libstdc++
hashtable_policy.h
Go to the documentation of this file.
1 // Internal policy header for unordered_set and unordered_map -*- C++ -*-
2 
3 // Copyright (C) 2010-2021 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/stl_algobase.h> // for std::min, std::is_permutation.
36 #include <ext/numeric_traits.h> // for __gnu_cxx::__int_traits
37 
38 namespace std _GLIBCXX_VISIBILITY(default)
39 {
40 _GLIBCXX_BEGIN_NAMESPACE_VERSION
41 /// @cond undocumented
42 
43  template<typename _Key, typename _Value, typename _Alloc,
44  typename _ExtractKey, typename _Equal,
45  typename _Hash, typename _RangeHash, typename _Unused,
46  typename _RehashPolicy, typename _Traits>
47  class _Hashtable;
48 
49 namespace __detail
50 {
51  /**
52  * @defgroup hashtable-detail Base and Implementation Classes
53  * @ingroup unordered_associative_containers
54  * @{
55  */
56  template<typename _Key, typename _Value, typename _ExtractKey,
57  typename _Equal, typename _Hash, typename _RangeHash,
58  typename _Unused, typename _Traits>
59  struct _Hashtable_base;
60 
61  // Helper function: return distance(first, last) for forward
62  // iterators, or 0/1 for input iterators.
63  template<typename _Iterator>
65  __distance_fw(_Iterator __first, _Iterator __last,
67  { return __first != __last ? 1 : 0; }
68 
69  template<typename _Iterator>
71  __distance_fw(_Iterator __first, _Iterator __last,
73  { return std::distance(__first, __last); }
74 
75  template<typename _Iterator>
77  __distance_fw(_Iterator __first, _Iterator __last)
78  { return __distance_fw(__first, __last,
79  std::__iterator_category(__first)); }
80 
81  struct _Identity
82  {
83  template<typename _Tp>
84  _Tp&&
85  operator()(_Tp&& __x) const noexcept
86  { return std::forward<_Tp>(__x); }
87  };
88 
89  struct _Select1st
90  {
91  template<typename _Pair>
92  struct __1st_type;
93 
94  template<typename _Tp, typename _Up>
95  struct __1st_type<pair<_Tp, _Up>>
96  { using type = _Tp; };
97 
98  template<typename _Tp, typename _Up>
99  struct __1st_type<const pair<_Tp, _Up>>
100  { using type = const _Tp; };
101 
102  template<typename _Pair>
103  struct __1st_type<_Pair&>
104  { using type = typename __1st_type<_Pair>::type&; };
105 
106  template<typename _Tp>
107  typename __1st_type<_Tp>::type&&
108  operator()(_Tp&& __x) const noexcept
109  { return std::forward<_Tp>(__x).first; }
110  };
111 
112  template<typename _ExKey>
113  struct _NodeBuilder;
114 
115  template<>
116  struct _NodeBuilder<_Select1st>
117  {
118  template<typename _Kt, typename _Arg, typename _NodeGenerator>
119  static auto
120  _S_build(_Kt&& __k, _Arg&& __arg, const _NodeGenerator& __node_gen)
121  -> typename _NodeGenerator::__node_type*
122  {
123  return __node_gen(std::forward<_Kt>(__k),
124  std::forward<_Arg>(__arg).second);
125  }
126  };
127 
128  template<>
129  struct _NodeBuilder<_Identity>
130  {
131  template<typename _Kt, typename _Arg, typename _NodeGenerator>
132  static auto
133  _S_build(_Kt&& __k, _Arg&&, const _NodeGenerator& __node_gen)
134  -> typename _NodeGenerator::__node_type*
135  { return __node_gen(std::forward<_Kt>(__k)); }
136  };
137 
138  template<typename _NodeAlloc>
139  struct _Hashtable_alloc;
140 
141  // Functor recycling a pool of nodes and using allocation once the pool is
142  // empty.
143  template<typename _NodeAlloc>
144  struct _ReuseOrAllocNode
145  {
146  private:
147  using __node_alloc_type = _NodeAlloc;
148  using __hashtable_alloc = _Hashtable_alloc<__node_alloc_type>;
149  using __node_alloc_traits =
150  typename __hashtable_alloc::__node_alloc_traits;
151 
152  public:
153  using __node_type = typename __hashtable_alloc::__node_type;
154 
155  _ReuseOrAllocNode(__node_type* __nodes, __hashtable_alloc& __h)
156  : _M_nodes(__nodes), _M_h(__h) { }
157  _ReuseOrAllocNode(const _ReuseOrAllocNode&) = delete;
158 
159  ~_ReuseOrAllocNode()
160  { _M_h._M_deallocate_nodes(_M_nodes); }
161 
162  template<typename... _Args>
163  __node_type*
164  operator()(_Args&&... __args) const
165  {
166  if (_M_nodes)
167  {
168  __node_type* __node = _M_nodes;
169  _M_nodes = _M_nodes->_M_next();
170  __node->_M_nxt = nullptr;
171  auto& __a = _M_h._M_node_allocator();
172  __node_alloc_traits::destroy(__a, __node->_M_valptr());
173  __try
174  {
175  __node_alloc_traits::construct(__a, __node->_M_valptr(),
176  std::forward<_Args>(__args)...);
177  }
178  __catch(...)
179  {
180  _M_h._M_deallocate_node_ptr(__node);
181  __throw_exception_again;
182  }
183  return __node;
184  }
185  return _M_h._M_allocate_node(std::forward<_Args>(__args)...);
186  }
187 
188  private:
189  mutable __node_type* _M_nodes;
190  __hashtable_alloc& _M_h;
191  };
192 
193  // Functor similar to the previous one but without any pool of nodes to
194  // recycle.
195  template<typename _NodeAlloc>
196  struct _AllocNode
197  {
198  private:
199  using __hashtable_alloc = _Hashtable_alloc<_NodeAlloc>;
200 
201  public:
202  using __node_type = typename __hashtable_alloc::__node_type;
203 
204  _AllocNode(__hashtable_alloc& __h)
205  : _M_h(__h) { }
206 
207  template<typename... _Args>
208  __node_type*
209  operator()(_Args&&... __args) const
210  { return _M_h._M_allocate_node(std::forward<_Args>(__args)...); }
211 
212  private:
213  __hashtable_alloc& _M_h;
214  };
215 
216  // Auxiliary types used for all instantiations of _Hashtable nodes
217  // and iterators.
218 
219  /**
220  * struct _Hashtable_traits
221  *
222  * Important traits for hash tables.
223  *
224  * @tparam _Cache_hash_code Boolean value. True if the value of
225  * the hash function is stored along with the value. This is a
226  * time-space tradeoff. Storing it may improve lookup speed by
227  * reducing the number of times we need to call the _Hash or _Equal
228  * functors.
229  *
230  * @tparam _Constant_iterators Boolean value. True if iterator and
231  * const_iterator are both constant iterator types. This is true
232  * for unordered_set and unordered_multiset, false for
233  * unordered_map and unordered_multimap.
234  *
235  * @tparam _Unique_keys Boolean value. True if the return value
236  * of _Hashtable::count(k) is always at most one, false if it may
237  * be an arbitrary number. This is true for unordered_set and
238  * unordered_map, false for unordered_multiset and
239  * unordered_multimap.
240  */
241  template<bool _Cache_hash_code, bool _Constant_iterators, bool _Unique_keys>
242  struct _Hashtable_traits
243  {
244  using __hash_cached = __bool_constant<_Cache_hash_code>;
245  using __constant_iterators = __bool_constant<_Constant_iterators>;
246  using __unique_keys = __bool_constant<_Unique_keys>;
247  };
248 
249  /**
250  * struct _Hash_node_base
251  *
252  * Nodes, used to wrap elements stored in the hash table. A policy
253  * template parameter of class template _Hashtable controls whether
254  * nodes also store a hash code. In some cases (e.g. strings) this
255  * may be a performance win.
