1 // Components for manipulating non-owning sequences of characters -*- C++ -*-
3 // Copyright (C) 2013-2014 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/>.
25 /** @file experimental/string_view
26 * This is a Standard C++ Library header.
30 // N3762 basic_string_view library
33 #ifndef _GLIBCXX_EXPERIMENTAL_STRING_VIEW
34 #define _GLIBCXX_EXPERIMENTAL_STRING_VIEW 1
36 #pragma GCC system_header
38 #if __cplusplus <= 201103L
39 # include <bits/c++14_warning.h>
42 #include <debug/debug.h>
46 namespace std _GLIBCXX_VISIBILITY(default)
48 namespace experimental
50 _GLIBCXX_BEGIN_NAMESPACE_VERSION
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 * A basic_string_view represents an empty string with a static constexpr
74 * static constexpr value_type _S_empty_str[1]{0};
77 template<typename _CharT, typename _Traits = char_traits<_CharT>>
78 class basic_string_view
84 using traits_type = _Traits;
85 using value_type = _CharT;
86 using pointer = const _CharT*;
87 using const_pointer = const _CharT*;
88 using reference = const _CharT&;
89 using const_reference = const _CharT&;
90 using const_iterator = const _CharT*;
91 using iterator = const_iterator;
92 using const_reverse_iterator = std::reverse_iterator<const_iterator>;
93 using reverse_iterator = const_reverse_iterator;
94 using size_type = size_t;
95 using difference_type = ptrdiff_t;
96 static constexpr size_type npos = size_type(-1);
98 // [string.view.cons], construct/copy
101 basic_string_view() noexcept
102 : _M_len{0}, _M_str{_S_empty_str}
105 constexpr basic_string_view(const basic_string_view&) noexcept = default;
107 template<typename _Allocator>
108 basic_string_view(const basic_string<_CharT, _Traits,
109 _Allocator>& __str) noexcept
110 : _M_len{__str.length()}, _M_str{__str.data()}
113 constexpr basic_string_view(const _CharT* __str)
114 : _M_len{__str == nullptr ? 0 : traits_type::length(__str)},
115 _M_str{__str == nullptr ? _S_empty_str : __str}
118 constexpr basic_string_view(const _CharT* __str, size_type __len)
119 : _M_len{__str == nullptr ? 0 :__len},
120 _M_str{__str == nullptr ? _S_empty_str : __str}
124 operator=(const basic_string_view&) noexcept = default;
126 // [string.view.iterators], iterators
128 constexpr const_iterator
129 begin() const noexcept
130 { return this->_M_str; }
132 constexpr const_iterator
134 { return this->_M_str + this->_M_len; }
136 constexpr const_iterator
137 cbegin() const noexcept
138 { return this->_M_str; }
140 constexpr const_iterator
141 cend() const noexcept
142 { return this->_M_str + this->_M_len; }
144 const_reverse_iterator
145 rbegin() const noexcept
146 { return std::reverse_iterator<const_iterator>(this->end()); }
148 const_reverse_iterator
149 rend() const noexcept
150 { return std::reverse_iterator<const_iterator>(this->begin()); }
152 const_reverse_iterator
153 crbegin() const noexcept
154 { return std::reverse_iterator<const_iterator>(this->end()); }
156 const_reverse_iterator
157 crend() const noexcept
158 { return std::reverse_iterator<const_iterator>(this->begin()); }
160 // [string.view.capacity], capacity
163 size() const noexcept
164 { return this->_M_len; }
167 length() const noexcept
171 max_size() const noexcept
172 { return ((npos - sizeof(size_type) - sizeof(void*))
173 / sizeof(value_type) / 4); }
176 empty() const noexcept
177 { return this->_M_len == 0; }
179 // [string.view.access], element access
181 constexpr const _CharT&
182 operator[](size_type __pos) const
184 // TODO: Assert to restore in a way compatible with the constexpr.
185 // _GLIBCXX_DEBUG_ASSERT(__pos < this->_M_len);
186 return *(this->_M_str + __pos);
189 constexpr const _CharT&
190 at(size_type __pos) const
192 return __pos < this->_M_len
193 ? *(this->_M_str + __pos)
194 : (__throw_out_of_range_fmt(__N("basic_string_view::at: __pos "
195 "(which is %zu) >= this->size() "
197 __pos, this->size()),
201 constexpr const _CharT&
204 // TODO: Assert to restore in a way compatible with the constexpr.
