xref: /freebsd/contrib/llvm-project/libcxx/include/__hash_table (revision 0b57cec536236d46e3dba9bd041533462f33dbb7)
1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP__HASH_TABLE
11#define _LIBCPP__HASH_TABLE
12
13#include <__config>
14#include <initializer_list>
15#include <memory>
16#include <iterator>
17#include <algorithm>
18#include <cmath>
19#include <utility>
20#include <type_traits>
21
22#include <__debug>
23
24#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
25#pragma GCC system_header
26#endif
27
28_LIBCPP_PUSH_MACROS
29#include <__undef_macros>
30
31
32_LIBCPP_BEGIN_NAMESPACE_STD
33
34template <class _Key, class _Tp>
35struct __hash_value_type;
36
37#ifndef _LIBCPP_CXX03_LANG
38template <class _Tp>
39struct __is_hash_value_type_imp : false_type {};
40
41template <class _Key, class _Value>
42struct __is_hash_value_type_imp<__hash_value_type<_Key, _Value>> : true_type {};
43
44template <class ..._Args>
45struct __is_hash_value_type : false_type {};
46
47template <class _One>
48struct __is_hash_value_type<_One> : __is_hash_value_type_imp<typename __uncvref<_One>::type> {};
49#endif
50
51_LIBCPP_FUNC_VIS
52size_t __next_prime(size_t __n);
53
54template <class _NodePtr>
55struct __hash_node_base
56{
57    typedef typename pointer_traits<_NodePtr>::element_type __node_type;
58    typedef __hash_node_base __first_node;
59    typedef typename __rebind_pointer<_NodePtr, __first_node>::type __node_base_pointer;
60    typedef _NodePtr __node_pointer;
61
62#if defined(_LIBCPP_ABI_FIX_UNORDERED_NODE_POINTER_UB)
63  typedef __node_base_pointer __next_pointer;
64#else
65  typedef typename conditional<
66      is_pointer<__node_pointer>::value,
67      __node_base_pointer,
68      __node_pointer>::type   __next_pointer;
69#endif
70
71    __next_pointer    __next_;
72
73    _LIBCPP_INLINE_VISIBILITY
74    __next_pointer __ptr() _NOEXCEPT {
75        return static_cast<__next_pointer>(
76            pointer_traits<__node_base_pointer>::pointer_to(*this));
77    }
78
79    _LIBCPP_INLINE_VISIBILITY
80    __node_pointer __upcast() _NOEXCEPT {
81        return static_cast<__node_pointer>(
82            pointer_traits<__node_base_pointer>::pointer_to(*this));
83    }
84
85    _LIBCPP_INLINE_VISIBILITY
86    size_t __hash() const _NOEXCEPT {
87        return static_cast<__node_type const&>(*this).__hash_;
88    }
89
90    _LIBCPP_INLINE_VISIBILITY __hash_node_base() _NOEXCEPT : __next_(nullptr) {}
91};
92
93template <class _Tp, class _VoidPtr>
94struct __hash_node
95    : public __hash_node_base
96             <
97                 typename __rebind_pointer<_VoidPtr, __hash_node<_Tp, _VoidPtr> >::type
98             >
99{
100    typedef _Tp __node_value_type;
101
102    size_t            __hash_;
103    __node_value_type __value_;
104};
105
106inline _LIBCPP_INLINE_VISIBILITY
107bool
108__is_hash_power2(size_t __bc)
109{
110    return __bc > 2 && !(__bc & (__bc - 1));
111}
112
113inline _LIBCPP_INLINE_VISIBILITY
114size_t
115__constrain_hash(size_t __h, size_t __bc)
116{
117    return !(__bc & (__bc - 1)) ? __h & (__bc - 1) :
118        (__h < __bc ? __h : __h % __bc);
119}
120
121inline _LIBCPP_INLINE_VISIBILITY
122size_t
123__next_hash_pow2(size_t __n)
124{
125    return __n < 2 ? __n : (size_t(1) << (std::numeric_limits<size_t>::digits - __libcpp_clz(__n-1)));
126}
127
128
129template <class _Tp, class _Hash, class _Equal, class _Alloc> class __hash_table;
130
131template <class _NodePtr>      class _LIBCPP_TEMPLATE_VIS __hash_iterator;
132template <class _ConstNodePtr> class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
133template <class _NodePtr>      class _LIBCPP_TEMPLATE_VIS __hash_local_iterator;
134template <class _ConstNodePtr> class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
135template <class _HashIterator> class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
136template <class _HashIterator> class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
137
138template <class _Tp>
139struct __hash_key_value_types {
140  static_assert(!is_reference<_Tp>::value && !is_const<_Tp>::value, "");
141  typedef _Tp key_type;
142  typedef _Tp __node_value_type;
143  typedef _Tp __container_value_type;
144  static const bool __is_map = false;
145
146  _LIBCPP_INLINE_VISIBILITY
147  static key_type const& __get_key(_Tp const& __v) {
148    return __v;
149  }
150  _LIBCPP_INLINE_VISIBILITY
151  static __container_value_type const& __get_value(__node_value_type const& __v) {
152    return __v;
153  }
154  _LIBCPP_INLINE_VISIBILITY
155  static __container_value_type* __get_ptr(__node_value_type& __n) {
156    return _VSTD::addressof(__n);
157  }
158#ifndef _LIBCPP_CXX03_LANG
159  _LIBCPP_INLINE_VISIBILITY
160  static __container_value_type&& __move(__node_value_type& __v) {
161    return _VSTD::move(__v);
162  }
163#endif
164};
165
166template <class _Key, class _Tp>
167struct __hash_key_value_types<__hash_value_type<_Key, _Tp> > {
168  typedef _Key                                         key_type;
169  typedef _Tp                                          mapped_type;
170  typedef __hash_value_type<_Key, _Tp>                 __node_value_type;
171  typedef pair<const _Key, _Tp>                        __container_value_type;
172  typedef __container_value_type                       __map_value_type;
173  static const bool __is_map = true;
174
175  _LIBCPP_INLINE_VISIBILITY
176  static key_type const& __get_key(__container_value_type const& __v) {
177    return __v.first;
178  }
179
180  template <class _Up>
181  _LIBCPP_INLINE_VISIBILITY
182  static typename enable_if<__is_same_uncvref<_Up, __node_value_type>::value,
183      __container_value_type const&>::type
184  __get_value(_Up& __t) {
185    return __t.__get_value();
186  }
187
188  template <class _Up>
189  _LIBCPP_INLINE_VISIBILITY
190  static typename enable_if<__is_same_uncvref<_Up, __container_value_type>::value,
191      __container_value_type const&>::type
192  __get_value(_Up& __t) {
193    return __t;
194  }
195
196  _LIBCPP_INLINE_VISIBILITY
197  static __container_value_type* __get_ptr(__node_value_type& __n) {
198    return _VSTD::addressof(__n.__get_value());
199  }
200#ifndef _LIBCPP_CXX03_LANG
201  _LIBCPP_INLINE_VISIBILITY
202  static pair<key_type&&, mapped_type&&> __move(__node_value_type& __v) {
203    return __v.__move();
204  }
205#endif
206
207};
208
209template <class _Tp, class _AllocPtr, class _KVTypes = __hash_key_value_types<_Tp>,
210          bool = _KVTypes::__is_map>
211struct __hash_map_pointer_types {};
212
213template <class _Tp, class _AllocPtr, class _KVTypes>
214struct __hash_map_pointer_types<_Tp, _AllocPtr, _KVTypes, true> {
215  typedef typename _KVTypes::__map_value_type   _Mv;
216  typedef typename __rebind_pointer<_AllocPtr, _Mv>::type
217                                                       __map_value_type_pointer;
218  typedef typename __rebind_pointer<_AllocPtr, const _Mv>::type
219                                                 __const_map_value_type_pointer;
220};
221
222template <class _NodePtr, class _NodeT = typename pointer_traits<_NodePtr>::element_type>
223struct __hash_node_types;
224
225template <class _NodePtr, class _Tp, class _VoidPtr>
226struct __hash_node_types<_NodePtr, __hash_node<_Tp, _VoidPtr> >
227    : public __hash_key_value_types<_Tp>, __hash_map_pointer_types<_Tp, _VoidPtr>
228
229{
230  typedef __hash_key_value_types<_Tp>           __base;
231
232public:
233  typedef ptrdiff_t difference_type;
234  typedef size_t size_type;
235
236  typedef typename __rebind_pointer<_NodePtr, void>::type       __void_pointer;
237
238  typedef typename pointer_traits<_NodePtr>::element_type       __node_type;
239  typedef _NodePtr                                              __node_pointer;
240
241  typedef __hash_node_base<__node_pointer>                      __node_base_type;
242  typedef typename __rebind_pointer<_NodePtr, __node_base_type>::type
243                                                             __node_base_pointer;
244
245  typedef typename __node_base_type::__next_pointer          __next_pointer;
246
247  typedef _Tp                                                 __node_value_type;
248  typedef typename __rebind_pointer<_VoidPtr, __node_value_type>::type
249                                                      __node_value_type_pointer;
250  typedef typename __rebind_pointer<_VoidPtr, const __node_value_type>::type
251                                                __const_node_value_type_pointer;
252
253private:
254    static_assert(!is_const<__node_type>::value,
255                "_NodePtr should never be a pointer to const");
256    static_assert((is_same<typename pointer_traits<_VoidPtr>::element_type, void>::value),
257                  "_VoidPtr does not point to unqualified void type");
258    static_assert((is_same<typename __rebind_pointer<_VoidPtr, __node_type>::type,
259                          _NodePtr>::value), "_VoidPtr does not rebind to _NodePtr.");
260};
261
262template <class _HashIterator>
263struct __hash_node_types_from_iterator;
264template <class _NodePtr>
265struct __hash_node_types_from_iterator<__hash_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
266template <class _NodePtr>
267struct __hash_node_types_from_iterator<__hash_const_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
268template <class _NodePtr>
269struct __hash_node_types_from_iterator<__hash_local_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
270template <class _NodePtr>
271struct __hash_node_types_from_iterator<__hash_const_local_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
272
273
274template <class _NodeValueTp, class _VoidPtr>
275struct __make_hash_node_types {
276  typedef __hash_node<_NodeValueTp, _VoidPtr> _NodeTp;
277  typedef typename __rebind_pointer<_VoidPtr, _NodeTp>::type _NodePtr;
278  typedef __hash_node_types<_NodePtr> type;
279};
280
281template <class _NodePtr>
282class _LIBCPP_TEMPLATE_VIS __hash_iterator
283{
284    typedef __hash_node_types<_NodePtr> _NodeTypes;
285    typedef _NodePtr                            __node_pointer;
286    typedef typename _NodeTypes::__next_pointer __next_pointer;
287
288    __next_pointer            __node_;
289
290public:
291    typedef forward_iterator_tag                           iterator_category;
292    typedef typename _NodeTypes::__node_value_type         value_type;
293    typedef typename _NodeTypes::difference_type           difference_type;
294    typedef value_type&                                    reference;
295    typedef typename _NodeTypes::__node_value_type_pointer pointer;
296
297    _LIBCPP_INLINE_VISIBILITY __hash_iterator() _NOEXCEPT : __node_(nullptr) {
298        _LIBCPP_DEBUG_MODE(__get_db()->__insert_i(this));
299    }
300
301#if _LIBCPP_DEBUG_LEVEL >= 2
302    _LIBCPP_INLINE_VISIBILITY
303    __hash_iterator(const __hash_iterator& __i)
304        : __node_(__i.__node_)
305    {
306        __get_db()->__iterator_copy(this, &__i);
307    }
308
309    _LIBCPP_INLINE_VISIBILITY
310    ~__hash_iterator()
311    {
312        __get_db()->__erase_i(this);
313    }
314
315    _LIBCPP_INLINE_VISIBILITY
316    __hash_iterator& operator=(const __hash_iterator& __i)
317    {
318        if (this != &__i)
319        {
320            __get_db()->__iterator_copy(this, &__i);
321            __node_ = __i.__node_;
322        }
323        return *this;
324    }
325#endif  // _LIBCPP_DEBUG_LEVEL >= 2
326
327    _LIBCPP_INLINE_VISIBILITY
328    reference operator*() const {
329        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
330                             "Attempted to dereference a non-dereferenceable unordered container iterator");
331        return __node_->__upcast()->__value_;
332    }
333
334    _LIBCPP_INLINE_VISIBILITY
335    pointer operator->() const {
336        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
337                           "Attempted to dereference a non-dereferenceable unordered container iterator");
338        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
339    }
340
341    _LIBCPP_INLINE_VISIBILITY
342    __hash_iterator& operator++() {
343        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
344                       "Attempted to increment non-incrementable unordered container iterator");
345        __node_ = __node_->__next_;
346        return *this;
347    }
348
349    _LIBCPP_INLINE_VISIBILITY
350    __hash_iterator operator++(int)
351    {
352        __hash_iterator __t(*this);
353        ++(*this);
354        return __t;
355    }
356
357    friend _LIBCPP_INLINE_VISIBILITY
358    bool operator==(const __hash_iterator& __x, const __hash_iterator& __y)
359    {
360        return __x.__node_ == __y.__node_;
361    }
362    friend _LIBCPP_INLINE_VISIBILITY
363    bool operator!=(const __hash_iterator& __x, const __hash_iterator& __y)
364        {return !(__x == __y);}
365
366private:
367#if _LIBCPP_DEBUG_LEVEL >= 2
368    _LIBCPP_INLINE_VISIBILITY
369    __hash_iterator(__next_pointer __node, const void* __c) _NOEXCEPT
370        : __node_(__node)
371        {
372            __get_db()->__insert_ic(this, __c);
373        }
374#else
375    _LIBCPP_INLINE_VISIBILITY
376    __hash_iterator(__next_pointer __node) _NOEXCEPT
377        : __node_(__node)
378        {}
379#endif
380    template <class, class, class, class> friend class __hash_table;
381    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
382    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
383    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
