xref: /freebsd/contrib/llvm-project/libcxx/include/__hash_table (revision a7dea1671b87c07d2d266f836bfa8b58efc7c134)
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
828public:
829    bool __value_constructed;
830
831    __hash_node_destructor(__hash_node_destructor const&) = default;
832    __hash_node_destructor& operator=(const __hash_node_destructor&) = delete;
833
834
835    _LIBCPP_INLINE_VISIBILITY
836    explicit __hash_node_destructor(allocator_type& __na,
837                                    bool __constructed = false) _NOEXCEPT
838        : __na_(__na),
839          __value_constructed(__constructed)
840        {}
841
842    _LIBCPP_INLINE_VISIBILITY
843    void operator()(pointer __p) _NOEXCEPT
844    {
845        if (__value_constructed)
846            __alloc_traits::destroy(__na_, _NodeTypes::__get_ptr(__p->__value_));
847        if (__p)
848            __alloc_traits::deallocate(__na_, __p, 1);
849    }
850
851    template <class> friend class __hash_map_node_destructor;
852};
853
854#if _LIBCPP_STD_VER > 14
855template <class _NodeType, class _Alloc>
856struct __generic_container_node_destructor;
857
858template <class _Tp, class _VoidPtr, class _Alloc>
859struct __generic_container_node_destructor<__hash_node<_Tp, _VoidPtr>, _Alloc>
860    : __hash_node_destructor<_Alloc>
861{
862    using __hash_node_destructor<_Alloc>::__hash_node_destructor;
863};
864#endif
865
866template <class _Key, class _Hash, class _Equal>
867struct __enforce_unordered_container_requirements {
868#ifndef _LIBCPP_CXX03_LANG
869    static_assert(__check_hash_requirements<_Key, _Hash>::value,
870    "the specified hash does not meet the Hash requirements");
871    static_assert(is_copy_constructible<_Equal>::value,
872    "the specified comparator is required to be copy constructible");
873#endif
874    typedef int type;
875};
876
877template <class _Key, class _Hash, class _Equal>
878#ifndef _LIBCPP_CXX03_LANG
879    _LIBCPP_DIAGNOSE_WARNING(!__invokable<_Equal const&, _Key const&, _Key const&>::value,
880    "the specified comparator type does not provide a viable const call operator")
881    _LIBCPP_DIAGNOSE_WARNING(!__invokable<_Hash const&, _Key const&>::value,
882    "the specified hash functor does not provide a viable const call operator")
883#endif
884typename __enforce_unordered_container_requirements<_Key, _Hash, _Equal>::type
885__diagnose_unordered_container_requirements(int);
886
887// This dummy overload is used so that the compiler won't emit a spurious
888// "no matching function for call to __diagnose_unordered_xxx" diagnostic
889// when the overload above causes a hard error.
890template <class _Key, class _Hash, class _Equal>
891int __diagnose_unordered_container_requirements(void*);
892
893template <class _Tp, class _Hash, class _Equal, class _Alloc>
894class __hash_table
895{
896public:
897    typedef _Tp    value_type;
898    typedef _Hash  hasher;
899    typedef _Equal key_equal;
900    typedef _Alloc allocator_type;
901
902private:
903    typedef allocator_traits<allocator_type> __alloc_traits;
904    typedef typename
905      __make_hash_node_types<value_type, typename __alloc_traits::void_pointer>::type
906                                                                     _NodeTypes;
907public:
908
909    typedef typename _NodeTypes::__node_value_type           __node_value_type;
910    typedef typename _NodeTypes::__container_value_type      __container_value_type;
911    typedef typename _NodeTypes::key_type                    key_type;
912    typedef value_type&                              reference;
913    typedef const value_type&                        const_reference;
914    typedef typename __alloc_traits::pointer         pointer;
915    typedef typename __alloc_traits::const_pointer   const_pointer;
916#ifndef _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
917    typedef typename __alloc_traits::size_type       size_type;
918#else
919    typedef typename _NodeTypes::size_type           size_type;
920#endif
921    typedef typename _NodeTypes::difference_type     difference_type;
922public:
923    // Create __node
924
925    typedef typename _NodeTypes::__node_type __node;
926    typedef typename __rebind_alloc_helper<__alloc_traits, __node>::type __node_allocator;
927    typedef allocator_traits<__node_allocator>       __node_traits;
928    typedef typename _NodeTypes::__void_pointer      __void_pointer;
929    typedef typename _NodeTypes::__node_pointer      __node_pointer;
930    typedef typename _NodeTypes::__node_pointer      __node_const_pointer;
931    typedef typename _NodeTypes::__node_base_type    __first_node;
932    typedef typename _NodeTypes::__node_base_pointer __node_base_pointer;
933    typedef typename _NodeTypes::__next_pointer      __next_pointer;
934
935private:
936    // check for sane allocator pointer rebinding semantics. Rebinding the
937    // allocator for a new pointer type should be exactly the same as rebinding
938    // the pointer using 'pointer_traits'.
939    static_assert((is_same<__node_pointer, typename __node_traits::pointer>::value),
940                  "Allocator does not rebind pointers in a sane manner.");
941    typedef typename __rebind_alloc_helper<__node_traits, __first_node>::type
942        __node_base_allocator;
943    typedef allocator_traits<__node_base_allocator> __node_base_traits;
944    static_assert((is_same<__node_base_pointer, typename __node_base_traits::pointer>::value),
945                 "Allocator does not rebind pointers in a sane manner.");
946
947private:
948
949    typedef typename __rebind_alloc_helper<__node_traits, __next_pointer>::type __pointer_allocator;
950    typedef __bucket_list_deallocator<__pointer_allocator> __bucket_list_deleter;
951    typedef unique_ptr<__next_pointer[], __bucket_list_deleter> __bucket_list;
952    typedef allocator_traits<__pointer_allocator>          __pointer_alloc_traits;
953    typedef typename __bucket_list_deleter::pointer       __node_pointer_pointer;
954
955    // --- Member data begin ---
956    __bucket_list                                         __bucket_list_;
957    __compressed_pair<__first_node, __node_allocator>     __p1_;
958    __compressed_pair<size_type, hasher>                  __p2_;
959    __compressed_pair<float, key_equal>                   __p3_;
960    // --- Member data end ---
961
962    _LIBCPP_INLINE_VISIBILITY
963    size_type& size() _NOEXCEPT {return __p2_.first();}
964public:
965    _LIBCPP_INLINE_VISIBILITY
966    size_type  size() const _NOEXCEPT {return __p2_.first();}
967
968    _LIBCPP_INLINE_VISIBILITY
969    hasher& hash_function() _NOEXCEPT {return __p2_.second();}
970    _LIBCPP_INLINE_VISIBILITY
971    const hasher& hash_function() const _NOEXCEPT {return __p2_.second();}
972
973    _LIBCPP_INLINE_VISIBILITY
974    float& max_load_factor() _NOEXCEPT {return __p3_.first();}
975    _LIBCPP_INLINE_VISIBILITY
976    float  max_load_factor() const _NOEXCEPT {return __p3_.first();}
977
978    _LIBCPP_INLINE_VISIBILITY
979    key_equal& key_eq() _NOEXCEPT {return __p3_.second();}
980    _LIBCPP_INLINE_VISIBILITY
981    const key_equal& key_eq() const _NOEXCEPT {return __p3_.second();}
982
983    _LIBCPP_INLINE_VISIBILITY
984    __node_allocator& __node_alloc() _NOEXCEPT {return __p1_.second();}
985    _LIBCPP_INLINE_VISIBILITY
986    const __node_allocator& __node_alloc() const _NOEXCEPT
987        {return __p1_.second();}
988
989public:
990    typedef __hash_iterator<__node_pointer>                   iterator;
991    typedef __hash_const_iterator<__node_pointer>             const_iterator;
992    typedef __hash_local_iterator<__node_pointer>             local_iterator;
993    typedef __hash_const_local_iterator<__node_pointer>       const_local_iterator;
994
995    _LIBCPP_INLINE_VISIBILITY
996    __hash_table()
997        _NOEXCEPT_(
998            is_nothrow_default_constructible<__bucket_list>::value &&
999            is_nothrow_default_constructible<__first_node>::value &&
1000            is_nothrow_default_constructible<__node_allocator>::value &&
1001            is_nothrow_default_constructible<hasher>::value &&
1002            is_nothrow_default_constructible<key_equal>::value);
1003    _LIBCPP_INLINE_VISIBILITY
1004    __hash_table(const hasher& __hf, const key_equal& __eql);
1005    __hash_table(const hasher& __hf, const key_equal& __eql,
1006                 const allocator_type& __a);
1007    explicit __hash_table(const allocator_type& __a);
1008    __hash_table(const __hash_table& __u);
1009    __hash_table(const __hash_table& __u, const allocator_type& __a);
1010#ifndef _LIBCPP_CXX03_LANG
1011    __hash_table(__hash_table&& __u)
1012        _NOEXCEPT_(
1013            is_nothrow_move_constructible<__bucket_list>::value &&
1014            is_nothrow_move_constructible<__first_node>::value &&
1015            is_nothrow_move_constructible<__node_allocator>::value &&
1016            is_nothrow_move_constructible<hasher>::value &&
1017            is_nothrow_move_constructible<key_equal>::value);
1018    __hash_table(__hash_table&& __u, const allocator_type& __a);
1019#endif  // _LIBCPP_CXX03_LANG
1020    ~__hash_table();
1021
1022    __hash_table& operator=(const __hash_table& __u);
1023#ifndef _LIBCPP_CXX03_LANG
1024    _LIBCPP_INLINE_VISIBILITY
1025    __hash_table& operator=(__hash_table&& __u)
1026        _NOEXCEPT_(
1027            __node_traits::propagate_on_container_move_assignment::value &&
1028            is_nothrow_move_assignable<__node_allocator>::value &&
1029            is_nothrow_move_assignable<hasher>::value &&
1030            is_nothrow_move_assignable<key_equal>::value);
1031#endif
1032    template <class _InputIterator>
1033        void __assign_unique(_InputIterator __first, _InputIterator __last);
1034    template <class _InputIterator>
1035        void __assign_multi(_InputIterator __first, _InputIterator __last);
