libstdc++
bits/hashtable.h
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1 // hashtable.h header -*- C++ -*-
2 
3 // Copyright (C) 2007-2014 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
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22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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24 
25 /** @file bits/hashtable.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{unordered_map, unordered_set}
28  */
29 
30 #ifndef _HASHTABLE_H
31 #define _HASHTABLE_H 1
32 
33 #pragma GCC system_header
34 
35 #include <bits/hashtable_policy.h>
36 
37 namespace std _GLIBCXX_VISIBILITY(default)
38 {
39 _GLIBCXX_BEGIN_NAMESPACE_VERSION
40 
41  template<typename _Tp, typename _Hash>
42  using __cache_default
43  = __not_<__and_<// Do not cache for fast hasher.
44  __is_fast_hash<_Hash>,
45  // Mandatory to have erase not throwing.
46  __detail::__is_noexcept_hash<_Tp, _Hash>>>;
47 
48  /**
49  * Primary class template _Hashtable.
50  *
51  * @ingroup hashtable-detail
52  *
53  * @tparam _Value CopyConstructible type.
54  *
55  * @tparam _Key CopyConstructible type.
56  *
57  * @tparam _Alloc An allocator type
58  * ([lib.allocator.requirements]) whose _Alloc::value_type is
59  * _Value. As a conforming extension, we allow for
60  * _Alloc::value_type != _Value.
61  *
62  * @tparam _ExtractKey Function object that takes an object of type
63  * _Value and returns a value of type _Key.
64  *
65  * @tparam _Equal Function object that takes two objects of type k
66  * and returns a bool-like value that is true if the two objects
67  * are considered equal.
68  *
69  * @tparam _H1 The hash function. A unary function object with
70  * argument type _Key and result type size_t. Return values should
71  * be distributed over the entire range [0, numeric_limits<size_t>:::max()].
72  *
73  * @tparam _H2 The range-hashing function (in the terminology of
74  * Tavori and Dreizin). A binary function object whose argument
75  * types and result type are all size_t. Given arguments r and N,
76  * the return value is in the range [0, N).
77  *
78  * @tparam _Hash The ranged hash function (Tavori and Dreizin). A
79  * binary function whose argument types are _Key and size_t and
80  * whose result type is size_t. Given arguments k and N, the
81  * return value is in the range [0, N). Default: hash(k, N) =
82  * h2(h1(k), N). If _Hash is anything other than the default, _H1
83  * and _H2 are ignored.
84  *
85  * @tparam _RehashPolicy Policy class with three members, all of
86  * which govern the bucket count. _M_next_bkt(n) returns a bucket
87  * count no smaller than n. _M_bkt_for_elements(n) returns a
88  * bucket count appropriate for an element count of n.
89  * _M_need_rehash(n_bkt, n_elt, n_ins) determines whether, if the
90  * current bucket count is n_bkt and the current element count is
91  * n_elt, we need to increase the bucket count. If so, returns
92  * make_pair(true, n), where n is the new bucket count. If not,
93  * returns make_pair(false, <anything>)
94  *
95  * @tparam _Traits Compile-time class with three boolean
96  * std::integral_constant members: __cache_hash_code, __constant_iterators,
97  * __unique_keys.
98  *
99  * Each _Hashtable data structure has:
100  *
101  * - _Bucket[] _M_buckets
102  * - _Hash_node_base _M_before_begin
103  * - size_type _M_bucket_count
104  * - size_type _M_element_count
105  *
106  * with _Bucket being _Hash_node* and _Hash_node containing:
107  *
108  * - _Hash_node* _M_next
109  * - Tp _M_value
110  * - size_t _M_hash_code if cache_hash_code is true
111  *
112  * In terms of Standard containers the hashtable is like the aggregation of:
113  *
114  * - std::forward_list<_Node> containing the elements
115  * - std::vector<std::forward_list<_Node>::iterator> representing the buckets
116  *
117  * The non-empty buckets contain the node before the first node in the
118  * bucket. This design makes it possible to implement something like a
119  * std::forward_list::insert_after on container insertion and
120  * std::forward_list::erase_after on container erase
121  * calls. _M_before_begin is equivalent to
122  * std::forward_list::before_begin. Empty buckets contain
123  * nullptr. Note that one of the non-empty buckets contains
124  * &_M_before_begin which is not a dereferenceable node so the
125  * node pointer in a bucket shall never be dereferenced, only its
126  * next node can be.
127  *
128  * Walking through a bucket's nodes requires a check on the hash code to
129  * see if each node is still in the bucket. Such a design assumes a
130  * quite efficient hash functor and is one of the reasons it is
131  * highly advisable to set __cache_hash_code to true.
132  *
133  * The container iterators are simply built from nodes. This way
134  * incrementing the iterator is perfectly efficient independent of
135  * how many empty buckets there are in the container.
136  *
137  * On insert we compute the element's hash code and use it to find the
138  * bucket index. If the element must be inserted in an empty bucket
139  * we add it at the beginning of the singly linked list and make the
140  * bucket point to _M_before_begin. The bucket that used to point to
141  * _M_before_begin, if any, is updated to point to its new before
142  * begin node.
143  *
144  * On erase, the simple iterator design requires using the hash
145  * functor to get the index of the bucket to update. For this
146  * reason, when __cache_hash_code is set to false the hash functor must
147  * not throw and this is enforced by a static assertion.
148  *
149  * Functionality is implemented by decomposition into base classes,
150  * where the derived _Hashtable class is used in _Map_base,
151  * _Insert, _Rehash_base, and _Equality base classes to access the
152  * "this" pointer. _Hashtable_base is used in the base classes as a
153  * non-recursive, fully-completed-type so that detailed nested type
154  * information, such as iterator type and node type, can be
155  * used. This is similar to the "Curiously Recurring Template
156  * Pattern" (CRTP) technique, but uses a reconstructed, not
157  * explicitly passed, template pattern.
158  *
159  * Base class templates are:
160  * - __detail::_Hashtable_base
161  * - __detail::_Map_base
162  * - __detail::_Insert
163  * - __detail::_Rehash_base
164  * - __detail::_Equality
165  */
166  template<typename _Key, typename _Value, typename _Alloc,
167  typename _ExtractKey, typename _Equal,
168  typename _H1, typename _H2, typename _Hash,
169  typename _RehashPolicy, typename _Traits>
171  : public __detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal,
172  _H1, _H2, _Hash, _Traits>,
173  public __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
174  _H1, _H2, _Hash, _RehashPolicy, _Traits>,
175  public __detail::_Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
176  _H1, _H2, _Hash, _RehashPolicy, _Traits>,
177  public __detail::_Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
178  _H1, _H2, _Hash, _RehashPolicy, _Traits>,
179  public __detail::_Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
180  _H1, _H2, _Hash, _RehashPolicy, _Traits>,
182  typename __alloctr_rebind<_Alloc,
183  __detail::_Hash_node<_Value,
184  _Traits::__hash_cached::value> >::__type>
185  {
186  using __traits_type = _Traits;
187  using __hash_cached = typename __traits_type::__hash_cached;
189  using __node_alloc_type =
190  typename __alloctr_rebind<_Alloc, __node_type>::__type;
191 
193 
194  using __value_alloc_traits =
196  using __node_alloc_traits =
198  using __node_base = typename __hashtable_alloc::__node_base;
199  using __bucket_type = typename __hashtable_alloc::__bucket_type;
200 
201  public:
202  typedef _Key key_type;
203  typedef _Value value_type;
204  typedef _Alloc allocator_type;
205  typedef _Equal key_equal;
206 
207  // mapped_type, if present, comes from _Map_base.
208  // hasher, if present, comes from _Hash_code_base/_Hashtable_base.
209  typedef typename __value_alloc_traits::pointer pointer;
210  typedef typename __value_alloc_traits::const_pointer const_pointer;
211  typedef value_type& reference;
212  typedef const value_type& const_reference;
213 
214  private:
215  using __rehash_type = _RehashPolicy;
216  using __rehash_state = typename __rehash_type::_State;
217 
218  using __constant_iterators = typename __traits_type::__constant_iterators;
219  using __unique_keys = typename __traits_type::__unique_keys;
220 
221  using __key_extract = typename std::conditional<
222  __constant_iterators::value,
223  __detail::_Identity,
224  __detail::_Select1st>::type;
225 
227  _Hashtable_base<_Key, _Value, _ExtractKey,
228  _Equal, _H1, _H2, _Hash, _Traits>;
229 
230  using __hash_code_base = typename __hashtable_base::__hash_code_base;
231  using __hash_code = typename __hashtable_base::__hash_code;
232  using __ireturn_type = typename __hashtable_base::__ireturn_type;
233 
234  using __map_base = __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey,
235  _Equal, _H1, _H2, _Hash,
236  _RehashPolicy, _Traits>;
237 
238  using __rehash_base = __detail::_Rehash_base<_Key, _Value, _Alloc,
239  _ExtractKey, _Equal,
240  _H1, _H2, _Hash,
241  _RehashPolicy, _Traits>;
242 
243  using __eq_base = __detail::_Equality<_Key, _Value, _Alloc, _ExtractKey,
244  _Equal, _H1, _H2, _Hash,
245  _RehashPolicy, _Traits>;
246 
247  using __reuse_or_alloc_node_type =
248  __detail::_ReuseOrAllocNode<__node_alloc_type>;
249 
250  // Metaprogramming for picking apart hash caching.
