xref: /freebsd/contrib/llvm-project/libcxx/include/deque (revision 36b606ae6aa4b24061096ba18582e0a08ccd5dba)
1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_DEQUE
11#define _LIBCPP_DEQUE
12
13/*
14    deque synopsis
15
16namespace std
17{
18
19template <class T, class Allocator = allocator<T> >
20class deque
21{
22public:
23    // types:
24    typedef T value_type;
25    typedef Allocator allocator_type;
26
27    typedef typename allocator_type::reference       reference;
28    typedef typename allocator_type::const_reference const_reference;
29    typedef implementation-defined                   iterator;
30    typedef implementation-defined                   const_iterator;
31    typedef typename allocator_type::size_type       size_type;
32    typedef typename allocator_type::difference_type difference_type;
33
34    typedef typename allocator_type::pointer         pointer;
35    typedef typename allocator_type::const_pointer   const_pointer;
36    typedef std::reverse_iterator<iterator>          reverse_iterator;
37    typedef std::reverse_iterator<const_iterator>    const_reverse_iterator;
38
39    // construct/copy/destroy:
40    deque() noexcept(is_nothrow_default_constructible<allocator_type>::value);
41    explicit deque(const allocator_type& a);
42    explicit deque(size_type n);
43    explicit deque(size_type n, const allocator_type& a); // C++14
44    deque(size_type n, const value_type& v);
45    deque(size_type n, const value_type& v, const allocator_type& a);
46    template <class InputIterator>
47        deque(InputIterator f, InputIterator l);
48    template <class InputIterator>
49        deque(InputIterator f, InputIterator l, const allocator_type& a);
50    template<container-compatible-range<T> R>
51        deque(from_range_t, R&& rg, const Allocator& = Allocator()); // C++23
52    deque(const deque& c);
53    deque(deque&& c)
54        noexcept(is_nothrow_move_constructible<allocator_type>::value);
55    deque(initializer_list<value_type> il, const Allocator& a = allocator_type());
56    deque(const deque& c, const allocator_type& a);
57    deque(deque&& c, const allocator_type& a);
58    ~deque();
59
60    deque& operator=(const deque& c);
61    deque& operator=(deque&& c)
62        noexcept(
63             allocator_type::propagate_on_container_move_assignment::value &&
64             is_nothrow_move_assignable<allocator_type>::value);
65    deque& operator=(initializer_list<value_type> il);
66
67    template <class InputIterator>
68        void assign(InputIterator f, InputIterator l);
69    template<container-compatible-range<T> R>
70      void assign_range(R&& rg); // C++23
71    void assign(size_type n, const value_type& v);
72    void assign(initializer_list<value_type> il);
73
74    allocator_type get_allocator() const noexcept;
75
76    // iterators:
77
78    iterator       begin() noexcept;
79    const_iterator begin() const noexcept;
80    iterator       end() noexcept;
81    const_iterator end() const noexcept;
82
83    reverse_iterator       rbegin() noexcept;
84    const_reverse_iterator rbegin() const noexcept;
85    reverse_iterator       rend() noexcept;
86    const_reverse_iterator rend() const noexcept;
87
88    const_iterator         cbegin() const noexcept;
89    const_iterator         cend() const noexcept;
90    const_reverse_iterator crbegin() const noexcept;
91    const_reverse_iterator crend() const noexcept;
92
93    // capacity:
94    size_type size() const noexcept;
95    size_type max_size() const noexcept;
96    void resize(size_type n);
97    void resize(size_type n, const value_type& v);
98    void shrink_to_fit();
99    bool empty() const noexcept;
100
101    // element access:
102    reference operator[](size_type i);
103    const_reference operator[](size_type i) const;
104    reference at(size_type i);
105    const_reference at(size_type i) const;
106    reference front();
107    const_reference front() const;
108    reference back();
109    const_reference back() const;
110
111    // modifiers:
112    void push_front(const value_type& v);
113    void push_front(value_type&& v);
114    template<container-compatible-range<T> R>
115      void prepend_range(R&& rg); // C++23
116    void push_back(const value_type& v);
117    void push_back(value_type&& v);
118    template<container-compatible-range<T> R>
119      void append_range(R&& rg); // C++23
120    template <class... Args> reference emplace_front(Args&&... args);  // reference in C++17
121    template <class... Args> reference emplace_back(Args&&... args);   // reference in C++17
122    template <class... Args> iterator emplace(const_iterator p, Args&&... args);
123    iterator insert(const_iterator p, const value_type& v);
124    iterator insert(const_iterator p, value_type&& v);
125    iterator insert(const_iterator p, size_type n, const value_type& v);
126    template <class InputIterator>
127        iterator insert(const_iterator p, InputIterator f, InputIterator l);
128    template<container-compatible-range<T> R>
129      iterator insert_range(const_iterator position, R&& rg); // C++23
130    iterator insert(const_iterator p, initializer_list<value_type> il);
131    void pop_front();
132    void pop_back();
133    iterator erase(const_iterator p);
134    iterator erase(const_iterator f, const_iterator l);
135    void swap(deque& c)
136        noexcept(allocator_traits<allocator_type>::is_always_equal::value);  // C++17
137    void clear() noexcept;
138};
139
140template <class InputIterator, class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
141   deque(InputIterator, InputIterator, Allocator = Allocator())
142   -> deque<typename iterator_traits<InputIterator>::value_type, Allocator>; // C++17
143
144template<ranges::input_range R, class Allocator = allocator<ranges::range_value_t<R>>>
145  deque(from_range_t, R&&, Allocator = Allocator())
146    -> deque<ranges::range_value_t<R>, Allocator>; // C++23
147
148template <class T, class Allocator>
149    bool operator==(const deque<T,Allocator>& x, const deque<T,Allocator>& y);
150template <class T, class Allocator>
151    bool operator< (const deque<T,Allocator>& x, const deque<T,Allocator>& y); // removed in C++20
152template <class T, class Allocator>
153    bool operator!=(const deque<T,Allocator>& x, const deque<T,Allocator>& y); // removed in C++20
154template <class T, class Allocator>
155    bool operator> (const deque<T,Allocator>& x, const deque<T,Allocator>& y); // removed in C++20
156template <class T, class Allocator>
157    bool operator>=(const deque<T,Allocator>& x, const deque<T,Allocator>& y); // removed in C++20
158template <class T, class Allocator>
159    bool operator<=(const deque<T,Allocator>& x, const deque<T,Allocator>& y); // removed in C++20
160template<class T, class Allocator>
161    synth-three-way-result<T> operator<=>(const deque<T, Allocator>& x,
162                                          const deque<T, Allocator>& y);       // since C++20
163
164// specialized algorithms:
165template <class T, class Allocator>
166    void swap(deque<T,Allocator>& x, deque<T,Allocator>& y)
167         noexcept(noexcept(x.swap(y)));
168
169template <class T, class Allocator, class U>
170    typename deque<T, Allocator>::size_type
171    erase(deque<T, Allocator>& c, const U& value);       // C++20
172template <class T, class Allocator, class Predicate>
173    typename deque<T, Allocator>::size_type
174    erase_if(deque<T, Allocator>& c, Predicate pred);    // C++20
175
176}  // std
177
178*/
179
180#include <__algorithm/copy.h>
181#include <__algorithm/copy_backward.h>
182#include <__algorithm/copy_n.h>
183#include <__algorithm/equal.h>
184#include <__algorithm/fill_n.h>
185#include <__algorithm/lexicographical_compare.h>
186#include <__algorithm/lexicographical_compare_three_way.h>
187#include <__algorithm/min.h>
188#include <__algorithm/remove.h>
189#include <__algorithm/remove_if.h>
190#include <__algorithm/unwrap_iter.h>
191#include <__assert>
192#include <__config>
193#include <__debug_utils/sanitizers.h>
194#include <__format/enable_insertable.h>
195#include <__fwd/deque.h>
196#include <__iterator/distance.h>
197#include <__iterator/iterator_traits.h>
198#include <__iterator/next.h>
199#include <__iterator/prev.h>
200#include <__iterator/reverse_iterator.h>
201#include <__iterator/segmented_iterator.h>
202#include <__memory/addressof.h>
203#include <__memory/allocator_destructor.h>
204#include <__memory/pointer_traits.h>
205#include <__memory/temp_value.h>
206#include <__memory/unique_ptr.h>
207#include <__memory_resource/polymorphic_allocator.h>
208#include <__ranges/access.h>
209#include <__ranges/concepts.h>
210#include <__ranges/container_compatible_range.h>
211#include <__ranges/from_range.h>
212#include <__ranges/size.h>
213#include <__split_buffer>
214#include <__type_traits/is_allocator.h>
215#include <__type_traits/is_convertible.h>
216#include <__type_traits/is_same.h>
217#include <__type_traits/is_swappable.h>
218#include <__type_traits/type_identity.h>
219#include <__utility/forward.h>
220#include <__utility/move.h>
221#include <__utility/pair.h>
222#include <__utility/swap.h>
223#include <limits>
224#include <stdexcept>
225#include <version>
226
227// standard-mandated includes
228
229// [iterator.range]
230#include <__iterator/access.h>
231#include <__iterator/data.h>
232#include <__iterator/empty.h>
233#include <__iterator/reverse_access.h>
234#include <__iterator/size.h>
235
236// [deque.syn]
237#include <compare>
238#include <initializer_list>
239
240#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
241#  pragma GCC system_header
242#endif
243
244_LIBCPP_PUSH_MACROS
245#include <__undef_macros>
246
247_LIBCPP_BEGIN_NAMESPACE_STD
248
249template <class _ValueType, class _DiffType>
250struct __deque_block_size {
251  static const _DiffType value = sizeof(_ValueType) < 256 ? 4096 / sizeof(_ValueType) : 16;
252};
253
254template <class _ValueType,
255          class _Pointer,
256          class _Reference,
257          class _MapPointer,
258          class _DiffType,
259          _DiffType _BS =
260#ifdef _LIBCPP_ABI_INCOMPLETE_TYPES_IN_DEQUE
261              // Keep template parameter to avoid changing all template declarations thoughout
262              // this file.
263          0
264#else
265              __deque_block_size<_ValueType, _DiffType>::value
266#endif
267          >
268class _LIBCPP_TEMPLATE_VIS __deque_iterator {
269  typedef _MapPointer __map_iterator;
270
271public:
272  typedef _Pointer pointer;
273  typedef _DiffType difference_type;
274
275private:
276  __map_iterator __m_iter_;
277  pointer __ptr_;
278
279  static const difference_type __block_size;
280
281public:
282  typedef _ValueType value_type;
283  typedef random_access_iterator_tag iterator_category;
284  typedef _Reference reference;
285
286  _LIBCPP_HIDE_FROM_ABI __deque_iterator() _NOEXCEPT
287#if _LIBCPP_STD_VER >= 14
288      : __m_iter_(nullptr),
289        __ptr_(nullptr)
290#endif
291  {
292  }
293
294  template <class _Pp, class _Rp, class _MP, __enable_if_t<is_convertible<_Pp, pointer>::value, int> = 0>
295  _LIBCPP_HIDE_FROM_ABI
296  __deque_iterator(const __deque_iterator<value_type, _Pp, _Rp, _MP, difference_type, _BS>& __it) _NOEXCEPT
297      : __m_iter_(__it.__m_iter_),
298        __ptr_(__it.__ptr_) {}
299
300  _LIBCPP_HIDE_FROM_ABI reference operator*() const { return *__ptr_; }
301  _LIBCPP_HIDE_FROM_ABI pointer operator->() const { return __ptr_; }
302
303  _LIBCPP_HIDE_FROM_ABI __deque_iterator& operator++() {
304    if (++__ptr_ - *__m_iter_ == __block_size) {
305      ++__m_iter_;
306      __ptr_ = *__m_iter_;
307    }
308    return *this;
309  }
310
311  _LIBCPP_HIDE_FROM_ABI __deque_iterator operator++(int) {
312    __deque_iterator __tmp = *this;
313    ++(*this);
314    return __tmp;
315  }
316
317  _LIBCPP_HIDE_FROM_ABI __deque_iterator& operator--() {
318    if (__ptr_ == *__m_iter_) {
319      --__m_iter_;
320      __ptr_ = *__m_iter_ + __block_size;
321    }
322    --__ptr_;
323    return *this;
324  }
325
326  _LIBCPP_HIDE_FROM_ABI __deque_iterator operator--(int) {
327    __deque_iterator __tmp = *this;
328    --(*this);
329    return __tmp;
330  }
331
332  _LIBCPP_HIDE_FROM_ABI __deque_iterator& operator+=(difference_type __n) {
333    if (__n != 0) {
334      __n += __ptr_ - *__m_iter_;
335      if (__n > 0) {
336        __m_iter_ += __n / __block_size;
337        __ptr_ = *__m_iter_ + __n % __block_size;
338      } else // (__n < 0)
339      {
340        difference_type __z = __block_size - 1 - __n;
341        __m_iter_ -= __z / __block_size;
342        __ptr_ = *__m_iter_ + (__block_size - 1 - __z % __block_size);
343      }
344    }
345    return *this;
346  }
347
348  _LIBCPP_HIDE_FROM_ABI __deque_iterator& operator-=(difference_type __n) { return *this += -__n; }
349
350  _LIBCPP_HIDE_FROM_ABI __deque_iterator operator+(difference_type __n) const {
351    __deque_iterator __t(*this);
352    __t += __n;
353    return __t;
354  }
355
356  _LIBCPP_HIDE_FROM_ABI __deque_iterator operator-(difference_type __n) const {
357    __deque_iterator __t(*this);
358    __t -= __n;
359    return __t;
360  }
361
362  _LIBCPP_HIDE_FROM_ABI friend __deque_iterator operator+(difference_type __n, const __deque_iterator& __it) {
363    return __it + __n;
364  }
365
366  _LIBCPP_HIDE_FROM_ABI friend difference_type operator-(const __deque_iterator& __x, const __deque_iterator& __y) {
367    if (__x != __y)
368      return (__x.__m_iter_ - __y.__m_iter_) * __block_size + (__x.__ptr_ - *__x.__m_iter_) -
369             (__y.__ptr_ - *__y.__m_iter_);
370    return 0;
371  }
372
373  _LIBCPP_HIDE_FROM_ABI reference operator[](difference_type __n) const { return *(*this + __n); }
374
375  _LIBCPP_HIDE_FROM_ABI friend bool operator==(const __deque_iterator& __x, const __deque_iterator& __y) {
376    return __x.__ptr_ == __y.__ptr_;
377  }
378
379#if _LIBCPP_STD_VER <= 17
380  _LIBCPP_HIDE_FROM_ABI friend bool operator!=(const __deque_iterator& __x, const __deque_iterator& __y) {
381    return !(__x == __y);
382  }
383#endif
384
385  // TODO(mordante) disable these overloads in the LLVM 20 release.