384    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
385};
386
387template <class _NodePtr>
388class _LIBCPP_TEMPLATE_VIS __hash_const_iterator
389{
390    static_assert(!is_const<typename pointer_traits<_NodePtr>::element_type>::value, "");
391    typedef __hash_node_types<_NodePtr> _NodeTypes;
392    typedef _NodePtr                            __node_pointer;
393    typedef typename _NodeTypes::__next_pointer __next_pointer;
394
395    __next_pointer __node_;
396
397public:
398    typedef __hash_iterator<_NodePtr> __non_const_iterator;
399
400    typedef forward_iterator_tag                                 iterator_category;
401    typedef typename _NodeTypes::__node_value_type               value_type;
402    typedef typename _NodeTypes::difference_type                 difference_type;
403    typedef const value_type&                                    reference;
404    typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
405
406
407    _LIBCPP_INLINE_VISIBILITY __hash_const_iterator() _NOEXCEPT : __node_(nullptr) {
408        _LIBCPP_DEBUG_MODE(__get_db()->__insert_i(this));
409    }
410
411    _LIBCPP_INLINE_VISIBILITY
412    __hash_const_iterator(const __non_const_iterator& __x) _NOEXCEPT
413        : __node_(__x.__node_)
414    {
415        _LIBCPP_DEBUG_MODE(__get_db()->__iterator_copy(this, &__x));
416    }
417
418#if _LIBCPP_DEBUG_LEVEL >= 2
419    _LIBCPP_INLINE_VISIBILITY
420    __hash_const_iterator(const __hash_const_iterator& __i)
421        : __node_(__i.__node_)
422    {
423        __get_db()->__iterator_copy(this, &__i);
424    }
425
426    _LIBCPP_INLINE_VISIBILITY
427    ~__hash_const_iterator()
428    {
429        __get_db()->__erase_i(this);
430    }
431
432    _LIBCPP_INLINE_VISIBILITY
433    __hash_const_iterator& operator=(const __hash_const_iterator& __i)
434    {
435        if (this != &__i)
436        {
437            __get_db()->__iterator_copy(this, &__i);
438            __node_ = __i.__node_;
439        }
440        return *this;
441    }
442#endif  // _LIBCPP_DEBUG_LEVEL >= 2
443
444    _LIBCPP_INLINE_VISIBILITY
445    reference operator*() const {
446        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
447                           "Attempted to dereference a non-dereferenceable unordered container const_iterator");
448        return __node_->__upcast()->__value_;
449    }
450    _LIBCPP_INLINE_VISIBILITY
451    pointer operator->() const {
452        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
453                           "Attempted to dereference a non-dereferenceable unordered container const_iterator");
454        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
455    }
456
457    _LIBCPP_INLINE_VISIBILITY
458    __hash_const_iterator& operator++() {
459        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
460                             "Attempted to increment non-incrementable unordered container const_iterator");
461        __node_ = __node_->__next_;
462        return *this;
463    }
464
465    _LIBCPP_INLINE_VISIBILITY
466    __hash_const_iterator operator++(int)
467    {
468        __hash_const_iterator __t(*this);
469        ++(*this);
470        return __t;
471    }
472
473    friend _LIBCPP_INLINE_VISIBILITY
474    bool operator==(const __hash_const_iterator& __x, const __hash_const_iterator& __y)
475    {
476        return __x.__node_ == __y.__node_;
477    }
478    friend _LIBCPP_INLINE_VISIBILITY
479    bool operator!=(const __hash_const_iterator& __x, const __hash_const_iterator& __y)
480        {return !(__x == __y);}
481
482private:
483#if _LIBCPP_DEBUG_LEVEL >= 2
484    _LIBCPP_INLINE_VISIBILITY
485    __hash_const_iterator(__next_pointer __node, const void* __c) _NOEXCEPT
486        : __node_(__node)
487        {
488            __get_db()->__insert_ic(this, __c);
489        }
490#else
491    _LIBCPP_INLINE_VISIBILITY
492    __hash_const_iterator(__next_pointer __node) _NOEXCEPT
493        : __node_(__node)
494        {}
495#endif
496    template <class, class, class, class> friend class __hash_table;
497    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
498    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
499    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
500};
501
502template <class _NodePtr>
503class _LIBCPP_TEMPLATE_VIS __hash_local_iterator
504{
505    typedef __hash_node_types<_NodePtr> _NodeTypes;
506    typedef _NodePtr                            __node_pointer;
507    typedef typename _NodeTypes::__next_pointer __next_pointer;
508
509    __next_pointer         __node_;
510    size_t                 __bucket_;
511    size_t                 __bucket_count_;
512
513public:
514    typedef forward_iterator_tag                                iterator_category;
515    typedef typename _NodeTypes::__node_value_type              value_type;
516    typedef typename _NodeTypes::difference_type                difference_type;
517    typedef value_type&                                         reference;
518    typedef typename _NodeTypes::__node_value_type_pointer      pointer;
519
520    _LIBCPP_INLINE_VISIBILITY __hash_local_iterator() _NOEXCEPT : __node_(nullptr) {
521        _LIBCPP_DEBUG_MODE(__get_db()->__insert_i(this));
522    }
523
524#if _LIBCPP_DEBUG_LEVEL >= 2
525    _LIBCPP_INLINE_VISIBILITY
526    __hash_local_iterator(const __hash_local_iterator& __i)
527        : __node_(__i.__node_),
528          __bucket_(__i.__bucket_),
529          __bucket_count_(__i.__bucket_count_)
530    {
531        __get_db()->__iterator_copy(this, &__i);
532    }
533
534    _LIBCPP_INLINE_VISIBILITY
535    ~__hash_local_iterator()
536    {
537        __get_db()->__erase_i(this);
538    }
539
540    _LIBCPP_INLINE_VISIBILITY
541    __hash_local_iterator& operator=(const __hash_local_iterator& __i)
542    {
543        if (this != &__i)
544        {
545            __get_db()->__iterator_copy(this, &__i);
546            __node_ = __i.__node_;
547            __bucket_ = __i.__bucket_;
548            __bucket_count_ = __i.__bucket_count_;
549        }
550        return *this;
551    }
552#endif  // _LIBCPP_DEBUG_LEVEL >= 2
553
554    _LIBCPP_INLINE_VISIBILITY
555    reference operator*() const {
556        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
557                           "Attempted to dereference a non-dereferenceable unordered container local_iterator");
558        return __node_->__upcast()->__value_;
559    }
560
561    _LIBCPP_INLINE_VISIBILITY
562    pointer operator->() const {
563        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
564                             "Attempted to dereference a non-dereferenceable unordered container local_iterator");
565        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
566    }
567
568    _LIBCPP_INLINE_VISIBILITY
569    __hash_local_iterator& operator++() {
570        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
571                       "Attempted to increment non-incrementable unordered container local_iterator");
572        __node_ = __node_->__next_;
573        if (__node_ != nullptr && __constrain_hash(__node_->__hash(), __bucket_count_) != __bucket_)
574            __node_ = nullptr;
575        return *this;
576    }
577
578    _LIBCPP_INLINE_VISIBILITY
579    __hash_local_iterator operator++(int)
580    {
581        __hash_local_iterator __t(*this);
582        ++(*this);
583        return __t;
584    }
585
586    friend _LIBCPP_INLINE_VISIBILITY
587    bool operator==(const __hash_local_iterator& __x, const __hash_local_iterator& __y)
588    {
589        return __x.__node_ == __y.__node_;
590    }
591    friend _LIBCPP_INLINE_VISIBILITY
592    bool operator!=(const __hash_local_iterator& __x, const __hash_local_iterator& __y)
593        {return !(__x == __y);}
594
595private:
596#if _LIBCPP_DEBUG_LEVEL >= 2
597    _LIBCPP_INLINE_VISIBILITY
598    __hash_local_iterator(__next_pointer __node, size_t __bucket,
599                          size_t __bucket_count, const void* __c) _NOEXCEPT
600        : __node_(__node),
601          __bucket_(__bucket),
602          __bucket_count_(__bucket_count)
603        {
604            __get_db()->__insert_ic(this, __c);
605            if (__node_ != nullptr)
606                __node_ = __node_->__next_;
607        }
608#else
609    _LIBCPP_INLINE_VISIBILITY
610    __hash_local_iterator(__next_pointer __node, size_t __bucket,
611                          size_t __bucket_count) _NOEXCEPT
612        : __node_(__node),
613          __bucket_(__bucket),
614          __bucket_count_(__bucket_count)
615        {
616            if (__node_ != nullptr)
617                __node_ = __node_->__next_;
618        }
619#endif
620    template <class, class, class, class> friend class __hash_table;
621    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
622    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
623};
624
625template <class _ConstNodePtr>
626class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator
627{
628    typedef __hash_node_types<_ConstNodePtr> _NodeTypes;
629    typedef _ConstNodePtr                       __node_pointer;
630    typedef typename _NodeTypes::__next_pointer __next_pointer;
631
632    __next_pointer         __node_;
633    size_t                 __bucket_;
634    size_t                 __bucket_count_;
635
636    typedef pointer_traits<__node_pointer>          __pointer_traits;
637    typedef typename __pointer_traits::element_type __node;
638    typedef typename remove_const<__node>::type     __non_const_node;
639    typedef typename __rebind_pointer<__node_pointer, __non_const_node>::type
640        __non_const_node_pointer;
641public:
642    typedef __hash_local_iterator<__non_const_node_pointer>
643                                                    __non_const_iterator;
644
645    typedef forward_iterator_tag                                 iterator_category;
646    typedef typename _NodeTypes::__node_value_type               value_type;
647    typedef typename _NodeTypes::difference_type                 difference_type;
648    typedef const value_type&                                    reference;
649    typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
650
651
652    _LIBCPP_INLINE_VISIBILITY __hash_const_local_iterator() _NOEXCEPT : __node_(nullptr) {
653        _LIBCPP_DEBUG_MODE(__get_db()->__insert_i(this));
654    }
655
656    _LIBCPP_INLINE_VISIBILITY
657    __hash_const_local_iterator(const __non_const_iterator& __x) _NOEXCEPT
658        : __node_(__x.__node_),
659          __bucket_(__x.__bucket_),
660          __bucket_count_(__x.__bucket_count_)
661    {
662        _LIBCPP_DEBUG_MODE(__get_db()->__iterator_copy(this, &__x));
663    }
664
665#if _LIBCPP_DEBUG_LEVEL >= 2
666    _LIBCPP_INLINE_VISIBILITY
667    __hash_const_local_iterator(const __hash_const_local_iterator& __i)
668        : __node_(__i.__node_),
669          __bucket_(__i.__bucket_),
670          __bucket_count_(__i.__bucket_count_)
671    {
672        __get_db()->__iterator_copy(this, &__i);
673    }
674
675    _LIBCPP_INLINE_VISIBILITY
676    ~__hash_const_local_iterator()
677    {
678        __get_db()->__erase_i(this);
679    }
680
681    _LIBCPP_INLINE_VISIBILITY
682    __hash_const_local_iterator& operator=(const __hash_const_local_iterator& __i)
683    {
684        if (this != &__i)
685        {
686            __get_db()->__iterator_copy(this, &__i);
687            __node_ = __i.__node_;
688            __bucket_ = __i.__bucket_;
689            __bucket_count_ = __i.__bucket_count_;
690        }
691        return *this;
692    }
693#endif  // _LIBCPP_DEBUG_LEVEL >= 2
694
695    _LIBCPP_INLINE_VISIBILITY
696    reference operator*() const {
697        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
698                           "Attempted to dereference a non-dereferenceable unordered container const_local_iterator");
699        return __node_->__upcast()->__value_;
700    }
701
702    _LIBCPP_INLINE_VISIBILITY
703    pointer operator->() const {
704        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
705                           "Attempted to dereference a non-dereferenceable unordered container const_local_iterator");
706        return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__value_);
707    }
708
709    _LIBCPP_INLINE_VISIBILITY
710    __hash_const_local_iterator& operator++() {
711        _LIBCPP_DEBUG_ASSERT(__get_const_db()->__dereferenceable(this),
712                       "Attempted to increment non-incrementable unordered container const_local_iterator");
713        __node_ = __node_->__next_;
714        if (__node_ != nullptr && __constrain_hash(__node_->__hash(), __bucket_count_) != __bucket_)
715            __node_ = nullptr;
716        return *this;
717    }
718
719    _LIBCPP_INLINE_VISIBILITY
720    __hash_const_local_iterator operator++(int)
721    {
722        __hash_const_local_iterator __t(*this);
723        ++(*this);
724        return __t;
725    }
726
727    friend _LIBCPP_INLINE_VISIBILITY
728    bool operator==(const __hash_const_local_iterator& __x, const __hash_const_local_iterator& __y)
729    {
730        return __x.__node_ == __y.__node_;
731    }
732    friend _LIBCPP_INLINE_VISIBILITY
733    bool operator!=(const __hash_const_local_iterator& __x, const __hash_const_local_iterator& __y)
734        {return !(__x == __y);}
735
736private:
737#if _LIBCPP_DEBUG_LEVEL >= 2
738    _LIBCPP_INLINE_VISIBILITY
739    __hash_const_local_iterator(__next_pointer __node, size_t __bucket,
740                                size_t __bucket_count, const void* __c) _NOEXCEPT
