libstdc++
bits/hashtable.h
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1 // hashtable.h header -*- C++ -*-
2 
3 // Copyright (C) 2007-2021 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
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22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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24 
25 /** @file bits/hashtable.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{unordered_map, unordered_set}
28  */
29 
30 #ifndef _HASHTABLE_H
31 #define _HASHTABLE_H 1
32 
33 #pragma GCC system_header
34 
35 #include <bits/hashtable_policy.h>
36 #if __cplusplus > 201402L
37 # include <bits/node_handle.h>
38 #endif
39 
40 namespace std _GLIBCXX_VISIBILITY(default)
41 {
42 _GLIBCXX_BEGIN_NAMESPACE_VERSION
43 
44  template<typename _Tp, typename _Hash>
45  using __cache_default
46  = __not_<__and_<// Do not cache for fast hasher.
47  __is_fast_hash<_Hash>,
48  // Mandatory to have erase not throwing.
49  __is_nothrow_invocable<const _Hash&, const _Tp&>>>;
50 
51  /**
52  * Primary class template _Hashtable.
53  *
54  * @ingroup hashtable-detail
55  *
56  * @tparam _Value CopyConstructible type.
57  *
58  * @tparam _Key CopyConstructible type.
59  *
60  * @tparam _Alloc An allocator type
61  * ([lib.allocator.requirements]) whose _Alloc::value_type is
62  * _Value. As a conforming extension, we allow for
63  * _Alloc::value_type != _Value.
64  *
65  * @tparam _ExtractKey Function object that takes an object of type
66  * _Value and returns a value of type _Key.
67  *
68  * @tparam _Equal Function object that takes two objects of type k
69  * and returns a bool-like value that is true if the two objects
70  * are considered equal.
71  *
72  * @tparam _Hash The hash function. A unary function object with
73  * argument type _Key and result type size_t. Return values should
74  * be distributed over the entire range [0, numeric_limits<size_t>:::max()].
75  *
76  * @tparam _RangeHash The range-hashing function (in the terminology of
77  * Tavori and Dreizin). A binary function object whose argument
78  * types and result type are all size_t. Given arguments r and N,
79  * the return value is in the range [0, N).
80  *
81  * @tparam _Unused Not used.
82  *
83  * @tparam _RehashPolicy Policy class with three members, all of
84  * which govern the bucket count. _M_next_bkt(n) returns a bucket
85  * count no smaller than n. _M_bkt_for_elements(n) returns a
86  * bucket count appropriate for an element count of n.
87  * _M_need_rehash(n_bkt, n_elt, n_ins) determines whether, if the
88  * current bucket count is n_bkt and the current element count is
89  * n_elt, we need to increase the bucket count for n_ins insertions.
90  * If so, returns make_pair(true, n), where n is the new bucket count. If
91  * not, returns make_pair(false, <anything>)
92  *
93  * @tparam _Traits Compile-time class with three boolean
94  * std::integral_constant members: __cache_hash_code, __constant_iterators,
95  * __unique_keys.
96  *
97  * Each _Hashtable data structure has:
98  *
99  * - _Bucket[] _M_buckets
100  * - _Hash_node_base _M_before_begin
101  * - size_type _M_bucket_count
102  * - size_type _M_element_count
103  *
104  * with _Bucket being _Hash_node_base* and _Hash_node containing:
105  *
106  * - _Hash_node* _M_next
107  * - Tp _M_value
108  * - size_t _M_hash_code if cache_hash_code is true
109  *
110  * In terms of Standard containers the hashtable is like the aggregation of:
111  *
112  * - std::forward_list<_Node> containing the elements
113  * - std::vector<std::forward_list<_Node>::iterator> representing the buckets
114  *
115  * The non-empty buckets contain the node before the first node in the
116  * bucket. This design makes it possible to implement something like a
117  * std::forward_list::insert_after on container insertion and
118  * std::forward_list::erase_after on container erase
119  * calls. _M_before_begin is equivalent to
120  * std::forward_list::before_begin. Empty buckets contain
121  * nullptr. Note that one of the non-empty buckets contains
122  * &_M_before_begin which is not a dereferenceable node so the
123  * node pointer in a bucket shall never be dereferenced, only its
124  * next node can be.
125  *
126  * Walking through a bucket's nodes requires a check on the hash code to
127  * see if each node is still in the bucket. Such a design assumes a
128  * quite efficient hash functor and is one of the reasons it is
129  * highly advisable to set __cache_hash_code to true.
130  *
131  * The container iterators are simply built from nodes. This way
132  * incrementing the iterator is perfectly efficient independent of
133  * how many empty buckets there are in the container.
134  *
135  * On insert we compute the element's hash code and use it to find the
136  * bucket index. If the element must be inserted in an empty bucket
137  * we add it at the beginning of the singly linked list and make the
138  * bucket point to _M_before_begin. The bucket that used to point to
139  * _M_before_begin, if any, is updated to point to its new before
140  * begin node.
141  *
142  * On erase, the simple iterator design requires using the hash
143  * functor to get the index of the bucket to update. For this
144  * reason, when __cache_hash_code is set to false the hash functor must
145  * not throw and this is enforced by a static assertion.
146  *
147  * Functionality is implemented by decomposition into base classes,
148  * where the derived _Hashtable class is used in _Map_base,
149  * _Insert, _Rehash_base, and _Equality base classes to access the
150  * "this" pointer. _Hashtable_base is used in the base classes as a
151  * non-recursive, fully-completed-type so that detailed nested type
152  * information, such as iterator type and node type, can be
153  * used. This is similar to the "Curiously Recurring Template
154  * Pattern" (CRTP) technique, but uses a reconstructed, not
155  * explicitly passed, template pattern.
156  *
157  * Base class templates are:
158  * - __detail::_Hashtable_base
159  * - __detail::_Map_base
160  * - __detail::_Insert
161  * - __detail::_Rehash_base
162  * - __detail::_Equality
163  */
164  template<typename _Key, typename _Value, typename _Alloc,
165  typename _ExtractKey, typename _Equal,
166  typename _Hash, typename _RangeHash, typename _Unused,
167  typename _RehashPolicy, typename _Traits>
169  : public __detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal,
170  _Hash, _RangeHash, _Unused, _Traits>,
171  public __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
172  _Hash, _RangeHash, _Unused,
173  _RehashPolicy, _Traits>,
174  public __detail::_Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
175  _Hash, _RangeHash, _Unused,
176  _RehashPolicy, _Traits>,
177  public __detail::_Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
178  _Hash, _RangeHash, _Unused,
179  _RehashPolicy, _Traits>,
180  public __detail::_Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
181  _Hash, _RangeHash, _Unused,
182  _RehashPolicy, _Traits>,
184  __alloc_rebind<_Alloc,
185  __detail::_Hash_node<_Value,
186  _Traits::__hash_cached::value>>>
187  {
188  static_assert(is_same<typename remove_cv<_Value>::type, _Value>::value,
189  "unordered container must have a non-const, non-volatile value_type");
190 #if __cplusplus > 201703L || defined __STRICT_ANSI__
192  "unordered container must have the same value_type as its allocator");
193 #endif
194 
195  using __traits_type = _Traits;
196  using __hash_cached = typename __traits_type::__hash_cached;
197  using __constant_iterators = typename __traits_type::__constant_iterators;
199  using __node_alloc_type = __alloc_rebind<_Alloc, __node_type>;
200 
202 
203  using __node_value_type =
204  __detail::_Hash_node_value<_Value, __hash_cached::value>;
205  using __node_ptr = typename __hashtable_alloc::__node_ptr;
206  using __value_alloc_traits =
207  typename __hashtable_alloc::__value_alloc_traits;
208  using __node_alloc_traits =
210  using __node_base = typename __hashtable_alloc::__node_base;
211  using __node_base_ptr = typename __hashtable_alloc::__node_base_ptr;
212  using __buckets_ptr = typename __hashtable_alloc::__buckets_ptr;
213 
214  using __insert_base = __detail::_Insert<_Key, _Value, _Alloc, _ExtractKey,
215  _Equal, _Hash,
216  _RangeHash, _Unused,
217  _RehashPolicy, _Traits>;
218 
219  public:
220  typedef _Key key_type;
221  typedef _Value value_type;
222  typedef _Alloc allocator_type;
223  typedef _Equal key_equal;
224 
225  // mapped_type, if present, comes from _Map_base.
226  // hasher, if present, comes from _Hash_code_base/_Hashtable_base.
227  typedef typename __value_alloc_traits::pointer pointer;
228  typedef typename __value_alloc_traits::const_pointer const_pointer;
229  typedef value_type& reference;
230  typedef const value_type& const_reference;
231 
232  using iterator = typename __insert_base::iterator;
233 
234  using const_iterator = typename __insert_base::const_iterator;
235 
236  using local_iterator = __detail::_Local_iterator<key_type, _Value,
237  _ExtractKey, _Hash, _RangeHash, _Unused,
238  __constant_iterators::value,
239  __hash_cached::value>;
240 
242  key_type, _Value,
243  _ExtractKey, _Hash, _RangeHash, _Unused,
244  __constant_iterators::value, __hash_cached::value>;
245 
246  private:
247  using __rehash_type = _RehashPolicy;
248  using __rehash_state = typename __rehash_type::_State;
249 
250  using __unique_keys = typename __traits_type::__unique_keys;
251 
253  _Hashtable_base<_Key, _Value, _ExtractKey,
254  _Equal, _Hash, _RangeHash, _Unused, _Traits>;
255 
256  using __hash_code_base = typename __hashtable_base::__hash_code_base;
257  using __hash_code = typename __hashtable_base::__hash_code;
258  using __ireturn_type = typename __insert_base::__ireturn_type;
259 
260  using __map_base = __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey,
261  _Equal, _Hash, _RangeHash, _Unused,
262  _RehashPolicy, _Traits>;
263 
264  using __rehash_base = __detail::_Rehash_base<_Key, _Value, _Alloc,
265  _ExtractKey, _Equal,
266  _Hash, _RangeHash, _Unused,
267  _RehashPolicy, _Traits>;
268 
269  using __eq_base = __detail::_Equality<_Key, _Value, _Alloc, _ExtractKey,
270  _Equal, _Hash, _RangeHash, _Unused,
271  _RehashPolicy, _Traits>;
272 
273  using __reuse_or_alloc_node_gen_t =
274  __detail::_ReuseOrAllocNode<__node_alloc_type>;
275  using __alloc_node_gen_t =
276  __detail::_AllocNode<__node_alloc_type>;
277 
278  // Simple RAII type for managing a node containing an element
279  struct _Scoped_node
280  {
281  // Take ownership of a node with a constructed element.
282  _Scoped_node(__node_ptr __n, __hashtable_alloc* __h)
283  : _M_h(__h), _M_node(__n) { }
284 
285  // Allocate a node and construct an element within it.
286  template<typename... _Args>
287  _Scoped_node(__hashtable_alloc* __h, _Args&&... __args)
288  : _M_h(__h),
289  _M_node(__h->_M_allocate_node(std::forward<_Args>(__args)...))
290  { }
291 
292  // Destroy element and deallocate node.
293  ~_Scoped_node() { if (_M_node) _M_h->_M_deallocate_node(_M_node); };
294 
295  _Scoped_node(const _Scoped_node&) = delete;
296  _Scoped_node& operator=(const _Scoped_node&) = delete;
297 
298  __hashtable_alloc* _M_h;
299  __node_ptr _M_node;
300  };
301 
302  template<typename _Ht>
303  static constexpr
305  const value_type&, value_type&&>::type
306  __fwd_value_for(value_type& __val) noexcept
307  { return std::move(__val); }
308 
309  // Compile-time diagnostics.
310 
311  // _Hash_code_base has everything protected, so use this derived type to
312  // access it.
313  struct __hash_code_base_access : __hash_code_base
314  { using __hash_code_base::_M_bucket_index; };
315 
316  // Getting a bucket index from a node shall not throw because it is used
317  // in methods (erase, swap...) that shall not throw.
