1// Components for manipulating non-owning sequences of characters -*- C++ -*-
2
3// Copyright (C) 2013-2019 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 <limits>
41#include <iosfwd>
42#include <bits/char_traits.h>
43#include <bits/functional_hash.h>
44#include <bits/range_access.h>
45
46namespace std _GLIBCXX_VISIBILITY(default)
47{
48_GLIBCXX_BEGIN_NAMESPACE_VERSION
49
50#define __cpp_lib_string_view 201803
51
52 // Helper for basic_string and basic_string_view members.
53 constexpr size_t
54 __sv_check(size_t __size, size_t __pos, const char* __s)
55 {
56 if (__pos > __size)
57 __throw_out_of_range_fmt(__N("%s: __pos (which is %zu) > __size "
58 "(which is %zu)"), __s, __pos, __size);
59 return __pos;
60 }
61
62 // Helper for basic_string members.
63 // NB: __sv_limit doesn't check for a bad __pos value.
64 constexpr size_t
65 __sv_limit(size_t __size, size_t __pos, size_t __off) noexcept
66 {
67 const bool __testoff = __off < __size - __pos;
68 return __testoff ? __off : __size - __pos;
69 }
70
71 /**
72 * @class basic_string_view <string_view>
73 * @brief A non-owning reference to a string.
74 *
75 * @ingroup strings
76 * @ingroup sequences
77 *
78 * @tparam _CharT Type of character
79 * @tparam _Traits Traits for character type, defaults to
80 * char_traits<_CharT>.
81 *
82 * A basic_string_view looks like this:
83 *
84 * @code
85 * _CharT* _M_str
86 * size_t _M_len
87 * @endcode
88 */
89 template<typename _CharT, typename _Traits = std::char_traits<_CharT>>
90 class basic_string_view
91 {
92 static_assert(!is_array_v<_CharT>);
93 static_assert(is_trivial_v<_CharT> && is_standard_layout_v<_CharT>);
94 static_assert(is_same_v<_CharT, typename _Traits::char_type>);
95
96 public:
97
98 // types
99 using traits_type = _Traits;
100 using value_type = _CharT;
101 using pointer = value_type*;
102 using const_pointer = const value_type*;
103 using reference = value_type&;
104 using const_reference = const value_type&;
105 using const_iterator = const value_type*;
106 using iterator = const_iterator;
107 using const_reverse_iterator = std::reverse_iterator<const_iterator>;
108 using reverse_iterator = const_reverse_iterator;
109 using size_type = size_t;
110 using difference_type = ptrdiff_t;
111 static constexpr size_type npos = size_type(-1);
112
113 // [string.view.cons], construction and assignment
114
115 constexpr
116 basic_string_view() noexcept
117 : _M_len{0}, _M_str{nullptr}
118 { }
119
120 constexpr basic_string_view(const basic_string_view&) noexcept = default;
121
122 __attribute__((__nonnull__)) constexpr
123 basic_string_view(const _CharT* __str) noexcept
124 : _M_len{traits_type::length(__str)},
125 _M_str{__str}
126 { }
127
128 constexpr
129 basic_string_view(const _CharT* __str, size_type __len) noexcept
130 : _M_len{__len}, _M_str{__str}
131 { }
132
133 constexpr basic_string_view&
134 operator=(const basic_string_view&) noexcept = default;
135
136 // [string.view.iterators], iterator support
137
138 constexpr const_iterator
139 begin() const noexcept
140 { return this->_M_str; }
141
142 constexpr const_iterator
143 end() const noexcept
144 { return this->_M_str + this->_M_len; }
145
146 constexpr const_iterator
147 cbegin() const noexcept
148 { return this->_M_str; }
149
150 constexpr const_iterator
