libstdc++
hashtable_policy.h
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1 // Internal policy header for unordered_set and unordered_map -*- C++ -*-
2 
3 // Copyright (C) 2010-2023 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file bits/hashtable_policy.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly.
28  * @headername{unordered_map,unordered_set}
29  */
30 
31 #ifndef _HASHTABLE_POLICY_H
32 #define _HASHTABLE_POLICY_H 1
33 
34 #include <tuple> // for std::tuple, std::forward_as_tuple
35 #include <bits/functional_hash.h> // for __is_fast_hash
36 #include <bits/stl_algobase.h> // for std::min, std::is_permutation.
37 #include <bits/stl_pair.h> // for std::pair
38 #include <ext/aligned_buffer.h> // for __gnu_cxx::__aligned_buffer
39 #include <ext/alloc_traits.h> // for std::__alloc_rebind
40 #include <ext/numeric_traits.h> // for __gnu_cxx::__int_traits
41 
42 namespace std _GLIBCXX_VISIBILITY(default)
43 {
44 _GLIBCXX_BEGIN_NAMESPACE_VERSION
45 /// @cond undocumented
46 
47  template<typename _Key, typename _Value, typename _Alloc,
48  typename _ExtractKey, typename _Equal,
49  typename _Hash, typename _RangeHash, typename _Unused,
50  typename _RehashPolicy, typename _Traits>
51  class _Hashtable;
52 
53 namespace __detail
54 {
55  /**
56  * @defgroup hashtable-detail Base and Implementation Classes
57  * @ingroup unordered_associative_containers
58  * @{
59  */
60  template<typename _Key, typename _Value, typename _ExtractKey,
61  typename _Equal, typename _Hash, typename _RangeHash,
62  typename _Unused, typename _Traits>
63  struct _Hashtable_base;
64 
65  // Helper function: return distance(first, last) for forward
66  // iterators, or 0/1 for input iterators.
67  template<typename _Iterator>
69  __distance_fw(_Iterator __first, _Iterator __last,
71  { return __first != __last ? 1 : 0; }
72 
73  template<typename _Iterator>
75  __distance_fw(_Iterator __first, _Iterator __last,
77  { return std::distance(__first, __last); }
78 
79  template<typename _Iterator>
81  __distance_fw(_Iterator __first, _Iterator __last)
82  { return __distance_fw(__first, __last,
83  std::__iterator_category(__first)); }
84 
85  struct _Identity
86  {
87  template<typename _Tp>
88  _Tp&&
89  operator()(_Tp&& __x) const noexcept
90  { return std::forward<_Tp>(__x); }
91  };
92 
93  struct _Select1st
94  {
95  template<typename _Pair>
96  struct __1st_type;
97 
98  template<typename _Tp, typename _Up>
99  struct __1st_type<pair<_Tp, _Up>>
100  { using type = _Tp; };
101 
102  template<typename _Tp, typename _Up>
103  struct __1st_type<const pair<_Tp, _Up>>
104  { using type = const _Tp; };
105 
106  template<typename _Pair>
107  struct __1st_type<_Pair&>
108  { using type = typename __1st_type<_Pair>::type&; };
109 
110  template<typename _Tp>
111  typename __1st_type<_Tp>::type&&
112  operator()(_Tp&& __x) const noexcept
113  { return std::forward<_Tp>(__x).first; }
114  };
115 
116  template<typename _ExKey, typename _Value>
117  struct _ConvertToValueType;
118 
119  template<typename _Value>
120  struct _ConvertToValueType<_Identity, _Value>
121  {
122  template<typename _Kt>
123  constexpr _Kt&&
124  operator()(_Kt&& __k) const noexcept
125  { return std::forward<_Kt>(__k); }
126  };
127 
128  template<typename _Value>
129  struct _ConvertToValueType<_Select1st, _Value>
130  {
131  constexpr _Value&&
132  operator()(_Value&& __x) const noexcept
133  { return std::move(__x); }
134 
135  constexpr const _Value&
136  operator()(const _Value& __x) const noexcept
137  { return __x; }
138 
139  template<typename _Kt, typename _Val>
140  constexpr std::pair<_Kt, _Val>&&
141  operator()(std::pair<_Kt, _Val>&& __x) const noexcept
142  { return std::move(__x); }
143 
144  template<typename _Kt, typename _Val>
145  constexpr const std::pair<_Kt, _Val>&
146  operator()(const std::pair<_Kt, _Val>& __x) const noexcept
147  { return __x; }
148  };
149 
150  template<typename _ExKey>
151  struct _NodeBuilder;
152 
153  template<>
154  struct _NodeBuilder<_Select1st>
155  {
156  template<typename _Kt, typename _Arg, typename _NodeGenerator>
157  static auto
158  _S_build(_Kt&& __k, _Arg&& __arg, const _NodeGenerator& __node_gen)
159  -> typename _NodeGenerator::__node_type*
160  {
161  return __node_gen(std::forward<_Kt>(__k),
162  std::forward<_Arg>(__arg).second);
163  }
164  };
165 
166  template<>
167  struct _NodeBuilder<_Identity>
168  {
169  template<typename _Kt, typename _Arg, typename _NodeGenerator>
170  static auto
171  _S_build(_Kt&& __k, _Arg&&, const _NodeGenerator& __node_gen)
172  -> typename _NodeGenerator::__node_type*
173  { return __node_gen(std::forward<_Kt>(__k)); }
174  };
175 
176  template<typename _NodeAlloc>
177  struct _Hashtable_alloc;
178 
179  // Functor recycling a pool of nodes and using allocation once the pool is
180  // empty.
181  template<typename _NodeAlloc>
182  struct _ReuseOrAllocNode
183  {
184  private:
185  using __node_alloc_type = _NodeAlloc;
186  using __hashtable_alloc = _Hashtable_alloc<__node_alloc_type>;
187  using __node_alloc_traits =
188  typename __hashtable_alloc::__node_alloc_traits;
189 
190  public:
191  using __node_type = typename __hashtable_alloc::__node_type;
192 
193  _ReuseOrAllocNode(__node_type* __nodes, __hashtable_alloc& __h)
194  : _M_nodes(__nodes), _M_h(__h) { }
195  _ReuseOrAllocNode(const _ReuseOrAllocNode&) = delete;
196 
197  ~_ReuseOrAllocNode()
198  { _M_h._M_deallocate_nodes(_M_nodes); }
199 
200  template<typename... _Args>
201  __node_type*
202  operator()(_Args&&... __args) const
203  {
204  if (_M_nodes)
205  {
206  __node_type* __node = _M_nodes;
207  _M_nodes = _M_nodes->_M_next();
208  __node->_M_nxt = nullptr;
209  auto& __a = _M_h._M_node_allocator();
210  __node_alloc_traits::destroy(__a, __node->_M_valptr());
211  __try
212  {
213  __node_alloc_traits::construct(__a, __node->_M_valptr(),
214  std::forward<_Args>(__args)...);
215  }
216  __catch(...)
217  {
218  _M_h._M_deallocate_node_ptr(__node);
219  __throw_exception_again;
220  }
221  return __node;
222  }
223  return _M_h._M_allocate_node(std::forward<_Args>(__args)...);
224  }
225 
226  private:
227  mutable __node_type* _M_nodes;
228  __hashtable_alloc& _M_h;
229  };
230 
231  // Functor similar to the previous one but without any pool of nodes to
232  // recycle.
233  template<typename _NodeAlloc>
234  struct _AllocNode
235  {
236  private:
237  using __hashtable_alloc = _Hashtable_alloc<_NodeAlloc>;
238 
239  public:
240  using __node_type = typename __hashtable_alloc::__node_type;
241 
242  _AllocNode(__hashtable_alloc& __h)
243  : _M_h(__h) { }
244 
245  template<typename... _Args>
246  __node_type*
247  operator()(_Args&&... __args) const
248  { return _M_h._M_allocate_node(std::forward<_Args>(__args)...); }
249 
250  private:
251  __hashtable_alloc& _M_h;
252  };
253 
254  // Auxiliary types used for all instantiations of _Hashtable nodes
255  // and iterators.
256 
257  /**
258  * struct _Hashtable_traits
259  *
260  * Important traits for hash tables.
261  *
262  * @tparam _Cache_hash_code Boolean value. True if the value of
263  * the hash function is stored along with the value. This is a
264  * time-space tradeoff. Storing it may improve lookup speed by
265  * reducing the number of times we need to call the _Hash or _Equal
266  * functors.
267  *
268  * @tparam _Constant_iterators Boolean value. True if iterator and
269  * const_iterator are both constant iterator types. This is true
270  * for unordered_set and unordered_multiset, false for
271  * unordered_map and unordered_multimap.
272  *
273  * @tparam _Unique_keys Boolean value. True if the return value
274  * of _Hashtable::count(k) is always at most one, false if it may
275  * be an arbitrary number. This is true for unordered_set and
276  * unordered_map, false for unordered_multiset and
277  * unordered_multimap.
278  */
279  template<bool _Cache_hash_code, bool _Constant_iterators, bool _Unique_keys>
280  struct _Hashtable_traits
281  {
282  using __hash_cached = __bool_constant<_Cache_hash_code>;
283  using __constant_iterators = __bool_constant<_Constant_iterators>;
284  using __unique_keys = __bool_constant<_Unique_keys>;
285  };
286 
287  /**
288  * struct _Hashtable_hash_traits
289  *
290  * Important traits for hash tables depending on associated hasher.
