xref: /freebsd/contrib/llvm-project/libcxx/include/list (revision 0eae32dcef82f6f06de6419a0d623d7def0cc8f6)
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    list(const list& x);
50    list(const list&, const allocator_type& a);
51    list(list&& x)
52        noexcept(is_nothrow_move_constructible<allocator_type>::value);
53    list(list&&, const allocator_type& a);
54    list(initializer_list<value_type>);
55    list(initializer_list<value_type>, const allocator_type& a);
56
57    ~list();
58
59    list& operator=(const list& x);
60    list& operator=(list&& x)
61        noexcept(
62             allocator_type::propagate_on_container_move_assignment::value &&
63             is_nothrow_move_assignable<allocator_type>::value);
64    list& operator=(initializer_list<value_type>);
65    template <class Iter>
66        void assign(Iter first, Iter last);
67    void assign(size_type n, const value_type& t);
68    void assign(initializer_list<value_type>);
69
70    allocator_type get_allocator() const noexcept;
71
72    iterator begin() noexcept;
73    const_iterator begin() const noexcept;
74    iterator end() noexcept;
75    const_iterator end() const noexcept;
76    reverse_iterator rbegin() noexcept;
77    const_reverse_iterator rbegin() const noexcept;
78    reverse_iterator rend() noexcept;
79    const_reverse_iterator rend() const noexcept;
80    const_iterator cbegin() const noexcept;
81    const_iterator cend() const noexcept;
82    const_reverse_iterator crbegin() const noexcept;
83    const_reverse_iterator crend() const noexcept;
84
85    reference front();
86    const_reference front() const;
87    reference back();
88    const_reference back() const;
89
90    bool empty() const noexcept;
91    size_type size() const noexcept;
92    size_type max_size() const noexcept;
93
94    template <class... Args>
95        reference emplace_front(Args&&... args); // reference in C++17
96    void pop_front();
97    template <class... Args>
98        reference emplace_back(Args&&... args);  // reference in C++17
99    void pop_back();
100    void push_front(const value_type& x);
101    void push_front(value_type&& x);
102    void push_back(const value_type& x);
103    void push_back(value_type&& x);
104    template <class... Args>
105        iterator emplace(const_iterator position, Args&&... args);
106    iterator insert(const_iterator position, const value_type& x);
107    iterator insert(const_iterator position, value_type&& x);
108    iterator insert(const_iterator position, size_type n, const value_type& x);
109    template <class Iter>
110        iterator insert(const_iterator position, Iter first, Iter last);
111    iterator insert(const_iterator position, initializer_list<value_type> il);
112
113    iterator erase(const_iterator position);
114    iterator erase(const_iterator position, const_iterator last);
115
116    void resize(size_type sz);
117    void resize(size_type sz, const value_type& c);
118
119    void swap(list&)
120        noexcept(allocator_traits<allocator_type>::is_always_equal::value);  // C++17
121    void clear() noexcept;
122
123    void splice(const_iterator position, list& x);
124    void splice(const_iterator position, list&& x);
125    void splice(const_iterator position, list& x, const_iterator i);
126    void splice(const_iterator position, list&& x, const_iterator i);
127    void splice(const_iterator position, list& x, const_iterator first,
128                                                  const_iterator last);
129    void splice(const_iterator position, list&& x, const_iterator first,
130                                                  const_iterator last);
131
132    size_type remove(const value_type& value);       // void before C++20
133    template <class Pred>
134      size_type remove_if(Pred pred);                // void before C++20
135    size_type unique();                              // void before C++20
136    template <class BinaryPredicate>
137      size_type unique(BinaryPredicate binary_pred); // void before C++20
138    void merge(list& x);
139    void merge(list&& x);
140    template <class Compare>
141        void merge(list& x, Compare comp);
142    template <class Compare>
143        void merge(list&& x, Compare comp);
144    void sort();
145    template <class Compare>
146        void sort(Compare comp);
147    void reverse() noexcept;
148};
149
150
151template <class InputIterator, class Allocator = allocator<typename iterator_traits<InputIterator>::value_type>>
152    list(InputIterator, InputIterator, Allocator = Allocator())
153    -> list<typename iterator_traits<InputIterator>::value_type, Allocator>;  // C++17
154
155template <class T, class Alloc>
156    bool operator==(const list<T,Alloc>& x, const list<T,Alloc>& y);
157template <class T, class Alloc>
158    bool operator< (const list<T,Alloc>& x, const list<T,Alloc>& y);
159template <class T, class Alloc>
160    bool operator!=(const list<T,Alloc>& x, const list<T,Alloc>& y);
161template <class T, class Alloc>
162    bool operator> (const list<T,Alloc>& x, const list<T,Alloc>& y);
163template <class T, class Alloc>
164    bool operator>=(const list<T,Alloc>& x, const list<T,Alloc>& y);
165template <class T, class Alloc>
166    bool operator<=(const list<T,Alloc>& x, const list<T,Alloc>& y);
167
168template <class T, class Alloc>
169    void swap(list<T,Alloc>& x, list<T,Alloc>& y)
170         noexcept(noexcept(x.swap(y)));
171
172template <class T, class Allocator, class U>
173    typename list<T, Allocator>::size_type
174    erase(list<T, Allocator>& c, const U& value);       // C++20
175template <class T, class Allocator, class Predicate>
176    typename list<T, Allocator>::size_type
177    erase_if(list<T, Allocator>& c, Predicate pred);    // C++20
178
179}  // std
180
181*/
182
183#include <__config>
184#include <__debug>
185#include <__utility/forward.h>
186#include <algorithm>
187#include <initializer_list>
188#include <iterator>
189#include <limits>
190#include <memory>
191#include <type_traits>
192#include <version>
193
194#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
195#pragma GCC system_header
196#endif
197
198_LIBCPP_PUSH_MACROS
199#include <__undef_macros>
200
201
202_LIBCPP_BEGIN_NAMESPACE_STD
203
204template <class _Tp, class _VoidPtr> struct __list_node;
205template <class _Tp, class _VoidPtr> struct __list_node_base;
206
207template <class _Tp, class _VoidPtr>
208struct __list_node_pointer_traits {
209  typedef typename __rebind_pointer<_VoidPtr, __list_node<_Tp, _VoidPtr> >::type
210        __node_pointer;
211  typedef typename __rebind_pointer<_VoidPtr, __list_node_base<_Tp, _VoidPtr> >::type
212        __base_pointer;
213
214#if defined(_LIBCPP_ABI_LIST_REMOVE_NODE_POINTER_UB)
215  typedef __base_pointer __link_pointer;
216#else
217  typedef typename conditional<
218          is_pointer<_VoidPtr>::value,
219          __base_pointer,
220          __node_pointer
221  >::type __link_pointer;
222#endif
223
224  typedef typename conditional<
225          is_same<__link_pointer, __node_pointer>::value,
226          __base_pointer,
227          __node_pointer
228  >::type __non_link_pointer;
229
230  static _LIBCPP_INLINE_VISIBILITY
231  __link_pointer __unsafe_link_pointer_cast(__link_pointer __p) {
232      return __p;
233  }
234
235  static _LIBCPP_INLINE_VISIBILITY
236  __link_pointer __unsafe_link_pointer_cast(__non_link_pointer __p) {
237      return static_cast<__link_pointer>(static_cast<_VoidPtr>(__p));
238  }
239
240};
241
242template <class _Tp, class _VoidPtr>
243struct __list_node_base
244{
245    typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
246    typedef typename _NodeTraits::__node_pointer __node_pointer;
247    typedef typename _NodeTraits::__base_pointer __base_pointer;
248    typedef typename _NodeTraits::__link_pointer __link_pointer;
249
250    __link_pointer __prev_;
251    __link_pointer __next_;
252
253    _LIBCPP_INLINE_VISIBILITY
254    __list_node_base() : __prev_(_NodeTraits::__unsafe_link_pointer_cast(__self())),
255                         __next_(_NodeTraits::__unsafe_link_pointer_cast(__self())) {}
256
257    _LIBCPP_INLINE_VISIBILITY
258    __base_pointer __self() {
259        return pointer_traits<__base_pointer>::pointer_to(*this);
260    }
261
262    _LIBCPP_INLINE_VISIBILITY
263    __node_pointer __as_node() {
264        return static_cast<__node_pointer>(__self());
265    }
266};
267
268template <class _Tp, class _VoidPtr>
269struct _LIBCPP_STANDALONE_DEBUG __list_node
270    : public __list_node_base<_Tp, _VoidPtr>
271{
272    _Tp __value_;
273
274    typedef __list_node_base<_Tp, _VoidPtr> __base;
275    typedef typename __base::__link_pointer __link_pointer;
276
277    _LIBCPP_INLINE_VISIBILITY
278    __link_pointer __as_link() {
279        return static_cast<__link_pointer>(__base::__self());
280    }
281};
282
283template <class _Tp, class _Alloc = allocator<_Tp> > class _LIBCPP_TEMPLATE_VIS list;
284template <class _Tp, class _Alloc> class __list_imp;
285template <class _Tp, class _VoidPtr> class _LIBCPP_TEMPLATE_VIS __list_const_iterator;
286
287template <class _Tp, class _VoidPtr>
288class _LIBCPP_TEMPLATE_VIS __list_iterator
289{
290    typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
291    typedef typename _NodeTraits::__link_pointer __link_pointer;
292
293    __link_pointer __ptr_;
294
295#if _LIBCPP_DEBUG_LEVEL == 2
296    _LIBCPP_INLINE_VISIBILITY
297    explicit __list_iterator(__link_pointer __p, const void* __c) _NOEXCEPT
298        : __ptr_(__p)
299    {
300        __get_db()->__insert_ic(this, __c);
301    }
302#else
303    _LIBCPP_INLINE_VISIBILITY
304    explicit __list_iterator(__link_pointer __p) _NOEXCEPT : __ptr_(__p) {}
305#endif
306
307
308
309    template<class, class> friend class list;
310    template<class, class> friend class __list_imp;
311    template<class, class> friend class __list_const_iterator;
312public:
313    typedef bidirectional_iterator_tag       iterator_category;
314    typedef _Tp                              value_type;
315    typedef value_type&                      reference;
316    typedef typename __rebind_pointer<_VoidPtr, value_type>::type pointer;
317    typedef typename pointer_traits<pointer>::difference_type difference_type;
318
319    _LIBCPP_INLINE_VISIBILITY
320    __list_iterator() _NOEXCEPT : __ptr_(nullptr)
321    {
322#if _LIBCPP_DEBUG_LEVEL == 2
323        __get_db()->__insert_i(this);
324#endif
325    }
326
327#if _LIBCPP_DEBUG_LEVEL == 2
328
329    _LIBCPP_INLINE_VISIBILITY
330    __list_iterator(const __list_iterator& __p)
331        : __ptr_(__p.__ptr_)
332    {
333        __get_db()->__iterator_copy(this, _VSTD::addressof(__p));
334    }
335
336    _LIBCPP_INLINE_VISIBILITY
337    ~__list_iterator()
338    {
339        __get_db()->__erase_i(this);
340    }
341
342    _LIBCPP_INLINE_VISIBILITY
343    __list_iterator& operator=(const __list_iterator& __p)
344    {
345        if (this != _VSTD::addressof(__p))
346        {
347            __get_db()->__iterator_copy(this, _VSTD::addressof(__p));
348            __ptr_ = __p.__ptr_;
