libstdc++
string_view
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1// Components for manipulating non-owning sequences of characters -*- C++ -*-
2
3// Copyright (C) 2013-2017 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 experimental/string_view
26 * This is a TS C++ Library header.
27 */
28
29//
30// N3762 basic_string_view library
31//
32
33#ifndef _GLIBCXX_EXPERIMENTAL_STRING_VIEW
34#define _GLIBCXX_EXPERIMENTAL_STRING_VIEW 1
35
36#pragma GCC system_header
37
38#if __cplusplus <= 201103L
39# include <bits/c++14_warning.h>
40#else
41
42#include <string>
43#include <limits>
44#include <experimental/bits/lfts_config.h>
45
46namespace std _GLIBCXX_VISIBILITY(default)
47{
48namespace experimental
49{
50inline namespace fundamentals_v1
51{
52_GLIBCXX_BEGIN_NAMESPACE_VERSION
53
54#define __cpp_lib_experimental_string_view 201411
55
56 /**
57 * @class basic_string_view <experimental/string_view>
58 * @brief A non-owning reference to a string.
59 *
60 * @ingroup strings
61 * @ingroup sequences
62 * @ingroup experimental
63 *
64 * @tparam _CharT Type of character
65 * @tparam _Traits Traits for character type, defaults to
66 * char_traits<_CharT>.
67 *
68 * A basic_string_view looks like this:
69 *
70 * @code
71 * _CharT* _M_str
72 * size_t _M_len
73 * @endcode
74 */
75 template<typename _CharT, typename _Traits = std::char_traits<_CharT>>
76 class basic_string_view
77 {
78 public:
79
80 // types
81 using traits_type = _Traits;
82 using value_type = _CharT;
83 using pointer = const _CharT*;
84 using const_pointer = const _CharT*;
85 using reference = const _CharT&;
86 using const_reference = const _CharT&;
87 using const_iterator = const _CharT*;
88 using iterator = const_iterator;
89 using const_reverse_iterator = std::reverse_iterator<const_iterator>;
90 using reverse_iterator = const_reverse_iterator;
91 using size_type = size_t;
92 using difference_type = ptrdiff_t;
93 static constexpr size_type npos = size_type(-1);
94
95 // [string.view.cons], construct/copy
96
97 constexpr
98 basic_string_view() noexcept
99 : _M_len{0}, _M_str{nullptr}
100 { }
101
102 constexpr basic_string_view(const basic_string_view&) noexcept = default;
103
104 template<typename _Allocator>
105 basic_string_view(const basic_string<_CharT, _Traits,
106 _Allocator>& __str) noexcept
107 : _M_len{__str.length()}, _M_str{__str.data()}
108 { }
109
110 constexpr basic_string_view(const _CharT* __str)
111 : _M_len{__str == nullptr ? 0 : traits_type::length(__str)},
112 _M_str{__str}
113 { }
114
115 constexpr basic_string_view(const _CharT* __str, size_type __len)
116 : _M_len{__len},
117 _M_str{__str}
118 { }
119
120 basic_string_view&
121 operator=(const basic_string_view&) noexcept = default;
122
123 // [string.view.iterators], iterators
124
125 constexpr const_iterator
126 begin() const noexcept
127 { return this->_M_str; }
128
129 constexpr const_iterator
130 end() const noexcept
131 { return this->_M_str + this->_M_len; }
132
133 constexpr const_iterator
134 cbegin() const noexcept
135 { return this->_M_str; }
136
137 constexpr const_iterator
138 cend() const noexcept
139 { return this->_M_str + this->_M_len; }
140
141 const_reverse_iterator
142 rbegin() const noexcept
143 { return const_reverse_iterator(this->end()); }
144
145 const_reverse_iterator
146 rend() const noexcept
147 { return const_reverse_iterator(this->begin()); }
148
149 const_reverse_iterator
150 crbegin() const noexcept
151 { return const_reverse_iterator(this->end()); }
152
153 const_reverse_iterator
154 crend() const noexcept
155 { return const_reverse_iterator(this->begin()); }
156
157 // [string.view.capacity], capacity
158
159 constexpr size_type
160 size() const noexcept
161 { return this->_M_len; }
162
163 constexpr size_type
164 length() const noexcept
165 { return _M_len; }
166
167 constexpr size_type
168 max_size() const noexcept
169 {
170 return (npos - sizeof(size_type) - sizeof(void*))
171 / sizeof(value_type) / 4;
172 }
173
174 constexpr bool
175 empty() const noexcept
176 { return this->_M_len == 0; }
177
178 // [string.view.access], element access
179
180 constexpr const _CharT&
181 operator[](size_type __pos) const
182 {
183 // TODO: Assert to restore in a way compatible with the constexpr.
