libstdc++
string_view
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1// Components for manipulating non-owning sequences of characters -*- C++ -*-
2
3// Copyright (C) 2013-2025 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#ifdef _GLIBCXX_SYSHDR
37#pragma GCC system_header
38#endif
39
40#define __glibcxx_want_constexpr_char_traits
41#define __glibcxx_want_constexpr_string_view
42#define __glibcxx_want_freestanding_string_view
43#define __glibcxx_want_string_view
44#define __glibcxx_want_starts_ends_with
45#define __glibcxx_want_string_contains
46#include <bits/version.h>
47
48#if __cplusplus >= 201703L
49
50#include <bits/char_traits.h>
51#include <bits/functexcept.h>
52#include <bits/functional_hash.h>
53#include <bits/range_access.h>
54#include <bits/stl_algobase.h>
55#include <ext/numeric_traits.h>
56
57#if __cplusplus >= 202002L
58# include <bits/ranges_base.h>
59#endif
60
61#if _GLIBCXX_HOSTED
62# include <iosfwd>
63# include <bits/ostream_insert.h>
64#endif
65
66namespace std _GLIBCXX_VISIBILITY(default)
67{
68_GLIBCXX_BEGIN_NAMESPACE_VERSION
69
70 // Helper for basic_string and basic_string_view members.
71 constexpr size_t
72 __sv_check(size_t __size, size_t __pos, const char* __s)
73 {
74 if (__pos > __size)
75 __throw_out_of_range_fmt(__N("%s: __pos (which is %zu) > __size "
76 "(which is %zu)"), __s, __pos, __size);
77 return __pos;
78 }
79
80 // Helper for basic_string members.
81 // NB: __sv_limit doesn't check for a bad __pos value.
82 constexpr size_t
83 __sv_limit(size_t __size, size_t __pos, size_t __off) noexcept
84 {
85 const bool __testoff = __off < __size - __pos;
86 return __testoff ? __off : __size - __pos;
87 }
88
89 /**
90 * @class basic_string_view <string_view>
91 * @brief A non-owning reference to a string.
92 *
93 * @ingroup strings
94 * @ingroup sequences
95 *
96 * @tparam _CharT Type of character
97 * @tparam _Traits Traits for character type, defaults to
98 * char_traits<_CharT>.
99 *
100 * A basic_string_view looks like this:
101 *
102 * @code
103 * _CharT* _M_str
104 * size_t _M_len
105 * @endcode
106 */
107 template<typename _CharT, typename _Traits = std::char_traits<_CharT>>
108 class basic_string_view
109 {
110 static_assert(!is_array_v<_CharT>);
111 static_assert(is_trivially_copyable_v<_CharT>
112 && is_trivially_default_constructible_v<_CharT>
113 && is_standard_layout_v<_CharT>);
114 static_assert(is_same_v<_CharT, typename _Traits::char_type>);
115
116 public:
117
118 // types
119 using traits_type = _Traits;
120 using value_type = _CharT;
121 using pointer = value_type*;
122 using const_pointer = const value_type*;
123 using reference = value_type&;
124 using const_reference = const value_type&;
125 using const_iterator = const value_type*;
126 using iterator = const_iterator;
127 using const_reverse_iterator = std::reverse_iterator<const_iterator>;
128 using reverse_iterator = const_reverse_iterator;
129 using size_type = size_t;
130 using difference_type = ptrdiff_t;
131 static constexpr size_type npos = size_type(-1);
132
133 // [string.view.cons], construction and assignment
134
135 constexpr
136 basic_string_view() noexcept
137 : _M_len{0}, _M_str{nullptr}
138 { }
139
140 constexpr basic_string_view(const basic_string_view&) noexcept = default;
141
142 [[__gnu__::__nonnull__]]
143 constexpr
144 basic_string_view(const _CharT* __str) noexcept
145 : _M_len{traits_type::length(__str)},
146 _M_str{__str}
147 { }
148
149 constexpr