386  _LIBCPP_HIDE_FROM_ABI friend bool operator<(const __deque_iterator& __x, const __deque_iterator& __y) {
387    return __x.__m_iter_ < __y.__m_iter_ || (__x.__m_iter_ == __y.__m_iter_ && __x.__ptr_ < __y.__ptr_);
388  }
389
390  _LIBCPP_HIDE_FROM_ABI friend bool operator>(const __deque_iterator& __x, const __deque_iterator& __y) {
391    return __y < __x;
392  }
393
394  _LIBCPP_HIDE_FROM_ABI friend bool operator<=(const __deque_iterator& __x, const __deque_iterator& __y) {
395    return !(__y < __x);
396  }
397
398  _LIBCPP_HIDE_FROM_ABI friend bool operator>=(const __deque_iterator& __x, const __deque_iterator& __y) {
399    return !(__x < __y);
400  }
401
402#if _LIBCPP_STD_VER >= 20
403  _LIBCPP_HIDE_FROM_ABI friend strong_ordering operator<=>(const __deque_iterator& __x, const __deque_iterator& __y) {
404    if (__x.__m_iter_ < __y.__m_iter_)
405      return strong_ordering::less;
406
407    if (__x.__m_iter_ == __y.__m_iter_) {
408      if constexpr (three_way_comparable<pointer, strong_ordering>) {
409        return __x.__ptr_ <=> __y.__ptr_;
410      } else {
411        if (__x.__ptr_ < __y.__ptr_)
412          return strong_ordering::less;
413
414        if (__x.__ptr_ == __y.__ptr_)
415          return strong_ordering::equal;
416
417        return strong_ordering::greater;
418      }
419    }
420
421    return strong_ordering::greater;
422  }
423#endif // _LIBCPP_STD_VER >= 20
424
425private:
426  _LIBCPP_HIDE_FROM_ABI explicit __deque_iterator(__map_iterator __m, pointer __p) _NOEXCEPT
427      : __m_iter_(__m),
428        __ptr_(__p) {}
429
430  template <class _Tp, class _Ap>
431  friend class _LIBCPP_TEMPLATE_VIS deque;
432  template <class _Vp, class _Pp, class _Rp, class _MP, class _Dp, _Dp>
433  friend class _LIBCPP_TEMPLATE_VIS __deque_iterator;
434
435  template <class>
436  friend struct __segmented_iterator_traits;
437};
438
439template <class _ValueType, class _Pointer, class _Reference, class _MapPointer, class _DiffType, _DiffType _BlockSize>
440struct __segmented_iterator_traits<
441    __deque_iterator<_ValueType, _Pointer, _Reference, _MapPointer, _DiffType, _BlockSize> > {
442private:
443  using _Iterator = __deque_iterator<_ValueType, _Pointer, _Reference, _MapPointer, _DiffType, _BlockSize>;
444
445public:
446  using __is_segmented_iterator = true_type;
447  using __segment_iterator      = _MapPointer;
448  using __local_iterator        = _Pointer;
449
450  static _LIBCPP_HIDE_FROM_ABI __segment_iterator __segment(_Iterator __iter) { return __iter.__m_iter_; }
451  static _LIBCPP_HIDE_FROM_ABI __local_iterator __local(_Iterator __iter) { return __iter.__ptr_; }
452  static _LIBCPP_HIDE_FROM_ABI __local_iterator __begin(__segment_iterator __iter) { return *__iter; }
453
454  static _LIBCPP_HIDE_FROM_ABI __local_iterator __end(__segment_iterator __iter) {
455    return *__iter + _Iterator::__block_size;
456  }
457
458  static _LIBCPP_HIDE_FROM_ABI _Iterator __compose(__segment_iterator __segment, __local_iterator __local) {
459    if (__segment && __local == __end(__segment)) {
460      ++__segment;
461      return _Iterator(__segment, *__segment);
462    }
463    return _Iterator(__segment, __local);
464  }
465};
466
467template <class _ValueType, class _Pointer, class _Reference, class _MapPointer, class _DiffType, _DiffType _BlockSize>
468const _DiffType __deque_iterator<_ValueType, _Pointer, _Reference, _MapPointer, _DiffType, _BlockSize>::__block_size =
469    __deque_block_size<_ValueType, _DiffType>::value;
470
471template <class _Tp, class _Allocator /*= allocator<_Tp>*/>
472class _LIBCPP_TEMPLATE_VIS deque {
473public:
474  // types:
475
476  using value_type = _Tp;
477
478  using allocator_type = _Allocator;
479  using __alloc_traits = allocator_traits<allocator_type>;
480  static_assert(__check_valid_allocator<allocator_type>::value, "");
481  static_assert(is_same<typename allocator_type::value_type, value_type>::value,
482                "Allocator::value_type must be same type as value_type");
483
484  using size_type       = typename __alloc_traits::size_type;
485  using difference_type = typename __alloc_traits::difference_type;
486
487  using pointer       = typename __alloc_traits::pointer;
488  using const_pointer = typename __alloc_traits::const_pointer;
489
490  using __pointer_allocator       = __rebind_alloc<__alloc_traits, pointer>;
491  using __const_pointer_allocator = __rebind_alloc<__alloc_traits, const_pointer>;
492  using __map                     = __split_buffer<pointer, __pointer_allocator>;
493  using __map_alloc_traits        = allocator_traits<__pointer_allocator>;
494  using __map_pointer             = typename __map_alloc_traits::pointer;
495  using __map_const_pointer       = typename allocator_traits<__const_pointer_allocator>::const_pointer;
496  using __map_const_iterator      = typename __map::const_iterator;
497
498  using reference       = value_type&;
499  using const_reference = const value_type&;
500
501  using iterator = __deque_iterator<value_type, pointer, reference, __map_pointer, difference_type>;
502  using const_iterator =
503      __deque_iterator<value_type, const_pointer, const_reference, __map_const_pointer, difference_type>;
504  using reverse_iterator       = std::reverse_iterator<iterator>;
505  using const_reverse_iterator = std::reverse_iterator<const_iterator>;
506
507  // A deque contains the following members which may be trivially relocatable:
508  // - __map: is a `__split_buffer`, see `__split_buffer` for more information on when it is trivially relocatable
509  // - size_type: is always trivially relocatable, since it is required to be an integral type
510  // - allocator_type: may not be trivially relocatable, so it's checked
511  // None of these are referencing the `deque` itself, so if all of them are trivially relocatable, `deque` is too.
512  using __trivially_relocatable = __conditional_t<
513      __libcpp_is_trivially_relocatable<__map>::value && __libcpp_is_trivially_relocatable<allocator_type>::value,
514      deque,
515      void>;
516
517  static_assert(is_nothrow_default_constructible<allocator_type>::value ==
518                    is_nothrow_default_constructible<__pointer_allocator>::value,
519                "rebinding an allocator should not change exception guarantees");
520  static_assert(is_nothrow_move_constructible<allocator_type>::value ==
521                    is_nothrow_move_constructible<typename __map::allocator_type>::value,
522                "rebinding an allocator should not change exception guarantees");
523
524private:
525  struct __deque_block_range {
526    explicit _LIBCPP_HIDE_FROM_ABI __deque_block_range(pointer __b, pointer __e) _NOEXCEPT
527        : __begin_(__b),
528          __end_(__e) {}
529    const pointer __begin_;
530    const pointer __end_;
531  };
532
533  struct __deque_range {
534    iterator __pos_;
535    const iterator __end_;
536
537    _LIBCPP_HIDE_FROM_ABI __deque_range(iterator __pos, iterator __e) _NOEXCEPT : __pos_(__pos), __end_(__e) {}
538
539    explicit _LIBCPP_HIDE_FROM_ABI operator bool() const _NOEXCEPT { return __pos_ != __end_; }
540
541    _LIBCPP_HIDE_FROM_ABI __deque_range begin() const { return *this; }
542
543    _LIBCPP_HIDE_FROM_ABI __deque_range end() const { return __deque_range(__end_, __end_); }
544    _LIBCPP_HIDE_FROM_ABI __deque_block_range operator*() const _NOEXCEPT {
545      if (__pos_.__m_iter_ == __end_.__m_iter_) {
546        return __deque_block_range(__pos_.__ptr_, __end_.__ptr_);
547      }
548      return __deque_block_range(__pos_.__ptr_, *__pos_.__m_iter_ + __block_size);
549    }
550
551    _LIBCPP_HIDE_FROM_ABI __deque_range& operator++() _NOEXCEPT {
552      if (__pos_.__m_iter_ == __end_.__m_iter_) {
553        __pos_ = __end_;
554      } else {
555        ++__pos_.__m_iter_;
556        __pos_.__ptr_ = *__pos_.__m_iter_;
557      }
558      return *this;
559    }
560
561    _LIBCPP_HIDE_FROM_ABI friend bool operator==(__deque_range const& __lhs, __deque_range const& __rhs) {
562      return __lhs.__pos_ == __rhs.__pos_;
563    }
564    _LIBCPP_HIDE_FROM_ABI friend bool operator!=(__deque_range const& __lhs, __deque_range const& __rhs) {
565      return !(__lhs == __rhs);
566    }
567  };
568
569  struct _ConstructTransaction {
570    _LIBCPP_HIDE_FROM_ABI _ConstructTransaction(deque* __db, __deque_block_range& __r)
571        : __pos_(__r.__begin_), __end_(__r.__end_), __begin_(__r.__begin_), __base_(__db) {}
572
573    _LIBCPP_HIDE_FROM_ABI ~_ConstructTransaction() { __base_->__size() += (__pos_ - __begin_); }
574
575    pointer __pos_;
576    const pointer __end_;
577
578  private:
579    const pointer __begin_;
580    deque* const __base_;
581  };
582
583  static const difference_type __block_size;
584
585  __map __map_;
586  size_type __start_;
587  __compressed_pair<size_type, allocator_type> __size_;
588
589public:
590  // construct/copy/destroy:
591  _LIBCPP_HIDE_FROM_ABI deque() _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
592      : __start_(0), __size_(0, __default_init_tag()) {
593    __annotate_new(0);
594  }
595
596  _LIBCPP_HIDE_FROM_ABI ~deque() {
597    clear();
598    __annotate_delete();
599    typename __map::iterator __i = __map_.begin();
600    typename __map::iterator __e = __map_.end();
601    for (; __i != __e; ++__i)
602      __alloc_traits::deallocate(__alloc(), *__i, __block_size);
603  }
604
605  _LIBCPP_HIDE_FROM_ABI explicit deque(const allocator_type& __a)
606      : __map_(__pointer_allocator(__a)), __start_(0), __size_(0, __a) {
607    __annotate_new(0);
608  }
609
610  explicit _LIBCPP_HIDE_FROM_ABI deque(size_type __n);
611#if _LIBCPP_STD_VER >= 14
612  explicit _LIBCPP_HIDE_FROM_ABI deque(size_type __n, const _Allocator& __a);
613#endif
614  _LIBCPP_HIDE_FROM_ABI deque(size_type __n, const value_type& __v);
615
616  template <__enable_if_t<__is_allocator<_Allocator>::value, int> = 0>
617  _LIBCPP_HIDE_FROM_ABI deque(size_type __n, const value_type& __v, const allocator_type& __a)
618      : __map_(__pointer_allocator(__a)), __start_(0), __size_(0, __a) {
619    __annotate_new(0);
620    if (__n > 0)
621      __append(__n, __v);
622  }
623
624  template <class _InputIter, __enable_if_t<__has_input_iterator_category<_InputIter>::value, int> = 0>
625  _LIBCPP_HIDE_FROM_ABI deque(_InputIter __f, _InputIter __l);
626  template <class _InputIter, __enable_if_t<__has_input_iterator_category<_InputIter>::value, int> = 0>
627  _LIBCPP_HIDE_FROM_ABI deque(_InputIter __f, _InputIter __l, const allocator_type& __a);
628
629#if _LIBCPP_STD_VER >= 23
630  template <_ContainerCompatibleRange<_Tp> _Range>
631  _LIBCPP_HIDE_FROM_ABI deque(from_range_t, _Range&& __range, const allocator_type& __a = allocator_type())
632      : __map_(__pointer_allocator(__a)), __start_(0), __size_(0, __a) {
633    if constexpr (ranges::forward_range<_Range> || ranges::sized_range<_Range>) {
634      __append_with_size(ranges::begin(__range), ranges::distance(__range));
635
636    } else {
637      for (auto&& __e : __range) {
638        emplace_back(std::forward<decltype(__e)>(__e));
639      }
640    }
641  }
642#endif
643
644  _LIBCPP_HIDE_FROM_ABI deque(const deque& __c);
645  _LIBCPP_HIDE_FROM_ABI deque(const deque& __c, const __type_identity_t<allocator_type>& __a);
646
647  _LIBCPP_HIDE_FROM_ABI deque& operator=(const deque& __c);
648
649#ifndef _LIBCPP_CXX03_LANG
650  _LIBCPP_HIDE_FROM_ABI deque(initializer_list<value_type> __il);
651  _LIBCPP_HIDE_FROM_ABI deque(initializer_list<value_type> __il, const allocator_type& __a);
652
653  _LIBCPP_HIDE_FROM_ABI deque& operator=(initializer_list<value_type> __il) {
654    assign(__il);
655    return *this;
656  }
657
658  _LIBCPP_HIDE_FROM_ABI deque(deque&& __c) noexcept(is_nothrow_move_constructible<allocator_type>::value);
659  _LIBCPP_HIDE_FROM_ABI deque(deque&& __c, const __type_identity_t<allocator_type>& __a);
660  _LIBCPP_HIDE_FROM_ABI deque&
661  operator=(deque&& __c) noexcept(__alloc_traits::propagate_on_container_move_assignment::value &&
662                                  is_nothrow_move_assignable<allocator_type>::value);
663
664  _LIBCPP_HIDE_FROM_ABI void assign(initializer_list<value_type> __il) { assign(__il.begin(), __il.end()); }
665#endif // _LIBCPP_CXX03_LANG
666
667  template <class _InputIter,
668            __enable_if_t<__has_input_iterator_category<_InputIter>::value &&
669                              !__has_random_access_iterator_category<_InputIter>::value,
670                          int> = 0>
671  _LIBCPP_HIDE_FROM_ABI void assign(_InputIter __f, _InputIter __l);
672  template <class _RAIter, __enable_if_t<__has_random_access_iterator_category<_RAIter>::value, int> = 0>
673  _LIBCPP_HIDE_FROM_ABI void assign(_RAIter __f, _RAIter __l);
674
675#if _LIBCPP_STD_VER >= 23
676  template <_ContainerCompatibleRange<_Tp> _Range>
677  _LIBCPP_HIDE_FROM_ABI void assign_range(_Range&& __range) {
678    if constexpr (ranges::random_access_range<_Range>) {
679      auto __n = static_cast<size_type>(ranges::distance(__range));
680      __assign_with_size_random_access(ranges::begin(__range), __n);
681
682    } else if constexpr (ranges::forward_range<_Range> || ranges::sized_range<_Range>) {
683      auto __n = static_cast<size_type>(ranges::distance(__range));
684      __assign_with_size(ranges::begin(__range), __n);
685
686    } else {
687      __assign_with_sentinel(ranges::begin(__range), ranges::end(__range));
688    }
689  }
690#endif
