1// Components for manipulating non-owning sequences of characters -*- C++ -*-
2
3// Copyright (C) 2013-2022 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/functexcept.h>
43#include <bits/functional_hash.h>
44#include <bits/range_access.h>
45#include <bits/ostream_insert.h>
46#include <bits/stl_algobase.h>
47#include <ext/numeric_traits.h>
48
49#if __cplusplus >= 202002L
50# include <bits/ranges_base.h>
51#endif
52
53namespace std _GLIBCXX_VISIBILITY(default)
54{
55_GLIBCXX_BEGIN_NAMESPACE_VERSION
56
57# define __cpp_lib_string_view 201803L
58#if __cplusplus > 201703L
59# define __cpp_lib_constexpr_string_view 201811L
60#endif
61
62 // Helper for basic_string and basic_string_view members.
63 constexpr size_t
64 __sv_check(size_t __size, size_t __pos, const char* __s)
65 {
66 if (__pos > __size)
67 __throw_out_of_range_fmt(__N("%s: __pos (which is %zu) > __size "
68 "(which is %zu)"), __s, __pos, __size);
69 return __pos;
70 }
71
72 // Helper for basic_string members.
73 // NB: __sv_limit doesn't check for a bad __pos value.
74 constexpr size_t
75 __sv_limit(size_t __size, size_t __pos, size_t __off) noexcept
76 {
77 const bool __testoff = __off < __size - __pos;
78 return __testoff ? __off : __size - __pos;
79 }
80
81 /**
82 * @class basic_string_view <string_view>
83 * @brief A non-owning reference to a string.
84 *
85 * @ingroup strings
86 * @ingroup sequences
87 *
88 * @tparam _CharT Type of character
89 * @tparam _Traits Traits for character type, defaults to
90 * char_traits<_CharT>.
91 *
92 * A basic_string_view looks like this:
93 *
94 * @code
95 * _CharT* _M_str
96 * size_t _M_len
97 * @endcode
98 */
99 template<typename _CharT, typename _Traits = std::char_traits<_CharT>>
100 class basic_string_view
101 {
102 static_assert(!is_array_v<_CharT>);
103 static_assert(is_trivial_v<_CharT> && is_standard_layout_v<_CharT>);
104 static_assert(is_same_v<_CharT, typename _Traits::char_type>);
105
106 public:
107
108 // types
109 using traits_type = _Traits;
110 using value_type = _CharT;
111 using pointer = value_type*;
112 using const_pointer = const value_type*;
113 using reference = value_type&;
114 using const_reference = const value_type&;
115 using const_iterator = const value_type*;
116 using iterator = const_iterator;
117 using const_reverse_iterator = std::reverse_iterator<const_iterator>;
118 using reverse_iterator = const_reverse_iterator;
119 using size_type = size_t;
120 using difference_type = ptrdiff_t;
121 static constexpr size_type npos = size_type(-1);
122
123 // [string.view.cons], construction and assignment
124
125 constexpr
126 basic_string_view() noexcept
127 : _M_len{0}, _M_str{nullptr}
128 { }
129
130 constexpr basic_string_view(const basic_string_view&) noexcept = default;
131
132 __attribute__((__nonnull__)) constexpr
133 basic_string_view(const _CharT* __str) noexcept
134 : _M_len{traits_type::length(__str)},
135 _M_str{__str}
136 { }
137
138 constexpr
139 basic_string_view(const _CharT* __str, size_type __len) noexcept
140 : _M_len{__len}, _M_str{__str}
141 { }
142
143#if __cplusplus >= 202002L && __cpp_lib_concepts
144 template<contiguous_iterator _It, sized_sentinel_for<_It> _End>
145 requires same_as<iter_value_t<_It>, _CharT>
146 && (!convertible_to<_End, size_type>)
147 constexpr
148 basic_string_view(_It __first, _End __last)
149 noexcept(noexcept(__last - __first))
150 : _M_len(__last - __first), _M_str(std::to_address(__first))
151 { }
152
153#if __cplusplus > 202002L
154 template<typename _Range, typename _DRange = remove_cvref_t<_Range>>
155 requires (!is_same_v<_DRange, basic_string_view>)
156 && ranges::contiguous_range<_Range>
157 && ranges::sized_range<_Range>
158 && is_same_v<ranges::range_value_t<_Range>, _CharT>
159 && (!is_convertible_v<_Range, const _CharT*>)
160 && (!requires (_DRange& __d) {
161 __d.operator ::std::basic_string_view<_CharT, _Traits>();
162 })
