libstdc++
bits/hashtable.h
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1 // hashtable.h header -*- C++ -*-
2 
3 // Copyright (C) 2007-2015 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
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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 
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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 
226  using __hashtable_base = __detail::
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::
310  const_local_iterator;
311 
312  private:
313  __bucket_type* _M_buckets = &_M_single_bucket;
314  size_type _M_bucket_count = 1;
315  __node_base _M_before_begin;
316  size_type _M_element_count = 0;
317  _RehashPolicy _M_rehash_policy;
318 
319  // A single bucket used when only need for 1 bucket. Especially
320  // interesting in move semantic to leave hashtable with only 1 buckets
321  // which is not allocated so that we can have those operations noexcept
322  // qualified.
323  // Note that we can't leave hashtable with 0 bucket without adding
324  // numerous checks in the code to avoid 0 modulus.
325  __bucket_type _M_single_bucket = nullptr;
326 
327  bool
328  _M_uses_single_bucket(__bucket_type* __bkts) const
329  { return __builtin_expect(__bkts == &_M_single_bucket, false); }
330 
331  bool
332  _M_uses_single_bucket() const
333  { return _M_uses_single_bucket(_M_buckets); }
334 
336  _M_base_alloc() { return *this; }
337 
338  __bucket_type*
339  _M_allocate_buckets(size_type __n)
340  {
341  if (__builtin_expect(__n == 1, false))
342  {
343  _M_single_bucket = nullptr;
344  return &_M_single_bucket;
345  }
346 
347  return __hashtable_alloc::_M_allocate_buckets(__n);
348  }
349 
350  void
351  _M_deallocate_buckets(__bucket_type* __bkts, size_type __n)
352  {
353  if (_M_uses_single_bucket(__bkts))
354  return;
355 
356  __hashtable_alloc::_M_deallocate_buckets(__bkts, __n);
357  }
358 
359  void
360  _M_deallocate_buckets()
361  { _M_deallocate_buckets(_M_buckets, _M_bucket_count); }
362 
363  // Gets bucket begin, deals with the fact that non-empty buckets contain
364  // their before begin node.
365  __node_type*
366  _M_bucket_begin(size_type __bkt) const;
367 
368  __node_type*
369  _M_begin() const
370  { return static_cast<__node_type*>(_M_before_begin._M_nxt); }
371 
372  template<typename _NodeGenerator>
373  void
374  _M_assign(const _Hashtable&, const _NodeGenerator&);
375 
376  void
377  _M_move_assign(_Hashtable&&, std::true_type);
378 
379  void
380  _M_move_assign(_Hashtable&&, std::false_type);
381 
382  void
383  _M_reset() noexcept;
384 
385  _Hashtable(const _H1& __h1, const _H2& __h2, const _Hash& __h,
386  const _Equal& __eq, const _ExtractKey& __exk,
387  const allocator_type& __a)
388  : __hashtable_base(__exk, __h1, __h2, __h, __eq),
389  __hashtable_alloc(__node_alloc_type(__a))
390  { }
391 
392  public:
393  // Constructor, destructor, assignment, swap
394  _Hashtable() = default;
395  _Hashtable(size_type __bucket_hint,
396  const _H1&, const _H2&, const _Hash&,
397  const _Equal&, const _ExtractKey&,
398  const allocator_type&);
399 
400  template<typename _InputIterator>
401  _Hashtable(_InputIterator __first, _InputIterator __last,
402  size_type __bucket_hint,
403  const _H1&, const _H2&, const _Hash&,
404  const _Equal&, const _ExtractKey&,
405  const allocator_type&);
406 
407  _Hashtable(const _Hashtable&);
408 
409  _Hashtable(_Hashtable&&) noexcept;
410 
411  _Hashtable(const _Hashtable&, const allocator_type&);
412 
413  _Hashtable(_Hashtable&&, const allocator_type&);
414 
415  // Use delegating constructors.
416  explicit
417  _Hashtable(const allocator_type& __a)
418  : __hashtable_alloc(__node_alloc_type(__a))
419  { }
420 
421  explicit
422  _Hashtable(size_type __n,
423  const _H1& __hf = _H1(),
424  const key_equal& __eql = key_equal(),
425  const allocator_type& __a = allocator_type())
426  : _Hashtable(__n, __hf, _H2(), _Hash(), __eql,
427  __key_extract(), __a)
428  { }
429 
430  template<typename _InputIterator>
431  _Hashtable(_InputIterator __f, _InputIterator __l,
432  size_type __n = 0,
433  const _H1& __hf = _H1(),
434  const key_equal& __eql = key_equal(),
435  const allocator_type& __a = allocator_type())
436  : _Hashtable(__f, __l, __n, __hf, _H2(), _Hash(), __eql,
437  __key_extract(), __a)
438  { }
439 
441  size_type __n = 0,
442  const _H1& __hf = _H1(),
443  const key_equal& __eql = key_equal(),
444  const allocator_type& __a = allocator_type())
445  : _Hashtable(__l.begin(), __l.end(), __n, __hf, _H2(), _Hash(), __eql,
446  __key_extract(), __a)
447  { }
448 
449  _Hashtable&
450  operator=(const _Hashtable& __ht);
451 
452  _Hashtable&
453  operator=(_Hashtable&& __ht)
454  noexcept(__node_alloc_traits::_S_nothrow_move())
455  {
456  constexpr bool __move_storage =
457  __node_alloc_traits::_S_propagate_on_move_assign()
458  || __node_alloc_traits::_S_always_equal();
459  _M_move_assign(std::move(__ht),
461  return *this;
462  }
463 
464  _Hashtable&
465  operator=(initializer_list<value_type> __l)
466  {
467  __reuse_or_alloc_node_type __roan(_M_begin(), *this);
468  _M_before_begin._M_nxt = nullptr;
469  clear();
470  this->_M_insert_range(__l.begin(), __l.end(), __roan);
471  return *this;
472  }
473 
474  ~_Hashtable() noexcept;
475 
476  void
477  swap(_Hashtable&)
478  noexcept(__node_alloc_traits::_S_nothrow_swap());
479 
480  // Basic container operations
481  iterator
482  begin() noexcept
483  { return iterator(_M_begin()); }
484 
485  const_iterator
486  begin() const noexcept
487  { return const_iterator(_M_begin()); }
488 
489  iterator
490  end() noexcept
491  { return iterator(nullptr); }
492 
493  const_iterator
494  end() const noexcept
495  { return const_iterator(nullptr); }
496 
497  const_iterator
498  cbegin() const noexcept
499  { return const_iterator(_M_begin()); }
500 
501  const_iterator
502  cend() const noexcept
503  { return const_iterator(nullptr); }
504 
505  size_type
506  size() const noexcept
507  { return _M_element_count; }
508 
509  bool
510  empty() const noexcept
511  { return size() == 0; }
512 
513  allocator_type
514  get_allocator() const noexcept
515  { return allocator_type(this->_M_node_allocator()); }
516 
517  size_type
518  max_size() const noexcept
519  { return __node_alloc_traits::max_size(this->_M_node_allocator()); }
520 
521  // Observers
522  key_equal
523  key_eq() const
524  { return this->_M_eq(); }
525 
526  // hash_function, if present, comes from _Hash_code_base.
