source: Daodan/MSYS2/mingw32/include/c++/11.2.0/string_view@ 1181

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[1166]1// Components for manipulating non-owning sequences of characters -*- C++ -*-
2
3// Copyright (C) 2013-2021 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file include/string_view
26 * This is a Standard C++ Library header.
27 */
28
29//
30// N3762 basic_string_view library
31//
32
33#ifndef _GLIBCXX_STRING_VIEW
34#define _GLIBCXX_STRING_VIEW 1
35
36#pragma GCC system_header
37
38#if __cplusplus >= 201703L
39
40#include <iosfwd>
41#include <bits/char_traits.h>
42#include <bits/functional_hash.h>
43#include <bits/range_access.h>
44#include <bits/ostream_insert.h>
45#include <ext/numeric_traits.h>
46
47#if __cplusplus >= 202002L
48# include <bits/ranges_base.h>
49#endif
50
51namespace std _GLIBCXX_VISIBILITY(default)
52{
53_GLIBCXX_BEGIN_NAMESPACE_VERSION
54
55# define __cpp_lib_string_view 201803L
56#if __cplusplus > 201703L
57# define __cpp_lib_constexpr_string_view 201811L
58#endif
59
60 // Helper for basic_string and basic_string_view members.
61 constexpr size_t
62 __sv_check(size_t __size, size_t __pos, const char* __s)
63 {
64 if (__pos > __size)
65 __throw_out_of_range_fmt(__N("%s: __pos (which is %zu) > __size "
66 "(which is %zu)"), __s, __pos, __size);
67 return __pos;
68 }
69
70 // Helper for basic_string members.
71 // NB: __sv_limit doesn't check for a bad __pos value.
72 constexpr size_t
73 __sv_limit(size_t __size, size_t __pos, size_t __off) noexcept
74 {
75 const bool __testoff = __off < __size - __pos;
76 return __testoff ? __off : __size - __pos;
77 }
78
79 /**
80 * @class basic_string_view <string_view>
81 * @brief A non-owning reference to a string.
82 *
83 * @ingroup strings
84 * @ingroup sequences
85 *
86 * @tparam _CharT Type of character
87 * @tparam _Traits Traits for character type, defaults to
88 * char_traits<_CharT>.
89 *
90 * A basic_string_view looks like this:
91 *
92 * @code
93 * _CharT* _M_str
94 * size_t _M_len
95 * @endcode
96 */
97 template<typename _CharT, typename _Traits = std::char_traits<_CharT>>
98 class basic_string_view
99 {
100 static_assert(!is_array_v<_CharT>);
101 static_assert(is_trivial_v<_CharT> && is_standard_layout_v<_CharT>);
102 static_assert(is_same_v<_CharT, typename _Traits::char_type>);
103
104 public:
105
106 // types
107 using traits_type = _Traits;
108 using value_type = _CharT;
109 using pointer = value_type*;
110 using const_pointer = const value_type*;
111 using reference = value_type&;
112 using const_reference = const value_type&;
113 using const_iterator = const value_type*;
114 using iterator = const_iterator;
115 using const_reverse_iterator = std::reverse_iterator<const_iterator>;
116 using reverse_iterator = const_reverse_iterator;
117 using size_type = size_t;
118 using difference_type = ptrdiff_t;
119 static constexpr size_type npos = size_type(-1);
120
121 // [string.view.cons], construction and assignment
122
123 constexpr
124 basic_string_view() noexcept
125 : _M_len{0}, _M_str{nullptr}
126 { }
127
128 constexpr basic_string_view(const basic_string_view&) noexcept = default;
129
130 __attribute__((__nonnull__)) constexpr
131 basic_string_view(const _CharT* __str) noexcept
132 : _M_len{traits_type::length(__str)},
133 _M_str{__str}
134 { }
135
136 constexpr
137 basic_string_view(const _CharT* __str, size_type __len) noexcept
138 : _M_len{__len}, _M_str{__str}
139 { }
140
141#if __cplusplus >= 202002L && __cpp_lib_concepts
142 template<contiguous_iterator _It, sized_sentinel_for<_It> _End>
143 requires same_as<iter_value_t<_It>, _CharT>