741        : __node_(__node),
742          __bucket_(__bucket),
743          __bucket_count_(__bucket_count)
744        {
745            __get_db()->__insert_ic(this, __c);
746            if (__node_ != nullptr)
747                __node_ = __node_->__next_;
748        }
749#else
750    _LIBCPP_INLINE_VISIBILITY
751    __hash_const_local_iterator(__next_pointer __node, size_t __bucket,
752                                size_t __bucket_count) _NOEXCEPT
753        : __node_(__node),
754          __bucket_(__bucket),
755          __bucket_count_(__bucket_count)
756        {
757            if (__node_ != nullptr)
758                __node_ = __node_->__next_;
759        }
760#endif
761    template <class, class, class, class> friend class __hash_table;
762    template <class> friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
763};
764
765template <class _Alloc>
766class __bucket_list_deallocator
767{
768    typedef _Alloc                                          allocator_type;
769    typedef allocator_traits<allocator_type>                __alloc_traits;
770    typedef typename __alloc_traits::size_type              size_type;
771
772    __compressed_pair<size_type, allocator_type> __data_;
773public:
774    typedef typename __alloc_traits::pointer pointer;
775
776    _LIBCPP_INLINE_VISIBILITY
777    __bucket_list_deallocator()
778        _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
779        : __data_(0) {}
780
781    _LIBCPP_INLINE_VISIBILITY
782    __bucket_list_deallocator(const allocator_type& __a, size_type __size)
783        _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
784        : __data_(__size, __a) {}
785
786#ifndef _LIBCPP_CXX03_LANG
787    _LIBCPP_INLINE_VISIBILITY
788    __bucket_list_deallocator(__bucket_list_deallocator&& __x)
789        _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
790        : __data_(_VSTD::move(__x.__data_))
791    {
792        __x.size() = 0;
793    }
794#endif
795
796    _LIBCPP_INLINE_VISIBILITY
797    size_type& size() _NOEXCEPT {return __data_.first();}
798    _LIBCPP_INLINE_VISIBILITY
799    size_type  size() const _NOEXCEPT {return __data_.first();}
800
801    _LIBCPP_INLINE_VISIBILITY
802    allocator_type& __alloc() _NOEXCEPT {return __data_.second();}
803    _LIBCPP_INLINE_VISIBILITY
804    const allocator_type& __alloc() const _NOEXCEPT {return __data_.second();}
805
806    _LIBCPP_INLINE_VISIBILITY
807    void operator()(pointer __p) _NOEXCEPT
808    {
809        __alloc_traits::deallocate(__alloc(), __p, size());
810    }
811};
812
813template <class _Alloc> class __hash_map_node_destructor;
814
815template <class _Alloc>
816class __hash_node_destructor
817{
818    typedef _Alloc                                          allocator_type;
819    typedef allocator_traits<allocator_type>                __alloc_traits;
820
821public:
822    typedef typename __alloc_traits::pointer                pointer;
823private:
824    typedef __hash_node_types<pointer> _NodeTypes;
825
826    allocator_type& __na_;
827
828    __hash_node_destructor& operator=(const __hash_node_destructor&);
829
830public:
831    bool __value_constructed;
832
833    _LIBCPP_INLINE_VISIBILITY
834    explicit __hash_node_destructor(allocator_type& __na,
835                                    bool __constructed = false) _NOEXCEPT
836        : __na_(__na),
837          __value_constructed(__constructed)
838        {}
839
840    _LIBCPP_INLINE_VISIBILITY
841    void operator()(pointer __p) _NOEXCEPT
842    {
843        if (__value_constructed)
844            __alloc_traits::destroy(__na_, _NodeTypes::__get_ptr(__p->__value_));
845        if (__p)
846            __alloc_traits::deallocate(__na_, __p, 1);
847    }
848
849    template <class> friend class __hash_map_node_destructor;
850};
851
852#if _LIBCPP_STD_VER > 14
853template <class _NodeType, class _Alloc>
854struct __generic_container_node_destructor;
855
856template <class _Tp, class _VoidPtr, class _Alloc>
857struct __generic_container_node_destructor<__hash_node<_Tp, _VoidPtr>, _Alloc>
858    : __hash_node_destructor<_Alloc>
859{
860    using __hash_node_destructor<_Alloc>::__hash_node_destructor;
861};
862#endif
863
864template <class _Key, class _Hash, class _Equal>
865struct __enforce_unordered_container_requirements {
866#ifndef _LIBCPP_CXX03_LANG
867    static_assert(__check_hash_requirements<_Key, _Hash>::value,
868    "the specified hash does not meet the Hash requirements");
869    static_assert(is_copy_constructible<_Equal>::value,
870    "the specified comparator is required to be copy constructible");
871#endif
872    typedef int type;
873};
874
875template <class _Key, class _Hash, class _Equal>
876#ifndef _LIBCPP_CXX03_LANG
877    _LIBCPP_DIAGNOSE_WARNING(!__invokable<_Equal const&, _Key const&, _Key const&>::value,
878    "the specified comparator type does not provide a viable const call operator")
879    _LIBCPP_DIAGNOSE_WARNING(!__invokable<_Hash const&, _Key const&>::value,
880    "the specified hash functor does not provide a viable const call operator")
881#endif
882typename __enforce_unordered_container_requirements<_Key, _Hash, _Equal>::type
883__diagnose_unordered_container_requirements(int);
884
885// This dummy overload is used so that the compiler won't emit a spurious
886// "no matching function for call to __diagnose_unordered_xxx" diagnostic
887// when the overload above causes a hard error.
888template <class _Key, class _Hash, class _Equal>
889int __diagnose_unordered_container_requirements(void*);
890
891template <class _Tp, class _Hash, class _Equal, class _Alloc>
892class __hash_table
893{
894public:
895    typedef _Tp    value_type;
896    typedef _Hash  hasher;
897    typedef _Equal key_equal;
898    typedef _Alloc allocator_type;
899
900private:
901    typedef allocator_traits<allocator_type> __alloc_traits;
902    typedef typename
903      __make_hash_node_types<value_type, typename __alloc_traits::void_pointer>::type
904                                                                     _NodeTypes;
905public:
906
907    typedef typename _NodeTypes::__node_value_type           __node_value_type;
908    typedef typename _NodeTypes::__container_value_type      __container_value_type;
909    typedef typename _NodeTypes::key_type                    key_type;
910    typedef value_type&                              reference;
911    typedef const value_type&                        const_reference;
912    typedef typename __alloc_traits::pointer         pointer;
913    typedef typename __alloc_traits::const_pointer   const_pointer;
914#ifndef _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
915    typedef typename __alloc_traits::size_type       size_type;
916#else
917    typedef typename _NodeTypes::size_type           size_type;
918#endif
919    typedef typename _NodeTypes::difference_type     difference_type;
920public:
921    // Create __node
922
923    typedef typename _NodeTypes::__node_type __node;
924    typedef typename __rebind_alloc_helper<__alloc_traits, __node>::type __node_allocator;
925    typedef allocator_traits<__node_allocator>       __node_traits;
926    typedef typename _NodeTypes::__void_pointer      __void_pointer;
927    typedef typename _NodeTypes::__node_pointer      __node_pointer;
928    typedef typename _NodeTypes::__node_pointer      __node_const_pointer;
929    typedef typename _NodeTypes::__node_base_type    __first_node;
930    typedef typename _NodeTypes::__node_base_pointer __node_base_pointer;
931    typedef typename _NodeTypes::__next_pointer      __next_pointer;
932
933private:
934    // check for sane allocator pointer rebinding semantics. Rebinding the
935    // allocator for a new pointer type should be exactly the same as rebinding
936    // the pointer using 'pointer_traits'.
937    static_assert((is_same<__node_pointer, typename __node_traits::pointer>::value),
938                  "Allocator does not rebind pointers in a sane manner.");
939    typedef typename __rebind_alloc_helper<__node_traits, __first_node>::type
940        __node_base_allocator;
941    typedef allocator_traits<__node_base_allocator> __node_base_traits;
942    static_assert((is_same<__node_base_pointer, typename __node_base_traits::pointer>::value),
943                 "Allocator does not rebind pointers in a sane manner.");
944
945private:
946
947    typedef typename __rebind_alloc_helper<__node_traits, __next_pointer>::type __pointer_allocator;
948    typedef __bucket_list_deallocator<__pointer_allocator> __bucket_list_deleter;
949    typedef unique_ptr<__next_pointer[], __bucket_list_deleter> __bucket_list;
950    typedef allocator_traits<__pointer_allocator>          __pointer_alloc_traits;
951    typedef typename __bucket_list_deleter::pointer       __node_pointer_pointer;
952
953    // --- Member data begin ---
954    __bucket_list                                         __bucket_list_;
955    __compressed_pair<__first_node, __node_allocator>     __p1_;
956    __compressed_pair<size_type, hasher>                  __p2_;
957    __compressed_pair<float, key_equal>                   __p3_;
958    // --- Member data end ---
959
960    _LIBCPP_INLINE_VISIBILITY
961    size_type& size() _NOEXCEPT {return __p2_.first();}
962public:
963    _LIBCPP_INLINE_VISIBILITY
964    size_type  size() const _NOEXCEPT {return __p2_.first();}
965
966    _LIBCPP_INLINE_VISIBILITY
967    hasher& hash_function() _NOEXCEPT {return __p2_.second();}
968    _LIBCPP_INLINE_VISIBILITY
969    const hasher& hash_function() const _NOEXCEPT {return __p2_.second();}
970
971    _LIBCPP_INLINE_VISIBILITY
972    float& max_load_factor() _NOEXCEPT {return __p3_.first();}
973    _LIBCPP_INLINE_VISIBILITY
974    float  max_load_factor() const _NOEXCEPT {return __p3_.first();}
975
976    _LIBCPP_INLINE_VISIBILITY
977    key_equal& key_eq() _NOEXCEPT {return __p3_.second();}
978    _LIBCPP_INLINE_VISIBILITY
979    const key_equal& key_eq() const _NOEXCEPT {return __p3_.second();}
980
981    _LIBCPP_INLINE_VISIBILITY
982    __node_allocator& __node_alloc() _NOEXCEPT {return __p1_.second();}
983    _LIBCPP_INLINE_VISIBILITY
984    const __node_allocator& __node_alloc() const _NOEXCEPT
985        {return __p1_.second();}
986
987public:
988    typedef __hash_iterator<__node_pointer>                   iterator;
989    typedef __hash_const_iterator<__node_pointer>             const_iterator;
990    typedef __hash_local_iterator<__node_pointer>             local_iterator;
991    typedef __hash_const_local_iterator<__node_pointer>       const_local_iterator;
992
993    _LIBCPP_INLINE_VISIBILITY
994    __hash_table()
995        _NOEXCEPT_(
996            is_nothrow_default_constructible<__bucket_list>::value &&
997            is_nothrow_default_constructible<__first_node>::value &&
998            is_nothrow_default_constructible<__node_allocator>::value &&
999            is_nothrow_default_constructible<hasher>::value &&
1000            is_nothrow_default_constructible<key_equal>::value);
1001    _LIBCPP_INLINE_VISIBILITY
1002    __hash_table(const hasher& __hf, const key_equal& __eql);
1003    __hash_table(const hasher& __hf, const key_equal& __eql,
1004                 const allocator_type& __a);
1005    explicit __hash_table(const allocator_type& __a);
1006    __hash_table(const __hash_table& __u);
1007    __hash_table(const __hash_table& __u, const allocator_type& __a);
1008#ifndef _LIBCPP_CXX03_LANG
1009    __hash_table(__hash_table&& __u)
1010        _NOEXCEPT_(
1011            is_nothrow_move_constructible<__bucket_list>::value &&
1012            is_nothrow_move_constructible<__first_node>::value &&
1013            is_nothrow_move_constructible<__node_allocator>::value &&
1014            is_nothrow_move_constructible<hasher>::value &&
1015            is_nothrow_move_constructible<key_equal>::value);
1016    __hash_table(__hash_table&& __u, const allocator_type& __a);
1017#endif  // _LIBCPP_CXX03_LANG
1018    ~__hash_table();
1019
1020    __hash_table& operator=(const __hash_table& __u);
1021#ifndef _LIBCPP_CXX03_LANG
1022    _LIBCPP_INLINE_VISIBILITY
1023    __hash_table& operator=(__hash_table&& __u)
1024        _NOEXCEPT_(
1025            __node_traits::propagate_on_container_move_assignment::value &&
1026            is_nothrow_move_assignable<__node_allocator>::value &&
1027            is_nothrow_move_assignable<hasher>::value &&
1028            is_nothrow_move_assignable<key_equal>::value);
1029#endif
1030    template <class _InputIterator>
1031        void __assign_unique(_InputIterator __first, _InputIterator __last);
1032    template <class _InputIterator>
1033        void __assign_multi(_InputIterator __first, _InputIterator __last);
1034
1035    _LIBCPP_INLINE_VISIBILITY
1036    size_type max_size() const _NOEXCEPT
1037    {
1038        return std::min<size_type>(
1039            __node_traits::max_size(__node_alloc()),
1040            numeric_limits<difference_type >::max()
1041        );
1042    }
1043
1044private:
1045    _LIBCPP_INLINE_VISIBILITY
1046    __next_pointer __node_insert_multi_prepare(size_t __cp_hash,
1047                                               value_type& __cp_val);
1048    _LIBCPP_INLINE_VISIBILITY
1049    void __node_insert_multi_perform(__node_pointer __cp,
1050                                     __next_pointer __pn) _NOEXCEPT;
1051
1052    _LIBCPP_INLINE_VISIBILITY
1053    __next_pointer __node_insert_unique_prepare(size_t __nd_hash,
1054                                                value_type& __nd_val);
1055    _LIBCPP_INLINE_VISIBILITY
