• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP__HASH_TABLE
12#define _LIBCPP__HASH_TABLE
13
14#include <__config>
15#include <initializer_list>
16#include <memory>
17#include <iterator>
18#include <algorithm>
19#include <cmath>
20#include <utility>
21#include <type_traits>
22
23#include <__debug>
24
25#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26#pragma GCC system_header
27#endif
28
29_LIBCPP_PUSH_MACROS
30#include <__undef_macros>
31
32
33_LIBCPP_BEGIN_NAMESPACE_STD
34
35template <class _Key, class _Tp>
36struct __hash_value_type;
37
38#ifndef _LIBCPP_CXX03_LANG
39template <class _Tp>
40struct __is_hash_value_type_imp : false_type {};
41
42template <class _Key, class _Value>
43struct __is_hash_value_type_imp<__hash_value_type<_Key, _Value>> : true_type {};
44
45template <class ..._Args>
46struct __is_hash_value_type : false_type {};
47
48template <class _One>
49struct __is_hash_value_type<_One> : __is_hash_value_type_imp<typename __uncvref<_One>::type> {};
50#endif
51
52_LIBCPP_FUNC_VIS
53size_t __next_prime(size_t __n);
54
55template <class _NodePtr>
56struct __hash_node_base
57{
58    typedef typename pointer_traits<_NodePtr>::element_type __node_type;
59    typedef __hash_node_base __first_node;
60    typedef typename __rebind_pointer<_NodePtr, __first_node>::type __node_base_pointer;
61    typedef _NodePtr __node_pointer;
62
63#if defined(_LIBCPP_ABI_FIX_UNORDERED_NODE_POINTER_UB)
64  typedef __node_base_pointer __next_pointer;
65#else
66  typedef typename conditional<
67      is_pointer<__node_pointer>::value,
68      __node_base_pointer,
69      __node_pointer>::type   __next_pointer;
70#endif
71
72    __next_pointer    __next_;
73
74    _LIBCPP_INLINE_VISIBILITY
75    __next_pointer __ptr() _NOEXCEPT {
76        return static_cast<__next_pointer>(
77            pointer_traits<__node_base_pointer>::pointer_to(*this));
78    }
79
80    _LIBCPP_INLINE_VISIBILITY
81    __node_pointer __upcast() _NOEXCEPT {
82        return static_cast<__node_pointer>(
83            pointer_traits<__node_base_pointer>::pointer_to(*this));
84    }
85
86    _LIBCPP_INLINE_VISIBILITY
87    size_t __hash() const _NOEXCEPT {
88        return static_cast<__node_type const&>(*this).__hash_;
89    }
90
91    _LIBCPP_INLINE_VISIBILITY __hash_node_base() _NOEXCEPT : __next_(nullptr) {}
92};
93
94template <class _Tp, class _VoidPtr>
95struct __hash_node
96    : public __hash_node_base
97             <
98                 typename __rebind_pointer<_VoidPtr, __hash_node<_Tp, _VoidPtr> >::type
99             >
100{
101    typedef _Tp __node_value_type;
102
103    size_t            __hash_;
104    __node_value_type __value_;
105};
106
107inline _LIBCPP_INLINE_VISIBILITY
108bool
109__is_hash_power2(size_t __bc)
110{
111    return __bc > 2 && !(__bc & (__bc - 1));
112}
113
114inline _LIBCPP_INLINE_VISIBILITY
115size_t
116__constrain_hash(size_t __h, size_t __bc)
117{
118    return !(__bc & (__bc - 1)) ? __h & (__bc - 1) :
119        (__h < __bc ? __h : __h % __bc);
120}
121
122inline _LIBCPP_INLINE_VISIBILITY
123size_t
124__next_hash_pow2(size_t __n)
125{
126    return __n < 2 ? __n : (size_t(1) << (std::numeric_limits<size_t>::digits - __clz(__n-1)));
127}
128
129
130template <class _Tp, class _Hash, class _Equal, class _Alloc> class __hash_table;
131
132template <class _NodePtr>      class _LIBCPP_TEMPLATE_VIS __hash_iterator;
133template <class _ConstNodePtr> class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
134template <class _NodePtr>      class _LIBCPP_TEMPLATE_VIS __hash_local_iterator;
135template <class _ConstNodePtr> class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
136template <class _HashIterator> class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
137template <class _HashIterator> class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
138
139template <class _Tp>
140struct __hash_key_value_types {
141  static_assert(!is_reference<_Tp>::value && !is_const<_Tp>::value, "");
142  typedef _Tp key_type;
143  typedef _Tp __node_value_type;
144  typedef _Tp __container_value_type;
145  static const bool __is_map = false;
146
147  _LIBCPP_INLINE_VISIBILITY
148  static key_type const& __get_key(_Tp const& __v) {
149    return __v;
150  }
151  _LIBCPP_INLINE_VISIBILITY
152  static __container_value_type const& __get_value(__node_value_type const& __v) {
153    return __v;
154  }
155  _LIBCPP_INLINE_VISIBILITY
156  static __container_value_type* __get_ptr(__node_value_type& __n) {
157    return _VSTD::addressof(__n);
158  }
159#ifndef _LIBCPP_CXX03_LANG
160  _LIBCPP_INLINE_VISIBILITY
161  static __container_value_type&& __move(__node_value_type& __v) {
162    return _VSTD::move(__v);
163  }
164#endif
165};
166
167template <class _Key, class _Tp>
168struct __hash_key_value_types<__hash_value_type<_Key, _Tp> > {
169  typedef _Key                                         key_type;
170  typedef _Tp                                          mapped_type;
171  typedef __hash_value_type<_Key, _Tp>                 __node_value_type;
172  typedef pair<const _Key, _Tp>                        __container_value_type;
173  typedef __container_value_type                       __map_value_type;
174  static const bool __is_map = true;
175
176  _LIBCPP_INLINE_VISIBILITY
177  static key_type const& __get_key(__container_value_type const& __v) {
178    return __v.first;
179  }
180
181  template <class _Up>
182  _LIBCPP_INLINE_VISIBILITY
183  static typename enable_if<__is_same_uncvref<_Up, __node_value_type>::value,
184      __container_value_type const&>::type
185  __get_value(_Up& __t) {
186    return __t.__get_value();
187  }
188
189  template <class _Up>
190  _LIBCPP_INLINE_VISIBILITY
191  static typename enable_if<__is_same_uncvref<_Up, __container_value_type>::value,
192      __container_value_type const&>::type
193  __get_value(_Up& __t) {
194    return __t;
195  }
196
197  _LIBCPP_INLINE_VISIBILITY
198  static __container_value_type* __get_ptr(__node_value_type& __n) {
199    return _VSTD::addressof(__n.__get_value());
200  }
201#ifndef _LIBCPP_CXX03_LANG
202  _LIBCPP_INLINE_VISIBILITY
203  static pair<key_type&&, mapped_type&&> __move(__node_value_type& __v) {
204    return __v.__move();
205  }
206#endif
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 typename __rebind_pointer<_AllocPtr, _Mv>::type
218                                                       __map_value_type_pointer;
219  typedef typename __rebind_pointer<_AllocPtr, const _Mv>::type
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 typename __rebind_pointer<_NodePtr, void>::type       __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 typename __rebind_pointer<_NodePtr, __node_base_type>::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 typename __rebind_pointer<_VoidPtr, __node_value_type>::type
250                                                      __node_value_type_pointer;
251  typedef typename __rebind_pointer<_VoidPtr, const __node_value_type>::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<typename __rebind_pointer<_VoidPtr, __node_type>::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 typename __rebind_pointer<_VoidPtr, _NodeTp>::type _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        _LIBCPP_DEBUG_MODE(__get_db()->__insert_i(this));
300    }
301
302#if _LIBCPP_DEBUG_LEVEL >= 2
303    _LIBCPP_INLINE_VISIBILITY
304    __hash_iterator(const __hash_iterator& __i)
305        : __node_(__i.__node_)
306    {
307        __get_db()->__iterator_copy(this, &__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 != &__i)
320        {
321            __get_db()->__iterator_copy(this, &__i);
322            __node_ = __i.__node_;
323        }
324        return *this;
325    }
326#endif  // _LIBCPP_DEBUG_LEVEL >= 2
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 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#if _LIBCPP_DEBUG_LEVEL >= 2
369    _LIBCPP_INLINE_VISIBILITY
370    __hash_iterator(__next_pointer __node, const void* __c) _NOEXCEPT
371        : __node_(__node)
372        {
373            __get_db()->__insert_ic(this, __c);
374        }
375#else
376    _LIBCPP_INLINE_VISIBILITY
377    __hash_iterator(__next_pointer __node) _NOEXCEPT
378        : __node_(__node)
379        {}
380#endif
381    template <class, class, class, class> friend class __hash_table;
382    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
383    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
384    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
385    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
386};
387
388template <class _NodePtr>
389class _LIBCPP_TEMPLATE_VIS __hash_const_iterator
390{
391    static_assert(!is_const<typename pointer_traits<_NodePtr>::element_type>::value, "");
392    typedef __hash_node_types<_NodePtr> _NodeTypes;
393    typedef _NodePtr                            __node_pointer;
394    typedef typename _NodeTypes::__next_pointer __next_pointer;
395
396    __next_pointer __node_;
397
398public:
399    typedef __hash_iterator<_NodePtr> __non_const_iterator;
400
401    typedef forward_iterator_tag                                 iterator_category;
402    typedef typename _NodeTypes::__node_value_type               value_type;
403    typedef typename _NodeTypes::difference_type                 difference_type;
404    typedef const value_type&                                    reference;
405    typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
406
407
408    _LIBCPP_INLINE_VISIBILITY __hash_const_iterator() _NOEXCEPT : __node_(nullptr) {
409        _LIBCPP_DEBUG_MODE(__get_db()->__insert_i(this));
410    }
411
412    _LIBCPP_INLINE_VISIBILITY
413    __hash_const_iterator(const __non_const_iterator& __x) _NOEXCEPT
414        : __node_(__x.__node_)
415    {
416        _LIBCPP_DEBUG_MODE(__get_db()->__iterator_copy(this, &__x));
417    }
418
419#if _LIBCPP_DEBUG_LEVEL >= 2
420    _LIBCPP_INLINE_VISIBILITY
421    __hash_const_iterator(const __hash_const_iterator& __i)
422        : __node_(__i.__node_)
423    {
424        __get_db()->__iterator_copy(this, &__i);
425    }
426
427    _LIBCPP_INLINE_VISIBILITY
428    ~__hash_const_iterator()
429    {
430        __get_db()->__erase_i(this);
431    }
432
433    _LIBCPP_INLINE_VISIBILITY
434    __hash_const_iterator& operator=(const __hash_const_iterator& __i)
435    {
436        if (this != &__i)
437        {
438            __get_db()->__iterator_copy(this, &__i);
439            __node_ = __i.__node_;
440        }
441        return *this;
442    }
443#endif  // _LIBCPP_DEBUG_LEVEL >= 2
444
445    _LIBCPP_INLINE_VISIBILITY
446    reference operator*() const {
447        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
448                           "Attempted to dereference a non-dereferenceable unordered container const_iterator");
449        return __node_->__upcast()->__value_;
450    }
451    _LIBCPP_INLINE_VISIBILITY
452    pointer operator->() const {
453        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
454                           "Attempted to dereference a non-dereferenceable unordered container const_iterator");
455        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
456    }
457
458    _LIBCPP_INLINE_VISIBILITY
459    __hash_const_iterator& operator++() {
460        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
461                             "Attempted to increment non-incrementable unordered container const_iterator");
462        __node_ = __node_->__next_;
463        return *this;
464    }
465
466    _LIBCPP_INLINE_VISIBILITY
467    __hash_const_iterator operator++(int)
468    {
469        __hash_const_iterator __t(*this);
470        ++(*this);
471        return __t;
472    }
473
474    friend _LIBCPP_INLINE_VISIBILITY
475    bool operator==(const __hash_const_iterator& __x, const __hash_const_iterator& __y)
476    {
477        return __x.__node_ == __y.__node_;
478    }
479    friend _LIBCPP_INLINE_VISIBILITY
480    bool operator!=(const __hash_const_iterator& __x, const __hash_const_iterator& __y)
481        {return !(__x == __y);}
482
483private:
484#if _LIBCPP_DEBUG_LEVEL >= 2
485    _LIBCPP_INLINE_VISIBILITY
486    __hash_const_iterator(__next_pointer __node, const void* __c) _NOEXCEPT
487        : __node_(__node)
488        {
489            __get_db()->__insert_ic(this, __c);
490        }
491#else
492    _LIBCPP_INLINE_VISIBILITY
493    __hash_const_iterator(__next_pointer __node) _NOEXCEPT
494        : __node_(__node)
495        {}
496#endif
497    template <class, class, class, class> friend class __hash_table;
498    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
499    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
500    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
501};
502
503template <class _NodePtr>
504class _LIBCPP_TEMPLATE_VIS __hash_local_iterator
505{
506    typedef __hash_node_types<_NodePtr> _NodeTypes;
507    typedef _NodePtr                            __node_pointer;
508    typedef typename _NodeTypes::__next_pointer __next_pointer;
509
510    __next_pointer         __node_;
511    size_t                 __bucket_;
512    size_t                 __bucket_count_;
513
514public:
515    typedef forward_iterator_tag                                iterator_category;
516    typedef typename _NodeTypes::__node_value_type              value_type;
517    typedef typename _NodeTypes::difference_type                difference_type;
518    typedef value_type&                                         reference;
519    typedef typename _NodeTypes::__node_value_type_pointer      pointer;
520
521    _LIBCPP_INLINE_VISIBILITY __hash_local_iterator() _NOEXCEPT : __node_(nullptr) {
522        _LIBCPP_DEBUG_MODE(__get_db()->__insert_i(this));
