xref: /freebsd/contrib/llvm-project/libcxx/include/__hash_table (revision 96190b4fef3b4a0cc3ca0606b0c4e3e69a5e6717)
1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP___HASH_TABLE
11#define _LIBCPP___HASH_TABLE
12
13#include <__algorithm/max.h>
14#include <__algorithm/min.h>
15#include <__assert>
16#include <__bit/countl.h>
17#include <__config>
18#include <__functional/hash.h>
19#include <__functional/invoke.h>
20#include <__iterator/iterator_traits.h>
21#include <__memory/addressof.h>
22#include <__memory/allocator_traits.h>
23#include <__memory/compressed_pair.h>
24#include <__memory/construct_at.h>
25#include <__memory/pointer_traits.h>
26#include <__memory/swap_allocator.h>
27#include <__memory/unique_ptr.h>
28#include <__type_traits/can_extract_key.h>
29#include <__type_traits/conditional.h>
30#include <__type_traits/is_const.h>
31#include <__type_traits/is_copy_constructible.h>
32#include <__type_traits/is_nothrow_constructible.h>
33#include <__type_traits/is_nothrow_copy_constructible.h>
34#include <__type_traits/is_nothrow_default_constructible.h>
35#include <__type_traits/is_nothrow_move_assignable.h>
36#include <__type_traits/is_nothrow_move_constructible.h>
37#include <__type_traits/is_pointer.h>
38#include <__type_traits/is_reference.h>
39#include <__type_traits/is_swappable.h>
40#include <__type_traits/remove_const.h>
41#include <__type_traits/remove_cvref.h>
42#include <__utility/forward.h>
43#include <__utility/move.h>
44#include <__utility/pair.h>
45#include <__utility/swap.h>
46#include <cmath>
47#include <cstring>
48#include <initializer_list>
49#include <new> // __launder
50
51#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
52#  pragma GCC system_header
53#endif
54
55_LIBCPP_PUSH_MACROS
56#include <__undef_macros>
57
58_LIBCPP_BEGIN_NAMESPACE_STD
59
60template <class _Key, class _Tp>
61struct __hash_value_type;
62
63template <class _Tp>
64struct __is_hash_value_type_imp : false_type {};
65
66template <class _Key, class _Value>
67struct __is_hash_value_type_imp<__hash_value_type<_Key, _Value> > : true_type {};
68
69template <class... _Args>
70struct __is_hash_value_type : false_type {};
71
72template <class _One>
73struct __is_hash_value_type<_One> : __is_hash_value_type_imp<__remove_cvref_t<_One> > {};
74
75_LIBCPP_EXPORTED_FROM_ABI size_t __next_prime(size_t __n);
76
77template <class _NodePtr>
78struct __hash_node_base {
79  typedef typename pointer_traits<_NodePtr>::element_type __node_type;
80  typedef __hash_node_base __first_node;
81  typedef __rebind_pointer_t<_NodePtr, __first_node> __node_base_pointer;
82  typedef _NodePtr __node_pointer;
83
84#if defined(_LIBCPP_ABI_FIX_UNORDERED_NODE_POINTER_UB)
85  typedef __node_base_pointer __next_pointer;
86#else
87  typedef __conditional_t<is_pointer<__node_pointer>::value, __node_base_pointer, __node_pointer> __next_pointer;
88#endif
89
90  __next_pointer __next_;
91
92  _LIBCPP_HIDE_FROM_ABI __next_pointer __ptr() _NOEXCEPT {
93    return static_cast<__next_pointer>(pointer_traits<__node_base_pointer>::pointer_to(*this));
94  }
95
96  _LIBCPP_HIDE_FROM_ABI __node_pointer __upcast() _NOEXCEPT {
97    return static_cast<__node_pointer>(pointer_traits<__node_base_pointer>::pointer_to(*this));
98  }
99
100  _LIBCPP_HIDE_FROM_ABI size_t __hash() const _NOEXCEPT { return static_cast<__node_type const&>(*this).__hash_; }
101
102  _LIBCPP_HIDE_FROM_ABI __hash_node_base() _NOEXCEPT : __next_(nullptr) {}
103  _LIBCPP_HIDE_FROM_ABI explicit __hash_node_base(__next_pointer __next) _NOEXCEPT : __next_(__next) {}
104};
105
106template <class _Tp, class _VoidPtr>
107struct __hash_node : public __hash_node_base< __rebind_pointer_t<_VoidPtr, __hash_node<_Tp, _VoidPtr> > > {
108  typedef _Tp __node_value_type;
109  using _Base          = __hash_node_base<__rebind_pointer_t<_VoidPtr, __hash_node<_Tp, _VoidPtr> > >;
110  using __next_pointer = typename _Base::__next_pointer;
111
112  size_t __hash_;
113
114  // We allow starting the lifetime of nodes without initializing the value held by the node,
115  // since that is handled by the hash table itself in order to be allocator-aware.
116#ifndef _LIBCPP_CXX03_LANG
117
118private:
119  union {
120    _Tp __value_;
121  };
122
123public:
124  _LIBCPP_HIDE_FROM_ABI _Tp& __get_value() { return __value_; }
125#else
126
127private:
128  _ALIGNAS_TYPE(_Tp) char __buffer_[sizeof(_Tp)];
129
130public:
131  _LIBCPP_HIDE_FROM_ABI _Tp& __get_value() { return *std::__launder(reinterpret_cast<_Tp*>(&__buffer_)); }
132#endif
133
134  _LIBCPP_HIDE_FROM_ABI explicit __hash_node(__next_pointer __next, size_t __hash) : _Base(__next), __hash_(__hash) {}
135  _LIBCPP_HIDE_FROM_ABI ~__hash_node() {}
136};
137
138inline _LIBCPP_HIDE_FROM_ABI bool __is_hash_power2(size_t __bc) { return __bc > 2 && !(__bc & (__bc - 1)); }
139
140inline _LIBCPP_HIDE_FROM_ABI size_t __constrain_hash(size_t __h, size_t __bc) {
141  return !(__bc & (__bc - 1)) ? __h & (__bc - 1) : (__h < __bc ? __h : __h % __bc);
142}
143
144inline _LIBCPP_HIDE_FROM_ABI size_t __next_hash_pow2(size_t __n) {
145  return __n < 2 ? __n : (size_t(1) << (numeric_limits<size_t>::digits - __libcpp_clz(__n - 1)));
146}
147
148template <class _Tp, class _Hash, class _Equal, class _Alloc>
149class __hash_table;
150
151template <class _NodePtr>
152class _LIBCPP_TEMPLATE_VIS __hash_iterator;
153template <class _ConstNodePtr>
154class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
155template <class _NodePtr>
156class _LIBCPP_TEMPLATE_VIS __hash_local_iterator;
157template <class _ConstNodePtr>
158class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
159template <class _HashIterator>
160class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
161template <class _HashIterator>
162class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
163
164template <class _Tp>
165struct __hash_key_value_types {
166  static_assert(!is_reference<_Tp>::value && !is_const<_Tp>::value, "");
167  typedef _Tp key_type;
168  typedef _Tp __node_value_type;
169  typedef _Tp __container_value_type;
170  static const bool __is_map = false;
171
172  _LIBCPP_HIDE_FROM_ABI static key_type const& __get_key(_Tp const& __v) { return __v; }
173  _LIBCPP_HIDE_FROM_ABI static __container_value_type const& __get_value(__node_value_type const& __v) { return __v; }
174  _LIBCPP_HIDE_FROM_ABI static __container_value_type* __get_ptr(__node_value_type& __n) { return std::addressof(__n); }
175  _LIBCPP_HIDE_FROM_ABI static __container_value_type&& __move(__node_value_type& __v) { return std::move(__v); }
176};
177
178template <class _Key, class _Tp>
179struct __hash_key_value_types<__hash_value_type<_Key, _Tp> > {
180  typedef _Key key_type;
181  typedef _Tp mapped_type;
182  typedef __hash_value_type<_Key, _Tp> __node_value_type;
183  typedef pair<const _Key, _Tp> __container_value_type;
184  typedef __container_value_type __map_value_type;
185  static const bool __is_map = true;
186
187  _LIBCPP_HIDE_FROM_ABI static key_type const& __get_key(__container_value_type const& __v) { return __v.first; }
188
189  template <class _Up, __enable_if_t<__is_same_uncvref<_Up, __node_value_type>::value, int> = 0>
190  _LIBCPP_HIDE_FROM_ABI static __container_value_type const& __get_value(_Up& __t) {
191    return __t.__get_value();
192  }
193
194  template <class _Up, __enable_if_t<__is_same_uncvref<_Up, __container_value_type>::value, int> = 0>
195  _LIBCPP_HIDE_FROM_ABI static __container_value_type const& __get_value(_Up& __t) {
196    return __t;
197  }
198
199  _LIBCPP_HIDE_FROM_ABI static __container_value_type* __get_ptr(__node_value_type& __n) {
200    return std::addressof(__n.__get_value());
201  }
202  _LIBCPP_HIDE_FROM_ABI static pair<key_type&&, mapped_type&&> __move(__node_value_type& __v) { return __v.__move(); }
203};
204
205template <class _Tp, class _AllocPtr, class _KVTypes = __hash_key_value_types<_Tp>, bool = _KVTypes::__is_map>
206struct __hash_map_pointer_types {};
207
208template <class _Tp, class _AllocPtr, class _KVTypes>
209struct __hash_map_pointer_types<_Tp, _AllocPtr, _KVTypes, true> {
210  typedef typename _KVTypes::__map_value_type _Mv;
211  typedef __rebind_pointer_t<_AllocPtr, _Mv> __map_value_type_pointer;
212  typedef __rebind_pointer_t<_AllocPtr, const _Mv> __const_map_value_type_pointer;
213};
214
215template <class _NodePtr, class _NodeT = typename pointer_traits<_NodePtr>::element_type>
216struct __hash_node_types;
217
218template <class _NodePtr, class _Tp, class _VoidPtr>
219struct __hash_node_types<_NodePtr, __hash_node<_Tp, _VoidPtr> >
220    : public __hash_key_value_types<_Tp>,
221      __hash_map_pointer_types<_Tp, _VoidPtr>
222
223{
224  typedef __hash_key_value_types<_Tp> __base;
225
226public:
227  typedef ptrdiff_t difference_type;
228  typedef size_t size_type;
229
230  typedef __rebind_pointer_t<_NodePtr, void> __void_pointer;
231
232  typedef typename pointer_traits<_NodePtr>::element_type __node_type;
233  typedef _NodePtr __node_pointer;
234
235  typedef __hash_node_base<__node_pointer> __node_base_type;
236  typedef __rebind_pointer_t<_NodePtr, __node_base_type> __node_base_pointer;
237
238  typedef typename __node_base_type::__next_pointer __next_pointer;
239
240  typedef _Tp __node_value_type;
241  typedef __rebind_pointer_t<_VoidPtr, __node_value_type> __node_value_type_pointer;
242  typedef __rebind_pointer_t<_VoidPtr, const __node_value_type> __const_node_value_type_pointer;
243
244private:
245  static_assert(!is_const<__node_type>::value, "_NodePtr should never be a pointer to const");
246  static_assert((is_same<typename pointer_traits<_VoidPtr>::element_type, void>::value),
247                "_VoidPtr does not point to unqualified void type");
248  static_assert((is_same<__rebind_pointer_t<_VoidPtr, __node_type>, _NodePtr>::value),
249                "_VoidPtr does not rebind to _NodePtr.");
250};
251
252template <class _HashIterator>
253struct __hash_node_types_from_iterator;
254template <class _NodePtr>
255struct __hash_node_types_from_iterator<__hash_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
256template <class _NodePtr>
257struct __hash_node_types_from_iterator<__hash_const_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
258template <class _NodePtr>
259struct __hash_node_types_from_iterator<__hash_local_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
260template <class _NodePtr>
261struct __hash_node_types_from_iterator<__hash_const_local_iterator<_NodePtr> > : __hash_node_types<_NodePtr> {};
262
263template <class _NodeValueTp, class _VoidPtr>
264struct __make_hash_node_types {
265  typedef __hash_node<_NodeValueTp, _VoidPtr> _NodeTp;
266  typedef __rebind_pointer_t<_VoidPtr, _NodeTp> _NodePtr;
267  typedef __hash_node_types<_NodePtr> type;
268};
269
270template <class _NodePtr>
271class _LIBCPP_TEMPLATE_VIS __hash_iterator {
272  typedef __hash_node_types<_NodePtr> _NodeTypes;
273  typedef _NodePtr __node_pointer;
274  typedef typename _NodeTypes::__next_pointer __next_pointer;
275
276  __next_pointer __node_;
277
278public:
279  typedef forward_iterator_tag iterator_category;
280  typedef typename _NodeTypes::__node_value_type value_type;
281  typedef typename _NodeTypes::difference_type difference_type;
282  typedef value_type& reference;
283  typedef typename _NodeTypes::__node_value_type_pointer pointer;
284
285  _LIBCPP_HIDE_FROM_ABI __hash_iterator() _NOEXCEPT : __node_(nullptr) {}
286
287  _LIBCPP_HIDE_FROM_ABI reference operator*() const { return __node_->__upcast()->__get_value(); }
288
289  _LIBCPP_HIDE_FROM_ABI pointer operator->() const {
290    return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__get_value());
291  }
292
293  _LIBCPP_HIDE_FROM_ABI __hash_iterator& operator++() {
294    __node_ = __node_->__next_;
295    return *this;
296  }
297
298  _LIBCPP_HIDE_FROM_ABI __hash_iterator operator++(int) {
299    __hash_iterator __t(*this);