1036
1037    _LIBCPP_INLINE_VISIBILITY
1038    size_type max_size() const _NOEXCEPT
1039    {
1040        return std::min<size_type>(
1041            __node_traits::max_size(__node_alloc()),
1042            numeric_limits<difference_type >::max()
1043        );
1044    }
1045
1046private:
1047    _LIBCPP_INLINE_VISIBILITY
1048    __next_pointer __node_insert_multi_prepare(size_t __cp_hash,
1049                                               value_type& __cp_val);
1050    _LIBCPP_INLINE_VISIBILITY
1051    void __node_insert_multi_perform(__node_pointer __cp,
1052                                     __next_pointer __pn) _NOEXCEPT;
1053
1054    _LIBCPP_INLINE_VISIBILITY
1055    __next_pointer __node_insert_unique_prepare(size_t __nd_hash,
1056                                                value_type& __nd_val);
1057    _LIBCPP_INLINE_VISIBILITY
1058    void __node_insert_unique_perform(__node_pointer __ptr) _NOEXCEPT;
1059
1060public:
1061    _LIBCPP_INLINE_VISIBILITY
1062    pair<iterator, bool> __node_insert_unique(__node_pointer __nd);
1063    _LIBCPP_INLINE_VISIBILITY
1064    iterator             __node_insert_multi(__node_pointer __nd);
1065    _LIBCPP_INLINE_VISIBILITY
1066    iterator             __node_insert_multi(const_iterator __p,
1067                                             __node_pointer __nd);
1068
1069#ifndef _LIBCPP_CXX03_LANG
1070    template <class _Key, class ..._Args>
1071    _LIBCPP_INLINE_VISIBILITY
1072    pair<iterator, bool> __emplace_unique_key_args(_Key const& __k, _Args&&... __args);
1073
1074    template <class... _Args>
1075    _LIBCPP_INLINE_VISIBILITY
1076    pair<iterator, bool> __emplace_unique_impl(_Args&&... __args);
1077
1078    template <class _Pp>
1079    _LIBCPP_INLINE_VISIBILITY
1080    pair<iterator, bool> __emplace_unique(_Pp&& __x) {
1081      return __emplace_unique_extract_key(_VSTD::forward<_Pp>(__x),
1082                                          __can_extract_key<_Pp, key_type>());
1083    }
1084
1085    template <class _First, class _Second>
1086    _LIBCPP_INLINE_VISIBILITY
1087    typename enable_if<
1088        __can_extract_map_key<_First, key_type, __container_value_type>::value,
1089        pair<iterator, bool>
1090    >::type __emplace_unique(_First&& __f, _Second&& __s) {
1091        return __emplace_unique_key_args(__f, _VSTD::forward<_First>(__f),
1092                                              _VSTD::forward<_Second>(__s));
1093    }
1094
1095    template <class... _Args>
1096    _LIBCPP_INLINE_VISIBILITY
1097    pair<iterator, bool> __emplace_unique(_Args&&... __args) {
1098      return __emplace_unique_impl(_VSTD::forward<_Args>(__args)...);
1099    }
1100
1101    template <class _Pp>
1102    _LIBCPP_INLINE_VISIBILITY
1103    pair<iterator, bool>
1104    __emplace_unique_extract_key(_Pp&& __x, __extract_key_fail_tag) {
1105      return __emplace_unique_impl(_VSTD::forward<_Pp>(__x));
1106    }
1107    template <class _Pp>
1108    _LIBCPP_INLINE_VISIBILITY
1109    pair<iterator, bool>
1110    __emplace_unique_extract_key(_Pp&& __x, __extract_key_self_tag) {
1111      return __emplace_unique_key_args(__x, _VSTD::forward<_Pp>(__x));
1112    }
1113    template <class _Pp>
1114    _LIBCPP_INLINE_VISIBILITY
1115    pair<iterator, bool>
1116    __emplace_unique_extract_key(_Pp&& __x, __extract_key_first_tag) {
1117      return __emplace_unique_key_args(__x.first, _VSTD::forward<_Pp>(__x));
1118    }
1119
1120    template <class... _Args>
1121    _LIBCPP_INLINE_VISIBILITY
1122    iterator __emplace_multi(_Args&&... __args);
1123    template <class... _Args>
1124    _LIBCPP_INLINE_VISIBILITY
1125    iterator __emplace_hint_multi(const_iterator __p, _Args&&... __args);
1126
1127
1128    _LIBCPP_INLINE_VISIBILITY
1129    pair<iterator, bool>
1130    __insert_unique(__container_value_type&& __x) {
1131      return __emplace_unique_key_args(_NodeTypes::__get_key(__x), _VSTD::move(__x));
1132    }
1133
1134    template <class _Pp, class = typename enable_if<
1135            !__is_same_uncvref<_Pp, __container_value_type>::value
1136        >::type>
1137    _LIBCPP_INLINE_VISIBILITY
1138    pair<iterator, bool> __insert_unique(_Pp&& __x) {
1139      return __emplace_unique(_VSTD::forward<_Pp>(__x));
1140    }
1141
1142    template <class _Pp>
1143    _LIBCPP_INLINE_VISIBILITY
1144    iterator __insert_multi(_Pp&& __x) {
1145      return __emplace_multi(_VSTD::forward<_Pp>(__x));
1146    }
1147
1148    template <class _Pp>
1149    _LIBCPP_INLINE_VISIBILITY
1150    iterator __insert_multi(const_iterator __p, _Pp&& __x) {
1151        return __emplace_hint_multi(__p, _VSTD::forward<_Pp>(__x));
1152    }
1153
1154#else  // !defined(_LIBCPP_CXX03_LANG)
1155    template <class _Key, class _Args>
1156    _LIBCPP_INLINE_VISIBILITY
1157    pair<iterator, bool> __emplace_unique_key_args(_Key const&, _Args& __args);
1158
1159    iterator __insert_multi(const __container_value_type& __x);
1160    iterator __insert_multi(const_iterator __p, const __container_value_type& __x);
1161#endif
1162
1163    _LIBCPP_INLINE_VISIBILITY
1164    pair<iterator, bool> __insert_unique(const __container_value_type& __x) {
1165        return __emplace_unique_key_args(_NodeTypes::__get_key(__x), __x);
1166    }
1167
1168#if _LIBCPP_STD_VER > 14
1169    template <class _NodeHandle, class _InsertReturnType>
1170    _LIBCPP_INLINE_VISIBILITY
1171    _InsertReturnType __node_handle_insert_unique(_NodeHandle&& __nh);
1172    template <class _NodeHandle>
1173    _LIBCPP_INLINE_VISIBILITY
1174    iterator __node_handle_insert_unique(const_iterator __hint,
1175                                         _NodeHandle&& __nh);
1176    template <class _Table>
1177    _LIBCPP_INLINE_VISIBILITY
1178    void __node_handle_merge_unique(_Table& __source);
1179
1180    template <class _NodeHandle>
1181    _LIBCPP_INLINE_VISIBILITY
1182    iterator __node_handle_insert_multi(_NodeHandle&& __nh);
1183    template <class _NodeHandle>
1184    _LIBCPP_INLINE_VISIBILITY
1185    iterator __node_handle_insert_multi(const_iterator __hint, _NodeHandle&& __nh);
1186    template <class _Table>
1187    _LIBCPP_INLINE_VISIBILITY
1188    void __node_handle_merge_multi(_Table& __source);
1189
1190    template <class _NodeHandle>
1191    _LIBCPP_INLINE_VISIBILITY
1192    _NodeHandle __node_handle_extract(key_type const& __key);
1193    template <class _NodeHandle>
1194    _LIBCPP_INLINE_VISIBILITY
1195    _NodeHandle __node_handle_extract(const_iterator __it);
1196#endif
1197
1198    void clear() _NOEXCEPT;
1199    void rehash(size_type __n);
1200    _LIBCPP_INLINE_VISIBILITY void reserve(size_type __n)
1201        {rehash(static_cast<size_type>(ceil(__n / max_load_factor())));}
1202
1203    _LIBCPP_INLINE_VISIBILITY
1204    size_type bucket_count() const _NOEXCEPT
1205    {
1206        return __bucket_list_.get_deleter().size();
1207    }
1208
1209    _LIBCPP_INLINE_VISIBILITY
1210    iterator       begin() _NOEXCEPT;
1211    _LIBCPP_INLINE_VISIBILITY
1212    iterator       end() _NOEXCEPT;
1213    _LIBCPP_INLINE_VISIBILITY
1214    const_iterator begin() const _NOEXCEPT;
1215    _LIBCPP_INLINE_VISIBILITY
1216    const_iterator end() const _NOEXCEPT;
1217
1218    template <class _Key>
1219        _LIBCPP_INLINE_VISIBILITY
1220        size_type bucket(const _Key& __k) const
1221        {
1222            _LIBCPP_ASSERT(bucket_count() > 0,
1223                "unordered container::bucket(key) called when bucket_count() == 0");
1224            return __constrain_hash(hash_function()(__k), bucket_count());
1225        }
1226
1227    template <class _Key>
1228        iterator       find(const _Key& __x);
1229    template <class _Key>
1230        const_iterator find(const _Key& __x) const;
1231
1232    typedef __hash_node_destructor<__node_allocator> _Dp;
1233    typedef unique_ptr<__node, _Dp> __node_holder;
1234
1235    iterator erase(const_iterator __p);
1236    iterator erase(const_iterator __first, const_iterator __last);
1237    template <class _Key>
1238        size_type __erase_unique(const _Key& __k);
1239    template <class _Key>
1240        size_type __erase_multi(const _Key& __k);
1241    __node_holder remove(const_iterator __p) _NOEXCEPT;
1242
1243    template <class _Key>
1244        _LIBCPP_INLINE_VISIBILITY
1245        size_type __count_unique(const _Key& __k) const;
1246    template <class _Key>
1247        size_type __count_multi(const _Key& __k) const;
1248
1249    template <class _Key>
1250        pair<iterator, iterator>
1251        __equal_range_unique(const _Key& __k);
1252    template <class _Key>
1253        pair<const_iterator, const_iterator>
1254        __equal_range_unique(const _Key& __k) const;
1255
1256    template <class _Key>
1257        pair<iterator, iterator>
1258        __equal_range_multi(const _Key& __k);
1259    template <class _Key>
1260        pair<const_iterator, const_iterator>
1261        __equal_range_multi(const _Key& __k) const;
1262
1263    void swap(__hash_table& __u)
1264#if _LIBCPP_STD_VER <= 11
1265        _NOEXCEPT_(
1266            __is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value
1267            && (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value
1268                  || __is_nothrow_swappable<__pointer_allocator>::value)
1269            && (!__node_traits::propagate_on_container_swap::value
1270                  || __is_nothrow_swappable<__node_allocator>::value)
1271            );
1272#else
1273     _NOEXCEPT_(__is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value);
1274#endif
1275
1276    _LIBCPP_INLINE_VISIBILITY
1277    size_type max_bucket_count() const _NOEXCEPT
1278        {return max_size(); }
1279    size_type bucket_size(size_type __n) const;
1280    _LIBCPP_INLINE_VISIBILITY float load_factor() const _NOEXCEPT
1281    {
1282        size_type __bc = bucket_count();
1283        return __bc != 0 ? (float)size() / __bc : 0.f;
1284    }