523    }
524
525#if _LIBCPP_DEBUG_LEVEL >= 2
526    _LIBCPP_INLINE_VISIBILITY
527    __hash_local_iterator(const __hash_local_iterator& __i)
528        : __node_(__i.__node_),
529          __bucket_(__i.__bucket_),
530          __bucket_count_(__i.__bucket_count_)
531    {
532        __get_db()->__iterator_copy(this, &__i);
533    }
534
535    _LIBCPP_INLINE_VISIBILITY
536    ~__hash_local_iterator()
537    {
538        __get_db()->__erase_i(this);
539    }
540
541    _LIBCPP_INLINE_VISIBILITY
542    __hash_local_iterator& operator=(const __hash_local_iterator& __i)
543    {
544        if (this != &__i)
545        {
546            __get_db()->__iterator_copy(this, &__i);
547            __node_ = __i.__node_;
548            __bucket_ = __i.__bucket_;
549            __bucket_count_ = __i.__bucket_count_;
550        }
551        return *this;
552    }
553#endif  // _LIBCPP_DEBUG_LEVEL >= 2
554
555    _LIBCPP_INLINE_VISIBILITY
556    reference operator*() const {
557        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
558                           "Attempted to dereference a non-dereferenceable unordered container local_iterator");
559        return __node_->__upcast()->__value_;
560    }
561
562    _LIBCPP_INLINE_VISIBILITY
563    pointer operator->() const {
564        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
565                             "Attempted to dereference a non-dereferenceable unordered container local_iterator");
566        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
567    }
568
569    _LIBCPP_INLINE_VISIBILITY
570    __hash_local_iterator& operator++() {
571        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
572                       "Attempted to increment non-incrementable unordered container local_iterator");
573        __node_ = __node_->__next_;
574        if (__node_ != nullptr && __constrain_hash(__node_->__hash(), __bucket_count_) != __bucket_)
575            __node_ = nullptr;
576        return *this;
577    }
578
579    _LIBCPP_INLINE_VISIBILITY
580    __hash_local_iterator operator++(int)
581    {
582        __hash_local_iterator __t(*this);
583        ++(*this);
584        return __t;
585    }
586
587    friend _LIBCPP_INLINE_VISIBILITY
588    bool operator==(const __hash_local_iterator& __x, const __hash_local_iterator& __y)
589    {
590        return __x.__node_ == __y.__node_;
591    }
592    friend _LIBCPP_INLINE_VISIBILITY
593    bool operator!=(const __hash_local_iterator& __x, const __hash_local_iterator& __y)
594        {return !(__x == __y);}
595
596private:
597#if _LIBCPP_DEBUG_LEVEL >= 2
598    _LIBCPP_INLINE_VISIBILITY
599    __hash_local_iterator(__next_pointer __node, size_t __bucket,
600                          size_t __bucket_count, const void* __c) _NOEXCEPT
601        : __node_(__node),
602          __bucket_(__bucket),
603          __bucket_count_(__bucket_count)
604        {
605            __get_db()->__insert_ic(this, __c);
606            if (__node_ != nullptr)
607                __node_ = __node_->__next_;
608        }
609#else
610    _LIBCPP_INLINE_VISIBILITY
611    __hash_local_iterator(__next_pointer __node, size_t __bucket,
612                          size_t __bucket_count) _NOEXCEPT
613        : __node_(__node),
614          __bucket_(__bucket),
615          __bucket_count_(__bucket_count)
616        {
617            if (__node_ != nullptr)
618                __node_ = __node_->__next_;
619        }
620#endif
621    template <class, class, class, class> friend class __hash_table;
622    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
623    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
624};
625
626template <class _ConstNodePtr>
627class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator
628{
629    typedef __hash_node_types<_ConstNodePtr> _NodeTypes;
630    typedef _ConstNodePtr                       __node_pointer;
631    typedef typename _NodeTypes::__next_pointer __next_pointer;
632
633    __next_pointer         __node_;
634    size_t                 __bucket_;
635    size_t                 __bucket_count_;
636
637    typedef pointer_traits<__node_pointer>          __pointer_traits;
638    typedef typename __pointer_traits::element_type __node;
639    typedef typename remove_const<__node>::type     __non_const_node;
640    typedef typename __rebind_pointer<__node_pointer, __non_const_node>::type
641        __non_const_node_pointer;
642public:
643    typedef __hash_local_iterator<__non_const_node_pointer>
644                                                    __non_const_iterator;
645
646    typedef forward_iterator_tag                                 iterator_category;
647    typedef typename _NodeTypes::__node_value_type               value_type;
648    typedef typename _NodeTypes::difference_type                 difference_type;
649    typedef const value_type&                                    reference;
650    typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
651
652
653    _LIBCPP_INLINE_VISIBILITY __hash_const_local_iterator() _NOEXCEPT : __node_(nullptr) {
654        _LIBCPP_DEBUG_MODE(__get_db()->__insert_i(this));
655    }
656
657    _LIBCPP_INLINE_VISIBILITY
658    __hash_const_local_iterator(const __non_const_iterator& __x) _NOEXCEPT
659        : __node_(__x.__node_),
660          __bucket_(__x.__bucket_),
661          __bucket_count_(__x.__bucket_count_)
662    {
663        _LIBCPP_DEBUG_MODE(__get_db()->__iterator_copy(this, &__x));
664    }
665
666#if _LIBCPP_DEBUG_LEVEL >= 2
667    _LIBCPP_INLINE_VISIBILITY
668    __hash_const_local_iterator(const __hash_const_local_iterator& __i)
669        : __node_(__i.__node_),
670          __bucket_(__i.__bucket_),
671          __bucket_count_(__i.__bucket_count_)
672    {
673        __get_db()->__iterator_copy(this, &__i);
674    }
675
676    _LIBCPP_INLINE_VISIBILITY
677    ~__hash_const_local_iterator()
678    {
679        __get_db()->__erase_i(this);
680    }
681
682    _LIBCPP_INLINE_VISIBILITY
683    __hash_const_local_iterator& operator=(const __hash_const_local_iterator& __i)
684    {
685        if (this != &__i)
686        {
687            __get_db()->__iterator_copy(this, &__i);
688            __node_ = __i.__node_;
689            __bucket_ = __i.__bucket_;
690            __bucket_count_ = __i.__bucket_count_;
691        }
692        return *this;
693    }
694#endif  // _LIBCPP_DEBUG_LEVEL >= 2
695
696    _LIBCPP_INLINE_VISIBILITY
697    reference operator*() const {
698        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
699                           "Attempted to dereference a non-dereferenceable unordered container const_local_iterator");
700        return __node_->__upcast()->__value_;
701    }
702
703    _LIBCPP_INLINE_VISIBILITY
704    pointer operator->() const {
705        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
706                           "Attempted to dereference a non-dereferenceable unordered container const_local_iterator");
707        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
708    }
709
710    _LIBCPP_INLINE_VISIBILITY
711    __hash_const_local_iterator& operator++() {
712        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
713                       "Attempted to increment non-incrementable unordered container const_local_iterator");
714        __node_ = __node_->__next_;
715        if (__node_ != nullptr && __constrain_hash(__node_->__hash(), __bucket_count_) != __bucket_)
716            __node_ = nullptr;
717        return *this;
718    }
719
720    _LIBCPP_INLINE_VISIBILITY
721    __hash_const_local_iterator operator++(int)
722    {
723        __hash_const_local_iterator __t(*this);
724        ++(*this);
725        return __t;
726    }
727
728    friend _LIBCPP_INLINE_VISIBILITY
729    bool operator==(const __hash_const_local_iterator& __x, const __hash_const_local_iterator& __y)
730    {
731        return __x.__node_ == __y.__node_;
732    }
733    friend _LIBCPP_INLINE_VISIBILITY
734    bool operator!=(const __hash_const_local_iterator& __x, const __hash_const_local_iterator& __y)
735        {return !(__x == __y);}
736
737private:
738#if _LIBCPP_DEBUG_LEVEL >= 2
739    _LIBCPP_INLINE_VISIBILITY
740    __hash_const_local_iterator(__next_pointer __node, size_t __bucket,
741                                size_t __bucket_count, const void* __c) _NOEXCEPT
742        : __node_(__node),
743          __bucket_(__bucket),
744          __bucket_count_(__bucket_count)
745        {
746            __get_db()->__insert_ic(this, __c);
747            if (__node_ != nullptr)
748                __node_ = __node_->__next_;
749        }
750#else
751    _LIBCPP_INLINE_VISIBILITY
752    __hash_const_local_iterator(__next_pointer __node, size_t __bucket,
753                                size_t __bucket_count) _NOEXCEPT
754        : __node_(__node),
755          __bucket_(__bucket),
756          __bucket_count_(__bucket_count)
757        {
758            if (__node_ != nullptr)
759                __node_ = __node_->__next_;
760        }
761#endif
762    template <class, class, class, class> friend class __hash_table;
763    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
764};
765
766template <class _Alloc>
767class __bucket_list_deallocator
768{
769    typedef _Alloc                                          allocator_type;
770    typedef allocator_traits<allocator_type>                __alloc_traits;
771    typedef typename __alloc_traits::size_type              size_type;
772
773    __compressed_pair<size_type, allocator_type> __data_;
774public:
775    typedef typename __alloc_traits::pointer pointer;
776
777    _LIBCPP_INLINE_VISIBILITY
778    __bucket_list_deallocator()
779        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
780        : __data_(0) {}
781
782    _LIBCPP_INLINE_VISIBILITY
783    __bucket_list_deallocator(const allocator_type& __a, size_type __size)
784        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
785        : __data_(__size, __a) {}
786
787#ifndef _LIBCPP_CXX03_LANG
788    _LIBCPP_INLINE_VISIBILITY
789    __bucket_list_deallocator(__bucket_list_deallocator&& __x)
790        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
791        : __data_(_VSTD::move(__x.__data_))
792    {
793        __x.size() = 0;
794    }
795#endif
796
797    _LIBCPP_INLINE_VISIBILITY
798    size_type& size() _NOEXCEPT {return __data_.first();}
799    _LIBCPP_INLINE_VISIBILITY
800    size_type  size() const _NOEXCEPT {return __data_.first();}
801
802    _LIBCPP_INLINE_VISIBILITY
803    allocator_type& __alloc() _NOEXCEPT {return __data_.second();}
804    _LIBCPP_INLINE_VISIBILITY
805    const allocator_type& __alloc() const _NOEXCEPT {return __data_.second();}
806
807    _LIBCPP_INLINE_VISIBILITY
808    void operator()(pointer __p) _NOEXCEPT
809    {
810        __alloc_traits::deallocate(__alloc(), __p, size());
811    }
812};
813
814template <class _Alloc> class __hash_map_node_destructor;
815
816template <class _Alloc>
817class __hash_node_destructor
818{
819    typedef _Alloc                                          allocator_type;
820    typedef allocator_traits<allocator_type>                __alloc_traits;
821
822public:
823    typedef typename __alloc_traits::pointer                pointer;
824private:
825    typedef __hash_node_types<pointer> _NodeTypes;
826
827    allocator_type& __na_;
828
829    __hash_node_destructor& operator=(const __hash_node_destructor&);
830
831public:
832    bool __value_constructed;
833
834    _LIBCPP_INLINE_VISIBILITY
835    explicit __hash_node_destructor(allocator_type& __na,
836                                    bool __constructed = false) _NOEXCEPT
837        : __na_(__na),
838          __value_constructed(__constructed)
839        {}
840
841    _LIBCPP_INLINE_VISIBILITY
842    void operator()(pointer __p) _NOEXCEPT
843    {
844        if (__value_constructed)
845            __alloc_traits::destroy(__na_, _NodeTypes::__get_ptr(__p->__value_));
846        if (__p)
847            __alloc_traits::deallocate(__na_, __p, 1);
848    }
849
850    template <class> friend class __hash_map_node_destructor;
851};
852
853#if _LIBCPP_STD_VER > 14
854template <class _NodeType, class _Alloc>
855struct __generic_container_node_destructor;
856
857template <class _Tp, class _VoidPtr, class _Alloc>
858struct __generic_container_node_destructor<__hash_node<_Tp, _VoidPtr>, _Alloc>
859    : __hash_node_destructor<_Alloc>
860{
861    using __hash_node_destructor<_Alloc>::__hash_node_destructor;
862};
863#endif
864
865template <class _Key, class _Hash, class _Equal>
866struct __enforce_unordered_container_requirements {
867#ifndef _LIBCPP_CXX03_LANG
868    static_assert(__check_hash_requirements<_Key, _Hash>::value,
869    "the specified hash does not meet the Hash requirements");
870    static_assert(is_copy_constructible<_Equal>::value,
871    "the specified comparator is required to be copy constructible");
872#endif
873    typedef int type;
874};
875
876template <class _Key, class _Hash, class _Equal>
877#ifndef _LIBCPP_CXX03_LANG
878    _LIBCPP_DIAGNOSE_WARNING(!__invokable<_Equal const&, _Key const&, _Key const&>::value,
879    "the specified comparator type does not provide a const call operator")
880    _LIBCPP_DIAGNOSE_WARNING(!__invokable<_Hash const&, _Key const&>::value,
881    "the specified hash functor does not provide a const call operator")
882#endif
883typename __enforce_unordered_container_requirements<_Key, _Hash, _Equal>::type
884__diagnose_unordered_container_requirements(int);
885
886// This dummy overload is used so that the compiler won't emit a spurious
887// "no matching function for call to __diagnose_unordered_xxx" diagnostic
888// when the overload above causes a hard error.
