basic_string.h source code [include/c++/11/bits/basic_string.h]

1	// Components for manipulating sequences of characters -- C++ --
2
3	// Copyright (C) 1997-2021 Free Software Foundation, Inc.
4	//
5	// This file is part of the GNU ISO C++ Library. This library is free
6	// software; you can redistribute it and/or modify it under the
7	// terms of the GNU General Public License as published by the
8	// Free Software Foundation; either version 3, or (at your option)
9	// any later version.
10
11	// This library is distributed in the hope that it will be useful,
12	// but WITHOUT ANY WARRANTY; without even the implied warranty of
13	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	// GNU General Public License for more details.
15
16	// Under Section 7 of GPL version 3, you are granted additional
17	// permissions described in the GCC Runtime Library Exception, version
18	// 3.1, as published by the Free Software Foundation.
19
20	// You should have received a copy of the GNU General Public License and
21	// a copy of the GCC Runtime Library Exception along with this program;
22	// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23	// <http://www.gnu.org/licenses/>.
24
25	/* @file bits/basic_string.h*
26	* This is an internal header file, included by other library headers.
27	* Do not attempt to use it directly. @headername{string}
28	*/
29
30	//
31	// ISO C++ 14882: 21 Strings library
32	//
33
34	#ifndef _BASIC_STRING_H
35	#define _BASIC_STRING_H 1
36
37	#pragma GCC system_header
38
39	#include <ext/atomicity.h>
40	#include <ext/alloc_traits.h>
41	#include <debug/debug.h>
42
43	#if __cplusplus >= 201103L
44	#include <initializer_list>
45	#endif
46
47	#if __cplusplus >= 201703L
48	# include <string_view>
49	#endif
50
51	namespace std _GLIBCXX_VISIBILITY(default)
52	{
53	_GLIBCXX_BEGIN_NAMESPACE_VERSION
54
55	#ifdef __cpp_lib_is_constant_evaluated
56	// Support P1032R1 in C++20 (but not P0980R1 yet).
57	# define __cpp_lib_constexpr_string 201811L
58	#elif __cplusplus >= 201703L
59	// Support P0426R1 changes to char_traits in C++17.
60	# define __cpp_lib_constexpr_string 201611L
61	#elif __cplusplus > 201703L
62	#endif
63
64	#if _GLIBCXX_USE_CXX11_ABI
65	_GLIBCXX_BEGIN_NAMESPACE_CXX11
66	/**
67	* @class basic_string basic_string.h <string>
68	* @brief Managing sequences of characters and character-like objects.
69	*
70	* @ingroup strings
71	* @ingroup sequences
72	*
73	* @tparam _CharT Type of character
74	* @tparam _Traits Traits for character type, defaults to
75	* char_traits<_CharT>.
76	* @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
77	*
78	* Meets the requirements of a <a href="tables.html#65">container</a>, a
79	* <a href="tables.html#66">reversible container</a>, and a
80	* <a href="tables.html#67">sequence</a>. Of the
81	* <a href="tables.html#68">optional sequence requirements</a>, only
82	* @c push_back, @c at, and @c %array access are supported.
83	*/
84	template<typename _CharT, typename _Traits, typename _Alloc>
85	class basic_string
86	{
87	typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
88	rebind<_CharT>::other _Char_alloc_type;
89	typedef __gnu_cxx::__alloc_traits<_Char_alloc_type> _Alloc_traits;
90
91	// Types:
92	public:
93	typedef _Traits traits_type;
94	typedef typename _Traits::char_type value_type;
95	typedef _Char_alloc_type allocator_type;
96	typedef typename _Alloc_traits::size_type size_type;
97	typedef typename _Alloc_traits::difference_type difference_type;
98	typedef typename _Alloc_traits::reference reference;
99	typedef typename _Alloc_traits::const_reference const_reference;
100	typedef typename _Alloc_traits::pointer pointer;
101	typedef typename _Alloc_traits::const_pointer const_pointer;
102	typedef __gnu_cxx::__normal_iterator<pointer, basic_string> iterator;
103	typedef __gnu_cxx::__normal_iterator<const_pointer, basic_string>
104	const_iterator;
105	typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
106	typedef std::reverse_iterator<iterator> reverse_iterator;
107
108	/// Value returned by various member functions when they fail.
109	static const size_type npos = static_cast<size_type>(-`1`);
110
111	protected:
112	// type used for positions in insert, erase etc.
113	#if __cplusplus < 201103L
114	typedef iterator __const_iterator;
115	#else
116	typedef const_iterator __const_iterator;
117	#endif
118
119	private:
120	#if __cplusplus >= 201703L
121	// A helper type for avoiding boiler-plate.
122	typedef basic_string_view<_CharT, _Traits> __sv_type;
123
124	template<typename _Tp, typename _Res>
125	using _If_sv = enable_if_t<
126	__and_<is_convertible<const _Tp&, __sv_type>,
127	__not_<is_convertible<const _Tp, const* basic_string*>>,
128	__not_<is_convertible<const _Tp&, const _CharT*>>>::value,
129	_Res>;
130
131	// Allows an implicit conversion to __sv_type.
132	static __sv_type
133	_S_to_string_view(__sv_type __svt) noexcept
134	{ return __svt; }
135
136	// Wraps a string_view by explicit conversion and thus
137	// allows to add an internal constructor that does not
138	// participate in overload resolution when a string_view
139	// is provided.
140	struct __sv_wrapper
141	{
142	explicit __sv_wrapper(__sv_type __sv) noexcept : _M_sv(__sv) { }
143	__sv_type _M_sv;
144	};
145
146	/**
147	* @brief Only internally used: Construct string from a string view
148	* wrapper.
149	* @param __svw string view wrapper.
150	* @param __a Allocator to use.
151	*/
152	explicit
153	basic_string(__sv_wrapper __svw, const _Alloc& __a)
154	: basic_string(__svw._M_sv.data(), __svw._M_sv.size(), __a) { }
155	#endif
156
157	// Use empty-base optimization: http://www.cantrip.org/emptyopt.html
158	struct _Alloc_hider : allocator_type // TODO check __is_final
159	{
160	#if __cplusplus < 201103L
161	_Alloc_hider(pointer __dat, const _Alloc& __a = _Alloc())
162	: allocator_type(__a), _M_p(__dat) { }
163	#else
164	_Alloc_hider(pointer __dat, const _Alloc& __a)
165	: allocator_type(__a), _M_p(__dat) { }
166
167	_Alloc_hider(pointer __dat, _Alloc&& __a = _Alloc())
168	: allocator_type(std::move(__a)), _M_p(__dat) { }
169	#endif
170
171	pointer _M_p; // The actual data.
172	};
173
174	_Alloc_hider _M_dataplus;
175	size_type _M_string_length;
176
177	enum { _S_local_capacity = `15` / sizeof(_CharT) };
178
179	union
180	{
181	_CharT _M_local_buf[_S_local_capacity + `1`];
182	size_type _M_allocated_capacity;
183	};
184
185	void
186	_M_data(pointer __p)
187	{ _M_dataplus._M_p = __p; }
188
189	void
190	_M_length(size_type __length)
191	{ _M_string_length = __length; }
192
193	pointer
194	_M_data() const
195	{ return _M_dataplus._M_p; }
196
197	pointer
198	_M_local_data()
199	{
200	#if __cplusplus >= 201103L
201	return std::pointer_traits<pointer>::pointer_to(*_M_local_buf);
202	#else
203	return pointer(_M_local_buf);
204	#endif
205	}
206
207	const_pointer
208	_M_local_data() const
209	{
210	#if __cplusplus >= 201103L
211	return std::pointer_traits<const_pointer>::pointer_to(*_M_local_buf);
212	#else
213	return const_pointer(_M_local_buf);
214	#endif
215	}
216
217	void
218	_M_capacity(size_type __capacity)
219	{ _M_allocated_capacity = __capacity; }
220
221	void
222	_M_set_length(size_type __n)
223	{
224	_M_length(__n);
225	traits_type::assign(_M_data()[__n], _CharT());
226	}
227
228	bool
229	_M_is_local() const
230	{ return _M_data() == _M_local_data(); }
231
232	// Create & Destroy
233	pointer
234	_M_create(size_type&, size_type);
235
236	void
237	_M_dispose()
238	{
239	if (!_M_is_local())
240	_M_destroy(_M_allocated_capacity);
241	}
242
243	void
244	_M_destroy(size_type __size) throw()
245	{ _Alloc_traits::deallocate(_M_get_allocator(), _M_data(), __size + `1`); }
246
247	// _M_construct_aux is used to implement the 21.3.1 para 15 which
248	// requires special behaviour if _InIterator is an integral type
249	template<typename _InIterator>
250	void
251	_M_construct_aux(_InIterator __beg, _InIterator __end,
252	std::__false_type)
253	{
254	typedef typename iterator_traits<_InIterator>::iterator_category _Tag;
255	_M_construct(__beg, __end, _Tag());
256	}
257
258	// _GLIBCXX_RESOLVE_LIB_DEFECTS
259	// 438. Ambiguity in the "do the right thing" clause
260	template<typename _Integer>
261	void
262	_M_construct_aux(_Integer __beg, _Integer __end, std::__true_type)
263	{ _M_construct_aux_2(static_cast<size_type>(__beg), __end); }
264
265	void
266	_M_construct_aux_2(size_type __req, _CharT __c)
267	{ _M_construct(__req, __c); }
268
269	template<typename _InIterator>
270	void
271	_M_construct(_InIterator __beg, _InIterator __end)
272	{
273	typedef typename std::__is_integer<_InIterator>::__type _Integral;
274	_M_construct_aux(__beg, __end, _Integral());
275	}
276
277	// For Input Iterators, used in istreambuf_iterators, etc.
278	template<typename _InIterator>
279	void
280	_M_construct(_InIterator __beg, _InIterator __end,
281	std::input_iterator_tag);
282
283	// For forward_iterators up to random_access_iterators, used for
284	// string::iterator, _CharT, etc.*
285	template<typename _FwdIterator>
286	void
287	_M_construct(_FwdIterator __beg, _FwdIterator __end,
288	std::forward_iterator_tag);
289
290	void
291	_M_construct(size_type __req, _CharT __c);
292
293	allocator_type&
294	_M_get_allocator()
295	{ return _M_dataplus; }
296
297	const allocator_type&
298	_M_get_allocator() const
299	{ return _M_dataplus; }
300
301	private:
302
303	#ifdef _GLIBCXX_DISAMBIGUATE_REPLACE_INST
304	// The explicit instantiations in misc-inst.cc require this due to
305	// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64063
306	template<typename _Tp, bool _Requires =
307	!__are_same<_Tp, _CharT*>::__value
308	&& !__are_same<_Tp, const _CharT*>::__value
309	&& !__are_same<_Tp, iterator>::__value
310	&& !__are_same<_Tp, const_iterator>::__value>
311	struct __enable_if_not_native_iterator
312	{ typedef basic_string& __type; };
313	template<typename _Tp>
314	struct __enable_if_not_native_iterator<_Tp, false> { };
315	#endif
316
317	size_type
318	_M_check(size_type __pos, const char* __s) const
319	{
320	if (__pos > this->size())
321	__throw_out_of_range_fmt(__N("%s: __pos (which is %zu) > "
322	"this->size() (which is %zu)"),
323	__s, __pos, this->size());
324	return __pos;
325	}
326
327	void
328	_M_check_length(size_type __n1, size_type __n2, const char* __s) const
329	{
330	if (this->max_size() - (this->size() - __n1) < __n2)
331	__throw_length_error(__N(__s));
332	}
333
334
335	// NB: _M_limit doesn't check for a bad __pos value.
336	size_type
337	_M_limit(size_type __pos, size_type __off) const _GLIBCXX_NOEXCEPT
338	{
339	const bool __testoff = __off < this->size() - __pos;
340	return __testoff ? __off : this->size() - __pos;
341	}
342
343	// True if _Rep and source do not overlap.
344	bool
345	_M_disjunct(const _CharT* __s) const _GLIBCXX_NOEXCEPT
346	{
347	return (less<const _CharT*>()(__s, _M_data())
348	\|\| less<const _CharT>()(_M_data() + this*->size(), __s));
349	}
350
351	// When __n = 1 way faster than the general multichar
352	// traits_type::copy/move/assign.
353	static void
354	_S_copy(_CharT* __d, const _CharT* __s, size_type __n)
355	{
356	if (__n == `1`)
357	traits_type::assign(__d, __s);
358	else
359	traits_type::copy(__d, __s, __n);
360	}
361
362	static void
363	_S_move(_CharT* __d, const _CharT* __s, size_type __n)
364	{
365	if (__n == `1`)
366	traits_type::assign(__d, __s);
367	else
368	traits_type::move(__d, __s, __n);
369	}
370
371	static void
372	_S_assign(_CharT* __d, size_type __n, _CharT __c)
373	{
374	if (__n == `1`)
375	traits_type::assign(*__d, __c);
376	else
377	traits_type::assign(__d, __n, __c);
378	}
379
380	// _S_copy_chars is a separate template to permit specialization
381	// to optimize for the common case of pointers as iterators.
382	template<class _Iterator>
383	static void
384	_S_copy_chars(_CharT* __p, _Iterator __k1, _Iterator __k2)
385	{
386	for (; __k1 != __k2; ++__k1, (void)++__p)
387	traits_type::assign(__p, __k1); // These types are off.
388	}
389
390	static void
391	_S_copy_chars(_CharT* __p, iterator __k1, iterator __k2) _GLIBCXX_NOEXCEPT
392	{ _S_copy_chars(__p, __k1.base(), __k2.base()); }
393
394	static void
395	_S_copy_chars(_CharT* __p, const_iterator __k1, const_iterator __k2)
396	_GLIBCXX_NOEXCEPT
397	{ _S_copy_chars(__p, __k1.base(), __k2.base()); }
398
399	static void
400	_S_copy_chars(_CharT* __p, _CharT* __k1, _CharT* __k2) _GLIBCXX_NOEXCEPT
401	{ _S_copy(__p, __k1, __k2 - __k1); }
402
403	static void
404	_S_copy_chars(_CharT* __p, const _CharT* __k1, const _CharT* __k2)
405	_GLIBCXX_NOEXCEPT
406	{ _S_copy(__p, __k1, __k2 - __k1); }
407
408	static int
409	_S_compare(size_type __n1, size_type __n2) _GLIBCXX_NOEXCEPT
410	{
411	const difference_type __d = difference_type(__n1 - __n2);
412
413	if (__d > __gnu_cxx::__numeric_traits<int>::__max)
414	return __gnu_cxx::__numeric_traits<int>::__max;
415	else if (__d < __gnu_cxx::__numeric_traits<int>::__min)
416	return __gnu_cxx::__numeric_traits<int>::__min;
417	else
418	return int(__d);
419	}
420
421	void
422	_M_assign(const basic_string&);
423
424	void
425	_M_mutate(size_type __pos, size_type __len1, const _CharT* __s,
426	size_type __len2);
427
428	void
429	_M_erase(size_type __pos, size_type __n);
430
431	public:
432	// Construct/copy/destroy:
433	// NB: We overload ctors in some cases instead of using default
434	// arguments, per 17.4.4.4 para. 2 item 2.
435
436	/**
437	* @brief Default constructor creates an empty string.
438	*/
439	basic_string()
440	_GLIBCXX_NOEXCEPT_IF(is_nothrow_default_constructible<_Alloc>::value)
441	: _M_dataplus(_M_local_data())
442	{ _M_set_length(`0`); }
443
444	/**
445	* @brief Construct an empty string using allocator @a a.
446	*/
447	explicit
448	basic_string(const _Alloc& __a) _GLIBCXX_NOEXCEPT
449	: _M_dataplus(_M_local_data(), __a)
450	{ _M_set_length(`0`); }
451
452	/**
453	* @brief Construct string with copy of value of @a __str.
454	* @param __str Source string.
455	*/
456	basic_string(const basic_string& __str)
457	: _M_dataplus(_M_local_data(),
458	_Alloc_traits::_S_select_on_copy(__str._M_get_allocator()))
459	{ _M_construct(__str._M_data(), __str._M_data() + __str.length()); }
460
461	// _GLIBCXX_RESOLVE_LIB_DEFECTS
462	// 2583. no way to supply an allocator for basic_string(str, pos)
463	/**
464	* @brief Construct string as copy of a substring.
465	* @param __str Source string.
466	* @param __pos Index of first character to copy from.
467	* @param __a Allocator to use.
468	*/
469	basic_string(const basic_string& __str, size_type __pos,
470	const _Alloc& __a = _Alloc())
471	: _M_dataplus(_M_local_data(), __a)
472	{
473	const _CharT* __start = __str._M_data()
474	+ __str._M_check(__pos, "basic_string::basic_string");
475	_M_construct(__start, __start + __str._M_limit(__pos, npos));
476	}
477
478	/**
479	* @brief Construct string as copy of a substring.
480	* @param __str Source string.
481	* @param __pos Index of first character to copy from.
482	* @param __n Number of characters to copy.
483	*/
484	basic_string(const basic_string& __str, size_type __pos,
485	size_type __n)
486	: _M_dataplus(_M_local_data())
487	{
488	const _CharT* __start = __str._M_data()
489	+ __str._M_check(__pos, "basic_string::basic_string");
490	_M_construct(__start, __start + __str._M_limit(__pos, __n));
491	}
492
493	/**
494	* @brief Construct string as copy of a substring.
495	* @param __str Source string.
496	* @param __pos Index of first character to copy from.
497	* @param __n Number of characters to copy.
498	* @param __a Allocator to use.
499	*/
500	basic_string(const basic_string& __str, size_type __pos,
501	size_type __n, const _Alloc& __a)
502	: _M_dataplus(_M_local_data(), __a)
503	{
504	const _CharT* __start
505	= __str._M_data() + __str._M_check(__pos, "string::string");
506	_M_construct(__start, __start + __str._M_limit(__pos, __n));
507	}
508
509	/**
510	* @brief Construct string initialized by a character %array.
511	* @param __s Source character %array.
512	* @param __n Number of characters to copy.
513	* @param __a Allocator to use (default is default allocator).
514	*
515	* NB: @a __s must have at least @a __n characters, '\\0'
516	* has no special meaning.
517	*/
518	basic_string(const _CharT* __s, size_type __n,
519	const _Alloc& __a = _Alloc())
520	: _M_dataplus(_M_local_data(), __a)
521	{ _M_construct(__s, __s + __n); }
522
523	/**
524	* @brief Construct string as copy of a C string.
525	* @param __s Source C string.
526	* @param __a Allocator to use (default is default allocator).
527	*/
528	#if __cpp_deduction_guides && ! defined _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
529	// _GLIBCXX_RESOLVE_LIB_DEFECTS
530	// 3076. basic_string CTAD ambiguity
531	template<typename = _RequireAllocator<_Alloc>>
532	#endif
533	basic_string(const _CharT* __s, const _Alloc& __a = _Alloc())
534	: _M_dataplus(_M_local_data(), __a)
535	{
536	const _CharT* __end = __s ? __s + traits_type::length(__s)
537	// We just need a non-null pointer here to get an exception:
538	: reinterpret_cast<const _CharT>(__alignof__*(_CharT));
539	_M_construct(__s, __end, random_access_iterator_tag ());
540	}
541
542	/**
543	* @brief Construct string as multiple characters.
544	* @param __n Number of characters.
545	* @param __c Character to use.
546	* @param __a Allocator to use (default is default allocator).
547	*/
548	#if __cpp_deduction_guides && ! defined _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
549	// _GLIBCXX_RESOLVE_LIB_DEFECTS
550	// 3076. basic_string CTAD ambiguity
551	template<typename = _RequireAllocator<_Alloc>>
552	#endif
553	basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc())
554	: _M_dataplus(_M_local_data(), __a)
555	{ _M_construct(__n, __c); }
556
557	#if __cplusplus >= 201103L
558	/**
559	* @brief Move construct string.
560	* @param __str Source string.
561	*
562	* The newly-created string contains the exact contents of @a __str.
563	* @a __str is a valid, but unspecified string.
564	*/
565	basic_string(basic_string&& __str) noexcept
566	: _M_dataplus(_M_local_data(), std::move(__str._M_get_allocator()))
567	{
568	if (__str._M_is_local())
569	{
570	traits_type::copy(_M_local_buf, __str._M_local_buf,
571	_S_local_capacity + `1`);
572	}
573	else
574	{
575	_M_data(__str._M_data());
576	_M_capacity(__str._M_allocated_capacity);
577	}
578
579	// Must use _M_length() here not _M_set_length() because
580	// basic_stringbuf relies on writing into unallocated capacity so
581	// we mess up the contents if we put a '\0' in the string.
582	_M_length(__str.length());
583	__str._M_data(__str._M_local_data());
584	__str._M_set_length(`0`);
585	}
586
587	/**
588	* @brief Construct string from an initializer %list.
589	* @param __l std::initializer_list of characters.
590	* @param __a Allocator to use (default is default allocator).
591	*/
592	basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc())
593	: _M_dataplus(_M_local_data(), __a)
594	{ _M_construct(__l.begin(), __l.end()); }
595
596	basic_string(const basic_string& __str, const _Alloc& __a)
597	: _M_dataplus(_M_local_data(), __a)
598	{ _M_construct(__str.begin(), __str.end()); }
599
600	basic_string(basic_string&& __str, const _Alloc& __a)
601	noexcept(_Alloc_traits::_S_always_equal())
602	: _M_dataplus(_M_local_data(), __a)
603	{
604	if (__str._M_is_local())
605	{
606	traits_type::copy(_M_local_buf, __str._M_local_buf,
607	_S_local_capacity + `1`);
608	_M_length(__str.length());
609	__str._M_set_length(`0`);
610	}
611	else if (_Alloc_traits::_S_always_equal()
612	\|\| __str.get_allocator() == __a)
613	{
614	_M_data(__str._M_data());
615	_M_length(__str.length());
616	_M_capacity(__str._M_allocated_capacity);
617	__str._M_data(__str._M_local_buf);
618	__str._M_set_length(`0`);
619	}
620	else
621	_M_construct(__str.begin(), __str.end());
622	}
623
624	#endif // C++11
625
626	/**
627	* @brief Construct string as copy of a range.
628	* @param __beg Start of range.
629	* @param __end End of range.
630	* @param __a Allocator to use (default is default allocator).
631	*/
632	#if __cplusplus >= 201103L
633	template<typename _InputIterator,
634	typename = std::_RequireInputIter<_InputIterator>>
635	#else
636	template<typename _InputIterator>
637	#endif
638	basic_string(_InputIterator __beg, _InputIterator __end,
639	const _Alloc& __a = _Alloc())
640	: _M_dataplus(_M_local_data(), __a)
641	{ _M_construct(__beg, __end); }
642
643	#if __cplusplus >= 201703L
644	/**
645	* @brief Construct string from a substring of a string_view.
646	* @param __t Source object convertible to string view.
647	* @param __pos The index of the first character to copy from __t.
648	* @param __n The number of characters to copy from __t.
649	* @param __a Allocator to use.
650	*/
651	template<typename _Tp, typename = _If_sv<_Tp, void>>
652	basic_string(const _Tp& __t, size_type __pos, size_type __n,
653	const _Alloc& __a = _Alloc())
654	: basic_string(_S_to_string_view(__t).substr(__pos, __n), __a) { }
655
656	/**
657	* @brief Construct string from a string_view.
658	* @param __t Source object convertible to string view.
659	* @param __a Allocator to use (default is default allocator).
660	*/
661	template<typename _Tp, typename = _If_sv<_Tp, void>>
662	explicit
663	basic_string(const _Tp& __t, const _Alloc& __a = _Alloc())
664	: basic_string(__sv_wrapper(_S_to_string_view(__t)), __a) { }
665	#endif // C++17
666
667	/**
668	* @brief Destroy the string instance.
669	*/
670	~basic_string()
671	{ _M_dispose(); }
672
673	/**
674	* @brief Assign the value of @a str to this string.
675	* @param __str Source string.
676	*/
677	basic_string&
678	operator=(const basic_string& __str)
679	{
680	return this->assign(__str);
681	}
682
683	/**
684	* @brief Copy contents of @a s into this string.
685	* @param __s Source null-terminated string.
686	*/
687	basic_string&
688	operator=(const _CharT* __s)
689	{ return this->assign(__s); }
690
691	/**
692	* @brief Set value to string of length 1.
693	* @param __c Source character.
694	*
695	* Assigning to a character makes this string length 1 and
696	* (*this)[0] == @a c.
697	*/
698	basic_string&
699	operator=(_CharT __c)
700	{
701	this->assign(`1`, __c);
702	return *this;
703	}
704
705	#if __cplusplus >= 201103L
706	/**
707	* @brief Move assign the value of @a str to this string.
708	* @param __str Source string.
709	*
710	* The contents of @a str are moved into this string (without copying).
711	* @a str is a valid, but unspecified string.
712	*/
713	// _GLIBCXX_RESOLVE_LIB_DEFECTS
714	// 2063. Contradictory requirements for string move assignment
715	basic_string&
716	operator=(basic_string&& __str)
717	noexcept(_Alloc_traits::_S_nothrow_move())
718	{
719	if (!_M_is_local() && _Alloc_traits::_S_propagate_on_move_assign()
720	&& !_Alloc_traits::_S_always_equal()
721	&& _M_get_allocator() != __str._M_get_allocator())
722	{
723	// Destroy existing storage before replacing allocator.
724	_M_destroy(_M_allocated_capacity);
725	_M_data(_M_local_data());
726	_M_set_length(`0`);
727	}
728	// Replace allocator if POCMA is true.
729	std::__alloc_on_move(_M_get_allocator(), __str._M_get_allocator());
730
731	if (__str._M_is_local())
732	{
733	// We've always got room for a short string, just copy it
734	// (unless this is a self-move, because that would violate the
735	// char_traits::copy precondition that the ranges don't overlap).
736	if (__builtin_expect(std::__addressof(__str) != this, true))
737	{
738	if (__str.size())
739	this->_S_copy(_M_data(), __str._M_data(), __str.size());
740	_M_set_length(__str.size());
741	}
742	}
743	else if (_Alloc_traits::_S_propagate_on_move_assign()
744	\|\| _Alloc_traits::_S_always_equal()
745	\|\| _M_get_allocator() == __str._M_get_allocator())
746	{
747	// Just move the allocated pointer, our allocator can free it.
748	pointer __data = nullptr;
749	size_type __capacity;
750	if (!_M_is_local())
751	{
752	if (_Alloc_traits::_S_always_equal())
753	{
754	// __str can reuse our existing storage.
755	__data = _M_data();
756	__capacity = _M_allocated_capacity;
757	}
758	else // __str can't use it, so free it.
759	_M_destroy(_M_allocated_capacity);
760	}
761
762	_M_data(__str._M_data());
763	_M_length(__str.length());
764	_M_capacity(__str._M_allocated_capacity);
765	if (__data)
766	{
767	__str._M_data(__data);
768	__str._M_capacity(__capacity);
769	}
770	else
771	__str._M_data(__str._M_local_buf);
772	}
773	else // Need to do a deep copy
774	assign(__str);
775	__str.clear();
776	return *this;
777	}
778
779	/**
780	* @brief Set value to string constructed from initializer %list.
781	* @param __l std::initializer_list.
782	*/
783	basic_string&
784	operator=(initializer_list<_CharT> __l)
785	{
786	this->assign(__l.begin(), __l.size());
787	return *this;
788	}
789	#endif // C++11
790
791	#if __cplusplus >= 201703L
792	/**
793	* @brief Set value to string constructed from a string_view.
794	* @param __svt An object convertible to string_view.
795	*/
796	template<typename _Tp>
797	_If_sv<_Tp, basic_string&>
798	operator=(const _Tp& __svt)
799	{ return this->assign(__svt); }
800
801	/**
802	* @brief Convert to a string_view.
803	* @return A string_view.
804	*/
805	operator __sv_type() const noexcept
806	{ return __sv_type(data(), size()); }
807	#endif // C++17
808
809	// Iterators:
810	/**
811	* Returns a read/write iterator that points to the first character in
812	* the %string.
813	*/
814	iterator
815	begin() _GLIBCXX_NOEXCEPT
816	{ return iterator(_M_data()); }
817
818	/**
819	* Returns a read-only (constant) iterator that points to the first
820	* character in the %string.
821	*/
822	const_iterator
823	begin() const _GLIBCXX_NOEXCEPT
824	{ return const_iterator(_M_data()); }
825
826	/**
827	* Returns a read/write iterator that points one past the last
828	* character in the %string.
829	*/
830	iterator
831	end() _GLIBCXX_NOEXCEPT
832	{ return iterator(_M_data() + this->size()); }
833
834	/**
835	* Returns a read-only (constant) iterator that points one past the
836	* last character in the %string.
837	*/
838	const_iterator
839	end() const _GLIBCXX_NOEXCEPT
840	{ return const_iterator(_M_data() + this->size()); }
841
842	/**
843	* Returns a read/write reverse iterator that points to the last
844	* character in the %string. Iteration is done in reverse element
845	* order.
846	*/
847	reverse_iterator
848	rbegin() _GLIBCXX_NOEXCEPT
849	{ return reverse_iterator(this->end()); }
850
851	/**
852	* Returns a read-only (constant) reverse iterator that points
853	* to the last character in the %string. Iteration is done in
854	* reverse element order.
855	*/
856	const_reverse_iterator
857	rbegin() const _GLIBCXX_NOEXCEPT
858	{ return const_reverse_iterator(this->end()); }
859
860	/**
861	* Returns a read/write reverse iterator that points to one before the
862	* first character in the %string. Iteration is done in reverse
863	* element order.
864	*/
865	reverse_iterator
866	rend() _GLIBCXX_NOEXCEPT
867	{ return reverse_iterator(this->begin()); }
868
869	/**
870	* Returns a read-only (constant) reverse iterator that points
871	* to one before the first character in the %string. Iteration
872	* is done in reverse element order.
873	*/
874	const_reverse_iterator
875	rend() const _GLIBCXX_NOEXCEPT
876	{ return const_reverse_iterator(this->begin()); }
877
878	#if __cplusplus >= 201103L
879	/**
880	* Returns a read-only (constant) iterator that points to the first
881	* character in the %string.
882	*/
883	const_iterator
884	cbegin() const noexcept
885	{ return const_iterator(this->_M_data()); }
886
887	/**
888	* Returns a read-only (constant) iterator that points one past the
889	* last character in the %string.
890	*/
891	const_iterator
892	cend() const noexcept
893	{ return const_iterator(this->_M_data() + this->size()); }
894
895	/**
896	* Returns a read-only (constant) reverse iterator that points
897	* to the last character in the %string. Iteration is done in
898	* reverse element order.
899	*/
900	const_reverse_iterator
901	crbegin() const noexcept
902	{ return const_reverse_iterator(this->end()); }
903
904	/**
905	* Returns a read-only (constant) reverse iterator that points
906	* to one before the first character in the %string. Iteration
907	* is done in reverse element order.
908	*/
909	const_reverse_iterator
910	crend() const noexcept
911	{ return const_reverse_iterator(this->begin()); }
912	#endif
913
914	public:
915	// Capacity:
916	/// Returns the number of characters in the string, not including any
917	/// null-termination.
918	size_type
919	size() const _GLIBCXX_NOEXCEPT
920	{ return _M_string_length; }
921
922	/// Returns the number of characters in the string, not including any
923	/// null-termination.
924	size_type
925	length() const _GLIBCXX_NOEXCEPT
926	{ return _M_string_length; }
927
928	/// Returns the size() of the largest possible %string.
929	size_type
930	max_size() const _GLIBCXX_NOEXCEPT
931	{ return (_Alloc_traits::max_size(_M_get_allocator()) - `1`) / `2`; }
932
933	/**
934	* @brief Resizes the %string to the specified number of characters.
935	* @param __n Number of characters the %string should contain.
936	* @param __c Character to fill any new elements.
937	*
938	* This function will %resize the %string to the specified
939	* number of characters. If the number is smaller than the
940	* %string's current size the %string is truncated, otherwise
941	* the %string is extended and new elements are %set to @a __c.
942	*/
943	void
944	resize(size_type __n, _CharT __c);
945
946	/**
947	* @brief Resizes the %string to the specified number of characters.
948	* @param __n Number of characters the %string should contain.
949	*
950	* This function will resize the %string to the specified length. If
951	* the new size is smaller than the %string's current size the %string
952	* is truncated, otherwise the %string is extended and new characters
953	* are default-constructed. For basic types such as char, this means
954	* setting them to 0.
