail {
+namespace {
+
+#if !defined(_LIBCPP_WIN32API)
+
+#if defined(DT_BLK)
+template <class DirEntT, class = decltype(DirEntT::d_type)>
+static file_type get_file_type(DirEntT* ent, int) {
+  switch (ent->d_type) {
+  case DT_BLK:
+    return file_type::block;
+  case DT_CHR:
+    return file_type::character;
+  case DT_DIR:
+    return file_type::directory;
+  case DT_FIFO:
+    return file_type::fifo;
+  case DT_LNK:
+    return file_type::symlink;
+  case DT_REG:
+    return file_type::regular;
+  case DT_SOCK:
+    return file_type::socket;
+  // Unlike in lstat, hitting "unknown" here simply means that the underlying
+  // filesystem doesn't support d_type. Report is as 'none' so we correctly
+  // set the cache to empty.
+  case DT_UNKNOWN:
+    break;
+  }
+  return file_type::none;
+}
+#endif // defined(DT_BLK)
+
+template <class DirEntT>
+static file_type get_file_type(DirEntT*, long) {
+  return file_type::none;
+}
+
+static pair<string_view, file_type> posix_readdir(DIR* dir_stream,
+                                                  error_code& ec) {
+  struct dirent* dir_entry_ptr = nullptr;
+  errno = 0; // zero errno in order to detect errors
+  ec.clear();
+  if ((dir_entry_ptr = ::readdir(dir_stream)) == nullptr) {
+    if (errno)
+      ec = capture_errno();
+    return {};
+  } else {
+    return {dir_entry_ptr->d_name, get_file_type(dir_entry_ptr, 0)};
+  }
+}
+#else
+// defined(_LIBCPP_WIN32API)
+
+static file_type get_file_type(const WIN32_FIND_DATAW& data) {
+  if (data.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT &&
+      data.dwReserved0 == IO_REPARSE_TAG_SYMLINK)
+    return file_type::symlink;
+  if (data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
+    return file_type::directory;
+  return file_type::regular;
+}
+static uintmax_t get_file_size(const WIN32_FIND_DATAW& data) {
+  return (static_cast<uint64_t>(data.nFileSizeHigh) << 32) + data.nFileSizeLow;
+}
+static file_time_type get_write_time(const WIN32_FIND_DATAW& data) {
+  ULARGE_INTEGER tmp;
+  const FILETIME& time = data.ftLastWriteTime;
+  tmp.u.LowPart = time.dwLowDateTime;
+  tmp.u.HighPart = time.dwHighDateTime;
+  return file_time_type(file_time_type::duration(tmp.QuadPart));
+}
+
+#endif
+
+} // namespace
+} // namespace detail
+
+using detail::ErrorHandler;
+
+#if defined(_LIBCPP_WIN32API)
+class __dir_stream {
+public:
+  __dir_stream() = delete;
+  __dir_stream& operator=(const __dir_stream&) = delete;
+
+  __dir_stream(__dir_stream&& __ds) noexcept : __stream_(__ds.__stream_),
+                                               __root_(move(__ds.__root_)),
+                                               __entry_(move(__ds.__entry_)) {
+    __ds.__stream_ = INVALID_HANDLE_VALUE;
+  }
+
+  __dir_stream(const path& root, directory_options opts, error_code& ec)
+      : __stream_(INVALID_HANDLE_VALUE), __root_(root) {
+    if (root.native().empty()) {
+      ec = make_error_code(errc::no_such_file_or_directory);
+      return;
+    }
+    __stream_ = ::FindFirstFileW((root / "*").c_str(), &__data_);
+    if (__stream_ == INVALID_HANDLE_VALUE) {
+      ec = detail::make_windows_error(GetLastError());
+      const bool ignore_permission_denied =
+          bool(opts & directory_options::skip_permission_denied);
+      if (ignore_permission_denied &&
+          ec.value() == static_cast<int>(errc::permission_denied))
+        ec.clear();
+      return;
+    }
+    if (!assign())
+      advance(ec);
+  }
+
+  ~__dir_stream() noexcept {
+    if (__stream_ == INVALID_HANDLE_VALUE)
+      return;
+    close();
+  }
+
+  bool good() const noexcept { return __stream_ != INVALID_HANDLE_VALUE; }
+
+  bool advance(error_code& ec) {
+    while (::FindNextFileW(__stream_, &__data_)) {
+      if (assign())
+        return true;
+    }
+    close();
+    return false;
+  }
+
+  bool assign() {
+    if (!wcscmp(__data_.cFileName, L".") || !wcscmp(__data_.cFileName, L".."))
+      return false;
+    // FIXME: Cache more of this
+    //directory_entry::__cached_data cdata;
+    //cdata.__type_ = get_file_type(__data_);
+    //cdata.__size_ = get_file_size(__data_);
+    //cdata.__write_time_ = get_write_time(__data_);
+    __entry_.__assign_iter_entry(
+        __root_ / __data_.cFileName,
+        directory_entry::__create_iter_result(detail::get_file_type(__data_)));
+    return true;
+  }
+
+private:
+  error_code close() noexcept {
+    error_code ec;
+    if (!::FindClose(__stream_))
+      ec = detail::make_windows_error(GetLastError());
+    __stream_ = INVALID_HANDLE_VALUE;
+    return ec;
+  }
+
+  HANDLE __stream_{INVALID_HANDLE_VALUE};
+  WIN32_FIND_DATAW __data_;
+
+public:
+  path __root_;
+  directory_entry __entry_;
+};
+#else
+class __dir_stream {
+public:
+  __dir_stream() = delete;
+  __dir_stream& operator=(const __dir_stream&) = delete;
+
+  __dir_stream(__dir_stream&& other) noexcept : __stream_(other.__stream_),
+                                                __root_(move(other.__root_)),
+                                                __entry_(move(other.__entry_)) {
+    other.__stream_ = nullptr;
+  }
+
+  __dir_stream(const path& root, directory_options opts, error_code& ec)
+      : __stream_(nullptr), __root_(root) {
+    if ((__stream_ = ::opendir(root.c_str())) == nullptr) {
+      ec = detail::capture_errno();
+      const bool allow_eacess =
+          bool(opts & directory_options::skip_permission_denied);
+      if (allow_eacess && ec.value() == EACCES)
+        ec.clear();
+      return;
+    }
+    advance(ec);
+  }
+
+  ~__dir_stream() noexcept {
+    if (__stream_)
+      close();
+  }
+
+  bool good() const noexcept { return __stream_ != nullptr; }
+
+  bool advance(error_code& ec) {
+    while (true) {
+      auto str_type_pair = detail::posix_readdir(__stream_, ec);
+      auto& str = str_type_pair.first;
+      if (str == "." || str == "..") {
+        continue;
+      } else if (ec || str.empty()) {
+        close();
+        return false;
+      } else {
+        __entry_.__assign_iter_entry(
+            __root_ / str,
+            directory_entry::__create_iter_result(str_type_pair.second));
+        return true;
+      }
+    }
+  }
+
+private:
+  error_code close() noexcept {
+    error_code m_ec;
+    if (::closedir(__stream_) == -1)
+      m_ec = detail::capture_errno();
+    __stream_ = nullptr;
+    return m_ec;
+  }
+
+  DIR* __stream_{nullptr};
+
+public:
+  path __root_;
+  directory_entry __entry_;
+};
+#endif
+
+// directory_iterator
+
+directory_iterator::directory_iterator(const path& p, error_code* ec,
+                                       directory_options opts) {
+  ErrorHandler<void> err("directory_iterator::directory_iterator(...)", ec, &p);
+
+  error_code m_ec;
+  __imp_ = make_shared<__dir_stream>(p, opts, m_ec);
+  if (ec)
+    *ec = m_ec;
+  if (!__imp_->good()) {
+    __imp_.reset();
+    if (m_ec)
+      err.report(m_ec);
+  }
+}
+
+directory_iterator& directory_iterator::__increment(error_code* ec) {
+  _LIBCPP_ASSERT(__imp_, "Attempting to increment an invalid iterator");
+  ErrorHandler<void> err("directory_iterator::operator++()", ec);
+
+  error_code m_ec;
+  if (!__imp_->advance(m_ec)) {
+    path root = move(__imp_->__root_);
+    __imp_.reset();
+    if (m_ec)
+      err.report(m_ec, "at root " PATH_CSTR_FMT, root.c_str());
+  }
+  return *this;
+}
+
+directory_entry const& directory_iterator::__dereference() const {
+  _LIBCPP_ASSERT(__imp_, "Attempting to dereference an invalid iterator");
+  return __imp_->__entry_;
+}
+
+// recursive_directory_iterator
+
+struct recursive_directory_iterator::__shared_imp {
+  stack<__dir_stream> __stack_;
+  directory_options __options_;
+};
+
+recursive_directory_iterator::recursive_directory_iterator(
+    const path& p, directory_options opt, error_code* ec)
+    : __imp_(nullptr), __rec_(true) {
+  ErrorHandler<void> err("recursive_directory_iterator", ec, &p);
+
+  error_code m_ec;
+  __dir_stream new_s(p, opt, m_ec);
+  if (m_ec)
+    err.report(m_ec);
+  if (m_ec || !new_s.good())
+    return;
+
+  __imp_ = make_shared<__shared_imp>();
+  __imp_->__options_ = opt;
+  __imp_->__stack_.push(move(new_s));
+}
+
+void recursive_directory_iterator::__pop(error_code* ec) {
+  _LIBCPP_ASSERT(__imp_, "Popping the end iterator");
+  if (ec)
+    ec->clear();
+  __imp_->__stack_.pop();
+  if (__imp_->__stack_.size() == 0)
+    __imp_.reset();
+  else
+    __advance(ec);
+}
+
+directory_options recursive_directory_iterator::options() const {
+  return __imp_->__options_;
+}
+
+int recursive_directory_iterator::depth() const {
+  return __imp_->__stack_.size() - 1;
+}
+
+const directory_entry& recursive_directory_iterator::__dereference() const {
+  return __imp_->__stack_.top().__entry_;
+}
+
+recursive_directory_iterator&
+recursive_directory_iterator::__increment(error_code* ec) {
+  if (ec)
+    ec->clear();
+  if (recursion_pending()) {
+    if (__try_recursion(ec) || (ec && *ec))
+      return *this;
+  }
+  __rec_ = true;
+  __advance(ec);
+  return *this;
+}
+
+void recursive_directory_iterator::__advance(error_code* ec) {
+  ErrorHandler<void> err("recursive_directory_iterator::operator++()", ec);
+
+  const directory_iterator end_it;
+  auto& stack = __imp_->__stack_;
+  error_code m_ec;
+  while (stack.size() > 0) {
+    if (stack.top().advance(m_ec))
+      return;
+    if (m_ec)
+      break;
+    stack.pop();
+  }
+
+  if (m_ec) {
+    path root = move(stack.top().__root_);
+    __imp_.reset();
+    err.report(m_ec, "at root " PATH_CSTR_FMT, root.c_str());
+  } else {
+    __imp_.reset();
+  }
+}
+
+bool recursive_directory_iterator::__try_recursion(error_code* ec) {
+  ErrorHandler<void> err("recursive_directory_iterator::operator++()", ec);
+
+  bool rec_sym = bool(options() & directory_options::follow_directory_symlink);
+
+  auto& curr_it = __imp_->__stack_.top();
+
+  bool skip_rec = false;
+  error_code m_ec;
+  if (!rec_sym) {
+    file_status st(curr_it.__entry_.__get_sym_ft(&m_ec));
+    if (m_ec && status_known(st))
+      m_ec.clear();
+    if (m_ec || is_symlink(st) || !is_directory(st))
+      skip_rec = true;
+  } else {
+    file_status st(curr_it.__entry_.__get_ft(&m_ec));
+    if (m_ec && status_known(st))
+      m_ec.clear();
+    if (m_ec || !is_directory(st))
+      skip_rec = true;
+  }
+
+  if (!skip_rec) {
+    __dir_stream new_it(curr_it.__entry_.path(), __imp_->__options_, m_ec);
+    if (new_it.good()) {
+      __imp_->__stack_.push(move(new_it));
+      return true;
+    }
+  }
+  if (m_ec) {
+    const bool allow_eacess =
+        bool(__imp_->__options_ & directory_options::skip_permission_denied);
+    if (m_ec.value() == EACCES && allow_eacess) {
+      if (ec)
+        ec->clear();
+    } else {
+      path at_ent = move(curr_it.__entry_.__p_);
+      __imp_.reset();
+      err.report(m_ec, "attempting recursion into " PATH_CSTR_FMT,
+                 at_ent.c_str());
+    }
+  }
+  return false;
+}
+
+_LIBCPP_END_NAMESPACE_FILESYSTEM
diff --git a/contrib/libs/cxxsupp/libcxx/src/filesystem/filesystem_common.h b/contrib/libs/cxxsupp/libcxx/src/filesystem/filesystem_common.h
new file mode 100644
index 00000000000..a5f57497837
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/filesystem/filesystem_common.h
@@ -0,0 +1,535 @@
+//===----------------------------------------------------------------------===////
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===////
+
+#ifndef FILESYSTEM_COMMON_H
+#define FILESYSTEM_COMMON_H
+
+#include "__config"
+#include "array"
+#include "chrono"
+#include "climits"
+#include "cstdarg"
+#include "cstdlib"
+#include "ctime"
+#include "filesystem"
+
+#if !defined(_LIBCPP_WIN32API)
+# include <unistd.h>
+# include <sys/stat.h>
+# include <sys/statvfs.h>
+# include <sys/time.h> // for ::utimes as used in __last_write_time
+# include <fcntl.h>    /* values for fchmodat */
+#endif
+
+#include "../include/apple_availability.h"
+
+#if !defined(__APPLE__)
+// We can use the presence of UTIME_OMIT to detect platforms that provide
+// utimensat.
+#if defined(UTIME_OMIT)
+#define _LIBCPP_USE_UTIMENSAT
+#endif
+#endif
+
+#if defined(__GNUC__) || defined(__clang__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-function"
+#endif
+
+#if defined(_LIBCPP_WIN32API)
+#define PS(x) (L##x)
+#define PATH_CSTR_FMT "\"%ls\""
+#else
+#define PS(x) (x)
+#define PATH_CSTR_FMT "\"%s\""
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+
+namespace detail {
+
+#if defined(_LIBCPP_WIN32API)
+// Non anonymous, to allow access from two translation units.
+errc __win_err_to_errc(int err);
+#endif
+
+namespace {
+
+static _LIBCPP_FORMAT_PRINTF(1, 0) string
+format_string_impl(const char* msg, va_list ap) {
+  array<char, 256> buf;
+
+  va_list apcopy;
+  va_copy(apcopy, ap);
+  int ret = ::vsnprintf(buf.data(), buf.size(), msg, apcopy);
+  va_end(apcopy);
+
+  string result;
+  if (static_cast<size_t>(ret) < buf.size()) {
+    result.assign(buf.data(), static_cast<size_t>(ret));
+  } else {
+  // we did not provide a long enough buffer on our first attempt. The
+  // return value is the number of bytes (excluding the null byte) that are
+  // needed for formatting.
+    size_t size_with_null = static_cast<size_t>(ret) + 1;
+  result.__resize_default_init(size_with_null - 1);
+    ret = ::vsnprintf(&result[0], size_with_null, msg, ap);
+  _LIBCPP_ASSERT(static_cast<size_t>(ret) == (size_with_null - 1), "TODO");
+}
+  return result;
+}
+
+static _LIBCPP_FORMAT_PRINTF(1, 2) string
+format_string(const char* msg, ...) {
+  string ret;
+  va_list ap;
+  va_start(ap, msg);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+  try {
+#endif // _LIBCPP_NO_EXCEPTIONS
+    ret = format_string_impl(msg, ap);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+  } catch (...) {
+    va_end(ap);
+    throw;
+  }
+#endif // _LIBCPP_NO_EXCEPTIONS
+  va_end(ap);
+  return ret;
+}
+
+error_code capture_errno() {
+  _LIBCPP_ASSERT(errno, "Expected errno to be non-zero");
+  return error_code(errno, generic_category());
+}
+
+#if defined(_LIBCPP_WIN32API)
+error_code make_windows_error(int err) {
+  return make_error_code(__win_err_to_errc(err));
+}
+#endif
+
+template <class T>
+T error_value();
+template <>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 void error_value<void>() {}
+template <>
+bool error_value<bool>() {
+  return false;
+}
+#if __SIZEOF_SIZE_T__ != __SIZEOF_LONG_LONG__
+template <>
+size_t error_value<size_t>() {
+  return size_t(-1);
+}
+#endif
+template <>
+uintmax_t error_value<uintmax_t>() {
+  return uintmax_t(-1);
+}
+template <>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 file_time_type error_value<file_time_type>() {
+  return file_time_type::min();
+}
+template <>
+path error_value<path>() {
+  return {};
+}
+
+template <class T>
+struct ErrorHandler {
+  const char* func_name_;
+  error_code* ec_ = nullptr;
+  const path* p1_ = nullptr;
+  const path* p2_ = nullptr;
+
+  ErrorHandler(const char* fname, error_code* ec, const path* p1 = nullptr,
+               const path* p2 = nullptr)
+      : func_name_(fname), ec_(ec), p1_(p1), p2_(p2) {
+    if (ec_)
+      ec_->clear();
+  }
+
+  T report(const error_code& ec) const {
+    if (ec_) {
+      *ec_ = ec;
+      return error_value<T>();
+    }
+    string what = string("in ") + func_name_;
+    switch (bool(p1_) + bool(p2_)) {
+    case 0:
+      __throw_filesystem_error(what, ec);
+    case 1:
+      __throw_filesystem_error(what, *p1_, ec);
+    case 2:
+      __throw_filesystem_error(what, *p1_, *p2_, ec);
+    }
+    _LIBCPP_UNREACHABLE();
+  }
+
+  _LIBCPP_FORMAT_PRINTF(3, 0)
+  void report_impl(const error_code& ec, const char* msg, va_list ap) const {
+    if (ec_) {
+      *ec_ = ec;
+      return;
+    }
+    string what =
+        string("in ") + func_name_ + ": " + format_string_impl(msg, ap);
+    switch (bool(p1_) + bool(p2_)) {
+    case 0:
+      __throw_filesystem_error(what, ec);
+    case 1:
+      __throw_filesystem_error(what, *p1_, ec);
+    case 2:
+      __throw_filesystem_error(what, *p1_, *p2_, ec);
+    }
+    _LIBCPP_UNREACHABLE();
+  }
+
+  _LIBCPP_FORMAT_PRINTF(3, 4)
+  T report(const error_code& ec, const char* msg, ...) const {
+    va_list ap;
+    va_start(ap, msg);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try {
+#endif // _LIBCPP_NO_EXCEPTIONS
+      report_impl(ec, msg, ap);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    } catch (...) {
+      va_end(ap);
+      throw;
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    va_end(ap);
+    return error_value<T>();
+  }
+
+  T report(errc const& err) const {
+    return report(make_error_code(err));
+  }
+
+  _LIBCPP_FORMAT_PRINTF(3, 4)
+  T report(errc const& err, const char* msg, ...) const {
+    va_list ap;
+    va_start(ap, msg);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try {
+#endif // _LIBCPP_NO_EXCEPTIONS
+      report_impl(make_error_code(err), msg, ap);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    } catch (...) {
+      va_end(ap);
+      throw;
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    va_end(ap);
+    return error_value<T>();
+  }
+
+private:
+  ErrorHandler(ErrorHandler const&) = delete;
+  ErrorHandler& operator=(ErrorHandler const&) = delete;
+};
+
+using chrono::duration;
+using chrono::duration_cast;
+
+#if defined(_LIBCPP_WIN32API)
+// Various C runtime versions (UCRT, or the legacy msvcrt.dll used by
+// some mingw toolchains) provide different stat function implementations,
+// with a number of limitations with respect to what we want from the
+// stat function. Instead provide our own (in the anonymous detail namespace
+// in posix_compat.h) which does exactly what we want, along with our own
+// stat structure and flag macros.
+
+struct TimeSpec {
+  int64_t tv_sec;
+  int64_t tv_nsec;
+};
+struct StatT {
+  unsigned st_mode;
+  TimeSpec st_atim;
+  TimeSpec st_mtim;
+  uint64_t st_dev; // FILE_ID_INFO::VolumeSerialNumber
+  struct FileIdStruct {
+    unsigned char id[16]; // FILE_ID_INFO::FileId
+    bool operator==(const FileIdStruct &other) const {
+      for (int i = 0; i < 16; i++)
+        if (id[i] != other.id[i])
+          return false;
+      return true;
+    }
+  } st_ino;
+  uint32_t st_nlink;
+  uintmax_t st_size;
+};
+
+#else
+using TimeSpec = struct timespec;
+using TimeVal = struct timeval;
+using StatT = struct stat;
+#endif
+
+template <class FileTimeT, class TimeT,
+          bool IsFloat = is_floating_point<typename FileTimeT::rep>::value>
+struct time_util_base {
+  using rep = typename FileTimeT::rep;
+  using fs_duration = typename FileTimeT::duration;
+  using fs_seconds = duration<rep>;
+  using fs_nanoseconds = duration<rep, nano>;
+  using fs_microseconds = duration<rep, micro>;
+
+  static constexpr rep max_seconds =
+      duration_cast<fs_seconds>(FileTimeT::duration::max()).count();
+
+  static constexpr rep max_nsec =
+      duration_cast<fs_nanoseconds>(FileTimeT::duration::max() -
+                                    fs_seconds(max_seconds))
+          .count();
+
+  static constexpr rep min_seconds =
+      duration_cast<fs_seconds>(FileTimeT::duration::min()).count();
+
+  static constexpr rep min_nsec_timespec =
+      duration_cast<fs_nanoseconds>(
+          (FileTimeT::duration::min() - fs_seconds(min_seconds)) +
+          fs_seconds(1))
+          .count();
+
+private:
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 fs_duration get_min_nsecs() {
+    return duration_cast<fs_duration>(
+        fs_nanoseconds(min_nsec_timespec) -
+        duration_cast<fs_nanoseconds>(fs_seconds(1)));
+  }
+  // Static assert that these values properly round trip.
+  static_assert(fs_seconds(min_seconds) + get_min_nsecs() ==
+                    FileTimeT::duration::min(),
+                "value doesn't roundtrip");
+
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool check_range() {
+    // This kinda sucks, but it's what happens when we don't have __int128_t.
+    if (sizeof(TimeT) == sizeof(rep)) {
+      typedef duration<long long, ratio<3600 * 24 * 365> > Years;
+      return duration_cast<Years>(fs_seconds(max_seconds)) > Years(250) &&
+             duration_cast<Years>(fs_seconds(min_seconds)) < Years(-250);
+    }
+    return max_seconds >= numeric_limits<TimeT>::max() &&
+           min_seconds <= numeric_limits<TimeT>::min();
+  }
+  static_assert(check_range(), "the representable range is unacceptable small");
+};
+
+template <class FileTimeT, class TimeT>
+struct time_util_base<FileTimeT, TimeT, true> {
+  using rep = typename FileTimeT::rep;
+  using fs_duration = typename FileTimeT::duration;
+  using fs_seconds = duration<rep>;
+  using fs_nanoseconds = duration<rep, nano>;
+  using fs_microseconds = duration<rep, micro>;
+
+  static const rep max_seconds;
+  static const rep max_nsec;
+  static const rep min_seconds;
+  static const rep min_nsec_timespec;
+};
+
+template <class FileTimeT, class TimeT>
+const typename FileTimeT::rep
+    time_util_base<FileTimeT, TimeT, true>::max_seconds =
+        duration_cast<fs_seconds>(FileTimeT::duration::max()).count();
+
+template <class FileTimeT, class TimeT>
+const typename FileTimeT::rep time_util_base<FileTimeT, TimeT, true>::max_nsec =
+    duration_cast<fs_nanoseconds>(FileTimeT::duration::max() -
+                                  fs_seconds(max_seconds))
+        .count();
+
+template <class FileTimeT, class TimeT>
+const typename FileTimeT::rep
+    time_util_base<FileTimeT, TimeT, true>::min_seconds =
+        duration_cast<fs_seconds>(FileTimeT::duration::min()).count();
+
+template <class FileTimeT, class TimeT>
+const typename FileTimeT::rep
+    time_util_base<FileTimeT, TimeT, true>::min_nsec_timespec =
+        duration_cast<fs_nanoseconds>((FileTimeT::duration::min() -
+                                       fs_seconds(min_seconds)) +
+                                      fs_seconds(1))
+            .count();
+
+template <class FileTimeT, class TimeT, class TimeSpecT>
+struct time_util : time_util_base<FileTimeT, TimeT> {
+  using Base = time_util_base<FileTimeT, TimeT>;
+  using Base::max_nsec;
+  using Base::max_seconds;
+  using Base::min_nsec_timespec;
+  using Base::min_seconds;
+
+  using typename Base::fs_duration;
+  using typename Base::fs_microseconds;
+  using typename Base::fs_nanoseconds;
+  using typename Base::fs_seconds;
+
+public:
+  template <class CType, class ChronoType>
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool checked_set(CType* out,
+                                                        ChronoType time) {
+    using Lim = numeric_limits<CType>;
+    if (time > Lim::max() || time < Lim::min())
+      return false;
+    *out = static_cast<CType>(time);
+    return true;
+  }
+
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool is_representable(TimeSpecT tm) {
+    if (tm.tv_sec >= 0) {
+      return tm.tv_sec < max_seconds ||
+             (tm.tv_sec == max_seconds && tm.tv_nsec <= max_nsec);
+    } else if (tm.tv_sec == (min_seconds - 1)) {
+      return tm.tv_nsec >= min_nsec_timespec;
+    } else {
+      return tm.tv_sec >= min_seconds;
+    }
+  }
+
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool is_representable(FileTimeT tm) {
+    auto secs = duration_cast<fs_seconds>(tm.time_since_epoch());
+    auto nsecs = duration_cast<fs_nanoseconds>(tm.time_since_epoch() - secs);
+    if (nsecs.count() < 0) {
+      secs = secs + fs_seconds(1);
+      nsecs = nsecs + fs_seconds(1);
+    }
+    using TLim = numeric_limits<TimeT>;
+    if (secs.count() >= 0)
+      return secs.count() <= TLim::max();
+    return secs.count() >= TLim::min();
+  }
+
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 FileTimeT
+  convert_from_timespec(TimeSpecT tm) {
+    if (tm.tv_sec >= 0 || tm.tv_nsec == 0) {
+      return FileTimeT(fs_seconds(tm.tv_sec) +
+                       duration_cast<fs_duration>(fs_nanoseconds(tm.tv_nsec)));
+    } else { // tm.tv_sec < 0
+      auto adj_subsec = duration_cast<fs_duration>(fs_seconds(1) -
+                                                   fs_nanoseconds(tm.tv_nsec));
+      auto Dur = fs_seconds(tm.tv_sec + 1) - adj_subsec;
+      return FileTimeT(Dur);
+    }
+  }
+
+  template <class SubSecT>
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool
+  set_times_checked(TimeT* sec_out, SubSecT* subsec_out, FileTimeT tp) {
+    auto dur = tp.time_since_epoch();
+    auto sec_dur = duration_cast<fs_seconds>(dur);
+    auto subsec_dur = duration_cast<fs_nanoseconds>(dur - sec_dur);
+    // The tv_nsec and tv_usec fields must not be negative so adjust accordingly
+    if (subsec_dur.count() < 0) {
+      if (sec_dur.count() > min_seconds) {
+        sec_dur = sec_dur - fs_seconds(1);
+        subsec_dur = subsec_dur + fs_seconds(1);
+      } else {
+        subsec_dur = fs_nanoseconds::zero();
+      }
+    }
+    return checked_set(sec_out, sec_dur.count()) &&
+           checked_set(subsec_out, subsec_dur.count());
+  }
+  static _LIBCPP_CONSTEXPR_AFTER_CXX11 bool convert_to_timespec(TimeSpecT& dest,
+                                                                FileTimeT tp) {
+    if (!is_representable(tp))
+      return false;
+    return set_times_checked(&dest.tv_sec, &dest.tv_nsec, tp);
+  }
+};
+
+#if defined(_LIBCPP_WIN32API)
+using fs_time = time_util<file_time_type, int64_t, TimeSpec>;
+#else
+using fs_time = time_util<file_time_type, time_t, TimeSpec>;
+#endif
+
+#if defined(__APPLE__)
+inline TimeSpec extract_mtime(StatT const& st) { return st.st_mtimespec; }
+inline TimeSpec extract_atime(StatT const& st) { return st.st_atimespec; }
+#elif defined(__MVS__)
+inline TimeSpec extract_mtime(StatT const& st) {
+  TimeSpec TS = {st.st_mtime, 0};
+  return TS;
+}
+inline TimeSpec extract_atime(StatT const& st) {
+  TimeSpec TS = {st.st_atime, 0};
+  return TS;
+}
+#elif defined(_AIX)
+inline TimeSpec extract_mtime(StatT const& st) {
+  TimeSpec TS = {st.st_mtime, st.st_mtime_n};
+  return TS;
+}
+inline TimeSpec extract_atime(StatT const& st) {
+  TimeSpec TS = {st.st_atime, st.st_atime_n};
+  return TS;
+}
+#else
+inline TimeSpec extract_mtime(StatT const& st) { return st.st_mtim; }
+inline TimeSpec extract_atime(StatT const& st) { return st.st_atim; }
+#endif
+
+#if !defined(_LIBCPP_WIN32API)
+inline TimeVal make_timeval(TimeSpec const& ts) {
+  using namespace chrono;
+  auto Convert = [](long nsec) {
+    using int_type = decltype(std::declval<TimeVal>().tv_usec);
+    auto dur = duration_cast<microseconds>(nanoseconds(nsec)).count();
+    return static_cast<int_type>(dur);
+  };
+  TimeVal TV = {};
+  TV.tv_sec = ts.tv_sec;
+  TV.tv_usec = Convert(ts.tv_nsec);
+  return TV;
+}
+
+inline bool posix_utimes(const path& p, std::array<TimeSpec, 2> const& TS,
+                  error_code& ec) {
+  TimeVal ConvertedTS[2] = {make_timeval(TS[0]), make_timeval(TS[1])};
+  if (::utimes(p.c_str(), ConvertedTS) == -1) {
+    ec = capture_errno();
+    return true;
+  }
+  return false;
+}
+
+#if defined(_LIBCPP_USE_UTIMENSAT)
+bool posix_utimensat(const path& p, std::array<TimeSpec, 2> const& TS,
+                     error_code& ec) {
+  if (::utimensat(AT_FDCWD, p.c_str(), TS.data(), 0) == -1) {
+    ec = capture_errno();
+    return true;
+  }
+  return false;
+}
+#endif
+
+bool set_file_times(const path& p, std::array<TimeSpec, 2> const& TS,
+                    error_code& ec) {
+#if !defined(_LIBCPP_USE_UTIMENSAT)
+  return posix_utimes(p, TS, ec);
+#else
+  return posix_utimensat(p, TS, ec);
+#endif
+}
+#endif /* !_LIBCPP_WIN32API */
+
+} // namespace
+} // end namespace detail
+
+_LIBCPP_END_NAMESPACE_FILESYSTEM
+
+#endif // FILESYSTEM_COMMON_H
diff --git a/contrib/libs/cxxsupp/libcxx/src/filesystem/int128_builtins.cpp b/contrib/libs/cxxsupp/libcxx/src/filesystem/int128_builtins.cpp
new file mode 100644
index 00000000000..ed531ee145a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/filesystem/int128_builtins.cpp
@@ -0,0 +1,54 @@
+/*===-- int128_builtins.cpp - Implement __muloti4 --------------------------===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ * ===----------------------------------------------------------------------===
+ *
+ * This file implements __muloti4, and is stolen from the compiler_rt library.
+ *
+ * FIXME: we steal and re-compile it into filesystem, which uses __int128_t,
+ * and requires this builtin when sanitized. See llvm.org/PR30643
+ *
+ * ===----------------------------------------------------------------------===
+ */
+#include "__config"
+#include "climits"
+
+#if !defined(_LIBCPP_HAS_NO_INT128)
+
+extern "C" __attribute__((no_sanitize("undefined"))) _LIBCPP_FUNC_VIS
+__int128_t __muloti4(__int128_t a, __int128_t b, int* overflow) {
+  const int N = (int)(sizeof(__int128_t) * CHAR_BIT);
+  const __int128_t MIN = (__int128_t)1 << (N - 1);
+  const __int128_t MAX = ~MIN;
+  *overflow = 0;
+  __int128_t result = a * b;
+  if (a == MIN) {
+    if (b != 0 && b != 1)
+      *overflow = 1;
+    return result;
+  }
+  if (b == MIN) {
+    if (a != 0 && a != 1)
+      *overflow = 1;
+    return result;
+  }
+  __int128_t sa = a >> (N - 1);
+  __int128_t abs_a = (a ^ sa) - sa;
+  __int128_t sb = b >> (N - 1);
+  __int128_t abs_b = (b ^ sb) - sb;
+  if (abs_a < 2 || abs_b < 2)
+    return result;
+  if (sa == sb) {
+    if (abs_a > MAX / abs_b)
+      *overflow = 1;
+  } else {
+    if (abs_a > MIN / -abs_b)
+      *overflow = 1;
+  }
+  return result;
+}
+
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/src/filesystem/operations.cpp b/contrib/libs/cxxsupp/libcxx/src/filesystem/operations.cpp
new file mode 100644
index 00000000000..63593be223e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/filesystem/operations.cpp
@@ -0,0 +1,1997 @@
+//===--------------------- filesystem/ops.cpp -----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "filesystem"
+#include "array"
+#include "iterator"
+#include "string_view"
+#include "type_traits"
+#include "vector"
+#include "cstdlib"
+#include "climits"
+
+#include "filesystem_common.h"
+
+#include "posix_compat.h"
+
+#if defined(_LIBCPP_WIN32API)
+# define WIN32_LEAN_AND_MEAN
+# define NOMINMAX
+# include <windows.h>
+#else
+# include <unistd.h>
+# include <sys/stat.h>
+# include <sys/statvfs.h>
+#endif
+#include <time.h>
+#include <fcntl.h> /* values for fchmodat */
+
+#if __has_include(<sys/sendfile.h>)
+# include <sys/sendfile.h>
+# define _LIBCPP_FILESYSTEM_USE_SENDFILE
+#elif defined(__APPLE__) || __has_include(<copyfile.h>)
+# include <copyfile.h>
+# define _LIBCPP_FILESYSTEM_USE_COPYFILE
+#else
+# include "fstream"
+# define _LIBCPP_FILESYSTEM_USE_FSTREAM
+#endif
+
+#if !defined(CLOCK_REALTIME) && !defined(_LIBCPP_WIN32API)
+# include <sys/time.h> // for gettimeofday and timeval
+#endif
+
+#if defined(__ELF__) && defined(_LIBCPP_LINK_RT_LIB)
+# pragma comment(lib, "rt")
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+
+namespace {
+
+bool isSeparator(path::value_type C) {
+  if (C == '/')
+    return true;
+#if defined(_LIBCPP_WIN32API)
+  if (C == '\\')
+    return true;
+#endif
+  return false;
+}
+
+bool isDriveLetter(path::value_type C) {
+  return (C >= 'a' && C <= 'z') || (C >= 'A' && C <= 'Z');
+}
+
+namespace parser {
+
+using string_view_t = path::__string_view;
+using string_view_pair = pair<string_view_t, string_view_t>;
+using PosPtr = path::value_type const*;
+
+struct PathParser {
+  enum ParserState : unsigned char {
+    // Zero is a special sentinel value used by default constructed iterators.
+    PS_BeforeBegin = path::iterator::_BeforeBegin,
+    PS_InRootName = path::iterator::_InRootName,
+    PS_InRootDir = path::iterator::_InRootDir,
+    PS_InFilenames = path::iterator::_InFilenames,
+    PS_InTrailingSep = path::iterator::_InTrailingSep,
+    PS_AtEnd = path::iterator::_AtEnd
+  };
+
+  const string_view_t Path;
+  string_view_t RawEntry;
+  ParserState State;
+
+private:
+  PathParser(string_view_t P, ParserState State) noexcept : Path(P),
+                                                            State(State) {}
+
+public:
+  PathParser(string_view_t P, string_view_t E, unsigned char S)
+      : Path(P), RawEntry(E), State(static_cast<ParserState>(S)) {
+    // S cannot be '0' or PS_BeforeBegin.
+  }
+
+  static PathParser CreateBegin(string_view_t P) noexcept {
+    PathParser PP(P, PS_BeforeBegin);
+    PP.increment();
+    return PP;
+  }
+
+  static PathParser CreateEnd(string_view_t P) noexcept {
+    PathParser PP(P, PS_AtEnd);
+    return PP;
+  }
+
+  PosPtr peek() const noexcept {
+    auto TkEnd = getNextTokenStartPos();
+    auto End = getAfterBack();
+    return TkEnd == End ? nullptr : TkEnd;
+  }
+
+  void increment() noexcept {
+    const PosPtr End = getAfterBack();
+    const PosPtr Start = getNextTokenStartPos();
+    if (Start == End)
+      return makeState(PS_AtEnd);
+
+    switch (State) {
+    case PS_BeforeBegin: {
+      PosPtr TkEnd = consumeRootName(Start, End);
+      if (TkEnd)
+        return makeState(PS_InRootName, Start, TkEnd);
+    }
+      _LIBCPP_FALLTHROUGH();
+    case PS_InRootName: {
+      PosPtr TkEnd = consumeAllSeparators(Start, End);
+      if (TkEnd)
+        return makeState(PS_InRootDir, Start, TkEnd);
+      else
+        return makeState(PS_InFilenames, Start, consumeName(Start, End));
+    }
+    case PS_InRootDir:
+      return makeState(PS_InFilenames, Start, consumeName(Start, End));
+
+    case PS_InFilenames: {
+      PosPtr SepEnd = consumeAllSeparators(Start, End);
+      if (SepEnd != End) {
+        PosPtr TkEnd = consumeName(SepEnd, End);
+        if (TkEnd)
+          return makeState(PS_InFilenames, SepEnd, TkEnd);
+      }
+      return makeState(PS_InTrailingSep, Start, SepEnd);
+    }
+
+    case PS_InTrailingSep:
+      return makeState(PS_AtEnd);
+
+    case PS_AtEnd:
+      _LIBCPP_UNREACHABLE();
+    }
+  }
+
+  void decrement() noexcept {
+    const PosPtr REnd = getBeforeFront();
+    const PosPtr RStart = getCurrentTokenStartPos() - 1;
+    if (RStart == REnd) // we're decrementing the begin
+      return makeState(PS_BeforeBegin);
+
+    switch (State) {
+    case PS_AtEnd: {
+      // Try to consume a trailing separator or root directory first.
+      if (PosPtr SepEnd = consumeAllSeparators(RStart, REnd)) {
+        if (SepEnd == REnd)
+          return makeState(PS_InRootDir, Path.data(), RStart + 1);
+        PosPtr TkStart = consumeRootName(SepEnd, REnd);
+        if (TkStart == REnd)
+          return makeState(PS_InRootDir, RStart, RStart + 1);
+        return makeState(PS_InTrailingSep, SepEnd + 1, RStart + 1);
+      } else {
+        PosPtr TkStart = consumeRootName(RStart, REnd);
+        if (TkStart == REnd)
+          return makeState(PS_InRootName, TkStart + 1, RStart + 1);
+        TkStart = consumeName(RStart, REnd);
+        return makeState(PS_InFilenames, TkStart + 1, RStart + 1);
+      }
+    }
+    case PS_InTrailingSep:
+      return makeState(PS_InFilenames, consumeName(RStart, REnd) + 1,
+                       RStart + 1);
+    case PS_InFilenames: {
+      PosPtr SepEnd = consumeAllSeparators(RStart, REnd);
+      if (SepEnd == REnd)
+        return makeState(PS_InRootDir, Path.data(), RStart + 1);
+      PosPtr TkStart = consumeRootName(SepEnd ? SepEnd : RStart, REnd);
+      if (TkStart == REnd) {
+        if (SepEnd)
+          return makeState(PS_InRootDir, SepEnd + 1, RStart + 1);
+        return makeState(PS_InRootName, TkStart + 1, RStart + 1);
+      }
+      TkStart = consumeName(SepEnd, REnd);
+      return makeState(PS_InFilenames, TkStart + 1, SepEnd + 1);
+    }
+    case PS_InRootDir:
+      return makeState(PS_InRootName, Path.data(), RStart + 1);
+    case PS_InRootName:
+    case PS_BeforeBegin:
+      _LIBCPP_UNREACHABLE();
+    }
+  }
+
+  /// \brief Return a view with the "preferred representation" of the current
+  ///   element. For example trailing separators are represented as a '.'
+  string_view_t operator*() const noexcept {
+    switch (State) {
+    case PS_BeforeBegin:
+    case PS_AtEnd:
+      return PS("");
+    case PS_InRootDir:
+      if (RawEntry[0] == '\\')
+        return PS("\\");
+      else
+        return PS("/");
+    case PS_InTrailingSep:
+      return PS("");
+    case PS_InRootName:
+    case PS_InFilenames:
+      return RawEntry;
+    }
+    _LIBCPP_UNREACHABLE();
+  }
+
+  explicit operator bool() const noexcept {
+    return State != PS_BeforeBegin && State != PS_AtEnd;
+  }
+
+  PathParser& operator++() noexcept {
+    increment();
+    return *this;
+  }
+
+  PathParser& operator--() noexcept {
+    decrement();
+    return *this;
+  }
+
+  bool atEnd() const noexcept {
+    return State == PS_AtEnd;
+  }
+
+  bool inRootDir() const noexcept {
+    return State == PS_InRootDir;
+  }
+
+  bool inRootName() const noexcept {
+    return State == PS_InRootName;
+  }
+
+  bool inRootPath() const noexcept {
+    return inRootName() || inRootDir();
+  }
+
+private:
+  void makeState(ParserState NewState, PosPtr Start, PosPtr End) noexcept {
+    State = NewState;
+    RawEntry = string_view_t(Start, End - Start);
+  }
+  void makeState(ParserState NewState) noexcept {
+    State = NewState;
+    RawEntry = {};
+  }
+
+  PosPtr getAfterBack() const noexcept { return Path.data() + Path.size(); }
+
+  PosPtr getBeforeFront() const noexcept { return Path.data() - 1; }
+
+  /// \brief Return a pointer to the first character after the currently
+  ///   lexed element.
+  PosPtr getNextTokenStartPos() const noexcept {
+    switch (State) {
+    case PS_BeforeBegin:
+      return Path.data();
+    case PS_InRootName:
+    case PS_InRootDir:
+    case PS_InFilenames:
+      return &RawEntry.back() + 1;
+    case PS_InTrailingSep:
+    case PS_AtEnd:
+      return getAfterBack();
+    }
+    _LIBCPP_UNREACHABLE();
+  }
+
+  /// \brief Return a pointer to the first character in the currently lexed
+  ///   element.
+  PosPtr getCurrentTokenStartPos() const noexcept {
+    switch (State) {
+    case PS_BeforeBegin:
+    case PS_InRootName:
+      return &Path.front();
+    case PS_InRootDir:
+    case PS_InFilenames:
+    case PS_InTrailingSep:
+      return &RawEntry.front();
+    case PS_AtEnd:
+      return &Path.back() + 1;
+    }
+    _LIBCPP_UNREACHABLE();
+  }
+
+  // Consume all consecutive separators.
+  PosPtr consumeAllSeparators(PosPtr P, PosPtr End) const noexcept {
+    if (P == nullptr || P == End || !isSeparator(*P))
+      return nullptr;
+    const int Inc = P < End ? 1 : -1;
+    P += Inc;
+    while (P != End && isSeparator(*P))
+      P += Inc;
+    return P;
+  }
+
+  // Consume exactly N separators, or return nullptr.
+  PosPtr consumeNSeparators(PosPtr P, PosPtr End, int N) const noexcept {
+    PosPtr Ret = consumeAllSeparators(P, End);
+    if (Ret == nullptr)
+      return nullptr;
+    if (P < End) {
+      if (Ret == P + N)
+        return Ret;
+    } else {
+      if (Ret == P - N)
+        return Ret;
+    }
+    return nullptr;
+  }
+
+  PosPtr consumeName(PosPtr P, PosPtr End) const noexcept {
+    PosPtr Start = P;
+    if (P == nullptr || P == End || isSeparator(*P))
+      return nullptr;
+    const int Inc = P < End ? 1 : -1;
+    P += Inc;
+    while (P != End && !isSeparator(*P))
+      P += Inc;
+    if (P == End && Inc < 0) {
+      // Iterating backwards and consumed all the rest of the input.
+      // Check if the start of the string would have been considered
+      // a root name.
+      PosPtr RootEnd = consumeRootName(End + 1, Start);
+      if (RootEnd)
+        return RootEnd - 1;
+    }
+    return P;
+  }
+
+  PosPtr consumeDriveLetter(PosPtr P, PosPtr End) const noexcept {
+    if (P == End)
+      return nullptr;
+    if (P < End) {
+      if (P + 1 == End || !isDriveLetter(P[0]) || P[1] != ':')
+        return nullptr;
+      return P + 2;
+    } else {
+      if (P - 1 == End || !isDriveLetter(P[-1]) || P[0] != ':')
+        return nullptr;
+      return P - 2;
+    }
+  }
+
+  PosPtr consumeNetworkRoot(PosPtr P, PosPtr End) const noexcept {
+    if (P == End)
+      return nullptr;
+    if (P < End)
+      return consumeName(consumeNSeparators(P, End, 2), End);
+    else
+      return consumeNSeparators(consumeName(P, End), End, 2);
+  }
+
+#if defined(_LIBCPP_WIN32API)
+  PosPtr consumeRootName(PosPtr P, PosPtr End) const noexcept {
+    if (PosPtr Ret = consumeDriveLetter(P, End))
+      return Ret;
+    if (PosPtr Ret = consumeNetworkRoot(P, End))
+      return Ret;
+    return nullptr;
+  }
+#else
+  PosPtr consumeRootName(PosPtr /*P*/, PosPtr /*End*/) const noexcept {
+    return nullptr;
+  }
+#endif
+};
+
+string_view_pair separate_filename(string_view_t const& s) {
+  if (s == PS(".") || s == PS("..") || s.empty())
+    return string_view_pair{s, PS("")};
+  auto pos = s.find_last_of('.');
+  if (pos == string_view_t::npos || pos == 0)
+    return string_view_pair{s, string_view_t{}};
+  return string_view_pair{s.substr(0, pos), s.substr(pos)};
+}
+
+string_view_t createView(PosPtr S, PosPtr E) noexcept {
+  return {S, static_cast<size_t>(E - S) + 1};
+}
+
+} // namespace parser
+} // namespace
+
+//                       POSIX HELPERS
+
+#if defined(_LIBCPP_WIN32API)
+namespace detail {
+
+errc __win_err_to_errc(int err) {
+  constexpr struct {
+    DWORD win;
+    errc errc;
+  } win_error_mapping[] = {
+      {ERROR_ACCESS_DENIED, errc::permission_denied},
+      {ERROR_ALREADY_EXISTS, errc::file_exists},
+      {ERROR_BAD_NETPATH, errc::no_such_file_or_directory},
+      {ERROR_BAD_PATHNAME, errc::no_such_file_or_directory},
+      {ERROR_BAD_UNIT, errc::no_such_device},
+      {ERROR_BROKEN_PIPE, errc::broken_pipe},
+      {ERROR_BUFFER_OVERFLOW, errc::filename_too_long},
+      {ERROR_BUSY, errc::device_or_resource_busy},
+      {ERROR_BUSY_DRIVE, errc::device_or_resource_busy},
+      {ERROR_CANNOT_MAKE, errc::permission_denied},
+      {ERROR_CANTOPEN, errc::io_error},
+      {ERROR_CANTREAD, errc::io_error},
+      {ERROR_CANTWRITE, errc::io_error},
+      {ERROR_CURRENT_DIRECTORY, errc::permission_denied},
+      {ERROR_DEV_NOT_EXIST, errc::no_such_device},
+      {ERROR_DEVICE_IN_USE, errc::device_or_resource_busy},
+      {ERROR_DIR_NOT_EMPTY, errc::directory_not_empty},
+      {ERROR_DIRECTORY, errc::invalid_argument},
+      {ERROR_DISK_FULL, errc::no_space_on_device},
+      {ERROR_FILE_EXISTS, errc::file_exists},
+      {ERROR_FILE_NOT_FOUND, errc::no_such_file_or_directory},
+      {ERROR_HANDLE_DISK_FULL, errc::no_space_on_device},
+      {ERROR_INVALID_ACCESS, errc::permission_denied},
+      {ERROR_INVALID_DRIVE, errc::no_such_device},
+      {ERROR_INVALID_FUNCTION, errc::function_not_supported},
+      {ERROR_INVALID_HANDLE, errc::invalid_argument},
+      {ERROR_INVALID_NAME, errc::no_such_file_or_directory},
+      {ERROR_INVALID_PARAMETER, errc::invalid_argument},
+      {ERROR_LOCK_VIOLATION, errc::no_lock_available},
+      {ERROR_LOCKED, errc::no_lock_available},
+      {ERROR_NEGATIVE_SEEK, errc::invalid_argument},
+      {ERROR_NOACCESS, errc::permission_denied},
+      {ERROR_NOT_ENOUGH_MEMORY, errc::not_enough_memory},
+      {ERROR_NOT_READY, errc::resource_unavailable_try_again},
+      {ERROR_NOT_SAME_DEVICE, errc::cross_device_link},
+      {ERROR_NOT_SUPPORTED, errc::not_supported},
+      {ERROR_OPEN_FAILED, errc::io_error},
+      {ERROR_OPEN_FILES, errc::device_or_resource_busy},
+      {ERROR_OPERATION_ABORTED, errc::operation_canceled},
+      {ERROR_OUTOFMEMORY, errc::not_enough_memory},
+      {ERROR_PATH_NOT_FOUND, errc::no_such_file_or_directory},
+      {ERROR_READ_FAULT, errc::io_error},
+      {ERROR_REPARSE_TAG_INVALID, errc::invalid_argument},
+      {ERROR_RETRY, errc::resource_unavailable_try_again},
+      {ERROR_SEEK, errc::io_error},
+      {ERROR_SHARING_VIOLATION, errc::permission_denied},
+      {ERROR_TOO_MANY_OPEN_FILES, errc::too_many_files_open},
+      {ERROR_WRITE_FAULT, errc::io_error},
+      {ERROR_WRITE_PROTECT, errc::permission_denied},
+  };
+
+  for (const auto &pair : win_error_mapping)
+    if (pair.win == static_cast<DWORD>(err))
+      return pair.errc;
+  return errc::invalid_argument;
+}
+
+} // namespace detail
+#endif
+
+namespace detail {
+namespace {
+
+using value_type = path::value_type;
+using string_type = path::string_type;
+
+struct FileDescriptor {
+  const path& name;
+  int fd = -1;
+  StatT m_stat;
+  file_status m_status;
+
+  template <class... Args>
+  static FileDescriptor create(const path* p, error_code& ec, Args... args) {
+    ec.clear();
+    int fd;
+    if ((fd = detail::open(p->c_str(), args...)) == -1) {
+      ec = capture_errno();
+      return FileDescriptor{p};
+    }
+    return FileDescriptor(p, fd);
+  }
+
+  template <class... Args>
+  static FileDescriptor create_with_status(const path* p, error_code& ec,
+                                           Args... args) {
+    FileDescriptor fd = create(p, ec, args...);
+    if (!ec)
+      fd.refresh_status(ec);
+
+    return fd;
+  }
+
+  file_status get_status() const { return m_status; }
+  StatT const& get_stat() const { return m_stat; }
+
+  bool status_known() const { return _VSTD_FS::status_known(m_status); }
+
+  file_status refresh_status(error_code& ec);
+
+  void close() noexcept {
+    if (fd != -1)
+      detail::close(fd);
+    fd = -1;
+  }
+
+  FileDescriptor(FileDescriptor&& other)
+      : name(other.name), fd(other.fd), m_stat(other.m_stat),
+        m_status(other.m_status) {
+    other.fd = -1;
+    other.m_status = file_status{};
+  }
+
+  ~FileDescriptor() { close(); }
+
+  FileDescriptor(FileDescriptor const&) = delete;
+  FileDescriptor& operator=(FileDescriptor const&) = delete;
+
+private:
+  explicit FileDescriptor(const path* p, int fd = -1) : name(*p), fd(fd) {}
+};
+
+perms posix_get_perms(const StatT& st) noexcept {
+  return static_cast<perms>(st.st_mode) & perms::mask;
+}
+
+file_status create_file_status(error_code& m_ec, path const& p,
+                               const StatT& path_stat, error_code* ec) {
+  if (ec)
+    *ec = m_ec;
+  if (m_ec && (m_ec.value() == ENOENT || m_ec.value() == ENOTDIR)) {
+    return file_status(file_type::not_found);
+  } else if (m_ec) {
+    ErrorHandler<void> err("posix_stat", ec, &p);
+    err.report(m_ec, "failed to determine attributes for the specified path");
+    return file_status(file_type::none);
+  }
+  // else
+
+  file_status fs_tmp;
+  auto const mode = path_stat.st_mode;
+  if (S_ISLNK(mode))
+    fs_tmp.type(file_type::symlink);
+  else if (S_ISREG(mode))
+    fs_tmp.type(file_type::regular);
+  else if (S_ISDIR(mode))
+    fs_tmp.type(file_type::directory);
+  else if (S_ISBLK(mode))
+    fs_tmp.type(file_type::block);
+  else if (S_ISCHR(mode))
+    fs_tmp.type(file_type::character);
+  else if (S_ISFIFO(mode))
+    fs_tmp.type(file_type::fifo);
+  else if (S_ISSOCK(mode))
+    fs_tmp.type(file_type::socket);
+  else
+    fs_tmp.type(file_type::unknown);
+
+  fs_tmp.permissions(detail::posix_get_perms(path_stat));
+  return fs_tmp;
+}
+
+file_status posix_stat(path const& p, StatT& path_stat, error_code* ec) {
+  error_code m_ec;
+  if (detail::stat(p.c_str(), &path_stat) == -1)
+    m_ec = detail::capture_errno();
+  return create_file_status(m_ec, p, path_stat, ec);
+}
+
+file_status posix_stat(path const& p, error_code* ec) {
+  StatT path_stat;
+  return posix_stat(p, path_stat, ec);
+}
+
+file_status posix_lstat(path const& p, StatT& path_stat, error_code* ec) {
+  error_code m_ec;
+  if (detail::lstat(p.c_str(), &path_stat) == -1)
+    m_ec = detail::capture_errno();
+  return create_file_status(m_ec, p, path_stat, ec);
+}
+
+file_status posix_lstat(path const& p, error_code* ec) {
+  StatT path_stat;
+  return posix_lstat(p, path_stat, ec);
+}
+
+// http://pubs.opengroup.org/onlinepubs/9699919799/functions/ftruncate.html
+bool posix_ftruncate(const FileDescriptor& fd, off_t to_size, error_code& ec) {
+  if (detail::ftruncate(fd.fd, to_size) == -1) {
+    ec = capture_errno();
+    return true;
+  }
+  ec.clear();
+  return false;
+}
+
+bool posix_fchmod(const FileDescriptor& fd, const StatT& st, error_code& ec) {
+  if (detail::fchmod(fd.fd, st.st_mode) == -1) {
+    ec = capture_errno();
+    return true;
+  }
+  ec.clear();
+  return false;
+}
+
+bool stat_equivalent(const StatT& st1, const StatT& st2) {
+  return (st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);
+}
+
+file_status FileDescriptor::refresh_status(error_code& ec) {
+  // FD must be open and good.
+  m_status = file_status{};
+  m_stat = {};
+  error_code m_ec;
+  if (detail::fstat(fd, &m_stat) == -1)
+    m_ec = capture_errno();
+  m_status = create_file_status(m_ec, name, m_stat, &ec);
+  return m_status;
+}
+} // namespace
+} // end namespace detail
+
+using detail::capture_errno;
+using detail::ErrorHandler;
+using detail::StatT;
+using detail::TimeSpec;
+using parser::createView;
+using parser::PathParser;
+using parser::string_view_t;
+
+const bool _FilesystemClock::is_steady;
+
+_FilesystemClock::time_point _FilesystemClock::now() noexcept {
+  typedef chrono::duration<rep> __secs;
+#if defined(_LIBCPP_WIN32API)
+  typedef chrono::duration<rep, nano> __nsecs;
+  FILETIME time;
+  GetSystemTimeAsFileTime(&time);
+  TimeSpec tp = detail::filetime_to_timespec(time);
+  return time_point(__secs(tp.tv_sec) +
+                    chrono::duration_cast<duration>(__nsecs(tp.tv_nsec)));
+#elif defined(CLOCK_REALTIME)
+  typedef chrono::duration<rep, nano> __nsecs;
+  struct timespec tp;
+  if (0 != clock_gettime(CLOCK_REALTIME, &tp))
+    __throw_system_error(errno, "clock_gettime(CLOCK_REALTIME) failed");
+  return time_point(__secs(tp.tv_sec) +
+                    chrono::duration_cast<duration>(__nsecs(tp.tv_nsec)));
+#else
+  typedef chrono::duration<rep, micro> __microsecs;
+  timeval tv;
+  gettimeofday(&tv, 0);
+  return time_point(__secs(tv.tv_sec) + __microsecs(tv.tv_usec));
+#endif // CLOCK_REALTIME
+}
+
+filesystem_error::~filesystem_error() {}
+
+void filesystem_error::__create_what(int __num_paths) {
+  const char* derived_what = system_error::what();
+  __storage_->__what_ = [&]() -> string {
+    switch (__num_paths) {
+    case 0:
+      return detail::format_string("filesystem error: %s", derived_what);
+    case 1:
+      return detail::format_string("filesystem error: %s [" PATH_CSTR_FMT "]",
+                                   derived_what, path1().c_str());
+    case 2:
+      return detail::format_string("filesystem error: %s [" PATH_CSTR_FMT "] [" PATH_CSTR_FMT "]",
+                                   derived_what, path1().c_str(), path2().c_str());
+    }
+    _LIBCPP_UNREACHABLE();
+  }();
+}
+
+static path __do_absolute(const path& p, path* cwd, error_code* ec) {
+  if (ec)
+    ec->clear();
+  if (p.is_absolute())
+    return p;
+  *cwd = __current_path(ec);
+  if (ec && *ec)
+    return {};
+  return (*cwd) / p;
+}
+
+path __absolute(const path& p, error_code* ec) {
+  path cwd;
+  return __do_absolute(p, &cwd, ec);
+}
+
+path __canonical(path const& orig_p, error_code* ec) {
+  path cwd;
+  ErrorHandler<path> err("canonical", ec, &orig_p, &cwd);
+
+  path p = __do_absolute(orig_p, &cwd, ec);
+#if (defined(_POSIX_VERSION) && _POSIX_VERSION >= 200112) || defined(_LIBCPP_WIN32API)
+  std::unique_ptr<path::value_type, decltype(&::free)>
+    hold(detail::realpath(p.c_str(), nullptr), &::free);
+  if (hold.get() == nullptr)
+    return err.report(capture_errno());
+  return {hold.get()};
+#else
+  #if defined(__MVS__) && !defined(PATH_MAX)
+    path::value_type buff[ _XOPEN_PATH_MAX + 1 ];
+  #else
+    path::value_type buff[PATH_MAX + 1];
+  #endif
+  path::value_type* ret;
+  if ((ret = detail::realpath(p.c_str(), buff)) == nullptr)
+    return err.report(capture_errno());
+  return {ret};
+#endif
+}
+
+void __copy(const path& from, const path& to, copy_options options,
+            error_code* ec) {
+  ErrorHandler<void> err("copy", ec, &from, &to);
+
+  const bool sym_status = bool(
+      options & (copy_options::create_symlinks | copy_options::skip_symlinks));
+
+  const bool sym_status2 = bool(options & copy_options::copy_symlinks);
+
+  error_code m_ec1;
+  StatT f_st = {};
+  const file_status f = sym_status || sym_status2
+                            ? detail::posix_lstat(from, f_st, &m_ec1)
+                            : detail::posix_stat(from, f_st, &m_ec1);
+  if (m_ec1)
+    return err.report(m_ec1);
+
+  StatT t_st = {};
+  const file_status t = sym_status ? detail::posix_lstat(to, t_st, &m_ec1)
+                                   : detail::posix_stat(to, t_st, &m_ec1);
+
+  if (not status_known(t))
+    return err.report(m_ec1);
+
+  if (!exists(f) || is_other(f) || is_other(t) ||
+      (is_directory(f) && is_regular_file(t)) ||
+      detail::stat_equivalent(f_st, t_st)) {
+    return err.report(errc::function_not_supported);
+  }
+
+  if (ec)
+    ec->clear();
+
+  if (is_symlink(f)) {
+    if (bool(copy_options::skip_symlinks & options)) {
+      // do nothing
+    } else if (not exists(t)) {
+      __copy_symlink(from, to, ec);
+    } else {
+      return err.report(errc::file_exists);
+    }
+    return;
+  } else if (is_regular_file(f)) {
+    if (bool(copy_options::directories_only & options)) {
+      // do nothing
+    } else if (bool(copy_options::create_symlinks & options)) {
+      __create_symlink(from, to, ec);
+    } else if (bool(copy_options::create_hard_links & options)) {
+      __create_hard_link(from, to, ec);
+    } else if (is_directory(t)) {
+      __copy_file(from, to / from.filename(), options, ec);
+    } else {
+      __copy_file(from, to, options, ec);
+    }
+    return;
+  } else if (is_directory(f) && bool(copy_options::create_symlinks & options)) {
+    return err.report(errc::is_a_directory);
+  } else if (is_directory(f) && (bool(copy_options::recursive & options) ||
+                                 copy_options::none == options)) {
+
+    if (!exists(t)) {
+      // create directory to with attributes from 'from'.
+      __create_directory(to, from, ec);
+      if (ec && *ec) {
+        return;
+      }
+    }
+    directory_iterator it =
+        ec ? directory_iterator(from, *ec) : directory_iterator(from);
+    if (ec && *ec) {
+      return;
+    }
+    error_code m_ec2;
+    for (; it != directory_iterator(); it.increment(m_ec2)) {
+      if (m_ec2) {
+        return err.report(m_ec2);
+      }
+      __copy(it->path(), to / it->path().filename(),
+             options | copy_options::__in_recursive_copy, ec);
+      if (ec && *ec) {
+        return;
+      }
+    }
+  }
+}
+
+namespace detail {
+namespace {
+
+#if defined(_LIBCPP_FILESYSTEM_USE_SENDFILE)
+  bool copy_file_impl(FileDescriptor& read_fd, FileDescriptor& write_fd, error_code& ec) {
+    size_t count = read_fd.get_stat().st_size;
+    do {
+      ssize_t res;
+      if ((res = ::sendfile(write_fd.fd, read_fd.fd, nullptr, count)) == -1) {
+        ec = capture_errno();
+        return false;
+      }
+      count -= res;
+    } while (count > 0);
+
+    ec.clear();
+
+    return true;
+  }
+#elif defined(_LIBCPP_FILESYSTEM_USE_COPYFILE)
+  bool copy_file_impl(FileDescriptor& read_fd, FileDescriptor& write_fd, error_code& ec) {
+    struct CopyFileState {
+      copyfile_state_t state;
+      CopyFileState() { state = copyfile_state_alloc(); }
+      ~CopyFileState() { copyfile_state_free(state); }
+
+    private:
+      CopyFileState(CopyFileState const&) = delete;
+      CopyFileState& operator=(CopyFileState const&) = delete;
+    };
+
+    CopyFileState cfs;
+    if (fcopyfile(read_fd.fd, write_fd.fd, cfs.state, COPYFILE_DATA) < 0) {
+      ec = capture_errno();
+      return false;
+    }
+
+    ec.clear();
+    return true;
+  }
+#elif defined(_LIBCPP_FILESYSTEM_USE_FSTREAM)
+  bool copy_file_impl(FileDescriptor& read_fd, FileDescriptor& write_fd, error_code& ec) {
+    ifstream in;
+    in.__open(read_fd.fd, ios::binary);
+    if (!in.is_open()) {
+      // This assumes that __open didn't reset the error code.
+      ec = capture_errno();
+      return false;
+    }
+    read_fd.fd = -1;
+    ofstream out;
+    out.__open(write_fd.fd, ios::binary);
+    if (!out.is_open()) {
+      ec = capture_errno();
+      return false;
+    }
+    write_fd.fd = -1;
+
+    if (in.good() && out.good()) {
+      using InIt = istreambuf_iterator<char>;
+      using OutIt = ostreambuf_iterator<char>;
+      InIt bin(in);
+      InIt ein;
+      OutIt bout(out);
+      copy(bin, ein, bout);
+    }
+    if (out.fail() || in.fail()) {
+      ec = make_error_code(errc::io_error);
+      return false;
+    }
+
+    ec.clear();
+    return true;
+  }
+#else
+# error "Unknown implementation for copy_file_impl"
+#endif // copy_file_impl implementation
+
+} // end anonymous namespace
+} // end namespace detail
+
+bool __copy_file(const path& from, const path& to, copy_options options,
+                 error_code* ec) {
+  using detail::FileDescriptor;
+  ErrorHandler<bool> err("copy_file", ec, &to, &from);
+
+  error_code m_ec;
+  FileDescriptor from_fd = FileDescriptor::create_with_status(
+      &from, m_ec, O_RDONLY | O_NONBLOCK | O_BINARY);
+  if (m_ec)
+    return err.report(m_ec);
+
+  auto from_st = from_fd.get_status();
+  StatT const& from_stat = from_fd.get_stat();
+  if (!is_regular_file(from_st)) {
+    if (not m_ec)
+      m_ec = make_error_code(errc::not_supported);
+    return err.report(m_ec);
+  }
+
+  const bool skip_existing = bool(copy_options::skip_existing & options);
+  const bool update_existing = bool(copy_options::update_existing & options);
+  const bool overwrite_existing =
+      bool(copy_options::overwrite_existing & options);
+
+  StatT to_stat_path;
+  file_status to_st = detail::posix_stat(to, to_stat_path, &m_ec);
+  if (!status_known(to_st))
+    return err.report(m_ec);
+
+  const bool to_exists = exists(to_st);
+  if (to_exists && !is_regular_file(to_st))
+    return err.report(errc::not_supported);
+
+  if (to_exists && detail::stat_equivalent(from_stat, to_stat_path))
+    return err.report(errc::file_exists);
+
+  if (to_exists && skip_existing)
+    return false;
+
+  bool ShouldCopy = [&]() {
+    if (to_exists && update_existing) {
+      auto from_time = detail::extract_mtime(from_stat);
+      auto to_time = detail::extract_mtime(to_stat_path);
+      if (from_time.tv_sec < to_time.tv_sec)
+        return false;
+      if (from_time.tv_sec == to_time.tv_sec &&
+          from_time.tv_nsec <= to_time.tv_nsec)
+        return false;
+      return true;
+    }
+    if (!to_exists || overwrite_existing)
+      return true;
+    return err.report(errc::file_exists);
+  }();
+  if (!ShouldCopy)
+    return false;
+
+  // Don't truncate right away. We may not be opening the file we originally
+  // looked at; we'll check this later.