163 && (!requires { typename _DRange::traits_type; }
164 || is_same_v<typename _DRange::traits_type, _Traits>)
165 constexpr explicit
166 basic_string_view(_Range&& __r)
167 noexcept(noexcept(ranges::size(__r)) && noexcept(ranges::data(__r)))
168 : _M_len(ranges::size(__r)), _M_str(ranges::data(__r))
169 { }
170
171 basic_string_view(nullptr_t) = delete;
172#endif // C++23
173#endif // C++20
174
175
176 constexpr basic_string_view&
177 operator=(const basic_string_view&) noexcept = default;
178
179 // [string.view.iterators], iterator support
180
181 constexpr const_iterator
182 begin() const noexcept
183 { return this->_M_str; }
184
185 constexpr const_iterator
186 end() const noexcept
187 { return this->_M_str + this->_M_len; }
188
189 constexpr const_iterator
190 cbegin() const noexcept
191 { return this->_M_str; }
192
193 constexpr const_iterator
194 cend() const noexcept
195 { return this->_M_str + this->_M_len; }
196
197 constexpr const_reverse_iterator
198 rbegin() const noexcept
199 { return const_reverse_iterator(this->end()); }
200
201 constexpr const_reverse_iterator
202 rend() const noexcept
203 { return const_reverse_iterator(this->begin()); }
204
205 constexpr const_reverse_iterator
206 crbegin() const noexcept
207 { return const_reverse_iterator(this->end()); }
208
209 constexpr const_reverse_iterator
210 crend() const noexcept
211 { return const_reverse_iterator(this->begin()); }
212
213 // [string.view.capacity], capacity
214
215 constexpr size_type
216 size() const noexcept
217 { return this->_M_len; }
218
219 constexpr size_type
220 length() const noexcept
221 { return _M_len; }
222
223 constexpr size_type
224 max_size() const noexcept
225 {
226 return (npos - sizeof(size_type) - sizeof(void*))
227 / sizeof(value_type) / 4;
228 }
229
230 [[nodiscard]] constexpr bool
231 empty() const noexcept
232 { return this->_M_len == 0; }
233
234 // [string.view.access], element access
235
236 constexpr const_reference
237 operator[](size_type __pos) const noexcept
238 {
239 __glibcxx_assert(__pos < this->_M_len);
240 return *(this->_M_str + __pos);
241 }
242
243 constexpr const_reference
244 at(size_type __pos) const
245 {
246 if (__pos >= _M_len)
247 __throw_out_of_range_fmt(__N("basic_string_view::at: __pos "
248 "(which is %zu) >= this->size() "
249 "(which is %zu)"), __pos, this->size());
250 return *(this->_M_str + __pos);
251 }
252
253 constexpr const_reference
254 front() const noexcept
255 {
256 __glibcxx_assert(this->_M_len > 0);
257 return *this->_M_str;
258 }
259
260 constexpr const_reference
261 back() const noexcept
262 {
263 __glibcxx_assert(this->_M_len > 0);
264 return *(this->_M_str + this->_M_len - 1);
265 }
266
267 constexpr const_pointer
268 data() const noexcept
269 { return this->_M_str; }
270
271 // [string.view.modifiers], modifiers:
272
273 constexpr void
274 remove_prefix(size_type __n) noexcept
275 {
276 __glibcxx_assert(this->_M_len >= __n);
277 this->_M_str += __n;
278 this->_M_len -= __n;
279 }
280
281 constexpr void
282 remove_suffix(size_type __n) noexcept
283 { this->_M_len -= __n; }
284
285 constexpr void
286 swap(basic_string_view& __sv) noexcept
287 {
288 auto __tmp = *this;
289 *this = __sv;
290 __sv = __tmp;
291 }
292
293 // [string.view.ops], string operations:
294
295 _GLIBCXX20_CONSTEXPR
296 size_type
297 copy(_CharT* __str, size_type __n, size_type __pos = 0) const
298 {
299 __glibcxx_requires_string_len(__str, __n);
300 __pos = std::__sv_check(size: size(), __pos, s: "basic_string_view::copy");
301 const size_type __rlen = std::min(a: __n, b: _M_len - __pos);
302 // _GLIBCXX_RESOLVE_LIB_DEFECTS
303 // 2777. basic_string_view::copy should use char_traits::copy
304 traits_type::copy(__str, data() + __pos, __rlen);
305 return __rlen;
306 }
307
308 constexpr basic_string_view
309 substr(size_type __pos = 0, size_type __n = npos) const noexcept(false)
310 {