256  */
257  struct _Hash_node_base
258  {
259  _Hash_node_base* _M_nxt;
260 
261  _Hash_node_base() noexcept : _M_nxt() { }
262 
263  _Hash_node_base(_Hash_node_base* __next) noexcept : _M_nxt(__next) { }
264  };
265 
266  /**
267  * struct _Hash_node_value_base
268  *
269  * Node type with the value to store.
270  */
271  template<typename _Value>
272  struct _Hash_node_value_base
273  {
274  typedef _Value value_type;
275 
276  __gnu_cxx::__aligned_buffer<_Value> _M_storage;
277 
278  _Value*
279  _M_valptr() noexcept
280  { return _M_storage._M_ptr(); }
281 
282  const _Value*
283  _M_valptr() const noexcept
284  { return _M_storage._M_ptr(); }
285 
286  _Value&
287  _M_v() noexcept
288  { return *_M_valptr(); }
289 
290  const _Value&
291  _M_v() const noexcept
292  { return *_M_valptr(); }
293  };
294 
295  /**
296  * Primary template struct _Hash_node_code_cache.
297  */
298  template<bool _Cache_hash_code>
299  struct _Hash_node_code_cache
300  { };
301 
302  /**
303  * Specialization for node with cache, struct _Hash_node_code_cache.
304  */
305  template<>
306  struct _Hash_node_code_cache<true>
307  { std::size_t _M_hash_code; };
308 
309  template<typename _Value, bool _Cache_hash_code>
310  struct _Hash_node_value
311  : _Hash_node_value_base<_Value>
312  , _Hash_node_code_cache<_Cache_hash_code>
313  { };
314 
315  /**
316  * Primary template struct _Hash_node.
317  */
318  template<typename _Value, bool _Cache_hash_code>
319  struct _Hash_node
320  : _Hash_node_base
321  , _Hash_node_value<_Value, _Cache_hash_code>
322  {
323  _Hash_node*
324  _M_next() const noexcept
325  { return static_cast<_Hash_node*>(this->_M_nxt); }
326  };
327 
328  /// Base class for node iterators.
329  template<typename _Value, bool _Cache_hash_code>
330  struct _Node_iterator_base
331  {
332  using __node_type = _Hash_node<_Value, _Cache_hash_code>;
333 
334  __node_type* _M_cur;
335 
336  _Node_iterator_base() : _M_cur(nullptr) { }
337  _Node_iterator_base(__node_type* __p) noexcept
338  : _M_cur(__p) { }
339 
340  void
341  _M_incr() noexcept
342  { _M_cur = _M_cur->_M_next(); }
343 
344  friend bool
345  operator==(const _Node_iterator_base& __x, const _Node_iterator_base& __y)
346  noexcept
347  { return __x._M_cur == __y._M_cur; }
348 
349 #if __cpp_impl_three_way_comparison < 201907L
350  friend bool
351  operator!=(const _Node_iterator_base& __x, const _Node_iterator_base& __y)
352  noexcept
353  { return __x._M_cur != __y._M_cur; }
354 #endif
355  };
356 
357  /// Node iterators, used to iterate through all the hashtable.
358  template<typename _Value, bool __constant_iterators, bool __cache>
359  struct _Node_iterator
360  : public _Node_iterator_base<_Value, __cache>
361  {
362  private:
363  using __base_type = _Node_iterator_base<_Value, __cache>;
364  using __node_type = typename __base_type::__node_type;
365 
366  public:
367  using value_type = _Value;
368  using difference_type = std::ptrdiff_t;
369  using iterator_category = std::forward_iterator_tag;
370 
371  using pointer = __conditional_t<__constant_iterators,
372  const value_type*, value_type*>;
373 
374  using reference = __conditional_t<__constant_iterators,
375  const value_type&, value_type&>;
376 
377  _Node_iterator() = default;
378 
379  explicit
380  _Node_iterator(__node_type* __p) noexcept
381  : __base_type(__p) { }
382 
383  reference
384  operator*() const noexcept
385  { return this->_M_cur->_M_v(); }
386 
387  pointer
388  operator->() const noexcept
389  { return this->_M_cur->_M_valptr(); }
390 
391  _Node_iterator&
392  operator++() noexcept
393  {
394  this->_M_incr();
395  return *this;
396  }
397 
398  _Node_iterator
399  operator++(int) noexcept
400  {
401  _Node_iterator __tmp(*this);
402  this->_M_incr();
403  return __tmp;
404  }
405  };
406 
407  /// Node const_iterators, used to iterate through all the hashtable.
408  template<typename _Value, bool __constant_iterators, bool __cache>
409  struct _Node_const_iterator
410  : public _Node_iterator_base<_Value, __cache>
411  {
412  private:
413  using __base_type = _Node_iterator_base<_Value, __cache>;
414  using __node_type = typename __base_type::__node_type;
415 
416  public:
417  typedef _Value value_type;
418  typedef std::ptrdiff_t difference_type;
419  typedef std::forward_iterator_tag iterator_category;
420 
421  typedef const value_type* pointer;
422  typedef const value_type& reference;
423 
424  _Node_const_iterator() = default;
425 
426  explicit
427  _Node_const_iterator(__node_type* __p) noexcept
428  : __base_type(__p) { }
429 
430  _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators,
431  __cache>& __x) noexcept
432  : __base_type(__x._M_cur) { }
433 
434  reference
435  operator*() const noexcept
436  { return this->_M_cur->_M_v(); }
437 
438  pointer
439  operator->() const noexcept
440  { return this->_M_cur->_M_valptr(); }
441 
442  _Node_const_iterator&
443  operator++() noexcept
444  {
445  this->_M_incr();
446  return *this;
447  }
448 
449  _Node_const_iterator
450  operator++(int) noexcept
451  {
452  _Node_const_iterator __tmp(*this);
453  this->_M_incr();
454  return __tmp;
455  }
456  };
457 
458  // Many of class template _Hashtable's template parameters are policy
459  // classes. These are defaults for the policies.
460 
461  /// Default range hashing function: use division to fold a large number
462  /// into the range [0, N).
463  struct _Mod_range_hashing
464  {
465  typedef std::size_t first_argument_type;
466  typedef std::size_t second_argument_type;
467  typedef std::size_t result_type;
468 
469  result_type
470  operator()(first_argument_type __num,
471  second_argument_type __den) const noexcept
472  { return __num % __den; }
473  };
474 
475  /// Default ranged hash function H. In principle it should be a
476  /// function object composed from objects of type H1 and H2 such that
477  /// h(k, N) = h2(h1(k), N), but that would mean making extra copies of
478  /// h1 and h2. So instead we'll just use a tag to tell class template
479  /// hashtable to do that composition.
480  struct _Default_ranged_hash { };
481 
482  /// Default value for rehash policy. Bucket size is (usually) the
483  /// smallest prime that keeps the load factor small enough.
484  struct _Prime_rehash_policy
485  {
486  using __has_load_factor = true_type;
487 
488  _Prime_rehash_policy(float __z = 1.0) noexcept
489  : _M_max_load_factor(__z), _M_next_resize(0) { }
490 
491  float
492  max_load_factor() const noexcept
493  { return _M_max_load_factor; }
494 
495  // Return a bucket size no smaller than n.
496  std::size_t
497  _M_next_bkt(std::size_t __n) const;
498 
499  // Return a bucket count appropriate for n elements
500  std::size_t
501  _M_bkt_for_elements(std::size_t __n) const
502  { return __builtin_ceil(__n / (double)_M_max_load_factor); }
503 
504  // __n_bkt is current bucket count, __n_elt is current element count,
505  // and __n_ins is number of elements to be inserted. Do we need to
506  // increase bucket count? If so, return make_pair(true, n), where n
507  // is the new bucket count. If not, return make_pair(false, 0).