144 && (!convertible_to<_End, size_type>)
145 constexpr
146 basic_string_view(_It __first, _End __last)
147 : _M_len(__last - __first), _M_str(std::to_address(__first))
148 { }
149
150#if __cplusplus > 202002L
151 template<typename _Range, typename _DRange = remove_cvref_t<_Range>>
152 requires (!is_same_v<_DRange, basic_string_view>)
153 && ranges::contiguous_range<_Range>
154 && ranges::sized_range<_Range>
155 && is_same_v<ranges::range_value_t<_Range>, _CharT>
156 && (!is_convertible_v<_Range, const _CharT*>)
157 && (!requires (_DRange& __d) {
158 __d.operator ::std::basic_string_view<_CharT, _Traits>();
159 })
160 && (!requires { typename _DRange::traits_type; }
161 || is_same_v<typename _DRange::traits_type, _Traits>)
162 constexpr
163 basic_string_view(_Range&& __r)
164 noexcept(noexcept(ranges::size(__r)) && noexcept(ranges::data(__r)))
165 : _M_len(ranges::size(__r)), _M_str(ranges::data(__r))
166 { }
167#endif // C++23
168#endif // C++20
169
170 constexpr basic_string_view&
171 operator=(const basic_string_view&) noexcept = default;
172
173 // [string.view.iterators], iterator support
174
175 constexpr const_iterator
176 begin() const noexcept
177 { return this->_M_str; }
178
179 constexpr const_iterator
180 end() const noexcept
181 { return this->_M_str + this->_M_len; }
182
183 constexpr const_iterator
184 cbegin() const noexcept
185 { return this->_M_str; }
186
187 constexpr const_iterator
188 cend() const noexcept
189 { return this->_M_str + this->_M_len; }
190
191 constexpr const_reverse_iterator
192 rbegin() const noexcept
193 { return const_reverse_iterator(this->end()); }
194
195 constexpr const_reverse_iterator
196 rend() const noexcept
197 { return const_reverse_iterator(this->begin()); }
198
199 constexpr const_reverse_iterator
200 crbegin() const noexcept
201 { return const_reverse_iterator(this->end()); }
202
203 constexpr const_reverse_iterator
204 crend() const noexcept
205 { return const_reverse_iterator(this->begin()); }
206
207 // [string.view.capacity], capacity
208
209 constexpr size_type
210 size() const noexcept
211 { return this->_M_len; }
212
213 constexpr size_type
214 length() const noexcept
215 { return _M_len; }
216
217 constexpr size_type
218 max_size() const noexcept
219 {
220 return (npos - sizeof(size_type) - sizeof(void*))
221 / sizeof(value_type) / 4;
222 }
223
224 [[nodiscard]] constexpr bool
225 empty() const noexcept
226 { return this->_M_len == 0; }
227
228 // [string.view.access], element access
229
230 constexpr const_reference
231 operator[](size_type __pos) const noexcept
232 {
233 __glibcxx_assert(__pos < this->_M_len);
234 return *(this->_M_str + __pos);
235 }
236
237 constexpr const_reference
238 at(size_type __pos) const
239 {
240 if (__pos >= _M_len)
241 __throw_out_of_range_fmt(__N("basic_string_view::at: __pos "
242 "(which is %zu) >= this->size() "
243 "(which is %zu)"), __pos, this->size());
244 return *(this->_M_str + __pos);
245 }
246
247 constexpr const_reference
248 front() const noexcept
249 {
250 __glibcxx_assert(this->_M_len > 0);
251 return *this->_M_str;
252 }
253
254 constexpr const_reference
255 back() const noexcept
256 {
257 __glibcxx_assert(this->_M_len > 0);
258 return *(this->_M_str + this->_M_len - 1);
259 }
260
261 constexpr const_pointer
262 data() const noexcept
263 { return this->_M_str; }
264
265 // [string.view.modifiers], modifiers:
266
267 constexpr void
268 remove_prefix(size_type __n) noexcept
269 {
270 __glibcxx_assert(this->_M_len >= __n);
271 this->_M_str += __n;
272 this->_M_len -= __n;
273 }
274
275 constexpr void
