xref: /freebsd/contrib/llvm-project/libcxx/include/__hash_table (revision 7ef62cebc2f965b0f640263e179276928885e33d)
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___HASH_TABLE
11#define _LIBCPP___HASH_TABLE
12
13#include <__algorithm/max.h>
14#include <__algorithm/min.h>
15#include <__assert>
16#include <__bit/countl.h>
17#include <__config>
18#include <__debug>
19#include <__functional/hash.h>
20#include <__iterator/iterator_traits.h>
21#include <__memory/addressof.h>
22#include <__memory/allocator_traits.h>
23#include <__memory/compressed_pair.h>
24#include <__memory/pointer_traits.h>
25#include <__memory/swap_allocator.h>
26#include <__memory/unique_ptr.h>
27#include <__type_traits/can_extract_key.h>
28#include <__utility/forward.h>
29#include <__utility/move.h>
30#include <__utility/pair.h>
31#include <__utility/swap.h>
32#include <cmath>
33#include <cstring>
34#include <initializer_list>
35#include <type_traits>
36
37#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
38#  pragma GCC system_header
39#endif
40
41_LIBCPP_PUSH_MACROS
42#include <__undef_macros>
43
44
45_LIBCPP_BEGIN_NAMESPACE_STD
46
47template <class _Key, class _Tp>
48struct __hash_value_type;
49
50template <class _Tp>
51struct __is_hash_value_type_imp : false_type {};
52
53template <class _Key, class _Value>
54struct __is_hash_value_type_imp<__hash_value_type<_Key, _Value> > : true_type {};
55
56template <class ..._Args>
57struct __is_hash_value_type : false_type {};
58
59template <class _One>
60struct __is_hash_value_type<_One> : __is_hash_value_type_imp<__remove_cvref_t<_One> > {};
61
62_LIBCPP_FUNC_VIS
63size_t __next_prime(size_t __n);
64
65template <class _NodePtr>
66struct __hash_node_base
67{
68    typedef typename pointer_traits<_NodePtr>::element_type __node_type;
69    typedef __hash_node_base __first_node;
70    typedef __rebind_pointer_t<_NodePtr, __first_node> __node_base_pointer;
71    typedef _NodePtr __node_pointer;
72
73#if defined(_LIBCPP_ABI_FIX_UNORDERED_NODE_POINTER_UB)
74  typedef __node_base_pointer __next_pointer;
75#else
76    typedef __conditional_t<is_pointer<__node_pointer>::value, __node_base_pointer, __node_pointer> __next_pointer;
77#endif
78
79    __next_pointer    __next_;
80
81    _LIBCPP_INLINE_VISIBILITY
82    __next_pointer __ptr() _NOEXCEPT {
83        return static_cast<__next_pointer>(
84            pointer_traits<__node_base_pointer>::pointer_to(*this));
85    }
86
87    _LIBCPP_INLINE_VISIBILITY
88    __node_pointer __upcast() _NOEXCEPT {
89        return static_cast<__node_pointer>(
90            pointer_traits<__node_base_pointer>::pointer_to(*this));
91    }
92
93    _LIBCPP_INLINE_VISIBILITY
94    size_t __hash() const _NOEXCEPT {
95        return static_cast<__node_type const&>(*this).__hash_;
96    }
97
98    _LIBCPP_INLINE_VISIBILITY __hash_node_base() _NOEXCEPT : __next_(nullptr) {}
99};
100
101template <class _Tp, class _VoidPtr>
102struct _LIBCPP_STANDALONE_DEBUG __hash_node
103    : public __hash_node_base
104             <
105                 __rebind_pointer_t<_VoidPtr, __hash_node<_Tp, _VoidPtr> >
106             >
107{
108    typedef _Tp __node_value_type;
109
110    size_t            __hash_;
111    __node_value_type __value_;
112};
113
114inline _LIBCPP_INLINE_VISIBILITY
115bool
116__is_hash_power2(size_t __bc)
117{
118    return __bc > 2 && !(__bc & (__bc - 1));
119}
120
121inline _LIBCPP_INLINE_VISIBILITY
122size_t
123__constrain_hash(size_t __h, size_t __bc)
124{
125    return !(__bc & (__bc - 1)) ? __h & (__bc - 1) :
126        (__h < __bc ? __h : __h % __bc);
127}
128
129inline _LIBCPP_INLINE_VISIBILITY
130size_t
131__next_hash_pow2(size_t __n)
132{
133    return __n < 2 ? __n : (size_t(1) << (numeric_limits<size_t>::digits - __libcpp_clz(__n-1)));
134}
135
136
137template <class _Tp, class _Hash, class _Equal, class _Alloc> class __hash_table;
138
139template <class _NodePtr>      class _LIBCPP_TEMPLATE_VIS __hash_iterator;
140template <class _ConstNodePtr> class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
141template <class _NodePtr>      class _LIBCPP_TEMPLATE_VIS __hash_local_iterator;
142template <class _ConstNodePtr> class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
143template <class _HashIterator> class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
144template <class _HashIterator> class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
145
146template <class _Tp>
147struct __hash_key_value_types {
148  static_assert(!is_reference<_Tp>::value && !is_const<_Tp>::value, "");
149  typedef _Tp key_type;
150  typedef _Tp __node_value_type;
151  typedef _Tp __container_value_type;
152  static const bool __is_map = false;
153
154  _LIBCPP_INLINE_VISIBILITY
155  static key_type const& __get_key(_Tp const& __v) {
156    return __v;
157  }
158  _LIBCPP_INLINE_VISIBILITY
159  static __container_value_type const& __get_value(__node_value_type const& __v) {
160    return __v;
161  }
162  _LIBCPP_INLINE_VISIBILITY
163  static __container_value_type* __get_ptr(__node_value_type& __n) {
164    return _VSTD::addressof(__n);
165  }
166  _LIBCPP_INLINE_VISIBILITY
167  static __container_value_type&& __move(__node_value_type& __v) {
168    return _VSTD::move(__v);
169  }
170};
171
172template <class _Key, class _Tp>
173struct __hash_key_value_types<__hash_value_type<_Key, _Tp> > {
174  typedef _Key                                         key_type;
175  typedef _Tp                                          mapped_type;
176  typedef __hash_value_type<_Key, _Tp>                 __node_value_type;
177  typedef pair<const _Key, _Tp>                        __container_value_type;
178  typedef __container_value_type                       __map_value_type;
179  static const bool __is_map = true;
180
181  _LIBCPP_INLINE_VISIBILITY
182  static key_type const& __get_key(__container_value_type const& __v) {
183    return __v.first;
184  }
185
186  template <class _Up>
187  _LIBCPP_INLINE_VISIBILITY
188  static __enable_if_t<__is_same_uncvref<_Up, __node_value_type>::value, __container_value_type const&>
189  __get_value(_Up& __t) {
190    return __t.__get_value();
191  }
192
193  template <class _Up>
194  _LIBCPP_INLINE_VISIBILITY
195  static __enable_if_t<__is_same_uncvref<_Up, __container_value_type>::value, __container_value_type const&>
196  __get_value(_Up& __t) {
197    return __t;
198  }
199
200  _LIBCPP_INLINE_VISIBILITY
201  static __container_value_type* __get_ptr(__node_value_type& __n) {
202    return _VSTD::addressof(__n.__get_value());
203  }
204  _LIBCPP_INLINE_VISIBILITY
205  static pair<key_type&&, mapped_type&&> __move(__node_value_type& __v) {
206    return __v.__move();
207  }
208};
209
210template <class _Tp, class _AllocPtr, class _KVTypes = __hash_key_value_types<_Tp>,
211          bool = _KVTypes::__is_map>
212struct __hash_map_pointer_types {};
213
214template <class _Tp, class _AllocPtr, class _KVTypes>
215struct __hash_map_pointer_types<_Tp, _AllocPtr, _KVTypes, true> {
216  typedef typename _KVTypes::__map_value_type   _Mv;
217  typedef __rebind_pointer_t<_AllocPtr, _Mv>
218                                                       __map_value_type_pointer;
219  typedef __rebind_pointer_t<_AllocPtr, const _Mv>
220                                                 __const_map_value_type_pointer;
221};
222
223template <class _NodePtr, class _NodeT = typename pointer_traits<_NodePtr>::element_type>
224struct __hash_node_types;
225
226template <class _NodePtr, class _Tp, class _VoidPtr>
227struct __hash_node_types<_NodePtr, __hash_node<_Tp, _VoidPtr> >
228    : public __hash_key_value_types<_Tp>, __hash_map_pointer_types<_Tp, _VoidPtr>
229
230{
231  typedef __hash_key_value_types<_Tp>           __base;
232
233public:
234  typedef ptrdiff_t difference_type;
235  typedef size_t size_type;
236
237  typedef __rebind_pointer_t<_NodePtr, void>       __void_pointer;
238
239  typedef typename pointer_traits<_NodePtr>::element_type       __node_type;
240  typedef _NodePtr                                              __node_pointer;
241
242  typedef __hash_node_base<__node_pointer>                      __node_base_type;
243  typedef __rebind_pointer_t<_NodePtr, __node_base_type>
244                                                             __node_base_pointer;
245
246  typedef typename __node_base_type::__next_pointer          __next_pointer;
247
248  typedef _Tp                                                 __node_value_type;
249  typedef __rebind_pointer_t<_VoidPtr, __node_value_type>
250                                                      __node_value_type_pointer;
251  typedef __rebind_pointer_t<_VoidPtr, const __node_value_type>
252                                                __const_node_value_type_pointer;
253
254private:
255    static_assert(!is_const<__node_type>::value,
256                "_NodePtr should never be a pointer to const");
257    static_assert((is_same<typename pointer_traits<_VoidPtr>::element_type, void>::value),
258                  "_VoidPtr does not point to unqualified void type");
259    static_assert((is_same<__rebind_pointer_t<_VoidPtr, __node_type>,
260                          _NodePtr>::value), "_VoidPtr does not rebind to _NodePtr.");
261};
262
263template <class _HashIterator>
264struct __hash_node_types_from_iterator;
265template <class _NodePtr>
266struct __hash_node_types_from_iterator<__hash_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
267template <class _NodePtr>
268struct __hash_node_types_from_iterator<__hash_const_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
269template <class _NodePtr>
270struct __hash_node_types_from_iterator<__hash_local_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
271template <class _NodePtr>
272struct __hash_node_types_from_iterator<__hash_const_local_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
273
274
275template <class _NodeValueTp, class _VoidPtr>
276struct __make_hash_node_types {
277  typedef __hash_node<_NodeValueTp, _VoidPtr> _NodeTp;
278  typedef __rebind_pointer_t<_VoidPtr, _NodeTp> _NodePtr;
279  typedef __hash_node_types<_NodePtr> type;
280};
281
282template <class _NodePtr>
283class _LIBCPP_TEMPLATE_VIS __hash_iterator
284{
285    typedef __hash_node_types<_NodePtr> _NodeTypes;
286    typedef _NodePtr                            __node_pointer;
287    typedef typename _NodeTypes::__next_pointer __next_pointer;
288
289    __next_pointer            __node_;
290
291public:
292    typedef forward_iterator_tag                           iterator_category;
293    typedef typename _NodeTypes::__node_value_type         value_type;
294    typedef typename _NodeTypes::difference_type           difference_type;
295    typedef value_type&                                    reference;
296    typedef typename _NodeTypes::__node_value_type_pointer pointer;
297
298    _LIBCPP_INLINE_VISIBILITY __hash_iterator() _NOEXCEPT : __node_(nullptr) {
299        _VSTD::__debug_db_insert_i(this);
300    }
301
302#ifdef _LIBCPP_ENABLE_DEBUG_MODE
303    _LIBCPP_INLINE_VISIBILITY
304    __hash_iterator(const __hash_iterator& __i)
305        : __node_(__i.__node_)
306    {
307        __get_db()->__iterator_copy(this, _VSTD::addressof(__i));
308    }
309
310    _LIBCPP_INLINE_VISIBILITY
311    ~__hash_iterator()
312    {
313        __get_db()->__erase_i(this);
314    }
315
316    _LIBCPP_INLINE_VISIBILITY
317    __hash_iterator& operator=(const __hash_iterator& __i)
318    {
319        if (this != _VSTD::addressof(__i))
320        {
321            __get_db()->__iterator_copy(this, _VSTD::addressof(__i));
322            __node_ = __i.__node_;
323        }
324        return *this;
325    }
326#endif // _LIBCPP_ENABLE_DEBUG_MODE
327
328    _LIBCPP_INLINE_VISIBILITY
329    reference operator*() const {
330        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
331                             "Attempted to dereference a non-dereferenceable unordered container iterator");
332        return __node_->__upcast()->__value_;
333    }
334
335    _LIBCPP_INLINE_VISIBILITY
336    pointer operator->() const {
337        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
338                           "Attempted to dereference a non-dereferenceable unordered container iterator");
339        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
340    }
341
342    _LIBCPP_INLINE_VISIBILITY
343    __hash_iterator& operator++() {
344        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
345                       "Attempted to increment a non-incrementable unordered container iterator");
346        __node_ = __node_->__next_;
347        return *this;
348    }
349
350    _LIBCPP_INLINE_VISIBILITY
351    __hash_iterator operator++(int)
352    {
353        __hash_iterator __t(*this);
354        ++(*this);
355        return __t;
356    }
357
358    friend _LIBCPP_INLINE_VISIBILITY
359    bool operator==(const __hash_iterator& __x, const __hash_iterator& __y)
360    {
361        return __x.__node_ == __y.__node_;
362    }
363    friend _LIBCPP_INLINE_VISIBILITY
364    bool operator!=(const __hash_iterator& __x, const __hash_iterator& __y)
365        {return !(__x == __y);}
366
367private:
368    _LIBCPP_INLINE_VISIBILITY
369    explicit __hash_iterator(__next_pointer __node, const void* __c) _NOEXCEPT
