regex.h source code [include/c++/14/bits/regex.h]

1	// class template regex -- C++ --
2
3	// Copyright (C) 2010-2024 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	/**
26	* @file bits/regex.h
27	* This is an internal header file, included by other library headers.
28	* Do not attempt to use it directly. @headername{regex}
29	*/
30
31	#if __cplusplus >= 202002L
32	# include <bits/iterator_concepts.h> // std::default_sentinel_t
33	#endif
34
35	namespace std _GLIBCXX_VISIBILITY(default)
36	{
37	_GLIBCXX_BEGIN_NAMESPACE_VERSION
38	_GLIBCXX_BEGIN_NAMESPACE_CXX11
39	template<typename, typename>
40	class basic_regex;
41
42	template<typename _Bi_iter, typename _Alloc>
43	class match_results;
44
45	_GLIBCXX_END_NAMESPACE_CXX11
46
47	namespace __detail
48	{
49	enum class _RegexExecutorPolicy : int { _S_auto, _S_alternate };
50
51	template<typename _BiIter, typename _Alloc,
52	typename _CharT, typename _TraitsT>
53	bool
54	__regex_algo_impl(_BiIter __s, _BiIter __e,
55	match_results<_BiIter, _Alloc>& __m,
56	const basic_regex<_CharT, _TraitsT>& __re,
57	regex_constants::match_flag_type __flags,
58	_RegexExecutorPolicy __policy,
59	bool __match_mode);
60
61	template<typename, typename, typename, bool>
62	class _Executor;
63
64	template<typename _Tp>
65	struct __is_contiguous_iter : false_type { };
66
67	template<typename _Tp>
68	struct __is_contiguous_iter<_Tp*> : true_type { };
69
70	template<typename _Tp, typename _Cont>
71	struct __is_contiguous_iter<__gnu_cxx::__normal_iterator<_Tp*, _Cont>>
72	: true_type { };
73	}
74
75	_GLIBCXX_BEGIN_NAMESPACE_CXX11
76
77	/**
78	* @addtogroup regex
79	* @{
80	*/
81
82	/**
83	* @brief Describes aspects of a regular expression.
84	*
85	* A regular expression traits class that satisfies the requirements of
86	* section [28.7].
87	*
88	* The class %regex is parameterized around a set of related types and
89	* functions used to complete the definition of its semantics. This class
90	* satisfies the requirements of such a traits class.
91	*
92	* @headerfile regex
93	* @since C++11
94	*/
95	template<typename _Ch_type>
96	class regex_traits
97	{
98	public:
99	typedef _Ch_type char_type;
100	typedef std::basic_string<char_type> string_type;
101	typedef std::locale locale_type;
102
103	private:
104	struct _RegexMask
105	{
106	typedef std::ctype_base::mask _BaseType;
107	_BaseType _M_base;
108	unsigned char _M_extended;
109	static constexpr unsigned char _S_under = `1` << `0`;
110	static constexpr unsigned char _S_valid_mask = `0x1`;
111
112	constexpr _RegexMask(_BaseType __base = `0`,
113	unsigned char __extended = `0`)
114	: _M_base(__base), _M_extended(__extended)
115	{ }
116
117	constexpr _RegexMask
118	operator&(_RegexMask __other) const
119	{
120	return _RegexMask(_M_base & __other._M_base,
121	_M_extended & __other._M_extended);
122	}
123
124	constexpr _RegexMask
125	operator\|(_RegexMask __other) const
126	{
127	return _RegexMask(_M_base \| __other._M_base,
128	_M_extended \| __other._M_extended);
129	}
130
131	constexpr _RegexMask
132	operator^(_RegexMask __other) const
133	{
134	return _RegexMask(_M_base ^ __other._M_base,
135	_M_extended ^ __other._M_extended);
136	}
137
138	constexpr _RegexMask
139	operator~() const
140	{ return _RegexMask(~_M_base, ~_M_extended); }
141
142	_RegexMask&
143	operator&=(_RegexMask __other)
144	{ return *this = (*this) & __other; }
145
146	_RegexMask&
147	operator\|=(_RegexMask __other)
148	{ return *this = (*this) \| __other; }
149
150	_RegexMask&
151	operator^=(_RegexMask __other)
152	{ return *this = (*this) ^ __other; }
153
154	constexpr bool
155	operator==(_RegexMask __other) const
156	{
157	return (_M_extended & _S_valid_mask)
158	== (__other._M_extended & _S_valid_mask)
159	&& _M_base == __other._M_base;
160	}
161
162	#if __cpp_impl_three_way_comparison < 201907L
163	constexpr bool
164	operator!=(_RegexMask __other) const
165	{ return !((*this) == __other); }
166	#endif
167	};
168
169	public:
170	typedef _RegexMask char_class_type;
171
172	public:
173	/**
174	* @brief Constructs a default traits object.
175	*/
176	regex_traits() { }
177
178	/**
179	* @brief Gives the length of a C-style string starting at @p __p.
180	*
181	* @param __p a pointer to the start of a character sequence.
182	*
183	* @returns the number of characters between @p *__p and the first
184	* default-initialized value of type @p char_type. In other words, uses
185	* the C-string algorithm for determining the length of a sequence of
186	* characters.
187	*/
188	static std::size_t
189	length(const char_type* __p)
190	{ return string_type::traits_type::length(__p); }
191
192	/**
193	* @brief Performs the identity translation.
194	*
195	* @param __c A character to the locale-specific character set.
196	*
197	* @returns __c.
198	*/
199	char_type
200	translate(char_type __c) const
201	{ return __c; }
202
203	/**
204	* @brief Translates a character into a case-insensitive equivalent.
205	*
206	* @param __c A character to the locale-specific character set.
207	*
208	* @returns the locale-specific lower-case equivalent of __c.
209	* @throws std::bad_cast if the imbued locale does not support the ctype
210	* facet.
211	*/
212	char_type
213	translate_nocase(char_type __c) const
214	{
215	typedef std::ctype<char_type> __ctype_type;
216	const __ctype_type& __fctyp(use_facet<__ctype_type>(_M_locale));
217	return __fctyp.tolower(__c);
218	}
219
220	/**
221	* @brief Gets a sort key for a character sequence.
222	*
223	* @param __first beginning of the character sequence.
224	* @param __last one-past-the-end of the character sequence.
225	*
226	* Returns a sort key for the character sequence designated by the
227	* iterator range [F1, F2) such that if the character sequence [G1, G2)
228	* sorts before the character sequence [H1, H2) then
229	* v.transform(G1, G2) < v.transform(H1, H2).
230	*
231	* What this really does is provide a more efficient way to compare a
232	* string to multiple other strings in locales with fancy collation
233	* rules and equivalence classes.
234	*
235	* @returns a locale-specific sort key equivalent to the input range.
236	*
237	* @throws std::bad_cast if the current locale does not have a collate
238	* facet.
239	*/
240	template<typename _Fwd_iter>
241	string_type
242	transform(_Fwd_iter __first, _Fwd_iter __last) const
243	{
244	typedef std::collate<char_type> __collate_type;
245	const __collate_type& __fclt(use_facet<__collate_type>(_M_locale));
246	string_type __s(__first, __last);
247	return __fclt.transform(__s.data(), __s.data() + __s.size());
248	}
249
250	/**
251	* @brief Gets a sort key for a character sequence, independent of case.
252	*
253	* @param __first beginning of the character sequence.
254	* @param __last one-past-the-end of the character sequence.
255	*
256	* Effects: if typeid(use_facet<collate<_Ch_type> >) ==
257	* typeid(collate_byname<_Ch_type>) and the form of the sort key
258	* returned by collate_byname<_Ch_type>::transform(__first, __last)
259	* is known and can be converted into a primary sort key
260	* then returns that key, otherwise returns an empty string.
261	*
262	* @todo Implement this function correctly.
263	*/
264	template<typename _Fwd_iter>
265	string_type
266	transform_primary(_Fwd_iter __first, _Fwd_iter __last) const
267	{
268	// TODO : this is not entirely correct.
269	// This function requires extra support from the platform.
270	//
271	// Read http://gcc.gnu.org/ml/libstdc++/2013-09/msg00117.html and
272	// http://www.open-std.org/Jtc1/sc22/wg21/docs/papers/2003/n1429.htm
273	// for details.
274	typedef std::ctype<char_type> __ctype_type;
275	const __ctype_type& __fctyp(use_facet<__ctype_type>(_M_locale));
276	_GLIBCXX_STD_C::vector<char_type> __s(__first, __last);
277	__fctyp.tolower(__s.data(), __s.data() + __s.size());
278	return this->transform(__s.data(), __s.data() + __s.size());
279	}
280
281	/**
282	* @brief Gets a collation element by name.
283	*
284	* @param __first beginning of the collation element name.
285	* @param __last one-past-the-end of the collation element name.
286	*
287	* @returns a sequence of one or more characters that represents the
288	* collating element consisting of the character sequence designated by
289	* the iterator range [__first, __last). Returns an empty string if the
290	* character sequence is not a valid collating element.
291	*/
292	template<typename _Fwd_iter>
293	string_type
294	lookup_collatename(_Fwd_iter __first, _Fwd_iter __last) const;
295
296	/**
297	* @brief Maps one or more characters to a named character
298	* classification.
299	*
300	* @param __first beginning of the character sequence.
301	* @param __last one-past-the-end of the character sequence.
302	* @param __icase ignores the case of the classification name.
303	*
304	* @returns an unspecified value that represents the character
305	* classification named by the character sequence designated by
306	* the iterator range [__first, __last). If @p icase is true,
307	* the returned mask identifies the classification regardless of
308	* the case of the characters to be matched (for example,
309	* [[:lower:]] is the same as [[:alpha:]]), otherwise a
310	* case-dependent classification is returned. The value
311	* returned shall be independent of the case of the characters
312	* in the character sequence. If the name is not recognized then
313	* returns a value that compares equal to 0.
314	*
315	* At least the following names (or their wide-character equivalent) are
316	* supported.
317	* - d
318	* - w
319	* - s
320	* - alnum
321	* - alpha
322	* - blank
323	* - cntrl
324	* - digit
325	* - graph
326	* - lower
327	* - print
328	* - punct
329	* - space
330	* - upper
331	* - xdigit
332	*/
333	template<typename _Fwd_iter>
334	char_class_type
335	lookup_classname(_Fwd_iter __first, _Fwd_iter __last,
336	bool __icase = false) const;
337
338	/**
339	* @brief Determines if @p c is a member of an identified class.
340	*
341	* @param __c a character.
342	* @param __f a class type (as returned from lookup_classname).
343	*
344	* @returns true if the character @p __c is a member of the classification
345	* represented by @p __f, false otherwise.
346	*
347	* @throws std::bad_cast if the current locale does not have a ctype
348	* facet.
349	*/
350	bool
351	isctype(_Ch_type __c, char_class_type __f) const;
352
353	/**
354	* @brief Converts a digit to an int.
355	*
356	* @param __ch a character representing a digit.
357	* @param __radix the radix if the numeric conversion (limited to 8, 10,
358	* or 16).
359	*
360	* @returns the value represented by the digit __ch in base radix if the
361	* character __ch is a valid digit in base radix; otherwise returns -1.
362	*/
363	int
364	value(_Ch_type __ch, int __radix) const;
365
366	/**
367	* @brief Imbues the regex_traits object with a copy of a new locale.
368	*
369	* @param __loc A locale.
370	*
371	* @returns a copy of the previous locale in use by the regex_traits
372	* object.
373	*
374	* @note Calling imbue with a different locale than the one currently in
375	* use invalidates all cached data held by *this.
376	*/
377	locale_type
378	imbue(locale_type __loc)
379	{
380	std::swap(a&: _M_locale, b&: __loc);
381	return __loc;
382	}
383
384	/**
385	* @brief Gets a copy of the current locale in use by the regex_traits
386	* object.
387	*/
388	locale_type
389	getloc() const
390	{ return _M_locale; }
391
392	protected:
393	locale_type _M_locale;
394	};
395
396	// [7.8] Class basic_regex
397	/**
398	* @brief A regular expression
399	*
400	* Specializations of this class template represent regular expressions
401	* constructed from sequences of character type `_Ch_type`.
402	* Use the `std::regex` typedef for `std::basic_regex<char>`.
403	*
404	* A character sequence passed to the constructor will be parsed according
405	* to the chosen grammar, and used to create a state machine representing
406	* the regular expression. The regex object can then be passed to algorithms
407	* such as `std::regex_match` to match sequences of characters.
408	*
409	* The `syntax_option_type` flag passed to the constructor selects from
410	* one of the supported regular expression grammars. The default is
411	* `ECMAScript` and the others are `basic`, `extended`, `awk`, `grep`, and
412	* `egrep`, which are variations on POSIX regular expressions.
413	*
414	* @headerfile regex
415	* @since C++11
416	*/
417	template<typename _Ch_type, typename _Rx_traits = regex_traits<_Ch_type>>
418	class basic_regex
419	{
420	public:
421	static_assert(is_same<_Ch_type, typename _Rx_traits::char_type>::value,
422	"regex traits class must have the same char_type");
423
424	// types:
425	typedef _Ch_type value_type;
426	typedef _Rx_traits traits_type;
427	typedef typename traits_type::string_type string_type;
428	typedef regex_constants::syntax_option_type flag_type;
429	typedef typename traits_type::locale_type locale_type;
430
431	/**
432	* @name Constants
433	* std [28.8.1](1)
434	*/
435	///@{
436	static constexpr flag_type icase = regex_constants::icase;
437	static constexpr flag_type nosubs = regex_constants::nosubs;
438	static constexpr flag_type optimize = regex_constants::optimize;
439	static constexpr flag_type collate = regex_constants::collate;
440	static constexpr flag_type ECMAScript = regex_constants::ECMAScript;
441	static constexpr flag_type basic = regex_constants::basic;
442	static constexpr flag_type extended = regex_constants::extended;
443	static constexpr flag_type awk = regex_constants::awk;
444	static constexpr flag_type grep = regex_constants::grep;
445	static constexpr flag_type egrep = regex_constants::egrep;
446	#if __cplusplus >= 201703L \|\| !defined __STRICT_ANSI__
447	static constexpr flag_type multiline = regex_constants::multiline;
448	#endif
449	///@}
450
451	// [7.8.2] construct/copy/destroy
452	/**
453	* Constructs a basic regular expression that does not match any
454	* character sequence.
