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

1 files changed, 950 insertions, 950 deletions

diff --git a/contrib/libs/cxxsupp/libcxx/include/string_view b/contrib/libs/cxxsupp/libcxx/include/string_view
index 34dbf0b28a..8df3ff297c 100644
--- a/contrib/libs/cxxsupp/libcxx/include/string_view
+++ b/contrib/libs/cxxsupp/libcxx/include/string_view
@@ -1,966 +1,966 @@
-// -*- C++ -*- 
-//===------------------------ string_view ---------------------------------===// 
-// 
+// -*- C++ -*-
+//===------------------------ string_view ---------------------------------===//
+//
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-// 
-//===----------------------------------------------------------------------===// 
- 
-#ifndef _LIBCPP_STRING_VIEW 
-#define _LIBCPP_STRING_VIEW 
- 
-/* 
-string_view synopsis 
- 
-namespace std { 
- 
-    // 7.2, Class template basic_string_view 
-    template<class charT, class traits = char_traits<charT>> 
-        class basic_string_view; 
- 
-    template<class charT, class traits> 
-    inline constexpr bool ranges::enable_view<basic_string_view<charT, traits>> = true; 
- 
-    template<class charT, class traits> 
-    inline constexpr bool ranges::enable_borrowed_range<basic_string_view<charT, traits>> = true;  // C++20 
- 
-    // 7.9, basic_string_view non-member comparison functions 
-    template<class charT, class traits> 
-    constexpr bool operator==(basic_string_view<charT, traits> x, 
-                              basic_string_view<charT, traits> y) noexcept; 
-    template<class charT, class traits> 
-    constexpr bool operator!=(basic_string_view<charT, traits> x, 
-                              basic_string_view<charT, traits> y) noexcept; 
-    template<class charT, class traits> 
-    constexpr bool operator< (basic_string_view<charT, traits> x, 
-                                 basic_string_view<charT, traits> y) noexcept; 
-    template<class charT, class traits> 
-    constexpr bool operator> (basic_string_view<charT, traits> x, 
-                              basic_string_view<charT, traits> y) noexcept; 
-    template<class charT, class traits> 
-    constexpr bool operator<=(basic_string_view<charT, traits> x, 
-                                 basic_string_view<charT, traits> y) noexcept; 
-    template<class charT, class traits> 
-    constexpr bool operator>=(basic_string_view<charT, traits> x, 
-                              basic_string_view<charT, traits> y) noexcept; 
-    // see below, sufficient additional overloads of comparison functions 
- 
-    // 7.10, Inserters and extractors 
-    template<class charT, class traits> 
-      basic_ostream<charT, traits>& 
-        operator<<(basic_ostream<charT, traits>& os, 
-                   basic_string_view<charT, traits> str); 
- 
-    // basic_string_view typedef names 
-    typedef basic_string_view<char> string_view; 
-    typedef basic_string_view<char8_t> u8string_view; // C++20 
-    typedef basic_string_view<char16_t> u16string_view; 
-    typedef basic_string_view<char32_t> u32string_view; 
-    typedef basic_string_view<wchar_t> wstring_view; 
- 
-    template<class charT, class traits = char_traits<charT>> 
-    class basic_string_view { 
-      public: 
-      // types 
-      typedef traits traits_type; 
-      typedef charT value_type; 
-      typedef charT* pointer; 
-      typedef const charT* const_pointer; 
-      typedef charT& reference; 
-      typedef const charT& const_reference; 
-      typedef implementation-defined const_iterator; 
-      typedef const_iterator iterator; 
-      typedef reverse_iterator<const_iterator> const_reverse_iterator; 
-      typedef const_reverse_iterator reverse_iterator; 
-      typedef size_t size_type; 
-      typedef ptrdiff_t difference_type; 
-      static constexpr size_type npos = size_type(-1); 
- 
-      // 7.3, basic_string_view constructors and assignment operators 
-      constexpr basic_string_view() noexcept; 
-      constexpr basic_string_view(const basic_string_view&) noexcept = default; 
-      basic_string_view& operator=(const basic_string_view&) noexcept = default; 
-      template<class Allocator> 
-      constexpr basic_string_view(const charT* str); 
-      basic_string_view(nullptr_t) = delete; // C++2b 
-      constexpr basic_string_view(const charT* str, size_type len); 
-      template <class It, class End> 
-      constexpr basic_string_view(It begin, End end); // C++20 
- 
-      // 7.4, basic_string_view iterator support 
-      constexpr const_iterator begin() const noexcept; 
-      constexpr const_iterator end() const noexcept; 
-      constexpr const_iterator cbegin() const noexcept; 
-      constexpr const_iterator cend() const noexcept; 
-      const_reverse_iterator rbegin() const noexcept; 
-      const_reverse_iterator rend() const noexcept; 
-      const_reverse_iterator crbegin() const noexcept; 
-      const_reverse_iterator crend() const noexcept; 
- 
-      // 7.5, basic_string_view capacity 
-      constexpr size_type size() const noexcept; 
-      constexpr size_type length() const noexcept; 
-      constexpr size_type max_size() const noexcept; 
-      constexpr bool empty() const noexcept; 
- 
-      // 7.6, basic_string_view element access 
-      constexpr const_reference operator[](size_type pos) const; 
-      constexpr const_reference at(size_type pos) const; 
-      constexpr const_reference front() const; 
-      constexpr const_reference back() const; 
-      constexpr const_pointer data() const noexcept; 
- 
-      // 7.7, basic_string_view modifiers 
-      constexpr void remove_prefix(size_type n); 
-      constexpr void remove_suffix(size_type n); 
-      constexpr void swap(basic_string_view& s) noexcept; 
- 
-      size_type copy(charT* s, size_type n, size_type pos = 0) const;  // constexpr in C++20 
- 
-      constexpr basic_string_view substr(size_type pos = 0, size_type n = npos) const; 
-      constexpr int compare(basic_string_view s) const noexcept; 
-      constexpr int compare(size_type pos1, size_type n1, basic_string_view s) const; 
-      constexpr int compare(size_type pos1, size_type n1, 
-                            basic_string_view s, size_type pos2, size_type n2) const; 
-      constexpr int compare(const charT* s) const; 
-      constexpr int compare(size_type pos1, size_type n1, const charT* s) const; 
-      constexpr int compare(size_type pos1, size_type n1, 
-                            const charT* s, size_type n2) const; 
-      constexpr size_type find(basic_string_view s, size_type pos = 0) const noexcept; 
-      constexpr size_type find(charT c, size_type pos = 0) const noexcept; 
-      constexpr size_type find(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension 
-      constexpr size_type find(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension 
-      constexpr size_type rfind(basic_string_view s, size_type pos = npos) const noexcept; 
-      constexpr size_type rfind(charT c, size_type pos = npos) const noexcept; 
-      constexpr size_type rfind(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension 
-      constexpr size_type rfind(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension 
-      constexpr size_type find_first_of(basic_string_view s, size_type pos = 0) const noexcept; 
-      constexpr size_type find_first_of(charT c, size_type pos = 0) const noexcept; 
-      constexpr size_type find_first_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension 
-      constexpr size_type find_first_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension 
-      constexpr size_type find_last_of(basic_string_view s, size_type pos = npos) const noexcept; 
-      constexpr size_type find_last_of(charT c, size_type pos = npos) const noexcept; 
-      constexpr size_type find_last_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension 
-      constexpr size_type find_last_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension 
-      constexpr size_type find_first_not_of(basic_string_view s, size_type pos = 0) const noexcept; 
-      constexpr size_type find_first_not_of(charT c, size_type pos = 0) const noexcept; 
-      constexpr size_type find_first_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension 
-      constexpr size_type find_first_not_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension 
-      constexpr size_type find_last_not_of(basic_string_view s, size_type pos = npos) const noexcept; 
-      constexpr size_type find_last_not_of(charT c, size_type pos = npos) const noexcept; 
-      constexpr size_type find_last_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension 
-      constexpr size_type find_last_not_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension 
- 
-      constexpr bool starts_with(basic_string_view s) const noexcept; // C++20 
-      constexpr bool starts_with(charT c) const noexcept;             // C++20 
-      constexpr bool starts_with(const charT* s) const;               // C++20 
-      constexpr bool ends_with(basic_string_view s) const noexcept;   // C++20 
-      constexpr bool ends_with(charT c) const noexcept;               // C++20 
-      constexpr bool ends_with(const charT* s) const;                 // C++20 
- 
-      constexpr bool contains(basic_string_view s) const noexcept; // C++2b 
-      constexpr bool contains(charT c) const noexcept;             // C++2b 
