libstdc++
bits/hashtable.h
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1 // hashtable.h header -*- C++ -*-
2 
3 // Copyright (C) 2007-2023 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
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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>
37 #include <bits/stl_function.h> // __has_is_transparent_t
38 #if __cplusplus > 201402L
39 # include <bits/node_handle.h>
40 #endif
41 
42 namespace std _GLIBCXX_VISIBILITY(default)
43 {
44 _GLIBCXX_BEGIN_NAMESPACE_VERSION
45 /// @cond undocumented
46 
47  template<typename _Tp, typename _Hash>
48  using __cache_default
49  = __not_<__and_<// Do not cache for fast hasher.
50  __is_fast_hash<_Hash>,
51  // Mandatory to have erase not throwing.
52  __is_nothrow_invocable<const _Hash&, const _Tp&>>>;
53 
54  // Helper to conditionally delete the default constructor.
55  // The _Hash_node_base type is used to distinguish this specialization
56  // from any other potentially-overlapping subobjects of the hashtable.
57  template<typename _Equal, typename _Hash, typename _Allocator>
58  using _Hashtable_enable_default_ctor
59  = _Enable_default_constructor<__and_<is_default_constructible<_Equal>,
60  is_default_constructible<_Hash>,
61  is_default_constructible<_Allocator>>{},
62  __detail::_Hash_node_base>;
63 
64  /**
65  * Primary class template _Hashtable.
66  *
67  * @ingroup hashtable-detail
68  *
69  * @tparam _Value CopyConstructible type.
70  *
71  * @tparam _Key CopyConstructible type.
72  *
73  * @tparam _Alloc An allocator type
74  * ([lib.allocator.requirements]) whose _Alloc::value_type is
75  * _Value. As a conforming extension, we allow for
76  * _Alloc::value_type != _Value.
77  *
78  * @tparam _ExtractKey Function object that takes an object of type
79  * _Value and returns a value of type _Key.
80  *
81  * @tparam _Equal Function object that takes two objects of type k
82  * and returns a bool-like value that is true if the two objects
83  * are considered equal.
84  *
85  * @tparam _Hash The hash function. A unary function object with
86  * argument type _Key and result type size_t. Return values should
87  * be distributed over the entire range [0, numeric_limits<size_t>:::max()].
88  *
89  * @tparam _RangeHash The range-hashing function (in the terminology of
90  * Tavori and Dreizin). A binary function object whose argument
91  * types and result type are all size_t. Given arguments r and N,
92  * the return value is in the range [0, N).
93  *
94  * @tparam _Unused Not used.
95  *
96  * @tparam _RehashPolicy Policy class with three members, all of
97  * which govern the bucket count. _M_next_bkt(n) returns a bucket
98  * count no smaller than n. _M_bkt_for_elements(n) returns a
99  * bucket count appropriate for an element count of n.
100  * _M_need_rehash(n_bkt, n_elt, n_ins) determines whether, if the
101  * current bucket count is n_bkt and the current element count is
102  * n_elt, we need to increase the bucket count for n_ins insertions.
103  * If so, returns make_pair(true, n), where n is the new bucket count. If
104  * not, returns make_pair(false, <anything>)
105  *
106  * @tparam _Traits Compile-time class with three boolean
107  * std::integral_constant members: __cache_hash_code, __constant_iterators,
108  * __unique_keys.
109  *
110  * Each _Hashtable data structure has:
111  *
112  * - _Bucket[] _M_buckets
113  * - _Hash_node_base _M_before_begin
114  * - size_type _M_bucket_count
115  * - size_type _M_element_count
116  *
117  * with _Bucket being _Hash_node_base* and _Hash_node containing:
118  *
119  * - _Hash_node* _M_next
120  * - Tp _M_value
121  * - size_t _M_hash_code if cache_hash_code is true
122  *
123  * In terms of Standard containers the hashtable is like the aggregation of:
124  *
125  * - std::forward_list<_Node> containing the elements
126  * - std::vector<std::forward_list<_Node>::iterator> representing the buckets
127  *
128  * The non-empty buckets contain the node before the first node in the
129  * bucket. This design makes it possible to implement something like a
130  * std::forward_list::insert_after on container insertion and
131  * std::forward_list::erase_after on container erase
132  * calls. _M_before_begin is equivalent to
133  * std::forward_list::before_begin. Empty buckets contain
134  * nullptr. Note that one of the non-empty buckets contains
135  * &_M_before_begin which is not a dereferenceable node so the
136  * node pointer in a bucket shall never be dereferenced, only its
137  * next node can be.
138  *
139  * Walking through a bucket's nodes requires a check on the hash code to
140  * see if each node is still in the bucket. Such a design assumes a
141  * quite efficient hash functor and is one of the reasons it is
142  * highly advisable to set __cache_hash_code to true.
143  *
144  * The container iterators are simply built from nodes. This way
145  * incrementing the iterator is perfectly efficient independent of
146  * how many empty buckets there are in the container.
147  *
148  * On insert we compute the element's hash code and use it to find the
149  * bucket index. If the element must be inserted in an empty bucket
150  * we add it at the beginning of the singly linked list and make the
151  * bucket point to _M_before_begin. The bucket that used to point to
152  * _M_before_begin, if any, is updated to point to its new before
153  * begin node.
154  *
155  * On erase, the simple iterator design requires using the hash
156  * functor to get the index of the bucket to update. For this
157  * reason, when __cache_hash_code is set to false the hash functor must
158  * not throw and this is enforced by a static assertion.
159  *
160  * Functionality is implemented by decomposition into base classes,
161  * where the derived _Hashtable class is used in _Map_base,
162  * _Insert, _Rehash_base, and _Equality base classes to access the
163  * "this" pointer. _Hashtable_base is used in the base classes as a
164  * non-recursive, fully-completed-type so that detailed nested type
165  * information, such as iterator type and node type, can be
166  * used. This is similar to the "Curiously Recurring Template
167  * Pattern" (CRTP) technique, but uses a reconstructed, not
168  * explicitly passed, template pattern.
169  *
170  * Base class templates are:
171  * - __detail::_Hashtable_base
172  * - __detail::_Map_base
173  * - __detail::_Insert
174  * - __detail::_Rehash_base
175  * - __detail::_Equality
176  */
177  template<typename _Key, typename _Value, typename _Alloc,
178  typename _ExtractKey, typename _Equal,
179  typename _Hash, typename _RangeHash, typename _Unused,
180  typename _RehashPolicy, typename _Traits>
181  class _Hashtable
182  : public __detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal,
183  _Hash, _RangeHash, _Unused, _Traits>,
184  public __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
185  _Hash, _RangeHash, _Unused,
186  _RehashPolicy, _Traits>,
187  public __detail::_Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
188  _Hash, _RangeHash, _Unused,
189  _RehashPolicy, _Traits>,
190  public __detail::_Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
191  _Hash, _RangeHash, _Unused,
192  _RehashPolicy, _Traits>,
193  public __detail::_Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
194  _Hash, _RangeHash, _Unused,
195  _RehashPolicy, _Traits>,
196  private __detail::_Hashtable_alloc<
197  __alloc_rebind<_Alloc,
198  __detail::_Hash_node<_Value,
199  _Traits::__hash_cached::value>>>,
200  private _Hashtable_enable_default_ctor<_Equal, _Hash, _Alloc>
201  {
202  static_assert(is_same<typename remove_cv<_Value>::type, _Value>::value,
203  "unordered container must have a non-const, non-volatile value_type");
204 #if __cplusplus > 201703L || defined __STRICT_ANSI__
205  static_assert(is_same<typename _Alloc::value_type, _Value>{},
206  "unordered container must have the same value_type as its allocator");
207 #endif
208 
209  using __traits_type = _Traits;
210  using __hash_cached = typename __traits_type::__hash_cached;
211  using __constant_iterators = typename __traits_type::__constant_iterators;
212  using __node_type = __detail::_Hash_node<_Value, __hash_cached::value>;
213  using __node_alloc_type = __alloc_rebind<_Alloc, __node_type>;
214 
215  using __hashtable_alloc = __detail::_Hashtable_alloc<__node_alloc_type>;
216 
217  using __node_value_type =
218  __detail::_Hash_node_value<_Value, __hash_cached::value>;
219  using __node_ptr = typename __hashtable_alloc::__node_ptr;
220  using __value_alloc_traits =
221  typename __hashtable_alloc::__value_alloc_traits;
222  using __node_alloc_traits =
223  typename __hashtable_alloc::__node_alloc_traits;
224  using __node_base = typename __hashtable_alloc::__node_base;
225  using __node_base_ptr = typename __hashtable_alloc::__node_base_ptr;
226  using __buckets_ptr = typename __hashtable_alloc::__buckets_ptr;
227 
228  using __insert_base = __detail::_Insert<_Key, _Value, _Alloc, _ExtractKey,
229  _Equal, _Hash,
230  _RangeHash, _Unused,
231  _RehashPolicy, _Traits>;
232  using __enable_default_ctor
233  = _Hashtable_enable_default_ctor<_Equal, _Hash, _Alloc>;
234 
235  public:
236  typedef _Key key_type;
237  typedef _Value value_type;
238  typedef _Alloc allocator_type;
239  typedef _Equal key_equal;
240 
241  // mapped_type, if present, comes from _Map_base.
242  // hasher, if present, comes from _Hash_code_base/_Hashtable_base.
243  typedef typename __value_alloc_traits::pointer pointer;
244  typedef typename __value_alloc_traits::const_pointer const_pointer;
245  typedef value_type& reference;
246  typedef const value_type& const_reference;
247 
248  using iterator = typename __insert_base::iterator;
249 
250  using const_iterator = typename __insert_base::const_iterator;
251 
252  using local_iterator = __detail::_Local_iterator<key_type, _Value,
253  _ExtractKey, _Hash, _RangeHash, _Unused,
254  __constant_iterators::value,
255  __hash_cached::value>;
256 
257  using const_local_iterator = __detail::_Local_const_iterator<
258  key_type, _Value,
259  _ExtractKey, _Hash, _RangeHash, _Unused,
260  __constant_iterators::value, __hash_cached::value>;
261 
262  private:
263  using __rehash_type = _RehashPolicy;
264  using __rehash_state = typename __rehash_type::_State;
265 
266  using __unique_keys = typename __traits_type::__unique_keys;
267 
268  using __hashtable_base = __detail::
269  _Hashtable_base<_Key, _Value, _ExtractKey,
270  _Equal, _Hash, _RangeHash, _Unused, _Traits>;
271 
272  using __hash_code_base = typename __hashtable_base::__hash_code_base;
273  using __hash_code = typename __hashtable_base::__hash_code;
274  using __ireturn_type = typename __insert_base::__ireturn_type;
275 
276  using __map_base = __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey,
277  _Equal, _Hash, _RangeHash, _Unused,
278  _RehashPolicy, _Traits>;
279 
280  using __rehash_base = __detail::_Rehash_base<_Key, _Value, _Alloc,
281  _ExtractKey, _Equal,
282  _Hash, _RangeHash, _Unused,
283  _RehashPolicy, _Traits>;
284 
285  using __eq_base = __detail::_Equality<_Key, _Value, _Alloc, _ExtractKey,
286  _Equal, _Hash, _RangeHash, _Unused,
287  _RehashPolicy, _Traits>;
288 
289  using __reuse_or_alloc_node_gen_t =
290  __detail::_ReuseOrAllocNode<__node_alloc_type>;
291  using __alloc_node_gen_t =
292  __detail::_AllocNode<__node_alloc_type>;
293  using __node_builder_t =
294  __detail::_NodeBuilder<_ExtractKey>;
295 
296  // Simple RAII type for managing a node containing an element
297  struct _Scoped_node
298  {
299  // Take ownership of a node with a constructed element.
300  _Scoped_node(__node_ptr __n, __hashtable_alloc* __h)
301  : _M_h(__h), _M_node(__n) { }
302 
303  // Allocate a node and construct an element within it.
304  template<typename... _Args>
305  _Scoped_node(__hashtable_alloc* __h, _Args&&... __args)
306  : _M_h(__h),
307  _M_node(__h->_M_allocate_node(std::forward<_Args>(__args)...))
308  { }
309 
310  // Destroy element and deallocate node.
311  ~_Scoped_node() { if (_M_node) _M_h->_M_deallocate_node(_M_node); };
312 
313  _Scoped_node(const _Scoped_node&) = delete;
314  _Scoped_node& operator=(const _Scoped_node&) = delete;
315 
316  __hashtable_alloc* _M_h;
317  __node_ptr _M_node;
318  };
319 
320  template<typename _Ht>
321  static constexpr
322  __conditional_t<std::is_lvalue_reference<_Ht>::value,
323  const value_type&, value_type&&>
324  __fwd_value_for(value_type& __val) noexcept
325  { return std::move(__val); }
326 
327  // Compile-time diagnostics.