691
692  _LIBCPP_HIDE_FROM_ABI void assign(size_type __n, const value_type& __v);
693
694  _LIBCPP_HIDE_FROM_ABI allocator_type get_allocator() const _NOEXCEPT;
695  _LIBCPP_HIDE_FROM_ABI allocator_type& __alloc() _NOEXCEPT { return __size_.second(); }
696  _LIBCPP_HIDE_FROM_ABI const allocator_type& __alloc() const _NOEXCEPT { return __size_.second(); }
697
698  // iterators:
699
700  _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT {
701    __map_pointer __mp = __map_.begin() + __start_ / __block_size;
702    return iterator(__mp, __map_.empty() ? 0 : *__mp + __start_ % __block_size);
703  }
704
705  _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT {
706    __map_const_pointer __mp = static_cast<__map_const_pointer>(__map_.begin() + __start_ / __block_size);
707    return const_iterator(__mp, __map_.empty() ? 0 : *__mp + __start_ % __block_size);
708  }
709
710  _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT {
711    size_type __p      = size() + __start_;
712    __map_pointer __mp = __map_.begin() + __p / __block_size;
713    return iterator(__mp, __map_.empty() ? 0 : *__mp + __p % __block_size);
714  }
715
716  _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT {
717    size_type __p            = size() + __start_;
718    __map_const_pointer __mp = static_cast<__map_const_pointer>(__map_.begin() + __p / __block_size);
719    return const_iterator(__mp, __map_.empty() ? 0 : *__mp + __p % __block_size);
720  }
721
722  _LIBCPP_HIDE_FROM_ABI reverse_iterator rbegin() _NOEXCEPT { return reverse_iterator(end()); }
723  _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rbegin() const _NOEXCEPT { return const_reverse_iterator(end()); }
724  _LIBCPP_HIDE_FROM_ABI reverse_iterator rend() _NOEXCEPT { return reverse_iterator(begin()); }
725  _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rend() const _NOEXCEPT { return const_reverse_iterator(begin()); }
726
727  _LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT { return begin(); }
728  _LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT { return end(); }
729  _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crbegin() const _NOEXCEPT { return const_reverse_iterator(end()); }
730  _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crend() const _NOEXCEPT { return const_reverse_iterator(begin()); }
731
732  // capacity:
733  _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __size(); }
734
735  _LIBCPP_HIDE_FROM_ABI size_type& __size() _NOEXCEPT { return __size_.first(); }
736  _LIBCPP_HIDE_FROM_ABI const size_type& __size() const _NOEXCEPT { return __size_.first(); }
737
738  _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT {
739    return std::min<size_type>(__alloc_traits::max_size(__alloc()), numeric_limits<difference_type>::max());
740  }
741  _LIBCPP_HIDE_FROM_ABI void resize(size_type __n);
742  _LIBCPP_HIDE_FROM_ABI void resize(size_type __n, const value_type& __v);
743  _LIBCPP_HIDE_FROM_ABI void shrink_to_fit() _NOEXCEPT;
744  _LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return size() == 0; }
745
746  // element access:
747  _LIBCPP_HIDE_FROM_ABI reference operator[](size_type __i) _NOEXCEPT;
748  _LIBCPP_HIDE_FROM_ABI const_reference operator[](size_type __i) const _NOEXCEPT;
749  _LIBCPP_HIDE_FROM_ABI reference at(size_type __i);
750  _LIBCPP_HIDE_FROM_ABI const_reference at(size_type __i) const;
751  _LIBCPP_HIDE_FROM_ABI reference front() _NOEXCEPT;
752  _LIBCPP_HIDE_FROM_ABI const_reference front() const _NOEXCEPT;
753  _LIBCPP_HIDE_FROM_ABI reference back() _NOEXCEPT;
754  _LIBCPP_HIDE_FROM_ABI const_reference back() const _NOEXCEPT;
755
756  // 23.2.2.3 modifiers:
757  _LIBCPP_HIDE_FROM_ABI void push_front(const value_type& __v);
758  _LIBCPP_HIDE_FROM_ABI void push_back(const value_type& __v);
759#ifndef _LIBCPP_CXX03_LANG
760#  if _LIBCPP_STD_VER >= 17
761  template <class... _Args>
762  _LIBCPP_HIDE_FROM_ABI reference emplace_front(_Args&&... __args);
763  template <class... _Args>
764  _LIBCPP_HIDE_FROM_ABI reference emplace_back(_Args&&... __args);
765#  else
766  template <class... _Args>
767  _LIBCPP_HIDE_FROM_ABI void emplace_front(_Args&&... __args);
768  template <class... _Args>
769  _LIBCPP_HIDE_FROM_ABI void emplace_back(_Args&&... __args);
770#  endif
771  template <class... _Args>
772  _LIBCPP_HIDE_FROM_ABI iterator emplace(const_iterator __p, _Args&&... __args);
773
774  _LIBCPP_HIDE_FROM_ABI void push_front(value_type&& __v);
775  _LIBCPP_HIDE_FROM_ABI void push_back(value_type&& __v);
776
777#  if _LIBCPP_STD_VER >= 23
778  template <_ContainerCompatibleRange<_Tp> _Range>
779  _LIBCPP_HIDE_FROM_ABI void prepend_range(_Range&& __range) {
780    insert_range(begin(), std::forward<_Range>(__range));
781  }
782
783  template <_ContainerCompatibleRange<_Tp> _Range>
784  _LIBCPP_HIDE_FROM_ABI void append_range(_Range&& __range) {
785    insert_range(end(), std::forward<_Range>(__range));
786  }
787#  endif
788
789  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, value_type&& __v);
790
791  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, initializer_list<value_type> __il) {
792    return insert(__p, __il.begin(), __il.end());
793  }
794#endif // _LIBCPP_CXX03_LANG
795  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, const value_type& __v);
796  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, size_type __n, const value_type& __v);
797  template <class _InputIter, __enable_if_t<__has_exactly_input_iterator_category<_InputIter>::value, int> = 0>
798  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, _InputIter __f, _InputIter __l);
799  template <class _ForwardIterator,
800            __enable_if_t<__has_exactly_forward_iterator_category<_ForwardIterator>::value, int> = 0>
801  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, _ForwardIterator __f, _ForwardIterator __l);
802  template <class _BiIter, __enable_if_t<__has_bidirectional_iterator_category<_BiIter>::value, int> = 0>
803  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, _BiIter __f, _BiIter __l);
804
805#if _LIBCPP_STD_VER >= 23
806  template <_ContainerCompatibleRange<_Tp> _Range>
807  _LIBCPP_HIDE_FROM_ABI iterator insert_range(const_iterator __position, _Range&& __range) {
808    if constexpr (ranges::bidirectional_range<_Range>) {
809      auto __n = static_cast<size_type>(ranges::distance(__range));
810      return __insert_bidirectional(__position, ranges::begin(__range), ranges::end(__range), __n);
811
812    } else if constexpr (ranges::forward_range<_Range> || ranges::sized_range<_Range>) {
813      auto __n = static_cast<size_type>(ranges::distance(__range));
814      return __insert_with_size(__position, ranges::begin(__range), __n);
815
816    } else {
817      return __insert_with_sentinel(__position, ranges::begin(__range), ranges::end(__range));
818    }
819  }
820#endif
821
822  _LIBCPP_HIDE_FROM_ABI void pop_front();
823  _LIBCPP_HIDE_FROM_ABI void pop_back();
824  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __p);
825  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __f, const_iterator __l);
826
827  _LIBCPP_HIDE_FROM_ABI void swap(deque& __c)
828#if _LIBCPP_STD_VER >= 14
829      _NOEXCEPT;
830#else
831      _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value || __is_nothrow_swappable_v<allocator_type>);
832#endif
833  _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT;
834
835  _LIBCPP_HIDE_FROM_ABI bool __invariants() const {
836    if (!__map_.__invariants())
837      return false;
838    if (__map_.size() >= size_type(-1) / __block_size)
839      return false;
840    for (__map_const_iterator __i = __map_.begin(), __e = __map_.end(); __i != __e; ++__i)
841      if (*__i == nullptr)
842        return false;
843    if (__map_.size() != 0) {
844      if (size() >= __map_.size() * __block_size)
845        return false;
846      if (__start_ >= __map_.size() * __block_size - size())
847        return false;
848    } else {
849      if (size() != 0)
850        return false;
851      if (__start_ != 0)
852        return false;
853    }
854    return true;
855  }
856
857  _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(deque& __c)
858      _NOEXCEPT_(!__alloc_traits::propagate_on_container_move_assignment::value ||
859                 is_nothrow_move_assignable<allocator_type>::value) {
860    __move_assign_alloc(__c, integral_constant<bool, __alloc_traits::propagate_on_container_move_assignment::value>());
861  }
862
863  _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(deque& __c, true_type)
864      _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value) {
865    __alloc() = std::move(__c.__alloc());
866  }
867
868  _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(deque&, false_type) _NOEXCEPT {}
869
870  _LIBCPP_HIDE_FROM_ABI void __move_assign(deque& __c)
871      _NOEXCEPT_(__alloc_traits::propagate_on_container_move_assignment::value&&
872                     is_nothrow_move_assignable<allocator_type>::value) {
873    __map_   = std::move(__c.__map_);
874    __start_ = __c.__start_;
875    __size() = __c.size();
876    __move_assign_alloc(__c);
877    __c.__start_ = __c.__size() = 0;
878  }
879
880  _LIBCPP_HIDE_FROM_ABI static size_type __recommend_blocks(size_type __n) {
881    return __n / __block_size + (__n % __block_size != 0);
882  }
883  _LIBCPP_HIDE_FROM_ABI size_type __capacity() const {
884    return __map_.size() == 0 ? 0 : __map_.size() * __block_size - 1;
885  }
886  _LIBCPP_HIDE_FROM_ABI size_type __block_count() const { return __map_.size(); }
887
888  _LIBCPP_HIDE_FROM_ABI size_type __front_spare() const { return __start_; }
889  _LIBCPP_HIDE_FROM_ABI size_type __front_spare_blocks() const { return __front_spare() / __block_size; }
890  _LIBCPP_HIDE_FROM_ABI size_type __back_spare() const { return __capacity() - (__start_ + size()); }
891  _LIBCPP_HIDE_FROM_ABI size_type __back_spare_blocks() const { return __back_spare() / __block_size; }
892
893private:
894  enum __asan_annotation_type { __asan_unposion, __asan_poison };
895
896  enum __asan_annotation_place {
897    __asan_front_moved,
898    __asan_back_moved,
899  };
900
901  _LIBCPP_HIDE_FROM_ABI void __annotate_from_to(
902      size_type __beg,
903      size_type __end,
904      __asan_annotation_type __annotation_type,
905      __asan_annotation_place __place) const _NOEXCEPT {
906    (void)__beg;
907    (void)__end;
908    (void)__annotation_type;
909    (void)__place;
910#ifndef _LIBCPP_HAS_NO_ASAN
911    // __beg - index of the first item to annotate
912    // __end - index behind the last item to annotate (so last item + 1)
913    // __annotation_type - __asan_unposion or __asan_poison
914    // __place - __asan_front_moved or __asan_back_moved
915    // Note: All indexes in __map_
916    if (__beg == __end)
917      return;
918    // __annotations_beg_map - first chunk which annotations we want to modify
919    // __annotations_end_map - last chunk which annotations we want to modify
920    // NOTE: if __end % __block_size == 0, __annotations_end_map points at the next block, which may not exist
921    __map_const_iterator __annotations_beg_map = __map_.begin() + __beg / __block_size;
922    __map_const_iterator __annotations_end_map = __map_.begin() + __end / __block_size;
923
924    bool const __poisoning = __annotation_type == __asan_poison;
925    // __old_c_beg_index - index of the first element in old container
926    // __old_c_end_index - index of the end of old container (last + 1)
927    // Note: may be outside the area we are annotating
928    size_t __old_c_beg_index = (__poisoning && __place == __asan_front_moved) ? __beg : __start_;
929    size_t __old_c_end_index = (__poisoning && __place == __asan_back_moved) ? __end : __start_ + size();
930    bool const __front       = __place == __asan_front_moved;
931
932    if (__poisoning && empty()) {
933      // Special case: we shouldn't trust __start_
934      __old_c_beg_index = __beg;
935      __old_c_end_index = __end;
936    }
937    // __old_c_beg_map - memory block (chunk) with first element
938    // __old_c_end_map - memory block (chunk) with end of old container
939    // Note: if __old_c_end_index % __block_size == 0, __old_c_end_map points at the next block,
940    // which may not exist
941    __map_const_iterator __old_c_beg_map = __map_.begin() + __old_c_beg_index / __block_size;
942    __map_const_iterator __old_c_end_map = __map_.begin() + __old_c_end_index / __block_size;
943
944    // One edge (front/end) of the container was moved and one was not modified.
945    // __new_edge_index - index of new edge
946    // __new_edge_map    - memory block (chunk) with new edge, it always equals to
947    //                    __annotations_beg_map or __annotations_end_map
948    // __old_edge_map    - memory block (chunk) with old edge, it always equals to
949    //                    __old_c_beg_map or __old_c_end_map
950    size_t __new_edge_index             = (__poisoning ^ __front) ? __beg : __end;
951    __map_const_iterator __new_edge_map = __map_.begin() + __new_edge_index / __block_size;
952    __map_const_iterator __old_edge_map = __front ? __old_c_end_map : __old_c_beg_map;
953
954    // We iterate over map pointers (chunks) and fully poison all memory blocks between the first and the last.
955    // First and last chunk may be partially poisoned.
956    // __annotate_end_map may point at not existing chunk, therefore we have to have a check for it.