-      constexpr bool contains(const charT* s) const;               // C++2b 
- 
-     private: 
-      const_pointer data_;  // exposition only 
-      size_type     size_;  // exposition only 
-    }; 
- 
-  // basic_string_view deduction guides 
-  template<class It, class End> 
-    basic_string_view(It, End) -> basic_string_view<iter_value_t<It>>; // C++20 
- 
-  // 7.11, Hash support 
-  template <class T> struct hash; 
-  template <> struct hash<string_view>; 
-  template <> struct hash<u8string_view>; // C++20 
-  template <> struct hash<u16string_view>; 
-  template <> struct hash<u32string_view>; 
-  template <> struct hash<wstring_view>; 
- 
-  constexpr basic_string_view<char>     operator "" sv( const char *str,     size_t len ) noexcept; 
-  constexpr basic_string_view<wchar_t>  operator "" sv( const wchar_t *str,  size_t len ) noexcept; 
-  constexpr basic_string_view<char8_t>  operator "" sv( const char8_t *str,  size_t len ) noexcept; // C++20 
-  constexpr basic_string_view<char16_t> operator "" sv( const char16_t *str, size_t len ) noexcept; 
-  constexpr basic_string_view<char32_t> operator "" sv( const char32_t *str, size_t len ) noexcept; 
- 
-}  // namespace std 
- 
- 
-*/ 
- 
-#include <__concepts/convertible_to.h> 
-#include <__concepts/same_as.h> 
-#include <__config> 
-#include <__debug> 
-#include <__ranges/enable_borrowed_range.h> 
-#include <__ranges/enable_view.h> 
-#include <__string> 
-#include <algorithm> 
-#include <compare> 
-#include <iosfwd> 
-#include <iterator> 
-#include <limits> 
-#include <stdexcept> 
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_STRING_VIEW
+#define _LIBCPP_STRING_VIEW
+
+/*
+string_view synopsis
+
+namespace std {
+
+    // 7.2, Class template basic_string_view
+    template<class charT, class traits = char_traits<charT>>
+        class basic_string_view;
+
+    template<class charT, class traits>
+    inline constexpr bool ranges::enable_view<basic_string_view<charT, traits>> = true;
+
+    template<class charT, class traits>
+    inline constexpr bool ranges::enable_borrowed_range<basic_string_view<charT, traits>> = true;  // C++20
+
+    // 7.9, basic_string_view non-member comparison functions
+    template<class charT, class traits>
+    constexpr bool operator==(basic_string_view<charT, traits> x,
+                              basic_string_view<charT, traits> y) noexcept;
+    template<class charT, class traits>
+    constexpr bool operator!=(basic_string_view<charT, traits> x,
+                              basic_string_view<charT, traits> y) noexcept;
+    template<class charT, class traits>
+    constexpr bool operator< (basic_string_view<charT, traits> x,
+                                 basic_string_view<charT, traits> y) noexcept;
+    template<class charT, class traits>
+    constexpr bool operator> (basic_string_view<charT, traits> x,
+                              basic_string_view<charT, traits> y) noexcept;
+    template<class charT, class traits>
+    constexpr bool operator<=(basic_string_view<charT, traits> x,
+                                 basic_string_view<charT, traits> y) noexcept;
+    template<class charT, class traits>
+    constexpr bool operator>=(basic_string_view<charT, traits> x,
+                              basic_string_view<charT, traits> y) noexcept;
+    // see below, sufficient additional overloads of comparison functions
+
+    // 7.10, Inserters and extractors
+    template<class charT, class traits>
+      basic_ostream<charT, traits>&
+        operator<<(basic_ostream<charT, traits>& os,
+                   basic_string_view<charT, traits> str);
+
+    // basic_string_view typedef names
+    typedef basic_string_view<char> string_view;
+    typedef basic_string_view<char8_t> u8string_view; // C++20
+    typedef basic_string_view<char16_t> u16string_view;
+    typedef basic_string_view<char32_t> u32string_view;
+    typedef basic_string_view<wchar_t> wstring_view;
+
+    template<class charT, class traits = char_traits<charT>>
+    class basic_string_view {
+      public:
+      // types
+      typedef traits traits_type;
+      typedef charT value_type;
+      typedef charT* pointer;
+      typedef const charT* const_pointer;
+      typedef charT& reference;
+      typedef const charT& const_reference;
+      typedef implementation-defined const_iterator;
+      typedef const_iterator iterator;
+      typedef reverse_iterator<const_iterator> const_reverse_iterator;
+      typedef const_reverse_iterator reverse_iterator;
+      typedef size_t size_type;
+      typedef ptrdiff_t difference_type;
+      static constexpr size_type npos = size_type(-1);
+
+      // 7.3, basic_string_view constructors and assignment operators
+      constexpr basic_string_view() noexcept;
+      constexpr basic_string_view(const basic_string_view&) noexcept = default;
+      basic_string_view& operator=(const basic_string_view&) noexcept = default;
+      template<class Allocator>
+      constexpr basic_string_view(const charT* str);
+      basic_string_view(nullptr_t) = delete; // C++2b
+      constexpr basic_string_view(const charT* str, size_type len);
+      template <class It, class End>
+      constexpr basic_string_view(It begin, End end); // C++20
+
+      // 7.4, basic_string_view iterator support
+      constexpr const_iterator begin() const noexcept;
+      constexpr const_iterator end() const noexcept;
+      constexpr const_iterator cbegin() const noexcept;
+      constexpr const_iterator cend() const noexcept;
+      const_reverse_iterator rbegin() const noexcept;
+      const_reverse_iterator rend() const noexcept;
+      const_reverse_iterator crbegin() const noexcept;
+      const_reverse_iterator crend() const noexcept;
+
+      // 7.5, basic_string_view capacity
+      constexpr size_type size() const noexcept;
+      constexpr size_type length() const noexcept;
+      constexpr size_type max_size() const noexcept;
+      constexpr bool empty() const noexcept;
+
+      // 7.6, basic_string_view element access
+      constexpr const_reference operator[](size_type pos) const;
+      constexpr const_reference at(size_type pos) const;
+      constexpr const_reference front() const;
+      constexpr const_reference back() const;
+      constexpr const_pointer data() const noexcept;
+
+      // 7.7, basic_string_view modifiers
+      constexpr void remove_prefix(size_type n);
+      constexpr void remove_suffix(size_type n);
+      constexpr void swap(basic_string_view& s) noexcept;
+
+      size_type copy(charT* s, size_type n, size_type pos = 0) const;  // constexpr in C++20
+
+      constexpr basic_string_view substr(size_type pos = 0, size_type n = npos) const;
+      constexpr int compare(basic_string_view s) const noexcept;
+      constexpr int compare(size_type pos1, size_type n1, basic_string_view s) const;
+      constexpr int compare(size_type pos1, size_type n1,
+                            basic_string_view s, size_type pos2, size_type n2) const;
+      constexpr int compare(const charT* s) const;
+      constexpr int compare(size_type pos1, size_type n1, const charT* s) const;
+      constexpr int compare(size_type pos1, size_type n1,
+                            const charT* s, size_type n2) const;
+      constexpr size_type find(basic_string_view s, size_type pos = 0) const noexcept;
+      constexpr size_type find(charT c, size_type pos = 0) const noexcept;
+      constexpr size_type find(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
+      constexpr size_type find(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
+      constexpr size_type rfind(basic_string_view s, size_type pos = npos) const noexcept;
+      constexpr size_type rfind(charT c, size_type pos = npos) const noexcept;
+      constexpr size_type rfind(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
+      constexpr size_type rfind(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
+      constexpr size_type find_first_of(basic_string_view s, size_type pos = 0) const noexcept;
+      constexpr size_type find_first_of(charT c, size_type pos = 0) const noexcept;
+      constexpr size_type find_first_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
+      constexpr size_type find_first_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
+      constexpr size_type find_last_of(basic_string_view s, size_type pos = npos) const noexcept;
+      constexpr size_type find_last_of(charT c, size_type pos = npos) const noexcept;
+      constexpr size_type find_last_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
+      constexpr size_type find_last_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
+      constexpr size_type find_first_not_of(basic_string_view s, size_type pos = 0) const noexcept;
+      constexpr size_type find_first_not_of(charT c, size_type pos = 0) const noexcept;
+      constexpr size_type find_first_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
+      constexpr size_type find_first_not_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
+      constexpr size_type find_last_not_of(basic_string_view s, size_type pos = npos) const noexcept;
+      constexpr size_type find_last_not_of(charT c, size_type pos = npos) const noexcept;
+      constexpr size_type find_last_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
+      constexpr size_type find_last_not_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