370        : __node_(__node)
371        {
372            (void)__c;
373#ifdef _LIBCPP_ENABLE_DEBUG_MODE
374            __get_db()->__insert_ic(this, __c);
375#endif
376        }
377    template <class, class, class, class> friend class __hash_table;
378    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
379    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
380    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
381    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
382};
383
384template <class _NodePtr>
385class _LIBCPP_TEMPLATE_VIS __hash_const_iterator
386{
387    static_assert(!is_const<typename pointer_traits<_NodePtr>::element_type>::value, "");
388    typedef __hash_node_types<_NodePtr> _NodeTypes;
389    typedef _NodePtr                            __node_pointer;
390    typedef typename _NodeTypes::__next_pointer __next_pointer;
391
392    __next_pointer __node_;
393
394public:
395    typedef __hash_iterator<_NodePtr> __non_const_iterator;
396
397    typedef forward_iterator_tag                                 iterator_category;
398    typedef typename _NodeTypes::__node_value_type               value_type;
399    typedef typename _NodeTypes::difference_type                 difference_type;
400    typedef const value_type&                                    reference;
401    typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
402
403
404    _LIBCPP_INLINE_VISIBILITY __hash_const_iterator() _NOEXCEPT : __node_(nullptr) {
405        _VSTD::__debug_db_insert_i(this);
406    }
407
408    _LIBCPP_INLINE_VISIBILITY
409    __hash_const_iterator(const __non_const_iterator& __x) _NOEXCEPT
410        : __node_(__x.__node_)
411    {
412#ifdef _LIBCPP_ENABLE_DEBUG_MODE
413        __get_db()->__iterator_copy(this, _VSTD::addressof(__x));
414#endif
415    }
416
417#ifdef _LIBCPP_ENABLE_DEBUG_MODE
418    _LIBCPP_INLINE_VISIBILITY
419    __hash_const_iterator(const __hash_const_iterator& __i)
420        : __node_(__i.__node_)
421    {
422        __get_db()->__iterator_copy(this, _VSTD::addressof(__i));
423    }
424
425    _LIBCPP_INLINE_VISIBILITY
426    ~__hash_const_iterator()
427    {
428        __get_db()->__erase_i(this);
429    }
430
431    _LIBCPP_INLINE_VISIBILITY
432    __hash_const_iterator& operator=(const __hash_const_iterator& __i)
433    {
434        if (this != _VSTD::addressof(__i))
435        {
436            __get_db()->__iterator_copy(this, _VSTD::addressof(__i));
437            __node_ = __i.__node_;
438        }
439        return *this;
440    }
441#endif // _LIBCPP_ENABLE_DEBUG_MODE
442
443    _LIBCPP_INLINE_VISIBILITY
444    reference operator*() const {
445        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
446                           "Attempted to dereference a non-dereferenceable unordered container const_iterator");
447        return __node_->__upcast()->__value_;
448    }
449    _LIBCPP_INLINE_VISIBILITY
450    pointer operator->() const {
451        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
452                           "Attempted to dereference a non-dereferenceable unordered container const_iterator");
453        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
454    }
455
456    _LIBCPP_INLINE_VISIBILITY
457    __hash_const_iterator& operator++() {
458        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
459                             "Attempted to increment a non-incrementable unordered container const_iterator");
460        __node_ = __node_->__next_;
461        return *this;
462    }
463
464    _LIBCPP_INLINE_VISIBILITY
465    __hash_const_iterator operator++(int)
466    {
467        __hash_const_iterator __t(*this);
468        ++(*this);
469        return __t;
470    }
471
472    friend _LIBCPP_INLINE_VISIBILITY
473    bool operator==(const __hash_const_iterator& __x, const __hash_const_iterator& __y)
474    {
475        return __x.__node_ == __y.__node_;
476    }
477    friend _LIBCPP_INLINE_VISIBILITY
478    bool operator!=(const __hash_const_iterator& __x, const __hash_const_iterator& __y)
479        {return !(__x == __y);}
480
481private:
482    _LIBCPP_INLINE_VISIBILITY
483    explicit __hash_const_iterator(__next_pointer __node, const void* __c) _NOEXCEPT
484        : __node_(__node)
485        {
486            (void)__c;
487#ifdef _LIBCPP_ENABLE_DEBUG_MODE
488            __get_db()->__insert_ic(this, __c);
489#endif
490        }
491    template <class, class, class, class> friend class __hash_table;
492    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
493    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
494    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
495};
496
497template <class _NodePtr>
498class _LIBCPP_TEMPLATE_VIS __hash_local_iterator
499{
500    typedef __hash_node_types<_NodePtr> _NodeTypes;
501    typedef _NodePtr                            __node_pointer;
502    typedef typename _NodeTypes::__next_pointer __next_pointer;
503
504    __next_pointer         __node_;
505    size_t                 __bucket_;
506    size_t                 __bucket_count_;
507
508public:
509    typedef forward_iterator_tag                                iterator_category;
510    typedef typename _NodeTypes::__node_value_type              value_type;
511    typedef typename _NodeTypes::difference_type                difference_type;
512    typedef value_type&                                         reference;
513    typedef typename _NodeTypes::__node_value_type_pointer      pointer;
514
515    _LIBCPP_INLINE_VISIBILITY __hash_local_iterator() _NOEXCEPT : __node_(nullptr) {
516        _VSTD::__debug_db_insert_i(this);
517    }
518
519#ifdef _LIBCPP_ENABLE_DEBUG_MODE
520    _LIBCPP_INLINE_VISIBILITY
521    __hash_local_iterator(const __hash_local_iterator& __i)
522        : __node_(__i.__node_),
523          __bucket_(__i.__bucket_),
524          __bucket_count_(__i.__bucket_count_)
525    {
526        __get_db()->__iterator_copy(this, _VSTD::addressof(__i));
527    }
528
529    _LIBCPP_INLINE_VISIBILITY
530    ~__hash_local_iterator()
531    {
532        __get_db()->__erase_i(this);
533    }
534
535    _LIBCPP_INLINE_VISIBILITY
536    __hash_local_iterator& operator=(const __hash_local_iterator& __i)
537    {
538        if (this != _VSTD::addressof(__i))
539        {
540            __get_db()->__iterator_copy(this, _VSTD::addressof(__i));
541            __node_ = __i.__node_;
542            __bucket_ = __i.__bucket_;
543            __bucket_count_ = __i.__bucket_count_;
544        }
545        return *this;
546    }
547#endif // _LIBCPP_ENABLE_DEBUG_MODE
548
549    _LIBCPP_INLINE_VISIBILITY
550    reference operator*() const {
551        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
552                           "Attempted to dereference a non-dereferenceable unordered container local_iterator");
553        return __node_->__upcast()->__value_;
554    }
555
556    _LIBCPP_INLINE_VISIBILITY
557    pointer operator->() const {
558        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
559                             "Attempted to dereference a non-dereferenceable unordered container local_iterator");
560        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
561    }
562
563    _LIBCPP_INLINE_VISIBILITY
564    __hash_local_iterator& operator++() {
565        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
566                       "Attempted to increment a non-incrementable unordered container local_iterator");
567        __node_ = __node_->__next_;
568        if (__node_ != nullptr && std::__constrain_hash(__node_->__hash(), __bucket_count_) != __bucket_)
569            __node_ = nullptr;
570        return *this;
571    }
572
573    _LIBCPP_INLINE_VISIBILITY
574    __hash_local_iterator operator++(int)
575    {
576        __hash_local_iterator __t(*this);
577        ++(*this);
578        return __t;
579    }
580
581    friend _LIBCPP_INLINE_VISIBILITY
582    bool operator==(const __hash_local_iterator& __x, const __hash_local_iterator& __y)
583    {
584        return __x.__node_ == __y.__node_;
585    }
586    friend _LIBCPP_INLINE_VISIBILITY
587    bool operator!=(const __hash_local_iterator& __x, const __hash_local_iterator& __y)
588        {return !(__x == __y);}
589
590private:
591    _LIBCPP_INLINE_VISIBILITY
592    explicit __hash_local_iterator(__next_pointer __node, size_t __bucket,
593                                   size_t __bucket_count, const void* __c) _NOEXCEPT
594        : __node_(__node),
595          __bucket_(__bucket),
596          __bucket_count_(__bucket_count)
597        {
598            (void)__c;
599#ifdef _LIBCPP_ENABLE_DEBUG_MODE
600            __get_db()->__insert_ic(this, __c);
601#endif
602            if (__node_ != nullptr)
603                __node_ = __node_->__next_;
604        }
605    template <class, class, class, class> friend class __hash_table;
606    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
607    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
608};
609
610template <class _ConstNodePtr>
611class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator
612{
613    typedef __hash_node_types<_ConstNodePtr> _NodeTypes;
614    typedef _ConstNodePtr                       __node_pointer;
615    typedef typename _NodeTypes::__next_pointer __next_pointer;
616
617    __next_pointer         __node_;
618    size_t                 __bucket_;
619    size_t                 __bucket_count_;
620
621    typedef pointer_traits<__node_pointer>          __pointer_traits;
622    typedef typename __pointer_traits::element_type __node;
623    typedef __remove_const_t<__node>                  __non_const_node;
624    typedef __rebind_pointer_t<__node_pointer, __non_const_node>
625        __non_const_node_pointer;
626public:
627    typedef __hash_local_iterator<__non_const_node_pointer>
628                                                    __non_const_iterator;
629
630    typedef forward_iterator_tag                                 iterator_category;
631    typedef typename _NodeTypes::__node_value_type               value_type;
632    typedef typename _NodeTypes::difference_type                 difference_type;
633    typedef const value_type&                                    reference;
634    typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
635
636
637    _LIBCPP_INLINE_VISIBILITY __hash_const_local_iterator() _NOEXCEPT : __node_(nullptr) {
638        _VSTD::__debug_db_insert_i(this);
639    }
640
641    _LIBCPP_INLINE_VISIBILITY
642    __hash_const_local_iterator(const __non_const_iterator& __x) _NOEXCEPT
643        : __node_(__x.__node_),
644          __bucket_(__x.__bucket_),
645          __bucket_count_(__x.__bucket_count_)
646    {
647#ifdef _LIBCPP_ENABLE_DEBUG_MODE
648        __get_db()->__iterator_copy(this, _VSTD::addressof(__x));
649#endif
650    }
651
652#ifdef _LIBCPP_ENABLE_DEBUG_MODE
653    _LIBCPP_INLINE_VISIBILITY
654    __hash_const_local_iterator(const __hash_const_local_iterator& __i)
655        : __node_(__i.__node_),
656          __bucket_(__i.__bucket_),
657          __bucket_count_(__i.__bucket_count_)
658    {
659        __get_db()->__iterator_copy(this, _VSTD::addressof(__i));
660    }
661
662    _LIBCPP_INLINE_VISIBILITY
663    ~__hash_const_local_iterator()
664    {
665        __get_db()->__erase_i(this);
666    }
667
668    _LIBCPP_INLINE_VISIBILITY
669    __hash_const_local_iterator& operator=(const __hash_const_local_iterator& __i)
670    {
671        if (this != _VSTD::addressof(__i))
672        {
673            __get_db()->__iterator_copy(this, _VSTD::addressof(__i));
674            __node_ = __i.__node_;
675            __bucket_ = __i.__bucket_;
676            __bucket_count_ = __i.__bucket_count_;
677        }
678        return *this;
679    }
680#endif // _LIBCPP_ENABLE_DEBUG_MODE
681
682    _LIBCPP_INLINE_VISIBILITY
683    reference operator*() const {
684        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
685                           "Attempted to dereference a non-dereferenceable unordered container const_local_iterator");
686        return __node_->__upcast()->__value_;
687    }
688
689    _LIBCPP_INLINE_VISIBILITY
690    pointer operator->() const {
691        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
692                           "Attempted to dereference a non-dereferenceable unordered container const_local_iterator");
693        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
694    }
695
696    _LIBCPP_INLINE_VISIBILITY
697    __hash_const_local_iterator& operator++() {
698        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
699                       "Attempted to increment a non-incrementable unordered container const_local_iterator");
700        __node_ = __node_->__next_;
701        if (__node_ != nullptr && std::__constrain_hash(__node_->__hash(), __bucket_count_) != __bucket_)
702            __node_ = nullptr;
703        return *this;
704    }
705
706    _LIBCPP_INLINE_VISIBILITY
707    __hash_const_local_iterator operator++(int)
708    {
709        __hash_const_local_iterator __t(*this);
710        ++(*this);
711        return __t;
712    }
713
714    friend _LIBCPP_INLINE_VISIBILITY
715    bool operator==(const __hash_const_local_iterator& __x, const __hash_const_local_iterator& __y)