+  int to_open_flags = O_WRONLY | O_BINARY;
+  if (!to_exists)
+    to_open_flags |= O_CREAT;
+  FileDescriptor to_fd = FileDescriptor::create_with_status(
+      &to, m_ec, to_open_flags, from_stat.st_mode);
+  if (m_ec)
+    return err.report(m_ec);
+
+  if (to_exists) {
+    // Check that the file we initially stat'ed is equivalent to the one
+    // we opened.
+    // FIXME: report this better.
+    if (!detail::stat_equivalent(to_stat_path, to_fd.get_stat()))
+      return err.report(errc::bad_file_descriptor);
+
+    // Set the permissions and truncate the file we opened.
+    if (detail::posix_fchmod(to_fd, from_stat, m_ec))
+      return err.report(m_ec);
+    if (detail::posix_ftruncate(to_fd, 0, m_ec))
+      return err.report(m_ec);
+  }
+
+  if (!copy_file_impl(from_fd, to_fd, m_ec)) {
+    // FIXME: Remove the dest file if we failed, and it didn't exist previously.
+    return err.report(m_ec);
+  }
+
+  return true;
+}
+
+void __copy_symlink(const path& existing_symlink, const path& new_symlink,
+                    error_code* ec) {
+  const path real_path(__read_symlink(existing_symlink, ec));
+  if (ec && *ec) {
+    return;
+  }
+#if defined(_LIBCPP_WIN32API)
+  error_code local_ec;
+  if (is_directory(real_path, local_ec))
+    __create_directory_symlink(real_path, new_symlink, ec);
+  else
+#endif
+  __create_symlink(real_path, new_symlink, ec);
+}
+
+bool __create_directories(const path& p, error_code* ec) {
+  ErrorHandler<bool> err("create_directories", ec, &p);
+
+  error_code m_ec;
+  auto const st = detail::posix_stat(p, &m_ec);
+  if (!status_known(st))
+    return err.report(m_ec);
+  else if (is_directory(st))
+    return false;
+  else if (exists(st))
+    return err.report(errc::file_exists);
+
+  const path parent = p.parent_path();
+  if (!parent.empty()) {
+    const file_status parent_st = status(parent, m_ec);
+    if (not status_known(parent_st))
+      return err.report(m_ec);
+    if (not exists(parent_st)) {
+      if (parent == p)
+        return err.report(errc::invalid_argument);
+      __create_directories(parent, ec);
+      if (ec && *ec) {
+        return false;
+      }
+    } else if (not is_directory(parent_st))
+      return err.report(errc::not_a_directory);
+  }
+  bool ret = __create_directory(p, &m_ec);
+  if (m_ec)
+    return err.report(m_ec);
+  return ret;
+}
+
+bool __create_directory(const path& p, error_code* ec) {
+  ErrorHandler<bool> err("create_directory", ec, &p);
+
+  if (detail::mkdir(p.c_str(), static_cast<int>(perms::all)) == 0)
+    return true;
+
+  if (errno != EEXIST)
+    return err.report(capture_errno());
+  error_code mec = capture_errno();
+  error_code ignored_ec;
+  const file_status st = status(p, ignored_ec);
+  if (!is_directory(st))
+    return err.report(mec);
+  return false;
+}
+
+bool __create_directory(path const& p, path const& attributes, error_code* ec) {
+  ErrorHandler<bool> err("create_directory", ec, &p, &attributes);
+
+  StatT attr_stat;
+  error_code mec;
+  file_status st = detail::posix_stat(attributes, attr_stat, &mec);
+  if (!status_known(st))
+    return err.report(mec);
+  if (!is_directory(st))
+    return err.report(errc::not_a_directory,
+                      "the specified attribute path is invalid");
+
+  if (detail::mkdir(p.c_str(), attr_stat.st_mode) == 0)
+    return true;
+
+  if (errno != EEXIST)
+    return err.report(capture_errno());
+
+  mec = capture_errno();
+    error_code ignored_ec;
+  st = status(p, ignored_ec);
+  if (!is_directory(st))
+    return err.report(mec);
+  return false;
+}
+
+void __create_directory_symlink(path const& from, path const& to,
+                                error_code* ec) {
+  ErrorHandler<void> err("create_directory_symlink", ec, &from, &to);
+  if (detail::symlink_dir(from.c_str(), to.c_str()) == -1)
+    return err.report(capture_errno());
+}
+
+void __create_hard_link(const path& from, const path& to, error_code* ec) {
+  ErrorHandler<void> err("create_hard_link", ec, &from, &to);
+  if (detail::link(from.c_str(), to.c_str()) == -1)
+    return err.report(capture_errno());
+}
+
+void __create_symlink(path const& from, path const& to, error_code* ec) {
+  ErrorHandler<void> err("create_symlink", ec, &from, &to);
+  if (detail::symlink_file(from.c_str(), to.c_str()) == -1)
+    return err.report(capture_errno());
+}
+
+path __current_path(error_code* ec) {
+  ErrorHandler<path> err("current_path", ec);
+
+#if defined(_LIBCPP_WIN32API) || defined(__GLIBC__) || defined(__APPLE__)
+  // Common extension outside of POSIX getcwd() spec, without needing to
+  // preallocate a buffer. Also supported by a number of other POSIX libcs.
+  int size = 0;
+  path::value_type* ptr = nullptr;
+  typedef decltype(&::free) Deleter;
+  Deleter deleter = &::free;
+#else
+  auto size = ::pathconf(".", _PC_PATH_MAX);
+  _LIBCPP_ASSERT(size >= 0, "pathconf returned a 0 as max size");
+
+  auto buff = unique_ptr<path::value_type[]>(new path::value_type[size + 1]);
+  path::value_type* ptr = buff.get();
+
+  // Preallocated buffer, don't free the buffer in the second unique_ptr
+  // below.
+  struct Deleter { void operator()(void*) const {} };
+  Deleter deleter;
+#endif
+
+  unique_ptr<path::value_type, Deleter> hold(detail::getcwd(ptr, size),
+                                             deleter);
+  if (hold.get() == nullptr)
+    return err.report(capture_errno(), "call to getcwd failed");
+
+  return {hold.get()};
+}
+
+void __current_path(const path& p, error_code* ec) {
+  ErrorHandler<void> err("current_path", ec, &p);
+  if (detail::chdir(p.c_str()) == -1)
+    err.report(capture_errno());
+}
+
+bool __equivalent(const path& p1, const path& p2, error_code* ec) {
+  ErrorHandler<bool> err("equivalent", ec, &p1, &p2);
+
+  error_code ec1, ec2;
+  StatT st1 = {}, st2 = {};
+  auto s1 = detail::posix_stat(p1.native(), st1, &ec1);
+  if (!exists(s1))
+    return err.report(errc::not_supported);
+  auto s2 = detail::posix_stat(p2.native(), st2, &ec2);
+  if (!exists(s2))
+    return err.report(errc::not_supported);
+
+  return detail::stat_equivalent(st1, st2);
+}
+
+uintmax_t __file_size(const path& p, error_code* ec) {
+  ErrorHandler<uintmax_t> err("file_size", ec, &p);
+
+  error_code m_ec;
+  StatT st;
+  file_status fst = detail::posix_stat(p, st, &m_ec);
+  if (!exists(fst) || !is_regular_file(fst)) {
+    errc error_kind =
+        is_directory(fst) ? errc::is_a_directory : errc::not_supported;
+    if (!m_ec)
+      m_ec = make_error_code(error_kind);
+    return err.report(m_ec);
+  }
+  // is_regular_file(p) == true
+  return static_cast<uintmax_t>(st.st_size);
+}
+
+uintmax_t __hard_link_count(const path& p, error_code* ec) {
+  ErrorHandler<uintmax_t> err("hard_link_count", ec, &p);
+
+  error_code m_ec;
+  StatT st;
+  detail::posix_stat(p, st, &m_ec);
+  if (m_ec)
+    return err.report(m_ec);
+  return static_cast<uintmax_t>(st.st_nlink);
+}
+
+bool __fs_is_empty(const path& p, error_code* ec) {
+  ErrorHandler<bool> err("is_empty", ec, &p);
+
+  error_code m_ec;
+  StatT pst;
+  auto st = detail::posix_stat(p, pst, &m_ec);
+  if (m_ec)
+    return err.report(m_ec);
+  else if (!is_directory(st) && !is_regular_file(st))
+    return err.report(errc::not_supported);
+  else if (is_directory(st)) {
+    auto it = ec ? directory_iterator(p, *ec) : directory_iterator(p);
+    if (ec && *ec)
+      return false;
+    return it == directory_iterator{};
+  } else if (is_regular_file(st))
+    return static_cast<uintmax_t>(pst.st_size) == 0;
+
+  _LIBCPP_UNREACHABLE();
+}
+
+static file_time_type __extract_last_write_time(const path& p, const StatT& st,
+                                                error_code* ec) {
+  using detail::fs_time;
+  ErrorHandler<file_time_type> err("last_write_time", ec, &p);
+
+  auto ts = detail::extract_mtime(st);
+  if (!fs_time::is_representable(ts))
+    return err.report(errc::value_too_large);
+
+  return fs_time::convert_from_timespec(ts);
+}
+
+file_time_type __last_write_time(const path& p, error_code* ec) {
+  using namespace chrono;
+  ErrorHandler<file_time_type> err("last_write_time", ec, &p);
+
+  error_code m_ec;
+  StatT st;
+  detail::posix_stat(p, st, &m_ec);
+  if (m_ec)
+    return err.report(m_ec);
+  return __extract_last_write_time(p, st, ec);
+}
+
+void __last_write_time(const path& p, file_time_type new_time, error_code* ec) {
+  using detail::fs_time;
+  ErrorHandler<void> err("last_write_time", ec, &p);
+
+#if defined(_LIBCPP_WIN32API)
+  TimeSpec ts;
+  if (!fs_time::convert_to_timespec(ts, new_time))
+    return err.report(errc::value_too_large);
+  detail::WinHandle h(p.c_str(), FILE_WRITE_ATTRIBUTES, 0);
+  if (!h)
+    return err.report(detail::make_windows_error(GetLastError()));
+  FILETIME last_write = timespec_to_filetime(ts);
+  if (!SetFileTime(h, nullptr, nullptr, &last_write))
+    return err.report(detail::make_windows_error(GetLastError()));
+#else
+  error_code m_ec;
+  array<TimeSpec, 2> tbuf;
+#if !defined(_LIBCPP_USE_UTIMENSAT)
+  // This implementation has a race condition between determining the
+  // last access time and attempting to set it to the same value using
+  // ::utimes
+  StatT st;
+  file_status fst = detail::posix_stat(p, st, &m_ec);
+  if (m_ec)
+    return err.report(m_ec);
+  tbuf[0] = detail::extract_atime(st);
+#else
+  tbuf[0].tv_sec = 0;
+  tbuf[0].tv_nsec = UTIME_OMIT;
+#endif
+  if (!fs_time::convert_to_timespec(tbuf[1], new_time))
+    return err.report(errc::value_too_large);
+
+  detail::set_file_times(p, tbuf, m_ec);
+  if (m_ec)
+    return err.report(m_ec);
+#endif
+}
+
+void __permissions(const path& p, perms prms, perm_options opts,
+                   error_code* ec) {
+  ErrorHandler<void> err("permissions", ec, &p);
+
+  auto has_opt = [&](perm_options o) { return bool(o & opts); };
+  const bool resolve_symlinks = !has_opt(perm_options::nofollow);
+  const bool add_perms = has_opt(perm_options::add);
+  const bool remove_perms = has_opt(perm_options::remove);
+  _LIBCPP_ASSERT(
+      (add_perms + remove_perms + has_opt(perm_options::replace)) == 1,
+      "One and only one of the perm_options constants replace, add, or remove "
+      "is present in opts");
+
+  bool set_sym_perms = false;
+  prms &= perms::mask;
+  if (!resolve_symlinks || (add_perms || remove_perms)) {
+    error_code m_ec;
+    file_status st = resolve_symlinks ? detail::posix_stat(p, &m_ec)
+                                      : detail::posix_lstat(p, &m_ec);
+    set_sym_perms = is_symlink(st);
+    if (m_ec)
+      return err.report(m_ec);
+    _LIBCPP_ASSERT(st.permissions() != perms::unknown,
+                   "Permissions unexpectedly unknown");
+    if (add_perms)
+      prms |= st.permissions();
+    else if (remove_perms)
+      prms = st.permissions() & ~prms;
+  }
+  const auto real_perms = static_cast<detail::ModeT>(prms & perms::mask);
+
+#if defined(AT_SYMLINK_NOFOLLOW) && defined(AT_FDCWD)
+  const int flags = set_sym_perms ? AT_SYMLINK_NOFOLLOW : 0;
+  if (detail::fchmodat(AT_FDCWD, p.c_str(), real_perms, flags) == -1) {
+    return err.report(capture_errno());
+  }
+#else
+  if (set_sym_perms)
+    return err.report(errc::operation_not_supported);
+  if (::chmod(p.c_str(), real_perms) == -1) {
+    return err.report(capture_errno());
+  }
+#endif
+}
+
+path __read_symlink(const path& p, error_code* ec) {
+  ErrorHandler<path> err("read_symlink", ec, &p);
+
+#if defined(PATH_MAX) || defined(MAX_SYMLINK_SIZE)
+  struct NullDeleter { void operator()(void*) const {} };
+#ifdef MAX_SYMLINK_SIZE
+  const size_t size = MAX_SYMLINK_SIZE + 1;
+#else
+  const size_t size = PATH_MAX + 1;
+#endif
+  path::value_type stack_buff[size];
+  auto buff = std::unique_ptr<path::value_type[], NullDeleter>(stack_buff);
+#else
+  StatT sb;
+  if (detail::lstat(p.c_str(), &sb) == -1) {
+    return err.report(capture_errno());
+  }
+  const size_t size = sb.st_size + 1;
+  auto buff = unique_ptr<path::value_type[]>(new path::value_type[size]);
+#endif
+  detail::SSizeT ret;
+  if ((ret = detail::readlink(p.c_str(), buff.get(), size)) == -1)
+    return err.report(capture_errno());
+  _LIBCPP_ASSERT(ret > 0, "TODO");
+  if (static_cast<size_t>(ret) >= size)
+    return err.report(errc::value_too_large);
+  buff[ret] = 0;
+  return {buff.get()};
+}
+
+bool __remove(const path& p, error_code* ec) {
+  ErrorHandler<bool> err("remove", ec, &p);
+  if (detail::remove(p.c_str()) == -1) {
+    if (errno != ENOENT)
+      err.report(capture_errno());
+    return false;
+  }
+  return true;
+}
+
+namespace {
+
+uintmax_t remove_all_impl(path const& p, error_code& ec) {
+  const auto npos = static_cast<uintmax_t>(-1);
+  const file_status st = __symlink_status(p, &ec);
+  if (ec)
+    return npos;
+  uintmax_t count = 1;
+  if (is_directory(st)) {
+    for (directory_iterator it(p, ec); !ec && it != directory_iterator();
+         it.increment(ec)) {
+      auto other_count = remove_all_impl(it->path(), ec);
+      if (ec)
+        return npos;
+      count += other_count;
+    }
+    if (ec)
+      return npos;
+  }
+  if (!__remove(p, &ec))
+    return npos;
+  return count;
+}
+
+} // end namespace
+
+uintmax_t __remove_all(const path& p, error_code* ec) {
+  ErrorHandler<uintmax_t> err("remove_all", ec, &p);
+
+  error_code mec;
+  auto count = remove_all_impl(p, mec);
+  if (mec) {
+    if (mec == errc::no_such_file_or_directory)
+      return 0;
+    return err.report(mec);
+  }
+  return count;
+}
+
+void __rename(const path& from, const path& to, error_code* ec) {
+  ErrorHandler<void> err("rename", ec, &from, &to);
+  if (detail::rename(from.c_str(), to.c_str()) == -1)
+    err.report(capture_errno());
+}
+
+void __resize_file(const path& p, uintmax_t size, error_code* ec) {
+  ErrorHandler<void> err("resize_file", ec, &p);
+  if (detail::truncate(p.c_str(), static_cast< ::off_t>(size)) == -1)
+    return err.report(capture_errno());
+}
+
+space_info __space(const path& p, error_code* ec) {
+  ErrorHandler<void> err("space", ec, &p);
+  space_info si;
+  detail::StatVFS m_svfs = {};
+  if (detail::statvfs(p.c_str(), &m_svfs) == -1) {
+    err.report(capture_errno());
+    si.capacity = si.free = si.available = static_cast<uintmax_t>(-1);
+    return si;
+  }
+  // Multiply with overflow checking.
+  auto do_mult = [&](uintmax_t& out, uintmax_t other) {
+    out = other * m_svfs.f_frsize;
+    if (other == 0 || out / other != m_svfs.f_frsize)
+      out = static_cast<uintmax_t>(-1);
+  };
+  do_mult(si.capacity, m_svfs.f_blocks);
+  do_mult(si.free, m_svfs.f_bfree);
+  do_mult(si.available, m_svfs.f_bavail);
+  return si;
+}
+
+file_status __status(const path& p, error_code* ec) {
+  return detail::posix_stat(p, ec);
+}
+
+file_status __symlink_status(const path& p, error_code* ec) {
+  return detail::posix_lstat(p, ec);
+}
+
+path __temp_directory_path(error_code* ec) {
+  ErrorHandler<path> err("temp_directory_path", ec);
+
+#if defined(_LIBCPP_WIN32API)
+  wchar_t buf[MAX_PATH];
+  DWORD retval = GetTempPathW(MAX_PATH, buf);
+  if (!retval)
+    return err.report(detail::make_windows_error(GetLastError()));
+  if (retval > MAX_PATH)
+    return err.report(errc::filename_too_long);
+  // GetTempPathW returns a path with a trailing slash, which we
+  // shouldn't include for consistency.
+  if (buf[retval-1] == L'\\')
+    buf[retval-1] = L'\0';
+  path p(buf);
+#else
+  const char* env_paths[] = {"TMPDIR", "TMP", "TEMP", "TEMPDIR"};
+  const char* ret = nullptr;
+
+  for (auto& ep : env_paths)
+    if ((ret = getenv(ep)))
+      break;
+  if (ret == nullptr)
+    ret = "/tmp";
+
+  path p(ret);
+#endif
+  error_code m_ec;
+  file_status st = detail::posix_stat(p, &m_ec);
+  if (!status_known(st))
+    return err.report(m_ec, "cannot access path " PATH_CSTR_FMT, p.c_str());
+
+  if (!exists(st) || !is_directory(st))
+    return err.report(errc::not_a_directory,
+                      "path " PATH_CSTR_FMT " is not a directory", p.c_str());
+
+  return p;
+}
+
+path __weakly_canonical(const path& p, error_code* ec) {
+  ErrorHandler<path> err("weakly_canonical", ec, &p);
+
+  if (p.empty())
+    return __canonical("", ec);
+
+  path result;
+  path tmp;
+  tmp.__reserve(p.native().size());
+  auto PP = PathParser::CreateEnd(p.native());
+  --PP;
+  vector<string_view_t> DNEParts;
+
+  while (PP.State != PathParser::PS_BeforeBegin) {
+    tmp.assign(createView(p.native().data(), &PP.RawEntry.back()));
+    error_code m_ec;
+    file_status st = __status(tmp, &m_ec);
+    if (!status_known(st)) {
+      return err.report(m_ec);
+    } else if (exists(st)) {
+      result = __canonical(tmp, ec);
+      break;
+    }
+    DNEParts.push_back(*PP);
+    --PP;
+  }
+  if (PP.State == PathParser::PS_BeforeBegin)
+    result = __canonical("", ec);
+  if (ec)
+    ec->clear();
+  if (DNEParts.empty())
+    return result;
+  for (auto It = DNEParts.rbegin(); It != DNEParts.rend(); ++It)
+    result /= *It;
+  return result.lexically_normal();
+}
+
+///////////////////////////////////////////////////////////////////////////////
+//                            path definitions
+///////////////////////////////////////////////////////////////////////////////
+
+constexpr path::value_type path::preferred_separator;
+
+path& path::replace_extension(path const& replacement) {
+  path p = extension();
+  if (not p.empty()) {
+    __pn_.erase(__pn_.size() - p.native().size());
+  }
+  if (!replacement.empty()) {
+    if (replacement.native()[0] != '.') {
+      __pn_ += PS(".");
+    }
+    __pn_.append(replacement.__pn_);
+  }
+  return *this;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// path.decompose
+
+string_view_t path::__root_name() const {
+  auto PP = PathParser::CreateBegin(__pn_);
+  if (PP.State == PathParser::PS_InRootName)
+    return *PP;
+  return {};
+}
+
+string_view_t path::__root_directory() const {
+  auto PP = PathParser::CreateBegin(__pn_);
+  if (PP.State == PathParser::PS_InRootName)
+    ++PP;
+  if (PP.State == PathParser::PS_InRootDir)
+    return *PP;
+  return {};
+}
+
+string_view_t path::__root_path_raw() const {
+  auto PP = PathParser::CreateBegin(__pn_);
+  if (PP.State == PathParser::PS_InRootName) {
+    auto NextCh = PP.peek();
+    if (NextCh && isSeparator(*NextCh)) {
+      ++PP;
+      return createView(__pn_.data(), &PP.RawEntry.back());
+    }
+    return PP.RawEntry;
+  }
+  if (PP.State == PathParser::PS_InRootDir)
+    return *PP;
+  return {};
+}
+
+static bool ConsumeRootName(PathParser *PP) {
+  static_assert(PathParser::PS_BeforeBegin == 1 &&
+      PathParser::PS_InRootName == 2,
+      "Values for enums are incorrect");
+  while (PP->State <= PathParser::PS_InRootName)
+    ++(*PP);
+  return PP->State == PathParser::PS_AtEnd;
+}
+
+static bool ConsumeRootDir(PathParser* PP) {
+  static_assert(PathParser::PS_BeforeBegin == 1 &&
+                PathParser::PS_InRootName == 2 &&
+                PathParser::PS_InRootDir == 3, "Values for enums are incorrect");
+  while (PP->State <= PathParser::PS_InRootDir)
+    ++(*PP);
+  return PP->State == PathParser::PS_AtEnd;
+}
+
+string_view_t path::__relative_path() const {
+  auto PP = PathParser::CreateBegin(__pn_);
+  if (ConsumeRootDir(&PP))
+    return {};
+  return createView(PP.RawEntry.data(), &__pn_.back());
+}
+
+string_view_t path::__parent_path() const {
+  if (empty())
+    return {};
+  // Determine if we have a root path but not a relative path. In that case
+  // return *this.
+  {
+    auto PP = PathParser::CreateBegin(__pn_);
+    if (ConsumeRootDir(&PP))
+      return __pn_;
+  }
+  // Otherwise remove a single element from the end of the path, and return
+  // a string representing that path
+  {
+    auto PP = PathParser::CreateEnd(__pn_);
+    --PP;
+    if (PP.RawEntry.data() == __pn_.data())
+      return {};
+    --PP;
+    return createView(__pn_.data(), &PP.RawEntry.back());
+  }
+}
+
+string_view_t path::__filename() const {
+  if (empty())
+    return {};
+  {
+    PathParser PP = PathParser::CreateBegin(__pn_);
+    if (ConsumeRootDir(&PP))
+      return {};
+  }
+  return *(--PathParser::CreateEnd(__pn_));
+}
+
+string_view_t path::__stem() const {
+  return parser::separate_filename(__filename()).first;
+}
+
+string_view_t path::__extension() const {
+  return parser::separate_filename(__filename()).second;
+}
+
+////////////////////////////////////////////////////////////////////////////
+// path.gen
+
+enum PathPartKind : unsigned char {
+  PK_None,
+  PK_RootSep,
+  PK_Filename,
+  PK_Dot,
+  PK_DotDot,
+  PK_TrailingSep
+};
+
+static PathPartKind ClassifyPathPart(string_view_t Part) {
+  if (Part.empty())
+    return PK_TrailingSep;
+  if (Part == PS("."))
+    return PK_Dot;
+  if (Part == PS(".."))
+    return PK_DotDot;
+  if (Part == PS("/"))
+    return PK_RootSep;
+#if defined(_LIBCPP_WIN32API)
+  if (Part == PS("\\"))
+    return PK_RootSep;
+#endif
+  return PK_Filename;
+}
+
+path path::lexically_normal() const {
+  if (__pn_.empty())
+    return *this;
+
+  using PartKindPair = pair<string_view_t, PathPartKind>;
+  vector<PartKindPair> Parts;
+  // Guess as to how many elements the path has to avoid reallocating.
+  Parts.reserve(32);
+
+  // Track the total size of the parts as we collect them. This allows the
+  // resulting path to reserve the correct amount of memory.
+  size_t NewPathSize = 0;
+  auto AddPart = [&](PathPartKind K, string_view_t P) {
+    NewPathSize += P.size();
+    Parts.emplace_back(P, K);
+  };
+  auto LastPartKind = [&]() {
+    if (Parts.empty())
+      return PK_None;
+    return Parts.back().second;
+  };
+
+  bool MaybeNeedTrailingSep = false;
+  // Build a stack containing the remaining elements of the path, popping off
+  // elements which occur before a '..' entry.
+  for (auto PP = PathParser::CreateBegin(__pn_); PP; ++PP) {
+    auto Part = *PP;
+    PathPartKind Kind = ClassifyPathPart(Part);
+    switch (Kind) {
+    case PK_Filename:
+    case PK_RootSep: {
+      // Add all non-dot and non-dot-dot elements to the stack of elements.
+      AddPart(Kind, Part);
+      MaybeNeedTrailingSep = false;
+      break;
+    }
+    case PK_DotDot: {
+      // Only push a ".." element if there are no elements preceding the "..",
+      // or if the preceding element is itself "..".
+      auto LastKind = LastPartKind();
+      if (LastKind == PK_Filename) {
+        NewPathSize -= Parts.back().first.size();
+        Parts.pop_back();
+      } else if (LastKind != PK_RootSep)
+        AddPart(PK_DotDot, PS(".."));
+      MaybeNeedTrailingSep = LastKind == PK_Filename;
+      break;
+    }
+    case PK_Dot:
+    case PK_TrailingSep: {
+      MaybeNeedTrailingSep = true;
+      break;
+    }
+    case PK_None:
+      _LIBCPP_UNREACHABLE();
+    }
+  }
+  // [fs.path.generic]p6.8: If the path is empty, add a dot.
+  if (Parts.empty())
+    return PS(".");
+
+  // [fs.path.generic]p6.7: If the last filename is dot-dot, remove any
+  // trailing directory-separator.
+  bool NeedTrailingSep = MaybeNeedTrailingSep && LastPartKind() == PK_Filename;
+
+  path Result;
+  Result.__pn_.reserve(Parts.size() + NewPathSize + NeedTrailingSep);
+  for (auto& PK : Parts)
+    Result /= PK.first;
+
+  if (NeedTrailingSep)
+    Result /= PS("");
+
+  Result.make_preferred();
+  return Result;
+}
+
+static int DetermineLexicalElementCount(PathParser PP) {
+  int Count = 0;
+  for (; PP; ++PP) {
+    auto Elem = *PP;
+    if (Elem == PS(".."))
+      --Count;
+    else if (Elem != PS(".") && Elem != PS(""))
+      ++Count;
+  }
+  return Count;
+}
+
+path path::lexically_relative(const path& base) const {
+  { // perform root-name/root-directory mismatch checks
+    auto PP = PathParser::CreateBegin(__pn_);
+    auto PPBase = PathParser::CreateBegin(base.__pn_);
+    auto CheckIterMismatchAtBase = [&]() {
+      return PP.State != PPBase.State &&
+             (PP.inRootPath() || PPBase.inRootPath());
+    };
+    if (PP.inRootName() && PPBase.inRootName()) {
+      if (*PP != *PPBase)
+        return {};
+    } else if (CheckIterMismatchAtBase())
+      return {};
+
+    if (PP.inRootPath())
+      ++PP;
+    if (PPBase.inRootPath())
+      ++PPBase;
+    if (CheckIterMismatchAtBase())
+      return {};
+  }
+
+  // Find the first mismatching element
+  auto PP = PathParser::CreateBegin(__pn_);
+  auto PPBase = PathParser::CreateBegin(base.__pn_);
+  while (PP && PPBase && PP.State == PPBase.State && *PP == *PPBase) {
+    ++PP;
+    ++PPBase;
+  }
+
+  // If there is no mismatch, return ".".
+  if (!PP && !PPBase)
+    return ".";
+
+  // Otherwise, determine the number of elements, 'n', which are not dot or
+  // dot-dot minus the number of dot-dot elements.
+  int ElemCount = DetermineLexicalElementCount(PPBase);
+  if (ElemCount < 0)
+    return {};
+
+  // if n == 0 and (a == end() || a->empty()), returns path("."); otherwise
+  if (ElemCount == 0 && (PP.atEnd() || *PP == PS("")))
+    return PS(".");
+
+  // return a path constructed with 'n' dot-dot elements, followed by the the
+  // elements of '*this' after the mismatch.
+  path Result;
+  // FIXME: Reserve enough room in Result that it won't have to re-allocate.
+  while (ElemCount--)
+    Result /= PS("..");
+  for (; PP; ++PP)
+    Result /= *PP;
+  return Result;
+}
+
+////////////////////////////////////////////////////////////////////////////
+// path.comparisons
+static int CompareRootName(PathParser *LHS, PathParser *RHS) {
+  if (!LHS->inRootName() && !RHS->inRootName())
+    return 0;
+
+  auto GetRootName = [](PathParser *Parser) -> string_view_t {
+    return Parser->inRootName() ? **Parser : PS("");
+  };
+  int res = GetRootName(LHS).compare(GetRootName(RHS));
+  ConsumeRootName(LHS);
+  ConsumeRootName(RHS);
+  return res;
+}
+
+static int CompareRootDir(PathParser *LHS, PathParser *RHS) {
+  if (!LHS->inRootDir() && RHS->inRootDir())
+    return -1;
+  else if (LHS->inRootDir() && !RHS->inRootDir())
+    return 1;
+  else {
+    ConsumeRootDir(LHS);
+    ConsumeRootDir(RHS);
+    return 0;
+  }
+}
+
+static int CompareRelative(PathParser *LHSPtr, PathParser *RHSPtr) {
+  auto &LHS = *LHSPtr;
+  auto &RHS = *RHSPtr;
+
+  int res;
+  while (LHS && RHS) {
+    if ((res = (*LHS).compare(*RHS)) != 0)
+      return res;
+    ++LHS;
+    ++RHS;
+  }
+  return 0;
+}
+
+static int CompareEndState(PathParser *LHS, PathParser *RHS) {
+  if (LHS->atEnd() && !RHS->atEnd())
+    return -1;
+  else if (!LHS->atEnd() && RHS->atEnd())
+    return 1;
+  return 0;
+}
+
+int path::__compare(string_view_t __s) const {
+  auto LHS = PathParser::CreateBegin(__pn_);
+  auto RHS = PathParser::CreateBegin(__s);
+  int res;
+
+  if ((res = CompareRootName(&LHS, &RHS)) != 0)
+    return res;
+
+  if ((res = CompareRootDir(&LHS, &RHS)) != 0)
+    return res;
+
+  if ((res = CompareRelative(&LHS, &RHS)) != 0)
+    return res;
+
+  return CompareEndState(&LHS, &RHS);
+}
+
+////////////////////////////////////////////////////////////////////////////
+// path.nonmembers
+size_t hash_value(const path& __p) noexcept {
+  auto PP = PathParser::CreateBegin(__p.native());
+  size_t hash_value = 0;
+  hash<string_view_t> hasher;
+  while (PP) {
+    hash_value = __hash_combine(hash_value, hasher(*PP));
+    ++PP;
+  }
+  return hash_value;
+}
+
+////////////////////////////////////////////////////////////////////////////
+// path.itr
+path::iterator path::begin() const {
+  auto PP = PathParser::CreateBegin(__pn_);
+  iterator it;
+  it.__path_ptr_ = this;
+  it.__state_ = static_cast<path::iterator::_ParserState>(PP.State);
+  it.__entry_ = PP.RawEntry;
+  it.__stashed_elem_.__assign_view(*PP);
+  return it;
+}
+
+path::iterator path::end() const {
+  iterator it{};
+  it.__state_ = path::iterator::_AtEnd;
+  it.__path_ptr_ = this;
+  return it;
+}
+
+path::iterator& path::iterator::__increment() {
+  PathParser PP(__path_ptr_->native(), __entry_, __state_);
+  ++PP;
+  __state_ = static_cast<_ParserState>(PP.State);
+  __entry_ = PP.RawEntry;
+  __stashed_elem_.__assign_view(*PP);
+  return *this;
+}
+
+path::iterator& path::iterator::__decrement() {
+  PathParser PP(__path_ptr_->native(), __entry_, __state_);
+  --PP;
+  __state_ = static_cast<_ParserState>(PP.State);
+  __entry_ = PP.RawEntry;
+  __stashed_elem_.__assign_view(*PP);
+  return *this;
+}
+
+#if defined(_LIBCPP_WIN32API)
+////////////////////////////////////////////////////////////////////////////
+// Windows path conversions
+size_t __wide_to_char(const wstring &str, char *out, size_t outlen) {
+  if (str.empty())
+    return 0;
+  ErrorHandler<size_t> err("__wide_to_char", nullptr);
+  UINT codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
+  BOOL used_default = FALSE;
+  int ret = WideCharToMultiByte(codepage, 0, str.data(), str.size(), out,
+                                outlen, nullptr, &used_default);
+  if (ret <= 0 || used_default)
+    return err.report(errc::illegal_byte_sequence);
+  return ret;
+}
+
+size_t __char_to_wide(const string &str, wchar_t *out, size_t outlen) {
+  if (str.empty())
+    return 0;
+  ErrorHandler<size_t> err("__char_to_wide", nullptr);
+  UINT codepage = AreFileApisANSI() ? CP_ACP : CP_OEMCP;
+  int ret = MultiByteToWideChar(codepage, MB_ERR_INVALID_CHARS, str.data(),
+                                str.size(), out, outlen);
+  if (ret <= 0)
+    return err.report(errc::illegal_byte_sequence);
+  return ret;
+}
+#endif
+
+
+///////////////////////////////////////////////////////////////////////////////
+//                           directory entry definitions
+///////////////////////////////////////////////////////////////////////////////
+
+error_code directory_entry::__do_refresh() noexcept {
+  __data_.__reset();
+  error_code failure_ec;
+
+  StatT full_st;
+  file_status st = detail::posix_lstat(__p_, full_st, &failure_ec);
+  if (!status_known(st)) {
+    __data_.__reset();
+    return failure_ec;
+  }
+
+  if (!_VSTD_FS::exists(st) || !_VSTD_FS::is_symlink(st)) {
+    __data_.__cache_type_ = directory_entry::_RefreshNonSymlink;
+    __data_.__type_ = st.type();
+    __data_.__non_sym_perms_ = st.permissions();
+  } else { // we have a symlink
+    __data_.__sym_perms_ = st.permissions();
+    // Get the information about the linked entity.
+    // Ignore errors from stat, since we don't want errors regarding symlink
+    // resolution to be reported to the user.
+    error_code ignored_ec;
+    st = detail::posix_stat(__p_, full_st, &ignored_ec);
+
+    __data_.__type_ = st.type();
+    __data_.__non_sym_perms_ = st.permissions();
+
+    // If we failed to resolve the link, then only partially populate the
+    // cache.
+    if (!status_known(st)) {
+      __data_.__cache_type_ = directory_entry::_RefreshSymlinkUnresolved;
+      return error_code{};
+    }
+    // Otherwise, we resolved the link, potentially as not existing.
+    // That's OK.
+    __data_.__cache_type_ = directory_entry::_RefreshSymlink;
+  }
+
+  if (_VSTD_FS::is_regular_file(st))
+    __data_.__size_ = static_cast<uintmax_t>(full_st.st_size);
+
+  if (_VSTD_FS::exists(st)) {
+    __data_.__nlink_ = static_cast<uintmax_t>(full_st.st_nlink);
+
+    // Attempt to extract the mtime, and fail if it's not representable using
+    // file_time_type. For now we ignore the error, as we'll report it when
+    // the value is actually used.
+    error_code ignored_ec;
+    __data_.__write_time_ =
+        __extract_last_write_time(__p_, full_st, &ignored_ec);
+  }
+
+  return failure_ec;
+}
+
+_LIBCPP_END_NAMESPACE_FILESYSTEM
diff --git a/contrib/libs/cxxsupp/libcxx/src/filesystem/posix_compat.h b/contrib/libs/cxxsupp/libcxx/src/filesystem/posix_compat.h
new file mode 100644
index 00000000000..f5c8ec39df2
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/filesystem/posix_compat.h
@@ -0,0 +1,521 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+//
+// POSIX-like portability helper functions.
+//
+// These generally behave like the proper posix functions, with these
+// exceptions:
+// On Windows, they take paths in wchar_t* form, instead of char* form.
+// The symlink() function is split into two frontends, symlink_file()
+// and symlink_dir().
+//
+// These are provided within an anonymous namespace within the detail
+// namespace - callers need to include this header and call them as
+// detail::function(), regardless of platform.
+//
+
+#ifndef POSIX_COMPAT_H
+#define POSIX_COMPAT_H
+
+#include "filesystem"
+
+#include "filesystem_common.h"
+
+#if defined(_LIBCPP_WIN32API)
+# define WIN32_LEAN_AND_MEAN
+# define NOMINMAX
+# include <windows.h>
+# include <io.h>
+# include <winioctl.h>
+#else
+# include <unistd.h>
+# include <sys/stat.h>
+# include <sys/statvfs.h>
+#endif
+#include <time.h>
+
+#if defined(_LIBCPP_WIN32API)
+// This struct isn't defined in the normal Windows SDK, but only in the
+// Windows Driver Kit.
+struct LIBCPP_REPARSE_DATA_BUFFER {
+  unsigned long  ReparseTag;
+  unsigned short ReparseDataLength;
+  unsigned short Reserved;
+  union {
+    struct {
+      unsigned short SubstituteNameOffset;
+      unsigned short SubstituteNameLength;
+      unsigned short PrintNameOffset;
+      unsigned short PrintNameLength;
+      unsigned long  Flags;
+      wchar_t        PathBuffer[1];
+    } SymbolicLinkReparseBuffer;
+    struct {
+      unsigned short SubstituteNameOffset;
+      unsigned short SubstituteNameLength;
+      unsigned short PrintNameOffset;
+      unsigned short PrintNameLength;
+      wchar_t        PathBuffer[1];
+    } MountPointReparseBuffer;
+    struct {
+      unsigned char DataBuffer[1];
+    } GenericReparseBuffer;
+  };
+};
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
+
+namespace detail {
+namespace {
+
+#if defined(_LIBCPP_WIN32API)
+
+// Various C runtime header sets provide more or less of these. As we
+// provide our own implementation, undef all potential defines from the
+// C runtime headers and provide a complete set of macros of our own.
+
+#undef _S_IFMT
+#undef _S_IFDIR
+#undef _S_IFCHR
+#undef _S_IFIFO
+#undef _S_IFREG
+#undef _S_IFBLK
+#undef _S_IFLNK
+#undef _S_IFSOCK
+
+#define _S_IFMT   0xF000
+#define _S_IFDIR  0x4000
+#define _S_IFCHR  0x2000
+#define _S_IFIFO  0x1000
+#define _S_IFREG  0x8000
+#define _S_IFBLK  0x6000
+#define _S_IFLNK  0xA000
+#define _S_IFSOCK 0xC000
+
+#undef S_ISDIR
+#undef S_ISFIFO
+#undef S_ISCHR
+#undef S_ISREG
+#undef S_ISLNK
+#undef S_ISBLK
+#undef S_ISSOCK
+
+#define S_ISDIR(m)      (((m) & _S_IFMT) == _S_IFDIR)
+#define S_ISCHR(m)      (((m) & _S_IFMT) == _S_IFCHR)
+#define S_ISFIFO(m)     (((m) & _S_IFMT) == _S_IFIFO)
+#define S_ISREG(m)      (((m) & _S_IFMT) == _S_IFREG)
+#define S_ISBLK(m)      (((m) & _S_IFMT) == _S_IFBLK)
+#define S_ISLNK(m)      (((m) & _S_IFMT) == _S_IFLNK)
+#define S_ISSOCK(m)     (((m) & _S_IFMT) == _S_IFSOCK)
+
+#define O_NONBLOCK 0
+
+
+// There were 369 years and 89 leap days from the Windows epoch
+// (1601) to the Unix epoch (1970).
+#define FILE_TIME_OFFSET_SECS (uint64_t(369 * 365 + 89) * (24 * 60 * 60))
+
+TimeSpec filetime_to_timespec(LARGE_INTEGER li) {
+  TimeSpec ret;
+  ret.tv_sec = li.QuadPart / 10000000 - FILE_TIME_OFFSET_SECS;
+  ret.tv_nsec = (li.QuadPart % 10000000) * 100;
+  return ret;
+}
+
+TimeSpec filetime_to_timespec(FILETIME ft) {
+  LARGE_INTEGER li;
+  li.LowPart = ft.dwLowDateTime;
+  li.HighPart = ft.dwHighDateTime;
+  return filetime_to_timespec(li);
+}
+
+FILETIME timespec_to_filetime(TimeSpec ts) {
+  LARGE_INTEGER li;
+  li.QuadPart =
+      ts.tv_nsec / 100 + (ts.tv_sec + FILE_TIME_OFFSET_SECS) * 10000000;
+  FILETIME ft;
+  ft.dwLowDateTime = li.LowPart;
+  ft.dwHighDateTime = li.HighPart;
+  return ft;
+}
+
+int set_errno(int e = GetLastError()) {
+  errno = static_cast<int>(__win_err_to_errc(e));
+  return -1;
+}
+
+class WinHandle {
+public:
+  WinHandle(const wchar_t *p, DWORD access, DWORD flags) {
+    h = CreateFileW(
+        p, access, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+        nullptr, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | flags, nullptr);
+  }
+  ~WinHandle() {
+    if (h != INVALID_HANDLE_VALUE)
+      CloseHandle(h);
+  }
+  operator HANDLE() const { return h; }
+  operator bool() const { return h != INVALID_HANDLE_VALUE; }
+
+private:
+  HANDLE h;
+};
+
+int stat_handle(HANDLE h, StatT *buf) {
+  FILE_BASIC_INFO basic;
+  if (!GetFileInformationByHandleEx(h, FileBasicInfo, &basic, sizeof(basic)))
+    return set_errno();
+  memset(buf, 0, sizeof(*buf));
+  buf->st_mtim = filetime_to_timespec(basic.LastWriteTime);
+  buf->st_atim = filetime_to_timespec(basic.LastAccessTime);
+  buf->st_mode = 0555; // Read-only
+  if (!(basic.FileAttributes & FILE_ATTRIBUTE_READONLY))
+    buf->st_mode |= 0222; // Write
+  if (basic.FileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
+    buf->st_mode |= _S_IFDIR;
+  } else {
+    buf->st_mode |= _S_IFREG;
+  }
+  if (basic.FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
+    FILE_ATTRIBUTE_TAG_INFO tag;
+    if (!GetFileInformationByHandleEx(h, FileAttributeTagInfo, &tag,
+                                      sizeof(tag)))
+      return set_errno();
+    if (tag.ReparseTag == IO_REPARSE_TAG_SYMLINK)
+      buf->st_mode = (buf->st_mode & ~_S_IFMT) | _S_IFLNK;
+  }
+  FILE_STANDARD_INFO standard;
+  if (!GetFileInformationByHandleEx(h, FileStandardInfo, &standard,
+                                    sizeof(standard)))
+    return set_errno();
+  buf->st_nlink = standard.NumberOfLinks;
+  buf->st_size = standard.EndOfFile.QuadPart;
+  BY_HANDLE_FILE_INFORMATION info;
+  if (!GetFileInformationByHandle(h, &info))
+    return set_errno();
+  buf->st_dev = info.dwVolumeSerialNumber;
+  memcpy(&buf->st_ino.id[0], &info.nFileIndexHigh, 4);
+  memcpy(&buf->st_ino.id[4], &info.nFileIndexLow, 4);
+  return 0;
+}
+
+int stat_file(const wchar_t *path, StatT *buf, DWORD flags) {
+  WinHandle h(path, FILE_READ_ATTRIBUTES, flags);
+  if (!h)
+    return set_errno();
+  int ret = stat_handle(h, buf);
+  return ret;
+}
+
+int stat(const wchar_t *path, StatT *buf) { return stat_file(path, buf, 0); }
+
+int lstat(const wchar_t *path, StatT *buf) {
+  return stat_file(path, buf, FILE_FLAG_OPEN_REPARSE_POINT);
+}
+
+int fstat(int fd, StatT *buf) {
+  HANDLE h = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
+  return stat_handle(h, buf);
+}
+
+int mkdir(const wchar_t *path, int permissions) {
+  (void)permissions;
+  return _wmkdir(path);
+}
+
+int symlink_file_dir(const wchar_t *oldname, const wchar_t *newname,
+                     bool is_dir) {
+  path dest(oldname);
+  dest.make_preferred();
+  oldname = dest.c_str();
+  DWORD flags = is_dir ? SYMBOLIC_LINK_FLAG_DIRECTORY : 0;
+  if (CreateSymbolicLinkW(newname, oldname,
+                          flags | SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE))
+    return 0;
+  int e = GetLastError();
+  if (e != ERROR_INVALID_PARAMETER)
+    return set_errno(e);
+  if (CreateSymbolicLinkW(newname, oldname, flags))
+    return 0;
+  return set_errno();
+}
+
+int symlink_file(const wchar_t *oldname, const wchar_t *newname) {
+  return symlink_file_dir(oldname, newname, false);
+}
+
+int symlink_dir(const wchar_t *oldname, const wchar_t *newname) {
+  return symlink_file_dir(oldname, newname, true);
+}
+
+int link(const wchar_t *oldname, const wchar_t *newname) {
+  if (CreateHardLinkW(newname, oldname, nullptr))
+    return 0;
+  return set_errno();
+}
+
+int remove(const wchar_t *path) {
+  detail::WinHandle h(path, DELETE, FILE_FLAG_OPEN_REPARSE_POINT);
+  if (!h)
+    return set_errno();
+  FILE_DISPOSITION_INFO info;
+  info.DeleteFile = TRUE;
+  if (!SetFileInformationByHandle(h, FileDispositionInfo, &info, sizeof(info)))
+    return set_errno();
+  return 0;
+}
+
+int truncate_handle(HANDLE h, off_t length) {
+  LARGE_INTEGER size_param;
+  size_param.QuadPart = length;
+  if (!SetFilePointerEx(h, size_param, 0, FILE_BEGIN))
+    return set_errno();
+  if (!SetEndOfFile(h))
+    return set_errno();
+  return 0;
+}
+
+int ftruncate(int fd, off_t length) {
+  HANDLE h = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
+  return truncate_handle(h, length);
+}
+
+int truncate(const wchar_t *path, off_t length) {
+  detail::WinHandle h(path, GENERIC_WRITE, 0);
+  if (!h)
+    return set_errno();
+  return truncate_handle(h, length);
+}
+
+int rename(const wchar_t *from, const wchar_t *to) {
+  if (!(MoveFileExW(from, to,
+                    MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING |
+                        MOVEFILE_WRITE_THROUGH)))
+    return set_errno();
+  return 0;
+}
+
+template <class... Args> int open(const wchar_t *filename, Args... args) {
+  return _wopen(filename, args...);
+}
+int close(int fd) { return _close(fd); }
+int chdir(const wchar_t *path) { return _wchdir(path); }
+
+struct StatVFS {
+  uint64_t f_frsize;
+  uint64_t f_blocks;
+  uint64_t f_bfree;
+  uint64_t f_bavail;
+};
+
+int statvfs(const wchar_t *p, StatVFS *buf) {
+  path dir = p;
+  while (true) {
+    error_code local_ec;
+    const file_status st = status(dir, local_ec);
+    if (!exists(st) || is_directory(st))
+      break;
+    path parent = dir.parent_path();
+    if (parent == dir) {
+      errno = ENOENT;
+      return -1;
+    }
+    dir = parent;
+  }
+  ULARGE_INTEGER free_bytes_available_to_caller, total_number_of_bytes,
+      total_number_of_free_bytes;
+  if (!GetDiskFreeSpaceExW(dir.c_str(), &free_bytes_available_to_caller,
+                           &total_number_of_bytes, &total_number_of_free_bytes))
+    return set_errno();
+  buf->f_frsize = 1;
+  buf->f_blocks = total_number_of_bytes.QuadPart;
+  buf->f_bfree = total_number_of_free_bytes.QuadPart;
+  buf->f_bavail = free_bytes_available_to_caller.QuadPart;
+  return 0;
+}
+
+wchar_t *getcwd(wchar_t *buff, size_t size) { return _wgetcwd(buff, size); }
+
+wchar_t *realpath(const wchar_t *path, wchar_t *resolved_name) {
+  // Only expected to be used with us allocating the buffer.
+  _LIBCPP_ASSERT(resolved_name == nullptr,
+                 "Windows realpath() assumes a null resolved_name");
+
+  WinHandle h(path, FILE_READ_ATTRIBUTES, 0);
+  if (!h) {
+    set_errno();
+    return nullptr;
+  }
+  size_t buff_size = MAX_PATH + 10;
+  std::unique_ptr<wchar_t, decltype(&::free)> buff(
+      static_cast<wchar_t *>(malloc(buff_size * sizeof(wchar_t))), &::free);
+  DWORD retval = GetFinalPathNameByHandleW(
+      h, buff.get(), buff_size, FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
+  if (retval > buff_size) {
+    buff_size = retval;
+    buff.reset(static_cast<wchar_t *>(malloc(buff_size * sizeof(wchar_t))));
+    retval = GetFinalPathNameByHandleW(h, buff.get(), buff_size,
+                                       FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
+  }
+  if (!retval) {
+    set_errno();
+    return nullptr;
+  }
+  wchar_t *ptr = buff.get();
+  if (!wcsncmp(ptr, L"\\\\?\\", 4)) {
+    if (ptr[5] == ':') { // \\?\X: -> X:
+      memmove(&ptr[0], &ptr[4], (wcslen(&ptr[4]) + 1) * sizeof(wchar_t));
+    } else if (!wcsncmp(&ptr[4], L"UNC\\", 4)) { // \\?\UNC\server -> \\server
+      wcscpy(&ptr[0], L"\\\\");
+      memmove(&ptr[2], &ptr[8], (wcslen(&ptr[8]) + 1) * sizeof(wchar_t));
+    }
+  }
+  return buff.release();
+}
+
+#define AT_FDCWD -1
+#define AT_SYMLINK_NOFOLLOW 1
+using ModeT = int;
+
+int fchmod_handle(HANDLE h, int perms) {
+  FILE_BASIC_INFO basic;
+  if (!GetFileInformationByHandleEx(h, FileBasicInfo, &basic, sizeof(basic)))
+    return set_errno();
+  DWORD orig_attributes = basic.FileAttributes;
+  basic.FileAttributes &= ~FILE_ATTRIBUTE_READONLY;
+  if ((perms & 0222) == 0)
+    basic.FileAttributes |= FILE_ATTRIBUTE_READONLY;
+  if (basic.FileAttributes != orig_attributes &&
+      !SetFileInformationByHandle(h, FileBasicInfo, &basic, sizeof(basic)))
+    return set_errno();
+  return 0;
+}
+
+int fchmodat(int fd, const wchar_t *path, int perms, int flag) {
+  DWORD attributes = GetFileAttributesW(path);
+  if (attributes == INVALID_FILE_ATTRIBUTES)
+    return set_errno();
+  if (attributes & FILE_ATTRIBUTE_REPARSE_POINT &&
+      !(flag & AT_SYMLINK_NOFOLLOW)) {
+    // If the file is a symlink, and we are supposed to operate on the target
+    // of the symlink, we need to open a handle to it, without the
+    // FILE_FLAG_OPEN_REPARSE_POINT flag, to open the destination of the
+    // symlink, and operate on it via the handle.
+    detail::WinHandle h(path, FILE_READ_ATTRIBUTES | FILE_WRITE_ATTRIBUTES, 0);
+    if (!h)
+      return set_errno();
+    return fchmod_handle(h, perms);
+  } else {
+    // For a non-symlink, or if operating on the symlink itself instead of
+    // its target, we can use SetFileAttributesW, saving a few calls.
+    DWORD orig_attributes = attributes;
+    attributes &= ~FILE_ATTRIBUTE_READONLY;
+    if ((perms & 0222) == 0)
+      attributes |= FILE_ATTRIBUTE_READONLY;
+    if (attributes != orig_attributes && !SetFileAttributesW(path, attributes))
+      return set_errno();
+  }
+  return 0;
+}
+
+int fchmod(int fd, int perms) {
+  HANDLE h = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
+  return fchmod_handle(h, perms);
+}
+
+#define MAX_SYMLINK_SIZE MAXIMUM_REPARSE_DATA_BUFFER_SIZE
+using SSizeT = ::int64_t;
+
+SSizeT readlink(const wchar_t *path, wchar_t *ret_buf, size_t bufsize) {
+  uint8_t buf[MAXIMUM_REPARSE_DATA_BUFFER_SIZE];
+  detail::WinHandle h(path, FILE_READ_ATTRIBUTES, FILE_FLAG_OPEN_REPARSE_POINT);
+  if (!h)
+    return set_errno();
+  DWORD out;
+  if (!DeviceIoControl(h, FSCTL_GET_REPARSE_POINT, nullptr, 0, buf, sizeof(buf),
+                       &out, 0))
+    return set_errno();
+  const auto *reparse = reinterpret_cast<LIBCPP_REPARSE_DATA_BUFFER *>(buf);
+  size_t path_buf_offset = offsetof(LIBCPP_REPARSE_DATA_BUFFER,
+                                    SymbolicLinkReparseBuffer.PathBuffer[0]);
+  if (out < path_buf_offset) {
+    errno = EINVAL;
+    return -1;
+  }
+  if (reparse->ReparseTag != IO_REPARSE_TAG_SYMLINK) {
+    errno = EINVAL;
+    return -1;
+  }
+  const auto &symlink = reparse->SymbolicLinkReparseBuffer;
+  unsigned short name_offset, name_length;
+  if (symlink.PrintNameLength == 0) {
+    name_offset = symlink.SubstituteNameOffset;
+    name_length = symlink.SubstituteNameLength;
+  } else {
+    name_offset = symlink.PrintNameOffset;
+    name_length = symlink.PrintNameLength;
+  }
+  // name_offset/length are expressed in bytes, not in wchar_t
+  if (path_buf_offset + name_offset + name_length > out) {
+    errno = EINVAL;
+    return -1;
+  }
+  if (name_length / sizeof(wchar_t) > bufsize) {
+    errno = ENOMEM;
+    return -1;
+  }
+  memcpy(ret_buf, &symlink.PathBuffer[name_offset / sizeof(wchar_t)],
+         name_length);
+  return name_length / sizeof(wchar_t);
+}
+
+#else
+int symlink_file(const char *oldname, const char *newname) {
+  return ::symlink(oldname, newname);
+}
+int symlink_dir(const char *oldname, const char *newname) {
+  return ::symlink(oldname, newname);
+}
+using ::chdir;
+using ::close;
+using ::fchmod;
+#if defined(AT_SYMLINK_NOFOLLOW) && defined(AT_FDCWD)
+using ::fchmodat;
+#endif
+using ::fstat;
+using ::ftruncate;
+using ::getcwd;
+using ::link;
+using ::lstat;
+using ::mkdir;
+using ::open;
+using ::readlink;
+using ::realpath;
+using ::remove;
+using ::rename;
+using ::stat;
+using ::statvfs;
+using ::truncate;
+
+#define O_BINARY 0
+
+using StatVFS = struct statvfs;
+using ModeT = ::mode_t;
+using SSizeT = ::ssize_t;
+
+#endif
+
+} // namespace
+} // end namespace detail
+
+_LIBCPP_END_NAMESPACE_FILESYSTEM
+
+#endif // POSIX_COMPAT_H
diff --git a/contrib/libs/cxxsupp/libcxx/src/format.cpp b/contrib/libs/cxxsupp/libcxx/src/format.cpp
new file mode 100644
index 00000000000..c36c20e60a9
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/format.cpp
@@ -0,0 +1,19 @@
+//===------------------------- format.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "format"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+format_error::~format_error() noexcept = default;
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/functional.cpp b/contrib/libs/cxxsupp/libcxx/src/functional.cpp
new file mode 100644
index 00000000000..cc5f43a9f2e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/functional.cpp
@@ -0,0 +1,25 @@
+//===----------------------- functional.cpp -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "functional"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifdef _LIBCPP_ABI_BAD_FUNCTION_CALL_KEY_FUNCTION
+bad_function_call::~bad_function_call() noexcept
+{
+}
+
+const char*
+bad_function_call::what() const noexcept
+{
+    return "std::bad_function_call";
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/future.cpp b/contrib/libs/cxxsupp/libcxx/src/future.cpp
new file mode 100644
index 00000000000..4c59f89e56a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/future.cpp
@@ -0,0 +1,277 @@
+//===------------------------- future.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "__config"
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+
+#include "future"
+#include "string"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+class _LIBCPP_HIDDEN __future_error_category
+    : public __do_message
+{
+public:
+    virtual const char* name() const noexcept;
+    virtual string message(int ev) const;
+};
+
+const char*
+__future_error_category::name() const noexcept
+{
+    return "future";
+}
+
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wswitch"
+#elif defined(__GNUC__) || defined(__GNUG__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wswitch"
+#endif
+
+string
+__future_error_category::message(int ev) const
+{
+    switch (static_cast<future_errc>(ev))
+    {
+    case future_errc(0):  // For backwards compatibility with C++11 (LWG 2056)
+    case future_errc::broken_promise:
+        return string("The associated promise has been destructed prior "
+                      "to the associated state becoming ready.");
+    case future_errc::future_already_retrieved:
+        return string("The future has already been retrieved from "
+                      "the promise or packaged_task.");
+    case future_errc::promise_already_satisfied:
+        return string("The state of the promise has already been set.");
+    case future_errc::no_state:
+        return string("Operation not permitted on an object without "
+                      "an associated state.");
+    }
+    return string("unspecified future_errc value\n");
+}
+
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#elif defined(__GNUC__) || defined(__GNUG__)
+#pragma GCC diagnostic pop
+#endif
+
+const error_category&
+future_category() noexcept
+{
+    static __future_error_category __f;
+    return __f;
+}
+
+future_error::future_error(error_code __ec)
+    : logic_error(__ec.message()),
+      __ec_(__ec)
+{
+}
+
+future_error::~future_error() noexcept
+{
+}
+
+void
+__assoc_sub_state::__on_zero_shared() noexcept
+{
+    delete this;
+}
+
+void
+__assoc_sub_state::set_value()
+{
+    unique_lock<mutex> __lk(__mut_);
+    if (__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+    __state_ |= __constructed | ready;
+    __cv_.notify_all();
+}
+
+void
+__assoc_sub_state::set_value_at_thread_exit()
+{
+    unique_lock<mutex> __lk(__mut_);
+    if (__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+    __state_ |= __constructed;
+    __thread_local_data()->__make_ready_at_thread_exit(this);
+}
+
+void
+__assoc_sub_state::set_exception(exception_ptr __p)
+{
+    unique_lock<mutex> __lk(__mut_);
+    if (__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+    __exception_ = __p;
+    __state_ |= ready;
+    __cv_.notify_all();
+}
+
+void
+__assoc_sub_state::set_exception_at_thread_exit(exception_ptr __p)
+{
+    unique_lock<mutex> __lk(__mut_);
+    if (__has_value())
+        __throw_future_error(future_errc::promise_already_satisfied);
+    __exception_ = __p;
+    __thread_local_data()->__make_ready_at_thread_exit(this);
+}
+
+void
+__assoc_sub_state::__make_ready()
+{
+    unique_lock<mutex> __lk(__mut_);
+    __state_ |= ready;
+    __cv_.notify_all();
+}
+
+void
+__assoc_sub_state::copy()
+{
+    unique_lock<mutex> __lk(__mut_);
+    __sub_wait(__lk);
+    if (__exception_ != nullptr)
+        rethrow_exception(__exception_);
+}
+
+void
+__assoc_sub_state::wait()
+{
+    unique_lock<mutex> __lk(__mut_);
+    __sub_wait(__lk);
+}
+
+void
+__assoc_sub_state::__sub_wait(unique_lock<mutex>& __lk)
+{
+    if (!__is_ready())
+    {
+        if (__state_ & static_cast<unsigned>(deferred))
+        {
+            __state_ &= ~static_cast<unsigned>(deferred);
+            __lk.unlock();
+            __execute();
+        }
+        else
+            while (!__is_ready())
+                __cv_.wait(__lk);
+    }
+}
+
+void
+__assoc_sub_state::__execute()
+{
+    __throw_future_error(future_errc::no_state);
+}
+
+future<void>::future(__assoc_sub_state* __state)
+    : __state_(__state)
+{
+    __state_->__attach_future();
+}
+
+future<void>::~future()
+{
+    if (__state_)
+        __state_->__release_shared();
+}
+
+void
+future<void>::get()
+{
+    unique_ptr<__shared_count, __release_shared_count> __(__state_);
+    __assoc_sub_state* __s = __state_;
+    __state_ = nullptr;
+    __s->copy();
+}
+
+promise<void>::promise()
+    : __state_(new __assoc_sub_state)
+{
+}
+
+promise<void>::~promise()
+{
+    if (__state_)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        if (!__state_->__has_value() && __state_->use_count() > 1)
+            __state_->set_exception(make_exception_ptr(
+                      future_error(make_error_code(future_errc::broken_promise))
+                                                      ));
+#endif // _LIBCPP_NO_EXCEPTIONS
+        __state_->__release_shared();
+    }
+}
+
+future<void>
+promise<void>::get_future()
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    return future<void>(__state_);
+}
+
+void
+promise<void>::set_value()
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_value();
+}
+
+void
+promise<void>::set_exception(exception_ptr __p)
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_exception(__p);
+}
+
+void
+promise<void>::set_value_at_thread_exit()
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_value_at_thread_exit();
+}
+
+void
+promise<void>::set_exception_at_thread_exit(exception_ptr __p)
+{
+    if (__state_ == nullptr)
+        __throw_future_error(future_errc::no_state);
+    __state_->set_exception_at_thread_exit(__p);
+}
+
+shared_future<void>::~shared_future()
+{
+    if (__state_)
+        __state_->__release_shared();
+}
+
+shared_future<void>&
+shared_future<void>::operator=(const shared_future& __rhs)
+{
+    if (__rhs.__state_)
+        __rhs.__state_->__add_shared();
+    if (__state_)
+        __state_->__release_shared();
+    __state_ = __rhs.__state_;
+    return *this;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !_LIBCPP_HAS_NO_THREADS
diff --git a/contrib/libs/cxxsupp/libcxx/src/hash.cpp b/contrib/libs/cxxsupp/libcxx/src/hash.cpp
new file mode 100644
index 00000000000..89bb736c86c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/hash.cpp
@@ -0,0 +1,561 @@
+//===-------------------------- hash.cpp ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "__hash_table"
+#include "algorithm"
+#include "stdexcept"
+#include "type_traits"
+
+#ifdef __clang__
+#pragma clang diagnostic ignored "-Wtautological-constant-out-of-range-compare"
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace {
+
+// handle all next_prime(i) for i in [1, 210), special case 0
+const unsigned small_primes[] =
+{
+    0,
+    2,
+    3,
+    5,
+    7,
+    11,
+    13,
+    17,
+    19,
+    23,
+    29,
+    31,
+    37,
+    41,
+    43,
+    47,
+    53,
+    59,
+    61,
+    67,
+    71,
+    73,
+    79,
+    83,
+    89,
+    97,
+    101,
+    103,
+    107,
+    109,
+    113,
+    127,
+    131,
+    137,
+    139,
+    149,
+    151,
+    157,
+    163,
+    167,
+    173,
+    179,
+    181,
+    191,
+    193,
+    197,
+    199,
+    211
+};
+
+// potential primes = 210*k + indices[i], k >= 1
+//   these numbers are not divisible by 2, 3, 5 or 7
+//   (or any integer 2 <= j <= 10 for that matter).
+const unsigned indices[] =
+{
+    1,
+    11,
+    13,
+    17,
+    19,
+    23,
+    29,
+    31,
+    37,
+    41,
+    43,
+    47,
+    53,
+    59,
+    61,
+    67,
+    71,
+    73,
+    79,
+    83,
+    89,
+    97,
+    101,
+    103,
+    107,
+    109,
+    113,
+    121,
+    127,
+    131,
+    137,
+    139,
+    143,
+    149,
+    151,
+    157,
+    163,
+    167,
+    169,
+    173,
+    179,
+    181,
+    187,
+    191,
+    193,
+    197,
+    199,
+    209
+};
+
+}
+
+// Returns:  If n == 0, returns 0.  Else returns the lowest prime number that
+// is greater than or equal to n.
+//
+// The algorithm creates a list of small primes, plus an open-ended list of
+// potential primes.  All prime numbers are potential prime numbers.  However
+// some potential prime numbers are not prime.  In an ideal world, all potential
+// prime numbers would be prime.  Candidate prime numbers are chosen as the next
+// highest potential prime.  Then this number is tested for prime by dividing it
+// by all potential prime numbers less than the sqrt of the candidate.
+//
+// This implementation defines potential primes as those numbers not divisible
+// by 2, 3, 5, and 7.  Other (common) implementations define potential primes
+// as those not divisible by 2.  A few other implementations define potential
+// primes as those not divisible by 2 or 3.  By raising the number of small
+// primes which the potential prime is not divisible by, the set of potential
+// primes more closely approximates the set of prime numbers.  And thus there
+// are fewer potential primes to search, and fewer potential primes to divide
+// against.
+
+template <size_t _Sz = sizeof(size_t)>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if<_Sz == 4, void>::type
+__check_for_overflow(size_t N)
+{
+    if (N > 0xFFFFFFFB)
+        __throw_overflow_error("__next_prime overflow");
+}
+
+template <size_t _Sz = sizeof(size_t)>
+inline _LIBCPP_INLINE_VISIBILITY
+typename enable_if<_Sz == 8, void>::type
+__check_for_overflow(size_t N)
+{
+    if (N > 0xFFFFFFFFFFFFFFC5ull)
+        __throw_overflow_error("__next_prime overflow");
+}
+
+size_t
+__next_prime(size_t n)
+{
+    const size_t L = 210;
+    const size_t N = sizeof(small_primes) / sizeof(small_primes[0]);
+    // If n is small enough, search in small_primes
+    if (n <= small_primes[N-1])
+        return *std::lower_bound(small_primes, small_primes + N, n);
+    // Else n > largest small_primes
+    // Check for overflow
+    __check_for_overflow(n);
+    // Start searching list of potential primes: L * k0 + indices[in]
+    const size_t M = sizeof(indices) / sizeof(indices[0]);
+    // Select first potential prime >= n
+    //   Known a-priori n >= L
+    size_t k0 = n / L;
+    size_t in = static_cast<size_t>(std::lower_bound(indices, indices + M, n - k0 * L)
+                                    - indices);
+    n = L * k0 + indices[in];
+    while (true)
+    {
+        // Divide n by all primes or potential primes (i) until:
+        //    1.  The division is even, so try next potential prime.