889template <class _Key, class _Hash, class _Equal>
890int __diagnose_unordered_container_requirements(void*);
891
892template <class _Tp, class _Hash, class _Equal, class _Alloc>
893class __hash_table
894{
895public:
896    typedef _Tp    value_type;
897    typedef _Hash  hasher;
898    typedef _Equal key_equal;
899    typedef _Alloc allocator_type;
900
901private:
902    typedef allocator_traits<allocator_type> __alloc_traits;
903    typedef typename
904      __make_hash_node_types<value_type, typename __alloc_traits::void_pointer>::type
905                                                                     _NodeTypes;
906public:
907
908    typedef typename _NodeTypes::__node_value_type           __node_value_type;
909    typedef typename _NodeTypes::__container_value_type      __container_value_type;
910    typedef typename _NodeTypes::key_type                    key_type;
911    typedef value_type&                              reference;
912    typedef const value_type&                        const_reference;
913    typedef typename __alloc_traits::pointer         pointer;
914    typedef typename __alloc_traits::const_pointer   const_pointer;
915#ifndef _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
916    typedef typename __alloc_traits::size_type       size_type;
917#else
918    typedef typename _NodeTypes::size_type           size_type;
919#endif
920    typedef typename _NodeTypes::difference_type     difference_type;
921public:
922    // Create __node
923
924    typedef typename _NodeTypes::__node_type __node;
925    typedef typename __rebind_alloc_helper<__alloc_traits, __node>::type __node_allocator;
926    typedef allocator_traits<__node_allocator>       __node_traits;
927    typedef typename _NodeTypes::__void_pointer      __void_pointer;
928    typedef typename _NodeTypes::__node_pointer      __node_pointer;
929    typedef typename _NodeTypes::__node_pointer      __node_const_pointer;
930    typedef typename _NodeTypes::__node_base_type    __first_node;
931    typedef typename _NodeTypes::__node_base_pointer __node_base_pointer;
932    typedef typename _NodeTypes::__next_pointer      __next_pointer;
933
934private:
935    // check for sane allocator pointer rebinding semantics. Rebinding the
936    // allocator for a new pointer type should be exactly the same as rebinding
937    // the pointer using 'pointer_traits'.
938    static_assert((is_same<__node_pointer, typename __node_traits::pointer>::value),
939                  "Allocator does not rebind pointers in a sane manner.");
940    typedef typename __rebind_alloc_helper<__node_traits, __first_node>::type
941        __node_base_allocator;
942    typedef allocator_traits<__node_base_allocator> __node_base_traits;
943    static_assert((is_same<__node_base_pointer, typename __node_base_traits::pointer>::value),
944                 "Allocator does not rebind pointers in a sane manner.");
945
946private:
947
948    typedef typename __rebind_alloc_helper<__node_traits, __next_pointer>::type __pointer_allocator;
949    typedef __bucket_list_deallocator<__pointer_allocator> __bucket_list_deleter;
950    typedef unique_ptr<__next_pointer[], __bucket_list_deleter> __bucket_list;
951    typedef allocator_traits<__pointer_allocator>          __pointer_alloc_traits;
952    typedef typename __bucket_list_deleter::pointer       __node_pointer_pointer;
953
954    // --- Member data begin ---
955    __bucket_list                                         __bucket_list_;
956    __compressed_pair<__first_node, __node_allocator>     __p1_;
957    __compressed_pair<size_type, hasher>                  __p2_;
958    __compressed_pair<float, key_equal>                   __p3_;
959    // --- Member data end ---
960
961    _LIBCPP_INLINE_VISIBILITY
962    size_type& size() _NOEXCEPT {return __p2_.first();}
963public:
964    _LIBCPP_INLINE_VISIBILITY
965    size_type  size() const _NOEXCEPT {return __p2_.first();}
966
967    _LIBCPP_INLINE_VISIBILITY
968    hasher& hash_function() _NOEXCEPT {return __p2_.second();}
969    _LIBCPP_INLINE_VISIBILITY
970    const hasher& hash_function() const _NOEXCEPT {return __p2_.second();}
971
972    _LIBCPP_INLINE_VISIBILITY
973    float& max_load_factor() _NOEXCEPT {return __p3_.first();}
974    _LIBCPP_INLINE_VISIBILITY
975    float  max_load_factor() const _NOEXCEPT {return __p3_.first();}
976
977    _LIBCPP_INLINE_VISIBILITY
978    key_equal& key_eq() _NOEXCEPT {return __p3_.second();}
979    _LIBCPP_INLINE_VISIBILITY
980    const key_equal& key_eq() const _NOEXCEPT {return __p3_.second();}
981
982    _LIBCPP_INLINE_VISIBILITY
983    __node_allocator& __node_alloc() _NOEXCEPT {return __p1_.second();}
984    _LIBCPP_INLINE_VISIBILITY
985    const __node_allocator& __node_alloc() const _NOEXCEPT
986        {return __p1_.second();}
987
988public:
989    typedef __hash_iterator<__node_pointer>                   iterator;
990    typedef __hash_const_iterator<__node_pointer>             const_iterator;
991    typedef __hash_local_iterator<__node_pointer>             local_iterator;
992    typedef __hash_const_local_iterator<__node_pointer>       const_local_iterator;
993
994    _LIBCPP_INLINE_VISIBILITY
995    __hash_table()
996        _NOEXCEPT_(
997            is_nothrow_default_constructible<__bucket_list>::value &&
998            is_nothrow_default_constructible<__first_node>::value &&
999            is_nothrow_default_constructible<__node_allocator>::value &&
1000            is_nothrow_default_constructible<hasher>::value &&
1001            is_nothrow_default_constructible<key_equal>::value);
1002    _LIBCPP_INLINE_VISIBILITY
1003    __hash_table(const hasher& __hf, const key_equal& __eql);
1004    __hash_table(const hasher& __hf, const key_equal& __eql,
1005                 const allocator_type& __a);
1006    explicit __hash_table(const allocator_type& __a);
1007    __hash_table(const __hash_table& __u);
1008    __hash_table(const __hash_table& __u, const allocator_type& __a);
1009#ifndef _LIBCPP_CXX03_LANG
1010    __hash_table(__hash_table&& __u)
1011        _NOEXCEPT_(
1012            is_nothrow_move_constructible<__bucket_list>::value &&
1013            is_nothrow_move_constructible<__first_node>::value &&
1014            is_nothrow_move_constructible<__node_allocator>::value &&
1015            is_nothrow_move_constructible<hasher>::value &&
1016            is_nothrow_move_constructible<key_equal>::value);
1017    __hash_table(__hash_table&& __u, const allocator_type& __a);
1018#endif  // _LIBCPP_CXX03_LANG
1019    ~__hash_table();
1020
1021    __hash_table& operator=(const __hash_table& __u);
1022#ifndef _LIBCPP_CXX03_LANG
1023    _LIBCPP_INLINE_VISIBILITY
1024    __hash_table& operator=(__hash_table&& __u)
1025        _NOEXCEPT_(
1026            __node_traits::propagate_on_container_move_assignment::value &&
1027            is_nothrow_move_assignable<__node_allocator>::value &&
1028            is_nothrow_move_assignable<hasher>::value &&
1029            is_nothrow_move_assignable<key_equal>::value);
1030#endif
1031    template <class _InputIterator>
1032        void __assign_unique(_InputIterator __first, _InputIterator __last);
1033    template <class _InputIterator>
1034        void __assign_multi(_InputIterator __first, _InputIterator __last);
1035
1036    _LIBCPP_INLINE_VISIBILITY
1037    size_type max_size() const _NOEXCEPT
1038    {
1039        return std::min<size_type>(
1040            __node_traits::max_size(__node_alloc()),
1041            numeric_limits<difference_type >::max()
1042        );
1043    }
1044
1045private:
1046    _LIBCPP_INLINE_VISIBILITY
1047    __next_pointer __node_insert_multi_prepare(size_t __cp_hash,
1048                                               value_type& __cp_val);
1049    _LIBCPP_INLINE_VISIBILITY
1050    void __node_insert_multi_perform(__node_pointer __cp,
1051                                     __next_pointer __pn) _NOEXCEPT;
1052
1053    _LIBCPP_INLINE_VISIBILITY
1054    __next_pointer __node_insert_unique_prepare(size_t __nd_hash,
1055                                                value_type& __nd_val);
1056    _LIBCPP_INLINE_VISIBILITY
1057    void __node_insert_unique_perform(__node_pointer __ptr) _NOEXCEPT;
1058
1059public:
1060    _LIBCPP_INLINE_VISIBILITY
1061    pair<iterator, bool> __node_insert_unique(__node_pointer __nd);
1062    _LIBCPP_INLINE_VISIBILITY
1063    iterator             __node_insert_multi(__node_pointer __nd);
1064    _LIBCPP_INLINE_VISIBILITY
1065    iterator             __node_insert_multi(const_iterator __p,
1066                                             __node_pointer __nd);
1067
1068#ifndef _LIBCPP_CXX03_LANG
1069    template <class _Key, class ..._Args>
1070    _LIBCPP_INLINE_VISIBILITY
1071    pair<iterator, bool> __emplace_unique_key_args(_Key const& __k, _Args&&... __args);
1072
1073    template <class... _Args>
1074    _LIBCPP_INLINE_VISIBILITY
1075    pair<iterator, bool> __emplace_unique_impl(_Args&&... __args);
1076
1077    template <class _Pp>
1078    _LIBCPP_INLINE_VISIBILITY
1079    pair<iterator, bool> __emplace_unique(_Pp&& __x) {
1080      return __emplace_unique_extract_key(_VSTD::forward<_Pp>(__x),
1081                                          __can_extract_key<_Pp, key_type>());
1082    }
1083
1084    template <class _First, class _Second>
1085    _LIBCPP_INLINE_VISIBILITY
1086    typename enable_if<
1087        __can_extract_map_key<_First, key_type, __container_value_type>::value,
1088        pair<iterator, bool>
1089    >::type __emplace_unique(_First&& __f, _Second&& __s) {
1090        return __emplace_unique_key_args(__f, _VSTD::forward<_First>(__f),
1091                                              _VSTD::forward<_Second>(__s));
1092    }
1093
1094    template <class... _Args>
1095    _LIBCPP_INLINE_VISIBILITY
1096    pair<iterator, bool> __emplace_unique(_Args&&... __args) {
1097      return __emplace_unique_impl(_VSTD::forward<_Args>(__args)...);
1098    }
1099
1100    template <class _Pp>
1101    _LIBCPP_INLINE_VISIBILITY
1102    pair<iterator, bool>
1103    __emplace_unique_extract_key(_Pp&& __x, __extract_key_fail_tag) {
1104      return __emplace_unique_impl(_VSTD::forward<_Pp>(__x));
1105    }
1106    template <class _Pp>
1107    _LIBCPP_INLINE_VISIBILITY
1108    pair<iterator, bool>
1109    __emplace_unique_extract_key(_Pp&& __x, __extract_key_self_tag) {
1110      return __emplace_unique_key_args(__x, _VSTD::forward<_Pp>(__x));
1111    }
1112    template <class _Pp>
1113    _LIBCPP_INLINE_VISIBILITY
1114    pair<iterator, bool>
1115    __emplace_unique_extract_key(_Pp&& __x, __extract_key_first_tag) {
1116      return __emplace_unique_key_args(__x.first, _VSTD::forward<_Pp>(__x));
1117    }
1118
1119    template <class... _Args>
1120    _LIBCPP_INLINE_VISIBILITY
1121    iterator __emplace_multi(_Args&&... __args);
1122    template <class... _Args>
1123    _LIBCPP_INLINE_VISIBILITY
1124    iterator __emplace_hint_multi(const_iterator __p, _Args&&... __args);
1125
1126
1127    _LIBCPP_INLINE_VISIBILITY
1128    pair<iterator, bool>
1129    __insert_unique(__container_value_type&& __x) {
1130      return __emplace_unique_key_args(_NodeTypes::__get_key(__x), _VSTD::move(__x));
1131    }
1132
1133    template <class _Pp, class = typename enable_if<
1134            !__is_same_uncvref<_Pp, __container_value_type>::value
1135        >::type>
1136    _LIBCPP_INLINE_VISIBILITY
1137    pair<iterator, bool> __insert_unique(_Pp&& __x) {
1138      return __emplace_unique(_VSTD::forward<_Pp>(__x));
1139    }
1140
1141    template <class _Pp>
1142    _LIBCPP_INLINE_VISIBILITY
1143    iterator __insert_multi(_Pp&& __x) {
1144      return __emplace_multi(_VSTD::forward<_Pp>(__x));
1145    }
1146
1147    template <class _Pp>
1148    _LIBCPP_INLINE_VISIBILITY
1149    iterator __insert_multi(const_iterator __p, _Pp&& __x) {
1150        return __emplace_hint_multi(__p, _VSTD::forward<_Pp>(__x));
1151    }
1152
1153#else  // !defined(_LIBCPP_CXX03_LANG)
1154    template <class _Key, class _Args>
1155    _LIBCPP_INLINE_VISIBILITY
1156    pair<iterator, bool> __emplace_unique_key_args(_Key const&, _Args& __args);
1157
1158    iterator __insert_multi(const __container_value_type& __x);
1159    iterator __insert_multi(const_iterator __p, const __container_value_type& __x);
1160#endif
1161