955	*/
956	void
957	resize(size_type __n)
958	{ this->resize(__n, _CharT()); }
959
960	#if __cplusplus >= 201103L
961	#pragma GCC diagnostic push
962	#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
963	/// A non-binding request to reduce capacity() to size().
964	void
965	shrink_to_fit() noexcept
966	{ reserve(); }
967	#pragma GCC diagnostic pop
968	#endif
969
970	/**
971	* Returns the total number of characters that the %string can hold
972	* before needing to allocate more memory.
973	*/
974	size_type
975	capacity() const _GLIBCXX_NOEXCEPT
976	{
977	return _M_is_local() ? size_type(_S_local_capacity)
978	: _M_allocated_capacity;
979	}
980
981	/**
982	* @brief Attempt to preallocate enough memory for specified number of
983	* characters.
984	* @param __res_arg Number of characters required.
985	* @throw std::length_error If @a __res_arg exceeds @c max_size().
986	*
987	* This function attempts to reserve enough memory for the
988	* %string to hold the specified number of characters. If the
989	* number requested is more than max_size(), length_error is
990	* thrown.
991	*
992	* The advantage of this function is that if optimal code is a
993	* necessity and the user can determine the string length that will be
994	* required, the user can reserve the memory in %advance, and thus
995	* prevent a possible reallocation of memory and copying of %string
996	* data.
997	*/
998	void
999	reserve(size_type __res_arg);
1000
1001	/**
1002	* Equivalent to shrink_to_fit().
1003	*/
1004	#if __cplusplus > 201703L
1005	[[deprecated("use shrink_to_fit() instead")]]
1006	#endif
1007	void
1008	reserve();
1009
1010	/**
1011	* Erases the string, making it empty.
1012	*/
1013	void
1014	clear() _GLIBCXX_NOEXCEPT
1015	{ _M_set_length(`0`); }
1016
1017	/**
1018	* Returns true if the %string is empty. Equivalent to
1019	* <code>*this == ""</code>.
1020	*/
1021	_GLIBCXX_NODISCARD bool
1022	empty() const _GLIBCXX_NOEXCEPT
1023	{ return this->size() == `0`; }
1024
1025	// Element access:
1026	/**
1027	* @brief Subscript access to the data contained in the %string.
1028	* @param __pos The index of the character to access.
1029	* @return Read-only (constant) reference to the character.
1030	*
1031	* This operator allows for easy, array-style, data access.
1032	* Note that data access with this operator is unchecked and
1033	* out_of_range lookups are not defined. (For checked lookups
1034	* see at().)
1035	*/
1036	const_reference
1037	operator[] (size_type __pos) const _GLIBCXX_NOEXCEPT
1038	{
1039	__glibcxx_assert(__pos <= size());
1040	return _M_data()[__pos];
1041	}
1042
1043	/**
1044	* @brief Subscript access to the data contained in the %string.
1045	* @param __pos The index of the character to access.
1046	* @return Read/write reference to the character.
1047	*
1048	* This operator allows for easy, array-style, data access.
1049	* Note that data access with this operator is unchecked and
1050	* out_of_range lookups are not defined. (For checked lookups
1051	* see at().)
1052	*/
1053	reference
1054	operator[](size_type __pos)
1055	{
1056	// Allow pos == size() both in C++98 mode, as v3 extension,
1057	// and in C++11 mode.
1058	__glibcxx_assert(__pos <= size());
1059	// In pedantic mode be strict in C++98 mode.
1060	_GLIBCXX_DEBUG_PEDASSERT(__cplusplus >= `201103L` \|\| __pos < size());
1061	return _M_data()[__pos];
1062	}
1063
1064	/**
1065	* @brief Provides access to the data contained in the %string.
1066	* @param __n The index of the character to access.
1067	* @return Read-only (const) reference to the character.
1068	* @throw std::out_of_range If @a n is an invalid index.
1069	*
1070	* This function provides for safer data access. The parameter is
1071	* first checked that it is in the range of the string. The function
1072	* throws out_of_range if the check fails.
1073	*/
1074	const_reference
1075	at(size_type __n) const
1076	{
1077	if (__n >= this->size())
1078	__throw_out_of_range_fmt(__N("basic_string::at: __n "
1079	"(which is %zu) >= this->size() "
1080	"(which is %zu)"),
1081	__n, this->size());
1082	return _M_data()[__n];
1083	}
1084
1085	/**
1086	* @brief Provides access to the data contained in the %string.
1087	* @param __n The index of the character to access.
1088	* @return Read/write reference to the character.
1089	* @throw std::out_of_range If @a n is an invalid index.
1090	*
1091	* This function provides for safer data access. The parameter is
1092	* first checked that it is in the range of the string. The function
1093	* throws out_of_range if the check fails.
1094	*/
1095	reference
1096	at(size_type __n)
1097	{
1098	if (__n >= size())
1099	__throw_out_of_range_fmt(__N("basic_string::at: __n "
1100	"(which is %zu) >= this->size() "
1101	"(which is %zu)"),
1102	__n, this->size());
1103	return _M_data()[__n];
1104	}
1105
1106	#if __cplusplus >= 201103L
1107	/**
1108	* Returns a read/write reference to the data at the first
1109	* element of the %string.
1110	*/
1111	reference
1112	front() noexcept
1113	{
1114	__glibcxx_assert(!empty());
1115	return operator[](`0`);
1116	}
1117
1118	/**
1119	* Returns a read-only (constant) reference to the data at the first
1120	* element of the %string.
1121	*/
1122	const_reference
1123	front() const noexcept
1124	{
1125	__glibcxx_assert(!empty());
1126	return operator[](`0`);
1127	}
1128
1129	/**
1130	* Returns a read/write reference to the data at the last
1131	* element of the %string.
1132	*/
1133	reference
1134	back() noexcept
1135	{
1136	__glibcxx_assert(!empty());
1137	return operator[](this->size() - `1`);
1138	}
1139
1140	/**
1141	* Returns a read-only (constant) reference to the data at the
1142	* last element of the %string.
1143	*/
1144	const_reference
1145	back() const noexcept
1146	{
1147	__glibcxx_assert(!empty());
1148	return operator[](this->size() - `1`);
1149	}
1150	#endif
1151
1152	// Modifiers:
1153	/**
1154	* @brief Append a string to this string.
1155	* @param __str The string to append.
1156	* @return Reference to this string.
1157	*/
1158	basic_string&
1159	operator+=(const basic_string& __str)
1160	{ return this->append(__str); }
1161
1162	/**
1163	* @brief Append a C string.
1164	* @param __s The C string to append.
1165	* @return Reference to this string.
1166	*/
1167	basic_string&
1168	operator+=(const _CharT* __s)
1169	{ return this->append(__s); }
1170
1171	/**
1172	* @brief Append a character.
1173	* @param __c The character to append.
1174	* @return Reference to this string.
1175	*/
1176	basic_string&
1177	operator+=(_CharT __c)
1178	{
1179	this->push_back(__c);
1180	return *this;
1181	}
1182
1183	#if __cplusplus >= 201103L
1184	/**
1185	* @brief Append an initializer_list of characters.
1186	* @param __l The initializer_list of characters to be appended.
1187	* @return Reference to this string.
1188	*/
1189	basic_string&
1190	operator+=(initializer_list<_CharT> __l)
1191	{ return this->append(__l.begin(), __l.size()); }
1192	#endif // C++11
1193
1194	#if __cplusplus >= 201703L
1195	/**
1196	* @brief Append a string_view.
1197	* @param __svt An object convertible to string_view to be appended.
1198	* @return Reference to this string.
1199	*/
1200	template<typename _Tp>
1201	_If_sv<_Tp, basic_string&>
1202	operator+=(const _Tp& __svt)
1203	{ return this->append(__svt); }
1204	#endif // C++17
1205
1206	/**
1207	* @brief Append a string to this string.
1208	* @param __str The string to append.
1209	* @return Reference to this string.
1210	*/
1211	basic_string&
1212	append(const basic_string& __str)
1213	{ return _M_append(__str._M_data(), __str.size()); }
1214
1215	/**
1216	* @brief Append a substring.
1217	* @param __str The string to append.
1218	* @param __pos Index of the first character of str to append.
1219	* @param __n The number of characters to append.
1220	* @return Reference to this string.
1221	* @throw std::out_of_range if @a __pos is not a valid index.
1222	*
1223	* This function appends @a __n characters from @a __str
1224	* starting at @a __pos to this string. If @a __n is is larger
1225	* than the number of available characters in @a __str, the
1226	* remainder of @a __str is appended.
1227	*/
1228	basic_string&
1229	append(const basic_string& __str, size_type __pos, size_type __n = npos)
1230	{ return _M_append(__str._M_data()
1231	+ __str._M_check(__pos, "basic_string::append"),
1232	__str._M_limit(__pos, __n)); }
1233
1234	/**
1235	* @brief Append a C substring.
1236	* @param __s The C string to append.
1237	* @param __n The number of characters to append.
1238	* @return Reference to this string.
1239	*/
1240	basic_string&
1241	append(const _CharT* __s, size_type __n)
1242	{
1243	__glibcxx_requires_string_len(__s, __n);
1244	_M_check_length(size_type(`0`), __n, "basic_string::append");
1245	return _M_append(__s, __n);
1246	}
1247
1248	/**
1249	* @brief Append a C string.
1250	* @param __s The C string to append.
1251	* @return Reference to this string.
1252	*/
1253	basic_string&
1254	append(const _CharT* __s)
1255	{
1256	__glibcxx_requires_string(__s);
1257	const size_type __n = traits_type::length(__s);
1258	_M_check_length(size_type(`0`), __n, "basic_string::append");
1259	return _M_append(__s, __n);
1260	}
1261
1262	/**
1263	* @brief Append multiple characters.
1264	* @param __n The number of characters to append.
1265	* @param __c The character to use.
1266	* @return Reference to this string.
1267	*
1268	* Appends __n copies of __c to this string.
1269	*/
1270	basic_string&
1271	append(size_type __n, _CharT __c)
1272	{ return _M_replace_aux(this->size(), size_type(`0`), __n, __c); }
1273
1274	#if __cplusplus >= 201103L
1275	/**
1276	* @brief Append an initializer_list of characters.
1277	* @param __l The initializer_list of characters to append.
1278	* @return Reference to this string.
1279	*/
1280	basic_string&
1281	append(initializer_list<_CharT> __l)
1282	{ return this->append(__l.begin(), __l.size()); }
1283	#endif // C++11
1284
1285	/**
1286	* @brief Append a range of characters.
1287	* @param __first Iterator referencing the first character to append.
1288	* @param __last Iterator marking the end of the range.
1289	* @return Reference to this string.
1290	*
1291	* Appends characters in the range [__first,__last) to this string.
1292	*/
1293	#if __cplusplus >= 201103L
1294	template<class _InputIterator,
1295	typename = std::_RequireInputIter<_InputIterator>>
1296	#else
1297	template<class _InputIterator>
1298	#endif
1299	basic_string&
1300	append(_InputIterator __first, _InputIterator __last)
1301	{ return this->replace(end(), end(), __first, __last); }
1302
1303	#if __cplusplus >= 201703L
1304	/**
1305	* @brief Append a string_view.
1306	* @param __svt An object convertible to string_view to be appended.
1307	* @return Reference to this string.
1308	*/
1309	template<typename _Tp>
1310	_If_sv<_Tp, basic_string&>
1311	append(const _Tp& __svt)
1312	{
1313	__sv_type __sv = __svt;
1314	return this->append(__sv.data(), __sv.size());
1315	}
1316
1317	/**
1318	* @brief Append a range of characters from a string_view.
1319	* @param __svt An object convertible to string_view to be appended from.
1320	* @param __pos The position in the string_view to append from.
1321	* @param __n The number of characters to append from the string_view.
1322	* @return Reference to this string.
1323	*/
1324	template<typename _Tp>
1325	_If_sv<_Tp, basic_string&>
1326	append(const _Tp& __svt, size_type __pos, size_type __n = npos)
1327	{
1328	__sv_type __sv = __svt;
1329	return _M_append(__sv.data()
1330	+ std::__sv_check(__sv.size(), __pos, "basic_string::append"),
1331	std::__sv_limit(__sv.size(), __pos, __n));
1332	}
1333	#endif // C++17
1334
1335	/**
1336	* @brief Append a single character.
1337	* @param __c Character to append.
1338	*/
1339	void
1340	push_back(_CharT __c)
1341	{
1342	const size_type __size = this->size();
1343	if (__size + `1` > this->capacity())
1344	this->_M_mutate(__size, size_type(`0`), `0`, size_type(`1`));
1345	traits_type::assign(this->_M_data()[__size], __c);
1346	this->_M_set_length(__size + `1`);
1347	}
1348
1349	/**
1350	* @brief Set value to contents of another string.
1351	* @param __str Source string to use.
1352	* @return Reference to this string.
1353	*/
1354	basic_string&
1355	assign(const basic_string& __str)
1356	{
1357	#if __cplusplus >= 201103L
1358	if (_Alloc_traits::_S_propagate_on_copy_assign())
1359	{
1360	if (!_Alloc_traits::_S_always_equal() && !_M_is_local()
1361	&& _M_get_allocator() != __str._M_get_allocator())
1362	{
1363	// Propagating allocator cannot free existing storage so must
1364	// deallocate it before replacing current allocator.
1365	if (__str.size() <= _S_local_capacity)
1366	{
1367	_M_destroy(_M_allocated_capacity);
1368	_M_data(_M_local_data());
1369	_M_set_length(`0`);
1370	}
1371	else
1372	{
1373	const auto __len = __str.size();
1374	auto __alloc = __str._M_get_allocator();
1375	// If this allocation throws there are no effects:
1376	auto __ptr = _Alloc_traits::allocate(__alloc, __len + `1`);
1377	_M_destroy(_M_allocated_capacity);
1378	_M_data(__ptr);
1379	_M_capacity(__len);
1380	_M_set_length(__len);
1381	}
1382	}
1383	std::__alloc_on_copy(_M_get_allocator(), __str._M_get_allocator());
1384	}
1385	#endif
1386	this->_M_assign(__str);
1387	return *this;
1388	}
1389
1390	#if __cplusplus >= 201103L
1391	/**
1392	* @brief Set value to contents of another string.
1393	* @param __str Source string to use.
1394	* @return Reference to this string.
1395	*
1396	* This function sets this string to the exact contents of @a __str.
1397	* @a __str is a valid, but unspecified string.
1398	*/
1399	basic_string&
1400	assign(basic_string&& __str)
1401	noexcept(_Alloc_traits::_S_nothrow_move())
1402	{
1403	// _GLIBCXX_RESOLVE_LIB_DEFECTS
1404	// 2063. Contradictory requirements for string move assignment
1405	return *this = std::move(__str);
1406	}
1407	#endif // C++11
1408
1409	/**
1410	* @brief Set value to a substring of a string.
1411	* @param __str The string to use.
1412	* @param __pos Index of the first character of str.
1413	* @param __n Number of characters to use.
1414	* @return Reference to this string.
1415	* @throw std::out_of_range if @a pos is not a valid index.
1416	*
1417	* This function sets this string to the substring of @a __str
1418	* consisting of @a __n characters at @a __pos. If @a __n is
1419	* is larger than the number of available characters in @a
1420	* __str, the remainder of @a __str is used.
1421	*/
1422	basic_string&
1423	assign(const basic_string& __str, size_type __pos, size_type __n = npos)
1424	{ return _M_replace(size_type(`0`), this->size(), __str._M_data()
1425	+ __str._M_check(__pos, "basic_string::assign"),
1426	__str._M_limit(__pos, __n)); }
1427
1428	/**
1429	* @brief Set value to a C substring.
1430	* @param __s The C string to use.
1431	* @param __n Number of characters to use.
1432	* @return Reference to this string.
1433	*
1434	* This function sets the value of this string to the first @a __n
1435	* characters of @a __s. If @a __n is is larger than the number of
1436	* available characters in @a __s, the remainder of @a __s is used.
1437	*/
1438	basic_string&
1439	assign(const _CharT* __s, size_type __n)
1440	{
1441	__glibcxx_requires_string_len(__s, __n);
1442	return _M_replace(size_type(`0`), this->size(), __s, __n);
1443	}
1444
1445	/**
1446	* @brief Set value to contents of a C string.
1447	* @param __s The C string to use.
1448	* @return Reference to this string.
1449	*
1450	* This function sets the value of this string to the value of @a __s.
1451	* The data is copied, so there is no dependence on @a __s once the
1452	* function returns.
1453	*/
1454	basic_string&
1455	assign(const _CharT* __s)
1456	{
1457	__glibcxx_requires_string(__s);
1458	return _M_replace(size_type(`0`), this->size(), __s,
1459	traits_type::length(__s));
1460	}
1461
1462	/**
1463	* @brief Set value to multiple characters.
1464	* @param __n Length of the resulting string.
1465	* @param __c The character to use.
1466	* @return Reference to this string.
1467	*
1468	* This function sets the value of this string to @a __n copies of
1469	* character @a __c.
1470	*/
1471	basic_string&
1472	assign(size_type __n, _CharT __c)
1473	{ return _M_replace_aux(size_type(`0`), this->size(), __n, __c); }
1474
1475	/**
1476	* @brief Set value to a range of characters.
1477	* @param __first Iterator referencing the first character to append.
1478	* @param __last Iterator marking the end of the range.
1479	* @return Reference to this string.
1480	*
1481	* Sets value of string to characters in the range [__first,__last).
1482	*/
1483	#if __cplusplus >= 201103L
1484	template<class _InputIterator,
1485	typename = std::_RequireInputIter<_InputIterator>>
1486	#else
1487	template<class _InputIterator>
1488	#endif
1489	basic_string&
1490	assign(_InputIterator __first, _InputIterator __last)
1491	{ return this->replace(begin(), end(), __first, __last); }
1492
1493	#if __cplusplus >= 201103L
1494	/**
1495	* @brief Set value to an initializer_list of characters.
1496	* @param __l The initializer_list of characters to assign.
1497	* @return Reference to this string.
1498	*/
1499	basic_string&
1500	assign(initializer_list<_CharT> __l)
1501	{ return this->assign(__l.begin(), __l.size()); }
1502	#endif // C++11
1503
1504	#if __cplusplus >= 201703L
1505	/**
1506	* @brief Set value from a string_view.
1507	* @param __svt The source object convertible to string_view.
1508	* @return Reference to this string.
1509	*/
1510	template<typename _Tp>
1511	_If_sv<_Tp, basic_string&>
1512	assign(const _Tp& __svt)
1513	{
1514	__sv_type __sv = __svt;
1515	return this->assign(__sv.data(), __sv.size());
1516	}
1517
1518	/**
1519	* @brief Set value from a range of characters in a string_view.
1520	* @param __svt The source object convertible to string_view.
1521	* @param __pos The position in the string_view to assign from.
1522	* @param __n The number of characters to assign.
1523	* @return Reference to this string.
1524	*/
1525	template<typename _Tp>
1526	_If_sv<_Tp, basic_string&>
1527	assign(const _Tp& __svt, size_type __pos, size_type __n = npos)
1528	{
1529	__sv_type __sv = __svt;
1530	return _M_replace(size_type(`0`), this->size(),
1531	__sv.data()
1532	+ std::__sv_check(__sv.size(), __pos, "basic_string::assign"),
1533	std::__sv_limit(__sv.size(), __pos, __n));
1534	}
1535	#endif // C++17
1536
1537	#if __cplusplus >= 201103L
1538	/**
1539	* @brief Insert multiple characters.
1540	* @param __p Const_iterator referencing location in string to
1541	* insert at.
1542	* @param __n Number of characters to insert
1543	* @param __c The character to insert.
1544	* @return Iterator referencing the first inserted char.
1545	* @throw std::length_error If new length exceeds @c max_size().
1546	*
1547	* Inserts @a __n copies of character @a __c starting at the
1548	* position referenced by iterator @a __p. If adding
1549	* characters causes the length to exceed max_size(),
1550	* length_error is thrown. The value of the string doesn't
1551	* change if an error is thrown.
1552	*/
1553	iterator
1554	insert(const_iterator __p, size_type __n, _CharT __c)
1555	{
1556	_GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
1557	const size_type __pos = __p - begin();
1558	this->replace(__p, __p, __n, __c);
1559	return iterator(this->_M_data() + __pos);
1560	}
1561	#else
1562	/**
1563	* @brief Insert multiple characters.
1564	* @param __p Iterator referencing location in string to insert at.
1565	* @param __n Number of characters to insert
1566	* @param __c The character to insert.
1567	* @throw std::length_error If new length exceeds @c max_size().
1568	*
1569	* Inserts @a __n copies of character @a __c starting at the
1570	* position referenced by iterator @a __p. If adding
1571	* characters causes the length to exceed max_size(),
1572	* length_error is thrown. The value of the string doesn't
1573	* change if an error is thrown.
1574	*/
1575	void
1576	insert(iterator __p, size_type __n, _CharT __c)
1577	{ this->replace(__p, __p, __n, __c); }
1578	#endif
1579
1580	#if __cplusplus >= 201103L
1581	/**
1582	* @brief Insert a range of characters.
1583	* @param __p Const_iterator referencing location in string to
1584	* insert at.
1585	* @param __beg Start of range.
1586	* @param __end End of range.
1587	* @return Iterator referencing the first inserted char.
1588	* @throw std::length_error If new length exceeds @c max_size().
1589	*
1590	* Inserts characters in range [beg,end). If adding characters
1591	* causes the length to exceed max_size(), length_error is
1592	* thrown. The value of the string doesn't change if an error
1593	* is thrown.
1594	*/
1595	template<class _InputIterator,
1596	typename = std::_RequireInputIter<_InputIterator>>
1597	iterator
1598	insert(const_iterator __p, _InputIterator __beg, _InputIterator __end)
1599	{
1600	_GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
1601	const size_type __pos = __p - begin();
1602	this->replace(__p, __p, __beg, __end);
1603	return iterator(this->_M_data() + __pos);
1604	}
1605	#else
1606	/**
1607	* @brief Insert a range of characters.
1608	* @param __p Iterator referencing location in string to insert at.
1609	* @param __beg Start of range.
1610	* @param __end End of range.
1611	* @throw std::length_error If new length exceeds @c max_size().
1612	*
1613	* Inserts characters in range [__beg,__end). If adding
1614	* characters causes the length to exceed max_size(),
1615	* length_error is thrown. The value of the string doesn't
1616	* change if an error is thrown.
1617	*/
1618	template<class _InputIterator>
1619	void
1620	insert(iterator __p, _InputIterator __beg, _InputIterator __end)
1621	{ this->replace(__p, __p, __beg, __end); }
1622	#endif
1623
1624	#if __cplusplus >= 201103L
1625	/**
1626	* @brief Insert an initializer_list of characters.
1627	* @param __p Iterator referencing location in string to insert at.
1628	* @param __l The initializer_list of characters to insert.
1629	* @throw std::length_error If new length exceeds @c max_size().
1630	*/
1631	iterator
1632	insert(const_iterator __p, initializer_list<_CharT> __l)
1633	{ return this->insert(__p, __l.begin(), __l.end()); }
1634
1635	#ifdef _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
1636	// See PR libstdc++/83328
1637	void
1638	insert(iterator __p, initializer_list<_CharT> __l)
1639	{
1640	_GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
1641	this->insert(__p - begin(), __l.begin(), __l.size());
1642	}
1643	#endif
1644	#endif // C++11
1645
1646	/**
1647	* @brief Insert value of a string.
1648	* @param __pos1 Position in string to insert at.
1649	* @param __str The string to insert.
1650	* @return Reference to this string.
1651	* @throw std::length_error If new length exceeds @c max_size().
1652	*
1653	* Inserts value of @a __str starting at @a __pos1. If adding
1654	* characters causes the length to exceed max_size(),
1655	* length_error is thrown. The value of the string doesn't
1656	* change if an error is thrown.
1657	*/
1658	basic_string&
1659	insert(size_type __pos1, const basic_string& __str)
1660	{ return this->replace(__pos1, size_type(`0`),
1661	__str._M_data(), __str.size()); }
1662
1663	/**
1664	* @brief Insert a substring.
1665	* @param __pos1 Position in string to insert at.
1666	* @param __str The string to insert.
1667	* @param __pos2 Start of characters in str to insert.
1668	* @param __n Number of characters to insert.
1669	* @return Reference to this string.
1670	* @throw std::length_error If new length exceeds @c max_size().
1671	* @throw std::out_of_range If @a pos1 > size() or
1672	* @a __pos2 > @a str.size().
1673	*
1674	* Starting at @a pos1, insert @a __n character of @a __str
1675	* beginning with @a __pos2. If adding characters causes the
1676	* length to exceed max_size(), length_error is thrown. If @a
1677	* __pos1 is beyond the end of this string or @a __pos2 is
1678	* beyond the end of @a __str, out_of_range is thrown. The
1679	* value of the string doesn't change if an error is thrown.
1680	*/
1681	basic_string&
1682	insert(size_type __pos1, const basic_string& __str,
1683	size_type __pos2, size_type __n = npos)
1684	{ return this->replace(__pos1, size_type(`0`), __str._M_data()
1685	+ __str._M_check(__pos2, "basic_string::insert"),
1686	__str._M_limit(__pos2, __n)); }
1687
1688	/**
1689	* @brief Insert a C substring.
1690	* @param __pos Position in string to insert at.
1691	* @param __s The C string to insert.
1692	* @param __n The number of characters to insert.
1693	* @return Reference to this string.
1694	* @throw std::length_error If new length exceeds @c max_size().
1695	* @throw std::out_of_range If @a __pos is beyond the end of this
1696	* string.
1697	*
1698	* Inserts the first @a __n characters of @a __s starting at @a
1699	* __pos. If adding characters causes the length to exceed
1700	* max_size(), length_error is thrown. If @a __pos is beyond
1701	* end(), out_of_range is thrown. The value of the string
1702	* doesn't change if an error is thrown.
1703	*/
1704	basic_string&
1705	insert(size_type __pos, const _CharT* __s, size_type __n)
1706	{ return this->replace(__pos, size_type(`0`), __s, __n); }
1707
1708	/**
1709	* @brief Insert a C string.
1710	* @param __pos Position in string to insert at.
1711	* @param __s The C string to insert.
1712	* @return Reference to this string.
1713	* @throw std::length_error If new length exceeds @c max_size().
1714	* @throw std::out_of_range If @a pos is beyond the end of this
1715	* string.
1716	*
1717	* Inserts the first @a n characters of @a __s starting at @a __pos. If
1718	* adding characters causes the length to exceed max_size(),
1719	* length_error is thrown. If @a __pos is beyond end(), out_of_range is
1720	* thrown. The value of the string doesn't change if an error is
1721	* thrown.
1722	*/
1723	basic_string&
1724	insert(size_type __pos, const _CharT* __s)
1725	{
1726	__glibcxx_requires_string(__s);
1727	return this->replace(__pos, size_type(`0`), __s,
1728	traits_type::length(__s));
1729	}
1730
1731	/**
1732	* @brief Insert multiple characters.
1733	* @param __pos Index in string to insert at.
1734	* @param __n Number of characters to insert
1735	* @param __c The character to insert.
1736	* @return Reference to this string.
1737	* @throw std::length_error If new length exceeds @c max_size().
1738	* @throw std::out_of_range If @a __pos is beyond the end of this
1739	* string.
1740	*
1741	* Inserts @a __n copies of character @a __c starting at index
1742	* @a __pos. If adding characters causes the length to exceed
1743	* max_size(), length_error is thrown. If @a __pos > length(),
1744	* out_of_range is thrown. The value of the string doesn't
1745	* change if an error is thrown.
1746	*/
1747	basic_string&
1748	insert(size_type __pos, size_type __n, _CharT __c)
1749	{ return _M_replace_aux(_M_check(__pos, "basic_string::insert"),
1750	size_type(`0`), __n, __c); }
1751
1752	/**
1753	* @brief Insert one character.
1754	* @param __p Iterator referencing position in string to insert at.
1755	* @param __c The character to insert.
1756	* @return Iterator referencing newly inserted char.
1757	* @throw std::length_error If new length exceeds @c max_size().
1758	*
1759	* Inserts character @a __c at position referenced by @a __p.
1760	* If adding character causes the length to exceed max_size(),
1761	* length_error is thrown. If @a __p is beyond end of string,
1762	* out_of_range is thrown. The value of the string doesn't
1763	* change if an error is thrown.
1764	*/
1765	iterator
1766	insert(__const_iterator __p, _CharT __c)
1767	{
1768	_GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
1769	const size_type __pos = __p - begin();
1770	_M_replace_aux(__pos, size_type(`0`), size_type(`1`), __c);
1771	return iterator(_M_data() + __pos);
1772	}
1773
1774	#if __cplusplus >= 201703L
1775	/**
1776	* @brief Insert a string_view.
1777	* @param __pos Position in string to insert at.
1778	* @param __svt The object convertible to string_view to insert.
1779	* @return Reference to this string.
1780	*/
1781	template<typename _Tp>
1782	_If_sv<_Tp, basic_string&>
1783	insert(size_type __pos, const _Tp& __svt)
1784	{
1785	__sv_type __sv = __svt;
1786	return this->insert(__pos, __sv.data(), __sv.size());
1787	}
1788
1789	/**
1790	* @brief Insert a string_view.
1791	* @param __pos1 Position in string to insert at.
1792	* @param __svt The object convertible to string_view to insert from.
1793	* @param __pos2 Start of characters in str to insert.
1794	* @param __n The number of characters to insert.
1795	* @return Reference to this string.
1796	*/
1797	template<typename _Tp>
1798	_If_sv<_Tp, basic_string&>
1799	insert(size_type __pos1, const _Tp& __svt,
1800	size_type __pos2, size_type __n = npos)
1801	{
1802	__sv_type __sv = __svt;
1803	return this->replace(__pos1, size_type(`0`),
1804	__sv.data()
1805	+ std::__sv_check(__sv.size(), __pos2, "basic_string::insert"),
1806	std::__sv_limit(__sv.size(), __pos2, __n));
1807	}
1808	#endif // C++17
1809
1810	/**
1811	* @brief Remove characters.
1812	* @param __pos Index of first character to remove (default 0).
1813	* @param __n Number of characters to remove (default remainder).
1814	* @return Reference to this string.
1815	* @throw std::out_of_range If @a pos is beyond the end of this
1816	* string.
1817	*
1818	* Removes @a __n characters from this string starting at @a
1819	* __pos. The length of the string is reduced by @a __n. If
1820	* there are < @a __n characters to remove, the remainder of
1821	* the string is truncated. If @a __p is beyond end of string,
1822	* out_of_range is thrown. The value of the string doesn't
1823	* change if an error is thrown.
1824	*/
1825	basic_string&
1826	erase(size_type __pos = `0`, size_type __n = npos)
1827	{
1828	_M_check(__pos, "basic_string::erase");
1829	if (__n == npos)
1830	this->_M_set_length(__pos);
1831	else if (__n != `0`)
1832	this->_M_erase(__pos, _M_limit(__pos, __n));
1833	return *this;
1834	}
1835
1836	/**
1837	* @brief Remove one character.
1838	* @param __position Iterator referencing the character to remove.
1839	* @return iterator referencing same location after removal.
1840	*
1841	* Removes the character at @a __position from this string. The value
1842	* of the string doesn't change if an error is thrown.
1843	*/
1844	iterator
1845	erase(__const_iterator __position)
1846	{
1847	_GLIBCXX_DEBUG_PEDASSERT(__position >= begin()
1848	&& __position < end());
1849	const size_type __pos = __position - begin();
1850	this->_M_erase(__pos, size_type(`1`));
1851	return iterator(_M_data() + __pos);
1852	}
1853
1854	/**
1855	* @brief Remove a range of characters.
1856	* @param __first Iterator referencing the first character to remove.
1857	* @param __last Iterator referencing the end of the range.
1858	* @return Iterator referencing location of first after removal.
1859	*
1860	* Removes the characters in the range [first,last) from this string.
1861	* The value of the string doesn't change if an error is thrown.
1862	*/
1863	iterator
1864	erase(__const_iterator __first, __const_iterator __last)
1865	{
1866	_GLIBCXX_DEBUG_PEDASSERT(__first >= begin() && __first <= __last
1867	&& __last <= end());
1868	const size_type __pos = __first - begin();
1869	if (__last == end())
1870	this->_M_set_length(__pos);
1871	else
1872	this->_M_erase(__pos, __last - __first);
1873	return iterator(this->_M_data() + __pos);
1874	}
1875
1876	#if __cplusplus >= 201103L
1877	/**
1878	* @brief Remove the last character.
1879	*
1880	* The string must be non-empty.
