1 // Vector implementation -*- C++ -*-
2 
3 // Copyright (C) 2001-2019 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library.  This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /*
26  *
27  * Copyright (c) 1994
28  * Hewlett-Packard Company
29  *
30  * Permission to use, copy, modify, distribute and sell this software
31  * and its documentation for any purpose is hereby granted without fee,
32  * provided that the above copyright notice appear in all copies and
33  * that both that copyright notice and this permission notice appear
34  * in supporting documentation.  Hewlett-Packard Company makes no
35  * representations about the suitability of this software for any
36  * purpose.  It is provided "as is" without express or implied warranty.
37  *
38  *
39  * Copyright (c) 1996
40  * Silicon Graphics Computer Systems, Inc.
41  *
42  * Permission to use, copy, modify, distribute and sell this software
43  * and its documentation for any purpose is hereby granted without fee,
44  * provided that the above copyright notice appear in all copies and
45  * that both that copyright notice and this permission notice appear
46  * in supporting documentation.  Silicon Graphics makes no
47  * representations about the suitability of this  software for any
48  * purpose.  It is provided "as is" without express or implied warranty.
49  */
50 
51 /** @file bits/stl_vector.h
52  *  This is an internal header file, included by other library headers.
53  *  Do not attempt to use it directly. @headername{vector}
54  */
55 
56 #ifndef _STL_VECTOR_H
57 #define _STL_VECTOR_H 1
58 
59 #include <bits/stl_iterator_base_funcs.h>
60 #include <bits/functexcept.h>
61 #include <bits/concept_check.h>
62 #if __cplusplus >= 201103L
63 #include <initializer_list>
64 #endif
65 
66 #include <debug/assertions.h>
67 
68 #if _GLIBCXX_SANITIZE_STD_ALLOCATOR && _GLIBCXX_SANITIZE_VECTOR
69 extern "C" void
70 __sanitizer_annotate_contiguous_container(const void*, const void*,
71 					  const void*, const void*);
72 #endif
73 
_GLIBCXX_VISIBILITY(default)74 namespace std _GLIBCXX_VISIBILITY(default)
75 {
76 _GLIBCXX_BEGIN_NAMESPACE_VERSION
77 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
78 
79   /// See bits/stl_deque.h's _Deque_base for an explanation.
80   template<typename _Tp, typename _Alloc>
81     struct _Vector_base
82     {
83       typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
84 	rebind<_Tp>::other _Tp_alloc_type;
85       typedef typename __gnu_cxx::__alloc_traits<_Tp_alloc_type>::pointer
86        	pointer;
87 
88       struct _Vector_impl_data
89       {
90 	pointer _M_start;
91 	pointer _M_finish;
92 	pointer _M_end_of_storage;
93 
94 	_Vector_impl_data() _GLIBCXX_NOEXCEPT
95 	: _M_start(), _M_finish(), _M_end_of_storage()
96 	{ }
97 
98 #if __cplusplus >= 201103L
99 	_Vector_impl_data(_Vector_impl_data&& __x) noexcept
100 	: _M_start(__x._M_start), _M_finish(__x._M_finish),
101 	  _M_end_of_storage(__x._M_end_of_storage)
102 	{ __x._M_start = __x._M_finish = __x._M_end_of_storage = pointer(); }
103 #endif
104 
105 	void
106 	_M_copy_data(_Vector_impl_data const& __x) _GLIBCXX_NOEXCEPT
107 	{
108 	  _M_start = __x._M_start;
109 	  _M_finish = __x._M_finish;
110 	  _M_end_of_storage = __x._M_end_of_storage;
111 	}
112 
113 	void
114 	_M_swap_data(_Vector_impl_data& __x) _GLIBCXX_NOEXCEPT
115 	{
116 	  // Do not use std::swap(_M_start, __x._M_start), etc as it loses
117 	  // information used by TBAA.
118 	  _Vector_impl_data __tmp;
119 	  __tmp._M_copy_data(*this);
120 	  _M_copy_data(__x);
121 	  __x._M_copy_data(__tmp);
122 	}
123       };
124 
125       struct _Vector_impl
126 	: public _Tp_alloc_type, public _Vector_impl_data
127       {
128 	_Vector_impl() _GLIBCXX_NOEXCEPT_IF(
129 	    is_nothrow_default_constructible<_Tp_alloc_type>::value)
130 	: _Tp_alloc_type()
131 	{ }
132 
133 	_Vector_impl(_Tp_alloc_type const& __a) _GLIBCXX_NOEXCEPT
134 	: _Tp_alloc_type(__a)
135 	{ }
136 
137 #if __cplusplus >= 201103L
138 	// Not defaulted, to enforce noexcept(true) even when
139 	// !is_nothrow_move_constructible<_Tp_alloc_type>.
140 	_Vector_impl(_Vector_impl&& __x) noexcept
141 	: _Tp_alloc_type(std::move(__x)), _Vector_impl_data(std::move(__x))
142 	{ }
143 
144 	_Vector_impl(_Tp_alloc_type&& __a) noexcept
145 	: _Tp_alloc_type(std::move(__a))
146 	{ }
147 
148 	_Vector_impl(_Tp_alloc_type&& __a, _Vector_impl&& __rv) noexcept
149 	: _Tp_alloc_type(std::move(__a)), _Vector_impl_data(std::move(__rv))
150 	{ }
151 #endif
152 
153 #if _GLIBCXX_SANITIZE_STD_ALLOCATOR && _GLIBCXX_SANITIZE_VECTOR
154 	template<typename = _Tp_alloc_type>
155 	  struct _Asan
156 	  {
157 	    typedef typename __gnu_cxx::__alloc_traits<_Tp_alloc_type>
158 	      ::size_type size_type;
159 
160 	    static void _S_shrink(_Vector_impl&, size_type) { }
161 	    static void _S_on_dealloc(_Vector_impl&) { }
162 
163 	    typedef _Vector_impl& _Reinit;
164 
165 	    struct _Grow
166 	    {
167 	      _Grow(_Vector_impl&, size_type) { }
168 	      void _M_grew(size_type) { }
169 	    };
170 	  };
171 
172 	// Enable ASan annotations for memory obtained from std::allocator.
173 	template<typename _Up>
174 	  struct _Asan<allocator<_Up> >
175 	  {
176 	    typedef typename __gnu_cxx::__alloc_traits<_Tp_alloc_type>
177 	      ::size_type size_type;
178 
179 	    // Adjust ASan annotation for [_M_start, _M_end_of_storage) to
180 	    // mark end of valid region as __curr instead of __prev.
181 	    static void
182 	    _S_adjust(_Vector_impl& __impl, pointer __prev, pointer __curr)
183 	    {
184 	      __sanitizer_annotate_contiguous_container(__impl._M_start,
185 		  __impl._M_end_of_storage, __prev, __curr);
186 	    }
187 
188 	    static void
189 	    _S_grow(_Vector_impl& __impl, size_type __n)
190 	    { _S_adjust(__impl, __impl._M_finish, __impl._M_finish + __n); }
191 
192 	    static void
193 	    _S_shrink(_Vector_impl& __impl, size_type __n)
194 	    { _S_adjust(__impl, __impl._M_finish + __n, __impl._M_finish); }
195 
196 	    static void
197 	    _S_on_dealloc(_Vector_impl& __impl)
198 	    {
199 	      if (__impl._M_start)
200 		_S_adjust(__impl, __impl._M_finish, __impl._M_end_of_storage);
201 	    }
202 
203 	    // Used on reallocation to tell ASan unused capacity is invalid.
204 	    struct _Reinit
205 	    {
206 	      explicit _Reinit(_Vector_impl& __impl) : _M_impl(__impl)
207 	      {
208 		// Mark unused capacity as valid again before deallocating it.
209 		_S_on_dealloc(_M_impl);
210 	      }
211 
212 	      ~_Reinit()
213 	      {
214 		// Mark unused capacity as invalid after reallocation.
215 		if (_M_impl._M_start)
216 		  _S_adjust(_M_impl, _M_impl._M_end_of_storage,
217 			    _M_impl._M_finish);
218 	      }
219 
220 	      _Vector_impl& _M_impl;
221 
222 #if __cplusplus >= 201103L
223 	      _Reinit(const _Reinit&) = delete;
224 	      _Reinit& operator=(const _Reinit&) = delete;
225 #endif
226 	    };
227 
228 	    // Tell ASan when unused capacity is initialized to be valid.