716    {
717        return __x.__node_ == __y.__node_;
718    }
719    friend _LIBCPP_INLINE_VISIBILITY
720    bool operator!=(const __hash_const_local_iterator& __x, const __hash_const_local_iterator& __y)
721        {return !(__x == __y);}
722
723private:
724    _LIBCPP_INLINE_VISIBILITY
725    explicit __hash_const_local_iterator(__next_pointer __node_ptr, size_t __bucket,
726                                         size_t __bucket_count, const void* __c) _NOEXCEPT
727        : __node_(__node_ptr),
728          __bucket_(__bucket),
729          __bucket_count_(__bucket_count)
730        {
731            (void)__c;
732#ifdef _LIBCPP_ENABLE_DEBUG_MODE
733            __get_db()->__insert_ic(this, __c);
734#endif
735            if (__node_ != nullptr)
736                __node_ = __node_->__next_;
737        }
738    template <class, class, class, class> friend class __hash_table;
739    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
740};
741
742template <class _Alloc>
743class __bucket_list_deallocator
744{
745    typedef _Alloc                                          allocator_type;
746    typedef allocator_traits<allocator_type>                __alloc_traits;
747    typedef typename __alloc_traits::size_type              size_type;
748
749    __compressed_pair<size_type, allocator_type> __data_;
750public:
751    typedef typename __alloc_traits::pointer pointer;
752
753    _LIBCPP_INLINE_VISIBILITY
754    __bucket_list_deallocator()
755        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
756        : __data_(0, __default_init_tag()) {}
757
758    _LIBCPP_INLINE_VISIBILITY
759    __bucket_list_deallocator(const allocator_type& __a, size_type __size)
760        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
761        : __data_(__size, __a) {}
762
763    _LIBCPP_INLINE_VISIBILITY
764    __bucket_list_deallocator(__bucket_list_deallocator&& __x)
765        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
766        : __data_(_VSTD::move(__x.__data_))
767    {
768        __x.size() = 0;
769    }
770
771    _LIBCPP_INLINE_VISIBILITY
772    size_type& size() _NOEXCEPT {return __data_.first();}
773    _LIBCPP_INLINE_VISIBILITY
774    size_type  size() const _NOEXCEPT {return __data_.first();}
775
776    _LIBCPP_INLINE_VISIBILITY
777    allocator_type& __alloc() _NOEXCEPT {return __data_.second();}
778    _LIBCPP_INLINE_VISIBILITY
779    const allocator_type& __alloc() const _NOEXCEPT {return __data_.second();}
780
781    _LIBCPP_INLINE_VISIBILITY
782    void operator()(pointer __p) _NOEXCEPT
783    {
784        __alloc_traits::deallocate(__alloc(), __p, size());
785    }
786};
787
788template <class _Alloc> class __hash_map_node_destructor;
789
790template <class _Alloc>
791class __hash_node_destructor
792{
793    typedef _Alloc                                          allocator_type;
794    typedef allocator_traits<allocator_type>                __alloc_traits;
795
796public:
797    typedef typename __alloc_traits::pointer                pointer;
798private:
799    typedef __hash_node_types<pointer> _NodeTypes;
800
801    allocator_type& __na_;
802
803public:
804    bool __value_constructed;
805
806    __hash_node_destructor(__hash_node_destructor const&) = default;
807    __hash_node_destructor& operator=(const __hash_node_destructor&) = delete;
808
809
810    _LIBCPP_INLINE_VISIBILITY
811    explicit __hash_node_destructor(allocator_type& __na,
812                                    bool __constructed = false) _NOEXCEPT
813        : __na_(__na),
814          __value_constructed(__constructed)
815        {}
816
817    _LIBCPP_INLINE_VISIBILITY
818    void operator()(pointer __p) _NOEXCEPT
819    {
820        if (__value_constructed)
821            __alloc_traits::destroy(__na_, _NodeTypes::__get_ptr(__p->__value_));
822        if (__p)
823            __alloc_traits::deallocate(__na_, __p, 1);
824    }
825
826    template <class> friend class __hash_map_node_destructor;
827};
828
829#if _LIBCPP_STD_VER > 14
830template <class _NodeType, class _Alloc>
831struct __generic_container_node_destructor;
832
833template <class _Tp, class _VoidPtr, class _Alloc>
834struct __generic_container_node_destructor<__hash_node<_Tp, _VoidPtr>, _Alloc>
835    : __hash_node_destructor<_Alloc>
836{
837    using __hash_node_destructor<_Alloc>::__hash_node_destructor;
838};
839#endif
840
841template <class _Key, class _Hash, class _Equal>
842struct __enforce_unordered_container_requirements {
843#ifndef _LIBCPP_CXX03_LANG
844    static_assert(__check_hash_requirements<_Key, _Hash>::value,
845    "the specified hash does not meet the Hash requirements");
846    static_assert(is_copy_constructible<_Equal>::value,
847    "the specified comparator is required to be copy constructible");
848#endif
849    typedef int type;
850};
851
852template <class _Key, class _Hash, class _Equal>
853#ifndef _LIBCPP_CXX03_LANG
854    _LIBCPP_DIAGNOSE_WARNING(!__invokable<_Equal const&, _Key const&, _Key const&>::value,
855    "the specified comparator type does not provide a viable const call operator")
856    _LIBCPP_DIAGNOSE_WARNING(!__invokable<_Hash const&, _Key const&>::value,
857    "the specified hash functor does not provide a viable const call operator")
858#endif
859typename __enforce_unordered_container_requirements<_Key, _Hash, _Equal>::type
860__diagnose_unordered_container_requirements(int);
861
862// This dummy overload is used so that the compiler won't emit a spurious
863// "no matching function for call to __diagnose_unordered_xxx" diagnostic
864// when the overload above causes a hard error.
865template <class _Key, class _Hash, class _Equal>
866int __diagnose_unordered_container_requirements(void*);
867
868template <class _Tp, class _Hash, class _Equal, class _Alloc>
869class __hash_table
870{
871public:
872    typedef _Tp    value_type;
873    typedef _Hash  hasher;
874    typedef _Equal key_equal;
875    typedef _Alloc allocator_type;
876
877private:
878    typedef allocator_traits<allocator_type> __alloc_traits;
879    typedef typename
880      __make_hash_node_types<value_type, typename __alloc_traits::void_pointer>::type
881                                                                     _NodeTypes;
882public:
883
884    typedef typename _NodeTypes::__node_value_type           __node_value_type;
885    typedef typename _NodeTypes::__container_value_type      __container_value_type;
886    typedef typename _NodeTypes::key_type                    key_type;
887    typedef value_type&                              reference;
888    typedef const value_type&                        const_reference;
889    typedef typename __alloc_traits::pointer         pointer;
890    typedef typename __alloc_traits::const_pointer   const_pointer;
891#ifndef _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
892    typedef typename __alloc_traits::size_type       size_type;
893#else
894    typedef typename _NodeTypes::size_type           size_type;
895#endif
896    typedef typename _NodeTypes::difference_type     difference_type;
897public:
898    // Create __node
899
900    typedef typename _NodeTypes::__node_type __node;
901    typedef __rebind_alloc<__alloc_traits, __node>   __node_allocator;
902    typedef allocator_traits<__node_allocator>       __node_traits;
903    typedef typename _NodeTypes::__void_pointer      __void_pointer;
904    typedef typename _NodeTypes::__node_pointer      __node_pointer;
905    typedef typename _NodeTypes::__node_pointer      __node_const_pointer;
906    typedef typename _NodeTypes::__node_base_type    __first_node;
907    typedef typename _NodeTypes::__node_base_pointer __node_base_pointer;
908    typedef typename _NodeTypes::__next_pointer      __next_pointer;
909
910private:
911    // check for sane allocator pointer rebinding semantics. Rebinding the
912    // allocator for a new pointer type should be exactly the same as rebinding
913    // the pointer using 'pointer_traits'.
914    static_assert((is_same<__node_pointer, typename __node_traits::pointer>::value),
915                  "Allocator does not rebind pointers in a sane manner.");
916    typedef __rebind_alloc<__node_traits, __first_node> __node_base_allocator;
917    typedef allocator_traits<__node_base_allocator> __node_base_traits;
918    static_assert((is_same<__node_base_pointer, typename __node_base_traits::pointer>::value),
919                 "Allocator does not rebind pointers in a sane manner.");
920
921private:
922
923    typedef __rebind_alloc<__node_traits, __next_pointer>  __pointer_allocator;
924    typedef __bucket_list_deallocator<__pointer_allocator> __bucket_list_deleter;
925    typedef unique_ptr<__next_pointer[], __bucket_list_deleter> __bucket_list;
926    typedef allocator_traits<__pointer_allocator>          __pointer_alloc_traits;
927    typedef typename __bucket_list_deleter::pointer       __node_pointer_pointer;
928
929    // --- Member data begin ---
930    __bucket_list                                         __bucket_list_;
931    __compressed_pair<__first_node, __node_allocator>     __p1_;
932    __compressed_pair<size_type, hasher>                  __p2_;
933    __compressed_pair<float, key_equal>                   __p3_;
934    // --- Member data end ---
935
936    _LIBCPP_INLINE_VISIBILITY
937    size_type& size() _NOEXCEPT {return __p2_.first();}
938public:
939    _LIBCPP_INLINE_VISIBILITY
940    size_type  size() const _NOEXCEPT {return __p2_.first();}
941
942    _LIBCPP_INLINE_VISIBILITY
943    hasher& hash_function() _NOEXCEPT {return __p2_.second();}
944    _LIBCPP_INLINE_VISIBILITY
945    const hasher& hash_function() const _NOEXCEPT {return __p2_.second();}
946
947    _LIBCPP_INLINE_VISIBILITY
948    float& max_load_factor() _NOEXCEPT {return __p3_.first();}
949    _LIBCPP_INLINE_VISIBILITY
950    float  max_load_factor() const _NOEXCEPT {return __p3_.first();}
951
952    _LIBCPP_INLINE_VISIBILITY
953    key_equal& key_eq() _NOEXCEPT {return __p3_.second();}
954    _LIBCPP_INLINE_VISIBILITY
955    const key_equal& key_eq() const _NOEXCEPT {return __p3_.second();}
956
957    _LIBCPP_INLINE_VISIBILITY
958    __node_allocator& __node_alloc() _NOEXCEPT {return __p1_.second();}
959    _LIBCPP_INLINE_VISIBILITY
960    const __node_allocator& __node_alloc() const _NOEXCEPT
961        {return __p1_.second();}
962
963public:
964    typedef __hash_iterator<__node_pointer>                   iterator;
965    typedef __hash_const_iterator<__node_pointer>             const_iterator;
966    typedef __hash_local_iterator<__node_pointer>             local_iterator;
967    typedef __hash_const_local_iterator<__node_pointer>       const_local_iterator;
968
969    _LIBCPP_INLINE_VISIBILITY
970    __hash_table()
971        _NOEXCEPT_(
972            is_nothrow_default_constructible<__bucket_list>::value &&
973            is_nothrow_default_constructible<__first_node>::value &&
974            is_nothrow_default_constructible<__node_allocator>::value &&
975            is_nothrow_default_constructible<hasher>::value &&
976            is_nothrow_default_constructible<key_equal>::value);
977    _LIBCPP_INLINE_VISIBILITY
978    __hash_table(const hasher& __hf, const key_equal& __eql);
979    __hash_table(const hasher& __hf, const key_equal& __eql,
980                 const allocator_type& __a);
981    explicit __hash_table(const allocator_type& __a);
982    __hash_table(const __hash_table& __u);
983    __hash_table(const __hash_table& __u, const allocator_type& __a);
984    __hash_table(__hash_table&& __u)
985        _NOEXCEPT_(
986            is_nothrow_move_constructible<__bucket_list>::value &&
987            is_nothrow_move_constructible<__first_node>::value &&
988            is_nothrow_move_constructible<__node_allocator>::value &&
989            is_nothrow_move_constructible<hasher>::value &&
990            is_nothrow_move_constructible<key_equal>::value);
991    __hash_table(__hash_table&& __u, const allocator_type& __a);
992    ~__hash_table();
993
994    __hash_table& operator=(const __hash_table& __u);
995    _LIBCPP_INLINE_VISIBILITY
996    __hash_table& operator=(__hash_table&& __u)
997        _NOEXCEPT_(
998            __node_traits::propagate_on_container_move_assignment::value &&
999            is_nothrow_move_assignable<__node_allocator>::value &&
1000            is_nothrow_move_assignable<hasher>::value &&
1001            is_nothrow_move_assignable<key_equal>::value);
1002    template <class _InputIterator>
1003        void __assign_unique(_InputIterator __first, _InputIterator __last);
1004    template <class _InputIterator>
1005        void __assign_multi(_InputIterator __first, _InputIterator __last);
1006
1007    _LIBCPP_INLINE_VISIBILITY
1008    size_type max_size() const _NOEXCEPT
1009    {
1010        return _VSTD::min<size_type>(
1011            __node_traits::max_size(__node_alloc()),
1012            numeric_limits<difference_type >::max()
1013        );
1014    }
1015
1016private:
1017    _LIBCPP_INLINE_VISIBILITY
1018    __next_pointer __node_insert_multi_prepare(size_t __cp_hash,
1019                                               value_type& __cp_val);
1020    _LIBCPP_INLINE_VISIBILITY
1021    void __node_insert_multi_perform(__node_pointer __cp,
1022                                     __next_pointer __pn) _NOEXCEPT;