251  template<typename _Cond>
252  using __if_hash_cached = __or_<__not_<__hash_cached>, _Cond>;
253 
254  template<typename _Cond>
255  using __if_hash_not_cached = __or_<__hash_cached, _Cond>;
256 
257  // Compile-time diagnostics.
258 
259  // _Hash_code_base has everything protected, so use this derived type to
260  // access it.
261  struct __hash_code_base_access : __hash_code_base
262  { using __hash_code_base::_M_bucket_index; };
263 
264  // Getting a bucket index from a node shall not throw because it is used
265  // in methods (erase, swap...) that shall not throw.
266  static_assert(noexcept(declval<const __hash_code_base_access&>()
267  ._M_bucket_index((const __node_type*)nullptr,
268  (std::size_t)0)),
269  "Cache the hash code or qualify your functors involved"
270  " in hash code and bucket index computation with noexcept");
271 
272  // Following two static assertions are necessary to guarantee
273  // that local_iterator will be default constructible.
274 
275  // When hash codes are cached local iterator inherits from H2 functor
276  // which must then be default constructible.
277  static_assert(__if_hash_cached<is_default_constructible<_H2>>::value,
278  "Functor used to map hash code to bucket index"
279  " must be default constructible");
280 
281  template<typename _Keya, typename _Valuea, typename _Alloca,
282  typename _ExtractKeya, typename _Equala,
283  typename _H1a, typename _H2a, typename _Hasha,
284  typename _RehashPolicya, typename _Traitsa,
285  bool _Unique_keysa>
286  friend struct __detail::_Map_base;
287 
288  template<typename _Keya, typename _Valuea, typename _Alloca,
289  typename _ExtractKeya, typename _Equala,
290  typename _H1a, typename _H2a, typename _Hasha,
291  typename _RehashPolicya, typename _Traitsa>
292  friend struct __detail::_Insert_base;
293 
294  template<typename _Keya, typename _Valuea, typename _Alloca,
295  typename _ExtractKeya, typename _Equala,
296  typename _H1a, typename _H2a, typename _Hasha,
297  typename _RehashPolicya, typename _Traitsa,
298  bool _Constant_iteratorsa, bool _Unique_keysa>
299  friend struct __detail::_Insert;
300 
301  public:
302  using size_type = typename __hashtable_base::size_type;
303  using difference_type = typename __hashtable_base::difference_type;
304 
305  using iterator = typename __hashtable_base::iterator;
306  using const_iterator = typename __hashtable_base::const_iterator;
307 
308  using local_iterator = typename __hashtable_base::local_iterator;
309  using const_local_iterator = typename __hashtable_base::
311 
312  private:
313  __bucket_type* _M_buckets;
314  size_type _M_bucket_count;
315  __node_base _M_before_begin;
316  size_type _M_element_count;
317  _RehashPolicy _M_rehash_policy;
318 
320  _M_base_alloc() { return *this; }
321 
322  using __hashtable_alloc::_M_deallocate_buckets;
323 
324  void
325  _M_deallocate_buckets()
326  { this->_M_deallocate_buckets(_M_buckets, _M_bucket_count); }
327 
328  // Gets bucket begin, deals with the fact that non-empty buckets contain
329  // their before begin node.
330  __node_type*
331  _M_bucket_begin(size_type __bkt) const;
332 
333  __node_type*
334  _M_begin() const
335  { return static_cast<__node_type*>(_M_before_begin._M_nxt); }
336 
337  template<typename _NodeGenerator>
338  void
339  _M_assign(const _Hashtable&, const _NodeGenerator&);
340 
341  void
342  _M_move_assign(_Hashtable&&, std::true_type);
343 
344  void
345  _M_move_assign(_Hashtable&&, std::false_type);
346 
347  void
348  _M_reset() noexcept;
349 
350  public:
351  // Constructor, destructor, assignment, swap
352  _Hashtable(size_type __bucket_hint,
353  const _H1&, const _H2&, const _Hash&,
354  const _Equal&, const _ExtractKey&,
355  const allocator_type&);
356 
357  template<typename _InputIterator>
358  _Hashtable(_InputIterator __first, _InputIterator __last,
359  size_type __bucket_hint,
360  const _H1&, const _H2&, const _Hash&,
361  const _Equal&, const _ExtractKey&,
362  const allocator_type&);
363 
364  _Hashtable(const _Hashtable&);
365 
366  _Hashtable(_Hashtable&&) noexcept;
367 
368  _Hashtable(const _Hashtable&, const allocator_type&);
369 
370  _Hashtable(_Hashtable&&, const allocator_type&);
371 
372  // Use delegating constructors.
373  explicit
374  _Hashtable(const allocator_type& __a)
375  : _Hashtable(10, _H1(), _H2(), _Hash(), key_equal(),
376  __key_extract(), __a)
377  { }
378 
379  explicit
380  _Hashtable(size_type __n = 10,
381  const _H1& __hf = _H1(),
382  const key_equal& __eql = key_equal(),
383  const allocator_type& __a = allocator_type())
384  : _Hashtable(__n, __hf, _H2(), _Hash(), __eql,
385  __key_extract(), __a)
386  { }
387 
388  template<typename _InputIterator>
389  _Hashtable(_InputIterator __f, _InputIterator __l,
390  size_type __n = 0,
391  const _H1& __hf = _H1(),
392  const key_equal& __eql = key_equal(),
393  const allocator_type& __a = allocator_type())
394  : _Hashtable(__f, __l, __n, __hf, _H2(), _Hash(), __eql,
395  __key_extract(), __a)
396  { }
397 
399  size_type __n = 0,
400  const _H1& __hf = _H1(),
401  const key_equal& __eql = key_equal(),
402  const allocator_type& __a = allocator_type())
403  : _Hashtable(__l.begin(), __l.end(), __n, __hf, _H2(), _Hash(), __eql,
404  __key_extract(), __a)
405  { }
406 
407  _Hashtable&
408  operator=(const _Hashtable& __ht);
409 
410  _Hashtable&
411  operator=(_Hashtable&& __ht)
412  noexcept(__node_alloc_traits::_S_nothrow_move())
413  {
414  constexpr bool __move_storage =
415  __node_alloc_traits::_S_propagate_on_move_assign()
416  || __node_alloc_traits::_S_always_equal();
417  _M_move_assign(std::move(__ht),
419  return *this;
420  }
421 
422  _Hashtable&
423  operator=(initializer_list<value_type> __l)
424  {
425  __reuse_or_alloc_node_type __roan(_M_begin(), *this);
426  _M_before_begin._M_nxt = nullptr;
427  clear();
428  this->_M_insert_range(__l.begin(), __l.end(), __roan);
429  return *this;
430  }
431 
432  ~_Hashtable() noexcept;
433 
434  void
435  swap(_Hashtable&)
436  noexcept(__node_alloc_traits::_S_nothrow_swap());
437 
438  // Basic container operations
439  iterator
440  begin() noexcept
441  { return iterator(_M_begin()); }
442 
443  const_iterator
444  begin() const noexcept
445  { return const_iterator(_M_begin()); }
446 
447  iterator
448  end() noexcept
449  { return iterator(nullptr); }
450 
451  const_iterator
452  end() const noexcept
453  { return const_iterator(nullptr); }
454 
455  const_iterator
456  cbegin() const noexcept
457  { return const_iterator(_M_begin()); }
458 
459  const_iterator
460  cend() const noexcept
461  { return const_iterator(nullptr); }
462 
463  size_type
464  size() const noexcept
465  { return _M_element_count; }
466 
467  bool
468  empty() const noexcept
469  { return size() == 0; }
470 
471  allocator_type
472  get_allocator() const noexcept
473  { return allocator_type(this->_M_node_allocator()); }
474 
475  size_type
476  max_size() const noexcept
477  { return __node_alloc_traits::max_size(this->_M_node_allocator()); }
478 
479  // Observers
480  key_equal
481  key_eq() const
482  { return this->_M_eq(); }
483 
484  // hash_function, if present, comes from _Hash_code_base.
485 
486  // Bucket operations
487  size_type
488  bucket_count() const noexcept
489  { return _M_bucket_count; }
490 
491  size_type
492  max_bucket_count() const noexcept
493  { return max_size(); }
494 
495  size_type
496  bucket_size(size_type __n) const
497  { return std::distance(begin(__n), end(__n)); }
498 
499  size_type
500  bucket(const key_type& __k) const
501  { return _M_bucket_index(__k, this->_M_hash_code(__k)); }
502 
503  local_iterator
504  begin(size_type __n)
505  {
506  return local_iterator(*this, _M_bucket_begin(__n),
507  __n, _M_bucket_count);
508  }
509 
510  local_iterator
511  end(size_type __n)
512  { return local_iterator(*this, nullptr, __n, _M_bucket_count); }
513 
514  const_local_iterator
515  begin(size_type __n) const
516  {
517  return const_local_iterator(*this, _M_bucket_begin(__n),
518  __n, _M_bucket_count);
519  }
520 
521  const_local_iterator
522  end(size_type __n) const
523  { return const_local_iterator(*this, nullptr, __n, _M_bucket_count); }
524 
525  // DR 691.
526  const_local_iterator
527  cbegin(size_type __n) const
528  {
529  return const_local_iterator(*this, _M_bucket_begin(__n),
530  __n, _M_bucket_count);
531  }
532 
533  const_local_iterator
534  cend(size_type __n) const
535  { return const_local_iterator(*this, nullptr, __n, _M_bucket_count); }
536 
537  float
538  load_factor() const noexcept
539  {
540  return static_cast<float>(size()) / static_cast<float>(bucket_count());
541  }
542 
543  // max_load_factor, if present, comes from _Rehash_base.
