1 // Components for manipulating non-owning sequences of characters -*- C++ -*-
3 // Copyright (C) 2013-2018 Free Software Foundation, Inc.
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)
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.
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.
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/>.
26 * This is a Standard C++ Library header.
30 // N3762 basic_string_view library
33 #ifndef _GLIBCXX_STRING_VIEW
34 #define _GLIBCXX_STRING_VIEW 1
36 #pragma GCC system_header
38 #if __cplusplus >= 201703L
42 #include <bits/char_traits.h>
43 #include <bits/functional_hash.h>
44 #include <bits/range_access.h>
46 namespace std _GLIBCXX_VISIBILITY(default)
48 _GLIBCXX_BEGIN_NAMESPACE_VERSION
50 #define __cpp_lib_string_view 201603
53 * @class basic_string_view <string_view>
54 * @brief A non-owning reference to a string.
59 * @tparam _CharT Type of character
60 * @tparam _Traits Traits for character type, defaults to
61 * char_traits<_CharT>.
63 * A basic_string_view looks like this:
70 template<typename _CharT, typename _Traits = std::char_traits<_CharT>>
71 class basic_string_view
76 using traits_type = _Traits;
77 using value_type = _CharT;
78 using pointer = const _CharT*;
79 using const_pointer = const _CharT*;
80 using reference = const _CharT&;
81 using const_reference = const _CharT&;
82 using const_iterator = const _CharT*;
83 using iterator = const_iterator;
84 using const_reverse_iterator = std::reverse_iterator<const_iterator>;
85 using reverse_iterator = const_reverse_iterator;
86 using size_type = size_t;
87 using difference_type = ptrdiff_t;
88 static constexpr size_type npos = size_type(-1);
90 // [string.view.cons], construct/copy
93 basic_string_view() noexcept
94 : _M_len{0}, _M_str{nullptr}
97 constexpr basic_string_view(const basic_string_view&) noexcept = default;
99 __attribute__((__nonnull__)) constexpr
100 basic_string_view(const _CharT* __str) noexcept
101 : _M_len{traits_type::length(__str)},
106 basic_string_view(const _CharT* __str, size_type __len) noexcept
107 : _M_len{__len}, _M_str{__str}
110 constexpr basic_string_view&
111 operator=(const basic_string_view&) noexcept = default;
113 // [string.view.iterators], iterators
115 constexpr const_iterator
116 begin() const noexcept
117 { return this->_M_str; }
119 constexpr const_iterator
121 { return this->_M_str + this->_M_len; }
123 constexpr const_iterator
124 cbegin() const noexcept
125 { return this->_M_str; }
127 constexpr const_iterator
128 cend() const noexcept
129 { return this->_M_str + this->_M_len; }
131 constexpr const_reverse_iterator
132 rbegin() const noexcept
133 { return const_reverse_iterator(this->end()); }
135 constexpr const_reverse_iterator
136 rend() const noexcept
137 { return const_reverse_iterator(this->begin()); }
139 constexpr const_reverse_iterator
140 crbegin() const noexcept
141 { return const_reverse_iterator(this->end()); }
143 constexpr const_reverse_iterator
144 crend() const noexcept
145 { return const_reverse_iterator(this->begin()); }
147 // [string.view.capacity], capacity
150 size() const noexcept
151 { return this->_M_len; }
154 length() const noexcept
158 max_size() const noexcept
160 return (npos - sizeof(size_type) - sizeof(void*))
161 / sizeof(value_type) / 4;
164 [[nodiscard]] constexpr bool
165 empty() const noexcept
166 { return this->_M_len == 0; }
168 // [string.view.access], element access
170 constexpr const _CharT&
171 operator[](size_type __pos) const noexcept
173 // TODO: Assert to restore in a way compatible with the constexpr.
174 // __glibcxx_assert(__pos < this->_M_len);
175 return *(this->_M_str + __pos);
178 constexpr const _CharT&
179 at(size_type __pos) const
182 __throw_out_of_range_fmt(__N("basic_string_view::at: __pos "
183 "(which is %zu) >= this->size() "
184 "(which is %zu)"), __pos, this->size());
185 return *(this->_M_str + __pos);
188 constexpr const _CharT&
189 front() const noexcept
191 // TODO: Assert to restore in a way compatible with the constexpr.
192 // __glibcxx_assert(this->_M_len > 0);
193 return *this->_M_str;
196 constexpr const _CharT&
197 back() const noexcept
199 // TODO: Assert to restore in a way compatible with the constexpr.