300    ++(*this);
301    return __t;
302  }
303
304  friend _LIBCPP_HIDE_FROM_ABI bool operator==(const __hash_iterator& __x, const __hash_iterator& __y) {
305    return __x.__node_ == __y.__node_;
306  }
307  friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const __hash_iterator& __x, const __hash_iterator& __y) {
308    return !(__x == __y);
309  }
310
311private:
312  _LIBCPP_HIDE_FROM_ABI explicit __hash_iterator(__next_pointer __node) _NOEXCEPT : __node_(__node) {}
313
314  template <class, class, class, class>
315  friend class __hash_table;
316  template <class>
317  friend class _LIBCPP_TEMPLATE_VIS __hash_const_iterator;
318  template <class>
319  friend class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
320  template <class, class, class, class, class>
321  friend class _LIBCPP_TEMPLATE_VIS unordered_map;
322  template <class, class, class, class, class>
323  friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
324};
325
326template <class _NodePtr>
327class _LIBCPP_TEMPLATE_VIS __hash_const_iterator {
328  static_assert(!is_const<typename pointer_traits<_NodePtr>::element_type>::value, "");
329  typedef __hash_node_types<_NodePtr> _NodeTypes;
330  typedef _NodePtr __node_pointer;
331  typedef typename _NodeTypes::__next_pointer __next_pointer;
332
333  __next_pointer __node_;
334
335public:
336  typedef __hash_iterator<_NodePtr> __non_const_iterator;
337
338  typedef forward_iterator_tag iterator_category;
339  typedef typename _NodeTypes::__node_value_type value_type;
340  typedef typename _NodeTypes::difference_type difference_type;
341  typedef const value_type& reference;
342  typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
343
344  _LIBCPP_HIDE_FROM_ABI __hash_const_iterator() _NOEXCEPT : __node_(nullptr) {}
345
346  _LIBCPP_HIDE_FROM_ABI __hash_const_iterator(const __non_const_iterator& __x) _NOEXCEPT : __node_(__x.__node_) {}
347
348  _LIBCPP_HIDE_FROM_ABI reference operator*() const { return __node_->__upcast()->__get_value(); }
349  _LIBCPP_HIDE_FROM_ABI pointer operator->() const {
350    return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__get_value());
351  }
352
353  _LIBCPP_HIDE_FROM_ABI __hash_const_iterator& operator++() {
354    __node_ = __node_->__next_;
355    return *this;
356  }
357
358  _LIBCPP_HIDE_FROM_ABI __hash_const_iterator operator++(int) {
359    __hash_const_iterator __t(*this);
360    ++(*this);
361    return __t;
362  }
363
364  friend _LIBCPP_HIDE_FROM_ABI bool operator==(const __hash_const_iterator& __x, const __hash_const_iterator& __y) {
365    return __x.__node_ == __y.__node_;
366  }
367  friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const __hash_const_iterator& __x, const __hash_const_iterator& __y) {
368    return !(__x == __y);
369  }
370
371private:
372  _LIBCPP_HIDE_FROM_ABI explicit __hash_const_iterator(__next_pointer __node) _NOEXCEPT : __node_(__node) {}
373
374  template <class, class, class, class>
375  friend class __hash_table;
376  template <class>
377  friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
378  template <class, class, class, class, class>
379  friend class _LIBCPP_TEMPLATE_VIS unordered_map;
380  template <class, class, class, class, class>
381  friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
382};
383
384template <class _NodePtr>
385class _LIBCPP_TEMPLATE_VIS __hash_local_iterator {
386  typedef __hash_node_types<_NodePtr> _NodeTypes;
387  typedef _NodePtr __node_pointer;
388  typedef typename _NodeTypes::__next_pointer __next_pointer;
389
390  __next_pointer __node_;
391  size_t __bucket_;
392  size_t __bucket_count_;
393
394public:
395  typedef forward_iterator_tag iterator_category;
396  typedef typename _NodeTypes::__node_value_type value_type;
397  typedef typename _NodeTypes::difference_type difference_type;
398  typedef value_type& reference;
399  typedef typename _NodeTypes::__node_value_type_pointer pointer;
400
401  _LIBCPP_HIDE_FROM_ABI __hash_local_iterator() _NOEXCEPT : __node_(nullptr) {}
402
403  _LIBCPP_HIDE_FROM_ABI reference operator*() const { return __node_->__upcast()->__get_value(); }
404
405  _LIBCPP_HIDE_FROM_ABI pointer operator->() const {
406    return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__get_value());
407  }
408
409  _LIBCPP_HIDE_FROM_ABI __hash_local_iterator& operator++() {
410    __node_ = __node_->__next_;
411    if (__node_ != nullptr && std::__constrain_hash(__node_->__hash(), __bucket_count_) != __bucket_)
412      __node_ = nullptr;
413    return *this;
414  }
415
416  _LIBCPP_HIDE_FROM_ABI __hash_local_iterator operator++(int) {
417    __hash_local_iterator __t(*this);
418    ++(*this);
419    return __t;
420  }
421
422  friend _LIBCPP_HIDE_FROM_ABI bool operator==(const __hash_local_iterator& __x, const __hash_local_iterator& __y) {
423    return __x.__node_ == __y.__node_;
424  }
425  friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const __hash_local_iterator& __x, const __hash_local_iterator& __y) {
426    return !(__x == __y);
427  }
428
429private:
430  _LIBCPP_HIDE_FROM_ABI explicit __hash_local_iterator(
431      __next_pointer __node, size_t __bucket, size_t __bucket_count) _NOEXCEPT
432      : __node_(__node),
433        __bucket_(__bucket),
434        __bucket_count_(__bucket_count) {
435    if (__node_ != nullptr)
436      __node_ = __node_->__next_;
437  }
438
439  template <class, class, class, class>
440  friend class __hash_table;
441  template <class>
442  friend class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator;
443  template <class>
444  friend class _LIBCPP_TEMPLATE_VIS __hash_map_iterator;
445};
446
447template <class _ConstNodePtr>
448class _LIBCPP_TEMPLATE_VIS __hash_const_local_iterator {
449  typedef __hash_node_types<_ConstNodePtr> _NodeTypes;
450  typedef _ConstNodePtr __node_pointer;
451  typedef typename _NodeTypes::__next_pointer __next_pointer;
452
453  __next_pointer __node_;
454  size_t __bucket_;
455  size_t __bucket_count_;
456
457  typedef pointer_traits<__node_pointer> __pointer_traits;
458  typedef typename __pointer_traits::element_type __node;
459  typedef __remove_const_t<__node> __non_const_node;
460  typedef __rebind_pointer_t<__node_pointer, __non_const_node> __non_const_node_pointer;
461
462public:
463  typedef __hash_local_iterator<__non_const_node_pointer> __non_const_iterator;
464
465  typedef forward_iterator_tag iterator_category;
466  typedef typename _NodeTypes::__node_value_type value_type;
467  typedef typename _NodeTypes::difference_type difference_type;
468  typedef const value_type& reference;
469  typedef typename _NodeTypes::__const_node_value_type_pointer pointer;
470
471  _LIBCPP_HIDE_FROM_ABI __hash_const_local_iterator() _NOEXCEPT : __node_(nullptr) {}
472
473  _LIBCPP_HIDE_FROM_ABI __hash_const_local_iterator(const __non_const_iterator& __x) _NOEXCEPT
474      : __node_(__x.__node_),
475        __bucket_(__x.__bucket_),
476        __bucket_count_(__x.__bucket_count_) {}
477
478  _LIBCPP_HIDE_FROM_ABI reference operator*() const { return __node_->__upcast()->__get_value(); }
479
480  _LIBCPP_HIDE_FROM_ABI pointer operator->() const {
481    return pointer_traits<pointer>::pointer_to(__node_->__upcast()->__get_value());
482  }
483
484  _LIBCPP_HIDE_FROM_ABI __hash_const_local_iterator& operator++() {
485    __node_ = __node_->__next_;
486    if (__node_ != nullptr && std::__constrain_hash(__node_->__hash(), __bucket_count_) != __bucket_)
487      __node_ = nullptr;
488    return *this;
489  }
490
491  _LIBCPP_HIDE_FROM_ABI __hash_const_local_iterator operator++(int) {
492    __hash_const_local_iterator __t(*this);
493    ++(*this);
494    return __t;
495  }
496
497  friend _LIBCPP_HIDE_FROM_ABI bool
498  operator==(const __hash_const_local_iterator& __x, const __hash_const_local_iterator& __y) {
499    return __x.__node_ == __y.__node_;
500  }
501  friend _LIBCPP_HIDE_FROM_ABI bool
502  operator!=(const __hash_const_local_iterator& __x, const __hash_const_local_iterator& __y) {
503    return !(__x == __y);
504  }
505
506private:
507  _LIBCPP_HIDE_FROM_ABI explicit __hash_const_local_iterator(
508      __next_pointer __node_ptr, size_t __bucket, size_t __bucket_count) _NOEXCEPT
509      : __node_(__node_ptr),
510        __bucket_(__bucket),
511        __bucket_count_(__bucket_count) {
512    if (__node_ != nullptr)
513      __node_ = __node_->__next_;
514  }
515
516  template <class, class, class, class>
517  friend class __hash_table;
518  template <class>
519  friend class _LIBCPP_TEMPLATE_VIS __hash_map_const_iterator;
520};
521
522template <class _Alloc>
523class __bucket_list_deallocator {
524  typedef _Alloc allocator_type;
525  typedef allocator_traits<allocator_type> __alloc_traits;
526  typedef typename __alloc_traits::size_type size_type;
527
528  __compressed_pair<size_type, allocator_type> __data_;
529
530public:
531  typedef typename __alloc_traits::pointer pointer;
532
533  _LIBCPP_HIDE_FROM_ABI __bucket_list_deallocator() _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
534      : __data_(0, __default_init_tag()) {}
535
536  _LIBCPP_HIDE_FROM_ABI __bucket_list_deallocator(const allocator_type& __a, size_type __size)
537      _NOEXCEPT_(is_nothrow_copy_constructible<allocator_type>::value)
538      : __data_(__size, __a) {}
539
540  _LIBCPP_HIDE_FROM_ABI __bucket_list_deallocator(__bucket_list_deallocator&& __x)
541      _NOEXCEPT_(is_nothrow_move_constructible<allocator_type>::value)
542      : __data_(std::move(__x.__data_)) {
543    __x.size() = 0;
544  }
545
546  _LIBCPP_HIDE_FROM_ABI size_type& size() _NOEXCEPT { return __data_.first(); }
547  _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __data_.first(); }
548
549  _LIBCPP_HIDE_FROM_ABI allocator_type& __alloc() _NOEXCEPT { return __data_.second(); }
550  _LIBCPP_HIDE_FROM_ABI const allocator_type& __alloc() const _NOEXCEPT { return __data_.second(); }
551
552  _LIBCPP_HIDE_FROM_ABI void operator()(pointer __p) _NOEXCEPT { __alloc_traits::deallocate(__alloc(), __p, size()); }
553};
554
555template <class _Alloc>
556class __hash_map_node_destructor;
557
558template <class _Alloc>
559class __hash_node_destructor {
560  typedef _Alloc allocator_type;
561  typedef allocator_traits<allocator_type> __alloc_traits;
562
563public:
564  typedef typename __alloc_traits::pointer pointer;
565
566private:
567  typedef __hash_node_types<pointer> _NodeTypes;
568
569  allocator_type& __na_;
570
571public:
572  bool __value_constructed;
573
574  _LIBCPP_HIDE_FROM_ABI __hash_node_destructor(__hash_node_destructor const&)            = default;
575  _LIBCPP_HIDE_FROM_ABI __hash_node_destructor& operator=(const __hash_node_destructor&) = delete;
576
577  _LIBCPP_HIDE_FROM_ABI explicit __hash_node_destructor(allocator_type& __na, bool __constructed = false) _NOEXCEPT
578      : __na_(__na),
579        __value_constructed(__constructed) {}
580
581  _LIBCPP_HIDE_FROM_ABI void operator()(pointer __p) _NOEXCEPT {
582    if (__value_constructed) {
583      __alloc_traits::destroy(__na_, _NodeTypes::__get_ptr(__p->__get_value()));
584      std::__destroy_at(std::addressof(*__p));
585    }
586    if (__p)
587      __alloc_traits::deallocate(__na_, __p, 1);
588  }
589
590  template <class>
591  friend class __hash_map_node_destructor;
592};
593
594#if _LIBCPP_STD_VER >= 17
595template <class _NodeType, class _Alloc>
596struct __generic_container_node_destructor;
597
598template <class _Tp, class _VoidPtr, class _Alloc>
599struct __generic_container_node_destructor<__hash_node<_Tp, _VoidPtr>, _Alloc> : __hash_node_destructor<_Alloc> {
600  using __hash_node_destructor<_Alloc>::__hash_node_destructor;
601};
602#endif
603
604template <class _Key, class _Hash, class _Equal>
605struct __enforce_unordered_container_requirements {
606#ifndef _LIBCPP_CXX03_LANG
607  static_assert(__check_hash_requirements<_Key, _Hash>::value,