+        //    2.  The i > sqrt(n), in which case n is prime.
+        // It is known a-priori that n is not divisible by 2, 3, 5 or 7,
+        //    so don't test those (j == 5 ->  divide by 11 first).  And the
+        //    potential primes start with 211, so don't test against the last
+        //    small prime.
+        for (size_t j = 5; j < N - 1; ++j)
+        {
+            const std::size_t p = small_primes[j];
+            const std::size_t q = n / p;
+            if (q < p)
+                return n;
+            if (n == q * p)
+                goto next;
+        }
+        // n wasn't divisible by small primes, try potential primes
+        {
+            size_t i = 211;
+            while (true)
+            {
+                std::size_t q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 10;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 8;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 8;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 6;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 4;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 2;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                i += 10;
+                q = n / i;
+                if (q < i)
+                    return n;
+                if (n == q * i)
+                    break;
+
+                // This will loop i to the next "plane" of potential primes
+                i += 2;
+            }
+        }
+next:
+        // n is not prime.  Increment n to next potential prime.
+        if (++in == M)
+        {
+            ++k0;
+            in = 0;
+        }
+        n = L * k0 + indices[in];
+    }
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/include/apple_availability.h b/contrib/libs/cxxsupp/libcxx/src/include/apple_availability.h
new file mode 100644
index 00000000000..0f999d3feaf
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/include/apple_availability.h
@@ -0,0 +1,51 @@
+//===------------------------ apple_availability.h ------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+#ifndef _LIBCPP_SRC_INCLUDE_APPLE_AVAILABILITY_H
+#define _LIBCPP_SRC_INCLUDE_APPLE_AVAILABILITY_H
+
+#if defined(__APPLE__)
+
+#if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__)
+#if __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 101300
+#define _LIBCPP_USE_UTIMENSAT
+#endif
+#elif defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__)
+#if __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ >= 110000
+#define _LIBCPP_USE_UTIMENSAT
+#endif
+#elif defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__)
+#if __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ >= 110000
+#define _LIBCPP_USE_UTIMENSAT
+#endif
+#elif defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__)
+#if __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ >= 40000
+#define _LIBCPP_USE_UTIMENSAT
+#endif
+#endif // __ENVIRONMENT_.*_VERSION_MIN_REQUIRED__
+
+#if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__)
+#if __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 101500
+#define _LIBCPP_USE_ULOCK
+#endif
+#elif defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__)
+#if __ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__ >= 130000
+#define _LIBCPP_USE_ULOCK
+#endif
+#elif defined(__ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__)
+#if __ENVIRONMENT_TV_OS_VERSION_MIN_REQUIRED__ >= 130000
+#define _LIBCPP_USE_ULOCK
+#endif
+#elif defined(__ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__)
+#if __ENVIRONMENT_WATCH_OS_VERSION_MIN_REQUIRED__ >= 60000
+#define _LIBCPP_USE_ULOCK
+#endif
+#endif // __ENVIRONMENT_.*_VERSION_MIN_REQUIRED__
+
+#endif // __APPLE__
+
+#endif // _LIBCPP_SRC_INCLUDE_APPLE_AVAILABILITY_H
diff --git a/contrib/libs/cxxsupp/libcxx/src/include/atomic_support.h b/contrib/libs/cxxsupp/libcxx/src/include/atomic_support.h
new file mode 100644
index 00000000000..5a745a2f009
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/include/atomic_support.h
@@ -0,0 +1,176 @@
+//===----------------------------------------------------------------------===////
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===////
+
+#ifndef ATOMIC_SUPPORT_H
+#define ATOMIC_SUPPORT_H
+
+#include "__config"
+#include "memory" // for __libcpp_relaxed_load
+
+#if defined(__clang__) && __has_builtin(__atomic_load_n)             \
+                       && __has_builtin(__atomic_store_n)            \
+                       && __has_builtin(__atomic_add_fetch)          \
+                       && __has_builtin(__atomic_exchange_n)         \
+                       && __has_builtin(__atomic_compare_exchange_n) \
+                       && defined(__ATOMIC_RELAXED)                  \
+                       && defined(__ATOMIC_CONSUME)                  \
+                       && defined(__ATOMIC_ACQUIRE)                  \
+                       && defined(__ATOMIC_RELEASE)                  \
+                       && defined(__ATOMIC_ACQ_REL)                  \
+                       && defined(__ATOMIC_SEQ_CST)
+#   define _LIBCPP_HAS_ATOMIC_BUILTINS
+#elif defined(_LIBCPP_COMPILER_GCC)
+#   define _LIBCPP_HAS_ATOMIC_BUILTINS
+#endif
+
+#if !defined(_LIBCPP_HAS_ATOMIC_BUILTINS) && !defined(_LIBCPP_HAS_NO_THREADS)
+# if defined(_LIBCPP_WARNING)
+    _LIBCPP_WARNING("Building libc++ without __atomic builtins is unsupported")
+# else
+#   warning Building libc++ without __atomic builtins is unsupported
+# endif
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace {
+
+#if defined(_LIBCPP_HAS_ATOMIC_BUILTINS) && !defined(_LIBCPP_HAS_NO_THREADS)
+
+enum __libcpp_atomic_order {
+    _AO_Relaxed = __ATOMIC_RELAXED,
+    _AO_Consume = __ATOMIC_CONSUME,
+    _AO_Acquire = __ATOMIC_ACQUIRE,
+    _AO_Release = __ATOMIC_RELEASE,
+    _AO_Acq_Rel = __ATOMIC_ACQ_REL,
+    _AO_Seq     = __ATOMIC_SEQ_CST
+};
+
+template <class _ValueType, class _FromType>
+inline _LIBCPP_INLINE_VISIBILITY
+void __libcpp_atomic_store(_ValueType* __dest, _FromType __val,
+                           int __order = _AO_Seq)
+{
+    __atomic_store_n(__dest, __val, __order);
+}
+
+template <class _ValueType, class _FromType>
+inline _LIBCPP_INLINE_VISIBILITY
+void __libcpp_relaxed_store(_ValueType* __dest, _FromType __val)
+{
+    __atomic_store_n(__dest, __val, _AO_Relaxed);
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+_ValueType __libcpp_atomic_load(_ValueType const* __val,
+                                int __order = _AO_Seq)
+{
+    return __atomic_load_n(__val, __order);
+}
+
+template <class _ValueType, class _AddType>
+inline _LIBCPP_INLINE_VISIBILITY
+_ValueType __libcpp_atomic_add(_ValueType* __val, _AddType __a,
+                               int __order = _AO_Seq)
+{
+    return __atomic_add_fetch(__val, __a, __order);
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+_ValueType __libcpp_atomic_exchange(_ValueType* __target,
+                                    _ValueType __value, int __order = _AO_Seq)
+{
+    return __atomic_exchange_n(__target, __value, __order);
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+bool __libcpp_atomic_compare_exchange(_ValueType* __val,
+    _ValueType* __expected, _ValueType __after,
+    int __success_order = _AO_Seq,
+    int __fail_order = _AO_Seq)
+{
+    return __atomic_compare_exchange_n(__val, __expected, __after, true,
+                                       __success_order, __fail_order);
+}
+
+#else // _LIBCPP_HAS_NO_THREADS
+
+enum __libcpp_atomic_order {
+    _AO_Relaxed,
+    _AO_Consume,
+    _AO_Acquire,
+    _AO_Release,
+    _AO_Acq_Rel,
+    _AO_Seq
+};
+
+template <class _ValueType, class _FromType>
+inline _LIBCPP_INLINE_VISIBILITY
+void __libcpp_atomic_store(_ValueType* __dest, _FromType __val,
+                           int = 0)
+{
+    *__dest = __val;
+}
+
+template <class _ValueType, class _FromType>
+inline _LIBCPP_INLINE_VISIBILITY
+void __libcpp_relaxed_store(_ValueType* __dest, _FromType __val)
+{
+    *__dest = __val;
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+_ValueType __libcpp_atomic_load(_ValueType const* __val,
+                                int = 0)
+{
+    return *__val;
+}
+
+template <class _ValueType, class _AddType>
+inline _LIBCPP_INLINE_VISIBILITY
+_ValueType __libcpp_atomic_add(_ValueType* __val, _AddType __a,
+                               int = 0)
+{
+    return *__val += __a;
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+_ValueType __libcpp_atomic_exchange(_ValueType* __target,
+                                    _ValueType __value, int = _AO_Seq)
+{
+    _ValueType old = *__target;
+    *__target = __value;
+    return old;
+}
+
+template <class _ValueType>
+inline _LIBCPP_INLINE_VISIBILITY
+bool __libcpp_atomic_compare_exchange(_ValueType* __val,
+    _ValueType* __expected, _ValueType __after,
+    int = 0, int = 0)
+{
+    if (*__val == *__expected) {
+        *__val = __after;
+        return true;
+    }
+    *__expected = *__val;
+    return false;
+}
+
+#endif // _LIBCPP_HAS_NO_THREADS
+
+} // end namespace
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // ATOMIC_SUPPORT_H
diff --git a/contrib/libs/cxxsupp/libcxx/src/include/config_elast.h b/contrib/libs/cxxsupp/libcxx/src/include/config_elast.h
new file mode 100644
index 00000000000..7880c733fb8
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/include/config_elast.h
@@ -0,0 +1,49 @@
+//===----------------------- config_elast.h -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_CONFIG_ELAST
+#define _LIBCPP_CONFIG_ELAST
+
+#include <__config>
+
+#if defined(_LIBCPP_MSVCRT_LIKE)
+#include <stdlib.h>
+#else
+#include <errno.h>
+#endif
+
+// Note: _LIBCPP_ELAST needs to be defined only on platforms
+// where strerror/strerror_r can't handle out-of-range errno values.
+#if defined(ELAST)
+#define _LIBCPP_ELAST ELAST
+#elif defined(_NEWLIB_VERSION)
+#define _LIBCPP_ELAST __ELASTERROR
+#elif defined(__NuttX__)
+// No _LIBCPP_ELAST needed on NuttX
+#elif defined(__Fuchsia__)
+// No _LIBCPP_ELAST needed on Fuchsia
+#elif defined(__wasi__)
+// No _LIBCPP_ELAST needed on WASI
+#elif defined(__linux__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+#define _LIBCPP_ELAST 4095
+#elif defined(__APPLE__)
+// No _LIBCPP_ELAST needed on Apple
+#elif defined(__sun__)
+#define _LIBCPP_ELAST ESTALE
+#elif defined(__MVS__)
+#define _LIBCPP_ELAST 1160
+#elif defined(_LIBCPP_MSVCRT_LIKE)
+#define _LIBCPP_ELAST (_sys_nerr - 1)
+#elif defined(_AIX)
+#define _LIBCPP_ELAST 127
+#else
+// Warn here so that the person doing the libcxx port has an easier time:
+#warning ELAST for this platform not yet implemented
+#endif
+
+#endif // _LIBCPP_CONFIG_ELAST
diff --git a/contrib/libs/cxxsupp/libcxx/src/include/refstring.h b/contrib/libs/cxxsupp/libcxx/src/include/refstring.h
new file mode 100644
index 00000000000..3edd240a5d6
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/include/refstring.h
@@ -0,0 +1,167 @@
+//===------------------------ __refstring ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_REFSTRING_H
+#define _LIBCPP_REFSTRING_H
+
+#include <__config>
+#include <stdexcept>
+#include <cstddef>
+#include <cstring>
+
+#if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_CXX03_LANG) && !defined(_LIBCPP_USE_ATOMIC)
+#define _LIBCPP_USE_ATOMIC
+#include <atomic>
+#else
+#include "atomic_support.h"
+#endif
+
+// MacOS and iOS used to ship with libstdc++, and still support old applications
+// linking against libstdc++. The libc++ and libstdc++ exceptions are supposed
+// to be ABI compatible, such that they can be thrown from one library and caught
+// in the other.
+//
+// For that reason, we must look for libstdc++ in the same process and if found,
+// check the string stored in the exception object to see if it is the GCC empty
+// string singleton before manipulating the reference count. This is done so that
+// if an exception is created with a zero-length string in libstdc++, libc++abi
+// won't try to delete the memory.
+#if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) || \
+    defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__)
+#   define _LIBCPP_CHECK_FOR_GCC_EMPTY_STRING_STORAGE
+#   include <dlfcn.h>
+#   include <mach-o/dyld.h>
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace __refstring_imp { namespace {
+typedef int count_t;
+
+struct _Rep_base {
+    std::size_t len;
+    std::size_t cap;
+#ifdef _LIBCPP_USE_ATOMIC
+    std::atomic<count_t> count;
+#else
+    count_t     count;
+#endif
+};
+
+inline _Rep_base* rep_from_data(const char *data_) noexcept {
+    char *data = const_cast<char *>(data_);
+    return reinterpret_cast<_Rep_base *>(data - sizeof(_Rep_base));
+}
+
+inline char * data_from_rep(_Rep_base *rep) noexcept {
+    char *data = reinterpret_cast<char *>(rep);
+    return data + sizeof(*rep);
+}
+
+#if defined(_LIBCPP_CHECK_FOR_GCC_EMPTY_STRING_STORAGE)
+inline
+const char* compute_gcc_empty_string_storage() noexcept
+{
+    void* handle = dlopen("/usr/lib/libstdc++.6.dylib", RTLD_NOLOAD);
+    if (handle == nullptr)
+        return nullptr;
+    void* sym = dlsym(handle, "_ZNSs4_Rep20_S_empty_rep_storageE");
+    if (sym == nullptr)
+        return nullptr;
+    return data_from_rep(reinterpret_cast<_Rep_base *>(sym));
+}
+
+inline
+const char*
+get_gcc_empty_string_storage() noexcept
+{
+    static const char* p = compute_gcc_empty_string_storage();
+    return p;
+}
+#endif
+
+}} // namespace __refstring_imp
+
+using namespace __refstring_imp;
+
+inline
+__libcpp_refstring::__libcpp_refstring(const char* msg) {
+    std::size_t len = strlen(msg);
+    _Rep_base* rep = static_cast<_Rep_base *>(::operator new(sizeof(*rep) + len + 1));
+    rep->len = len;
+    rep->cap = len;
+    rep->count = 0;
+    char *data = data_from_rep(rep);
+    std::memcpy(data, msg, len + 1);
+    __imp_ = data;
+}
+
+inline
+__libcpp_refstring::__libcpp_refstring(const __libcpp_refstring &s) noexcept
+    : __imp_(s.__imp_)
+{
+    if (__uses_refcount())
+#ifdef _LIBCPP_USE_ATOMIC
+        rep_from_data(__imp_)->count.fetch_add(1);
+#else
+        __libcpp_atomic_add(&rep_from_data(__imp_)->count, 1);
+#endif
+}
+
+inline
+__libcpp_refstring& __libcpp_refstring::operator=(__libcpp_refstring const& s) noexcept {
+    bool adjust_old_count = __uses_refcount();
+    struct _Rep_base *old_rep = rep_from_data(__imp_);
+    __imp_ = s.__imp_;
+    if (__uses_refcount())
+#ifdef _LIBCPP_USE_ATOMIC
+        rep_from_data(__imp_)->count.fetch_add(1);
+#else
+        __libcpp_atomic_add(&rep_from_data(__imp_)->count, 1);
+#endif
+
+    if (adjust_old_count)
+    {
+#ifdef _LIBCPP_USE_ATOMIC
+        if (old_rep->count.fetch_sub(1) == 0)
+#else
+        if (__libcpp_atomic_add(&old_rep->count, count_t(-1)) < 0)
+#endif
+        {
+            ::operator delete(old_rep);
+        }
+    }
+    return *this;
+}
+
+inline
+__libcpp_refstring::~__libcpp_refstring() {
+    if (__uses_refcount()) {
+        _Rep_base* rep = rep_from_data(__imp_);
+#ifdef _LIBCPP_USE_ATOMIC
+        if (rep->count.fetch_sub(1) == 0) {
+#else
+        if (__sync_add_and_fetch(&rep->count, count_t(-1)) < 0) {
+#endif
+            ::operator delete(rep);
+        }
+    }
+}
+
+inline
+bool __libcpp_refstring::__uses_refcount() const {
+#if defined(_LIBCPP_CHECK_FOR_GCC_EMPTY_STRING_STORAGE)
+    return __imp_ != get_gcc_empty_string_storage();
+#else
+    return true;
+#endif
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif //_LIBCPP_REFSTRING_H
diff --git a/contrib/libs/cxxsupp/libcxx/src/include/sso_allocator.h b/contrib/libs/cxxsupp/libcxx/src/include/sso_allocator.h
new file mode 100644
index 00000000000..2baf599c5c2
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/include/sso_allocator.h
@@ -0,0 +1,77 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_SSO_ALLOCATOR_H
+#define _LIBCPP_SSO_ALLOCATOR_H
+
+#include <__config>
+#include <memory>
+#include <new>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, size_t _Np> class _LIBCPP_HIDDEN __sso_allocator;
+
+template <size_t _Np>
+class _LIBCPP_HIDDEN __sso_allocator<void, _Np>
+{
+public:
+    typedef const void*       const_pointer;
+    typedef void              value_type;
+};
+
+template <class _Tp, size_t _Np>
+class _LIBCPP_HIDDEN __sso_allocator
+{
+    typename aligned_storage<sizeof(_Tp) * _Np>::type buf_;
+    bool __allocated_;
+public:
+    typedef size_t            size_type;
+    typedef _Tp*              pointer;
+    typedef _Tp               value_type;
+
+    _LIBCPP_INLINE_VISIBILITY __sso_allocator() throw() : __allocated_(false) {}
+    _LIBCPP_INLINE_VISIBILITY __sso_allocator(const __sso_allocator&) throw() : __allocated_(false) {}
+    template <class _Up> _LIBCPP_INLINE_VISIBILITY __sso_allocator(const __sso_allocator<_Up, _Np>&) throw()
+         : __allocated_(false) {}
+private:
+    __sso_allocator& operator=(const __sso_allocator&);
+public:
+    _LIBCPP_INLINE_VISIBILITY pointer allocate(size_type __n, typename __sso_allocator<void, _Np>::const_pointer = nullptr)
+    {
+        if (!__allocated_ && __n <= _Np)
+        {
+            __allocated_ = true;
+            return (pointer)&buf_;
+        }
+        return allocator<_Tp>().allocate(__n);
+    }
+    _LIBCPP_INLINE_VISIBILITY void deallocate(pointer __p, size_type __n)
+    {
+        if (__p == (pointer)&buf_)
+            __allocated_ = false;
+        else
+            allocator<_Tp>().deallocate(__p, __n);
+    }
+    _LIBCPP_INLINE_VISIBILITY size_type max_size() const throw() {return size_type(~0) / sizeof(_Tp);}
+
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator==(const __sso_allocator& __a) const {return &buf_ == &__a.buf_;}
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator!=(const __sso_allocator& __a) const {return &buf_ != &__a.buf_;}
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_SSO_ALLOCATOR_H
diff --git a/contrib/libs/cxxsupp/libcxx/src/ios.cpp b/contrib/libs/cxxsupp/libcxx/src/ios.cpp
new file mode 100644
index 00000000000..a8a99015a97
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/ios.cpp
@@ -0,0 +1,441 @@
+//===-------------------------- ios.cpp -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "__config"
+
+#include "ios"
+
+#include <stdlib.h>
+
+#include "__locale"
+#include "algorithm"
+#include "include/config_elast.h"
+#include "limits"
+#include "memory"
+#include "new"
+#include "string"
+#include "__undef_macros"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+class _LIBCPP_HIDDEN __iostream_category
+    : public __do_message
+{
+public:
+    virtual const char* name() const noexcept;
+    virtual string message(int ev) const;
+};
+
+const char*
+__iostream_category::name() const noexcept
+{
+    return "iostream";
+}
+
+string
+__iostream_category::message(int ev) const
+{
+    if (ev != static_cast<int>(io_errc::stream)
+#ifdef _LIBCPP_ELAST
+        && ev <= _LIBCPP_ELAST
+#endif // _LIBCPP_ELAST
+        )
+        return __do_message::message(ev);
+    return string("unspecified iostream_category error");
+}
+
+const error_category&
+iostream_category() noexcept
+{
+    static __iostream_category s;
+    return s;
+}
+
+// ios_base::failure
+
+ios_base::failure::failure(const string& msg, const error_code& ec)
+    : system_error(ec, msg)
+{
+}
+
+ios_base::failure::failure(const char* msg, const error_code& ec)
+    : system_error(ec, msg)
+{
+}
+
+ios_base::failure::~failure() throw()
+{
+}
+
+// ios_base locale
+
+const ios_base::fmtflags ios_base::boolalpha;
+const ios_base::fmtflags ios_base::dec;
+const ios_base::fmtflags ios_base::fixed;
+const ios_base::fmtflags ios_base::hex;
+const ios_base::fmtflags ios_base::internal;
+const ios_base::fmtflags ios_base::left;
+const ios_base::fmtflags ios_base::oct;
+const ios_base::fmtflags ios_base::right;
+const ios_base::fmtflags ios_base::scientific;
+const ios_base::fmtflags ios_base::showbase;
+const ios_base::fmtflags ios_base::showpoint;
+const ios_base::fmtflags ios_base::showpos;
+const ios_base::fmtflags ios_base::skipws;
+const ios_base::fmtflags ios_base::unitbuf;
+const ios_base::fmtflags ios_base::uppercase;
+const ios_base::fmtflags ios_base::adjustfield;
+const ios_base::fmtflags ios_base::basefield;
+const ios_base::fmtflags ios_base::floatfield;
+
+const ios_base::iostate ios_base::badbit;
+const ios_base::iostate ios_base::eofbit;
+const ios_base::iostate ios_base::failbit;
+const ios_base::iostate ios_base::goodbit;
+
+const ios_base::openmode ios_base::app;
+const ios_base::openmode ios_base::ate;
+const ios_base::openmode ios_base::binary;
+const ios_base::openmode ios_base::in;
+const ios_base::openmode ios_base::out;
+const ios_base::openmode ios_base::trunc;
+
+void
+ios_base::__call_callbacks(event ev)
+{
+    for (size_t i = __event_size_; i;)
+    {
+        --i;
+        __fn_[i](ev, *this, __index_[i]);
+    }
+}
+
+// locale
+
+locale
+ios_base::imbue(const locale& newloc)
+{
+    static_assert(sizeof(locale) == sizeof(__loc_), "");
+    locale& loc_storage = *reinterpret_cast<locale*>(&__loc_);
+    locale oldloc = loc_storage;
+    loc_storage = newloc;
+    __call_callbacks(imbue_event);
+    return oldloc;
+}
+
+locale
+ios_base::getloc() const
+{
+    const locale& loc_storage = *reinterpret_cast<const locale*>(&__loc_);
+    return loc_storage;
+}
+
+// xalloc
+#if defined(_LIBCPP_HAS_C_ATOMIC_IMP) && !defined(_LIBCPP_HAS_NO_THREADS)
+atomic<int> ios_base::__xindex_ = ATOMIC_VAR_INIT(0);
+#else
+int ios_base::__xindex_ = 0;
+#endif
+
+template <typename _Tp>
+static size_t __ios_new_cap(size_t __req_size, size_t __current_cap)
+{ // Precondition: __req_size > __current_cap
+	const size_t mx = std::numeric_limits<size_t>::max() / sizeof(_Tp);
+	if (__req_size < mx/2)
+		return _VSTD::max(2 * __current_cap, __req_size);
+	else
+		return mx;
+}
+
+int
+ios_base::xalloc()
+{
+    return __xindex_++;
+}
+
+long&
+ios_base::iword(int index)
+{
+    size_t req_size = static_cast<size_t>(index)+1;
+    if (req_size > __iarray_cap_)
+    {
+        size_t newcap = __ios_new_cap<long>(req_size, __iarray_cap_);
+        long* iarray = static_cast<long*>(realloc(__iarray_, newcap * sizeof(long)));
+        if (iarray == 0)
+        {
+            setstate(badbit);
+            static long error;
+            error = 0;
+            return error;
+        }
+        __iarray_ = iarray;
+        for (long* p = __iarray_ + __iarray_size_; p < __iarray_ + newcap; ++p)
+            *p = 0;
+        __iarray_cap_ = newcap;
+    }
+    __iarray_size_ = max<size_t>(__iarray_size_, req_size);
+    return __iarray_[index];
+}
+
+void*&
+ios_base::pword(int index)
+{
+    size_t req_size = static_cast<size_t>(index)+1;
+    if (req_size > __parray_cap_)
+    {
+        size_t newcap = __ios_new_cap<void *>(req_size, __iarray_cap_);
+        void** parray = static_cast<void**>(realloc(__parray_, newcap * sizeof(void *)));
+        if (parray == 0)
+        {
+            setstate(badbit);
+            static void* error;
+            error = 0;
+            return error;
+        }
+        __parray_ = parray;
+        for (void** p = __parray_ + __parray_size_; p < __parray_ + newcap; ++p)
+            *p = 0;
+        __parray_cap_ = newcap;
+    }
+    __parray_size_ = max<size_t>(__parray_size_, req_size);
+    return __parray_[index];
+}
+
+// register_callback
+
+void
+ios_base::register_callback(event_callback fn, int index)
+{
+    size_t req_size = __event_size_ + 1;
+    if (req_size > __event_cap_)
+    {
+        size_t newcap = __ios_new_cap<event_callback>(req_size, __event_cap_);
+        event_callback* fns = static_cast<event_callback*>(realloc(__fn_, newcap * sizeof(event_callback)));
+        if (fns == 0)
+            setstate(badbit);
+        __fn_ = fns;
+        int* indxs = static_cast<int *>(realloc(__index_, newcap * sizeof(int)));
+        if (indxs == 0)
+            setstate(badbit);
+        __index_ = indxs;
+        __event_cap_ = newcap;
+    }
+    __fn_[__event_size_] = fn;
+    __index_[__event_size_] = index;
+    ++__event_size_;
+}
+
+ios_base::~ios_base()
+{
+    __call_callbacks(erase_event);
+    locale& loc_storage = *reinterpret_cast<locale*>(&__loc_);
+    loc_storage.~locale();
+    free(__fn_);
+    free(__index_);
+    free(__iarray_);
+    free(__parray_);
+}
+
+// iostate
+
+void
+ios_base::clear(iostate state)
+{
+    if (__rdbuf_)
+        __rdstate_ = state;
+    else
+        __rdstate_ = state | badbit;
+
+    if (((state | (__rdbuf_ ? goodbit : badbit)) & __exceptions_) != 0)
+        __throw_failure("ios_base::clear");
+}
+
+// init
+
+void
+ios_base::init(void* sb)
+{
+    __rdbuf_ = sb;
+    __rdstate_ = __rdbuf_ ? goodbit : badbit;
+    __exceptions_ = goodbit;
+    __fmtflags_ = skipws | dec;
+    __width_ = 0;
+    __precision_ = 6;
+    __fn_ = 0;
+    __index_ = 0;
+    __event_size_ = 0;
+    __event_cap_ = 0;
+    __iarray_ = 0;
+    __iarray_size_ = 0;
+    __iarray_cap_ = 0;
+    __parray_ = 0;
+    __parray_size_ = 0;
+    __parray_cap_ = 0;
+    ::new(&__loc_) locale;
+}
+
+void
+ios_base::copyfmt(const ios_base& rhs)
+{
+    // If we can't acquire the needed resources, throw bad_alloc (can't set badbit)
+    // Don't alter *this until all needed resources are acquired
+    unique_ptr<event_callback, void (*)(void*)> new_callbacks(0, free);
+    unique_ptr<int, void (*)(void*)> new_ints(0, free);
+    unique_ptr<long, void (*)(void*)> new_longs(0, free);
+    unique_ptr<void*, void (*)(void*)> new_pointers(0, free);
+    if (__event_cap_ < rhs.__event_size_)
+    {
+        size_t newesize = sizeof(event_callback) * rhs.__event_size_;
+        new_callbacks.reset(static_cast<event_callback*>(malloc(newesize)));
+        if (!new_callbacks)
+            __throw_bad_alloc();
+
+        size_t newisize = sizeof(int) * rhs.__event_size_;
+        new_ints.reset(static_cast<int *>(malloc(newisize)));
+        if (!new_ints)
+            __throw_bad_alloc();
+    }
+    if (__iarray_cap_ < rhs.__iarray_size_)
+    {
+        size_t newsize = sizeof(long) * rhs.__iarray_size_;
+        new_longs.reset(static_cast<long*>(malloc(newsize)));
+        if (!new_longs)
+            __throw_bad_alloc();
+    }
+    if (__parray_cap_ < rhs.__parray_size_)
+    {
+        size_t newsize = sizeof(void*) * rhs.__parray_size_;
+        new_pointers.reset(static_cast<void**>(malloc(newsize)));
+        if (!new_pointers)
+            __throw_bad_alloc();
+    }
+    // Got everything we need.  Copy everything but __rdstate_, __rdbuf_ and __exceptions_
+    __fmtflags_ = rhs.__fmtflags_;
+    __precision_ = rhs.__precision_;
+    __width_ = rhs.__width_;
+    locale& lhs_loc = *reinterpret_cast<locale*>(&__loc_);
+    const locale& rhs_loc = *reinterpret_cast<const locale*>(&rhs.__loc_);
+    lhs_loc = rhs_loc;
+    if (__event_cap_ < rhs.__event_size_)
+    {
+        free(__fn_);
+        __fn_ = new_callbacks.release();
+        free(__index_);
+        __index_ = new_ints.release();
+        __event_cap_ = rhs.__event_size_;
+    }
+    for (__event_size_ = 0; __event_size_ < rhs.__event_size_; ++__event_size_)
+    {
+        __fn_[__event_size_] = rhs.__fn_[__event_size_];
+        __index_[__event_size_] = rhs.__index_[__event_size_];
+    }
+    if (__iarray_cap_ < rhs.__iarray_size_)
+    {
+        free(__iarray_);
+        __iarray_ = new_longs.release();
+        __iarray_cap_ = rhs.__iarray_size_;
+    }
+    for (__iarray_size_ = 0; __iarray_size_ < rhs.__iarray_size_; ++__iarray_size_)
+        __iarray_[__iarray_size_] = rhs.__iarray_[__iarray_size_];
+    if (__parray_cap_ < rhs.__parray_size_)
+    {
+        free(__parray_);
+        __parray_ = new_pointers.release();
+        __parray_cap_ = rhs.__parray_size_;
+    }
+    for (__parray_size_ = 0; __parray_size_ < rhs.__parray_size_; ++__parray_size_)
+        __parray_[__parray_size_] = rhs.__parray_[__parray_size_];
+}
+
+void
+ios_base::move(ios_base& rhs)
+{
+    // *this is uninitialized
+    __fmtflags_ = rhs.__fmtflags_;
+    __precision_ = rhs.__precision_;
+    __width_ = rhs.__width_;
+    __rdstate_ = rhs.__rdstate_;
+    __exceptions_ = rhs.__exceptions_;
+    __rdbuf_ = 0;
+    locale& rhs_loc = *reinterpret_cast<locale*>(&rhs.__loc_);
+    ::new(&__loc_) locale(rhs_loc);
+    __fn_ = rhs.__fn_;
+    rhs.__fn_ = 0;
+    __index_ = rhs.__index_;
+    rhs.__index_ = 0;
+    __event_size_ = rhs.__event_size_;
+    rhs.__event_size_ = 0;
+    __event_cap_ = rhs.__event_cap_;
+    rhs.__event_cap_ = 0;
+    __iarray_ = rhs.__iarray_;
+    rhs.__iarray_ = 0;
+    __iarray_size_ = rhs.__iarray_size_;
+    rhs.__iarray_size_ = 0;
+    __iarray_cap_ = rhs.__iarray_cap_;
+    rhs.__iarray_cap_ = 0;
+    __parray_ = rhs.__parray_;
+    rhs.__parray_ = 0;
+    __parray_size_ = rhs.__parray_size_;
+    rhs.__parray_size_ = 0;
+    __parray_cap_ = rhs.__parray_cap_;
+    rhs.__parray_cap_ = 0;
+}
+
+void
+ios_base::swap(ios_base& rhs) noexcept
+{
+    _VSTD::swap(__fmtflags_, rhs.__fmtflags_);
+    _VSTD::swap(__precision_, rhs.__precision_);
+    _VSTD::swap(__width_, rhs.__width_);
+    _VSTD::swap(__rdstate_, rhs.__rdstate_);
+    _VSTD::swap(__exceptions_, rhs.__exceptions_);
+    locale& lhs_loc = *reinterpret_cast<locale*>(&__loc_);
+    locale& rhs_loc = *reinterpret_cast<locale*>(&rhs.__loc_);
+    _VSTD::swap(lhs_loc, rhs_loc);
+    _VSTD::swap(__fn_, rhs.__fn_);
+    _VSTD::swap(__index_, rhs.__index_);
+    _VSTD::swap(__event_size_, rhs.__event_size_);
+    _VSTD::swap(__event_cap_, rhs.__event_cap_);
+    _VSTD::swap(__iarray_, rhs.__iarray_);
+    _VSTD::swap(__iarray_size_, rhs.__iarray_size_);
+    _VSTD::swap(__iarray_cap_, rhs.__iarray_cap_);
+    _VSTD::swap(__parray_, rhs.__parray_);
+    _VSTD::swap(__parray_size_, rhs.__parray_size_);
+    _VSTD::swap(__parray_cap_, rhs.__parray_cap_);
+}
+
+void
+ios_base::__set_badbit_and_consider_rethrow()
+{
+    __rdstate_ |= badbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    if (__exceptions_ & badbit)
+        throw;
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+void
+ios_base::__set_failbit_and_consider_rethrow()
+{
+    __rdstate_ |= failbit;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    if (__exceptions_ & failbit)
+        throw;
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+bool
+ios_base::sync_with_stdio(bool sync)
+{
+    static bool previous_state = true;
+    bool r = previous_state;
+    previous_state = sync;
+    return r;
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/ios.instantiations.cpp b/contrib/libs/cxxsupp/libcxx/src/ios.instantiations.cpp
new file mode 100644
index 00000000000..e1189d0b5bd
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/ios.instantiations.cpp
@@ -0,0 +1,46 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "__config"
+#include "fstream"
+#include "ios"
+#include "istream"
+#include "ostream"
+#include "sstream"
+#include "streambuf"
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Original explicit instantiations provided in the library
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_ios<char>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_streambuf<char>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_istream<char>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_ostream<char>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_iostream<char>;
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_ios<wchar_t>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_streambuf<wchar_t>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_istream<wchar_t>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_ostream<wchar_t>;
+#endif
+
+// Additional instantiations added later. Whether programs rely on these being
+// available is protected by _LIBCPP_ABI_ENABLE_ADDITIONAL_IOSTREAM_EXPLICIT_INSTANTIATIONS_1.
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_stringbuf<char>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_stringstream<char>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_ostringstream<char>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_istringstream<char>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_ifstream<char>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_ofstream<char>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_filebuf<char>;
+
+// Add more here if needed...
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/iostream.cpp b/contrib/libs/cxxsupp/libcxx/src/iostream.cpp
new file mode 100644
index 00000000000..5c1f5ed9eed
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/iostream.cpp
@@ -0,0 +1,211 @@
+//===------------------------ iostream.cpp --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "__std_stream"
+#include "__locale"
+#include "string"
+#include "new"
+
+#define _str(s) #s
+#define str(s) _str(s)
+#define _LIBCPP_ABI_NAMESPACE_STR str(_LIBCPP_ABI_NAMESPACE)
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if defined(_LIBCPP_ABI_MICROSOFT) && !defined(__clang__)
+_ALIGNAS_TYPE (istream) char _cin [sizeof(istream)];
+_LIBCPP_FUNC_VIS istream& cin = *reinterpret_cast<istream*>(_cin);
+#else
+_ALIGNAS_TYPE (istream) _LIBCPP_FUNC_VIS char cin[sizeof(istream)]
+#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
+__asm__("?cin@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_istream@DU?$char_traits@D@" _LIBCPP_ABI_NAMESPACE_STR "@std@@@12@A")
+#endif
+;
+#endif
+_ALIGNAS_TYPE (__stdinbuf<char> ) static char __cin[sizeof(__stdinbuf <char>)];
+static mbstate_t mb_cin;
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#if defined(_LIBCPP_ABI_MICROSOFT) && !defined(__clang__)
+_ALIGNAS_TYPE (wistream) char _wcin [sizeof(wistream)];
+_LIBCPP_FUNC_VIS wistream& wcin = *reinterpret_cast<wistream*>(_wcin);
+#else
+_ALIGNAS_TYPE (wistream) _LIBCPP_FUNC_VIS char wcin[sizeof(wistream)]
+#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
+__asm__("?wcin@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_istream@_WU?$char_traits@_W@" _LIBCPP_ABI_NAMESPACE_STR "@std@@@12@A")
+#endif
+;
+#endif
+_ALIGNAS_TYPE (__stdinbuf<wchar_t> ) static char __wcin[sizeof(__stdinbuf <wchar_t>)];
+static mbstate_t mb_wcin;
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+#if defined(_LIBCPP_ABI_MICROSOFT) && !defined(__clang__)
+_ALIGNAS_TYPE (ostream)  char _cout[sizeof(ostream)];
+_LIBCPP_FUNC_VIS ostream& cout = *reinterpret_cast<ostream*>(_cout);
+#else
+_ALIGNAS_TYPE (ostream) _LIBCPP_FUNC_VIS char cout[sizeof(ostream)]
+#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
+__asm__("?cout@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream@DU?$char_traits@D@" _LIBCPP_ABI_NAMESPACE_STR "@std@@@12@A")
+#endif
+;
+#endif
+_ALIGNAS_TYPE (__stdoutbuf<char>) static char __cout[sizeof(__stdoutbuf<char>)];
+static mbstate_t mb_cout;
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#if defined(_LIBCPP_ABI_MICROSOFT) && !defined(__clang__)
+_ALIGNAS_TYPE (wostream) char _wcout[sizeof(wostream)];
+_LIBCPP_FUNC_VIS wostream& wcout = *reinterpret_cast<wostream*>(_wcout);
+#else
+_ALIGNAS_TYPE (wostream) _LIBCPP_FUNC_VIS char wcout[sizeof(wostream)]
+#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
+__asm__("?wcout@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream@_WU?$char_traits@_W@" _LIBCPP_ABI_NAMESPACE_STR "@std@@@12@A")
+#endif
+;
+#endif
+_ALIGNAS_TYPE (__stdoutbuf<wchar_t>) static char __wcout[sizeof(__stdoutbuf<wchar_t>)];
+static mbstate_t mb_wcout;
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+#if defined(_LIBCPP_ABI_MICROSOFT) && !defined(__clang__)
+_ALIGNAS_TYPE (ostream)  char _cerr[sizeof(ostream)];
+_LIBCPP_FUNC_VIS ostream& cerr = *reinterpret_cast<ostream*>(_cerr);
+#else
+_ALIGNAS_TYPE (ostream) _LIBCPP_FUNC_VIS char cerr[sizeof(ostream)]
+#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
+__asm__("?cerr@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream@DU?$char_traits@D@" _LIBCPP_ABI_NAMESPACE_STR "@std@@@12@A")
+#endif
+;
+#endif
+_ALIGNAS_TYPE (__stdoutbuf<char>) static char __cerr[sizeof(__stdoutbuf<char>)];
+static mbstate_t mb_cerr;
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#if defined(_LIBCPP_ABI_MICROSOFT) && !defined(__clang__)
+_ALIGNAS_TYPE (wostream) char _wcerr[sizeof(wostream)];
+_LIBCPP_FUNC_VIS wostream& wcerr = *reinterpret_cast<wostream*>(_wcerr);
+#else
+_ALIGNAS_TYPE (wostream) _LIBCPP_FUNC_VIS char wcerr[sizeof(wostream)]
+#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
+__asm__("?wcerr@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream@_WU?$char_traits@_W@" _LIBCPP_ABI_NAMESPACE_STR "@std@@@12@A")
+#endif
+;
+#endif
+_ALIGNAS_TYPE (__stdoutbuf<wchar_t>) static char __wcerr[sizeof(__stdoutbuf<wchar_t>)];
+static mbstate_t mb_wcerr;
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+#if defined(_LIBCPP_ABI_MICROSOFT) && !defined(__clang__)
+_ALIGNAS_TYPE (ostream)  char _clog[sizeof(ostream)];
+_LIBCPP_FUNC_VIS ostream& clog = *reinterpret_cast<ostream*>(_clog);
+#else
+_ALIGNAS_TYPE (ostream) _LIBCPP_FUNC_VIS char clog[sizeof(ostream)]
+#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
+__asm__("?clog@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream@DU?$char_traits@D@" _LIBCPP_ABI_NAMESPACE_STR "@std@@@12@A")
+#endif
+;
+#endif
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#if defined(_LIBCPP_ABI_MICROSOFT) && !defined(__clang__)
+_ALIGNAS_TYPE (wostream) char _wclog[sizeof(wostream)];
+_LIBCPP_FUNC_VIS wostream& wclog = *reinterpret_cast<wostream*>(_wclog);
+#else
+_ALIGNAS_TYPE (wostream) _LIBCPP_FUNC_VIS char wclog[sizeof(wostream)]
+#if defined(_LIBCPP_ABI_MICROSOFT) && defined(__clang__)
+__asm__("?wclog@" _LIBCPP_ABI_NAMESPACE_STR "@std@@3V?$basic_ostream@_WU?$char_traits@_W@" _LIBCPP_ABI_NAMESPACE_STR "@std@@@12@A")
+#endif
+;
+#endif
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// Hacky way to make the compiler believe that we're inside a system header so
+// it doesn't flag the use of the init_priority attribute with a value that's
+// reserved for the implementation (we're the implementation).
+#ifndef _LIBCPP_COMPILER_MSVC
+# 80 "iostream.cpp" 1 3
+#endif
+_LIBCPP_HIDDEN ios_base::Init __start_std_streams _LIBCPP_INIT_PRIORITY_MAX;
+#ifndef _LIBCPP_COMPILER_MSVC
+# 82 "iostream.cpp" 2
+#endif
+
+// On Windows the TLS storage for locales needs to be initialized before we create
+// the standard streams, otherwise it may not be alive during program termination
+// when we flush the streams.
+static void force_locale_initialization() {
+#if defined(_LIBCPP_MSVCRT_LIKE)
+  static bool once = []() {
+    auto loc = newlocale(LC_ALL_MASK, "C", 0);
+    {
+        __libcpp_locale_guard g(loc); // forces initialization of locale TLS
+        ((void)g);
+    }
+    freelocale(loc);
+    return true;
+  }();
+  ((void)once);
+#endif
+}
+
+class DoIOSInit {
+public:
+	DoIOSInit();
+	~DoIOSInit();
+};
+
+DoIOSInit::DoIOSInit()
+{
+    force_locale_initialization();
+
+    istream* cin_ptr  = ::new(&cin)  istream(::new(__cin)  __stdinbuf <char>(stdin, &mb_cin));
+    ostream* cout_ptr = ::new(&cout) ostream(::new(__cout) __stdoutbuf<char>(stdout, &mb_cout));
+    ostream* cerr_ptr = ::new(&cerr) ostream(::new(__cerr) __stdoutbuf<char>(stderr, &mb_cerr));
+                        ::new(&clog) ostream(cerr_ptr->rdbuf());
+    cin_ptr->tie(cout_ptr);
+    _VSTD::unitbuf(*cerr_ptr);
+    cerr_ptr->tie(cout_ptr);
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    wistream* wcin_ptr  = ::new(&wcin)  wistream(::new(__wcin)  __stdinbuf <wchar_t>(stdin, &mb_wcin));
+    wostream* wcout_ptr = ::new(&wcout) wostream(::new(__wcout) __stdoutbuf<wchar_t>(stdout, &mb_wcout));
+    wostream* wcerr_ptr = ::new(&wcerr) wostream(::new(__wcerr) __stdoutbuf<wchar_t>(stderr, &mb_wcerr));
+                          ::new(&wclog) wostream(wcerr_ptr->rdbuf());
+
+    wcin_ptr->tie(wcout_ptr);
+    _VSTD::unitbuf(*wcerr_ptr);
+    wcerr_ptr->tie(wcout_ptr);
+#endif
+}
+
+DoIOSInit::~DoIOSInit()
+{
+    ostream* cout_ptr = reinterpret_cast<ostream*>(&cout);
+    cout_ptr->flush();
+    ostream* clog_ptr = reinterpret_cast<ostream*>(&clog);
+    clog_ptr->flush();
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    wostream* wcout_ptr = reinterpret_cast<wostream*>(&wcout);
+    wcout_ptr->flush();
+    wostream* wclog_ptr = reinterpret_cast<wostream*>(&wclog);
+    wclog_ptr->flush();
+#endif
+}
+
+ios_base::Init::Init()
+{
+    static DoIOSInit init_the_streams; // gets initialized once
+}
+
+ios_base::Init::~Init()
+{
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/locale.cpp b/contrib/libs/cxxsupp/libcxx/src/locale.cpp
new file mode 100644
index 00000000000..42b5641b43a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/locale.cpp
@@ -0,0 +1,6573 @@
+//===------------------------- locale.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// On Solaris, we need to define something to make the C99 parts of localeconv
+// visible.
+#ifdef __sun__
+#define _LCONV_C99
+#endif
+
+#include "clocale"
+#include "codecvt"
+#include "cstdio"
+#include "cstdlib"
+#include "cstring"
+#include "locale"
+#include "string"
+#include "type_traits"
+#include "typeinfo"
+#include "vector"
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#   include "cwctype"
+#endif
+
+#if defined(_AIX)
+#   include <sys/localedef.h> // for __lc_ctype_ptr
+#endif
+
+#if defined(_LIBCPP_MSVCRT)
+#    define _CTYPE_DISABLE_MACROS
+#endif
+#if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
+#    include "__support/win32/locale_win32.h"
+#elif !defined(__BIONIC__) && !defined(__NuttX__)
+#    include <langinfo.h>
+#endif
+
+#include "atomic"
+#include "include/sso_allocator.h"
+#include "__undef_macros"
+
+// On Linux, wint_t and wchar_t have different signed-ness, and this causes
+// lots of noise in the build log, but no bugs that I know of.
+#if defined(__clang__)
+#pragma clang diagnostic ignored "-Wsign-conversion"
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+struct __libcpp_unique_locale {
+  __libcpp_unique_locale(const char* nm) : __loc_(newlocale(LC_ALL_MASK, nm, 0)) {}
+
+  ~__libcpp_unique_locale() {
+    if (__loc_)
+      freelocale(__loc_);
+  }
+
+  explicit operator bool() const { return __loc_; }
+
+  locale_t& get() { return __loc_; }
+
+  locale_t __loc_;
+private:
+  __libcpp_unique_locale(__libcpp_unique_locale const&);
+  __libcpp_unique_locale& operator=(__libcpp_unique_locale const&);
+};
+
+#ifdef __cloc_defined
+locale_t __cloc() {
+  // In theory this could create a race condition. In practice
+  // the race condition is non-fatal since it will just create
+  // a little resource leak. Better approach would be appreciated.
+  static locale_t result = newlocale(LC_ALL_MASK, "C", 0);
+  return result;
+}
+#endif // __cloc_defined
+
+namespace {
+
+struct release
+{
+    void operator()(locale::facet* p) {p->__release_shared();}
+};
+
+template <class T, class ...Args>
+T& make(Args ...args)
+{
+    static typename aligned_storage<sizeof(T)>::type buf;
+    auto *obj = ::new (&buf) T(args...);
+    return *obj;
+}
+
+template <typename T, size_t N>
+inline
+_LIBCPP_CONSTEXPR
+size_t
+countof(const T (&)[N])
+{
+    return N;
+}
+
+template <typename T>
+inline
+_LIBCPP_CONSTEXPR
+size_t
+countof(const T * const begin, const T * const end)
+{
+    return static_cast<size_t>(end - begin);
+}
+
+_LIBCPP_NORETURN static void __throw_runtime_error(const string &msg)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw runtime_error(msg);
+#else
+    (void)msg;
+    _VSTD::abort();
+#endif
+}
+
+}
+
+#if defined(_AIX)
+// Set priority to INT_MIN + 256 + 150
+# pragma priority ( -2147483242 )
+#endif
+
+const locale::category locale::none;
+const locale::category locale::collate;
+const locale::category locale::ctype;
+const locale::category locale::monetary;
+const locale::category locale::numeric;
+const locale::category locale::time;
+const locale::category locale::messages;
+const locale::category locale::all;
+
+class _LIBCPP_HIDDEN locale::__imp
+    : public facet
+{
+    enum {N = 30};
+    vector<facet*, __sso_allocator<facet*, N> > facets_;
+    string         name_;
+public:
+    explicit __imp(size_t refs = 0);
+    explicit __imp(const string& name, size_t refs = 0);
+    __imp(const __imp&);
+    __imp(const __imp&, const string&, locale::category c);
+    __imp(const __imp& other, const __imp& one, locale::category c);
+    __imp(const __imp&, facet* f, long id);
+    ~__imp();
+
+    const string& name() const {return name_;}
+    bool has_facet(long id) const
+        {return static_cast<size_t>(id) < facets_.size() && facets_[static_cast<size_t>(id)];}
+    const locale::facet* use_facet(long id) const;
+
+    static const locale& make_classic();
+    static       locale& make_global();
+private:
+    void install(facet* f, long id);
+    template <class F> void install(F* f) {install(f, f->id.__get());}
+    template <class F> void install_from(const __imp& other);
+};
+
+locale::__imp::__imp(size_t refs)
+    : facet(refs),
+      facets_(N),
+      name_("C")
+{
+    facets_.clear();
+    install(&make<_VSTD::collate<char> >(1u));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    install(&make<_VSTD::collate<wchar_t> >(1u));
+#endif
+    install(&make<_VSTD::ctype<char> >(nullptr, false, 1u));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    install(&make<_VSTD::ctype<wchar_t> >(1u));
+#endif
+    install(&make<codecvt<char, char, mbstate_t> >(1u));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    install(&make<codecvt<wchar_t, char, mbstate_t> >(1u));
+#endif
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+    install(&make<codecvt<char16_t, char, mbstate_t> >(1u));
+    install(&make<codecvt<char32_t, char, mbstate_t> >(1u));
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+    install(&make<codecvt<char16_t, char8_t, mbstate_t> >(1u));
+    install(&make<codecvt<char32_t, char8_t, mbstate_t> >(1u));
+#endif
+    install(&make<numpunct<char> >(1u));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    install(&make<numpunct<wchar_t> >(1u));
+#endif
+    install(&make<num_get<char> >(1u));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    install(&make<num_get<wchar_t> >(1u));
+#endif
+    install(&make<num_put<char> >(1u));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    install(&make<num_put<wchar_t> >(1u));
+#endif
+    install(&make<moneypunct<char, false> >(1u));
+    install(&make<moneypunct<char, true> >(1u));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    install(&make<moneypunct<wchar_t, false> >(1u));
+    install(&make<moneypunct<wchar_t, true> >(1u));
+#endif
+    install(&make<money_get<char> >(1u));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    install(&make<money_get<wchar_t> >(1u));
+#endif
+    install(&make<money_put<char> >(1u));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    install(&make<money_put<wchar_t> >(1u));
+#endif
+    install(&make<time_get<char> >(1u));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    install(&make<time_get<wchar_t> >(1u));
+#endif
+    install(&make<time_put<char> >(1u));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    install(&make<time_put<wchar_t> >(1u));
+#endif
+    install(&make<_VSTD::messages<char> >(1u));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    install(&make<_VSTD::messages<wchar_t> >(1u));
+#endif
+}
+
+locale::__imp::__imp(const string& name, size_t refs)
+    : facet(refs),
+      facets_(N),
+      name_(name)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        facets_ = locale::classic().__locale_->facets_;
+        for (unsigned i = 0; i < facets_.size(); ++i)
+            if (facets_[i])
+                facets_[i]->__add_shared();
+        install(new collate_byname<char>(name_));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        install(new collate_byname<wchar_t>(name_));
+#endif
+        install(new ctype_byname<char>(name_));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        install(new ctype_byname<wchar_t>(name_));
+#endif
+        install(new codecvt_byname<char, char, mbstate_t>(name_));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        install(new codecvt_byname<wchar_t, char, mbstate_t>(name_));
+#endif
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+        install(new codecvt_byname<char16_t, char, mbstate_t>(name_));
+        install(new codecvt_byname<char32_t, char, mbstate_t>(name_));
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+        install(new codecvt_byname<char16_t, char8_t, mbstate_t>(name_));
+        install(new codecvt_byname<char32_t, char8_t, mbstate_t>(name_));
+#endif
+        install(new numpunct_byname<char>(name_));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        install(new numpunct_byname<wchar_t>(name_));
+#endif
+        install(new moneypunct_byname<char, false>(name_));
+        install(new moneypunct_byname<char, true>(name_));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        install(new moneypunct_byname<wchar_t, false>(name_));
+        install(new moneypunct_byname<wchar_t, true>(name_));
+#endif
+        install(new time_get_byname<char>(name_));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        install(new time_get_byname<wchar_t>(name_));
+#endif
+        install(new time_put_byname<char>(name_));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        install(new time_put_byname<wchar_t>(name_));
+#endif
+        install(new messages_byname<char>(name_));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        install(new messages_byname<wchar_t>(name_));
+#endif
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        for (unsigned i = 0; i < facets_.size(); ++i)
+            if (facets_[i])
+                facets_[i]->__release_shared();
+        throw;
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+locale::__imp::__imp(const __imp& other)
+    : facets_(max<size_t>(N, other.facets_.size())),
+      name_(other.name_)
+{
+    facets_ = other.facets_;
+    for (unsigned i = 0; i < facets_.size(); ++i)
+        if (facets_[i])
+            facets_[i]->__add_shared();
+}
+
+locale::__imp::__imp(const __imp& other, const string& name, locale::category c)
+    : facets_(N),
+      name_("*")
+{
+    facets_ = other.facets_;
+    for (unsigned i = 0; i < facets_.size(); ++i)
+        if (facets_[i])
+            facets_[i]->__add_shared();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        if (c & locale::collate)
+        {
+            install(new collate_byname<char>(name));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install(new collate_byname<wchar_t>(name));
+#endif
+        }
+        if (c & locale::ctype)
+        {
+            install(new ctype_byname<char>(name));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install(new ctype_byname<wchar_t>(name));
+#endif
+            install(new codecvt_byname<char, char, mbstate_t>(name));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install(new codecvt_byname<wchar_t, char, mbstate_t>(name));
+#endif
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+            install(new codecvt_byname<char16_t, char, mbstate_t>(name));
+            install(new codecvt_byname<char32_t, char, mbstate_t>(name));
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+            install(new codecvt_byname<char16_t, char8_t, mbstate_t>(name));
+            install(new codecvt_byname<char32_t, char8_t, mbstate_t>(name));
+#endif
+        }
+        if (c & locale::monetary)
+        {
+            install(new moneypunct_byname<char, false>(name));
+            install(new moneypunct_byname<char, true>(name));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install(new moneypunct_byname<wchar_t, false>(name));
+            install(new moneypunct_byname<wchar_t, true>(name));
+#endif
+        }
+        if (c & locale::numeric)
+        {
+            install(new numpunct_byname<char>(name));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install(new numpunct_byname<wchar_t>(name));
+#endif
+        }
+        if (c & locale::time)
+        {
+            install(new time_get_byname<char>(name));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install(new time_get_byname<wchar_t>(name));
+#endif
+            install(new time_put_byname<char>(name));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install(new time_put_byname<wchar_t>(name));
+#endif
+        }
+        if (c & locale::messages)
+        {
+            install(new messages_byname<char>(name));
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install(new messages_byname<wchar_t>(name));
+#endif
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        for (unsigned i = 0; i < facets_.size(); ++i)
+            if (facets_[i])
+                facets_[i]->__release_shared();
+        throw;
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+template<class F>
+inline
+void
+locale::__imp::install_from(const locale::__imp& one)
+{
+    long id = F::id.__get();
+    install(const_cast<F*>(static_cast<const F*>(one.use_facet(id))), id);
+}
+
+locale::__imp::__imp(const __imp& other, const __imp& one, locale::category c)
+    : facets_(N),
+      name_("*")
+{
+    facets_ = other.facets_;
+    for (unsigned i = 0; i < facets_.size(); ++i)
+        if (facets_[i])
+            facets_[i]->__add_shared();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        if (c & locale::collate)
+        {
+            install_from<_VSTD::collate<char> >(one);
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install_from<_VSTD::collate<wchar_t> >(one);
+#endif
+        }
+        if (c & locale::ctype)
+        {
+            install_from<_VSTD::ctype<char> >(one);
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install_from<_VSTD::ctype<wchar_t> >(one);
+#endif
+            install_from<_VSTD::codecvt<char, char, mbstate_t> >(one);
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+            install_from<_VSTD::codecvt<char16_t, char, mbstate_t> >(one);
+            install_from<_VSTD::codecvt<char32_t, char, mbstate_t> >(one);
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+            install_from<_VSTD::codecvt<char16_t, char8_t, mbstate_t> >(one);
+            install_from<_VSTD::codecvt<char32_t, char8_t, mbstate_t> >(one);
+#endif
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install_from<_VSTD::codecvt<wchar_t, char, mbstate_t> >(one);
+#endif
+        }
+        if (c & locale::monetary)
+        {
+            install_from<moneypunct<char, false> >(one);
+            install_from<moneypunct<char, true> >(one);
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install_from<moneypunct<wchar_t, false> >(one);
+            install_from<moneypunct<wchar_t, true> >(one);
+#endif
+            install_from<money_get<char> >(one);
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install_from<money_get<wchar_t> >(one);
+#endif
+            install_from<money_put<char> >(one);
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install_from<money_put<wchar_t> >(one);
+#endif
+        }
+        if (c & locale::numeric)
+        {
+            install_from<numpunct<char> >(one);
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install_from<numpunct<wchar_t> >(one);
+#endif
+            install_from<num_get<char> >(one);
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install_from<num_get<wchar_t> >(one);
+#endif
+            install_from<num_put<char> >(one);
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install_from<num_put<wchar_t> >(one);
+#endif
+        }
+        if (c & locale::time)
+        {
+            install_from<time_get<char> >(one);
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install_from<time_get<wchar_t> >(one);
+#endif
+            install_from<time_put<char> >(one);
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install_from<time_put<wchar_t> >(one);
+#endif
+        }
+        if (c & locale::messages)
+        {
+            install_from<_VSTD::messages<char> >(one);
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+            install_from<_VSTD::messages<wchar_t> >(one);
+#endif
+        }
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        for (unsigned i = 0; i < facets_.size(); ++i)
+            if (facets_[i])
+                facets_[i]->__release_shared();
+        throw;
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+locale::__imp::__imp(const __imp& other, facet* f, long id)
+    : facets_(max<size_t>(N, other.facets_.size()+1)),
+      name_("*")
+{
+    f->__add_shared();
+    unique_ptr<facet, release> hold(f);
+    facets_ = other.facets_;
+    for (unsigned i = 0; i < other.facets_.size(); ++i)
+        if (facets_[i])
+            facets_[i]->__add_shared();
+    install(hold.get(), id);
+}
+
+locale::__imp::~__imp()
+{
+    for (unsigned i = 0; i < facets_.size(); ++i)
+        if (facets_[i])
+            facets_[i]->__release_shared();
+}
+
+void
+locale::__imp::install(facet* f, long id)
+{
+    f->__add_shared();
+    unique_ptr<facet, release> hold(f);
+    if (static_cast<size_t>(id) >= facets_.size())
+        facets_.resize(static_cast<size_t>(id+1));
+    if (facets_[static_cast<size_t>(id)])
+        facets_[static_cast<size_t>(id)]->__release_shared();
+    facets_[static_cast<size_t>(id)] = hold.release();
+}
+
+const locale::facet*
+locale::__imp::use_facet(long id) const
+{
+    if (!has_facet(id))
+        __throw_bad_cast();
+    return facets_[static_cast<size_t>(id)];
+}
+
+// locale
+
+const locale&
+locale::__imp::make_classic()
+{
+    // only one thread can get in here and it only gets in once
+    static aligned_storage<sizeof(locale)>::type buf;
+    locale* c = reinterpret_cast<locale*>(&buf);
+    c->__locale_ = &make<__imp>(1u);
+    return *c;
+}
+
+const locale&
+locale::classic()
+{
+    static const locale& c = __imp::make_classic();
+    return c;
+}
+
+locale&
+locale::__imp::make_global()
+{
+    // only one thread can get in here and it only gets in once
+    static aligned_storage<sizeof(locale)>::type buf;
+    auto *obj = ::new (&buf) locale(locale::classic());
+    return *obj;
+}
+
+locale&
+locale::__global()
+{
+    static locale& g = __imp::make_global();
+    return g;
+}
+
+locale::locale() noexcept
+    : __locale_(__global().__locale_)
+{
+    __locale_->__add_shared();
+}
+
+locale::locale(const locale& l) noexcept
+    : __locale_(l.__locale_)
+{
+    __locale_->__add_shared();
+}
+
+locale::~locale()
+{
+    __locale_->__release_shared();
+}
+
+const locale&
+locale::operator=(const locale& other) noexcept
+{
+    other.__locale_->__add_shared();
+    __locale_->__release_shared();
+    __locale_ = other.__locale_;
+    return *this;
+}
+
+locale::locale(const char* name)
+    : __locale_(name ? new __imp(name)
+                     : (__throw_runtime_error("locale constructed with null"), nullptr))
+{
+    __locale_->__add_shared();
+}
+
+locale::locale(const string& name)
+    : __locale_(new __imp(name))
+{
+    __locale_->__add_shared();
+}
+
+locale::locale(const locale& other, const char* name, category c)
+    : __locale_(name ? new __imp(*other.__locale_, name, c)
+                     : (__throw_runtime_error("locale constructed with null"), nullptr))
+{
+    __locale_->__add_shared();
+}
+
+locale::locale(const locale& other, const string& name, category c)
+    : __locale_(new __imp(*other.__locale_, name, c))
+{
+    __locale_->__add_shared();
+}
+
+locale::locale(const locale& other, const locale& one, category c)
+    : __locale_(new __imp(*other.__locale_, *one.__locale_, c))
+{
+    __locale_->__add_shared();
+}
+
+string
+locale::name() const
+{
+    return __locale_->name();
+}
+
+void
+locale::__install_ctor(const locale& other, facet* f, long id)
+{
+    if (f)
+        __locale_ = new __imp(*other.__locale_, f, id);
+    else
+        __locale_ = other.__locale_;
+    __locale_->__add_shared();
+}
+
+locale
+locale::global(const locale& loc)
+{
+    locale& g = __global();
+    locale r = g;
+    g = loc;
+    if (g.name() != "*")
+        setlocale(LC_ALL, g.name().c_str());
+    return r;
+}
+
+bool
+locale::has_facet(id& x) const
+{
+    return __locale_->has_facet(x.__get());
+}
+
+const locale::facet*
+locale::use_facet(id& x) const
+{
+    return __locale_->use_facet(x.__get());
+}
+
+bool
+locale::operator==(const locale& y) const
+{
+    return (__locale_ == y.__locale_)
+        || (__locale_->name() != "*" && __locale_->name() == y.__locale_->name());
+}
+
+// locale::facet
+
+locale::facet::~facet()
+{
+}
+
+void
+locale::facet::__on_zero_shared() noexcept
+{
+    delete this;
+}
+
+// locale::id
+
+namespace
+{
+
+class __fake_bind
+{
+    locale::id* id_;
+    void (locale::id::* pmf_)();
+public:
+    __fake_bind(void (locale::id::* pmf)(), locale::id* id)
+        : id_(id), pmf_(pmf) {}
+
+    void operator()() const
+    {
+        (id_->*pmf_)();
+    }
+};
+
+}
+
+int32_t locale::id::__next_id;
+
+long
+locale::id::__get()
+{
+    int32_t result = __id_.load(std::memory_order_acquire);
+    if (result == 0) {
+        static std::mutex m;
+        std::lock_guard<std::mutex> guard(m);
+        result = __id_.load(std::memory_order_acquire);
+        if (result == 0) {
+            result = ++__next_id;
+            __id_.store(result, std::memory_order_release);
+        }
+    }
+    return result - 1;
+}
+
+// template <> class collate_byname<char>
+
+collate_byname<char>::collate_byname(const char* n, size_t refs)
+    : collate<char>(refs),
+      __l(newlocale(LC_ALL_MASK, n, 0))
+{
+    if (__l == 0)
+        __throw_runtime_error("collate_byname<char>::collate_byname"
+                            " failed to construct for " + string(n));
+}
+
+collate_byname<char>::collate_byname(const string& name, size_t refs)
+    : collate<char>(refs),
+      __l(newlocale(LC_ALL_MASK, name.c_str(), 0))
+{
+    if (__l == 0)
+        __throw_runtime_error("collate_byname<char>::collate_byname"
+                            " failed to construct for " + name);
+}
+
+collate_byname<char>::~collate_byname()
+{
+    freelocale(__l);
+}
+
+int
+collate_byname<char>::do_compare(const char_type* __lo1, const char_type* __hi1,
+                                 const char_type* __lo2, const char_type* __hi2) const
+{
+    string_type lhs(__lo1, __hi1);
+    string_type rhs(__lo2, __hi2);
+    int r = strcoll_l(lhs.c_str(), rhs.c_str(), __l);
+    if (r < 0)
+        return -1;
+    if (r > 0)
+        return 1;
+    return r;
+}
+
+collate_byname<char>::string_type
+collate_byname<char>::do_transform(const char_type* lo, const char_type* hi) const
+{
+    const string_type in(lo, hi);
+    string_type out(strxfrm_l(0, in.c_str(), 0, __l), char());
+    strxfrm_l(const_cast<char*>(out.c_str()), in.c_str(), out.size()+1, __l);
+    return out;
+}
+
+// template <> class collate_byname<wchar_t>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+collate_byname<wchar_t>::collate_byname(const char* n, size_t refs)
+    : collate<wchar_t>(refs),
+      __l(newlocale(LC_ALL_MASK, n, 0))
+{
+    if (__l == 0)
+        __throw_runtime_error("collate_byname<wchar_t>::collate_byname(size_t refs)"
+                            " failed to construct for " + string(n));
+}
+
+collate_byname<wchar_t>::collate_byname(const string& name, size_t refs)
+    : collate<wchar_t>(refs),
+      __l(newlocale(LC_ALL_MASK, name.c_str(), 0))
+{
+    if (__l == 0)
+        __throw_runtime_error("collate_byname<wchar_t>::collate_byname(size_t refs)"
+                            " failed to construct for " + name);
+}
+
+collate_byname<wchar_t>::~collate_byname()
+{
+    freelocale(__l);
+}
+
+int
+collate_byname<wchar_t>::do_compare(const char_type* __lo1, const char_type* __hi1,
+                                 const char_type* __lo2, const char_type* __hi2) const
+{
+    string_type lhs(__lo1, __hi1);
+    string_type rhs(__lo2, __hi2);
+    int r = wcscoll_l(lhs.c_str(), rhs.c_str(), __l);
+    if (r < 0)
+        return -1;
+    if (r > 0)
+        return 1;
+    return r;
+}
+
+collate_byname<wchar_t>::string_type
+collate_byname<wchar_t>::do_transform(const char_type* lo, const char_type* hi) const
+{
+    const string_type in(lo, hi);
+    string_type out(wcsxfrm_l(0, in.c_str(), 0, __l), wchar_t());
+    wcsxfrm_l(const_cast<wchar_t*>(out.c_str()), in.c_str(), out.size()+1, __l);
+    return out;
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+const ctype_base::mask ctype_base::space;
+const ctype_base::mask ctype_base::print;
+const ctype_base::mask ctype_base::cntrl;
+const ctype_base::mask ctype_base::upper;
+const ctype_base::mask ctype_base::lower;
+const ctype_base::mask ctype_base::alpha;
+const ctype_base::mask ctype_base::digit;
+const ctype_base::mask ctype_base::punct;
+const ctype_base::mask ctype_base::xdigit;
+const ctype_base::mask ctype_base::blank;
+const ctype_base::mask ctype_base::alnum;
+const ctype_base::mask ctype_base::graph;
+
+// template <> class ctype<wchar_t>;
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+locale::id ctype<wchar_t>::id;
+
+ctype<wchar_t>::~ctype()
+{
+}
+
+bool
+ctype<wchar_t>::do_is(mask m, char_type c) const
+{
+    return isascii(c) ? (ctype<char>::classic_table()[c] & m) != 0 : false;
+}
+
+const wchar_t*
+ctype<wchar_t>::do_is(const char_type* low, const char_type* high, mask* vec) const
+{
+    for (; low != high; ++low, ++vec)
+        *vec = static_cast<mask>(isascii(*low) ?