318  static_assert(noexcept(declval<const __hash_code_base_access&>()
319  ._M_bucket_index(declval<const __node_value_type&>(),
320  (std::size_t)0)),
321  "Cache the hash code or qualify your functors involved"
322  " in hash code and bucket index computation with noexcept");
323 
324  // To get bucket index we need _RangeHash not to throw.
326  "Functor used to map hash code to bucket index"
327  " must be nothrow default constructible");
328  static_assert(noexcept(
329  std::declval<const _RangeHash&>()((std::size_t)0, (std::size_t)0)),
330  "Functor used to map hash code to bucket index must be"
331  " noexcept");
332 
333  // To compute bucket index we also need _ExtratKey not to throw.
335  "_ExtractKey must be nothrow default constructible");
336  static_assert(noexcept(
337  std::declval<const _ExtractKey&>()(std::declval<_Value>())),
338  "_ExtractKey functor must be noexcept invocable");
339 
340  template<typename _Keya, typename _Valuea, typename _Alloca,
341  typename _ExtractKeya, typename _Equala,
342  typename _Hasha, typename _RangeHasha, typename _Unuseda,
343  typename _RehashPolicya, typename _Traitsa,
344  bool _Unique_keysa>
345  friend struct __detail::_Map_base;
346 
347  template<typename _Keya, typename _Valuea, typename _Alloca,
348  typename _ExtractKeya, typename _Equala,
349  typename _Hasha, typename _RangeHasha, typename _Unuseda,
350  typename _RehashPolicya, typename _Traitsa>
351  friend struct __detail::_Insert_base;
352 
353  template<typename _Keya, typename _Valuea, typename _Alloca,
354  typename _ExtractKeya, typename _Equala,
355  typename _Hasha, typename _RangeHasha, typename _Unuseda,
356  typename _RehashPolicya, typename _Traitsa,
357  bool _Constant_iteratorsa>
358  friend struct __detail::_Insert;
359 
360  template<typename _Keya, typename _Valuea, typename _Alloca,
361  typename _ExtractKeya, typename _Equala,
362  typename _Hasha, typename _RangeHasha, typename _Unuseda,
363  typename _RehashPolicya, typename _Traitsa,
364  bool _Unique_keysa>
365  friend struct __detail::_Equality;
366 
367  public:
368  using size_type = typename __hashtable_base::size_type;
369  using difference_type = typename __hashtable_base::difference_type;
370 
371 #if __cplusplus > 201402L
374 #endif
375 
376  private:
377  __buckets_ptr _M_buckets = &_M_single_bucket;
378  size_type _M_bucket_count = 1;
379  __node_base _M_before_begin;
380  size_type _M_element_count = 0;
381  _RehashPolicy _M_rehash_policy;
382 
383  // A single bucket used when only need for 1 bucket. Especially
384  // interesting in move semantic to leave hashtable with only 1 bucket
385  // which is not allocated so that we can have those operations noexcept
386  // qualified.
387  // Note that we can't leave hashtable with 0 bucket without adding
388  // numerous checks in the code to avoid 0 modulus.
389  __node_base_ptr _M_single_bucket = nullptr;
390 
391  void
392  _M_update_bbegin()
393  {
394  if (_M_begin())
395  _M_buckets[_M_bucket_index(*_M_begin())] = &_M_before_begin;
396  }
397 
398  void
399  _M_update_bbegin(__node_ptr __n)
400  {
401  _M_before_begin._M_nxt = __n;
402  _M_update_bbegin();
403  }
404 
405  bool
406  _M_uses_single_bucket(__buckets_ptr __bkts) const
407  { return __builtin_expect(__bkts == &_M_single_bucket, false); }
408 
409  bool
410  _M_uses_single_bucket() const
411  { return _M_uses_single_bucket(_M_buckets); }
412 
414  _M_base_alloc() { return *this; }
415 
416  __buckets_ptr
417  _M_allocate_buckets(size_type __bkt_count)
418  {
419  if (__builtin_expect(__bkt_count == 1, false))
420  {
421  _M_single_bucket = nullptr;
422  return &_M_single_bucket;
423  }
424 
425  return __hashtable_alloc::_M_allocate_buckets(__bkt_count);
426  }
427 
428  void
429  _M_deallocate_buckets(__buckets_ptr __bkts, size_type __bkt_count)
430  {
431  if (_M_uses_single_bucket(__bkts))
432  return;
433 
434  __hashtable_alloc::_M_deallocate_buckets(__bkts, __bkt_count);
435  }
436 
437  void
438  _M_deallocate_buckets()
439  { _M_deallocate_buckets(_M_buckets, _M_bucket_count); }
440 
441  // Gets bucket begin, deals with the fact that non-empty buckets contain
442  // their before begin node.
443  __node_ptr
444  _M_bucket_begin(size_type __bkt) const;
445 
446  __node_ptr
447  _M_begin() const
448  { return static_cast<__node_ptr>(_M_before_begin._M_nxt); }
449 
450  // Assign *this using another _Hashtable instance. Whether elements
451  // are copied or moved depends on the _Ht reference.
452  template<typename _Ht>
453  void
454  _M_assign_elements(_Ht&&);
455 
456  template<typename _Ht, typename _NodeGenerator>
457  void
458  _M_assign(_Ht&&, const _NodeGenerator&);
459 
460  void
461  _M_move_assign(_Hashtable&&, true_type);
462 
463  void
464  _M_move_assign(_Hashtable&&, false_type);
465 
466  void
467  _M_reset() noexcept;
468 
469  _Hashtable(const _Hash& __h, const _Equal& __eq,
470  const allocator_type& __a)
471  : __hashtable_base(__h, __eq),
472  __hashtable_alloc(__node_alloc_type(__a))
473  { }
474 
475  template<bool _No_realloc = true>
476  static constexpr bool
477  _S_nothrow_move()
478  {
479 #if __cplusplus <= 201402L
480  return __and_<__bool_constant<_No_realloc>,
483 #else
484  if constexpr (_No_realloc)
485  if constexpr (is_nothrow_copy_constructible<_Hash>())
487  return false;
488 #endif
489  }
490 
491  _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
492  true_type /* alloc always equal */)
493  noexcept(_S_nothrow_move());
494 
495  _Hashtable(_Hashtable&&, __node_alloc_type&&,
496  false_type /* alloc always equal */);
497 
498  template<typename _InputIterator>
499  _Hashtable(_InputIterator __first, _InputIterator __last,
500  size_type __bkt_count_hint,
501  const _Hash&, const _Equal&, const allocator_type&,
502  true_type __uks);
503 
504  template<typename _InputIterator>
505  _Hashtable(_InputIterator __first, _InputIterator __last,
506  size_type __bkt_count_hint,
507  const _Hash&, const _Equal&, const allocator_type&,
508  false_type __uks);
509 
510  public:
511  // Constructor, destructor, assignment, swap
512  _Hashtable() = default;
513 
514  _Hashtable(const _Hashtable&);
515 
516  _Hashtable(const _Hashtable&, const allocator_type&);
517 
518  explicit
519  _Hashtable(size_type __bkt_count_hint,
520  const _Hash& __hf = _Hash(),
521  const key_equal& __eql = key_equal(),
522  const allocator_type& __a = allocator_type());
523 
524  // Use delegating constructors.
525  _Hashtable(_Hashtable&& __ht)
526  noexcept(_S_nothrow_move())
527  : _Hashtable(std::move(__ht), std::move(__ht._M_node_allocator()),
528  true_type{})
529  { }
530 
531  _Hashtable(_Hashtable&& __ht, const allocator_type& __a)
532  noexcept(_S_nothrow_move<__node_alloc_traits::_S_always_equal()>())
533  : _Hashtable(std::move(__ht), __node_alloc_type(__a),
534  typename __node_alloc_traits::is_always_equal{})
535  { }
536 
537  explicit
538  _Hashtable(const allocator_type& __a)
539  : __hashtable_alloc(__node_alloc_type(__a))
540  { }
541 
542  template<typename _InputIterator>
543  _Hashtable(_InputIterator __f, _InputIterator __l,
544  size_type __bkt_count_hint = 0,
545  const _Hash& __hf = _Hash(),
546  const key_equal& __eql = key_equal(),
547  const allocator_type& __a = allocator_type())
548  : _Hashtable(__f, __l, __bkt_count_hint, __hf, __eql, __a,
549  __unique_keys{})
550  { }
551 
553  size_type __bkt_count_hint = 0,
554  const _Hash& __hf = _Hash(),
555  const key_equal& __eql = key_equal(),
556  const allocator_type& __a = allocator_type())
557  : _Hashtable(__l.begin(), __l.end(), __bkt_count_hint,
558  __hf, __eql, __a, __unique_keys{})
559  { }
560 
561  _Hashtable&
562  operator=(const _Hashtable& __ht);
563 
564  _Hashtable&
565  operator=(_Hashtable&& __ht)
566  noexcept(__node_alloc_traits::_S_nothrow_move()
569  {
570  constexpr bool __move_storage =
571  __node_alloc_traits::_S_propagate_on_move_assign()
572  || __node_alloc_traits::_S_always_equal();
573  _M_move_assign(std::move(__ht), __bool_constant<__move_storage>());
574  return *this;
575  }
576 
577  _Hashtable&
579  {
580  __reuse_or_alloc_node_gen_t __roan(_M_begin(), *this);
581  _M_before_begin._M_nxt = nullptr;
582  clear();
583 
584  // We consider that all elements of __l are going to be inserted.
585  auto __l_bkt_count = _M_rehash_policy._M_bkt_for_elements(__l.size());
586 
587  // Do not shrink to keep potential user reservation.
588  if (_M_bucket_count < __l_bkt_count)
589  rehash(__l_bkt_count);
590 
591  this->_M_insert_range(__l.begin(), __l.end(), __roan, __unique_keys{});
592  return *this;
593  }
594 
595  ~_Hashtable() noexcept;
596 
597  void
598  swap(_Hashtable&)
599  noexcept(__and_<__is_nothrow_swappable<_Hash>,
600  __is_nothrow_swappable<_Equal>>::value);
601 
602  // Basic container operations
603  iterator
604  begin() noexcept
605  { return iterator(_M_begin()); }
606 
607  const_iterator
608  begin() const noexcept
609  { return const_iterator(_M_begin()); }
610 
611  iterator
612  end() noexcept
613  { return iterator(nullptr); }
614 
615  const_iterator
616  end() const noexcept
617  { return const_iterator(nullptr); }
618 
619  const_iterator
620  cbegin() const noexcept
621  { return const_iterator(_M_begin()); }
622 
623  const_iterator
624  cend() const noexcept
625  { return const_iterator(nullptr); }
626 
627  size_type
628  size() const noexcept
629  { return _M_element_count; }
630 
631  _GLIBCXX_NODISCARD bool
632  empty() const noexcept
633  { return size() == 0; }
634 
635  allocator_type
636  get_allocator() const noexcept
637  { return allocator_type(this->_M_node_allocator()); }
638 
639  size_type
640  max_size() const noexcept
641  { return __node_alloc_traits::max_size(this->_M_node_allocator()); }
642 
643  // Observers
644  key_equal
645  key_eq() const
646  { return this->_M_eq(); }
647 
648  // hash_function, if present, comes from _Hash_code_base.
649 
650  // Bucket operations
651  size_type
652  bucket_count() const noexcept
653  { return _M_bucket_count; }
654 
655  size_type
656  max_bucket_count() const noexcept
657  { return max_size(); }
658 
659  size_type
660  bucket_size(size_type __bkt) const
661  { return std::distance(begin(__bkt), end(__bkt)); }
662 
663  size_type
664  bucket(const key_type& __k) const
665  { return _M_bucket_index(this->_M_hash_code(__k)); }
666 
668  begin(size_type __bkt)
669  {
670  return local_iterator(*this, _M_bucket_begin(__bkt),
671  __bkt, _M_bucket_count);
672  }
673 
675  end(size_type __bkt)
676  { return local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
677 
679  begin(size_type __bkt) const
680  {
681  return const_local_iterator(*this, _M_bucket_begin(__bkt),
682  __bkt, _M_bucket_count);
683  }
684 
686  end(size_type __bkt) const
687  { return const_local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
688 
689  // DR 691.
