libstdc++
string_view
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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 noexcept(noexcept(__last - __first))
148 : _M_len(__last - __first), _M_str(std::to_address(__first))
149 { }
150
151#if __cplusplus > 202002L
152 template<typename _Range, typename _DRange = remove_cvref_t<_Range>>
153 requires (!is_same_v<_DRange, basic_string_view>)
154 && ranges::contiguous_range<_Range>
155 && ranges::sized_range<_Range>
156 && is_same_v<ranges::range_value_t<_Range>, _CharT>
157 && (!is_convertible_v<_Range, const _CharT*>)
158 && (!requires (_DRange& __d) {
159 __d.operator ::std::basic_string_view<_CharT, _Traits>();
160 })
161 && (!requires { typename _DRange::traits_type; }
162 || is_same_v<typename _DRange::traits_type, _Traits>)
163 constexpr explicit
164 basic_string_view(_Range&& __r)
165 noexcept(noexcept(ranges::size(__r)) && noexcept(ranges::data(__r)))
166 : _M_len(ranges::size(__r)), _M_str(ranges::data(__r))
167 { }
168#endif // C++23
169#endif // C++20
170
171 constexpr basic_string_view&
172 operator=(const basic_string_view&) noexcept = default;
173
174 // [string.view.iterators], iterator support
175
176 constexpr const_iterator
177 begin() const noexcept
178 { return this->_M_str; }
179
180 constexpr const_iterator
181 end() const noexcept
182 { return this->_M_str + this->_M_len; }
183
184 constexpr const_iterator
185 cbegin() const noexcept
186 { return this->_M_str; }
187
188 constexpr const_iterator
189 cend() const noexcept
190 { return this->_M_str + this->_M_len; }
191
192 constexpr const_reverse_iterator
193 rbegin() const noexcept
194 { return const_reverse_iterator(this->end()); }
195
196 constexpr const_reverse_iterator
197 rend() const noexcept
198 { return const_reverse_iterator(this->begin()); }
199
200 constexpr const_reverse_iterator
201 crbegin() const noexcept
202 { return const_reverse_iterator(this->end()); }
203
204 constexpr const_reverse_iterator
205 crend() const noexcept
206 { return const_reverse_iterator(this->begin()); }
207
208 // [string.view.capacity], capacity
209
210 constexpr size_type
211 size() const noexcept
212 { return this->_M_len; }
213
214 constexpr size_type
215 length() const noexcept
216 { return _M_len; }
217
218 constexpr size_type
219 max_size() const noexcept
220 {
221 return (npos - sizeof(size_type) - sizeof(void*))
222 / sizeof(value_type) / 4;
223 }
224
225 [[nodiscard]] constexpr bool
226 empty() const noexcept
227 { return this->_M_len == 0; }
228
229 // [string.view.access], element access
230
231 constexpr const_reference
232 operator[](size_type __pos) const noexcept
233 {
234 __glibcxx_assert(__pos < this->_M_len);
235 return *(this->_M_str + __pos);
236 }
237
238 constexpr const_reference
239 at(size_type __pos) const
240 {
241 if (__pos >= _M_len)
242 __throw_out_of_range_fmt(__N("basic_string_view::at: __pos "
243 "(which is %zu) >= this->size() "
244 "(which is %zu)"), __pos, this->size());
245 return *(this->_M_str + __pos);
246 }
247
248 constexpr const_reference
249 front() const noexcept
250 {
251 __glibcxx_assert(this->_M_len > 0);
252 return *this->_M_str;
253 }
254
255 constexpr const_reference
256 back() const noexcept
257 {
258 __glibcxx_assert(this->_M_len > 0);
259 return *(this->_M_str + this->_M_len - 1);
260 }
261
262 constexpr const_pointer
263 data() const noexcept
264 { return this->_M_str; }
265
266 // [string.view.modifiers], modifiers:
267
268 constexpr void
269 remove_prefix(size_type __n) noexcept
270 {
271 __glibcxx_assert(this->_M_len >= __n);
272 this->_M_str += __n;
273 this->_M_len -= __n;
274 }
275
276 constexpr void
277 remove_suffix(size_type __n) noexcept