1881	*/
1882	void
1883	pop_back() noexcept
1884	{
1885	__glibcxx_assert(!empty());
1886	_M_erase(size() - `1`, `1`);
1887	}
1888	#endif // C++11
1889
1890	/**
1891	* @brief Replace characters with value from another string.
1892	* @param __pos Index of first character to replace.
1893	* @param __n Number of characters to be replaced.
1894	* @param __str String to insert.
1895	* @return Reference to this string.
1896	* @throw std::out_of_range If @a pos is beyond the end of this
1897	* string.
1898	* @throw std::length_error If new length exceeds @c max_size().
1899	*
1900	* Removes the characters in the range [__pos,__pos+__n) from
1901	* this string. In place, the value of @a __str is inserted.
1902	* If @a __pos is beyond end of string, out_of_range is thrown.
1903	* If the length of the result exceeds max_size(), length_error
1904	* is thrown. The value of the string doesn't change if an
1905	* error is thrown.
1906	*/
1907	basic_string&
1908	replace(size_type __pos, size_type __n, const basic_string& __str)
1909	{ return this->replace(__pos, __n, __str._M_data(), __str.size()); }
1910
1911	/**
1912	* @brief Replace characters with value from another string.
1913	* @param __pos1 Index of first character to replace.
1914	* @param __n1 Number of characters to be replaced.
1915	* @param __str String to insert.
1916	* @param __pos2 Index of first character of str to use.
1917	* @param __n2 Number of characters from str to use.
1918	* @return Reference to this string.
1919	* @throw std::out_of_range If @a __pos1 > size() or @a __pos2 >
1920	* __str.size().
1921	* @throw std::length_error If new length exceeds @c max_size().
1922	*
1923	* Removes the characters in the range [__pos1,__pos1 + n) from this
1924	* string. In place, the value of @a __str is inserted. If @a __pos is
1925	* beyond end of string, out_of_range is thrown. If the length of the
1926	* result exceeds max_size(), length_error is thrown. The value of the
1927	* string doesn't change if an error is thrown.
1928	*/
1929	basic_string&
1930	replace(size_type __pos1, size_type __n1, const basic_string& __str,
1931	size_type __pos2, size_type __n2 = npos)
1932	{ return this->replace(__pos1, __n1, __str._M_data()
1933	+ __str._M_check(__pos2, "basic_string::replace"),
1934	__str._M_limit(__pos2, __n2)); }
1935
1936	/**
1937	* @brief Replace characters with value of a C substring.
1938	* @param __pos Index of first character to replace.
1939	* @param __n1 Number of characters to be replaced.
1940	* @param __s C string to insert.
1941	* @param __n2 Number of characters from @a s to use.
1942	* @return Reference to this string.
1943	* @throw std::out_of_range If @a pos1 > size().
1944	* @throw std::length_error If new length exceeds @c max_size().
1945	*
1946	* Removes the characters in the range [__pos,__pos + __n1)
1947	* from this string. In place, the first @a __n2 characters of
1948	* @a __s are inserted, or all of @a __s if @a __n2 is too large. If
1949	* @a __pos is beyond end of string, out_of_range is thrown. If
1950	* the length of result exceeds max_size(), length_error is
1951	* thrown. The value of the string doesn't change if an error
1952	* is thrown.
1953	*/
1954	basic_string&
1955	replace(size_type __pos, size_type __n1, const _CharT* __s,
1956	size_type __n2)
1957	{
1958	__glibcxx_requires_string_len(__s, __n2);
1959	return _M_replace(_M_check(__pos, "basic_string::replace"),
1960	_M_limit(__pos, __n1), __s, __n2);
1961	}
1962
1963	/**
1964	* @brief Replace characters with value of a C string.
1965	* @param __pos Index of first character to replace.
1966	* @param __n1 Number of characters to be replaced.
1967	* @param __s C string to insert.
1968	* @return Reference to this string.
1969	* @throw std::out_of_range If @a pos > size().
1970	* @throw std::length_error If new length exceeds @c max_size().
1971	*
1972	* Removes the characters in the range [__pos,__pos + __n1)
1973	* from this string. In place, the characters of @a __s are
1974	* inserted. If @a __pos is beyond end of string, out_of_range
1975	* is thrown. If the length of result exceeds max_size(),
1976	* length_error is thrown. The value of the string doesn't
1977	* change if an error is thrown.
1978	*/
1979	basic_string&
1980	replace(size_type __pos, size_type __n1, const _CharT* __s)
1981	{
1982	__glibcxx_requires_string(__s);
1983	return this->replace(__pos, __n1, __s, traits_type::length(__s));
1984	}
1985
1986	/**
1987	* @brief Replace characters with multiple characters.
1988	* @param __pos Index of first character to replace.
1989	* @param __n1 Number of characters to be replaced.
1990	* @param __n2 Number of characters to insert.
1991	* @param __c Character to insert.
1992	* @return Reference to this string.
1993	* @throw std::out_of_range If @a __pos > size().
1994	* @throw std::length_error If new length exceeds @c max_size().
1995	*
1996	* Removes the characters in the range [pos,pos + n1) from this
1997	* string. In place, @a __n2 copies of @a __c are inserted.
1998	* If @a __pos is beyond end of string, out_of_range is thrown.
1999	* If the length of result exceeds max_size(), length_error is
2000	* thrown. The value of the string doesn't change if an error
2001	* is thrown.
2002	*/
2003	basic_string&
2004	replace(size_type __pos, size_type __n1, size_type __n2, _CharT __c)
2005	{ return _M_replace_aux(_M_check(__pos, "basic_string::replace"),
2006	_M_limit(__pos, __n1), __n2, __c); }
2007
2008	/**
2009	* @brief Replace range of characters with string.
2010	* @param __i1 Iterator referencing start of range to replace.
2011	* @param __i2 Iterator referencing end of range to replace.
2012	* @param __str String value to insert.
2013	* @return Reference to this string.
2014	* @throw std::length_error If new length exceeds @c max_size().
2015	*
2016	* Removes the characters in the range [__i1,__i2). In place,
2017	* the value of @a __str is inserted. If the length of result
2018	* exceeds max_size(), length_error is thrown. The value of
2019	* the string doesn't change if an error is thrown.
2020	*/
2021	basic_string&
2022	replace(__const_iterator __i1, __const_iterator __i2,
2023	const basic_string& __str)
2024	{ return this->replace(__i1, __i2, __str._M_data(), __str.size()); }
2025
2026	/**
2027	* @brief Replace range of characters with C substring.
2028	* @param __i1 Iterator referencing start of range to replace.
2029	* @param __i2 Iterator referencing end of range to replace.
2030	* @param __s C string value to insert.
2031	* @param __n Number of characters from s to insert.
2032	* @return Reference to this string.
2033	* @throw std::length_error If new length exceeds @c max_size().
2034	*
2035	* Removes the characters in the range [__i1,__i2). In place,
2036	* the first @a __n characters of @a __s are inserted. If the
2037	* length of result exceeds max_size(), length_error is thrown.
2038	* The value of the string doesn't change if an error is
2039	* thrown.
2040	*/
2041	basic_string&
2042	replace(__const_iterator __i1, __const_iterator __i2,
2043	const _CharT* __s, size_type __n)
2044	{
2045	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2046	&& __i2 <= end());
2047	return this->replace(__i1 - begin(), __i2 - __i1, __s, __n);
2048	}
2049
2050	/**
2051	* @brief Replace range of characters with C string.
2052	* @param __i1 Iterator referencing start of range to replace.
2053	* @param __i2 Iterator referencing end of range to replace.
2054	* @param __s C string value to insert.
2055	* @return Reference to this string.
2056	* @throw std::length_error If new length exceeds @c max_size().
2057	*
2058	* Removes the characters in the range [__i1,__i2). In place,
2059	* the characters of @a __s are inserted. If the length of
2060	* result exceeds max_size(), length_error is thrown. The
2061	* value of the string doesn't change if an error is thrown.
2062	*/
2063	basic_string&
2064	replace(__const_iterator __i1, __const_iterator __i2, const _CharT* __s)
2065	{
2066	__glibcxx_requires_string(__s);
2067	return this->replace(__i1, __i2, __s, traits_type::length(__s));
2068	}
2069
2070	/**
2071	* @brief Replace range of characters with multiple characters
2072	* @param __i1 Iterator referencing start of range to replace.
2073	* @param __i2 Iterator referencing end of range to replace.
2074	* @param __n Number of characters to insert.
2075	* @param __c Character to insert.
2076	* @return Reference to this string.
2077	* @throw std::length_error If new length exceeds @c max_size().
2078	*
2079	* Removes the characters in the range [__i1,__i2). In place,
2080	* @a __n copies of @a __c are inserted. If the length of
2081	* result exceeds max_size(), length_error is thrown. The
2082	* value of the string doesn't change if an error is thrown.
2083	*/
2084	basic_string&
2085	replace(__const_iterator __i1, __const_iterator __i2, size_type __n,
2086	_CharT __c)
2087	{
2088	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2089	&& __i2 <= end());
2090	return _M_replace_aux(__i1 - begin(), __i2 - __i1, __n, __c);
2091	}
2092
2093	/**
2094	* @brief Replace range of characters with range.
2095	* @param __i1 Iterator referencing start of range to replace.
2096	* @param __i2 Iterator referencing end of range to replace.
2097	* @param __k1 Iterator referencing start of range to insert.
2098	* @param __k2 Iterator referencing end of range to insert.
2099	* @return Reference to this string.
2100	* @throw std::length_error If new length exceeds @c max_size().
2101	*
2102	* Removes the characters in the range [__i1,__i2). In place,
2103	* characters in the range [__k1,__k2) are inserted. If the
2104	* length of result exceeds max_size(), length_error is thrown.
2105	* The value of the string doesn't change if an error is
2106	* thrown.
2107	*/
2108	#if __cplusplus >= 201103L
2109	template<class _InputIterator,
2110	typename = std::_RequireInputIter<_InputIterator>>
2111	basic_string&
2112	replace(const_iterator __i1, const_iterator __i2,
2113	_InputIterator __k1, _InputIterator __k2)
2114	{
2115	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2116	&& __i2 <= end());
2117	__glibcxx_requires_valid_range(__k1, __k2);
2118	return this->_M_replace_dispatch(__i1, __i2, __k1, __k2,
2119	std::__false_type ());
2120	}
2121	#else
2122	template<class _InputIterator>
2123	#ifdef _GLIBCXX_DISAMBIGUATE_REPLACE_INST
2124	typename __enable_if_not_native_iterator<_InputIterator>::__type
2125	#else
2126	basic_string&
2127	#endif
2128	replace(iterator __i1, iterator __i2,
2129	_InputIterator __k1, _InputIterator __k2)
2130	{
2131	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2132	&& __i2 <= end());
2133	__glibcxx_requires_valid_range(__k1, __k2);
2134	typedef typename std::__is_integer<_InputIterator>::__type _Integral;
2135	return _M_replace_dispatch(__i1, __i2, __k1, __k2, _Integral());
2136	}
2137	#endif
2138
2139	// Specializations for the common case of pointer and iterator:
2140	// useful to avoid the overhead of temporary buffering in _M_replace.
2141	basic_string&
2142	replace(__const_iterator __i1, __const_iterator __i2,
2143	_CharT* __k1, _CharT* __k2)
2144	{
2145	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2146	&& __i2 <= end());
2147	__glibcxx_requires_valid_range(__k1, __k2);
2148	return this->replace(__i1 - begin(), __i2 - __i1,
2149	__k1, __k2 - __k1);
2150	}
2151
2152	basic_string&
2153	replace(__const_iterator __i1, __const_iterator __i2,
2154	const _CharT* __k1, const _CharT* __k2)
2155	{
2156	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2157	&& __i2 <= end());
2158	__glibcxx_requires_valid_range(__k1, __k2);
2159	return this->replace(__i1 - begin(), __i2 - __i1,
2160	__k1, __k2 - __k1);
2161	}
2162
2163	basic_string&
2164	replace(__const_iterator __i1, __const_iterator __i2,
2165	iterator __k1, iterator __k2)
2166	{
2167	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2168	&& __i2 <= end());
2169	__glibcxx_requires_valid_range(__k1, __k2);
2170	return this->replace(__i1 - begin(), __i2 - __i1,
2171	__k1.base(), __k2 - __k1);
2172	}
2173
2174	basic_string&
2175	replace(__const_iterator __i1, __const_iterator __i2,
2176	const_iterator __k1, const_iterator __k2)
2177	{
2178	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2179	&& __i2 <= end());
2180	__glibcxx_requires_valid_range(__k1, __k2);
2181	return this->replace(__i1 - begin(), __i2 - __i1,
2182	__k1.base(), __k2 - __k1);
2183	}
2184
2185	#if __cplusplus >= 201103L
2186	/**
2187	* @brief Replace range of characters with initializer_list.
2188	* @param __i1 Iterator referencing start of range to replace.
2189	* @param __i2 Iterator referencing end of range to replace.
2190	* @param __l The initializer_list of characters to insert.
2191	* @return Reference to this string.
2192	* @throw std::length_error If new length exceeds @c max_size().
2193	*
2194	* Removes the characters in the range [__i1,__i2). In place,
2195	* characters in the range [__k1,__k2) are inserted. If the
2196	* length of result exceeds max_size(), length_error is thrown.
2197	* The value of the string doesn't change if an error is
2198	* thrown.
2199	*/
2200	basic_string& replace(const_iterator __i1, const_iterator __i2,
2201	initializer_list<_CharT> __l)
2202	{ return this->replace(__i1, __i2, __l.begin(), __l.size()); }
2203	#endif // C++11
2204
2205	#if __cplusplus >= 201703L
2206	/**
2207	* @brief Replace range of characters with string_view.
2208	* @param __pos The position to replace at.
2209	* @param __n The number of characters to replace.
2210	* @param __svt The object convertible to string_view to insert.
2211	* @return Reference to this string.
2212	*/
2213	template<typename _Tp>
2214	_If_sv<_Tp, basic_string&>
2215	replace(size_type __pos, size_type __n, const _Tp& __svt)
2216	{
2217	__sv_type __sv = __svt;
2218	return this->replace(__pos, __n, __sv.data(), __sv.size());
2219	}
2220
2221	/**
2222	* @brief Replace range of characters with string_view.
2223	* @param __pos1 The position to replace at.
2224	* @param __n1 The number of characters to replace.
2225	* @param __svt The object convertible to string_view to insert from.
2226	* @param __pos2 The position in the string_view to insert from.
2227	* @param __n2 The number of characters to insert.
2228	* @return Reference to this string.
2229	*/
2230	template<typename _Tp>
2231	_If_sv<_Tp, basic_string&>
2232	replace(size_type __pos1, size_type __n1, const _Tp& __svt,
2233	size_type __pos2, size_type __n2 = npos)
2234	{
2235	__sv_type __sv = __svt;
2236	return this->replace(__pos1, __n1,
2237	__sv.data()
2238	+ std::__sv_check(__sv.size(), __pos2, "basic_string::replace"),
2239	std::__sv_limit(__sv.size(), __pos2, __n2));
2240	}
2241
2242	/**
2243	* @brief Replace range of characters with string_view.
2244	* @param __i1 An iterator referencing the start position
2245	to replace at.
2246	* @param __i2 An iterator referencing the end position
2247	for the replace.
2248	* @param __svt The object convertible to string_view to insert from.
2249	* @return Reference to this string.
2250	*/
2251	template<typename _Tp>
2252	_If_sv<_Tp, basic_string&>
2253	replace(const_iterator __i1, const_iterator __i2, const _Tp& __svt)
2254	{
2255	__sv_type __sv = __svt;
2256	return this->replace(__i1 - begin(), __i2 - __i1, __sv);
2257	}
2258	#endif // C++17
2259
2260	private:
2261	template<class _Integer>
2262	basic_string&
2263	_M_replace_dispatch(const_iterator __i1, const_iterator __i2,
2264	_Integer __n, _Integer __val, __true_type)
2265	{ return _M_replace_aux(__i1 - begin(), __i2 - __i1, __n, __val); }
2266
2267	template<class _InputIterator>
2268	basic_string&
2269	_M_replace_dispatch(const_iterator __i1, const_iterator __i2,
2270	_InputIterator __k1, _InputIterator __k2,
2271	__false_type);
2272
2273	basic_string&
2274	_M_replace_aux(size_type __pos1, size_type __n1, size_type __n2,
2275	_CharT __c);
2276
2277	basic_string&
2278	_M_replace(size_type __pos, size_type __len1, const _CharT* __s,
2279	const size_type __len2);
2280
2281	basic_string&
2282	_M_append(const _CharT* __s, size_type __n);
2283
2284	public:
2285
2286	/**
2287	* @brief Copy substring into C string.
2288	* @param __s C string to copy value into.
2289	* @param __n Number of characters to copy.
2290	* @param __pos Index of first character to copy.
2291	* @return Number of characters actually copied
2292	* @throw std::out_of_range If __pos > size().
2293	*
2294	* Copies up to @a __n characters starting at @a __pos into the
2295	* C string @a __s. If @a __pos is %greater than size(),
2296	* out_of_range is thrown.
2297	*/
2298	size_type
2299	copy(_CharT* __s, size_type __n, size_type __pos = `0`) const;
2300
2301	/**
2302	* @brief Swap contents with another string.
2303	* @param __s String to swap with.
2304	*
2305	* Exchanges the contents of this string with that of @a __s in constant
2306	* time.
2307	*/
2308	void
2309	swap(basic_string& __s) _GLIBCXX_NOEXCEPT;
2310
2311	// String operations:
2312	/**
2313	* @brief Return const pointer to null-terminated contents.
2314	*
2315	* This is a handle to internal data. Do not modify or dire things may
2316	* happen.
2317	*/
2318	const _CharT*
2319	c_str() const _GLIBCXX_NOEXCEPT
2320	{ return _M_data(); }
2321
2322	/**
2323	* @brief Return const pointer to contents.
2324	*
2325	* This is a pointer to internal data. It is undefined to modify
2326	* the contents through the returned pointer. To get a pointer that
2327	* allows modifying the contents use @c &str[0] instead,
2328	* (or in C++17 the non-const @c str.data() overload).
2329	*/
2330	const _CharT*
2331	data() const _GLIBCXX_NOEXCEPT
2332	{ return _M_data(); }
2333
2334	#if __cplusplus >= 201703L
2335	/**
2336	* @brief Return non-const pointer to contents.
2337	*
2338	* This is a pointer to the character sequence held by the string.
2339	* Modifying the characters in the sequence is allowed.
2340	*/
2341	_CharT*
2342	data() noexcept
2343	{ return _M_data(); }
2344	#endif
2345
2346	/**
2347	* @brief Return copy of allocator used to construct this string.
2348	*/
2349	allocator_type
2350	get_allocator() const _GLIBCXX_NOEXCEPT
2351	{ return _M_get_allocator(); }
2352
2353	/**
2354	* @brief Find position of a C substring.
2355	* @param __s C string to locate.
2356	* @param __pos Index of character to search from.
2357	* @param __n Number of characters from @a s to search for.
2358	* @return Index of start of first occurrence.
2359	*
2360	* Starting from @a __pos, searches forward for the first @a
2361	* __n characters in @a __s within this string. If found,
2362	* returns the index where it begins. If not found, returns
2363	* npos.
2364	*/
2365	size_type
2366	find(const _CharT* __s, size_type __pos, size_type __n) const
2367	_GLIBCXX_NOEXCEPT;
2368
2369	/**
2370	* @brief Find position of a string.
2371	* @param __str String to locate.
2372	* @param __pos Index of character to search from (default 0).
2373	* @return Index of start of first occurrence.
2374	*
2375	* Starting from @a __pos, searches forward for value of @a __str within
2376	* this string. If found, returns the index where it begins. If not
2377	* found, returns npos.
2378	*/
2379	size_type
2380	find(const basic_string& __str, size_type __pos = `0`) const
2381	_GLIBCXX_NOEXCEPT
2382	{ return this->find(__str.data(), __pos, __str.size()); }
2383
2384	#if __cplusplus >= 201703L
2385	/**
2386	* @brief Find position of a string_view.
2387	* @param __svt The object convertible to string_view to locate.
2388	* @param __pos Index of character to search from (default 0).
2389	* @return Index of start of first occurrence.
2390	*/
2391	template<typename _Tp>
2392	_If_sv<_Tp, size_type>
2393	find(const _Tp& __svt, size_type __pos = `0`) const
2394	noexcept(is_same<_Tp, __sv_type>::value)
2395	{
2396	__sv_type __sv = __svt;
2397	return this->find(__sv.data(), __pos, __sv.size());
2398	}
2399	#endif // C++17
2400
2401	/**
2402	* @brief Find position of a C string.
2403	* @param __s C string to locate.
2404	* @param __pos Index of character to search from (default 0).
2405	* @return Index of start of first occurrence.
2406	*
2407	* Starting from @a __pos, searches forward for the value of @a
2408	* __s within this string. If found, returns the index where
2409	* it begins. If not found, returns npos.
2410	*/
2411	size_type
2412	find(const _CharT* __s, size_type __pos = `0`) const _GLIBCXX_NOEXCEPT
2413	{
2414	__glibcxx_requires_string(__s);
2415	return this->find(__s, __pos, traits_type::length(__s));
2416	}
2417
2418	/**
2419	* @brief Find position of a character.
2420	* @param __c Character to locate.
2421	* @param __pos Index of character to search from (default 0).
2422	* @return Index of first occurrence.
2423	*
2424	* Starting from @a __pos, searches forward for @a __c within
2425	* this string. If found, returns the index where it was
2426	* found. If not found, returns npos.
2427	*/
2428	size_type
2429	find(_CharT __c, size_type __pos = `0`) const _GLIBCXX_NOEXCEPT;
2430
2431	/**
2432	* @brief Find last position of a string.
2433	* @param __str String to locate.
2434	* @param __pos Index of character to search back from (default end).
2435	* @return Index of start of last occurrence.
2436	*
2437	* Starting from @a __pos, searches backward for value of @a
2438	* __str within this string. If found, returns the index where
2439	* it begins. If not found, returns npos.
2440	*/
2441	size_type
2442	rfind(const basic_string& __str, size_type __pos = npos) const
2443	_GLIBCXX_NOEXCEPT
2444	{ return this->rfind(__str.data(), __pos, __str.size()); }
2445
2446	#if __cplusplus >= 201703L
2447	/**
2448	* @brief Find last position of a string_view.
2449	* @param __svt The object convertible to string_view to locate.
2450	* @param __pos Index of character to search back from (default end).
2451	* @return Index of start of last occurrence.
2452	*/
2453	template<typename _Tp>
2454	_If_sv<_Tp, size_type>
2455	rfind(const _Tp& __svt, size_type __pos = npos) const
2456	noexcept(is_same<_Tp, __sv_type>::value)
2457	{
2458	__sv_type __sv = __svt;
2459	return this->rfind(__sv.data(), __pos, __sv.size());
2460	}
2461	#endif // C++17
2462
2463	/**
2464	* @brief Find last position of a C substring.
2465	* @param __s C string to locate.
2466	* @param __pos Index of character to search back from.
2467	* @param __n Number of characters from s to search for.
2468	* @return Index of start of last occurrence.
2469	*
2470	* Starting from @a __pos, searches backward for the first @a
2471	* __n characters in @a __s within this string. If found,
2472	* returns the index where it begins. If not found, returns
2473	* npos.
2474	*/
2475	size_type
2476	rfind(const _CharT* __s, size_type __pos, size_type __n) const
2477	_GLIBCXX_NOEXCEPT;
2478
2479	/**
2480	* @brief Find last position of a C string.
2481	* @param __s C string to locate.
2482	* @param __pos Index of character to start search at (default end).
2483	* @return Index of start of last occurrence.
2484	*
2485	* Starting from @a __pos, searches backward for the value of
2486	* @a __s within this string. If found, returns the index
2487	* where it begins. If not found, returns npos.
2488	*/
2489	size_type
2490	rfind(const _CharT* __s, size_type __pos = npos) const
2491	{
2492	__glibcxx_requires_string(__s);
2493	return this->rfind(__s, __pos, traits_type::length(__s));
2494	}
2495
2496	/**
2497	* @brief Find last position of a character.
2498	* @param __c Character to locate.
2499	* @param __pos Index of character to search back from (default end).
2500	* @return Index of last occurrence.
2501	*
2502	* Starting from @a __pos, searches backward for @a __c within
2503	* this string. If found, returns the index where it was
2504	* found. If not found, returns npos.
2505	*/
2506	size_type
2507	rfind(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT;
2508
2509	/**
2510	* @brief Find position of a character of string.
2511	* @param __str String containing characters to locate.
2512	* @param __pos Index of character to search from (default 0).
2513	* @return Index of first occurrence.
2514	*
2515	* Starting from @a __pos, searches forward for one of the
2516	* characters of @a __str within this string. If found,
2517	* returns the index where it was found. If not found, returns
2518	* npos.
2519	*/
2520	size_type
2521	find_first_of(const basic_string& __str, size_type __pos = `0`) const
2522	_GLIBCXX_NOEXCEPT
2523	{ return this->find_first_of(__str.data(), __pos, __str.size()); }
2524
2525	#if __cplusplus >= 201703L
2526	/**
2527	* @brief Find position of a character of a string_view.
2528	* @param __svt An object convertible to string_view containing
2529	* characters to locate.
2530	* @param __pos Index of character to search from (default 0).
2531	* @return Index of first occurrence.
2532	*/
2533	template<typename _Tp>
2534	_If_sv<_Tp, size_type>
2535	find_first_of(const _Tp& __svt, size_type __pos = `0`) const
2536	noexcept(is_same<_Tp, __sv_type>::value)
2537	{
2538	__sv_type __sv = __svt;
2539	return this->find_first_of(__sv.data(), __pos, __sv.size());
2540	}
2541	#endif // C++17
2542
2543	/**
2544	* @brief Find position of a character of C substring.
2545	* @param __s String containing characters to locate.
2546	* @param __pos Index of character to search from.
2547	* @param __n Number of characters from s to search for.
2548	* @return Index of first occurrence.
2549	*
2550	* Starting from @a __pos, searches forward for one of the
2551	* first @a __n characters of @a __s within this string. If
2552	* found, returns the index where it was found. If not found,
2553	* returns npos.
2554	*/
2555	size_type
2556	find_first_of(const _CharT* __s, size_type __pos, size_type __n) const
2557	_GLIBCXX_NOEXCEPT;
2558
2559	/**
2560	* @brief Find position of a character of C string.
2561	* @param __s String containing characters to locate.
2562	* @param __pos Index of character to search from (default 0).
2563	* @return Index of first occurrence.
2564	*
2565	* Starting from @a __pos, searches forward for one of the
2566	* characters of @a __s within this string. If found, returns
2567	* the index where it was found. If not found, returns npos.
2568	*/
2569	size_type
2570	find_first_of(const _CharT* __s, size_type __pos = `0`) const
2571	_GLIBCXX_NOEXCEPT
2572	{
2573	__glibcxx_requires_string(__s);
2574	return this->find_first_of(__s, __pos, traits_type::length(__s));
2575	}
2576
2577	/**
2578	* @brief Find position of a character.
2579	* @param __c Character to locate.
2580	* @param __pos Index of character to search from (default 0).
2581	* @return Index of first occurrence.
2582	*
2583	* Starting from @a __pos, searches forward for the character
2584	* @a __c within this string. If found, returns the index
2585	* where it was found. If not found, returns npos.
2586	*
2587	* Note: equivalent to find(__c, __pos).
2588	*/
2589	size_type
2590	find_first_of(_CharT __c, size_type __pos = `0`) const _GLIBCXX_NOEXCEPT
2591	{ return this->find(__c, __pos); }
2592
2593	/**
2594	* @brief Find last position of a character of string.
2595	* @param __str String containing characters to locate.
2596	* @param __pos Index of character to search back from (default end).
2597	* @return Index of last occurrence.
2598	*
2599	* Starting from @a __pos, searches backward for one of the
2600	* characters of @a __str within this string. If found,
2601	* returns the index where it was found. If not found, returns
2602	* npos.
2603	*/
2604	size_type
2605	find_last_of(const basic_string& __str, size_type __pos = npos) const
2606	_GLIBCXX_NOEXCEPT
2607	{ return this->find_last_of(__str.data(), __pos, __str.size()); }
2608
2609	#if __cplusplus >= 201703L
2610	/**
2611	* @brief Find last position of a character of string.
2612	* @param __svt An object convertible to string_view containing
2613	* characters to locate.
2614	* @param __pos Index of character to search back from (default end).
2615	* @return Index of last occurrence.
2616	*/
2617	template<typename _Tp>
2618	_If_sv<_Tp, size_type>
2619	find_last_of(const _Tp& __svt, size_type __pos = npos) const
2620	noexcept(is_same<_Tp, __sv_type>::value)
2621	{
2622	__sv_type __sv = __svt;
2623	return this->find_last_of(__sv.data(), __pos, __sv.size());
2624	}
2625	#endif // C++17
2626
2627	/**
2628	* @brief Find last position of a character of C substring.
2629	* @param __s C string containing characters to locate.
2630	* @param __pos Index of character to search back from.
2631	* @param __n Number of characters from s to search for.
2632	* @return Index of last occurrence.
2633	*
2634	* Starting from @a __pos, searches backward for one of the
2635	* first @a __n characters of @a __s within this string. If
2636	* found, returns the index where it was found. If not found,
2637	* returns npos.
2638	*/
2639	size_type
2640	find_last_of(const _CharT* __s, size_type __pos, size_type __n) const
2641	_GLIBCXX_NOEXCEPT;
2642
2643	/**
2644	* @brief Find last position of a character of C string.
2645	* @param __s C string containing characters to locate.
2646	* @param __pos Index of character to search back from (default end).
2647	* @return Index of last occurrence.
2648	*
2649	* Starting from @a __pos, searches backward for one of the
2650	* characters of @a __s within this string. If found, returns
2651	* the index where it was found. If not found, returns npos.
2652	*/
2653	size_type
2654	find_last_of(const _CharT* __s, size_type __pos = npos) const
2655	_GLIBCXX_NOEXCEPT
2656	{
2657	__glibcxx_requires_string(__s);
2658	return this->find_last_of(__s, __pos, traits_type::length(__s));
2659	}
2660
2661	/**
2662	* @brief Find last position of a character.
2663	* @param __c Character to locate.
2664	* @param __pos Index of character to search back from (default end).
2665	* @return Index of last occurrence.
2666	*
2667	* Starting from @a __pos, searches backward for @a __c within
2668	* this string. If found, returns the index where it was
2669	* found. If not found, returns npos.
2670	*
2671	* Note: equivalent to rfind(__c, __pos).
2672	*/
2673	size_type
2674	find_last_of(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT
2675	{ return this->rfind(__c, __pos); }
2676
2677	/**
2678	* @brief Find position of a character not in string.
2679	* @param __str String containing characters to avoid.
2680	* @param __pos Index of character to search from (default 0).
2681	* @return Index of first occurrence.
2682	*
2683	* Starting from @a __pos, searches forward for a character not contained
2684	* in @a __str within this string. If found, returns the index where it
2685	* was found. If not found, returns npos.
2686	*/
2687	size_type
2688	find_first_not_of(const basic_string& __str, size_type __pos = `0`) const
2689	_GLIBCXX_NOEXCEPT
2690	{ return this->find_first_not_of(__str.data(), __pos, __str.size()); }
2691
2692	#if __cplusplus >= 201703L
2693	/**
2694	* @brief Find position of a character not in a string_view.
2695	* @param __svt A object convertible to string_view containing
2696	* characters to avoid.
2697	* @param __pos Index of character to search from (default 0).
2698	* @return Index of first occurrence.
2699	*/
2700	template<typename _Tp>
2701	_If_sv<_Tp, size_type>
2702	find_first_not_of(const _Tp& __svt, size_type __pos = `0`) const
2703	noexcept(is_same<_Tp, __sv_type>::value)
2704	{
2705	__sv_type __sv = __svt;
2706	return this->find_first_not_of(__sv.data(), __pos, __sv.size());
2707	}
2708	#endif // C++17
2709
2710	/**
2711	* @brief Find position of a character not in C substring.
2712	* @param __s C string containing characters to avoid.
2713	* @param __pos Index of character to search from.
2714	* @param __n Number of characters from __s to consider.
2715	* @return Index of first occurrence.
2716	*
2717	* Starting from @a __pos, searches forward for a character not
2718	* contained in the first @a __n characters of @a __s within
2719	* this string. If found, returns the index where it was
2720	* found. If not found, returns npos.
2721	*/
2722	size_type
2723	find_first_not_of(const _CharT* __s, size_type __pos,
2724	size_type __n) const _GLIBCXX_NOEXCEPT;
2725
2726	/**
2727	* @brief Find position of a character not in C string.