527 
528  // Bucket operations
529  size_type
530  bucket_count() const noexcept
531  { return _M_bucket_count; }
532 
533  size_type
534  max_bucket_count() const noexcept
535  { return max_size(); }
536 
537  size_type
538  bucket_size(size_type __n) const
539  { return std::distance(begin(__n), end(__n)); }
540 
541  size_type
542  bucket(const key_type& __k) const
543  { return _M_bucket_index(__k, this->_M_hash_code(__k)); }
544 
545  local_iterator
546  begin(size_type __n)
547  {
548  return local_iterator(*this, _M_bucket_begin(__n),
549  __n, _M_bucket_count);
550  }
551 
552  local_iterator
553  end(size_type __n)
554  { return local_iterator(*this, nullptr, __n, _M_bucket_count); }
555 
556  const_local_iterator
557  begin(size_type __n) const
558  {
559  return const_local_iterator(*this, _M_bucket_begin(__n),
560  __n, _M_bucket_count);
561  }
562 
563  const_local_iterator
564  end(size_type __n) const
565  { return const_local_iterator(*this, nullptr, __n, _M_bucket_count); }
566 
567  // DR 691.
568  const_local_iterator
569  cbegin(size_type __n) const
570  {
571  return const_local_iterator(*this, _M_bucket_begin(__n),
572  __n, _M_bucket_count);
573  }
574 
575  const_local_iterator
576  cend(size_type __n) const
577  { return const_local_iterator(*this, nullptr, __n, _M_bucket_count); }
578 
579  float
580  load_factor() const noexcept
581  {
582  return static_cast<float>(size()) / static_cast<float>(bucket_count());
583  }
584 
585  // max_load_factor, if present, comes from _Rehash_base.
586 
587  // Generalization of max_load_factor. Extension, not found in
588  // TR1. Only useful if _RehashPolicy is something other than
589  // the default.
590  const _RehashPolicy&
591  __rehash_policy() const
592  { return _M_rehash_policy; }
593 
594  void
595  __rehash_policy(const _RehashPolicy&);
596 
597  // Lookup.
598  iterator
599  find(const key_type& __k);
600 
601  const_iterator
602  find(const key_type& __k) const;
603 
604  size_type
605  count(const key_type& __k) const;
606 
608  equal_range(const key_type& __k);
609 
611  equal_range(const key_type& __k) const;
612 
613  protected:
614  // Bucket index computation helpers.
615  size_type
616  _M_bucket_index(__node_type* __n) const noexcept
617  { return __hash_code_base::_M_bucket_index(__n, _M_bucket_count); }
618 
619  size_type
620  _M_bucket_index(const key_type& __k, __hash_code __c) const
621  { return __hash_code_base::_M_bucket_index(__k, __c, _M_bucket_count); }
622 
623  // Find and insert helper functions and types
624  // Find the node before the one matching the criteria.
625  __node_base*
626  _M_find_before_node(size_type, const key_type&, __hash_code) const;
627 
628  __node_type*
629  _M_find_node(size_type __bkt, const key_type& __key,
630  __hash_code __c) const
631  {
632  __node_base* __before_n = _M_find_before_node(__bkt, __key, __c);
633  if (__before_n)
634  return static_cast<__node_type*>(__before_n->_M_nxt);
635  return nullptr;
636  }
637 
638  // Insert a node at the beginning of a bucket.
639  void
640  _M_insert_bucket_begin(size_type, __node_type*);
641 
642  // Remove the bucket first node
643  void
644  _M_remove_bucket_begin(size_type __bkt, __node_type* __next_n,
645  size_type __next_bkt);
646 
647  // Get the node before __n in the bucket __bkt
648  __node_base*
649  _M_get_previous_node(size_type __bkt, __node_base* __n);
650 
651  // Insert node with hash code __code, in bucket bkt if no rehash (assumes
652  // no element with its key already present). Take ownership of the node,
653  // deallocate it on exception.
654  iterator
655  _M_insert_unique_node(size_type __bkt, __hash_code __code,
656  __node_type* __n);
657 
658  // Insert node with hash code __code. Take ownership of the node,
659  // deallocate it on exception.
660  iterator
661  _M_insert_multi_node(__node_type* __hint,
662  __hash_code __code, __node_type* __n);
663 
664  template<typename... _Args>
666  _M_emplace(std::true_type, _Args&&... __args);
667 
668  template<typename... _Args>
669  iterator
670  _M_emplace(std::false_type __uk, _Args&&... __args)
671  { return _M_emplace(cend(), __uk, std::forward<_Args>(__args)...); }
672 
673  // Emplace with hint, useless when keys are unique.
674  template<typename... _Args>
675  iterator
676  _M_emplace(const_iterator, std::true_type __uk, _Args&&... __args)
677  { return _M_emplace(__uk, std::forward<_Args>(__args)...).first; }
678 
679  template<typename... _Args>
680  iterator
681  _M_emplace(const_iterator, std::false_type, _Args&&... __args);
682 
683  template<typename _Arg, typename _NodeGenerator>
685  _M_insert(_Arg&&, const _NodeGenerator&, std::true_type);
686 
687  template<typename _Arg, typename _NodeGenerator>
688  iterator
689  _M_insert(_Arg&& __arg, const _NodeGenerator& __node_gen,
690  std::false_type __uk)
691  {
692  return _M_insert(cend(), std::forward<_Arg>(__arg), __node_gen,
693  __uk);
694  }
695 
696  // Insert with hint, not used when keys are unique.
697  template<typename _Arg, typename _NodeGenerator>
698  iterator
699  _M_insert(const_iterator, _Arg&& __arg,
700  const _NodeGenerator& __node_gen, std::true_type __uk)
701  {
702  return
703  _M_insert(std::forward<_Arg>(__arg), __node_gen, __uk).first;
704  }
705 
706  // Insert with hint when keys are not unique.
707  template<typename _Arg, typename _NodeGenerator>
708  iterator
709  _M_insert(const_iterator, _Arg&&,
710  const _NodeGenerator&, std::false_type);
711 
712  size_type
713  _M_erase(std::true_type, const key_type&);
714 
715  size_type
716  _M_erase(std::false_type, const key_type&);
717 
718  iterator
719  _M_erase(size_type __bkt, __node_base* __prev_n, __node_type* __n);
720 
721  public:
722  // Emplace
723  template<typename... _Args>
724  __ireturn_type
725  emplace(_Args&&... __args)
726  { return _M_emplace(__unique_keys(), std::forward<_Args>(__args)...); }
727 
728  template<typename... _Args>
729  iterator
730  emplace_hint(const_iterator __hint, _Args&&... __args)
731  {
732  return _M_emplace(__hint, __unique_keys(),
733  std::forward<_Args>(__args)...);
734  }
735 
736  // Insert member functions via inheritance.
737 
738  // Erase
739  iterator
740  erase(const_iterator);
741 
742  // LWG 2059.
743  iterator
744  erase(iterator __it)
745  { return erase(const_iterator(__it)); }
746 
747  size_type
748  erase(const key_type& __k)
749  { return _M_erase(__unique_keys(), __k); }
750 
751  iterator
752  erase(const_iterator, const_iterator);
753 
754  void
755  clear() noexcept;
756 
757  // Set number of buckets to be appropriate for container of n element.
758  void rehash(size_type __n);
759 
760  // DR 1189.
761  // reserve, if present, comes from _Rehash_base.
762 
763  private:
764  // Helper rehash method used when keys are unique.
765  void _M_rehash_aux(size_type __n, std::true_type);
766 
767  // Helper rehash method used when keys can be non-unique.
768  void _M_rehash_aux(size_type __n, std::false_type);
769 
770  // Unconditionally change size of bucket array to n, restore
771  // hash policy state to __state on exception.
772  void _M_rehash(size_type __n, const __rehash_state& __state);
773  };
774 
775 
776  // Definitions of class template _Hashtable's out-of-line member functions.