+                                   ctype<char>::classic_table()[*low] : 0);
+    return low;
+}
+
+const wchar_t*
+ctype<wchar_t>::do_scan_is(mask m, const char_type* low, const char_type* high) const
+{
+    for (; low != high; ++low)
+        if (isascii(*low) && (ctype<char>::classic_table()[*low] & m))
+            break;
+    return low;
+}
+
+const wchar_t*
+ctype<wchar_t>::do_scan_not(mask m, const char_type* low, const char_type* high) const
+{
+    for (; low != high; ++low)
+        if (!(isascii(*low) && (ctype<char>::classic_table()[*low] & m)))
+            break;
+    return low;
+}
+
+wchar_t
+ctype<wchar_t>::do_toupper(char_type c) const
+{
+#ifdef _LIBCPP_HAS_DEFAULTRUNELOCALE
+    return isascii(c) ? _DefaultRuneLocale.__mapupper[c] : c;
+#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__) || \
+      defined(__NetBSD__)
+    return isascii(c) ? ctype<char>::__classic_upper_table()[c] : c;
+#else
+    return (isascii(c) && iswlower_l(c, _LIBCPP_GET_C_LOCALE)) ? c-L'a'+L'A' : c;
+#endif
+}
+
+const wchar_t*
+ctype<wchar_t>::do_toupper(char_type* low, const char_type* high) const
+{
+    for (; low != high; ++low)
+#ifdef _LIBCPP_HAS_DEFAULTRUNELOCALE
+        *low = isascii(*low) ? _DefaultRuneLocale.__mapupper[*low] : *low;
+#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__) || \
+      defined(__NetBSD__)
+        *low = isascii(*low) ? ctype<char>::__classic_upper_table()[*low]
+                             : *low;
+#else
+        *low = (isascii(*low) && islower_l(*low, _LIBCPP_GET_C_LOCALE)) ? (*low-L'a'+L'A') : *low;
+#endif
+    return low;
+}
+
+wchar_t
+ctype<wchar_t>::do_tolower(char_type c) const
+{
+#ifdef _LIBCPP_HAS_DEFAULTRUNELOCALE
+    return isascii(c) ? _DefaultRuneLocale.__maplower[c] : c;
+#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__) || \
+      defined(__NetBSD__)
+    return isascii(c) ? ctype<char>::__classic_lower_table()[c] : c;
+#else
+    return (isascii(c) && isupper_l(c, _LIBCPP_GET_C_LOCALE)) ? c-L'A'+'a' : c;
+#endif
+}
+
+const wchar_t*
+ctype<wchar_t>::do_tolower(char_type* low, const char_type* high) const
+{
+    for (; low != high; ++low)
+#ifdef _LIBCPP_HAS_DEFAULTRUNELOCALE
+        *low = isascii(*low) ? _DefaultRuneLocale.__maplower[*low] : *low;
+#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__) || \
+      defined(__NetBSD__)
+        *low = isascii(*low) ? ctype<char>::__classic_lower_table()[*low]
+                             : *low;
+#else
+        *low = (isascii(*low) && isupper_l(*low, _LIBCPP_GET_C_LOCALE)) ? *low-L'A'+L'a' : *low;
+#endif
+    return low;
+}
+
+wchar_t
+ctype<wchar_t>::do_widen(char c) const
+{
+    return c;
+}
+
+const char*
+ctype<wchar_t>::do_widen(const char* low, const char* high, char_type* dest) const
+{
+    for (; low != high; ++low, ++dest)
+        *dest = *low;
+    return low;
+}
+
+char
+ctype<wchar_t>::do_narrow(char_type c, char dfault) const
+{
+    if (isascii(c))
+        return static_cast<char>(c);
+    return dfault;
+}
+
+const wchar_t*
+ctype<wchar_t>::do_narrow(const char_type* low, const char_type* high, char dfault, char* dest) const
+{
+    for (; low != high; ++low, ++dest)
+        if (isascii(*low))
+            *dest = static_cast<char>(*low);
+        else
+            *dest = dfault;
+    return low;
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// template <> class ctype<char>;
+
+locale::id ctype<char>::id;
+
+ctype<char>::ctype(const mask* tab, bool del, size_t refs)
+    : locale::facet(refs),
+      __tab_(tab),
+      __del_(del)
+{
+  if (__tab_ == 0)
+      __tab_ = classic_table();
+}
+
+ctype<char>::~ctype()
+{
+    if (__tab_ && __del_)
+        delete [] __tab_;
+}
+
+char
+ctype<char>::do_toupper(char_type c) const
+{
+#ifdef _LIBCPP_HAS_DEFAULTRUNELOCALE
+    return isascii(c) ?
+      static_cast<char>(_DefaultRuneLocale.__mapupper[static_cast<ptrdiff_t>(c)]) : c;
+#elif defined(__NetBSD__)
+    return static_cast<char>(__classic_upper_table()[static_cast<unsigned char>(c)]);
+#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__)
+    return isascii(c) ?
+      static_cast<char>(__classic_upper_table()[static_cast<unsigned char>(c)]) : c;
+#else
+    return (isascii(c) && islower_l(c, _LIBCPP_GET_C_LOCALE)) ? c-'a'+'A' : c;
+#endif
+}
+
+const char*
+ctype<char>::do_toupper(char_type* low, const char_type* high) const
+{
+    for (; low != high; ++low)
+#ifdef _LIBCPP_HAS_DEFAULTRUNELOCALE
+        *low = isascii(*low) ?
+          static_cast<char>(_DefaultRuneLocale.__mapupper[static_cast<ptrdiff_t>(*low)]) : *low;
+#elif defined(__NetBSD__)
+        *low = static_cast<char>(__classic_upper_table()[static_cast<unsigned char>(*low)]);
+#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__)
+        *low = isascii(*low) ?
+          static_cast<char>(__classic_upper_table()[static_cast<size_t>(*low)]) : *low;
+#else
+        *low = (isascii(*low) && islower_l(*low, _LIBCPP_GET_C_LOCALE)) ? *low-'a'+'A' : *low;
+#endif
+    return low;
+}
+
+char
+ctype<char>::do_tolower(char_type c) const
+{
+#ifdef _LIBCPP_HAS_DEFAULTRUNELOCALE
+    return isascii(c) ?
+      static_cast<char>(_DefaultRuneLocale.__maplower[static_cast<ptrdiff_t>(c)]) : c;
+#elif defined(__NetBSD__)
+    return static_cast<char>(__classic_lower_table()[static_cast<unsigned char>(c)]);
+#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__)
+    return isascii(c) ?
+      static_cast<char>(__classic_lower_table()[static_cast<size_t>(c)]) : c;
+#else
+    return (isascii(c) && isupper_l(c, _LIBCPP_GET_C_LOCALE)) ? c-'A'+'a' : c;
+#endif
+}
+
+const char*
+ctype<char>::do_tolower(char_type* low, const char_type* high) const
+{
+    for (; low != high; ++low)
+#ifdef _LIBCPP_HAS_DEFAULTRUNELOCALE
+        *low = isascii(*low) ? static_cast<char>(_DefaultRuneLocale.__maplower[static_cast<ptrdiff_t>(*low)]) : *low;
+#elif defined(__NetBSD__)
+        *low = static_cast<char>(__classic_lower_table()[static_cast<unsigned char>(*low)]);
+#elif defined(__GLIBC__) || defined(__EMSCRIPTEN__)
+        *low = isascii(*low) ? static_cast<char>(__classic_lower_table()[static_cast<size_t>(*low)]) : *low;
+#else
+        *low = (isascii(*low) && isupper_l(*low, _LIBCPP_GET_C_LOCALE)) ? *low-'A'+'a' : *low;
+#endif
+    return low;
+}
+
+char
+ctype<char>::do_widen(char c) const
+{
+    return c;
+}
+
+const char*
+ctype<char>::do_widen(const char* low, const char* high, char_type* dest) const
+{
+    for (; low != high; ++low, ++dest)
+        *dest = *low;
+    return low;
+}
+
+char
+ctype<char>::do_narrow(char_type c, char dfault) const
+{
+    if (isascii(c))
+        return static_cast<char>(c);
+    return dfault;
+}
+
+const char*
+ctype<char>::do_narrow(const char_type* low, const char_type* high, char dfault, char* dest) const
+{
+    for (; low != high; ++low, ++dest)
+        if (isascii(*low))
+            *dest = *low;
+        else
+            *dest = dfault;
+    return low;
+}
+
+#if defined(__EMSCRIPTEN__)
+extern "C" const unsigned short ** __ctype_b_loc();
+extern "C" const int ** __ctype_tolower_loc();
+extern "C" const int ** __ctype_toupper_loc();
+#endif
+
+#if defined(__ANDROID__)
+// See src/support/android/android_locale.cpp
+extern "C" const unsigned short* const _ctype_android;
+#endif
+
+#ifdef _LIBCPP_PROVIDES_DEFAULT_RUNE_TABLE
+const ctype<char>::mask*
+ctype<char>::classic_table() noexcept
+{
+    static _LIBCPP_CONSTEXPR const ctype<char>::mask builtin_table[table_size] = {
+        cntrl,                          cntrl,
+        cntrl,                          cntrl,
+        cntrl,                          cntrl,
+        cntrl,                          cntrl,
+        cntrl,                          cntrl | space | blank,
+        cntrl | space,                  cntrl | space,
+        cntrl | space,                  cntrl | space,
+        cntrl,                          cntrl,
+        cntrl,                          cntrl,
+        cntrl,                          cntrl,
+        cntrl,                          cntrl,
+        cntrl,                          cntrl,
+        cntrl,                          cntrl,
+        cntrl,                          cntrl,
+        cntrl,                          cntrl,
+        cntrl,                          cntrl,
+        space | blank | print,          punct | print,
+        punct | print,                  punct | print,
+        punct | print,                  punct | print,
+        punct | print,                  punct | print,
+        punct | print,                  punct | print,
+        punct | print,                  punct | print,
+        punct | print,                  punct | print,
+        punct | print,                  punct | print,
+        digit | print | xdigit,         digit | print | xdigit,
+        digit | print | xdigit,         digit | print | xdigit,
+        digit | print | xdigit,         digit | print | xdigit,
+        digit | print | xdigit,         digit | print | xdigit,
+        digit | print | xdigit,         digit | print | xdigit,
+        punct | print,                  punct | print,
+        punct | print,                  punct | print,
+        punct | print,                  punct | print,
+        punct | print,                  upper | xdigit | print | alpha,
+        upper | xdigit | print | alpha, upper | xdigit | print | alpha,
+        upper | xdigit | print | alpha, upper | xdigit | print | alpha,
+        upper | xdigit | print | alpha, upper | print | alpha,
+        upper | print | alpha,          upper | print | alpha,
+        upper | print | alpha,          upper | print | alpha,
+        upper | print | alpha,          upper | print | alpha,
+        upper | print | alpha,          upper | print | alpha,
+        upper | print | alpha,          upper | print | alpha,
+        upper | print | alpha,          upper | print | alpha,
+        upper | print | alpha,          upper | print | alpha,
+        upper | print | alpha,          upper | print | alpha,
+        upper | print | alpha,          upper | print | alpha,
+        upper | print | alpha,          punct | print,
+        punct | print,                  punct | print,
+        punct | print,                  punct | print,
+        punct | print,                  lower | xdigit | print | alpha,
+        lower | xdigit | print | alpha, lower | xdigit | print | alpha,
+        lower | xdigit | print | alpha, lower | xdigit | print | alpha,
+        lower | xdigit | print | alpha, lower | print | alpha,
+        lower | print | alpha,          lower | print | alpha,
+        lower | print | alpha,          lower | print | alpha,
+        lower | print | alpha,          lower | print | alpha,
+        lower | print | alpha,          lower | print | alpha,
+        lower | print | alpha,          lower | print | alpha,
+        lower | print | alpha,          lower | print | alpha,
+        lower | print | alpha,          lower | print | alpha,
+        lower | print | alpha,          lower | print | alpha,
+        lower | print | alpha,          lower | print | alpha,
+        lower | print | alpha,          punct | print,
+        punct | print,                  punct | print,
+        punct | print,                  cntrl,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+    };
+    return builtin_table;
+}
+#else
+const ctype<char>::mask*
+ctype<char>::classic_table() noexcept
+{
+#if defined(__APPLE__) || defined(__FreeBSD__)
+    return _DefaultRuneLocale.__runetype;
+#elif defined(__NetBSD__)
+    return _C_ctype_tab_ + 1;
+#elif defined(__GLIBC__)
+    return _LIBCPP_GET_C_LOCALE->__ctype_b;
+#elif defined(__sun__)
+    return __ctype_mask;
+#elif defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
+    return __pctype_func();
+#elif defined(__EMSCRIPTEN__)
+    return *__ctype_b_loc();
+#elif defined(_NEWLIB_VERSION)
+    // Newlib has a 257-entry table in ctype_.c, where (char)0 starts at [1].
+    return _ctype_ + 1;
+#elif defined(__ANDROID__)
+    return _ctype_android;
+#elif defined(_AIX)
+    return (const unsigned int *)__lc_ctype_ptr->obj->mask;
+#else
+    // Platform not supported: abort so the person doing the port knows what to
+    // fix
+# warning  ctype<char>::classic_table() is not implemented
+    printf("ctype<char>::classic_table() is not implemented\n");
+    abort();
+    return NULL;
+#endif
+}
+#endif
+
+#if defined(__GLIBC__)
+const int*
+ctype<char>::__classic_lower_table() noexcept
+{
+    return _LIBCPP_GET_C_LOCALE->__ctype_tolower;
+}
+
+const int*
+ctype<char>::__classic_upper_table() noexcept
+{
+    return _LIBCPP_GET_C_LOCALE->__ctype_toupper;
+}
+#elif defined(__NetBSD__)
+const short*
+ctype<char>::__classic_lower_table() noexcept
+{
+    return _C_tolower_tab_ + 1;
+}
+
+const short*
+ctype<char>::__classic_upper_table() noexcept
+{
+    return _C_toupper_tab_ + 1;
+}
+
+#elif defined(__EMSCRIPTEN__)
+const int*
+ctype<char>::__classic_lower_table() noexcept
+{
+    return *__ctype_tolower_loc();
+}
+
+const int*
+ctype<char>::__classic_upper_table() noexcept
+{
+    return *__ctype_toupper_loc();
+}
+#endif // __GLIBC__ || __NETBSD__ || __EMSCRIPTEN__
+
+// template <> class ctype_byname<char>
+
+ctype_byname<char>::ctype_byname(const char* name, size_t refs)
+    : ctype<char>(0, false, refs),
+      __l(newlocale(LC_ALL_MASK, name, 0))
+{
+    if (__l == 0)
+        __throw_runtime_error("ctype_byname<char>::ctype_byname"
+                            " failed to construct for " + string(name));
+}
+
+ctype_byname<char>::ctype_byname(const string& name, size_t refs)
+    : ctype<char>(0, false, refs),
+      __l(newlocale(LC_ALL_MASK, name.c_str(), 0))
+{
+    if (__l == 0)
+        __throw_runtime_error("ctype_byname<char>::ctype_byname"
+                            " failed to construct for " + name);
+}
+
+ctype_byname<char>::~ctype_byname()
+{
+    freelocale(__l);
+}
+
+char
+ctype_byname<char>::do_toupper(char_type c) const
+{
+    return static_cast<char>(toupper_l(static_cast<unsigned char>(c), __l));
+}
+
+const char*
+ctype_byname<char>::do_toupper(char_type* low, const char_type* high) const
+{
+    for (; low != high; ++low)
+        *low = static_cast<char>(toupper_l(static_cast<unsigned char>(*low), __l));
+    return low;
+}
+
+char
+ctype_byname<char>::do_tolower(char_type c) const
+{
+    return static_cast<char>(tolower_l(static_cast<unsigned char>(c), __l));
+}
+
+const char*
+ctype_byname<char>::do_tolower(char_type* low, const char_type* high) const
+{
+    for (; low != high; ++low)
+        *low = static_cast<char>(tolower_l(static_cast<unsigned char>(*low), __l));
+    return low;
+}
+
+// template <> class ctype_byname<wchar_t>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+ctype_byname<wchar_t>::ctype_byname(const char* name, size_t refs)
+    : ctype<wchar_t>(refs),
+      __l(newlocale(LC_ALL_MASK, name, 0))
+{
+    if (__l == 0)
+        __throw_runtime_error("ctype_byname<wchar_t>::ctype_byname"
+                            " failed to construct for " + string(name));
+}
+
+ctype_byname<wchar_t>::ctype_byname(const string& name, size_t refs)
+    : ctype<wchar_t>(refs),
+      __l(newlocale(LC_ALL_MASK, name.c_str(), 0))
+{
+    if (__l == 0)
+        __throw_runtime_error("ctype_byname<wchar_t>::ctype_byname"
+                            " failed to construct for " + name);
+}
+
+ctype_byname<wchar_t>::~ctype_byname()
+{
+    freelocale(__l);
+}
+
+bool
+ctype_byname<wchar_t>::do_is(mask m, char_type c) const
+{
+#ifdef _LIBCPP_WCTYPE_IS_MASK
+    return static_cast<bool>(iswctype_l(c, m, __l));
+#else
+    bool result = false;
+    wint_t ch = static_cast<wint_t>(c);
+    if ((m & space) == space) result |= (iswspace_l(ch, __l) != 0);
+    if ((m & print) == print) result |= (iswprint_l(ch, __l) != 0);
+    if ((m & cntrl) == cntrl) result |= (iswcntrl_l(ch, __l) != 0);
+    if ((m & upper) == upper) result |= (iswupper_l(ch, __l) != 0);
+    if ((m & lower) == lower) result |= (iswlower_l(ch, __l) != 0);
+    if ((m & alpha) == alpha) result |= (iswalpha_l(ch, __l) != 0);
+    if ((m & digit) == digit) result |= (iswdigit_l(ch, __l) != 0);
+    if ((m & punct) == punct) result |= (iswpunct_l(ch, __l) != 0);
+    if ((m & xdigit) == xdigit) result |= (iswxdigit_l(ch, __l) != 0);
+    if ((m & blank) == blank) result |= (iswblank_l(ch, __l) != 0);
+    return result;
+#endif
+}
+
+const wchar_t*
+ctype_byname<wchar_t>::do_is(const char_type* low, const char_type* high, mask* vec) const
+{
+    for (; low != high; ++low, ++vec)
+    {
+        if (isascii(*low))
+            *vec = static_cast<mask>(ctype<char>::classic_table()[*low]);
+        else
+        {
+            *vec = 0;
+            wint_t ch = static_cast<wint_t>(*low);
+            if (iswspace_l(ch, __l))
+                *vec |= space;
+#ifndef _LIBCPP_CTYPE_MASK_IS_COMPOSITE_PRINT
+            if (iswprint_l(ch, __l))
+                *vec |= print;
+#endif
+            if (iswcntrl_l(ch, __l))
+                *vec |= cntrl;
+            if (iswupper_l(ch, __l))
+                *vec |= upper;
+            if (iswlower_l(ch, __l))
+                *vec |= lower;
+#ifndef _LIBCPP_CTYPE_MASK_IS_COMPOSITE_ALPHA
+            if (iswalpha_l(ch, __l))
+                *vec |= alpha;
+#endif
+            if (iswdigit_l(ch, __l))
+                *vec |= digit;
+            if (iswpunct_l(ch, __l))
+                *vec |= punct;
+#ifndef _LIBCPP_CTYPE_MASK_IS_COMPOSITE_XDIGIT
+            if (iswxdigit_l(ch, __l))
+                *vec |= xdigit;
+#endif
+#if !defined(__sun__)
+            if (iswblank_l(ch, __l))
+                *vec |= blank;
+#endif
+        }
+    }
+    return low;
+}
+
+const wchar_t*
+ctype_byname<wchar_t>::do_scan_is(mask m, const char_type* low, const char_type* high) const
+{
+    for (; low != high; ++low)
+    {
+#ifdef _LIBCPP_WCTYPE_IS_MASK
+        if (iswctype_l(*low, m, __l))
+            break;
+#else
+        wint_t ch = static_cast<wint_t>(*low);
+        if ((m & space) == space && iswspace_l(ch, __l)) break;
+        if ((m & print) == print && iswprint_l(ch, __l)) break;
+        if ((m & cntrl) == cntrl && iswcntrl_l(ch, __l)) break;
+        if ((m & upper) == upper && iswupper_l(ch, __l)) break;
+        if ((m & lower) == lower && iswlower_l(ch, __l)) break;
+        if ((m & alpha) == alpha && iswalpha_l(ch, __l)) break;
+        if ((m & digit) == digit && iswdigit_l(ch, __l)) break;
+        if ((m & punct) == punct && iswpunct_l(ch, __l)) break;
+        if ((m & xdigit) == xdigit && iswxdigit_l(ch, __l)) break;
+        if ((m & blank) == blank && iswblank_l(ch, __l)) break;
+#endif
+    }
+    return low;
+}
+
+const wchar_t*
+ctype_byname<wchar_t>::do_scan_not(mask m, const char_type* low, const char_type* high) const
+{
+    for (; low != high; ++low)
+    {
+#ifdef _LIBCPP_WCTYPE_IS_MASK
+        if (!iswctype_l(*low, m, __l))
+            break;
+#else
+        wint_t ch = static_cast<wint_t>(*low);
+        if ((m & space) == space && iswspace_l(ch, __l)) continue;
+        if ((m & print) == print && iswprint_l(ch, __l)) continue;
+        if ((m & cntrl) == cntrl && iswcntrl_l(ch, __l)) continue;
+        if ((m & upper) == upper && iswupper_l(ch, __l)) continue;
+        if ((m & lower) == lower && iswlower_l(ch, __l)) continue;
+        if ((m & alpha) == alpha && iswalpha_l(ch, __l)) continue;
+        if ((m & digit) == digit && iswdigit_l(ch, __l)) continue;
+        if ((m & punct) == punct && iswpunct_l(ch, __l)) continue;
+        if ((m & xdigit) == xdigit && iswxdigit_l(ch, __l)) continue;
+        if ((m & blank) == blank && iswblank_l(ch, __l)) continue;
+        break;
+#endif
+    }
+    return low;
+}
+
+wchar_t
+ctype_byname<wchar_t>::do_toupper(char_type c) const
+{
+    return towupper_l(c, __l);
+}
+
+const wchar_t*
+ctype_byname<wchar_t>::do_toupper(char_type* low, const char_type* high) const
+{
+    for (; low != high; ++low)
+        *low = towupper_l(*low, __l);
+    return low;
+}
+
+wchar_t
+ctype_byname<wchar_t>::do_tolower(char_type c) const
+{
+    return towlower_l(c, __l);
+}
+
+const wchar_t*
+ctype_byname<wchar_t>::do_tolower(char_type* low, const char_type* high) const
+{
+    for (; low != high; ++low)
+        *low = towlower_l(*low, __l);
+    return low;
+}
+
+wchar_t
+ctype_byname<wchar_t>::do_widen(char c) const
+{
+    return __libcpp_btowc_l(c, __l);
+}
+
+const char*
+ctype_byname<wchar_t>::do_widen(const char* low, const char* high, char_type* dest) const
+{
+    for (; low != high; ++low, ++dest)
+        *dest = __libcpp_btowc_l(*low, __l);
+    return low;
+}
+
+char
+ctype_byname<wchar_t>::do_narrow(char_type c, char dfault) const
+{
+    int r = __libcpp_wctob_l(c, __l);
+    return r != static_cast<int>(WEOF) ? static_cast<char>(r) : dfault;
+}
+
+const wchar_t*
+ctype_byname<wchar_t>::do_narrow(const char_type* low, const char_type* high, char dfault, char* dest) const
+{
+    for (; low != high; ++low, ++dest)
+    {
+        int r = __libcpp_wctob_l(*low, __l);
+        *dest = r != static_cast<int>(WEOF) ? static_cast<char>(r) : dfault;
+    }
+    return low;
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// template <> class codecvt<char, char, mbstate_t>
+
+locale::id codecvt<char, char, mbstate_t>::id;
+
+codecvt<char, char, mbstate_t>::~codecvt()
+{
+}
+
+codecvt<char, char, mbstate_t>::result
+codecvt<char, char, mbstate_t>::do_out(state_type&,
+    const intern_type* frm, const intern_type*, const intern_type*& frm_nxt,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    return noconv;
+}
+
+codecvt<char, char, mbstate_t>::result
+codecvt<char, char, mbstate_t>::do_in(state_type&,
+    const extern_type* frm, const extern_type*, const extern_type*& frm_nxt,
+    intern_type* to, intern_type*, intern_type*& to_nxt) const
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    return noconv;
+}
+
+codecvt<char, char, mbstate_t>::result
+codecvt<char, char, mbstate_t>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+codecvt<char, char, mbstate_t>::do_encoding() const noexcept
+{
+    return 1;
+}
+
+bool
+codecvt<char, char, mbstate_t>::do_always_noconv() const noexcept
+{
+    return true;
+}
+
+int
+codecvt<char, char, mbstate_t>::do_length(state_type&,
+    const extern_type* frm, const extern_type* end, size_t mx) const
+{
+    return static_cast<int>(min<size_t>(mx, static_cast<size_t>(end-frm)));
+}
+
+int
+codecvt<char, char, mbstate_t>::do_max_length() const noexcept
+{
+    return 1;
+}
+
+// template <> class codecvt<wchar_t, char, mbstate_t>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+locale::id codecvt<wchar_t, char, mbstate_t>::id;
+
+codecvt<wchar_t, char, mbstate_t>::codecvt(size_t refs)
+    : locale::facet(refs),
+      __l(_LIBCPP_GET_C_LOCALE)
+{
+}
+
+codecvt<wchar_t, char, mbstate_t>::codecvt(const char* nm, size_t refs)
+    : locale::facet(refs),
+      __l(newlocale(LC_ALL_MASK, nm, 0))
+{
+    if (__l == 0)
+        __throw_runtime_error("codecvt_byname<wchar_t, char, mbstate_t>::codecvt_byname"
+                            " failed to construct for " + string(nm));
+}
+
+codecvt<wchar_t, char, mbstate_t>::~codecvt()
+{
+    if (__l != _LIBCPP_GET_C_LOCALE)
+        freelocale(__l);
+}
+
+codecvt<wchar_t, char, mbstate_t>::result
+codecvt<wchar_t, char, mbstate_t>::do_out(state_type& st,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+    // look for first internal null in frm
+    const intern_type* fend = frm;
+    for (; fend != frm_end; ++fend)
+        if (*fend == 0)
+            break;
+    // loop over all null-terminated sequences in frm
+    to_nxt = to;
+    for (frm_nxt = frm; frm != frm_end && to != to_end; frm = frm_nxt, to = to_nxt)
+    {
+        // save state in case it is needed to recover to_nxt on error
+        mbstate_t save_state = st;
+        size_t n = __libcpp_wcsnrtombs_l(to, &frm_nxt, static_cast<size_t>(fend-frm),
+                                     static_cast<size_t>(to_end-to), &st, __l);
+        if (n == size_t(-1))
+        {
+            // need to recover to_nxt
+            for (to_nxt = to; frm != frm_nxt; ++frm)
+            {
+                n = __libcpp_wcrtomb_l(to_nxt, *frm, &save_state, __l);
+                if (n == size_t(-1))
+                    break;
+                to_nxt += n;
+            }
+            frm_nxt = frm;
+            return error;
+        }
+        if (n == 0)
+            return partial;
+        to_nxt += n;
+        if (to_nxt == to_end)
+            break;
+        if (fend != frm_end)  // set up next null terminated sequence
+        {
+            // Try to write the terminating null
+            extern_type tmp[MB_LEN_MAX];
+            n = __libcpp_wcrtomb_l(tmp, intern_type(), &st, __l);
+            if (n == size_t(-1))  // on error
+                return error;
+            if (n > static_cast<size_t>(to_end-to_nxt))  // is there room?
+                return partial;
+            for (extern_type* p = tmp; n; --n)  // write it
+                *to_nxt++ = *p++;
+            ++frm_nxt;
+            // look for next null in frm
+            for (fend = frm_nxt; fend != frm_end; ++fend)
+                if (*fend == 0)
+                    break;
+        }
+    }
+    return frm_nxt == frm_end ? ok : partial;
+}
+
+codecvt<wchar_t, char, mbstate_t>::result
+codecvt<wchar_t, char, mbstate_t>::do_in(state_type& st,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    // look for first internal null in frm
+    const extern_type* fend = frm;
+    for (; fend != frm_end; ++fend)
+        if (*fend == 0)
+            break;
+    // loop over all null-terminated sequences in frm
+    to_nxt = to;
+    for (frm_nxt = frm; frm != frm_end && to != to_end; frm = frm_nxt, to = to_nxt)
+    {
+        // save state in case it is needed to recover to_nxt on error
+        mbstate_t save_state = st;
+        size_t n = __libcpp_mbsnrtowcs_l(to, &frm_nxt, static_cast<size_t>(fend-frm),
+                                     static_cast<size_t>(to_end-to), &st, __l);
+        if (n == size_t(-1))
+        {
+            // need to recover to_nxt
+            for (to_nxt = to; frm != frm_nxt; ++to_nxt)
+            {
+                n = __libcpp_mbrtowc_l(to_nxt, frm, static_cast<size_t>(fend-frm),
+                                   &save_state, __l);
+                switch (n)
+                {
+                case 0:
+                    ++frm;
+                    break;
+                case size_t(-1):
+                    frm_nxt = frm;
+                    return error;
+                case size_t(-2):
+                    frm_nxt = frm;
+                    return partial;
+                default:
+                    frm += n;
+                    break;
+                }
+            }
+            frm_nxt = frm;
+            return frm_nxt == frm_end ? ok : partial;
+        }
+        if (n == size_t(-1))
+            return error;
+        to_nxt += n;
+        if (to_nxt == to_end)
+            break;
+        if (fend != frm_end)  // set up next null terminated sequence
+        {
+            // Try to write the terminating null
+            n = __libcpp_mbrtowc_l(to_nxt, frm_nxt, 1, &st, __l);
+            if (n != 0)  // on error
+                return error;
+            ++to_nxt;
+            ++frm_nxt;
+            // look for next null in frm
+            for (fend = frm_nxt; fend != frm_end; ++fend)
+                if (*fend == 0)
+                    break;
+        }
+    }
+    return frm_nxt == frm_end ? ok : partial;
+}
+
+codecvt<wchar_t, char, mbstate_t>::result
+codecvt<wchar_t, char, mbstate_t>::do_unshift(state_type& st,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    extern_type tmp[MB_LEN_MAX];
+    size_t n = __libcpp_wcrtomb_l(tmp, intern_type(), &st, __l);
+    if (n == size_t(-1) || n == 0)  // on error
+        return error;
+    --n;
+    if (n > static_cast<size_t>(to_end-to_nxt))  // is there room?
+        return partial;
+    for (extern_type* p = tmp; n; --n)  // write it
+        *to_nxt++ = *p++;
+    return ok;
+}
+
+int
+codecvt<wchar_t, char, mbstate_t>::do_encoding() const noexcept
+{
+    if (__libcpp_mbtowc_l(nullptr, nullptr, MB_LEN_MAX, __l) != 0)
+        return -1;
+
+    // stateless encoding
+    if (__l == 0 || __libcpp_mb_cur_max_l(__l) == 1)  // there are no known constant length encodings
+        return 1;                // which take more than 1 char to form a wchar_t
+    return 0;
+}
+
+bool
+codecvt<wchar_t, char, mbstate_t>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+codecvt<wchar_t, char, mbstate_t>::do_length(state_type& st,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    int nbytes = 0;
+    for (size_t nwchar_t = 0; nwchar_t < mx && frm != frm_end; ++nwchar_t)
+    {
+        size_t n = __libcpp_mbrlen_l(frm, static_cast<size_t>(frm_end-frm), &st, __l);
+        switch (n)
+        {
+        case 0:
+            ++nbytes;
+            ++frm;
+            break;
+        case size_t(-1):
+        case size_t(-2):
+            return nbytes;
+        default:
+            nbytes += n;
+            frm += n;
+            break;
+        }
+    }
+    return nbytes;
+}
+
+int
+codecvt<wchar_t, char, mbstate_t>::do_max_length() const noexcept
+{
+    return __l == 0 ? 1 : static_cast<int>(__libcpp_mb_cur_max_l(__l));
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+//                                     Valid UTF ranges
+//     UTF-32               UTF-16                          UTF-8               # of code points
+//                     first      second       first   second    third   fourth
+// 000000 - 00007F  0000 - 007F               00 - 7F                                 127
+// 000080 - 0007FF  0080 - 07FF               C2 - DF, 80 - BF                       1920
+// 000800 - 000FFF  0800 - 0FFF               E0 - E0, A0 - BF, 80 - BF              2048
+// 001000 - 00CFFF  1000 - CFFF               E1 - EC, 80 - BF, 80 - BF             49152
+// 00D000 - 00D7FF  D000 - D7FF               ED - ED, 80 - 9F, 80 - BF              2048
+// 00D800 - 00DFFF                invalid
+// 00E000 - 00FFFF  E000 - FFFF               EE - EF, 80 - BF, 80 - BF              8192
+// 010000 - 03FFFF  D800 - D8BF, DC00 - DFFF  F0 - F0, 90 - BF, 80 - BF, 80 - BF   196608
+// 040000 - 0FFFFF  D8C0 - DBBF, DC00 - DFFF  F1 - F3, 80 - BF, 80 - BF, 80 - BF   786432
+// 100000 - 10FFFF  DBC0 - DBFF, DC00 - DFFF  F4 - F4, 80 - 8F, 80 - BF, 80 - BF    65536
+
+static
+codecvt_base::result
+utf16_to_utf8(const uint16_t* frm, const uint16_t* frm_end, const uint16_t*& frm_nxt,
+              uint8_t* to, uint8_t* to_end, uint8_t*& to_nxt,
+              unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & generate_header)
+    {
+        if (to_end-to_nxt < 3)
+            return codecvt_base::partial;
+        *to_nxt++ = static_cast<uint8_t>(0xEF);
+        *to_nxt++ = static_cast<uint8_t>(0xBB);
+        *to_nxt++ = static_cast<uint8_t>(0xBF);
+    }
+    for (; frm_nxt < frm_end; ++frm_nxt)
+    {
+        uint16_t wc1 = *frm_nxt;
+        if (wc1 > Maxcode)
+            return codecvt_base::error;
+        if (wc1 < 0x0080)
+        {
+            if (to_end-to_nxt < 1)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(wc1);
+        }
+        else if (wc1 < 0x0800)
+        {
+            if (to_end-to_nxt < 2)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(0xC0 | (wc1 >> 6));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | (wc1 & 0x03F));
+        }
+        else if (wc1 < 0xD800)
+        {
+            if (to_end-to_nxt < 3)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(0xE0 |  (wc1 >> 12));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | ((wc1 & 0x0FC0) >> 6));
+            *to_nxt++ = static_cast<uint8_t>(0x80 |  (wc1 & 0x003F));
+        }
+        else if (wc1 < 0xDC00)
+        {
+            if (frm_end-frm_nxt < 2)
+                return codecvt_base::partial;
+            uint16_t wc2 = frm_nxt[1];
+            if ((wc2 & 0xFC00) != 0xDC00)
+                return codecvt_base::error;
+            if (to_end-to_nxt < 4)
+                return codecvt_base::partial;
+            if (((((wc1 & 0x03C0UL) >> 6) + 1) << 16) +
+                ((wc1 & 0x003FUL) << 10) + (wc2 & 0x03FF) > Maxcode)
+                return codecvt_base::error;
+            ++frm_nxt;
+            uint8_t z = ((wc1 & 0x03C0) >> 6) + 1;
+            *to_nxt++ = static_cast<uint8_t>(0xF0 | (z >> 2));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | ((z & 0x03) << 4)     | ((wc1 & 0x003C) >> 2));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | ((wc1 & 0x0003) << 4) | ((wc2 & 0x03C0) >> 6));
+            *to_nxt++ = static_cast<uint8_t>(0x80 |  (wc2 & 0x003F));
+        }
+        else if (wc1 < 0xE000)
+        {
+            return codecvt_base::error;
+        }
+        else
+        {
+            if (to_end-to_nxt < 3)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(0xE0 |  (wc1 >> 12));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | ((wc1 & 0x0FC0) >> 6));
+            *to_nxt++ = static_cast<uint8_t>(0x80 |  (wc1 & 0x003F));
+        }
+    }
+    return codecvt_base::ok;
+}
+
+static
+codecvt_base::result
+utf16_to_utf8(const uint32_t* frm, const uint32_t* frm_end, const uint32_t*& frm_nxt,
+              uint8_t* to, uint8_t* to_end, uint8_t*& to_nxt,
+              unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & generate_header)
+    {
+        if (to_end-to_nxt < 3)
+            return codecvt_base::partial;
+        *to_nxt++ = static_cast<uint8_t>(0xEF);
+        *to_nxt++ = static_cast<uint8_t>(0xBB);
+        *to_nxt++ = static_cast<uint8_t>(0xBF);
+    }
+    for (; frm_nxt < frm_end; ++frm_nxt)
+    {
+        uint16_t wc1 = static_cast<uint16_t>(*frm_nxt);
+        if (wc1 > Maxcode)
+            return codecvt_base::error;
+        if (wc1 < 0x0080)
+        {
+            if (to_end-to_nxt < 1)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(wc1);
+        }
+        else if (wc1 < 0x0800)
+        {
+            if (to_end-to_nxt < 2)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(0xC0 | (wc1 >> 6));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | (wc1 & 0x03F));
+        }
+        else if (wc1 < 0xD800)
+        {
+            if (to_end-to_nxt < 3)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(0xE0 |  (wc1 >> 12));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | ((wc1 & 0x0FC0) >> 6));
+            *to_nxt++ = static_cast<uint8_t>(0x80 |  (wc1 & 0x003F));
+        }
+        else if (wc1 < 0xDC00)
+        {
+            if (frm_end-frm_nxt < 2)
+                return codecvt_base::partial;
+            uint16_t wc2 = static_cast<uint16_t>(frm_nxt[1]);
+            if ((wc2 & 0xFC00) != 0xDC00)
+                return codecvt_base::error;
+            if (to_end-to_nxt < 4)
+                return codecvt_base::partial;
+            if (((((wc1 & 0x03C0UL) >> 6) + 1) << 16) +
+                ((wc1 & 0x003FUL) << 10) + (wc2 & 0x03FF) > Maxcode)
+                return codecvt_base::error;
+            ++frm_nxt;
+            uint8_t z = ((wc1 & 0x03C0) >> 6) + 1;
+            *to_nxt++ = static_cast<uint8_t>(0xF0 | (z >> 2));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | ((z & 0x03) << 4)     | ((wc1 & 0x003C) >> 2));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | ((wc1 & 0x0003) << 4) | ((wc2 & 0x03C0) >> 6));
+            *to_nxt++ = static_cast<uint8_t>(0x80 |  (wc2 & 0x003F));
+        }
+        else if (wc1 < 0xE000)
+        {
+            return codecvt_base::error;
+        }
+        else
+        {
+            if (to_end-to_nxt < 3)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(0xE0 |  (wc1 >> 12));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | ((wc1 & 0x0FC0) >> 6));
+            *to_nxt++ = static_cast<uint8_t>(0x80 |  (wc1 & 0x003F));
+        }
+    }
+    return codecvt_base::ok;
+}
+
+static
+codecvt_base::result
+utf8_to_utf16(const uint8_t* frm, const uint8_t* frm_end, const uint8_t*& frm_nxt,
+              uint16_t* to, uint16_t* to_end, uint16_t*& to_nxt,
+              unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 3 && frm_nxt[0] == 0xEF && frm_nxt[1] == 0xBB &&
+                                                          frm_nxt[2] == 0xBF)
+            frm_nxt += 3;
+    }
+    for (; frm_nxt < frm_end && to_nxt < to_end; ++to_nxt)
+    {
+        uint8_t c1 = *frm_nxt;
+        if (c1 > Maxcode)
+            return codecvt_base::error;
+        if (c1 < 0x80)
+        {
+            *to_nxt = static_cast<uint16_t>(c1);
+            ++frm_nxt;
+        }
+        else if (c1 < 0xC2)
+        {
+            return codecvt_base::error;
+        }
+        else if (c1 < 0xE0)
+        {
+            if (frm_end-frm_nxt < 2)
+                return codecvt_base::partial;
+            uint8_t c2 = frm_nxt[1];
+            if ((c2 & 0xC0) != 0x80)
+                return codecvt_base::error;
+            uint16_t t = static_cast<uint16_t>(((c1 & 0x1F) << 6) | (c2 & 0x3F));
+            if (t > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = t;
+            frm_nxt += 2;
+        }
+        else if (c1 < 0xF0)
+        {
+            if (frm_end-frm_nxt < 3)
+                return codecvt_base::partial;
+            uint8_t c2 = frm_nxt[1];
+            uint8_t c3 = frm_nxt[2];
+            switch (c1)
+            {
+            case 0xE0:
+                if ((c2 & 0xE0) != 0xA0)
+                    return codecvt_base::error;
+                 break;
+            case 0xED:
+                if ((c2 & 0xE0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            default:
+                if ((c2 & 0xC0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            }
+            if ((c3 & 0xC0) != 0x80)
+                return codecvt_base::error;
+            uint16_t t = static_cast<uint16_t>(((c1 & 0x0F) << 12)
+                                             | ((c2 & 0x3F) << 6)
+                                             |  (c3 & 0x3F));
+            if (t > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = t;
+            frm_nxt += 3;
+        }
+        else if (c1 < 0xF5)
+        {
+            if (frm_end-frm_nxt < 4)
+                return codecvt_base::partial;
+            uint8_t c2 = frm_nxt[1];
+            uint8_t c3 = frm_nxt[2];
+            uint8_t c4 = frm_nxt[3];
+            switch (c1)
+            {
+            case 0xF0:
+                if (!(0x90 <= c2 && c2 <= 0xBF))
+                    return codecvt_base::error;
+                 break;
+            case 0xF4:
+                if ((c2 & 0xF0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            default:
+                if ((c2 & 0xC0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            }
+            if ((c3 & 0xC0) != 0x80 || (c4 & 0xC0) != 0x80)
+                return codecvt_base::error;
+            if (to_end-to_nxt < 2)
+                return codecvt_base::partial;
+            if ((((c1 & 7UL) << 18) +
+                ((c2 & 0x3FUL) << 12) +
+                ((c3 & 0x3FUL) << 6) + (c4 & 0x3F)) > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = static_cast<uint16_t>(
+                    0xD800
+                  | (((((c1 & 0x07) << 2) | ((c2 & 0x30) >> 4)) - 1) << 6)
+                  | ((c2 & 0x0F) << 2)
+                  | ((c3 & 0x30) >> 4));
+            *++to_nxt = static_cast<uint16_t>(
+                    0xDC00
+                  | ((c3 & 0x0F) << 6)
+                  |  (c4 & 0x3F));
+            frm_nxt += 4;
+        }
+        else
+        {
+            return codecvt_base::error;
+        }
+    }
+    return frm_nxt < frm_end ? codecvt_base::partial : codecvt_base::ok;
+}
+
+static
+codecvt_base::result
+utf8_to_utf16(const uint8_t* frm, const uint8_t* frm_end, const uint8_t*& frm_nxt,
+              uint32_t* to, uint32_t* to_end, uint32_t*& to_nxt,
+              unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 3 && frm_nxt[0] == 0xEF && frm_nxt[1] == 0xBB &&
+                                                          frm_nxt[2] == 0xBF)
+            frm_nxt += 3;
+    }
+    for (; frm_nxt < frm_end && to_nxt < to_end; ++to_nxt)
+    {
+        uint8_t c1 = *frm_nxt;
+        if (c1 > Maxcode)
+            return codecvt_base::error;
+        if (c1 < 0x80)
+        {
+            *to_nxt = static_cast<uint32_t>(c1);
+            ++frm_nxt;
+        }
+        else if (c1 < 0xC2)
+        {
+            return codecvt_base::error;
+        }
+        else if (c1 < 0xE0)
+        {
+            if (frm_end-frm_nxt < 2)
+                return codecvt_base::partial;
+            uint8_t c2 = frm_nxt[1];
+            if ((c2 & 0xC0) != 0x80)
+                return codecvt_base::error;
+            uint16_t t = static_cast<uint16_t>(((c1 & 0x1F) << 6) | (c2 & 0x3F));
+            if (t > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = static_cast<uint32_t>(t);
+            frm_nxt += 2;
+        }
+        else if (c1 < 0xF0)
+        {
+            if (frm_end-frm_nxt < 3)
+                return codecvt_base::partial;
+            uint8_t c2 = frm_nxt[1];
+            uint8_t c3 = frm_nxt[2];
+            switch (c1)
+            {
+            case 0xE0:
+                if ((c2 & 0xE0) != 0xA0)
+                    return codecvt_base::error;
+                 break;
+            case 0xED:
+                if ((c2 & 0xE0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            default:
+                if ((c2 & 0xC0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            }
+            if ((c3 & 0xC0) != 0x80)
+                return codecvt_base::error;
+            uint16_t t = static_cast<uint16_t>(((c1 & 0x0F) << 12)
+                                             | ((c2 & 0x3F) << 6)
+                                             |  (c3 & 0x3F));
+            if (t > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = static_cast<uint32_t>(t);
+            frm_nxt += 3;
+        }
+        else if (c1 < 0xF5)
+        {
+            if (frm_end-frm_nxt < 4)
+                return codecvt_base::partial;
+            uint8_t c2 = frm_nxt[1];
+            uint8_t c3 = frm_nxt[2];
+            uint8_t c4 = frm_nxt[3];
+            switch (c1)
+            {
+            case 0xF0:
+                if (!(0x90 <= c2 && c2 <= 0xBF))
+                    return codecvt_base::error;
+                 break;
+            case 0xF4:
+                if ((c2 & 0xF0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            default:
+                if ((c2 & 0xC0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            }
+            if ((c3 & 0xC0) != 0x80 || (c4 & 0xC0) != 0x80)
+                return codecvt_base::error;
+            if (to_end-to_nxt < 2)
+                return codecvt_base::partial;
+            if ((((c1 & 7UL) << 18) +
+                ((c2 & 0x3FUL) << 12) +
+                ((c3 & 0x3FUL) << 6) + (c4 & 0x3F)) > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = static_cast<uint32_t>(
+                    0xD800
+                  | (((((c1 & 0x07) << 2) | ((c2 & 0x30) >> 4)) - 1) << 6)
+                  | ((c2 & 0x0F) << 2)
+                  | ((c3 & 0x30) >> 4));
+            *++to_nxt = static_cast<uint32_t>(
+                    0xDC00
+                  | ((c3 & 0x0F) << 6)
+                  |  (c4 & 0x3F));
+            frm_nxt += 4;
+        }
+        else
+        {
+            return codecvt_base::error;
+        }
+    }
+    return frm_nxt < frm_end ? codecvt_base::partial : codecvt_base::ok;
+}
+
+static
+int
+utf8_to_utf16_length(const uint8_t* frm, const uint8_t* frm_end,
+                     size_t mx, unsigned long Maxcode = 0x10FFFF,
+                     codecvt_mode mode = codecvt_mode(0))
+{
+    const uint8_t* frm_nxt = frm;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 3 && frm_nxt[0] == 0xEF && frm_nxt[1] == 0xBB &&
+                                                          frm_nxt[2] == 0xBF)
+            frm_nxt += 3;
+    }
+    for (size_t nchar16_t = 0; frm_nxt < frm_end && nchar16_t < mx; ++nchar16_t)
+    {
+        uint8_t c1 = *frm_nxt;
+        if (c1 > Maxcode)
+            break;
+        if (c1 < 0x80)
+        {
+            ++frm_nxt;
+        }
+        else if (c1 < 0xC2)
+        {
+            break;
+        }
+        else if (c1 < 0xE0)
+        {
+            if ((frm_end-frm_nxt < 2) || (frm_nxt[1] & 0xC0) != 0x80)
+                break;
+            uint16_t t = static_cast<uint16_t>(((c1 & 0x1F) << 6) | (frm_nxt[1] & 0x3F));
+            if (t > Maxcode)
+                break;
+            frm_nxt += 2;
+        }
+        else if (c1 < 0xF0)
+        {
+            if (frm_end-frm_nxt < 3)
+                break;
+            uint8_t c2 = frm_nxt[1];
+            uint8_t c3 = frm_nxt[2];
+            switch (c1)
+            {
+            case 0xE0:
+                if ((c2 & 0xE0) != 0xA0)
+                    return static_cast<int>(frm_nxt - frm);
+                break;
+            case 0xED:
+                if ((c2 & 0xE0) != 0x80)
+                    return static_cast<int>(frm_nxt - frm);
+                 break;
+            default:
+                if ((c2 & 0xC0) != 0x80)
+                    return static_cast<int>(frm_nxt - frm);
+                 break;
+            }
+            if ((c3 & 0xC0) != 0x80)
+                break;
+            if ((((c1 & 0x0Fu) << 12) | ((c2 & 0x3Fu) << 6) | (c3 & 0x3Fu)) > Maxcode)
+                break;
+            frm_nxt += 3;
+        }
+        else if (c1 < 0xF5)
+        {
+            if (frm_end-frm_nxt < 4 || mx-nchar16_t < 2)
+                break;
+            uint8_t c2 = frm_nxt[1];
+            uint8_t c3 = frm_nxt[2];
+            uint8_t c4 = frm_nxt[3];
+            switch (c1)
+            {
+            case 0xF0:
+                if (!(0x90 <= c2 && c2 <= 0xBF))
+                    return static_cast<int>(frm_nxt - frm);
+                 break;
+            case 0xF4:
+                if ((c2 & 0xF0) != 0x80)
+                    return static_cast<int>(frm_nxt - frm);
+                 break;
+            default:
+                if ((c2 & 0xC0) != 0x80)
+                    return static_cast<int>(frm_nxt - frm);
+                 break;
+            }
+            if ((c3 & 0xC0) != 0x80 || (c4 & 0xC0) != 0x80)
+                break;
+            if ((((c1 & 7UL) << 18) +
+                ((c2 & 0x3FUL) << 12) +
+                ((c3 & 0x3FUL) << 6) + (c4 & 0x3F)) > Maxcode)
+                break;
+            ++nchar16_t;
+            frm_nxt += 4;
+        }
+        else
+        {
+            break;
+        }
+    }
+    return static_cast<int>(frm_nxt - frm);
+}
+
+static
+codecvt_base::result
+ucs4_to_utf8(const uint32_t* frm, const uint32_t* frm_end, const uint32_t*& frm_nxt,
+             uint8_t* to, uint8_t* to_end, uint8_t*& to_nxt,
+             unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & generate_header)
+    {
+        if (to_end-to_nxt < 3)
+            return codecvt_base::partial;
+        *to_nxt++ = static_cast<uint8_t>(0xEF);
+        *to_nxt++ = static_cast<uint8_t>(0xBB);
+        *to_nxt++ = static_cast<uint8_t>(0xBF);
+    }
+    for (; frm_nxt < frm_end; ++frm_nxt)
+    {
+        uint32_t wc = *frm_nxt;
+        if ((wc & 0xFFFFF800) == 0x00D800 || wc > Maxcode)
+            return codecvt_base::error;
+        if (wc < 0x000080)
+        {
+            if (to_end-to_nxt < 1)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(wc);
+        }
+        else if (wc < 0x000800)
+        {
+            if (to_end-to_nxt < 2)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(0xC0 | (wc >> 6));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | (wc & 0x03F));
+        }
+        else if (wc < 0x010000)
+        {
+            if (to_end-to_nxt < 3)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(0xE0 |  (wc >> 12));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | ((wc & 0x0FC0) >> 6));
+            *to_nxt++ = static_cast<uint8_t>(0x80 |  (wc & 0x003F));
+        }
+        else // if (wc < 0x110000)
+        {
+            if (to_end-to_nxt < 4)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(0xF0 |  (wc >> 18));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | ((wc & 0x03F000) >> 12));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | ((wc & 0x000FC0) >> 6));
+            *to_nxt++ = static_cast<uint8_t>(0x80 |  (wc & 0x00003F));
+        }
+    }
+    return codecvt_base::ok;
+}
+
+static
+codecvt_base::result
+utf8_to_ucs4(const uint8_t* frm, const uint8_t* frm_end, const uint8_t*& frm_nxt,
+             uint32_t* to, uint32_t* to_end, uint32_t*& to_nxt,
+             unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 3 && frm_nxt[0] == 0xEF && frm_nxt[1] == 0xBB &&
+                                                          frm_nxt[2] == 0xBF)
+            frm_nxt += 3;
+    }
+    for (; frm_nxt < frm_end && to_nxt < to_end; ++to_nxt)
+    {
+        uint8_t c1 = static_cast<uint8_t>(*frm_nxt);
+        if (c1 < 0x80)
+        {
+            if (c1 > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = static_cast<uint32_t>(c1);
+            ++frm_nxt;
+        }
+        else if (c1 < 0xC2)
+        {
+            return codecvt_base::error;
+        }
+        else if (c1 < 0xE0)
+        {
+            if (frm_end-frm_nxt < 2)
+                return codecvt_base::partial;
+            uint8_t c2 = frm_nxt[1];
+            if ((c2 & 0xC0) != 0x80)
+                return codecvt_base::error;
+            uint32_t t = static_cast<uint32_t>(((c1 & 0x1F) << 6)
+                                              | (c2 & 0x3F));
+            if (t > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = t;
+            frm_nxt += 2;
+        }
+        else if (c1 < 0xF0)
+        {
+            if (frm_end-frm_nxt < 3)
+                return codecvt_base::partial;
+            uint8_t c2 = frm_nxt[1];
+            uint8_t c3 = frm_nxt[2];
+            switch (c1)
+            {
+            case 0xE0:
+                if ((c2 & 0xE0) != 0xA0)
+                    return codecvt_base::error;
+                 break;
+            case 0xED:
+                if ((c2 & 0xE0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            default:
+                if ((c2 & 0xC0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            }
+            if ((c3 & 0xC0) != 0x80)
+                return codecvt_base::error;
+            uint32_t t = static_cast<uint32_t>(((c1 & 0x0F) << 12)
+                                             | ((c2 & 0x3F) << 6)
+                                             |  (c3 & 0x3F));
+            if (t > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = t;
+            frm_nxt += 3;
+        }
+        else if (c1 < 0xF5)
+        {
+            if (frm_end-frm_nxt < 4)
+                return codecvt_base::partial;
+            uint8_t c2 = frm_nxt[1];
+            uint8_t c3 = frm_nxt[2];
+            uint8_t c4 = frm_nxt[3];
+            switch (c1)
+            {
+            case 0xF0:
+                if (!(0x90 <= c2 && c2 <= 0xBF))
+                    return codecvt_base::error;
+                 break;
+            case 0xF4:
+                if ((c2 & 0xF0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            default:
+                if ((c2 & 0xC0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            }
+            if ((c3 & 0xC0) != 0x80 || (c4 & 0xC0) != 0x80)
+                return codecvt_base::error;
+            uint32_t t = static_cast<uint32_t>(((c1 & 0x07) << 18)
+                                             | ((c2 & 0x3F) << 12)
+                                             | ((c3 & 0x3F) << 6)
+                                             |  (c4 & 0x3F));
+            if (t > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = t;
+            frm_nxt += 4;
+        }
+        else
+        {
+            return codecvt_base::error;
+        }
+    }
+    return frm_nxt < frm_end ? codecvt_base::partial : codecvt_base::ok;
+}
+
+static
+int
+utf8_to_ucs4_length(const uint8_t* frm, const uint8_t* frm_end,
+                    size_t mx, unsigned long Maxcode = 0x10FFFF,
+                    codecvt_mode mode = codecvt_mode(0))
+{
+    const uint8_t* frm_nxt = frm;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 3 && frm_nxt[0] == 0xEF && frm_nxt[1] == 0xBB &&
+                                                          frm_nxt[2] == 0xBF)
+            frm_nxt += 3;
+    }
+    for (size_t nchar32_t = 0; frm_nxt < frm_end && nchar32_t < mx; ++nchar32_t)
+    {
+        uint8_t c1 = static_cast<uint8_t>(*frm_nxt);
+        if (c1 < 0x80)
+        {
+            if (c1 > Maxcode)
+                break;
+            ++frm_nxt;
+        }
+        else if (c1 < 0xC2)
+        {
+            break;
+        }
+        else if (c1 < 0xE0)
+        {
+            if ((frm_end-frm_nxt < 2) || ((frm_nxt[1] & 0xC0) != 0x80))
+                break;
+            if ((((c1 & 0x1Fu) << 6) | (frm_nxt[1] & 0x3Fu)) > Maxcode)
+                break;
+            frm_nxt += 2;
+        }
+        else if (c1 < 0xF0)
+        {
+            if (frm_end-frm_nxt < 3)
+                break;
+            uint8_t c2 = frm_nxt[1];
+            uint8_t c3 = frm_nxt[2];
+            switch (c1)
+            {
+            case 0xE0:
+                if ((c2 & 0xE0) != 0xA0)
+                    return static_cast<int>(frm_nxt - frm);
+                break;
+            case 0xED:
+                if ((c2 & 0xE0) != 0x80)
+                    return static_cast<int>(frm_nxt - frm);
+                 break;
+            default:
+                if ((c2 & 0xC0) != 0x80)
+                    return static_cast<int>(frm_nxt - frm);
+                 break;
+            }
+            if ((c3 & 0xC0) != 0x80)
+                break;
+            if ((((c1 & 0x0Fu) << 12) | ((c2 & 0x3Fu) << 6) | (c3 & 0x3Fu)) > Maxcode)
+                break;
+            frm_nxt += 3;
+        }
+        else if (c1 < 0xF5)
+        {
+            if (frm_end-frm_nxt < 4)
+                break;
+            uint8_t c2 = frm_nxt[1];
+            uint8_t c3 = frm_nxt[2];
+            uint8_t c4 = frm_nxt[3];
+            switch (c1)
+            {
+            case 0xF0:
+                if (!(0x90 <= c2 && c2 <= 0xBF))
+                    return static_cast<int>(frm_nxt - frm);
+                 break;
+            case 0xF4:
+                if ((c2 & 0xF0) != 0x80)
+                    return static_cast<int>(frm_nxt - frm);
+                 break;
+            default:
+                if ((c2 & 0xC0) != 0x80)
+                    return static_cast<int>(frm_nxt - frm);
+                 break;
+            }
+            if ((c3 & 0xC0) != 0x80 || (c4 & 0xC0) != 0x80)
+                break;
+            if ((((c1 & 0x07u) << 18) | ((c2 & 0x3Fu) << 12) |
+                 ((c3 & 0x3Fu) << 6)  |  (c4 & 0x3Fu)) > Maxcode)
+                break;
+            frm_nxt += 4;
+        }
+        else
+        {
+            break;
+        }
+    }
+    return static_cast<int>(frm_nxt - frm);
+}
+
+static
+codecvt_base::result
+ucs2_to_utf8(const uint16_t* frm, const uint16_t* frm_end, const uint16_t*& frm_nxt,
+             uint8_t* to, uint8_t* to_end, uint8_t*& to_nxt,
+             unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & generate_header)
+    {
+        if (to_end-to_nxt < 3)
+            return codecvt_base::partial;
+        *to_nxt++ = static_cast<uint8_t>(0xEF);
+        *to_nxt++ = static_cast<uint8_t>(0xBB);
+        *to_nxt++ = static_cast<uint8_t>(0xBF);
+    }
+    for (; frm_nxt < frm_end; ++frm_nxt)
+    {
+        uint16_t wc = *frm_nxt;
+        if ((wc & 0xF800) == 0xD800 || wc > Maxcode)
+            return codecvt_base::error;
+        if (wc < 0x0080)
+        {
+            if (to_end-to_nxt < 1)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(wc);
+        }
+        else if (wc < 0x0800)
+        {
+            if (to_end-to_nxt < 2)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(0xC0 | (wc >> 6));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | (wc & 0x03F));
+        }
+        else // if (wc <= 0xFFFF)
+        {
+            if (to_end-to_nxt < 3)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(0xE0 |  (wc >> 12));
+            *to_nxt++ = static_cast<uint8_t>(0x80 | ((wc & 0x0FC0) >> 6));
+            *to_nxt++ = static_cast<uint8_t>(0x80 |  (wc & 0x003F));
+        }
+    }
+    return codecvt_base::ok;
+}
+
+static
+codecvt_base::result
+utf8_to_ucs2(const uint8_t* frm, const uint8_t* frm_end, const uint8_t*& frm_nxt,
+             uint16_t* to, uint16_t* to_end, uint16_t*& to_nxt,
+             unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 3 && frm_nxt[0] == 0xEF && frm_nxt[1] == 0xBB &&
+                                                          frm_nxt[2] == 0xBF)
+            frm_nxt += 3;
+    }
+    for (; frm_nxt < frm_end && to_nxt < to_end; ++to_nxt)
+    {
+        uint8_t c1 = static_cast<uint8_t>(*frm_nxt);
+        if (c1 < 0x80)
+        {
+            if (c1 > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = static_cast<uint16_t>(c1);
+            ++frm_nxt;
+        }
+        else if (c1 < 0xC2)
+        {
+            return codecvt_base::error;
+        }
+        else if (c1 < 0xE0)
+        {
+            if (frm_end-frm_nxt < 2)
+                return codecvt_base::partial;
+            uint8_t c2 = frm_nxt[1];
+            if ((c2 & 0xC0) != 0x80)
+                return codecvt_base::error;
+            uint16_t t = static_cast<uint16_t>(((c1 & 0x1F) << 6)
+                                              | (c2 & 0x3F));
+            if (t > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = t;
+            frm_nxt += 2;
+        }
+        else if (c1 < 0xF0)
+        {
+            if (frm_end-frm_nxt < 3)
+                return codecvt_base::partial;
+            uint8_t c2 = frm_nxt[1];
+            uint8_t c3 = frm_nxt[2];
+            switch (c1)
+            {
+            case 0xE0:
+                if ((c2 & 0xE0) != 0xA0)
+                    return codecvt_base::error;
+                 break;
+            case 0xED:
+                if ((c2 & 0xE0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            default:
+                if ((c2 & 0xC0) != 0x80)
+                    return codecvt_base::error;
+                 break;
+            }
+            if ((c3 & 0xC0) != 0x80)
+                return codecvt_base::error;
+            uint16_t t = static_cast<uint16_t>(((c1 & 0x0F) << 12)
+                                             | ((c2 & 0x3F) << 6)
+                                             |  (c3 & 0x3F));
+            if (t > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = t;
+            frm_nxt += 3;
+        }
+        else
+        {
+            return codecvt_base::error;
+        }
+    }
+    return frm_nxt < frm_end ? codecvt_base::partial : codecvt_base::ok;
+}
+
+static
+int
+utf8_to_ucs2_length(const uint8_t* frm, const uint8_t* frm_end,
+                    size_t mx, unsigned long Maxcode = 0x10FFFF,
+                    codecvt_mode mode = codecvt_mode(0))
+{
+    const uint8_t* frm_nxt = frm;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 3 && frm_nxt[0] == 0xEF && frm_nxt[1] == 0xBB &&
+                                                          frm_nxt[2] == 0xBF)
+            frm_nxt += 3;
+    }
+    for (size_t nchar32_t = 0; frm_nxt < frm_end && nchar32_t < mx; ++nchar32_t)
+    {
+        uint8_t c1 = static_cast<uint8_t>(*frm_nxt);
+        if (c1 < 0x80)
+        {
+            if (c1 > Maxcode)
+                break;
+            ++frm_nxt;
+        }
+        else if (c1 < 0xC2)
+        {
+            break;
+        }
+        else if (c1 < 0xE0)
+        {
+            if ((frm_end-frm_nxt < 2) || ((frm_nxt[1] & 0xC0) != 0x80))
+                break;
+            if ((((c1 & 0x1Fu) << 6) | (frm_nxt[1] & 0x3Fu)) > Maxcode)
+                break;
+            frm_nxt += 2;
+        }
+        else if (c1 < 0xF0)
+        {
+            if (frm_end-frm_nxt < 3)
+                break;
+            uint8_t c2 = frm_nxt[1];
+            uint8_t c3 = frm_nxt[2];
+            switch (c1)
+            {
+            case 0xE0:
+                if ((c2 & 0xE0) != 0xA0)
+                    return static_cast<int>(frm_nxt - frm);
+                break;
+            case 0xED:
+                if ((c2 & 0xE0) != 0x80)
+                    return static_cast<int>(frm_nxt - frm);
+                 break;
+            default:
+                if ((c2 & 0xC0) != 0x80)
+                    return static_cast<int>(frm_nxt - frm);
+                 break;
+            }
+            if ((c3 & 0xC0) != 0x80)
+                break;
+            if ((((c1 & 0x0Fu) << 12) | ((c2 & 0x3Fu) << 6) | (c3 & 0x3Fu)) > Maxcode)
+                break;
+            frm_nxt += 3;
+        }
+        else
+        {
+            break;
+        }
+    }
+    return static_cast<int>(frm_nxt - frm);
+}
+
+static
+codecvt_base::result
+ucs4_to_utf16be(const uint32_t* frm, const uint32_t* frm_end, const uint32_t*& frm_nxt,
+                uint8_t* to, uint8_t* to_end, uint8_t*& to_nxt,
+                unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & generate_header)
+    {
+        if (to_end-to_nxt < 2)
+            return codecvt_base::partial;
+        *to_nxt++ = static_cast<uint8_t>(0xFE);
+        *to_nxt++ = static_cast<uint8_t>(0xFF);
+    }
+    for (; frm_nxt < frm_end; ++frm_nxt)
+    {
+        uint32_t wc = *frm_nxt;
+        if ((wc & 0xFFFFF800) == 0x00D800 || wc > Maxcode)
+            return codecvt_base::error;
+        if (wc < 0x010000)
+        {
+            if (to_end-to_nxt < 2)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(wc >> 8);
+            *to_nxt++ = static_cast<uint8_t>(wc);
+        }
+        else
+        {
+            if (to_end-to_nxt < 4)
+                return codecvt_base::partial;
+            uint16_t t = static_cast<uint16_t>(
+                    0xD800
+                  | ((((wc & 0x1F0000) >> 16) - 1) << 6)
+                  |   ((wc & 0x00FC00) >> 10));
+            *to_nxt++ = static_cast<uint8_t>(t >> 8);
+            *to_nxt++ = static_cast<uint8_t>(t);
+            t = static_cast<uint16_t>(0xDC00 | (wc & 0x03FF));
+            *to_nxt++ = static_cast<uint8_t>(t >> 8);
+            *to_nxt++ = static_cast<uint8_t>(t);
+        }
+    }
+    return codecvt_base::ok;
+}
+
+static
+codecvt_base::result
+utf16be_to_ucs4(const uint8_t* frm, const uint8_t* frm_end, const uint8_t*& frm_nxt,
+                uint32_t* to, uint32_t* to_end, uint32_t*& to_nxt,
+                unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 2 && frm_nxt[0] == 0xFE && frm_nxt[1] == 0xFF)
+            frm_nxt += 2;
+    }
+    for (; frm_nxt < frm_end - 1 && to_nxt < to_end; ++to_nxt)
+    {
+        uint16_t c1 = static_cast<uint16_t>(frm_nxt[0] << 8 | frm_nxt[1]);
+        if ((c1 & 0xFC00) == 0xDC00)
+            return codecvt_base::error;
+        if ((c1 & 0xFC00) != 0xD800)
+        {
+            if (c1 > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = static_cast<uint32_t>(c1);
+            frm_nxt += 2;
+        }
+        else
+        {
+            if (frm_end-frm_nxt < 4)
+                return codecvt_base::partial;
+            uint16_t c2 = static_cast<uint16_t>(frm_nxt[2] << 8 | frm_nxt[3]);
+            if ((c2 & 0xFC00) != 0xDC00)
+                return codecvt_base::error;
+            uint32_t t = static_cast<uint32_t>(
+                    ((((c1 & 0x03C0) >> 6) + 1) << 16)
+                  |   ((c1 & 0x003F) << 10)
+                  |    (c2 & 0x03FF));
+            if (t > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = t;
+            frm_nxt += 4;
+        }
+    }
+    return frm_nxt < frm_end ? codecvt_base::partial : codecvt_base::ok;
+}
+
+static
+int
+utf16be_to_ucs4_length(const uint8_t* frm, const uint8_t* frm_end,
+                       size_t mx, unsigned long Maxcode = 0x10FFFF,
+                       codecvt_mode mode = codecvt_mode(0))
+{
+    const uint8_t* frm_nxt = frm;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 2 && frm_nxt[0] == 0xFE && frm_nxt[1] == 0xFF)
+            frm_nxt += 2;
+    }
+    for (size_t nchar32_t = 0; frm_nxt < frm_end - 1 && nchar32_t < mx; ++nchar32_t)
+    {
+        uint16_t c1 = static_cast<uint16_t>(frm_nxt[0] << 8 | frm_nxt[1]);
+        if ((c1 & 0xFC00) == 0xDC00)
+            break;
+        if ((c1 & 0xFC00) != 0xD800)
+        {
+            if (c1 > Maxcode)
+                break;
+            frm_nxt += 2;
+        }
+        else
+        {
+            if (frm_end-frm_nxt < 4)
+                break;
+            uint16_t c2 = static_cast<uint16_t>(frm_nxt[2] << 8 | frm_nxt[3]);
+            if ((c2 & 0xFC00) != 0xDC00)
+                break;
+            uint32_t t = static_cast<uint32_t>(
+                    ((((c1 & 0x03C0) >> 6) + 1) << 16)
+                  |   ((c1 & 0x003F) << 10)
+                  |    (c2 & 0x03FF));
+            if (t > Maxcode)
+                break;
+            frm_nxt += 4;
+        }
+    }
+    return static_cast<int>(frm_nxt - frm);
+}
+
+static
+codecvt_base::result
+ucs4_to_utf16le(const uint32_t* frm, const uint32_t* frm_end, const uint32_t*& frm_nxt,
+                uint8_t* to, uint8_t* to_end, uint8_t*& to_nxt,
+                unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & generate_header)
+    {
+        if (to_end - to_nxt < 2)
+            return codecvt_base::partial;
+        *to_nxt++ = static_cast<uint8_t>(0xFF);
+        *to_nxt++ = static_cast<uint8_t>(0xFE);
+    }
+    for (; frm_nxt < frm_end; ++frm_nxt)
+    {
+        uint32_t wc = *frm_nxt;
+        if ((wc & 0xFFFFF800) == 0x00D800 || wc > Maxcode)
+            return codecvt_base::error;
+        if (wc < 0x010000)
+        {
+            if (to_end-to_nxt < 2)
+                return codecvt_base::partial;
+            *to_nxt++ = static_cast<uint8_t>(wc);
+            *to_nxt++ = static_cast<uint8_t>(wc >> 8);
+        }
+        else
+        {
+            if (to_end-to_nxt < 4)
+                return codecvt_base::partial;
+            uint16_t t = static_cast<uint16_t>(
+                    0xD800
+                  | ((((wc & 0x1F0000) >> 16) - 1) << 6)
+                  |   ((wc & 0x00FC00) >> 10));
+            *to_nxt++ = static_cast<uint8_t>(t);
+            *to_nxt++ = static_cast<uint8_t>(t >> 8);
+            t = static_cast<uint16_t>(0xDC00 | (wc & 0x03FF));
+            *to_nxt++ = static_cast<uint8_t>(t);
+            *to_nxt++ = static_cast<uint8_t>(t >> 8);
+        }
+    }
+    return codecvt_base::ok;
+}
+
+static
+codecvt_base::result
+utf16le_to_ucs4(const uint8_t* frm, const uint8_t* frm_end, const uint8_t*& frm_nxt,
+                uint32_t* to, uint32_t* to_end, uint32_t*& to_nxt,
+                unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 2 && frm_nxt[0] == 0xFF && frm_nxt[1] == 0xFE)
+            frm_nxt += 2;
+    }
+    for (; frm_nxt < frm_end - 1 && to_nxt < to_end; ++to_nxt)
+    {
+        uint16_t c1 = static_cast<uint16_t>(frm_nxt[1] << 8 | frm_nxt[0]);
+        if ((c1 & 0xFC00) == 0xDC00)
+            return codecvt_base::error;
+        if ((c1 & 0xFC00) != 0xD800)
+        {
+            if (c1 > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = static_cast<uint32_t>(c1);
+            frm_nxt += 2;
+        }
+        else
+        {
+            if (frm_end-frm_nxt < 4)
+                return codecvt_base::partial;
+            uint16_t c2 = static_cast<uint16_t>(frm_nxt[3] << 8 | frm_nxt[2]);
+            if ((c2 & 0xFC00) != 0xDC00)
+                return codecvt_base::error;
+            uint32_t t = static_cast<uint32_t>(
+                    ((((c1 & 0x03C0) >> 6) + 1) << 16)
+                  |   ((c1 & 0x003F) << 10)
+                  |    (c2 & 0x03FF));
+            if (t > Maxcode)
+                return codecvt_base::error;
+            *to_nxt = t;
+            frm_nxt += 4;
+        }
+    }
+    return frm_nxt < frm_end ? codecvt_base::partial : codecvt_base::ok;
+}
+
+static
+int
+utf16le_to_ucs4_length(const uint8_t* frm, const uint8_t* frm_end,
+                       size_t mx, unsigned long Maxcode = 0x10FFFF,
+                       codecvt_mode mode = codecvt_mode(0))
+{
+    const uint8_t* frm_nxt = frm;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 2 && frm_nxt[0] == 0xFF && frm_nxt[1] == 0xFE)
+            frm_nxt += 2;
+    }
+    for (size_t nchar32_t = 0; frm_nxt < frm_end - 1 && nchar32_t < mx; ++nchar32_t)
+    {
+        uint16_t c1 = static_cast<uint16_t>(frm_nxt[1] << 8 | frm_nxt[0]);
+        if ((c1 & 0xFC00) == 0xDC00)
+            break;
+        if ((c1 & 0xFC00) != 0xD800)
+        {
+            if (c1 > Maxcode)
+                break;
+            frm_nxt += 2;
+        }
+        else
+        {
+            if (frm_end-frm_nxt < 4)
+                break;
+            uint16_t c2 = static_cast<uint16_t>(frm_nxt[3] << 8 | frm_nxt[2]);
+            if ((c2 & 0xFC00) != 0xDC00)
+                break;
+            uint32_t t = static_cast<uint32_t>(
+                    ((((c1 & 0x03C0) >> 6) + 1) << 16)
+                  |   ((c1 & 0x003F) << 10)
+                  |    (c2 & 0x03FF));
+            if (t > Maxcode)
+                break;
+            frm_nxt += 4;
+        }
+    }
+    return static_cast<int>(frm_nxt - frm);
+}
+
+static
+codecvt_base::result
+ucs2_to_utf16be(const uint16_t* frm, const uint16_t* frm_end, const uint16_t*& frm_nxt,
+                uint8_t* to, uint8_t* to_end, uint8_t*& to_nxt,
+                unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & generate_header)
+    {
+        if (to_end-to_nxt < 2)
+            return codecvt_base::partial;