151 cend() const noexcept
152 { return this->_M_str + this->_M_len; }
153
154 constexpr const_reverse_iterator
155 rbegin() const noexcept
156 { return const_reverse_iterator(this->end()); }
157
158 constexpr const_reverse_iterator
159 rend() const noexcept
160 { return const_reverse_iterator(this->begin()); }
161
162 constexpr const_reverse_iterator
163 crbegin() const noexcept
164 { return const_reverse_iterator(this->end()); }
165
166 constexpr const_reverse_iterator
167 crend() const noexcept
168 { return const_reverse_iterator(this->begin()); }
169
170 // [string.view.capacity], capacity
171
172 constexpr size_type
173 size() const noexcept
174 { return this->_M_len; }
175
176 constexpr size_type
177 length() const noexcept
178 { return _M_len; }
179
180 constexpr size_type
181 max_size() const noexcept
182 {
183 return (npos - sizeof(size_type) - sizeof(void*))
184 / sizeof(value_type) / 4;
185 }
186
187 [[nodiscard]] constexpr bool
188 empty() const noexcept
189 { return this->_M_len == 0; }
190
191 // [string.view.access], element access
192
193 constexpr const_reference
194 operator[](size_type __pos) const noexcept
195 {
196 __glibcxx_assert(__pos < this->_M_len);
197 return *(this->_M_str + __pos);
198 }
199
200 constexpr const_reference
201 at(size_type __pos) const
202 {
203 if (__pos >= _M_len)
204 __throw_out_of_range_fmt(__N("basic_string_view::at: __pos "
205 "(which is %zu) >= this->size() "
206 "(which is %zu)"), __pos, this->size());
207 return *(this->_M_str + __pos);
208 }
209
210 constexpr const_reference
211 front() const noexcept
212 {
213 __glibcxx_assert(this->_M_len > 0);
214 return *this->_M_str;
215 }
216
217 constexpr const_reference
218 back() const noexcept
219 {
220 __glibcxx_assert(this->_M_len > 0);
221 return *(this->_M_str + this->_M_len - 1);
222 }
223
224 constexpr const_pointer
225 data() const noexcept
226 { return this->_M_str; }
227
228 // [string.view.modifiers], modifiers:
229
230 constexpr void
231 remove_prefix(size_type __n) noexcept
232 {
233 __glibcxx_assert(this->_M_len >= __n);
234 this->_M_str += __n;
235 this->_M_len -= __n;
236 }
237
238 constexpr void
239 remove_suffix(size_type __n) noexcept
240 { this->_M_len -= __n; }
241
242 constexpr void
243 swap(basic_string_view& __sv) noexcept
244 {
245 auto __tmp = *this;
246 *this = __sv;
247 __sv = __tmp;
248 }
249
250 // [string.view.ops], string operations:
251
252 size_type
253 copy(_CharT* __str, size_type __n, size_type __pos = 0) const
254 {
255 __glibcxx_requires_string_len(__str, __n);
256 __pos = std::__sv_check(size: size(), __pos, s: "basic_string_view::copy");
257 const size_type __rlen = std::min(a: __n, b: _M_len - __pos);
258 // _GLIBCXX_RESOLVE_LIB_DEFECTS
259 // 2777. basic_string_view::copy should use char_traits::copy
260 traits_type::copy(__str, data() + __pos, __rlen);
261 return __rlen;
262 }
263
264 constexpr basic_string_view
265 substr(size_type __pos = 0, size_type __n = npos) const noexcept(false)
266 {
267 __pos = std::__sv_check(size: size(), __pos, s: "basic_string_view::substr");
268 const size_type __rlen = std::min(a: __n, b: _M_len - __pos);
269 return basic_string_view{_M_str + __pos, __rlen};
270 }
271
272 constexpr int
273 compare(basic_string_view __str) const noexcept
274 {
275 const size_type __rlen = std::min(this->_M_len, __str._M_len);