777  template<typename _Key, typename _Value,
778  typename _Alloc, typename _ExtractKey, typename _Equal,
779  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
780  typename _Traits>
781  auto
782  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
783  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
784  _M_bucket_begin(size_type __bkt) const
785  -> __node_type*
786  {
787  __node_base* __n = _M_buckets[__bkt];
788  return __n ? static_cast<__node_type*>(__n->_M_nxt) : nullptr;
789  }
790 
791  template<typename _Key, typename _Value,
792  typename _Alloc, typename _ExtractKey, typename _Equal,
793  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
794  typename _Traits>
795  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
796  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
797  _Hashtable(size_type __bucket_hint,
798  const _H1& __h1, const _H2& __h2, const _Hash& __h,
799  const _Equal& __eq, const _ExtractKey& __exk,
800  const allocator_type& __a)
801  : _Hashtable(__h1, __h2, __h, __eq, __exk, __a)
802  {
803  auto __bkt = _M_rehash_policy._M_next_bkt(__bucket_hint);
804  if (__bkt > _M_bucket_count)
805  {
806  _M_buckets = _M_allocate_buckets(__bkt);
807  _M_bucket_count = __bkt;
808  }
809  }
810 
811  template<typename _Key, typename _Value,
812  typename _Alloc, typename _ExtractKey, typename _Equal,
813  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
814  typename _Traits>
815  template<typename _InputIterator>
816  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
817  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
818  _Hashtable(_InputIterator __f, _InputIterator __l,
819  size_type __bucket_hint,
820  const _H1& __h1, const _H2& __h2, const _Hash& __h,
821  const _Equal& __eq, const _ExtractKey& __exk,
822  const allocator_type& __a)
823  : _Hashtable(__h1, __h2, __h, __eq, __exk, __a)
824  {
825  auto __nb_elems = __detail::__distance_fw(__f, __l);
826  auto __bkt_count =
827  _M_rehash_policy._M_next_bkt(
828  std::max(_M_rehash_policy._M_bkt_for_elements(__nb_elems),
829  __bucket_hint));
830 
831  if (__bkt_count > _M_bucket_count)
832  {
833  _M_buckets = _M_allocate_buckets(__bkt_count);
834  _M_bucket_count = __bkt_count;
835  }
836 
837  for (; __f != __l; ++__f)
838  this->insert(*__f);
839  }
840 
841  template<typename _Key, typename _Value,
842  typename _Alloc, typename _ExtractKey, typename _Equal,
843  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
844  typename _Traits>
845  auto
846  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
847  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
848  operator=(const _Hashtable& __ht)
849  -> _Hashtable&
850  {
851  if (&__ht == this)
852  return *this;
853 
854  if (__node_alloc_traits::_S_propagate_on_copy_assign())
855  {
856  auto& __this_alloc = this->_M_node_allocator();
857  auto& __that_alloc = __ht._M_node_allocator();
858  if (!__node_alloc_traits::_S_always_equal()
859  && __this_alloc != __that_alloc)
860  {
861  // Replacement allocator cannot free existing storage.
862  this->_M_deallocate_nodes(_M_begin());
863  _M_before_begin._M_nxt = nullptr;
864  _M_deallocate_buckets();
865  _M_buckets = nullptr;
866  std::__alloc_on_copy(__this_alloc, __that_alloc);
867  __hashtable_base::operator=(__ht);
868  _M_bucket_count = __ht._M_bucket_count;
869  _M_element_count = __ht._M_element_count;
870  _M_rehash_policy = __ht._M_rehash_policy;
871  __try
872  {
873  _M_assign(__ht,
874  [this](const __node_type* __n)
875  { return this->_M_allocate_node(__n->_M_v()); });
876  }
877  __catch(...)
878  {
879  // _M_assign took care of deallocating all memory. Now we
880  // must make sure this instance remains in a usable state.
881  _M_reset();
882  __throw_exception_again;
883  }
884  return *this;
885  }
886  std::__alloc_on_copy(__this_alloc, __that_alloc);
887  }
888 
889  // Reuse allocated buckets and nodes.
890  __bucket_type* __former_buckets = nullptr;
891  std::size_t __former_bucket_count = _M_bucket_count;
892  const __rehash_state& __former_state = _M_rehash_policy._M_state();
893 
894  if (_M_bucket_count != __ht._M_bucket_count)
895  {
896  __former_buckets = _M_buckets;
897  _M_buckets = _M_allocate_buckets(__ht._M_bucket_count);
898  _M_bucket_count = __ht._M_bucket_count;
899  }
900  else
901  __builtin_memset(_M_buckets, 0,
902  _M_bucket_count * sizeof(__bucket_type));
903 
904  __try
905  {
906  __hashtable_base::operator=(__ht);
907  _M_element_count = __ht._M_element_count;
908  _M_rehash_policy = __ht._M_rehash_policy;
909  __reuse_or_alloc_node_type __roan(_M_begin(), *this);
910  _M_before_begin._M_nxt = nullptr;
911  _M_assign(__ht,
912  [&__roan](const __node_type* __n)
913  { return __roan(__n->_M_v()); });
914  if (__former_buckets)
915  _M_deallocate_buckets(__former_buckets, __former_bucket_count);
916  }
917  __catch(...)
918  {
919  if (__former_buckets)
920  {
921  // Restore previous buckets.
922  _M_deallocate_buckets();
923  _M_rehash_policy._M_reset(__former_state);
924  _M_buckets = __former_buckets;
925  _M_bucket_count = __former_bucket_count;
926  }
927  __builtin_memset(_M_buckets, 0,
928  _M_bucket_count * sizeof(__bucket_type));
929  __throw_exception_again;
930  }
931  return *this;
932  }
933 
934  template<typename _Key, typename _Value,
935  typename _Alloc, typename _ExtractKey, typename _Equal,
936  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
937  typename _Traits>
938  template<typename _NodeGenerator>
939  void
940  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
941  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
942  _M_assign(const _Hashtable& __ht, const _NodeGenerator& __node_gen)
943  {
944  __bucket_type* __buckets = nullptr;
945  if (!_M_buckets)
946  _M_buckets = __buckets = _M_allocate_buckets(_M_bucket_count);
947 
948  __try
949  {
950  if (!__ht._M_before_begin._M_nxt)
951  return;
952 
953  // First deal with the special first node pointed to by
954  // _M_before_begin.
955  __node_type* __ht_n = __ht._M_begin();
956  __node_type* __this_n = __node_gen(__ht_n);
957  this->_M_copy_code(__this_n, __ht_n);
958  _M_before_begin._M_nxt = __this_n;
959  _M_buckets[_M_bucket_index(__this_n)] = &_M_before_begin;
960 
961  // Then deal with other nodes.
962  __node_base* __prev_n = __this_n;
963  for (__ht_n = __ht_n->_M_next(); __ht_n; __ht_n = __ht_n->_M_next())
964  {
965  __this_n = __node_gen(__ht_n);
966  __prev_n->_M_nxt = __this_n;
967  this->_M_copy_code(__this_n, __ht_n);
968  size_type __bkt = _M_bucket_index(__this_n);
969  if (!_M_buckets[__bkt])
970  _M_buckets[__bkt] = __prev_n;
971  __prev_n = __this_n;
972  }
973  }
974  __catch(...)
975  {
976  clear();
977  if (__buckets)
978  _M_deallocate_buckets();
979  __throw_exception_again;
980  }
981  }
982 
983  template<typename _Key, typename _Value,
984  typename _Alloc, typename _ExtractKey, typename _Equal,
985  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
986  typename _Traits>
987  void
988  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
989  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
990  _M_reset() noexcept
991  {
992  _M_rehash_policy._M_reset();
993  _M_bucket_count = 1;
994  _M_single_bucket = nullptr;
995  _M_buckets = &_M_single_bucket;
996  _M_before_begin._M_nxt = nullptr;
997  _M_element_count = 0;
998  }
999 
1000  template<typename _Key, typename _Value,
1001  typename _Alloc, typename _ExtractKey, typename _Equal,
1002  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1003  typename _Traits>
1004  void
1005  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1006  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1007  _M_move_assign(_Hashtable&& __ht, std::true_type)
1008  {
1009  this->_M_deallocate_nodes(_M_begin());
1010  _M_deallocate_buckets();
1011  __hashtable_base::operator=(std::move(__ht));
1012  _M_rehash_policy = __ht._M_rehash_policy;
1013  if (!__ht._M_uses_single_bucket())
1014  _M_buckets = __ht._M_buckets;
1015  else
1016  {
1017  _M_buckets = &_M_single_bucket;
1018  _M_single_bucket = __ht._M_single_bucket;
1019  }
1020  _M_bucket_count = __ht._M_bucket_count;
1021  _M_before_begin._M_nxt = __ht._M_before_begin._M_nxt;
1022  _M_element_count = __ht._M_element_count;
1023  std::__alloc_on_move(this->_M_node_allocator(), __ht._M_node_allocator());
1024 
1025  // Fix buckets containing the _M_before_begin pointers that can't be
1026  // moved.