509  _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
510  std::size_t __n_ins) const;
511 
512  typedef std::size_t _State;
513 
514  _State
515  _M_state() const
516  { return _M_next_resize; }
517 
518  void
519  _M_reset() noexcept
520  { _M_next_resize = 0; }
521 
522  void
523  _M_reset(_State __state)
524  { _M_next_resize = __state; }
525 
526  static const std::size_t _S_growth_factor = 2;
527 
528  float _M_max_load_factor;
529  mutable std::size_t _M_next_resize;
530  };
531 
532  /// Range hashing function assuming that second arg is a power of 2.
533  struct _Mask_range_hashing
534  {
535  typedef std::size_t first_argument_type;
536  typedef std::size_t second_argument_type;
537  typedef std::size_t result_type;
538 
539  result_type
540  operator()(first_argument_type __num,
541  second_argument_type __den) const noexcept
542  { return __num & (__den - 1); }
543  };
544 
545  /// Compute closest power of 2 not less than __n
546  inline std::size_t
547  __clp2(std::size_t __n) noexcept
548  {
550  // Equivalent to return __n ? std::bit_ceil(__n) : 0;
551  if (__n < 2)
552  return __n;
553  const unsigned __lz = sizeof(size_t) > sizeof(long)
554  ? __builtin_clzll(__n - 1ull)
555  : __builtin_clzl(__n - 1ul);
556  // Doing two shifts avoids undefined behaviour when __lz == 0.
557  return (size_t(1) << (__int_traits<size_t>::__digits - __lz - 1)) << 1;
558  }
559 
560  /// Rehash policy providing power of 2 bucket numbers. Avoids modulo
561  /// operations.
562  struct _Power2_rehash_policy
563  {
564  using __has_load_factor = true_type;
565 
566  _Power2_rehash_policy(float __z = 1.0) noexcept
567  : _M_max_load_factor(__z), _M_next_resize(0) { }
568 
569  float
570  max_load_factor() const noexcept
571  { return _M_max_load_factor; }
572 
573  // Return a bucket size no smaller than n (as long as n is not above the
574  // highest power of 2).
575  std::size_t
576  _M_next_bkt(std::size_t __n) noexcept
577  {
578  if (__n == 0)
579  // Special case on container 1st initialization with 0 bucket count
580  // hint. We keep _M_next_resize to 0 to make sure that next time we
581  // want to add an element allocation will take place.
582  return 1;
583 
584  const auto __max_width = std::min<size_t>(sizeof(size_t), 8);
585  const auto __max_bkt = size_t(1) << (__max_width * __CHAR_BIT__ - 1);
586  std::size_t __res = __clp2(__n);
587 
588  if (__res == 0)
589  __res = __max_bkt;
590  else if (__res == 1)
591  // If __res is 1 we force it to 2 to make sure there will be an
592  // allocation so that nothing need to be stored in the initial
593  // single bucket
594  __res = 2;
595 
596  if (__res == __max_bkt)
597  // Set next resize to the max value so that we never try to rehash again
598  // as we already reach the biggest possible bucket number.
599  // Note that it might result in max_load_factor not being respected.
600  _M_next_resize = size_t(-1);
601  else
602  _M_next_resize
603  = __builtin_floor(__res * (double)_M_max_load_factor);
604 
605  return __res;
606  }
607 
608  // Return a bucket count appropriate for n elements
609  std::size_t
610  _M_bkt_for_elements(std::size_t __n) const noexcept
611  { return __builtin_ceil(__n / (double)_M_max_load_factor); }
612 
613  // __n_bkt is current bucket count, __n_elt is current element count,
614  // and __n_ins is number of elements to be inserted. Do we need to
615  // increase bucket count? If so, return make_pair(true, n), where n
616  // is the new bucket count. If not, return make_pair(false, 0).
618  _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
619  std::size_t __n_ins) noexcept
620  {
621  if (__n_elt + __n_ins > _M_next_resize)
622  {
623  // If _M_next_resize is 0 it means that we have nothing allocated so
624  // far and that we start inserting elements. In this case we start
625  // with an initial bucket size of 11.
626  double __min_bkts
627  = std::max<std::size_t>(__n_elt + __n_ins, _M_next_resize ? 0 : 11)
628  / (double)_M_max_load_factor;
629  if (__min_bkts >= __n_bkt)
630  return { true,
631  _M_next_bkt(std::max<std::size_t>(__builtin_floor(__min_bkts) + 1,
632  __n_bkt * _S_growth_factor)) };
633 
634  _M_next_resize
635  = __builtin_floor(__n_bkt * (double)_M_max_load_factor);
636  return { false, 0 };
637  }
638  else
639  return { false, 0 };
640  }
641 
642  typedef std::size_t _State;
643 
644  _State
645  _M_state() const noexcept
646  { return _M_next_resize; }
647 
648  void
649  _M_reset() noexcept
650  { _M_next_resize = 0; }
651 
652  void
653  _M_reset(_State __state) noexcept
654  { _M_next_resize = __state; }
655 
656  static const std::size_t _S_growth_factor = 2;
657 
658  float _M_max_load_factor;
659  std::size_t _M_next_resize;
660  };
661 
662  // Base classes for std::_Hashtable. We define these base classes
663  // because in some cases we want to do different things depending on
664  // the value of a policy class. In some cases the policy class
665  // affects which member functions and nested typedefs are defined;
666  // we handle that by specializing base class templates. Several of
667  // the base class templates need to access other members of class
668  // template _Hashtable, so we use a variant of the "Curiously
669  // Recurring Template Pattern" (CRTP) technique.
670 
671  /**
672  * Primary class template _Map_base.
673  *
674  * If the hashtable has a value type of the form pair<const T1, T2> and
675  * a key extraction policy (_ExtractKey) that returns the first part
676  * of the pair, the hashtable gets a mapped_type typedef. If it
677  * satisfies those criteria and also has unique keys, then it also
678  * gets an operator[].
679  */
680  template<typename _Key, typename _Value, typename _Alloc,
681  typename _ExtractKey, typename _Equal,
682  typename _Hash, typename _RangeHash, typename _Unused,
683  typename _RehashPolicy, typename _Traits,
684  bool _Unique_keys = _Traits::__unique_keys::value>
685  struct _Map_base { };
686 
687  /// Partial specialization, __unique_keys set to false, std::pair value type.
688  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
689  typename _Hash, typename _RangeHash, typename _Unused,
690  typename _RehashPolicy, typename _Traits>
691  struct _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
692  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
693  {
694  using mapped_type = _Val;
695  };
696 
697  /// Partial specialization, __unique_keys set to true.
698  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
699  typename _Hash, typename _RangeHash, typename _Unused,
700  typename _RehashPolicy, typename _Traits>
701  struct _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
702  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>
703  {
704  private:
705  using __hashtable_base = _Hashtable_base<_Key, pair<const _Key, _Val>,
706  _Select1st, _Equal, _Hash,
707  _RangeHash, _Unused,
708  _Traits>;
709 
710  using __hashtable = _Hashtable<_Key, pair<const _Key, _Val>, _Alloc,
711  _Select1st, _Equal, _Hash, _RangeHash,
712  _Unused, _RehashPolicy, _Traits>;
713 
714  using __hash_code = typename __hashtable_base::__hash_code;
715 
716  public:
717  using key_type = typename __hashtable_base::key_type;
718  using mapped_type = _Val;
719 
720  mapped_type&
721  operator[](const key_type& __k);
722 
723  mapped_type&
724  operator[](key_type&& __k);
725 
726  // _GLIBCXX_RESOLVE_LIB_DEFECTS
727  // DR 761. unordered_map needs an at() member function.