1023
1024    _LIBCPP_INLINE_VISIBILITY
1025    __next_pointer __node_insert_unique_prepare(size_t __nd_hash,
1026                                                value_type& __nd_val);
1027    _LIBCPP_INLINE_VISIBILITY
1028    void __node_insert_unique_perform(__node_pointer __ptr) _NOEXCEPT;
1029
1030public:
1031    _LIBCPP_INLINE_VISIBILITY
1032    pair<iterator, bool> __node_insert_unique(__node_pointer __nd);
1033    _LIBCPP_INLINE_VISIBILITY
1034    iterator             __node_insert_multi(__node_pointer __nd);
1035    _LIBCPP_INLINE_VISIBILITY
1036    iterator             __node_insert_multi(const_iterator __p,
1037                                             __node_pointer __nd);
1038
1039    template <class _Key, class ..._Args>
1040    _LIBCPP_INLINE_VISIBILITY
1041    pair<iterator, bool> __emplace_unique_key_args(_Key const& __k, _Args&&... __args);
1042
1043    template <class... _Args>
1044    _LIBCPP_INLINE_VISIBILITY
1045    pair<iterator, bool> __emplace_unique_impl(_Args&&... __args);
1046
1047    template <class _Pp>
1048    _LIBCPP_INLINE_VISIBILITY
1049    pair<iterator, bool> __emplace_unique(_Pp&& __x) {
1050      return __emplace_unique_extract_key(_VSTD::forward<_Pp>(__x),
1051                                          __can_extract_key<_Pp, key_type>());
1052    }
1053
1054    template <class _First, class _Second>
1055    _LIBCPP_INLINE_VISIBILITY
1056    __enable_if_t<__can_extract_map_key<_First, key_type, __container_value_type>::value, pair<iterator, bool> >
1057    __emplace_unique(_First&& __f, _Second&& __s) {
1058        return __emplace_unique_key_args(__f, _VSTD::forward<_First>(__f),
1059                                              _VSTD::forward<_Second>(__s));
1060    }
1061
1062    template <class... _Args>
1063    _LIBCPP_INLINE_VISIBILITY
1064    pair<iterator, bool> __emplace_unique(_Args&&... __args) {
1065      return __emplace_unique_impl(_VSTD::forward<_Args>(__args)...);
1066    }
1067
1068    template <class _Pp>
1069    _LIBCPP_INLINE_VISIBILITY
1070    pair<iterator, bool>
1071    __emplace_unique_extract_key(_Pp&& __x, __extract_key_fail_tag) {
1072      return __emplace_unique_impl(_VSTD::forward<_Pp>(__x));
1073    }
1074    template <class _Pp>
1075    _LIBCPP_INLINE_VISIBILITY
1076    pair<iterator, bool>
1077    __emplace_unique_extract_key(_Pp&& __x, __extract_key_self_tag) {
1078      return __emplace_unique_key_args(__x, _VSTD::forward<_Pp>(__x));
1079    }
1080    template <class _Pp>
1081    _LIBCPP_INLINE_VISIBILITY
1082    pair<iterator, bool>
1083    __emplace_unique_extract_key(_Pp&& __x, __extract_key_first_tag) {
1084      return __emplace_unique_key_args(__x.first, _VSTD::forward<_Pp>(__x));
1085    }
1086
1087    template <class... _Args>
1088    _LIBCPP_INLINE_VISIBILITY
1089    iterator __emplace_multi(_Args&&... __args);
1090    template <class... _Args>
1091    _LIBCPP_INLINE_VISIBILITY
1092    iterator __emplace_hint_multi(const_iterator __p, _Args&&... __args);
1093
1094
1095    _LIBCPP_INLINE_VISIBILITY
1096    pair<iterator, bool>
1097    __insert_unique(__container_value_type&& __x) {
1098      return __emplace_unique_key_args(_NodeTypes::__get_key(__x), _VSTD::move(__x));
1099    }
1100
1101    template <class _Pp, class = __enable_if_t<!__is_same_uncvref<_Pp, __container_value_type>::value> >
1102    _LIBCPP_INLINE_VISIBILITY
1103    pair<iterator, bool> __insert_unique(_Pp&& __x) {
1104      return __emplace_unique(_VSTD::forward<_Pp>(__x));
1105    }
1106
1107    template <class _Pp>
1108    _LIBCPP_INLINE_VISIBILITY
1109    iterator __insert_multi(_Pp&& __x) {
1110      return __emplace_multi(_VSTD::forward<_Pp>(__x));
1111    }
1112
1113    template <class _Pp>
1114    _LIBCPP_INLINE_VISIBILITY
1115    iterator __insert_multi(const_iterator __p, _Pp&& __x) {
1116        return __emplace_hint_multi(__p, _VSTD::forward<_Pp>(__x));
1117    }
1118
1119    _LIBCPP_INLINE_VISIBILITY
1120    pair<iterator, bool> __insert_unique(const __container_value_type& __x) {
1121        return __emplace_unique_key_args(_NodeTypes::__get_key(__x), __x);
1122    }
1123
1124#if _LIBCPP_STD_VER > 14
1125    template <class _NodeHandle, class _InsertReturnType>
1126    _LIBCPP_INLINE_VISIBILITY
1127    _InsertReturnType __node_handle_insert_unique(_NodeHandle&& __nh);
1128    template <class _NodeHandle>
1129    _LIBCPP_INLINE_VISIBILITY
1130    iterator __node_handle_insert_unique(const_iterator __hint,
1131                                         _NodeHandle&& __nh);
1132    template <class _Table>
1133    _LIBCPP_INLINE_VISIBILITY
1134    void __node_handle_merge_unique(_Table& __source);
1135
1136    template <class _NodeHandle>
1137    _LIBCPP_INLINE_VISIBILITY
1138    iterator __node_handle_insert_multi(_NodeHandle&& __nh);
1139    template <class _NodeHandle>
1140    _LIBCPP_INLINE_VISIBILITY
1141    iterator __node_handle_insert_multi(const_iterator __hint, _NodeHandle&& __nh);
1142    template <class _Table>
1143    _LIBCPP_INLINE_VISIBILITY
1144    void __node_handle_merge_multi(_Table& __source);
1145
1146    template <class _NodeHandle>
1147    _LIBCPP_INLINE_VISIBILITY
1148    _NodeHandle __node_handle_extract(key_type const& __key);
1149    template <class _NodeHandle>
1150    _LIBCPP_INLINE_VISIBILITY
1151    _NodeHandle __node_handle_extract(const_iterator __it);
1152#endif
1153
1154    void clear() _NOEXCEPT;
1155    _LIBCPP_INLINE_VISIBILITY void __rehash_unique(size_type __n) { __rehash<true>(__n); }
1156    _LIBCPP_INLINE_VISIBILITY void __rehash_multi(size_type __n) { __rehash<false>(__n); }
1157    _LIBCPP_INLINE_VISIBILITY void __reserve_unique(size_type __n)
1158    {
1159        __rehash_unique(static_cast<size_type>(std::ceil(__n / max_load_factor())));
1160    }
1161    _LIBCPP_INLINE_VISIBILITY void __reserve_multi(size_type __n)
1162    {
1163        __rehash_multi(static_cast<size_type>(std::ceil(__n / max_load_factor())));
1164    }
1165
1166    _LIBCPP_INLINE_VISIBILITY
1167    size_type bucket_count() const _NOEXCEPT
1168    {
1169        return __bucket_list_.get_deleter().size();
1170    }
1171
1172    _LIBCPP_INLINE_VISIBILITY
1173    iterator       begin() _NOEXCEPT;
1174    _LIBCPP_INLINE_VISIBILITY
1175    iterator       end() _NOEXCEPT;
1176    _LIBCPP_INLINE_VISIBILITY
1177    const_iterator begin() const _NOEXCEPT;
1178    _LIBCPP_INLINE_VISIBILITY
1179    const_iterator end() const _NOEXCEPT;
1180
1181    template <class _Key>
1182        _LIBCPP_INLINE_VISIBILITY
1183        size_type bucket(const _Key& __k) const
1184        {
1185            _LIBCPP_ASSERT(bucket_count() > 0,
1186                "unordered container::bucket(key) called when bucket_count() == 0");
1187            return std::__constrain_hash(hash_function()(__k), bucket_count());
1188        }
1189
1190    template <class _Key>
1191        iterator       find(const _Key& __x);
1192    template <class _Key>
1193        const_iterator find(const _Key& __x) const;
1194
1195    typedef __hash_node_destructor<__node_allocator> _Dp;
1196    typedef unique_ptr<__node, _Dp> __node_holder;
1197
1198    iterator erase(const_iterator __p);
1199    iterator erase(const_iterator __first, const_iterator __last);
1200    template <class _Key>
1201        size_type __erase_unique(const _Key& __k);
1202    template <class _Key>
1203        size_type __erase_multi(const _Key& __k);
1204    __node_holder remove(const_iterator __p) _NOEXCEPT;
1205
1206    template <class _Key>
1207        _LIBCPP_INLINE_VISIBILITY
1208        size_type __count_unique(const _Key& __k) const;
1209    template <class _Key>
1210        size_type __count_multi(const _Key& __k) const;
1211
1212    template <class _Key>
1213        pair<iterator, iterator>
1214        __equal_range_unique(const _Key& __k);
1215    template <class _Key>
1216        pair<const_iterator, const_iterator>
1217        __equal_range_unique(const _Key& __k) const;
1218
1219    template <class _Key>
1220        pair<iterator, iterator>
1221        __equal_range_multi(const _Key& __k);
1222    template <class _Key>
1223        pair<const_iterator, const_iterator>
1224        __equal_range_multi(const _Key& __k) const;
1225
1226    void swap(__hash_table& __u)
1227#if _LIBCPP_STD_VER <= 11
1228        _NOEXCEPT_(
1229            __is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value
1230            && (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value
1231                  || __is_nothrow_swappable<__pointer_allocator>::value)
1232            && (!__node_traits::propagate_on_container_swap::value
1233                  || __is_nothrow_swappable<__node_allocator>::value)
1234            );
1235#else
1236     _NOEXCEPT_(__is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value);
1237#endif
1238
1239    _LIBCPP_INLINE_VISIBILITY
1240    size_type max_bucket_count() const _NOEXCEPT
1241        {return max_size(); }
1242    size_type bucket_size(size_type __n) const;
1243    _LIBCPP_INLINE_VISIBILITY float load_factor() const _NOEXCEPT
1244    {
1245        size_type __bc = bucket_count();
1246        return __bc != 0 ? (float)size() / __bc : 0.f;
1247    }
1248    _LIBCPP_INLINE_VISIBILITY void max_load_factor(float __mlf) _NOEXCEPT
1249    {
1250        _LIBCPP_ASSERT(__mlf > 0,
1251            "unordered container::max_load_factor(lf) called with lf <= 0");
1252        max_load_factor() = _VSTD::max(__mlf, load_factor());
1253    }
1254
1255    _LIBCPP_INLINE_VISIBILITY
1256    local_iterator
1257    begin(size_type __n)
1258    {
1259        _LIBCPP_ASSERT(__n < bucket_count(),
1260            "unordered container::begin(n) called with n >= bucket_count()");
1261        return local_iterator(__bucket_list_[__n], __n, bucket_count(), this);
1262    }
1263
1264    _LIBCPP_INLINE_VISIBILITY
1265    local_iterator
1266    end(size_type __n)
1267    {
1268        _LIBCPP_ASSERT(__n < bucket_count(),
1269            "unordered container::end(n) called with n >= bucket_count()");
1270        return local_iterator(nullptr, __n, bucket_count(), this);
1271    }
1272
1273    _LIBCPP_INLINE_VISIBILITY
1274    const_local_iterator
1275    cbegin(size_type __n) const
1276    {
1277        _LIBCPP_ASSERT(__n < bucket_count(),
1278            "unordered container::cbegin(n) called with n >= bucket_count()");
1279        return const_local_iterator(__bucket_list_[__n], __n, bucket_count(), this);
1280    }
1281
1282    _LIBCPP_INLINE_VISIBILITY
1283    const_local_iterator
1284    cend(size_type __n) const
1285    {
1286        _LIBCPP_ASSERT(__n < bucket_count(),
1287            "unordered container::cend(n) called with n >= bucket_count()");
1288        return const_local_iterator(nullptr, __n, bucket_count(), this);
1289    }
1290
1291#ifdef _LIBCPP_ENABLE_DEBUG_MODE
1292
1293    bool __dereferenceable(const const_iterator* __i) const;
1294    bool __decrementable(const const_iterator* __i) const;
1295    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
1296    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
1297
1298#endif // _LIBCPP_ENABLE_DEBUG_MODE
1299
1300private:
1301    template <bool _UniqueKeys> void __rehash(size_type __n);
1302    template <bool _UniqueKeys> void __do_rehash(size_type __n);
1303
1304    template <class ..._Args>
1305    __node_holder __construct_node(_Args&& ...__args);
1306
1307    template <class _First, class ..._Rest>
1308    __node_holder __construct_node_hash(size_t __hash, _First&& __f, _Rest&&... __rest);
1309
1310
1311    _LIBCPP_INLINE_VISIBILITY
1312    void __copy_assign_alloc(const __hash_table& __u)
1313        {__copy_assign_alloc(__u, integral_constant<bool,
1314             __node_traits::propagate_on_container_copy_assignment::value>());}
1315    void __copy_assign_alloc(const __hash_table& __u, true_type);
1316    _LIBCPP_INLINE_VISIBILITY
1317        void __copy_assign_alloc(const __hash_table&, false_type) {}
1318
1319    void __move_assign(__hash_table& __u, false_type);
1320    void __move_assign(__hash_table& __u, true_type)
1321        _NOEXCEPT_(
1322            is_nothrow_move_assignable<__node_allocator>::value &&
1323            is_nothrow_move_assignable<hasher>::value &&
1324            is_nothrow_move_assignable<key_equal>::value);
1325    _LIBCPP_INLINE_VISIBILITY
1326    void __move_assign_alloc(__hash_table& __u)
1327        _NOEXCEPT_(
1328            !__node_traits::propagate_on_container_move_assignment::value ||
1329            (is_nothrow_move_assignable<__pointer_allocator>::value &&
1330             is_nothrow_move_assignable<__node_allocator>::value))
1331        {__move_assign_alloc(__u, integral_constant<bool,
1332             __node_traits::propagate_on_container_move_assignment::value>());}
1333    _LIBCPP_INLINE_VISIBILITY
1334    void __move_assign_alloc(__hash_table& __u, true_type)
1335        _NOEXCEPT_(
1336            is_nothrow_move_assignable<__pointer_allocator>::value &&
1337            is_nothrow_move_assignable<__node_allocator>::value)
1338    {
1339        __bucket_list_.get_deleter().__alloc() =
1340                _VSTD::move(__u.__bucket_list_.get_deleter().__alloc());
1341        __node_alloc() = _VSTD::move(__u.__node_alloc());
1342    }
1343    _LIBCPP_INLINE_VISIBILITY