691  cbegin(size_type __bkt) const
692  {
693  return const_local_iterator(*this, _M_bucket_begin(__bkt),
694  __bkt, _M_bucket_count);
695  }
696 
698  cend(size_type __bkt) const
699  { return const_local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
700 
701  float
702  load_factor() const noexcept
703  {
704  return static_cast<float>(size()) / static_cast<float>(bucket_count());
705  }
706 
707  // max_load_factor, if present, comes from _Rehash_base.
708 
709  // Generalization of max_load_factor. Extension, not found in
710  // TR1. Only useful if _RehashPolicy is something other than
711  // the default.
712  const _RehashPolicy&
713  __rehash_policy() const
714  { return _M_rehash_policy; }
715 
716  void
717  __rehash_policy(const _RehashPolicy& __pol)
718  { _M_rehash_policy = __pol; }
719 
720  // Lookup.
721  iterator
722  find(const key_type& __k);
723 
724  const_iterator
725  find(const key_type& __k) const;
726 
727  size_type
728  count(const key_type& __k) const;
729 
731  equal_range(const key_type& __k);
732 
734  equal_range(const key_type& __k) const;
735 
736 #if __cplusplus >= 202002L
737 #define __cpp_lib_generic_unordered_lookup 201811L
738 
739  template<typename _Kt,
740  typename = __has_is_transparent_t<_Hash, _Kt>,
741  typename = __has_is_transparent_t<_Equal, _Kt>>
742  iterator
743  _M_find_tr(const _Kt& __k);
744 
745  template<typename _Kt,
746  typename = __has_is_transparent_t<_Hash, _Kt>,
747  typename = __has_is_transparent_t<_Equal, _Kt>>
748  const_iterator
749  _M_find_tr(const _Kt& __k) const;
750 
751  template<typename _Kt,
752  typename = __has_is_transparent_t<_Hash, _Kt>,
753  typename = __has_is_transparent_t<_Equal, _Kt>>
754  size_type
755  _M_count_tr(const _Kt& __k) const;
756 
757  template<typename _Kt,
758  typename = __has_is_transparent_t<_Hash, _Kt>,
759  typename = __has_is_transparent_t<_Equal, _Kt>>
761  _M_equal_range_tr(const _Kt& __k);
762 
763  template<typename _Kt,
764  typename = __has_is_transparent_t<_Hash, _Kt>,
765  typename = __has_is_transparent_t<_Equal, _Kt>>
767  _M_equal_range_tr(const _Kt& __k) const;
768 #endif // C++20
769 
770  private:
771  // Bucket index computation helpers.
772  size_type
773  _M_bucket_index(const __node_value_type& __n) const noexcept
774  { return __hash_code_base::_M_bucket_index(__n, _M_bucket_count); }
775 
776  size_type
777  _M_bucket_index(__hash_code __c) const
778  { return __hash_code_base::_M_bucket_index(__c, _M_bucket_count); }
779 
780  // Find and insert helper functions and types
781  // Find the node before the one matching the criteria.
782  __node_base_ptr
783  _M_find_before_node(size_type, const key_type&, __hash_code) const;
784 
785  template<typename _Kt>
786  __node_base_ptr
787  _M_find_before_node_tr(size_type, const _Kt&, __hash_code) const;
788 
789  __node_ptr
790  _M_find_node(size_type __bkt, const key_type& __key,
791  __hash_code __c) const
792  {
793  __node_base_ptr __before_n = _M_find_before_node(__bkt, __key, __c);
794  if (__before_n)
795  return static_cast<__node_ptr>(__before_n->_M_nxt);
796  return nullptr;
797  }
798 
799  template<typename _Kt>
800  __node_ptr
801  _M_find_node_tr(size_type __bkt, const _Kt& __key,
802  __hash_code __c) const
803  {
804  auto __before_n = _M_find_before_node_tr(__bkt, __key, __c);
805  if (__before_n)
806  return static_cast<__node_ptr>(__before_n->_M_nxt);
807  return nullptr;
808  }
809 
810  // Insert a node at the beginning of a bucket.
811  void
812  _M_insert_bucket_begin(size_type, __node_ptr);
813 
814  // Remove the bucket first node
815  void
816  _M_remove_bucket_begin(size_type __bkt, __node_ptr __next_n,
817  size_type __next_bkt);
818 
819  // Get the node before __n in the bucket __bkt
820  __node_base_ptr
821  _M_get_previous_node(size_type __bkt, __node_ptr __n);
822 
823  // Insert node __n with hash code __code, in bucket __bkt if no
824  // rehash (assumes no element with same key already present).
825  // Takes ownership of __n if insertion succeeds, throws otherwise.
826  iterator
827  _M_insert_unique_node(size_type __bkt, __hash_code,
828  __node_ptr __n, size_type __n_elt = 1);
829 
830  // Insert node __n with key __k and hash code __code.
831  // Takes ownership of __n if insertion succeeds, throws otherwise.
832  iterator
833  _M_insert_multi_node(__node_ptr __hint,
834  __hash_code __code, __node_ptr __n);
835 
836  template<typename... _Args>
838  _M_emplace(true_type __uks, _Args&&... __args);
839 
840  template<typename... _Args>
841  iterator
842  _M_emplace(false_type __uks, _Args&&... __args)
843  { return _M_emplace(cend(), __uks, std::forward<_Args>(__args)...); }
844 
845  // Emplace with hint, useless when keys are unique.
846  template<typename... _Args>
847  iterator
848  _M_emplace(const_iterator, true_type __uks, _Args&&... __args)
849  { return _M_emplace(__uks, std::forward<_Args>(__args)...).first; }
850 
851  template<typename... _Args>
852  iterator
853  _M_emplace(const_iterator, false_type __uks, _Args&&... __args);
854 
855  template<typename _Arg, typename _NodeGenerator>
857  _M_insert(_Arg&&, const _NodeGenerator&, true_type __uks);
858 
859  template<typename _Arg, typename _NodeGenerator>
860  iterator
861  _M_insert(_Arg&& __arg, const _NodeGenerator& __node_gen,
862  false_type __uks)
863  {
864  return _M_insert(cend(), std::forward<_Arg>(__arg), __node_gen,
865  __uks);
866  }
867 
868  // Insert with hint, not used when keys are unique.
869  template<typename _Arg, typename _NodeGenerator>
870  iterator
871  _M_insert(const_iterator, _Arg&& __arg,
872  const _NodeGenerator& __node_gen, true_type __uks)
873  {
874  return
875  _M_insert(std::forward<_Arg>(__arg), __node_gen, __uks).first;
876  }
877 
878  // Insert with hint when keys are not unique.
879  template<typename _Arg, typename _NodeGenerator>
880  iterator
881  _M_insert(const_iterator, _Arg&&,
882  const _NodeGenerator&, false_type __uks);
883 
884  size_type
885  _M_erase(true_type __uks, const key_type&);
886 
887  size_type
888  _M_erase(false_type __uks, const key_type&);
889 
890  iterator
891  _M_erase(size_type __bkt, __node_base_ptr __prev_n, __node_ptr __n);
892 
893  public:
894  // Emplace
895  template<typename... _Args>
896  __ireturn_type
897  emplace(_Args&&... __args)
898  { return _M_emplace(__unique_keys{}, std::forward<_Args>(__args)...); }
899 
900  template<typename... _Args>
901  iterator
902  emplace_hint(const_iterator __hint, _Args&&... __args)
903  {
904  return _M_emplace(__hint, __unique_keys{},
905  std::forward<_Args>(__args)...);
906  }
907 
908  // Insert member functions via inheritance.
909 
910  // Erase
911  iterator
912  erase(const_iterator);
913 
914  // LWG 2059.
915  iterator
916  erase(iterator __it)
917  { return erase(const_iterator(__it)); }
918 
919  size_type
920  erase(const key_type& __k)
921  { return _M_erase(__unique_keys{}, __k); }
922 
923  iterator
924  erase(const_iterator, const_iterator);
925 
926  void
927  clear() noexcept;
928 
929  // Set number of buckets keeping it appropriate for container's number
930  // of elements.
931  void rehash(size_type __bkt_count);
932 
933  // DR 1189.
934  // reserve, if present, comes from _Rehash_base.
935 
936 #if __cplusplus > 201402L
937  /// Re-insert an extracted node into a container with unique keys.
940  {
941  insert_return_type __ret;
942  if (__nh.empty())
943  __ret.position = end();
944  else
945  {
946  __glibcxx_assert(get_allocator() == __nh.get_allocator());
947 
948  const key_type& __k = __nh._M_key();
949  __hash_code __code = this->_M_hash_code(__k);
950  size_type __bkt = _M_bucket_index(__code);
951  if (__node_ptr __n = _M_find_node(__bkt, __k, __code))
952  {
953  __ret.node = std::move(__nh);
954  __ret.position = iterator(__n);
955  __ret.inserted = false;
956  }
957  else
958  {
959  __ret.position
960  = _M_insert_unique_node(__bkt, __code, __nh._M_ptr);
961  __nh._M_ptr = nullptr;
962  __ret.inserted = true;
963  }
964  }
965  return __ret;
966  }
967 
968  /// Re-insert an extracted node into a container with equivalent keys.
969  iterator
970  _M_reinsert_node_multi(const_iterator __hint, node_type&& __nh)
971  {
972  if (__nh.empty())
973  return end();
974 
975  __glibcxx_assert(get_allocator() == __nh.get_allocator());
976 
977  const key_type& __k = __nh._M_key();
978  auto __code = this->_M_hash_code(__k);
979  auto __ret
980  = _M_insert_multi_node(__hint._M_cur, __code, __nh._M_ptr);
981  __nh._M_ptr = nullptr;
982  return __ret;
983  }
984 
985  private:
986  node_type
987  _M_extract_node(size_t __bkt, __node_base_ptr __prev_n)
988  {
989  __node_ptr __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
990  if (__prev_n == _M_buckets[__bkt])
991  _M_remove_bucket_begin(__bkt, __n->_M_next(),
992  __n->_M_nxt ? _M_bucket_index(*__n->_M_next()) : 0);
993  else if (__n->_M_nxt)
994  {
995  size_type __next_bkt = _M_bucket_index(*__n->_M_next());
996  if (__next_bkt != __bkt)
997  _M_buckets[__next_bkt] = __prev_n;
998  }
999 
1000  __prev_n->_M_nxt = __n->_M_nxt;
1001  __n->_M_nxt = nullptr;
1002  --_M_element_count;
1003  return { __n, this->_M_node_allocator() };
1004  }
1005 
1006  public:
1007  // Extract a node.
1008  node_type
1009  extract(const_iterator __pos)
1010  {
1011  size_t __bkt = _M_bucket_index(*__pos._M_cur);
1012  return _M_extract_node(__bkt,
1013  _M_get_previous_node(__bkt, __pos._M_cur));
1014  }
1015 
1016  /// Extract a node.
1017  node_type
1018  extract(const _Key& __k)
1019  {
1020  node_type __nh;
1021  __hash_code __code = this->_M_hash_code(__k);
1022  std::size_t __bkt = _M_bucket_index(__code);
1023  if (__node_base_ptr __prev_node = _M_find_before_node(__bkt, __k, __code))
1024  __nh = _M_extract_node(__bkt, __prev_node);
1025  return __nh;
1026  }
1027 
1028  /// Merge from a compatible container into one with unique keys.