1056    void __node_insert_unique_perform(__node_pointer __ptr) _NOEXCEPT;
1057
1058public:
1059    _LIBCPP_INLINE_VISIBILITY
1060    pair<iterator, bool> __node_insert_unique(__node_pointer __nd);
1061    _LIBCPP_INLINE_VISIBILITY
1062    iterator             __node_insert_multi(__node_pointer __nd);
1063    _LIBCPP_INLINE_VISIBILITY
1064    iterator             __node_insert_multi(const_iterator __p,
1065                                             __node_pointer __nd);
1066
1067#ifndef _LIBCPP_CXX03_LANG
1068    template <class _Key, class ..._Args>
1069    _LIBCPP_INLINE_VISIBILITY
1070    pair<iterator, bool> __emplace_unique_key_args(_Key const& __k, _Args&&... __args);
1071
1072    template <class... _Args>
1073    _LIBCPP_INLINE_VISIBILITY
1074    pair<iterator, bool> __emplace_unique_impl(_Args&&... __args);
1075
1076    template <class _Pp>
1077    _LIBCPP_INLINE_VISIBILITY
1078    pair<iterator, bool> __emplace_unique(_Pp&& __x) {
1079      return __emplace_unique_extract_key(_VSTD::forward<_Pp>(__x),
1080                                          __can_extract_key<_Pp, key_type>());
1081    }
1082
1083    template <class _First, class _Second>
1084    _LIBCPP_INLINE_VISIBILITY
1085    typename enable_if<
1086        __can_extract_map_key<_First, key_type, __container_value_type>::value,
1087        pair<iterator, bool>
1088    >::type __emplace_unique(_First&& __f, _Second&& __s) {
1089        return __emplace_unique_key_args(__f, _VSTD::forward<_First>(__f),
1090                                              _VSTD::forward<_Second>(__s));
1091    }
1092
1093    template <class... _Args>
1094    _LIBCPP_INLINE_VISIBILITY
1095    pair<iterator, bool> __emplace_unique(_Args&&... __args) {
1096      return __emplace_unique_impl(_VSTD::forward<_Args>(__args)...);
1097    }
1098
1099    template <class _Pp>
1100    _LIBCPP_INLINE_VISIBILITY
1101    pair<iterator, bool>
1102    __emplace_unique_extract_key(_Pp&& __x, __extract_key_fail_tag) {
1103      return __emplace_unique_impl(_VSTD::forward<_Pp>(__x));
1104    }
1105    template <class _Pp>
1106    _LIBCPP_INLINE_VISIBILITY
1107    pair<iterator, bool>
1108    __emplace_unique_extract_key(_Pp&& __x, __extract_key_self_tag) {
1109      return __emplace_unique_key_args(__x, _VSTD::forward<_Pp>(__x));
1110    }
1111    template <class _Pp>
1112    _LIBCPP_INLINE_VISIBILITY
1113    pair<iterator, bool>
1114    __emplace_unique_extract_key(_Pp&& __x, __extract_key_first_tag) {
1115      return __emplace_unique_key_args(__x.first, _VSTD::forward<_Pp>(__x));
1116    }
1117
1118    template <class... _Args>
1119    _LIBCPP_INLINE_VISIBILITY
1120    iterator __emplace_multi(_Args&&... __args);
1121    template <class... _Args>
1122    _LIBCPP_INLINE_VISIBILITY
1123    iterator __emplace_hint_multi(const_iterator __p, _Args&&... __args);
1124
1125
1126    _LIBCPP_INLINE_VISIBILITY
1127    pair<iterator, bool>
1128    __insert_unique(__container_value_type&& __x) {
1129      return __emplace_unique_key_args(_NodeTypes::__get_key(__x), _VSTD::move(__x));
1130    }
1131
1132    template <class _Pp, class = typename enable_if<
1133            !__is_same_uncvref<_Pp, __container_value_type>::value
1134        >::type>
1135    _LIBCPP_INLINE_VISIBILITY
1136    pair<iterator, bool> __insert_unique(_Pp&& __x) {
1137      return __emplace_unique(_VSTD::forward<_Pp>(__x));
1138    }
1139
1140    template <class _Pp>
1141    _LIBCPP_INLINE_VISIBILITY
1142    iterator __insert_multi(_Pp&& __x) {
1143      return __emplace_multi(_VSTD::forward<_Pp>(__x));
1144    }
1145
1146    template <class _Pp>
1147    _LIBCPP_INLINE_VISIBILITY
1148    iterator __insert_multi(const_iterator __p, _Pp&& __x) {
1149        return __emplace_hint_multi(__p, _VSTD::forward<_Pp>(__x));
1150    }
1151
1152#else  // !defined(_LIBCPP_CXX03_LANG)
1153    template <class _Key, class _Args>
1154    _LIBCPP_INLINE_VISIBILITY
1155    pair<iterator, bool> __emplace_unique_key_args(_Key const&, _Args& __args);
1156
1157    iterator __insert_multi(const __container_value_type& __x);
1158    iterator __insert_multi(const_iterator __p, const __container_value_type& __x);
1159#endif
1160
1161    _LIBCPP_INLINE_VISIBILITY
1162    pair<iterator, bool> __insert_unique(const __container_value_type& __x) {
1163        return __emplace_unique_key_args(_NodeTypes::__get_key(__x), __x);
1164    }
1165
1166#if _LIBCPP_STD_VER > 14
1167    template <class _NodeHandle, class _InsertReturnType>
1168    _LIBCPP_INLINE_VISIBILITY
1169    _InsertReturnType __node_handle_insert_unique(_NodeHandle&& __nh);
1170    template <class _NodeHandle>
1171    _LIBCPP_INLINE_VISIBILITY
1172    iterator __node_handle_insert_unique(const_iterator __hint,
1173                                         _NodeHandle&& __nh);
1174    template <class _Table>
1175    _LIBCPP_INLINE_VISIBILITY
1176    void __node_handle_merge_unique(_Table& __source);
1177
1178    template <class _NodeHandle>
1179    _LIBCPP_INLINE_VISIBILITY
1180    iterator __node_handle_insert_multi(_NodeHandle&& __nh);
1181    template <class _NodeHandle>
1182    _LIBCPP_INLINE_VISIBILITY
1183    iterator __node_handle_insert_multi(const_iterator __hint, _NodeHandle&& __nh);
1184    template <class _Table>
1185    _LIBCPP_INLINE_VISIBILITY
1186    void __node_handle_merge_multi(_Table& __source);
1187
1188    template <class _NodeHandle>
1189    _LIBCPP_INLINE_VISIBILITY
1190    _NodeHandle __node_handle_extract(key_type const& __key);
1191    template <class _NodeHandle>
1192    _LIBCPP_INLINE_VISIBILITY
1193    _NodeHandle __node_handle_extract(const_iterator __it);
1194#endif
1195
1196    void clear() _NOEXCEPT;
1197    void rehash(size_type __n);
1198    _LIBCPP_INLINE_VISIBILITY void reserve(size_type __n)
1199        {rehash(static_cast<size_type>(ceil(__n / max_load_factor())));}
1200
1201    _LIBCPP_INLINE_VISIBILITY
1202    size_type bucket_count() const _NOEXCEPT
1203    {
1204        return __bucket_list_.get_deleter().size();
1205    }
1206
1207    _LIBCPP_INLINE_VISIBILITY
1208    iterator       begin() _NOEXCEPT;
1209    _LIBCPP_INLINE_VISIBILITY
1210    iterator       end() _NOEXCEPT;
1211    _LIBCPP_INLINE_VISIBILITY
1212    const_iterator begin() const _NOEXCEPT;
1213    _LIBCPP_INLINE_VISIBILITY
1214    const_iterator end() const _NOEXCEPT;
1215
1216    template <class _Key>
1217        _LIBCPP_INLINE_VISIBILITY
1218        size_type bucket(const _Key& __k) const
1219        {
1220            _LIBCPP_ASSERT(bucket_count() > 0,
1221                "unordered container::bucket(key) called when bucket_count() == 0");
1222            return __constrain_hash(hash_function()(__k), bucket_count());
1223        }
1224
1225    template <class _Key>
1226        iterator       find(const _Key& __x);
1227    template <class _Key>
1228        const_iterator find(const _Key& __x) const;
1229
1230    typedef __hash_node_destructor<__node_allocator> _Dp;
1231    typedef unique_ptr<__node, _Dp> __node_holder;
1232
1233    iterator erase(const_iterator __p);
1234    iterator erase(const_iterator __first, const_iterator __last);
1235    template <class _Key>
1236        size_type __erase_unique(const _Key& __k);
1237    template <class _Key>
1238        size_type __erase_multi(const _Key& __k);
1239    __node_holder remove(const_iterator __p) _NOEXCEPT;
1240
1241    template <class _Key>
1242        _LIBCPP_INLINE_VISIBILITY
1243        size_type __count_unique(const _Key& __k) const;
1244    template <class _Key>
1245        size_type __count_multi(const _Key& __k) const;
1246
1247    template <class _Key>
1248        pair<iterator, iterator>
1249        __equal_range_unique(const _Key& __k);
1250    template <class _Key>
1251        pair<const_iterator, const_iterator>
1252        __equal_range_unique(const _Key& __k) const;
1253
1254    template <class _Key>
1255        pair<iterator, iterator>
1256        __equal_range_multi(const _Key& __k);
1257    template <class _Key>
1258        pair<const_iterator, const_iterator>
1259        __equal_range_multi(const _Key& __k) const;
1260
1261    void swap(__hash_table& __u)
1262#if _LIBCPP_STD_VER <= 11
1263        _NOEXCEPT_(
1264            __is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value
1265            && (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value
1266                  || __is_nothrow_swappable<__pointer_allocator>::value)
1267            && (!__node_traits::propagate_on_container_swap::value
1268                  || __is_nothrow_swappable<__node_allocator>::value)
1269            );
1270#else
1271     _NOEXCEPT_(__is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value);
1272#endif
1273
1274    _LIBCPP_INLINE_VISIBILITY
1275    size_type max_bucket_count() const _NOEXCEPT
1276        {return max_size(); }
1277    size_type bucket_size(size_type __n) const;
1278    _LIBCPP_INLINE_VISIBILITY float load_factor() const _NOEXCEPT
1279    {
1280        size_type __bc = bucket_count();
1281        return __bc != 0 ? (float)size() / __bc : 0.f;
1282    }
1283    _LIBCPP_INLINE_VISIBILITY void max_load_factor(float __mlf) _NOEXCEPT
1284    {
1285        _LIBCPP_ASSERT(__mlf > 0,
1286            "unordered container::max_load_factor(lf) called with lf <= 0");
1287        max_load_factor() = _VSTD::max(__mlf, load_factor());
1288    }
1289
1290    _LIBCPP_INLINE_VISIBILITY
1291    local_iterator
1292    begin(size_type __n)
1293    {
1294        _LIBCPP_ASSERT(__n < bucket_count(),
1295            "unordered container::begin(n) called with n >= bucket_count()");
1296#if _LIBCPP_DEBUG_LEVEL >= 2
1297        return local_iterator(__bucket_list_[__n], __n, bucket_count(), this);
1298#else
1299        return local_iterator(__bucket_list_[__n], __n, bucket_count());
1300#endif
1301    }
1302
1303    _LIBCPP_INLINE_VISIBILITY
1304    local_iterator
1305    end(size_type __n)
1306    {
1307        _LIBCPP_ASSERT(__n < bucket_count(),
1308            "unordered container::end(n) called with n >= bucket_count()");
1309#if _LIBCPP_DEBUG_LEVEL >= 2
1310        return local_iterator(nullptr, __n, bucket_count(), this);
1311#else
1312        return local_iterator(nullptr, __n, bucket_count());
1313#endif
1314    }
1315
1316    _LIBCPP_INLINE_VISIBILITY
1317    const_local_iterator
1318    cbegin(size_type __n) const
1319    {
1320        _LIBCPP_ASSERT(__n < bucket_count(),
1321            "unordered container::cbegin(n) called with n >= bucket_count()");
1322#if _LIBCPP_DEBUG_LEVEL >= 2
1323        return const_local_iterator(__bucket_list_[__n], __n, bucket_count(), this);
1324#else
1325        return const_local_iterator(__bucket_list_[__n], __n, bucket_count());
1326#endif
1327    }
1328
1329    _LIBCPP_INLINE_VISIBILITY
1330    const_local_iterator
1331    cend(size_type __n) const
1332    {
1333        _LIBCPP_ASSERT(__n < bucket_count(),
1334            "unordered container::cend(n) called with n >= bucket_count()");
1335#if _LIBCPP_DEBUG_LEVEL >= 2
1336        return const_local_iterator(nullptr, __n, bucket_count(), this);
1337#else
1338        return const_local_iterator(nullptr, __n, bucket_count());
1339#endif
1340    }
1341
1342#if _LIBCPP_DEBUG_LEVEL >= 2
1343
1344    bool __dereferenceable(const const_iterator* __i) const;
1345    bool __decrementable(const const_iterator* __i) const;
1346    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
1347    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
1348
1349#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1350
1351private:
1352    void __rehash(size_type __n);
1353
1354#ifndef _LIBCPP_CXX03_LANG
1355    template <class ..._Args>
1356    __node_holder __construct_node(_Args&& ...__args);
1357
1358    template <class _First, class ..._Rest>
1359    __node_holder __construct_node_hash(size_t __hash, _First&& __f, _Rest&&... __rest);
1360#else // _LIBCPP_CXX03_LANG
1361    __node_holder __construct_node(const __container_value_type& __v);
1362    __node_holder __construct_node_hash(size_t __hash, const __container_value_type& __v);
1363#endif
1364
1365
1366    _LIBCPP_INLINE_VISIBILITY
1367    void __copy_assign_alloc(const __hash_table& __u)
1368        {__copy_assign_alloc(__u, integral_constant<bool,
1369             __node_traits::propagate_on_container_copy_assignment::value>());}
1370    void __copy_assign_alloc(const __hash_table& __u, true_type);
1371    _LIBCPP_INLINE_VISIBILITY
1372        void __copy_assign_alloc(const __hash_table&, false_type) {}
1373
1374#ifndef _LIBCPP_CXX03_LANG
1375    void __move_assign(__hash_table& __u, false_type);
1376    void __move_assign(__hash_table& __u, true_type)
1377        _NOEXCEPT_(
1378            is_nothrow_move_assignable<__node_allocator>::value &&
1379            is_nothrow_move_assignable<hasher>::value &&
1380            is_nothrow_move_assignable<key_equal>::value);
1381    _LIBCPP_INLINE_VISIBILITY
1382    void __move_assign_alloc(__hash_table& __u)
1383        _NOEXCEPT_(
1384            !__node_traits::propagate_on_container_move_assignment::value ||
1385            (is_nothrow_move_assignable<__pointer_allocator>::value &&
1386             is_nothrow_move_assignable<__node_allocator>::value))
1387        {__move_assign_alloc(__u, integral_constant<bool,
1388             __node_traits::propagate_on_container_move_assignment::value>());}
1389    _LIBCPP_INLINE_VISIBILITY
1390    void __move_assign_alloc(__hash_table& __u, true_type)
1391        _NOEXCEPT_(
1392            is_nothrow_move_assignable<__pointer_allocator>::value &&
1393            is_nothrow_move_assignable<__node_allocator>::value)
1394    {
