xref: /aosp_15_r20/external/cronet/third_party/libc++/src/include/string_view (revision 6777b5387eb2ff775bb5750e3f5d96f37fb7352b)
1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_STRING_VIEW
11#define _LIBCPP_STRING_VIEW
12
13// clang-format off
14
15/*
16
17    string_view synopsis
18
19#include <compare>
20
21namespace std {
22
23    // 7.2, Class template basic_string_view
24    template<class charT, class traits = char_traits<charT>>
25        class basic_string_view;
26
27    template<class charT, class traits>
28    inline constexpr bool ranges::enable_view<basic_string_view<charT, traits>> = true;
29
30    template<class charT, class traits>
31    inline constexpr bool ranges::enable_borrowed_range<basic_string_view<charT, traits>> = true;  // C++20
32
33    // 7.9, basic_string_view non-member comparison functions
34    template<class charT, class traits>
35    constexpr bool operator==(basic_string_view<charT, traits> x,
36                              basic_string_view<charT, traits> y) noexcept;
37    template<class charT, class traits>                                                            // Removed in C++20
38    constexpr bool operator!=(basic_string_view<charT, traits> x,
39                              basic_string_view<charT, traits> y) noexcept;
40    template<class charT, class traits>                                                            // Removed in C++20
41    constexpr bool operator< (basic_string_view<charT, traits> x,
42                                 basic_string_view<charT, traits> y) noexcept;
43    template<class charT, class traits>                                                            // Removed in C++20
44    constexpr bool operator> (basic_string_view<charT, traits> x,
45                              basic_string_view<charT, traits> y) noexcept;
46    template<class charT, class traits>                                                            // Removed in C++20
47    constexpr bool operator<=(basic_string_view<charT, traits> x,
48                                 basic_string_view<charT, traits> y) noexcept;
49    template<class charT, class traits>                                                            // Removed in C++20
50    constexpr bool operator>=(basic_string_view<charT, traits> x,
51                              basic_string_view<charT, traits> y) noexcept;
52    template<class charT, class traits>                                                            // Since C++20
53    constexpr see below operator<=>(basic_string_view<charT, traits> x,
54                                    basic_string_view<charT, traits> y) noexcept;
55
56    // see below, sufficient additional overloads of comparison functions
57
58    // 7.10, Inserters and extractors
59    template<class charT, class traits>
60      basic_ostream<charT, traits>&
61        operator<<(basic_ostream<charT, traits>& os,
62                   basic_string_view<charT, traits> str);
63
64    // basic_string_view typedef names
65    typedef basic_string_view<char> string_view;
66    typedef basic_string_view<char8_t> u8string_view; // C++20
67    typedef basic_string_view<char16_t> u16string_view;
68    typedef basic_string_view<char32_t> u32string_view;
69    typedef basic_string_view<wchar_t> wstring_view;
70
71    template<class charT, class traits = char_traits<charT>>
72    class basic_string_view {
73      public:
74      // types
75      typedef traits traits_type;
76      typedef charT value_type;
77      typedef charT* pointer;
78      typedef const charT* const_pointer;
79      typedef charT& reference;
80      typedef const charT& const_reference;
81      typedef implementation-defined const_iterator;
82      typedef const_iterator iterator;
83      typedef reverse_iterator<const_iterator> const_reverse_iterator;
84      typedef const_reverse_iterator reverse_iterator;
85      typedef size_t size_type;
86      typedef ptrdiff_t difference_type;
87      static constexpr size_type npos = size_type(-1);
88
89      // 7.3, basic_string_view constructors and assignment operators
90      constexpr basic_string_view() noexcept;
91      constexpr basic_string_view(const basic_string_view&) noexcept = default;
92      basic_string_view& operator=(const basic_string_view&) noexcept = default;
93      template<class Allocator>
94      constexpr basic_string_view(const charT* str);
95      basic_string_view(nullptr_t) = delete; // C++23
96      constexpr basic_string_view(const charT* str, size_type len);
97      template <class It, class End>
98      constexpr basic_string_view(It begin, End end); // C++20
99      template <class Range>
100      constexpr basic_string_view(Range&& r); // C++23
101
102      // 7.4, basic_string_view iterator support
103      constexpr const_iterator begin() const noexcept;
104      constexpr const_iterator end() const noexcept;
105      constexpr const_iterator cbegin() const noexcept;
106      constexpr const_iterator cend() const noexcept;
107      const_reverse_iterator rbegin() const noexcept;
108      const_reverse_iterator rend() const noexcept;
109      const_reverse_iterator crbegin() const noexcept;
110      const_reverse_iterator crend() const noexcept;
111