276 int __ret = traits_type::compare(this->_M_str, __str._M_str, __rlen);
277 if (__ret == 0)
278 __ret = _S_compare(n1: this->_M_len, n2: __str._M_len);
279 return __ret;
280 }
281
282 constexpr int
283 compare(size_type __pos1, size_type __n1, basic_string_view __str) const
284 { return this->substr(__pos1, __n1).compare(__str); }
285
286 constexpr int
287 compare(size_type __pos1, size_type __n1,
288 basic_string_view __str, size_type __pos2, size_type __n2) const
289 {
290 return this->substr(__pos1, __n1).compare(__str.substr(__pos2, __n2));
291 }
292
293 __attribute__((__nonnull__)) constexpr int
294 compare(const _CharT* __str) const noexcept
295 { return this->compare(basic_string_view{__str}); }
296
297 __attribute__((__nonnull__)) constexpr int
298 compare(size_type __pos1, size_type __n1, const _CharT* __str) const
299 { return this->substr(__pos1, __n1).compare(basic_string_view{__str}); }
300
301 constexpr int
302 compare(size_type __pos1, size_type __n1,
303 const _CharT* __str, size_type __n2) const noexcept(false)
304 {
305 return this->substr(__pos1, __n1)
306 .compare(basic_string_view(__str, __n2));
307 }
308
309#if __cplusplus > 201703L
310#define __cpp_lib_starts_ends_with 201711L
311 constexpr bool
312 starts_with(basic_string_view __x) const noexcept
313 { return this->substr(0, __x.size()) == __x; }
314
315 constexpr bool
316 starts_with(_CharT __x) const noexcept
317 { return !this->empty() && traits_type::eq(this->front(), __x); }
318
319 constexpr bool
320 starts_with(const _CharT* __x) const noexcept
321 { return this->starts_with(basic_string_view(__x)); }
322
323 constexpr bool
324 ends_with(basic_string_view __x) const noexcept
325 {
326 return this->size() >= __x.size()
327 && this->compare(this->size() - __x.size(), npos, __x) == 0;
328 }
329
330 constexpr bool
331 ends_with(_CharT __x) const noexcept
332 { return !this->empty() && traits_type::eq(this->back(), __x); }
333
334 constexpr bool
335 ends_with(const _CharT* __x) const noexcept
336 { return this->ends_with(basic_string_view(__x)); }
337#endif // C++20
338
339 // [string.view.find], searching
340
341 constexpr size_type
342 find(basic_string_view __str, size_type __pos = 0) const noexcept
343 { return this->find(__str._M_str, __pos, __str._M_len); }
344
345 constexpr size_type
346 find(_CharT __c, size_type __pos = 0) const noexcept;
347
348 constexpr size_type
349 find(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
350
351 __attribute__((__nonnull__)) constexpr size_type
352 find(const _CharT* __str, size_type __pos = 0) const noexcept
353 { return this->find(__str, __pos, traits_type::length(__str)); }
354
355 constexpr size_type
356 rfind(basic_string_view __str, size_type __pos = npos) const noexcept
357 { return this->rfind(__str._M_str, __pos, __str._M_len); }
358
359 constexpr size_type
360 rfind(_CharT __c, size_type __pos = npos) const noexcept;
361
362 constexpr size_type
363 rfind(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
364
365 __attribute__((__nonnull__)) constexpr size_type
366 rfind(const _CharT* __str, size_type __pos = npos) const noexcept
367 { return this->rfind(__str, __pos, traits_type::length(__str)); }
368
369 constexpr size_type
370 find_first_of(basic_string_view __str, size_type __pos = 0) const noexcept