184 // __glibcxx_assert(__pos < this->_M_len);
185 return *(this->_M_str + __pos);
186 }
187
188 constexpr const _CharT&
189 at(size_type __pos) const
190 {
191 return __pos < this->_M_len
192 ? *(this->_M_str + __pos)
193 : (__throw_out_of_range_fmt(__N("basic_string_view::at: __pos "
194 "(which is %zu) >= this->size() "
195 "(which is %zu)"),
196 __pos, this->size()),
197 *this->_M_str);
198 }
199
200 constexpr const _CharT&
201 front() const
202 {
203 // TODO: Assert to restore in a way compatible with the constexpr.
204 // __glibcxx_assert(this->_M_len > 0);
205 return *this->_M_str;
206 }
207
208 constexpr const _CharT&
209 back() const
210 {
211 // TODO: Assert to restore in a way compatible with the constexpr.
212 // __glibcxx_assert(this->_M_len > 0);
213 return *(this->_M_str + this->_M_len - 1);
214 }
215
216 constexpr const _CharT*
217 data() const noexcept
218 { return this->_M_str; }
219
220 // [string.view.modifiers], modifiers:
221
222 constexpr void
223 remove_prefix(size_type __n)
224 {
225 __glibcxx_assert(this->_M_len >= __n);
226 this->_M_str += __n;
227 this->_M_len -= __n;
228 }
229
230 constexpr void
231 remove_suffix(size_type __n)
232 { this->_M_len -= __n; }
233
234 constexpr void
235 swap(basic_string_view& __sv) noexcept
236 {
237 auto __tmp = *this;
238 *this = __sv;
239 __sv = __tmp;
240 }
241
242
243 // [string.view.ops], string operations:
244
245 template<typename _Allocator>
246 explicit operator basic_string<_CharT, _Traits, _Allocator>() const
247 {
248 return { this->_M_str, this->_M_len };
249 }
250
251 template<typename _Allocator = std::allocator<_CharT>>
252 basic_string<_CharT, _Traits, _Allocator>
253 to_string(const _Allocator& __alloc = _Allocator()) const
254 {
255 return { this->_M_str, this->_M_len, __alloc };
256 }
257
258 size_type
259 copy(_CharT* __str, size_type __n, size_type __pos = 0) const
260 {
261 __glibcxx_requires_string_len(__str, __n);
262 if (__pos > this->_M_len)
263 __throw_out_of_range_fmt(__N("basic_string_view::copy: __pos "
264 "(which is %zu) > this->size() "
265 "(which is %zu)"),
266 __pos, this->size());
267 size_type __rlen{std::min(__n, size_type{this->_M_len - __pos})};
268 for (auto __begin = this->_M_str + __pos,
269 __end = __begin + __rlen; __begin != __end;)
270 *__str++ = *__begin++;
271 return __rlen;
272 }
273
274
275 // [string.view.ops], string operations:
276
277 constexpr basic_string_view
278 substr(size_type __pos, size_type __n=npos) const
279 {
280 return __pos <= this->_M_len
281 ? basic_string_view{this->_M_str + __pos,
282 std::min(__n, size_type{this->_M_len - __pos})}
283 : (__throw_out_of_range_fmt(__N("basic_string_view::substr: __pos "
284 "(which is %zu) > this->size() "
285 "(which is %zu)"),
286 __pos, this->size()), basic_string_view{});
287 }
288
289 constexpr int
290 compare(basic_string_view __str) const noexcept
291 {
292 int __ret = traits_type::compare(this->_M_str, __str._M_str,
293 std::min(this->_M_len, __str._M_len));
294 if (__ret == 0)
295 __ret = _S_compare(this->_M_len, __str._M_len);
296 return __ret;
297 }
298
299 constexpr int
300 compare(size_type __pos1, size_type __n1, basic_string_view __str) const
301 { return this->substr(__pos1, __n1).compare(__str); }
302
303 constexpr int
304 compare(size_type __pos1, size_type __n1,
305 basic_string_view __str, size_type __pos2, size_type __n2) const
306 { return this->substr(__pos1, __n1).compare(__str.substr(__pos2, __n2)); }
307
308 constexpr int
309 compare(const _CharT* __str) const noexcept
310 { return this->compare(basic_string_view{__str}); }
311
312 constexpr int
313 compare(size_type __pos1, size_type __n1, const _CharT* __str) const
314 { return this->substr(__pos1, __n1).compare(basic_string_view{__str}); }
315
316 constexpr int
317 compare(size_type __pos1, size_type __n1,
318 const _CharT* __str, size_type __n2) const
319 {
320 return this->substr(__pos1, __n1)
321 .compare(basic_string_view(__str, __n2));
322 }
323
324 constexpr size_type
325 find(basic_string_view __str, size_type __pos = 0) const noexcept
326 { return this->find(__str._M_str, __pos, __str._M_len); }
327