112      // 7.5, basic_string_view capacity
113      constexpr size_type size() const noexcept;
114      constexpr size_type length() const noexcept;
115      constexpr size_type max_size() const noexcept;
116      constexpr bool empty() const noexcept;
117
118      // 7.6, basic_string_view element access
119      constexpr const_reference operator[](size_type pos) const;
120      constexpr const_reference at(size_type pos) const;
121      constexpr const_reference front() const;
122      constexpr const_reference back() const;
123      constexpr const_pointer data() const noexcept;
124
125      // 7.7, basic_string_view modifiers
126      constexpr void remove_prefix(size_type n);
127      constexpr void remove_suffix(size_type n);
128      constexpr void swap(basic_string_view& s) noexcept;
129
130      size_type copy(charT* s, size_type n, size_type pos = 0) const;  // constexpr in C++20
131
132      constexpr basic_string_view substr(size_type pos = 0, size_type n = npos) const;
133      constexpr int compare(basic_string_view s) const noexcept;
134      constexpr int compare(size_type pos1, size_type n1, basic_string_view s) const;
135      constexpr int compare(size_type pos1, size_type n1,
136                            basic_string_view s, size_type pos2, size_type n2) const;
137      constexpr int compare(const charT* s) const;
138      constexpr int compare(size_type pos1, size_type n1, const charT* s) const;
139      constexpr int compare(size_type pos1, size_type n1,
140                            const charT* s, size_type n2) const;
141      constexpr size_type find(basic_string_view s, size_type pos = 0) const noexcept;
142      constexpr size_type find(charT c, size_type pos = 0) const noexcept;
143      constexpr size_type find(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
144      constexpr size_type find(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
145      constexpr size_type rfind(basic_string_view s, size_type pos = npos) const noexcept;
146      constexpr size_type rfind(charT c, size_type pos = npos) const noexcept;
147      constexpr size_type rfind(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
148      constexpr size_type rfind(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
149      constexpr size_type find_first_of(basic_string_view s, size_type pos = 0) const noexcept;
150      constexpr size_type find_first_of(charT c, size_type pos = 0) const noexcept;
151      constexpr size_type find_first_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
152      constexpr size_type find_first_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
153      constexpr size_type find_last_of(basic_string_view s, size_type pos = npos) const noexcept;
154      constexpr size_type find_last_of(charT c, size_type pos = npos) const noexcept;
155      constexpr size_type find_last_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
156      constexpr size_type find_last_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
157      constexpr size_type find_first_not_of(basic_string_view s, size_type pos = 0) const noexcept;
158      constexpr size_type find_first_not_of(charT c, size_type pos = 0) const noexcept;
159      constexpr size_type find_first_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
160      constexpr size_type find_first_not_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
161      constexpr size_type find_last_not_of(basic_string_view s, size_type pos = npos) const noexcept;
162      constexpr size_type find_last_not_of(charT c, size_type pos = npos) const noexcept;
163      constexpr size_type find_last_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
164      constexpr size_type find_last_not_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
165
166      constexpr bool starts_with(basic_string_view s) const noexcept; // C++20
167      constexpr bool starts_with(charT c) const noexcept;             // C++20
168      constexpr bool starts_with(const charT* s) const;               // C++20
169      constexpr bool ends_with(basic_string_view s) const noexcept;   // C++20
170      constexpr bool ends_with(charT c) const noexcept;               // C++20
171      constexpr bool ends_with(const charT* s) const;                 // C++20
172
173      constexpr bool contains(basic_string_view s) const noexcept; // C++23
174      constexpr bool contains(charT c) const noexcept;             // C++23
175      constexpr bool contains(const charT* s) const;               // C++23
176
177     private:
178      const_pointer data_;  // exposition only
179      size_type     size_;  // exposition only
180    };
181
182  // basic_string_view deduction guides
183  template<class It, class End>
184    basic_string_view(It, End) -> basic_string_view<iter_value_t<It>>; // C++20
185  template<class Range>
186    basic_string_view(Range&&) -> basic_string_view<ranges::range_value_t<Range>>; // C++23
187
188  // 7.11, Hash support
189  template <class T> struct hash;
190  template <> struct hash<string_view>;
191  template <> struct hash<u8string_view>; // C++20
192  template <> struct hash<u16string_view>;
193  template <> struct hash<u32string_view>;
194  template <> struct hash<wstring_view>;