349        }
350        return *this;
351    }
352
353#endif // _LIBCPP_DEBUG_LEVEL == 2
354
355    _LIBCPP_INLINE_VISIBILITY
356    reference operator*() const
357    {
358#if _LIBCPP_DEBUG_LEVEL == 2
359        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
360                       "Attempted to dereference a non-dereferenceable list::iterator");
361#endif
362        return __ptr_->__as_node()->__value_;
363    }
364    _LIBCPP_INLINE_VISIBILITY
365    pointer operator->() const
366    {
367#if _LIBCPP_DEBUG_LEVEL == 2
368        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
369                       "Attempted to dereference a non-dereferenceable list::iterator");
370#endif
371        return pointer_traits<pointer>::pointer_to(__ptr_->__as_node()->__value_);
372    }
373
374    _LIBCPP_INLINE_VISIBILITY
375    __list_iterator& operator++()
376    {
377#if _LIBCPP_DEBUG_LEVEL == 2
378        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
379                       "Attempted to increment a non-incrementable list::iterator");
380#endif
381        __ptr_ = __ptr_->__next_;
382        return *this;
383    }
384    _LIBCPP_INLINE_VISIBILITY
385    __list_iterator operator++(int) {__list_iterator __t(*this); ++(*this); return __t;}
386
387    _LIBCPP_INLINE_VISIBILITY
388    __list_iterator& operator--()
389    {
390#if _LIBCPP_DEBUG_LEVEL == 2
391        _LIBCPP_ASSERT(__get_const_db()->__decrementable(this),
392                       "Attempted to decrement a non-decrementable list::iterator");
393#endif
394        __ptr_ = __ptr_->__prev_;
395        return *this;
396    }
397    _LIBCPP_INLINE_VISIBILITY
398    __list_iterator operator--(int) {__list_iterator __t(*this); --(*this); return __t;}
399
400    friend _LIBCPP_INLINE_VISIBILITY
401    bool operator==(const __list_iterator& __x, const __list_iterator& __y)
402    {
403        return __x.__ptr_ == __y.__ptr_;
404    }
405    friend _LIBCPP_INLINE_VISIBILITY
406     bool operator!=(const __list_iterator& __x, const __list_iterator& __y)
407        {return !(__x == __y);}
408};
409
410template <class _Tp, class _VoidPtr>
411class _LIBCPP_TEMPLATE_VIS __list_const_iterator
412{
413    typedef __list_node_pointer_traits<_Tp, _VoidPtr> _NodeTraits;
414    typedef typename _NodeTraits::__link_pointer __link_pointer;
415
416    __link_pointer __ptr_;
417
418#if _LIBCPP_DEBUG_LEVEL == 2
419    _LIBCPP_INLINE_VISIBILITY
420    explicit __list_const_iterator(__link_pointer __p, const void* __c) _NOEXCEPT
421        : __ptr_(__p)
422    {
423        __get_db()->__insert_ic(this, __c);
424    }
425#else
426    _LIBCPP_INLINE_VISIBILITY
427    explicit __list_const_iterator(__link_pointer __p) _NOEXCEPT : __ptr_(__p) {}
428#endif
429
430    template<class, class> friend class list;
431    template<class, class> friend class __list_imp;
432public:
433    typedef bidirectional_iterator_tag       iterator_category;
434    typedef _Tp                              value_type;
435    typedef const value_type&                reference;
436    typedef typename __rebind_pointer<_VoidPtr, const value_type>::type pointer;
437    typedef typename pointer_traits<pointer>::difference_type difference_type;
438
439    _LIBCPP_INLINE_VISIBILITY
440    __list_const_iterator() _NOEXCEPT : __ptr_(nullptr)
441    {
442#if _LIBCPP_DEBUG_LEVEL == 2
443        __get_db()->__insert_i(this);
444#endif
445    }
446    _LIBCPP_INLINE_VISIBILITY
447    __list_const_iterator(const __list_iterator<_Tp, _VoidPtr>& __p) _NOEXCEPT
448        : __ptr_(__p.__ptr_)
449    {
450#if _LIBCPP_DEBUG_LEVEL == 2
451        __get_db()->__iterator_copy(this, _VSTD::addressof(__p));
452#endif
453    }
454
455#if _LIBCPP_DEBUG_LEVEL == 2
456
457    _LIBCPP_INLINE_VISIBILITY
458    __list_const_iterator(const __list_const_iterator& __p)
459        : __ptr_(__p.__ptr_)
460    {
461        __get_db()->__iterator_copy(this, _VSTD::addressof(__p));
462    }
463
464    _LIBCPP_INLINE_VISIBILITY
465    ~__list_const_iterator()
466    {
467        __get_db()->__erase_i(this);
468    }
469
470    _LIBCPP_INLINE_VISIBILITY
471    __list_const_iterator& operator=(const __list_const_iterator& __p)
472    {
473        if (this != _VSTD::addressof(__p))
474        {
475            __get_db()->__iterator_copy(this, _VSTD::addressof(__p));
476            __ptr_ = __p.__ptr_;
477        }
478        return *this;
479    }
480
481#endif // _LIBCPP_DEBUG_LEVEL == 2
482    _LIBCPP_INLINE_VISIBILITY
483    reference operator*() const
484    {
485#if _LIBCPP_DEBUG_LEVEL == 2
486        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
487                       "Attempted to dereference a non-dereferenceable list::const_iterator");
488#endif
489        return __ptr_->__as_node()->__value_;
490    }
491    _LIBCPP_INLINE_VISIBILITY
492    pointer operator->() const
493    {
494#if _LIBCPP_DEBUG_LEVEL == 2
495        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
496                       "Attempted to dereference a non-dereferenceable list::const_iterator");
497#endif
498        return pointer_traits<pointer>::pointer_to(__ptr_->__as_node()->__value_);
499    }
500
501    _LIBCPP_INLINE_VISIBILITY
502    __list_const_iterator& operator++()
503    {
504#if _LIBCPP_DEBUG_LEVEL == 2
505        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
506                       "Attempted to increment a non-incrementable list::const_iterator");
507#endif
508        __ptr_ = __ptr_->__next_;
509        return *this;
510    }
511    _LIBCPP_INLINE_VISIBILITY
512    __list_const_iterator operator++(int) {__list_const_iterator __t(*this); ++(*this); return __t;}
513
514    _LIBCPP_INLINE_VISIBILITY
515    __list_const_iterator& operator--()
516    {
517#if _LIBCPP_DEBUG_LEVEL == 2
518        _LIBCPP_ASSERT(__get_const_db()->__decrementable(this),
519                       "Attempted to decrement a non-decrementable list::const_iterator");
520#endif
521        __ptr_ = __ptr_->__prev_;
522        return *this;
523    }
524    _LIBCPP_INLINE_VISIBILITY
525    __list_const_iterator operator--(int) {__list_const_iterator __t(*this); --(*this); return __t;}
526
527    friend _LIBCPP_INLINE_VISIBILITY
528    bool operator==(const __list_const_iterator& __x, const __list_const_iterator& __y)
529    {
530        return __x.__ptr_ == __y.__ptr_;
531    }
532    friend _LIBCPP_INLINE_VISIBILITY
533    bool operator!=(const __list_const_iterator& __x, const __list_const_iterator& __y)
534        {return !(__x == __y);}
535};
536
537template <class _Tp, class _Alloc>
538class __list_imp
539{
540    __list_imp(const __list_imp&);
541    __list_imp& operator=(const __list_imp&);
542public:
543    typedef _Alloc                                                  allocator_type;
544    typedef allocator_traits<allocator_type>                        __alloc_traits;
545    typedef typename __alloc_traits::size_type                      size_type;
546protected:
547    typedef _Tp                                                     value_type;
548    typedef typename __alloc_traits::void_pointer                   __void_pointer;
549    typedef __list_iterator<value_type, __void_pointer>             iterator;
550    typedef __list_const_iterator<value_type, __void_pointer>       const_iterator;
551    typedef __list_node_base<value_type, __void_pointer>            __node_base;
552    typedef __list_node<value_type, __void_pointer>                 __node;
553    typedef typename __rebind_alloc_helper<__alloc_traits, __node>::type __node_allocator;
554    typedef allocator_traits<__node_allocator>                       __node_alloc_traits;
555    typedef typename __node_alloc_traits::pointer                    __node_pointer;
556    typedef typename __node_alloc_traits::pointer                    __node_const_pointer;
557    typedef __list_node_pointer_traits<value_type, __void_pointer> __node_pointer_traits;
558    typedef typename __node_pointer_traits::__link_pointer __link_pointer;
559    typedef __link_pointer __link_const_pointer;
560    typedef typename __alloc_traits::pointer                         pointer;
561    typedef typename __alloc_traits::const_pointer                   const_pointer;
562    typedef typename __alloc_traits::difference_type                 difference_type;
563
564    typedef typename __rebind_alloc_helper<__alloc_traits, __node_base>::type __node_base_allocator;
565    typedef typename allocator_traits<__node_base_allocator>::pointer __node_base_pointer;
566    static_assert((!is_same<allocator_type, __node_allocator>::value),
567                  "internal allocator type must differ from user-specified "
568                  "type; otherwise overload resolution breaks");
569
570    __node_base __end_;
571    __compressed_pair<size_type, __node_allocator> __size_alloc_;
572
573    _LIBCPP_INLINE_VISIBILITY
574    __link_pointer __end_as_link() const _NOEXCEPT {
575        return __node_pointer_traits::__unsafe_link_pointer_cast(
576                const_cast<__node_base&>(__end_).__self());
577    }
578
579    _LIBCPP_INLINE_VISIBILITY
580          size_type& __sz() _NOEXCEPT {return __size_alloc_.first();}
581    _LIBCPP_INLINE_VISIBILITY
582    const size_type& __sz() const _NOEXCEPT
583        {return __size_alloc_.first();}
584    _LIBCPP_INLINE_VISIBILITY
585          __node_allocator& __node_alloc() _NOEXCEPT
586          {return __size_alloc_.second();}
587    _LIBCPP_INLINE_VISIBILITY
588    const __node_allocator& __node_alloc() const _NOEXCEPT
589        {return __size_alloc_.second();}
590
591    _LIBCPP_INLINE_VISIBILITY
592    size_type __node_alloc_max_size() const _NOEXCEPT {
593        return __node_alloc_traits::max_size(__node_alloc());
594    }
595    _LIBCPP_INLINE_VISIBILITY
596    static void __unlink_nodes(__link_pointer __f, __link_pointer __l) _NOEXCEPT;
597
598    _LIBCPP_INLINE_VISIBILITY
599    __list_imp()
600        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value);
601    _LIBCPP_INLINE_VISIBILITY
602    __list_imp(const allocator_type& __a);
603    _LIBCPP_INLINE_VISIBILITY
604    __list_imp(const __node_allocator& __a);
605#ifndef _LIBCPP_CXX03_LANG
606    __list_imp(__node_allocator&& __a) _NOEXCEPT;
607#endif
608    ~__list_imp();
609    void clear() _NOEXCEPT;
610    _LIBCPP_INLINE_VISIBILITY
611    bool empty() const _NOEXCEPT {return __sz() == 0;}
612
613    _LIBCPP_INLINE_VISIBILITY
614    iterator begin() _NOEXCEPT
615    {
616#if _LIBCPP_DEBUG_LEVEL == 2
617        return iterator(__end_.__next_, this);
618#else
619        return iterator(__end_.__next_);
620#endif
621    }
622    _LIBCPP_INLINE_VISIBILITY
623    const_iterator begin() const  _NOEXCEPT
624    {
625#if _LIBCPP_DEBUG_LEVEL == 2
626        return const_iterator(__end_.__next_, this);
627#else
628        return const_iterator(__end_.__next_);
629#endif
630    }
631    _LIBCPP_INLINE_VISIBILITY
632    iterator end() _NOEXCEPT
633    {
634#if _LIBCPP_DEBUG_LEVEL == 2
635        return iterator(__end_as_link(), this);
636#else
637        return iterator(__end_as_link());
