xref: /llvm-project/libcxx/include/list (revision b9a2658a3e8bd13b0f9e7a8a440832a95b377216)
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_LIST
11#define _LIBCPP_LIST
12
13/*
14    list synopsis
15
16namespace std
17{
18
19template <class T, class Alloc = allocator<T> >
20class list
21{
22public:
23
24    // types:
25    typedef T value_type;
26    typedef Alloc allocator_type;
27    typedef typename allocator_type::reference reference;
28    typedef typename allocator_type::const_reference const_reference;
29    typedef typename allocator_type::pointer pointer;
30    typedef typename allocator_type::const_pointer const_pointer;
31    typedef implementation-defined iterator;
32    typedef implementation-defined const_iterator;
33    typedef implementation-defined size_type;
34    typedef implementation-defined difference_type;
35    typedef reverse_iterator<iterator> reverse_iterator;
36    typedef reverse_iterator<const_iterator> const_reverse_iterator;
37
38    list()
39        noexcept(is_nothrow_default_constructible<allocator_type>::value);
40    explicit list(const allocator_type& a);
41    explicit list(size_type n);
42    explicit list(size_type n, const allocator_type& a); // C++14
43    list(size_type n, const value_type& value);
44    list(size_type n, const value_type& value, const allocator_type& a);
45    template <class Iter>
46        list(Iter first, Iter last);
47    template <class Iter>
48        list(Iter first, Iter last, const allocator_type& a);
49    template<container-compatible-range<T> R>
50      list(from_range_t, R&& rg, const Allocator& = Allocator()); // C++23
51    list(const list& x);
52    list(const list&, const allocator_type& a);
53    list(list&& x)
54        noexcept(is_nothrow_move_constructible<allocator_type>::value);
55    list(list&&, const allocator_type& a);
56    list(initializer_list<value_type>);
57    list(initializer_list<value_type>, const allocator_type& a);
58
59    ~list();
60
61    list& operator=(const list& x);
62    list& operator=(list&& x)
63        noexcept(
64             allocator_type::propagate_on_container_move_assignment::value &&
65             is_nothrow_move_assignable<allocator_type>::value);
66    list& operator=(initializer_list<value_type>);
67    template <class Iter>
68        void assign(Iter first, Iter last);
69    template<container-compatible-range<T> R>
70      void assign_range(R&& rg); // C++23
71    void assign(size_type n, const value_type& t);
72    void assign(initializer_list<value_type>);
73
74    allocator_type get_allocator() const noexcept;
75
76    iterator begin() noexcept;
77    const_iterator begin() const noexcept;
78    iterator end() noexcept;
79    const_iterator end() const noexcept;
80    reverse_iterator rbegin() noexcept;
81    const_reverse_iterator rbegin() const noexcept;
82    reverse_iterator rend() noexcept;
83    const_reverse_iterator rend() const noexcept;
84    const_iterator cbegin() const noexcept;
85    const_iterator cend() const noexcept;
86    const_reverse_iterator crbegin() const noexcept;
87    const_reverse_iterator crend() const noexcept;
88
89    reference front();
90    const_reference front() const;
91    reference back();
92    const_reference back() const;
93
94    bool empty() const noexcept;
95    size_type size() const noexcept;
96    size_type max_size() const noexcept;
97
98    template <class... Args>
99        reference emplace_front(Args&&... args); // reference in C++17
100    void pop_front();
101    template <class... Args>
102        reference emplace_back(Args&&... args);  // reference in C++17
103    void pop_back();
104    void push_front(const value_type& x);
105    void push_front(value_type&& x);
106    template<container-compatible-range<T> R>
107      void prepend_range(R&& rg); // C++23
108    void push_back(const value_type& x);
109    void push_back(value_type&& x);
110    template<container-compatible-range<T> R>
111      void append_range(R&& rg); // C++23
112    template <class... Args>
113        iterator emplace(const_iterator position, Args&&... args);
114    iterator insert(const_iterator position, const value_type& x);
115    iterator insert(const_iterator position, value_type&& x);
116    iterator insert(const_iterator position, size_type n, const value_type& x);
117    template <class Iter>
118        iterator insert(const_iterator position, Iter first, Iter last);
119    template<container-compatible-range<T> R>
120      iterator insert_range(const_iterator position, R&& rg); // C++23
121    iterator insert(const_iterator position, initializer_list<value_type> il);
122
123    iterator erase(const_iterator position);
124    iterator erase(const_iterator position, const_iterator last);
125
126    void resize(size_type sz);
127    void resize(size_type sz, const value_type& c);
128
129    void swap(list&)
130        noexcept(allocator_traits<allocator_type>::is_always_equal::value);  // C++17
131    void clear() noexcept;
132
133    void splice(const_iterator position, list& x);
134    void splice(const_iterator position, list&& x);
135    void splice(const_iterator position, list& x, const_iterator i);
136    void splice(const_iterator position, list&& x, const_iterator i);
137    void splice(const_iterator position, list& x, const_iterator first,
138                                                  const_iterator last);
139    void splice(const_iterator position, list&& x, const_iterator first,
140                                                  const_iterator last);
141
142    size_type remove(const value_type& value);       // void before C++20
143    template <class Pred>
144      size_type remove_if(Pred pred);                // void before C++20
145    size_type unique();                              // void before C++20
146    template <class BinaryPredicate>
147      size_type unique(BinaryPredicate binary_pred); // void before C++20
148    void merge(list& x);
149    void merge(list&& x);
150    template <class Compare>
151        void merge(list& x, Compare comp);
152    template <class Compare>
153        void merge(list&& x, Compare comp);
154    void sort();
155    template <class Compare>
156        void sort(Compare comp);
157    void reverse() noexcept;
158};
159
160
161template <class InputIterator, class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
162    list(InputIterator, InputIterator, Allocator = Allocator())
163    -> list<typename iterator_traits<InputIterator>::value_type, Allocator>;  // C++17
164
165template<ranges::input_range R, class Allocator = allocator<ranges::range_value_t<R>>>
166  list(from_range_t, R&&, Allocator = Allocator())
167    -> list<ranges::range_value_t<R>, Allocator>; // C++23
168
169template <class T, class Alloc>
170    bool operator==(const list<T,Alloc>& x, const list<T,Alloc>& y);
171template <class T, class Alloc>
172    bool operator< (const list<T,Alloc>& x, const list<T,Alloc>& y);     // removed in C++20
173template <class T, class Alloc>
174    bool operator!=(const list<T,Alloc>& x, const list<T,Alloc>& y);     // removed in C++20
175template <class T, class Alloc>
176    bool operator> (const list<T,Alloc>& x, const list<T,Alloc>& y);     // removed in C++20
177template <class T, class Alloc>
178    bool operator>=(const list<T,Alloc>& x, const list<T,Alloc>& y);     // removed in C++20
179template <class T, class Alloc>
180    bool operator<=(const list<T,Alloc>& x, const list<T,Alloc>& y);     // removed in C++20
181template<class T, class Allocator>
182  synth-three-way-result<T> operator<=>(const list<T, Allocator>& x,
183                                        const list<T, Allocator>& y);    // since C++20
184
185template <class T, class Alloc>
186    void swap(list<T,Alloc>& x, list<T,Alloc>& y)
187         noexcept(noexcept(x.swap(y)));
188
189template <class T, class Allocator, class U>
190    typename list<T, Allocator>::size_type
191    erase(list<T, Allocator>& c, const U& value);       // since C++20
192template <class T, class Allocator, class Predicate>
193    typename list<T, Allocator>::size_type
194    erase_if(list<T, Allocator>& c, Predicate pred);    // since C++20
195
196}  // std
197
198*/
199
200#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
201#  include <__cxx03/list>
202#else
203#  include <__algorithm/comp.h>
204#  include <__algorithm/equal.h>
205#  include <__algorithm/lexicographical_compare.h>
206#  include <__algorithm/lexicographical_compare_three_way.h>
207#  include <__algorithm/min.h>
208#  include <__assert>
209#  include <__config>
210#  include <__format/enable_insertable.h>
211#  include <__iterator/distance.h>
212#  include <__iterator/iterator_traits.h>
213#  include <__iterator/move_iterator.h>
214#  include <__iterator/next.h>
215#  include <__iterator/prev.h>