1162    _LIBCPP_INLINE_VISIBILITY
1163    pair<iterator, bool> __insert_unique(const __container_value_type& __x) {
1164        return __emplace_unique_key_args(_NodeTypes::__get_key(__x), __x);
1165    }
1166
1167#if _LIBCPP_STD_VER > 14
1168    template <class _NodeHandle, class _InsertReturnType>
1169    _LIBCPP_INLINE_VISIBILITY
1170    _InsertReturnType __node_handle_insert_unique(_NodeHandle&& __nh);
1171    template <class _NodeHandle>
1172    _LIBCPP_INLINE_VISIBILITY
1173    iterator __node_handle_insert_unique(const_iterator __hint,
1174                                         _NodeHandle&& __nh);
1175    template <class _Table>
1176    _LIBCPP_INLINE_VISIBILITY
1177    void __node_handle_merge_unique(_Table& __source);
1178
1179    template <class _NodeHandle>
1180    _LIBCPP_INLINE_VISIBILITY
1181    iterator __node_handle_insert_multi(_NodeHandle&& __nh);
1182    template <class _NodeHandle>
1183    _LIBCPP_INLINE_VISIBILITY
1184    iterator __node_handle_insert_multi(const_iterator __hint, _NodeHandle&& __nh);
1185    template <class _Table>
1186    _LIBCPP_INLINE_VISIBILITY
1187    void __node_handle_merge_multi(_Table& __source);
1188
1189    template <class _NodeHandle>
1190    _LIBCPP_INLINE_VISIBILITY
1191    _NodeHandle __node_handle_extract(key_type const& __key);
1192    template <class _NodeHandle>
1193    _LIBCPP_INLINE_VISIBILITY
1194    _NodeHandle __node_handle_extract(const_iterator __it);
1195#endif
1196
1197    void clear() _NOEXCEPT;
1198    void rehash(size_type __n);
1199    _LIBCPP_INLINE_VISIBILITY void reserve(size_type __n)
1200        {rehash(static_cast<size_type>(ceil(__n / max_load_factor())));}
1201
1202    _LIBCPP_INLINE_VISIBILITY
1203    size_type bucket_count() const _NOEXCEPT
1204    {
1205        return __bucket_list_.get_deleter().size();
1206    }
1207
1208    _LIBCPP_INLINE_VISIBILITY
1209    iterator       begin() _NOEXCEPT;
1210    _LIBCPP_INLINE_VISIBILITY
1211    iterator       end() _NOEXCEPT;
1212    _LIBCPP_INLINE_VISIBILITY
1213    const_iterator begin() const _NOEXCEPT;
1214    _LIBCPP_INLINE_VISIBILITY
1215    const_iterator end() const _NOEXCEPT;
1216
1217    template <class _Key>
1218        _LIBCPP_INLINE_VISIBILITY
1219        size_type bucket(const _Key& __k) const
1220        {
1221            _LIBCPP_ASSERT(bucket_count() > 0,
1222                "unordered container::bucket(key) called when bucket_count() == 0");
1223            return __constrain_hash(hash_function()(__k), bucket_count());
1224        }
1225
1226    template <class _Key>
1227        iterator       find(const _Key& __x);
1228    template <class _Key>
1229        const_iterator find(const _Key& __x) const;
1230
1231    typedef __hash_node_destructor<__node_allocator> _Dp;
1232    typedef unique_ptr<__node, _Dp> __node_holder;
1233
1234    iterator erase(const_iterator __p);
1235    iterator erase(const_iterator __first, const_iterator __last);
1236    template <class _Key>
1237        size_type __erase_unique(const _Key& __k);
1238    template <class _Key>
1239        size_type __erase_multi(const _Key& __k);
1240    __node_holder remove(const_iterator __p) _NOEXCEPT;
1241
1242    template <class _Key>
1243        _LIBCPP_INLINE_VISIBILITY
1244        size_type __count_unique(const _Key& __k) const;
1245    template <class _Key>
1246        size_type __count_multi(const _Key& __k) const;
1247
1248    template <class _Key>
1249        pair<iterator, iterator>
1250        __equal_range_unique(const _Key& __k);
1251    template <class _Key>
1252        pair<const_iterator, const_iterator>
1253        __equal_range_unique(const _Key& __k) const;
1254
1255    template <class _Key>
1256        pair<iterator, iterator>
1257        __equal_range_multi(const _Key& __k);
1258    template <class _Key>
1259        pair<const_iterator, const_iterator>
1260        __equal_range_multi(const _Key& __k) const;
1261
1262    void swap(__hash_table& __u)
1263#if _LIBCPP_STD_VER <= 11
1264        _NOEXCEPT_DEBUG_(
1265            __is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value
1266            && (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value
1267                  || __is_nothrow_swappable<__pointer_allocator>::value)
1268            && (!__node_traits::propagate_on_container_swap::value
1269                  || __is_nothrow_swappable<__node_allocator>::value)
1270            );
1271#else
1272     _NOEXCEPT_DEBUG_(__is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value);
1273#endif
1274
1275    _LIBCPP_INLINE_VISIBILITY
1276    size_type max_bucket_count() const _NOEXCEPT
1277        {return max_size(); }
1278    size_type bucket_size(size_type __n) const;
1279    _LIBCPP_INLINE_VISIBILITY float load_factor() const _NOEXCEPT
1280    {
1281        size_type __bc = bucket_count();
1282        return __bc != 0 ? (float)size() / __bc : 0.f;
1283    }
1284    _LIBCPP_INLINE_VISIBILITY void max_load_factor(float __mlf) _NOEXCEPT
1285    {
1286        _LIBCPP_ASSERT(__mlf > 0,
1287            "unordered container::max_load_factor(lf) called with lf <= 0");
1288        max_load_factor() = _VSTD::max(__mlf, load_factor());
1289    }
1290
1291    _LIBCPP_INLINE_VISIBILITY
1292    local_iterator
1293    begin(size_type __n)
1294    {
1295        _LIBCPP_ASSERT(__n < bucket_count(),
1296            "unordered container::begin(n) called with n >= bucket_count()");
1297#if _LIBCPP_DEBUG_LEVEL >= 2
1298        return local_iterator(__bucket_list_[__n], __n, bucket_count(), this);
1299#else
1300        return local_iterator(__bucket_list_[__n], __n, bucket_count());
1301#endif
1302    }
1303
1304    _LIBCPP_INLINE_VISIBILITY
1305    local_iterator
1306    end(size_type __n)
1307    {
1308        _LIBCPP_ASSERT(__n < bucket_count(),
1309            "unordered container::end(n) called with n >= bucket_count()");
1310#if _LIBCPP_DEBUG_LEVEL >= 2
1311        return local_iterator(nullptr, __n, bucket_count(), this);
1312#else
1313        return local_iterator(nullptr, __n, bucket_count());
1314#endif
1315    }
1316
1317    _LIBCPP_INLINE_VISIBILITY
1318    const_local_iterator
1319    cbegin(size_type __n) const
1320    {
1321        _LIBCPP_ASSERT(__n < bucket_count(),
1322            "unordered container::cbegin(n) called with n >= bucket_count()");
1323#if _LIBCPP_DEBUG_LEVEL >= 2
1324        return const_local_iterator(__bucket_list_[__n], __n, bucket_count(), this);
1325#else
1326        return const_local_iterator(__bucket_list_[__n], __n, bucket_count());
1327#endif
1328    }
1329
1330    _LIBCPP_INLINE_VISIBILITY
1331    const_local_iterator
1332    cend(size_type __n) const
1333    {
1334        _LIBCPP_ASSERT(__n < bucket_count(),
1335            "unordered container::cend(n) called with n >= bucket_count()");
1336#if _LIBCPP_DEBUG_LEVEL >= 2
1337        return const_local_iterator(nullptr, __n, bucket_count(), this);
1338#else
1339        return const_local_iterator(nullptr, __n, bucket_count());
1340#endif
1341    }
1342
1343#if _LIBCPP_DEBUG_LEVEL >= 2
1344
1345    bool __dereferenceable(const const_iterator* __i) const;
1346    bool __decrementable(const const_iterator* __i) const;
1347    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
1348    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
1349
1350#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1351
1352private:
1353    void __rehash(size_type __n);
1354
1355#ifndef _LIBCPP_CXX03_LANG
1356    template <class ..._Args>
1357    __node_holder __construct_node(_Args&& ...__args);
1358
1359    template <class _First, class ..._Rest>
1360    __node_holder __construct_node_hash(size_t __hash, _First&& __f, _Rest&&... __rest);
1361#else // _LIBCPP_CXX03_LANG
1362    __node_holder __construct_node(const __container_value_type& __v);
1363    __node_holder __construct_node_hash(size_t __hash, const __container_value_type& __v);
1364#endif
1365
1366
1367    _LIBCPP_INLINE_VISIBILITY
1368    void __copy_assign_alloc(const __hash_table& __u)
1369        {__copy_assign_alloc(__u, integral_constant<bool,
1370             __node_traits::propagate_on_container_copy_assignment::value>());}
1371    void __copy_assign_alloc(const __hash_table& __u, true_type);
1372    _LIBCPP_INLINE_VISIBILITY
1373        void __copy_assign_alloc(const __hash_table&, false_type) {}
1374
1375#ifndef _LIBCPP_CXX03_LANG
1376    void __move_assign(__hash_table& __u, false_type);
1377    void __move_assign(__hash_table& __u, true_type)
1378        _NOEXCEPT_(
1379            is_nothrow_move_assignable<__node_allocator>::value &&
1380            is_nothrow_move_assignable<hasher>::value &&
1381            is_nothrow_move_assignable<key_equal>::value);
1382    _LIBCPP_INLINE_VISIBILITY
1383    void __move_assign_alloc(__hash_table& __u)
1384        _NOEXCEPT_(
1385            !__node_traits::propagate_on_container_move_assignment::value ||
1386            (is_nothrow_move_assignable<__pointer_allocator>::value &&
1387             is_nothrow_move_assignable<__node_allocator>::value))
1388        {__move_assign_alloc(__u, integral_constant<bool,
1389             __node_traits::propagate_on_container_move_assignment::value>());}
1390    _LIBCPP_INLINE_VISIBILITY
1391    void __move_assign_alloc(__hash_table& __u, true_type)
1392        _NOEXCEPT_(
1393            is_nothrow_move_assignable<__pointer_allocator>::value &&
1394            is_nothrow_move_assignable<__node_allocator>::value)
1395    {
1396        __bucket_list_.get_deleter().__alloc() =
1397                _VSTD::move(__u.__bucket_list_.get_deleter().__alloc());
1398        __node_alloc() = _VSTD::move(__u.__node_alloc());
1399    }
1400    _LIBCPP_INLINE_VISIBILITY
1401        void __move_assign_alloc(__hash_table&, false_type) _NOEXCEPT {}
1402#endif // _LIBCPP_CXX03_LANG
1403
1404    void __deallocate_node(__next_pointer __np) _NOEXCEPT;
1405    __next_pointer __detach() _NOEXCEPT;
1406
1407    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
1408    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
1409};
1410
1411template <class _Tp, class _Hash, class _Equal, class _Alloc>
1412inline
1413__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table()
1414    _NOEXCEPT_(
1415        is_nothrow_default_constructible<__bucket_list>::value &&
1416        is_nothrow_default_constructible<__first_node>::value &&
1417        is_nothrow_default_constructible<__node_allocator>::value &&
1418        is_nothrow_default_constructible<hasher>::value &&
1419        is_nothrow_default_constructible<key_equal>::value)
1420    : __p2_(0),
1421      __p3_(1.0f)
1422{
1423}
1424
1425template <class _Tp, class _Hash, class _Equal, class _Alloc>
1426inline
1427__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const hasher& __hf,
1428                                                       const key_equal& __eql)
1429    : __bucket_list_(nullptr, __bucket_list_deleter()),
1430      __p1_(),
1431      __p2_(0, __hf),
1432      __p3_(1.0f, __eql)
1433{
1434}
1435
1436template <class _Tp, class _Hash, class _Equal, class _Alloc>
1437__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const hasher& __hf,
1438                                                       const key_equal& __eql,
1439                                                       const allocator_type& __a)
1440    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1441      __p1_(__second_tag(), __node_allocator(__a)),
1442      __p2_(0, __hf),
1443      __p3_(1.0f, __eql)
1444{
1445}
1446
1447template <class _Tp, class _Hash, class _Equal, class _Alloc>
1448__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const allocator_type& __a)
1449    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1450      __p1_(__second_tag(), __node_allocator(__a)),
1451      __p2_(0),
1452      __p3_(1.0f)
1453{
1454}
1455
1456template <class _Tp, class _Hash, class _Equal, class _Alloc>
1457__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u)
1458    : __bucket_list_(nullptr,
1459          __bucket_list_deleter(allocator_traits<__pointer_allocator>::
1460              select_on_container_copy_construction(
1461                  __u.__bucket_list_.get_deleter().__alloc()), 0)),
1462      __p1_(__second_tag(), allocator_traits<__node_allocator>::
1463          select_on_container_copy_construction(__u.__node_alloc())),
