xref: /freebsd/contrib/llvm-project/libcxx/include/list (revision 6580f5c38dd5b01aeeaed16b370f1a12423437f0)
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#include <__algorithm/comp.h>
201#include <__algorithm/equal.h>
202#include <__algorithm/lexicographical_compare.h>
203#include <__algorithm/lexicographical_compare_three_way.h>
204#include <__algorithm/min.h>
205#include <__assert> // all public C++ headers provide the assertion handler
206#include <__availability>
207#include <__config>
208#include <__format/enable_insertable.h>
209#include <__iterator/distance.h>
210#include <__iterator/iterator_traits.h>
211#include <__iterator/move_iterator.h>
212#include <__iterator/next.h>
213#include <__iterator/prev.h>
214#include <__iterator/reverse_iterator.h>
215#include <__memory/addressof.h>
216#include <__memory/allocation_guard.h>
217#include <__memory/allocator.h>
218#include <__memory/allocator_traits.h>
219#include <__memory/compressed_pair.h>
220#include <__memory/construct_at.h>
221#include <__memory/pointer_traits.h>
222#include <__memory/swap_allocator.h>
223#include <__memory_resource/polymorphic_allocator.h>
224#include <__ranges/access.h>
225#include <__ranges/concepts.h>
226#include <__ranges/container_compatible_range.h>
227#include <__ranges/from_range.h>
228#include <__type_traits/conditional.h>
229#include <__type_traits/is_allocator.h>
230#include <__type_traits/is_nothrow_default_constructible.h>
231#include <__type_traits/is_nothrow_move_assignable.h>
232#include <__type_traits/is_nothrow_move_constructible.h>
233#include <__type_traits/is_pointer.h>
234#include <__type_traits/is_same.h>
235#include <__type_traits/type_identity.h>
236#include <__utility/forward.h>
237#include <__utility/move.h>
238#include <__utility/swap.h>
239#include <cstring>
240#include <limits>
241#include <new> // __launder
242#include <version>
243
244// standard-mandated includes
245
246// [iterator.range]
247#include <__iterator/access.h>
248#include <__iterator/data.h>
249#include <__iterator/empty.h>
250#include <__iterator/reverse_access.h>
251#include <__iterator/size.h>
252
253// [list.syn]
254#include <compare>
255#include <initializer_list>
256
257#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
258#  pragma GCC system_header
259#endif
260
261_LIBCPP_PUSH_MACROS
262#include <__undef_macros>
263
264_LIBCPP_BEGIN_NAMESPACE_STD
265
266template <class _Tp, class _VoidPtr>
267struct __list_node;
268template <class _Tp, class _VoidPtr>
269struct __list_node_base;
270
271template <class _Tp, class _VoidPtr>
272struct __list_node_pointer_traits {
273  typedef __rebind_pointer_t<_VoidPtr, __list_node<_Tp, _VoidPtr> > __node_pointer;
274  typedef __rebind_pointer_t<_VoidPtr, __list_node_base<_Tp, _VoidPtr> > __base_pointer;
275
276#if defined(_LIBCPP_ABI_LIST_REMOVE_NODE_POINTER_UB)
277  typedef __base_pointer __link_pointer;
278#else
279  typedef __conditional_t<is_pointer<_VoidPtr>::value, __base_pointer, __node_pointer> __link_pointer;
280#endif
281
282  typedef __conditional_t<is_same<__link_pointer, __node_pointer>::value, __base_pointer, __node_pointer>
283      __non_link_pointer;
284
285  static _LIBCPP_HIDE_FROM_ABI __link_pointer __unsafe_link_pointer_cast(__link_pointer __p) { return __p; }
286
287  static _LIBCPP_HIDE_FROM_ABI __link_pointer __unsafe_link_pointer_cast(__non_link_pointer __p) {
288    return static_cast<__link_pointer>(static_cast<_VoidPtr>(__p));
289  }
290};
291
292template <class _Tp, class _VoidPtr>
293struct __list_node_base {
294  typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
295  typedef typename _NodeTraits::__node_pointer __node_pointer;
296  typedef typename _NodeTraits::__base_pointer __base_pointer;
297  typedef typename _NodeTraits::__link_pointer __link_pointer;
298
299  __link_pointer __prev_;
300  __link_pointer __next_;
301
302  _LIBCPP_HIDE_FROM_ABI __list_node_base()
303      : __prev_(_NodeTraits::__unsafe_link_pointer_cast(__self())),
304        __next_(_NodeTraits::__unsafe_link_pointer_cast(__self())) {}
305
306  _LIBCPP_HIDE_FROM_ABI explicit __list_node_base(__link_pointer __prev, __link_pointer __next)
307      : __prev_(__prev), __next_(__next) {}
308
309  _LIBCPP_HIDE_FROM_ABI __base_pointer __self() { return pointer_traits<__base_pointer>::pointer_to(*this); }
310
311  _LIBCPP_HIDE_FROM_ABI __node_pointer __as_node() { return static_cast<__node_pointer>(__self()); }
312};
313
314template <class _Tp, class _VoidPtr>
315struct __list_node : public __list_node_base<_Tp, _VoidPtr> {
316  // We allow starting the lifetime of nodes without initializing the value held by the node,
317  // since that is handled by the list itself in order to be allocator-aware.
318#ifndef _LIBCPP_CXX03_LANG
319
320private:
321  union {
322    _Tp __value_;
323  };
324
325public:
326  _LIBCPP_HIDE_FROM_ABI _Tp& __get_value() { return __value_; }
327#else
328
329private:
330  _ALIGNAS_TYPE(_Tp) char __buffer_[sizeof(_Tp)];
331
332public:
333  _LIBCPP_HIDE_FROM_ABI _Tp& __get_value() { return *std::__launder(reinterpret_cast<_Tp*>(&__buffer_)); }
334#endif
335
336  typedef __list_node_base<_Tp, _VoidPtr> __base;
337  typedef typename __base::__link_pointer __link_pointer;
338
339  _LIBCPP_HIDE_FROM_ABI explicit __list_node(__link_pointer __prev, __link_pointer __next) : __base(__prev, __next) {}
340  _LIBCPP_HIDE_FROM_ABI ~__list_node() {}
341
342  _LIBCPP_HIDE_FROM_ABI __link_pointer __as_link() { return static_cast<__link_pointer>(__base::__self()); }
343};
344
345template <class _Tp, class _Alloc = allocator<_Tp> >
346class _LIBCPP_TEMPLATE_VIS list;
347template <class _Tp, class _Alloc>
348class __list_imp;
349template <class _Tp, class _VoidPtr>
350class _LIBCPP_TEMPLATE_VIS __list_const_iterator;
351
352template <class _Tp, class _VoidPtr>
353class _LIBCPP_TEMPLATE_VIS __list_iterator {
354  typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
355  typedef typename _NodeTraits::__link_pointer __link_pointer;
356
357  __link_pointer __ptr_;
358
359  _LIBCPP_HIDE_FROM_ABI explicit __list_iterator(__link_pointer __p) _NOEXCEPT : __ptr_(__p) {}
360
361  template <class, class>
362  friend class list;
363  template <class, class>
364  friend class __list_imp;
365  template <class, class>
366  friend class __list_const_iterator;
367
368public:
369  typedef bidirectional_iterator_tag iterator_category;
370  typedef _Tp value_type;
371  typedef value_type& reference;
372  typedef __rebind_pointer_t<_VoidPtr, value_type> pointer;
373  typedef typename pointer_traits<pointer>::difference_type difference_type;
374
375  _LIBCPP_HIDE_FROM_ABI __list_iterator() _NOEXCEPT : __ptr_(nullptr) {}
376
377  _LIBCPP_HIDE_FROM_ABI reference operator*() const { return __ptr_->__as_node()->__get_value(); }
378  _LIBCPP_HIDE_FROM_ABI pointer operator->() const {
379    return pointer_traits<pointer>::pointer_to(__ptr_->__as_node()->__get_value());
380  }
381
382  _LIBCPP_HIDE_FROM_ABI __list_iterator& operator++() {
383    __ptr_ = __ptr_->__next_;
384    return *this;
385  }
386  _LIBCPP_HIDE_FROM_ABI __list_iterator operator++(int) {
387    __list_iterator __t(*this);
388    ++(*this);
389    return __t;
390  }
391
392  _LIBCPP_HIDE_FROM_ABI __list_iterator& operator--() {
393    __ptr_ = __ptr_->__prev_;
394    return *this;
395  }
396  _LIBCPP_HIDE_FROM_ABI __list_iterator operator--(int) {
397    __list_iterator __t(*this);
398    --(*this);
399    return __t;
400  }
401
402  friend _LIBCPP_HIDE_FROM_ABI bool operator==(const __list_iterator& __x, const __list_iterator& __y) {
403    return __x.__ptr_ == __y.__ptr_;
404  }
405  friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const __list_iterator& __x, const __list_iterator& __y) {
406    return !(__x == __y);
407  }
408};
409
410template <class _Tp, class _VoidPtr>
411class _LIBCPP_TEMPLATE_VIS __list_const_iterator {
412  typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
