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/*
14string_view synopsis
15
16namespace std {
17
18    // 7.2, Class template basic_string_view
19    template<class charT, class traits = char_traits<charT>>
20        class basic_string_view;
21
22    template<class charT, class traits>
23    inline constexpr bool ranges::enable_view<basic_string_view<charT, traits>> = true;
24
25    template<class charT, class traits>
26    inline constexpr bool ranges::enable_borrowed_range<basic_string_view<charT, traits>> = true;  // C++20
27
28    // 7.9, basic_string_view non-member comparison functions
29    template<class charT, class traits>
30    constexpr bool operator==(basic_string_view<charT, traits> x,
31                              basic_string_view<charT, traits> y) noexcept;
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>
36    constexpr bool operator< (basic_string_view<charT, traits> x,
37                                 basic_string_view<charT, traits> y) noexcept;
38    template<class charT, class traits>
39    constexpr bool operator> (basic_string_view<charT, traits> x,
40                              basic_string_view<charT, traits> y) noexcept;
41    template<class charT, class traits>
42    constexpr bool operator<=(basic_string_view<charT, traits> x,
43                                 basic_string_view<charT, traits> y) noexcept;
44    template<class charT, class traits>
45    constexpr bool operator>=(basic_string_view<charT, traits> x,
46                              basic_string_view<charT, traits> y) noexcept;
47    // see below, sufficient additional overloads of comparison functions
48
49    // 7.10, Inserters and extractors
50    template<class charT, class traits>
51      basic_ostream<charT, traits>&
52        operator<<(basic_ostream<charT, traits>& os,
53                   basic_string_view<charT, traits> str);
54
55    // basic_string_view typedef names
56    typedef basic_string_view<char> string_view;
57    typedef basic_string_view<char8_t> u8string_view; // C++20
58    typedef basic_string_view<char16_t> u16string_view;
59    typedef basic_string_view<char32_t> u32string_view;
60    typedef basic_string_view<wchar_t> wstring_view;
61
62    template<class charT, class traits = char_traits<charT>>
63    class basic_string_view {
64      public:
65      // types
66      typedef traits traits_type;
67      typedef charT value_type;
68      typedef charT* pointer;
69      typedef const charT* const_pointer;
70      typedef charT& reference;
71      typedef const charT& const_reference;
72      typedef implementation-defined const_iterator;
73      typedef const_iterator iterator;
74      typedef reverse_iterator<const_iterator> const_reverse_iterator;
75      typedef const_reverse_iterator reverse_iterator;
76      typedef size_t size_type;
77      typedef ptrdiff_t difference_type;
78      static constexpr size_type npos = size_type(-1);
79
80      // 7.3, basic_string_view constructors and assignment operators
81      constexpr basic_string_view() noexcept;
82      constexpr basic_string_view(const basic_string_view&) noexcept = default;
83      basic_string_view& operator=(const basic_string_view&) noexcept = default;
84      template<class Allocator>
85      constexpr basic_string_view(const charT* str);
86      basic_string_view(nullptr_t) = delete; // C++2b
87      constexpr basic_string_view(const charT* str, size_type len);
88      template <class It, class End>
89      constexpr basic_string_view(It begin, End end); // C++20
90      template <class Range>
91      constexpr basic_string_view(Range&& r); // C++23
92
93      // 7.4, basic_string_view iterator support
94      constexpr const_iterator begin() const noexcept;
95      constexpr const_iterator end() const noexcept;
96      constexpr const_iterator cbegin() const noexcept;
97      constexpr const_iterator cend() const noexcept;
98      const_reverse_iterator rbegin() const noexcept;
99      const_reverse_iterator rend() const noexcept;
100      const_reverse_iterator crbegin() const noexcept;
101      const_reverse_iterator crend() const noexcept;
102
103      // 7.5, basic_string_view capacity
104      constexpr size_type size() const noexcept;
105      constexpr size_type length() const noexcept;
106      constexpr size_type max_size() const noexcept;
107      constexpr bool empty() const noexcept;
108
109      // 7.6, basic_string_view element access
110      constexpr const_reference operator[](size_type pos) const;
111      constexpr const_reference at(size_type pos) const;
112      constexpr const_reference front() const;
113      constexpr const_reference back() const;
114      constexpr const_pointer data() const noexcept;
115
116      // 7.7, basic_string_view modifiers
117      constexpr void remove_prefix(size_type n);
118      constexpr void remove_suffix(size_type n);
119      constexpr void swap(basic_string_view& s) noexcept;
120
121      size_type copy(charT* s, size_type n, size_type pos = 0) const;  // constexpr in C++20
122
123      constexpr basic_string_view substr(size_type pos = 0, size_type n = npos) const;
124      constexpr int compare(basic_string_view s) const noexcept;
125      constexpr int compare(size_type pos1, size_type n1, basic_string_view s) const;
126      constexpr int compare(size_type pos1, size_type n1,
127                            basic_string_view s, size_type pos2, size_type n2) const;
128      constexpr int compare(const charT* s) const;
129      constexpr int compare(size_type pos1, size_type n1, const charT* s) const;
130      constexpr int compare(size_type pos1, size_type n1,
131                            const charT* s, size_type n2) const;