1285    _LIBCPP_INLINE_VISIBILITY void max_load_factor(float __mlf) _NOEXCEPT
1286    {
1287        _LIBCPP_ASSERT(__mlf > 0,
1288            "unordered container::max_load_factor(lf) called with lf <= 0");
1289        max_load_factor() = _VSTD::max(__mlf, load_factor());
1290    }
1291
1292    _LIBCPP_INLINE_VISIBILITY
1293    local_iterator
1294    begin(size_type __n)
1295    {
1296        _LIBCPP_ASSERT(__n < bucket_count(),
1297            "unordered container::begin(n) called with n >= bucket_count()");
1298#if _LIBCPP_DEBUG_LEVEL >= 2
1299        return local_iterator(__bucket_list_[__n], __n, bucket_count(), this);
1300#else
1301        return local_iterator(__bucket_list_[__n], __n, bucket_count());
1302#endif
1303    }
1304
1305    _LIBCPP_INLINE_VISIBILITY
1306    local_iterator
1307    end(size_type __n)
1308    {
1309        _LIBCPP_ASSERT(__n < bucket_count(),
1310            "unordered container::end(n) called with n >= bucket_count()");
1311#if _LIBCPP_DEBUG_LEVEL >= 2
1312        return local_iterator(nullptr, __n, bucket_count(), this);
1313#else
1314        return local_iterator(nullptr, __n, bucket_count());
1315#endif
1316    }
1317
1318    _LIBCPP_INLINE_VISIBILITY
1319    const_local_iterator
1320    cbegin(size_type __n) const
1321    {
1322        _LIBCPP_ASSERT(__n < bucket_count(),
1323            "unordered container::cbegin(n) called with n >= bucket_count()");
1324#if _LIBCPP_DEBUG_LEVEL >= 2
1325        return const_local_iterator(__bucket_list_[__n], __n, bucket_count(), this);
1326#else
1327        return const_local_iterator(__bucket_list_[__n], __n, bucket_count());
1328#endif
1329    }
1330
1331    _LIBCPP_INLINE_VISIBILITY
1332    const_local_iterator
1333    cend(size_type __n) const
1334    {
1335        _LIBCPP_ASSERT(__n < bucket_count(),
1336            "unordered container::cend(n) called with n >= bucket_count()");
1337#if _LIBCPP_DEBUG_LEVEL >= 2
1338        return const_local_iterator(nullptr, __n, bucket_count(), this);
1339#else
1340        return const_local_iterator(nullptr, __n, bucket_count());
1341#endif
1342    }
1343
1344#if _LIBCPP_DEBUG_LEVEL >= 2
1345
1346    bool __dereferenceable(const const_iterator* __i) const;
1347    bool __decrementable(const const_iterator* __i) const;
1348    bool __addable(const const_iterator* __i, ptrdiff_t __n) const;
1349    bool __subscriptable(const const_iterator* __i, ptrdiff_t __n) const;
1350
1351#endif  // _LIBCPP_DEBUG_LEVEL >= 2
1352
1353private:
1354    void __rehash(size_type __n);
1355
1356#ifndef _LIBCPP_CXX03_LANG
1357    template <class ..._Args>
1358    __node_holder __construct_node(_Args&& ...__args);
1359
1360    template <class _First, class ..._Rest>
1361    __node_holder __construct_node_hash(size_t __hash, _First&& __f, _Rest&&... __rest);
1362#else // _LIBCPP_CXX03_LANG
1363    __node_holder __construct_node(const __container_value_type& __v);
1364    __node_holder __construct_node_hash(size_t __hash, const __container_value_type& __v);
1365#endif
1366
1367
1368    _LIBCPP_INLINE_VISIBILITY
1369    void __copy_assign_alloc(const __hash_table& __u)
1370        {__copy_assign_alloc(__u, integral_constant<bool,
1371             __node_traits::propagate_on_container_copy_assignment::value>());}
1372    void __copy_assign_alloc(const __hash_table& __u, true_type);
1373    _LIBCPP_INLINE_VISIBILITY
1374        void __copy_assign_alloc(const __hash_table&, false_type) {}
1375
1376#ifndef _LIBCPP_CXX03_LANG
1377    void __move_assign(__hash_table& __u, false_type);
1378    void __move_assign(__hash_table& __u, true_type)
1379        _NOEXCEPT_(
1380            is_nothrow_move_assignable<__node_allocator>::value &&
1381            is_nothrow_move_assignable<hasher>::value &&
1382            is_nothrow_move_assignable<key_equal>::value);
1383    _LIBCPP_INLINE_VISIBILITY
1384    void __move_assign_alloc(__hash_table& __u)
1385        _NOEXCEPT_(
1386            !__node_traits::propagate_on_container_move_assignment::value ||
1387            (is_nothrow_move_assignable<__pointer_allocator>::value &&
1388             is_nothrow_move_assignable<__node_allocator>::value))
1389        {__move_assign_alloc(__u, integral_constant<bool,
1390             __node_traits::propagate_on_container_move_assignment::value>());}
1391    _LIBCPP_INLINE_VISIBILITY
1392    void __move_assign_alloc(__hash_table& __u, true_type)
1393        _NOEXCEPT_(
1394            is_nothrow_move_assignable<__pointer_allocator>::value &&
1395            is_nothrow_move_assignable<__node_allocator>::value)
1396    {
1397        __bucket_list_.get_deleter().__alloc() =
1398                _VSTD::move(__u.__bucket_list_.get_deleter().__alloc());
1399        __node_alloc() = _VSTD::move(__u.__node_alloc());
1400    }
1401    _LIBCPP_INLINE_VISIBILITY
1402        void __move_assign_alloc(__hash_table&, false_type) _NOEXCEPT {}
1403#endif // _LIBCPP_CXX03_LANG
1404
1405    void __deallocate_node(__next_pointer __np) _NOEXCEPT;
1406    __next_pointer __detach() _NOEXCEPT;
1407
1408    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_map;
1409    template <class, class, class, class, class> friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
1410};
1411
1412template <class _Tp, class _Hash, class _Equal, class _Alloc>
1413inline
1414__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table()
1415    _NOEXCEPT_(
1416        is_nothrow_default_constructible<__bucket_list>::value &&
1417        is_nothrow_default_constructible<__first_node>::value &&
1418        is_nothrow_default_constructible<__node_allocator>::value &&
1419        is_nothrow_default_constructible<hasher>::value &&
1420        is_nothrow_default_constructible<key_equal>::value)
1421    : __p2_(0),
1422      __p3_(1.0f)
1423{
1424}
1425
1426template <class _Tp, class _Hash, class _Equal, class _Alloc>
1427inline
1428__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const hasher& __hf,
1429                                                       const key_equal& __eql)
1430    : __bucket_list_(nullptr, __bucket_list_deleter()),
1431      __p1_(),
1432      __p2_(0, __hf),
1433      __p3_(1.0f, __eql)
1434{
1435}
1436
1437template <class _Tp, class _Hash, class _Equal, class _Alloc>
1438__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const hasher& __hf,
1439                                                       const key_equal& __eql,
1440                                                       const allocator_type& __a)
1441    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1442      __p1_(__second_tag(), __node_allocator(__a)),
1443      __p2_(0, __hf),
1444      __p3_(1.0f, __eql)
1445{
1446}
1447
1448template <class _Tp, class _Hash, class _Equal, class _Alloc>
1449__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const allocator_type& __a)
1450    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1451      __p1_(__second_tag(), __node_allocator(__a)),
1452      __p2_(0),
1453      __p3_(1.0f)
1454{
1455}
1456
1457template <class _Tp, class _Hash, class _Equal, class _Alloc>
1458__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u)
1459    : __bucket_list_(nullptr,
1460          __bucket_list_deleter(allocator_traits<__pointer_allocator>::
1461              select_on_container_copy_construction(
1462                  __u.__bucket_list_.get_deleter().__alloc()), 0)),
1463      __p1_(__second_tag(), allocator_traits<__node_allocator>::
1464          select_on_container_copy_construction(__u.__node_alloc())),
1465      __p2_(0, __u.hash_function()),
1466      __p3_(__u.__p3_)
1467{
1468}
1469
1470template <class _Tp, class _Hash, class _Equal, class _Alloc>
1471__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u,
1472                                                       const allocator_type& __a)
1473    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1474      __p1_(__second_tag(), __node_allocator(__a)),
1475      __p2_(0, __u.hash_function()),
1476      __p3_(__u.__p3_)
1477{
1478}
1479
1480#ifndef _LIBCPP_CXX03_LANG
1481
1482template <class _Tp, class _Hash, class _Equal, class _Alloc>
1483__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u)
1484        _NOEXCEPT_(
1485            is_nothrow_move_constructible<__bucket_list>::value &&
1486            is_nothrow_move_constructible<__first_node>::value &&
1487            is_nothrow_move_constructible<__node_allocator>::value &&
1488            is_nothrow_move_constructible<hasher>::value &&
1489            is_nothrow_move_constructible<key_equal>::value)
1490    : __bucket_list_(_VSTD::move(__u.__bucket_list_)),
1491      __p1_(_VSTD::move(__u.__p1_)),
1492      __p2_(_VSTD::move(__u.__p2_)),
1493      __p3_(_VSTD::move(__u.__p3_))
1494{
1495    if (size() > 0)
1496    {
1497        __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
1498            __p1_.first().__ptr();
1499        __u.__p1_.first().__next_ = nullptr;
1500        __u.size() = 0;
1501    }
1502}
1503
1504template <class _Tp, class _Hash, class _Equal, class _Alloc>
1505__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u,
1506                                                       const allocator_type& __a)
1507    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1508      __p1_(__second_tag(), __node_allocator(__a)),
1509      __p2_(0, _VSTD::move(__u.hash_function())),
1510      __p3_(_VSTD::move(__u.__p3_))
1511{
1512    if (__a == allocator_type(__u.__node_alloc()))
1513    {
1514        __bucket_list_.reset(__u.__bucket_list_.release());
1515        __bucket_list_.get_deleter().size() = __u.__bucket_list_.get_deleter().size();
1516        __u.__bucket_list_.get_deleter().size() = 0;
1517        if (__u.size() > 0)
1518        {
1519            __p1_.first().__next_ = __u.__p1_.first().__next_;
1520            __u.__p1_.first().__next_ = nullptr;
1521            __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