1029  template<typename _Compatible_Hashtable>
1030  void
1031  _M_merge_unique(_Compatible_Hashtable& __src) noexcept
1032  {
1033  static_assert(is_same_v<typename _Compatible_Hashtable::node_type,
1034  node_type>, "Node types are compatible");
1035  __glibcxx_assert(get_allocator() == __src.get_allocator());
1036 
1037  auto __n_elt = __src.size();
1038  for (auto __i = __src.begin(), __end = __src.end(); __i != __end;)
1039  {
1040  auto __pos = __i++;
1041  const key_type& __k = _ExtractKey{}(*__pos);
1042  __hash_code __code = this->_M_hash_code(__k);
1043  size_type __bkt = _M_bucket_index(__code);
1044  if (_M_find_node(__bkt, __k, __code) == nullptr)
1045  {
1046  auto __nh = __src.extract(__pos);
1047  _M_insert_unique_node(__bkt, __code, __nh._M_ptr, __n_elt);
1048  __nh._M_ptr = nullptr;
1049  __n_elt = 1;
1050  }
1051  else if (__n_elt != 1)
1052  --__n_elt;
1053  }
1054  }
1055 
1056  /// Merge from a compatible container into one with equivalent keys.
1057  template<typename _Compatible_Hashtable>
1058  void
1059  _M_merge_multi(_Compatible_Hashtable& __src) noexcept
1060  {
1061  static_assert(is_same_v<typename _Compatible_Hashtable::node_type,
1062  node_type>, "Node types are compatible");
1063  __glibcxx_assert(get_allocator() == __src.get_allocator());
1064 
1065  this->reserve(size() + __src.size());
1066  for (auto __i = __src.begin(), __end = __src.end(); __i != __end;)
1067  _M_reinsert_node_multi(cend(), __src.extract(__i++));
1068  }
1069 #endif // C++17
1070 
1071  private:
1072  // Helper rehash method used when keys are unique.
1073  void _M_rehash_aux(size_type __bkt_count, true_type __uks);
1074 
1075  // Helper rehash method used when keys can be non-unique.
1076  void _M_rehash_aux(size_type __bkt_count, false_type __uks);
1077 
1078  // Unconditionally change size of bucket array to n, restore
1079  // hash policy state to __state on exception.
1080  void _M_rehash(size_type __bkt_count, const __rehash_state& __state);
1081  };
1082 
1083 
1084  // Definitions of class template _Hashtable's out-of-line member functions.
1085  template<typename _Key, typename _Value, typename _Alloc,
1086  typename _ExtractKey, typename _Equal,
1087  typename _Hash, typename _RangeHash, typename _Unused,
1088  typename _RehashPolicy, typename _Traits>
1089  auto
1090  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1091  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1092  _M_bucket_begin(size_type __bkt) const
1093  -> __node_ptr
1094  {
1095  __node_base_ptr __n = _M_buckets[__bkt];
1096  return __n ? static_cast<__node_ptr>(__n->_M_nxt) : nullptr;
1097  }
1098 
1099  template<typename _Key, typename _Value, typename _Alloc,
1100  typename _ExtractKey, typename _Equal,
1101  typename _Hash, typename _RangeHash, typename _Unused,
1102  typename _RehashPolicy, typename _Traits>
1103  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1104  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1105  _Hashtable(size_type __bkt_count_hint,
1106  const _Hash& __h, const _Equal& __eq, const allocator_type& __a)
1107  : _Hashtable(__h, __eq, __a)
1108  {
1109  auto __bkt_count = _M_rehash_policy._M_next_bkt(__bkt_count_hint);
1110  if (__bkt_count > _M_bucket_count)
1111  {
1112  _M_buckets = _M_allocate_buckets(__bkt_count);
1113  _M_bucket_count = __bkt_count;
1114  }
1115  }
1116 
1117  template<typename _Key, typename _Value, typename _Alloc,
1118  typename _ExtractKey, typename _Equal,
1119  typename _Hash, typename _RangeHash, typename _Unused,
1120  typename _RehashPolicy, typename _Traits>
1121  template<typename _InputIterator>
1122  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1123  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1124  _Hashtable(_InputIterator __f, _InputIterator __l,
1125  size_type __bkt_count_hint,
1126  const _Hash& __h, const _Equal& __eq,
1127  const allocator_type& __a, true_type /* __uks */)
1128  : _Hashtable(__bkt_count_hint, __h, __eq, __a)
1129  {
1130  for (; __f != __l; ++__f)
1131  this->insert(*__f);
1132  }
1133 
1134  template<typename _Key, typename _Value, typename _Alloc,
1135  typename _ExtractKey, typename _Equal,
1136  typename _Hash, typename _RangeHash, typename _Unused,
1137  typename _RehashPolicy, typename _Traits>
1138  template<typename _InputIterator>
1139  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1140  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1141  _Hashtable(_InputIterator __f, _InputIterator __l,
1142  size_type __bkt_count_hint,
1143  const _Hash& __h, const _Equal& __eq,
1144  const allocator_type& __a, false_type /* __uks */)
1145  : _Hashtable(__h, __eq, __a)
1146  {
1147  auto __nb_elems = __detail::__distance_fw(__f, __l);
1148  auto __bkt_count =
1149  _M_rehash_policy._M_next_bkt(
1150  std::max(_M_rehash_policy._M_bkt_for_elements(__nb_elems),
1151  __bkt_count_hint));
1152 
1153  if (__bkt_count > _M_bucket_count)
1154  {
1155  _M_buckets = _M_allocate_buckets(__bkt_count);
1156  _M_bucket_count = __bkt_count;
1157  }
1158 
1159  for (; __f != __l; ++__f)
1160  this->insert(*__f);
1161  }
1162 
1163  template<typename _Key, typename _Value, typename _Alloc,
1164  typename _ExtractKey, typename _Equal,
1165  typename _Hash, typename _RangeHash, typename _Unused,
1166  typename _RehashPolicy, typename _Traits>
1167  auto
1168  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1169  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1170  operator=(const _Hashtable& __ht)
1171  -> _Hashtable&
1172  {
1173  if (&__ht == this)
1174  return *this;
1175 
1176  if (__node_alloc_traits::_S_propagate_on_copy_assign())
1177  {
1178  auto& __this_alloc = this->_M_node_allocator();
1179  auto& __that_alloc = __ht._M_node_allocator();
1180  if (!__node_alloc_traits::_S_always_equal()
1181  && __this_alloc != __that_alloc)
1182  {
1183  // Replacement allocator cannot free existing storage.
1184  this->_M_deallocate_nodes(_M_begin());
1185  _M_before_begin._M_nxt = nullptr;
1186  _M_deallocate_buckets();
1187  _M_buckets = nullptr;
1188  std::__alloc_on_copy(__this_alloc, __that_alloc);
1190  _M_bucket_count = __ht._M_bucket_count;
1191  _M_element_count = __ht._M_element_count;
1192  _M_rehash_policy = __ht._M_rehash_policy;
1193  __alloc_node_gen_t __alloc_node_gen(*this);
1194  __try
1195  {
1196  _M_assign(__ht, __alloc_node_gen);
1197  }
1198  __catch(...)
1199  {
1200  // _M_assign took care of deallocating all memory. Now we
1201  // must make sure this instance remains in a usable state.
1202  _M_reset();
1203  __throw_exception_again;
1204  }
1205  return *this;
1206  }
1207  std::__alloc_on_copy(__this_alloc, __that_alloc);
1208  }
1209 
1210  // Reuse allocated buckets and nodes.
1211  _M_assign_elements(__ht);
1212  return *this;
1213  }
1214 
1215  template<typename _Key, typename _Value, typename _Alloc,
1216  typename _ExtractKey, typename _Equal,
1217  typename _Hash, typename _RangeHash, typename _Unused,
1218  typename _RehashPolicy, typename _Traits>
1219  template<typename _Ht>
1220  void
1221  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1222  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1223  _M_assign_elements(_Ht&& __ht)
1224  {
1225  __buckets_ptr __former_buckets = nullptr;
1226  std::size_t __former_bucket_count = _M_bucket_count;
1227  const __rehash_state& __former_state = _M_rehash_policy._M_state();
1228 
1229  if (_M_bucket_count != __ht._M_bucket_count)
1230  {
1231  __former_buckets = _M_buckets;
1232  _M_buckets = _M_allocate_buckets(__ht._M_bucket_count);
1233  _M_bucket_count = __ht._M_bucket_count;
1234  }
1235  else
1236  __builtin_memset(_M_buckets, 0,
1237  _M_bucket_count * sizeof(__node_base_ptr));
1238 
1239  __try
1240  {
1241  __hashtable_base::operator=(std::forward<_Ht>(__ht));
1242  _M_element_count = __ht._M_element_count;
1243  _M_rehash_policy = __ht._M_rehash_policy;
1244  __reuse_or_alloc_node_gen_t __roan(_M_begin(), *this);
1245  _M_before_begin._M_nxt = nullptr;
1246  _M_assign(std::forward<_Ht>(__ht), __roan);
1247  if (__former_buckets)
1248  _M_deallocate_buckets(__former_buckets, __former_bucket_count);
1249  }
1250  __catch(...)
1251  {
1252  if (__former_buckets)
1253  {
1254  // Restore previous buckets.
1255  _M_deallocate_buckets();
1256  _M_rehash_policy._M_reset(__former_state);
1257  _M_buckets = __former_buckets;
1258  _M_bucket_count = __former_bucket_count;
1259  }
1260  __builtin_memset(_M_buckets, 0,
1261  _M_bucket_count * sizeof(__node_base_ptr));
1262  __throw_exception_again;
1263  }
1264  }
1265 
1266  template<typename _Key, typename _Value, typename _Alloc,
1267  typename _ExtractKey, typename _Equal,
1268  typename _Hash, typename _RangeHash, typename _Unused,
1269  typename _RehashPolicy, typename _Traits>
1270  template<typename _Ht, typename _NodeGenerator>
1271  void
1272  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1273  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1274  _M_assign(_Ht&& __ht, const _NodeGenerator& __node_gen)
1275  {
1276  __buckets_ptr __buckets = nullptr;
1277  if (!_M_buckets)
1278  _M_buckets = __buckets = _M_allocate_buckets(_M_bucket_count);
1279 
1280  __try
1281  {
1282  if (!__ht._M_before_begin._M_nxt)
1283  return;
1284 
1285  // First deal with the special first node pointed to by
1286  // _M_before_begin.
1287  __node_ptr __ht_n = __ht._M_begin();
1288  __node_ptr __this_n
1289  = __node_gen(__fwd_value_for<_Ht>(__ht_n->_M_v()));
1290  this->_M_copy_code(*__this_n, *__ht_n);
1291  _M_update_bbegin(__this_n);
1292 
1293  // Then deal with other nodes.
1294  __node_ptr __prev_n = __this_n;
1295  for (__ht_n = __ht_n->_M_next(); __ht_n; __ht_n = __ht_n->_M_next())
1296  {
1297  __this_n = __node_gen(__fwd_value_for<_Ht>(__ht_n->_M_v()));
1298  __prev_n->_M_nxt = __this_n;
1299  this->_M_copy_code(*__this_n, *__ht_n);
1300  size_type __bkt = _M_bucket_index(*__this_n);
1301  if (!_M_buckets[__bkt])
1302  _M_buckets[__bkt] = __prev_n;
1303  __prev_n = __this_n;
1304  }
1305  }
1306  __catch(...)