608                "the specified hash does not meet the Hash requirements");
609  static_assert(is_copy_constructible<_Equal>::value, "the specified comparator is required to be copy constructible");
610#endif
611  typedef int type;
612};
613
614template <class _Key, class _Hash, class _Equal>
615#ifndef _LIBCPP_CXX03_LANG
616_LIBCPP_DIAGNOSE_WARNING(!__invokable<_Equal const&, _Key const&, _Key const&>::value,
617                         "the specified comparator type does not provide a viable const call operator")
618_LIBCPP_DIAGNOSE_WARNING(!__invokable<_Hash const&, _Key const&>::value,
619                         "the specified hash functor does not provide a viable const call operator")
620#endif
621    typename __enforce_unordered_container_requirements<_Key, _Hash, _Equal>::type
622    __diagnose_unordered_container_requirements(int);
623
624// This dummy overload is used so that the compiler won't emit a spurious
625// "no matching function for call to __diagnose_unordered_xxx" diagnostic
626// when the overload above causes a hard error.
627template <class _Key, class _Hash, class _Equal>
628int __diagnose_unordered_container_requirements(void*);
629
630template <class _Tp, class _Hash, class _Equal, class _Alloc>
631class __hash_table {
632public:
633  typedef _Tp value_type;
634  typedef _Hash hasher;
635  typedef _Equal key_equal;
636  typedef _Alloc allocator_type;
637
638private:
639  typedef allocator_traits<allocator_type> __alloc_traits;
640  typedef typename __make_hash_node_types<value_type, typename __alloc_traits::void_pointer>::type _NodeTypes;
641
642public:
643  typedef typename _NodeTypes::__node_value_type __node_value_type;
644  typedef typename _NodeTypes::__container_value_type __container_value_type;
645  typedef typename _NodeTypes::key_type key_type;
646  typedef value_type& reference;
647  typedef const value_type& const_reference;
648  typedef typename __alloc_traits::pointer pointer;
649  typedef typename __alloc_traits::const_pointer const_pointer;
650#ifndef _LIBCPP_ABI_FIX_UNORDERED_CONTAINER_SIZE_TYPE
651  typedef typename __alloc_traits::size_type size_type;
652#else
653  typedef typename _NodeTypes::size_type size_type;
654#endif
655  typedef typename _NodeTypes::difference_type difference_type;
656
657public:
658  // Create __node
659
660  typedef typename _NodeTypes::__node_type __node;
661  typedef __rebind_alloc<__alloc_traits, __node> __node_allocator;
662  typedef allocator_traits<__node_allocator> __node_traits;
663  typedef typename _NodeTypes::__void_pointer __void_pointer;
664  typedef typename _NodeTypes::__node_pointer __node_pointer;
665  typedef typename _NodeTypes::__node_pointer __node_const_pointer;
666  typedef typename _NodeTypes::__node_base_type __first_node;
667  typedef typename _NodeTypes::__node_base_pointer __node_base_pointer;
668  typedef typename _NodeTypes::__next_pointer __next_pointer;
669
670private:
671  // check for sane allocator pointer rebinding semantics. Rebinding the
672  // allocator for a new pointer type should be exactly the same as rebinding
673  // the pointer using 'pointer_traits'.
674  static_assert((is_same<__node_pointer, typename __node_traits::pointer>::value),
675                "Allocator does not rebind pointers in a sane manner.");
676  typedef __rebind_alloc<__node_traits, __first_node> __node_base_allocator;
677  typedef allocator_traits<__node_base_allocator> __node_base_traits;
678  static_assert((is_same<__node_base_pointer, typename __node_base_traits::pointer>::value),
679                "Allocator does not rebind pointers in a sane manner.");
680
681private:
682  typedef __rebind_alloc<__node_traits, __next_pointer> __pointer_allocator;
683  typedef __bucket_list_deallocator<__pointer_allocator> __bucket_list_deleter;
684  typedef unique_ptr<__next_pointer[], __bucket_list_deleter> __bucket_list;
685  typedef allocator_traits<__pointer_allocator> __pointer_alloc_traits;
686  typedef typename __bucket_list_deleter::pointer __node_pointer_pointer;
687
688  // --- Member data begin ---
689  __bucket_list __bucket_list_;
690  __compressed_pair<__first_node, __node_allocator> __p1_;
691  __compressed_pair<size_type, hasher> __p2_;
692  __compressed_pair<float, key_equal> __p3_;
693  // --- Member data end ---
694
695  _LIBCPP_HIDE_FROM_ABI size_type& size() _NOEXCEPT { return __p2_.first(); }
696
697public:
698  _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __p2_.first(); }
699
700  _LIBCPP_HIDE_FROM_ABI hasher& hash_function() _NOEXCEPT { return __p2_.second(); }
701  _LIBCPP_HIDE_FROM_ABI const hasher& hash_function() const _NOEXCEPT { return __p2_.second(); }
702
703  _LIBCPP_HIDE_FROM_ABI float& max_load_factor() _NOEXCEPT { return __p3_.first(); }
704  _LIBCPP_HIDE_FROM_ABI float max_load_factor() const _NOEXCEPT { return __p3_.first(); }
705
706  _LIBCPP_HIDE_FROM_ABI key_equal& key_eq() _NOEXCEPT { return __p3_.second(); }
707  _LIBCPP_HIDE_FROM_ABI const key_equal& key_eq() const _NOEXCEPT { return __p3_.second(); }
708
709  _LIBCPP_HIDE_FROM_ABI __node_allocator& __node_alloc() _NOEXCEPT { return __p1_.second(); }
710  _LIBCPP_HIDE_FROM_ABI const __node_allocator& __node_alloc() const _NOEXCEPT { return __p1_.second(); }
711
712public:
713  typedef __hash_iterator<__node_pointer> iterator;
714  typedef __hash_const_iterator<__node_pointer> const_iterator;
715  typedef __hash_local_iterator<__node_pointer> local_iterator;
716  typedef __hash_const_local_iterator<__node_pointer> const_local_iterator;
717
718  _LIBCPP_HIDE_FROM_ABI __hash_table() _NOEXCEPT_(
719      is_nothrow_default_constructible<__bucket_list>::value&& is_nothrow_default_constructible<__first_node>::value&&
720          is_nothrow_default_constructible<__node_allocator>::value&& is_nothrow_default_constructible<hasher>::value&&
721              is_nothrow_default_constructible<key_equal>::value);
722  _LIBCPP_HIDE_FROM_ABI __hash_table(const hasher& __hf, const key_equal& __eql);
723  _LIBCPP_HIDE_FROM_ABI __hash_table(const hasher& __hf, const key_equal& __eql, const allocator_type& __a);
724  _LIBCPP_HIDE_FROM_ABI explicit __hash_table(const allocator_type& __a);
725  _LIBCPP_HIDE_FROM_ABI __hash_table(const __hash_table& __u);
726  _LIBCPP_HIDE_FROM_ABI __hash_table(const __hash_table& __u, const allocator_type& __a);
727  _LIBCPP_HIDE_FROM_ABI __hash_table(__hash_table&& __u) _NOEXCEPT_(
728      is_nothrow_move_constructible<__bucket_list>::value&& is_nothrow_move_constructible<__first_node>::value&&
729          is_nothrow_move_constructible<__node_allocator>::value&& is_nothrow_move_constructible<hasher>::value&&
730              is_nothrow_move_constructible<key_equal>::value);
731  _LIBCPP_HIDE_FROM_ABI __hash_table(__hash_table&& __u, const allocator_type& __a);
732  _LIBCPP_HIDE_FROM_ABI ~__hash_table();
733
734  _LIBCPP_HIDE_FROM_ABI __hash_table& operator=(const __hash_table& __u);
735  _LIBCPP_HIDE_FROM_ABI __hash_table& operator=(__hash_table&& __u)
736      _NOEXCEPT_(__node_traits::propagate_on_container_move_assignment::value&&
737                     is_nothrow_move_assignable<__node_allocator>::value&& is_nothrow_move_assignable<hasher>::value&&
738                         is_nothrow_move_assignable<key_equal>::value);
739  template <class _InputIterator>
740  _LIBCPP_HIDE_FROM_ABI void __assign_unique(_InputIterator __first, _InputIterator __last);
741  template <class _InputIterator>
742  _LIBCPP_HIDE_FROM_ABI void __assign_multi(_InputIterator __first, _InputIterator __last);
743
744  _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT {
745    return std::min<size_type>(__node_traits::max_size(__node_alloc()), numeric_limits<difference_type >::max());
746  }
747
748private:
749  _LIBCPP_HIDE_FROM_ABI __next_pointer __node_insert_multi_prepare(size_t __cp_hash, value_type& __cp_val);
750  _LIBCPP_HIDE_FROM_ABI void __node_insert_multi_perform(__node_pointer __cp, __next_pointer __pn) _NOEXCEPT;
751
752  _LIBCPP_HIDE_FROM_ABI __next_pointer __node_insert_unique_prepare(size_t __nd_hash, value_type& __nd_val);
753  _LIBCPP_HIDE_FROM_ABI void __node_insert_unique_perform(__node_pointer __ptr) _NOEXCEPT;
754
755public:
756  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __node_insert_unique(__node_pointer __nd);
757  _LIBCPP_HIDE_FROM_ABI iterator __node_insert_multi(__node_pointer __nd);
758  _LIBCPP_HIDE_FROM_ABI iterator __node_insert_multi(const_iterator __p, __node_pointer __nd);
759
760  template <class _Key, class... _Args>
761  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique_key_args(_Key const& __k, _Args&&... __args);
762
763  template <class... _Args>
764  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique_impl(_Args&&... __args);
765
766  template <class _Pp>
767  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique(_Pp&& __x) {
768    return __emplace_unique_extract_key(std::forward<_Pp>(__x), __can_extract_key<_Pp, key_type>());
769  }
770
771  template <class _First,
772            class _Second,
773            __enable_if_t<__can_extract_map_key<_First, key_type, __container_value_type>::value, int> = 0>
774  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique(_First&& __f, _Second&& __s) {
775    return __emplace_unique_key_args(__f, std::forward<_First>(__f), std::forward<_Second>(__s));
776  }
777
778  template <class... _Args>
779  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique(_Args&&... __args) {
780    return __emplace_unique_impl(std::forward<_Args>(__args)...);
781  }
782
783  template <class _Pp>
784  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique_extract_key(_Pp&& __x, __extract_key_fail_tag) {
785    return __emplace_unique_impl(std::forward<_Pp>(__x));
786  }
787  template <class _Pp>
788  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique_extract_key(_Pp&& __x, __extract_key_self_tag) {
789    return __emplace_unique_key_args(__x, std::forward<_Pp>(__x));
790  }
791  template <class _Pp>
792  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __emplace_unique_extract_key(_Pp&& __x, __extract_key_first_tag) {
793    return __emplace_unique_key_args(__x.first, std::forward<_Pp>(__x));
794  }
795
796  template <class... _Args>
797  _LIBCPP_HIDE_FROM_ABI iterator __emplace_multi(_Args&&... __args);
798  template <class... _Args>
799  _LIBCPP_HIDE_FROM_ABI iterator __emplace_hint_multi(const_iterator __p, _Args&&... __args);
800
801  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __insert_unique(__container_value_type&& __x) {
802    return __emplace_unique_key_args(_NodeTypes::__get_key(__x), std::move(__x));
803  }
804
805  template <class _Pp, class = __enable_if_t<!__is_same_uncvref<_Pp, __container_value_type>::value> >
806  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __insert_unique(_Pp&& __x) {
807    return __emplace_unique(std::forward<_Pp>(__x));
808  }
809
810  template <class _Pp>
811  _LIBCPP_HIDE_FROM_ABI iterator __insert_multi(_Pp&& __x) {
812    return __emplace_multi(std::forward<_Pp>(__x));
813  }
814
815  template <class _Pp>
816  _LIBCPP_HIDE_FROM_ABI iterator __insert_multi(const_iterator __p, _Pp&& __x) {
817    return __emplace_hint_multi(__p, std::forward<_Pp>(__x));
818  }
819
820  _LIBCPP_HIDE_FROM_ABI pair<iterator, bool> __insert_unique(const __container_value_type& __x) {
821    return __emplace_unique_key_args(_NodeTypes::__get_key(__x), __x);
822  }
823
824#if _LIBCPP_STD_VER >= 17
825  template <class _NodeHandle, class _InsertReturnType>
826  _LIBCPP_HIDE_FROM_ABI _InsertReturnType __node_handle_insert_unique(_NodeHandle&& __nh);
827  template <class _NodeHandle>
828  _LIBCPP_HIDE_FROM_ABI iterator __node_handle_insert_unique(const_iterator __hint, _NodeHandle&& __nh);
829  template <class _Table>
830  _LIBCPP_HIDE_FROM_ABI void __node_handle_merge_unique(_Table& __source);
831