455	*/
456	basic_regex() noexcept
457	: _M_flags(ECMAScript), _M_loc(), _M_automaton(nullptr)
458	{ }
459
460	/**
461	* @brief Constructs a basic regular expression from the
462	* sequence [__p, __p + char_traits<_Ch_type>::length(__p))
463	* interpreted according to the flags in @p __f.
464	*
465	* @param __p A pointer to the start of a C-style null-terminated string
466	* containing a regular expression.
467	* @param __f Flags indicating the syntax rules and options.
468	*
469	* @throws regex_error if @p __p is not a valid regular expression.
470	*/
471	explicit
472	basic_regex(const _Ch_type* __p, flag_type __f = ECMAScript)
473	{ _M_compile(first: __p, last: __p + _Rx_traits::length(__p), __f); }
474
475	/**
476	* @brief Constructs a basic regular expression from the sequence
477	* [p, p + len) interpreted according to the flags in @p f.
478	*
479	* @param __p A pointer to the start of a string containing a regular
480	* expression.
481	* @param __len The length of the string containing the regular
482	* expression.
483	* @param __f Flags indicating the syntax rules and options.
484	*
485	* @throws regex_error if @p __p is not a valid regular expression.
486	*/
487	basic_regex(const _Ch_type* __p, std::size_t __len,
488	flag_type __f = ECMAScript)
489	{
490	__glibcxx_requires_string_len(__p, __len);
491	_M_compile(first: __p, last: __p + __len, __f);
492	}
493
494	/**
495	* @brief Copy-constructs a basic regular expression.
496	*
497	* @param __rhs A @p regex object.
498	*/
499	basic_regex(const basic_regex& __rhs) = default;
500
501	/**
502	* @brief Move-constructs a basic regular expression.
503	*
504	* @param __rhs A @p regex object.
505	*/
506	basic_regex(basic_regex&& __rhs) noexcept = default;
507
508	/**
509	* @brief Constructs a basic regular expression from the string
510	* @p s interpreted according to the flags in @p f.
511	*
512	* @param __s A string containing a regular expression.
513	* @param __f Flags indicating the syntax rules and options.
514	*
515	* @throws regex_error if @p __s is not a valid regular expression.
516	*/
517	template<typename _Ch_traits, typename _Ch_alloc>
518	explicit
519	basic_regex(const std::basic_string<_Ch_type, _Ch_traits,
520	_Ch_alloc>& __s,
521	flag_type __f = ECMAScript)
522	{ _M_compile(first: __s.data(), last: __s.data() + __s.size(), __f); }
523
524	/**
525	* @brief Constructs a basic regular expression from the range
526	* [first, last) interpreted according to the flags in @p f.
527	*
528	* @param __first The start of a range containing a valid regular
529	* expression.
530	* @param __last The end of a range containing a valid regular
531	* expression.
532	* @param __f The format flags of the regular expression.
533	*
534	* @throws regex_error if @p [__first, __last) is not a valid regular
535	* expression.
536	*/
537	template<typename _FwdIter>
538	basic_regex(_FwdIter __first, _FwdIter __last,
539	flag_type __f = ECMAScript)
540	{ this->assign(__first, __last, __f); }
541
542	/**
543	* @brief Constructs a basic regular expression from an initializer list.
544	*
545	* @param __l The initializer list.
546	* @param __f The format flags of the regular expression.
547	*
548	* @throws regex_error if @p __l is not a valid regular expression.
549	*/
550	basic_regex(initializer_list<_Ch_type> __l, flag_type __f = ECMAScript)
551	{ _M_compile(first: __l.begin(), last: __l.end(), __f); }
552
553	/**
554	* @brief Destroys a basic regular expression.
555	*/
556	~basic_regex()
557	{ }
558
559	/**
560	* @brief Assigns one regular expression to another.
561	*/
562	basic_regex&
563	operator=(const basic_regex&) = default;
564
565	/**
566	* @brief Move-assigns one regular expression to another.
567	*/
568	basic_regex&
569	operator=(basic_regex&&) = default;
570
571	/**
572	* @brief Replaces a regular expression with a new one constructed from
573	* a C-style null-terminated string.
574	*
575	* @param __p A pointer to the start of a null-terminated C-style string
576	* containing a regular expression.
577	*/
578	basic_regex&
579	operator=(const _Ch_type* __p)
580	{ return this->assign(__p); }
581
582	/**
583	* @brief Replaces a regular expression with a new one constructed from
584	* an initializer list.
585	*
586	* @param __l The initializer list.
587	*
588	* @throws regex_error if @p __l is not a valid regular expression.
589	*/
590	basic_regex&
591	operator=(initializer_list<_Ch_type> __l)
592	{ return this->assign(__l); }
593
594	/**
595	* @brief Replaces a regular expression with a new one constructed from
596	* a string.
597	*
598	* @param __s A pointer to a string containing a regular expression.
599	*/
600	template<typename _Ch_traits, typename _Alloc>
601	basic_regex&
602	operator=(const basic_string<_Ch_type, _Ch_traits, _Alloc>& __s)
603	{ return this->assign(__s); }
604
605	// [7.8.3] assign
606	/**
607	* @brief Assigns one regular expression to another.
608	*
609	* @param __rhs Another regular expression object.
610	*/
611	basic_regex&
612	assign(const basic_regex& __rhs) noexcept
613	{ return *this = __rhs; }
614
615	/**
616	* @brief Move-assigns one regular expression to another.
617	*
618	* @param __rhs Another regular expression object.
619	*/
620	basic_regex&
621	assign(basic_regex&& __rhs) noexcept
622	{ return *this = std::move(__rhs); }
623
624	/**
625	* @brief Assigns a new regular expression to a regex object from a
626	* C-style null-terminated string containing a regular expression
627	* pattern.
628	*
629	* @param __p A pointer to a C-style null-terminated string containing
630	* a regular expression pattern.
631	* @param __flags Syntax option flags.
632	*
633	* @throws regex_error if __p does not contain a valid regular
634	* expression pattern interpreted according to @p __flags. If
635	* regex_error is thrown, *this remains unchanged.
636	*/
637	basic_regex&
638	assign(const _Ch_type* __p, flag_type __flags = ECMAScript)
639	{
640	_M_compile(first: __p, last: __p + _Rx_traits::length(__p), f: __flags);
641	return *this;
642	}
643
644	/**
645	* @brief Assigns a new regular expression to a regex object from a
646	* C-style string containing a regular expression pattern.
647	*
648	* @param __p A pointer to a C-style string containing a
649	* regular expression pattern.
650	* @param __len The length of the regular expression pattern string.
651	* @param __flags Syntax option flags.
652	*
653	* @throws regex_error if p does not contain a valid regular
654	* expression pattern interpreted according to @p __flags. If
655	* regex_error is thrown, *this remains unchanged.
656	*/
657	// _GLIBCXX_RESOLVE_LIB_DEFECTS
658	// 3296. Inconsistent default argument for basic_regex<>::assign
659	basic_regex&
660	assign(const _Ch_type* __p, size_t __len, flag_type __flags = ECMAScript)
661	{
662	_M_compile(first: __p, last: __p + __len, f: __flags);
663	return *this;
664	}
665
666	/**
667	* @brief Assigns a new regular expression to a regex object from a
668	* string containing a regular expression pattern.
669	*
670	* @param __s A string containing a regular expression pattern.
671	* @param __flags Syntax option flags.
672	*
673	* @throws regex_error if __s does not contain a valid regular
674	* expression pattern interpreted according to @p __flags. If
675	* regex_error is thrown, *this remains unchanged.
676	*/
677	template<typename _Ch_traits, typename _Alloc>
678	basic_regex&
679	assign(const basic_string<_Ch_type, _Ch_traits, _Alloc>& __s,
680	flag_type __flags = ECMAScript)
681	{
682	_M_compile(first: __s.data(), last: __s.data() + __s.size(), f: __flags);
683	return *this;
684	}
685
686	/**
687	* @brief Assigns a new regular expression to a regex object.
688	*
689	* @param __first The start of a range containing a valid regular
690	* expression.
691	* @param __last The end of a range containing a valid regular
692	* expression.
693	* @param __flags Syntax option flags.
694	*
695	* @throws regex_error if p does not contain a valid regular
696	* expression pattern interpreted according to @p __flags. If
697	* regex_error is thrown, the object remains unchanged.
698	*/
699	template<typename _InputIterator>
700	basic_regex&
701	assign(_InputIterator __first, _InputIterator __last,
702	flag_type __flags = ECMAScript)
703	{
704	#if __cpp_if_constexpr >= 201606L
705	using _ValT = typename iterator_traits<_InputIterator>::value_type;
706	if constexpr (__detail::__is_contiguous_iter<_InputIterator>::value
707	&& is_same_v<_ValT, value_type>)
708	{
709	__glibcxx_requires_valid_range(__first, __last);
710	if constexpr (is_pointer_v<_InputIterator>)
711	_M_compile(__first, __last, f: __flags);
712	else // __normal_iterator<_T, C>*
713	_M_compile(first: __first.base(), last: __last.base(), f: __flags);
714	}
715	else
716	#endif
717	this->assign(string_type(__first, __last), __flags);
718	return *this;
719	}
720
721	/**
722	* @brief Assigns a new regular expression to a regex object.
723	*
724	* @param __l An initializer list representing a regular expression.
725	* @param __flags Syntax option flags.
726	*
727	* @throws regex_error if @p __l does not contain a valid
728	* regular expression pattern interpreted according to @p
729	* __flags. If regex_error is thrown, the object remains
730	* unchanged.
731	*/
732	basic_regex&
733	assign(initializer_list<_Ch_type> __l, flag_type __flags = ECMAScript)
734	{
735	_M_compile(first: __l.begin(), last: __l.end(), f: __flags);
736	return *this;
737	}
738
739	// [7.8.4] const operations
740	/**
741	* @brief Gets the number of marked subexpressions within the regular
742	* expression.
743	*/
744	unsigned int
745	mark_count() const noexcept
746	{
747	if (_M_automaton)
748	return _M_automaton->_M_sub_count() - `1`;
749	return `0`;
750	}
751
752	/**
753	* @brief Gets the flags used to construct the regular expression
754	* or in the last call to assign().
755	*/
756	flag_type
757	flags() const noexcept
758	{ return _M_flags; }
759
760	// [7.8.5] locale
761	/**
762	* @brief Imbues the regular expression object with the given locale.
763	*
764	* @param __loc A locale.
765	*/
766	locale_type
767	imbue(locale_type __loc)
768	{
769	std::swap(__loc, _M_loc);
770	_M_automaton.reset();
771	return __loc;
772	}
773
774	/**
775	* @brief Gets the locale currently imbued in the regular expression
776	* object.
777	*/
778	locale_type
779	getloc() const noexcept
780	{ return _M_loc; }
781
782	// [7.8.6] swap
783	/**
784	* @brief Swaps the contents of two regular expression objects.
785	*
786	* @param __rhs Another regular expression object.
787	*/
788	void
789	swap(basic_regex& __rhs) noexcept
790	{
791	std::swap(_M_flags, __rhs._M_flags);
792	std::swap(_M_loc, __rhs._M_loc);
793	std::swap(_M_automaton, __rhs._M_automaton);
794	}
795
796	#ifdef _GLIBCXX_DEBUG
797	void
798	_M_dot(std::ostream& __ostr)
799	{ _M_automaton->_M_dot(__ostr); }
800	#endif
801
802	private:
803	typedef std::shared_ptr<const __detail::_NFA<_Rx_traits>> _AutomatonPtr;
804
805	void
806	_M_compile(const _Ch_type* __first, const _Ch_type* __last,
807	flag_type __f)
808	{
809	__detail::_Compiler<_Rx_traits> __c(__first, __last, _M_loc, __f);
810	_M_automaton = __c._M_get_nfa();
811	_M_flags = __f;
812	}
813
814	template<typename _Bp, typename _Ap, typename _Cp, typename _Rp>
815	friend bool
816	__detail::__regex_algo_impl(_Bp, _Bp, match_results<_Bp, _Ap>&,
817	const basic_regex<_Cp, _Rp>&,
818	regex_constants::match_flag_type,
819	__detail::_RegexExecutorPolicy, bool);
820
821	template<typename, typename, typename, bool>
822	friend class __detail::_Executor;
823
824	flag_type _M_flags;
825	locale_type _M_loc;
826	_AutomatonPtr _M_automaton;
827	};
828
829	#if ! __cpp_inline_variables
830	template<typename _Ch, typename _Tr>
831	constexpr regex_constants::syntax_option_type
832	basic_regex<_Ch, _Tr>::icase;
833
834	template<typename _Ch, typename _Tr>
835	constexpr regex_constants::syntax_option_type
836	basic_regex<_Ch, _Tr>::nosubs;
837
838	template<typename _Ch, typename _Tr>
839	constexpr regex_constants::syntax_option_type
840	basic_regex<_Ch, _Tr>::optimize;
841
842	template<typename _Ch, typename _Tr>
843	constexpr regex_constants::syntax_option_type
844	basic_regex<_Ch, _Tr>::collate;
845
846	template<typename _Ch, typename _Tr>
847	constexpr regex_constants::syntax_option_type
848	basic_regex<_Ch, _Tr>::ECMAScript;
849
850	template<typename _Ch, typename _Tr>
851	constexpr regex_constants::syntax_option_type
852	basic_regex<_Ch, _Tr>::basic;
853
854	template<typename _Ch, typename _Tr>
855	constexpr regex_constants::syntax_option_type
856	basic_regex<_Ch, _Tr>::extended;
857
858	template<typename _Ch, typename _Tr>
859	constexpr regex_constants::syntax_option_type
860	basic_regex<_Ch, _Tr>::awk;
861
862	template<typename _Ch, typename _Tr>
863	constexpr regex_constants::syntax_option_type
864	basic_regex<_Ch, _Tr>::grep;
865
866	template<typename _Ch, typename _Tr>
867	constexpr regex_constants::syntax_option_type
868	basic_regex<_Ch, _Tr>::egrep;
869	#endif // ! C++17
870
871	#if __cpp_deduction_guides >= 201606
872	template<typename _ForwardIterator>
873	basic_regex(_ForwardIterator, _ForwardIterator,
874	regex_constants::syntax_option_type = {})
875	-> basic_regex<typename iterator_traits<_ForwardIterator>::value_type>;
876	#endif
877
878	/* @brief Standard regular expressions. /
879	typedef basic_regex<char> regex;
880
881	#ifdef _GLIBCXX_USE_WCHAR_T
882	/* @brief Standard wide-character regular expressions. /
883	typedef basic_regex<wchar_t> wregex;
884	#endif
885
886
887	// [7.8.6] basic_regex swap
888	/**
889	* @brief Swaps the contents of two regular expression objects.