371 { return this->find_first_of(__str._M_str, __pos, __str._M_len); }
372
373 constexpr size_type
374 find_first_of(_CharT __c, size_type __pos = 0) const noexcept
375 { return this->find(__c, __pos); }
376
377 constexpr size_type
378 find_first_of(const _CharT* __str, size_type __pos,
379 size_type __n) const noexcept;
380
381 __attribute__((__nonnull__)) constexpr size_type
382 find_first_of(const _CharT* __str, size_type __pos = 0) const noexcept
383 { return this->find_first_of(__str, __pos, traits_type::length(__str)); }
384
385 constexpr size_type
386 find_last_of(basic_string_view __str,
387 size_type __pos = npos) const noexcept
388 { return this->find_last_of(__str._M_str, __pos, __str._M_len); }
389
390 constexpr size_type
391 find_last_of(_CharT __c, size_type __pos=npos) const noexcept
392 { return this->rfind(__c, __pos); }
393
394 constexpr size_type
395 find_last_of(const _CharT* __str, size_type __pos,
396 size_type __n) const noexcept;
397
398 __attribute__((__nonnull__)) constexpr size_type
399 find_last_of(const _CharT* __str, size_type __pos = npos) const noexcept
400 { return this->find_last_of(__str, __pos, traits_type::length(__str)); }
401
402 constexpr size_type
403 find_first_not_of(basic_string_view __str,
404 size_type __pos = 0) const noexcept
405 { return this->find_first_not_of(__str._M_str, __pos, __str._M_len); }
406
407 constexpr size_type
408 find_first_not_of(_CharT __c, size_type __pos = 0) const noexcept;
409
410 constexpr size_type
411 find_first_not_of(const _CharT* __str,
412 size_type __pos, size_type __n) const noexcept;
413
414 __attribute__((__nonnull__)) constexpr size_type
415 find_first_not_of(const _CharT* __str, size_type __pos = 0) const noexcept
416 {
417 return this->find_first_not_of(__str, __pos,
418 traits_type::length(__str));
419 }
420
421 constexpr size_type
422 find_last_not_of(basic_string_view __str,
423 size_type __pos = npos) const noexcept
424 { return this->find_last_not_of(__str._M_str, __pos, __str._M_len); }
425
426 constexpr size_type
427 find_last_not_of(_CharT __c, size_type __pos = npos) const noexcept;
428
429 constexpr size_type
430 find_last_not_of(const _CharT* __str,
431 size_type __pos, size_type __n) const noexcept;
432
433 __attribute__((__nonnull__)) constexpr size_type
434 find_last_not_of(const _CharT* __str,
435 size_type __pos = npos) const noexcept
436 {
437 return this->find_last_not_of(__str, __pos,
438 traits_type::length(__str));
439 }
440
441 private:
442
443 static constexpr int
444 _S_compare(size_type __n1, size_type __n2) noexcept
445 {
446 const difference_type __diff = __n1 - __n2;
447 if (__diff > std::numeric_limits<int>::max())
448 return std::numeric_limits<int>::max();
449 if (__diff < std::numeric_limits<int>::min())
450 return std::numeric_limits<int>::min();
451 return static_cast<int>(__diff);
452 }
453
454 size_t _M_len;
455 const _CharT* _M_str;
456 };
457
458 // [string.view.comparison], non-member basic_string_view comparison function
459
460 namespace __detail
461 {
462 // Identity transform to create a non-deduced context, so that only one
463 // argument participates in template argument deduction and the other
464 // argument gets implicitly converted to the deduced type. See n3766.html.