195
196  constexpr basic_string_view<char>     operator""sv(const char *str,     size_t len) noexcept;
197  constexpr basic_string_view<wchar_t>  operator""sv(const wchar_t *str,  size_t len) noexcept;
198  constexpr basic_string_view<char8_t>  operator""sv(const char8_t *str,  size_t len) noexcept; // C++20
199  constexpr basic_string_view<char16_t> operator""sv(const char16_t *str, size_t len) noexcept;
200  constexpr basic_string_view<char32_t> operator""sv(const char32_t *str, size_t len) noexcept;
201
202}  // namespace std
203
204*/
205
206// clang-format on
207
208#include <__algorithm/min.h>
209#include <__assert>
210#include <__config>
211#include <__functional/hash.h>
212#include <__functional/unary_function.h>
213#include <__fwd/string_view.h>
214#include <__iterator/bounded_iter.h>
215#include <__iterator/concepts.h>
216#include <__iterator/iterator_traits.h>
217#include <__iterator/reverse_iterator.h>
218#include <__iterator/wrap_iter.h>
219#include <__memory/pointer_traits.h>
220#include <__ranges/concepts.h>
221#include <__ranges/data.h>
222#include <__ranges/enable_borrowed_range.h>
223#include <__ranges/enable_view.h>
224#include <__ranges/size.h>
225#include <__string/char_traits.h>
226#include <__type_traits/is_array.h>
227#include <__type_traits/is_convertible.h>
228#include <__type_traits/is_same.h>
229#include <__type_traits/is_standard_layout.h>
230#include <__type_traits/is_trivial.h>
231#include <__type_traits/remove_cvref.h>
232#include <__type_traits/remove_reference.h>
233#include <__type_traits/type_identity.h>
234#include <cstddef>
235#include <iosfwd>
236#include <limits>
237#include <stdexcept>
238#include <version>
239
240// standard-mandated includes
241
242// [iterator.range]
243#include <__iterator/access.h>
244#include <__iterator/data.h>
245#include <__iterator/empty.h>
246#include <__iterator/reverse_access.h>
247#include <__iterator/size.h>
248
249// [string.view.synop]
250#include <compare>
251
252#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
253#  pragma GCC system_header
254#endif
255
256_LIBCPP_PUSH_MACROS
257#include <__undef_macros>
258
259_LIBCPP_BEGIN_NAMESPACE_STD
260
261// TODO: This is a workaround for some vendors to carry a downstream diff to accept `nullptr` in
262//       string_view constructors. This can be refactored when this exact form isn't needed anymore.
263template <class _Traits>
264_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR inline size_t
265__char_traits_length_checked(const typename _Traits::char_type* __s) _NOEXCEPT {
266  // This needs to be a single statement for C++11 constexpr
267  return _LIBCPP_ASSERT_NON_NULL(
268             __s != nullptr, "null pointer passed to non-null argument of char_traits<...>::length"),
269         _Traits::length(__s);
270}
271
272template <class _CharT, class _Traits>
273class basic_string_view {
274public:
275  // types
276  using traits_type     = _Traits;
277  using value_type      = _CharT;
278  using pointer         = _CharT*;
279  using const_pointer   = const _CharT*;
280  using reference       = _CharT&;
281  using const_reference = const _CharT&;
282#if defined(_LIBCPP_ABI_BOUNDED_ITERATORS)
283  using const_iterator = __bounded_iter<const_pointer>;
284#elif defined(_LIBCPP_ABI_USE_WRAP_ITER_IN_STD_STRING_VIEW)
285  using const_iterator = __wrap_iter<const_pointer>;
286#else
287  using const_iterator = const_pointer;
288#endif
289  using iterator                                = const_iterator;
290  using const_reverse_iterator                  = std::reverse_iterator<const_iterator>;
291  using reverse_iterator                        = const_reverse_iterator;
292  using size_type                               = size_t;
293  using difference_type                         = ptrdiff_t;
294  static _LIBCPP_CONSTEXPR const size_type npos = -1; // size_type(-1);
295
296  static_assert((!is_array<value_type>::value), "Character type of basic_string_view must not be an array");
297  static_assert((is_standard_layout<value_type>::value), "Character type of basic_string_view must be standard-layout");
298  static_assert((is_trivial<value_type>::value), "Character type of basic_string_view must be trivial");
299  static_assert((is_same<_CharT, typename traits_type::char_type>::value),
300                "traits_type::char_type must be the same type as CharT");
301
302  // [string.view.cons], construct/copy
303  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI basic_string_view() _NOEXCEPT : __data_(nullptr), __size_(0) {}
304
305  _LIBCPP_HIDE_FROM_ABI basic_string_view(const basic_string_view&) _NOEXCEPT = default;
306
307  _LIBCPP_HIDE_FROM_ABI basic_string_view& operator=(const basic_string_view&) _NOEXCEPT = default;
308
309  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI basic_string_view(const _CharT* __s, size_type __len) _NOEXCEPT
310      : __data_(__s),
311        __size_(__len) {
312#if _LIBCPP_STD_VER >= 14
313    // Allocations must fit in `ptrdiff_t` for pointer arithmetic to work. If `__len` exceeds it, the input
314    // range could not have been valid. Most likely the caller underflowed some arithmetic and inadvertently
315    // passed in a negative length.
