xref: /freebsd/contrib/llvm-project/libcxx/include/string_view (revision 3a56015a2f5d630910177fa79a522bb95511ccf7)
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/ostream.h>
214#include <__fwd/string_view.h>
215#include <__iterator/bounded_iter.h>
216#include <__iterator/concepts.h>
217#include <__iterator/iterator_traits.h>
218#include <__iterator/reverse_iterator.h>
219#include <__iterator/wrap_iter.h>
220#include <__memory/pointer_traits.h>
221#include <__ranges/concepts.h>
222#include <__ranges/data.h>
223#include <__ranges/enable_borrowed_range.h>
224#include <__ranges/enable_view.h>
225#include <__ranges/size.h>
226#include <__string/char_traits.h>
227#include <__type_traits/is_array.h>
228#include <__type_traits/is_convertible.h>
229#include <__type_traits/is_same.h>
230#include <__type_traits/is_standard_layout.h>
231#include <__type_traits/is_trivial.h>
232#include <__type_traits/remove_cvref.h>
233#include <__type_traits/remove_reference.h>
234#include <__type_traits/type_identity.h>
235#include <cstddef>
236#include <iosfwd>
237#include <limits>
238#include <stdexcept>
239#include <version>
240
241// standard-mandated includes
242
243// [iterator.range]
244#include <__iterator/access.h>
245#include <__iterator/data.h>
246#include <__iterator/empty.h>
247#include <__iterator/reverse_access.h>
248#include <__iterator/size.h>
249
250// [string.view.synop]
251#include <compare>
252
253#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
254#  pragma GCC system_header
255#endif
256
257_LIBCPP_PUSH_MACROS
258#include <__undef_macros>
259
260_LIBCPP_BEGIN_NAMESPACE_STD
261
262// TODO: This is a workaround for some vendors to carry a downstream diff to accept `nullptr` in
263//       string_view constructors. This can be refactored when this exact form isn't needed anymore.
264template <class _Traits>
265_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR inline size_t
266__char_traits_length_checked(const typename _Traits::char_type* __s) _NOEXCEPT {
267  // This needs to be a single statement for C++11 constexpr
268  return _LIBCPP_ASSERT_NON_NULL(
269             __s != nullptr, "null pointer passed to non-null argument of char_traits<...>::length"),
270         _Traits::length(__s);
271}
272
273template <class _CharT, class _Traits>
274class basic_string_view {
275public:
276  // types
277  using traits_type     = _Traits;
278  using value_type      = _CharT;
279  using pointer         = _CharT*;
280  using const_pointer   = const _CharT*;
281  using reference       = _CharT&;
282  using const_reference = const _CharT&;
283#if defined(_LIBCPP_ABI_BOUNDED_ITERATORS)
284  using const_iterator = __bounded_iter<const_pointer>;
285#elif defined(_LIBCPP_ABI_USE_WRAP_ITER_IN_STD_STRING_VIEW)
286  using const_iterator = __wrap_iter<const_pointer>;
287#else
288  using const_iterator = const_pointer;
289#endif
290  using iterator                                = const_iterator;
291  using const_reverse_iterator                  = std::reverse_iterator<const_iterator>;
292  using reverse_iterator                        = const_reverse_iterator;
293  using size_type                               = size_t;
294  using difference_type                         = ptrdiff_t;
295  static _LIBCPP_CONSTEXPR const size_type npos = -1; // size_type(-1);
296
297  static_assert(!is_array<value_type>::value, "Character type of basic_string_view must not be an array");
298  static_assert(is_standard_layout<value_type>::value, "Character type of basic_string_view must be standard-layout");
299  static_assert(is_trivial<value_type>::value, "Character type of basic_string_view must be trivial");
300  static_assert(is_same<_CharT, typename traits_type::char_type>::value,
301                "traits_type::char_type must be the same type as CharT");
302
303  // [string.view.cons], construct/copy
304  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI basic_string_view() _NOEXCEPT : __data_(nullptr), __size_(0) {}
305
306  _LIBCPP_HIDE_FROM_ABI basic_string_view(const basic_string_view&) _NOEXCEPT = default;
307
308  _LIBCPP_HIDE_FROM_ABI basic_string_view& operator=(const basic_string_view&) _NOEXCEPT = default;
309
310  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI basic_string_view(const _CharT* __s, size_type __len) _NOEXCEPT
311      : __data_(__s),
312        __size_(__len) {
313#if _LIBCPP_STD_VER >= 14
314    // Allocations must fit in `ptrdiff_t` for pointer arithmetic to work. If `__len` exceeds it, the input
315    // range could not have been valid. Most likely the caller underflowed some arithmetic and inadvertently
316    // passed in a negative length.