216#  include <__iterator/reverse_iterator.h>
217#  include <__memory/addressof.h>
218#  include <__memory/allocation_guard.h>
219#  include <__memory/allocator.h>
220#  include <__memory/allocator_traits.h>
221#  include <__memory/compressed_pair.h>
222#  include <__memory/construct_at.h>
223#  include <__memory/pointer_traits.h>
224#  include <__memory/swap_allocator.h>
225#  include <__memory_resource/polymorphic_allocator.h>
226#  include <__new/launder.h>
227#  include <__ranges/access.h>
228#  include <__ranges/concepts.h>
229#  include <__ranges/container_compatible_range.h>
230#  include <__ranges/from_range.h>
231#  include <__type_traits/conditional.h>
232#  include <__type_traits/container_traits.h>
233#  include <__type_traits/enable_if.h>
234#  include <__type_traits/is_allocator.h>
235#  include <__type_traits/is_nothrow_assignable.h>
236#  include <__type_traits/is_nothrow_constructible.h>
237#  include <__type_traits/is_pointer.h>
238#  include <__type_traits/is_same.h>
239#  include <__type_traits/type_identity.h>
240#  include <__utility/forward.h>
241#  include <__utility/move.h>
242#  include <__utility/swap.h>
243#  include <cstring>
244#  include <limits>
245#  include <version>
246
247// standard-mandated includes
248
249// [iterator.range]
250#  include <__iterator/access.h>
251#  include <__iterator/data.h>
252#  include <__iterator/empty.h>
253#  include <__iterator/reverse_access.h>
254#  include <__iterator/size.h>
255
256// [list.syn]
257#  include <compare>
258#  include <initializer_list>
259
260#  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
261#    pragma GCC system_header
262#  endif
263
264_LIBCPP_PUSH_MACROS
265#  include <__undef_macros>
266
267_LIBCPP_BEGIN_NAMESPACE_STD
268
269template <class _Tp, class _VoidPtr>
270struct __list_node;
271template <class _Tp, class _VoidPtr>
272struct __list_node_base;
273
274template <class _Tp, class _VoidPtr>
275struct __list_node_pointer_traits {
276  typedef __rebind_pointer_t<_VoidPtr, __list_node<_Tp, _VoidPtr> > __node_pointer;
277  typedef __rebind_pointer_t<_VoidPtr, __list_node_base<_Tp, _VoidPtr> > __base_pointer;
278
279// TODO(LLVM 22): Remove this check
280#  ifndef _LIBCPP_ABI_LIST_REMOVE_NODE_POINTER_UB
281  static_assert(sizeof(__node_pointer) == sizeof(__node_pointer) && _LIBCPP_ALIGNOF(__base_pointer) ==
282                    _LIBCPP_ALIGNOF(__node_pointer),
283                "It looks like you are using std::list with a fancy pointer type that thas a different representation "
284                "depending on whether it points to a list base pointer or a list node pointer (both of which are "
285                "implementation details of the standard library). This means that your ABI is being broken between "
286                "LLVM 19 and LLVM 20. If you don't care about your ABI being broken, define the "
287                "_LIBCPP_ABI_LIST_REMOVE_NODE_POINTER_UB macro to silence this diagnostic.");
288#  endif
289
290  static _LIBCPP_HIDE_FROM_ABI __base_pointer __unsafe_link_pointer_cast(__base_pointer __p) { return __p; }
291
292  static _LIBCPP_HIDE_FROM_ABI __base_pointer __unsafe_link_pointer_cast(__node_pointer __p) {
293    return static_cast<__base_pointer>(static_cast<_VoidPtr>(__p));
294  }
295};
296
297template <class _Tp, class _VoidPtr>
298struct __list_node_base {
299  typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
300  typedef typename _NodeTraits::__node_pointer __node_pointer;
301  typedef typename _NodeTraits::__base_pointer __base_pointer;
302
303  __base_pointer __prev_;
304  __base_pointer __next_;
305
306  _LIBCPP_HIDE_FROM_ABI __list_node_base() : __prev_(__self()), __next_(__self()) {}
307
308  _LIBCPP_HIDE_FROM_ABI explicit __list_node_base(__base_pointer __prev, __base_pointer __next)
309      : __prev_(__prev), __next_(__next) {}
310
311  _LIBCPP_HIDE_FROM_ABI __base_pointer __self() { return pointer_traits<__base_pointer>::pointer_to(*this); }
312
313  _LIBCPP_HIDE_FROM_ABI __node_pointer __as_node() { return static_cast<__node_pointer>(__self()); }
314};
315
316template <class _Tp, class _VoidPtr>
317struct __list_node : public __list_node_base<_Tp, _VoidPtr> {
318  // We allow starting the lifetime of nodes without initializing the value held by the node,
319  // since that is handled by the list itself in order to be allocator-aware.
320#  ifndef _LIBCPP_CXX03_LANG
321
322private:
323  union {
324    _Tp __value_;
325  };
326
327public:
328  _LIBCPP_HIDE_FROM_ABI _Tp& __get_value() { return __value_; }
329#  else
330
331private:
332  _ALIGNAS_TYPE(_Tp) char __buffer_[sizeof(_Tp)];
333
334public:
335  _LIBCPP_HIDE_FROM_ABI _Tp& __get_value() { return *std::__launder(reinterpret_cast<_Tp*>(&__buffer_)); }
336#  endif
337
338  typedef __list_node_base<_Tp, _VoidPtr> __base;
339  typedef typename __base::__base_pointer __base_pointer;
340
341  _LIBCPP_HIDE_FROM_ABI explicit __list_node(__base_pointer __prev, __base_pointer __next) : __base(__prev, __next) {}
342  _LIBCPP_HIDE_FROM_ABI ~__list_node() {}
343
344  _LIBCPP_HIDE_FROM_ABI __base_pointer __as_link() { return __base::__self(); }
345};
346
347template <class _Tp, class _Alloc = allocator<_Tp> >
348class _LIBCPP_TEMPLATE_VIS list;
349template <class _Tp, class _Alloc>
350class __list_imp;
351template <class _Tp, class _VoidPtr>
352class _LIBCPP_TEMPLATE_VIS __list_const_iterator;
353
354template <class _Tp, class _VoidPtr>
355class _LIBCPP_TEMPLATE_VIS __list_iterator {
356  typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
357  typedef typename _NodeTraits::__base_pointer __base_pointer;
358
359  __base_pointer __ptr_;
360
361  _LIBCPP_HIDE_FROM_ABI explicit __list_iterator(__base_pointer __p) _NOEXCEPT : __ptr_(__p) {}
362
363  template <class, class>
364  friend class list;
365  template <class, class>
366  friend class __list_imp;
367  template <class, class>
368  friend class __list_const_iterator;
369
370public:
371  typedef bidirectional_iterator_tag iterator_category;
372  typedef _Tp value_type;
373  typedef value_type& reference;
374  typedef __rebind_pointer_t<_VoidPtr, value_type> pointer;
375  typedef typename pointer_traits<pointer>::difference_type difference_type;
376
377  _LIBCPP_HIDE_FROM_ABI __list_iterator() _NOEXCEPT : __ptr_(nullptr) {}
378
379  _LIBCPP_HIDE_FROM_ABI reference operator*() const { return __ptr_->__as_node()->__get_value(); }
380  _LIBCPP_HIDE_FROM_ABI pointer operator->() const {
381    return pointer_traits<pointer>::pointer_to(__ptr_->__as_node()->__get_value());
382  }
383
384  _LIBCPP_HIDE_FROM_ABI __list_iterator& operator++() {
385    __ptr_ = __ptr_->__next_;
386    return *this;
387  }
388  _LIBCPP_HIDE_FROM_ABI __list_iterator operator++(int) {
389    __list_iterator __t(*this);
390    ++(*this);
391    return __t;
392  }
393
394  _LIBCPP_HIDE_FROM_ABI __list_iterator& operator--() {
395    __ptr_ = __ptr_->__prev_;
396    return *this;
397  }
398  _LIBCPP_HIDE_FROM_ABI __list_iterator operator--(int) {
399    __list_iterator __t(*this);
400    --(*this);
401    return __t;
402  }
403
404  friend _LIBCPP_HIDE_FROM_ABI bool operator==(const __list_iterator& __x, const __list_iterator& __y) {
405    return __x.__ptr_ == __y.__ptr_;
406  }
407  friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const __list_iterator& __x, const __list_iterator& __y) {
408    return !(__x == __y);
409  }
410};
411
412template <class _Tp, class _VoidPtr>
413class _LIBCPP_TEMPLATE_VIS __list_const_iterator {
414  typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
415  typedef typename _NodeTraits::__base_pointer __base_pointer;
416
417  __base_pointer __ptr_;
418
419  _LIBCPP_HIDE_FROM_ABI explicit __list_const_iterator(__base_pointer __p) _NOEXCEPT : __ptr_(__p) {}
420
421  template <class, class>
422  friend class list;
423  template <class, class>
424  friend class __list_imp;
425
426public:
427  typedef bidirectional_iterator_tag iterator_category;
428  typedef _Tp value_type;
429  typedef const value_type& reference;
430  typedef __rebind_pointer_t<_VoidPtr, const value_type> pointer;
431  typedef typename pointer_traits<pointer>::difference_type difference_type;
432
433  _LIBCPP_HIDE_FROM_ABI __list_const_iterator() _NOEXCEPT : __ptr_(nullptr) {}
434  _LIBCPP_HIDE_FROM_ABI __list_const_iterator(const __list_iterator<_Tp, _VoidPtr>& __p) _NOEXCEPT
435      : __ptr_(__p.__ptr_) {}
436
437  _LIBCPP_HIDE_FROM_ABI reference operator*() const { return __ptr_->__as_node()->__get_value(); }
438  _LIBCPP_HIDE_FROM_ABI pointer operator->() const {
439    return pointer_traits<pointer>::pointer_to(__ptr_->__as_node()->__get_value());
440  }
441
442  _LIBCPP_HIDE_FROM_ABI __list_const_iterator& operator++() {
443    __ptr_ = __ptr_->__next_;
444    return *this;
445  }
446  _LIBCPP_HIDE_FROM_ABI __list_const_iterator operator++(int) {