832  template <class _NodeHandle>
833  _LIBCPP_HIDE_FROM_ABI iterator __node_handle_insert_multi(_NodeHandle&& __nh);
834  template <class _NodeHandle>
835  _LIBCPP_HIDE_FROM_ABI iterator __node_handle_insert_multi(const_iterator __hint, _NodeHandle&& __nh);
836  template <class _Table>
837  _LIBCPP_HIDE_FROM_ABI void __node_handle_merge_multi(_Table& __source);
838
839  template <class _NodeHandle>
840  _LIBCPP_HIDE_FROM_ABI _NodeHandle __node_handle_extract(key_type const& __key);
841  template <class _NodeHandle>
842  _LIBCPP_HIDE_FROM_ABI _NodeHandle __node_handle_extract(const_iterator __it);
843#endif
844
845  _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT;
846  _LIBCPP_HIDE_FROM_ABI void __rehash_unique(size_type __n) { __rehash<true>(__n); }
847  _LIBCPP_HIDE_FROM_ABI void __rehash_multi(size_type __n) { __rehash<false>(__n); }
848  _LIBCPP_HIDE_FROM_ABI void __reserve_unique(size_type __n) {
849    __rehash_unique(static_cast<size_type>(std::ceil(__n / max_load_factor())));
850  }
851  _LIBCPP_HIDE_FROM_ABI void __reserve_multi(size_type __n) {
852    __rehash_multi(static_cast<size_type>(std::ceil(__n / max_load_factor())));
853  }
854
855  _LIBCPP_HIDE_FROM_ABI size_type bucket_count() const _NOEXCEPT { return __bucket_list_.get_deleter().size(); }
856
857  _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT;
858  _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT;
859  _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT;
860  _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT;
861
862  template <class _Key>
863  _LIBCPP_HIDE_FROM_ABI size_type bucket(const _Key& __k) const {
864    _LIBCPP_ASSERT_ARGUMENT_WITHIN_DOMAIN(
865        bucket_count() > 0, "unordered container::bucket(key) called when bucket_count() == 0");
866    return std::__constrain_hash(hash_function()(__k), bucket_count());
867  }
868
869  template <class _Key>
870  _LIBCPP_HIDE_FROM_ABI iterator find(const _Key& __x);
871  template <class _Key>
872  _LIBCPP_HIDE_FROM_ABI const_iterator find(const _Key& __x) const;
873
874  typedef __hash_node_destructor<__node_allocator> _Dp;
875  typedef unique_ptr<__node, _Dp> __node_holder;
876
877  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __p);
878  _LIBCPP_HIDE_FROM_ABI iterator erase(const_iterator __first, const_iterator __last);
879  template <class _Key>
880  _LIBCPP_HIDE_FROM_ABI size_type __erase_unique(const _Key& __k);
881  template <class _Key>
882  _LIBCPP_HIDE_FROM_ABI size_type __erase_multi(const _Key& __k);
883  _LIBCPP_HIDE_FROM_ABI __node_holder remove(const_iterator __p) _NOEXCEPT;
884
885  template <class _Key>
886  _LIBCPP_HIDE_FROM_ABI size_type __count_unique(const _Key& __k) const;
887  template <class _Key>
888  _LIBCPP_HIDE_FROM_ABI size_type __count_multi(const _Key& __k) const;
889
890  template <class _Key>
891  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> __equal_range_unique(const _Key& __k);
892  template <class _Key>
893  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> __equal_range_unique(const _Key& __k) const;
894
895  template <class _Key>
896  _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> __equal_range_multi(const _Key& __k);
897  template <class _Key>
898  _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> __equal_range_multi(const _Key& __k) const;
899
900  _LIBCPP_HIDE_FROM_ABI void swap(__hash_table& __u)
901#if _LIBCPP_STD_VER <= 11
902      _NOEXCEPT_(__is_nothrow_swappable<hasher>::value&& __is_nothrow_swappable<key_equal>::value &&
903                 (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value ||
904                  __is_nothrow_swappable<__pointer_allocator>::value) &&
905                 (!__node_traits::propagate_on_container_swap::value ||
906                  __is_nothrow_swappable<__node_allocator>::value));
907#else
908      _NOEXCEPT_(__is_nothrow_swappable<hasher>::value&& __is_nothrow_swappable<key_equal>::value);
909#endif
910
911  _LIBCPP_HIDE_FROM_ABI size_type max_bucket_count() const _NOEXCEPT { return max_size(); }
912  _LIBCPP_HIDE_FROM_ABI size_type bucket_size(size_type __n) const;
913  _LIBCPP_HIDE_FROM_ABI float load_factor() const _NOEXCEPT {
914    size_type __bc = bucket_count();
915    return __bc != 0 ? (float)size() / __bc : 0.f;
916  }
917  _LIBCPP_HIDE_FROM_ABI void max_load_factor(float __mlf) _NOEXCEPT {
918    // While passing a non-positive load factor is undefined behavior, in practice the result will be benign (the
919    // call will be equivalent to `max_load_factor(load_factor())`, which is also the case for passing a valid value
920    // less than the current `load_factor`).
921    _LIBCPP_ASSERT_PEDANTIC(__mlf > 0, "unordered container::max_load_factor(lf) called with lf <= 0");
922    max_load_factor() = std::max(__mlf, load_factor());
923  }
924
925  _LIBCPP_HIDE_FROM_ABI local_iterator begin(size_type __n) {
926    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
927        __n < bucket_count(), "unordered container::begin(n) called with n >= bucket_count()");
928    return local_iterator(__bucket_list_[__n], __n, bucket_count());
929  }
930
931  _LIBCPP_HIDE_FROM_ABI local_iterator end(size_type __n) {
932    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
933        __n < bucket_count(), "unordered container::end(n) called with n >= bucket_count()");
934    return local_iterator(nullptr, __n, bucket_count());
935  }
936
937  _LIBCPP_HIDE_FROM_ABI const_local_iterator cbegin(size_type __n) const {
938    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
939        __n < bucket_count(), "unordered container::cbegin(n) called with n >= bucket_count()");
940    return const_local_iterator(__bucket_list_[__n], __n, bucket_count());
941  }
942
943  _LIBCPP_HIDE_FROM_ABI const_local_iterator cend(size_type __n) const {
944    _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
945        __n < bucket_count(), "unordered container::cend(n) called with n >= bucket_count()");
946    return const_local_iterator(nullptr, __n, bucket_count());
947  }
948
949private:
950  template <bool _UniqueKeys>
951  _LIBCPP_HIDE_FROM_ABI void __rehash(size_type __n);
952  template <bool _UniqueKeys>
953  _LIBCPP_HIDE_FROM_ABI void __do_rehash(size_type __n);
954
955  template <class... _Args>
956  _LIBCPP_HIDE_FROM_ABI __node_holder __construct_node(_Args&&... __args);
957
958  template <class _First, class... _Rest>
959  _LIBCPP_HIDE_FROM_ABI __node_holder __construct_node_hash(size_t __hash, _First&& __f, _Rest&&... __rest);
960
961  _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const __hash_table& __u) {
962    __copy_assign_alloc(__u, integral_constant<bool, __node_traits::propagate_on_container_copy_assignment::value>());
963  }
964  _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const __hash_table& __u, true_type);
965  _LIBCPP_HIDE_FROM_ABI void __copy_assign_alloc(const __hash_table&, false_type) {}
966
967  _LIBCPP_HIDE_FROM_ABI void __move_assign(__hash_table& __u, false_type);
968  _LIBCPP_HIDE_FROM_ABI void __move_assign(__hash_table& __u, true_type)
969      _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value&& is_nothrow_move_assignable<hasher>::value&&
970                     is_nothrow_move_assignable<key_equal>::value);
971  _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__hash_table& __u) _NOEXCEPT_(
972      !__node_traits::propagate_on_container_move_assignment::value ||
973      (is_nothrow_move_assignable<__pointer_allocator>::value && is_nothrow_move_assignable<__node_allocator>::value)) {
974    __move_assign_alloc(__u, integral_constant<bool, __node_traits::propagate_on_container_move_assignment::value>());
975  }
976  _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__hash_table& __u, true_type) _NOEXCEPT_(
977      is_nothrow_move_assignable<__pointer_allocator>::value&& is_nothrow_move_assignable<__node_allocator>::value) {
978    __bucket_list_.get_deleter().__alloc() = std::move(__u.__bucket_list_.get_deleter().__alloc());
979    __node_alloc()                         = std::move(__u.__node_alloc());
980  }
981  _LIBCPP_HIDE_FROM_ABI void __move_assign_alloc(__hash_table&, false_type) _NOEXCEPT {}
982
983  _LIBCPP_HIDE_FROM_ABI void __deallocate_node(__next_pointer __np) _NOEXCEPT;
984  _LIBCPP_HIDE_FROM_ABI __next_pointer __detach() _NOEXCEPT;
985
986  template <class, class, class, class, class>
987  friend class _LIBCPP_TEMPLATE_VIS unordered_map;
988  template <class, class, class, class, class>
989  friend class _LIBCPP_TEMPLATE_VIS unordered_multimap;
990};
991
992template <class _Tp, class _Hash, class _Equal, class _Alloc>
993inline __hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table() _NOEXCEPT_(
994    is_nothrow_default_constructible<__bucket_list>::value&& is_nothrow_default_constructible<__first_node>::value&&
995        is_nothrow_default_constructible<__node_allocator>::value&& is_nothrow_default_constructible<hasher>::value&&
996            is_nothrow_default_constructible<key_equal>::value)
997    : __p2_(0, __default_init_tag()), __p3_(1.0f, __default_init_tag()) {}
998
999template <class _Tp, class _Hash, class _Equal, class _Alloc>
1000inline __hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const hasher& __hf, const key_equal& __eql)
1001    : __bucket_list_(nullptr, __bucket_list_deleter()), __p1_(), __p2_(0, __hf), __p3_(1.0f, __eql) {}
1002
1003template <class _Tp, class _Hash, class _Equal, class _Alloc>
1004__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(
1005    const hasher& __hf, const key_equal& __eql, const allocator_type& __a)
1006    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1007      __p1_(__default_init_tag(), __node_allocator(__a)),
1008      __p2_(0, __hf),
1009      __p3_(1.0f, __eql) {}
1010
1011template <class _Tp, class _Hash, class _Equal, class _Alloc>
1012__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const allocator_type& __a)
1013    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1014      __p1_(__default_init_tag(), __node_allocator(__a)),
1015      __p2_(0, __default_init_tag()),
1016      __p3_(1.0f, __default_init_tag()) {}
1017
1018template <class _Tp, class _Hash, class _Equal, class _Alloc>
1019__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u)
1020    : __bucket_list_(nullptr,
1021                     __bucket_list_deleter(allocator_traits<__pointer_allocator>::select_on_container_copy_construction(
1022                                               __u.__bucket_list_.get_deleter().__alloc()),
1023                                           0)),
1024      __p1_(__default_init_tag(),
1025            allocator_traits<__node_allocator>::select_on_container_copy_construction(__u.__node_alloc())),
1026      __p2_(0, __u.hash_function()),
1027      __p3_(__u.__p3_) {}
1028
1029template <class _Tp, class _Hash, class _Equal, class _Alloc>
1030__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(const __hash_table& __u, const allocator_type& __a)
1031    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1032      __p1_(__default_init_tag(), __node_allocator(__a)),
1033      __p2_(0, __u.hash_function()),
1034      __p3_(__u.__p3_) {}
1035
1036template <class _Tp, class _Hash, class _Equal, class _Alloc>
1037__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u) _NOEXCEPT_(
1038    is_nothrow_move_constructible<__bucket_list>::value&& is_nothrow_move_constructible<__first_node>::value&&
1039        is_nothrow_move_constructible<__node_allocator>::value&& is_nothrow_move_constructible<hasher>::value&&
1040            is_nothrow_move_constructible<key_equal>::value)
1041    : __bucket_list_(std::move(__u.__bucket_list_)),
1042      __p1_(std::move(__u.__p1_)),
1043      __p2_(std::move(__u.__p2_)),
1044      __p3_(std::move(__u.__p3_)) {
1045  if (size() > 0) {