544 
545  // Generalization of max_load_factor. Extension, not found in
546  // TR1. Only useful if _RehashPolicy is something other than
547  // the default.
548  const _RehashPolicy&
549  __rehash_policy() const
550  { return _M_rehash_policy; }
551 
552  void
553  __rehash_policy(const _RehashPolicy&);
554 
555  // Lookup.
556  iterator
557  find(const key_type& __k);
558 
559  const_iterator
560  find(const key_type& __k) const;
561 
562  size_type
563  count(const key_type& __k) const;
564 
566  equal_range(const key_type& __k);
567 
569  equal_range(const key_type& __k) const;
570 
571  protected:
572  // Bucket index computation helpers.
573  size_type
574  _M_bucket_index(__node_type* __n) const noexcept
575  { return __hash_code_base::_M_bucket_index(__n, _M_bucket_count); }
576 
577  size_type
578  _M_bucket_index(const key_type& __k, __hash_code __c) const
579  { return __hash_code_base::_M_bucket_index(__k, __c, _M_bucket_count); }
580 
581  // Find and insert helper functions and types
582  // Find the node before the one matching the criteria.
583  __node_base*
584  _M_find_before_node(size_type, const key_type&, __hash_code) const;
585 
586  __node_type*
587  _M_find_node(size_type __bkt, const key_type& __key,
588  __hash_code __c) const
589  {
590  __node_base* __before_n = _M_find_before_node(__bkt, __key, __c);
591  if (__before_n)
592  return static_cast<__node_type*>(__before_n->_M_nxt);
593  return nullptr;
594  }
595 
596  // Insert a node at the beginning of a bucket.
597  void
598  _M_insert_bucket_begin(size_type, __node_type*);
599 
600  // Remove the bucket first node
601  void
602  _M_remove_bucket_begin(size_type __bkt, __node_type* __next_n,
603  size_type __next_bkt);
604 
605  // Get the node before __n in the bucket __bkt
606  __node_base*
607  _M_get_previous_node(size_type __bkt, __node_base* __n);
608 
609  // Insert node with hash code __code, in bucket bkt if no rehash (assumes
610  // no element with its key already present). Take ownership of the node,
611  // deallocate it on exception.
612  iterator
613  _M_insert_unique_node(size_type __bkt, __hash_code __code,
614  __node_type* __n);
615 
616  // Insert node with hash code __code. Take ownership of the node,
617  // deallocate it on exception.
618  iterator
619  _M_insert_multi_node(__node_type* __hint,
620  __hash_code __code, __node_type* __n);
621 
622  template<typename... _Args>
624  _M_emplace(std::true_type, _Args&&... __args);
625 
626  template<typename... _Args>
627  iterator
628  _M_emplace(std::false_type __uk, _Args&&... __args)
629  { return _M_emplace(cend(), __uk, std::forward<_Args>(__args)...); }
630 
631  // Emplace with hint, useless when keys are unique.
632  template<typename... _Args>
633  iterator
634  _M_emplace(const_iterator, std::true_type __uk, _Args&&... __args)
635  { return _M_emplace(__uk, std::forward<_Args>(__args)...).first; }
636 
637  template<typename... _Args>
638  iterator
639  _M_emplace(const_iterator, std::false_type, _Args&&... __args);
640 
641  template<typename _Arg, typename _NodeGenerator>
643  _M_insert(_Arg&&, const _NodeGenerator&, std::true_type);
644 
645  template<typename _Arg, typename _NodeGenerator>
646  iterator
647  _M_insert(_Arg&& __arg, const _NodeGenerator& __node_gen,
648  std::false_type __uk)
649  {
650  return _M_insert(cend(), std::forward<_Arg>(__arg), __node_gen,
651  __uk);
652  }
653 
654  // Insert with hint, not used when keys are unique.
655  template<typename _Arg, typename _NodeGenerator>
656  iterator
657  _M_insert(const_iterator, _Arg&& __arg, const _NodeGenerator& __node_gen,
658  std::true_type __uk)
659  {
660  return
661  _M_insert(std::forward<_Arg>(__arg), __node_gen, __uk).first;
662  }
663 
664  // Insert with hint when keys are not unique.
665  template<typename _Arg, typename _NodeGenerator>
666  iterator
667  _M_insert(const_iterator, _Arg&&, const _NodeGenerator&, std::false_type);
668 
669  size_type
670  _M_erase(std::true_type, const key_type&);
671 
672  size_type
673  _M_erase(std::false_type, const key_type&);
674 
675  iterator
676  _M_erase(size_type __bkt, __node_base* __prev_n, __node_type* __n);
677 
678  public:
679  // Emplace
680  template<typename... _Args>
681  __ireturn_type
682  emplace(_Args&&... __args)
683  { return _M_emplace(__unique_keys(), std::forward<_Args>(__args)...); }
684 
685  template<typename... _Args>
686  iterator
687  emplace_hint(const_iterator __hint, _Args&&... __args)
688  {
689  return _M_emplace(__hint, __unique_keys(),
690  std::forward<_Args>(__args)...);
691  }
692 
693  // Insert member functions via inheritance.
694 
695  // Erase
696  iterator
697  erase(const_iterator);
698 
699  // LWG 2059.
700  iterator
701  erase(iterator __it)
702  { return erase(const_iterator(__it)); }
703 
704  size_type
705  erase(const key_type& __k)
706  {
707  if (__builtin_expect(_M_bucket_count == 0, false))
708  return 0;
709  return _M_erase(__unique_keys(), __k);
710  }
711 
712  iterator
713  erase(const_iterator, const_iterator);
714 
715  void
716  clear() noexcept;
717 
718  // Set number of buckets to be appropriate for container of n element.
719  void rehash(size_type __n);
720 
721  // DR 1189.
722  // reserve, if present, comes from _Rehash_base.
723 
724  private:
725  // Helper rehash method used when keys are unique.
726  void _M_rehash_aux(size_type __n, std::true_type);
727 
728  // Helper rehash method used when keys can be non-unique.
729  void _M_rehash_aux(size_type __n, std::false_type);
730 
731  // Unconditionally change size of bucket array to n, restore
732  // hash policy state to __state on exception.
733  void _M_rehash(size_type __n, const __rehash_state& __state);
734  };
735 
736 
737  // Definitions of class template _Hashtable's out-of-line member functions.
738  template<typename _Key, typename _Value,
739  typename _Alloc, typename _ExtractKey, typename _Equal,
740  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
741  typename _Traits>
742  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
743  _Equal, _H1, _H2, _Hash, _RehashPolicy,
744  _Traits>::__node_type*
745  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
746  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
747  _M_bucket_begin(size_type __bkt) const
748  {
749  __node_base* __n = _M_buckets[__bkt];
750  return __n ? static_cast<__node_type*>(__n->_M_nxt) : nullptr;
751  }
752 
753  template<typename _Key, typename _Value,
754  typename _Alloc, typename _ExtractKey, typename _Equal,
755  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
756  typename _Traits>
757  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
758  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
759  _Hashtable(size_type __bucket_hint,
760  const _H1& __h1, const _H2& __h2, const _Hash& __h,
761  const _Equal& __eq, const _ExtractKey& __exk,
762  const allocator_type& __a)
763  : __hashtable_base(__exk, __h1, __h2, __h, __eq),
764  __map_base(),
765  __rehash_base(),
766  __hashtable_alloc(__node_alloc_type(__a)),
767  _M_element_count(0),
768  _M_rehash_policy()
769  {
770  _M_bucket_count = _M_rehash_policy._M_next_bkt(__bucket_hint);
771  _M_buckets = this->_M_allocate_buckets(_M_bucket_count);
772  }
773 
774  template<typename _Key, typename _Value,
775  typename _Alloc, typename _ExtractKey, typename _Equal,
776  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
777  typename _Traits>
778  template<typename _InputIterator>
779  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
780  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
781  _Hashtable(_InputIterator __f, _InputIterator __l,
782  size_type __bucket_hint,
783  const _H1& __h1, const _H2& __h2, const _Hash& __h,
784  const _Equal& __eq, const _ExtractKey& __exk,
785  const allocator_type& __a)
786  : __hashtable_base(__exk, __h1, __h2, __h, __eq),
787  __map_base(),
788  __rehash_base(),
789  __hashtable_alloc(__node_alloc_type(__a)),
790  _M_element_count(0),
791  _M_rehash_policy()
792  {
793  auto __nb_elems = __detail::__distance_fw(__f, __l);
794  _M_bucket_count =
795  _M_rehash_policy._M_next_bkt(
796  std::max(_M_rehash_policy._M_bkt_for_elements(__nb_elems),
797  __bucket_hint));
798 
799  _M_buckets = this->_M_allocate_buckets(_M_bucket_count);
800  __try
801  {
802  for (; __f != __l; ++__f)
803  this->insert(*__f);
804  }
805  __catch(...)