229 	    struct _Grow
230 	    {
231 	      _Grow(_Vector_impl& __impl, size_type __n)
232 	      : _M_impl(__impl), _M_n(__n)
233 	      { _S_grow(_M_impl, __n); }
234 
235 	      ~_Grow() { if (_M_n) _S_shrink(_M_impl, _M_n); }
236 
237 	      void _M_grew(size_type __n) { _M_n -= __n; }
238 
239 #if __cplusplus >= 201103L
240 	      _Grow(const _Grow&) = delete;
241 	      _Grow& operator=(const _Grow&) = delete;
242 #endif
243 	    private:
244 	      _Vector_impl& _M_impl;
245 	      size_type _M_n;
246 	    };
247 	  };
248 
249 #define _GLIBCXX_ASAN_ANNOTATE_REINIT \
250   typename _Base::_Vector_impl::template _Asan<>::_Reinit const \
251 	__attribute__((__unused__)) __reinit_guard(this->_M_impl)
252 #define _GLIBCXX_ASAN_ANNOTATE_GROW(n) \
253   typename _Base::_Vector_impl::template _Asan<>::_Grow \
254 	__attribute__((__unused__)) __grow_guard(this->_M_impl, (n))
255 #define _GLIBCXX_ASAN_ANNOTATE_GREW(n) __grow_guard._M_grew(n)
256 #define _GLIBCXX_ASAN_ANNOTATE_SHRINK(n) \
257   _Base::_Vector_impl::template _Asan<>::_S_shrink(this->_M_impl, n)
258 #define _GLIBCXX_ASAN_ANNOTATE_BEFORE_DEALLOC \
259   _Base::_Vector_impl::template _Asan<>::_S_on_dealloc(this->_M_impl)
260 #else // ! (_GLIBCXX_SANITIZE_STD_ALLOCATOR && _GLIBCXX_SANITIZE_VECTOR)
261 #define _GLIBCXX_ASAN_ANNOTATE_REINIT
262 #define _GLIBCXX_ASAN_ANNOTATE_GROW(n)
263 #define _GLIBCXX_ASAN_ANNOTATE_GREW(n)
264 #define _GLIBCXX_ASAN_ANNOTATE_SHRINK(n)
265 #define _GLIBCXX_ASAN_ANNOTATE_BEFORE_DEALLOC
266 #endif // _GLIBCXX_SANITIZE_STD_ALLOCATOR && _GLIBCXX_SANITIZE_VECTOR
267       };
268 
269     public:
270       typedef _Alloc allocator_type;
271 
272       _Tp_alloc_type&
273       _M_get_Tp_allocator() _GLIBCXX_NOEXCEPT
274       { return this->_M_impl; }
275 
276       const _Tp_alloc_type&
277       _M_get_Tp_allocator() const _GLIBCXX_NOEXCEPT
278       { return this->_M_impl; }
279 
280       allocator_type
281       get_allocator() const _GLIBCXX_NOEXCEPT
282       { return allocator_type(_M_get_Tp_allocator()); }
283 
284 #if __cplusplus >= 201103L
285       _Vector_base() = default;
286 #else
287       _Vector_base() { }
288 #endif
289 
290       _Vector_base(const allocator_type& __a) _GLIBCXX_NOEXCEPT
291       : _M_impl(__a) { }
292 
293       // Kept for ABI compatibility.
294 #if !_GLIBCXX_INLINE_VERSION
295       _Vector_base(size_t __n)
296       : _M_impl()
297       { _M_create_storage(__n); }
298 #endif
299 
300       _Vector_base(size_t __n, const allocator_type& __a)
301       : _M_impl(__a)
302       { _M_create_storage(__n); }
303 
304 #if __cplusplus >= 201103L
305       _Vector_base(_Vector_base&&) = default;
306 
307       // Kept for ABI compatibility.
308 # if !_GLIBCXX_INLINE_VERSION
309       _Vector_base(_Tp_alloc_type&& __a) noexcept
310       : _M_impl(std::move(__a)) { }
311 
312       _Vector_base(_Vector_base&& __x, const allocator_type& __a)
313       : _M_impl(__a)
314       {
315 	if (__x.get_allocator() == __a)
316 	  this->_M_impl._M_swap_data(__x._M_impl);
317 	else
318 	  {
319 	    size_t __n = __x._M_impl._M_finish - __x._M_impl._M_start;
320 	    _M_create_storage(__n);
321 	  }
322       }
323 # endif
324 
325       _Vector_base(const allocator_type& __a, _Vector_base&& __x)
326       : _M_impl(_Tp_alloc_type(__a), std::move(__x._M_impl))
327       { }
328 #endif
329 
330       ~_Vector_base() _GLIBCXX_NOEXCEPT
331       {
332 	_M_deallocate(_M_impl._M_start,
333 		      _M_impl._M_end_of_storage - _M_impl._M_start);
334       }
335 
336     public:
337       _Vector_impl _M_impl;
338 
339       pointer
340       _M_allocate(size_t __n)
341       {
342 	typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type> _Tr;
343 	return __n != 0 ? _Tr::allocate(_M_impl, __n) : pointer();
344       }
345 
346       void
347       _M_deallocate(pointer __p, size_t __n)
348       {
349 	typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type> _Tr;
350 	if (__p)
351 	  _Tr::deallocate(_M_impl, __p, __n);
352       }
353 
354     protected:
355       void
356       _M_create_storage(size_t __n)
357       {
358 	this->_M_impl._M_start = this->_M_allocate(__n);
359 	this->_M_impl._M_finish = this->_M_impl._M_start;
360 	this->_M_impl._M_end_of_storage = this->_M_impl._M_start + __n;
361       }
362     };
363 
364   /**
365    *  @brief A standard container which offers fixed time access to
366    *  individual elements in any order.
367    *
368    *  @ingroup sequences
369    *
370    *  @tparam _Tp  Type of element.
371    *  @tparam _Alloc  Allocator type, defaults to allocator<_Tp>.
372    *
373    *  Meets the requirements of a <a href="tables.html#65">container</a>, a
374    *  <a href="tables.html#66">reversible container</a>, and a
375    *  <a href="tables.html#67">sequence</a>, including the
376    *  <a href="tables.html#68">optional sequence requirements</a> with the
377    *  %exception of @c push_front and @c pop_front.
378    *
379    *  In some terminology a %vector can be described as a dynamic
380    *  C-style array, it offers fast and efficient access to individual
381    *  elements in any order and saves the user from worrying about
382    *  memory and size allocation.  Subscripting ( @c [] ) access is
383    *  also provided as with C-style arrays.
384   */
385   template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
386     class vector : protected _Vector_base<_Tp, _Alloc>
387     {
388 #ifdef _GLIBCXX_CONCEPT_CHECKS
389       // Concept requirements.
390       typedef typename _Alloc::value_type		_Alloc_value_type;
391 # if __cplusplus < 201103L
392       __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
393 # endif
394       __glibcxx_class_requires2(_Tp, _Alloc_value_type, _SameTypeConcept)
395 #endif
396 
397 #if __cplusplus >= 201103L
398       static_assert(is_same<typename remove_cv<_Tp>::type, _Tp>::value,
399 	  "std::vector must have a non-const, non-volatile value_type");
400 # ifdef __STRICT_ANSI__
401       static_assert(is_same<typename _Alloc::value_type, _Tp>::value,
402 	  "std::vector must have the same value_type as its allocator");
403 # endif
404 #endif
405 
406       typedef _Vector_base<_Tp, _Alloc>			_Base;
407       typedef typename _Base::_Tp_alloc_type		_Tp_alloc_type;
408       typedef __gnu_cxx::__alloc_traits<_Tp_alloc_type>	_Alloc_traits;
409 
410     public:
411       typedef _Tp					value_type;
412       typedef typename _Base::pointer			pointer;
413       typedef typename _Alloc_traits::const_pointer	const_pointer;
414       typedef typename _Alloc_traits::reference		reference;
415       typedef typename _Alloc_traits::const_reference	const_reference;
416       typedef __gnu_cxx::__normal_iterator<pointer, vector> iterator;
417       typedef __gnu_cxx::__normal_iterator<const_pointer, vector>
418       const_iterator;
419       typedef std::reverse_iterator<const_iterator>	const_reverse_iterator;
420       typedef std::reverse_iterator<iterator>		reverse_iterator;
421       typedef size_t					size_type;
422       typedef ptrdiff_t					difference_type;
423       typedef _Alloc					allocator_type;
424 
425     private:
426 #if __cplusplus >= 201103L
427       static constexpr bool
428       _S_nothrow_relocate(true_type)
429       {
430 	return noexcept(std::__relocate_a(std::declval<pointer>(),
431 					  std::declval<pointer>(),
432 					  std::declval<pointer>(),
433 					  std::declval<_Tp_alloc_type&>()));
434       }
435 
436       static constexpr bool
437       _S_nothrow_relocate(false_type)
438       { return false; }
439 
440       static constexpr bool
441       _S_use_relocate()
442       {
443 	// Instantiating std::__relocate_a might cause an error outside the
444 	// immediate context (in __relocate_object_a's noexcept-specifier),
445 	// so only do it if we know the type can be move-inserted into *this.
446 	return _S_nothrow_relocate(__is_move_insertable<_Tp_alloc_type>{});
447       }
448 
449       static pointer
450       _S_do_relocate(pointer __first, pointer __last, pointer __result,
451 		     _Tp_alloc_type& __alloc, true_type) noexcept
452       {
453 	return std::__relocate_a(__first, __last, __result, __alloc);
454       }
455 
456       static pointer
457       _S_do_relocate(pointer, pointer, pointer __result,
458 		     _Tp_alloc_type&, false_type) noexcept
459       { return __result; }
460 
461       static pointer
462       _S_relocate(pointer __first, pointer __last, pointer __result,
463 		  _Tp_alloc_type& __alloc) noexcept
464       {
465 	using __do_it = __bool_constant<_S_use_relocate()>;
466 	return _S_do_relocate(__first, __last, __result, __alloc, __do_it{});
467       }
468 #endif // C++11
469 
470     protected:
471       using _Base::_M_allocate;
472       using _Base::_M_deallocate;
473       using _Base::_M_impl;
474       using _Base::_M_get_Tp_allocator;
475 
476     public:
477       // [23.2.4.1] construct/copy/destroy
478       // (assign() and get_allocator() are also listed in this section)
479 
480       /**
481        *  @brief  Creates a %vector with no elements.