316    _LIBCPP_ASSERT_VALID_INPUT_RANGE(
317        __len <= static_cast<size_type>(numeric_limits<difference_type>::max()),
318        "string_view::string_view(_CharT *, size_t): length does not fit in difference_type");
319    _LIBCPP_ASSERT_NON_NULL(
320        __len == 0 || __s != nullptr, "string_view::string_view(_CharT *, size_t): received nullptr");
321#endif
322  }
323
324#if _LIBCPP_STD_VER >= 20
325  template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
326    requires(is_same_v<iter_value_t<_It>, _CharT> && !is_convertible_v<_End, size_type>)
327  constexpr _LIBCPP_HIDE_FROM_ABI basic_string_view(_It __begin, _End __end)
328      : __data_(std::to_address(__begin)), __size_(__end - __begin) {
329    _LIBCPP_ASSERT_VALID_INPUT_RANGE(
330        (__end - __begin) >= 0, "std::string_view::string_view(iterator, sentinel) received invalid range");
331  }
332#endif // _LIBCPP_STD_VER >= 20
333
334#if _LIBCPP_STD_VER >= 23
335  template <class _Range>
336    requires(!is_same_v<remove_cvref_t<_Range>, basic_string_view> && ranges::contiguous_range<_Range> &&
337             ranges::sized_range<_Range> && is_same_v<ranges::range_value_t<_Range>, _CharT> &&
338             !is_convertible_v<_Range, const _CharT*> &&
339             (!requires(remove_cvref_t<_Range>& __d) { __d.operator std::basic_string_view<_CharT, _Traits>(); }))
340  constexpr explicit _LIBCPP_HIDE_FROM_ABI basic_string_view(_Range&& __r)
341      : __data_(ranges::data(__r)), __size_(ranges::size(__r)) {}
342#endif // _LIBCPP_STD_VER >= 23
343
344  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI basic_string_view(const _CharT* __s)
345      : __data_(__s), __size_(std::__char_traits_length_checked<_Traits>(__s)) {}
346
347#if _LIBCPP_STD_VER >= 23
348  basic_string_view(nullptr_t) = delete;
349#endif
350
351  // [string.view.iterators], iterators
352  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return cbegin(); }
353
354  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return cend(); }
355
356  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT {
357#ifdef _LIBCPP_ABI_BOUNDED_ITERATORS
358    return std::__make_bounded_iter(data(), data(), data() + size());
359#else
360    return const_iterator(__data_);
361#endif
362  }
363
364  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT {
365#ifdef _LIBCPP_ABI_BOUNDED_ITERATORS
366    return std::__make_bounded_iter(data() + size(), data(), data() + size());
367#else
368    return const_iterator(__data_ + __size_);
369#endif
370  }
371
372  _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rbegin() const _NOEXCEPT {
373    return const_reverse_iterator(cend());
374  }
375
376  _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rend() const _NOEXCEPT {
377    return const_reverse_iterator(cbegin());
378  }
379
380  _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crbegin() const _NOEXCEPT {
381    return const_reverse_iterator(cend());
382  }
383
384  _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crend() const _NOEXCEPT {
385    return const_reverse_iterator(cbegin());
386  }
387
388  // [string.view.capacity], capacity
389  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __size_; }
390
391  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI size_type length() const _NOEXCEPT { return __size_; }
392
393  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT {
394    return numeric_limits<size_type>::max() / sizeof(value_type);
395  }
396
397  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT {
398    return __size_ == 0;
399  }
400
401  // [string.view.access], element access
402  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_reference operator[](size_type __pos) const _NOEXCEPT {
403    return _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__pos < size(), "string_view[] index out of bounds"), __data_[__pos];
404  }
405
406  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_reference at(size_type __pos) const {
407    return __pos >= size() ? (__throw_out_of_range("string_view::at"), __data_[0]) : __data_[__pos];
408  }
409
410  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_reference front() const _NOEXCEPT {
411    return _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string_view::front(): string is empty"), __data_[0];
412  }
413
414  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_reference back() const _NOEXCEPT {
415    return _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string_view::back(): string is empty"), __data_[__size_ - 1];
416  }
417
418  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_pointer data() const _NOEXCEPT { return __data_; }
419
420  // [string.view.modifiers], modifiers:
421  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI void remove_prefix(size_type __n) _NOEXCEPT {
422    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__n <= size(), "remove_prefix() can't remove more than size()");
423    __data_ += __n;
424    __size_ -= __n;
425  }
426
427  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI void remove_suffix(size_type __n) _NOEXCEPT {
428    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__n <= size(), "remove_suffix() can't remove more than size()");
429    __size_ -= __n;
430  }
431
432  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI void swap(basic_string_view& __other) _NOEXCEPT {
433    const value_type* __p = __data_;
434    __data_               = __other.__data_;
435    __other.__data_       = __p;