311 __pos = std::__sv_check(size: size(), __pos, s: "basic_string_view::substr");
312 const size_type __rlen = std::min(a: __n, b: _M_len - __pos);
313 return basic_string_view{_M_str + __pos, __rlen};
314 }
315
316 constexpr int
317 compare(basic_string_view __str) const noexcept
318 {
319 const size_type __rlen = std::min(this->_M_len, __str._M_len);
320 int __ret = traits_type::compare(this->_M_str, __str._M_str, __rlen);
321 if (__ret == 0)
322 __ret = _S_compare(n1: this->_M_len, n2: __str._M_len);
323 return __ret;
324 }
325
326 constexpr int
327 compare(size_type __pos1, size_type __n1, basic_string_view __str) const
328 { return this->substr(__pos1, __n1).compare(__str); }
329
330 constexpr int
331 compare(size_type __pos1, size_type __n1,
332 basic_string_view __str, size_type __pos2, size_type __n2) const
333 {
334 return this->substr(__pos1, __n1).compare(__str.substr(__pos2, __n2));
335 }
336
337 __attribute__((__nonnull__)) constexpr int
338 compare(const _CharT* __str) const noexcept
339 { return this->compare(basic_string_view{__str}); }
340
341 __attribute__((__nonnull__)) constexpr int
342 compare(size_type __pos1, size_type __n1, const _CharT* __str) const
343 { return this->substr(__pos1, __n1).compare(basic_string_view{__str}); }
344
345 constexpr int
346 compare(size_type __pos1, size_type __n1,
347 const _CharT* __str, size_type __n2) const noexcept(false)
348 {
349 return this->substr(__pos1, __n1)
350 .compare(basic_string_view(__str, __n2));
351 }
352
353#if __cplusplus > 201703L
354#define __cpp_lib_starts_ends_with 201711L
355 constexpr bool
356 starts_with(basic_string_view __x) const noexcept
357 { return this->substr(0, __x.size()) == __x; }
358
359 constexpr bool
360 starts_with(_CharT __x) const noexcept
361 { return !this->empty() && traits_type::eq(this->front(), __x); }
362
363 constexpr bool
364 starts_with(const _CharT* __x) const noexcept
365 { return this->starts_with(basic_string_view(__x)); }
366
367 constexpr bool
368 ends_with(basic_string_view __x) const noexcept
369 {
370 const auto __len = this->size();
371 const auto __xlen = __x.size();
372 return __len >= __xlen
373 && traits_type::compare(end() - __xlen, __x.data(), __xlen) == 0;
374 }
375
376 constexpr bool
377 ends_with(_CharT __x) const noexcept
378 { return !this->empty() && traits_type::eq(this->back(), __x); }
379
380 constexpr bool
381 ends_with(const _CharT* __x) const noexcept
382 { return this->ends_with(basic_string_view(__x)); }
383#endif // C++20
384
385#if __cplusplus > 202002L
386#define __cpp_lib_string_contains 202011L
387 constexpr bool
388 contains(basic_string_view __x) const noexcept
389 { return this->find(__x) != npos; }
390
391 constexpr bool
392 contains(_CharT __x) const noexcept
393 { return this->find(__x) != npos; }
394
395 constexpr bool
396 contains(const _CharT* __x) const noexcept
397 { return this->find(__x) != npos; }
398#endif // C++23
399
400 // [string.view.find], searching
401
402 constexpr size_type
403 find(basic_string_view __str, size_type __pos = 0) const noexcept
404 { return this->find(__str._M_str, __pos, __str._M_len); }
405
406 constexpr size_type
407 find(_CharT __c, size_type __pos = 0) const noexcept;
408
409 constexpr size_type
410 find(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
411
412 __attribute__((__nonnull__)) constexpr size_type
413 find(const _CharT* __str, size_type __pos = 0) const noexcept
414 { return this->find(__str, __pos, traits_type::length(__str)); }
415
416 constexpr size_type
417 rfind(basic_string_view __str, size_type __pos = npos) const noexcept
418 { return this->rfind(__str._M_str, __pos, __str._M_len); }
419
420 constexpr size_type
421 rfind(_CharT __c, size_type __pos = npos) const noexcept;
422
423 constexpr size_type
424 rfind(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
425
426 __attribute__((__nonnull__)) constexpr size_type
