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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    // Use the `__assume_valid` form of the constructor to avoid an unnecessary check. Any substring of a view is a
452    // valid view. In particular, `size()` is known to be smaller than `numeric_limits<difference_type>::max()`, so the
453    // new size is also smaller. See also https://github.com/llvm/llvm-project/issues/91634.
454    return __pos > size() ? (__throw_out_of_range("string_view::substr"), basic_string_view())
455                          : basic_string_view(__assume_valid(), data() + __pos, std::min(__n, size() - __pos));
456  }
457
458  _LIBCPP_CONSTEXPR_SINCE_CXX14 int compare(basic_string_view __sv) const _NOEXCEPT {
459    size_type __rlen = std::min(size(), __sv.size());
460    int __retval     = _Traits::compare(data(), __sv.data(), __rlen);
461    if (__retval == 0) // first __rlen chars matched
462      __retval = size() == __sv.size() ? 0 : (size() < __sv.size() ? -1 : 1);
463    return __retval;
464  }
465
466  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int
467  compare(size_type __pos1, size_type __n1, basic_string_view __sv) const {
468    return substr(__pos1, __n1).compare(__sv);
469  }
470
471  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int
472  compare(size_type __pos1, size_type __n1, basic_string_view __sv, size_type __pos2, size_type __n2) const {
473    return substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
474  }
475
476  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int compare(const _CharT* __s) const _NOEXCEPT {
477    return compare(basic_string_view(__s));
478  }
479
480  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int
481  compare(size_type __pos1, size_type __n1, const _CharT* __s) const {
482    return substr(__pos1, __n1).compare(basic_string_view(__s));
483  }
484
485  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI int
486  compare(size_type __pos1, size_type __n1, const _CharT* __s, size_type __n2) const {
487    return substr(__pos1, __n1).compare(basic_string_view(__s, __n2));
488  }
489
490  // find
491  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
492  find(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT {
493    _LIBCPP_ASSERT_NON_NULL(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
494    return std::__str_find<value_type, size_type, traits_type, npos>(data(), size(), __s.data(), __pos, __s.size());
495  }
496
497  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type find(_CharT __c, size_type __pos = 0) const _NOEXCEPT {
498    return std::__str_find<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
499  }
500
501  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
502  find(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
503    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find(): received nullptr");
504    return std::__str_find<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
505  }
506
507  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
508  find(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT {
509    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find(): received nullptr");
510    return std::__str_find<value_type, size_type, traits_type, npos>(
511        data(), size(), __s, __pos, traits_type::length(__s));
512  }
513
514  // rfind
515  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
516  rfind(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT {
517    _LIBCPP_ASSERT_NON_NULL(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
518    return std::__str_rfind<value_type, size_type, traits_type, npos>(data(), size(), __s.data(), __pos, __s.size());
519  }
520
521  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
522  rfind(_CharT __c, size_type __pos = npos) const _NOEXCEPT {
523    return std::__str_rfind<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
524  }
525
526  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
527  rfind(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
528    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::rfind(): received nullptr");
529    return std::__str_rfind<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
530  }
531
532  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
533  rfind(const _CharT* __s, size_type __pos = npos) const _NOEXCEPT {
534    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::rfind(): received nullptr");
535    return std::__str_rfind<value_type, size_type, traits_type, npos>(
536        data(), size(), __s, __pos, traits_type::length(__s));
537  }
538
539  // find_first_of
540  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
541  find_first_of(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT {
542    _LIBCPP_ASSERT_NON_NULL(__s.size() == 0 || __s.data() != nullptr, "string_view::find_first_of(): received nullptr");
543    return std::__str_find_first_of<value_type, size_type, traits_type, npos>(
544        data(), size(), __s.data(), __pos, __s.size());
545  }
546
547  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
548  find_first_of(_CharT __c, size_type __pos = 0) const _NOEXCEPT {
549    return find(__c, __pos);
550  }
551
552  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
553  find_first_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
554    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find_first_of(): received nullptr");
555    return std::__str_find_first_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
556  }
557
558  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
559  find_first_of(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT {
560    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find_first_of(): received nullptr");
561    return std::__str_find_first_of<value_type, size_type, traits_type, npos>(