436
437    size_type __sz  = __size_;
438    __size_         = __other.__size_;
439    __other.__size_ = __sz;
440  }
441
442  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
443  copy(_CharT* __s, size_type __n, size_type __pos = 0) const {
444    if (__pos > size())
445      __throw_out_of_range("string_view::copy");
446    size_type __rlen = std::min(__n, size() - __pos);
447    _Traits::copy(__s, data() + __pos, __rlen);
448    return __rlen;
449  }
450
451  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI basic_string_view substr(size_type __pos = 0, size_type __n = npos) const {
452    return __pos > size() ? (__throw_out_of_range("string_view::substr"), basic_string_view())
453                          : basic_string_view(data() + __pos, std::min(__n, size() - __pos));
454  }
455
456  _LIBCPP_CONSTEXPR_SINCE_CXX14 int compare(basic_string_view __sv) const _NOEXCEPT {
457    size_type __rlen = std::min(size(), __sv.size());
458    int __retval     = _Traits::compare(data(), __sv.data(), __rlen);
459    if (__retval == 0) // first __rlen chars matched
460      __retval = size() == __sv.size() ? 0 : (size() < __sv.size() ? -1 : 1);
461    return __retval;
462  }
463
464  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int
465  compare(size_type __pos1, size_type __n1, basic_string_view __sv) const {
466    return substr(__pos1, __n1).compare(__sv);
467  }
468
469  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int
470  compare(size_type __pos1, size_type __n1, basic_string_view __sv, size_type __pos2, size_type __n2) const {
471    return substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
472  }
473
474  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int compare(const _CharT* __s) const _NOEXCEPT {
475    return compare(basic_string_view(__s));
476  }
477
478  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int
479  compare(size_type __pos1, size_type __n1, const _CharT* __s) const {
480    return substr(__pos1, __n1).compare(basic_string_view(__s));
481  }
482
483  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int
484  compare(size_type __pos1, size_type __n1, const _CharT* __s, size_type __n2) const {
485    return substr(__pos1, __n1).compare(basic_string_view(__s, __n2));
486  }
487
488  // find
489  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
490  find(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT {
491    _LIBCPP_ASSERT_NON_NULL(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
492    return std::__str_find<value_type, size_type, traits_type, npos>(data(), size(), __s.data(), __pos, __s.size());
493  }
494
495  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type find(_CharT __c, size_type __pos = 0) const _NOEXCEPT {
496    return std::__str_find<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
497  }
498
499  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
500  find(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
501    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find(): received nullptr");
502    return std::__str_find<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
503  }
504
505  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
506  find(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT {
507    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find(): received nullptr");
508    return std::__str_find<value_type, size_type, traits_type, npos>(
509        data(), size(), __s, __pos, traits_type::length(__s));
510  }
511
512  // rfind
513  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
514  rfind(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT {
515    _LIBCPP_ASSERT_NON_NULL(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
516    return std::__str_rfind<value_type, size_type, traits_type, npos>(data(), size(), __s.data(), __pos, __s.size());
517  }
518
519  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
520  rfind(_CharT __c, size_type __pos = npos) const _NOEXCEPT {
521    return std::__str_rfind<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
522  }
523
524  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
525  rfind(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
526    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::rfind(): received nullptr");
527    return std::__str_rfind<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
528  }
529
530  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
531  rfind(const _CharT* __s, size_type __pos = npos) const _NOEXCEPT {
532    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::rfind(): received nullptr");
533    return std::__str_rfind<value_type, size_type, traits_type, npos>(
534        data(), size(), __s, __pos, traits_type::length(__s));
535  }
536
537  // find_first_of
538  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
539  find_first_of(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT {
540    _LIBCPP_ASSERT_NON_NULL(__s.size() == 0 || __s.data() != nullptr, "string_view::find_first_of(): received nullptr");
541    return std::__str_find_first_of<value_type, size_type, traits_type, npos>(
542        data(), size(), __s.data(), __pos, __s.size());
543  }
544
545  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
546  find_first_of(_CharT __c, size_type __pos = 0) const _NOEXCEPT {
547    return find(__c, __pos);
548  }
549
550  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
551  find_first_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