1464      __p2_(0, __u.hash_function()),
1465      __p3_(__u.__p3_)
1466{
1467}
1468
1469template <class _Tp, class _Hash, class _Equal, class _Alloc>
1470__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u,
1471                                                       const allocator_type& __a)
1472    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1473      __p1_(__second_tag(), __node_allocator(__a)),
1474      __p2_(0, __u.hash_function()),
1475      __p3_(__u.__p3_)
1476{
1477}
1478
1479#ifndef _LIBCPP_CXX03_LANG
1480
1481template <class _Tp, class _Hash, class _Equal, class _Alloc>
1482__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u)
1483        _NOEXCEPT_(
1484            is_nothrow_move_constructible<__bucket_list>::value &&
1485            is_nothrow_move_constructible<__first_node>::value &&
1486            is_nothrow_move_constructible<__node_allocator>::value &&
1487            is_nothrow_move_constructible<hasher>::value &&
1488            is_nothrow_move_constructible<key_equal>::value)
1489    : __bucket_list_(_VSTD::move(__u.__bucket_list_)),
1490      __p1_(_VSTD::move(__u.__p1_)),
1491      __p2_(_VSTD::move(__u.__p2_)),
1492      __p3_(_VSTD::move(__u.__p3_))
1493{
1494    if (size() > 0)
1495    {
1496        __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
1497            __p1_.first().__ptr();
1498        __u.__p1_.first().__next_ = nullptr;
1499        __u.size() = 0;
1500    }
1501}
1502
1503template <class _Tp, class _Hash, class _Equal, class _Alloc>
1504__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u,
1505                                                       const allocator_type& __a)
1506    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1507      __p1_(__second_tag(), __node_allocator(__a)),
1508      __p2_(0, _VSTD::move(__u.hash_function())),
1509      __p3_(_VSTD::move(__u.__p3_))
1510{
1511    if (__a == allocator_type(__u.__node_alloc()))
1512    {
1513        __bucket_list_.reset(__u.__bucket_list_.release());
1514        __bucket_list_.get_deleter().size() = __u.__bucket_list_.get_deleter().size();
1515        __u.__bucket_list_.get_deleter().size() = 0;
1516        if (__u.size() > 0)
1517        {
1518            __p1_.first().__next_ = __u.__p1_.first().__next_;
1519            __u.__p1_.first().__next_ = nullptr;
1520            __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
1521                __p1_.first().__ptr();
1522            size() = __u.size();
1523            __u.size() = 0;
1524        }
1525    }
1526}
1527
1528#endif  // _LIBCPP_CXX03_LANG
1529
1530template <class _Tp, class _Hash, class _Equal, class _Alloc>
1531__hash_table<_Tp, _Hash, _Equal, _Alloc>::~__hash_table()
1532{
1533#if defined(_LIBCPP_CXX03_LANG)
1534    static_assert((is_copy_constructible<key_equal>::value),
1535                 "Predicate must be copy-constructible.");
1536    static_assert((is_copy_constructible<hasher>::value),
1537                 "Hasher must be copy-constructible.");
1538#endif
1539
1540    __deallocate_node(__p1_.first().__next_);
1541#if _LIBCPP_DEBUG_LEVEL >= 2
1542    __get_db()->__erase_c(this);
1543#endif
1544}
1545
1546template <class _Tp, class _Hash, class _Equal, class _Alloc>
1547void
1548__hash_table<_Tp, _Hash, _Equal, _Alloc>::__copy_assign_alloc(
1549        const __hash_table& __u, true_type)
1550{
1551    if (__node_alloc() != __u.__node_alloc())
1552    {
1553        clear();
1554        __bucket_list_.reset();
1555        __bucket_list_.get_deleter().size() = 0;
1556    }
1557    __bucket_list_.get_deleter().__alloc() = __u.__bucket_list_.get_deleter().__alloc();
1558    __node_alloc() = __u.__node_alloc();
1559}
1560
1561template <class _Tp, class _Hash, class _Equal, class _Alloc>
1562__hash_table<_Tp, _Hash, _Equal, _Alloc>&
1563__hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(const __hash_table& __u)
1564{
1565    if (this != &__u)
1566    {
1567        __copy_assign_alloc(__u);
1568        hash_function() = __u.hash_function();
1569        key_eq() = __u.key_eq();
1570        max_load_factor() = __u.max_load_factor();
1571        __assign_multi(__u.begin(), __u.end());
1572    }
1573    return *this;
1574}
1575
1576template <class _Tp, class _Hash, class _Equal, class _Alloc>
1577void
1578__hash_table<_Tp, _Hash, _Equal, _Alloc>::__deallocate_node(__next_pointer __np)
1579    _NOEXCEPT
1580{
1581    __node_allocator& __na = __node_alloc();
1582    while (__np != nullptr)
1583    {
1584        __next_pointer __next = __np->__next_;
1585#if _LIBCPP_DEBUG_LEVEL >= 2
1586        __c_node* __c = __get_db()->__find_c_and_lock(this);
1587        for (__i_node** __p = __c->end_; __p != __c->beg_; )
1588        {
1589            --__p;
1590            iterator* __i = static_cast<iterator*>((*__p)->__i_);
1591            if (__i->__node_ == __np)
1592            {
1593                (*__p)->__c_ = nullptr;
1594                if (--__c->end_ != __p)
1595                    memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
1596            }
1597        }
1598        __get_db()->unlock();
1599#endif
1600        __node_pointer __real_np = __np->__upcast();
1601        __node_traits::destroy(__na, _NodeTypes::__get_ptr(__real_np->__value_));
1602        __node_traits::deallocate(__na, __real_np, 1);
1603        __np = __next;
1604    }
1605}
1606
1607template <class _Tp, class _Hash, class _Equal, class _Alloc>
1608typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1609__hash_table<_Tp, _Hash, _Equal, _Alloc>::__detach() _NOEXCEPT
1610{
1611    size_type __bc = bucket_count();
1612    for (size_type __i = 0; __i < __bc; ++__i)
1613        __bucket_list_[__i] = nullptr;
1614    size() = 0;
1615    __next_pointer __cache = __p1_.first().__next_;
1616    __p1_.first().__next_ = nullptr;
1617    return __cache;
1618}
1619
1620#ifndef _LIBCPP_CXX03_LANG
1621
1622template <class _Tp, class _Hash, class _Equal, class _Alloc>
1623void
1624__hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(
1625        __hash_table& __u, true_type)
1626    _NOEXCEPT_(
1627        is_nothrow_move_assignable<__node_allocator>::value &&
1628        is_nothrow_move_assignable<hasher>::value &&
1629        is_nothrow_move_assignable<key_equal>::value)
1630{
1631    clear();
1632    __bucket_list_.reset(__u.__bucket_list_.release());
1633    __bucket_list_.get_deleter().size() = __u.__bucket_list_.get_deleter().size();
1634    __u.__bucket_list_.get_deleter().size() = 0;
1635    __move_assign_alloc(__u);
1636    size() = __u.size();
1637    hash_function() = _VSTD::move(__u.hash_function());
1638    max_load_factor() = __u.max_load_factor();
1639    key_eq() = _VSTD::move(__u.key_eq());
1640    __p1_.first().__next_ = __u.__p1_.first().__next_;
1641    if (size() > 0)
1642    {
1643        __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
1644            __p1_.first().__ptr();
1645        __u.__p1_.first().__next_ = nullptr;
1646        __u.size() = 0;
1647    }
1648#if _LIBCPP_DEBUG_LEVEL >= 2
1649    __get_db()->swap(this, &__u);
1650#endif
1651}
1652
1653template <class _Tp, class _Hash, class _Equal, class _Alloc>
1654void
1655__hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(
1656        __hash_table& __u, false_type)
1657{
1658    if (__node_alloc() == __u.__node_alloc())
1659        __move_assign(__u, true_type());
1660    else
1661    {
1662        hash_function() = _VSTD::move(__u.hash_function());
1663        key_eq() = _VSTD::move(__u.key_eq());
1664        max_load_factor() = __u.max_load_factor();
1665        if (bucket_count() != 0)
1666        {
1667            __next_pointer __cache = __detach();
1668#ifndef _LIBCPP_NO_EXCEPTIONS
1669            try
1670            {
1671#endif  // _LIBCPP_NO_EXCEPTIONS
1672                const_iterator __i = __u.begin();
1673                while (__cache != nullptr && __u.size() != 0)
1674                {
1675                    __cache->__upcast()->__value_ =
1676                        _VSTD::move(__u.remove(__i++)->__value_);
1677                    __next_pointer __next = __cache->__next_;
1678                    __node_insert_multi(__cache->__upcast());
1679                    __cache = __next;
1680                }
1681#ifndef _LIBCPP_NO_EXCEPTIONS
1682            }
1683            catch (...)
1684            {
1685                __deallocate_node(__cache);
1686                throw;
1687            }
1688#endif  // _LIBCPP_NO_EXCEPTIONS
1689            __deallocate_node(__cache);
1690        }
1691        const_iterator __i = __u.begin();
1692        while (__u.size() != 0)
1693        {
1694            __node_holder __h = __construct_node(_NodeTypes::__move(__u.remove(__i++)->__value_));
1695            __node_insert_multi(__h.get());
1696            __h.release();
1697        }
1698    }
1699}
1700
1701template <class _Tp, class _Hash, class _Equal, class _Alloc>
1702inline
1703__hash_table<_Tp, _Hash, _Equal, _Alloc>&
1704__hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(__hash_table&& __u)
1705    _NOEXCEPT_(
1706        __node_traits::propagate_on_container_move_assignment::value &&
1707        is_nothrow_move_assignable<__node_allocator>::value &&
1708        is_nothrow_move_assignable<hasher>::value &&
1709        is_nothrow_move_assignable<key_equal>::value)
1710{
1711    __move_assign(__u, integral_constant<bool,
1712                  __node_traits::propagate_on_container_move_assignment::value>());
1713    return *this;
1714}
1715
1716#endif  // _LIBCPP_CXX03_LANG
1717
1718template <class _Tp, class _Hash, class _Equal, class _Alloc>
1719template <class _InputIterator>
1720void
1721__hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_unique(_InputIterator __first,
1722                                                          _InputIterator __last)
1723{
1724    typedef iterator_traits<_InputIterator> _ITraits;
1725    typedef typename _ITraits::value_type _ItValueType;
1726    static_assert((is_same<_ItValueType, __container_value_type>::value),
1727                  "__assign_unique may only be called with the containers value type");
1728
1729    if (bucket_count() != 0)
1730    {
1731        __next_pointer __cache = __detach();
1732#ifndef _LIBCPP_NO_EXCEPTIONS
1733        try
1734        {
1735#endif  // _LIBCPP_NO_EXCEPTIONS
1736            for (; __cache != nullptr && __first != __last; ++__first)
1737            {
1738                __cache->__upcast()->__value_ = *__first;
1739                __next_pointer __next = __cache->__next_;
1740                __node_insert_unique(__cache->__upcast());
1741                __cache = __next;
1742            }
1743#ifndef _LIBCPP_NO_EXCEPTIONS
1744        }
1745        catch (...)
1746        {
1747            __deallocate_node(__cache);
1748            throw;
1749        }
1750#endif  // _LIBCPP_NO_EXCEPTIONS
1751        __deallocate_node(__cache);
1752    }
1753    for (; __first != __last; ++__first)
1754        __insert_unique(*__first);
1755}
1756
1757template <class _Tp, class _Hash, class _Equal, class _Alloc>
1758template <class _InputIterator>
1759void
1760__hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_multi(_InputIterator __first,
1761                                                         _InputIterator __last)
1762{
1763    typedef iterator_traits<_InputIterator> _ITraits;
1764    typedef typename _ITraits::value_type _ItValueType;
1765    static_assert((is_same<_ItValueType, __container_value_type>::value ||
1766                  is_same<_ItValueType, __node_value_type>::value),
1767                  "__assign_multi may only be called with the containers value type"
1768                  " or the nodes value type");
1769    if (bucket_count() != 0)
1770    {
1771        __next_pointer __cache = __detach();
1772#ifndef _LIBCPP_NO_EXCEPTIONS
1773        try
1774        {
1775#endif  // _LIBCPP_NO_EXCEPTIONS
1776            for (; __cache != nullptr && __first != __last; ++__first)
1777            {
1778                __cache->__upcast()->__value_ = *__first;
1779                __next_pointer __next = __cache->__next_;
1780                __node_insert_multi(__cache->__upcast());
1781                __cache = __next;
1782            }
1783#ifndef _LIBCPP_NO_EXCEPTIONS
1784        }
1785        catch (...)