562        data(), size(), __s, __pos, traits_type::length(__s));
563  }
564
565  // find_last_of
566  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
567  find_last_of(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT {
568    _LIBCPP_ASSERT_NON_NULL(__s.size() == 0 || __s.data() != nullptr, "string_view::find_last_of(): received nullptr");
569    return std::__str_find_last_of<value_type, size_type, traits_type, npos>(
570        data(), size(), __s.data(), __pos, __s.size());
571  }
572
573  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
574  find_last_of(_CharT __c, size_type __pos = npos) const _NOEXCEPT {
575    return rfind(__c, __pos);
576  }
577
578  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
579  find_last_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
580    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find_last_of(): received nullptr");
581    return std::__str_find_last_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
582  }
583
584  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
585  find_last_of(const _CharT* __s, size_type __pos = npos) const _NOEXCEPT {
586    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find_last_of(): received nullptr");
587    return std::__str_find_last_of<value_type, size_type, traits_type, npos>(
588        data(), size(), __s, __pos, traits_type::length(__s));
589  }
590
591  // find_first_not_of
592  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
593  find_first_not_of(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT {
594    _LIBCPP_ASSERT_NON_NULL(
595        __s.size() == 0 || __s.data() != nullptr, "string_view::find_first_not_of(): received nullptr");
596    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(
597        data(), size(), __s.data(), __pos, __s.size());
598  }
599
600  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
601  find_first_not_of(_CharT __c, size_type __pos = 0) const _NOEXCEPT {
602    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
603  }
604
605  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
606  find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
607    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find_first_not_of(): received nullptr");
608    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
609  }
610
611  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
612  find_first_not_of(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT {
613    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find_first_not_of(): received nullptr");
614    return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(
615        data(), size(), __s, __pos, traits_type::length(__s));
616  }
617
618  // find_last_not_of
619  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
620  find_last_not_of(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT {
621    _LIBCPP_ASSERT_NON_NULL(
622        __s.size() == 0 || __s.data() != nullptr, "string_view::find_last_not_of(): received nullptr");
623    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(
624        data(), size(), __s.data(), __pos, __s.size());
625  }
626
627  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
628  find_last_not_of(_CharT __c, size_type __pos = npos) const _NOEXCEPT {
629    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
630  }
631
632  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
633  find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT {
634    _LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string_view::find_last_not_of(): received nullptr");
635    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
636  }
637
638  _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI size_type
639  find_last_not_of(const _CharT* __s, size_type __pos = npos) const _NOEXCEPT {
640    _LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string_view::find_last_not_of(): received nullptr");
641    return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(
642        data(), size(), __s, __pos, traits_type::length(__s));
643  }
644
645#if _LIBCPP_STD_VER >= 20
646  constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(basic_string_view __s) const noexcept {
647    return size() >= __s.size() && compare(0, __s.size(), __s) == 0;
648  }
649
650  constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(value_type __c) const noexcept {
651    return !empty() && _Traits::eq(front(), __c);
652  }
653
654  constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(const value_type* __s) const noexcept {
655    return starts_with(basic_string_view(__s));
656  }
657
658  constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(basic_string_view __s) const noexcept {
659    return size() >= __s.size() && compare(size() - __s.size(), npos, __s) == 0;
660  }
661
662  constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(value_type __c) const noexcept {
663    return !empty() && _Traits::eq(back(), __c);
664  }
665
666  constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(const value_type* __s) const noexcept {
667    return ends_with(basic_string_view(__s));
668  }
669#endif
670
671#if _LIBCPP_STD_VER >= 23
672  constexpr _LIBCPP_HIDE_FROM_ABI bool contains(basic_string_view __sv) const noexcept { return find(__sv) != npos; }
673
674  constexpr _LIBCPP_HIDE_FROM_ABI bool contains(value_type __c) const noexcept { return find(__c) != npos; }
675
676  constexpr _LIBCPP_HIDE_FROM_ABI bool contains(const value_type* __s) const { return find(__s) != npos; }
677#endif
678
679private:
680  struct __assume_valid {};
681
682  // This is the same as the pointer and length constructor, but without the additional hardening checks. It is intended
683  // for use within the class, when the class invariants already guarantee the resulting object is valid. The compiler
684  // usually cannot eliminate the redundant checks because it does not know class invariants.
