libstdc++
bits/hashtable.h
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1 // hashtable.h header -*- C++ -*-
2 
3 // Copyright (C) 2007-2017 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
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18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
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22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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24 
25 /** @file bits/hashtable.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{unordered_map, unordered_set}
28  */
29 
30 #ifndef _HASHTABLE_H
31 #define _HASHTABLE_H 1
32 
33 #pragma GCC system_header
34 
35 #include <bits/hashtable_policy.h>
36 #if __cplusplus > 201402L
37 # include <bits/node_handle.h>
38 #endif
39 
40 namespace std _GLIBCXX_VISIBILITY(default)
41 {
42 _GLIBCXX_BEGIN_NAMESPACE_VERSION
43 
44  template<typename _Tp, typename _Hash>
45  using __cache_default
46  = __not_<__and_<// Do not cache for fast hasher.
47  __is_fast_hash<_Hash>,
48  // Mandatory to have erase not throwing.
49  __detail::__is_noexcept_hash<_Tp, _Hash>>>;
50 
51  /**
52  * Primary class template _Hashtable.
53  *
54  * @ingroup hashtable-detail
55  *
56  * @tparam _Value CopyConstructible type.
57  *
58  * @tparam _Key CopyConstructible type.
59  *
60  * @tparam _Alloc An allocator type
61  * ([lib.allocator.requirements]) whose _Alloc::value_type is
62  * _Value. As a conforming extension, we allow for
63  * _Alloc::value_type != _Value.
64  *
65  * @tparam _ExtractKey Function object that takes an object of type
66  * _Value and returns a value of type _Key.
67  *
68  * @tparam _Equal Function object that takes two objects of type k
69  * and returns a bool-like value that is true if the two objects
70  * are considered equal.
71  *
72  * @tparam _H1 The hash function. A unary function object with
73  * argument type _Key and result type size_t. Return values should
74  * be distributed over the entire range [0, numeric_limits<size_t>:::max()].
75  *
76  * @tparam _H2 The range-hashing function (in the terminology of
77  * Tavori and Dreizin). A binary function object whose argument
78  * types and result type are all size_t. Given arguments r and N,
79  * the return value is in the range [0, N).
80  *
81  * @tparam _Hash The ranged hash function (Tavori and Dreizin). A
82  * binary function whose argument types are _Key and size_t and
83  * whose result type is size_t. Given arguments k and N, the
84  * return value is in the range [0, N). Default: hash(k, N) =
85  * h2(h1(k), N). If _Hash is anything other than the default, _H1
86  * and _H2 are ignored.
87  *
88  * @tparam _RehashPolicy Policy class with three members, all of
89  * which govern the bucket count. _M_next_bkt(n) returns a bucket
90  * count no smaller than n. _M_bkt_for_elements(n) returns a
91  * bucket count appropriate for an element count of n.
92  * _M_need_rehash(n_bkt, n_elt, n_ins) determines whether, if the
93  * current bucket count is n_bkt and the current element count is
94  * n_elt, we need to increase the bucket count. If so, returns
95  * make_pair(true, n), where n is the new bucket count. If not,
96  * returns make_pair(false, <anything>)
97  *
98  * @tparam _Traits Compile-time class with three boolean
99  * std::integral_constant members: __cache_hash_code, __constant_iterators,
100  * __unique_keys.
101  *
102  * Each _Hashtable data structure has:
103  *
104  * - _Bucket[] _M_buckets
105  * - _Hash_node_base _M_before_begin
106  * - size_type _M_bucket_count
107  * - size_type _M_element_count
108  *
109  * with _Bucket being _Hash_node* and _Hash_node containing:
110  *
111  * - _Hash_node* _M_next
112  * - Tp _M_value
113  * - size_t _M_hash_code if cache_hash_code is true
114  *
115  * In terms of Standard containers the hashtable is like the aggregation of:
116  *
117  * - std::forward_list<_Node> containing the elements
118  * - std::vector<std::forward_list<_Node>::iterator> representing the buckets
119  *
120  * The non-empty buckets contain the node before the first node in the
121  * bucket. This design makes it possible to implement something like a
122  * std::forward_list::insert_after on container insertion and
123  * std::forward_list::erase_after on container erase
124  * calls. _M_before_begin is equivalent to
125  * std::forward_list::before_begin. Empty buckets contain
126  * nullptr. Note that one of the non-empty buckets contains
127  * &_M_before_begin which is not a dereferenceable node so the
128  * node pointer in a bucket shall never be dereferenced, only its
129  * next node can be.
130  *
131  * Walking through a bucket's nodes requires a check on the hash code to
132  * see if each node is still in the bucket. Such a design assumes a
133  * quite efficient hash functor and is one of the reasons it is
134  * highly advisable to set __cache_hash_code to true.
135  *
136  * The container iterators are simply built from nodes. This way
137  * incrementing the iterator is perfectly efficient independent of
138  * how many empty buckets there are in the container.
139  *
140  * On insert we compute the element's hash code and use it to find the
141  * bucket index. If the element must be inserted in an empty bucket
142  * we add it at the beginning of the singly linked list and make the
143  * bucket point to _M_before_begin. The bucket that used to point to
144  * _M_before_begin, if any, is updated to point to its new before
145  * begin node.
146  *
147  * On erase, the simple iterator design requires using the hash
148  * functor to get the index of the bucket to update. For this
149  * reason, when __cache_hash_code is set to false the hash functor must
150  * not throw and this is enforced by a static assertion.
151  *
152  * Functionality is implemented by decomposition into base classes,
153  * where the derived _Hashtable class is used in _Map_base,
154  * _Insert, _Rehash_base, and _Equality base classes to access the
155  * "this" pointer. _Hashtable_base is used in the base classes as a
156  * non-recursive, fully-completed-type so that detailed nested type
157  * information, such as iterator type and node type, can be
158  * used. This is similar to the "Curiously Recurring Template
159  * Pattern" (CRTP) technique, but uses a reconstructed, not
160  * explicitly passed, template pattern.
161  *
162  * Base class templates are:
163  * - __detail::_Hashtable_base
164  * - __detail::_Map_base
165  * - __detail::_Insert
166  * - __detail::_Rehash_base
167  * - __detail::_Equality
168  */
169  template<typename _Key, typename _Value, typename _Alloc,
170  typename _ExtractKey, typename _Equal,
171  typename _H1, typename _H2, typename _Hash,
172  typename _RehashPolicy, typename _Traits>
174  : public __detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal,
175  _H1, _H2, _Hash, _Traits>,
176  public __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
177  _H1, _H2, _Hash, _RehashPolicy, _Traits>,
178  public __detail::_Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
179  _H1, _H2, _Hash, _RehashPolicy, _Traits>,
180  public __detail::_Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
181  _H1, _H2, _Hash, _RehashPolicy, _Traits>,
182  public __detail::_Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
183  _H1, _H2, _Hash, _RehashPolicy, _Traits>,
185  __alloc_rebind<_Alloc,
186  __detail::_Hash_node<_Value,
187  _Traits::__hash_cached::value>>>
188  {
189  using __traits_type = _Traits;
190  using __hash_cached = typename __traits_type::__hash_cached;
192  using __node_alloc_type = __alloc_rebind<_Alloc, __node_type>;
193 
195 
196  using __value_alloc_traits =
198  using __node_alloc_traits =
200  using __node_base = typename __hashtable_alloc::__node_base;
201  using __bucket_type = typename __hashtable_alloc::__bucket_type;
202 
203  public:
204  typedef _Key key_type;
205  typedef _Value value_type;
206  typedef _Alloc allocator_type;
207  typedef _Equal key_equal;
208 
209  // mapped_type, if present, comes from _Map_base.
210  // hasher, if present, comes from _Hash_code_base/_Hashtable_base.
211  typedef typename __value_alloc_traits::pointer pointer;
212  typedef typename __value_alloc_traits::const_pointer const_pointer;
213  typedef value_type& reference;
214  typedef const value_type& const_reference;
215 
216  private:
217  using __rehash_type = _RehashPolicy;
218  using __rehash_state = typename __rehash_type::_State;
219 
220  using __constant_iterators = typename __traits_type::__constant_iterators;
221  using __unique_keys = typename __traits_type::__unique_keys;
222 
223  using __key_extract = typename std::conditional<
224  __constant_iterators::value,
225  __detail::_Identity,
226  __detail::_Select1st>::type;
227 
228  using __hashtable_base = __detail::
229  _Hashtable_base<_Key, _Value, _ExtractKey,
230  _Equal, _H1, _H2, _Hash, _Traits>;
231 
232  using __hash_code_base = typename __hashtable_base::__hash_code_base;
233  using __hash_code = typename __hashtable_base::__hash_code;
234  using __ireturn_type = typename __hashtable_base::__ireturn_type;
235 
236  using __map_base = __detail::_Map_base<_Key, _Value, _Alloc, _ExtractKey,
237  _Equal, _H1, _H2, _Hash,
238  _RehashPolicy, _Traits>;
239 
240  using __rehash_base = __detail::_Rehash_base<_Key, _Value, _Alloc,
241  _ExtractKey, _Equal,
242  _H1, _H2, _Hash,
243  _RehashPolicy, _Traits>;
244 
245  using __eq_base = __detail::_Equality<_Key, _Value, _Alloc, _ExtractKey,
246  _Equal, _H1, _H2, _Hash,
247  _RehashPolicy, _Traits>;
248 
249  using __reuse_or_alloc_node_type =
250  __detail::_ReuseOrAllocNode<__node_alloc_type>;
251 
252  // Metaprogramming for picking apart hash caching.
253  template<typename _Cond>
254  using __if_hash_cached = __or_<__not_<__hash_cached>, _Cond>;
255 
256  template<typename _Cond>
257  using __if_hash_not_cached = __or_<__hash_cached, _Cond>;
258 
259  // Compile-time diagnostics.
260 
261  // _Hash_code_base has everything protected, so use this derived type to
262  // access it.