806  {
807  clear();
808  _M_deallocate_buckets();
809  __throw_exception_again;
810  }
811  }
812 
813  template<typename _Key, typename _Value,
814  typename _Alloc, typename _ExtractKey, typename _Equal,
815  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
816  typename _Traits>
817  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
818  _H1, _H2, _Hash, _RehashPolicy, _Traits>&
819  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
820  _H1, _H2, _Hash, _RehashPolicy, _Traits>::operator=(
821  const _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
822  _H1, _H2, _Hash, _RehashPolicy, _Traits>& __ht)
823  {
824  if (&__ht == this)
825  return *this;
826 
827  if (__node_alloc_traits::_S_propagate_on_copy_assign())
828  {
829  auto& __this_alloc = this->_M_node_allocator();
830  auto& __that_alloc = __ht._M_node_allocator();
831  if (!__node_alloc_traits::_S_always_equal()
832  && __this_alloc != __that_alloc)
833  {
834  // Replacement allocator cannot free existing storage.
835  this->_M_deallocate_nodes(_M_begin());
836  if (__builtin_expect(_M_bucket_count != 0, true))
837  _M_deallocate_buckets();
838  _M_reset();
839  std::__alloc_on_copy(__this_alloc, __that_alloc);
840  __hashtable_base::operator=(__ht);
841  _M_bucket_count = __ht._M_bucket_count;
842  _M_element_count = __ht._M_element_count;
843  _M_rehash_policy = __ht._M_rehash_policy;
844  __try
845  {
846  _M_assign(__ht,
847  [this](const __node_type* __n)
848  { return this->_M_allocate_node(__n->_M_v()); });
849  }
850  __catch(...)
851  {
852  // _M_assign took care of deallocating all memory. Now we
853  // must make sure this instance remains in a usable state.
854  _M_reset();
855  __throw_exception_again;
856  }
857  return *this;
858  }
859  std::__alloc_on_copy(__this_alloc, __that_alloc);
860  }
861 
862  // Reuse allocated buckets and nodes.
863  __bucket_type* __former_buckets = nullptr;
864  std::size_t __former_bucket_count = _M_bucket_count;
865  const __rehash_state& __former_state = _M_rehash_policy._M_state();
866 
867  if (_M_bucket_count != __ht._M_bucket_count)
868  {
869  __former_buckets = _M_buckets;
870  _M_buckets = this->_M_allocate_buckets(__ht._M_bucket_count);
871  _M_bucket_count = __ht._M_bucket_count;
872  }
873  else
874  __builtin_memset(_M_buckets, 0,
875  _M_bucket_count * sizeof(__bucket_type));
876 
877  __try
878  {
879  __hashtable_base::operator=(__ht);
880  _M_element_count = __ht._M_element_count;
881  _M_rehash_policy = __ht._M_rehash_policy;
882  __reuse_or_alloc_node_type __roan(_M_begin(), *this);
883  _M_before_begin._M_nxt = nullptr;
884  _M_assign(__ht,
885  [&__roan](const __node_type* __n)
886  { return __roan(__n->_M_v()); });
887  if (__former_buckets)
888  this->_M_deallocate_buckets(__former_buckets,
889  __former_bucket_count);
890  }
891  __catch(...)
892  {
893  if (__former_buckets)
894  {
895  // Restore previous buckets.
896  _M_deallocate_buckets();
897  _M_rehash_policy._M_reset(__former_state);
898  _M_buckets = __former_buckets;
899  _M_bucket_count = __former_bucket_count;
900  }
901  __builtin_memset(_M_buckets, 0,
902  _M_bucket_count * sizeof(__bucket_type));
903  __throw_exception_again;
904  }
905  return *this;
906  }
907 
908  template<typename _Key, typename _Value,
909  typename _Alloc, typename _ExtractKey, typename _Equal,
910  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
911  typename _Traits>
912  template<typename _NodeGenerator>
913  void
914  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
915  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
916  _M_assign(const _Hashtable& __ht, const _NodeGenerator& __node_gen)
917  {
918  __bucket_type* __buckets = nullptr;
919  if (!_M_buckets)
920  _M_buckets = __buckets = this->_M_allocate_buckets(_M_bucket_count);
921 
922  __try
923  {
924  if (!__ht._M_before_begin._M_nxt)
925  return;
926 
927  // First deal with the special first node pointed to by
928  // _M_before_begin.
929  __node_type* __ht_n = __ht._M_begin();
930  __node_type* __this_n = __node_gen(__ht_n);
931  this->_M_copy_code(__this_n, __ht_n);
932  _M_before_begin._M_nxt = __this_n;
933  _M_buckets[_M_bucket_index(__this_n)] = &_M_before_begin;
934 
935  // Then deal with other nodes.
936  __node_base* __prev_n = __this_n;
937  for (__ht_n = __ht_n->_M_next(); __ht_n; __ht_n = __ht_n->_M_next())
938  {
939  __this_n = __node_gen(__ht_n);
940  __prev_n->_M_nxt = __this_n;
941  this->_M_copy_code(__this_n, __ht_n);
942  size_type __bkt = _M_bucket_index(__this_n);
943  if (!_M_buckets[__bkt])
944  _M_buckets[__bkt] = __prev_n;
945  __prev_n = __this_n;
946  }
947  }
948  __catch(...)
949  {
950  clear();
951  if (__buckets)
952  _M_deallocate_buckets();
953  __throw_exception_again;
954  }
955  }
956 
957  template<typename _Key, typename _Value,
958  typename _Alloc, typename _ExtractKey, typename _Equal,
959  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
960  typename _Traits>
961  void
962  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
963  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
964  _M_reset() noexcept
965  {
966  _M_rehash_policy._M_reset();
967  _M_bucket_count = 0;
968  _M_buckets = nullptr;
969  _M_before_begin._M_nxt = nullptr;
970  _M_element_count = 0;
971  }
972 
973  template<typename _Key, typename _Value,
974  typename _Alloc, typename _ExtractKey, typename _Equal,
975  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
976  typename _Traits>
977  void
978  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
979  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
980  _M_move_assign(_Hashtable&& __ht, std::true_type)
981  {
982  this->_M_deallocate_nodes(_M_begin());
983  if (__builtin_expect(_M_bucket_count != 0, true))
984  _M_deallocate_buckets();
985 
986  __hashtable_base::operator=(std::move(__ht));
987  _M_rehash_policy = __ht._M_rehash_policy;
988  _M_buckets = __ht._M_buckets;
989  _M_bucket_count = __ht._M_bucket_count;
990  _M_before_begin._M_nxt = __ht._M_before_begin._M_nxt;
991  _M_element_count = __ht._M_element_count;
992  std::__alloc_on_move(this->_M_node_allocator(), __ht._M_node_allocator());
993 
994  // Fix buckets containing the _M_before_begin pointers that can't be
995  // moved.
996  if (_M_begin())
997  _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
998  __ht._M_reset();
999  }
1000 
1001  template<typename _Key, typename _Value,
1002  typename _Alloc, typename _ExtractKey, typename _Equal,
1003  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1004  typename _Traits>
1005  void
1006  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1007  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1008  _M_move_assign(_Hashtable&& __ht, std::false_type)
1009  {
1010  if (__ht._M_node_allocator() == this->_M_node_allocator())
1011  _M_move_assign(std::move(__ht), std::true_type());
1012  else
1013  {
1014  // Can't move memory, move elements then.
1015  __bucket_type* __former_buckets = nullptr;
1016  size_type __former_bucket_count = _M_bucket_count;
1017  const __rehash_state& __former_state = _M_rehash_policy._M_state();
1018 
1019  if (_M_bucket_count != __ht._M_bucket_count)
1020  {
1021  __former_buckets = _M_buckets;
1022  _M_buckets = this->_M_allocate_buckets(__ht._M_bucket_count);
1023  _M_bucket_count = __ht._M_bucket_count;
1024  }
1025  else
1026  __builtin_memset(_M_buckets, 0,
1027  _M_bucket_count * sizeof(__bucket_type));
1028 
1029  __try
1030  {
1031  __hashtable_base::operator=(std::move(__ht));
1032  _M_element_count = __ht._M_element_count;
1033  _M_rehash_policy = __ht._M_rehash_policy;
1034  __reuse_or_alloc_node_type __roan(_M_begin(), *this);
1035  _M_before_begin._M_nxt = nullptr;
1036  _M_assign(__ht,
1037  [&__roan](__node_type* __n)
1038  { return __roan(std::move_if_noexcept(__n->_M_v())); });
1039  __ht.clear();
1040  }
1041  __catch(...)
1042  {
1043  if (__former_buckets)
1044  {
1045  _M_deallocate_buckets();
1046  _M_rehash_policy._M_reset(__former_state);
1047  _M_buckets = __former_buckets;
1048  _M_bucket_count = __former_bucket_count;
1049  }
1050  __builtin_memset(_M_buckets, 0,
1051  _M_bucket_count * sizeof(__bucket_type));
1052  __throw_exception_again;
1053  }
1054  }
1055  }
1056 
1057  template<typename _Key, typename _Value,
1058  typename _Alloc, typename _ExtractKey, typename _Equal,
1059  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1060  typename _Traits>
1061  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1062  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1063  _Hashtable(const _Hashtable& __ht)
1064  : __hashtable_base(__ht),
1065  __map_base(__ht),
1066  __rehash_base(__ht),
1067  __hashtable_alloc(
1068  __node_alloc_traits::_S_select_on_copy(__ht._M_node_allocator())),
1069  _M_buckets(),
1070  _M_bucket_count(__ht._M_bucket_count),
1071  _M_element_count(__ht._M_element_count),
1072  _M_rehash_policy(__ht._M_rehash_policy)
1073  {
1074  _M_assign(__ht,
1075  [this](const __node_type* __n)
1076  { return this->_M_allocate_node(__n->_M_v()); });
1077  }
1078 
1079  template<typename _Key, typename _Value,
1080  typename _Alloc, typename _ExtractKey, typename _Equal,
1081  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1082  typename _Traits>
1083  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1084  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1085  _Hashtable(_Hashtable&& __ht) noexcept
1086  : __hashtable_base(__ht),
1087  __map_base(__ht),
1088  __rehash_base(__ht),
1089  __hashtable_alloc(std::move(__ht._M_base_alloc())),
1090  _M_buckets(__ht._M_buckets),
1091  _M_bucket_count(__ht._M_bucket_count),
1092  _M_before_begin(__ht._M_before_begin._M_nxt),
1093  _M_element_count(__ht._M_element_count),
1094  _M_rehash_policy(__ht._M_rehash_policy)
1095  {
1096  // Update, if necessary, bucket pointing to before begin that hasn't
1097  // moved.