278 {
279 __glibcxx_assert(this->_M_len >= __n);
280 this->_M_len -= __n;
281 }
282
283 constexpr void
284 swap(basic_string_view& __sv) noexcept
285 {
286 auto __tmp = *this;
287 *this = __sv;
288 __sv = __tmp;
289 }
290
291 // [string.view.ops], string operations:
292
293 _GLIBCXX20_CONSTEXPR
294 size_type
295 copy(_CharT* __str, size_type __n, size_type __pos = 0) const
296 {
297 __glibcxx_requires_string_len(__str, __n);
298 __pos = std::__sv_check(size(), __pos, "basic_string_view::copy");
299 const size_type __rlen = std::min(__n, _M_len - __pos);
300 // _GLIBCXX_RESOLVE_LIB_DEFECTS
301 // 2777. basic_string_view::copy should use char_traits::copy
302 traits_type::copy(__str, data() + __pos, __rlen);
303 return __rlen;
304 }
305
306 constexpr basic_string_view
307 substr(size_type __pos = 0, size_type __n = npos) const noexcept(false)
308 {
309 __pos = std::__sv_check(size(), __pos, "basic_string_view::substr");
310 const size_type __rlen = std::min(__n, _M_len - __pos);
311 return basic_string_view{_M_str + __pos, __rlen};
312 }
313
314 constexpr int
315 compare(basic_string_view __str) const noexcept
316 {
317 const size_type __rlen = std::min(this->_M_len, __str._M_len);
318 int __ret = traits_type::compare(this->_M_str, __str._M_str, __rlen);
319 if (__ret == 0)
320 __ret = _S_compare(this->_M_len, __str._M_len);
321 return __ret;
322 }
323
324 constexpr int
325 compare(size_type __pos1, size_type __n1, basic_string_view __str) const
326 { return this->substr(__pos1, __n1).compare(__str); }
327
328 constexpr int
329 compare(size_type __pos1, size_type __n1,
330 basic_string_view __str, size_type __pos2, size_type __n2) const
331 {
332 return this->substr(__pos1, __n1).compare(__str.substr(__pos2, __n2));
333 }
334
335 __attribute__((__nonnull__)) constexpr int
336 compare(const _CharT* __str) const noexcept
337 { return this->compare(basic_string_view{__str}); }
338
339 __attribute__((__nonnull__)) constexpr int
340 compare(size_type __pos1, size_type __n1, const _CharT* __str) const
341 { return this->substr(__pos1, __n1).compare(basic_string_view{__str}); }
342
343 constexpr int
344 compare(size_type __pos1, size_type __n1,
345 const _CharT* __str, size_type __n2) const noexcept(false)
346 {
347 return this->substr(__pos1, __n1)
348 .compare(basic_string_view(__str, __n2));
349 }
350
351#if __cplusplus > 201703L
352#define __cpp_lib_starts_ends_with 201711L
353 constexpr bool
354 starts_with(basic_string_view __x) const noexcept
355 { return this->substr(0, __x.size()) == __x; }
356
357 constexpr bool
358 starts_with(_CharT __x) const noexcept
359 { return !this->empty() && traits_type::eq(this->front(), __x); }
360
361 constexpr bool
362 starts_with(const _CharT* __x) const noexcept
363 { return this->starts_with(basic_string_view(__x)); }
364
365 constexpr bool
366 ends_with(basic_string_view __x) const noexcept
367 {
368 const auto __len = this->size();
369 const auto __xlen = __x.size();
370 return __len >= __xlen
371 && traits_type::compare(end() - __xlen, __x.data(), __xlen) == 0;
372 }
373
374 constexpr bool
375 ends_with(_CharT __x) const noexcept
376 { return !this->empty() && traits_type::eq(this->back(), __x); }
377
378 constexpr bool
379 ends_with(const _CharT* __x) const noexcept
380 { return this->ends_with(basic_string_view(__x)); }
381#endif // C++20
382
383#if __cplusplus > 202002L
384#define __cpp_lib_string_contains 202011L
385 constexpr bool
386 contains(basic_string_view __x) const noexcept
387 { return this->find(__x) != npos; }
388
389 constexpr bool
390 contains(_CharT __x) const noexcept
391 { return this->find(__x) != npos; }
392
393 constexpr bool