132      constexpr size_type find(basic_string_view s, size_type pos = 0) const noexcept;
133      constexpr size_type find(charT c, size_type pos = 0) const noexcept;
134      constexpr size_type find(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
135      constexpr size_type find(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
136      constexpr size_type rfind(basic_string_view s, size_type pos = npos) const noexcept;
137      constexpr size_type rfind(charT c, size_type pos = npos) const noexcept;
138      constexpr size_type rfind(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
139      constexpr size_type rfind(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
140      constexpr size_type find_first_of(basic_string_view s, size_type pos = 0) const noexcept;
141      constexpr size_type find_first_of(charT c, size_type pos = 0) const noexcept;
142      constexpr size_type find_first_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
143      constexpr size_type find_first_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
144      constexpr size_type find_last_of(basic_string_view s, size_type pos = npos) const noexcept;
145      constexpr size_type find_last_of(charT c, size_type pos = npos) const noexcept;
146      constexpr size_type find_last_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
147      constexpr size_type find_last_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
148      constexpr size_type find_first_not_of(basic_string_view s, size_type pos = 0) const noexcept;
149      constexpr size_type find_first_not_of(charT c, size_type pos = 0) const noexcept;
150      constexpr size_type find_first_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
151      constexpr size_type find_first_not_of(const charT* s, size_type pos = 0) const noexcept; // noexcept as an extension
152      constexpr size_type find_last_not_of(basic_string_view s, size_type pos = npos) const noexcept;
153      constexpr size_type find_last_not_of(charT c, size_type pos = npos) const noexcept;
154      constexpr size_type find_last_not_of(const charT* s, size_type pos, size_type n) const noexcept; // noexcept as an extension
155      constexpr size_type find_last_not_of(const charT* s, size_type pos = npos) const noexcept; // noexcept as an extension
156
157      constexpr bool starts_with(basic_string_view s) const noexcept; // C++20
158      constexpr bool starts_with(charT c) const noexcept;             // C++20
159      constexpr bool starts_with(const charT* s) const;               // C++20
160      constexpr bool ends_with(basic_string_view s) const noexcept;   // C++20
161      constexpr bool ends_with(charT c) const noexcept;               // C++20
162      constexpr bool ends_with(const charT* s) const;                 // C++20
163
164      constexpr bool contains(basic_string_view s) const noexcept; // C++2b
165      constexpr bool contains(charT c) const noexcept;             // C++2b
166      constexpr bool contains(const charT* s) const;               // C++2b
167
168     private:
169      const_pointer data_;  // exposition only
170      size_type     size_;  // exposition only
171    };
172
173  // basic_string_view deduction guides
174  template<class It, class End>
175    basic_string_view(It, End) -> basic_string_view<iter_value_t<It>>; // C++20
176  template<class Range>
177    basic_string_view(Range&&) -> basic_string_view<ranges::range_value_t<Range>>; // C++23
178
179  // 7.11, Hash support
180  template <class T> struct hash;
181  template <> struct hash<string_view>;
182  template <> struct hash<u8string_view>; // C++20
183  template <> struct hash<u16string_view>;
184  template <> struct hash<u32string_view>;
185  template <> struct hash<wstring_view>;
186
187  constexpr basic_string_view<char>     operator "" sv( const char *str,     size_t len ) noexcept;
188  constexpr basic_string_view<wchar_t>  operator "" sv( const wchar_t *str,  size_t len ) noexcept;
189  constexpr basic_string_view<char8_t>  operator "" sv( const char8_t *str,  size_t len ) noexcept; // C++20
190  constexpr basic_string_view<char16_t> operator "" sv( const char16_t *str, size_t len ) noexcept;
191  constexpr basic_string_view<char32_t> operator "" sv( const char32_t *str, size_t len ) noexcept;
192
193}  // namespace std
194
195
196*/
197
198#include <__algorithm/min.h>
199#include <__assert>
200#include <__config>
201#include <__ranges/concepts.h>
202#include <__ranges/data.h>
203#include <__ranges/enable_borrowed_range.h>
204#include <__ranges/enable_view.h>
205#include <__ranges/size.h>
206#include <__string>
207#include <compare>
208#include <iosfwd>
209#include <iterator>
210#include <limits>
211#include <stdexcept>
212#include <type_traits>
213#include <version>
214
215#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
216#  pragma GCC system_header
217#endif
218
219_LIBCPP_PUSH_MACROS
220#include <__undef_macros>
221
222
223_LIBCPP_BEGIN_NAMESPACE_STD
224
225template<class _CharT, class _Traits = char_traits<_CharT> >
226    class _LIBCPP_TEMPLATE_VIS basic_string_view;
227
228typedef basic_string_view<char>     string_view;
229#ifndef _LIBCPP_HAS_NO_CHAR8_T
230typedef basic_string_view<char8_t>  u8string_view;
231#endif
232typedef basic_string_view<char16_t> u16string_view;
233typedef basic_string_view<char32_t> u32string_view;
234#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
235typedef basic_string_view<wchar_t>  wstring_view;
236#endif
237
238// TODO: This is a workaround for some vendors to carry a downstream diff to accept `nullptr` in
239//       string_view constructors. This can be refactored when this exact form isn't needed anymore.