276 remove_suffix(size_type __n) noexcept
277 { this->_M_len -= __n; }
278
279 constexpr void
280 swap(basic_string_view& __sv) noexcept
281 {
282 auto __tmp = *this;
283 *this = __sv;
284 __sv = __tmp;
285 }
286
287 // [string.view.ops], string operations:
288
289 _GLIBCXX20_CONSTEXPR
290 size_type
291 copy(_CharT* __str, size_type __n, size_type __pos = 0) const
292 {
293 __glibcxx_requires_string_len(__str, __n);
294 __pos = std::__sv_check(size(), __pos, "basic_string_view::copy");
295 const size_type __rlen = std::min(__n, _M_len - __pos);
296 // _GLIBCXX_RESOLVE_LIB_DEFECTS
297 // 2777. basic_string_view::copy should use char_traits::copy
298 traits_type::copy(__str, data() + __pos, __rlen);
299 return __rlen;
300 }
301
302 constexpr basic_string_view
303 substr(size_type __pos = 0, size_type __n = npos) const noexcept(false)
304 {
305 __pos = std::__sv_check(size(), __pos, "basic_string_view::substr");
306 const size_type __rlen = std::min(__n, _M_len - __pos);
307 return basic_string_view{_M_str + __pos, __rlen};
308 }
309
310 constexpr int
311 compare(basic_string_view __str) const noexcept
312 {
313 const size_type __rlen = std::min(this->_M_len, __str._M_len);
314 int __ret = traits_type::compare(this->_M_str, __str._M_str, __rlen);
315 if (__ret == 0)
316 __ret = _S_compare(this->_M_len, __str._M_len);
317 return __ret;
318 }
319
320 constexpr int
321 compare(size_type __pos1, size_type __n1, basic_string_view __str) const
322 { return this->substr(__pos1, __n1).compare(__str); }
323
324 constexpr int
325 compare(size_type __pos1, size_type __n1,
326 basic_string_view __str, size_type __pos2, size_type __n2) const
327 {
328 return this->substr(__pos1, __n1).compare(__str.substr(__pos2, __n2));
329 }
330
331 __attribute__((__nonnull__)) constexpr int
332 compare(const _CharT* __str) const noexcept
333 { return this->compare(basic_string_view{__str}); }
334
335 __attribute__((__nonnull__)) constexpr int
336 compare(size_type __pos1, size_type __n1, const _CharT* __str) const
337 { return this->substr(__pos1, __n1).compare(basic_string_view{__str}); }
338
339 constexpr int
340 compare(size_type __pos1, size_type __n1,
341 const _CharT* __str, size_type __n2) const noexcept(false)
342 {
343 return this->substr(__pos1, __n1)
344 .compare(basic_string_view(__str, __n2));
345 }
346
347#if __cplusplus > 201703L
348#define __cpp_lib_starts_ends_with 201711L
349 constexpr bool
350 starts_with(basic_string_view __x) const noexcept
351 { return this->substr(0, __x.size()) == __x; }
352
353 constexpr bool
354 starts_with(_CharT __x) const noexcept
355 { return !this->empty() && traits_type::eq(this->front(), __x); }
356
357 constexpr bool
358 starts_with(const _CharT* __x) const noexcept
359 { return this->starts_with(basic_string_view(__x)); }
360
361 constexpr bool
362 ends_with(basic_string_view __x) const noexcept
363 {
364 const auto __len = this->size();
365 const auto __xlen = __x.size();
366 return __len >= __xlen
367 && traits_type::compare(end() - __xlen, __x.data(), __xlen) == 0;
368 }
369
370 constexpr bool
371 ends_with(_CharT __x) const noexcept
372 { return !this->empty() && traits_type::eq(this->back(), __x); }
373
374 constexpr bool
375 ends_with(const _CharT* __x) const noexcept
376 { return this->ends_with(basic_string_view(__x)); }
377#endif // C++20
378
379#if __cplusplus > 202002L
380#define __cpp_lib_string_contains 202011L
381 constexpr bool
382 contains(basic_string_view __x) const noexcept
383 { return this->find(__x) != npos; }
384
385 constexpr bool
386 contains(_CharT __x) const noexcept
387 { return this->find(__x) != npos; }