205 // _GLIBCXX_DEBUG_ASSERT(this->_M_len > 0);
206 return *this->_M_str;
209 constexpr const _CharT&
212 // TODO: Assert to restore in a way compatible with the constexpr.
213 // _GLIBCXX_DEBUG_ASSERT(this->_M_len > 0);
214 return *(this->_M_str + this->_M_len - 1);
217 constexpr const _CharT*
218 data() const noexcept
219 { return this->_M_str; }
221 // [string.view.modifiers], modifiers:
226 this->_M_str = _S_empty_str;
230 remove_prefix(size_type __n)
232 _GLIBCXX_DEBUG_ASSERT(this->_M_len >= __n);
238 remove_suffix(size_type __n)
239 { this->_M_len -= __n; }
242 swap(basic_string_view& __sv) noexcept
244 std::swap(this->_M_len, __sv._M_len);
245 std::swap(this->_M_str, __sv._M_str);
249 // [string.view.ops], string operations:
251 template<typename _Allocator>
252 explicit operator basic_string<_CharT, _Traits, _Allocator>() const
254 return basic_string<_CharT, _Traits, _Allocator>
255 (this->_M_len, this->_M_str);
259 copy(_CharT* __str, size_type __n, size_type __pos = 0) const
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() "
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++;
275 // [string.view.ops], string operations:
277 constexpr basic_string_view
278 substr(size_type __pos, size_type __n=npos) const
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() "
286 __pos, this->size()), basic_string_view{});
290 compare(basic_string_view __str) const noexcept
292 int __ret = traits_type::compare(this->_M_str, __str._M_str,
293 std::min(this->_M_len, __str._M_len));
295 __ret = _S_compare(this->_M_len, __str._M_len);
300 compare(size_type __pos1, size_type __n1, basic_string_view __str) const
301 { return this->substr(__pos1, __n1).compare(__str); }
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)); }
309 compare(const _CharT* __str) const noexcept
310 { return this->compare(basic_string_view{__str}); }
313 compare(size_type __pos1, size_type __n1, const _CharT* __str) const
314 { return this->substr(__pos1, __n1).compare(basic_string_view{__str}); }
317 compare(size_type __pos1, size_type __n1,
318 const _CharT* __str, size_type __n2) const
320 return this->substr(__pos1, __n1)
321 .compare(basic_string_view(__str, __n2));
325 find(basic_string_view __str, size_type __pos = 0) const noexcept
326 { return this->find(__str._M_str, __pos, __str._M_len); }
329 find(_CharT __c, size_type __pos=0) const noexcept;
332 find(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
335 find(const _CharT* __str, size_type __pos=0) const noexcept
336 { return this->find(__str, __pos, traits_type::length(__str)); }
339 rfind(basic_string_view __str, size_type __pos = npos) const noexcept
340 { return this->rfind(__str._M_str, __pos, __str._M_len); }
343 rfind(_CharT __c, size_type __pos = npos) const noexcept;
346 rfind(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
349 rfind(const _CharT* __str, size_type __pos = npos) const noexcept
350 { return this->rfind(__str, __pos, traits_type::length(__str)); }
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); }
357 find_first_of(_CharT __c, size_type __pos = 0) const noexcept
358 { return this->find(__c, __pos); }
361 find_first_of(const _CharT* __str, size_type __pos, size_type __n) const;
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)); }
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); }
373 find_last_of(_CharT __c, size_type __pos=npos) const noexcept
374 { return this->rfind(__c, __pos); }
377 find_last_of(const _CharT* __str, size_type __pos, size_type __n) const;
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)); }
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); }
389 find_first_not_of(_CharT __c, size_type __pos = 0) const noexcept;
392 find_first_not_of(const _CharT* __str,
393 size_type __pos, size_type __n) const;
396 find_first_not_of(const _CharT* __str, size_type __pos = 0) const noexcept
398 return this->find_first_not_of(__str, __pos,
399 traits_type::length(__str));
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); }
408 find_last_not_of(_CharT __c, size_type __pos = npos) const noexcept;
411 find_last_not_of(const _CharT* __str,
412 size_type __pos, size_type __n) const;
415 find_last_not_of(const _CharT* __str,
416 size_type __pos = npos) const noexcept
418 return this->find_last_not_of(__str, __pos,
419 traits_type::length(__str));
424 static constexpr const int
425 _S_compare(size_type __n1, size_type __n2) noexcept
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});
434 static constexpr value_type _S_empty_str[1]{};
437 const _CharT* _M_str;
441 // [string.view.comparison], non-member basic_string_view comparison functions
445 // Identity transform to make ADL work with just one argument.