1027  if (_M_begin())
1028  _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
1029  __ht._M_reset();
1030  }
1031 
1032  template<typename _Key, typename _Value,
1033  typename _Alloc, typename _ExtractKey, typename _Equal,
1034  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1035  typename _Traits>
1036  void
1037  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1038  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1039  _M_move_assign(_Hashtable&& __ht, std::false_type)
1040  {
1041  if (__ht._M_node_allocator() == this->_M_node_allocator())
1042  _M_move_assign(std::move(__ht), std::true_type());
1043  else
1044  {
1045  // Can't move memory, move elements then.
1046  __bucket_type* __former_buckets = nullptr;
1047  size_type __former_bucket_count = _M_bucket_count;
1048  const __rehash_state& __former_state = _M_rehash_policy._M_state();
1049 
1050  if (_M_bucket_count != __ht._M_bucket_count)
1051  {
1052  __former_buckets = _M_buckets;
1053  _M_buckets = _M_allocate_buckets(__ht._M_bucket_count);
1054  _M_bucket_count = __ht._M_bucket_count;
1055  }
1056  else
1057  __builtin_memset(_M_buckets, 0,
1058  _M_bucket_count * sizeof(__bucket_type));
1059 
1060  __try
1061  {
1062  __hashtable_base::operator=(std::move(__ht));
1063  _M_element_count = __ht._M_element_count;
1064  _M_rehash_policy = __ht._M_rehash_policy;
1065  __reuse_or_alloc_node_type __roan(_M_begin(), *this);
1066  _M_before_begin._M_nxt = nullptr;
1067  _M_assign(__ht,
1068  [&__roan](__node_type* __n)
1069  { return __roan(std::move_if_noexcept(__n->_M_v())); });
1070  __ht.clear();
1071  }
1072  __catch(...)
1073  {
1074  if (__former_buckets)
1075  {
1076  _M_deallocate_buckets();
1077  _M_rehash_policy._M_reset(__former_state);
1078  _M_buckets = __former_buckets;
1079  _M_bucket_count = __former_bucket_count;
1080  }
1081  __builtin_memset(_M_buckets, 0,
1082  _M_bucket_count * sizeof(__bucket_type));
1083  __throw_exception_again;
1084  }
1085  }
1086  }
1087 
1088  template<typename _Key, typename _Value,
1089  typename _Alloc, typename _ExtractKey, typename _Equal,
1090  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1091  typename _Traits>
1092  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1093  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1094  _Hashtable(const _Hashtable& __ht)
1095  : __hashtable_base(__ht),
1096  __map_base(__ht),
1097  __rehash_base(__ht),
1099  __node_alloc_traits::_S_select_on_copy(__ht._M_node_allocator())),
1100  _M_buckets(nullptr),
1101  _M_bucket_count(__ht._M_bucket_count),
1102  _M_element_count(__ht._M_element_count),
1103  _M_rehash_policy(__ht._M_rehash_policy)
1104  {
1105  _M_assign(__ht,
1106  [this](const __node_type* __n)
1107  { return this->_M_allocate_node(__n->_M_v()); });
1108  }
1109 
1110  template<typename _Key, typename _Value,
1111  typename _Alloc, typename _ExtractKey, typename _Equal,
1112  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1113  typename _Traits>
1114  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1115  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1116  _Hashtable(_Hashtable&& __ht) noexcept
1117  : __hashtable_base(__ht),
1118  __map_base(__ht),
1119  __rehash_base(__ht),
1120  __hashtable_alloc(std::move(__ht._M_base_alloc())),
1121  _M_buckets(__ht._M_buckets),
1122  _M_bucket_count(__ht._M_bucket_count),
1123  _M_before_begin(__ht._M_before_begin._M_nxt),
1124  _M_element_count(__ht._M_element_count),
1125  _M_rehash_policy(__ht._M_rehash_policy)
1126  {
1127  // Update, if necessary, buckets if __ht is using its single bucket.
1128  if (__ht._M_uses_single_bucket())
1129  {
1130  _M_buckets = &_M_single_bucket;
1131  _M_single_bucket = __ht._M_single_bucket;
1132  }
1133 
1134  // Update, if necessary, bucket pointing to before begin that hasn't
1135  // moved.
1136  if (_M_begin())
1137  _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
1138 
1139  __ht._M_reset();
1140  }
1141 
1142  template<typename _Key, typename _Value,
1143  typename _Alloc, typename _ExtractKey, typename _Equal,
1144  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1145  typename _Traits>
1146  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1147  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1148  _Hashtable(const _Hashtable& __ht, const allocator_type& __a)
1149  : __hashtable_base(__ht),
1150  __map_base(__ht),
1151  __rehash_base(__ht),
1152  __hashtable_alloc(__node_alloc_type(__a)),
1153  _M_buckets(),
1154  _M_bucket_count(__ht._M_bucket_count),
1155  _M_element_count(__ht._M_element_count),
1156  _M_rehash_policy(__ht._M_rehash_policy)
1157  {
1158  _M_assign(__ht,
1159  [this](const __node_type* __n)
1160  { return this->_M_allocate_node(__n->_M_v()); });
1161  }
1162 
1163  template<typename _Key, typename _Value,
1164  typename _Alloc, typename _ExtractKey, typename _Equal,
1165  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1166  typename _Traits>
1167  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1168  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1169  _Hashtable(_Hashtable&& __ht, const allocator_type& __a)
1170  : __hashtable_base(__ht),
1171  __map_base(__ht),
1172  __rehash_base(__ht),
1173  __hashtable_alloc(__node_alloc_type(__a)),
1174  _M_buckets(nullptr),
1175  _M_bucket_count(__ht._M_bucket_count),
1176  _M_element_count(__ht._M_element_count),
1177  _M_rehash_policy(__ht._M_rehash_policy)
1178  {
1179  if (__ht._M_node_allocator() == this->_M_node_allocator())
1180  {
1181  if (__ht._M_uses_single_bucket())
1182  {
1183  _M_buckets = &_M_single_bucket;
1184  _M_single_bucket = __ht._M_single_bucket;
1185  }
1186  else
1187  _M_buckets = __ht._M_buckets;
1188 
1189  _M_before_begin._M_nxt = __ht._M_before_begin._M_nxt;
1190  // Update, if necessary, bucket pointing to before begin that hasn't
1191  // moved.
1192  if (_M_begin())
1193  _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
1194  __ht._M_reset();
1195  }
1196  else
1197  {
1198  _M_assign(__ht,
1199  [this](__node_type* __n)
1200  {
1201  return this->_M_allocate_node(
1202  std::move_if_noexcept(__n->_M_v()));
1203  });
1204  __ht.clear();
1205  }
1206  }
1207 
1208  template<typename _Key, typename _Value,
1209  typename _Alloc, typename _ExtractKey, typename _Equal,
1210  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1211  typename _Traits>
1212  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1213  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1214  ~_Hashtable() noexcept
1215  {
1216  clear();
1217  _M_deallocate_buckets();
1218  }
1219 
1220  template<typename _Key, typename _Value,
1221  typename _Alloc, typename _ExtractKey, typename _Equal,
1222  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1223  typename _Traits>
1224  void
1225  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1226  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1227  swap(_Hashtable& __x)
1228  noexcept(__node_alloc_traits::_S_nothrow_swap())
1229  {
1230  // The only base class with member variables is hash_code_base.