890	* @param __lhs First regular expression.
891	* @param __rhs Second regular expression.
892	* @relates basic_regex
893	*/
894	template<typename _Ch_type, typename _Rx_traits>
895	inline void
896	swap(basic_regex<_Ch_type, _Rx_traits>& __lhs,
897	basic_regex<_Ch_type, _Rx_traits>& __rhs) noexcept
898	{ __lhs.swap(__rhs); }
899
900
901	// C++11 28.9 [re.submatch] Class template sub_match
902	/**
903	* A sequence of characters matched by a particular marked sub-expression.
904	*
905	* An object of this class is essentially a pair of iterators marking a
906	* matched subexpression within a regular expression pattern match. Such
907	* objects can be converted to and compared with std::basic_string objects
908	* of the same character type as the pattern matched by the regular
909	* expression.
910	*
911	* A `sub_match<Iter>` has a public base class of type `pair<Iter, Iter>`,
912	* so inherits pair's data members named `first` and `second`.
913	* The iterators that make up the pair are the usual half-open interval
914	* referencing the actual original pattern matched.
915	*
916	* @headerfile regex
917	* @since C++11
918	*/
919	template<typename _BiIter>
920	class sub_match
921	/// @cond undocumented
922	: public std::pair<_BiIter, _BiIter>
923	/// @endcond
924	{
925	typedef iterator_traits<_BiIter> __iter_traits;
926
927	public:
928	typedef typename __iter_traits::value_type value_type;
929	typedef typename __iter_traits::difference_type difference_type;
930	typedef _BiIter iterator;
931	typedef basic_string<value_type> string_type;
932
933	_GLIBCXX_DOXYGEN_ONLY(iterator first; iterator second;)
934
935	bool matched;
936
937	constexpr sub_match() noexcept : matched() { }
938
939	/// Gets the length of the matching sequence.
940	difference_type
941	length() const noexcept
942	{ return this->matched ? std::distance(this->first, this->second) : `0`; }
943
944	/**
945	* @brief Gets the matching sequence as a string.
946	*
947	* @returns the matching sequence as a string.
948	*
949	* This is the implicit conversion operator. It is identical to the
950	* str() member function except that it will want to pop up in
951	* unexpected places and cause a great deal of confusion and cursing
952	* from the unwary.
953	*/
954	operator string_type() const
955	{ return str(); }
956
957	/**
958	* @brief Gets the matching sequence as a string.
959	*
960	* @returns the matching sequence as a string.
961	*/
962	string_type
963	str() const
964	{
965	return this->matched
966	? string_type(this->first, this->second)
967	: string_type();
968	}
969
970	/**
971	* @brief Compares this and another matched sequence.
972	*
973	* @param __s Another matched sequence to compare to this one.
974	*
975	* @retval negative This matched sequence will collate before `__s`.
976	* @retval zero This matched sequence is equivalent to `__s`.
977	* @retval positive This matched sequence will collate after `__s`.
978	*/
979	int
980	compare(const sub_match& __s) const
981	{ return this->_M_str().compare(__s._M_str()); }
982
983	/**
984	* @{
985	* @brief Compares this `sub_match` to a string.
986	*
987	* @param __s A string to compare to this `sub_match`.
988	*
989	* @retval negative This matched sequence will collate before `__s`.
990	* @retval zero This matched sequence is equivalent to `__s`.
991	* @retval positive This matched sequence will collate after `__s`.
992	*/
993	int
994	compare(const string_type& __s) const
995	{ return this->_M_str().compare(__s); }
996
997	int
998	compare(const value_type* __s) const
999	{ return this->_M_str().compare(__s); }
1000	/// @}
1001
1002	/// @cond undocumented
1003	// Non-standard, used by comparison operators
1004	int
1005	_M_compare(const value_type* __s, size_t __n) const
1006	{ return this->_M_str().compare({__s, __n}); }
1007	/// @endcond
1008
1009	// _GLIBCXX_RESOLVE_LIB_DEFECTS
1010	// 3204. sub_match::swap only swaps the base class
1011	/// Swap the values of two sub_match objects.
1012	void
1013	swap(sub_match& __s) noexcept(__is_nothrow_swappable<_BiIter>::value)
1014	{
1015	this->pair<_BiIter, _BiIter>::swap(__s);
1016	std::swap(matched, __s.matched);
1017	}
1018
1019	private:
1020	// Simplified basic_string_view for C++11
1021	struct __string_view
1022	{
1023	using traits_type = typename string_type::traits_type;
1024
1025	__string_view() = default;
1026
1027	__string_view(const value_type* __s, size_t __n) noexcept
1028	: _M_data(__s), _M_len(__n) { }
1029
1030	__string_view(const value_type* __s) noexcept
1031	: _M_data(__s), _M_len(traits_type::length(__s)) { }
1032
1033	__string_view(const string_type& __s) noexcept
1034	: _M_data(__s.data()), _M_len(__s.length()) { }
1035
1036	int
1037	compare(__string_view __s) const noexcept
1038	{
1039	if (const size_t __n = std::min(_M_len, __s._M_len))
1040	if (int __ret = traits_type::compare(_M_data, __s._M_data, __n))
1041	return __ret;
1042	using __limits = __gnu_cxx::__int_traits<int>;
1043	const difference_type __diff = _M_len - __s._M_len;
1044	if (__diff > __limits::__max)
1045	return __limits::__max;
1046	if (__diff < __limits::__min)
1047	return __limits::__min;
1048	return static_cast<int>(__diff);
1049	}
1050
1051	private:
1052	const value_type* _M_data = nullptr;
1053	size_t _M_len = `0`;
1054	};
1055
1056	// Create a __string_view over the iterator range.
1057	template<typename _Iter = _BiIter>
1058	__enable_if_t<__detail::__is_contiguous_iter<_Iter>::value,
1059	__string_view>
1060	_M_str() const noexcept
1061	{
1062	if (this->matched)
1063	if (size_t __len = this->second - this->first)
1064	return { std::__addressof(*this->first), __len };
1065	return {};
1066	}
1067
1068	// Create a temporary string that can be converted to __string_view.
1069	template<typename _Iter = _BiIter>
1070	__enable_if_t<!__detail::__is_contiguous_iter<_Iter>::value,
1071	string_type>
1072	_M_str() const
1073	{ return str(); }
1074	};
1075
1076
1077	/* @brief Standard regex submatch over a C-style null-terminated string. /
1078	typedef sub_match<const char*> csub_match;
1079
1080	/* @brief Standard regex submatch over a standard string. /
1081	typedef sub_match<string::const_iterator> ssub_match;
1082
1083	#ifdef _GLIBCXX_USE_WCHAR_T
1084	/* @brief Regex submatch over a C-style null-terminated wide string. /
1085	typedef sub_match<const wchar_t*> wcsub_match;
1086
1087	/* @brief Regex submatch over a standard wide string. /
1088	typedef sub_match<wstring::const_iterator> wssub_match;
1089	#endif
1090
1091	// [7.9.2] sub_match non-member operators
1092
1093	/// @relates sub_match @{
1094
1095	/**
1096	* @brief Tests the equivalence of two regular expression submatches.
1097	* @param __lhs First regular expression submatch.
1098	* @param __rhs Second regular expression submatch.
1099	* @returns true if @a __lhs is equivalent to @a __rhs, false otherwise.
1100	*/
1101	template<typename _BiIter>
1102	inline bool
1103	operator==(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
1104	{ return __lhs.compare(__rhs) == `0`; }
1105
1106	#if __cpp_lib_three_way_comparison
1107	/**
1108	* @brief Three-way comparison of two regular expression submatches.
1109	* @param __lhs First regular expression submatch.
1110	* @param __rhs Second regular expression submatch.
1111	* @returns A value indicating whether `__lhs` is less than, equal to,
1112	* greater than, or incomparable with `__rhs`.
1113	*/
1114	template<typename _BiIter>
1115	inline auto
1116	operator<=>(const sub_match<_BiIter>& __lhs,
1117	const sub_match<_BiIter>& __rhs)
1118	noexcept(__detail::__is_contiguous_iter<_BiIter>::value)
1119	{
1120	using _Tr = char_traits<typename iterator_traits<_BiIter>::value_type>;
1121	return __detail::__char_traits_cmp_cat<_Tr>(__lhs.compare(__rhs));
1122	}
1123	#else
1124	/**
1125	* @brief Tests the inequivalence of two regular expression submatches.
1126	* @param __lhs First regular expression submatch.
1127	* @param __rhs Second regular expression submatch.
1128	* @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
1129	*/
1130	template<typename _BiIter>
1131	inline bool
1132	operator!=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
1133	{ return __lhs.compare(__rhs) != `0`; }
1134
1135	/**
1136	* @brief Tests the ordering of two regular expression submatches.
1137	* @param __lhs First regular expression submatch.
1138	* @param __rhs Second regular expression submatch.
1139	* @returns true if @a __lhs precedes @a __rhs, false otherwise.
1140	*/
1141	template<typename _BiIter>
1142	inline bool
1143	operator<(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
1144	{ return __lhs.compare(__rhs) < `0`; }
1145
1146	/**
1147	* @brief Tests the ordering of two regular expression submatches.
1148	* @param __lhs First regular expression submatch.
1149	* @param __rhs Second regular expression submatch.
1150	* @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
1151	*/
1152	template<typename _BiIter>
1153	inline bool
1154	operator<=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
1155	{ return __lhs.compare(__rhs) <= `0`; }
1156
1157	/**
1158	* @brief Tests the ordering of two regular expression submatches.
1159	* @param __lhs First regular expression submatch.
1160	* @param __rhs Second regular expression submatch.
1161	* @returns true if @a __lhs does not precede @a __rhs, false otherwise.
1162	*/
1163	template<typename _BiIter>
1164	inline bool
1165	operator>=(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
1166	{ return __lhs.compare(__rhs) >= `0`; }
1167
1168	/**
1169	* @brief Tests the ordering of two regular expression submatches.
1170	* @param __lhs First regular expression submatch.
1171	* @param __rhs Second regular expression submatch.
1172	* @returns true if @a __lhs succeeds @a __rhs, false otherwise.
1173	*/
1174	template<typename _BiIter>
1175	inline bool
1176	operator>(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
1177	{ return __lhs.compare(__rhs) > `0`; }
1178	#endif // three-way comparison
1179
1180	/// @cond undocumented
1181
1182	// Alias for a basic_string that can be compared to a sub_match.
1183	template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
1184	using __sub_match_string = basic_string<
1185	typename iterator_traits<_Bi_iter>::value_type,
1186	_Ch_traits, _Ch_alloc>;
1187	/// @endcond
1188
1189	#if ! __cpp_lib_three_way_comparison
1190	/**
1191	* @brief Tests the equivalence of a string and a regular expression
1192	* submatch.
1193	* @param __lhs A string.
1194	* @param __rhs A regular expression submatch.
1195	* @returns true if @a __lhs is equivalent to @a __rhs, false otherwise.
1196	*/
1197	template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
1198	inline bool
1199	operator==(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
1200	const sub_match<_Bi_iter>& __rhs)
1201	{ return __rhs._M_compare(__lhs.data(), __lhs.size()) == `0`; }
1202
1203	/**
1204	* @brief Tests the inequivalence of a string and a regular expression
1205	* submatch.
1206	* @param __lhs A string.
1207	* @param __rhs A regular expression submatch.
1208	* @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
1209	*/
1210	template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
1211	inline bool
1212	operator!=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
1213	const sub_match<_Bi_iter>& __rhs)
1214	{ return !(__lhs == __rhs); }
1215
1216	/**
1217	* @brief Tests the ordering of a string and a regular expression submatch.
1218	* @param __lhs A string.
1219	* @param __rhs A regular expression submatch.
1220	* @returns true if @a __lhs precedes @a __rhs, false otherwise.
1221	*/
1222	template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
1223	inline bool
1224	operator<(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
1225	const sub_match<_Bi_iter>& __rhs)
1226	{ return __rhs._M_compare(__lhs.data(), __lhs.size()) > `0`; }
1227
1228	/**
1229	* @brief Tests the ordering of a string and a regular expression submatch.
1230	* @param __lhs A string.
1231	* @param __rhs A regular expression submatch.
1232	* @returns true if @a __lhs succeeds @a __rhs, false otherwise.
1233	*/
1234	template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
1235	inline bool
1236	operator>(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
1237	const sub_match<_Bi_iter>& __rhs)
1238	{ return __rhs < __lhs; }
1239
1240	/**
1241	* @brief Tests the ordering of a string and a regular expression submatch.
1242	* @param __lhs A string.
1243	* @param __rhs A regular expression submatch.
1244	* @returns true if @a __lhs does not precede @a __rhs, false otherwise.
1245	*/
1246	template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
1247	inline bool
1248	operator>=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
1249	const sub_match<_Bi_iter>& __rhs)
1250	{ return !(__lhs < __rhs); }
1251
1252	/**
1253	* @brief Tests the ordering of a string and a regular expression submatch.
1254	* @param __lhs A string.
1255	* @param __rhs A regular expression submatch.
1256	* @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
1257	*/
1258	template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
1259	inline bool
1260	operator<=(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
1261	const sub_match<_Bi_iter>& __rhs)
1262	{ return !(__rhs < __lhs); }
1263	#endif // three-way comparison
1264
1265	/**
1266	* @brief Tests the equivalence of a regular expression submatch and a
1267	* string.
1268	* @param __lhs A regular expression submatch.
1269	* @param __rhs A string.
1270	* @returns true if @a __lhs is equivalent to @a __rhs, false otherwise.
1271	*/
1272	template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
1273	inline bool
1274	operator==(const sub_match<_Bi_iter>& __lhs,
1275	const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
1276	{ return __lhs._M_compare(__rhs.data(), __rhs.size()) == `0`; }
1277
1278	#if __cpp_lib_three_way_comparison
1279	/**
1280	* @brief Three-way comparison of a regular expression submatch and a string.