638#endif
639    }
640    _LIBCPP_INLINE_VISIBILITY
641    const_iterator end() const _NOEXCEPT
642    {
643#if _LIBCPP_DEBUG_LEVEL == 2
644        return const_iterator(__end_as_link(), this);
645#else
646        return const_iterator(__end_as_link());
647#endif
648    }
649
650    void swap(__list_imp& __c)
651#if _LIBCPP_STD_VER >= 14
652        _NOEXCEPT;
653#else
654        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
655                    __is_nothrow_swappable<allocator_type>::value);
656#endif
657
658    _LIBCPP_INLINE_VISIBILITY
659    void __copy_assign_alloc(const __list_imp& __c)
660        {__copy_assign_alloc(__c, integral_constant<bool,
661                      __node_alloc_traits::propagate_on_container_copy_assignment::value>());}
662
663    _LIBCPP_INLINE_VISIBILITY
664    void __move_assign_alloc(__list_imp& __c)
665        _NOEXCEPT_(
666            !__node_alloc_traits::propagate_on_container_move_assignment::value ||
667            is_nothrow_move_assignable<__node_allocator>::value)
668        {__move_assign_alloc(__c, integral_constant<bool,
669                      __node_alloc_traits::propagate_on_container_move_assignment::value>());}
670
671private:
672    _LIBCPP_INLINE_VISIBILITY
673    void __copy_assign_alloc(const __list_imp& __c, true_type)
674        {
675            if (__node_alloc() != __c.__node_alloc())
676                clear();
677            __node_alloc() = __c.__node_alloc();
678        }
679
680    _LIBCPP_INLINE_VISIBILITY
681    void __copy_assign_alloc(const __list_imp&, false_type)
682        {}
683
684    _LIBCPP_INLINE_VISIBILITY
685    void __move_assign_alloc(__list_imp& __c, true_type)
686        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value)
687        {
688            __node_alloc() = _VSTD::move(__c.__node_alloc());
689        }
690
691    _LIBCPP_INLINE_VISIBILITY
692    void __move_assign_alloc(__list_imp&, false_type)
693        _NOEXCEPT
694        {}
695
696    _LIBCPP_INLINE_VISIBILITY
697    void __invalidate_all_iterators() {
698#if _LIBCPP_DEBUG_LEVEL == 2
699      __get_db()->__invalidate_all(this);
700#endif
701    }
702};
703
704// Unlink nodes [__f, __l]
705template <class _Tp, class _Alloc>
706inline
707void
708__list_imp<_Tp, _Alloc>::__unlink_nodes(__link_pointer __f, __link_pointer __l)
709    _NOEXCEPT
710{
711    __f->__prev_->__next_ = __l->__next_;
712    __l->__next_->__prev_ = __f->__prev_;
713}
714
715template <class _Tp, class _Alloc>
716inline
717__list_imp<_Tp, _Alloc>::__list_imp()
718        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)
719    : __size_alloc_(0, __default_init_tag())
720{
721}
722
723template <class _Tp, class _Alloc>
724inline
725__list_imp<_Tp, _Alloc>::__list_imp(const allocator_type& __a)
726    : __size_alloc_(0, __node_allocator(__a))
727{
728}
729
730template <class _Tp, class _Alloc>
731inline __list_imp<_Tp, _Alloc>::__list_imp(const __node_allocator& __a)
732    : __size_alloc_(0, __a) {}
733
734#ifndef _LIBCPP_CXX03_LANG
735template <class _Tp, class _Alloc>
736inline __list_imp<_Tp, _Alloc>::__list_imp(__node_allocator&& __a) _NOEXCEPT
737    : __size_alloc_(0, _VSTD::move(__a)) {}
738#endif
739
740template <class _Tp, class _Alloc>
741__list_imp<_Tp, _Alloc>::~__list_imp() {
742  clear();
743#if _LIBCPP_DEBUG_LEVEL == 2
744    __get_db()->__erase_c(this);
745#endif
746}
747
748template <class _Tp, class _Alloc>
749void
750__list_imp<_Tp, _Alloc>::clear() _NOEXCEPT
751{
752    if (!empty())
753    {
754        __node_allocator& __na = __node_alloc();
755        __link_pointer __f = __end_.__next_;
756        __link_pointer __l = __end_as_link();
757        __unlink_nodes(__f, __l->__prev_);
758        __sz() = 0;
759        while (__f != __l)
760        {
761            __node_pointer __np = __f->__as_node();
762            __f = __f->__next_;
763            __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
764            __node_alloc_traits::deallocate(__na, __np, 1);
765        }
766        __invalidate_all_iterators();
767    }
768}
769
770template <class _Tp, class _Alloc>
771void
772__list_imp<_Tp, _Alloc>::swap(__list_imp& __c)
773#if _LIBCPP_STD_VER >= 14
774        _NOEXCEPT
775#else
776        _NOEXCEPT_(!__alloc_traits::propagate_on_container_swap::value ||
777                    __is_nothrow_swappable<allocator_type>::value)
778#endif
779{
780    _LIBCPP_ASSERT(__alloc_traits::propagate_on_container_swap::value ||
781                   this->__node_alloc() == __c.__node_alloc(),
782                   "list::swap: Either propagate_on_container_swap must be true"
783                   " or the allocators must compare equal");
784    using _VSTD::swap;
785    _VSTD::__swap_allocator(__node_alloc(), __c.__node_alloc());
786    swap(__sz(), __c.__sz());
787    swap(__end_, __c.__end_);
788    if (__sz() == 0)
789        __end_.__next_ = __end_.__prev_ = __end_as_link();
790    else
791        __end_.__prev_->__next_ = __end_.__next_->__prev_ = __end_as_link();
792    if (__c.__sz() == 0)
793        __c.__end_.__next_ = __c.__end_.__prev_ = __c.__end_as_link();
794    else
795        __c.__end_.__prev_->__next_ = __c.__end_.__next_->__prev_ = __c.__end_as_link();
796
797#if _LIBCPP_DEBUG_LEVEL == 2
798    __libcpp_db* __db = __get_db();
799    __c_node* __cn1 = __db->__find_c_and_lock(this);
800    __c_node* __cn2 = __db->__find_c(_VSTD::addressof(__c));
801    _VSTD::swap(__cn1->beg_, __cn2->beg_);
802    _VSTD::swap(__cn1->end_, __cn2->end_);
803    _VSTD::swap(__cn1->cap_, __cn2->cap_);
804    for (__i_node** __p = __cn1->end_; __p != __cn1->beg_;)
805    {
806        --__p;
807        const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);
808        if (__i->__ptr_ == __c.__end_as_link())
809        {
810            __cn2->__add(*__p);
811            if (--__cn1->end_ != __p)
812                _VSTD::memmove(__p, __p+1, (__cn1->end_ - __p)*sizeof(__i_node*));
813        }
814        else
815            (*__p)->__c_ = __cn1;
816    }
817    for (__i_node** __p = __cn2->end_; __p != __cn2->beg_;)
818    {
819        --__p;
820        const_iterator* __i = static_cast<const_iterator*>((*__p)->__i_);
821        if (__i->__ptr_ == __end_as_link())
822        {
823            __cn1->__add(*__p);
824            if (--__cn2->end_ != __p)
825                _VSTD::memmove(__p, __p+1, (__cn2->end_ - __p)*sizeof(__i_node*));
826        }
827        else
828            (*__p)->__c_ = __cn2;
829    }
830    __db->unlock();
831#endif
832}
833
834template <class _Tp, class _Alloc /*= allocator<_Tp>*/>
835class _LIBCPP_TEMPLATE_VIS list
836    : private __list_imp<_Tp, _Alloc>
837{
838    typedef __list_imp<_Tp, _Alloc> base;
839    typedef typename base::__node              __node;
840    typedef typename base::__node_allocator    __node_allocator;
841    typedef typename base::__node_pointer      __node_pointer;
842    typedef typename base::__node_alloc_traits __node_alloc_traits;
843    typedef typename base::__node_base         __node_base;
844    typedef typename base::__node_base_pointer __node_base_pointer;
845    typedef typename base::__link_pointer __link_pointer;
846
847public:
848    typedef _Tp                                            value_type;
849    typedef _Alloc                                         allocator_type;
850    static_assert((is_same<value_type, typename allocator_type::value_type>::value),
851                  "Invalid allocator::value_type");
852    typedef value_type&                                    reference;
853    typedef const value_type&                              const_reference;
854    typedef typename base::pointer                         pointer;
855    typedef typename base::const_pointer                   const_pointer;
856    typedef typename base::size_type                       size_type;
857    typedef typename base::difference_type                 difference_type;
858    typedef typename base::iterator                        iterator;
859    typedef typename base::const_iterator                  const_iterator;
860    typedef _VSTD::reverse_iterator<iterator>              reverse_iterator;
861    typedef _VSTD::reverse_iterator<const_iterator>        const_reverse_iterator;
862#if _LIBCPP_STD_VER > 17
863    typedef size_type                                      __remove_return_type;
864#else
865    typedef void                                           __remove_return_type;
866#endif
867
868    _LIBCPP_INLINE_VISIBILITY
869    list()
870        _NOEXCEPT_(is_nothrow_default_constructible<__node_allocator>::value)
871    {
872#if _LIBCPP_DEBUG_LEVEL == 2
873        __get_db()->__insert_c(this);
874#endif
875    }
876    _LIBCPP_INLINE_VISIBILITY
877    explicit list(const allocator_type& __a) : base(__a)
878    {
879#if _LIBCPP_DEBUG_LEVEL == 2
880        __get_db()->__insert_c(this);
881#endif
882    }
883    explicit list(size_type __n);
884#if _LIBCPP_STD_VER > 11
885    explicit list(size_type __n, const allocator_type& __a);
886#endif
887    list(size_type __n, const value_type& __x);
888    template <class = __enable_if_t<__is_allocator<_Alloc>::value> >
889    list(size_type __n, const value_type& __x, const allocator_type& __a) : base(__a)
890    {
891#if _LIBCPP_DEBUG_LEVEL == 2
892        __get_db()->__insert_c(this);
893#endif
894        for (; __n > 0; --__n)
895            push_back(__x);
896    }
897
898    template <class _InpIter>
899        list(_InpIter __f, _InpIter __l,
900             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type* = 0);
901    template <class _InpIter>
902        list(_InpIter __f, _InpIter __l, const allocator_type& __a,
903             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type* = 0);
904
905    list(const list& __c);
906    list(const list& __c, const __identity_t<allocator_type>& __a);
907    _LIBCPP_INLINE_VISIBILITY
908    list& operator=(const list& __c);
909#ifndef _LIBCPP_CXX03_LANG
910    list(initializer_list<value_type> __il);
911    list(initializer_list<value_type> __il, const allocator_type& __a);
912
913    _LIBCPP_INLINE_VISIBILITY
914    list(list&& __c)
915        _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value);
916    _LIBCPP_INLINE_VISIBILITY
917    list(list&& __c, const __identity_t<allocator_type>& __a);
918    _LIBCPP_INLINE_VISIBILITY
919    list& operator=(list&& __c)
920        _NOEXCEPT_(
921            __node_alloc_traits::propagate_on_container_move_assignment::value &&
922            is_nothrow_move_assignable<__node_allocator>::value);
923
924    _LIBCPP_INLINE_VISIBILITY
925    list& operator=(initializer_list<value_type> __il)
926        {assign(__il.begin(), __il.end()); return *this;}
927
928    _LIBCPP_INLINE_VISIBILITY
929    void assign(initializer_list<value_type> __il)
930        {assign(__il.begin(), __il.end());}
931#endif // _LIBCPP_CXX03_LANG
932
933    template <class _InpIter>
934        void assign(_InpIter __f, _InpIter __l,
935             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type* = 0);
936    void assign(size_type __n, const value_type& __x);