+
+      constexpr bool starts_with(basic_string_view s) const noexcept; // C++20
+      constexpr bool starts_with(charT c) const noexcept;             // C++20
+      constexpr bool starts_with(const charT* s) const;               // C++20
+      constexpr bool ends_with(basic_string_view s) const noexcept;   // C++20
+      constexpr bool ends_with(charT c) const noexcept;               // C++20
+      constexpr bool ends_with(const charT* s) const;                 // C++20
+
+      constexpr bool contains(basic_string_view s) const noexcept; // C++2b
+      constexpr bool contains(charT c) const noexcept;             // C++2b
+      constexpr bool contains(const charT* s) const;               // C++2b
+
+     private:
+      const_pointer data_;  // exposition only
+      size_type     size_;  // exposition only
+    };
+
+  // basic_string_view deduction guides
+  template<class It, class End>
+    basic_string_view(It, End) -> basic_string_view<iter_value_t<It>>; // C++20
+
+  // 7.11, Hash support
+  template <class T> struct hash;
+  template <> struct hash<string_view>;
+  template <> struct hash<u8string_view>; // C++20
+  template <> struct hash<u16string_view>;
+  template <> struct hash<u32string_view>;
+  template <> struct hash<wstring_view>;
+
+  constexpr basic_string_view<char>     operator "" sv( const char *str,     size_t len ) noexcept;
+  constexpr basic_string_view<wchar_t>  operator "" sv( const wchar_t *str,  size_t len ) noexcept;
+  constexpr basic_string_view<char8_t>  operator "" sv( const char8_t *str,  size_t len ) noexcept; // C++20
+  constexpr basic_string_view<char16_t> operator "" sv( const char16_t *str, size_t len ) noexcept;
+  constexpr basic_string_view<char32_t> operator "" sv( const char32_t *str, size_t len ) noexcept;
+
+}  // namespace std
+
+
+*/
+
+#include <__concepts/convertible_to.h>
+#include <__concepts/same_as.h>
+#include <__config>
+#include <__debug>
+#include <__ranges/enable_borrowed_range.h>
+#include <__ranges/enable_view.h>
+#include <__string>
+#include <algorithm>
+#include <compare>
+#include <iosfwd>
+#include <iterator>
+#include <limits>
+#include <stdexcept>
 #include <version>
- 
-#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 
-#pragma GCC system_header 
-#endif 
- 
-#ifdef _LIBCPP_COMPILER_MSVC 
-#pragma warning ( push ) 
-#pragma warning ( disable : 4455 ) 
-#endif 
- 
-_LIBCPP_PUSH_MACROS 
-#include <__undef_macros> 
- 
- 
-_LIBCPP_BEGIN_NAMESPACE_STD 
- 
-template<class _CharT, class _Traits = char_traits<_CharT> > 
-    class _LIBCPP_TEMPLATE_VIS basic_string_view; 
- 
-typedef basic_string_view<char>     string_view; 
-#ifndef _LIBCPP_HAS_NO_CHAR8_T 
-typedef basic_string_view<char8_t>  u8string_view; 
-#endif 
-typedef basic_string_view<char16_t> u16string_view; 
-typedef basic_string_view<char32_t> u32string_view; 
-#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS 
-typedef basic_string_view<wchar_t>  wstring_view; 
-#endif 
- 
-template<class _CharT, class _Traits> 
-class 
-    _LIBCPP_PREFERRED_NAME(string_view) 
-#ifndef _LIBCPP_HAS_NO_CHAR8_T 
-    _LIBCPP_PREFERRED_NAME(u8string_view) 
-#endif 
-    _LIBCPP_PREFERRED_NAME(u16string_view) 
-    _LIBCPP_PREFERRED_NAME(u32string_view) 
-    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wstring_view)) 
-    basic_string_view { 
-public: 
-    // types 
-    typedef _Traits                                    traits_type; 
-    typedef _CharT                                     value_type; 
-    typedef _CharT*                                    pointer; 
-    typedef const _CharT*                              const_pointer; 
-    typedef _CharT&                                    reference; 
-    typedef const _CharT&                              const_reference; 
-    typedef const_pointer                              const_iterator; // See [string.view.iterators] 
-    typedef const_iterator                             iterator; 
-    typedef _VSTD::reverse_iterator<const_iterator>    const_reverse_iterator; 
-    typedef const_reverse_iterator                     reverse_iterator; 
-    typedef size_t                                     size_type; 
-    typedef ptrdiff_t                                  difference_type; 
-    static _LIBCPP_CONSTEXPR const size_type npos = -1; // size_type(-1); 
- 
-    static_assert((!is_array<value_type>::value), "Character type of basic_string_view must not be an array"); 
-    static_assert(( is_standard_layout<value_type>::value), "Character type of basic_string_view must be standard-layout"); 
-    static_assert(( is_trivial<value_type>::value), "Character type of basic_string_view must be trivial"); 
-    static_assert((is_same<_CharT, typename traits_type::char_type>::value), 
-                  "traits_type::char_type must be the same type as CharT"); 
- 
-    // [string.view.cons], construct/copy 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    basic_string_view() _NOEXCEPT : __data (nullptr), __size(0) {} 
- 
-    _LIBCPP_INLINE_VISIBILITY 
-    basic_string_view(const basic_string_view&) _NOEXCEPT = default; 
- 
-    _LIBCPP_INLINE_VISIBILITY 
-    basic_string_view& operator=(const basic_string_view&) _NOEXCEPT = default; 
- 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( push )
+#pragma warning ( disable : 4455 )
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _CharT, class _Traits = char_traits<_CharT> >
+    class _LIBCPP_TEMPLATE_VIS basic_string_view;
+
+typedef basic_string_view<char>     string_view;
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+typedef basic_string_view<char8_t>  u8string_view;
+#endif
+typedef basic_string_view<char16_t> u16string_view;
+typedef basic_string_view<char32_t> u32string_view;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+typedef basic_string_view<wchar_t>  wstring_view;
+#endif
+
+template<class _CharT, class _Traits>
+class
+    _LIBCPP_PREFERRED_NAME(string_view)
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+    _LIBCPP_PREFERRED_NAME(u8string_view)
+#endif
+    _LIBCPP_PREFERRED_NAME(u16string_view)
+    _LIBCPP_PREFERRED_NAME(u32string_view)
+    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wstring_view))
+    basic_string_view {
+public:
+    // types
+    typedef _Traits                                    traits_type;
+    typedef _CharT                                     value_type;
+    typedef _CharT*                                    pointer;
+    typedef const _CharT*                              const_pointer;
+    typedef _CharT&                                    reference;
+    typedef const _CharT&                              const_reference;
+    typedef const_pointer                              const_iterator; // See [string.view.iterators]
+    typedef const_iterator                             iterator;
+    typedef _VSTD::reverse_iterator<const_iterator>    const_reverse_iterator;
+    typedef const_reverse_iterator                     reverse_iterator;
+    typedef size_t                                     size_type;
+    typedef ptrdiff_t                                  difference_type;
+    static _LIBCPP_CONSTEXPR const size_type npos = -1; // size_type(-1);
+
+    static_assert((!is_array<value_type>::value), "Character type of basic_string_view must not be an array");
+    static_assert(( is_standard_layout<value_type>::value), "Character type of basic_string_view must be standard-layout");
+    static_assert(( is_trivial<value_type>::value), "Character type of basic_string_view must be trivial");
+    static_assert((is_same<_CharT, typename traits_type::char_type>::value),
+                  "traits_type::char_type must be the same type as CharT");
+
+    // [string.view.cons], construct/copy
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    basic_string_view() _NOEXCEPT : __data (nullptr), __size(0) {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string_view(const basic_string_view&) _NOEXCEPT = default;
+
+    _LIBCPP_INLINE_VISIBILITY
+    basic_string_view& operator=(const basic_string_view&) _NOEXCEPT = default;
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
     basic_string_view(nullptr_t, size_t) = delete;
 
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
-    basic_string_view(const _CharT* __s, size_type __len) _NOEXCEPT 
-        : __data(__s), __size(__len) 
-    { 
-#if _LIBCPP_STD_VER > 11 
-    _LIBCPP_ASSERT(__len == 0 || __s != nullptr, "string_view::string_view(_CharT *, size_t): received nullptr"); 
-#endif 
-    } 
- 
-#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES) 
-    template <contiguous_iterator _It, sized_sentinel_for<_It> _End> 
-      requires (same_as<iter_value_t<_It>, _CharT> && !convertible_to<_End, size_type>) 
-    constexpr _LIBCPP_HIDE_FROM_ABI basic_string_view(_It __begin, _End __end) 
-       : __data(_VSTD::to_address(__begin)), __size(__end - __begin) 
-    { 
-      _LIBCPP_ASSERT((__end - __begin) >= 0, "std::string_view::string_view(iterator, sentinel) received invalid range"); 
-    } 
-#endif 
- 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
+    basic_string_view(const _CharT* __s, size_type __len) _NOEXCEPT
+        : __data(__s), __size(__len)
+    {
+#if _LIBCPP_STD_VER > 11
+    _LIBCPP_ASSERT(__len == 0 || __s != nullptr, "string_view::string_view(_CharT *, size_t): received nullptr");