328 constexpr size_type
329 find(_CharT __c, size_type __pos=0) const noexcept;
330
331 constexpr size_type
332 find(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
333
334 constexpr size_type
335 find(const _CharT* __str, size_type __pos=0) const noexcept
336 { return this->find(__str, __pos, traits_type::length(__str)); }
337
338 constexpr size_type
339 rfind(basic_string_view __str, size_type __pos = npos) const noexcept
340 { return this->rfind(__str._M_str, __pos, __str._M_len); }
341
342 constexpr size_type
343 rfind(_CharT __c, size_type __pos = npos) const noexcept;
344
345 constexpr size_type
346 rfind(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
347
348 constexpr size_type
349 rfind(const _CharT* __str, size_type __pos = npos) const noexcept
350 { return this->rfind(__str, __pos, traits_type::length(__str)); }
351
352 constexpr size_type
353 find_first_of(basic_string_view __str, size_type __pos = 0) const noexcept
354 { return this->find_first_of(__str._M_str, __pos, __str._M_len); }
355
356 constexpr size_type
357 find_first_of(_CharT __c, size_type __pos = 0) const noexcept
358 { return this->find(__c, __pos); }
359
360 constexpr size_type
361 find_first_of(const _CharT* __str, size_type __pos, size_type __n) const;
362
363 constexpr size_type
364 find_first_of(const _CharT* __str, size_type __pos = 0) const noexcept
365 { return this->find_first_of(__str, __pos, traits_type::length(__str)); }
366
367 constexpr size_type
368 find_last_of(basic_string_view __str,
369 size_type __pos = npos) const noexcept
370 { return this->find_last_of(__str._M_str, __pos, __str._M_len); }
371
372 constexpr size_type
373 find_last_of(_CharT __c, size_type __pos=npos) const noexcept
374 { return this->rfind(__c, __pos); }
375
376 constexpr size_type
377 find_last_of(const _CharT* __str, size_type __pos, size_type __n) const;
378
379 constexpr size_type
380 find_last_of(const _CharT* __str, size_type __pos = npos) const noexcept
381 { return this->find_last_of(__str, __pos, traits_type::length(__str)); }
382
383 constexpr size_type
384 find_first_not_of(basic_string_view __str,
385 size_type __pos = 0) const noexcept
386 { return this->find_first_not_of(__str._M_str, __pos, __str._M_len); }
387
388 constexpr size_type
389 find_first_not_of(_CharT __c, size_type __pos = 0) const noexcept;
390
391 constexpr size_type
392 find_first_not_of(const _CharT* __str,
393 size_type __pos, size_type __n) const;
394
395 constexpr size_type
396 find_first_not_of(const _CharT* __str, size_type __pos = 0) const noexcept
397 {
398 return this->find_first_not_of(__str, __pos,
399 traits_type::length(__str));
400 }
401
402 constexpr size_type
403 find_last_not_of(basic_string_view __str,
404 size_type __pos = npos) const noexcept
405 { return this->find_last_not_of(__str._M_str, __pos, __str._M_len); }
406
407 constexpr size_type
408 find_last_not_of(_CharT __c, size_type __pos = npos) const noexcept;
409
410 constexpr size_type
411 find_last_not_of(const _CharT* __str,
412 size_type __pos, size_type __n) const;
413
414 constexpr size_type
415 find_last_not_of(const _CharT* __str,
416 size_type __pos = npos) const noexcept
417 {
418 return this->find_last_not_of(__str, __pos,
419 traits_type::length(__str));
420 }
421
422 private:
423
424 static constexpr int
425 _S_compare(size_type __n1, size_type __n2) noexcept
426 {
427 return difference_type{__n1 - __n2} > std::numeric_limits<int>::max()
428 ? std::numeric_limits<int>::max()
429 : difference_type{__n1 - __n2} < std::numeric_limits<int>::min()
430 ? std::numeric_limits<int>::min()
431 : static_cast<int>(difference_type{__n1 - __n2});
432 }
433
434 size_t _M_len;
435 const _CharT* _M_str;
436 };
437
438_GLIBCXX_END_NAMESPACE_VERSION
439
440 // [string.view.comparison], non-member basic_string_view comparison functions
441
442 namespace __detail
443 {
444_GLIBCXX_BEGIN_NAMESPACE_VERSION
445 // Identity transform to create a non-deduced context, so that only one
446 // argument participates in template argument deduction and the other
447 // argument gets implicitly converted to the deduced type. See n3766.html.