317    _LIBCPP_ASSERT_VALID_INPUT_RANGE(
318        __len <= static_cast<size_type>(numeric_limits<difference_type>::max()),
319        "string_view::string_view(_CharT *, size_t): length does not fit in difference_type");
320    _LIBCPP_ASSERT_NON_NULL(
321        __len == 0 || __s != nullptr, "string_view::string_view(_CharT *, size_t): received nullptr");
322#endif
323  }
324
325#if _LIBCPP_STD_VER >= 20
326  template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
327    requires(is_same_v<iter_value_t<_It>, _CharT> && !is_convertible_v<_End, size_type>)
328  constexpr _LIBCPP_HIDE_FROM_ABI basic_string_view(_It __begin, _End __end)
329      : __data_(std::to_address(__begin)), __size_(__end - __begin) {
330    _LIBCPP_ASSERT_VALID_INPUT_RANGE(
331        (__end - __begin) >= 0, "std::string_view::string_view(iterator, sentinel) received invalid range");
332  }
333#endif // _LIBCPP_STD_VER >= 20
334
335#if _LIBCPP_STD_VER >= 23
336  template <class _Range>
337    requires(!is_same_v<remove_cvref_t<_Range>, basic_string_view> && ranges::contiguous_range<_Range> &&
338             ranges::sized_range<_Range> && is_same_v<ranges::range_value_t<_Range>, _CharT> &&
339             !is_convertible_v<_Range, const _CharT*> &&
340             (!requires(remove_cvref_t<_Range>& __d) { __d.operator std::basic_string_view<_CharT, _Traits>(); }))
341  constexpr explicit _LIBCPP_HIDE_FROM_ABI basic_string_view(_Range&& __r)
342      : __data_(ranges::data(__r)), __size_(ranges::size(__r)) {}
343#endif // _LIBCPP_STD_VER >= 23
344
345  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI basic_string_view(const _CharT* __s)
346      : __data_(__s), __size_(std::__char_traits_length_checked<_Traits>(__s)) {}
347
348#if _LIBCPP_STD_VER >= 23
349  basic_string_view(nullptr_t) = delete;
350#endif
351
352  // [string.view.iterators], iterators
353  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return cbegin(); }
354
355  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return cend(); }
356
357  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT {
358#ifdef _LIBCPP_ABI_BOUNDED_ITERATORS
359    return std::__make_bounded_iter(data(), data(), data() + size());
360#else
361    return const_iterator(__data_);
362#endif
363  }
364
365  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT {
366#ifdef _LIBCPP_ABI_BOUNDED_ITERATORS
367    return std::__make_bounded_iter(data() + size(), data(), data() + size());
368#else
369    return const_iterator(__data_ + __size_);
370#endif
371  }
372
373  _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rbegin() const _NOEXCEPT {
374    return const_reverse_iterator(cend());
375  }
376
377  _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rend() const _NOEXCEPT {
378    return const_reverse_iterator(cbegin());
379  }
380
381  _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crbegin() const _NOEXCEPT {
382    return const_reverse_iterator(cend());
383  }
384
385  _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crend() const _NOEXCEPT {
386    return const_reverse_iterator(cbegin());
387  }
388
389  // [string.view.capacity], capacity
390  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __size_; }
391
392  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI size_type length() const _NOEXCEPT { return __size_; }
393
394  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT {
395    return numeric_limits<size_type>::max() / sizeof(value_type);
396  }
397
398  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR bool empty() const _NOEXCEPT { return __size_ == 0; }
399
400  // [string.view.access], element access
401  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_reference operator[](size_type __pos) const _NOEXCEPT {
402    return _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__pos < size(), "string_view[] index out of bounds"), __data_[__pos];
403  }
404
405  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_reference at(size_type __pos) const {
406    return __pos >= size() ? (__throw_out_of_range("string_view::at"), __data_[0]) : __data_[__pos];
407  }
408
409  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_reference front() const _NOEXCEPT {
410    return _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string_view::front(): string is empty"), __data_[0];
411  }
412
413  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_reference back() const _NOEXCEPT {
414    return _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string_view::back(): string is empty"), __data_[__size_ - 1];
415  }
416
417  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI const_pointer data() const _NOEXCEPT { return __data_; }
418
419  // [string.view.modifiers], modifiers:
420  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI void remove_prefix(size_type __n) _NOEXCEPT {