1307  {
1308  clear();
1309  if (__buckets)
1310  _M_deallocate_buckets();
1311  __throw_exception_again;
1312  }
1313  }
1314 
1315  template<typename _Key, typename _Value, typename _Alloc,
1316  typename _ExtractKey, typename _Equal,
1317  typename _Hash, typename _RangeHash, typename _Unused,
1318  typename _RehashPolicy, typename _Traits>
1319  void
1320  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1321  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1322  _M_reset() noexcept
1323  {
1324  _M_rehash_policy._M_reset();
1325  _M_bucket_count = 1;
1326  _M_single_bucket = nullptr;
1327  _M_buckets = &_M_single_bucket;
1328  _M_before_begin._M_nxt = nullptr;
1329  _M_element_count = 0;
1330  }
1331 
1332  template<typename _Key, typename _Value, typename _Alloc,
1333  typename _ExtractKey, typename _Equal,
1334  typename _Hash, typename _RangeHash, typename _Unused,
1335  typename _RehashPolicy, typename _Traits>
1336  void
1337  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1338  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1339  _M_move_assign(_Hashtable&& __ht, true_type)
1340  {
1341  if (__builtin_expect(std::__addressof(__ht) == this, false))
1342  return;
1343 
1344  this->_M_deallocate_nodes(_M_begin());
1345  _M_deallocate_buckets();
1347  _M_rehash_policy = __ht._M_rehash_policy;
1348  if (!__ht._M_uses_single_bucket())
1349  _M_buckets = __ht._M_buckets;
1350  else
1351  {
1352  _M_buckets = &_M_single_bucket;
1353  _M_single_bucket = __ht._M_single_bucket;
1354  }
1355 
1356  _M_bucket_count = __ht._M_bucket_count;
1357  _M_before_begin._M_nxt = __ht._M_before_begin._M_nxt;
1358  _M_element_count = __ht._M_element_count;
1359  std::__alloc_on_move(this->_M_node_allocator(), __ht._M_node_allocator());
1360 
1361  // Fix bucket containing the _M_before_begin pointer that can't be moved.
1362  _M_update_bbegin();
1363  __ht._M_reset();
1364  }
1365 
1366  template<typename _Key, typename _Value, typename _Alloc,
1367  typename _ExtractKey, typename _Equal,
1368  typename _Hash, typename _RangeHash, typename _Unused,
1369  typename _RehashPolicy, typename _Traits>
1370  void
1371  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1372  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1373  _M_move_assign(_Hashtable&& __ht, false_type)
1374  {
1375  if (__ht._M_node_allocator() == this->_M_node_allocator())
1376  _M_move_assign(std::move(__ht), true_type{});
1377  else
1378  {
1379  // Can't move memory, move elements then.
1380  _M_assign_elements(std::move(__ht));
1381  __ht.clear();
1382  }
1383  }
1384 
1385  template<typename _Key, typename _Value, typename _Alloc,
1386  typename _ExtractKey, typename _Equal,
1387  typename _Hash, typename _RangeHash, typename _Unused,
1388  typename _RehashPolicy, typename _Traits>
1389  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1390  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1391  _Hashtable(const _Hashtable& __ht)
1392  : __hashtable_base(__ht),
1393  __map_base(__ht),
1394  __rehash_base(__ht),
1395  __hashtable_alloc(
1396  __node_alloc_traits::_S_select_on_copy(__ht._M_node_allocator())),
1397  _M_buckets(nullptr),
1398  _M_bucket_count(__ht._M_bucket_count),
1399  _M_element_count(__ht._M_element_count),
1400  _M_rehash_policy(__ht._M_rehash_policy)
1401  {
1402  __alloc_node_gen_t __alloc_node_gen(*this);
1403  _M_assign(__ht, __alloc_node_gen);
1404  }
1405 
1406  template<typename _Key, typename _Value, typename _Alloc,
1407  typename _ExtractKey, typename _Equal,
1408  typename _Hash, typename _RangeHash, typename _Unused,
1409  typename _RehashPolicy, typename _Traits>
1410  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1411  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1412  _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
1413  true_type /* alloc always equal */)
1414  noexcept(_S_nothrow_move())
1415  : __hashtable_base(__ht),
1416  __map_base(__ht),
1417  __rehash_base(__ht),
1418  __hashtable_alloc(std::move(__a)),
1419  _M_buckets(__ht._M_buckets),
1420  _M_bucket_count(__ht._M_bucket_count),
1421  _M_before_begin(__ht._M_before_begin._M_nxt),
1422  _M_element_count(__ht._M_element_count),
1423  _M_rehash_policy(__ht._M_rehash_policy)
1424  {
1425  // Update buckets if __ht is using its single bucket.
1426  if (__ht._M_uses_single_bucket())
1427  {
1428  _M_buckets = &_M_single_bucket;
1429  _M_single_bucket = __ht._M_single_bucket;
1430  }
1431 
1432  // Fix bucket containing the _M_before_begin pointer that can't be moved.
1433  _M_update_bbegin();
1434 
1435  __ht._M_reset();
1436  }
1437 
1438  template<typename _Key, typename _Value, typename _Alloc,
1439  typename _ExtractKey, typename _Equal,
1440  typename _Hash, typename _RangeHash, typename _Unused,
1441  typename _RehashPolicy, typename _Traits>
1442  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1443  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1444  _Hashtable(const _Hashtable& __ht, const allocator_type& __a)
1445  : __hashtable_base(__ht),
1446  __map_base(__ht),
1447  __rehash_base(__ht),
1448  __hashtable_alloc(__node_alloc_type(__a)),
1449  _M_buckets(),
1450  _M_bucket_count(__ht._M_bucket_count),
1451  _M_element_count(__ht._M_element_count),
1452  _M_rehash_policy(__ht._M_rehash_policy)
1453  {
1454  __alloc_node_gen_t __alloc_node_gen(*this);
1455  _M_assign(__ht, __alloc_node_gen);
1456  }
1457 
1458  template<typename _Key, typename _Value, typename _Alloc,
1459  typename _ExtractKey, typename _Equal,
1460  typename _Hash, typename _RangeHash, typename _Unused,
1461  typename _RehashPolicy, typename _Traits>
1462  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1463  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1464  _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
1465  false_type /* alloc always equal */)
1466  : __hashtable_base(__ht),
1467  __map_base(__ht),
1468  __rehash_base(__ht),
1469  __hashtable_alloc(std::move(__a)),
1470  _M_buckets(nullptr),
1471  _M_bucket_count(__ht._M_bucket_count),
1472  _M_element_count(__ht._M_element_count),
1473  _M_rehash_policy(__ht._M_rehash_policy)
1474  {
1475  if (__ht._M_node_allocator() == this->_M_node_allocator())
1476  {
1477  if (__ht._M_uses_single_bucket())
1478  {
1479  _M_buckets = &_M_single_bucket;
1480  _M_single_bucket = __ht._M_single_bucket;
1481  }
1482  else
1483  _M_buckets = __ht._M_buckets;
1484 
1485  // Fix bucket containing the _M_before_begin pointer that can't be
1486  // moved.
1487  _M_update_bbegin(__ht._M_begin());
1488 
1489  __ht._M_reset();
1490  }
1491  else
1492  {
1493  __alloc_node_gen_t __alloc_gen(*this);
1494 
1495  using _Fwd_Ht = typename
1496  conditional<__move_if_noexcept_cond<value_type>::value,
1497  const _Hashtable&, _Hashtable&&>::type;
1498  _M_assign(std::forward<_Fwd_Ht>(__ht), __alloc_gen);
1499  __ht.clear();
1500  }
1501  }
1502 
1503  template<typename _Key, typename _Value, typename _Alloc,
1504  typename _ExtractKey, typename _Equal,
1505  typename _Hash, typename _RangeHash, typename _Unused,
1506  typename _RehashPolicy, typename _Traits>
1507  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1508  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1509  ~_Hashtable() noexcept
1510  {
1511  clear();
1512  _M_deallocate_buckets();
1513  }
1514 
1515  template<typename _Key, typename _Value, typename _Alloc,
1516  typename _ExtractKey, typename _Equal,
1517  typename _Hash, typename _RangeHash, typename _Unused,
1518  typename _RehashPolicy, typename _Traits>
1519  void
1520  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1521  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1522  swap(_Hashtable& __x)
1523  noexcept(__and_<__is_nothrow_swappable<_Hash>,
1524  __is_nothrow_swappable<_Equal>>::value)
1525  {
1526  // The only base class with member variables is hash_code_base.
1527  // We define _Hash_code_base::_M_swap because different
1528  // specializations have different members.
1529  this->_M_swap(__x);
1530 
1531  std::__alloc_on_swap(this->_M_node_allocator(), __x._M_node_allocator());
1532  std::swap(_M_rehash_policy, __x._M_rehash_policy);
1533 
1534  // Deal properly with potentially moved instances.
1535  if (this->_M_uses_single_bucket())
1536  {
1537  if (!__x._M_uses_single_bucket())
1538  {
1539  _M_buckets = __x._M_buckets;
1540  __x._M_buckets = &__x._M_single_bucket;
1541  }
1542  }
1543  else if (__x._M_uses_single_bucket())
1544  {
1545  __x._M_buckets = _M_buckets;
1546  _M_buckets = &_M_single_bucket;
1547  }
1548  else
1549  std::swap(_M_buckets, __x._M_buckets);
1550 
1551  std::swap(_M_bucket_count, __x._M_bucket_count);
1552  std::swap(_M_before_begin._M_nxt, __x._M_before_begin._M_nxt);
1553  std::swap(_M_element_count, __x._M_element_count);
1554  std::swap(_M_single_bucket, __x._M_single_bucket);
1555 
1556  // Fix buckets containing the _M_before_begin pointers that can't be
1557  // swapped.
1558  _M_update_bbegin();
1559  __x._M_update_bbegin();
1560  }
1561 
1562  template<typename _Key, typename _Value, typename _Alloc,
1563  typename _ExtractKey, typename _Equal,
1564  typename _Hash, typename _RangeHash, typename _Unused,
1565  typename _RehashPolicy, typename _Traits>
1566  auto
1567  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1568  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1569  find(const key_type& __k)
1570  -> iterator
1571  {
1572  __hash_code __code = this->_M_hash_code(__k);
1573  std::size_t __bkt = _M_bucket_index(__code);
1574  return iterator(_M_find_node(__bkt, __k, __code));
1575  }
1576 
1577  template<typename _Key, typename _Value, typename _Alloc,
1578  typename _ExtractKey, typename _Equal,
1579  typename _Hash, typename _RangeHash, typename _Unused,
1580  typename _RehashPolicy, typename _Traits>
1581  auto
1582  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1583  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1584  find(const key_type& __k) const
1585  -> const_iterator
1586  {
1587  __hash_code __code = this->_M_hash_code(__k);
1588  std::size_t __bkt = _M_bucket_index(__code);
1589  return const_iterator(_M_find_node(__bkt, __k, __code));
1590  }
1591 
1592 #if __cplusplus > 201703L
1593  template<typename _Key, typename _Value, typename _Alloc,
1594  typename _ExtractKey, typename _Equal,
1595  typename _Hash, typename _RangeHash, typename _Unused,
1596  typename _RehashPolicy, typename _Traits>
1597  template<typename _Kt, typename, typename>
1598  auto
1599  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1600  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1601  _M_find_tr(const _Kt& __k)
1602  -> iterator
1603  {
1604  __hash_code __code = this->_M_hash_code_tr(__k);
1605  std::size_t __bkt = _M_bucket_index(__code);
1606  return iterator(_M_find_node_tr(__bkt, __k, __code));
1607  }
1608 
1609  template<typename _Key, typename _Value, typename _Alloc,
1610  typename _ExtractKey, typename _Equal,
1611  typename _Hash, typename _RangeHash, typename _Unused,
1612  typename _RehashPolicy, typename _Traits>
1613  template<typename _Kt, typename, typename>
1614  auto
1615  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1616  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1617  _M_find_tr(const _Kt& __k) const
1618  -> const_iterator
1619  {
1620  __hash_code __code = this->_M_hash_code_tr(__k);
1621  std::size_t __bkt = _M_bucket_index(__code);
1622  return const_iterator(_M_find_node_tr(__bkt, __k, __code));
1623  }
1624 #endif
1625 
1626  template<typename _Key, typename _Value, typename _Alloc,
1627  typename _ExtractKey, typename _Equal,
1628  typename _Hash, typename _RangeHash, typename _Unused,
1629  typename _RehashPolicy, typename _Traits>
1630  auto
1631  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1632  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1633  count(const key_type& __k) const
1634  -> size_type
1635  {
1636  auto __it = find(__k);
1637  if (!__it._M_cur)
1638  return 0;
1639 
1640  if (__unique_keys::value)
1641  return 1;
1642 
1643  // All equivalent values are next to each other, if we find a
1644  // non-equivalent value after an equivalent one it means that we won't
1645  // find any new equivalent value.