465 template<typename _Tp>
466 using __idt = common_type_t<_Tp>;
467 }
468
469 template<typename _CharT, typename _Traits>
470 constexpr bool
471 operator==(basic_string_view<_CharT, _Traits> __x,
472 basic_string_view<_CharT, _Traits> __y) noexcept
473 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
474
475 template<typename _CharT, typename _Traits>
476 constexpr bool
477 operator==(basic_string_view<_CharT, _Traits> __x,
478 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
479 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
480
481 template<typename _CharT, typename _Traits>
482 constexpr bool
483 operator==(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
484 basic_string_view<_CharT, _Traits> __y) noexcept
485 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
486
487 template<typename _CharT, typename _Traits>
488 constexpr bool
489 operator!=(basic_string_view<_CharT, _Traits> __x,
490 basic_string_view<_CharT, _Traits> __y) noexcept
491 { return !(__x == __y); }
492
493 template<typename _CharT, typename _Traits>
494 constexpr bool
495 operator!=(basic_string_view<_CharT, _Traits> __x,
496 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
497 { return !(__x == __y); }
498
499 template<typename _CharT, typename _Traits>
500 constexpr bool
501 operator!=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
502 basic_string_view<_CharT, _Traits> __y) noexcept
503 { return !(__x == __y); }
504
505 template<typename _CharT, typename _Traits>
506 constexpr bool
507 operator< (basic_string_view<_CharT, _Traits> __x,
508 basic_string_view<_CharT, _Traits> __y) noexcept
509 { return __x.compare(__y) < 0; }
510
511 template<typename _CharT, typename _Traits>
512 constexpr bool
513 operator< (basic_string_view<_CharT, _Traits> __x,
514 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
515 { return __x.compare(__y) < 0; }
516
517 template<typename _CharT, typename _Traits>
518 constexpr bool
519 operator< (__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
520 basic_string_view<_CharT, _Traits> __y) noexcept
521 { return __x.compare(__y) < 0; }
522
523 template<typename _CharT, typename _Traits>
524 constexpr bool
525 operator> (basic_string_view<_CharT, _Traits> __x,
526 basic_string_view<_CharT, _Traits> __y) noexcept
527 { return __x.compare(__y) > 0; }
528
529 template<typename _CharT, typename _Traits>
530 constexpr bool
531 operator> (basic_string_view<_CharT, _Traits> __x,
532 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
533 { return __x.compare(__y) > 0; }
534
535 template<typename _CharT, typename _Traits>
536 constexpr bool
537 operator> (__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
538 basic_string_view<_CharT, _Traits> __y) noexcept
539 { return __x.compare(__y) > 0; }
540
541 template<typename _CharT, typename _Traits>
542 constexpr bool
543 operator<=(basic_string_view<_CharT, _Traits> __x,
544 basic_string_view<_CharT, _Traits> __y) noexcept
545 { return __x.compare(__y) <= 0; }
546
547 template<typename _CharT, typename _Traits>
548 constexpr bool
549 operator<=(basic_string_view<_CharT, _Traits> __x,
550 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
551 { return __x.compare(__y) <= 0; }
552
553 template<typename _CharT, typename _Traits>
554 constexpr bool
555 operator<=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
556 basic_string_view<_CharT, _Traits> __y) noexcept
557 { return __x.compare(__y) <= 0; }
558
559 template<typename _CharT, typename _Traits>
560 constexpr bool
561 operator>=(basic_string_view<_CharT, _Traits> __x,
562 basic_string_view<_CharT, _Traits> __y) noexcept
563 { return __x.compare(__y) >= 0; }
564
565 template<typename _CharT, typename _Traits>
566 constexpr bool
567 operator>=(basic_string_view<_CharT, _Traits> __x,
568 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
569 { return __x.compare(__y) >= 0; }
570
571 template<typename _CharT, typename _Traits>
572 constexpr bool
573 operator>=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
574 basic_string_view<_CharT, _Traits> __y) noexcept
575 { return __x.compare(__y) >= 0; }