240template <class _Traits>
241_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
242inline size_t __char_traits_length_checked(const typename _Traits::char_type* __s) _NOEXCEPT {
243  // This needs to be a single statement for C++11 constexpr
244  return _LIBCPP_ASSERT(__s != nullptr, "null pointer passed to non-null argument of char_traits<...>::length"), _Traits::length(__s);
245}
246
247template<class _CharT, class _Traits>
248class
249    _LIBCPP_PREFERRED_NAME(string_view)
250#ifndef _LIBCPP_HAS_NO_CHAR8_T
251    _LIBCPP_PREFERRED_NAME(u8string_view)
252#endif
253    _LIBCPP_PREFERRED_NAME(u16string_view)
254    _LIBCPP_PREFERRED_NAME(u32string_view)
255    _LIBCPP_IF_WIDE_CHARACTERS(_LIBCPP_PREFERRED_NAME(wstring_view))
256    basic_string_view {
257public:
258    // types
259    typedef _Traits                                    traits_type;
260    typedef _CharT                                     value_type;
261    typedef _CharT*                                    pointer;
262    typedef const _CharT*                              const_pointer;
263    typedef _CharT&                                    reference;
264    typedef const _CharT&                              const_reference;
265    typedef const_pointer                              const_iterator; // See [string.view.iterators]
266    typedef const_iterator                             iterator;
267    typedef _VSTD::reverse_iterator<const_iterator>    const_reverse_iterator;
268    typedef const_reverse_iterator                     reverse_iterator;
269    typedef size_t                                     size_type;
270    typedef ptrdiff_t                                  difference_type;
271    static _LIBCPP_CONSTEXPR const size_type npos = -1; // size_type(-1);
272
273    static_assert((!is_array<value_type>::value), "Character type of basic_string_view must not be an array");
274    static_assert(( is_standard_layout<value_type>::value), "Character type of basic_string_view must be standard-layout");
275    static_assert(( is_trivial<value_type>::value), "Character type of basic_string_view must be trivial");
276    static_assert((is_same<_CharT, typename traits_type::char_type>::value),
277                  "traits_type::char_type must be the same type as CharT");
278
279    // [string.view.cons], construct/copy
280    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
281    basic_string_view() _NOEXCEPT : __data (nullptr), __size(0) {}
282
283    _LIBCPP_INLINE_VISIBILITY
284    basic_string_view(const basic_string_view&) _NOEXCEPT = default;
285
286    _LIBCPP_INLINE_VISIBILITY
287    basic_string_view& operator=(const basic_string_view&) _NOEXCEPT = default;
288
289    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
290    basic_string_view(const _CharT* __s, size_type __len) _NOEXCEPT
291        : __data(__s), __size(__len)
292    {
293#if _LIBCPP_STD_VER > 11
294    _LIBCPP_ASSERT(__len == 0 || __s != nullptr, "string_view::string_view(_CharT *, size_t): received nullptr");
295#endif
296    }
297
298#if _LIBCPP_STD_VER > 17
299    template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
300      requires (is_same_v<iter_value_t<_It>, _CharT> && !is_convertible_v<_End, size_type>)
301    constexpr _LIBCPP_HIDE_FROM_ABI basic_string_view(_It __begin, _End __end)
302       : __data(_VSTD::to_address(__begin)), __size(__end - __begin)
303    {
304      _LIBCPP_ASSERT((__end - __begin) >= 0, "std::string_view::string_view(iterator, sentinel) received invalid range");
305    }
306#endif // _LIBCPP_STD_VER > 17
307
308#if _LIBCPP_STD_VER > 20 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
309    template <class _Range>
310      requires (
311        !is_same_v<remove_cvref_t<_Range>, basic_string_view> &&
312        ranges::contiguous_range<_Range> &&
313        ranges::sized_range<_Range> &&
314        is_same_v<ranges::range_value_t<_Range>, _CharT> &&
315        !is_convertible_v<_Range, const _CharT*> &&
316        (!requires(remove_cvref_t<_Range>& d) {
317          d.operator _VSTD::basic_string_view<_CharT, _Traits>();
318        }) &&
319        (!requires {
320         typename remove_reference_t<_Range>::traits_type;
321        } || is_same_v<typename remove_reference_t<_Range>::traits_type, _Traits>)
322      )
323    constexpr _LIBCPP_HIDE_FROM_ABI
324    basic_string_view(_Range&& __r) : __data(ranges::data(__r)), __size(ranges::size(__r)) {}
325#endif // _LIBCPP_STD_VER > 20 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
326
327    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
328    basic_string_view(const _CharT* __s)
329        : __data(__s), __size(_VSTD::__char_traits_length_checked<_Traits>(__s)) {}
330
331#if _LIBCPP_STD_VER > 20
332    basic_string_view(nullptr_t) = delete;
333#endif
334
335    // [string.view.iterators], iterators
336    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
337    const_iterator begin()  const _NOEXCEPT { return cbegin(); }
338
339    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
340    const_iterator end()    const _NOEXCEPT { return cend(); }