1522                __p1_.first().__ptr();
1523            size() = __u.size();
1524            __u.size() = 0;
1525        }
1526    }
1527}
1528
1529#endif  // _LIBCPP_CXX03_LANG
1530
1531template <class _Tp, class _Hash, class _Equal, class _Alloc>
1532__hash_table<_Tp, _Hash, _Equal, _Alloc>::~__hash_table()
1533{
1534#if defined(_LIBCPP_CXX03_LANG)
1535    static_assert((is_copy_constructible<key_equal>::value),
1536                 "Predicate must be copy-constructible.");
1537    static_assert((is_copy_constructible<hasher>::value),
1538                 "Hasher must be copy-constructible.");
1539#endif
1540
1541    __deallocate_node(__p1_.first().__next_);
1542#if _LIBCPP_DEBUG_LEVEL >= 2
1543    __get_db()->__erase_c(this);
1544#endif
1545}
1546
1547template <class _Tp, class _Hash, class _Equal, class _Alloc>
1548void
1549__hash_table<_Tp, _Hash, _Equal, _Alloc>::__copy_assign_alloc(
1550        const __hash_table& __u, true_type)
1551{
1552    if (__node_alloc() != __u.__node_alloc())
1553    {
1554        clear();
1555        __bucket_list_.reset();
1556        __bucket_list_.get_deleter().size() = 0;
1557    }
1558    __bucket_list_.get_deleter().__alloc() = __u.__bucket_list_.get_deleter().__alloc();
1559    __node_alloc() = __u.__node_alloc();
1560}
1561
1562template <class _Tp, class _Hash, class _Equal, class _Alloc>
1563__hash_table<_Tp, _Hash, _Equal, _Alloc>&
1564__hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(const __hash_table& __u)
1565{
1566    if (this != &__u)
1567    {
1568        __copy_assign_alloc(__u);
1569        hash_function() = __u.hash_function();
1570        key_eq() = __u.key_eq();
1571        max_load_factor() = __u.max_load_factor();
1572        __assign_multi(__u.begin(), __u.end());
1573    }
1574    return *this;
1575}
1576
1577template <class _Tp, class _Hash, class _Equal, class _Alloc>
1578void
1579__hash_table<_Tp, _Hash, _Equal, _Alloc>::__deallocate_node(__next_pointer __np)
1580    _NOEXCEPT
1581{
1582    __node_allocator& __na = __node_alloc();
1583    while (__np != nullptr)
1584    {
1585        __next_pointer __next = __np->__next_;
1586#if _LIBCPP_DEBUG_LEVEL >= 2
1587        __c_node* __c = __get_db()->__find_c_and_lock(this);
1588        for (__i_node** __p = __c->end_; __p != __c->beg_; )
1589        {
1590            --__p;
1591            iterator* __i = static_cast<iterator*>((*__p)->__i_);
1592            if (__i->__node_ == __np)
1593            {
1594                (*__p)->__c_ = nullptr;
1595                if (--__c->end_ != __p)
1596                    memmove(__p, __p+1, (__c->end_ - __p)*sizeof(__i_node*));
1597            }
1598        }
1599        __get_db()->unlock();
1600#endif
1601        __node_pointer __real_np = __np->__upcast();
1602        __node_traits::destroy(__na, _NodeTypes::__get_ptr(__real_np->__value_));
1603        __node_traits::deallocate(__na, __real_np, 1);
1604        __np = __next;
1605    }
1606}
1607
1608template <class _Tp, class _Hash, class _Equal, class _Alloc>
1609typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1610__hash_table<_Tp, _Hash, _Equal, _Alloc>::__detach() _NOEXCEPT
1611{
1612    size_type __bc = bucket_count();
1613    for (size_type __i = 0; __i < __bc; ++__i)
1614        __bucket_list_[__i] = nullptr;
1615    size() = 0;
1616    __next_pointer __cache = __p1_.first().__next_;
1617    __p1_.first().__next_ = nullptr;
1618    return __cache;
1619}
1620
1621#ifndef _LIBCPP_CXX03_LANG
1622
1623template <class _Tp, class _Hash, class _Equal, class _Alloc>
1624void
1625__hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(
1626        __hash_table& __u, true_type)
1627    _NOEXCEPT_(
1628        is_nothrow_move_assignable<__node_allocator>::value &&
1629        is_nothrow_move_assignable<hasher>::value &&
1630        is_nothrow_move_assignable<key_equal>::value)
1631{
1632    clear();
1633    __bucket_list_.reset(__u.__bucket_list_.release());
1634    __bucket_list_.get_deleter().size() = __u.__bucket_list_.get_deleter().size();
1635    __u.__bucket_list_.get_deleter().size() = 0;
1636    __move_assign_alloc(__u);
1637    size() = __u.size();
1638    hash_function() = _VSTD::move(__u.hash_function());
1639    max_load_factor() = __u.max_load_factor();
1640    key_eq() = _VSTD::move(__u.key_eq());
1641    __p1_.first().__next_ = __u.__p1_.first().__next_;
1642    if (size() > 0)
1643    {
1644        __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
1645            __p1_.first().__ptr();
1646        __u.__p1_.first().__next_ = nullptr;
1647        __u.size() = 0;
1648    }
1649#if _LIBCPP_DEBUG_LEVEL >= 2
1650    __get_db()->swap(this, &__u);
1651#endif
1652}
1653
1654template <class _Tp, class _Hash, class _Equal, class _Alloc>
1655void
1656__hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(
1657        __hash_table& __u, false_type)
1658{
1659    if (__node_alloc() == __u.__node_alloc())
1660        __move_assign(__u, true_type());
1661    else
1662    {
1663        hash_function() = _VSTD::move(__u.hash_function());
1664        key_eq() = _VSTD::move(__u.key_eq());
1665        max_load_factor() = __u.max_load_factor();
1666        if (bucket_count() != 0)
1667        {
1668            __next_pointer __cache = __detach();
1669#ifndef _LIBCPP_NO_EXCEPTIONS
1670            try
1671            {
1672#endif  // _LIBCPP_NO_EXCEPTIONS
1673                const_iterator __i = __u.begin();
1674                while (__cache != nullptr && __u.size() != 0)
1675                {
1676                    __cache->__upcast()->__value_ =
1677                        _VSTD::move(__u.remove(__i++)->__value_);
1678                    __next_pointer __next = __cache->__next_;
1679                    __node_insert_multi(__cache->__upcast());
1680                    __cache = __next;
1681                }
1682#ifndef _LIBCPP_NO_EXCEPTIONS
1683            }
1684            catch (...)
1685            {
1686                __deallocate_node(__cache);
1687                throw;
1688            }
1689#endif  // _LIBCPP_NO_EXCEPTIONS
1690            __deallocate_node(__cache);
1691        }
1692        const_iterator __i = __u.begin();
1693        while (__u.size() != 0)
1694        {
1695            __node_holder __h = __construct_node(_NodeTypes::__move(__u.remove(__i++)->__value_));
1696            __node_insert_multi(__h.get());
1697            __h.release();
1698        }
1699    }
1700}
1701
1702template <class _Tp, class _Hash, class _Equal, class _Alloc>
1703inline
1704__hash_table<_Tp, _Hash, _Equal, _Alloc>&
1705__hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(__hash_table&& __u)
1706    _NOEXCEPT_(
1707        __node_traits::propagate_on_container_move_assignment::value &&
1708        is_nothrow_move_assignable<__node_allocator>::value &&
1709        is_nothrow_move_assignable<hasher>::value &&
1710        is_nothrow_move_assignable<key_equal>::value)
1711{
1712    __move_assign(__u, integral_constant<bool,
1713                  __node_traits::propagate_on_container_move_assignment::value>());
1714    return *this;
1715}
1716
1717#endif  // _LIBCPP_CXX03_LANG
1718
1719template <class _Tp, class _Hash, class _Equal, class _Alloc>
1720template <class _InputIterator>
1721void
1722__hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_unique(_InputIterator __first,
1723                                                          _InputIterator __last)
1724{
1725    typedef iterator_traits<_InputIterator> _ITraits;
1726    typedef typename _ITraits::value_type _ItValueType;
1727    static_assert((is_same<_ItValueType, __container_value_type>::value),
1728                  "__assign_unique may only be called with the containers value type");
1729
1730    if (bucket_count() != 0)
1731    {
1732        __next_pointer __cache = __detach();
1733#ifndef _LIBCPP_NO_EXCEPTIONS
1734        try
1735        {
1736#endif  // _LIBCPP_NO_EXCEPTIONS
1737            for (; __cache != nullptr && __first != __last; ++__first)
1738            {
1739                __cache->__upcast()->__value_ = *__first;
1740                __next_pointer __next = __cache->__next_;
1741                __node_insert_unique(__cache->__upcast());
1742                __cache = __next;
1743            }
1744#ifndef _LIBCPP_NO_EXCEPTIONS
1745        }
1746        catch (...)
1747        {
1748            __deallocate_node(__cache);
1749            throw;
1750        }
1751#endif  // _LIBCPP_NO_EXCEPTIONS
1752        __deallocate_node(__cache);
1753    }
1754    for (; __first != __last; ++__first)
1755        __insert_unique(*__first);
1756}
1757
1758template <class _Tp, class _Hash, class _Equal, class _Alloc>
1759template <class _InputIterator>
1760void
1761__hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_multi(_InputIterator __first,
1762                                                         _InputIterator __last)
1763{
1764    typedef iterator_traits<_InputIterator> _ITraits;
1765    typedef typename _ITraits::value_type _ItValueType;
1766    static_assert((is_same<_ItValueType, __container_value_type>::value ||
1767                  is_same<_ItValueType, __node_value_type>::value),
1768                  "__assign_multi may only be called with the containers value type"
1769                  " or the nodes value type");
1770    if (bucket_count() != 0)
1771    {
1772        __next_pointer __cache = __detach();
1773#ifndef _LIBCPP_NO_EXCEPTIONS
1774        try
1775        {
1776#endif  // _LIBCPP_NO_EXCEPTIONS
1777            for (; __cache != nullptr && __first != __last; ++__first)
1778            {
1779                __cache->__upcast()->__value_ = *__first;
1780                __next_pointer __next = __cache->__next_;
1781                __node_insert_multi(__cache->__upcast());
1782                __cache = __next;
1783            }
1784#ifndef _LIBCPP_NO_EXCEPTIONS
1785        }
1786        catch (...)