413  typedef typename _NodeTraits::__link_pointer __link_pointer;
414
415  __link_pointer __ptr_;
416
417  _LIBCPP_HIDE_FROM_ABI explicit __list_const_iterator(__link_pointer __p) _NOEXCEPT : __ptr_(__p) {}
418
419  template <class, class>
420  friend class list;
421  template <class, class>
422  friend class __list_imp;
423
424public:
425  typedef bidirectional_iterator_tag iterator_category;
426  typedef _Tp value_type;
427  typedef const value_type& reference;
428  typedef __rebind_pointer_t<_VoidPtr, const value_type> pointer;
429  typedef typename pointer_traits<pointer>::difference_type difference_type;
430
431  _LIBCPP_HIDE_FROM_ABI __list_const_iterator() _NOEXCEPT : __ptr_(nullptr) {}
432  _LIBCPP_HIDE_FROM_ABI __list_const_iterator(const __list_iterator<_Tp, _VoidPtr>& __p) _NOEXCEPT
433      : __ptr_(__p.__ptr_) {}
434
435  _LIBCPP_HIDE_FROM_ABI reference operator*() const { return __ptr_->__as_node()->__get_value(); }
436  _LIBCPP_HIDE_FROM_ABI pointer operator->() const {
437    return pointer_traits<pointer>::pointer_to(__ptr_->__as_node()->__get_value());
438  }
439
440  _LIBCPP_HIDE_FROM_ABI __list_const_iterator& operator++() {
441    __ptr_ = __ptr_->__next_;
442    return *this;
443  }
444  _LIBCPP_HIDE_FROM_ABI __list_const_iterator operator++(int) {
445    __list_const_iterator __t(*this);
446    ++(*this);
447    return __t;
448  }
449
450  _LIBCPP_HIDE_FROM_ABI __list_const_iterator& operator--() {
451    __ptr_ = __ptr_->__prev_;
452    return *this;
453  }
454  _LIBCPP_HIDE_FROM_ABI __list_const_iterator operator--(int) {
455    __list_const_iterator __t(*this);
456    --(*this);
457    return __t;
458  }
459
460  friend _LIBCPP_HIDE_FROM_ABI bool operator==(const __list_const_iterator& __x, const __list_const_iterator& __y) {
461    return __x.__ptr_ == __y.__ptr_;
462  }
463  friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const __list_const_iterator& __x, const __list_const_iterator& __y) {
464    return !(__x == __y);
465  }
466};
467
468template <class _Tp, class _Alloc>
469class __list_imp {
470  __list_imp(const __list_imp&);
471  __list_imp& operator=(const __list_imp&);
472
473public:
474  typedef _Alloc allocator_type;
475  typedef allocator_traits<allocator_type> __alloc_traits;
476  typedef typename __alloc_traits::size_type size_type;
477
478protected:
479  typedef _Tp value_type;
480  typedef typename __alloc_traits::void_pointer __void_pointer;
481  typedef __list_iterator<value_type, __void_pointer> iterator;
482  typedef __list_const_iterator<value_type, __void_pointer> const_iterator;
483  typedef __list_node_base<value_type, __void_pointer> __node_base;
484  typedef __list_node<value_type, __void_pointer> __node_type;
485  typedef __rebind_alloc<__alloc_traits, __node_type> __node_allocator;
486  typedef allocator_traits<__node_allocator> __node_alloc_traits;
487  typedef typename __node_alloc_traits::pointer __node_pointer;
488  typedef typename __node_alloc_traits::pointer __node_const_pointer;
489  typedef __list_node_pointer_traits<value_type, __void_pointer> __node_pointer_traits;
490  typedef typename __node_pointer_traits::__link_pointer __link_pointer;
491  typedef __link_pointer __link_const_pointer;
492  typedef typename __alloc_traits::pointer pointer;
493  typedef typename __alloc_traits::const_pointer const_pointer;
494  typedef typename __alloc_traits::difference_type difference_type;
495
496  typedef __rebind_alloc<__alloc_traits, __node_base> __node_base_allocator;
497  typedef typename allocator_traits<__node_base_allocator>::pointer __node_base_pointer;
498  static_assert((!is_same<allocator_type, __node_allocator>::value),
499                "internal allocator type must differ from user-specified "
500                "type; otherwise overload resolution breaks");
501
502  __node_base __end_;
503  __compressed_pair<size_type, __node_allocator> __size_alloc_;
504
505  _LIBCPP_HIDE_FROM_ABI __link_pointer __end_as_link() const _NOEXCEPT {
506    return __node_pointer_traits::__unsafe_link_pointer_cast(const_cast<__node_base&>(__end_).__self());
507  }
508
509  _LIBCPP_HIDE_FROM_ABI size_type& __sz() _NOEXCEPT { return __size_alloc_.first(); }
510  _LIBCPP_HIDE_FROM_ABI const size_type& __sz() const _NOEXCEPT { return __size_alloc_.first(); }
511  _LIBCPP_HIDE_FROM_ABI __node_allocator& __node_alloc() _NOEXCEPT { return __size_alloc_.second(); }
512  _LIBCPP_HIDE_FROM_ABI const __node_allocator& __node_alloc() const _NOEXCEPT { return __size_alloc_.second(); }
513
514  _LIBCPP_HIDE_FROM_ABI size_type __node_alloc_max_size() const _NOEXCEPT {
515    return __node_alloc_traits::max_size(__node_alloc());
516  }
517  _LIBCPP_HIDE_FROM_ABI static void __unlink_nodes(__link_pointer __f, __link_pointer __l) _NOEXCEPT;
518
519  _LIBCPP_HIDE_FROM_ABI __list_imp() _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value);
520  _LIBCPP_HIDE_FROM_ABI __list_imp(const allocator_type& __a);
521  _LIBCPP_HIDE_FROM_ABI __list_imp(const __node_allocator& __a);
522#ifndef _LIBCPP_CXX03_LANG
523  _LIBCPP_HIDE_FROM_ABI __list_imp(__node_allocator&& __a) _NOEXCEPT;
524#endif
525  _LIBCPP_HIDE_FROM_ABI ~__list_imp();
526  _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT;
527  _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __sz() == 0; }
528
529  _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return iterator(__end_.__next_); }
530  _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return const_iterator(__end_.__next_); }
531  _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return iterator(__end_as_link()); }
532  _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return const_iterator(__end_as_link()); }
533
534  _LIBCPP_HIDE_FROM_ABI void swap(__list_imp& __c)
535#if _LIBCPP_STD_VER >= 14
536      _NOEXCEPT;
537#else
538      _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value || __is_nothrow_swappable<allocator_type>::value);
539#endif
540
541  _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const __list_imp& __c) {
542    __copy_assign_alloc(
543        __c, integral_constant<bool, __node_alloc_traits::propagate_on_container_copy_assignment::value>());
544  }
545
546  _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__list_imp& __c)
547      _NOEXCEPT_(!__node_alloc_traits::propagate_on_container_move_assignment::value ||
548                 is_nothrow_move_assignable<__node_allocator>::value) {
549    __move_assign_alloc(
550        __c, integral_constant<bool, __node_alloc_traits::propagate_on_container_move_assignment::value>());
551  }
552
553  template <class... _Args>
554  _LIBCPP_HIDE_FROM_ABI __node_pointer __create_node(__link_pointer __prev, __link_pointer __next, _Args&&... __args) {
555    __node_allocator& __alloc = __node_alloc();
556    __allocation_guard<__node_allocator> __guard(__alloc, 1);
557    // Begin the lifetime of the node itself. Note that this doesn't begin the lifetime of the value
558    // held inside the node, since we need to use the allocator's construct() method for that.
559    //
560    // We don't use the allocator's construct() method to construct the node itself since the
561    // Cpp17FooInsertable named requirements don't require the allocator's construct() method
562    // to work on anything other than the value_type.
563    std::__construct_at(std::addressof(*__guard.__get()), __prev, __next);
564
565    // Now construct the value_type using the allocator's construct() method.
566    __node_alloc_traits::construct(
567        __alloc, std::addressof(__guard.__get()->__get_value()), std::forward<_Args>(__args)...);
568    return __guard.__release_ptr();
569  }
570
571  template <class... _Args>
572  _LIBCPP_HIDE_FROM_ABI void __delete_node(__node_pointer __node) {
573    // For the same reason as above, we use the allocator's destroy() method for the value_type,
574    // but not for the node itself.