728  mapped_type&
729  at(const key_type& __k)
730  {
731  auto __ite = static_cast<__hashtable*>(this)->find(__k);
732  if (!__ite._M_cur)
733  __throw_out_of_range(__N("unordered_map::at"));
734  return __ite->second;
735  }
736 
737  const mapped_type&
738  at(const key_type& __k) const
739  {
740  auto __ite = static_cast<const __hashtable*>(this)->find(__k);
741  if (!__ite._M_cur)
742  __throw_out_of_range(__N("unordered_map::at"));
743  return __ite->second;
744  }
745  };
746 
747  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
748  typename _Hash, typename _RangeHash, typename _Unused,
749  typename _RehashPolicy, typename _Traits>
750  auto
751  _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
752  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
753  operator[](const key_type& __k)
754  -> mapped_type&
755  {
756  __hashtable* __h = static_cast<__hashtable*>(this);
757  __hash_code __code = __h->_M_hash_code(__k);
758  std::size_t __bkt = __h->_M_bucket_index(__code);
759  if (auto __node = __h->_M_find_node(__bkt, __k, __code))
760  return __node->_M_v().second;
761 
762  typename __hashtable::_Scoped_node __node {
763  __h,
766  std::tuple<>()
767  };
768  auto __pos
769  = __h->_M_insert_unique_node(__bkt, __code, __node._M_node);
770  __node._M_node = nullptr;
771  return __pos->second;
772  }
773 
774  template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
775  typename _Hash, typename _RangeHash, typename _Unused,
776  typename _RehashPolicy, typename _Traits>
777  auto
778  _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
779  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
780  operator[](key_type&& __k)
781  -> mapped_type&
782  {
783  __hashtable* __h = static_cast<__hashtable*>(this);
784  __hash_code __code = __h->_M_hash_code(__k);
785  std::size_t __bkt = __h->_M_bucket_index(__code);
786  if (auto __node = __h->_M_find_node(__bkt, __k, __code))
787  return __node->_M_v().second;
788 
789  typename __hashtable::_Scoped_node __node {
790  __h,
793  std::tuple<>()
794  };
795  auto __pos
796  = __h->_M_insert_unique_node(__bkt, __code, __node._M_node);
797  __node._M_node = nullptr;
798  return __pos->second;
799  }
800 
801  /**
802  * Primary class template _Insert_base.
803  *
804  * Defines @c insert member functions appropriate to all _Hashtables.
805  */
806  template<typename _Key, typename _Value, typename _Alloc,
807  typename _ExtractKey, typename _Equal,
808  typename _Hash, typename _RangeHash, typename _Unused,
809  typename _RehashPolicy, typename _Traits>
810  struct _Insert_base
811  {
812  protected:
813  using __hashtable_base = _Hashtable_base<_Key, _Value, _ExtractKey,
814  _Equal, _Hash, _RangeHash,
815  _Unused, _Traits>;
816 
817  using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
818  _Hash, _RangeHash,
819  _Unused, _RehashPolicy, _Traits>;
820 
821  using __hash_cached = typename _Traits::__hash_cached;
822  using __constant_iterators = typename _Traits::__constant_iterators;
823 
824  using __hashtable_alloc = _Hashtable_alloc<
825  __alloc_rebind<_Alloc, _Hash_node<_Value,
826  __hash_cached::value>>>;
827 
828  using value_type = typename __hashtable_base::value_type;
829  using size_type = typename __hashtable_base::size_type;
830 
831  using __unique_keys = typename _Traits::__unique_keys;
832  using __node_alloc_type = typename __hashtable_alloc::__node_alloc_type;
833  using __node_gen_type = _AllocNode<__node_alloc_type>;
834 
835  __hashtable&
836  _M_conjure_hashtable()
837  { return *(static_cast<__hashtable*>(this)); }
838 
839  template<typename _InputIterator, typename _NodeGetter>
840  void
841  _M_insert_range(_InputIterator __first, _InputIterator __last,
842  const _NodeGetter&, true_type __uks);
843 
844  template<typename _InputIterator, typename _NodeGetter>
845  void
846  _M_insert_range(_InputIterator __first, _InputIterator __last,
847  const _NodeGetter&, false_type __uks);
848 
849  public:
850  using iterator = _Node_iterator<_Value, __constant_iterators::value,
851  __hash_cached::value>;
852 
853  using const_iterator = _Node_const_iterator<_Value,
854  __constant_iterators::value,
855  __hash_cached::value>;
856 
857  using __ireturn_type = __conditional_t<__unique_keys::value,
859  iterator>;
860 
861  __ireturn_type
862  insert(const value_type& __v)
863  {
864  __hashtable& __h = _M_conjure_hashtable();
865  __node_gen_type __node_gen(__h);
866  return __h._M_insert(__v, __node_gen, __unique_keys{});
867  }
868 
869  iterator
870  insert(const_iterator __hint, const value_type& __v)
871  {
872  __hashtable& __h = _M_conjure_hashtable();
873  __node_gen_type __node_gen(__h);
874  return __h._M_insert(__hint, __v, __node_gen, __unique_keys{});
875  }
876 
877  template<typename _KType, typename... _Args>
879  try_emplace(const_iterator, _KType&& __k, _Args&&... __args)
880  {
881  __hashtable& __h = _M_conjure_hashtable();
882  auto __code = __h._M_hash_code(__k);
883  std::size_t __bkt = __h._M_bucket_index(__code);
884  if (auto __node = __h._M_find_node(__bkt, __k, __code))
885  return { iterator(__node), false };
886 
887  typename __hashtable::_Scoped_node __node {
888  &__h,
890  std::forward_as_tuple(std::forward<_KType>(__k)),
891  std::forward_as_tuple(std::forward<_Args>(__args)...)
892  };
893  auto __it
894  = __h._M_insert_unique_node(__bkt, __code, __node._M_node);
895  __node._M_node = nullptr;
896  return { __it, true };
897  }
898 
899  void
900  insert(initializer_list<value_type> __l)
901  { this->insert(__l.begin(), __l.end()); }
902 
903  template<typename _InputIterator>
904  void
905  insert(_InputIterator __first, _InputIterator __last)
906  {
907  __hashtable& __h = _M_conjure_hashtable();
908  __node_gen_type __node_gen(__h);
909  return _M_insert_range(__first, __last, __node_gen, __unique_keys{});
910  }
911  };
912 
913  template<typename _Key, typename _Value, typename _Alloc,
914  typename _ExtractKey, typename _Equal,
915  typename _Hash, typename _RangeHash, typename _Unused,
916  typename _RehashPolicy, typename _Traits>
917  template<typename _InputIterator, typename _NodeGetter>
918  void
919  _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
920  _Hash, _RangeHash, _Unused,
921  _RehashPolicy, _Traits>::
922  _M_insert_range(_InputIterator __first, _InputIterator __last,
923  const _NodeGetter& __node_gen, true_type __uks)
924  {
925  __hashtable& __h = _M_conjure_hashtable();
926  for (; __first != __last; ++__first)
927  __h._M_insert(*__first, __node_gen, __uks);
928  }
929 
930  template<typename _Key, typename _Value, typename _Alloc,
931  typename _ExtractKey, typename _Equal,
932  typename _Hash, typename _RangeHash, typename _Unused,
933  typename _RehashPolicy, typename _Traits>
934  template<typename _InputIterator, typename _NodeGetter>
935  void
936  _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
937  _Hash, _RangeHash, _Unused,
938  _RehashPolicy, _Traits>::
939  _M_insert_range(_InputIterator __first, _InputIterator __last,
940  const _NodeGetter& __node_gen, false_type __uks)
941  {
942  using __rehash_type = typename __hashtable::__rehash_type;
943  using __rehash_state = typename __hashtable::__rehash_state;
944  using pair_type = std::pair<bool, std::size_t>;
945 
946  size_type __n_elt = __detail::__distance_fw(__first, __last);
947  if (__n_elt == 0)
948  return;
949 
950  __hashtable& __h = _M_conjure_hashtable();
951  __rehash_type& __rehash = __h._M_rehash_policy;
952  const __rehash_state& __saved_state = __rehash._M_state();
953  pair_type __do_rehash = __rehash._M_need_rehash(__h._M_bucket_count,
954  __h._M_element_count,
955  __n_elt);
956 
957  if (__do_rehash.first)
958  __h._M_rehash(__do_rehash.second, __saved_state);
959 
960  for (; __first != __last; ++__first)
961  __h._M_insert(*__first, __node_gen, __uks);
962  }
963 
964  /**
965  * Primary class template _Insert.