447    __list_const_iterator __t(*this);
448    ++(*this);
449    return __t;
450  }
451
452  _LIBCPP_HIDE_FROM_ABI __list_const_iterator& operator--() {
453    __ptr_ = __ptr_->__prev_;
454    return *this;
455  }
456  _LIBCPP_HIDE_FROM_ABI __list_const_iterator operator--(int) {
457    __list_const_iterator __t(*this);
458    --(*this);
459    return __t;
460  }
461
462  friend _LIBCPP_HIDE_FROM_ABI bool operator==(const __list_const_iterator& __x, const __list_const_iterator& __y) {
463    return __x.__ptr_ == __y.__ptr_;
464  }
465  friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const __list_const_iterator& __x, const __list_const_iterator& __y) {
466    return !(__x == __y);
467  }
468};
469
470template <class _Tp, class _Alloc>
471class __list_imp {
472public:
473  __list_imp(const __list_imp&)            = delete;
474  __list_imp& operator=(const __list_imp&) = delete;
475
476  typedef _Alloc allocator_type;
477  typedef allocator_traits<allocator_type> __alloc_traits;
478  typedef typename __alloc_traits::size_type size_type;
479
480protected:
481  typedef _Tp value_type;
482  typedef typename __alloc_traits::void_pointer __void_pointer;
483  typedef __list_iterator<value_type, __void_pointer> iterator;
484  typedef __list_const_iterator<value_type, __void_pointer> const_iterator;
485  typedef __list_node_base<value_type, __void_pointer> __node_base;
486  typedef __list_node<value_type, __void_pointer> __node_type;
487  typedef __rebind_alloc<__alloc_traits, __node_type> __node_allocator;
488  typedef allocator_traits<__node_allocator> __node_alloc_traits;
489  typedef typename __node_alloc_traits::pointer __node_pointer;
490  typedef typename __node_alloc_traits::pointer __node_const_pointer;
491  typedef __list_node_pointer_traits<value_type, __void_pointer> __node_pointer_traits;
492  typedef typename __node_pointer_traits::__base_pointer __base_pointer;
493  typedef __base_pointer __link_const_pointer;
494  typedef typename __alloc_traits::pointer pointer;
495  typedef typename __alloc_traits::const_pointer const_pointer;
496  typedef typename __alloc_traits::difference_type difference_type;
497
498  typedef __rebind_alloc<__alloc_traits, __node_base> __node_base_allocator;
499  typedef typename allocator_traits<__node_base_allocator>::pointer __node_base_pointer;
500  static_assert(!is_same<allocator_type, __node_allocator>::value,
501                "internal allocator type must differ from user-specified type; otherwise overload resolution breaks");
502
503  __node_base __end_;
504  _LIBCPP_COMPRESSED_PAIR(size_type, __size_, __node_allocator, __node_alloc_);
505
506  _LIBCPP_HIDE_FROM_ABI __base_pointer __end_as_link() const _NOEXCEPT {
507    return __node_pointer_traits::__unsafe_link_pointer_cast(const_cast<__node_base&>(__end_).__self());
508  }
509
510  _LIBCPP_HIDE_FROM_ABI size_type __node_alloc_max_size() const _NOEXCEPT {
511    return __node_alloc_traits::max_size(__node_alloc_);
512  }
513  _LIBCPP_HIDE_FROM_ABI static void __unlink_nodes(__base_pointer __f, __base_pointer __l) _NOEXCEPT;
514
515  _LIBCPP_HIDE_FROM_ABI __list_imp() _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value);
516  _LIBCPP_HIDE_FROM_ABI __list_imp(const allocator_type& __a);
517  _LIBCPP_HIDE_FROM_ABI __list_imp(const __node_allocator& __a);
518#  ifndef _LIBCPP_CXX03_LANG
519  _LIBCPP_HIDE_FROM_ABI __list_imp(__node_allocator&& __a) _NOEXCEPT;
520#  endif
521  _LIBCPP_HIDE_FROM_ABI ~__list_imp();
522  _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT;
523  _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __size_ == 0; }
524
525  _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return iterator(__end_.__next_); }
526  _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return const_iterator(__end_.__next_); }
527  _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return iterator(__end_as_link()); }
528  _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return const_iterator(__end_as_link()); }
529
530  _LIBCPP_HIDE_FROM_ABI void swap(__list_imp& __c)
531#  if _LIBCPP_STD_VER >= 14
532      _NOEXCEPT;
533#  else
534      _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value || __is_nothrow_swappable_v<allocator_type>);
535#  endif
536
537  _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const __list_imp& __c) {
538    __copy_assign_alloc(
539        __c, integral_constant<bool, __node_alloc_traits::propagate_on_container_copy_assignment::value>());
540  }
541
542  _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__list_imp& __c)
543      _NOEXCEPT_(!__node_alloc_traits::propagate_on_container_move_assignment::value ||
544                 is_nothrow_move_assignable<__node_allocator>::value) {
545    __move_assign_alloc(
546        __c, integral_constant<bool, __node_alloc_traits::propagate_on_container_move_assignment::value>());
547  }
548
549  template <class... _Args>
550  _LIBCPP_HIDE_FROM_ABI __node_pointer __create_node(__base_pointer __prev, __base_pointer __next, _Args&&... __args) {
551    __allocation_guard<__node_allocator> __guard(__node_alloc_, 1);
552    // Begin the lifetime of the node itself. Note that this doesn't begin the lifetime of the value
553    // held inside the node, since we need to use the allocator's construct() method for that.
554    //
555    // We don't use the allocator's construct() method to construct the node itself since the
556    // Cpp17FooInsertable named requirements don't require the allocator's construct() method
557    // to work on anything other than the value_type.
558    std::__construct_at(std::addressof(*__guard.__get()), __prev, __next);
559
560    // Now construct the value_type using the allocator's construct() method.
561    __node_alloc_traits::construct(
562        __node_alloc_, std::addressof(__guard.__get()->__get_value()), std::forward<_Args>(__args)...);
563    return __guard.__release_ptr();
564  }
565
566  _LIBCPP_HIDE_FROM_ABI void __delete_node(__node_pointer __node) {
567    // For the same reason as above, we use the allocator's destroy() method for the value_type,
568    // but not for the node itself.
569    __node_alloc_traits::destroy(__node_alloc_, std::addressof(__node->__get_value()));
570    std::__destroy_at(std::addressof(*__node));
571    __node_alloc_traits::deallocate(__node_alloc_, __node, 1);
572  }
573
574private:
575  _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const __list_imp& __c, true_type) {
576    if (__node_alloc_ != __c.__node_alloc_)
577      clear();
578    __node_alloc_ = __c.__node_alloc_;
579  }
580
581  _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const __list_imp&, false_type) {}
582
583  _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__list_imp& __c, true_type)
584      _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value) {
585    __node_alloc_ = std::move(__c.__node_alloc_);
586  }
587
588  _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__list_imp&, false_type) _NOEXCEPT {}
589};
590
591// Unlink nodes [__f, __l]
592template <class _Tp, class _Alloc>
593inline void __list_imp<_Tp, _Alloc>::__unlink_nodes(__base_pointer __f, __base_pointer __l) _NOEXCEPT {
594  __f->__prev_->__next_ = __l->__next_;
595  __l->__next_->__prev_ = __f->__prev_;
596}
597
598template <class _Tp, class _Alloc>
599inline __list_imp<_Tp, _Alloc>::__list_imp() _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)
600    : __size_(0) {}
601
602template <class _Tp, class _Alloc>
603inline __list_imp<_Tp, _Alloc>::__list_imp(const allocator_type& __a)
604    : __size_(0), __node_alloc_(__node_allocator(__a)) {}
605
606template <class _Tp, class _Alloc>
607inline __list_imp<_Tp, _Alloc>::__list_imp(const __node_allocator& __a) : __size_(0), __node_alloc_(__a) {}
608
609#  ifndef _LIBCPP_CXX03_LANG
610template <class _Tp, class _Alloc>
611inline __list_imp<_Tp, _Alloc>::__list_imp(__node_allocator&& __a) _NOEXCEPT
612    : __size_(0),
613      __node_alloc_(std::move(__a)) {}
614#  endif
615
616template <class _Tp, class _Alloc>
617__list_imp<_Tp, _Alloc>::~__list_imp() {
618  clear();
619}
620
621template <class _Tp, class _Alloc>
622void __list_imp<_Tp, _Alloc>::clear() _NOEXCEPT {
623  if (!empty()) {
624    __base_pointer __f = __end_.__next_;
625    __base_pointer __l = __end_as_link();
626    __unlink_nodes(__f, __l->__prev_);
627    __size_ = 0;
628    while (__f != __l) {
629      __node_pointer __np = __f->__as_node();
630      __f                 = __f->__next_;
631      __delete_node(__np);
632    }
633  }
634}
635
636template <class _Tp, class _Alloc>
637void __list_imp<_Tp, _Alloc>::swap(__list_imp& __c)
638#  if _LIBCPP_STD_VER >= 14
639    _NOEXCEPT
640#  else
641    _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value || __is_nothrow_swappable_v<allocator_type>)
642#  endif
643{