421    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__n <= size(), "remove_prefix() can't remove more than size()");
422    __data_ += __n;
423    __size_ -= __n;
424  }
425
426  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI void remove_suffix(size_type __n) _NOEXCEPT {
427    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__n <= size(), "remove_suffix() can't remove more than size()");
428    __size_ -= __n;
429  }
430
431  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI void swap(basic_string_view& __other) _NOEXCEPT {
432    const value_type* __p = __data_;
433    __data_               = __other.__data_;
434    __other.__data_       = __p;
435
436    size_type __sz  = __size_;
437    __size_         = __other.__size_;
438    __other.__size_ = __sz;
439  }
440
441  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
442  copy(_CharT* __s, size_type __n, size_type __pos = 0) const {
443    if (__pos > size())
444      __throw_out_of_range("string_view::copy");
445    size_type __rlen = std::min(__n, size() - __pos);
446    _Traits::copy(__s, data() + __pos, __rlen);
447    return __rlen;
448  }
449
450  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI basic_string_view substr(size_type __pos = 0, size_type __n = npos) const {
451    return __pos > size() ? (__throw_out_of_range("string_view::substr"), basic_string_view())
452                          : basic_string_view(data() + __pos, std::min(__n, size() - __pos));
453  }
454
455  _LIBCPP_CONSTEXPR_SINCE_CXX14 int compare(basic_string_view __sv) const _NOEXCEPT {
456    size_type __rlen = std::min(size(), __sv.size());
457    int __retval     = _Traits::compare(data(), __sv.data(), __rlen);
458    if (__retval == 0) // first __rlen chars matched
459      __retval = size() == __sv.size() ? 0 : (size() < __sv.size() ? -1 : 1);
460    return __retval;
461  }
462
463  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int
464  compare(size_type __pos1, size_type __n1, basic_string_view __sv) const {
465    return substr(__pos1, __n1).compare(__sv);
466  }
467
468  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int
469  compare(size_type __pos1, size_type __n1, basic_string_view __sv, size_type __pos2, size_type __n2) const {
470    return substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
471  }
472
473  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int compare(const _CharT* __s) const _NOEXCEPT {
474    return compare(basic_string_view(__s));
475  }
476
477  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int
478  compare(size_type __pos1, size_type __n1, const _CharT* __s) const {
479    return substr(__pos1, __n1).compare(basic_string_view(__s));
480  }
481
482  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int
483  compare(size_type __pos1, size_type __n1, const _CharT* __s, size_type __n2) const {
484    return substr(__pos1, __n1).compare(basic_string_view(__s, __n2));
485  }
486
487  // find
488  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
489  find(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT {
490    _LIBCPP_ASSERT_NON_NULL(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
491    return std::__str_find<value_type, size_type, traits_type, npos>(data(), size(), __s.data(), __pos, __s.size());
492  }
493
494  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type find(_CharT __c, size_type __pos = 0) const _NOEXCEPT {
495    return std::__str_find<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
496  }
497
498  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
499  find(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
500    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find(): received nullptr");
501    return std::__str_find<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
502  }
503
504  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
505  find(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT {
506    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find(): received nullptr");
507    return std::__str_find<value_type, size_type, traits_type, npos>(
508        data(), size(), __s, __pos, traits_type::length(__s));
509  }
510
511  // rfind
512  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
513  rfind(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT {
514    _LIBCPP_ASSERT_NON_NULL(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
515    return std::__str_rfind<value_type, size_type, traits_type, npos>(data(), size(), __s.data(), __pos, __s.size());
516  }
517
518  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
519  rfind(_CharT __c, size_type __pos = npos) const _NOEXCEPT {
520    return std::__str_rfind<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
521  }
522
523  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
524  rfind(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