1395        __bucket_list_.get_deleter().__alloc() =
1396                _VSTD::move(__u.__bucket_list_.get_deleter().__alloc());
1397        __node_alloc() = _VSTD::move(__u.__node_alloc());
1398    }
1399    _LIBCPP_INLINE_VISIBILITY
1400        void __move_assign_alloc(__hash_table&, false_type) _NOEXCEPT {}
1401#endif // _LIBCPP_CXX03_LANG
1402
1403    void __deallocate_node(__next_pointer __np) _NOEXCEPT;
1404    __next_pointer __detach() _NOEXCEPT;
1405
1406    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
1407    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
1408};
1409
1410template <class _Tp, class _Hash, class _Equal, class _Alloc>
1411inline
1412__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table()
1413    _NOEXCEPT_(
1414        is_nothrow_default_constructible<__bucket_list>::value &&
1415        is_nothrow_default_constructible<__first_node>::value &&
1416        is_nothrow_default_constructible<__node_allocator>::value &&
1417        is_nothrow_default_constructible<hasher>::value &&
1418        is_nothrow_default_constructible<key_equal>::value)
1419    : __p2_(0),
1420      __p3_(1.0f)
1421{
1422}
1423
1424template <class _Tp, class _Hash, class _Equal, class _Alloc>
1425inline
1426__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const hasher& __hf,
1427                                                       const key_equal& __eql)
1428    : __bucket_list_(nullptr, __bucket_list_deleter()),
1429      __p1_(),
1430      __p2_(0, __hf),
1431      __p3_(1.0f, __eql)
1432{
1433}
1434
1435template <class _Tp, class _Hash, class _Equal, class _Alloc>
1436__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const hasher& __hf,
1437                                                       const key_equal& __eql,
1438                                                       const allocator_type& __a)
1439    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1440      __p1_(__second_tag(), __node_allocator(__a)),
1441      __p2_(0, __hf),
1442      __p3_(1.0f, __eql)
1443{
1444}
1445
1446template <class _Tp, class _Hash, class _Equal, class _Alloc>
1447__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const allocator_type& __a)
1448    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1449      __p1_(__second_tag(), __node_allocator(__a)),
1450      __p2_(0),
1451      __p3_(1.0f)
1452{
1453}
1454
1455template <class _Tp, class _Hash, class _Equal, class _Alloc>
1456__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u)
1457    : __bucket_list_(nullptr,
1458          __bucket_list_deleter(allocator_traits<__pointer_allocator>::
1459              select_on_container_copy_construction(
1460                  __u.__bucket_list_.get_deleter().__alloc()), 0)),
1461      __p1_(__second_tag(), allocator_traits<__node_allocator>::
1462          select_on_container_copy_construction(__u.__node_alloc())),
1463      __p2_(0, __u.hash_function()),
1464      __p3_(__u.__p3_)
1465{
1466}
1467
1468template <class _Tp, class _Hash, class _Equal, class _Alloc>
1469__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u,
1470                                                       const allocator_type& __a)
1471    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1472      __p1_(__second_tag(), __node_allocator(__a)),
1473      __p2_(0, __u.hash_function()),
1474      __p3_(__u.__p3_)
1475{
1476}
1477
1478#ifndef _LIBCPP_CXX03_LANG
1479
1480template <class _Tp, class _Hash, class _Equal, class _Alloc>
1481__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u)
1482        _NOEXCEPT_(
1483            is_nothrow_move_constructible<__bucket_list>::value &&
1484            is_nothrow_move_constructible<__first_node>::value &&
1485            is_nothrow_move_constructible<__node_allocator>::value &&
1486            is_nothrow_move_constructible<hasher>::value &&
1487            is_nothrow_move_constructible<key_equal>::value)
1488    : __bucket_list_(_VSTD::move(__u.__bucket_list_)),
1489      __p1_(_VSTD::move(__u.__p1_)),
1490      __p2_(_VSTD::move(__u.__p2_)),
1491      __p3_(_VSTD::move(__u.__p3_))
1492{
1493    if (size() > 0)
1494    {
1495        __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
1496            __p1_.first().__ptr();
1497        __u.__p1_.first().__next_ = nullptr;
1498        __u.size() = 0;
1499    }
1500}
1501
1502template <class _Tp, class _Hash, class _Equal, class _Alloc>
1503__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u,
1504                                                       const allocator_type& __a)
1505    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1506      __p1_(__second_tag(), __node_allocator(__a)),
1507      __p2_(0, _VSTD::move(__u.hash_function())),
1508      __p3_(_VSTD::move(__u.__p3_))
1509{
1510    if (__a == allocator_type(__u.__node_alloc()))
1511    {
1512        __bucket_list_.reset(__u.__bucket_list_.release());
1513        __bucket_list_.get_deleter().size() = __u.__bucket_list_.get_deleter().size();
1514        __u.__bucket_list_.get_deleter().size() = 0;
1515        if (__u.size() > 0)
1516        {
1517            __p1_.first().__next_ = __u.__p1_.first().__next_;
1518            __u.__p1_.first().__next_ = nullptr;
1519            __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
1520                __p1_.first().__ptr();
1521            size() = __u.size();
1522            __u.size() = 0;
1523        }
1524    }
1525}
1526
1527#endif  // _LIBCPP_CXX03_LANG
1528
1529template <class _Tp, class _Hash, class _Equal, class _Alloc>
1530__hash_table<_Tp, _Hash, _Equal, _Alloc>::~__hash_table()
1531{
1532#if defined(_LIBCPP_CXX03_LANG)
1533    static_assert((is_copy_constructible<key_equal>::value),
1534                 "Predicate must be copy-constructible.");
1535    static_assert((is_copy_constructible<hasher>::value),
1536                 "Hasher must be copy-constructible.");
1537#endif
1538
1539    __deallocate_node(__p1_.first().__next_);
1540#if _LIBCPP_DEBUG_LEVEL >= 2
1541    __get_db()->__erase_c(this);
1542#endif
1543}
1544
1545template <class _Tp, class _Hash, class _Equal, class _Alloc>
1546void
1547__hash_table<_Tp, _Hash, _Equal, _Alloc>::__copy_assign_alloc(
1548        const __hash_table& __u, true_type)
1549{
1550    if (__node_alloc() != __u.__node_alloc())
1551    {
1552        clear();
1553        __bucket_list_.reset();
1554        __bucket_list_.get_deleter().size() = 0;
1555    }
1556    __bucket_list_.get_deleter().__alloc() = __u.__bucket_list_.get_deleter().__alloc();
1557    __node_alloc() = __u.__node_alloc();
1558}
1559
1560template <class _Tp, class _Hash, class _Equal, class _Alloc>
1561__hash_table<_Tp, _Hash, _Equal, _Alloc>&
1562__hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(const __hash_table& __u)
1563{
1564    if (this != &__u)
1565    {
1566        __copy_assign_alloc(__u);
1567        hash_function() = __u.hash_function();
1568        key_eq() = __u.key_eq();
1569        max_load_factor() = __u.max_load_factor();
1570        __assign_multi(__u.begin(), __u.end());
1571    }
1572    return *this;
1573}
1574
1575template <class _Tp, class _Hash, class _Equal, class _Alloc>
1576void
1577__hash_table<_Tp, _Hash, _Equal, _Alloc>::__deallocate_node(__next_pointer __np)
1578    _NOEXCEPT
1579{
1580    __node_allocator& __na = __node_alloc();
1581    while (__np != nullptr)
1582    {
1583        __next_pointer __next = __np->__next_;
1584#if _LIBCPP_DEBUG_LEVEL >= 2
1585        __c_node* __c = __get_db()->__find_c_and_lock(this);
1586        for (__i_node** __p = __c->end_; __p != __c->beg_; )
1587        {
1588            --__p;
1589            iterator* __i = static_cast<iterator*>((*__p)->__i_);
1590            if (__i->__node_ == __np)
1591            {
1592                (*__p)->__c_ = nullptr;
1593                if (--__c->end_ != __p)
1594                    memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
1595            }
1596        }
1597        __get_db()->unlock();
1598#endif
1599        __node_pointer __real_np = __np->__upcast();
1600        __node_traits::destroy(__na, _NodeTypes::__get_ptr(__real_np->__value_));
1601        __node_traits::deallocate(__na, __real_np, 1);
1602        __np = __next;
1603    }
1604}
1605
1606template <class _Tp, class _Hash, class _Equal, class _Alloc>
1607typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1608__hash_table<_Tp, _Hash, _Equal, _Alloc>::__detach() _NOEXCEPT
1609{
1610    size_type __bc = bucket_count();
1611    for (size_type __i = 0; __i < __bc; ++__i)
1612        __bucket_list_[__i] = nullptr;
1613    size() = 0;
1614    __next_pointer __cache = __p1_.first().__next_;
1615    __p1_.first().__next_ = nullptr;
1616    return __cache;
1617}
1618
1619#ifndef _LIBCPP_CXX03_LANG
1620
1621template <class _Tp, class _Hash, class _Equal, class _Alloc>
1622void
1623__hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(
1624        __hash_table& __u, true_type)
1625    _NOEXCEPT_(
1626        is_nothrow_move_assignable<__node_allocator>::value &&
1627        is_nothrow_move_assignable<hasher>::value &&
1628        is_nothrow_move_assignable<key_equal>::value)
1629{
1630    clear();
1631    __bucket_list_.reset(__u.__bucket_list_.release());
1632    __bucket_list_.get_deleter().size() = __u.__bucket_list_.get_deleter().size();
1633    __u.__bucket_list_.get_deleter().size() = 0;
1634    __move_assign_alloc(__u);
1635    size() = __u.size();
1636    hash_function() = _VSTD::move(__u.hash_function());
1637    max_load_factor() = __u.max_load_factor();
1638    key_eq() = _VSTD::move(__u.key_eq());
1639    __p1_.first().__next_ = __u.__p1_.first().__next_;
1640    if (size() > 0)
1641    {
1642        __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
1643            __p1_.first().__ptr();
1644        __u.__p1_.first().__next_ = nullptr;
1645        __u.size() = 0;
1646    }
1647#if _LIBCPP_DEBUG_LEVEL >= 2
1648    __get_db()->swap(this, &__u);
1649#endif
1650}
1651
1652template <class _Tp, class _Hash, class _Equal, class _Alloc>
1653void
1654__hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(
1655        __hash_table& __u, false_type)
1656{
1657    if (__node_alloc() == __u.__node_alloc())
1658        __move_assign(__u, true_type());
1659    else
1660    {
1661        hash_function() = _VSTD::move(__u.hash_function());
1662        key_eq() = _VSTD::move(__u.key_eq());
1663        max_load_factor() = __u.max_load_factor();
1664        if (bucket_count() != 0)
1665        {
1666            __next_pointer __cache = __detach();
1667#ifndef _LIBCPP_NO_EXCEPTIONS
1668            try
1669            {
1670#endif  // _LIBCPP_NO_EXCEPTIONS
1671                const_iterator __i = __u.begin();
1672                while (__cache != nullptr && __u.size() != 0)
1673                {
1674                    __cache->__upcast()->__value_ =
1675                        _VSTD::move(__u.remove(__i++)->__value_);
1676                    __next_pointer __next = __cache->__next_;
1677                    __node_insert_multi(__cache->__upcast());
1678                    __cache = __next;
1679                }
1680#ifndef _LIBCPP_NO_EXCEPTIONS
1681            }
1682            catch (...)
1683            {
1684                __deallocate_node(__cache);
1685                throw;
1686            }
1687#endif  // _LIBCPP_NO_EXCEPTIONS
1688            __deallocate_node(__cache);
1689        }
1690        const_iterator __i = __u.begin();
1691        while (__u.size() != 0)
1692        {
1693            __node_holder __h = __construct_node(_NodeTypes::__move(__u.remove(__i++)->__value_));
1694            __node_insert_multi(__h.get());
1695            __h.release();
1696        }
1697    }
1698}
1699
1700template <class _Tp, class _Hash, class _Equal, class _Alloc>
1701inline
1702__hash_table<_Tp, _Hash, _Equal, _Alloc>&
1703__hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(__hash_table&& __u)
1704    _NOEXCEPT_(
1705        __node_traits::propagate_on_container_move_assignment::value &&
1706        is_nothrow_move_assignable<__node_allocator>::value &&
1707        is_nothrow_move_assignable<hasher>::value &&
1708        is_nothrow_move_assignable<key_equal>::value)
1709{
1710    __move_assign(__u, integral_constant<bool,
1711                  __node_traits::propagate_on_container_move_assignment::value>());
1712    return *this;
1713}
1714
1715#endif  // _LIBCPP_CXX03_LANG
1716
1717template <class _Tp, class _Hash, class _Equal, class _Alloc>
1718template <class _InputIterator>
1719void
1720__hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_unique(_InputIterator __first,
1721                                                          _InputIterator __last)
1722{
1723    typedef iterator_traits<_InputIterator> _ITraits;
1724    typedef typename _ITraits::value_type _ItValueType;
1725    static_assert((is_same<_ItValueType, __container_value_type>::value),
1726                  "__assign_unique may only be called with the containers value type");
1727
1728    if (bucket_count() != 0)
1729    {
1730        __next_pointer __cache = __detach();
1731#ifndef _LIBCPP_NO_EXCEPTIONS
1732        try
1733        {
1734#endif  // _LIBCPP_NO_EXCEPTIONS
1735            for (; __cache != nullptr && __first != __last; ++__first)
1736            {
1737                __cache->__upcast()->__value_ = *__first;
1738                __next_pointer __next = __cache->__next_;
1739                __node_insert_unique(__cache->__upcast());
1740                __cache = __next;
1741            }
1742#ifndef _LIBCPP_NO_EXCEPTIONS
1743        }
1744        catch (...)