644  _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
645      __alloc_traits::propagate_on_container_swap::value || this->__node_alloc_ == __c.__node_alloc_,
646      "list::swap: Either propagate_on_container_swap must be true"
647      " or the allocators must compare equal");
648  using std::swap;
649  std::__swap_allocator(__node_alloc_, __c.__node_alloc_);
650  swap(__size_, __c.__size_);
651  swap(__end_, __c.__end_);
652  if (__size_ == 0)
653    __end_.__next_ = __end_.__prev_ = __end_as_link();
654  else
655    __end_.__prev_->__next_ = __end_.__next_->__prev_ = __end_as_link();
656  if (__c.__size_ == 0)
657    __c.__end_.__next_ = __c.__end_.__prev_ = __c.__end_as_link();
658  else
659    __c.__end_.__prev_->__next_ = __c.__end_.__next_->__prev_ = __c.__end_as_link();
660}
661
662template <class _Tp, class _Alloc /*= allocator<_Tp>*/>
663class _LIBCPP_TEMPLATE_VIS list : private __list_imp<_Tp, _Alloc> {
664  typedef __list_imp<_Tp, _Alloc> __base;
665  typedef typename __base::__node_type __node_type;
666  typedef typename __base::__node_allocator __node_allocator;
667  typedef typename __base::__node_pointer __node_pointer;
668  typedef typename __base::__node_alloc_traits __node_alloc_traits;
669  typedef typename __base::__node_base __node_base;
670  typedef typename __base::__node_base_pointer __node_base_pointer;
671  typedef typename __base::__base_pointer __base_pointer;
672
673public:
674  typedef _Tp value_type;
675  typedef _Alloc allocator_type;
676  static_assert(__check_valid_allocator<allocator_type>::value);
677  static_assert(is_same<value_type, typename allocator_type::value_type>::value,
678                "Allocator::value_type must be same type as value_type");
679  typedef value_type& reference;
680  typedef const value_type& const_reference;
681  typedef typename __base::pointer pointer;
682  typedef typename __base::const_pointer const_pointer;
683  typedef typename __base::size_type size_type;
684  typedef typename __base::difference_type difference_type;
685  typedef typename __base::iterator iterator;
686  typedef typename __base::const_iterator const_iterator;
687  typedef std::reverse_iterator<iterator> reverse_iterator;
688  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
689#  if _LIBCPP_STD_VER >= 20
690  typedef size_type __remove_return_type;
691#  else
692  typedef void __remove_return_type;
693#  endif
694
695  _LIBCPP_HIDE_FROM_ABI list() _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value) {}
696  _LIBCPP_HIDE_FROM_ABI explicit list(const allocator_type& __a) : __base(__a) {}
697  _LIBCPP_HIDE_FROM_ABI explicit list(size_type __n);
698#  if _LIBCPP_STD_VER >= 14
699  _LIBCPP_HIDE_FROM_ABI explicit list(size_type __n, const allocator_type& __a);
700#  endif
701  _LIBCPP_HIDE_FROM_ABI list(size_type __n, const value_type& __x);
702  template <__enable_if_t<__is_allocator<_Alloc>::value, int> = 0>
703  _LIBCPP_HIDE_FROM_ABI list(size_type __n, const value_type& __x, const allocator_type& __a) : __base(__a) {
704    for (; __n > 0; --__n)
705      push_back(__x);
706  }
707
708  template <class _InpIter, __enable_if_t<__has_input_iterator_category<_InpIter>::value, int> = 0>
709  _LIBCPP_HIDE_FROM_ABI list(_InpIter __f, _InpIter __l);
710
711  template <class _InpIter, __enable_if_t<__has_input_iterator_category<_InpIter>::value, int> = 0>
712  _LIBCPP_HIDE_FROM_ABI list(_InpIter __f, _InpIter __l, const allocator_type& __a);
713
714#  if _LIBCPP_STD_VER >= 23
715  template <_ContainerCompatibleRange<_Tp> _Range>
716  _LIBCPP_HIDE_FROM_ABI list(from_range_t, _Range&& __range, const allocator_type& __a = allocator_type())
717      : __base(__a) {
718    prepend_range(std::forward<_Range>(__range));
719  }
720#  endif
721
722  _LIBCPP_HIDE_FROM_ABI list(const list& __c);
723  _LIBCPP_HIDE_FROM_ABI list(const list& __c, const __type_identity_t<allocator_type>& __a);
724  _LIBCPP_HIDE_FROM_ABI list& operator=(const list& __c);
725#  ifndef _LIBCPP_CXX03_LANG
726  _LIBCPP_HIDE_FROM_ABI list(initializer_list<value_type> __il);
727  _LIBCPP_HIDE_FROM_ABI list(initializer_list<value_type> __il, const allocator_type& __a);
728
729  _LIBCPP_HIDE_FROM_ABI list(list&& __c) _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value);
730  _LIBCPP_HIDE_FROM_ABI list(list&& __c, const __type_identity_t<allocator_type>& __a);
731  _LIBCPP_HIDE_FROM_ABI list& operator=(list&& __c)
732      _NOEXCEPT_(__node_alloc_traits::propagate_on_container_move_assignment::value&&
733                     is_nothrow_move_assignable<__node_allocator>::value);
734
735  _LIBCPP_HIDE_FROM_ABI list& operator=(initializer_list<value_type> __il) {
736    assign(__il.begin(), __il.end());
737    return *this;
738  }
739
740  _LIBCPP_HIDE_FROM_ABI void assign(initializer_list<value_type> __il) { assign(__il.begin(), __il.end()); }
741#  endif // _LIBCPP_CXX03_LANG
742
743  template <class _InpIter, __enable_if_t<__has_input_iterator_category<_InpIter>::value, int> = 0>
744  _LIBCPP_HIDE_FROM_ABI void assign(_InpIter __f, _InpIter __l);
745
746#  if _LIBCPP_STD_VER >= 23
747  template <_ContainerCompatibleRange<_Tp> _Range>
748  _LIBCPP_HIDE_FROM_ABI void assign_range(_Range&& __range) {
749    __assign_with_sentinel(ranges::begin(__range), ranges::end(__range));
750  }
751#  endif
752
753  _LIBCPP_HIDE_FROM_ABI void assign(size_type __n, const value_type& __x);
754
755  _LIBCPP_HIDE_FROM_ABI allocator_type get_allocator() const _NOEXCEPT;
756
757  _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return this->__size_; }
758  [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __base::empty(); }
759  _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT {
760    return std::min<size_type>(this->__node_alloc_max_size(), numeric_limits<difference_type >::max());
761  }
762
763  _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return __base::begin(); }
764  _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return __base::begin(); }
765  _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return __base::end(); }
766  _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return __base::end(); }
767  _LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT { return __base::begin(); }
768  _LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT { return __base::end(); }
769
770  _LIBCPP_HIDE_FROM_ABI reverse_iterator rbegin() _NOEXCEPT { return reverse_iterator(end()); }
771  _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rbegin() const _NOEXCEPT { return const_reverse_iterator(end()); }
772  _LIBCPP_HIDE_FROM_ABI reverse_iterator rend() _NOEXCEPT { return reverse_iterator(begin()); }
773  _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rend() const _NOEXCEPT { return const_reverse_iterator(begin()); }
774  _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crbegin() const _NOEXCEPT { return const_reverse_iterator(end()); }
775  _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crend() const _NOEXCEPT { return const_reverse_iterator(begin()); }
776
777  _LIBCPP_HIDE_FROM_ABI reference front() {
778    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "list::front called on empty list");
779    return __base::__end_.__next_->__as_node()->__get_value();
780  }
781  _LIBCPP_HIDE_FROM_ABI const_reference front() const {
782    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "list::front called on empty list");
783    return __base::__end_.__next_->__as_node()->__get_value();
784  }
785  _LIBCPP_HIDE_FROM_ABI reference back() {
786    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "list::back called on empty list");
787    return __base::__end_.__prev_->__as_node()->__get_value();
788  }
789  _LIBCPP_HIDE_FROM_ABI const_reference back() const {
790    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "list::back called on empty list");
791    return __base::__end_.__prev_->__as_node()->__get_value();
792  }
793
794#  ifndef _LIBCPP_CXX03_LANG
795  _LIBCPP_HIDE_FROM_ABI void push_front(value_type&& __x);
796  _LIBCPP_HIDE_FROM_ABI void push_back(value_type&& __x);
797
798#    if _LIBCPP_STD_VER >= 23
799  template <_ContainerCompatibleRange<_Tp> _Range>
800  _LIBCPP_HIDE_FROM_ABI void prepend_range(_Range&& __range) {
801    insert_range(begin(), std::forward<_Range>(__range));
802  }
803
804  template <_ContainerCompatibleRange<_Tp> _Range>
805  _LIBCPP_HIDE_FROM_ABI void append_range(_Range&& __range) {
806    insert_range(end(), std::forward<_Range>(__range));
807  }
808#    endif
809
810  template <class... _Args>
811#    if _LIBCPP_STD_VER >= 17
812  _LIBCPP_HIDE_FROM_ABI reference emplace_front(_Args&&... __args);
813#    else
814  _LIBCPP_HIDE_FROM_ABI void emplace_front(_Args&&... __args);
815#    endif
816  template <class... _Args>
817#    if _LIBCPP_STD_VER >= 17