+#endif
+    }
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+    template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
+      requires (same_as<iter_value_t<_It>, _CharT> && !convertible_to<_End, size_type>)
+    constexpr _LIBCPP_HIDE_FROM_ABI basic_string_view(_It __begin, _End __end)
+       : __data(_VSTD::to_address(__begin)), __size(__end - __begin)
+    {
+      _LIBCPP_ASSERT((__end - __begin) >= 0, "std::string_view::string_view(iterator, sentinel) received invalid range");
+    }
+#endif
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    basic_string_view(nullptr_t) = delete;
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    basic_string_view(const _CharT* __s)
+        : __data(__s), __size(_VSTD::__char_traits_length_checked<_Traits>(__s)) {}
+
+#if _LIBCPP_STD_VER > 20
     basic_string_view(nullptr_t) = delete;
+#endif
+
+    // [string.view.iterators], iterators
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_iterator begin()  const _NOEXCEPT { return cbegin(); }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_iterator end()    const _NOEXCEPT { return cend(); }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_iterator cbegin() const _NOEXCEPT { return __data; }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_iterator cend()   const _NOEXCEPT { return __data + __size; }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rbegin()   const _NOEXCEPT { return const_reverse_iterator(cend()); }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator rend()     const _NOEXCEPT { return const_reverse_iterator(cbegin()); }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crbegin()  const _NOEXCEPT { return const_reverse_iterator(cend()); }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
+    const_reverse_iterator crend()    const _NOEXCEPT { return const_reverse_iterator(cbegin()); }
+
+    // [string.view.capacity], capacity
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    size_type size()     const _NOEXCEPT { return __size; }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    size_type length()   const _NOEXCEPT { return __size; }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    size_type max_size() const _NOEXCEPT { return numeric_limits<size_type>::max(); }
+
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    bool empty()         const _NOEXCEPT { return __size == 0; }
+
+    // [string.view.access], element access
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_reference operator[](size_type __pos) const _NOEXCEPT {
+      return _LIBCPP_ASSERT(__pos < size(), "string_view[] index out of bounds"), __data[__pos];
+    }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_reference at(size_type __pos) const
+    {
+        return __pos >= size()
+            ? (__throw_out_of_range("string_view::at"), __data[0])
+            : __data[__pos];
+    }
 
     _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
-    basic_string_view(const _CharT* __s) 
-        : __data(__s), __size(_VSTD::__char_traits_length_checked<_Traits>(__s)) {} 
- 
-#if _LIBCPP_STD_VER > 20 
-    basic_string_view(nullptr_t) = delete; 
-#endif 
- 
-    // [string.view.iterators], iterators 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    const_iterator begin()  const _NOEXCEPT { return cbegin(); } 
- 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    const_iterator end()    const _NOEXCEPT { return cend(); } 
- 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    const_iterator cbegin() const _NOEXCEPT { return __data; } 
- 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    const_iterator cend()   const _NOEXCEPT { return __data + __size; } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY 
-    const_reverse_iterator rbegin()   const _NOEXCEPT { return const_reverse_iterator(cend()); } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY 
-    const_reverse_iterator rend()     const _NOEXCEPT { return const_reverse_iterator(cbegin()); } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY 
-    const_reverse_iterator crbegin()  const _NOEXCEPT { return const_reverse_iterator(cend()); } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY 
-    const_reverse_iterator crend()    const _NOEXCEPT { return const_reverse_iterator(cbegin()); } 
- 
-    // [string.view.capacity], capacity 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    size_type size()     const _NOEXCEPT { return __size; } 
- 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    size_type length()   const _NOEXCEPT { return __size; } 
- 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    size_type max_size() const _NOEXCEPT { return numeric_limits<size_type>::max(); } 
- 
-    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR 
-    bool empty()         const _NOEXCEPT { return __size == 0; } 
- 
-    // [string.view.access], element access 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    const_reference operator[](size_type __pos) const _NOEXCEPT { 
-      return _LIBCPP_ASSERT(__pos < size(), "string_view[] index out of bounds"), __data[__pos]; 
-    } 
- 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    const_reference at(size_type __pos) const 
-    { 
-        return __pos >= size() 
-            ? (__throw_out_of_range("string_view::at"), __data[0]) 
-            : __data[__pos]; 
-    } 
- 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    const_reference front() const _NOEXCEPT 
-    { 
-        return _LIBCPP_ASSERT(!empty(), "string_view::front(): string is empty"), __data[0]; 
-    } 
- 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    const_reference back() const _NOEXCEPT 
-    { 
-        return _LIBCPP_ASSERT(!empty(), "string_view::back(): string is empty"), __data[__size-1]; 
-    } 
- 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    const_pointer data() const _NOEXCEPT { return __data; } 
- 
-    // [string.view.modifiers], modifiers: 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    void remove_prefix(size_type __n) _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__n <= size(), "remove_prefix() can't remove more than size()"); 
-        __data += __n; 
-        __size -= __n; 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    void remove_suffix(size_type __n) _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__n <= size(), "remove_suffix() can't remove more than size()"); 
-        __size -= __n; 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    void swap(basic_string_view& __other) _NOEXCEPT 
-    { 
-        const value_type *__p = __data; 
-        __data = __other.__data; 
-        __other.__data = __p; 
- 
-        size_type __sz = __size; 
-        __size = __other.__size; 
-        __other.__size = __sz; 
-    } 
- 
-    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 
-    size_type copy(_CharT* __s, size_type __n, size_type __pos = 0) const 
-    { 
-        if (__pos > size()) 
-            __throw_out_of_range("string_view::copy"); 
+    const_reference front() const _NOEXCEPT
+    {
+        return _LIBCPP_ASSERT(!empty(), "string_view::front(): string is empty"), __data[0];
+    }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_reference back() const _NOEXCEPT
+    {
+        return _LIBCPP_ASSERT(!empty(), "string_view::back(): string is empty"), __data[__size-1];
+    }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    const_pointer data() const _NOEXCEPT { return __data; }
+
+    // [string.view.modifiers], modifiers:
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    void remove_prefix(size_type __n) _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n <= size(), "remove_prefix() can't remove more than size()");
+        __data += __n;
+        __size -= __n;
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    void remove_suffix(size_type __n) _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n <= size(), "remove_suffix() can't remove more than size()");
+        __size -= __n;
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    void swap(basic_string_view& __other) _NOEXCEPT
+    {
+        const value_type *__p = __data;
+        __data = __other.__data;
+        __other.__data = __p;
+
+        size_type __sz = __size;
+        __size = __other.__size;
+        __other.__size = __sz;
+    }
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
+    size_type copy(_CharT* __s, size_type __n, size_type __pos = 0) const
+    {
+        if (__pos > size())
+            __throw_out_of_range("string_view::copy");
         size_type __rlen = _VSTD::min(__n, size() - __pos);
-        _Traits::copy(__s, data() + __pos, __rlen); 
-        return __rlen; 
-    } 
- 
-    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY 
-    basic_string_view substr(size_type __pos = 0, size_type __n = npos) const 
-    { 
-        return __pos > size() 
-            ? (__throw_out_of_range("string_view::substr"), basic_string_view()) 
-            : basic_string_view(data() + __pos, _VSTD::min(__n, size() - __pos)); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 int compare(basic_string_view __sv) const _NOEXCEPT 
-    { 
-        size_type __rlen = _VSTD::min( size(), __sv.size()); 
-        int __retval = _Traits::compare(data(), __sv.data(), __rlen); 
-        if ( __retval == 0 ) // first __rlen chars matched 