1281	* @param __lhs A regular expression submatch.
1282	* @param __rhs A string.
1283	* @returns A value indicating whether `__lhs` is less than, equal to,
1284	* greater than, or incomparable with `__rhs`.
1285	*/
1286	template<typename _Bi_iter, typename _Ch_traits, typename _Alloc>
1287	inline auto
1288	operator<=>(const sub_match<_Bi_iter>& __lhs,
1289	const __sub_match_string<_Bi_iter, _Ch_traits, _Alloc>& __rhs)
1290	noexcept(__detail::__is_contiguous_iter<_Bi_iter>::value)
1291	{
1292	return __detail::__char_traits_cmp_cat<_Ch_traits>(
1293	__lhs._M_compare(__rhs.data(), __rhs.size()));
1294	}
1295	#else
1296	/**
1297	* @brief Tests the inequivalence of a regular expression submatch and a
1298	* string.
1299	* @param __lhs A regular expression submatch.
1300	* @param __rhs A string.
1301	* @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
1302	*/
1303	template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
1304	inline bool
1305	operator!=(const sub_match<_Bi_iter>& __lhs,
1306	const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
1307	{ return !(__lhs == __rhs); }
1308
1309	/**
1310	* @brief Tests the ordering of a regular expression submatch and a string.
1311	* @param __lhs A regular expression submatch.
1312	* @param __rhs A string.
1313	* @returns true if @a __lhs precedes @a __rhs, false otherwise.
1314	*/
1315	template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
1316	inline bool
1317	operator<(const sub_match<_Bi_iter>& __lhs,
1318	const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
1319	{ return __lhs._M_compare(__rhs.data(), __rhs.size()) < `0`; }
1320
1321	/**
1322	* @brief Tests the ordering of a regular expression submatch and a string.
1323	* @param __lhs A regular expression submatch.
1324	* @param __rhs A string.
1325	* @returns true if @a __lhs succeeds @a __rhs, false otherwise.
1326	*/
1327	template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
1328	inline bool
1329	operator>(const sub_match<_Bi_iter>& __lhs,
1330	const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
1331	{ return __rhs < __lhs; }
1332
1333	/**
1334	* @brief Tests the ordering of a regular expression submatch and a string.
1335	* @param __lhs A regular expression submatch.
1336	* @param __rhs A string.
1337	* @returns true if @a __lhs does not precede @a __rhs, false otherwise.
1338	*/
1339	template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
1340	inline bool
1341	operator>=(const sub_match<_Bi_iter>& __lhs,
1342	const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
1343	{ return !(__lhs < __rhs); }
1344
1345	/**
1346	* @brief Tests the ordering of a regular expression submatch and a string.
1347	* @param __lhs A regular expression submatch.
1348	* @param __rhs A string.
1349	* @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
1350	*/
1351	template<typename _Bi_iter, typename _Ch_traits, typename _Ch_alloc>
1352	inline bool
1353	operator<=(const sub_match<_Bi_iter>& __lhs,
1354	const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __rhs)
1355	{ return !(__rhs < __lhs); }
1356
1357	/**
1358	* @brief Tests the equivalence of a C string and a regular expression
1359	* submatch.
1360	* @param __lhs A null-terminated string.
1361	* @param __rhs A regular expression submatch.
1362	* @returns true if @a __lhs is equivalent to @a __rhs, false otherwise.
1363	*/
1364	template<typename _Bi_iter>
1365	inline bool
1366	operator==(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
1367	const sub_match<_Bi_iter>& __rhs)
1368	{ return __rhs.compare(__lhs) == `0`; }
1369
1370	/**
1371	* @brief Tests the inequivalence of a C string and a regular
1372	* expression submatch.
1373	* @param __lhs A null-terminated string.
1374	* @param __rhs A regular expression submatch.
1375	* @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
1376	*/
1377	template<typename _Bi_iter>
1378	inline bool
1379	operator!=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
1380	const sub_match<_Bi_iter>& __rhs)
1381	{ return !(__lhs == __rhs); }
1382
1383	/**
1384	* @brief Tests the ordering of a C string and a regular expression submatch.
1385	* @param __lhs A null-terminated string.
1386	* @param __rhs A regular expression submatch.
1387	* @returns true if @a __lhs precedes @a __rhs, false otherwise.
1388	*/
1389	template<typename _Bi_iter>
1390	inline bool
1391	operator<(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
1392	const sub_match<_Bi_iter>& __rhs)
1393	{ return __rhs.compare(__lhs) > `0`; }
1394
1395	/**
1396	* @brief Tests the ordering of a C string and a regular expression submatch.
1397	* @param __lhs A null-terminated string.
1398	* @param __rhs A regular expression submatch.
1399	* @returns true if @a __lhs succeeds @a __rhs, false otherwise.
1400	*/
1401	template<typename _Bi_iter>
1402	inline bool
1403	operator>(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
1404	const sub_match<_Bi_iter>& __rhs)
1405	{ return __rhs < __lhs; }
1406
1407	/**
1408	* @brief Tests the ordering of a C string and a regular expression submatch.
1409	* @param __lhs A null-terminated string.
1410	* @param __rhs A regular expression submatch.
1411	* @returns true if @a __lhs does not precede @a __rhs, false otherwise.
1412	*/
1413	template<typename _Bi_iter>
1414	inline bool
1415	operator>=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
1416	const sub_match<_Bi_iter>& __rhs)
1417	{ return !(__lhs < __rhs); }
1418
1419	/**
1420	* @brief Tests the ordering of a C string and a regular expression submatch.
1421	* @param __lhs A null-terminated string.
1422	* @param __rhs A regular expression submatch.
1423	* @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
1424	*/
1425	template<typename _Bi_iter>
1426	inline bool
1427	operator<=(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
1428	const sub_match<_Bi_iter>& __rhs)
1429	{ return !(__rhs < __lhs); }
1430	#endif // three-way comparison
1431
1432	/**
1433	* @brief Tests the equivalence of a regular expression submatch and a C
1434	* string.
1435	* @param __lhs A regular expression submatch.
1436	* @param __rhs A null-terminated string.
1437	* @returns true if @a __lhs is equivalent to @a __rhs, false otherwise.
1438	*/
1439	template<typename _Bi_iter>
1440	inline bool
1441	operator==(const sub_match<_Bi_iter>& __lhs,
1442	typename iterator_traits<_Bi_iter>::value_type const* __rhs)
1443	{ return __lhs.compare(__rhs) == `0`; }
1444
1445	#if __cpp_lib_three_way_comparison
1446	/**
1447	* @brief Three-way comparison of a regular expression submatch and a C
1448	* string.
1449	* @param __lhs A regular expression submatch.
1450	* @param __rhs A null-terminated string.
1451	* @returns A value indicating whether `__lhs` is less than, equal to,
1452	* greater than, or incomparable with `__rhs`.
1453	*/
1454	template<typename _Bi_iter>
1455	inline auto
1456	operator<=>(const sub_match<_Bi_iter>& __lhs,
1457	typename iterator_traits<_Bi_iter>::value_type const* __rhs)
1458	noexcept(__detail::__is_contiguous_iter<_Bi_iter>::value)
1459	{
1460	using _Tr = char_traits<typename iterator_traits<_Bi_iter>::value_type>;
1461	return __detail::__char_traits_cmp_cat<_Tr>(__lhs.compare(__rhs));
1462	}
1463	#else
1464	/**
1465	* @brief Tests the inequivalence of a regular expression submatch and a
1466	* string.
1467	* @param __lhs A regular expression submatch.
1468	* @param __rhs A null-terminated string.
1469	* @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
1470	*/
1471	template<typename _Bi_iter>
1472	inline bool
1473	operator!=(const sub_match<_Bi_iter>& __lhs,
1474	typename iterator_traits<_Bi_iter>::value_type const* __rhs)
1475	{ return !(__lhs == __rhs); }
1476
1477	/**
1478	* @brief Tests the ordering of a regular expression submatch and a C string.
1479	* @param __lhs A regular expression submatch.
1480	* @param __rhs A null-terminated string.
1481	* @returns true if @a __lhs precedes @a __rhs, false otherwise.
1482	*/
1483	template<typename _Bi_iter>
1484	inline bool
1485	operator<(const sub_match<_Bi_iter>& __lhs,
1486	typename iterator_traits<_Bi_iter>::value_type const* __rhs)
1487	{ return __lhs.compare(__rhs) < `0`; }
1488
1489	/**
1490	* @brief Tests the ordering of a regular expression submatch and a C string.
1491	* @param __lhs A regular expression submatch.
1492	* @param __rhs A null-terminated string.
1493	* @returns true if @a __lhs succeeds @a __rhs, false otherwise.
1494	*/
1495	template<typename _Bi_iter>
1496	inline bool
1497	operator>(const sub_match<_Bi_iter>& __lhs,
1498	typename iterator_traits<_Bi_iter>::value_type const* __rhs)
1499	{ return __rhs < __lhs; }
1500
1501	/**
1502	* @brief Tests the ordering of a regular expression submatch and a C string.
1503	* @param __lhs A regular expression submatch.
1504	* @param __rhs A null-terminated string.
1505	* @returns true if @a __lhs does not precede @a __rhs, false otherwise.
1506	*/
1507	template<typename _Bi_iter>
1508	inline bool
1509	operator>=(const sub_match<_Bi_iter>& __lhs,
1510	typename iterator_traits<_Bi_iter>::value_type const* __rhs)
1511	{ return !(__lhs < __rhs); }
1512
1513	/**
1514	* @brief Tests the ordering of a regular expression submatch and a C string.
1515	* @param __lhs A regular expression submatch.
1516	* @param __rhs A null-terminated string.
1517	* @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
1518	*/
1519	template<typename _Bi_iter>
1520	inline bool
1521	operator<=(const sub_match<_Bi_iter>& __lhs,
1522	typename iterator_traits<_Bi_iter>::value_type const* __rhs)
1523	{ return !(__rhs < __lhs); }
1524
1525	/**
1526	* @brief Tests the equivalence of a character and a regular expression
1527	* submatch.
1528	* @param __lhs A character.
1529	* @param __rhs A regular expression submatch.
1530	* @returns true if @a __lhs is equivalent to @a __rhs, false otherwise.
1531	*/
1532	template<typename _Bi_iter>
1533	inline bool
1534	operator==(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
1535	const sub_match<_Bi_iter>& __rhs)
1536	{ return __rhs._M_compare(std::__addressof(__lhs), `1`) == `0`; }
1537
1538	/**
1539	* @brief Tests the inequivalence of a character and a regular expression
1540	* submatch.
1541	* @param __lhs A character.
1542	* @param __rhs A regular expression submatch.
1543	* @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
1544	*/
1545	template<typename _Bi_iter>
1546	inline bool
1547	operator!=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
1548	const sub_match<_Bi_iter>& __rhs)
1549	{ return !(__lhs == __rhs); }
1550
1551	/**
1552	* @brief Tests the ordering of a character and a regular expression
1553	* submatch.
1554	* @param __lhs A character.
1555	* @param __rhs A regular expression submatch.
1556	* @returns true if @a __lhs precedes @a __rhs, false otherwise.
1557	*/
1558	template<typename _Bi_iter>
1559	inline bool
1560	operator<(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
1561	const sub_match<_Bi_iter>& __rhs)
1562	{ return __rhs._M_compare(std::__addressof(__lhs), `1`) > `0`; }
1563
1564	/**
1565	* @brief Tests the ordering of a character and a regular expression
1566	* submatch.
1567	* @param __lhs A character.
1568	* @param __rhs A regular expression submatch.
1569	* @returns true if @a __lhs succeeds @a __rhs, false otherwise.
1570	*/
1571	template<typename _Bi_iter>
1572	inline bool
1573	operator>(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
1574	const sub_match<_Bi_iter>& __rhs)
1575	{ return __rhs < __lhs; }
1576
1577	/**
1578	* @brief Tests the ordering of a character and a regular expression
1579	* submatch.
1580	* @param __lhs A character.
1581	* @param __rhs A regular expression submatch.
1582	* @returns true if @a __lhs does not precede @a __rhs, false otherwise.
1583	*/
1584	template<typename _Bi_iter>
1585	inline bool
1586	operator>=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
1587	const sub_match<_Bi_iter>& __rhs)
1588	{ return !(__lhs < __rhs); }
1589
1590	/**
1591	* @brief Tests the ordering of a character and a regular expression
1592	* submatch.
1593	* @param __lhs A character.
1594	* @param __rhs A regular expression submatch.
1595	* @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
1596	*/
1597	template<typename _Bi_iter>
1598	inline bool
1599	operator<=(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
1600	const sub_match<_Bi_iter>& __rhs)
1601	{ return !(__rhs < __lhs); }
1602	#endif // three-way comparison
1603
1604	/**
1605	* @brief Tests the equivalence of a regular expression submatch and a
1606	* character.
1607	* @param __lhs A regular expression submatch.
1608	* @param __rhs A character.
1609	* @returns true if @a __lhs is equivalent to @a __rhs, false otherwise.
1610	*/
1611	template<typename _Bi_iter>
1612	inline bool
1613	operator==(const sub_match<_Bi_iter>& __lhs,
1614	typename iterator_traits<_Bi_iter>::value_type const& __rhs)
1615	{ return __lhs._M_compare(std::__addressof(__rhs), `1`) == `0`; }
1616
1617	#if __cpp_lib_three_way_comparison
1618	/**
1619	* @brief Three-way comparison of a regular expression submatch and a
1620	* character.
1621	* @param __lhs A regular expression submatch.
1622	* @param __rhs A character.
1623	* @returns A value indicating whether `__lhs` is less than, equal to,
1624	* greater than, or incomparable with `__rhs`.
1625	*/
1626
1627	template<typename _Bi_iter>
1628	inline auto
1629	operator<=>(const sub_match<_Bi_iter>& __lhs,
1630	typename iterator_traits<_Bi_iter>::value_type const& __rhs)
1631	noexcept(__detail::__is_contiguous_iter<_Bi_iter>::value)
1632	{
1633	using _Tr = char_traits<typename iterator_traits<_Bi_iter>::value_type>;
1634	return __detail::__char_traits_cmp_cat<_Tr>(
1635	__lhs._M_compare(std::__addressof(__rhs), `1`));
1636	}
1637	#else
1638	/**
1639	* @brief Tests the inequivalence of a regular expression submatch and a
1640	* character.