937
938    _LIBCPP_INLINE_VISIBILITY
939    allocator_type get_allocator() const _NOEXCEPT;
940
941    _LIBCPP_INLINE_VISIBILITY
942    size_type size() const _NOEXCEPT     {return base::__sz();}
943    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
944    bool empty() const _NOEXCEPT         {return base::empty();}
945    _LIBCPP_INLINE_VISIBILITY
946    size_type max_size() const _NOEXCEPT
947        {
948            return _VSTD::min<size_type>(
949                base::__node_alloc_max_size(),
950                numeric_limits<difference_type >::max());
951        }
952
953    _LIBCPP_INLINE_VISIBILITY
954          iterator begin() _NOEXCEPT        {return base::begin();}
955    _LIBCPP_INLINE_VISIBILITY
956    const_iterator begin()  const _NOEXCEPT {return base::begin();}
957    _LIBCPP_INLINE_VISIBILITY
958          iterator end() _NOEXCEPT          {return base::end();}
959    _LIBCPP_INLINE_VISIBILITY
960    const_iterator end()    const _NOEXCEPT {return base::end();}
961    _LIBCPP_INLINE_VISIBILITY
962    const_iterator cbegin() const _NOEXCEPT {return base::begin();}
963    _LIBCPP_INLINE_VISIBILITY
964    const_iterator cend()   const _NOEXCEPT {return base::end();}
965
966    _LIBCPP_INLINE_VISIBILITY
967          reverse_iterator rbegin() _NOEXCEPT
968            {return       reverse_iterator(end());}
969    _LIBCPP_INLINE_VISIBILITY
970    const_reverse_iterator rbegin()  const _NOEXCEPT
971        {return const_reverse_iterator(end());}
972    _LIBCPP_INLINE_VISIBILITY
973          reverse_iterator rend() _NOEXCEPT
974            {return       reverse_iterator(begin());}
975    _LIBCPP_INLINE_VISIBILITY
976    const_reverse_iterator rend()    const _NOEXCEPT
977        {return const_reverse_iterator(begin());}
978    _LIBCPP_INLINE_VISIBILITY
979    const_reverse_iterator crbegin() const _NOEXCEPT
980        {return const_reverse_iterator(end());}
981    _LIBCPP_INLINE_VISIBILITY
982    const_reverse_iterator crend()   const _NOEXCEPT
983        {return const_reverse_iterator(begin());}
984
985    _LIBCPP_INLINE_VISIBILITY
986    reference front()
987    {
988        _LIBCPP_ASSERT(!empty(), "list::front called on empty list");
989        return base::__end_.__next_->__as_node()->__value_;
990    }
991    _LIBCPP_INLINE_VISIBILITY
992    const_reference front() const
993    {
994        _LIBCPP_ASSERT(!empty(), "list::front called on empty list");
995        return base::__end_.__next_->__as_node()->__value_;
996    }
997    _LIBCPP_INLINE_VISIBILITY
998    reference back()
999    {
1000        _LIBCPP_ASSERT(!empty(), "list::back called on empty list");
1001        return base::__end_.__prev_->__as_node()->__value_;
1002    }
1003    _LIBCPP_INLINE_VISIBILITY
1004    const_reference back() const
1005    {
1006        _LIBCPP_ASSERT(!empty(), "list::back called on empty list");
1007        return base::__end_.__prev_->__as_node()->__value_;
1008    }
1009
1010#ifndef _LIBCPP_CXX03_LANG
1011    void push_front(value_type&& __x);
1012    void push_back(value_type&& __x);
1013
1014    template <class... _Args>
1015#if _LIBCPP_STD_VER > 14
1016       reference emplace_front(_Args&&... __args);
1017#else
1018       void      emplace_front(_Args&&... __args);
1019#endif
1020    template <class... _Args>
1021#if _LIBCPP_STD_VER > 14
1022        reference emplace_back(_Args&&... __args);
1023#else
1024       void       emplace_back(_Args&&... __args);
1025#endif
1026    template <class... _Args>
1027        iterator emplace(const_iterator __p, _Args&&... __args);
1028
1029    iterator insert(const_iterator __p, value_type&& __x);
1030
1031    _LIBCPP_INLINE_VISIBILITY
1032    iterator insert(const_iterator __p, initializer_list<value_type> __il)
1033        {return insert(__p, __il.begin(), __il.end());}
1034#endif // _LIBCPP_CXX03_LANG
1035
1036    void push_front(const value_type& __x);
1037    void push_back(const value_type& __x);
1038
1039#ifndef _LIBCPP_CXX03_LANG
1040    template <class _Arg>
1041    _LIBCPP_INLINE_VISIBILITY
1042    void __emplace_back(_Arg&& __arg) { emplace_back(_VSTD::forward<_Arg>(__arg)); }
1043#else
1044    _LIBCPP_INLINE_VISIBILITY
1045    void __emplace_back(value_type const& __arg) { push_back(__arg); }
1046#endif
1047
1048    iterator insert(const_iterator __p, const value_type& __x);
1049    iterator insert(const_iterator __p, size_type __n, const value_type& __x);
1050    template <class _InpIter>
1051        iterator insert(const_iterator __p, _InpIter __f, _InpIter __l,
1052             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type* = 0);
1053
1054    _LIBCPP_INLINE_VISIBILITY
1055    void swap(list& __c)
1056#if _LIBCPP_STD_VER >= 14
1057        _NOEXCEPT
1058#else
1059        _NOEXCEPT_(!__node_alloc_traits::propagate_on_container_swap::value ||
1060                   __is_nothrow_swappable<__node_allocator>::value)
1061#endif
1062        {base::swap(__c);}
1063    _LIBCPP_INLINE_VISIBILITY
1064    void clear() _NOEXCEPT {base::clear();}
1065
1066    void pop_front();
1067    void pop_back();
1068
1069    iterator erase(const_iterator __p);
1070    iterator erase(const_iterator __f, const_iterator __l);
1071
1072    void resize(size_type __n);
1073    void resize(size_type __n, const value_type& __x);
1074
1075    void splice(const_iterator __p, list& __c);
1076#ifndef _LIBCPP_CXX03_LANG
1077    _LIBCPP_INLINE_VISIBILITY
1078    void splice(const_iterator __p, list&& __c) {splice(__p, __c);}
1079    _LIBCPP_INLINE_VISIBILITY
1080    void splice(const_iterator __p, list&& __c, const_iterator __i)
1081        {splice(__p, __c, __i);}
1082    _LIBCPP_INLINE_VISIBILITY
1083    void splice(const_iterator __p, list&& __c, const_iterator __f, const_iterator __l)
1084        {splice(__p, __c, __f, __l);}
1085#endif
1086    void splice(const_iterator __p, list& __c, const_iterator __i);
1087    void splice(const_iterator __p, list& __c, const_iterator __f, const_iterator __l);
1088
1089    __remove_return_type remove(const value_type& __x);
1090    template <class _Pred> __remove_return_type remove_if(_Pred __pred);
1091    _LIBCPP_INLINE_VISIBILITY
1092    __remove_return_type unique() { return unique(__equal_to<value_type>()); }
1093    template <class _BinaryPred>
1094        __remove_return_type unique(_BinaryPred __binary_pred);
1095    _LIBCPP_INLINE_VISIBILITY
1096    void merge(list& __c);
1097#ifndef _LIBCPP_CXX03_LANG
1098    _LIBCPP_INLINE_VISIBILITY
1099    void merge(list&& __c) {merge(__c);}
1100
1101    template <class _Comp>
1102    _LIBCPP_INLINE_VISIBILITY
1103        void merge(list&& __c, _Comp __comp) {merge(__c, __comp);}
1104#endif
1105    template <class _Comp>
1106        void merge(list& __c, _Comp __comp);
1107
1108    _LIBCPP_INLINE_VISIBILITY
1109    void sort();
1110    template <class _Comp>
1111        _LIBCPP_INLINE_VISIBILITY
1112        void sort(_Comp __comp);
1113
1114    void reverse() _NOEXCEPT;
1115
1116    bool __invariants() const;
1117
1118    typedef __allocator_destructor<__node_allocator> __node_destructor;
1119    typedef unique_ptr<__node, __node_destructor> __hold_pointer;
1120
1121    _LIBCPP_INLINE_VISIBILITY
1122    __hold_pointer __allocate_node(__node_allocator& __na) {
1123      __node_pointer __p = __node_alloc_traits::allocate(__na, 1);
1124      __p->__prev_ = nullptr;
1125      return __hold_pointer(__p, __node_destructor(__na, 1));
1126    }
1127
1128#if _LIBCPP_DEBUG_LEVEL == 2
1129
1130    bool __dereferenceable(const const_iterator* __i) const;
1131    bool __decrementable(const const_iterator* __i) const;
1132    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
1133    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
1134
1135#endif // _LIBCPP_DEBUG_LEVEL == 2
1136
1137private:
1138    _LIBCPP_INLINE_VISIBILITY
1139    static void __link_nodes  (__link_pointer __p, __link_pointer __f, __link_pointer __l);
1140    _LIBCPP_INLINE_VISIBILITY
1141    void __link_nodes_at_front(__link_pointer __f, __link_pointer __l);
1142    _LIBCPP_INLINE_VISIBILITY
1143    void __link_nodes_at_back (__link_pointer __f, __link_pointer __l);
1144    iterator __iterator(size_type __n);
1145    template <class _Comp>
1146        static iterator __sort(iterator __f1, iterator __e2, size_type __n, _Comp& __comp);
1147
1148    void __move_assign(list& __c, true_type)
1149        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value);
1150    void __move_assign(list& __c, false_type);
1151};
1152
1153#if _LIBCPP_STD_VER >= 17
1154template<class _InputIterator,
1155         class _Alloc = allocator<__iter_value_type<_InputIterator>>,
1156         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
1157         class = enable_if_t<__is_allocator<_Alloc>::value>
1158         >
1159list(_InputIterator, _InputIterator)
1160  -> list<__iter_value_type<_InputIterator>, _Alloc>;
1161
1162template<class _InputIterator,
1163         class _Alloc,
1164         class = enable_if_t<__is_cpp17_input_iterator<_InputIterator>::value>,
1165         class = enable_if_t<__is_allocator<_Alloc>::value>
1166         >
1167list(_InputIterator, _InputIterator, _Alloc)
1168  -> list<__iter_value_type<_InputIterator>, _Alloc>;
1169#endif
1170
1171// Link in nodes [__f, __l] just prior to __p
1172template <class _Tp, class _Alloc>
1173inline
1174void
1175list<_Tp, _Alloc>::__link_nodes(__link_pointer __p, __link_pointer __f, __link_pointer __l)
1176{
1177    __p->__prev_->__next_ = __f;
1178    __f->__prev_ = __p->__prev_;
1179    __p->__prev_ = __l;
1180    __l->__next_ = __p;
1181}
1182
1183// Link in nodes [__f, __l] at the front of the list
1184template <class _Tp, class _Alloc>
1185inline
1186void
1187list<_Tp, _Alloc>::__link_nodes_at_front(__link_pointer __f, __link_pointer __l)
1188{
1189    __f->__prev_ = base::__end_as_link();
1190    __l->__next_ = base::__end_.__next_;
1191    __l->__next_->__prev_ = __l;
1192    base::__end_.__next_ = __f;
1193}
1194
1195// Link in nodes [__f, __l] at the back of the list
1196template <class _Tp, class _Alloc>
1197inline
1198void
1199list<_Tp, _Alloc>::__link_nodes_at_back(__link_pointer __f, __link_pointer __l)
1200{
1201    __l->__next_ = base::__end_as_link();
1202    __f->__prev_ = base::__end_.__prev_;
1203    __f->__prev_->__next_ = __f;
1204    base::__end_.__prev_ = __l;
1205}
1206
1207
1208template <class _Tp, class _Alloc>
1209inline
1210typename list<_Tp, _Alloc>::iterator
1211list<_Tp, _Alloc>::__iterator(size_type __n)
1212{
1213    return __n <= base::__sz() / 2 ? _VSTD::next(begin(), __n)
1214                                   : _VSTD::prev(end(), base::__sz() - __n);
1215}
1216
1217template <class _Tp, class _Alloc>
1218list<_Tp, _Alloc>::list(size_type __n)
1219{
1220#if _LIBCPP_DEBUG_LEVEL == 2
1221    __get_db()->__insert_c(this);
1222#endif
1223    for (; __n > 0; --__n)
1224#ifndef _LIBCPP_CXX03_LANG
1225        emplace_back();
1226#else
1227        push_back(value_type());
1228#endif
1229}
1230
1231#if _LIBCPP_STD_VER > 11
1232template <class _Tp, class _Alloc>
1233list<_Tp, _Alloc>::list(size_type __n, const allocator_type& __a) : base(__a)