575    __node_allocator& __alloc = __node_alloc();
576    __node_alloc_traits::destroy(__alloc, std::addressof(__node->__get_value()));
577    std::__destroy_at(std::addressof(*__node));
578    __node_alloc_traits::deallocate(__alloc, __node, 1);
579  }
580
581private:
582  _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const __list_imp& __c, true_type) {
583    if (__node_alloc() != __c.__node_alloc())
584      clear();
585    __node_alloc() = __c.__node_alloc();
586  }
587
588  _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const __list_imp&, false_type) {}
589
590  _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__list_imp& __c, true_type)
591      _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value) {
592    __node_alloc() = std::move(__c.__node_alloc());
593  }
594
595  _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__list_imp&, false_type) _NOEXCEPT {}
596};
597
598// Unlink nodes [__f, __l]
599template <class _Tp, class _Alloc>
600inline void __list_imp<_Tp, _Alloc>::__unlink_nodes(__link_pointer __f, __link_pointer __l) _NOEXCEPT {
601  __f->__prev_->__next_ = __l->__next_;
602  __l->__next_->__prev_ = __f->__prev_;
603}
604
605template <class _Tp, class _Alloc>
606inline __list_imp<_Tp, _Alloc>::__list_imp() _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)
607    : __size_alloc_(0, __default_init_tag()) {}
608
609template <class _Tp, class _Alloc>
610inline __list_imp<_Tp, _Alloc>::__list_imp(const allocator_type& __a) : __size_alloc_(0, __node_allocator(__a)) {}
611
612template <class _Tp, class _Alloc>
613inline __list_imp<_Tp, _Alloc>::__list_imp(const __node_allocator& __a) : __size_alloc_(0, __a) {}
614
615#ifndef _LIBCPP_CXX03_LANG
616template <class _Tp, class _Alloc>
617inline __list_imp<_Tp, _Alloc>::__list_imp(__node_allocator&& __a) _NOEXCEPT : __size_alloc_(0, std::move(__a)) {}
618#endif
619
620template <class _Tp, class _Alloc>
621__list_imp<_Tp, _Alloc>::~__list_imp() {
622  clear();
623}
624
625template <class _Tp, class _Alloc>
626void __list_imp<_Tp, _Alloc>::clear() _NOEXCEPT {
627  if (!empty()) {
628    __link_pointer __f = __end_.__next_;
629    __link_pointer __l = __end_as_link();
630    __unlink_nodes(__f, __l->__prev_);
631    __sz() = 0;
632    while (__f != __l) {
633      __node_pointer __np = __f->__as_node();
634      __f                 = __f->__next_;
635      __delete_node(__np);
636    }
637  }
638}
639
640template <class _Tp, class _Alloc>
641void __list_imp<_Tp, _Alloc>::swap(__list_imp& __c)
642#if _LIBCPP_STD_VER >= 14
643    _NOEXCEPT
644#else
645    _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value || __is_nothrow_swappable<allocator_type>::value)
646#endif
647{
648  _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
649      __alloc_traits::propagate_on_container_swap::value || this->__node_alloc() == __c.__node_alloc(),
650      "list::swap: Either propagate_on_container_swap must be true"
651      " or the allocators must compare equal");
652  using std::swap;
653  std::__swap_allocator(__node_alloc(), __c.__node_alloc());
654  swap(__sz(), __c.__sz());
655  swap(__end_, __c.__end_);
656  if (__sz() == 0)
657    __end_.__next_ = __end_.__prev_ = __end_as_link();
658  else
659    __end_.__prev_->__next_ = __end_.__next_->__prev_ = __end_as_link();
660  if (__c.__sz() == 0)
661    __c.__end_.__next_ = __c.__end_.__prev_ = __c.__end_as_link();
662  else
663    __c.__end_.__prev_->__next_ = __c.__end_.__next_->__prev_ = __c.__end_as_link();
664}
665
666template <class _Tp, class _Alloc /*= allocator<_Tp>*/>
667class _LIBCPP_TEMPLATE_VIS list : private __list_imp<_Tp, _Alloc> {
668  typedef __list_imp<_Tp, _Alloc> base;
669  typedef typename base::__node_type __node_type;
670  typedef typename base::__node_allocator __node_allocator;
671  typedef typename base::__node_pointer __node_pointer;
672  typedef typename base::__node_alloc_traits __node_alloc_traits;
673  typedef typename base::__node_base __node_base;
674  typedef typename base::__node_base_pointer __node_base_pointer;
675  typedef typename base::__link_pointer __link_pointer;
676
677public:
678  typedef _Tp value_type;
679  typedef _Alloc allocator_type;
680  static_assert((is_same<value_type, typename allocator_type::value_type>::value),
681                "Allocator::value_type must be same type as value_type");
682  typedef value_type& reference;
683  typedef const value_type& const_reference;
684  typedef typename base::pointer pointer;
685  typedef typename base::const_pointer const_pointer;
686  typedef typename base::size_type size_type;
687  typedef typename base::difference_type difference_type;
688  typedef typename base::iterator iterator;
689  typedef typename base::const_iterator const_iterator;
690  typedef std::reverse_iterator<iterator> reverse_iterator;
691  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
692#if _LIBCPP_STD_VER >= 20
693  typedef size_type __remove_return_type;
694#else
695  typedef void __remove_return_type;
696#endif
697
698  static_assert(is_same<allocator_type, __rebind_alloc<allocator_traits<allocator_type>, value_type> >::value,
699                "[allocator.requirements] states that rebinding an allocator to the same type should result in the "
700                "original allocator");
701
702  _LIBCPP_HIDE_FROM_ABI list() _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value) {}
703  _LIBCPP_HIDE_FROM_ABI explicit list(const allocator_type& __a) : base(__a) {}
704  _LIBCPP_HIDE_FROM_ABI explicit list(size_type __n);
705#if _LIBCPP_STD_VER >= 14
706  _LIBCPP_HIDE_FROM_ABI explicit list(size_type __n, const allocator_type& __a);
707#endif
708  _LIBCPP_HIDE_FROM_ABI list(size_type __n, const value_type& __x);
709  template <class = __enable_if_t<__is_allocator<_Alloc>::value> >
710  _LIBCPP_HIDE_FROM_ABI list(size_type __n, const value_type& __x, const allocator_type& __a) : base(__a) {
711    for (; __n > 0; --__n)
712      push_back(__x);
713  }
714
715  template <class _InpIter>
716  _LIBCPP_HIDE_FROM_ABI
717  list(_InpIter __f, _InpIter __l, __enable_if_t<__has_input_iterator_category<_InpIter>::value>* = 0);
718  template <class _InpIter>
719  _LIBCPP_HIDE_FROM_ABI
720  list(_InpIter __f,
721       _InpIter __l,
722       const allocator_type& __a,
723       __enable_if_t<__has_input_iterator_category<_InpIter>::value>* = 0);
724
725#if _LIBCPP_STD_VER >= 23
726  template <_ContainerCompatibleRange<_Tp> _Range>
727  _LIBCPP_HIDE_FROM_ABI list(from_range_t, _Range&& __range, const allocator_type& __a = allocator_type()) : base(__a) {
728    prepend_range(std::forward<_Range>(__range));
729  }
730#endif
731
732  _LIBCPP_HIDE_FROM_ABI list(const list& __c);
733  _LIBCPP_HIDE_FROM_ABI list(const list& __c, const __type_identity_t<allocator_type>& __a);
734  _LIBCPP_HIDE_FROM_ABI list& operator=(const list& __c);
735#ifndef _LIBCPP_CXX03_LANG
736  _LIBCPP_HIDE_FROM_ABI list(initializer_list<value_type> __il);
737  _LIBCPP_HIDE_FROM_ABI list(initializer_list<value_type> __il, const allocator_type& __a);
738
739  _LIBCPP_HIDE_FROM_ABI list(list&& __c) _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value);
740  _LIBCPP_HIDE_FROM_ABI list(list&& __c, const __type_identity_t<allocator_type>& __a);
741  _LIBCPP_HIDE_FROM_ABI list& operator=(list&& __c)
742      _NOEXCEPT_(__node_alloc_traits::propagate_on_container_move_assignment::value&&
743                     is_nothrow_move_assignable<__node_allocator>::value);
744
745  _LIBCPP_HIDE_FROM_ABI list& operator=(initializer_list<value_type> __il) {
746    assign(__il.begin(), __il.end());
747    return *this;
748  }
749
750  _LIBCPP_HIDE_FROM_ABI void assign(initializer_list<value_type> __il) { assign(__il.begin(), __il.end()); }
751#endif // _LIBCPP_CXX03_LANG
752