328 
329  // _Hash_code_base has everything protected, so use this derived type to
330  // access it.
331  struct __hash_code_base_access : __hash_code_base
332  { using __hash_code_base::_M_bucket_index; };
333 
334  // To get bucket index we need _RangeHash not to throw.
335  static_assert(is_nothrow_default_constructible<_RangeHash>::value,
336  "Functor used to map hash code to bucket index"
337  " must be nothrow default constructible");
338  static_assert(noexcept(
339  std::declval<const _RangeHash&>()((std::size_t)0, (std::size_t)0)),
340  "Functor used to map hash code to bucket index must be"
341  " noexcept");
342 
343  // To compute bucket index we also need _ExtratKey not to throw.
344  static_assert(is_nothrow_default_constructible<_ExtractKey>::value,
345  "_ExtractKey must be nothrow default constructible");
346  static_assert(noexcept(
347  std::declval<const _ExtractKey&>()(std::declval<_Value>())),
348  "_ExtractKey functor must be noexcept invocable");
349 
350  template<typename _Keya, typename _Valuea, typename _Alloca,
351  typename _ExtractKeya, typename _Equala,
352  typename _Hasha, typename _RangeHasha, typename _Unuseda,
353  typename _RehashPolicya, typename _Traitsa,
354  bool _Unique_keysa>
355  friend struct __detail::_Map_base;
356 
357  template<typename _Keya, typename _Valuea, typename _Alloca,
358  typename _ExtractKeya, typename _Equala,
359  typename _Hasha, typename _RangeHasha, typename _Unuseda,
360  typename _RehashPolicya, typename _Traitsa>
361  friend struct __detail::_Insert_base;
362 
363  template<typename _Keya, typename _Valuea, typename _Alloca,
364  typename _ExtractKeya, typename _Equala,
365  typename _Hasha, typename _RangeHasha, typename _Unuseda,
366  typename _RehashPolicya, typename _Traitsa,
367  bool _Constant_iteratorsa>
368  friend struct __detail::_Insert;
369 
370  template<typename _Keya, typename _Valuea, typename _Alloca,
371  typename _ExtractKeya, typename _Equala,
372  typename _Hasha, typename _RangeHasha, typename _Unuseda,
373  typename _RehashPolicya, typename _Traitsa,
374  bool _Unique_keysa>
375  friend struct __detail::_Equality;
376 
377  public:
378  using size_type = typename __hashtable_base::size_type;
379  using difference_type = typename __hashtable_base::difference_type;
380 
381 #if __cplusplus > 201402L
382  using node_type = _Node_handle<_Key, _Value, __node_alloc_type>;
383  using insert_return_type = _Node_insert_return<iterator, node_type>;
384 #endif
385 
386  private:
387  __buckets_ptr _M_buckets = &_M_single_bucket;
388  size_type _M_bucket_count = 1;
389  __node_base _M_before_begin;
390  size_type _M_element_count = 0;
391  _RehashPolicy _M_rehash_policy;
392 
393  // A single bucket used when only need for 1 bucket. Especially
394  // interesting in move semantic to leave hashtable with only 1 bucket
395  // which is not allocated so that we can have those operations noexcept
396  // qualified.
397  // Note that we can't leave hashtable with 0 bucket without adding
398  // numerous checks in the code to avoid 0 modulus.
399  __node_base_ptr _M_single_bucket = nullptr;
400 
401  void
402  _M_update_bbegin()
403  {
404  if (_M_begin())
405  _M_buckets[_M_bucket_index(*_M_begin())] = &_M_before_begin;
406  }
407 
408  void
409  _M_update_bbegin(__node_ptr __n)
410  {
411  _M_before_begin._M_nxt = __n;
412  _M_update_bbegin();
413  }
414 
415  bool
416  _M_uses_single_bucket(__buckets_ptr __bkts) const
417  { return __builtin_expect(__bkts == &_M_single_bucket, false); }
418 
419  bool
420  _M_uses_single_bucket() const
421  { return _M_uses_single_bucket(_M_buckets); }
422 
423  static constexpr size_t
424  __small_size_threshold() noexcept
425  {
426  return
427  __detail::_Hashtable_hash_traits<_Hash>::__small_size_threshold();
428  }
429 
430  __hashtable_alloc&
431  _M_base_alloc() { return *this; }
432 
433  __buckets_ptr
434  _M_allocate_buckets(size_type __bkt_count)
435  {
436  if (__builtin_expect(__bkt_count == 1, false))
437  {
438  _M_single_bucket = nullptr;
439  return &_M_single_bucket;
440  }
441 
442  return __hashtable_alloc::_M_allocate_buckets(__bkt_count);
443  }
444 
445  void
446  _M_deallocate_buckets(__buckets_ptr __bkts, size_type __bkt_count)
447  {
448  if (_M_uses_single_bucket(__bkts))
449  return;
450 
451  __hashtable_alloc::_M_deallocate_buckets(__bkts, __bkt_count);
452  }
453 
454  void
455  _M_deallocate_buckets()
456  { _M_deallocate_buckets(_M_buckets, _M_bucket_count); }
457 
458  // Gets bucket begin, deals with the fact that non-empty buckets contain
459  // their before begin node.
460  __node_ptr
461  _M_bucket_begin(size_type __bkt) const;
462 
463  __node_ptr
464  _M_begin() const
465  { return static_cast<__node_ptr>(_M_before_begin._M_nxt); }
466 
467  // Assign *this using another _Hashtable instance. Whether elements
468  // are copied or moved depends on the _Ht reference.
469  template<typename _Ht>
470  void
471  _M_assign_elements(_Ht&&);
472 
473  template<typename _Ht, typename _NodeGenerator>
474  void
475  _M_assign(_Ht&&, const _NodeGenerator&);
476 
477  void
478  _M_move_assign(_Hashtable&&, true_type);
479 
480  void
481  _M_move_assign(_Hashtable&&, false_type);
482 
483  void
484  _M_reset() noexcept;
485 
486  _Hashtable(const _Hash& __h, const _Equal& __eq,
487  const allocator_type& __a)
488  : __hashtable_base(__h, __eq),
489  __hashtable_alloc(__node_alloc_type(__a)),
490  __enable_default_ctor(_Enable_default_constructor_tag{})
491  { }
492 
493  template<bool _No_realloc = true>
494  static constexpr bool
495  _S_nothrow_move()
496  {
497 #if __cplusplus <= 201402L
498  return __and_<__bool_constant<_No_realloc>,
499  is_nothrow_copy_constructible<_Hash>,
500  is_nothrow_copy_constructible<_Equal>>::value;
501 #else
502  if constexpr (_No_realloc)
503  if constexpr (is_nothrow_copy_constructible<_Hash>())
504  return is_nothrow_copy_constructible<_Equal>();
505  return false;
506 #endif
507  }
508 
509  _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
510  true_type /* alloc always equal */)
511  noexcept(_S_nothrow_move());
512 
513  _Hashtable(_Hashtable&&, __node_alloc_type&&,
514  false_type /* alloc always equal */);
515 
516  template<typename _InputIterator>
517  _Hashtable(_InputIterator __first, _InputIterator __last,
518  size_type __bkt_count_hint,
519  const _Hash&, const _Equal&, const allocator_type&,
520  true_type __uks);
521 
522  template<typename _InputIterator>
523  _Hashtable(_InputIterator __first, _InputIterator __last,
524  size_type __bkt_count_hint,
525  const _Hash&, const _Equal&, const allocator_type&,
526  false_type __uks);
527 
528  public:
529  // Constructor, destructor, assignment, swap
530  _Hashtable() = default;
531 
532  _Hashtable(const _Hashtable&);
533 
534  _Hashtable(const _Hashtable&, const allocator_type&);
535 
536  explicit
537  _Hashtable(size_type __bkt_count_hint,
538  const _Hash& __hf = _Hash(),
539  const key_equal& __eql = key_equal(),
540  const allocator_type& __a = allocator_type());
541 
542  // Use delegating constructors.
543  _Hashtable(_Hashtable&& __ht)
544  noexcept(_S_nothrow_move())
545  : _Hashtable(std::move(__ht), std::move(__ht._M_node_allocator()),
546  true_type{})
547  { }
548 
549  _Hashtable(_Hashtable&& __ht, const allocator_type& __a)
550  noexcept(_S_nothrow_move<__node_alloc_traits::_S_always_equal()>())
551  : _Hashtable(std::move(__ht), __node_alloc_type(__a),
552  typename __node_alloc_traits::is_always_equal{})
553  { }
554 
555  explicit
556  _Hashtable(const allocator_type& __a)
557  : __hashtable_alloc(__node_alloc_type(__a)),
558  __enable_default_ctor(_Enable_default_constructor_tag{})
559  { }
560 
561  template<typename _InputIterator>
562  _Hashtable(_InputIterator __f, _InputIterator __l,
563  size_type __bkt_count_hint = 0,
564  const _Hash& __hf = _Hash(),
565  const key_equal& __eql = key_equal(),
566  const allocator_type& __a = allocator_type())
567  : _Hashtable(__f, __l, __bkt_count_hint, __hf, __eql, __a,
568  __unique_keys{})
569  { }
570 
571  _Hashtable(initializer_list<value_type> __l,
572  size_type __bkt_count_hint = 0,
573  const _Hash& __hf = _Hash(),
574  const key_equal& __eql = key_equal(),
575  const allocator_type& __a = allocator_type())
576  : _Hashtable(__l.begin(), __l.end(), __bkt_count_hint,
577  __hf, __eql, __a, __unique_keys{})
578  { }
579 
580  _Hashtable&
581  operator=(const _Hashtable& __ht);
582 
583  _Hashtable&
584  operator=(_Hashtable&& __ht)
585  noexcept(__node_alloc_traits::_S_nothrow_move()
586  && is_nothrow_move_assignable<_Hash>::value
587  && is_nothrow_move_assignable<_Equal>::value)
588  {
589  constexpr bool __move_storage =
590  __node_alloc_traits::_S_propagate_on_move_assign()
591  || __node_alloc_traits::_S_always_equal();
592  _M_move_assign(std::move(__ht), __bool_constant<__move_storage>());
593  return *this;
594  }
595 
596  _Hashtable&
597  operator=(initializer_list<value_type> __l)
598  {
599  __reuse_or_alloc_node_gen_t __roan(_M_begin(), *this);
600  _M_before_begin._M_nxt = nullptr;
601  clear();
602 
603  // We consider that all elements of __l are going to be inserted.
604  auto __l_bkt_count = _M_rehash_policy._M_bkt_for_elements(__l.size());
605 
606  // Do not shrink to keep potential user reservation.
607  if (_M_bucket_count < __l_bkt_count)
608  rehash(__l_bkt_count);
609 
610  this->_M_insert_range(__l.begin(), __l.end(), __roan, __unique_keys{});
611  return *this;
612  }
613 
614  ~_Hashtable() noexcept;
615 
616  void
617  swap(_Hashtable&)
618  noexcept(__and_<__is_nothrow_swappable<_Hash>,
619  __is_nothrow_swappable<_Equal>>::value);
620 
621  // Basic container operations
622  iterator
623  begin() noexcept
624  { return iterator(_M_begin()); }
625 
626  const_iterator
627  begin() const noexcept
628  { return const_iterator(_M_begin()); }
629 
630  iterator
631  end() noexcept
632  { return iterator(nullptr); }
633 
634  const_iterator
635  end() const noexcept
636  { return const_iterator(nullptr); }
637 
638  const_iterator
639  cbegin() const noexcept
640  { return const_iterator(_M_begin()); }
641 
642  const_iterator
643  cend() const noexcept
644  { return const_iterator(nullptr); }
645 
646  size_type
647  size() const noexcept
648  { return _M_element_count; }
649 
650  _GLIBCXX_NODISCARD bool
651  empty() const noexcept
652  { return size() == 0; }
653 
654  allocator_type
655  get_allocator() const noexcept
656  { return allocator_type(this->_M_node_allocator()); }
657 
658  size_type
659  max_size() const noexcept
660  { return __node_alloc_traits::max_size(this->_M_node_allocator()); }
661 
662  // Observers
663  key_equal
664  key_eq() const
665  { return this->_M_eq(); }
666 
667  // hash_function, if present, comes from _Hash_code_base.
668 
669  // Bucket operations
670  size_type
671  bucket_count() const noexcept
672  { return _M_bucket_count; }
673 
674  size_type
675  max_bucket_count() const noexcept
676  { return max_size(); }
677 
678  size_type
679  bucket_size(size_type __bkt) const
680  { return std::distance(begin(__bkt), end(__bkt)); }
681 
682  size_type
683  bucket(const key_type& __k) const
684  { return _M_bucket_index(this->_M_hash_code(__k)); }
685 
686  local_iterator
687  begin(size_type __bkt)
688  {
689  return local_iterator(*this, _M_bucket_begin(__bkt),
690  __bkt, _M_bucket_count);
691  }
692 
693  local_iterator
694  end(size_type __bkt)
695  { return local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
696 
697  const_local_iterator
698  begin(size_type __bkt) const
699  {
700  return const_local_iterator(*this, _M_bucket_begin(__bkt),
701  __bkt, _M_bucket_count);
702  }
703 
704  const_local_iterator
705  end(size_type __bkt) const
706  { return const_local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
707 
708  // DR 691.