685  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI
686  basic_string_view(__assume_valid, const _CharT* __s, size_type __len) _NOEXCEPT
687      : __data_(__s),
688        __size_(__len) {}
689
690  const value_type* __data_;
691  size_type __size_;
692};
693_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(basic_string_view);
694
695#if _LIBCPP_STD_VER >= 20
696template <class _CharT, class _Traits>
697inline constexpr bool ranges::enable_view<basic_string_view<_CharT, _Traits>> = true;
698
699template <class _CharT, class _Traits>
700inline constexpr bool ranges::enable_borrowed_range<basic_string_view<_CharT, _Traits> > = true;
701#endif // _LIBCPP_STD_VER >= 20
702
703// [string.view.deduct]
704
705#if _LIBCPP_STD_VER >= 20
706template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
707basic_string_view(_It, _End) -> basic_string_view<iter_value_t<_It>>;
708#endif // _LIBCPP_STD_VER >= 20
709
710#if _LIBCPP_STD_VER >= 23
711template <ranges::contiguous_range _Range>
712basic_string_view(_Range) -> basic_string_view<ranges::range_value_t<_Range>>;
713#endif
714
715// [string.view.comparison]
716
717#if _LIBCPP_STD_VER >= 20
718
719template <class _CharT, class _Traits>
720_LIBCPP_HIDE_FROM_ABI constexpr bool operator==(basic_string_view<_CharT, _Traits> __lhs,
721                                                type_identity_t<basic_string_view<_CharT, _Traits>> __rhs) noexcept {
722  if (__lhs.size() != __rhs.size())
723    return false;
724  return __lhs.compare(__rhs) == 0;
725}
726
727template <class _CharT, class _Traits>
728_LIBCPP_HIDE_FROM_ABI constexpr auto operator<=>(basic_string_view<_CharT, _Traits> __lhs,
729                                                 type_identity_t<basic_string_view<_CharT, _Traits>> __rhs) noexcept {
730  if constexpr (requires { typename _Traits::comparison_category; }) {
731    // [string.view]/4
732    static_assert(
733        __comparison_category<typename _Traits::comparison_category>, "return type is not a comparison category type");
734    return static_cast<typename _Traits::comparison_category>(__lhs.compare(__rhs) <=> 0);
735  } else {
736    return static_cast<weak_ordering>(__lhs.compare(__rhs) <=> 0);
737  }
738}
739
740#else
741
742// operator ==
743
744template <class _CharT, class _Traits>
745_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
746operator==(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
747  if (__lhs.size() != __rhs.size())
748    return false;
749  return __lhs.compare(__rhs) == 0;
750}
751
752// The dummy default template parameters are used to work around a MSVC issue with mangling, see VSO-409326 for details.
753// This applies to the other sufficient overloads below for the other comparison operators.
754template <class _CharT, class _Traits, int = 1>
755_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
756operator==(basic_string_view<_CharT, _Traits> __lhs,
757           __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
758  if (__lhs.size() != __rhs.size())
759    return false;
760  return __lhs.compare(__rhs) == 0;
761}
762
763template <class _CharT, class _Traits, int = 2>
764_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
765operator==(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
766           basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
767  if (__lhs.size() != __rhs.size())
768    return false;
769  return __lhs.compare(__rhs) == 0;
770}
771
772// operator !=
773template <class _CharT, class _Traits>
774_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
775operator!=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
776  if (__lhs.size() != __rhs.size())
777    return true;
778  return __lhs.compare(__rhs) != 0;
779}
780
781template <class _CharT, class _Traits, int = 1>
782_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
783operator!=(basic_string_view<_CharT, _Traits> __lhs,
784           __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
785  if (__lhs.size() != __rhs.size())
786    return true;
787  return __lhs.compare(__rhs) != 0;
788}
789
790template <class _CharT, class _Traits, int = 2>
791_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
792operator!=(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
793           basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
794  if (__lhs.size() != __rhs.size())
795    return true;
796  return __lhs.compare(__rhs) != 0;
797}
798
799// operator <
800template <class _CharT, class _Traits>
801_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
802operator<(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
803  return __lhs.compare(__rhs) < 0;
804}
805
806template <class _CharT, class _Traits, int = 1>
807_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
808operator<(basic_string_view<_CharT, _Traits> __lhs,
809          __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
810  return __lhs.compare(__rhs) < 0;
811}
812
813template <class _CharT, class _Traits, int = 2>
814_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
815operator<(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
816          basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
817  return __lhs.compare(__rhs) < 0;
818}
819
820// operator >
821template <class _CharT, class _Traits>