525    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::rfind(): received nullptr");
526    return std::__str_rfind<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
527  }
528
529  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
530  rfind(const _CharT* __s, size_type __pos = npos) const _NOEXCEPT {
531    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::rfind(): received nullptr");
532    return std::__str_rfind<value_type, size_type, traits_type, npos>(
533        data(), size(), __s, __pos, traits_type::length(__s));
534  }
535
536  // find_first_of
537  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
538  find_first_of(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT {
539    _LIBCPP_ASSERT_NON_NULL(__s.size() == 0 || __s.data() != nullptr, "string_view::find_first_of(): received nullptr");
540    return std::__str_find_first_of<value_type, size_type, traits_type, npos>(
541        data(), size(), __s.data(), __pos, __s.size());
542  }
543
544  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
545  find_first_of(_CharT __c, size_type __pos = 0) const _NOEXCEPT {
546    return find(__c, __pos);
547  }
548
549  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
550  find_first_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
551    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find_first_of(): received nullptr");
552    return std::__str_find_first_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
553  }
554
555  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
556  find_first_of(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT {
557    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find_first_of(): received nullptr");
558    return std::__str_find_first_of<value_type, size_type, traits_type, npos>(
559        data(), size(), __s, __pos, traits_type::length(__s));
560  }
561
562  // find_last_of
563  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
564  find_last_of(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT {
565    _LIBCPP_ASSERT_NON_NULL(__s.size() == 0 || __s.data() != nullptr, "string_view::find_last_of(): received nullptr");
566    return std::__str_find_last_of<value_type, size_type, traits_type, npos>(
567        data(), size(), __s.data(), __pos, __s.size());
568  }
569
570  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
571  find_last_of(_CharT __c, size_type __pos = npos) const _NOEXCEPT {
572    return rfind(__c, __pos);
573  }
574
575  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
576  find_last_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
577    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find_last_of(): received nullptr");
578    return std::__str_find_last_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
579  }
580
581  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
582  find_last_of(const _CharT* __s, size_type __pos = npos) const _NOEXCEPT {
583    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find_last_of(): received nullptr");
584    return std::__str_find_last_of<value_type, size_type, traits_type, npos>(
585        data(), size(), __s, __pos, traits_type::length(__s));
586  }
587
588  // find_first_not_of
589  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
590  find_first_not_of(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT {
591    _LIBCPP_ASSERT_NON_NULL(
592        __s.size() == 0 || __s.data() != nullptr, "string_view::find_first_not_of(): received nullptr");
593    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(
594        data(), size(), __s.data(), __pos, __s.size());
595  }
596
597  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
598  find_first_not_of(_CharT __c, size_type __pos = 0) const _NOEXCEPT {
599    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
600  }
601
602  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
603  find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
604    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find_first_not_of(): received nullptr");
605    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
606  }
607
608  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
609  find_first_not_of(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT {
610    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find_first_not_of(): received nullptr");
611    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(
612        data(), size(), __s, __pos, traits_type::length(__s));
613  }
614
615  // find_last_not_of
616  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
617  find_last_not_of(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT {
618    _LIBCPP_ASSERT_NON_NULL(
619        __s.size() == 0 || __s.data() != nullptr, "string_view::find_last_not_of(): received nullptr");
620    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(