709  const_local_iterator
710  cbegin(size_type __bkt) const
711  {
712  return const_local_iterator(*this, _M_bucket_begin(__bkt),
713  __bkt, _M_bucket_count);
714  }
715 
716  const_local_iterator
717  cend(size_type __bkt) const
718  { return const_local_iterator(*this, nullptr, __bkt, _M_bucket_count); }
719 
720  float
721  load_factor() const noexcept
722  {
723  return static_cast<float>(size()) / static_cast<float>(bucket_count());
724  }
725 
726  // max_load_factor, if present, comes from _Rehash_base.
727 
728  // Generalization of max_load_factor. Extension, not found in
729  // TR1. Only useful if _RehashPolicy is something other than
730  // the default.
731  const _RehashPolicy&
732  __rehash_policy() const
733  { return _M_rehash_policy; }
734 
735  void
736  __rehash_policy(const _RehashPolicy& __pol)
737  { _M_rehash_policy = __pol; }
738 
739  // Lookup.
740  iterator
741  find(const key_type& __k);
742 
743  const_iterator
744  find(const key_type& __k) const;
745 
746  size_type
747  count(const key_type& __k) const;
748 
750  equal_range(const key_type& __k);
751 
753  equal_range(const key_type& __k) const;
754 
755 #if __cplusplus >= 202002L
756 #define __cpp_lib_generic_unordered_lookup 201811L
757 
758  template<typename _Kt,
759  typename = __has_is_transparent_t<_Hash, _Kt>,
760  typename = __has_is_transparent_t<_Equal, _Kt>>
761  iterator
762  _M_find_tr(const _Kt& __k);
763 
764  template<typename _Kt,
765  typename = __has_is_transparent_t<_Hash, _Kt>,
766  typename = __has_is_transparent_t<_Equal, _Kt>>
767  const_iterator
768  _M_find_tr(const _Kt& __k) const;
769 
770  template<typename _Kt,
771  typename = __has_is_transparent_t<_Hash, _Kt>,
772  typename = __has_is_transparent_t<_Equal, _Kt>>
773  size_type
774  _M_count_tr(const _Kt& __k) const;
775 
776  template<typename _Kt,
777  typename = __has_is_transparent_t<_Hash, _Kt>,
778  typename = __has_is_transparent_t<_Equal, _Kt>>
779  pair<iterator, iterator>
780  _M_equal_range_tr(const _Kt& __k);
781 
782  template<typename _Kt,
783  typename = __has_is_transparent_t<_Hash, _Kt>,
784  typename = __has_is_transparent_t<_Equal, _Kt>>
785  pair<const_iterator, const_iterator>
786  _M_equal_range_tr(const _Kt& __k) const;
787 #endif // C++20
788 
789  private:
790  // Bucket index computation helpers.
791  size_type
792  _M_bucket_index(const __node_value_type& __n) const noexcept
793  { return __hash_code_base::_M_bucket_index(__n, _M_bucket_count); }
794 
795  size_type
796  _M_bucket_index(__hash_code __c) const
797  { return __hash_code_base::_M_bucket_index(__c, _M_bucket_count); }
798 
799  __node_base_ptr
800  _M_find_before_node(const key_type&);
801 
802  // Find and insert helper functions and types
803  // Find the node before the one matching the criteria.
804  __node_base_ptr
805  _M_find_before_node(size_type, const key_type&, __hash_code) const;
806 
807  template<typename _Kt>
808  __node_base_ptr
809  _M_find_before_node_tr(size_type, const _Kt&, __hash_code) const;
810 
811  __node_ptr
812  _M_find_node(size_type __bkt, const key_type& __key,
813  __hash_code __c) const
814  {
815  __node_base_ptr __before_n = _M_find_before_node(__bkt, __key, __c);
816  if (__before_n)
817  return static_cast<__node_ptr>(__before_n->_M_nxt);
818  return nullptr;
819  }
820 
821  template<typename _Kt>
822  __node_ptr
823  _M_find_node_tr(size_type __bkt, const _Kt& __key,
824  __hash_code __c) const
825  {
826  auto __before_n = _M_find_before_node_tr(__bkt, __key, __c);
827  if (__before_n)
828  return static_cast<__node_ptr>(__before_n->_M_nxt);
829  return nullptr;
830  }
831 
832  // Insert a node at the beginning of a bucket.
833  void
834  _M_insert_bucket_begin(size_type, __node_ptr);
835 
836  // Remove the bucket first node
837  void
838  _M_remove_bucket_begin(size_type __bkt, __node_ptr __next_n,
839  size_type __next_bkt);
840 
841  // Get the node before __n in the bucket __bkt
842  __node_base_ptr
843  _M_get_previous_node(size_type __bkt, __node_ptr __n);
844 
845  pair<const_iterator, __hash_code>
846  _M_compute_hash_code(const_iterator __hint, const key_type& __k) const;
847 
848  // Insert node __n with hash code __code, in bucket __bkt if no
849  // rehash (assumes no element with same key already present).
850  // Takes ownership of __n if insertion succeeds, throws otherwise.
851  iterator
852  _M_insert_unique_node(size_type __bkt, __hash_code,
853  __node_ptr __n, size_type __n_elt = 1);
854 
855  // Insert node __n with key __k and hash code __code.
856  // Takes ownership of __n if insertion succeeds, throws otherwise.
857  iterator
858  _M_insert_multi_node(__node_ptr __hint,
859  __hash_code __code, __node_ptr __n);
860 
861  template<typename... _Args>
863  _M_emplace(true_type __uks, _Args&&... __args);
864 
865  template<typename... _Args>
866  iterator
867  _M_emplace(false_type __uks, _Args&&... __args)
868  { return _M_emplace(cend(), __uks, std::forward<_Args>(__args)...); }
869 
870  // Emplace with hint, useless when keys are unique.
871  template<typename... _Args>
872  iterator
873  _M_emplace(const_iterator, true_type __uks, _Args&&... __args)
874  { return _M_emplace(__uks, std::forward<_Args>(__args)...).first; }
875 
876  template<typename... _Args>
877  iterator
878  _M_emplace(const_iterator, false_type __uks, _Args&&... __args);
879 
880  template<typename _Kt, typename _Arg, typename _NodeGenerator>
882  _M_insert_unique(_Kt&&, _Arg&&, const _NodeGenerator&);
883 
884  template<typename _Kt>
885  static __conditional_t<
886  __and_<__is_nothrow_invocable<_Hash&, const key_type&>,
887  __not_<__is_nothrow_invocable<_Hash&, _Kt>>>::value,
888  key_type, _Kt&&>
889  _S_forward_key(_Kt&& __k)
890  { return std::forward<_Kt>(__k); }
891 
892  static const key_type&
893  _S_forward_key(const key_type& __k)
894  { return __k; }
895 
896  static key_type&&
897  _S_forward_key(key_type&& __k)
898  { return std::move(__k); }
899 
900  template<typename _Arg, typename _NodeGenerator>
902  _M_insert_unique_aux(_Arg&& __arg, const _NodeGenerator& __node_gen)
903  {
904  return _M_insert_unique(
905  _S_forward_key(_ExtractKey{}(std::forward<_Arg>(__arg))),
906  std::forward<_Arg>(__arg), __node_gen);
907  }
908 
909  template<typename _Arg, typename _NodeGenerator>
911  _M_insert(_Arg&& __arg, const _NodeGenerator& __node_gen,
912  true_type /* __uks */)
913  {
914  using __to_value
915  = __detail::_ConvertToValueType<_ExtractKey, value_type>;
916  return _M_insert_unique_aux(
917  __to_value{}(std::forward<_Arg>(__arg)), __node_gen);
918  }
919 
920  template<typename _Arg, typename _NodeGenerator>
921  iterator
922  _M_insert(_Arg&& __arg, const _NodeGenerator& __node_gen,
923  false_type __uks)
924  {
925  using __to_value
926  = __detail::_ConvertToValueType<_ExtractKey, value_type>;
927  return _M_insert(cend(),
928  __to_value{}(std::forward<_Arg>(__arg)), __node_gen, __uks);
929  }
930 
931  // Insert with hint, not used when keys are unique.
932  template<typename _Arg, typename _NodeGenerator>
933  iterator
934  _M_insert(const_iterator, _Arg&& __arg,
935  const _NodeGenerator& __node_gen, true_type __uks)
936  {
937  return
938  _M_insert(std::forward<_Arg>(__arg), __node_gen, __uks).first;
939  }
940 
941  // Insert with hint when keys are not unique.
942  template<typename _Arg, typename _NodeGenerator>
943  iterator
944  _M_insert(const_iterator, _Arg&&,
945  const _NodeGenerator&, false_type __uks);
946 
947  size_type
948  _M_erase(true_type __uks, const key_type&);
949 
950  size_type
951  _M_erase(false_type __uks, const key_type&);
952 
953  iterator
954  _M_erase(size_type __bkt, __node_base_ptr __prev_n, __node_ptr __n);
955 
956  public:
957  // Emplace
958  template<typename... _Args>
959  __ireturn_type
960  emplace(_Args&&... __args)
961  { return _M_emplace(__unique_keys{}, std::forward<_Args>(__args)...); }
962 
963  template<typename... _Args>
964  iterator
965  emplace_hint(const_iterator __hint, _Args&&... __args)
966  {
967  return _M_emplace(__hint, __unique_keys{},
968  std::forward<_Args>(__args)...);
969  }
970 
971  // Insert member functions via inheritance.
972 
973  // Erase
974  iterator
975  erase(const_iterator);
976 
977  // LWG 2059.
978  iterator
979  erase(iterator __it)
980  { return erase(const_iterator(__it)); }
981 
982  size_type
983  erase(const key_type& __k)
984  { return _M_erase(__unique_keys{}, __k); }
985 
986  iterator
987  erase(const_iterator, const_iterator);
988 
989  void
990  clear() noexcept;
991 
992  // Set number of buckets keeping it appropriate for container's number
993  // of elements.
994  void rehash(size_type __bkt_count);
995 
996  // DR 1189.
997  // reserve, if present, comes from _Rehash_base.
998 
999 #if __cplusplus > 201402L
1000  /// Re-insert an extracted node into a container with unique keys.
1001  insert_return_type
1002  _M_reinsert_node(node_type&& __nh)
1003  {
1004  insert_return_type __ret;
1005  if (__nh.empty())
1006  __ret.position = end();
1007  else
1008  {
1009  __glibcxx_assert(get_allocator() == __nh.get_allocator());
1010 
1011  const key_type& __k = __nh._M_key();
1012  __hash_code __code = this->_M_hash_code(__k);
1013  size_type __bkt = _M_bucket_index(__code);
1014  if (__node_ptr __n = _M_find_node(__bkt, __k, __code))
1015  {
1016  __ret.node = std::move(__nh);
1017  __ret.position = iterator(__n);
1018  __ret.inserted = false;
1019  }
1020  else
1021  {
1022  __ret.position
1023  = _M_insert_unique_node(__bkt, __code, __nh._M_ptr);
1024  __nh._M_ptr = nullptr;
1025  __ret.inserted = true;
1026  }
1027  }
1028  return __ret;
1029  }
1030 
1031  /// Re-insert an extracted node into a container with equivalent keys.
1032  iterator
1033  _M_reinsert_node_multi(const_iterator __hint, node_type&& __nh)
1034  {
1035  if (__nh.empty())
1036  return end();
1037 
1038  __glibcxx_assert(get_allocator() == __nh.get_allocator());
1039 
1040  const key_type& __k = __nh._M_key();
1041  auto __code = this->_M_hash_code(__k);
1042  auto __ret
1043  = _M_insert_multi_node(__hint._M_cur, __code, __nh._M_ptr);
1044  __nh._M_ptr = nullptr;
1045  return __ret;
1046  }
1047 
1048  private:
1049  node_type
1050  _M_extract_node(size_t __bkt, __node_base_ptr __prev_n)
1051  {
1052  __node_ptr __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
1053  if (__prev_n == _M_buckets[__bkt])
1054  _M_remove_bucket_begin(__bkt, __n->_M_next(),
1055  __n->_M_nxt ? _M_bucket_index(*__n->_M_next()) : 0);
1056  else if (__n->_M_nxt)
1057  {
1058  size_type __next_bkt = _M_bucket_index(*__n->_M_next());
1059  if (__next_bkt != __bkt)
1060  _M_buckets[__next_bkt] = __prev_n;
1061  }
1062 
1063  __prev_n->_M_nxt = __n->_M_nxt;
1064  __n->_M_nxt = nullptr;
1065  --_M_element_count;
1066  return { __n, this->_M_node_allocator() };
1067  }
1068 
1069  public:
1070  // Extract a node.