341
342    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
343    const_iterator cbegin() const _NOEXCEPT { return __data; }
344
345    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
346    const_iterator cend()   const _NOEXCEPT { return __data + __size; }
347
348    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
349    const_reverse_iterator rbegin()   const _NOEXCEPT { return const_reverse_iterator(cend()); }
350
351    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
352    const_reverse_iterator rend()     const _NOEXCEPT { return const_reverse_iterator(cbegin()); }
353
354    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
355    const_reverse_iterator crbegin()  const _NOEXCEPT { return const_reverse_iterator(cend()); }
356
357    _LIBCPP_CONSTEXPR_AFTER_CXX14 _LIBCPP_INLINE_VISIBILITY
358    const_reverse_iterator crend()    const _NOEXCEPT { return const_reverse_iterator(cbegin()); }
359
360    // [string.view.capacity], capacity
361    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
362    size_type size()     const _NOEXCEPT { return __size; }
363
364    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
365    size_type length()   const _NOEXCEPT { return __size; }
366
367    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
368    size_type max_size() const _NOEXCEPT { return numeric_limits<size_type>::max() / sizeof(value_type); }
369
370    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
371    bool empty()         const _NOEXCEPT { return __size == 0; }
372
373    // [string.view.access], element access
374    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
375    const_reference operator[](size_type __pos) const _NOEXCEPT {
376      return _LIBCPP_ASSERT(__pos < size(), "string_view[] index out of bounds"), __data[__pos];
377    }
378
379    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
380    const_reference at(size_type __pos) const
381    {
382        return __pos >= size()
383            ? (__throw_out_of_range("string_view::at"), __data[0])
384            : __data[__pos];
385    }
386
387    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
388    const_reference front() const _NOEXCEPT
389    {
390        return _LIBCPP_ASSERT(!empty(), "string_view::front(): string is empty"), __data[0];
391    }
392
393    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
394    const_reference back() const _NOEXCEPT
395    {
396        return _LIBCPP_ASSERT(!empty(), "string_view::back(): string is empty"), __data[__size-1];
397    }
398
399    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
400    const_pointer data() const _NOEXCEPT { return __data; }
401
402    // [string.view.modifiers], modifiers:
403    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
404    void remove_prefix(size_type __n) _NOEXCEPT
405    {
406        _LIBCPP_ASSERT(__n <= size(), "remove_prefix() can't remove more than size()");
407        __data += __n;
408        __size -= __n;
409    }
410
411    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
412    void remove_suffix(size_type __n) _NOEXCEPT
413    {
414        _LIBCPP_ASSERT(__n <= size(), "remove_suffix() can't remove more than size()");
415        __size -= __n;
416    }
417
418    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
419    void swap(basic_string_view& __other) _NOEXCEPT
420    {
421        const value_type *__p = __data;
422        __data = __other.__data;
423        __other.__data = __p;
424
425        size_type __sz = __size;
426        __size = __other.__size;
427        __other.__size = __sz;
428    }
429
430    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
431    size_type copy(_CharT* __s, size_type __n, size_type __pos = 0) const
432    {
433        if (__pos > size())
434            __throw_out_of_range("string_view::copy");
435        size_type __rlen = _VSTD::min(__n, size() - __pos);
436        _Traits::copy(__s, data() + __pos, __rlen);
437        return __rlen;
438    }
439
440    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
441    basic_string_view substr(size_type __pos = 0, size_type __n = npos) const
442    {
443        return __pos > size()
444            ? (__throw_out_of_range("string_view::substr"), basic_string_view())
445            : basic_string_view(data() + __pos, _VSTD::min(__n, size() - __pos));
446    }
447
448    _LIBCPP_CONSTEXPR_AFTER_CXX11 int compare(basic_string_view __sv) const _NOEXCEPT
449    {
450        size_type __rlen = _VSTD::min( size(), __sv.size());
451        int __retval = _Traits::compare(data(), __sv.data(), __rlen);
452        if ( __retval == 0 ) // first __rlen chars matched
453            __retval = size() == __sv.size() ? 0 : ( size() < __sv.size() ? -1 : 1 );
454        return __retval;
455    }
456
457    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
458    int compare(size_type __pos1, size_type __n1, basic_string_view __sv) const
459    {
460        return substr(__pos1, __n1).compare(__sv);
461    }
462
463    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
