xref: /freebsd/contrib/llvm-project/libcxx/include/string_view (revision 5ca8e32633c4ffbbcd6762e5888b6a4ba0708c6c)
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/*
14
15    string_view synopsis
16
17#include <compare>
18
19namespace std {
20
21    // 7.2, Class template basic_string_view
22    template<class charT, class traits = char_traits<charT>>
23        class basic_string_view;
24
25    template<class charT, class traits>
26    inline constexpr bool ranges::enable_view<basic_string_view<charT, traits>> = true;
27
28    template<class charT, class traits>
29    inline constexpr bool ranges::enable_borrowed_range<basic_string_view<charT, traits>> = true;  // C++20
30
31    // 7.9, basic_string_view non-member comparison functions
32    template<class charT, class traits>
33    constexpr bool operator==(basic_string_view<charT, traits> x,
34                              basic_string_view<charT, traits> y) noexcept;
35    template<class charT, class traits>                                                            // Removed in C++20
36    constexpr bool operator!=(basic_string_view<charT, traits> x,
37                              basic_string_view<charT, traits> y) noexcept;
38    template<class charT, class traits>                                                            // Removed in C++20
39    constexpr bool operator< (basic_string_view<charT, traits> x,
40                                 basic_string_view<charT, traits> y) noexcept;
41    template<class charT, class traits>                                                            // Removed in C++20
42    constexpr bool operator> (basic_string_view<charT, traits> x,
43                              basic_string_view<charT, traits> y) noexcept;
44    template<class charT, class traits>                                                            // Removed in C++20
45    constexpr bool operator<=(basic_string_view<charT, traits> x,
46                                 basic_string_view<charT, traits> y) noexcept;
47    template<class charT, class traits>                                                            // Removed in C++20
48    constexpr bool operator>=(basic_string_view<charT, traits> x,
49                              basic_string_view<charT, traits> y) noexcept;
50    template<class charT, class traits>                                                            // Since C++20
51    constexpr see below operator<=>(basic_string_view<charT, traits> x,
52                                    basic_string_view<charT, traits> y) noexcept;
53
54    // see below, sufficient additional overloads of comparison functions
55
56    // 7.10, Inserters and extractors
57    template<class charT, class traits>
58      basic_ostream<charT, traits>&
59        operator<<(basic_ostream<charT, traits>& os,
60                   basic_string_view<charT, traits> str);
61
62    // basic_string_view typedef names
63    typedef basic_string_view<char> string_view;
64    typedef basic_string_view<char8_t> u8string_view; // C++20
65    typedef basic_string_view<char16_t> u16string_view;
66    typedef basic_string_view<char32_t> u32string_view;
67    typedef basic_string_view<wchar_t> wstring_view;
68
69    template<class charT, class traits = char_traits<charT>>
70    class basic_string_view {
71      public:
72      // types
73      typedef traits traits_type;
74      typedef charT value_type;
75      typedef charT* pointer;
76      typedef const charT* const_pointer;
77      typedef charT& reference;
78      typedef const charT& const_reference;
79      typedef implementation-defined const_iterator;
80      typedef const_iterator iterator;
81      typedef reverse_iterator<const_iterator> const_reverse_iterator;
82      typedef const_reverse_iterator reverse_iterator;
83      typedef size_t size_type;
84      typedef ptrdiff_t difference_type;
85      static constexpr size_type npos = size_type(-1);
86
87      // 7.3, basic_string_view constructors and assignment operators
88      constexpr basic_string_view() noexcept;
89      constexpr basic_string_view(const basic_string_view&) noexcept = default;
90      basic_string_view& operator=(const basic_string_view&) noexcept = default;
91      template<class Allocator>
92      constexpr basic_string_view(const charT* str);
93      basic_string_view(nullptr_t) = delete; // C++23
94      constexpr basic_string_view(const charT* str, size_type len);
95      template <class It, class End>
96      constexpr basic_string_view(It begin, End end); // C++20
97      template <class Range>
98      constexpr basic_string_view(Range&& r); // C++23
99
100      // 7.4, basic_string_view iterator support
101      constexpr const_iterator begin() const noexcept;
102      constexpr const_iterator end() const noexcept;
103      constexpr const_iterator cbegin() const noexcept;
104      constexpr const_iterator cend() const noexcept;
105      const_reverse_iterator rbegin() const noexcept;
106      const_reverse_iterator rend() const noexcept;
107      const_reverse_iterator crbegin() const noexcept;
108      const_reverse_iterator crend() const noexcept;
109
110      // 7.5, basic_string_view capacity
111      constexpr size_type size() const noexcept;
112      constexpr size_type length() const noexcept;
113      constexpr size_type max_size() const noexcept;
114      constexpr bool empty() const noexcept;
115
116      // 7.6, basic_string_view element access
117      constexpr const_reference operator[](size_type pos) const;
118      constexpr const_reference at(size_type pos) const;
119      constexpr const_reference front() const;
120      constexpr const_reference back() const;
121      constexpr const_pointer data() const noexcept;
122
123      // 7.7, basic_string_view modifiers
124      constexpr void remove_prefix(size_type n);
125      constexpr void remove_suffix(size_type n);
126      constexpr void swap(basic_string_view& s) noexcept;
127
128      size_type copy(charT* s, size_type n, size_type pos = 0) const;  // constexpr in C++20
129
130      constexpr basic_string_view substr(size_type pos = 0, size_type n = npos) const;
131      constexpr int compare(basic_string_view s) const noexcept;
132      constexpr int compare(size_type pos1, size_type n1, basic_string_view s) const;
133      constexpr int compare(size_type pos1, size_type n1,
