1 // vector<bool> specialization -*- C++ -*-
2 
3 // Copyright (C) 2001-2022 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) 1996-1999
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_bvector.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_BVECTOR_H
57 #define _STL_BVECTOR_H 1
58 
59 #if __cplusplus >= 201103L
60 #include <initializer_list>
61 #include <bits/functional_hash.h>
62 #endif
63 
_GLIBCXX_VISIBILITY(default)64 namespace std _GLIBCXX_VISIBILITY(default)
65 {
66 _GLIBCXX_BEGIN_NAMESPACE_VERSION
67 
68   typedef unsigned long _Bit_type;
69   enum { _S_word_bit = int(__CHAR_BIT__ * sizeof(_Bit_type)) };
70 
71   __attribute__((__nonnull__))
72   _GLIBCXX20_CONSTEXPR
73   void
74   __fill_bvector_n(_Bit_type*, size_t, bool) _GLIBCXX_NOEXCEPT;
75 
76 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
77 
78   struct _Bit_reference
79   {
80     _Bit_type * _M_p;
81     _Bit_type _M_mask;
82 
83     _GLIBCXX20_CONSTEXPR
84     _Bit_reference(_Bit_type * __x, _Bit_type __y)
85     : _M_p(__x), _M_mask(__y) { }
86 
87     _GLIBCXX20_CONSTEXPR
88     _Bit_reference() _GLIBCXX_NOEXCEPT : _M_p(0), _M_mask(0) { }
89 
90 #if __cplusplus >= 201103L
91     _Bit_reference(const _Bit_reference&) = default;
92 #endif
93 
94     _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
95     operator bool() const _GLIBCXX_NOEXCEPT
96     { return !!(*_M_p & _M_mask); }
97 
98     _GLIBCXX20_CONSTEXPR
99     _Bit_reference&
100     operator=(bool __x) _GLIBCXX_NOEXCEPT
101     {
102       if (__x)
103           *_M_p |= _M_mask;
104       else
105           *_M_p &= ~_M_mask;
106       return *this;
107     }
108 
109     _GLIBCXX20_CONSTEXPR
110     _Bit_reference&
111     operator=(const _Bit_reference& __x) _GLIBCXX_NOEXCEPT
112     { return *this = bool(__x); }
113 
114     _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
115     bool
116     operator==(const _Bit_reference& __x) const
117     { return bool(*this) == bool(__x); }
118 
119     _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
120     bool
121     operator<(const _Bit_reference& __x) const
122     { return !bool(*this) && bool(__x); }
123 
124     _GLIBCXX20_CONSTEXPR
125     void
126     flip() _GLIBCXX_NOEXCEPT
127     { *_M_p ^= _M_mask; }
128 
129 #if __cplusplus >= 201103L
130     _GLIBCXX20_CONSTEXPR
131     friend void
132     swap(_Bit_reference __x, _Bit_reference __y) noexcept
133     {
134       bool __tmp = __x;
135       __x = __y;
136       __y = __tmp;
137     }
138 
139     _GLIBCXX20_CONSTEXPR
140     friend void
141     swap(_Bit_reference __x, bool& __y) noexcept
142     {
143       bool __tmp = __x;
144       __x = __y;
145       __y = __tmp;
146     }
147 
148     _GLIBCXX20_CONSTEXPR
149     friend void
150     swap(bool& __x, _Bit_reference __y) noexcept
151     {
152       bool __tmp = __x;
153       __x = __y;
154       __y = __tmp;
155     }
156 #endif
157   };
158 
159 // Ignore warnings about std::iterator.
160 #pragma GCC diagnostic push
161 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
162   struct _Bit_iterator_base
163   : public std::iterator<std::random_access_iterator_tag, bool>
164   {
165     _Bit_type * _M_p;
166     unsigned int _M_offset;
167 
168     _GLIBCXX20_CONSTEXPR
169     _Bit_iterator_base(_Bit_type * __x, unsigned int __y)
170     : _M_p(__x), _M_offset(__y) { }
171 
172     _GLIBCXX20_CONSTEXPR
173     void
174     _M_bump_up()
175     {
176       if (_M_offset++ == int(_S_word_bit) - 1)
177           {
178             _M_offset = 0;
179             ++_M_p;
180           }
181     }
182 
183     _GLIBCXX20_CONSTEXPR
184     void
185     _M_bump_down()
186     {
187       if (_M_offset-- == 0)
188           {
189             _M_offset = int(_S_word_bit) - 1;
190             --_M_p;
191           }
192     }
193 
194     _GLIBCXX20_CONSTEXPR
195     void
196     _M_incr(ptrdiff_t __i)
197     {
198       difference_type __n = __i + _M_offset;
199       _M_p += __n / int(_S_word_bit);
200       __n = __n % int(_S_word_bit);
201       if (__n < 0)
202           {
203             __n += int(_S_word_bit);
204             --_M_p;
205           }
206       _M_offset = static_cast<unsigned int>(__n);
207     }
208 
209     _GLIBCXX_NODISCARD
210     friend _GLIBCXX20_CONSTEXPR bool
211     operator==(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
212     { return __x._M_p == __y._M_p && __x._M_offset == __y._M_offset; }
213 
214 #if __cpp_lib_three_way_comparison
215     [[nodiscard]]
216     friend constexpr strong_ordering
217     operator<=>(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
218     noexcept
219     {
220       if (const auto __cmp = __x._M_p <=> __y._M_p; __cmp != 0)
221           return __cmp;
222       return __x._M_offset <=> __y._M_offset;
223     }
224 #else
225     _GLIBCXX_NODISCARD
226     friend bool
227     operator<(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
228     {
229       return __x._M_p < __y._M_p
230               || (__x._M_p == __y._M_p && __x._M_offset < __y._M_offset);
231     }
232 
233     _GLIBCXX_NODISCARD
234     friend bool
235     operator!=(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
236     { return !(__x == __y); }
237 
238     _GLIBCXX_NODISCARD
239     friend bool
240     operator>(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
241     { return __y < __x; }
242 
243     _GLIBCXX_NODISCARD
244     friend bool
245     operator<=(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
246     { return !(__y < __x); }
247 
248     _GLIBCXX_NODISCARD
249     friend bool
250     operator>=(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
251     { return !(__x < __y); }
252 #endif // three-way comparison
253 
254     friend _GLIBCXX20_CONSTEXPR ptrdiff_t
255     operator-(const _Bit_iterator_base& __x, const _Bit_iterator_base& __y)
256     {
257       return (int(_S_word_bit) * (__x._M_p - __y._M_p)
258                 + __x._M_offset - __y._M_offset);
259     }
260   };
261 #pragma GCC diagnostic pop
262 