1098  if (_M_begin())
1099  _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
1100  __ht._M_reset();
1101  }
1102 
1103  template<typename _Key, typename _Value,
1104  typename _Alloc, typename _ExtractKey, typename _Equal,
1105  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1106  typename _Traits>
1107  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1108  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1109  _Hashtable(const _Hashtable& __ht, const allocator_type& __a)
1110  : __hashtable_base(__ht),
1111  __map_base(__ht),
1112  __rehash_base(__ht),
1113  __hashtable_alloc(__node_alloc_type(__a)),
1114  _M_buckets(),
1115  _M_bucket_count(__ht._M_bucket_count),
1116  _M_element_count(__ht._M_element_count),
1117  _M_rehash_policy(__ht._M_rehash_policy)
1118  {
1119  _M_assign(__ht,
1120  [this](const __node_type* __n)
1121  { return this->_M_allocate_node(__n->_M_v()); });
1122  }
1123 
1124  template<typename _Key, typename _Value,
1125  typename _Alloc, typename _ExtractKey, typename _Equal,
1126  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1127  typename _Traits>
1128  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1129  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1130  _Hashtable(_Hashtable&& __ht, const allocator_type& __a)
1131  : __hashtable_base(__ht),
1132  __map_base(__ht),
1133  __rehash_base(__ht),
1134  __hashtable_alloc(__node_alloc_type(__a)),
1135  _M_buckets(),
1136  _M_bucket_count(__ht._M_bucket_count),
1137  _M_element_count(__ht._M_element_count),
1138  _M_rehash_policy(__ht._M_rehash_policy)
1139  {
1140  if (__ht._M_node_allocator() == this->_M_node_allocator())
1141  {
1142  _M_buckets = __ht._M_buckets;
1143  _M_before_begin._M_nxt = __ht._M_before_begin._M_nxt;
1144  // Update, if necessary, bucket pointing to before begin that hasn't
1145  // moved.
1146  if (_M_begin())
1147  _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
1148  __ht._M_reset();
1149  }
1150  else
1151  {
1152  _M_assign(__ht,
1153  [this](__node_type* __n)
1154  {
1155  return this->_M_allocate_node(
1156  std::move_if_noexcept(__n->_M_v()));
1157  });
1158  __ht.clear();
1159  }
1160  }
1161 
1162  template<typename _Key, typename _Value,
1163  typename _Alloc, typename _ExtractKey, typename _Equal,
1164  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1165  typename _Traits>
1166  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1167  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1168  ~_Hashtable() noexcept
1169  {
1170  clear();
1171  if (_M_buckets)
1172  _M_deallocate_buckets();
1173  }
1174 
1175  template<typename _Key, typename _Value,
1176  typename _Alloc, typename _ExtractKey, typename _Equal,
1177  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1178  typename _Traits>
1179  void
1180  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1181  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1182  swap(_Hashtable& __x)
1183  noexcept(__node_alloc_traits::_S_nothrow_swap())
1184  {
1185  // The only base class with member variables is hash_code_base.
1186  // We define _Hash_code_base::_M_swap because different
1187  // specializations have different members.
1188  this->_M_swap(__x);
1189 
1190  std::__alloc_on_swap(this->_M_node_allocator(), __x._M_node_allocator());
1191  std::swap(_M_rehash_policy, __x._M_rehash_policy);
1192  std::swap(_M_buckets, __x._M_buckets);
1193  std::swap(_M_bucket_count, __x._M_bucket_count);
1194  std::swap(_M_before_begin._M_nxt, __x._M_before_begin._M_nxt);
1195  std::swap(_M_element_count, __x._M_element_count);
1196 
1197  // Fix buckets containing the _M_before_begin pointers that can't be
1198  // swapped.
1199  if (_M_begin())
1200  _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
1201  if (__x._M_begin())
1202  __x._M_buckets[__x._M_bucket_index(__x._M_begin())]
1203  = &__x._M_before_begin;
1204  }
1205 
1206  template<typename _Key, typename _Value,
1207  typename _Alloc, typename _ExtractKey, typename _Equal,
1208  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1209  typename _Traits>
1210  void
1211  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1212  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1213  __rehash_policy(const _RehashPolicy& __pol)
1214  {
1215  size_type __n_bkt = __pol._M_bkt_for_elements(_M_element_count);
1216  __n_bkt = __pol._M_next_bkt(__n_bkt);
1217  if (__n_bkt != _M_bucket_count)
1218  _M_rehash(__n_bkt, _M_rehash_policy._M_state());
1219  _M_rehash_policy = __pol;
1220  }
1221 
1222  template<typename _Key, typename _Value,
1223  typename _Alloc, typename _ExtractKey, typename _Equal,
1224  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1225  typename _Traits>
1226  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1227  _H1, _H2, _Hash, _RehashPolicy,
1228  _Traits>::iterator
1229  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1230  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1231  find(const key_type& __k)
1232  {
1233  if (__builtin_expect(_M_bucket_count == 0, false))
1234  return end();
1235 
1236  __hash_code __code = this->_M_hash_code(__k);
1237  std::size_t __n = _M_bucket_index(__k, __code);
1238  __node_type* __p = _M_find_node(__n, __k, __code);
1239  return __p ? iterator(__p) : end();
1240  }
1241 
1242  template<typename _Key, typename _Value,
1243  typename _Alloc, typename _ExtractKey, typename _Equal,
1244  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1245  typename _Traits>
1246  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1247  _H1, _H2, _Hash, _RehashPolicy,
1248  _Traits>::const_iterator
1249  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1250  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1251  find(const key_type& __k) const
1252  {
1253  if (__builtin_expect(_M_bucket_count == 0, false))
1254  return end();
1255 
1256  __hash_code __code = this->_M_hash_code(__k);
1257  std::size_t __n = _M_bucket_index(__k, __code);
1258  __node_type* __p = _M_find_node(__n, __k, __code);
1259  return __p ? const_iterator(__p) : end();
1260  }
1261 
1262  template<typename _Key, typename _Value,
1263  typename _Alloc, typename _ExtractKey, typename _Equal,
1264  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1265  typename _Traits>
1266  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1267  _H1, _H2, _Hash, _RehashPolicy,
1268  _Traits>::size_type
1269  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1270  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1271  count(const key_type& __k) const
1272  {
1273  if (__builtin_expect(_M_bucket_count == 0, false))
1274  return 0;
1275 
1276  __hash_code __code = this->_M_hash_code(__k);
1277  std::size_t __n = _M_bucket_index(__k, __code);
1278  __node_type* __p = _M_bucket_begin(__n);
1279  if (!__p)
1280  return 0;
1281 
1282  std::size_t __result = 0;
1283  for (;; __p = __p->_M_next())
1284  {
1285  if (this->_M_equals(__k, __code, __p))
1286  ++__result;
1287  else if (__result)
1288  // All equivalent values are next to each other, if we
1289  // found a non-equivalent value after an equivalent one it
1290  // means that we won't find any more equivalent values.
1291  break;
1292  if (!__p->_M_nxt || _M_bucket_index(__p->_M_next()) != __n)
1293  break;
1294  }
1295  return __result;
1296  }
1297 
1298  template<typename _Key, typename _Value,
1299  typename _Alloc, typename _ExtractKey, typename _Equal,
1300  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1301  typename _Traits>
1302  std::pair<typename _Hashtable<_Key, _Value, _Alloc,
1303  _ExtractKey, _Equal, _H1,
1304  _H2, _Hash, _RehashPolicy,
1305  _Traits>::iterator,
1306  typename _Hashtable<_Key, _Value, _Alloc,
1307  _ExtractKey, _Equal, _H1,
1308  _H2, _Hash, _RehashPolicy,
1309  _Traits>::iterator>
1310  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1311  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1312  equal_range(const key_type& __k)
1313  {
1314  if (__builtin_expect(_M_bucket_count == 0, false))
1315  return std::make_pair(end(), end());
1316 
1317  __hash_code __code = this->_M_hash_code(__k);
1318  std::size_t __n = _M_bucket_index(__k, __code);
1319  __node_type* __p = _M_find_node(__n, __k, __code);
1320 
1321  if (__p)
1322  {
1323  __node_type* __p1 = __p->_M_next();
1324  while (__p1 && _M_bucket_index(__p1) == __n
1325  && this->_M_equals(__k, __code, __p1))
1326  __p1 = __p1->_M_next();
1327 
1328  return std::make_pair(iterator(__p), iterator(__p1));
1329  }
1330  else
1331  return std::make_pair(end(), end());
1332  }
1333 
1334  template<typename _Key, typename _Value,
1335  typename _Alloc, typename _ExtractKey, typename _Equal,
1336  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1337  typename _Traits>
1338  std::pair<typename _Hashtable<_Key, _Value, _Alloc,
1339  _ExtractKey, _Equal, _H1,
1340  _H2, _Hash, _RehashPolicy,
1341  _Traits>::const_iterator,
1342  typename _Hashtable<_Key, _Value, _Alloc,
1343  _ExtractKey, _Equal, _H1,
1344  _H2, _Hash, _RehashPolicy,
1345  _Traits>::const_iterator>
1346  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1347  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1348  equal_range(const key_type& __k) const
1349  {
1350  if (__builtin_expect(_M_bucket_count == 0, false))
1351  return std::make_pair(end(), end());
1352 
1353  __hash_code __code = this->_M_hash_code(__k);
1354  std::size_t __n = _M_bucket_index(__k, __code);
1355  __node_type* __p = _M_find_node(__n, __k, __code);
1356 
1357  if (__p)
1358  {
1359  __node_type* __p1 = __p->_M_next();
1360  while (__p1 && _M_bucket_index(__p1) == __n
1361  && this->_M_equals(__k, __code, __p1))
1362  __p1 = __p1->_M_next();
1363 
1364  return std::make_pair(const_iterator(__p), const_iterator(__p1));
1365  }
1366  else
1367  return std::make_pair(end(), end());
1368  }
1369 
1370  // Find the node whose key compares equal to k in the bucket n.