1786        {
1787            __deallocate_node(__cache);
1788            throw;
1789        }
1790#endif  // _LIBCPP_NO_EXCEPTIONS
1791        __deallocate_node(__cache);
1792    }
1793    for (; __first != __last; ++__first)
1794        __insert_multi(_NodeTypes::__get_value(*__first));
1795}
1796
1797template <class _Tp, class _Hash, class _Equal, class _Alloc>
1798inline
1799typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1800__hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() _NOEXCEPT
1801{
1802#if _LIBCPP_DEBUG_LEVEL >= 2
1803    return iterator(__p1_.first().__next_, this);
1804#else
1805    return iterator(__p1_.first().__next_);
1806#endif
1807}
1808
1809template <class _Tp, class _Hash, class _Equal, class _Alloc>
1810inline
1811typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1812__hash_table<_Tp, _Hash, _Equal, _Alloc>::end() _NOEXCEPT
1813{
1814#if _LIBCPP_DEBUG_LEVEL >= 2
1815    return iterator(nullptr, this);
1816#else
1817    return iterator(nullptr);
1818#endif
1819}
1820
1821template <class _Tp, class _Hash, class _Equal, class _Alloc>
1822inline
1823typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
1824__hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() const _NOEXCEPT
1825{
1826#if _LIBCPP_DEBUG_LEVEL >= 2
1827    return const_iterator(__p1_.first().__next_, this);
1828#else
1829    return const_iterator(__p1_.first().__next_);
1830#endif
1831}
1832
1833template <class _Tp, class _Hash, class _Equal, class _Alloc>
1834inline
1835typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
1836__hash_table<_Tp, _Hash, _Equal, _Alloc>::end() const _NOEXCEPT
1837{
1838#if _LIBCPP_DEBUG_LEVEL >= 2
1839    return const_iterator(nullptr, this);
1840#else
1841    return const_iterator(nullptr);
1842#endif
1843}
1844
1845template <class _Tp, class _Hash, class _Equal, class _Alloc>
1846void
1847__hash_table<_Tp, _Hash, _Equal, _Alloc>::clear() _NOEXCEPT
1848{
1849    if (size() > 0)
1850    {
1851        __deallocate_node(__p1_.first().__next_);
1852        __p1_.first().__next_ = nullptr;
1853        size_type __bc = bucket_count();
1854        for (size_type __i = 0; __i < __bc; ++__i)
1855            __bucket_list_[__i] = nullptr;
1856        size() = 0;
1857    }
1858}
1859
1860
1861// Prepare the container for an insertion of the value __value with the hash
1862// __hash. This does a lookup into the container to see if __value is already
1863// present, and performs a rehash if necessary. Returns a pointer to the
1864// existing element if it exists, otherwise nullptr.
1865//
1866// Note that this function does forward exceptions if key_eq() throws, and never
1867// mutates __value or actually inserts into the map.
1868template <class _Tp, class _Hash, class _Equal, class _Alloc>
1869_LIBCPP_INLINE_VISIBILITY
1870typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1871__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique_prepare(
1872    size_t __hash, value_type& __value)
1873{
1874    size_type __bc = bucket_count();
1875
1876    if (__bc != 0)
1877    {
1878        size_t __chash = __constrain_hash(__hash, __bc);
1879        __next_pointer __ndptr = __bucket_list_[__chash];
1880        if (__ndptr != nullptr)
1881        {
1882            for (__ndptr = __ndptr->__next_; __ndptr != nullptr &&
1883                                             __constrain_hash(__ndptr->__hash(), __bc) == __chash;
1884                                                     __ndptr = __ndptr->__next_)
1885            {
1886                if (key_eq()(__ndptr->__upcast()->__value_, __value))
1887                    return __ndptr;
1888            }
1889        }
1890    }
1891    if (size()+1 > __bc * max_load_factor() || __bc == 0)
1892    {
1893        rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
1894                                     size_type(ceil(float(size() + 1) / max_load_factor()))));
1895    }
1896    return nullptr;
1897}
1898
1899// Insert the node __nd into the container by pushing it into the right bucket,
1900// and updating size(). Assumes that __nd->__hash is up-to-date, and that
1901// rehashing has already occurred and that no element with the same key exists
1902// in the map.
1903template <class _Tp, class _Hash, class _Equal, class _Alloc>
1904_LIBCPP_INLINE_VISIBILITY
1905void
1906__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique_perform(
1907    __node_pointer __nd) _NOEXCEPT
1908{
1909    size_type __bc = bucket_count();
1910    size_t __chash = __constrain_hash(__nd->__hash(), __bc);
1911    // insert_after __bucket_list_[__chash], or __first_node if bucket is null
1912    __next_pointer __pn = __bucket_list_[__chash];
1913    if (__pn == nullptr)
1914    {
1915        __pn =__p1_.first().__ptr();
1916        __nd->__next_ = __pn->__next_;
1917        __pn->__next_ = __nd->__ptr();
1918        // fix up __bucket_list_
1919        __bucket_list_[__chash] = __pn;
1920        if (__nd->__next_ != nullptr)
1921            __bucket_list_[__constrain_hash(__nd->__next_->__hash(), __bc)] = __nd->__ptr();
1922    }
1923    else
1924    {
1925        __nd->__next_ = __pn->__next_;
1926        __pn->__next_ = __nd->__ptr();
1927    }
1928    ++size();
1929}
1930
1931template <class _Tp, class _Hash, class _Equal, class _Alloc>
1932pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
1933__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique(__node_pointer __nd)
1934{
1935    __nd->__hash_ = hash_function()(__nd->__value_);
1936    __next_pointer __existing_node =
1937        __node_insert_unique_prepare(__nd->__hash(), __nd->__value_);
1938
1939    // Insert the node, unless it already exists in the container.
1940    bool __inserted = false;
1941    if (__existing_node == nullptr)
1942    {
1943        __node_insert_unique_perform(__nd);
1944        __existing_node = __nd->__ptr();
1945        __inserted = true;
1946    }
1947#if _LIBCPP_DEBUG_LEVEL >= 2
1948    return pair<iterator, bool>(iterator(__existing_node, this), __inserted);
1949#else
1950    return pair<iterator, bool>(iterator(__existing_node), __inserted);
1951#endif
1952}
1953
1954// Prepare the container for an insertion of the value __cp_val with the hash
1955// __cp_hash. This does a lookup into the container to see if __cp_value is
1956// already present, and performs a rehash if necessary. Returns a pointer to the
1957// last occurance of __cp_val in the map.
1958//
1959// Note that this function does forward exceptions if key_eq() throws, and never
1960// mutates __value or actually inserts into the map.
1961template <class _Tp, class _Hash, class _Equal, class _Alloc>
1962typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1963__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi_prepare(
1964    size_t __cp_hash, value_type& __cp_val)
1965{
1966    size_type __bc = bucket_count();
1967    if (size()+1 > __bc * max_load_factor() || __bc == 0)
1968    {
1969        rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
1970                       size_type(ceil(float(size() + 1) / max_load_factor()))));
1971        __bc = bucket_count();
1972    }
1973    size_t __chash = __constrain_hash(__cp_hash, __bc);
1974    __next_pointer __pn = __bucket_list_[__chash];
1975    if (__pn != nullptr)
1976    {
1977        for (bool __found = false; __pn->__next_ != nullptr &&
1978                                   __constrain_hash(__pn->__next_->__hash(), __bc) == __chash;
1979                                                           __pn = __pn->__next_)
1980        {
1981            //      __found    key_eq()     action
1982            //      false       false       loop
1983            //      true        true        loop
1984            //      false       true        set __found to true
1985            //      true        false       break
1986            if (__found != (__pn->__next_->__hash() == __cp_hash &&
1987                            key_eq()(__pn->__next_->__upcast()->__value_, __cp_val)))
1988            {
1989                if (!__found)
1990                    __found = true;
1991                else
1992                    break;
1993            }
1994        }
1995    }
1996    return __pn;
1997}
1998
1999// Insert the node __cp into the container after __pn (which is the last node in
2000// the bucket that compares equal to __cp). Rehashing, and checking for
2001// uniqueness has already been performed (in __node_insert_multi_prepare), so
2002// all we need to do is update the bucket and size(). Assumes that __cp->__hash
2003// is up-to-date.
2004template <class _Tp, class _Hash, class _Equal, class _Alloc>
2005void
2006__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi_perform(
2007    __node_pointer __cp, __next_pointer __pn) _NOEXCEPT
2008{
2009    size_type __bc = bucket_count();
2010    size_t __chash = __constrain_hash(__cp->__hash_, __bc);
2011    if (__pn == nullptr)
2012    {
2013        __pn =__p1_.first().__ptr();
2014        __cp->__next_ = __pn->__next_;
2015        __pn->__next_ = __cp->__ptr();
2016        // fix up __bucket_list_
2017        __bucket_list_[__chash] = __pn;
2018        if (__cp->__next_ != nullptr)
2019            __bucket_list_[__constrain_hash(__cp->__next_->__hash(), __bc)]
2020                = __cp->__ptr();
2021    }
2022    else
2023    {
2024        __cp->__next_ = __pn->__next_;
2025        __pn->__next_ = __cp->__ptr();
2026        if (__cp->__next_ != nullptr)
2027        {
2028            size_t __nhash = __constrain_hash(__cp->__next_->__hash(), __bc);
2029            if (__nhash != __chash)
2030                __bucket_list_[__nhash] = __cp->__ptr();
2031        }
2032    }
2033    ++size();
2034}
2035
2036
2037template <class _Tp, class _Hash, class _Equal, class _Alloc>
2038typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2039__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(__node_pointer __cp)
2040{
2041    __cp->__hash_ = hash_function()(__cp->__value_);
2042    __next_pointer __pn = __node_insert_multi_prepare(__cp->__hash(), __cp->__value_);
2043    __node_insert_multi_perform(__cp, __pn);
2044
2045#if _LIBCPP_DEBUG_LEVEL >= 2
2046    return iterator(__cp->__ptr(), this);
2047#else
2048    return iterator(__cp->__ptr());
2049#endif
2050}
2051
2052template <class _Tp, class _Hash, class _Equal, class _Alloc>
2053typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2054__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(
2055        const_iterator __p, __node_pointer __cp)
2056{
2057#if _LIBCPP_DEBUG_LEVEL >= 2
2058    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
2059        "unordered container::emplace_hint(const_iterator, args...) called with an iterator not"
2060        " referring to this unordered container");
2061#endif
2062    if (__p != end() && key_eq()(*__p, __cp->__value_))
2063    {
2064        __next_pointer __np = __p.__node_;
2065        __cp->__hash_ = __np->__hash();
2066        size_type __bc = bucket_count();
2067        if (size()+1 > __bc * max_load_factor() || __bc == 0)
2068        {
2069            rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
2070                           size_type(ceil(float(size() + 1) / max_load_factor()))));
2071            __bc = bucket_count();
2072        }
2073        size_t __chash = __constrain_hash(__cp->__hash_, __bc);
2074        __next_pointer __pp = __bucket_list_[__chash];
2075        while (__pp->__next_ != __np)
2076            __pp = __pp->__next_;
2077        __cp->__next_ = __np;
2078        __pp->__next_ = static_cast<__next_pointer>(__cp);
2079        ++size();
2080#if _LIBCPP_DEBUG_LEVEL >= 2
2081        return iterator(static_cast<__next_pointer>(__cp), this);
2082#else
2083        return iterator(static_cast<__next_pointer>(__cp));
2084#endif
2085    }
2086    return __node_insert_multi(__cp);
2087}
2088
2089
2090
2091#ifndef _LIBCPP_CXX03_LANG
2092template <class _Tp, class _Hash, class _Equal, class _Alloc>
2093template <class _Key, class ..._Args>
2094pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
2095__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const& __k, _Args&&... __args)
2096#else
2097template <class _Tp, class _Hash, class _Equal, class _Alloc>
2098template <class _Key, class _Args>
2099pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
2100__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const& __k, _Args& __args)
2101#endif
2102{
2103
2104    size_t __hash = hash_function()(__k);
2105    size_type __bc = bucket_count();
2106    bool __inserted = false;
2107    __next_pointer __nd;
2108    size_t __chash;
2109    if (__bc != 0)
2110    {
2111        __chash = __constrain_hash(__hash, __bc);
2112        __nd = __bucket_list_[__chash];
2113        if (__nd != nullptr)
2114        {
2115            for (__nd = __nd->__next_; __nd != nullptr &&
2116                (__nd->__hash() == __hash || __constrain_hash(__nd->__hash(), __bc) == __chash);
2117                                                           __nd = __nd->__next_)
2118            {
2119                if (key_eq()(__nd->__upcast()->__value_, __k))
2120                    goto __done;
2121            }
2122        }
2123    }
2124    {
2125#ifndef _LIBCPP_CXX03_LANG
2126        __node_holder __h = __construct_node_hash(__hash, _VSTD::forward<_Args>(__args)...);
2127#else
2128        __node_holder __h = __construct_node_hash(__hash, __args);
2129#endif
2130        if (size()+1 > __bc * max_load_factor() || __bc == 0)
2131        {
2132            rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
2133                           size_type(ceil(float(size() + 1) / max_load_factor()))));
2134            __bc = bucket_count();
2135            __chash = __constrain_hash(__hash, __bc);
2136        }
2137        // insert_after __bucket_list_[__chash], or __first_node if bucket is null
2138        __next_pointer __pn = __bucket_list_[__chash];
2139        if (__pn == nullptr)
2140        {
2141            __pn = __p1_.first().__ptr();
2142            __h->__next_ = __pn->__next_;
2143            __pn->__next_ = __h.get()->__ptr();
2144            // fix up __bucket_list_
2145            __bucket_list_[__chash] = __pn;
2146            if (__h->__next_ != nullptr)
2147                __bucket_list_[__constrain_hash(__h->__next_->__hash(), __bc)]
2148                    = __h.get()->__ptr();
2149        }
2150        else
2151        {