621        data(), size(), __s.data(), __pos, __s.size());
622  }
623
624  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
625  find_last_not_of(_CharT __c, size_type __pos = npos) const _NOEXCEPT {
626    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
627  }
628
629  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
630  find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
631    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find_last_not_of(): received nullptr");
632    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
633  }
634
635  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
636  find_last_not_of(const _CharT* __s, size_type __pos = npos) const _NOEXCEPT {
637    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find_last_not_of(): received nullptr");
638    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(
639        data(), size(), __s, __pos, traits_type::length(__s));
640  }
641
642#if _LIBCPP_STD_VER >= 20
643  constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(basic_string_view __s) const noexcept {
644    return size() >= __s.size() && compare(0, __s.size(), __s) == 0;
645  }
646
647  constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(value_type __c) const noexcept {
648    return !empty() && _Traits::eq(front(), __c);
649  }
650
651  constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(const value_type* __s) const noexcept {
652    return starts_with(basic_string_view(__s));
653  }
654
655  constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(basic_string_view __s) const noexcept {
656    return size() >= __s.size() && compare(size() - __s.size(), npos, __s) == 0;
657  }
658
659  constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(value_type __c) const noexcept {
660    return !empty() && _Traits::eq(back(), __c);
661  }
662
663  constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(const value_type* __s) const noexcept {
664    return ends_with(basic_string_view(__s));
665  }
666#endif
667
668#if _LIBCPP_STD_VER >= 23
669  constexpr _LIBCPP_HIDE_FROM_ABI bool contains(basic_string_view __sv) const noexcept { return find(__sv) != npos; }
670
671  constexpr _LIBCPP_HIDE_FROM_ABI bool contains(value_type __c) const noexcept { return find(__c) != npos; }
672
673  constexpr _LIBCPP_HIDE_FROM_ABI bool contains(const value_type* __s) const { return find(__s) != npos; }
674#endif
675
676private:
677  const value_type* __data_;
678  size_type __size_;
679};
680_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(basic_string_view);
681
682#if _LIBCPP_STD_VER >= 20
683template <class _CharT, class _Traits>
684inline constexpr bool ranges::enable_view<basic_string_view<_CharT, _Traits>> = true;
685
686template <class _CharT, class _Traits>
687inline constexpr bool ranges::enable_borrowed_range<basic_string_view<_CharT, _Traits> > = true;
688#endif // _LIBCPP_STD_VER >= 20
689
690// [string.view.deduct]
691
692#if _LIBCPP_STD_VER >= 20
693template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
694basic_string_view(_It, _End) -> basic_string_view<iter_value_t<_It>>;
695#endif // _LIBCPP_STD_VER >= 20
696
697#if _LIBCPP_STD_VER >= 23
698template <ranges::contiguous_range _Range>
699basic_string_view(_Range) -> basic_string_view<ranges::range_value_t<_Range>>;
700#endif
701
702// [string.view.comparison]
703
704#if _LIBCPP_STD_VER >= 20
705
706template <class _CharT, class _Traits>
707_LIBCPP_HIDE_FROM_ABI constexpr bool operator==(basic_string_view<_CharT, _Traits> __lhs,
708                                                type_identity_t<basic_string_view<_CharT, _Traits>> __rhs) noexcept {
709  if (__lhs.size() != __rhs.size())
710    return false;
711  return __lhs.compare(__rhs) == 0;
712}
713
714template <class _CharT, class _Traits>
715_LIBCPP_HIDE_FROM_ABI constexpr auto operator<=>(basic_string_view<_CharT, _Traits> __lhs,
716                                                 type_identity_t<basic_string_view<_CharT, _Traits>> __rhs) noexcept {
717  if constexpr (requires { typename _Traits::comparison_category; }) {
718    // [string.view]/4
719    static_assert(
720        __comparison_category<typename _Traits::comparison_category>, "return type is not a comparison category type");
721    return static_cast<typename _Traits::comparison_category>(__lhs.compare(__rhs) <=> 0);
722  } else {
723    return static_cast<weak_ordering>(__lhs.compare(__rhs) <=> 0);
724  }
725}
726
727#else
728
729// operator ==
730
731template <class _CharT, class _Traits>
732_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
733operator==(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
734  if (__lhs.size() != __rhs.size())
735    return false;
736  return __lhs.compare(__rhs) == 0;
737}
738
739// The dummy default template parameters are used to work around a MSVC issue with mangling, see VSO-409326 for details.