1745        {
1746            __deallocate_node(__cache);
1747            throw;
1748        }
1749#endif  // _LIBCPP_NO_EXCEPTIONS
1750        __deallocate_node(__cache);
1751    }
1752    for (; __first != __last; ++__first)
1753        __insert_unique(*__first);
1754}
1755
1756template <class _Tp, class _Hash, class _Equal, class _Alloc>
1757template <class _InputIterator>
1758void
1759__hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_multi(_InputIterator __first,
1760                                                         _InputIterator __last)
1761{
1762    typedef iterator_traits<_InputIterator> _ITraits;
1763    typedef typename _ITraits::value_type _ItValueType;
1764    static_assert((is_same<_ItValueType, __container_value_type>::value ||
1765                  is_same<_ItValueType, __node_value_type>::value),
1766                  "__assign_multi may only be called with the containers value type"
1767                  " or the nodes value type");
1768    if (bucket_count() != 0)
1769    {
1770        __next_pointer __cache = __detach();
1771#ifndef _LIBCPP_NO_EXCEPTIONS
1772        try
1773        {
1774#endif  // _LIBCPP_NO_EXCEPTIONS
1775            for (; __cache != nullptr && __first != __last; ++__first)
1776            {
1777                __cache->__upcast()->__value_ = *__first;
1778                __next_pointer __next = __cache->__next_;
1779                __node_insert_multi(__cache->__upcast());
1780                __cache = __next;
1781            }
1782#ifndef _LIBCPP_NO_EXCEPTIONS
1783        }
1784        catch (...)
1785        {
1786            __deallocate_node(__cache);
1787            throw;
1788        }
1789#endif  // _LIBCPP_NO_EXCEPTIONS
1790        __deallocate_node(__cache);
1791    }
1792    for (; __first != __last; ++__first)
1793        __insert_multi(_NodeTypes::__get_value(*__first));
1794}
1795
1796template <class _Tp, class _Hash, class _Equal, class _Alloc>
1797inline
1798typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1799__hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() _NOEXCEPT
1800{
1801#if _LIBCPP_DEBUG_LEVEL >= 2
1802    return iterator(__p1_.first().__next_, this);
1803#else
1804    return iterator(__p1_.first().__next_);
1805#endif
1806}
1807
1808template <class _Tp, class _Hash, class _Equal, class _Alloc>
1809inline
1810typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1811__hash_table<_Tp, _Hash, _Equal, _Alloc>::end() _NOEXCEPT
1812{
1813#if _LIBCPP_DEBUG_LEVEL >= 2
1814    return iterator(nullptr, this);
1815#else
1816    return iterator(nullptr);
1817#endif
1818}
1819
1820template <class _Tp, class _Hash, class _Equal, class _Alloc>
1821inline
1822typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
1823__hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() const _NOEXCEPT
1824{
1825#if _LIBCPP_DEBUG_LEVEL >= 2
1826    return const_iterator(__p1_.first().__next_, this);
1827#else
1828    return const_iterator(__p1_.first().__next_);
1829#endif
1830}
1831
1832template <class _Tp, class _Hash, class _Equal, class _Alloc>
1833inline
1834typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
1835__hash_table<_Tp, _Hash, _Equal, _Alloc>::end() const _NOEXCEPT
1836{
1837#if _LIBCPP_DEBUG_LEVEL >= 2
1838    return const_iterator(nullptr, this);
1839#else
1840    return const_iterator(nullptr);
1841#endif
1842}
1843
1844template <class _Tp, class _Hash, class _Equal, class _Alloc>
1845void
1846__hash_table<_Tp, _Hash, _Equal, _Alloc>::clear() _NOEXCEPT
1847{
1848    if (size() > 0)
1849    {
1850        __deallocate_node(__p1_.first().__next_);
1851        __p1_.first().__next_ = nullptr;
1852        size_type __bc = bucket_count();
1853        for (size_type __i = 0; __i < __bc; ++__i)
1854            __bucket_list_[__i] = nullptr;
1855        size() = 0;
1856    }
1857}
1858
1859
1860// Prepare the container for an insertion of the value __value with the hash
1861// __hash. This does a lookup into the container to see if __value is already
1862// present, and performs a rehash if necessary. Returns a pointer to the
1863// existing element if it exists, otherwise nullptr.
1864//
1865// Note that this function does forward exceptions if key_eq() throws, and never
1866// mutates __value or actually inserts into the map.
1867template <class _Tp, class _Hash, class _Equal, class _Alloc>
1868_LIBCPP_INLINE_VISIBILITY
1869typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1870__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique_prepare(
1871    size_t __hash, value_type& __value)
1872{
1873    size_type __bc = bucket_count();
1874
1875    if (__bc != 0)
1876    {
1877        size_t __chash = __constrain_hash(__hash, __bc);
1878        __next_pointer __ndptr = __bucket_list_[__chash];
1879        if (__ndptr != nullptr)
1880        {
1881            for (__ndptr = __ndptr->__next_; __ndptr != nullptr &&
1882                                             __constrain_hash(__ndptr->__hash(), __bc) == __chash;
1883                                                     __ndptr = __ndptr->__next_)
1884            {
1885                if (key_eq()(__ndptr->__upcast()->__value_, __value))
1886                    return __ndptr;
1887            }
1888        }
1889    }
1890    if (size()+1 > __bc * max_load_factor() || __bc == 0)
1891    {
1892        rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
1893                                     size_type(ceil(float(size() + 1) / max_load_factor()))));
1894    }
1895    return nullptr;
1896}
1897
1898// Insert the node __nd into the container by pushing it into the right bucket,
1899// and updating size(). Assumes that __nd->__hash is up-to-date, and that
1900// rehashing has already occurred and that no element with the same key exists
1901// in the map.
1902template <class _Tp, class _Hash, class _Equal, class _Alloc>
1903_LIBCPP_INLINE_VISIBILITY
1904void
1905__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique_perform(
1906    __node_pointer __nd) _NOEXCEPT
1907{
1908    size_type __bc = bucket_count();
1909    size_t __chash = __constrain_hash(__nd->__hash(), __bc);
1910    // insert_after __bucket_list_[__chash], or __first_node if bucket is null
1911    __next_pointer __pn = __bucket_list_[__chash];
1912    if (__pn == nullptr)
1913    {
1914        __pn =__p1_.first().__ptr();
1915        __nd->__next_ = __pn->__next_;
1916        __pn->__next_ = __nd->__ptr();
1917        // fix up __bucket_list_
1918        __bucket_list_[__chash] = __pn;
1919        if (__nd->__next_ != nullptr)
1920            __bucket_list_[__constrain_hash(__nd->__next_->__hash(), __bc)] = __nd->__ptr();
1921    }
1922    else
1923    {
1924        __nd->__next_ = __pn->__next_;
1925        __pn->__next_ = __nd->__ptr();
1926    }
1927    ++size();
1928}
1929
1930template <class _Tp, class _Hash, class _Equal, class _Alloc>
1931pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
1932__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique(__node_pointer __nd)
1933{
1934    __nd->__hash_ = hash_function()(__nd->__value_);
1935    __next_pointer __existing_node =
1936        __node_insert_unique_prepare(__nd->__hash(), __nd->__value_);
1937
1938    // Insert the node, unless it already exists in the container.
1939    bool __inserted = false;
1940    if (__existing_node == nullptr)
1941    {
1942        __node_insert_unique_perform(__nd);
1943        __existing_node = __nd->__ptr();
1944        __inserted = true;
1945    }
1946#if _LIBCPP_DEBUG_LEVEL >= 2
1947    return pair<iterator, bool>(iterator(__existing_node, this), __inserted);
1948#else
1949    return pair<iterator, bool>(iterator(__existing_node), __inserted);
1950#endif
1951}
1952
1953// Prepare the container for an insertion of the value __cp_val with the hash
1954// __cp_hash. This does a lookup into the container to see if __cp_value is
1955// already present, and performs a rehash if necessary. Returns a pointer to the
1956// last occurance of __cp_val in the map.
1957//
1958// Note that this function does forward exceptions if key_eq() throws, and never
1959// mutates __value or actually inserts into the map.
1960template <class _Tp, class _Hash, class _Equal, class _Alloc>
1961typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1962__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi_prepare(
1963    size_t __cp_hash, value_type& __cp_val)
1964{
1965    size_type __bc = bucket_count();
1966    if (size()+1 > __bc * max_load_factor() || __bc == 0)
1967    {
1968        rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
1969                       size_type(ceil(float(size() + 1) / max_load_factor()))));
1970        __bc = bucket_count();
1971    }
1972    size_t __chash = __constrain_hash(__cp_hash, __bc);
1973    __next_pointer __pn = __bucket_list_[__chash];
1974    if (__pn != nullptr)
1975    {
1976        for (bool __found = false; __pn->__next_ != nullptr &&
1977                                   __constrain_hash(__pn->__next_->__hash(), __bc) == __chash;
1978                                                           __pn = __pn->__next_)
1979        {
1980            //      __found    key_eq()     action
1981            //      false       false       loop
1982            //      true        true        loop
1983            //      false       true        set __found to true
1984            //      true        false       break
1985            if (__found != (__pn->__next_->__hash() == __cp_hash &&
1986                            key_eq()(__pn->__next_->__upcast()->__value_, __cp_val)))
1987            {
1988                if (!__found)
1989                    __found = true;
1990                else
1991                    break;
1992            }
1993        }
1994    }
1995    return __pn;
1996}
1997
1998// Insert the node __cp into the container after __pn (which is the last node in
1999// the bucket that compares equal to __cp). Rehashing, and checking for
2000// uniqueness has already been performed (in __node_insert_multi_prepare), so
2001// all we need to do is update the bucket and size(). Assumes that __cp->__hash
2002// is up-to-date.
2003template <class _Tp, class _Hash, class _Equal, class _Alloc>
2004void
2005__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi_perform(
2006    __node_pointer __cp, __next_pointer __pn) _NOEXCEPT
2007{
2008    size_type __bc = bucket_count();
2009    size_t __chash = __constrain_hash(__cp->__hash_, __bc);
2010    if (__pn == nullptr)
2011    {
2012        __pn =__p1_.first().__ptr();
2013        __cp->__next_ = __pn->__next_;
2014        __pn->__next_ = __cp->__ptr();
2015        // fix up __bucket_list_
2016        __bucket_list_[__chash] = __pn;
2017        if (__cp->__next_ != nullptr)
2018            __bucket_list_[__constrain_hash(__cp->__next_->__hash(), __bc)]
2019                = __cp->__ptr();
2020    }
2021    else
2022    {
2023        __cp->__next_ = __pn->__next_;
2024        __pn->__next_ = __cp->__ptr();
2025        if (__cp->__next_ != nullptr)
2026        {
2027            size_t __nhash = __constrain_hash(__cp->__next_->__hash(), __bc);
2028            if (__nhash != __chash)
2029                __bucket_list_[__nhash] = __cp->__ptr();
2030        }
2031    }
2032    ++size();
2033}
2034
2035
2036template <class _Tp, class _Hash, class _Equal, class _Alloc>
2037typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2038__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(__node_pointer __cp)
2039{
2040    __cp->__hash_ = hash_function()(__cp->__value_);
2041    __next_pointer __pn = __node_insert_multi_prepare(__cp->__hash(), __cp->__value_);
2042    __node_insert_multi_perform(__cp, __pn);
2043
2044#if _LIBCPP_DEBUG_LEVEL >= 2
2045    return iterator(__cp->__ptr(), this);
2046#else
2047    return iterator(__cp->__ptr());
2048#endif
2049}
2050
2051template <class _Tp, class _Hash, class _Equal, class _Alloc>
2052typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2053__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(
2054        const_iterator __p, __node_pointer __cp)
2055{
2056#if _LIBCPP_DEBUG_LEVEL >= 2
2057    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
2058        "unordered container::emplace_hint(const_iterator, args...) called with an iterator not"
2059        " referring to this unordered container");
2060#endif
2061    if (__p != end() && key_eq()(*__p, __cp->__value_))
2062    {
2063        __next_pointer __np = __p.__node_;
2064        __cp->__hash_ = __np->__hash();
2065        size_type __bc = bucket_count();
2066        if (size()+1 > __bc * max_load_factor() || __bc == 0)
2067        {
2068            rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