2728	* @param __s C string containing characters to avoid.
2729	* @param __pos Index of character to search from (default 0).
2730	* @return Index of first occurrence.
2731	*
2732	* Starting from @a __pos, searches forward for a character not
2733	* contained in @a __s within this string. If found, returns
2734	* the index where it was found. If not found, returns npos.
2735	*/
2736	size_type
2737	find_first_not_of(const _CharT* __s, size_type __pos = `0`) const
2738	_GLIBCXX_NOEXCEPT
2739	{
2740	__glibcxx_requires_string(__s);
2741	return this->find_first_not_of(__s, __pos, traits_type::length(__s));
2742	}
2743
2744	/**
2745	* @brief Find position of a different character.
2746	* @param __c Character to avoid.
2747	* @param __pos Index of character to search from (default 0).
2748	* @return Index of first occurrence.
2749	*
2750	* Starting from @a __pos, searches forward for a character
2751	* other than @a __c within this string. If found, returns the
2752	* index where it was found. If not found, returns npos.
2753	*/
2754	size_type
2755	find_first_not_of(_CharT __c, size_type __pos = `0`) const
2756	_GLIBCXX_NOEXCEPT;
2757
2758	/**
2759	* @brief Find last position of a character not in string.
2760	* @param __str String containing characters to avoid.
2761	* @param __pos Index of character to search back from (default end).
2762	* @return Index of last occurrence.
2763	*
2764	* Starting from @a __pos, searches backward for a character
2765	* not contained in @a __str within this string. If found,
2766	* returns the index where it was found. If not found, returns
2767	* npos.
2768	*/
2769	size_type
2770	find_last_not_of(const basic_string& __str, size_type __pos = npos) const
2771	_GLIBCXX_NOEXCEPT
2772	{ return this->find_last_not_of(__str.data(), __pos, __str.size()); }
2773
2774	#if __cplusplus >= 201703L
2775	/**
2776	* @brief Find last position of a character not in a string_view.
2777	* @param __svt An object convertible to string_view containing
2778	* characters to avoid.
2779	* @param __pos Index of character to search back from (default end).
2780	* @return Index of last occurrence.
2781	*/
2782	template<typename _Tp>
2783	_If_sv<_Tp, size_type>
2784	find_last_not_of(const _Tp& __svt, size_type __pos = npos) const
2785	noexcept(is_same<_Tp, __sv_type>::value)
2786	{
2787	__sv_type __sv = __svt;
2788	return this->find_last_not_of(__sv.data(), __pos, __sv.size());
2789	}
2790	#endif // C++17
2791
2792	/**
2793	* @brief Find last position of a character not in C substring.
2794	* @param __s C string containing characters to avoid.
2795	* @param __pos Index of character to search back from.
2796	* @param __n Number of characters from s to consider.
2797	* @return Index of last occurrence.
2798	*
2799	* Starting from @a __pos, searches backward for a character not
2800	* contained in the first @a __n characters of @a __s within this string.
2801	* If found, returns the index where it was found. If not found,
2802	* returns npos.
2803	*/
2804	size_type
2805	find_last_not_of(const _CharT* __s, size_type __pos,
2806	size_type __n) const _GLIBCXX_NOEXCEPT;
2807	/**
2808	* @brief Find last position of a character not in C string.
2809	* @param __s C string containing characters to avoid.
2810	* @param __pos Index of character to search back from (default end).
2811	* @return Index of last occurrence.
2812	*
2813	* Starting from @a __pos, searches backward for a character
2814	* not contained in @a __s within this string. If found,
2815	* returns the index where it was found. If not found, returns
2816	* npos.
2817	*/
2818	size_type
2819	find_last_not_of(const _CharT* __s, size_type __pos = npos) const
2820	_GLIBCXX_NOEXCEPT
2821	{
2822	__glibcxx_requires_string(__s);
2823	return this->find_last_not_of(__s, __pos, traits_type::length(__s));
2824	}
2825
2826	/**
2827	* @brief Find last position of a different character.
2828	* @param __c Character to avoid.
2829	* @param __pos Index of character to search back from (default end).
2830	* @return Index of last occurrence.
2831	*
2832	* Starting from @a __pos, searches backward for a character other than
2833	* @a __c within this string. If found, returns the index where it was
2834	* found. If not found, returns npos.
2835	*/
2836	size_type
2837	find_last_not_of(_CharT __c, size_type __pos = npos) const
2838	_GLIBCXX_NOEXCEPT;
2839
2840	/**
2841	* @brief Get a substring.
2842	* @param __pos Index of first character (default 0).
2843	* @param __n Number of characters in substring (default remainder).
2844	* @return The new string.
2845	* @throw std::out_of_range If __pos > size().
2846	*
2847	* Construct and return a new string using the @a __n
2848	* characters starting at @a __pos. If the string is too
2849	* short, use the remainder of the characters. If @a __pos is
2850	* beyond the end of the string, out_of_range is thrown.
2851	*/
2852	basic_string
2853	substr(size_type __pos = `0`, size_type __n = npos) const
2854	{ return basic_string(*this,
2855	_M_check(__pos, "basic_string::substr"), __n); }
2856
2857	/**
2858	* @brief Compare to a string.
2859	* @param __str String to compare against.
2860	* @return Integer < 0, 0, or > 0.
2861	*
2862	* Returns an integer < 0 if this string is ordered before @a
2863	* __str, 0 if their values are equivalent, or > 0 if this
2864	* string is ordered after @a __str. Determines the effective
2865	* length rlen of the strings to compare as the smallest of
2866	* size() and str.size(). The function then compares the two
2867	* strings by calling traits::compare(data(), str.data(),rlen).
2868	* If the result of the comparison is nonzero returns it,
2869	* otherwise the shorter one is ordered first.
2870	*/
2871	int
2872	compare(const basic_string& __str) const
2873	{
2874	const size_type __size = this->size();
2875	const size_type __osize = __str.size();
2876	const size_type __len = std::min(__size, __osize);
2877
2878	int __r = traits_type::compare(_M_data(), __str.data(), __len);
2879	if (!__r)
2880	__r = _S_compare(__size, __osize);
2881	return __r;
2882	}
2883
2884	#if __cplusplus >= 201703L
2885	/**
2886	* @brief Compare to a string_view.
2887	* @param __svt An object convertible to string_view to compare against.
2888	* @return Integer < 0, 0, or > 0.
2889	*/
2890	template<typename _Tp>
2891	_If_sv<_Tp, int>
2892	compare(const _Tp& __svt) const
2893	noexcept(is_same<_Tp, __sv_type>::value)
2894	{
2895	__sv_type __sv = __svt;
2896	const size_type __size = this->size();
2897	const size_type __osize = __sv.size();
2898	const size_type __len = std::min(__size, __osize);
2899
2900	int __r = traits_type::compare(_M_data(), __sv.data(), __len);
2901	if (!__r)
2902	__r = _S_compare(__size, __osize);
2903	return __r;
2904	}
2905
2906	/**
2907	* @brief Compare to a string_view.
2908	* @param __pos A position in the string to start comparing from.
2909	* @param __n The number of characters to compare.
2910	* @param __svt An object convertible to string_view to compare
2911	* against.
2912	* @return Integer < 0, 0, or > 0.
2913	*/
2914	template<typename _Tp>
2915	_If_sv<_Tp, int>
2916	compare(size_type __pos, size_type __n, const _Tp& __svt) const
2917	noexcept(is_same<_Tp, __sv_type>::value)
2918	{
2919	__sv_type __sv = __svt;
2920	return __sv_type(*this).substr(__pos, __n).compare(__sv);
2921	}
2922
2923	/**
2924	* @brief Compare to a string_view.
2925	* @param __pos1 A position in the string to start comparing from.
2926	* @param __n1 The number of characters to compare.
2927	* @param __svt An object convertible to string_view to compare
2928	* against.
2929	* @param __pos2 A position in the string_view to start comparing from.
2930	* @param __n2 The number of characters to compare.
2931	* @return Integer < 0, 0, or > 0.
2932	*/
2933	template<typename _Tp>
2934	_If_sv<_Tp, int>
2935	compare(size_type __pos1, size_type __n1, const _Tp& __svt,
2936	size_type __pos2, size_type __n2 = npos) const
2937	noexcept(is_same<_Tp, __sv_type>::value)
2938	{
2939	__sv_type __sv = __svt;
2940	return __sv_type(*this)
2941	.substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
2942	}
2943	#endif // C++17
2944
2945	/**
2946	* @brief Compare substring to a string.
2947	* @param __pos Index of first character of substring.
2948	* @param __n Number of characters in substring.
2949	* @param __str String to compare against.
2950	* @return Integer < 0, 0, or > 0.
2951	*
2952	* Form the substring of this string from the @a __n characters
2953	* starting at @a __pos. Returns an integer < 0 if the
2954	* substring is ordered before @a __str, 0 if their values are
2955	* equivalent, or > 0 if the substring is ordered after @a
2956	* __str. Determines the effective length rlen of the strings
2957	* to compare as the smallest of the length of the substring
2958	* and @a __str.size(). The function then compares the two
2959	* strings by calling
2960	* traits::compare(substring.data(),str.data(),rlen). If the
2961	* result of the comparison is nonzero returns it, otherwise
2962	* the shorter one is ordered first.
2963	*/
2964	int
2965	compare(size_type __pos, size_type __n, const basic_string& __str) const;
2966
2967	/**
2968	* @brief Compare substring to a substring.
2969	* @param __pos1 Index of first character of substring.
2970	* @param __n1 Number of characters in substring.
2971	* @param __str String to compare against.
2972	* @param __pos2 Index of first character of substring of str.
2973	* @param __n2 Number of characters in substring of str.
2974	* @return Integer < 0, 0, or > 0.
2975	*
2976	* Form the substring of this string from the @a __n1
2977	* characters starting at @a __pos1. Form the substring of @a
2978	* __str from the @a __n2 characters starting at @a __pos2.
2979	* Returns an integer < 0 if this substring is ordered before
2980	* the substring of @a __str, 0 if their values are equivalent,
2981	* or > 0 if this substring is ordered after the substring of
2982	* @a __str. Determines the effective length rlen of the
2983	* strings to compare as the smallest of the lengths of the
2984	* substrings. The function then compares the two strings by
2985	* calling
2986	* traits::compare(substring.data(),str.substr(pos2,n2).data(),rlen).
2987	* If the result of the comparison is nonzero returns it,
2988	* otherwise the shorter one is ordered first.
2989	*/
2990	int
2991	compare(size_type __pos1, size_type __n1, const basic_string& __str,
2992	size_type __pos2, size_type __n2 = npos) const;
2993
2994	/**
2995	* @brief Compare to a C string.
2996	* @param __s C string to compare against.
2997	* @return Integer < 0, 0, or > 0.
2998	*
2999	* Returns an integer < 0 if this string is ordered before @a __s, 0 if
3000	* their values are equivalent, or > 0 if this string is ordered after
3001	* @a __s. Determines the effective length rlen of the strings to
3002	* compare as the smallest of size() and the length of a string
3003	* constructed from @a __s. The function then compares the two strings
3004	* by calling traits::compare(data(),s,rlen). If the result of the
3005	* comparison is nonzero returns it, otherwise the shorter one is
3006	* ordered first.
3007	*/
3008	int
3009	compare(const _CharT* __s) const _GLIBCXX_NOEXCEPT;
3010
3011	// _GLIBCXX_RESOLVE_LIB_DEFECTS
3012	// 5 String::compare specification questionable
3013	/**
3014	* @brief Compare substring to a C string.
3015	* @param __pos Index of first character of substring.
3016	* @param __n1 Number of characters in substring.
3017	* @param __s C string to compare against.
3018	* @return Integer < 0, 0, or > 0.
3019	*
3020	* Form the substring of this string from the @a __n1
3021	* characters starting at @a pos. Returns an integer < 0 if
3022	* the substring is ordered before @a __s, 0 if their values
3023	* are equivalent, or > 0 if the substring is ordered after @a
3024	* __s. Determines the effective length rlen of the strings to
3025	* compare as the smallest of the length of the substring and
3026	* the length of a string constructed from @a __s. The
3027	* function then compares the two string by calling
3028	* traits::compare(substring.data(),__s,rlen). If the result of
3029	* the comparison is nonzero returns it, otherwise the shorter
3030	* one is ordered first.
3031	*/
3032	int
3033	compare(size_type __pos, size_type __n1, const _CharT* __s) const;
3034
3035	/**
3036	* @brief Compare substring against a character %array.
3037	* @param __pos Index of first character of substring.
3038	* @param __n1 Number of characters in substring.
3039	* @param __s character %array to compare against.
3040	* @param __n2 Number of characters of s.
3041	* @return Integer < 0, 0, or > 0.
3042	*
3043	* Form the substring of this string from the @a __n1
3044	* characters starting at @a __pos. Form a string from the
3045	* first @a __n2 characters of @a __s. Returns an integer < 0
3046	* if this substring is ordered before the string from @a __s,
3047	* 0 if their values are equivalent, or > 0 if this substring
3048	* is ordered after the string from @a __s. Determines the
3049	* effective length rlen of the strings to compare as the
3050	* smallest of the length of the substring and @a __n2. The
3051	* function then compares the two strings by calling
3052	* traits::compare(substring.data(),s,rlen). If the result of
3053	* the comparison is nonzero returns it, otherwise the shorter
3054	* one is ordered first.
3055	*
3056	* NB: s must have at least n2 characters, '\\0' has
3057	* no special meaning.
3058	*/
3059	int
3060	compare(size_type __pos, size_type __n1, const _CharT* __s,
3061	size_type __n2) const;
3062
3063	#if __cplusplus > 201703L
3064	bool
3065	starts_with(basic_string_view<_CharT, _Traits> __x) const noexcept
3066	{ return __sv_type(this->data(), this->size()).starts_with(__x); }
3067
3068	bool
3069	starts_with(_CharT __x) const noexcept
3070	{ return __sv_type(this->data(), this->size()).starts_with(__x); }
3071
3072	bool
3073	starts_with(const _CharT* __x) const noexcept
3074	{ return __sv_type(this->data(), this->size()).starts_with(__x); }
3075
3076	bool
3077	ends_with(basic_string_view<_CharT, _Traits> __x) const noexcept
3078	{ return __sv_type(this->data(), this->size()).ends_with(__x); }
3079
3080	bool
3081	ends_with(_CharT __x) const noexcept
3082	{ return __sv_type(this->data(), this->size()).ends_with(__x); }
3083
3084	bool
3085	ends_with(const _CharT* __x) const noexcept
3086	{ return __sv_type(this->data(), this->size()).ends_with(__x); }
3087	#endif // C++20
3088
3089	#if __cplusplus > 202002L
3090	bool
3091	contains(basic_string_view<_CharT, _Traits> __x) const noexcept
3092	{ return __sv_type(this->data(), this->size()).contains(__x); }
3093
3094	bool
3095	contains(_CharT __x) const noexcept
3096	{ return __sv_type(this->data(), this->size()).contains(__x); }
3097
3098	bool
3099	contains(const _CharT* __x) const noexcept
3100	{ return __sv_type(this->data(), this->size()).contains(__x); }
3101	#endif // C++23
3102
3103	// Allow basic_stringbuf::__xfer_bufptrs to call _M_length:
3104	template<typename, typename, typename> friend class basic_stringbuf;
3105	};
3106	_GLIBCXX_END_NAMESPACE_CXX11
3107	#else // !_GLIBCXX_USE_CXX11_ABI
3108	// Reference-counted COW string implentation
3109
3110	/**
3111	* @class basic_string basic_string.h <string>
3112	* @brief Managing sequences of characters and character-like objects.
3113	*
3114	* @ingroup strings
3115	* @ingroup sequences
3116	*
3117	* @tparam _CharT Type of character
3118	* @tparam _Traits Traits for character type, defaults to
3119	* char_traits<_CharT>.
3120	* @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
3121	*
3122	* Meets the requirements of a <a href="tables.html#65">container</a>, a
3123	* <a href="tables.html#66">reversible container</a>, and a
3124	* <a href="tables.html#67">sequence</a>. Of the
3125	* <a href="tables.html#68">optional sequence requirements</a>, only
3126	* @c push_back, @c at, and @c %array access are supported.
3127	*
3128	* @doctodo
3129	*
3130	*
3131	* Documentation? What's that?
3132	* Nathan Myers <ncm@cantrip.org>.
3133	*
3134	* A string looks like this:
3135	*
3136	* @code
3137	* [_Rep]
3138	* _M_length
3139	* [basic_string<char_type>] _M_capacity
3140	* _M_dataplus _M_refcount
3141	* _M_p ----------------> unnamed array of char_type
3142	* @endcode
3143	*
3144	* Where the _M_p points to the first character in the string, and
3145	* you cast it to a pointer-to-_Rep and subtract 1 to get a
3146	* pointer to the header.
3147	*
3148	* This approach has the enormous advantage that a string object
3149	* requires only one allocation. All the ugliness is confined
3150	* within a single %pair of inline functions, which each compile to
3151	* a single @a add instruction: _Rep::_M_data(), and
3152	* string::_M_rep(); and the allocation function which gets a
3153	* block of raw bytes and with room enough and constructs a _Rep
3154	* object at the front.
3155	*
3156	* The reason you want _M_data pointing to the character %array and
3157	* not the _Rep is so that the debugger can see the string
3158	* contents. (Probably we should add a non-inline member to get
3159	* the _Rep for the debugger to use, so users can check the actual
3160	* string length.)
3161	*
3162	* Note that the _Rep object is a POD so that you can have a
3163	* static <em>empty string</em> _Rep object already @a constructed before
3164	* static constructors have run. The reference-count encoding is
3165	* chosen so that a 0 indicates one reference, so you never try to
3166	* destroy the empty-string _Rep object.
3167	*
3168	* All but the last paragraph is considered pretty conventional
3169	* for a C++ string implementation.
3170	*/
3171	// 21.3 Template class basic_string
3172	template<typename _CharT, typename _Traits, typename _Alloc>
3173	class basic_string
3174	{
3175	typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
3176	rebind<_CharT>::other _CharT_alloc_type;
3177	typedef __gnu_cxx::__alloc_traits<_CharT_alloc_type> _CharT_alloc_traits;
3178
3179	// Types:
3180	public:
3181	typedef _Traits traits_type;
3182	typedef typename _Traits::char_type value_type;
3183	typedef _Alloc allocator_type;
3184	typedef typename _CharT_alloc_traits::size_type size_type;
3185	typedef typename _CharT_alloc_traits::difference_type difference_type;
3186	#if __cplusplus < 201103L
3187	typedef typename _CharT_alloc_type::reference reference;
3188	typedef typename _CharT_alloc_type::const_reference const_reference;
3189	#else
3190	typedef value_type& reference;
3191	typedef const value_type& const_reference;
3192	#endif
3193	typedef typename _CharT_alloc_traits::pointer pointer;
3194	typedef typename _CharT_alloc_traits::const_pointer const_pointer;
3195	typedef __gnu_cxx::__normal_iterator<pointer, basic_string> iterator;
3196	typedef __gnu_cxx::__normal_iterator<const_pointer, basic_string>
3197	const_iterator;
3198	typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
3199	typedef std::reverse_iterator<iterator> reverse_iterator;
3200
3201	protected:
3202	// type used for positions in insert, erase etc.
3203	typedef iterator __const_iterator;
3204
3205	private:
3206	// _Rep: string representation
3207	// Invariants:
3208	// 1. String really contains _M_length + 1 characters: due to 21.3.4
3209	// must be kept null-terminated.
3210	// 2. _M_capacity >= _M_length
3211	// Allocated memory is always (_M_capacity + 1) sizeof(_CharT).*
3212	// 3. _M_refcount has three states:
3213	// -1: leaked, one reference, no ref-copies allowed, non-const.
3214	// 0: one reference, non-const.
3215	// n>0: n + 1 references, operations require a lock, const.
3216	// 4. All fields==0 is an empty string, given the extra storage
3217	// beyond-the-end for a null terminator; thus, the shared
3218	// empty string representation needs no constructor.
3219
3220	struct _Rep_base
3221	{
3222	size_type _M_length;
3223	size_type _M_capacity;
3224	_Atomic_word _M_refcount;
3225	};
3226
3227	struct _Rep : _Rep_base
3228	{
3229	// Types:
3230	typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
3231	rebind<char>::other _Raw_bytes_alloc;
3232
3233	// (Public) Data members:
3234
3235	// The maximum number of individual char_type elements of an
3236	// individual string is determined by _S_max_size. This is the
3237	// value that will be returned by max_size(). (Whereas npos
3238	// is the maximum number of bytes the allocator can allocate.)
3239	// If one was to divvy up the theoretical largest size string,
3240	// with a terminating character and m _CharT elements, it'd
3241	// look like this:
3242	// npos = sizeof(_Rep) + (m sizeof(_CharT)) + sizeof(_CharT)*
3243	// Solving for m:
3244	// m = ((npos - sizeof(_Rep))/sizeof(CharT)) - 1
3245	// In addition, this implementation quarters this amount.
3246	static const size_type _S_max_size;
3247	static const _CharT _S_terminal;
3248
3249	// The following storage is init'd to 0 by the linker, resulting
3250	// (carefully) in an empty string with one reference.
3251	static size_type _S_empty_rep_storage[];
3252
3253	static _Rep&
3254	_S_empty_rep() _GLIBCXX_NOEXCEPT
3255	{
3256	// NB: Mild hack to avoid strict-aliasing warnings. Note that
3257	// _S_empty_rep_storage is never modified and the punning should
3258	// be reasonably safe in this case.
3259	void* __p = reinterpret_cast<void*>(&_S_empty_rep_storage);
3260	return *reinterpret_cast<_Rep*>(__p);
3261	}
3262
3263	bool
3264	_M_is_leaked() const _GLIBCXX_NOEXCEPT
3265	{
3266	#if defined(__GTHREADS)
3267	// _M_refcount is mutated concurrently by _M_refcopy/_M_dispose,
3268	// so we need to use an atomic load. However, _M_is_leaked
3269	// predicate does not change concurrently (i.e. the string is either
3270	// leaked or not), so a relaxed load is enough.
3271	return __atomic_load_n(&this->_M_refcount, __ATOMIC_RELAXED) < `0`;
3272	#else
3273	return this->_M_refcount < `0`;
3274	#endif
3275	}
3276
3277	bool
3278	_M_is_shared() const _GLIBCXX_NOEXCEPT
3279	{
3280	#if defined(__GTHREADS)
3281	// _M_refcount is mutated concurrently by _M_refcopy/_M_dispose,
3282	// so we need to use an atomic load. Another thread can drop last
3283	// but one reference concurrently with this check, so we need this
3284	// load to be acquire to synchronize with release fetch_and_add in
3285	// _M_dispose.
3286	return __atomic_load_n(&this->_M_refcount, __ATOMIC_ACQUIRE) > `0`;
3287	#else
3288	return this->_M_refcount > `0`;
3289	#endif
3290	}
3291
3292	void
3293	_M_set_leaked() _GLIBCXX_NOEXCEPT
3294	{ this->_M_refcount = -`1`; }
3295
3296	void
3297	_M_set_sharable() _GLIBCXX_NOEXCEPT
3298	{ this->_M_refcount = `0`; }
3299
3300	void
3301	_M_set_length_and_sharable(size_type __n) _GLIBCXX_NOEXCEPT
3302	{
3303	#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3304	if (__builtin_expect(this != &_S_empty_rep(), false))
3305	#endif
3306	{
3307	this->_M_set_sharable(); // One reference.
3308	this->_M_length = __n;
3309	traits_type::assign(this->_M_refdata()[__n], _S_terminal);
3310	// grrr. (per 21.3.4)
3311	// You cannot leave those LWG people alone for a second.
3312	}
3313	}
3314
3315	_CharT*
3316	_M_refdata() throw()
3317	{ return reinterpret_cast<_CharT>(this* + `1`); }
3318
3319	_CharT*
3320	_M_grab(const _Alloc& __alloc1, const _Alloc& __alloc2)
3321	{
3322	return (!_M_is_leaked() && __alloc1 == __alloc2)
3323	? _M_refcopy() : _M_clone(__alloc1);
3324	}
3325
3326	// Create & Destroy
3327	static _Rep*
3328	_S_create(size_type, size_type, const _Alloc&);
3329
3330	void
3331	_M_dispose(const _Alloc& __a) _GLIBCXX_NOEXCEPT
3332	{
3333	#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3334	if (__builtin_expect(this != &_S_empty_rep(), false))
3335	#endif
3336	{
3337	// Be race-detector-friendly. For more info see bits/c++config.
3338	_GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&this->_M_refcount);
3339	// Decrement of _M_refcount is acq_rel, because:
3340	// - all but last decrements need to release to synchronize with
3341	// the last decrement that will delete the object.
3342	// - the last decrement needs to acquire to synchronize with
3343	// all the previous decrements.
3344	// - last but one decrement needs to release to synchronize with
3345	// the acquire load in _M_is_shared that will conclude that
3346	// the object is not shared anymore.
3347	if (__gnu_cxx::__exchange_and_add_dispatch(&this->_M_refcount,
3348	-`1`) <= `0`)
3349	{
3350	_GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&this->_M_refcount);
3351	_M_destroy(__a);
3352	}
3353	}
3354	} // XXX MT
3355
3356	void
3357	_M_destroy(const _Alloc&) throw();
3358
3359	_CharT*
3360	_M_refcopy() throw()
3361	{
3362	#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3363	if (__builtin_expect(this != &_S_empty_rep(), false))
3364	#endif
3365	__gnu_cxx::__atomic_add_dispatch(&this->_M_refcount, `1`);
3366	return _M_refdata();
3367	} // XXX MT
3368
3369	_CharT*
3370	_M_clone(const _Alloc&, size_type __res = `0`);
3371	};
3372
3373	// Use empty-base optimization: http://www.cantrip.org/emptyopt.html
3374	struct _Alloc_hider : _Alloc
3375	{
3376	_Alloc_hider(_CharT* __dat, const _Alloc& __a) _GLIBCXX_NOEXCEPT
3377	: _Alloc(__a), _M_p(__dat) { }
3378
3379	_CharT* _M_p; // The actual data.
3380	};
3381
3382	public:
3383	// Data Members (public):
3384	// NB: This is an unsigned type, and thus represents the maximum
3385	// size that the allocator can hold.
3386	/// Value returned by various member functions when they fail.
3387	static const size_type npos = static_cast<size_type>(-`1`);
3388
3389	private:
3390	// Data Members (private):
3391	mutable _Alloc_hider _M_dataplus;
3392
3393	_CharT*
3394	_M_data() const _GLIBCXX_NOEXCEPT
3395	{ return _M_dataplus._M_p; }
3396
3397	_CharT*
3398	_M_data(_CharT* __p) _GLIBCXX_NOEXCEPT
3399	{ return (_M_dataplus._M_p = __p); }
3400
3401	_Rep*
3402	_M_rep() const _GLIBCXX_NOEXCEPT
3403	{ return &((reinterpret_cast<_Rep*> (_M_data()))[-`1`]); }
3404
3405	// For the internal use we have functions similar to `begin'/`end'
3406	// but they do not call _M_leak.
3407	iterator
3408	_M_ibegin() const _GLIBCXX_NOEXCEPT
3409	{ return iterator(_M_data()); }
3410
3411	iterator
3412	_M_iend() const _GLIBCXX_NOEXCEPT
3413	{ return iterator(_M_data() + this->size()); }
3414
3415	void
3416	_M_leak() // for use in begin() & non-const op[]
3417	{
3418	if (!_M_rep()->_M_is_leaked())
3419	_M_leak_hard();
3420	}
3421
3422	size_type
3423	_M_check(size_type __pos, const char* __s) const
3424	{
3425	if (__pos > this->size())
3426	__throw_out_of_range_fmt(__N("%s: __pos (which is %zu) > "
3427	"this->size() (which is %zu)"),
3428	__s, __pos, this->size());
3429	return __pos;
3430	}
3431
3432	void
3433	_M_check_length(size_type __n1, size_type __n2, const char* __s) const
3434	{
3435	if (this->max_size() - (this->size() - __n1) < __n2)
3436	__throw_length_error(__N(__s));
3437	}
3438
3439	// NB: _M_limit doesn't check for a bad __pos value.
3440	size_type
3441	_M_limit(size_type __pos, size_type __off) const _GLIBCXX_NOEXCEPT
3442	{
3443	const bool __testoff = __off < this->size() - __pos;
3444	return __testoff ? __off : this->size() - __pos;
3445	}
3446
3447	// True if _Rep and source do not overlap.
3448	bool
3449	_M_disjunct(const _CharT* __s) const _GLIBCXX_NOEXCEPT
3450	{
3451	return (less<const _CharT*>()(__s, _M_data())
3452	\|\| less<const _CharT>()(_M_data() + this*->size(), __s));
3453	}
3454
3455	// When __n = 1 way faster than the general multichar
3456	// traits_type::copy/move/assign.
3457	static void
3458	_M_copy(_CharT* __d, const _CharT* __s, size_type __n) _GLIBCXX_NOEXCEPT
3459	{
3460	if (__n == `1`)
3461	traits_type::assign(__d, __s);
3462	else
3463	traits_type::copy(__d, __s, __n);
3464	}
3465
3466	static void
3467	_M_move(_CharT* __d, const _CharT* __s, size_type __n) _GLIBCXX_NOEXCEPT
3468	{
3469	if (__n == `1`)
3470	traits_type::assign(__d, __s);
3471	else
3472	traits_type::move(__d, __s, __n);
3473	}
3474
3475	static void
3476	_M_assign(_CharT* __d, size_type __n, _CharT __c) _GLIBCXX_NOEXCEPT
3477	{
3478	if (__n == `1`)
3479	traits_type::assign(*__d, __c);
3480	else
3481	traits_type::assign(__d, __n, __c);
3482	}
3483
3484	// _S_copy_chars is a separate template to permit specialization
3485	// to optimize for the common case of pointers as iterators.
3486	template<class _Iterator>
3487	static void
3488	_S_copy_chars(_CharT* __p, _Iterator __k1, _Iterator __k2)
3489	{
3490	for (; __k1 != __k2; ++__k1, (void)++__p)
3491	traits_type::assign(__p, __k1); // These types are off.
3492	}
3493
3494	static void
3495	_S_copy_chars(_CharT* __p, iterator __k1, iterator __k2) _GLIBCXX_NOEXCEPT
3496	{ _S_copy_chars(__p, __k1.base(), __k2.base()); }
3497
3498	static void
3499	_S_copy_chars(_CharT* __p, const_iterator __k1, const_iterator __k2)
3500	_GLIBCXX_NOEXCEPT
3501	{ _S_copy_chars(__p, __k1.base(), __k2.base()); }
3502
3503	static void
3504	_S_copy_chars(_CharT* __p, _CharT* __k1, _CharT* __k2) _GLIBCXX_NOEXCEPT
3505	{ _M_copy(__p, __k1, __k2 - __k1); }
3506
3507	static void
3508	_S_copy_chars(_CharT* __p, const _CharT* __k1, const _CharT* __k2)
3509	_GLIBCXX_NOEXCEPT
3510	{ _M_copy(__p, __k1, __k2 - __k1); }
3511
3512	static int
3513	_S_compare(size_type __n1, size_type __n2) _GLIBCXX_NOEXCEPT
3514	{
3515	const difference_type __d = difference_type(__n1 - __n2);
3516
3517	if (__d > __gnu_cxx::__numeric_traits<int>::__max)
3518	return __gnu_cxx::__numeric_traits<int>::__max;
3519	else if (__d < __gnu_cxx::__numeric_traits<int>::__min)
3520	return __gnu_cxx::__numeric_traits<int>::__min;
3521	else
3522	return int(__d);
3523	}
3524
3525	void
3526	_M_mutate(size_type __pos, size_type __len1, size_type __len2);
3527
3528	void
3529	_M_leak_hard();
3530
3531	static _Rep&
3532	_S_empty_rep() _GLIBCXX_NOEXCEPT
3533	{ return _Rep::_S_empty_rep(); }
3534
3535	#if __cplusplus >= 201703L
3536	// A helper type for avoiding boiler-plate.
3537	typedef basic_string_view<_CharT, _Traits> __sv_type;
3538
3539	template<typename _Tp, typename _Res>
3540	using _If_sv = enable_if_t<
3541	__and_<is_convertible<const _Tp&, __sv_type>,
3542	__not_<is_convertible<const _Tp, const* basic_string*>>,
3543	__not_<is_convertible<const _Tp&, const _CharT*>>>::value,
3544	_Res>;
3545
3546	// Allows an implicit conversion to __sv_type.