427 rfind(const _CharT* __str, size_type __pos = npos) const noexcept
428 { return this->rfind(__str, __pos, traits_type::length(__str)); }
429
430 constexpr size_type
431 find_first_of(basic_string_view __str, size_type __pos = 0) const noexcept
432 { return this->find_first_of(__str._M_str, __pos, __str._M_len); }
433
434 constexpr size_type
435 find_first_of(_CharT __c, size_type __pos = 0) const noexcept
436 { return this->find(__c, __pos); }
437
438 constexpr size_type
439 find_first_of(const _CharT* __str, size_type __pos,
440 size_type __n) const noexcept;
441
442 __attribute__((__nonnull__)) constexpr size_type
443 find_first_of(const _CharT* __str, size_type __pos = 0) const noexcept
444 { return this->find_first_of(__str, __pos, traits_type::length(__str)); }
445
446 constexpr size_type
447 find_last_of(basic_string_view __str,
448 size_type __pos = npos) const noexcept
449 { return this->find_last_of(__str._M_str, __pos, __str._M_len); }
450
451 constexpr size_type
452 find_last_of(_CharT __c, size_type __pos=npos) const noexcept
453 { return this->rfind(__c, __pos); }
454
455 constexpr size_type
456 find_last_of(const _CharT* __str, size_type __pos,
457 size_type __n) const noexcept;
458
459 __attribute__((__nonnull__)) constexpr size_type
460 find_last_of(const _CharT* __str, size_type __pos = npos) const noexcept
461 { return this->find_last_of(__str, __pos, traits_type::length(__str)); }
462
463 constexpr size_type
464 find_first_not_of(basic_string_view __str,
465 size_type __pos = 0) const noexcept
466 { return this->find_first_not_of(__str._M_str, __pos, __str._M_len); }
467
468 constexpr size_type
469 find_first_not_of(_CharT __c, size_type __pos = 0) const noexcept;
470
471 constexpr size_type
472 find_first_not_of(const _CharT* __str,
473 size_type __pos, size_type __n) const noexcept;
474
475 __attribute__((__nonnull__)) constexpr size_type
476 find_first_not_of(const _CharT* __str, size_type __pos = 0) const noexcept
477 {
478 return this->find_first_not_of(__str, __pos,
479 traits_type::length(__str));
480 }
481
482 constexpr size_type
483 find_last_not_of(basic_string_view __str,
484 size_type __pos = npos) const noexcept
485 { return this->find_last_not_of(__str._M_str, __pos, __str._M_len); }
486
487 constexpr size_type
488 find_last_not_of(_CharT __c, size_type __pos = npos) const noexcept;
489
490 constexpr size_type
491 find_last_not_of(const _CharT* __str,
492 size_type __pos, size_type __n) const noexcept;
493
494 __attribute__((__nonnull__)) constexpr size_type
495 find_last_not_of(const _CharT* __str,
496 size_type __pos = npos) const noexcept
497 {
498 return this->find_last_not_of(__str, __pos,
499 traits_type::length(__str));
500 }
501
502 private:
503
504 static constexpr int
505 _S_compare(size_type __n1, size_type __n2) noexcept
506 {
507 using __limits = __gnu_cxx::__int_traits<int>;
508 const difference_type __diff = __n1 - __n2;
509 if (__diff > __limits::__max)
510 return __limits::__max;
511 if (__diff < __limits::__min)
512 return __limits::__min;
513 return static_cast<int>(__diff);
514 }
515
516 size_t _M_len;
517 const _CharT* _M_str;
518 };
519
520#if __cplusplus > 201703L && __cpp_lib_concepts && __cpp_deduction_guides
521 template<contiguous_iterator _It, sized_sentinel_for<_It> _End>
522 basic_string_view(_It, _End) -> basic_string_view<iter_value_t<_It>>;
523
524#if __cplusplus > 202002L
525 template<ranges::contiguous_range _Range>
526 basic_string_view(_Range&&)
527 -> basic_string_view<ranges::range_value_t<_Range>>;
528#endif
529#endif
530
531 // [string.view.comparison], non-member basic_string_view comparison function
532
533 // Several of these functions use type_identity_t to create a non-deduced
534 // context, so that only one argument participates in template argument
535 // deduction and the other argument gets implicitly converted to the deduced
536 // type (see N3766).