1234{
1235#if _LIBCPP_DEBUG_LEVEL == 2
1236    __get_db()->__insert_c(this);
1237#endif
1238    for (; __n > 0; --__n)
1239        emplace_back();
1240}
1241#endif
1242
1243template <class _Tp, class _Alloc>
1244list<_Tp, _Alloc>::list(size_type __n, const value_type& __x)
1245{
1246#if _LIBCPP_DEBUG_LEVEL == 2
1247    __get_db()->__insert_c(this);
1248#endif
1249    for (; __n > 0; --__n)
1250        push_back(__x);
1251}
1252
1253template <class _Tp, class _Alloc>
1254template <class _InpIter>
1255list<_Tp, _Alloc>::list(_InpIter __f, _InpIter __l,
1256                        typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type*)
1257{
1258#if _LIBCPP_DEBUG_LEVEL == 2
1259    __get_db()->__insert_c(this);
1260#endif
1261    for (; __f != __l; ++__f)
1262        __emplace_back(*__f);
1263}
1264
1265template <class _Tp, class _Alloc>
1266template <class _InpIter>
1267list<_Tp, _Alloc>::list(_InpIter __f, _InpIter __l, const allocator_type& __a,
1268                        typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type*)
1269    : base(__a)
1270{
1271#if _LIBCPP_DEBUG_LEVEL == 2
1272    __get_db()->__insert_c(this);
1273#endif
1274    for (; __f != __l; ++__f)
1275        __emplace_back(*__f);
1276}
1277
1278template <class _Tp, class _Alloc>
1279list<_Tp, _Alloc>::list(const list& __c)
1280    : base(__node_alloc_traits::select_on_container_copy_construction(
1281          __c.__node_alloc())) {
1282#if _LIBCPP_DEBUG_LEVEL == 2
1283    __get_db()->__insert_c(this);
1284#endif
1285    for (const_iterator __i = __c.begin(), __e = __c.end(); __i != __e; ++__i)
1286        push_back(*__i);
1287}
1288
1289template <class _Tp, class _Alloc>
1290list<_Tp, _Alloc>::list(const list& __c, const __identity_t<allocator_type>& __a)
1291    : base(__a)
1292{
1293#if _LIBCPP_DEBUG_LEVEL == 2
1294    __get_db()->__insert_c(this);
1295#endif
1296    for (const_iterator __i = __c.begin(), __e = __c.end(); __i != __e; ++__i)
1297        push_back(*__i);
1298}
1299
1300#ifndef _LIBCPP_CXX03_LANG
1301
1302template <class _Tp, class _Alloc>
1303list<_Tp, _Alloc>::list(initializer_list<value_type> __il, const allocator_type& __a)
1304    : base(__a)
1305{
1306#if _LIBCPP_DEBUG_LEVEL == 2
1307    __get_db()->__insert_c(this);
1308#endif
1309    for (typename initializer_list<value_type>::const_iterator __i = __il.begin(),
1310            __e = __il.end(); __i != __e; ++__i)
1311        push_back(*__i);
1312}
1313
1314template <class _Tp, class _Alloc>
1315list<_Tp, _Alloc>::list(initializer_list<value_type> __il)
1316{
1317#if _LIBCPP_DEBUG_LEVEL == 2
1318    __get_db()->__insert_c(this);
1319#endif
1320    for (typename initializer_list<value_type>::const_iterator __i = __il.begin(),
1321            __e = __il.end(); __i != __e; ++__i)
1322        push_back(*__i);
1323}
1324
1325template <class _Tp, class _Alloc>
1326inline list<_Tp, _Alloc>::list(list&& __c)
1327    _NOEXCEPT_(is_nothrow_move_constructible<__node_allocator>::value)
1328    : base(_VSTD::move(__c.__node_alloc())) {
1329#if _LIBCPP_DEBUG_LEVEL == 2
1330    __get_db()->__insert_c(this);
1331#endif
1332    splice(end(), __c);
1333}
1334
1335template <class _Tp, class _Alloc>
1336inline
1337list<_Tp, _Alloc>::list(list&& __c, const __identity_t<allocator_type>& __a)
1338    : base(__a)
1339{
1340#if _LIBCPP_DEBUG_LEVEL == 2
1341    __get_db()->__insert_c(this);
1342#endif
1343    if (__a == __c.get_allocator())
1344        splice(end(), __c);
1345    else
1346    {
1347        typedef move_iterator<iterator> _Ip;
1348        assign(_Ip(__c.begin()), _Ip(__c.end()));
1349    }
1350}
1351
1352template <class _Tp, class _Alloc>
1353inline
1354list<_Tp, _Alloc>&
1355list<_Tp, _Alloc>::operator=(list&& __c)
1356        _NOEXCEPT_(
1357            __node_alloc_traits::propagate_on_container_move_assignment::value &&
1358            is_nothrow_move_assignable<__node_allocator>::value)
1359{
1360    __move_assign(__c, integral_constant<bool,
1361          __node_alloc_traits::propagate_on_container_move_assignment::value>());
1362    return *this;
1363}
1364
1365template <class _Tp, class _Alloc>
1366void
1367list<_Tp, _Alloc>::__move_assign(list& __c, false_type)
1368{
1369    if (base::__node_alloc() != __c.__node_alloc())
1370    {
1371        typedef move_iterator<iterator> _Ip;
1372        assign(_Ip(__c.begin()), _Ip(__c.end()));
1373    }
1374    else
1375        __move_assign(__c, true_type());
1376}
1377
1378template <class _Tp, class _Alloc>
1379void
1380list<_Tp, _Alloc>::__move_assign(list& __c, true_type)
1381        _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value)
1382{
1383    clear();
1384    base::__move_assign_alloc(__c);
1385    splice(end(), __c);
1386}
1387
1388#endif // _LIBCPP_CXX03_LANG
1389
1390template <class _Tp, class _Alloc>
1391inline
1392list<_Tp, _Alloc>&
1393list<_Tp, _Alloc>::operator=(const list& __c)
1394{
1395    if (this != _VSTD::addressof(__c))
1396    {
1397        base::__copy_assign_alloc(__c);
1398        assign(__c.begin(), __c.end());
1399    }
1400    return *this;
1401}
1402
1403template <class _Tp, class _Alloc>
1404template <class _InpIter>
1405void
1406list<_Tp, _Alloc>::assign(_InpIter __f, _InpIter __l,
1407                          typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type*)
1408{
1409    iterator __i = begin();
1410    iterator __e = end();
1411    for (; __f != __l && __i != __e; ++__f, (void) ++__i)
1412        *__i = *__f;
1413    if (__i == __e)
1414        insert(__e, __f, __l);
1415    else
1416        erase(__i, __e);
1417#if _LIBCPP_DEBUG_LEVEL == 2
1418      __get_db()->__invalidate_all(this);
1419#endif
1420}
1421
1422template <class _Tp, class _Alloc>
1423void
1424list<_Tp, _Alloc>::assign(size_type __n, const value_type& __x)
1425{
1426    iterator __i = begin();
1427    iterator __e = end();
1428    for (; __n > 0 && __i != __e; --__n, (void) ++__i)
1429        *__i = __x;
1430    if (__i == __e)
1431        insert(__e, __n, __x);
1432    else
1433        erase(__i, __e);
1434#if _LIBCPP_DEBUG_LEVEL == 2
1435      __get_db()->__invalidate_all(this);
1436#endif
1437}
1438
1439template <class _Tp, class _Alloc>
1440inline
1441_Alloc
1442list<_Tp, _Alloc>::get_allocator() const _NOEXCEPT
1443{
1444    return allocator_type(base::__node_alloc());
1445}
1446
1447template <class _Tp, class _Alloc>
1448typename list<_Tp, _Alloc>::iterator
1449list<_Tp, _Alloc>::insert(const_iterator __p, const value_type& __x)
1450{
1451#if _LIBCPP_DEBUG_LEVEL == 2
1452    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
1453        "list::insert(iterator, x) called with an iterator not"
1454        " referring to this list");
1455#endif
1456    __node_allocator& __na = base::__node_alloc();
1457    __hold_pointer __hold = __allocate_node(__na);
1458    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
1459    __link_nodes(__p.__ptr_, __hold->__as_link(), __hold->__as_link());
1460    ++base::__sz();
1461#if _LIBCPP_DEBUG_LEVEL == 2
1462    return iterator(__hold.release()->__as_link(), this);
1463#else
1464    return iterator(__hold.release()->__as_link());
1465#endif
1466}
1467
1468template <class _Tp, class _Alloc>
1469typename list<_Tp, _Alloc>::iterator
1470list<_Tp, _Alloc>::insert(const_iterator __p, size_type __n, const value_type& __x)
1471{
1472#if _LIBCPP_DEBUG_LEVEL == 2
1473    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
1474        "list::insert(iterator, n, x) called with an iterator not"
1475        " referring to this list");
1476    iterator __r(__p.__ptr_, this);
1477#else
1478    iterator __r(__p.__ptr_);
1479#endif
1480    if (__n > 0)
1481    {
1482        size_type __ds = 0;
1483        __node_allocator& __na = base::__node_alloc();
1484        __hold_pointer __hold = __allocate_node(__na);
1485        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
1486        ++__ds;
1487#if _LIBCPP_DEBUG_LEVEL == 2
1488        __r = iterator(__hold->__as_link(), this);
1489#else
1490        __r = iterator(__hold->__as_link());
1491#endif
1492        __hold.release();
1493        iterator __e = __r;
1494#ifndef _LIBCPP_NO_EXCEPTIONS
1495        try
1496        {
1497#endif // _LIBCPP_NO_EXCEPTIONS
1498            for (--__n; __n != 0; --__n, (void) ++__e, ++__ds)
1499            {
1500                __hold.reset(__node_alloc_traits::allocate(__na, 1));
1501                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
1502                __e.__ptr_->__next_ = __hold->__as_link();
1503                __hold->__prev_ = __e.__ptr_;
1504                __hold.release();
1505            }
1506#ifndef _LIBCPP_NO_EXCEPTIONS
1507        }
1508        catch (...)
1509        {
1510            while (true)
1511            {
1512                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
1513                __link_pointer __prev = __e.__ptr_->__prev_;
1514                __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 1);
1515                if (__prev == 0)
1516                    break;
1517#if _LIBCPP_DEBUG_LEVEL == 2
1518                __e = iterator(__prev, this);
1519#else
1520                __e = iterator(__prev);
1521#endif
1522            }
1523            throw;
1524        }
1525#endif // _LIBCPP_NO_EXCEPTIONS
1526        __link_nodes(__p.__ptr_, __r.__ptr_, __e.__ptr_);
1527        base::__sz() += __ds;
1528    }
1529    return __r;
1530}
1531
1532template <class _Tp, class _Alloc>
1533template <class _InpIter>
1534typename list<_Tp, _Alloc>::iterator
1535list<_Tp, _Alloc>::insert(const_iterator __p, _InpIter __f, _InpIter __l,
1536             typename enable_if<__is_cpp17_input_iterator<_InpIter>::value>::type*)
1537{
1538#if _LIBCPP_DEBUG_LEVEL == 2
1539    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
1540        "list::insert(iterator, range) called with an iterator not"
1541        " referring to this list");
1542    iterator __r(__p.__ptr_, this);
1543#else
1544    iterator __r(__p.__ptr_);
1545#endif
1546    if (__f != __l)
1547    {
1548        size_type __ds = 0;
1549        __node_allocator& __na = base::__node_alloc();
1550        __hold_pointer __hold = __allocate_node(__na);
1551        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), *__f);
1552        ++__ds;
1553#if _LIBCPP_DEBUG_LEVEL == 2
1554        __r = iterator(__hold.get()->__as_link(), this);
1555#else
1556        __r = iterator(__hold.get()->__as_link());
1557#endif
1558        __hold.release();
1559        iterator __e = __r;
1560#ifndef _LIBCPP_NO_EXCEPTIONS
1561        try
1562        {
1563#endif // _LIBCPP_NO_EXCEPTIONS
1564            for (++__f; __f != __l; ++__f, (void) ++__e, ++__ds)
1565            {
1566                __hold.reset(__node_alloc_traits::allocate(__na, 1));
1567                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), *__f);
1568                __e.__ptr_->__next_ = __hold.get()->__as_link();
1569                __hold->__prev_ = __e.__ptr_;
1570                __hold.release();
1571            }
1572#ifndef _LIBCPP_NO_EXCEPTIONS
1573        }
1574        catch (...)