394 contains(const _CharT* __x) const noexcept
395 { return this->find(__x) != npos; }
396#endif // C++23
397
398 // [string.view.find], searching
399
400 constexpr size_type
401 find(basic_string_view __str, size_type __pos = 0) const noexcept
402 { return this->find(__str._M_str, __pos, __str._M_len); }
403
404 constexpr size_type
405 find(_CharT __c, size_type __pos = 0) const noexcept;
406
407 constexpr size_type
408 find(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
409
410 __attribute__((__nonnull__)) constexpr size_type
411 find(const _CharT* __str, size_type __pos = 0) const noexcept
412 { return this->find(__str, __pos, traits_type::length(__str)); }
413
414 constexpr size_type
415 rfind(basic_string_view __str, size_type __pos = npos) const noexcept
416 { return this->rfind(__str._M_str, __pos, __str._M_len); }
417
418 constexpr size_type
419 rfind(_CharT __c, size_type __pos = npos) const noexcept;
420
421 constexpr size_type
422 rfind(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
423
424 __attribute__((__nonnull__)) constexpr size_type
425 rfind(const _CharT* __str, size_type __pos = npos) const noexcept
426 { return this->rfind(__str, __pos, traits_type::length(__str)); }
427
428 constexpr size_type
429 find_first_of(basic_string_view __str, size_type __pos = 0) const noexcept
430 { return this->find_first_of(__str._M_str, __pos, __str._M_len); }
431
432 constexpr size_type
433 find_first_of(_CharT __c, size_type __pos = 0) const noexcept
434 { return this->find(__c, __pos); }
435
436 constexpr size_type
437 find_first_of(const _CharT* __str, size_type __pos,
438 size_type __n) const noexcept;
439
440 __attribute__((__nonnull__)) constexpr size_type
441 find_first_of(const _CharT* __str, size_type __pos = 0) const noexcept
442 { return this->find_first_of(__str, __pos, traits_type::length(__str)); }
443
444 constexpr size_type
445 find_last_of(basic_string_view __str,
446 size_type __pos = npos) const noexcept
447 { return this->find_last_of(__str._M_str, __pos, __str._M_len); }
448
449 constexpr size_type
450 find_last_of(_CharT __c, size_type __pos=npos) const noexcept
451 { return this->rfind(__c, __pos); }
452
453 constexpr size_type
454 find_last_of(const _CharT* __str, size_type __pos,
455 size_type __n) const noexcept;
456
457 __attribute__((__nonnull__)) constexpr size_type
458 find_last_of(const _CharT* __str, size_type __pos = npos) const noexcept
459 { return this->find_last_of(__str, __pos, traits_type::length(__str)); }
460
461 constexpr size_type
462 find_first_not_of(basic_string_view __str,
463 size_type __pos = 0) const noexcept
464 { return this->find_first_not_of(__str._M_str, __pos, __str._M_len); }
465
466 constexpr size_type
467 find_first_not_of(_CharT __c, size_type __pos = 0) const noexcept;
468
469 constexpr size_type
470 find_first_not_of(const _CharT* __str,
471 size_type __pos, size_type __n) const noexcept;
472
473 __attribute__((__nonnull__)) constexpr size_type
474 find_first_not_of(const _CharT* __str, size_type __pos = 0) const noexcept
475 {
476 return this->find_first_not_of(__str, __pos,
477 traits_type::length(__str));
478 }
479
480 constexpr size_type
481 find_last_not_of(basic_string_view __str,
482 size_type __pos = npos) const noexcept
483 { return this->find_last_not_of(__str._M_str, __pos, __str._M_len); }
484
485 constexpr size_type
486 find_last_not_of(_CharT __c, size_type __pos = npos) const noexcept;
487
488 constexpr size_type
489 find_last_not_of(const _CharT* __str,
490 size_type __pos, size_type __n) const noexcept;
491
492 __attribute__((__nonnull__)) constexpr size_type
493 find_last_not_of(const _CharT* __str,
494 size_type __pos = npos) const noexcept