150 basic_string_view(const _CharT* __str, size_type __len) noexcept
151 : _M_len{__len}, _M_str{__str}
152 { }
153
154#if __cplusplus >= 202002L && __cpp_lib_concepts
155 template<contiguous_iterator _It, sized_sentinel_for<_It> _End>
156 requires same_as<iter_value_t<_It>, _CharT>
157 && (!convertible_to<_End, size_type>)
158 constexpr
159 basic_string_view(_It __first, _End __last)
160 noexcept(noexcept(__last - __first))
161 : _M_len(__last - __first), _M_str(std::to_address(__first))
162 { }
163
164#if __cplusplus > 202002L
165 template<typename _Range, typename _DRange = remove_cvref_t<_Range>>
166 requires (!is_same_v<_DRange, basic_string_view>)
167 && ranges::contiguous_range<_Range>
168 && ranges::sized_range<_Range>
169 && is_same_v<ranges::range_value_t<_Range>, _CharT>
170 && (!is_convertible_v<_Range, const _CharT*>)
171 && (!requires (_DRange& __d) {
172 __d.operator ::std::basic_string_view<_CharT, _Traits>();
173 })
174 constexpr explicit
175 basic_string_view(_Range&& __r)
176 noexcept(noexcept(ranges::size(__r)) && noexcept(ranges::data(__r)))
177 : _M_len(ranges::size(__r)), _M_str(ranges::data(__r))
178 { }
179
180 basic_string_view(nullptr_t) = delete;
181#endif // C++23
182#endif // C++20
183
184 constexpr basic_string_view&
185 operator=(const basic_string_view&) noexcept = default;
186
187 // [string.view.iterators], iterator support
188
189 [[nodiscard]]
190 constexpr const_iterator
191 begin() const noexcept
192 { return this->_M_str; }
193
194 [[nodiscard]]
195 constexpr const_iterator
196 end() const noexcept
197 { return this->_M_str + this->_M_len; }
198
199 [[nodiscard]]
200 constexpr const_iterator
201 cbegin() const noexcept
202 { return this->_M_str; }
203
204 [[nodiscard]]
205 constexpr const_iterator
206 cend() const noexcept
207 { return this->_M_str + this->_M_len; }
208
209 [[nodiscard]]
210 constexpr const_reverse_iterator
211 rbegin() const noexcept
212 { return const_reverse_iterator(this->end()); }
213
214 [[nodiscard]]
215 constexpr const_reverse_iterator
216 rend() const noexcept
217 { return const_reverse_iterator(this->begin()); }
218
219 [[nodiscard]]
220 constexpr const_reverse_iterator
221 crbegin() const noexcept
222 { return const_reverse_iterator(this->end()); }
223
224 [[nodiscard]]
225 constexpr const_reverse_iterator
226 crend() const noexcept
227 { return const_reverse_iterator(this->begin()); }
228
229 // [string.view.capacity], capacity
230
231 [[nodiscard]]
232 constexpr size_type
233 size() const noexcept
234 { return this->_M_len; }
235
236 [[nodiscard]]
237 constexpr size_type
238 length() const noexcept
239 { return _M_len; }
240
241 [[nodiscard]]
242 constexpr size_type
243 max_size() const noexcept
244 {
245 return (npos - sizeof(size_type) - sizeof(void*))
246 / sizeof(value_type) / 4;
247 }
248
249 [[nodiscard]]
250 constexpr bool
251 empty() const noexcept
252 { return this->_M_len == 0; }
253
254 // [string.view.access], element access
255
256 [[nodiscard]]
257 constexpr const_reference
258 operator[](size_type __pos) const noexcept
259 {
260 __glibcxx_assert(__pos < this->_M_len);
261 return *(this->_M_str + __pos);
262 }
263
264 [[nodiscard]]
265 constexpr const_reference
266 at(size_type __pos) const
267 {
268 if (__pos >= _M_len)
269 __throw_out_of_range_fmt(__N("basic_string_view::at: __pos "
270 "(which is %zu) >= this->size() "
271 "(which is %zu)"), __pos, this->size());
272 return *(this->_M_str + __pos);
273 }
274
275 [[nodiscard]]