1787        {
1788            __deallocate_node(__cache);
1789            throw;
1790        }
1791#endif  // _LIBCPP_NO_EXCEPTIONS
1792        __deallocate_node(__cache);
1793    }
1794    for (; __first != __last; ++__first)
1795        __insert_multi(_NodeTypes::__get_value(*__first));
1796}
1797
1798template <class _Tp, class _Hash, class _Equal, class _Alloc>
1799inline
1800typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1801__hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() _NOEXCEPT
1802{
1803#if _LIBCPP_DEBUG_LEVEL >= 2
1804    return iterator(__p1_.first().__next_, this);
1805#else
1806    return iterator(__p1_.first().__next_);
1807#endif
1808}
1809
1810template <class _Tp, class _Hash, class _Equal, class _Alloc>
1811inline
1812typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1813__hash_table<_Tp, _Hash, _Equal, _Alloc>::end() _NOEXCEPT
1814{
1815#if _LIBCPP_DEBUG_LEVEL >= 2
1816    return iterator(nullptr, this);
1817#else
1818    return iterator(nullptr);
1819#endif
1820}
1821
1822template <class _Tp, class _Hash, class _Equal, class _Alloc>
1823inline
1824typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
1825__hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() const _NOEXCEPT
1826{
1827#if _LIBCPP_DEBUG_LEVEL >= 2
1828    return const_iterator(__p1_.first().__next_, this);
1829#else
1830    return const_iterator(__p1_.first().__next_);
1831#endif
1832}
1833
1834template <class _Tp, class _Hash, class _Equal, class _Alloc>
1835inline
1836typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
1837__hash_table<_Tp, _Hash, _Equal, _Alloc>::end() const _NOEXCEPT
1838{
1839#if _LIBCPP_DEBUG_LEVEL >= 2
1840    return const_iterator(nullptr, this);
1841#else
1842    return const_iterator(nullptr);
1843#endif
1844}
1845
1846template <class _Tp, class _Hash, class _Equal, class _Alloc>
1847void
1848__hash_table<_Tp, _Hash, _Equal, _Alloc>::clear() _NOEXCEPT
1849{
1850    if (size() > 0)
1851    {
1852        __deallocate_node(__p1_.first().__next_);
1853        __p1_.first().__next_ = nullptr;
1854        size_type __bc = bucket_count();
1855        for (size_type __i = 0; __i < __bc; ++__i)
1856            __bucket_list_[__i] = nullptr;
1857        size() = 0;
1858    }
1859}
1860
1861
1862// Prepare the container for an insertion of the value __value with the hash
1863// __hash. This does a lookup into the container to see if __value is already
1864// present, and performs a rehash if necessary. Returns a pointer to the
1865// existing element if it exists, otherwise nullptr.
1866//
1867// Note that this function does forward exceptions if key_eq() throws, and never
1868// mutates __value or actually inserts into the map.
1869template <class _Tp, class _Hash, class _Equal, class _Alloc>
1870_LIBCPP_INLINE_VISIBILITY
1871typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1872__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique_prepare(
1873    size_t __hash, value_type& __value)
1874{
1875    size_type __bc = bucket_count();
1876
1877    if (__bc != 0)
1878    {
1879        size_t __chash = __constrain_hash(__hash, __bc);
1880        __next_pointer __ndptr = __bucket_list_[__chash];
1881        if (__ndptr != nullptr)
1882        {
1883            for (__ndptr = __ndptr->__next_; __ndptr != nullptr &&
1884                                             __constrain_hash(__ndptr->__hash(), __bc) == __chash;
1885                                                     __ndptr = __ndptr->__next_)
1886            {
1887                if (key_eq()(__ndptr->__upcast()->__value_, __value))
1888                    return __ndptr;
1889            }
1890        }
1891    }
1892    if (size()+1 > __bc * max_load_factor() || __bc == 0)
1893    {
1894        rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
1895                                     size_type(ceil(float(size() + 1) / max_load_factor()))));
1896    }
1897    return nullptr;
1898}
1899
1900// Insert the node __nd into the container by pushing it into the right bucket,
1901// and updating size(). Assumes that __nd->__hash is up-to-date, and that
1902// rehashing has already occurred and that no element with the same key exists
1903// in the map.
1904template <class _Tp, class _Hash, class _Equal, class _Alloc>
1905_LIBCPP_INLINE_VISIBILITY
1906void
1907__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique_perform(
1908    __node_pointer __nd) _NOEXCEPT
1909{
1910    size_type __bc = bucket_count();
1911    size_t __chash = __constrain_hash(__nd->__hash(), __bc);
1912    // insert_after __bucket_list_[__chash], or __first_node if bucket is null
1913    __next_pointer __pn = __bucket_list_[__chash];
1914    if (__pn == nullptr)
1915    {
1916        __pn =__p1_.first().__ptr();
1917        __nd->__next_ = __pn->__next_;
1918        __pn->__next_ = __nd->__ptr();
1919        // fix up __bucket_list_
1920        __bucket_list_[__chash] = __pn;
1921        if (__nd->__next_ != nullptr)
1922            __bucket_list_[__constrain_hash(__nd->__next_->__hash(), __bc)] = __nd->__ptr();
1923    }
1924    else
1925    {
1926        __nd->__next_ = __pn->__next_;
1927        __pn->__next_ = __nd->__ptr();
1928    }
1929    ++size();
1930}
1931
1932template <class _Tp, class _Hash, class _Equal, class _Alloc>
1933pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
1934__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique(__node_pointer __nd)
1935{
1936    __nd->__hash_ = hash_function()(__nd->__value_);
1937    __next_pointer __existing_node =
1938        __node_insert_unique_prepare(__nd->__hash(), __nd->__value_);
1939
1940    // Insert the node, unless it already exists in the container.
1941    bool __inserted = false;
1942    if (__existing_node == nullptr)
1943    {
1944        __node_insert_unique_perform(__nd);
1945        __existing_node = __nd->__ptr();
1946        __inserted = true;
1947    }
1948#if _LIBCPP_DEBUG_LEVEL >= 2
1949    return pair<iterator, bool>(iterator(__existing_node, this), __inserted);
1950#else
1951    return pair<iterator, bool>(iterator(__existing_node), __inserted);
1952#endif
1953}
1954
1955// Prepare the container for an insertion of the value __cp_val with the hash
1956// __cp_hash. This does a lookup into the container to see if __cp_value is
1957// already present, and performs a rehash if necessary. Returns a pointer to the
1958// last occurance of __cp_val in the map.
1959//
1960// Note that this function does forward exceptions if key_eq() throws, and never
1961// mutates __value or actually inserts into the map.
1962template <class _Tp, class _Hash, class _Equal, class _Alloc>
1963typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1964__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi_prepare(
1965    size_t __cp_hash, value_type& __cp_val)
1966{
1967    size_type __bc = bucket_count();
1968    if (size()+1 > __bc * max_load_factor() || __bc == 0)
1969    {
1970        rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
1971                       size_type(ceil(float(size() + 1) / max_load_factor()))));
1972        __bc = bucket_count();
1973    }
1974    size_t __chash = __constrain_hash(__cp_hash, __bc);
1975    __next_pointer __pn = __bucket_list_[__chash];
1976    if (__pn != nullptr)
1977    {
1978        for (bool __found = false; __pn->__next_ != nullptr &&
1979                                   __constrain_hash(__pn->__next_->__hash(), __bc) == __chash;
1980                                                           __pn = __pn->__next_)
1981        {
1982            //      __found    key_eq()     action
1983            //      false       false       loop
1984            //      true        true        loop
1985            //      false       true        set __found to true
1986            //      true        false       break
1987            if (__found != (__pn->__next_->__hash() == __cp_hash &&
1988                            key_eq()(__pn->__next_->__upcast()->__value_, __cp_val)))
1989            {
1990                if (!__found)
1991                    __found = true;
1992                else
1993                    break;
1994            }
1995        }
1996    }
1997    return __pn;
1998}
1999
2000// Insert the node __cp into the container after __pn (which is the last node in
2001// the bucket that compares equal to __cp). Rehashing, and checking for
2002// uniqueness has already been performed (in __node_insert_multi_prepare), so
2003// all we need to do is update the bucket and size(). Assumes that __cp->__hash
2004// is up-to-date.