-            __retval = size() == __sv.size() ? 0 : ( size() < __sv.size() ? -1 : 1 ); 
-        return __retval; 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    int compare(size_type __pos1, size_type __n1, basic_string_view __sv) const 
-    { 
-        return substr(__pos1, __n1).compare(__sv); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    int compare(                       size_type __pos1, size_type __n1, 
-                basic_string_view __sv, size_type __pos2, size_type __n2) const 
-    { 
-        return substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2)); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    int compare(const _CharT* __s) const _NOEXCEPT 
-    { 
-        return compare(basic_string_view(__s)); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    int compare(size_type __pos1, size_type __n1, const _CharT* __s) const 
-    { 
-        return substr(__pos1, __n1).compare(basic_string_view(__s)); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    int compare(size_type __pos1, size_type __n1, const _CharT* __s, size_type __n2) const 
-    { 
-        return substr(__pos1, __n1).compare(basic_string_view(__s, __n2)); 
-    } 
- 
-    // find 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr"); 
-        return __str_find<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s.data(), __pos, __s.size()); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find(_CharT __c, size_type __pos = 0) const _NOEXCEPT 
-    { 
-        return __str_find<value_type, size_type, traits_type, npos> 
-            (data(), size(), __c, __pos); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find(): received nullptr"); 
-        return __str_find<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s, __pos, __n); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__s != nullptr, "string_view::find(): received nullptr"); 
-        return __str_find<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s, __pos, traits_type::length(__s)); 
-    } 
- 
-    // rfind 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type rfind(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr"); 
-        return __str_rfind<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s.data(), __pos, __s.size()); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type rfind(_CharT __c, size_type __pos = npos) const _NOEXCEPT 
-    { 
-        return __str_rfind<value_type, size_type, traits_type, npos> 
-            (data(), size(), __c, __pos); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type rfind(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::rfind(): received nullptr"); 
-        return __str_rfind<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s, __pos, __n); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type rfind(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__s != nullptr, "string_view::rfind(): received nullptr"); 
-        return __str_rfind<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s, __pos, traits_type::length(__s)); 
-    } 
- 
-    // find_first_of 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_first_of(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_first_of(): received nullptr"); 
-        return __str_find_first_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s.data(), __pos, __s.size()); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_first_of(_CharT __c, size_type __pos = 0) const _NOEXCEPT 
-    { return find(__c, __pos); } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_first_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_first_of(): received nullptr"); 
-        return __str_find_first_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s, __pos, __n); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_first_of(const _CharT* __s, size_type __pos=0) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_first_of(): received nullptr"); 
-        return __str_find_first_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s, __pos, traits_type::length(__s)); 
-    } 
- 
-    // find_last_of 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_last_of(basic_string_view __s, size_type __pos=npos) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_last_of(): received nullptr"); 
-        return __str_find_last_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s.data(), __pos, __s.size()); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_last_of(_CharT __c, size_type __pos = npos) const _NOEXCEPT 
-    { return rfind(__c, __pos); } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_last_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_last_of(): received nullptr"); 
-        return __str_find_last_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s, __pos, __n); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_last_of(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_last_of(): received nullptr"); 
-        return __str_find_last_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s, __pos, traits_type::length(__s)); 
-    } 
- 
-    // find_first_not_of 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_first_not_of(basic_string_view __s, size_type __pos=0) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_first_not_of(): received nullptr"); 
-        return __str_find_first_not_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s.data(), __pos, __s.size()); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_first_not_of(_CharT __c, size_type __pos=0) const _NOEXCEPT 
-    { 
-        return __str_find_first_not_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __c, __pos); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_first_not_of(): received nullptr"); 
-        return __str_find_first_not_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s, __pos, __n); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_first_not_of(const _CharT* __s, size_type __pos=0) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_first_not_of(): received nullptr"); 
-        return __str_find_first_not_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s, __pos, traits_type::length(__s)); 
-    } 
- 
-    // find_last_not_of 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_last_not_of(basic_string_view __s, size_type __pos=npos) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_last_not_of(): received nullptr"); 
-        return __str_find_last_not_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s.data(), __pos, __s.size()); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_last_not_of(_CharT __c, size_type __pos=npos) const _NOEXCEPT 
-    { 
-        return __str_find_last_not_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __c, __pos); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_last_not_of(): received nullptr"); 
-        return __str_find_last_not_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s, __pos, __n); 
-    } 
- 
-    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-    size_type find_last_not_of(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT 
-    { 
-        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_last_not_of(): received nullptr"); 
-        return __str_find_last_not_of<value_type, size_type, traits_type, npos> 
-            (data(), size(), __s, __pos, traits_type::length(__s)); 
-    } 
- 
+        _Traits::copy(__s, data() + __pos, __rlen);
+        return __rlen;
+    }
+
+    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
+    basic_string_view substr(size_type __pos = 0, size_type __n = npos) const
+    {
+        return __pos > size()
+            ? (__throw_out_of_range("string_view::substr"), basic_string_view())
+            : basic_string_view(data() + __pos, _VSTD::min(__n, size() - __pos));
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 int compare(basic_string_view __sv) const _NOEXCEPT
+    {
+        size_type __rlen = _VSTD::min( size(), __sv.size());
+        int __retval = _Traits::compare(data(), __sv.data(), __rlen);
+        if ( __retval == 0 ) // first __rlen chars matched
+            __retval = size() == __sv.size() ? 0 : ( size() < __sv.size() ? -1 : 1 );
+        return __retval;
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    int compare(size_type __pos1, size_type __n1, basic_string_view __sv) const
+    {
+        return substr(__pos1, __n1).compare(__sv);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    int compare(                       size_type __pos1, size_type __n1,
+                basic_string_view __sv, size_type __pos2, size_type __n2) const
+    {
+        return substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    int compare(const _CharT* __s) const _NOEXCEPT
+    {
+        return compare(basic_string_view(__s));
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    int compare(size_type __pos1, size_type __n1, const _CharT* __s) const
+    {
+        return substr(__pos1, __n1).compare(basic_string_view(__s));
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    int compare(size_type __pos1, size_type __n1, const _CharT* __s, size_type __n2) const
+    {
+        return substr(__pos1, __n1).compare(basic_string_view(__s, __n2));
+    }
+
+    // find
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
+        return __str_find<value_type, size_type, traits_type, npos>