818  _LIBCPP_HIDE_FROM_ABI reference emplace_back(_Args&&... __args);
819#    else
820  _LIBCPP_HIDE_FROM_ABI void emplace_back(_Args&&... __args);
821#    endif
822  template <class... _Args>
823  _LIBCPP_HIDE_FROM_ABI iterator emplace(const_iterator __p, _Args&&... __args);
824
825  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, value_type&& __x);
826
827  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, initializer_list<value_type> __il) {
828    return insert(__p, __il.begin(), __il.end());
829  }
830#  endif // _LIBCPP_CXX03_LANG
831
832  _LIBCPP_HIDE_FROM_ABI void push_front(const value_type& __x);
833  _LIBCPP_HIDE_FROM_ABI void push_back(const value_type& __x);
834
835#  ifndef _LIBCPP_CXX03_LANG
836  template <class _Arg>
837  _LIBCPP_HIDE_FROM_ABI void __emplace_back(_Arg&& __arg) {
838    emplace_back(std::forward<_Arg>(__arg));
839  }
840#  else
841  _LIBCPP_HIDE_FROM_ABI void __emplace_back(value_type const& __arg) { push_back(__arg); }
842#  endif
843
844  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, const value_type& __x);
845  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, size_type __n, const value_type& __x);
846
847  template <class _InpIter, __enable_if_t<__has_input_iterator_category<_InpIter>::value, int> = 0>
848  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, _InpIter __f, _InpIter __l);
849
850#  if _LIBCPP_STD_VER >= 23
851  template <_ContainerCompatibleRange<_Tp> _Range>
852  _LIBCPP_HIDE_FROM_ABI iterator insert_range(const_iterator __position, _Range&& __range) {
853    return __insert_with_sentinel(__position, ranges::begin(__range), ranges::end(__range));
854  }
855#  endif
856
857  _LIBCPP_HIDE_FROM_ABI void swap(list& __c)
858#  if _LIBCPP_STD_VER >= 14
859      _NOEXCEPT
860#  else
861      _NOEXCEPT_(!__node_alloc_traits::propagate_on_container_swap::value || __is_nothrow_swappable_v<__node_allocator>)
862#  endif
863  {
864    __base::swap(__c);
865  }
866  _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT { __base::clear(); }
867
868  _LIBCPP_HIDE_FROM_ABI void pop_front();
869  _LIBCPP_HIDE_FROM_ABI void pop_back();
870
871  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __p);
872  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __f, const_iterator __l);
873
874  _LIBCPP_HIDE_FROM_ABI void resize(size_type __n);
875  _LIBCPP_HIDE_FROM_ABI void resize(size_type __n, const value_type& __x);
876
877  _LIBCPP_HIDE_FROM_ABI void splice(const_iterator __p, list& __c);
878#  ifndef _LIBCPP_CXX03_LANG
879  _LIBCPP_HIDE_FROM_ABI void splice(const_iterator __p, list&& __c) { splice(__p, __c); }
880  _LIBCPP_HIDE_FROM_ABI void splice(const_iterator __p, list&& __c, const_iterator __i) { splice(__p, __c, __i); }
881  _LIBCPP_HIDE_FROM_ABI void splice(const_iterator __p, list&& __c, const_iterator __f, const_iterator __l) {
882    splice(__p, __c, __f, __l);
883  }
884#  endif
885  _LIBCPP_HIDE_FROM_ABI void splice(const_iterator __p, list& __c, const_iterator __i);
886  _LIBCPP_HIDE_FROM_ABI void splice(const_iterator __p, list& __c, const_iterator __f, const_iterator __l);
887
888  _LIBCPP_HIDE_FROM_ABI __remove_return_type remove(const value_type& __x);
889  template <class _Pred>
890  _LIBCPP_HIDE_FROM_ABI __remove_return_type remove_if(_Pred __pred);
891  _LIBCPP_HIDE_FROM_ABI __remove_return_type unique() { return unique(__equal_to()); }
892  template <class _BinaryPred>
893  _LIBCPP_HIDE_FROM_ABI __remove_return_type unique(_BinaryPred __binary_pred);
894  _LIBCPP_HIDE_FROM_ABI void merge(list& __c);
895#  ifndef _LIBCPP_CXX03_LANG
896  _LIBCPP_HIDE_FROM_ABI void merge(list&& __c) { merge(__c); }
897
898  template <class _Comp>
899  _LIBCPP_HIDE_FROM_ABI void merge(list&& __c, _Comp __comp) {
900    merge(__c, __comp);
901  }
902#  endif
903  template <class _Comp>
904  _LIBCPP_HIDE_FROM_ABI void merge(list& __c, _Comp __comp);
905
906  _LIBCPP_HIDE_FROM_ABI void sort();
907  template <class _Comp>
908  _LIBCPP_HIDE_FROM_ABI void sort(_Comp __comp);
909
910  _LIBCPP_HIDE_FROM_ABI void reverse() _NOEXCEPT;
911
912  _LIBCPP_HIDE_FROM_ABI bool __invariants() const;
913
914private:
915  template <class _Iterator, class _Sentinel>
916  _LIBCPP_HIDE_FROM_ABI void __assign_with_sentinel(_Iterator __f, _Sentinel __l);
917
918  template <class _Iterator, class _Sentinel>
919  _LIBCPP_HIDE_FROM_ABI iterator __insert_with_sentinel(const_iterator __p, _Iterator __f, _Sentinel __l);
920
921  _LIBCPP_HIDE_FROM_ABI static void __link_nodes(__base_pointer __p, __base_pointer __f, __base_pointer __l);
922  _LIBCPP_HIDE_FROM_ABI void __link_nodes_at_front(__base_pointer __f, __base_pointer __l);
923  _LIBCPP_HIDE_FROM_ABI void __link_nodes_at_back(__base_pointer __f, __base_pointer __l);
924  _LIBCPP_HIDE_FROM_ABI iterator __iterator(size_type __n);
925  // TODO: Make this _LIBCPP_HIDE_FROM_ABI
926  template <class _Comp>
927  _LIBCPP_HIDDEN static iterator __sort(iterator __f1, iterator __e2, size_type __n, _Comp& __comp);
928
929  _LIBCPP_HIDE_FROM_ABI void __move_assign(list& __c, true_type)
930      _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value);
931  _LIBCPP_HIDE_FROM_ABI void __move_assign(list& __c, false_type);
932};
933
934#  if _LIBCPP_STD_VER >= 17
935template <class _InputIterator,
936          class _Alloc = allocator<__iter_value_type<_InputIterator>>,
937          class        = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
938          class        = enable_if_t<__is_allocator<_Alloc>::value> >
939list(_InputIterator, _InputIterator) -> list<__iter_value_type<_InputIterator>, _Alloc>;
940
941template <class _InputIterator,
942          class _Alloc,
943          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
944          class = enable_if_t<__is_allocator<_Alloc>::value> >
945list(_InputIterator, _InputIterator, _Alloc) -> list<__iter_value_type<_InputIterator>, _Alloc>;
946#  endif
947
948#  if _LIBCPP_STD_VER >= 23
949template <ranges::input_range _Range,
950          class _Alloc = allocator<ranges::range_value_t<_Range>>,
951          class        = enable_if_t<__is_allocator<_Alloc>::value> >
952list(from_range_t, _Range&&, _Alloc = _Alloc()) -> list<ranges::range_value_t<_Range>, _Alloc>;
953#  endif
954
955// Link in nodes [__f, __l] just prior to __p
956template <class _Tp, class _Alloc>
957inline void list<_Tp, _Alloc>::__link_nodes(__base_pointer __p, __base_pointer __f, __base_pointer __l) {
958  __p->__prev_->__next_ = __f;
959  __f->__prev_          = __p->__prev_;
960  __p->__prev_          = __l;
961  __l->__next_          = __p;
962}
963
964// Link in nodes [__f, __l] at the front of the list
965template <class _Tp, class _Alloc>
966inline void list<_Tp, _Alloc>::__link_nodes_at_front(__base_pointer __f, __base_pointer __l) {
967  __f->__prev_           = __base::__end_as_link();
968  __l->__next_           = __base::__end_.__next_;
969  __l->__next_->__prev_  = __l;
970  __base::__end_.__next_ = __f;
971}
972
973// Link in nodes [__f, __l] at the back of the list
974template <class _Tp, class _Alloc>
975inline void list<_Tp, _Alloc>::__link_nodes_at_back(__base_pointer __f, __base_pointer __l) {
976  __l->__next_           = __base::__end_as_link();
977  __f->__prev_           = __base::__end_.__prev_;
978  __f->__prev_->__next_  = __f;
979  __base::__end_.__prev_ = __l;
980}
981
982template <class _Tp, class _Alloc>
983inline typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::__iterator(size_type __n) {
984  return __n <= this->__size_ / 2 ? std::next(begin(), __n) : std::prev(end(), this->__size_ - __n);
985}
986
987template <class _Tp, class _Alloc>
988list<_Tp, _Alloc>::list(size_type __n) {
989  for (; __n > 0; --__n)
990#  ifndef _LIBCPP_CXX03_LANG
991    emplace_back();
992#  else
993    push_back(value_type());
994#  endif
995}
996
997#  if _LIBCPP_STD_VER >= 14
998template <class _Tp, class _Alloc>
999list<_Tp, _Alloc>::list(size_type __n, const allocator_type& __a) : __base(__a) {
1000  for (; __n > 0; --__n)
1001    emplace_back();
1002}
1003#  endif
1004
1005template <class _Tp, class _Alloc>
1006list<_Tp, _Alloc>::list(size_type __n, const value_type& __x) {
1007  for (; __n > 0; --__n)
1008    push_back(__x);
1009}
1010
1011template <class _Tp, class _Alloc>
1012template <class _InpIter, __enable_if_t<__has_input_iterator_category<_InpIter>::value, int> >
1013list<_Tp, _Alloc>::list(_InpIter __f, _InpIter __l) {
1014  for (; __f != __l; ++__f)
1015    __emplace_back(*__f);
1016}
1017
1018template <class _Tp, class _Alloc>
1019template <class _InpIter, __enable_if_t<__has_input_iterator_category<_InpIter>::value, int> >
1020list<_Tp, _Alloc>::list(_InpIter __f, _InpIter __l, const allocator_type& __a) : __base(__a) {
1021  for (; __f != __l; ++__f)
1022    __emplace_back(*__f);
1023}
1024
1025template <class _Tp, class _Alloc>