448 template<typename _Tp>
449 using __idt = common_type_t<_Tp>;
450_GLIBCXX_END_NAMESPACE_VERSION
451 }
452
453_GLIBCXX_BEGIN_NAMESPACE_VERSION
454
455 template<typename _CharT, typename _Traits>
456 constexpr bool
457 operator==(basic_string_view<_CharT, _Traits> __x,
458 basic_string_view<_CharT, _Traits> __y) noexcept
459 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
460
461 template<typename _CharT, typename _Traits>
462 constexpr bool
463 operator==(basic_string_view<_CharT, _Traits> __x,
464 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
465 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
466
467 template<typename _CharT, typename _Traits>
468 constexpr bool
469 operator==(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
470 basic_string_view<_CharT, _Traits> __y) noexcept
471 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
472
473 template<typename _CharT, typename _Traits>
474 constexpr bool
475 operator!=(basic_string_view<_CharT, _Traits> __x,
476 basic_string_view<_CharT, _Traits> __y) noexcept
477 { return !(__x == __y); }
478
479 template<typename _CharT, typename _Traits>
480 constexpr bool
481 operator!=(basic_string_view<_CharT, _Traits> __x,
482 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
483 { return !(__x == __y); }
484
485 template<typename _CharT, typename _Traits>
486 constexpr bool
487 operator!=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
488 basic_string_view<_CharT, _Traits> __y) noexcept
489 { return !(__x == __y); }
490
491 template<typename _CharT, typename _Traits>
492 constexpr bool
493 operator< (basic_string_view<_CharT, _Traits> __x,
494 basic_string_view<_CharT, _Traits> __y) noexcept
495 { return __x.compare(__y) < 0; }
496
497 template<typename _CharT, typename _Traits>
498 constexpr bool
499 operator< (basic_string_view<_CharT, _Traits> __x,
500 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
501 { return __x.compare(__y) < 0; }
502
503 template<typename _CharT, typename _Traits>
504 constexpr bool
505 operator< (__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
506 basic_string_view<_CharT, _Traits> __y) noexcept
507 { return __x.compare(__y) < 0; }
508
509 template<typename _CharT, typename _Traits>
510 constexpr bool
511 operator> (basic_string_view<_CharT, _Traits> __x,
512 basic_string_view<_CharT, _Traits> __y) noexcept
513 { return __x.compare(__y) > 0; }
514
515 template<typename _CharT, typename _Traits>
516 constexpr bool
517 operator> (basic_string_view<_CharT, _Traits> __x,
518 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
519 { return __x.compare(__y) > 0; }
520
521 template<typename _CharT, typename _Traits>
522 constexpr bool
523 operator> (__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
524 basic_string_view<_CharT, _Traits> __y) noexcept
525 { return __x.compare(__y) > 0; }
526
527 template<typename _CharT, typename _Traits>
528 constexpr bool
529 operator<=(basic_string_view<_CharT, _Traits> __x,
530 basic_string_view<_CharT, _Traits> __y) noexcept
531 { return __x.compare(__y) <= 0; }
532
533 template<typename _CharT, typename _Traits>
534 constexpr bool
535 operator<=(basic_string_view<_CharT, _Traits> __x,
536 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
537 { return __x.compare(__y) <= 0; }
538
539 template<typename _CharT, typename _Traits>
540 constexpr bool
541 operator<=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
542 basic_string_view<_CharT, _Traits> __y) noexcept
543 { return __x.compare(__y) <= 0; }
544
545 template<typename _CharT, typename _Traits>
546 constexpr bool
547 operator>=(basic_string_view<_CharT, _Traits> __x,
548 basic_string_view<_CharT, _Traits> __y) noexcept
549 { return __x.compare(__y) >= 0; }
550
551 template<typename _CharT, typename _Traits>
552 constexpr bool
553 operator>=(basic_string_view<_CharT, _Traits> __x,
554 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
555 { return __x.compare(__y) >= 0; }
556
557 template<typename _CharT, typename _Traits>
558 constexpr bool