+            (data(), size(), __s.data(), __pos, __s.size());
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find(_CharT __c, size_type __pos = 0) const _NOEXCEPT
+    {
+        return __str_find<value_type, size_type, traits_type, npos>
+            (data(), size(), __c, __pos);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find(): received nullptr");
+        return __str_find<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, __n);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s != nullptr, "string_view::find(): received nullptr");
+        return __str_find<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, traits_type::length(__s));
+    }
+
+    // rfind
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type rfind(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
+        return __str_rfind<value_type, size_type, traits_type, npos>
+            (data(), size(), __s.data(), __pos, __s.size());
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type rfind(_CharT __c, size_type __pos = npos) const _NOEXCEPT
+    {
+        return __str_rfind<value_type, size_type, traits_type, npos>
+            (data(), size(), __c, __pos);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type rfind(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::rfind(): received nullptr");
+        return __str_rfind<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, __n);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type rfind(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s != nullptr, "string_view::rfind(): received nullptr");
+        return __str_rfind<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, traits_type::length(__s));
+    }
+
+    // find_first_of
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_of(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_first_of(): received nullptr");
+        return __str_find_first_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s.data(), __pos, __s.size());
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_of(_CharT __c, size_type __pos = 0) const _NOEXCEPT
+    { return find(__c, __pos); }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_first_of(): received nullptr");
+        return __str_find_first_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, __n);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_of(const _CharT* __s, size_type __pos=0) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_first_of(): received nullptr");
+        return __str_find_first_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, traits_type::length(__s));
+    }
+
+    // find_last_of
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_of(basic_string_view __s, size_type __pos=npos) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_last_of(): received nullptr");
+        return __str_find_last_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s.data(), __pos, __s.size());
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_of(_CharT __c, size_type __pos = npos) const _NOEXCEPT
+    { return rfind(__c, __pos); }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_last_of(): received nullptr");
+        return __str_find_last_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, __n);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_of(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_last_of(): received nullptr");
+        return __str_find_last_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, traits_type::length(__s));
+    }
+
+    // find_first_not_of
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_not_of(basic_string_view __s, size_type __pos=0) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_first_not_of(): received nullptr");
+        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s.data(), __pos, __s.size());
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_not_of(_CharT __c, size_type __pos=0) const _NOEXCEPT
+    {
+        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __c, __pos);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_first_not_of(): received nullptr");
+        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, __n);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_first_not_of(const _CharT* __s, size_type __pos=0) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_first_not_of(): received nullptr");
+        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, traits_type::length(__s));
+    }
+
+    // find_last_not_of
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_not_of(basic_string_view __s, size_type __pos=npos) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_last_not_of(): received nullptr");
+        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s.data(), __pos, __s.size());
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_not_of(_CharT __c, size_type __pos=npos) const _NOEXCEPT
+    {
+        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __c, __pos);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_last_not_of(): received nullptr");
+        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, __n);
+    }
+
+    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+    size_type find_last_not_of(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
+    {
+        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_last_not_of(): received nullptr");
+        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
+            (data(), size(), __s, __pos, traits_type::length(__s));
+    }
+
 //WARN: disabled std guards in order to allow using these options without switching to new std
 //#if _LIBCPP_STD_VER > 17
-    constexpr _LIBCPP_INLINE_VISIBILITY 
-    bool starts_with(basic_string_view __s) const noexcept 
-    { return size() >= __s.size() && compare(0, __s.size(), __s) == 0; } 
- 
-    constexpr _LIBCPP_INLINE_VISIBILITY 
-    bool starts_with(value_type __c) const noexcept 
-    { return !empty() && _Traits::eq(front(), __c); } 
- 
-    constexpr _LIBCPP_INLINE_VISIBILITY 
-    bool starts_with(const value_type* __s) const noexcept 
-    { return starts_with(basic_string_view(__s)); } 
- 
-    constexpr _LIBCPP_INLINE_VISIBILITY 
-    bool ends_with(basic_string_view __s) const noexcept 
-    { return size() >= __s.size() && compare(size() - __s.size(), npos, __s) == 0; } 
- 
-    constexpr _LIBCPP_INLINE_VISIBILITY 
-    bool ends_with(value_type __c) const noexcept 
-    { return !empty() && _Traits::eq(back(), __c); } 
- 
-    constexpr _LIBCPP_INLINE_VISIBILITY 
-    bool ends_with(const value_type* __s) const noexcept 
-    { return ends_with(basic_string_view(__s)); } 
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool starts_with(basic_string_view __s) const noexcept
+    { return size() >= __s.size() && compare(0, __s.size(), __s) == 0; }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool starts_with(value_type __c) const noexcept
+    { return !empty() && _Traits::eq(front(), __c); }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool starts_with(const value_type* __s) const noexcept
+    { return starts_with(basic_string_view(__s)); }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool ends_with(basic_string_view __s) const noexcept
+    { return size() >= __s.size() && compare(size() - __s.size(), npos, __s) == 0; }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool ends_with(value_type __c) const noexcept
+    { return !empty() && _Traits::eq(back(), __c); }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool ends_with(const value_type* __s) const noexcept
+    { return ends_with(basic_string_view(__s)); }
 //#endif
- 
-#if _LIBCPP_STD_VER > 20 
-    constexpr _LIBCPP_INLINE_VISIBILITY 
-    bool contains(basic_string_view __sv) const noexcept 
-    { return find(__sv) != npos; } 
- 
-    constexpr _LIBCPP_INLINE_VISIBILITY 
-    bool contains(value_type __c) const noexcept 
-    { return find(__c) != npos; } 
- 
-    constexpr _LIBCPP_INLINE_VISIBILITY 
-    bool contains(const value_type* __s) const 
-    { return find(__s) != npos; } 
-#endif 
- 
-private: 
-    const   value_type* __data; 
-    size_type           __size; 
-}; 
- 
-#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES) 
-template <class _CharT, class _Traits> 
-inline constexpr bool ranges::enable_view<basic_string_view<_CharT, _Traits>> = true; 
- 
-template <class _CharT, class _Traits> 
-inline constexpr bool ranges::enable_borrowed_range<basic_string_view<_CharT, _Traits> > = true; 
-#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES) 
- 
-// [string.view.deduct] 
- 
-#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES) 
-template <contiguous_iterator _It, sized_sentinel_for<_It> _End> 
-  basic_string_view(_It, _End) -> basic_string_view<iter_value_t<_It>>; 
-#endif 
- 
-// [string.view.comparison] 
-// operator == 
-template<class _CharT, class _Traits> 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator==(basic_string_view<_CharT, _Traits> __lhs, 
-                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT 
-{ 
-    if ( __lhs.size() != __rhs.size()) return false; 
-    return __lhs.compare(__rhs) == 0; 
-} 
- 
-// Workaround for the bug in MSVC and clang on windows. Looks like MSVC generates the same 
-// mangled name for this function as for the previous function. So we introduce 
-// artificial difference to avoid that. 