1646  size_type __result = 1;
1647  for (auto __ref = __it++;
1648  __it._M_cur && this->_M_node_equals(*__ref._M_cur, *__it._M_cur);
1649  ++__it)
1650  ++__result;
1651 
1652  return __result;
1653  }
1654 
1655 #if __cplusplus > 201703L
1656  template<typename _Key, typename _Value, typename _Alloc,
1657  typename _ExtractKey, typename _Equal,
1658  typename _Hash, typename _RangeHash, typename _Unused,
1659  typename _RehashPolicy, typename _Traits>
1660  template<typename _Kt, typename, typename>
1661  auto
1662  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1663  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1664  _M_count_tr(const _Kt& __k) const
1665  -> size_type
1666  {
1667  __hash_code __code = this->_M_hash_code_tr(__k);
1668  std::size_t __bkt = _M_bucket_index(__code);
1669  auto __n = _M_find_node_tr(__bkt, __k, __code);
1670  if (!__n)
1671  return 0;
1672 
1673  // All equivalent values are next to each other, if we find a
1674  // non-equivalent value after an equivalent one it means that we won't
1675  // find any new equivalent value.
1676  iterator __it(__n);
1677  size_type __result = 1;
1678  for (++__it;
1679  __it._M_cur && this->_M_equals_tr(__k, __code, *__it._M_cur);
1680  ++__it)
1681  ++__result;
1682 
1683  return __result;
1684  }
1685 #endif
1686 
1687  template<typename _Key, typename _Value, typename _Alloc,
1688  typename _ExtractKey, typename _Equal,
1689  typename _Hash, typename _RangeHash, typename _Unused,
1690  typename _RehashPolicy, typename _Traits>
1691  auto
1692  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1693  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1694  equal_range(const key_type& __k)
1695  -> pair<iterator, iterator>
1696  {
1697  auto __ite = find(__k);
1698  if (!__ite._M_cur)
1699  return { __ite, __ite };
1700 
1701  auto __beg = __ite++;
1702  if (__unique_keys::value)
1703  return { __beg, __ite };
1704 
1705  // All equivalent values are next to each other, if we find a
1706  // non-equivalent value after an equivalent one it means that we won't
1707  // find any new equivalent value.
1708  while (__ite._M_cur && this->_M_node_equals(*__beg._M_cur, *__ite._M_cur))
1709  ++__ite;
1710 
1711  return { __beg, __ite };
1712  }
1713 
1714  template<typename _Key, typename _Value, typename _Alloc,
1715  typename _ExtractKey, typename _Equal,
1716  typename _Hash, typename _RangeHash, typename _Unused,
1717  typename _RehashPolicy, typename _Traits>
1718  auto
1719  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1720  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1721  equal_range(const key_type& __k) const
1722  -> pair<const_iterator, const_iterator>
1723  {
1724  auto __ite = find(__k);
1725  if (!__ite._M_cur)
1726  return { __ite, __ite };
1727 
1728  auto __beg = __ite++;
1729  if (__unique_keys::value)
1730  return { __beg, __ite };
1731 
1732  // All equivalent values are next to each other, if we find a
1733  // non-equivalent value after an equivalent one it means that we won't
1734  // find any new equivalent value.
1735  while (__ite._M_cur && this->_M_node_equals(*__beg._M_cur, *__ite._M_cur))
1736  ++__ite;
1737 
1738  return { __beg, __ite };
1739  }
1740 
1741 #if __cplusplus > 201703L
1742  template<typename _Key, typename _Value, typename _Alloc,
1743  typename _ExtractKey, typename _Equal,
1744  typename _Hash, typename _RangeHash, typename _Unused,
1745  typename _RehashPolicy, typename _Traits>
1746  template<typename _Kt, typename, typename>
1747  auto
1748  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1749  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1750  _M_equal_range_tr(const _Kt& __k)
1751  -> pair<iterator, iterator>
1752  {
1753  __hash_code __code = this->_M_hash_code_tr(__k);
1754  std::size_t __bkt = _M_bucket_index(__code);
1755  auto __n = _M_find_node_tr(__bkt, __k, __code);
1756  iterator __ite(__n);
1757  if (!__n)
1758  return { __ite, __ite };
1759 
1760  // All equivalent values are next to each other, if we find a
1761  // non-equivalent value after an equivalent one it means that we won't
1762  // find any new equivalent value.
1763  auto __beg = __ite++;
1764  while (__ite._M_cur && this->_M_equals_tr(__k, __code, *__ite._M_cur))
1765  ++__ite;
1766 
1767  return { __beg, __ite };
1768  }
1769 
1770  template<typename _Key, typename _Value, typename _Alloc,
1771  typename _ExtractKey, typename _Equal,
1772  typename _Hash, typename _RangeHash, typename _Unused,
1773  typename _RehashPolicy, typename _Traits>
1774  template<typename _Kt, typename, typename>
1775  auto
1776  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1777  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1778  _M_equal_range_tr(const _Kt& __k) const
1779  -> pair<const_iterator, const_iterator>
1780  {
1781  __hash_code __code = this->_M_hash_code_tr(__k);
1782  std::size_t __bkt = _M_bucket_index(__code);
1783  auto __n = _M_find_node_tr(__bkt, __k, __code);
1784  const_iterator __ite(__n);
1785  if (!__n)
1786  return { __ite, __ite };
1787 
1788  // All equivalent values are next to each other, if we find a
1789  // non-equivalent value after an equivalent one it means that we won't
1790  // find any new equivalent value.
1791  auto __beg = __ite++;
1792  while (__ite._M_cur && this->_M_equals_tr(__k, __code, *__ite._M_cur))
1793  ++__ite;
1794 
1795  return { __beg, __ite };
1796  }
1797 #endif
1798 
1799  // Find the node before the one whose key compares equal to k in the bucket
1800  // bkt. Return nullptr if no node is found.
1801  template<typename _Key, typename _Value, typename _Alloc,
1802  typename _ExtractKey, typename _Equal,
1803  typename _Hash, typename _RangeHash, typename _Unused,
1804  typename _RehashPolicy, typename _Traits>
1805  auto
1806  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1807  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1808  _M_find_before_node(size_type __bkt, const key_type& __k,
1809  __hash_code __code) const
1810  -> __node_base_ptr
1811  {
1812  __node_base_ptr __prev_p = _M_buckets[__bkt];
1813  if (!__prev_p)
1814  return nullptr;
1815 
1816  for (__node_ptr __p = static_cast<__node_ptr>(__prev_p->_M_nxt);;
1817  __p = __p->_M_next())
1818  {
1819  if (this->_M_equals(__k, __code, *__p))
1820  return __prev_p;
1821 
1822  if (!__p->_M_nxt || _M_bucket_index(*__p->_M_next()) != __bkt)
1823  break;
1824  __prev_p = __p;
1825  }
1826 
1827  return nullptr;
1828  }
1829 
1830  template<typename _Key, typename _Value, typename _Alloc,
1831  typename _ExtractKey, typename _Equal,
1832  typename _Hash, typename _RangeHash, typename _Unused,
1833  typename _RehashPolicy, typename _Traits>
1834  template<typename _Kt>
1835  auto
1836  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1837  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1838  _M_find_before_node_tr(size_type __bkt, const _Kt& __k,
1839  __hash_code __code) const
1840  -> __node_base_ptr
1841  {
1842  __node_base_ptr __prev_p = _M_buckets[__bkt];
1843  if (!__prev_p)
1844  return nullptr;
1845 
1846  for (__node_ptr __p = static_cast<__node_ptr>(__prev_p->_M_nxt);;
1847  __p = __p->_M_next())
1848  {
1849  if (this->_M_equals_tr(__k, __code, *__p))
1850  return __prev_p;
1851 
1852  if (!__p->_M_nxt || _M_bucket_index(*__p->_M_next()) != __bkt)
1853  break;
1854  __prev_p = __p;
1855  }
1856 
1857  return nullptr;
1858  }
1859 
1860  template<typename _Key, typename _Value, typename _Alloc,
1861  typename _ExtractKey, typename _Equal,
1862  typename _Hash, typename _RangeHash, typename _Unused,
1863  typename _RehashPolicy, typename _Traits>
1864  void
1865  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1866  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1867  _M_insert_bucket_begin(size_type __bkt, __node_ptr __node)
1868  {
1869  if (_M_buckets[__bkt])
1870  {
1871  // Bucket is not empty, we just need to insert the new node
1872  // after the bucket before begin.
1873  __node->_M_nxt = _M_buckets[__bkt]->_M_nxt;
1874  _M_buckets[__bkt]->_M_nxt = __node;
1875  }
1876  else
1877  {
1878  // The bucket is empty, the new node is inserted at the
1879  // beginning of the singly-linked list and the bucket will
1880  // contain _M_before_begin pointer.
1881  __node->_M_nxt = _M_before_begin._M_nxt;
1882  _M_before_begin._M_nxt = __node;
1883 
1884  if (__node->_M_nxt)
1885  // We must update former begin bucket that is pointing to
1886  // _M_before_begin.
1887  _M_buckets[_M_bucket_index(*__node->_M_next())] = __node;
1888 
1889  _M_buckets[__bkt] = &_M_before_begin;
1890  }
1891  }
1892 
1893  template<typename _Key, typename _Value, typename _Alloc,
1894  typename _ExtractKey, typename _Equal,
1895  typename _Hash, typename _RangeHash, typename _Unused,
1896  typename _RehashPolicy, typename _Traits>
1897  void
1898  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1899  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1900  _M_remove_bucket_begin(size_type __bkt, __node_ptr __next,
1901  size_type __next_bkt)
1902  {
1903  if (!__next || __next_bkt != __bkt)
1904  {
1905  // Bucket is now empty
1906  // First update next bucket if any
1907  if (__next)
1908  _M_buckets[__next_bkt] = _M_buckets[__bkt];
1909 
1910  // Second update before begin node if necessary
1911  if (&_M_before_begin == _M_buckets[__bkt])
1912  _M_before_begin._M_nxt = __next;
1913  _M_buckets[__bkt] = nullptr;
1914  }
1915  }
1916 
1917  template<typename _Key, typename _Value, typename _Alloc,
1918  typename _ExtractKey, typename _Equal,
1919  typename _Hash, typename _RangeHash, typename _Unused,
1920  typename _RehashPolicy, typename _Traits>
1921  auto
1922  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1923  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1924  _M_get_previous_node(size_type __bkt, __node_ptr __n)
1925  -> __node_base_ptr
1926  {
1927  __node_base_ptr __prev_n = _M_buckets[__bkt];
1928  while (__prev_n->_M_nxt != __n)
1929  __prev_n = __prev_n->_M_nxt;
1930  return __prev_n;
1931  }
1932 
1933  template<typename _Key, typename _Value, typename _Alloc,
1934  typename _ExtractKey, typename _Equal,
1935  typename _Hash, typename _RangeHash, typename _Unused,
1936  typename _RehashPolicy, typename _Traits>
1937  template<typename... _Args>
1938  auto
1939  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1940  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1941  _M_emplace(true_type /* __uks */, _Args&&... __args)
1942  -> pair<iterator, bool>
1943  {
1944  // First build the node to get access to the hash code
1945  _Scoped_node __node { this, std::forward<_Args>(__args)... };
1946  const key_type& __k = _ExtractKey{}(__node._M_node->_M_v());
1947  __hash_code __code = this->_M_hash_code(__k);
1948  size_type __bkt = _M_bucket_index(__code);
1949  if (__node_ptr __p = _M_find_node(__bkt, __k, __code))
1950  // There is already an equivalent node, no insertion
1951  return std::make_pair(iterator(__p), false);
1952 
1953  // Insert the node
1954  auto __pos = _M_insert_unique_node(__bkt, __code, __node._M_node);
1955  __node._M_node = nullptr;
1956  return { __pos, true };
1957  }
1958 
1959  template<typename _Key, typename _Value, typename _Alloc,
1960  typename _ExtractKey, typename _Equal,
1961  typename _Hash, typename _RangeHash, typename _Unused,
1962  typename _RehashPolicy, typename _Traits>
1963  template<typename... _Args>
1964  auto
1965  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1966  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1967  _M_emplace(const_iterator __hint, false_type /* __uks */,
1968  _Args&&... __args)
1969  -> iterator
1970  {
1971  // First build the node to get its hash code.