263  struct __hash_code_base_access : __hash_code_base
264  { using __hash_code_base::_M_bucket_index; };
265 
266  // Getting a bucket index from a node shall not throw because it is used
267  // in methods (erase, swap...) that shall not throw.
268  static_assert(noexcept(declval<const __hash_code_base_access&>()
269  ._M_bucket_index((const __node_type*)nullptr,
270  (std::size_t)0)),
271  "Cache the hash code or qualify your functors involved"
272  " in hash code and bucket index computation with noexcept");
273 
274  // Following two static assertions are necessary to guarantee
275  // that local_iterator will be default constructible.
276 
277  // When hash codes are cached local iterator inherits from H2 functor
278  // which must then be default constructible.
279  static_assert(__if_hash_cached<is_default_constructible<_H2>>::value,
280  "Functor used to map hash code to bucket index"
281  " must be default constructible");
282 
283  template<typename _Keya, typename _Valuea, typename _Alloca,
284  typename _ExtractKeya, typename _Equala,
285  typename _H1a, typename _H2a, typename _Hasha,
286  typename _RehashPolicya, typename _Traitsa,
287  bool _Unique_keysa>
288  friend struct __detail::_Map_base;
289 
290  template<typename _Keya, typename _Valuea, typename _Alloca,
291  typename _ExtractKeya, typename _Equala,
292  typename _H1a, typename _H2a, typename _Hasha,
293  typename _RehashPolicya, typename _Traitsa>
294  friend struct __detail::_Insert_base;
295 
296  template<typename _Keya, typename _Valuea, typename _Alloca,
297  typename _ExtractKeya, typename _Equala,
298  typename _H1a, typename _H2a, typename _Hasha,
299  typename _RehashPolicya, typename _Traitsa,
300  bool _Constant_iteratorsa>
301  friend struct __detail::_Insert;
302 
303  public:
304  using size_type = typename __hashtable_base::size_type;
305  using difference_type = typename __hashtable_base::difference_type;
306 
307  using iterator = typename __hashtable_base::iterator;
308  using const_iterator = typename __hashtable_base::const_iterator;
309 
310  using local_iterator = typename __hashtable_base::local_iterator;
311  using const_local_iterator = typename __hashtable_base::
312  const_local_iterator;
313 
314 #if __cplusplus > 201402L
315  using node_type = _Node_handle<_Key, _Value, __node_alloc_type>;
316  using insert_return_type = _Node_insert_return<iterator, node_type>;
317 #endif
318 
319  private:
320  __bucket_type* _M_buckets = &_M_single_bucket;
321  size_type _M_bucket_count = 1;
322  __node_base _M_before_begin;
323  size_type _M_element_count = 0;
324  _RehashPolicy _M_rehash_policy;
325 
326  // A single bucket used when only need for 1 bucket. Especially
327  // interesting in move semantic to leave hashtable with only 1 buckets
328  // which is not allocated so that we can have those operations noexcept
329  // qualified.
330  // Note that we can't leave hashtable with 0 bucket without adding
331  // numerous checks in the code to avoid 0 modulus.
332  __bucket_type _M_single_bucket = nullptr;
333 
334  bool
335  _M_uses_single_bucket(__bucket_type* __bkts) const
336  { return __builtin_expect(__bkts == &_M_single_bucket, false); }
337 
338  bool
339  _M_uses_single_bucket() const
340  { return _M_uses_single_bucket(_M_buckets); }
341 
343  _M_base_alloc() { return *this; }
344 
345  __bucket_type*
346  _M_allocate_buckets(size_type __n)
347  {
348  if (__builtin_expect(__n == 1, false))
349  {
350  _M_single_bucket = nullptr;
351  return &_M_single_bucket;
352  }
353 
354  return __hashtable_alloc::_M_allocate_buckets(__n);
355  }
356 
357  void
358  _M_deallocate_buckets(__bucket_type* __bkts, size_type __n)
359  {
360  if (_M_uses_single_bucket(__bkts))
361  return;
362 
363  __hashtable_alloc::_M_deallocate_buckets(__bkts, __n);
364  }
365 
366  void
367  _M_deallocate_buckets()
368  { _M_deallocate_buckets(_M_buckets, _M_bucket_count); }
369 
370  // Gets bucket begin, deals with the fact that non-empty buckets contain
371  // their before begin node.
372  __node_type*
373  _M_bucket_begin(size_type __bkt) const;
374 
375  __node_type*
376  _M_begin() const
377  { return static_cast<__node_type*>(_M_before_begin._M_nxt); }
378 
379  template<typename _NodeGenerator>
380  void
381  _M_assign(const _Hashtable&, const _NodeGenerator&);
382 
383  void
384  _M_move_assign(_Hashtable&&, std::true_type);
385 
386  void
387  _M_move_assign(_Hashtable&&, std::false_type);
388 
389  void
390  _M_reset() noexcept;
391 
392  _Hashtable(const _H1& __h1, const _H2& __h2, const _Hash& __h,
393  const _Equal& __eq, const _ExtractKey& __exk,
394  const allocator_type& __a)
395  : __hashtable_base(__exk, __h1, __h2, __h, __eq),
396  __hashtable_alloc(__node_alloc_type(__a))
397  { }
398 
399  public:
400  // Constructor, destructor, assignment, swap
401  _Hashtable() = default;
402  _Hashtable(size_type __bucket_hint,
403  const _H1&, const _H2&, const _Hash&,
404  const _Equal&, const _ExtractKey&,
405  const allocator_type&);
406 
407  template<typename _InputIterator>
408  _Hashtable(_InputIterator __first, _InputIterator __last,
409  size_type __bucket_hint,
410  const _H1&, const _H2&, const _Hash&,
411  const _Equal&, const _ExtractKey&,
412  const allocator_type&);
413 
414  _Hashtable(const _Hashtable&);
415 
416  _Hashtable(_Hashtable&&) noexcept;
417 
418  _Hashtable(const _Hashtable&, const allocator_type&);
419 
420  _Hashtable(_Hashtable&&, const allocator_type&);
421 
422  // Use delegating constructors.
423  explicit
424  _Hashtable(const allocator_type& __a)
425  : __hashtable_alloc(__node_alloc_type(__a))
426  { }
427 
428  explicit
429  _Hashtable(size_type __n,
430  const _H1& __hf = _H1(),
431  const key_equal& __eql = key_equal(),
432  const allocator_type& __a = allocator_type())
433  : _Hashtable(__n, __hf, _H2(), _Hash(), __eql,
434  __key_extract(), __a)
435  { }
436 
437  template<typename _InputIterator>
438  _Hashtable(_InputIterator __f, _InputIterator __l,
439  size_type __n = 0,
440  const _H1& __hf = _H1(),
441  const key_equal& __eql = key_equal(),
442  const allocator_type& __a = allocator_type())
443  : _Hashtable(__f, __l, __n, __hf, _H2(), _Hash(), __eql,
444  __key_extract(), __a)
445  { }
446 
448  size_type __n = 0,
449  const _H1& __hf = _H1(),
450  const key_equal& __eql = key_equal(),
451  const allocator_type& __a = allocator_type())
452  : _Hashtable(__l.begin(), __l.end(), __n, __hf, _H2(), _Hash(), __eql,
453  __key_extract(), __a)
454  { }
455 
456  _Hashtable&
457  operator=(const _Hashtable& __ht);
458 
459  _Hashtable&
460  operator=(_Hashtable&& __ht)
461  noexcept(__node_alloc_traits::_S_nothrow_move()
462  && is_nothrow_move_assignable<_H1>::value
463  && is_nothrow_move_assignable<_Equal>::value)
464  {
465  constexpr bool __move_storage =
466  __node_alloc_traits::_S_propagate_on_move_assign()
467  || __node_alloc_traits::_S_always_equal();
468  _M_move_assign(std::move(__ht), __bool_constant<__move_storage>());
469  return *this;
470  }
471 
472  _Hashtable&
473  operator=(initializer_list<value_type> __l)
474  {
475  __reuse_or_alloc_node_type __roan(_M_begin(), *this);
476  _M_before_begin._M_nxt = nullptr;
477  clear();
478  this->_M_insert_range(__l.begin(), __l.end(), __roan);
479  return *this;
480  }
481 
482  ~_Hashtable() noexcept;
483 
484  void
485  swap(_Hashtable&)
486  noexcept(__and_<__is_nothrow_swappable<_H1>,
487  __is_nothrow_swappable<_Equal>>::value);
488 
489  // Basic container operations
490  iterator
491  begin() noexcept
492  { return iterator(_M_begin()); }
493 
494  const_iterator
495  begin() const noexcept
496  { return const_iterator(_M_begin()); }
497 
498  iterator
499  end() noexcept
500  { return iterator(nullptr); }
501 
502  const_iterator
503  end() const noexcept
504  { return const_iterator(nullptr); }
505 
506  const_iterator
507  cbegin() const noexcept
508  { return const_iterator(_M_begin()); }
509 
510  const_iterator
511  cend() const noexcept
512  { return const_iterator(nullptr); }
513 
514  size_type
515  size() const noexcept
516  { return _M_element_count; }
517 
518  bool
519  empty() const noexcept
520  { return size() == 0; }
521 
522  allocator_type
523  get_allocator() const noexcept
524  { return allocator_type(this->_M_node_allocator()); }
525 
526  size_type
527  max_size() const noexcept
528  { return __node_alloc_traits::max_size(this->_M_node_allocator()); }
529 
530  // Observers
531  key_equal
532  key_eq() const
533  { return this->_M_eq(); }
534 
535  // hash_function, if present, comes from _Hash_code_base.