-#if defined(_LIBCPP_COMPILER_MSVC) || (defined(_WIN32) && defined(_LIBCPP_COMPILER_CLANG)) 
-template<class _CharT, class _Traits, int = 1> 
-#else 
+
+#if _LIBCPP_STD_VER > 20
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool contains(basic_string_view __sv) const noexcept
+    { return find(__sv) != npos; }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool contains(value_type __c) const noexcept
+    { return find(__c) != npos; }
+
+    constexpr _LIBCPP_INLINE_VISIBILITY
+    bool contains(const value_type* __s) const
+    { return find(__s) != npos; }
+#endif
+
+private:
+    const   value_type* __data;
+    size_type           __size;
+};
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+template <class _CharT, class _Traits>
+inline constexpr bool ranges::enable_view<basic_string_view<_CharT, _Traits>> = true;
+
+template <class _CharT, class _Traits>
+inline constexpr bool ranges::enable_borrowed_range<basic_string_view<_CharT, _Traits> > = true;
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+
+// [string.view.deduct]
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_RANGES)
+template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
+  basic_string_view(_It, _End) -> basic_string_view<iter_value_t<_It>>;
+#endif
+
+// [string.view.comparison]
+// operator ==
 template<class _CharT, class _Traits>
-#endif 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator==(basic_string_view<_CharT, _Traits> __lhs, 
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator==(basic_string_view<_CharT, _Traits> __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    if ( __lhs.size() != __rhs.size()) return false;
+    return __lhs.compare(__rhs) == 0;
+}
+
+// Workaround for the bug in MSVC and clang on windows. Looks like MSVC generates the same
+// mangled name for this function as for the previous function. So we introduce
+// artificial difference to avoid that.
+#if defined(_LIBCPP_COMPILER_MSVC) || (defined(_WIN32) && defined(_LIBCPP_COMPILER_CLANG))
+template<class _CharT, class _Traits, int = 1>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator==(basic_string_view<_CharT, _Traits> __lhs,
                 typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
-{ 
-    if ( __lhs.size() != __rhs.size()) return false; 
-    return __lhs.compare(__rhs) == 0; 
-} 
- 
-#if defined(_LIBCPP_COMPILER_MSVC) || (defined(_WIN32) && defined(_LIBCPP_COMPILER_CLANG)) 
-template<class _CharT, class _Traits, int = 2> 
-#else 
+{
+    if ( __lhs.size() != __rhs.size()) return false;
+    return __lhs.compare(__rhs) == 0;
+}
+
+#if defined(_LIBCPP_COMPILER_MSVC) || (defined(_WIN32) && defined(_LIBCPP_COMPILER_CLANG))
+template<class _CharT, class _Traits, int = 2>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator==(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    if ( __lhs.size() != __rhs.size()) return false;
+    return __lhs.compare(__rhs) == 0;
+}
+
+
+// operator !=
 template<class _CharT, class _Traits>
-#endif 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator==(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs, 
-                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT 
-{ 
-    if ( __lhs.size() != __rhs.size()) return false; 
-    return __lhs.compare(__rhs) == 0; 
-} 
- 
- 
-// operator != 
-template<class _CharT, class _Traits> 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator!=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT 
-{ 
-    if ( __lhs.size() != __rhs.size()) 
-        return true; 
-    return __lhs.compare(__rhs) != 0; 
-} 
- 
- 
-#ifdef _LIBCPP_COMPILER_MSVC 
-template<class _CharT, class _Traits, int = 1> 
-#else 
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator!=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    if ( __lhs.size() != __rhs.size())
+        return true;
+    return __lhs.compare(__rhs) != 0;
+}
+
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 1>
+#else
 template<class _CharT, class _Traits>
-#endif 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator!=(basic_string_view<_CharT, _Traits> __lhs, 
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator!=(basic_string_view<_CharT, _Traits> __lhs,
                 typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
-{ 
-    if ( __lhs.size() != __rhs.size()) 
-        return true; 
-    return __lhs.compare(__rhs) != 0; 
-} 
- 
-#ifdef _LIBCPP_COMPILER_MSVC 
-template<class _CharT, class _Traits, int = 2> 
-#else 
+{
+    if ( __lhs.size() != __rhs.size())
+        return true;
+    return __lhs.compare(__rhs) != 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 2>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator!=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    if ( __lhs.size() != __rhs.size())
+        return true;
+    return __lhs.compare(__rhs) != 0;
+}
+
+
+// operator <
 template<class _CharT, class _Traits>
-#endif 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator!=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs, 
-                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT 
-{ 
-    if ( __lhs.size() != __rhs.size()) 
-        return true; 
-    return __lhs.compare(__rhs) != 0; 
-} 
- 
- 
-// operator < 
-template<class _CharT, class _Traits> 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator<(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT 
-{ 
-    return __lhs.compare(__rhs) < 0; 
-} 
- 
-#ifdef _LIBCPP_COMPILER_MSVC 
-template<class _CharT, class _Traits, int = 1> 
-#else 
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator<(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) < 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 1>
+#else
 template<class _CharT, class _Traits>
-#endif 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator<(basic_string_view<_CharT, _Traits> __lhs, 
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator<(basic_string_view<_CharT, _Traits> __lhs,
                 typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
-{ 
-    return __lhs.compare(__rhs) < 0; 
-} 
- 
-#ifdef _LIBCPP_COMPILER_MSVC 
-template<class _CharT, class _Traits, int = 2> 
-#else 
+{
+    return __lhs.compare(__rhs) < 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 2>
+#else
 template<class _CharT, class _Traits>
-#endif 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator<(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs, 
-                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT 
-{ 
-    return __lhs.compare(__rhs) < 0; 
-} 
- 
- 
-// operator > 
-template<class _CharT, class _Traits> 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator> (basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT 
-{ 
-    return __lhs.compare(__rhs) > 0; 
-} 
- 
-#ifdef _LIBCPP_COMPILER_MSVC 
-template<class _CharT, class _Traits, int = 1> 
-#else 
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator<(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) < 0;
+}
+
+
+// operator >
+template<class _CharT, class _Traits>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator> (basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) > 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 1>
+#else
 template<class _CharT, class _Traits>
-#endif 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator>(basic_string_view<_CharT, _Traits> __lhs, 
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator>(basic_string_view<_CharT, _Traits> __lhs,
                 typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
-{ 
-    return __lhs.compare(__rhs) > 0; 
-} 
- 
-#ifdef _LIBCPP_COMPILER_MSVC 