495 {
496 return this->find_last_not_of(__str, __pos,
497 traits_type::length(__str));
498 }
499
500 private:
501
502 static constexpr int
503 _S_compare(size_type __n1, size_type __n2) noexcept
504 {
505 using __limits = __gnu_cxx::__int_traits<int>;
506 const difference_type __diff = __n1 - __n2;
507 if (__diff > __limits::__max)
508 return __limits::__max;
509 if (__diff < __limits::__min)
510 return __limits::__min;
511 return static_cast<int>(__diff);
512 }
513
514 size_t _M_len;
515 const _CharT* _M_str;
516 };
517
518#if __cplusplus > 201703L && __cpp_lib_concepts && __cpp_deduction_guides
519 template<contiguous_iterator _It, sized_sentinel_for<_It> _End>
520 basic_string_view(_It, _End) -> basic_string_view<iter_value_t<_It>>;
521
522#if __cplusplus > 202002L
523 template<ranges::contiguous_range _Range>
524 basic_string_view(_Range&&)
525 -> basic_string_view<ranges::range_value_t<_Range>>;
526#endif
527#endif
528
529 // [string.view.comparison], non-member basic_string_view comparison function
530
531 // Several of these functions use type_identity_t to create a non-deduced
532 // context, so that only one argument participates in template argument
533 // deduction and the other argument gets implicitly converted to the deduced
534 // type (see N3766).
535
536 template<typename _CharT, typename _Traits>
537 constexpr bool
538 operator==(basic_string_view<_CharT, _Traits> __x,
539 basic_string_view<_CharT, _Traits> __y) noexcept
540 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
541
542 template<typename _CharT, typename _Traits>
543 constexpr bool
544 operator==(basic_string_view<_CharT, _Traits> __x,
545 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
546 noexcept
547 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
548
549#if __cpp_lib_three_way_comparison
550 template<typename _CharT, typename _Traits>
551 constexpr auto
552 operator<=>(basic_string_view<_CharT, _Traits> __x,
553 basic_string_view<_CharT, _Traits> __y) noexcept
554 -> decltype(__detail::__char_traits_cmp_cat<_Traits>(0))
555 { return __detail::__char_traits_cmp_cat<_Traits>(__x.compare(__y)); }
556
557 template<typename _CharT, typename _Traits>
558 constexpr auto
559 operator<=>(basic_string_view<_CharT, _Traits> __x,
560 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
561 noexcept
562 -> decltype(__detail::__char_traits_cmp_cat<_Traits>(0))
563 { return __detail::__char_traits_cmp_cat<_Traits>(__x.compare(__y)); }
564#else
565 template<typename _CharT, typename _Traits>
566 constexpr bool
567 operator==(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
568 basic_string_view<_CharT, _Traits> __y) noexcept
569 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
570
571 template<typename _CharT, typename _Traits>
572 constexpr bool
573 operator!=(basic_string_view<_CharT, _Traits> __x,
574 basic_string_view<_CharT, _Traits> __y) noexcept
575 { return !(__x == __y); }
576
577 template<typename _CharT, typename _Traits>
578 constexpr bool
579 operator!=(basic_string_view<_CharT, _Traits> __x,
580 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
581 noexcept
582 { return !(__x == __y); }
583
584 template<typename _CharT, typename _Traits>
585 constexpr bool
586 operator!=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
587 basic_string_view<_CharT, _Traits> __y) noexcept
588 { return !(__x == __y); }
589
590 template<typename _CharT, typename _Traits>
591 constexpr bool
592 operator< (basic_string_view<_CharT, _Traits> __x,
593 basic_string_view<_CharT, _Traits> __y) noexcept
594 { return __x.compare(__y) < 0; }
595
596 template<typename _CharT, typename _Traits>
597 constexpr bool