1344        void __move_assign_alloc(__hash_table&, false_type) _NOEXCEPT {}
1345
1346    void __deallocate_node(__next_pointer __np) _NOEXCEPT;
1347    __next_pointer __detach() _NOEXCEPT;
1348
1349    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
1350    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
1351};
1352
1353template <class _Tp, class _Hash, class _Equal, class _Alloc>
1354inline
1355__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table()
1356    _NOEXCEPT_(
1357        is_nothrow_default_constructible<__bucket_list>::value &&
1358        is_nothrow_default_constructible<__first_node>::value &&
1359        is_nothrow_default_constructible<__node_allocator>::value &&
1360        is_nothrow_default_constructible<hasher>::value &&
1361        is_nothrow_default_constructible<key_equal>::value)
1362    : __p2_(0, __default_init_tag()),
1363      __p3_(1.0f, __default_init_tag())
1364{
1365}
1366
1367template <class _Tp, class _Hash, class _Equal, class _Alloc>
1368inline
1369__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const hasher& __hf,
1370                                                       const key_equal& __eql)
1371    : __bucket_list_(nullptr, __bucket_list_deleter()),
1372      __p1_(),
1373      __p2_(0, __hf),
1374      __p3_(1.0f, __eql)
1375{
1376}
1377
1378template <class _Tp, class _Hash, class _Equal, class _Alloc>
1379__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const hasher& __hf,
1380                                                       const key_equal& __eql,
1381                                                       const allocator_type& __a)
1382    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1383      __p1_(__default_init_tag(), __node_allocator(__a)),
1384      __p2_(0, __hf),
1385      __p3_(1.0f, __eql)
1386{
1387}
1388
1389template <class _Tp, class _Hash, class _Equal, class _Alloc>
1390__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const allocator_type& __a)
1391    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1392      __p1_(__default_init_tag(), __node_allocator(__a)),
1393      __p2_(0, __default_init_tag()),
1394      __p3_(1.0f, __default_init_tag())
1395{
1396}
1397
1398template <class _Tp, class _Hash, class _Equal, class _Alloc>
1399__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u)
1400    : __bucket_list_(nullptr,
1401          __bucket_list_deleter(allocator_traits<__pointer_allocator>::
1402              select_on_container_copy_construction(
1403                  __u.__bucket_list_.get_deleter().__alloc()), 0)),
1404      __p1_(__default_init_tag(), allocator_traits<__node_allocator>::
1405          select_on_container_copy_construction(__u.__node_alloc())),
1406      __p2_(0, __u.hash_function()),
1407      __p3_(__u.__p3_)
1408{
1409}
1410
1411template <class _Tp, class _Hash, class _Equal, class _Alloc>
1412__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u,
1413                                                       const allocator_type& __a)
1414    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1415      __p1_(__default_init_tag(), __node_allocator(__a)),
1416      __p2_(0, __u.hash_function()),
1417      __p3_(__u.__p3_)
1418{
1419}
1420
1421template <class _Tp, class _Hash, class _Equal, class _Alloc>
1422__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u)
1423        _NOEXCEPT_(
1424            is_nothrow_move_constructible<__bucket_list>::value &&
1425            is_nothrow_move_constructible<__first_node>::value &&
1426            is_nothrow_move_constructible<__node_allocator>::value &&
1427            is_nothrow_move_constructible<hasher>::value &&
1428            is_nothrow_move_constructible<key_equal>::value)
1429    : __bucket_list_(_VSTD::move(__u.__bucket_list_)),
1430      __p1_(_VSTD::move(__u.__p1_)),
1431      __p2_(_VSTD::move(__u.__p2_)),
1432      __p3_(_VSTD::move(__u.__p3_))
1433{
1434    if (size() > 0)
1435    {
1436        __bucket_list_[std::__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
1437            __p1_.first().__ptr();
1438        __u.__p1_.first().__next_ = nullptr;
1439        __u.size() = 0;
1440    }
1441}
1442
1443template <class _Tp, class _Hash, class _Equal, class _Alloc>
1444__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u,
1445                                                       const allocator_type& __a)
1446    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1447      __p1_(__default_init_tag(), __node_allocator(__a)),
1448      __p2_(0, _VSTD::move(__u.hash_function())),
1449      __p3_(_VSTD::move(__u.__p3_))
1450{
1451    if (__a == allocator_type(__u.__node_alloc()))
1452    {
1453        __bucket_list_.reset(__u.__bucket_list_.release());
1454        __bucket_list_.get_deleter().size() = __u.__bucket_list_.get_deleter().size();
1455        __u.__bucket_list_.get_deleter().size() = 0;
1456        if (__u.size() > 0)
1457        {
1458            __p1_.first().__next_ = __u.__p1_.first().__next_;
1459            __u.__p1_.first().__next_ = nullptr;
1460            __bucket_list_[std::__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
1461                __p1_.first().__ptr();
1462            size() = __u.size();
1463            __u.size() = 0;
1464        }
1465    }
1466}
1467
1468template <class _Tp, class _Hash, class _Equal, class _Alloc>
1469__hash_table<_Tp, _Hash, _Equal, _Alloc>::~__hash_table()
1470{
1471#if defined(_LIBCPP_CXX03_LANG)
1472    static_assert((is_copy_constructible<key_equal>::value),
1473                 "Predicate must be copy-constructible.");
1474    static_assert((is_copy_constructible<hasher>::value),
1475                 "Hasher must be copy-constructible.");
1476#endif
1477
1478    __deallocate_node(__p1_.first().__next_);
1479    std::__debug_db_erase_c(this);
1480}
1481
1482template <class _Tp, class _Hash, class _Equal, class _Alloc>
1483void
1484__hash_table<_Tp, _Hash, _Equal, _Alloc>::__copy_assign_alloc(
1485        const __hash_table& __u, true_type)
1486{
1487    if (__node_alloc() != __u.__node_alloc())
1488    {
1489        clear();
1490        __bucket_list_.reset();
1491        __bucket_list_.get_deleter().size() = 0;
1492    }
1493    __bucket_list_.get_deleter().__alloc() = __u.__bucket_list_.get_deleter().__alloc();
1494    __node_alloc() = __u.__node_alloc();
1495}
1496
1497template <class _Tp, class _Hash, class _Equal, class _Alloc>
1498__hash_table<_Tp, _Hash, _Equal, _Alloc>&
1499__hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(const __hash_table& __u)
1500{
1501    if (this != _VSTD::addressof(__u))
1502    {
1503        __copy_assign_alloc(__u);
1504        hash_function() = __u.hash_function();
1505        key_eq() = __u.key_eq();
1506        max_load_factor() = __u.max_load_factor();
1507        __assign_multi(__u.begin(), __u.end());
1508    }
1509    return *this;
1510}
1511
1512template <class _Tp, class _Hash, class _Equal, class _Alloc>
1513void
1514__hash_table<_Tp, _Hash, _Equal, _Alloc>::__deallocate_node(__next_pointer __np)
1515    _NOEXCEPT
1516{
1517    __node_allocator& __na = __node_alloc();
1518    while (__np != nullptr)
1519    {
1520        __next_pointer __next = __np->__next_;
1521#ifdef _LIBCPP_ENABLE_DEBUG_MODE
1522        __c_node* __c = __get_db()->__find_c_and_lock(this);
1523        for (__i_node** __p = __c->end_; __p != __c->beg_; )
1524        {
1525            --__p;
1526            iterator* __i = static_cast<iterator*>((*__p)->__i_);
1527            if (__i->__node_ == __np)
1528            {
1529                (*__p)->__c_ = nullptr;
1530                if (--__c->end_ != __p)
1531                    _VSTD::memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
1532            }
1533        }
1534        __get_db()->unlock();
1535#endif
1536        __node_pointer __real_np = __np->__upcast();
1537        __node_traits::destroy(__na, _NodeTypes::__get_ptr(__real_np->__value_));
1538        __node_traits::deallocate(__na, __real_np, 1);
1539        __np = __next;
1540    }
1541}
1542
1543template <class _Tp, class _Hash, class _Equal, class _Alloc>
1544typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1545__hash_table<_Tp, _Hash, _Equal, _Alloc>::__detach() _NOEXCEPT
1546{
1547    size_type __bc = bucket_count();
1548    for (size_type __i = 0; __i < __bc; ++__i)
1549        __bucket_list_[__i] = nullptr;
1550    size() = 0;
1551    __next_pointer __cache = __p1_.first().__next_;
1552    __p1_.first().__next_ = nullptr;
1553    return __cache;
1554}
1555
1556template <class _Tp, class _Hash, class _Equal, class _Alloc>
1557void
1558__hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(
1559        __hash_table& __u, true_type)
1560    _NOEXCEPT_(
1561        is_nothrow_move_assignable<__node_allocator>::value &&
1562        is_nothrow_move_assignable<hasher>::value &&
1563        is_nothrow_move_assignable<key_equal>::value)
1564{
1565    clear();
1566    __bucket_list_.reset(__u.__bucket_list_.release());
1567    __bucket_list_.get_deleter().size() = __u.__bucket_list_.get_deleter().size();
1568    __u.__bucket_list_.get_deleter().size() = 0;
1569    __move_assign_alloc(__u);
1570    size() = __u.size();
1571    hash_function() = _VSTD::move(__u.hash_function());
1572    max_load_factor() = __u.max_load_factor();
1573    key_eq() = _VSTD::move(__u.key_eq());
1574    __p1_.first().__next_ = __u.__p1_.first().__next_;
1575    if (size() > 0)
1576    {
1577        __bucket_list_[std::__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
1578            __p1_.first().__ptr();
1579        __u.__p1_.first().__next_ = nullptr;
1580        __u.size() = 0;
1581    }
1582    std::__debug_db_swap(this, std::addressof(__u));
1583}
1584
1585template <class _Tp, class _Hash, class _Equal, class _Alloc>
1586void
1587__hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(
1588        __hash_table& __u, false_type)
1589{
1590    if (__node_alloc() == __u.__node_alloc())
1591        __move_assign(__u, true_type());
1592    else
1593    {
1594        hash_function() = _VSTD::move(__u.hash_function());
1595        key_eq() = _VSTD::move(__u.key_eq());
1596        max_load_factor() = __u.max_load_factor();
1597        if (bucket_count() != 0)
1598        {
1599            __next_pointer __cache = __detach();
1600#ifndef _LIBCPP_NO_EXCEPTIONS
1601            try
1602            {
1603#endif // _LIBCPP_NO_EXCEPTIONS
1604                const_iterator __i = __u.begin();
1605                while (__cache != nullptr && __u.size() != 0)
1606                {
1607                    __cache->__upcast()->__value_ =
1608                        _VSTD::move(__u.remove(__i++)->__value_);
1609                    __next_pointer __next = __cache->__next_;
1610                    __node_insert_multi(__cache->__upcast());
1611                    __cache = __next;
1612                }
1613#ifndef _LIBCPP_NO_EXCEPTIONS
1614            }
1615            catch (...)
1616            {
1617                __deallocate_node(__cache);
1618                throw;
1619            }
1620#endif // _LIBCPP_NO_EXCEPTIONS
1621            __deallocate_node(__cache);
1622        }
1623        const_iterator __i = __u.begin();
1624        while (__u.size() != 0)
1625        {
1626            __node_holder __h = __construct_node(_NodeTypes::__move(__u.remove(__i++)->__value_));
1627            __node_insert_multi(__h.get());
1628            __h.release();
1629        }
1630    }
1631}
1632
1633template <class _Tp, class _Hash, class _Equal, class _Alloc>
1634inline
1635__hash_table<_Tp, _Hash, _Equal, _Alloc>&
1636__hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(__hash_table&& __u)
1637    _NOEXCEPT_(
1638        __node_traits::propagate_on_container_move_assignment::value &&
1639        is_nothrow_move_assignable<__node_allocator>::value &&
1640        is_nothrow_move_assignable<hasher>::value &&
1641        is_nothrow_move_assignable<key_equal>::value)
1642{
1643    __move_assign(__u, integral_constant<bool,
1644                  __node_traits::propagate_on_container_move_assignment::value>());
1645    return *this;
1646}
1647
1648template <class _Tp, class _Hash, class _Equal, class _Alloc>
1649template <class _InputIterator>
1650void
1651__hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_unique(_InputIterator __first,
1652                                                          _InputIterator __last)
1653{
1654    typedef iterator_traits<_InputIterator> _ITraits;
1655    typedef typename _ITraits::value_type _ItValueType;
1656    static_assert((is_same<_ItValueType, __container_value_type>::value),
1657                  "__assign_unique may only be called with the containers value type");
1658
1659    if (bucket_count() != 0)
1660    {
1661        __next_pointer __cache = __detach();
1662#ifndef _LIBCPP_NO_EXCEPTIONS
1663        try
1664        {
1665#endif // _LIBCPP_NO_EXCEPTIONS
1666            for (; __cache != nullptr && __first != __last; ++__first)
1667            {
1668                __cache->__upcast()->__value_ = *__first;
1669                __next_pointer __next = __cache->__next_;
1670                __node_insert_unique(__cache->__upcast());
1671                __cache = __next;
1672            }
1673#ifndef _LIBCPP_NO_EXCEPTIONS
1674        }
1675        catch (...)