482        */
483 #if __cplusplus >= 201103L
484       vector() = default;
485 #else
486       vector() { }
487 #endif
488 
489       /**
490        *  @brief  Creates a %vector with no elements.
491        *  @param  __a  An allocator object.
492        */
493       explicit
494       vector(const allocator_type& __a) _GLIBCXX_NOEXCEPT
495       : _Base(__a) { }
496 
497 #if __cplusplus >= 201103L
498       /**
499        *  @brief  Creates a %vector with default constructed elements.
500        *  @param  __n  The number of elements to initially create.
501        *  @param  __a  An allocator.
502        *
503        *  This constructor fills the %vector with @a __n default
504        *  constructed elements.
505        */
506       explicit
507       vector(size_type __n, const allocator_type& __a = allocator_type())
508       : _Base(_S_check_init_len(__n, __a), __a)
509       { _M_default_initialize(__n); }
510 
511       /**
512        *  @brief  Creates a %vector with copies of an exemplar element.
513        *  @param  __n  The number of elements to initially create.
514        *  @param  __value  An element to copy.
515        *  @param  __a  An allocator.
516        *
517        *  This constructor fills the %vector with @a __n copies of @a __value.
518        */
519       vector(size_type __n, const value_type& __value,
520 	     const allocator_type& __a = allocator_type())
521       : _Base(_S_check_init_len(__n, __a), __a)
522       { _M_fill_initialize(__n, __value); }
523 #else
524       /**
525        *  @brief  Creates a %vector with copies of an exemplar element.
526        *  @param  __n  The number of elements to initially create.
527        *  @param  __value  An element to copy.
528        *  @param  __a  An allocator.
529        *
530        *  This constructor fills the %vector with @a __n copies of @a __value.
531        */
532       explicit
533       vector(size_type __n, const value_type& __value = value_type(),
534 	     const allocator_type& __a = allocator_type())
535       : _Base(_S_check_init_len(__n, __a), __a)
536       { _M_fill_initialize(__n, __value); }
537 #endif
538 
539       /**
540        *  @brief  %Vector copy constructor.
541        *  @param  __x  A %vector of identical element and allocator types.
542        *
543        *  All the elements of @a __x are copied, but any unused capacity in
544        *  @a __x  will not be copied
545        *  (i.e. capacity() == size() in the new %vector).
546        *
547        *  The newly-created %vector uses a copy of the allocator object used
548        *  by @a __x (unless the allocator traits dictate a different object).
549        */
550       vector(const vector& __x)
551       : _Base(__x.size(),
552 	_Alloc_traits::_S_select_on_copy(__x._M_get_Tp_allocator()))
553       {
554 	this->_M_impl._M_finish =
555 	  std::__uninitialized_copy_a(__x.begin(), __x.end(),
556 				      this->_M_impl._M_start,
557 				      _M_get_Tp_allocator());
558       }
559 
560 #if __cplusplus >= 201103L
561       /**
562        *  @brief  %Vector move constructor.
563        *
564        *  The newly-created %vector contains the exact contents of the
565        *  moved instance.
566        *  The contents of the moved instance are a valid, but unspecified
567        *  %vector.
568        */
569       vector(vector&&) noexcept = default;
570 
571       /// Copy constructor with alternative allocator
572       vector(const vector& __x, const allocator_type& __a)
573       : _Base(__x.size(), __a)
574       {
575 	this->_M_impl._M_finish =
576 	  std::__uninitialized_copy_a(__x.begin(), __x.end(),
577 				      this->_M_impl._M_start,
578 				      _M_get_Tp_allocator());
579       }
580 
581     private:
582       vector(vector&& __rv, const allocator_type& __m, true_type) noexcept
583       : _Base(__m, std::move(__rv))
584       { }
585 
586       vector(vector&& __rv, const allocator_type& __m, false_type)
587       : _Base(__m)
588       {
589 	if (__rv.get_allocator() == __m)
590 	  this->_M_impl._M_swap_data(__rv._M_impl);
591 	else if (!__rv.empty())
592 	  {
593 	    this->_M_create_storage(__rv.size());
594 	    this->_M_impl._M_finish =
595 	      std::__uninitialized_move_a(__rv.begin(), __rv.end(),
596 					  this->_M_impl._M_start,
597 					  _M_get_Tp_allocator());
598 	    __rv.clear();
599 	  }
600       }
601 
602     public:
603       /// Move constructor with alternative allocator
604       vector(vector&& __rv, const allocator_type& __m)
605       noexcept( noexcept(
606 	vector(std::declval<vector&&>(), std::declval<const allocator_type&>(),
607 	       std::declval<typename _Alloc_traits::is_always_equal>())) )
608       : vector(std::move(__rv), __m, typename _Alloc_traits::is_always_equal{})
609       { }
610 
611       /**
612        *  @brief  Builds a %vector from an initializer list.
613        *  @param  __l  An initializer_list.
614        *  @param  __a  An allocator.
615        *
616        *  Create a %vector consisting of copies of the elements in the
617        *  initializer_list @a __l.
618        *
619        *  This will call the element type's copy constructor N times
620        *  (where N is @a __l.size()) and do no memory reallocation.
621        */
622       vector(initializer_list<value_type> __l,
623 	     const allocator_type& __a = allocator_type())
624       : _Base(__a)
625       {
626 	_M_range_initialize(__l.begin(), __l.end(),
627 			    random_access_iterator_tag());
628       }
629 #endif
630 
631       /**
632        *  @brief  Builds a %vector from a range.
633        *  @param  __first  An input iterator.
634        *  @param  __last  An input iterator.
635        *  @param  __a  An allocator.
636        *
637        *  Create a %vector consisting of copies of the elements from
638        *  [first,last).
639        *
640        *  If the iterators are forward, bidirectional, or
641        *  random-access, then this will call the elements' copy
642        *  constructor N times (where N is distance(first,last)) and do
643        *  no memory reallocation.  But if only input iterators are
644        *  used, then this will do at most 2N calls to the copy
645        *  constructor, and logN memory reallocations.
646        */
647 #if __cplusplus >= 201103L
648       template<typename _InputIterator,
649 	       typename = std::_RequireInputIter<_InputIterator>>
650 	vector(_InputIterator __first, _InputIterator __last,
651 	       const allocator_type& __a = allocator_type())
652 	: _Base(__a)
653 	{
654 	  _M_range_initialize(__first, __last,
655 			      std::__iterator_category(__first));
656 	}
657 #else
658       template<typename _InputIterator>
659 	vector(_InputIterator __first, _InputIterator __last,
660 	       const allocator_type& __a = allocator_type())
661 	: _Base(__a)
662 	{
663 	  // Check whether it's an integral type.  If so, it's not an iterator.
664 	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
665 	  _M_initialize_dispatch(__first, __last, _Integral());
666 	}
667 #endif
668 
669       /**
670        *  The dtor only erases the elements, and note that if the
671        *  elements themselves are pointers, the pointed-to memory is
672        *  not touched in any way.  Managing the pointer is the user's
673        *  responsibility.
674        */
675       ~vector() _GLIBCXX_NOEXCEPT
676       {
677 	std::_Destroy(this->_M_impl._M_start, this->_M_impl._M_finish,
678 		      _M_get_Tp_allocator());
679 	_GLIBCXX_ASAN_ANNOTATE_BEFORE_DEALLOC;
680       }
681 
682       /**
683        *  @brief  %Vector assignment operator.
684        *  @param  __x  A %vector of identical element and allocator types.
685        *
686        *  All the elements of @a __x are copied, but any unused capacity in
687        *  @a __x will not be copied.
688        *
689        *  Whether the allocator is copied depends on the allocator traits.
690        */
691       vector&
692       operator=(const vector& __x);
693 
694 #if __cplusplus >= 201103L
695       /**
696        *  @brief  %Vector move assignment operator.
697        *  @param  __x  A %vector of identical element and allocator types.
698        *
699        *  The contents of @a __x are moved into this %vector (without copying,
700        *  if the allocators permit it).
701        *  Afterwards @a __x is a valid, but unspecified %vector.
702        *
703        *  Whether the allocator is moved depends on the allocator traits.
704        */
705       vector&
706       operator=(vector&& __x) noexcept(_Alloc_traits::_S_nothrow_move())
707       {
708 	constexpr bool __move_storage =
709 	  _Alloc_traits::_S_propagate_on_move_assign()
710 	  || _Alloc_traits::_S_always_equal();
711 	_M_move_assign(std::move(__x), __bool_constant<__move_storage>());
712 	return *this;
713       }
714 
715       /**
716        *  @brief  %Vector list assignment operator.
717        *  @param  __l  An initializer_list.
718        *
719        *  This function fills a %vector with copies of the elements in the
720        *  initializer list @a __l.
721        *
722        *  Note that the assignment completely changes the %vector and
723        *  that the resulting %vector's size is the same as the number
724        *  of elements assigned.