388
389 constexpr bool
390 contains(const _CharT* __x) const noexcept
391 { return this->find(__x) != npos; }
392#endif // C++23
393
394 // [string.view.find], searching
395
396 constexpr size_type
397 find(basic_string_view __str, size_type __pos = 0) const noexcept
398 { return this->find(__str._M_str, __pos, __str._M_len); }
399
400 constexpr size_type
401 find(_CharT __c, size_type __pos = 0) const noexcept;
402
403 constexpr size_type
404 find(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
405
406 __attribute__((__nonnull__)) constexpr size_type
407 find(const _CharT* __str, size_type __pos = 0) const noexcept
408 { return this->find(__str, __pos, traits_type::length(__str)); }
409
410 constexpr size_type
411 rfind(basic_string_view __str, size_type __pos = npos) const noexcept
412 { return this->rfind(__str._M_str, __pos, __str._M_len); }
413
414 constexpr size_type
415 rfind(_CharT __c, size_type __pos = npos) const noexcept;
416
417 constexpr size_type
418 rfind(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
419
420 __attribute__((__nonnull__)) constexpr size_type
421 rfind(const _CharT* __str, size_type __pos = npos) const noexcept
422 { return this->rfind(__str, __pos, traits_type::length(__str)); }
423
424 constexpr size_type
425 find_first_of(basic_string_view __str, size_type __pos = 0) const noexcept
426 { return this->find_first_of(__str._M_str, __pos, __str._M_len); }
427
428 constexpr size_type
429 find_first_of(_CharT __c, size_type __pos = 0) const noexcept
430 { return this->find(__c, __pos); }
431
432 constexpr size_type
433 find_first_of(const _CharT* __str, size_type __pos,
434 size_type __n) const noexcept;
435
436 __attribute__((__nonnull__)) constexpr size_type
437 find_first_of(const _CharT* __str, size_type __pos = 0) const noexcept
438 { return this->find_first_of(__str, __pos, traits_type::length(__str)); }
439
440 constexpr size_type
441 find_last_of(basic_string_view __str,
442 size_type __pos = npos) const noexcept
443 { return this->find_last_of(__str._M_str, __pos, __str._M_len); }
444
445 constexpr size_type
446 find_last_of(_CharT __c, size_type __pos=npos) const noexcept
447 { return this->rfind(__c, __pos); }
448
449 constexpr size_type
450 find_last_of(const _CharT* __str, size_type __pos,
451 size_type __n) const noexcept;
452
453 __attribute__((__nonnull__)) constexpr size_type
454 find_last_of(const _CharT* __str, size_type __pos = npos) const noexcept
455 { return this->find_last_of(__str, __pos, traits_type::length(__str)); }
456
457 constexpr size_type
458 find_first_not_of(basic_string_view __str,
459 size_type __pos = 0) const noexcept
460 { return this->find_first_not_of(__str._M_str, __pos, __str._M_len); }
461
462 constexpr size_type
463 find_first_not_of(_CharT __c, size_type __pos = 0) const noexcept;
464
465 constexpr size_type
466 find_first_not_of(const _CharT* __str,
467 size_type __pos, size_type __n) const noexcept;
468
469 __attribute__((__nonnull__)) constexpr size_type
470 find_first_not_of(const _CharT* __str, size_type __pos = 0) const noexcept
471 {
472 return this->find_first_not_of(__str, __pos,
473 traits_type::length(__str));
474 }
475
476 constexpr size_type
477 find_last_not_of(basic_string_view __str,
478 size_type __pos = npos) const noexcept
479 { return this->find_last_not_of(__str._M_str, __pos, __str._M_len); }
480
481 constexpr size_type
482 find_last_not_of(_CharT __c, size_type __pos = npos) const noexcept;
483
484 constexpr size_type
485 find_last_not_of(const _CharT* __str,
486 size_type __pos, size_type __n) const noexcept;