598 operator< (basic_string_view<_CharT, _Traits> __x,
599 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
600 noexcept
601 { return __x.compare(__y) < 0; }
602
603 template<typename _CharT, typename _Traits>
604 constexpr bool
605 operator< (__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
606 basic_string_view<_CharT, _Traits> __y) noexcept
607 { return __x.compare(__y) < 0; }
608
609 template<typename _CharT, typename _Traits>
610 constexpr bool
611 operator> (basic_string_view<_CharT, _Traits> __x,
612 basic_string_view<_CharT, _Traits> __y) noexcept
613 { return __x.compare(__y) > 0; }
614
615 template<typename _CharT, typename _Traits>
616 constexpr bool
617 operator> (basic_string_view<_CharT, _Traits> __x,
618 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
619 noexcept
620 { return __x.compare(__y) > 0; }
621
622 template<typename _CharT, typename _Traits>
623 constexpr bool
624 operator> (__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
625 basic_string_view<_CharT, _Traits> __y) noexcept
626 { return __x.compare(__y) > 0; }
627
628 template<typename _CharT, typename _Traits>
629 constexpr bool
630 operator<=(basic_string_view<_CharT, _Traits> __x,
631 basic_string_view<_CharT, _Traits> __y) noexcept
632 { return __x.compare(__y) <= 0; }
633
634 template<typename _CharT, typename _Traits>
635 constexpr bool
636 operator<=(basic_string_view<_CharT, _Traits> __x,
637 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
638 noexcept
639 { return __x.compare(__y) <= 0; }
640
641 template<typename _CharT, typename _Traits>
642 constexpr bool
643 operator<=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
644 basic_string_view<_CharT, _Traits> __y) noexcept
645 { return __x.compare(__y) <= 0; }
646
647 template<typename _CharT, typename _Traits>
648 constexpr bool
649 operator>=(basic_string_view<_CharT, _Traits> __x,
650 basic_string_view<_CharT, _Traits> __y) noexcept
651 { return __x.compare(__y) >= 0; }
652
653 template<typename _CharT, typename _Traits>
654 constexpr bool
655 operator>=(basic_string_view<_CharT, _Traits> __x,
656 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
657 noexcept
658 { return __x.compare(__y) >= 0; }
659
660 template<typename _CharT, typename _Traits>
661 constexpr bool
662 operator>=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
663 basic_string_view<_CharT, _Traits> __y) noexcept
664 { return __x.compare(__y) >= 0; }
665#endif // three-way comparison
666
667 // [string.view.io], Inserters and extractors
668 template<typename _CharT, typename _Traits>
669 inline basic_ostream<_CharT, _Traits>&
670 operator<<(basic_ostream<_CharT, _Traits>& __os,
671 basic_string_view<_CharT,_Traits> __str)
672 { return __ostream_insert(__os, __str.data(), __str.size()); }
673
674
675 // basic_string_view typedef names
676
677 using string_view = basic_string_view<char>;
678#ifdef _GLIBCXX_USE_WCHAR_T
679 using wstring_view = basic_string_view<wchar_t>;
680#endif
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(__str.data(), __str.length()); }
699 };
700
701 template<>
702 struct __is_fast_hash<hash<string_view>> : std::false_type
703 { };
704
705#ifdef _GLIBCXX_USE_WCHAR_T
706 template<>
707 struct hash<wstring_view>
708 : public __hash_base<size_t, wstring_view>
709 {
710 size_t
711 operator()(const wstring_view& __s) const noexcept
712 { return std::_Hash_impl::hash(__s.data(),
713 __s.length() * sizeof(wchar_t)); }
714 };
715
716 template<>
717 struct __is_fast_hash<hash<wstring_view>> : std::false_type
718 { };
719#endif
720
721#ifdef _GLIBCXX_USE_CHAR8_T
722 template<>
723 struct hash<u8string_view>
724 : public __hash_base<size_t, u8string_view>