2152            __h->__next_ = __pn->__next_;
2153            __pn->__next_ = static_cast<__next_pointer>(__h.get());
2154        }
2155        __nd = static_cast<__next_pointer>(__h.release());
2156        // increment size
2157        ++size();
2158        __inserted = true;
2159    }
2160__done:
2161#if _LIBCPP_DEBUG_LEVEL >= 2
2162    return pair<iterator, bool>(iterator(__nd, this), __inserted);
2163#else
2164    return pair<iterator, bool>(iterator(__nd), __inserted);
2165#endif
2166}
2167
2168#ifndef _LIBCPP_CXX03_LANG
2169
2170template <class _Tp, class _Hash, class _Equal, class _Alloc>
2171template <class... _Args>
2172pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
2173__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_impl(_Args&&... __args)
2174{
2175    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
2176    pair<iterator, bool> __r = __node_insert_unique(__h.get());
2177    if (__r.second)
2178        __h.release();
2179    return __r;
2180}
2181
2182template <class _Tp, class _Hash, class _Equal, class _Alloc>
2183template <class... _Args>
2184typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2185__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_multi(_Args&&... __args)
2186{
2187    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
2188    iterator __r = __node_insert_multi(__h.get());
2189    __h.release();
2190    return __r;
2191}
2192
2193template <class _Tp, class _Hash, class _Equal, class _Alloc>
2194template <class... _Args>
2195typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2196__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_hint_multi(
2197        const_iterator __p, _Args&&... __args)
2198{
2199#if _LIBCPP_DEBUG_LEVEL >= 2
2200    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
2201        "unordered container::emplace_hint(const_iterator, args...) called with an iterator not"
2202        " referring to this unordered container");
2203#endif
2204    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
2205    iterator __r = __node_insert_multi(__p, __h.get());
2206    __h.release();
2207    return __r;
2208}
2209
2210#else // _LIBCPP_CXX03_LANG
2211
2212template <class _Tp, class _Hash, class _Equal, class _Alloc>
2213typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2214__hash_table<_Tp, _Hash, _Equal, _Alloc>::__insert_multi(const __container_value_type& __x)
2215{
2216    __node_holder __h = __construct_node(__x);
2217    iterator __r = __node_insert_multi(__h.get());
2218    __h.release();
2219    return __r;
2220}
2221
2222template <class _Tp, class _Hash, class _Equal, class _Alloc>
2223typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2224__hash_table<_Tp, _Hash, _Equal, _Alloc>::__insert_multi(const_iterator __p,
2225                                                         const __container_value_type& __x)
2226{
2227#if _LIBCPP_DEBUG_LEVEL >= 2
2228    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
2229        "unordered container::insert(const_iterator, lvalue) called with an iterator not"
2230        " referring to this unordered container");
2231#endif
2232    __node_holder __h = __construct_node(__x);
2233    iterator __r = __node_insert_multi(__p, __h.get());
2234    __h.release();
2235    return __r;
2236}
2237
2238#endif  // _LIBCPP_CXX03_LANG
2239
2240#if _LIBCPP_STD_VER > 14
2241template <class _Tp, class _Hash, class _Equal, class _Alloc>
2242template <class _NodeHandle, class _InsertReturnType>
2243_LIBCPP_INLINE_VISIBILITY
2244_InsertReturnType
2245__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_unique(
2246    _NodeHandle&& __nh)
2247{
2248    if (__nh.empty())
2249        return _InsertReturnType{end(), false, _NodeHandle()};
2250    pair<iterator, bool> __result = __node_insert_unique(__nh.__ptr_);
2251    if (__result.second)
2252        __nh.__release();
2253    return _InsertReturnType{__result.first, __result.second, _VSTD::move(__nh)};
2254}
2255
2256template <class _Tp, class _Hash, class _Equal, class _Alloc>
2257template <class _NodeHandle>
2258_LIBCPP_INLINE_VISIBILITY
2259typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2260__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_unique(
2261    const_iterator, _NodeHandle&& __nh)
2262{
2263    if (__nh.empty())
2264        return end();
2265    pair<iterator, bool> __result = __node_insert_unique(__nh.__ptr_);
2266    if (__result.second)
2267        __nh.__release();
2268    return __result.first;
2269}
2270
2271template <class _Tp, class _Hash, class _Equal, class _Alloc>
2272template <class _NodeHandle>
2273_LIBCPP_INLINE_VISIBILITY
2274_NodeHandle
2275__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_extract(
2276    key_type const& __key)
2277{
2278    iterator __i = find(__key);
2279    if (__i == end())
2280        return _NodeHandle();
2281    return __node_handle_extract<_NodeHandle>(__i);
2282}
2283
2284template <class _Tp, class _Hash, class _Equal, class _Alloc>
2285template <class _NodeHandle>
2286_LIBCPP_INLINE_VISIBILITY
2287_NodeHandle
2288__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_extract(
2289    const_iterator __p)
2290{
2291    allocator_type __alloc(__node_alloc());
2292    return _NodeHandle(remove(__p).release(), __alloc);
2293}
2294
2295template <class _Tp, class _Hash, class _Equal, class _Alloc>
2296template <class _Table>
2297_LIBCPP_INLINE_VISIBILITY
2298void
2299__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_merge_unique(
2300    _Table& __source)
2301{
2302    static_assert(is_same<__node, typename _Table::__node>::value, "");
2303
2304    for (typename _Table::iterator __it = __source.begin();
2305         __it != __source.end();)
2306    {
2307        __node_pointer __src_ptr = __it.__node_->__upcast();
2308        size_t __hash = hash_function()(__src_ptr->__value_);
2309        __next_pointer __existing_node =
2310            __node_insert_unique_prepare(__hash, __src_ptr->__value_);
2311        auto __prev_iter = __it++;
2312        if (__existing_node == nullptr)
2313        {
2314            (void)__source.remove(__prev_iter).release();
2315            __src_ptr->__hash_ = __hash;
2316            __node_insert_unique_perform(__src_ptr);
2317        }
2318    }
2319}
2320
2321template <class _Tp, class _Hash, class _Equal, class _Alloc>
2322template <class _NodeHandle>
2323_LIBCPP_INLINE_VISIBILITY
2324typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2325__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_multi(
2326    _NodeHandle&& __nh)
2327{
2328    if (__nh.empty())
2329        return end();
2330    iterator __result = __node_insert_multi(__nh.__ptr_);
2331    __nh.__release();
2332    return __result;
2333}
2334
2335template <class _Tp, class _Hash, class _Equal, class _Alloc>
2336template <class _NodeHandle>
2337_LIBCPP_INLINE_VISIBILITY
2338typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2339__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_multi(
2340    const_iterator __hint, _NodeHandle&& __nh)
2341{
2342    if (__nh.empty())
2343        return end();
2344    iterator __result = __node_insert_multi(__hint, __nh.__ptr_);
2345    __nh.__release();
2346    return __result;
2347}
2348
2349template <class _Tp, class _Hash, class _Equal, class _Alloc>
2350template <class _Table>
2351_LIBCPP_INLINE_VISIBILITY
2352void
2353__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_merge_multi(
2354    _Table& __source)
2355{
2356    static_assert(is_same<typename _Table::__node, __node>::value, "");
2357
2358    for (typename _Table::iterator __it = __source.begin();
2359         __it != __source.end();)
2360    {
2361        __node_pointer __src_ptr = __it.__node_->__upcast();
2362        size_t __src_hash = hash_function()(__src_ptr->__value_);
2363        __next_pointer __pn =
2364            __node_insert_multi_prepare(__src_hash, __src_ptr->__value_);
2365        (void)__source.remove(__it++).release();
2366        __src_ptr->__hash_ = __src_hash;
2367        __node_insert_multi_perform(__src_ptr, __pn);
2368    }
2369}
2370#endif  // _LIBCPP_STD_VER > 14
2371
2372template <class _Tp, class _Hash, class _Equal, class _Alloc>
2373void
2374__hash_table<_Tp, _Hash, _Equal, _Alloc>::rehash(size_type __n)
2375    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
2376{
2377    if (__n == 1)
2378        __n = 2;
2379    else if (__n & (__n - 1))
2380        __n = __next_prime(__n);
2381    size_type __bc = bucket_count();
2382    if (__n > __bc)
2383        __rehash(__n);
2384    else if (__n < __bc)
2385    {
2386        __n = _VSTD::max<size_type>
2387              (
2388                  __n,
2389                  __is_hash_power2(__bc) ? __next_hash_pow2(size_t(ceil(float(size()) / max_load_factor()))) :
2390                                           __next_prime(size_t(ceil(float(size()) / max_load_factor())))
2391              );
2392        if (__n < __bc)
2393            __rehash(__n);
2394    }
2395}
2396
2397template <class _Tp, class _Hash, class _Equal, class _Alloc>
2398void
2399__hash_table<_Tp, _Hash, _Equal, _Alloc>::__rehash(size_type __nbc)
2400{
2401#if _LIBCPP_DEBUG_LEVEL >= 2
2402    __get_db()->__invalidate_all(this);
2403#endif  // _LIBCPP_DEBUG_LEVEL >= 2
2404    __pointer_allocator& __npa = __bucket_list_.get_deleter().__alloc();
2405    __bucket_list_.reset(__nbc > 0 ?
2406                      __pointer_alloc_traits::allocate(__npa, __nbc) : nullptr);
2407    __bucket_list_.get_deleter().size() = __nbc;
2408    if (__nbc > 0)
2409    {
2410        for (size_type __i = 0; __i < __nbc; ++__i)
2411            __bucket_list_[__i] = nullptr;
2412        __next_pointer __pp = __p1_.first().__ptr();
2413        __next_pointer __cp = __pp->__next_;
2414        if (__cp != nullptr)
2415        {
2416            size_type __chash = __constrain_hash(__cp->__hash(), __nbc);
2417            __bucket_list_[__chash] = __pp;
2418            size_type __phash = __chash;
2419            for (__pp = __cp, __cp = __cp->__next_; __cp != nullptr;
2420                                                           __cp = __pp->__next_)
2421            {
2422                __chash = __constrain_hash(__cp->__hash(), __nbc);
2423                if (__chash == __phash)
2424                    __pp = __cp;
2425                else
2426                {
2427                    if (__bucket_list_[__chash] == nullptr)
2428                    {
2429                        __bucket_list_[__chash] = __pp;
2430                        __pp = __cp;
2431                        __phash = __chash;
2432                    }
2433                    else
2434                    {
2435                        __next_pointer __np = __cp;
2436                        for (; __np->__next_ != nullptr &&
2437                               key_eq()(__cp->__upcast()->__value_,
2438                                        __np->__next_->__upcast()->__value_);
2439                                                           __np = __np->__next_)
2440                            ;
2441                        __pp->__next_ = __np->__next_;
2442                        __np->__next_ = __bucket_list_[__chash]->__next_;
2443                        __bucket_list_[__chash]->__next_ = __cp;
2444
2445                    }
2446                }
2447            }
2448        }
2449    }
2450}
2451
2452template <class _Tp, class _Hash, class _Equal, class _Alloc>
2453template <class _Key>
2454typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2455__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k)
2456{
2457    size_t __hash = hash_function()(__k);
2458    size_type __bc = bucket_count();
2459    if (__bc != 0)
2460    {
2461        size_t __chash = __constrain_hash(__hash, __bc);
2462        __next_pointer __nd = __bucket_list_[__chash];
2463        if (__nd != nullptr)
2464        {
2465            for (__nd = __nd->__next_; __nd != nullptr &&
2466                (__nd->__hash() == __hash
2467                  || __constrain_hash(__nd->__hash(), __bc) == __chash);
2468                                                           __nd = __nd->__next_)
2469            {
2470                if ((__nd->__hash() == __hash)
2471                    && key_eq()(__nd->__upcast()->__value_, __k))
2472#if _LIBCPP_DEBUG_LEVEL >= 2
2473                    return iterator(__nd, this);
2474#else
2475                    return iterator(__nd);
2476#endif
2477            }
2478        }
2479    }
2480    return end();
2481}
2482
2483template <class _Tp, class _Hash, class _Equal, class _Alloc>
2484template <class _Key>
2485typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
2486__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k) const
2487{
2488    size_t __hash = hash_function()(__k);
2489    size_type __bc = bucket_count();
2490    if (__bc != 0)
2491    {
2492        size_t __chash = __constrain_hash(__hash, __bc);
2493        __next_pointer __nd = __bucket_list_[__chash];
2494        if (__nd != nullptr)
2495        {
2496            for (__nd = __nd->__next_; __nd != nullptr &&
2497                (__hash == __nd->__hash()
2498                    || __constrain_hash(__nd->__hash(), __bc) == __chash);
2499                                                           __nd = __nd->__next_)
2500            {
2501                if ((__nd->__hash() == __hash)
2502                    && key_eq()(__nd->__upcast()->__value_, __k))
2503#if _LIBCPP_DEBUG_LEVEL >= 2
2504                    return const_iterator(__nd, this);
2505#else
2506                    return const_iterator(__nd);
2507#endif
2508            }
2509        }
2510
2511    }
2512    return end();
2513}
2514
2515#ifndef _LIBCPP_CXX03_LANG
2516
2517template <class _Tp, class _Hash, class _Equal, class _Alloc>
2518template <class ..._Args>
2519typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2520__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node(_Args&& ...__args)
2521{
2522    static_assert(!__is_hash_value_type<_Args...>::value,
2523                  "Construct cannot be called with a hash value type");
2524    __node_allocator& __na = __node_alloc();
2525    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2526    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), _VSTD::forward<_Args>(__args)...);
2527    __h.get_deleter().__value_constructed = true;
2528    __h->__hash_ = hash_function()(__h->__value_);
2529    __h->__next_ = nullptr;
2530    return __h;
2531}
2532