1046    __bucket_list_[std::__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] = __p1_.first().__ptr();
1047    __u.__p1_.first().__next_                                                              = nullptr;
1048    __u.size()                                                                             = 0;
1049  }
1050}
1051
1052template <class _Tp, class _Hash, class _Equal, class _Alloc>
1053__hash_table<_Tp, _Hash, _Equal, _Alloc>::__hash_table(__hash_table&& __u, const allocator_type& __a)
1054    : __bucket_list_(nullptr, __bucket_list_deleter(__pointer_allocator(__a), 0)),
1055      __p1_(__default_init_tag(), __node_allocator(__a)),
1056      __p2_(0, std::move(__u.hash_function())),
1057      __p3_(std::move(__u.__p3_)) {
1058  if (__a == allocator_type(__u.__node_alloc())) {
1059    __bucket_list_.reset(__u.__bucket_list_.release());
1060    __bucket_list_.get_deleter().size()     = __u.__bucket_list_.get_deleter().size();
1061    __u.__bucket_list_.get_deleter().size() = 0;
1062    if (__u.size() > 0) {
1063      __p1_.first().__next_     = __u.__p1_.first().__next_;
1064      __u.__p1_.first().__next_ = nullptr;
1065      __bucket_list_[std::__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] = __p1_.first().__ptr();
1066      size()                                                                                 = __u.size();
1067      __u.size()                                                                             = 0;
1068    }
1069  }
1070}
1071
1072template <class _Tp, class _Hash, class _Equal, class _Alloc>
1073__hash_table<_Tp, _Hash, _Equal, _Alloc>::~__hash_table() {
1074#if defined(_LIBCPP_CXX03_LANG)
1075  static_assert((is_copy_constructible<key_equal>::value), "Predicate must be copy-constructible.");
1076  static_assert((is_copy_constructible<hasher>::value), "Hasher must be copy-constructible.");
1077#endif
1078
1079  __deallocate_node(__p1_.first().__next_);
1080}
1081
1082template <class _Tp, class _Hash, class _Equal, class _Alloc>
1083void __hash_table<_Tp, _Hash, _Equal, _Alloc>::__copy_assign_alloc(const __hash_table& __u, true_type) {
1084  if (__node_alloc() != __u.__node_alloc()) {
1085    clear();
1086    __bucket_list_.reset();
1087    __bucket_list_.get_deleter().size() = 0;
1088  }
1089  __bucket_list_.get_deleter().__alloc() = __u.__bucket_list_.get_deleter().__alloc();
1090  __node_alloc()                         = __u.__node_alloc();
1091}
1092
1093template <class _Tp, class _Hash, class _Equal, class _Alloc>
1094__hash_table<_Tp, _Hash, _Equal, _Alloc>& __hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(const __hash_table& __u) {
1095  if (this != std::addressof(__u)) {
1096    __copy_assign_alloc(__u);
1097    hash_function()   = __u.hash_function();
1098    key_eq()          = __u.key_eq();
1099    max_load_factor() = __u.max_load_factor();
1100    __assign_multi(__u.begin(), __u.end());
1101  }
1102  return *this;
1103}
1104
1105template <class _Tp, class _Hash, class _Equal, class _Alloc>
1106void __hash_table<_Tp, _Hash, _Equal, _Alloc>::__deallocate_node(__next_pointer __np) _NOEXCEPT {
1107  __node_allocator& __na = __node_alloc();
1108  while (__np != nullptr) {
1109    __next_pointer __next    = __np->__next_;
1110    __node_pointer __real_np = __np->__upcast();
1111    __node_traits::destroy(__na, _NodeTypes::__get_ptr(__real_np->__get_value()));
1112    std::__destroy_at(std::addressof(*__real_np));
1113    __node_traits::deallocate(__na, __real_np, 1);
1114    __np = __next;
1115  }
1116}
1117
1118template <class _Tp, class _Hash, class _Equal, class _Alloc>
1119typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1120__hash_table<_Tp, _Hash, _Equal, _Alloc>::__detach() _NOEXCEPT {
1121  size_type __bc = bucket_count();
1122  for (size_type __i = 0; __i < __bc; ++__i)
1123    __bucket_list_[__i] = nullptr;
1124  size()                 = 0;
1125  __next_pointer __cache = __p1_.first().__next_;
1126  __p1_.first().__next_  = nullptr;
1127  return __cache;
1128}
1129
1130template <class _Tp, class _Hash, class _Equal, class _Alloc>
1131void __hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(__hash_table& __u, true_type)
1132    _NOEXCEPT_(is_nothrow_move_assignable<__node_allocator>::value&& is_nothrow_move_assignable<hasher>::value&&
1133                   is_nothrow_move_assignable<key_equal>::value) {
1134  clear();
1135  __bucket_list_.reset(__u.__bucket_list_.release());
1136  __bucket_list_.get_deleter().size()     = __u.__bucket_list_.get_deleter().size();
1137  __u.__bucket_list_.get_deleter().size() = 0;
1138  __move_assign_alloc(__u);
1139  size()                = __u.size();
1140  hash_function()       = std::move(__u.hash_function());
1141  max_load_factor()     = __u.max_load_factor();
1142  key_eq()              = std::move(__u.key_eq());
1143  __p1_.first().__next_ = __u.__p1_.first().__next_;
1144  if (size() > 0) {
1145    __bucket_list_[std::__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] = __p1_.first().__ptr();
1146    __u.__p1_.first().__next_                                                              = nullptr;
1147    __u.size()                                                                             = 0;
1148  }
1149}
1150
1151template <class _Tp, class _Hash, class _Equal, class _Alloc>
1152void __hash_table<_Tp, _Hash, _Equal, _Alloc>::__move_assign(__hash_table& __u, false_type) {
1153  if (__node_alloc() == __u.__node_alloc())
1154    __move_assign(__u, true_type());
1155  else {
1156    hash_function()   = std::move(__u.hash_function());
1157    key_eq()          = std::move(__u.key_eq());
1158    max_load_factor() = __u.max_load_factor();
1159    if (bucket_count() != 0) {
1160      __next_pointer __cache = __detach();
1161#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1162      try {
1163#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1164        const_iterator __i = __u.begin();
1165        while (__cache != nullptr && __u.size() != 0) {
1166          __cache->__upcast()->__get_value() = std::move(__u.remove(__i++)->__get_value());
1167          __next_pointer __next              = __cache->__next_;
1168          __node_insert_multi(__cache->__upcast());
1169          __cache = __next;
1170        }
1171#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1172      } catch (...) {
1173        __deallocate_node(__cache);
1174        throw;
1175      }
1176#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1177      __deallocate_node(__cache);
1178    }
1179    const_iterator __i = __u.begin();
1180    while (__u.size() != 0) {
1181      __node_holder __h = __construct_node(_NodeTypes::__move(__u.remove(__i++)->__get_value()));
1182      __node_insert_multi(__h.get());
1183      __h.release();
1184    }
1185  }
1186}
1187
1188template <class _Tp, class _Hash, class _Equal, class _Alloc>
1189inline __hash_table<_Tp, _Hash, _Equal, _Alloc>&
1190__hash_table<_Tp, _Hash, _Equal, _Alloc>::operator=(__hash_table&& __u) _NOEXCEPT_(
1191    __node_traits::propagate_on_container_move_assignment::value&& is_nothrow_move_assignable<__node_allocator>::value&&
1192        is_nothrow_move_assignable<hasher>::value&& is_nothrow_move_assignable<key_equal>::value) {
1193  __move_assign(__u, integral_constant<bool, __node_traits::propagate_on_container_move_assignment::value>());
1194  return *this;
1195}
1196
1197template <class _Tp, class _Hash, class _Equal, class _Alloc>
1198template <class _InputIterator>
1199void __hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_unique(_InputIterator __first, _InputIterator __last) {
1200  typedef iterator_traits<_InputIterator> _ITraits;
1201  typedef typename _ITraits::value_type _ItValueType;
1202  static_assert((is_same<_ItValueType, __container_value_type>::value),
1203                "__assign_unique may only be called with the containers value type");
1204
1205  if (bucket_count() != 0) {
1206    __next_pointer __cache = __detach();
1207#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1208    try {
1209#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1210      for (; __cache != nullptr && __first != __last; ++__first) {
1211        __cache->__upcast()->__get_value() = *__first;
1212        __next_pointer __next              = __cache->__next_;
1213        __node_insert_unique(__cache->__upcast());
1214        __cache = __next;
1215      }
1216#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1217    } catch (...) {
1218      __deallocate_node(__cache);
1219      throw;
1220    }
1221#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1222    __deallocate_node(__cache);
1223  }
1224  for (; __first != __last; ++__first)
1225    __insert_unique(*__first);
1226}
1227
1228template <class _Tp, class _Hash, class _Equal, class _Alloc>
1229template <class _InputIterator>
1230void __hash_table<_Tp, _Hash, _Equal, _Alloc>::__assign_multi(_InputIterator __first, _InputIterator __last) {
1231  typedef iterator_traits<_InputIterator> _ITraits;
1232  typedef typename _ITraits::value_type _ItValueType;
1233  static_assert(
1234      (is_same<_ItValueType, __container_value_type>::value || is_same<_ItValueType, __node_value_type>::value),
1235      "__assign_multi may only be called with the containers value type"
1236      " or the nodes value type");
1237  if (bucket_count() != 0) {
1238    __next_pointer __cache = __detach();
1239#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1240    try {
1241#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1242      for (; __cache != nullptr && __first != __last; ++__first) {
1243        __cache->__upcast()->__get_value() = *__first;
1244        __next_pointer __next              = __cache->__next_;
1245        __node_insert_multi(__cache->__upcast());
1246        __cache = __next;
1247      }
1248#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
1249    } catch (...) {
1250      __deallocate_node(__cache);
1251      throw;
1252    }
1253#endif // _LIBCPP_HAS_NO_EXCEPTIONS
1254    __deallocate_node(__cache);
1255  }
1256  for (; __first != __last; ++__first)
1257    __insert_multi(_NodeTypes::__get_value(*__first));
1258}
1259
1260template <class _Tp, class _Hash, class _Equal, class _Alloc>
1261inline typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1262__hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() _NOEXCEPT {
1263  return iterator(__p1_.first().__next_);
1264}
1265
1266template <class _Tp, class _Hash, class _Equal, class _Alloc>
1267inline typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1268__hash_table<_Tp, _Hash, _Equal, _Alloc>::end() _NOEXCEPT {
1269  return iterator(nullptr);
1270}
1271
1272template <class _Tp, class _Hash, class _Equal, class _Alloc>
1273inline typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
1274__hash_table<_Tp, _Hash, _Equal, _Alloc>::begin() const _NOEXCEPT {
1275  return const_iterator(__p1_.first().__next_);
1276}
1277
1278template <class _Tp, class _Hash, class _Equal, class _Alloc>
1279inline typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
1280__hash_table<_Tp, _Hash, _Equal, _Alloc>::end() const _NOEXCEPT {
1281  return const_iterator(nullptr);
1282}
1283
1284template <class _Tp, class _Hash, class _Equal, class _Alloc>
1285void __hash_table<_Tp, _Hash, _Equal, _Alloc>::clear() _NOEXCEPT {
1286  if (size() > 0) {
1287    __deallocate_node(__p1_.first().__next_);
1288    __p1_.first().__next_ = nullptr;
1289    size_type __bc        = bucket_count();
1290    for (size_type __i = 0; __i < __bc; ++__i)
1291      __bucket_list_[__i] = nullptr;
1292    size() = 0;
1293  }
1294}
1295
1296// Prepare the container for an insertion of the value __value with the hash
1297// __hash. This does a lookup into the container to see if __value is already
1298// present, and performs a rehash if necessary. Returns a pointer to the
1299// existing element if it exists, otherwise nullptr.