200 // __glibcxx_assert(this->_M_len > 0);
201 return *(this->_M_str + this->_M_len - 1);
204 constexpr const _CharT*
205 data() const noexcept
206 { return this->_M_str; }
208 // [string.view.modifiers], modifiers:
211 remove_prefix(size_type __n) noexcept
213 __glibcxx_assert(this->_M_len >= __n);
219 remove_suffix(size_type __n) noexcept
220 { this->_M_len -= __n; }
223 swap(basic_string_view& __sv) noexcept
231 // [string.view.ops], string operations:
234 copy(_CharT* __str, size_type __n, size_type __pos = 0) const
236 __glibcxx_requires_string_len(__str, __n);
237 __pos = _M_check(__pos, "basic_string_view::copy");
238 const size_type __rlen = std::min(__n, _M_len - __pos);
239 for (auto __begin = this->_M_str + __pos,
240 __end = __begin + __rlen; __begin != __end;)
241 *__str++ = *__begin++;
245 constexpr basic_string_view
246 substr(size_type __pos, size_type __n = npos) const noexcept(false)
248 __pos = _M_check(__pos, "basic_string_view::substr");
249 const size_type __rlen = std::min(__n, _M_len - __pos);
250 return basic_string_view{_M_str + __pos, __rlen};
254 compare(basic_string_view __str) const noexcept
256 const size_type __rlen = std::min(this->_M_len, __str._M_len);
257 int __ret = traits_type::compare(this->_M_str, __str._M_str, __rlen);
259 __ret = _S_compare(this->_M_len, __str._M_len);
264 compare(size_type __pos1, size_type __n1, basic_string_view __str) const
265 { return this->substr(__pos1, __n1).compare(__str); }
268 compare(size_type __pos1, size_type __n1,
269 basic_string_view __str, size_type __pos2, size_type __n2) const
271 return this->substr(__pos1, __n1).compare(__str.substr(__pos2, __n2));
274 __attribute__((__nonnull__)) constexpr int
275 compare(const _CharT* __str) const noexcept
276 { return this->compare(basic_string_view{__str}); }
278 __attribute__((__nonnull__)) constexpr int
279 compare(size_type __pos1, size_type __n1, const _CharT* __str) const
280 { return this->substr(__pos1, __n1).compare(basic_string_view{__str}); }
283 compare(size_type __pos1, size_type __n1,
284 const _CharT* __str, size_type __n2) const noexcept(false)
286 return this->substr(__pos1, __n1)
287 .compare(basic_string_view(__str, __n2));
291 find(basic_string_view __str, size_type __pos = 0) const noexcept
292 { return this->find(__str._M_str, __pos, __str._M_len); }
295 find(_CharT __c, size_type __pos = 0) const noexcept;
298 find(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
300 __attribute__((__nonnull__)) constexpr size_type
301 find(const _CharT* __str, size_type __pos = 0) const noexcept
302 { return this->find(__str, __pos, traits_type::length(__str)); }
305 rfind(basic_string_view __str, size_type __pos = npos) const noexcept
306 { return this->rfind(__str._M_str, __pos, __str._M_len); }
309 rfind(_CharT __c, size_type __pos = npos) const noexcept;
312 rfind(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
314 __attribute__((__nonnull__)) constexpr size_type
315 rfind(const _CharT* __str, size_type __pos = npos) const noexcept
316 { return this->rfind(__str, __pos, traits_type::length(__str)); }
319 find_first_of(basic_string_view __str, size_type __pos = 0) const noexcept
320 { return this->find_first_of(__str._M_str, __pos, __str._M_len); }
323 find_first_of(_CharT __c, size_type __pos = 0) const noexcept
324 { return this->find(__c, __pos); }
327 find_first_of(const _CharT* __str, size_type __pos,
328 size_type __n) const noexcept;
330 __attribute__((__nonnull__)) constexpr size_type
331 find_first_of(const _CharT* __str, size_type __pos = 0) const noexcept
332 { return this->find_first_of(__str, __pos, traits_type::length(__str)); }
335 find_last_of(basic_string_view __str,
336 size_type __pos = npos) const noexcept
337 { return this->find_last_of(__str._M_str, __pos, __str._M_len); }
340 find_last_of(_CharT __c, size_type __pos=npos) const noexcept
341 { return this->rfind(__c, __pos); }
344 find_last_of(const _CharT* __str, size_type __pos,
345 size_type __n) const noexcept;
347 __attribute__((__nonnull__)) constexpr size_type
348 find_last_of(const _CharT* __str, size_type __pos = npos) const noexcept
349 { return this->find_last_of(__str, __pos, traits_type::length(__str)); }
352 find_first_not_of(basic_string_view __str,
353 size_type __pos = 0) const noexcept
354 { return this->find_first_not_of(__str._M_str, __pos, __str._M_len); }