536 
537  // Bucket operations
538  size_type
539  bucket_count() const noexcept
540  { return _M_bucket_count; }
541 
542  size_type
543  max_bucket_count() const noexcept
544  { return max_size(); }
545 
546  size_type
547  bucket_size(size_type __n) const
548  { return std::distance(begin(__n), end(__n)); }
549 
550  size_type
551  bucket(const key_type& __k) const
552  { return _M_bucket_index(__k, this->_M_hash_code(__k)); }
553 
554  local_iterator
555  begin(size_type __n)
556  {
557  return local_iterator(*this, _M_bucket_begin(__n),
558  __n, _M_bucket_count);
559  }
560 
561  local_iterator
562  end(size_type __n)
563  { return local_iterator(*this, nullptr, __n, _M_bucket_count); }
564 
565  const_local_iterator
566  begin(size_type __n) const
567  {
568  return const_local_iterator(*this, _M_bucket_begin(__n),
569  __n, _M_bucket_count);
570  }
571 
572  const_local_iterator
573  end(size_type __n) const
574  { return const_local_iterator(*this, nullptr, __n, _M_bucket_count); }
575 
576  // DR 691.
577  const_local_iterator
578  cbegin(size_type __n) const
579  {
580  return const_local_iterator(*this, _M_bucket_begin(__n),
581  __n, _M_bucket_count);
582  }
583 
584  const_local_iterator
585  cend(size_type __n) const
586  { return const_local_iterator(*this, nullptr, __n, _M_bucket_count); }
587 
588  float
589  load_factor() const noexcept
590  {
591  return static_cast<float>(size()) / static_cast<float>(bucket_count());
592  }
593 
594  // max_load_factor, if present, comes from _Rehash_base.
595 
596  // Generalization of max_load_factor. Extension, not found in
597  // TR1. Only useful if _RehashPolicy is something other than
598  // the default.
599  const _RehashPolicy&
600  __rehash_policy() const
601  { return _M_rehash_policy; }
602 
603  void
604  __rehash_policy(const _RehashPolicy& __pol)
605  { _M_rehash_policy = __pol; }
606 
607  // Lookup.
608  iterator
609  find(const key_type& __k);
610 
611  const_iterator
612  find(const key_type& __k) const;
613 
614  size_type
615  count(const key_type& __k) const;
616 
618  equal_range(const key_type& __k);
619 
621  equal_range(const key_type& __k) const;
622 
623  protected:
624  // Bucket index computation helpers.
625  size_type
626  _M_bucket_index(__node_type* __n) const noexcept
627  { return __hash_code_base::_M_bucket_index(__n, _M_bucket_count); }
628 
629  size_type
630  _M_bucket_index(const key_type& __k, __hash_code __c) const
631  { return __hash_code_base::_M_bucket_index(__k, __c, _M_bucket_count); }
632 
633  // Find and insert helper functions and types
634  // Find the node before the one matching the criteria.
635  __node_base*
636  _M_find_before_node(size_type, const key_type&, __hash_code) const;
637 
638  __node_type*
639  _M_find_node(size_type __bkt, const key_type& __key,
640  __hash_code __c) const
641  {
642  __node_base* __before_n = _M_find_before_node(__bkt, __key, __c);
643  if (__before_n)
644  return static_cast<__node_type*>(__before_n->_M_nxt);
645  return nullptr;
646  }
647 
648  // Insert a node at the beginning of a bucket.
649  void
650  _M_insert_bucket_begin(size_type, __node_type*);
651 
652  // Remove the bucket first node
653  void
654  _M_remove_bucket_begin(size_type __bkt, __node_type* __next_n,
655  size_type __next_bkt);
656 
657  // Get the node before __n in the bucket __bkt
658  __node_base*
659  _M_get_previous_node(size_type __bkt, __node_base* __n);
660 
661  // Insert node with hash code __code, in bucket bkt if no rehash (assumes
662  // no element with its key already present). Take ownership of the node,
663  // deallocate it on exception.
664  iterator
665  _M_insert_unique_node(size_type __bkt, __hash_code __code,
666  __node_type* __n);
667 
668  // Insert node with hash code __code. Take ownership of the node,
669  // deallocate it on exception.
670  iterator
671  _M_insert_multi_node(__node_type* __hint,
672  __hash_code __code, __node_type* __n);
673 
674  template<typename... _Args>
676  _M_emplace(std::true_type, _Args&&... __args);
677 
678  template<typename... _Args>
679  iterator
680  _M_emplace(std::false_type __uk, _Args&&... __args)
681  { return _M_emplace(cend(), __uk, std::forward<_Args>(__args)...); }
682 
683  // Emplace with hint, useless when keys are unique.
684  template<typename... _Args>
685  iterator
686  _M_emplace(const_iterator, std::true_type __uk, _Args&&... __args)
687  { return _M_emplace(__uk, std::forward<_Args>(__args)...).first; }
688 
689  template<typename... _Args>
690  iterator
691  _M_emplace(const_iterator, std::false_type, _Args&&... __args);
692 
693  template<typename _Arg, typename _NodeGenerator>
695  _M_insert(_Arg&&, const _NodeGenerator&, std::true_type);
696 
697  template<typename _Arg, typename _NodeGenerator>
698  iterator
699  _M_insert(_Arg&& __arg, const _NodeGenerator& __node_gen,
700  std::false_type __uk)
701  {
702  return _M_insert(cend(), std::forward<_Arg>(__arg), __node_gen,
703  __uk);
704  }
705 
706  // Insert with hint, not used when keys are unique.
707  template<typename _Arg, typename _NodeGenerator>
708  iterator
709  _M_insert(const_iterator, _Arg&& __arg,
710  const _NodeGenerator& __node_gen, std::true_type __uk)
711  {
712  return
713  _M_insert(std::forward<_Arg>(__arg), __node_gen, __uk).first;
714  }
715 
716  // Insert with hint when keys are not unique.
717  template<typename _Arg, typename _NodeGenerator>
718  iterator
719  _M_insert(const_iterator, _Arg&&,
720  const _NodeGenerator&, std::false_type);
721 
722  size_type
723  _M_erase(std::true_type, const key_type&);
724 
725  size_type
726  _M_erase(std::false_type, const key_type&);
727 
728  iterator
729  _M_erase(size_type __bkt, __node_base* __prev_n, __node_type* __n);
730 
731  public:
732  // Emplace
733  template<typename... _Args>
734  __ireturn_type
735  emplace(_Args&&... __args)
736  { return _M_emplace(__unique_keys(), std::forward<_Args>(__args)...); }
737 
738  template<typename... _Args>
739  iterator
740  emplace_hint(const_iterator __hint, _Args&&... __args)
741  {
742  return _M_emplace(__hint, __unique_keys(),
743  std::forward<_Args>(__args)...);
744  }
745 
746  // Insert member functions via inheritance.
747 
748  // Erase
749  iterator
750  erase(const_iterator);
751 
752  // LWG 2059.
753  iterator
754  erase(iterator __it)
755  { return erase(const_iterator(__it)); }
756 
757  size_type
758  erase(const key_type& __k)
759  { return _M_erase(__unique_keys(), __k); }
760 
761  iterator
762  erase(const_iterator, const_iterator);
763 
764  void
765  clear() noexcept;
766 
767  // Set number of buckets to be appropriate for container of n element.
768  void rehash(size_type __n);
769 
770  // DR 1189.
771  // reserve, if present, comes from _Rehash_base.
772 
773 #if __cplusplus > 201402L
774  /// Re-insert an extracted node into a container with unique keys.
775  insert_return_type
776  _M_reinsert_node(node_type&& __nh)
777  {
778  insert_return_type __ret;
779  if (__nh.empty())
780  __ret.position = end();
781  else
782  {
783  __glibcxx_assert(get_allocator() == __nh.get_allocator());
784 
785  const key_type& __k = __nh._M_key();
786  __hash_code __code = this->_M_hash_code(__k);
787  size_type __bkt = _M_bucket_index(__k, __code);
788  if (__node_type* __n = _M_find_node(__bkt, __k, __code))
789  {
790  __ret.node = std::move(__nh);
791  __ret.position = iterator(__n);
792  __ret.inserted = false;
793  }
794  else
795  {
796  __ret.position
797  = _M_insert_unique_node(__bkt, __code, __nh._M_ptr);
798  __nh._M_ptr = nullptr;
799  __ret.inserted = true;
800  }
801  }
802  return __ret;
803  }
804 
805  /// Re-insert an extracted node into a container with equivalent keys.
806  iterator
807  _M_reinsert_node_multi(const_iterator __hint, node_type&& __nh)
808  {
809  iterator __ret;
810  if (__nh.empty())
811  __ret = end();
812  else
813  {
814  __glibcxx_assert(get_allocator() == __nh.get_allocator());
815 
816  auto __code = this->_M_hash_code(__nh._M_key());
817  auto __node = std::exchange(__nh._M_ptr, nullptr);
818  // FIXME: this deallocates the node on exception.
819  __ret = _M_insert_multi_node(__hint._M_cur, __code, __node);
820  }
821  return __ret;
822  }
823 
824  /// Extract a node.
825  node_type
826  extract(const_iterator __pos)
827  {
828  __node_type* __n = __pos._M_cur;
829  size_t __bkt = _M_bucket_index(__n);
830 
831  // Look for previous node to unlink it from the erased one, this
832  // is why we need buckets to contain the before begin to make
833  // this search fast.
834  __node_base* __prev_n = _M_get_previous_node(__bkt, __n);
835 
836  if (__prev_n == _M_buckets[__bkt])
837  _M_remove_bucket_begin(__bkt, __n->_M_next(),
838  __n->_M_nxt ? _M_bucket_index(__n->_M_next()) : 0);
839  else if (__n->_M_nxt)
840  {
841  size_type __next_bkt = _M_bucket_index(__n->_M_next());
842  if (__next_bkt != __bkt)
843  _M_buckets[__next_bkt] = __prev_n;
844  }
845 
846  __prev_n->_M_nxt = __n->_M_nxt;
847  __n->_M_nxt = nullptr;
848  --_M_element_count;
849  return { __n, this->_M_node_allocator() };
850  }
851 
852  /// Extract a node.
853  node_type
854  extract(const _Key& __k)
855  {
856  node_type __nh;
857  auto __pos = find(__k);
858  if (__pos != end())
859  __nh = extract(const_iterator(__pos));
860  return __nh;
861  }
862 
863  /// Merge from a compatible container into one with unique keys.