464    int compare(                       size_type __pos1, size_type __n1,
465                basic_string_view __sv, size_type __pos2, size_type __n2) const
466    {
467        return substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
468    }
469
470    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
471    int compare(const _CharT* __s) const _NOEXCEPT
472    {
473        return compare(basic_string_view(__s));
474    }
475
476    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
477    int compare(size_type __pos1, size_type __n1, const _CharT* __s) const
478    {
479        return substr(__pos1, __n1).compare(basic_string_view(__s));
480    }
481
482    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
483    int compare(size_type __pos1, size_type __n1, const _CharT* __s, size_type __n2) const
484    {
485        return substr(__pos1, __n1).compare(basic_string_view(__s, __n2));
486    }
487
488    // find
489    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
490    size_type find(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT
491    {
492        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
493        return __str_find<value_type, size_type, traits_type, npos>
494            (data(), size(), __s.data(), __pos, __s.size());
495    }
496
497    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
498    size_type find(_CharT __c, size_type __pos = 0) const _NOEXCEPT
499    {
500        return __str_find<value_type, size_type, traits_type, npos>
501            (data(), size(), __c, __pos);
502    }
503
504    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
505    size_type find(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
506    {
507        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find(): received nullptr");
508        return __str_find<value_type, size_type, traits_type, npos>
509            (data(), size(), __s, __pos, __n);
510    }
511
512    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
513    size_type find(const _CharT* __s, size_type __pos = 0) const _NOEXCEPT
514    {
515        _LIBCPP_ASSERT(__s != nullptr, "string_view::find(): received nullptr");
516        return __str_find<value_type, size_type, traits_type, npos>
517            (data(), size(), __s, __pos, traits_type::length(__s));
518    }
519
520    // rfind
521    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
522    size_type rfind(basic_string_view __s, size_type __pos = npos) const _NOEXCEPT
523    {
524        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find(): received nullptr");
525        return __str_rfind<value_type, size_type, traits_type, npos>
526            (data(), size(), __s.data(), __pos, __s.size());
527    }
528
529    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
530    size_type rfind(_CharT __c, size_type __pos = npos) const _NOEXCEPT
531    {
532        return __str_rfind<value_type, size_type, traits_type, npos>
533            (data(), size(), __c, __pos);
534    }
535
536    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
537    size_type rfind(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
538    {
539        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::rfind(): received nullptr");
540        return __str_rfind<value_type, size_type, traits_type, npos>
541            (data(), size(), __s, __pos, __n);
542    }
543
544    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
545    size_type rfind(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
546    {
547        _LIBCPP_ASSERT(__s != nullptr, "string_view::rfind(): received nullptr");
548        return __str_rfind<value_type, size_type, traits_type, npos>
549            (data(), size(), __s, __pos, traits_type::length(__s));
550    }
551
552    // find_first_of
553    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
554    size_type find_first_of(basic_string_view __s, size_type __pos = 0) const _NOEXCEPT
555    {
556        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_first_of(): received nullptr");
557        return __str_find_first_of<value_type, size_type, traits_type, npos>
558            (data(), size(), __s.data(), __pos, __s.size());
559    }
560
561    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
562    size_type find_first_of(_CharT __c, size_type __pos = 0) const _NOEXCEPT
563    { return find(__c, __pos); }
564
565    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
566    size_type find_first_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
567    {
568        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_first_of(): received nullptr");
569        return __str_find_first_of<value_type, size_type, traits_type, npos>
570            (data(), size(), __s, __pos, __n);
571    }
572
573    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
574    size_type find_first_of(const _CharT* __s, size_type __pos=0) const _NOEXCEPT
575    {
576        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_first_of(): received nullptr");