1641	* @param __lhs A regular expression submatch.
1642	* @param __rhs A character.
1643	* @returns true if @a __lhs is not equivalent to @a __rhs, false otherwise.
1644	*/
1645	template<typename _Bi_iter>
1646	inline bool
1647	operator!=(const sub_match<_Bi_iter>& __lhs,
1648	typename iterator_traits<_Bi_iter>::value_type const& __rhs)
1649	{ return !(__lhs == __rhs); }
1650
1651	/**
1652	* @brief Tests the ordering of a regular expression submatch and a
1653	* character.
1654	* @param __lhs A regular expression submatch.
1655	* @param __rhs A character.
1656	* @returns true if @a __lhs precedes @a __rhs, false otherwise.
1657	*/
1658	template<typename _Bi_iter>
1659	inline bool
1660	operator<(const sub_match<_Bi_iter>& __lhs,
1661	typename iterator_traits<_Bi_iter>::value_type const& __rhs)
1662	{ return __lhs._M_compare(std::__addressof(__rhs), `1`) < `0`; }
1663
1664	/**
1665	* @brief Tests the ordering of a regular expression submatch and a
1666	* character.
1667	* @param __lhs A regular expression submatch.
1668	* @param __rhs A character.
1669	* @returns true if @a __lhs succeeds @a __rhs, false otherwise.
1670	*/
1671	template<typename _Bi_iter>
1672	inline bool
1673	operator>(const sub_match<_Bi_iter>& __lhs,
1674	typename iterator_traits<_Bi_iter>::value_type const& __rhs)
1675	{ return __rhs < __lhs; }
1676
1677	/**
1678	* @brief Tests the ordering of a regular expression submatch and a
1679	* character.
1680	* @param __lhs A regular expression submatch.
1681	* @param __rhs A character.
1682	* @returns true if @a __lhs does not precede @a __rhs, false otherwise.
1683	*/
1684	template<typename _Bi_iter>
1685	inline bool
1686	operator>=(const sub_match<_Bi_iter>& __lhs,
1687	typename iterator_traits<_Bi_iter>::value_type const& __rhs)
1688	{ return !(__lhs < __rhs); }
1689
1690	/**
1691	* @brief Tests the ordering of a regular expression submatch and a
1692	* character.
1693	* @param __lhs A regular expression submatch.
1694	* @param __rhs A character.
1695	* @returns true if @a __lhs does not succeed @a __rhs, false otherwise.
1696	*/
1697	template<typename _Bi_iter>
1698	inline bool
1699	operator<=(const sub_match<_Bi_iter>& __lhs,
1700	typename iterator_traits<_Bi_iter>::value_type const& __rhs)
1701	{ return !(__rhs < __lhs); }
1702	#endif // three-way comparison
1703
1704	/**
1705	* @brief Inserts a matched string into an output stream.
1706	*
1707	* @param __os The output stream.
1708	* @param __m A submatch string.
1709	*
1710	* @returns the output stream with the submatch string inserted.
1711	*/
1712	template<typename _Ch_type, typename _Ch_traits, typename _Bi_iter>
1713	inline
1714	basic_ostream<_Ch_type, _Ch_traits>&
1715	operator<<(basic_ostream<_Ch_type, _Ch_traits>& __os,
1716	const sub_match<_Bi_iter>& __m)
1717	{ return __os << __m.str(); }
1718
1719	/// @} relates sub_match
1720
1721	// [7.10] Class template match_results
1722
1723	/**
1724	* @brief The results of a match or search operation.
1725	*
1726	* A collection of character sequences representing the result of a regular
1727	* expression match. Storage for the collection is allocated and freed as
1728	* necessary by the member functions of class template match_results.
1729	*
1730	* This class satisfies the Sequence requirements, with the exception that
1731	* only the operations defined for a const-qualified Sequence are supported.
1732	*
1733	* The sub_match object stored at index 0 represents sub-expression 0, i.e.
1734	* the whole match. In this case the %sub_match member matched is always true.
1735	* The sub_match object stored at index n denotes what matched the marked
1736	* sub-expression n within the matched expression. If the sub-expression n
1737	* participated in a regular expression match then the %sub_match member
1738	* matched evaluates to true, and members first and second denote the range
1739	* of characters [first, second) which formed that match. Otherwise matched
1740	* is false, and members first and second point to the end of the sequence
1741	* that was searched.
1742	*
1743	* @headerfile regex
1744	* @since C++11
1745	*/
1746	template<typename _Bi_iter,
1747	typename _Alloc = allocator<sub_match<_Bi_iter> > >
1748	class match_results
1749	: private std::vector<sub_match<_Bi_iter>, _Alloc>
1750	{
1751	private:
1752	/*
1753	* The vector base is empty if this does not represent a match (!ready());
1754	* Otherwise if it's a match failure, it contains 3 elements:
1755	* [0] unmatched
1756	* [1] prefix
1757	* [2] suffix
1758	* Otherwise it contains n+4 elements where n is the number of marked
1759	* sub-expressions:
1760	* [0] entire match
1761	* [1] 1st marked subexpression
1762	* ...
1763	* [n] nth marked subexpression
1764	* [n+1] unmatched
1765	* [n+2] prefix
1766	* [n+3] suffix
1767	*/
1768	typedef std::vector<sub_match<_Bi_iter>, _Alloc> _Base_type;
1769	// In debug mode _Base_type is the debug vector, this is the unsafe one:
1770	typedef _GLIBCXX_STD_C::vector<sub_match<_Bi_iter>, _Alloc> _Unchecked;
1771	typedef std::iterator_traits<_Bi_iter> __iter_traits;
1772	typedef regex_constants::match_flag_type match_flag_type;
1773
1774	public:
1775	/**
1776	* @name 28.10 Public Types
1777	*/
1778	///@{
1779	typedef sub_match<_Bi_iter> value_type;
1780	typedef const value_type& const_reference;
1781	typedef value_type& reference;
1782	typedef typename _Base_type::const_iterator const_iterator;
1783	typedef const_iterator iterator;
1784	typedef typename __iter_traits::difference_type difference_type;
1785	typedef typename allocator_traits<_Alloc>::size_type size_type;
1786	typedef _Alloc allocator_type;
1787	typedef typename __iter_traits::value_type char_type;
1788	typedef std::basic_string<char_type> string_type;
1789	///@}
1790
1791	public:
1792	/**
1793	* @name 28.10.1 Construction, Copying, and Destruction
1794	*/
1795	///@{
1796
1797	/**
1798	* @brief Constructs a default %match_results container.
1799	* @post size() returns 0 and str() returns an empty string.
1800	*/
1801	match_results() : match_results(_Alloc()) { }
1802
1803	/**
1804	* @brief Constructs a default %match_results container.
1805	* @post size() returns 0 and str() returns an empty string.
1806	*/
1807	explicit
1808	match_results(const _Alloc& __a) noexcept
1809	: _Base_type(__a)
1810	{ }
1811
1812	/**
1813	* @brief Copy constructs a %match_results.
1814	*/
1815	match_results(const match_results&) = default;
1816
1817	/**
1818	* @brief Move constructs a %match_results.
1819	*/
1820	match_results(match_results&&) noexcept = default;
1821
1822	/**
1823	* @brief Assigns rhs to *this.
1824	*/
1825	match_results&
1826	operator=(const match_results&) = default;
1827
1828	/**
1829	* @brief Move-assigns rhs to *this.
1830	*/
1831	match_results&
1832	operator=(match_results&&) = default;
1833
1834	/**
1835	* @brief Destroys a %match_results object.
1836	*/
1837	~match_results() = default;
1838
1839	// _GLIBCXX_RESOLVE_LIB_DEFECTS
1840	// 2195. Missing constructors for match_results
1841
1842	match_results(const match_results& __m, const _Alloc& __a)
1843	: _Base_type(__m, __a) { }
1844
1845	match_results(match_results&& __m, const _Alloc& __a)
1846	noexcept(noexcept(_Base_type(std::move(__m), __a)))
1847	: _Base_type(std::move(__m), __a) { }
1848
1849	///@}
1850
1851	// 28.10.2, state:
1852	/**
1853	* @brief Indicates if the %match_results is ready.
1854	* @retval true The object has a fully-established result state.
1855	* @retval false The object is not ready.
1856	*/
1857	bool ready() const noexcept { return !_Unchecked::empty(); }
1858
1859	/**
1860	* @name 28.10.2 Size
1861	*/
1862	///@{
1863
1864	/**
1865	* @brief Gets the number of matches and submatches.
1866	*
1867	* The number of matches for a given regular expression will be either 0
1868	* if there was no match or mark_count() + 1 if a match was successful.
1869	* Some matches may be empty.
1870	*
1871	* @returns the number of matches found.
1872	*/
1873	size_type
1874	size() const noexcept
1875	{ return _Unchecked::empty() ? `0` : _Unchecked::size() - `3`; }
1876
1877	size_type
1878	max_size() const noexcept
1879	{ return _Unchecked::max_size() - `3`; }
1880
1881	/**
1882	* @brief Indicates if the %match_results contains no results.
1883	* @retval true The %match_results object is empty.
1884	* @retval false The %match_results object is not empty.
1885	*/
1886	_GLIBCXX_NODISCARD bool
1887	empty() const noexcept
1888	{ return _Unchecked::size() <= `3`; }
1889
1890	///@}
1891
1892	/**
1893	* @name 28.10.4 Element Access
1894	*/
1895	///@{
1896
1897	/**
1898	* @brief Gets the length of the indicated submatch.
1899	* @param __sub indicates the submatch.
1900	* @pre ready() == true
1901	*
1902	* This function returns the length of the indicated submatch, or the
1903	* length of the entire match if @p __sub is zero (the default).
1904	*/
1905	difference_type
1906	length(size_type __sub = `0`) const
1907	{ return (*this)[__sub].length(); }
1908
1909	/**
1910	* @brief Gets the offset of the beginning of the indicated submatch.
1911	* @param __sub indicates the submatch.
1912	* @pre ready() == true
1913	*
1914	* This function returns the offset from the beginning of the target
1915	* sequence to the beginning of the submatch, unless the value of @p __sub
1916	* is zero (the default), in which case this function returns the offset
1917	* from the beginning of the target sequence to the beginning of the
1918	* match.
1919	*/
1920	difference_type
1921	position(size_type __sub = `0`) const
1922	{ return std::distance(_M_begin, (*this)[__sub].first); }
1923
1924	/**
1925	* @brief Gets the match or submatch converted to a string type.
1926	* @param __sub indicates the submatch.
1927	* @pre ready() == true
1928	*
1929	* This function gets the submatch (or match, if @p __sub is
1930	* zero) extracted from the target range and converted to the
1931	* associated string type.
1932	*/
1933	string_type
1934	str(size_type __sub = `0`) const
1935	{ return string_type((*this)[__sub]); }
1936
1937	/**
1938	* @brief Gets a %sub_match reference for the match or submatch.
1939	* @param __sub indicates the submatch.
1940	* @pre ready() == true
1941	*
1942	* This function gets a reference to the indicated submatch, or
1943	* the entire match if @p __sub is zero.
1944	*
1945	* If @p __sub >= size() then this function returns a %sub_match with a
1946	* special value indicating no submatch.
1947	*/
1948	const_reference
1949	operator[](size_type __sub) const
1950	{
1951	__glibcxx_assert( ready() );
1952	return __sub < size()
1953	? _Unchecked::operator[](__sub)
1954	: _M_unmatched_sub();
1955	}
1956
1957	/**
1958	* @brief Gets a %sub_match representing the match prefix.
1959	* @pre ready() == true
1960	*
1961	* This function gets a reference to a %sub_match object representing the
1962	* part of the target range between the start of the target range and the
1963	* start of the match.
1964	*/
1965	const_reference
1966	prefix() const
1967	{
1968	__glibcxx_assert( ready() );
1969	return !empty() ? _M_prefix() : _M_unmatched_sub();
1970	}
1971
1972	/**
1973	* @brief Gets a %sub_match representing the match suffix.
1974	* @pre ready() == true
1975	*
1976	* This function gets a reference to a %sub_match object representing the
1977	* part of the target range between the end of the match and the end of
1978	* the target range.
1979	*/
1980	const_reference
1981	suffix() const
1982	{
1983	__glibcxx_assert( ready() );
1984	return !empty() ? _M_suffix() : _M_unmatched_sub();
1985	}
1986
1987	/**
1988	* @brief Gets an iterator to the start of the %sub_match collection.
1989	*/
1990	const_iterator
1991	begin() const noexcept
1992	{ return _Base_type::begin(); }
1993
1994	/**
1995	* @brief Gets an iterator to the start of the %sub_match collection.
1996	*/
1997	const_iterator
1998	cbegin() const noexcept
1999	{ return this->begin(); }
2000
2001	/**
2002	* @brief Gets an iterator to one-past-the-end of the collection.
2003	*/
2004	const_iterator
2005	end() const noexcept
2006	{ return _Base_type::end() - (_Base_type::empty() ? `0` : `3`); }
2007
2008	/**
2009	* @brief Gets an iterator to one-past-the-end of the collection.
2010	*/
2011	const_iterator
2012	cend() const noexcept
2013	{ return this->end(); }
2014
2015	///@}
2016
2017	/**
2018	* @name 28.10.5 Formatting
2019	*
2020	* These functions perform formatted substitution of the matched
2021	* character sequences into their target. The format specifiers and
2022	* escape sequences accepted by these functions are determined by
2023	* their @p flags parameter as documented above.