263   struct _Bit_iterator : public _Bit_iterator_base
264   {
265     typedef _Bit_reference  reference;
266 #if __cplusplus > 201703L
267     typedef void        pointer;
268 #else
269     typedef _Bit_reference* pointer;
270 #endif
271     typedef _Bit_iterator   iterator;
272 
273     _GLIBCXX20_CONSTEXPR
274     _Bit_iterator() : _Bit_iterator_base(0, 0) { }
275 
276     _GLIBCXX20_CONSTEXPR
277     _Bit_iterator(_Bit_type * __x, unsigned int __y)
278     : _Bit_iterator_base(__x, __y) { }
279 
280     _GLIBCXX20_CONSTEXPR
281     iterator
282     _M_const_cast() const
283     { return *this; }
284 
285     _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
286     reference
287     operator*() const
288     { return reference(_M_p, 1UL << _M_offset); }
289 
290     _GLIBCXX20_CONSTEXPR
291     iterator&
292     operator++()
293     {
294       _M_bump_up();
295       return *this;
296     }
297 
298     _GLIBCXX20_CONSTEXPR
299     iterator
300     operator++(int)
301     {
302       iterator __tmp = *this;
303       _M_bump_up();
304       return __tmp;
305     }
306 
307     _GLIBCXX20_CONSTEXPR
308     iterator&
309     operator--()
310     {
311       _M_bump_down();
312       return *this;
313     }
314 
315     _GLIBCXX20_CONSTEXPR
316     iterator
317     operator--(int)
318     {
319       iterator __tmp = *this;
320       _M_bump_down();
321       return __tmp;
322     }
323 
324     _GLIBCXX20_CONSTEXPR
325     iterator&
326     operator+=(difference_type __i)
327     {
328       _M_incr(__i);
329       return *this;
330     }
331 
332     _GLIBCXX20_CONSTEXPR
333     iterator&
334     operator-=(difference_type __i)
335     {
336       *this += -__i;
337       return *this;
338     }
339 
340     _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
341     reference
342     operator[](difference_type __i) const
343     { return *(*this + __i); }
344 
345     _GLIBCXX_NODISCARD
346     friend _GLIBCXX20_CONSTEXPR iterator
347     operator+(const iterator& __x, difference_type __n)
348     {
349       iterator __tmp = __x;
350       __tmp += __n;
351       return __tmp;
352     }
353 
354     _GLIBCXX_NODISCARD
355     friend _GLIBCXX20_CONSTEXPR iterator
356     operator+(difference_type __n, const iterator& __x)
357     { return __x + __n; }
358 
359     _GLIBCXX_NODISCARD
360     friend _GLIBCXX20_CONSTEXPR iterator
361     operator-(const iterator& __x, difference_type __n)
362     {
363       iterator __tmp = __x;
364       __tmp -= __n;
365       return __tmp;
366     }
367   };
368 
369   struct _Bit_const_iterator : public _Bit_iterator_base
370   {
371     typedef bool                 reference;
372     typedef bool                 const_reference;
373 #if __cplusplus > 201703L
374     typedef void        pointer;
375 #else
376     typedef const bool*          pointer;
377 #endif
378     typedef _Bit_const_iterator  const_iterator;
379 
380     _GLIBCXX20_CONSTEXPR
381     _Bit_const_iterator() : _Bit_iterator_base(0, 0) { }
382 
383     _GLIBCXX20_CONSTEXPR
384     _Bit_const_iterator(_Bit_type * __x, unsigned int __y)
385     : _Bit_iterator_base(__x, __y) { }
386 
387     _GLIBCXX20_CONSTEXPR
388     _Bit_const_iterator(const _Bit_iterator& __x)
389     : _Bit_iterator_base(__x._M_p, __x._M_offset) { }
390 
391     _GLIBCXX20_CONSTEXPR
392     _Bit_iterator
393     _M_const_cast() const
394     { return _Bit_iterator(_M_p, _M_offset); }
395 
396     _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
397     const_reference
398     operator*() const
399     { return _Bit_reference(_M_p, 1UL << _M_offset); }
400 
401     _GLIBCXX20_CONSTEXPR
402     const_iterator&
403     operator++()
404     {
405       _M_bump_up();
406       return *this;
407     }
408 
409     _GLIBCXX20_CONSTEXPR
410     const_iterator
411     operator++(int)
412     {
413       const_iterator __tmp = *this;
414       _M_bump_up();
415       return __tmp;
416     }
417 
418     _GLIBCXX20_CONSTEXPR
419     const_iterator&
420     operator--()
421     {
422       _M_bump_down();
423       return *this;
424     }
425 
426     _GLIBCXX20_CONSTEXPR
427     const_iterator
428     operator--(int)
429     {
430       const_iterator __tmp = *this;
431       _M_bump_down();
432       return __tmp;
433     }
434 
435     _GLIBCXX20_CONSTEXPR
436     const_iterator&
437     operator+=(difference_type __i)
438     {
439       _M_incr(__i);
440       return *this;
441     }
442 
443     _GLIBCXX20_CONSTEXPR
444     const_iterator&
445     operator-=(difference_type __i)
446     {
447       *this += -__i;
448       return *this;
449     }
450 
451     _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
452     const_reference
453     operator[](difference_type __i) const
454     { return *(*this + __i); }
455 
456     _GLIBCXX_NODISCARD
457     friend _GLIBCXX20_CONSTEXPR const_iterator
458     operator+(const const_iterator& __x, difference_type __n)
459     {
460       const_iterator __tmp = __x;
461       __tmp += __n;
462       return __tmp;
463     }
464 
465     _GLIBCXX_NODISCARD
466     friend _GLIBCXX20_CONSTEXPR const_iterator
467     operator-(const const_iterator& __x, difference_type __n)
468     {
469       const_iterator __tmp = __x;
470       __tmp -= __n;
471       return __tmp;
472     }
473 
474     _GLIBCXX_NODISCARD
475     friend _GLIBCXX20_CONSTEXPR const_iterator
476     operator+(difference_type __n, const const_iterator& __x)
477     { return __x + __n; }
478   };
479 
480   template<typename _Alloc>
481     struct _Bvector_base
482     {
483       typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
484         rebind<_Bit_type>::other _Bit_alloc_type;
485       typedef typename __gnu_cxx::__alloc_traits<_Bit_alloc_type>
486           _Bit_alloc_traits;
487       typedef typename _Bit_alloc_traits::pointer _Bit_pointer;
488 
489       struct _Bvector_impl_data
490       {
491 #if !_GLIBCXX_INLINE_VERSION
492           _Bit_iterator       _M_start;
493 #else
494           // We don't need the offset field for the start, it's always zero.