577        return __str_find_first_of<value_type, size_type, traits_type, npos>
578            (data(), size(), __s, __pos, traits_type::length(__s));
579    }
580
581    // find_last_of
582    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
583    size_type find_last_of(basic_string_view __s, size_type __pos=npos) const _NOEXCEPT
584    {
585        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_last_of(): received nullptr");
586        return __str_find_last_of<value_type, size_type, traits_type, npos>
587            (data(), size(), __s.data(), __pos, __s.size());
588    }
589
590    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
591    size_type find_last_of(_CharT __c, size_type __pos = npos) const _NOEXCEPT
592    { return rfind(__c, __pos); }
593
594    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
595    size_type find_last_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
596    {
597        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_last_of(): received nullptr");
598        return __str_find_last_of<value_type, size_type, traits_type, npos>
599            (data(), size(), __s, __pos, __n);
600    }
601
602    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
603    size_type find_last_of(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
604    {
605        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_last_of(): received nullptr");
606        return __str_find_last_of<value_type, size_type, traits_type, npos>
607            (data(), size(), __s, __pos, traits_type::length(__s));
608    }
609
610    // find_first_not_of
611    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
612    size_type find_first_not_of(basic_string_view __s, size_type __pos=0) const _NOEXCEPT
613    {
614        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_first_not_of(): received nullptr");
615        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
616            (data(), size(), __s.data(), __pos, __s.size());
617    }
618
619    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
620    size_type find_first_not_of(_CharT __c, size_type __pos=0) const _NOEXCEPT
621    {
622        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
623            (data(), size(), __c, __pos);
624    }
625
626    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
627    size_type find_first_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
628    {
629        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_first_not_of(): received nullptr");
630        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
631            (data(), size(), __s, __pos, __n);
632    }
633
634    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
635    size_type find_first_not_of(const _CharT* __s, size_type __pos=0) const _NOEXCEPT
636    {
637        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_first_not_of(): received nullptr");
638        return __str_find_first_not_of<value_type, size_type, traits_type, npos>
639            (data(), size(), __s, __pos, traits_type::length(__s));
640    }
641
642    // find_last_not_of
643    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
644    size_type find_last_not_of(basic_string_view __s, size_type __pos=npos) const _NOEXCEPT
645    {
646        _LIBCPP_ASSERT(__s.size() == 0 || __s.data() != nullptr, "string_view::find_last_not_of(): received nullptr");
647        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
648            (data(), size(), __s.data(), __pos, __s.size());
649    }
650
651    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
652    size_type find_last_not_of(_CharT __c, size_type __pos=npos) const _NOEXCEPT
653    {
654        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
655            (data(), size(), __c, __pos);
656    }
657
658    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
659    size_type find_last_not_of(const _CharT* __s, size_type __pos, size_type __n) const _NOEXCEPT
660    {
661        _LIBCPP_ASSERT(__n == 0 || __s != nullptr, "string_view::find_last_not_of(): received nullptr");
662        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
663            (data(), size(), __s, __pos, __n);
664    }
665
666    _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
667    size_type find_last_not_of(const _CharT* __s, size_type __pos=npos) const _NOEXCEPT
668    {
669        _LIBCPP_ASSERT(__s != nullptr, "string_view::find_last_not_of(): received nullptr");
670        return __str_find_last_not_of<value_type, size_type, traits_type, npos>
671            (data(), size(), __s, __pos, traits_type::length(__s));
672    }
673
674#if _LIBCPP_STD_VER > 17
675    constexpr _LIBCPP_INLINE_VISIBILITY
676    bool starts_with(basic_string_view __s) const noexcept
677    { return size() >= __s.size() && compare(0, __s.size(), __s) == 0; }
678
679    constexpr _LIBCPP_INLINE_VISIBILITY
680    bool starts_with(value_type __c) const noexcept
681    { return !empty() && _Traits::eq(front(), __c); }
682
683    constexpr _LIBCPP_INLINE_VISIBILITY