1026list<_Tp, _Alloc>::list(const list& __c)
1027    : __base(__node_alloc_traits::select_on_container_copy_construction(__c.__node_alloc_)) {
1028  for (const_iterator __i = __c.begin(), __e = __c.end(); __i != __e; ++__i)
1029    push_back(*__i);
1030}
1031
1032template <class _Tp, class _Alloc>
1033list<_Tp, _Alloc>::list(const list& __c, const __type_identity_t<allocator_type>& __a) : __base(__a) {
1034  for (const_iterator __i = __c.begin(), __e = __c.end(); __i != __e; ++__i)
1035    push_back(*__i);
1036}
1037
1038#  ifndef _LIBCPP_CXX03_LANG
1039
1040template <class _Tp, class _Alloc>
1041list<_Tp, _Alloc>::list(initializer_list<value_type> __il, const allocator_type& __a) : __base(__a) {
1042  for (typename initializer_list<value_type>::const_iterator __i = __il.begin(), __e = __il.end(); __i != __e; ++__i)
1043    push_back(*__i);
1044}
1045
1046template <class _Tp, class _Alloc>
1047list<_Tp, _Alloc>::list(initializer_list<value_type> __il) {
1048  for (typename initializer_list<value_type>::const_iterator __i = __il.begin(), __e = __il.end(); __i != __e; ++__i)
1049    push_back(*__i);
1050}
1051
1052template <class _Tp, class _Alloc>
1053inline list<_Tp, _Alloc>::list(list&& __c) noexcept(is_nothrow_move_constructible<__node_allocator>::value)
1054    : __base(std::move(__c.__node_alloc_)) {
1055  splice(end(), __c);
1056}
1057
1058template <class _Tp, class _Alloc>
1059inline list<_Tp, _Alloc>::list(list&& __c, const __type_identity_t<allocator_type>& __a) : __base(__a) {
1060  if (__a == __c.get_allocator())
1061    splice(end(), __c);
1062  else {
1063    typedef move_iterator<iterator> _Ip;
1064    assign(_Ip(__c.begin()), _Ip(__c.end()));
1065  }
1066}
1067
1068template <class _Tp, class _Alloc>
1069inline list<_Tp, _Alloc>& list<_Tp, _Alloc>::operator=(list&& __c) noexcept(
1070    __node_alloc_traits::propagate_on_container_move_assignment::value &&
1071    is_nothrow_move_assignable<__node_allocator>::value) {
1072  __move_assign(__c, integral_constant<bool, __node_alloc_traits::propagate_on_container_move_assignment::value>());
1073  return *this;
1074}
1075
1076template <class _Tp, class _Alloc>
1077void list<_Tp, _Alloc>::__move_assign(list& __c, false_type) {
1078  if (this->__node_alloc_ != __c.__node_alloc_) {
1079    typedef move_iterator<iterator> _Ip;
1080    assign(_Ip(__c.begin()), _Ip(__c.end()));
1081  } else
1082    __move_assign(__c, true_type());
1083}
1084
1085template <class _Tp, class _Alloc>
1086void list<_Tp, _Alloc>::__move_assign(list& __c,
1087                                      true_type) noexcept(is_nothrow_move_assignable<__node_allocator>::value) {
1088  clear();
1089  __base::__move_assign_alloc(__c);
1090  splice(end(), __c);
1091}
1092
1093#  endif // _LIBCPP_CXX03_LANG
1094
1095template <class _Tp, class _Alloc>
1096inline list<_Tp, _Alloc>& list<_Tp, _Alloc>::operator=(const list& __c) {
1097  if (this != std::addressof(__c)) {
1098    __base::__copy_assign_alloc(__c);
1099    assign(__c.begin(), __c.end());
1100  }
1101  return *this;
1102}
1103
1104template <class _Tp, class _Alloc>
1105template <class _InpIter, __enable_if_t<__has_input_iterator_category<_InpIter>::value, int> >
1106void list<_Tp, _Alloc>::assign(_InpIter __f, _InpIter __l) {
1107  __assign_with_sentinel(__f, __l);
1108}
1109
1110template <class _Tp, class _Alloc>
1111template <class _Iterator, class _Sentinel>
1112_LIBCPP_HIDE_FROM_ABI void list<_Tp, _Alloc>::__assign_with_sentinel(_Iterator __f, _Sentinel __l) {
1113  iterator __i = begin();
1114  iterator __e = end();
1115  for (; __f != __l && __i != __e; ++__f, (void)++__i)
1116    *__i = *__f;
1117  if (__i == __e)
1118    __insert_with_sentinel(__e, std::move(__f), std::move(__l));
1119  else
1120    erase(__i, __e);
1121}
1122
1123template <class _Tp, class _Alloc>
1124void list<_Tp, _Alloc>::assign(size_type __n, const value_type& __x) {
1125  iterator __i = begin();
1126  iterator __e = end();
1127  for (; __n > 0 && __i != __e; --__n, (void)++__i)
1128    *__i = __x;
1129  if (__i == __e)
1130    insert(__e, __n, __x);
1131  else
1132    erase(__i, __e);
1133}
1134
1135template <class _Tp, class _Alloc>
1136inline _Alloc list<_Tp, _Alloc>::get_allocator() const _NOEXCEPT {
1137  return allocator_type(this->__node_alloc_);
1138}
1139
1140template <class _Tp, class _Alloc>
1141typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::insert(const_iterator __p, const value_type& __x) {
1142  __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, __x);
1143  __link_nodes(__p.__ptr_, __node->__as_link(), __node->__as_link());
1144  ++this->__size_;
1145  return iterator(__node->__as_link());
1146}
1147
1148template <class _Tp, class _Alloc>
1149typename list<_Tp, _Alloc>::iterator
1150list<_Tp, _Alloc>::insert(const_iterator __p, size_type __n, const value_type& __x) {
1151  iterator __r(__p.__ptr_);
1152  if (__n > 0) {
1153    size_type __ds        = 0;
1154    __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, __x);
1155    ++__ds;
1156    __r          = iterator(__node->__as_link());
1157    iterator __e = __r;
1158#  if _LIBCPP_HAS_EXCEPTIONS
1159    try {
1160#  endif // _LIBCPP_HAS_EXCEPTIONS
1161      for (--__n; __n != 0; --__n, (void)++__e, ++__ds) {
1162        __e.__ptr_->__next_ = this->__create_node(/* prev = */ __e.__ptr_, /* next = */ nullptr, __x)->__as_link();
1163      }
1164#  if _LIBCPP_HAS_EXCEPTIONS
1165    } catch (...) {
1166      while (true) {
1167        __base_pointer __prev    = __e.__ptr_->__prev_;
1168        __node_pointer __current = __e.__ptr_->__as_node();
1169        this->__delete_node(__current);
1170        if (__prev == 0)
1171          break;
1172        __e = iterator(__prev);
1173      }
1174      throw;
1175    }
1176#  endif // _LIBCPP_HAS_EXCEPTIONS
1177    __link_nodes(__p.__ptr_, __r.__ptr_, __e.__ptr_);
1178    this->__size_ += __ds;
1179  }
1180  return __r;
1181}
1182
1183template <class _Tp, class _Alloc>
1184template <class _InpIter, __enable_if_t<__has_input_iterator_category<_InpIter>::value, int> >
1185typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::insert(const_iterator __p, _InpIter __f, _InpIter __l) {
1186  return __insert_with_sentinel(__p, __f, __l);
1187}
1188
1189template <class _Tp, class _Alloc>
1190template <class _Iterator, class _Sentinel>
1191_LIBCPP_HIDE_FROM_ABI typename list<_Tp, _Alloc>::iterator
1192list<_Tp, _Alloc>::__insert_with_sentinel(const_iterator __p, _Iterator __f, _Sentinel __l) {
1193  iterator __r(__p.__ptr_);
1194  if (__f != __l) {
1195    size_type __ds        = 0;
1196    __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, *__f);
1197    ++__ds;
1198    __r          = iterator(__node->__as_link());
1199    iterator __e = __r;
1200#  if _LIBCPP_HAS_EXCEPTIONS
1201    try {
1202#  endif // _LIBCPP_HAS_EXCEPTIONS
1203      for (++__f; __f != __l; ++__f, (void)++__e, ++__ds) {
1204        __e.__ptr_->__next_ = this->__create_node(/* prev = */ __e.__ptr_, /* next = */ nullptr, *__f)->__as_link();
1205      }
1206#  if _LIBCPP_HAS_EXCEPTIONS
1207    } catch (...) {
1208      while (true) {
1209        __base_pointer __prev    = __e.__ptr_->__prev_;
1210        __node_pointer __current = __e.__ptr_->__as_node();
1211        this->__delete_node(__current);
1212        if (__prev == 0)
1213          break;
1214        __e = iterator(__prev);
1215      }
1216      throw;
1217    }
1218#  endif // _LIBCPP_HAS_EXCEPTIONS
1219    __link_nodes(__p.__ptr_, __r.__ptr_, __e.__ptr_);
1220    this->__size_ += __ds;
1221  }
1222  return __r;
1223}
1224
1225template <class _Tp, class _Alloc>
1226void list<_Tp, _Alloc>::push_front(const value_type& __x) {
1227  __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, __x);
1228  __base_pointer __nl   = __node->__as_link();
1229  __link_nodes_at_front(__nl, __nl);
1230  ++this->__size_;
1231}
1232
1233template <class _Tp, class _Alloc>
1234void list<_Tp, _Alloc>::push_back(const value_type& __x) {
1235  __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, __x);
1236  __base_pointer __nl   = __node->__as_link();
1237  __link_nodes_at_back(__nl, __nl);
1238  ++this->__size_;
1239}
1240
1241#  ifndef _LIBCPP_CXX03_LANG
1242
1243template <class _Tp, class _Alloc>
1244void list<_Tp, _Alloc>::push_front(value_type&& __x) {
1245  __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, std::move(__x));
1246  __base_pointer __nl   = __node->__as_link();
1247  __link_nodes_at_front(__nl, __nl);
1248  ++this->__size_;
1249}
1250
1251template <class _Tp, class _Alloc>
1252void list<_Tp, _Alloc>::push_back(value_type&& __x) {
1253  __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, std::move(__x));
1254  __base_pointer __nl   = __node->__as_link();
1255  __link_nodes_at_back(__nl, __nl);
1256  ++this->__size_;
1257}
1258
1259template <class _Tp, class _Alloc>