966  *
967  * Defines @c insert member functions that depend on _Hashtable policies,
968  * via partial specializations.
969  */
970  template<typename _Key, typename _Value, typename _Alloc,
971  typename _ExtractKey, typename _Equal,
972  typename _Hash, typename _RangeHash, typename _Unused,
973  typename _RehashPolicy, typename _Traits,
974  bool _Constant_iterators = _Traits::__constant_iterators::value>
975  struct _Insert;
976 
977  /// Specialization.
978  template<typename _Key, typename _Value, typename _Alloc,
979  typename _ExtractKey, typename _Equal,
980  typename _Hash, typename _RangeHash, typename _Unused,
981  typename _RehashPolicy, typename _Traits>
982  struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
983  _Hash, _RangeHash, _Unused,
984  _RehashPolicy, _Traits, true>
985  : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
986  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>
987  {
988  using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
989  _Equal, _Hash, _RangeHash, _Unused,
990  _RehashPolicy, _Traits>;
991 
992  using value_type = typename __base_type::value_type;
993  using iterator = typename __base_type::iterator;
994  using const_iterator = typename __base_type::const_iterator;
995  using __ireturn_type = typename __base_type::__ireturn_type;
996 
997  using __unique_keys = typename __base_type::__unique_keys;
998  using __hashtable = typename __base_type::__hashtable;
999  using __node_gen_type = typename __base_type::__node_gen_type;
1000 
1001  using __base_type::insert;
1002 
1003  __ireturn_type
1004  insert(value_type&& __v)
1005  {
1006  __hashtable& __h = this->_M_conjure_hashtable();
1007  __node_gen_type __node_gen(__h);
1008  return __h._M_insert(std::move(__v), __node_gen, __unique_keys{});
1009  }
1010 
1011  iterator
1012  insert(const_iterator __hint, value_type&& __v)
1013  {
1014  __hashtable& __h = this->_M_conjure_hashtable();
1015  __node_gen_type __node_gen(__h);
1016  return __h._M_insert(__hint, std::move(__v), __node_gen,
1017  __unique_keys{});
1018  }
1019  };
1020 
1021  /// Specialization.
1022  template<typename _Key, typename _Value, typename _Alloc,
1023  typename _ExtractKey, typename _Equal,
1024  typename _Hash, typename _RangeHash, typename _Unused,
1025  typename _RehashPolicy, typename _Traits>
1026  struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1027  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
1028  : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1029  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>
1030  {
1031  using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
1032  _Equal, _Hash, _RangeHash, _Unused,
1033  _RehashPolicy, _Traits>;
1034  using value_type = typename __base_type::value_type;
1035  using iterator = typename __base_type::iterator;
1036  using const_iterator = typename __base_type::const_iterator;
1037 
1038  using __unique_keys = typename __base_type::__unique_keys;
1039  using __hashtable = typename __base_type::__hashtable;
1040  using __ireturn_type = typename __base_type::__ireturn_type;
1041 
1042  using __base_type::insert;
1043 
1044  template<typename _Pair>
1046 
1047  template<typename _Pair>
1048  using _IFcons = std::enable_if<__is_cons<_Pair>::value>;
1049 
1050  template<typename _Pair>
1051  using _IFconsp = typename _IFcons<_Pair>::type;
1052 
1053  template<typename _Pair, typename = _IFconsp<_Pair>>
1054  __ireturn_type
1055  insert(_Pair&& __v)
1056  {
1057  __hashtable& __h = this->_M_conjure_hashtable();
1058  return __h._M_emplace(__unique_keys{}, std::forward<_Pair>(__v));
1059  }
1060 
1061  template<typename _Pair, typename = _IFconsp<_Pair>>
1062  iterator
1063  insert(const_iterator __hint, _Pair&& __v)
1064  {
1065  __hashtable& __h = this->_M_conjure_hashtable();
1066  return __h._M_emplace(__hint, __unique_keys{},
1067  std::forward<_Pair>(__v));
1068  }
1069  };
1070 
1071  template<typename _Policy>
1072  using __has_load_factor = typename _Policy::__has_load_factor;
1073 
1074  /**
1075  * Primary class template _Rehash_base.
1076  *
1077  * Give hashtable the max_load_factor functions and reserve iff the
1078  * rehash policy supports it.
1079  */
1080  template<typename _Key, typename _Value, typename _Alloc,
1081  typename _ExtractKey, typename _Equal,
1082  typename _Hash, typename _RangeHash, typename _Unused,
1083  typename _RehashPolicy, typename _Traits,
1084  typename =
1085  __detected_or_t<false_type, __has_load_factor, _RehashPolicy>>
1086  struct _Rehash_base;
1087 
1088  /// Specialization when rehash policy doesn't provide load factor management.
1089  template<typename _Key, typename _Value, typename _Alloc,
1090  typename _ExtractKey, typename _Equal,
1091  typename _Hash, typename _RangeHash, typename _Unused,
1092  typename _RehashPolicy, typename _Traits>
1093  struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1094  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits,
1095  false_type /* Has load factor */>
1096  {
1097  };
1098 
1099  /// Specialization when rehash policy provide load factor management.
1100  template<typename _Key, typename _Value, typename _Alloc,
1101  typename _ExtractKey, typename _Equal,
1102  typename _Hash, typename _RangeHash, typename _Unused,
1103  typename _RehashPolicy, typename _Traits>
1104  struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1105  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits,
1106  true_type /* Has load factor */>
1107  {
1108  using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
1109  _Equal, _Hash, _RangeHash, _Unused,
1110  _RehashPolicy, _Traits>;
1111 
1112  float
1113  max_load_factor() const noexcept
1114  {
1115  const __hashtable* __this = static_cast<const __hashtable*>(this);
1116  return __this->__rehash_policy().max_load_factor();
1117  }
1118 
1119  void
1120  max_load_factor(float __z)
1121  {
1122  __hashtable* __this = static_cast<__hashtable*>(this);
1123  __this->__rehash_policy(_RehashPolicy(__z));
1124  }
1125 
1126  void
1127  reserve(std::size_t __n)
1128  {
1129  __hashtable* __this = static_cast<__hashtable*>(this);
1130  __this->rehash(__this->__rehash_policy()._M_bkt_for_elements(__n));
1131  }
1132  };
1133 
1134  /**
1135  * Primary class template _Hashtable_ebo_helper.
1136  *
1137  * Helper class using EBO when it is not forbidden (the type is not
1138  * final) and when it is worth it (the type is empty.)
1139  */
1140  template<int _Nm, typename _Tp,
1141  bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
1142  struct _Hashtable_ebo_helper;
1143 
1144  /// Specialization using EBO.
1145  template<int _Nm, typename _Tp>
1146  struct _Hashtable_ebo_helper<_Nm, _Tp, true>
1147  : private _Tp
1148  {
1149  _Hashtable_ebo_helper() noexcept(noexcept(_Tp())) : _Tp() { }
1150 
1151  template<typename _OtherTp>
1152  _Hashtable_ebo_helper(_OtherTp&& __tp)
1153  : _Tp(std::forward<_OtherTp>(__tp))
1154  { }
1155 
1156  const _Tp& _M_cget() const { return static_cast<const _Tp&>(*this); }
1157  _Tp& _M_get() { return static_cast<_Tp&>(*this); }
1158  };
1159 
1160  /// Specialization not using EBO.