487
488 __attribute__((__nonnull__)) constexpr size_type
489 find_last_not_of(const _CharT* __str,
490 size_type __pos = npos) const noexcept
491 {
492 return this->find_last_not_of(__str, __pos,
493 traits_type::length(__str));
494 }
495
496 private:
497
498 static constexpr int
499 _S_compare(size_type __n1, size_type __n2) noexcept
500 {
501 using __limits = __gnu_cxx::__int_traits<int>;
502 const difference_type __diff = __n1 - __n2;
503 if (__diff > __limits::__max)
504 return __limits::__max;
505 if (__diff < __limits::__min)
506 return __limits::__min;
507 return static_cast<int>(__diff);
508 }
509
510 size_t _M_len;
511 const _CharT* _M_str;
512 };
513
514#if __cplusplus > 201703L && __cpp_lib_concepts && __cpp_deduction_guides
515 template<contiguous_iterator _It, sized_sentinel_for<_It> _End>
516 basic_string_view(_It, _End) -> basic_string_view<iter_value_t<_It>>;
517
518#if __cplusplus > 202002L
519 template<ranges::contiguous_range _Range>
520 basic_string_view(_Range&&)
521 -> basic_string_view<ranges::range_value_t<_Range>>;
522#endif
523#endif
524
525 // [string.view.comparison], non-member basic_string_view comparison function
526
527 // Several of these functions use type_identity_t to create a non-deduced
528 // context, so that only one argument participates in template argument
529 // deduction and the other argument gets implicitly converted to the deduced
530 // type (see N3766).
531
532 template<typename _CharT, typename _Traits>
533 constexpr bool
534 operator==(basic_string_view<_CharT, _Traits> __x,
535 basic_string_view<_CharT, _Traits> __y) noexcept
536 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
537
538 template<typename _CharT, typename _Traits>
539 constexpr bool
540 operator==(basic_string_view<_CharT, _Traits> __x,
541 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
542 noexcept
543 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
544
545#if __cpp_lib_three_way_comparison
546 template<typename _CharT, typename _Traits>
547 constexpr auto
548 operator<=>(basic_string_view<_CharT, _Traits> __x,
549 basic_string_view<_CharT, _Traits> __y) noexcept
550 -> decltype(__detail::__char_traits_cmp_cat<_Traits>(0))
551 { return __detail::__char_traits_cmp_cat<_Traits>(__x.compare(__y)); }
552
553 template<typename _CharT, typename _Traits>
554 constexpr auto
555 operator<=>(basic_string_view<_CharT, _Traits> __x,
556 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
557 noexcept
558 -> decltype(__detail::__char_traits_cmp_cat<_Traits>(0))
559 { return __detail::__char_traits_cmp_cat<_Traits>(__x.compare(__y)); }
560#else
561 template<typename _CharT, typename _Traits>
562 constexpr bool
563 operator==(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
564 basic_string_view<_CharT, _Traits> __y) noexcept
565 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
566
567 template<typename _CharT, typename _Traits>
568 constexpr bool
569 operator!=(basic_string_view<_CharT, _Traits> __x,
570 basic_string_view<_CharT, _Traits> __y) noexcept
571 { return !(__x == __y); }
572
573 template<typename _CharT, typename _Traits>
574 constexpr bool
575 operator!=(basic_string_view<_CharT, _Traits> __x,
576 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
577 noexcept
578 { return !(__x == __y); }
579
580 template<typename _CharT, typename _Traits>
581 constexpr bool
582 operator!=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
583 basic_string_view<_CharT, _Traits> __y) noexcept
584 { return !(__x == __y); }
585
586 template<typename _CharT, typename _Traits>
587 constexpr bool