725 {
726 size_t
727 operator()(const u8string_view& __str) const noexcept
728 { return std::_Hash_impl::hash(__str.data(), __str.length()); }
729 };
730
731 template<>
732 struct __is_fast_hash<hash<u8string_view>> : std::false_type
733 { };
734#endif
735
736 template<>
737 struct hash<u16string_view>
738 : public __hash_base<size_t, u16string_view>
739 {
740 size_t
741 operator()(const u16string_view& __s) const noexcept
742 { return std::_Hash_impl::hash(__s.data(),
743 __s.length() * sizeof(char16_t)); }
744 };
745
746 template<>
747 struct __is_fast_hash<hash<u16string_view>> : std::false_type
748 { };
749
750 template<>
751 struct hash<u32string_view>
752 : public __hash_base<size_t, u32string_view>
753 {
754 size_t
755 operator()(const u32string_view& __s) const noexcept
756 { return std::_Hash_impl::hash(__s.data(),
757 __s.length() * sizeof(char32_t)); }
758 };
759
760 template<>
761 struct __is_fast_hash<hash<u32string_view>> : std::false_type
762 { };
763
764 inline namespace literals
765 {
766 inline namespace string_view_literals
767 {
768#pragma GCC diagnostic push
769#pragma GCC diagnostic ignored "-Wliteral-suffix"
770 inline constexpr basic_string_view<char>
771 operator""sv(const char* __str, size_t __len) noexcept
772 { return basic_string_view<char>{__str, __len}; }
773
774#ifdef _GLIBCXX_USE_WCHAR_T
775 inline constexpr basic_string_view<wchar_t>
776 operator""sv(const wchar_t* __str, size_t __len) noexcept
777 { return basic_string_view<wchar_t>{__str, __len}; }
778#endif
779
780#ifdef _GLIBCXX_USE_CHAR8_T
781 inline constexpr basic_string_view<char8_t>
782 operator""sv(const char8_t* __str, size_t __len) noexcept
783 { return basic_string_view<char8_t>{__str, __len}; }
784#endif
785
786 inline constexpr basic_string_view<char16_t>
787 operator""sv(const char16_t* __str, size_t __len) noexcept
788 { return basic_string_view<char16_t>{__str, __len}; }
789
790 inline constexpr basic_string_view<char32_t>
791 operator""sv(const char32_t* __str, size_t __len) noexcept
792 { return basic_string_view<char32_t>{__str, __len}; }
793
794#pragma GCC diagnostic pop
795 } // namespace string_literals
796 } // namespace literals
797
798#if __cpp_lib_concepts
799 namespace ranges
800 {
801 // Opt-in to borrowed_range concept
802 template<typename _CharT, typename _Traits>
803 inline constexpr bool
804 enable_borrowed_range<basic_string_view<_CharT, _Traits>> = true;
805
806 // Opt-in to view concept
807 template<typename _CharT, typename _Traits>
808 inline constexpr bool
809 enable_view<basic_string_view<_CharT, _Traits>> = true;
810 }
811#endif
812_GLIBCXX_END_NAMESPACE_VERSION
813} // namespace std
814
815#include <bits/string_view.tcc>
816
817#endif // __cplusplus <= 201402L
818
819#endif // _GLIBCXX_EXPERIMENTAL_STRING_VIEW
std::false_type
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition type_traits:86
std::min
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition stl_algobase.h:230
std
ISO C++ entities toplevel namespace is std.
std::operator<<
std::basic_ostream< _CharT, _Traits > & operator<<(std::basic_ostream< _CharT, _Traits > &__os, const bitset< _Nb > &__x)
Global I/O operators for bitsets.
Definition bitset:1540
std::literals
ISO C++ inline namespace for literal suffixes.
__gnu_cxx::__int_traits
__numeric_traits_integer< _Tp > __int_traits
Convenience alias for __numeric_traits<integer-type>.
Definition ext/numeric_traits.h:136
std::basic_ostream
Template class basic_ostream.
Definition ostream:59
std::basic_string_view
A non-owning reference to a string.
Definition string_view:99
std::hash
Primary class template hash.
Definition functional_hash.h:103