134                            basic_string_view s, size_type pos2, size_type n2) const;
135      constexpr int compare(const charT* s) const;
136      constexpr int compare(size_type pos1, size_type n1, const charT* s) const;
137      constexpr int compare(size_type pos1, size_type n1,
138                            const charT* s, size_type n2) const;
139      constexpr size_type find(basic_string_view s, size_type pos = 0) const noexcept;
140      constexpr size_type find(charT c, size_type pos = 0) const noexcept;
141      constexpr size_type find(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
142      constexpr size_type find(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
143      constexpr size_type rfind(basic_string_view s, size_type pos = npos) const noexcept;
144      constexpr size_type rfind(charT c, size_type pos = npos) const noexcept;
145      constexpr size_type rfind(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
146      constexpr size_type rfind(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
147      constexpr size_type find_first_of(basic_string_view s, size_type pos = 0) const noexcept;
148      constexpr size_type find_first_of(charT c, size_type pos = 0) const noexcept;
149      constexpr size_type find_first_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
150      constexpr size_type find_first_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
151      constexpr size_type find_last_of(basic_string_view s, size_type pos = npos) const noexcept;
152      constexpr size_type find_last_of(charT c, size_type pos = npos) const noexcept;
153      constexpr size_type find_last_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
154      constexpr size_type find_last_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
155      constexpr size_type find_first_not_of(basic_string_view s, size_type pos = 0) const noexcept;
156      constexpr size_type find_first_not_of(charT c, size_type pos = 0) const noexcept;
157      constexpr size_type find_first_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
158      constexpr size_type find_first_not_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
159      constexpr size_type find_last_not_of(basic_string_view s, size_type pos = npos) const noexcept;
160      constexpr size_type find_last_not_of(charT c, size_type pos = npos) const noexcept;
161      constexpr size_type find_last_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
162      constexpr size_type find_last_not_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
163
164      constexpr bool starts_with(basic_string_view s) const noexcept; // C++20
165      constexpr bool starts_with(charT c) const noexcept;             // C++20
166      constexpr bool starts_with(const charT* s) const;               // C++20
167      constexpr bool ends_with(basic_string_view s) const noexcept;   // C++20
168      constexpr bool ends_with(charT c) const noexcept;               // C++20
169      constexpr bool ends_with(const charT* s) const;                 // C++20
170
171      constexpr bool contains(basic_string_view s) const noexcept; // C++23
172      constexpr bool contains(charT c) const noexcept;             // C++23
173      constexpr bool contains(const charT* s) const;               // C++23
174
175     private:
176      const_pointer data_;  // exposition only
177      size_type     size_;  // exposition only
178    };
179
180  // basic_string_view deduction guides
181  template<class It, class End>
182    basic_string_view(It, End) -> basic_string_view<iter_value_t<It>>; // C++20
183  template<class Range>
184    basic_string_view(Range&&) -> basic_string_view<ranges::range_value_t<Range>>; // C++23
185
186  // 7.11, Hash support
187  template <class T> struct hash;
188  template <> struct hash<string_view>;
189  template <> struct hash<u8string_view>; // C++20
190  template <> struct hash<u16string_view>;
191  template <> struct hash<u32string_view>;
192  template <> struct hash<wstring_view>;
193
194  constexpr basic_string_view<char>     operator""sv(const char *str,     size_t len) noexcept;
195  constexpr basic_string_view<wchar_t>  operator""sv(const wchar_t *str,  size_t len) noexcept;
196  constexpr basic_string_view<char8_t>  operator""sv(const char8_t *str,  size_t len) noexcept; // C++20
197  constexpr basic_string_view<char16_t> operator""sv(const char16_t *str, size_t len) noexcept;
198  constexpr basic_string_view<char32_t> operator""sv(const char32_t *str, size_t len) noexcept;
199
200}  // namespace std
201
202
203*/
204
205#include <__algorithm/min.h>
206#include <__assert> // all public C++ headers provide the assertion handler
207#include <__config>
208#include <__functional/hash.h>
209#include <__functional/unary_function.h>
210#include <__fwd/string_view.h>
211#include <__iterator/bounded_iter.h>
212#include <__iterator/concepts.h>
213#include <__iterator/iterator_traits.h>
214#include <__iterator/reverse_iterator.h>
215#include <__memory/pointer_traits.h>
216#include <__ranges/concepts.h>
217#include <__ranges/data.h>
218#include <__ranges/enable_borrowed_range.h>
219#include <__ranges/enable_view.h>
220#include <__ranges/size.h>
221#include <__string/char_traits.h>
222#include <__type_traits/is_array.h>
223#include <__type_traits/is_convertible.h>
224#include <__type_traits/is_same.h>
225#include <__type_traits/is_standard_layout.h>
226#include <__type_traits/is_trivial.h>
227#include <__type_traits/remove_cvref.h>
228#include <__type_traits/remove_reference.h>
229#include <__type_traits/type_identity.h>
230#include <cstddef>
231#include <iosfwd>
232#include <limits>
233#include <stdexcept>
234#include <version>
235
236// standard-mandated includes
237
238// [iterator.range]
239#include <__iterator/access.h>
240#include <__iterator/data.h>
241#include <__iterator/empty.h>
242#include <__iterator/reverse_access.h>
243#include <__iterator/size.h>
244
245// [string.view.synop]
246#include <compare>
247
248#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
249#  pragma GCC system_header
250#endif
251
252_LIBCPP_PUSH_MACROS
253#include <__undef_macros>
254
255
256_LIBCPP_BEGIN_NAMESPACE_STD
257
258// TODO: This is a workaround for some vendors to carry a downstream diff to accept `nullptr` in
259//       string_view constructors. This can be refactored when this exact form isn't needed anymore.