753  template <class _InpIter>
754  _LIBCPP_HIDE_FROM_ABI void
755  assign(_InpIter __f, _InpIter __l, __enable_if_t<__has_input_iterator_category<_InpIter>::value>* = 0);
756
757#if _LIBCPP_STD_VER >= 23
758  template <_ContainerCompatibleRange<_Tp> _Range>
759  _LIBCPP_HIDE_FROM_ABI void assign_range(_Range&& __range) {
760    __assign_with_sentinel(ranges::begin(__range), ranges::end(__range));
761  }
762#endif
763
764  _LIBCPP_HIDE_FROM_ABI void assign(size_type __n, const value_type& __x);
765
766  _LIBCPP_HIDE_FROM_ABI allocator_type get_allocator() const _NOEXCEPT;
767
768  _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return base::__sz(); }
769  _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return base::empty(); }
770  _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT {
771    return std::min<size_type>(base::__node_alloc_max_size(), numeric_limits<difference_type >::max());
772  }
773
774  _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return base::begin(); }
775  _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return base::begin(); }
776  _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return base::end(); }
777  _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return base::end(); }
778  _LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT { return base::begin(); }
779  _LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT { return base::end(); }
780
781  _LIBCPP_HIDE_FROM_ABI reverse_iterator rbegin() _NOEXCEPT { return reverse_iterator(end()); }
782  _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rbegin() const _NOEXCEPT { return const_reverse_iterator(end()); }
783  _LIBCPP_HIDE_FROM_ABI reverse_iterator rend() _NOEXCEPT { return reverse_iterator(begin()); }
784  _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rend() const _NOEXCEPT { return const_reverse_iterator(begin()); }
785  _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crbegin() const _NOEXCEPT { return const_reverse_iterator(end()); }
786  _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crend() const _NOEXCEPT { return const_reverse_iterator(begin()); }
787
788  _LIBCPP_HIDE_FROM_ABI reference front() {
789    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "list::front called on empty list");
790    return base::__end_.__next_->__as_node()->__get_value();
791  }
792  _LIBCPP_HIDE_FROM_ABI const_reference front() const {
793    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "list::front called on empty list");
794    return base::__end_.__next_->__as_node()->__get_value();
795  }
796  _LIBCPP_HIDE_FROM_ABI reference back() {
797    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "list::back called on empty list");
798    return base::__end_.__prev_->__as_node()->__get_value();
799  }
800  _LIBCPP_HIDE_FROM_ABI const_reference back() const {
801    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "list::back called on empty list");
802    return base::__end_.__prev_->__as_node()->__get_value();
803  }
804
805#ifndef _LIBCPP_CXX03_LANG
806  _LIBCPP_HIDE_FROM_ABI void push_front(value_type&& __x);
807  _LIBCPP_HIDE_FROM_ABI void push_back(value_type&& __x);
808
809#  if _LIBCPP_STD_VER >= 23
810  template <_ContainerCompatibleRange<_Tp> _Range>
811  _LIBCPP_HIDE_FROM_ABI void prepend_range(_Range&& __range) {
812    insert_range(begin(), std::forward<_Range>(__range));
813  }
814
815  template <_ContainerCompatibleRange<_Tp> _Range>
816  _LIBCPP_HIDE_FROM_ABI void append_range(_Range&& __range) {
817    insert_range(end(), std::forward<_Range>(__range));
818  }
819#  endif
820
821  template <class... _Args>
822#  if _LIBCPP_STD_VER >= 17
823  _LIBCPP_HIDE_FROM_ABI reference emplace_front(_Args&&... __args);
824#  else
825  _LIBCPP_HIDE_FROM_ABI void emplace_front(_Args&&... __args);
826#  endif
827  template <class... _Args>
828#  if _LIBCPP_STD_VER >= 17
829  _LIBCPP_HIDE_FROM_ABI reference emplace_back(_Args&&... __args);
830#  else
831  _LIBCPP_HIDE_FROM_ABI void emplace_back(_Args&&... __args);
832#  endif
833  template <class... _Args>
834  _LIBCPP_HIDE_FROM_ABI iterator emplace(const_iterator __p, _Args&&... __args);
835
836  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, value_type&& __x);
837
838  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, initializer_list<value_type> __il) {
839    return insert(__p, __il.begin(), __il.end());
840  }
841#endif // _LIBCPP_CXX03_LANG
842
843  _LIBCPP_HIDE_FROM_ABI void push_front(const value_type& __x);
844  _LIBCPP_HIDE_FROM_ABI void push_back(const value_type& __x);
845
846#ifndef _LIBCPP_CXX03_LANG
847  template <class _Arg>
848  _LIBCPP_HIDE_FROM_ABI void __emplace_back(_Arg&& __arg) {
849    emplace_back(std::forward<_Arg>(__arg));
850  }
851#else
852  _LIBCPP_HIDE_FROM_ABI void __emplace_back(value_type const& __arg) { push_back(__arg); }
853#endif
854
855  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, const value_type& __x);
856  _LIBCPP_HIDE_FROM_ABI iterator insert(const_iterator __p, size_type __n, const value_type& __x);
857  template <class _InpIter>
858  _LIBCPP_HIDE_FROM_ABI iterator
859  insert(const_iterator __p,
860         _InpIter __f,
861         _InpIter __l,
862         __enable_if_t<__has_input_iterator_category<_InpIter>::value>* = 0);
863
864#if _LIBCPP_STD_VER >= 23
865  template <_ContainerCompatibleRange<_Tp> _Range>
866  _LIBCPP_HIDE_FROM_ABI iterator insert_range(const_iterator __position, _Range&& __range) {
867    return __insert_with_sentinel(__position, ranges::begin(__range), ranges::end(__range));
868  }
869#endif
870
871  _LIBCPP_HIDE_FROM_ABI void swap(list& __c)
872#if _LIBCPP_STD_VER >= 14
873      _NOEXCEPT
874#else
875      _NOEXCEPT_(!__node_alloc_traits::propagate_on_container_swap::value ||
876                 __is_nothrow_swappable<__node_allocator>::value)
877#endif
878  {
879    base::swap(__c);
880  }
881  _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT { base::clear(); }
882
883  _LIBCPP_HIDE_FROM_ABI void pop_front();
884  _LIBCPP_HIDE_FROM_ABI void pop_back();
885
886  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __p);
887  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __f, const_iterator __l);
888
889  _LIBCPP_HIDE_FROM_ABI void resize(size_type __n);
890  _LIBCPP_HIDE_FROM_ABI void resize(size_type __n, const value_type& __x);
891
892  _LIBCPP_HIDE_FROM_ABI void splice(const_iterator __p, list& __c);
893#ifndef _LIBCPP_CXX03_LANG
894  _LIBCPP_HIDE_FROM_ABI void splice(const_iterator __p, list&& __c) { splice(__p, __c); }
895  _LIBCPP_HIDE_FROM_ABI void splice(const_iterator __p, list&& __c, const_iterator __i) { splice(__p, __c, __i); }
896  _LIBCPP_HIDE_FROM_ABI void splice(const_iterator __p, list&& __c, const_iterator __f, const_iterator __l) {
897    splice(__p, __c, __f, __l);
898  }
899#endif
900  _LIBCPP_HIDE_FROM_ABI void splice(const_iterator __p, list& __c, const_iterator __i);
901  _LIBCPP_HIDE_FROM_ABI void splice(const_iterator __p, list& __c, const_iterator __f, const_iterator __l);
902
903  _LIBCPP_HIDE_FROM_ABI __remove_return_type remove(const value_type& __x);
904  template <class _Pred>
905  _LIBCPP_HIDE_FROM_ABI __remove_return_type remove_if(_Pred __pred);
906  _LIBCPP_HIDE_FROM_ABI __remove_return_type unique() { return unique(__equal_to()); }
907  template <class _BinaryPred>
908  _LIBCPP_HIDE_FROM_ABI __remove_return_type unique(_BinaryPred __binary_pred);
909  _LIBCPP_HIDE_FROM_ABI void merge(list& __c);
910#ifndef _LIBCPP_CXX03_LANG
911  _LIBCPP_HIDE_FROM_ABI void merge(list&& __c) { merge(__c); }
912
913  template <class _Comp>
914  _LIBCPP_HIDE_FROM_ABI void merge(list&& __c, _Comp __comp) {
915    merge(__c, __comp);
916  }
917#endif
918  template <class _Comp>
919  _LIBCPP_HIDE_FROM_ABI void merge(list& __c, _Comp __comp);