291  *
292  */
293  template<typename _Hash>
294  struct _Hashtable_hash_traits
295  {
296  static constexpr std::size_t
297  __small_size_threshold() noexcept
298  { return std::__is_fast_hash<_Hash>::value ? 0 : 20; }
299  };
300 
301  /**
302  * struct _Hash_node_base
303  *
304  * Nodes, used to wrap elements stored in the hash table. A policy
305  * template parameter of class template _Hashtable controls whether
306  * nodes also store a hash code. In some cases (e.g. strings) this
307  * may be a performance win.
308  */
309  struct _Hash_node_base
310  {
311  _Hash_node_base* _M_nxt;
312 
313  _Hash_node_base() noexcept : _M_nxt() { }
314 
315  _Hash_node_base(_Hash_node_base* __next) noexcept : _M_nxt(__next) { }
316  };
317 
318  /**
319  * struct _Hash_node_value_base
320  *
321  * Node type with the value to store.
322  */
323  template<typename _Value>
324  struct _Hash_node_value_base
325  {
326  typedef _Value value_type;
327 
328  __gnu_cxx::__aligned_buffer<_Value> _M_storage;
329 
330  _Value*
331  _M_valptr() noexcept
332  { return _M_storage._M_ptr(); }
333 
334  const _Value*
335  _M_valptr() const noexcept
336  { return _M_storage._M_ptr(); }
337 
338  _Value&
339  _M_v() noexcept
340  { return *_M_valptr(); }
341 
342  const _Value&
343  _M_v() const noexcept
344  { return *_M_valptr(); }
345  };
346 
347  /**
348  * Primary template struct _Hash_node_code_cache.
349  */
350  template<bool _Cache_hash_code>
351  struct _Hash_node_code_cache
352  { };
353 
354  /**
355  * Specialization for node with cache, struct _Hash_node_code_cache.
356  */
357  template<>
358  struct _Hash_node_code_cache<true>
359  { std::size_t _M_hash_code; };
360 
361  template<typename _Value, bool _Cache_hash_code>
362  struct _Hash_node_value
363  : _Hash_node_value_base<_Value>
364  , _Hash_node_code_cache<_Cache_hash_code>
365  { };
366 
367  /**
368  * Primary template struct _Hash_node.
369  */
370  template<typename _Value, bool _Cache_hash_code>
371  struct _Hash_node
372  : _Hash_node_base
373  , _Hash_node_value<_Value, _Cache_hash_code>
374  {
375  _Hash_node*
376  _M_next() const noexcept
377  { return static_cast<_Hash_node*>(this->_M_nxt); }
378  };
379 
380  /// Base class for node iterators.
381  template<typename _Value, bool _Cache_hash_code>
382  struct _Node_iterator_base
383  {
384  using __node_type = _Hash_node<_Value, _Cache_hash_code>;
385 
386  __node_type* _M_cur;
387 
388  _Node_iterator_base() : _M_cur(nullptr) { }
389  _Node_iterator_base(__node_type* __p) noexcept
390  : _M_cur(__p) { }
391 
392  void
393  _M_incr() noexcept
394  { _M_cur = _M_cur->_M_next(); }
395 
396  friend bool
397  operator==(const _Node_iterator_base& __x, const _Node_iterator_base& __y)
398  noexcept
399  { return __x._M_cur == __y._M_cur; }
400 
401 #if __cpp_impl_three_way_comparison < 201907L
402  friend bool
403  operator!=(const _Node_iterator_base& __x, const _Node_iterator_base& __y)
404  noexcept
405  { return __x._M_cur != __y._M_cur; }
406 #endif
407  };
408 
409  /// Node iterators, used to iterate through all the hashtable.
410  template<typename _Value, bool __constant_iterators, bool __cache>
411  struct _Node_iterator
412  : public _Node_iterator_base<_Value, __cache>
413  {
414  private:
415  using __base_type = _Node_iterator_base<_Value, __cache>;
416  using __node_type = typename __base_type::__node_type;
417 
418  public:
419  using value_type = _Value;
420  using difference_type = std::ptrdiff_t;
421  using iterator_category = std::forward_iterator_tag;
422 
423  using pointer = __conditional_t<__constant_iterators,
424  const value_type*, value_type*>;
425 
426  using reference = __conditional_t<__constant_iterators,
427  const value_type&, value_type&>;
428 
429  _Node_iterator() = default;
430 
431  explicit
432  _Node_iterator(__node_type* __p) noexcept
433  : __base_type(__p) { }
434 
435  reference
436  operator*() const noexcept
437  { return this->_M_cur->_M_v(); }
438 
439  pointer
440  operator->() const noexcept
441  { return this->_M_cur->_M_valptr(); }
442 
443  _Node_iterator&
444  operator++() noexcept
445  {
446  this->_M_incr();
447  return *this;
448  }
449 
450  _Node_iterator
451  operator++(int) noexcept
452  {
453  _Node_iterator __tmp(*this);
454  this->_M_incr();
455  return __tmp;
456  }
457  };
458 
459  /// Node const_iterators, used to iterate through all the hashtable.
460  template<typename _Value, bool __constant_iterators, bool __cache>
461  struct _Node_const_iterator
462  : public _Node_iterator_base<_Value, __cache>
463  {
464  private:
465  using __base_type = _Node_iterator_base<_Value, __cache>;
466  using __node_type = typename __base_type::__node_type;
467 
468  public:
469  typedef _Value value_type;
470  typedef std::ptrdiff_t difference_type;
471  typedef std::forward_iterator_tag iterator_category;
472 
473  typedef const value_type* pointer;
474  typedef const value_type& reference;
475 
476  _Node_const_iterator() = default;
477 
478  explicit
479  _Node_const_iterator(__node_type* __p) noexcept
480  : __base_type(__p) { }
481 
482  _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators,
483  __cache>& __x) noexcept
484  : __base_type(__x._M_cur) { }
485 
486  reference
487  operator*() const noexcept
488  { return this->_M_cur->_M_v(); }
489 
490  pointer
491  operator->() const noexcept
492  { return this->_M_cur->_M_valptr(); }
493 
494  _Node_const_iterator&
495  operator++() noexcept
496  {
497  this->_M_incr();
498  return *this;
499  }
500 
501  _Node_const_iterator
502  operator++(int) noexcept
503  {
504  _Node_const_iterator __tmp(*this);
505  this->_M_incr();
506  return __tmp;
507  }
508  };
509 
510  // Many of class template _Hashtable's template parameters are policy
511  // classes. These are defaults for the policies.
512 
513  /// Default range hashing function: use division to fold a large number
514  /// into the range [0, N).
515  struct _Mod_range_hashing
516  {
517  typedef std::size_t first_argument_type;
518  typedef std::size_t second_argument_type;
519  typedef std::size_t result_type;
520 
521  result_type
522  operator()(first_argument_type __num,
523  second_argument_type __den) const noexcept
524  { return __num % __den; }
525  };
526 
527  /// Default ranged hash function H. In principle it should be a
528  /// function object composed from objects of type H1 and H2 such that
529  /// h(k, N) = h2(h1(k), N), but that would mean making extra copies of
530  /// h1 and h2. So instead we'll just use a tag to tell class template
531  /// hashtable to do that composition.
532  struct _Default_ranged_hash { };
533 
534  /// Default value for rehash policy. Bucket size is (usually) the
535  /// smallest prime that keeps the load factor small enough.
536  struct _Prime_rehash_policy
537  {
538  using __has_load_factor = true_type;
539 
540  _Prime_rehash_policy(float __z = 1.0) noexcept
541  : _M_max_load_factor(__z), _M_next_resize(0) { }
542 
543  float
544  max_load_factor() const noexcept
545  { return _M_max_load_factor; }
546 
547  // Return a bucket size no smaller than n.
548  std::size_t
549  _M_next_bkt(std::size_t __n) const;
550 
551  // Return a bucket count appropriate for n elements
552  std::size_t
553  _M_bkt_for_elements(std::size_t __n) const
554  { return __builtin_ceil(__n / (double)_M_max_load_factor); }
555 
556  // __n_bkt is current bucket count, __n_elt is current element count,
557  // and __n_ins is number of elements to be inserted. Do we need to
558  // increase bucket count? If so, return make_pair(true, n), where n
559  // is the new bucket count. If not, return make_pair(false, 0).
561  _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
562  std::size_t __n_ins) const;
563 
564  typedef std::size_t _State;
565 
566  _State
567  _M_state() const
568  { return _M_next_resize; }
569 
570  void
571  _M_reset() noexcept
572  { _M_next_resize = 0; }
573 
574  void
575  _M_reset(_State __state)
576  { _M_next_resize = __state; }
577 
578  static const std::size_t _S_growth_factor = 2;
579 
580  float _M_max_load_factor;
581  mutable std::size_t _M_next_resize;
582  };
583 
584  /// Range hashing function assuming that second arg is a power of 2.
585  struct _Mask_range_hashing
586  {
587  typedef std::size_t first_argument_type;
588  typedef std::size_t second_argument_type;
589  typedef std::size_t result_type;
590 
591  result_type
592  operator()(first_argument_type __num,
593  second_argument_type __den) const noexcept
594  { return __num & (__den - 1); }
595  };
596 
597  /// Compute closest power of 2 not less than __n
598  inline std::size_t
599  __clp2(std::size_t __n) noexcept
600  {
602  // Equivalent to return __n ? std::bit_ceil(__n) : 0;
603  if (__n < 2)
604  return __n;
605  const unsigned __lz = sizeof(size_t) > sizeof(long)
606  ? __builtin_clzll(__n - 1ull)
607  : __builtin_clzl(__n - 1ul);
608  // Doing two shifts avoids undefined behaviour when __lz == 0.