864  template<typename _Compatible_Hashtable>
865  void
866  _M_merge_unique(_Compatible_Hashtable& __src) noexcept
867  {
868  static_assert(is_same_v<typename _Compatible_Hashtable::node_type,
869  node_type>, "Node types are compatible");
870  __glibcxx_assert(get_allocator() == __src.get_allocator());
871 
872  for (auto __i = __src.begin(), __end = __src.end(); __i != __end;)
873  {
874  auto __pos = __i++;
875  const key_type& __k = this->_M_extract()(__pos._M_cur->_M_v());
876  __hash_code __code = this->_M_hash_code(__k);
877  size_type __bkt = _M_bucket_index(__k, __code);
878  if (_M_find_node(__bkt, __k, __code) == nullptr)
879  {
880  auto __nh = __src.extract(__pos);
881  _M_insert_unique_node(__bkt, __code, __nh._M_ptr);
882  __nh._M_ptr = nullptr;
883  }
884  }
885  }
886 
887  /// Merge from a compatible container into one with equivalent keys.
888  template<typename _Compatible_Hashtable>
889  void
890  _M_merge_multi(_Compatible_Hashtable& __src) noexcept
891  {
892  static_assert(is_same_v<typename _Compatible_Hashtable::node_type,
893  node_type>, "Node types are compatible");
894  __glibcxx_assert(get_allocator() == __src.get_allocator());
895 
896  this->reserve(size() + __src.size());
897  for (auto __i = __src.begin(), __end = __src.end(); __i != __end;)
898  _M_reinsert_node_multi(cend(), __src.extract(__i++));
899  }
900 #endif // C++17
901 
902  private:
903  // Helper rehash method used when keys are unique.
904  void _M_rehash_aux(size_type __n, std::true_type);
905 
906  // Helper rehash method used when keys can be non-unique.
907  void _M_rehash_aux(size_type __n, std::false_type);
908 
909  // Unconditionally change size of bucket array to n, restore
910  // hash policy state to __state on exception.
911  void _M_rehash(size_type __n, const __rehash_state& __state);
912  };
913 
914 
915  // Definitions of class template _Hashtable's out-of-line member functions.
916  template<typename _Key, typename _Value,
917  typename _Alloc, typename _ExtractKey, typename _Equal,
918  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
919  typename _Traits>
920  auto
921  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
922  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
923  _M_bucket_begin(size_type __bkt) const
924  -> __node_type*
925  {
926  __node_base* __n = _M_buckets[__bkt];
927  return __n ? static_cast<__node_type*>(__n->_M_nxt) : nullptr;
928  }
929 
930  template<typename _Key, typename _Value,
931  typename _Alloc, typename _ExtractKey, typename _Equal,
932  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
933  typename _Traits>
934  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
935  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
936  _Hashtable(size_type __bucket_hint,
937  const _H1& __h1, const _H2& __h2, const _Hash& __h,
938  const _Equal& __eq, const _ExtractKey& __exk,
939  const allocator_type& __a)
940  : _Hashtable(__h1, __h2, __h, __eq, __exk, __a)
941  {
942  auto __bkt = _M_rehash_policy._M_next_bkt(__bucket_hint);
943  if (__bkt > _M_bucket_count)
944  {
945  _M_buckets = _M_allocate_buckets(__bkt);
946  _M_bucket_count = __bkt;
947  }
948  }
949 
950  template<typename _Key, typename _Value,
951  typename _Alloc, typename _ExtractKey, typename _Equal,
952  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
953  typename _Traits>
954  template<typename _InputIterator>
955  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
956  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
957  _Hashtable(_InputIterator __f, _InputIterator __l,
958  size_type __bucket_hint,
959  const _H1& __h1, const _H2& __h2, const _Hash& __h,
960  const _Equal& __eq, const _ExtractKey& __exk,
961  const allocator_type& __a)
962  : _Hashtable(__h1, __h2, __h, __eq, __exk, __a)
963  {
964  auto __nb_elems = __detail::__distance_fw(__f, __l);
965  auto __bkt_count =
966  _M_rehash_policy._M_next_bkt(
967  std::max(_M_rehash_policy._M_bkt_for_elements(__nb_elems),
968  __bucket_hint));
969 
970  if (__bkt_count > _M_bucket_count)
971  {
972  _M_buckets = _M_allocate_buckets(__bkt_count);
973  _M_bucket_count = __bkt_count;
974  }
975 
976  __try
977  {
978  for (; __f != __l; ++__f)
979  this->insert(*__f);
980  }
981  __catch(...)
982  {
983  clear();
984  _M_deallocate_buckets();
985  __throw_exception_again;
986  }
987  }
988 
989  template<typename _Key, typename _Value,
990  typename _Alloc, typename _ExtractKey, typename _Equal,
991  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
992  typename _Traits>
993  auto
994  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
995  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
996  operator=(const _Hashtable& __ht)
997  -> _Hashtable&
998  {
999  if (&__ht == this)
1000  return *this;
1001 
1002  if (__node_alloc_traits::_S_propagate_on_copy_assign())
1003  {
1004  auto& __this_alloc = this->_M_node_allocator();
1005  auto& __that_alloc = __ht._M_node_allocator();
1006  if (!__node_alloc_traits::_S_always_equal()
1007  && __this_alloc != __that_alloc)
1008  {
1009  // Replacement allocator cannot free existing storage.
1010  this->_M_deallocate_nodes(_M_begin());
1011  _M_before_begin._M_nxt = nullptr;
1012  _M_deallocate_buckets();
1013  _M_buckets = nullptr;
1014  std::__alloc_on_copy(__this_alloc, __that_alloc);
1015  __hashtable_base::operator=(__ht);
1016  _M_bucket_count = __ht._M_bucket_count;
1017  _M_element_count = __ht._M_element_count;
1018  _M_rehash_policy = __ht._M_rehash_policy;
1019  __try
1020  {
1021  _M_assign(__ht,
1022  [this](const __node_type* __n)
1023  { return this->_M_allocate_node(__n->_M_v()); });
1024  }
1025  __catch(...)
1026  {
1027  // _M_assign took care of deallocating all memory. Now we
1028  // must make sure this instance remains in a usable state.
1029  _M_reset();
1030  __throw_exception_again;
1031  }
1032  return *this;
1033  }
1034  std::__alloc_on_copy(__this_alloc, __that_alloc);
1035  }
1036 
1037  // Reuse allocated buckets and nodes.
1038  __bucket_type* __former_buckets = nullptr;
1039  std::size_t __former_bucket_count = _M_bucket_count;
1040  const __rehash_state& __former_state = _M_rehash_policy._M_state();
1041 
1042  if (_M_bucket_count != __ht._M_bucket_count)
1043  {
1044  __former_buckets = _M_buckets;
1045  _M_buckets = _M_allocate_buckets(__ht._M_bucket_count);
1046  _M_bucket_count = __ht._M_bucket_count;
1047  }
1048  else
1049  __builtin_memset(_M_buckets, 0,
1050  _M_bucket_count * sizeof(__bucket_type));
1051 
1052  __try
1053  {
1054  __hashtable_base::operator=(__ht);
1055  _M_element_count = __ht._M_element_count;
1056  _M_rehash_policy = __ht._M_rehash_policy;
1057  __reuse_or_alloc_node_type __roan(_M_begin(), *this);
1058  _M_before_begin._M_nxt = nullptr;
1059  _M_assign(__ht,
1060  [&__roan](const __node_type* __n)
1061  { return __roan(__n->_M_v()); });
1062  if (__former_buckets)
1063  _M_deallocate_buckets(__former_buckets, __former_bucket_count);
1064  }
1065  __catch(...)
1066  {
1067  if (__former_buckets)
1068  {
1069  // Restore previous buckets.
1070  _M_deallocate_buckets();
1071  _M_rehash_policy._M_reset(__former_state);
1072  _M_buckets = __former_buckets;
1073  _M_bucket_count = __former_bucket_count;
1074  }
1075  __builtin_memset(_M_buckets, 0,
1076  _M_bucket_count * sizeof(__bucket_type));
1077  __throw_exception_again;
1078  }
1079  return *this;
1080  }
1081 
1082  template<typename _Key, typename _Value,
1083  typename _Alloc, typename _ExtractKey, typename _Equal,
1084  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1085  typename _Traits>
1086  template<typename _NodeGenerator>
1087  void
1088  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1089  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1090  _M_assign(const _Hashtable& __ht, const _NodeGenerator& __node_gen)
1091  {
1092  __bucket_type* __buckets = nullptr;
1093  if (!_M_buckets)
1094  _M_buckets = __buckets = _M_allocate_buckets(_M_bucket_count);
1095 
1096  __try
1097  {
1098  if (!__ht._M_before_begin._M_nxt)
1099  return;
1100 
1101  // First deal with the special first node pointed to by
1102  // _M_before_begin.
1103  __node_type* __ht_n = __ht._M_begin();
1104  __node_type* __this_n = __node_gen(__ht_n);
1105  this->_M_copy_code(__this_n, __ht_n);
1106  _M_before_begin._M_nxt = __this_n;
1107  _M_buckets[_M_bucket_index(__this_n)] = &_M_before_begin;
1108 
1109  // Then deal with other nodes.
1110  __node_base* __prev_n = __this_n;
1111  for (__ht_n = __ht_n->_M_next(); __ht_n; __ht_n = __ht_n->_M_next())
1112  {
1113  __this_n = __node_gen(__ht_n);
1114  __prev_n->_M_nxt = __this_n;
1115  this->_M_copy_code(__this_n, __ht_n);
1116  size_type __bkt = _M_bucket_index(__this_n);
1117  if (!_M_buckets[__bkt])
1118  _M_buckets[__bkt] = __prev_n;
1119  __prev_n = __this_n;
1120  }
1121  }
1122  __catch(...)