-template<class _CharT, class _Traits, int = 2> 
-#else 
+{
+    return __lhs.compare(__rhs) > 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 2>
+#else
 template<class _CharT, class _Traits>
-#endif 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator>(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs, 
-                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT 
-{ 
-    return __lhs.compare(__rhs) > 0; 
-} 
- 
- 
-// operator <= 
-template<class _CharT, class _Traits> 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator<=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT 
-{ 
-    return __lhs.compare(__rhs) <= 0; 
-} 
- 
-#ifdef _LIBCPP_COMPILER_MSVC 
-template<class _CharT, class _Traits, int = 1> 
-#else 
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator>(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) > 0;
+}
+
+
+// operator <=
 template<class _CharT, class _Traits>
-#endif 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator<=(basic_string_view<_CharT, _Traits> __lhs, 
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator<=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) <= 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 1>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator<=(basic_string_view<_CharT, _Traits> __lhs,
                 typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
-{ 
-    return __lhs.compare(__rhs) <= 0; 
-} 
- 
-#ifdef _LIBCPP_COMPILER_MSVC 
-template<class _CharT, class _Traits, int = 2> 
-#else 
+{
+    return __lhs.compare(__rhs) <= 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 2>
+#else
 template<class _CharT, class _Traits>
-#endif 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator<=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs, 
-                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT 
-{ 
-    return __lhs.compare(__rhs) <= 0; 
-} 
- 
- 
-// operator >= 
-template<class _CharT, class _Traits> 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator>=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT 
-{ 
-    return __lhs.compare(__rhs) >= 0; 
-} 
- 
- 
-#ifdef _LIBCPP_COMPILER_MSVC 
-template<class _CharT, class _Traits, int = 1> 
-#else 
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator<=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) <= 0;
+}
+
+
+// operator >=
+template<class _CharT, class _Traits>
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator>=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) >= 0;
+}
+
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 1>
+#else
 template<class _CharT, class _Traits>
-#endif 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator>=(basic_string_view<_CharT, _Traits> __lhs, 
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator>=(basic_string_view<_CharT, _Traits> __lhs,
                 typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
-{ 
-    return __lhs.compare(__rhs) >= 0; 
-} 
- 
-#ifdef _LIBCPP_COMPILER_MSVC 
-template<class _CharT, class _Traits, int = 2> 
-#else 
+{
+    return __lhs.compare(__rhs) >= 0;
+}
+
+#ifdef _LIBCPP_COMPILER_MSVC
+template<class _CharT, class _Traits, int = 2>
+#else
+template<class _CharT, class _Traits>
+#endif
+_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
+bool operator>=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
+                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
+{
+    return __lhs.compare(__rhs) >= 0;
+}
+
+
 template<class _CharT, class _Traits>
-#endif 
-_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY 
-bool operator>=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs, 
-                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT 
-{ 
-    return __lhs.compare(__rhs) >= 0; 
-} 
- 
- 
-template<class _CharT, class _Traits> 
-basic_ostream<_CharT, _Traits>& 
-operator<<(basic_ostream<_CharT, _Traits>& __os, 
-           basic_string_view<_CharT, _Traits> __str); 
- 
-// [string.view.hash] 
-template<class _CharT> 
-struct _LIBCPP_TEMPLATE_VIS hash<basic_string_view<_CharT, char_traits<_CharT> > > 
-    : public unary_function<basic_string_view<_CharT, char_traits<_CharT> >, size_t> 
-{ 
+basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os,
+           basic_string_view<_CharT, _Traits> __str);
+
+// [string.view.hash]
+template<class _CharT>
+struct _LIBCPP_TEMPLATE_VIS hash<basic_string_view<_CharT, char_traits<_CharT> > >
+    : public unary_function<basic_string_view<_CharT, char_traits<_CharT> >, size_t>
+{
     _LIBCPP_INLINE_VISIBILITY
-    size_t operator()(const basic_string_view<_CharT, char_traits<_CharT> > __val) const _NOEXCEPT { 
+    size_t operator()(const basic_string_view<_CharT, char_traits<_CharT> > __val) const _NOEXCEPT {
         return __do_string_hash(__val.data(), __val.data() + __val.size());
     }
-}; 
- 
- 
-#if _LIBCPP_STD_VER > 11 
-inline namespace literals 
-{ 
-  inline namespace string_view_literals 
-  { 
-    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR 
-    basic_string_view<char> operator "" sv(const char *__str, size_t __len) _NOEXCEPT 
-    { 
-        return basic_string_view<char> (__str, __len); 
-    } 
- 
-#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS 
-    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR 
-    basic_string_view<wchar_t> operator "" sv(const wchar_t *__str, size_t __len) _NOEXCEPT 
-    { 
-        return basic_string_view<wchar_t> (__str, __len); 
-    } 
-#endif 
- 
-#ifndef _LIBCPP_HAS_NO_CHAR8_T 
-    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR 
+};
+
+
+#if _LIBCPP_STD_VER > 11
+inline namespace literals
+{
+  inline namespace string_view_literals
+  {
+    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    basic_string_view<char> operator "" sv(const char *__str, size_t __len) _NOEXCEPT
+    {
+        return basic_string_view<char> (__str, __len);
+    }
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    basic_string_view<wchar_t> operator "" sv(const wchar_t *__str, size_t __len) _NOEXCEPT
+    {
+        return basic_string_view<wchar_t> (__str, __len);
+    }
+#endif
+
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
     basic_string_view<char8_t> operator "" sv(const char8_t *__str, size_t __len) _NOEXCEPT
     {
         return basic_string_view<char8_t> (__str, __len);
@@ -968,25 +968,25 @@ inline namespace literals
 #endif
 
     inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
-    basic_string_view<char16_t> operator "" sv(const char16_t *__str, size_t __len) _NOEXCEPT 
-    { 
-        return basic_string_view<char16_t> (__str, __len); 
-    } 
- 
-    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR 
-    basic_string_view<char32_t> operator "" sv(const char32_t *__str, size_t __len) _NOEXCEPT 
-    { 
-        return basic_string_view<char32_t> (__str, __len); 
-    } 
-  } 
-} 
-#endif 
-_LIBCPP_END_NAMESPACE_STD 
- 
-#ifdef _LIBCPP_COMPILER_MSVC 
-#pragma warning ( pop ) 
-#endif 
- 
-_LIBCPP_POP_MACROS 
- 
-#endif // _LIBCPP_STRING_VIEW 
+    basic_string_view<char16_t> operator "" sv(const char16_t *__str, size_t __len) _NOEXCEPT
+    {
+        return basic_string_view<char16_t> (__str, __len);
+    }
+
+    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+    basic_string_view<char32_t> operator "" sv(const char32_t *__str, size_t __len) _NOEXCEPT
+    {
+        return basic_string_view<char32_t> (__str, __len);
+    }
+  }
+}
+#endif
+_LIBCPP_END_NAMESPACE_STD
+
+#ifdef _LIBCPP_COMPILER_MSVC
+#pragma warning ( pop )
+#endif
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP_STRING_VIEW