609  return (size_t(1) << (__int_traits<size_t>::__digits - __lz - 1)) << 1;
610  }
611 
612  /// Rehash policy providing power of 2 bucket numbers. Avoids modulo
613  /// operations.
614  struct _Power2_rehash_policy
615  {
616  using __has_load_factor = true_type;
617 
618  _Power2_rehash_policy(float __z = 1.0) noexcept
619  : _M_max_load_factor(__z), _M_next_resize(0) { }
620 
621  float
622  max_load_factor() const noexcept
623  { return _M_max_load_factor; }
624 
625  // Return a bucket size no smaller than n (as long as n is not above the
626  // highest power of 2).
627  std::size_t
628  _M_next_bkt(std::size_t __n) noexcept
629  {
630  if (__n == 0)
631  // Special case on container 1st initialization with 0 bucket count
632  // hint. We keep _M_next_resize to 0 to make sure that next time we
633  // want to add an element allocation will take place.
634  return 1;
635 
636  const auto __max_width = std::min<size_t>(sizeof(size_t), 8);
637  const auto __max_bkt = size_t(1) << (__max_width * __CHAR_BIT__ - 1);
638  std::size_t __res = __clp2(__n);
639 
640  if (__res == 0)
641  __res = __max_bkt;
642  else if (__res == 1)
643  // If __res is 1 we force it to 2 to make sure there will be an
644  // allocation so that nothing need to be stored in the initial
645  // single bucket
646  __res = 2;
647 
648  if (__res == __max_bkt)
649  // Set next resize to the max value so that we never try to rehash again
650  // as we already reach the biggest possible bucket number.
651  // Note that it might result in max_load_factor not being respected.
652  _M_next_resize = size_t(-1);
653  else
654  _M_next_resize
655  = __builtin_floor(__res * (double)_M_max_load_factor);
656 
657  return __res;
658  }
659 
660  // Return a bucket count appropriate for n elements
661  std::size_t
662  _M_bkt_for_elements(std::size_t __n) const noexcept
663  { return __builtin_ceil(__n / (double)_M_max_load_factor); }
664 
665  // __n_bkt is current bucket count, __n_elt is current element count,
666  // and __n_ins is number of elements to be inserted. Do we need to
667  // increase bucket count? If so, return make_pair(true, n), where n
668  // is the new bucket count. If not, return make_pair(false, 0).
670  _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
671  std::size_t __n_ins) noexcept
672  {
673  if (__n_elt + __n_ins > _M_next_resize)
674  {
675  // If _M_next_resize is 0 it means that we have nothing allocated so
676  // far and that we start inserting elements. In this case we start
677  // with an initial bucket size of 11.
678  double __min_bkts
679  = std::max<std::size_t>(__n_elt + __n_ins, _M_next_resize ? 0 : 11)
680  / (double)_M_max_load_factor;
681  if (__min_bkts >= __n_bkt)
682  return { true,
683  _M_next_bkt(std::max<std::size_t>(__builtin_floor(__min_bkts) + 1,
684  __n_bkt * _S_growth_factor)) };
685 
686  _M_next_resize
687  = __builtin_floor(__n_bkt * (double)_M_max_load_factor);
688  return { false, 0 };
689  }
690  else
691  return { false, 0 };
692  }
693 
694  typedef std::size_t _State;
695 
696  _State
697  _M_state() const noexcept
698  { return _M_next_resize; }
699 
700  void
701  _M_reset() noexcept
702  { _M_next_resize = 0; }
703 
704  void
705  _M_reset(_State __state) noexcept
706  { _M_next_resize = __state; }
707 
708  static const std::size_t _S_growth_factor = 2;
709 
710  float _M_max_load_factor;
711  std::size_t _M_next_resize;
712  };
713 
714  // Base classes for std::_Hashtable. We define these base classes
715  // because in some cases we want to do different things depending on
716  // the value of a policy class. In some cases the policy class
717  // affects which member functions and nested typedefs are defined;
718  // we handle that by specializing base class templates. Several of
719  // the base class templates need to access other members of class
720  // template _Hashtable, so we use a variant of the "Curiously
721  // Recurring Template Pattern" (CRTP) technique.
722 
723  /**
724  * Primary class template _Map_base.
725  *
726  * If the hashtable has a value type of the form pair<const T1, T2> and
727  * a key extraction policy (_ExtractKey) that returns the first part
728  * of the pair, the hashtable gets a mapped_type typedef. If it
729  * satisfies those criteria and also has unique keys, then it also
730  * gets an operator[].
731  */
732  template<typename _Key, typename _Value, typename _Alloc,
733  typename _ExtractKey, typename _Equal,
734  typename _Hash, typename _RangeHash, typename _Unused,
735  typename _RehashPolicy, typename _Traits,
736  bool _Unique_keys = _Traits::__unique_keys::value>
737  struct _Map_base { };
738 
739  /// Partial specialization, __unique_keys set to false, std::pair value type.
740  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
741  typename _Hash, typename _RangeHash, typename _Unused,
742  typename _RehashPolicy, typename _Traits>
743  struct _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
744  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
745  {
746  using mapped_type = _Val;
747  };
748 
749  /// Partial specialization, __unique_keys set to true.
750  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
751  typename _Hash, typename _RangeHash, typename _Unused,
752  typename _RehashPolicy, typename _Traits>
753  struct _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
754  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>
755  {
756  private:
757  using __hashtable_base = _Hashtable_base<_Key, pair<const _Key, _Val>,
758  _Select1st, _Equal, _Hash,
759  _RangeHash, _Unused,
760  _Traits>;
761 
762  using __hashtable = _Hashtable<_Key, pair<const _Key, _Val>, _Alloc,
763  _Select1st, _Equal, _Hash, _RangeHash,
764  _Unused, _RehashPolicy, _Traits>;
765 
766  using __hash_code = typename __hashtable_base::__hash_code;
767 
768  public:
769  using key_type = typename __hashtable_base::key_type;
770  using mapped_type = _Val;
771 
772  mapped_type&
773  operator[](const key_type& __k);
774 
775  mapped_type&
776  operator[](key_type&& __k);
777 
778  // _GLIBCXX_RESOLVE_LIB_DEFECTS
779  // DR 761. unordered_map needs an at() member function.
780  mapped_type&
781  at(const key_type& __k)
782  {
783  auto __ite = static_cast<__hashtable*>(this)->find(__k);
784  if (!__ite._M_cur)
785  __throw_out_of_range(__N("unordered_map::at"));
786  return __ite->second;
787  }
788 
789  const mapped_type&
790  at(const key_type& __k) const
791  {
792  auto __ite = static_cast<const __hashtable*>(this)->find(__k);
793  if (!__ite._M_cur)
794  __throw_out_of_range(__N("unordered_map::at"));
795  return __ite->second;
796  }
797  };
798 
799  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
800  typename _Hash, typename _RangeHash, typename _Unused,
801  typename _RehashPolicy, typename _Traits>
802  auto
803  _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
804  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
805  operator[](const key_type& __k)
806  -> mapped_type&
807  {
808  __hashtable* __h = static_cast<__hashtable*>(this);
809  __hash_code __code = __h->_M_hash_code(__k);
810  std::size_t __bkt = __h->_M_bucket_index(__code);
811  if (auto __node = __h->_M_find_node(__bkt, __k, __code))
812  return __node->_M_v().second;
813 
814  typename __hashtable::_Scoped_node __node {
815  __h,
818  std::tuple<>()
819  };
820  auto __pos
821  = __h->_M_insert_unique_node(__bkt, __code, __node._M_node);
822  __node._M_node = nullptr;
823  return __pos->second;
824  }
825 
826  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
827  typename _Hash, typename _RangeHash, typename _Unused,
828  typename _RehashPolicy, typename _Traits>
829  auto
830  _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
831  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
832  operator[](key_type&& __k)
833  -> mapped_type&
834  {
835  __hashtable* __h = static_cast<__hashtable*>(this);
836  __hash_code __code = __h->_M_hash_code(__k);
837  std::size_t __bkt = __h->_M_bucket_index(__code);
838  if (auto __node = __h->_M_find_node(__bkt, __k, __code))
839  return __node->_M_v().second;
840 
841  typename __hashtable::_Scoped_node __node {
842  __h,
845  std::tuple<>()
846  };
847  auto __pos
848  = __h->_M_insert_unique_node(__bkt, __code, __node._M_node);
849  __node._M_node = nullptr;
850  return __pos->second;
851  }
852 
853  // Partial specialization for unordered_map<const T, U>, see PR 104174.
854  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
855  typename _Hash, typename _RangeHash, typename _Unused,
856  typename _RehashPolicy, typename _Traits, bool __uniq>
857  struct _Map_base<const _Key, pair<const _Key, _Val>,
858  _Alloc, _Select1st, _Equal, _Hash,
859  _RangeHash, _Unused, _RehashPolicy, _Traits, __uniq>
860  : _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal, _Hash,
861  _RangeHash, _Unused, _RehashPolicy, _Traits, __uniq>
862  { };
863 
864  /**
865  * Primary class template _Insert_base.
866  *
867  * Defines @c insert member functions appropriate to all _Hashtables.