684    bool starts_with(const value_type* __s) const noexcept
685    { return starts_with(basic_string_view(__s)); }
686
687    constexpr _LIBCPP_INLINE_VISIBILITY
688    bool ends_with(basic_string_view __s) const noexcept
689    { return size() >= __s.size() && compare(size() - __s.size(), npos, __s) == 0; }
690
691    constexpr _LIBCPP_INLINE_VISIBILITY
692    bool ends_with(value_type __c) const noexcept
693    { return !empty() && _Traits::eq(back(), __c); }
694
695    constexpr _LIBCPP_INLINE_VISIBILITY
696    bool ends_with(const value_type* __s) const noexcept
697    { return ends_with(basic_string_view(__s)); }
698#endif
699
700#if _LIBCPP_STD_VER > 20
701    constexpr _LIBCPP_INLINE_VISIBILITY
702    bool contains(basic_string_view __sv) const noexcept
703    { return find(__sv) != npos; }
704
705    constexpr _LIBCPP_INLINE_VISIBILITY
706    bool contains(value_type __c) const noexcept
707    { return find(__c) != npos; }
708
709    constexpr _LIBCPP_INLINE_VISIBILITY
710    bool contains(const value_type* __s) const
711    { return find(__s) != npos; }
712#endif
713
714private:
715    const   value_type* __data;
716    size_type           __size;
717};
718
719#if _LIBCPP_STD_VER > 17
720template <class _CharT, class _Traits>
721inline constexpr bool ranges::enable_view<basic_string_view<_CharT, _Traits>> = true;
722
723template <class _CharT, class _Traits>
724inline constexpr bool ranges::enable_borrowed_range<basic_string_view<_CharT, _Traits> > = true;
725#endif // _LIBCPP_STD_VER > 17
726
727// [string.view.deduct]
728
729#if _LIBCPP_STD_VER > 17
730template <contiguous_iterator _It, sized_sentinel_for<_It> _End>
731  basic_string_view(_It, _End) -> basic_string_view<iter_value_t<_It>>;
732#endif // _LIBCPP_STD_VER > 17
733
734
735#if _LIBCPP_STD_VER > 20 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
736template <ranges::contiguous_range _Range>
737  basic_string_view(_Range) -> basic_string_view<ranges::range_value_t<_Range>>;
738#endif // _LIBCPP_STD_VER > 20 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
739
740// [string.view.comparison]
741// operator ==
742template<class _CharT, class _Traits>
743_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
744bool operator==(basic_string_view<_CharT, _Traits> __lhs,
745                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
746{
747    if ( __lhs.size() != __rhs.size()) return false;
748    return __lhs.compare(__rhs) == 0;
749}
750
751// The dummy default template parameters are used to work around a MSVC issue with mangling, see VSO-409326 for details.
752// This applies to the other sufficient overloads below for the other comparison operators.
753template<class _CharT, class _Traits, int = 1>
754_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
755bool operator==(basic_string_view<_CharT, _Traits> __lhs,
756                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
757{
758    if ( __lhs.size() != __rhs.size()) return false;
759    return __lhs.compare(__rhs) == 0;
760}
761
762template<class _CharT, class _Traits, int = 2>
763_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
764bool operator==(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
765                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
766{
767    if ( __lhs.size() != __rhs.size()) return false;
768    return __lhs.compare(__rhs) == 0;
769}
770
771
772// operator !=
773template<class _CharT, class _Traits>
774_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
775bool operator!=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
776{
777    if ( __lhs.size() != __rhs.size())
778        return true;
779    return __lhs.compare(__rhs) != 0;
780}
781
782template<class _CharT, class _Traits, int = 1>
783_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
784bool operator!=(basic_string_view<_CharT, _Traits> __lhs,
785                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
786{
787    if ( __lhs.size() != __rhs.size())
788        return true;
789    return __lhs.compare(__rhs) != 0;
790}
791
792template<class _CharT, class _Traits, int = 2>
793_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
794bool operator!=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
795                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
796{
797    if ( __lhs.size() != __rhs.size())
798        return true;
799    return __lhs.compare(__rhs) != 0;
800}
801
802
803// operator <
804template<class _CharT, class _Traits>
805_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
806bool operator<(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
807{
808    return __lhs.compare(__rhs) < 0;
809}
810
811template<class _CharT, class _Traits, int = 1>
812_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
813bool operator<(basic_string_view<_CharT, _Traits> __lhs,
814                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
815{
816    return __lhs.compare(__rhs) < 0;
817}
818
819template<class _CharT, class _Traits, int = 2>
820_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