260template <class _Traits>
261_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
262inline size_t __char_traits_length_checked(const typename _Traits::char_type* __s) _NOEXCEPT {
263  // This needs to be a single statement for C++11 constexpr
264  return _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr,
265                                      "null pointer passed to non-null argument of char_traits<...>::length"),
266      _Traits::length(__s);
267}
268
269template<class _CharT, class _Traits>
270class basic_string_view {
271public:
272    // types
273    using traits_type            = _Traits;
274    using value_type             = _CharT;
275    using pointer                = _CharT*;
276    using const_pointer          = const _CharT*;
277    using reference              = _CharT&;
278    using const_reference        = const _CharT&;
279#ifdef _LIBCPP_ABI_BOUNDED_ITERATORS
280    using const_iterator         = __bounded_iter<const_pointer>;
281#else
282    using const_iterator         = const_pointer; // See [string.view.iterators]
283#endif
284    using iterator               = const_iterator;
285    using const_reverse_iterator = _VSTD::reverse_iterator<const_iterator>;
286    using reverse_iterator       = const_reverse_iterator;
287    using size_type              = size_t;
288    using difference_type        = ptrdiff_t;
289    static _LIBCPP_CONSTEXPR const size_type npos = -1; // size_type(-1);
290
291    static_assert((!is_array<value_type>::value), "Character type of basic_string_view must not be an array");
292    static_assert(( is_standard_layout<value_type>::value), "Character type of basic_string_view must be standard-layout");
293    static_assert(( is_trivial<value_type>::value), "Character type of basic_string_view must be trivial");
294    static_assert((is_same<_CharT, typename traits_type::char_type>::value),
295                  "traits_type::char_type must be the same type as CharT");
296
297    // [string.view.cons], construct/copy
298    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
299    basic_string_view() _NOEXCEPT : __data_(nullptr), __size_(0) {}
300
301    _LIBCPP_INLINE_VISIBILITY
302    basic_string_view(const basic_string_view&) _NOEXCEPT = default;
303
304    _LIBCPP_INLINE_VISIBILITY
305    basic_string_view& operator=(const basic_string_view&) _NOEXCEPT = default;
306
307    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
308    basic_string_view(const _CharT* __s, size_type __len) _NOEXCEPT
309        : __data_(__s), __size_(__len)
310    {
311#if _LIBCPP_STD_VER >= 14
312    _LIBCPP_ASSERT_UNCATEGORIZED(
313        __len <= static_cast<size_type>(numeric_limits<difference_type>::max()),
314        "string_view::string_view(_CharT *, size_t): length does not fit in difference_type");
315    _LIBCPP_ASSERT_UNCATEGORIZED(__len == 0 || __s != nullptr,
316                                 "string_view::string_view(_CharT *, size_t): received nullptr");
317#endif
318    }
319
320#if _LIBCPP_STD_VER >= 20
321    template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
322      requires (is_same_v<iter_value_t<_It>, _CharT> && !is_convertible_v<_End, size_type>)
323    constexpr _LIBCPP_HIDE_FROM_ABI basic_string_view(_It __begin, _End __end)
324       : __data_(_VSTD::to_address(__begin)), __size_(__end - __begin)
325    {
326      _LIBCPP_ASSERT_VALID_INPUT_RANGE((__end - __begin) >= 0,
327                                       "std::string_view::string_view(iterator, sentinel) received invalid range");
328    }
329#endif // _LIBCPP_STD_VER >= 20
330
331#if _LIBCPP_STD_VER >= 23
332    template <class _Range>
333      requires (
334        !is_same_v<remove_cvref_t<_Range>, basic_string_view> &&
335        ranges::contiguous_range<_Range> &&
336        ranges::sized_range<_Range> &&
337        is_same_v<ranges::range_value_t<_Range>, _CharT> &&
338        !is_convertible_v<_Range, const _CharT*> &&
339        (!requires(remove_cvref_t<_Range>& __d) {
340          __d.operator _VSTD::basic_string_view<_CharT, _Traits>();
341        })
342      )
343    constexpr explicit _LIBCPP_HIDE_FROM_ABI
344    basic_string_view(_Range&& __r) : __data_(ranges::data(__r)), __size_(ranges::size(__r)) {}
345#endif // _LIBCPP_STD_VER >= 23
346
347    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
348    basic_string_view(const _CharT* __s)
349        : __data_(__s), __size_(_VSTD::__char_traits_length_checked<_Traits>(__s)) {}
350
351#if _LIBCPP_STD_VER >= 23
352    basic_string_view(nullptr_t) = delete;
353#endif
354
355    // [string.view.iterators], iterators
356    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
357    const_iterator begin()  const _NOEXCEPT { return cbegin(); }
358
359    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
360    const_iterator end()    const _NOEXCEPT { return cend(); }
361
362    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
363    const_iterator cbegin() const _NOEXCEPT {
364#ifdef _LIBCPP_ABI_BOUNDED_ITERATORS
365        return std::__make_bounded_iter(data(), data(), data() + size());
366#else
367        return __data_;
368#endif
369    }
370
371    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
372    const_iterator cend()   const _NOEXCEPT {
373#ifdef _LIBCPP_ABI_BOUNDED_ITERATORS
374        return std::__make_bounded_iter(data() + size(), data(), data() + size());
375#else
376        return __data_ + __size_;
377#endif
378    }
379
380    _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_INLINE_VISIBILITY
381    const_reverse_iterator rbegin()   const _NOEXCEPT { return const_reverse_iterator(cend()); }
382
383    _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_INLINE_VISIBILITY
384    const_reverse_iterator rend()     const _NOEXCEPT { return const_reverse_iterator(cbegin()); }
385
386    _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_INLINE_VISIBILITY