1676        {
1677            __deallocate_node(__cache);
1678            throw;
1679        }
1680#endif // _LIBCPP_NO_EXCEPTIONS
1681        __deallocate_node(__cache);
1682    }
1683    for (; __first != __last; ++__first)
1684        __insert_unique(*__first);
1685}
1686
1687template <class _Tp, class _Hash, class _Equal, class _Alloc>
1688template <class _InputIterator>
1689void
1690__hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_multi(_InputIterator __first,
1691                                                         _InputIterator __last)
1692{
1693    typedef iterator_traits<_InputIterator> _ITraits;
1694    typedef typename _ITraits::value_type _ItValueType;
1695    static_assert((is_same<_ItValueType, __container_value_type>::value ||
1696                  is_same<_ItValueType, __node_value_type>::value),
1697                  "__assign_multi may only be called with the containers value type"
1698                  " or the nodes value type");
1699    if (bucket_count() != 0)
1700    {
1701        __next_pointer __cache = __detach();
1702#ifndef _LIBCPP_NO_EXCEPTIONS
1703        try
1704        {
1705#endif // _LIBCPP_NO_EXCEPTIONS
1706            for (; __cache != nullptr && __first != __last; ++__first)
1707            {
1708                __cache->__upcast()->__value_ = *__first;
1709                __next_pointer __next = __cache->__next_;
1710                __node_insert_multi(__cache->__upcast());
1711                __cache = __next;
1712            }
1713#ifndef _LIBCPP_NO_EXCEPTIONS
1714        }
1715        catch (...)
1716        {
1717            __deallocate_node(__cache);
1718            throw;
1719        }
1720#endif // _LIBCPP_NO_EXCEPTIONS
1721        __deallocate_node(__cache);
1722    }
1723    for (; __first != __last; ++__first)
1724        __insert_multi(_NodeTypes::__get_value(*__first));
1725}
1726
1727template <class _Tp, class _Hash, class _Equal, class _Alloc>
1728inline
1729typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1730__hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() _NOEXCEPT
1731{
1732    return iterator(__p1_.first().__next_, this);
1733}
1734
1735template <class _Tp, class _Hash, class _Equal, class _Alloc>
1736inline
1737typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1738__hash_table<_Tp, _Hash, _Equal, _Alloc>::end() _NOEXCEPT
1739{
1740    return iterator(nullptr, this);
1741}
1742
1743template <class _Tp, class _Hash, class _Equal, class _Alloc>
1744inline
1745typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
1746__hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() const _NOEXCEPT
1747{
1748    return const_iterator(__p1_.first().__next_, this);
1749}
1750
1751template <class _Tp, class _Hash, class _Equal, class _Alloc>
1752inline
1753typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
1754__hash_table<_Tp, _Hash, _Equal, _Alloc>::end() const _NOEXCEPT
1755{
1756    return const_iterator(nullptr, this);
1757}
1758
1759template <class _Tp, class _Hash, class _Equal, class _Alloc>
1760void
1761__hash_table<_Tp, _Hash, _Equal, _Alloc>::clear() _NOEXCEPT
1762{
1763    if (size() > 0)
1764    {
1765        __deallocate_node(__p1_.first().__next_);
1766        __p1_.first().__next_ = nullptr;
1767        size_type __bc = bucket_count();
1768        for (size_type __i = 0; __i < __bc; ++__i)
1769            __bucket_list_[__i] = nullptr;
1770        size() = 0;
1771    }
1772}
1773
1774
1775// Prepare the container for an insertion of the value __value with the hash
1776// __hash. This does a lookup into the container to see if __value is already
1777// present, and performs a rehash if necessary. Returns a pointer to the
1778// existing element if it exists, otherwise nullptr.
1779//
1780// Note that this function does forward exceptions if key_eq() throws, and never
1781// mutates __value or actually inserts into the map.
1782template <class _Tp, class _Hash, class _Equal, class _Alloc>
1783_LIBCPP_INLINE_VISIBILITY
1784typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1785__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique_prepare(
1786    size_t __hash, value_type& __value)
1787{
1788    size_type __bc = bucket_count();
1789
1790    if (__bc != 0)
1791    {
1792        size_t __chash = std::__constrain_hash(__hash, __bc);
1793        __next_pointer __ndptr = __bucket_list_[__chash];
1794        if (__ndptr != nullptr)
1795        {
1796            for (__ndptr = __ndptr->__next_; __ndptr != nullptr &&
1797                                             std::__constrain_hash(__ndptr->__hash(), __bc) == __chash;
1798                                                     __ndptr = __ndptr->__next_)
1799            {
1800                if (key_eq()(__ndptr->__upcast()->__value_, __value))
1801                    return __ndptr;
1802            }
1803        }
1804    }
1805    if (size()+1 > __bc * max_load_factor() || __bc == 0)
1806    {
1807        __rehash_unique(_VSTD::max<size_type>(2 * __bc + !std::__is_hash_power2(__bc),
1808                                     size_type(std::ceil(float(size() + 1) / max_load_factor()))));
1809    }
1810    return nullptr;
1811}
1812
1813// Insert the node __nd into the container by pushing it into the right bucket,
1814// and updating size(). Assumes that __nd->__hash is up-to-date, and that
1815// rehashing has already occurred and that no element with the same key exists
1816// in the map.
1817template <class _Tp, class _Hash, class _Equal, class _Alloc>
1818_LIBCPP_INLINE_VISIBILITY
1819void
1820__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique_perform(
1821    __node_pointer __nd) _NOEXCEPT
1822{
1823    size_type __bc = bucket_count();
1824    size_t __chash = std::__constrain_hash(__nd->__hash(), __bc);
1825    // insert_after __bucket_list_[__chash], or __first_node if bucket is null
1826    __next_pointer __pn = __bucket_list_[__chash];
1827    if (__pn == nullptr)
1828    {
1829        __pn =__p1_.first().__ptr();
1830        __nd->__next_ = __pn->__next_;
1831        __pn->__next_ = __nd->__ptr();
1832        // fix up __bucket_list_
1833        __bucket_list_[__chash] = __pn;
1834        if (__nd->__next_ != nullptr)
1835            __bucket_list_[std::__constrain_hash(__nd->__next_->__hash(), __bc)] = __nd->__ptr();
1836    }
1837    else
1838    {
1839        __nd->__next_ = __pn->__next_;
1840        __pn->__next_ = __nd->__ptr();
1841    }
1842    ++size();
1843}
1844
1845template <class _Tp, class _Hash, class _Equal, class _Alloc>
1846pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
1847__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique(__node_pointer __nd)
1848{
1849    __nd->__hash_ = hash_function()(__nd->__value_);
1850    __next_pointer __existing_node =
1851        __node_insert_unique_prepare(__nd->__hash(), __nd->__value_);
1852
1853    // Insert the node, unless it already exists in the container.
1854    bool __inserted = false;
1855    if (__existing_node == nullptr)
1856    {
1857        __node_insert_unique_perform(__nd);
1858        __existing_node = __nd->__ptr();
1859        __inserted = true;
1860    }
1861    return pair<iterator, bool>(iterator(__existing_node, this), __inserted);
1862}
1863
1864// Prepare the container for an insertion of the value __cp_val with the hash
1865// __cp_hash. This does a lookup into the container to see if __cp_value is
1866// already present, and performs a rehash if necessary. Returns a pointer to the
1867// last occurrence of __cp_val in the map.
1868//
1869// Note that this function does forward exceptions if key_eq() throws, and never
1870// mutates __value or actually inserts into the map.
1871template <class _Tp, class _Hash, class _Equal, class _Alloc>
1872typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1873__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi_prepare(
1874    size_t __cp_hash, value_type& __cp_val)
1875{
1876    size_type __bc = bucket_count();
1877    if (size()+1 > __bc * max_load_factor() || __bc == 0)
1878    {
1879        __rehash_multi(_VSTD::max<size_type>(2 * __bc + !std::__is_hash_power2(__bc),
1880                       size_type(std::ceil(float(size() + 1) / max_load_factor()))));
1881        __bc = bucket_count();
1882    }
1883    size_t __chash = std::__constrain_hash(__cp_hash, __bc);
1884    __next_pointer __pn = __bucket_list_[__chash];
1885    if (__pn != nullptr)
1886    {
1887        for (bool __found = false; __pn->__next_ != nullptr &&
1888                                   std::__constrain_hash(__pn->__next_->__hash(), __bc) == __chash;
1889                                                           __pn = __pn->__next_)
1890        {
1891            //      __found    key_eq()     action
1892            //      false       false       loop
1893            //      true        true        loop
1894            //      false       true        set __found to true
1895            //      true        false       break
1896            if (__found != (__pn->__next_->__hash() == __cp_hash &&
1897                            key_eq()(__pn->__next_->__upcast()->__value_, __cp_val)))
1898            {
1899                if (!__found)
1900                    __found = true;
1901                else
1902                    break;
1903            }
1904        }
1905    }
1906    return __pn;
1907}
1908
1909// Insert the node __cp into the container after __pn (which is the last node in
1910// the bucket that compares equal to __cp). Rehashing, and checking for
1911// uniqueness has already been performed (in __node_insert_multi_prepare), so
1912// all we need to do is update the bucket and size(). Assumes that __cp->__hash
1913// is up-to-date.