1300//
1301// Note that this function does forward exceptions if key_eq() throws, and never
1302// mutates __value or actually inserts into the map.
1303template <class _Tp, class _Hash, class _Equal, class _Alloc>
1304_LIBCPP_HIDE_FROM_ABI typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1305__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique_prepare(size_t __hash, value_type& __value) {
1306  size_type __bc = bucket_count();
1307
1308  if (__bc != 0) {
1309    size_t __chash         = std::__constrain_hash(__hash, __bc);
1310    __next_pointer __ndptr = __bucket_list_[__chash];
1311    if (__ndptr != nullptr) {
1312      for (__ndptr = __ndptr->__next_;
1313           __ndptr != nullptr &&
1314           (__ndptr->__hash() == __hash || std::__constrain_hash(__ndptr->__hash(), __bc) == __chash);
1315           __ndptr = __ndptr->__next_) {
1316        if ((__ndptr->__hash() == __hash) && key_eq()(__ndptr->__upcast()->__get_value(), __value))
1317          return __ndptr;
1318      }
1319    }
1320  }
1321  if (size() + 1 > __bc * max_load_factor() || __bc == 0) {
1322    __rehash_unique(std::max<size_type>(
1323        2 * __bc + !std::__is_hash_power2(__bc), size_type(std::ceil(float(size() + 1) / max_load_factor()))));
1324  }
1325  return nullptr;
1326}
1327
1328// Insert the node __nd into the container by pushing it into the right bucket,
1329// and updating size(). Assumes that __nd->__hash is up-to-date, and that
1330// rehashing has already occurred and that no element with the same key exists
1331// in the map.
1332template <class _Tp, class _Hash, class _Equal, class _Alloc>
1333_LIBCPP_HIDE_FROM_ABI void
1334__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique_perform(__node_pointer __nd) _NOEXCEPT {
1335  size_type __bc = bucket_count();
1336  size_t __chash = std::__constrain_hash(__nd->__hash(), __bc);
1337  // insert_after __bucket_list_[__chash], or __first_node if bucket is null
1338  __next_pointer __pn = __bucket_list_[__chash];
1339  if (__pn == nullptr) {
1340    __pn          = __p1_.first().__ptr();
1341    __nd->__next_ = __pn->__next_;
1342    __pn->__next_ = __nd->__ptr();
1343    // fix up __bucket_list_
1344    __bucket_list_[__chash] = __pn;
1345    if (__nd->__next_ != nullptr)
1346      __bucket_list_[std::__constrain_hash(__nd->__next_->__hash(), __bc)] = __nd->__ptr();
1347  } else {
1348    __nd->__next_ = __pn->__next_;
1349    __pn->__next_ = __nd->__ptr();
1350  }
1351  ++size();
1352}
1353
1354template <class _Tp, class _Hash, class _Equal, class _Alloc>
1355pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
1356__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_unique(__node_pointer __nd) {
1357  __nd->__hash_                  = hash_function()(__nd->__get_value());
1358  __next_pointer __existing_node = __node_insert_unique_prepare(__nd->__hash(), __nd->__get_value());
1359
1360  // Insert the node, unless it already exists in the container.
1361  bool __inserted = false;
1362  if (__existing_node == nullptr) {
1363    __node_insert_unique_perform(__nd);
1364    __existing_node = __nd->__ptr();
1365    __inserted      = true;
1366  }
1367  return pair<iterator, bool>(iterator(__existing_node), __inserted);
1368}
1369
1370// Prepare the container for an insertion of the value __cp_val with the hash
1371// __cp_hash. This does a lookup into the container to see if __cp_value is
1372// already present, and performs a rehash if necessary. Returns a pointer to the
1373// last occurrence of __cp_val in the map.
1374//
1375// Note that this function does forward exceptions if key_eq() throws, and never
1376// mutates __value or actually inserts into the map.
1377template <class _Tp, class _Hash, class _Equal, class _Alloc>
1378typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__next_pointer
1379__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi_prepare(size_t __cp_hash, value_type& __cp_val) {
1380  size_type __bc = bucket_count();
1381  if (size() + 1 > __bc * max_load_factor() || __bc == 0) {
1382    __rehash_multi(std::max<size_type>(
1383        2 * __bc + !std::__is_hash_power2(__bc), size_type(std::ceil(float(size() + 1) / max_load_factor()))));
1384    __bc = bucket_count();
1385  }
1386  size_t __chash      = std::__constrain_hash(__cp_hash, __bc);
1387  __next_pointer __pn = __bucket_list_[__chash];
1388  if (__pn != nullptr) {
1389    for (bool __found = false;
1390         __pn->__next_ != nullptr && std::__constrain_hash(__pn->__next_->__hash(), __bc) == __chash;
1391         __pn = __pn->__next_) {
1392      //      __found    key_eq()     action
1393      //      false       false       loop
1394      //      true        true        loop
1395      //      false       true        set __found to true
1396      //      true        false       break
1397      if (__found !=
1398          (__pn->__next_->__hash() == __cp_hash && key_eq()(__pn->__next_->__upcast()->__get_value(), __cp_val))) {
1399        if (!__found)
1400          __found = true;
1401        else
1402          break;
1403      }
1404    }
1405  }
1406  return __pn;
1407}
1408
1409// Insert the node __cp into the container after __pn (which is the last node in
1410// the bucket that compares equal to __cp). Rehashing, and checking for
1411// uniqueness has already been performed (in __node_insert_multi_prepare), so
1412// all we need to do is update the bucket and size(). Assumes that __cp->__hash
1413// is up-to-date.