2069                           size_type(ceil(float(size() + 1) / max_load_factor()))));
2070            __bc = bucket_count();
2071        }
2072        size_t __chash = __constrain_hash(__cp->__hash_, __bc);
2073        __next_pointer __pp = __bucket_list_[__chash];
2074        while (__pp->__next_ != __np)
2075            __pp = __pp->__next_;
2076        __cp->__next_ = __np;
2077        __pp->__next_ = static_cast<__next_pointer>(__cp);
2078        ++size();
2079#if _LIBCPP_DEBUG_LEVEL >= 2
2080        return iterator(static_cast<__next_pointer>(__cp), this);
2081#else
2082        return iterator(static_cast<__next_pointer>(__cp));
2083#endif
2084    }
2085    return __node_insert_multi(__cp);
2086}
2087
2088
2089
2090#ifndef _LIBCPP_CXX03_LANG
2091template <class _Tp, class _Hash, class _Equal, class _Alloc>
2092template <class _Key, class ..._Args>
2093pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
2094__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const& __k, _Args&&... __args)
2095#else
2096template <class _Tp, class _Hash, class _Equal, class _Alloc>
2097template <class _Key, class _Args>
2098pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
2099__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const& __k, _Args& __args)
2100#endif
2101{
2102
2103    size_t __hash = hash_function()(__k);
2104    size_type __bc = bucket_count();
2105    bool __inserted = false;
2106    __next_pointer __nd;
2107    size_t __chash;
2108    if (__bc != 0)
2109    {
2110        __chash = __constrain_hash(__hash, __bc);
2111        __nd = __bucket_list_[__chash];
2112        if (__nd != nullptr)
2113        {
2114            for (__nd = __nd->__next_; __nd != nullptr &&
2115                (__nd->__hash() == __hash || __constrain_hash(__nd->__hash(), __bc) == __chash);
2116                                                           __nd = __nd->__next_)
2117            {
2118                if (key_eq()(__nd->__upcast()->__value_, __k))
2119                    goto __done;
2120            }
2121        }
2122    }
2123    {
2124#ifndef _LIBCPP_CXX03_LANG
2125        __node_holder __h = __construct_node_hash(__hash, _VSTD::forward<_Args>(__args)...);
2126#else
2127        __node_holder __h = __construct_node_hash(__hash, __args);
2128#endif
2129        if (size()+1 > __bc * max_load_factor() || __bc == 0)
2130        {
2131            rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
2132                           size_type(ceil(float(size() + 1) / max_load_factor()))));
2133            __bc = bucket_count();
2134            __chash = __constrain_hash(__hash, __bc);
2135        }
2136        // insert_after __bucket_list_[__chash], or __first_node if bucket is null
2137        __next_pointer __pn = __bucket_list_[__chash];
2138        if (__pn == nullptr)
2139        {
2140            __pn = __p1_.first().__ptr();
2141            __h->__next_ = __pn->__next_;
2142            __pn->__next_ = __h.get()->__ptr();
2143            // fix up __bucket_list_
2144            __bucket_list_[__chash] = __pn;
2145            if (__h->__next_ != nullptr)
2146                __bucket_list_[__constrain_hash(__h->__next_->__hash(), __bc)]
2147                    = __h.get()->__ptr();
2148        }
2149        else
2150        {
2151            __h->__next_ = __pn->__next_;
2152            __pn->__next_ = static_cast<__next_pointer>(__h.get());
2153        }
2154        __nd = static_cast<__next_pointer>(__h.release());
2155        // increment size
2156        ++size();
2157        __inserted = true;
2158    }
2159__done:
2160#if _LIBCPP_DEBUG_LEVEL >= 2
2161    return pair<iterator, bool>(iterator(__nd, this), __inserted);
2162#else
2163    return pair<iterator, bool>(iterator(__nd), __inserted);
2164#endif
2165}
2166
2167#ifndef _LIBCPP_CXX03_LANG
2168
2169template <class _Tp, class _Hash, class _Equal, class _Alloc>
2170template <class... _Args>
2171pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
2172__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_impl(_Args&&... __args)
2173{
2174    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
2175    pair<iterator, bool> __r = __node_insert_unique(__h.get());
2176    if (__r.second)
2177        __h.release();
2178    return __r;
2179}
2180
2181template <class _Tp, class _Hash, class _Equal, class _Alloc>
2182template <class... _Args>
2183typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2184__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_multi(_Args&&... __args)
2185{
2186    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
2187    iterator __r = __node_insert_multi(__h.get());
2188    __h.release();
2189    return __r;
2190}
2191
2192template <class _Tp, class _Hash, class _Equal, class _Alloc>
2193template <class... _Args>
2194typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2195__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_hint_multi(
2196        const_iterator __p, _Args&&... __args)
2197{
2198#if _LIBCPP_DEBUG_LEVEL >= 2
2199    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
2200        "unordered container::emplace_hint(const_iterator, args...) called with an iterator not"
2201        " referring to this unordered container");
2202#endif
2203    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
2204    iterator __r = __node_insert_multi(__p, __h.get());
2205    __h.release();
2206    return __r;
2207}
2208
2209#else // _LIBCPP_CXX03_LANG
2210
2211template <class _Tp, class _Hash, class _Equal, class _Alloc>
2212typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2213__hash_table<_Tp, _Hash, _Equal, _Alloc>::__insert_multi(const __container_value_type& __x)
2214{
2215    __node_holder __h = __construct_node(__x);
2216    iterator __r = __node_insert_multi(__h.get());
2217    __h.release();
2218    return __r;
2219}
2220
2221template <class _Tp, class _Hash, class _Equal, class _Alloc>
2222typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2223__hash_table<_Tp, _Hash, _Equal, _Alloc>::__insert_multi(const_iterator __p,
2224                                                         const __container_value_type& __x)
2225{
2226#if _LIBCPP_DEBUG_LEVEL >= 2
2227    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
2228        "unordered container::insert(const_iterator, lvalue) called with an iterator not"
2229        " referring to this unordered container");
2230#endif
2231    __node_holder __h = __construct_node(__x);
2232    iterator __r = __node_insert_multi(__p, __h.get());
2233    __h.release();
2234    return __r;
2235}
2236
2237#endif  // _LIBCPP_CXX03_LANG
2238
2239#if _LIBCPP_STD_VER > 14
2240template <class _Tp, class _Hash, class _Equal, class _Alloc>
2241template <class _NodeHandle, class _InsertReturnType>
2242_LIBCPP_INLINE_VISIBILITY
2243_InsertReturnType
2244__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_unique(
2245    _NodeHandle&& __nh)
2246{
2247    if (__nh.empty())
2248        return _InsertReturnType{end(), false, _NodeHandle()};
2249    pair<iterator, bool> __result = __node_insert_unique(__nh.__ptr_);
2250    if (__result.second)
2251        __nh.__release_ptr();
2252    return _InsertReturnType{__result.first, __result.second, _VSTD::move(__nh)};
2253}
2254
2255template <class _Tp, class _Hash, class _Equal, class _Alloc>
2256template <class _NodeHandle>
2257_LIBCPP_INLINE_VISIBILITY
2258typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2259__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_unique(
2260    const_iterator, _NodeHandle&& __nh)
2261{
2262    if (__nh.empty())
2263        return end();
2264    pair<iterator, bool> __result = __node_insert_unique(__nh.__ptr_);
2265    if (__result.second)
2266        __nh.__release_ptr();
2267    return __result.first;
2268}
2269
2270template <class _Tp, class _Hash, class _Equal, class _Alloc>
2271template <class _NodeHandle>
2272_LIBCPP_INLINE_VISIBILITY
2273_NodeHandle
2274__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_extract(
2275    key_type const& __key)
2276{
2277    iterator __i = find(__key);
2278    if (__i == end())
2279        return _NodeHandle();
2280    return __node_handle_extract<_NodeHandle>(__i);
2281}
2282
2283template <class _Tp, class _Hash, class _Equal, class _Alloc>
2284template <class _NodeHandle>
2285_LIBCPP_INLINE_VISIBILITY
2286_NodeHandle
2287__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_extract(
2288    const_iterator __p)
2289{
2290    allocator_type __alloc(__node_alloc());
2291    return _NodeHandle(remove(__p).release(), __alloc);
2292}
2293
2294template <class _Tp, class _Hash, class _Equal, class _Alloc>
2295template <class _Table>
2296_LIBCPP_INLINE_VISIBILITY
2297void
2298__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_merge_unique(
2299    _Table& __source)
2300{
2301    static_assert(is_same<__node, typename _Table::__node>::value, "");
2302
2303    for (typename _Table::iterator __it = __source.begin();
2304         __it != __source.end();)
2305    {
2306        __node_pointer __src_ptr = __it.__node_->__upcast();
2307        size_t __hash = hash_function()(__src_ptr->__value_);
2308        __next_pointer __existing_node =
2309            __node_insert_unique_prepare(__hash, __src_ptr->__value_);
2310        auto __prev_iter = __it++;
2311        if (__existing_node == nullptr)
2312        {
2313            (void)__source.remove(__prev_iter).release();
2314            __src_ptr->__hash_ = __hash;
2315            __node_insert_unique_perform(__src_ptr);
2316        }
2317    }
2318}
2319
2320template <class _Tp, class _Hash, class _Equal, class _Alloc>
2321template <class _NodeHandle>
2322_LIBCPP_INLINE_VISIBILITY
2323typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2324__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_multi(
2325    _NodeHandle&& __nh)
2326{
2327    if (__nh.empty())
2328        return end();
2329    iterator __result = __node_insert_multi(__nh.__ptr_);
2330    __nh.__release_ptr();
2331    return __result;
2332}
2333
2334template <class _Tp, class _Hash, class _Equal, class _Alloc>
2335template <class _NodeHandle>
2336_LIBCPP_INLINE_VISIBILITY
2337typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2338__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_multi(
2339    const_iterator __hint, _NodeHandle&& __nh)
2340{
2341    if (__nh.empty())
2342        return end();
2343    iterator __result = __node_insert_multi(__hint, __nh.__ptr_);
2344    __nh.__release_ptr();
2345    return __result;
2346}
2347
2348template <class _Tp, class _Hash, class _Equal, class _Alloc>
2349template <class _Table>
2350_LIBCPP_INLINE_VISIBILITY
2351void
2352__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_merge_multi(
2353    _Table& __source)
2354{
2355    static_assert(is_same<typename _Table::__node, __node>::value, "");
2356
2357    for (typename _Table::iterator __it = __source.begin();
2358         __it != __source.end();)
2359    {
2360        __node_pointer __src_ptr = __it.__node_->__upcast();
2361        size_t __src_hash = hash_function()(__src_ptr->__value_);
2362        __next_pointer __pn =
2363            __node_insert_multi_prepare(__src_hash, __src_ptr->__value_);
2364        (void)__source.remove(__it++).release();
2365        __src_ptr->__hash_ = __src_hash;
2366        __node_insert_multi_perform(__src_ptr, __pn);
2367    }
2368}
2369#endif  // _LIBCPP_STD_VER > 14
2370
2371template <class _Tp, class _Hash, class _Equal, class _Alloc>
2372void
2373__hash_table<_Tp, _Hash, _Equal, _Alloc>::rehash(size_type __n)
2374_LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
2375{
2376    if (__n == 1)
2377        __n = 2;
2378    else if (__n & (__n - 1))
2379        __n = __next_prime(__n);
2380    size_type __bc = bucket_count();
2381    if (__n > __bc)
2382        __rehash(__n);
2383    else if (__n < __bc)
2384    {
2385        __n = _VSTD::max<size_type>
2386              (
2387                  __n,
2388                  __is_hash_power2(__bc) ? __next_hash_pow2(size_t(ceil(float(size()) / max_load_factor()))) :
2389                                           __next_prime(size_t(ceil(float(size()) / max_load_factor())))
2390              );
2391        if (__n < __bc)
2392            __rehash(__n);
2393    }
2394}
2395
2396template <class _Tp, class _Hash, class _Equal, class _Alloc>
2397void
2398__hash_table<_Tp, _Hash, _Equal, _Alloc>::__rehash(size_type __nbc)
2399{
2400#if _LIBCPP_DEBUG_LEVEL >= 2
2401    __get_db()->__invalidate_all(this);
2402#endif  // _LIBCPP_DEBUG_LEVEL >= 2
2403    __pointer_allocator& __npa = __bucket_list_.get_deleter().__alloc();
2404    __bucket_list_.reset(__nbc > 0 ?