1161  template<int _Nm, typename _Tp>
1162  struct _Hashtable_ebo_helper<_Nm, _Tp, false>
1163  {
1164  _Hashtable_ebo_helper() = default;
1165 
1166  template<typename _OtherTp>
1167  _Hashtable_ebo_helper(_OtherTp&& __tp)
1168  : _M_tp(std::forward<_OtherTp>(__tp))
1169  { }
1170 
1171  const _Tp& _M_cget() const { return _M_tp; }
1172  _Tp& _M_get() { return _M_tp; }
1173 
1174  private:
1175  _Tp _M_tp{};
1176  };
1177 
1178  /**
1179  * Primary class template _Local_iterator_base.
1180  *
1181  * Base class for local iterators, used to iterate within a bucket
1182  * but not between buckets.
1183  */
1184  template<typename _Key, typename _Value, typename _ExtractKey,
1185  typename _Hash, typename _RangeHash, typename _Unused,
1186  bool __cache_hash_code>
1187  struct _Local_iterator_base;
1188 
1189  /**
1190  * Primary class template _Hash_code_base.
1191  *
1192  * Encapsulates two policy issues that aren't quite orthogonal.
1193  * (1) the difference between using a ranged hash function and using
1194  * the combination of a hash function and a range-hashing function.
1195  * In the former case we don't have such things as hash codes, so
1196  * we have a dummy type as placeholder.
1197  * (2) Whether or not we cache hash codes. Caching hash codes is
1198  * meaningless if we have a ranged hash function.
1199  *
1200  * We also put the key extraction objects here, for convenience.
1201  * Each specialization derives from one or more of the template
1202  * parameters to benefit from Ebo. This is important as this type
1203  * is inherited in some cases by the _Local_iterator_base type used
1204  * to implement local_iterator and const_local_iterator. As with
1205  * any iterator type we prefer to make it as small as possible.
1206  */
1207  template<typename _Key, typename _Value, typename _ExtractKey,
1208  typename _Hash, typename _RangeHash, typename _Unused,
1209  bool __cache_hash_code>
1210  struct _Hash_code_base
1211  : private _Hashtable_ebo_helper<1, _Hash>
1212  {
1213  private:
1214  using __ebo_hash = _Hashtable_ebo_helper<1, _Hash>;
1215 
1216  // Gives the local iterator implementation access to _M_bucket_index().
1217  friend struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1218  _Hash, _RangeHash, _Unused, false>;
1219 
1220  public:
1221  typedef _Hash hasher;
1222 
1223  hasher
1224  hash_function() const
1225  { return _M_hash(); }
1226 
1227  protected:
1228  typedef std::size_t __hash_code;
1229 
1230  // We need the default constructor for the local iterators and _Hashtable
1231  // default constructor.
1232  _Hash_code_base() = default;
1233 
1234  _Hash_code_base(const _Hash& __hash) : __ebo_hash(__hash) { }
1235 
1236  __hash_code
1237  _M_hash_code(const _Key& __k) const
1238  {
1239  static_assert(__is_invocable<const _Hash&, const _Key&>{},
1240  "hash function must be invocable with an argument of key type");
1241  return _M_hash()(__k);
1242  }
1243 
1244  template<typename _Kt>
1245  __hash_code
1246  _M_hash_code_tr(const _Kt& __k) const
1247  {
1248  static_assert(__is_invocable<const _Hash&, const _Kt&>{},
1249  "hash function must be invocable with an argument of key type");
1250  return _M_hash()(__k);
1251  }
1252 
1253  __hash_code
1254  _M_hash_code(const _Hash&,
1255  const _Hash_node_value<_Value, true>& __n) const
1256  { return __n._M_hash_code; }
1257 
1258  // Compute hash code using _Hash as __n _M_hash_code, if present, was
1259  // computed using _H2.
1260  template<typename _H2>
1261  __hash_code
1262  _M_hash_code(const _H2&,
1263  const _Hash_node_value<_Value, __cache_hash_code>& __n) const
1264  { return _M_hash_code(_ExtractKey{}(__n._M_v())); }
1265 
1266  std::size_t
1267  _M_bucket_index(__hash_code __c, std::size_t __bkt_count) const
1268  { return _RangeHash{}(__c, __bkt_count); }
1269 
1270  std::size_t
1271  _M_bucket_index(const _Hash_node_value<_Value, false>& __n,
1272  std::size_t __bkt_count) const
1273  noexcept( noexcept(declval<const _Hash&>()(declval<const _Key&>()))
1274  && noexcept(declval<const _RangeHash&>()((__hash_code)0,
1275  (std::size_t)0)) )
1276  {
1277  return _RangeHash{}(_M_hash_code(_ExtractKey{}(__n._M_v())),
1278  __bkt_count);
1279  }
1280 
1281  std::size_t
1282  _M_bucket_index(const _Hash_node_value<_Value, true>& __n,
1283  std::size_t __bkt_count) const
1284  noexcept( noexcept(declval<const _RangeHash&>()((__hash_code)0,
1285  (std::size_t)0)) )
1286  { return _RangeHash{}(__n._M_hash_code, __bkt_count); }
1287 
1288  void
1289  _M_store_code(_Hash_node_code_cache<false>&, __hash_code) const
1290  { }
1291 
1292  void
1293  _M_copy_code(_Hash_node_code_cache<false>&,
1294  const _Hash_node_code_cache<false>&) const
1295  { }
1296 
1297  void
1298  _M_store_code(_Hash_node_code_cache<true>& __n, __hash_code __c) const
1299  { __n._M_hash_code = __c; }
1300 
1301  void
1302  _M_copy_code(_Hash_node_code_cache<true>& __to,
1303  const _Hash_node_code_cache<true>& __from) const
1304  { __to._M_hash_code = __from._M_hash_code; }
1305 
1306  void
1307  _M_swap(_Hash_code_base& __x)
1308  { std::swap(__ebo_hash::_M_get(), __x.__ebo_hash::_M_get()); }
1309 
1310  const _Hash&
1311  _M_hash() const { return __ebo_hash::_M_cget(); }
1312  };
1313 
1314  /// Partial specialization used when nodes contain a cached hash code.
1315  template<typename _Key, typename _Value, typename _ExtractKey,
1316  typename _Hash, typename _RangeHash, typename _Unused>
1317  struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1318  _Hash, _RangeHash, _Unused, true>
1319  : public _Node_iterator_base<_Value, true>
1320  {
1321  protected:
1322  using __base_node_iter = _Node_iterator_base<_Value, true>;
1323  using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1324  _Hash, _RangeHash, _Unused, true>;
1325 
1326  _Local_iterator_base() = default;
1327  _Local_iterator_base(const __hash_code_base&,
1328  _Hash_node<_Value, true>* __p,
1329  std::size_t __bkt, std::size_t __bkt_count)
1330  : __base_node_iter(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
1331  { }
1332 
1333  void
1334  _M_incr()
1335  {
1336  __base_node_iter::_M_incr();
1337  if (this->_M_cur)
1338  {
1339  std::size_t __bkt
1340  = _RangeHash{}(this->_M_cur->_M_hash_code, _M_bucket_count);
1341  if (__bkt != _M_bucket)
1342  this->_M_cur = nullptr;
1343  }
1344  }
1345 
1346  std::size_t _M_bucket;
1347  std::size_t _M_bucket_count;
1348 
1349  public:
1350  std::size_t
1351  _M_get_bucket() const { return _M_bucket; } // for debug mode
1352  };
1353 
1354  // Uninitialized storage for a _Hash_code_base.
1355  // This type is DefaultConstructible and Assignable even if the
1356  // _Hash_code_base type isn't, so that _Local_iterator_base<..., false>
1357  // can be DefaultConstructible and Assignable.