276 constexpr const_reference
277 front() const noexcept
278 {
279 __glibcxx_assert(this->_M_len > 0);
280 return *this->_M_str;
281 }
282
283 [[nodiscard]]
284 constexpr const_reference
285 back() const noexcept
286 {
287 __glibcxx_assert(this->_M_len > 0);
288 return *(this->_M_str + this->_M_len - 1);
289 }
290
291 [[nodiscard]]
292 constexpr const_pointer
293 data() const noexcept
294 { return this->_M_str; }
295
296 // [string.view.modifiers], modifiers:
297
298 constexpr void
299 remove_prefix(size_type __n) noexcept
300 {
301 __glibcxx_assert(this->_M_len >= __n);
302 this->_M_str += __n;
303 this->_M_len -= __n;
304 }
305
306 constexpr void
307 remove_suffix(size_type __n) noexcept
308 {
309 __glibcxx_assert(this->_M_len >= __n);
310 this->_M_len -= __n;
311 }
312
313 constexpr void
314 swap(basic_string_view& __sv) noexcept
315 {
316 auto __tmp = *this;
317 *this = __sv;
318 __sv = __tmp;
319 }
320
321 // [string.view.ops], string operations:
322
323 _GLIBCXX20_CONSTEXPR
324 size_type
325 copy(_CharT* __str, size_type __n, size_type __pos = 0) const
326 {
327 __glibcxx_requires_string_len(__str, __n);
328 __pos = std::__sv_check(size(), __pos, "basic_string_view::copy");
329 const size_type __rlen = std::min<size_t>(__n, _M_len - __pos);
330 // _GLIBCXX_RESOLVE_LIB_DEFECTS
331 // 2777. basic_string_view::copy should use char_traits::copy
332 traits_type::copy(__str, data() + __pos, __rlen);
333 return __rlen;
334 }
335
336 [[nodiscard]]
337 constexpr basic_string_view
338 substr(size_type __pos = 0, size_type __n = npos) const noexcept(false)
339 {
340 __pos = std::__sv_check(size(), __pos, "basic_string_view::substr");
341 const size_type __rlen = std::min<size_t>(__n, _M_len - __pos);
342 return basic_string_view{_M_str + __pos, __rlen};
343 }
344
345 [[nodiscard]]
346 constexpr int
347 compare(basic_string_view __str) const noexcept
348 {
349 const size_type __rlen = std::min(this->_M_len, __str._M_len);
350 int __ret = traits_type::compare(this->_M_str, __str._M_str, __rlen);
351 if (__ret == 0)
352 __ret = _S_compare(this->_M_len, __str._M_len);
353 return __ret;
354 }
355
356 [[nodiscard]]
357 constexpr int
358 compare(size_type __pos1, size_type __n1, basic_string_view __str) const
359 { return this->substr(__pos1, __n1).compare(__str); }
360
361 [[nodiscard]]
362 constexpr int
363 compare(size_type __pos1, size_type __n1,
364 basic_string_view __str, size_type __pos2, size_type __n2) const
365 {
366 return this->substr(__pos1, __n1).compare(__str.substr(__pos2, __n2));
367 }
368
369 [[nodiscard, __gnu__::__nonnull__]]
370 constexpr int
371 compare(const _CharT* __str) const noexcept
372 { return this->compare(basic_string_view{__str}); }
373
374 [[nodiscard, __gnu__::__nonnull__]]
375 constexpr int
376 compare(size_type __pos1, size_type __n1, const _CharT* __str) const
377 { return this->substr(__pos1, __n1).compare(basic_string_view{__str}); }
378
379 [[nodiscard]]
380 constexpr int
381 compare(size_type __pos1, size_type __n1,
382 const _CharT* __str, size_type __n2) const noexcept(false)
383 {
384 return this->substr(__pos1, __n1)
385 .compare(basic_string_view(__str, __n2));
386 }
387
388#ifdef __cpp_lib_starts_ends_with // C++ >= 20
389 [[nodiscard]]
390 constexpr bool
391 starts_with(basic_string_view __x) const noexcept
392 {
393 return _M_len >= __x._M_len
394 && traits_type::compare(_M_str, __x._M_str, __x._M_len) == 0;
395 }
396
397 [[nodiscard]]
398 constexpr bool