1575        {
1576            while (true)
1577            {
1578                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
1579                __link_pointer __prev = __e.__ptr_->__prev_;
1580                __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 1);
1581                if (__prev == 0)
1582                    break;
1583#if _LIBCPP_DEBUG_LEVEL == 2
1584                __e = iterator(__prev, this);
1585#else
1586                __e = iterator(__prev);
1587#endif
1588            }
1589            throw;
1590        }
1591#endif // _LIBCPP_NO_EXCEPTIONS
1592        __link_nodes(__p.__ptr_, __r.__ptr_, __e.__ptr_);
1593        base::__sz() += __ds;
1594    }
1595    return __r;
1596}
1597
1598template <class _Tp, class _Alloc>
1599void
1600list<_Tp, _Alloc>::push_front(const value_type& __x)
1601{
1602    __node_allocator& __na = base::__node_alloc();
1603    __hold_pointer __hold = __allocate_node(__na);
1604    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
1605    __link_pointer __nl = __hold->__as_link();
1606    __link_nodes_at_front(__nl, __nl);
1607    ++base::__sz();
1608    __hold.release();
1609}
1610
1611template <class _Tp, class _Alloc>
1612void
1613list<_Tp, _Alloc>::push_back(const value_type& __x)
1614{
1615    __node_allocator& __na = base::__node_alloc();
1616    __hold_pointer __hold = __allocate_node(__na);
1617    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
1618    __link_nodes_at_back(__hold.get()->__as_link(), __hold.get()->__as_link());
1619    ++base::__sz();
1620    __hold.release();
1621}
1622
1623#ifndef _LIBCPP_CXX03_LANG
1624
1625template <class _Tp, class _Alloc>
1626void
1627list<_Tp, _Alloc>::push_front(value_type&& __x)
1628{
1629    __node_allocator& __na = base::__node_alloc();
1630    __hold_pointer __hold = __allocate_node(__na);
1631    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::move(__x));
1632    __link_nodes_at_front(__hold.get()->__as_link(), __hold.get()->__as_link());
1633    ++base::__sz();
1634    __hold.release();
1635}
1636
1637template <class _Tp, class _Alloc>
1638void
1639list<_Tp, _Alloc>::push_back(value_type&& __x)
1640{
1641    __node_allocator& __na = base::__node_alloc();
1642    __hold_pointer __hold = __allocate_node(__na);
1643    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::move(__x));
1644    __link_nodes_at_back(__hold.get()->__as_link(), __hold.get()->__as_link());
1645    ++base::__sz();
1646    __hold.release();
1647}
1648
1649template <class _Tp, class _Alloc>
1650template <class... _Args>
1651#if _LIBCPP_STD_VER > 14
1652typename list<_Tp, _Alloc>::reference
1653#else
1654void
1655#endif
1656list<_Tp, _Alloc>::emplace_front(_Args&&... __args)
1657{
1658    __node_allocator& __na = base::__node_alloc();
1659    __hold_pointer __hold = __allocate_node(__na);
1660    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::forward<_Args>(__args)...);
1661    __link_nodes_at_front(__hold.get()->__as_link(), __hold.get()->__as_link());
1662    ++base::__sz();
1663#if _LIBCPP_STD_VER > 14
1664    return __hold.release()->__value_;
1665#else
1666    __hold.release();
1667#endif
1668}
1669
1670template <class _Tp, class _Alloc>
1671template <class... _Args>
1672#if _LIBCPP_STD_VER > 14
1673typename list<_Tp, _Alloc>::reference
1674#else
1675void
1676#endif
1677list<_Tp, _Alloc>::emplace_back(_Args&&... __args)
1678{
1679    __node_allocator& __na = base::__node_alloc();
1680    __hold_pointer __hold = __allocate_node(__na);
1681    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::forward<_Args>(__args)...);
1682    __link_pointer __nl = __hold->__as_link();
1683    __link_nodes_at_back(__nl, __nl);
1684    ++base::__sz();
1685#if _LIBCPP_STD_VER > 14
1686    return __hold.release()->__value_;
1687#else
1688    __hold.release();
1689#endif
1690}
1691
1692template <class _Tp, class _Alloc>
1693template <class... _Args>
1694typename list<_Tp, _Alloc>::iterator
1695list<_Tp, _Alloc>::emplace(const_iterator __p, _Args&&... __args)
1696{
1697#if _LIBCPP_DEBUG_LEVEL == 2
1698    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
1699        "list::emplace(iterator, args...) called with an iterator not"
1700        " referring to this list");
1701#endif
1702    __node_allocator& __na = base::__node_alloc();
1703    __hold_pointer __hold = __allocate_node(__na);
1704    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::forward<_Args>(__args)...);
1705    __link_pointer __nl = __hold.get()->__as_link();
1706    __link_nodes(__p.__ptr_, __nl, __nl);
1707    ++base::__sz();
1708    __hold.release();
1709#if _LIBCPP_DEBUG_LEVEL == 2
1710    return iterator(__nl, this);
1711#else
1712    return iterator(__nl);
1713#endif
1714}
1715
1716template <class _Tp, class _Alloc>
1717typename list<_Tp, _Alloc>::iterator
1718list<_Tp, _Alloc>::insert(const_iterator __p, value_type&& __x)
1719{
1720#if _LIBCPP_DEBUG_LEVEL == 2
1721    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
1722        "list::insert(iterator, x) called with an iterator not"
1723        " referring to this list");
1724#endif
1725    __node_allocator& __na = base::__node_alloc();
1726    __hold_pointer __hold = __allocate_node(__na);
1727    __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), _VSTD::move(__x));
1728    __link_pointer __nl = __hold->__as_link();
1729    __link_nodes(__p.__ptr_, __nl, __nl);
1730    ++base::__sz();
1731    __hold.release();
1732#if _LIBCPP_DEBUG_LEVEL == 2
1733    return iterator(__nl, this);
1734#else
1735    return iterator(__nl);
1736#endif
1737}
1738
1739#endif // _LIBCPP_CXX03_LANG
1740
1741template <class _Tp, class _Alloc>
1742void
1743list<_Tp, _Alloc>::pop_front()
1744{
1745    _LIBCPP_ASSERT(!empty(), "list::pop_front() called with empty list");
1746    __node_allocator& __na = base::__node_alloc();
1747    __link_pointer __n = base::__end_.__next_;
1748    base::__unlink_nodes(__n, __n);
1749    --base::__sz();
1750#if _LIBCPP_DEBUG_LEVEL == 2
1751    __c_node* __c = __get_db()->__find_c_and_lock(this);
1752    for (__i_node** __p = __c->end_; __p != __c->beg_; )
1753    {
1754        --__p;
1755        iterator* __i = static_cast<iterator*>((*__p)->__i_);
1756        if (__i->__ptr_ == __n)
1757        {
1758            (*__p)->__c_ = nullptr;
1759            if (--__c->end_ != __p)
1760                _VSTD::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
1761        }
1762    }
1763    __get_db()->unlock();
1764#endif
1765    __node_pointer __np = __n->__as_node();
1766    __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
1767    __node_alloc_traits::deallocate(__na, __np, 1);
1768}
1769
1770template <class _Tp, class _Alloc>
1771void
1772list<_Tp, _Alloc>::pop_back()
1773{
1774    _LIBCPP_ASSERT(!empty(), "list::pop_back() called on an empty list");
1775    __node_allocator& __na = base::__node_alloc();
1776    __link_pointer __n = base::__end_.__prev_;
1777    base::__unlink_nodes(__n, __n);
1778    --base::__sz();
1779#if _LIBCPP_DEBUG_LEVEL == 2
1780    __c_node* __c = __get_db()->__find_c_and_lock(this);
1781    for (__i_node** __p = __c->end_; __p != __c->beg_; )
1782    {
1783        --__p;
1784        iterator* __i = static_cast<iterator*>((*__p)->__i_);
1785        if (__i->__ptr_ == __n)
1786        {
1787            (*__p)->__c_ = nullptr;
1788            if (--__c->end_ != __p)
1789                _VSTD::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
1790        }
1791    }
1792    __get_db()->unlock();
1793#endif
1794    __node_pointer __np = __n->__as_node();
1795    __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
1796    __node_alloc_traits::deallocate(__na, __np, 1);
1797}
1798
1799template <class _Tp, class _Alloc>
1800typename list<_Tp, _Alloc>::iterator
1801list<_Tp, _Alloc>::erase(const_iterator __p)
1802{
1803#if _LIBCPP_DEBUG_LEVEL == 2
1804    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
1805        "list::erase(iterator) called with an iterator not"
1806        " referring to this list");
1807#endif
1808    _LIBCPP_ASSERT(__p != end(),
1809        "list::erase(iterator) called with a non-dereferenceable iterator");
1810    __node_allocator& __na = base::__node_alloc();
1811    __link_pointer __n = __p.__ptr_;
1812    __link_pointer __r = __n->__next_;
1813    base::__unlink_nodes(__n, __n);
1814    --base::__sz();
1815#if _LIBCPP_DEBUG_LEVEL == 2
1816    __c_node* __c = __get_db()->__find_c_and_lock(this);
1817    for (__i_node** __ip = __c->end_; __ip != __c->beg_; )
1818    {
1819        --__ip;
1820        iterator* __i = static_cast<iterator*>((*__ip)->__i_);
1821        if (__i->__ptr_ == __n)
1822        {
1823            (*__ip)->__c_ = nullptr;
1824            if (--__c->end_ != __ip)
1825                _VSTD::memmove(__ip, __ip+1, (__c->end_ - __ip)*sizeof(__i_node*));
1826        }
1827    }
1828    __get_db()->unlock();
1829#endif
1830    __node_pointer __np = __n->__as_node();
1831    __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
1832    __node_alloc_traits::deallocate(__na, __np, 1);
1833#if _LIBCPP_DEBUG_LEVEL == 2
1834    return iterator(__r, this);
1835#else
1836    return iterator(__r);
1837#endif
1838}
1839
1840template <class _Tp, class _Alloc>
1841typename list<_Tp, _Alloc>::iterator
1842list<_Tp, _Alloc>::erase(const_iterator __f, const_iterator __l)
1843{
1844#if _LIBCPP_DEBUG_LEVEL == 2
1845    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__f)) == this,
1846        "list::erase(iterator, iterator) called with an iterator not"
1847        " referring to this list");
1848   _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__l)) == this,
1849        "list::erase(iterator, iterator) called with an iterator not"
1850        " referring to this list");
1851#endif
1852    if (__f != __l)
1853    {
1854        __node_allocator& __na = base::__node_alloc();
1855        base::__unlink_nodes(__f.__ptr_, __l.__ptr_->__prev_);
1856        while (__f != __l)
1857        {
1858            __link_pointer __n = __f.__ptr_;
1859            ++__f;
1860            --base::__sz();
1861#if _LIBCPP_DEBUG_LEVEL == 2
1862            __c_node* __c = __get_db()->__find_c_and_lock(this);
1863            for (__i_node** __p = __c->end_; __p != __c->beg_; )
1864            {
1865                --__p;
1866                iterator* __i = static_cast<iterator*>((*__p)->__i_);
1867                if (__i->__ptr_ == __n)
1868                {
1869                    (*__p)->__c_ = nullptr;
1870                    if (--__c->end_ != __p)
1871                        _VSTD::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
1872                }
1873            }
1874            __get_db()->unlock();
1875#endif
1876            __node_pointer __np = __n->__as_node();
1877            __node_alloc_traits::destroy(__na, _VSTD::addressof(__np->__value_));
1878            __node_alloc_traits::deallocate(__na, __np, 1);
1879        }
1880    }
1881#if _LIBCPP_DEBUG_LEVEL == 2
1882    return iterator(__l.__ptr_, this);
1883#else
1884    return iterator(__l.__ptr_);
1885#endif
1886}
1887
1888template <class _Tp, class _Alloc>
1889void
1890list<_Tp, _Alloc>::resize(size_type __n)
1891{
1892    if (__n < base::__sz())
1893        erase(__iterator(__n), end());
1894    else if (__n > base::__sz())
1895    {
1896        __n -= base::__sz();
1897        size_type __ds = 0;
1898        __node_allocator& __na = base::__node_alloc();
1899        __hold_pointer __hold = __allocate_node(__na);
1900        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_));
1901        ++__ds;
1902#if _LIBCPP_DEBUG_LEVEL == 2
1903        iterator __r = iterator(__hold.release()->__as_link(), this);
1904#else
1905        iterator __r = iterator(__hold.release()->__as_link());
1906#endif
1907        iterator __e = __r;
1908#ifndef _LIBCPP_NO_EXCEPTIONS
1909        try
1910        {
1911#endif // _LIBCPP_NO_EXCEPTIONS
1912            for (--__n; __n != 0; --__n, (void) ++__e, ++__ds)
1913            {
1914                __hold.reset(__node_alloc_traits::allocate(__na, 1));
1915                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_));
1916                __e.__ptr_->__next_ = __hold.get()->__as_link();
1917                __hold->__prev_ = __e.__ptr_;
1918                __hold.release();
1919            }
1920#ifndef _LIBCPP_NO_EXCEPTIONS
1921        }
1922        catch (...)