552    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find_first_of(): received nullptr");
553    return std::__str_find_first_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
554  }
555
556  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
557  find_first_of(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT {
558    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find_first_of(): received nullptr");
559    return std::__str_find_first_of<value_type, size_type, traits_type, npos>(
560        data(), size(), __s, __pos, traits_type::length(__s));
561  }
562
563  // find_last_of
564  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
565  find_last_of(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT {
566    _LIBCPP_ASSERT_NON_NULL(__s.size() == 0 || __s.data() != nullptr, "string_view::find_last_of(): received nullptr");
567    return std::__str_find_last_of<value_type, size_type, traits_type, npos>(
568        data(), size(), __s.data(), __pos, __s.size());
569  }
570
571  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
572  find_last_of(_CharT __c, size_type __pos = npos) const _NOEXCEPT {
573    return rfind(__c, __pos);
574  }
575
576  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
577  find_last_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
578    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find_last_of(): received nullptr");
579    return std::__str_find_last_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
580  }
581
582  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
583  find_last_of(const _CharT* __s, size_type __pos = npos) const _NOEXCEPT {
584    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find_last_of(): received nullptr");
585    return std::__str_find_last_of<value_type, size_type, traits_type, npos>(
586        data(), size(), __s, __pos, traits_type::length(__s));
587  }
588
589  // find_first_not_of
590  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
591  find_first_not_of(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT {
592    _LIBCPP_ASSERT_NON_NULL(
593        __s.size() == 0 || __s.data() != nullptr, "string_view::find_first_not_of(): received nullptr");
594    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(
595        data(), size(), __s.data(), __pos, __s.size());
596  }
597
598  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
599  find_first_not_of(_CharT __c, size_type __pos = 0) const _NOEXCEPT {
600    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
601  }
602
603  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
604  find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
605    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find_first_not_of(): received nullptr");
606    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
607  }
608
609  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
610  find_first_not_of(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT {
611    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find_first_not_of(): received nullptr");
612    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(
613        data(), size(), __s, __pos, traits_type::length(__s));
614  }
615
616  // find_last_not_of
617  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
618  find_last_not_of(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT {
619    _LIBCPP_ASSERT_NON_NULL(
620        __s.size() == 0 || __s.data() != nullptr, "string_view::find_last_not_of(): received nullptr");
621    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(
622        data(), size(), __s.data(), __pos, __s.size());
623  }
624
625  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
626  find_last_not_of(_CharT __c, size_type __pos = npos) const _NOEXCEPT {
627    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
628  }
629
630  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
631  find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
632    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find_last_not_of(): received nullptr");
633    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
634  }
635
636  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
637  find_last_not_of(const _CharT* __s, size_type __pos = npos) const _NOEXCEPT {
638    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find_last_not_of(): received nullptr");
639    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(
640        data(), size(), __s, __pos, traits_type::length(__s));
641  }
642
643#if _LIBCPP_STD_VER >= 20
644  constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(basic_string_view __s) const noexcept {
645    return size() >= __s.size() && compare(0, __s.size(), __s) == 0;
646  }
647
648  constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(value_type __c) const noexcept {
649    return !empty() && _Traits::eq(front(), __c);
650  }
651
652  constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(const value_type* __s) const noexcept {
653    return starts_with(basic_string_view(__s));
654  }
655
656  constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(basic_string_view __s) const noexcept {
657    return size() >= __s.size() && compare(size() - __s.size(), npos, __s) == 0;
658  }
659
660  constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(value_type __c) const noexcept {
661    return !empty() && _Traits::eq(back(), __c);
662  }
663