821bool operator<(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
822                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
823{
824    return __lhs.compare(__rhs) < 0;
825}
826
827
828// operator >
829template<class _CharT, class _Traits>
830_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
831bool operator> (basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
832{
833    return __lhs.compare(__rhs) > 0;
834}
835
836template<class _CharT, class _Traits, int = 1>
837_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
838bool operator>(basic_string_view<_CharT, _Traits> __lhs,
839                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
840{
841    return __lhs.compare(__rhs) > 0;
842}
843
844template<class _CharT, class _Traits, int = 2>
845_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
846bool operator>(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
847                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
848{
849    return __lhs.compare(__rhs) > 0;
850}
851
852
853// operator <=
854template<class _CharT, class _Traits>
855_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
856bool operator<=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
857{
858    return __lhs.compare(__rhs) <= 0;
859}
860
861template<class _CharT, class _Traits, int = 1>
862_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
863bool operator<=(basic_string_view<_CharT, _Traits> __lhs,
864                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
865{
866    return __lhs.compare(__rhs) <= 0;
867}
868
869template<class _CharT, class _Traits, int = 2>
870_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
871bool operator<=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
872                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
873{
874    return __lhs.compare(__rhs) <= 0;
875}
876
877
878// operator >=
879template<class _CharT, class _Traits>
880_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
881bool operator>=(basic_string_view<_CharT, _Traits> __lhs, basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
882{
883    return __lhs.compare(__rhs) >= 0;
884}
885
886
887template<class _CharT, class _Traits, int = 1>
888_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
889bool operator>=(basic_string_view<_CharT, _Traits> __lhs,
890                typename common_type<basic_string_view<_CharT, _Traits> >::type __rhs) _NOEXCEPT
891{
892    return __lhs.compare(__rhs) >= 0;
893}
894
895template<class _CharT, class _Traits, int = 2>
896_LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
897bool operator>=(typename common_type<basic_string_view<_CharT, _Traits> >::type __lhs,
898                basic_string_view<_CharT, _Traits> __rhs) _NOEXCEPT
899{
900    return __lhs.compare(__rhs) >= 0;
901}
902
903
904template<class _CharT, class _Traits>
905basic_ostream<_CharT, _Traits>&
906operator<<(basic_ostream<_CharT, _Traits>& __os,
907           basic_string_view<_CharT, _Traits> __str);
908
909// [string.view.hash]
910template<class _CharT>
911struct _LIBCPP_TEMPLATE_VIS hash<basic_string_view<_CharT, char_traits<_CharT> > >
912    : public unary_function<basic_string_view<_CharT, char_traits<_CharT> >, size_t>
913{
914    _LIBCPP_INLINE_VISIBILITY
915    size_t operator()(const basic_string_view<_CharT, char_traits<_CharT> > __val) const _NOEXCEPT {
916        return __do_string_hash(__val.data(), __val.data() + __val.size());
917    }
918};
919
920
921#if _LIBCPP_STD_VER > 11
922inline namespace literals
923{
924  inline namespace string_view_literals
925  {
926    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
927    basic_string_view<char> operator "" sv(const char *__str, size_t __len) _NOEXCEPT
928    {
929        return basic_string_view<char> (__str, __len);
930    }
931
932#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
933    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
934    basic_string_view<wchar_t> operator "" sv(const wchar_t *__str, size_t __len) _NOEXCEPT
935    {
936        return basic_string_view<wchar_t> (__str, __len);
937    }
938#endif
939
940#ifndef _LIBCPP_HAS_NO_CHAR8_T
941    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
942    basic_string_view<char8_t> operator "" sv(const char8_t *__str, size_t __len) _NOEXCEPT
943    {
944        return basic_string_view<char8_t> (__str, __len);
945    }
946#endif
947
948    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
949    basic_string_view<char16_t> operator "" sv(const char16_t *__str, size_t __len) _NOEXCEPT
950    {
951        return basic_string_view<char16_t> (__str, __len);
952    }
953
954    inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
955    basic_string_view<char32_t> operator "" sv(const char32_t *__str, size_t __len) _NOEXCEPT
956    {
957        return basic_string_view<char32_t> (__str, __len);
958    }
959  } // namespace string_view_literals
960} // namespace literals
961#endif
962_LIBCPP_END_NAMESPACE_STD
963
964_LIBCPP_POP_MACROS
965
966#endif // _LIBCPP_STRING_VIEW
967