1972  _Scoped_node __node { this, std::forward<_Args>(__args)... };
1973  const key_type& __k = _ExtractKey{}(__node._M_node->_M_v());
1974 
1975  __hash_code __code = this->_M_hash_code(__k);
1976  auto __pos
1977  = _M_insert_multi_node(__hint._M_cur, __code, __node._M_node);
1978  __node._M_node = nullptr;
1979  return __pos;
1980  }
1981 
1982  template<typename _Key, typename _Value, typename _Alloc,
1983  typename _ExtractKey, typename _Equal,
1984  typename _Hash, typename _RangeHash, typename _Unused,
1985  typename _RehashPolicy, typename _Traits>
1986  auto
1987  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1988  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1989  _M_insert_unique_node(size_type __bkt, __hash_code __code,
1990  __node_ptr __node, size_type __n_elt)
1991  -> iterator
1992  {
1993  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
1994  std::pair<bool, std::size_t> __do_rehash
1995  = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count,
1996  __n_elt);
1997 
1998  if (__do_rehash.first)
1999  {
2000  _M_rehash(__do_rehash.second, __saved_state);
2001  __bkt = _M_bucket_index(__code);
2002  }
2003 
2004  this->_M_store_code(*__node, __code);
2005 
2006  // Always insert at the beginning of the bucket.
2007  _M_insert_bucket_begin(__bkt, __node);
2008  ++_M_element_count;
2009  return iterator(__node);
2010  }
2011 
2012  template<typename _Key, typename _Value, typename _Alloc,
2013  typename _ExtractKey, typename _Equal,
2014  typename _Hash, typename _RangeHash, typename _Unused,
2015  typename _RehashPolicy, typename _Traits>
2016  auto
2017  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2018  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2019  _M_insert_multi_node(__node_ptr __hint,
2020  __hash_code __code, __node_ptr __node)
2021  -> iterator
2022  {
2023  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
2024  std::pair<bool, std::size_t> __do_rehash
2025  = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count, 1);
2026 
2027  if (__do_rehash.first)
2028  _M_rehash(__do_rehash.second, __saved_state);
2029 
2030  this->_M_store_code(*__node, __code);
2031  const key_type& __k = _ExtractKey{}(__node->_M_v());
2032  size_type __bkt = _M_bucket_index(__code);
2033 
2034  // Find the node before an equivalent one or use hint if it exists and
2035  // if it is equivalent.
2036  __node_base_ptr __prev
2037  = __builtin_expect(__hint != nullptr, false)
2038  && this->_M_equals(__k, __code, *__hint)
2039  ? __hint
2040  : _M_find_before_node(__bkt, __k, __code);
2041 
2042  if (__prev)
2043  {
2044  // Insert after the node before the equivalent one.
2045  __node->_M_nxt = __prev->_M_nxt;
2046  __prev->_M_nxt = __node;
2047  if (__builtin_expect(__prev == __hint, false))
2048  // hint might be the last bucket node, in this case we need to
2049  // update next bucket.
2050  if (__node->_M_nxt
2051  && !this->_M_equals(__k, __code, *__node->_M_next()))
2052  {
2053  size_type __next_bkt = _M_bucket_index(*__node->_M_next());
2054  if (__next_bkt != __bkt)
2055  _M_buckets[__next_bkt] = __node;
2056  }
2057  }
2058  else
2059  // The inserted node has no equivalent in the hashtable. We must
2060  // insert the new node at the beginning of the bucket to preserve
2061  // equivalent elements' relative positions.
2062  _M_insert_bucket_begin(__bkt, __node);
2063  ++_M_element_count;
2064  return iterator(__node);
2065  }
2066 
2067  // Insert v if no element with its key is already present.
2068  template<typename _Key, typename _Value, typename _Alloc,
2069  typename _ExtractKey, typename _Equal,
2070  typename _Hash, typename _RangeHash, typename _Unused,
2071  typename _RehashPolicy, typename _Traits>
2072  template<typename _Arg, typename _NodeGenerator>
2073  auto
2074  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2075  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2076  _M_insert(_Arg&& __v, const _NodeGenerator& __node_gen,
2077  true_type /* __uks */)
2078  -> pair<iterator, bool>
2079  {
2080  const key_type& __k = _ExtractKey{}(__v);
2081  __hash_code __code = this->_M_hash_code(__k);
2082  size_type __bkt = _M_bucket_index(__code);
2083 
2084  if (__node_ptr __node = _M_find_node(__bkt, __k, __code))
2085  return { iterator(__node), false };
2086 
2087  _Scoped_node __node{ __node_gen(std::forward<_Arg>(__v)), this };
2088  auto __pos
2089  = _M_insert_unique_node(__bkt, __code, __node._M_node);
2090  __node._M_node = nullptr;
2091  return { __pos, true };
2092  }
2093 
2094  // Insert v unconditionally.
2095  template<typename _Key, typename _Value, typename _Alloc,
2096  typename _ExtractKey, typename _Equal,
2097  typename _Hash, typename _RangeHash, typename _Unused,
2098  typename _RehashPolicy, typename _Traits>
2099  template<typename _Arg, typename _NodeGenerator>
2100  auto
2101  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2102  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2103  _M_insert(const_iterator __hint, _Arg&& __v,
2104  const _NodeGenerator& __node_gen,
2105  false_type /* __uks */)
2106  -> iterator
2107  {
2108  // First compute the hash code so that we don't do anything if it
2109  // throws.
2110  __hash_code __code = this->_M_hash_code(_ExtractKey{}(__v));
2111 
2112  // Second allocate new node so that we don't rehash if it throws.
2113  _Scoped_node __node{ __node_gen(std::forward<_Arg>(__v)), this };
2114  auto __pos
2115  = _M_insert_multi_node(__hint._M_cur, __code, __node._M_node);
2116  __node._M_node = nullptr;
2117  return __pos;
2118  }
2119 
2120  template<typename _Key, typename _Value, typename _Alloc,
2121  typename _ExtractKey, typename _Equal,
2122  typename _Hash, typename _RangeHash, typename _Unused,
2123  typename _RehashPolicy, typename _Traits>
2124  auto
2125  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2126  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2127  erase(const_iterator __it)
2128  -> iterator
2129  {
2130  __node_ptr __n = __it._M_cur;
2131  std::size_t __bkt = _M_bucket_index(*__n);
2132 
2133  // Look for previous node to unlink it from the erased one, this
2134  // is why we need buckets to contain the before begin to make
2135  // this search fast.
2136  __node_base_ptr __prev_n = _M_get_previous_node(__bkt, __n);
2137  return _M_erase(__bkt, __prev_n, __n);
2138  }
2139 
2140  template<typename _Key, typename _Value, typename _Alloc,
2141  typename _ExtractKey, typename _Equal,
2142  typename _Hash, typename _RangeHash, typename _Unused,
2143  typename _RehashPolicy, typename _Traits>
2144  auto
2145  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2146  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2147  _M_erase(size_type __bkt, __node_base_ptr __prev_n, __node_ptr __n)
2148  -> iterator
2149  {
2150  if (__prev_n == _M_buckets[__bkt])
2151  _M_remove_bucket_begin(__bkt, __n->_M_next(),
2152  __n->_M_nxt ? _M_bucket_index(*__n->_M_next()) : 0);
2153  else if (__n->_M_nxt)
2154  {
2155  size_type __next_bkt = _M_bucket_index(*__n->_M_next());
2156  if (__next_bkt != __bkt)
2157  _M_buckets[__next_bkt] = __prev_n;
2158  }
2159 
2160  __prev_n->_M_nxt = __n->_M_nxt;
2161  iterator __result(__n->_M_next());
2162  this->_M_deallocate_node(__n);
2163  --_M_element_count;
2164 
2165  return __result;
2166  }
2167 
2168  template<typename _Key, typename _Value, typename _Alloc,
2169  typename _ExtractKey, typename _Equal,
2170  typename _Hash, typename _RangeHash, typename _Unused,
2171  typename _RehashPolicy, typename _Traits>
2172  auto
2173  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2174  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2175  _M_erase(true_type /* __uks */, const key_type& __k)
2176  -> size_type
2177  {
2178  __hash_code __code = this->_M_hash_code(__k);
2179  std::size_t __bkt = _M_bucket_index(__code);
2180 
2181  // Look for the node before the first matching node.
2182  __node_base_ptr __prev_n = _M_find_before_node(__bkt, __k, __code);
2183  if (!__prev_n)
2184  return 0;
2185 
2186  // We found a matching node, erase it.
2187  __node_ptr __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
2188  _M_erase(__bkt, __prev_n, __n);
2189  return 1;
2190  }
2191 
2192  template<typename _Key, typename _Value, typename _Alloc,
2193  typename _ExtractKey, typename _Equal,
2194  typename _Hash, typename _RangeHash, typename _Unused,
2195  typename _RehashPolicy, typename _Traits>
2196  auto
2197  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2198  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2199  _M_erase(false_type /* __uks */, const key_type& __k)
2200  -> size_type
2201  {
2202  __hash_code __code = this->_M_hash_code(__k);
2203  std::size_t __bkt = _M_bucket_index(__code);
2204 
2205  // Look for the node before the first matching node.
2206  __node_base_ptr __prev_n = _M_find_before_node(__bkt, __k, __code);
2207  if (!__prev_n)
2208  return 0;
2209 
2210  // _GLIBCXX_RESOLVE_LIB_DEFECTS
2211  // 526. Is it undefined if a function in the standard changes
2212  // in parameters?
2213  // We use one loop to find all matching nodes and another to deallocate
2214  // them so that the key stays valid during the first loop. It might be
2215  // invalidated indirectly when destroying nodes.
2216  __node_ptr __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
2217  __node_ptr __n_last = __n->_M_next();
2218  while (__n_last && this->_M_node_equals(*__n, *__n_last))
2219  __n_last = __n_last->_M_next();
2220 
2221  std::size_t __n_last_bkt = __n_last ? _M_bucket_index(*__n_last) : __bkt;
2222 
2223  // Deallocate nodes.