387    const_reverse_iterator crbegin()  const _NOEXCEPT { return const_reverse_iterator(cend()); }
388
389    _LIBCPP_CONSTEXPR_SINCE_CXX17 _LIBCPP_INLINE_VISIBILITY
390    const_reverse_iterator crend()    const _NOEXCEPT { return const_reverse_iterator(cbegin()); }
391
392    // [string.view.capacity], capacity
393    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
394    size_type size()     const _NOEXCEPT { return __size_; }
395
396    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
397    size_type length()   const _NOEXCEPT { return __size_; }
398
399    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
400    size_type max_size() const _NOEXCEPT { return numeric_limits<size_type>::max() / sizeof(value_type); }
401
402    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
403    bool empty()         const _NOEXCEPT { return __size_ == 0; }
404
405    // [string.view.access], element access
406    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
407    const_reference operator[](size_type __pos) const _NOEXCEPT {
408      return _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__pos < size(), "string_view[] index out of bounds"), __data_[__pos];
409    }
410
411    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
412    const_reference at(size_type __pos) const
413    {
414        return __pos >= size()
415            ? (__throw_out_of_range("string_view::at"), __data_[0])
416            : __data_[__pos];
417    }
418
419    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
420    const_reference front() const _NOEXCEPT
421    {
422        return _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string_view::front(): string is empty"), __data_[0];
423    }
424
425    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
426    const_reference back() const _NOEXCEPT
427    {
428        return _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string_view::back(): string is empty"),
429               __data_[__size_ - 1];
430    }
431
432    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
433    const_pointer data() const _NOEXCEPT { return __data_; }
434
435    // [string.view.modifiers], modifiers:
436    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
437    void remove_prefix(size_type __n) _NOEXCEPT
438    {
439        _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__n <= size(), "remove_prefix() can't remove more than size()");
440        __data_ += __n;
441        __size_ -= __n;
442    }
443
444    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
445    void remove_suffix(size_type __n) _NOEXCEPT
446    {
447        _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__n <= size(), "remove_suffix() can't remove more than size()");
448        __size_ -= __n;
449    }
450
451    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
452    void swap(basic_string_view& __other) _NOEXCEPT
453    {
454        const value_type *__p = __data_;
455        __data_ = __other.__data_;
456        __other.__data_ = __p;
457
458        size_type __sz = __size_;
459        __size_ = __other.__size_;
460        __other.__size_ = __sz;
461    }
462
463    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
464    size_type copy(_CharT* __s, size_type __n, size_type __pos = 0) const
465    {
466        if (__pos > size())
467            __throw_out_of_range("string_view::copy");
468        size_type __rlen = _VSTD::min(__n, size() - __pos);
469        _Traits::copy(__s, data() + __pos, __rlen);
470        return __rlen;
471    }
472
473    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
474    basic_string_view substr(size_type __pos = 0, size_type __n = npos) const
475    {
476        return __pos > size()
477            ? (__throw_out_of_range("string_view::substr"), basic_string_view())
478            : basic_string_view(data() + __pos, _VSTD::min(__n, size() - __pos));
479    }
480
481    _LIBCPP_CONSTEXPR_SINCE_CXX14 int compare(basic_string_view __sv) const _NOEXCEPT
482    {
483        size_type __rlen = _VSTD::min(size(), __sv.size());
484        int __retval = _Traits::compare(data(), __sv.data(), __rlen);
485        if (__retval == 0) // first __rlen chars matched
486            __retval = size() == __sv.size() ? 0 : (size() < __sv.size() ? -1 : 1);
487        return __retval;
488    }
489
490    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
491    int compare(size_type __pos1, size_type __n1, basic_string_view __sv) const
492    {
493        return substr(__pos1, __n1).compare(__sv);
494    }
495
496    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
497    int compare(                       size_type __pos1, size_type __n1,
498                basic_string_view __sv, size_type __pos2, size_type __n2) const
499    {
500        return substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
501    }
502
503    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
504    int compare(const _CharT* __s) const _NOEXCEPT
505    {
506        return compare(basic_string_view(__s));
507    }
508
509    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
510    int compare(size_type __pos1, size_type __n1, const _CharT* __s) const
511    {
512        return substr(__pos1, __n1).compare(basic_string_view(__s));
513    }
514
515    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
516    int compare(size_type __pos1, size_type __n1, const _CharT* __s, size_type __n2) const
517    {
518        return substr(__pos1, __n1).compare(basic_string_view(__s, __n2));
519    }
520
521    // find
522    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
523    size_type find(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT
524    {
525        _LIBCPP_ASSERT_UNCATEGORIZED(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
526        return std::__str_find<value_type, size_type, traits_type, npos>
527            (data(), size(), __s.data(), __pos, __s.size());
528    }
529