447 template<typename _Tp = void>
449 { typedef _Tp type; };
452 struct __identity<void>;
454 template<typename _Tp>
455 using __idt = typename __identity<_Tp>::type;
458 template<typename _CharT, typename _Traits>
460 operator==(basic_string_view<_CharT, _Traits> __x,
461 basic_string_view<_CharT, _Traits> __y) noexcept
462 { return __x.compare(__y) == 0; }
464 template<typename _CharT, typename _Traits>
466 operator==(basic_string_view<_CharT, _Traits> __x,
467 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
468 { return __x.compare(__y) == 0; }
470 template<typename _CharT, typename _Traits>
472 operator==(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
473 basic_string_view<_CharT, _Traits> __y) noexcept
474 { return __x.compare(__y) == 0; }
476 template<typename _CharT, typename _Traits>
478 operator!=(basic_string_view<_CharT, _Traits> __x,
479 basic_string_view<_CharT, _Traits> __y) noexcept
480 { return !(__x == __y); }
482 template<typename _CharT, typename _Traits>
484 operator!=(basic_string_view<_CharT, _Traits> __x,
485 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
486 { return !(__x == __y); }
488 template<typename _CharT, typename _Traits>
490 operator!=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
491 basic_string_view<_CharT, _Traits> __y) noexcept
492 { return !(__x == __y); }
494 template<typename _CharT, typename _Traits>
496 operator< (basic_string_view<_CharT, _Traits> __x,
497 basic_string_view<_CharT, _Traits> __y) noexcept
498 { return __x.compare(__y) < 0; }
500 template<typename _CharT, typename _Traits>
502 operator< (basic_string_view<_CharT, _Traits> __x,
503 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
504 { return __x.compare(__y) < 0; }
506 template<typename _CharT, typename _Traits>
508 operator< (__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
509 basic_string_view<_CharT, _Traits> __y) noexcept
510 { return __x.compare(__y) < 0; }
512 template<typename _CharT, typename _Traits>
514 operator> (basic_string_view<_CharT, _Traits> __x,
515 basic_string_view<_CharT, _Traits> __y) noexcept
516 { return __x.compare(__y) > 0; }
518 template<typename _CharT, typename _Traits>
520 operator> (basic_string_view<_CharT, _Traits> __x,
521 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
522 { return __x.compare(__y) > 0; }
524 template<typename _CharT, typename _Traits>
526 operator> (__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
527 basic_string_view<_CharT, _Traits> __y) noexcept
528 { return __x.compare(__y) > 0; }
530 template<typename _CharT, typename _Traits>
532 operator<=(basic_string_view<_CharT, _Traits> __x,
533 basic_string_view<_CharT, _Traits> __y) noexcept
534 { return __x.compare(__y) <= 0; }
536 template<typename _CharT, typename _Traits>
538 operator<=(basic_string_view<_CharT, _Traits> __x,
539 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
540 { return __x.compare(__y) <= 0; }
542 template<typename _CharT, typename _Traits>
544 operator<=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
545 basic_string_view<_CharT, _Traits> __y) noexcept
546 { return __x.compare(__y) <= 0; }
548 template<typename _CharT, typename _Traits>
550 operator>=(basic_string_view<_CharT, _Traits> __x,
551 basic_string_view<_CharT, _Traits> __y) noexcept
552 { return __x.compare(__y) >= 0; }
554 template<typename _CharT, typename _Traits>
556 operator>=(basic_string_view<_CharT, _Traits> __x,
557 __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
558 { return __x.compare(__y) >= 0; }
560 template<typename _CharT, typename _Traits>
562 operator>=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
563 basic_string_view<_CharT, _Traits> __y) noexcept
564 { return __x.compare(__y) >= 0; }