+        *to_nxt++ = static_cast<uint8_t>(0xFE);
+        *to_nxt++ = static_cast<uint8_t>(0xFF);
+    }
+    for (; frm_nxt < frm_end; ++frm_nxt)
+    {
+        uint16_t wc = *frm_nxt;
+        if ((wc & 0xF800) == 0xD800 || wc > Maxcode)
+            return codecvt_base::error;
+        if (to_end-to_nxt < 2)
+            return codecvt_base::partial;
+        *to_nxt++ = static_cast<uint8_t>(wc >> 8);
+        *to_nxt++ = static_cast<uint8_t>(wc);
+    }
+    return codecvt_base::ok;
+}
+
+static
+codecvt_base::result
+utf16be_to_ucs2(const uint8_t* frm, const uint8_t* frm_end, const uint8_t*& frm_nxt,
+                uint16_t* to, uint16_t* to_end, uint16_t*& to_nxt,
+                unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 2 && frm_nxt[0] == 0xFE && frm_nxt[1] == 0xFF)
+            frm_nxt += 2;
+    }
+    for (; frm_nxt < frm_end - 1 && to_nxt < to_end; ++to_nxt)
+    {
+        uint16_t c1 = static_cast<uint16_t>(frm_nxt[0] << 8 | frm_nxt[1]);
+        if ((c1 & 0xF800) == 0xD800 || c1 > Maxcode)
+            return codecvt_base::error;
+        *to_nxt = c1;
+        frm_nxt += 2;
+    }
+    return frm_nxt < frm_end ? codecvt_base::partial : codecvt_base::ok;
+}
+
+static
+int
+utf16be_to_ucs2_length(const uint8_t* frm, const uint8_t* frm_end,
+                       size_t mx, unsigned long Maxcode = 0x10FFFF,
+                       codecvt_mode mode = codecvt_mode(0))
+{
+    const uint8_t* frm_nxt = frm;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 2 && frm_nxt[0] == 0xFE && frm_nxt[1] == 0xFF)
+            frm_nxt += 2;
+    }
+    for (size_t nchar16_t = 0; frm_nxt < frm_end - 1 && nchar16_t < mx; ++nchar16_t)
+    {
+        uint16_t c1 = static_cast<uint16_t>(frm_nxt[0] << 8 | frm_nxt[1]);
+        if ((c1 & 0xF800) == 0xD800 || c1 > Maxcode)
+            break;
+        frm_nxt += 2;
+    }
+    return static_cast<int>(frm_nxt - frm);
+}
+
+static
+codecvt_base::result
+ucs2_to_utf16le(const uint16_t* frm, const uint16_t* frm_end, const uint16_t*& frm_nxt,
+                uint8_t* to, uint8_t* to_end, uint8_t*& to_nxt,
+                unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & generate_header)
+    {
+        if (to_end-to_nxt < 2)
+            return codecvt_base::partial;
+        *to_nxt++ = static_cast<uint8_t>(0xFF);
+        *to_nxt++ = static_cast<uint8_t>(0xFE);
+    }
+    for (; frm_nxt < frm_end; ++frm_nxt)
+    {
+        uint16_t wc = *frm_nxt;
+        if ((wc & 0xF800) == 0xD800 || wc > Maxcode)
+            return codecvt_base::error;
+        if (to_end-to_nxt < 2)
+            return codecvt_base::partial;
+        *to_nxt++ = static_cast<uint8_t>(wc);
+        *to_nxt++ = static_cast<uint8_t>(wc >> 8);
+    }
+    return codecvt_base::ok;
+}
+
+static
+codecvt_base::result
+utf16le_to_ucs2(const uint8_t* frm, const uint8_t* frm_end, const uint8_t*& frm_nxt,
+                uint16_t* to, uint16_t* to_end, uint16_t*& to_nxt,
+                unsigned long Maxcode = 0x10FFFF, codecvt_mode mode = codecvt_mode(0))
+{
+    frm_nxt = frm;
+    to_nxt = to;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 2 && frm_nxt[0] == 0xFF && frm_nxt[1] == 0xFE)
+            frm_nxt += 2;
+    }
+    for (; frm_nxt < frm_end - 1 && to_nxt < to_end; ++to_nxt)
+    {
+        uint16_t c1 = static_cast<uint16_t>(frm_nxt[1] << 8 | frm_nxt[0]);
+        if ((c1 & 0xF800) == 0xD800 || c1 > Maxcode)
+            return codecvt_base::error;
+        *to_nxt = c1;
+        frm_nxt += 2;
+    }
+    return frm_nxt < frm_end ? codecvt_base::partial : codecvt_base::ok;
+}
+
+static
+int
+utf16le_to_ucs2_length(const uint8_t* frm, const uint8_t* frm_end,
+                       size_t mx, unsigned long Maxcode = 0x10FFFF,
+                       codecvt_mode mode = codecvt_mode(0))
+{
+    const uint8_t* frm_nxt = frm;
+    frm_nxt = frm;
+    if (mode & consume_header)
+    {
+        if (frm_end-frm_nxt >= 2 && frm_nxt[0] == 0xFF && frm_nxt[1] == 0xFE)
+            frm_nxt += 2;
+    }
+    for (size_t nchar16_t = 0; frm_nxt < frm_end - 1 && nchar16_t < mx; ++nchar16_t)
+    {
+        uint16_t c1 = static_cast<uint16_t>(frm_nxt[1] << 8 | frm_nxt[0]);
+        if ((c1 & 0xF800) == 0xD800 || c1 > Maxcode)
+            break;
+        frm_nxt += 2;
+    }
+    return static_cast<int>(frm_nxt - frm);
+}
+
+// template <> class codecvt<char16_t, char, mbstate_t>
+
+locale::id codecvt<char16_t, char, mbstate_t>::id;
+
+codecvt<char16_t, char, mbstate_t>::~codecvt()
+{
+}
+
+codecvt<char16_t, char, mbstate_t>::result
+codecvt<char16_t, char, mbstate_t>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+    const uint16_t* _frm = reinterpret_cast<const uint16_t*>(frm);
+    const uint16_t* _frm_end = reinterpret_cast<const uint16_t*>(frm_end);
+    const uint16_t* _frm_nxt = _frm;
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+    result r = utf16_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+codecvt<char16_t, char, mbstate_t>::result
+codecvt<char16_t, char, mbstate_t>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+    uint16_t* _to = reinterpret_cast<uint16_t*>(to);
+    uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
+    uint16_t* _to_nxt = _to;
+    result r = utf8_to_utf16(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+codecvt<char16_t, char, mbstate_t>::result
+codecvt<char16_t, char, mbstate_t>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+codecvt<char16_t, char, mbstate_t>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+codecvt<char16_t, char, mbstate_t>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+codecvt<char16_t, char, mbstate_t>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    return utf8_to_utf16_length(_frm, _frm_end, mx);
+}
+
+int
+codecvt<char16_t, char, mbstate_t>::do_max_length() const noexcept
+{
+    return 4;
+}
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+
+// template <> class codecvt<char16_t, char8_t, mbstate_t>
+
+locale::id codecvt<char16_t, char8_t, mbstate_t>::id;
+
+codecvt<char16_t, char8_t, mbstate_t>::~codecvt()
+{
+}
+
+codecvt<char16_t, char8_t, mbstate_t>::result
+codecvt<char16_t, char8_t, mbstate_t>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+    const uint16_t* _frm = reinterpret_cast<const uint16_t*>(frm);
+    const uint16_t* _frm_end = reinterpret_cast<const uint16_t*>(frm_end);
+    const uint16_t* _frm_nxt = _frm;
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+    result r = utf16_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+codecvt<char16_t, char8_t, mbstate_t>::result
+codecvt<char16_t, char8_t, mbstate_t>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+    uint16_t* _to = reinterpret_cast<uint16_t*>(to);
+    uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
+    uint16_t* _to_nxt = _to;
+    result r = utf8_to_utf16(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+codecvt<char16_t, char8_t, mbstate_t>::result
+codecvt<char16_t, char8_t, mbstate_t>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+codecvt<char16_t, char8_t, mbstate_t>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+codecvt<char16_t, char8_t, mbstate_t>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+codecvt<char16_t, char8_t, mbstate_t>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    return utf8_to_utf16_length(_frm, _frm_end, mx);
+}
+
+int
+codecvt<char16_t, char8_t, mbstate_t>::do_max_length() const noexcept
+{
+    return 4;
+}
+
+#endif
+
+// template <> class codecvt<char32_t, char, mbstate_t>
+
+locale::id codecvt<char32_t, char, mbstate_t>::id;
+
+codecvt<char32_t, char, mbstate_t>::~codecvt()
+{
+}
+
+codecvt<char32_t, char, mbstate_t>::result
+codecvt<char32_t, char, mbstate_t>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+    const uint32_t* _frm = reinterpret_cast<const uint32_t*>(frm);
+    const uint32_t* _frm_end = reinterpret_cast<const uint32_t*>(frm_end);
+    const uint32_t* _frm_nxt = _frm;
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+    result r = ucs4_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+codecvt<char32_t, char, mbstate_t>::result
+codecvt<char32_t, char, mbstate_t>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+    uint32_t* _to = reinterpret_cast<uint32_t*>(to);
+    uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
+    uint32_t* _to_nxt = _to;
+    result r = utf8_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+codecvt<char32_t, char, mbstate_t>::result
+codecvt<char32_t, char, mbstate_t>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+codecvt<char32_t, char, mbstate_t>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+codecvt<char32_t, char, mbstate_t>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+codecvt<char32_t, char, mbstate_t>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    return utf8_to_ucs4_length(_frm, _frm_end, mx);
+}
+
+int
+codecvt<char32_t, char, mbstate_t>::do_max_length() const noexcept
+{
+    return 4;
+}
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+
+// template <> class codecvt<char32_t, char8_t, mbstate_t>
+
+locale::id codecvt<char32_t, char8_t, mbstate_t>::id;
+
+codecvt<char32_t, char8_t, mbstate_t>::~codecvt()
+{
+}
+
+codecvt<char32_t, char8_t, mbstate_t>::result
+codecvt<char32_t, char8_t, mbstate_t>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+    const uint32_t* _frm = reinterpret_cast<const uint32_t*>(frm);
+    const uint32_t* _frm_end = reinterpret_cast<const uint32_t*>(frm_end);
+    const uint32_t* _frm_nxt = _frm;
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+    result r = ucs4_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+codecvt<char32_t, char8_t, mbstate_t>::result
+codecvt<char32_t, char8_t, mbstate_t>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+    uint32_t* _to = reinterpret_cast<uint32_t*>(to);
+    uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
+    uint32_t* _to_nxt = _to;
+    result r = utf8_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+codecvt<char32_t, char8_t, mbstate_t>::result
+codecvt<char32_t, char8_t, mbstate_t>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+codecvt<char32_t, char8_t, mbstate_t>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+codecvt<char32_t, char8_t, mbstate_t>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+codecvt<char32_t, char8_t, mbstate_t>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    return utf8_to_ucs4_length(_frm, _frm_end, mx);
+}
+
+int
+codecvt<char32_t, char8_t, mbstate_t>::do_max_length() const noexcept
+{
+    return 4;
+}
+
+#endif
+
+// __codecvt_utf8<wchar_t>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+__codecvt_utf8<wchar_t>::result
+__codecvt_utf8<wchar_t>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+#if defined(_LIBCPP_SHORT_WCHAR)
+    const uint16_t* _frm = reinterpret_cast<const uint16_t*>(frm);
+    const uint16_t* _frm_end = reinterpret_cast<const uint16_t*>(frm_end);
+    const uint16_t* _frm_nxt = _frm;
+#else
+    const uint32_t* _frm = reinterpret_cast<const uint32_t*>(frm);
+    const uint32_t* _frm_end = reinterpret_cast<const uint32_t*>(frm_end);
+    const uint32_t* _frm_nxt = _frm;
+#endif
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+#if defined(_LIBCPP_SHORT_WCHAR)
+    result r = ucs2_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                            _Maxcode_, _Mode_);
+#else
+    result r = ucs4_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                            _Maxcode_, _Mode_);
+#endif
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf8<wchar_t>::result
+__codecvt_utf8<wchar_t>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+#if defined(_LIBCPP_SHORT_WCHAR)
+    uint16_t* _to = reinterpret_cast<uint16_t*>(to);
+    uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
+    uint16_t* _to_nxt = _to;
+    result r = utf8_to_ucs2(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                            _Maxcode_, _Mode_);
+#else
+    uint32_t* _to = reinterpret_cast<uint32_t*>(to);
+    uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
+    uint32_t* _to_nxt = _to;
+    result r = utf8_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                            _Maxcode_, _Mode_);
+#endif
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf8<wchar_t>::result
+__codecvt_utf8<wchar_t>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+__codecvt_utf8<wchar_t>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+__codecvt_utf8<wchar_t>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+__codecvt_utf8<wchar_t>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+#if defined(_LIBCPP_SHORT_WCHAR)
+    return utf8_to_ucs2_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+#else
+    return utf8_to_ucs4_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+#endif
+}
+
+int
+__codecvt_utf8<wchar_t>::do_max_length() const noexcept
+{
+#if defined(_LIBCPP_SHORT_WCHAR)
+    if (_Mode_ & consume_header)
+        return 6;
+    return 3;
+#else
+    if (_Mode_ & consume_header)
+        return 7;
+    return 4;
+#endif
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// __codecvt_utf8<char16_t>
+
+__codecvt_utf8<char16_t>::result
+__codecvt_utf8<char16_t>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+    const uint16_t* _frm = reinterpret_cast<const uint16_t*>(frm);
+    const uint16_t* _frm_end = reinterpret_cast<const uint16_t*>(frm_end);
+    const uint16_t* _frm_nxt = _frm;
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+    result r = ucs2_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                            _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf8<char16_t>::result
+__codecvt_utf8<char16_t>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+    uint16_t* _to = reinterpret_cast<uint16_t*>(to);
+    uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
+    uint16_t* _to_nxt = _to;
+    result r = utf8_to_ucs2(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                            _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf8<char16_t>::result
+__codecvt_utf8<char16_t>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+__codecvt_utf8<char16_t>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+__codecvt_utf8<char16_t>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+__codecvt_utf8<char16_t>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    return utf8_to_ucs2_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+}
+
+int
+__codecvt_utf8<char16_t>::do_max_length() const noexcept
+{
+    if (_Mode_ & consume_header)
+        return 6;
+    return 3;
+}
+
+// __codecvt_utf8<char32_t>
+
+__codecvt_utf8<char32_t>::result
+__codecvt_utf8<char32_t>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+    const uint32_t* _frm = reinterpret_cast<const uint32_t*>(frm);
+    const uint32_t* _frm_end = reinterpret_cast<const uint32_t*>(frm_end);
+    const uint32_t* _frm_nxt = _frm;
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+    result r = ucs4_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                            _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf8<char32_t>::result
+__codecvt_utf8<char32_t>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+    uint32_t* _to = reinterpret_cast<uint32_t*>(to);
+    uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
+    uint32_t* _to_nxt = _to;
+    result r = utf8_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                            _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf8<char32_t>::result
+__codecvt_utf8<char32_t>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+__codecvt_utf8<char32_t>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+__codecvt_utf8<char32_t>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+__codecvt_utf8<char32_t>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    return utf8_to_ucs4_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+}
+
+int
+__codecvt_utf8<char32_t>::do_max_length() const noexcept
+{
+    if (_Mode_ & consume_header)
+        return 7;
+    return 4;
+}
+
+// __codecvt_utf16<wchar_t, false>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+__codecvt_utf16<wchar_t, false>::result
+__codecvt_utf16<wchar_t, false>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+#if defined(_LIBCPP_SHORT_WCHAR)
+    const uint16_t* _frm = reinterpret_cast<const uint16_t*>(frm);
+    const uint16_t* _frm_end = reinterpret_cast<const uint16_t*>(frm_end);
+    const uint16_t* _frm_nxt = _frm;
+#else
+    const uint32_t* _frm = reinterpret_cast<const uint32_t*>(frm);
+    const uint32_t* _frm_end = reinterpret_cast<const uint32_t*>(frm_end);
+    const uint32_t* _frm_nxt = _frm;
+#endif
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+#if defined(_LIBCPP_SHORT_WCHAR)
+    result r = ucs2_to_utf16be(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+#else
+    result r = ucs4_to_utf16be(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+#endif
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf16<wchar_t, false>::result
+__codecvt_utf16<wchar_t, false>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+#if defined(_LIBCPP_SHORT_WCHAR)
+    uint16_t* _to = reinterpret_cast<uint16_t*>(to);
+    uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
+    uint16_t* _to_nxt = _to;
+    result r = utf16be_to_ucs2(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+#else
+    uint32_t* _to = reinterpret_cast<uint32_t*>(to);
+    uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
+    uint32_t* _to_nxt = _to;
+    result r = utf16be_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+#endif
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf16<wchar_t, false>::result
+__codecvt_utf16<wchar_t, false>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+__codecvt_utf16<wchar_t, false>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+__codecvt_utf16<wchar_t, false>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+__codecvt_utf16<wchar_t, false>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+#if defined(_LIBCPP_SHORT_WCHAR)
+    return utf16be_to_ucs2_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+#else
+    return utf16be_to_ucs4_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+#endif
+}
+
+int
+__codecvt_utf16<wchar_t, false>::do_max_length() const noexcept
+{
+#if defined(_LIBCPP_SHORT_WCHAR)
+    if (_Mode_ & consume_header)
+        return 4;
+    return 2;
+#else
+    if (_Mode_ & consume_header)
+        return 6;
+    return 4;
+#endif
+}
+
+// __codecvt_utf16<wchar_t, true>
+
+__codecvt_utf16<wchar_t, true>::result
+__codecvt_utf16<wchar_t, true>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+#if defined(_LIBCPP_SHORT_WCHAR)
+    const uint16_t* _frm = reinterpret_cast<const uint16_t*>(frm);
+    const uint16_t* _frm_end = reinterpret_cast<const uint16_t*>(frm_end);
+    const uint16_t* _frm_nxt = _frm;
+#else
+    const uint32_t* _frm = reinterpret_cast<const uint32_t*>(frm);
+    const uint32_t* _frm_end = reinterpret_cast<const uint32_t*>(frm_end);
+    const uint32_t* _frm_nxt = _frm;
+#endif
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+#if defined(_LIBCPP_SHORT_WCHAR)
+    result r = ucs2_to_utf16le(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+#else
+    result r = ucs4_to_utf16le(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+#endif
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf16<wchar_t, true>::result
+__codecvt_utf16<wchar_t, true>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+#if defined(_LIBCPP_SHORT_WCHAR)
+    uint16_t* _to = reinterpret_cast<uint16_t*>(to);
+    uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
+    uint16_t* _to_nxt = _to;
+    result r = utf16le_to_ucs2(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+#else
+    uint32_t* _to = reinterpret_cast<uint32_t*>(to);
+    uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
+    uint32_t* _to_nxt = _to;
+    result r = utf16le_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+#endif
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf16<wchar_t, true>::result
+__codecvt_utf16<wchar_t, true>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+__codecvt_utf16<wchar_t, true>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+__codecvt_utf16<wchar_t, true>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+__codecvt_utf16<wchar_t, true>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+#if defined(_LIBCPP_SHORT_WCHAR)
+    return utf16le_to_ucs2_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+#else
+    return utf16le_to_ucs4_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+#endif
+}
+
+int
+__codecvt_utf16<wchar_t, true>::do_max_length() const noexcept
+{
+#if defined(_LIBCPP_SHORT_WCHAR)
+    if (_Mode_ & consume_header)
+        return 4;
+    return 2;
+#else
+    if (_Mode_ & consume_header)
+        return 6;
+    return 4;
+#endif
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// __codecvt_utf16<char16_t, false>
+
+__codecvt_utf16<char16_t, false>::result
+__codecvt_utf16<char16_t, false>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+    const uint16_t* _frm = reinterpret_cast<const uint16_t*>(frm);
+    const uint16_t* _frm_end = reinterpret_cast<const uint16_t*>(frm_end);
+    const uint16_t* _frm_nxt = _frm;
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+    result r = ucs2_to_utf16be(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf16<char16_t, false>::result
+__codecvt_utf16<char16_t, false>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+    uint16_t* _to = reinterpret_cast<uint16_t*>(to);
+    uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
+    uint16_t* _to_nxt = _to;
+    result r = utf16be_to_ucs2(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf16<char16_t, false>::result
+__codecvt_utf16<char16_t, false>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+__codecvt_utf16<char16_t, false>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+__codecvt_utf16<char16_t, false>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+__codecvt_utf16<char16_t, false>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    return utf16be_to_ucs2_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+}
+
+int
+__codecvt_utf16<char16_t, false>::do_max_length() const noexcept
+{
+    if (_Mode_ & consume_header)
+        return 4;
+    return 2;
+}
+
+// __codecvt_utf16<char16_t, true>
+
+__codecvt_utf16<char16_t, true>::result
+__codecvt_utf16<char16_t, true>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+    const uint16_t* _frm = reinterpret_cast<const uint16_t*>(frm);
+    const uint16_t* _frm_end = reinterpret_cast<const uint16_t*>(frm_end);
+    const uint16_t* _frm_nxt = _frm;
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+    result r = ucs2_to_utf16le(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf16<char16_t, true>::result
+__codecvt_utf16<char16_t, true>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+    uint16_t* _to = reinterpret_cast<uint16_t*>(to);
+    uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
+    uint16_t* _to_nxt = _to;
+    result r = utf16le_to_ucs2(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf16<char16_t, true>::result
+__codecvt_utf16<char16_t, true>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+__codecvt_utf16<char16_t, true>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+__codecvt_utf16<char16_t, true>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+__codecvt_utf16<char16_t, true>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    return utf16le_to_ucs2_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+}
+
+int
+__codecvt_utf16<char16_t, true>::do_max_length() const noexcept
+{
+    if (_Mode_ & consume_header)
+        return 4;
+    return 2;
+}
+
+// __codecvt_utf16<char32_t, false>
+
+__codecvt_utf16<char32_t, false>::result
+__codecvt_utf16<char32_t, false>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+    const uint32_t* _frm = reinterpret_cast<const uint32_t*>(frm);
+    const uint32_t* _frm_end = reinterpret_cast<const uint32_t*>(frm_end);
+    const uint32_t* _frm_nxt = _frm;
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+    result r = ucs4_to_utf16be(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf16<char32_t, false>::result
+__codecvt_utf16<char32_t, false>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+    uint32_t* _to = reinterpret_cast<uint32_t*>(to);
+    uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
+    uint32_t* _to_nxt = _to;
+    result r = utf16be_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf16<char32_t, false>::result
+__codecvt_utf16<char32_t, false>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+__codecvt_utf16<char32_t, false>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+__codecvt_utf16<char32_t, false>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+__codecvt_utf16<char32_t, false>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    return utf16be_to_ucs4_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+}
+
+int
+__codecvt_utf16<char32_t, false>::do_max_length() const noexcept
+{
+    if (_Mode_ & consume_header)
+        return 6;
+    return 4;
+}
+
+// __codecvt_utf16<char32_t, true>
+
+__codecvt_utf16<char32_t, true>::result
+__codecvt_utf16<char32_t, true>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+#if defined(_LIBCPP_SHORT_WCHAR)
+    const uint16_t* _frm = reinterpret_cast<const uint16_t*>(frm);
+    const uint16_t* _frm_end = reinterpret_cast<const uint16_t*>(frm_end);
+    const uint16_t* _frm_nxt = _frm;
+#else
+    const uint32_t* _frm = reinterpret_cast<const uint32_t*>(frm);
+    const uint32_t* _frm_end = reinterpret_cast<const uint32_t*>(frm_end);
+    const uint32_t* _frm_nxt = _frm;
+#endif
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+#if defined(_LIBCPP_SHORT_WCHAR)
+    result r = ucs2_to_utf16le(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+#else
+    result r = ucs4_to_utf16le(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+#endif
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf16<char32_t, true>::result
+__codecvt_utf16<char32_t, true>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+    uint32_t* _to = reinterpret_cast<uint32_t*>(to);
+    uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
+    uint32_t* _to_nxt = _to;
+    result r = utf16le_to_ucs4(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                               _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf16<char32_t, true>::result
+__codecvt_utf16<char32_t, true>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+__codecvt_utf16<char32_t, true>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+__codecvt_utf16<char32_t, true>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+__codecvt_utf16<char32_t, true>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    return utf16le_to_ucs4_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+}
+
+int
+__codecvt_utf16<char32_t, true>::do_max_length() const noexcept
+{
+    if (_Mode_ & consume_header)
+        return 6;
+    return 4;
+}
+
+// __codecvt_utf8_utf16<wchar_t>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+__codecvt_utf8_utf16<wchar_t>::result
+__codecvt_utf8_utf16<wchar_t>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+#ifdef _WIN32
+    const uint16_t* _frm = reinterpret_cast<const uint16_t*>(frm);
+    const uint16_t* _frm_end = reinterpret_cast<const uint16_t*>(frm_end);
+    const uint16_t* _frm_nxt = _frm;
+#else
+    const uint32_t* _frm = reinterpret_cast<const uint32_t*>(frm);
+    const uint32_t* _frm_end = reinterpret_cast<const uint32_t*>(frm_end);
+    const uint32_t* _frm_nxt = _frm;
+#endif
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+    result r = utf16_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                             _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf8_utf16<wchar_t>::result
+__codecvt_utf8_utf16<wchar_t>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+#ifdef _WIN32
+    uint16_t* _to = reinterpret_cast<uint16_t*>(to);
+    uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
+    uint16_t* _to_nxt = _to;
+#else
+    uint32_t* _to = reinterpret_cast<uint32_t*>(to);
+    uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
+    uint32_t* _to_nxt = _to;
+#endif
+    result r = utf8_to_utf16(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                             _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf8_utf16<wchar_t>::result
+__codecvt_utf8_utf16<wchar_t>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+__codecvt_utf8_utf16<wchar_t>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+__codecvt_utf8_utf16<wchar_t>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+__codecvt_utf8_utf16<wchar_t>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    return utf8_to_utf16_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+}
+
+int
+__codecvt_utf8_utf16<wchar_t>::do_max_length() const noexcept
+{
+    if (_Mode_ & consume_header)
+        return 7;
+    return 4;
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// __codecvt_utf8_utf16<char16_t>
+
+__codecvt_utf8_utf16<char16_t>::result
+__codecvt_utf8_utf16<char16_t>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+    const uint16_t* _frm = reinterpret_cast<const uint16_t*>(frm);
+    const uint16_t* _frm_end = reinterpret_cast<const uint16_t*>(frm_end);
+    const uint16_t* _frm_nxt = _frm;
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+    result r = utf16_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                             _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf8_utf16<char16_t>::result
+__codecvt_utf8_utf16<char16_t>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+    uint16_t* _to = reinterpret_cast<uint16_t*>(to);
+    uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
+    uint16_t* _to_nxt = _to;
+    result r = utf8_to_utf16(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                             _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf8_utf16<char16_t>::result
+__codecvt_utf8_utf16<char16_t>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+__codecvt_utf8_utf16<char16_t>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+__codecvt_utf8_utf16<char16_t>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+__codecvt_utf8_utf16<char16_t>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    return utf8_to_utf16_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+}
+
+int
+__codecvt_utf8_utf16<char16_t>::do_max_length() const noexcept
+{
+    if (_Mode_ & consume_header)
+        return 7;
+    return 4;
+}
+
+// __codecvt_utf8_utf16<char32_t>
+
+__codecvt_utf8_utf16<char32_t>::result
+__codecvt_utf8_utf16<char32_t>::do_out(state_type&,
+    const intern_type* frm, const intern_type* frm_end, const intern_type*& frm_nxt,
+    extern_type* to, extern_type* to_end, extern_type*& to_nxt) const
+{
+    const uint32_t* _frm = reinterpret_cast<const uint32_t*>(frm);
+    const uint32_t* _frm_end = reinterpret_cast<const uint32_t*>(frm_end);
+    const uint32_t* _frm_nxt = _frm;
+    uint8_t* _to = reinterpret_cast<uint8_t*>(to);
+    uint8_t* _to_end = reinterpret_cast<uint8_t*>(to_end);
+    uint8_t* _to_nxt = _to;
+    result r = utf16_to_utf8(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                             _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf8_utf16<char32_t>::result
+__codecvt_utf8_utf16<char32_t>::do_in(state_type&,
+    const extern_type* frm, const extern_type* frm_end, const extern_type*& frm_nxt,
+    intern_type* to, intern_type* to_end, intern_type*& to_nxt) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    const uint8_t* _frm_nxt = _frm;
+#if defined(_LIBCPP_SHORT_WCHAR)
+    uint16_t* _to = reinterpret_cast<uint16_t*>(to);
+    uint16_t* _to_end = reinterpret_cast<uint16_t*>(to_end);
+    uint16_t* _to_nxt = _to;
+#else
+    uint32_t* _to = reinterpret_cast<uint32_t*>(to);
+    uint32_t* _to_end = reinterpret_cast<uint32_t*>(to_end);
+    uint32_t* _to_nxt = _to;
+#endif
+    result r = utf8_to_utf16(_frm, _frm_end, _frm_nxt, _to, _to_end, _to_nxt,
+                             _Maxcode_, _Mode_);
+    frm_nxt = frm + (_frm_nxt - _frm);
+    to_nxt = to + (_to_nxt - _to);
+    return r;
+}
+
+__codecvt_utf8_utf16<char32_t>::result
+__codecvt_utf8_utf16<char32_t>::do_unshift(state_type&,
+    extern_type* to, extern_type*, extern_type*& to_nxt) const
+{
+    to_nxt = to;
+    return noconv;
+}
+
+int
+__codecvt_utf8_utf16<char32_t>::do_encoding() const noexcept
+{
+    return 0;
+}
+
+bool
+__codecvt_utf8_utf16<char32_t>::do_always_noconv() const noexcept
+{
+    return false;
+}
+
+int
+__codecvt_utf8_utf16<char32_t>::do_length(state_type&,
+    const extern_type* frm, const extern_type* frm_end, size_t mx) const
+{
+    const uint8_t* _frm = reinterpret_cast<const uint8_t*>(frm);
+    const uint8_t* _frm_end = reinterpret_cast<const uint8_t*>(frm_end);
+    return utf8_to_utf16_length(_frm, _frm_end, mx, _Maxcode_, _Mode_);
+}
+
+int
+__codecvt_utf8_utf16<char32_t>::do_max_length() const noexcept
+{
+    if (_Mode_ & consume_header)
+        return 7;
+    return 4;
+}
+
+// __narrow_to_utf8<16>
+
+__narrow_to_utf8<16>::~__narrow_to_utf8()
+{
+}
+
+// __narrow_to_utf8<32>
+
+__narrow_to_utf8<32>::~__narrow_to_utf8()
+{
+}
+
+// __widen_from_utf8<16>
+
+__widen_from_utf8<16>::~__widen_from_utf8()
+{
+}
+
+// __widen_from_utf8<32>
+
+__widen_from_utf8<32>::~__widen_from_utf8()
+{
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+static bool checked_string_to_wchar_convert(wchar_t& dest,
+                                            const char* ptr,
+                                            locale_t loc) {
+  if (*ptr == '\0')
+    return false;
+  mbstate_t mb = {};
+  wchar_t out;
+  size_t ret = __libcpp_mbrtowc_l(&out, ptr, strlen(ptr), &mb, loc);
+  if (ret == static_cast<size_t>(-1) || ret == static_cast<size_t>(-2)) {
+    return false;
+  }
+  dest = out;
+  return true;
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+static bool checked_string_to_char_convert(char& dest,
+                                           const char* ptr,
+                                           locale_t __loc) {
+  if (*ptr == '\0')
+    return false;
+  if (!ptr[1]) {
+    dest = *ptr;
+    return true;
+  }
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+  // First convert the MBS into a wide char then attempt to narrow it using
+  // wctob_l.
+  wchar_t wout;
+  if (!checked_string_to_wchar_convert(wout, ptr, __loc))
+    return false;
+  int res;
+  if ((res = __libcpp_wctob_l(wout, __loc)) != char_traits<char>::eof()) {
+    dest = res;
+    return true;
+  }
+  // FIXME: Work around specific multibyte sequences that we can reasonably
+  // translate into a different single byte.
+  switch (wout) {
+  case L'\u202F': // narrow non-breaking space
+  case L'\u00A0': // non-breaking space
+    dest = ' ';
+    return true;
+  default:
+    return false;
+  }
+#else // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+  return false;
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+  _LIBCPP_UNREACHABLE();
+}
+
+
+// numpunct<char> && numpunct<wchar_t>
+
+locale::id numpunct< char  >::id;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+locale::id numpunct<wchar_t>::id;
+#endif
+
+numpunct<char>::numpunct(size_t refs)
+    : locale::facet(refs),
+      __decimal_point_('.'),
+      __thousands_sep_(',')
+{
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+numpunct<wchar_t>::numpunct(size_t refs)
+    : locale::facet(refs),
+      __decimal_point_(L'.'),
+      __thousands_sep_(L',')
+{
+}
+#endif
+
+numpunct<char>::~numpunct()
+{
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+numpunct<wchar_t>::~numpunct()
+{
+}
+#endif
+
+ char   numpunct< char  >::do_decimal_point() const {return __decimal_point_;}
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+wchar_t numpunct<wchar_t>::do_decimal_point() const {return __decimal_point_;}
+#endif
+
+ char   numpunct< char  >::do_thousands_sep() const {return __thousands_sep_;}
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+wchar_t numpunct<wchar_t>::do_thousands_sep() const {return __thousands_sep_;}
+#endif
+
+string numpunct< char  >::do_grouping() const {return __grouping_;}
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+string numpunct<wchar_t>::do_grouping() const {return __grouping_;}
+#endif
+
+ string numpunct< char  >::do_truename() const {return "true";}
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+wstring numpunct<wchar_t>::do_truename() const {return L"true";}
+#endif
+
+ string numpunct< char  >::do_falsename() const {return "false";}
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+wstring numpunct<wchar_t>::do_falsename() const {return L"false";}
+#endif
+
+// numpunct_byname<char>
+
+numpunct_byname<char>::numpunct_byname(const char* nm, size_t refs)
+    : numpunct<char>(refs)
+{
+    __init(nm);
+}
+
+numpunct_byname<char>::numpunct_byname(const string& nm, size_t refs)
+    : numpunct<char>(refs)
+{
+    __init(nm.c_str());
+}
+
+numpunct_byname<char>::~numpunct_byname()
+{
+}
+
+void
+numpunct_byname<char>::__init(const char* nm)
+{
+    typedef numpunct<char> base;
+    if (strcmp(nm, "C") != 0)
+    {
+        __libcpp_unique_locale loc(nm);
+        if (!loc)
+            __throw_runtime_error("numpunct_byname<char>::numpunct_byname"
+                                " failed to construct for " + string(nm));
+
+        lconv* lc = __libcpp_localeconv_l(loc.get());
+        if (!checked_string_to_char_convert(__decimal_point_, lc->decimal_point,
+                                            loc.get()))
+            __decimal_point_ = base::do_decimal_point();
+        if (!checked_string_to_char_convert(__thousands_sep_, lc->thousands_sep,
+                                            loc.get()))
+            __thousands_sep_ = base::do_thousands_sep();
+        __grouping_ = lc->grouping;
+        // localization for truename and falsename is not available
+    }
+}
+
+// numpunct_byname<wchar_t>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+numpunct_byname<wchar_t>::numpunct_byname(const char* nm, size_t refs)
+    : numpunct<wchar_t>(refs)
+{
+    __init(nm);
+}
+
+numpunct_byname<wchar_t>::numpunct_byname(const string& nm, size_t refs)
+    : numpunct<wchar_t>(refs)
+{
+    __init(nm.c_str());
+}
+
+numpunct_byname<wchar_t>::~numpunct_byname()
+{
+}
+
+void
+numpunct_byname<wchar_t>::__init(const char* nm)
+{
+    if (strcmp(nm, "C") != 0)
+    {
+        __libcpp_unique_locale loc(nm);
+        if (!loc)
+            __throw_runtime_error("numpunct_byname<wchar_t>::numpunct_byname"
+                                " failed to construct for " + string(nm));
+
+        lconv* lc = __libcpp_localeconv_l(loc.get());
+        checked_string_to_wchar_convert(__decimal_point_, lc->decimal_point,
+                                        loc.get());
+        checked_string_to_wchar_convert(__thousands_sep_, lc->thousands_sep,
+                                        loc.get());
+        __grouping_ = lc->grouping;
+        // localization for truename and falsename is not available
+    }
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// num_get helpers
+
+int
+__num_get_base::__get_base(ios_base& iob)
+{
+    ios_base::fmtflags __basefield = iob.flags() & ios_base::basefield;
+    if (__basefield == ios_base::oct)
+        return 8;
+    else if (__basefield == ios_base::hex)
+        return 16;
+    else if (__basefield == 0)
+        return 0;
+    return 10;
+}
+
+const char __num_get_base::__src[33] = "0123456789abcdefABCDEFxX+-pPiInN";
+
+void
+__check_grouping(const string& __grouping, unsigned* __g, unsigned* __g_end,
+                 ios_base::iostate& __err)
+{
+//  if the grouping pattern is empty _or_ there are no grouping bits, then do nothing
+//  we always have at least a single entry in [__g, __g_end); the end of the input sequence
+	if (__grouping.size() != 0 && __g_end - __g > 1)
+    {
+        reverse(__g, __g_end);
+        const char* __ig = __grouping.data();
+        const char* __eg = __ig + __grouping.size();
+        for (unsigned* __r = __g; __r < __g_end-1; ++__r)
+        {
+            if (0 < *__ig && *__ig < numeric_limits<char>::max())
+            {
+                if (static_cast<unsigned>(*__ig) != *__r)
+                {
+                    __err = ios_base::failbit;
+                    return;
+                }
+            }
+            if (__eg - __ig > 1)
+                ++__ig;
+        }
+        if (0 < *__ig && *__ig < numeric_limits<char>::max())
+        {
+            if (static_cast<unsigned>(*__ig) < __g_end[-1] || __g_end[-1] == 0)
+                __err = ios_base::failbit;
+        }
+    }
+}
+
+void
+__num_put_base::__format_int(char* __fmtp, const char* __len, bool __signd,
+                             ios_base::fmtflags __flags)
+{
+    if ((__flags & ios_base::showpos) &&
+        (__flags & ios_base::basefield) != ios_base::oct &&
+        (__flags & ios_base::basefield) != ios_base::hex &&
+    __signd)
+        *__fmtp++ = '+';
+    if (__flags & ios_base::showbase)
+        *__fmtp++ = '#';
+    while(*__len)
+        *__fmtp++ = *__len++;
+    if ((__flags & ios_base::basefield) == ios_base::oct)
+        *__fmtp = 'o';
+    else if ((__flags & ios_base::basefield) == ios_base::hex)
+    {
+        if (__flags & ios_base::uppercase)
+            *__fmtp = 'X';
+        else
+            *__fmtp = 'x';
+    }
+    else if (__signd)
+        *__fmtp = 'd';
+    else
+        *__fmtp = 'u';
+}
+
+bool
+__num_put_base::__format_float(char* __fmtp, const char* __len,
+                               ios_base::fmtflags __flags)
+{
+    bool specify_precision = true;
+    if (__flags & ios_base::showpos)
+        *__fmtp++ = '+';
+    if (__flags & ios_base::showpoint)
+        *__fmtp++ = '#';
+    ios_base::fmtflags floatfield = __flags & ios_base::floatfield;
+    bool uppercase = (__flags & ios_base::uppercase) != 0;
+    if (floatfield == (ios_base::fixed | ios_base::scientific))
+        specify_precision = false;
+    else
+    {
+        *__fmtp++ = '.';
+        *__fmtp++ = '*';
+    }
+    while(*__len)
+        *__fmtp++ = *__len++;
+    if (floatfield == ios_base::fixed)
+    {
+        if (uppercase)
+            *__fmtp = 'F';
+        else
+            *__fmtp = 'f';
+    }
+    else if (floatfield == ios_base::scientific)
+    {
+        if (uppercase)
+            *__fmtp = 'E';
+        else
+            *__fmtp = 'e';
+    }
+    else if (floatfield == (ios_base::fixed | ios_base::scientific))
+    {
+        if (uppercase)
+            *__fmtp = 'A';
+        else
+            *__fmtp = 'a';
+    }
+    else
+    {
+        if (uppercase)
+            *__fmtp = 'G';
+        else
+            *__fmtp = 'g';
+    }
+    return specify_precision;
+}
+
+char*
+__num_put_base::__identify_padding(char* __nb, char* __ne,
+                                   const ios_base& __iob)
+{
+    switch (__iob.flags() & ios_base::adjustfield)
+    {
+    case ios_base::internal:
+        if (__nb[0] == '-' || __nb[0] == '+')
+            return __nb+1;
+        if (__ne - __nb >= 2 && __nb[0] == '0'
+                            && (__nb[1] == 'x' || __nb[1] == 'X'))
+            return __nb+2;
+        break;
+    case ios_base::left:
+        return __ne;
+    case ios_base::right:
+    default:
+        break;
+    }
+    return __nb;
+}
+
+// time_get
+
+static
+string*
+init_weeks()
+{
+    static string weeks[14];
+    weeks[0]  = "Sunday";
+    weeks[1]  = "Monday";
+    weeks[2]  = "Tuesday";
+    weeks[3]  = "Wednesday";
+    weeks[4]  = "Thursday";
+    weeks[5]  = "Friday";
+    weeks[6]  = "Saturday";
+    weeks[7]  = "Sun";
+    weeks[8]  = "Mon";
+    weeks[9]  = "Tue";
+    weeks[10] = "Wed";
+    weeks[11] = "Thu";
+    weeks[12] = "Fri";
+    weeks[13] = "Sat";
+    return weeks;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+static
+wstring*
+init_wweeks()
+{
+    static wstring weeks[14];
+    weeks[0]  = L"Sunday";
+    weeks[1]  = L"Monday";
+    weeks[2]  = L"Tuesday";
+    weeks[3]  = L"Wednesday";
+    weeks[4]  = L"Thursday";
+    weeks[5]  = L"Friday";
+    weeks[6]  = L"Saturday";
+    weeks[7]  = L"Sun";
+    weeks[8]  = L"Mon";
+    weeks[9]  = L"Tue";
+    weeks[10] = L"Wed";
+    weeks[11] = L"Thu";
+    weeks[12] = L"Fri";
+    weeks[13] = L"Sat";
+    return weeks;
+}
+#endif
+
+template <>
+const string*
+__time_get_c_storage<char>::__weeks() const
+{
+    static const string* weeks = init_weeks();
+    return weeks;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+const wstring*
+__time_get_c_storage<wchar_t>::__weeks() const
+{
+    static const wstring* weeks = init_wweeks();
+    return weeks;
+}
+#endif
+
+static
+string*
+init_months()
+{
+    static string months[24];
+    months[0]  = "January";
+    months[1]  = "February";
+    months[2]  = "March";
+    months[3]  = "April";
+    months[4]  = "May";
+    months[5]  = "June";
+    months[6]  = "July";
+    months[7]  = "August";
+    months[8]  = "September";
+    months[9]  = "October";
+    months[10] = "November";
+    months[11] = "December";
+    months[12] = "Jan";
+    months[13] = "Feb";
+    months[14] = "Mar";
+    months[15] = "Apr";
+    months[16] = "May";
+    months[17] = "Jun";
+    months[18] = "Jul";
+    months[19] = "Aug";
+    months[20] = "Sep";
+    months[21] = "Oct";
+    months[22] = "Nov";
+    months[23] = "Dec";
+    return months;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+static
+wstring*
+init_wmonths()
+{
+    static wstring months[24];
+    months[0]  = L"January";
+    months[1]  = L"February";
+    months[2]  = L"March";
+    months[3]  = L"April";
+    months[4]  = L"May";
+    months[5]  = L"June";
+    months[6]  = L"July";
+    months[7]  = L"August";
+    months[8]  = L"September";
+    months[9]  = L"October";
+    months[10] = L"November";
+    months[11] = L"December";
+    months[12] = L"Jan";
+    months[13] = L"Feb";
+    months[14] = L"Mar";
+    months[15] = L"Apr";
+    months[16] = L"May";
+    months[17] = L"Jun";
+    months[18] = L"Jul";
+    months[19] = L"Aug";
+    months[20] = L"Sep";
+    months[21] = L"Oct";
+    months[22] = L"Nov";
+    months[23] = L"Dec";
+    return months;
+}
+#endif
+
+template <>
+const string*
+__time_get_c_storage<char>::__months() const
+{
+    static const string* months = init_months();
+    return months;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+const wstring*
+__time_get_c_storage<wchar_t>::__months() const
+{
+    static const wstring* months = init_wmonths();
+    return months;
+}
+#endif
+
+static
+string*
+init_am_pm()
+{
+    static string am_pm[2];
+    am_pm[0]  = "AM";
+    am_pm[1]  = "PM";
+    return am_pm;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+static
+wstring*
+init_wam_pm()
+{
+    static wstring am_pm[2];
+    am_pm[0]  = L"AM";
+    am_pm[1]  = L"PM";
+    return am_pm;
+}
+#endif
+
+template <>
+const string*
+__time_get_c_storage<char>::__am_pm() const
+{
+    static const string* am_pm = init_am_pm();
+    return am_pm;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+const wstring*
+__time_get_c_storage<wchar_t>::__am_pm() const
+{
+    static const wstring* am_pm = init_wam_pm();
+    return am_pm;
+}
+#endif
+
+template <>
+const string&
+__time_get_c_storage<char>::__x() const
+{
+    static string s("%m/%d/%y");
+    return s;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+const wstring&
+__time_get_c_storage<wchar_t>::__x() const
+{
+    static wstring s(L"%m/%d/%y");
+    return s;
+}
+#endif
+
+template <>
+const string&
+__time_get_c_storage<char>::__X() const
+{
+    static string s("%H:%M:%S");
+    return s;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+const wstring&
+__time_get_c_storage<wchar_t>::__X() const
+{
+    static wstring s(L"%H:%M:%S");
+    return s;
+}
+#endif
+
+template <>
+const string&
+__time_get_c_storage<char>::__c() const
+{
+    static string s("%a %b %d %H:%M:%S %Y");
+    return s;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+const wstring&
+__time_get_c_storage<wchar_t>::__c() const
+{
+    static wstring s(L"%a %b %d %H:%M:%S %Y");
+    return s;
+}
+#endif
+
+template <>
+const string&
+__time_get_c_storage<char>::__r() const
+{
+    static string s("%I:%M:%S %p");
+    return s;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+const wstring&
+__time_get_c_storage<wchar_t>::__r() const
+{
+    static wstring s(L"%I:%M:%S %p");
+    return s;
+}
+#endif
+
+// time_get_byname
+
+__time_get::__time_get(const char* nm)
+    : __loc_(newlocale(LC_ALL_MASK, nm, 0))
+{
+    if (__loc_ == 0)
+        __throw_runtime_error("time_get_byname"
+                            " failed to construct for " + string(nm));
+}
+
+__time_get::__time_get(const string& nm)
+    : __loc_(newlocale(LC_ALL_MASK, nm.c_str(), 0))
+{
+    if (__loc_ == 0)
+        __throw_runtime_error("time_get_byname"
+                            " failed to construct for " + nm);
+}
+
+__time_get::~__time_get()
+{
+    freelocale(__loc_);
+}
+#if defined(__clang__)
+#pragma clang diagnostic ignored "-Wmissing-field-initializers"
+#endif
+#if defined(__GNUG__)
+#pragma GCC   diagnostic ignored "-Wmissing-field-initializers"
+#endif
+
+template <>
+string
+__time_get_storage<char>::__analyze(char fmt, const ctype<char>& ct)
+{
+    tm t = {0};
+    t.tm_sec = 59;
+    t.tm_min = 55;
+    t.tm_hour = 23;
+    t.tm_mday = 31;
+    t.tm_mon = 11;
+    t.tm_year = 161;
+    t.tm_wday = 6;
+    t.tm_yday = 364;
+    t.tm_isdst = -1;
+    char buf[100];
+    char f[3] = {0};
+    f[0] = '%';
+    f[1] = fmt;
+    size_t n = strftime_l(buf, countof(buf), f, &t, __loc_);
+    char* bb = buf;
+    char* be = buf + n;
+    string result;
+    while (bb != be)
+    {
+        if (ct.is(ctype_base::space, *bb))
+        {
+            result.push_back(' ');
+            for (++bb; bb != be && ct.is(ctype_base::space, *bb); ++bb)
+                ;
+            continue;
+        }
+        char* w = bb;
+        ios_base::iostate err = ios_base::goodbit;
+        ptrdiff_t i = __scan_keyword(w, be, this->__weeks_, this->__weeks_+14,
+                               ct, err, false)
+                               - this->__weeks_;
+        if (i < 14)
+        {
+            result.push_back('%');
+            if (i < 7)
+                result.push_back('A');
+            else
+                result.push_back('a');
+            bb = w;
+            continue;
+        }
+        w = bb;
+        i = __scan_keyword(w, be, this->__months_, this->__months_+24,
+                           ct, err, false)
+                           - this->__months_;
+        if (i < 24)
+        {
+            result.push_back('%');
+            if (i < 12)
+                result.push_back('B');
+            else
+                result.push_back('b');
+            if (fmt == 'x' && ct.is(ctype_base::digit, this->__months_[i][0]))
+                result.back() = 'm';
+            bb = w;
+            continue;
+        }
+        if (this->__am_pm_[0].size() + this->__am_pm_[1].size() > 0)
+        {
+            w = bb;
+            i = __scan_keyword(w, be, this->__am_pm_, this->__am_pm_+2,
+                               ct, err, false) - this->__am_pm_;
+            if (i < 2)
+            {
+                result.push_back('%');
+                result.push_back('p');
+                bb = w;
+                continue;
+            }
+        }
+        w = bb;
+        if (ct.is(ctype_base::digit, *bb))
+        {
+            switch(__get_up_to_n_digits(bb, be, err, ct, 4))
+            {
+            case 6:
+                result.push_back('%');
+                result.push_back('w');
+                break;
+            case 7:
+                result.push_back('%');
+                result.push_back('u');
+                break;
+            case 11:
+                result.push_back('%');
+                result.push_back('I');
+                break;
+            case 12:
+                result.push_back('%');
+                result.push_back('m');
+                break;
+            case 23:
+                result.push_back('%');
+                result.push_back('H');
+                break;
+            case 31:
+                result.push_back('%');
+                result.push_back('d');
+                break;
+            case 55:
+                result.push_back('%');
+                result.push_back('M');
+                break;
+            case 59:
+                result.push_back('%');
+                result.push_back('S');
+                break;
+            case 61:
+                result.push_back('%');
+                result.push_back('y');
+                break;
+            case 364:
+                result.push_back('%');
+                result.push_back('j');
+                break;
+            case 2061:
+                result.push_back('%');
+                result.push_back('Y');
+                break;
+            default:
+                for (; w != bb; ++w)
+                    result.push_back(*w);
+                break;
+            }
+            continue;
+        }
+        if (*bb == '%')
+        {
+            result.push_back('%');
+            result.push_back('%');
+            ++bb;
+            continue;
+        }
+        result.push_back(*bb);
+        ++bb;
+    }
+    return result;
+}
+
+#if defined(__clang__)
+#pragma clang diagnostic ignored "-Wmissing-braces"
+#endif
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+wstring
+__time_get_storage<wchar_t>::__analyze(char fmt, const ctype<wchar_t>& ct)
+{
+    tm t = {0};
+    t.tm_sec = 59;
+    t.tm_min = 55;
+    t.tm_hour = 23;
+    t.tm_mday = 31;
+    t.tm_mon = 11;
+    t.tm_year = 161;
+    t.tm_wday = 6;
+    t.tm_yday = 364;
+    t.tm_isdst = -1;
+    char buf[100];
+    char f[3] = {0};
+    f[0] = '%';
+    f[1] = fmt;
+    strftime_l(buf, countof(buf), f, &t, __loc_);
+    wchar_t wbuf[100];
+    wchar_t* wbb = wbuf;
+    mbstate_t mb = {0};
+    const char* bb = buf;
+    size_t j = __libcpp_mbsrtowcs_l( wbb, &bb, countof(wbuf), &mb, __loc_);
+    if (j == size_t(-1))
+        __throw_runtime_error("locale not supported");
+    wchar_t* wbe = wbb + j;
+    wstring result;
+    while (wbb != wbe)
+    {
+        if (ct.is(ctype_base::space, *wbb))
+        {
+            result.push_back(L' ');
+            for (++wbb; wbb != wbe && ct.is(ctype_base::space, *wbb); ++wbb)
+                ;
+            continue;
+        }
+        wchar_t* w = wbb;
+        ios_base::iostate err = ios_base::goodbit;
+        ptrdiff_t i = __scan_keyword(w, wbe, this->__weeks_, this->__weeks_+14,
+                               ct, err, false)
+                               - this->__weeks_;
+        if (i < 14)
+        {
+            result.push_back(L'%');
+            if (i < 7)
+                result.push_back(L'A');
+            else
+                result.push_back(L'a');
+            wbb = w;
+            continue;
+        }
+        w = wbb;
+        i = __scan_keyword(w, wbe, this->__months_, this->__months_+24,
+                           ct, err, false)
+                           - this->__months_;
+        if (i < 24)
+        {
+            result.push_back(L'%');
+            if (i < 12)
+                result.push_back(L'B');
+            else
+                result.push_back(L'b');
+            if (fmt == 'x' && ct.is(ctype_base::digit, this->__months_[i][0]))
+                result.back() = L'm';
+            wbb = w;
+            continue;
+        }
+        if (this->__am_pm_[0].size() + this->__am_pm_[1].size() > 0)
+        {
+            w = wbb;
+            i = __scan_keyword(w, wbe, this->__am_pm_, this->__am_pm_+2,
+                               ct, err, false) - this->__am_pm_;
+            if (i < 2)
+            {
+                result.push_back(L'%');
+                result.push_back(L'p');
+                wbb = w;
+                continue;
+            }
+        }
+        w = wbb;
+        if (ct.is(ctype_base::digit, *wbb))
+        {
+            switch(__get_up_to_n_digits(wbb, wbe, err, ct, 4))
+            {
+            case 6:
+                result.push_back(L'%');
+                result.push_back(L'w');
+                break;
+            case 7:
+                result.push_back(L'%');
+                result.push_back(L'u');
+                break;
+            case 11:
+                result.push_back(L'%');
+                result.push_back(L'I');
+                break;
+            case 12:
+                result.push_back(L'%');
+                result.push_back(L'm');
+                break;
+            case 23:
+                result.push_back(L'%');
+                result.push_back(L'H');
+                break;
+            case 31:
+                result.push_back(L'%');
+                result.push_back(L'd');
+                break;
+            case 55:
+                result.push_back(L'%');
+                result.push_back(L'M');
+                break;
+            case 59:
+                result.push_back(L'%');
+                result.push_back(L'S');
+                break;
+            case 61:
+                result.push_back(L'%');
+                result.push_back(L'y');
+                break;
+            case 364:
+                result.push_back(L'%');
+                result.push_back(L'j');
+                break;
+            case 2061:
+                result.push_back(L'%');
+                result.push_back(L'Y');
+                break;
+            default:
+                for (; w != wbb; ++w)
+                    result.push_back(*w);
+                break;
+            }
+            continue;
+        }
+        if (ct.narrow(*wbb, 0) == '%')
+        {
+            result.push_back(L'%');
+            result.push_back(L'%');
+            ++wbb;
+            continue;
+        }
+        result.push_back(*wbb);
+        ++wbb;
+    }
+    return result;
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+template <>
+void
+__time_get_storage<char>::init(const ctype<char>& ct)
+{
+    tm t = {0};
+    char buf[100];
+    // __weeks_
+    for (int i = 0; i < 7; ++i)
+    {
+        t.tm_wday = i;
+        strftime_l(buf, countof(buf), "%A", &t, __loc_);
+        __weeks_[i] = buf;
+        strftime_l(buf, countof(buf), "%a", &t, __loc_);
+        __weeks_[i+7] = buf;
+    }
+    // __months_
+    for (int i = 0; i < 12; ++i)
+    {
+        t.tm_mon = i;
+        strftime_l(buf, countof(buf), "%B", &t, __loc_);
+        __months_[i] = buf;
+        strftime_l(buf, countof(buf), "%b", &t, __loc_);
+        __months_[i+12] = buf;
+    }
+    // __am_pm_
+    t.tm_hour = 1;
+    strftime_l(buf, countof(buf), "%p", &t, __loc_);
+    __am_pm_[0] = buf;
+    t.tm_hour = 13;
+    strftime_l(buf, countof(buf), "%p", &t, __loc_);
+    __am_pm_[1] = buf;
+    __c_ = __analyze('c', ct);
+    __r_ = __analyze('r', ct);
+    __x_ = __analyze('x', ct);
+    __X_ = __analyze('X', ct);
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+void
+__time_get_storage<wchar_t>::init(const ctype<wchar_t>& ct)
+{
+    tm t = {0};
+    char buf[100];
+    wchar_t wbuf[100];
+    wchar_t* wbe;
+    mbstate_t mb = {0};
+    // __weeks_
+    for (int i = 0; i < 7; ++i)
+    {
+        t.tm_wday = i;
+        strftime_l(buf, countof(buf), "%A", &t, __loc_);
+        mb = mbstate_t();
+        const char* bb = buf;
+        size_t j = __libcpp_mbsrtowcs_l(wbuf, &bb, countof(wbuf), &mb, __loc_);
+        if (j == size_t(-1) || j == 0)
+            __throw_runtime_error("locale not supported");
+        wbe = wbuf + j;
+        __weeks_[i].assign(wbuf, wbe);
+        strftime_l(buf, countof(buf), "%a", &t, __loc_);
+        mb = mbstate_t();
+        bb = buf;
+        j = __libcpp_mbsrtowcs_l(wbuf, &bb, countof(wbuf), &mb, __loc_);
+        if (j == size_t(-1) || j == 0)
+            __throw_runtime_error("locale not supported");
+        wbe = wbuf + j;
+        __weeks_[i+7].assign(wbuf, wbe);
+    }
+    // __months_
+    for (int i = 0; i < 12; ++i)
+    {
+        t.tm_mon = i;
+        strftime_l(buf, countof(buf), "%B", &t, __loc_);
+        mb = mbstate_t();
+        const char* bb = buf;
+        size_t j = __libcpp_mbsrtowcs_l(wbuf, &bb, countof(wbuf), &mb, __loc_);
+        if (j == size_t(-1) || j == 0)
+            __throw_runtime_error("locale not supported");
+        wbe = wbuf + j;
+        __months_[i].assign(wbuf, wbe);
+        strftime_l(buf, countof(buf), "%b", &t, __loc_);
+        mb = mbstate_t();
+        bb = buf;
+        j = __libcpp_mbsrtowcs_l(wbuf, &bb, countof(wbuf), &mb, __loc_);
+        if (j == size_t(-1) || j == 0)
+            __throw_runtime_error("locale not supported");
+        wbe = wbuf + j;
+        __months_[i+12].assign(wbuf, wbe);
+    }
+    // __am_pm_
+    t.tm_hour = 1;
+    strftime_l(buf, countof(buf), "%p", &t, __loc_);
+    mb = mbstate_t();
+    const char* bb = buf;
+    size_t j = __libcpp_mbsrtowcs_l(wbuf, &bb, countof(wbuf), &mb, __loc_);
+    if (j == size_t(-1))
+        __throw_runtime_error("locale not supported");
+    wbe = wbuf + j;
+    __am_pm_[0].assign(wbuf, wbe);
+    t.tm_hour = 13;
+    strftime_l(buf, countof(buf), "%p", &t, __loc_);
+    mb = mbstate_t();
+    bb = buf;
+    j = __libcpp_mbsrtowcs_l(wbuf, &bb, countof(wbuf), &mb, __loc_);
+    if (j == size_t(-1))
+        __throw_runtime_error("locale not supported");
+    wbe = wbuf + j;
+    __am_pm_[1].assign(wbuf, wbe);
+    __c_ = __analyze('c', ct);
+    __r_ = __analyze('r', ct);
+    __x_ = __analyze('x', ct);
+    __X_ = __analyze('X', ct);
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+template <class CharT>
+struct _LIBCPP_HIDDEN __time_get_temp
+    : public ctype_byname<CharT>
+{
+    explicit __time_get_temp(const char* nm)
+        : ctype_byname<CharT>(nm, 1) {}
+    explicit __time_get_temp(const string& nm)
+        : ctype_byname<CharT>(nm, 1) {}
+};
+
+template <>
+__time_get_storage<char>::__time_get_storage(const char* __nm)
+    : __time_get(__nm)
+{
+    const __time_get_temp<char> ct(__nm);
+    init(ct);
+}
+
+template <>
+__time_get_storage<char>::__time_get_storage(const string& __nm)
+    : __time_get(__nm)
+{
+    const __time_get_temp<char> ct(__nm);
+    init(ct);
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+__time_get_storage<wchar_t>::__time_get_storage(const char* __nm)
+    : __time_get(__nm)
+{
+    const __time_get_temp<wchar_t> ct(__nm);
+    init(ct);
+}
+
+template <>
+__time_get_storage<wchar_t>::__time_get_storage(const string& __nm)
+    : __time_get(__nm)
+{
+    const __time_get_temp<wchar_t> ct(__nm);
+    init(ct);
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+template <>
+time_base::dateorder
+__time_get_storage<char>::__do_date_order() const
+{
+    unsigned i;
+    for (i = 0; i < __x_.size(); ++i)
+        if (__x_[i] == '%')
+            break;
+    ++i;
+    switch (__x_[i])
+    {
+    case 'y':
+    case 'Y':
+        for (++i; i < __x_.size(); ++i)
+            if (__x_[i] == '%')
+                break;
+        if (i == __x_.size())
+            break;
+        ++i;
+        switch (__x_[i])
+        {
+        case 'm':
+            for (++i; i < __x_.size(); ++i)
+                if (__x_[i] == '%')
+                    break;
+            if (i == __x_.size())
+                break;
+            ++i;
+            if (__x_[i] == 'd')
+                return time_base::ymd;
+            break;
+        case 'd':
+            for (++i; i < __x_.size(); ++i)
+                if (__x_[i] == '%')
+                    break;
+            if (i == __x_.size())
+                break;
+            ++i;
+            if (__x_[i] == 'm')
+                return time_base::ydm;
+            break;
+        }
+        break;
+    case 'm':
+        for (++i; i < __x_.size(); ++i)
+            if (__x_[i] == '%')
+                break;
+        if (i == __x_.size())
+            break;
+        ++i;
+        if (__x_[i] == 'd')
+        {
+            for (++i; i < __x_.size(); ++i)
+                if (__x_[i] == '%')
+                    break;
+            if (i == __x_.size())
+                break;
+            ++i;
+            if (__x_[i] == 'y' || __x_[i] == 'Y')
+                return time_base::mdy;
+            break;
+        }
+        break;
+    case 'd':
+        for (++i; i < __x_.size(); ++i)
+            if (__x_[i] == '%')
+                break;
+        if (i == __x_.size())
+            break;
+        ++i;
+        if (__x_[i] == 'm')
+        {
+            for (++i; i < __x_.size(); ++i)
+                if (__x_[i] == '%')
+                    break;
+            if (i == __x_.size())
+                break;
+            ++i;
+            if (__x_[i] == 'y' || __x_[i] == 'Y')
+                return time_base::dmy;
+            break;
+        }
+        break;
+    }
+    return time_base::no_order;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+time_base::dateorder
+__time_get_storage<wchar_t>::__do_date_order() const
+{
+    unsigned i;
+    for (i = 0; i < __x_.size(); ++i)
+        if (__x_[i] == L'%')
+            break;
+    ++i;
+    switch (__x_[i])
+    {
+    case L'y':
+    case L'Y':
+        for (++i; i < __x_.size(); ++i)
+            if (__x_[i] == L'%')
+                break;
+        if (i == __x_.size())
+            break;
+        ++i;
+        switch (__x_[i])
+        {
+        case L'm':
+            for (++i; i < __x_.size(); ++i)
+                if (__x_[i] == L'%')
+                    break;
+            if (i == __x_.size())
+                break;
+            ++i;
+            if (__x_[i] == L'd')
+                return time_base::ymd;
+            break;
+        case L'd':
+            for (++i; i < __x_.size(); ++i)
+                if (__x_[i] == L'%')
+                    break;
+            if (i == __x_.size())
+                break;
+            ++i;
+            if (__x_[i] == L'm')
+                return time_base::ydm;
+            break;
+        }
+        break;
+    case L'm':
+        for (++i; i < __x_.size(); ++i)
+            if (__x_[i] == L'%')
+                break;
+        if (i == __x_.size())
+            break;
+        ++i;
+        if (__x_[i] == L'd')
+        {
+            for (++i; i < __x_.size(); ++i)
+                if (__x_[i] == L'%')
+                    break;
+            if (i == __x_.size())
+                break;
+            ++i;
+            if (__x_[i] == L'y' || __x_[i] == L'Y')
+                return time_base::mdy;
+            break;
+        }
+        break;
+    case L'd':
+        for (++i; i < __x_.size(); ++i)
+            if (__x_[i] == L'%')
+                break;
+        if (i == __x_.size())
+            break;
+        ++i;
+        if (__x_[i] == L'm')
+        {
+            for (++i; i < __x_.size(); ++i)
+                if (__x_[i] == L'%')
+                    break;
+            if (i == __x_.size())
+                break;
+            ++i;
+            if (__x_[i] == L'y' || __x_[i] == L'Y')
+                return time_base::dmy;
+            break;
+        }
+        break;
+    }
+    return time_base::no_order;
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// time_put
+
+__time_put::__time_put(const char* nm)
+    : __loc_(newlocale(LC_ALL_MASK, nm, 0))
+{
+    if (__loc_ == 0)
+        __throw_runtime_error("time_put_byname"
+                            " failed to construct for " + string(nm));
+}
+
+__time_put::__time_put(const string& nm)
+    : __loc_(newlocale(LC_ALL_MASK, nm.c_str(), 0))
+{
+    if (__loc_ == 0)
+        __throw_runtime_error("time_put_byname"
+                            " failed to construct for " + nm);
+}
+
+__time_put::~__time_put()
+{
+    if (__loc_ != _LIBCPP_GET_C_LOCALE)
+        freelocale(__loc_);
+}
+
+void
+__time_put::__do_put(char* __nb, char*& __ne, const tm* __tm,
+                     char __fmt, char __mod) const
+{
+    char fmt[] = {'%', __fmt, __mod, 0};
+    if (__mod != 0)
+        swap(fmt[1], fmt[2]);
+    size_t n = strftime_l(__nb, countof(__nb, __ne), fmt, __tm, __loc_);
+    __ne = __nb + n;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+void
+__time_put::__do_put(wchar_t* __wb, wchar_t*& __we, const tm* __tm,
+                     char __fmt, char __mod) const
+{
+    char __nar[100];
+    char* __ne = __nar + 100;
+    __do_put(__nar, __ne, __tm, __fmt, __mod);
+    mbstate_t mb = {0};
+    const char* __nb = __nar;
+    size_t j = __libcpp_mbsrtowcs_l(__wb, &__nb, countof(__wb, __we), &mb, __loc_);
+    if (j == size_t(-1))
+        __throw_runtime_error("locale not supported");
+    __we = __wb + j;
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// moneypunct_byname
+
+template <class charT>
+static
+void
+__init_pat(money_base::pattern& pat, basic_string<charT>& __curr_symbol_,
+           bool intl, char cs_precedes, char sep_by_space, char sign_posn,
+           charT space_char)
+{
+    const char sign = static_cast<char>(money_base::sign);
+    const char space = static_cast<char>(money_base::space);
+    const char none = static_cast<char>(money_base::none);
+    const char symbol = static_cast<char>(money_base::symbol);
+    const char value = static_cast<char>(money_base::value);
+    const bool symbol_contains_sep = intl && __curr_symbol_.size() == 4;
+
+    // Comments on case branches reflect 'C11 7.11.2.1 The localeconv
+    // function'. "Space between sign and symbol or value" means that
+    // if the sign is adjacent to the symbol, there's a space between
+    // them, and otherwise there's a space between the sign and value.