1123  {
1124  clear();
1125  if (__buckets)
1126  _M_deallocate_buckets();
1127  __throw_exception_again;
1128  }
1129  }
1130 
1131  template<typename _Key, typename _Value,
1132  typename _Alloc, typename _ExtractKey, typename _Equal,
1133  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1134  typename _Traits>
1135  void
1136  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1137  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1138  _M_reset() noexcept
1139  {
1140  _M_rehash_policy._M_reset();
1141  _M_bucket_count = 1;
1142  _M_single_bucket = nullptr;
1143  _M_buckets = &_M_single_bucket;
1144  _M_before_begin._M_nxt = nullptr;
1145  _M_element_count = 0;
1146  }
1147 
1148  template<typename _Key, typename _Value,
1149  typename _Alloc, typename _ExtractKey, typename _Equal,
1150  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1151  typename _Traits>
1152  void
1153  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1154  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1155  _M_move_assign(_Hashtable&& __ht, std::true_type)
1156  {
1157  this->_M_deallocate_nodes(_M_begin());
1158  _M_deallocate_buckets();
1159  __hashtable_base::operator=(std::move(__ht));
1160  _M_rehash_policy = __ht._M_rehash_policy;
1161  if (!__ht._M_uses_single_bucket())
1162  _M_buckets = __ht._M_buckets;
1163  else
1164  {
1165  _M_buckets = &_M_single_bucket;
1166  _M_single_bucket = __ht._M_single_bucket;
1167  }
1168  _M_bucket_count = __ht._M_bucket_count;
1169  _M_before_begin._M_nxt = __ht._M_before_begin._M_nxt;
1170  _M_element_count = __ht._M_element_count;
1171  std::__alloc_on_move(this->_M_node_allocator(), __ht._M_node_allocator());
1172 
1173  // Fix buckets containing the _M_before_begin pointers that can't be
1174  // moved.
1175  if (_M_begin())
1176  _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
1177  __ht._M_reset();
1178  }
1179 
1180  template<typename _Key, typename _Value,
1181  typename _Alloc, typename _ExtractKey, typename _Equal,
1182  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1183  typename _Traits>
1184  void
1185  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1186  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1187  _M_move_assign(_Hashtable&& __ht, std::false_type)
1188  {
1189  if (__ht._M_node_allocator() == this->_M_node_allocator())
1190  _M_move_assign(std::move(__ht), std::true_type());
1191  else
1192  {
1193  // Can't move memory, move elements then.
1194  __bucket_type* __former_buckets = nullptr;
1195  size_type __former_bucket_count = _M_bucket_count;
1196  const __rehash_state& __former_state = _M_rehash_policy._M_state();
1197 
1198  if (_M_bucket_count != __ht._M_bucket_count)
1199  {
1200  __former_buckets = _M_buckets;
1201  _M_buckets = _M_allocate_buckets(__ht._M_bucket_count);
1202  _M_bucket_count = __ht._M_bucket_count;
1203  }
1204  else
1205  __builtin_memset(_M_buckets, 0,
1206  _M_bucket_count * sizeof(__bucket_type));
1207 
1208  __try
1209  {
1210  __hashtable_base::operator=(std::move(__ht));
1211  _M_element_count = __ht._M_element_count;
1212  _M_rehash_policy = __ht._M_rehash_policy;
1213  __reuse_or_alloc_node_type __roan(_M_begin(), *this);
1214  _M_before_begin._M_nxt = nullptr;
1215  _M_assign(__ht,
1216  [&__roan](__node_type* __n)
1217  { return __roan(std::move_if_noexcept(__n->_M_v())); });
1218  __ht.clear();
1219  }
1220  __catch(...)
1221  {
1222  if (__former_buckets)
1223  {
1224  _M_deallocate_buckets();
1225  _M_rehash_policy._M_reset(__former_state);
1226  _M_buckets = __former_buckets;
1227  _M_bucket_count = __former_bucket_count;
1228  }
1229  __builtin_memset(_M_buckets, 0,
1230  _M_bucket_count * sizeof(__bucket_type));
1231  __throw_exception_again;
1232  }
1233  }
1234  }
1235 
1236  template<typename _Key, typename _Value,
1237  typename _Alloc, typename _ExtractKey, typename _Equal,
1238  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1239  typename _Traits>
1240  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1241  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1242  _Hashtable(const _Hashtable& __ht)
1243  : __hashtable_base(__ht),
1244  __map_base(__ht),
1245  __rehash_base(__ht),
1247  __node_alloc_traits::_S_select_on_copy(__ht._M_node_allocator())),
1248  _M_buckets(nullptr),
1249  _M_bucket_count(__ht._M_bucket_count),
1250  _M_element_count(__ht._M_element_count),
1251  _M_rehash_policy(__ht._M_rehash_policy)
1252  {
1253  _M_assign(__ht,
1254  [this](const __node_type* __n)
1255  { return this->_M_allocate_node(__n->_M_v()); });
1256  }
1257 
1258  template<typename _Key, typename _Value,
1259  typename _Alloc, typename _ExtractKey, typename _Equal,
1260  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1261  typename _Traits>
1262  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1263  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1264  _Hashtable(_Hashtable&& __ht) noexcept
1265  : __hashtable_base(__ht),
1266  __map_base(__ht),
1267  __rehash_base(__ht),
1268  __hashtable_alloc(std::move(__ht._M_base_alloc())),
1269  _M_buckets(__ht._M_buckets),
1270  _M_bucket_count(__ht._M_bucket_count),
1271  _M_before_begin(__ht._M_before_begin._M_nxt),
1272  _M_element_count(__ht._M_element_count),
1273  _M_rehash_policy(__ht._M_rehash_policy)
1274  {
1275  // Update, if necessary, buckets if __ht is using its single bucket.
1276  if (__ht._M_uses_single_bucket())
1277  {
1278  _M_buckets = &_M_single_bucket;
1279  _M_single_bucket = __ht._M_single_bucket;
1280  }
1281 
1282  // Update, if necessary, bucket pointing to before begin that hasn't
1283  // moved.
1284  if (_M_begin())
1285  _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
1286 
1287  __ht._M_reset();
1288  }
1289 
1290  template<typename _Key, typename _Value,
1291  typename _Alloc, typename _ExtractKey, typename _Equal,
1292  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1293  typename _Traits>
1294  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1295  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1296  _Hashtable(const _Hashtable& __ht, const allocator_type& __a)
1297  : __hashtable_base(__ht),
1298  __map_base(__ht),
1299  __rehash_base(__ht),
1300  __hashtable_alloc(__node_alloc_type(__a)),
1301  _M_buckets(),
1302  _M_bucket_count(__ht._M_bucket_count),
1303  _M_element_count(__ht._M_element_count),
1304  _M_rehash_policy(__ht._M_rehash_policy)
1305  {
1306  _M_assign(__ht,
1307  [this](const __node_type* __n)
1308  { return this->_M_allocate_node(__n->_M_v()); });
1309  }
1310 
1311  template<typename _Key, typename _Value,
1312  typename _Alloc, typename _ExtractKey, typename _Equal,
1313  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1314  typename _Traits>
1315  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1316  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1317  _Hashtable(_Hashtable&& __ht, const allocator_type& __a)
1318  : __hashtable_base(__ht),
1319  __map_base(__ht),
1320  __rehash_base(__ht),
1321  __hashtable_alloc(__node_alloc_type(__a)),
1322  _M_buckets(nullptr),
1323  _M_bucket_count(__ht._M_bucket_count),
1324  _M_element_count(__ht._M_element_count),
1325  _M_rehash_policy(__ht._M_rehash_policy)
1326  {
1327  if (__ht._M_node_allocator() == this->_M_node_allocator())
1328  {
1329  if (__ht._M_uses_single_bucket())
1330  {
1331  _M_buckets = &_M_single_bucket;
1332  _M_single_bucket = __ht._M_single_bucket;
1333  }
1334  else
1335  _M_buckets = __ht._M_buckets;
1336 
1337  _M_before_begin._M_nxt = __ht._M_before_begin._M_nxt;
1338  // Update, if necessary, bucket pointing to before begin that hasn't
1339  // moved.
1340  if (_M_begin())
1341  _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
1342  __ht._M_reset();
1343  }
1344  else
1345  {
1346  _M_assign(__ht,
1347  [this](__node_type* __n)
1348  {
1349  return this->_M_allocate_node(
1350  std::move_if_noexcept(__n->_M_v()));
1351  });
1352  __ht.clear();
1353  }
1354  }
1355 
1356  template<typename _Key, typename _Value,
1357  typename _Alloc, typename _ExtractKey, typename _Equal,
1358  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1359  typename _Traits>
1360  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1361  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1362  ~_Hashtable() noexcept
1363  {
1364  clear();
1365  _M_deallocate_buckets();
1366  }
1367 
1368  template<typename _Key, typename _Value,
1369  typename _Alloc, typename _ExtractKey, typename _Equal,
1370  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1371  typename _Traits>
1372  void
1373  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1374  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1375  swap(_Hashtable& __x)
1376  noexcept(__and_<__is_nothrow_swappable<_H1>,
1377  __is_nothrow_swappable<_Equal>>::value)
1378  {
1379  // The only base class with member variables is hash_code_base.
1380  // We define _Hash_code_base::_M_swap because different
1381  // specializations have different members.
1382  this->_M_swap(__x);
1383 
1384  std::__alloc_on_swap(this->_M_node_allocator(), __x._M_node_allocator());
1385  std::swap(_M_rehash_policy, __x._M_rehash_policy);
1386 
1387  // Deal properly with potentially moved instances.
1388  if (this->_M_uses_single_bucket())
1389  {
1390  if (!__x._M_uses_single_bucket())
1391  {
1392  _M_buckets = __x._M_buckets;
1393  __x._M_buckets = &__x._M_single_bucket;
1394  }
1395  }
1396  else if (__x._M_uses_single_bucket())
1397  {
1398  __x._M_buckets = _M_buckets;
1399  _M_buckets = &_M_single_bucket;
1400  }
1401  else
1402  std::swap(_M_buckets, __x._M_buckets);
1403 
1404  std::swap(_M_bucket_count, __x._M_bucket_count);
1405  std::swap(_M_before_begin._M_nxt, __x._M_before_begin._M_nxt);
1406  std::swap(_M_element_count, __x._M_element_count);
1407  std::swap(_M_single_bucket, __x._M_single_bucket);
1408 
1409  // Fix buckets containing the _M_before_begin pointers that can't be
1410  // swapped.