495           struct {
496             _Bit_type* _M_p;
497             // Allow assignment from iterators (assume offset is zero):
498             _GLIBCXX20_CONSTEXPR
499             void operator=(_Bit_iterator __it) { _M_p = __it._M_p; }
500           } _M_start;
501 #endif
502           _Bit_iterator       _M_finish;
503           _Bit_pointer        _M_end_of_storage;
504 
505           _GLIBCXX20_CONSTEXPR
506           _Bvector_impl_data() _GLIBCXX_NOEXCEPT
507           : _M_start(), _M_finish(), _M_end_of_storage()
508           { }
509 
510 #if __cplusplus >= 201103L
511           _Bvector_impl_data(const _Bvector_impl_data&) = default;
512 
513           _Bvector_impl_data&
514           operator=(const _Bvector_impl_data&) = default;
515 
516           _GLIBCXX20_CONSTEXPR
517           _Bvector_impl_data(_Bvector_impl_data&& __x) noexcept
518           : _Bvector_impl_data(__x)
519           { __x._M_reset(); }
520 
521           _GLIBCXX20_CONSTEXPR
522           void
523           _M_move_data(_Bvector_impl_data&& __x) noexcept
524           {
525             *this = __x;
526             __x._M_reset();
527           }
528 #endif
529 
530           _GLIBCXX20_CONSTEXPR
531           void
532           _M_reset() _GLIBCXX_NOEXCEPT
533           { *this = _Bvector_impl_data(); }
534 
535           _GLIBCXX20_CONSTEXPR
536           void
537           _M_swap_data(_Bvector_impl_data& __x) _GLIBCXX_NOEXCEPT
538           {
539             // Do not use std::swap(_M_start, __x._M_start), etc as it loses
540             // information used by TBAA.
541             std::swap(*this, __x);
542           }
543       };
544 
545       struct _Bvector_impl
546           : public _Bit_alloc_type, public _Bvector_impl_data
547       {
548           _GLIBCXX20_CONSTEXPR
549           _Bvector_impl() _GLIBCXX_NOEXCEPT_IF(
550             is_nothrow_default_constructible<_Bit_alloc_type>::value)
551           : _Bit_alloc_type()
552           { }
553 
554           _GLIBCXX20_CONSTEXPR
555           _Bvector_impl(const _Bit_alloc_type& __a) _GLIBCXX_NOEXCEPT
556           : _Bit_alloc_type(__a)
557           { }
558 
559 #if __cplusplus >= 201103L
560           // Not defaulted, to enforce noexcept(true) even when
561           // !is_nothrow_move_constructible<_Bit_alloc_type>.
562           _GLIBCXX20_CONSTEXPR
563           _Bvector_impl(_Bvector_impl&& __x) noexcept
564           : _Bit_alloc_type(std::move(__x)), _Bvector_impl_data(std::move(__x))
565           { }
566 
567           _GLIBCXX20_CONSTEXPR
568           _Bvector_impl(_Bit_alloc_type&& __a, _Bvector_impl&& __x) noexcept
569           : _Bit_alloc_type(std::move(__a)), _Bvector_impl_data(std::move(__x))
570           { }
571 #endif
572 
573           _GLIBCXX20_CONSTEXPR
574           _Bit_type*
575           _M_end_addr() const _GLIBCXX_NOEXCEPT
576           {
577             if (this->_M_end_of_storage)
578               return std::__addressof(this->_M_end_of_storage[-1]) + 1;
579             return 0;
580           }
581       };
582 
583     public:
584       typedef _Alloc allocator_type;
585 
586       _GLIBCXX20_CONSTEXPR
587       _Bit_alloc_type&
588       _M_get_Bit_allocator() _GLIBCXX_NOEXCEPT
589       { return this->_M_impl; }
590 
591       _GLIBCXX20_CONSTEXPR
592       const _Bit_alloc_type&
593       _M_get_Bit_allocator() const _GLIBCXX_NOEXCEPT
594       { return this->_M_impl; }
595 
596       _GLIBCXX20_CONSTEXPR
597       allocator_type
598       get_allocator() const _GLIBCXX_NOEXCEPT
599       { return allocator_type(_M_get_Bit_allocator()); }
600 
601 #if __cplusplus >= 201103L
602       _Bvector_base() = default;
603 #else
604       _Bvector_base() { }
605 #endif
606 
607       _GLIBCXX20_CONSTEXPR
608       _Bvector_base(const allocator_type& __a)
609       : _M_impl(__a) { }
610 
611 #if __cplusplus >= 201103L
612       _Bvector_base(_Bvector_base&&) = default;
613 
614       _GLIBCXX20_CONSTEXPR
615       _Bvector_base(_Bvector_base&& __x, const allocator_type& __a) noexcept
616       : _M_impl(_Bit_alloc_type(__a), std::move(__x._M_impl))
617       { }
618 #endif
619 
620       _GLIBCXX20_CONSTEXPR
621       ~_Bvector_base()
622       { this->_M_deallocate(); }
623 
624     protected:
625       _Bvector_impl _M_impl;
626 
627       _GLIBCXX20_CONSTEXPR
628       _Bit_pointer
629       _M_allocate(size_t __n)
630       {
631           _Bit_pointer __p = _Bit_alloc_traits::allocate(_M_impl, _S_nword(__n));
632 #if __cpp_lib_is_constant_evaluated && __cpp_constexpr_dynamic_alloc
633           if (std::is_constant_evaluated())
634             {
635               __n = _S_nword(__n);
636               for (size_t __i = 0; __i < __n; ++__i)
637                 std::construct_at(std::to_address(__p) + __i);
638             }
639 #endif
640           return __p;
641       }
642 
643       _GLIBCXX20_CONSTEXPR
644       void
645       _M_deallocate()
646       {
647           if (_M_impl._M_start._M_p)
648             {
649               const size_t __n = _M_impl._M_end_addr() - _M_impl._M_start._M_p;
650               _Bit_alloc_traits::deallocate(_M_impl,
651                                                     _M_impl._M_end_of_storage - __n,
652                                                     __n);
653               _M_impl._M_reset();
654             }
655       }
656 
657 #if __cplusplus >= 201103L
658       _GLIBCXX20_CONSTEXPR
659       void
660       _M_move_data(_Bvector_base&& __x) noexcept
661       { _M_impl._M_move_data(std::move(__x._M_impl)); }
662 #endif
663 
664       _GLIBCXX_CONSTEXPR
665       static size_t
666       _S_nword(size_t __n)
667       { return (__n + int(_S_word_bit) - 1) / int(_S_word_bit); }
668     };
669 
670   /**
671    *  @brief  A specialization of vector for booleans which offers fixed time
672    *  access to individual elements in any order.