1914template <class _Tp, class _Hash, class _Equal, class _Alloc>
1915void
1916__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi_perform(
1917    __node_pointer __cp, __next_pointer __pn) _NOEXCEPT
1918{
1919    size_type __bc = bucket_count();
1920    size_t __chash = std::__constrain_hash(__cp->__hash_, __bc);
1921    if (__pn == nullptr)
1922    {
1923        __pn =__p1_.first().__ptr();
1924        __cp->__next_ = __pn->__next_;
1925        __pn->__next_ = __cp->__ptr();
1926        // fix up __bucket_list_
1927        __bucket_list_[__chash] = __pn;
1928        if (__cp->__next_ != nullptr)
1929            __bucket_list_[std::__constrain_hash(__cp->__next_->__hash(), __bc)]
1930                = __cp->__ptr();
1931    }
1932    else
1933    {
1934        __cp->__next_ = __pn->__next_;
1935        __pn->__next_ = __cp->__ptr();
1936        if (__cp->__next_ != nullptr)
1937        {
1938            size_t __nhash = std::__constrain_hash(__cp->__next_->__hash(), __bc);
1939            if (__nhash != __chash)
1940                __bucket_list_[__nhash] = __cp->__ptr();
1941        }
1942    }
1943    ++size();
1944}
1945
1946
1947template <class _Tp, class _Hash, class _Equal, class _Alloc>
1948typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1949__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(__node_pointer __cp)
1950{
1951    __cp->__hash_ = hash_function()(__cp->__value_);
1952    __next_pointer __pn = __node_insert_multi_prepare(__cp->__hash(), __cp->__value_);
1953    __node_insert_multi_perform(__cp, __pn);
1954
1955    return iterator(__cp->__ptr(), this);
1956}
1957
1958template <class _Tp, class _Hash, class _Equal, class _Alloc>
1959typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1960__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(
1961        const_iterator __p, __node_pointer __cp)
1962{
1963    _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
1964                         "unordered container::emplace_hint(const_iterator, args...) called with an iterator not"
1965                         " referring to this unordered container");
1966    if (__p != end() && key_eq()(*__p, __cp->__value_))
1967    {
1968        __next_pointer __np = __p.__node_;
1969        __cp->__hash_ = __np->__hash();
1970        size_type __bc = bucket_count();
1971        if (size()+1 > __bc * max_load_factor() || __bc == 0)
1972        {
1973            __rehash_multi(_VSTD::max<size_type>(2 * __bc + !std::__is_hash_power2(__bc),
1974                           size_type(std::ceil(float(size() + 1) / max_load_factor()))));
1975            __bc = bucket_count();
1976        }
1977        size_t __chash = std::__constrain_hash(__cp->__hash_, __bc);
1978        __next_pointer __pp = __bucket_list_[__chash];
1979        while (__pp->__next_ != __np)
1980            __pp = __pp->__next_;
1981        __cp->__next_ = __np;
1982        __pp->__next_ = static_cast<__next_pointer>(__cp);
1983        ++size();
1984        return iterator(static_cast<__next_pointer>(__cp), this);
1985    }
1986    return __node_insert_multi(__cp);
1987}
1988
1989
1990
1991template <class _Tp, class _Hash, class _Equal, class _Alloc>
1992template <class _Key, class ..._Args>
1993pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
1994__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const& __k, _Args&&... __args)
1995{
1996
1997    size_t __hash = hash_function()(__k);
1998    size_type __bc = bucket_count();
1999    bool __inserted = false;
2000    __next_pointer __nd;
2001    size_t __chash;
2002    if (__bc != 0)
2003    {
2004        __chash = std::__constrain_hash(__hash, __bc);
2005        __nd = __bucket_list_[__chash];
2006        if (__nd != nullptr)
2007        {
2008            for (__nd = __nd->__next_; __nd != nullptr &&
2009                (__nd->__hash() == __hash || std::__constrain_hash(__nd->__hash(), __bc) == __chash);
2010                                                           __nd = __nd->__next_)
2011            {
2012                if (key_eq()(__nd->__upcast()->__value_, __k))
2013                    goto __done;
2014            }
2015        }
2016    }
2017    {
2018        __node_holder __h = __construct_node_hash(__hash, _VSTD::forward<_Args>(__args)...);
2019        if (size()+1 > __bc * max_load_factor() || __bc == 0)
2020        {
2021            __rehash_unique(_VSTD::max<size_type>(2 * __bc + !std::__is_hash_power2(__bc),
2022                           size_type(std::ceil(float(size() + 1) / max_load_factor()))));
2023            __bc = bucket_count();
2024            __chash = std::__constrain_hash(__hash, __bc);
2025        }
2026        // insert_after __bucket_list_[__chash], or __first_node if bucket is null
2027        __next_pointer __pn = __bucket_list_[__chash];
2028        if (__pn == nullptr)
2029        {
2030            __pn = __p1_.first().__ptr();
2031            __h->__next_ = __pn->__next_;
2032            __pn->__next_ = __h.get()->__ptr();
2033            // fix up __bucket_list_
2034            __bucket_list_[__chash] = __pn;
2035            if (__h->__next_ != nullptr)
2036                __bucket_list_[std::__constrain_hash(__h->__next_->__hash(), __bc)]
2037                    = __h.get()->__ptr();
2038        }
2039        else
2040        {
2041            __h->__next_ = __pn->__next_;
2042            __pn->__next_ = static_cast<__next_pointer>(__h.get());
2043        }
2044        __nd = static_cast<__next_pointer>(__h.release());
2045        // increment size
2046        ++size();
2047        __inserted = true;
2048    }
2049__done:
2050    return pair<iterator, bool>(iterator(__nd, this), __inserted);
2051}
2052
2053template <class _Tp, class _Hash, class _Equal, class _Alloc>
2054template <class... _Args>
2055pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
2056__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_impl(_Args&&... __args)
2057{
2058    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
2059    pair<iterator, bool> __r = __node_insert_unique(__h.get());
2060    if (__r.second)
2061        __h.release();
2062    return __r;
2063}
2064
2065template <class _Tp, class _Hash, class _Equal, class _Alloc>
2066template <class... _Args>
2067typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2068__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_multi(_Args&&... __args)
2069{
2070    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
2071    iterator __r = __node_insert_multi(__h.get());
2072    __h.release();
2073    return __r;
2074}
2075
2076template <class _Tp, class _Hash, class _Equal, class _Alloc>
2077template <class... _Args>
2078typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2079__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_hint_multi(
2080        const_iterator __p, _Args&&... __args)
2081{
2082    _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
2083                         "unordered container::emplace_hint(const_iterator, args...) called with an iterator not"
2084                         " referring to this unordered container");
2085    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
2086    iterator __r = __node_insert_multi(__p, __h.get());
2087    __h.release();
2088    return __r;
2089}
2090
2091#if _LIBCPP_STD_VER > 14
2092template <class _Tp, class _Hash, class _Equal, class _Alloc>
2093template <class _NodeHandle, class _InsertReturnType>
2094_LIBCPP_INLINE_VISIBILITY
2095_InsertReturnType
2096__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_unique(
2097    _NodeHandle&& __nh)
2098{
2099    if (__nh.empty())
2100        return _InsertReturnType{end(), false, _NodeHandle()};
2101    pair<iterator, bool> __result = __node_insert_unique(__nh.__ptr_);
2102    if (__result.second)
2103        __nh.__release_ptr();
2104    return _InsertReturnType{__result.first, __result.second, _VSTD::move(__nh)};
2105}
2106
2107template <class _Tp, class _Hash, class _Equal, class _Alloc>
2108template <class _NodeHandle>
2109_LIBCPP_INLINE_VISIBILITY
2110typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2111__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_unique(
2112    const_iterator, _NodeHandle&& __nh)
2113{
2114    if (__nh.empty())
2115        return end();
2116    pair<iterator, bool> __result = __node_insert_unique(__nh.__ptr_);
2117    if (__result.second)
2118        __nh.__release_ptr();
2119    return __result.first;
2120}
2121
2122template <class _Tp, class _Hash, class _Equal, class _Alloc>
2123template <class _NodeHandle>
2124_LIBCPP_INLINE_VISIBILITY
2125_NodeHandle
2126__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_extract(
2127    key_type const& __key)
2128{
2129    iterator __i = find(__key);
2130    if (__i == end())
2131        return _NodeHandle();
2132    return __node_handle_extract<_NodeHandle>(__i);
2133}
2134
2135template <class _Tp, class _Hash, class _Equal, class _Alloc>
2136template <class _NodeHandle>
2137_LIBCPP_INLINE_VISIBILITY
2138_NodeHandle
2139__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_extract(
2140    const_iterator __p)
2141{
2142    allocator_type __alloc(__node_alloc());
2143    return _NodeHandle(remove(__p).release(), __alloc);
2144}
2145
2146template <class _Tp, class _Hash, class _Equal, class _Alloc>
2147template <class _Table>
2148_LIBCPP_INLINE_VISIBILITY
2149void
2150__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_merge_unique(
2151    _Table& __source)
2152{
2153    static_assert(is_same<__node, typename _Table::__node>::value, "");
2154
2155    for (typename _Table::iterator __it = __source.begin();
2156         __it != __source.end();)
2157    {
2158        __node_pointer __src_ptr = __it.__node_->__upcast();
2159        size_t __hash = hash_function()(__src_ptr->__value_);
2160        __next_pointer __existing_node =
2161            __node_insert_unique_prepare(__hash, __src_ptr->__value_);
2162        auto __prev_iter = __it++;
2163        if (__existing_node == nullptr)
2164        {
2165            (void)__source.remove(__prev_iter).release();
2166            __src_ptr->__hash_ = __hash;
2167            __node_insert_unique_perform(__src_ptr);
2168        }
2169    }
2170}
2171
2172template <class _Tp, class _Hash, class _Equal, class _Alloc>
2173template <class _NodeHandle>
2174_LIBCPP_INLINE_VISIBILITY
2175typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2176__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_multi(
2177    _NodeHandle&& __nh)
2178{
2179    if (__nh.empty())
2180        return end();
2181    iterator __result = __node_insert_multi(__nh.__ptr_);
2182    __nh.__release_ptr();
2183    return __result;
2184}
2185
2186template <class _Tp, class _Hash, class _Equal, class _Alloc>
2187template <class _NodeHandle>
2188_LIBCPP_INLINE_VISIBILITY
2189typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2190__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_multi(
2191    const_iterator __hint, _NodeHandle&& __nh)
2192{
2193    if (__nh.empty())
2194        return end();
2195    iterator __result = __node_insert_multi(__hint, __nh.__ptr_);
2196    __nh.__release_ptr();
2197    return __result;
2198}
2199
2200template <class _Tp, class _Hash, class _Equal, class _Alloc>
2201template <class _Table>
2202_LIBCPP_INLINE_VISIBILITY
2203void
2204__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_merge_multi(
2205    _Table& __source)
2206{
2207    static_assert(is_same<typename _Table::__node, __node>::value, "");
2208
2209    for (typename _Table::iterator __it = __source.begin();
2210         __it != __source.end();)
2211    {
2212        __node_pointer __src_ptr = __it.__node_->__upcast();
2213        size_t __src_hash = hash_function()(__src_ptr->__value_);
2214        __next_pointer __pn =
2215            __node_insert_multi_prepare(__src_hash, __src_ptr->__value_);
2216        (void)__source.remove(__it++).release();
2217        __src_ptr->__hash_ = __src_hash;
2218        __node_insert_multi_perform(__src_ptr, __pn);
2219    }
2220}
2221#endif // _LIBCPP_STD_VER > 14
2222
2223template <class _Tp, class _Hash, class _Equal, class _Alloc>
2224template <bool _UniqueKeys>
2225void
2226__hash_table<_Tp, _Hash, _Equal, _Alloc>::__rehash(size_type __n)
2227_LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
2228{
2229    if (__n == 1)
2230        __n = 2;
2231    else if (__n & (__n - 1))
2232        __n = std::__next_prime(__n);
2233    size_type __bc = bucket_count();
2234    if (__n > __bc)
2235        __do_rehash<_UniqueKeys>(__n);
2236    else if (__n < __bc)
2237    {
2238        __n = _VSTD::max<size_type>
2239              (
2240                  __n,
2241                  std::__is_hash_power2(__bc) ? std::__next_hash_pow2(size_t(std::ceil(float(size()) / max_load_factor()))) :
2242                                           std::__next_prime(size_t(std::ceil(float(size()) / max_load_factor())))
2243              );
2244        if (__n < __bc)
2245            __do_rehash<_UniqueKeys>(__n);
2246    }
2247}
2248
2249template <class _Tp, class _Hash, class _Equal, class _Alloc>
2250template <bool _UniqueKeys>
2251void
2252__hash_table<_Tp, _Hash, _Equal, _Alloc>::__do_rehash(size_type __nbc)
2253{
2254    std::__debug_db_invalidate_all(this);
2255    __pointer_allocator& __npa = __bucket_list_.get_deleter().__alloc();
2256    __bucket_list_.reset(__nbc > 0 ?