537
538 template<typename _CharT, typename _Traits>
539 constexpr bool
540 operator==(basic_string_view<_CharT, _Traits> __x,
541 basic_string_view<_CharT, _Traits> __y) noexcept
542 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
543
544 template<typename _CharT, typename _Traits>
545 constexpr bool
546 operator==(basic_string_view<_CharT, _Traits> __x,
547 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
548 noexcept
549 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
550
551#if __cpp_lib_three_way_comparison
552 template<typename _CharT, typename _Traits>
553 constexpr auto
554 operator<=>(basic_string_view<_CharT, _Traits> __x,
555 basic_string_view<_CharT, _Traits> __y) noexcept
556 -> decltype(__detail::__char_traits_cmp_cat<_Traits>(0))
557 { return __detail::__char_traits_cmp_cat<_Traits>(__x.compare(__y)); }
558
559 template<typename _CharT, typename _Traits>
560 constexpr auto
561 operator<=>(basic_string_view<_CharT, _Traits> __x,
562 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
563 noexcept
564 -> decltype(__detail::__char_traits_cmp_cat<_Traits>(0))
565 { return __detail::__char_traits_cmp_cat<_Traits>(__x.compare(__y)); }
566#else
567 template<typename _CharT, typename _Traits>
568 constexpr bool
569 operator==(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
570 basic_string_view<_CharT, _Traits> __y) noexcept
571 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
572
573 template<typename _CharT, typename _Traits>
574 constexpr bool
575 operator!=(basic_string_view<_CharT, _Traits> __x,
576 basic_string_view<_CharT, _Traits> __y) noexcept
577 { return !(__x == __y); }
578
579 template<typename _CharT, typename _Traits>
580 constexpr bool
581 operator!=(basic_string_view<_CharT, _Traits> __x,
582 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
583 noexcept
584 { return !(__x == __y); }
585
586 template<typename _CharT, typename _Traits>
587 constexpr bool
588 operator!=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
589 basic_string_view<_CharT, _Traits> __y) noexcept
590 { return !(__x == __y); }
591
592 template<typename _CharT, typename _Traits>
593 constexpr bool
594 operator< (basic_string_view<_CharT, _Traits> __x,
595 basic_string_view<_CharT, _Traits> __y) noexcept
596 { return __x.compare(__y) < 0; }
597
598 template<typename _CharT, typename _Traits>
599 constexpr bool
600 operator< (basic_string_view<_CharT, _Traits> __x,
601 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
602 noexcept
603 { return __x.compare(__y) < 0; }
604
605 template<typename _CharT, typename _Traits>
606 constexpr bool
607 operator< (__type_identity_t<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 basic_string_view<_CharT, _Traits> __y) noexcept
615 { return __x.compare(__y) > 0; }
616
617 template<typename _CharT, typename _Traits>
618 constexpr bool
619 operator> (basic_string_view<_CharT, _Traits> __x,
620 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
621 noexcept
622 { return __x.compare(__y) > 0; }
623
624 template<typename _CharT, typename _Traits>
625 constexpr bool
626 operator> (__type_identity_t<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 basic_string_view<_CharT, _Traits> __y) noexcept
634 { return __x.compare(__y) <= 0; }
635
636 template<typename _CharT, typename _Traits>
637 constexpr bool
638 operator<=(basic_string_view<_CharT, _Traits> __x,
639 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
640 noexcept
641 { return __x.compare(__y) <= 0; }
642
643 template<typename _CharT, typename _Traits>
644 constexpr bool
645 operator<=(__type_identity_t<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 basic_string_view<_CharT, _Traits> __y) noexcept