868  */
869  template<typename _Key, typename _Value, typename _Alloc,
870  typename _ExtractKey, typename _Equal,
871  typename _Hash, typename _RangeHash, typename _Unused,
872  typename _RehashPolicy, typename _Traits>
873  struct _Insert_base
874  {
875  protected:
876  using __hashtable_base = _Hashtable_base<_Key, _Value, _ExtractKey,
877  _Equal, _Hash, _RangeHash,
878  _Unused, _Traits>;
879 
880  using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
881  _Hash, _RangeHash,
882  _Unused, _RehashPolicy, _Traits>;
883 
884  using __hash_cached = typename _Traits::__hash_cached;
885  using __constant_iterators = typename _Traits::__constant_iterators;
886 
887  using __hashtable_alloc = _Hashtable_alloc<
888  __alloc_rebind<_Alloc, _Hash_node<_Value,
889  __hash_cached::value>>>;
890 
891  using value_type = typename __hashtable_base::value_type;
892  using size_type = typename __hashtable_base::size_type;
893 
894  using __unique_keys = typename _Traits::__unique_keys;
895  using __node_alloc_type = typename __hashtable_alloc::__node_alloc_type;
896  using __node_gen_type = _AllocNode<__node_alloc_type>;
897 
898  __hashtable&
899  _M_conjure_hashtable()
900  { return *(static_cast<__hashtable*>(this)); }
901 
902  template<typename _InputIterator, typename _NodeGetter>
903  void
904  _M_insert_range(_InputIterator __first, _InputIterator __last,
905  const _NodeGetter&, true_type __uks);
906 
907  template<typename _InputIterator, typename _NodeGetter>
908  void
909  _M_insert_range(_InputIterator __first, _InputIterator __last,
910  const _NodeGetter&, false_type __uks);
911 
912  public:
913  using iterator = _Node_iterator<_Value, __constant_iterators::value,
914  __hash_cached::value>;
915 
916  using const_iterator = _Node_const_iterator<_Value,
917  __constant_iterators::value,
918  __hash_cached::value>;
919 
920  using __ireturn_type = __conditional_t<__unique_keys::value,
922  iterator>;
923 
924  __ireturn_type
925  insert(const value_type& __v)
926  {
927  __hashtable& __h = _M_conjure_hashtable();
928  __node_gen_type __node_gen(__h);
929  return __h._M_insert(__v, __node_gen, __unique_keys{});
930  }
931 
932  iterator
933  insert(const_iterator __hint, const value_type& __v)
934  {
935  __hashtable& __h = _M_conjure_hashtable();
936  __node_gen_type __node_gen(__h);
937  return __h._M_insert(__hint, __v, __node_gen, __unique_keys{});
938  }
939 
940  template<typename _KType, typename... _Args>
942  try_emplace(const_iterator, _KType&& __k, _Args&&... __args)
943  {
944  __hashtable& __h = _M_conjure_hashtable();
945  auto __code = __h._M_hash_code(__k);
946  std::size_t __bkt = __h._M_bucket_index(__code);
947  if (auto __node = __h._M_find_node(__bkt, __k, __code))
948  return { iterator(__node), false };
949 
950  typename __hashtable::_Scoped_node __node {
951  &__h,
953  std::forward_as_tuple(std::forward<_KType>(__k)),
954  std::forward_as_tuple(std::forward<_Args>(__args)...)
955  };
956  auto __it
957  = __h._M_insert_unique_node(__bkt, __code, __node._M_node);
958  __node._M_node = nullptr;
959  return { __it, true };
960  }
961 
962  void
963  insert(initializer_list<value_type> __l)
964  { this->insert(__l.begin(), __l.end()); }
965 
966  template<typename _InputIterator>
967  void
968  insert(_InputIterator __first, _InputIterator __last)
969  {
970  __hashtable& __h = _M_conjure_hashtable();
971  __node_gen_type __node_gen(__h);
972  return _M_insert_range(__first, __last, __node_gen, __unique_keys{});
973  }
974  };
975 
976  template<typename _Key, typename _Value, typename _Alloc,
977  typename _ExtractKey, typename _Equal,
978  typename _Hash, typename _RangeHash, typename _Unused,
979  typename _RehashPolicy, typename _Traits>
980  template<typename _InputIterator, typename _NodeGetter>
981  void
982  _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
983  _Hash, _RangeHash, _Unused,
984  _RehashPolicy, _Traits>::
985  _M_insert_range(_InputIterator __first, _InputIterator __last,
986  const _NodeGetter& __node_gen, true_type __uks)
987  {
988  __hashtable& __h = _M_conjure_hashtable();
989  for (; __first != __last; ++__first)
990  __h._M_insert(*__first, __node_gen, __uks);
991  }
992 
993  template<typename _Key, typename _Value, typename _Alloc,
994  typename _ExtractKey, typename _Equal,
995  typename _Hash, typename _RangeHash, typename _Unused,
996  typename _RehashPolicy, typename _Traits>
997  template<typename _InputIterator, typename _NodeGetter>
998  void
999  _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1000  _Hash, _RangeHash, _Unused,
1001  _RehashPolicy, _Traits>::
1002  _M_insert_range(_InputIterator __first, _InputIterator __last,
1003  const _NodeGetter& __node_gen, false_type __uks)
1004  {
1005  using __rehash_type = typename __hashtable::__rehash_type;
1006  using __rehash_state = typename __hashtable::__rehash_state;
1007  using pair_type = std::pair<bool, std::size_t>;
1008 
1009  size_type __n_elt = __detail::__distance_fw(__first, __last);
1010  if (__n_elt == 0)
1011  return;
1012 
1013  __hashtable& __h = _M_conjure_hashtable();
1014  __rehash_type& __rehash = __h._M_rehash_policy;
1015  const __rehash_state& __saved_state = __rehash._M_state();
1016  pair_type __do_rehash = __rehash._M_need_rehash(__h._M_bucket_count,
1017  __h._M_element_count,
1018  __n_elt);
1019 
1020  if (__do_rehash.first)
1021  __h._M_rehash(__do_rehash.second, __saved_state);
1022 
1023  for (; __first != __last; ++__first)
1024  __h._M_insert(*__first, __node_gen, __uks);
1025  }
1026 
1027  /**
1028  * Primary class template _Insert.
1029  *
1030  * Defines @c insert member functions that depend on _Hashtable policies,
1031  * via partial specializations.
1032  */
1033  template<typename _Key, typename _Value, typename _Alloc,
1034  typename _ExtractKey, typename _Equal,
1035  typename _Hash, typename _RangeHash, typename _Unused,
1036  typename _RehashPolicy, typename _Traits,
1037  bool _Constant_iterators = _Traits::__constant_iterators::value>
1038  struct _Insert;
1039 
1040  /// Specialization.
1041  template<typename _Key, typename _Value, typename _Alloc,
1042  typename _ExtractKey, typename _Equal,
1043  typename _Hash, typename _RangeHash, typename _Unused,
1044  typename _RehashPolicy, typename _Traits>
1045  struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1046  _Hash, _RangeHash, _Unused,
1047  _RehashPolicy, _Traits, true>
1048  : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1049  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>
1050  {
1051  using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
1052  _Equal, _Hash, _RangeHash, _Unused,
1053  _RehashPolicy, _Traits>;
1054 
1055  using value_type = typename __base_type::value_type;
1056  using iterator = typename __base_type::iterator;
1057  using const_iterator = typename __base_type::const_iterator;
1058  using __ireturn_type = typename __base_type::__ireturn_type;
1059 
1060  using __unique_keys = typename __base_type::__unique_keys;
1061  using __hashtable = typename __base_type::__hashtable;
1062  using __node_gen_type = typename __base_type::__node_gen_type;
1063 
1064  using __base_type::insert;
1065 
1066  __ireturn_type
1067  insert(value_type&& __v)
1068  {
1069  __hashtable& __h = this->_M_conjure_hashtable();
1070  __node_gen_type __node_gen(__h);
1071  return __h._M_insert(std::move(__v), __node_gen, __unique_keys{});
1072  }
1073 
1074  iterator
1075  insert(const_iterator __hint, value_type&& __v)
1076  {
1077  __hashtable& __h = this->_M_conjure_hashtable();
1078  __node_gen_type __node_gen(__h);
1079  return __h._M_insert(__hint, std::move(__v), __node_gen,
1080  __unique_keys{});
1081  }
1082  };
1083 
1084  /// Specialization.
1085  template<typename _Key, typename _Value, typename _Alloc,
1086  typename _ExtractKey, typename _Equal,
1087  typename _Hash, typename _RangeHash, typename _Unused,
1088  typename _RehashPolicy, typename _Traits>
1089  struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1090  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
1091  : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1092  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>
1093  {
1094  using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
1095  _Equal, _Hash, _RangeHash, _Unused,
1096  _RehashPolicy, _Traits>;
1097  using value_type = typename __base_type::value_type;
1098  using iterator = typename __base_type::iterator;
1099  using const_iterator = typename __base_type::const_iterator;
1100 
1101  using __unique_keys = typename __base_type::__unique_keys;
1102  using __hashtable = typename __base_type::__hashtable;
1103  using __ireturn_type = typename __base_type::__ireturn_type;
1104 
1105  using __base_type::insert;
1106 
1107  template<typename _Pair>
1109 
1110  template<typename _Pair>
1111  using _IFcons = std::enable_if<__is_cons<_Pair>::value>;
1112 
1113  template<typename _Pair>
1114  using _IFconsp = typename _IFcons<_Pair>::type;
1115 
1116  template<typename _Pair, typename = _IFconsp<_Pair>>
1117  __ireturn_type
1118  insert(_Pair&& __v)
1119  {
1120  __hashtable& __h = this->_M_conjure_hashtable();
1121  return __h._M_emplace(__unique_keys{}, std::forward<_Pair>(__v));
1122  }
1123 
1124  template<typename _Pair, typename = _IFconsp<_Pair>>
1125  iterator
1126  insert(const_iterator __hint, _Pair&& __v)
1127  {
1128  __hashtable& __h = this->_M_conjure_hashtable();
1129  return __h._M_emplace(__hint, __unique_keys{},
1130  std::forward<_Pair>(__v));
1131  }
1132  };
1133 
1134  template<typename _Policy>
1135  using __has_load_factor = typename _Policy::__has_load_factor;
1136 
1137  /**
1138  * Primary class template _Rehash_base.