725        */
726       vector&
727       operator=(initializer_list<value_type> __l)
728       {
729 	this->_M_assign_aux(__l.begin(), __l.end(),
730 			    random_access_iterator_tag());
731 	return *this;
732       }
733 #endif
734 
735       /**
736        *  @brief  Assigns a given value to a %vector.
737        *  @param  __n  Number of elements to be assigned.
738        *  @param  __val  Value to be assigned.
739        *
740        *  This function fills a %vector with @a __n copies of the given
741        *  value.  Note that the assignment completely changes the
742        *  %vector and that the resulting %vector's size is the same as
743        *  the number of elements assigned.
744        */
745       void
746       assign(size_type __n, const value_type& __val)
747       { _M_fill_assign(__n, __val); }
748 
749       /**
750        *  @brief  Assigns a range to a %vector.
751        *  @param  __first  An input iterator.
752        *  @param  __last   An input iterator.
753        *
754        *  This function fills a %vector with copies of the elements in the
755        *  range [__first,__last).
756        *
757        *  Note that the assignment completely changes the %vector and
758        *  that the resulting %vector's size is the same as the number
759        *  of elements assigned.
760        */
761 #if __cplusplus >= 201103L
762       template<typename _InputIterator,
763 	       typename = std::_RequireInputIter<_InputIterator>>
764 	void
765 	assign(_InputIterator __first, _InputIterator __last)
766 	{ _M_assign_dispatch(__first, __last, __false_type()); }
767 #else
768       template<typename _InputIterator>
769 	void
770 	assign(_InputIterator __first, _InputIterator __last)
771 	{
772 	  // Check whether it's an integral type.  If so, it's not an iterator.
773 	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
774 	  _M_assign_dispatch(__first, __last, _Integral());
775 	}
776 #endif
777 
778 #if __cplusplus >= 201103L
779       /**
780        *  @brief  Assigns an initializer list to a %vector.
781        *  @param  __l  An initializer_list.
782        *
783        *  This function fills a %vector with copies of the elements in the
784        *  initializer list @a __l.
785        *
786        *  Note that the assignment completely changes the %vector and
787        *  that the resulting %vector's size is the same as the number
788        *  of elements assigned.
789        */
790       void
791       assign(initializer_list<value_type> __l)
792       {
793 	this->_M_assign_aux(__l.begin(), __l.end(),
794 			    random_access_iterator_tag());
795       }
796 #endif
797 
798       /// Get a copy of the memory allocation object.
799       using _Base::get_allocator;
800 
801       // iterators
802       /**
803        *  Returns a read/write iterator that points to the first
804        *  element in the %vector.  Iteration is done in ordinary
805        *  element order.
806        */
807       iterator
808       begin() _GLIBCXX_NOEXCEPT
809       { return iterator(this->_M_impl._M_start); }
810 
811       /**
812        *  Returns a read-only (constant) iterator that points to the
813        *  first element in the %vector.  Iteration is done in ordinary
814        *  element order.
815        */
816       const_iterator
817       begin() const _GLIBCXX_NOEXCEPT
818       { return const_iterator(this->_M_impl._M_start); }
819 
820       /**
821        *  Returns a read/write iterator that points one past the last
822        *  element in the %vector.  Iteration is done in ordinary
823        *  element order.
824        */
825       iterator
826       end() _GLIBCXX_NOEXCEPT
827       { return iterator(this->_M_impl._M_finish); }
828 
829       /**
830        *  Returns a read-only (constant) iterator that points one past
831        *  the last element in the %vector.  Iteration is done in
832        *  ordinary element order.
833        */
834       const_iterator
835       end() const _GLIBCXX_NOEXCEPT
836       { return const_iterator(this->_M_impl._M_finish); }
837 
838       /**
839        *  Returns a read/write reverse iterator that points to the
840        *  last element in the %vector.  Iteration is done in reverse
841        *  element order.
842        */
843       reverse_iterator
844       rbegin() _GLIBCXX_NOEXCEPT
845       { return reverse_iterator(end()); }
846 
847       /**
848        *  Returns a read-only (constant) reverse iterator that points
849        *  to the last element in the %vector.  Iteration is done in
850        *  reverse element order.
851        */
852       const_reverse_iterator
853       rbegin() const _GLIBCXX_NOEXCEPT
854       { return const_reverse_iterator(end()); }
855 
856       /**
857        *  Returns a read/write reverse iterator that points to one
858        *  before the first element in the %vector.  Iteration is done
859        *  in reverse element order.
860        */
861       reverse_iterator
862       rend() _GLIBCXX_NOEXCEPT
863       { return reverse_iterator(begin()); }
864 
865       /**
866        *  Returns a read-only (constant) reverse iterator that points
867        *  to one before the first element in the %vector.  Iteration
868        *  is done in reverse element order.
869        */
870       const_reverse_iterator
871       rend() const _GLIBCXX_NOEXCEPT
872       { return const_reverse_iterator(begin()); }
873 
874 #if __cplusplus >= 201103L
875       /**
876        *  Returns a read-only (constant) iterator that points to the
877        *  first element in the %vector.  Iteration is done in ordinary
878        *  element order.
879        */
880       const_iterator
881       cbegin() const noexcept
882       { return const_iterator(this->_M_impl._M_start); }
883 
884       /**
885        *  Returns a read-only (constant) iterator that points one past
886        *  the last element in the %vector.  Iteration is done in
887        *  ordinary element order.
888        */
889       const_iterator
890       cend() const noexcept
891       { return const_iterator(this->_M_impl._M_finish); }
892 
893       /**
894        *  Returns a read-only (constant) reverse iterator that points
895        *  to the last element in the %vector.  Iteration is done in
896        *  reverse element order.
897        */
898       const_reverse_iterator
899       crbegin() const noexcept
900       { return const_reverse_iterator(end()); }
901 
902       /**
903        *  Returns a read-only (constant) reverse iterator that points
904        *  to one before the first element in the %vector.  Iteration
905        *  is done in reverse element order.
906        */
907       const_reverse_iterator
908       crend() const noexcept
909       { return const_reverse_iterator(begin()); }
910 #endif
911 
912       // [23.2.4.2] capacity
913       /**  Returns the number of elements in the %vector.  */
914       size_type
915       size() const _GLIBCXX_NOEXCEPT
916       { return size_type(this->_M_impl._M_finish - this->_M_impl._M_start); }
917 
918       /**  Returns the size() of the largest possible %vector.  */
919       size_type
920       max_size() const _GLIBCXX_NOEXCEPT
921       { return _S_max_size(_M_get_Tp_allocator()); }
922 
923 #if __cplusplus >= 201103L
924       /**
925        *  @brief  Resizes the %vector to the specified number of elements.
926        *  @param  __new_size  Number of elements the %vector should contain.
927        *
928        *  This function will %resize the %vector to the specified
929        *  number of elements.  If the number is smaller than the
930        *  %vector's current size the %vector is truncated, otherwise
931        *  default constructed elements are appended.
932        */
933       void
934       resize(size_type __new_size)
935       {
936 	if (__new_size > size())
937 	  _M_default_append(__new_size - size());
938 	else if (__new_size < size())
939 	  _M_erase_at_end(this->_M_impl._M_start + __new_size);
940       }
941 
942       /**
943        *  @brief  Resizes the %vector to the specified number of elements.
944        *  @param  __new_size  Number of elements the %vector should contain.
945        *  @param  __x  Data with which new elements should be populated.
946        *
947        *  This function will %resize the %vector to the specified
948        *  number of elements.  If the number is smaller than the
949        *  %vector's current size the %vector is truncated, otherwise
950        *  the %vector is extended and new elements are populated with
951        *  given data.
952        */
953       void
954       resize(size_type __new_size, const value_type& __x)
955       {
956 	if (__new_size > size())
957 	  _M_fill_insert(end(), __new_size - size(), __x);
958 	else if (__new_size < size())
959 	  _M_erase_at_end(this->_M_impl._M_start + __new_size);
960       }
961 #else
962       /**
963        *  @brief  Resizes the %vector to the specified number of elements.
964        *  @param  __new_size  Number of elements the %vector should contain.
965        *  @param  __x  Data with which new elements should be populated.
966        *
967        *  This function will %resize the %vector to the specified
968        *  number of elements.  If the number is smaller than the
969        *  %vector's current size the %vector is truncated, otherwise
970        *  the %vector is extended and new elements are populated with
971        *  given data.
972        */
973       void
974       resize(size_type __new_size, value_type __x = value_type())
975       {
976 	if (__new_size > size())
977 	  _M_fill_insert(end(), __new_size - size(), __x);
978 	else if (__new_size < size())
979 	  _M_erase_at_end(this->_M_impl._M_start + __new_size);
980       }
981 #endif
982 
983 #if __cplusplus >= 201103L
984       /**  A non-binding request to reduce capacity() to size().  */
985       void
986       shrink_to_fit()
987       { _M_shrink_to_fit(); }
988 #endif
989 
990       /**
991        *  Returns the total number of elements that the %vector can
992        *  hold before needing to allocate more memory.
993        */
994       size_type
995       capacity() const _GLIBCXX_NOEXCEPT
996       { return size_type(this->_M_impl._M_end_of_storage
997 			 - this->_M_impl._M_start); }
998 
999       /**
1000        *  Returns true if the %vector is empty.  (Thus begin() would
1001        *  equal end().)