2405                      __pointer_alloc_traits::allocate(__npa, __nbc) : nullptr);
2406    __bucket_list_.get_deleter().size() = __nbc;
2407    if (__nbc > 0)
2408    {
2409        for (size_type __i = 0; __i < __nbc; ++__i)
2410            __bucket_list_[__i] = nullptr;
2411        __next_pointer __pp = __p1_.first().__ptr();
2412        __next_pointer __cp = __pp->__next_;
2413        if (__cp != nullptr)
2414        {
2415            size_type __chash = __constrain_hash(__cp->__hash(), __nbc);
2416            __bucket_list_[__chash] = __pp;
2417            size_type __phash = __chash;
2418            for (__pp = __cp, __cp = __cp->__next_; __cp != nullptr;
2419                                                           __cp = __pp->__next_)
2420            {
2421                __chash = __constrain_hash(__cp->__hash(), __nbc);
2422                if (__chash == __phash)
2423                    __pp = __cp;
2424                else
2425                {
2426                    if (__bucket_list_[__chash] == nullptr)
2427                    {
2428                        __bucket_list_[__chash] = __pp;
2429                        __pp = __cp;
2430                        __phash = __chash;
2431                    }
2432                    else
2433                    {
2434                        __next_pointer __np = __cp;
2435                        for (; __np->__next_ != nullptr &&
2436                               key_eq()(__cp->__upcast()->__value_,
2437                                        __np->__next_->__upcast()->__value_);
2438                                                           __np = __np->__next_)
2439                            ;
2440                        __pp->__next_ = __np->__next_;
2441                        __np->__next_ = __bucket_list_[__chash]->__next_;
2442                        __bucket_list_[__chash]->__next_ = __cp;
2443
2444                    }
2445                }
2446            }
2447        }
2448    }
2449}
2450
2451template <class _Tp, class _Hash, class _Equal, class _Alloc>
2452template <class _Key>
2453typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2454__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k)
2455{
2456    size_t __hash = hash_function()(__k);
2457    size_type __bc = bucket_count();
2458    if (__bc != 0)
2459    {
2460        size_t __chash = __constrain_hash(__hash, __bc);
2461        __next_pointer __nd = __bucket_list_[__chash];
2462        if (__nd != nullptr)
2463        {
2464            for (__nd = __nd->__next_; __nd != nullptr &&
2465                (__nd->__hash() == __hash
2466                  || __constrain_hash(__nd->__hash(), __bc) == __chash);
2467                                                           __nd = __nd->__next_)
2468            {
2469                if ((__nd->__hash() == __hash)
2470                    && key_eq()(__nd->__upcast()->__value_, __k))
2471#if _LIBCPP_DEBUG_LEVEL >= 2
2472                    return iterator(__nd, this);
2473#else
2474                    return iterator(__nd);
2475#endif
2476            }
2477        }
2478    }
2479    return end();
2480}
2481
2482template <class _Tp, class _Hash, class _Equal, class _Alloc>
2483template <class _Key>
2484typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
2485__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k) const
2486{
2487    size_t __hash = hash_function()(__k);
2488    size_type __bc = bucket_count();
2489    if (__bc != 0)
2490    {
2491        size_t __chash = __constrain_hash(__hash, __bc);
2492        __next_pointer __nd = __bucket_list_[__chash];
2493        if (__nd != nullptr)
2494        {
2495            for (__nd = __nd->__next_; __nd != nullptr &&
2496                (__hash == __nd->__hash()
2497                    || __constrain_hash(__nd->__hash(), __bc) == __chash);
2498                                                           __nd = __nd->__next_)
2499            {
2500                if ((__nd->__hash() == __hash)
2501                    && key_eq()(__nd->__upcast()->__value_, __k))
2502#if _LIBCPP_DEBUG_LEVEL >= 2
2503                    return const_iterator(__nd, this);
2504#else
2505                    return const_iterator(__nd);
2506#endif
2507            }
2508        }
2509
2510    }
2511    return end();
2512}
2513
2514#ifndef _LIBCPP_CXX03_LANG
2515
2516template <class _Tp, class _Hash, class _Equal, class _Alloc>
2517template <class ..._Args>
2518typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2519__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node(_Args&& ...__args)
2520{
2521    static_assert(!__is_hash_value_type<_Args...>::value,
2522                  "Construct cannot be called with a hash value type");
2523    __node_allocator& __na = __node_alloc();
2524    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2525    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), _VSTD::forward<_Args>(__args)...);
2526    __h.get_deleter().__value_constructed = true;
2527    __h->__hash_ = hash_function()(__h->__value_);
2528    __h->__next_ = nullptr;
2529    return __h;
2530}
2531
2532template <class _Tp, class _Hash, class _Equal, class _Alloc>
2533template <class _First, class ..._Rest>
2534typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2535__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(
2536    size_t __hash, _First&& __f, _Rest&& ...__rest)
2537{
2538    static_assert(!__is_hash_value_type<_First, _Rest...>::value,
2539                  "Construct cannot be called with a hash value type");
2540    __node_allocator& __na = __node_alloc();
2541    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2542    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_),
2543                             _VSTD::forward<_First>(__f),
2544                             _VSTD::forward<_Rest>(__rest)...);
2545    __h.get_deleter().__value_constructed = true;
2546    __h->__hash_ = __hash;
2547    __h->__next_ = nullptr;
2548    return __h;
2549}
2550
2551#else  // _LIBCPP_CXX03_LANG
2552
2553template <class _Tp, class _Hash, class _Equal, class _Alloc>
2554typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2555__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node(const __container_value_type& __v)
2556{
2557    __node_allocator& __na = __node_alloc();
2558    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2559    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), __v);
2560    __h.get_deleter().__value_constructed = true;
2561    __h->__hash_ = hash_function()(__h->__value_);
2562    __h->__next_ = nullptr;
2563    return _LIBCPP_EXPLICIT_MOVE(__h);  // explicitly moved for C++03
2564}
2565
2566template <class _Tp, class _Hash, class _Equal, class _Alloc>
2567typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2568__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(size_t __hash,
2569                                                                const __container_value_type& __v)
2570{
2571    __node_allocator& __na = __node_alloc();
2572    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2573    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), __v);
2574    __h.get_deleter().__value_constructed = true;
2575    __h->__hash_ = __hash;
2576    __h->__next_ = nullptr;
2577    return _LIBCPP_EXPLICIT_MOVE(__h);  // explicitly moved for C++03
2578}
2579
2580#endif  // _LIBCPP_CXX03_LANG
2581
2582template <class _Tp, class _Hash, class _Equal, class _Alloc>
2583typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2584__hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __p)
2585{
2586    __next_pointer __np = __p.__node_;
2587#if _LIBCPP_DEBUG_LEVEL >= 2
2588    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
2589        "unordered container erase(iterator) called with an iterator not"
2590        " referring to this container");
2591    _LIBCPP_ASSERT(__p != end(),
2592        "unordered container erase(iterator) called with a non-dereferenceable iterator");
2593    iterator __r(__np, this);
2594#else
2595    iterator __r(__np);
2596#endif
2597    ++__r;
2598    remove(__p);
2599    return __r;
2600}
2601
2602template <class _Tp, class _Hash, class _Equal, class _Alloc>
2603typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2604__hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __first,
2605                                                const_iterator __last)
2606{
2607#if _LIBCPP_DEBUG_LEVEL >= 2
2608    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__first) == this,
2609        "unodered container::erase(iterator, iterator) called with an iterator not"
2610        " referring to this unodered container");
2611    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__last) == this,
2612        "unodered container::erase(iterator, iterator) called with an iterator not"
2613        " referring to this unodered container");
2614#endif
2615    for (const_iterator __p = __first; __first != __last; __p = __first)
2616    {
2617        ++__first;
2618        erase(__p);
2619    }
2620    __next_pointer __np = __last.__node_;
2621#if _LIBCPP_DEBUG_LEVEL >= 2
2622    return iterator (__np, this);
2623#else
2624    return iterator (__np);
2625#endif
2626}
2627
2628template <class _Tp, class _Hash, class _Equal, class _Alloc>
2629template <class _Key>
2630typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2631__hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_unique(const _Key& __k)
2632{
2633    iterator __i = find(__k);
2634    if (__i == end())
2635        return 0;
2636    erase(__i);
2637    return 1;
2638}
2639
2640template <class _Tp, class _Hash, class _Equal, class _Alloc>
2641template <class _Key>
2642typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2643__hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_multi(const _Key& __k)
2644{
2645    size_type __r = 0;
2646    iterator __i = find(__k);
2647    if (__i != end())
2648    {
2649        iterator __e = end();
2650        do
2651        {
2652            erase(__i++);
2653            ++__r;
2654        } while (__i != __e && key_eq()(*__i, __k));
2655    }
2656    return __r;
2657}
2658
2659template <class _Tp, class _Hash, class _Equal, class _Alloc>
2660typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2661__hash_table<_Tp, _Hash, _Equal, _Alloc>::remove(const_iterator __p) _NOEXCEPT
2662{
2663    // current node
2664    __next_pointer __cn = __p.__node_;
2665    size_type __bc = bucket_count();
2666    size_t __chash = __constrain_hash(__cn->__hash(), __bc);
2667    // find previous node
2668    __next_pointer __pn = __bucket_list_[__chash];
2669    for (; __pn->__next_ != __cn; __pn = __pn->__next_)
2670        ;
2671    // Fix up __bucket_list_
2672        // if __pn is not in same bucket (before begin is not in same bucket) &&
2673        //    if __cn->__next_ is not in same bucket (nullptr is not in same bucket)
2674    if (__pn == __p1_.first().__ptr()
2675            || __constrain_hash(__pn->__hash(), __bc) != __chash)
2676    {
2677        if (__cn->__next_ == nullptr
2678            || __constrain_hash(__cn->__next_->__hash(), __bc) != __chash)
2679            __bucket_list_[__chash] = nullptr;
2680    }
2681        // if __cn->__next_ is not in same bucket (nullptr is in same bucket)
2682    if (__cn->__next_ != nullptr)
2683    {
2684        size_t __nhash = __constrain_hash(__cn->__next_->__hash(), __bc);
2685        if (__nhash != __chash)
2686            __bucket_list_[__nhash] = __pn;
2687    }
2688    // remove __cn
2689    __pn->__next_ = __cn->__next_;
2690    __cn->__next_ = nullptr;
2691    --size();
2692#if _LIBCPP_DEBUG_LEVEL >= 2
2693    __c_node* __c = __get_db()->__find_c_and_lock(this);
2694    for (__i_node** __dp = __c->end_; __dp != __c->beg_; )
2695    {
2696        --__dp;
2697        iterator* __i = static_cast<iterator*>((*__dp)->__i_);
2698        if (__i->__node_ == __cn)
2699        {
2700            (*__dp)->__c_ = nullptr;
2701            if (--__c->end_ != __dp)
2702                memmove(__dp, __dp+1, (__c->end_ - __dp)*sizeof(__i_node*));
2703        }
2704    }
2705    __get_db()->unlock();
2706#endif
2707    return __node_holder(__cn->__upcast(), _Dp(__node_alloc(), true));
2708}
2709
2710template <class _Tp, class _Hash, class _Equal, class _Alloc>
2711template <class _Key>
2712inline
2713typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2714__hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_unique(const _Key& __k) const
2715{
2716    return static_cast<size_type>(find(__k) != end());
2717}
2718
2719template <class _Tp, class _Hash, class _Equal, class _Alloc>
2720template <class _Key>
2721typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2722__hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_multi(const _Key& __k) const
2723{
2724    size_type __r = 0;
2725    const_iterator __i = find(__k);
2726    if (__i != end())
2727    {
2728        const_iterator __e = end();
2729        do
2730        {
2731            ++__i;
2732            ++__r;
2733        } while (__i != __e && key_eq()(*__i, __k));
2734    }
2735    return __r;
2736}
2737
2738template <class _Tp, class _Hash, class _Equal, class _Alloc>
2739template <class _Key>
2740pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
2741     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
2742__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(
2743        const _Key& __k)
2744{
2745    iterator __i = find(__k);
2746    iterator __j = __i;
2747    if (__i != end())
2748        ++__j;
2749    return pair<iterator, iterator>(__i, __j);
2750}
2751
2752template <class _Tp, class _Hash, class _Equal, class _Alloc>
2753template <class _Key>
2754pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
2755     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
2756__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(
2757        const _Key& __k) const
2758{
2759    const_iterator __i = find(__k);
2760    const_iterator __j = __i;
2761    if (__i != end())
2762        ++__j;
2763    return pair<const_iterator, const_iterator>(__i, __j);
2764}
2765
2766template <class _Tp, class _Hash, class _Equal, class _Alloc>
2767template <class _Key>
2768pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
2769     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
2770__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(
2771        const _Key& __k)
2772{
2773    iterator __i = find(__k);
2774    iterator __j = __i;
2775    if (__i != end())
2776    {
2777        iterator __e = end();
2778        do
2779        {
2780            ++__j;
2781        } while (__j != __e && key_eq()(*__j, __k));
2782    }
2783    return pair<iterator, iterator>(__i, __j);
2784}
2785
2786template <class _Tp, class _Hash, class _Equal, class _Alloc>
2787template <class _Key>
2788pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
2789     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
2790__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(
2791        const _Key& __k) const
2792{
2793    const_iterator __i = find(__k);
2794    const_iterator __j = __i;
2795    if (__i != end())
2796    {
2797        const_iterator __e = end();
2798        do
2799        {
2800            ++__j;
2801        } while (__j != __e && key_eq()(*__j, __k));
2802    }
2803    return pair<const_iterator, const_iterator>(__i, __j);
2804}
2805
2806template <class _Tp, class _Hash, class _Equal, class _Alloc>
2807void
2808__hash_table<_Tp, _Hash, _Equal, _Alloc>::swap(__hash_table& __u)
2809#if _LIBCPP_STD_VER <= 11
2810    _NOEXCEPT_(
2811        __is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value
2812        && (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value
2813              || __is_nothrow_swappable<__pointer_allocator>::value)
2814        && (!__node_traits::propagate_on_container_swap::value
2815              || __is_nothrow_swappable<__node_allocator>::value)
2816            )
2817#else
2818  _NOEXCEPT_(__is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value)
2819#endif
2820{
2821    _LIBCPP_ASSERT(__node_traits::propagate_on_container_swap::value ||
2822                   this->__node_alloc() == __u.__node_alloc(),
2823                   "list::swap: Either propagate_on_container_swap must be true"
2824                   " or the allocators must compare equal");
2825    {
2826    __node_pointer_pointer __npp = __bucket_list_.release();
2827    __bucket_list_.reset(__u.__bucket_list_.release());
2828    __u.__bucket_list_.reset(__npp);
2829    }
2830    _VSTD::swap(__bucket_list_.get_deleter().size(), __u.__bucket_list_.get_deleter().size());
2831    __swap_allocator(__bucket_list_.get_deleter().__alloc(),
2832             __u.__bucket_list_.get_deleter().__alloc());
2833    __swap_allocator(__node_alloc(), __u.__node_alloc());
2834    _VSTD::swap(__p1_.first().__next_, __u.__p1_.first().__next_);
2835    __p2_.swap(__u.__p2_);
2836    __p3_.swap(__u.__p3_);
2837    if (size() > 0)
2838        __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
2839            __p1_.first().__ptr();
2840    if (__u.size() > 0)
2841        __u.__bucket_list_[__constrain_hash(__u.__p1_.first().__next_->__hash(), __u.bucket_count())] =
2842            __u.__p1_.first().__ptr();
2843#if _LIBCPP_DEBUG_LEVEL >= 2
2844    __get_db()->swap(this, &__u);
2845#endif
2846}
2847
2848template <class _Tp, class _Hash, class _Equal, class _Alloc>
2849typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2850__hash_table<_Tp, _Hash, _Equal, _Alloc>::bucket_size(size_type __n) const
2851{
2852    _LIBCPP_ASSERT(__n < bucket_count(),
2853        "unordered container::bucket_size(n) called with n >= bucket_count()");
2854    __next_pointer __np = __bucket_list_[__n];
2855    size_type __bc = bucket_count();
2856    size_type __r = 0;
2857    if (__np != nullptr)
2858    {
2859        for (__np = __np->__next_; __np != nullptr &&
2860                                   __constrain_hash(__np->__hash(), __bc) == __n;
2861                                                    __np = __np->__next_, ++__r)
2862            ;
2863    }
2864    return __r;
2865}
2866
2867template <class _Tp, class _Hash, class _Equal, class _Alloc>
2868inline _LIBCPP_INLINE_VISIBILITY
2869void
2870swap(__hash_table<_Tp, _Hash, _Equal, _Alloc>& __x,
2871     __hash_table<_Tp, _Hash, _Equal, _Alloc>& __y)
2872    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
2873{
2874    __x.swap(__y);
2875}
2876
2877#if _LIBCPP_DEBUG_LEVEL >= 2
2878
2879template <class _Tp, class _Hash, class _Equal, class _Alloc>
2880bool
2881__hash_table<_Tp, _Hash, _Equal, _Alloc>::__dereferenceable(const const_iterator* __i) const
2882{
2883    return __i->__node_ != nullptr;
2884}
2885
2886template <class _Tp, class _Hash, class _Equal, class _Alloc>
2887bool
2888__hash_table<_Tp, _Hash, _Equal, _Alloc>::__decrementable(const const_iterator*) const
2889{
2890    return false;
2891}
2892
2893template <class _Tp, class _Hash, class _Equal, class _Alloc>
2894bool
2895__hash_table<_Tp, _Hash, _Equal, _Alloc>::__addable(const const_iterator*, ptrdiff_t) const
2896{
2897    return false;
2898}
2899
2900template <class _Tp, class _Hash, class _Equal, class _Alloc>
2901bool
2902__hash_table<_Tp, _Hash, _Equal, _Alloc>::__subscriptable(const const_iterator*, ptrdiff_t) const
2903{
2904    return false;
2905}
2906
2907#endif  // _LIBCPP_DEBUG_LEVEL >= 2
2908
2909_LIBCPP_END_NAMESPACE_STD
2910
2911_LIBCPP_POP_MACROS
2912
2913#endif  // _LIBCPP__HASH_TABLE
2914