1411  if (_M_begin())
1412  _M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
1413 
1414  if (__x._M_begin())
1415  __x._M_buckets[__x._M_bucket_index(__x._M_begin())]
1416  = &__x._M_before_begin;
1417  }
1418 
1419  template<typename _Key, typename _Value,
1420  typename _Alloc, typename _ExtractKey, typename _Equal,
1421  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1422  typename _Traits>
1423  auto
1424  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1425  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1426  find(const key_type& __k)
1427  -> iterator
1428  {
1429  __hash_code __code = this->_M_hash_code(__k);
1430  std::size_t __n = _M_bucket_index(__k, __code);
1431  __node_type* __p = _M_find_node(__n, __k, __code);
1432  return __p ? iterator(__p) : end();
1433  }
1434 
1435  template<typename _Key, typename _Value,
1436  typename _Alloc, typename _ExtractKey, typename _Equal,
1437  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1438  typename _Traits>
1439  auto
1440  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1441  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1442  find(const key_type& __k) const
1443  -> const_iterator
1444  {
1445  __hash_code __code = this->_M_hash_code(__k);
1446  std::size_t __n = _M_bucket_index(__k, __code);
1447  __node_type* __p = _M_find_node(__n, __k, __code);
1448  return __p ? const_iterator(__p) : end();
1449  }
1450 
1451  template<typename _Key, typename _Value,
1452  typename _Alloc, typename _ExtractKey, typename _Equal,
1453  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1454  typename _Traits>
1455  auto
1456  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1457  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1458  count(const key_type& __k) const
1459  -> size_type
1460  {
1461  __hash_code __code = this->_M_hash_code(__k);
1462  std::size_t __n = _M_bucket_index(__k, __code);
1463  __node_type* __p = _M_bucket_begin(__n);
1464  if (!__p)
1465  return 0;
1466 
1467  std::size_t __result = 0;
1468  for (;; __p = __p->_M_next())
1469  {
1470  if (this->_M_equals(__k, __code, __p))
1471  ++__result;
1472  else if (__result)
1473  // All equivalent values are next to each other, if we
1474  // found a non-equivalent value after an equivalent one it
1475  // means that we won't find any new equivalent value.
1476  break;
1477  if (!__p->_M_nxt || _M_bucket_index(__p->_M_next()) != __n)
1478  break;
1479  }
1480  return __result;
1481  }
1482 
1483  template<typename _Key, typename _Value,
1484  typename _Alloc, typename _ExtractKey, typename _Equal,
1485  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1486  typename _Traits>
1487  auto
1488  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1489  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1490  equal_range(const key_type& __k)
1492  {
1493  __hash_code __code = this->_M_hash_code(__k);
1494  std::size_t __n = _M_bucket_index(__k, __code);
1495  __node_type* __p = _M_find_node(__n, __k, __code);
1496 
1497  if (__p)
1498  {
1499  __node_type* __p1 = __p->_M_next();
1500  while (__p1 && _M_bucket_index(__p1) == __n
1501  && this->_M_equals(__k, __code, __p1))
1502  __p1 = __p1->_M_next();
1503 
1504  return std::make_pair(iterator(__p), iterator(__p1));
1505  }
1506  else
1507  return std::make_pair(end(), end());
1508  }
1509 
1510  template<typename _Key, typename _Value,
1511  typename _Alloc, typename _ExtractKey, typename _Equal,
1512  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1513  typename _Traits>
1514  auto
1515  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1516  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1517  equal_range(const key_type& __k) const
1519  {
1520  __hash_code __code = this->_M_hash_code(__k);
1521  std::size_t __n = _M_bucket_index(__k, __code);
1522  __node_type* __p = _M_find_node(__n, __k, __code);
1523 
1524  if (__p)
1525  {
1526  __node_type* __p1 = __p->_M_next();
1527  while (__p1 && _M_bucket_index(__p1) == __n
1528  && this->_M_equals(__k, __code, __p1))
1529  __p1 = __p1->_M_next();
1530 
1531  return std::make_pair(const_iterator(__p), const_iterator(__p1));
1532  }
1533  else
1534  return std::make_pair(end(), end());
1535  }
1536 
1537  // Find the node whose key compares equal to k in the bucket n.
1538  // Return nullptr if no node is found.
1539  template<typename _Key, typename _Value,
1540  typename _Alloc, typename _ExtractKey, typename _Equal,
1541  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1542  typename _Traits>
1543  auto
1544  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1545  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1546  _M_find_before_node(size_type __n, const key_type& __k,
1547  __hash_code __code) const
1548  -> __node_base*
1549  {
1550  __node_base* __prev_p = _M_buckets[__n];
1551  if (!__prev_p)
1552  return nullptr;
1553 
1554  for (__node_type* __p = static_cast<__node_type*>(__prev_p->_M_nxt);;
1555  __p = __p->_M_next())
1556  {
1557  if (this->_M_equals(__k, __code, __p))
1558  return __prev_p;
1559 
1560  if (!__p->_M_nxt || _M_bucket_index(__p->_M_next()) != __n)
1561  break;
1562  __prev_p = __p;
1563  }
1564  return nullptr;
1565  }
1566 
1567  template<typename _Key, typename _Value,
1568  typename _Alloc, typename _ExtractKey, typename _Equal,
1569  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1570  typename _Traits>
1571  void
1572  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1573  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1574  _M_insert_bucket_begin(size_type __bkt, __node_type* __node)
1575  {
1576  if (_M_buckets[__bkt])
1577  {
1578  // Bucket is not empty, we just need to insert the new node
1579  // after the bucket before begin.
1580  __node->_M_nxt = _M_buckets[__bkt]->_M_nxt;
1581  _M_buckets[__bkt]->_M_nxt = __node;
1582  }
1583  else
1584  {
1585  // The bucket is empty, the new node is inserted at the
1586  // beginning of the singly-linked list and the bucket will
1587  // contain _M_before_begin pointer.
1588  __node->_M_nxt = _M_before_begin._M_nxt;
1589  _M_before_begin._M_nxt = __node;
1590  if (__node->_M_nxt)
1591  // We must update former begin bucket that is pointing to
1592  // _M_before_begin.
1593  _M_buckets[_M_bucket_index(__node->_M_next())] = __node;
1594  _M_buckets[__bkt] = &_M_before_begin;
1595  }
1596  }
1597 
1598  template<typename _Key, typename _Value,
1599  typename _Alloc, typename _ExtractKey, typename _Equal,
1600  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1601  typename _Traits>
1602  void
1603  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1604  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1605  _M_remove_bucket_begin(size_type __bkt, __node_type* __next,
1606  size_type __next_bkt)
1607  {
1608  if (!__next || __next_bkt != __bkt)
1609  {
1610  // Bucket is now empty
1611  // First update next bucket if any
1612  if (__next)
1613  _M_buckets[__next_bkt] = _M_buckets[__bkt];
1614 
1615  // Second update before begin node if necessary
1616  if (&_M_before_begin == _M_buckets[__bkt])
1617  _M_before_begin._M_nxt = __next;
1618  _M_buckets[__bkt] = nullptr;
1619  }
1620  }
1621 
1622  template<typename _Key, typename _Value,
1623  typename _Alloc, typename _ExtractKey, typename _Equal,
1624  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1625  typename _Traits>
1626  auto
1627  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1628  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1629  _M_get_previous_node(size_type __bkt, __node_base* __n)
1630  -> __node_base*
1631  {
1632  __node_base* __prev_n = _M_buckets[__bkt];
1633  while (__prev_n->_M_nxt != __n)
1634  __prev_n = __prev_n->_M_nxt;
1635  return __prev_n;
1636  }
1637 
1638  template<typename _Key, typename _Value,
1639  typename _Alloc, typename _ExtractKey, typename _Equal,
1640  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1641  typename _Traits>
1642  template<typename... _Args>
1643  auto
1644  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1645  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1646  _M_emplace(std::true_type, _Args&&... __args)
1648  {
1649  // First build the node to get access to the hash code
1650  __node_type* __node = this->_M_allocate_node(std::forward<_Args>(__args)...);
1651  const key_type& __k = this->_M_extract()(__node->_M_v());
1652  __hash_code __code;
1653  __try
1654  {
1655  __code = this->_M_hash_code(__k);
1656  }
1657  __catch(...)
1658  {
1659  this->_M_deallocate_node(__node);
1660  __throw_exception_again;
1661  }
1662 
1663  size_type __bkt = _M_bucket_index(__k, __code);
1664  if (__node_type* __p = _M_find_node(__bkt, __k, __code))
1665  {
1666  // There is already an equivalent node, no insertion
1667  this->_M_deallocate_node(__node);
1668  return std::make_pair(iterator(__p), false);
1669  }
1670 
1671  // Insert the node
1672  return std::make_pair(_M_insert_unique_node(__bkt, __code, __node),
1673  true);
1674  }
1675 
1676  template<typename _Key, typename _Value,
1677  typename _Alloc, typename _ExtractKey, typename _Equal,
1678  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1679  typename _Traits>
1680  template<typename... _Args>
1681  auto
1682  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1683  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1684  _M_emplace(const_iterator __hint, std::false_type, _Args&&... __args)
1685  -> iterator
1686  {
1687  // First build the node to get its hash code.
1688  __node_type* __node =
1689  this->_M_allocate_node(std::forward<_Args>(__args)...);
1690 
1691  __hash_code __code;
1692  __try
1693  {
1694  __code = this->_M_hash_code(this->_M_extract()(__node->_M_v()));
1695  }
1696  __catch(...)