399 starts_with(_CharT __x) const noexcept
400 { return !this->empty() && traits_type::eq(this->front(), __x); }
401
402 [[nodiscard, __gnu__::__nonnull__]]
403 constexpr bool
404 starts_with(const _CharT* __x) const noexcept
405 { return this->starts_with(basic_string_view(__x)); }
406
407 [[nodiscard]]
408 constexpr bool
409 ends_with(basic_string_view __x) const noexcept
410 {
411 const auto __len = this->size();
412 const auto __xlen = __x.size();
413 return __len >= __xlen
414 && traits_type::compare(end() - __xlen, __x.data(), __xlen) == 0;
415 }
416
417 [[nodiscard]]
418 constexpr bool
419 ends_with(_CharT __x) const noexcept
420 { return !this->empty() && traits_type::eq(this->back(), __x); }
421
422 [[nodiscard, __gnu__::__nonnull__]]
423 constexpr bool
424 ends_with(const _CharT* __x) const noexcept
425 { return this->ends_with(basic_string_view(__x)); }
426#endif // __cpp_lib_starts_ends_with
427
428#if __cplusplus > 202002L
429#if _GLIBCXX_HOSTED && !defined(__cpp_lib_string_contains)
430 // This FTM is not freestanding as it also implies matching <string>
431 // support, and <string> is omitted from the freestanding subset.
432# error "libstdc++ bug: string_contains not defined when it should be"
433#endif // HOSTED
434 [[nodiscard]]
435 constexpr bool
436 contains(basic_string_view __x) const noexcept
437 { return this->find(__x) != npos; }
438
439 [[nodiscard]]
440 constexpr bool
441 contains(_CharT __x) const noexcept
442 { return this->find(__x) != npos; }
443
444 [[nodiscard, __gnu__::__nonnull__]]
445 constexpr bool
446 contains(const _CharT* __x) const noexcept
447 { return this->find(__x) != npos; }
448#endif // C++23
449
450 // [string.view.find], searching
451
452 [[nodiscard]]
453 constexpr size_type
454 find(basic_string_view __str, size_type __pos = 0) const noexcept
455 { return this->find(__str._M_str, __pos, __str._M_len); }
456
457 [[nodiscard]]
458 constexpr size_type
459 find(_CharT __c, size_type __pos = 0) const noexcept;
460
461 [[nodiscard]]
462 constexpr size_type
463 find(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
464
465 [[nodiscard, __gnu__::__nonnull__]]
466 constexpr size_type
467 find(const _CharT* __str, size_type __pos = 0) const noexcept
468 { return this->find(__str, __pos, traits_type::length(__str)); }
469
470 [[nodiscard]]
471 constexpr size_type
472 rfind(basic_string_view __str, size_type __pos = npos) const noexcept
473 { return this->rfind(__str._M_str, __pos, __str._M_len); }
474
475 [[nodiscard]]
476 constexpr size_type
477 rfind(_CharT __c, size_type __pos = npos) const noexcept;
478
479 [[nodiscard]]
480 constexpr size_type
481 rfind(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
482
483 [[nodiscard, __gnu__::__nonnull__]]
484 constexpr size_type
485 rfind(const _CharT* __str, size_type __pos = npos) const noexcept
486 { return this->rfind(__str, __pos, traits_type::length(__str)); }
487
488 [[nodiscard]]
489 constexpr size_type
490 find_first_of(basic_string_view __str, size_type __pos = 0) const noexcept
491 { return this->find_first_of(__str._M_str, __pos, __str._M_len); }
492
493 [[nodiscard]]
494 constexpr size_type
495 find_first_of(_CharT __c, size_type __pos = 0) const noexcept
496 { return this->find(__c, __pos); }
497
498 [[nodiscard]]
499 constexpr size_type
500 find_first_of(const _CharT* __str, size_type __pos,
501 size_type __n) const noexcept;
502
503 [[nodiscard, __gnu__::__nonnull__]]
504 constexpr size_type