1923        {
1924            while (true)
1925            {
1926                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
1927                __link_pointer __prev = __e.__ptr_->__prev_;
1928                __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 1);
1929                if (__prev == 0)
1930                    break;
1931#if _LIBCPP_DEBUG_LEVEL == 2
1932                __e = iterator(__prev, this);
1933#else
1934                __e = iterator(__prev);
1935#endif
1936            }
1937            throw;
1938        }
1939#endif // _LIBCPP_NO_EXCEPTIONS
1940        __link_nodes_at_back(__r.__ptr_, __e.__ptr_);
1941        base::__sz() += __ds;
1942    }
1943}
1944
1945template <class _Tp, class _Alloc>
1946void
1947list<_Tp, _Alloc>::resize(size_type __n, const value_type& __x)
1948{
1949    if (__n < base::__sz())
1950        erase(__iterator(__n), end());
1951    else if (__n > base::__sz())
1952    {
1953        __n -= base::__sz();
1954        size_type __ds = 0;
1955        __node_allocator& __na = base::__node_alloc();
1956        __hold_pointer __hold = __allocate_node(__na);
1957        __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
1958        ++__ds;
1959        __link_pointer __nl = __hold.release()->__as_link();
1960#if _LIBCPP_DEBUG_LEVEL == 2
1961        iterator __r = iterator(__nl, this);
1962#else
1963        iterator __r = iterator(__nl);
1964#endif
1965        iterator __e = __r;
1966#ifndef _LIBCPP_NO_EXCEPTIONS
1967        try
1968        {
1969#endif // _LIBCPP_NO_EXCEPTIONS
1970            for (--__n; __n != 0; --__n, (void) ++__e, ++__ds)
1971            {
1972                __hold.reset(__node_alloc_traits::allocate(__na, 1));
1973                __node_alloc_traits::construct(__na, _VSTD::addressof(__hold->__value_), __x);
1974                __e.__ptr_->__next_ = __hold.get()->__as_link();
1975                __hold->__prev_ = __e.__ptr_;
1976                __hold.release();
1977            }
1978#ifndef _LIBCPP_NO_EXCEPTIONS
1979        }
1980        catch (...)
1981        {
1982            while (true)
1983            {
1984                __node_alloc_traits::destroy(__na, _VSTD::addressof(*__e));
1985                __link_pointer __prev = __e.__ptr_->__prev_;
1986                __node_alloc_traits::deallocate(__na, __e.__ptr_->__as_node(), 1);
1987                if (__prev == 0)
1988                    break;
1989#if _LIBCPP_DEBUG_LEVEL == 2
1990                __e = iterator(__prev, this);
1991#else
1992                __e = iterator(__prev);
1993#endif
1994            }
1995            throw;
1996        }
1997#endif // _LIBCPP_NO_EXCEPTIONS
1998        __link_nodes(base::__end_as_link(), __r.__ptr_, __e.__ptr_);
1999        base::__sz() += __ds;
2000    }
2001}
2002
2003template <class _Tp, class _Alloc>
2004void
2005list<_Tp, _Alloc>::splice(const_iterator __p, list& __c)
2006{
2007    _LIBCPP_ASSERT(this != _VSTD::addressof(__c),
2008                   "list::splice(iterator, list) called with this == &list");
2009#if _LIBCPP_DEBUG_LEVEL == 2
2010    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
2011        "list::splice(iterator, list) called with an iterator not"
2012        " referring to this list");
2013#endif
2014    if (!__c.empty())
2015    {
2016        __link_pointer __f = __c.__end_.__next_;
2017        __link_pointer __l = __c.__end_.__prev_;
2018        base::__unlink_nodes(__f, __l);
2019        __link_nodes(__p.__ptr_, __f, __l);
2020        base::__sz() += __c.__sz();
2021        __c.__sz() = 0;
2022#if _LIBCPP_DEBUG_LEVEL == 2
2023        if (_VSTD::addressof(__c) != this) {
2024            __libcpp_db* __db = __get_db();
2025            __c_node* __cn1 = __db->__find_c_and_lock(this);
2026            __c_node* __cn2 = __db->__find_c(_VSTD::addressof(__c));
2027            for (__i_node** __ip = __cn2->end_; __ip != __cn2->beg_;)
2028            {
2029                --__ip;
2030                iterator* __i = static_cast<iterator*>((*__ip)->__i_);
2031                if (__i->__ptr_ != __c.__end_as_link())
2032                {
2033                    __cn1->__add(*__ip);
2034                    (*__ip)->__c_ = __cn1;
2035                    if (--__cn2->end_ != __ip)
2036                        _VSTD::memmove(__ip, __ip+1, (__cn2->end_ - __ip)*sizeof(__i_node*));
2037                }
2038            }
2039            __db->unlock();
2040        }
2041#endif
2042    }
2043}
2044
2045template <class _Tp, class _Alloc>
2046void
2047list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __i)
2048{
2049#if _LIBCPP_DEBUG_LEVEL == 2
2050    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
2051        "list::splice(iterator, list, iterator) called with the first iterator"
2052        " not referring to this list");
2053    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__i)) == _VSTD::addressof(__c),
2054        "list::splice(iterator, list, iterator) called with the second iterator"
2055        " not referring to the list argument");
2056    _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(_VSTD::addressof(__i)),
2057        "list::splice(iterator, list, iterator) called with the second iterator"
2058        " not dereferenceable");
2059#endif
2060    if (__p.__ptr_ != __i.__ptr_ && __p.__ptr_ != __i.__ptr_->__next_)
2061    {
2062        __link_pointer __f = __i.__ptr_;
2063        base::__unlink_nodes(__f, __f);
2064        __link_nodes(__p.__ptr_, __f, __f);
2065        --__c.__sz();
2066        ++base::__sz();
2067#if _LIBCPP_DEBUG_LEVEL == 2
2068        if (_VSTD::addressof(__c) != this) {
2069            __libcpp_db* __db = __get_db();
2070            __c_node* __cn1 = __db->__find_c_and_lock(this);
2071            __c_node* __cn2 = __db->__find_c(_VSTD::addressof(__c));
2072            for (__i_node** __ip = __cn2->end_; __ip != __cn2->beg_;)
2073            {
2074                --__ip;
2075                iterator* __j = static_cast<iterator*>((*__ip)->__i_);
2076                if (__j->__ptr_ == __f)
2077                {
2078                    __cn1->__add(*__ip);
2079                    (*__ip)->__c_ = __cn1;
2080                    if (--__cn2->end_ != __ip)
2081                        _VSTD::memmove(__ip, __ip+1, (__cn2->end_ - __ip)*sizeof(__i_node*));
2082                }
2083            }
2084            __db->unlock();
2085        }
2086#endif
2087    }
2088}
2089
2090template <class _Tp, class _Alloc>
2091void
2092list<_Tp, _Alloc>::splice(const_iterator __p, list& __c, const_iterator __f, const_iterator __l)
2093{
2094#if _LIBCPP_DEBUG_LEVEL == 2
2095    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
2096        "list::splice(iterator, list, iterator, iterator) called with first iterator not"
2097        " referring to this list");
2098    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__f)) == _VSTD::addressof(__c),
2099        "list::splice(iterator, list, iterator, iterator) called with second iterator not"
2100        " referring to the list argument");
2101    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__l)) == _VSTD::addressof(__c),
2102        "list::splice(iterator, list, iterator, iterator) called with third iterator not"
2103        " referring to the list argument");
2104    if (this == _VSTD::addressof(__c))
2105    {
2106        for (const_iterator __i = __f; __i != __l; ++__i)
2107            _LIBCPP_ASSERT(__i != __p,
2108                           "list::splice(iterator, list, iterator, iterator)"
2109                           " called with the first iterator within the range"
2110                           " of the second and third iterators");
2111    }
2112#endif
2113    if (__f != __l)
2114    {
2115        __link_pointer __first = __f.__ptr_;
2116        --__l;
2117        __link_pointer __last = __l.__ptr_;
2118        if (this != _VSTD::addressof(__c))
2119        {
2120            size_type __s = _VSTD::distance(__f, __l) + 1;
2121            __c.__sz() -= __s;
2122            base::__sz() += __s;
2123        }
2124        base::__unlink_nodes(__first, __last);
2125        __link_nodes(__p.__ptr_, __first, __last);
2126#if _LIBCPP_DEBUG_LEVEL == 2
2127        if (_VSTD::addressof(__c) != this) {
2128            __libcpp_db* __db = __get_db();
2129            __c_node* __cn1 = __db->__find_c_and_lock(this);
2130            __c_node* __cn2 = __db->__find_c(_VSTD::addressof(__c));
2131            for (__i_node** __ip = __cn2->end_; __ip != __cn2->beg_;)
2132            {
2133                --__ip;
2134                iterator* __j = static_cast<iterator*>((*__ip)->__i_);
2135                for (__link_pointer __k = __f.__ptr_;
2136                                              __k != __l.__ptr_; __k = __k->__next_)
2137                {
2138                    if (__j->__ptr_ == __k)
2139                    {
2140                        __cn1->__add(*__ip);
2141                        (*__ip)->__c_ = __cn1;
2142                        if (--__cn2->end_ != __ip)
2143                            _VSTD::memmove(__ip, __ip+1, (__cn2->end_ - __ip)*sizeof(__i_node*));
2144                    }
2145                }
2146            }
2147            __db->unlock();
2148        }
2149#endif
2150    }
2151}
2152
2153template <class _Tp, class _Alloc>
2154typename list<_Tp, _Alloc>::__remove_return_type
2155list<_Tp, _Alloc>::remove(const value_type& __x)
2156{
2157    list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
2158    for (const_iterator __i = begin(), __e = end(); __i != __e;)
2159    {
2160        if (*__i == __x)
2161        {
2162            const_iterator __j = _VSTD::next(__i);
2163            for (; __j != __e && *__j == __x; ++__j)
2164                ;
2165            __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
2166            __i = __j;
2167            if (__i != __e)
2168                ++__i;