920
921  _LIBCPP_HIDE_FROM_ABI void sort();
922  template <class _Comp>
923  _LIBCPP_HIDE_FROM_ABI void sort(_Comp __comp);
924
925  _LIBCPP_HIDE_FROM_ABI void reverse() _NOEXCEPT;
926
927  _LIBCPP_HIDE_FROM_ABI bool __invariants() const;
928
929private:
930  template <class _Iterator, class _Sentinel>
931  _LIBCPP_HIDE_FROM_ABI void __assign_with_sentinel(_Iterator __f, _Sentinel __l);
932
933  template <class _Iterator, class _Sentinel>
934  _LIBCPP_HIDE_FROM_ABI iterator __insert_with_sentinel(const_iterator __p, _Iterator __f, _Sentinel __l);
935
936  _LIBCPP_HIDE_FROM_ABI static void __link_nodes(__link_pointer __p, __link_pointer __f, __link_pointer __l);
937  _LIBCPP_HIDE_FROM_ABI void __link_nodes_at_front(__link_pointer __f, __link_pointer __l);
938  _LIBCPP_HIDE_FROM_ABI void __link_nodes_at_back(__link_pointer __f, __link_pointer __l);
939  _LIBCPP_HIDE_FROM_ABI iterator __iterator(size_type __n);
940  // TODO: Make this _LIBCPP_HIDE_FROM_ABI
941  template <class _Comp>
942  _LIBCPP_HIDDEN static iterator __sort(iterator __f1, iterator __e2, size_type __n, _Comp& __comp);
943
944  _LIBCPP_HIDE_FROM_ABI void __move_assign(list& __c, true_type)
945      _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value);
946  _LIBCPP_HIDE_FROM_ABI void __move_assign(list& __c, false_type);
947};
948
949#if _LIBCPP_STD_VER >= 17
950template <class _InputIterator,
951          class _Alloc = allocator<__iter_value_type<_InputIterator>>,
952          class        = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
953          class        = enable_if_t<__is_allocator<_Alloc>::value> >
954list(_InputIterator, _InputIterator) -> list<__iter_value_type<_InputIterator>, _Alloc>;
955
956template <class _InputIterator,
957          class _Alloc,
958          class = enable_if_t<__has_input_iterator_category<_InputIterator>::value>,
959          class = enable_if_t<__is_allocator<_Alloc>::value> >
960list(_InputIterator, _InputIterator, _Alloc) -> list<__iter_value_type<_InputIterator>, _Alloc>;
961#endif
962
963#if _LIBCPP_STD_VER >= 23
964template <ranges::input_range _Range,
965          class _Alloc = allocator<ranges::range_value_t<_Range>>,
966          class        = enable_if_t<__is_allocator<_Alloc>::value> >
967list(from_range_t, _Range&&, _Alloc = _Alloc()) -> list<ranges::range_value_t<_Range>, _Alloc>;
968#endif
969
970// Link in nodes [__f, __l] just prior to __p
971template <class _Tp, class _Alloc>
972inline void list<_Tp, _Alloc>::__link_nodes(__link_pointer __p, __link_pointer __f, __link_pointer __l) {
973  __p->__prev_->__next_ = __f;
974  __f->__prev_          = __p->__prev_;
975  __p->__prev_          = __l;
976  __l->__next_          = __p;
977}
978
979// Link in nodes [__f, __l] at the front of the list
980template <class _Tp, class _Alloc>
981inline void list<_Tp, _Alloc>::__link_nodes_at_front(__link_pointer __f, __link_pointer __l) {
982  __f->__prev_          = base::__end_as_link();
983  __l->__next_          = base::__end_.__next_;
984  __l->__next_->__prev_ = __l;
985  base::__end_.__next_  = __f;
986}
987
988// Link in nodes [__f, __l] at the back of the list
989template <class _Tp, class _Alloc>
990inline void list<_Tp, _Alloc>::__link_nodes_at_back(__link_pointer __f, __link_pointer __l) {
991  __l->__next_          = base::__end_as_link();
992  __f->__prev_          = base::__end_.__prev_;
993  __f->__prev_->__next_ = __f;
994  base::__end_.__prev_  = __l;
995}
996
997template <class _Tp, class _Alloc>
998inline typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::__iterator(size_type __n) {
999  return __n <= base::__sz() / 2 ? std::next(begin(), __n) : std::prev(end(), base::__sz() - __n);
1000}
1001
1002template <class _Tp, class _Alloc>
1003list<_Tp, _Alloc>::list(size_type __n) {
1004  for (; __n > 0; --__n)
1005#ifndef _LIBCPP_CXX03_LANG
1006    emplace_back();
1007#else
1008    push_back(value_type());
1009#endif
1010}
1011
1012#if _LIBCPP_STD_VER >= 14
1013template <class _Tp, class _Alloc>
1014list<_Tp, _Alloc>::list(size_type __n, const allocator_type& __a) : base(__a) {
1015  for (; __n > 0; --__n)
1016    emplace_back();
1017}
1018#endif
1019
1020template <class _Tp, class _Alloc>
1021list<_Tp, _Alloc>::list(size_type __n, const value_type& __x) {
1022  for (; __n > 0; --__n)
1023    push_back(__x);
1024}
1025
1026template <class _Tp, class _Alloc>
1027template <class _InpIter>
1028list<_Tp, _Alloc>::list(_InpIter __f, _InpIter __l, __enable_if_t<__has_input_iterator_category<_InpIter>::value>*) {
1029  for (; __f != __l; ++__f)
1030    __emplace_back(*__f);
1031}
1032
1033template <class _Tp, class _Alloc>
1034template <class _InpIter>
1035list<_Tp, _Alloc>::list(_InpIter __f,
1036                        _InpIter __l,
1037                        const allocator_type& __a,
1038                        __enable_if_t<__has_input_iterator_category<_InpIter>::value>*)
1039    : base(__a) {
1040  for (; __f != __l; ++__f)
1041    __emplace_back(*__f);
1042}
1043
1044template <class _Tp, class _Alloc>
1045list<_Tp, _Alloc>::list(const list& __c)
1046    : base(__node_alloc_traits::select_on_container_copy_construction(__c.__node_alloc())) {
1047  for (const_iterator __i = __c.begin(), __e = __c.end(); __i != __e; ++__i)
1048    push_back(*__i);
1049}
1050
1051template <class _Tp, class _Alloc>
1052list<_Tp, _Alloc>::list(const list& __c, const __type_identity_t<allocator_type>& __a) : base(__a) {
1053  for (const_iterator __i = __c.begin(), __e = __c.end(); __i != __e; ++__i)
1054    push_back(*__i);
1055}
1056
1057#ifndef _LIBCPP_CXX03_LANG
1058
1059template <class _Tp, class _Alloc>
1060list<_Tp, _Alloc>::list(initializer_list<value_type> __il, const allocator_type& __a) : base(__a) {
1061  for (typename initializer_list<value_type>::const_iterator __i = __il.begin(), __e = __il.end(); __i != __e; ++__i)
1062    push_back(*__i);
1063}
1064
1065template <class _Tp, class _Alloc>
1066list<_Tp, _Alloc>::list(initializer_list<value_type> __il) {
1067  for (typename initializer_list<value_type>::const_iterator __i = __il.begin(), __e = __il.end(); __i != __e; ++__i)
1068    push_back(*__i);
1069}
1070
1071template <class _Tp, class _Alloc>
1072inline list<_Tp, _Alloc>::list(list&& __c) _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value)
1073    : base(std::move(__c.__node_alloc())) {
1074  splice(end(), __c);
1075}
1076
1077template <class _Tp, class _Alloc>
1078inline list<_Tp, _Alloc>::list(list&& __c, const __type_identity_t<allocator_type>& __a) : base(__a) {
1079  if (__a == __c.get_allocator())
1080    splice(end(), __c);
1081  else {
1082    typedef move_iterator<iterator> _Ip;
1083    assign(_Ip(__c.begin()), _Ip(__c.end()));
1084  }
1085}
1086
1087template <class _Tp, class _Alloc>
1088inline list<_Tp, _Alloc>& list<_Tp, _Alloc>::operator=(list&& __c)
1089    _NOEXCEPT_(__node_alloc_traits::propagate_on_container_move_assignment::value&&
1090                   is_nothrow_move_assignable<__node_allocator>::value) {
1091  __move_assign(__c, integral_constant<bool, __node_alloc_traits::propagate_on_container_move_assignment::value>());
1092  return *this;
1093}
1094
1095template <class _Tp, class _Alloc>
1096void list<_Tp, _Alloc>::__move_assign(list& __c, false_type) {
1097  if (base::__node_alloc() != __c.__node_alloc()) {
1098    typedef move_iterator<iterator> _Ip;
1099    assign(_Ip(__c.begin()), _Ip(__c.end()));
1100  } else
1101    __move_assign(__c, true_type());
1102}
1103
1104template <class _Tp, class _Alloc>
1105void list<_Tp, _Alloc>::__move_assign(list& __c, true_type)
1106    _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value) {
1107  clear();
1108  base::__move_assign_alloc(__c);
1109  splice(end(), __c);
1110}
1111