1260template <class... _Args>
1261#    if _LIBCPP_STD_VER >= 17
1262typename list<_Tp, _Alloc>::reference
1263#    else
1264void
1265#    endif
1266list<_Tp, _Alloc>::emplace_front(_Args&&... __args) {
1267  __node_pointer __node =
1268      this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, std::forward<_Args>(__args)...);
1269  __base_pointer __nl = __node->__as_link();
1270  __link_nodes_at_front(__nl, __nl);
1271  ++this->__size_;
1272#    if _LIBCPP_STD_VER >= 17
1273  return __node->__get_value();
1274#    endif
1275}
1276
1277template <class _Tp, class _Alloc>
1278template <class... _Args>
1279#    if _LIBCPP_STD_VER >= 17
1280typename list<_Tp, _Alloc>::reference
1281#    else
1282void
1283#    endif
1284list<_Tp, _Alloc>::emplace_back(_Args&&... __args) {
1285  __node_pointer __node =
1286      this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, std::forward<_Args>(__args)...);
1287  __base_pointer __nl = __node->__as_link();
1288  __link_nodes_at_back(__nl, __nl);
1289  ++this->__size_;
1290#    if _LIBCPP_STD_VER >= 17
1291  return __node->__get_value();
1292#    endif
1293}
1294
1295template <class _Tp, class _Alloc>
1296template <class... _Args>
1297typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::emplace(const_iterator __p, _Args&&... __args) {
1298  __node_pointer __node =
1299      this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, std::forward<_Args>(__args)...);
1300  __base_pointer __nl = __node->__as_link();
1301  __link_nodes(__p.__ptr_, __nl, __nl);
1302  ++this->__size_;
1303  return iterator(__nl);
1304}
1305
1306template <class _Tp, class _Alloc>
1307typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::insert(const_iterator __p, value_type&& __x) {
1308  __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, std::move(__x));
1309  __base_pointer __nl   = __node->__as_link();
1310  __link_nodes(__p.__ptr_, __nl, __nl);
1311  ++this->__size_;
1312  return iterator(__nl);
1313}
1314
1315#  endif // _LIBCPP_CXX03_LANG
1316
1317template <class _Tp, class _Alloc>
1318void list<_Tp, _Alloc>::pop_front() {
1319  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "list::pop_front() called with empty list");
1320  __base_pointer __n = __base::__end_.__next_;
1321  __base::__unlink_nodes(__n, __n);
1322  --this->__size_;
1323  this->__delete_node(__n->__as_node());
1324}
1325
1326template <class _Tp, class _Alloc>
1327void list<_Tp, _Alloc>::pop_back() {
1328  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "list::pop_back() called on an empty list");
1329  __base_pointer __n = __base::__end_.__prev_;
1330  __base::__unlink_nodes(__n, __n);
1331  --this->__size_;
1332  this->__delete_node(__n->__as_node());
1333}
1334
1335template <class _Tp, class _Alloc>
1336typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::erase(const_iterator __p) {
1337  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__p != end(), "list::erase(iterator) called with a non-dereferenceable iterator");
1338  __base_pointer __n = __p.__ptr_;
1339  __base_pointer __r = __n->__next_;
1340  __base::__unlink_nodes(__n, __n);
1341  --this->__size_;
1342  this->__delete_node(__n->__as_node());
1343  return iterator(__r);
1344}
1345
1346template <class _Tp, class _Alloc>
1347typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::erase(const_iterator __f, const_iterator __l) {
1348  if (__f != __l) {
1349    __base::__unlink_nodes(__f.__ptr_, __l.__ptr_->__prev_);
1350    while (__f != __l) {
1351      __base_pointer __n = __f.__ptr_;
1352      ++__f;
1353      --this->__size_;
1354      this->__delete_node(__n->__as_node());
1355    }
1356  }
1357  return iterator(__l.__ptr_);
1358}
1359
1360template <class _Tp, class _Alloc>
1361void list<_Tp, _Alloc>::resize(size_type __n) {
1362  if (__n < this->__size_)
1363    erase(__iterator(__n), end());
1364  else if (__n > this->__size_) {
1365    __n -= this->__size_;
1366    size_type __ds        = 0;
1367    __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr);
1368    ++__ds;
1369    iterator __r = iterator(__node->__as_link());
1370    iterator __e = __r;
1371#  if _LIBCPP_HAS_EXCEPTIONS
1372    try {
1373#  endif // _LIBCPP_HAS_EXCEPTIONS
1374      for (--__n; __n != 0; --__n, (void)++__e, ++__ds) {
1375        __e.__ptr_->__next_ = this->__create_node(/* prev = */ __e.__ptr_, /* next = */ nullptr)->__as_link();
1376      }
1377#  if _LIBCPP_HAS_EXCEPTIONS
1378    } catch (...) {
1379      while (true) {
1380        __base_pointer __prev    = __e.__ptr_->__prev_;
1381        __node_pointer __current = __e.__ptr_->__as_node();
1382        this->__delete_node(__current);
1383        if (__prev == 0)
1384          break;
1385        __e = iterator(__prev);
1386      }
1387      throw;
1388    }
1389#  endif // _LIBCPP_HAS_EXCEPTIONS
1390    __link_nodes_at_back(__r.__ptr_, __e.__ptr_);
1391    this->__size_ += __ds;
1392  }
1393}
1394
1395template <class _Tp, class _Alloc>
1396void list<_Tp, _Alloc>::resize(size_type __n, const value_type& __x) {
1397  if (__n < this->__size_)
1398    erase(__iterator(__n), end());
1399  else if (__n > this->__size_) {
1400    __n -= this->__size_;
1401    size_type __ds        = 0;
1402    __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, __x);
1403    ++__ds;
1404    __base_pointer __nl = __node->__as_link();
1405    iterator __r        = iterator(__nl);
1406    iterator __e        = __r;
1407#  if _LIBCPP_HAS_EXCEPTIONS
1408    try {
1409#  endif // _LIBCPP_HAS_EXCEPTIONS
1410      for (--__n; __n != 0; --__n, (void)++__e, ++__ds) {
1411        __e.__ptr_->__next_ = this->__create_node(/* prev = */ __e.__ptr_, /* next = */ nullptr, __x)->__as_link();
1412      }
1413#  if _LIBCPP_HAS_EXCEPTIONS
1414    } catch (...) {
1415      while (true) {
1416        __base_pointer __prev    = __e.__ptr_->__prev_;
1417        __node_pointer __current = __e.__ptr_->__as_node();
1418        this->__delete_node(__current);
1419        if (__prev == 0)
1420          break;
1421        __e = iterator(__prev);
1422      }
1423      throw;
1424    }
1425#  endif // _LIBCPP_HAS_EXCEPTIONS
1426    __link_nodes(__base::__end_as_link(), __r.__ptr_, __e.__ptr_);
1427    this->__size_ += __ds;
1428  }
1429}
1430
1431template <class _Tp, class _Alloc>
1432void list<_Tp, _Alloc>::splice(const_iterator __p, list& __c) {
1433  _LIBCPP_ASSERT_VALID_INPUT_RANGE(
1434      this != std::addressof(__c), "list::splice(iterator, list) called with this == &list");
1435  if (!__c.empty()) {
1436    __base_pointer __f = __c.__end_.__next_;
1437    __base_pointer __l = __c.__end_.__prev_;
1438    __base::__unlink_nodes(__f, __l);
1439    __link_nodes(__p.__ptr_, __f, __l);
1440    this->__size_ += __c.__size_;
1441    __c.__size_ = 0;
1442  }
1443}
1444
1445template <class _Tp, class _Alloc>
1446void list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __i) {
1447  if (__p.__ptr_ != __i.__ptr_ && __p.__ptr_ != __i.__ptr_->__next_) {
1448    __base_pointer __f = __i.__ptr_;
1449    __base::__unlink_nodes(__f, __f);
1450    __link_nodes(__p.__ptr_, __f, __f);
1451    --__c.__size_;
1452    ++this->__size_;
1453  }
1454}
1455
1456template <class _Tp, class _Alloc>
1457void list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __f, const_iterator __l) {
1458  if (__f != __l) {
1459    __base_pointer __first = __f.__ptr_;
1460    --__l;
1461    __base_pointer __last = __l.__ptr_;
1462    if (this != std::addressof(__c)) {
1463      size_type __s = std::distance(__f, __l) + 1;
1464      __c.__size_ -= __s;
1465      this->__size_ += __s;
1466    }
1467    __base::__unlink_nodes(__first, __last);
1468    __link_nodes(__p.__ptr_, __first, __last);
1469  }
1470}
1471
1472template <class _Tp, class _Alloc>
1473typename list<_Tp, _Alloc>::__remove_return_type list<_Tp, _Alloc>::remove(const value_type& __x) {
1474  list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
1475  for (const_iterator __i = begin(), __e = end(); __i != __e;) {
1476    if (*__i == __x) {
1477      const_iterator __j = std::next(__i);
1478      for (; __j != __e && *__j == __x; ++__j)
1479        ;
1480      __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
1481      __i = __j;
1482      if (__i != __e)
1483        ++__i;
1484    } else
1485      ++__i;
1486  }
1487
1488  return (__remove_return_type)__deleted_nodes.size();
1489}
1490
1491template <class _Tp, class _Alloc>
1492template <class _Pred>
1493typename list<_Tp, _Alloc>::__remove_return_type list<_Tp, _Alloc>::remove_if(_Pred __pred) {
1494  list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
1495  for (iterator __i = begin(), __e = end(); __i != __e;) {
1496    if (__pred(*__i)) {
1497      iterator __j = std::next(__i);
1498      for (; __j != __e && __pred(*__j); ++__j)
1499        ;
1500      __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