957    for (__map_const_iterator __map_it = __annotations_beg_map; __map_it <= __annotations_end_map; ++__map_it) {
958      if (__map_it == __annotations_end_map && __end % __block_size == 0)
959        // Chunk may not exist, but nothing to do here anyway
960        break;
961
962      // The beginning and the end of the current memory block
963      const void* __mem_beg = std::__to_address(*__map_it);
964      const void* __mem_end = std::__to_address(*__map_it + __block_size);
965
966      // The beginning of memory-in-use in the memory block before container modification
967      const void* __old_beg =
968          (__map_it == __old_c_beg_map) ? std::__to_address(*__map_it + (__old_c_beg_index % __block_size)) : __mem_beg;
969
970      // The end of memory-in-use in the memory block before container modification
971      const void* __old_end;
972      if (__map_it < __old_c_beg_map || __map_it > __old_c_end_map || (!__poisoning && empty()))
973        __old_end = __old_beg;
974      else
975        __old_end = (__map_it == __old_c_end_map)
976                      ? std::__to_address(*__map_it + (__old_c_end_index % __block_size))
977                      : __mem_end;
978
979      // New edge of the container in current memory block
980      // If the edge is in a different chunk it points on corresponding end of the memory block
981      const void* __new_edge;
982      if (__map_it == __new_edge_map)
983        __new_edge = std::__to_address(*__map_it + (__new_edge_index % __block_size));
984      else
985        __new_edge = (__poisoning ^ __front) ? __mem_beg : __mem_end;
986
987      // Not modified edge of the container
988      // If the edge is in a different chunk it points on corresponding end of the memory block
989      const void* __old_edge;
990      if (__map_it == __old_edge_map)
991        __old_edge = __front ? __old_end : __old_beg;
992      else
993        __old_edge = __front ? __mem_end : __mem_beg;
994
995      // __new_beg - the beginning of memory-in-use in the memory block after container modification
996      // __new_end - the end of memory-in-use in the memory block after container modification
997      const void* __new_beg = __front ? __new_edge : __old_edge;
998      const void* __new_end = __front ? __old_edge : __new_edge;
999
1000      std::__annotate_double_ended_contiguous_container<_Allocator>(
1001          __mem_beg, __mem_end, __old_beg, __old_end, __new_beg, __new_end);
1002    }
1003#endif // !_LIBCPP_HAS_NO_ASAN
1004  }
1005
1006  _LIBCPP_HIDE_FROM_ABI void __annotate_new(size_type __current_size) const _NOEXCEPT {
1007    (void)__current_size;
1008#ifndef _LIBCPP_HAS_NO_ASAN
1009    if (__current_size == 0)
1010      __annotate_from_to(0, __map_.size() * __block_size, __asan_poison, __asan_back_moved);
1011    else {
1012      __annotate_from_to(0, __start_, __asan_poison, __asan_front_moved);
1013      __annotate_from_to(__start_ + __current_size, __map_.size() * __block_size, __asan_poison, __asan_back_moved);
1014    }
1015#endif
1016  }
1017
1018  _LIBCPP_HIDE_FROM_ABI void __annotate_delete() const _NOEXCEPT {
1019#ifndef _LIBCPP_HAS_NO_ASAN
1020    if (empty()) {
1021      for (size_t __i = 0; __i < __map_.size(); ++__i) {
1022        __annotate_whole_block(__i, __asan_unposion);
1023      }
1024    } else {
1025      __annotate_from_to(0, __start_, __asan_unposion, __asan_front_moved);
1026      __annotate_from_to(__start_ + size(), __map_.size() * __block_size, __asan_unposion, __asan_back_moved);
1027    }
1028#endif
1029  }
1030
1031  _LIBCPP_HIDE_FROM_ABI void __annotate_increase_front(size_type __n) const _NOEXCEPT {
1032    (void)__n;
1033#ifndef _LIBCPP_HAS_NO_ASAN
1034    __annotate_from_to(__start_ - __n, __start_, __asan_unposion, __asan_front_moved);
1035#endif
1036  }
1037
1038  _LIBCPP_HIDE_FROM_ABI void __annotate_increase_back(size_type __n) const _NOEXCEPT {
1039    (void)__n;
1040#ifndef _LIBCPP_HAS_NO_ASAN
1041    __annotate_from_to(__start_ + size(), __start_ + size() + __n, __asan_unposion, __asan_back_moved);
1042#endif
1043  }
1044
1045  _LIBCPP_HIDE_FROM_ABI void __annotate_shrink_front(size_type __old_size, size_type __old_start) const _NOEXCEPT {
1046    (void)__old_size;
1047    (void)__old_start;
1048#ifndef _LIBCPP_HAS_NO_ASAN
1049    __annotate_from_to(__old_start, __old_start + (__old_size - size()), __asan_poison, __asan_front_moved);
1050#endif
1051  }
1052
1053  _LIBCPP_HIDE_FROM_ABI void __annotate_shrink_back(size_type __old_size, size_type __old_start) const _NOEXCEPT {
1054    (void)__old_size;
1055    (void)__old_start;
1056#ifndef _LIBCPP_HAS_NO_ASAN
1057    __annotate_from_to(__old_start + size(), __old_start + __old_size, __asan_poison, __asan_back_moved);
1058#endif
1059  }
1060
1061  _LIBCPP_HIDE_FROM_ABI void __annotate_poison_block(const void* __beginning, const void* __end) const _NOEXCEPT {
1062    std::__annotate_double_ended_contiguous_container<_Allocator>(__beginning, __end, __beginning, __end, __end, __end);
1063  }
1064
1065  _LIBCPP_HIDE_FROM_ABI void
1066  __annotate_whole_block(size_t __block_index, __asan_annotation_type __annotation_type) const _NOEXCEPT {
1067    (void)__block_index;
1068    (void)__annotation_type;
1069#ifndef _LIBCPP_HAS_NO_ASAN
1070    __map_const_iterator __block_it = __map_.begin() + __block_index;
1071    const void* __block_start       = std::__to_address(*__block_it);
1072    const void* __block_end         = std::__to_address(*__block_it + __block_size);
1073
1074    if (__annotation_type == __asan_poison)
1075      __annotate_poison_block(__block_start, __block_end);
1076    else {
1077      std::__annotate_double_ended_contiguous_container<_Allocator>(
1078          __block_start, __block_end, __block_start, __block_start, __block_start, __block_end);
1079    }
1080#endif
1081  }
1082#if !defined(_LIBCPP_HAS_NO_ASAN)
1083
1084public:
1085  _LIBCPP_HIDE_FROM_ABI bool __verify_asan_annotations() const _NOEXCEPT {
1086    // This function tests deque object annotations.
1087    if (empty()) {
1088      for (__map_const_iterator __it = __map_.begin(); __it != __map_.end(); ++__it) {
1089        if (!__sanitizer_verify_double_ended_contiguous_container(
1090                std::__to_address(*__it),
1091                std::__to_address(*__it),
1092                std::__to_address(*__it),
1093                std::__to_address(*__it + __block_size)))
1094          return false;
1095      }
1096
1097      return true;
1098    }
1099
1100    size_type __end                 = __start_ + size();
1101    __map_const_iterator __first_mp = __map_.begin() + __start_ / __block_size;
1102    __map_const_iterator __last_mp  = __map_.begin() + (__end - 1) / __block_size;
1103
1104    // Pointers to first and after last elements
1105    // Those can be in different deque blocks
1106    const void* __p_beg = std::__to_address(*__first_mp + (__start_ % __block_size));
1107    const void* __p_end =
1108        std::__to_address(*__last_mp + ((__end % __block_size == 0) ? __block_size : __end % __block_size));
1109
1110    for (__map_const_iterator __it = __map_.begin(); __it != __map_.end(); ++__it) {
1111      // Go over all blocks, find the place we are in and verify its annotations
1112      // Note that __p_end points *behind* the last item.
1113
1114      // - blocks before the first block with container elements
1115      // - first block with items
1116      // - last block with items
1117      // - blocks after last block with ciontainer elements
1118
1119      // Is the block before or after deque blocks that contain elements?
1120      if (__it < __first_mp || __it > __last_mp) {
1121        if (!__sanitizer_verify_double_ended_contiguous_container(
1122                std::__to_address(*__it),
1123                std::__to_address(*__it),
1124                std::__to_address(*__it),
1125                std::__to_address(*__it + __block_size)))
1126          return false;
1127      } else {
1128        const void* __containers_buffer_beg = (__it == __first_mp) ? __p_beg : (const void*)std::__to_address(*__it);
1129        const void* __containers_buffer_end =
1130            (__it == __last_mp) ? __p_end : (const void*)std::__to_address(*__it + __block_size);
1131        if (!__sanitizer_verify_double_ended_contiguous_container(
1132                std::__to_address(*__it),
1133                __containers_buffer_beg,
1134                __containers_buffer_end,
1135                std::__to_address(*__it + __block_size))) {
1136          return false;
1137        }
1138      }
1139    }
1140    return true;
1141  }
1142
1143private:
1144#endif // _LIBCPP_VERIFY_ASAN_DEQUE_ANNOTATIONS
1145  _LIBCPP_HIDE_FROM_ABI bool __maybe_remove_front_spare(bool __keep_one = true) {
1146    if (__front_spare_blocks() >= 2 || (!__keep_one && __front_spare_blocks())) {
1147      __annotate_whole_block(0, __asan_unposion);
1148      __alloc_traits::deallocate(__alloc(), __map_.front(), __block_size);
1149      __map_.pop_front();
1150      __start_ -= __block_size;
1151      return true;
1152    }
1153    return false;
1154  }
1155
1156  _LIBCPP_HIDE_FROM_ABI bool __maybe_remove_back_spare(bool __keep_one = true) {
1157    if (__back_spare_blocks() >= 2 || (!__keep_one && __back_spare_blocks())) {
1158      __annotate_whole_block(__map_.size() - 1, __asan_unposion);
1159      __alloc_traits::deallocate(__alloc(), __map_.back(), __block_size);
1160      __map_.pop_back();
1161      return true;
1162    }
1163    return false;
1164  }
1165
1166  template <class _Iterator, class _Sentinel>
1167  _LIBCPP_HIDE_FROM_ABI void __assign_with_sentinel(_Iterator __f, _Sentinel __l);
1168
1169  template <class _RandomAccessIterator>
1170  _LIBCPP_HIDE_FROM_ABI void __assign_with_size_random_access(_RandomAccessIterator __f, difference_type __n);
1171  template <class _Iterator>
1172  _LIBCPP_HIDE_FROM_ABI void __assign_with_size(_Iterator __f, difference_type __n);
1173
1174  template <class _Iterator, class _Sentinel>
1175  _LIBCPP_HIDE_FROM_ABI iterator __insert_with_sentinel(const_iterator __p, _Iterator __f, _Sentinel __l);
1176
1177  template <class _Iterator>
1178  _LIBCPP_HIDE_FROM_ABI iterator __insert_with_size(const_iterator __p, _Iterator __f, size_type __n);
1179
1180  template <class _BiIter, class _Sentinel>
1181  _LIBCPP_HIDE_FROM_ABI iterator
1182  __insert_bidirectional(const_iterator __p, _BiIter __f, _Sentinel __sent, size_type __n);
1183  template <class _BiIter>
1184  _LIBCPP_HIDE_FROM_ABI iterator __insert_bidirectional(const_iterator __p, _BiIter __f, _BiIter __l, size_type __n);
1185
1186  template <class _InpIter, __enable_if_t<__has_exactly_input_iterator_category<_InpIter>::value, int> = 0>
1187  _LIBCPP_HIDE_FROM_ABI void __append(_InpIter __f, _InpIter __l);
1188  template <class _ForIter, __enable_if_t<__has_forward_iterator_category<_ForIter>::value, int> = 0>
1189  _LIBCPP_HIDE_FROM_ABI void __append(_ForIter __f, _ForIter __l);
1190
1191  template <class _InputIterator>
1192  _LIBCPP_HIDE_FROM_ABI void __append_with_size(_InputIterator __from, size_type __n);
1193  template <class _InputIterator, class _Sentinel>
1194  _LIBCPP_HIDE_FROM_ABI void __append_with_sentinel(_InputIterator __f, _Sentinel __l);
1195
1196  _LIBCPP_HIDE_FROM_ABI void __append(size_type __n);
1197  _LIBCPP_HIDE_FROM_ABI void __append(size_type __n, const value_type& __v);
1198  _LIBCPP_HIDE_FROM_ABI void __erase_to_end(const_iterator __f);
1199  _LIBCPP_HIDE_FROM_ABI void __add_front_capacity();
1200  _LIBCPP_HIDE_FROM_ABI void __add_front_capacity(size_type __n);
1201  _LIBCPP_HIDE_FROM_ABI void __add_back_capacity();
1202  _LIBCPP_HIDE_FROM_ABI void __add_back_capacity(size_type __n);
1203  _LIBCPP_HIDE_FROM_ABI iterator __move_and_check(iterator __f, iterator __l, iterator __r, const_pointer& __vt);
1204  _LIBCPP_HIDE_FROM_ABI iterator
1205  __move_backward_and_check(iterator __f, iterator __l, iterator __r, const_pointer& __vt);
1206  _LIBCPP_HIDE_FROM_ABI void __move_construct_and_check(iterator __f, iterator __l, iterator __r, const_pointer& __vt);
1207  _LIBCPP_HIDE_FROM_ABI void
1208  __move_construct_backward_and_check(iterator __f, iterator __l, iterator __r, const_pointer& __vt);
1209
1210  _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const deque& __c) {
1211    __copy_assign_alloc(__c, integral_constant<bool, __alloc_traits::propagate_on_container_copy_assignment::value>());
1212  }
1213
1214  _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const deque& __c, true_type) {
1215    if (__alloc() != __c.__alloc()) {
1216      clear();
1217      shrink_to_fit();
1218    }
1219    __alloc()        = __c.__alloc();
1220    __map_.__alloc() = __c.__map_.__alloc();
1221  }
1222
1223  _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const deque&, false_type) {}
1224
1225  _LIBCPP_HIDE_FROM_ABI void __move_assign(deque& __c, true_type)
1226      _NOEXCEPT_(is_nothrow_move_assignable<allocator_type>::value);
1227  _LIBCPP_HIDE_FROM_ABI void __move_assign(deque& __c, false_type);
1228};
1229
1230template <class _Tp, class _Alloc>
1231_LIBCPP_CONSTEXPR const typename allocator_traits<_Alloc>::difference_type deque<_Tp, _Alloc>::__block_size =
1232    __deque_block_size<value_type, difference_type>::value;
1233
1234#if _LIBCPP_STD_VER >= 17
1235template <class _InputIterator,
1236          class _Alloc = allocator<__iter_value_type<_InputIterator>>,
1237          class        = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
1238          class        = enable_if_t<__is_allocator<_Alloc>::value> >
1239deque(_InputIterator, _InputIterator) -> deque<__iter_value_type<_InputIterator>, _Alloc>;
1240
1241template <class _InputIterator,
1242          class _Alloc,
1243          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
1244          class = enable_if_t<__is_allocator<_Alloc>::value> >
1245deque(_InputIterator, _InputIterator, _Alloc) -> deque<__iter_value_type<_InputIterator>, _Alloc>;
1246#endif
1247
1248#if _LIBCPP_STD_VER >= 23
1249template <ranges::input_range _Range,
1250          class _Alloc = allocator<ranges::range_value_t<_Range>>,
1251          class        = enable_if_t<__is_allocator<_Alloc>::value> >
1252deque(from_range_t, _Range&&, _Alloc = _Alloc()) -> deque<ranges::range_value_t<_Range>, _Alloc>;
1253#endif
1254
1255template <class _Tp, class _Allocator>
1256deque<_Tp, _Allocator>::deque(size_type __n) : __start_(0), __size_(0, __default_init_tag()) {
1257  __annotate_new(0);
1258  if (__n > 0)
1259    __append(__n);
1260}
1261
1262#if _LIBCPP_STD_VER >= 14
1263template <class _Tp, class _Allocator>
1264deque<_Tp, _Allocator>::deque(size_type __n, const _Allocator& __a)
1265    : __map_(__pointer_allocator(__a)), __start_(0), __size_(0, __a) {
1266  __annotate_new(0);
1267  if (__n > 0)
1268    __append(__n);
1269}
1270#endif
1271
1272template <class _Tp, class _Allocator>
1273deque<_Tp, _Allocator>::deque(size_type __n, const value_type& __v) : __start_(0), __size_(0, __default_init_tag()) {
1274  __annotate_new(0);
1275  if (__n > 0)
1276    __append(__n, __v);