673    *
674    *  @ingroup sequences
675    *  @headerfile vector
676    *  @since C++98
677    *
678    *  @tparam _Alloc  Allocator type.
679    *
680    *  Note that vector<bool> does not actually meet the requirements for being
681    *  a container.  This is because the reference and pointer types are not
682    *  really references and pointers to bool.  See DR96 for details.  @see
683    *  vector for function documentation.
684    *
685    *  In some terminology a %vector can be described as a dynamic
686    *  C-style array, it offers fast and efficient access to individual
687    *  elements in any order and saves the user from worrying about
688    *  memory and size allocation.  Subscripting ( @c [] ) access is
689    *  also provided as with C-style arrays.
690   */
691   template<typename _Alloc>
692     class vector<bool, _Alloc> : protected _Bvector_base<_Alloc>
693     {
694       typedef _Bvector_base<_Alloc>                         _Base;
695       typedef typename _Base::_Bit_pointer                  _Bit_pointer;
696       typedef typename _Base::_Bit_alloc_traits             _Bit_alloc_traits;
697 
698 #if __cplusplus >= 201103L
699       friend struct std::hash<vector>;
700 #endif
701 
702     public:
703       typedef bool                                          value_type;
704       typedef size_t                                                  size_type;
705       typedef ptrdiff_t                                               difference_type;
706       typedef _Bit_reference                                reference;
707       typedef bool                                          const_reference;
708       typedef _Bit_reference*                               pointer;
709       typedef const bool*                                   const_pointer;
710       typedef _Bit_iterator                                 iterator;
711       typedef _Bit_const_iterator                           const_iterator;
712       typedef std::reverse_iterator<const_iterator>         const_reverse_iterator;
713       typedef std::reverse_iterator<iterator>               reverse_iterator;
714       typedef _Alloc                                                  allocator_type;
715 
716       _GLIBCXX20_CONSTEXPR
717       allocator_type
718       get_allocator() const
719       { return _Base::get_allocator(); }
720 
721     protected:
722       using _Base::_M_allocate;
723       using _Base::_M_deallocate;
724       using _Base::_S_nword;
725       using _Base::_M_get_Bit_allocator;
726 
727     public:
728 #if __cplusplus >= 201103L
729       vector() = default;
730 #else
731       vector() { }
732 #endif
733 
734       _GLIBCXX20_CONSTEXPR
735       explicit
736       vector(const allocator_type& __a)
737       : _Base(__a) { }
738 
739 #if __cplusplus >= 201103L
740       _GLIBCXX20_CONSTEXPR
741       explicit
742       vector(size_type __n, const allocator_type& __a = allocator_type())
743       : vector(__n, false, __a)
744       { }
745 
746       _GLIBCXX20_CONSTEXPR
747       vector(size_type __n, const bool& __value,
748                const allocator_type& __a = allocator_type())
749 #else
750       explicit
751       vector(size_type __n, const bool& __value = bool(),
752                const allocator_type& __a = allocator_type())
753 #endif
754       : _Base(__a)
755       {
756           _M_initialize(__n);
757           _M_initialize_value(__value);
758       }
759 
760       _GLIBCXX20_CONSTEXPR
761       vector(const vector& __x)
762       : _Base(_Bit_alloc_traits::_S_select_on_copy(__x._M_get_Bit_allocator()))
763       {
764           _M_initialize(__x.size());
765           _M_copy_aligned(__x.begin(), __x.end(), begin());
766       }
767 
768 #if __cplusplus >= 201103L
769       vector(vector&&) = default;
770 
771     private:
772       _GLIBCXX20_CONSTEXPR
773       vector(vector&& __x, const allocator_type& __a, true_type) noexcept
774       : _Base(std::move(__x), __a)
775       { }
776 
777       _GLIBCXX20_CONSTEXPR
778       vector(vector&& __x, const allocator_type& __a, false_type)
779       : _Base(__a)
780       {
781           if (__x.get_allocator() == __a)
782             this->_M_move_data(std::move(__x));
783           else
784             {
785               _M_initialize(__x.size());
786               _M_copy_aligned(__x.begin(), __x.end(), begin());
787               __x.clear();
788             }
789       }
790 
791     public:
792       _GLIBCXX20_CONSTEXPR
793       vector(vector&& __x, const __type_identity_t<allocator_type>& __a)
794       noexcept(_Bit_alloc_traits::_S_always_equal())
795       : vector(std::move(__x), __a,
796                  typename _Bit_alloc_traits::is_always_equal{})
797       { }
798 
799       _GLIBCXX20_CONSTEXPR
800       vector(const vector& __x, const __type_identity_t<allocator_type>& __a)
801       : _Base(__a)
802       {
803           _M_initialize(__x.size());
804           _M_copy_aligned(__x.begin(), __x.end(), begin());
805       }
806 
807       _GLIBCXX20_CONSTEXPR
808       vector(initializer_list<bool> __l,
809                const allocator_type& __a = allocator_type())
810       : _Base(__a)
811       {
812           _M_initialize_range(__l.begin(), __l.end(),
813                                   random_access_iterator_tag());
814       }
815 #endif
816 
817 #if __cplusplus >= 201103L
818       template<typename _InputIterator,
819                  typename = std::_RequireInputIter<_InputIterator>>
820           _GLIBCXX20_CONSTEXPR
821           vector(_InputIterator __first, _InputIterator __last,
822                  const allocator_type& __a = allocator_type())
823           : _Base(__a)
824           {
825             _M_initialize_range(__first, __last,
826                                     std::__iterator_category(__first));
827           }
828 #else
829       template<typename _InputIterator>
830           vector(_InputIterator __first, _InputIterator __last,
831                  const allocator_type& __a = allocator_type())
832           : _Base(__a)
833           {
834             // Check whether it's an integral type. If so, it's not an iterator.