530    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
531    size_type find(_CharT __c, size_type __pos = 0) const _NOEXCEPT
532    {
533        return std::__str_find<value_type, size_type, traits_type, npos>
534            (data(), size(), __c, __pos);
535    }
536
537    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
538    size_type find(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
539    {
540        _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string_view::find(): received nullptr");
541        return std::__str_find<value_type, size_type, traits_type, npos>
542            (data(), size(), __s, __pos, __n);
543    }
544
545    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
546    size_type find(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT
547    {
548        _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string_view::find(): received nullptr");
549        return std::__str_find<value_type, size_type, traits_type, npos>
550            (data(), size(), __s, __pos, traits_type::length(__s));
551    }
552
553    // rfind
554    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
555    size_type rfind(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT
556    {
557        _LIBCPP_ASSERT_UNCATEGORIZED(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
558        return std::__str_rfind<value_type, size_type, traits_type, npos>
559            (data(), size(), __s.data(), __pos, __s.size());
560    }
561
562    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
563    size_type rfind(_CharT __c, size_type __pos = npos) const _NOEXCEPT
564    {
565        return std::__str_rfind<value_type, size_type, traits_type, npos>
566            (data(), size(), __c, __pos);
567    }
568
569    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
570    size_type rfind(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
571    {
572        _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string_view::rfind(): received nullptr");
573        return std::__str_rfind<value_type, size_type, traits_type, npos>
574            (data(), size(), __s, __pos, __n);
575    }
576
577    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
578    size_type rfind(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
579    {
580        _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string_view::rfind(): received nullptr");
581        return std::__str_rfind<value_type, size_type, traits_type, npos>
582            (data(), size(), __s, __pos, traits_type::length(__s));
583    }
584
585    // find_first_of
586    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
587    size_type find_first_of(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT
588    {
589        _LIBCPP_ASSERT_UNCATEGORIZED(__s.size() == 0 || __s.data() != nullptr,
590                                     "string_view::find_first_of(): received nullptr");
591        return std::__str_find_first_of<value_type, size_type, traits_type, npos>
592            (data(), size(), __s.data(), __pos, __s.size());
593    }
594
595    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
596    size_type find_first_of(_CharT __c, size_type __pos = 0) const _NOEXCEPT
597    { return find(__c, __pos); }
598
599    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
600    size_type find_first_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
601    {
602        _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string_view::find_first_of(): received nullptr");
603        return std::__str_find_first_of<value_type, size_type, traits_type, npos>
604            (data(), size(), __s, __pos, __n);
605    }
606
607    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
608    size_type find_first_of(const _CharT* __s, size_type __pos=0) const _NOEXCEPT
609    {
610        _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string_view::find_first_of(): received nullptr");
611        return std::__str_find_first_of<value_type, size_type, traits_type, npos>
612            (data(), size(), __s, __pos, traits_type::length(__s));
613    }
614
615    // find_last_of
616    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
617    size_type find_last_of(basic_string_view __s, size_type __pos=npos) const _NOEXCEPT
618    {
619        _LIBCPP_ASSERT_UNCATEGORIZED(__s.size() == 0 || __s.data() != nullptr,
620                                     "string_view::find_last_of(): received nullptr");
621        return std::__str_find_last_of<value_type, size_type, traits_type, npos>
622            (data(), size(), __s.data(), __pos, __s.size());
623    }
624
625    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
626    size_type find_last_of(_CharT __c, size_type __pos = npos) const _NOEXCEPT
627    { return rfind(__c, __pos); }
628
629    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
630    size_type find_last_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
631    {
632        _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string_view::find_last_of(): received nullptr");
633        return std::__str_find_last_of<value_type, size_type, traits_type, npos>
634            (data(), size(), __s, __pos, __n);
635    }
636
637    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
638    size_type find_last_of(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
639    {
640        _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string_view::find_last_of(): received nullptr");
641        return std::__str_find_last_of<value_type, size_type, traits_type, npos>
642            (data(), size(), __s, __pos, traits_type::length(__s));
643    }
644
645    // find_first_not_of
646    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
647    size_type find_first_not_of(basic_string_view __s, size_type __pos=0) const _NOEXCEPT
648    {
649        _LIBCPP_ASSERT_UNCATEGORIZED(__s.size() == 0 || __s.data() != nullptr,