1231  // We define _Hash_code_base::_M_swap because different
1232  // specializations have different members.
1233  this->_M_swap(__x);
1234 
1235  std::__alloc_on_swap(this->_M_node_allocator(), __x._M_node_allocator());
1236  std::swap(_M_rehash_policy, __x._M_rehash_policy);
1237 
1238  // Deal properly with potentially moved instances.
1239  if (this->_M_uses_single_bucket())
1240  {
1241  if (!__x._M_uses_single_bucket())
1242  {
1243  _M_buckets = __x._M_buckets;
1244  __x._M_buckets = &__x._M_single_bucket;
1245  }
1246  }
1247  else if (__x._M_uses_single_bucket())
1248  {
1249  __x._M_buckets = _M_buckets;
1250  _M_buckets = &_M_single_bucket;
1251  }
1252  else
1253  std::swap(_M_buckets, __x._M_buckets);
1254 
1255  std::swap(_M_bucket_count, __x._M_bucket_count);
1256  std::swap(_M_before_begin._M_nxt, __x._M_before_begin._M_nxt);
1257  std::swap(_M_element_count, __x._M_element_count);
1258  std::swap(_M_single_bucket, __x._M_single_bucket);
1259 
1260  // Fix buckets containing the _M_before_begin pointers that can't be
1261  // swapped.
1262  if (_M_begin())
1263  _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
1264 
1265  if (__x._M_begin())
1266  __x._M_buckets[__x._M_bucket_index(__x._M_begin())]
1267  = &__x._M_before_begin;
1268  }
1269 
1270  template<typename _Key, typename _Value,
1271  typename _Alloc, typename _ExtractKey, typename _Equal,
1272  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1273  typename _Traits>
1274  void
1275  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1276  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1277  __rehash_policy(const _RehashPolicy& __pol)
1278  {
1279  auto __do_rehash =
1280  __pol._M_need_rehash(_M_bucket_count, _M_element_count, 0);
1281  if (__do_rehash.first)
1282  _M_rehash(__do_rehash.second, _M_rehash_policy._M_state());
1283  _M_rehash_policy = __pol;
1284  }
1285 
1286  template<typename _Key, typename _Value,
1287  typename _Alloc, typename _ExtractKey, typename _Equal,
1288  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1289  typename _Traits>
1290  auto
1291  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1292  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1293  find(const key_type& __k)
1294  -> iterator
1295  {
1296  __hash_code __code = this->_M_hash_code(__k);
1297  std::size_t __n = _M_bucket_index(__k, __code);
1298  __node_type* __p = _M_find_node(__n, __k, __code);
1299  return __p ? iterator(__p) : end();
1300  }
1301 
1302  template<typename _Key, typename _Value,
1303  typename _Alloc, typename _ExtractKey, typename _Equal,
1304  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1305  typename _Traits>
1306  auto
1307  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1308  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1309  find(const key_type& __k) const
1310  -> const_iterator
1311  {
1312  __hash_code __code = this->_M_hash_code(__k);
1313  std::size_t __n = _M_bucket_index(__k, __code);
1314  __node_type* __p = _M_find_node(__n, __k, __code);
1315  return __p ? const_iterator(__p) : end();
1316  }
1317 
1318  template<typename _Key, typename _Value,
1319  typename _Alloc, typename _ExtractKey, typename _Equal,
1320  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1321  typename _Traits>
1322  auto
1323  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1324  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1325  count(const key_type& __k) const
1326  -> size_type
1327  {
1328  __hash_code __code = this->_M_hash_code(__k);
1329  std::size_t __n = _M_bucket_index(__k, __code);
1330  __node_type* __p = _M_bucket_begin(__n);
1331  if (!__p)
1332  return 0;
1333 
1334  std::size_t __result = 0;
1335  for (;; __p = __p->_M_next())
1336  {
1337  if (this->_M_equals(__k, __code, __p))
1338  ++__result;
1339  else if (__result)
1340  // All equivalent values are next to each other, if we
1341  // found a non-equivalent value after an equivalent one it
1342  // means that we won't find any new equivalent value.
1343  break;
1344  if (!__p->_M_nxt || _M_bucket_index(__p->_M_next()) != __n)
1345  break;
1346  }
1347  return __result;
1348  }
1349 
1350  template<typename _Key, typename _Value,
1351  typename _Alloc, typename _ExtractKey, typename _Equal,
1352  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1353  typename _Traits>
1354  auto
1355  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1356  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1357  equal_range(const key_type& __k)
1359  {
1360  __hash_code __code = this->_M_hash_code(__k);
1361  std::size_t __n = _M_bucket_index(__k, __code);
1362  __node_type* __p = _M_find_node(__n, __k, __code);
1363 
1364  if (__p)
1365  {
1366  __node_type* __p1 = __p->_M_next();
1367  while (__p1 && _M_bucket_index(__p1) == __n
1368  && this->_M_equals(__k, __code, __p1))
1369  __p1 = __p1->_M_next();
1370 
1371  return std::make_pair(iterator(__p), iterator(__p1));
1372  }
1373  else
1374  return std::make_pair(end(), end());
1375  }
1376 
1377  template<typename _Key, typename _Value,
1378  typename _Alloc, typename _ExtractKey, typename _Equal,
1379  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1380  typename _Traits>
1381  auto
1382  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1383  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1384  equal_range(const key_type& __k) const
1386  {
1387  __hash_code __code = this->_M_hash_code(__k);
1388  std::size_t __n = _M_bucket_index(__k, __code);
1389  __node_type* __p = _M_find_node(__n, __k, __code);
1390 
1391  if (__p)
1392  {
1393  __node_type* __p1 = __p->_M_next();
1394  while (__p1 && _M_bucket_index(__p1) == __n
1395  && this->_M_equals(__k, __code, __p1))
1396  __p1 = __p1->_M_next();
1397 
1398  return std::make_pair(const_iterator(__p), const_iterator(__p1));
1399  }
1400  else
1401  return std::make_pair(end(), end());
1402  }
1403 
1404  // Find the node whose key compares equal to k in the bucket n.
1405  // Return nullptr if no node is found.
1406  template<typename _Key, typename _Value,
1407  typename _Alloc, typename _ExtractKey, typename _Equal,
1408  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1409  typename _Traits>
1410  auto
1411  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1412  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1413  _M_find_before_node(size_type __n, const key_type& __k,
1414  __hash_code __code) const
1415  -> __node_base*
1416  {
1417  __node_base* __prev_p = _M_buckets[__n];
1418  if (!__prev_p)
1419  return nullptr;
1420 
1421  for (__node_type* __p = static_cast<__node_type*>(__prev_p->_M_nxt);;
1422  __p = __p->_M_next())
1423  {
1424  if (this->_M_equals(__k, __code, __p))
1425  return __prev_p;
1426 
1427  if (!__p->_M_nxt || _M_bucket_index(__p->_M_next()) != __n)
1428  break;
1429  __prev_p = __p;
1430  }
1431  return nullptr;
1432  }
1433 
1434  template<typename _Key, typename _Value,
1435  typename _Alloc, typename _ExtractKey, typename _Equal,
1436  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1437  typename _Traits>
1438  void
1439  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1440  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1441  _M_insert_bucket_begin(size_type __bkt, __node_type* __node)
1442  {
1443  if (_M_buckets[__bkt])
1444  {
1445  // Bucket is not empty, we just need to insert the new node
1446  // after the bucket before begin.