1371  // Return nullptr if no node is found.
1372  template<typename _Key, typename _Value,
1373  typename _Alloc, typename _ExtractKey, typename _Equal,
1374  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1375  typename _Traits>
1376  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
1377  _Equal, _H1, _H2, _Hash, _RehashPolicy,
1378  _Traits>::__node_base*
1379  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1380  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1381  _M_find_before_node(size_type __n, const key_type& __k,
1382  __hash_code __code) const
1383  {
1384  __node_base* __prev_p = _M_buckets[__n];
1385  if (!__prev_p)
1386  return nullptr;
1387 
1388  for (__node_type* __p = static_cast<__node_type*>(__prev_p->_M_nxt);;
1389  __p = __p->_M_next())
1390  {
1391  if (this->_M_equals(__k, __code, __p))
1392  return __prev_p;
1393 
1394  if (!__p->_M_nxt || _M_bucket_index(__p->_M_next()) != __n)
1395  break;
1396  __prev_p = __p;
1397  }
1398  return nullptr;
1399  }
1400 
1401  template<typename _Key, typename _Value,
1402  typename _Alloc, typename _ExtractKey, typename _Equal,
1403  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1404  typename _Traits>
1405  void
1406  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1407  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1408  _M_insert_bucket_begin(size_type __bkt, __node_type* __node)
1409  {
1410  if (_M_buckets[__bkt])
1411  {
1412  // Bucket is not empty, we just need to insert the new node
1413  // after the bucket before begin.
1414  __node->_M_nxt = _M_buckets[__bkt]->_M_nxt;
1415  _M_buckets[__bkt]->_M_nxt = __node;
1416  }
1417  else
1418  {
1419  // The bucket is empty, the new node is inserted at the
1420  // beginning of the singly-linked list and the bucket will
1421  // contain _M_before_begin pointer.
1422  __node->_M_nxt = _M_before_begin._M_nxt;
1423  _M_before_begin._M_nxt = __node;
1424  if (__node->_M_nxt)
1425  // We must update former begin bucket that is pointing to
1426  // _M_before_begin.
1427  _M_buckets[_M_bucket_index(__node->_M_next())] = __node;
1428  _M_buckets[__bkt] = &_M_before_begin;
1429  }
1430  }
1431 
1432  template<typename _Key, typename _Value,
1433  typename _Alloc, typename _ExtractKey, typename _Equal,
1434  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1435  typename _Traits>
1436  void
1437  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1438  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1439  _M_remove_bucket_begin(size_type __bkt, __node_type* __next,
1440  size_type __next_bkt)
1441  {
1442  if (!__next || __next_bkt != __bkt)
1443  {
1444  // Bucket is now empty
1445  // First update next bucket if any
1446  if (__next)
1447  _M_buckets[__next_bkt] = _M_buckets[__bkt];
1448 
1449  // Second update before begin node if necessary
1450  if (&_M_before_begin == _M_buckets[__bkt])
1451  _M_before_begin._M_nxt = __next;
1452  _M_buckets[__bkt] = nullptr;
1453  }
1454  }
1455 
1456  template<typename _Key, typename _Value,
1457  typename _Alloc, typename _ExtractKey, typename _Equal,
1458  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1459  typename _Traits>
1460  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
1461  _Equal, _H1, _H2, _Hash, _RehashPolicy,
1462  _Traits>::__node_base*
1463  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1464  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1465  _M_get_previous_node(size_type __bkt, __node_base* __n)
1466  {
1467  __node_base* __prev_n = _M_buckets[__bkt];
1468  while (__prev_n->_M_nxt != __n)
1469  __prev_n = __prev_n->_M_nxt;
1470  return __prev_n;
1471  }
1472 
1473  template<typename _Key, typename _Value,
1474  typename _Alloc, typename _ExtractKey, typename _Equal,
1475  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1476  typename _Traits>
1477  template<typename... _Args>
1478  std::pair<typename _Hashtable<_Key, _Value, _Alloc,
1479  _ExtractKey, _Equal, _H1,
1480  _H2, _Hash, _RehashPolicy,
1481  _Traits>::iterator, bool>
1482  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1483  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1484  _M_emplace(std::true_type, _Args&&... __args)
1485  {
1486  // First build the node to get access to the hash code
1487  __node_type* __node = this->_M_allocate_node(std::forward<_Args>(__args)...);
1488  const key_type& __k = this->_M_extract()(__node->_M_v());
1489  __hash_code __code;
1490  __try
1491  {
1492  __code = this->_M_hash_code(__k);
1493  }
1494  __catch(...)
1495  {
1496  this->_M_deallocate_node(__node);
1497  __throw_exception_again;
1498  }
1499 
1500  size_type __bkt = _M_bucket_index(__k, __code);
1501  if (__node_type* __p = _M_find_node(__bkt, __k, __code))
1502  {
1503  // There is already an equivalent node, no insertion
1504  this->_M_deallocate_node(__node);
1505  return std::make_pair(iterator(__p), false);
1506  }
1507 
1508  // Insert the node
1509  return std::make_pair(_M_insert_unique_node(__bkt, __code, __node),
1510  true);
1511  }
1512 
1513  template<typename _Key, typename _Value,
1514  typename _Alloc, typename _ExtractKey, typename _Equal,
1515  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1516  typename _Traits>
1517  template<typename... _Args>
1518  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1519  _H1, _H2, _Hash, _RehashPolicy,
1520  _Traits>::iterator
1521  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1522  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1523  _M_emplace(const_iterator __hint, std::false_type, _Args&&... __args)
1524  {
1525  // First build the node to get its hash code.
1526  __node_type* __node =
1527  this->_M_allocate_node(std::forward<_Args>(__args)...);
1528 
1529  __hash_code __code;
1530  __try
1531  {
1532  __code = this->_M_hash_code(this->_M_extract()(__node->_M_v()));
1533  }
1534  __catch(...)
1535  {
1536  this->_M_deallocate_node(__node);
1537  __throw_exception_again;
1538  }
1539 
1540  return _M_insert_multi_node(__hint._M_cur, __code, __node);
1541  }
1542 
1543  template<typename _Key, typename _Value,
1544  typename _Alloc, typename _ExtractKey, typename _Equal,
1545  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1546  typename _Traits>
1547  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1548  _H1, _H2, _Hash, _RehashPolicy,
1549  _Traits>::iterator
1550  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1551  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1552  _M_insert_unique_node(size_type __bkt, __hash_code __code,
1553  __node_type* __node)
1554  {
1555  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
1556  std::pair<bool, std::size_t> __do_rehash
1557  = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count, 1);
1558 
1559  __try
1560  {
1561  if (__do_rehash.first)
1562  {
1563  _M_rehash(__do_rehash.second, __saved_state);
1564  __bkt = _M_bucket_index(this->_M_extract()(__node->_M_v()), __code);
1565  }
1566 
1567  this->_M_store_code(__node, __code);
1568 
1569  // Always insert at the beginning of the bucket.
1570  _M_insert_bucket_begin(__bkt, __node);
1571  ++_M_element_count;
1572  return iterator(__node);
1573  }
1574  __catch(...)
1575  {
1576  this->_M_deallocate_node(__node);
1577  __throw_exception_again;
1578  }
1579  }
1580 
1581  // Insert node, in bucket bkt if no rehash (assumes no element with its key
1582  // already present). Take ownership of the node, deallocate it on exception.
1583  template<typename _Key, typename _Value,
1584  typename _Alloc, typename _ExtractKey, typename _Equal,
1585  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1586  typename _Traits>
1587  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1588  _H1, _H2, _Hash, _RehashPolicy,
1589  _Traits>::iterator
1590  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1591  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1592  _M_insert_multi_node(__node_type* __hint, __hash_code __code,
1593  __node_type* __node)
1594  {
1595  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
1596  std::pair<bool, std::size_t> __do_rehash
1597  = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count, 1);
1598 
1599  __try
1600  {
1601  if (__do_rehash.first)
1602  _M_rehash(__do_rehash.second, __saved_state);
1603 
1604  this->_M_store_code(__node, __code);
1605  const key_type& __k = this->_M_extract()(__node->_M_v());
1606  size_type __bkt = _M_bucket_index(__k, __code);
1607 
1608  // Find the node before an equivalent one or use hint if it exists and
1609  // if it is equivalent.