1277}
1278
1279template <class _Tp, class _Allocator>
1280template <class _InputIter, __enable_if_t<__has_input_iterator_category<_InputIter>::value, int> >
1281deque<_Tp, _Allocator>::deque(_InputIter __f, _InputIter __l) : __start_(0), __size_(0, __default_init_tag()) {
1282  __annotate_new(0);
1283  __append(__f, __l);
1284}
1285
1286template <class _Tp, class _Allocator>
1287template <class _InputIter, __enable_if_t<__has_input_iterator_category<_InputIter>::value, int> >
1288deque<_Tp, _Allocator>::deque(_InputIter __f, _InputIter __l, const allocator_type& __a)
1289    : __map_(__pointer_allocator(__a)), __start_(0), __size_(0, __a) {
1290  __annotate_new(0);
1291  __append(__f, __l);
1292}
1293
1294template <class _Tp, class _Allocator>
1295deque<_Tp, _Allocator>::deque(const deque& __c)
1296    : __map_(__pointer_allocator(__alloc_traits::select_on_container_copy_construction(__c.__alloc()))),
1297      __start_(0),
1298      __size_(0, __map_.__alloc()) {
1299  __annotate_new(0);
1300  __append(__c.begin(), __c.end());
1301}
1302
1303template <class _Tp, class _Allocator>
1304deque<_Tp, _Allocator>::deque(const deque& __c, const __type_identity_t<allocator_type>& __a)
1305    : __map_(__pointer_allocator(__a)), __start_(0), __size_(0, __a) {
1306  __annotate_new(0);
1307  __append(__c.begin(), __c.end());
1308}
1309
1310template <class _Tp, class _Allocator>
1311deque<_Tp, _Allocator>& deque<_Tp, _Allocator>::operator=(const deque& __c) {
1312  if (this != std::addressof(__c)) {
1313    __copy_assign_alloc(__c);
1314    assign(__c.begin(), __c.end());
1315  }
1316  return *this;
1317}
1318
1319#ifndef _LIBCPP_CXX03_LANG
1320
1321template <class _Tp, class _Allocator>
1322deque<_Tp, _Allocator>::deque(initializer_list<value_type> __il) : __start_(0), __size_(0, __default_init_tag()) {
1323  __annotate_new(0);
1324  __append(__il.begin(), __il.end());
1325}
1326
1327template <class _Tp, class _Allocator>
1328deque<_Tp, _Allocator>::deque(initializer_list<value_type> __il, const allocator_type& __a)
1329    : __map_(__pointer_allocator(__a)), __start_(0), __size_(0, __a) {
1330  __annotate_new(0);
1331  __append(__il.begin(), __il.end());
1332}
1333
1334template <class _Tp, class _Allocator>
1335inline deque<_Tp, _Allocator>::deque(deque&& __c) noexcept(is_nothrow_move_constructible<allocator_type>::value)
1336    : __map_(std::move(__c.__map_)), __start_(std::move(__c.__start_)), __size_(std::move(__c.__size_)) {
1337  __c.__start_ = 0;
1338  __c.__size() = 0;
1339}
1340
1341template <class _Tp, class _Allocator>
1342inline deque<_Tp, _Allocator>::deque(deque&& __c, const __type_identity_t<allocator_type>& __a)
1343    : __map_(std::move(__c.__map_), __pointer_allocator(__a)),
1344      __start_(std::move(__c.__start_)),
1345      __size_(std::move(__c.__size()), __a) {
1346  if (__a == __c.__alloc()) {
1347    __c.__start_ = 0;
1348    __c.__size() = 0;
1349  } else {
1350    __map_.clear();
1351    __start_ = 0;
1352    __size() = 0;
1353    typedef move_iterator<iterator> _Ip;
1354    assign(_Ip(__c.begin()), _Ip(__c.end()));
1355  }
1356}
1357
1358template <class _Tp, class _Allocator>
1359inline deque<_Tp, _Allocator>& deque<_Tp, _Allocator>::operator=(deque&& __c) noexcept(
1360    __alloc_traits::propagate_on_container_move_assignment::value &&
1361    is_nothrow_move_assignable<allocator_type>::value) {
1362  __move_assign(__c, integral_constant<bool, __alloc_traits::propagate_on_container_move_assignment::value>());
1363  return *this;
1364}
1365
1366template <class _Tp, class _Allocator>
1367void deque<_Tp, _Allocator>::__move_assign(deque& __c, false_type) {
1368  if (__alloc() != __c.__alloc()) {
1369    typedef move_iterator<iterator> _Ip;
1370    assign(_Ip(__c.begin()), _Ip(__c.end()));
1371  } else
1372    __move_assign(__c, true_type());
1373}
1374
1375template <class _Tp, class _Allocator>
1376void deque<_Tp, _Allocator>::__move_assign(deque& __c,
1377                                           true_type) noexcept(is_nothrow_move_assignable<allocator_type>::value) {
1378  clear();
1379  shrink_to_fit();
1380  __move_assign(__c);
1381}
1382
1383#endif // _LIBCPP_CXX03_LANG
1384
1385template <class _Tp, class _Allocator>
1386template <class _InputIter,
1387          __enable_if_t<__has_input_iterator_category<_InputIter>::value &&
1388                            !__has_random_access_iterator_category<_InputIter>::value,
1389                        int> >
1390void deque<_Tp, _Allocator>::assign(_InputIter __f, _InputIter __l) {
1391  __assign_with_sentinel(__f, __l);
1392}
1393
1394template <class _Tp, class _Allocator>
1395template <class _Iterator, class _Sentinel>
1396_LIBCPP_HIDE_FROM_ABI void deque<_Tp, _Allocator>::__assign_with_sentinel(_Iterator __f, _Sentinel __l) {
1397  iterator __i = begin();
1398  iterator __e = end();
1399  for (; __f != __l && __i != __e; ++__f, (void)++__i)
1400    *__i = *__f;
1401  if (__f != __l)
1402    __append_with_sentinel(std::move(__f), std::move(__l));
1403  else
1404    __erase_to_end(__i);
1405}
1406
1407template <class _Tp, class _Allocator>
1408template <class _RAIter, __enable_if_t<__has_random_access_iterator_category<_RAIter>::value, int> >
1409void deque<_Tp, _Allocator>::assign(_RAIter __f, _RAIter __l) {
1410  __assign_with_size_random_access(__f, __l - __f);
1411}
1412
1413template <class _Tp, class _Allocator>
1414template <class _RandomAccessIterator>
1415_LIBCPP_HIDE_FROM_ABI void
1416deque<_Tp, _Allocator>::__assign_with_size_random_access(_RandomAccessIterator __f, difference_type __n) {
1417  if (static_cast<size_type>(__n) > size()) {
1418    auto __l = __f + size();
1419    std::copy(__f, __l, begin());
1420    __append_with_size(__l, __n - size());
1421  } else
1422    __erase_to_end(std::copy_n(__f, __n, begin()));
1423}
1424
1425template <class _Tp, class _Allocator>
1426template <class _Iterator>
1427_LIBCPP_HIDE_FROM_ABI void deque<_Tp, _Allocator>::__assign_with_size(_Iterator __f, difference_type __n) {
1428  if (static_cast<size_type>(__n) > size()) {
1429    auto __added_size = __n - size();
1430
1431    auto __i = begin();
1432    for (auto __count = size(); __count != 0; --__count) {
1433      *__i++ = *__f++;
1434    }
1435
1436    __append_with_size(__f, __added_size);
1437
1438  } else {
1439    __erase_to_end(std::copy_n(__f, __n, begin()));
1440  }
1441}
1442
1443template <class _Tp, class _Allocator>
1444void deque<_Tp, _Allocator>::assign(size_type __n, const value_type& __v) {
1445  if (__n > size()) {
1446    std::fill_n(begin(), size(), __v);
1447    __n -= size();
1448    __append(__n, __v);
1449  } else
1450    __erase_to_end(std::fill_n(begin(), __n, __v));
1451}
1452
1453template <class _Tp, class _Allocator>
1454inline _Allocator deque<_Tp, _Allocator>::get_allocator() const _NOEXCEPT {
1455  return __alloc();
1456}
1457
1458template <class _Tp, class _Allocator>
1459void deque<_Tp, _Allocator>::resize(size_type __n) {
1460  if (__n > size())
1461    __append(__n - size());
1462  else if (__n < size())
1463    __erase_to_end(begin() + __n);
1464}
1465
1466template <class _Tp, class _Allocator>
1467void deque<_Tp, _Allocator>::resize(size_type __n, const value_type& __v) {
1468  if (__n > size())
1469    __append(__n - size(), __v);
1470  else if (__n < size())
1471    __erase_to_end(begin() + __n);
1472}
1473
1474template <class _Tp, class _Allocator>
1475void deque<_Tp, _Allocator>::shrink_to_fit() _NOEXCEPT {
1476  allocator_type& __a = __alloc();
1477  if (empty()) {
1478    __annotate_delete();
1479    while (__map_.size() > 0) {
1480      __alloc_traits::deallocate(__a, __map_.back(), __block_size);
1481      __map_.pop_back();
1482    }
1483    __start_ = 0;
1484  } else {
1485    __maybe_remove_front_spare(/*__keep_one=*/false);
1486    __maybe_remove_back_spare(/*__keep_one=*/false);
1487  }
1488  __map_.shrink_to_fit();
1489}
1490
1491template <class _Tp, class _Allocator>
1492inline typename deque<_Tp, _Allocator>::reference deque<_Tp, _Allocator>::operator[](size_type __i) _NOEXCEPT {
1493  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__i < size(), "deque::operator[] index out of bounds");
1494  size_type __p = __start_ + __i;
1495  return *(*(__map_.begin() + __p / __block_size) + __p % __block_size);
1496}
1497
1498template <class _Tp, class _Allocator>
1499inline typename deque<_Tp, _Allocator>::const_reference
1500deque<_Tp, _Allocator>::operator[](size_type __i) const _NOEXCEPT {
1501  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__i < size(), "deque::operator[] index out of bounds");
1502  size_type __p = __start_ + __i;
1503  return *(*(__map_.begin() + __p / __block_size) + __p % __block_size);
1504}
1505
1506template <class _Tp, class _Allocator>
1507inline typename deque<_Tp, _Allocator>::reference deque<_Tp, _Allocator>::at(size_type __i) {
1508  if (__i >= size())
1509    std::__throw_out_of_range("deque");
1510  size_type __p = __start_ + __i;
1511  return *(*(__map_.begin() + __p / __block_size) + __p % __block_size);
1512}
1513
1514template <class _Tp, class _Allocator>
1515inline typename deque<_Tp, _Allocator>::const_reference deque<_Tp, _Allocator>::at(size_type __i) const {
1516  if (__i >= size())
1517    std::__throw_out_of_range("deque");
1518  size_type __p = __start_ + __i;
1519  return *(*(__map_.begin() + __p / __block_size) + __p % __block_size);
1520}
1521
1522template <class _Tp, class _Allocator>
1523inline typename deque<_Tp, _Allocator>::reference deque<_Tp, _Allocator>::front() _NOEXCEPT {
1524  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "deque::front called on an empty deque");
1525  return *(*(__map_.begin() + __start_ / __block_size) + __start_ % __block_size);
1526}
1527
1528template <class _Tp, class _Allocator>
1529inline typename deque<_Tp, _Allocator>::const_reference deque<_Tp, _Allocator>::front() const _NOEXCEPT {
1530  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "deque::front called on an empty deque");
1531  return *(*(__map_.begin() + __start_ / __block_size) + __start_ % __block_size);
1532}
1533
1534template <class _Tp, class _Allocator>
1535inline typename deque<_Tp, _Allocator>::reference deque<_Tp, _Allocator>::back() _NOEXCEPT {
1536  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "deque::back called on an empty deque");
1537  size_type __p = size() + __start_ - 1;
1538  return *(*(__map_.begin() + __p / __block_size) + __p % __block_size);
1539}
1540
1541template <class _Tp, class _Allocator>
1542inline typename deque<_Tp, _Allocator>::const_reference deque<_Tp, _Allocator>::back() const _NOEXCEPT {
1543  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "deque::back called on an empty deque");
1544  size_type __p = size() + __start_ - 1;
1545  return *(*(__map_.begin() + __p / __block_size) + __p % __block_size);
1546}
1547
1548template <class _Tp, class _Allocator>
1549void deque<_Tp, _Allocator>::push_back(const value_type& __v) {
1550  allocator_type& __a = __alloc();
1551  if (__back_spare() == 0)
1552    __add_back_capacity();
1553  // __back_spare() >= 1
1554  __annotate_increase_back(1);
1555  __alloc_traits::construct(__a, std::addressof(*end()), __v);
1556  ++__size();
1557}
1558
1559template <class _Tp, class _Allocator>
1560void deque<_Tp, _Allocator>::push_front(const value_type& __v) {
1561  allocator_type& __a = __alloc();
1562  if (__front_spare() == 0)
1563    __add_front_capacity();
1564  // __front_spare() >= 1
1565  __annotate_increase_front(1);
1566  __alloc_traits::construct(__a, std::addressof(*--begin()), __v);
1567  --__start_;
1568  ++__size();
1569}
1570
1571#ifndef _LIBCPP_CXX03_LANG
1572template <class _Tp, class _Allocator>
1573void deque<_Tp, _Allocator>::push_back(value_type&& __v) {
1574  allocator_type& __a = __alloc();
1575  if (__back_spare() == 0)
1576    __add_back_capacity();
1577  // __back_spare() >= 1
1578  __annotate_increase_back(1);
1579  __alloc_traits::construct(__a, std::addressof(*end()), std::move(__v));
1580  ++__size();
1581}
1582
1583template <class _Tp, class _Allocator>
1584template <class... _Args>
1585#  if _LIBCPP_STD_VER >= 17
1586typename deque<_Tp, _Allocator>::reference
1587#  else
1588void
1589#  endif
1590deque<_Tp, _Allocator>::emplace_back(_Args&&... __args) {
1591  allocator_type& __a = __alloc();
1592  if (__back_spare() == 0)
1593    __add_back_capacity();
1594  // __back_spare() >= 1
1595  __annotate_increase_back(1);
1596  __alloc_traits::construct(__a, std::addressof(*end()), std::forward<_Args>(__args)...);
1597  ++__size();
1598#  if _LIBCPP_STD_VER >= 17
1599  return *--end();
1600#  endif
1601}
1602
1603template <class _Tp, class _Allocator>
1604void deque<_Tp, _Allocator>::push_front(value_type&& __v) {
1605  allocator_type& __a = __alloc();
1606  if (__front_spare() == 0)
1607    __add_front_capacity();
1608  // __front_spare() >= 1
1609  __annotate_increase_front(1);
1610  __alloc_traits::construct(__a, std::addressof(*--begin()), std::move(__v));
1611  --__start_;
1612  ++__size();
1613}
1614
1615template <class _Tp, class _Allocator>
1616template <class... _Args>
1617#  if _LIBCPP_STD_VER >= 17
1618typename deque<_Tp, _Allocator>::reference
1619#  else
1620void
1621#  endif
1622deque<_Tp, _Allocator>::emplace_front(_Args&&... __args) {
1623  allocator_type& __a = __alloc();
1624  if (__front_spare() == 0)
1625    __add_front_capacity();
1626  // __front_spare() >= 1
1627  __annotate_increase_front(1);
1628  __alloc_traits::construct(__a, std::addressof(*--begin()), std::forward<_Args>(__args)...);
1629  --__start_;
1630  ++__size();
1631#  if _LIBCPP_STD_VER >= 17
1632  return *begin();
1633#  endif
1634}
1635
1636template <class _Tp, class _Allocator>
1637typename deque<_Tp, _Allocator>::iterator deque<_Tp, _Allocator>::insert(const_iterator __p, value_type&& __v) {
1638  size_type __pos     = __p - begin();
1639  size_type __to_end  = size() - __pos;
1640  allocator_type& __a = __alloc();
1641  if (__pos < __to_end) { // insert by shifting things backward
1642    if (__front_spare() == 0)
1643      __add_front_capacity();
1644    // __front_spare() >= 1
1645    __annotate_increase_front(1);
1646    if (__pos == 0) {
1647      __alloc_traits::construct(__a, std::addressof(*--begin()), std::move(__v));
1648      --__start_;
1649      ++__size();
1650    } else {
1651      iterator __b   = begin();
1652      iterator __bm1 = std::prev(__b);
1653      __alloc_traits::construct(__a, std::addressof(*__bm1), std::move(*__b));
1654      --__start_;
1655      ++__size();
1656      if (__pos > 1)
1657        __b = std::move(std::next(__b), __b + __pos, __b);
1658      *__b = std::move(__v);
1659    }
1660  } else { // insert by shifting things forward
1661    if (__back_spare() == 0)
1662      __add_back_capacity();
1663    // __back_capacity >= 1
1664    __annotate_increase_back(1);
1665    size_type __de = size() - __pos;
1666    if (__de == 0) {
1667      __alloc_traits::construct(__a, std::addressof(*end()), std::move(__v));
1668      ++__size();
1669    } else {
1670      iterator __e   = end();
1671      iterator __em1 = std::prev(__e);