+    //
+    // C11's localeconv specifies that the fourth character of an
+    // international curr_symbol is used to separate the sign and
+    // value when sep_by_space says to do so. C++ can't represent
+    // that, so we just use a space.  When sep_by_space says to
+    // separate the symbol and value-or-sign with a space, we rearrange the
+    // curr_symbol to put its spacing character on the correct side of
+    // the symbol.
+    //
+    // We also need to avoid adding an extra space between the sign
+    // and value when the currency symbol is suppressed (by not
+    // setting showbase).  We match glibc's strfmon by interpreting
+    // sep_by_space==1 as "omit the space when the currency symbol is
+    // absent".
+    //
+    // Users who want to get this right should use ICU instead.
+
+    switch (cs_precedes)
+    {
+    case 0:  // value before curr_symbol
+        if (symbol_contains_sep) {
+            // Move the separator to before the symbol, to place it
+            // between the value and symbol.
+            rotate(__curr_symbol_.begin(), __curr_symbol_.begin() + 3,
+                   __curr_symbol_.end());
+        }
+        switch (sign_posn)
+        {
+        case 0:  // Parentheses surround the quantity and currency symbol.
+            pat.field[0] = sign;
+            pat.field[1] = value;
+            pat.field[2] = none;  // Any space appears in the symbol.
+            pat.field[3] = symbol;
+            switch (sep_by_space)
+            {
+            case 0:  // No space separates the currency symbol and value.
+                // This case may have changed between C99 and C11;
+                // assume the currency symbol matches the intention.
+            case 2:  // Space between sign and currency or value.
+                // The "sign" is two parentheses, so no space here either.
+                return;
+            case 1:  // Space between currency-and-sign or currency and value.
+                if (!symbol_contains_sep) {
+                    // We insert the space into the symbol instead of
+                    // setting pat.field[2]=space so that when
+                    // showbase is not set, the space goes away too.
+                    __curr_symbol_.insert((size_t)0, 1, space_char);
+                }
+                return;
+            default:
+                break;
+            }
+            break;
+        case 1:  // The sign string precedes the quantity and currency symbol.
+            pat.field[0] = sign;
+            pat.field[3] = symbol;
+            switch (sep_by_space)
+            {
+            case 0:  // No space separates the currency symbol and value.
+                pat.field[1] = value;
+                pat.field[2] = none;
+                return;
+            case 1:  // Space between currency-and-sign or currency and value.
+                pat.field[1] = value;
+                pat.field[2] = none;
+                if (!symbol_contains_sep) {
+                    // We insert the space into the symbol instead of
+                    // setting pat.field[2]=space so that when
+                    // showbase is not set, the space goes away too.
+                    __curr_symbol_.insert((size_t)0, 1, space_char);
+                }
+                return;
+            case 2:  // Space between sign and currency or value.
+                pat.field[1] = space;
+                pat.field[2] = value;
+                if (symbol_contains_sep) {
+                    // Remove the separator from the symbol, since it
+                    // has already appeared after the sign.
+                    __curr_symbol_.erase(__curr_symbol_.begin());
+                }
+                return;
+            default:
+                break;
+            }
+            break;
+        case 2:  // The sign string succeeds the quantity and currency symbol.
+            pat.field[0] = value;
+            pat.field[3] = sign;
+            switch (sep_by_space)
+            {
+            case 0:  // No space separates the currency symbol and value.
+                pat.field[1] = none;
+                pat.field[2] = symbol;
+                return;
+            case 1:  // Space between currency-and-sign or currency and value.
+                if (!symbol_contains_sep) {
+                    // We insert the space into the symbol instead of
+                    // setting pat.field[1]=space so that when
+                    // showbase is not set, the space goes away too.
+                    __curr_symbol_.insert((size_t)0, 1, space_char);
+                }
+                pat.field[1] = none;
+                pat.field[2] = symbol;
+                return;
+            case 2:  // Space between sign and currency or value.
+                pat.field[1] = symbol;
+                pat.field[2] = space;
+                if (symbol_contains_sep) {
+                    // Remove the separator from the symbol, since it
+                    // should not be removed if showbase is absent.
+                    __curr_symbol_.erase(__curr_symbol_.begin());
+                }
+                return;
+            default:
+                break;
+            }
+            break;
+        case 3:  // The sign string immediately precedes the currency symbol.
+            pat.field[0] = value;
+            pat.field[3] = symbol;
+            switch (sep_by_space)
+            {
+            case 0:  // No space separates the currency symbol and value.
+                pat.field[1] = none;
+                pat.field[2] = sign;
+                return;
+            case 1:  // Space between currency-and-sign or currency and value.
+                pat.field[1] = space;
+                pat.field[2] = sign;
+                if (symbol_contains_sep) {
+                    // Remove the separator from the symbol, since it
+                    // has already appeared before the sign.
+                    __curr_symbol_.erase(__curr_symbol_.begin());
+                }
+                return;
+            case 2:  // Space between sign and currency or value.
+                pat.field[1] = sign;
+                pat.field[2] = none;
+                if (!symbol_contains_sep) {
+                    // We insert the space into the symbol instead of
+                    // setting pat.field[2]=space so that when
+                    // showbase is not set, the space goes away too.
+                    __curr_symbol_.insert((size_t)0, 1, space_char);
+                }
+                return;
+            default:
+                break;
+            }
+            break;
+        case 4:  // The sign string immediately succeeds the currency symbol.
+            pat.field[0] = value;
+            pat.field[3] = sign;
+            switch (sep_by_space)
+            {
+            case 0:  // No space separates the currency symbol and value.
+                pat.field[1] = none;
+                pat.field[2] = symbol;
+                return;
+            case 1:  // Space between currency-and-sign or currency and value.
+                pat.field[1] = none;
+                pat.field[2] = symbol;
+                if (!symbol_contains_sep) {
+                    // We insert the space into the symbol instead of
+                    // setting pat.field[1]=space so that when
+                    // showbase is not set, the space goes away too.
+                    __curr_symbol_.insert((size_t)0, 1, space_char);
+                }
+                return;
+            case 2:  // Space between sign and currency or value.
+                pat.field[1] = symbol;
+                pat.field[2] = space;
+                if (symbol_contains_sep) {
+                    // Remove the separator from the symbol, since it
+                    // should not disappear when showbase is absent.
+                    __curr_symbol_.erase(__curr_symbol_.begin());
+                }
+                return;
+            default:
+                break;
+            }
+            break;
+        default:
+            break;
+        }
+        break;
+    case 1:  // curr_symbol before value
+        switch (sign_posn)
+        {
+        case 0:  // Parentheses surround the quantity and currency symbol.
+            pat.field[0] = sign;
+            pat.field[1] = symbol;
+            pat.field[2] = none;  // Any space appears in the symbol.
+            pat.field[3] = value;
+            switch (sep_by_space)
+            {
+            case 0:  // No space separates the currency symbol and value.
+                // This case may have changed between C99 and C11;
+                // assume the currency symbol matches the intention.
+            case 2:  // Space between sign and currency or value.
+                // The "sign" is two parentheses, so no space here either.
+                return;
+            case 1:  // Space between currency-and-sign or currency and value.
+                if (!symbol_contains_sep) {
+                    // We insert the space into the symbol instead of
+                    // setting pat.field[2]=space so that when
+                    // showbase is not set, the space goes away too.
+                    __curr_symbol_.insert((size_t)0, 1, space_char);
+                }
+                return;
+            default:
+                break;
+            }
+            break;
+        case 1:  // The sign string precedes the quantity and currency symbol.
+            pat.field[0] = sign;
+            pat.field[3] = value;
+            switch (sep_by_space)
+            {
+            case 0:  // No space separates the currency symbol and value.
+                pat.field[1] = symbol;
+                pat.field[2] = none;
+                return;
+            case 1:  // Space between currency-and-sign or currency and value.
+                pat.field[1] = symbol;
+                pat.field[2] = none;
+                if (!symbol_contains_sep) {
+                    // We insert the space into the symbol instead of
+                    // setting pat.field[2]=space so that when
+                    // showbase is not set, the space goes away too.
+                    __curr_symbol_.push_back(space_char);
+                }
+                return;
+            case 2:  // Space between sign and currency or value.
+                pat.field[1] = space;
+                pat.field[2] = symbol;
+                if (symbol_contains_sep) {
+                    // Remove the separator from the symbol, since it
+                    // has already appeared after the sign.
+                    __curr_symbol_.pop_back();
+                }
+                return;
+            default:
+                break;
+            }
+            break;
+        case 2:  // The sign string succeeds the quantity and currency symbol.
+            pat.field[0] = symbol;
+            pat.field[3] = sign;
+            switch (sep_by_space)
+            {
+            case 0:  // No space separates the currency symbol and value.
+                pat.field[1] = none;
+                pat.field[2] = value;
+                return;
+            case 1:  // Space between currency-and-sign or currency and value.
+                pat.field[1] = none;
+                pat.field[2] = value;
+                if (!symbol_contains_sep) {
+                    // We insert the space into the symbol instead of
+                    // setting pat.field[1]=space so that when
+                    // showbase is not set, the space goes away too.
+                    __curr_symbol_.push_back(space_char);
+                }
+                return;
+            case 2:  // Space between sign and currency or value.
+                pat.field[1] = value;
+                pat.field[2] = space;
+                if (symbol_contains_sep) {
+                    // Remove the separator from the symbol, since it
+                    // will appear before the sign.
+                    __curr_symbol_.pop_back();
+                }
+                return;
+            default:
+                break;
+            }
+            break;
+        case 3:  // The sign string immediately precedes the currency symbol.
+            pat.field[0] = sign;
+            pat.field[3] = value;
+            switch (sep_by_space)
+            {
+            case 0:  // No space separates the currency symbol and value.
+                pat.field[1] = symbol;
+                pat.field[2] = none;
+                return;
+            case 1:  // Space between currency-and-sign or currency and value.
+                pat.field[1] = symbol;
+                pat.field[2] = none;
+                if (!symbol_contains_sep) {
+                    // We insert the space into the symbol instead of
+                    // setting pat.field[2]=space so that when
+                    // showbase is not set, the space goes away too.
+                    __curr_symbol_.push_back(space_char);
+                }
+                return;
+            case 2:  // Space between sign and currency or value.
+                pat.field[1] = space;
+                pat.field[2] = symbol;
+                if (symbol_contains_sep) {
+                    // Remove the separator from the symbol, since it
+                    // has already appeared after the sign.
+                    __curr_symbol_.pop_back();
+                }
+                return;
+            default:
+                break;
+            }
+            break;
+        case 4:  // The sign string immediately succeeds the currency symbol.
+            pat.field[0] = symbol;
+            pat.field[3] = value;
+            switch (sep_by_space)
+            {
+            case 0:  // No space separates the currency symbol and value.
+                pat.field[1] = sign;
+                pat.field[2] = none;
+                return;
+            case 1:  // Space between currency-and-sign or currency and value.
+                pat.field[1] = sign;
+                pat.field[2] = space;
+                if (symbol_contains_sep) {
+                    // Remove the separator from the symbol, since it
+                    // should not disappear when showbase is absent.
+                    __curr_symbol_.pop_back();
+                }
+                return;
+            case 2:  // Space between sign and currency or value.
+                pat.field[1] = none;
+                pat.field[2] = sign;
+                if (!symbol_contains_sep) {
+                    // We insert the space into the symbol instead of
+                    // setting pat.field[1]=space so that when
+                    // showbase is not set, the space goes away too.
+                    __curr_symbol_.push_back(space_char);
+                }
+                return;
+           default:
+                break;
+            }
+            break;
+        default:
+            break;
+        }
+        break;
+    default:
+        break;
+    }
+    pat.field[0] = symbol;
+    pat.field[1] = sign;
+    pat.field[2] = none;
+    pat.field[3] = value;
+}
+
+template<>
+void
+moneypunct_byname<char, false>::init(const char* nm)
+{
+    typedef moneypunct<char, false> base;
+    __libcpp_unique_locale loc(nm);
+    if (!loc)
+        __throw_runtime_error("moneypunct_byname"
+                            " failed to construct for " + string(nm));
+
+    lconv* lc = __libcpp_localeconv_l(loc.get());
+    if (!checked_string_to_char_convert(__decimal_point_,
+                                        lc->mon_decimal_point,
+                                        loc.get()))
+      __decimal_point_ = base::do_decimal_point();
+    if (!checked_string_to_char_convert(__thousands_sep_,
+                                        lc->mon_thousands_sep,
+                                        loc.get()))
+      __thousands_sep_ = base::do_thousands_sep();
+
+    __grouping_ = lc->mon_grouping;
+    __curr_symbol_ = lc->currency_symbol;
+    if (lc->frac_digits != CHAR_MAX)
+        __frac_digits_ = lc->frac_digits;
+    else
+        __frac_digits_ = base::do_frac_digits();
+    if (lc->p_sign_posn == 0)
+        __positive_sign_ = "()";
+    else
+        __positive_sign_ = lc->positive_sign;
+    if (lc->n_sign_posn == 0)
+        __negative_sign_ = "()";
+    else
+        __negative_sign_ = lc->negative_sign;
+    // Assume the positive and negative formats will want spaces in
+    // the same places in curr_symbol since there's no way to
+    // represent anything else.
+    string_type __dummy_curr_symbol = __curr_symbol_;
+    __init_pat(__pos_format_, __dummy_curr_symbol, false,
+               lc->p_cs_precedes, lc->p_sep_by_space, lc->p_sign_posn, ' ');
+    __init_pat(__neg_format_, __curr_symbol_, false,
+               lc->n_cs_precedes, lc->n_sep_by_space, lc->n_sign_posn, ' ');
+}
+
+template<>
+void
+moneypunct_byname<char, true>::init(const char* nm)
+{
+    typedef moneypunct<char, true> base;
+    __libcpp_unique_locale loc(nm);
+    if (!loc)
+        __throw_runtime_error("moneypunct_byname"
+                            " failed to construct for " + string(nm));
+
+    lconv* lc = __libcpp_localeconv_l(loc.get());
+    if (!checked_string_to_char_convert(__decimal_point_,
+                                        lc->mon_decimal_point,
+                                        loc.get()))
+      __decimal_point_ = base::do_decimal_point();
+    if (!checked_string_to_char_convert(__thousands_sep_,
+                                        lc->mon_thousands_sep,
+                                        loc.get()))
+      __thousands_sep_ = base::do_thousands_sep();
+    __grouping_ = lc->mon_grouping;
+    __curr_symbol_ = lc->int_curr_symbol;
+    if (lc->int_frac_digits != CHAR_MAX)
+        __frac_digits_ = lc->int_frac_digits;
+    else
+        __frac_digits_ = base::do_frac_digits();
+#if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
+    if (lc->p_sign_posn == 0)
+#else // _LIBCPP_MSVCRT
+    if (lc->int_p_sign_posn == 0)
+#endif // !_LIBCPP_MSVCRT
+        __positive_sign_ = "()";
+    else
+        __positive_sign_ = lc->positive_sign;
+#if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
+    if(lc->n_sign_posn == 0)
+#else // _LIBCPP_MSVCRT
+    if (lc->int_n_sign_posn == 0)
+#endif // !_LIBCPP_MSVCRT
+        __negative_sign_ = "()";
+    else
+        __negative_sign_ = lc->negative_sign;
+    // Assume the positive and negative formats will want spaces in
+    // the same places in curr_symbol since there's no way to
+    // represent anything else.
+    string_type __dummy_curr_symbol = __curr_symbol_;
+#if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
+    __init_pat(__pos_format_, __dummy_curr_symbol, true,
+               lc->p_cs_precedes, lc->p_sep_by_space, lc->p_sign_posn, ' ');
+    __init_pat(__neg_format_, __curr_symbol_, true,
+               lc->n_cs_precedes, lc->n_sep_by_space, lc->n_sign_posn, ' ');
+#else // _LIBCPP_MSVCRT
+    __init_pat(__pos_format_, __dummy_curr_symbol, true,
+               lc->int_p_cs_precedes, lc->int_p_sep_by_space,
+               lc->int_p_sign_posn, ' ');
+    __init_pat(__neg_format_, __curr_symbol_, true,
+               lc->int_n_cs_precedes, lc->int_n_sep_by_space,
+               lc->int_n_sign_posn, ' ');
+#endif // !_LIBCPP_MSVCRT
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template<>
+void
+moneypunct_byname<wchar_t, false>::init(const char* nm)
+{
+    typedef moneypunct<wchar_t, false> base;
+    __libcpp_unique_locale loc(nm);
+    if (!loc)
+        __throw_runtime_error("moneypunct_byname"
+                            " failed to construct for " + string(nm));
+    lconv* lc = __libcpp_localeconv_l(loc.get());
+    if (!checked_string_to_wchar_convert(__decimal_point_,
+                                         lc->mon_decimal_point,
+                                         loc.get()))
+      __decimal_point_ = base::do_decimal_point();
+    if (!checked_string_to_wchar_convert(__thousands_sep_,
+                                         lc->mon_thousands_sep,
+                                         loc.get()))
+      __thousands_sep_ = base::do_thousands_sep();
+    __grouping_ = lc->mon_grouping;
+    wchar_t wbuf[100];
+    mbstate_t mb = {0};
+    const char* bb = lc->currency_symbol;
+    size_t j = __libcpp_mbsrtowcs_l(wbuf, &bb, countof(wbuf), &mb, loc.get());
+    if (j == size_t(-1))
+        __throw_runtime_error("locale not supported");
+    wchar_t* wbe = wbuf + j;
+    __curr_symbol_.assign(wbuf, wbe);
+    if (lc->frac_digits != CHAR_MAX)
+        __frac_digits_ = lc->frac_digits;
+    else
+        __frac_digits_ = base::do_frac_digits();
+    if (lc->p_sign_posn == 0)
+        __positive_sign_ = L"()";
+    else
+    {
+        mb = mbstate_t();
+        bb = lc->positive_sign;
+        j = __libcpp_mbsrtowcs_l(wbuf, &bb, countof(wbuf), &mb, loc.get());
+        if (j == size_t(-1))
+            __throw_runtime_error("locale not supported");
+        wbe = wbuf + j;
+        __positive_sign_.assign(wbuf, wbe);
+    }
+    if (lc->n_sign_posn == 0)
+        __negative_sign_ = L"()";
+    else
+    {
+        mb = mbstate_t();
+        bb = lc->negative_sign;
+        j = __libcpp_mbsrtowcs_l(wbuf, &bb, countof(wbuf), &mb, loc.get());
+        if (j == size_t(-1))
+            __throw_runtime_error("locale not supported");
+        wbe = wbuf + j;
+        __negative_sign_.assign(wbuf, wbe);
+    }
+    // Assume the positive and negative formats will want spaces in
+    // the same places in curr_symbol since there's no way to
+    // represent anything else.
+    string_type __dummy_curr_symbol = __curr_symbol_;
+    __init_pat(__pos_format_, __dummy_curr_symbol, false,
+               lc->p_cs_precedes, lc->p_sep_by_space, lc->p_sign_posn, L' ');
+    __init_pat(__neg_format_, __curr_symbol_, false,
+               lc->n_cs_precedes, lc->n_sep_by_space, lc->n_sign_posn, L' ');
+}
+
+template<>
+void
+moneypunct_byname<wchar_t, true>::init(const char* nm)
+{
+    typedef moneypunct<wchar_t, true> base;
+    __libcpp_unique_locale loc(nm);
+    if (!loc)
+        __throw_runtime_error("moneypunct_byname"
+                            " failed to construct for " + string(nm));
+
+    lconv* lc = __libcpp_localeconv_l(loc.get());
+    if (!checked_string_to_wchar_convert(__decimal_point_,
+                                         lc->mon_decimal_point,
+                                         loc.get()))
+      __decimal_point_ = base::do_decimal_point();
+    if (!checked_string_to_wchar_convert(__thousands_sep_,
+                                         lc->mon_thousands_sep,
+                                         loc.get()))
+      __thousands_sep_ = base::do_thousands_sep();
+    __grouping_ = lc->mon_grouping;
+    wchar_t wbuf[100];
+    mbstate_t mb = {0};
+    const char* bb = lc->int_curr_symbol;
+    size_t j = __libcpp_mbsrtowcs_l(wbuf, &bb, countof(wbuf), &mb, loc.get());
+    if (j == size_t(-1))
+        __throw_runtime_error("locale not supported");
+    wchar_t* wbe = wbuf + j;
+    __curr_symbol_.assign(wbuf, wbe);
+    if (lc->int_frac_digits != CHAR_MAX)
+        __frac_digits_ = lc->int_frac_digits;
+    else
+        __frac_digits_ = base::do_frac_digits();
+#if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
+    if (lc->p_sign_posn == 0)
+#else // _LIBCPP_MSVCRT
+    if (lc->int_p_sign_posn == 0)
+#endif // !_LIBCPP_MSVCRT
+        __positive_sign_ = L"()";
+    else
+    {
+        mb = mbstate_t();
+        bb = lc->positive_sign;
+        j = __libcpp_mbsrtowcs_l(wbuf, &bb, countof(wbuf), &mb, loc.get());
+        if (j == size_t(-1))
+            __throw_runtime_error("locale not supported");
+        wbe = wbuf + j;
+        __positive_sign_.assign(wbuf, wbe);
+    }
+#if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
+    if (lc->n_sign_posn == 0)
+#else // _LIBCPP_MSVCRT
+    if (lc->int_n_sign_posn == 0)
+#endif // !_LIBCPP_MSVCRT
+        __negative_sign_ = L"()";
+    else
+    {
+        mb = mbstate_t();
+        bb = lc->negative_sign;
+        j = __libcpp_mbsrtowcs_l(wbuf, &bb, countof(wbuf), &mb, loc.get());
+        if (j == size_t(-1))
+            __throw_runtime_error("locale not supported");
+        wbe = wbuf + j;
+        __negative_sign_.assign(wbuf, wbe);
+    }
+    // Assume the positive and negative formats will want spaces in
+    // the same places in curr_symbol since there's no way to
+    // represent anything else.
+    string_type __dummy_curr_symbol = __curr_symbol_;
+#if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
+    __init_pat(__pos_format_, __dummy_curr_symbol, true,
+               lc->p_cs_precedes, lc->p_sep_by_space, lc->p_sign_posn, L' ');
+    __init_pat(__neg_format_, __curr_symbol_, true,
+               lc->n_cs_precedes, lc->n_sep_by_space, lc->n_sign_posn, L' ');
+#else // _LIBCPP_MSVCRT
+    __init_pat(__pos_format_, __dummy_curr_symbol, true,
+               lc->int_p_cs_precedes, lc->int_p_sep_by_space,
+               lc->int_p_sign_posn, L' ');
+    __init_pat(__neg_format_, __curr_symbol_, true,
+               lc->int_n_cs_precedes, lc->int_n_sep_by_space,
+               lc->int_n_sign_posn, L' ');
+#endif // !_LIBCPP_MSVCRT
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+void __do_nothing(void*) {}
+
+void __throw_runtime_error(const char* msg)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw runtime_error(msg);
+#else
+    (void)msg;
+    _VSTD::abort();
+#endif
+}
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS collate<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS collate<wchar_t>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS num_get<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS num_get<wchar_t>;)
+
+                           template struct _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __num_get<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template struct _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __num_get<wchar_t>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS num_put<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS num_put<wchar_t>;)
+
+                           template struct _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __num_put<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template struct _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __num_put<wchar_t>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_get<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_get<wchar_t>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_get_byname<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_get_byname<wchar_t>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_put<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_put<wchar_t>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_put_byname<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_put_byname<wchar_t>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct<char, false>;
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct<char, true>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct<wchar_t, false>;)
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct<wchar_t, true>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct_byname<char, false>;
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct_byname<char, true>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct_byname<wchar_t, false>;)
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct_byname<wchar_t, true>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS money_get<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS money_get<wchar_t>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __money_get<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __money_get<wchar_t>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS money_put<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS money_put<wchar_t>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __money_put<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __money_put<wchar_t>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS messages<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS messages<wchar_t>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS messages_byname<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS messages_byname<wchar_t>;)
+
+                           template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char, char, mbstate_t>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<wchar_t, char, mbstate_t>;)
+template class _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char16_t, char, mbstate_t>;
+template class _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char32_t, char, mbstate_t>;
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char16_t, char8_t, mbstate_t>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char32_t, char8_t, mbstate_t>;
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/memory.cpp b/contrib/libs/cxxsupp/libcxx/src/memory.cpp
new file mode 100644
index 00000000000..f9e8d448420
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/memory.cpp
@@ -0,0 +1,258 @@
+//===------------------------ memory.cpp ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "memory"
+#ifndef _LIBCPP_HAS_NO_THREADS
+#include "mutex"
+#include "thread"
+#if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
+#pragma comment(lib, "pthread")
+#endif
+#endif
+#if !defined(_LIBCPP_HAS_NO_THREADS)
+#include <atomic>
+#else
+#include "include/atomic_support.h"
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+const allocator_arg_t allocator_arg = allocator_arg_t();
+
+bad_weak_ptr::~bad_weak_ptr() noexcept {}
+
+const char*
+bad_weak_ptr::what() const noexcept
+{
+    return "bad_weak_ptr";
+}
+
+__shared_count::~__shared_count()
+{
+}
+
+__shared_weak_count::~__shared_weak_count()
+{
+}
+
+#if defined(_LIBCPP_DEPRECATED_ABI_LEGACY_LIBRARY_DEFINITIONS_FOR_INLINE_FUNCTIONS)
+void
+__shared_count::__add_shared() noexcept
+{
+#ifdef _LIBCPP_HAS_NO_THREADS
+    __libcpp_atomic_refcount_increment(__shared_owners_);
+#else
+    ++__shared_owners_;
+#endif
+}
+
+bool
+__shared_count::__release_shared() noexcept
+{
+#ifdef _LIBCPP_HAS_NO_THREADS
+    if (__libcpp_atomic_refcount_decrement(__shared_owners_) == -1)
+#else
+    if (--__shared_owners_ == -1)
+#endif
+    {
+        __on_zero_shared();
+        return true;
+    }
+    return false;
+}
+
+void
+__shared_weak_count::__add_shared() noexcept
+{
+    __shared_count::__add_shared();
+}
+
+void
+__shared_weak_count::__add_weak() noexcept
+{
+#ifdef _LIBCPP_HAS_NO_THREADS
+    __libcpp_atomic_refcount_increment(__shared_weak_owners_);
+#else
+    ++__shared_weak_owners_;
+#endif
+}
+
+void
+__shared_weak_count::__release_shared() noexcept
+{
+    if (__shared_count::__release_shared())
+        __release_weak();
+}
+
+#endif // _LIBCPP_DEPRECATED_ABI_LEGACY_LIBRARY_DEFINITIONS_FOR_INLINE_FUNCTIONS
+
+void
+__shared_weak_count::__release_weak() noexcept
+{
+    // NOTE: The acquire load here is an optimization of the very
+    // common case where a shared pointer is being destructed while
+    // having no other contended references.
+    //
+    // BENEFIT: We avoid expensive atomic stores like XADD and STREX
+    // in a common case.  Those instructions are slow and do nasty
+    // things to caches.
+    //
+    // IS THIS SAFE?  Yes.  During weak destruction, if we see that we
+    // are the last reference, we know that no-one else is accessing
+    // us. If someone were accessing us, then they would be doing so
+    // while the last shared / weak_ptr was being destructed, and
+    // that's undefined anyway.
+    //
+    // If we see anything other than a 0, then we have possible
+    // contention, and need to use an atomicrmw primitive.
+    // The same arguments don't apply for increment, where it is legal
+    // (though inadvisable) to share shared_ptr references between
+    // threads, and have them all get copied at once.  The argument
+    // also doesn't apply for __release_shared, because an outstanding
+    // weak_ptr::lock() could read / modify the shared count.
+#ifdef _LIBCPP_HAS_NO_THREADS
+    if (__libcpp_atomic_load(&__shared_weak_owners_, _AO_Acquire) == 0)
+#else
+    if (__shared_weak_owners_.load(memory_order_acquire) == 0)
+#endif
+    {
+        // no need to do this store, because we are about
+        // to destroy everything.
+        //__libcpp_atomic_store(&__shared_weak_owners_, -1, _AO_Release);
+        __on_zero_shared_weak();
+    }
+#ifdef _LIBCPP_HAS_NO_THREADS
+    else if (__libcpp_atomic_refcount_decrement(__shared_weak_owners_) == -1)
+#else
+    else if (--__shared_weak_owners_ == -1)
+#endif
+        __on_zero_shared_weak();
+}
+
+__shared_weak_count*
+__shared_weak_count::lock() noexcept
+{
+#ifdef _LIBCPP_HAS_NO_THREADS
+    long object_owners = __libcpp_atomic_load(&__shared_owners_);
+#else
+    long object_owners = __shared_owners_.load();
+#endif
+    while (object_owners != -1)
+    {
+#ifdef _LIBCPP_HAS_NO_THREADS
+        if (__libcpp_atomic_compare_exchange(&__shared_owners_,
+                                             &object_owners,
+                                             object_owners+1))
+#else
+        if (__shared_owners_.compare_exchange_weak(object_owners, object_owners+1))
+#endif
+            return this;
+    }
+    return nullptr;
+}
+
+const void*
+__shared_weak_count::__get_deleter(const type_info&) const noexcept
+{
+    return nullptr;
+}
+
+#if !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
+
+_LIBCPP_SAFE_STATIC static const std::size_t __sp_mut_count = 16;
+_LIBCPP_SAFE_STATIC static __libcpp_mutex_t mut_back[__sp_mut_count] =
+{
+    _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER,
+    _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER,
+    _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER,
+    _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER, _LIBCPP_MUTEX_INITIALIZER
+};
+
+_LIBCPP_CONSTEXPR __sp_mut::__sp_mut(void* p) noexcept
+   : __lx(p)
+{
+}
+
+void
+__sp_mut::lock() noexcept
+{
+    auto m = static_cast<__libcpp_mutex_t*>(__lx);
+    unsigned count = 0;
+    while (!__libcpp_mutex_trylock(m))
+    {
+        if (++count > 16)
+        {
+            __libcpp_mutex_lock(m);
+            break;
+        }
+        this_thread::yield();
+    }
+}
+
+void
+__sp_mut::unlock() noexcept
+{
+    __libcpp_mutex_unlock(static_cast<__libcpp_mutex_t*>(__lx));
+}
+
+__sp_mut&
+__get_sp_mut(const void* p)
+{
+    static __sp_mut muts[__sp_mut_count]
+    {
+        &mut_back[ 0], &mut_back[ 1], &mut_back[ 2], &mut_back[ 3],
+        &mut_back[ 4], &mut_back[ 5], &mut_back[ 6], &mut_back[ 7],
+        &mut_back[ 8], &mut_back[ 9], &mut_back[10], &mut_back[11],
+        &mut_back[12], &mut_back[13], &mut_back[14], &mut_back[15]
+    };
+    return muts[hash<const void*>()(p) & (__sp_mut_count-1)];
+}
+
+#endif // !defined(_LIBCPP_HAS_NO_ATOMIC_HEADER)
+
+void
+declare_reachable(void*)
+{
+}
+
+void
+declare_no_pointers(char*, size_t)
+{
+}
+
+void
+undeclare_no_pointers(char*, size_t)
+{
+}
+
+void*
+__undeclare_reachable(void* p)
+{
+    return p;
+}
+
+void*
+align(size_t alignment, size_t size, void*& ptr, size_t& space)
+{
+    void* r = nullptr;
+    if (size <= space)
+    {
+        char* p1 = static_cast<char*>(ptr);
+        char* p2 = reinterpret_cast<char*>(reinterpret_cast<size_t>(p1 + (alignment - 1)) & -alignment);
+        size_t d = static_cast<size_t>(p2 - p1);
+        if (d <= space - size)
+        {
+            r = p2;
+            ptr = r;
+            space -= d;
+        }
+    }
+    return r;
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/mutex.cpp b/contrib/libs/cxxsupp/libcxx/src/mutex.cpp
new file mode 100644
index 00000000000..124d59bc647
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/mutex.cpp
@@ -0,0 +1,279 @@
+//===------------------------- mutex.cpp ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "mutex"
+#include "limits"
+#include "system_error"
+#if !defined(_LIBCPP_ABI_MICROSOFT)
+#include "include/atomic_support.h"
+#endif
+#include "__undef_macros"
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+#if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
+#pragma comment(lib, "pthread")
+#endif
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+#ifndef _LIBCPP_HAS_NO_THREADS
+
+const defer_lock_t  defer_lock{};
+const try_to_lock_t try_to_lock{};
+const adopt_lock_t  adopt_lock{};
+
+// ~mutex is defined elsewhere
+
+void
+mutex::lock()
+{
+    int ec = __libcpp_mutex_lock(&__m_);
+    if (ec)
+        __throw_system_error(ec, "mutex lock failed");
+}
+
+bool
+mutex::try_lock() noexcept
+{
+    return __libcpp_mutex_trylock(&__m_);
+}
+
+void
+mutex::unlock() noexcept
+{
+    int ec = __libcpp_mutex_unlock(&__m_);
+    (void)ec;
+    _LIBCPP_ASSERT(ec == 0, "call to mutex::unlock failed");
+}
+
+// recursive_mutex
+
+recursive_mutex::recursive_mutex()
+{
+    int ec = __libcpp_recursive_mutex_init(&__m_);
+    if (ec)
+        __throw_system_error(ec, "recursive_mutex constructor failed");
+}
+
+recursive_mutex::~recursive_mutex()
+{
+    int e = __libcpp_recursive_mutex_destroy(&__m_);
+    (void)e;
+    _LIBCPP_ASSERT(e == 0, "call to ~recursive_mutex() failed");
+}
+
+void
+recursive_mutex::lock()
+{
+    int ec = __libcpp_recursive_mutex_lock(&__m_);
+    if (ec)
+        __throw_system_error(ec, "recursive_mutex lock failed");
+}
+
+void
+recursive_mutex::unlock() noexcept
+{
+    int e = __libcpp_recursive_mutex_unlock(&__m_);
+    (void)e;
+    _LIBCPP_ASSERT(e == 0, "call to recursive_mutex::unlock() failed");
+}
+
+bool
+recursive_mutex::try_lock() noexcept
+{
+    return __libcpp_recursive_mutex_trylock(&__m_);
+}
+
+// timed_mutex
+
+timed_mutex::timed_mutex()
+    : __locked_(false)
+{
+}
+
+timed_mutex::~timed_mutex()
+{
+    lock_guard<mutex> _(__m_);
+}
+
+void
+timed_mutex::lock()
+{
+    unique_lock<mutex> lk(__m_);
+    while (__locked_)
+        __cv_.wait(lk);
+    __locked_ = true;
+}
+
+bool
+timed_mutex::try_lock() noexcept
+{
+    unique_lock<mutex> lk(__m_, try_to_lock);
+    if (lk.owns_lock() && !__locked_)
+    {
+        __locked_ = true;
+        return true;
+    }
+    return false;
+}
+
+void
+timed_mutex::unlock() noexcept
+{
+    lock_guard<mutex> _(__m_);
+    __locked_ = false;
+    __cv_.notify_one();
+}
+
+// recursive_timed_mutex
+
+recursive_timed_mutex::recursive_timed_mutex()
+    : __count_(0),
+      __id_{}
+{
+}
+
+recursive_timed_mutex::~recursive_timed_mutex()
+{
+    lock_guard<mutex> _(__m_);
+}
+
+void
+recursive_timed_mutex::lock()
+{
+    __thread_id id = this_thread::get_id();
+    unique_lock<mutex> lk(__m_);
+    if (id ==__id_)
+    {
+        if (__count_ == numeric_limits<size_t>::max())
+            __throw_system_error(EAGAIN, "recursive_timed_mutex lock limit reached");
+        ++__count_;
+        return;
+    }
+    while (__count_ != 0)
+        __cv_.wait(lk);
+    __count_ = 1;
+    __id_ = id;
+}
+
+bool
+recursive_timed_mutex::try_lock() noexcept
+{
+    __thread_id id = this_thread::get_id();
+    unique_lock<mutex> lk(__m_, try_to_lock);
+    if (lk.owns_lock() && (__count_ == 0 || id == __id_))
+    {
+        if (__count_ == numeric_limits<size_t>::max())
+            return false;
+        ++__count_;
+        __id_ = id;
+        return true;
+    }
+    return false;
+}
+
+void
+recursive_timed_mutex::unlock() noexcept
+{
+    unique_lock<mutex> lk(__m_);
+    if (--__count_ == 0)
+    {
+        __id_.__reset();
+        lk.unlock();
+        __cv_.notify_one();
+    }
+}
+
+#endif // !_LIBCPP_HAS_NO_THREADS
+
+// If dispatch_once_f ever handles C++ exceptions, and if one can get to it
+// without illegal macros (unexpected macros not beginning with _UpperCase or
+// __lowercase), and if it stops spinning waiting threads, then call_once should
+// call into dispatch_once_f instead of here. Relevant radar this code needs to
+// keep in sync with:  7741191.
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+_LIBCPP_SAFE_STATIC static __libcpp_mutex_t mut = _LIBCPP_MUTEX_INITIALIZER;
+_LIBCPP_SAFE_STATIC static __libcpp_condvar_t cv = _LIBCPP_CONDVAR_INITIALIZER;
+#endif
+
+#ifdef _LIBCPP_ABI_MICROSOFT
+void __call_once(volatile std::atomic<once_flag::_State_type>& flag, void* arg,
+                 void (*func)(void*))
+#else
+void __call_once(volatile once_flag::_State_type& flag, void* arg,
+                 void (*func)(void*))
+#endif
+{
+#if defined(_LIBCPP_HAS_NO_THREADS)
+    if (flag == 0)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+            flag = 1;
+            func(arg);
+            flag = ~once_flag::_State_type(0);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            flag = 0;
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+#else // !_LIBCPP_HAS_NO_THREADS
+    __libcpp_mutex_lock(&mut);
+    while (flag == 1)
+        __libcpp_condvar_wait(&cv, &mut);
+    if (flag == 0)
+    {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        try
+        {
+#endif // _LIBCPP_NO_EXCEPTIONS
+#ifdef _LIBCPP_ABI_MICROSOFT
+            flag.store(once_flag::_State_type(1));
+#else
+            __libcpp_relaxed_store(&flag, once_flag::_State_type(1));
+#endif
+            __libcpp_mutex_unlock(&mut);
+            func(arg);
+            __libcpp_mutex_lock(&mut);
+#ifdef _LIBCPP_ABI_MICROSOFT
+            flag.store(~once_flag::_State_type(0), memory_order_release);
+#else
+            __libcpp_atomic_store(&flag, ~once_flag::_State_type(0),
+                                  _AO_Release);
+#endif
+            __libcpp_mutex_unlock(&mut);
+            __libcpp_condvar_broadcast(&cv);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+        }
+        catch (...)
+        {
+            __libcpp_mutex_lock(&mut);
+#ifdef _LIBCPP_ABI_MICROSOFT
+            flag.store(once_flag::_State_type(0), memory_order_relaxed);
+#else
+            __libcpp_relaxed_store(&flag, once_flag::_State_type(0));
+#endif
+            __libcpp_mutex_unlock(&mut);
+            __libcpp_condvar_broadcast(&cv);
+            throw;
+        }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    }
+    else
+        __libcpp_mutex_unlock(&mut);
+#endif // !_LIBCPP_HAS_NO_THREADS
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/mutex_destructor.cpp b/contrib/libs/cxxsupp/libcxx/src/mutex_destructor.cpp
new file mode 100644
index 00000000000..07197c3fb4c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/mutex_destructor.cpp
@@ -0,0 +1,50 @@
+//===--------------------- mutex_destructor.cpp ---------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// Define ~mutex.
+//
+// On some platforms ~mutex has been made trivial and the definition is only
+// provided for ABI compatibility.
+//
+// In order to avoid ODR violations within libc++ itself, we need to ensure
+// that *nothing* sees the non-trivial mutex declaration. For this reason
+// we re-declare the entire class in this file instead of using
+// _LIBCPP_BUILDING_LIBRARY to change the definition in the headers.
+
+#include "__config"
+#include "__threading_support"
+
+#if !defined(_LIBCPP_HAS_NO_THREADS)
+#if _LIBCPP_ABI_VERSION == 1 || !defined(_LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION)
+#define NEEDS_MUTEX_DESTRUCTOR
+#endif
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifdef NEEDS_MUTEX_DESTRUCTOR
+class _LIBCPP_TYPE_VIS mutex
+{
+    __libcpp_mutex_t __m_ = _LIBCPP_MUTEX_INITIALIZER;
+
+public:
+    _LIBCPP_ALWAYS_INLINE _LIBCPP_INLINE_VISIBILITY
+    constexpr mutex() = default;
+    mutex(const mutex&) = delete;
+    mutex& operator=(const mutex&) = delete;
+    ~mutex() noexcept;
+};
+
+
+mutex::~mutex() noexcept
+{
+    __libcpp_mutex_destroy(&__m_);
+}
+
+#endif // !_LIBCPP_HAS_NO_THREADS
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/new.cpp b/contrib/libs/cxxsupp/libcxx/src/new.cpp
new file mode 100644
index 00000000000..85afe3039e5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/new.cpp
@@ -0,0 +1,292 @@
+//===--------------------------- new.cpp ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <stdlib.h>
+
+#include "new"
+
+#if defined(_LIBCPP_ABI_MICROSOFT)
+#   if !defined(_LIBCPP_ABI_VCRUNTIME)
+#       include "support/runtime/new_handler_fallback.ipp"
+#   endif
+#elif defined(LIBCXX_BUILDING_LIBCXXABI)
+#   include <cxxabi.h>
+#elif defined(LIBCXX_BUILDING_LIBCXXRT)
+#   include <cxxabi.h>
+#   include "support/runtime/new_handler_fallback.ipp"
+#elif defined(__GLIBCXX__)
+    // nothing to do
+#else
+#   include "support/runtime/new_handler_fallback.ipp"
+#endif
+
+namespace std
+{
+
+#ifndef __GLIBCXX__
+const nothrow_t nothrow{};
+#endif
+
+#ifndef LIBSTDCXX
+
+void
+__throw_bad_alloc()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw bad_alloc();
+#else
+    _VSTD::abort();
+#endif
+}
+
+#endif // !LIBSTDCXX
+
+}  // std
+
+#if !defined(__GLIBCXX__) &&                                                   \
+    !defined(_LIBCPP_ABI_VCRUNTIME) &&      \
+    !defined(_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS)
+
+// Implement all new and delete operators as weak definitions
+// in this shared library, so that they can be overridden by programs
+// that define non-weak copies of the functions.
+
+_LIBCPP_WEAK
+void *
+operator new(std::size_t size) _THROW_BAD_ALLOC
+{
+    if (size == 0)
+        size = 1;
+    void* p;
+    while ((p = ::malloc(size)) == nullptr)
+    {
+        // If malloc fails and there is a new_handler,
+        // call it to try free up memory.
+        std::new_handler nh = std::get_new_handler();
+        if (nh)
+            nh();
+        else
+#ifndef _LIBCPP_NO_EXCEPTIONS
+            throw std::bad_alloc();
+#else
+            break;
+#endif
+    }
+    return p;
+}
+
+_LIBCPP_WEAK
+void*
+operator new(size_t size, const std::nothrow_t&) noexcept
+{
+    void* p = nullptr;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        p = ::operator new(size);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return p;
+}
+
+_LIBCPP_WEAK
+void*
+operator new[](size_t size) _THROW_BAD_ALLOC
+{
+    return ::operator new(size);
+}
+
+_LIBCPP_WEAK
+void*
+operator new[](size_t size, const std::nothrow_t&) noexcept
+{
+    void* p = nullptr;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        p = ::operator new[](size);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return p;
+}
+
+_LIBCPP_WEAK
+void
+operator delete(void* ptr) noexcept
+{
+        ::free(ptr);
+}
+
+_LIBCPP_WEAK
+void
+operator delete(void* ptr, const std::nothrow_t&) noexcept
+{
+    ::operator delete(ptr);
+}
+
+_LIBCPP_WEAK
+void
+operator delete(void* ptr, size_t) noexcept
+{
+    ::operator delete(ptr);
+}
+
+_LIBCPP_WEAK
+void
+operator delete[] (void* ptr) noexcept
+{
+    ::operator delete(ptr);
+}
+
+_LIBCPP_WEAK
+void
+operator delete[] (void* ptr, const std::nothrow_t&) noexcept
+{
+    ::operator delete[](ptr);
+}
+
+_LIBCPP_WEAK
+void
+operator delete[] (void* ptr, size_t) noexcept
+{
+    ::operator delete[](ptr);
+}
+
+#if !defined(_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION)
+
+_LIBCPP_WEAK
+void *
+operator new(std::size_t size, std::align_val_t alignment) _THROW_BAD_ALLOC
+{
+    if (size == 0)
+        size = 1;
+    if (static_cast<size_t>(alignment) < sizeof(void*))
+      alignment = std::align_val_t(sizeof(void*));
+
+    // Try allocating memory. If allocation fails and there is a new_handler,
+    // call it to try free up memory, and try again until it succeeds, or until
+    // the new_handler decides to terminate.
+    //
+    // If allocation fails and there is no new_handler, we throw bad_alloc
+    // (or return nullptr if exceptions are disabled).
+    void* p;
+    while ((p = std::__libcpp_aligned_alloc(static_cast<std::size_t>(alignment), size)) == nullptr)
+    {
+        std::new_handler nh = std::get_new_handler();
+        if (nh)
+            nh();
+        else {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+            throw std::bad_alloc();
+#else
+            break;
+#endif
+        }
+    }
+    return p;
+}
+
+_LIBCPP_WEAK
+void*
+operator new(size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept
+{
+    void* p = nullptr;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        p = ::operator new(size, alignment);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return p;
+}
+
+_LIBCPP_WEAK
+void*
+operator new[](size_t size, std::align_val_t alignment) _THROW_BAD_ALLOC
+{
+    return ::operator new(size, alignment);
+}
+
+_LIBCPP_WEAK
+void*
+operator new[](size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept
+{
+    void* p = nullptr;
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        p = ::operator new[](size, alignment);
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+    return p;
+}
+
+_LIBCPP_WEAK
+void
+operator delete(void* ptr, std::align_val_t) noexcept
+{
+        std::__libcpp_aligned_free(ptr);
+    }
+
+_LIBCPP_WEAK
+void
+operator delete(void* ptr, std::align_val_t alignment, const std::nothrow_t&) noexcept
+{
+    ::operator delete(ptr, alignment);
+}
+
+_LIBCPP_WEAK
+void
+operator delete(void* ptr, size_t, std::align_val_t alignment) noexcept
+{
+    ::operator delete(ptr, alignment);
+}
+
+_LIBCPP_WEAK
+void
+operator delete[] (void* ptr, std::align_val_t alignment) noexcept
+{
+    ::operator delete(ptr, alignment);
+}
+
+_LIBCPP_WEAK
+void
+operator delete[] (void* ptr, std::align_val_t alignment, const std::nothrow_t&) noexcept
+{
+    ::operator delete[](ptr, alignment);
+}
+
+_LIBCPP_WEAK
+void
+operator delete[] (void* ptr, size_t, std::align_val_t alignment) noexcept
+{
+    ::operator delete[](ptr, alignment);
+}
+
+#endif // !_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
+#endif // !__GLIBCXX__ && !_LIBCPP_ABI_VCRUNTIME && !_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS
diff --git a/contrib/libs/cxxsupp/libcxx/src/optional.cpp b/contrib/libs/cxxsupp/libcxx/src/optional.cpp
new file mode 100644
index 00000000000..39405bec12a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/optional.cpp
@@ -0,0 +1,42 @@
+//===------------------------ optional.cpp --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "optional"
+#include "__availability"
+
+namespace std
+{
+
+bad_optional_access::~bad_optional_access() noexcept = default;
+
+const char* bad_optional_access::what() const noexcept {
+  return "bad_optional_access";
+  }
+
+} // std
+
+
+#include <experimental/__config>
+
+//  Preserve std::experimental::bad_optional_access for ABI compatibility
+//  Even though it no longer exists in a header file
+_LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL
+
+class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS bad_optional_access
+    : public std::logic_error
+{
+public:
+	bad_optional_access() : std::logic_error("Bad optional Access") {}
+
+//	Get the key function ~bad_optional_access() into the dylib
+    virtual ~bad_optional_access() noexcept;
+};
+
+bad_optional_access::~bad_optional_access() noexcept = default;
+
+_LIBCPP_END_NAMESPACE_EXPERIMENTAL
diff --git a/contrib/libs/cxxsupp/libcxx/src/random.cpp b/contrib/libs/cxxsupp/libcxx/src/random.cpp
new file mode 100644
index 00000000000..d9833b09004
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/random.cpp
@@ -0,0 +1,199 @@
+//===-------------------------- random.cpp --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <__config>
+
+#if defined(_LIBCPP_USING_WIN32_RANDOM)
+// Must be defined before including stdlib.h to enable rand_s().