664  constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(const value_type* __s) const noexcept {
665    return ends_with(basic_string_view(__s));
666  }
667#endif
668
669#if _LIBCPP_STD_VER >= 23
670  constexpr _LIBCPP_HIDE_FROM_ABI bool contains(basic_string_view __sv) const noexcept { return find(__sv) != npos; }
671
672  constexpr _LIBCPP_HIDE_FROM_ABI bool contains(value_type __c) const noexcept { return find(__c) != npos; }
673
674  constexpr _LIBCPP_HIDE_FROM_ABI bool contains(const value_type* __s) const { return find(__s) != npos; }
675#endif
676
677private:
678  const value_type* __data_;
679  size_type __size_;
680};
681_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(basic_string_view);
682
683#if _LIBCPP_STD_VER >= 20
684template <class _CharT, class _Traits>
685inline constexpr bool ranges::enable_view<basic_string_view<_CharT, _Traits>> = true;
686
687template <class _CharT, class _Traits>
688inline constexpr bool ranges::enable_borrowed_range<basic_string_view<_CharT, _Traits> > = true;
689#endif // _LIBCPP_STD_VER >= 20
690
691// [string.view.deduct]
692
693#if _LIBCPP_STD_VER >= 20
694template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
695basic_string_view(_It, _End) -> basic_string_view<iter_value_t<_It>>;
696#endif // _LIBCPP_STD_VER >= 20
697
698#if _LIBCPP_STD_VER >= 23
699template <ranges::contiguous_range _Range>
700basic_string_view(_Range) -> basic_string_view<ranges::range_value_t<_Range>>;
701#endif
702
703// [string.view.comparison]
704
705#if _LIBCPP_STD_VER >= 20
706
707template <class _CharT, class _Traits>
708_LIBCPP_HIDE_FROM_ABI constexpr bool operator==(basic_string_view<_CharT, _Traits> __lhs,
709                                                type_identity_t<basic_string_view<_CharT, _Traits>> __rhs) noexcept {
710  if (__lhs.size() != __rhs.size())
711    return false;
712  return __lhs.compare(__rhs) == 0;
713}
714
715template <class _CharT, class _Traits>
716_LIBCPP_HIDE_FROM_ABI constexpr auto operator<=>(basic_string_view<_CharT, _Traits> __lhs,
717                                                 type_identity_t<basic_string_view<_CharT, _Traits>> __rhs) noexcept {
718  if constexpr (requires { typename _Traits::comparison_category; }) {
719    // [string.view]/4
720    static_assert(
721        __comparison_category<typename _Traits::comparison_category>, "return type is not a comparison category type");
722    return static_cast<typename _Traits::comparison_category>(__lhs.compare(__rhs) <=> 0);
723  } else {
724    return static_cast<weak_ordering>(__lhs.compare(__rhs) <=> 0);
725  }
726}
727
728#else
729
730// operator ==
731
732template <class _CharT, class _Traits>
733_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
734operator==(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
735  if (__lhs.size() != __rhs.size())
736    return false;
737  return __lhs.compare(__rhs) == 0;
738}
739
740// The dummy default template parameters are used to work around a MSVC issue with mangling, see VSO-409326 for details.
741// This applies to the other sufficient overloads below for the other comparison operators.
742template <class _CharT, class _Traits, int = 1>
743_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
744operator==(basic_string_view<_CharT, _Traits> __lhs,
745           __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
746  if (__lhs.size() != __rhs.size())
747    return false;
748  return __lhs.compare(__rhs) == 0;
749}
750
751template <class _CharT, class _Traits, int = 2>
752_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
753operator==(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
754           basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
755  if (__lhs.size() != __rhs.size())
756    return false;
757  return __lhs.compare(__rhs) == 0;
758}
759
760// operator !=
761template <class _CharT, class _Traits>
762_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
763operator!=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
764  if (__lhs.size() != __rhs.size())
765    return true;
766  return __lhs.compare(__rhs) != 0;
767}
768
769template <class _CharT, class _Traits, int = 1>
770_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
771operator!=(basic_string_view<_CharT, _Traits> __lhs,
772           __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
773  if (__lhs.size() != __rhs.size())
774    return true;
775  return __lhs.compare(__rhs) != 0;
776}
777
778template <class _CharT, class _Traits, int = 2>
779_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
780operator!=(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
781           basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
782  if (__lhs.size() != __rhs.size())
783    return true;
784  return __lhs.compare(__rhs) != 0;
785}
786
787// operator <
788template <class _CharT, class _Traits>
789_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
790operator<(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
791  return __lhs.compare(__rhs) < 0;
792}
793
794template <class _CharT, class _Traits, int = 1>
795_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
796operator<(basic_string_view<_CharT, _Traits> __lhs,
797          __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
798  return __lhs.compare(__rhs) < 0;
799}
800
801template <class _CharT, class _Traits, int = 2>
802_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
803operator<(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