505 find_first_of(const _CharT* __str, size_type __pos = 0) const noexcept
506 { return this->find_first_of(__str, __pos, traits_type::length(__str)); }
507
508 [[nodiscard]]
509 constexpr size_type
510 find_last_of(basic_string_view __str,
511 size_type __pos = npos) const noexcept
512 { return this->find_last_of(__str._M_str, __pos, __str._M_len); }
513
514 [[nodiscard]]
515 constexpr size_type
516 find_last_of(_CharT __c, size_type __pos=npos) const noexcept
517 { return this->rfind(__c, __pos); }
518
519 [[nodiscard]]
520 constexpr size_type
521 find_last_of(const _CharT* __str, size_type __pos,
522 size_type __n) const noexcept;
523
524 [[nodiscard, __gnu__::__nonnull__]]
525 constexpr size_type
526 find_last_of(const _CharT* __str, size_type __pos = npos) const noexcept
527 { return this->find_last_of(__str, __pos, traits_type::length(__str)); }
528
529 [[nodiscard]]
530 constexpr size_type
531 find_first_not_of(basic_string_view __str,
532 size_type __pos = 0) const noexcept
533 { return this->find_first_not_of(__str._M_str, __pos, __str._M_len); }
534
535 [[nodiscard]]
536 constexpr size_type
537 find_first_not_of(_CharT __c, size_type __pos = 0) const noexcept;
538
539 [[nodiscard]]
540 constexpr size_type
541 find_first_not_of(const _CharT* __str,
542 size_type __pos, size_type __n) const noexcept;
543
544 [[nodiscard, __gnu__::__nonnull__]]
545 constexpr size_type
546 find_first_not_of(const _CharT* __str, size_type __pos = 0) const noexcept
547 {
548 return this->find_first_not_of(__str, __pos,
549 traits_type::length(__str));
550 }
551
552 [[nodiscard]]
553 constexpr size_type
554 find_last_not_of(basic_string_view __str,
555 size_type __pos = npos) const noexcept
556 { return this->find_last_not_of(__str._M_str, __pos, __str._M_len); }
557
558 [[nodiscard]]
559 constexpr size_type
560 find_last_not_of(_CharT __c, size_type __pos = npos) const noexcept;
561
562 [[nodiscard]]
563 constexpr size_type
564 find_last_not_of(const _CharT* __str,
565 size_type __pos, size_type __n) const noexcept;
566
567 [[nodiscard, __gnu__::__nonnull__]]
568 constexpr size_type
569 find_last_not_of(const _CharT* __str,
570 size_type __pos = npos) const noexcept
571 {
572 return this->find_last_not_of(__str, __pos,
573 traits_type::length(__str));
574 }
575
576 private:
577
578 static constexpr int
579 _S_compare(size_type __n1, size_type __n2) noexcept
580 {
581 using __limits = __gnu_cxx::__int_traits<int>;
582 const difference_type __diff = __n1 - __n2;
583 if (__diff > __limits::__max)
584 return __limits::__max;
585 if (__diff < __limits::__min)
586 return __limits::__min;
587 return static_cast<int>(__diff);
588 }
589
590 size_t _M_len;
591 const _CharT* _M_str;
592 };
593
594#if __cplusplus > 201703L && __cpp_lib_concepts && __cpp_deduction_guides
595 template<contiguous_iterator _It, sized_sentinel_for<_It> _End>
596 basic_string_view(_It, _End) -> basic_string_view<iter_value_t<_It>>;
597
598#if __cplusplus > 202002L
599 template<ranges::contiguous_range _Range>
600 basic_string_view(_Range&&)
601 -> basic_string_view<ranges::range_value_t<_Range>>;
602#endif
603#endif
604
605 // [string.view.comparison], non-member basic_string_view comparison function
606
607 // Several of these functions use type_identity_t to create a non-deduced
608 // context, so that only one argument participates in template argument
609 // deduction and the other argument gets implicitly converted to the deduced
610 // type (see N3766).