357 find_first_not_of(_CharT __c, size_type __pos = 0) const noexcept;
360 find_first_not_of(const _CharT* __str,
361 size_type __pos, size_type __n) const noexcept;
363 __attribute__((__nonnull__)) constexpr size_type
364 find_first_not_of(const _CharT* __str, size_type __pos = 0) const noexcept
366 return this->find_first_not_of(__str, __pos,
367 traits_type::length(__str));
371 find_last_not_of(basic_string_view __str,
372 size_type __pos = npos) const noexcept
373 { return this->find_last_not_of(__str._M_str, __pos, __str._M_len); }
376 find_last_not_of(_CharT __c, size_type __pos = npos) const noexcept;
379 find_last_not_of(const _CharT* __str,
380 size_type __pos, size_type __n) const noexcept;
382 __attribute__((__nonnull__)) constexpr size_type
383 find_last_not_of(const _CharT* __str,
384 size_type __pos = npos) const noexcept
386 return this->find_last_not_of(__str, __pos,
387 traits_type::length(__str));
391 _M_check(size_type __pos, const char* __s) const noexcept(false)
393 if (__pos > this->size())
394 __throw_out_of_range_fmt(__N("%s: __pos (which is %zu) > "
395 "this->size() (which is %zu)"),
396 __s, __pos, this->size());
400 // NB: _M_limit doesn't check for a bad __pos value.
402 _M_limit(size_type __pos, size_type __off) const noexcept
404 const bool __testoff = __off < this->size() - __pos;
405 return __testoff ? __off : this->size() - __pos;
411 _S_compare(size_type __n1, size_type __n2) noexcept
413 const difference_type __diff = __n1 - __n2;
414 if (__diff > std::numeric_limits<int>::max())
415 return std::numeric_limits<int>::max();
416 if (__diff < std::numeric_limits<int>::min())
417 return std::numeric_limits<int>::min();
418 return static_cast<int>(__diff);
422 const _CharT* _M_str;
425 // [string.view.comparison], non-member basic_string_view comparison function
429 // Identity transform to create a non-deduced context, so that only one
430 // argument participates in template argument deduction and the other
431 // argument gets implicitly converted to the deduced type. See n3766.html.
432 template<typename _Tp>
433 using __idt = common_type_t<_Tp>;
436 template<typename _CharT, typename _Traits>
438 operator==(basic_string_view<_CharT, _Traits> __x,
439 basic_string_view<_CharT, _Traits> __y) noexcept
440 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
442 template<typename _CharT, typename _Traits>
444 operator==(basic_string_view<_CharT, _Traits> __x,
445 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
446 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
448 template<typename _CharT, typename _Traits>
450 operator==(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
451 basic_string_view<_CharT, _Traits> __y) noexcept
452 { return __x.size() == __y.size() && __x.compare(__y) == 0; }
454 template<typename _CharT, typename _Traits>
456 operator!=(basic_string_view<_CharT, _Traits> __x,
457 basic_string_view<_CharT, _Traits> __y) noexcept
458 { return !(__x == __y); }
460 template<typename _CharT, typename _Traits>
462 operator!=(basic_string_view<_CharT, _Traits> __x,
463 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
464 { return !(__x == __y); }
466 template<typename _CharT, typename _Traits>
468 operator!=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
469 basic_string_view<_CharT, _Traits> __y) noexcept
470 { return !(__x == __y); }
472 template<typename _CharT, typename _Traits>
474 operator< (basic_string_view<_CharT, _Traits> __x,
475 basic_string_view<_CharT, _Traits> __y) noexcept
476 { return __x.compare(__y) < 0; }
478 template<typename _CharT, typename _Traits>
480 operator< (basic_string_view<_CharT, _Traits> __x,
481 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
482 { return __x.compare(__y) < 0; }
484 template<typename _CharT, typename _Traits>
486 operator< (__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
487 basic_string_view<_CharT, _Traits> __y) noexcept
488 { return __x.compare(__y) < 0; }
490 template<typename _CharT, typename _Traits>
492 operator> (basic_string_view<_CharT, _Traits> __x,
493 basic_string_view<_CharT, _Traits> __y) noexcept
494 { return __x.compare(__y) > 0; }
496 template<typename _CharT, typename _Traits>
498 operator> (basic_string_view<_CharT, _Traits> __x,
499 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