804          basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
805  return __lhs.compare(__rhs) < 0;
806}
807
808// operator >
809template <class _CharT, class _Traits>
810_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
811operator>(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
812  return __lhs.compare(__rhs) > 0;
813}
814
815template <class _CharT, class _Traits, int = 1>
816_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
817operator>(basic_string_view<_CharT, _Traits> __lhs,
818          __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
819  return __lhs.compare(__rhs) > 0;
820}
821
822template <class _CharT, class _Traits, int = 2>
823_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
824operator>(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
825          basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
826  return __lhs.compare(__rhs) > 0;
827}
828
829// operator <=
830template <class _CharT, class _Traits>
831_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
832operator<=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
833  return __lhs.compare(__rhs) <= 0;
834}
835
836template <class _CharT, class _Traits, int = 1>
837_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
838operator<=(basic_string_view<_CharT, _Traits> __lhs,
839           __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
840  return __lhs.compare(__rhs) <= 0;
841}
842
843template <class _CharT, class _Traits, int = 2>
844_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
845operator<=(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
846           basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
847  return __lhs.compare(__rhs) <= 0;
848}
849
850// operator >=
851template <class _CharT, class _Traits>
852_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
853operator>=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
854  return __lhs.compare(__rhs) >= 0;
855}
856
857template <class _CharT, class _Traits, int = 1>
858_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
859operator>=(basic_string_view<_CharT, _Traits> __lhs,
860           __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
861  return __lhs.compare(__rhs) >= 0;
862}
863
864template <class _CharT, class _Traits, int = 2>
865_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
866operator>=(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
867           basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
868  return __lhs.compare(__rhs) >= 0;
869}
870
871#endif //  _LIBCPP_STD_VER >= 20
872
873template <class _CharT, class _Traits>
874_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
875operator<<(basic_ostream<_CharT, _Traits>& __os, basic_string_view<_CharT, _Traits> __str);
876
877// [string.view.hash]
878template <class _CharT>
879struct __string_view_hash : public __unary_function<basic_string_view<_CharT, char_traits<_CharT> >, size_t> {
880  _LIBCPP_HIDE_FROM_ABI size_t operator()(const basic_string_view<_CharT, char_traits<_CharT> > __val) const _NOEXCEPT {
881    return std::__do_string_hash(__val.data(), __val.data() + __val.size());
882  }
883};
884
885template <>
886struct hash<basic_string_view<char, char_traits<char> > > : __string_view_hash<char> {};
887
888#ifndef _LIBCPP_HAS_NO_CHAR8_T
889template <>
890struct hash<basic_string_view<char8_t, char_traits<char8_t> > > : __string_view_hash<char8_t> {};
891#endif
892
893template <>
894struct hash<basic_string_view<char16_t, char_traits<char16_t> > > : __string_view_hash<char16_t> {};
895
896template <>
897struct hash<basic_string_view<char32_t, char_traits<char32_t> > > : __string_view_hash<char32_t> {};
898
899#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
900template <>
901struct hash<basic_string_view<wchar_t, char_traits<wchar_t> > > : __string_view_hash<wchar_t> {};
902#endif
903
904#if _LIBCPP_STD_VER >= 14
905inline namespace literals {
906inline namespace string_view_literals {
907inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR basic_string_view<char>
908operator""sv(const char* __str, size_t __len) _NOEXCEPT {
909  return basic_string_view<char>(__str, __len);
910}
911
912#  ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
913inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR basic_string_view<wchar_t>
914operator""sv(const wchar_t* __str, size_t __len) _NOEXCEPT {
915  return basic_string_view<wchar_t>(__str, __len);
916}
917#  endif
918
919#  ifndef _LIBCPP_HAS_NO_CHAR8_T
920inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR basic_string_view<char8_t>
921operator""sv(const char8_t* __str, size_t __len) _NOEXCEPT {
922  return basic_string_view<char8_t>(__str, __len);
923}
924#  endif
925
926inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR basic_string_view<char16_t>
927operator""sv(const char16_t* __str, size_t __len) _NOEXCEPT {
928  return basic_string_view<char16_t>(__str, __len);
929}
930
931inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR basic_string_view<char32_t>
932operator""sv(const char32_t* __str, size_t __len) _NOEXCEPT {
933  return basic_string_view<char32_t>(__str, __len);
934}
935} // namespace string_view_literals
936} // namespace literals
937#endif
938_LIBCPP_END_NAMESPACE_STD
939
940_LIBCPP_POP_MACROS
941
942#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
943#  include <algorithm>
944#  include <concepts>
945#  include <cstdlib>
946#  include <iterator>
947#  include <type_traits>
948#endif
949
950#endif // _LIBCPP_STRING_VIEW
951