1697  {
1698  this->_M_deallocate_node(__node);
1699  __throw_exception_again;
1700  }
1701 
1702  return _M_insert_multi_node(__hint._M_cur, __code, __node);
1703  }
1704 
1705  template<typename _Key, typename _Value,
1706  typename _Alloc, typename _ExtractKey, typename _Equal,
1707  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1708  typename _Traits>
1709  auto
1710  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1711  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1712  _M_insert_unique_node(size_type __bkt, __hash_code __code,
1713  __node_type* __node)
1714  -> iterator
1715  {
1716  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
1717  std::pair<bool, std::size_t> __do_rehash
1718  = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count, 1);
1719 
1720  __try
1721  {
1722  if (__do_rehash.first)
1723  {
1724  _M_rehash(__do_rehash.second, __saved_state);
1725  __bkt = _M_bucket_index(this->_M_extract()(__node->_M_v()), __code);
1726  }
1727 
1728  this->_M_store_code(__node, __code);
1729 
1730  // Always insert at the beginning of the bucket.
1731  _M_insert_bucket_begin(__bkt, __node);
1732  ++_M_element_count;
1733  return iterator(__node);
1734  }
1735  __catch(...)
1736  {
1737  this->_M_deallocate_node(__node);
1738  __throw_exception_again;
1739  }
1740  }
1741 
1742  // Insert node, in bucket bkt if no rehash (assumes no element with its key
1743  // already present). Take ownership of the node, deallocate it on exception.
1744  template<typename _Key, typename _Value,
1745  typename _Alloc, typename _ExtractKey, typename _Equal,
1746  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1747  typename _Traits>
1748  auto
1749  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1750  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1751  _M_insert_multi_node(__node_type* __hint, __hash_code __code,
1752  __node_type* __node)
1753  -> iterator
1754  {
1755  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
1756  std::pair<bool, std::size_t> __do_rehash
1757  = _M_rehash_policy._M_need_rehash(_M_bucket_count, _M_element_count, 1);
1758 
1759  __try
1760  {
1761  if (__do_rehash.first)
1762  _M_rehash(__do_rehash.second, __saved_state);
1763 
1764  this->_M_store_code(__node, __code);
1765  const key_type& __k = this->_M_extract()(__node->_M_v());
1766  size_type __bkt = _M_bucket_index(__k, __code);
1767 
1768  // Find the node before an equivalent one or use hint if it exists and
1769  // if it is equivalent.
1770  __node_base* __prev
1771  = __builtin_expect(__hint != nullptr, false)
1772  && this->_M_equals(__k, __code, __hint)
1773  ? __hint
1774  : _M_find_before_node(__bkt, __k, __code);
1775  if (__prev)
1776  {
1777  // Insert after the node before the equivalent one.
1778  __node->_M_nxt = __prev->_M_nxt;
1779  __prev->_M_nxt = __node;
1780  if (__builtin_expect(__prev == __hint, false))
1781  // hint might be the last bucket node, in this case we need to
1782  // update next bucket.
1783  if (__node->_M_nxt
1784  && !this->_M_equals(__k, __code, __node->_M_next()))
1785  {
1786  size_type __next_bkt = _M_bucket_index(__node->_M_next());
1787  if (__next_bkt != __bkt)
1788  _M_buckets[__next_bkt] = __node;
1789  }
1790  }
1791  else
1792  // The inserted node has no equivalent in the
1793  // hashtable. We must insert the new node at the
1794  // beginning of the bucket to preserve equivalent
1795  // elements' relative positions.
1796  _M_insert_bucket_begin(__bkt, __node);
1797  ++_M_element_count;
1798  return iterator(__node);
1799  }
1800  __catch(...)
1801  {
1802  this->_M_deallocate_node(__node);
1803  __throw_exception_again;
1804  }
1805  }
1806 
1807  // Insert v if no element with its key is already present.
1808  template<typename _Key, typename _Value,
1809  typename _Alloc, typename _ExtractKey, typename _Equal,
1810  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1811  typename _Traits>
1812  template<typename _Arg, typename _NodeGenerator>
1813  auto
1814  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1815  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1816  _M_insert(_Arg&& __v, const _NodeGenerator& __node_gen, std::true_type)
1818  {
1819  const key_type& __k = this->_M_extract()(__v);
1820  __hash_code __code = this->_M_hash_code(__k);
1821  size_type __bkt = _M_bucket_index(__k, __code);
1822 
1823  __node_type* __n = _M_find_node(__bkt, __k, __code);
1824  if (__n)
1825  return std::make_pair(iterator(__n), false);
1826 
1827  __n = __node_gen(std::forward<_Arg>(__v));
1828  return std::make_pair(_M_insert_unique_node(__bkt, __code, __n), true);
1829  }
1830 
1831  // Insert v unconditionally.
1832  template<typename _Key, typename _Value,
1833  typename _Alloc, typename _ExtractKey, typename _Equal,
1834  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1835  typename _Traits>
1836  template<typename _Arg, typename _NodeGenerator>
1837  auto
1838  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1839  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1840  _M_insert(const_iterator __hint, _Arg&& __v,
1841  const _NodeGenerator& __node_gen, std::false_type)
1842  -> iterator
1843  {
1844  // First compute the hash code so that we don't do anything if it
1845  // throws.
1846  __hash_code __code = this->_M_hash_code(this->_M_extract()(__v));
1847 
1848  // Second allocate new node so that we don't rehash if it throws.
1849  __node_type* __node = __node_gen(std::forward<_Arg>(__v));
1850 
1851  return _M_insert_multi_node(__hint._M_cur, __code, __node);
1852  }
1853 
1854  template<typename _Key, typename _Value,
1855  typename _Alloc, typename _ExtractKey, typename _Equal,
1856  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1857  typename _Traits>
1858  auto
1859  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1860  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1861  erase(const_iterator __it)
1862  -> iterator
1863  {
1864  __node_type* __n = __it._M_cur;
1865  std::size_t __bkt = _M_bucket_index(__n);
1866 
1867  // Look for previous node to unlink it from the erased one, this
1868  // is why we need buckets to contain the before begin to make
1869  // this search fast.
1870  __node_base* __prev_n = _M_get_previous_node(__bkt, __n);
1871  return _M_erase(__bkt, __prev_n, __n);
1872  }
1873 
1874  template<typename _Key, typename _Value,
1875  typename _Alloc, typename _ExtractKey, typename _Equal,
1876  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1877  typename _Traits>
1878  auto
1879  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1880  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1881  _M_erase(size_type __bkt, __node_base* __prev_n, __node_type* __n)
1882  -> iterator
1883  {
1884  if (__prev_n == _M_buckets[__bkt])
1885  _M_remove_bucket_begin(__bkt, __n->_M_next(),
1886  __n->_M_nxt ? _M_bucket_index(__n->_M_next()) : 0);
1887  else if (__n->_M_nxt)
1888  {
1889  size_type __next_bkt = _M_bucket_index(__n->_M_next());
1890  if (__next_bkt != __bkt)
1891  _M_buckets[__next_bkt] = __prev_n;
1892  }
1893 
1894  __prev_n->_M_nxt = __n->_M_nxt;
1895  iterator __result(__n->_M_next());
1896  this->_M_deallocate_node(__n);
1897  --_M_element_count;
1898 
1899  return __result;
1900  }
1901 
1902  template<typename _Key, typename _Value,
1903  typename _Alloc, typename _ExtractKey, typename _Equal,
1904  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1905  typename _Traits>
1906  auto
1907  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1908  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1909  _M_erase(std::true_type, const key_type& __k)
1910  -> size_type
1911  {
1912  __hash_code __code = this->_M_hash_code(__k);
1913  std::size_t __bkt = _M_bucket_index(__k, __code);
1914 
1915  // Look for the node before the first matching node.
1916  __node_base* __prev_n = _M_find_before_node(__bkt, __k, __code);
1917  if (!__prev_n)
1918  return 0;
1919 
1920  // We found a matching node, erase it.
1921  __node_type* __n = static_cast<__node_type*>(__prev_n->_M_nxt);
1922  _M_erase(__bkt, __prev_n, __n);
1923  return 1;
1924  }
1925 
1926  template<typename _Key, typename _Value,
1927  typename _Alloc, typename _ExtractKey, typename _Equal,
1928  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1929  typename _Traits>
1930  auto
1931  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1932  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1933  _M_erase(std::false_type, const key_type& __k)
1934  -> size_type
1935  {
1936  __hash_code __code = this->_M_hash_code(__k);
1937  std::size_t __bkt = _M_bucket_index(__k, __code);
1938 
1939  // Look for the node before the first matching node.
1940  __node_base* __prev_n = _M_find_before_node(__bkt, __k, __code);
1941  if (!__prev_n)
1942  return 0;
1943 
1944  // _GLIBCXX_RESOLVE_LIB_DEFECTS
1945  // 526. Is it undefined if a function in the standard changes
1946  // in parameters?
1947  // We use one loop to find all matching nodes and another to deallocate
1948  // them so that the key stays valid during the first loop. It might be
1949  // invalidated indirectly when destroying nodes.
1950  __node_type* __n = static_cast<__node_type*>(__prev_n->_M_nxt);
1951  __node_type* __n_last = __n;
1952  std::size_t __n_last_bkt = __bkt;
1953  do
1954  {
1955  __n_last = __n_last->_M_next();
1956  if (!__n_last)
1957  break;
1958  __n_last_bkt = _M_bucket_index(__n_last);
1959  }
1960  while (__n_last_bkt == __bkt && this->_M_equals(__k, __code, __n_last));
1961 
1962  // Deallocate nodes.