1002        */
1003       _GLIBCXX_NODISCARD bool
1004       empty() const _GLIBCXX_NOEXCEPT
1005       { return begin() == end(); }
1006 
1007       /**
1008        *  @brief  Attempt to preallocate enough memory for specified number of
1009        *          elements.
1010        *  @param  __n  Number of elements required.
1011        *  @throw  std::length_error  If @a n exceeds @c max_size().
1012        *
1013        *  This function attempts to reserve enough memory for the
1014        *  %vector to hold the specified number of elements.  If the
1015        *  number requested is more than max_size(), length_error is
1016        *  thrown.
1017        *
1018        *  The advantage of this function is that if optimal code is a
1019        *  necessity and the user can determine the number of elements
1020        *  that will be required, the user can reserve the memory in
1021        *  %advance, and thus prevent a possible reallocation of memory
1022        *  and copying of %vector data.
1023        */
1024       void
1025       reserve(size_type __n);
1026 
1027       // element access
1028       /**
1029        *  @brief  Subscript access to the data contained in the %vector.
1030        *  @param __n The index of the element for which data should be
1031        *  accessed.
1032        *  @return  Read/write reference to data.
1033        *
1034        *  This operator allows for easy, array-style, data access.
1035        *  Note that data access with this operator is unchecked and
1036        *  out_of_range lookups are not defined. (For checked lookups
1037        *  see at().)
1038        */
1039       reference
1040       operator[](size_type __n) _GLIBCXX_NOEXCEPT
1041       {
1042 	__glibcxx_requires_subscript(__n);
1043 	return *(this->_M_impl._M_start + __n);
1044       }
1045 
1046       /**
1047        *  @brief  Subscript access to the data contained in the %vector.
1048        *  @param __n The index of the element for which data should be
1049        *  accessed.
1050        *  @return  Read-only (constant) reference to data.
1051        *
1052        *  This operator allows for easy, array-style, data access.
1053        *  Note that data access with this operator is unchecked and
1054        *  out_of_range lookups are not defined. (For checked lookups
1055        *  see at().)
1056        */
1057       const_reference
1058       operator[](size_type __n) const _GLIBCXX_NOEXCEPT
1059       {
1060 	__glibcxx_requires_subscript(__n);
1061 	return *(this->_M_impl._M_start + __n);
1062       }
1063 
1064     protected:
1065       /// Safety check used only from at().
1066       void
1067       _M_range_check(size_type __n) const
1068       {
1069 	if (__n >= this->size())
1070 	  __throw_out_of_range_fmt(__N("vector::_M_range_check: __n "
1071 				       "(which is %zu) >= this->size() "
1072 				       "(which is %zu)"),
1073 				   __n, this->size());
1074       }
1075 
1076     public:
1077       /**
1078        *  @brief  Provides access to the data contained in the %vector.
1079        *  @param __n The index of the element for which data should be
1080        *  accessed.
1081        *  @return  Read/write reference to data.
1082        *  @throw  std::out_of_range  If @a __n is an invalid index.
1083        *
1084        *  This function provides for safer data access.  The parameter
1085        *  is first checked that it is in the range of the vector.  The
1086        *  function throws out_of_range if the check fails.
1087        */
1088       reference
1089       at(size_type __n)
1090       {
1091 	_M_range_check(__n);
1092 	return (*this)[__n];
1093       }
1094 
1095       /**
1096        *  @brief  Provides access to the data contained in the %vector.
1097        *  @param __n The index of the element for which data should be
1098        *  accessed.
1099        *  @return  Read-only (constant) reference to data.
1100        *  @throw  std::out_of_range  If @a __n is an invalid index.
1101        *
1102        *  This function provides for safer data access.  The parameter
1103        *  is first checked that it is in the range of the vector.  The
1104        *  function throws out_of_range if the check fails.
1105        */
1106       const_reference
1107       at(size_type __n) const
1108       {
1109 	_M_range_check(__n);
1110 	return (*this)[__n];
1111       }
1112 
1113       /**
1114        *  Returns a read/write reference to the data at the first
1115        *  element of the %vector.
1116        */
1117       reference
1118       front() _GLIBCXX_NOEXCEPT
1119       {
1120 	__glibcxx_requires_nonempty();
1121 	return *begin();
1122       }
1123 
1124       /**
1125        *  Returns a read-only (constant) reference to the data at the first
1126        *  element of the %vector.
1127        */
1128       const_reference
1129       front() const _GLIBCXX_NOEXCEPT
1130       {
1131 	__glibcxx_requires_nonempty();
1132 	return *begin();
1133       }
1134 
1135       /**
1136        *  Returns a read/write reference to the data at the last
1137        *  element of the %vector.
1138        */
1139       reference
1140       back() _GLIBCXX_NOEXCEPT
1141       {
1142 	__glibcxx_requires_nonempty();
1143 	return *(end() - 1);
1144       }
1145 
1146       /**
1147        *  Returns a read-only (constant) reference to the data at the
1148        *  last element of the %vector.
1149        */
1150       const_reference
1151       back() const _GLIBCXX_NOEXCEPT
1152       {
1153 	__glibcxx_requires_nonempty();
1154 	return *(end() - 1);
1155       }
1156 
1157       // _GLIBCXX_RESOLVE_LIB_DEFECTS
1158       // DR 464. Suggestion for new member functions in standard containers.
1159       // data access
1160       /**
1161        *   Returns a pointer such that [data(), data() + size()) is a valid
1162        *   range.  For a non-empty %vector, data() == &front().
1163        */
1164       _Tp*
1165       data() _GLIBCXX_NOEXCEPT
1166       { return _M_data_ptr(this->_M_impl._M_start); }
1167 
1168       const _Tp*
1169       data() const _GLIBCXX_NOEXCEPT
1170       { return _M_data_ptr(this->_M_impl._M_start); }
1171 
1172       // [23.2.4.3] modifiers
1173       /**
1174        *  @brief  Add data to the end of the %vector.
1175        *  @param  __x  Data to be added.
1176        *
1177        *  This is a typical stack operation.  The function creates an
1178        *  element at the end of the %vector and assigns the given data
1179        *  to it.  Due to the nature of a %vector this operation can be
1180        *  done in constant time if the %vector has preallocated space
1181        *  available.
1182        */
1183       void
1184       push_back(const value_type& __x)
1185       {
1186 	if (this->_M_impl._M_finish != this->_M_impl._M_end_of_storage)
1187 	  {
1188 	    _GLIBCXX_ASAN_ANNOTATE_GROW(1);
1189 	    _Alloc_traits::construct(this->_M_impl, this->_M_impl._M_finish,
1190 				     __x);
1191 	    ++this->_M_impl._M_finish;
1192 	    _GLIBCXX_ASAN_ANNOTATE_GREW(1);
1193 	  }
1194 	else
1195 	  _M_realloc_insert(end(), __x);
1196       }
1197 
1198 #if __cplusplus >= 201103L
1199       void
1200       push_back(value_type&& __x)
1201       { emplace_back(std::move(__x)); }
1202 
1203       template<typename... _Args>
1204 #if __cplusplus > 201402L
1205 	reference
1206 #else
1207 	void
1208 #endif
1209 	emplace_back(_Args&&... __args);
1210 #endif
1211 
1212       /**
1213        *  @brief  Removes last element.
1214        *
1215        *  This is a typical stack operation. It shrinks the %vector by one.
1216        *
1217        *  Note that no data is returned, and if the last element's
1218        *  data is needed, it should be retrieved before pop_back() is
1219        *  called.
1220        */
1221       void
1222       pop_back() _GLIBCXX_NOEXCEPT
1223       {
1224 	__glibcxx_requires_nonempty();
1225 	--this->_M_impl._M_finish;
1226 	_Alloc_traits::destroy(this->_M_impl, this->_M_impl._M_finish);
1227 	_GLIBCXX_ASAN_ANNOTATE_SHRINK(1);
1228       }
1229 
1230 #if __cplusplus >= 201103L
1231       /**
1232        *  @brief  Inserts an object in %vector before specified iterator.
1233        *  @param  __position  A const_iterator into the %vector.
1234        *  @param  __args  Arguments.
1235        *  @return  An iterator that points to the inserted data.
1236        *
1237        *  This function will insert an object of type T constructed
1238        *  with T(std::forward<Args>(args)...) before the specified location.
1239        *  Note that this kind of operation could be expensive for a %vector
1240        *  and if it is frequently used the user should consider using
1241        *  std::list.
1242        */
1243       template<typename... _Args>
1244 	iterator
1245 	emplace(const_iterator __position, _Args&&... __args)
1246 	{ return _M_emplace_aux(__position, std::forward<_Args>(__args)...); }
1247 
1248       /**
1249        *  @brief  Inserts given value into %vector before specified iterator.
1250        *  @param  __position  A const_iterator into the %vector.
1251        *  @param  __x  Data to be inserted.
1252        *  @return  An iterator that points to the inserted data.
1253        *
1254        *  This function will insert a copy of the given value before
1255        *  the specified location.  Note that this kind of operation
1256        *  could be expensive for a %vector and if it is frequently
1257        *  used the user should consider using std::list.
1258        */
1259       iterator
1260       insert(const_iterator __position, const value_type& __x);
1261 #else
1262       /**
1263        *  @brief  Inserts given value into %vector before specified iterator.