588 operator< (basic_string_view<_CharT, _Traits> __x,
589 basic_string_view<_CharT, _Traits> __y) noexcept
590 { return __x.compare(__y) < 0; }
591
592 template<typename _CharT, typename _Traits>
593 constexpr bool
594 operator< (basic_string_view<_CharT, _Traits> __x,
595 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
596 noexcept
597 { return __x.compare(__y) < 0; }
598
599 template<typename _CharT, typename _Traits>
600 constexpr bool
601 operator< (__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
602 basic_string_view<_CharT, _Traits> __y) noexcept
603 { return __x.compare(__y) < 0; }
604
605 template<typename _CharT, typename _Traits>
606 constexpr bool
607 operator> (basic_string_view<_CharT, _Traits> __x,
608 basic_string_view<_CharT, _Traits> __y) noexcept
609 { return __x.compare(__y) > 0; }
610
611 template<typename _CharT, typename _Traits>
612 constexpr bool
613 operator> (basic_string_view<_CharT, _Traits> __x,
614 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
615 noexcept
616 { return __x.compare(__y) > 0; }
617
618 template<typename _CharT, typename _Traits>
619 constexpr bool
620 operator> (__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
621 basic_string_view<_CharT, _Traits> __y) noexcept
622 { return __x.compare(__y) > 0; }
623
624 template<typename _CharT, typename _Traits>
625 constexpr bool
626 operator<=(basic_string_view<_CharT, _Traits> __x,
627 basic_string_view<_CharT, _Traits> __y) noexcept
628 { return __x.compare(__y) <= 0; }
629
630 template<typename _CharT, typename _Traits>
631 constexpr bool
632 operator<=(basic_string_view<_CharT, _Traits> __x,
633 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
634 noexcept
635 { return __x.compare(__y) <= 0; }
636
637 template<typename _CharT, typename _Traits>
638 constexpr bool
639 operator<=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
640 basic_string_view<_CharT, _Traits> __y) noexcept
641 { return __x.compare(__y) <= 0; }
642
643 template<typename _CharT, typename _Traits>
644 constexpr bool
645 operator>=(basic_string_view<_CharT, _Traits> __x,
646 basic_string_view<_CharT, _Traits> __y) noexcept
647 { return __x.compare(__y) >= 0; }
648
649 template<typename _CharT, typename _Traits>
650 constexpr bool
651 operator>=(basic_string_view<_CharT, _Traits> __x,
652 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
653 noexcept
654 { return __x.compare(__y) >= 0; }
655
656 template<typename _CharT, typename _Traits>
657 constexpr bool
658 operator>=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
659 basic_string_view<_CharT, _Traits> __y) noexcept
660 { return __x.compare(__y) >= 0; }
661#endif // three-way comparison
662
663 // [string.view.io], Inserters and extractors
664 template<typename _CharT, typename _Traits>
665 inline basic_ostream<_CharT, _Traits>&
666 operator<<(basic_ostream<_CharT, _Traits>& __os,
667 basic_string_view<_CharT,_Traits> __str)
668 { return __ostream_insert(__os, __str.data(), __str.size()); }
669
670
671 // basic_string_view typedef names
672
673 using string_view = basic_string_view<char>;
674#ifdef _GLIBCXX_USE_WCHAR_T
675 using wstring_view = basic_string_view<wchar_t>;
676#endif
677#ifdef _GLIBCXX_USE_CHAR8_T
678 using u8string_view = basic_string_view<char8_t>;
679#endif
680 using u16string_view = basic_string_view<char16_t>;
681 using u32string_view = basic_string_view<char32_t>;
682
683 // [string.view.hash], hash support:
684
685 template<typename _Tp>
686 struct hash;
687
688 template<>
689 struct hash<string_view>
690 : public __hash_base<size_t, string_view>
691 {