1963  size_type __result = 0;
1964  do
1965  {
1966  __node_type* __p = __n->_M_next();
1967  this->_M_deallocate_node(__n);
1968  __n = __p;
1969  ++__result;
1970  --_M_element_count;
1971  }
1972  while (__n != __n_last);
1973 
1974  if (__prev_n == _M_buckets[__bkt])
1975  _M_remove_bucket_begin(__bkt, __n_last, __n_last_bkt);
1976  else if (__n_last && __n_last_bkt != __bkt)
1977  _M_buckets[__n_last_bkt] = __prev_n;
1978  __prev_n->_M_nxt = __n_last;
1979  return __result;
1980  }
1981 
1982  template<typename _Key, typename _Value,
1983  typename _Alloc, typename _ExtractKey, typename _Equal,
1984  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
1985  typename _Traits>
1986  auto
1987  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1988  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
1989  erase(const_iterator __first, const_iterator __last)
1990  -> iterator
1991  {
1992  __node_type* __n = __first._M_cur;
1993  __node_type* __last_n = __last._M_cur;
1994  if (__n == __last_n)
1995  return iterator(__n);
1996 
1997  std::size_t __bkt = _M_bucket_index(__n);
1998 
1999  __node_base* __prev_n = _M_get_previous_node(__bkt, __n);
2000  bool __is_bucket_begin = __n == _M_bucket_begin(__bkt);
2001  std::size_t __n_bkt = __bkt;
2002  for (;;)
2003  {
2004  do
2005  {
2006  __node_type* __tmp = __n;
2007  __n = __n->_M_next();
2008  this->_M_deallocate_node(__tmp);
2009  --_M_element_count;
2010  if (!__n)
2011  break;
2012  __n_bkt = _M_bucket_index(__n);
2013  }
2014  while (__n != __last_n && __n_bkt == __bkt);
2015  if (__is_bucket_begin)
2016  _M_remove_bucket_begin(__bkt, __n, __n_bkt);
2017  if (__n == __last_n)
2018  break;
2019  __is_bucket_begin = true;
2020  __bkt = __n_bkt;
2021  }
2022 
2023  if (__n && (__n_bkt != __bkt || __is_bucket_begin))
2024  _M_buckets[__n_bkt] = __prev_n;
2025  __prev_n->_M_nxt = __n;
2026  return iterator(__n);
2027  }
2028 
2029  template<typename _Key, typename _Value,
2030  typename _Alloc, typename _ExtractKey, typename _Equal,
2031  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
2032  typename _Traits>
2033  void
2034  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2035  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
2036  clear() noexcept
2037  {
2038  this->_M_deallocate_nodes(_M_begin());
2039  __builtin_memset(_M_buckets, 0, _M_bucket_count * sizeof(__bucket_type));
2040  _M_element_count = 0;
2041  _M_before_begin._M_nxt = nullptr;
2042  }
2043 
2044  template<typename _Key, typename _Value,
2045  typename _Alloc, typename _ExtractKey, typename _Equal,
2046  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
2047  typename _Traits>
2048  void
2049  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2050  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
2051  rehash(size_type __n)
2052  {
2053  const __rehash_state& __saved_state = _M_rehash_policy._M_state();
2054  std::size_t __buckets
2055  = std::max(_M_rehash_policy._M_bkt_for_elements(_M_element_count + 1),
2056  __n);
2057  __buckets = _M_rehash_policy._M_next_bkt(__buckets);
2058 
2059  if (__buckets != _M_bucket_count)
2060  _M_rehash(__buckets, __saved_state);
2061  else
2062  // No rehash, restore previous state to keep a consistent state.
2063  _M_rehash_policy._M_reset(__saved_state);
2064  }
2065 
2066  template<typename _Key, typename _Value,
2067  typename _Alloc, typename _ExtractKey, typename _Equal,
2068  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
2069  typename _Traits>
2070  void
2071  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2072  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
2073  _M_rehash(size_type __n, const __rehash_state& __state)
2074  {
2075  __try
2076  {
2077  _M_rehash_aux(__n, __unique_keys());
2078  }
2079  __catch(...)
2080  {
2081  // A failure here means that buckets allocation failed. We only
2082  // have to restore hash policy previous state.
2083  _M_rehash_policy._M_reset(__state);
2084  __throw_exception_again;
2085  }
2086  }
2087 
2088  // Rehash when there is no equivalent elements.
2089  template<typename _Key, typename _Value,
2090  typename _Alloc, typename _ExtractKey, typename _Equal,
2091  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
2092  typename _Traits>
2093  void
2094  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2095  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
2096  _M_rehash_aux(size_type __n, std::true_type)
2097  {
2098  __bucket_type* __new_buckets = _M_allocate_buckets(__n);
2099  __node_type* __p = _M_begin();
2100  _M_before_begin._M_nxt = nullptr;
2101  std::size_t __bbegin_bkt = 0;
2102  while (__p)
2103  {
2104  __node_type* __next = __p->_M_next();
2105  std::size_t __bkt = __hash_code_base::_M_bucket_index(__p, __n);
2106  if (!__new_buckets[__bkt])
2107  {
2108  __p->_M_nxt = _M_before_begin._M_nxt;
2109  _M_before_begin._M_nxt = __p;
2110  __new_buckets[__bkt] = &_M_before_begin;
2111  if (__p->_M_nxt)
2112  __new_buckets[__bbegin_bkt] = __p;
2113  __bbegin_bkt = __bkt;
2114  }
2115  else
2116  {
2117  __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
2118  __new_buckets[__bkt]->_M_nxt = __p;
2119  }
2120  __p = __next;
2121  }
2122 
2123  _M_deallocate_buckets();
2124  _M_bucket_count = __n;
2125  _M_buckets = __new_buckets;
2126  }
2127 
2128  // Rehash when there can be equivalent elements, preserve their relative
2129  // order.
2130  template<typename _Key, typename _Value,
2131  typename _Alloc, typename _ExtractKey, typename _Equal,
2132  typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
2133  typename _Traits>
2134  void
2135  _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
2136  _H1, _H2, _Hash, _RehashPolicy, _Traits>::
2137  _M_rehash_aux(size_type __n, std::false_type)
2138  {
2139  __bucket_type* __new_buckets = _M_allocate_buckets(__n);
2140 
2141  __node_type* __p = _M_begin();
2142  _M_before_begin._M_nxt = nullptr;
2143  std::size_t __bbegin_bkt = 0;
2144  std::size_t __prev_bkt = 0;
2145  __node_type* __prev_p = nullptr;
2146  bool __check_bucket = false;
2147 
2148  while (__p)
2149  {
2150  __node_type* __next = __p->_M_next();
2151  std::size_t __bkt = __hash_code_base::_M_bucket_index(__p, __n);
2152 
2153  if (__prev_p && __prev_bkt == __bkt)
2154  {
2155  // Previous insert was already in this bucket, we insert after
2156  // the previously inserted one to preserve equivalent elements
2157  // relative order.
2158  __p->_M_nxt = __prev_p->_M_nxt;
2159  __prev_p->_M_nxt = __p;
2160 
2161  // Inserting after a node in a bucket require to check that we
2162  // haven't change the bucket last node, in this case next
2163  // bucket containing its before begin node must be updated. We
2164  // schedule a check as soon as we move out of the sequence of
2165  // equivalent nodes to limit the number of checks.
2166  __check_bucket = true;
2167  }
2168  else
2169  {
2170  if (__check_bucket)
2171  {
2172  // Check if we shall update the next bucket because of
2173  // insertions into __prev_bkt bucket.
2174  if (__prev_p->_M_nxt)
2175  {
2176  std::size_t __next_bkt
2177  = __hash_code_base::_M_bucket_index(__prev_p->_M_next(),
2178  __n);
2179  if (__next_bkt != __prev_bkt)
2180  __new_buckets[__next_bkt] = __prev_p;
2181  }
2182  __check_bucket = false;
2183  }
2184 
2185  if (!__new_buckets[__bkt])
2186  {
2187  __p->_M_nxt = _M_before_begin._M_nxt;
2188  _M_before_begin._M_nxt = __p;
2189  __new_buckets[__bkt] = &_M_before_begin;
2190  if (__p->_M_nxt)
2191  __new_buckets[__bbegin_bkt] = __p;
2192  __bbegin_bkt = __bkt;
2193  }
2194  else
2195  {
2196  __p->_M_nxt = __new_buckets[__bkt]->_M_nxt;
2197  __new_buckets[__bkt]->_M_nxt = __p;
2198  }
2199  }
2200  __prev_p = __p;
2201  __prev_bkt = __bkt;
2202  __p = __next;
2203  }
2204 
2205  if (__check_bucket && __prev_p->_M_nxt)
2206  {
2207  std::size_t __next_bkt
2208  = __hash_code_base::_M_bucket_index(__prev_p->_M_next(), __n);
2209  if (__next_bkt != __prev_bkt)
2210  __new_buckets[__next_bkt] = __prev_p;
2211  }
2212 
2213  _M_deallocate_buckets();
2214  _M_bucket_count = __n;
2215  _M_buckets = __new_buckets;
2216  }
2217 
2218 #if __cplusplus > 201402L
2219  template<typename, typename, typename> class _Hash_merge_helper { };
2220 #endif // C++17
2221 
2222 _GLIBCXX_END_NAMESPACE_VERSION
2223 } // namespace std
2224 
2225 #endif // _HASHTABLE_H
_T2 second
first is a copy of the first object
Definition: stl_pair.h:204
_Tp exchange(_Tp &__obj, _Up &&__new_val)
Assign __new_val to __obj and return its previous value.
Definition: utility:260
Uniform interface to C++98 and C++11 allocators.
constexpr const _Tp * begin(initializer_list< _Tp > __ils) noexcept
Return an iterator pointing to the first element of the initializer_list.
Node iterators, used to iterate through all the hashtable.
initializer_list
_T1 first
second_type is the second bound type
Definition: stl_pair.h:203
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:87
integral_constant
Definition: type_traits:69
constexpr const _Tp * end(initializer_list< _Tp > __ils) noexcept
Return an iterator pointing to one past the last element of the initializer_list. ...
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
ISO C++ entities toplevel namespace is std.
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:519
Node const_iterators, used to iterate through all the hashtable.
_GLIBCXX17_CONSTEXPR iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
Struct holding two objects of arbitrary type.
Definition: stl_pair.h:198
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:118
Uniform interface to all allocator types.
_GLIBCXX14_CONSTEXPR const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:219
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