1672      __alloc_traits::construct(__a, std::addressof(*__e), std::move(*__em1));
1673      ++__size();
1674      if (__de > 1)
1675        __e = std::move_backward(__e - __de, __em1, __e);
1676      *--__e = std::move(__v);
1677    }
1678  }
1679  return begin() + __pos;
1680}
1681
1682template <class _Tp, class _Allocator>
1683template <class... _Args>
1684typename deque<_Tp, _Allocator>::iterator deque<_Tp, _Allocator>::emplace(const_iterator __p, _Args&&... __args) {
1685  size_type __pos     = __p - begin();
1686  size_type __to_end  = size() - __pos;
1687  allocator_type& __a = __alloc();
1688  if (__pos < __to_end) { // insert by shifting things backward
1689    if (__front_spare() == 0)
1690      __add_front_capacity();
1691    // __front_spare() >= 1
1692    __annotate_increase_front(1);
1693    if (__pos == 0) {
1694      __alloc_traits::construct(__a, std::addressof(*--begin()), std::forward<_Args>(__args)...);
1695      --__start_;
1696      ++__size();
1697    } else {
1698      __temp_value<value_type, _Allocator> __tmp(__alloc(), std::forward<_Args>(__args)...);
1699      iterator __b   = begin();
1700      iterator __bm1 = std::prev(__b);
1701      __alloc_traits::construct(__a, std::addressof(*__bm1), std::move(*__b));
1702      --__start_;
1703      ++__size();
1704      if (__pos > 1)
1705        __b = std::move(std::next(__b), __b + __pos, __b);
1706      *__b = std::move(__tmp.get());
1707    }
1708  } else { // insert by shifting things forward
1709    if (__back_spare() == 0)
1710      __add_back_capacity();
1711    // __back_capacity >= 1
1712    __annotate_increase_back(1);
1713    size_type __de = size() - __pos;
1714    if (__de == 0) {
1715      __alloc_traits::construct(__a, std::addressof(*end()), std::forward<_Args>(__args)...);
1716      ++__size();
1717    } else {
1718      __temp_value<value_type, _Allocator> __tmp(__alloc(), std::forward<_Args>(__args)...);
1719      iterator __e   = end();
1720      iterator __em1 = std::prev(__e);
1721      __alloc_traits::construct(__a, std::addressof(*__e), std::move(*__em1));
1722      ++__size();
1723      if (__de > 1)
1724        __e = std::move_backward(__e - __de, __em1, __e);
1725      *--__e = std::move(__tmp.get());
1726    }
1727  }
1728  return begin() + __pos;
1729}
1730
1731#endif // _LIBCPP_CXX03_LANG
1732
1733template <class _Tp, class _Allocator>
1734typename deque<_Tp, _Allocator>::iterator deque<_Tp, _Allocator>::insert(const_iterator __p, const value_type& __v) {
1735  size_type __pos     = __p - begin();
1736  size_type __to_end  = size() - __pos;
1737  allocator_type& __a = __alloc();
1738  if (__pos < __to_end) { // insert by shifting things backward
1739    if (__front_spare() == 0)
1740      __add_front_capacity();
1741    // __front_spare() >= 1
1742    __annotate_increase_front(1);
1743    if (__pos == 0) {
1744      __alloc_traits::construct(__a, std::addressof(*--begin()), __v);
1745      --__start_;
1746      ++__size();
1747    } else {
1748      const_pointer __vt = pointer_traits<const_pointer>::pointer_to(__v);
1749      iterator __b       = begin();
1750      iterator __bm1     = std::prev(__b);
1751      if (__vt == pointer_traits<const_pointer>::pointer_to(*__b))
1752        __vt = pointer_traits<const_pointer>::pointer_to(*__bm1);
1753      __alloc_traits::construct(__a, std::addressof(*__bm1), std::move(*__b));
1754      --__start_;
1755      ++__size();
1756      if (__pos > 1)
1757        __b = __move_and_check(std::next(__b), __b + __pos, __b, __vt);
1758      *__b = *__vt;
1759    }
1760  } else { // insert by shifting things forward
1761    if (__back_spare() == 0)
1762      __add_back_capacity();
1763    // __back_capacity >= 1
1764    __annotate_increase_back(1);
1765    size_type __de = size() - __pos;
1766    if (__de == 0) {
1767      __alloc_traits::construct(__a, std::addressof(*end()), __v);
1768      ++__size();
1769    } else {
1770      const_pointer __vt = pointer_traits<const_pointer>::pointer_to(__v);
1771      iterator __e       = end();
1772      iterator __em1     = std::prev(__e);
1773      if (__vt == pointer_traits<const_pointer>::pointer_to(*__em1))
1774        __vt = pointer_traits<const_pointer>::pointer_to(*__e);
1775      __alloc_traits::construct(__a, std::addressof(*__e), std::move(*__em1));
1776      ++__size();
1777      if (__de > 1)
1778        __e = __move_backward_and_check(__e - __de, __em1, __e, __vt);
1779      *--__e = *__vt;
1780    }
1781  }
1782  return begin() + __pos;
1783}
1784
1785template <class _Tp, class _Allocator>
1786typename deque<_Tp, _Allocator>::iterator
1787deque<_Tp, _Allocator>::insert(const_iterator __p, size_type __n, const value_type& __v) {
1788  size_type __pos     = __p - begin();
1789  size_type __to_end  = __size() - __pos;
1790  allocator_type& __a = __alloc();
1791  if (__pos < __to_end) { // insert by shifting things backward
1792    if (__n > __front_spare())
1793      __add_front_capacity(__n - __front_spare());
1794    // __n <= __front_spare()
1795    __annotate_increase_front(__n);
1796    iterator __old_begin = begin();
1797    iterator __i         = __old_begin;
1798    if (__n > __pos) {
1799      for (size_type __m = __n - __pos; __m; --__m, --__start_, ++__size())
1800        __alloc_traits::construct(__a, std::addressof(*--__i), __v);
1801      __n = __pos;
1802    }
1803    if (__n > 0) {
1804      const_pointer __vt = pointer_traits<const_pointer>::pointer_to(__v);
1805      iterator __obn     = __old_begin + __n;
1806      __move_construct_backward_and_check(__old_begin, __obn, __i, __vt);
1807      if (__n < __pos)
1808        __old_begin = __move_and_check(__obn, __old_begin + __pos, __old_begin, __vt);
1809      std::fill_n(__old_begin, __n, *__vt);
1810    }
1811  } else { // insert by shifting things forward
1812    size_type __back_capacity = __back_spare();
1813    if (__n > __back_capacity)
1814      __add_back_capacity(__n - __back_capacity);
1815    // __n <= __back_capacity
1816    __annotate_increase_back(__n);
1817    iterator __old_end = end();
1818    iterator __i       = __old_end;
1819    size_type __de     = size() - __pos;
1820    if (__n > __de) {
1821      for (size_type __m = __n - __de; __m; --__m, (void)++__i, ++__size())
1822        __alloc_traits::construct(__a, std::addressof(*__i), __v);
1823      __n = __de;
1824    }
1825    if (__n > 0) {
1826      const_pointer __vt = pointer_traits<const_pointer>::pointer_to(__v);
1827      iterator __oen     = __old_end - __n;
1828      __move_construct_and_check(__oen, __old_end, __i, __vt);
1829      if (__n < __de)
1830        __old_end = __move_backward_and_check(__old_end - __de, __oen, __old_end, __vt);
1831      std::fill_n(__old_end - __n, __n, *__vt);
1832    }
1833  }
1834  return begin() + __pos;
1835}
1836
1837template <class _Tp, class _Allocator>
1838template <class _InputIter, __enable_if_t<__has_exactly_input_iterator_category<_InputIter>::value, int> >
1839typename deque<_Tp, _Allocator>::iterator
1840deque<_Tp, _Allocator>::insert(const_iterator __p, _InputIter __f, _InputIter __l) {
1841  return __insert_with_sentinel(__p, __f, __l);
1842}
1843
1844template <class _Tp, class _Allocator>
1845template <class _Iterator, class _Sentinel>
1846_LIBCPP_HIDE_FROM_ABI typename deque<_Tp, _Allocator>::iterator
1847deque<_Tp, _Allocator>::__insert_with_sentinel(const_iterator __p, _Iterator __f, _Sentinel __l) {
1848  __split_buffer<value_type, allocator_type&> __buf(__alloc());
1849  __buf.__construct_at_end_with_sentinel(std::move(__f), std::move(__l));
1850  typedef typename __split_buffer<value_type, allocator_type&>::iterator __bi;
1851  return insert(__p, move_iterator<__bi>(__buf.begin()), move_iterator<__bi>(__buf.end()));
1852}
1853
1854template <class _Tp, class _Allocator>
1855template <class _ForwardIterator, __enable_if_t<__has_exactly_forward_iterator_category<_ForwardIterator>::value, int> >
1856typename deque<_Tp, _Allocator>::iterator
1857deque<_Tp, _Allocator>::insert(const_iterator __p, _ForwardIterator __f, _ForwardIterator __l) {
1858  return __insert_with_size(__p, __f, std::distance(__f, __l));
1859}
1860
1861template <class _Tp, class _Allocator>
1862template <class _Iterator>
1863_LIBCPP_HIDE_FROM_ABI typename deque<_Tp, _Allocator>::iterator
1864deque<_Tp, _Allocator>::__insert_with_size(const_iterator __p, _Iterator __f, size_type __n) {
1865  __split_buffer<value_type, allocator_type&> __buf(__n, 0, __alloc());
1866  __buf.__construct_at_end_with_size(__f, __n);
1867  typedef typename __split_buffer<value_type, allocator_type&>::iterator __fwd;
1868  return insert(__p, move_iterator<__fwd>(__buf.begin()), move_iterator<__fwd>(__buf.end()));
1869}
1870
1871template <class _Tp, class _Allocator>
1872template <class _BiIter, __enable_if_t<__has_bidirectional_iterator_category<_BiIter>::value, int> >
1873typename deque<_Tp, _Allocator>::iterator deque<_Tp, _Allocator>::insert(const_iterator __p, _BiIter __f, _BiIter __l) {
1874  return __insert_bidirectional(__p, __f, __l, std::distance(__f, __l));
1875}
1876
1877template <class _Tp, class _Allocator>
1878template <class _BiIter, class _Sentinel>
1879_LIBCPP_HIDE_FROM_ABI typename deque<_Tp, _Allocator>::iterator
1880deque<_Tp, _Allocator>::__insert_bidirectional(const_iterator __p, _BiIter __f, _Sentinel, size_type __n) {
1881  return __insert_bidirectional(__p, __f, std::next(__f, __n), __n);
1882}
1883
1884template <class _Tp, class _Allocator>
1885template <class _BiIter>
1886_LIBCPP_HIDE_FROM_ABI typename deque<_Tp, _Allocator>::iterator
1887deque<_Tp, _Allocator>::__insert_bidirectional(const_iterator __p, _BiIter __f, _BiIter __l, size_type __n) {
1888  size_type __pos     = __p - begin();
1889  size_type __to_end  = size() - __pos;
1890  allocator_type& __a = __alloc();
1891  if (__pos < __to_end) { // insert by shifting things backward
1892    if (__n > __front_spare())
1893      __add_front_capacity(__n - __front_spare());
1894    // __n <= __front_spare()
1895    __annotate_increase_front(__n);
1896    iterator __old_begin = begin();
1897    iterator __i         = __old_begin;
1898    _BiIter __m          = __f;
1899    if (__n > __pos) {
1900      __m = __pos < __n / 2 ? std::prev(__l, __pos) : std::next(__f, __n - __pos);
1901      for (_BiIter __j = __m; __j != __f; --__start_, ++__size())
1902        __alloc_traits::construct(__a, std::addressof(*--__i), *--__j);
1903      __n = __pos;
1904    }
1905    if (__n > 0) {
1906      iterator __obn = __old_begin + __n;
1907      for (iterator __j = __obn; __j != __old_begin;) {
1908        __alloc_traits::construct(__a, std::addressof(*--__i), std::move(*--__j));
1909        --__start_;
1910        ++__size();
1911      }
1912      if (__n < __pos)
1913        __old_begin = std::move(__obn, __old_begin + __pos, __old_begin);
1914      std::copy(__m, __l, __old_begin);
1915    }
1916  } else { // insert by shifting things forward
1917    size_type __back_capacity = __back_spare();
1918    if (__n > __back_capacity)
1919      __add_back_capacity(__n - __back_capacity);
1920    // __n <= __back_capacity
1921    __annotate_increase_back(__n);
1922    iterator __old_end = end();
1923    iterator __i       = __old_end;
1924    _BiIter __m        = __l;
1925    size_type __de     = size() - __pos;
1926    if (__n > __de) {
1927      __m = __de < __n / 2 ? std::next(__f, __de) : std::prev(__l, __n - __de);
1928      for (_BiIter __j = __m; __j != __l; ++__i, (void)++__j, ++__size())
1929        __alloc_traits::construct(__a, std::addressof(*__i), *__j);
1930      __n = __de;
1931    }
1932    if (__n > 0) {
1933      iterator __oen = __old_end - __n;
1934      for (iterator __j = __oen; __j != __old_end; ++__i, (void)++__j, ++__size())
1935        __alloc_traits::construct(__a, std::addressof(*__i), std::move(*__j));
1936      if (__n < __de)
1937        __old_end = std::move_backward(__old_end - __de, __oen, __old_end);
1938      std::copy_backward(__f, __m, __old_end);
1939    }
1940  }
1941  return begin() + __pos;
1942}
1943
1944template <class _Tp, class _Allocator>
1945template <class _InpIter, __enable_if_t<__has_exactly_input_iterator_category<_InpIter>::value, int> >
1946void deque<_Tp, _Allocator>::__append(_InpIter __f, _InpIter __l) {
1947  __append_with_sentinel(__f, __l);
1948}
1949
1950template <class _Tp, class _Allocator>
1951template <class _InputIterator, class _Sentinel>
1952_LIBCPP_HIDE_FROM_ABI void deque<_Tp, _Allocator>::__append_with_sentinel(_InputIterator __f, _Sentinel __l) {
1953  for (; __f != __l; ++__f)
1954#ifdef _LIBCPP_CXX03_LANG
1955    push_back(*__f);
1956#else
1957    emplace_back(*__f);
1958#endif
1959}
1960
1961template <class _Tp, class _Allocator>
1962template <class _ForIter, __enable_if_t<__has_forward_iterator_category<_ForIter>::value, int> >
1963void deque<_Tp, _Allocator>::__append(_ForIter __f, _ForIter __l) {
1964  __append_with_size(__f, std::distance(__f, __l));
1965}
1966
1967template <class _Tp, class _Allocator>
1968template <class _InputIterator>
1969_LIBCPP_HIDE_FROM_ABI void deque<_Tp, _Allocator>::__append_with_size(_InputIterator __f, size_type __n) {
1970  allocator_type& __a       = __alloc();
1971  size_type __back_capacity = __back_spare();
1972  if (__n > __back_capacity)
1973    __add_back_capacity(__n - __back_capacity);
1974
1975  // __n <= __back_capacity
1976  __annotate_increase_back(__n);
1977  for (__deque_block_range __br : __deque_range(end(), end() + __n)) {
1978    _ConstructTransaction __tx(this, __br);
1979    for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_, (void)++__f) {
1980      __alloc_traits::construct(__a, std::__to_address(__tx.__pos_), *__f);
1981    }
1982  }
1983}
1984
1985template <class _Tp, class _Allocator>
1986void deque<_Tp, _Allocator>::__append(size_type __n) {
1987  allocator_type& __a       = __alloc();
1988  size_type __back_capacity = __back_spare();
1989  if (__n > __back_capacity)
1990    __add_back_capacity(__n - __back_capacity);
1991  // __n <= __back_capacity
1992  __annotate_increase_back(__n);
1993  for (__deque_block_range __br : __deque_range(end(), end() + __n)) {
1994    _ConstructTransaction __tx(this, __br);
1995    for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_) {
1996      __alloc_traits::construct(__a, std::__to_address(__tx.__pos_));
1997    }
1998  }
1999}
2000
2001template <class _Tp, class _Allocator>
2002void deque<_Tp, _Allocator>::__append(size_type __n, const value_type& __v) {
2003  allocator_type& __a       = __alloc();
2004  size_type __back_capacity = __back_spare();
2005  if (__n > __back_capacity)
2006    __add_back_capacity(__n - __back_capacity);
2007  // __n <= __back_capacity
2008  __annotate_increase_back(__n);
2009  for (__deque_block_range __br : __deque_range(end(), end() + __n)) {
2010    _ConstructTransaction __tx(this, __br);
2011    for (; __tx.__pos_ != __tx.__end_; ++__tx.__pos_) {
2012      __alloc_traits::construct(__a, std::__to_address(__tx.__pos_), __v);
2013    }
2014  }
2015}
2016
2017// Create front capacity for one block of elements.