1447  __node->_M_nxt = _M_buckets[__bkt]->_M_nxt;
1448  _M_buckets[__bkt]->_M_nxt = __node;
1449  }
1450  else
1451  {
1452  // The bucket is empty, the new node is inserted at the
1453  // beginning of the singly-linked list and the bucket will
1454  // contain _M_before_begin pointer.
1455  __node->_M_nxt = _M_before_begin._M_nxt;
1456  _M_before_begin._M_nxt = __node;
1457  if (__node->_M_nxt)
1458  // We must update former begin bucket that is pointing to
1459  // _M_before_begin.
1460  _M_buckets[_M_bucket_index(__node->_M_next())] = __node;
1461  _M_buckets[__bkt] = &_M_before_begin;
1462  }
1463  }
1464 
1465  template<typename _Key, typename _Value,
1466  typename _Alloc, typename _ExtractKey, typename _Equal,
1467  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1468  typename _Traits>
1469  void
1470  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1471  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1472  _M_remove_bucket_begin(size_type __bkt, __node_type* __next,
1473  size_type __next_bkt)
1474  {
1475  if (!__next || __next_bkt != __bkt)
1476  {
1477  // Bucket is now empty
1478  // First update next bucket if any
1479  if (__next)
1480  _M_buckets[__next_bkt] = _M_buckets[__bkt];
1481 
1482  // Second update before begin node if necessary
1483  if (&_M_before_begin == _M_buckets[__bkt])
1484  _M_before_begin._M_nxt = __next;
1485  _M_buckets[__bkt] = nullptr;
1486  }
1487  }
1488 
1489  template<typename _Key, typename _Value,
1490  typename _Alloc, typename _ExtractKey, typename _Equal,
1491  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1492  typename _Traits>
1493  auto
1494  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1495  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1496  _M_get_previous_node(size_type __bkt, __node_base* __n)
1497  -> __node_base*
1498  {
1499  __node_base* __prev_n = _M_buckets[__bkt];
1500  while (__prev_n->_M_nxt != __n)
1501  __prev_n = __prev_n->_M_nxt;
1502  return __prev_n;
1503  }
1504 
1505  template<typename _Key, typename _Value,
1506  typename _Alloc, typename _ExtractKey, typename _Equal,
1507  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1508  typename _Traits>
1509  template<typename... _Args>
1510  auto
1511  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1512  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1513  _M_emplace(std::true_type, _Args&&... __args)
1515  {
1516  // First build the node to get access to the hash code
1517  __node_type* __node = this->_M_allocate_node(std::forward<_Args>(__args)...);
1518  const key_type& __k = this->_M_extract()(__node->_M_v());
1519  __hash_code __code;
1520  __try
1521  {
1522  __code = this->_M_hash_code(__k);
1523  }
1524  __catch(...)
1525  {
1526  this->_M_deallocate_node(__node);
1527  __throw_exception_again;
1528  }
1529 
1530  size_type __bkt = _M_bucket_index(__k, __code);
1531  if (__node_type* __p = _M_find_node(__bkt, __k, __code))
1532  {
1533  // There is already an equivalent node, no insertion
1534  this->_M_deallocate_node(__node);
1535  return std::make_pair(iterator(__p), false);
1536  }
1537 
1538  // Insert the node
1539  return std::make_pair(_M_insert_unique_node(__bkt, __code, __node),
1540  true);
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  template<typename... _Args>
1548  auto
1549  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1550  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1551  _M_emplace(const_iterator __hint, std::false_type, _Args&&... __args)
1552  -> iterator
1553  {
1554  // First build the node to get its hash code.
1555  __node_type* __node =
1556  this->_M_allocate_node(std::forward<_Args>(__args)...);
1557 
1558  __hash_code __code;
1559  __try
1560  {
1561  __code = this->_M_hash_code(this->_M_extract()(__node->_M_v()));
1562  }
1563  __catch(...)
1564  {
1565  this->_M_deallocate_node(__node);
1566  __throw_exception_again;
1567  }
1568 
1569  return _M_insert_multi_node(__hint._M_cur, __code, __node);
1570  }
1571 
1572  template<typename _Key, typename _Value,
1573  typename _Alloc, typename _ExtractKey, typename _Equal,
1574  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1575  typename _Traits>
1576  auto
1577  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1578  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1579  _M_insert_unique_node(size_type __bkt, __hash_code __code,
1580  __node_type* __node)
1581  -> iterator
1582  {
1583  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
1584  std::pair<bool, std::size_t> __do_rehash
1585  = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count, 1);
1586 
1587  __try
1588  {
1589  if (__do_rehash.first)
1590  {
1591  _M_rehash(__do_rehash.second, __saved_state);
1592  __bkt = _M_bucket_index(this->_M_extract()(__node->_M_v()), __code);
1593  }
1594 
1595  this->_M_store_code(__node, __code);
1596 
1597  // Always insert at the beginning of the bucket.
1598  _M_insert_bucket_begin(__bkt, __node);
1599  ++_M_element_count;
1600  return iterator(__node);
1601  }
1602  __catch(...)
1603  {
1604  this->_M_deallocate_node(__node);
1605  __throw_exception_again;
1606  }
1607  }
1608 
1609  // Insert node, in bucket bkt if no rehash (assumes no element with its key
1610  // already present). Take ownership of the node, deallocate it on exception.
1611  template<typename _Key, typename _Value,
1612  typename _Alloc, typename _ExtractKey, typename _Equal,
1613  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1614  typename _Traits>
1615  auto
1616  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1617  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1618  _M_insert_multi_node(__node_type* __hint, __hash_code __code,
1619  __node_type* __node)
1620  -> iterator
1621  {
1622  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
1623  std::pair<bool, std::size_t> __do_rehash
1624  = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count, 1);
1625 
1626  __try
1627  {
1628  if (__do_rehash.first)
1629  _M_rehash(__do_rehash.second, __saved_state);
1630 
1631  this->_M_store_code(__node, __code);
1632  const key_type& __k = this->_M_extract()(__node->_M_v());
1633  size_type __bkt = _M_bucket_index(__k, __code);
1634 
1635  // Find the node before an equivalent one or use hint if it exists and
1636  // if it is equivalent.
1637  __node_base* __prev
1638  = __builtin_expect(__hint != nullptr, false)
1639  && this->_M_equals(__k, __code, __hint)
1640  ? __hint
1641  : _M_find_before_node(__bkt, __k, __code);
1642  if (__prev)
1643  {
1644  // Insert after the node before the equivalent one.
1645  __node->_M_nxt = __prev->_M_nxt;
1646  __prev->_M_nxt = __node;
1647  if (__builtin_expect(__prev == __hint, false))
1648  // hint might be the last bucket node, in this case we need to
1649  // update next bucket.
1650  if (__node->_M_nxt
1651  && !this->_M_equals(__k, __code, __node->_M_next()))
1652  {
1653  size_type __next_bkt = _M_bucket_index(__node->_M_next());
1654  if (__next_bkt != __bkt)
1655  _M_buckets[__next_bkt] = __node;
1656  }
1657  }
1658  else
1659  // The inserted node has no equivalent in the
1660  // hashtable. We must insert the new node at the
1661  // beginning of the bucket to preserve equivalent
1662  // elements' relative positions.
1663  _M_insert_bucket_begin(__bkt, __node);
1664  ++_M_element_count;
1665  return iterator(__node);
1666  }
1667  __catch(...)
1668  {
1669  this->_M_deallocate_node(__node);
1670  __throw_exception_again;
1671  }
1672  }
1673 
1674  // Insert v if no element with its key is already present.