835             typedef typename std::__is_integer<_InputIterator>::__type _Integral;
836             _M_initialize_dispatch(__first, __last, _Integral());
837           }
838 #endif
839 
840       _GLIBCXX20_CONSTEXPR
841       ~vector() _GLIBCXX_NOEXCEPT { }
842 
843       _GLIBCXX20_CONSTEXPR
844       vector&
845       operator=(const vector& __x)
846       {
847           if (&__x == this)
848             return *this;
849 #if __cplusplus >= 201103L
850           if (_Bit_alloc_traits::_S_propagate_on_copy_assign())
851             {
852               if (this->_M_get_Bit_allocator() != __x._M_get_Bit_allocator())
853                 {
854                     this->_M_deallocate();
855                     std::__alloc_on_copy(_M_get_Bit_allocator(),
856                                              __x._M_get_Bit_allocator());
857                     _M_initialize(__x.size());
858                 }
859               else
860                 std::__alloc_on_copy(_M_get_Bit_allocator(),
861                                            __x._M_get_Bit_allocator());
862             }
863 #endif
864           if (__x.size() > capacity())
865             {
866               this->_M_deallocate();
867               _M_initialize(__x.size());
868             }
869           this->_M_impl._M_finish = _M_copy_aligned(__x.begin(), __x.end(),
870                                                               begin());
871           return *this;
872       }
873 
874 #if __cplusplus >= 201103L
875       _GLIBCXX20_CONSTEXPR
876       vector&
877       operator=(vector&& __x) noexcept(_Bit_alloc_traits::_S_nothrow_move())
878       {
879           if (_Bit_alloc_traits::_S_propagate_on_move_assign()
880               || this->_M_get_Bit_allocator() == __x._M_get_Bit_allocator())
881             {
882               this->_M_deallocate();
883               this->_M_move_data(std::move(__x));
884               std::__alloc_on_move(_M_get_Bit_allocator(),
885                                          __x._M_get_Bit_allocator());
886             }
887           else
888             {
889               if (__x.size() > capacity())
890                 {
891                     this->_M_deallocate();
892                     _M_initialize(__x.size());
893                 }
894               this->_M_impl._M_finish = _M_copy_aligned(__x.begin(), __x.end(),
895                                                                   begin());
896               __x.clear();
897             }
898           return *this;
899       }
900 
901       _GLIBCXX20_CONSTEXPR
902       vector&
903       operator=(initializer_list<bool> __l)
904       {
905           this->assign(__l.begin(), __l.end());
906           return *this;
907       }
908 #endif
909 
910       // assign(), a generalized assignment member function.  Two
911       // versions: one that takes a count, and one that takes a range.
912       // The range version is a member template, so we dispatch on whether
913       // or not the type is an integer.
914       _GLIBCXX20_CONSTEXPR
915       void
916       assign(size_type __n, const bool& __x)
917       { _M_fill_assign(__n, __x); }
918 
919 #if __cplusplus >= 201103L
920       template<typename _InputIterator,
921                  typename = std::_RequireInputIter<_InputIterator>>
922           _GLIBCXX20_CONSTEXPR
923           void
924           assign(_InputIterator __first, _InputIterator __last)
925           { _M_assign_aux(__first, __last, std::__iterator_category(__first)); }
926 #else
927       template<typename _InputIterator>
928           void
929           assign(_InputIterator __first, _InputIterator __last)
930           {
931             // Check whether it's an integral type. If so, it's not an iterator.
932             typedef typename std::__is_integer<_InputIterator>::__type _Integral;
933             _M_assign_dispatch(__first, __last, _Integral());
934           }
935 #endif
936 
937 #if __cplusplus >= 201103L
938       _GLIBCXX20_CONSTEXPR
939       void
940       assign(initializer_list<bool> __l)
941       { _M_assign_aux(__l.begin(), __l.end(), random_access_iterator_tag()); }
942 #endif
943 
944       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
945       iterator
946       begin() _GLIBCXX_NOEXCEPT
947       { return iterator(this->_M_impl._M_start._M_p, 0); }
948 
949       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
950       const_iterator
951       begin() const _GLIBCXX_NOEXCEPT
952       { return const_iterator(this->_M_impl._M_start._M_p, 0); }
953 
954       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
955       iterator
956       end() _GLIBCXX_NOEXCEPT
957       { return this->_M_impl._M_finish; }
958 
959       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
960       const_iterator
961       end() const _GLIBCXX_NOEXCEPT
962       { return this->_M_impl._M_finish; }
963 
964       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
965       reverse_iterator
966       rbegin() _GLIBCXX_NOEXCEPT
967       { return reverse_iterator(end()); }
968 
969       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
970       const_reverse_iterator
971       rbegin() const _GLIBCXX_NOEXCEPT
972       { return const_reverse_iterator(end()); }
973 
974       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
975       reverse_iterator
976       rend() _GLIBCXX_NOEXCEPT
977       { return reverse_iterator(begin()); }
978 
979       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
980       const_reverse_iterator
981       rend() const _GLIBCXX_NOEXCEPT
982       { return const_reverse_iterator(begin()); }
983 
984 #if __cplusplus >= 201103L
985       [[__nodiscard__]] _GLIBCXX20_CONSTEXPR
986       const_iterator
987       cbegin() const noexcept
988       { return const_iterator(this->_M_impl._M_start._M_p, 0); }
989 
990       [[__nodiscard__]] _GLIBCXX20_CONSTEXPR
991       const_iterator
992       cend() const noexcept
993       { return this->_M_impl._M_finish; }
994 
995       [[__nodiscard__]] _GLIBCXX20_CONSTEXPR
996       const_reverse_iterator
997       crbegin() const noexcept
998       { return const_reverse_iterator(end()); }
999 
1000       [[__nodiscard__]] _GLIBCXX20_CONSTEXPR
1001       const_reverse_iterator
1002       crend() const noexcept
1003       { return const_reverse_iterator(begin()); }
1004 #endif
1005 
1006       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1007       size_type
1008       size() const _GLIBCXX_NOEXCEPT
1009       { return size_type(end() - begin()); }
1010 
1011       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1012       size_type
1013       max_size() const _GLIBCXX_NOEXCEPT
1014       {
1015           const size_type __isize =
1016             __gnu_cxx::__numeric_traits<difference_type>::__max
1017             - int(_S_word_bit) + 1;
1018           const size_type __asize
1019             = _Bit_alloc_traits::max_size(_M_get_Bit_allocator());
1020           return (__asize <= __isize / int(_S_word_bit)
1021                     ? __asize * int(_S_word_bit) : __isize);
1022       }
1023 
1024       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1025       size_type
1026       capacity() const _GLIBCXX_NOEXCEPT
1027       { return size_type(const_iterator(this->_M_impl._M_end_addr(), 0)
1028                                - begin()); }
1029 
1030       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1031       bool
1032       empty() const _GLIBCXX_NOEXCEPT
1033       { return begin() == end(); }
1034 
1035       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1036       reference
1037       operator[](size_type __n)
1038       { return begin()[__n]; }
1039 
1040       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1041       const_reference
1042       operator[](size_type __n) const
1043       { return begin()[__n]; }
1044 
1045     protected:
1046       _GLIBCXX20_CONSTEXPR
1047       void
1048       _M_range_check(size_type __n) const