500 { return __x.compare(__y) > 0; }
502 template<typename _CharT, typename _Traits>
504 operator> (__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
505 basic_string_view<_CharT, _Traits> __y) noexcept
506 { return __x.compare(__y) > 0; }
508 template<typename _CharT, typename _Traits>
510 operator<=(basic_string_view<_CharT, _Traits> __x,
511 basic_string_view<_CharT, _Traits> __y) noexcept
512 { return __x.compare(__y) <= 0; }
514 template<typename _CharT, typename _Traits>
516 operator<=(basic_string_view<_CharT, _Traits> __x,
517 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
518 { return __x.compare(__y) <= 0; }
520 template<typename _CharT, typename _Traits>
522 operator<=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
523 basic_string_view<_CharT, _Traits> __y) noexcept
524 { return __x.compare(__y) <= 0; }
526 template<typename _CharT, typename _Traits>
528 operator>=(basic_string_view<_CharT, _Traits> __x,
529 basic_string_view<_CharT, _Traits> __y) noexcept
530 { return __x.compare(__y) >= 0; }
532 template<typename _CharT, typename _Traits>
534 operator>=(basic_string_view<_CharT, _Traits> __x,
535 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
536 { return __x.compare(__y) >= 0; }
538 template<typename _CharT, typename _Traits>
540 operator>=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
541 basic_string_view<_CharT, _Traits> __y) noexcept
542 { return __x.compare(__y) >= 0; }
544 // [string.view.io], Inserters and extractors
545 template<typename _CharT, typename _Traits>
546 inline basic_ostream<_CharT, _Traits>&
547 operator<<(basic_ostream<_CharT, _Traits>& __os,
548 basic_string_view<_CharT,_Traits> __str)
549 { return __ostream_insert(__os, __str.data(), __str.size()); }
552 // basic_string_view typedef names
554 using string_view = basic_string_view<char>;
555 #ifdef _GLIBCXX_USE_WCHAR_T
556 using wstring_view = basic_string_view<wchar_t>;
559 using u16string_view = basic_string_view<char16_t>;
560 using u32string_view = basic_string_view<char32_t>;
562 // [string.view.hash], hash support:
564 template<typename _Tp>
568 struct hash<string_view>
569 : public __hash_base<size_t, string_view>
572 operator()(const string_view& __str) const noexcept
573 { return std::_Hash_impl::hash(__str.data(), __str.length()); }
577 struct __is_fast_hash<hash<string_view>> : std::false_type
580 #ifdef _GLIBCXX_USE_WCHAR_T
582 struct hash<wstring_view>
583 : public __hash_base<size_t, wstring>
586 operator()(const wstring_view& __s) const noexcept
587 { return std::_Hash_impl::hash(__s.data(),
588 __s.length() * sizeof(wchar_t)); }
592 struct __is_fast_hash<hash<wstring_view>> : std::false_type
597 struct hash<u16string_view>
598 : public __hash_base<size_t, u16string_view>
601 operator()(const u16string_view& __s) const noexcept
602 { return std::_Hash_impl::hash(__s.data(),
603 __s.length() * sizeof(char16_t)); }
607 struct __is_fast_hash<hash<u16string_view>> : std::false_type
611 struct hash<u32string_view>
612 : public __hash_base<size_t, u32string_view>
615 operator()(const u32string_view& __s) const noexcept
616 { return std::_Hash_impl::hash(__s.data(),
617 __s.length() * sizeof(char32_t)); }
621 struct __is_fast_hash<hash<u32string_view>> : std::false_type
624 inline namespace literals
626 inline namespace string_view_literals
628 #pragma GCC diagnostic push
629 #pragma GCC diagnostic ignored "-Wliteral-suffix"
630 inline constexpr basic_string_view<char>
631 operator""sv(const char* __str, size_t __len) noexcept
632 { return basic_string_view<char>{__str, __len}; }
634 #ifdef _GLIBCXX_USE_WCHAR_T
635 inline constexpr basic_string_view<wchar_t>
636 operator""sv(const wchar_t* __str, size_t __len) noexcept
637 { return basic_string_view<wchar_t>{__str, __len}; }
640 inline constexpr basic_string_view<char16_t>
641 operator""sv(const char16_t* __str, size_t __len) noexcept
642 { return basic_string_view<char16_t>{__str, __len}; }
644 inline constexpr basic_string_view<char32_t>
645 operator""sv(const char32_t* __str, size_t __len) noexcept
646 { return basic_string_view<char32_t>{__str, __len}; }
648 #pragma GCC diagnostic pop
649 } // namespace string_literals
650 } // namespace literals
652 _GLIBCXX_END_NAMESPACE_VERSION
655 #include <bits/string_view.tcc>
657 #endif // __cplusplus <= 201402L
659 #endif // _GLIBCXX_EXPERIMENTAL_STRING_VIEW