650                                     "string_view::find_first_not_of(): received nullptr");
651        return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
652            (data(), size(), __s.data(), __pos, __s.size());
653    }
654
655    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
656    size_type find_first_not_of(_CharT __c, size_type __pos=0) const _NOEXCEPT
657    {
658        return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
659            (data(), size(), __c, __pos);
660    }
661
662    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
663    size_type find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
664    {
665        _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string_view::find_first_not_of(): received nullptr");
666        return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
667            (data(), size(), __s, __pos, __n);
668    }
669
670    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
671    size_type find_first_not_of(const _CharT* __s, size_type __pos=0) const _NOEXCEPT
672    {
673        _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string_view::find_first_not_of(): received nullptr");
674        return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>
675            (data(), size(), __s, __pos, traits_type::length(__s));
676    }
677
678    // find_last_not_of
679    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
680    size_type find_last_not_of(basic_string_view __s, size_type __pos=npos) const _NOEXCEPT
681    {
682        _LIBCPP_ASSERT_UNCATEGORIZED(__s.size() == 0 || __s.data() != nullptr,
683                                     "string_view::find_last_not_of(): received nullptr");
684        return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
685            (data(), size(), __s.data(), __pos, __s.size());
686    }
687
688    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
689    size_type find_last_not_of(_CharT __c, size_type __pos=npos) const _NOEXCEPT
690    {
691        return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
692            (data(), size(), __c, __pos);
693    }
694
695    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
696    size_type find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
697    {
698        _LIBCPP_ASSERT_UNCATEGORIZED(__n == 0 || __s != nullptr, "string_view::find_last_not_of(): received nullptr");
699        return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
700            (data(), size(), __s, __pos, __n);
701    }
702
703    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
704    size_type find_last_not_of(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
705    {
706        _LIBCPP_ASSERT_UNCATEGORIZED(__s != nullptr, "string_view::find_last_not_of(): received nullptr");
707        return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>
708            (data(), size(), __s, __pos, traits_type::length(__s));
709    }
710
711#if _LIBCPP_STD_VER >= 20
712    constexpr _LIBCPP_INLINE_VISIBILITY
713    bool starts_with(basic_string_view __s) const noexcept
714    { return size() >= __s.size() && compare(0, __s.size(), __s) == 0; }
715
716    constexpr _LIBCPP_INLINE_VISIBILITY
717    bool starts_with(value_type __c) const noexcept
718    { return !empty() && _Traits::eq(front(), __c); }
719
720    constexpr _LIBCPP_INLINE_VISIBILITY
721    bool starts_with(const value_type* __s) const noexcept
722    { return starts_with(basic_string_view(__s)); }
723
724    constexpr _LIBCPP_INLINE_VISIBILITY
725    bool ends_with(basic_string_view __s) const noexcept
726    { return size() >= __s.size() && compare(size() - __s.size(), npos, __s) == 0; }
727
728    constexpr _LIBCPP_INLINE_VISIBILITY
729    bool ends_with(value_type __c) const noexcept
730    { return !empty() && _Traits::eq(back(), __c); }
731
732    constexpr _LIBCPP_INLINE_VISIBILITY
733    bool ends_with(const value_type* __s) const noexcept
734    { return ends_with(basic_string_view(__s)); }
735#endif
736
737#if _LIBCPP_STD_VER >= 23
738    constexpr _LIBCPP_INLINE_VISIBILITY
739    bool contains(basic_string_view __sv) const noexcept
740    { return find(__sv) != npos; }
741
742    constexpr _LIBCPP_INLINE_VISIBILITY
743    bool contains(value_type __c) const noexcept
744    { return find(__c) != npos; }
745
746    constexpr _LIBCPP_INLINE_VISIBILITY
747    bool contains(const value_type* __s) const
748    { return find(__s) != npos; }
749#endif
750
751private:
752    const   value_type* __data_;
753    size_type           __size_;
754};
755_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(basic_string_view);
756
757#if _LIBCPP_STD_VER >= 20
758template <class _CharT, class _Traits>
759inline constexpr bool ranges::enable_view<basic_string_view<_CharT, _Traits>> = true;
760
761template <class _CharT, class _Traits>
762inline constexpr bool ranges::enable_borrowed_range<basic_string_view<_CharT, _Traits> > = true;
763#endif // _LIBCPP_STD_VER >= 20
764
765// [string.view.deduct]
766
767#if _LIBCPP_STD_VER >= 20
768template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
769  basic_string_view(_It, _End) -> basic_string_view<iter_value_t<_It>>;
770#endif // _LIBCPP_STD_VER >= 20
771
772
773#if _LIBCPP_STD_VER >= 23
774template <ranges::contiguous_range _Range>
775  basic_string_view(_Range) -> basic_string_view<ranges::range_value_t<_Range>>;
776#endif
777
778// [string.view.comparison]
779// operator ==
780template<class _CharT, class _Traits>
781_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
782bool operator==(basic_string_view<_CharT, _Traits> __lhs,
783                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
784{
785    if (__lhs.size() != __rhs.size()) return false;
786    return __lhs.compare(__rhs) == 0;
787}
788
789// The dummy default template parameters are used to work around a MSVC issue with mangling, see VSO-409326 for details.