2169        }
2170        else
2171            ++__i;
2172    }
2173
2174    return (__remove_return_type) __deleted_nodes.size();
2175}
2176
2177template <class _Tp, class _Alloc>
2178template <class _Pred>
2179typename list<_Tp, _Alloc>::__remove_return_type
2180list<_Tp, _Alloc>::remove_if(_Pred __pred)
2181{
2182    list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
2183    for (iterator __i = begin(), __e = end(); __i != __e;)
2184    {
2185        if (__pred(*__i))
2186        {
2187            iterator __j = _VSTD::next(__i);
2188            for (; __j != __e && __pred(*__j); ++__j)
2189                ;
2190            __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
2191            __i = __j;
2192            if (__i != __e)
2193                ++__i;
2194        }
2195        else
2196            ++__i;
2197    }
2198
2199    return (__remove_return_type) __deleted_nodes.size();
2200}
2201
2202template <class _Tp, class _Alloc>
2203template <class _BinaryPred>
2204typename list<_Tp, _Alloc>::__remove_return_type
2205list<_Tp, _Alloc>::unique(_BinaryPred __binary_pred)
2206{
2207    list<_Tp, _Alloc> __deleted_nodes(get_allocator()); // collect the nodes we're removing
2208    for (iterator __i = begin(), __e = end(); __i != __e;)
2209    {
2210        iterator __j = _VSTD::next(__i);
2211        for (; __j != __e && __binary_pred(*__i, *__j); ++__j)
2212            ;
2213        if (++__i != __j) {
2214            __deleted_nodes.splice(__deleted_nodes.end(), *this, __i, __j);
2215            __i = __j;
2216            }
2217    }
2218
2219    return (__remove_return_type) __deleted_nodes.size();
2220}
2221
2222template <class _Tp, class _Alloc>
2223inline
2224void
2225list<_Tp, _Alloc>::merge(list& __c)
2226{
2227    merge(__c, __less<value_type>());
2228}
2229
2230template <class _Tp, class _Alloc>
2231template <class _Comp>
2232void
2233list<_Tp, _Alloc>::merge(list& __c, _Comp __comp)
2234{
2235    if (this != _VSTD::addressof(__c))
2236    {
2237        iterator __f1 = begin();
2238        iterator __e1 = end();
2239        iterator __f2 = __c.begin();
2240        iterator __e2 = __c.end();
2241        while (__f1 != __e1 && __f2 != __e2)
2242        {
2243            if (__comp(*__f2, *__f1))
2244            {
2245                size_type __ds = 1;
2246                iterator __m2 = _VSTD::next(__f2);
2247                for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2, (void) ++__ds)
2248                    ;
2249                base::__sz() += __ds;
2250                __c.__sz() -= __ds;
2251                __link_pointer __f = __f2.__ptr_;
2252                __link_pointer __l = __m2.__ptr_->__prev_;
2253                __f2 = __m2;
2254                base::__unlink_nodes(__f, __l);
2255                __m2 = _VSTD::next(__f1);
2256                __link_nodes(__f1.__ptr_, __f, __l);
2257                __f1 = __m2;
2258            }
2259            else
2260                ++__f1;
2261        }
2262        splice(__e1, __c);
2263#if _LIBCPP_DEBUG_LEVEL == 2
2264        __libcpp_db* __db = __get_db();
2265        __c_node* __cn1 = __db->__find_c_and_lock(this);
2266        __c_node* __cn2 = __db->__find_c(_VSTD::addressof(__c));
2267        for (__i_node** __p = __cn2->end_; __p != __cn2->beg_;)
2268        {
2269            --__p;
2270            iterator* __i = static_cast<iterator*>((*__p)->__i_);
2271            if (__i->__ptr_ != __c.__end_as_link())
2272            {
2273                __cn1->__add(*__p);
2274                (*__p)->__c_ = __cn1;
2275                if (--__cn2->end_ != __p)
2276                    _VSTD::memmove(__p, __p+1, (__cn2->end_ - __p)*sizeof(__i_node*));
2277            }
2278        }
2279        __db->unlock();
2280#endif
2281    }
2282}
2283
2284template <class _Tp, class _Alloc>
2285inline
2286void
2287list<_Tp, _Alloc>::sort()
2288{
2289    sort(__less<value_type>());
2290}
2291
2292template <class _Tp, class _Alloc>
2293template <class _Comp>
2294inline
2295void
2296list<_Tp, _Alloc>::sort(_Comp __comp)
2297{
2298    __sort(begin(), end(), base::__sz(), __comp);
2299}
2300
2301template <class _Tp, class _Alloc>
2302template <class _Comp>
2303typename list<_Tp, _Alloc>::iterator
2304list<_Tp, _Alloc>::__sort(iterator __f1, iterator __e2, size_type __n, _Comp& __comp)
2305{
2306    switch (__n)
2307    {
2308    case 0:
2309    case 1:
2310        return __f1;
2311    case 2:
2312        if (__comp(*--__e2, *__f1))
2313        {
2314            __link_pointer __f = __e2.__ptr_;
2315            base::__unlink_nodes(__f, __f);
2316            __link_nodes(__f1.__ptr_, __f, __f);
2317            return __e2;
2318        }
2319        return __f1;
2320    }
2321    size_type __n2 = __n / 2;
2322    iterator __e1 = _VSTD::next(__f1, __n2);
2323    iterator  __r = __f1 = __sort(__f1, __e1, __n2, __comp);
2324    iterator __f2 = __e1 = __sort(__e1, __e2, __n - __n2, __comp);
2325    if (__comp(*__f2, *__f1))
2326    {
2327        iterator __m2 = _VSTD::next(__f2);
2328        for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2)
2329            ;
2330        __link_pointer __f = __f2.__ptr_;
2331        __link_pointer __l = __m2.__ptr_->__prev_;
2332        __r = __f2;
2333        __e1 = __f2 = __m2;
2334        base::__unlink_nodes(__f, __l);
2335        __m2 = _VSTD::next(__f1);
2336        __link_nodes(__f1.__ptr_, __f, __l);
2337        __f1 = __m2;
2338    }
2339    else
2340        ++__f1;
2341    while (__f1 != __e1 && __f2 != __e2)
2342    {
2343        if (__comp(*__f2, *__f1))
2344        {
2345            iterator __m2 = _VSTD::next(__f2);
2346            for (; __m2 != __e2 && __comp(*__m2, *__f1); ++__m2)
2347                ;
2348            __link_pointer __f = __f2.__ptr_;
2349            __link_pointer __l = __m2.__ptr_->__prev_;
2350            if (__e1 == __f2)
2351                __e1 = __m2;
2352            __f2 = __m2;
2353            base::__unlink_nodes(__f, __l);
2354            __m2 = _VSTD::next(__f1);
2355            __link_nodes(__f1.__ptr_, __f, __l);
2356            __f1 = __m2;
2357        }
2358        else
2359            ++__f1;
2360    }
2361    return __r;
2362}
2363
2364template <class _Tp, class _Alloc>
2365void
2366list<_Tp, _Alloc>::reverse() _NOEXCEPT
2367{
2368    if (base::__sz() > 1)
2369    {
2370        iterator __e = end();
2371        for (iterator __i = begin(); __i.__ptr_ != __e.__ptr_;)
2372        {
2373            _VSTD::swap(__i.__ptr_->__prev_, __i.__ptr_->__next_);
2374            __i.__ptr_ = __i.__ptr_->__prev_;
2375        }
2376        _VSTD::swap(__e.__ptr_->__prev_, __e.__ptr_->__next_);
2377    }
2378}
2379
2380template <class _Tp, class _Alloc>
2381bool
2382list<_Tp, _Alloc>::__invariants() const
2383{
2384    return size() == _VSTD::distance(begin(), end());
2385}
2386
2387#if _LIBCPP_DEBUG_LEVEL == 2
2388
2389template <class _Tp, class _Alloc>
2390bool
2391list<_Tp, _Alloc>::__dereferenceable(const const_iterator* __i) const
2392{
2393    return __i->__ptr_ != this->__end_as_link();
2394}
2395
2396template <class _Tp, class _Alloc>
2397bool
2398list<_Tp, _Alloc>::__decrementable(const const_iterator* __i) const
2399{
2400    return !empty() &&  __i->__ptr_ != base::__end_.__next_;
2401}
2402
2403template <class _Tp, class _Alloc>
2404bool
2405list<_Tp, _Alloc>::__addable(const const_iterator*, ptrdiff_t) const
2406{
2407    return false;
2408}
2409
2410template <class _Tp, class _Alloc>
2411bool
2412list<_Tp, _Alloc>::__subscriptable(const const_iterator*, ptrdiff_t) const
2413{
2414    return false;
2415}
2416
2417#endif // _LIBCPP_DEBUG_LEVEL == 2
2418
2419template <class _Tp, class _Alloc>
2420inline _LIBCPP_INLINE_VISIBILITY
2421bool
2422operator==(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
2423{
2424    return __x.size() == __y.size() && _VSTD::equal(__x.begin(), __x.end(), __y.begin());
2425}
2426
2427template <class _Tp, class _Alloc>
2428inline _LIBCPP_INLINE_VISIBILITY
2429bool
2430operator< (const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
2431{
2432    return _VSTD::lexicographical_compare(__x.begin(), __x.end(), __y.begin(), __y.end());
2433}
2434
2435template <class _Tp, class _Alloc>
2436inline _LIBCPP_INLINE_VISIBILITY
2437bool
2438operator!=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
2439{
2440    return !(__x == __y);
2441}
2442
2443template <class _Tp, class _Alloc>
2444inline _LIBCPP_INLINE_VISIBILITY
2445bool
2446operator> (const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
2447{
2448    return __y < __x;
2449}
2450
2451template <class _Tp, class _Alloc>
2452inline _LIBCPP_INLINE_VISIBILITY
2453bool
2454operator>=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
2455{
2456    return !(__x < __y);
2457}
2458
2459template <class _Tp, class _Alloc>
2460inline _LIBCPP_INLINE_VISIBILITY
2461bool
2462operator<=(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
2463{
2464    return !(__y < __x);
2465}
2466
2467template <class _Tp, class _Alloc>
2468inline _LIBCPP_INLINE_VISIBILITY
2469void
2470swap(list<_Tp, _Alloc>& __x, list<_Tp, _Alloc>& __y)
2471    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
2472{
2473    __x.swap(__y);
2474}
2475
2476#if _LIBCPP_STD_VER > 17
2477template <class _Tp, class _Allocator, class _Predicate>
2478inline _LIBCPP_INLINE_VISIBILITY typename list<_Tp, _Allocator>::size_type
2479erase_if(list<_Tp, _Allocator>& __c, _Predicate __pred) {
2480  return __c.remove_if(__pred);
2481}
2482
2483template <class _Tp, class _Allocator, class _Up>
2484inline _LIBCPP_INLINE_VISIBILITY typename list<_Tp, _Allocator>::size_type
2485erase(list<_Tp, _Allocator>& __c, const _Up& __v) {
2486  return _VSTD::erase_if(__c, [&](auto& __elem) { return __elem == __v; });
2487}
2488#endif
2489
2490_LIBCPP_END_NAMESPACE_STD
2491
2492_LIBCPP_POP_MACROS
2493
2494#endif // _LIBCPP_LIST
2495