3547	static __sv_type
3548	_S_to_string_view(__sv_type __svt) noexcept
3549	{ return __svt; }
3550
3551	// Wraps a string_view by explicit conversion and thus
3552	// allows to add an internal constructor that does not
3553	// participate in overload resolution when a string_view
3554	// is provided.
3555	struct __sv_wrapper
3556	{
3557	explicit __sv_wrapper(__sv_type __sv) noexcept : _M_sv(__sv) { }
3558	__sv_type _M_sv;
3559	};
3560
3561	/**
3562	* @brief Only internally used: Construct string from a string view
3563	* wrapper.
3564	* @param __svw string view wrapper.
3565	* @param __a Allocator to use.
3566	*/
3567	explicit
3568	basic_string(__sv_wrapper __svw, const _Alloc& __a)
3569	: basic_string(__svw._M_sv.data(), __svw._M_sv.size(), __a) { }
3570	#endif
3571
3572	public:
3573	// Construct/copy/destroy:
3574	// NB: We overload ctors in some cases instead of using default
3575	// arguments, per 17.4.4.4 para. 2 item 2.
3576
3577	/**
3578	* @brief Default constructor creates an empty string.
3579	*/
3580	basic_string()
3581	#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3582	_GLIBCXX_NOEXCEPT
3583	: _M_dataplus(_S_empty_rep()._M_refdata(), _Alloc())
3584	#else
3585	: _M_dataplus(_S_construct(size_type(), _CharT(), _Alloc()), _Alloc())
3586	#endif
3587	{ }
3588
3589	/**
3590	* @brief Construct an empty string using allocator @a a.
3591	*/
3592	explicit
3593	basic_string(const _Alloc& __a)
3594	: _M_dataplus(_S_construct(size_type(), _CharT(), __a), __a)
3595	{ }
3596
3597	// NB: per LWG issue 42, semantics different from IS:
3598	/**
3599	* @brief Construct string with copy of value of @a str.
3600	* @param __str Source string.
3601	*/
3602	basic_string(const basic_string& __str)
3603	: _M_dataplus(__str._M_rep()->_M_grab(_Alloc(__str.get_allocator()),
3604	__str.get_allocator()),
3605	__str.get_allocator())
3606	{ }
3607
3608	// _GLIBCXX_RESOLVE_LIB_DEFECTS
3609	// 2583. no way to supply an allocator for basic_string(str, pos)
3610	/**
3611	* @brief Construct string as copy of a substring.
3612	* @param __str Source string.
3613	* @param __pos Index of first character to copy from.
3614	* @param __a Allocator to use.
3615	*/
3616	basic_string(const basic_string& __str, size_type __pos,
3617	const _Alloc& __a = _Alloc());
3618
3619	/**
3620	* @brief Construct string as copy of a substring.
3621	* @param __str Source string.
3622	* @param __pos Index of first character to copy from.
3623	* @param __n Number of characters to copy.
3624	*/
3625	basic_string(const basic_string& __str, size_type __pos,
3626	size_type __n);
3627	/**
3628	* @brief Construct string as copy of a substring.
3629	* @param __str Source string.
3630	* @param __pos Index of first character to copy from.
3631	* @param __n Number of characters to copy.
3632	* @param __a Allocator to use.
3633	*/
3634	basic_string(const basic_string& __str, size_type __pos,
3635	size_type __n, const _Alloc& __a);
3636
3637	/**
3638	* @brief Construct string initialized by a character %array.
3639	* @param __s Source character %array.
3640	* @param __n Number of characters to copy.
3641	* @param __a Allocator to use (default is default allocator).
3642	*
3643	* NB: @a __s must have at least @a __n characters, '\\0'
3644	* has no special meaning.
3645	*/
3646	basic_string(const _CharT* __s, size_type __n,
3647	const _Alloc& __a = _Alloc())
3648	: _M_dataplus(_S_construct(__s, __s + __n, __a), __a)
3649	{ }
3650
3651	/**
3652	* @brief Construct string as copy of a C string.
3653	* @param __s Source C string.
3654	* @param __a Allocator to use (default is default allocator).
3655	*/
3656	#if __cpp_deduction_guides && ! defined _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
3657	// _GLIBCXX_RESOLVE_LIB_DEFECTS
3658	// 3076. basic_string CTAD ambiguity
3659	template<typename = _RequireAllocator<_Alloc>>
3660	#endif
3661	basic_string(const _CharT* __s, const _Alloc& __a = _Alloc())
3662	: _M_dataplus(_S_construct(__s, __s ? __s + traits_type::length(__s) :
3663	__s + npos, __a), __a)
3664	{ }
3665
3666	/**
3667	* @brief Construct string as multiple characters.
3668	* @param __n Number of characters.
3669	* @param __c Character to use.
3670	* @param __a Allocator to use (default is default allocator).
3671	*/
3672	basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc())
3673	: _M_dataplus(_S_construct(__n, __c, __a), __a)
3674	{ }
3675
3676	#if __cplusplus >= 201103L
3677	/**
3678	* @brief Move construct string.
3679	* @param __str Source string.
3680	*
3681	* The newly-created string contains the exact contents of @a __str.
3682	* @a __str is a valid, but unspecified string.
3683	*/
3684	basic_string(basic_string&& __str)
3685	#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3686	noexcept // FIXME C++11: should always be noexcept.
3687	#endif
3688	: _M_dataplus(std::move(__str._M_dataplus))
3689	{
3690	#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3691	__str._M_data(_S_empty_rep()._M_refdata());
3692	#else
3693	__str._M_data(_S_construct(size_type(), _CharT(), get_allocator()));
3694	#endif
3695	}
3696
3697	/**
3698	* @brief Construct string from an initializer %list.
3699	* @param __l std::initializer_list of characters.
3700	* @param __a Allocator to use (default is default allocator).
3701	*/
3702	basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc())
3703	: _M_dataplus(_S_construct(__l.begin(), __l.end(), __a), __a)
3704	{ }
3705
3706	basic_string(const basic_string& __str, const _Alloc& __a)
3707	: _M_dataplus(__str._M_rep()->_M_grab(__a, __str.get_allocator()), __a)
3708	{ }
3709
3710	basic_string(basic_string&& __str, const _Alloc& __a)
3711	: _M_dataplus(__str._M_data(), __a)
3712	{
3713	if (__a == __str.get_allocator())
3714	{
3715	#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3716	__str._M_data(_S_empty_rep()._M_refdata());
3717	#else
3718	__str._M_data(_S_construct(size_type(), _CharT(), __a));
3719	#endif
3720	}
3721	else
3722	_M_dataplus._M_p = _S_construct(__str.begin(), __str.end(), __a);
3723	}
3724	#endif // C++11
3725
3726	/**
3727	* @brief Construct string as copy of a range.
3728	* @param __beg Start of range.
3729	* @param __end End of range.
3730	* @param __a Allocator to use (default is default allocator).
3731	*/
3732	template<class _InputIterator>
3733	basic_string(_InputIterator __beg, _InputIterator __end,
3734	const _Alloc& __a = _Alloc())
3735	: _M_dataplus(_S_construct(__beg, __end, __a), __a)
3736	{ }
3737
3738	#if __cplusplus >= 201703L
3739	/**
3740	* @brief Construct string from a substring of a string_view.
3741	* @param __t Source object convertible to string view.
3742	* @param __pos The index of the first character to copy from __t.
3743	* @param __n The number of characters to copy from __t.
3744	* @param __a Allocator to use.
3745	*/
3746	template<typename _Tp, typename = _If_sv<_Tp, void>>
3747	basic_string(const _Tp& __t, size_type __pos, size_type __n,
3748	const _Alloc& __a = _Alloc())
3749	: basic_string(_S_to_string_view(__t).substr(__pos, __n), __a) { }
3750
3751	/**
3752	* @brief Construct string from a string_view.
3753	* @param __t Source object convertible to string view.
3754	* @param __a Allocator to use (default is default allocator).
3755	*/
3756	template<typename _Tp, typename = _If_sv<_Tp, void>>
3757	explicit
3758	basic_string(const _Tp& __t, const _Alloc& __a = _Alloc())
3759	: basic_string(__sv_wrapper(_S_to_string_view(__t)), __a) { }
3760	#endif // C++17
3761
3762	/**
3763	* @brief Destroy the string instance.
3764	*/
3765	~basic_string() _GLIBCXX_NOEXCEPT
3766	{ _M_rep()->_M_dispose(this->get_allocator()); }
3767
3768	/**
3769	* @brief Assign the value of @a str to this string.
3770	* @param __str Source string.
3771	*/
3772	basic_string&
3773	operator=(const basic_string& __str)
3774	{ return this->assign(__str); }
3775
3776	/**
3777	* @brief Copy contents of @a s into this string.
3778	* @param __s Source null-terminated string.
3779	*/
3780	basic_string&
3781	operator=(const _CharT* __s)
3782	{ return this->assign(__s); }
3783
3784	/**
3785	* @brief Set value to string of length 1.
3786	* @param __c Source character.
3787	*
3788	* Assigning to a character makes this string length 1 and
3789	* (*this)[0] == @a c.
3790	*/
3791	basic_string&
3792	operator=(_CharT __c)
3793	{
3794	this->assign(`1`, __c);
3795	return *this;
3796	}
3797
3798	#if __cplusplus >= 201103L
3799	/**
3800	* @brief Move assign the value of @a str to this string.
3801	* @param __str Source string.
3802	*
3803	* The contents of @a str are moved into this string (without copying).
3804	* @a str is a valid, but unspecified string.
3805	*/
3806	basic_string&
3807	operator=(basic_string&& __str)
3808	_GLIBCXX_NOEXCEPT_IF(allocator_traits<_Alloc>::is_always_equal::value)
3809	{
3810	// NB: DR 1204.
3811	this->swap(__str);
3812	return *this;
3813	}
3814
3815	/**
3816	* @brief Set value to string constructed from initializer %list.
3817	* @param __l std::initializer_list.
3818	*/
3819	basic_string&
3820	operator=(initializer_list<_CharT> __l)
3821	{
3822	this->assign(__l.begin(), __l.size());
3823	return *this;
3824	}
3825	#endif // C++11
3826
3827	#if __cplusplus >= 201703L
3828	/**
3829	* @brief Set value to string constructed from a string_view.
3830	* @param __svt An object convertible to string_view.
3831	*/
3832	template<typename _Tp>
3833	_If_sv<_Tp, basic_string&>
3834	operator=(const _Tp& __svt)
3835	{ return this->assign(__svt); }
3836
3837	/**
3838	* @brief Convert to a string_view.
3839	* @return A string_view.
3840	*/
3841	operator __sv_type() const noexcept
3842	{ return __sv_type(data(), size()); }
3843	#endif // C++17
3844
3845	// Iterators:
3846	/**
3847	* Returns a read/write iterator that points to the first character in
3848	* the %string. Unshares the string.
3849	*/
3850	iterator
3851	begin() // FIXME C++11: should be noexcept.
3852	{
3853	_M_leak();
3854	return iterator(_M_data());
3855	}
3856
3857	/**
3858	* Returns a read-only (constant) iterator that points to the first
3859	* character in the %string.
3860	*/
3861	const_iterator
3862	begin() const _GLIBCXX_NOEXCEPT
3863	{ return const_iterator(_M_data()); }
3864
3865	/**
3866	* Returns a read/write iterator that points one past the last
3867	* character in the %string. Unshares the string.
3868	*/
3869	iterator
3870	end() // FIXME C++11: should be noexcept.
3871	{
3872	_M_leak();
3873	return iterator(_M_data() + this->size());
3874	}
3875
3876	/**
3877	* Returns a read-only (constant) iterator that points one past the
3878	* last character in the %string.
3879	*/
3880	const_iterator
3881	end() const _GLIBCXX_NOEXCEPT
3882	{ return const_iterator(_M_data() + this->size()); }
3883
3884	/**
3885	* Returns a read/write reverse iterator that points to the last
3886	* character in the %string. Iteration is done in reverse element
3887	* order. Unshares the string.
3888	*/
3889	reverse_iterator
3890	rbegin() // FIXME C++11: should be noexcept.
3891	{ return reverse_iterator(this->end()); }
3892
3893	/**
3894	* Returns a read-only (constant) reverse iterator that points
3895	* to the last character in the %string. Iteration is done in
3896	* reverse element order.
3897	*/
3898	const_reverse_iterator
3899	rbegin() const _GLIBCXX_NOEXCEPT
3900	{ return const_reverse_iterator(this->end()); }
3901
3902	/**
3903	* Returns a read/write reverse iterator that points to one before the
3904	* first character in the %string. Iteration is done in reverse
3905	* element order. Unshares the string.
3906	*/
3907	reverse_iterator
3908	rend() // FIXME C++11: should be noexcept.
3909	{ return reverse_iterator(this->begin()); }
3910
3911	/**
3912	* Returns a read-only (constant) reverse iterator that points
3913	* to one before the first character in the %string. Iteration
3914	* is done in reverse element order.
3915	*/
3916	const_reverse_iterator
3917	rend() const _GLIBCXX_NOEXCEPT
3918	{ return const_reverse_iterator(this->begin()); }
3919
3920	#if __cplusplus >= 201103L
3921	/**
3922	* Returns a read-only (constant) iterator that points to the first
3923	* character in the %string.
3924	*/
3925	const_iterator
3926	cbegin() const noexcept
3927	{ return const_iterator(this->_M_data()); }
3928
3929	/**
3930	* Returns a read-only (constant) iterator that points one past the
3931	* last character in the %string.
3932	*/
3933	const_iterator
3934	cend() const noexcept
3935	{ return const_iterator(this->_M_data() + this->size()); }
3936
3937	/**
3938	* Returns a read-only (constant) reverse iterator that points
3939	* to the last character in the %string. Iteration is done in
3940	* reverse element order.
3941	*/
3942	const_reverse_iterator
3943	crbegin() const noexcept
3944	{ return const_reverse_iterator(this->end()); }
3945
3946	/**
3947	* Returns a read-only (constant) reverse iterator that points
3948	* to one before the first character in the %string. Iteration
3949	* is done in reverse element order.
3950	*/
3951	const_reverse_iterator
3952	crend() const noexcept
3953	{ return const_reverse_iterator(this->begin()); }
3954	#endif
3955
3956	public:
3957	// Capacity:
3958	/// Returns the number of characters in the string, not including any
3959	/// null-termination.
3960	size_type
3961	size() const _GLIBCXX_NOEXCEPT
3962	{ return _M_rep()->_M_length; }
3963
3964	/// Returns the number of characters in the string, not including any
3965	/// null-termination.
3966	size_type
3967	length() const _GLIBCXX_NOEXCEPT
3968	{ return _M_rep()->_M_length; }
3969
3970	/// Returns the size() of the largest possible %string.
3971	size_type
3972	max_size() const _GLIBCXX_NOEXCEPT
3973	{ return _Rep::_S_max_size; }
3974
3975	/**
3976	* @brief Resizes the %string to the specified number of characters.
3977	* @param __n Number of characters the %string should contain.
3978	* @param __c Character to fill any new elements.
3979	*
3980	* This function will %resize the %string to the specified
3981	* number of characters. If the number is smaller than the
3982	* %string's current size the %string is truncated, otherwise
3983	* the %string is extended and new elements are %set to @a __c.
3984	*/
3985	void
3986	resize(size_type __n, _CharT __c);
3987
3988	/**
3989	* @brief Resizes the %string to the specified number of characters.
3990	* @param __n Number of characters the %string should contain.
3991	*
3992	* This function will resize the %string to the specified length. If
3993	* the new size is smaller than the %string's current size the %string
3994	* is truncated, otherwise the %string is extended and new characters
3995	* are default-constructed. For basic types such as char, this means
3996	* setting them to 0.
3997	*/
3998	void
3999	resize(size_type __n)
4000	{ this->resize(__n, _CharT()); }
4001
4002	#if __cplusplus >= 201103L
4003	#pragma GCC diagnostic push
4004	#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
4005	/// A non-binding request to reduce capacity() to size().
4006	void
4007	shrink_to_fit() noexcept
4008	{ reserve(); }
4009	#pragma GCC diagnostic pop
4010	#endif
4011
4012	/**
4013	* Returns the total number of characters that the %string can hold
4014	* before needing to allocate more memory.
4015	*/
4016	size_type
4017	capacity() const _GLIBCXX_NOEXCEPT
4018	{ return _M_rep()->_M_capacity; }
4019
4020	/**
4021	* @brief Attempt to preallocate enough memory for specified number of
4022	* characters.
4023	* @param __res_arg Number of characters required.
4024	* @throw std::length_error If @a __res_arg exceeds @c max_size().
4025	*
4026	* This function attempts to reserve enough memory for the
4027	* %string to hold the specified number of characters. If the
4028	* number requested is more than max_size(), length_error is
4029	* thrown.
4030	*
4031	* The advantage of this function is that if optimal code is a
4032	* necessity and the user can determine the string length that will be
4033	* required, the user can reserve the memory in %advance, and thus
4034	* prevent a possible reallocation of memory and copying of %string
4035	* data.
4036	*/
4037	void
4038	reserve(size_type __res_arg);
4039
4040	/// Equivalent to shrink_to_fit().
4041	#if __cplusplus > 201703L
4042	[[deprecated("use shrink_to_fit() instead")]]
4043	#endif
4044	void
4045	reserve();
4046
4047	/**
4048	* Erases the string, making it empty.
4049	*/
4050	#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
4051	void
4052	clear() _GLIBCXX_NOEXCEPT
4053	{
4054	if (_M_rep()->_M_is_shared())
4055	{
4056	_M_rep()->_M_dispose(this->get_allocator());
4057	_M_data(_S_empty_rep()._M_refdata());
4058	}
4059	else
4060	_M_rep()->_M_set_length_and_sharable(`0`);
4061	}
4062	#else
4063	// PR 56166: this should not throw.
4064	void
4065	clear()
4066	{ _M_mutate(`0`, this->size(), `0`); }
4067	#endif
4068
4069	/**
4070	* Returns true if the %string is empty. Equivalent to
4071	* <code>*this == ""</code>.
4072	*/
4073	_GLIBCXX_NODISCARD bool
4074	empty() const _GLIBCXX_NOEXCEPT
4075	{ return this->size() == `0`; }
4076
4077	// Element access:
4078	/**
4079	* @brief Subscript access to the data contained in the %string.
4080	* @param __pos The index of the character to access.
4081	* @return Read-only (constant) reference to the character.
4082	*
4083	* This operator allows for easy, array-style, data access.
4084	* Note that data access with this operator is unchecked and
4085	* out_of_range lookups are not defined. (For checked lookups
4086	* see at().)
4087	*/
4088	const_reference
4089	operator[] (size_type __pos) const _GLIBCXX_NOEXCEPT
4090	{
4091	__glibcxx_assert(__pos <= size());
4092	return _M_data()[__pos];
4093	}
4094
4095	/**
4096	* @brief Subscript access to the data contained in the %string.
4097	* @param __pos The index of the character to access.
4098	* @return Read/write reference to the character.
4099	*
4100	* This operator allows for easy, array-style, data access.
4101	* Note that data access with this operator is unchecked and
4102	* out_of_range lookups are not defined. (For checked lookups
4103	* see at().) Unshares the string.
4104	*/
4105	reference
4106	operator[](size_type __pos)
4107	{
4108	// Allow pos == size() both in C++98 mode, as v3 extension,
4109	// and in C++11 mode.
4110	__glibcxx_assert(__pos <= size());
4111	// In pedantic mode be strict in C++98 mode.
4112	_GLIBCXX_DEBUG_PEDASSERT(__cplusplus >= `201103L` \|\| __pos < size());
4113	_M_leak();
4114	return _M_data()[__pos];
4115	}
4116
4117	/**
4118	* @brief Provides access to the data contained in the %string.
4119	* @param __n The index of the character to access.
4120	* @return Read-only (const) reference to the character.
4121	* @throw std::out_of_range If @a n is an invalid index.
4122	*
4123	* This function provides for safer data access. The parameter is
4124	* first checked that it is in the range of the string. The function
4125	* throws out_of_range if the check fails.
4126	*/
4127	const_reference
4128	at(size_type __n) const
4129	{
4130	if (__n >= this->size())
4131	__throw_out_of_range_fmt(__N("basic_string::at: __n "
4132	"(which is %zu) >= this->size() "
4133	"(which is %zu)"),
4134	__n, this->size());
4135	return _M_data()[__n];
4136	}
4137
4138	/**
4139	* @brief Provides access to the data contained in the %string.
4140	* @param __n The index of the character to access.
4141	* @return Read/write reference to the character.
4142	* @throw std::out_of_range If @a n is an invalid index.
4143	*
4144	* This function provides for safer data access. The parameter is
4145	* first checked that it is in the range of the string. The function
4146	* throws out_of_range if the check fails. Success results in
4147	* unsharing the string.
4148	*/
4149	reference
4150	at(size_type __n)
4151	{
4152	if (__n >= size())
4153	__throw_out_of_range_fmt(__N("basic_string::at: __n "
4154	"(which is %zu) >= this->size() "
4155	"(which is %zu)"),
4156	__n, this->size());
4157	_M_leak();
4158	return _M_data()[__n];
4159	}
4160
4161	#if __cplusplus >= 201103L
4162	/**
4163	* Returns a read/write reference to the data at the first
4164	* element of the %string.
4165	*/
4166	reference
4167	front()
4168	{
4169	__glibcxx_assert(!empty());
4170	return operator[](`0`);
4171	}
4172
4173	/**
4174	* Returns a read-only (constant) reference to the data at the first
4175	* element of the %string.
4176	*/
4177	const_reference
4178	front() const noexcept
4179	{
4180	__glibcxx_assert(!empty());
4181	return operator[](`0`);
4182	}
4183
4184	/**
4185	* Returns a read/write reference to the data at the last
4186	* element of the %string.
4187	*/
4188	reference
4189	back()
4190	{
4191	__glibcxx_assert(!empty());
4192	return operator[](this->size() - `1`);
4193	}
4194
4195	/**
4196	* Returns a read-only (constant) reference to the data at the
4197	* last element of the %string.
4198	*/
4199	const_reference
4200	back() const noexcept
4201	{
4202	__glibcxx_assert(!empty());
4203	return operator[](this->size() - `1`);
4204	}
4205	#endif
4206
4207	// Modifiers:
4208	/**
4209	* @brief Append a string to this string.
4210	* @param __str The string to append.
4211	* @return Reference to this string.
4212	*/
4213	basic_string&
4214	operator+=(const basic_string& __str)
4215	{ return this->append(__str); }
4216
4217	/**
4218	* @brief Append a C string.
4219	* @param __s The C string to append.
4220	* @return Reference to this string.
4221	*/
4222	basic_string&
4223	operator+=(const _CharT* __s)
4224	{ return this->append(__s); }
4225
4226	/**
4227	* @brief Append a character.
4228	* @param __c The character to append.
4229	* @return Reference to this string.
4230	*/
4231	basic_string&
4232	operator+=(_CharT __c)
4233	{
4234	this->push_back(__c);
4235	return *this;
4236	}
4237
4238	#if __cplusplus >= 201103L
4239	/**
4240	* @brief Append an initializer_list of characters.
4241	* @param __l The initializer_list of characters to be appended.
4242	* @return Reference to this string.
4243	*/
4244	basic_string&
4245	operator+=(initializer_list<_CharT> __l)
4246	{ return this->append(__l.begin(), __l.size()); }
4247	#endif // C++11
4248
4249	#if __cplusplus >= 201703L
4250	/**
4251	* @brief Append a string_view.
4252	* @param __svt The object convertible to string_view to be appended.
4253	* @return Reference to this string.
4254	*/
4255	template<typename _Tp>
4256	_If_sv<_Tp, basic_string&>
4257	operator+=(const _Tp& __svt)
4258	{ return this->append(__svt); }
4259	#endif // C++17
4260
4261	/**
4262	* @brief Append a string to this string.
4263	* @param __str The string to append.
4264	* @return Reference to this string.
4265	*/
4266	basic_string&
4267	append(const basic_string& __str);
4268
4269	/**
4270	* @brief Append a substring.
4271	* @param __str The string to append.
4272	* @param __pos Index of the first character of str to append.
4273	* @param __n The number of characters to append.
4274	* @return Reference to this string.
4275	* @throw std::out_of_range if @a __pos is not a valid index.
4276	*
4277	* This function appends @a __n characters from @a __str
4278	* starting at @a __pos to this string. If @a __n is is larger
4279	* than the number of available characters in @a __str, the
4280	* remainder of @a __str is appended.
4281	*/
4282	basic_string&
4283	append(const basic_string& __str, size_type __pos, size_type __n = npos);
4284
4285	/**
4286	* @brief Append a C substring.
4287	* @param __s The C string to append.
4288	* @param __n The number of characters to append.
4289	* @return Reference to this string.
4290	*/
4291	basic_string&
4292	append(const _CharT* __s, size_type __n);
4293
4294	/**
4295	* @brief Append a C string.
4296	* @param __s The C string to append.
4297	* @return Reference to this string.
4298	*/
4299	basic_string&
4300	append(const _CharT* __s)
4301	{
4302	__glibcxx_requires_string(__s);
4303	return this->append(__s, traits_type::length(__s));
4304	}
4305
4306	/**
4307	* @brief Append multiple characters.
4308	* @param __n The number of characters to append.
4309	* @param __c The character to use.
4310	* @return Reference to this string.
4311	*
4312	* Appends __n copies of __c to this string.
4313	*/
4314	basic_string&
4315	append(size_type __n, _CharT __c);
4316
4317	#if __cplusplus >= 201103L
4318	/**
4319	* @brief Append an initializer_list of characters.
4320	* @param __l The initializer_list of characters to append.
4321	* @return Reference to this string.
4322	*/
4323	basic_string&
4324	append(initializer_list<_CharT> __l)
4325	{ return this->append(__l.begin(), __l.size()); }
4326	#endif // C++11
4327
4328	/**
4329	* @brief Append a range of characters.
4330	* @param __first Iterator referencing the first character to append.
4331	* @param __last Iterator marking the end of the range.
4332	* @return Reference to this string.
4333	*
4334	* Appends characters in the range [__first,__last) to this string.
4335	*/
4336	template<class _InputIterator>
4337	basic_string&
4338	append(_InputIterator __first, _InputIterator __last)
4339	{ return this->replace(_M_iend(), _M_iend(), __first, __last); }
4340
4341	#if __cplusplus >= 201703L
4342	/**
4343	* @brief Append a string_view.
4344	* @param __svt The object convertible to string_view to be appended.
4345	* @return Reference to this string.
4346	*/
4347	template<typename _Tp>
4348	_If_sv<_Tp, basic_string&>
4349	append(const _Tp& __svt)
4350	{
4351	__sv_type __sv = __svt;
4352	return this->append(__sv.data(), __sv.size());
4353	}
4354
4355	/**
4356	* @brief Append a range of characters from a string_view.
4357	* @param __svt The object convertible to string_view to be appended
4358	* from.
4359	* @param __pos The position in the string_view to append from.
4360	* @param __n The number of characters to append from the string_view.
4361	* @return Reference to this string.
4362	*/
4363	template<typename _Tp>
4364	_If_sv<_Tp, basic_string&>
4365	append(const _Tp& __svt, size_type __pos, size_type __n = npos)
4366	{
4367	__sv_type __sv = __svt;
4368	return append(__sv.data()
4369	+ std::__sv_check(__sv.size(), __pos, "basic_string::append"),
4370	std::__sv_limit(__sv.size(), __pos, __n));
4371	}
4372	#endif // C++17
4373
4374	/**
4375	* @brief Append a single character.
4376	* @param __c Character to append.
4377	*/
4378	void
4379	push_back(_CharT __c)
4380	{
4381	const size_type __len = `1` + this->size();
4382	if (__len > this->capacity() \|\| _M_rep()->_M_is_shared())
4383	this->reserve(__len);
4384	traits_type::assign(_M_data()[this->size()], __c);
4385	_M_rep()->_M_set_length_and_sharable(__len);
4386	}
4387
4388	/**
4389	* @brief Set value to contents of another string.
4390	* @param __str Source string to use.
4391	* @return Reference to this string.
4392	*/
4393	basic_string&
4394	assign(const basic_string& __str);
4395
4396	#if __cplusplus >= 201103L
4397	/**
4398	* @brief Set value to contents of another string.
4399	* @param __str Source string to use.
4400	* @return Reference to this string.
4401	*
4402	* This function sets this string to the exact contents of @a __str.
4403	* @a __str is a valid, but unspecified string.
4404	*/
4405	basic_string&
4406	assign(basic_string&& __str)
4407	noexcept(allocator_traits<_Alloc>::is_always_equal::value)
4408	{
4409	this->swap(__str);
4410	return *this;
4411	}
4412	#endif // C++11
4413
4414	/**
4415	* @brief Set value to a substring of a string.
4416	* @param __str The string to use.
4417	* @param __pos Index of the first character of str.
4418	* @param __n Number of characters to use.
4419	* @return Reference to this string.
4420	* @throw std::out_of_range if @a pos is not a valid index.
4421	*
4422	* This function sets this string to the substring of @a __str
4423	* consisting of @a __n characters at @a __pos. If @a __n is
4424	* is larger than the number of available characters in @a
4425	* __str, the remainder of @a __str is used.
4426	*/
4427	basic_string&
4428	assign(const basic_string& __str, size_type __pos, size_type __n = npos)
4429	{ return this->assign(__str._M_data()
4430	+ __str._M_check(__pos, "basic_string::assign"),
4431	__str._M_limit(__pos, __n)); }
4432
4433	/**
4434	* @brief Set value to a C substring.
4435	* @param __s The C string to use.
4436	* @param __n Number of characters to use.
4437	* @return Reference to this string.
4438	*
4439	* This function sets the value of this string to the first @a __n
4440	* characters of @a __s. If @a __n is is larger than the number of
4441	* available characters in @a __s, the remainder of @a __s is used.
4442	*/
4443	basic_string&
4444	assign(const _CharT* __s, size_type __n);
4445
4446	/**
4447	* @brief Set value to contents of a C string.
4448	* @param __s The C string to use.
4449	* @return Reference to this string.
4450	*
4451	* This function sets the value of this string to the value of @a __s.
4452	* The data is copied, so there is no dependence on @a __s once the
4453	* function returns.
4454	*/
4455	basic_string&
4456	assign(const _CharT* __s)
4457	{
4458	__glibcxx_requires_string(__s);
4459	return this->assign(__s, traits_type::length(__s));
4460	}
4461
4462	/**
4463	* @brief Set value to multiple characters.
4464	* @param __n Length of the resulting string.
4465	* @param __c The character to use.
4466	* @return Reference to this string.
4467	*
4468	* This function sets the value of this string to @a __n copies of
4469	* character @a __c.
4470	*/
4471	basic_string&
4472	assign(size_type __n, _CharT __c)
4473	{ return _M_replace_aux(size_type(`0`), this->size(), __n, __c); }
4474
4475	/**
4476	* @brief Set value to a range of characters.
4477	* @param __first Iterator referencing the first character to append.
4478	* @param __last Iterator marking the end of the range.
4479	* @return Reference to this string.
4480	*
4481	* Sets value of string to characters in the range [__first,__last).
4482	*/
4483	template<class _InputIterator>
4484	basic_string&
4485	assign(_InputIterator __first, _InputIterator __last)
4486	{ return this->replace(_M_ibegin(), _M_iend(), __first, __last); }
4487
4488	#if __cplusplus >= 201103L
4489	/**
4490	* @brief Set value to an initializer_list of characters.
4491	* @param __l The initializer_list of characters to assign.
4492	* @return Reference to this string.
4493	*/
4494	basic_string&
4495	assign(initializer_list<_CharT> __l)
4496	{ return this->assign(__l.begin(), __l.size()); }
4497	#endif // C++11
4498
4499	#if __cplusplus >= 201703L
4500	/**
4501	* @brief Set value from a string_view.
4502	* @param __svt The source object convertible to string_view.
4503	* @return Reference to this string.
4504	*/
4505	template<typename _Tp>
4506	_If_sv<_Tp, basic_string&>
4507	assign(const _Tp& __svt)
4508	{
4509	__sv_type __sv = __svt;
4510	return this->assign(__sv.data(), __sv.size());
4511	}
4512
4513	/**
4514	* @brief Set value from a range of characters in a string_view.
4515	* @param __svt The source object convertible to string_view.
4516	* @param __pos The position in the string_view to assign from.
4517	* @param __n The number of characters to assign.
4518	* @return Reference to this string.