2257                      __pointer_alloc_traits::allocate(__npa, __nbc) : nullptr);
2258    __bucket_list_.get_deleter().size() = __nbc;
2259    if (__nbc > 0)
2260    {
2261        for (size_type __i = 0; __i < __nbc; ++__i)
2262            __bucket_list_[__i] = nullptr;
2263        __next_pointer __pp = __p1_.first().__ptr();
2264        __next_pointer __cp = __pp->__next_;
2265        if (__cp != nullptr)
2266        {
2267            size_type __chash = std::__constrain_hash(__cp->__hash(), __nbc);
2268            __bucket_list_[__chash] = __pp;
2269            size_type __phash = __chash;
2270            for (__pp = __cp, void(), __cp = __cp->__next_; __cp != nullptr;
2271                                                           __cp = __pp->__next_)
2272            {
2273                __chash = std::__constrain_hash(__cp->__hash(), __nbc);
2274                if (__chash == __phash)
2275                    __pp = __cp;
2276                else
2277                {
2278                    if (__bucket_list_[__chash] == nullptr)
2279                    {
2280                        __bucket_list_[__chash] = __pp;
2281                        __pp = __cp;
2282                        __phash = __chash;
2283                    }
2284                    else
2285                    {
2286                        __next_pointer __np = __cp;
2287                        if _LIBCPP_CONSTEXPR_SINCE_CXX17 (!_UniqueKeys)
2288                        {
2289                            for (; __np->__next_ != nullptr &&
2290                                   key_eq()(__cp->__upcast()->__value_,
2291                                            __np->__next_->__upcast()->__value_);
2292                                                               __np = __np->__next_)
2293                                ;
2294                        }
2295                        __pp->__next_ = __np->__next_;
2296                        __np->__next_ = __bucket_list_[__chash]->__next_;
2297                        __bucket_list_[__chash]->__next_ = __cp;
2298
2299                    }
2300                }
2301            }
2302        }
2303    }
2304}
2305
2306template <class _Tp, class _Hash, class _Equal, class _Alloc>
2307template <class _Key>
2308typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2309__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k)
2310{
2311    size_t __hash = hash_function()(__k);
2312    size_type __bc = bucket_count();
2313    if (__bc != 0)
2314    {
2315        size_t __chash = std::__constrain_hash(__hash, __bc);
2316        __next_pointer __nd = __bucket_list_[__chash];
2317        if (__nd != nullptr)
2318        {
2319            for (__nd = __nd->__next_; __nd != nullptr &&
2320                (__nd->__hash() == __hash
2321                  || std::__constrain_hash(__nd->__hash(), __bc) == __chash);
2322                                                           __nd = __nd->__next_)
2323            {
2324                if ((__nd->__hash() == __hash)
2325                    && key_eq()(__nd->__upcast()->__value_, __k))
2326                    return iterator(__nd, this);
2327            }
2328        }
2329    }
2330    return end();
2331}
2332
2333template <class _Tp, class _Hash, class _Equal, class _Alloc>
2334template <class _Key>
2335typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
2336__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k) const
2337{
2338    size_t __hash = hash_function()(__k);
2339    size_type __bc = bucket_count();
2340    if (__bc != 0)
2341    {
2342        size_t __chash = std::__constrain_hash(__hash, __bc);
2343        __next_pointer __nd = __bucket_list_[__chash];
2344        if (__nd != nullptr)
2345        {
2346            for (__nd = __nd->__next_; __nd != nullptr &&
2347                (__hash == __nd->__hash()
2348                    || std::__constrain_hash(__nd->__hash(), __bc) == __chash);
2349                                                           __nd = __nd->__next_)
2350            {
2351                if ((__nd->__hash() == __hash)
2352                    && key_eq()(__nd->__upcast()->__value_, __k))
2353                    return const_iterator(__nd, this);
2354            }
2355        }
2356
2357    }
2358    return end();
2359}
2360
2361template <class _Tp, class _Hash, class _Equal, class _Alloc>
2362template <class ..._Args>
2363typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2364__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node(_Args&& ...__args)
2365{
2366    static_assert(!__is_hash_value_type<_Args...>::value,
2367                  "Construct cannot be called with a hash value type");
2368    __node_allocator& __na = __node_alloc();
2369    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2370    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), _VSTD::forward<_Args>(__args)...);
2371    __h.get_deleter().__value_constructed = true;
2372    __h->__hash_ = hash_function()(__h->__value_);
2373    __h->__next_ = nullptr;
2374    return __h;
2375}
2376
2377template <class _Tp, class _Hash, class _Equal, class _Alloc>
2378template <class _First, class ..._Rest>
2379typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2380__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(
2381    size_t __hash, _First&& __f, _Rest&& ...__rest)
2382{
2383    static_assert(!__is_hash_value_type<_First, _Rest...>::value,
2384                  "Construct cannot be called with a hash value type");
2385    __node_allocator& __na = __node_alloc();
2386    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2387    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_),
2388                             _VSTD::forward<_First>(__f),
2389                             _VSTD::forward<_Rest>(__rest)...);
2390    __h.get_deleter().__value_constructed = true;
2391    __h->__hash_ = __hash;
2392    __h->__next_ = nullptr;
2393    return __h;
2394}
2395
2396template <class _Tp, class _Hash, class _Equal, class _Alloc>
2397typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2398__hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __p)
2399{
2400    __next_pointer __np = __p.__node_;
2401    _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__p)) == this,
2402                         "unordered container erase(iterator) called with an iterator not"
2403                         " referring to this container");
2404    _LIBCPP_ASSERT(__p != end(),
2405                   "unordered container erase(iterator) called with a non-dereferenceable iterator");
2406    iterator __r(__np, this);
2407    ++__r;
2408    remove(__p);
2409    return __r;
2410}
2411
2412template <class _Tp, class _Hash, class _Equal, class _Alloc>
2413typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2414__hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __first,
2415                                                const_iterator __last)
2416{
2417    _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__first)) == this,
2418                         "unordered container::erase(iterator, iterator) called with an iterator not"
2419                         " referring to this container");
2420    _LIBCPP_DEBUG_ASSERT(__get_const_db()->__find_c_from_i(_VSTD::addressof(__last)) == this,
2421                         "unordered container::erase(iterator, iterator) called with an iterator not"
2422                         " referring to this container");
2423    for (const_iterator __p = __first; __first != __last; __p = __first)
2424    {
2425        ++__first;
2426        erase(__p);
2427    }
2428    __next_pointer __np = __last.__node_;
2429    return iterator (__np, this);
2430}
2431
2432template <class _Tp, class _Hash, class _Equal, class _Alloc>
2433template <class _Key>
2434typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2435__hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_unique(const _Key& __k)
2436{
2437    iterator __i = find(__k);
2438    if (__i == end())
2439        return 0;
2440    erase(__i);
2441    return 1;
2442}
2443
2444template <class _Tp, class _Hash, class _Equal, class _Alloc>
2445template <class _Key>
2446typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2447__hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_multi(const _Key& __k)
2448{
2449    size_type __r = 0;
2450    iterator __i = find(__k);
2451    if (__i != end())
2452    {
2453        iterator __e = end();
2454        do
2455        {
2456            erase(__i++);
2457            ++__r;
2458        } while (__i != __e && key_eq()(*__i, __k));
2459    }
2460    return __r;
2461}
2462
2463template <class _Tp, class _Hash, class _Equal, class _Alloc>
2464typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2465__hash_table<_Tp, _Hash, _Equal, _Alloc>::remove(const_iterator __p) _NOEXCEPT
2466{
2467    // current node
2468    __next_pointer __cn = __p.__node_;
2469    size_type __bc = bucket_count();
2470    size_t __chash = std::__constrain_hash(__cn->__hash(), __bc);
2471    // find previous node
2472    __next_pointer __pn = __bucket_list_[__chash];
2473    for (; __pn->__next_ != __cn; __pn = __pn->__next_)
2474        ;
2475    // Fix up __bucket_list_
2476        // if __pn is not in same bucket (before begin is not in same bucket) &&
2477        //    if __cn->__next_ is not in same bucket (nullptr is not in same bucket)
2478    if (__pn == __p1_.first().__ptr()
2479            || std::__constrain_hash(__pn->__hash(), __bc) != __chash)
2480    {
2481        if (__cn->__next_ == nullptr
2482            || std::__constrain_hash(__cn->__next_->__hash(), __bc) != __chash)
2483            __bucket_list_[__chash] = nullptr;
2484    }
2485        // if __cn->__next_ is not in same bucket (nullptr is in same bucket)
2486    if (__cn->__next_ != nullptr)
2487    {
2488        size_t __nhash = std::__constrain_hash(__cn->__next_->__hash(), __bc);
2489        if (__nhash != __chash)
2490            __bucket_list_[__nhash] = __pn;
2491    }
2492    // remove __cn
2493    __pn->__next_ = __cn->__next_;
2494    __cn->__next_ = nullptr;
2495    --size();
2496#ifdef _LIBCPP_ENABLE_DEBUG_MODE
2497    __c_node* __c = __get_db()->__find_c_and_lock(this);
2498    for (__i_node** __dp = __c->end_; __dp != __c->beg_; )
2499    {
2500        --__dp;
2501        iterator* __i = static_cast<iterator*>((*__dp)->__i_);
2502        if (__i->__node_ == __cn)
2503        {
2504            (*__dp)->__c_ = nullptr;
2505            if (--__c->end_ != __dp)
2506                _VSTD::memmove(__dp, __dp+1, (__c->end_ - __dp)*sizeof(__i_node*));
2507        }
2508    }
2509    __get_db()->unlock();
2510#endif
2511    return __node_holder(__cn->__upcast(), _Dp(__node_alloc(), true));
2512}
2513
2514template <class _Tp, class _Hash, class _Equal, class _Alloc>
2515template <class _Key>
2516inline
2517typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2518__hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_unique(const _Key& __k) const
2519{
2520    return static_cast<size_type>(find(__k) != end());
2521}
2522
2523template <class _Tp, class _Hash, class _Equal, class _Alloc>
2524template <class _Key>
2525typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2526__hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_multi(const _Key& __k) const
2527{
2528    size_type __r = 0;
2529    const_iterator __i = find(__k);
2530    if (__i != end())
2531    {
2532        const_iterator __e = end();
2533        do
2534        {
2535            ++__i;
2536            ++__r;
2537        } while (__i != __e && key_eq()(*__i, __k));
2538    }
2539    return __r;
2540}
2541
2542template <class _Tp, class _Hash, class _Equal, class _Alloc>
2543template <class _Key>
2544pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
2545     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
2546__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(
2547        const _Key& __k)
2548{
2549    iterator __i = find(__k);
2550    iterator __j = __i;
2551    if (__i != end())
2552        ++__j;
2553    return pair<iterator, iterator>(__i, __j);
2554}
2555
2556template <class _Tp, class _Hash, class _Equal, class _Alloc>
2557template <class _Key>
2558pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
2559     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
2560__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(
2561        const _Key& __k) const
2562{
2563    const_iterator __i = find(__k);
2564    const_iterator __j = __i;
2565    if (__i != end())
2566        ++__j;
2567    return pair<const_iterator, const_iterator>(__i, __j);
2568}
2569
2570template <class _Tp, class _Hash, class _Equal, class _Alloc>
2571template <class _Key>
2572pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
2573     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
2574__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(
2575        const _Key& __k)
2576{
2577    iterator __i = find(__k);
2578    iterator __j = __i;
2579    if (__i != end())
2580    {
2581        iterator __e = end();
2582        do
2583        {
2584            ++__j;
2585        } while (__j != __e && key_eq()(*__j, __k));
2586    }
2587    return pair<iterator, iterator>(__i, __j);
2588}
2589
2590template <class _Tp, class _Hash, class _Equal, class _Alloc>
2591template <class _Key>
2592pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
2593     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
2594__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(
2595        const _Key& __k) const
2596{
2597    const_iterator __i = find(__k);
2598    const_iterator __j = __i;
2599    if (__i != end())
2600    {
2601        const_iterator __e = end();
2602        do
2603        {
2604            ++__j;
2605        } while (__j != __e && key_eq()(*__j, __k));
2606    }
2607    return pair<const_iterator, const_iterator>(__i, __j);
2608}
2609
2610template <class _Tp, class _Hash, class _Equal, class _Alloc>
2611void
2612__hash_table<_Tp, _Hash, _Equal, _Alloc>::swap(__hash_table& __u)
2613#if _LIBCPP_STD_VER <= 11
2614    _NOEXCEPT_(
2615        __is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value
2616        && (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value
2617              || __is_nothrow_swappable<__pointer_allocator>::value)
2618        && (!__node_traits::propagate_on_container_swap::value
2619              || __is_nothrow_swappable<__node_allocator>::value)
2620            )
2621#else
2622  _NOEXCEPT_(__is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value)
2623#endif
2624{
2625    _LIBCPP_ASSERT(__node_traits::propagate_on_container_swap::value ||
2626                   this->__node_alloc() == __u.__node_alloc(),
2627                   "list::swap: Either propagate_on_container_swap must be true"
2628                   " or the allocators must compare equal");
2629    {
2630    __node_pointer_pointer __npp = __bucket_list_.release();
2631    __bucket_list_.reset(__u.__bucket_list_.release());
2632    __u.__bucket_list_.reset(__npp);
2633    }
2634    _VSTD::swap(__bucket_list_.get_deleter().size(), __u.__bucket_list_.get_deleter().size());
2635    _VSTD::__swap_allocator(__bucket_list_.get_deleter().__alloc(),
2636             __u.__bucket_list_.get_deleter().__alloc());
2637    _VSTD::__swap_allocator(__node_alloc(), __u.__node_alloc());
2638    _VSTD::swap(__p1_.first().__next_, __u.__p1_.first().__next_);
2639    __p2_.swap(__u.__p2_);
2640    __p3_.swap(__u.__p3_);
2641    if (size() > 0)
2642        __bucket_list_[std::__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
2643            __p1_.first().__ptr();
2644    if (__u.size() > 0)
2645        __u.__bucket_list_[std::__constrain_hash(__u.__p1_.first().__next_->__hash(), __u.bucket_count())] =
2646            __u.__p1_.first().__ptr();
2647    std::__debug_db_swap(this, std::addressof(__u));
2648}
2649
2650template <class _Tp, class _Hash, class _Equal, class _Alloc>
2651typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2652__hash_table<_Tp, _Hash, _Equal, _Alloc>::bucket_size(size_type __n) const
2653{
2654    _LIBCPP_ASSERT(__n < bucket_count(),
2655        "unordered container::bucket_size(n) called with n >= bucket_count()");
2656    __next_pointer __np = __bucket_list_[__n];
2657    size_type __bc = bucket_count();
2658    size_type __r = 0;
2659    if (__np != nullptr)
2660    {
2661        for (__np = __np->__next_; __np != nullptr &&
2662                                   std::__constrain_hash(__np->__hash(), __bc) == __n;
2663                                                         __np = __np->__next_, (void) ++__r)
2664            ;
2665    }
2666    return __r;
2667}
2668
2669template <class _Tp, class _Hash, class _Equal, class _Alloc>
2670inline _LIBCPP_INLINE_VISIBILITY
2671void
2672swap(__hash_table<_Tp, _Hash, _Equal, _Alloc>& __x,
2673     __hash_table<_Tp, _Hash, _Equal, _Alloc>& __y)
2674    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
2675{
2676    __x.swap(__y);
2677}
2678
2679#ifdef _LIBCPP_ENABLE_DEBUG_MODE
2680
2681template <class _Tp, class _Hash, class _Equal, class _Alloc>
2682bool
2683__hash_table<_Tp, _Hash, _Equal, _Alloc>::__dereferenceable(const const_iterator* __i) const
2684{
2685    return __i->__node_ != nullptr;
2686}
2687
2688template <class _Tp, class _Hash, class _Equal, class _Alloc>
2689bool
2690__hash_table<_Tp, _Hash, _Equal, _Alloc>::__decrementable(const const_iterator*) const
2691{
2692    return false;
2693}
2694
2695template <class _Tp, class _Hash, class _Equal, class _Alloc>
2696bool
2697__hash_table<_Tp, _Hash, _Equal, _Alloc>::__addable(const const_iterator*, ptrdiff_t) const
2698{
2699    return false;
2700}
2701
2702template <class _Tp, class _Hash, class _Equal, class _Alloc>
2703bool
2704__hash_table<_Tp, _Hash, _Equal, _Alloc>::__subscriptable(const const_iterator*, ptrdiff_t) const
2705{
2706    return false;
2707}
2708
2709#endif // _LIBCPP_ENABLE_DEBUG_MODE
2710
2711_LIBCPP_END_NAMESPACE_STD
2712
2713_LIBCPP_POP_MACROS
2714
2715#endif // _LIBCPP___HASH_TABLE
2716