1610  __node_base* __prev
1611  = __builtin_expect(__hint != nullptr, false)
1612  && this->_M_equals(__k, __code, __hint)
1613  ? __hint
1614  : _M_find_before_node(__bkt, __k, __code);
1615  if (__prev)
1616  {
1617  // Insert after the node before the equivalent one.
1618  __node->_M_nxt = __prev->_M_nxt;
1619  __prev->_M_nxt = __node;
1620  if (__builtin_expect(__prev == __hint, false))
1621  // hint might be the last bucket node, in this case we need to
1622  // update next bucket.
1623  if (__node->_M_nxt
1624  && !this->_M_equals(__k, __code, __node->_M_next()))
1625  {
1626  size_type __next_bkt = _M_bucket_index(__node->_M_next());
1627  if (__next_bkt != __bkt)
1628  _M_buckets[__next_bkt] = __node;
1629  }
1630  }
1631  else
1632  // The inserted node has no equivalent in the
1633  // hashtable. We must insert the new node at the
1634  // beginning of the bucket to preserve equivalent
1635  // elements' relative positions.
1636  _M_insert_bucket_begin(__bkt, __node);
1637  ++_M_element_count;
1638  return iterator(__node);
1639  }
1640  __catch(...)
1641  {
1642  this->_M_deallocate_node(__node);
1643  __throw_exception_again;
1644  }
1645  }
1646 
1647  // Insert v if no element with its key is already present.
1648  template<typename _Key, typename _Value,
1649  typename _Alloc, typename _ExtractKey, typename _Equal,
1650  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1651  typename _Traits>
1652  template<typename _Arg, typename _NodeGenerator>
1653  std::pair<typename _Hashtable<_Key, _Value, _Alloc,
1654  _ExtractKey, _Equal, _H1,
1655  _H2, _Hash, _RehashPolicy,
1656  _Traits>::iterator, bool>
1657  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1658  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1659  _M_insert(_Arg&& __v, const _NodeGenerator& __node_gen, std::true_type)
1660  {
1661  const key_type& __k = this->_M_extract()(__v);
1662  __hash_code __code = this->_M_hash_code(__k);
1663  size_type __bkt = _M_bucket_index(__k, __code);
1664 
1665  __node_type* __n = _M_find_node(__bkt, __k, __code);
1666  if (__n)
1667  return std::make_pair(iterator(__n), false);
1668 
1669  __n = __node_gen(std::forward<_Arg>(__v));
1670  return std::make_pair(_M_insert_unique_node(__bkt, __code, __n), true);
1671  }
1672 
1673  // Insert v unconditionally.
1674  template<typename _Key, typename _Value,
1675  typename _Alloc, typename _ExtractKey, typename _Equal,
1676  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1677  typename _Traits>
1678  template<typename _Arg, typename _NodeGenerator>
1679  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1680  _H1, _H2, _Hash, _RehashPolicy,
1681  _Traits>::iterator
1682  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1683  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1684  _M_insert(const_iterator __hint, _Arg&& __v,
1685  const _NodeGenerator& __node_gen,
1687  {
1688  // First compute the hash code so that we don't do anything if it
1689  // throws.
1690  __hash_code __code = this->_M_hash_code(this->_M_extract()(__v));
1691 
1692  // Second allocate new node so that we don't rehash if it throws.
1693  __node_type* __node = __node_gen(std::forward<_Arg>(__v));
1694 
1695  return _M_insert_multi_node(__hint._M_cur, __code, __node);
1696  }
1697 
1698  template<typename _Key, typename _Value,
1699  typename _Alloc, typename _ExtractKey, typename _Equal,
1700  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1701  typename _Traits>
1702  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1703  _H1, _H2, _Hash, _RehashPolicy,
1704  _Traits>::iterator
1705  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1706  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1707  erase(const_iterator __it)
1708  {
1709  __node_type* __n = __it._M_cur;
1710  std::size_t __bkt = _M_bucket_index(__n);
1711 
1712  // Look for previous node to unlink it from the erased one, this
1713  // is why we need buckets to contain the before begin to make
1714  // this search fast.
1715  __node_base* __prev_n = _M_get_previous_node(__bkt, __n);
1716  return _M_erase(__bkt, __prev_n, __n);
1717  }
1718 
1719  template<typename _Key, typename _Value,
1720  typename _Alloc, typename _ExtractKey, typename _Equal,
1721  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1722  typename _Traits>
1723  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1724  _H1, _H2, _Hash, _RehashPolicy,
1725  _Traits>::iterator
1726  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1727  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1728  _M_erase(size_type __bkt, __node_base* __prev_n, __node_type* __n)
1729  {
1730  if (__prev_n == _M_buckets[__bkt])
1731  _M_remove_bucket_begin(__bkt, __n->_M_next(),
1732  __n->_M_nxt ? _M_bucket_index(__n->_M_next()) : 0);
1733  else if (__n->_M_nxt)
1734  {
1735  size_type __next_bkt = _M_bucket_index(__n->_M_next());
1736  if (__next_bkt != __bkt)
1737  _M_buckets[__next_bkt] = __prev_n;
1738  }
1739 
1740  __prev_n->_M_nxt = __n->_M_nxt;
1741  iterator __result(__n->_M_next());
1742  this->_M_deallocate_node(__n);
1743  --_M_element_count;
1744 
1745  return __result;
1746  }
1747 
1748  template<typename _Key, typename _Value,
1749  typename _Alloc, typename _ExtractKey, typename _Equal,
1750  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1751  typename _Traits>
1752  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1753  _H1, _H2, _Hash, _RehashPolicy,
1754  _Traits>::size_type
1755  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1756  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1757  _M_erase(std::true_type, const key_type& __k)
1758  {
1759  __hash_code __code = this->_M_hash_code(__k);
1760  std::size_t __bkt = _M_bucket_index(__k, __code);
1761 
1762  // Look for the node before the first matching node.
1763  __node_base* __prev_n = _M_find_before_node(__bkt, __k, __code);
1764  if (!__prev_n)
1765  return 0;
1766 
1767  // We found a matching node, erase it.
1768  __node_type* __n = static_cast<__node_type*>(__prev_n->_M_nxt);
1769  _M_erase(__bkt, __prev_n, __n);
1770  return 1;
1771  }
1772 
1773  template<typename _Key, typename _Value,
1774  typename _Alloc, typename _ExtractKey, typename _Equal,
1775  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1776  typename _Traits>
1777  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1778  _H1, _H2, _Hash, _RehashPolicy,
1779  _Traits>::size_type
1780  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1781  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1782  _M_erase(std::false_type, const key_type& __k)
1783  {
1784  __hash_code __code = this->_M_hash_code(__k);
1785  std::size_t __bkt = _M_bucket_index(__k, __code);
1786 
1787  // Look for the node before the first matching node.
1788  __node_base* __prev_n = _M_find_before_node(__bkt, __k, __code);
1789  if (!__prev_n)
1790  return 0;
1791 
1792  // _GLIBCXX_RESOLVE_LIB_DEFECTS
1793  // 526. Is it undefined if a function in the standard changes
1794  // in parameters?
1795  // We use one loop to find all matching nodes and another to deallocate
1796  // them so that the key stays valid during the first loop. It might be
1797  // invalidated indirectly when destroying nodes.
1798  __node_type* __n = static_cast<__node_type*>(__prev_n->_M_nxt);
1799  __node_type* __n_last = __n;
1800  std::size_t __n_last_bkt = __bkt;
1801  do
1802  {
1803  __n_last = __n_last->_M_next();
1804  if (!__n_last)
1805  break;
1806  __n_last_bkt = _M_bucket_index(__n_last);
1807  }
1808  while (__n_last_bkt == __bkt && this->_M_equals(__k, __code, __n_last));
1809 
1810  // Deallocate nodes.