1501      __i = __j;
1502      if (__i != __e)
1503        ++__i;
1504    } else
1505      ++__i;
1506  }
1507
1508  return (__remove_return_type)__deleted_nodes.size();
1509}
1510
1511template <class _Tp, class _Alloc>
1512template <class _BinaryPred>
1513typename list<_Tp, _Alloc>::__remove_return_type list<_Tp, _Alloc>::unique(_BinaryPred __binary_pred) {
1514  list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
1515  for (iterator __i = begin(), __e = end(); __i != __e;) {
1516    iterator __j = std::next(__i);
1517    for (; __j != __e && __binary_pred(*__i, *__j); ++__j)
1518      ;
1519    if (++__i != __j) {
1520      __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
1521      __i = __j;
1522    }
1523  }
1524
1525  return (__remove_return_type)__deleted_nodes.size();
1526}
1527
1528template <class _Tp, class _Alloc>
1529inline void list<_Tp, _Alloc>::merge(list& __c) {
1530  merge(__c, __less<>());
1531}
1532
1533template <class _Tp, class _Alloc>
1534template <class _Comp>
1535void list<_Tp, _Alloc>::merge(list& __c, _Comp __comp) {
1536  if (this != std::addressof(__c)) {
1537    iterator __f1 = begin();
1538    iterator __e1 = end();
1539    iterator __f2 = __c.begin();
1540    iterator __e2 = __c.end();
1541    while (__f1 != __e1 && __f2 != __e2) {
1542      if (__comp(*__f2, *__f1)) {
1543        size_type __ds = 1;
1544        iterator __m2  = std::next(__f2);
1545        for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2, (void)++__ds)
1546          ;
1547        this->__size_ += __ds;
1548        __c.__size_ -= __ds;
1549        __base_pointer __f = __f2.__ptr_;
1550        __base_pointer __l = __m2.__ptr_->__prev_;
1551        __f2               = __m2;
1552        __base::__unlink_nodes(__f, __l);
1553        __m2 = std::next(__f1);
1554        __link_nodes(__f1.__ptr_, __f, __l);
1555        __f1 = __m2;
1556      } else
1557        ++__f1;
1558    }
1559    splice(__e1, __c);
1560  }
1561}
1562
1563template <class _Tp, class _Alloc>
1564inline void list<_Tp, _Alloc>::sort() {
1565  sort(__less<>());
1566}
1567
1568template <class _Tp, class _Alloc>
1569template <class _Comp>
1570inline void list<_Tp, _Alloc>::sort(_Comp __comp) {
1571  __sort(begin(), end(), this->__size_, __comp);
1572}
1573
1574template <class _Tp, class _Alloc>
1575template <class _Comp>
1576typename list<_Tp, _Alloc>::iterator
1577list<_Tp, _Alloc>::__sort(iterator __f1, iterator __e2, size_type __n, _Comp& __comp) {
1578  switch (__n) {
1579  case 0:
1580  case 1:
1581    return __f1;
1582  case 2:
1583    if (__comp(*--__e2, *__f1)) {
1584      __base_pointer __f = __e2.__ptr_;
1585      __base::__unlink_nodes(__f, __f);
1586      __link_nodes(__f1.__ptr_, __f, __f);
1587      return __e2;
1588    }
1589    return __f1;
1590  }
1591  size_type __n2 = __n / 2;
1592  iterator __e1  = std::next(__f1, __n2);
1593  iterator __r = __f1 = __sort(__f1, __e1, __n2, __comp);
1594  iterator __f2 = __e1 = __sort(__e1, __e2, __n - __n2, __comp);
1595  if (__comp(*__f2, *__f1)) {
1596    iterator __m2 = std::next(__f2);
1597    for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2)
1598      ;
1599    __base_pointer __f = __f2.__ptr_;
1600    __base_pointer __l = __m2.__ptr_->__prev_;
1601    __r                = __f2;
1602    __e1 = __f2 = __m2;
1603    __base::__unlink_nodes(__f, __l);
1604    __m2 = std::next(__f1);
1605    __link_nodes(__f1.__ptr_, __f, __l);
1606    __f1 = __m2;
1607  } else
1608    ++__f1;
1609  while (__f1 != __e1 && __f2 != __e2) {
1610    if (__comp(*__f2, *__f1)) {
1611      iterator __m2 = std::next(__f2);
1612      for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2)
1613        ;
1614      __base_pointer __f = __f2.__ptr_;
1615      __base_pointer __l = __m2.__ptr_->__prev_;
1616      if (__e1 == __f2)
1617        __e1 = __m2;
1618      __f2 = __m2;
1619      __base::__unlink_nodes(__f, __l);
1620      __m2 = std::next(__f1);
1621      __link_nodes(__f1.__ptr_, __f, __l);
1622      __f1 = __m2;
1623    } else
1624      ++__f1;
1625  }
1626  return __r;
1627}
1628
1629template <class _Tp, class _Alloc>
1630void list<_Tp, _Alloc>::reverse() _NOEXCEPT {
1631  if (this->__size_ > 1) {
1632    iterator __e = end();
1633    for (iterator __i = begin(); __i.__ptr_ != __e.__ptr_;) {
1634      std::swap(__i.__ptr_->__prev_, __i.__ptr_->__next_);
1635      __i.__ptr_ = __i.__ptr_->__prev_;
1636    }
1637    std::swap(__e.__ptr_->__prev_, __e.__ptr_->__next_);
1638  }
1639}
1640
1641template <class _Tp, class _Alloc>
1642bool list<_Tp, _Alloc>::__invariants() const {
1643  return size() == std::distance(begin(), end());
1644}
1645
1646template <class _Tp, class _Alloc>
1647inline _LIBCPP_HIDE_FROM_ABI bool operator==(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y) {
1648  return __x.size() == __y.size() && std::equal(__x.begin(), __x.end(), __y.begin());
1649}
1650
1651#  if _LIBCPP_STD_VER <= 17
1652
1653template <class _Tp, class _Alloc>
1654inline _LIBCPP_HIDE_FROM_ABI bool operator<(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y) {
1655  return std::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
1656}
1657
1658template <class _Tp, class _Alloc>
1659inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y) {
1660  return !(__x == __y);
1661}
1662
1663template <class _Tp, class _Alloc>
1664inline _LIBCPP_HIDE_FROM_ABI bool operator>(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y) {
1665  return __y < __x;
1666}
1667
1668template <class _Tp, class _Alloc>
1669inline _LIBCPP_HIDE_FROM_ABI bool operator>=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y) {
1670  return !(__x < __y);
1671}
1672
1673template <class _Tp, class _Alloc>
1674inline _LIBCPP_HIDE_FROM_ABI bool operator<=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y) {
1675  return !(__y < __x);
1676}
1677
1678#  else // _LIBCPP_STD_VER <= 17
1679
1680template <class _Tp, class _Allocator>
1681_LIBCPP_HIDE_FROM_ABI __synth_three_way_result<_Tp>
1682operator<=>(const list<_Tp, _Allocator>& __x, const list<_Tp, _Allocator>& __y) {
1683  return std::lexicographical_compare_three_way(__x.begin(), __x.end(), __y.begin(), __y.end(), std::__synth_three_way);
1684}
1685
1686#  endif // _LIBCPP_STD_VER <= 17
1687
1688template <class _Tp, class _Alloc>
1689inline _LIBCPP_HIDE_FROM_ABI void swap(list<_Tp, _Alloc>& __x, list<_Tp, _Alloc>& __y)
1690    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
1691  __x.swap(__y);
1692}
1693
1694#  if _LIBCPP_STD_VER >= 20
1695template <class _Tp, class _Allocator, class _Predicate>
1696inline _LIBCPP_HIDE_FROM_ABI typename list<_Tp, _Allocator>::size_type
1697erase_if(list<_Tp, _Allocator>& __c, _Predicate __pred) {
1698  return __c.remove_if(__pred);
1699}
1700
1701template <class _Tp, class _Allocator, class _Up>
1702inline _LIBCPP_HIDE_FROM_ABI typename list<_Tp, _Allocator>::size_type
1703erase(list<_Tp, _Allocator>& __c, const _Up& __v) {
1704  return std::erase_if(__c, [&](auto& __elem) { return __elem == __v; });
1705}
1706
1707template <>
1708inline constexpr bool __format::__enable_insertable<std::list<char>> = true;
1709#    if _LIBCPP_HAS_WIDE_CHARACTERS
1710template <>
1711inline constexpr bool __format::__enable_insertable<std::list<wchar_t>> = true;
1712#    endif
1713
1714#  endif // _LIBCPP_STD_VER >= 20
1715
1716template <class _Tp, class _Allocator>
1717struct __container_traits<list<_Tp, _Allocator> > {
1718  // http://eel.is/c++draft/container.reqmts
1719  // Unless otherwise specified (see [associative.reqmts.except], [unord.req.except], [deque.modifiers],
1720  // [inplace.vector.modifiers], and [vector.modifiers]) all container types defined in this Clause meet the following
1721  // additional requirements:
1722  // - If an exception is thrown by an insert() or emplace() function while inserting a single element, that
1723  // function has no effects.
1724  static _LIBCPP_CONSTEXPR const bool __emplacement_has_strong_exception_safety_guarantee = true;
1725};
1726
1727_LIBCPP_END_NAMESPACE_STD
1728
1729#  if _LIBCPP_STD_VER >= 17
1730_LIBCPP_BEGIN_NAMESPACE_STD
1731namespace pmr {
1732template <class _ValueT>
1733using list _LIBCPP_AVAILABILITY_PMR = std::list<_ValueT, polymorphic_allocator<_ValueT>>;
1734} // namespace pmr
1735_LIBCPP_END_NAMESPACE_STD
1736#  endif
1737
1738_LIBCPP_POP_MACROS
1739
1740#  if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1741#    include <algorithm>
1742#    include <atomic>
1743#    include <concepts>
1744#    include <cstdint>
1745#    include <cstdlib>
1746#    include <functional>
1747#    include <iosfwd>
1748#    include <iterator>
1749#    include <stdexcept>
1750#    include <type_traits>
1751#    include <typeinfo>
1752#  endif
1753#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
1754
1755#endif // _LIBCPP_LIST
1756