2024	*/
2025	///@{
2026
2027	/**
2028	* @pre ready() == true
2029	*/
2030	template<typename _Out_iter>
2031	_Out_iter
2032	format(_Out_iter __out, const char_type* __fmt_first,
2033	const char_type* __fmt_last,
2034	match_flag_type __flags = regex_constants::format_default) const;
2035
2036	/**
2037	* @pre ready() == true
2038	*/
2039	template<typename _Out_iter, typename _St, typename _Sa>
2040	_Out_iter
2041	format(_Out_iter __out, const basic_string<char_type, _St, _Sa>& __fmt,
2042	match_flag_type __flags = regex_constants::format_default) const
2043	{
2044	return format(__out, __fmt.data(), __fmt.data() + __fmt.size(),
2045	__flags);
2046	}
2047
2048	/**
2049	* @pre ready() == true
2050	*/
2051	template<typename _St, typename _Sa>
2052	basic_string<char_type, _St, _Sa>
2053	format(const basic_string<char_type, _St, _Sa>& __fmt,
2054	match_flag_type __flags = regex_constants::format_default) const
2055	{
2056	basic_string<char_type, _St, _Sa> __result;
2057	format(std::back_inserter(__result), __fmt, __flags);
2058	return __result;
2059	}
2060
2061	/**
2062	* @pre ready() == true
2063	*/
2064	string_type
2065	format(const char_type* __fmt,
2066	match_flag_type __flags = regex_constants::format_default) const
2067	{
2068	string_type __result;
2069	format(std::back_inserter(__result),
2070	__fmt,
2071	__fmt + char_traits<char_type>::length(__fmt),
2072	__flags);
2073	return __result;
2074	}
2075
2076	///@}
2077
2078	/**
2079	* @name 28.10.6 Allocator
2080	*/
2081	///@{
2082
2083	/**
2084	* @brief Gets a copy of the allocator.
2085	*/
2086	allocator_type
2087	get_allocator() const noexcept
2088	{ return _Base_type::get_allocator(); }
2089
2090	///@}
2091
2092	/**
2093	* @name 28.10.7 Swap
2094	*/
2095	///@{
2096
2097	/**
2098	* @brief Swaps the contents of two match_results.
2099	*/
2100	void
2101	swap(match_results& __that) noexcept
2102	{
2103	using std::swap;
2104	_Base_type::swap(__that);
2105	swap(_M_begin, __that._M_begin);
2106	}
2107	///@}
2108
2109	private:
2110	template<typename, typename, typename>
2111	friend class regex_iterator;
2112
2113	/// @cond undocumented
2114
2115	template<typename, typename, typename, bool>
2116	friend class __detail::_Executor;
2117
2118	template<typename _Bp, typename _Ap, typename _Cp, typename _Rp>
2119	friend bool
2120	__detail::__regex_algo_impl(_Bp, _Bp, match_results<_Bp, _Ap>&,
2121	const basic_regex<_Cp, _Rp>&,
2122	regex_constants::match_flag_type,
2123	__detail::_RegexExecutorPolicy, bool);
2124
2125	// Reset contents to __size unmatched sub_match objects
2126	// (plus additional objects for prefix, suffix and unmatched sub).
2127	void
2128	_M_resize(unsigned int __size)
2129	{ _Unchecked::assign(__size + `3`, sub_match<_Bi_iter>{}); }
2130
2131	// Set state to a failed match for the given past-the-end iterator.
2132	void
2133	_M_establish_failed_match(_Bi_iter __end)
2134	{
2135	sub_match<_Bi_iter> __sm;
2136	__sm.first = __sm.second = __end;
2137	_Unchecked::assign(`3`, __sm);
2138	}
2139
2140	const_reference
2141	_M_unmatched_sub() const
2142	{ return _Unchecked::operator[](_Unchecked::size() - `3`); }
2143
2144	sub_match<_Bi_iter>&
2145	_M_unmatched_sub()
2146	{ return _Unchecked::operator[](_Unchecked::size() - `3`); }
2147
2148	const_reference
2149	_M_prefix() const
2150	{ return _Unchecked::operator[](_Unchecked::size() - `2`); }
2151
2152	sub_match<_Bi_iter>&
2153	_M_prefix()
2154	{ return _Unchecked::operator[](_Unchecked::size() - `2`); }
2155
2156	const_reference
2157	_M_suffix() const
2158	{ return _Unchecked::operator[](_Unchecked::size() - `1`); }
2159
2160	sub_match<_Bi_iter>&
2161	_M_suffix()
2162	{ return _Unchecked::operator[](_Unchecked::size() - `1`); }
2163
2164	_Bi_iter _M_begin {};
2165	/// @endcond
2166	};
2167
2168	typedef match_results<const char*> cmatch;
2169	typedef match_results<string::const_iterator> smatch;
2170	#ifdef _GLIBCXX_USE_WCHAR_T
2171	typedef match_results<const wchar_t*> wcmatch;
2172	typedef match_results<wstring::const_iterator> wsmatch;
2173	#endif
2174
2175	// match_results comparisons
2176
2177	/**
2178	* @brief Compares two match_results for equality.
2179	* @returns true if the two objects refer to the same match,
2180	* false otherwise.
2181	*
2182	* @relates match_results
2183	*/
2184	template<typename _Bi_iter, typename _Alloc>
2185	inline bool
2186	operator==(const match_results<_Bi_iter, _Alloc>& __m1,
2187	const match_results<_Bi_iter, _Alloc>& __m2)
2188	{
2189	if (__m1.ready() != __m2.ready())
2190	return false;
2191	if (!__m1.ready()) // both are not ready
2192	return true;
2193	if (__m1.empty() != __m2.empty())
2194	return false;
2195	if (__m1.empty()) // both are empty
2196	return true;
2197	return __m1.prefix() == __m2.prefix()
2198	&& __m1.size() == __m2.size()
2199	&& std::equal(__m1.begin(), __m1.end(), __m2.begin())
2200	&& __m1.suffix() == __m2.suffix();
2201	}
2202
2203	#if ! __cpp_lib_three_way_comparison
2204	/**
2205	* @brief Compares two match_results for inequality.
2206	* @returns true if the two objects do not refer to the same match,
2207	* false otherwise.
2208	*
2209	* @relates match_results
2210	*/
2211	template<typename _Bi_iter, class _Alloc>
2212	inline bool
2213	operator!=(const match_results<_Bi_iter, _Alloc>& __m1,
2214	const match_results<_Bi_iter, _Alloc>& __m2)
2215	{ return !(__m1 == __m2); }
2216	#endif
2217
2218	// [7.10.6] match_results swap
2219	/**
2220	* @brief Swaps two match results.
2221	* @param __lhs A match result.
2222	* @param __rhs A match result.
2223	*
2224	* The contents of the two match_results objects are swapped.
2225	*
2226	* @relates match_results
2227	*/
2228	template<typename _Bi_iter, typename _Alloc>
2229	inline void
2230	swap(match_results<_Bi_iter, _Alloc>& __lhs,
2231	match_results<_Bi_iter, _Alloc>& __rhs) noexcept
2232	{ __lhs.swap(__rhs); }
2233
2234	_GLIBCXX_END_NAMESPACE_CXX11
2235
2236	// [28.11.2] Function template regex_match
2237	/**
2238	* @name Matching, Searching, and Replacing
2239	*
2240	* @{
2241	*/
2242
2243	/**
2244	* @brief Determines if there is a match between the regular expression @p e
2245	* and all of the character sequence [first, last).
2246	*
2247	* @param __s Start of the character sequence to match.
2248	* @param __e One-past-the-end of the character sequence to match.
2249	* @param __m The match results.
2250	* @param __re The regular expression.
2251	* @param __flags Controls how the regular expression is matched.
2252	*
2253	* @retval true A match exists.
2254	* @retval false Otherwise.
2255	*
2256	* @throws an exception of type regex_error.
2257	*/
2258	template<typename _Bi_iter, typename _Alloc,
2259	typename _Ch_type, typename _Rx_traits>
2260	inline bool
2261	regex_match(_Bi_iter __s,
2262	_Bi_iter __e,
2263	match_results<_Bi_iter, _Alloc>& __m,
2264	const basic_regex<_Ch_type, _Rx_traits>& __re,
2265	regex_constants::match_flag_type __flags
2266	= regex_constants::match_default)
2267	{
2268	return __detail::__regex_algo_impl(__s, __e, __m, __re, __flags,
2269	__detail::_RegexExecutorPolicy::_S_auto, true);
2270	}
2271
2272	/**
2273	* @brief Indicates if there is a match between the regular expression @p e
2274	* and all of the character sequence [first, last).
2275	*
2276	* @param __first Beginning of the character sequence to match.
2277	* @param __last One-past-the-end of the character sequence to match.
2278	* @param __re The regular expression.
2279	* @param __flags Controls how the regular expression is matched.
2280	*
2281	* @retval true A match exists.
2282	* @retval false Otherwise.
2283	*
2284	* @throws an exception of type regex_error.
2285	*/
2286	template<typename _Bi_iter, typename _Ch_type, typename _Rx_traits>
2287	inline bool
2288	regex_match(_Bi_iter __first, _Bi_iter __last,
2289	const basic_regex<_Ch_type, _Rx_traits>& __re,
2290	regex_constants::match_flag_type __flags
2291	= regex_constants::match_default)
2292	{
2293	match_results<_Bi_iter> __what;
2294	return regex_match(__first, __last, __what, __re, __flags);
2295	}
2296
2297	/**
2298	* @brief Determines if there is a match between the regular expression @p e
2299	* and a C-style null-terminated string.
2300	*
2301	* @param __s The C-style null-terminated string to match.
2302	* @param __m The match results.
2303	* @param __re The regular expression.
2304	* @param __f Controls how the regular expression is matched.
2305	*
2306	* @retval true A match exists.
2307	* @retval false Otherwise.
2308	*
2309	* @throws an exception of type regex_error.
2310	*/
2311	template<typename _Ch_type, typename _Alloc, typename _Rx_traits>
2312	inline bool
2313	regex_match(const _Ch_type* __s,
2314	match_results<const _Ch_type*, _Alloc>& __m,
2315	const basic_regex<_Ch_type, _Rx_traits>& __re,
2316	regex_constants::match_flag_type __f
2317	= regex_constants::match_default)
2318	{ return regex_match(__s, __s + _Rx_traits::length(__s), __m, __re, __f); }
2319
2320	/**
2321	* @brief Determines if there is a match between the regular expression @p e
2322	* and a string.
2323	*
2324	* @param __s The string to match.
2325	* @param __m The match results.
2326	* @param __re The regular expression.
2327	* @param __flags Controls how the regular expression is matched.
2328	*
2329	* @retval true A match exists.
2330	* @retval false Otherwise.
2331	*
2332	* @throws an exception of type regex_error.
2333	*/
2334	template<typename _Ch_traits, typename _Ch_alloc,
2335	typename _Alloc, typename _Ch_type, typename _Rx_traits>
2336	inline bool
2337	regex_match(const basic_string<_Ch_type, _Ch_traits, _Ch_alloc>& __s,
2338	match_results<typename basic_string<_Ch_type,
2339	_Ch_traits, _Ch_alloc>::const_iterator, _Alloc>& __m,
2340	const basic_regex<_Ch_type, _Rx_traits>& __re,
2341	regex_constants::match_flag_type __flags
2342	= regex_constants::match_default)
2343	{ return regex_match(__s.begin(), __s.end(), __m, __re, __flags); }
2344
2345	// _GLIBCXX_RESOLVE_LIB_DEFECTS
2346	// 2329. regex_match() with match_results should forbid temporary strings
2347	/// Prevent unsafe attempts to get match_results from a temporary string.
2348	template<typename _Ch_traits, typename _Ch_alloc,
2349	typename _Alloc, typename _Ch_type, typename _Rx_traits>
2350	bool
2351	regex_match(const basic_string<_Ch_type, _Ch_traits, _Ch_alloc>&&,
2352	match_results<typename basic_string<_Ch_type,
2353	_Ch_traits, _Ch_alloc>::const_iterator, _Alloc>&,
2354	const basic_regex<_Ch_type, _Rx_traits>&,
2355	regex_constants::match_flag_type
2356	= regex_constants::match_default) = delete;
2357
2358	/**
2359	* @brief Indicates if there is a match between the regular expression @p e
2360	* and a C-style null-terminated string.
2361	*
2362	* @param __s The C-style null-terminated string to match.
2363	* @param __re The regular expression.
2364	* @param __f Controls how the regular expression is matched.
2365	*
2366	* @retval true A match exists.
2367	* @retval false Otherwise.
2368	*
2369	* @throws an exception of type regex_error.
2370	*/
2371	template<typename _Ch_type, class _Rx_traits>
2372	inline bool
2373	regex_match(const _Ch_type* __s,
2374	const basic_regex<_Ch_type, _Rx_traits>& __re,
2375	regex_constants::match_flag_type __f
2376	= regex_constants::match_default)
2377	{ return regex_match(__s, __s + _Rx_traits::length(__s), __re, __f); }
2378
2379	/**
2380	* @brief Indicates if there is a match between the regular expression @p e
2381	* and a string.
2382	*
2383	* @param __s [IN] The string to match.
2384	* @param __re [IN] The regular expression.
2385	* @param __flags [IN] Controls how the regular expression is matched.
2386	*
2387	* @retval true A match exists.
2388	* @retval false Otherwise.
2389	*
2390	* @throws an exception of type regex_error.
2391	*/
2392	template<typename _Ch_traits, typename _Str_allocator,
2393	typename _Ch_type, typename _Rx_traits>
2394	inline bool
2395	regex_match(const basic_string<_Ch_type, _Ch_traits, _Str_allocator>& __s,
2396	const basic_regex<_Ch_type, _Rx_traits>& __re,
2397	regex_constants::match_flag_type __flags
2398	= regex_constants::match_default)
2399	{ return regex_match(__s.begin(), __s.end(), __re, __flags); }
2400
2401	// [7.11.3] Function template regex_search
2402	/**
2403	* Searches for a regular expression within a range.
2404	* @param __s [IN] The start of the string to search.
2405	* @param __e [IN] One-past-the-end of the string to search.
2406	* @param __m [OUT] The match results.
2407	* @param __re [IN] The regular expression to search for.
2408	* @param __flags [IN] Search policy flags.
2409	* @retval true A match was found within the string.
2410	* @retval false No match was found within the string, the content of %m is
2411	* undefined.
2412	*
2413	* @throws an exception of type regex_error.
2414	*/
2415	template<typename _Bi_iter, typename _Alloc,
2416	typename _Ch_type, typename _Rx_traits>
2417	inline bool
2418	regex_search(_Bi_iter __s, _Bi_iter __e,
2419	match_results<_Bi_iter, _Alloc>& __m,
2420	const basic_regex<_Ch_type, _Rx_traits>& __re,
2421	regex_constants::match_flag_type __flags
2422	= regex_constants::match_default)
2423	{
2424	return __detail::__regex_algo_impl(__s, __e, __m, __re, __flags,
2425	__detail::_RegexExecutorPolicy::_S_auto, false);
2426	}
2427
2428	/**
2429	* Searches for a regular expression within a range.