822_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
823operator>(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
824  return __lhs.compare(__rhs) > 0;
825}
826
827template <class _CharT, class _Traits, int = 1>
828_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
829operator>(basic_string_view<_CharT, _Traits> __lhs,
830          __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
831  return __lhs.compare(__rhs) > 0;
832}
833
834template <class _CharT, class _Traits, int = 2>
835_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
836operator>(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
837          basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
838  return __lhs.compare(__rhs) > 0;
839}
840
841// operator <=
842template <class _CharT, class _Traits>
843_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
844operator<=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
845  return __lhs.compare(__rhs) <= 0;
846}
847
848template <class _CharT, class _Traits, int = 1>
849_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
850operator<=(basic_string_view<_CharT, _Traits> __lhs,
851           __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
852  return __lhs.compare(__rhs) <= 0;
853}
854
855template <class _CharT, class _Traits, int = 2>
856_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
857operator<=(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
858           basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
859  return __lhs.compare(__rhs) <= 0;
860}
861
862// operator >=
863template <class _CharT, class _Traits>
864_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
865operator>=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
866  return __lhs.compare(__rhs) >= 0;
867}
868
869template <class _CharT, class _Traits, int = 1>
870_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
871operator>=(basic_string_view<_CharT, _Traits> __lhs,
872           __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT {
873  return __lhs.compare(__rhs) >= 0;
874}
875
876template <class _CharT, class _Traits, int = 2>
877_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI bool
878operator>=(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
879           basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT {
880  return __lhs.compare(__rhs) >= 0;
881}
882
883#endif //  _LIBCPP_STD_VER >= 20
884
885template <class _CharT, class _Traits>
886_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
887operator<<(basic_ostream<_CharT, _Traits>& __os, basic_string_view<_CharT, _Traits> __str);
888
889// [string.view.hash]
890template <class _CharT>
891struct __string_view_hash : public __unary_function<basic_string_view<_CharT, char_traits<_CharT> >, size_t> {
892  _LIBCPP_HIDE_FROM_ABI size_t operator()(const basic_string_view<_CharT, char_traits<_CharT> > __val) const _NOEXCEPT {
893    return std::__do_string_hash(__val.data(), __val.data() + __val.size());
894  }
895};
896
897template <>
898struct hash<basic_string_view<char, char_traits<char> > > : __string_view_hash<char> {};
899
900#ifndef _LIBCPP_HAS_NO_CHAR8_T
901template <>
902struct hash<basic_string_view<char8_t, char_traits<char8_t> > > : __string_view_hash<char8_t> {};
903#endif
904
905template <>
906struct hash<basic_string_view<char16_t, char_traits<char16_t> > > : __string_view_hash<char16_t> {};
907
908template <>
909struct hash<basic_string_view<char32_t, char_traits<char32_t> > > : __string_view_hash<char32_t> {};
910
911#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
912template <>
913struct hash<basic_string_view<wchar_t, char_traits<wchar_t> > > : __string_view_hash<wchar_t> {};
914#endif
915
916#if _LIBCPP_STD_VER >= 14
917inline namespace literals {
918inline namespace string_view_literals {
919inline _LIBCPP_HIDE_FROM_ABI constexpr basic_string_view<char> operator""sv(const char* __str, size_t __len) noexcept {
920  return basic_string_view<char>(__str, __len);
921}
922
923#  ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
924inline _LIBCPP_HIDE_FROM_ABI constexpr basic_string_view<wchar_t>
925operator""sv(const wchar_t* __str, size_t __len) noexcept {
926  return basic_string_view<wchar_t>(__str, __len);
927}
928#  endif
929
930#  ifndef _LIBCPP_HAS_NO_CHAR8_T
931inline _LIBCPP_HIDE_FROM_ABI constexpr basic_string_view<char8_t>
932operator""sv(const char8_t* __str, size_t __len) noexcept {
933  return basic_string_view<char8_t>(__str, __len);
934}
935#  endif
936
937inline _LIBCPP_HIDE_FROM_ABI constexpr basic_string_view<char16_t>
938operator""sv(const char16_t* __str, size_t __len) noexcept {
939  return basic_string_view<char16_t>(__str, __len);
940}
941
942inline _LIBCPP_HIDE_FROM_ABI constexpr basic_string_view<char32_t>
943operator""sv(const char32_t* __str, size_t __len) noexcept {
944  return basic_string_view<char32_t>(__str, __len);
945}
946} // namespace string_view_literals
947} // namespace literals
948#endif
949_LIBCPP_END_NAMESPACE_STD
950
951_LIBCPP_POP_MACROS
952
953#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
954#  include <algorithm>
955#  include <concepts>
956#  include <cstdlib>
957#  include <iterator>
958#  include <type_traits>
959#endif
960
961#endif // _LIBCPP_STRING_VIEW
962