1049       {
1050           if (__n >= this->size())
1051             __throw_out_of_range_fmt(__N("vector<bool>::_M_range_check: __n "
1052                                                "(which is %zu) >= this->size() "
1053                                                "(which is %zu)"),
1054                                            __n, this->size());
1055       }
1056 
1057     public:
1058       _GLIBCXX20_CONSTEXPR
1059       reference
1060       at(size_type __n)
1061       {
1062           _M_range_check(__n);
1063           return (*this)[__n];
1064       }
1065 
1066       _GLIBCXX20_CONSTEXPR
1067       const_reference
1068       at(size_type __n) const
1069       {
1070           _M_range_check(__n);
1071           return (*this)[__n];
1072       }
1073 
1074       _GLIBCXX20_CONSTEXPR
1075       void
1076       reserve(size_type __n)
1077       {
1078           if (__n > max_size())
1079             __throw_length_error(__N("vector::reserve"));
1080           if (capacity() < __n)
1081             _M_reallocate(__n);
1082       }
1083 
1084       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1085       reference
1086       front()
1087       { return *begin(); }
1088 
1089       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1090       const_reference
1091       front() const
1092       { return *begin(); }
1093 
1094       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1095       reference
1096       back()
1097       { return *(end() - 1); }
1098 
1099       _GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
1100       const_reference
1101       back() const
1102       { return *(end() - 1); }
1103 
1104       _GLIBCXX20_CONSTEXPR
1105       void
1106       push_back(bool __x)
1107       {
1108           if (this->_M_impl._M_finish._M_p != this->_M_impl._M_end_addr())
1109             *this->_M_impl._M_finish++ = __x;
1110           else
1111             _M_insert_aux(end(), __x);
1112       }
1113 
1114       _GLIBCXX20_CONSTEXPR
1115       void
1116       swap(vector& __x) _GLIBCXX_NOEXCEPT
1117       {
1118 #if __cplusplus >= 201103L
1119           __glibcxx_assert(_Bit_alloc_traits::propagate_on_container_swap::value
1120                                || _M_get_Bit_allocator() == __x._M_get_Bit_allocator());
1121 #endif
1122           this->_M_impl._M_swap_data(__x._M_impl);
1123           _Bit_alloc_traits::_S_on_swap(_M_get_Bit_allocator(),
1124                                               __x._M_get_Bit_allocator());
1125       }
1126 
1127       // [23.2.5]/1, third-to-last entry in synopsis listing
1128       _GLIBCXX20_CONSTEXPR
1129       static void
1130       swap(reference __x, reference __y) _GLIBCXX_NOEXCEPT
1131       {
1132           bool __tmp = __x;
1133           __x = __y;
1134           __y = __tmp;
1135       }
1136 
1137       _GLIBCXX20_CONSTEXPR
1138       iterator
1139 #if __cplusplus >= 201103L
1140       insert(const_iterator __position, const bool& __x)
1141 #else
1142       insert(iterator __position, const bool& __x)
1143 #endif
1144       {
1145           const difference_type __n = __position - begin();
1146           if (this->_M_impl._M_finish._M_p != this->_M_impl._M_end_addr()
1147               && __position == end())
1148             *this->_M_impl._M_finish++ = __x;
1149           else
1150             _M_insert_aux(__position._M_const_cast(), __x);
1151           return begin() + __n;
1152       }
1153 
1154 #if _GLIBCXX_USE_DEPRECATED
1155       _GLIBCXX_DEPRECATED_SUGGEST("insert(position, false)")
1156       iterator
1157       insert(const_iterator __position)
1158       { return this->insert(__position._M_const_cast(), false); }
1159 #endif
1160 
1161 #if __cplusplus >= 201103L
1162       template<typename _InputIterator,
1163                  typename = std::_RequireInputIter<_InputIterator>>
1164           _GLIBCXX20_CONSTEXPR
1165           iterator
1166           insert(const_iterator __position,
1167                  _InputIterator __first, _InputIterator __last)
1168           {
1169             difference_type __offset = __position - cbegin();
1170             _M_insert_range(__position._M_const_cast(),
1171                                 __first, __last,
1172                                 std::__iterator_category(__first));
1173             return begin() + __offset;
1174           }
1175 #else
1176       template<typename _InputIterator>
1177           void
1178           insert(iterator __position,
1179                  _InputIterator __first, _InputIterator __last)
1180           {
1181             // Check whether it's an integral type. If so, it's not an iterator.
1182             typedef typename std::__is_integer<_InputIterator>::__type _Integral;
1183             _M_insert_dispatch(__position, __first, __last, _Integral());
1184           }
1185 #endif
1186 
1187 #if __cplusplus >= 201103L
1188       _GLIBCXX20_CONSTEXPR
1189       iterator
1190       insert(const_iterator __position, size_type __n, const bool& __x)
1191       {
1192           difference_type __offset = __position - cbegin();
1193           _M_fill_insert(__position._M_const_cast(), __n, __x);
1194           return begin() + __offset;
1195       }
1196 #else
1197       void
1198       insert(iterator __position, size_type __n, const bool& __x)
1199       { _M_fill_insert(__position, __n, __x); }
1200 #endif
1201 
1202 #if __cplusplus >= 201103L
1203       _GLIBCXX20_CONSTEXPR
1204       iterator
1205       insert(const_iterator __p, initializer_list<bool> __l)
1206       { return this->insert(__p, __l.begin(), __l.end()); }
1207 #endif
1208 
1209       _GLIBCXX20_CONSTEXPR
1210       void
1211       pop_back()
1212       { --this->_M_impl._M_finish; }
1213 
1214       _GLIBCXX20_CONSTEXPR
1215       iterator
1216 #if __cplusplus >= 201103L
1217       erase(const_iterator __position)
1218 #else
1219       erase(iterator __position)
1220 #endif
1221       { return _M_erase(__position._M_const_cast()); }
1222 
1223       _GLIBCXX20_CONSTEXPR
1224       iterator
1225 #if __cplusplus >= 201103L
1226       erase(const_iterator __first, const_iterator __last)
1227 #else
1228       erase(iterator __first, iterator __last)
1229 #endif
1230       { return _M_erase(__first._M_const_cast(), __last._M_const_cast()); }
1231 
1232       _GLIBCXX20_CONSTEXPR
1233       void
1234       resize(size_type __new_size, bool __x = bool())
1235       {
1236           if (__new_size < size())
1237             _M_erase_at_end(begin() + difference_type(__new_size));
1238           else
1239             insert(end(), __new_size - size(), __x);
1240       }
1241 
1242 #if __cplusplus >= 201103L
1243       _GLIBCXX20_CONSTEXPR
1244       void
1245       shrink_to_fit()
1246       { _M_shrink_to_fit(); }
1247 #endif
1248 
1249       _GLIBCXX20_CONSTEXPR
1250       void
1251       flip() _GLIBCXX_NOEXCEPT
1252       {
1253           _Bit_type * const __end = this->_M_impl._M_end_addr();
1254           for (_Bit_type * __p = this->_M_impl._M_start._M_p; __p != __end; ++__p)
1255             *__p = ~*__p;
1256       }
1257 
1258       _GLIBCXX20_CONSTEXPR
1259       void
1260       clear() _GLIBCXX_NOEXCEPT
1261       { _M_erase_at_end(begin()); }
1262 
1263 #if __cplusplus >= 201103L
1264       template<typename... _Args>
1265 #if __cplusplus > 201402L
1266           _GLIBCXX20_CONSTEXPR
1267           reference
1268 #else
1269           void
1270 #endif
1271           emplace_back(_Args&&... __args)
1272           {
1273             push_back(bool(__args...));
1274 #if __cplusplus > 201402L
1275             return back();
1276 #endif
1277           }
1278 
1279       template<typename... _Args>
1280           _GLIBCXX20_CONSTEXPR
1281           iterator
1282           emplace(const_iterator __pos, _Args&&... __args)
1283           { return insert(__pos, bool(__args...)); }
1284 #endif
1285 
1286     protected:
1287       // Precondition: __first._M_offset == 0 && __result._M_offset == 0.