2005template <class _Tp, class _Hash, class _Equal, class _Alloc>
2006void
2007__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi_perform(
2008    __node_pointer __cp, __next_pointer __pn) _NOEXCEPT
2009{
2010    size_type __bc = bucket_count();
2011    size_t __chash = __constrain_hash(__cp->__hash_, __bc);
2012    if (__pn == nullptr)
2013    {
2014        __pn =__p1_.first().__ptr();
2015        __cp->__next_ = __pn->__next_;
2016        __pn->__next_ = __cp->__ptr();
2017        // fix up __bucket_list_
2018        __bucket_list_[__chash] = __pn;
2019        if (__cp->__next_ != nullptr)
2020            __bucket_list_[__constrain_hash(__cp->__next_->__hash(), __bc)]
2021                = __cp->__ptr();
2022    }
2023    else
2024    {
2025        __cp->__next_ = __pn->__next_;
2026        __pn->__next_ = __cp->__ptr();
2027        if (__cp->__next_ != nullptr)
2028        {
2029            size_t __nhash = __constrain_hash(__cp->__next_->__hash(), __bc);
2030            if (__nhash != __chash)
2031                __bucket_list_[__nhash] = __cp->__ptr();
2032        }
2033    }
2034    ++size();
2035}
2036
2037
2038template <class _Tp, class _Hash, class _Equal, class _Alloc>
2039typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2040__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(__node_pointer __cp)
2041{
2042    __cp->__hash_ = hash_function()(__cp->__value_);
2043    __next_pointer __pn = __node_insert_multi_prepare(__cp->__hash(), __cp->__value_);
2044    __node_insert_multi_perform(__cp, __pn);
2045
2046#if _LIBCPP_DEBUG_LEVEL >= 2
2047    return iterator(__cp->__ptr(), this);
2048#else
2049    return iterator(__cp->__ptr());
2050#endif
2051}
2052
2053template <class _Tp, class _Hash, class _Equal, class _Alloc>
2054typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2055__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(
2056        const_iterator __p, __node_pointer __cp)
2057{
2058#if _LIBCPP_DEBUG_LEVEL >= 2
2059    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
2060        "unordered container::emplace_hint(const_iterator, args...) called with an iterator not"
2061        " referring to this unordered container");
2062#endif
2063    if (__p != end() && key_eq()(*__p, __cp->__value_))
2064    {
2065        __next_pointer __np = __p.__node_;
2066        __cp->__hash_ = __np->__hash();
2067        size_type __bc = bucket_count();
2068        if (size()+1 > __bc * max_load_factor() || __bc == 0)
2069        {
2070            rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
2071                           size_type(ceil(float(size() + 1) / max_load_factor()))));
2072            __bc = bucket_count();
2073        }
2074        size_t __chash = __constrain_hash(__cp->__hash_, __bc);
2075        __next_pointer __pp = __bucket_list_[__chash];
2076        while (__pp->__next_ != __np)
2077            __pp = __pp->__next_;
2078        __cp->__next_ = __np;
2079        __pp->__next_ = static_cast<__next_pointer>(__cp);
2080        ++size();
2081#if _LIBCPP_DEBUG_LEVEL >= 2
2082        return iterator(static_cast<__next_pointer>(__cp), this);
2083#else
2084        return iterator(static_cast<__next_pointer>(__cp));
2085#endif
2086    }
2087    return __node_insert_multi(__cp);
2088}
2089
2090
2091
2092#ifndef _LIBCPP_CXX03_LANG
2093template <class _Tp, class _Hash, class _Equal, class _Alloc>
2094template <class _Key, class ..._Args>
2095pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
2096__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const& __k, _Args&&... __args)
2097#else
2098template <class _Tp, class _Hash, class _Equal, class _Alloc>
2099template <class _Key, class _Args>
2100pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
2101__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const& __k, _Args& __args)
2102#endif
2103{
2104
2105    size_t __hash = hash_function()(__k);
2106    size_type __bc = bucket_count();
2107    bool __inserted = false;
2108    __next_pointer __nd;
2109    size_t __chash;
2110    if (__bc != 0)
2111    {
2112        __chash = __constrain_hash(__hash, __bc);
2113        __nd = __bucket_list_[__chash];
2114        if (__nd != nullptr)
2115        {
2116            for (__nd = __nd->__next_; __nd != nullptr &&
2117                (__nd->__hash() == __hash || __constrain_hash(__nd->__hash(), __bc) == __chash);
2118                                                           __nd = __nd->__next_)
2119            {
2120                if (key_eq()(__nd->__upcast()->__value_, __k))
2121                    goto __done;
2122            }
2123        }
2124    }
2125    {
2126#ifndef _LIBCPP_CXX03_LANG
2127        __node_holder __h = __construct_node_hash(__hash, _VSTD::forward<_Args>(__args)...);
2128#else
2129        __node_holder __h = __construct_node_hash(__hash, __args);
2130#endif
2131        if (size()+1 > __bc * max_load_factor() || __bc == 0)
2132        {
2133            rehash(_VSTD::max<size_type>(2 * __bc + !__is_hash_power2(__bc),
2134                           size_type(ceil(float(size() + 1) / max_load_factor()))));
2135            __bc = bucket_count();
2136            __chash = __constrain_hash(__hash, __bc);
2137        }
2138        // insert_after __bucket_list_[__chash], or __first_node if bucket is null
2139        __next_pointer __pn = __bucket_list_[__chash];
2140        if (__pn == nullptr)
2141        {
2142            __pn = __p1_.first().__ptr();
2143            __h->__next_ = __pn->__next_;
2144            __pn->__next_ = __h.get()->__ptr();
2145            // fix up __bucket_list_
2146            __bucket_list_[__chash] = __pn;
2147            if (__h->__next_ != nullptr)
2148                __bucket_list_[__constrain_hash(__h->__next_->__hash(), __bc)]
2149                    = __h.get()->__ptr();
2150        }
2151        else
2152        {
2153            __h->__next_ = __pn->__next_;
2154            __pn->__next_ = static_cast<__next_pointer>(__h.get());
2155        }
2156        __nd = static_cast<__next_pointer>(__h.release());
2157        // increment size
2158        ++size();
2159        __inserted = true;
2160    }
2161__done:
2162#if _LIBCPP_DEBUG_LEVEL >= 2
2163    return pair<iterator, bool>(iterator(__nd, this), __inserted);
2164#else
2165    return pair<iterator, bool>(iterator(__nd), __inserted);
2166#endif
2167}
2168
2169#ifndef _LIBCPP_CXX03_LANG
2170
2171template <class _Tp, class _Hash, class _Equal, class _Alloc>
2172template <class... _Args>
2173pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
2174__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_impl(_Args&&... __args)
2175{
2176    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
2177    pair<iterator, bool> __r = __node_insert_unique(__h.get());
2178    if (__r.second)
2179        __h.release();
2180    return __r;
2181}
2182
2183template <class _Tp, class _Hash, class _Equal, class _Alloc>
2184template <class... _Args>
2185typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2186__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_multi(_Args&&... __args)
2187{
2188    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
2189    iterator __r = __node_insert_multi(__h.get());
2190    __h.release();
2191    return __r;
2192}
2193
2194template <class _Tp, class _Hash, class _Equal, class _Alloc>
2195template <class... _Args>
2196typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2197__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_hint_multi(
2198        const_iterator __p, _Args&&... __args)
2199{
2200#if _LIBCPP_DEBUG_LEVEL >= 2
2201    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
2202        "unordered container::emplace_hint(const_iterator, args...) called with an iterator not"
2203        " referring to this unordered container");
2204#endif
2205    __node_holder __h = __construct_node(_VSTD::forward<_Args>(__args)...);
2206    iterator __r = __node_insert_multi(__p, __h.get());
2207    __h.release();
2208    return __r;
2209}
2210
2211#else // _LIBCPP_CXX03_LANG
2212
2213template <class _Tp, class _Hash, class _Equal, class _Alloc>
2214typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2215__hash_table<_Tp, _Hash, _Equal, _Alloc>::__insert_multi(const __container_value_type& __x)
2216{
2217    __node_holder __h = __construct_node(__x);
2218    iterator __r = __node_insert_multi(__h.get());
2219    __h.release();
2220    return __r;
2221}
2222
2223template <class _Tp, class _Hash, class _Equal, class _Alloc>
2224typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2225__hash_table<_Tp, _Hash, _Equal, _Alloc>::__insert_multi(const_iterator __p,
2226                                                         const __container_value_type& __x)
2227{
2228#if _LIBCPP_DEBUG_LEVEL >= 2
2229    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
2230        "unordered container::insert(const_iterator, lvalue) called with an iterator not"
2231        " referring to this unordered container");
2232#endif
2233    __node_holder __h = __construct_node(__x);
2234    iterator __r = __node_insert_multi(__p, __h.get());
2235    __h.release();
2236    return __r;
2237}
2238
2239#endif  // _LIBCPP_CXX03_LANG
2240
2241#if _LIBCPP_STD_VER > 14
2242template <class _Tp, class _Hash, class _Equal, class _Alloc>
2243template <class _NodeHandle, class _InsertReturnType>
2244_LIBCPP_INLINE_VISIBILITY
2245_InsertReturnType
2246__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_unique(
2247    _NodeHandle&& __nh)
2248{
2249    if (__nh.empty())
2250        return _InsertReturnType{end(), false, _NodeHandle()};
2251    pair<iterator, bool> __result = __node_insert_unique(__nh.__ptr_);
2252    if (__result.second)
2253        __nh.__release_ptr();
2254    return _InsertReturnType{__result.first, __result.second, _VSTD::move(__nh)};
2255}
2256
2257template <class _Tp, class _Hash, class _Equal, class _Alloc>
2258template <class _NodeHandle>
2259_LIBCPP_INLINE_VISIBILITY
2260typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2261__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_unique(
2262    const_iterator, _NodeHandle&& __nh)
2263{
2264    if (__nh.empty())
2265        return end();
2266    pair<iterator, bool> __result = __node_insert_unique(__nh.__ptr_);
2267    if (__result.second)
2268        __nh.__release_ptr();
2269    return __result.first;
2270}
2271
2272template <class _Tp, class _Hash, class _Equal, class _Alloc>
2273template <class _NodeHandle>
2274_LIBCPP_INLINE_VISIBILITY
2275_NodeHandle
2276__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_extract(
2277    key_type const& __key)
2278{
2279    iterator __i = find(__key);
2280    if (__i == end())
2281        return _NodeHandle();
2282    return __node_handle_extract<_NodeHandle>(__i);
2283}
2284
2285template <class _Tp, class _Hash, class _Equal, class _Alloc>
2286template <class _NodeHandle>
2287_LIBCPP_INLINE_VISIBILITY
2288_NodeHandle
2289__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_extract(
2290    const_iterator __p)
2291{
2292    allocator_type __alloc(__node_alloc());
2293    return _NodeHandle(remove(__p).release(), __alloc);
2294}
2295
2296template <class _Tp, class _Hash, class _Equal, class _Alloc>
2297template <class _Table>
2298_LIBCPP_INLINE_VISIBILITY
2299void
2300__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_merge_unique(
2301    _Table& __source)
2302{
2303    static_assert(is_same<__node, typename _Table::__node>::value, "");
2304
2305    for (typename _Table::iterator __it = __source.begin();
2306         __it != __source.end();)
2307    {
2308        __node_pointer __src_ptr = __it.__node_->__upcast();
2309        size_t __hash = hash_function()(__src_ptr->__value_);
2310        __next_pointer __existing_node =
2311            __node_insert_unique_prepare(__hash, __src_ptr->__value_);
2312        auto __prev_iter = __it++;
2313        if (__existing_node == nullptr)
2314        {
2315            (void)__source.remove(__prev_iter).release();
2316            __src_ptr->__hash_ = __hash;
2317            __node_insert_unique_perform(__src_ptr);
2318        }
2319    }
2320}
2321
2322template <class _Tp, class _Hash, class _Equal, class _Alloc>
2323template <class _NodeHandle>
2324_LIBCPP_INLINE_VISIBILITY
2325typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2326__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_multi(
2327    _NodeHandle&& __nh)
2328{
2329    if (__nh.empty())
2330        return end();
2331    iterator __result = __node_insert_multi(__nh.__ptr_);
2332    __nh.__release_ptr();
2333    return __result;
2334}
2335
2336template <class _Tp, class _Hash, class _Equal, class _Alloc>
2337template <class _NodeHandle>
2338_LIBCPP_INLINE_VISIBILITY
2339typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2340__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_multi(
2341    const_iterator __hint, _NodeHandle&& __nh)
2342{
2343    if (__nh.empty())
2344        return end();
2345    iterator __result = __node_insert_multi(__hint, __nh.__ptr_);
2346    __nh.__release_ptr();
2347    return __result;
2348}
2349
2350template <class _Tp, class _Hash, class _Equal, class _Alloc>
2351template <class _Table>
2352_LIBCPP_INLINE_VISIBILITY
2353void
2354__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_merge_multi(
2355    _Table& __source)
2356{
2357    static_assert(is_same<typename _Table::__node, __node>::value, "");
2358
2359    for (typename _Table::iterator __it = __source.begin();
2360         __it != __source.end();)
2361    {
2362        __node_pointer __src_ptr = __it.__node_->__upcast();
2363        size_t __src_hash = hash_function()(__src_ptr->__value_);
2364        __next_pointer __pn =
2365            __node_insert_multi_prepare(__src_hash, __src_ptr->__value_);
2366        (void)__source.remove(__it++).release();
2367        __src_ptr->__hash_ = __src_hash;
2368        __node_insert_multi_perform(__src_ptr, __pn);
2369    }
2370}
2371#endif  // _LIBCPP_STD_VER > 14
2372
2373template <class _Tp, class _Hash, class _Equal, class _Alloc>
2374void
2375__hash_table<_Tp, _Hash, _Equal, _Alloc>::rehash(size_type __n)
2376_LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
2377{
2378    if (__n == 1)
2379        __n = 2;
2380    else if (__n & (__n - 1))
2381        __n = __next_prime(__n);
2382    size_type __bc = bucket_count();
2383    if (__n > __bc)
2384        __rehash(__n);
2385    else if (__n < __bc)
2386    {
2387        __n = _VSTD::max<size_type>
2388              (
2389                  __n,
2390                  __is_hash_power2(__bc) ? __next_hash_pow2(size_t(ceil(float(size()) / max_load_factor()))) :
2391                                           __next_prime(size_t(ceil(float(size()) / max_load_factor())))
2392              );
2393        if (__n < __bc)
2394            __rehash(__n);
2395    }
2396}
2397
2398template <class _Tp, class _Hash, class _Equal, class _Alloc>
2399void
2400__hash_table<_Tp, _Hash, _Equal, _Alloc>::__rehash(size_type __nbc)
2401{
2402#if _LIBCPP_DEBUG_LEVEL >= 2
2403    __get_db()->__invalidate_all(this);
2404#endif  // _LIBCPP_DEBUG_LEVEL >= 2
2405    __pointer_allocator& __npa = __bucket_list_.get_deleter().__alloc();
2406    __bucket_list_.reset(__nbc > 0 ?