1675  template<typename _Key, typename _Value,
1676  typename _Alloc, typename _ExtractKey, typename _Equal,
1677  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1678  typename _Traits>
1679  template<typename _Arg, typename _NodeGenerator>
1680  auto
1681  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1682  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1683  _M_insert(_Arg&& __v, const _NodeGenerator& __node_gen, std::true_type)
1685  {
1686  const key_type& __k = this->_M_extract()(__v);
1687  __hash_code __code = this->_M_hash_code(__k);
1688  size_type __bkt = _M_bucket_index(__k, __code);
1689 
1690  __node_type* __n = _M_find_node(__bkt, __k, __code);
1691  if (__n)
1692  return std::make_pair(iterator(__n), false);
1693 
1694  __n = __node_gen(std::forward<_Arg>(__v));
1695  return std::make_pair(_M_insert_unique_node(__bkt, __code, __n), true);
1696  }
1697 
1698  // Insert v unconditionally.
1699  template<typename _Key, typename _Value,
1700  typename _Alloc, typename _ExtractKey, typename _Equal,
1701  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1702  typename _Traits>
1703  template<typename _Arg, typename _NodeGenerator>
1704  auto
1705  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1706  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1707  _M_insert(const_iterator __hint, _Arg&& __v,
1708  const _NodeGenerator& __node_gen, std::false_type)
1709  -> iterator
1710  {
1711  // First compute the hash code so that we don't do anything if it
1712  // throws.
1713  __hash_code __code = this->_M_hash_code(this->_M_extract()(__v));
1714 
1715  // Second allocate new node so that we don't rehash if it throws.
1716  __node_type* __node = __node_gen(std::forward<_Arg>(__v));
1717 
1718  return _M_insert_multi_node(__hint._M_cur, __code, __node);
1719  }
1720 
1721  template<typename _Key, typename _Value,
1722  typename _Alloc, typename _ExtractKey, typename _Equal,
1723  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1724  typename _Traits>
1725  auto
1726  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1727  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1728  erase(const_iterator __it)
1729  -> iterator
1730  {
1731  __node_type* __n = __it._M_cur;
1732  std::size_t __bkt = _M_bucket_index(__n);
1733 
1734  // Look for previous node to unlink it from the erased one, this
1735  // is why we need buckets to contain the before begin to make
1736  // this search fast.
1737  __node_base* __prev_n = _M_get_previous_node(__bkt, __n);
1738  return _M_erase(__bkt, __prev_n, __n);
1739  }
1740 
1741  template<typename _Key, typename _Value,
1742  typename _Alloc, typename _ExtractKey, typename _Equal,
1743  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1744  typename _Traits>
1745  auto
1746  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1747  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1748  _M_erase(size_type __bkt, __node_base* __prev_n, __node_type* __n)
1749  -> iterator
1750  {
1751  if (__prev_n == _M_buckets[__bkt])
1752  _M_remove_bucket_begin(__bkt, __n->_M_next(),
1753  __n->_M_nxt ? _M_bucket_index(__n->_M_next()) : 0);
1754  else if (__n->_M_nxt)
1755  {
1756  size_type __next_bkt = _M_bucket_index(__n->_M_next());
1757  if (__next_bkt != __bkt)
1758  _M_buckets[__next_bkt] = __prev_n;
1759  }
1760 
1761  __prev_n->_M_nxt = __n->_M_nxt;
1762  iterator __result(__n->_M_next());
1763  this->_M_deallocate_node(__n);
1764  --_M_element_count;
1765 
1766  return __result;
1767  }
1768 
1769  template<typename _Key, typename _Value,
1770  typename _Alloc, typename _ExtractKey, typename _Equal,
1771  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1772  typename _Traits>
1773  auto
1774  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1775  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1776  _M_erase(std::true_type, const key_type& __k)
1777  -> size_type
1778  {
1779  __hash_code __code = this->_M_hash_code(__k);
1780  std::size_t __bkt = _M_bucket_index(__k, __code);
1781 
1782  // Look for the node before the first matching node.
1783  __node_base* __prev_n = _M_find_before_node(__bkt, __k, __code);
1784  if (!__prev_n)
1785  return 0;
1786 
1787  // We found a matching node, erase it.
1788  __node_type* __n = static_cast<__node_type*>(__prev_n->_M_nxt);
1789  _M_erase(__bkt, __prev_n, __n);
1790  return 1;
1791  }
1792 
1793  template<typename _Key, typename _Value,
1794  typename _Alloc, typename _ExtractKey, typename _Equal,
1795  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1796  typename _Traits>
1797  auto
1798  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1799  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1800  _M_erase(std::false_type, const key_type& __k)
1801  -> size_type
1802  {
1803  __hash_code __code = this->_M_hash_code(__k);
1804  std::size_t __bkt = _M_bucket_index(__k, __code);
1805 
1806  // Look for the node before the first matching node.
1807  __node_base* __prev_n = _M_find_before_node(__bkt, __k, __code);
1808  if (!__prev_n)
1809  return 0;
1810 
1811  // _GLIBCXX_RESOLVE_LIB_DEFECTS
1812  // 526. Is it undefined if a function in the standard changes
1813  // in parameters?
1814  // We use one loop to find all matching nodes and another to deallocate
1815  // them so that the key stays valid during the first loop. It might be
1816  // invalidated indirectly when destroying nodes.
1817  __node_type* __n = static_cast<__node_type*>(__prev_n->_M_nxt);
1818  __node_type* __n_last = __n;
1819  std::size_t __n_last_bkt = __bkt;
1820  do
1821  {
1822  __n_last = __n_last->_M_next();
1823  if (!__n_last)
1824  break;
1825  __n_last_bkt = _M_bucket_index(__n_last);
1826  }
1827  while (__n_last_bkt == __bkt && this->_M_equals(__k, __code, __n_last));
1828 
1829  // Deallocate nodes.
1830  size_type __result = 0;
1831  do
1832  {
1833  __node_type* __p = __n->_M_next();
1834  this->_M_deallocate_node(__n);
1835  __n = __p;
1836  ++__result;
1837  --_M_element_count;
1838  }
1839  while (__n != __n_last);
1840 
1841  if (__prev_n == _M_buckets[__bkt])
1842  _M_remove_bucket_begin(__bkt, __n_last, __n_last_bkt);
1843  else if (__n_last && __n_last_bkt != __bkt)
1844  _M_buckets[__n_last_bkt] = __prev_n;
1845  __prev_n->_M_nxt = __n_last;
1846  return __result;
1847  }
1848 
1849  template<typename _Key, typename _Value,
1850  typename _Alloc, typename _ExtractKey, typename _Equal,
1851  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1852  typename _Traits>
1853  auto
1854  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1855  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1856  erase(const_iterator __first, const_iterator __last)
1857  -> iterator
1858  {
1859  __node_type* __n = __first._M_cur;
1860  __node_type* __last_n = __last._M_cur;
1861  if (__n == __last_n)
1862  return iterator(__n);
1863 
1864  std::size_t __bkt = _M_bucket_index(__n);
1865 
1866  __node_base* __prev_n = _M_get_previous_node(__bkt, __n);
1867  bool __is_bucket_begin = __n == _M_bucket_begin(__bkt);
1868  std::size_t __n_bkt = __bkt;
1869  for (;;)
1870  {
1871  do
1872  {
1873  __node_type* __tmp = __n;
1874  __n = __n->_M_next();
1875  this->_M_deallocate_node(__tmp);
1876  --_M_element_count;
1877  if (!__n)
1878  break;
1879  __n_bkt = _M_bucket_index(__n);
1880  }
1881  while (__n != __last_n && __n_bkt == __bkt);
1882  if (__is_bucket_begin)
1883  _M_remove_bucket_begin(__bkt, __n, __n_bkt);
1884  if (__n == __last_n)
1885  break;
1886  __is_bucket_begin = true;
1887  __bkt = __n_bkt;
1888  }
1889 
1890  if (__n && (__n_bkt != __bkt || __is_bucket_begin))
1891  _M_buckets[__n_bkt] = __prev_n;
1892  __prev_n->_M_nxt = __n;
1893  return iterator(__n);
1894  }
1895 
1896  template<typename _Key, typename _Value,
1897  typename _Alloc, typename _ExtractKey, typename _Equal,
1898  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1899  typename _Traits>
1900  void
1901  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1902  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1903  clear() noexcept
1904  {
1905  this->_M_deallocate_nodes(_M_begin());
1906  __builtin_memset(_M_buckets, 0, _M_bucket_count * sizeof(__bucket_type));
1907  _M_element_count = 0;
1908  _M_before_begin._M_nxt = nullptr;
1909  }
1910 
1911  template<typename _Key, typename _Value,
1912  typename _Alloc, typename _ExtractKey, typename _Equal,
1913  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1914  typename _Traits>
1915  void
1916  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1917  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1918  rehash(size_type __n)
1919  {
1920  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
1921  std::size_t __buckets
1922  = std::max(_M_rehash_policy._M_bkt_for_elements(_M_element_count + 1),
1923  __n);
1924  __buckets = _M_rehash_policy._M_next_bkt(__buckets);
1925 
1926  if (__buckets != _M_bucket_count)
1927  _M_rehash(__buckets, __saved_state);
1928  else
1929  // No rehash, restore previous state to keep a consistent state.