1139  *
1140  * Give hashtable the max_load_factor functions and reserve iff the
1141  * rehash policy supports it.
1142  */
1143  template<typename _Key, typename _Value, typename _Alloc,
1144  typename _ExtractKey, typename _Equal,
1145  typename _Hash, typename _RangeHash, typename _Unused,
1146  typename _RehashPolicy, typename _Traits,
1147  typename =
1148  __detected_or_t<false_type, __has_load_factor, _RehashPolicy>>
1149  struct _Rehash_base;
1150 
1151  /// Specialization when rehash policy doesn't provide load factor management.
1152  template<typename _Key, typename _Value, typename _Alloc,
1153  typename _ExtractKey, typename _Equal,
1154  typename _Hash, typename _RangeHash, typename _Unused,
1155  typename _RehashPolicy, typename _Traits>
1156  struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1157  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits,
1158  false_type /* Has load factor */>
1159  {
1160  };
1161 
1162  /// Specialization when rehash policy provide load factor management.
1163  template<typename _Key, typename _Value, typename _Alloc,
1164  typename _ExtractKey, typename _Equal,
1165  typename _Hash, typename _RangeHash, typename _Unused,
1166  typename _RehashPolicy, typename _Traits>
1167  struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1168  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits,
1169  true_type /* Has load factor */>
1170  {
1171  private:
1172  using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
1173  _Equal, _Hash, _RangeHash, _Unused,
1174  _RehashPolicy, _Traits>;
1175 
1176  public:
1177  float
1178  max_load_factor() const noexcept
1179  {
1180  const __hashtable* __this = static_cast<const __hashtable*>(this);
1181  return __this->__rehash_policy().max_load_factor();
1182  }
1183 
1184  void
1185  max_load_factor(float __z)
1186  {
1187  __hashtable* __this = static_cast<__hashtable*>(this);
1188  __this->__rehash_policy(_RehashPolicy(__z));
1189  }
1190 
1191  void
1192  reserve(std::size_t __n)
1193  {
1194  __hashtable* __this = static_cast<__hashtable*>(this);
1195  __this->rehash(__this->__rehash_policy()._M_bkt_for_elements(__n));
1196  }
1197  };
1198 
1199  /**
1200  * Primary class template _Hashtable_ebo_helper.
1201  *
1202  * Helper class using EBO when it is not forbidden (the type is not
1203  * final) and when it is worth it (the type is empty.)
1204  */
1205  template<int _Nm, typename _Tp,
1206  bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
1207  struct _Hashtable_ebo_helper;
1208 
1209  /// Specialization using EBO.
1210  template<int _Nm, typename _Tp>
1211  struct _Hashtable_ebo_helper<_Nm, _Tp, true>
1212  : private _Tp
1213  {
1214  _Hashtable_ebo_helper() noexcept(noexcept(_Tp())) : _Tp() { }
1215 
1216  template<typename _OtherTp>
1217  _Hashtable_ebo_helper(_OtherTp&& __tp)
1218  : _Tp(std::forward<_OtherTp>(__tp))
1219  { }
1220 
1221  const _Tp& _M_cget() const { return static_cast<const _Tp&>(*this); }
1222  _Tp& _M_get() { return static_cast<_Tp&>(*this); }
1223  };
1224 
1225  /// Specialization not using EBO.
1226  template<int _Nm, typename _Tp>
1227  struct _Hashtable_ebo_helper<_Nm, _Tp, false>
1228  {
1229  _Hashtable_ebo_helper() = default;
1230 
1231  template<typename _OtherTp>
1232  _Hashtable_ebo_helper(_OtherTp&& __tp)
1233  : _M_tp(std::forward<_OtherTp>(__tp))
1234  { }
1235 
1236  const _Tp& _M_cget() const { return _M_tp; }
1237  _Tp& _M_get() { return _M_tp; }
1238 
1239  private:
1240  _Tp _M_tp{};
1241  };
1242 
1243  /**
1244  * Primary class template _Local_iterator_base.
1245  *
1246  * Base class for local iterators, used to iterate within a bucket
1247  * but not between buckets.
1248  */
1249  template<typename _Key, typename _Value, typename _ExtractKey,
1250  typename _Hash, typename _RangeHash, typename _Unused,
1251  bool __cache_hash_code>
1252  struct _Local_iterator_base;
1253 
1254  /**
1255  * Primary class template _Hash_code_base.
1256  *
1257  * Encapsulates two policy issues that aren't quite orthogonal.
1258  * (1) the difference between using a ranged hash function and using
1259  * the combination of a hash function and a range-hashing function.
1260  * In the former case we don't have such things as hash codes, so
1261  * we have a dummy type as placeholder.
1262  * (2) Whether or not we cache hash codes. Caching hash codes is
1263  * meaningless if we have a ranged hash function.
1264  *
1265  * We also put the key extraction objects here, for convenience.
1266  * Each specialization derives from one or more of the template
1267  * parameters to benefit from Ebo. This is important as this type
1268  * is inherited in some cases by the _Local_iterator_base type used
1269  * to implement local_iterator and const_local_iterator. As with
1270  * any iterator type we prefer to make it as small as possible.
1271  */
1272  template<typename _Key, typename _Value, typename _ExtractKey,
1273  typename _Hash, typename _RangeHash, typename _Unused,
1274  bool __cache_hash_code>
1275  struct _Hash_code_base
1276  : private _Hashtable_ebo_helper<1, _Hash>
1277  {
1278  private:
1279  using __ebo_hash = _Hashtable_ebo_helper<1, _Hash>;
1280 
1281  // Gives the local iterator implementation access to _M_bucket_index().
1282  friend struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1283  _Hash, _RangeHash, _Unused, false>;
1284 
1285  public:
1286  typedef _Hash hasher;
1287 
1288  hasher
1289  hash_function() const
1290  { return _M_hash(); }
1291 
1292  protected:
1293  typedef std::size_t __hash_code;
1294 
1295  // We need the default constructor for the local iterators and _Hashtable
1296  // default constructor.
1297  _Hash_code_base() = default;
1298 
1299  _Hash_code_base(const _Hash& __hash) : __ebo_hash(__hash) { }
1300 
1301  __hash_code
1302  _M_hash_code(const _Key& __k) const
1303  {
1304  static_assert(__is_invocable<const _Hash&, const _Key&>{},
1305  "hash function must be invocable with an argument of key type");
1306  return _M_hash()(__k);
1307  }
1308 
1309  template<typename _Kt>
1310  __hash_code
1311  _M_hash_code_tr(const _Kt& __k) const
1312  {
1313  static_assert(__is_invocable<const _Hash&, const _Kt&>{},
1314  "hash function must be invocable with an argument of key type");
1315  return _M_hash()(__k);
1316  }
1317 
1318  __hash_code
1319  _M_hash_code(const _Hash&,
1320  const _Hash_node_value<_Value, true>& __n) const
1321  { return __n._M_hash_code; }
1322 
1323  // Compute hash code using _Hash as __n _M_hash_code, if present, was
1324  // computed using _H2.
1325  template<typename _H2>
1326  __hash_code
1327  _M_hash_code(const _H2&,
1328  const _Hash_node_value<_Value, __cache_hash_code>& __n) const
1329  { return _M_hash_code(_ExtractKey{}(__n._M_v())); }
1330 
1331  __hash_code
1332  _M_hash_code(const _Hash_node_value<_Value, false>& __n) const
1333  { return _M_hash_code(_ExtractKey{}(__n._M_v())); }
1334 
1335  __hash_code
1336  _M_hash_code(const _Hash_node_value<_Value, true>& __n) const
1337  { return __n._M_hash_code; }
1338 
1339  std::size_t
1340  _M_bucket_index(__hash_code __c, std::size_t __bkt_count) const
1341  { return _RangeHash{}(__c, __bkt_count); }
1342 
1343  std::size_t
1344  _M_bucket_index(const _Hash_node_value<_Value, false>& __n,
1345  std::size_t __bkt_count) const
1346  noexcept( noexcept(declval<const _Hash&>()(declval<const _Key&>()))
1347  && noexcept(declval<const _RangeHash&>()((__hash_code)0,
1348  (std::size_t)0)) )
1349  {
1350  return _RangeHash{}(_M_hash_code(_ExtractKey{}(__n._M_v())),
1351  __bkt_count);
1352  }
1353 
1354  std::size_t
1355  _M_bucket_index(const _Hash_node_value<_Value, true>& __n,
1356  std::size_t __bkt_count) const
1357  noexcept( noexcept(declval<const _RangeHash&>()((__hash_code)0,
1358  (std::size_t)0)) )
1359  { return _RangeHash{}(__n._M_hash_code, __bkt_count); }
1360 
1361  void
1362  _M_store_code(_Hash_node_code_cache<false>&, __hash_code) const
1363  { }
1364 
1365  void
1366  _M_copy_code(_Hash_node_code_cache<false>&,
1367  const _Hash_node_code_cache<false>&) const
1368  { }
1369 
1370  void
1371  _M_store_code(_Hash_node_code_cache<true>& __n, __hash_code __c) const
1372  { __n._M_hash_code = __c; }
1373 
1374  void
1375  _M_copy_code(_Hash_node_code_cache<true>& __to,
1376  const _Hash_node_code_cache<true>& __from) const
1377  { __to._M_hash_code = __from._M_hash_code; }
1378 
1379  void
1380  _M_swap(_Hash_code_base& __x)
1381  { std::swap(__ebo_hash::_M_get(), __x.__ebo_hash::_M_get()); }
1382 
1383  const _Hash&
1384  _M_hash() const { return __ebo_hash::_M_cget(); }
1385  };
1386 
1387  /// Partial specialization used when nodes contain a cached hash code.