2407                      __pointer_alloc_traits::allocate(__npa, __nbc) : nullptr);
2408    __bucket_list_.get_deleter().size() = __nbc;
2409    if (__nbc > 0)
2410    {
2411        for (size_type __i = 0; __i < __nbc; ++__i)
2412            __bucket_list_[__i] = nullptr;
2413        __next_pointer __pp = __p1_.first().__ptr();
2414        __next_pointer __cp = __pp->__next_;
2415        if (__cp != nullptr)
2416        {
2417            size_type __chash = __constrain_hash(__cp->__hash(), __nbc);
2418            __bucket_list_[__chash] = __pp;
2419            size_type __phash = __chash;
2420            for (__pp = __cp, __cp = __cp->__next_; __cp != nullptr;
2421                                                           __cp = __pp->__next_)
2422            {
2423                __chash = __constrain_hash(__cp->__hash(), __nbc);
2424                if (__chash == __phash)
2425                    __pp = __cp;
2426                else
2427                {
2428                    if (__bucket_list_[__chash] == nullptr)
2429                    {
2430                        __bucket_list_[__chash] = __pp;
2431                        __pp = __cp;
2432                        __phash = __chash;
2433                    }
2434                    else
2435                    {
2436                        __next_pointer __np = __cp;
2437                        for (; __np->__next_ != nullptr &&
2438                               key_eq()(__cp->__upcast()->__value_,
2439                                        __np->__next_->__upcast()->__value_);
2440                                                           __np = __np->__next_)
2441                            ;
2442                        __pp->__next_ = __np->__next_;
2443                        __np->__next_ = __bucket_list_[__chash]->__next_;
2444                        __bucket_list_[__chash]->__next_ = __cp;
2445
2446                    }
2447                }
2448            }
2449        }
2450    }
2451}
2452
2453template <class _Tp, class _Hash, class _Equal, class _Alloc>
2454template <class _Key>
2455typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2456__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k)
2457{
2458    size_t __hash = hash_function()(__k);
2459    size_type __bc = bucket_count();
2460    if (__bc != 0)
2461    {
2462        size_t __chash = __constrain_hash(__hash, __bc);
2463        __next_pointer __nd = __bucket_list_[__chash];
2464        if (__nd != nullptr)
2465        {
2466            for (__nd = __nd->__next_; __nd != nullptr &&
2467                (__nd->__hash() == __hash
2468                  || __constrain_hash(__nd->__hash(), __bc) == __chash);
2469                                                           __nd = __nd->__next_)
2470            {
2471                if ((__nd->__hash() == __hash)
2472                    && key_eq()(__nd->__upcast()->__value_, __k))
2473#if _LIBCPP_DEBUG_LEVEL >= 2
2474                    return iterator(__nd, this);
2475#else
2476                    return iterator(__nd);
2477#endif
2478            }
2479        }
2480    }
2481    return end();
2482}
2483
2484template <class _Tp, class _Hash, class _Equal, class _Alloc>
2485template <class _Key>
2486typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
2487__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k) const
2488{
2489    size_t __hash = hash_function()(__k);
2490    size_type __bc = bucket_count();
2491    if (__bc != 0)
2492    {
2493        size_t __chash = __constrain_hash(__hash, __bc);
2494        __next_pointer __nd = __bucket_list_[__chash];
2495        if (__nd != nullptr)
2496        {
2497            for (__nd = __nd->__next_; __nd != nullptr &&
2498                (__hash == __nd->__hash()
2499                    || __constrain_hash(__nd->__hash(), __bc) == __chash);
2500                                                           __nd = __nd->__next_)
2501            {
2502                if ((__nd->__hash() == __hash)
2503                    && key_eq()(__nd->__upcast()->__value_, __k))
2504#if _LIBCPP_DEBUG_LEVEL >= 2
2505                    return const_iterator(__nd, this);
2506#else
2507                    return const_iterator(__nd);
2508#endif
2509            }
2510        }
2511
2512    }
2513    return end();
2514}
2515
2516#ifndef _LIBCPP_CXX03_LANG
2517
2518template <class _Tp, class _Hash, class _Equal, class _Alloc>
2519template <class ..._Args>
2520typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2521__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node(_Args&& ...__args)
2522{
2523    static_assert(!__is_hash_value_type<_Args...>::value,
2524                  "Construct cannot be called with a hash value type");
2525    __node_allocator& __na = __node_alloc();
2526    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2527    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), _VSTD::forward<_Args>(__args)...);
2528    __h.get_deleter().__value_constructed = true;
2529    __h->__hash_ = hash_function()(__h->__value_);
2530    __h->__next_ = nullptr;
2531    return __h;
2532}
2533
2534template <class _Tp, class _Hash, class _Equal, class _Alloc>
2535template <class _First, class ..._Rest>
2536typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2537__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(
2538    size_t __hash, _First&& __f, _Rest&& ...__rest)
2539{
2540    static_assert(!__is_hash_value_type<_First, _Rest...>::value,
2541                  "Construct cannot be called with a hash value type");
2542    __node_allocator& __na = __node_alloc();
2543    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2544    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_),
2545                             _VSTD::forward<_First>(__f),
2546                             _VSTD::forward<_Rest>(__rest)...);
2547    __h.get_deleter().__value_constructed = true;
2548    __h->__hash_ = __hash;
2549    __h->__next_ = nullptr;
2550    return __h;
2551}
2552
2553#else  // _LIBCPP_CXX03_LANG
2554
2555template <class _Tp, class _Hash, class _Equal, class _Alloc>
2556typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2557__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node(const __container_value_type& __v)
2558{
2559    __node_allocator& __na = __node_alloc();
2560    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2561    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), __v);
2562    __h.get_deleter().__value_constructed = true;
2563    __h->__hash_ = hash_function()(__h->__value_);
2564    __h->__next_ = nullptr;
2565    return _LIBCPP_EXPLICIT_MOVE(__h);  // explicitly moved for C++03
2566}
2567
2568template <class _Tp, class _Hash, class _Equal, class _Alloc>
2569typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2570__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(size_t __hash,
2571                                                                const __container_value_type& __v)
2572{
2573    __node_allocator& __na = __node_alloc();
2574    __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
2575    __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_), __v);
2576    __h.get_deleter().__value_constructed = true;
2577    __h->__hash_ = __hash;
2578    __h->__next_ = nullptr;
2579    return _LIBCPP_EXPLICIT_MOVE(__h);  // explicitly moved for C++03
2580}
2581
2582#endif  // _LIBCPP_CXX03_LANG
2583
2584template <class _Tp, class _Hash, class _Equal, class _Alloc>
2585typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2586__hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __p)
2587{
2588    __next_pointer __np = __p.__node_;
2589#if _LIBCPP_DEBUG_LEVEL >= 2
2590    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__p) == this,
2591        "unordered container erase(iterator) called with an iterator not"
2592        " referring to this container");
2593    _LIBCPP_ASSERT(__p != end(),
2594        "unordered container erase(iterator) called with a non-dereferenceable iterator");
2595    iterator __r(__np, this);
2596#else
2597    iterator __r(__np);
2598#endif
2599    ++__r;
2600    remove(__p);
2601    return __r;
2602}
2603
2604template <class _Tp, class _Hash, class _Equal, class _Alloc>
2605typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
2606__hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __first,
2607                                                const_iterator __last)
2608{
2609#if _LIBCPP_DEBUG_LEVEL >= 2
2610    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__first) == this,
2611        "unodered container::erase(iterator, iterator) called with an iterator not"
2612        " referring to this unodered container");
2613    _LIBCPP_ASSERT(__get_const_db()->__find_c_from_i(&__last) == this,
2614        "unodered container::erase(iterator, iterator) called with an iterator not"
2615        " referring to this unodered container");
2616#endif
2617    for (const_iterator __p = __first; __first != __last; __p = __first)
2618    {
2619        ++__first;
2620        erase(__p);
2621    }
2622    __next_pointer __np = __last.__node_;
2623#if _LIBCPP_DEBUG_LEVEL >= 2
2624    return iterator (__np, this);
2625#else
2626    return iterator (__np);
2627#endif
2628}
2629
2630template <class _Tp, class _Hash, class _Equal, class _Alloc>
2631template <class _Key>
2632typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2633__hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_unique(const _Key& __k)
2634{
2635    iterator __i = find(__k);
2636    if (__i == end())
2637        return 0;
2638    erase(__i);
2639    return 1;
2640}
2641
2642template <class _Tp, class _Hash, class _Equal, class _Alloc>
2643template <class _Key>
2644typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2645__hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_multi(const _Key& __k)