740// This applies to the other sufficient overloads below for the other comparison operators.
741template <class _CharT, class _Traits, int = 1>
742_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
743operator==(basic_string_view<_CharT, _Traits> __lhs,
744           __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
745  if (__lhs.size() != __rhs.size())
746    return false;
747  return __lhs.compare(__rhs) == 0;
748}
749
750template <class _CharT, class _Traits, int = 2>
751_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
752operator==(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
753           basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
754  if (__lhs.size() != __rhs.size())
755    return false;
756  return __lhs.compare(__rhs) == 0;
757}
758
759// operator !=
760template <class _CharT, class _Traits>
761_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
762operator!=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
763  if (__lhs.size() != __rhs.size())
764    return true;
765  return __lhs.compare(__rhs) != 0;
766}
767
768template <class _CharT, class _Traits, int = 1>
769_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
770operator!=(basic_string_view<_CharT, _Traits> __lhs,
771           __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
772  if (__lhs.size() != __rhs.size())
773    return true;
774  return __lhs.compare(__rhs) != 0;
775}
776
777template <class _CharT, class _Traits, int = 2>
778_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
779operator!=(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
780           basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
781  if (__lhs.size() != __rhs.size())
782    return true;
783  return __lhs.compare(__rhs) != 0;
784}
785
786// operator <
787template <class _CharT, class _Traits>
788_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
789operator<(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
790  return __lhs.compare(__rhs) < 0;
791}
792
793template <class _CharT, class _Traits, int = 1>
794_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
795operator<(basic_string_view<_CharT, _Traits> __lhs,
796          __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
797  return __lhs.compare(__rhs) < 0;
798}
799
800template <class _CharT, class _Traits, int = 2>
801_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
802operator<(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
803          basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
804  return __lhs.compare(__rhs) < 0;
805}
806
807// operator >
808template <class _CharT, class _Traits>
809_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
810operator>(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
811  return __lhs.compare(__rhs) > 0;
812}
813
814template <class _CharT, class _Traits, int = 1>
815_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
816operator>(basic_string_view<_CharT, _Traits> __lhs,
817          __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
818  return __lhs.compare(__rhs) > 0;
819}
820
821template <class _CharT, class _Traits, int = 2>
822_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
823operator>(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
824          basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
825  return __lhs.compare(__rhs) > 0;
826}
827
828// operator <=
829template <class _CharT, class _Traits>
830_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
831operator<=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
832  return __lhs.compare(__rhs) <= 0;
833}
834
835template <class _CharT, class _Traits, int = 1>
836_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
837operator<=(basic_string_view<_CharT, _Traits> __lhs,
838           __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
839  return __lhs.compare(__rhs) <= 0;
840}
841
842template <class _CharT, class _Traits, int = 2>