611
612#if __cpp_lib_three_way_comparison
613 // _GLIBCXX_RESOLVE_LIB_DEFECTS
614 // 3950. std::basic_string_view comparison operators are overspecified
615
616 template<typename _CharT, typename _Traits>
617 [[nodiscard]]
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.size() == __y.size() && __x.compare(__y) == 0; }
623
624 template<typename _CharT, typename _Traits>
625 [[nodiscard]]
626 constexpr auto
627 operator<=>(basic_string_view<_CharT, _Traits> __x,
628 type_identity_t<basic_string_view<_CharT, _Traits>> __y)
629 noexcept
630 -> decltype(__detail::__char_traits_cmp_cat<_Traits>(0))
631 { return __detail::__char_traits_cmp_cat<_Traits>(__x.compare(__y)); }
632#else
633 template<typename _CharT, typename _Traits>
634 [[nodiscard]]
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.size() == __y.size() && __x.compare(__y) == 0; }
640
641 template<typename _CharT, typename _Traits>
642 [[nodiscard]]
643 constexpr bool
644 operator==(basic_string_view<_CharT, _Traits> __x,
645 basic_string_view<_CharT, _Traits> __y) noexcept
646 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
647
648 template<typename _CharT, typename _Traits>
649 [[nodiscard]]
650 constexpr bool
651 operator==(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
652 basic_string_view<_CharT, _Traits> __y) noexcept
653 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
654
655 template<typename _CharT, typename _Traits>
656 [[nodiscard]]
657 constexpr bool
658 operator!=(basic_string_view<_CharT, _Traits> __x,
659 basic_string_view<_CharT, _Traits> __y) noexcept
660 { return !(__x == __y); }
661
662 template<typename _CharT, typename _Traits>
663 [[nodiscard]]
664 constexpr bool
665 operator!=(basic_string_view<_CharT, _Traits> __x,
666 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
667 noexcept
668 { return !(__x == __y); }
669
670 template<typename _CharT, typename _Traits>
671 [[nodiscard]]
672 constexpr bool
673 operator!=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
674 basic_string_view<_CharT, _Traits> __y) noexcept
675 { return !(__x == __y); }
676
677 template<typename _CharT, typename _Traits>
678 [[nodiscard]]
679 constexpr bool
680 operator< (basic_string_view<_CharT, _Traits> __x,
681 basic_string_view<_CharT, _Traits> __y) noexcept
682 { return __x.compare(__y) < 0; }
683
684 template<typename _CharT, typename _Traits>
685 [[nodiscard]]
686 constexpr bool
687 operator< (basic_string_view<_CharT, _Traits> __x,
688 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
689 noexcept
690 { return __x.compare(__y) < 0; }
691
692 template<typename _CharT, typename _Traits>
693 [[nodiscard]]
694 constexpr bool
695 operator< (__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
696 basic_string_view<_CharT, _Traits> __y) noexcept
697 { return __x.compare(__y) < 0; }
698
699 template<typename _CharT, typename _Traits>
700 [[nodiscard]]
701 constexpr bool
702 operator> (basic_string_view<_CharT, _Traits> __x,
703 basic_string_view<_CharT, _Traits> __y) noexcept
704 { return __x.compare(__y) > 0; }
705
706 template<typename _CharT, typename _Traits>
707 [[nodiscard]]
708 constexpr bool
709 operator> (basic_string_view<_CharT, _Traits> __x,
710 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
711 noexcept
712 { return __x.compare(__y) > 0; }
713
714 template<typename _CharT, typename _Traits>
715 [[nodiscard]]
716 constexpr bool