2018// Strong guarantee.  Either do it or don't touch anything.
2019template <class _Tp, class _Allocator>
2020void deque<_Tp, _Allocator>::__add_front_capacity() {
2021  allocator_type& __a = __alloc();
2022  if (__back_spare() >= __block_size) {
2023    __start_ += __block_size;
2024    pointer __pt = __map_.back();
2025    __map_.pop_back();
2026    __map_.push_front(__pt);
2027  }
2028  // Else if __map_.size() < __map_.capacity() then we need to allocate 1 buffer
2029  else if (__map_.size() < __map_.capacity()) { // we can put the new buffer into the map, but don't shift things around
2030    // until all buffers are allocated.  If we throw, we don't need to fix
2031    // anything up (any added buffers are undetectible)
2032    if (__map_.__front_spare() > 0)
2033      __map_.push_front(__alloc_traits::allocate(__a, __block_size));
2034    else {
2035      __map_.push_back(__alloc_traits::allocate(__a, __block_size));
2036      // Done allocating, reorder capacity
2037      pointer __pt = __map_.back();
2038      __map_.pop_back();
2039      __map_.push_front(__pt);
2040    }
2041    __start_ = __map_.size() == 1 ? __block_size / 2 : __start_ + __block_size;
2042  }
2043  // Else need to allocate 1 buffer, *and* we need to reallocate __map_.
2044  else {
2045    __split_buffer<pointer, __pointer_allocator&> __buf(
2046        std::max<size_type>(2 * __map_.capacity(), 1), 0, __map_.__alloc());
2047
2048    typedef __allocator_destructor<_Allocator> _Dp;
2049    unique_ptr<pointer, _Dp> __hold(__alloc_traits::allocate(__a, __block_size), _Dp(__a, __block_size));
2050    __buf.push_back(__hold.get());
2051    __hold.release();
2052
2053    for (__map_pointer __i = __map_.begin(); __i != __map_.end(); ++__i)
2054      __buf.push_back(*__i);
2055    std::swap(__map_.__first_, __buf.__first_);
2056    std::swap(__map_.__begin_, __buf.__begin_);
2057    std::swap(__map_.__end_, __buf.__end_);
2058    std::swap(__map_.__end_cap(), __buf.__end_cap());
2059    __start_ = __map_.size() == 1 ? __block_size / 2 : __start_ + __block_size;
2060  }
2061  __annotate_whole_block(0, __asan_poison);
2062}
2063
2064// Create front capacity for __n elements.
2065// Strong guarantee.  Either do it or don't touch anything.
2066template <class _Tp, class _Allocator>
2067void deque<_Tp, _Allocator>::__add_front_capacity(size_type __n) {
2068  allocator_type& __a = __alloc();
2069  size_type __nb      = __recommend_blocks(__n + __map_.empty());
2070  // Number of unused blocks at back:
2071  size_type __back_capacity = __back_spare() / __block_size;
2072  __back_capacity           = std::min(__back_capacity, __nb); // don't take more than you need
2073  __nb -= __back_capacity;                                     // number of blocks need to allocate
2074  // If __nb == 0, then we have sufficient capacity.
2075  if (__nb == 0) {
2076    __start_ += __block_size * __back_capacity;
2077    for (; __back_capacity > 0; --__back_capacity) {
2078      pointer __pt = __map_.back();
2079      __map_.pop_back();
2080      __map_.push_front(__pt);
2081    }
2082  }
2083  // Else if __nb <= __map_.capacity() - __map_.size() then we need to allocate __nb buffers
2084  else if (__nb <= __map_.capacity() -
2085                       __map_.size()) { // we can put the new buffers into the map, but don't shift things around
2086    // until all buffers are allocated.  If we throw, we don't need to fix
2087    // anything up (any added buffers are undetectible)
2088    for (; __nb > 0; --__nb, __start_ += __block_size - (__map_.size() == 1)) {
2089      if (__map_.__front_spare() == 0)
2090        break;
2091      __map_.push_front(__alloc_traits::allocate(__a, __block_size));
2092      __annotate_whole_block(0, __asan_poison);
2093    }
2094    for (; __nb > 0; --__nb, ++__back_capacity)
2095      __map_.push_back(__alloc_traits::allocate(__a, __block_size));
2096    // Done allocating, reorder capacity
2097    __start_ += __back_capacity * __block_size;
2098    for (; __back_capacity > 0; --__back_capacity) {
2099      pointer __pt = __map_.back();
2100      __map_.pop_back();
2101      __map_.push_front(__pt);
2102      __annotate_whole_block(0, __asan_poison);
2103    }
2104  }
2105  // Else need to allocate __nb buffers, *and* we need to reallocate __map_.
2106  else {
2107    size_type __ds = (__nb + __back_capacity) * __block_size - __map_.empty();
2108    __split_buffer<pointer, __pointer_allocator&> __buf(
2109        std::max<size_type>(2 * __map_.capacity(), __nb + __map_.size()), 0, __map_.__alloc());
2110#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
2111    try {
2112#endif // _LIBCPP_HAS_NO_EXCEPTIONS
2113      for (; __nb > 0; --__nb) {
2114        __buf.push_back(__alloc_traits::allocate(__a, __block_size));
2115        // ASan: this is empty container, we have to poison whole block
2116        __annotate_poison_block(std::__to_address(__buf.back()), std::__to_address(__buf.back() + __block_size));
2117      }
2118#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
2119    } catch (...) {
2120      __annotate_delete();
2121      for (__map_pointer __i = __buf.begin(); __i != __buf.end(); ++__i)
2122        __alloc_traits::deallocate(__a, *__i, __block_size);
2123      throw;
2124    }
2125#endif // _LIBCPP_HAS_NO_EXCEPTIONS
2126    for (; __back_capacity > 0; --__back_capacity) {
2127      __buf.push_back(__map_.back());
2128      __map_.pop_back();
2129    }
2130    for (__map_pointer __i = __map_.begin(); __i != __map_.end(); ++__i)
2131      __buf.push_back(*__i);
2132    std::swap(__map_.__first_, __buf.__first_);
2133    std::swap(__map_.__begin_, __buf.__begin_);
2134    std::swap(__map_.__end_, __buf.__end_);
2135    std::swap(__map_.__end_cap(), __buf.__end_cap());
2136    __start_ += __ds;
2137  }
2138}
2139
2140// Create back capacity for one block of elements.
2141// Strong guarantee.  Either do it or don't touch anything.
2142template <class _Tp, class _Allocator>
2143void deque<_Tp, _Allocator>::__add_back_capacity() {
2144  allocator_type& __a = __alloc();
2145  if (__front_spare() >= __block_size) {
2146    __start_ -= __block_size;
2147    pointer __pt = __map_.front();
2148    __map_.pop_front();
2149    __map_.push_back(__pt);
2150  }
2151  // Else if __nb <= __map_.capacity() - __map_.size() then we need to allocate __nb buffers
2152  else if (__map_.size() < __map_.capacity()) { // we can put the new buffer into the map, but don't shift things around
2153    // until it is allocated.  If we throw, we don't need to fix
2154    // anything up (any added buffers are undetectible)
2155    if (__map_.__back_spare() != 0)
2156      __map_.push_back(__alloc_traits::allocate(__a, __block_size));
2157    else {
2158      __map_.push_front(__alloc_traits::allocate(__a, __block_size));
2159      // Done allocating, reorder capacity
2160      pointer __pt = __map_.front();
2161      __map_.pop_front();
2162      __map_.push_back(__pt);
2163    }
2164    __annotate_whole_block(__map_.size() - 1, __asan_poison);
2165  }
2166  // Else need to allocate 1 buffer, *and* we need to reallocate __map_.
2167  else {
2168    __split_buffer<pointer, __pointer_allocator&> __buf(
2169        std::max<size_type>(2 * __map_.capacity(), 1), __map_.size(), __map_.__alloc());
2170
2171    typedef __allocator_destructor<_Allocator> _Dp;
2172    unique_ptr<pointer, _Dp> __hold(__alloc_traits::allocate(__a, __block_size), _Dp(__a, __block_size));
2173    __buf.push_back(__hold.get());
2174    __hold.release();
2175
2176    for (__map_pointer __i = __map_.end(); __i != __map_.begin();)
2177      __buf.push_front(*--__i);
2178    std::swap(__map_.__first_, __buf.__first_);
2179    std::swap(__map_.__begin_, __buf.__begin_);
2180    std::swap(__map_.__end_, __buf.__end_);
2181    std::swap(__map_.__end_cap(), __buf.__end_cap());
2182    __annotate_whole_block(__map_.size() - 1, __asan_poison);
2183  }
2184}
2185
2186// Create back capacity for __n elements.
2187// Strong guarantee.  Either do it or don't touch anything.
2188template <class _Tp, class _Allocator>
2189void deque<_Tp, _Allocator>::__add_back_capacity(size_type __n) {
2190  allocator_type& __a = __alloc();
2191  size_type __nb      = __recommend_blocks(__n + __map_.empty());
2192  // Number of unused blocks at front:
2193  size_type __front_capacity = __front_spare() / __block_size;
2194  __front_capacity           = std::min(__front_capacity, __nb); // don't take more than you need
2195  __nb -= __front_capacity;                                      // number of blocks need to allocate
2196  // If __nb == 0, then we have sufficient capacity.
2197  if (__nb == 0) {
2198    __start_ -= __block_size * __front_capacity;
2199    for (; __front_capacity > 0; --__front_capacity) {
2200      pointer __pt = __map_.front();
2201      __map_.pop_front();
2202      __map_.push_back(__pt);
2203    }
2204  }
2205  // Else if __nb <= __map_.capacity() - __map_.size() then we need to allocate __nb buffers
2206  else if (__nb <= __map_.capacity() -
2207                       __map_.size()) { // we can put the new buffers into the map, but don't shift things around
2208    // until all buffers are allocated.  If we throw, we don't need to fix
2209    // anything up (any added buffers are undetectible)
2210    for (; __nb > 0; --__nb) {
2211      if (__map_.__back_spare() == 0)
2212        break;
2213      __map_.push_back(__alloc_traits::allocate(__a, __block_size));
2214      __annotate_whole_block(__map_.size() - 1, __asan_poison);
2215    }
2216    for (; __nb > 0; --__nb, ++__front_capacity, __start_ += __block_size - (__map_.size() == 1)) {
2217      __map_.push_front(__alloc_traits::allocate(__a, __block_size));
2218      __annotate_whole_block(0, __asan_poison);
2219    }
2220    // Done allocating, reorder capacity
2221    __start_ -= __block_size * __front_capacity;
2222    for (; __front_capacity > 0; --__front_capacity) {
2223      pointer __pt = __map_.front();
2224      __map_.pop_front();
2225      __map_.push_back(__pt);
2226    }
2227  }
2228  // Else need to allocate __nb buffers, *and* we need to reallocate __map_.
2229  else {
2230    size_type __ds = __front_capacity * __block_size;
2231    __split_buffer<pointer, __pointer_allocator&> __buf(
2232        std::max<size_type>(2 * __map_.capacity(), __nb + __map_.size()),
2233        __map_.size() - __front_capacity,
2234        __map_.__alloc());
2235#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
2236    try {
2237#endif // _LIBCPP_HAS_NO_EXCEPTIONS
2238      for (; __nb > 0; --__nb) {
2239        __buf.push_back(__alloc_traits::allocate(__a, __block_size));
2240        // ASan: this is an empty container, we have to poison the whole block
2241        __annotate_poison_block(std::__to_address(__buf.back()), std::__to_address(__buf.back() + __block_size));
2242      }
2243#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
2244    } catch (...) {
2245      __annotate_delete();
2246      for (__map_pointer __i = __buf.begin(); __i != __buf.end(); ++__i)
2247        __alloc_traits::deallocate(__a, *__i, __block_size);
2248      throw;
2249    }
2250#endif // _LIBCPP_HAS_NO_EXCEPTIONS
2251    for (; __front_capacity > 0; --__front_capacity) {
2252      __buf.push_back(__map_.front());
2253      __map_.pop_front();
2254    }
2255    for (__map_pointer __i = __map_.end(); __i != __map_.begin();)
2256      __buf.push_front(*--__i);
2257    std::swap(__map_.__first_, __buf.__first_);
2258    std::swap(__map_.__begin_, __buf.__begin_);
2259    std::swap(__map_.__end_, __buf.__end_);
2260    std::swap(__map_.__end_cap(), __buf.__end_cap());
2261    __start_ -= __ds;
2262  }
2263}
2264
2265template <class _Tp, class _Allocator>
2266void deque<_Tp, _Allocator>::pop_front() {
2267  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "deque::pop_front called on an empty deque");
2268  size_type __old_sz    = size();
2269  size_type __old_start = __start_;
2270  allocator_type& __a   = __alloc();
2271  __alloc_traits::destroy(
2272      __a, std::__to_address(*(__map_.begin() + __start_ / __block_size) + __start_ % __block_size));
2273  --__size();
2274  ++__start_;
2275  __annotate_shrink_front(__old_sz, __old_start);
2276  __maybe_remove_front_spare();
2277}
2278
2279template <class _Tp, class _Allocator>
2280void deque<_Tp, _Allocator>::pop_back() {
2281  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "deque::pop_back called on an empty deque");
2282  size_type __old_sz    = size();
2283  size_type __old_start = __start_;
2284  allocator_type& __a   = __alloc();
2285  size_type __p         = size() + __start_ - 1;
2286  __alloc_traits::destroy(__a, std::__to_address(*(__map_.begin() + __p / __block_size) + __p % __block_size));
2287  --__size();
2288  __annotate_shrink_back(__old_sz, __old_start);
2289  __maybe_remove_back_spare();
2290}
2291
2292// move assign [__f, __l) to [__r, __r + (__l-__f)).