559 operator>=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
560 basic_string_view<_CharT, _Traits> __y) noexcept
561 { return __x.compare(__y) >= 0; }
562
563 // [string.view.io], Inserters and extractors
564 template<typename _CharT, typename _Traits>
565 inline basic_ostream<_CharT, _Traits>&
566 operator<<(basic_ostream<_CharT, _Traits>& __os,
567 basic_string_view<_CharT,_Traits> __str)
568 { return __ostream_insert(__os, __str.data(), __str.size()); }
569
570
571 // basic_string_view typedef names
572
573 using string_view = basic_string_view<char>;
574#ifdef _GLIBCXX_USE_WCHAR_T
575 using wstring_view = basic_string_view<wchar_t>;
576#endif
577#ifdef _GLIBCXX_USE_C99_STDINT_TR1
578 using u16string_view = basic_string_view<char16_t>;
579 using u32string_view = basic_string_view<char32_t>;
580#endif
581
582_GLIBCXX_END_NAMESPACE_VERSION
583} // namespace fundamentals_v1
584} // namespace experimental
585
586
587 // [string.view.hash], hash support:
588
589_GLIBCXX_BEGIN_NAMESPACE_VERSION
590 template<typename _Tp>
591 struct hash;
592
593 template<>
594 struct hash<experimental::string_view>
595 : public __hash_base<size_t, experimental::string_view>
596 {
597 size_t
598 operator()(const experimental::string_view& __str) const noexcept
599 { return std::_Hash_impl::hash(__str.data(), __str.length()); }
600 };
601
602 template<>
603 struct __is_fast_hash<hash<experimental::string_view>> : std::false_type
604 { };
605
606#ifdef _GLIBCXX_USE_WCHAR_T
607 template<>
608 struct hash<experimental::wstring_view>
609 : public __hash_base<size_t, wstring>
610 {
611 size_t
612 operator()(const experimental::wstring_view& __s) const noexcept
613 { return std::_Hash_impl::hash(__s.data(),
614 __s.length() * sizeof(wchar_t)); }
615 };
616
617 template<>
618 struct __is_fast_hash<hash<experimental::wstring_view>> : std::false_type
619 { };
620#endif
621
622#ifdef _GLIBCXX_USE_C99_STDINT_TR1
623 template<>
624 struct hash<experimental::u16string_view>
625 : public __hash_base<size_t, experimental::u16string_view>
626 {
627 size_t
628 operator()(const experimental::u16string_view& __s) const noexcept
629 { return std::_Hash_impl::hash(__s.data(),
630 __s.length() * sizeof(char16_t)); }
631 };
632
633 template<>
634 struct __is_fast_hash<hash<experimental::u16string_view>> : std::false_type
635 { };
636
637 template<>
638 struct hash<experimental::u32string_view>
639 : public __hash_base<size_t, experimental::u32string_view>
640 {
641 size_t
642 operator()(const experimental::u32string_view& __s) const noexcept
643 { return std::_Hash_impl::hash(__s.data(),
644 __s.length() * sizeof(char32_t)); }
645 };
646
647 template<>
648 struct __is_fast_hash<hash<experimental::u32string_view>> : std::false_type
649 { };
650#endif
651_GLIBCXX_END_NAMESPACE_VERSION
652
653namespace experimental
654{
655 // I added these EMSR.
656 inline namespace literals
657 {
658 inline namespace string_view_literals
659 {
660 _GLIBCXX_BEGIN_NAMESPACE_VERSION
661
662 inline constexpr basic_string_view<char>
663 operator""sv(const char* __str, size_t __len) noexcept
664 { return basic_string_view<char>{__str, __len}; }
665
666#ifdef _GLIBCXX_USE_WCHAR_T
667 inline constexpr basic_string_view<wchar_t>
668 operator""sv(const wchar_t* __str, size_t __len) noexcept
669 { return basic_string_view<wchar_t>{__str, __len}; }
670#endif
671
672#ifdef _GLIBCXX_USE_C99_STDINT_TR1
673 inline constexpr basic_string_view<char16_t>
674 operator""sv(const char16_t* __str, size_t __len) noexcept
675 { return basic_string_view<char16_t>{__str, __len}; }
676
677 inline constexpr basic_string_view<char32_t>
678 operator""sv(const char32_t* __str, size_t __len) noexcept
679 { return basic_string_view<char32_t>{__str, __len}; }
680#endif
681
682 _GLIBCXX_END_NAMESPACE_VERSION
683 } // namespace string_literals
684 } // namespace literals
685} // namespace experimental
686} // namespace std
687
688#include <experimental/bits/string_view.tcc>
689
690#endif // __cplusplus <= 201103L
691
692#endif // _GLIBCXX_EXPERIMENTAL_STRING_VIEW