1288       _GLIBCXX20_CONSTEXPR
1289       iterator
1290       _M_copy_aligned(const_iterator __first, const_iterator __last,
1291                           iterator __result)
1292       {
1293           _Bit_type* __q = std::copy(__first._M_p, __last._M_p, __result._M_p);
1294           return std::copy(const_iterator(__last._M_p, 0), __last,
1295                                iterator(__q, 0));
1296       }
1297 
1298       _GLIBCXX20_CONSTEXPR
1299       void
1300       _M_initialize(size_type __n)
1301       {
1302           if (__n)
1303             {
1304               _Bit_pointer __q = this->_M_allocate(__n);
1305               this->_M_impl._M_end_of_storage = __q + _S_nword(__n);
1306               iterator __start = iterator(std::__addressof(*__q), 0);
1307               this->_M_impl._M_start = __start;
1308               this->_M_impl._M_finish = __start + difference_type(__n);
1309             }
1310       }
1311 
1312       _GLIBCXX20_CONSTEXPR
1313       void
1314       _M_initialize_value(bool __x) _GLIBCXX_NOEXCEPT
1315       {
1316           if (_Bit_type* __p = this->_M_impl._M_start._M_p)
1317             __fill_bvector_n(__p, this->_M_impl._M_end_addr() - __p, __x);
1318       }
1319 
1320       _GLIBCXX20_CONSTEXPR
1321       void
1322       _M_reallocate(size_type __n);
1323 
1324 #if __cplusplus >= 201103L
1325       _GLIBCXX20_CONSTEXPR
1326       bool
1327       _M_shrink_to_fit();
1328 #endif
1329 
1330 #if __cplusplus < 201103L
1331       // _GLIBCXX_RESOLVE_LIB_DEFECTS
1332       // 438. Ambiguity in the "do the right thing" clause
1333       template<typename _Integer>
1334           void
1335           _M_initialize_dispatch(_Integer __n, _Integer __x, __true_type)
1336           {
1337             _M_initialize(static_cast<size_type>(__n));
1338             _M_initialize_value(__x);
1339           }
1340 
1341       template<typename _InputIterator>
1342           void
1343           _M_initialize_dispatch(_InputIterator __first, _InputIterator __last,
1344                                      __false_type)
1345           { _M_initialize_range(__first, __last,
1346                                     std::__iterator_category(__first)); }
1347 #endif
1348 
1349       template<typename _InputIterator>
1350           _GLIBCXX20_CONSTEXPR
1351           void
1352           _M_initialize_range(_InputIterator __first, _InputIterator __last,
1353                                   std::input_iterator_tag)
1354           {
1355             for (; __first != __last; ++__first)
1356               push_back(*__first);
1357           }
1358 
1359       template<typename _ForwardIterator>
1360           _GLIBCXX20_CONSTEXPR
1361           void
1362           _M_initialize_range(_ForwardIterator __first, _ForwardIterator __last,
1363                                   std::forward_iterator_tag)
1364           {
1365             const size_type __n = std::distance(__first, __last);
1366             _M_initialize(__n);
1367             std::copy(__first, __last, begin());
1368           }
1369 
1370 #if __cplusplus < 201103L
1371       // _GLIBCXX_RESOLVE_LIB_DEFECTS
1372       // 438. Ambiguity in the "do the right thing" clause
1373       template<typename _Integer>
1374           void
1375           _M_assign_dispatch(_Integer __n, _Integer __val, __true_type)
1376           { _M_fill_assign(__n, __val); }
1377 
1378       template<class _InputIterator>
1379           void
1380           _M_assign_dispatch(_InputIterator __first, _InputIterator __last,
1381                                  __false_type)
1382           { _M_assign_aux(__first, __last, std::__iterator_category(__first)); }
1383 #endif
1384 
1385       _GLIBCXX20_CONSTEXPR
1386       void
1387       _M_fill_assign(size_t __n, bool __x)
1388       {
1389           if (__n > size())
1390             {
1391               _M_initialize_value(__x);
1392               insert(end(), __n - size(), __x);
1393             }
1394           else
1395             {
1396               _M_erase_at_end(begin() + __n);
1397               _M_initialize_value(__x);
1398             }
1399       }
1400 
1401       template<typename _InputIterator>
1402           _GLIBCXX20_CONSTEXPR
1403           void
1404           _M_assign_aux(_InputIterator __first, _InputIterator __last,
1405                           std::input_iterator_tag)
1406           {
1407             iterator __cur = begin();
1408             for (; __first != __last && __cur != end(); ++__cur, (void)++__first)
1409               *__cur = *__first;
1410             if (__first == __last)
1411               _M_erase_at_end(__cur);
1412             else
1413               insert(end(), __first, __last);
1414           }
1415 
1416       template<typename _ForwardIterator>
1417           _GLIBCXX20_CONSTEXPR
1418           void
1419           _M_assign_aux(_ForwardIterator __first, _ForwardIterator __last,
1420                           std::forward_iterator_tag)
1421           {
1422             const size_type __len = std::distance(__first, __last);
1423             if (__len < size())
1424               _M_erase_at_end(std::copy(__first, __last, begin()));
1425             else
1426               {
1427                 _ForwardIterator __mid = __first;
1428                 std::advance(__mid, size());
1429                 std::copy(__first, __mid, begin());
1430                 insert(end(), __mid, __last);