2293// If __vt points into [__f, __l), then subtract (__f - __r) from __vt.
2294template <class _Tp, class _Allocator>
2295typename deque<_Tp, _Allocator>::iterator
2296deque<_Tp, _Allocator>::__move_and_check(iterator __f, iterator __l, iterator __r, const_pointer& __vt) {
2297  // as if
2298  //   for (; __f != __l; ++__f, ++__r)
2299  //       *__r = std::move(*__f);
2300  difference_type __n = __l - __f;
2301  while (__n > 0) {
2302    pointer __fb         = __f.__ptr_;
2303    pointer __fe         = *__f.__m_iter_ + __block_size;
2304    difference_type __bs = __fe - __fb;
2305    if (__bs > __n) {
2306      __bs = __n;
2307      __fe = __fb + __bs;
2308    }
2309    if (__fb <= __vt && __vt < __fe)
2310      __vt = (const_iterator(static_cast<__map_const_pointer>(__f.__m_iter_), __vt) -= __f - __r).__ptr_;
2311    __r = std::move(__fb, __fe, __r);
2312    __n -= __bs;
2313    __f += __bs;
2314  }
2315  return __r;
2316}
2317
2318// move assign [__f, __l) to [__r - (__l-__f), __r) backwards.
2319// If __vt points into [__f, __l), then add (__r - __l) to __vt.
2320template <class _Tp, class _Allocator>
2321typename deque<_Tp, _Allocator>::iterator
2322deque<_Tp, _Allocator>::__move_backward_and_check(iterator __f, iterator __l, iterator __r, const_pointer& __vt) {
2323  // as if
2324  //   while (__f != __l)
2325  //       *--__r = std::move(*--__l);
2326  difference_type __n = __l - __f;
2327  while (__n > 0) {
2328    --__l;
2329    pointer __lb         = *__l.__m_iter_;
2330    pointer __le         = __l.__ptr_ + 1;
2331    difference_type __bs = __le - __lb;
2332    if (__bs > __n) {
2333      __bs = __n;
2334      __lb = __le - __bs;
2335    }
2336    if (__lb <= __vt && __vt < __le)
2337      __vt = (const_iterator(static_cast<__map_const_pointer>(__l.__m_iter_), __vt) += __r - __l - 1).__ptr_;
2338    __r = std::move_backward(__lb, __le, __r);
2339    __n -= __bs;
2340    __l -= __bs - 1;
2341  }
2342  return __r;
2343}
2344
2345// move construct [__f, __l) to [__r, __r + (__l-__f)).
2346// If __vt points into [__f, __l), then add (__r - __f) to __vt.
2347template <class _Tp, class _Allocator>
2348void deque<_Tp, _Allocator>::__move_construct_and_check(iterator __f, iterator __l, iterator __r, const_pointer& __vt) {
2349  allocator_type& __a = __alloc();
2350  // as if
2351  //   for (; __f != __l; ++__r, ++__f, ++__size())
2352  //       __alloc_traits::construct(__a, std::addressof(*__r), std::move(*__f));
2353  difference_type __n = __l - __f;
2354  while (__n > 0) {
2355    pointer __fb         = __f.__ptr_;
2356    pointer __fe         = *__f.__m_iter_ + __block_size;
2357    difference_type __bs = __fe - __fb;
2358    if (__bs > __n) {
2359      __bs = __n;
2360      __fe = __fb + __bs;
2361    }
2362    if (__fb <= __vt && __vt < __fe)
2363      __vt = (const_iterator(static_cast<__map_const_pointer>(__f.__m_iter_), __vt) += __r - __f).__ptr_;
2364    for (; __fb != __fe; ++__fb, ++__r, ++__size())
2365      __alloc_traits::construct(__a, std::addressof(*__r), std::move(*__fb));
2366    __n -= __bs;
2367    __f += __bs;
2368  }
2369}
2370
2371// move construct [__f, __l) to [__r - (__l-__f), __r) backwards.
2372// If __vt points into [__f, __l), then subtract (__l - __r) from __vt.
2373template <class _Tp, class _Allocator>
2374void deque<_Tp, _Allocator>::__move_construct_backward_and_check(
2375    iterator __f, iterator __l, iterator __r, const_pointer& __vt) {
2376  allocator_type& __a = __alloc();
2377  // as if
2378  //   for (iterator __j = __l; __j != __f;)
2379  //   {
2380  //       __alloc_traitsconstruct(__a, std::addressof(*--__r), std::move(*--__j));
2381  //       --__start_;
2382  //       ++__size();
2383  //   }
2384  difference_type __n = __l - __f;
2385  while (__n > 0) {
2386    --__l;
2387    pointer __lb         = *__l.__m_iter_;
2388    pointer __le         = __l.__ptr_ + 1;
2389    difference_type __bs = __le - __lb;
2390    if (__bs > __n) {
2391      __bs = __n;
2392      __lb = __le - __bs;
2393    }
2394    if (__lb <= __vt && __vt < __le)
2395      __vt = (const_iterator(static_cast<__map_const_pointer>(__l.__m_iter_), __vt) -= __l - __r + 1).__ptr_;
2396    while (__le != __lb) {
2397      __alloc_traits::construct(__a, std::addressof(*--__r), std::move(*--__le));
2398      --__start_;
2399      ++__size();
2400    }
2401    __n -= __bs;
2402    __l -= __bs - 1;
2403  }
2404}
2405
2406template <class _Tp, class _Allocator>
2407typename deque<_Tp, _Allocator>::iterator deque<_Tp, _Allocator>::erase(const_iterator __f) {
2408  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
2409      __f != end(), "deque::erase(iterator) called with a non-dereferenceable iterator");
2410  size_type __old_sz    = size();
2411  size_type __old_start = __start_;
2412  iterator __b          = begin();
2413  difference_type __pos = __f - __b;
2414  iterator __p          = __b + __pos;
2415  allocator_type& __a   = __alloc();
2416  if (static_cast<size_t>(__pos) <= (size() - 1) / 2) { // erase from front
2417    std::move_backward(__b, __p, std::next(__p));
2418    __alloc_traits::destroy(__a, std::addressof(*__b));
2419    --__size();
2420    ++__start_;
2421    __annotate_shrink_front(__old_sz, __old_start);
2422    __maybe_remove_front_spare();
2423  } else { // erase from back
2424    iterator __i = std::move(std::next(__p), end(), __p);
2425    __alloc_traits::destroy(__a, std::addressof(*__i));
2426    --__size();
2427    __annotate_shrink_back(__old_sz, __old_start);
2428    __maybe_remove_back_spare();
2429  }
2430  return begin() + __pos;
2431}
2432
2433template <class _Tp, class _Allocator>
2434typename deque<_Tp, _Allocator>::iterator deque<_Tp, _Allocator>::erase(const_iterator __f, const_iterator __l) {
2435  _LIBCPP_ASSERT_VALID_INPUT_RANGE(__f <= __l, "deque::erase(first, last) called with an invalid range");
2436  size_type __old_sz    = size();
2437  size_type __old_start = __start_;
2438  difference_type __n   = __l - __f;
2439  iterator __b          = begin();
2440  difference_type __pos = __f - __b;
2441  iterator __p          = __b + __pos;
2442  if (__n > 0) {
2443    allocator_type& __a = __alloc();
2444    if (static_cast<size_t>(__pos) <= (size() - __n) / 2) { // erase from front
2445      iterator __i = std::move_backward(__b, __p, __p + __n);
2446      for (; __b != __i; ++__b)
2447        __alloc_traits::destroy(__a, std::addressof(*__b));
2448      __size() -= __n;
2449      __start_ += __n;
2450      __annotate_shrink_front(__old_sz, __old_start);
2451      while (__maybe_remove_front_spare()) {
2452      }
2453    } else { // erase from back
2454      iterator __i = std::move(__p + __n, end(), __p);
2455      for (iterator __e = end(); __i != __e; ++__i)
2456        __alloc_traits::destroy(__a, std::addressof(*__i));
2457      __size() -= __n;
2458      __annotate_shrink_back(__old_sz, __old_start);
2459      while (__maybe_remove_back_spare()) {
2460      }
2461    }
2462  }
2463  return begin() + __pos;
2464}
2465
2466template <class _Tp, class _Allocator>
2467void deque<_Tp, _Allocator>::__erase_to_end(const_iterator __f) {
2468  size_type __old_sz    = size();
2469  size_type __old_start = __start_;
2470  iterator __e          = end();
2471  difference_type __n   = __e - __f;
2472  if (__n > 0) {
2473    allocator_type& __a   = __alloc();
2474    iterator __b          = begin();
2475    difference_type __pos = __f - __b;
2476    for (iterator __p = __b + __pos; __p != __e; ++__p)
2477      __alloc_traits::destroy(__a, std::addressof(*__p));
2478    __size() -= __n;
2479    __annotate_shrink_back(__old_sz, __old_start);
2480    while (__maybe_remove_back_spare()) {
2481    }
2482  }
2483}
2484
2485template <class _Tp, class _Allocator>
2486inline void deque<_Tp, _Allocator>::swap(deque& __c)
2487#if _LIBCPP_STD_VER >= 14
2488    _NOEXCEPT
2489#else
2490    _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value || __is_nothrow_swappable_v<allocator_type>)
2491#endif
2492{
2493  __map_.swap(__c.__map_);
2494  std::swap(__start_, __c.__start_);
2495  std::swap(__size(), __c.__size());
2496  std::__swap_allocator(__alloc(), __c.__alloc());
2497}
2498
2499template <class _Tp, class _Allocator>
2500inline void deque<_Tp, _Allocator>::clear() _NOEXCEPT {
2501  __annotate_delete();
2502  allocator_type& __a = __alloc();
2503  for (iterator __i = begin(), __e = end(); __i != __e; ++__i)
2504    __alloc_traits::destroy(__a, std::addressof(*__i));
2505  __size() = 0;
2506  while (__map_.size() > 2) {
2507    __alloc_traits::deallocate(__a, __map_.front(), __block_size);
2508    __map_.pop_front();
2509  }
2510  switch (__map_.size()) {
2511  case 1:
2512    __start_ = __block_size / 2;
2513    break;
2514  case 2:
2515    __start_ = __block_size;
2516    break;
2517  }
2518  __annotate_new(0);
2519}
2520
2521template <class _Tp, class _Allocator>
2522inline _LIBCPP_HIDE_FROM_ABI bool operator==(const deque<_Tp, _Allocator>& __x, const deque<_Tp, _Allocator>& __y) {
2523  const typename deque<_Tp, _Allocator>::size_type __sz = __x.size();
2524  return __sz == __y.size() && std::equal(__x.begin(), __x.end(), __y.begin());
2525}
2526
2527#if _LIBCPP_STD_VER <= 17
2528
2529template <class _Tp, class _Allocator>
2530inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const deque<_Tp, _Allocator>& __x, const deque<_Tp, _Allocator>& __y) {
2531  return !(__x == __y);
2532}
2533
2534template <class _Tp, class _Allocator>
2535inline _LIBCPP_HIDE_FROM_ABI bool operator<(const deque<_Tp, _Allocator>& __x, const deque<_Tp, _Allocator>& __y) {
2536  return std::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
2537}
2538
2539template <class _Tp, class _Allocator>
2540inline _LIBCPP_HIDE_FROM_ABI bool operator>(const deque<_Tp, _Allocator>& __x, const deque<_Tp, _Allocator>& __y) {
2541  return __y < __x;
2542}
2543
2544template <class _Tp, class _Allocator>
2545inline _LIBCPP_HIDE_FROM_ABI bool operator>=(const deque<_Tp, _Allocator>& __x, const deque<_Tp, _Allocator>& __y) {
2546  return !(__x < __y);
2547}
2548
2549template <class _Tp, class _Allocator>
2550inline _LIBCPP_HIDE_FROM_ABI bool operator<=(const deque<_Tp, _Allocator>& __x, const deque<_Tp, _Allocator>& __y) {
2551  return !(__y < __x);
2552}
2553
2554#else // _LIBCPP_STD_VER <= 17
2555
2556template <class _Tp, class _Allocator>
2557_LIBCPP_HIDE_FROM_ABI __synth_three_way_result<_Tp>
2558operator<=>(const deque<_Tp, _Allocator>& __x, const deque<_Tp, _Allocator>& __y) {
2559  return std::lexicographical_compare_three_way(__x.begin(), __x.end(), __y.begin(), __y.end(), std::__synth_three_way);
2560}
2561
2562#endif // _LIBCPP_STD_VER <= 17
2563
2564template <class _Tp, class _Allocator>
2565inline _LIBCPP_HIDE_FROM_ABI void swap(deque<_Tp, _Allocator>& __x, deque<_Tp, _Allocator>& __y)
2566    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
2567  __x.swap(__y);
2568}
2569
2570#if _LIBCPP_STD_VER >= 20
2571template <class _Tp, class _Allocator, class _Up>
2572inline _LIBCPP_HIDE_FROM_ABI typename deque<_Tp, _Allocator>::size_type
2573erase(deque<_Tp, _Allocator>& __c, const _Up& __v) {
2574  auto __old_size = __c.size();
2575  __c.erase(std::remove(__c.begin(), __c.end(), __v), __c.end());
2576  return __old_size - __c.size();
2577}
2578
2579template <class _Tp, class _Allocator, class _Predicate>
2580inline _LIBCPP_HIDE_FROM_ABI typename deque<_Tp, _Allocator>::size_type
2581erase_if(deque<_Tp, _Allocator>& __c, _Predicate __pred) {
2582  auto __old_size = __c.size();
2583  __c.erase(std::remove_if(__c.begin(), __c.end(), __pred), __c.end());
2584  return __old_size - __c.size();
2585}
2586
2587template <>
2588inline constexpr bool __format::__enable_insertable<std::deque<char>> = true;
2589#  ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
2590template <>
2591inline constexpr bool __format::__enable_insertable<std::deque<wchar_t>> = true;
2592#  endif
2593
2594#endif // _LIBCPP_STD_VER >= 20
2595
2596_LIBCPP_END_NAMESPACE_STD
2597
2598#if _LIBCPP_STD_VER >= 17
2599_LIBCPP_BEGIN_NAMESPACE_STD
2600namespace pmr {
2601template <class _ValueT>
2602using deque _LIBCPP_AVAILABILITY_PMR = std::deque<_ValueT, polymorphic_allocator<_ValueT>>;
2603} // namespace pmr
2604_LIBCPP_END_NAMESPACE_STD
2605#endif
2606
2607_LIBCPP_POP_MACROS
2608
2609#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
2610#  include <algorithm>
2611#  include <atomic>
2612#  include <concepts>
2613#  include <cstdlib>
2614#  include <functional>
2615#  include <iosfwd>
2616#  include <iterator>
2617#  include <type_traits>
2618#  include <typeinfo>
2619#endif
2620
2621#endif // _LIBCPP_DEQUE
2622