4519	*/
4520	template<typename _Tp>
4521	_If_sv<_Tp, basic_string&>
4522	assign(const _Tp& __svt, size_type __pos, size_type __n = npos)
4523	{
4524	__sv_type __sv = __svt;
4525	return assign(__sv.data()
4526	+ std::__sv_check(__sv.size(), __pos, "basic_string::assign"),
4527	std::__sv_limit(__sv.size(), __pos, __n));
4528	}
4529	#endif // C++17
4530
4531	/**
4532	* @brief Insert multiple characters.
4533	* @param __p Iterator referencing location in string to insert at.
4534	* @param __n Number of characters to insert
4535	* @param __c The character to insert.
4536	* @throw std::length_error If new length exceeds @c max_size().
4537	*
4538	* Inserts @a __n copies of character @a __c starting at the
4539	* position referenced by iterator @a __p. If adding
4540	* characters causes the length to exceed max_size(),
4541	* length_error is thrown. The value of the string doesn't
4542	* change if an error is thrown.
4543	*/
4544	void
4545	insert(iterator __p, size_type __n, _CharT __c)
4546	{ this->replace(__p, __p, __n, __c); }
4547
4548	/**
4549	* @brief Insert a range of characters.
4550	* @param __p Iterator referencing location in string to insert at.
4551	* @param __beg Start of range.
4552	* @param __end End of range.
4553	* @throw std::length_error If new length exceeds @c max_size().
4554	*
4555	* Inserts characters in range [__beg,__end). If adding
4556	* characters causes the length to exceed max_size(),
4557	* length_error is thrown. The value of the string doesn't
4558	* change if an error is thrown.
4559	*/
4560	template<class _InputIterator>
4561	void
4562	insert(iterator __p, _InputIterator __beg, _InputIterator __end)
4563	{ this->replace(__p, __p, __beg, __end); }
4564
4565	#if __cplusplus >= 201103L
4566	/**
4567	* @brief Insert an initializer_list of characters.
4568	* @param __p Iterator referencing location in string to insert at.
4569	* @param __l The initializer_list of characters to insert.
4570	* @throw std::length_error If new length exceeds @c max_size().
4571	*/
4572	void
4573	insert(iterator __p, initializer_list<_CharT> __l)
4574	{
4575	_GLIBCXX_DEBUG_PEDASSERT(__p >= _M_ibegin() && __p <= _M_iend());
4576	this->insert(__p - _M_ibegin(), __l.begin(), __l.size());
4577	}
4578	#endif // C++11
4579
4580	/**
4581	* @brief Insert value of a string.
4582	* @param __pos1 Position in string to insert at.
4583	* @param __str The string to insert.
4584	* @return Reference to this string.
4585	* @throw std::length_error If new length exceeds @c max_size().
4586	*
4587	* Inserts value of @a __str starting at @a __pos1. If adding
4588	* characters causes the length to exceed max_size(),
4589	* length_error is thrown. The value of the string doesn't
4590	* change if an error is thrown.
4591	*/
4592	basic_string&
4593	insert(size_type __pos1, const basic_string& __str)
4594	{ return this->insert(__pos1, __str, size_type(`0`), __str.size()); }
4595
4596	/**
4597	* @brief Insert a substring.
4598	* @param __pos1 Position in string to insert at.
4599	* @param __str The string to insert.
4600	* @param __pos2 Start of characters in str to insert.
4601	* @param __n Number of characters to insert.
4602	* @return Reference to this string.
4603	* @throw std::length_error If new length exceeds @c max_size().
4604	* @throw std::out_of_range If @a pos1 > size() or
4605	* @a __pos2 > @a str.size().
4606	*
4607	* Starting at @a pos1, insert @a __n character of @a __str
4608	* beginning with @a __pos2. If adding characters causes the
4609	* length to exceed max_size(), length_error is thrown. If @a
4610	* __pos1 is beyond the end of this string or @a __pos2 is
4611	* beyond the end of @a __str, out_of_range is thrown. The
4612	* value of the string doesn't change if an error is thrown.
4613	*/
4614	basic_string&
4615	insert(size_type __pos1, const basic_string& __str,
4616	size_type __pos2, size_type __n = npos)
4617	{ return this->insert(__pos1, __str._M_data()
4618	+ __str._M_check(__pos2, "basic_string::insert"),
4619	__str._M_limit(__pos2, __n)); }
4620
4621	/**
4622	* @brief Insert a C substring.
4623	* @param __pos Position in string to insert at.
4624	* @param __s The C string to insert.
4625	* @param __n The number of characters to insert.
4626	* @return Reference to this string.
4627	* @throw std::length_error If new length exceeds @c max_size().
4628	* @throw std::out_of_range If @a __pos is beyond the end of this
4629	* string.
4630	*
4631	* Inserts the first @a __n characters of @a __s starting at @a
4632	* __pos. If adding characters causes the length to exceed
4633	* max_size(), length_error is thrown. If @a __pos is beyond
4634	* end(), out_of_range is thrown. The value of the string
4635	* doesn't change if an error is thrown.
4636	*/
4637	basic_string&
4638	insert(size_type __pos, const _CharT* __s, size_type __n);
4639
4640	/**
4641	* @brief Insert a C string.
4642	* @param __pos Position in string to insert at.
4643	* @param __s The C string to insert.
4644	* @return Reference to this string.
4645	* @throw std::length_error If new length exceeds @c max_size().
4646	* @throw std::out_of_range If @a pos is beyond the end of this
4647	* string.
4648	*
4649	* Inserts the first @a n characters of @a __s starting at @a __pos. If
4650	* adding characters causes the length to exceed max_size(),
4651	* length_error is thrown. If @a __pos is beyond end(), out_of_range is
4652	* thrown. The value of the string doesn't change if an error is
4653	* thrown.
4654	*/
4655	basic_string&
4656	insert(size_type __pos, const _CharT* __s)
4657	{
4658	__glibcxx_requires_string(__s);
4659	return this->insert(__pos, __s, traits_type::length(__s));
4660	}
4661
4662	/**
4663	* @brief Insert multiple characters.
4664	* @param __pos Index in string to insert at.
4665	* @param __n Number of characters to insert
4666	* @param __c The character to insert.
4667	* @return Reference to this string.
4668	* @throw std::length_error If new length exceeds @c max_size().
4669	* @throw std::out_of_range If @a __pos is beyond the end of this
4670	* string.
4671	*
4672	* Inserts @a __n copies of character @a __c starting at index
4673	* @a __pos. If adding characters causes the length to exceed
4674	* max_size(), length_error is thrown. If @a __pos > length(),
4675	* out_of_range is thrown. The value of the string doesn't
4676	* change if an error is thrown.
4677	*/
4678	basic_string&
4679	insert(size_type __pos, size_type __n, _CharT __c)
4680	{ return _M_replace_aux(_M_check(__pos, "basic_string::insert"),
4681	size_type(`0`), __n, __c); }
4682
4683	/**
4684	* @brief Insert one character.
4685	* @param __p Iterator referencing position in string to insert at.
4686	* @param __c The character to insert.
4687	* @return Iterator referencing newly inserted char.
4688	* @throw std::length_error If new length exceeds @c max_size().
4689	*
4690	* Inserts character @a __c at position referenced by @a __p.
4691	* If adding character causes the length to exceed max_size(),
4692	* length_error is thrown. If @a __p is beyond end of string,
4693	* out_of_range is thrown. The value of the string doesn't
4694	* change if an error is thrown.
4695	*/
4696	iterator
4697	insert(iterator __p, _CharT __c)
4698	{
4699	_GLIBCXX_DEBUG_PEDASSERT(__p >= _M_ibegin() && __p <= _M_iend());
4700	const size_type __pos = __p - _M_ibegin();
4701	_M_replace_aux(__pos, size_type(`0`), size_type(`1`), __c);
4702	_M_rep()->_M_set_leaked();
4703	return iterator(_M_data() + __pos);
4704	}
4705
4706	#if __cplusplus >= 201703L
4707	/**
4708	* @brief Insert a string_view.
4709	* @param __pos Position in string to insert at.
4710	* @param __svt The object convertible to string_view to insert.
4711	* @return Reference to this string.
4712	*/
4713	template<typename _Tp>
4714	_If_sv<_Tp, basic_string&>
4715	insert(size_type __pos, const _Tp& __svt)
4716	{
4717	__sv_type __sv = __svt;
4718	return this->insert(__pos, __sv.data(), __sv.size());
4719	}
4720
4721	/**
4722	* @brief Insert a string_view.
4723	* @param __pos1 Position in string to insert at.
4724	* @param __svt The object convertible to string_view to insert from.
4725	* @param __pos2 Position in string_view to insert from.
4726	* @param __n The number of characters to insert.
4727	* @return Reference to this string.
4728	*/
4729	template<typename _Tp>
4730	_If_sv<_Tp, basic_string&>
4731	insert(size_type __pos1, const _Tp& __svt,
4732	size_type __pos2, size_type __n = npos)
4733	{
4734	__sv_type __sv = __svt;
4735	return this->replace(__pos1, size_type(`0`), __sv.data()
4736	+ std::__sv_check(__sv.size(), __pos2, "basic_string::insert"),
4737	std::__sv_limit(__sv.size(), __pos2, __n));
4738	}
4739	#endif // C++17
4740
4741	/**
4742	* @brief Remove characters.
4743	* @param __pos Index of first character to remove (default 0).
4744	* @param __n Number of characters to remove (default remainder).
4745	* @return Reference to this string.
4746	* @throw std::out_of_range If @a pos is beyond the end of this
4747	* string.
4748	*
4749	* Removes @a __n characters from this string starting at @a
4750	* __pos. The length of the string is reduced by @a __n. If
4751	* there are < @a __n characters to remove, the remainder of
4752	* the string is truncated. If @a __p is beyond end of string,
4753	* out_of_range is thrown. The value of the string doesn't
4754	* change if an error is thrown.
4755	*/
4756	basic_string&
4757	erase(size_type __pos = `0`, size_type __n = npos)
4758	{
4759	_M_mutate(_M_check(__pos, "basic_string::erase"),
4760	_M_limit(__pos, __n), size_type(`0`));
4761	return *this;
4762	}
4763
4764	/**
4765	* @brief Remove one character.
4766	* @param __position Iterator referencing the character to remove.
4767	* @return iterator referencing same location after removal.
4768	*
4769	* Removes the character at @a __position from this string. The value
4770	* of the string doesn't change if an error is thrown.
4771	*/
4772	iterator
4773	erase(iterator __position)
4774	{
4775	_GLIBCXX_DEBUG_PEDASSERT(__position >= _M_ibegin()
4776	&& __position < _M_iend());
4777	const size_type __pos = __position - _M_ibegin();
4778	_M_mutate(__pos, size_type(`1`), size_type(`0`));
4779	_M_rep()->_M_set_leaked();
4780	return iterator(_M_data() + __pos);
4781	}
4782
4783	/**
4784	* @brief Remove a range of characters.
4785	* @param __first Iterator referencing the first character to remove.
4786	* @param __last Iterator referencing the end of the range.
4787	* @return Iterator referencing location of first after removal.
4788	*
4789	* Removes the characters in the range [first,last) from this string.
4790	* The value of the string doesn't change if an error is thrown.
4791	*/
4792	iterator
4793	erase(iterator __first, iterator __last);
4794
4795	#if __cplusplus >= 201103L
4796	/**
4797	* @brief Remove the last character.
4798	*
4799	* The string must be non-empty.
4800	*/
4801	void
4802	pop_back() // FIXME C++11: should be noexcept.
4803	{
4804	__glibcxx_assert(!empty());
4805	erase(size() - `1`, `1`);
4806	}
4807	#endif // C++11
4808
4809	/**
4810	* @brief Replace characters with value from another string.
4811	* @param __pos Index of first character to replace.
4812	* @param __n Number of characters to be replaced.
4813	* @param __str String to insert.
4814	* @return Reference to this string.
4815	* @throw std::out_of_range If @a pos is beyond the end of this
4816	* string.
4817	* @throw std::length_error If new length exceeds @c max_size().
4818	*
4819	* Removes the characters in the range [__pos,__pos+__n) from
4820	* this string. In place, the value of @a __str is inserted.
4821	* If @a __pos is beyond end of string, out_of_range is thrown.
4822	* If the length of the result exceeds max_size(), length_error
4823	* is thrown. The value of the string doesn't change if an
4824	* error is thrown.
4825	*/
4826	basic_string&
4827	replace(size_type __pos, size_type __n, const basic_string& __str)
4828	{ return this->replace(__pos, __n, __str._M_data(), __str.size()); }
4829
4830	/**
4831	* @brief Replace characters with value from another string.
4832	* @param __pos1 Index of first character to replace.
4833	* @param __n1 Number of characters to be replaced.
4834	* @param __str String to insert.
4835	* @param __pos2 Index of first character of str to use.
4836	* @param __n2 Number of characters from str to use.
4837	* @return Reference to this string.
4838	* @throw std::out_of_range If @a __pos1 > size() or @a __pos2 >
4839	* __str.size().
4840	* @throw std::length_error If new length exceeds @c max_size().
4841	*
4842	* Removes the characters in the range [__pos1,__pos1 + n) from this
4843	* string. In place, the value of @a __str is inserted. If @a __pos is
4844	* beyond end of string, out_of_range is thrown. If the length of the
4845	* result exceeds max_size(), length_error is thrown. The value of the
4846	* string doesn't change if an error is thrown.
4847	*/
4848	basic_string&
4849	replace(size_type __pos1, size_type __n1, const basic_string& __str,
4850	size_type __pos2, size_type __n2 = npos)
4851	{ return this->replace(__pos1, __n1, __str._M_data()
4852	+ __str._M_check(__pos2, "basic_string::replace"),
4853	__str._M_limit(__pos2, __n2)); }
4854
4855	/**
4856	* @brief Replace characters with value of a C substring.
4857	* @param __pos Index of first character to replace.
4858	* @param __n1 Number of characters to be replaced.
4859	* @param __s C string to insert.
4860	* @param __n2 Number of characters from @a s to use.
4861	* @return Reference to this string.
4862	* @throw std::out_of_range If @a pos1 > size().
4863	* @throw std::length_error If new length exceeds @c max_size().
4864	*
4865	* Removes the characters in the range [__pos,__pos + __n1)
4866	* from this string. In place, the first @a __n2 characters of
4867	* @a __s are inserted, or all of @a __s if @a __n2 is too large. If
4868	* @a __pos is beyond end of string, out_of_range is thrown. If
4869	* the length of result exceeds max_size(), length_error is
4870	* thrown. The value of the string doesn't change if an error
4871	* is thrown.
4872	*/
4873	basic_string&
4874	replace(size_type __pos, size_type __n1, const _CharT* __s,
4875	size_type __n2);
4876
4877	/**
4878	* @brief Replace characters with value of a C string.
4879	* @param __pos Index of first character to replace.
4880	* @param __n1 Number of characters to be replaced.
4881	* @param __s C string to insert.
4882	* @return Reference to this string.
4883	* @throw std::out_of_range If @a pos > size().
4884	* @throw std::length_error If new length exceeds @c max_size().
4885	*
4886	* Removes the characters in the range [__pos,__pos + __n1)
4887	* from this string. In place, the characters of @a __s are
4888	* inserted. If @a __pos is beyond end of string, out_of_range
4889	* is thrown. If the length of result exceeds max_size(),
4890	* length_error is thrown. The value of the string doesn't
4891	* change if an error is thrown.
4892	*/
4893	basic_string&
4894	replace(size_type __pos, size_type __n1, const _CharT* __s)
4895	{
4896	__glibcxx_requires_string(__s);
4897	return this->replace(__pos, __n1, __s, traits_type::length(__s));
4898	}
4899
4900	/**
4901	* @brief Replace characters with multiple characters.
4902	* @param __pos Index of first character to replace.
4903	* @param __n1 Number of characters to be replaced.
4904	* @param __n2 Number of characters to insert.
4905	* @param __c Character to insert.
4906	* @return Reference to this string.
4907	* @throw std::out_of_range If @a __pos > size().
4908	* @throw std::length_error If new length exceeds @c max_size().
4909	*
4910	* Removes the characters in the range [pos,pos + n1) from this
4911	* string. In place, @a __n2 copies of @a __c are inserted.
4912	* If @a __pos is beyond end of string, out_of_range is thrown.
4913	* If the length of result exceeds max_size(), length_error is
4914	* thrown. The value of the string doesn't change if an error
4915	* is thrown.
4916	*/
4917	basic_string&
4918	replace(size_type __pos, size_type __n1, size_type __n2, _CharT __c)
4919	{ return _M_replace_aux(_M_check(__pos, "basic_string::replace"),
4920	_M_limit(__pos, __n1), __n2, __c); }
4921
4922	/**
4923	* @brief Replace range of characters with string.
4924	* @param __i1 Iterator referencing start of range to replace.
4925	* @param __i2 Iterator referencing end of range to replace.
4926	* @param __str String value to insert.
4927	* @return Reference to this string.
4928	* @throw std::length_error If new length exceeds @c max_size().
4929	*
4930	* Removes the characters in the range [__i1,__i2). In place,
4931	* the value of @a __str is inserted. If the length of result
4932	* exceeds max_size(), length_error is thrown. The value of
4933	* the string doesn't change if an error is thrown.
4934	*/
4935	basic_string&
4936	replace(iterator __i1, iterator __i2, const basic_string& __str)
4937	{ return this->replace(__i1, __i2, __str._M_data(), __str.size()); }
4938
4939	/**
4940	* @brief Replace range of characters with C substring.
4941	* @param __i1 Iterator referencing start of range to replace.
4942	* @param __i2 Iterator referencing end of range to replace.
4943	* @param __s C string value to insert.
4944	* @param __n Number of characters from s to insert.
4945	* @return Reference to this string.
4946	* @throw std::length_error If new length exceeds @c max_size().
4947	*
4948	* Removes the characters in the range [__i1,__i2). In place,
4949	* the first @a __n characters of @a __s are inserted. If the
4950	* length of result exceeds max_size(), length_error is thrown.
4951	* The value of the string doesn't change if an error is
4952	* thrown.
4953	*/
4954	basic_string&
4955	replace(iterator __i1, iterator __i2, const _CharT* __s, size_type __n)
4956	{
4957	_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
4958	&& __i2 <= _M_iend());
4959	return this->replace(__i1 - _M_ibegin(), __i2 - __i1, __s, __n);
4960	}
4961
4962	/**
4963	* @brief Replace range of characters with C string.
4964	* @param __i1 Iterator referencing start of range to replace.
4965	* @param __i2 Iterator referencing end of range to replace.
4966	* @param __s C string value to insert.
4967	* @return Reference to this string.
4968	* @throw std::length_error If new length exceeds @c max_size().
4969	*
4970	* Removes the characters in the range [__i1,__i2). In place,
4971	* the characters of @a __s are inserted. If the length of
4972	* result exceeds max_size(), length_error is thrown. The
4973	* value of the string doesn't change if an error is thrown.
4974	*/
4975	basic_string&
4976	replace(iterator __i1, iterator __i2, const _CharT* __s)
4977	{
4978	__glibcxx_requires_string(__s);
4979	return this->replace(__i1, __i2, __s, traits_type::length(__s));
4980	}
4981
4982	/**
4983	* @brief Replace range of characters with multiple characters
4984	* @param __i1 Iterator referencing start of range to replace.
4985	* @param __i2 Iterator referencing end of range to replace.
4986	* @param __n Number of characters to insert.
4987	* @param __c Character to insert.
4988	* @return Reference to this string.
4989	* @throw std::length_error If new length exceeds @c max_size().
4990	*
4991	* Removes the characters in the range [__i1,__i2). In place,
4992	* @a __n copies of @a __c are inserted. If the length of
4993	* result exceeds max_size(), length_error is thrown. The
4994	* value of the string doesn't change if an error is thrown.
4995	*/
4996	basic_string&
4997	replace(iterator __i1, iterator __i2, size_type __n, _CharT __c)
4998	{
4999	_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
5000	&& __i2 <= _M_iend());
5001	return _M_replace_aux(__i1 - _M_ibegin(), __i2 - __i1, __n, __c);
5002	}
5003
5004	/**
5005	* @brief Replace range of characters with range.
5006	* @param __i1 Iterator referencing start of range to replace.
5007	* @param __i2 Iterator referencing end of range to replace.
5008	* @param __k1 Iterator referencing start of range to insert.
5009	* @param __k2 Iterator referencing end of range to insert.
5010	* @return Reference to this string.
5011	* @throw std::length_error If new length exceeds @c max_size().
5012	*
5013	* Removes the characters in the range [__i1,__i2). In place,
5014	* characters in the range [__k1,__k2) are inserted. If the
5015	* length of result exceeds max_size(), length_error is thrown.
5016	* The value of the string doesn't change if an error is
5017	* thrown.
5018	*/
5019	template<class _InputIterator>
5020	basic_string&
5021	replace(iterator __i1, iterator __i2,
5022	_InputIterator __k1, _InputIterator __k2)
5023	{
5024	_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
5025	&& __i2 <= _M_iend());
5026	__glibcxx_requires_valid_range(__k1, __k2);
5027	typedef typename std::__is_integer<_InputIterator>::__type _Integral;
5028	return _M_replace_dispatch(__i1, __i2, __k1, __k2, _Integral());
5029	}
5030
5031	// Specializations for the common case of pointer and iterator:
5032	// useful to avoid the overhead of temporary buffering in _M_replace.
5033	basic_string&
5034	replace(iterator __i1, iterator __i2, _CharT* __k1, _CharT* __k2)
5035	{
5036	_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
5037	&& __i2 <= _M_iend());
5038	__glibcxx_requires_valid_range(__k1, __k2);
5039	return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
5040	__k1, __k2 - __k1);
5041	}
5042
5043	basic_string&
5044	replace(iterator __i1, iterator __i2,
5045	const _CharT* __k1, const _CharT* __k2)
5046	{
5047	_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
5048	&& __i2 <= _M_iend());
5049	__glibcxx_requires_valid_range(__k1, __k2);
5050	return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
5051	__k1, __k2 - __k1);
5052	}
5053
5054	basic_string&
5055	replace(iterator __i1, iterator __i2, iterator __k1, iterator __k2)
5056	{
5057	_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
5058	&& __i2 <= _M_iend());
5059	__glibcxx_requires_valid_range(__k1, __k2);
5060	return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
5061	__k1.base(), __k2 - __k1);
5062	}
5063
5064	basic_string&
5065	replace(iterator __i1, iterator __i2,
5066	const_iterator __k1, const_iterator __k2)
5067	{
5068	_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
5069	&& __i2 <= _M_iend());
5070	__glibcxx_requires_valid_range(__k1, __k2);
5071	return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
5072	__k1.base(), __k2 - __k1);
5073	}
5074
5075	#if __cplusplus >= 201103L
5076	/**
5077	* @brief Replace range of characters with initializer_list.
5078	* @param __i1 Iterator referencing start of range to replace.
5079	* @param __i2 Iterator referencing end of range to replace.
5080	* @param __l The initializer_list of characters to insert.
5081	* @return Reference to this string.
5082	* @throw std::length_error If new length exceeds @c max_size().
5083	*
5084	* Removes the characters in the range [__i1,__i2). In place,
5085	* characters in the range [__k1,__k2) are inserted. If the
5086	* length of result exceeds max_size(), length_error is thrown.
5087	* The value of the string doesn't change if an error is
5088	* thrown.
5089	*/
5090	basic_string& replace(iterator __i1, iterator __i2,
5091	initializer_list<_CharT> __l)
5092	{ return this->replace(__i1, __i2, __l.begin(), __l.end()); }
5093	#endif // C++11
5094
5095	#if __cplusplus >= 201703L
5096	/**
5097	* @brief Replace range of characters with string_view.
5098	* @param __pos The position to replace at.
5099	* @param __n The number of characters to replace.
5100	* @param __svt The object convertible to string_view to insert.
5101	* @return Reference to this string.
5102	*/
5103	template<typename _Tp>
5104	_If_sv<_Tp, basic_string&>
5105	replace(size_type __pos, size_type __n, const _Tp& __svt)
5106	{
5107	__sv_type __sv = __svt;
5108	return this->replace(__pos, __n, __sv.data(), __sv.size());
5109	}
5110
5111	/**
5112	* @brief Replace range of characters with string_view.
5113	* @param __pos1 The position to replace at.
5114	* @param __n1 The number of characters to replace.
5115	* @param __svt The object convertible to string_view to insert from.
5116	* @param __pos2 The position in the string_view to insert from.
5117	* @param __n2 The number of characters to insert.
5118	* @return Reference to this string.
5119	*/
5120	template<typename _Tp>
5121	_If_sv<_Tp, basic_string&>
5122	replace(size_type __pos1, size_type __n1, const _Tp& __svt,
5123	size_type __pos2, size_type __n2 = npos)
5124	{
5125	__sv_type __sv = __svt;
5126	return this->replace(__pos1, __n1,
5127	__sv.data()
5128	+ std::__sv_check(__sv.size(), __pos2, "basic_string::replace"),
5129	std::__sv_limit(__sv.size(), __pos2, __n2));
5130	}
5131
5132	/**
5133	* @brief Replace range of characters with string_view.
5134	* @param __i1 An iterator referencing the start position
5135	to replace at.
5136	* @param __i2 An iterator referencing the end position
5137	for the replace.
5138	* @param __svt The object convertible to string_view to insert from.
5139	* @return Reference to this string.
5140	*/
5141	template<typename _Tp>
5142	_If_sv<_Tp, basic_string&>
5143	replace(const_iterator __i1, const_iterator __i2, const _Tp& __svt)
5144	{
5145	__sv_type __sv = __svt;
5146	return this->replace(__i1 - begin(), __i2 - __i1, __sv);
5147	}
5148	#endif // C++17
5149
5150	private:
5151	template<class _Integer>
5152	basic_string&
5153	_M_replace_dispatch(iterator __i1, iterator __i2, _Integer __n,
5154	_Integer __val, __true_type)
5155	{ return _M_replace_aux(__i1 - _M_ibegin(), __i2 - __i1, __n, __val); }
5156
5157	template<class _InputIterator>
5158	basic_string&
5159	_M_replace_dispatch(iterator __i1, iterator __i2, _InputIterator __k1,
5160	_InputIterator __k2, __false_type);
5161
5162	basic_string&
5163	_M_replace_aux(size_type __pos1, size_type __n1, size_type __n2,
5164	_CharT __c);
5165
5166	basic_string&
5167	_M_replace_safe(size_type __pos1, size_type __n1, const _CharT* __s,
5168	size_type __n2);
5169
5170	// _S_construct_aux is used to implement the 21.3.1 para 15 which
5171	// requires special behaviour if _InIter is an integral type
5172	template<class _InIterator>
5173	static _CharT*
5174	_S_construct_aux(_InIterator __beg, _InIterator __end,
5175	const _Alloc& __a, __false_type)
5176	{
5177	typedef typename iterator_traits<_InIterator>::iterator_category _Tag;
5178	return _S_construct(__beg, __end, __a, _Tag());
5179	}
5180
5181	// _GLIBCXX_RESOLVE_LIB_DEFECTS
5182	// 438. Ambiguity in the "do the right thing" clause
5183	template<class _Integer>
5184	static _CharT*
5185	_S_construct_aux(_Integer __beg, _Integer __end,
5186	const _Alloc& __a, __true_type)
5187	{ return _S_construct_aux_2(static_cast<size_type>(__beg),
5188	__end, __a); }
5189
5190	static _CharT*
5191	_S_construct_aux_2(size_type __req, _CharT __c, const _Alloc& __a)
5192	{ return _S_construct(__req, __c, __a); }
5193
5194	template<class _InIterator>
5195	static _CharT*
5196	_S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a)
5197	{
5198	typedef typename std::__is_integer<_InIterator>::__type _Integral;
5199	return _S_construct_aux(__beg, __end, __a, _Integral());
5200	}
5201
5202	// For Input Iterators, used in istreambuf_iterators, etc.
5203	template<class _InIterator>
5204	static _CharT*
5205	_S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a,
5206	input_iterator_tag);
5207
5208	// For forward_iterators up to random_access_iterators, used for
5209	// string::iterator, _CharT, etc.*
5210	template<class _FwdIterator>
5211	static _CharT*
5212	_S_construct(_FwdIterator __beg, _FwdIterator __end, const _Alloc& __a,
5213	forward_iterator_tag);
5214
5215	static _CharT*
5216	_S_construct(size_type __req, _CharT __c, const _Alloc& __a);
5217
5218	public:
5219
5220	/**
5221	* @brief Copy substring into C string.
5222	* @param __s C string to copy value into.
5223	* @param __n Number of characters to copy.
5224	* @param __pos Index of first character to copy.
5225	* @return Number of characters actually copied
5226	* @throw std::out_of_range If __pos > size().
5227	*
5228	* Copies up to @a __n characters starting at @a __pos into the
5229	* C string @a __s. If @a __pos is %greater than size(),
5230	* out_of_range is thrown.
5231	*/
5232	size_type
5233	copy(_CharT* __s, size_type __n, size_type __pos = `0`) const;
5234
5235	/**
5236	* @brief Swap contents with another string.
5237	* @param __s String to swap with.
5238	*
5239	* Exchanges the contents of this string with that of @a __s in constant
5240	* time.
5241	*/
5242	void
5243	swap(basic_string& __s)
5244	_GLIBCXX_NOEXCEPT_IF(allocator_traits<_Alloc>::is_always_equal::value);
5245
5246	// String operations:
5247	/**
5248	* @brief Return const pointer to null-terminated contents.
5249	*
5250	* This is a handle to internal data. Do not modify or dire things may
5251	* happen.
5252	*/
5253	const _CharT*
5254	c_str() const _GLIBCXX_NOEXCEPT
5255	{ return _M_data(); }
5256
5257	/**
5258	* @brief Return const pointer to contents.
5259	*
5260	* This is a pointer to internal data. It is undefined to modify
5261	* the contents through the returned pointer. To get a pointer that
5262	* allows modifying the contents use @c &str[0] instead,
5263	* (or in C++17 the non-const @c str.data() overload).
5264	*/
5265	const _CharT*
5266	data() const _GLIBCXX_NOEXCEPT
5267	{ return _M_data(); }
5268
5269	#if __cplusplus >= 201703L
5270	/**
5271	* @brief Return non-const pointer to contents.
5272	*
5273	* This is a pointer to the character sequence held by the string.
5274	* Modifying the characters in the sequence is allowed.
5275	*/
5276	_CharT*
5277	data() noexcept
5278	{
5279	_M_leak();
5280	return _M_data();
5281	}
5282	#endif
5283
5284	/**
5285	* @brief Return copy of allocator used to construct this string.
5286	*/
5287	allocator_type
5288	get_allocator() const _GLIBCXX_NOEXCEPT
5289	{ return _M_dataplus; }
5290
5291	/**
5292	* @brief Find position of a C substring.
5293	* @param __s C string to locate.
5294	* @param __pos Index of character to search from.
5295	* @param __n Number of characters from @a s to search for.
5296	* @return Index of start of first occurrence.
5297	*
5298	* Starting from @a __pos, searches forward for the first @a
5299	* __n characters in @a __s within this string. If found,
5300	* returns the index where it begins. If not found, returns
5301	* npos.
5302	*/
5303	size_type
5304	find(const _CharT* __s, size_type __pos, size_type __n) const
5305	_GLIBCXX_NOEXCEPT;
5306
5307	/**
5308	* @brief Find position of a string.
5309	* @param __str String to locate.
5310	* @param __pos Index of character to search from (default 0).
5311	* @return Index of start of first occurrence.
5312	*
5313	* Starting from @a __pos, searches forward for value of @a __str within
5314	* this string. If found, returns the index where it begins. If not
5315	* found, returns npos.
5316	*/
5317	size_type
5318	find(const basic_string& __str, size_type __pos = `0`) const
5319	_GLIBCXX_NOEXCEPT
5320	{ return this->find(__str.data(), __pos, __str.size()); }
5321
5322	/**
5323	* @brief Find position of a C string.
5324	* @param __s C string to locate.
5325	* @param __pos Index of character to search from (default 0).
5326	* @return Index of start of first occurrence.
5327	*
5328	* Starting from @a __pos, searches forward for the value of @a
5329	* __s within this string. If found, returns the index where
5330	* it begins. If not found, returns npos.
5331	*/
5332	size_type
5333	find(const _CharT* __s, size_type __pos = `0`) const _GLIBCXX_NOEXCEPT
5334	{
5335	__glibcxx_requires_string(__s);
5336	return this->find(__s, __pos, traits_type::length(__s));
5337	}
5338
5339	/**
5340	* @brief Find position of a character.
5341	* @param __c Character to locate.
5342	* @param __pos Index of character to search from (default 0).
5343	* @return Index of first occurrence.