1388  template<typename _Key, typename _Value, typename _ExtractKey,
1389  typename _Hash, typename _RangeHash, typename _Unused>
1390  struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1391  _Hash, _RangeHash, _Unused, true>
1392  : public _Node_iterator_base<_Value, true>
1393  {
1394  protected:
1395  using __base_node_iter = _Node_iterator_base<_Value, true>;
1396  using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1397  _Hash, _RangeHash, _Unused, true>;
1398 
1399  _Local_iterator_base() = default;
1400  _Local_iterator_base(const __hash_code_base&,
1401  _Hash_node<_Value, true>* __p,
1402  std::size_t __bkt, std::size_t __bkt_count)
1403  : __base_node_iter(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
1404  { }
1405 
1406  void
1407  _M_incr()
1408  {
1409  __base_node_iter::_M_incr();
1410  if (this->_M_cur)
1411  {
1412  std::size_t __bkt
1413  = _RangeHash{}(this->_M_cur->_M_hash_code, _M_bucket_count);
1414  if (__bkt != _M_bucket)
1415  this->_M_cur = nullptr;
1416  }
1417  }
1418 
1419  std::size_t _M_bucket;
1420  std::size_t _M_bucket_count;
1421 
1422  public:
1423  std::size_t
1424  _M_get_bucket() const { return _M_bucket; } // for debug mode
1425  };
1426 
1427  // Uninitialized storage for a _Hash_code_base.
1428  // This type is DefaultConstructible and Assignable even if the
1429  // _Hash_code_base type isn't, so that _Local_iterator_base<..., false>
1430  // can be DefaultConstructible and Assignable.
1431  template<typename _Tp, bool _IsEmpty = std::is_empty<_Tp>::value>
1432  struct _Hash_code_storage
1433  {
1434  __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
1435 
1436  _Tp*
1437  _M_h() { return _M_storage._M_ptr(); }
1438 
1439  const _Tp*
1440  _M_h() const { return _M_storage._M_ptr(); }
1441  };
1442 
1443  // Empty partial specialization for empty _Hash_code_base types.
1444  template<typename _Tp>
1445  struct _Hash_code_storage<_Tp, true>
1446  {
1447  static_assert( std::is_empty<_Tp>::value, "Type must be empty" );
1448 
1449  // As _Tp is an empty type there will be no bytes written/read through
1450  // the cast pointer, so no strict-aliasing violation.
1451  _Tp*
1452  _M_h() { return reinterpret_cast<_Tp*>(this); }
1453 
1454  const _Tp*
1455  _M_h() const { return reinterpret_cast<const _Tp*>(this); }
1456  };
1457 
1458  template<typename _Key, typename _Value, typename _ExtractKey,
1459  typename _Hash, typename _RangeHash, typename _Unused>
1460  using __hash_code_for_local_iter
1461  = _Hash_code_storage<_Hash_code_base<_Key, _Value, _ExtractKey,
1462  _Hash, _RangeHash, _Unused, false>>;
1463 
1464  // Partial specialization used when hash codes are not cached
1465  template<typename _Key, typename _Value, typename _ExtractKey,
1466  typename _Hash, typename _RangeHash, typename _Unused>
1467  struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1468  _Hash, _RangeHash, _Unused, false>
1469  : __hash_code_for_local_iter<_Key, _Value, _ExtractKey, _Hash, _RangeHash,
1470  _Unused>
1471  , _Node_iterator_base<_Value, false>
1472  {
1473  protected:
1474  using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1475  _Hash, _RangeHash, _Unused, false>;
1476  using __node_iter_base = _Node_iterator_base<_Value, false>;
1477 
1478  _Local_iterator_base() : _M_bucket_count(-1) { }
1479 
1480  _Local_iterator_base(const __hash_code_base& __base,
1481  _Hash_node<_Value, false>* __p,
1482  std::size_t __bkt, std::size_t __bkt_count)
1483  : __node_iter_base(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
1484  { _M_init(__base); }
1485 
1486  ~_Local_iterator_base()
1487  {
1488  if (_M_bucket_count != size_t(-1))
1489  _M_destroy();
1490  }
1491 
1492  _Local_iterator_base(const _Local_iterator_base& __iter)
1493  : __node_iter_base(__iter._M_cur), _M_bucket(__iter._M_bucket)
1494  , _M_bucket_count(__iter._M_bucket_count)
1495  {
1496  if (_M_bucket_count != size_t(-1))
1497  _M_init(*__iter._M_h());
1498  }
1499 
1500  _Local_iterator_base&
1501  operator=(const _Local_iterator_base& __iter)
1502  {
1503  if (_M_bucket_count != -1)
1504  _M_destroy();
1505  this->_M_cur = __iter._M_cur;
1506  _M_bucket = __iter._M_bucket;
1507  _M_bucket_count = __iter._M_bucket_count;
1508  if (_M_bucket_count != -1)
1509  _M_init(*__iter._M_h());
1510  return *this;
1511  }
1512 
1513  void
1514  _M_incr()
1515  {
1516  __node_iter_base::_M_incr();
1517  if (this->_M_cur)
1518  {
1519  std::size_t __bkt = this->_M_h()->_M_bucket_index(*this->_M_cur,
1520  _M_bucket_count);
1521  if (__bkt != _M_bucket)
1522  this->_M_cur = nullptr;
1523  }
1524  }
1525 
1526  std::size_t _M_bucket;
1527  std::size_t _M_bucket_count;
1528 
1529  void
1530  _M_init(const __hash_code_base& __base)
1531  { ::new(this->_M_h()) __hash_code_base(__base); }
1532 
1533  void
1534  _M_destroy() { this->_M_h()->~__hash_code_base(); }
1535 
1536  public:
1537  std::size_t
1538  _M_get_bucket() const { return _M_bucket; } // for debug mode
1539  };
1540 
1541  /// local iterators
1542  template<typename _Key, typename _Value, typename _ExtractKey,
1543  typename _Hash, typename _RangeHash, typename _Unused,
1544  bool __constant_iterators, bool __cache>
1545  struct _Local_iterator
1546  : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1547  _Hash, _RangeHash, _Unused, __cache>
1548  {
1549  private:
1550  using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1551  _Hash, _RangeHash, _Unused, __cache>;
1552  using __hash_code_base = typename __base_type::__hash_code_base;
1553 
1554  public:
1555  using value_type = _Value;
1556  using pointer = __conditional_t<__constant_iterators,
1557  const value_type*, value_type*>;
1558  using reference = __conditional_t<__constant_iterators,
1559  const value_type&, value_type&>;
1560  using difference_type = ptrdiff_t;
1561  using iterator_category = forward_iterator_tag;
1562 
1563  _Local_iterator() = default;
1564 
1565  _Local_iterator(const __hash_code_base& __base,
1566  _Hash_node<_Value, __cache>* __n,
1567  std::size_t __bkt, std::size_t __bkt_count)
1568  : __base_type(__base, __n, __bkt, __bkt_count)
1569  { }
1570 
1571  reference
1572  operator*() const
1573  { return this->_M_cur->_M_v(); }
1574 
1575  pointer
1576  operator->() const
1577  { return this->_M_cur->_M_valptr(); }
1578 
1579  _Local_iterator&
1580  operator++()
1581  {
1582  this->_M_incr();
1583  return *this;
1584  }
1585 
1586  _Local_iterator
1587  operator++(int)
1588  {
1589  _Local_iterator __tmp(*this);
1590  this->_M_incr();
1591  return __tmp;
1592  }
1593  };
1594 
1595  /// local const_iterators
1596  template<typename _Key, typename _Value, typename _ExtractKey,
1597  typename _Hash, typename _RangeHash, typename _Unused,
1598  bool __constant_iterators, bool __cache>
1599  struct _Local_const_iterator
1600  : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1601  _Hash, _RangeHash, _Unused, __cache>
1602  {
1603  private:
1604  using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1605  _Hash, _RangeHash, _Unused, __cache>;
1606  using __hash_code_base = typename __base_type::__hash_code_base;
1607 
1608  public:
1609  typedef _Value value_type;
1610  typedef const value_type* pointer;
1611  typedef const value_type& reference;
1612  typedef std::ptrdiff_t difference_type;
1613  typedef std::forward_iterator_tag iterator_category;
1614 
1615  _Local_const_iterator() = default;
1616 
1617  _Local_const_iterator(const __hash_code_base& __base,
1618  _Hash_node<_Value, __cache>* __n,
1619  std::size_t __bkt, std::size_t __bkt_count)
1620  : __base_type(__base, __n, __bkt, __bkt_count)
1621  { }
1622 
1623  _Local_const_iterator(const _Local_iterator<_Key, _Value, _ExtractKey,
1624  _Hash, _RangeHash, _Unused,
1625  __constant_iterators,
1626  __cache>& __x)
1627  : __base_type(__x)
1628  { }
1629 
1630  reference
1631  operator*() const
1632  { return this->_M_cur->_M_v(); }
1633 
1634  pointer
1635  operator->() const
1636  { return this->_M_cur->_M_valptr(); }
1637 
1638  _Local_const_iterator&
1639  operator++()
1640  {
1641  this->_M_incr();
1642  return *this;
1643  }
1644 
1645  _Local_const_iterator
1646  operator++(int)
1647  {
1648  _Local_const_iterator __tmp(*this);
1649  this->_M_incr();
1650  return __tmp;
1651  }
1652  };
1653 
1654  /**
1655  * Primary class template _Hashtable_base.