1264        *  @param  __position  An iterator into the %vector.
1265        *  @param  __x  Data to be inserted.
1266        *  @return  An iterator that points to the inserted data.
1267        *
1268        *  This function will insert a copy of the given value before
1269        *  the specified location.  Note that this kind of operation
1270        *  could be expensive for a %vector and if it is frequently
1271        *  used the user should consider using std::list.
1272        */
1273       iterator
1274       insert(iterator __position, const value_type& __x);
1275 #endif
1276 
1277 #if __cplusplus >= 201103L
1278       /**
1279        *  @brief  Inserts given rvalue into %vector before specified iterator.
1280        *  @param  __position  A const_iterator into the %vector.
1281        *  @param  __x  Data to be inserted.
1282        *  @return  An iterator that points to the inserted data.
1283        *
1284        *  This function will insert a copy of the given rvalue before
1285        *  the specified location.  Note that this kind of operation
1286        *  could be expensive for a %vector and if it is frequently
1287        *  used the user should consider using std::list.
1288        */
1289       iterator
1290       insert(const_iterator __position, value_type&& __x)
1291       { return _M_insert_rval(__position, std::move(__x)); }
1292 
1293       /**
1294        *  @brief  Inserts an initializer_list into the %vector.
1295        *  @param  __position  An iterator into the %vector.
1296        *  @param  __l  An initializer_list.
1297        *
1298        *  This function will insert copies of the data in the
1299        *  initializer_list @a l into the %vector before the location
1300        *  specified by @a position.
1301        *
1302        *  Note that this kind of operation could be expensive for a
1303        *  %vector and if it is frequently used the user should
1304        *  consider using std::list.
1305        */
1306       iterator
1307       insert(const_iterator __position, initializer_list<value_type> __l)
1308       {
1309 	auto __offset = __position - cbegin();
1310 	_M_range_insert(begin() + __offset, __l.begin(), __l.end(),
1311 			std::random_access_iterator_tag());
1312 	return begin() + __offset;
1313       }
1314 #endif
1315 
1316 #if __cplusplus >= 201103L
1317       /**
1318        *  @brief  Inserts a number of copies of given data into the %vector.
1319        *  @param  __position  A const_iterator into the %vector.
1320        *  @param  __n  Number of elements to be inserted.
1321        *  @param  __x  Data to be inserted.
1322        *  @return  An iterator that points to the inserted data.
1323        *
1324        *  This function will insert a specified number of copies of
1325        *  the given data before the location specified by @a position.
1326        *
1327        *  Note that this kind of operation could be expensive for a
1328        *  %vector and if it is frequently used the user should
1329        *  consider using std::list.
1330        */
1331       iterator
1332       insert(const_iterator __position, size_type __n, const value_type& __x)
1333       {
1334 	difference_type __offset = __position - cbegin();
1335 	_M_fill_insert(begin() + __offset, __n, __x);
1336 	return begin() + __offset;
1337       }
1338 #else
1339       /**
1340        *  @brief  Inserts a number of copies of given data into the %vector.
1341        *  @param  __position  An iterator into the %vector.
1342        *  @param  __n  Number of elements to be inserted.
1343        *  @param  __x  Data to be inserted.
1344        *
1345        *  This function will insert a specified number of copies of
1346        *  the given data before the location specified by @a position.
1347        *
1348        *  Note that this kind of operation could be expensive for a
1349        *  %vector and if it is frequently used the user should
1350        *  consider using std::list.
1351        */
1352       void
1353       insert(iterator __position, size_type __n, const value_type& __x)
1354       { _M_fill_insert(__position, __n, __x); }
1355 #endif
1356 
1357 #if __cplusplus >= 201103L
1358       /**
1359        *  @brief  Inserts a range into the %vector.
1360        *  @param  __position  A const_iterator into the %vector.
1361        *  @param  __first  An input iterator.
1362        *  @param  __last   An input iterator.
1363        *  @return  An iterator that points to the inserted data.
1364        *
1365        *  This function will insert copies of the data in the range
1366        *  [__first,__last) into the %vector before the location specified
1367        *  by @a pos.
1368        *
1369        *  Note that this kind of operation could be expensive for a
1370        *  %vector and if it is frequently used the user should
1371        *  consider using std::list.
1372        */
1373       template<typename _InputIterator,
1374 	       typename = std::_RequireInputIter<_InputIterator>>
1375 	iterator
1376 	insert(const_iterator __position, _InputIterator __first,
1377 	       _InputIterator __last)
1378 	{
1379 	  difference_type __offset = __position - cbegin();
1380 	  _M_insert_dispatch(begin() + __offset,
1381 			     __first, __last, __false_type());
1382 	  return begin() + __offset;
1383 	}
1384 #else
1385       /**
1386        *  @brief  Inserts a range into the %vector.
1387        *  @param  __position  An iterator into the %vector.
1388        *  @param  __first  An input iterator.
1389        *  @param  __last   An input iterator.
1390        *
1391        *  This function will insert copies of the data in the range
1392        *  [__first,__last) into the %vector before the location specified
1393        *  by @a pos.
1394        *
1395        *  Note that this kind of operation could be expensive for a
1396        *  %vector and if it is frequently used the user should
1397        *  consider using std::list.
1398        */
1399       template<typename _InputIterator>
1400 	void
1401 	insert(iterator __position, _InputIterator __first,
1402 	       _InputIterator __last)
1403 	{
1404 	  // Check whether it's an integral type.  If so, it's not an iterator.
1405 	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
1406 	  _M_insert_dispatch(__position, __first, __last, _Integral());
1407 	}
1408 #endif
1409 
1410       /**
1411        *  @brief  Remove element at given position.
1412        *  @param  __position  Iterator pointing to element to be erased.
1413        *  @return  An iterator pointing to the next element (or end()).
1414        *
1415        *  This function will erase the element at the given position and thus
1416        *  shorten the %vector by one.
1417        *
1418        *  Note This operation could be expensive and if it is
1419        *  frequently used the user should consider using std::list.
1420        *  The user is also cautioned that this function only erases
1421        *  the element, and that if the element is itself a pointer,
1422        *  the pointed-to memory is not touched in any way.  Managing
1423        *  the pointer is the user's responsibility.
1424        */
1425       iterator
1426 #if __cplusplus >= 201103L
1427       erase(const_iterator __position)
1428       { return _M_erase(begin() + (__position - cbegin())); }
1429 #else
1430       erase(iterator __position)
1431       { return _M_erase(__position); }
1432 #endif
1433 
1434       /**
1435        *  @brief  Remove a range of elements.
1436        *  @param  __first  Iterator pointing to the first element to be erased.
1437        *  @param  __last  Iterator pointing to one past the last element to be
1438        *                  erased.
1439        *  @return  An iterator pointing to the element pointed to by @a __last
1440        *           prior to erasing (or end()).
1441        *
1442        *  This function will erase the elements in the range
1443        *  [__first,__last) and shorten the %vector accordingly.
1444        *
1445        *  Note This operation could be expensive and if it is
1446        *  frequently used the user should consider using std::list.
1447        *  The user is also cautioned that this function only erases
1448        *  the elements, and that if the elements themselves are
1449        *  pointers, the pointed-to memory is not touched in any way.
1450        *  Managing the pointer is the user's responsibility.
1451        */
1452       iterator
1453 #if __cplusplus >= 201103L
1454       erase(const_iterator __first, const_iterator __last)
1455       {
1456 	const auto __beg = begin();
1457 	const auto __cbeg = cbegin();
1458 	return _M_erase(__beg + (__first - __cbeg), __beg + (__last - __cbeg));
1459       }
1460 #else
1461       erase(iterator __first, iterator __last)
1462       { return _M_erase(__first, __last); }
1463 #endif
1464 
1465       /**
1466        *  @brief  Swaps data with another %vector.
1467        *  @param  __x  A %vector of the same element and allocator types.
1468        *
1469        *  This exchanges the elements between two vectors in constant time.
1470        *  (Three pointers, so it should be quite fast.)
1471        *  Note that the global std::swap() function is specialized such that
1472        *  std::swap(v1,v2) will feed to this function.
1473        *
1474        *  Whether the allocators are swapped depends on the allocator traits.
1475        */
1476       void
1477       swap(vector& __x) _GLIBCXX_NOEXCEPT
1478       {
1479 #if __cplusplus >= 201103L
1480 	__glibcxx_assert(_Alloc_traits::propagate_on_container_swap::value
1481 			 || _M_get_Tp_allocator() == __x._M_get_Tp_allocator());
1482 #endif
1483 	this->_M_impl._M_swap_data(__x._M_impl);
1484 	_Alloc_traits::_S_on_swap(_M_get_Tp_allocator(),
1485 				  __x._M_get_Tp_allocator());
1486       }
1487 
1488       /**
1489        *  Erases all the elements.  Note that this function only erases the
1490        *  elements, and that if the elements themselves are pointers, the
1491        *  pointed-to memory is not touched in any way.  Managing the pointer is
1492        *  the user's responsibility.
1493        */
1494       void
1495       clear() _GLIBCXX_NOEXCEPT
1496       { _M_erase_at_end(this->_M_impl._M_start); }
1497 
1498     protected:
1499       /**
1500        *  Memory expansion handler.  Uses the member allocation function to
1501        *  obtain @a n bytes of memory, and then copies [first,last) into it.