1930  _M_rehash_policy._M_reset(__saved_state);
1931  }
1932 
1933  template<typename _Key, typename _Value,
1934  typename _Alloc, typename _ExtractKey, typename _Equal,
1935  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1936  typename _Traits>
1937  void
1938  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1939  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1940  _M_rehash(size_type __n, const __rehash_state& __state)
1941  {
1942  __try
1943  {
1944  _M_rehash_aux(__n, __unique_keys());
1945  }
1946  __catch(...)
1947  {
1948  // A failure here means that buckets allocation failed. We only
1949  // have to restore hash policy previous state.
1950  _M_rehash_policy._M_reset(__state);
1951  __throw_exception_again;
1952  }
1953  }
1954 
1955  // Rehash when there is no equivalent elements.
1956  template<typename _Key, typename _Value,
1957  typename _Alloc, typename _ExtractKey, typename _Equal,
1958  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1959  typename _Traits>
1960  void
1961  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1962  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1963  _M_rehash_aux(size_type __n, std::true_type)
1964  {
1965  __bucket_type* __new_buckets = _M_allocate_buckets(__n);
1966  __node_type* __p = _M_begin();
1967  _M_before_begin._M_nxt = nullptr;
1968  std::size_t __bbegin_bkt = 0;
1969  while (__p)
1970  {
1971  __node_type* __next = __p->_M_next();
1972  std::size_t __bkt = __hash_code_base::_M_bucket_index(__p, __n);
1973  if (!__new_buckets[__bkt])
1974  {
1975  __p->_M_nxt = _M_before_begin._M_nxt;
1976  _M_before_begin._M_nxt = __p;
1977  __new_buckets[__bkt] = &_M_before_begin;
1978  if (__p->_M_nxt)
1979  __new_buckets[__bbegin_bkt] = __p;
1980  __bbegin_bkt = __bkt;
1981  }
1982  else
1983  {
1984  __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
1985  __new_buckets[__bkt]->_M_nxt = __p;
1986  }
1987  __p = __next;
1988  }
1989 
1990  _M_deallocate_buckets();
1991  _M_bucket_count = __n;
1992  _M_buckets = __new_buckets;
1993  }
1994 
1995  // Rehash when there can be equivalent elements, preserve their relative
1996  // order.
1997  template<typename _Key, typename _Value,
1998  typename _Alloc, typename _ExtractKey, typename _Equal,
1999  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
2000  typename _Traits>
2001  void
2002  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2003  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
2004  _M_rehash_aux(size_type __n, std::false_type)
2005  {
2006  __bucket_type* __new_buckets = _M_allocate_buckets(__n);
2007 
2008  __node_type* __p = _M_begin();
2009  _M_before_begin._M_nxt = nullptr;
2010  std::size_t __bbegin_bkt = 0;
2011  std::size_t __prev_bkt = 0;
2012  __node_type* __prev_p = nullptr;
2013  bool __check_bucket = false;
2014 
2015  while (__p)
2016  {
2017  __node_type* __next = __p->_M_next();
2018  std::size_t __bkt = __hash_code_base::_M_bucket_index(__p, __n);
2019 
2020  if (__prev_p && __prev_bkt == __bkt)
2021  {
2022  // Previous insert was already in this bucket, we insert after
2023  // the previously inserted one to preserve equivalent elements
2024  // relative order.
2025  __p->_M_nxt = __prev_p->_M_nxt;
2026  __prev_p->_M_nxt = __p;
2027 
2028  // Inserting after a node in a bucket require to check that we
2029  // haven't change the bucket last node, in this case next
2030  // bucket containing its before begin node must be updated. We
2031  // schedule a check as soon as we move out of the sequence of
2032  // equivalent nodes to limit the number of checks.
2033  __check_bucket = true;
2034  }
2035  else
2036  {
2037  if (__check_bucket)
2038  {
2039  // Check if we shall update the next bucket because of
2040  // insertions into __prev_bkt bucket.
2041  if (__prev_p->_M_nxt)
2042  {
2043  std::size_t __next_bkt
2044  = __hash_code_base::_M_bucket_index(__prev_p->_M_next(),
2045  __n);
2046  if (__next_bkt != __prev_bkt)
2047  __new_buckets[__next_bkt] = __prev_p;
2048  }
2049  __check_bucket = false;
2050  }
2051 
2052  if (!__new_buckets[__bkt])
2053  {
2054  __p->_M_nxt = _M_before_begin._M_nxt;
2055  _M_before_begin._M_nxt = __p;
2056  __new_buckets[__bkt] = &_M_before_begin;
2057  if (__p->_M_nxt)
2058  __new_buckets[__bbegin_bkt] = __p;
2059  __bbegin_bkt = __bkt;
2060  }
2061  else
2062  {
2063  __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
2064  __new_buckets[__bkt]->_M_nxt = __p;
2065  }
2066  }
2067  __prev_p = __p;
2068  __prev_bkt = __bkt;
2069  __p = __next;
2070  }
2071 
2072  if (__check_bucket && __prev_p->_M_nxt)
2073  {
2074  std::size_t __next_bkt
2075  = __hash_code_base::_M_bucket_index(__prev_p->_M_next(), __n);
2076  if (__next_bkt != __prev_bkt)
2077  __new_buckets[__next_bkt] = __prev_p;
2078  }
2079 
2080  _M_deallocate_buckets();
2081  _M_bucket_count = __n;
2082  _M_buckets = __new_buckets;
2083  }
2084 
2085 _GLIBCXX_END_NAMESPACE_VERSION
2086 } // namespace std
2087 
2088 #endif // _HASHTABLE_H
integral_constant
Definition: type_traits:69
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:116
Uniform interface to all allocator types.
iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
_GLIBCXX14_CONSTEXPR const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:219
Node iterators, used to iterate through all the hashtable.
initializer_list
_T2 second
first is a copy of the first object
Definition: stl_pair.h:102
Uniform interface to C++98 and C++0x allocators.
ISO C++ entities toplevel namespace is std.
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
Node const_iterators, used to iterate through all the hashtable.
Struct holding two objects of arbitrary type.
Definition: stl_pair.h:96
constexpr const _Tp * begin(initializer_list< _Tp > __ils) noexcept
Return an iterator pointing to the first element of the initializer_list.
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:127
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
constexpr const _Tp * end(initializer_list< _Tp > __ils) noexcept
Return an iterator pointing to one past the last element of the initializer_list. ...
_T1 first
second_type is the second bound type
Definition: stl_pair.h:101
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:87