1656  *
1657  * Helper class adding management of _Equal functor to
1658  * _Hash_code_base type.
1659  *
1660  * Base class templates are:
1661  * - __detail::_Hash_code_base
1662  * - __detail::_Hashtable_ebo_helper
1663  */
1664  template<typename _Key, typename _Value, typename _ExtractKey,
1665  typename _Equal, typename _Hash, typename _RangeHash,
1666  typename _Unused, typename _Traits>
1667  struct _Hashtable_base
1668  : public _Hash_code_base<_Key, _Value, _ExtractKey, _Hash, _RangeHash,
1669  _Unused, _Traits::__hash_cached::value>,
1670  private _Hashtable_ebo_helper<0, _Equal>
1671  {
1672  public:
1673  typedef _Key key_type;
1674  typedef _Value value_type;
1675  typedef _Equal key_equal;
1676  typedef std::size_t size_type;
1677  typedef std::ptrdiff_t difference_type;
1678 
1679  using __traits_type = _Traits;
1680  using __hash_cached = typename __traits_type::__hash_cached;
1681 
1682  using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1683  _Hash, _RangeHash, _Unused,
1684  __hash_cached::value>;
1685 
1686  using __hash_code = typename __hash_code_base::__hash_code;
1687 
1688  private:
1689  using _EqualEBO = _Hashtable_ebo_helper<0, _Equal>;
1690 
1691  static bool
1692  _S_equals(__hash_code, const _Hash_node_code_cache<false>&)
1693  { return true; }
1694 
1695  static bool
1696  _S_node_equals(const _Hash_node_code_cache<false>&,
1697  const _Hash_node_code_cache<false>&)
1698  { return true; }
1699 
1700  static bool
1701  _S_equals(__hash_code __c, const _Hash_node_code_cache<true>& __n)
1702  { return __c == __n._M_hash_code; }
1703 
1704  static bool
1705  _S_node_equals(const _Hash_node_code_cache<true>& __lhn,
1706  const _Hash_node_code_cache<true>& __rhn)
1707  { return __lhn._M_hash_code == __rhn._M_hash_code; }
1708 
1709  protected:
1710  _Hashtable_base() = default;
1711 
1712  _Hashtable_base(const _Hash& __hash, const _Equal& __eq)
1713  : __hash_code_base(__hash), _EqualEBO(__eq)
1714  { }
1715 
1716  bool
1717  _M_key_equals(const _Key& __k,
1718  const _Hash_node_value<_Value,
1719  __hash_cached::value>& __n) const
1720  {
1721  static_assert(__is_invocable<const _Equal&, const _Key&, const _Key&>{},
1722  "key equality predicate must be invocable with two arguments of "
1723  "key type");
1724  return _M_eq()(__k, _ExtractKey{}(__n._M_v()));
1725  }
1726 
1727  template<typename _Kt>
1728  bool
1729  _M_key_equals_tr(const _Kt& __k,
1730  const _Hash_node_value<_Value,
1731  __hash_cached::value>& __n) const
1732  {
1733  static_assert(
1734  __is_invocable<const _Equal&, const _Kt&, const _Key&>{},
1735  "key equality predicate must be invocable with two arguments of "
1736  "key type");
1737  return _M_eq()(__k, _ExtractKey{}(__n._M_v()));
1738  }
1739 
1740  bool
1741  _M_equals(const _Key& __k, __hash_code __c,
1742  const _Hash_node_value<_Value, __hash_cached::value>& __n) const
1743  { return _S_equals(__c, __n) && _M_key_equals(__k, __n); }
1744 
1745  template<typename _Kt>
1746  bool
1747  _M_equals_tr(const _Kt& __k, __hash_code __c,
1748  const _Hash_node_value<_Value,
1749  __hash_cached::value>& __n) const
1750  { return _S_equals(__c, __n) && _M_key_equals_tr(__k, __n); }
1751 
1752  bool
1753  _M_node_equals(
1754  const _Hash_node_value<_Value, __hash_cached::value>& __lhn,
1755  const _Hash_node_value<_Value, __hash_cached::value>& __rhn) const
1756  {
1757  return _S_node_equals(__lhn, __rhn)
1758  && _M_key_equals(_ExtractKey{}(__lhn._M_v()), __rhn);
1759  }
1760 
1761  void
1762  _M_swap(_Hashtable_base& __x)
1763  {
1764  __hash_code_base::_M_swap(__x);
1765  std::swap(_EqualEBO::_M_get(), __x._EqualEBO::_M_get());
1766  }
1767 
1768  const _Equal&
1769  _M_eq() const { return _EqualEBO::_M_cget(); }
1770  };
1771 
1772  /**
1773  * Primary class template _Equality.
1774  *
1775  * This is for implementing equality comparison for unordered
1776  * containers, per N3068, by John Lakos and Pablo Halpern.
1777  * Algorithmically, we follow closely the reference implementations
1778  * therein.
1779  */
1780  template<typename _Key, typename _Value, typename _Alloc,
1781  typename _ExtractKey, typename _Equal,
1782  typename _Hash, typename _RangeHash, typename _Unused,
1783  typename _RehashPolicy, typename _Traits,
1784  bool _Unique_keys = _Traits::__unique_keys::value>
1785  struct _Equality;
1786 
1787  /// unordered_map and unordered_set specializations.
1788  template<typename _Key, typename _Value, typename _Alloc,
1789  typename _ExtractKey, typename _Equal,
1790  typename _Hash, typename _RangeHash, typename _Unused,
1791  typename _RehashPolicy, typename _Traits>
1792  struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1793  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>
1794  {
1795  using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1796  _Hash, _RangeHash, _Unused,
1797  _RehashPolicy, _Traits>;
1798 
1799  bool
1800  _M_equal(const __hashtable&) const;
1801  };
1802 
1803  template<typename _Key, typename _Value, typename _Alloc,
1804  typename _ExtractKey, typename _Equal,
1805  typename _Hash, typename _RangeHash, typename _Unused,
1806  typename _RehashPolicy, typename _Traits>
1807  bool
1808  _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1809  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
1810  _M_equal(const __hashtable& __other) const
1811  {
1812  using __node_type = typename __hashtable::__node_type;
1813  const __hashtable* __this = static_cast<const __hashtable*>(this);
1814  if (__this->size() != __other.size())
1815  return false;
1816 
1817  for (auto __itx = __this->begin(); __itx != __this->end(); ++__itx)
1818  {
1819  std::size_t __ybkt = __other._M_bucket_index(*__itx._M_cur);
1820  auto __prev_n = __other._M_buckets[__ybkt];
1821  if (!__prev_n)
1822  return false;
1823 
1824  for (__node_type* __n = static_cast<__node_type*>(__prev_n->_M_nxt);;
1825  __n = __n->_M_next())
1826  {
1827  if (__n->_M_v() == *__itx)
1828  break;
1829 
1830  if (!__n->_M_nxt
1831  || __other._M_bucket_index(*__n->_M_next()) != __ybkt)
1832  return false;
1833  }
1834  }
1835 
1836  return true;
1837  }
1838 
1839  /// unordered_multiset and unordered_multimap specializations.