1431               }
1432           }
1433 
1434 #if __cplusplus < 201103L
1435       // _GLIBCXX_RESOLVE_LIB_DEFECTS
1436       // 438. Ambiguity in the "do the right thing" clause
1437       template<typename _Integer>
1438           void
1439           _M_insert_dispatch(iterator __pos, _Integer __n, _Integer __x,
1440                                  __true_type)
1441           { _M_fill_insert(__pos, __n, __x); }
1442 
1443       template<typename _InputIterator>
1444           void
1445           _M_insert_dispatch(iterator __pos,
1446                                  _InputIterator __first, _InputIterator __last,
1447                                  __false_type)
1448           { _M_insert_range(__pos, __first, __last,
1449                                 std::__iterator_category(__first)); }
1450 #endif
1451 
1452       _GLIBCXX20_CONSTEXPR
1453       void
1454       _M_fill_insert(iterator __position, size_type __n, bool __x);
1455 
1456       template<typename _InputIterator>
1457           _GLIBCXX20_CONSTEXPR
1458           void
1459           _M_insert_range(iterator __pos, _InputIterator __first,
1460                               _InputIterator __last, std::input_iterator_tag)
1461           {
1462             for (; __first != __last; ++__first)
1463               {
1464                 __pos = insert(__pos, *__first);
1465                 ++__pos;
1466               }
1467           }
1468 
1469       template<typename _ForwardIterator>
1470           _GLIBCXX20_CONSTEXPR
1471           void
1472           _M_insert_range(iterator __position, _ForwardIterator __first,
1473                               _ForwardIterator __last, std::forward_iterator_tag);
1474 
1475       _GLIBCXX20_CONSTEXPR
1476       void
1477       _M_insert_aux(iterator __position, bool __x);
1478 
1479       _GLIBCXX20_CONSTEXPR
1480       size_type
1481       _M_check_len(size_type __n, const char* __s) const
1482       {
1483           if (max_size() - size() < __n)
1484             __throw_length_error(__N(__s));
1485 
1486           const size_type __len = size() + std::max(size(), __n);
1487           return (__len < size() || __len > max_size()) ? max_size() : __len;
1488       }
1489 
1490       _GLIBCXX20_CONSTEXPR
1491       void
1492       _M_erase_at_end(iterator __pos)
1493       { this->_M_impl._M_finish = __pos; }
1494 
1495       _GLIBCXX20_CONSTEXPR
1496       iterator
1497       _M_erase(iterator __pos);
1498 
1499       _GLIBCXX20_CONSTEXPR
1500       iterator
1501       _M_erase(iterator __first, iterator __last);
1502 
1503     protected:
1504       // _GLIBCXX_RESOLVE_LIB_DEFECTS
1505       // DR 464. Suggestion for new member functions in standard containers.
1506       // N.B. DR 464 says nothing about vector<bool> but we need something
1507       // here due to the using-declaration in __gnu_debug::vector.
1508       // vector class.
1509 #if __cplusplus >= 201103L
1510       void data() = delete;
1511 #else
1512       void data() { }
1513 #endif
1514     };
1515 
1516 _GLIBCXX_END_NAMESPACE_CONTAINER
1517 
1518   // Fill a partial word.
1519   _GLIBCXX20_CONSTEXPR
1520   inline void
1521   __fill_bvector(_Bit_type* __v, unsigned int __first, unsigned int __last,
1522                      bool __x) _GLIBCXX_NOEXCEPT
1523   {
1524     const _Bit_type __fmask = ~0ul << __first;
1525     const _Bit_type __lmask = ~0ul >> (_S_word_bit - __last);
1526     const _Bit_type __mask = __fmask & __lmask;
1527 
1528     if (__x)
1529       *__v |= __mask;
1530     else
1531       *__v &= ~__mask;
1532   }
1533 
1534   // Fill N full words, as if using memset, but usable in constant expressions.
1535   __attribute__((__nonnull__))
1536   _GLIBCXX20_CONSTEXPR
1537   inline void
1538   __fill_bvector_n(_Bit_type* __p, size_t __n, bool __x) _GLIBCXX_NOEXCEPT
1539   {
1540 #if __cpp_lib_is_constant_evaluated
1541     if (std::is_constant_evaluated())
1542     {
1543       for (size_t __i = 0; __i < __n; ++__i)
1544           __p[__i] = __x ? ~0ul : 0ul;
1545       return;
1546     }
1547 #endif
1548     __builtin_memset(__p, __x ? ~0 : 0, __n * sizeof(_Bit_type));
1549   }
1550 
1551 
1552   _GLIBCXX20_CONSTEXPR
1553   inline void
1554   __fill_a1(_GLIBCXX_STD_C::_Bit_iterator __first,
1555               _GLIBCXX_STD_C::_Bit_iterator __last, const bool& __x)
1556   {
1557     if (__first._M_p != __last._M_p)
1558       {
1559           _Bit_type* __first_p = __first._M_p;
1560           if (__first._M_offset != 0)
1561             __fill_bvector(__first_p++, __first._M_offset, _S_word_bit, __x);
1562 
1563           __fill_bvector_n(__first_p, __last._M_p - __first_p, __x);
1564 
1565           if (__last._M_offset != 0)
1566             __fill_bvector(__last._M_p, 0, __last._M_offset, __x);
1567       }
1568     else if (__first._M_offset != __last._M_offset)
1569       __fill_bvector(__first._M_p, __first._M_offset, __last._M_offset, __x);
1570   }
1571 
1572 #if __cplusplus >= 201103L
1573   // DR 1182.
1574   /// std::hash specialization for vector<bool>.
1575   template<typename _Alloc>
1576     struct hash<_GLIBCXX_STD_C::vector<bool, _Alloc>>
1577     : public __hash_base<size_t, _GLIBCXX_STD_C::vector<bool, _Alloc>>
1578     {
1579       size_t
1580       operator()(const _GLIBCXX_STD_C::vector<bool, _Alloc>&) const noexcept;
1581     };
1582 #endif // C++11
1583 
1584 _GLIBCXX_END_NAMESPACE_VERSION
1585 } // namespace std
1586 
1587 #endif
1588