+#define _CRT_RAND_S
+#endif // defined(_LIBCPP_USING_WIN32_RANDOM)
+
+#include "limits"
+#include "random"
+#include "system_error"
+
+#if defined(__sun__)
+#define rename solaris_headers_are_broken
+#endif // defined(__sun__)
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#if defined(_LIBCPP_USING_GETENTROPY)
+#include <sys/random.h>
+#elif defined(_LIBCPP_USING_DEV_RANDOM)
+#include <fcntl.h>
+#include <unistd.h>
+#if __has_include(<sys/ioctl.h>) && __has_include(<linux/random.h>)
+#include <sys/ioctl.h>
+#include <linux/random.h>
+#endif
+#elif defined(_LIBCPP_USING_NACL_RANDOM)
+#include <nacl/nacl_random.h>
+#endif
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if defined(_LIBCPP_USING_GETENTROPY)
+
+random_device::random_device(const string& __token)
+{
+    if (__token != "/dev/urandom")
+        __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
+}
+
+random_device::~random_device()
+{
+}
+
+unsigned
+random_device::operator()()
+{
+    unsigned r;
+    size_t n = sizeof(r);
+    int err = getentropy(&r, n);
+    if (err)
+        __throw_system_error(errno, "random_device getentropy failed");
+    return r;
+}
+
+#elif defined(_LIBCPP_USING_ARC4_RANDOM)
+
+random_device::random_device(const string& __token)
+{
+    if (__token != "/dev/urandom")
+        __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
+}
+
+random_device::~random_device()
+{
+}
+
+unsigned
+random_device::operator()()
+{
+    return arc4random();
+}
+
+#elif defined(_LIBCPP_USING_DEV_RANDOM)
+
+random_device::random_device(const string& __token)
+    : __f_(open(__token.c_str(), O_RDONLY))
+{
+    if (__f_ < 0)
+        __throw_system_error(errno, ("random_device failed to open " + __token).c_str());
+}
+
+random_device::~random_device()
+{
+    close(__f_);
+}
+
+unsigned
+random_device::operator()()
+{
+    unsigned r;
+    size_t n = sizeof(r);
+    char* p = reinterpret_cast<char*>(&r);
+    while (n > 0)
+    {
+        ssize_t s = read(__f_, p, n);
+        if (s == 0)
+            __throw_system_error(ENODATA, "random_device got EOF");
+        if (s == -1)
+        {
+            if (errno != EINTR)
+                __throw_system_error(errno, "random_device got an unexpected error");
+            continue;
+        }
+        n -= static_cast<size_t>(s);
+        p += static_cast<size_t>(s);
+    }
+    return r;
+}
+
+#elif defined(_LIBCPP_USING_NACL_RANDOM)
+
+random_device::random_device(const string& __token)
+{
+    if (__token != "/dev/urandom")
+        __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
+    int error = nacl_secure_random_init();
+    if (error)
+        __throw_system_error(error, ("random device failed to open " + __token).c_str());
+}
+
+random_device::~random_device()
+{
+}
+
+unsigned
+random_device::operator()()
+{
+    unsigned r;
+    size_t n = sizeof(r);
+    size_t bytes_written;
+    int error = nacl_secure_random(&r, n, &bytes_written);
+    if (error != 0)
+        __throw_system_error(error, "random_device failed getting bytes");
+    else if (bytes_written != n)
+        __throw_runtime_error("random_device failed to obtain enough bytes");
+    return r;
+}
+
+#elif defined(_LIBCPP_USING_WIN32_RANDOM)
+
+random_device::random_device(const string& __token)
+{
+    if (__token != "/dev/urandom")
+        __throw_system_error(ENOENT, ("random device not supported " + __token).c_str());
+}
+
+random_device::~random_device()
+{
+}
+
+unsigned
+random_device::operator()()
+{
+    unsigned r;
+    errno_t err = rand_s(&r);
+    if (err)
+        __throw_system_error(err, "random_device rand_s failed.");
+    return r;
+}
+
+#else
+#error "Random device not implemented for this architecture"
+#endif
+
+double
+random_device::entropy() const noexcept
+{
+#if defined(_LIBCPP_USING_DEV_RANDOM) && defined(RNDGETENTCNT)
+  int ent;
+  if (::ioctl(__f_, RNDGETENTCNT, &ent) < 0)
+    return 0;
+
+  if (ent < 0)
+    return 0;
+
+  if (ent > std::numeric_limits<result_type>::digits)
+    return std::numeric_limits<result_type>::digits;
+
+  return ent;
+#elif defined(__OpenBSD__)
+  return std::numeric_limits<result_type>::digits;
+#else
+    return 0;
+#endif
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/random_shuffle.cpp b/contrib/libs/cxxsupp/libcxx/src/random_shuffle.cpp
new file mode 100644
index 00000000000..be2c47fa0de
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/random_shuffle.cpp
@@ -0,0 +1,61 @@
+//===----------------------- random_shuffle.cpp ---------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "algorithm"
+#include "random"
+#ifndef _LIBCPP_HAS_NO_THREADS
+#   include "mutex"
+#   if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
+#       pragma comment(lib, "pthread")
+#   endif
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_HAS_NO_THREADS
+_LIBCPP_SAFE_STATIC static __libcpp_mutex_t __rs_mut = _LIBCPP_MUTEX_INITIALIZER;
+#endif
+unsigned __rs_default::__c_ = 0;
+
+__rs_default::__rs_default()
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    __libcpp_mutex_lock(&__rs_mut);
+#endif
+    __c_ = 1;
+}
+
+__rs_default::__rs_default(const __rs_default&)
+{
+    ++__c_;
+}
+
+__rs_default::~__rs_default()
+{
+#ifndef _LIBCPP_HAS_NO_THREADS
+    if (--__c_ == 0)
+       __libcpp_mutex_unlock(&__rs_mut);
+#else
+    --__c_;
+#endif
+}
+
+__rs_default::result_type
+__rs_default::operator()()
+{
+    static mt19937 __rs_g;
+    return __rs_g();
+}
+
+__rs_default
+__rs_get()
+{
+    return __rs_default();
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/regex.cpp b/contrib/libs/cxxsupp/libcxx/src/regex.cpp
new file mode 100644
index 00000000000..d31e4948743
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/regex.cpp
@@ -0,0 +1,316 @@
+//===-------------------------- regex.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "regex"
+#include "algorithm"
+#include "iterator"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+static
+const char*
+make_error_type_string(regex_constants::error_type ecode)
+{
+    switch (ecode)
+    {
+    case regex_constants::error_collate:
+        return "The expression contained an invalid collating element name.";
+    case regex_constants::error_ctype:
+        return "The expression contained an invalid character class name.";
+    case regex_constants::error_escape:
+        return "The expression contained an invalid escaped character, or a "
+               "trailing escape.";
+    case regex_constants::error_backref:
+        return "The expression contained an invalid back reference.";
+    case regex_constants::error_brack:
+        return "The expression contained mismatched [ and ].";
+    case regex_constants::error_paren:
+        return "The expression contained mismatched ( and ).";
+    case regex_constants::error_brace:
+        return "The expression contained mismatched { and }.";
+    case regex_constants::error_badbrace:
+        return "The expression contained an invalid range in a {} expression.";
+    case regex_constants::error_range:
+        return "The expression contained an invalid character range, "
+               "such as [b-a] in most encodings.";
+    case regex_constants::error_space:
+        return "There was insufficient memory to convert the expression into "
+               "a finite state machine.";
+    case regex_constants::error_badrepeat:
+        return "One of *?+{ was not preceded by a valid regular expression.";
+    case regex_constants::error_complexity:
+        return "The complexity of an attempted match against a regular "
+               "expression exceeded a pre-set level.";
+    case regex_constants::error_stack:
+        return "There was insufficient memory to determine whether the regular "
+               "expression could match the specified character sequence.";
+    case regex_constants::__re_err_grammar:
+        return "An invalid regex grammar has been requested.";
+    case regex_constants::__re_err_empty:
+        return "An empty regex is not allowed in the POSIX grammar.";
+    case regex_constants::__re_err_parse:
+        return "The parser did not consume the entire regular expression.";
+    default:
+        break;
+    }
+    return "Unknown error type";
+}
+
+regex_error::regex_error(regex_constants::error_type ecode)
+    : runtime_error(make_error_type_string(ecode)),
+      __code_(ecode)
+{}
+
+regex_error::~regex_error() throw() {}
+
+namespace {
+
+struct collationnames
+{
+    const char* elem_;
+    char char_;
+};
+
+const collationnames collatenames[] =
+{
+    {"A", 0x41},
+    {"B", 0x42},
+    {"C", 0x43},
+    {"D", 0x44},
+    {"E", 0x45},
+    {"F", 0x46},
+    {"G", 0x47},
+    {"H", 0x48},
+    {"I", 0x49},
+    {"J", 0x4a},
+    {"K", 0x4b},
+    {"L", 0x4c},
+    {"M", 0x4d},
+    {"N", 0x4e},
+    {"NUL", 0x00},
+    {"O", 0x4f},
+    {"P", 0x50},
+    {"Q", 0x51},
+    {"R", 0x52},
+    {"S", 0x53},
+    {"T", 0x54},
+    {"U", 0x55},
+    {"V", 0x56},
+    {"W", 0x57},
+    {"X", 0x58},
+    {"Y", 0x59},
+    {"Z", 0x5a},
+    {"a", 0x61},
+    {"alert", 0x07},
+    {"ampersand", 0x26},
+    {"apostrophe", 0x27},
+    {"asterisk", 0x2a},
+    {"b", 0x62},
+    {"backslash", 0x5c},
+    {"backspace", 0x08},
+    {"c", 0x63},
+    {"carriage-return", 0x0d},
+    {"circumflex", 0x5e},
+    {"circumflex-accent", 0x5e},
+    {"colon", 0x3a},
+    {"comma", 0x2c},
+    {"commercial-at", 0x40},
+    {"d", 0x64},
+    {"dollar-sign", 0x24},
+    {"e", 0x65},
+    {"eight", 0x38},
+    {"equals-sign", 0x3d},
+    {"exclamation-mark", 0x21},
+    {"f", 0x66},
+    {"five", 0x35},
+    {"form-feed", 0x0c},
+    {"four", 0x34},
+    {"full-stop", 0x2e},
+    {"g", 0x67},
+    {"grave-accent", 0x60},
+    {"greater-than-sign", 0x3e},
+    {"h", 0x68},
+    {"hyphen", 0x2d},
+    {"hyphen-minus", 0x2d},
+    {"i", 0x69},
+    {"j", 0x6a},
+    {"k", 0x6b},
+    {"l", 0x6c},
+    {"left-brace", 0x7b},
+    {"left-curly-bracket", 0x7b},
+    {"left-parenthesis", 0x28},
+    {"left-square-bracket", 0x5b},
+    {"less-than-sign", 0x3c},
+    {"low-line", 0x5f},
+    {"m", 0x6d},
+    {"n", 0x6e},
+    {"newline", 0x0a},
+    {"nine", 0x39},
+    {"number-sign", 0x23},
+    {"o", 0x6f},
+    {"one", 0x31},
+    {"p", 0x70},
+    {"percent-sign", 0x25},
+    {"period", 0x2e},
+    {"plus-sign", 0x2b},
+    {"q", 0x71},
+    {"question-mark", 0x3f},
+    {"quotation-mark", 0x22},
+    {"r", 0x72},
+    {"reverse-solidus", 0x5c},
+    {"right-brace", 0x7d},
+    {"right-curly-bracket", 0x7d},
+    {"right-parenthesis", 0x29},
+    {"right-square-bracket", 0x5d},
+    {"s", 0x73},
+    {"semicolon", 0x3b},
+    {"seven", 0x37},
+    {"six", 0x36},
+    {"slash", 0x2f},
+    {"solidus", 0x2f},
+    {"space", 0x20},
+    {"t", 0x74},
+    {"tab", 0x09},
+    {"three", 0x33},
+    {"tilde", 0x7e},
+    {"two", 0x32},
+    {"u", 0x75},
+    {"underscore", 0x5f},
+    {"v", 0x76},
+    {"vertical-line", 0x7c},
+    {"vertical-tab", 0x0b},
+    {"w", 0x77},
+    {"x", 0x78},
+    {"y", 0x79},
+    {"z", 0x7a},
+    {"zero", 0x30}
+};
+
+struct classnames
+{
+    const char* elem_;
+    regex_traits<char>::char_class_type mask_;
+};
+
+const classnames ClassNames[] =
+{
+    {"alnum",  ctype_base::alnum},
+    {"alpha",  ctype_base::alpha},
+    {"blank",  ctype_base::blank},
+    {"cntrl",  ctype_base::cntrl},
+    {"d",      ctype_base::digit},
+    {"digit",  ctype_base::digit},
+    {"graph",  ctype_base::graph},
+    {"lower",  ctype_base::lower},
+    {"print",  ctype_base::print},
+    {"punct",  ctype_base::punct},
+    {"s",      ctype_base::space},
+    {"space",  ctype_base::space},
+    {"upper",  ctype_base::upper},
+    {"w",      regex_traits<char>::__regex_word},
+    {"xdigit", ctype_base::xdigit}
+};
+
+struct use_strcmp
+{
+    bool operator()(const collationnames& x, const char* y)
+        {return strcmp(x.elem_, y) < 0;}
+    bool operator()(const classnames& x, const char* y)
+        {return strcmp(x.elem_, y) < 0;}
+};
+
+}
+
+string
+__get_collation_name(const char* s)
+{
+    const collationnames* i =
+            _VSTD::lower_bound(begin(collatenames), end(collatenames), s, use_strcmp());
+    string r;
+    if (i != end(collatenames) && strcmp(s, i->elem_) == 0)
+        r = char(i->char_);
+    return r;
+}
+
+regex_traits<char>::char_class_type
+__get_classname(const char* s, bool __icase)
+{
+    const classnames* i =
+            _VSTD::lower_bound(begin(ClassNames), end(ClassNames), s, use_strcmp());
+    regex_traits<char>::char_class_type r = 0;
+    if (i != end(ClassNames) && strcmp(s, i->elem_) == 0)
+    {
+        r = i->mask_;
+        if (r == regex_traits<char>::__regex_word)
+            r |= ctype_base::alnum | ctype_base::upper | ctype_base::lower;
+        else if (__icase)
+        {
+            if (r & (ctype_base::lower | ctype_base::upper))
+                r |= ctype_base::alpha;
+        }
+    }
+    return r;
+}
+
+template <>
+void
+__match_any_but_newline<char>::__exec(__state& __s) const
+{
+    if (__s.__current_ != __s.__last_)
+    {
+        switch (*__s.__current_)
+        {
+        case '\r':
+        case '\n':
+            __s.__do_ = __state::__reject;
+            __s.__node_ = nullptr;
+            break;
+        default:
+            __s.__do_ = __state::__accept_and_consume;
+            ++__s.__current_;
+            __s.__node_ = this->first();
+            break;
+        }
+    }
+    else
+    {
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+template <>
+void
+__match_any_but_newline<wchar_t>::__exec(__state& __s) const
+{
+    if (__s.__current_ != __s.__last_)
+    {
+        switch (*__s.__current_)
+        {
+        case '\r':
+        case '\n':
+        case 0x2028:
+        case 0x2029:
+            __s.__do_ = __state::__reject;
+            __s.__node_ = nullptr;
+            break;
+        default:
+            __s.__do_ = __state::__accept_and_consume;
+            ++__s.__current_;
+            __s.__node_ = this->first();
+            break;
+        }
+    }
+    else
+    {
+        __s.__do_ = __state::__reject;
+        __s.__node_ = nullptr;
+    }
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/shared_mutex.cpp b/contrib/libs/cxxsupp/libcxx/src/shared_mutex.cpp
new file mode 100644
index 00000000000..5feef9f4889
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/shared_mutex.cpp
@@ -0,0 +1,118 @@
+//===---------------------- shared_mutex.cpp ------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "__config"
+#ifndef _LIBCPP_HAS_NO_THREADS
+
+#include "shared_mutex"
+#if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
+#pragma comment(lib, "pthread")
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Shared Mutex Base
+__shared_mutex_base::__shared_mutex_base()
+    : __state_(0)
+{
+}
+
+// Exclusive ownership
+
+void
+__shared_mutex_base::lock()
+{
+    unique_lock<mutex> lk(__mut_);
+    while (__state_ & __write_entered_)
+        __gate1_.wait(lk);
+    __state_ |= __write_entered_;
+    while (__state_ & __n_readers_)
+        __gate2_.wait(lk);
+}
+
+bool
+__shared_mutex_base::try_lock()
+{
+    unique_lock<mutex> lk(__mut_);
+    if (__state_ == 0)
+    {
+        __state_ = __write_entered_;
+        return true;
+    }
+    return false;
+}
+
+void
+__shared_mutex_base::unlock()
+{
+    lock_guard<mutex> _(__mut_);
+    __state_ = 0;
+    __gate1_.notify_all();
+}
+
+// Shared ownership
+
+void
+__shared_mutex_base::lock_shared()
+{
+    unique_lock<mutex> lk(__mut_);
+    while ((__state_ & __write_entered_) || (__state_ & __n_readers_) == __n_readers_)
+        __gate1_.wait(lk);
+    unsigned num_readers = (__state_ & __n_readers_) + 1;
+    __state_ &= ~__n_readers_;
+    __state_ |= num_readers;
+}
+
+bool
+__shared_mutex_base::try_lock_shared()
+{
+    unique_lock<mutex> lk(__mut_);
+    unsigned num_readers = __state_ & __n_readers_;
+    if (!(__state_ & __write_entered_) && num_readers != __n_readers_)
+    {
+        ++num_readers;
+        __state_ &= ~__n_readers_;
+        __state_ |= num_readers;
+        return true;
+    }
+    return false;
+}
+
+void
+__shared_mutex_base::unlock_shared()
+{
+    lock_guard<mutex> _(__mut_);
+    unsigned num_readers = (__state_ & __n_readers_) - 1;
+    __state_ &= ~__n_readers_;
+    __state_ |= num_readers;
+    if (__state_ & __write_entered_)
+    {
+        if (num_readers == 0)
+            __gate2_.notify_one();
+    }
+    else
+    {
+        if (num_readers == __n_readers_ - 1)
+            __gate1_.notify_one();
+    }
+}
+
+
+// Shared Timed Mutex
+// These routines are here for ABI stability
+shared_timed_mutex::shared_timed_mutex() : __base() {}
+void shared_timed_mutex::lock()     { return __base.lock(); }
+bool shared_timed_mutex::try_lock() { return __base.try_lock(); }
+void shared_timed_mutex::unlock()   { return __base.unlock(); }
+void shared_timed_mutex::lock_shared() { return __base.lock_shared(); }
+bool shared_timed_mutex::try_lock_shared() { return __base.try_lock_shared(); }
+void shared_timed_mutex::unlock_shared() { return __base.unlock_shared(); }
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !_LIBCPP_HAS_NO_THREADS
diff --git a/contrib/libs/cxxsupp/libcxx/src/stdexcept.cpp b/contrib/libs/cxxsupp/libcxx/src/stdexcept.cpp
new file mode 100644
index 00000000000..f8f335f34ae
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/stdexcept.cpp
@@ -0,0 +1,19 @@
+//===------------------------ stdexcept.cpp -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "stdexcept"
+#include "new"
+#include "string"
+#include "system_error"
+
+
+#ifdef _LIBCPP_ABI_VCRUNTIME
+#include "support/runtime/stdexcept_vcruntime.ipp"
+#else
+#include "support/runtime/stdexcept_default.ipp"
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/src/string.cpp b/contrib/libs/cxxsupp/libcxx/src/string.cpp
new file mode 100644
index 00000000000..c8dae342726
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/string.cpp
@@ -0,0 +1,501 @@
+//===------------------------- string.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "string"
+#include "charconv"
+#include "cstdlib"
+#include "cerrno"
+#include "limits"
+#include "stdexcept"
+#include <stdio.h>
+#include "__debug"
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#   include "cwchar"
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+void __basic_string_common<true>::__throw_length_error() const {
+    _VSTD::__throw_length_error("basic_string");
+}
+
+void __basic_string_common<true>::__throw_out_of_range() const {
+    _VSTD::__throw_out_of_range("basic_string");
+}
+
+#define _LIBCPP_EXTERN_TEMPLATE_DEFINE(...) template __VA_ARGS__;
+#ifdef _LIBCPP_ABI_STRING_OPTIMIZED_EXTERNAL_INSTANTIATION
+    _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE_DEFINE, char)
+#   ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE_DEFINE, wchar_t)
+#   endif
+#else
+    _LIBCPP_STRING_V1_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE_DEFINE, char)
+#   ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+        _LIBCPP_STRING_V1_EXTERN_TEMPLATE_LIST(_LIBCPP_EXTERN_TEMPLATE_DEFINE, wchar_t)
+#   endif
+#endif
+#undef _LIBCPP_EXTERN_TEMPLATE_DEFINE
+
+template string operator+<char, char_traits<char>, allocator<char> >(char const*, string const&);
+
+namespace
+{
+
+template<typename T>
+inline
+void throw_helper( const string& msg )
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw T( msg );
+#else
+    fprintf(stderr, "%s\n", msg.c_str());
+    _VSTD::abort();
+#endif
+}
+
+inline
+void throw_from_string_out_of_range( const string& func )
+{
+    throw_helper<out_of_range>(func + ": out of range");
+}
+
+inline
+void throw_from_string_invalid_arg( const string& func )
+{
+    throw_helper<invalid_argument>(func + ": no conversion");
+}
+
+// as_integer
+
+template<typename V, typename S, typename F>
+inline
+V
+as_integer_helper(const string& func, const S& str, size_t* idx, int base, F f)
+{
+    typename S::value_type* ptr = nullptr;
+    const typename S::value_type* const p = str.c_str();
+    typename remove_reference<decltype(errno)>::type errno_save = errno;
+    errno = 0;
+    V r = f(p, &ptr, base);
+    swap(errno, errno_save);
+    if (errno_save == ERANGE)
+        throw_from_string_out_of_range(func);
+    if (ptr == p)
+        throw_from_string_invalid_arg(func);
+    if (idx)
+        *idx = static_cast<size_t>(ptr - p);
+    return r;
+}
+
+template<typename V, typename S>
+inline
+V
+as_integer(const string& func, const S& s, size_t* idx, int base);
+
+// string
+template<>
+inline
+int
+as_integer(const string& func, const string& s, size_t* idx, int base )
+{
+    // Use long as no Standard string to integer exists.
+    long r = as_integer_helper<long>( func, s, idx, base, strtol );
+    if (r < numeric_limits<int>::min() || numeric_limits<int>::max() < r)
+        throw_from_string_out_of_range(func);
+    return static_cast<int>(r);
+}
+
+template<>
+inline
+long
+as_integer(const string& func, const string& s, size_t* idx, int base )
+{
+    return as_integer_helper<long>( func, s, idx, base, strtol );
+}
+
+template<>
+inline
+unsigned long
+as_integer( const string& func, const string& s, size_t* idx, int base )
+{
+    return as_integer_helper<unsigned long>( func, s, idx, base, strtoul );
+}
+
+template<>
+inline
+long long
+as_integer( const string& func, const string& s, size_t* idx, int base )
+{
+    return as_integer_helper<long long>( func, s, idx, base, strtoll );
+}
+
+template<>
+inline
+unsigned long long
+as_integer( const string& func, const string& s, size_t* idx, int base )
+{
+    return as_integer_helper<unsigned long long>( func, s, idx, base, strtoull );
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+// wstring
+template<>
+inline
+int
+as_integer( const string& func, const wstring& s, size_t* idx, int base )
+{
+    // Use long as no Stantard string to integer exists.
+    long r = as_integer_helper<long>( func, s, idx, base, wcstol );
+    if (r < numeric_limits<int>::min() || numeric_limits<int>::max() < r)
+        throw_from_string_out_of_range(func);
+    return static_cast<int>(r);
+}
+
+template<>
+inline
+long
+as_integer( const string& func, const wstring& s, size_t* idx, int base )
+{
+    return as_integer_helper<long>( func, s, idx, base, wcstol );
+}
+
+template<>
+inline
+unsigned long
+as_integer( const string& func, const wstring& s, size_t* idx, int base )
+{
+    return as_integer_helper<unsigned long>( func, s, idx, base, wcstoul );
+}
+
+template<>
+inline
+long long
+as_integer( const string& func, const wstring& s, size_t* idx, int base )
+{
+    return as_integer_helper<long long>( func, s, idx, base, wcstoll );
+}
+
+template<>
+inline
+unsigned long long
+as_integer( const string& func, const wstring& s, size_t* idx, int base )
+{
+    return as_integer_helper<unsigned long long>( func, s, idx, base, wcstoull );
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+// as_float
+
+template<typename V, typename S, typename F>
+inline
+V
+as_float_helper(const string& func, const S& str, size_t* idx, F f )
+{
+    typename S::value_type* ptr = nullptr;
+    const typename S::value_type* const p = str.c_str();
+    typename remove_reference<decltype(errno)>::type errno_save = errno;
+    errno = 0;
+    V r = f(p, &ptr);
+    swap(errno, errno_save);
+    if (errno_save == ERANGE)
+        throw_from_string_out_of_range(func);
+    if (ptr == p)
+        throw_from_string_invalid_arg(func);
+    if (idx)
+        *idx = static_cast<size_t>(ptr - p);
+    return r;
+}
+
+template<typename V, typename S>
+inline
+V as_float( const string& func, const S& s, size_t* idx = nullptr );
+
+template<>
+inline
+float
+as_float( const string& func, const string& s, size_t* idx )
+{
+    return as_float_helper<float>( func, s, idx, strtof );
+}
+
+template<>
+inline
+double
+as_float(const string& func, const string& s, size_t* idx )
+{
+    return as_float_helper<double>( func, s, idx, strtod );
+}
+
+template<>
+inline
+long double
+as_float( const string& func, const string& s, size_t* idx )
+{
+    return as_float_helper<long double>( func, s, idx, strtold );
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template<>
+inline
+float
+as_float( const string& func, const wstring& s, size_t* idx )
+{
+    return as_float_helper<float>( func, s, idx, wcstof );
+}
+
+template<>
+inline
+double
+as_float( const string& func, const wstring& s, size_t* idx )
+{
+    return as_float_helper<double>( func, s, idx, wcstod );
+}
+
+template<>
+inline
+long double
+as_float( const string& func, const wstring& s, size_t* idx )
+{
+    return as_float_helper<long double>( func, s, idx, wcstold );
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+}  // unnamed namespace
+
+int
+stoi(const string& str, size_t* idx, int base)
+{
+    return as_integer<int>( "stoi", str, idx, base );
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+int
+stoi(const wstring& str, size_t* idx, int base)
+{
+    return as_integer<int>( "stoi", str, idx, base );
+}
+#endif
+
+long
+stol(const string& str, size_t* idx, int base)
+{
+    return as_integer<long>( "stol", str, idx, base );
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+long
+stol(const wstring& str, size_t* idx, int base)
+{
+    return as_integer<long>( "stol", str, idx, base );
+}
+#endif
+
+unsigned long
+stoul(const string& str, size_t* idx, int base)
+{
+    return as_integer<unsigned long>( "stoul", str, idx, base );
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+unsigned long
+stoul(const wstring& str, size_t* idx, int base)
+{
+    return as_integer<unsigned long>( "stoul", str, idx, base );
+}
+#endif
+
+long long
+stoll(const string& str, size_t* idx, int base)
+{
+    return as_integer<long long>( "stoll", str, idx, base );
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+long long
+stoll(const wstring& str, size_t* idx, int base)
+{
+    return as_integer<long long>( "stoll", str, idx, base );
+}
+#endif
+
+unsigned long long
+stoull(const string& str, size_t* idx, int base)
+{
+    return as_integer<unsigned long long>( "stoull", str, idx, base );
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+unsigned long long
+stoull(const wstring& str, size_t* idx, int base)
+{
+    return as_integer<unsigned long long>( "stoull", str, idx, base );
+}
+#endif
+
+float
+stof(const string& str, size_t* idx)
+{
+    return as_float<float>( "stof", str, idx );
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+float
+stof(const wstring& str, size_t* idx)
+{
+    return as_float<float>( "stof", str, idx );
+}
+#endif
+
+double
+stod(const string& str, size_t* idx)
+{
+    return as_float<double>( "stod", str, idx );
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+double
+stod(const wstring& str, size_t* idx)
+{
+    return as_float<double>( "stod", str, idx );
+}
+#endif
+
+long double
+stold(const string& str, size_t* idx)
+{
+    return as_float<long double>( "stold", str, idx );
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+long double
+stold(const wstring& str, size_t* idx)
+{
+    return as_float<long double>( "stold", str, idx );
+}
+#endif
+
+// to_string
+
+namespace
+{
+
+// as_string
+
+template<typename S, typename P, typename V >
+inline
+S
+as_string(P sprintf_like, S s, const typename S::value_type* fmt, V a)
+{
+    typedef typename S::size_type size_type;
+    size_type available = s.size();
+    while (true)
+    {
+        int status = sprintf_like(&s[0], available + 1, fmt, a);
+        if ( status >= 0 )
+        {
+            size_type used = static_cast<size_type>(status);
+            if ( used <= available )
+            {
+                s.resize( used );
+                break;
+            }
+            available = used; // Assume this is advice of how much space we need.
+        }
+        else
+            available = available * 2 + 1;
+        s.resize(available);
+    }
+    return s;
+}
+
+template <class S>
+struct initial_string;
+
+template <>
+struct initial_string<string>
+{
+    string
+    operator()() const
+    {
+        string s;
+        s.resize(s.capacity());
+        return s;
+    }
+};
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <>
+struct initial_string<wstring>
+{
+    wstring
+    operator()() const
+    {
+        wstring s(20, wchar_t());
+        s.resize(s.capacity());
+        return s;
+    }
+};
+
+typedef int (*wide_printf)(wchar_t* __restrict, size_t, const wchar_t*__restrict, ...);
+
+inline
+wide_printf
+get_swprintf()
+{
+#ifndef _LIBCPP_MSVCRT
+    return swprintf;
+#else
+    return static_cast<int (__cdecl*)(wchar_t* __restrict, size_t, const wchar_t*__restrict, ...)>(_snwprintf);
+#endif
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+template <typename S, typename V>
+S i_to_string(V v)
+{
+//  numeric_limits::digits10 returns value less on 1 than desired for unsigned numbers.
+//  For example, for 1-byte unsigned value digits10 is 2 (999 can not be represented),
+//  so we need +1 here.
+    constexpr size_t bufsize = numeric_limits<V>::digits10 + 2;  // +1 for minus, +1 for digits10
+    char buf[bufsize];
+    const auto res = to_chars(buf, buf + bufsize, v);
+    _LIBCPP_ASSERT(res.ec == errc(), "bufsize must be large enough to accomodate the value");
+    return S(buf, res.ptr);
+}
+
+}  // unnamed namespace
+
+string  to_string (int val)                { return i_to_string< string>(val); }
+string  to_string (long val)               { return i_to_string< string>(val); }
+string  to_string (long long val)          { return i_to_string< string>(val); }
+string  to_string (unsigned val)           { return i_to_string< string>(val); }
+string  to_string (unsigned long val)      { return i_to_string< string>(val); }
+string  to_string (unsigned long long val) { return i_to_string< string>(val); }
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+wstring to_wstring(int val)                { return i_to_string<wstring>(val); }
+wstring to_wstring(long val)               { return i_to_string<wstring>(val); }
+wstring to_wstring(long long val)          { return i_to_string<wstring>(val); }
+wstring to_wstring(unsigned val)           { return i_to_string<wstring>(val); }
+wstring to_wstring(unsigned long val)      { return i_to_string<wstring>(val); }
+wstring to_wstring(unsigned long long val) { return i_to_string<wstring>(val); }
+#endif
+
+string  to_string (float val)       { return as_string(snprintf,       initial_string< string>()(),   "%f", val); }
+string  to_string (double val)      { return as_string(snprintf,       initial_string< string>()(),   "%f", val); }
+string  to_string (long double val) { return as_string(snprintf,       initial_string< string>()(),  "%Lf", val); }
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+wstring to_wstring(float val)       { return as_string(get_swprintf(), initial_string<wstring>()(),  L"%f", val); }
+wstring to_wstring(double val)      { return as_string(get_swprintf(), initial_string<wstring>()(),  L"%f", val); }
+wstring to_wstring(long double val) { return as_string(get_swprintf(), initial_string<wstring>()(), L"%Lf", val); }
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/strstream.cpp b/contrib/libs/cxxsupp/libcxx/src/strstream.cpp
new file mode 100644
index 00000000000..ae66806833a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/strstream.cpp
@@ -0,0 +1,335 @@
+//===------------------------ strstream.cpp -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "strstream"
+#include "algorithm"
+#include "climits"
+#include "cstring"
+#include "cstdlib"
+#include "__debug"
+#include "__undef_macros"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+strstreambuf::strstreambuf(streamsize __alsize)
+    : __strmode_(__dynamic),
+      __alsize_(__alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+}
+
+strstreambuf::strstreambuf(void* (*__palloc)(size_t), void (*__pfree)(void*))
+    : __strmode_(__dynamic),
+      __alsize_(__default_alsize),
+      __palloc_(__palloc),
+      __pfree_(__pfree)
+{
+}
+
+void
+strstreambuf::__init(char* __gnext, streamsize __n, char* __pbeg)
+{
+    if (__n == 0)
+        __n = static_cast<streamsize>(strlen(__gnext));
+    else if (__n < 0)
+        __n = INT_MAX;
+    if (__pbeg == nullptr)
+        setg(__gnext, __gnext, __gnext + __n);
+    else
+    {
+        setg(__gnext, __gnext, __pbeg);
+        setp(__pbeg, __pbeg + __n);
+    }
+}
+
+strstreambuf::strstreambuf(char* __gnext, streamsize __n, char* __pbeg)
+    : __strmode_(),
+      __alsize_(__default_alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+    __init(__gnext, __n, __pbeg);
+}
+
+strstreambuf::strstreambuf(const char* __gnext, streamsize __n)
+    : __strmode_(__constant),
+      __alsize_(__default_alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+    __init(const_cast<char *>(__gnext), __n, nullptr);
+}
+
+strstreambuf::strstreambuf(signed char* __gnext, streamsize __n, signed char* __pbeg)
+    : __strmode_(),
+      __alsize_(__default_alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+    __init(const_cast<char *>(reinterpret_cast<const char*>(__gnext)), __n, reinterpret_cast<char*>(__pbeg));
+}
+
+strstreambuf::strstreambuf(const signed char* __gnext, streamsize __n)
+    : __strmode_(__constant),
+      __alsize_(__default_alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+    __init(const_cast<char *>(reinterpret_cast<const char*>(__gnext)), __n, nullptr);
+}
+
+strstreambuf::strstreambuf(unsigned char* __gnext, streamsize __n, unsigned char* __pbeg)
+    : __strmode_(),
+      __alsize_(__default_alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+    __init(const_cast<char *>(reinterpret_cast<const char*>(__gnext)), __n, reinterpret_cast<char*>(__pbeg));
+}
+
+strstreambuf::strstreambuf(const unsigned char* __gnext, streamsize __n)
+    : __strmode_(__constant),
+      __alsize_(__default_alsize),
+      __palloc_(nullptr),
+      __pfree_(nullptr)
+{
+    __init(const_cast<char *>(reinterpret_cast<const char*>(__gnext)), __n, nullptr);
+}
+
+strstreambuf::~strstreambuf()
+{
+    if (eback() && (__strmode_ & __allocated) != 0 && (__strmode_ & __frozen) == 0)
+    {
+        if (__pfree_)
+            __pfree_(eback());
+        else
+            delete [] eback();
+    }
+}
+
+void
+strstreambuf::swap(strstreambuf& __rhs)
+{
+    streambuf::swap(__rhs);
+    _VSTD::swap(__strmode_, __rhs.__strmode_);
+    _VSTD::swap(__alsize_, __rhs.__alsize_);
+    _VSTD::swap(__palloc_, __rhs.__palloc_);
+    _VSTD::swap(__pfree_, __rhs.__pfree_);
+}
+
+void
+strstreambuf::freeze(bool __freezefl)
+{
+    if (__strmode_ & __dynamic)
+    {
+        if (__freezefl)
+            __strmode_ |= __frozen;
+        else
+            __strmode_ &= ~__frozen;
+    }
+}
+
+char*
+strstreambuf::str()
+{
+    if (__strmode_ & __dynamic)
+        __strmode_ |= __frozen;
+    return eback();
+}
+
+int
+strstreambuf::pcount() const
+{
+    return static_cast<int>(pptr() - pbase());
+}
+
+strstreambuf::int_type
+strstreambuf::overflow(int_type __c)
+{
+    if (__c == EOF)
+        return int_type(0);
+    if (pptr() == epptr())
+    {
+        if ((__strmode_ & __dynamic) == 0 || (__strmode_ & __frozen) != 0)
+            return int_type(EOF);
+        size_t old_size = static_cast<size_t> ((epptr() ? epptr() : egptr()) - eback());
+        size_t new_size = max<size_t>(static_cast<size_t>(__alsize_), 2*old_size);
+        if (new_size == 0)
+            new_size = __default_alsize;
+        char* buf = nullptr;
+        if (__palloc_)
+            buf = static_cast<char*>(__palloc_(new_size));
+        else
+            buf = new char[new_size];
+        if (buf == nullptr)
+            return int_type(EOF);
+        if (old_size != 0) {
+            _LIBCPP_ASSERT(eback(), "overflow copying from NULL");
+            memcpy(buf, eback(), static_cast<size_t>(old_size));
+        }
+        ptrdiff_t ninp = gptr()  - eback();
+        ptrdiff_t einp = egptr() - eback();
+        ptrdiff_t nout = pptr()  - pbase();
+        if (__strmode_ & __allocated)
+        {
+            if (__pfree_)
+                __pfree_(eback());
+            else
+                delete [] eback();
+        }
+        setg(buf, buf + ninp, buf + einp);
+        setp(buf + einp, buf + new_size);
+        __pbump(nout);
+        __strmode_ |= __allocated;
+    }
+    *pptr() = static_cast<char>(__c);
+    pbump(1);
+    return int_type(static_cast<unsigned char>(__c));
+}
+
+strstreambuf::int_type
+strstreambuf::pbackfail(int_type __c)
+{
+    if (eback() == gptr())
+        return EOF;
+    if (__c == EOF)
+    {
+        gbump(-1);
+        return int_type(0);
+    }
+    if (__strmode_ & __constant)
+    {
+        if (gptr()[-1] == static_cast<char>(__c))
+        {
+            gbump(-1);
+            return __c;
+        }
+        return EOF;
+    }
+    gbump(-1);
+    *gptr() = static_cast<char>(__c);
+    return __c;
+}
+
+strstreambuf::int_type
+strstreambuf::underflow()
+{
+    if (gptr() == egptr())
+    {
+        if (egptr() >= pptr())
+            return EOF;
+        setg(eback(), gptr(), pptr());
+    }
+    return int_type(static_cast<unsigned char>(*gptr()));
+}
+
+strstreambuf::pos_type
+strstreambuf::seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __which)
+{
+    off_type __p(-1);
+    bool pos_in = (__which & ios::in) != 0;
+    bool pos_out = (__which & ios::out) != 0;
+    bool legal = false;
+    switch (__way)
+    {
+    case ios::beg:
+    case ios::end:
+        if (pos_in || pos_out)
+            legal = true;
+        break;
+    case ios::cur:
+        if (pos_in != pos_out)
+            legal = true;
+        break;
+    }
+    if (pos_in && gptr() == nullptr)
+        legal = false;
+    if (pos_out && pptr() == nullptr)
+        legal = false;
+    if (legal)
+    {
+        off_type newoff;
+        char* seekhigh = epptr() ? epptr() : egptr();
+        switch (__way)
+        {
+        case ios::beg:
+            newoff = 0;
+            break;
+        case ios::cur:
+            newoff = (pos_in ? gptr() : pptr()) - eback();
+            break;
+        case ios::end:
+            newoff = seekhigh - eback();
+            break;
+        default:
+            _LIBCPP_UNREACHABLE();
+        }
+        newoff += __off;
+        if (0 <= newoff && newoff <= seekhigh - eback())
+        {
+            char* newpos = eback() + newoff;
+            if (pos_in)
+                setg(eback(), newpos, _VSTD::max(newpos, egptr()));
+            if (pos_out)
+            {
+                // min(pbase, newpos), newpos, epptr()
+                __off = epptr() - newpos;
+                setp(min(pbase(), newpos), epptr());
+                __pbump((epptr() - pbase()) - __off);
+            }
+            __p = newoff;
+        }
+    }
+    return pos_type(__p);
+}
+
+strstreambuf::pos_type
+strstreambuf::seekpos(pos_type __sp, ios_base::openmode __which)
+{
+    off_type __p(-1);
+    bool pos_in = (__which & ios::in) != 0;
+    bool pos_out = (__which & ios::out) != 0;
+    if (pos_in || pos_out)
+    {
+        if (!((pos_in && gptr() == nullptr) || (pos_out && pptr() == nullptr)))
+        {
+            off_type newoff = __sp;
+            char* seekhigh = epptr() ? epptr() : egptr();
+            if (0 <= newoff && newoff <= seekhigh - eback())
+            {
+                char* newpos = eback() + newoff;
+                if (pos_in)
+                    setg(eback(), newpos, _VSTD::max(newpos, egptr()));
+                if (pos_out)
+                {
+                    // min(pbase, newpos), newpos, epptr()
+                    off_type temp = epptr() - newpos;
+                    setp(min(pbase(), newpos), epptr());
+                    __pbump((epptr() - pbase()) - temp);
+                }
+                __p = newoff;
+            }
+        }
+    }
+    return pos_type(__p);
+}
+
+istrstream::~istrstream()
+{
+}
+
+ostrstream::~ostrstream()
+{
+}
+
+strstream::~strstream()
+{
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/ibm/mbsnrtowcs.cpp b/contrib/libs/cxxsupp/libcxx/src/support/ibm/mbsnrtowcs.cpp
new file mode 100644
index 00000000000..125bdbea1c5
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/ibm/mbsnrtowcs.cpp
@@ -0,0 +1,95 @@
+//===----------------------- mbsnrtowcs.cpp -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <cstddef> // size_t
+#include <cwchar>  // mbstate_t
+#include <limits.h> // MB_LEN_MAX
+#include <string.h> // wmemcpy
+
+// Returns the number of wide characters found in the multi byte sequence `src`
+// (of `src_size_bytes`), that fit in the buffer `dst` (of `max_dest_chars`
+// elements size). The count returned excludes the null terminator.
+// When `dst` is NULL, no characters are copied to `dst`.
+// Returns (size_t) -1 when an invalid sequence is encountered.
+// Leaves *`src` pointing to the next character to convert or NULL
+// if a null character was converted from *`src`.
+_LIBCPP_FUNC_VIS
+size_t mbsnrtowcs(wchar_t *__restrict dst, const char **__restrict src,
+                   size_t src_size_bytes, size_t max_dest_chars,
+                   mbstate_t *__restrict ps) {
+  const size_t terminated_sequence = static_cast<size_t>(0);
+  const size_t invalid_sequence = static_cast<size_t>(-1);
+  const size_t incomplete_sequence = static_cast<size_t>(-2);
+
+  size_t source_converted;
+  size_t dest_converted;
+  size_t result = 0;
+
+  // If `dst` is null then `max_dest_chars` should be ignored according to the
+  // standard. Setting `max_dest_chars` to a large value has this effect.
+  if (dst == nullptr)
+    max_dest_chars = static_cast<size_t>(-1);
+
+  for (dest_converted = source_converted = 0;
+       source_converted < src_size_bytes && (!dst || dest_converted < max_dest_chars);
+       ++dest_converted, source_converted += result) {
+    // Converts one multi byte character.
+    // If result (char_size) is greater than 0, it's the size in bytes of that character.
+    // If result (char_size) is zero, it indicates that the null character has been found.
+    // Otherwise, it's an error and errno may be set.
+    size_t source_remaining = src_size_bytes - source_converted;
+    size_t dest_remaining = max_dest_chars - dest_converted;
+
+    if (dst == nullptr) {
+      result = mbrtowc(NULL, *src + source_converted, source_remaining, ps);
+    } else if (dest_remaining >= source_remaining) {
+      // dst has enough space to translate in-place.
+      result = mbrtowc(dst + dest_converted, *src + source_converted, source_remaining, ps);
+    } else {
+      /*
+      * dst may not have enough space, so use a temporary buffer.
+      *
+      * We need to save a copy of the conversion state
+      * here so we can restore it if the multibyte
+      * character is too long for the buffer.
+      */
+      wchar_t buff[MB_LEN_MAX];
+      mbstate_t mbstate_tmp;
+
+      if (ps != nullptr)
+        mbstate_tmp = *ps;
+      result = mbrtowc(buff, *src + source_converted, source_remaining, ps);
+
+      if (result > dest_remaining) {
+        // Multi-byte sequence for character won't fit.
+        if (ps != nullptr)
+          *ps = mbstate_tmp;
+        break;
+      } else {
+        // The buffer was used, so we need copy the translation to dst.
+        wmemcpy(dst, buff, result);
+      }
+    }
+
+    // Don't do anything to change errno from here on.
+    if (result == invalid_sequence || result == terminated_sequence || result == incomplete_sequence) {
+      break;
+    }
+  }
+
+  if (dst) {
+    if (result == terminated_sequence)
+      *src = NULL;
+    else
+      *src += source_converted;
+  }
+  if (result == invalid_sequence)
+    return invalid_sequence;
+
+  return dest_converted;
+}
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/ibm/wcsnrtombs.cpp b/contrib/libs/cxxsupp/libcxx/src/support/ibm/wcsnrtombs.cpp
new file mode 100644
index 00000000000..01c6241dc54
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/ibm/wcsnrtombs.cpp
@@ -0,0 +1,93 @@
+//===----------------------- wcsnrtombs.cpp -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <cwchar>  // mbstate_t
+#include <limits.h> // MB_LEN_MAX
+#include <stdlib.h> // MB_CUR_MAX, size_t
+#include <string.h> // memcpy
+
+// Converts `max_source_chars` from the wide character buffer pointer to by *`src`,
+// into the multi byte character sequence buffer stored at `dst`, which must be
+// `dst_size_bytes` bytes in size. Returns the number of bytes in the sequence
+// converted from *src, excluding the null terminator.
+// Returns (size_t) -1 if an error occurs and sets errno.
+// If `dst` is NULL, `dst_size_bytes` is ignored and no bytes are copied to `dst`.
+_LIBCPP_FUNC_VIS
+size_t wcsnrtombs(char *__restrict dst, const wchar_t **__restrict src,
+                   size_t max_source_chars, size_t dst_size_bytes,
+                   mbstate_t *__restrict ps) {
+
+  const size_t invalid_wchar = static_cast<size_t>(-1);
+
+  size_t source_converted;
+  size_t dest_converted;
+  size_t result = 0;
+
+  // If `dst` is null then `dst_size_bytes` should be ignored according to the
+  // standard. Setting dst_size_bytes to a large value has this effect.
+  if (dst == nullptr)
+    dst_size_bytes = static_cast<size_t>(-1);
+
+  for (dest_converted = source_converted = 0;
+       source_converted < max_source_chars && (!dst || dest_converted < dst_size_bytes);
+       ++source_converted, dest_converted += result) {
+    wchar_t c = (*src)[source_converted];
+    size_t dest_remaining = dst_size_bytes - dest_converted;
+
+    if (dst == nullptr) {
+      result = wcrtomb(NULL, c, ps);
+    } else if (dest_remaining >= static_cast<size_t>(MB_CUR_MAX)) {
+      // dst has enough space to translate in-place.
+      result = wcrtomb(dst + dest_converted, c, ps);
+    } else {
+      /*
+      * dst may not have enough space, so use a temporary buffer.
+      *
+      * We need to save a copy of the conversion state
+      * here so we can restore it if the multibyte
+      * character is too long for the buffer.
+      */
+      char buff[MB_LEN_MAX];
+      mbstate_t mbstate_tmp;
+
+      if (ps != nullptr)
+        mbstate_tmp = *ps;
+      result = wcrtomb(buff, c, ps);
+
+      if (result > dest_remaining) {
+        // Multi-byte sequence for character won't fit.
+        if (ps != nullptr)
+          *ps = mbstate_tmp;
+        if (result != invalid_wchar)
+          break;
+      } else {
+        // The buffer was used, so we need copy the translation to dst.
+        memcpy(dst, buff, result);
+      }
+    }
+
+    // result (char_size) contains the size of the multi-byte-sequence converted.
+    // Otherwise, result (char_size) is (size_t) -1 and wcrtomb() sets the errno.
+    if (result == invalid_wchar) {
+      if (dst)
+        *src = *src + source_converted;
+      return invalid_wchar;
+    }
+
+    if (c == L'\0') {
+      if (dst)
+        *src = NULL;
+      return dest_converted;
+    }
+  }
+
+  if (dst)
+    *src = *src + source_converted;
+
+  return dest_converted;
+}
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/ibm/xlocale_zos.cpp b/contrib/libs/cxxsupp/libcxx/src/support/ibm/xlocale_zos.cpp
new file mode 100644
index 00000000000..90c1ba95a31
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/ibm/xlocale_zos.cpp
@@ -0,0 +1,137 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <__support/ibm/xlocale.h>
+#include <sstream>
+#include <vector>
+
+#ifdef __cplusplus
+extern "C" {
+#endif // __cplusplus
+
+locale_t newlocale(int category_mask, const char* locale, locale_t base) {
+  // Maintain current locale name(s) to restore later.
+  std::string current_loc_name(setlocale(LC_ALL, 0));
+
+  // Check for errors.
+  if (category_mask == LC_ALL_MASK && setlocale(LC_ALL, locale) == NULL) {
+    errno = EINVAL;
+    return (locale_t)0;
+  } else {
+    for (int _Cat = 0; _Cat <= _LC_MAX; ++_Cat) {
+      if ((_CATMASK(_Cat) & category_mask) != 0 && setlocale(_Cat, locale) == NULL) {
+        setlocale(LC_ALL, current_loc_name.c_str());
+        errno = EINVAL;
+        return (locale_t)0;
+      }
+    }
+  }
+
+  // Create new locale.
+  locale_t newloc = new locale_struct();
+
+  if (base) {
+    if (category_mask != LC_ALL_MASK) {
+      // Copy base when it will not be overwritten.
+      memcpy(newloc, base, sizeof (locale_struct));
+      newloc->category_mask = category_mask | base->category_mask;
+    }
+    delete base;
+  } else {
+    newloc->category_mask = category_mask;
+  }
+
+  if (category_mask & LC_COLLATE_MASK)
+    newloc->lc_collate = locale;
+  if (category_mask & LC_CTYPE_MASK)
+    newloc->lc_ctype = locale;
+  if (category_mask & LC_MONETARY_MASK)
+    newloc->lc_monetary = locale;
+  if (category_mask & LC_NUMERIC_MASK)
+    newloc->lc_numeric = locale;
+  if (category_mask & LC_TIME_MASK)
+    newloc->lc_time = locale;
+  if (category_mask & LC_MESSAGES_MASK)
+    newloc->lc_messages = locale;
+
+  // Restore current locale.
+  setlocale(LC_ALL, current_loc_name.c_str());
+  return (locale_t)newloc;
+}
+
+void freelocale(locale_t locobj) {
+  delete locobj;
+}
+
+locale_t uselocale(locale_t newloc) {
+  // Maintain current locale name(s).
+  std::string current_loc_name(setlocale(LC_ALL, 0));
+
+  if (newloc) {
+    // Set locales and check for errors.
+    bool is_error =
+      (newloc->category_mask & LC_COLLATE_MASK &&
+        setlocale(LC_COLLATE, newloc->lc_collate.c_str()) == NULL) ||
+      (newloc->category_mask & LC_CTYPE_MASK &&
+        setlocale(LC_CTYPE, newloc->lc_ctype.c_str()) == NULL) ||
+      (newloc->category_mask & LC_MONETARY_MASK &&
+        setlocale(LC_MONETARY, newloc->lc_monetary.c_str()) == NULL) ||
+      (newloc->category_mask & LC_NUMERIC_MASK &&
+        setlocale(LC_NUMERIC, newloc->lc_numeric.c_str()) == NULL) ||
+      (newloc->category_mask & LC_TIME_MASK &&
+        setlocale(LC_TIME, newloc->lc_time.c_str()) == NULL) ||
+      (newloc->category_mask & LC_MESSAGES_MASK &&
+        setlocale(LC_MESSAGES, newloc->lc_messages.c_str()) == NULL);
+
+    if (is_error) {
+      setlocale(LC_ALL, current_loc_name.c_str());
+      errno = EINVAL;
+      return (locale_t)0;
+    }
+  }
+
+  // Construct and return previous locale.
+  locale_t previous_loc = new locale_struct();
+
+  // current_loc_name might be a comma-separated locale name list.
+  if (current_loc_name.find(',') != std::string::npos) {
+    // Tokenize locale name list.
+    const char delimiter = ',';
+    std::vector<std::string> tokenized;
+    std::stringstream ss(current_loc_name);
+    std::string s;
+
+    while (std::getline(ss, s, delimiter)) {
+        tokenized.push_back(s);
+    }
+
+    _LIBCPP_ASSERT(tokenized.size() >= _NCAT, "locale-name list is too short");
+
+    previous_loc->lc_collate = tokenized[LC_COLLATE];
+    previous_loc->lc_ctype = tokenized[LC_CTYPE];
+    previous_loc->lc_monetary = tokenized[LC_MONETARY];
+    previous_loc->lc_numeric = tokenized[LC_NUMERIC];
+    previous_loc->lc_time = tokenized[LC_TIME];
+    // Skip LC_TOD.
+    previous_loc->lc_messages = tokenized[LC_MESSAGES];
+  } else {
+    previous_loc->lc_collate = current_loc_name;
+    previous_loc->lc_ctype = current_loc_name;
+    previous_loc->lc_monetary = current_loc_name;
+    previous_loc->lc_numeric = current_loc_name;
+    previous_loc->lc_time = current_loc_name;
+    previous_loc->lc_messages = current_loc_name;
+  }
+
+  previous_loc->category_mask = LC_ALL_MASK;
+  return previous_loc;
+}
+
+#ifdef __cplusplus
+}
+#endif // __cplusplus
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_fallback.ipp b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_fallback.ipp
new file mode 100644
index 00000000000..6ebaeee2a51
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_fallback.ipp
@@ -0,0 +1,161 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <cstdio>
+#include "../../include/atomic_support.h"
+
+namespace std {
+
+_LIBCPP_SAFE_STATIC static std::terminate_handler  __terminate_handler;
+_LIBCPP_SAFE_STATIC static std::unexpected_handler __unexpected_handler;
+
+
+// libcxxrt provides implementations of these functions itself.
+unexpected_handler
+set_unexpected(unexpected_handler func) noexcept
+{
+  return __libcpp_atomic_exchange(&__unexpected_handler, func);
+}
+
+unexpected_handler
+get_unexpected() noexcept
+{
+  return __libcpp_atomic_load(&__unexpected_handler);
+
+}
+
+_LIBCPP_NORETURN
+void unexpected()
+{
+    (*get_unexpected())();
+    // unexpected handler should not return
+    terminate();
+}
+
+terminate_handler
+set_terminate(terminate_handler func) noexcept
+{
+  return __libcpp_atomic_exchange(&__terminate_handler, func);
+}
+
+terminate_handler
+get_terminate() noexcept
+{
+  return __libcpp_atomic_load(&__terminate_handler);
+}
+
+_LIBCPP_NORETURN
+void
+terminate() noexcept
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        (*get_terminate())();
+        // handler should not return
+        fprintf(stderr, "terminate_handler unexpectedly returned\n");
+        ::abort();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        // handler should not throw exception
+        fprintf(stderr, "terminate_handler unexpectedly threw an exception\n");
+        ::abort();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+bool uncaught_exception() noexcept { return uncaught_exceptions() > 0; }
+
+int uncaught_exceptions() noexcept
+{
+#warning uncaught_exception not yet implemented
+  fprintf(stderr, "uncaught_exceptions not yet implemented\n");
+  ::abort();
+}
+
+
+exception::~exception() noexcept
+{
+}
+
+const char* exception::what() const noexcept
+{
+  return "std::exception";
+}
+
+bad_exception::~bad_exception() noexcept
+{
+}
+
+const char* bad_exception::what() const noexcept
+{
+  return "std::bad_exception";
+}
+
+
+bad_alloc::bad_alloc() noexcept
+{
+}
+
+bad_alloc::~bad_alloc() noexcept
+{
+}
+
+const char*
+bad_alloc::what() const noexcept
+{
+    return "std::bad_alloc";
+}
+
+bad_array_new_length::bad_array_new_length() noexcept
+{
+}
+
+bad_array_new_length::~bad_array_new_length() noexcept
+{
+}
+
+const char*
+bad_array_new_length::what() const noexcept
+{
+    return "bad_array_new_length";
+}
+
+bad_cast::bad_cast() noexcept
+{
+}
+
+bad_typeid::bad_typeid() noexcept
+{
+}
+
+bad_cast::~bad_cast() noexcept
+{
+}
+
+const char*
+bad_cast::what() const noexcept
+{
+  return "std::bad_cast";
+}
+
+bad_typeid::~bad_typeid() noexcept
+{
+}
+
+const char*
+bad_typeid::what() const noexcept
+{
+  return "std::bad_typeid";
+}
+
+} // namespace std
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_glibcxx.ipp b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_glibcxx.ipp
new file mode 100644
index 00000000000..e478ccbb6e3
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_glibcxx.ipp
@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __GLIBCXX__
+#error header can only be used when targeting libstdc++ or libsupc++
+#endif
+
+namespace std {
+
+bad_alloc::bad_alloc() noexcept
+{
+}
+
+bad_array_new_length::bad_array_new_length() noexcept
+{
+}
+
+bad_cast::bad_cast() noexcept
+{
+}
+
+bad_typeid::bad_typeid() noexcept
+{
+}
+
+} // namespace std
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_libcxxabi.ipp b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_libcxxabi.ipp
new file mode 100644
index 00000000000..ee15e437e60
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_libcxxabi.ipp
@@ -0,0 +1,27 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPPABI_VERSION
+#error this header can only be used with libc++abi
+#endif
+
+namespace std {
+
+bool uncaught_exception() noexcept { return uncaught_exceptions() > 0; }
+
+int uncaught_exceptions() noexcept
+{
+# if _LIBCPPABI_VERSION > 1001
+    return __cxa_uncaught_exceptions();
+# else
+    return __cxa_uncaught_exception() ? 1 : 0;
+# endif
+}
+
+} // namespace std
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_libcxxrt.ipp b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_libcxxrt.ipp
new file mode 100644
index 00000000000..4e428d216cf
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_libcxxrt.ipp
@@ -0,0 +1,25 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LIBCXX_BUILDING_LIBCXXRT
+#error this header may only be used when targeting libcxxrt
+#endif
+
+namespace std {
+
+bad_exception::~bad_exception() noexcept
+{
+}
+
+const char* bad_exception::what() const noexcept
+{
+  return "std::bad_exception";
+}
+
+} // namespace std
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_msvc.ipp b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_msvc.ipp
new file mode 100644
index 00000000000..4eb1803f0b6
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_msvc.ipp
@@ -0,0 +1,173 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_ABI_MICROSOFT
+#error this header can only be used when targeting the MSVC ABI
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <__config>
+
+#ifdef _LIBCPP_COMPILER_MSVC
+// We don't want to depend on MSVC headers but
+// we have conflicting definitions otherwise due to
+// some other dependency on eh.h.
+#include _LIBCPP_MSVC_INCLUDE(eh.h)
+
+#else
+extern "C" {
+typedef void (__cdecl* terminate_handler)();
+_LIBCPP_CRT_FUNC terminate_handler __cdecl set_terminate(
+    terminate_handler _NewTerminateHandler) throw();
+_LIBCPP_CRT_FUNC terminate_handler __cdecl _get_terminate();
+
+typedef void (__cdecl* unexpected_handler)();
+unexpected_handler __cdecl set_unexpected(
+    unexpected_handler _NewUnexpectedHandler) throw();
+unexpected_handler __cdecl _get_unexpected();
+
+int __cdecl __uncaught_exceptions();
+}
+#endif
+
+namespace std {
+
+unexpected_handler
+set_unexpected(unexpected_handler func) noexcept {
+  return ::set_unexpected(func);
+}
+
+unexpected_handler get_unexpected() noexcept {
+  return ::_get_unexpected();
+}
+
+_LIBCPP_NORETURN
+void unexpected() {
+    (*get_unexpected())();
+    // unexpected handler should not return
+    terminate();
+}
+
+terminate_handler set_terminate(terminate_handler func) noexcept {
+  return ::set_terminate(func);
+}
+
+terminate_handler get_terminate() noexcept {
+  return ::_get_terminate();
+}
+
+_LIBCPP_NORETURN
+void terminate() noexcept
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    try
+    {
+#endif // _LIBCPP_NO_EXCEPTIONS
+        (*get_terminate())();
+        // handler should not return
+        fprintf(stderr, "terminate_handler unexpectedly returned\n");
+        ::abort();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    }
+    catch (...)
+    {
+        // handler should not throw exception
+        fprintf(stderr, "terminate_handler unexpectedly threw an exception\n");
+        ::abort();
+    }
+#endif // _LIBCPP_NO_EXCEPTIONS
+}
+
+bool uncaught_exception() noexcept { return uncaught_exceptions() > 0; }
+
+int uncaught_exceptions() noexcept {
+    return __uncaught_exceptions();
+}
+
+#if !defined(_LIBCPP_ABI_VCRUNTIME)
+bad_cast::bad_cast() noexcept
+{
+}
+
+bad_cast::~bad_cast() noexcept
+{
+}
+
+const char *
+bad_cast::what() const noexcept
+{
+  return "std::bad_cast";
+}
+
+bad_typeid::bad_typeid() noexcept
+{
+}
+
+bad_typeid::~bad_typeid() noexcept
+{
+}
+
+const char *
+bad_typeid::what() const noexcept
+{
+  return "std::bad_typeid";
+}
+
+exception::~exception() noexcept
+{
+}
+
+const char* exception::what() const noexcept
+{
+  return "std::exception";
+}
+
+
+bad_exception::~bad_exception() noexcept
+{
+}
+
+const char* bad_exception::what() const noexcept
+{
+  return "std::bad_exception";
+}
+
+
+bad_alloc::bad_alloc() noexcept
+{
+}
+
+bad_alloc::~bad_alloc() noexcept
+{
+}
+
+const char*
+bad_alloc::what() const noexcept
+{
+    return "std::bad_alloc";
+}
+
+bad_array_new_length::bad_array_new_length() noexcept
+{
+}
+
+bad_array_new_length::~bad_array_new_length() noexcept
+{
+}
+
+const char*
+bad_array_new_length::what() const noexcept
+{
+    return "bad_array_new_length";
+}
+#endif // !_LIBCPP_ABI_VCRUNTIME
+
+} // namespace std
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_pointer_cxxabi.ipp b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_pointer_cxxabi.ipp
new file mode 100644
index 00000000000..33aa94502b7
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_pointer_cxxabi.ipp
@@ -0,0 +1,73 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef HAVE_DEPENDENT_EH_ABI
+#error this header may only be used with libc++abi or libcxxrt
+#endif
+
+namespace std {
+
+exception_ptr::~exception_ptr() noexcept {
+  __cxa_decrement_exception_refcount(__ptr_);
+}
+
+exception_ptr::exception_ptr(const exception_ptr& other) noexcept
+    : __ptr_(other.__ptr_)
+{
+    __cxa_increment_exception_refcount(__ptr_);
+}
+
+exception_ptr& exception_ptr::operator=(const exception_ptr& other) noexcept
+{
+    if (__ptr_ != other.__ptr_)
+    {
+        __cxa_increment_exception_refcount(other.__ptr_);
+        __cxa_decrement_exception_refcount(__ptr_);
+        __ptr_ = other.__ptr_;
+    }
+    return *this;
+}
+
+nested_exception::nested_exception() noexcept
+    : __ptr_(current_exception())
+{
+}
+
+nested_exception::~nested_exception() noexcept
+{
+}
+
+_LIBCPP_NORETURN
+void
+nested_exception::rethrow_nested() const
+{
+    if (__ptr_ == nullptr)
+        terminate();
+    rethrow_exception(__ptr_);
+}
+
+exception_ptr current_exception() noexcept
+{
+    // be nicer if there was a constructor that took a ptr, then
+    // this whole function would be just:
+    //    return exception_ptr(__cxa_current_primary_exception());
+    exception_ptr ptr;
+    ptr.__ptr_ = __cxa_current_primary_exception();
+    return ptr;
+}
+
+_LIBCPP_NORETURN
+void rethrow_exception(exception_ptr p)
+{
+    __cxa_rethrow_primary_exception(p.__ptr_);
+    // if p.__ptr_ is NULL, above returns so we terminate
+    terminate();
+}
+
+} // namespace std
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_pointer_glibcxx.ipp b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_pointer_glibcxx.ipp
new file mode 100644
index 00000000000..983a08808dc
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_pointer_glibcxx.ipp
@@ -0,0 +1,77 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// libsupc++ does not implement the dependent EH ABI and the functionality
+// it uses to implement std::exception_ptr (which it declares as an alias of
+// std::__exception_ptr::exception_ptr) is not directly exported to clients. So
+// we have little choice but to hijack std::__exception_ptr::exception_ptr's
+// (which fortunately has the same layout as our std::exception_ptr) copy
+// constructor, assignment operator and destructor (which are part of its
+// stable ABI), and its rethrow_exception(std::__exception_ptr::exception_ptr)
+// function.
+
+namespace std {
+
+namespace __exception_ptr
+{
+
+struct exception_ptr
+{
+    void* __ptr_;
+
+    exception_ptr(const exception_ptr&) noexcept;
+    exception_ptr& operator=(const exception_ptr&) noexcept;
+    ~exception_ptr() noexcept;
+};
+
+}
+
+_LIBCPP_NORETURN void rethrow_exception(__exception_ptr::exception_ptr);
+
+exception_ptr::~exception_ptr() noexcept
+{
+    reinterpret_cast<__exception_ptr::exception_ptr*>(this)->~exception_ptr();
+}
+
+exception_ptr::exception_ptr(const exception_ptr& other) noexcept
+    : __ptr_(other.__ptr_)
+{
+    new (reinterpret_cast<void*>(this)) __exception_ptr::exception_ptr(
+        reinterpret_cast<const __exception_ptr::exception_ptr&>(other));
+}
+
+exception_ptr& exception_ptr::operator=(const exception_ptr& other) noexcept
+{
+    *reinterpret_cast<__exception_ptr::exception_ptr*>(this) =
+        reinterpret_cast<const __exception_ptr::exception_ptr&>(other);
+    return *this;
+}
+
+nested_exception::nested_exception() noexcept
+    : __ptr_(current_exception())
+{
+}
+
+
+_LIBCPP_NORETURN
+void
+nested_exception::rethrow_nested() const
+{
+    if (__ptr_ == nullptr)
+        terminate();
+    rethrow_exception(__ptr_);
+}
+
+_LIBCPP_NORETURN
+void rethrow_exception(exception_ptr p)
+{
+    rethrow_exception(reinterpret_cast<__exception_ptr::exception_ptr&>(p));
+}
+
+} // namespace std
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_pointer_msvc.ipp b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_pointer_msvc.ipp
new file mode 100644
index 00000000000..300acbf759c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_pointer_msvc.ipp
@@ -0,0 +1,258 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <atomic>
+#include <cstdint>
+#include <cstring>
+#include <malloc.h>
+#include <windows.h> // For RtlPcToFileHeader function
+
+struct EHCatchableType {
+  uint32_t properties;
+  int32_t type_info;
+  uint32_t non_virtual_adjustment;
+  uint32_t offset_to_virtual_base_ptr;
+  uint32_t virtual_base_table_index;
+  uint32_t size;
+  int32_t copy_function;
+};
+
+struct EHCatchableTypeArray {
+  uint32_t catchable_types;
+  // It is variable size but we only need the first element of this array
+  int32_t array_of_catchable_types[1];
+};
+
+struct EHThrowInfo {
+  uint32_t attributes;
+  int32_t unwind;
+  int32_t forward_compat;
+  int32_t catchable_type_array;
+};
+
+struct EHParameters {
+  uint32_t magic_number;
+  void* exception_object;
+  EHThrowInfo* throw_info;
+#ifdef _M_AMD64
+  uintptr_t throw_image_base;
+#endif
+};
+
+struct EHExceptionRecord {
+  uint32_t exception_code;
+  uint32_t exception_flags;
+  void* exception_record;
+  void* exception_address;
+  uint32_t number_of_parameters;
+  EHParameters parameters;
+};
+
+// defined in vcruntime<ver>.dll
+extern "C" EHExceptionRecord** __current_exception();
+
+// This is internal compiler definition for MSVC but not for clang.
+// We use our own EHThrowInfo because _ThrowInfo doesn't match actual
+// compiler-generated structures in 64-bit mode.
+#ifdef __clang__
+struct _ThrowInfo;
+// defined in vcruntime<ver>.dll
+_LIBCPP_NORETURN extern "C" void __stdcall _CxxThrowException(
+    void* __exc, _ThrowInfo* __throw_info);
+#endif
+
+namespace {
+struct ExceptionPtr {
+  void* exception_object;
+  const EHThrowInfo* throw_info;
+  std::atomic<size_t> counter;
+#ifdef _M_AMD64
+  PVOID image_base;
+#endif
+  template <class T>
+  T convert(int32_t offset) {
+#ifdef _M_AMD64
+    uintptr_t value = reinterpret_cast<uintptr_t>(image_base) +
+                      static_cast<uintptr_t>(offset);
+#else
+    uintptr_t value = static_cast<uintptr_t>(offset);
+#endif
+    T res;
+    static_assert(
+        sizeof(value) == sizeof(res),
+        "Can only convert to pointers or pointers to member functions");
+    memcpy(&res, &value, sizeof(value));
+    return res;
+  }
+
+  void copy(void* dst, const void* src, const EHCatchableType* exc_type) {
+    struct Temp {};
+    constexpr uint32_t virtual_base = 4;
+    if (exc_type->copy_function == 0) {
+      memcpy(dst, src, exc_type->size);
+    } else if (exc_type->properties & virtual_base) {
+      auto copy_constructor =
+          convert<void (Temp::*)(const void*, int)>(exc_type->copy_function);
+      ((Temp*)dst->*copy_constructor)(src, 1);
+    } else {
+      auto copy_constructor =
+          convert<void (Temp::*)(const void*)>(exc_type->copy_function);
+      ((Temp*)dst->*copy_constructor)(src);
+    }
+  }
+
+  EHCatchableType* exception_type() {
+    return convert<EHCatchableType*>(
+        convert<EHCatchableTypeArray*>(throw_info->catchable_type_array)
+            ->array_of_catchable_types[0]);
+  }
+
+  ExceptionPtr(const void* exception_object_, const EHThrowInfo* throw_info_)
+      : exception_object(nullptr), throw_info(throw_info_), counter(1) {
+#ifdef _M_AMD64
+    RtlPcToFileHeader(
+        reinterpret_cast<PVOID>(const_cast<EHThrowInfo*>(throw_info)),
+        &image_base);
+#endif
+    EHCatchableType* exc_type = exception_type();
+    this->exception_object = malloc(exc_type->size);
+    if (this->exception_object == nullptr) {
+      throw std::bad_alloc();
+    }
+    copy(exception_object, exception_object_, exc_type);
+  }
+
+  ~ExceptionPtr() {
+    if (throw_info->unwind && exception_object) {
+      struct Temp {};
+      auto destructor = convert<void (Temp::*)()>(throw_info->unwind);
+      ((Temp*)exception_object->*destructor)();
+    }
+    free(exception_object);
+  }
+
+  // _bad_alloc_storage must be initialized before bad_alloc, so we declare and define it first.