1071  node_type
1072  extract(const_iterator __pos)
1073  {
1074  size_t __bkt = _M_bucket_index(*__pos._M_cur);
1075  return _M_extract_node(__bkt,
1076  _M_get_previous_node(__bkt, __pos._M_cur));
1077  }
1078 
1079  /// Extract a node.
1080  node_type
1081  extract(const _Key& __k)
1082  {
1083  node_type __nh;
1084  __hash_code __code = this->_M_hash_code(__k);
1085  std::size_t __bkt = _M_bucket_index(__code);
1086  if (__node_base_ptr __prev_node = _M_find_before_node(__bkt, __k, __code))
1087  __nh = _M_extract_node(__bkt, __prev_node);
1088  return __nh;
1089  }
1090 
1091  /// Merge from a compatible container into one with unique keys.
1092  template<typename _Compatible_Hashtable>
1093  void
1094  _M_merge_unique(_Compatible_Hashtable& __src)
1095  {
1096  static_assert(is_same_v<typename _Compatible_Hashtable::node_type,
1097  node_type>, "Node types are compatible");
1098  __glibcxx_assert(get_allocator() == __src.get_allocator());
1099 
1100  auto __n_elt = __src.size();
1101  for (auto __i = __src.cbegin(), __end = __src.cend(); __i != __end;)
1102  {
1103  auto __pos = __i++;
1104  const key_type& __k = _ExtractKey{}(*__pos);
1105  __hash_code __code
1106  = this->_M_hash_code(__src.hash_function(), *__pos._M_cur);
1107  size_type __bkt = _M_bucket_index(__code);
1108  if (_M_find_node(__bkt, __k, __code) == nullptr)
1109  {
1110  auto __nh = __src.extract(__pos);
1111  _M_insert_unique_node(__bkt, __code, __nh._M_ptr, __n_elt);
1112  __nh._M_ptr = nullptr;
1113  __n_elt = 1;
1114  }
1115  else if (__n_elt != 1)
1116  --__n_elt;
1117  }
1118  }
1119 
1120  /// Merge from a compatible container into one with equivalent keys.
1121  template<typename _Compatible_Hashtable>
1122  void
1123  _M_merge_multi(_Compatible_Hashtable& __src)
1124  {
1125  static_assert(is_same_v<typename _Compatible_Hashtable::node_type,
1126  node_type>, "Node types are compatible");
1127  __glibcxx_assert(get_allocator() == __src.get_allocator());
1128 
1129  __node_ptr __hint = nullptr;
1130  this->reserve(size() + __src.size());
1131  for (auto __i = __src.cbegin(), __end = __src.cend(); __i != __end;)
1132  {
1133  auto __pos = __i++;
1134  __hash_code __code
1135  = this->_M_hash_code(__src.hash_function(), *__pos._M_cur);
1136  auto __nh = __src.extract(__pos);
1137  __hint = _M_insert_multi_node(__hint, __code, __nh._M_ptr)._M_cur;
1138  __nh._M_ptr = nullptr;
1139  }
1140  }
1141 #endif // C++17
1142 
1143  private:
1144  // Helper rehash method used when keys are unique.
1145  void _M_rehash_aux(size_type __bkt_count, true_type __uks);
1146 
1147  // Helper rehash method used when keys can be non-unique.
1148  void _M_rehash_aux(size_type __bkt_count, false_type __uks);
1149 
1150  // Unconditionally change size of bucket array to n, restore
1151  // hash policy state to __state on exception.
1152  void _M_rehash(size_type __bkt_count, const __rehash_state& __state);
1153  };
1154 
1155  // Definitions of class template _Hashtable's out-of-line member functions.
1156  template<typename _Key, typename _Value, typename _Alloc,
1157  typename _ExtractKey, typename _Equal,
1158  typename _Hash, typename _RangeHash, typename _Unused,
1159  typename _RehashPolicy, typename _Traits>
1160  auto
1161  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1162  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1163  _M_bucket_begin(size_type __bkt) const
1164  -> __node_ptr
1165  {
1166  __node_base_ptr __n = _M_buckets[__bkt];
1167  return __n ? static_cast<__node_ptr>(__n->_M_nxt) : nullptr;
1168  }
1169 
1170  template<typename _Key, typename _Value, typename _Alloc,
1171  typename _ExtractKey, typename _Equal,
1172  typename _Hash, typename _RangeHash, typename _Unused,
1173  typename _RehashPolicy, typename _Traits>
1174  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1175  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1176  _Hashtable(size_type __bkt_count_hint,
1177  const _Hash& __h, const _Equal& __eq, const allocator_type& __a)
1178  : _Hashtable(__h, __eq, __a)
1179  {
1180  auto __bkt_count = _M_rehash_policy._M_next_bkt(__bkt_count_hint);
1181  if (__bkt_count > _M_bucket_count)
1182  {
1183  _M_buckets = _M_allocate_buckets(__bkt_count);
1184  _M_bucket_count = __bkt_count;
1185  }
1186  }
1187 
1188  template<typename _Key, typename _Value, typename _Alloc,
1189  typename _ExtractKey, typename _Equal,
1190  typename _Hash, typename _RangeHash, typename _Unused,
1191  typename _RehashPolicy, typename _Traits>
1192  template<typename _InputIterator>
1193  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1194  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1195  _Hashtable(_InputIterator __f, _InputIterator __l,
1196  size_type __bkt_count_hint,
1197  const _Hash& __h, const _Equal& __eq,
1198  const allocator_type& __a, true_type /* __uks */)
1199  : _Hashtable(__bkt_count_hint, __h, __eq, __a)
1200  { this->insert(__f, __l); }
1201 
1202  template<typename _Key, typename _Value, typename _Alloc,
1203  typename _ExtractKey, typename _Equal,
1204  typename _Hash, typename _RangeHash, typename _Unused,
1205  typename _RehashPolicy, typename _Traits>
1206  template<typename _InputIterator>
1207  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1208  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1209  _Hashtable(_InputIterator __f, _InputIterator __l,
1210  size_type __bkt_count_hint,
1211  const _Hash& __h, const _Equal& __eq,
1212  const allocator_type& __a, false_type __uks)
1213  : _Hashtable(__h, __eq, __a)
1214  {
1215  auto __nb_elems = __detail::__distance_fw(__f, __l);
1216  auto __bkt_count =
1217  _M_rehash_policy._M_next_bkt(
1218  std::max(_M_rehash_policy._M_bkt_for_elements(__nb_elems),
1219  __bkt_count_hint));
1220 
1221  if (__bkt_count > _M_bucket_count)
1222  {
1223  _M_buckets = _M_allocate_buckets(__bkt_count);
1224  _M_bucket_count = __bkt_count;
1225  }
1226 
1227  __alloc_node_gen_t __node_gen(*this);
1228  for (; __f != __l; ++__f)
1229  _M_insert(*__f, __node_gen, __uks);
1230  }
1231 
1232  template<typename _Key, typename _Value, typename _Alloc,
1233  typename _ExtractKey, typename _Equal,
1234  typename _Hash, typename _RangeHash, typename _Unused,
1235  typename _RehashPolicy, typename _Traits>
1236  auto
1237  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1238  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1239  operator=(const _Hashtable& __ht)
1240  -> _Hashtable&
1241  {
1242  if (&__ht == this)
1243  return *this;
1244 
1245  if (__node_alloc_traits::_S_propagate_on_copy_assign())
1246  {
1247  auto& __this_alloc = this->_M_node_allocator();
1248  auto& __that_alloc = __ht._M_node_allocator();
1249  if (!__node_alloc_traits::_S_always_equal()
1250  && __this_alloc != __that_alloc)
1251  {
1252  // Replacement allocator cannot free existing storage.
1253  this->_M_deallocate_nodes(_M_begin());
1254  _M_before_begin._M_nxt = nullptr;
1255  _M_deallocate_buckets();
1256  _M_buckets = nullptr;
1257  std::__alloc_on_copy(__this_alloc, __that_alloc);
1258  __hashtable_base::operator=(__ht);
1259  _M_bucket_count = __ht._M_bucket_count;
1260  _M_element_count = __ht._M_element_count;
1261  _M_rehash_policy = __ht._M_rehash_policy;
1262  __alloc_node_gen_t __alloc_node_gen(*this);
1263  __try
1264  {
1265  _M_assign(__ht, __alloc_node_gen);
1266  }
1267  __catch(...)
1268  {
1269  // _M_assign took care of deallocating all memory. Now we
1270  // must make sure this instance remains in a usable state.
1271  _M_reset();
1272  __throw_exception_again;
1273  }
1274  return *this;
1275  }
1276  std::__alloc_on_copy(__this_alloc, __that_alloc);
1277  }
1278 
1279  // Reuse allocated buckets and nodes.
1280  _M_assign_elements(__ht);
1281  return *this;
1282  }
1283 
1284  template<typename _Key, typename _Value, typename _Alloc,
1285  typename _ExtractKey, typename _Equal,
1286  typename _Hash, typename _RangeHash, typename _Unused,
1287  typename _RehashPolicy, typename _Traits>
1288  template<typename _Ht>
1289  void
1290  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1291  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1292  _M_assign_elements(_Ht&& __ht)
1293  {
1294  __buckets_ptr __former_buckets = nullptr;
1295  std::size_t __former_bucket_count = _M_bucket_count;
1296  const __rehash_state& __former_state = _M_rehash_policy._M_state();
1297 
1298  if (_M_bucket_count != __ht._M_bucket_count)
1299  {
1300  __former_buckets = _M_buckets;
1301  _M_buckets = _M_allocate_buckets(__ht._M_bucket_count);
1302  _M_bucket_count = __ht._M_bucket_count;
1303  }
1304  else
1305  __builtin_memset(_M_buckets, 0,
1306  _M_bucket_count * sizeof(__node_base_ptr));
1307 
1308  __try
1309  {
1310  __hashtable_base::operator=(std::forward<_Ht>(__ht));
1311  _M_element_count = __ht._M_element_count;
1312  _M_rehash_policy = __ht._M_rehash_policy;
1313  __reuse_or_alloc_node_gen_t __roan(_M_begin(), *this);
1314  _M_before_begin._M_nxt = nullptr;
1315  _M_assign(std::forward<_Ht>(__ht), __roan);
1316  if (__former_buckets)
1317  _M_deallocate_buckets(__former_buckets, __former_bucket_count);
1318  }
1319  __catch(...)
1320  {
1321  if (__former_buckets)
1322  {
1323  // Restore previous buckets.
1324  _M_deallocate_buckets();
1325  _M_rehash_policy._M_reset(__former_state);
1326  _M_buckets = __former_buckets;
1327  _M_bucket_count = __former_bucket_count;
1328  }
1329  __builtin_memset(_M_buckets, 0,
1330  _M_bucket_count * sizeof(__node_base_ptr));
1331  __throw_exception_again;
1332  }
1333  }
1334 
1335  template<typename _Key, typename _Value, typename _Alloc,
1336  typename _ExtractKey, typename _Equal,
1337  typename _Hash, typename _RangeHash, typename _Unused,
1338  typename _RehashPolicy, typename _Traits>
1339  template<typename _Ht, typename _NodeGenerator>
1340  void
1341  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1342  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1343  _M_assign(_Ht&& __ht, const _NodeGenerator& __node_gen)
1344  {
1345  __buckets_ptr __buckets = nullptr;
1346  if (!_M_buckets)
1347  _M_buckets = __buckets = _M_allocate_buckets(_M_bucket_count);
1348 
1349  __try
1350  {
1351  if (!__ht._M_before_begin._M_nxt)
1352  return;
1353 
1354  // First deal with the special first node pointed to by
1355  // _M_before_begin.
1356  __node_ptr __ht_n = __ht._M_begin();
1357  __node_ptr __this_n
1358  = __node_gen(__fwd_value_for<_Ht>(__ht_n->_M_v()));
1359  this->_M_copy_code(*__this_n, *__ht_n);
1360  _M_update_bbegin(__this_n);
1361 
1362  // Then deal with other nodes.
1363  __node_ptr __prev_n = __this_n;
1364  for (__ht_n = __ht_n->_M_next(); __ht_n; __ht_n = __ht_n->_M_next())
1365  {
1366  __this_n = __node_gen(__fwd_value_for<_Ht>(__ht_n->_M_v()));
1367  __prev_n->_M_nxt = __this_n;
1368  this->_M_copy_code(*__this_n, *__ht_n);
1369  size_type __bkt = _M_bucket_index(*__this_n);
1370  if (!_M_buckets[__bkt])
1371  _M_buckets[__bkt] = __prev_n;
1372  __prev_n = __this_n;
1373  }
1374  }
1375  __catch(...)