1811  size_type __result = 0;
1812  do
1813  {
1814  __node_type* __p = __n->_M_next();
1815  this->_M_deallocate_node(__n);
1816  __n = __p;
1817  ++__result;
1818  --_M_element_count;
1819  }
1820  while (__n != __n_last);
1821 
1822  if (__prev_n == _M_buckets[__bkt])
1823  _M_remove_bucket_begin(__bkt, __n_last, __n_last_bkt);
1824  else if (__n_last && __n_last_bkt != __bkt)
1825  _M_buckets[__n_last_bkt] = __prev_n;
1826  __prev_n->_M_nxt = __n_last;
1827  return __result;
1828  }
1829 
1830  template<typename _Key, typename _Value,
1831  typename _Alloc, typename _ExtractKey, typename _Equal,
1832  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1833  typename _Traits>
1834  typename _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1835  _H1, _H2, _Hash, _RehashPolicy,
1836  _Traits>::iterator
1837  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1838  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1839  erase(const_iterator __first, const_iterator __last)
1840  {
1841  __node_type* __n = __first._M_cur;
1842  __node_type* __last_n = __last._M_cur;
1843  if (__n == __last_n)
1844  return iterator(__n);
1845 
1846  std::size_t __bkt = _M_bucket_index(__n);
1847 
1848  __node_base* __prev_n = _M_get_previous_node(__bkt, __n);
1849  bool __is_bucket_begin = __n == _M_bucket_begin(__bkt);
1850  std::size_t __n_bkt = __bkt;
1851  for (;;)
1852  {
1853  do
1854  {
1855  __node_type* __tmp = __n;
1856  __n = __n->_M_next();
1857  this->_M_deallocate_node(__tmp);
1858  --_M_element_count;
1859  if (!__n)
1860  break;
1861  __n_bkt = _M_bucket_index(__n);
1862  }
1863  while (__n != __last_n && __n_bkt == __bkt);
1864  if (__is_bucket_begin)
1865  _M_remove_bucket_begin(__bkt, __n, __n_bkt);
1866  if (__n == __last_n)
1867  break;
1868  __is_bucket_begin = true;
1869  __bkt = __n_bkt;
1870  }
1871 
1872  if (__n && (__n_bkt != __bkt || __is_bucket_begin))
1873  _M_buckets[__n_bkt] = __prev_n;
1874  __prev_n->_M_nxt = __n;
1875  return iterator(__n);
1876  }
1877 
1878  template<typename _Key, typename _Value,
1879  typename _Alloc, typename _ExtractKey, typename _Equal,
1880  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1881  typename _Traits>
1882  void
1883  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1884  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1885  clear() noexcept
1886  {
1887  this->_M_deallocate_nodes(_M_begin());
1888  __builtin_memset(_M_buckets, 0, _M_bucket_count * sizeof(__bucket_type));
1889  _M_element_count = 0;
1890  _M_before_begin._M_nxt = nullptr;
1891  }
1892 
1893  template<typename _Key, typename _Value,
1894  typename _Alloc, typename _ExtractKey, typename _Equal,
1895  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1896  typename _Traits>
1897  void
1898  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1899  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1900  rehash(size_type __n)
1901  {
1902  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
1903  std::size_t __buckets
1904  = std::max(_M_rehash_policy._M_bkt_for_elements(_M_element_count + 1),
1905  __n);
1906  __buckets = _M_rehash_policy._M_next_bkt(__buckets);
1907 
1908  if (__buckets != _M_bucket_count)
1909  _M_rehash(__buckets, __saved_state);
1910  else
1911  // No rehash, restore previous state to keep a consistent state.
1912  _M_rehash_policy._M_reset(__saved_state);
1913  }
1914 
1915  template<typename _Key, typename _Value,
1916  typename _Alloc, typename _ExtractKey, typename _Equal,
1917  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1918  typename _Traits>
1919  void
1920  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1921  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1922  _M_rehash(size_type __n, const __rehash_state& __state)
1923  {
1924  __try
1925  {
1926  _M_rehash_aux(__n, __unique_keys());
1927  }
1928  __catch(...)
1929  {
1930  // A failure here means that buckets allocation failed. We only
1931  // have to restore hash policy previous state.
1932  _M_rehash_policy._M_reset(__state);
1933  __throw_exception_again;
1934  }
1935  }
1936 
1937  // Rehash when there is no equivalent elements.
1938  template<typename _Key, typename _Value,
1939  typename _Alloc, typename _ExtractKey, typename _Equal,
1940  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1941  typename _Traits>
1942  void
1943  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1944  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1945  _M_rehash_aux(size_type __n, std::true_type)
1946  {
1947  __bucket_type* __new_buckets = this->_M_allocate_buckets(__n);
1948  __node_type* __p = _M_begin();
1949  _M_before_begin._M_nxt = nullptr;
1950  std::size_t __bbegin_bkt = 0;
1951  while (__p)
1952  {
1953  __node_type* __next = __p->_M_next();
1954  std::size_t __bkt = __hash_code_base::_M_bucket_index(__p, __n);
1955  if (!__new_buckets[__bkt])
1956  {
1957  __p->_M_nxt = _M_before_begin._M_nxt;
1958  _M_before_begin._M_nxt = __p;
1959  __new_buckets[__bkt] = &_M_before_begin;
1960  if (__p->_M_nxt)
1961  __new_buckets[__bbegin_bkt] = __p;
1962  __bbegin_bkt = __bkt;
1963  }
1964  else
1965  {
1966  __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
1967  __new_buckets[__bkt]->_M_nxt = __p;
1968  }
1969  __p = __next;
1970  }
1971 
1972  if (__builtin_expect(_M_bucket_count != 0, true))
1973  _M_deallocate_buckets();
1974  _M_bucket_count = __n;
1975  _M_buckets = __new_buckets;
1976  }
1977 
1978  // Rehash when there can be equivalent elements, preserve their relative
1979  // order.
1980  template<typename _Key, typename _Value,
1981  typename _Alloc, typename _ExtractKey, typename _Equal,
1982  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1983  typename _Traits>
1984  void
1985  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1986  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1987  _M_rehash_aux(size_type __n, std::false_type)
1988  {
1989  __bucket_type* __new_buckets = this->_M_allocate_buckets(__n);
1990 
1991  __node_type* __p = _M_begin();
1992  _M_before_begin._M_nxt = nullptr;
1993  std::size_t __bbegin_bkt = 0;
1994  std::size_t __prev_bkt = 0;
1995  __node_type* __prev_p = nullptr;
1996  bool __check_bucket = false;
1997 
1998  while (__p)
1999  {
2000  __node_type* __next = __p->_M_next();
2001  std::size_t __bkt = __hash_code_base::_M_bucket_index(__p, __n);
2002 
2003  if (__prev_p && __prev_bkt == __bkt)
2004  {
2005  // Previous insert was already in this bucket, we insert after
2006  // the previously inserted one to preserve equivalent elements
2007  // relative order.
2008  __p->_M_nxt = __prev_p->_M_nxt;
2009  __prev_p->_M_nxt = __p;
2010 
2011  // Inserting after a node in a bucket require to check that we
2012  // haven't change the bucket last node, in this case next
2013  // bucket containing its before begin node must be updated. We
2014  // schedule a check as soon as we move out of the sequence of
2015  // equivalent nodes to limit the number of checks.
2016  __check_bucket = true;
2017  }
2018  else
2019  {
2020  if (__check_bucket)
2021  {
2022  // Check if we shall update the next bucket because of
2023  // insertions into __prev_bkt bucket.
2024  if (__prev_p->_M_nxt)
2025  {
2026  std::size_t __next_bkt
2027  = __hash_code_base::_M_bucket_index(__prev_p->_M_next(),
2028  __n);
2029  if (__next_bkt != __prev_bkt)
2030  __new_buckets[__next_bkt] = __prev_p;
2031  }
2032  __check_bucket = false;
2033  }
2034 
2035  if (!__new_buckets[__bkt])
2036  {
2037  __p->_M_nxt = _M_before_begin._M_nxt;
2038  _M_before_begin._M_nxt = __p;
2039  __new_buckets[__bkt] = &_M_before_begin;
2040  if (__p->_M_nxt)
2041  __new_buckets[__bbegin_bkt] = __p;
2042  __bbegin_bkt = __bkt;
2043  }
2044  else
2045  {
2046  __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
2047  __new_buckets[__bkt]->_M_nxt = __p;
2048  }
2049  }
2050  __prev_p = __p;
2051  __prev_bkt = __bkt;
2052  __p = __next;
2053  }
2054 
2055  if (__check_bucket && __prev_p->_M_nxt)
2056  {
2057  std::size_t __next_bkt
2058  = __hash_code_base::_M_bucket_index(__prev_p->_M_next(), __n);
2059  if (__next_bkt != __prev_bkt)
2060  __new_buckets[__next_bkt] = __prev_p;
2061  }
2062 
2063  if (__builtin_expect(_M_bucket_count != 0, true))
2064  _M_deallocate_buckets();
2065  _M_bucket_count = __n;
2066  _M_buckets = __new_buckets;
2067  }
2068 
2069 _GLIBCXX_END_NAMESPACE_VERSION
2070 } // namespace std
2071 
2072 #endif // _HASHTABLE_H
Uniform interface to C++98 and C++0x allocators.
constexpr pair< typename __decay_and_strip< _T1 >::__type, typename __decay_and_strip< _T2 >::__type > make_pair(_T1 &&__x, _T2 &&__y)
A convenience wrapper for creating a pair from two objects.
Definition: stl_pair.h:276
_T2 second
first is a copy of the first object
Definition: stl_pair.h:102
constexpr const _Tp * begin(initializer_list< _Tp > __ils) noexcept
Return an iterator pointing to the first element of the initializer_list.
constexpr size_t size() const noexcept
Returns the total number of bits.
Definition: bitset:1293
Node iterators, used to iterate through all the hashtable.
iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:217
_T1 first
second_type is the second bound type
Definition: stl_pair.h:101
integral_constant
Definition: type_traits:57
size_t count() const noexcept
Returns the number of bits which are set.
Definition: bitset:1288
initializer_list
Uniform interface to all allocator types.
Node const_iterators, used to iterate through all the hashtable.
Struct holding two objects of arbitrary type.
Definition: stl_pair.h:96
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:72
constexpr const _Tp * end(initializer_list< _Tp > __ils) noexcept
Return an iterator pointing to one past the last element of the initializer_list. ...
constexpr conditional< __move_if_noexcept_cond< _Tp >::value, const _Tp &, _Tp && >::type move_if_noexcept(_Tp &__x) noexcept
Conditionally convert a value to an rvalue.
Definition: move.h:121