1502        */
1503       template<typename _ForwardIterator>
1504 	pointer
1505 	_M_allocate_and_copy(size_type __n,
1506 			     _ForwardIterator __first, _ForwardIterator __last)
1507 	{
1508 	  pointer __result = this->_M_allocate(__n);
1509 	  __try
1510 	    {
1511 	      std::__uninitialized_copy_a(__first, __last, __result,
1512 					  _M_get_Tp_allocator());
1513 	      return __result;
1514 	    }
1515 	  __catch(...)
1516 	    {
1517 	      _M_deallocate(__result, __n);
1518 	      __throw_exception_again;
1519 	    }
1520 	}
1521 
1522 
1523       // Internal constructor functions follow.
1524 
1525       // Called by the range constructor to implement [23.1.1]/9
1526 
1527 #if __cplusplus < 201103L
1528       // _GLIBCXX_RESOLVE_LIB_DEFECTS
1529       // 438. Ambiguity in the "do the right thing" clause
1530       template<typename _Integer>
1531 	void
1532 	_M_initialize_dispatch(_Integer __n, _Integer __value, __true_type)
1533 	{
1534 	  this->_M_impl._M_start = _M_allocate(_S_check_init_len(
1535 		static_cast<size_type>(__n), _M_get_Tp_allocator()));
1536 	  this->_M_impl._M_end_of_storage =
1537 	    this->_M_impl._M_start + static_cast<size_type>(__n);
1538 	  _M_fill_initialize(static_cast<size_type>(__n), __value);
1539 	}
1540 
1541       // Called by the range constructor to implement [23.1.1]/9
1542       template<typename _InputIterator>
1543 	void
1544 	_M_initialize_dispatch(_InputIterator __first, _InputIterator __last,
1545 			       __false_type)
1546 	{
1547 	  _M_range_initialize(__first, __last,
1548 			      std::__iterator_category(__first));
1549 	}
1550 #endif
1551 
1552       // Called by the second initialize_dispatch above
1553       template<typename _InputIterator>
1554 	void
1555 	_M_range_initialize(_InputIterator __first, _InputIterator __last,
1556 			    std::input_iterator_tag)
1557 	{
1558 	  __try {
1559 	    for (; __first != __last; ++__first)
1560 #if __cplusplus >= 201103L
1561 	      emplace_back(*__first);
1562 #else
1563 	      push_back(*__first);
1564 #endif
1565 	  } __catch(...) {
1566 	    clear();
1567 	    __throw_exception_again;
1568 	  }
1569 	}
1570 
1571       // Called by the second initialize_dispatch above
1572       template<typename _ForwardIterator>
1573 	void
1574 	_M_range_initialize(_ForwardIterator __first, _ForwardIterator __last,
1575 			    std::forward_iterator_tag)
1576 	{
1577 	  const size_type __n = std::distance(__first, __last);
1578 	  this->_M_impl._M_start
1579 	    = this->_M_allocate(_S_check_init_len(__n, _M_get_Tp_allocator()));
1580 	  this->_M_impl._M_end_of_storage = this->_M_impl._M_start + __n;
1581 	  this->_M_impl._M_finish =
1582 	    std::__uninitialized_copy_a(__first, __last,
1583 					this->_M_impl._M_start,
1584 					_M_get_Tp_allocator());
1585 	}
1586 
1587       // Called by the first initialize_dispatch above and by the
1588       // vector(n,value,a) constructor.
1589       void
1590       _M_fill_initialize(size_type __n, const value_type& __value)
1591       {
1592 	this->_M_impl._M_finish =
1593 	  std::__uninitialized_fill_n_a(this->_M_impl._M_start, __n, __value,
1594 					_M_get_Tp_allocator());
1595       }
1596 
1597 #if __cplusplus >= 201103L
1598       // Called by the vector(n) constructor.
1599       void
1600       _M_default_initialize(size_type __n)
1601       {
1602 	this->_M_impl._M_finish =
1603 	  std::__uninitialized_default_n_a(this->_M_impl._M_start, __n,
1604 					   _M_get_Tp_allocator());
1605       }
1606 #endif
1607 
1608       // Internal assign functions follow.  The *_aux functions do the actual
1609       // assignment work for the range versions.
1610 
1611       // Called by the range assign to implement [23.1.1]/9
1612 
1613       // _GLIBCXX_RESOLVE_LIB_DEFECTS
1614       // 438. Ambiguity in the "do the right thing" clause
1615       template<typename _Integer>
1616 	void
1617 	_M_assign_dispatch(_Integer __n, _Integer __val, __true_type)
1618 	{ _M_fill_assign(__n, __val); }
1619 
1620       // Called by the range assign to implement [23.1.1]/9
1621       template<typename _InputIterator>
1622 	void
1623 	_M_assign_dispatch(_InputIterator __first, _InputIterator __last,
1624 			   __false_type)
1625 	{ _M_assign_aux(__first, __last, std::__iterator_category(__first)); }
1626 
1627       // Called by the second assign_dispatch above
1628       template<typename _InputIterator>
1629 	void
1630 	_M_assign_aux(_InputIterator __first, _InputIterator __last,
1631 		      std::input_iterator_tag);
1632 
1633       // Called by the second assign_dispatch above
1634       template<typename _ForwardIterator>
1635 	void
1636 	_M_assign_aux(_ForwardIterator __first, _ForwardIterator __last,
1637 		      std::forward_iterator_tag);
1638 
1639       // Called by assign(n,t), and the range assign when it turns out
1640       // to be the same thing.
1641       void
1642       _M_fill_assign(size_type __n, const value_type& __val);
1643 
1644       // Internal insert functions follow.
1645 
1646       // Called by the range insert to implement [23.1.1]/9
1647 
1648       // _GLIBCXX_RESOLVE_LIB_DEFECTS
1649       // 438. Ambiguity in the "do the right thing" clause
1650       template<typename _Integer>
1651 	void
1652 	_M_insert_dispatch(iterator __pos, _Integer __n, _Integer __val,
1653 			   __true_type)
1654 	{ _M_fill_insert(__pos, __n, __val); }
1655 
1656       // Called by the range insert to implement [23.1.1]/9
1657       template<typename _InputIterator>
1658 	void
1659 	_M_insert_dispatch(iterator __pos, _InputIterator __first,
1660 			   _InputIterator __last, __false_type)
1661 	{
1662 	  _M_range_insert(__pos, __first, __last,
1663 			  std::__iterator_category(__first));
1664 	}
1665 
1666       // Called by the second insert_dispatch above
1667       template<typename _InputIterator>
1668 	void
1669 	_M_range_insert(iterator __pos, _InputIterator __first,
1670 			_InputIterator __last, std::input_iterator_tag);
1671 
1672       // Called by the second insert_dispatch above
1673       template<typename _ForwardIterator>
1674 	void
1675 	_M_range_insert(iterator __pos, _ForwardIterator __first,
1676 			_ForwardIterator __last, std::forward_iterator_tag);
1677 
1678       // Called by insert(p,n,x), and the range insert when it turns out to be
1679       // the same thing.
1680       void
1681       _M_fill_insert(iterator __pos, size_type __n, const value_type& __x);
1682 
1683 #if __cplusplus >= 201103L
1684       // Called by resize(n).
1685       void
1686       _M_default_append(size_type __n);
1687 
1688       bool
1689       _M_shrink_to_fit();
1690 #endif
1691 
1692 #if __cplusplus < 201103L
1693       // Called by insert(p,x)
1694       void
1695       _M_insert_aux(iterator __position, const value_type& __x);
1696 
1697       void
1698       _M_realloc_insert(iterator __position, const value_type& __x);
1699 #else
1700       // A value_type object constructed with _Alloc_traits::construct()
1701       // and destroyed with _Alloc_traits::destroy().
1702       struct _Temporary_value
1703       {
1704 	template<typename... _Args>
1705 	  explicit
1706 	  _Temporary_value(vector* __vec, _Args&&... __args) : _M_this(__vec)
1707 	  {
1708 	    _Alloc_traits::construct(_M_this->_M_impl, _M_ptr(),
1709 				     std::forward<_Args>(__args)...);
1710 	  }
1711 
1712 	~_Temporary_value()
1713 	{ _Alloc_traits::destroy(_M_this->_M_impl, _M_ptr()); }
1714 
1715 	value_type&
1716 	_M_val() { return *_M_ptr(); }
1717 
1718       private:
1719 	_Tp*
1720 	_M_ptr() { return reinterpret_cast<_Tp*>(&__buf); }
1721 
1722 	vector* _M_this;
1723 	typename aligned_storage<sizeof(_Tp), alignof(_Tp)>::type __buf;
1724       };
1725 
1726       // Called by insert(p,x) and other functions when insertion needs to
1727       // reallocate or move existing elements. _Arg is either _Tp& or _Tp.
1728       template<typename _Arg>
1729 	void
1730 	_M_insert_aux(iterator __position, _Arg&& __arg);
1731 
1732       template<typename... _Args>
1733 	void
1734 	_M_realloc_insert(iterator __position, _Args&&... __args);
1735 
1736       // Either move-construct at the end, or forward to _M_insert_aux.