566 // [string.view.comparison], sufficient additional overloads of comparison functions
568 // [string.view.nonmem], other non-member basic_string_view functions
569 template<typename _CharT, typename _Traits = char_traits<_CharT>,
570 typename _Allocator = allocator<_CharT>>
571 basic_string<_CharT, _Traits, _Allocator>
572 to_string(basic_string_view<_CharT, _Traits> __str,
573 const _Allocator& __alloc = _Allocator())
575 return basic_string<_CharT, _Traits, _Allocator>
576 (__str.begin(), __str.end(), __alloc);
579 template<typename _CharT, typename _Traits>
580 basic_ostream<_CharT, _Traits>&
581 operator<<(basic_ostream<_CharT, _Traits>& __os,
582 basic_string_view<_CharT,_Traits> __str)
583 { return __ostream_insert(__os, __str.data(), __str.size()); }
586 // basic_string_view typedef names
588 using string_view = basic_string_view<char>;
589 #ifdef _GLIBCXX_USE_WCHAR_T
590 using wstring_view = basic_string_view<wchar_t>;
592 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
593 using u16string_view = basic_string_view<char16_t>;
594 using u32string_view = basic_string_view<char32_t>;
597 _GLIBCXX_END_NAMESPACE_VERSION
598 } // namespace experimental
601 // [string.view.hash], hash support:
603 _GLIBCXX_BEGIN_NAMESPACE_VERSION
604 template<typename _Tp>
608 struct hash<experimental::string_view>
609 : public __hash_base<size_t, experimental::string_view>
612 operator()(const experimental::string_view& __str) const noexcept
613 { return std::_Hash_impl::hash(__str.data(), __str.length()); }
617 struct __is_fast_hash<hash<experimental::string_view>> : std::false_type
620 #ifdef _GLIBCXX_USE_WCHAR_T
622 struct hash<experimental::wstring_view>
623 : public __hash_base<size_t, wstring>
626 operator()(const experimental::wstring_view& __s) const noexcept
627 { return std::_Hash_impl::hash(__s.data(),
628 __s.length() * sizeof(wchar_t)); }
632 struct __is_fast_hash<hash<experimental::wstring_view>> : std::false_type
636 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
638 struct hash<experimental::u16string_view>
639 : public __hash_base<size_t, experimental::u16string_view>
642 operator()(const experimental::u16string_view& __s) const noexcept
643 { return std::_Hash_impl::hash(__s.data(),
644 __s.length() * sizeof(char16_t)); }
648 struct __is_fast_hash<hash<experimental::u16string_view>> : std::false_type
652 struct hash<experimental::u32string_view>
653 : public __hash_base<size_t, experimental::u32string_view>
656 operator()(const experimental::u32string_view& __s) const noexcept
657 { return std::_Hash_impl::hash(__s.data(),
658 __s.length() * sizeof(char32_t)); }
662 struct __is_fast_hash<hash<experimental::u32string_view>> : std::false_type
665 _GLIBCXX_END_NAMESPACE_VERSION
667 namespace experimental
669 _GLIBCXX_BEGIN_NAMESPACE_VERSION
671 // I added these EMSR.
672 inline namespace literals
674 inline namespace string_view_literals
677 inline basic_string_view<char>
678 operator""sv(const char* __str, size_t __len)
679 { return basic_string_view<char>{__str, __len}; }
681 #ifdef _GLIBCXX_USE_WCHAR_T
682 inline basic_string_view<wchar_t>
683 operator""sv(const wchar_t* __str, size_t __len)
684 { return basic_string_view<wchar_t>{__str, __len}; }
687 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
688 inline basic_string_view<char16_t>
689 operator""sv(const char16_t* __str, size_t __len)
690 { return basic_string_view<char16_t>{__str, __len}; }
692 inline basic_string_view<char32_t>
693 operator""sv(const char32_t* __str, size_t __len)
694 { return basic_string_view<char32_t>{__str, __len}; }
700 _GLIBCXX_END_NAMESPACE_VERSION
701 } // namespace experimental
704 #include <experimental/string_view.tcc>
706 #endif // __cplusplus <= 201103L
708 #endif // _GLIBCXX_EXPERIMENTAL_STRING_VIEW