843_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
844operator<=(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
845           basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
846  return __lhs.compare(__rhs) <= 0;
847}
848
849// operator >=
850template <class _CharT, class _Traits>
851_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
852operator>=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
853  return __lhs.compare(__rhs) >= 0;
854}
855
856template <class _CharT, class _Traits, int = 1>
857_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
858operator>=(basic_string_view<_CharT, _Traits> __lhs,
859           __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
860  return __lhs.compare(__rhs) >= 0;
861}
862
863template <class _CharT, class _Traits, int = 2>
864_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
865operator>=(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
866           basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
867  return __lhs.compare(__rhs) >= 0;
868}
869
870#endif //  _LIBCPP_STD_VER >= 20
871
872template <class _CharT, class _Traits>
873_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
874operator<<(basic_ostream<_CharT, _Traits>& __os, basic_string_view<_CharT, _Traits> __str);
875
876// [string.view.hash]
877template <class _CharT>
878struct __string_view_hash : public __unary_function<basic_string_view<_CharT, char_traits<_CharT> >, size_t> {
879  _LIBCPP_HIDE_FROM_ABI size_t operator()(const basic_string_view<_CharT, char_traits<_CharT> > __val) const _NOEXCEPT {
880    return std::__do_string_hash(__val.data(), __val.data() + __val.size());
881  }
882};
883
884template <>
885struct hash<basic_string_view<char, char_traits<char> > > : __string_view_hash<char> {};
886
887#ifndef _LIBCPP_HAS_NO_CHAR8_T
888template <>
889struct hash<basic_string_view<char8_t, char_traits<char8_t> > > : __string_view_hash<char8_t> {};
890#endif
891
892template <>
893struct hash<basic_string_view<char16_t, char_traits<char16_t> > > : __string_view_hash<char16_t> {};
894
895template <>
896struct hash<basic_string_view<char32_t, char_traits<char32_t> > > : __string_view_hash<char32_t> {};
897
898#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
899template <>
900struct hash<basic_string_view<wchar_t, char_traits<wchar_t> > > : __string_view_hash<wchar_t> {};
901#endif
902
903#if _LIBCPP_STD_VER >= 14
904inline namespace literals {
905inline namespace string_view_literals {
906inline _LIBCPP_HIDE_FROM_ABI constexpr basic_string_view<char> operator""sv(const char* __str, size_t __len) noexcept {
907  return basic_string_view<char>(__str, __len);
908}
909
910#  ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
911inline _LIBCPP_HIDE_FROM_ABI constexpr basic_string_view<wchar_t>
912operator""sv(const wchar_t* __str, size_t __len) noexcept {
913  return basic_string_view<wchar_t>(__str, __len);
914}
915#  endif
916
917#  ifndef _LIBCPP_HAS_NO_CHAR8_T
918inline _LIBCPP_HIDE_FROM_ABI constexpr basic_string_view<char8_t>
919operator""sv(const char8_t* __str, size_t __len) noexcept {
920  return basic_string_view<char8_t>(__str, __len);
921}
922#  endif
923
924inline _LIBCPP_HIDE_FROM_ABI constexpr basic_string_view<char16_t>
925operator""sv(const char16_t* __str, size_t __len) noexcept {
926  return basic_string_view<char16_t>(__str, __len);
927}
928
929inline _LIBCPP_HIDE_FROM_ABI constexpr basic_string_view<char32_t>
930operator""sv(const char32_t* __str, size_t __len) noexcept {
931  return basic_string_view<char32_t>(__str, __len);
932}
933} // namespace string_view_literals
934} // namespace literals
935#endif
936_LIBCPP_END_NAMESPACE_STD
937
938_LIBCPP_POP_MACROS
939
940#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
941#  include <algorithm>
942#  include <concepts>
943#  include <cstdlib>
944#  include <iterator>
945#  include <type_traits>
946#endif
947
948#endif // _LIBCPP_STRING_VIEW
949