1376  {
1377  clear();
1378  if (__buckets)
1379  _M_deallocate_buckets();
1380  __throw_exception_again;
1381  }
1382  }
1383 
1384  template<typename _Key, typename _Value, typename _Alloc,
1385  typename _ExtractKey, typename _Equal,
1386  typename _Hash, typename _RangeHash, typename _Unused,
1387  typename _RehashPolicy, typename _Traits>
1388  void
1389  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1390  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1391  _M_reset() noexcept
1392  {
1393  _M_rehash_policy._M_reset();
1394  _M_bucket_count = 1;
1395  _M_single_bucket = nullptr;
1396  _M_buckets = &_M_single_bucket;
1397  _M_before_begin._M_nxt = nullptr;
1398  _M_element_count = 0;
1399  }
1400 
1401  template<typename _Key, typename _Value, typename _Alloc,
1402  typename _ExtractKey, typename _Equal,
1403  typename _Hash, typename _RangeHash, typename _Unused,
1404  typename _RehashPolicy, typename _Traits>
1405  void
1406  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1407  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1408  _M_move_assign(_Hashtable&& __ht, true_type)
1409  {
1410  if (__builtin_expect(std::__addressof(__ht) == this, false))
1411  return;
1412 
1413  this->_M_deallocate_nodes(_M_begin());
1414  _M_deallocate_buckets();
1415  __hashtable_base::operator=(std::move(__ht));
1416  _M_rehash_policy = __ht._M_rehash_policy;
1417  if (!__ht._M_uses_single_bucket())
1418  _M_buckets = __ht._M_buckets;
1419  else
1420  {
1421  _M_buckets = &_M_single_bucket;
1422  _M_single_bucket = __ht._M_single_bucket;
1423  }
1424 
1425  _M_bucket_count = __ht._M_bucket_count;
1426  _M_before_begin._M_nxt = __ht._M_before_begin._M_nxt;
1427  _M_element_count = __ht._M_element_count;
1428  std::__alloc_on_move(this->_M_node_allocator(), __ht._M_node_allocator());
1429 
1430  // Fix bucket containing the _M_before_begin pointer that can't be moved.
1431  _M_update_bbegin();
1432  __ht._M_reset();
1433  }
1434 
1435  template<typename _Key, typename _Value, typename _Alloc,
1436  typename _ExtractKey, typename _Equal,
1437  typename _Hash, typename _RangeHash, typename _Unused,
1438  typename _RehashPolicy, typename _Traits>
1439  void
1440  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1441  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1442  _M_move_assign(_Hashtable&& __ht, false_type)
1443  {
1444  if (__ht._M_node_allocator() == this->_M_node_allocator())
1445  _M_move_assign(std::move(__ht), true_type{});
1446  else
1447  {
1448  // Can't move memory, move elements then.
1449  _M_assign_elements(std::move(__ht));
1450  __ht.clear();
1451  }
1452  }
1453 
1454  template<typename _Key, typename _Value, typename _Alloc,
1455  typename _ExtractKey, typename _Equal,
1456  typename _Hash, typename _RangeHash, typename _Unused,
1457  typename _RehashPolicy, typename _Traits>
1458  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1459  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1460  _Hashtable(const _Hashtable& __ht)
1461  : __hashtable_base(__ht),
1462  __map_base(__ht),
1463  __rehash_base(__ht),
1464  __hashtable_alloc(
1465  __node_alloc_traits::_S_select_on_copy(__ht._M_node_allocator())),
1466  __enable_default_ctor(__ht),
1467  _M_buckets(nullptr),
1468  _M_bucket_count(__ht._M_bucket_count),
1469  _M_element_count(__ht._M_element_count),
1470  _M_rehash_policy(__ht._M_rehash_policy)
1471  {
1472  __alloc_node_gen_t __alloc_node_gen(*this);
1473  _M_assign(__ht, __alloc_node_gen);
1474  }
1475 
1476  template<typename _Key, typename _Value, typename _Alloc,
1477  typename _ExtractKey, typename _Equal,
1478  typename _Hash, typename _RangeHash, typename _Unused,
1479  typename _RehashPolicy, typename _Traits>
1480  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1481  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1482  _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
1483  true_type /* alloc always equal */)
1484  noexcept(_S_nothrow_move())
1485  : __hashtable_base(__ht),
1486  __map_base(__ht),
1487  __rehash_base(__ht),
1488  __hashtable_alloc(std::move(__a)),
1489  __enable_default_ctor(__ht),
1490  _M_buckets(__ht._M_buckets),
1491  _M_bucket_count(__ht._M_bucket_count),
1492  _M_before_begin(__ht._M_before_begin._M_nxt),
1493  _M_element_count(__ht._M_element_count),
1494  _M_rehash_policy(__ht._M_rehash_policy)
1495  {
1496  // Update buckets if __ht is using its single bucket.
1497  if (__ht._M_uses_single_bucket())
1498  {
1499  _M_buckets = &_M_single_bucket;
1500  _M_single_bucket = __ht._M_single_bucket;
1501  }
1502 
1503  // Fix bucket containing the _M_before_begin pointer that can't be moved.
1504  _M_update_bbegin();
1505 
1506  __ht._M_reset();
1507  }
1508 
1509  template<typename _Key, typename _Value, typename _Alloc,
1510  typename _ExtractKey, typename _Equal,
1511  typename _Hash, typename _RangeHash, typename _Unused,
1512  typename _RehashPolicy, typename _Traits>
1513  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1514  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1515  _Hashtable(const _Hashtable& __ht, const allocator_type& __a)
1516  : __hashtable_base(__ht),
1517  __map_base(__ht),
1518  __rehash_base(__ht),
1519  __hashtable_alloc(__node_alloc_type(__a)),
1520  __enable_default_ctor(__ht),
1521  _M_buckets(),
1522  _M_bucket_count(__ht._M_bucket_count),
1523  _M_element_count(__ht._M_element_count),
1524  _M_rehash_policy(__ht._M_rehash_policy)
1525  {
1526  __alloc_node_gen_t __alloc_node_gen(*this);
1527  _M_assign(__ht, __alloc_node_gen);
1528  }
1529 
1530  template<typename _Key, typename _Value, typename _Alloc,
1531  typename _ExtractKey, typename _Equal,
1532  typename _Hash, typename _RangeHash, typename _Unused,
1533  typename _RehashPolicy, typename _Traits>
1534  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1535  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1536  _Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
1537  false_type /* alloc always equal */)
1538  : __hashtable_base(__ht),
1539  __map_base(__ht),
1540  __rehash_base(__ht),
1541  __hashtable_alloc(std::move(__a)),
1542  __enable_default_ctor(__ht),
1543  _M_buckets(nullptr),
1544  _M_bucket_count(__ht._M_bucket_count),
1545  _M_element_count(__ht._M_element_count),
1546  _M_rehash_policy(__ht._M_rehash_policy)
1547  {
1548  if (__ht._M_node_allocator() == this->_M_node_allocator())
1549  {
1550  if (__ht._M_uses_single_bucket())
1551  {
1552  _M_buckets = &_M_single_bucket;
1553  _M_single_bucket = __ht._M_single_bucket;
1554  }
1555  else
1556  _M_buckets = __ht._M_buckets;
1557 
1558  // Fix bucket containing the _M_before_begin pointer that can't be
1559  // moved.
1560  _M_update_bbegin(__ht._M_begin());
1561 
1562  __ht._M_reset();
1563  }
1564  else
1565  {
1566  __alloc_node_gen_t __alloc_gen(*this);
1567 
1568  using _Fwd_Ht = __conditional_t<
1569  __move_if_noexcept_cond<value_type>::value,
1570  const _Hashtable&, _Hashtable&&>;
1571  _M_assign(std::forward<_Fwd_Ht>(__ht), __alloc_gen);
1572  __ht.clear();
1573  }
1574  }
1575 
1576  template<typename _Key, typename _Value, typename _Alloc,
1577  typename _ExtractKey, typename _Equal,
1578  typename _Hash, typename _RangeHash, typename _Unused,
1579  typename _RehashPolicy, typename _Traits>
1580  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1581  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1582  ~_Hashtable() noexcept
1583  {
1584  // Getting a bucket index from a node shall not throw because it is used
1585  // in methods (erase, swap...) that shall not throw. Need a complete
1586  // type to check this, so do it in the destructor not at class scope.
1587  static_assert(noexcept(declval<const __hash_code_base_access&>()
1588  ._M_bucket_index(declval<const __node_value_type&>(),
1589  (std::size_t)0)),
1590  "Cache the hash code or qualify your functors involved"
1591  " in hash code and bucket index computation with noexcept");
1592 
1593  clear();
1594  _M_deallocate_buckets();
1595  }
1596 
1597  template<typename _Key, typename _Value, typename _Alloc,
1598  typename _ExtractKey, typename _Equal,
1599  typename _Hash, typename _RangeHash, typename _Unused,
1600  typename _RehashPolicy, typename _Traits>
1601  void
1602  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1603  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1604  swap(_Hashtable& __x)
1605  noexcept(__and_<__is_nothrow_swappable<_Hash>,
1606  __is_nothrow_swappable<_Equal>>::value)
1607  {
1608  // The only base class with member variables is hash_code_base.
1609  // We define _Hash_code_base::_M_swap because different
1610  // specializations have different members.
1611  this->_M_swap(__x);
1612 
1613  std::__alloc_on_swap(this->_M_node_allocator(), __x._M_node_allocator());
1614  std::swap(_M_rehash_policy, __x._M_rehash_policy);
1615 
1616  // Deal properly with potentially moved instances.
1617  if (this->_M_uses_single_bucket())
1618  {
1619  if (!__x._M_uses_single_bucket())
1620  {
1621  _M_buckets = __x._M_buckets;
1622  __x._M_buckets = &__x._M_single_bucket;
1623  }
1624  }
1625  else if (__x._M_uses_single_bucket())
1626  {
1627  __x._M_buckets = _M_buckets;
1628  _M_buckets = &_M_single_bucket;
1629  }
1630  else
1631  std::swap(_M_buckets, __x._M_buckets);
1632 
1633  std::swap(_M_bucket_count, __x._M_bucket_count);
1634  std::swap(_M_before_begin._M_nxt, __x._M_before_begin._M_nxt);
1635  std::swap(_M_element_count, __x._M_element_count);
1636  std::swap(_M_single_bucket, __x._M_single_bucket);
1637 
1638  // Fix buckets containing the _M_before_begin pointers that can't be
1639  // swapped.
1640  _M_update_bbegin();
1641  __x._M_update_bbegin();
1642  }
1643 
1644  template<typename _Key, typename _Value, typename _Alloc,
1645  typename _ExtractKey, typename _Equal,
1646  typename _Hash, typename _RangeHash, typename _Unused,
1647  typename _RehashPolicy, typename _Traits>
1648  auto
1649  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1650  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1651  find(const key_type& __k)
1652  -> iterator
1653  {
1654  if (size() <= __small_size_threshold())
1655  {
1656  for (auto __it = begin(); __it != end(); ++__it)
1657  if (this->_M_key_equals(__k, *__it._M_cur))
1658  return __it;
1659  return end();
1660  }
1661 
1662  __hash_code __code = this->_M_hash_code(__k);
1663  std::size_t __bkt = _M_bucket_index(__code);
1664  return iterator(_M_find_node(__bkt, __k, __code));
1665  }
1666 
1667  template<typename _Key, typename _Value, typename _Alloc,
1668  typename _ExtractKey, typename _Equal,
1669  typename _Hash, typename _RangeHash, typename _Unused,
1670  typename _RehashPolicy, typename _Traits>
1671  auto
1672  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1673  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1674  find(const key_type& __k) const
1675  -> const_iterator
1676  {
1677  if (size() <= __small_size_threshold())
1678  {
1679  for (auto __it = begin(); __it != end(); ++__it)
1680  if (this->_M_key_equals(__k, *__it._M_cur))
1681  return __it;
1682  return end();
1683  }
1684 
1685  __hash_code __code = this->_M_hash_code(__k);
1686  std::size_t __bkt = _M_bucket_index(__code);
1687  return const_iterator(_M_find_node(__bkt, __k, __code));
1688  }
1689 
1690 #if __cplusplus > 201703L
1691  template<typename _Key, typename _Value, typename _Alloc,
1692  typename _ExtractKey, typename _Equal,
1693  typename _Hash, typename _RangeHash, typename _Unused,
1694  typename _RehashPolicy, typename _Traits>
1695  template<typename _Kt, typename, typename>
1696  auto
1697  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1698  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1699  _M_find_tr(const _Kt& __k)
1700  -> iterator
1701  {
1702  __hash_code __code = this->_M_hash_code_tr(__k);
1703  std::size_t __bkt = _M_bucket_index(__code);
1704  return iterator(_M_find_node_tr(__bkt, __k, __code));
1705  }
1706 
1707  template<typename _Key, typename _Value, typename _Alloc,
1708  typename _ExtractKey, typename _Equal,
1709  typename _Hash, typename _RangeHash, typename _Unused,
1710  typename _RehashPolicy, typename _Traits>
1711  template<typename _Kt, typename, typename>
1712  auto
1713  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1714  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1715  _M_find_tr(const _Kt& __k) const
1716  -> const_iterator
1717  {
1718  __hash_code __code = this->_M_hash_code_tr(__k);
1719  std::size_t __bkt = _M_bucket_index(__code);
1720  return const_iterator(_M_find_node_tr(__bkt, __k, __code));
1721  }
1722 #endif
1723 
1724  template<typename _Key, typename _Value, typename _Alloc,
1725  typename _ExtractKey, typename _Equal,
1726  typename _Hash, typename _RangeHash, typename _Unused,
1727  typename _RehashPolicy, typename _Traits>
1728  auto
1729  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1730  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1731  count(const key_type& __k) const
1732  -> size_type
1733  {
1734  auto __it = find(__k);
1735  if (!__it._M_cur)
1736  return 0;
1737 
1738  if (__unique_keys::value)
1739  return 1;
1740 
1741  // All equivalent values are next to each other, if we find a
1742  // non-equivalent value after an equivalent one it means that we won't
1743  // find any new equivalent value.