2430	* @param __first [IN] The start of the string to search.
2431	* @param __last [IN] One-past-the-end of the string to search.
2432	* @param __re [IN] The regular expression to search for.
2433	* @param __flags [IN] Search policy flags.
2434	* @retval true A match was found within the string.
2435	* @retval false No match was found within the string.
2436	*
2437	* @throws an exception of type regex_error.
2438	*/
2439	template<typename _Bi_iter, typename _Ch_type, typename _Rx_traits>
2440	inline bool
2441	regex_search(_Bi_iter __first, _Bi_iter __last,
2442	const basic_regex<_Ch_type, _Rx_traits>& __re,
2443	regex_constants::match_flag_type __flags
2444	= regex_constants::match_default)
2445	{
2446	match_results<_Bi_iter> __what;
2447	return regex_search(__first, __last, __what, __re, __flags);
2448	}
2449
2450	/**
2451	* @brief Searches for a regular expression within a C-string.
2452	* @param __s [IN] A C-string to search for the regex.
2453	* @param __m [OUT] The set of regex matches.
2454	* @param __e [IN] The regex to search for in @p s.
2455	* @param __f [IN] The search flags.
2456	* @retval true A match was found within the string.
2457	* @retval false No match was found within the string, the content of %m is
2458	* undefined.
2459	*
2460	* @throws an exception of type regex_error.
2461	*/
2462	template<typename _Ch_type, class _Alloc, class _Rx_traits>
2463	inline bool
2464	regex_search(const _Ch_type* __s,
2465	match_results<const _Ch_type*, _Alloc>& __m,
2466	const basic_regex<_Ch_type, _Rx_traits>& __e,
2467	regex_constants::match_flag_type __f
2468	= regex_constants::match_default)
2469	{ return regex_search(__s, __s + _Rx_traits::length(__s), __m, __e, __f); }
2470
2471	/**
2472	* @brief Searches for a regular expression within a C-string.
2473	* @param __s [IN] The C-string to search.
2474	* @param __e [IN] The regular expression to search for.
2475	* @param __f [IN] Search policy flags.
2476	* @retval true A match was found within the string.
2477	* @retval false No match was found within the string.
2478	*
2479	* @throws an exception of type regex_error.
2480	*/
2481	template<typename _Ch_type, typename _Rx_traits>
2482	inline bool
2483	regex_search(const _Ch_type* __s,
2484	const basic_regex<_Ch_type, _Rx_traits>& __e,
2485	regex_constants::match_flag_type __f
2486	= regex_constants::match_default)
2487	{ return regex_search(__s, __s + _Rx_traits::length(__s), __e, __f); }
2488
2489	/**
2490	* @brief Searches for a regular expression within a string.
2491	* @param __s [IN] The string to search.
2492	* @param __e [IN] The regular expression to search for.
2493	* @param __flags [IN] Search policy flags.
2494	* @retval true A match was found within the string.
2495	* @retval false No match was found within the string.
2496	*
2497	* @throws an exception of type regex_error.
2498	*/
2499	template<typename _Ch_traits, typename _String_allocator,
2500	typename _Ch_type, typename _Rx_traits>
2501	inline bool
2502	regex_search(const basic_string<_Ch_type, _Ch_traits,
2503	_String_allocator>& __s,
2504	const basic_regex<_Ch_type, _Rx_traits>& __e,
2505	regex_constants::match_flag_type __flags
2506	= regex_constants::match_default)
2507	{ return regex_search(__s.begin(), __s.end(), __e, __flags); }
2508
2509	/**
2510	* @brief Searches for a regular expression within a string.
2511	* @param __s [IN] A C++ string to search for the regex.
2512	* @param __m [OUT] The set of regex matches.
2513	* @param __e [IN] The regex to search for in @p s.
2514	* @param __f [IN] The search flags.
2515	* @retval true A match was found within the string.
2516	* @retval false No match was found within the string, the content of %m is
2517	* undefined.
2518	*
2519	* @throws an exception of type regex_error.
2520	*/
2521	template<typename _Ch_traits, typename _Ch_alloc,
2522	typename _Alloc, typename _Ch_type,
2523	typename _Rx_traits>
2524	inline bool
2525	regex_search(const basic_string<_Ch_type, _Ch_traits, _Ch_alloc>& __s,
2526	match_results<typename basic_string<_Ch_type,
2527	_Ch_traits, _Ch_alloc>::const_iterator, _Alloc>& __m,
2528	const basic_regex<_Ch_type, _Rx_traits>& __e,
2529	regex_constants::match_flag_type __f
2530	= regex_constants::match_default)
2531	{ return regex_search(__s.begin(), __s.end(), __m, __e, __f); }
2532
2533	// _GLIBCXX_RESOLVE_LIB_DEFECTS
2534	// 2329. regex_search() with match_results should forbid temporary strings
2535	/// Prevent unsafe attempts to get match_results from a temporary string.
2536	template<typename _Ch_traits, typename _Ch_alloc,
2537	typename _Alloc, typename _Ch_type,
2538	typename _Rx_traits>
2539	bool
2540	regex_search(const basic_string<_Ch_type, _Ch_traits, _Ch_alloc>&&,
2541	match_results<typename basic_string<_Ch_type,
2542	_Ch_traits, _Ch_alloc>::const_iterator, _Alloc>&,
2543	const basic_regex<_Ch_type, _Rx_traits>&,
2544	regex_constants::match_flag_type
2545	= regex_constants::match_default) = delete;
2546
2547	// std [28.11.4] Function template regex_replace
2548
2549	/// @cond undocumented
2550	template<typename _Out_iter, typename _Bi_iter,
2551	typename _Rx_traits, typename _Ch_type>
2552	_Out_iter
2553	__regex_replace(_Out_iter __out, _Bi_iter __first, _Bi_iter __last,
2554	const basic_regex<_Ch_type, _Rx_traits>& __e,
2555	const _Ch_type* __fmt, size_t __len,
2556	regex_constants::match_flag_type __flags);
2557	/// @endcond
2558
2559	/**
2560	* @brief Search for a regular expression within a range for multiple times,
2561	and replace the matched parts through filling a format string.
2562	* @param __out [OUT] The output iterator.
2563	* @param __first [IN] The start of the string to search.
2564	* @param __last [IN] One-past-the-end of the string to search.
2565	* @param __e [IN] The regular expression to search for.
2566	* @param __fmt [IN] The format string.
2567	* @param __flags [IN] Search and replace policy flags.
2568	*
2569	* @returns __out
2570	* @throws an exception of type regex_error.
2571	*/
2572	template<typename _Out_iter, typename _Bi_iter,
2573	typename _Rx_traits, typename _Ch_type,
2574	typename _St, typename _Sa>
2575	inline _Out_iter
2576	regex_replace(_Out_iter __out, _Bi_iter __first, _Bi_iter __last,
2577	const basic_regex<_Ch_type, _Rx_traits>& __e,
2578	const basic_string<_Ch_type, _St, _Sa>& __fmt,
2579	regex_constants::match_flag_type __flags
2580	= regex_constants::match_default)
2581	{
2582	return std::__regex_replace(__out, __first, __last, __e, __fmt.c_str(),
2583	__fmt.length(), __flags);
2584	}
2585
2586	/**
2587	* @brief Search for a regular expression within a range for multiple times,
2588	and replace the matched parts through filling a format C-string.
2589	* @param __out [OUT] The output iterator.
2590	* @param __first [IN] The start of the string to search.
2591	* @param __last [IN] One-past-the-end of the string to search.
2592	* @param __e [IN] The regular expression to search for.
2593	* @param __fmt [IN] The format C-string.
2594	* @param __flags [IN] Search and replace policy flags.
2595	*
2596	* @returns __out
2597	* @throws an exception of type regex_error.
2598	*/
2599	template<typename _Out_iter, typename _Bi_iter,
2600	typename _Rx_traits, typename _Ch_type>
2601	_Out_iter
2602	regex_replace(_Out_iter __out, _Bi_iter __first, _Bi_iter __last,
2603	const basic_regex<_Ch_type, _Rx_traits>& __e,
2604	const _Ch_type* __fmt,
2605	regex_constants::match_flag_type __flags
2606	= regex_constants::match_default)
2607	{
2608	return std::__regex_replace(__out, __first, __last, __e, __fmt,
2609	char_traits<_Ch_type>::length(__fmt),
2610	__flags);
2611	}
2612
2613
2614	/**
2615	* @brief Search for a regular expression within a string for multiple times,
2616	and replace the matched parts through filling a format string.
2617	* @param __s [IN] The string to search and replace.
2618	* @param __e [IN] The regular expression to search for.
2619	* @param __fmt [IN] The format string.
2620	* @param __flags [IN] Search and replace policy flags.
2621	*
2622	* @returns The string after replacing.
2623	* @throws an exception of type regex_error.
2624	*/
2625	template<typename _Rx_traits, typename _Ch_type,
2626	typename _St, typename _Sa, typename _Fst, typename _Fsa>
2627	inline basic_string<_Ch_type, _St, _Sa>
2628	regex_replace(const basic_string<_Ch_type, _St, _Sa>& __s,
2629	const basic_regex<_Ch_type, _Rx_traits>& __e,
2630	const basic_string<_Ch_type, _Fst, _Fsa>& __fmt,
2631	regex_constants::match_flag_type __flags
2632	= regex_constants::match_default)
2633	{
2634	basic_string<_Ch_type, _St, _Sa> __result;
2635	regex_replace(std::back_inserter(__result),
2636	__s.begin(), __s.end(), __e, __fmt, __flags);
2637	return __result;
2638	}
2639
2640	/**
2641	* @brief Search for a regular expression within a string for multiple times,
2642	and replace the matched parts through filling a format C-string.
2643	* @param __s [IN] The string to search and replace.
2644	* @param __e [IN] The regular expression to search for.
2645	* @param __fmt [IN] The format C-string.
2646	* @param __flags [IN] Search and replace policy flags.
2647	*
2648	* @returns The string after replacing.
2649	* @throws an exception of type regex_error.
2650	*/
2651	template<typename _Rx_traits, typename _Ch_type,
2652	typename _St, typename _Sa>
2653	inline basic_string<_Ch_type, _St, _Sa>
2654	regex_replace(const basic_string<_Ch_type, _St, _Sa>& __s,
2655	const basic_regex<_Ch_type, _Rx_traits>& __e,
2656	const _Ch_type* __fmt,
2657	regex_constants::match_flag_type __flags
2658	= regex_constants::match_default)
2659	{
2660	basic_string<_Ch_type, _St, _Sa> __result;
2661	regex_replace(std::back_inserter(__result),
2662	__s.begin(), __s.end(), __e, __fmt, __flags);
2663	return __result;
2664	}
2665
2666	/**
2667	* @brief Search for a regular expression within a C-string for multiple
2668	times, and replace the matched parts through filling a format string.
2669	* @param __s [IN] The C-string to search and replace.
2670	* @param __e [IN] The regular expression to search for.
2671	* @param __fmt [IN] The format string.
2672	* @param __flags [IN] Search and replace policy flags.
2673	*
2674	* @returns The string after replacing.
2675	* @throws an exception of type regex_error.
2676	*/
2677	template<typename _Rx_traits, typename _Ch_type,
2678	typename _St, typename _Sa>
2679	inline basic_string<_Ch_type>
2680	regex_replace(const _Ch_type* __s,
2681	const basic_regex<_Ch_type, _Rx_traits>& __e,
2682	const basic_string<_Ch_type, _St, _Sa>& __fmt,
2683	regex_constants::match_flag_type __flags
2684	= regex_constants::match_default)
2685	{
2686	basic_string<_Ch_type> __result;
2687	regex_replace(std::back_inserter(__result), __s,
2688	__s + char_traits<_Ch_type>::length(__s),
2689	__e, __fmt, __flags);
2690	return __result;
2691	}
2692
2693	/**
2694	* @brief Search for a regular expression within a C-string for multiple
2695	times, and replace the matched parts through filling a format C-string.
2696	* @param __s [IN] The C-string to search and replace.
2697	* @param __e [IN] The regular expression to search for.
2698	* @param __fmt [IN] The format C-string.
2699	* @param __flags [IN] Search and replace policy flags.
2700	*
2701	* @returns The string after replacing.
2702	* @throws an exception of type regex_error.
2703	*/
2704	template<typename _Rx_traits, typename _Ch_type>
2705	inline basic_string<_Ch_type>
2706	regex_replace(const _Ch_type* __s,
2707	const basic_regex<_Ch_type, _Rx_traits>& __e,
2708	const _Ch_type* __fmt,
2709	regex_constants::match_flag_type __flags
2710	= regex_constants::match_default)
2711	{
2712	basic_string<_Ch_type> __result;
2713	regex_replace(std::back_inserter(__result), __s,
2714	__s + char_traits<_Ch_type>::length(__s),
2715	__e, __fmt, __flags);
2716	return __result;
2717	}
2718
2719	/// @}
2720
2721	_GLIBCXX_BEGIN_NAMESPACE_CXX11
2722
2723	// std [28.12] Class template regex_iterator
2724	/**
2725	* An iterator adaptor that will provide repeated calls of regex_search over
2726	* a range until no more matches remain.
2727	*
2728	* @headerfile regex
2729	* @since C++11
2730	*/
2731	template<typename _Bi_iter,
2732	typename _Ch_type = typename iterator_traits<_Bi_iter>::value_type,
2733	typename _Rx_traits = regex_traits<_Ch_type> >
2734	class regex_iterator
2735	{
2736	public:
2737	typedef basic_regex<_Ch_type, _Rx_traits> regex_type;
2738	typedef match_results<_Bi_iter> value_type;
2739	typedef std::ptrdiff_t difference_type;
2740	typedef const value_type* pointer;
2741	typedef const value_type& reference;
2742	typedef std::forward_iterator_tag iterator_category;
2743	#if __cplusplus > 201703L
2744	typedef std::input_iterator_tag iterator_concept;
2745	#endif
2746
2747	/**
2748	* @brief Provides a singular iterator, useful for indicating
2749	* one-past-the-end of a range.