1414template <class _Tp, class _Hash, class _Equal, class _Alloc>
1415void __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi_perform(
1416    __node_pointer __cp, __next_pointer __pn) _NOEXCEPT {
1417  size_type __bc = bucket_count();
1418  size_t __chash = std::__constrain_hash(__cp->__hash_, __bc);
1419  if (__pn == nullptr) {
1420    __pn          = __p1_.first().__ptr();
1421    __cp->__next_ = __pn->__next_;
1422    __pn->__next_ = __cp->__ptr();
1423    // fix up __bucket_list_
1424    __bucket_list_[__chash] = __pn;
1425    if (__cp->__next_ != nullptr)
1426      __bucket_list_[std::__constrain_hash(__cp->__next_->__hash(), __bc)] = __cp->__ptr();
1427  } else {
1428    __cp->__next_ = __pn->__next_;
1429    __pn->__next_ = __cp->__ptr();
1430    if (__cp->__next_ != nullptr) {
1431      size_t __nhash = std::__constrain_hash(__cp->__next_->__hash(), __bc);
1432      if (__nhash != __chash)
1433        __bucket_list_[__nhash] = __cp->__ptr();
1434    }
1435  }
1436  ++size();
1437}
1438
1439template <class _Tp, class _Hash, class _Equal, class _Alloc>
1440typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1441__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(__node_pointer __cp) {
1442  __cp->__hash_       = hash_function()(__cp->__get_value());
1443  __next_pointer __pn = __node_insert_multi_prepare(__cp->__hash(), __cp->__get_value());
1444  __node_insert_multi_perform(__cp, __pn);
1445
1446  return iterator(__cp->__ptr());
1447}
1448
1449template <class _Tp, class _Hash, class _Equal, class _Alloc>
1450typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1451__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_insert_multi(const_iterator __p, __node_pointer __cp) {
1452  if (__p != end() && key_eq()(*__p, __cp->__get_value())) {
1453    __next_pointer __np = __p.__node_;
1454    __cp->__hash_       = __np->__hash();
1455    size_type __bc      = bucket_count();
1456    if (size() + 1 > __bc * max_load_factor() || __bc == 0) {
1457      __rehash_multi(std::max<size_type>(
1458          2 * __bc + !std::__is_hash_power2(__bc), size_type(std::ceil(float(size() + 1) / max_load_factor()))));
1459      __bc = bucket_count();
1460    }
1461    size_t __chash      = std::__constrain_hash(__cp->__hash_, __bc);
1462    __next_pointer __pp = __bucket_list_[__chash];
1463    while (__pp->__next_ != __np)
1464      __pp = __pp->__next_;
1465    __cp->__next_ = __np;
1466    __pp->__next_ = static_cast<__next_pointer>(__cp);
1467    ++size();
1468    return iterator(static_cast<__next_pointer>(__cp));
1469  }
1470  return __node_insert_multi(__cp);
1471}
1472
1473template <class _Tp, class _Hash, class _Equal, class _Alloc>
1474template <class _Key, class... _Args>
1475pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
1476__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_key_args(_Key const& __k, _Args&&... __args) {
1477  size_t __hash   = hash_function()(__k);
1478  size_type __bc  = bucket_count();
1479  bool __inserted = false;
1480  __next_pointer __nd;
1481  size_t __chash;
1482  if (__bc != 0) {
1483    __chash = std::__constrain_hash(__hash, __bc);
1484    __nd    = __bucket_list_[__chash];
1485    if (__nd != nullptr) {
1486      for (__nd = __nd->__next_;
1487           __nd != nullptr && (__nd->__hash() == __hash || std::__constrain_hash(__nd->__hash(), __bc) == __chash);
1488           __nd = __nd->__next_) {
1489        if ((__nd->__hash() == __hash) && key_eq()(__nd->__upcast()->__get_value(), __k))
1490          goto __done;
1491      }
1492    }
1493  }
1494  {
1495    __node_holder __h = __construct_node_hash(__hash, std::forward<_Args>(__args)...);
1496    if (size() + 1 > __bc * max_load_factor() || __bc == 0) {
1497      __rehash_unique(std::max<size_type>(
1498          2 * __bc + !std::__is_hash_power2(__bc), size_type(std::ceil(float(size() + 1) / max_load_factor()))));
1499      __bc    = bucket_count();
1500      __chash = std::__constrain_hash(__hash, __bc);
1501    }
1502    // insert_after __bucket_list_[__chash], or __first_node if bucket is null
1503    __next_pointer __pn = __bucket_list_[__chash];
1504    if (__pn == nullptr) {
1505      __pn          = __p1_.first().__ptr();
1506      __h->__next_  = __pn->__next_;
1507      __pn->__next_ = __h.get()->__ptr();
1508      // fix up __bucket_list_
1509      __bucket_list_[__chash] = __pn;
1510      if (__h->__next_ != nullptr)
1511        __bucket_list_[std::__constrain_hash(__h->__next_->__hash(), __bc)] = __h.get()->__ptr();
1512    } else {
1513      __h->__next_  = __pn->__next_;
1514      __pn->__next_ = static_cast<__next_pointer>(__h.get());
1515    }
1516    __nd = static_cast<__next_pointer>(__h.release());
1517    // increment size
1518    ++size();
1519    __inserted = true;
1520  }
1521__done:
1522  return pair<iterator, bool>(iterator(__nd), __inserted);
1523}
1524
1525template <class _Tp, class _Hash, class _Equal, class _Alloc>
1526template <class... _Args>
1527pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator, bool>
1528__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_unique_impl(_Args&&... __args) {
1529  __node_holder __h        = __construct_node(std::forward<_Args>(__args)...);
1530  pair<iterator, bool> __r = __node_insert_unique(__h.get());
1531  if (__r.second)
1532    __h.release();
1533  return __r;
1534}
1535
1536template <class _Tp, class _Hash, class _Equal, class _Alloc>
1537template <class... _Args>
1538typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1539__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_multi(_Args&&... __args) {
1540  __node_holder __h = __construct_node(std::forward<_Args>(__args)...);
1541  iterator __r      = __node_insert_multi(__h.get());
1542  __h.release();
1543  return __r;
1544}
1545
1546template <class _Tp, class _Hash, class _Equal, class _Alloc>
1547template <class... _Args>
1548typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1549__hash_table<_Tp, _Hash, _Equal, _Alloc>::__emplace_hint_multi(const_iterator __p, _Args&&... __args) {
1550  __node_holder __h = __construct_node(std::forward<_Args>(__args)...);
1551  iterator __r      = __node_insert_multi(__p, __h.get());
1552  __h.release();
1553  return __r;
1554}
1555
1556#if _LIBCPP_STD_VER >= 17
1557template <class _Tp, class _Hash, class _Equal, class _Alloc>
1558template <class _NodeHandle, class _InsertReturnType>
1559_LIBCPP_HIDE_FROM_ABI _InsertReturnType
1560__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_unique(_NodeHandle&& __nh) {
1561  if (__nh.empty())
1562    return _InsertReturnType{end(), false, _NodeHandle()};
1563  pair<iterator, bool> __result = __node_insert_unique(__nh.__ptr_);
1564  if (__result.second)
1565    __nh.__release_ptr();
1566  return _InsertReturnType{__result.first, __result.second, std::move(__nh)};
1567}
1568
1569template <class _Tp, class _Hash, class _Equal, class _Alloc>
1570template <class _NodeHandle>
1571_LIBCPP_HIDE_FROM_ABI typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1572__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_unique(const_iterator, _NodeHandle&& __nh) {
1573  if (__nh.empty())
1574    return end();
1575  pair<iterator, bool> __result = __node_insert_unique(__nh.__ptr_);
1576  if (__result.second)
1577    __nh.__release_ptr();
1578  return __result.first;
1579}
1580
1581template <class _Tp, class _Hash, class _Equal, class _Alloc>
1582template <class _NodeHandle>
1583_LIBCPP_HIDE_FROM_ABI _NodeHandle
1584__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_extract(key_type const& __key) {
1585  iterator __i = find(__key);
1586  if (__i == end())
1587    return _NodeHandle();
1588  return __node_handle_extract<_NodeHandle>(__i);
1589}
1590
1591template <class _Tp, class _Hash, class _Equal, class _Alloc>
1592template <class _NodeHandle>
1593_LIBCPP_HIDE_FROM_ABI _NodeHandle __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_extract(const_iterator __p) {
1594  allocator_type __alloc(__node_alloc());
1595  return _NodeHandle(remove(__p).release(), __alloc);
1596}
1597
1598template <class _Tp, class _Hash, class _Equal, class _Alloc>
1599template <class _Table>
1600_LIBCPP_HIDE_FROM_ABI void __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_merge_unique(_Table& __source) {
1601  static_assert(is_same<__node, typename _Table::__node>::value, "");
1602
1603  for (typename _Table::iterator __it = __source.begin(); __it != __source.end();) {
1604    __node_pointer __src_ptr       = __it.__node_->__upcast();
1605    size_t __hash                  = hash_function()(__src_ptr->__get_value());
1606    __next_pointer __existing_node = __node_insert_unique_prepare(__hash, __src_ptr->__get_value());
1607    auto __prev_iter               = __it++;
1608    if (__existing_node == nullptr) {
1609      (void)__source.remove(__prev_iter).release();
1610      __src_ptr->__hash_ = __hash;
1611      __node_insert_unique_perform(__src_ptr);
1612    }
1613  }
1614}
1615
1616template <class _Tp, class _Hash, class _Equal, class _Alloc>
1617template <class _NodeHandle>
1618_LIBCPP_HIDE_FROM_ABI typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1619__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_multi(_NodeHandle&& __nh) {
1620  if (__nh.empty())
1621    return end();
1622  iterator __result = __node_insert_multi(__nh.__ptr_);
1623  __nh.__release_ptr();
1624  return __result;
1625}
1626
1627template <class _Tp, class _Hash, class _Equal, class _Alloc>
1628template <class _NodeHandle>
1629_LIBCPP_HIDE_FROM_ABI typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1630__hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_insert_multi(const_iterator __hint, _NodeHandle&& __nh) {
1631  if (__nh.empty())
1632    return end();
1633  iterator __result = __node_insert_multi(__hint, __nh.__ptr_);
1634  __nh.__release_ptr();
1635  return __result;
1636}
1637
1638template <class _Tp, class _Hash, class _Equal, class _Alloc>
1639template <class _Table>
1640_LIBCPP_HIDE_FROM_ABI void __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_handle_merge_multi(_Table& __source) {
1641  static_assert(is_same<typename _Table::__node, __node>::value, "");
1642
1643  for (typename _Table::iterator __it = __source.begin(); __it != __source.end();) {
1644    __node_pointer __src_ptr = __it.__node_->__upcast();
1645    size_t __src_hash        = hash_function()(__src_ptr->__get_value());
1646    __next_pointer __pn      = __node_insert_multi_prepare(__src_hash, __src_ptr->__get_value());
1647    (void)__source.remove(__it++).release();
1648    __src_ptr->__hash_ = __src_hash;
1649    __node_insert_multi_perform(__src_ptr, __pn);
1650  }
1651}
1652#endif // _LIBCPP_STD_VER >= 17
1653
1654template <class _Tp, class _Hash, class _Equal, class _Alloc>
1655template <bool _UniqueKeys>
1656void __hash_table<_Tp, _Hash, _Equal, _Alloc>::__rehash(size_type __n) _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK {
1657  if (__n == 1)
1658    __n = 2;
1659  else if (__n & (__n - 1))
1660    __n = std::__next_prime(__n);
1661  size_type __bc = bucket_count();
1662  if (__n > __bc)
1663    __do_rehash<_UniqueKeys>(__n);
1664  else if (__n < __bc) {
1665    __n = std::max<size_type>(
1666        __n,
1667        std::__is_hash_power2(__bc) ? std::__next_hash_pow2(size_t(std::ceil(float(size()) / max_load_factor())))
1668                                    : std::__next_prime(size_t(std::ceil(float(size()) / max_load_factor()))));
1669    if (__n < __bc)
1670      __do_rehash<_UniqueKeys>(__n);
1671  }
1672}
1673
1674template <class _Tp, class _Hash, class _Equal, class _Alloc>
1675template <bool _UniqueKeys>
1676void __hash_table<_Tp, _Hash, _Equal, _Alloc>::__do_rehash(size_type __nbc) {
1677  __pointer_allocator& __npa = __bucket_list_.get_deleter().__alloc();
1678  __bucket_list_.reset(__nbc > 0 ? __pointer_alloc_traits::allocate(__npa, __nbc) : nullptr);
1679  __bucket_list_.get_deleter().size() = __nbc;
1680  if (__nbc > 0) {
1681    for (size_type __i = 0; __i < __nbc; ++__i)
1682      __bucket_list_[__i] = nullptr;
1683    __next_pointer __pp = __p1_.first().__ptr();
1684    __next_pointer __cp = __pp->__next_;
1685    if (__cp != nullptr) {
1686      size_type __chash       = std::__constrain_hash(__cp->__hash(), __nbc);
1687      __bucket_list_[__chash] = __pp;
1688      size_type __phash       = __chash;
1689      for (__pp = __cp, void(), __cp = __cp->__next_; __cp != nullptr; __cp = __pp->__next_) {
1690        __chash = std::__constrain_hash(__cp->__hash(), __nbc);
1691        if (__chash == __phash)
1692          __pp = __cp;
1693        else {
1694          if (__bucket_list_[__chash] == nullptr) {
1695            __bucket_list_[__chash] = __pp;
1696            __pp                    = __cp;
1697            __phash                 = __chash;
1698          } else {
1699            __next_pointer __np = __cp;
1700            if _LIBCPP_CONSTEXPR_SINCE_CXX17 (!_UniqueKeys) {
1701              for (; __np->__next_ != nullptr &&
1702                     key_eq()(__cp->__upcast()->__get_value(), __np->__next_->__upcast()->__get_value());
1703                   __np = __np->__next_)
1704                ;
1705            }
1706            __pp->__next_                    = __np->__next_;
1707            __np->__next_                    = __bucket_list_[__chash]->__next_;
1708            __bucket_list_[__chash]->__next_ = __cp;
1709          }
1710        }
1711      }
1712    }
1713  }
1714}
1715
1716template <class _Tp, class _Hash, class _Equal, class _Alloc>
1717template <class _Key>
1718typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1719__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k) {
1720  size_t __hash  = hash_function()(__k);
1721  size_type __bc = bucket_count();
1722  if (__bc != 0) {
1723    size_t __chash      = std::__constrain_hash(__hash, __bc);
1724    __next_pointer __nd = __bucket_list_[__chash];
1725    if (__nd != nullptr) {
1726      for (__nd = __nd->__next_;
1727           __nd != nullptr && (__nd->__hash() == __hash || std::__constrain_hash(__nd->__hash(), __bc) == __chash);
1728           __nd = __nd->__next_) {
1729        if ((__nd->__hash() == __hash) && key_eq()(__nd->__upcast()->__get_value(), __k))
1730          return iterator(__nd);
1731      }
1732    }
1733  }
1734  return end();
1735}
1736
1737template <class _Tp, class _Hash, class _Equal, class _Alloc>
1738template <class _Key>
1739typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator
1740__hash_table<_Tp, _Hash, _Equal, _Alloc>::find(const _Key& __k) const {
1741  size_t __hash  = hash_function()(__k);
1742  size_type __bc = bucket_count();
1743  if (__bc != 0) {
1744    size_t __chash      = std::__constrain_hash(__hash, __bc);
1745    __next_pointer __nd = __bucket_list_[__chash];
1746    if (__nd != nullptr) {
1747      for (__nd = __nd->__next_;
1748           __nd != nullptr && (__hash == __nd->__hash() || std::__constrain_hash(__nd->__hash(), __bc) == __chash);
1749           __nd = __nd->__next_) {
1750        if ((__nd->__hash() == __hash) && key_eq()(__nd->__upcast()->__get_value(), __k))
1751          return const_iterator(__nd);
1752      }
1753    }
1754  }
1755  return end();
1756}
1757
1758template <class _Tp, class _Hash, class _Equal, class _Alloc>
1759template <class... _Args>
1760typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
1761__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node(_Args&&... __args) {
1762  static_assert(!__is_hash_value_type<_Args...>::value, "Construct cannot be called with a hash value type");
1763  __node_allocator& __na = __node_alloc();
1764  __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
1765
1766  // Begin the lifetime of the node itself. Note that this doesn't begin the lifetime of the value
1767  // held inside the node, since we need to use the allocator's construct() method for that.