1112#endif // _LIBCPP_CXX03_LANG
1113
1114template <class _Tp, class _Alloc>
1115inline list<_Tp, _Alloc>& list<_Tp, _Alloc>::operator=(const list& __c) {
1116  if (this != std::addressof(__c)) {
1117    base::__copy_assign_alloc(__c);
1118    assign(__c.begin(), __c.end());
1119  }
1120  return *this;
1121}
1122
1123template <class _Tp, class _Alloc>
1124template <class _InpIter>
1125void list<_Tp, _Alloc>::assign(
1126    _InpIter __f, _InpIter __l, __enable_if_t<__has_input_iterator_category<_InpIter>::value>*) {
1127  __assign_with_sentinel(__f, __l);
1128}
1129
1130template <class _Tp, class _Alloc>
1131template <class _Iterator, class _Sentinel>
1132_LIBCPP_HIDE_FROM_ABI void list<_Tp, _Alloc>::__assign_with_sentinel(_Iterator __f, _Sentinel __l) {
1133  iterator __i = begin();
1134  iterator __e = end();
1135  for (; __f != __l && __i != __e; ++__f, (void)++__i)
1136    *__i = *__f;
1137  if (__i == __e)
1138    __insert_with_sentinel(__e, std::move(__f), std::move(__l));
1139  else
1140    erase(__i, __e);
1141}
1142
1143template <class _Tp, class _Alloc>
1144void list<_Tp, _Alloc>::assign(size_type __n, const value_type& __x) {
1145  iterator __i = begin();
1146  iterator __e = end();
1147  for (; __n > 0 && __i != __e; --__n, (void)++__i)
1148    *__i = __x;
1149  if (__i == __e)
1150    insert(__e, __n, __x);
1151  else
1152    erase(__i, __e);
1153}
1154
1155template <class _Tp, class _Alloc>
1156inline _Alloc list<_Tp, _Alloc>::get_allocator() const _NOEXCEPT {
1157  return allocator_type(base::__node_alloc());
1158}
1159
1160template <class _Tp, class _Alloc>
1161typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::insert(const_iterator __p, const value_type& __x) {
1162  __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, __x);
1163  __link_nodes(__p.__ptr_, __node->__as_link(), __node->__as_link());
1164  ++base::__sz();
1165  return iterator(__node->__as_link());
1166}
1167
1168template <class _Tp, class _Alloc>
1169typename list<_Tp, _Alloc>::iterator
1170list<_Tp, _Alloc>::insert(const_iterator __p, size_type __n, const value_type& __x) {
1171  iterator __r(__p.__ptr_);
1172  if (__n > 0) {
1173    size_type __ds        = 0;
1174    __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, __x);
1175    ++__ds;
1176    __r          = iterator(__node->__as_link());
1177    iterator __e = __r;
1178#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1179    try {
1180#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1181      for (--__n; __n != 0; --__n, (void)++__e, ++__ds) {
1182        __e.__ptr_->__next_ = this->__create_node(/* prev = */ __e.__ptr_, /* next = */ nullptr, __x)->__as_link();
1183      }
1184#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1185    } catch (...) {
1186      while (true) {
1187        __link_pointer __prev    = __e.__ptr_->__prev_;
1188        __node_pointer __current = __e.__ptr_->__as_node();
1189        this->__delete_node(__current);
1190        if (__prev == 0)
1191          break;
1192        __e = iterator(__prev);
1193      }
1194      throw;
1195    }
1196#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1197    __link_nodes(__p.__ptr_, __r.__ptr_, __e.__ptr_);
1198    base::__sz() += __ds;
1199  }
1200  return __r;
1201}
1202
1203template <class _Tp, class _Alloc>
1204template <class _InpIter>
1205typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::insert(
1206    const_iterator __p, _InpIter __f, _InpIter __l, __enable_if_t<__has_input_iterator_category<_InpIter>::value>*) {
1207  return __insert_with_sentinel(__p, __f, __l);
1208}
1209
1210template <class _Tp, class _Alloc>
1211template <class _Iterator, class _Sentinel>
1212_LIBCPP_HIDE_FROM_ABI typename list<_Tp, _Alloc>::iterator
1213list<_Tp, _Alloc>::__insert_with_sentinel(const_iterator __p, _Iterator __f, _Sentinel __l) {
1214  iterator __r(__p.__ptr_);
1215  if (__f != __l) {
1216    size_type __ds        = 0;
1217    __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, *__f);
1218    ++__ds;
1219    __r          = iterator(__node->__as_link());
1220    iterator __e = __r;
1221#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1222    try {
1223#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1224      for (++__f; __f != __l; ++__f, (void)++__e, ++__ds) {
1225        __e.__ptr_->__next_ = this->__create_node(/* prev = */ __e.__ptr_, /* next = */ nullptr, *__f)->__as_link();
1226      }
1227#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1228    } catch (...) {
1229      while (true) {
1230        __link_pointer __prev    = __e.__ptr_->__prev_;
1231        __node_pointer __current = __e.__ptr_->__as_node();
1232        this->__delete_node(__current);
1233        if (__prev == 0)
1234          break;
1235        __e = iterator(__prev);
1236      }
1237      throw;
1238    }
1239#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1240    __link_nodes(__p.__ptr_, __r.__ptr_, __e.__ptr_);
1241    base::__sz() += __ds;
1242  }
1243  return __r;
1244}
1245
1246template <class _Tp, class _Alloc>
1247void list<_Tp, _Alloc>::push_front(const value_type& __x) {
1248  __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, __x);
1249  __link_pointer __nl   = __node->__as_link();
1250  __link_nodes_at_front(__nl, __nl);
1251  ++base::__sz();
1252}
1253
1254template <class _Tp, class _Alloc>
1255void list<_Tp, _Alloc>::push_back(const value_type& __x) {
1256  __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, __x);
1257  __link_pointer __nl   = __node->__as_link();
1258  __link_nodes_at_back(__nl, __nl);
1259  ++base::__sz();
1260}
1261
1262#ifndef _LIBCPP_CXX03_LANG
1263
1264template <class _Tp, class _Alloc>
1265void list<_Tp, _Alloc>::push_front(value_type&& __x) {
1266  __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, std::move(__x));
1267  __link_pointer __nl   = __node->__as_link();
1268  __link_nodes_at_front(__nl, __nl);
1269  ++base::__sz();
1270}
1271
1272template <class _Tp, class _Alloc>
1273void list<_Tp, _Alloc>::push_back(value_type&& __x) {
1274  __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, std::move(__x));
1275  __link_pointer __nl   = __node->__as_link();
1276  __link_nodes_at_back(__nl, __nl);
1277  ++base::__sz();
1278}
1279
1280template <class _Tp, class _Alloc>
1281template <class... _Args>
1282#  if _LIBCPP_STD_VER >= 17
1283typename list<_Tp, _Alloc>::reference
1284#  else
1285void
1286#  endif
1287list<_Tp, _Alloc>::emplace_front(_Args&&... __args) {
1288  __node_pointer __node =
1289      this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, std::forward<_Args>(__args)...);
1290  __link_pointer __nl = __node->__as_link();
1291  __link_nodes_at_front(__nl, __nl);
1292  ++base::__sz();
1293#  if _LIBCPP_STD_VER >= 17
1294  return __node->__get_value();
1295#  endif
1296}
1297
1298template <class _Tp, class _Alloc>
1299template <class... _Args>
1300#  if _LIBCPP_STD_VER >= 17
1301typename list<_Tp, _Alloc>::reference
1302#  else
1303void
1304#  endif
1305list<_Tp, _Alloc>::emplace_back(_Args&&... __args) {
1306  __node_pointer __node =
1307      this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, std::forward<_Args>(__args)...);
1308  __link_pointer __nl = __node->__as_link();
1309  __link_nodes_at_back(__nl, __nl);
1310  ++base::__sz();
1311#  if _LIBCPP_STD_VER >= 17
1312  return __node->__get_value();
1313#  endif
1314}
1315
1316template <class _Tp, class _Alloc>
1317template <class... _Args>
1318typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::emplace(const_iterator __p, _Args&&... __args) {
1319  __node_pointer __node =
1320      this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, std::forward<_Args>(__args)...);
1321  __link_pointer __nl = __node->__as_link();
1322  __link_nodes(__p.__ptr_, __nl, __nl);