790// This applies to the other sufficient overloads below for the other comparison operators.
791template<class _CharT, class _Traits, int = 1>
792_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
793bool operator==(basic_string_view<_CharT, _Traits> __lhs,
794                __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT
795{
796    if (__lhs.size() != __rhs.size()) return false;
797    return __lhs.compare(__rhs) == 0;
798}
799
800#if _LIBCPP_STD_VER < 20
801// This overload is automatically generated in C++20.
802template<class _CharT, class _Traits, int = 2>
803_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
804bool operator==(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
805                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
806{
807    if (__lhs.size() != __rhs.size()) return false;
808    return __lhs.compare(__rhs) == 0;
809}
810#endif // _LIBCPP_STD_VER >= 20
811
812// operator <=>
813
814#if _LIBCPP_STD_VER >= 20
815
816template <class _CharT, class _Traits>
817_LIBCPP_HIDE_FROM_ABI constexpr auto
818operator<=>(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) noexcept {
819    if constexpr (requires { typename _Traits::comparison_category; }) {
820        // [string.view]/4
821        static_assert(
822            __comparison_category<typename _Traits::comparison_category>,
823            "return type is not a comparison category type");
824        return static_cast<typename _Traits::comparison_category>(__lhs.compare(__rhs) <=> 0);
825    } else {
826        return static_cast<weak_ordering>(__lhs.compare(__rhs) <=> 0);
827    }
828}
829
830template <class _CharT, class _Traits, int = 1>
831_LIBCPP_HIDE_FROM_ABI constexpr auto operator<=>(
832    basic_string_view<_CharT, _Traits> __lhs, type_identity_t<basic_string_view<_CharT, _Traits>> __rhs) noexcept {
833    if constexpr (requires { typename _Traits::comparison_category; }) {
834        // [string.view]/4
835        static_assert(
836            __comparison_category<typename _Traits::comparison_category>,
837            "return type is not a comparison category type");
838        return static_cast<typename _Traits::comparison_category>(__lhs.compare(__rhs) <=> 0);
839    } else {
840        return static_cast<weak_ordering>(__lhs.compare(__rhs) <=> 0);
841    }
842}
843
844#else //  _LIBCPP_STD_VER >= 20
845
846// operator !=
847template<class _CharT, class _Traits>
848_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
849bool operator!=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
850{
851    if (__lhs.size() != __rhs.size())
852        return true;
853    return __lhs.compare(__rhs) != 0;
854}
855
856template<class _CharT, class _Traits, int = 1>
857_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
858bool operator!=(basic_string_view<_CharT, _Traits> __lhs,
859                __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT
860{
861    if (__lhs.size() != __rhs.size())
862        return true;
863    return __lhs.compare(__rhs) != 0;
864}
865
866template<class _CharT, class _Traits, int = 2>
867_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
868bool operator!=(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
869                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
870{
871    if (__lhs.size() != __rhs.size())
872        return true;
873    return __lhs.compare(__rhs) != 0;
874}
875
876
877// operator <
878template<class _CharT, class _Traits>
879_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
880bool operator<(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
881{
882    return __lhs.compare(__rhs) < 0;
883}
884
885template<class _CharT, class _Traits, int = 1>
886_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
887bool operator<(basic_string_view<_CharT, _Traits> __lhs,
888                __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT
889{
890    return __lhs.compare(__rhs) < 0;
891}
892
893template<class _CharT, class _Traits, int = 2>
894_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
895bool operator<(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
896                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
897{
898    return __lhs.compare(__rhs) < 0;
899}
900
901
902// operator >
903template<class _CharT, class _Traits>
904_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
905bool operator> (basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
906{
907    return __lhs.compare(__rhs) > 0;
908}
909
910template<class _CharT, class _Traits, int = 1>
911_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
912bool operator>(basic_string_view<_CharT, _Traits> __lhs,
913                __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT
914{
915    return __lhs.compare(__rhs) > 0;
916}
917
918template<class _CharT, class _Traits, int = 2>
919_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
920bool operator>(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
921                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