1768  //
1769  // We don't use the allocator's construct() method to construct the node itself since the
1770  // Cpp17FooInsertable named requirements don't require the allocator's construct() method
1771  // to work on anything other than the value_type.
1772  std::__construct_at(std::addressof(*__h), /* next = */ nullptr, /* hash = */ 0);
1773
1774  // Now construct the value_type using the allocator's construct() method.
1775  __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__get_value()), std::forward<_Args>(__args)...);
1776  __h.get_deleter().__value_constructed = true;
1777
1778  __h->__hash_ = hash_function()(__h->__get_value());
1779  return __h;
1780}
1781
1782template <class _Tp, class _Hash, class _Equal, class _Alloc>
1783template <class _First, class... _Rest>
1784typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
1785__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(size_t __hash, _First&& __f, _Rest&&... __rest) {
1786  static_assert(!__is_hash_value_type<_First, _Rest...>::value, "Construct cannot be called with a hash value type");
1787  __node_allocator& __na = __node_alloc();
1788  __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
1789  std::__construct_at(std::addressof(*__h), /* next = */ nullptr, /* hash = */ __hash);
1790  __node_traits::construct(
1791      __na, _NodeTypes::__get_ptr(__h->__get_value()), std::forward<_First>(__f), std::forward<_Rest>(__rest)...);
1792  __h.get_deleter().__value_constructed = true;
1793  return __h;
1794}
1795
1796template <class _Tp, class _Hash, class _Equal, class _Alloc>
1797typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1798__hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __p) {
1799  __next_pointer __np = __p.__node_;
1800  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
1801      __p != end(), "unordered container::erase(iterator) called with a non-dereferenceable iterator");
1802  iterator __r(__np);
1803  ++__r;
1804  remove(__p);
1805  return __r;
1806}
1807
1808template <class _Tp, class _Hash, class _Equal, class _Alloc>
1809typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
1810__hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __first, const_iterator __last) {
1811  for (const_iterator __p = __first; __first != __last; __p = __first) {
1812    ++__first;
1813    erase(__p);
1814  }
1815  __next_pointer __np = __last.__node_;
1816  return iterator(__np);
1817}
1818
1819template <class _Tp, class _Hash, class _Equal, class _Alloc>
1820template <class _Key>
1821typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
1822__hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_unique(const _Key& __k) {
1823  iterator __i = find(__k);
1824  if (__i == end())
1825    return 0;
1826  erase(__i);
1827  return 1;
1828}
1829
1830template <class _Tp, class _Hash, class _Equal, class _Alloc>
1831template <class _Key>
1832typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
1833__hash_table<_Tp, _Hash, _Equal, _Alloc>::__erase_multi(const _Key& __k) {
1834  size_type __r = 0;
1835  iterator __i  = find(__k);
1836  if (__i != end()) {
1837    iterator __e = end();
1838    do {
1839      erase(__i++);
1840      ++__r;
1841    } while (__i != __e && key_eq()(*__i, __k));
1842  }
1843  return __r;
1844}
1845
1846template <class _Tp, class _Hash, class _Equal, class _Alloc>
1847typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::__node_holder
1848__hash_table<_Tp, _Hash, _Equal, _Alloc>::remove(const_iterator __p) _NOEXCEPT {
1849  // current node
1850  __next_pointer __cn = __p.__node_;
1851  size_type __bc      = bucket_count();
1852  size_t __chash      = std::__constrain_hash(__cn->__hash(), __bc);
1853  // find previous node
1854  __next_pointer __pn = __bucket_list_[__chash];
1855  for (; __pn->__next_ != __cn; __pn = __pn->__next_)
1856    ;
1857  // Fix up __bucket_list_
1858  // if __pn is not in same bucket (before begin is not in same bucket) &&
1859  //    if __cn->__next_ is not in same bucket (nullptr is not in same bucket)
1860  if (__pn == __p1_.first().__ptr() || std::__constrain_hash(__pn->__hash(), __bc) != __chash) {
1861    if (__cn->__next_ == nullptr || std::__constrain_hash(__cn->__next_->__hash(), __bc) != __chash)
1862      __bucket_list_[__chash] = nullptr;
1863  }
1864  // if __cn->__next_ is not in same bucket (nullptr is in same bucket)
1865  if (__cn->__next_ != nullptr) {
1866    size_t __nhash = std::__constrain_hash(__cn->__next_->__hash(), __bc);
1867    if (__nhash != __chash)
1868      __bucket_list_[__nhash] = __pn;
1869  }
1870  // remove __cn
1871  __pn->__next_ = __cn->__next_;
1872  __cn->__next_ = nullptr;
1873  --size();
1874  return __node_holder(__cn->__upcast(), _Dp(__node_alloc(), true));
1875}
1876
1877template <class _Tp, class _Hash, class _Equal, class _Alloc>
1878template <class _Key>
1879inline typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
1880__hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_unique(const _Key& __k) const {
1881  return static_cast<size_type>(find(__k) != end());
1882}
1883
1884template <class _Tp, class _Hash, class _Equal, class _Alloc>
1885template <class _Key>
1886typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
1887__hash_table<_Tp, _Hash, _Equal, _Alloc>::__count_multi(const _Key& __k) const {
1888  size_type __r      = 0;
1889  const_iterator __i = find(__k);
1890  if (__i != end()) {
1891    const_iterator __e = end();
1892    do {
1893      ++__i;
1894      ++__r;
1895    } while (__i != __e && key_eq()(*__i, __k));
1896  }
1897  return __r;
1898}
1899
1900template <class _Tp, class _Hash, class _Equal, class _Alloc>
1901template <class _Key>
1902pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
1903     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
1904__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(const _Key& __k) {
1905  iterator __i = find(__k);
1906  iterator __j = __i;
1907  if (__i != end())
1908    ++__j;
1909  return pair<iterator, iterator>(__i, __j);
1910}
1911
1912template <class _Tp, class _Hash, class _Equal, class _Alloc>
1913template <class _Key>
1914pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
1915     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
1916__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_unique(const _Key& __k) const {
1917  const_iterator __i = find(__k);
1918  const_iterator __j = __i;
1919  if (__i != end())
1920    ++__j;
1921  return pair<const_iterator, const_iterator>(__i, __j);
1922}
1923
1924template <class _Tp, class _Hash, class _Equal, class _Alloc>
1925template <class _Key>
1926pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator,
1927     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator>
1928__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(const _Key& __k) {
1929  iterator __i = find(__k);
1930  iterator __j = __i;
1931  if (__i != end()) {
1932    iterator __e = end();
1933    do {
1934      ++__j;
1935    } while (__j != __e && key_eq()(*__j, __k));
1936  }
1937  return pair<iterator, iterator>(__i, __j);
1938}
1939
1940template <class _Tp, class _Hash, class _Equal, class _Alloc>
1941template <class _Key>
1942pair<typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator,
1943     typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::const_iterator>
1944__hash_table<_Tp, _Hash, _Equal, _Alloc>::__equal_range_multi(const _Key& __k) const {
1945  const_iterator __i = find(__k);
1946  const_iterator __j = __i;
1947  if (__i != end()) {
1948    const_iterator __e = end();
1949    do {
1950      ++__j;
1951    } while (__j != __e && key_eq()(*__j, __k));
1952  }
1953  return pair<const_iterator, const_iterator>(__i, __j);
1954}
1955
1956template <class _Tp, class _Hash, class _Equal, class _Alloc>
1957void __hash_table<_Tp, _Hash, _Equal, _Alloc>::swap(__hash_table& __u)
1958#if _LIBCPP_STD_VER <= 11
1959    _NOEXCEPT_(__is_nothrow_swappable<hasher>::value&& __is_nothrow_swappable<key_equal>::value &&
1960               (!allocator_traits<__pointer_allocator>::propagate_on_container_swap::value ||
1961                __is_nothrow_swappable<__pointer_allocator>::value) &&
1962               (!__node_traits::propagate_on_container_swap::value || __is_nothrow_swappable<__node_allocator>::value))
1963#else
1964    _NOEXCEPT_(__is_nothrow_swappable<hasher>::value&& __is_nothrow_swappable<key_equal>::value)
1965#endif
1966{
1967  _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(
1968      __node_traits::propagate_on_container_swap::value || this->__node_alloc() == __u.__node_alloc(),
1969      "unordered container::swap: Either propagate_on_container_swap "
1970      "must be true or the allocators must compare equal");
1971  {
1972    __node_pointer_pointer __npp = __bucket_list_.release();
1973    __bucket_list_.reset(__u.__bucket_list_.release());
1974    __u.__bucket_list_.reset(__npp);
1975  }
1976  std::swap(__bucket_list_.get_deleter().size(), __u.__bucket_list_.get_deleter().size());
1977  std::__swap_allocator(__bucket_list_.get_deleter().__alloc(), __u.__bucket_list_.get_deleter().__alloc());
1978  std::__swap_allocator(__node_alloc(), __u.__node_alloc());
1979  std::swap(__p1_.first().__next_, __u.__p1_.first().__next_);
1980  __p2_.swap(__u.__p2_);
1981  __p3_.swap(__u.__p3_);
1982  if (size() > 0)
1983    __bucket_list_[std::__constrain_hash(__p1_.first().__next_->__hash(), bucket_count())] = __p1_.first().__ptr();
1984  if (__u.size() > 0)
1985    __u.__bucket_list_[std::__constrain_hash(__u.__p1_.first().__next_->__hash(), __u.bucket_count())] =
1986        __u.__p1_.first().__ptr();
1987}
1988
1989template <class _Tp, class _Hash, class _Equal, class _Alloc>
1990typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::size_type
1991__hash_table<_Tp, _Hash, _Equal, _Alloc>::bucket_size(size_type __n) const {
1992  _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(
1993      __n < bucket_count(), "unordered container::bucket_size(n) called with n >= bucket_count()");
1994  __next_pointer __np = __bucket_list_[__n];
1995  size_type __bc      = bucket_count();
1996  size_type __r       = 0;
1997  if (__np != nullptr) {
1998    for (__np = __np->__next_; __np != nullptr && std::__constrain_hash(__np->__hash(), __bc) == __n;
1999         __np = __np->__next_, (void)++__r)
2000      ;
2001  }
2002  return __r;
2003}
2004
2005template <class _Tp, class _Hash, class _Equal, class _Alloc>
2006inline _LIBCPP_HIDE_FROM_ABI void
2007swap(__hash_table<_Tp, _Hash, _Equal, _Alloc>& __x, __hash_table<_Tp, _Hash, _Equal, _Alloc>& __y)
2008    _NOEXCEPT_(_NOEXCEPT_(__x.swap(__y))) {
2009  __x.swap(__y);
2010}
2011
2012_LIBCPP_END_NAMESPACE_STD
2013
2014_LIBCPP_POP_MACROS
2015
2016#endif // _LIBCPP___HASH_TABLE
2017