2646{
2647    size_type __r = 0;
2648    iterator __i = find(__k);
2649    if (__i != end())
2650    {
2651        iterator __e = end();
2652        do
2653        {
2654            erase(__i++);
2655            ++__r;
2656        } while (__i != __e && key_eq()(*__i, __k));
2657    }
2658    return __r;
2659}
2660
2661template <class _Tp, class _Hash, class _Equal, class _Alloc>
2662typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
2663__hash_table<_Tp, _Hash, _Equal, _Alloc>::remove(const_iterator __p) _NOEXCEPT
2664{
2665    // current node
2666    __next_pointer __cn = __p.__node_;
2667    size_type __bc = bucket_count();
2668    size_t __chash = __constrain_hash(__cn->__hash(), __bc);
2669    // find previous node
2670    __next_pointer __pn = __bucket_list_[__chash];
2671    for (; __pn->__next_ != __cn; __pn = __pn->__next_)
2672        ;
2673    // Fix up __bucket_list_
2674        // if __pn is not in same bucket (before begin is not in same bucket) &&
2675        //    if __cn->__next_ is not in same bucket (nullptr is not in same bucket)
2676    if (__pn == __p1_.first().__ptr()
2677            || __constrain_hash(__pn->__hash(), __bc) != __chash)
2678    {
2679        if (__cn->__next_ == nullptr
2680            || __constrain_hash(__cn->__next_->__hash(), __bc) != __chash)
2681            __bucket_list_[__chash] = nullptr;
2682    }
2683        // if __cn->__next_ is not in same bucket (nullptr is in same bucket)
2684    if (__cn->__next_ != nullptr)
2685    {
2686        size_t __nhash = __constrain_hash(__cn->__next_->__hash(), __bc);
2687        if (__nhash != __chash)
2688            __bucket_list_[__nhash] = __pn;
2689    }
2690    // remove __cn
2691    __pn->__next_ = __cn->__next_;
2692    __cn->__next_ = nullptr;
2693    --size();
2694#if _LIBCPP_DEBUG_LEVEL >= 2
2695    __c_node* __c = __get_db()->__find_c_and_lock(this);
2696    for (__i_node** __dp = __c->end_; __dp != __c->beg_; )
2697    {
2698        --__dp;
2699        iterator* __i = static_cast<iterator*>((*__dp)->__i_);
2700        if (__i->__node_ == __cn)
2701        {
2702            (*__dp)->__c_ = nullptr;
2703            if (--__c->end_ != __dp)
2704                memmove(__dp, __dp+1, (__c->end_ - __dp)*sizeof(__i_node*));
2705        }
2706    }
2707    __get_db()->unlock();
2708#endif
2709    return __node_holder(__cn->__upcast(), _Dp(__node_alloc(), true));
2710}
2711
2712template <class _Tp, class _Hash, class _Equal, class _Alloc>
2713template <class _Key>
2714inline
2715typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2716__hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_unique(const _Key& __k) const
2717{
2718    return static_cast<size_type>(find(__k) != end());
2719}
2720
2721template <class _Tp, class _Hash, class _Equal, class _Alloc>
2722template <class _Key>
2723typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2724__hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_multi(const _Key& __k) const
2725{
2726    size_type __r = 0;
2727    const_iterator __i = find(__k);
2728    if (__i != end())
2729    {
2730        const_iterator __e = end();
2731        do
2732        {
2733            ++__i;
2734            ++__r;
2735        } while (__i != __e && key_eq()(*__i, __k));
2736    }
2737    return __r;
2738}
2739
2740template <class _Tp, class _Hash, class _Equal, class _Alloc>
2741template <class _Key>
2742pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
2743     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
2744__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(
2745        const _Key& __k)
2746{
2747    iterator __i = find(__k);
2748    iterator __j = __i;
2749    if (__i != end())
2750        ++__j;
2751    return pair<iterator, iterator>(__i, __j);
2752}
2753
2754template <class _Tp, class _Hash, class _Equal, class _Alloc>
2755template <class _Key>
2756pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
2757     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
2758__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(
2759        const _Key& __k) const
2760{
2761    const_iterator __i = find(__k);
2762    const_iterator __j = __i;
2763    if (__i != end())
2764        ++__j;
2765    return pair<const_iterator, const_iterator>(__i, __j);
2766}
2767
2768template <class _Tp, class _Hash, class _Equal, class _Alloc>
2769template <class _Key>
2770pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
2771     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
2772__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(
2773        const _Key& __k)
2774{
2775    iterator __i = find(__k);
2776    iterator __j = __i;
2777    if (__i != end())
2778    {
2779        iterator __e = end();
2780        do
2781        {
2782            ++__j;
2783        } while (__j != __e && key_eq()(*__j, __k));
2784    }
2785    return pair<iterator, iterator>(__i, __j);
2786}
2787
2788template <class _Tp, class _Hash, class _Equal, class _Alloc>
2789template <class _Key>
2790pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
2791     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
2792__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(
2793        const _Key& __k) const
2794{
2795    const_iterator __i = find(__k);
2796    const_iterator __j = __i;
2797    if (__i != end())
2798    {
2799        const_iterator __e = end();
2800        do
2801        {
2802            ++__j;
2803        } while (__j != __e && key_eq()(*__j, __k));
2804    }
2805    return pair<const_iterator, const_iterator>(__i, __j);
2806}
2807
2808template <class _Tp, class _Hash, class _Equal, class _Alloc>
2809void
2810__hash_table<_Tp, _Hash, _Equal, _Alloc>::swap(__hash_table& __u)
2811#if _LIBCPP_STD_VER <= 11
2812    _NOEXCEPT_(
2813        __is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value
2814        && (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value
2815              || __is_nothrow_swappable<__pointer_allocator>::value)
2816        && (!__node_traits::propagate_on_container_swap::value
2817              || __is_nothrow_swappable<__node_allocator>::value)
2818            )
2819#else
2820  _NOEXCEPT_(__is_nothrow_swappable<hasher>::value && __is_nothrow_swappable<key_equal>::value)
2821#endif
2822{
2823    _LIBCPP_ASSERT(__node_traits::propagate_on_container_swap::value ||
2824                   this->__node_alloc() == __u.__node_alloc(),
2825                   "list::swap: Either propagate_on_container_swap must be true"
2826                   " or the allocators must compare equal");
2827    {
2828    __node_pointer_pointer __npp = __bucket_list_.release();
2829    __bucket_list_.reset(__u.__bucket_list_.release());
2830    __u.__bucket_list_.reset(__npp);
2831    }
2832    _VSTD::swap(__bucket_list_.get_deleter().size(), __u.__bucket_list_.get_deleter().size());
2833    __swap_allocator(__bucket_list_.get_deleter().__alloc(),
2834             __u.__bucket_list_.get_deleter().__alloc());
2835    __swap_allocator(__node_alloc(), __u.__node_alloc());
2836    _VSTD::swap(__p1_.first().__next_, __u.__p1_.first().__next_);
2837    __p2_.swap(__u.__p2_);
2838    __p3_.swap(__u.__p3_);
2839    if (size() > 0)
2840        __bucket_list_[__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] =
2841            __p1_.first().__ptr();
2842    if (__u.size() > 0)
2843        __u.__bucket_list_[__constrain_hash(__u.__p1_.first().__next_->__hash(), __u.bucket_count())] =
2844            __u.__p1_.first().__ptr();
2845#if _LIBCPP_DEBUG_LEVEL >= 2
2846    __get_db()->swap(this, &__u);
2847#endif
2848}
2849
2850template <class _Tp, class _Hash, class _Equal, class _Alloc>
2851typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
2852__hash_table<_Tp, _Hash, _Equal, _Alloc>::bucket_size(size_type __n) const
2853{
2854    _LIBCPP_ASSERT(__n < bucket_count(),
2855        "unordered container::bucket_size(n) called with n >= bucket_count()");
2856    __next_pointer __np = __bucket_list_[__n];
2857    size_type __bc = bucket_count();
2858    size_type __r = 0;
2859    if (__np != nullptr)
2860    {
2861        for (__np = __np->__next_; __np != nullptr &&
2862                                   __constrain_hash(__np->__hash(), __bc) == __n;
2863                                                    __np = __np->__next_, ++__r)
2864            ;
2865    }
2866    return __r;
2867}
2868
2869template <class _Tp, class _Hash, class _Equal, class _Alloc>
2870inline _LIBCPP_INLINE_VISIBILITY
2871void
2872swap(__hash_table<_Tp, _Hash, _Equal, _Alloc>& __x,
2873     __hash_table<_Tp, _Hash, _Equal, _Alloc>& __y)
2874    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y)))
2875{
2876    __x.swap(__y);
2877}
2878
2879#if _LIBCPP_DEBUG_LEVEL >= 2
2880
2881template <class _Tp, class _Hash, class _Equal, class _Alloc>
2882bool
2883__hash_table<_Tp, _Hash, _Equal, _Alloc>::__dereferenceable(const const_iterator* __i) const
2884{
2885    return __i->__node_ != nullptr;
2886}
2887
2888template <class _Tp, class _Hash, class _Equal, class _Alloc>
2889bool
2890__hash_table<_Tp, _Hash, _Equal, _Alloc>::__decrementable(const const_iterator*) const
2891{
2892    return false;
2893}
2894
2895template <class _Tp, class _Hash, class _Equal, class _Alloc>
2896bool
2897__hash_table<_Tp, _Hash, _Equal, _Alloc>::__addable(const const_iterator*, ptrdiff_t) const
2898{
2899    return false;
2900}
2901
2902template <class _Tp, class _Hash, class _Equal, class _Alloc>
2903bool
2904__hash_table<_Tp, _Hash, _Equal, _Alloc>::__subscriptable(const const_iterator*, ptrdiff_t) const
2905{
2906    return false;
2907}
2908
2909#endif  // _LIBCPP_DEBUG_LEVEL >= 2
2910
2911_LIBCPP_END_NAMESPACE_STD
2912
2913_LIBCPP_POP_MACROS
2914
2915#endif  // _LIBCPP__HASH_TABLE
2916