922{
923    return __lhs.compare(__rhs) > 0;
924}
925
926
927// operator <=
928template<class _CharT, class _Traits>
929_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
930bool operator<=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
931{
932    return __lhs.compare(__rhs) <= 0;
933}
934
935template<class _CharT, class _Traits, int = 1>
936_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
937bool operator<=(basic_string_view<_CharT, _Traits> __lhs,
938                __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT
939{
940    return __lhs.compare(__rhs) <= 0;
941}
942
943template<class _CharT, class _Traits, int = 2>
944_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
945bool operator<=(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
946                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
947{
948    return __lhs.compare(__rhs) <= 0;
949}
950
951
952// operator >=
953template<class _CharT, class _Traits>
954_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
955bool operator>=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
956{
957    return __lhs.compare(__rhs) >= 0;
958}
959
960
961template<class _CharT, class _Traits, int = 1>
962_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
963bool operator>=(basic_string_view<_CharT, _Traits> __lhs,
964                __type_identity_t<basic_string_view<_CharT, _Traits> > __rhs) _NOEXCEPT
965{
966    return __lhs.compare(__rhs) >= 0;
967}
968
969template<class _CharT, class _Traits, int = 2>
970_LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_INLINE_VISIBILITY
971bool operator>=(__type_identity_t<basic_string_view<_CharT, _Traits> > __lhs,
972                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
973{
974    return __lhs.compare(__rhs) >= 0;
975}
976
977#endif //  _LIBCPP_STD_VER >= 20
978
979template<class _CharT, class _Traits>
980_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
981operator<<(basic_ostream<_CharT, _Traits>& __os,
982           basic_string_view<_CharT, _Traits> __str);
983
984// [string.view.hash]
985template<class _CharT>
986struct __string_view_hash : public __unary_function<basic_string_view<_CharT, char_traits<_CharT> >, size_t>
987{
988    _LIBCPP_INLINE_VISIBILITY
989    size_t operator()(const basic_string_view<_CharT, char_traits<_CharT> > __val) const _NOEXCEPT {
990        return std::__do_string_hash(__val.data(), __val.data() + __val.size());
991    }
992};
993
994template <>
995struct hash<basic_string_view<char, char_traits<char> > > : __string_view_hash<char> {};
996
997#ifndef _LIBCPP_HAS_NO_CHAR8_T
998template <>
999struct hash<basic_string_view<char8_t, char_traits<char8_t> > > : __string_view_hash<char8_t> {};
1000#endif
1001
1002template <>
1003struct hash<basic_string_view<char16_t, char_traits<char16_t> > > : __string_view_hash<char16_t> {};
1004
1005template <>
1006struct hash<basic_string_view<char32_t, char_traits<char32_t> > > : __string_view_hash<char32_t> {};
1007
1008#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
1009template <>
1010struct hash<basic_string_view<wchar_t, char_traits<wchar_t> > > : __string_view_hash<wchar_t> {};
1011#endif
1012
1013#if _LIBCPP_STD_VER >= 14
1014inline namespace literals
1015{
1016  inline namespace string_view_literals
1017  {
1018    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1019    basic_string_view<char> operator""sv(const char *__str, size_t __len) _NOEXCEPT
1020    {
1021        return basic_string_view<char> (__str, __len);
1022    }
1023
1024#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
1025    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1026    basic_string_view<wchar_t> operator""sv(const wchar_t *__str, size_t __len) _NOEXCEPT
1027    {
1028        return basic_string_view<wchar_t> (__str, __len);
1029    }
1030#endif
1031
1032#ifndef _LIBCPP_HAS_NO_CHAR8_T
1033    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1034    basic_string_view<char8_t> operator""sv(const char8_t *__str, size_t __len) _NOEXCEPT
1035    {
1036        return basic_string_view<char8_t> (__str, __len);
1037    }
1038#endif
1039
1040    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1041    basic_string_view<char16_t> operator""sv(const char16_t *__str, size_t __len) _NOEXCEPT
1042    {
1043        return basic_string_view<char16_t> (__str, __len);
1044    }
1045
1046    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
1047    basic_string_view<char32_t> operator""sv(const char32_t *__str, size_t __len) _NOEXCEPT
1048    {
1049        return basic_string_view<char32_t> (__str, __len);
1050    }
1051  } // namespace string_view_literals
1052} // namespace literals
1053#endif
1054_LIBCPP_END_NAMESPACE_STD
1055
1056_LIBCPP_POP_MACROS
1057
1058#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1059#  include <algorithm>
1060#  include <concepts>
1061#  include <cstdlib>
1062#  include <iterator>
1063#  include <type_traits>
1064#endif
1065
1066#endif // _LIBCPP_STRING_VIEW
1067