Restoring authorship annotation for Andrey Khalyavin <halyavin@gmail.com>. Commit 1 of 2.

1 files changed, 1092 insertions, 1092 deletions

diff --git a/contrib/libs/cxxsupp/libcxx/include/__string b/contrib/libs/cxxsupp/libcxx/include/__string
index 7074a73538..dc9e86338f 100644
--- a/contrib/libs/cxxsupp/libcxx/include/__string
+++ b/contrib/libs/cxxsupp/libcxx/include/__string
@@ -1,353 +1,353 @@
-// -*- C++ -*-
-//===-------------------------- __string ----------------------------------===//
-//
+// -*- 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
+// 
+//===----------------------------------------------------------------------===// 
+ 
+#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;
@@ -355,234 +355,234 @@ struct _LIBCPP_TEMPLATE_VIS char_traits<char>
                 ++__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;
+#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;
+    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
-{
+    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;
+    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
+#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>
@@ -605,36 +605,36 @@ struct _LIBCPP_TEMPLATE_VIS char_traits<char8_t>
 
     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 _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;}
@@ -688,500 +688,500 @@ char_traits<char8_t>::find(const char_type* __s, size_t __n, const char_type& __
             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;
+    return nullptr; 
 }
 
-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
+#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