692 size_t
693 operator()(const string_view& __str) const noexcept
694 { return std::_Hash_impl::hash(__str.data(), __str.length()); }
695 };
696
697 template<>
698 struct __is_fast_hash<hash<string_view>> : std::false_type
699 { };
700
701#ifdef _GLIBCXX_USE_WCHAR_T
702 template<>
703 struct hash<wstring_view>
704 : public __hash_base<size_t, wstring_view>
705 {
706 size_t
707 operator()(const wstring_view& __s) const noexcept
708 { return std::_Hash_impl::hash(__s.data(),
709 __s.length() * sizeof(wchar_t)); }
710 };
711
712 template<>
713 struct __is_fast_hash<hash<wstring_view>> : std::false_type
714 { };
715#endif
716
717#ifdef _GLIBCXX_USE_CHAR8_T
718 template<>
719 struct hash<u8string_view>
720 : public __hash_base<size_t, u8string_view>
721 {
722 size_t
723 operator()(const u8string_view& __str) const noexcept
724 { return std::_Hash_impl::hash(__str.data(), __str.length()); }
725 };
726
727 template<>
728 struct __is_fast_hash<hash<u8string_view>> : std::false_type
729 { };
730#endif
731
732 template<>
733 struct hash<u16string_view>
734 : public __hash_base<size_t, u16string_view>
735 {
736 size_t
737 operator()(const u16string_view& __s) const noexcept
738 { return std::_Hash_impl::hash(__s.data(),
739 __s.length() * sizeof(char16_t)); }
740 };
741
742 template<>
743 struct __is_fast_hash<hash<u16string_view>> : std::false_type
744 { };
745
746 template<>
747 struct hash<u32string_view>
748 : public __hash_base<size_t, u32string_view>
749 {
750 size_t
751 operator()(const u32string_view& __s) const noexcept
752 { return std::_Hash_impl::hash(__s.data(),
753 __s.length() * sizeof(char32_t)); }
754 };
755
756 template<>
757 struct __is_fast_hash<hash<u32string_view>> : std::false_type
758 { };
759
760 inline namespace literals
761 {
762 inline namespace string_view_literals
763 {
764#pragma GCC diagnostic push
765#pragma GCC diagnostic ignored "-Wliteral-suffix"
766 inline constexpr basic_string_view<char>
767 operator""sv(const char* __str, size_t __len) noexcept
768 { return basic_string_view<char>{__str, __len}; }
769
770#ifdef _GLIBCXX_USE_WCHAR_T
771 inline constexpr basic_string_view<wchar_t>
772 operator""sv(const wchar_t* __str, size_t __len) noexcept
773 { return basic_string_view<wchar_t>{__str, __len}; }
774#endif
775
776#ifdef _GLIBCXX_USE_CHAR8_T
777 inline constexpr basic_string_view<char8_t>
778 operator""sv(const char8_t* __str, size_t __len) noexcept
779 { return basic_string_view<char8_t>{__str, __len}; }
780#endif
781
782 inline constexpr basic_string_view<char16_t>
783 operator""sv(const char16_t* __str, size_t __len) noexcept
784 { return basic_string_view<char16_t>{__str, __len}; }
785
786 inline constexpr basic_string_view<char32_t>
787 operator""sv(const char32_t* __str, size_t __len) noexcept
788 { return basic_string_view<char32_t>{__str, __len}; }
789
790#pragma GCC diagnostic pop
791 } // namespace string_literals
792 } // namespace literals
793
794#if __cpp_lib_concepts
795 namespace ranges
796 {
797 // Opt-in to borrowed_range concept
798 template<typename _CharT, typename _Traits>
799 inline constexpr bool
800 enable_borrowed_range<basic_string_view<_CharT, _Traits>> = true;
801
802 // Opt-in to view concept
803 template<typename _CharT, typename _Traits>
804 inline constexpr bool
805 enable_view<basic_string_view<_CharT, _Traits>> = true;
806 }
807#endif
808_GLIBCXX_END_NAMESPACE_VERSION
809} // namespace std
810
811#include <bits/string_view.tcc>
812
813#endif // __cplusplus <= 201402L
814
815#endif // _GLIBCXX_EXPERIMENTAL_STRING_VIEW
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