+  static std::bad_alloc _bad_alloc_storage;
+  static ExceptionPtr bad_alloc;
+  //static ExceptionPtr bad_exception;
+};
+
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Waddress-of-temporary"
+#endif
+
+std::bad_alloc ExceptionPtr::_bad_alloc_storage;
+
+ExceptionPtr ExceptionPtr::bad_alloc(
+    &ExceptionPtr::_bad_alloc_storage,
+    reinterpret_cast<const EHThrowInfo*>(__GetExceptionInfo(ExceptionPtr::_bad_alloc_storage)));
+
+/* ExceptionPtr
+ExceptionPtr::bad_exception(&std::bad_exception(),
+                            reinterpret_cast<const EHThrowInfo*>(
+                                __GetExceptionInfo(std::bad_exception()))); */
+
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
+
+} // namespace
+
+namespace std {
+
+exception_ptr::exception_ptr(const exception_ptr& __other) noexcept
+    : __ptr_(__other.__ptr_) {
+  if (__ptr_) {
+    reinterpret_cast<ExceptionPtr*>(__ptr_)->counter.fetch_add(1);
+  }
+}
+
+exception_ptr& exception_ptr::
+operator=(const exception_ptr& __other) noexcept {
+  auto before = __ptr_;
+  __ptr_ = __other.__ptr_;
+  if (__ptr_) {
+    reinterpret_cast<ExceptionPtr*>(__ptr_)->counter.fetch_add(1);
+  }
+  if (before) {
+    if (reinterpret_cast<ExceptionPtr*>(before)->counter.fetch_sub(1) == 1) {
+      delete reinterpret_cast<ExceptionPtr*>(before);
+    }
+  }
+  return *this;
+}
+
+exception_ptr::~exception_ptr() noexcept {
+  if (__ptr_) {
+    if (reinterpret_cast<ExceptionPtr*>(__ptr_)->counter.fetch_sub(1) == 1) {
+      delete reinterpret_cast<ExceptionPtr*>(__ptr_);
+    }
+  }
+}
+
+exception_ptr __copy_exception_ptr(void* exception_object,
+                                   const void* throw_info) {
+  ExceptionPtr* ptr;
+  try {
+    ptr = new ExceptionPtr(exception_object,
+                           reinterpret_cast<const EHThrowInfo*>(throw_info));
+  } catch (const std::bad_alloc&) {
+    ptr = &ExceptionPtr::bad_alloc;
+    ptr->counter.fetch_add(1);
+  } catch (...) {
+    //ptr = &ExceptionPtr::bad_exception;
+    //ptr->counter.fetch_add(1);
+    std::terminate();
+  }
+  exception_ptr res;
+  memcpy(&res, &ptr, sizeof(ptr));
+  return res;
+}
+
+exception_ptr current_exception() noexcept {
+  EHExceptionRecord** record = __current_exception();
+  if (*record && !std::uncaught_exception()) {
+    return __copy_exception_ptr((*record)->parameters.exception_object,
+                                (*record)->parameters.throw_info);
+  }
+  return exception_ptr();
+}
+
+_LIBCPP_NORETURN
+void rethrow_exception(exception_ptr p) {
+  if (!p) {
+    throw std::bad_exception();
+  }
+  ExceptionPtr* exc_ptr = reinterpret_cast<ExceptionPtr*>(p.__ptr_);
+  EHCatchableType* exc_type = exc_ptr->exception_type();
+  // _CxxThrowException doesn't call free on exception object so we must
+  // allocate it on the stack.
+  void* dst = _alloca(exc_type->size);
+  exc_ptr->copy(dst, exc_ptr->exception_object, exc_type);
+  auto throw_info = reinterpret_cast<_ThrowInfo*>(
+      const_cast<EHThrowInfo*>(exc_ptr->throw_info));
+  // For some reason clang doesn't call p destructor during unwinding.
+  // So we must clear it ourselves.
+  p = nullptr;
+  _CxxThrowException(dst, throw_info);
+}
+
+nested_exception::nested_exception() noexcept : __ptr_(current_exception()) {}
+
+nested_exception::~nested_exception() noexcept {}
+
+_LIBCPP_NORETURN
+void nested_exception::rethrow_nested() const {
+  if (__ptr_ == nullptr)
+    terminate();
+  rethrow_exception(__ptr_);
+}
+
+} // namespace std
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_pointer_unimplemented.ipp b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_pointer_unimplemented.ipp
new file mode 100644
index 00000000000..9e8ec04e119
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/runtime/exception_pointer_unimplemented.ipp
@@ -0,0 +1,79 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <stdio.h>
+#include <stdlib.h>
+
+namespace std {
+
+exception_ptr::~exception_ptr() noexcept
+{
+#  warning exception_ptr not yet implemented
+  fprintf(stderr, "exception_ptr not yet implemented\n");
+  ::abort();
+}
+
+exception_ptr::exception_ptr(const exception_ptr& other) noexcept
+    : __ptr_(other.__ptr_)
+{
+#  warning exception_ptr not yet implemented
+  fprintf(stderr, "exception_ptr not yet implemented\n");
+  ::abort();
+}
+
+exception_ptr& exception_ptr::operator=(const exception_ptr& other) noexcept
+{
+#  warning exception_ptr not yet implemented
+  fprintf(stderr, "exception_ptr not yet implemented\n");
+  ::abort();
+}
+
+nested_exception::nested_exception() noexcept
+    : __ptr_(current_exception())
+{
+}
+
+#if !defined(__GLIBCXX__)
+
+nested_exception::~nested_exception() noexcept
+{
+}
+
+#endif
+
+_LIBCPP_NORETURN
+void
+nested_exception::rethrow_nested() const
+{
+#  warning exception_ptr not yet implemented
+  fprintf(stderr, "exception_ptr not yet implemented\n");
+  ::abort();
+#if 0
+  if (__ptr_ == nullptr)
+      terminate();
+  rethrow_exception(__ptr_);
+#endif // FIXME
+}
+
+exception_ptr current_exception() noexcept
+{
+#  warning exception_ptr not yet implemented
+  fprintf(stderr, "exception_ptr not yet implemented\n");
+  ::abort();
+}
+
+_LIBCPP_NORETURN
+void rethrow_exception(exception_ptr p)
+{
+#  warning exception_ptr not yet implemented
+  fprintf(stderr, "exception_ptr not yet implemented\n");
+  ::abort();
+}
+
+} // namespace std
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/runtime/new_handler_fallback.ipp b/contrib/libs/cxxsupp/libcxx/src/support/runtime/new_handler_fallback.ipp
new file mode 100644
index 00000000000..3eaeb489a10
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/runtime/new_handler_fallback.ipp
@@ -0,0 +1,28 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "../../include/atomic_support.h"
+
+namespace std {
+
+_LIBCPP_SAFE_STATIC static std::new_handler __new_handler;
+
+new_handler
+set_new_handler(new_handler handler) noexcept
+{
+    return __libcpp_atomic_exchange(&__new_handler, handler);
+}
+
+new_handler
+get_new_handler() noexcept
+{
+    return __libcpp_atomic_load(&__new_handler);
+}
+
+} // namespace std
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/runtime/stdexcept_default.ipp b/contrib/libs/cxxsupp/libcxx/src/support/runtime/stdexcept_default.ipp
new file mode 100644
index 00000000000..5d22b7894c3
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/runtime/stdexcept_default.ipp
@@ -0,0 +1,64 @@
+//===--------------------- stdexcept_default.ipp --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "../../include/refstring.h"
+
+/* For _LIBCPPABI_VERSION */
+#if !defined(_LIBCPP_BUILDING_HAS_NO_ABI_LIBRARY) &&                           \
+    (defined(LIBCXX_BUILDING_LIBCXXABI) || defined(LIBCXX_BUILDING_LIBCXXRT))
+#include <cxxabi.h>
+#endif
+
+static_assert(sizeof(std::__libcpp_refstring) == sizeof(const char*), "");
+
+namespace std // purposefully not using versioning namespace
+{
+
+logic_error::logic_error(const string& msg) : __imp_(msg.c_str()) {}
+
+logic_error::logic_error(const char* msg) : __imp_(msg) {}
+
+logic_error::logic_error(const logic_error& le) noexcept : __imp_(le.__imp_) {}
+
+logic_error& logic_error::operator=(const logic_error& le) noexcept {
+  __imp_ = le.__imp_;
+  return *this;
+}
+
+runtime_error::runtime_error(const string& msg) : __imp_(msg.c_str()) {}
+
+runtime_error::runtime_error(const char* msg) : __imp_(msg) {}
+
+runtime_error::runtime_error(const runtime_error& re) noexcept
+    : __imp_(re.__imp_) {}
+
+runtime_error& runtime_error::operator=(const runtime_error& re) noexcept {
+  __imp_ = re.__imp_;
+  return *this;
+}
+
+#if !defined(_LIBCPPABI_VERSION) && !defined(LIBSTDCXX)
+
+const char* logic_error::what() const noexcept { return __imp_.c_str(); }
+
+const char* runtime_error::what() const noexcept { return __imp_.c_str(); }
+
+logic_error::~logic_error() noexcept {}
+domain_error::~domain_error() noexcept {}
+invalid_argument::~invalid_argument() noexcept {}
+length_error::~length_error() noexcept {}
+out_of_range::~out_of_range() noexcept {}
+
+runtime_error::~runtime_error() noexcept {}
+range_error::~range_error() noexcept {}
+overflow_error::~overflow_error() noexcept {}
+underflow_error::~underflow_error() noexcept {}
+
+#endif
+
+} // namespace std
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/runtime/stdexcept_vcruntime.ipp b/contrib/libs/cxxsupp/libcxx/src/support/runtime/stdexcept_vcruntime.ipp
new file mode 100644
index 00000000000..94eed465ae9
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/runtime/stdexcept_vcruntime.ipp
@@ -0,0 +1,16 @@
+//===------------------- stdexcept_vcruntime.ipp --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_ABI_VCRUNTIME
+#error This file may only be used when defering to vcruntime
+#endif
+
+namespace std {
+logic_error::logic_error(std::string const& s) : exception(s.c_str()) {}
+runtime_error::runtime_error(std::string const& s) : exception(s.c_str()) {}
+} // namespace std
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/solaris/README b/contrib/libs/cxxsupp/libcxx/src/support/solaris/README
new file mode 100644
index 00000000000..89c887a3b4a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/solaris/README
@@ -0,0 +1,4 @@
+This directory contains a partial implementation of the xlocale APIs for
+Solaris.  Some portions are lifted from FreeBSD libc, and so are covered by a
+2-clause BSD license instead of the MIT/UUIC license that the rest of libc++ is
+distributed under.
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/solaris/mbsnrtowcs.inc b/contrib/libs/cxxsupp/libcxx/src/support/solaris/mbsnrtowcs.inc
new file mode 100644
index 00000000000..074045277ca
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/solaris/mbsnrtowcs.inc
@@ -0,0 +1,76 @@
+
+
+/*-
+ * As noted in the source, some portions of this implementation are copied from
+ * FreeBSD libc.  These are covered by the following copyright:
+ *
+ * Copyright (c) 2002-2004 Tim J. Robbins.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+size_t
+mbsnrtowcs_l(wchar_t * __restrict dst, const char ** __restrict src,
+    size_t nms, size_t len, mbstate_t * __restrict ps, locale_t loc)
+{
+  const char *s;
+  size_t nchr;
+  wchar_t wc;
+  size_t nb;
+  FIX_LOCALE(loc);
+
+  s = *src;
+  nchr = 0;
+
+  if (dst == NULL) {
+    for (;;) {
+      if ((nb = mbrtowc_l(&wc, s, nms, ps, loc)) == (size_t)-1)
+        /* Invalid sequence - mbrtowc() sets errno. */
+        return ((size_t)-1);
+      else if (nb == 0 || nb == (size_t)-2)
+        return (nchr);
+      s += nb;
+      nms -= nb;
+      nchr++;
+    }
+    /*NOTREACHED*/
+  }
+
+  while (len-- > 0) {
+    if ((nb = mbrtowc_l(dst, s, nms, ps, loc)) == (size_t)-1) {
+      *src = s;
+      return ((size_t)-1);
+    } else if (nb == (size_t)-2) {
+      *src = s + nms;
+      return (nchr);
+    } else if (nb == 0) {
+      *src = NULL;
+      return (nchr);
+    }
+    s += nb;
+    nms -= nb;
+    nchr++;
+    dst++;
+  }
+  *src = s;
+  return (nchr);
+}
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/solaris/wcsnrtombs.inc b/contrib/libs/cxxsupp/libcxx/src/support/solaris/wcsnrtombs.inc
new file mode 100644
index 00000000000..239079e4719
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/solaris/wcsnrtombs.inc
@@ -0,0 +1,92 @@
+/*-
+ * Copyright (c) 2002-2004 Tim J. Robbins.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+
+size_t
+wcsnrtombs_l(char * __restrict dst, const wchar_t ** __restrict src,
+    size_t nwc, size_t len, mbstate_t * __restrict ps, locale_t loc)
+{
+  FIX_LOCALE(loc);
+  mbstate_t mbsbak;
+  char buf[MB_CUR_MAX_L(loc)];
+  const wchar_t *s;
+  size_t nbytes;
+  size_t nb;
+
+  s = *src;
+  nbytes = 0;
+
+  if (dst == NULL) {
+    while (nwc-- > 0) {
+      if ((nb = wcrtomb_l(buf, *s, ps, loc)) == (size_t)-1)
+        /* Invalid character - wcrtomb() sets errno. */
+        return ((size_t)-1);
+      else if (*s == L'\0')
+        return (nbytes + nb - 1);
+      s++;
+      nbytes += nb;
+    }
+    return (nbytes);
+  }
+
+  while (len > 0 && nwc-- > 0) {
+    if (len > (size_t)MB_CUR_MAX_L(loc)) {
+      /* Enough space to translate in-place. */
+      if ((nb = wcrtomb_l(dst, *s, ps, loc)) == (size_t)-1) {
+        *src = s;
+        return ((size_t)-1);
+      }
+    } else {
+      /*
+       * May not be enough space; use temp. buffer.
+       *
+       * We need to save a copy of the conversion state
+       * here so we can restore it if the multibyte
+       * character is too long for the buffer.
+       */
+      mbsbak = *ps;
+      if ((nb = wcrtomb_l(buf, *s, ps, loc)) == (size_t)-1) {
+        *src = s;
+        return ((size_t)-1);
+      }
+      if (nb > (int)len) {
+        /* MB sequence for character won't fit. */
+        *ps = mbsbak;
+        break;
+      }
+      memcpy(dst, buf, nb);
+    }
+    if (*s == L'\0') {
+      *src = NULL;
+      return (nbytes + nb - 1);
+    }
+    s++;
+    dst += nb;
+    len -= nb;
+    nbytes += nb;
+  }
+  *src = s;
+  return (nbytes);
+}
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/solaris/xlocale.cpp b/contrib/libs/cxxsupp/libcxx/src/support/solaris/xlocale.cpp
new file mode 100644
index 00000000000..d25adcd21d3
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/solaris/xlocale.cpp
@@ -0,0 +1,68 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifdef __sun__
+
+#include "__support/solaris/xlocale.h"
+#include <stdarg.h>
+#include <stdio.h>
+#include <sys/localedef.h>
+
+extern "C" {
+
+int isxdigit_l(int __c, locale_t __l) {
+    return isxdigit(__c);
+}
+
+int iswxdigit_l(wint_t __c, locale_t __l) {
+    return isxdigit(__c);
+}
+
+// FIXME: This disregards the locale, which is Very Wrong
+#define vsnprintf_l(__s, __n, __l, __format, __va)  \
+    vsnprintf(__s, __n, __format, __va)
+
+int snprintf_l(char *__s, size_t __n, locale_t __l, const char *__format, ...)
+{
+  va_list __va;
+  va_start(__va, __format);
+  int __res = vsnprintf_l(__s, __n , __l, __format, __va);
+  va_end(__va);
+  return __res;
+}
+
+int asprintf_l(char **__s, locale_t __l, const char *__format, ...) {
+  va_list __va;
+  va_start(__va, __format);
+  // FIXME:
+  int __res = vasprintf(__s, __format, __va);
+  va_end(__va);
+  return __res;
+}
+
+int sscanf_l(const char *__s, locale_t __l, const char *__format, ...) {
+  va_list __va;
+  va_start(__va, __format);
+  // FIXME:
+  int __res = vsscanf(__s, __format, __va);
+  va_end(__va);
+  return __res;
+}
+
+size_t mbrtowc_l(wchar_t *__pwc, const char *__pmb,
+                 size_t __max, mbstate_t *__ps, locale_t __loc) {
+  return mbrtowc(__pwc, __pmb, __max, __ps);
+}
+
+struct lconv *localeconv_l(locale_t __l) {
+  return localeconv();
+}
+
+};
+
+#endif // __sun__
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/win32/atomic_win32.cpp b/contrib/libs/cxxsupp/libcxx/src/support/win32/atomic_win32.cpp
new file mode 100644
index 00000000000..28cb0722ce7
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/win32/atomic_win32.cpp
@@ -0,0 +1,31 @@
+#include <intrin.h>
+#include <cstdint>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace {
+static const int __msvc_locks_size = 1024;
+volatile long __msvc_locks[__msvc_locks_size];
+
+size_t __msvc_lock_hash(void* __p) {
+    uintptr_t __num = reinterpret_cast<uintptr_t>(__p);
+    return (__num ^ (__num >> 10)) & (__msvc_locks_size - 1);
+}
+}
+
+void __msvc_lock(void* __p) {
+    volatile long& __lock = __msvc_locks[__msvc_lock_hash(__p)];
+    while (_InterlockedExchange(&__lock, 1) == 0) {
+#if defined(_M_ARM) || defined(_M_ARM64)
+        __yield();
+#endif
+    }
+}
+
+void __msvc_unlock(void* __p) {
+    volatile long& __lock = __msvc_locks[__msvc_lock_hash(__p)];
+    _InterlockedExchange(&__lock, 0);
+}
+
+_LIBCPP_END_NAMESPACE_STD
\ No newline at end of file
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/win32/locale_win32.cpp b/contrib/libs/cxxsupp/libcxx/src/support/win32/locale_win32.cpp
new file mode 100644
index 00000000000..f10916875d4
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/win32/locale_win32.cpp
@@ -0,0 +1,138 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <locale>
+#include <cstdarg> // va_start, va_end
+#include <memory>
+#include <type_traits>
+
+int __libcpp_vasprintf(char **sptr, const char *__restrict fmt, va_list ap);
+
+using std::__libcpp_locale_guard;
+
+// FIXME: base currently unused. Needs manual work to construct the new locale
+locale_t newlocale( int mask, const char * locale, locale_t /*base*/ )
+{
+    return {_create_locale( LC_ALL, locale ), locale};
+}
+
+decltype(MB_CUR_MAX) MB_CUR_MAX_L( locale_t __l )
+{
+#if defined(_LIBCPP_MSVCRT)
+  return ___mb_cur_max_l_func(__l);
+#else
+  __libcpp_locale_guard __current(__l);
+  return MB_CUR_MAX;
+#endif
+}
+
+lconv *localeconv_l( locale_t &loc )
+{
+    __libcpp_locale_guard __current(loc);
+    lconv *lc = localeconv();
+    if (!lc)
+        return lc;
+    return loc.__store_lconv(lc);
+}
+size_t mbrlen_l( const char *__restrict s, size_t n,
+                 mbstate_t *__restrict ps, locale_t loc )
+{
+    __libcpp_locale_guard __current(loc);
+    return mbrlen( s, n, ps );
+}
+size_t mbsrtowcs_l( wchar_t *__restrict dst, const char **__restrict src,
+                    size_t len, mbstate_t *__restrict ps, locale_t loc )
+{
+    __libcpp_locale_guard __current(loc);
+    return mbsrtowcs( dst, src, len, ps );
+}
+size_t wcrtomb_l( char *__restrict s, wchar_t wc, mbstate_t *__restrict ps,
+                  locale_t loc )
+{
+    __libcpp_locale_guard __current(loc);
+    return wcrtomb( s, wc, ps );
+}
+size_t mbrtowc_l( wchar_t *__restrict pwc, const char *__restrict s,
+                  size_t n, mbstate_t *__restrict ps, locale_t loc )
+{
+    __libcpp_locale_guard __current(loc);
+    return mbrtowc( pwc, s, n, ps );
+}
+size_t mbsnrtowcs_l( wchar_t *__restrict dst, const char **__restrict src,
+                     size_t nms, size_t len, mbstate_t *__restrict ps, locale_t loc )
+{
+    __libcpp_locale_guard __current(loc);
+    return mbsnrtowcs( dst, src, nms, len, ps );
+}
+size_t wcsnrtombs_l( char *__restrict dst, const wchar_t **__restrict src,
+                     size_t nwc, size_t len, mbstate_t *__restrict ps, locale_t loc )
+{
+    __libcpp_locale_guard __current(loc);
+    return wcsnrtombs( dst, src, nwc, len, ps );
+}
+wint_t btowc_l( int c, locale_t loc )
+{
+    __libcpp_locale_guard __current(loc);
+    return btowc( c );
+}
+int wctob_l( wint_t c, locale_t loc )
+{
+    __libcpp_locale_guard __current(loc);
+    return wctob( c );
+}
+
+int snprintf_l(char *ret, size_t n, locale_t loc, const char *format, ...)
+{
+    va_list ap;
+    va_start( ap, format );
+#if defined(_LIBCPP_MSVCRT)
+    // FIXME: Remove usage of internal CRT function and globals.
+    int result = __stdio_common_vsprintf(
+        _CRT_INTERNAL_LOCAL_PRINTF_OPTIONS | _CRT_INTERNAL_PRINTF_STANDARD_SNPRINTF_BEHAVIOR,
+        ret, n, format, loc, ap);
+#else
+    __libcpp_locale_guard __current(loc);
+    int result = vsnprintf( ret, n, format, ap );
+#endif
+    va_end(ap);
+    return result;
+}
+
+int asprintf_l( char **ret, locale_t loc, const char *format, ... )
+{
+    va_list ap;
+    va_start( ap, format );
+    int result = vasprintf_l( ret, loc, format, ap );
+    va_end(ap);
+    return result;
+}
+int vasprintf_l( char **ret, locale_t loc, const char *format, va_list ap )
+{
+    __libcpp_locale_guard __current(loc);
+    return __libcpp_vasprintf( ret, format, ap );
+}
+
+#if !defined(_LIBCPP_MSVCRT)
+float strtof_l(const char* nptr, char** endptr, locale_t loc) {
+  __libcpp_locale_guard __current(loc);
+  return strtof(nptr, endptr);
+}
+
+long double strtold_l(const char* nptr, char** endptr, locale_t loc) {
+  __libcpp_locale_guard __current(loc);
+  return strtold(nptr, endptr);
+}
+#endif
+
+#if defined(__MINGW32__) && __MSVCRT_VERSION__ < 0x0800
+size_t strftime_l(char *ret, size_t n, const char *format, const struct tm *tm,
+                  locale_t loc) {
+  __libcpp_locale_guard __current(loc);
+  return strftime(ret, n, format, tm);
+}
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/win32/new_win32.cpp b/contrib/libs/cxxsupp/libcxx/src/support/win32/new_win32.cpp
new file mode 100644
index 00000000000..00eff4abf9d
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/win32/new_win32.cpp
@@ -0,0 +1,28 @@
+#include <atomic>
+#include <new>
+
+namespace std {
+
+void
+__throw_bad_alloc()
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw bad_alloc();
+#endif
+}
+
+static std::atomic<std::new_handler> __new_handler;
+
+new_handler
+set_new_handler(new_handler handler) _NOEXCEPT
+{
+    return __new_handler.exchange(handler);
+}
+
+new_handler
+get_new_handler() _NOEXCEPT
+{
+    return __new_handler.load();
+}
+
+}
\ No newline at end of file
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/win32/support.cpp b/contrib/libs/cxxsupp/libcxx/src/support/win32/support.cpp
new file mode 100644
index 00000000000..11702a788b1
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/win32/support.cpp
@@ -0,0 +1,166 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <cstdarg> // va_start, va_end
+#include <cstddef> // size_t
+#include <cstdlib> // malloc
+#include <cstdio>  // vsprintf, vsnprintf
+#include <cstring> // strcpy, wcsncpy
+#include <cwchar>  // mbstate_t
+
+
+// Like sprintf, but when return value >= 0 it returns
+// a pointer to a malloc'd string in *sptr.
+// If return >= 0, use free to delete *sptr.
+int __libcpp_vasprintf( char **sptr, const char *__restrict format, va_list ap )
+{
+    *sptr = NULL;
+    // Query the count required.
+    va_list ap_copy;
+    va_copy(ap_copy, ap);
+    int count = _vsnprintf( NULL, 0, format, ap_copy );
+    va_end(ap_copy);
+    if (count < 0)
+        return count;
+    size_t buffer_size = static_cast<size_t>(count) + 1;
+    char* p = static_cast<char*>(malloc(buffer_size));
+    if ( ! p )
+        return -1;
+    // If we haven't used exactly what was required, something is wrong.
+    // Maybe bug in vsnprintf. Report the error and return.
+    if (_vsnprintf(p, buffer_size, format, ap) != count) {
+        free(p);
+        return -1;
+    }
+    // All good. This is returning memory to the caller not freeing it.
+    *sptr = p;
+    return count;
+}
+
+// Returns >= 0: the number of wide characters found in the
+// multi byte sequence src (of src_size_bytes), that fit in the buffer dst
+// (of max_dest_chars elements size). The count returned excludes the
+// null terminator. When dst is NULL, no characters are copied
+// and no "out" parameters are updated.
+// Returns (size_t) -1: an incomplete sequence encountered.
+// Leaves *src pointing the next character to convert or NULL
+// if a null character was converted from *src.
+size_t mbsnrtowcs( wchar_t *__restrict dst, const char **__restrict src,
+                   size_t src_size_bytes, size_t max_dest_chars, mbstate_t *__restrict ps )
+{
+    const size_t terminated_sequence = static_cast<size_t>(0);
+    //const size_t invalid_sequence = static_cast<size_t>(-1);
+    const size_t incomplete_sequence = static_cast< size_t>(-2);
+
+    size_t dest_converted = 0;
+    size_t source_converted = 0;
+    size_t source_remaining = src_size_bytes;
+    size_t result = 0;
+    bool have_result = false;
+
+    // If dst is null then max_dest_chars should be ignored according to the
+    // standard.  Setting max_dest_chars to a large value has this effect.
+    if (!dst)
+        max_dest_chars = static_cast<size_t>(-1);
+
+    while ( source_remaining ) {
+        if ( dst && dest_converted >= max_dest_chars )
+            break;
+        // Converts one multi byte character.
+        // if result > 0, it's the size in bytes of that character.
+        // othewise if result is zero it indicates the null character has been found.
+        // otherwise it's an error and errno may be set.
+        size_t char_size = mbrtowc( dst ? dst + dest_converted : NULL, *src + source_converted, source_remaining, ps );
+        // Don't do anything to change errno from here on.
+        if ( char_size > 0 ) {
+            source_remaining -= char_size;
+            source_converted += char_size;
+            ++dest_converted;
+            continue;
+        }
+        result = char_size;
+        have_result = true;
+        break;
+    }
+    if ( dst ) {
+        if ( have_result && result == terminated_sequence )
+            *src = NULL;
+        else
+            *src += source_converted;
+    }
+    if ( have_result && result != terminated_sequence && result != incomplete_sequence )
+        return static_cast<size_t>(-1);
+
+    return dest_converted;
+}
+
+// Converts max_source_chars from the wide character buffer pointer to by *src,
+// into the multi byte character sequence buffer stored at dst which must be
+// dst_size_bytes bytes in size.
+// Returns >= 0: the number of bytes in the sequence
+// converted from *src, excluding the null terminator.
+// Returns size_t(-1) if an error occurs, also sets errno.
+// If dst is NULL dst_size_bytes is ignored and no bytes are copied to dst
+// and no "out" parameters are updated.
+size_t wcsnrtombs( char *__restrict dst, const wchar_t **__restrict src,
+                   size_t max_source_chars, size_t dst_size_bytes, mbstate_t *__restrict ps )
+{
+    //const size_t invalid_sequence = static_cast<size_t>(-1);
+
+    size_t source_converted = 0;
+    size_t dest_converted = 0;
+    size_t dest_remaining = dst_size_bytes;
+    size_t char_size = 0;
+    const errno_t no_error = ( errno_t) 0;
+    errno_t result = ( errno_t ) 0;
+    bool have_result = false;
+    bool terminator_found = false;
+
+    // If dst is null then dst_size_bytes should be ignored according to the
+    // standard.  Setting dest_remaining to a large value has this effect.
+    if (!dst)
+        dest_remaining = static_cast<size_t>(-1);
+
+    while ( source_converted != max_source_chars ) {
+        if ( ! dest_remaining )
+            break;
+        wchar_t c = (*src)[source_converted];
+        if ( dst )
+            result = wcrtomb_s( &char_size, dst + dest_converted, dest_remaining, c, ps);
+        else
+            result = wcrtomb_s( &char_size, NULL, 0, c, ps);
+        // If result is zero there is no error and char_size contains the
+        // size of the multi-byte-sequence converted.
+        // Otherwise result indicates an errno type error.
+        if ( result == no_error ) {
+            if ( c == L'\0' ) {
+                terminator_found = true;
+                break;
+            }
+            ++source_converted;
+            if ( dst )
+                dest_remaining -= char_size;
+            dest_converted += char_size;
+            continue;
+        }
+        have_result = true;
+        break;
+    }
+    if ( dst ) {
+        if ( terminator_found )
+            *src = NULL;
+        else
+            *src = *src + source_converted;
+    }
+    if ( have_result && result != no_error ) {
+        errno = result;
+        return static_cast<size_t>(-1);
+    }
+
+    return dest_converted;
+}
diff --git a/contrib/libs/cxxsupp/libcxx/src/support/win32/thread_win32.cpp b/contrib/libs/cxxsupp/libcxx/src/support/win32/thread_win32.cpp
new file mode 100644
index 00000000000..9506822da82
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/support/win32/thread_win32.cpp
@@ -0,0 +1,310 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <__threading_support>
+#define NOMINMAX
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <process.h>
+#include <fibersapi.h>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+static_assert(sizeof(__libcpp_mutex_t) == sizeof(SRWLOCK), "");
+static_assert(alignof(__libcpp_mutex_t) == alignof(SRWLOCK), "");
+
+static_assert(sizeof(__libcpp_recursive_mutex_t) == sizeof(CRITICAL_SECTION),
+              "");
+static_assert(alignof(__libcpp_recursive_mutex_t) == alignof(CRITICAL_SECTION),
+              "");
+
+static_assert(sizeof(__libcpp_condvar_t) == sizeof(CONDITION_VARIABLE), "");
+static_assert(alignof(__libcpp_condvar_t) == alignof(CONDITION_VARIABLE), "");
+
+static_assert(sizeof(__libcpp_exec_once_flag) == sizeof(INIT_ONCE), "");
+static_assert(alignof(__libcpp_exec_once_flag) == alignof(INIT_ONCE), "");
+
+static_assert(sizeof(__libcpp_thread_id) == sizeof(DWORD), "");
+static_assert(alignof(__libcpp_thread_id) == alignof(DWORD), "");
+
+static_assert(sizeof(__libcpp_thread_t) == sizeof(HANDLE), "");
+static_assert(alignof(__libcpp_thread_t) == alignof(HANDLE), "");
+
+static_assert(sizeof(__libcpp_tls_key) == sizeof(DWORD), "");
+static_assert(alignof(__libcpp_tls_key) == alignof(DWORD), "");
+
+static_assert(sizeof(__libcpp_semaphore_t) == sizeof(HANDLE), "");
+static_assert(alignof(__libcpp_semaphore_t) == alignof(HANDLE), "");
+
+// Mutex
+int __libcpp_recursive_mutex_init(__libcpp_recursive_mutex_t *__m)
+{
+  InitializeCriticalSection((LPCRITICAL_SECTION)__m);
+  return 0;
+}
+
+int __libcpp_recursive_mutex_lock(__libcpp_recursive_mutex_t *__m)
+{
+  EnterCriticalSection((LPCRITICAL_SECTION)__m);
+  return 0;
+}
+
+bool __libcpp_recursive_mutex_trylock(__libcpp_recursive_mutex_t *__m)
+{
+  return TryEnterCriticalSection((LPCRITICAL_SECTION)__m) != 0;
+}
+
+int __libcpp_recursive_mutex_unlock(__libcpp_recursive_mutex_t *__m)
+{
+  LeaveCriticalSection((LPCRITICAL_SECTION)__m);
+  return 0;
+}
+
+int __libcpp_recursive_mutex_destroy(__libcpp_recursive_mutex_t *__m)
+{
+  DeleteCriticalSection((LPCRITICAL_SECTION)__m);
+  return 0;
+}
+
+int __libcpp_mutex_lock(__libcpp_mutex_t *__m)
+{
+  AcquireSRWLockExclusive((PSRWLOCK)__m);
+  return 0;
+}
+
+bool __libcpp_mutex_trylock(__libcpp_mutex_t *__m)
+{
+  return TryAcquireSRWLockExclusive((PSRWLOCK)__m) != 0;
+}
+
+int __libcpp_mutex_unlock(__libcpp_mutex_t *__m)
+{
+  ReleaseSRWLockExclusive((PSRWLOCK)__m);
+  return 0;
+}
+
+int __libcpp_mutex_destroy(__libcpp_mutex_t *__m)
+{
+  static_cast<void>(__m);
+  return 0;
+}
+
+// Condition Variable
+int __libcpp_condvar_signal(__libcpp_condvar_t *__cv)
+{
+  WakeConditionVariable((PCONDITION_VARIABLE)__cv);
+  return 0;
+}
+
+int __libcpp_condvar_broadcast(__libcpp_condvar_t *__cv)
+{
+  WakeAllConditionVariable((PCONDITION_VARIABLE)__cv);
+  return 0;
+}
+
+int __libcpp_condvar_wait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m)
+{
+  SleepConditionVariableSRW((PCONDITION_VARIABLE)__cv, (PSRWLOCK)__m, INFINITE, 0);
+  return 0;
+}
+
+int __libcpp_condvar_timedwait(__libcpp_condvar_t *__cv, __libcpp_mutex_t *__m,
+                               __libcpp_timespec_t *__ts)
+{
+  using namespace _VSTD::chrono;
+
+  auto duration = seconds(__ts->tv_sec) + nanoseconds(__ts->tv_nsec);
+  auto abstime =
+      system_clock::time_point(duration_cast<system_clock::duration>(duration));
+  auto timeout_ms = duration_cast<milliseconds>(abstime - system_clock::now());
+
+  if (!SleepConditionVariableSRW((PCONDITION_VARIABLE)__cv, (PSRWLOCK)__m,
+                                 timeout_ms.count() > 0 ? timeout_ms.count()
+                                                        : 0,
+                                 0))
+    {
+      auto __ec = GetLastError();
+      return __ec == ERROR_TIMEOUT ? ETIMEDOUT : __ec;
+    }
+  return 0;
+}
+
+int __libcpp_condvar_destroy(__libcpp_condvar_t *__cv)
+{
+  static_cast<void>(__cv);
+  return 0;
+}
+
+// Execute Once
+static inline _LIBCPP_INLINE_VISIBILITY BOOL CALLBACK
+__libcpp_init_once_execute_once_thunk(PINIT_ONCE __init_once, PVOID __parameter,
+                                      PVOID *__context)
+{
+  static_cast<void>(__init_once);
+  static_cast<void>(__context);
+
+  void (*init_routine)(void) = reinterpret_cast<void (*)(void)>(__parameter);
+  init_routine();
+  return TRUE;
+}
+
+int __libcpp_execute_once(__libcpp_exec_once_flag *__flag,
+                          void (*__init_routine)(void))
+{
+  if (!InitOnceExecuteOnce((PINIT_ONCE)__flag, __libcpp_init_once_execute_once_thunk,
+                           reinterpret_cast<void *>(__init_routine), NULL))
+    return GetLastError();
+  return 0;
+}
+
+// Thread ID
+bool __libcpp_thread_id_equal(__libcpp_thread_id __lhs,
+                              __libcpp_thread_id __rhs)
+{
+  return __lhs == __rhs;
+}
+
+bool __libcpp_thread_id_less(__libcpp_thread_id __lhs, __libcpp_thread_id __rhs)
+{
+  return __lhs < __rhs;
+}
+
+// Thread
+struct __libcpp_beginthreadex_thunk_data
+{
+  void *(*__func)(void *);
+  void *__arg;
+};
+
+static inline _LIBCPP_INLINE_VISIBILITY unsigned WINAPI
+__libcpp_beginthreadex_thunk(void *__raw_data)
+{
+  auto *__data =
+      static_cast<__libcpp_beginthreadex_thunk_data *>(__raw_data);
+  auto *__func = __data->__func;
+  void *__arg = __data->__arg;
+  delete __data;
+  return static_cast<unsigned>(reinterpret_cast<uintptr_t>(__func(__arg)));
+}
+
+bool __libcpp_thread_isnull(const __libcpp_thread_t *__t) {
+  return *__t == 0;
+}
+
+int __libcpp_thread_create(__libcpp_thread_t *__t, void *(*__func)(void *),
+                           void *__arg)
+{
+  auto *__data = new __libcpp_beginthreadex_thunk_data;
+  __data->__func = __func;
+  __data->__arg = __arg;
+
+  *__t = reinterpret_cast<HANDLE>(_beginthreadex(nullptr, 0,
+                                                 __libcpp_beginthreadex_thunk,
+                                                 __data, 0, nullptr));
+
+  if (*__t)
+    return 0;
+  return GetLastError();
+}
+
+__libcpp_thread_id __libcpp_thread_get_current_id()
+{
+  return GetCurrentThreadId();
+}
+
+__libcpp_thread_id __libcpp_thread_get_id(const __libcpp_thread_t *__t)
+{
+  return GetThreadId(*__t);
+}
+
+int __libcpp_thread_join(__libcpp_thread_t *__t)
+{
+  if (WaitForSingleObjectEx(*__t, INFINITE, FALSE) == WAIT_FAILED)
+    return GetLastError();
+  if (!CloseHandle(*__t))
+    return GetLastError();
+  return 0;
+}
+
+int __libcpp_thread_detach(__libcpp_thread_t *__t)
+{
+  if (!CloseHandle(*__t))
+    return GetLastError();
+  return 0;
+}
+
+void __libcpp_thread_yield()
+{
+  SwitchToThread();
+}
+
+void __libcpp_thread_sleep_for(const chrono::nanoseconds& __ns)
+{
+  // round-up to the nearest millisecond
+  chrono::milliseconds __ms = chrono::ceil<chrono::milliseconds>(__ns);
+  // FIXME(compnerd) this should be an alertable sleep (WFSO or SleepEx)
+  Sleep(__ms.count());
+}
+
+// Thread Local Storage
+int __libcpp_tls_create(__libcpp_tls_key* __key,
+                        void(_LIBCPP_TLS_DESTRUCTOR_CC* __at_exit)(void*))
+{
+  DWORD index = FlsAlloc(__at_exit);
+  if (index == FLS_OUT_OF_INDEXES)
+    return GetLastError();
+  *__key = index;
+  return 0;
+}
+
+void *__libcpp_tls_get(__libcpp_tls_key __key)
+{
+  return FlsGetValue(__key);
+}
+
+int __libcpp_tls_set(__libcpp_tls_key __key, void *__p)
+{
+  if (!FlsSetValue(__key, __p))
+    return GetLastError();
+  return 0;
+}
+
+// Semaphores
+bool __libcpp_semaphore_init(__libcpp_semaphore_t* __sem, int __init)
+{
+  *(PHANDLE)__sem = CreateSemaphoreEx(nullptr, __init, _LIBCPP_SEMAPHORE_MAX,
+                                      nullptr, 0, SEMAPHORE_ALL_ACCESS);
+  return *__sem != nullptr;
+}
+
+bool __libcpp_semaphore_destroy(__libcpp_semaphore_t* __sem)
+{
+  CloseHandle(*(PHANDLE)__sem);
+  return true;
+}
+
+bool __libcpp_semaphore_post(__libcpp_semaphore_t* __sem)
+{
+  return ReleaseSemaphore(*(PHANDLE)__sem, 1, nullptr);
+}
+
+bool __libcpp_semaphore_wait(__libcpp_semaphore_t* __sem)
+{
+  return WaitForSingleObjectEx(*(PHANDLE)__sem, INFINITE, false) ==
+         WAIT_OBJECT_0;
+}
+
+bool __libcpp_semaphore_wait_timed(__libcpp_semaphore_t* __sem,
+                                   chrono::nanoseconds const& __ns)
+{
+  chrono::milliseconds __ms = chrono::ceil<chrono::milliseconds>(__ns);
+  return WaitForSingleObjectEx(*(PHANDLE)__sem, __ms.count(), false) ==
+         WAIT_OBJECT_0;
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/system_error.cpp b/contrib/libs/cxxsupp/libcxx/src/system_error.cpp
new file mode 100644
index 00000000000..a1ea6c4754e
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/system_error.cpp
@@ -0,0 +1,295 @@
+//===---------------------- system_error.cpp ------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "__config"
+
+#include "system_error"
+
+#include "include/config_elast.h"
+#include "cerrno"
+#include "cstring"
+#include "cstdio"
+#include "cstdlib"
+#include "string"
+#include "string.h"
+#include "__debug"
+
+#if defined(__ANDROID__)
+#include <android/api-level.h>
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// class error_category
+
+#if defined(_LIBCPP_DEPRECATED_ABI_LEGACY_LIBRARY_DEFINITIONS_FOR_INLINE_FUNCTIONS)
+error_category::error_category() noexcept
+{
+}
+#endif
+
+error_category::~error_category() noexcept
+{
+}
+
+error_condition
+error_category::default_error_condition(int ev) const noexcept
+{
+    return error_condition(ev, *this);
+}
+
+bool
+error_category::equivalent(int code, const error_condition& condition) const noexcept
+{
+    return default_error_condition(code) == condition;
+}
+
+bool
+error_category::equivalent(const error_code& code, int condition) const noexcept
+{
+    return *this == code.category() && code.value() == condition;
+}
+
+#if !defined(_LIBCPP_HAS_NO_THREADS)
+namespace {
+
+//  GLIBC also uses 1024 as the maximum buffer size internally.
+constexpr size_t strerror_buff_size = 1024;
+
+string do_strerror_r(int ev);
+
+#if defined(_LIBCPP_MSVCRT_LIKE)
+string do_strerror_r(int ev) {
+  char buffer[strerror_buff_size];
+  if (::strerror_s(buffer, strerror_buff_size, ev) == 0)
+    return string(buffer);
+  std::snprintf(buffer, strerror_buff_size, "unknown error %d", ev);
+  return string(buffer);
+}
+#else
+
+// Only one of the two following functions will be used, depending on
+// the return type of strerror_r:
+
+// For the GNU variant, a char* return value:
+__attribute__((unused)) const char *
+handle_strerror_r_return(char *strerror_return, char *buffer) {
+  // GNU always returns a string pointer in its return value. The
+  // string might point to either the input buffer, or a static
+  // buffer, but we don't care which.
+  return strerror_return;
+}
+
+// For the POSIX variant: an int return value.
+__attribute__((unused)) const char *
+handle_strerror_r_return(int strerror_return, char *buffer) {
+  // The POSIX variant either:
+  // - fills in the provided buffer and returns 0
+  // - returns a positive error value, or
+  // - returns -1 and fills in errno with an error value.
+  if (strerror_return == 0)
+    return buffer;
+
+  // Only handle EINVAL. Other errors abort.
+  int new_errno = strerror_return == -1 ? errno : strerror_return;
+  if (new_errno == EINVAL)
+    return "";
+
+  _LIBCPP_ASSERT(new_errno == ERANGE, "unexpected error from ::strerror_r");
+  // FIXME maybe? 'strerror_buff_size' is likely to exceed the
+  // maximum error size so ERANGE shouldn't be returned.
+  std::abort();
+}
+
+// This function handles both GNU and POSIX variants, dispatching to
+// one of the two above functions.
+string do_strerror_r(int ev) {
+    char buffer[strerror_buff_size];
+    // Preserve errno around the call. (The C++ standard requires that
+    // system_error functions not modify errno).
+    const int old_errno = errno;
+    const char *error_message = handle_strerror_r_return(
+        ::strerror_r(ev, buffer, strerror_buff_size), buffer);
+    // If we didn't get any message, print one now.
+    if (!error_message[0]) {
+      std::snprintf(buffer, strerror_buff_size, "Unknown error %d", ev);
+      error_message = buffer;
+    }
+    errno = old_errno;
+    return string(error_message);
+}
+#endif
+} // end namespace
+#endif
+
+string
+__do_message::message(int ev) const
+{
+#if defined(_LIBCPP_HAS_NO_THREADS)
+    return string(::strerror(ev));
+#else
+    return do_strerror_r(ev);
+#endif
+}
+
+class _LIBCPP_HIDDEN __generic_error_category
+    : public __do_message
+{
+public:
+    virtual const char* name() const noexcept;
+    virtual string message(int ev) const;
+};
+
+const char*
+__generic_error_category::name() const noexcept
+{
+    return "generic";
+}
+
+string
+__generic_error_category::message(int ev) const
+{
+#ifdef _LIBCPP_ELAST
+    if (ev > _LIBCPP_ELAST)
+      return string("unspecified generic_category error");
+#endif // _LIBCPP_ELAST
+    return __do_message::message(ev);
+}
+
+const error_category&
+generic_category() noexcept
+{
+    static __generic_error_category s;
+    return s;
+}
+
+class _LIBCPP_HIDDEN __system_error_category
+    : public __do_message
+{
+public:
+    virtual const char* name() const noexcept;
+    virtual string message(int ev) const;
+    virtual error_condition default_error_condition(int ev) const noexcept;
+};
+
+const char*
+__system_error_category::name() const noexcept
+{
+    return "system";
+}
+
+string
+__system_error_category::message(int ev) const
+{
+#ifdef _LIBCPP_ELAST
+    if (ev > _LIBCPP_ELAST)
+      return string("unspecified system_category error");
+#endif // _LIBCPP_ELAST
+    return __do_message::message(ev);
+}
+
+error_condition
+__system_error_category::default_error_condition(int ev) const noexcept
+{
+#ifdef _LIBCPP_ELAST
+    if (ev > _LIBCPP_ELAST)
+      return error_condition(ev, system_category());
+#endif // _LIBCPP_ELAST
+    return error_condition(ev, generic_category());
+}
+
+const error_category&
+system_category() noexcept
+{
+    static __system_error_category s;
+    return s;
+}
+
+// error_condition
+
+string
+error_condition::message() const
+{
+    return __cat_->message(__val_);
+}
+
+// error_code
+
+string
+error_code::message() const
+{
+    return __cat_->message(__val_);
+}
+
+// system_error
+
+string
+system_error::__init(const error_code& ec, string what_arg)
+{
+    if (ec)
+    {
+        if (!what_arg.empty())
+            what_arg += ": ";
+        what_arg += ec.message();
+    }
+    return what_arg;
+}
+
+system_error::system_error(error_code ec, const string& what_arg)
+    : runtime_error(__init(ec, what_arg)),
+      __ec_(ec)
+{
+}
+
+system_error::system_error(error_code ec, const char* what_arg)
+    : runtime_error(__init(ec, what_arg)),
+      __ec_(ec)
+{
+}
+
+system_error::system_error(error_code ec)
+    : runtime_error(__init(ec, "")),
+      __ec_(ec)
+{
+}
+
+system_error::system_error(int ev, const error_category& ecat, const string& what_arg)
+    : runtime_error(__init(error_code(ev, ecat), what_arg)),
+      __ec_(error_code(ev, ecat))
+{
+}
+
+system_error::system_error(int ev, const error_category& ecat, const char* what_arg)
+    : runtime_error(__init(error_code(ev, ecat), what_arg)),
+      __ec_(error_code(ev, ecat))
+{
+}
+
+system_error::system_error(int ev, const error_category& ecat)
+    : runtime_error(__init(error_code(ev, ecat), "")),
+      __ec_(error_code(ev, ecat))
+{
+}
+
+system_error::~system_error() noexcept
+{
+}
+
+void
+__throw_system_error(int ev, const char* what_arg)
+{
+#ifndef _LIBCPP_NO_EXCEPTIONS
+    throw system_error(error_code(ev, system_category()), what_arg);
+#else
+    (void)ev;
+    (void)what_arg;
+    _VSTD::abort();
+#endif
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/thread.cpp b/contrib/libs/cxxsupp/libcxx/src/thread.cpp
new file mode 100644
index 00000000000..8dddb240b5a
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/thread.cpp
@@ -0,0 +1,211 @@
+//===------------------------- thread.cpp----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "__config"
+#ifndef _LIBCPP_HAS_NO_THREADS
+
+#include "thread"
+#include "exception"
+#include "vector"
+#include "future"
+#include "limits"
+
+#if __has_include(<unistd.h>)
+# include <unistd.h> // for sysconf
+#endif
+
+#if defined(__NetBSD__)
+#pragma weak pthread_create // Do not create libpthread dependency
+#endif
+
+#if defined(_LIBCPP_WIN32API)
+#include <windows.h>
+#endif
+
+#if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
+#pragma comment(lib, "pthread")
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+thread::~thread()
+{
+    if (!__libcpp_thread_isnull(&__t_))
+        terminate();
+}
+
+void
+thread::join()
+{
+    int ec = EINVAL;
+    if (!__libcpp_thread_isnull(&__t_))
+    {
+        ec = __libcpp_thread_join(&__t_);
+        if (ec == 0)
+            __t_ = _LIBCPP_NULL_THREAD;
+    }
+
+    if (ec)
+        __throw_system_error(ec, "thread::join failed");
+}
+
+void
+thread::detach()
+{
+    int ec = EINVAL;
+    if (!__libcpp_thread_isnull(&__t_))
+    {
+        ec = __libcpp_thread_detach(&__t_);
+        if (ec == 0)
+            __t_ = _LIBCPP_NULL_THREAD;
+    }
+
+    if (ec)
+        __throw_system_error(ec, "thread::detach failed");
+}
+
+unsigned
+thread::hardware_concurrency() noexcept
+{
+#if defined(_SC_NPROCESSORS_ONLN)
+    long result = sysconf(_SC_NPROCESSORS_ONLN);
+    // sysconf returns -1 if the name is invalid, the option does not exist or
+    // does not have a definite limit.
+    // if sysconf returns some other negative number, we have no idea
+    // what is going on. Default to something safe.
+    if (result < 0)
+        return 0;
+    return static_cast<unsigned>(result);
+#elif defined(_LIBCPP_WIN32API)
+    SYSTEM_INFO info;
+    GetSystemInfo(&info);
+    return info.dwNumberOfProcessors;
+#else  // defined(CTL_HW) && defined(HW_NCPU)
+    // TODO: grovel through /proc or check cpuid on x86 and similar
+    // instructions on other architectures.
+#   if defined(_LIBCPP_WARNING)
+        _LIBCPP_WARNING("hardware_concurrency not yet implemented")
+#   else
+#       warning hardware_concurrency not yet implemented
+#   endif
+    return 0;  // Means not computable [thread.thread.static]
+#endif // defined(CTL_HW) && defined(HW_NCPU)
+}
+
+namespace this_thread
+{
+
+void
+sleep_for(const chrono::nanoseconds& ns)
+{
+    if (ns > chrono::nanoseconds::zero())
+    {
+        __libcpp_thread_sleep_for(ns);
+    }
+}
+
+}  // this_thread
+
+__thread_specific_ptr<__thread_struct>&
+__thread_local_data()
+{
+    static __thread_specific_ptr<__thread_struct> __p;
+    return __p;
+}
+
+// __thread_struct_imp
+
+template <class T>
+class _LIBCPP_HIDDEN __hidden_allocator
+{
+public:
+    typedef T  value_type;
+
+    T* allocate(size_t __n)
+        {return static_cast<T*>(::operator new(__n * sizeof(T)));}
+    void deallocate(T* __p, size_t) {::operator delete(static_cast<void*>(__p));}
+
+    size_t max_size() const {return size_t(~0) / sizeof(T);}
+};
+
+class _LIBCPP_HIDDEN __thread_struct_imp
+{
+    typedef vector<__assoc_sub_state*,
+                          __hidden_allocator<__assoc_sub_state*> > _AsyncStates;
+    typedef vector<pair<condition_variable*, mutex*>,
+               __hidden_allocator<pair<condition_variable*, mutex*> > > _Notify;
+
+    _AsyncStates async_states_;
+    _Notify notify_;
+
+    __thread_struct_imp(const __thread_struct_imp&);
+    __thread_struct_imp& operator=(const __thread_struct_imp&);
+public:
+    __thread_struct_imp() {}
+    ~__thread_struct_imp();
+
+    void notify_all_at_thread_exit(condition_variable* cv, mutex* m);
+    void __make_ready_at_thread_exit(__assoc_sub_state* __s);
+};
+
+__thread_struct_imp::~__thread_struct_imp()
+{
+    for (_Notify::iterator i = notify_.begin(), e = notify_.end();
+            i != e; ++i)
+    {
+        i->second->unlock();
+        i->first->notify_all();
+    }
+    for (_AsyncStates::iterator i = async_states_.begin(), e = async_states_.end();
+            i != e; ++i)
+    {
+        (*i)->__make_ready();
+        (*i)->__release_shared();
+    }
+}
+
+void
+__thread_struct_imp::notify_all_at_thread_exit(condition_variable* cv, mutex* m)
+{
+    notify_.push_back(pair<condition_variable*, mutex*>(cv, m));
+}
+
+void
+__thread_struct_imp::__make_ready_at_thread_exit(__assoc_sub_state* __s)
+{
+    async_states_.push_back(__s);
+    __s->__add_shared();
+}
+
+// __thread_struct
+
+__thread_struct::__thread_struct()
+    : __p_(new __thread_struct_imp)
+{
+}
+
+__thread_struct::~__thread_struct()
+{
+    delete __p_;
+}
+
+void
+__thread_struct::notify_all_at_thread_exit(condition_variable* cv, mutex* m)
+{
+    __p_->notify_all_at_thread_exit(cv, m);
+}
+
+void
+__thread_struct::__make_ready_at_thread_exit(__assoc_sub_state* __s)
+{
+    __p_->__make_ready_at_thread_exit(__s);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !_LIBCPP_HAS_NO_THREADS
diff --git a/contrib/libs/cxxsupp/libcxx/src/typeinfo.cpp b/contrib/libs/cxxsupp/libcxx/src/typeinfo.cpp
new file mode 100644
index 00000000000..baace5643c6
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/typeinfo.cpp
@@ -0,0 +1,57 @@
+//===------------------------- typeinfo.cpp -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "typeinfo"
+
+#if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_ABI_VCRUNTIME)
+#include <string.h>
+
+int std::type_info::__compare(const type_info &__rhs) const noexcept {
+  if (&__data == &__rhs.__data)
+    return 0;
+  return strcmp(&__data.__decorated_name[1], &__rhs.__data.__decorated_name[1]);
+}
+
+const char *std::type_info::name() const noexcept {
+  // TODO(compnerd) cache demangled &__data.__decorated_name[1]
+  return &__data.__decorated_name[1];
+}
+
+size_t std::type_info::hash_code() const noexcept {
+#if defined(_WIN64)
+  constexpr size_t fnv_offset_basis = 14695981039346656037ull;
+  constexpr size_t fnv_prime = 10995116282110ull;
+#else
+  constexpr size_t fnv_offset_basis = 2166136261ull;
+  constexpr size_t fnv_prime = 16777619ull;
+#endif
+
+  size_t value = fnv_offset_basis;
+  for (const char* c = &__data.__decorated_name[1]; *c; ++c) {
+    value ^= static_cast<size_t>(static_cast<unsigned char>(*c));
+    value *= fnv_prime;
+  }
+
+#if defined(_WIN64)
+  value ^= value >> 32;
+#endif
+
+  return value;
+}
+#endif // _LIBCPP_ABI_MICROSOFT
+
+// FIXME: Remove the _LIBCPP_BUILDING_HAS_NO_ABI_LIBRARY configuration.
+#if (!defined(LIBCXX_BUILDING_LIBCXXABI) &&               \
+     !defined(LIBCXX_BUILDING_LIBCXXRT) &&                \
+     !defined(__GLIBCXX__) &&                             \
+     !defined(_LIBCPP_ABI_VCRUNTIME)) ||                  \
+    defined(_LIBCPP_BUILDING_HAS_NO_ABI_LIBRARY)
+std::type_info::~type_info()
+{
+}
+#endif
diff --git a/contrib/libs/cxxsupp/libcxx/src/utility.cpp b/contrib/libs/cxxsupp/libcxx/src/utility.cpp
new file mode 100644
index 00000000000..6a690dc2879
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/utility.cpp
@@ -0,0 +1,15 @@
+//===------------------------ utility.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "utility"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+const piecewise_construct_t piecewise_construct{};
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/valarray.cpp b/contrib/libs/cxxsupp/libcxx/src/valarray.cpp
new file mode 100644
index 00000000000..64d26583c74
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/valarray.cpp
@@ -0,0 +1,57 @@
+//===------------------------ valarray.cpp --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "valarray"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// These two symbols are part of the v1 ABI but not part of the >=v2 ABI.
+#if _LIBCPP_ABI_VERSION == 1
+template _LIBCPP_FUNC_VIS valarray<size_t>::valarray(size_t);
+template _LIBCPP_FUNC_VIS valarray<size_t>::~valarray();
+#endif
+
+template void valarray<size_t>::resize(size_t, size_t);
+
+void
+gslice::__init(size_t __start)
+{
+    valarray<size_t> __indices(__size_.size());
+    size_t __k = __size_.size() != 0;
+    for (size_t __i = 0; __i < __size_.size(); ++__i)
+        __k *= __size_[__i];
+    __1d_.resize(__k);
+    if (__1d_.size())
+    {
+        __k = 0;
+        __1d_[__k] = __start;
+        while (true)
+        {
+            size_t __i = __indices.size() - 1;
+            while (true)
+            {
+                if (++__indices[__i] < __size_[__i])
+                {
+                    ++__k;
+                    __1d_[__k] = __1d_[__k-1] + __stride_[__i];
+                    for (size_t __j = __i + 1; __j != __indices.size(); ++__j)
+                        __1d_[__k] -= __stride_[__j] * (__size_[__j] - 1);
+                    break;
+                }
+                else
+                {
+                    if (__i == 0)
+                        return;
+                    __indices[__i--] = 0;
+                }
+            }
+        }
+    }
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/src/variant.cpp b/contrib/libs/cxxsupp/libcxx/src/variant.cpp
new file mode 100644
index 00000000000..1fe70a1809c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/variant.cpp
@@ -0,0 +1,17 @@
+//===------------------------ variant.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "variant"
+
+namespace std {
+
+const char* bad_variant_access::what() const noexcept {
+  return "bad_variant_access";
+}
+
+}  // namespace std
diff --git a/contrib/libs/cxxsupp/libcxx/src/vector.cpp b/contrib/libs/cxxsupp/libcxx/src/vector.cpp
new file mode 100644
index 00000000000..0570ede733c
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/src/vector.cpp
@@ -0,0 +1,21 @@
+//===------------------------- vector.cpp ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "vector"
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+void __vector_base_common<true>::__throw_length_error() const {
+    _VSTD::__throw_length_error("vector");
+}
+
+void __vector_base_common<true>::__throw_out_of_range() const {
+    _VSTD::__throw_out_of_range("vector");
+}
+
+_LIBCPP_END_NAMESPACE_STD
diff --git a/contrib/libs/cxxsupp/libcxx/ya.make b/contrib/libs/cxxsupp/libcxx/ya.make
new file mode 100644
index 00000000000..15403fe6d5f
--- /dev/null
+++ b/contrib/libs/cxxsupp/libcxx/ya.make
@@ -0,0 +1,239 @@
+LIBRARY()
+
+LICENSE(
+    Apache-2.0 AND
+    Apache-2.0 WITH LLVM-exception AND
+    BSD-2-Clause AND
+    MIT AND
+    NCSA
+)
+
+LICENSE_TEXTS(.yandex_meta/licenses.list.txt)
+
+VERSION(2021-04-02-7959d59028dd126416cdf10dbbd22162922e1336)
+
+OWNER(
+    halyavin
+    somov
+    g:cpp-committee
+    g:cpp-contrib
+)
+
+ADDINCL(
+    GLOBAL contrib/libs/cxxsupp/libcxx/include
+)
+
+CXXFLAGS(-D_LIBCPP_BUILDING_LIBRARY)
+
+IF (OS_ANDROID)
+    DEFAULT(CXX_RT "default")
+    IF (ARCH_I686 OR ARCH_ARM7)
+        # 32-bit architectures require additional libandroid_support.so to be linked
+        # We add --start-group / --end-group statements due to the issue in NDK < r22.
+        # See: https://github.com/android/ndk/issues/1130
+        #
+        # Though these statements are not respected by LLD, they might have sense for other linkers.
+        LDFLAGS(
+            -Wl,--start-group
+            -lc++abi
+            -landroid_support
+            -Wl,--end-group
+        )
+    ELSE()
+        LDFLAGS(-lc++abi)
+    ENDIF()
+    CFLAGS(
+        -DLIBCXX_BUILDING_LIBCXXABI
+    )
+ELSEIF (OS_IOS)
+    # Take cxxabi implementation from system.
+    LDFLAGS(-lc++abi)
+    CFLAGS(
+        -DLIBCXX_BUILDING_LIBCXXABI
+    )
+    # Yet take builtins library from Arcadia
+    PEERDIR(
+        contrib/libs/cxxsupp/builtins
+    )
+ELSEIF (CLANG OR MUSL OR OS_DARWIN OR USE_LTO)
+    IF (ARCH_ARM7)
+        # XXX: libcxxrt support for ARM is currently broken
+        DEFAULT(CXX_RT "glibcxx_static")
+        # ARM7 OS_SDK has old libstdc++ without aligned allocation support
+        CFLAGS(
+            GLOBAL -fno-aligned-new
+        )
+    ELSE()
+        DEFAULT(CXX_RT "libcxxrt")
+    ENDIF()
+    IF (MUSL)
+        PEERDIR(
+            contrib/libs/musl/include
+        )
+    ENDIF()
+ELSEIF (OS_WINDOWS)
+    SRCS(
+        src/support/win32/locale_win32.cpp
+        src/support/win32/support.cpp
+        src/support/win32/atomic_win32.cpp
+        src/support/win32/new_win32.cpp
+        src/support/win32/thread_win32.cpp
+    )
+    CFLAGS(
+        GLOBAL -D_LIBCPP_VASPRINTF_DEFINED
+        GLOBAL -D_WCHAR_H_CPLUSPLUS_98_CONFORMANCE_
+    )
+    IF (CLANG_CL)
+        PEERDIR(
+            contrib/libs/cxxsupp/builtins
+        )
+    ENDIF()
+ELSE()
+    DEFAULT(CXX_RT "glibcxx_static")
+    CXXFLAGS(
+        -Wno-unknown-pragmas
+        -nostdinc++
+    )
+ENDIF()
+
+IF (OS_LINUX)
+    EXTRALIBS(-lpthread)
+ENDIF()
+
+IF (CLANG)
+    CFLAGS(
+        GLOBAL -nostdinc++
+    )
+ENDIF()
+
+# The CXX_RT variable controls which C++ runtime is used.
+# * libcxxrt        - https://github.com/pathscale/libcxxrt library stored in Arcadia
+# * glibcxx         - GNU C++ Library runtime with default (static) linkage
+# * glibcxx_static  - GNU C++ Library runtime with static linkage
+# * glibcxx_dynamic - GNU C++ Library runtime with dynamic linkage
+# * glibcxx_driver  - GNU C++ Library runtime provided by the compiler driver
+# * default         - default C++ runtime provided by the compiler driver
+#
+# All glibcxx* runtimes are taken from system/compiler SDK
+
+DEFAULT(CXX_RT "default")
+
+DISABLE(NEED_GLIBCXX_CXX17_SHIMS)
+
+IF (CXX_RT == "libcxxrt")
+    PEERDIR(
+        contrib/libs/cxxsupp/libcxxabi-parts
+        contrib/libs/cxxsupp/libcxxrt
+        contrib/libs/cxxsupp/builtins
+    )
+    ADDINCL(
+        contrib/libs/cxxsupp/libcxxrt
+    )
+    CFLAGS(
+        GLOBAL -DLIBCXX_BUILDING_LIBCXXRT
+    )
+    # These builtins are equivalent to clang -rtlib=compiler_rt and
+    # are needed by potentially any code generated by clang.
+    # With glibcxx runtime, builtins are provided by libgcc
+ELSEIF (CXX_RT == "glibcxx" OR CXX_RT == "glibcxx_static")
+    LDFLAGS(
+        -Wl,-Bstatic
+        -lsupc++
+        -lgcc
+        -lgcc_eh
+        -Wl,-Bdynamic
+    )
+    CXXFLAGS(-D__GLIBCXX__=1)
+    ENABLE(NEED_GLIBCXX_CXX17_SHIMS)
+    CFLAGS(
+        GLOBAL -DLIBCXX_BUILDING_LIBGCC
+    )
+ELSEIF (CXX_RT == "glibcxx_dynamic")
+    LDFLAGS(
+        -lgcc_s
+        -lstdc++
+    )
+    CXXFLAGS(-D__GLIBCXX__=1)
+    CFLAGS(
+        GLOBAL -DLIBCXX_BUILDING_LIBGCC
+    )
+    ENABLE(NEED_GLIBCXX_CXX17_SHIMS)
+ELSEIF (CXX_RT == "glibcxx_driver")
+    CXXFLAGS(-D__GLIBCXX__=1)
+ELSEIF (CXX_RT == "default")
+    # Do nothing
+ELSE()
+    MESSAGE(FATAL_ERROR "Unexpected CXX_RT value: ${CXX_RT}")
+ENDIF()
+
+IF (NEED_GLIBCXX_CXX17_SHIMS)
+    IF (GCC)
+        # Assume GCC is bundled with a modern enough version of C++ runtime
+    ELSEIF (OS_SDK == "ubuntu-12" OR OS_SDK == "ubuntu-14" OR OS_SDK == "ubuntu-16")
+        # Prior to ubuntu-18, system C++ runtime for C++17 is incomplete
+        SRCS(
+            glibcxx_eh_cxx17.cpp
+        )
+    ENDIF()
+ENDIF()
+
+NO_UTIL()
+
+NO_RUNTIME()
+
+NO_COMPILER_WARNINGS()
+
+IF (FUZZING)
+    NO_SANITIZE()
+    NO_SANITIZE_COVERAGE()
+ENDIF()
+
+SRCS(
+    src/algorithm.cpp
+    src/any.cpp
+    src/atomic.cpp
+    src/barrier.cpp
+    src/bind.cpp
+    src/charconv.cpp
+    src/chrono.cpp
+    src/condition_variable.cpp
+    src/condition_variable_destructor.cpp
+    src/debug.cpp
+    src/exception.cpp
+    src/filesystem/directory_iterator.cpp
+    src/filesystem/operations.cpp
+    src/format.cpp
+    src/functional.cpp
+    src/future.cpp
+    src/hash.cpp
+    src/ios.cpp
+    src/ios.instantiations.cpp
+    src/iostream.cpp
+    src/locale.cpp
+    src/memory.cpp
+    src/mutex.cpp
+    src/mutex_destructor.cpp
+    src/optional.cpp
+    src/random.cpp
+    src/random_shuffle.cpp
+    src/regex.cpp
+    src/shared_mutex.cpp
+    src/stdexcept.cpp
+    src/string.cpp
+    src/strstream.cpp
+    src/system_error.cpp
+    src/thread.cpp
+    src/typeinfo.cpp
+    src/utility.cpp
+    src/valarray.cpp
+    src/variant.cpp
+    src/vector.cpp
+)
+
+IF (NOT OS_WINDOWS)
+    SRCS(
+        src/new.cpp
+    )
+ENDIF()
+
+END()