576
577 // [string.view.io], Inserters and extractors
578 template<typename _CharT, typename _Traits>
579 inline basic_ostream<_CharT, _Traits>&
580 operator<<(basic_ostream<_CharT, _Traits>& __os,
581 basic_string_view<_CharT,_Traits> __str)
582 { return __ostream_insert(__os, __str.data(), __str.size()); }
583
584
585 // basic_string_view typedef names
586
587 using string_view = basic_string_view<char>;
588#ifdef _GLIBCXX_USE_WCHAR_T
589 using wstring_view = basic_string_view<wchar_t>;
590#endif
591#ifdef _GLIBCXX_USE_CHAR8_T
592 using u8string_view = basic_string_view<char8_t>;
593#endif
594 using u16string_view = basic_string_view<char16_t>;
595 using u32string_view = basic_string_view<char32_t>;
596
597 // [string.view.hash], hash support:
598
599 template<typename _Tp>
600 struct hash;
601
602 template<>
603 struct hash<string_view>
604 : public __hash_base<size_t, string_view>
605 {
606 size_t
607 operator()(const string_view& __str) const noexcept
608 { return std::_Hash_impl::hash(ptr: __str.data(), clength: __str.length()); }
609 };
610
611 template<>
612 struct __is_fast_hash<hash<string_view>> : std::false_type
613 { };
614
615#ifdef _GLIBCXX_USE_WCHAR_T
616 template<>
617 struct hash<wstring_view>
618 : public __hash_base<size_t, wstring_view>
619 {
620 size_t
621 operator()(const wstring_view& __s) const noexcept
622 { return std::_Hash_impl::hash(ptr: __s.data(),
623 clength: __s.length() * sizeof(wchar_t)); }
624 };
625
626 template<>
627 struct __is_fast_hash<hash<wstring_view>> : std::false_type
628 { };
629#endif
630
631#ifdef _GLIBCXX_USE_CHAR8_T
632 template<>
633 struct hash<u8string_view>
634 : public __hash_base<size_t, u8string_view>
635 {
636 size_t
637 operator()(const u8string_view& __str) const noexcept
638 { return std::_Hash_impl::hash(__str.data(), __str.length()); }
639 };
640
641 template<>
642 struct __is_fast_hash<hash<u8string_view>> : std::false_type
643 { };
644#endif
645
646 template<>
647 struct hash<u16string_view>
648 : public __hash_base<size_t, u16string_view>
649 {
650 size_t
651 operator()(const u16string_view& __s) const noexcept
652 { return std::_Hash_impl::hash(ptr: __s.data(),
653 clength: __s.length() * sizeof(char16_t)); }
654 };
655
656 template<>
657 struct __is_fast_hash<hash<u16string_view>> : std::false_type
658 { };
659
660 template<>
661 struct hash<u32string_view>
662 : public __hash_base<size_t, u32string_view>
663 {
664 size_t
665 operator()(const u32string_view& __s) const noexcept
666 { return std::_Hash_impl::hash(ptr: __s.data(),
667 clength: __s.length() * sizeof(char32_t)); }
668 };
669
670 template<>
671 struct __is_fast_hash<hash<u32string_view>> : std::false_type
672 { };
673
674 inline namespace literals
675 {
676 inline namespace string_view_literals
677 {
678#pragma GCC diagnostic push
679#pragma GCC diagnostic ignored "-Wliteral-suffix"
680 inline constexpr basic_string_view<char>
681 operator""sv(const char* __str, size_t __len) noexcept
682 { return basic_string_view<char>{__str, __len}; }
683
684#ifdef _GLIBCXX_USE_WCHAR_T
685 inline constexpr basic_string_view<wchar_t>
686 operator""sv(const wchar_t* __str, size_t __len) noexcept
687 { return basic_string_view<wchar_t>{__str, __len}; }
688#endif
689
690#ifdef _GLIBCXX_USE_CHAR8_T
691 inline constexpr basic_string_view<char8_t>
692 operator""sv(const char8_t* __str, size_t __len) noexcept
693 { return basic_string_view<char8_t>{__str, __len}; }
694#endif
695
696 inline constexpr basic_string_view<char16_t>
697 operator""sv(const char16_t* __str, size_t __len) noexcept
698 { return basic_string_view<char16_t>{__str, __len}; }
699
700 inline constexpr basic_string_view<char32_t>
701 operator""sv(const char32_t* __str, size_t __len) noexcept
702 { return basic_string_view<char32_t>{__str, __len}; }
703
704#pragma GCC diagnostic pop
705 } // namespace string_literals
706 } // namespace literals
707
708_GLIBCXX_END_NAMESPACE_VERSION
709} // namespace std
710
711#include <bits/string_view.tcc>
712
713#endif // __cplusplus <= 201402L
714
715#endif // _GLIBCXX_EXPERIMENTAL_STRING_VIEW
716