653 { return __x.compare(__y) >= 0; }
654
655 template<typename _CharT, typename _Traits>
656 constexpr bool
657 operator>=(basic_string_view<_CharT, _Traits> __x,
658 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
659 noexcept
660 { return __x.compare(__y) >= 0; }
661
662 template<typename _CharT, typename _Traits>
663 constexpr bool
664 operator>=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
665 basic_string_view<_CharT, _Traits> __y) noexcept
666 { return __x.compare(__y) >= 0; }
667#endif // three-way comparison
668
669 // [string.view.io], Inserters and extractors
670 template<typename _CharT, typename _Traits>
671 inline basic_ostream<_CharT, _Traits>&
672 operator<<(basic_ostream<_CharT, _Traits>& __os,
673 basic_string_view<_CharT,_Traits> __str)
674 { return __ostream_insert(__os, __str.data(), __str.size()); }
675
676
677 // basic_string_view typedef names
678
679 using string_view = basic_string_view<char>;
680 using wstring_view = basic_string_view<wchar_t>;
681#ifdef _GLIBCXX_USE_CHAR8_T
682 using u8string_view = basic_string_view<char8_t>;
683#endif
684 using u16string_view = basic_string_view<char16_t>;
685 using u32string_view = basic_string_view<char32_t>;
686
687 // [string.view.hash], hash support:
688
689 template<typename _Tp>
690 struct hash;
691
692 template<>
693 struct hash<string_view>
694 : public __hash_base<size_t, string_view>
695 {
696 size_t
697 operator()(const string_view& __str) const noexcept
698 { return std::_Hash_impl::hash(ptr: __str.data(), clength: __str.length()); }
699 };
700
701 template<>
702 struct __is_fast_hash<hash<string_view>> : std::false_type
703 { };
704
705 template<>
706 struct hash<wstring_view>
707 : public __hash_base<size_t, wstring_view>
708 {
709 size_t
710 operator()(const wstring_view& __s) const noexcept
711 { return std::_Hash_impl::hash(ptr: __s.data(),
712 clength: __s.length() * sizeof(wchar_t)); }
713 };
714
715 template<>
716 struct __is_fast_hash<hash<wstring_view>> : std::false_type
717 { };
718
719#ifdef _GLIBCXX_USE_CHAR8_T
720 template<>
721 struct hash<u8string_view>
722 : public __hash_base<size_t, u8string_view>
723 {
724 size_t
725 operator()(const u8string_view& __str) const noexcept
726 { return std::_Hash_impl::hash(__str.data(), __str.length()); }
727 };
728
729 template<>
730 struct __is_fast_hash<hash<u8string_view>> : std::false_type
731 { };
732#endif
733
734 template<>
735 struct hash<u16string_view>
736 : public __hash_base<size_t, u16string_view>
737 {
738 size_t
739 operator()(const u16string_view& __s) const noexcept
740 { return std::_Hash_impl::hash(ptr: __s.data(),
741 clength: __s.length() * sizeof(char16_t)); }
742 };
743
744 template<>
745 struct __is_fast_hash<hash<u16string_view>> : std::false_type
746 { };
747
748 template<>
749 struct hash<u32string_view>
750 : public __hash_base<size_t, u32string_view>
751 {
752 size_t
753 operator()(const u32string_view& __s) const noexcept
754 { return std::_Hash_impl::hash(ptr: __s.data(),
755 clength: __s.length() * sizeof(char32_t)); }
756 };
757
758 template<>
759 struct __is_fast_hash<hash<u32string_view>> : std::false_type
760 { };
761
762 inline namespace literals
763 {
764 inline namespace string_view_literals
765 {
766#pragma GCC diagnostic push
767#pragma GCC diagnostic ignored "-Wliteral-suffix"
768 inline constexpr basic_string_view<char>
769 operator""sv(const char* __str, size_t __len) noexcept
770 { return basic_string_view<char>{__str, __len}; }
771
772 inline constexpr basic_string_view<wchar_t>
773 operator""sv(const wchar_t* __str, size_t __len) noexcept
774 { return basic_string_view<wchar_t>{__str, __len}; }
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
816