5344	*
5345	* Starting from @a __pos, searches forward for @a __c within
5346	* this string. If found, returns the index where it was
5347	* found. If not found, returns npos.
5348	*/
5349	size_type
5350	find(_CharT __c, size_type __pos = `0`) const _GLIBCXX_NOEXCEPT;
5351
5352	#if __cplusplus >= 201703L
5353	/**
5354	* @brief Find position of a string_view.
5355	* @param __svt The object convertible to string_view to locate.
5356	* @param __pos Index of character to search from (default 0).
5357	* @return Index of start of first occurrence.
5358	*/
5359	template<typename _Tp>
5360	_If_sv<_Tp, size_type>
5361	find(const _Tp& __svt, size_type __pos = `0`) const
5362	noexcept(is_same<_Tp, __sv_type>::value)
5363	{
5364	__sv_type __sv = __svt;
5365	return this->find(__sv.data(), __pos, __sv.size());
5366	}
5367	#endif // C++17
5368
5369	/**
5370	* @brief Find last position of a string.
5371	* @param __str String to locate.
5372	* @param __pos Index of character to search back from (default end).
5373	* @return Index of start of last occurrence.
5374	*
5375	* Starting from @a __pos, searches backward for value of @a
5376	* __str within this string. If found, returns the index where
5377	* it begins. If not found, returns npos.
5378	*/
5379	size_type
5380	rfind(const basic_string& __str, size_type __pos = npos) const
5381	_GLIBCXX_NOEXCEPT
5382	{ return this->rfind(__str.data(), __pos, __str.size()); }
5383
5384	/**
5385	* @brief Find last position of a C substring.
5386	* @param __s C string to locate.
5387	* @param __pos Index of character to search back from.
5388	* @param __n Number of characters from s to search for.
5389	* @return Index of start of last occurrence.
5390	*
5391	* Starting from @a __pos, searches backward for the first @a
5392	* __n characters in @a __s within this string. If found,
5393	* returns the index where it begins. If not found, returns
5394	* npos.
5395	*/
5396	size_type
5397	rfind(const _CharT* __s, size_type __pos, size_type __n) const
5398	_GLIBCXX_NOEXCEPT;
5399
5400	/**
5401	* @brief Find last position of a C string.
5402	* @param __s C string to locate.
5403	* @param __pos Index of character to start search at (default end).
5404	* @return Index of start of last occurrence.
5405	*
5406	* Starting from @a __pos, searches backward for the value of
5407	* @a __s within this string. If found, returns the index
5408	* where it begins. If not found, returns npos.
5409	*/
5410	size_type
5411	rfind(const _CharT* __s, size_type __pos = npos) const _GLIBCXX_NOEXCEPT
5412	{
5413	__glibcxx_requires_string(__s);
5414	return this->rfind(__s, __pos, traits_type::length(__s));
5415	}
5416
5417	/**
5418	* @brief Find last position of a character.
5419	* @param __c Character to locate.
5420	* @param __pos Index of character to search back from (default end).
5421	* @return Index of last occurrence.
5422	*
5423	* Starting from @a __pos, searches backward for @a __c within
5424	* this string. If found, returns the index where it was
5425	* found. If not found, returns npos.
5426	*/
5427	size_type
5428	rfind(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT;
5429
5430	#if __cplusplus >= 201703L
5431	/**
5432	* @brief Find last position of a string_view.
5433	* @param __svt The object convertible to string_view to locate.
5434	* @param __pos Index of character to search back from (default end).
5435	* @return Index of start of last occurrence.
5436	*/
5437	template<typename _Tp>
5438	_If_sv<_Tp, size_type>
5439	rfind(const _Tp& __svt, size_type __pos = npos) const
5440	noexcept(is_same<_Tp, __sv_type>::value)
5441	{
5442	__sv_type __sv = __svt;
5443	return this->rfind(__sv.data(), __pos, __sv.size());
5444	}
5445	#endif // C++17
5446
5447	/**
5448	* @brief Find position of a character of string.
5449	* @param __str String containing characters to locate.
5450	* @param __pos Index of character to search from (default 0).
5451	* @return Index of first occurrence.
5452	*
5453	* Starting from @a __pos, searches forward for one of the
5454	* characters of @a __str within this string. If found,
5455	* returns the index where it was found. If not found, returns
5456	* npos.
5457	*/
5458	size_type
5459	find_first_of(const basic_string& __str, size_type __pos = `0`) const
5460	_GLIBCXX_NOEXCEPT
5461	{ return this->find_first_of(__str.data(), __pos, __str.size()); }
5462
5463	/**
5464	* @brief Find position of a character of C substring.
5465	* @param __s String containing characters to locate.
5466	* @param __pos Index of character to search from.
5467	* @param __n Number of characters from s to search for.
5468	* @return Index of first occurrence.
5469	*
5470	* Starting from @a __pos, searches forward for one of the
5471	* first @a __n characters of @a __s within this string. If
5472	* found, returns the index where it was found. If not found,
5473	* returns npos.
5474	*/
5475	size_type
5476	find_first_of(const _CharT* __s, size_type __pos, size_type __n) const
5477	_GLIBCXX_NOEXCEPT;
5478
5479	/**
5480	* @brief Find position of a character of C string.
5481	* @param __s String containing characters to locate.
5482	* @param __pos Index of character to search from (default 0).
5483	* @return Index of first occurrence.
5484	*
5485	* Starting from @a __pos, searches forward for one of the
5486	* characters of @a __s within this string. If found, returns
5487	* the index where it was found. If not found, returns npos.
5488	*/
5489	size_type
5490	find_first_of(const _CharT* __s, size_type __pos = `0`) const
5491	_GLIBCXX_NOEXCEPT
5492	{
5493	__glibcxx_requires_string(__s);
5494	return this->find_first_of(__s, __pos, traits_type::length(__s));
5495	}
5496
5497	/**
5498	* @brief Find position of a character.
5499	* @param __c Character to locate.
5500	* @param __pos Index of character to search from (default 0).
5501	* @return Index of first occurrence.
5502	*
5503	* Starting from @a __pos, searches forward for the character
5504	* @a __c within this string. If found, returns the index
5505	* where it was found. If not found, returns npos.
5506	*
5507	* Note: equivalent to find(__c, __pos).
5508	*/
5509	size_type
5510	find_first_of(_CharT __c, size_type __pos = `0`) const _GLIBCXX_NOEXCEPT
5511	{ return this->find(__c, __pos); }
5512
5513	#if __cplusplus >= 201703L
5514	/**
5515	* @brief Find position of a character of a string_view.
5516	* @param __svt An object convertible to string_view containing
5517	* characters to locate.
5518	* @param __pos Index of character to search from (default 0).
5519	* @return Index of first occurrence.
5520	*/
5521	template<typename _Tp>
5522	_If_sv<_Tp, size_type>
5523	find_first_of(const _Tp& __svt, size_type __pos = `0`) const
5524	noexcept(is_same<_Tp, __sv_type>::value)
5525	{
5526	__sv_type __sv = __svt;
5527	return this->find_first_of(__sv.data(), __pos, __sv.size());
5528	}
5529	#endif // C++17
5530
5531	/**
5532	* @brief Find last position of a character of string.
5533	* @param __str String containing characters to locate.
5534	* @param __pos Index of character to search back from (default end).
5535	* @return Index of last occurrence.
5536	*
5537	* Starting from @a __pos, searches backward for one of the
5538	* characters of @a __str within this string. If found,
5539	* returns the index where it was found. If not found, returns
5540	* npos.
5541	*/
5542	size_type
5543	find_last_of(const basic_string& __str, size_type __pos = npos) const
5544	_GLIBCXX_NOEXCEPT
5545	{ return this->find_last_of(__str.data(), __pos, __str.size()); }
5546
5547	/**
5548	* @brief Find last position of a character of C substring.
5549	* @param __s C string containing characters to locate.
5550	* @param __pos Index of character to search back from.
5551	* @param __n Number of characters from s to search for.
5552	* @return Index of last occurrence.
5553	*
5554	* Starting from @a __pos, searches backward for one of the
5555	* first @a __n characters of @a __s within this string. If
5556	* found, returns the index where it was found. If not found,
5557	* returns npos.
5558	*/
5559	size_type
5560	find_last_of(const _CharT* __s, size_type __pos, size_type __n) const
5561	_GLIBCXX_NOEXCEPT;
5562
5563	/**
5564	* @brief Find last position of a character of C string.
5565	* @param __s C string containing characters to locate.
5566	* @param __pos Index of character to search back from (default end).
5567	* @return Index of last occurrence.
5568	*
5569	* Starting from @a __pos, searches backward for one of the
5570	* characters of @a __s within this string. If found, returns
5571	* the index where it was found. If not found, returns npos.
5572	*/
5573	size_type
5574	find_last_of(const _CharT* __s, size_type __pos = npos) const
5575	_GLIBCXX_NOEXCEPT
5576	{
5577	__glibcxx_requires_string(__s);
5578	return this->find_last_of(__s, __pos, traits_type::length(__s));
5579	}
5580
5581	/**
5582	* @brief Find last position of a character.
5583	* @param __c Character to locate.
5584	* @param __pos Index of character to search back from (default end).
5585	* @return Index of last occurrence.
5586	*
5587	* Starting from @a __pos, searches backward for @a __c within
5588	* this string. If found, returns the index where it was
5589	* found. If not found, returns npos.
5590	*
5591	* Note: equivalent to rfind(__c, __pos).
5592	*/
5593	size_type
5594	find_last_of(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT
5595	{ return this->rfind(__c, __pos); }
5596
5597	#if __cplusplus >= 201703L
5598	/**
5599	* @brief Find last position of a character of string.
5600	* @param __svt An object convertible to string_view containing
5601	* characters to locate.
5602	* @param __pos Index of character to search back from (default end).
5603	* @return Index of last occurrence.
5604	*/
5605	template<typename _Tp>
5606	_If_sv<_Tp, size_type>
5607	find_last_of(const _Tp& __svt, size_type __pos = npos) const
5608	noexcept(is_same<_Tp, __sv_type>::value)
5609	{
5610	__sv_type __sv = __svt;
5611	return this->find_last_of(__sv.data(), __pos, __sv.size());
5612	}
5613	#endif // C++17
5614
5615	/**
5616	* @brief Find position of a character not in string.
5617	* @param __str String containing characters to avoid.
5618	* @param __pos Index of character to search from (default 0).
5619	* @return Index of first occurrence.
5620	*
5621	* Starting from @a __pos, searches forward for a character not contained
5622	* in @a __str within this string. If found, returns the index where it
5623	* was found. If not found, returns npos.
5624	*/
5625	size_type
5626	find_first_not_of(const basic_string& __str, size_type __pos = `0`) const
5627	_GLIBCXX_NOEXCEPT
5628	{ return this->find_first_not_of(__str.data(), __pos, __str.size()); }
5629
5630	/**
5631	* @brief Find position of a character not in C substring.
5632	* @param __s C string containing characters to avoid.
5633	* @param __pos Index of character to search from.
5634	* @param __n Number of characters from __s to consider.
5635	* @return Index of first occurrence.
5636	*
5637	* Starting from @a __pos, searches forward for a character not
5638	* contained in the first @a __n characters of @a __s within
5639	* this string. If found, returns the index where it was
5640	* found. If not found, returns npos.
5641	*/
5642	size_type
5643	find_first_not_of(const _CharT* __s, size_type __pos,
5644	size_type __n) const _GLIBCXX_NOEXCEPT;
5645
5646	/**
5647	* @brief Find position of a character not in C string.
5648	* @param __s C string containing characters to avoid.
5649	* @param __pos Index of character to search from (default 0).
5650	* @return Index of first occurrence.
5651	*
5652	* Starting from @a __pos, searches forward for a character not
5653	* contained in @a __s within this string. If found, returns
5654	* the index where it was found. If not found, returns npos.
5655	*/
5656	size_type
5657	find_first_not_of(const _CharT* __s, size_type __pos = `0`) const
5658	_GLIBCXX_NOEXCEPT
5659	{
5660	__glibcxx_requires_string(__s);
5661	return this->find_first_not_of(__s, __pos, traits_type::length(__s));
5662	}
5663
5664	/**
5665	* @brief Find position of a different character.
5666	* @param __c Character to avoid.
5667	* @param __pos Index of character to search from (default 0).
5668	* @return Index of first occurrence.
5669	*
5670	* Starting from @a __pos, searches forward for a character
5671	* other than @a __c within this string. If found, returns the
5672	* index where it was found. If not found, returns npos.
5673	*/
5674	size_type
5675	find_first_not_of(_CharT __c, size_type __pos = `0`) const
5676	_GLIBCXX_NOEXCEPT;
5677
5678	#if __cplusplus >= 201703L
5679	/**
5680	* @brief Find position of a character not in a string_view.
5681	* @param __svt An object convertible to string_view containing
5682	* characters to avoid.
5683	* @param __pos Index of character to search from (default 0).
5684	* @return Index of first occurrence.
5685	*/
5686	template<typename _Tp>
5687	_If_sv<_Tp, size_type>
5688	find_first_not_of(const _Tp& __svt, size_type __pos = `0`) const
5689	noexcept(is_same<_Tp, __sv_type>::value)
5690	{
5691	__sv_type __sv = __svt;
5692	return this->find_first_not_of(__sv.data(), __pos, __sv.size());
5693	}
5694	#endif // C++17
5695
5696	/**
5697	* @brief Find last position of a character not in string.
5698	* @param __str String containing characters to avoid.
5699	* @param __pos Index of character to search back from (default end).
5700	* @return Index of last occurrence.
5701	*
5702	* Starting from @a __pos, searches backward for a character
5703	* not contained in @a __str within this string. If found,
5704	* returns the index where it was found. If not found, returns
5705	* npos.
5706	*/
5707	size_type
5708	find_last_not_of(const basic_string& __str, size_type __pos = npos) const
5709	_GLIBCXX_NOEXCEPT
5710	{ return this->find_last_not_of(__str.data(), __pos, __str.size()); }
5711
5712	/**
5713	* @brief Find last position of a character not in C substring.
5714	* @param __s C string containing characters to avoid.
5715	* @param __pos Index of character to search back from.
5716	* @param __n Number of characters from s to consider.
5717	* @return Index of last occurrence.
5718	*
5719	* Starting from @a __pos, searches backward for a character not
5720	* contained in the first @a __n characters of @a __s within this string.
5721	* If found, returns the index where it was found. If not found,
5722	* returns npos.
5723	*/
5724	size_type
5725	find_last_not_of(const _CharT* __s, size_type __pos,
5726	size_type __n) const _GLIBCXX_NOEXCEPT;
5727	/**
5728	* @brief Find last position of a character not in C string.
5729	* @param __s C string containing characters to avoid.
5730	* @param __pos Index of character to search back from (default end).
5731	* @return Index of last occurrence.
5732	*
5733	* Starting from @a __pos, searches backward for a character
5734	* not contained in @a __s within this string. If found,
5735	* returns the index where it was found. If not found, returns
5736	* npos.
5737	*/
5738	size_type
5739	find_last_not_of(const _CharT* __s, size_type __pos = npos) const
5740	_GLIBCXX_NOEXCEPT
5741	{
5742	__glibcxx_requires_string(__s);
5743	return this->find_last_not_of(__s, __pos, traits_type::length(__s));
5744	}
5745
5746	/**
5747	* @brief Find last position of a different character.
5748	* @param __c Character to avoid.
5749	* @param __pos Index of character to search back from (default end).
5750	* @return Index of last occurrence.
5751	*
5752	* Starting from @a __pos, searches backward for a character other than
5753	* @a __c within this string. If found, returns the index where it was
5754	* found. If not found, returns npos.
5755	*/
5756	size_type
5757	find_last_not_of(_CharT __c, size_type __pos = npos) const
5758	_GLIBCXX_NOEXCEPT;
5759
5760	#if __cplusplus >= 201703L
5761	/**
5762	* @brief Find last position of a character not in a string_view.
5763	* @param __svt An object convertible to string_view containing
5764	* characters to avoid.
5765	* @param __pos Index of character to search back from (default end).
5766	* @return Index of last occurrence.
5767	*/
5768	template<typename _Tp>
5769	_If_sv<_Tp, size_type>
5770	find_last_not_of(const _Tp& __svt, size_type __pos = npos) const
5771	noexcept(is_same<_Tp, __sv_type>::value)
5772	{
5773	__sv_type __sv = __svt;
5774	return this->find_last_not_of(__sv.data(), __pos, __sv.size());
5775	}
5776	#endif // C++17
5777
5778	/**
5779	* @brief Get a substring.
5780	* @param __pos Index of first character (default 0).
5781	* @param __n Number of characters in substring (default remainder).
5782	* @return The new string.
5783	* @throw std::out_of_range If __pos > size().
5784	*
5785	* Construct and return a new string using the @a __n
5786	* characters starting at @a __pos. If the string is too
5787	* short, use the remainder of the characters. If @a __pos is
5788	* beyond the end of the string, out_of_range is thrown.
5789	*/
5790	basic_string
5791	substr(size_type __pos = `0`, size_type __n = npos) const
5792	{ return basic_string(*this,
5793	_M_check(__pos, "basic_string::substr"), __n); }
5794
5795	/**
5796	* @brief Compare to a string.
5797	* @param __str String to compare against.
5798	* @return Integer < 0, 0, or > 0.
5799	*
5800	* Returns an integer < 0 if this string is ordered before @a
5801	* __str, 0 if their values are equivalent, or > 0 if this
5802	* string is ordered after @a __str. Determines the effective
5803	* length rlen of the strings to compare as the smallest of
5804	* size() and str.size(). The function then compares the two
5805	* strings by calling traits::compare(data(), str.data(),rlen).
5806	* If the result of the comparison is nonzero returns it,
5807	* otherwise the shorter one is ordered first.
5808	*/
5809	int
5810	compare(const basic_string& __str) const
5811	{
5812	const size_type __size = this->size();
5813	const size_type __osize = __str.size();
5814	const size_type __len = std::min(__size, __osize);
5815
5816	int __r = traits_type::compare(_M_data(), __str.data(), __len);
5817	if (!__r)
5818	__r = _S_compare(__size, __osize);
5819	return __r;
5820	}
5821
5822	#if __cplusplus >= 201703L
5823	/**
5824	* @brief Compare to a string_view.
5825	* @param __svt An object convertible to string_view to compare against.
5826	* @return Integer < 0, 0, or > 0.
5827	*/
5828	template<typename _Tp>
5829	_If_sv<_Tp, int>
5830	compare(const _Tp& __svt) const
5831	noexcept(is_same<_Tp, __sv_type>::value)
5832	{
5833	__sv_type __sv = __svt;
5834	const size_type __size = this->size();
5835	const size_type __osize = __sv.size();
5836	const size_type __len = std::min(__size, __osize);
5837
5838	int __r = traits_type::compare(_M_data(), __sv.data(), __len);
5839	if (!__r)
5840	__r = _S_compare(__size, __osize);
5841	return __r;
5842	}
5843
5844	/**
5845	* @brief Compare to a string_view.
5846	* @param __pos A position in the string to start comparing from.
5847	* @param __n The number of characters to compare.
5848	* @param __svt An object convertible to string_view to compare
5849	* against.
5850	* @return Integer < 0, 0, or > 0.
5851	*/
5852	template<typename _Tp>
5853	_If_sv<_Tp, int>
5854	compare(size_type __pos, size_type __n, const _Tp& __svt) const
5855	noexcept(is_same<_Tp, __sv_type>::value)
5856	{
5857	__sv_type __sv = __svt;
5858	return __sv_type(*this).substr(__pos, __n).compare(__sv);
5859	}
5860
5861	/**
5862	* @brief Compare to a string_view.
5863	* @param __pos1 A position in the string to start comparing from.
5864	* @param __n1 The number of characters to compare.
5865	* @param __svt An object convertible to string_view to compare
5866	* against.
5867	* @param __pos2 A position in the string_view to start comparing from.
5868	* @param __n2 The number of characters to compare.
5869	* @return Integer < 0, 0, or > 0.
5870	*/
5871	template<typename _Tp>
5872	_If_sv<_Tp, int>
5873	compare(size_type __pos1, size_type __n1, const _Tp& __svt,
5874	size_type __pos2, size_type __n2 = npos) const
5875	noexcept(is_same<_Tp, __sv_type>::value)
5876	{
5877	__sv_type __sv = __svt;
5878	return __sv_type(*this)
5879	.substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
5880	}
5881	#endif // C++17
5882
5883	/**
5884	* @brief Compare substring to a string.
5885	* @param __pos Index of first character of substring.
5886	* @param __n Number of characters in substring.
5887	* @param __str String to compare against.
5888	* @return Integer < 0, 0, or > 0.
5889	*
5890	* Form the substring of this string from the @a __n characters
5891	* starting at @a __pos. Returns an integer < 0 if the
5892	* substring is ordered before @a __str, 0 if their values are
5893	* equivalent, or > 0 if the substring is ordered after @a
5894	* __str. Determines the effective length rlen of the strings
5895	* to compare as the smallest of the length of the substring
5896	* and @a __str.size(). The function then compares the two
5897	* strings by calling
5898	* traits::compare(substring.data(),str.data(),rlen). If the
5899	* result of the comparison is nonzero returns it, otherwise
5900	* the shorter one is ordered first.
5901	*/
5902	int
5903	compare(size_type __pos, size_type __n, const basic_string& __str) const;
5904
5905	/**
5906	* @brief Compare substring to a substring.
5907	* @param __pos1 Index of first character of substring.
5908	* @param __n1 Number of characters in substring.
5909	* @param __str String to compare against.
5910	* @param __pos2 Index of first character of substring of str.
5911	* @param __n2 Number of characters in substring of str.
5912	* @return Integer < 0, 0, or > 0.
5913	*
5914	* Form the substring of this string from the @a __n1
5915	* characters starting at @a __pos1. Form the substring of @a
5916	* __str from the @a __n2 characters starting at @a __pos2.
5917	* Returns an integer < 0 if this substring is ordered before
5918	* the substring of @a __str, 0 if their values are equivalent,
5919	* or > 0 if this substring is ordered after the substring of
5920	* @a __str. Determines the effective length rlen of the
5921	* strings to compare as the smallest of the lengths of the
5922	* substrings. The function then compares the two strings by
5923	* calling
5924	* traits::compare(substring.data(),str.substr(pos2,n2).data(),rlen).
5925	* If the result of the comparison is nonzero returns it,
5926	* otherwise the shorter one is ordered first.
5927	*/
5928	int
5929	compare(size_type __pos1, size_type __n1, const basic_string& __str,
5930	size_type __pos2, size_type __n2 = npos) const;
5931
5932	/**
5933	* @brief Compare to a C string.
5934	* @param __s C string to compare against.
5935	* @return Integer < 0, 0, or > 0.
5936	*
5937	* Returns an integer < 0 if this string is ordered before @a __s, 0 if
5938	* their values are equivalent, or > 0 if this string is ordered after
5939	* @a __s. Determines the effective length rlen of the strings to
5940	* compare as the smallest of size() and the length of a string
5941	* constructed from @a __s. The function then compares the two strings
5942	* by calling traits::compare(data(),s,rlen). If the result of the
5943	* comparison is nonzero returns it, otherwise the shorter one is
5944	* ordered first.
5945	*/
5946	int
5947	compare(const _CharT* __s) const _GLIBCXX_NOEXCEPT;
5948
5949	// _GLIBCXX_RESOLVE_LIB_DEFECTS
5950	// 5 String::compare specification questionable
5951	/**
5952	* @brief Compare substring to a C string.
5953	* @param __pos Index of first character of substring.
5954	* @param __n1 Number of characters in substring.
5955	* @param __s C string to compare against.
5956	* @return Integer < 0, 0, or > 0.
5957	*
5958	* Form the substring of this string from the @a __n1
5959	* characters starting at @a pos. Returns an integer < 0 if
5960	* the substring is ordered before @a __s, 0 if their values
5961	* are equivalent, or > 0 if the substring is ordered after @a
5962	* __s. Determines the effective length rlen of the strings to
5963	* compare as the smallest of the length of the substring and
5964	* the length of a string constructed from @a __s. The
5965	* function then compares the two string by calling
5966	* traits::compare(substring.data(),__s,rlen). If the result of
5967	* the comparison is nonzero returns it, otherwise the shorter
5968	* one is ordered first.
5969	*/
5970	int
5971	compare(size_type __pos, size_type __n1, const _CharT* __s) const;
5972
5973	/**
5974	* @brief Compare substring against a character %array.
5975	* @param __pos Index of first character of substring.
5976	* @param __n1 Number of characters in substring.
5977	* @param __s character %array to compare against.
5978	* @param __n2 Number of characters of s.
5979	* @return Integer < 0, 0, or > 0.
5980	*
5981	* Form the substring of this string from the @a __n1
5982	* characters starting at @a __pos. Form a string from the
5983	* first @a __n2 characters of @a __s. Returns an integer < 0
5984	* if this substring is ordered before the string from @a __s,
5985	* 0 if their values are equivalent, or > 0 if this substring
5986	* is ordered after the string from @a __s. Determines the
5987	* effective length rlen of the strings to compare as the
5988	* smallest of the length of the substring and @a __n2. The
5989	* function then compares the two strings by calling
5990	* traits::compare(substring.data(),s,rlen). If the result of
5991	* the comparison is nonzero returns it, otherwise the shorter
5992	* one is ordered first.
5993	*
5994	* NB: s must have at least n2 characters, '\\0' has
5995	* no special meaning.
5996	*/
5997	int
5998	compare(size_type __pos, size_type __n1, const _CharT* __s,
5999	size_type __n2) const;
6000
6001	#if __cplusplus > 201703L
6002	bool
6003	starts_with(basic_string_view<_CharT, _Traits> __x) const noexcept
6004	{ return __sv_type(this->data(), this->size()).starts_with(__x); }
6005
6006	bool
6007	starts_with(_CharT __x) const noexcept
6008	{ return __sv_type(this->data(), this->size()).starts_with(__x); }
6009
6010	bool
6011	starts_with(const _CharT* __x) const noexcept
6012	{ return __sv_type(this->data(), this->size()).starts_with(__x); }
6013
6014	bool
6015	ends_with(basic_string_view<_CharT, _Traits> __x) const noexcept
6016	{ return __sv_type(this->data(), this->size()).ends_with(__x); }
6017
6018	bool
6019	ends_with(_CharT __x) const noexcept
6020	{ return __sv_type(this->data(), this->size()).ends_with(__x); }
6021
6022	bool
6023	ends_with(const _CharT* __x) const noexcept
6024	{ return __sv_type(this->data(), this->size()).ends_with(__x); }
6025	#endif // C++20
6026
6027	#if __cplusplus > 202011L
6028	bool
6029	contains(basic_string_view<_CharT, _Traits> __x) const noexcept
6030	{ return __sv_type(this->data(), this->size()).contains(__x); }
6031
6032	bool
6033	contains(_CharT __x) const noexcept
6034	{ return __sv_type(this->data(), this->size()).contains(__x); }
6035
6036	bool
6037	contains(const _CharT* __x) const noexcept
6038	{ return __sv_type(this->data(), this->size()).contains(__x); }
6039	#endif // C++23
6040
6041	# ifdef _GLIBCXX_TM_TS_INTERNAL
6042	friend void
6043	::_txnal_cow_string_C1_for_exceptions(void* that, const char* s,
6044	void* exc);
6045	friend const char*
6046	::_txnal_cow_string_c_str(const void *that);
6047	friend void
6048	::_txnal_cow_string_D1(void *that);
6049	friend void
6050	::_txnal_cow_string_D1_commit(void *that);
6051	# endif
6052	};
6053	#endif // !_GLIBCXX_USE_CXX11_ABI
6054
6055	#if __cpp_deduction_guides >= 201606
6056	_GLIBCXX_BEGIN_NAMESPACE_CXX11
6057	template<typename _InputIterator, typename _CharT
6058	= typename iterator_traits<_InputIterator>::value_type,
6059	typename _Allocator = allocator<_CharT>,
6060	typename = _RequireInputIter<_InputIterator>,
6061	typename = _RequireAllocator<_Allocator>>
6062	basic_string(_InputIterator, _InputIterator, _Allocator = _Allocator())
6063	-> basic_string<_CharT, char_traits<_CharT>, _Allocator>;
6064
6065	// _GLIBCXX_RESOLVE_LIB_DEFECTS
6066	// 3075. basic_string needs deduction guides from basic_string_view
6067	template<typename _CharT, typename _Traits,
6068	typename _Allocator = allocator<_CharT>,
6069	typename = _RequireAllocator<_Allocator>>
6070	basic_string(basic_string_view<_CharT, _Traits>, const _Allocator& = _Allocator())
6071	-> basic_string<_CharT, _Traits, _Allocator>;
6072
6073	template<typename _CharT, typename _Traits,
6074	typename _Allocator = allocator<_CharT>,
6075	typename = _RequireAllocator<_Allocator>>
6076	basic_string(basic_string_view<_CharT, _Traits>,
6077	typename basic_string<_CharT, _Traits, _Allocator>::size_type,
6078	typename basic_string<_CharT, _Traits, _Allocator>::size_type,
6079	const _Allocator& = _Allocator())
6080	-> basic_string<_CharT, _Traits, _Allocator>;
6081	_GLIBCXX_END_NAMESPACE_CXX11
6082	#endif
6083
6084	// operator+
6085	/**
6086	* @brief Concatenate two strings.
6087	* @param __lhs First string.
6088	* @param __rhs Last string.
6089	* @return New string with value of @a __lhs followed by @a __rhs.
6090	*/
6091	template<typename _CharT, typename _Traits, typename _Alloc>
6092	basic_string<_CharT, _Traits, _Alloc>
6093	operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6094	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6095	{
6096	basic_string<_CharT, _Traits, _Alloc> __str(__lhs);
6097	__str.append(__rhs);
6098	return __str;
6099	}
6100
6101	/**
6102	* @brief Concatenate C string and string.
6103	* @param __lhs First string.
6104	* @param __rhs Last string.
6105	* @return New string with value of @a __lhs followed by @a __rhs.
6106	*/
6107	template<typename _CharT, typename _Traits, typename _Alloc>
6108	basic_string<_CharT,_Traits,_Alloc>
6109	operator+(const _CharT* __lhs,
6110	const basic_string<_CharT,_Traits,_Alloc>& __rhs);
6111
6112	/**
6113	* @brief Concatenate character and string.
6114	* @param __lhs First string.
6115	* @param __rhs Last string.
6116	* @return New string with @a __lhs followed by @a __rhs.
6117	*/
6118	template<typename _CharT, typename _Traits, typename _Alloc>
6119	basic_string<_CharT,_Traits,_Alloc>
6120	operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Alloc>& __rhs);
6121
6122	/**
6123	* @brief Concatenate string and C string.
6124	* @param __lhs First string.
6125	* @param __rhs Last string.
6126	* @return New string with @a __lhs followed by @a __rhs.
6127	*/
6128	template<typename _CharT, typename _Traits, typename _Alloc>
6129	inline basic_string<_CharT, _Traits, _Alloc>
6130	operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6131	const _CharT* __rhs)
6132	{
6133	basic_string<_CharT, _Traits, _Alloc> __str(__lhs);
6134	__str.append(__rhs);
6135	return __str;
6136	}
6137
6138	/**
6139	* @brief Concatenate string and character.
6140	* @param __lhs First string.
6141	* @param __rhs Last string.
6142	* @return New string with @a __lhs followed by @a __rhs.