1323  ++base::__sz();
1324  return iterator(__nl);
1325}
1326
1327template <class _Tp, class _Alloc>
1328typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::insert(const_iterator __p, value_type&& __x) {
1329  __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, std::move(__x));
1330  __link_pointer __nl   = __node->__as_link();
1331  __link_nodes(__p.__ptr_, __nl, __nl);
1332  ++base::__sz();
1333  return iterator(__nl);
1334}
1335
1336#endif // _LIBCPP_CXX03_LANG
1337
1338template <class _Tp, class _Alloc>
1339void list<_Tp, _Alloc>::pop_front() {
1340  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "list::pop_front() called with empty list");
1341  __link_pointer __n = base::__end_.__next_;
1342  base::__unlink_nodes(__n, __n);
1343  --base::__sz();
1344  this->__delete_node(__n->__as_node());
1345}
1346
1347template <class _Tp, class _Alloc>
1348void list<_Tp, _Alloc>::pop_back() {
1349  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "list::pop_back() called on an empty list");
1350  __link_pointer __n = base::__end_.__prev_;
1351  base::__unlink_nodes(__n, __n);
1352  --base::__sz();
1353  this->__delete_node(__n->__as_node());
1354}
1355
1356template <class _Tp, class _Alloc>
1357typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::erase(const_iterator __p) {
1358  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__p != end(), "list::erase(iterator) called with a non-dereferenceable iterator");
1359  __link_pointer __n = __p.__ptr_;
1360  __link_pointer __r = __n->__next_;
1361  base::__unlink_nodes(__n, __n);
1362  --base::__sz();
1363  this->__delete_node(__n->__as_node());
1364  return iterator(__r);
1365}
1366
1367template <class _Tp, class _Alloc>
1368typename list<_Tp, _Alloc>::iterator list<_Tp, _Alloc>::erase(const_iterator __f, const_iterator __l) {
1369  if (__f != __l) {
1370    base::__unlink_nodes(__f.__ptr_, __l.__ptr_->__prev_);
1371    while (__f != __l) {
1372      __link_pointer __n = __f.__ptr_;
1373      ++__f;
1374      --base::__sz();
1375      this->__delete_node(__n->__as_node());
1376    }
1377  }
1378  return iterator(__l.__ptr_);
1379}
1380
1381template <class _Tp, class _Alloc>
1382void list<_Tp, _Alloc>::resize(size_type __n) {
1383  if (__n < base::__sz())
1384    erase(__iterator(__n), end());
1385  else if (__n > base::__sz()) {
1386    __n -= base::__sz();
1387    size_type __ds        = 0;
1388    __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr);
1389    ++__ds;
1390    iterator __r = iterator(__node->__as_link());
1391    iterator __e = __r;
1392#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1393    try {
1394#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1395      for (--__n; __n != 0; --__n, (void)++__e, ++__ds) {
1396        __e.__ptr_->__next_ = this->__create_node(/* prev = */ __e.__ptr_, /* next = */ nullptr)->__as_link();
1397      }
1398#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1399    } catch (...) {
1400      while (true) {
1401        __link_pointer __prev    = __e.__ptr_->__prev_;
1402        __node_pointer __current = __e.__ptr_->__as_node();
1403        this->__delete_node(__current);
1404        if (__prev == 0)
1405          break;
1406        __e = iterator(__prev);
1407      }
1408      throw;
1409    }
1410#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1411    __link_nodes_at_back(__r.__ptr_, __e.__ptr_);
1412    base::__sz() += __ds;
1413  }
1414}
1415
1416template <class _Tp, class _Alloc>
1417void list<_Tp, _Alloc>::resize(size_type __n, const value_type& __x) {
1418  if (__n < base::__sz())
1419    erase(__iterator(__n), end());
1420  else if (__n > base::__sz()) {
1421    __n -= base::__sz();
1422    size_type __ds        = 0;
1423    __node_pointer __node = this->__create_node(/* prev = */ nullptr, /* next = */ nullptr, __x);
1424    ++__ds;
1425    __link_pointer __nl = __node->__as_link();
1426    iterator __r        = iterator(__nl);
1427    iterator __e        = __r;
1428#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1429    try {
1430#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1431      for (--__n; __n != 0; --__n, (void)++__e, ++__ds) {
1432        __e.__ptr_->__next_ = this->__create_node(/* prev = */ __e.__ptr_, /* next = */ nullptr, __x)->__as_link();
1433      }
1434#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1435    } catch (...) {
1436      while (true) {
1437        __link_pointer __prev    = __e.__ptr_->__prev_;
1438        __node_pointer __current = __e.__ptr_->__as_node();
1439        this->__delete_node(__current);
1440        if (__prev == 0)
1441          break;
1442        __e = iterator(__prev);
1443      }
1444      throw;
1445    }
1446#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1447    __link_nodes(base::__end_as_link(), __r.__ptr_, __e.__ptr_);
1448    base::__sz() += __ds;
1449  }
1450}
1451
1452template <class _Tp, class _Alloc>
1453void list<_Tp, _Alloc>::splice(const_iterator __p, list& __c) {
1454  _LIBCPP_ASSERT_VALID_INPUT_RANGE(
1455      this != std::addressof(__c), "list::splice(iterator, list) called with this == &list");
1456  if (!__c.empty()) {
1457    __link_pointer __f = __c.__end_.__next_;
1458    __link_pointer __l = __c.__end_.__prev_;
1459    base::__unlink_nodes(__f, __l);
1460    __link_nodes(__p.__ptr_, __f, __l);
1461    base::__sz() += __c.__sz();
1462    __c.__sz() = 0;
1463  }
1464}
1465
1466template <class _Tp, class _Alloc>
1467void list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __i) {
1468  if (__p.__ptr_ != __i.__ptr_ && __p.__ptr_ != __i.__ptr_->__next_) {
1469    __link_pointer __f = __i.__ptr_;
1470    base::__unlink_nodes(__f, __f);
1471    __link_nodes(__p.__ptr_, __f, __f);
1472    --__c.__sz();
1473    ++base::__sz();
1474  }
1475}
1476
1477template <class _Tp, class _Alloc>
1478void list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __f, const_iterator __l) {
1479  if (__f != __l) {
1480    __link_pointer __first = __f.__ptr_;
1481    --__l;
1482    __link_pointer __last = __l.__ptr_;
1483    if (this != std::addressof(__c)) {
1484      size_type __s = std::distance(__f, __l) + 1;
1485      __c.__sz() -= __s;
1486      base::__sz() += __s;
1487    }
1488    base::__unlink_nodes(__first, __last);
1489    __link_nodes(__p.__ptr_, __first, __last);
1490  }
1491}
1492
1493template <class _Tp, class _Alloc>
1494typename list<_Tp, _Alloc>::__remove_return_type list<_Tp, _Alloc>::remove(const value_type& __x) {
1495  list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
1496  for (const_iterator __i = begin(), __e = end(); __i != __e;) {
1497    if (*__i == __x) {
1498      const_iterator __j = std::next(__i);
1499      for (; __j != __e && *__j == __x; ++__j)
1500        ;
1501      __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
1502      __i = __j;
1503      if (__i != __e)
1504        ++__i;
1505    } else
1506      ++__i;
1507  }
1508
1509  return (__remove_return_type)__deleted_nodes.size();
1510}
1511
1512template <class _Tp, class _Alloc>
1513template <class _Pred>
1514typename list<_Tp, _Alloc>::__remove_return_type list<_Tp, _Alloc>::remove_if(_Pred __pred) {
1515  list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
1516  for (iterator __i = begin(), __e = end(); __i != __e;) {
1517    if (__pred(*__i)) {
1518      iterator __j = std::next(__i);
1519      for (; __j != __e && __pred(*__j); ++__j)
1520        ;
1521      __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
1522      __i = __j;
1523      if (__i != __e)
1524        ++__i;
1525    } else
1526      ++__i;
1527  }
1528
1529  return (__remove_return_type)__deleted_nodes.size();
1530}
1531
1532template <class _Tp, class _Alloc>
1533template <class _BinaryPred>