717 operator> (__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
718 basic_string_view<_CharT, _Traits> __y) noexcept
719 { return __x.compare(__y) > 0; }
720
721 template<typename _CharT, typename _Traits>
722 [[nodiscard]]
723 constexpr bool
724 operator<=(basic_string_view<_CharT, _Traits> __x,
725 basic_string_view<_CharT, _Traits> __y) noexcept
726 { return __x.compare(__y) <= 0; }
727
728 template<typename _CharT, typename _Traits>
729 [[nodiscard]]
730 constexpr bool
731 operator<=(basic_string_view<_CharT, _Traits> __x,
732 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
733 noexcept
734 { return __x.compare(__y) <= 0; }
735
736 template<typename _CharT, typename _Traits>
737 [[nodiscard]]
738 constexpr bool
739 operator<=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
740 basic_string_view<_CharT, _Traits> __y) noexcept
741 { return __x.compare(__y) <= 0; }
742
743 template<typename _CharT, typename _Traits>
744 [[nodiscard]]
745 constexpr bool
746 operator>=(basic_string_view<_CharT, _Traits> __x,
747 basic_string_view<_CharT, _Traits> __y) noexcept
748 { return __x.compare(__y) >= 0; }
749
750 template<typename _CharT, typename _Traits>
751 [[nodiscard]]
752 constexpr bool
753 operator>=(basic_string_view<_CharT, _Traits> __x,
754 __type_identity_t<basic_string_view<_CharT, _Traits>> __y)
755 noexcept
756 { return __x.compare(__y) >= 0; }
757
758 template<typename _CharT, typename _Traits>
759 [[nodiscard]]
760 constexpr bool
761 operator>=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
762 basic_string_view<_CharT, _Traits> __y) noexcept
763 { return __x.compare(__y) >= 0; }
764#endif // three-way comparison
765
766#if _GLIBCXX_HOSTED
767 // [string.view.io], Inserters and extractors
768 template<typename _CharT, typename _Traits>
769 inline basic_ostream<_CharT, _Traits>&
770 operator<<(basic_ostream<_CharT, _Traits>& __os,
771 basic_string_view<_CharT,_Traits> __str)
772 { return __ostream_insert(__os, __str.data(), __str.size()); }
773#endif // HOSTED
774
775 // basic_string_view typedef names
776
777 using string_view = basic_string_view<char>;
778 using wstring_view = basic_string_view<wchar_t>;
779#ifdef _GLIBCXX_USE_CHAR8_T
780 using u8string_view = basic_string_view<char8_t>;
781#endif
782 using u16string_view = basic_string_view<char16_t>;
783 using u32string_view = basic_string_view<char32_t>;
784
785 // [string.view.hash], hash support:
786
787 template<typename _Tp>
788 struct hash;
789
790 template<>
791 struct hash<string_view>
792 : public __hash_base<size_t, string_view>
793 {
794 [[nodiscard]]
795 size_t
796 operator()(const string_view& __str) const noexcept
797 { return std::_Hash_impl::hash(__str.data(), __str.length()); }
798 };
799
800 template<>
801 struct __is_fast_hash<hash<string_view>> : std::false_type
802 { };
803
804 template<>
805 struct hash<wstring_view>
806 : public __hash_base<size_t, wstring_view>
807 {
808 [[nodiscard]]
809 size_t
810 operator()(const wstring_view& __s) const noexcept
811 { return std::_Hash_impl::hash(__s.data(),
812 __s.length() * sizeof(wchar_t)); }
813 };
814
815 template<>
816 struct __is_fast_hash<hash<wstring_view>> : std::false_type
817 { };
818
819#ifdef _GLIBCXX_USE_CHAR8_T
820 template<>
821 struct hash<u8string_view>
822 : public __hash_base<size_t, u8string_view>
823 {
824 [[nodiscard]]
825 size_t
826 operator()(const u8string_view& __str) const noexcept