6143	*/
6144	template<typename _CharT, typename _Traits, typename _Alloc>
6145	inline basic_string<_CharT, _Traits, _Alloc>
6146	operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, _CharT __rhs)
6147	{
6148	typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
6149	typedef typename __string_type::size_type __size_type;
6150	__string_type __str(__lhs);
6151	__str.append(__size_type(`1`), __rhs);
6152	return __str;
6153	}
6154
6155	#if __cplusplus >= 201103L
6156	template<typename _CharT, typename _Traits, typename _Alloc>
6157	inline basic_string<_CharT, _Traits, _Alloc>
6158	operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
6159	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6160	{ return std::move(__lhs.append(__rhs)); }
6161
6162	template<typename _CharT, typename _Traits, typename _Alloc>
6163	inline basic_string<_CharT, _Traits, _Alloc>
6164	operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6165	basic_string<_CharT, _Traits, _Alloc>&& __rhs)
6166	{ return std::move(__rhs.insert(`0`, __lhs)); }
6167
6168	template<typename _CharT, typename _Traits, typename _Alloc>
6169	inline basic_string<_CharT, _Traits, _Alloc>
6170	operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
6171	basic_string<_CharT, _Traits, _Alloc>&& __rhs)
6172	{
6173	#if _GLIBCXX_USE_CXX11_ABI
6174	using _Alloc_traits = allocator_traits<_Alloc>;
6175	bool __use_rhs = false;
6176	if _GLIBCXX17_CONSTEXPR (typename _Alloc_traits::is_always_equal{})
6177	__use_rhs = true;
6178	else if (__lhs.get_allocator() == __rhs.get_allocator())
6179	__use_rhs = true;
6180	if (__use_rhs)
6181	#endif
6182	{
6183	const auto __size = __lhs.size() + __rhs.size();
6184	if (__size > __lhs.capacity() && __size <= __rhs.capacity())
6185	return std::move(__rhs.insert(`0`, __lhs));
6186	}
6187	return std::move(__lhs.append(__rhs));
6188	}
6189
6190	template<typename _CharT, typename _Traits, typename _Alloc>
6191	inline basic_string<_CharT, _Traits, _Alloc>
6192	operator+(const _CharT* __lhs,
6193	basic_string<_CharT, _Traits, _Alloc>&& __rhs)
6194	{ return std::move(__rhs.insert(`0`, __lhs)); }
6195
6196	template<typename _CharT, typename _Traits, typename _Alloc>
6197	inline basic_string<_CharT, _Traits, _Alloc>
6198	operator+(_CharT __lhs,
6199	basic_string<_CharT, _Traits, _Alloc>&& __rhs)
6200	{ return std::move(__rhs.insert(`0`, `1`, __lhs)); }
6201
6202	template<typename _CharT, typename _Traits, typename _Alloc>
6203	inline basic_string<_CharT, _Traits, _Alloc>
6204	operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
6205	const _CharT* __rhs)
6206	{ return std::move(__lhs.append(__rhs)); }
6207
6208	template<typename _CharT, typename _Traits, typename _Alloc>
6209	inline basic_string<_CharT, _Traits, _Alloc>
6210	operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
6211	_CharT __rhs)
6212	{ return std::move(__lhs.append(`1`, __rhs)); }
6213	#endif
6214
6215	// operator ==
6216	/**
6217	* @brief Test equivalence of two strings.
6218	* @param __lhs First string.
6219	* @param __rhs Second string.
6220	* @return True if @a __lhs.compare(@a __rhs) == 0. False otherwise.
6221	*/
6222	template<typename _CharT, typename _Traits, typename _Alloc>
6223	inline bool
6224	operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6225	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6226	_GLIBCXX_NOEXCEPT
6227	{ return __lhs.compare(__rhs) == `0`; }
6228
6229	template<typename _CharT>
6230	inline
6231	typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, bool>::__type
6232	operator==(const basic_string<_CharT>& __lhs,
6233	const basic_string<_CharT>& __rhs) _GLIBCXX_NOEXCEPT
6234	{ return (__lhs.size() == __rhs.size()
6235	&& !std::char_traits<_CharT>::compare(__lhs.data(), __rhs.data(),
6236	__lhs.size())); }
6237
6238	/**
6239	* @brief Test equivalence of string and C string.
6240	* @param __lhs String.
6241	* @param __rhs C string.
6242	* @return True if @a __lhs.compare(@a __rhs) == 0. False otherwise.
6243	*/
6244	template<typename _CharT, typename _Traits, typename _Alloc>
6245	inline bool
6246	operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6247	const _CharT* __rhs)
6248	{ return __lhs.compare(__rhs) == `0`; }
6249
6250	#if __cpp_lib_three_way_comparison
6251	/**
6252	* @brief Three-way comparison of a string and a C string.
6253	* @param __lhs A string.
6254	* @param __rhs A null-terminated string.
6255	* @return A value indicating whether `__lhs` is less than, equal to,
6256	* greater than, or incomparable with `__rhs`.
6257	*/
6258	template<typename _CharT, typename _Traits, typename _Alloc>
6259	inline auto
6260	operator<=>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6261	const basic_string<_CharT, _Traits, _Alloc>& __rhs) noexcept
6262	-> decltype(__detail::__char_traits_cmp_cat<_Traits>(`0`))
6263	{ return __detail::__char_traits_cmp_cat<_Traits>(__lhs.compare(__rhs)); }
6264
6265	/**
6266	* @brief Three-way comparison of a string and a C string.
6267	* @param __lhs A string.
6268	* @param __rhs A null-terminated string.
6269	* @return A value indicating whether `__lhs` is less than, equal to,
6270	* greater than, or incomparable with `__rhs`.
6271	*/
6272	template<typename _CharT, typename _Traits, typename _Alloc>
6273	inline auto
6274	operator<=>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6275	const _CharT* __rhs) noexcept
6276	-> decltype(__detail::__char_traits_cmp_cat<_Traits>(`0`))
6277	{ return __detail::__char_traits_cmp_cat<_Traits>(__lhs.compare(__rhs)); }
6278	#else
6279	/**
6280	* @brief Test equivalence of C string and string.
6281	* @param __lhs C string.
6282	* @param __rhs String.
6283	* @return True if @a __rhs.compare(@a __lhs) == 0. False otherwise.
6284	*/
6285	template<typename _CharT, typename _Traits, typename _Alloc>
6286	inline bool
6287	operator==(const _CharT* __lhs,
6288	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6289	{ return __rhs.compare(__lhs) == `0`; }
6290
6291	// operator !=
6292	/**
6293	* @brief Test difference of two strings.
6294	* @param __lhs First string.
6295	* @param __rhs Second string.
6296	* @return True if @a __lhs.compare(@a __rhs) != 0. False otherwise.
6297	*/
6298	template<typename _CharT, typename _Traits, typename _Alloc>
6299	inline bool
6300	operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6301	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6302	_GLIBCXX_NOEXCEPT
6303	{ return !(__lhs == __rhs); }
6304
6305	/**
6306	* @brief Test difference of C string and string.
6307	* @param __lhs C string.
6308	* @param __rhs String.
6309	* @return True if @a __rhs.compare(@a __lhs) != 0. False otherwise.
6310	*/
6311	template<typename _CharT, typename _Traits, typename _Alloc>
6312	inline bool
6313	operator!=(const _CharT* __lhs,
6314	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6315	{ return !(__lhs == __rhs); }
6316
6317	/**
6318	* @brief Test difference of string and C string.
6319	* @param __lhs String.
6320	* @param __rhs C string.
6321	* @return True if @a __lhs.compare(@a __rhs) != 0. False otherwise.
6322	*/
6323	template<typename _CharT, typename _Traits, typename _Alloc>
6324	inline bool
6325	operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6326	const _CharT* __rhs)
6327	{ return !(__lhs == __rhs); }
6328
6329	// operator <
6330	/**
6331	* @brief Test if string precedes string.
6332	* @param __lhs First string.
6333	* @param __rhs Second string.
6334	* @return True if @a __lhs precedes @a __rhs. False otherwise.
6335	*/
6336	template<typename _CharT, typename _Traits, typename _Alloc>
6337	inline bool
6338	operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6339	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6340	_GLIBCXX_NOEXCEPT
6341	{ return __lhs.compare(__rhs) < `0`; }
6342
6343	/**
6344	* @brief Test if string precedes C string.
6345	* @param __lhs String.
6346	* @param __rhs C string.
6347	* @return True if @a __lhs precedes @a __rhs. False otherwise.
6348	*/
6349	template<typename _CharT, typename _Traits, typename _Alloc>
6350	inline bool
6351	operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6352	const _CharT* __rhs)
6353	{ return __lhs.compare(__rhs) < `0`; }
6354
6355	/**
6356	* @brief Test if C string precedes string.
6357	* @param __lhs C string.
6358	* @param __rhs String.
6359	* @return True if @a __lhs precedes @a __rhs. False otherwise.
6360	*/
6361	template<typename _CharT, typename _Traits, typename _Alloc>
6362	inline bool
6363	operator<(const _CharT* __lhs,
6364	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6365	{ return __rhs.compare(__lhs) > `0`; }
6366
6367	// operator >
6368	/**
6369	* @brief Test if string follows string.
6370	* @param __lhs First string.
6371	* @param __rhs Second string.
6372	* @return True if @a __lhs follows @a __rhs. False otherwise.
6373	*/
6374	template<typename _CharT, typename _Traits, typename _Alloc>
6375	inline bool
6376	operator>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6377	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6378	_GLIBCXX_NOEXCEPT
6379	{ return __lhs.compare(__rhs) > `0`; }
6380
6381	/**
6382	* @brief Test if string follows C string.
6383	* @param __lhs String.
6384	* @param __rhs C string.
6385	* @return True if @a __lhs follows @a __rhs. False otherwise.
6386	*/
6387	template<typename _CharT, typename _Traits, typename _Alloc>
6388	inline bool
6389	operator>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6390	const _CharT* __rhs)
6391	{ return __lhs.compare(__rhs) > `0`; }
6392
6393	/**
6394	* @brief Test if C string follows string.
6395	* @param __lhs C string.
6396	* @param __rhs String.
6397	* @return True if @a __lhs follows @a __rhs. False otherwise.
6398	*/
6399	template<typename _CharT, typename _Traits, typename _Alloc>
6400	inline bool
6401	operator>(const _CharT* __lhs,
6402	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6403	{ return __rhs.compare(__lhs) < `0`; }
6404
6405	// operator <=
6406	/**
6407	* @brief Test if string doesn't follow string.
6408	* @param __lhs First string.
6409	* @param __rhs Second string.
6410	* @return True if @a __lhs doesn't follow @a __rhs. False otherwise.
6411	*/
6412	template<typename _CharT, typename _Traits, typename _Alloc>
6413	inline bool
6414	operator<=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6415	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6416	_GLIBCXX_NOEXCEPT
6417	{ return __lhs.compare(__rhs) <= `0`; }
6418
6419	/**
6420	* @brief Test if string doesn't follow C string.
6421	* @param __lhs String.
6422	* @param __rhs C string.
6423	* @return True if @a __lhs doesn't follow @a __rhs. False otherwise.
6424	*/
6425	template<typename _CharT, typename _Traits, typename _Alloc>
6426	inline bool
6427	operator<=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6428	const _CharT* __rhs)
6429	{ return __lhs.compare(__rhs) <= `0`; }
6430
6431	/**
6432	* @brief Test if C string doesn't follow string.
6433	* @param __lhs C string.
6434	* @param __rhs String.
6435	* @return True if @a __lhs doesn't follow @a __rhs. False otherwise.
6436	*/
6437	template<typename _CharT, typename _Traits, typename _Alloc>
6438	inline bool
6439	operator<=(const _CharT* __lhs,
6440	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6441	{ return __rhs.compare(__lhs) >= `0`; }
6442
6443	// operator >=
6444	/**
6445	* @brief Test if string doesn't precede string.
6446	* @param __lhs First string.
6447	* @param __rhs Second string.
6448	* @return True if @a __lhs doesn't precede @a __rhs. False otherwise.
6449	*/
6450	template<typename _CharT, typename _Traits, typename _Alloc>
6451	inline bool
6452	operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6453	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6454	_GLIBCXX_NOEXCEPT
6455	{ return __lhs.compare(__rhs) >= `0`; }
6456
6457	/**
6458	* @brief Test if string doesn't precede C string.
6459	* @param __lhs String.
6460	* @param __rhs C string.
6461	* @return True if @a __lhs doesn't precede @a __rhs. False otherwise.
6462	*/
6463	template<typename _CharT, typename _Traits, typename _Alloc>
6464	inline bool
6465	operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6466	const _CharT* __rhs)
6467	{ return __lhs.compare(__rhs) >= `0`; }
6468
6469	/**
6470	* @brief Test if C string doesn't precede string.
6471	* @param __lhs C string.
6472	* @param __rhs String.
6473	* @return True if @a __lhs doesn't precede @a __rhs. False otherwise.
6474	*/
6475	template<typename _CharT, typename _Traits, typename _Alloc>
6476	inline bool
6477	operator>=(const _CharT* __lhs,
6478	const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6479	{ return __rhs.compare(__lhs) <= `0`; }
6480	#endif // three-way comparison
6481
6482	/**
6483	* @brief Swap contents of two strings.
6484	* @param __lhs First string.
6485	* @param __rhs Second string.
6486	*
6487	* Exchanges the contents of @a __lhs and @a __rhs in constant time.
6488	*/
6489	template<typename _CharT, typename _Traits, typename _Alloc>
6490	inline void
6491	swap(basic_string<_CharT, _Traits, _Alloc>& __lhs,
6492	basic_string<_CharT, _Traits, _Alloc>& __rhs)
6493	_GLIBCXX_NOEXCEPT_IF(noexcept(__lhs.swap(__rhs)))
6494	{ __lhs.swap(__rhs); }
6495
6496
6497	/**
6498	* @brief Read stream into a string.
6499	* @param __is Input stream.
6500	* @param __str Buffer to store into.
6501	* @return Reference to the input stream.
6502	*
6503	* Stores characters from @a __is into @a __str until whitespace is
6504	* found, the end of the stream is encountered, or str.max_size()
6505	* is reached. If is.width() is non-zero, that is the limit on the
6506	* number of characters stored into @a __str. Any previous
6507	* contents of @a __str are erased.
6508	*/
6509	template<typename _CharT, typename _Traits, typename _Alloc>
6510	basic_istream<_CharT, _Traits>&
6511	operator>>(basic_istream<_CharT, _Traits>& __is,
6512	basic_string<_CharT, _Traits, _Alloc>& __str);
6513
6514	template<>
6515	basic_istream<char>&
6516	operator>>(basic_istream<char>& __is, basic_string<char>& __str);
6517
6518	/**
6519	* @brief Write string to a stream.
6520	* @param __os Output stream.
6521	* @param __str String to write out.
6522	* @return Reference to the output stream.
6523	*
6524	* Output characters of @a __str into os following the same rules as for
6525	* writing a C string.
6526	*/
6527	template<typename _CharT, typename _Traits, typename _Alloc>
6528	inline basic_ostream<_CharT, _Traits>&
6529	operator<<(basic_ostream<_CharT, _Traits>& __os,
6530	const basic_string<_CharT, _Traits, _Alloc>& __str)
6531	{
6532	// _GLIBCXX_RESOLVE_LIB_DEFECTS
6533	// 586. string inserter not a formatted function
6534	return __ostream_insert(__os, __str.data(), __str.size());
6535	}
6536
6537	/**
6538	* @brief Read a line from stream into a string.
6539	* @param __is Input stream.
6540	* @param __str Buffer to store into.
6541	* @param __delim Character marking end of line.
6542	* @return Reference to the input stream.
6543	*
6544	* Stores characters from @a __is into @a __str until @a __delim is
6545	* found, the end of the stream is encountered, or str.max_size()
6546	* is reached. Any previous contents of @a __str are erased. If
6547	* @a __delim is encountered, it is extracted but not stored into
6548	* @a __str.
6549	*/
6550	template<typename _CharT, typename _Traits, typename _Alloc>
6551	basic_istream<_CharT, _Traits>&
6552	getline(basic_istream<_CharT, _Traits>& __is,
6553	basic_string<_CharT, _Traits, _Alloc>& __str, _CharT __delim);
6554
6555	/**
6556	* @brief Read a line from stream into a string.
6557	* @param __is Input stream.
6558	* @param __str Buffer to store into.
6559	* @return Reference to the input stream.
6560	*
6561	* Stores characters from is into @a __str until '\n' is
6562	* found, the end of the stream is encountered, or str.max_size()
6563	* is reached. Any previous contents of @a __str are erased. If
6564	* end of line is encountered, it is extracted but not stored into
6565	* @a __str.
6566	*/
6567	template<typename _CharT, typename _Traits, typename _Alloc>
6568	inline basic_istream<_CharT, _Traits>&
6569	getline(basic_istream<_CharT, _Traits>& __is,
6570	basic_string<_CharT, _Traits, _Alloc>& __str)
6571	{ return std::getline(__is, __str, __is.widen(`'\n'`)); }
6572
6573	#if __cplusplus >= 201103L
6574	/// Read a line from an rvalue stream into a string.
6575	template<typename _CharT, typename _Traits, typename _Alloc>
6576	inline basic_istream<_CharT, _Traits>&
6577	getline(basic_istream<_CharT, _Traits>&& __is,
6578	basic_string<_CharT, _Traits, _Alloc>& __str, _CharT __delim)
6579	{ return std::getline(__is, __str, __delim); }
6580
6581	/// Read a line from an rvalue stream into a string.
6582	template<typename _CharT, typename _Traits, typename _Alloc>
6583	inline basic_istream<_CharT, _Traits>&
6584	getline(basic_istream<_CharT, _Traits>&& __is,
6585	basic_string<_CharT, _Traits, _Alloc>& __str)
6586	{ return std::getline(__is, __str); }
6587	#endif
6588
6589	template<>
6590	basic_istream<char>&
6591	getline(basic_istream<char>& __in, basic_string<char>& __str,
6592	char __delim);
6593
6594	#ifdef _GLIBCXX_USE_WCHAR_T
6595	template<>
6596	basic_istream<wchar_t>&
6597	getline(basic_istream<wchar_t>& __in, basic_string<wchar_t>& __str,
6598	wchar_t __delim);
6599	#endif
6600
6601	_GLIBCXX_END_NAMESPACE_VERSION
6602	} // namespace
6603
6604	#if __cplusplus >= 201103L
6605
6606	#include <ext/string_conversions.h>
6607	#include <bits/charconv.h>
6608
6609	namespace std _GLIBCXX_VISIBILITY(default)
6610	{
6611	_GLIBCXX_BEGIN_NAMESPACE_VERSION
6612	_GLIBCXX_BEGIN_NAMESPACE_CXX11
6613
6614	#if _GLIBCXX_USE_C99_STDLIB
6615	// 21.4 Numeric Conversions [string.conversions].
6616	inline int
6617	stoi(const string& __str, size_t* __idx = `0`, int __base = `10`)
6618	{ return __gnu_cxx::__stoa<long, int>(&std::strtol, "stoi", __str.c_str(),
6619	__idx, __base); }
6620
6621	inline long
6622	stol(const string& __str, size_t* __idx = `0`, int __base = `10`)
6623	{ return __gnu_cxx::__stoa(&std::strtol, "stol", __str.c_str(),
6624	__idx, __base); }
6625
6626	inline unsigned long
6627	stoul(const string& __str, size_t* __idx = `0`, int __base = `10`)
6628	{ return __gnu_cxx::__stoa(&std::strtoul, "stoul", __str.c_str(),
6629	__idx, __base); }
6630
6631	inline long long
6632	stoll(const string& __str, size_t* __idx = `0`, int __base = `10`)
6633	{ return __gnu_cxx::__stoa(&std::strtoll, "stoll", __str.c_str(),
6634	__idx, __base); }
6635
6636	inline unsigned long long
6637	stoull(const string& __str, size_t* __idx = `0`, int __base = `10`)
6638	{ return __gnu_cxx::__stoa(&std::strtoull, "stoull", __str.c_str(),
6639	__idx, __base); }
6640
6641	// NB: strtof vs strtod.
6642	inline float
6643	stof(const string& __str, size_t* __idx = `0`)
6644	{ return __gnu_cxx::__stoa(&std::strtof, "stof", __str.c_str(), __idx); }
6645
6646	inline double
6647	stod(const string& __str, size_t* __idx = `0`)
6648	{ return __gnu_cxx::__stoa(&std::strtod, "stod", __str.c_str(), __idx); }
6649
6650	inline long double
6651	stold(const string& __str, size_t* __idx = `0`)
6652	{ return __gnu_cxx::__stoa(&std::strtold, "stold", __str.c_str(), __idx); }
6653	#endif // _GLIBCXX_USE_C99_STDLIB
6654
6655	// DR 1261. Insufficent overloads for to_string / to_wstring
6656
6657	inline string
6658	to_string(int __val)
6659	{
6660	const bool __neg = __val < `0`;
6661	const unsigned __uval = __neg ? (unsigned)~__val + `1u` : __val;
6662	const auto __len = __detail::__to_chars_len(__uval);
6663	string __str(__neg + __len, `'-'`);
6664	__detail::__to_chars_10_impl(&__str [__neg], __len, __uval);
6665	return __str;
6666	}
6667
6668	inline string
6669	to_string(unsigned __val)
6670	{
6671	string __str(__detail::__to_chars_len(__val), `'\0'`);
6672	__detail::__to_chars_10_impl(&__str [`0`], __str.size(), __val);
6673	return __str;
6674	}
6675
6676	inline string
6677	to_string(long __val)
6678	{
6679	const bool __neg = __val < `0`;
6680	const unsigned long __uval = __neg ? (unsigned long)~__val + `1ul` : __val;
6681	const auto __len = __detail::__to_chars_len(__uval);
6682	string __str(__neg + __len, `'-'`);
6683	__detail::__to_chars_10_impl(&__str [__neg], __len, __uval);
6684	return __str;
6685	}
6686
6687	inline string
6688	to_string(unsigned long __val)
6689	{
6690	string __str(__detail::__to_chars_len(__val), `'\0'`);
6691	__detail::__to_chars_10_impl(&__str [`0`], __str.size(), __val);
6692	return __str;
6693	}
6694
6695	inline string
6696	to_string(long long __val)
6697	{
6698	const bool __neg = __val < `0`;
6699	const unsigned long long __uval
6700	= __neg ? (unsigned long long)~__val + `1ull` : __val;
6701	const auto __len = __detail::__to_chars_len(__uval);
6702	string __str(__neg + __len, `'-'`);
6703	__detail::__to_chars_10_impl(&__str [__neg], __len, __uval);
6704	return __str;
6705	}
6706
6707	inline string
6708	to_string(unsigned long long __val)
6709	{
6710	string __str(__detail::__to_chars_len(__val), `'\0'`);
6711	__detail::__to_chars_10_impl(&__str [`0`], __str.size(), __val);
6712	return __str;
6713	}
6714
6715	#if _GLIBCXX_USE_C99_STDIO
6716	// NB: (v)snprintf vs sprintf.
6717
6718	inline string
6719	to_string(float __val)
6720	{
6721	const int __n =
6722	__gnu_cxx::__numeric_traits<float>::__max_exponent10 + `20`;
6723	return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
6724	"%f", __val);
6725	}
6726
6727	inline string
6728	to_string(double __val)
6729	{
6730	const int __n =
6731	__gnu_cxx::__numeric_traits<double>::__max_exponent10 + `20`;
6732	return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
6733	"%f", __val);
6734	}
6735
6736	inline string
6737	to_string(long double __val)
6738	{
6739	const int __n =
6740	__gnu_cxx::__numeric_traits<long double>::__max_exponent10 + `20`;
6741	return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
6742	"%Lf", __val);
6743	}
6744	#endif // _GLIBCXX_USE_C99_STDIO
6745
6746	#if defined(_GLIBCXX_USE_WCHAR_T) && _GLIBCXX_USE_C99_WCHAR
6747	inline int
6748	stoi(const wstring& __str, size_t* __idx = `0`, int __base = `10`)
6749	{ return __gnu_cxx::__stoa<long, int>(&std::wcstol, "stoi", __str.c_str(),
6750	__idx, __base); }
6751
6752	inline long
6753	stol(const wstring& __str, size_t* __idx = `0`, int __base = `10`)
6754	{ return __gnu_cxx::__stoa(&std::wcstol, "stol", __str.c_str(),
6755	__idx, __base); }
6756
6757	inline unsigned long
6758	stoul(const wstring& __str, size_t* __idx = `0`, int __base = `10`)
6759	{ return __gnu_cxx::__stoa(&std::wcstoul, "stoul", __str.c_str(),
6760	__idx, __base); }
6761
6762	inline long long
6763	stoll(const wstring& __str, size_t* __idx = `0`, int __base = `10`)
6764	{ return __gnu_cxx::__stoa(&std::wcstoll, "stoll", __str.c_str(),
6765	__idx, __base); }
6766
6767	inline unsigned long long
6768	stoull(const wstring& __str, size_t* __idx = `0`, int __base = `10`)
6769	{ return __gnu_cxx::__stoa(&std::wcstoull, "stoull", __str.c_str(),
6770	__idx, __base); }
6771
6772	// NB: wcstof vs wcstod.
6773	inline float
6774	stof(const wstring& __str, size_t* __idx = `0`)
6775	{ return __gnu_cxx::__stoa(&std::wcstof, "stof", __str.c_str(), __idx); }
6776
6777	inline double
6778	stod(const wstring& __str, size_t* __idx = `0`)
6779	{ return __gnu_cxx::__stoa(&std::wcstod, "stod", __str.c_str(), __idx); }
6780
6781	inline long double
6782	stold(const wstring& __str, size_t* __idx = `0`)
6783	{ return __gnu_cxx::__stoa(&std::wcstold, "stold", __str.c_str(), __idx); }
6784
6785	#ifndef _GLIBCXX_HAVE_BROKEN_VSWPRINTF
6786	// DR 1261.
6787	inline wstring
6788	to_wstring(int __val)
6789	{ return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, `4` * sizeof(int),
6790	L"%d", __val); }
6791
6792	inline wstring
6793	to_wstring(unsigned __val)
6794	{ return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
6795	`4` * sizeof(unsigned),
6796	L"%u", __val); }
6797
6798	inline wstring
6799	to_wstring(long __val)
6800	{ return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, `4` * sizeof(long),
6801	L"%ld", __val); }
6802
6803	inline wstring
6804	to_wstring(unsigned long __val)
6805	{ return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
6806	`4` * sizeof(unsigned long),
6807	L"%lu", __val); }
6808
6809	inline wstring
6810	to_wstring(long long __val)
6811	{ return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
6812	`4` * sizeof(long long),
6813	L"%lld", __val); }
6814
6815	inline wstring
6816	to_wstring(unsigned long long __val)
6817	{ return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
6818	`4` * sizeof(unsigned long long),
6819	L"%llu", __val); }
6820
6821	inline wstring
6822	to_wstring(float __val)
6823	{
6824	const int __n =
6825	__gnu_cxx::__numeric_traits<float>::__max_exponent10 + `20`;
6826	return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
6827	L"%f", __val);
6828	}
6829
6830	inline wstring
6831	to_wstring(double __val)
6832	{
6833	const int __n =
6834	__gnu_cxx::__numeric_traits<double>::__max_exponent10 + `20`;
6835	return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
6836	L"%f", __val);
6837	}
6838
6839	inline wstring
6840	to_wstring(long double __val)
6841	{
6842	const int __n =
6843	__gnu_cxx::__numeric_traits<long double>::__max_exponent10 + `20`;
6844	return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
6845	L"%Lf", __val);
6846	}
6847	#endif // _GLIBCXX_HAVE_BROKEN_VSWPRINTF
6848	#endif // _GLIBCXX_USE_WCHAR_T && _GLIBCXX_USE_C99_WCHAR
6849
6850	_GLIBCXX_END_NAMESPACE_CXX11
6851	_GLIBCXX_END_NAMESPACE_VERSION
6852	} // namespace
6853
6854	#endif /* C++11 */
6855
6856	#if __cplusplus >= 201103L
6857
6858	#include <bits/functional_hash.h>
6859
6860	namespace std _GLIBCXX_VISIBILITY(default)
6861	{
6862	_GLIBCXX_BEGIN_NAMESPACE_VERSION
6863
6864	// DR 1182.
6865
6866	#ifndef _GLIBCXX_COMPATIBILITY_CXX0X
6867	/// std::hash specialization for string.
6868	template<>
6869	struct hash<string>
6870	: public __hash_base<size_t, string>
6871	{
6872	size_t
6873	operator()(const string& __s) const noexcept
6874	{ return std::_Hash_impl::hash(__s.data(), __s.length()); }
6875	};
6876
6877	template<>
6878	struct __is_fast_hash<hash<string>> : std::false_type
6879	{ };
6880
6881	#ifdef _GLIBCXX_USE_WCHAR_T
6882	/// std::hash specialization for wstring.
6883	template<>
6884	struct hash<wstring>
6885	: public __hash_base<size_t, wstring>
6886	{
6887	size_t
6888	operator()(const wstring& __s) const noexcept
6889	{ return std::_Hash_impl::hash(__s.data(),
6890	__s.length() * sizeof(wchar_t)); }
6891	};
6892
6893	template<>
6894	struct __is_fast_hash<hash<wstring>> : std::false_type
6895	{ };
6896	#endif
6897	#endif /* _GLIBCXX_COMPATIBILITY_CXX0X */
6898
6899	#ifdef _GLIBCXX_USE_CHAR8_T
6900	/// std::hash specialization for u8string.
6901	template<>
6902	struct hash<u8string>
6903	: public __hash_base<size_t, u8string>
6904	{
6905	size_t
6906	operator()(const u8string& __s) const noexcept
6907	{ return std::_Hash_impl::hash(__s.data(),
6908	__s.length() * sizeof(char8_t)); }
6909	};
6910
6911	template<>
6912	struct __is_fast_hash<hash<u8string>> : std::false_type
6913	{ };
6914	#endif
6915
6916	/// std::hash specialization for u16string.
6917	template<>
6918	struct hash<u16string>
6919	: public __hash_base<size_t, u16string>
6920	{
6921	size_t
6922	operator()(const u16string& __s) const noexcept
6923	{ return std::_Hash_impl::hash(__s.data(),
6924	__s.length() * sizeof(char16_t)); }
6925	};
6926
6927	template<>
6928	struct __is_fast_hash<hash<u16string>> : std::false_type
6929	{ };
6930
6931	/// std::hash specialization for u32string.
6932	template<>
6933	struct hash<u32string>
6934	: public __hash_base<size_t, u32string>
6935	{
6936	size_t
6937	operator()(const u32string& __s) const noexcept
6938	{ return std::_Hash_impl::hash(__s.data(),
6939	__s.length() * sizeof(char32_t)); }
6940	};
6941
6942	template<>
6943	struct __is_fast_hash<hash<u32string>> : std::false_type
6944	{ };
6945
6946	#if __cplusplus >= 201402L
6947
6948	#define __cpp_lib_string_udls 201304
6949
6950	inline namespace literals
6951	{
6952	inline namespace string_literals
6953	{
6954	#pragma GCC diagnostic push
6955	#pragma GCC diagnostic ignored "-Wliteral-suffix"
6956	_GLIBCXX_DEFAULT_ABI_TAG
6957	inline basic_string<char>
6958	operator""s(const char* __str, size_t __len)
6959	{ return basic_string<char>{__str, __len}; }
6960
6961	#ifdef _GLIBCXX_USE_WCHAR_T
6962	_GLIBCXX_DEFAULT_ABI_TAG
6963	inline basic_string<wchar_t>
6964	operator""s(const wchar_t* __str, size_t __len)
6965	{ return basic_string<wchar_t>{__str, __len}; }
6966	#endif
6967
6968	#ifdef _GLIBCXX_USE_CHAR8_T
6969	_GLIBCXX_DEFAULT_ABI_TAG
6970	inline basic_string<char8_t>
6971	operator""s(const char8_t* __str, size_t __len)
6972	{ return basic_string<char8_t>{__str, __len}; }
6973	#endif
6974
6975	_GLIBCXX_DEFAULT_ABI_TAG
6976	inline basic_string<char16_t>
6977	operator""s(const char16_t* __str, size_t __len)
6978	{ return basic_string<char16_t>{__str, __len}; }
6979
6980	_GLIBCXX_DEFAULT_ABI_TAG
6981	inline basic_string<char32_t>
6982	operator""s(const char32_t* __str, size_t __len)
6983	{ return basic_string<char32_t>{__str, __len}; }
6984
6985	#pragma GCC diagnostic pop
6986	} // inline namespace string_literals
6987	} // inline namespace literals
6988
6989	#if __cplusplus >= 201703L
6990	namespace __detail::__variant
6991	{
6992	template<typename> struct _Never_valueless_alt; // see <variant>
6993
6994	// Provide the strong exception-safety guarantee when emplacing a
6995	// basic_string into a variant, but only if moving the string cannot throw.
6996	template<typename _Tp, typename _Traits, typename _Alloc>
6997	struct _Never_valueless_alt<std::basic_string<_Tp, _Traits, _Alloc>>
6998	: __and_<
6999	is_nothrow_move_constructible<std::basic_string<_Tp, _Traits, _Alloc>>,
7000	is_nothrow_move_assignable<std::basic_string<_Tp, _Traits, _Alloc>>
7001	>::type
7002	{ };
7003	} // namespace __detail::__variant
7004	#endif // C++17
7005	#endif // C++14
7006
7007	_GLIBCXX_END_NAMESPACE_VERSION
7008	} // namespace std
7009
7010	#endif // C++11
7011
7012	#endif /* _BASIC_STRING_H */
7013

Browse the source code of include/c++/11/bits/basic_string.h