2750	*/
2751	regex_iterator() = default;
2752
2753	/**
2754	* Constructs a %regex_iterator...
2755	* @param __a [IN] The start of a text range to search.
2756	* @param __b [IN] One-past-the-end of the text range to search.
2757	* @param __re [IN] The regular expression to match.
2758	* @param __m [IN] Policy flags for match rules.
2759	*/
2760	regex_iterator(_Bi_iter __a, _Bi_iter __b, const regex_type& __re,
2761	regex_constants::match_flag_type __m
2762	= regex_constants::match_default)
2763	: _M_begin(__a), _M_end(__b), _M_pregex(&__re), _M_flags(__m), _M_match()
2764	{
2765	if (!regex_search(_M_begin, _M_end, _M_match, *_M_pregex, _M_flags))
2766	*this = regex_iterator();
2767	}
2768
2769	// _GLIBCXX_RESOLVE_LIB_DEFECTS
2770	// 2332. regex_iterator should forbid temporary regexes
2771	regex_iterator(_Bi_iter, _Bi_iter, const regex_type&&,
2772	regex_constants::match_flag_type
2773	= regex_constants::match_default) = delete;
2774
2775	/// Copy constructs a %regex_iterator.
2776	regex_iterator(const regex_iterator&) = default;
2777
2778	/// Copy assigns one %regex_iterator to another.
2779	regex_iterator&
2780	operator=(const regex_iterator&) = default;
2781
2782	~regex_iterator() = default;
2783
2784	/**
2785	* @brief Tests the equivalence of two regex iterators.
2786	*/
2787	bool
2788	operator==(const regex_iterator&) const noexcept;
2789
2790	#if __cplusplus >= 202002L
2791	// _GLIBCXX_RESOLVE_LIB_DEFECTS
2792	// 3719. Directory iterators should be usable with default sentinel
2793	bool operator==(default_sentinel_t) const noexcept
2794	{ return _M_pregex == nullptr; }
2795	#endif
2796
2797	#if __cpp_impl_three_way_comparison < 201907L
2798	/**
2799	* @brief Tests the inequivalence of two regex iterators.
2800	*/
2801	bool
2802	operator!=(const regex_iterator& __rhs) const noexcept
2803	{ return !(*this == __rhs); }
2804	#endif
2805
2806	/**
2807	* @brief Dereferences a %regex_iterator.
2808	*/
2809	const value_type&
2810	operator() const* noexcept
2811	{ return _M_match; }
2812
2813	/**
2814	* @brief Selects a %regex_iterator member.
2815	*/
2816	const value_type*
2817	operator->() const noexcept
2818	{ return &_M_match; }
2819
2820	/**
2821	* @brief Increments a %regex_iterator.
2822	*/
2823	regex_iterator&
2824	operator++();
2825
2826	/**
2827	* @brief Postincrements a %regex_iterator.
2828	*/
2829	regex_iterator
2830	operator++(int)
2831	{
2832	auto __tmp = *this;
2833	++(*this);
2834	return __tmp;
2835	}
2836
2837	private:
2838	_Bi_iter _M_begin {};
2839	_Bi_iter _M_end {};
2840	const regex_type* _M_pregex = nullptr;
2841	regex_constants::match_flag_type _M_flags {};
2842	match_results<_Bi_iter> _M_match;
2843	};
2844
2845	typedef regex_iterator<const char*> cregex_iterator;
2846	typedef regex_iterator<string::const_iterator> sregex_iterator;
2847	#ifdef _GLIBCXX_USE_WCHAR_T
2848	typedef regex_iterator<const wchar_t*> wcregex_iterator;
2849	typedef regex_iterator<wstring::const_iterator> wsregex_iterator;
2850	#endif
2851
2852	// [7.12.2] Class template regex_token_iterator
2853	/**
2854	* Iterates over submatches in a range (or @a splits a text string).
2855	*
2856	* The purpose of this iterator is to enumerate all, or all specified,
2857	* matches of a regular expression within a text range. The dereferenced
2858	* value of an iterator of this class is a std::sub_match object.
2859	*
2860	* @headerfile regex
2861	* @since C++11
2862	*/
2863	template<typename _Bi_iter,
2864	typename _Ch_type = typename iterator_traits<_Bi_iter>::value_type,
2865	typename _Rx_traits = regex_traits<_Ch_type> >
2866	class regex_token_iterator
2867	{
2868	public:
2869	typedef basic_regex<_Ch_type, _Rx_traits> regex_type;
2870	typedef sub_match<_Bi_iter> value_type;
2871	typedef std::ptrdiff_t difference_type;
2872	typedef const value_type* pointer;
2873	typedef const value_type& reference;
2874	typedef std::forward_iterator_tag iterator_category;
2875	#if __cplusplus > 201703L
2876	typedef std::input_iterator_tag iterator_concept;
2877	#endif
2878
2879	public:
2880	/**
2881	* @brief Default constructs a %regex_token_iterator.
2882	*
2883	* A default-constructed %regex_token_iterator is a singular iterator
2884	* that will compare equal to the one-past-the-end value for any
2885	* iterator of the same type.
2886	*/
2887	regex_token_iterator()
2888	: _M_position(), _M_subs (), _M_suffix(), _M_n(`0`), _M_result(nullptr),
2889	_M_has_m1(false)
2890	{ }
2891
2892	/**
2893	* Constructs a %regex_token_iterator...
2894	* @param __a [IN] The start of the text to search.
2895	* @param __b [IN] One-past-the-end of the text to search.
2896	* @param __re [IN] The regular expression to search for.
2897	* @param __submatch [IN] Which submatch to return. There are some
2898	* special values for this parameter:
2899	* - -1 each enumerated subexpression does NOT
2900	* match the regular expression (aka field
2901	* splitting)
2902	* - 0 the entire string matching the
2903	* subexpression is returned for each match
2904	* within the text.
2905	* - >0 enumerates only the indicated
2906	* subexpression from a match within the text.
2907	* @param __m [IN] Policy flags for match rules.
2908	*/
2909	regex_token_iterator(_Bi_iter __a, _Bi_iter __b, const regex_type& __re,
2910	int __submatch = `0`,
2911	regex_constants::match_flag_type __m
2912	= regex_constants::match_default)
2913	: _M_position(__a, __b, __re, __m), _M_subs (`1`, __submatch), _M_n(`0`)
2914	{ _M_init(__a, __b); }
2915
2916	/**
2917	* Constructs a %regex_token_iterator...
2918	* @param __a [IN] The start of the text to search.
2919	* @param __b [IN] One-past-the-end of the text to search.
2920	* @param __re [IN] The regular expression to search for.
2921	* @param __submatches [IN] A list of subexpressions to return for each
2922	* regular expression match within the text.
2923	* @param __m [IN] Policy flags for match rules.
2924	*/
2925	regex_token_iterator(_Bi_iter __a, _Bi_iter __b,
2926	const regex_type& __re,
2927	const std::vector<int>& __submatches,
2928	regex_constants::match_flag_type __m
2929	= regex_constants::match_default)
2930	: _M_position(__a, __b, __re, __m), _M_subs (__submatches), _M_n(`0`)
2931	{ _M_init(__a, __b); }
2932
2933	/**
2934	* Constructs a %regex_token_iterator...
2935	* @param __a [IN] The start of the text to search.
2936	* @param __b [IN] One-past-the-end of the text to search.
2937	* @param __re [IN] The regular expression to search for.
2938	* @param __submatches [IN] A list of subexpressions to return for each
2939	* regular expression match within the text.
2940	* @param __m [IN] Policy flags for match rules.
2941	*/
2942	regex_token_iterator(_Bi_iter __a, _Bi_iter __b,
2943	const regex_type& __re,
2944	initializer_list<int> __submatches,
2945	regex_constants::match_flag_type __m
2946	= regex_constants::match_default)
2947	: _M_position(__a, __b, __re, __m), _M_subs (__submatches), _M_n(`0`)
2948	{ _M_init(__a, __b); }
2949
2950	/**
2951	* Constructs a %regex_token_iterator...
2952	* @param __a [IN] The start of the text to search.
2953	* @param __b [IN] One-past-the-end of the text to search.
2954	* @param __re [IN] The regular expression to search for.
2955	* @param __submatches [IN] A list of subexpressions to return for each
2956	* regular expression match within the text.
2957	* @param __m [IN] Policy flags for match rules.
2958	*/
2959	template<std::size_t _Nm>
2960	regex_token_iterator(_Bi_iter __a, _Bi_iter __b,
2961	const regex_type& __re,
2962	const int (&__submatches)[_Nm],
2963	regex_constants::match_flag_type __m
2964	= regex_constants::match_default)
2965	: _M_position(__a, __b, __re, __m),
2966	_M_subs(__submatches, __submatches + _Nm), _M_n(`0`)
2967	{ _M_init(__a, __b); }
2968
2969	// _GLIBCXX_RESOLVE_LIB_DEFECTS
2970	// 2332. regex_token_iterator should forbid temporary regexes
2971	regex_token_iterator(_Bi_iter, _Bi_iter, const regex_type&&, int = `0`,
2972	regex_constants::match_flag_type =
2973	regex_constants::match_default) = delete;
2974	regex_token_iterator(_Bi_iter, _Bi_iter, const regex_type&&,
2975	const std::vector<int>&,
2976	regex_constants::match_flag_type =
2977	regex_constants::match_default) = delete;
2978	regex_token_iterator(_Bi_iter, _Bi_iter, const regex_type&&,
2979	initializer_list<int>,
2980	regex_constants::match_flag_type =
2981	regex_constants::match_default) = delete;
2982	template <std::size_t _Nm>
2983	regex_token_iterator(_Bi_iter, _Bi_iter, const regex_type&&,
2984	const int (&)[_Nm],
2985	regex_constants::match_flag_type =
2986	regex_constants::match_default) = delete;
2987
2988	/**
2989	* @brief Copy constructs a %regex_token_iterator.
2990	* @param __rhs [IN] A %regex_token_iterator to copy.
2991	*/
2992	regex_token_iterator(const regex_token_iterator& __rhs)
2993	: _M_position(__rhs._M_position), _M_subs(__rhs._M_subs),
2994	_M_suffix(__rhs._M_suffix), _M_n(__rhs._M_n), _M_has_m1(__rhs._M_has_m1)
2995	{ _M_normalize_result(); }
2996
2997	/**
2998	* @brief Assigns a %regex_token_iterator to another.
2999	* @param __rhs [IN] A %regex_token_iterator to copy.
3000	*/
3001	regex_token_iterator&
3002	operator=(const regex_token_iterator& __rhs);
3003
3004	/**
3005	* @brief Compares a %regex_token_iterator to another for equality.
3006	*/
3007	bool
3008	operator==(const regex_token_iterator& __rhs) const;
3009
3010	#if __cplusplus >= 202002L
3011	// _GLIBCXX_RESOLVE_LIB_DEFECTS
3012	// 3719. Directory iterators should be usable with default sentinel
3013	bool operator==(default_sentinel_t) const noexcept
3014	{ return _M_end_of_seq(); }
3015	#endif
3016
3017	#if __cpp_impl_three_way_comparison < 201907L
3018	/**
3019	* @brief Compares a %regex_token_iterator to another for inequality.
3020	*/
3021	bool
3022	operator!=(const regex_token_iterator& __rhs) const
3023	{ return !(*this == __rhs); }
3024	#endif
3025
3026	/**
3027	* @brief Dereferences a %regex_token_iterator.
3028	*/
3029	const value_type&
3030	operator() const*
3031	{ return *_M_result; }
3032
3033	/**
3034	* @brief Selects a %regex_token_iterator member.
3035	*/
3036	const value_type*
3037	operator->() const
3038	{ return _M_result; }
3039
3040	/**
3041	* @brief Increments a %regex_token_iterator.
3042	*/
3043	regex_token_iterator&
3044	operator++();
3045
3046	/**
3047	* @brief Postincrements a %regex_token_iterator.
3048	*/
3049	regex_token_iterator
3050	operator++(int)
3051	{
3052	auto __tmp = *this;
3053	++(*this);
3054	return __tmp;
3055	}
3056
3057	private:
3058	typedef regex_iterator<_Bi_iter, _Ch_type, _Rx_traits> _Position;
3059
3060	void
3061	_M_init(_Bi_iter __a, _Bi_iter __b);
3062
3063	const value_type&
3064	_M_current_match() const
3065	{
3066	if (_M_subs [_M_n] == -`1`)
3067	return (*_M_position).prefix();
3068	else
3069	return (*_M_position)[_M_subs [_M_n]];
3070	}
3071
3072	constexpr bool
3073	_M_end_of_seq() const noexcept
3074	{ return _M_result == nullptr; }
3075
3076	// [28.12.2.2.4]
3077	void
3078	_M_normalize_result()
3079	{
3080	if (_M_position != _Position())
3081	_M_result = &_M_current_match();
3082	else if (_M_has_m1)
3083	_M_result = &_M_suffix;
3084	else
3085	_M_result = nullptr;
3086	}
3087
3088	_Position _M_position;
3089	std::vector<int> _M_subs;
3090	value_type _M_suffix;
3091	std::size_t _M_n;
3092	const value_type* _M_result;
3093
3094	// Show whether _M_subs contains -1
3095	bool _M_has_m1;
3096	};
3097
3098	/* @brief Token iterator for C-style NULL-terminated strings. /
3099	typedef regex_token_iterator<const char*> cregex_token_iterator;
3100
3101	/* @brief Token iterator for standard strings. /
3102	typedef regex_token_iterator<string::const_iterator> sregex_token_iterator;
3103
3104	#ifdef _GLIBCXX_USE_WCHAR_T
3105	/* @brief Token iterator for C-style NULL-terminated wide strings. /
3106	typedef regex_token_iterator<const wchar_t*> wcregex_token_iterator;
3107
3108	/* @brief Token iterator for standard wide-character strings. /
3109	typedef regex_token_iterator<wstring::const_iterator> wsregex_token_iterator;
3110	#endif
3111
3112	///@} // group regex
3113
3114	_GLIBCXX_END_NAMESPACE_CXX11
3115	_GLIBCXX_END_NAMESPACE_VERSION
3116	} // namespace
3117
3118	#include <bits/regex.tcc>
3119

Browse the source code of include/c++/14/bits/regex.h