1737       iterator
1738       _M_insert_rval(const_iterator __position, value_type&& __v);
1739 
1740       // Try to emplace at the end, otherwise forward to _M_insert_aux.
1741       template<typename... _Args>
1742 	iterator
1743 	_M_emplace_aux(const_iterator __position, _Args&&... __args);
1744 
1745       // Emplacing an rvalue of the correct type can use _M_insert_rval.
1746       iterator
1747       _M_emplace_aux(const_iterator __position, value_type&& __v)
1748       { return _M_insert_rval(__position, std::move(__v)); }
1749 #endif
1750 
1751       // Called by _M_fill_insert, _M_insert_aux etc.
1752       size_type
1753       _M_check_len(size_type __n, const char* __s) const
1754       {
1755 	if (max_size() - size() < __n)
1756 	  __throw_length_error(__N(__s));
1757 
1758 	const size_type __len = size() + (std::max)(size(), __n);
1759 	return (__len < size() || __len > max_size()) ? max_size() : __len;
1760       }
1761 
1762       // Called by constructors to check initial size.
1763       static size_type
1764       _S_check_init_len(size_type __n, const allocator_type& __a)
1765       {
1766 	if (__n > _S_max_size(_Tp_alloc_type(__a)))
1767 	  __throw_length_error(
1768 	      __N("cannot create std::vector larger than max_size()"));
1769 	return __n;
1770       }
1771 
1772       static size_type
1773       _S_max_size(const _Tp_alloc_type& __a) _GLIBCXX_NOEXCEPT
1774       {
1775 	// std::distance(begin(), end()) cannot be greater than PTRDIFF_MAX,
1776 	// and realistically we can't store more than PTRDIFF_MAX/sizeof(T)
1777 	// (even if std::allocator_traits::max_size says we can).
1778 	const size_t __diffmax
1779 	  = __gnu_cxx::__numeric_traits<ptrdiff_t>::__max / sizeof(_Tp);
1780 	const size_t __allocmax = _Alloc_traits::max_size(__a);
1781 	return (std::min)(__diffmax, __allocmax);
1782       }
1783 
1784       // Internal erase functions follow.
1785 
1786       // Called by erase(q1,q2), clear(), resize(), _M_fill_assign,
1787       // _M_assign_aux.
1788       void
1789       _M_erase_at_end(pointer __pos) _GLIBCXX_NOEXCEPT
1790       {
1791 	if (size_type __n = this->_M_impl._M_finish - __pos)
1792 	  {
1793 	    std::_Destroy(__pos, this->_M_impl._M_finish,
1794 			  _M_get_Tp_allocator());
1795 	    this->_M_impl._M_finish = __pos;
1796 	    _GLIBCXX_ASAN_ANNOTATE_SHRINK(__n);
1797 	  }
1798       }
1799 
1800       iterator
1801       _M_erase(iterator __position);
1802 
1803       iterator
1804       _M_erase(iterator __first, iterator __last);
1805 
1806 #if __cplusplus >= 201103L
1807     private:
1808       // Constant-time move assignment when source object's memory can be
1809       // moved, either because the source's allocator will move too
1810       // or because the allocators are equal.
1811       void
1812       _M_move_assign(vector&& __x, true_type) noexcept
1813       {
1814 	vector __tmp(get_allocator());
1815 	this->_M_impl._M_swap_data(__x._M_impl);
1816 	__tmp._M_impl._M_swap_data(__x._M_impl);
1817 	std::__alloc_on_move(_M_get_Tp_allocator(), __x._M_get_Tp_allocator());
1818       }
1819 
1820       // Do move assignment when it might not be possible to move source
1821       // object's memory, resulting in a linear-time operation.
1822       void
1823       _M_move_assign(vector&& __x, false_type)
1824       {
1825 	if (__x._M_get_Tp_allocator() == this->_M_get_Tp_allocator())
1826 	  _M_move_assign(std::move(__x), true_type());
1827 	else
1828 	  {
1829 	    // The rvalue's allocator cannot be moved and is not equal,
1830 	    // so we need to individually move each element.
1831 	    this->assign(std::__make_move_if_noexcept_iterator(__x.begin()),
1832 			 std::__make_move_if_noexcept_iterator(__x.end()));
1833 	    __x.clear();
1834 	  }
1835       }
1836 #endif
1837 
1838       template<typename _Up>
1839 	_Up*
1840 	_M_data_ptr(_Up* __ptr) const _GLIBCXX_NOEXCEPT
1841 	{ return __ptr; }
1842 
1843 #if __cplusplus >= 201103L
1844       template<typename _Ptr>
1845 	typename std::pointer_traits<_Ptr>::element_type*
1846 	_M_data_ptr(_Ptr __ptr) const
1847 	{ return empty() ? nullptr : std::__to_address(__ptr); }
1848 #else
1849       template<typename _Up>
1850 	_Up*
1851 	_M_data_ptr(_Up* __ptr) _GLIBCXX_NOEXCEPT
1852 	{ return __ptr; }
1853 
1854       template<typename _Ptr>
1855 	value_type*
1856 	_M_data_ptr(_Ptr __ptr)
1857 	{ return empty() ? (value_type*)0 : __ptr.operator->(); }
1858 
1859       template<typename _Ptr>
1860 	const value_type*
1861 	_M_data_ptr(_Ptr __ptr) const
1862 	{ return empty() ? (const value_type*)0 : __ptr.operator->(); }
1863 #endif
1864     };
1865 
1866 #if __cpp_deduction_guides >= 201606
1867   template<typename _InputIterator, typename _ValT
1868 	     = typename iterator_traits<_InputIterator>::value_type,
1869 	   typename _Allocator = allocator<_ValT>,
1870 	   typename = _RequireInputIter<_InputIterator>,
1871 	   typename = _RequireAllocator<_Allocator>>
1872     vector(_InputIterator, _InputIterator, _Allocator = _Allocator())
1873       -> vector<_ValT, _Allocator>;
1874 #endif
1875 
1876   /**
1877    *  @brief  Vector equality comparison.
1878    *  @param  __x  A %vector.
1879    *  @param  __y  A %vector of the same type as @a __x.
1880    *  @return  True iff the size and elements of the vectors are equal.
1881    *
1882    *  This is an equivalence relation.  It is linear in the size of the
1883    *  vectors.  Vectors are considered equivalent if their sizes are equal,
1884    *  and if corresponding elements compare equal.
1885   */
1886   template<typename _Tp, typename _Alloc>
1887     inline bool
1888     operator==(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
1889     { return (__x.size() == __y.size()
1890 	      && std::equal(__x.begin(), __x.end(), __y.begin())); }
1891 
1892   /**
1893    *  @brief  Vector ordering relation.
1894    *  @param  __x  A %vector.
1895    *  @param  __y  A %vector of the same type as @a __x.
1896    *  @return  True iff @a __x is lexicographically less than @a __y.
1897    *
1898    *  This is a total ordering relation.  It is linear in the size of the
1899    *  vectors.  The elements must be comparable with @c <.
1900    *
1901    *  See std::lexicographical_compare() for how the determination is made.
1902   */
1903   template<typename _Tp, typename _Alloc>
1904     inline bool
1905     operator<(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
1906     { return std::lexicographical_compare(__x.begin(), __x.end(),
1907 					  __y.begin(), __y.end()); }
1908 
1909   /// Based on operator==
1910   template<typename _Tp, typename _Alloc>
1911     inline bool
1912     operator!=(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
1913     { return !(__x == __y); }
1914 
1915   /// Based on operator<
1916   template<typename _Tp, typename _Alloc>
1917     inline bool
1918     operator>(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
1919     { return __y < __x; }
1920 
1921   /// Based on operator<
1922   template<typename _Tp, typename _Alloc>
1923     inline bool
1924     operator<=(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
1925     { return !(__y < __x); }
1926 
1927   /// Based on operator<
1928   template<typename _Tp, typename _Alloc>
1929     inline bool
1930     operator>=(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
1931     { return !(__x < __y); }
1932 
1933   /// See std::vector::swap().
1934   template<typename _Tp, typename _Alloc>
1935     inline void
1936     swap(vector<_Tp, _Alloc>& __x, vector<_Tp, _Alloc>& __y)
1937     _GLIBCXX_NOEXCEPT_IF(noexcept(__x.swap(__y)))
1938     { __x.swap(__y); }
1939 
1940 _GLIBCXX_END_NAMESPACE_CONTAINER
1941 
1942 #if __cplusplus >= 201703L
1943   namespace __detail::__variant
1944   {
1945     template<typename> struct _Never_valueless_alt; // see <variant>
1946 
1947     // Provide the strong exception-safety guarantee when emplacing a
1948     // vector into a variant, but only if move assignment cannot throw.
1949     template<typename _Tp, typename _Alloc>
1950       struct _Never_valueless_alt<_GLIBCXX_STD_C::vector<_Tp, _Alloc>>
1951       : std::is_nothrow_move_assignable<_GLIBCXX_STD_C::vector<_Tp, _Alloc>>
1952       { };
1953   }  // namespace __detail::__variant
1954 #endif // C++17
1955 
1956 _GLIBCXX_END_NAMESPACE_VERSION
1957 } // namespace std
1958 
1959 #endif /* _STL_VECTOR_H */
1960