1534typename list<_Tp, _Alloc>::__remove_return_type list<_Tp, _Alloc>::unique(_BinaryPred __binary_pred) {
1535  list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
1536  for (iterator __i = begin(), __e = end(); __i != __e;) {
1537    iterator __j = std::next(__i);
1538    for (; __j != __e && __binary_pred(*__i, *__j); ++__j)
1539      ;
1540    if (++__i != __j) {
1541      __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
1542      __i = __j;
1543    }
1544  }
1545
1546  return (__remove_return_type)__deleted_nodes.size();
1547}
1548
1549template <class _Tp, class _Alloc>
1550inline void list<_Tp, _Alloc>::merge(list& __c) {
1551  merge(__c, __less<>());
1552}
1553
1554template <class _Tp, class _Alloc>
1555template <class _Comp>
1556void list<_Tp, _Alloc>::merge(list& __c, _Comp __comp) {
1557  if (this != std::addressof(__c)) {
1558    iterator __f1 = begin();
1559    iterator __e1 = end();
1560    iterator __f2 = __c.begin();
1561    iterator __e2 = __c.end();
1562    while (__f1 != __e1 && __f2 != __e2) {
1563      if (__comp(*__f2, *__f1)) {
1564        size_type __ds = 1;
1565        iterator __m2  = std::next(__f2);
1566        for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2, (void)++__ds)
1567          ;
1568        base::__sz() += __ds;
1569        __c.__sz() -= __ds;
1570        __link_pointer __f = __f2.__ptr_;
1571        __link_pointer __l = __m2.__ptr_->__prev_;
1572        __f2               = __m2;
1573        base::__unlink_nodes(__f, __l);
1574        __m2 = std::next(__f1);
1575        __link_nodes(__f1.__ptr_, __f, __l);
1576        __f1 = __m2;
1577      } else
1578        ++__f1;
1579    }
1580    splice(__e1, __c);
1581  }
1582}
1583
1584template <class _Tp, class _Alloc>
1585inline void list<_Tp, _Alloc>::sort() {
1586  sort(__less<>());
1587}
1588
1589template <class _Tp, class _Alloc>
1590template <class _Comp>
1591inline void list<_Tp, _Alloc>::sort(_Comp __comp) {
1592  __sort(begin(), end(), base::__sz(), __comp);
1593}
1594
1595template <class _Tp, class _Alloc>
1596template <class _Comp>
1597typename list<_Tp, _Alloc>::iterator
1598list<_Tp, _Alloc>::__sort(iterator __f1, iterator __e2, size_type __n, _Comp& __comp) {
1599  switch (__n) {
1600  case 0:
1601  case 1:
1602    return __f1;
1603  case 2:
1604    if (__comp(*--__e2, *__f1)) {
1605      __link_pointer __f = __e2.__ptr_;
1606      base::__unlink_nodes(__f, __f);
1607      __link_nodes(__f1.__ptr_, __f, __f);
1608      return __e2;
1609    }
1610    return __f1;
1611  }
1612  size_type __n2 = __n / 2;
1613  iterator __e1  = std::next(__f1, __n2);
1614  iterator __r = __f1 = __sort(__f1, __e1, __n2, __comp);
1615  iterator __f2 = __e1 = __sort(__e1, __e2, __n - __n2, __comp);
1616  if (__comp(*__f2, *__f1)) {
1617    iterator __m2 = std::next(__f2);
1618    for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2)
1619      ;
1620    __link_pointer __f = __f2.__ptr_;
1621    __link_pointer __l = __m2.__ptr_->__prev_;
1622    __r                = __f2;
1623    __e1 = __f2 = __m2;
1624    base::__unlink_nodes(__f, __l);
1625    __m2 = std::next(__f1);
1626    __link_nodes(__f1.__ptr_, __f, __l);
1627    __f1 = __m2;
1628  } else
1629    ++__f1;
1630  while (__f1 != __e1 && __f2 != __e2) {
1631    if (__comp(*__f2, *__f1)) {
1632      iterator __m2 = std::next(__f2);
1633      for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2)
1634        ;
1635      __link_pointer __f = __f2.__ptr_;
1636      __link_pointer __l = __m2.__ptr_->__prev_;
1637      if (__e1 == __f2)
1638        __e1 = __m2;
1639      __f2 = __m2;
1640      base::__unlink_nodes(__f, __l);
1641      __m2 = std::next(__f1);
1642      __link_nodes(__f1.__ptr_, __f, __l);
1643      __f1 = __m2;
1644    } else
1645      ++__f1;
1646  }
1647  return __r;
1648}
1649
1650template <class _Tp, class _Alloc>
1651void list<_Tp, _Alloc>::reverse() _NOEXCEPT {
1652  if (base::__sz() > 1) {
1653    iterator __e = end();
1654    for (iterator __i = begin(); __i.__ptr_ != __e.__ptr_;) {
1655      std::swap(__i.__ptr_->__prev_, __i.__ptr_->__next_);
1656      __i.__ptr_ = __i.__ptr_->__prev_;
1657    }
1658    std::swap(__e.__ptr_->__prev_, __e.__ptr_->__next_);
1659  }
1660}
1661
1662template <class _Tp, class _Alloc>
1663bool list<_Tp, _Alloc>::__invariants() const {
1664  return size() == std::distance(begin(), end());
1665}
1666
1667template <class _Tp, class _Alloc>
1668inline _LIBCPP_HIDE_FROM_ABI bool operator==(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y) {
1669  return __x.size() == __y.size() && std::equal(__x.begin(), __x.end(), __y.begin());
1670}
1671
1672#if _LIBCPP_STD_VER <= 17
1673
1674template <class _Tp, class _Alloc>
1675inline _LIBCPP_HIDE_FROM_ABI bool operator<(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y) {
1676  return std::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
1677}
1678
1679template <class _Tp, class _Alloc>
1680inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y) {
1681  return !(__x == __y);
1682}
1683
1684template <class _Tp, class _Alloc>
1685inline _LIBCPP_HIDE_FROM_ABI bool operator>(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y) {
1686  return __y < __x;
1687}
1688
1689template <class _Tp, class _Alloc>
1690inline _LIBCPP_HIDE_FROM_ABI bool operator>=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y) {
1691  return !(__x < __y);
1692}
1693
1694template <class _Tp, class _Alloc>
1695inline _LIBCPP_HIDE_FROM_ABI bool operator<=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y) {
1696  return !(__y < __x);
1697}
1698
1699#else // _LIBCPP_STD_VER <= 17
1700
1701template <class _Tp, class _Allocator>
1702_LIBCPP_HIDE_FROM_ABI __synth_three_way_result<_Tp>
1703operator<=>(const list<_Tp, _Allocator>& __x, const list<_Tp, _Allocator>& __y) {
1704  return std::lexicographical_compare_three_way(
1705      __x.begin(), __x.end(), __y.begin(), __y.end(), std::__synth_three_way<_Tp, _Tp>);
1706}
1707
1708#endif // _LIBCPP_STD_VER <= 17
1709
1710template <class _Tp, class _Alloc>
1711inline _LIBCPP_HIDE_FROM_ABI void swap(list<_Tp, _Alloc>& __x, list<_Tp, _Alloc>& __y)
1712    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
1713  __x.swap(__y);
1714}
1715
1716#if _LIBCPP_STD_VER >= 20
1717template <class _Tp, class _Allocator, class _Predicate>
1718inline _LIBCPP_HIDE_FROM_ABI typename list<_Tp, _Allocator>::size_type
1719erase_if(list<_Tp, _Allocator>& __c, _Predicate __pred) {
1720  return __c.remove_if(__pred);
1721}
1722
1723template <class _Tp, class _Allocator, class _Up>
1724inline _LIBCPP_HIDE_FROM_ABI typename list<_Tp, _Allocator>::size_type
1725erase(list<_Tp, _Allocator>& __c, const _Up& __v) {
1726  return std::erase_if(__c, [&](auto& __elem) { return __elem == __v; });
1727}
1728
1729template <>
1730inline constexpr bool __format::__enable_insertable<std::list<char>> = true;
1731#  ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
1732template <>
1733inline constexpr bool __format::__enable_insertable<std::list<wchar_t>> = true;
1734#  endif
1735
1736#endif // _LIBCPP_STD_VER >= 20
1737
1738_LIBCPP_END_NAMESPACE_STD
1739
1740#if _LIBCPP_STD_VER >= 17
1741_LIBCPP_BEGIN_NAMESPACE_STD
1742namespace pmr {
1743template <class _ValueT>
1744using list _LIBCPP_AVAILABILITY_PMR = std::list<_ValueT, polymorphic_allocator<_ValueT>>;
1745} // namespace pmr
1746_LIBCPP_END_NAMESPACE_STD
1747#endif
1748
1749_LIBCPP_POP_MACROS
1750
1751#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1752#  include <algorithm>
1753#  include <atomic>
1754#  include <concepts>
1755#  include <cstdint>
1756#  include <cstdlib>
1757#  include <functional>
1758#  include <iosfwd>
1759#  include <iterator>
1760#  include <stdexcept>
1761#  include <type_traits>
1762#  include <typeinfo>
1763#endif
1764
1765#endif // _LIBCPP_LIST
1766