1358  template<typename _Tp, bool _IsEmpty = std::is_empty<_Tp>::value>
1359  struct _Hash_code_storage
1360  {
1361  __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
1362 
1363  _Tp*
1364  _M_h() { return _M_storage._M_ptr(); }
1365 
1366  const _Tp*
1367  _M_h() const { return _M_storage._M_ptr(); }
1368  };
1369 
1370  // Empty partial specialization for empty _Hash_code_base types.
1371  template<typename _Tp>
1372  struct _Hash_code_storage<_Tp, true>
1373  {
1374  static_assert( std::is_empty<_Tp>::value, "Type must be empty" );
1375 
1376  // As _Tp is an empty type there will be no bytes written/read through
1377  // the cast pointer, so no strict-aliasing violation.
1378  _Tp*
1379  _M_h() { return reinterpret_cast<_Tp*>(this); }
1380 
1381  const _Tp*
1382  _M_h() const { return reinterpret_cast<const _Tp*>(this); }
1383  };
1384 
1385  template<typename _Key, typename _Value, typename _ExtractKey,
1386  typename _Hash, typename _RangeHash, typename _Unused>
1387  using __hash_code_for_local_iter
1388  = _Hash_code_storage<_Hash_code_base<_Key, _Value, _ExtractKey,
1389  _Hash, _RangeHash, _Unused, false>>;
1390 
1391  // Partial specialization used when hash codes are not cached
1392  template<typename _Key, typename _Value, typename _ExtractKey,
1393  typename _Hash, typename _RangeHash, typename _Unused>
1394  struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1395  _Hash, _RangeHash, _Unused, false>
1396  : __hash_code_for_local_iter<_Key, _Value, _ExtractKey, _Hash, _RangeHash,
1397  _Unused>
1398  , _Node_iterator_base<_Value, false>
1399  {
1400  protected:
1401  using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1402  _Hash, _RangeHash, _Unused, false>;
1403  using __node_iter_base = _Node_iterator_base<_Value, false>;
1404 
1405  _Local_iterator_base() : _M_bucket_count(-1) { }
1406 
1407  _Local_iterator_base(const __hash_code_base& __base,
1408  _Hash_node<_Value, false>* __p,
1409  std::size_t __bkt, std::size_t __bkt_count)
1410  : __node_iter_base(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
1411  { _M_init(__base); }
1412 
1413  ~_Local_iterator_base()
1414  {
1415  if (_M_bucket_count != size_t(-1))
1416  _M_destroy();
1417  }
1418 
1419  _Local_iterator_base(const _Local_iterator_base& __iter)
1420  : __node_iter_base(__iter._M_cur), _M_bucket(__iter._M_bucket)
1421  , _M_bucket_count(__iter._M_bucket_count)
1422  {
1423  if (_M_bucket_count != size_t(-1))
1424  _M_init(*__iter._M_h());
1425  }
1426 
1427  _Local_iterator_base&
1428  operator=(const _Local_iterator_base& __iter)
1429  {
1430  if (_M_bucket_count != -1)
1431  _M_destroy();
1432  this->_M_cur = __iter._M_cur;
1433  _M_bucket = __iter._M_bucket;
1434  _M_bucket_count = __iter._M_bucket_count;
1435  if (_M_bucket_count != -1)
1436  _M_init(*__iter._M_h());
1437  return *this;
1438  }
1439 
1440  void
1441  _M_incr()
1442  {
1443  __node_iter_base::_M_incr();
1444  if (this->_M_cur)
1445  {
1446  std::size_t __bkt = this->_M_h()->_M_bucket_index(*this->_M_cur,
1447  _M_bucket_count);
1448  if (__bkt != _M_bucket)
1449  this->_M_cur = nullptr;
1450  }
1451  }
1452 
1453  std::size_t _M_bucket;
1454  std::size_t _M_bucket_count;
1455 
1456  void
1457  _M_init(const __hash_code_base& __base)
1458  { ::new(this->_M_h()) __hash_code_base(__base); }
1459 
1460  void
1461  _M_destroy() { this->_M_h()->~__hash_code_base(); }
1462 
1463  public:
1464  std::size_t
1465  _M_get_bucket() const { return _M_bucket; } // for debug mode
1466  };
1467 
1468  /// local iterators
1469  template<typename _Key, typename _Value, typename _ExtractKey,
1470  typename _Hash, typename _RangeHash, typename _Unused,
1471  bool __constant_iterators, bool __cache>
1472  struct _Local_iterator
1473  : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1474  _Hash, _RangeHash, _Unused, __cache>
1475  {
1476  private:
1477  using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1478  _Hash, _RangeHash, _Unused, __cache>;
1479  using __hash_code_base = typename __base_type::__hash_code_base;
1480 
1481  public:
1482  using value_type = _Value;
1483  using pointer = __conditional_t<__constant_iterators,
1484  const value_type*, value_type*>;
1485  using reference = __conditional_t<__constant_iterators,
1486  const value_type&, value_type&>;
1487  using difference_type = ptrdiff_t;
1488  using iterator_category = forward_iterator_tag;
1489 
1490  _Local_iterator() = default;
1491 
1492  _Local_iterator(const __hash_code_base& __base,
1493  _Hash_node<_Value, __cache>* __n,
1494  std::size_t __bkt, std::size_t __bkt_count)
1495  : __base_type(__base, __n, __bkt, __bkt_count)
1496  { }
1497 
1498  reference
1499  operator*() const
1500  { return this->_M_cur->_M_v(); }
1501 
1502  pointer
1503  operator->() const
1504  { return this->_M_cur->_M_valptr(); }
1505 
1506  _Local_iterator&
1507  operator++()
1508  {
1509  this->_M_incr();
1510  return *this;
1511  }
1512 
1513  _Local_iterator
1514  operator++(int)
1515  {
1516  _Local_iterator __tmp(*this);
1517  this->_M_incr();
1518  return __tmp;
1519  }
1520  };
1521 
1522  /// local const_iterators
1523  template<typename _Key, typename _Value, typename _ExtractKey,
1524  typename _Hash, typename _RangeHash, typename _Unused,
1525  bool __constant_iterators, bool __cache>
1526  struct _Local_const_iterator
1527  : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1528  _Hash, _RangeHash, _Unused, __cache>
1529  {
1530  private:
1531  using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1532  _Hash, _RangeHash, _Unused, __cache>;
1533  using __hash_code_base = typename __base_type::__hash_code_base;
1534 
1535  public:
1536  typedef _Value value_type;
1537  typedef const value_type* pointer;
1538  typedef const value_type& reference;
1539  typedef std::ptrdiff_t difference_type;
1540  typedef std::forward_iterator_tag iterator_category;
1541 
1542  _Local_const_iterator() = default;
1543 
1544  _Local_const_iterator(const __hash_code_base& __base,
1545  _Hash_node<_Value, __cache>* __n,
1546  std::size_t __bkt, std::size_t __bkt_count)
1547  : __base_type(__base, __n, __bkt, __bkt_count)
1548  { }
1549 
1550  _Local_const_iterator(const _Local_iterator<_Key, _Value, _ExtractKey,
1551  _Hash, _RangeHash, _Unused,
1552  __constant_iterators,
1553  __cache>& __x)
1554  : __base_type(__x)
1555  { }
1556 
1557  reference
1558  operator*() const
1559  { return this->_M_cur->_M_v(); }
1560 
1561  pointer
1562  operator->() const
1563  { return this->_M_cur->_M_valptr(); }
1564 
1565  _Local_const_iterator&
1566  operator++()
1567  {
1568  this->_M_incr();
1569  return *this;
1570  }
1571 
1572  _Local_const_iterator
1573  operator++(int)
1574  {
1575  _Local_const_iterator __tmp(*this);
1576  this->_M_incr();
1577  return __tmp;
1578  }
1579  };
1580 
1581  /**
1582  * Primary class template _Hashtable_base.