2224  size_type __result = 0;
2225  do
2226  {
2227  __node_ptr __p = __n->_M_next();
2228  this->_M_deallocate_node(__n);
2229  __n = __p;
2230  ++__result;
2231  }
2232  while (__n != __n_last);
2233 
2234  _M_element_count -= __result;
2235  if (__prev_n == _M_buckets[__bkt])
2236  _M_remove_bucket_begin(__bkt, __n_last, __n_last_bkt);
2237  else if (__n_last_bkt != __bkt)
2238  _M_buckets[__n_last_bkt] = __prev_n;
2239  __prev_n->_M_nxt = __n_last;
2240  return __result;
2241  }
2242 
2243  template<typename _Key, typename _Value, typename _Alloc,
2244  typename _ExtractKey, typename _Equal,
2245  typename _Hash, typename _RangeHash, typename _Unused,
2246  typename _RehashPolicy, typename _Traits>
2247  auto
2248  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2249  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2250  erase(const_iterator __first, const_iterator __last)
2251  -> iterator
2252  {
2253  __node_ptr __n = __first._M_cur;
2254  __node_ptr __last_n = __last._M_cur;
2255  if (__n == __last_n)
2256  return iterator(__n);
2257 
2258  std::size_t __bkt = _M_bucket_index(*__n);
2259 
2260  __node_base_ptr __prev_n = _M_get_previous_node(__bkt, __n);
2261  bool __is_bucket_begin = __n == _M_bucket_begin(__bkt);
2262  std::size_t __n_bkt = __bkt;
2263  for (;;)
2264  {
2265  do
2266  {
2267  __node_ptr __tmp = __n;
2268  __n = __n->_M_next();
2269  this->_M_deallocate_node(__tmp);
2270  --_M_element_count;
2271  if (!__n)
2272  break;
2273  __n_bkt = _M_bucket_index(*__n);
2274  }
2275  while (__n != __last_n && __n_bkt == __bkt);
2276  if (__is_bucket_begin)
2277  _M_remove_bucket_begin(__bkt, __n, __n_bkt);
2278  if (__n == __last_n)
2279  break;
2280  __is_bucket_begin = true;
2281  __bkt = __n_bkt;
2282  }
2283 
2284  if (__n && (__n_bkt != __bkt || __is_bucket_begin))
2285  _M_buckets[__n_bkt] = __prev_n;
2286  __prev_n->_M_nxt = __n;
2287  return iterator(__n);
2288  }
2289 
2290  template<typename _Key, typename _Value, typename _Alloc,
2291  typename _ExtractKey, typename _Equal,
2292  typename _Hash, typename _RangeHash, typename _Unused,
2293  typename _RehashPolicy, typename _Traits>
2294  void
2295  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2296  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2297  clear() noexcept
2298  {
2299  this->_M_deallocate_nodes(_M_begin());
2300  __builtin_memset(_M_buckets, 0,
2301  _M_bucket_count * sizeof(__node_base_ptr));
2302  _M_element_count = 0;
2303  _M_before_begin._M_nxt = nullptr;
2304  }
2305 
2306  template<typename _Key, typename _Value, typename _Alloc,
2307  typename _ExtractKey, typename _Equal,
2308  typename _Hash, typename _RangeHash, typename _Unused,
2309  typename _RehashPolicy, typename _Traits>
2310  void
2311  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2312  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2313  rehash(size_type __bkt_count)
2314  {
2315  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
2316  __bkt_count
2317  = std::max(_M_rehash_policy._M_bkt_for_elements(_M_element_count + 1),
2318  __bkt_count);
2319  __bkt_count = _M_rehash_policy._M_next_bkt(__bkt_count);
2320 
2321  if (__bkt_count != _M_bucket_count)
2322  _M_rehash(__bkt_count, __saved_state);
2323  else
2324  // No rehash, restore previous state to keep it consistent with
2325  // container state.
2326  _M_rehash_policy._M_reset(__saved_state);
2327  }
2328 
2329  template<typename _Key, typename _Value, typename _Alloc,
2330  typename _ExtractKey, typename _Equal,
2331  typename _Hash, typename _RangeHash, typename _Unused,
2332  typename _RehashPolicy, typename _Traits>
2333  void
2334  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2335  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2336  _M_rehash(size_type __bkt_count, const __rehash_state& __state)
2337  {
2338  __try
2339  {
2340  _M_rehash_aux(__bkt_count, __unique_keys{});
2341  }
2342  __catch(...)
2343  {
2344  // A failure here means that buckets allocation failed. We only
2345  // have to restore hash policy previous state.
2346  _M_rehash_policy._M_reset(__state);
2347  __throw_exception_again;
2348  }
2349  }
2350 
2351  // Rehash when there is no equivalent elements.
2352  template<typename _Key, typename _Value, typename _Alloc,
2353  typename _ExtractKey, typename _Equal,
2354  typename _Hash, typename _RangeHash, typename _Unused,
2355  typename _RehashPolicy, typename _Traits>
2356  void
2357  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2358  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2359  _M_rehash_aux(size_type __bkt_count, true_type /* __uks */)
2360  {
2361  __buckets_ptr __new_buckets = _M_allocate_buckets(__bkt_count);
2362  __node_ptr __p = _M_begin();
2363  _M_before_begin._M_nxt = nullptr;
2364  std::size_t __bbegin_bkt = 0;
2365  while (__p)
2366  {
2367  __node_ptr __next = __p->_M_next();
2368  std::size_t __bkt
2369  = __hash_code_base::_M_bucket_index(*__p, __bkt_count);
2370  if (!__new_buckets[__bkt])
2371  {
2372  __p->_M_nxt = _M_before_begin._M_nxt;
2373  _M_before_begin._M_nxt = __p;
2374  __new_buckets[__bkt] = &_M_before_begin;
2375  if (__p->_M_nxt)
2376  __new_buckets[__bbegin_bkt] = __p;
2377  __bbegin_bkt = __bkt;
2378  }
2379  else
2380  {
2381  __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
2382  __new_buckets[__bkt]->_M_nxt = __p;
2383  }
2384 
2385  __p = __next;
2386  }
2387 
2388  _M_deallocate_buckets();
2389  _M_bucket_count = __bkt_count;
2390  _M_buckets = __new_buckets;
2391  }
2392 
2393  // Rehash when there can be equivalent elements, preserve their relative
2394  // order.
2395  template<typename _Key, typename _Value, typename _Alloc,
2396  typename _ExtractKey, typename _Equal,
2397  typename _Hash, typename _RangeHash, typename _Unused,
2398  typename _RehashPolicy, typename _Traits>
2399  void
2400  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2401  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2402  _M_rehash_aux(size_type __bkt_count, false_type /* __uks */)
2403  {
2404  __buckets_ptr __new_buckets = _M_allocate_buckets(__bkt_count);
2405  __node_ptr __p = _M_begin();
2406  _M_before_begin._M_nxt = nullptr;
2407  std::size_t __bbegin_bkt = 0;
2408  std::size_t __prev_bkt = 0;
2409  __node_ptr __prev_p = nullptr;
2410  bool __check_bucket = false;
2411 
2412  while (__p)
2413  {
2414  __node_ptr __next = __p->_M_next();
2415  std::size_t __bkt
2416  = __hash_code_base::_M_bucket_index(*__p, __bkt_count);
2417 
2418  if (__prev_p && __prev_bkt == __bkt)
2419  {
2420  // Previous insert was already in this bucket, we insert after
2421  // the previously inserted one to preserve equivalent elements
2422  // relative order.
2423  __p->_M_nxt = __prev_p->_M_nxt;
2424  __prev_p->_M_nxt = __p;
2425 
2426  // Inserting after a node in a bucket require to check that we
2427  // haven't change the bucket last node, in this case next
2428  // bucket containing its before begin node must be updated. We
2429  // schedule a check as soon as we move out of the sequence of
2430  // equivalent nodes to limit the number of checks.
2431  __check_bucket = true;
2432  }
2433  else
2434  {
2435  if (__check_bucket)
2436  {
2437  // Check if we shall update the next bucket because of
2438  // insertions into __prev_bkt bucket.
2439  if (__prev_p->_M_nxt)
2440  {
2441  std::size_t __next_bkt
2442  = __hash_code_base::_M_bucket_index(
2443  *__prev_p->_M_next(), __bkt_count);
2444  if (__next_bkt != __prev_bkt)
2445  __new_buckets[__next_bkt] = __prev_p;
2446  }
2447  __check_bucket = false;
2448  }
2449 
2450  if (!__new_buckets[__bkt])
2451  {
2452  __p->_M_nxt = _M_before_begin._M_nxt;
2453  _M_before_begin._M_nxt = __p;
2454  __new_buckets[__bkt] = &_M_before_begin;
2455  if (__p->_M_nxt)
2456  __new_buckets[__bbegin_bkt] = __p;
2457  __bbegin_bkt = __bkt;
2458  }
2459  else
2460  {
2461  __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
2462  __new_buckets[__bkt]->_M_nxt = __p;
2463  }
2464  }
2465  __prev_p = __p;
2466  __prev_bkt = __bkt;
2467  __p = __next;
2468  }
2469 
2470  if (__check_bucket && __prev_p->_M_nxt)
2471  {
2472  std::size_t __next_bkt
2473  = __hash_code_base::_M_bucket_index(*__prev_p->_M_next(),
2474  __bkt_count);
2475  if (__next_bkt != __prev_bkt)
2476  __new_buckets[__next_bkt] = __prev_p;
2477  }
2478 
2479  _M_deallocate_buckets();
2480  _M_bucket_count = __bkt_count;
2481  _M_buckets = __new_buckets;
2482  }
2483 
2484 #if __cplusplus > 201402L
2485  template<typename, typename, typename> class _Hash_merge_helper { };
2486 #endif // C++17
2487 
2488 #if __cpp_deduction_guides >= 201606
2489  // Used to constrain deduction guides
2490  template<typename _Hash>
2491  using _RequireNotAllocatorOrIntegral
2492  = __enable_if_t<!__or_<is_integral<_Hash>, __is_allocator<_Hash>>::value>;
2493 #endif
2494 
2495 _GLIBCXX_END_NAMESPACE_VERSION
2496 } // namespace std
2497 
2498 #endif // _HASHTABLE_H
void swap(shared_lock< _Mutex > &__x, shared_lock< _Mutex > &__y) noexcept
Swap specialization for shared_lock.
Definition: shared_mutex:851
constexpr auto cbegin(const _Container &__cont) noexcept(noexcept(std::begin(__cont))) -> decltype(std::begin(__cont))
Return an iterator pointing to the first element of the const container.
Definition: range_access.h:119
insert_return_type _M_reinsert_node(node_type &&__nh)
Re-insert an extracted node into a container with unique keys.
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:104
is_nothrow_default_constructible
Definition: type_traits:984
constexpr iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
iterator _M_reinsert_node_multi(const_iterator __hint, node_type &&__nh)
Re-insert an extracted node into a container with equivalent keys.
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:75
Common iterator class.
is_nothrow_copy_constructible
Definition: type_traits:1006
node_type extract(const _Key &__k)
Extract a node.
Uniform interface to C++98 and C++11 allocators.
_Tp * begin(valarray< _Tp > &__va)
Return an iterator pointing to the first element of the valarray.
Definition: valarray:1214
_Tp * end(valarray< _Tp > &__va)
Return an iterator pointing to one past the last element of the valarray.
Definition: valarray:1234
is_same
Definition: type_traits:585
Define a member typedef type to one of two argument types.
Definition: type_traits:92
constexpr auto cend(const _Container &__cont) noexcept(noexcept(std::end(__cont))) -> decltype(std::end(__cont))
Return an iterator pointing to one past the last element of the const container.
Definition: range_access.h:130
void _M_merge_unique(_Compatible_Hashtable &__src) noexcept
Merge from a compatible container into one with unique keys.
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:78
constexpr auto empty(const _Container &__cont) noexcept(noexcept(__cont.empty())) -> decltype(__cont.empty())
Return whether a container is empty.
Definition: range_access.h:263
_T2 second
The second member.
Definition: stl_pair.h:218
constexpr const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:254
_T1 first
The first member.
Definition: stl_pair.h:217
initializer_list
Node handle type for maps.
Definition: node_handle.h:221
integral_constant
Definition: type_traits:57
void _M_merge_multi(_Compatible_Hashtable &__src) noexcept
Merge from a compatible container into one with equivalent keys.
Return type of insert(node_handle&amp;&amp;) on unique maps/sets.
Definition: node_handle.h:363
constexpr enable_if< __and_< __is_swappable< _T1 >, __is_swappable< _T2 > >::value >::type noexcept(noexcept(__x.swap(__y)))
Definition: stl_pair.h:534
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
Definition: move.h:49
constexpr auto size(const _Container &__cont) noexcept(noexcept(__cont.size())) -> decltype(__cont.size())
Return the size of a container.
Definition: range_access.h:245
is_nothrow_move_assignable
Definition: type_traits:1133
auto_ptr & operator=(auto_ptr &__a)
auto_ptr assignment operator.
Definition: auto_ptr.h:128