1840  template<typename _Key, typename _Value, typename _Alloc,
1841  typename _ExtractKey, typename _Equal,
1842  typename _Hash, typename _RangeHash, typename _Unused,
1843  typename _RehashPolicy, typename _Traits>
1844  struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1845  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
1846  {
1847  using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1848  _Hash, _RangeHash, _Unused,
1849  _RehashPolicy, _Traits>;
1850 
1851  bool
1852  _M_equal(const __hashtable&) const;
1853  };
1854 
1855  template<typename _Key, typename _Value, typename _Alloc,
1856  typename _ExtractKey, typename _Equal,
1857  typename _Hash, typename _RangeHash, typename _Unused,
1858  typename _RehashPolicy, typename _Traits>
1859  bool
1860  _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1861  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>::
1862  _M_equal(const __hashtable& __other) const
1863  {
1864  using __node_type = typename __hashtable::__node_type;
1865  const __hashtable* __this = static_cast<const __hashtable*>(this);
1866  if (__this->size() != __other.size())
1867  return false;
1868 
1869  for (auto __itx = __this->begin(); __itx != __this->end();)
1870  {
1871  std::size_t __x_count = 1;
1872  auto __itx_end = __itx;
1873  for (++__itx_end; __itx_end != __this->end()
1874  && __this->key_eq()(_ExtractKey{}(*__itx),
1875  _ExtractKey{}(*__itx_end));
1876  ++__itx_end)
1877  ++__x_count;
1878 
1879  std::size_t __ybkt = __other._M_bucket_index(*__itx._M_cur);
1880  auto __y_prev_n = __other._M_buckets[__ybkt];
1881  if (!__y_prev_n)
1882  return false;
1883 
1884  __node_type* __y_n = static_cast<__node_type*>(__y_prev_n->_M_nxt);
1885  for (;;)
1886  {
1887  if (__this->key_eq()(_ExtractKey{}(__y_n->_M_v()),
1888  _ExtractKey{}(*__itx)))
1889  break;
1890 
1891  auto __y_ref_n = __y_n;
1892  for (__y_n = __y_n->_M_next(); __y_n; __y_n = __y_n->_M_next())
1893  if (!__other._M_node_equals(*__y_ref_n, *__y_n))
1894  break;
1895 
1896  if (!__y_n || __other._M_bucket_index(*__y_n) != __ybkt)
1897  return false;
1898  }
1899 
1900  typename __hashtable::const_iterator __ity(__y_n);
1901  for (auto __ity_end = __ity; __ity_end != __other.end(); ++__ity_end)
1902  if (--__x_count == 0)
1903  break;
1904 
1905  if (__x_count != 0)
1906  return false;
1907 
1908  if (!std::is_permutation(__itx, __itx_end, __ity))
1909  return false;
1910 
1911  __itx = __itx_end;
1912  }
1913  return true;
1914  }
1915 
1916  /**
1917  * This type deals with all allocation and keeps an allocator instance
1918  * through inheritance to benefit from EBO when possible.
1919  */
1920  template<typename _NodeAlloc>
1921  struct _Hashtable_alloc : private _Hashtable_ebo_helper<0, _NodeAlloc>
1922  {
1923  private:
1924  using __ebo_node_alloc = _Hashtable_ebo_helper<0, _NodeAlloc>;
1925 
1926  template<typename>
1927  struct __get_value_type;
1928  template<typename _Val, bool _Cache_hash_code>
1929  struct __get_value_type<_Hash_node<_Val, _Cache_hash_code>>
1930  { using type = _Val; };
1931 
1932  public:
1933  using __node_type = typename _NodeAlloc::value_type;
1934  using __node_alloc_type = _NodeAlloc;
1935  // Use __gnu_cxx to benefit from _S_always_equal and al.
1936  using __node_alloc_traits = __gnu_cxx::__alloc_traits<__node_alloc_type>;
1937 
1938  using __value_alloc_traits = typename __node_alloc_traits::template
1939  rebind_traits<typename __get_value_type<__node_type>::type>;
1940 
1941  using __node_ptr = __node_type*;
1942  using __node_base = _Hash_node_base;
1943  using __node_base_ptr = __node_base*;
1944  using __buckets_alloc_type =
1945  __alloc_rebind<__node_alloc_type, __node_base_ptr>;
1946  using __buckets_alloc_traits = std::allocator_traits<__buckets_alloc_type>;
1947  using __buckets_ptr = __node_base_ptr*;
1948 
1949  _Hashtable_alloc() = default;
1950  _Hashtable_alloc(const _Hashtable_alloc&) = default;
1951  _Hashtable_alloc(_Hashtable_alloc&&) = default;
1952 
1953  template<typename _Alloc>
1954  _Hashtable_alloc(_Alloc&& __a)
1955  : __ebo_node_alloc(std::forward<_Alloc>(__a))
1956  { }
1957 
1958  __node_alloc_type&
1959  _M_node_allocator()
1960  { return __ebo_node_alloc::_M_get(); }
1961 
1962  const __node_alloc_type&
1963  _M_node_allocator() const
1964  { return __ebo_node_alloc::_M_cget(); }
1965 
1966  // Allocate a node and construct an element within it.
1967  template<typename... _Args>
1968  __node_ptr
1969  _M_allocate_node(_Args&&... __args);
1970 
1971  // Destroy the element within a node and deallocate the node.
1972  void
1973  _M_deallocate_node(__node_ptr __n);
1974 
1975  // Deallocate a node.
1976  void
1977  _M_deallocate_node_ptr(__node_ptr __n);
1978 
1979  // Deallocate the linked list of nodes pointed to by __n.
1980  // The elements within the nodes are destroyed.
1981  void
1982  _M_deallocate_nodes(__node_ptr __n);
1983 
1984  __buckets_ptr
1985  _M_allocate_buckets(std::size_t __bkt_count);
1986 
1987  void
1988  _M_deallocate_buckets(__buckets_ptr, std::size_t __bkt_count);
1989  };
1990 
1991  // Definitions of class template _Hashtable_alloc's out-of-line member
1992  // functions.
1993  template<typename _NodeAlloc>
1994  template<typename... _Args>
1995  auto
1996  _Hashtable_alloc<_NodeAlloc>::_M_allocate_node(_Args&&... __args)
1997  -> __node_ptr
1998  {
1999  auto __nptr = __node_alloc_traits::allocate(_M_node_allocator(), 1);
2000  __node_ptr __n = std::__to_address(__nptr);
2001  __try
2002  {
2003  ::new ((void*)__n) __node_type;
2004  __node_alloc_traits::construct(_M_node_allocator(),
2005  __n->_M_valptr(),
2006  std::forward<_Args>(__args)...);
2007  return __n;
2008  }
2009  __catch(...)
2010  {
2011  __node_alloc_traits::deallocate(_M_node_allocator(), __nptr, 1);
2012  __throw_exception_again;
2013  }
2014  }
2015 
2016  template<typename _NodeAlloc>
2017  void
2018  _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node(__node_ptr __n)
2019  {
2020  __node_alloc_traits::destroy(_M_node_allocator(), __n->_M_valptr());
2021  _M_deallocate_node_ptr(__n);
2022  }
2023 
2024  template<typename _NodeAlloc>
2025  void
2026  _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node_ptr(__node_ptr __n)
2027  {
2028  typedef typename __node_alloc_traits::pointer _Ptr;
2029  auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__n);
2030  __n->~__node_type();
2031  __node_alloc_traits::deallocate(_M_node_allocator(), __ptr, 1);
2032  }
2033 
2034  template<typename _NodeAlloc>
2035  void
2036  _Hashtable_alloc<_NodeAlloc>::_M_deallocate_nodes(__node_ptr __n)
2037  {
2038  while (__n)
2039  {
2040  __node_ptr __tmp = __n;
2041  __n = __n->_M_next();
2042  _M_deallocate_node(__tmp);
2043  }
2044  }
2045 
2046  template<typename _NodeAlloc>
2047  auto
2048  _Hashtable_alloc<_NodeAlloc>::_M_allocate_buckets(std::size_t __bkt_count)
2049  -> __buckets_ptr
2050  {
2051  __buckets_alloc_type __alloc(_M_node_allocator());
2052 
2053  auto __ptr = __buckets_alloc_traits::allocate(__alloc, __bkt_count);
2054  __buckets_ptr __p = std::__to_address(__ptr);
2055  __builtin_memset(__p, 0, __bkt_count * sizeof(__node_base_ptr));
2056  return __p;
2057  }
2058 
2059  template<typename _NodeAlloc>
2060  void
2061  _Hashtable_alloc<_NodeAlloc>::
2062  _M_deallocate_buckets(__buckets_ptr __bkts,
2063  std::size_t __bkt_count)
2064  {
2065  typedef typename __buckets_alloc_traits::pointer _Ptr;
2066  auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__bkts);
2067  __buckets_alloc_type __alloc(_M_node_allocator());
2068  __buckets_alloc_traits::deallocate(__alloc, __ptr, __bkt_count);
2069  }
2070 
2071  ///@} hashtable-detail
2072 } // namespace __detail
2073 /// @endcond
2074 _GLIBCXX_END_NAMESPACE_VERSION
2075 } // namespace std
2076 
2077 #endif // _HASHTABLE_POLICY_H
constexpr iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
Primary class template, tuple.
Definition: tuple:58
constexpr _Iterator __base(_Iterator __it)
Marking input iterators.
constexpr iterator_traits< _Iter >::iterator_category __iterator_category(const _Iter &)
constexpr tuple< _Elements &&... > forward_as_tuple(_Elements &&... __args) noexcept
Create a tuple of lvalue or rvalue references to the arguments.
Definition: tuple:1999
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
Definition: move.h:70
is_constructible
Definition: type_traits:1045
Definition: simd.h:281
Uniform interface to all allocator types.
Struct holding two objects of arbitrary type.
Define a member typedef type only if a boolean constant is true.
Definition: type_traits:106
Forward iterators support a superset of input iterator operations.
constexpr complex< _Tp > operator*(const complex< _Tp > &__x, const complex< _Tp > &__y)
Return new complex value x times y.
Definition: complex:395
constexpr piecewise_construct_t piecewise_construct
Tag for piecewise construction of std::pair objects.
Definition: stl_pair.h:83
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:82
Uniform interface to C++98 and C++11 allocators.
Traits class for iterators.
ISO C++ entities toplevel namespace is std.
Uniform interface to all pointer-like types.
Definition: ptr_traits.h:184
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:85
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:97
is_empty
Definition: type_traits:842
__numeric_traits_integer< _Tp > __int_traits
Convenience alias for __numeric_traits<integer-type>.