2533template <class _Tp, class _Hash, class _Equal, class _Alloc>
2534template <class _First, class ..._Rest>
2535typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2536__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(
2537    size_t __hash, _First&& __f, _Rest&& ...__rest)
2538{
2539    static_assert(!__is_hash_value_type<_First, _Rest...>::value,
2540                  "Construct cannot be called with a hash value type");
2541    __node_allocator& __na = __node_alloc();
2542    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2543    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_),
2544                             _VSTD::forward<_First>(__f),
2545                             _VSTD::forward<_Rest>(__rest)...);
2546    __h.get_deleter().__value_constructed = true;
2547    __h->__hash_ = __hash;
2548    __h->__next_ = nullptr;
2549    return __h;
2550}
2551
2552#else  // _LIBCPP_CXX03_LANG
2553
2554template <class _Tp, class _Hash, class _Equal, class _Alloc>
2555typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2556__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node(const __container_value_type& __v)
2557{
2558    __node_allocator& __na = __node_alloc();
2559    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2560    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), __v);
2561    __h.get_deleter().__value_constructed = true;
2562    __h->__hash_ = hash_function()(__h->__value_);
2563    __h->__next_ = nullptr;
2564    return _LIBCPP_EXPLICIT_MOVE(__h);  // explicitly moved for C++03
2565}
2566
2567template <class _Tp, class _Hash, class _Equal, class _Alloc>
2568typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2569__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(size_t __hash,
2570                                                                const __container_value_type& __v)
2571{
2572    __node_allocator& __na = __node_alloc();
2573    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2574    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), __v);
2575    __h.get_deleter().__value_constructed = true;
2576    __h->__hash_ = __hash;
2577    __h->__next_ = nullptr;
2578    return _LIBCPP_EXPLICIT_MOVE(__h);  // explicitly moved for C++03
2579}
2580
2581#endif  // _LIBCPP_CXX03_LANG
2582
2583template <class _Tp, class _Hash, class _Equal, class _Alloc>
2584typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2585__hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __p)
2586{
2587    __next_pointer __np = __p.__node_;
2588#if _LIBCPP_DEBUG_LEVEL >= 2
2589    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
2590        "unordered container erase(iterator) called with an iterator not"
2591        " referring to this container");
2592    _LIBCPP_ASSERT(__p != end(),
2593        "unordered container erase(iterator) called with a non-dereferenceable iterator");
2594    iterator __r(__np, this);
2595#else
2596    iterator __r(__np);
2597#endif
2598    ++__r;
2599    remove(__p);
2600    return __r;
2601}
2602
2603template <class _Tp, class _Hash, class _Equal, class _Alloc>
2604typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2605__hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __first,
2606                                                const_iterator __last)
2607{
2608#if _LIBCPP_DEBUG_LEVEL >= 2
2609    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__first) == this,
2610        "unodered container::erase(iterator, iterator) called with an iterator not"
2611        " referring to this unodered container");
2612    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__last) == this,
2613        "unodered container::erase(iterator, iterator) called with an iterator not"
2614        " referring to this unodered container");
2615#endif
2616    for (const_iterator __p = __first; __first != __last; __p = __first)
2617    {
2618        ++__first;
2619        erase(__p);
2620    }
2621    __next_pointer __np = __last.__node_;
2622#if _LIBCPP_DEBUG_LEVEL >= 2
2623    return iterator (__np, this);
2624#else
2625    return iterator (__np);
2626#endif
2627}
2628
2629template <class _Tp, class _Hash, class _Equal, class _Alloc>
2630template <class _Key>
2631typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2632__hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_unique(const _Key& __k)
2633{
2634    iterator __i = find(__k);
2635    if (__i == end())
2636        return 0;
2637    erase(__i);
2638    return 1;
2639}
2640
2641template <class _Tp, class _Hash, class _Equal, class _Alloc>
2642template <class _Key>
2643typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2644__hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_multi(const _Key& __k)
2645{
2646    size_type __r = 0;
2647    iterator __i = find(__k);
2648    if (__i != end())
2649    {
2650        iterator __e = end();
2651        do
2652        {
2653            erase(__i++);
2654            ++__r;
2655        } while (__i != __e && key_eq()(*__i, __k));
2656    }
2657    return __r;
2658}
2659
2660template <class _Tp, class _Hash, class _Equal, class _Alloc>
2661typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2662__hash_table<_Tp, _Hash, _Equal, _Alloc>::remove(const_iterator __p) _NOEXCEPT
2663{
2664    // current node
2665    __next_pointer __cn = __p.__node_;
2666    size_type __bc = bucket_count();
2667    size_t __chash = __constrain_hash(__cn->__hash(), __bc);
2668    // find previous node
2669    __next_pointer __pn = __bucket_list_[__chash];
2670    for (; __pn->__next_ != __cn; __pn = __pn->__next_)
2671        ;
2672    // Fix up __bucket_list_
2673        // if __pn is not in same bucket (before begin is not in same bucket) &&
2674        //    if __cn->__next_ is not in same bucket (nullptr is not in same bucket)
2675    if (__pn == __p1_.first().__ptr()
2676            || __constrain_hash(__pn->__hash(), __bc) != __chash)
2677    {
2678        if (__cn->__next_ == nullptr
2679            || __constrain_hash(__cn->__next_->__hash(), __bc) != __chash)
2680            __bucket_list_[__chash] = nullptr;
2681    }
2682        // if __cn->__next_ is not in same bucket (nullptr is in same bucket)
2683    if (__cn->__next_ != nullptr)
2684    {
2685        size_t __nhash = __constrain_hash(__cn->__next_->__hash(), __bc);
2686        if (__nhash != __chash)
2687            __bucket_list_[__nhash] = __pn;
2688    }
2689    // remove __cn
2690    __pn->__next_ = __cn->__next_;
2691    __cn->__next_ = nullptr;
2692    --size();
2693#if _LIBCPP_DEBUG_LEVEL >= 2
2694    __c_node* __c = __get_db()->__find_c_and_lock(this);
2695    for (__i_node** __dp = __c->end_; __dp != __c->beg_; )
2696    {
2697        --__dp;
2698        iterator* __i = static_cast<iterator*>((*__dp)->__i_);
2699        if (__i->__node_ == __cn)
2700        {
2701            (*__dp)->__c_ = nullptr;
2702            if (--__c->end_ != __dp)
2703                memmove(__dp, __dp+1, (__c->end_ - __dp)*sizeof(__i_node*));
2704        }
2705    }
2706    __get_db()->unlock();
2707#endif
2708    return __node_holder(__cn->__upcast(), _Dp(__node_alloc(), true));
2709}
2710
2711template <class _Tp, class _Hash, class _Equal, class _Alloc>
2712template <class _Key>
2713inline
2714typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2715__hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_unique(const _Key& __k) const
2716{
2717    return static_cast<size_type>(find(__k) != end());
2718}
2719
2720template <class _Tp, class _Hash, class _Equal, class _Alloc>
2721template <class _Key>
2722typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2723__hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_multi(const _Key& __k) const
2724{
2725    size_type __r = 0;
2726    const_iterator __i = find(__k);
2727    if (__i != end())
2728    {
2729        const_iterator __e = end();
2730        do
2731        {
2732            ++__i;
2733            ++__r;
2734        } while (__i != __e && key_eq()(*__i, __k));
2735    }
2736    return __r;
2737}
2738
2739template <class _Tp, class _Hash, class _Equal, class _Alloc>
2740template <class _Key>
2741pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
2742     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
2743__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(
2744        const _Key& __k)
2745{
2746    iterator __i = find(__k);
2747    iterator __j = __i;
2748    if (__i != end())
2749        ++__j;
2750    return pair<iterator, iterator>(__i, __j);
2751}
2752
2753template <class _Tp, class _Hash, class _Equal, class _Alloc>
2754template <class _Key>
2755pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
2756     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
2757__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(
2758        const _Key& __k) const
2759{
2760    const_iterator __i = find(__k);
2761    const_iterator __j = __i;
2762    if (__i != end())
2763        ++__j;
2764    return pair<const_iterator, const_iterator>(__i, __j);
2765}
2766
2767template <class _Tp, class _Hash, class _Equal, class _Alloc>
2768template <class _Key>
2769pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
2770     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
2771__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(
2772        const _Key& __k)
2773{
2774    iterator __i = find(__k);
2775    iterator __j = __i;
2776    if (__i != end())
2777    {
2778        iterator __e = end();
2779        do
2780        {
2781            ++__j;
2782        } while (__j != __e && key_eq()(*__j, __k));
2783    }
2784    return pair<iterator, iterator>(__i, __j);
2785}
2786
2787template <class _Tp, class _Hash, class _Equal, class _Alloc>
2788template <class _Key>
2789pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
2790     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
2791__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(
2792        const _Key& __k) const
2793{
2794    const_iterator __i = find(__k);
2795    const_iterator __j = __i;
2796    if (__i != end())
2797    {
2798        const_iterator __e = end();
2799        do
2800        {
2801            ++__j;
2802        } while (__j != __e && key_eq()(*__j, __k));
2803    }
2804    return pair<const_iterator, const_iterator>(__i, __j);
2805}
2806
2807template <class _Tp, class _Hash, class _Equal, class _Alloc>
2808void
2809__hash_table<_Tp, _Hash, _Equal, _Alloc>::swap(__hash_table& __u)
2810#if _LIBCPP_STD_VER <= 11
2811    _NOEXCEPT_DEBUG_(
2812        __is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value
2813        && (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value
2814              || __is_nothrow_swappable<__pointer_allocator>::value)
2815        && (!__node_traits::propagate_on_container_swap::value
2816              || __is_nothrow_swappable<__node_allocator>::value)
2817            )
2818#else
2819  _NOEXCEPT_DEBUG_(__is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value)
2820#endif
2821{
2822    _LIBCPP_ASSERT(__node_traits::propagate_on_container_swap::value ||
2823                   this->__node_alloc() == __u.__node_alloc(),
2824                   "list::swap: Either propagate_on_container_swap must be true"
2825                   " or the allocators must compare equal");
2826    {
2827    __node_pointer_pointer __npp = __bucket_list_.release();
2828    __bucket_list_.reset(__u.__bucket_list_.release());
2829    __u.__bucket_list_.reset(__npp);
2830    }
2831    _VSTD::swap(__bucket_list_.get_deleter().size(), __u.__bucket_list_.get_deleter().size());
2832    __swap_allocator(__bucket_list_.get_deleter().__alloc(),
2833             __u.__bucket_list_.get_deleter().__alloc());
2834    __swap_allocator(__node_alloc(), __u.__node_alloc());
2835    _VSTD::swap(__p1_.first().__next_, __u.__p1_.first().__next_);
2836    __p2_.swap(__u.__p2_);
2837    __p3_.swap(__u.__p3_);
2838    if (size() > 0)
2839        __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
2840            __p1_.first().__ptr();
2841    if (__u.size() > 0)
2842        __u.__bucket_list_[__constrain_hash(__u.__p1_.first().__next_->__hash(), __u.bucket_count())] =
2843            __u.__p1_.first().__ptr();
2844#if _LIBCPP_DEBUG_LEVEL >= 2
2845    __get_db()->swap(this, &__u);
2846#endif
2847}
2848
2849template <class _Tp, class _Hash, class _Equal, class _Alloc>
2850typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2851__hash_table<_Tp, _Hash, _Equal, _Alloc>::bucket_size(size_type __n) const
2852{
2853    _LIBCPP_ASSERT(__n < bucket_count(),
2854        "unordered container::bucket_size(n) called with n >= bucket_count()");
2855    __next_pointer __np = __bucket_list_[__n];
2856    size_type __bc = bucket_count();
2857    size_type __r = 0;
2858    if (__np != nullptr)
2859    {
2860        for (__np = __np->__next_; __np != nullptr &&
2861                                   __constrain_hash(__np->__hash(), __bc) == __n;
2862                                                    __np = __np->__next_, ++__r)
2863            ;
2864    }
2865    return __r;
2866}
2867
2868template <class _Tp, class _Hash, class _Equal, class _Alloc>
2869inline _LIBCPP_INLINE_VISIBILITY
2870void
2871swap(__hash_table<_Tp, _Hash, _Equal, _Alloc>& __x,
2872     __hash_table<_Tp, _Hash, _Equal, _Alloc>& __y)
2873    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
2874{
2875    __x.swap(__y);
2876}
2877
2878#if _LIBCPP_DEBUG_LEVEL >= 2
2879
2880template <class _Tp, class _Hash, class _Equal, class _Alloc>
2881bool
2882__hash_table<_Tp, _Hash, _Equal, _Alloc>::__dereferenceable(const const_iterator* __i) const
2883{
2884    return __i->__node_ != nullptr;
2885}
2886
2887template <class _Tp, class _Hash, class _Equal, class _Alloc>
2888bool
2889__hash_table<_Tp, _Hash, _Equal, _Alloc>::__decrementable(const const_iterator*) const
2890{
2891    return false;
2892}
2893
2894template <class _Tp, class _Hash, class _Equal, class _Alloc>
2895bool
2896__hash_table<_Tp, _Hash, _Equal, _Alloc>::__addable(const const_iterator*, ptrdiff_t) const
2897{
2898    return false;
2899}
2900
2901template <class _Tp, class _Hash, class _Equal, class _Alloc>
2902bool
2903__hash_table<_Tp, _Hash, _Equal, _Alloc>::__subscriptable(const const_iterator*, ptrdiff_t) const
2904{
2905    return false;
2906}
2907
2908#endif  // _LIBCPP_DEBUG_LEVEL >= 2
2909
2910_LIBCPP_END_NAMESPACE_STD
2911
2912_LIBCPP_POP_MACROS
2913
2914#endif  // _LIBCPP__HASH_TABLE
2915