1744  size_type __result = 1;
1745  for (auto __ref = __it++;
1746  __it._M_cur && this->_M_node_equals(*__ref._M_cur, *__it._M_cur);
1747  ++__it)
1748  ++__result;
1749 
1750  return __result;
1751  }
1752 
1753 #if __cplusplus > 201703L
1754  template<typename _Key, typename _Value, typename _Alloc,
1755  typename _ExtractKey, typename _Equal,
1756  typename _Hash, typename _RangeHash, typename _Unused,
1757  typename _RehashPolicy, typename _Traits>
1758  template<typename _Kt, typename, typename>
1759  auto
1760  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1761  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1762  _M_count_tr(const _Kt& __k) const
1763  -> size_type
1764  {
1765  __hash_code __code = this->_M_hash_code_tr(__k);
1766  std::size_t __bkt = _M_bucket_index(__code);
1767  auto __n = _M_find_node_tr(__bkt, __k, __code);
1768  if (!__n)
1769  return 0;
1770 
1771  // All equivalent values are next to each other, if we find a
1772  // non-equivalent value after an equivalent one it means that we won't
1773  // find any new equivalent value.
1774  iterator __it(__n);
1775  size_type __result = 1;
1776  for (++__it;
1777  __it._M_cur && this->_M_equals_tr(__k, __code, *__it._M_cur);
1778  ++__it)
1779  ++__result;
1780 
1781  return __result;
1782  }
1783 #endif
1784 
1785  template<typename _Key, typename _Value, typename _Alloc,
1786  typename _ExtractKey, typename _Equal,
1787  typename _Hash, typename _RangeHash, typename _Unused,
1788  typename _RehashPolicy, typename _Traits>
1789  auto
1790  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1791  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1792  equal_range(const key_type& __k)
1793  -> pair<iterator, iterator>
1794  {
1795  auto __ite = find(__k);
1796  if (!__ite._M_cur)
1797  return { __ite, __ite };
1798 
1799  auto __beg = __ite++;
1800  if (__unique_keys::value)
1801  return { __beg, __ite };
1802 
1803  // All equivalent values are next to each other, if we find a
1804  // non-equivalent value after an equivalent one it means that we won't
1805  // find any new equivalent value.
1806  while (__ite._M_cur && this->_M_node_equals(*__beg._M_cur, *__ite._M_cur))
1807  ++__ite;
1808 
1809  return { __beg, __ite };
1810  }
1811 
1812  template<typename _Key, typename _Value, typename _Alloc,
1813  typename _ExtractKey, typename _Equal,
1814  typename _Hash, typename _RangeHash, typename _Unused,
1815  typename _RehashPolicy, typename _Traits>
1816  auto
1817  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1818  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1819  equal_range(const key_type& __k) const
1820  -> pair<const_iterator, const_iterator>
1821  {
1822  auto __ite = find(__k);
1823  if (!__ite._M_cur)
1824  return { __ite, __ite };
1825 
1826  auto __beg = __ite++;
1827  if (__unique_keys::value)
1828  return { __beg, __ite };
1829 
1830  // All equivalent values are next to each other, if we find a
1831  // non-equivalent value after an equivalent one it means that we won't
1832  // find any new equivalent value.
1833  while (__ite._M_cur && this->_M_node_equals(*__beg._M_cur, *__ite._M_cur))
1834  ++__ite;
1835 
1836  return { __beg, __ite };
1837  }
1838 
1839 #if __cplusplus > 201703L
1840  template<typename _Key, typename _Value, typename _Alloc,
1841  typename _ExtractKey, typename _Equal,
1842  typename _Hash, typename _RangeHash, typename _Unused,
1843  typename _RehashPolicy, typename _Traits>
1844  template<typename _Kt, typename, typename>
1845  auto
1846  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1847  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1848  _M_equal_range_tr(const _Kt& __k)
1849  -> pair<iterator, iterator>
1850  {
1851  __hash_code __code = this->_M_hash_code_tr(__k);
1852  std::size_t __bkt = _M_bucket_index(__code);
1853  auto __n = _M_find_node_tr(__bkt, __k, __code);
1854  iterator __ite(__n);
1855  if (!__n)
1856  return { __ite, __ite };
1857 
1858  // All equivalent values are next to each other, if we find a
1859  // non-equivalent value after an equivalent one it means that we won't
1860  // find any new equivalent value.
1861  auto __beg = __ite++;
1862  while (__ite._M_cur && this->_M_equals_tr(__k, __code, *__ite._M_cur))
1863  ++__ite;
1864 
1865  return { __beg, __ite };
1866  }
1867 
1868  template<typename _Key, typename _Value, typename _Alloc,
1869  typename _ExtractKey, typename _Equal,
1870  typename _Hash, typename _RangeHash, typename _Unused,
1871  typename _RehashPolicy, typename _Traits>
1872  template<typename _Kt, typename, typename>
1873  auto
1874  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1875  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1876  _M_equal_range_tr(const _Kt& __k) const
1877  -> pair<const_iterator, const_iterator>
1878  {
1879  __hash_code __code = this->_M_hash_code_tr(__k);
1880  std::size_t __bkt = _M_bucket_index(__code);
1881  auto __n = _M_find_node_tr(__bkt, __k, __code);
1882  const_iterator __ite(__n);
1883  if (!__n)
1884  return { __ite, __ite };
1885 
1886  // All equivalent values are next to each other, if we find a
1887  // non-equivalent value after an equivalent one it means that we won't
1888  // find any new equivalent value.
1889  auto __beg = __ite++;
1890  while (__ite._M_cur && this->_M_equals_tr(__k, __code, *__ite._M_cur))
1891  ++__ite;
1892 
1893  return { __beg, __ite };
1894  }
1895 #endif
1896 
1897  // Find the node before the one whose key compares equal to k.
1898  // Return nullptr if no node is found.
1899  template<typename _Key, typename _Value, typename _Alloc,
1900  typename _ExtractKey, typename _Equal,
1901  typename _Hash, typename _RangeHash, typename _Unused,
1902  typename _RehashPolicy, typename _Traits>
1903  auto
1904  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1905  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1906  _M_find_before_node(const key_type& __k)
1907  -> __node_base_ptr
1908  {
1909  __node_base_ptr __prev_p = &_M_before_begin;
1910  if (!__prev_p->_M_nxt)
1911  return nullptr;
1912 
1913  for (__node_ptr __p = static_cast<__node_ptr>(__prev_p->_M_nxt);
1914  __p != nullptr;
1915  __p = __p->_M_next())
1916  {
1917  if (this->_M_key_equals(__k, *__p))
1918  return __prev_p;
1919 
1920  __prev_p = __p;
1921  }
1922 
1923  return nullptr;
1924  }
1925 
1926  // Find the node before the one whose key compares equal to k in the bucket
1927  // bkt. Return nullptr if no node is found.
1928  template<typename _Key, typename _Value, typename _Alloc,
1929  typename _ExtractKey, typename _Equal,
1930  typename _Hash, typename _RangeHash, typename _Unused,
1931  typename _RehashPolicy, typename _Traits>
1932  auto
1933  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1934  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1935  _M_find_before_node(size_type __bkt, const key_type& __k,
1936  __hash_code __code) const
1937  -> __node_base_ptr
1938  {
1939  __node_base_ptr __prev_p = _M_buckets[__bkt];
1940  if (!__prev_p)
1941  return nullptr;
1942 
1943  for (__node_ptr __p = static_cast<__node_ptr>(__prev_p->_M_nxt);;
1944  __p = __p->_M_next())
1945  {
1946  if (this->_M_equals(__k, __code, *__p))
1947  return __prev_p;
1948 
1949  if (!__p->_M_nxt || _M_bucket_index(*__p->_M_next()) != __bkt)
1950  break;
1951  __prev_p = __p;
1952  }
1953 
1954  return nullptr;
1955  }
1956 
1957  template<typename _Key, typename _Value, typename _Alloc,
1958  typename _ExtractKey, typename _Equal,
1959  typename _Hash, typename _RangeHash, typename _Unused,
1960  typename _RehashPolicy, typename _Traits>
1961  template<typename _Kt>
1962  auto
1963  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1964  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1965  _M_find_before_node_tr(size_type __bkt, const _Kt& __k,
1966  __hash_code __code) const
1967  -> __node_base_ptr
1968  {
1969  __node_base_ptr __prev_p = _M_buckets[__bkt];
1970  if (!__prev_p)
1971  return nullptr;
1972 
1973  for (__node_ptr __p = static_cast<__node_ptr>(__prev_p->_M_nxt);;
1974  __p = __p->_M_next())
1975  {
1976  if (this->_M_equals_tr(__k, __code, *__p))
1977  return __prev_p;
1978 
1979  if (!__p->_M_nxt || _M_bucket_index(*__p->_M_next()) != __bkt)
1980  break;
1981  __prev_p = __p;
1982  }
1983 
1984  return nullptr;
1985  }
1986 
1987  template<typename _Key, typename _Value, typename _Alloc,
1988  typename _ExtractKey, typename _Equal,
1989  typename _Hash, typename _RangeHash, typename _Unused,
1990  typename _RehashPolicy, typename _Traits>
1991  void
1992  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1993  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
1994  _M_insert_bucket_begin(size_type __bkt, __node_ptr __node)
1995  {
1996  if (_M_buckets[__bkt])
1997  {
1998  // Bucket is not empty, we just need to insert the new node
1999  // after the bucket before begin.
2000  __node->_M_nxt = _M_buckets[__bkt]->_M_nxt;
2001  _M_buckets[__bkt]->_M_nxt = __node;
2002  }
2003  else
2004  {
2005  // The bucket is empty, the new node is inserted at the
2006  // beginning of the singly-linked list and the bucket will
2007  // contain _M_before_begin pointer.
2008  __node->_M_nxt = _M_before_begin._M_nxt;
2009  _M_before_begin._M_nxt = __node;
2010 
2011  if (__node->_M_nxt)
2012  // We must update former begin bucket that is pointing to
2013  // _M_before_begin.