827 { return std::_Hash_impl::hash(__str.data(), __str.length()); }
828 };
829
830 template<>
831 struct __is_fast_hash<hash<u8string_view>> : std::false_type
832 { };
833#endif
834
835 template<>
836 struct hash<u16string_view>
837 : public __hash_base<size_t, u16string_view>
838 {
839 [[nodiscard]]
840 size_t
841 operator()(const u16string_view& __s) const noexcept
842 { return std::_Hash_impl::hash(__s.data(),
843 __s.length() * sizeof(char16_t)); }
844 };
845
846 template<>
847 struct __is_fast_hash<hash<u16string_view>> : std::false_type
848 { };
849
850 template<>
851 struct hash<u32string_view>
852 : public __hash_base<size_t, u32string_view>
853 {
854 [[nodiscard]]
855 size_t
856 operator()(const u32string_view& __s) const noexcept
857 { return std::_Hash_impl::hash(__s.data(),
858 __s.length() * sizeof(char32_t)); }
859 };
860
861 template<>
862 struct __is_fast_hash<hash<u32string_view>> : std::false_type
863 { };
864
865 inline namespace literals
866 {
867 inline namespace string_view_literals
868 {
869#pragma GCC diagnostic push
870#pragma GCC diagnostic ignored "-Wliteral-suffix"
871 inline constexpr basic_string_view<char>
872 operator""sv(const char* __str, size_t __len) noexcept
873 { return basic_string_view<char>{__str, __len}; }
874
875 inline constexpr basic_string_view<wchar_t>
876 operator""sv(const wchar_t* __str, size_t __len) noexcept
877 { return basic_string_view<wchar_t>{__str, __len}; }
878
879#ifdef _GLIBCXX_USE_CHAR8_T
880 inline constexpr basic_string_view<char8_t>
881 operator""sv(const char8_t* __str, size_t __len) noexcept
882 { return basic_string_view<char8_t>{__str, __len}; }
883#endif
884
885 inline constexpr basic_string_view<char16_t>
886 operator""sv(const char16_t* __str, size_t __len) noexcept
887 { return basic_string_view<char16_t>{__str, __len}; }
888
889 inline constexpr basic_string_view<char32_t>
890 operator""sv(const char32_t* __str, size_t __len) noexcept
891 { return basic_string_view<char32_t>{__str, __len}; }
892
893#pragma GCC diagnostic pop
894 } // namespace string_literals
895 } // namespace literals
896
897#if __cpp_lib_concepts
898 namespace ranges
899 {
900 // Opt-in to borrowed_range concept
901 template<typename _CharT, typename _Traits>
902 inline constexpr bool
903 enable_borrowed_range<basic_string_view<_CharT, _Traits>> = true;
904
905 // Opt-in to view concept
906 template<typename _CharT, typename _Traits>
907 inline constexpr bool
908 enable_view<basic_string_view<_CharT, _Traits>> = true;
909 }
910#endif
911_GLIBCXX_END_NAMESPACE_VERSION
912} // namespace std
913
914#include <bits/string_view.tcc>
915
916#endif // C++17
917
918#endif // _GLIBCXX_STRING_VIEW
std::to_address
constexpr _Tp * to_address(_Tp *__ptr) noexcept
Obtain address referenced by a pointer to an object.
Definition ptr_traits.h:232
std::false_type
__bool_constant< false > false_type
The type used as a compile-time boolean with false value.
Definition type_traits:120
std::min
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition stl_algobase.h:234
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:1692
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:140
std::basic_ostream
Template class basic_ostream.
Definition ostream.h:67
std::basic_string_view
A non-owning reference to a string.
Definition string_view:109
std::hash
Primary class template hash.
Definition functional_hash.h:106