2014  _M_buckets[_M_bucket_index(*__node->_M_next())] = __node;
2015 
2016  _M_buckets[__bkt] = &_M_before_begin;
2017  }
2018  }
2019 
2020  template<typename _Key, typename _Value, typename _Alloc,
2021  typename _ExtractKey, typename _Equal,
2022  typename _Hash, typename _RangeHash, typename _Unused,
2023  typename _RehashPolicy, typename _Traits>
2024  void
2025  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2026  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2027  _M_remove_bucket_begin(size_type __bkt, __node_ptr __next,
2028  size_type __next_bkt)
2029  {
2030  if (!__next || __next_bkt != __bkt)
2031  {
2032  // Bucket is now empty
2033  // First update next bucket if any
2034  if (__next)
2035  _M_buckets[__next_bkt] = _M_buckets[__bkt];
2036 
2037  // Second update before begin node if necessary
2038  if (&_M_before_begin == _M_buckets[__bkt])
2039  _M_before_begin._M_nxt = __next;
2040  _M_buckets[__bkt] = nullptr;
2041  }
2042  }
2043 
2044  template<typename _Key, typename _Value, typename _Alloc,
2045  typename _ExtractKey, typename _Equal,
2046  typename _Hash, typename _RangeHash, typename _Unused,
2047  typename _RehashPolicy, typename _Traits>
2048  auto
2049  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2050  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2051  _M_get_previous_node(size_type __bkt, __node_ptr __n)
2052  -> __node_base_ptr
2053  {
2054  __node_base_ptr __prev_n = _M_buckets[__bkt];
2055  while (__prev_n->_M_nxt != __n)
2056  __prev_n = __prev_n->_M_nxt;
2057  return __prev_n;
2058  }
2059 
2060  template<typename _Key, typename _Value, typename _Alloc,
2061  typename _ExtractKey, typename _Equal,
2062  typename _Hash, typename _RangeHash, typename _Unused,
2063  typename _RehashPolicy, typename _Traits>
2064  template<typename... _Args>
2065  auto
2066  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2067  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2068  _M_emplace(true_type /* __uks */, _Args&&... __args)
2069  -> pair<iterator, bool>
2070  {
2071  // First build the node to get access to the hash code
2072  _Scoped_node __node { this, std::forward<_Args>(__args)... };
2073  const key_type& __k = _ExtractKey{}(__node._M_node->_M_v());
2074  if (size() <= __small_size_threshold())
2075  {
2076  for (auto __it = begin(); __it != end(); ++__it)
2077  if (this->_M_key_equals(__k, *__it._M_cur))
2078  // There is already an equivalent node, no insertion
2079  return { __it, false };
2080  }
2081 
2082  __hash_code __code = this->_M_hash_code(__k);
2083  size_type __bkt = _M_bucket_index(__code);
2084  if (size() > __small_size_threshold())
2085  if (__node_ptr __p = _M_find_node(__bkt, __k, __code))
2086  // There is already an equivalent node, no insertion
2087  return { iterator(__p), false };
2088 
2089  // Insert the node
2090  auto __pos = _M_insert_unique_node(__bkt, __code, __node._M_node);
2091  __node._M_node = nullptr;
2092  return { __pos, true };
2093  }
2094 
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... _Args>
2100  auto
2101  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2102  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2103  _M_emplace(const_iterator __hint, false_type /* __uks */,
2104  _Args&&... __args)
2105  -> iterator
2106  {
2107  // First build the node to get its hash code.
2108  _Scoped_node __node { this, std::forward<_Args>(__args)... };
2109  const key_type& __k = _ExtractKey{}(__node._M_node->_M_v());
2110 
2111  auto __res = this->_M_compute_hash_code(__hint, __k);
2112  auto __pos
2113  = _M_insert_multi_node(__res.first._M_cur, __res.second,
2114  __node._M_node);
2115  __node._M_node = nullptr;
2116  return __pos;
2117  }
2118 
2119  template<typename _Key, typename _Value, typename _Alloc,
2120  typename _ExtractKey, typename _Equal,
2121  typename _Hash, typename _RangeHash, typename _Unused,
2122  typename _RehashPolicy, typename _Traits>
2123  auto
2124  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2125  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2126  _M_compute_hash_code(const_iterator __hint, const key_type& __k) const
2127  -> pair<const_iterator, __hash_code>
2128  {
2129  if (size() <= __small_size_threshold())
2130  {
2131  if (__hint != cend())
2132  {
2133  for (auto __it = __hint; __it != cend(); ++__it)
2134  if (this->_M_key_equals(__k, *__it._M_cur))
2135  return { __it, this->_M_hash_code(*__it._M_cur) };
2136  }
2137 
2138  for (auto __it = cbegin(); __it != __hint; ++__it)
2139  if (this->_M_key_equals(__k, *__it._M_cur))
2140  return { __it, this->_M_hash_code(*__it._M_cur) };
2141  }
2142 
2143  return { __hint, this->_M_hash_code(__k) };
2144  }
2145 
2146  template<typename _Key, typename _Value, typename _Alloc,
2147  typename _ExtractKey, typename _Equal,
2148  typename _Hash, typename _RangeHash, typename _Unused,
2149  typename _RehashPolicy, typename _Traits>
2150  auto
2151  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2152  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2153  _M_insert_unique_node(size_type __bkt, __hash_code __code,
2154  __node_ptr __node, size_type __n_elt)
2155  -> iterator
2156  {
2157  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
2158  std::pair<bool, std::size_t> __do_rehash
2159  = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count,
2160  __n_elt);
2161 
2162  if (__do_rehash.first)
2163  {
2164  _M_rehash(__do_rehash.second, __saved_state);
2165  __bkt = _M_bucket_index(__code);
2166  }
2167 
2168  this->_M_store_code(*__node, __code);
2169 
2170  // Always insert at the beginning of the bucket.
2171  _M_insert_bucket_begin(__bkt, __node);
2172  ++_M_element_count;
2173  return iterator(__node);
2174  }
2175 
2176  template<typename _Key, typename _Value, typename _Alloc,
2177  typename _ExtractKey, typename _Equal,
2178  typename _Hash, typename _RangeHash, typename _Unused,
2179  typename _RehashPolicy, typename _Traits>
2180  auto
2181  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2182  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2183  _M_insert_multi_node(__node_ptr __hint,
2184  __hash_code __code, __node_ptr __node)
2185  -> iterator
2186  {
2187  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
2188  std::pair<bool, std::size_t> __do_rehash
2189  = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count, 1);
2190 
2191  if (__do_rehash.first)
2192  _M_rehash(__do_rehash.second, __saved_state);
2193 
2194  this->_M_store_code(*__node, __code);
2195  const key_type& __k = _ExtractKey{}(__node->_M_v());
2196  size_type __bkt = _M_bucket_index(__code);
2197 
2198  // Find the node before an equivalent one or use hint if it exists and
2199  // if it is equivalent.
2200  __node_base_ptr __prev
2201  = __builtin_expect(__hint != nullptr, false)
2202  && this->_M_equals(__k, __code, *__hint)
2203  ? __hint
2204  : _M_find_before_node(__bkt, __k, __code);
2205 
2206  if (__prev)
2207  {
2208  // Insert after the node before the equivalent one.
2209  __node->_M_nxt = __prev->_M_nxt;
2210  __prev->_M_nxt = __node;
2211  if (__builtin_expect(__prev == __hint, false))
2212  // hint might be the last bucket node, in this case we need to
2213  // update next bucket.
2214  if (__node->_M_nxt
2215  && !this->_M_equals(__k, __code, *__node->_M_next()))
2216  {
2217  size_type __next_bkt = _M_bucket_index(*__node->_M_next());
2218  if (__next_bkt != __bkt)
2219  _M_buckets[__next_bkt] = __node;
2220  }
2221  }
2222  else
2223  // The inserted node has no equivalent in the hashtable. We must
2224  // insert the new node at the beginning of the bucket to preserve
2225  // equivalent elements' relative positions.
2226  _M_insert_bucket_begin(__bkt, __node);
2227  ++_M_element_count;
2228  return iterator(__node);
2229  }
2230 
2231  // Insert v if no element with its key is already present.
2232  template<typename _Key, typename _Value, typename _Alloc,
2233  typename _ExtractKey, typename _Equal,
2234  typename _Hash, typename _RangeHash, typename _Unused,
2235  typename _RehashPolicy, typename _Traits>
2236  template<typename _Kt, typename _Arg, typename _NodeGenerator>
2237  auto
2238  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2239  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2240  _M_insert_unique(_Kt&& __k, _Arg&& __v,
2241  const _NodeGenerator& __node_gen)
2242  -> pair<iterator, bool>
2243  {
2244  if (size() <= __small_size_threshold())
2245  for (auto __it = begin(); __it != end(); ++__it)
2246  if (this->_M_key_equals_tr(__k, *__it._M_cur))
2247  return { __it, false };
2248 
2249  __hash_code __code = this->_M_hash_code_tr(__k);
2250  size_type __bkt = _M_bucket_index(__code);
2251 
2252  if (size() > __small_size_threshold())
2253  if (__node_ptr __node = _M_find_node_tr(__bkt, __k, __code))
2254  return { iterator(__node), false };
2255 
2256  _Scoped_node __node {
2257  __node_builder_t::_S_build(std::forward<_Kt>(__k),
2258  std::forward<_Arg>(__v),
2259  __node_gen),
2260  this
2261  };
2262  auto __pos
2263  = _M_insert_unique_node(__bkt, __code, __node._M_node);
2264  __node._M_node = nullptr;
2265  return { __pos, true };
2266  }
2267 
2268  // Insert v unconditionally.
2269  template<typename _Key, typename _Value, typename _Alloc,
2270  typename _ExtractKey, typename _Equal,
2271  typename _Hash, typename _RangeHash, typename _Unused,
2272  typename _RehashPolicy, typename _Traits>
2273  template<typename _Arg, typename _NodeGenerator>
2274  auto
2275  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2276  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2277  _M_insert(const_iterator __hint, _Arg&& __v,
2278  const _NodeGenerator& __node_gen,
2279  false_type /* __uks */)
2280  -> iterator
2281  {
2282  // First allocate new node so that we don't do anything if it throws.
2283  _Scoped_node __node{ __node_gen(std::forward<_Arg>(__v)), this };
2284 
2285  // Second compute the hash code so that we don't rehash if it throws.
2286  auto __res = this->_M_compute_hash_code(
2287  __hint, _ExtractKey{}(__node._M_node->_M_v()));
2288 
2289  auto __pos
2290  = _M_insert_multi_node(__res.first._M_cur, __res.second,
2291  __node._M_node);
2292  __node._M_node = nullptr;
2293  return __pos;
2294  }
2295 
2296  template<typename _Key, typename _Value, typename _Alloc,
2297  typename _ExtractKey, typename _Equal,
2298  typename _Hash, typename _RangeHash, typename _Unused,
2299  typename _RehashPolicy, typename _Traits>
2300  auto
2301  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2302  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2303  erase(const_iterator __it)
2304  -> iterator
2305  {
2306  __node_ptr __n = __it._M_cur;
2307  std::size_t __bkt = _M_bucket_index(*__n);
2308 
2309  // Look for previous node to unlink it from the erased one, this
2310  // is why we need buckets to contain the before begin to make
2311  // this search fast.
2312  __node_base_ptr __prev_n = _M_get_previous_node(__bkt, __n);
2313  return _M_erase(__bkt, __prev_n, __n);
2314  }
2315 
2316  template<typename _Key, typename _Value, typename _Alloc,
2317  typename _ExtractKey, typename _Equal,
2318  typename _Hash, typename _RangeHash, typename _Unused,
2319  typename _RehashPolicy, typename _Traits>
2320  auto
2321  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2322  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2323  _M_erase(size_type __bkt, __node_base_ptr __prev_n, __node_ptr __n)
2324  -> iterator
2325  {
2326  if (__prev_n == _M_buckets[__bkt])
2327  _M_remove_bucket_begin(__bkt, __n->_M_next(),
2328  __n->_M_nxt ? _M_bucket_index(*__n->_M_next()) : 0);
2329  else if (__n->_M_nxt)
2330  {
2331  size_type __next_bkt = _M_bucket_index(*__n->_M_next());
2332  if (__next_bkt != __bkt)
2333  _M_buckets[__next_bkt] = __prev_n;
2334  }
2335 
2336  __prev_n->_M_nxt = __n->_M_nxt;
2337  iterator __result(__n->_M_next());
2338  this->_M_deallocate_node(__n);
2339  --_M_element_count;
2340 
2341  return __result;
2342  }
2343 
2344  template<typename _Key, typename _Value, typename _Alloc,
2345  typename _ExtractKey, typename _Equal,
2346  typename _Hash, typename _RangeHash, typename _Unused,
2347  typename _RehashPolicy, typename _Traits>
2348  auto
2349  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2350  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2351  _M_erase(true_type /* __uks */, const key_type& __k)
2352  -> size_type
2353  {
2354  __node_base_ptr __prev_n;
2355  __node_ptr __n;
2356  std::size_t __bkt;
2357  if (size() <= __small_size_threshold())
2358  {
2359  __prev_n = _M_find_before_node(__k);
2360  if (!__prev_n)
2361  return 0;
2362 
2363  // We found a matching node, erase it.
2364  __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
2365  __bkt = _M_bucket_index(*__n);
2366  }
2367  else
2368  {
2369  __hash_code __code = this->_M_hash_code(__k);
2370  __bkt = _M_bucket_index(__code);
2371 
2372  // Look for the node before the first matching node.
2373  __prev_n = _M_find_before_node(__bkt, __k, __code);
2374  if (!__prev_n)
2375  return 0;
2376 
2377  // We found a matching node, erase it.
2378  __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
2379  }
2380 
2381  _M_erase(__bkt, __prev_n, __n);
2382  return 1;
2383  }
2384 
2385  template<typename _Key, typename _Value, typename _Alloc,
2386  typename _ExtractKey, typename _Equal,
2387  typename _Hash, typename _RangeHash, typename _Unused,
2388  typename _RehashPolicy, typename _Traits>
2389  auto
2390  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2391  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2392  _M_erase(false_type /* __uks */, const key_type& __k)
2393  -> size_type
2394  {
2395  std::size_t __bkt;
2396  __node_base_ptr __prev_n;
2397  __node_ptr __n;
2398  if (size() <= __small_size_threshold())
2399  {
2400  __prev_n = _M_find_before_node(__k);
2401  if (!__prev_n)
2402  return 0;
2403 
2404  // We found a matching node, erase it.
2405  __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
2406  __bkt = _M_bucket_index(*__n);
2407  }
2408  else
2409  {
2410  __hash_code __code = this->_M_hash_code(__k);
2411  __bkt = _M_bucket_index(__code);
2412 
2413  // Look for the node before the first matching node.
2414  __prev_n = _M_find_before_node(__bkt, __k, __code);
2415  if (!__prev_n)
2416  return 0;
2417 
2418  __n = static_cast<__node_ptr>(__prev_n->_M_nxt);
2419  }
2420 
2421  // _GLIBCXX_RESOLVE_LIB_DEFECTS
2422  // 526. Is it undefined if a function in the standard changes
2423  // in parameters?
2424  // We use one loop to find all matching nodes and another to deallocate
2425  // them so that the key stays valid during the first loop. It might be
2426  // invalidated indirectly when destroying nodes.
2427  __node_ptr __n_last = __n->_M_next();
2428  while (__n_last && this->_M_node_equals(*__n, *__n_last))
2429  __n_last = __n_last->_M_next();
2430 
2431  std::size_t __n_last_bkt = __n_last ? _M_bucket_index(*__n_last) : __bkt;
2432 
2433  // Deallocate nodes.
2434  size_type __result = 0;
2435  do
2436  {
2437  __node_ptr __p = __n->_M_next();
2438  this->_M_deallocate_node(__n);
2439  __n = __p;
2440  ++__result;
2441  }
2442  while (__n != __n_last);
2443 
2444  _M_element_count -= __result;
2445  if (__prev_n == _M_buckets[__bkt])
2446  _M_remove_bucket_begin(__bkt, __n_last, __n_last_bkt);
2447  else if (__n_last_bkt != __bkt)
2448  _M_buckets[__n_last_bkt] = __prev_n;
2449  __prev_n->_M_nxt = __n_last;
2450  return __result;
2451  }
2452 
2453  template<typename _Key, typename _Value, typename _Alloc,
2454  typename _ExtractKey, typename _Equal,
2455  typename _Hash, typename _RangeHash, typename _Unused,
2456  typename _RehashPolicy, typename _Traits>
2457  auto
2458  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2459  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2460  erase(const_iterator __first, const_iterator __last)
2461  -> iterator
2462  {
2463  __node_ptr __n = __first._M_cur;
2464  __node_ptr __last_n = __last._M_cur;
2465  if (__n == __last_n)
2466  return iterator(__n);
2467 
2468  std::size_t __bkt = _M_bucket_index(*__n);
2469 
2470  __node_base_ptr __prev_n = _M_get_previous_node(__bkt, __n);
2471  bool __is_bucket_begin = __n == _M_bucket_begin(__bkt);
2472  std::size_t __n_bkt = __bkt;
2473  for (;;)
2474  {
2475  do
2476  {
2477  __node_ptr __tmp = __n;
2478  __n = __n->_M_next();
2479  this->_M_deallocate_node(__tmp);
2480  --_M_element_count;
2481  if (!__n)
2482  break;
2483  __n_bkt = _M_bucket_index(*__n);
2484  }
2485  while (__n != __last_n && __n_bkt == __bkt);
2486  if (__is_bucket_begin)
2487  _M_remove_bucket_begin(__bkt, __n, __n_bkt);
2488  if (__n == __last_n)
2489  break;
2490  __is_bucket_begin = true;
2491  __bkt = __n_bkt;
2492  }
2493 
2494  if (__n && (__n_bkt != __bkt || __is_bucket_begin))
2495  _M_buckets[__n_bkt] = __prev_n;
2496  __prev_n->_M_nxt = __n;
2497  return iterator(__n);
2498  }
2499 
2500  template<typename _Key, typename _Value, typename _Alloc,
2501  typename _ExtractKey, typename _Equal,
2502  typename _Hash, typename _RangeHash, typename _Unused,
2503  typename _RehashPolicy, typename _Traits>
2504  void
2505  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2506  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2507  clear() noexcept
2508  {
2509  this->_M_deallocate_nodes(_M_begin());
2510  __builtin_memset(_M_buckets, 0,
2511  _M_bucket_count * sizeof(__node_base_ptr));
2512  _M_element_count = 0;
2513  _M_before_begin._M_nxt = nullptr;
2514  }
2515 
2516  template<typename _Key, typename _Value, typename _Alloc,
2517  typename _ExtractKey, typename _Equal,
2518  typename _Hash, typename _RangeHash, typename _Unused,
2519  typename _RehashPolicy, typename _Traits>
2520  void
2521  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2522  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2523  rehash(size_type __bkt_count)
2524  {
2525  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
2526  __bkt_count
2527  = std::max(_M_rehash_policy._M_bkt_for_elements(_M_element_count + 1),
2528  __bkt_count);
2529  __bkt_count = _M_rehash_policy._M_next_bkt(__bkt_count);
2530 
2531  if (__bkt_count != _M_bucket_count)
2532  _M_rehash(__bkt_count, __saved_state);
2533  else
2534  // No rehash, restore previous state to keep it consistent with
2535  // container state.
2536  _M_rehash_policy._M_reset(__saved_state);
2537  }
2538 
2539  template<typename _Key, typename _Value, typename _Alloc,
2540  typename _ExtractKey, typename _Equal,
2541  typename _Hash, typename _RangeHash, typename _Unused,
2542  typename _RehashPolicy, typename _Traits>
2543  void
2544  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2545  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2546  _M_rehash(size_type __bkt_count, const __rehash_state& __state)
2547  {
2548  __try
2549  {
2550  _M_rehash_aux(__bkt_count, __unique_keys{});
2551  }
2552  __catch(...)
2553  {
2554  // A failure here means that buckets allocation failed. We only
2555  // have to restore hash policy previous state.
2556  _M_rehash_policy._M_reset(__state);
2557  __throw_exception_again;
2558  }
2559  }
2560 
2561  // Rehash when there is no equivalent elements.
2562  template<typename _Key, typename _Value, typename _Alloc,
2563  typename _ExtractKey, typename _Equal,
2564  typename _Hash, typename _RangeHash, typename _Unused,
2565  typename _RehashPolicy, typename _Traits>
2566  void
2567  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2568  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2569  _M_rehash_aux(size_type __bkt_count, true_type /* __uks */)
2570  {
2571  __buckets_ptr __new_buckets = _M_allocate_buckets(__bkt_count);
2572  __node_ptr __p = _M_begin();
2573  _M_before_begin._M_nxt = nullptr;
2574  std::size_t __bbegin_bkt = 0;
2575  while (__p)
2576  {
2577  __node_ptr __next = __p->_M_next();
2578  std::size_t __bkt
2579  = __hash_code_base::_M_bucket_index(*__p, __bkt_count);
2580  if (!__new_buckets[__bkt])
2581  {
2582  __p->_M_nxt = _M_before_begin._M_nxt;
2583  _M_before_begin._M_nxt = __p;
2584  __new_buckets[__bkt] = &_M_before_begin;
2585  if (__p->_M_nxt)
2586  __new_buckets[__bbegin_bkt] = __p;
2587  __bbegin_bkt = __bkt;
2588  }
2589  else
2590  {
2591  __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
2592  __new_buckets[__bkt]->_M_nxt = __p;
2593  }
2594 
2595  __p = __next;
2596  }
2597 
2598  _M_deallocate_buckets();
2599  _M_bucket_count = __bkt_count;
2600  _M_buckets = __new_buckets;
2601  }
2602 
2603  // Rehash when there can be equivalent elements, preserve their relative
2604  // order.
2605  template<typename _Key, typename _Value, typename _Alloc,
2606  typename _ExtractKey, typename _Equal,
2607  typename _Hash, typename _RangeHash, typename _Unused,
2608  typename _RehashPolicy, typename _Traits>
2609  void
2610  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2611  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
2612  _M_rehash_aux(size_type __bkt_count, false_type /* __uks */)
2613  {
2614  __buckets_ptr __new_buckets = _M_allocate_buckets(__bkt_count);
2615  __node_ptr __p = _M_begin();
2616  _M_before_begin._M_nxt = nullptr;
2617  std::size_t __bbegin_bkt = 0;
2618  std::size_t __prev_bkt = 0;
2619  __node_ptr __prev_p = nullptr;
2620  bool __check_bucket = false;
2621 
2622  while (__p)
2623  {
2624  __node_ptr __next = __p->_M_next();
2625  std::size_t __bkt
2626  = __hash_code_base::_M_bucket_index(*__p, __bkt_count);
2627 
2628  if (__prev_p && __prev_bkt == __bkt)
2629  {
2630  // Previous insert was already in this bucket, we insert after
2631  // the previously inserted one to preserve equivalent elements
2632  // relative order.
2633  __p->_M_nxt = __prev_p->_M_nxt;
2634  __prev_p->_M_nxt = __p;
2635 
2636  // Inserting after a node in a bucket require to check that we
2637  // haven't change the bucket last node, in this case next
2638  // bucket containing its before begin node must be updated. We
2639  // schedule a check as soon as we move out of the sequence of
2640  // equivalent nodes to limit the number of checks.
2641  __check_bucket = true;
2642  }
2643  else
2644  {
2645  if (__check_bucket)
2646  {
2647  // Check if we shall update the next bucket because of
2648  // insertions into __prev_bkt bucket.
2649  if (__prev_p->_M_nxt)
2650  {
2651  std::size_t __next_bkt
2652  = __hash_code_base::_M_bucket_index(
2653  *__prev_p->_M_next(), __bkt_count);
2654  if (__next_bkt != __prev_bkt)
2655  __new_buckets[__next_bkt] = __prev_p;
2656  }
2657  __check_bucket = false;
2658  }
2659 
2660  if (!__new_buckets[__bkt])
2661  {
2662  __p->_M_nxt = _M_before_begin._M_nxt;
2663  _M_before_begin._M_nxt = __p;
2664  __new_buckets[__bkt] = &_M_before_begin;
2665  if (__p->_M_nxt)
2666  __new_buckets[__bbegin_bkt] = __p;
2667  __bbegin_bkt = __bkt;
2668  }
2669  else
2670  {
2671  __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
2672  __new_buckets[__bkt]->_M_nxt = __p;
2673  }
2674  }
2675  __prev_p = __p;
2676  __prev_bkt = __bkt;
2677  __p = __next;
2678  }
2679 
2680  if (__check_bucket && __prev_p->_M_nxt)
2681  {
2682  std::size_t __next_bkt
2683  = __hash_code_base::_M_bucket_index(*__prev_p->_M_next(),
2684  __bkt_count);
2685  if (__next_bkt != __prev_bkt)
2686  __new_buckets[__next_bkt] = __prev_p;
2687  }
2688 
2689  _M_deallocate_buckets();
2690  _M_bucket_count = __bkt_count;
2691  _M_buckets = __new_buckets;
2692  }
2693 
2694 #if __cplusplus > 201402L
2695  template<typename, typename, typename> class _Hash_merge_helper { };
2696 #endif // C++17
2697 
2698 #if __cpp_deduction_guides >= 201606
2699  // Used to constrain deduction guides
2700  template<typename _Hash>
2701  using _RequireNotAllocatorOrIntegral
2702  = __enable_if_t<!__or_<is_integral<_Hash>, __is_allocator<_Hash>>::value>;
2703 #endif
2704 
2705 /// @endcond
2706 _GLIBCXX_END_NAMESPACE_VERSION
2707 } // namespace std
2708 
2709 #endif // _HASHTABLE_H
hashtable_policy.h
std::size
constexpr auto size(const _Container &__cont) noexcept(noexcept(__cont.size())) -> decltype(__cont.size())
Return the size of a container.
Definition: range_access.h:264
node_handle.h
std::pair::second
_T2 second
The second member.
Definition: stl_pair.h:194
std::cbegin
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:126
std::__addressof
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
Definition: move.h:51
std::end
_Tp * end(valarray< _Tp > &__va) noexcept
Return an iterator pointing to one past the last element of the valarray.
Definition: valarray:1243
enable_special_members.h
std::true_type
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:82
std::empty
constexpr auto empty(const _Container &__cont) noexcept(noexcept(__cont.empty())) -> decltype(__cont.empty())
Return whether a container is empty.
Definition: range_access.h:284
std::cend
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:138
std::pair::first
_T1 first
The first member.
Definition: stl_pair.h:193
std::false_type
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:85
std::distance
constexpr iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
Definition: stl_iterator_base_funcs.h:148
std::begin
_Tp * begin(valarray< _Tp > &__va) noexcept
Return an iterator pointing to the first element of the valarray.
Definition: valarray:1221
std
ISO C++ entities toplevel namespace is std.
stl_function.h
std::forward
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
Definition: move.h:70
std::move
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:97
std::pair
Struct holding two objects of arbitrary type.
Definition: bits/stl_iterator.h:2993
std::max
constexpr const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:257