1583  *
1584  * Helper class adding management of _Equal functor to
1585  * _Hash_code_base type.
1586  *
1587  * Base class templates are:
1588  * - __detail::_Hash_code_base
1589  * - __detail::_Hashtable_ebo_helper
1590  */
1591  template<typename _Key, typename _Value, typename _ExtractKey,
1592  typename _Equal, typename _Hash, typename _RangeHash,
1593  typename _Unused, typename _Traits>
1594  struct _Hashtable_base
1595  : public _Hash_code_base<_Key, _Value, _ExtractKey, _Hash, _RangeHash,
1596  _Unused, _Traits::__hash_cached::value>,
1597  private _Hashtable_ebo_helper<0, _Equal>
1598  {
1599  public:
1600  typedef _Key key_type;
1601  typedef _Value value_type;
1602  typedef _Equal key_equal;
1603  typedef std::size_t size_type;
1604  typedef std::ptrdiff_t difference_type;
1605 
1606  using __traits_type = _Traits;
1607  using __hash_cached = typename __traits_type::__hash_cached;
1608 
1609  using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1610  _Hash, _RangeHash, _Unused,
1611  __hash_cached::value>;
1612 
1613  using __hash_code = typename __hash_code_base::__hash_code;
1614 
1615  private:
1616  using _EqualEBO = _Hashtable_ebo_helper<0, _Equal>;
1617 
1618  static bool
1619  _S_equals(__hash_code, const _Hash_node_code_cache<false>&)
1620  { return true; }
1621 
1622  static bool
1623  _S_node_equals(const _Hash_node_code_cache<false>&,
1624  const _Hash_node_code_cache<false>&)
1625  { return true; }
1626 
1627  static bool
1628  _S_equals(__hash_code __c, const _Hash_node_code_cache<true>& __n)
1629  { return __c == __n._M_hash_code; }
1630 
1631  static bool
1632  _S_node_equals(const _Hash_node_code_cache<true>& __lhn,
1633  const _Hash_node_code_cache<true>& __rhn)
1634  { return __lhn._M_hash_code == __rhn._M_hash_code; }
1635 
1636  protected:
1637  _Hashtable_base() = default;
1638 
1639  _Hashtable_base(const _Hash& __hash, const _Equal& __eq)
1640  : __hash_code_base(__hash), _EqualEBO(__eq)
1641  { }
1642 
1643  bool
1644  _M_equals(const _Key& __k, __hash_code __c,
1645  const _Hash_node_value<_Value, __hash_cached::value>& __n) const
1646  {
1647  static_assert(__is_invocable<const _Equal&, const _Key&, const _Key&>{},
1648  "key equality predicate must be invocable with two arguments of "
1649  "key type");
1650  return _S_equals(__c, __n) && _M_eq()(__k, _ExtractKey{}(__n._M_v()));
1651  }
1652 
1653  template<typename _Kt>
1654  bool
1655  _M_equals_tr(const _Kt& __k, __hash_code __c,
1656  const _Hash_node_value<_Value,
1657  __hash_cached::value>& __n) const
1658  {
1659  static_assert(
1660  __is_invocable<const _Equal&, const _Kt&, const _Key&>{},
1661  "key equality predicate must be invocable with two arguments of "
1662  "key type");
1663  return _S_equals(__c, __n) && _M_eq()(__k, _ExtractKey{}(__n._M_v()));
1664  }
1665 
1666  bool
1667  _M_node_equals(
1668  const _Hash_node_value<_Value, __hash_cached::value>& __lhn,
1669  const _Hash_node_value<_Value, __hash_cached::value>& __rhn) const
1670  {
1671  return _S_node_equals(__lhn, __rhn)
1672  && _M_eq()(_ExtractKey{}(__lhn._M_v()), _ExtractKey{}(__rhn._M_v()));
1673  }
1674 
1675  void
1676  _M_swap(_Hashtable_base& __x)
1677  {
1678  __hash_code_base::_M_swap(__x);
1679  std::swap(_EqualEBO::_M_get(), __x._EqualEBO::_M_get());
1680  }
1681 
1682  const _Equal&
1683  _M_eq() const { return _EqualEBO::_M_cget(); }
1684  };
1685 
1686  /**
1687  * Primary class template _Equality.
1688  *
1689  * This is for implementing equality comparison for unordered
1690  * containers, per N3068, by John Lakos and Pablo Halpern.
1691  * Algorithmically, we follow closely the reference implementations
1692  * therein.
1693  */
1694  template<typename _Key, typename _Value, typename _Alloc,
1695  typename _ExtractKey, typename _Equal,
1696  typename _Hash, typename _RangeHash, typename _Unused,
1697  typename _RehashPolicy, typename _Traits,
1698  bool _Unique_keys = _Traits::__unique_keys::value>
1699  struct _Equality;
1700 
1701  /// unordered_map and unordered_set specializations.
1702  template<typename _Key, typename _Value, typename _Alloc,
1703  typename _ExtractKey, typename _Equal,
1704  typename _Hash, typename _RangeHash, typename _Unused,
1705  typename _RehashPolicy, typename _Traits>
1706  struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1707  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>
1708  {
1709  using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1710  _Hash, _RangeHash, _Unused,
1711  _RehashPolicy, _Traits>;
1712 
1713  bool
1714  _M_equal(const __hashtable&) const;
1715  };
1716 
1717  template<typename _Key, typename _Value, typename _Alloc,
1718  typename _ExtractKey, typename _Equal,
1719  typename _Hash, typename _RangeHash, typename _Unused,
1720  typename _RehashPolicy, typename _Traits>
1721  bool
1722  _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1723  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
1724  _M_equal(const __hashtable& __other) const
1725  {
1726  using __node_type = typename __hashtable::__node_type;
1727  const __hashtable* __this = static_cast<const __hashtable*>(this);
1728  if (__this->size() != __other.size())
1729  return false;
1730 
1731  for (auto __itx = __this->begin(); __itx != __this->end(); ++__itx)
1732  {
1733  std::size_t __ybkt = __other._M_bucket_index(*__itx._M_cur);
1734  auto __prev_n = __other._M_buckets[__ybkt];
1735  if (!__prev_n)
1736  return false;
1737 
1738  for (__node_type* __n = static_cast<__node_type*>(__prev_n->_M_nxt);;
1739  __n = __n->_M_next())
1740  {
1741  if (__n->_M_v() == *__itx)
1742  break;
1743 
1744  if (!__n->_M_nxt
1745  || __other._M_bucket_index(*__n->_M_next()) != __ybkt)
1746  return false;
1747  }
1748  }
1749 
1750  return true;
1751  }
1752 
1753  /// unordered_multiset and unordered_multimap specializations.
1754  template<typename _Key, typename _Value, typename _Alloc,
1755  typename _ExtractKey, typename _Equal,
1756  typename _Hash, typename _RangeHash, typename _Unused,
1757  typename _RehashPolicy, typename _Traits>
1758  struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1759  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
1760  {
1761  using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1762  _Hash, _RangeHash, _Unused,
1763  _RehashPolicy, _Traits>;
1764 
1765  bool
1766  _M_equal(const __hashtable&) const;
1767  };
1768 
1769  template<typename _Key, typename _Value, typename _Alloc,
1770  typename _ExtractKey, typename _Equal,
1771  typename _Hash, typename _RangeHash, typename _Unused,
1772  typename _RehashPolicy, typename _Traits>
1773  bool
1774  _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1775  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>::
1776  _M_equal(const __hashtable& __other) const
1777  {
1778  using __node_type = typename __hashtable::__node_type;
1779  const __hashtable* __this = static_cast<const __hashtable*>(this);
1780  if (__this->size() != __other.size())
1781  return false;
1782 
1783  for (auto __itx = __this->begin(); __itx != __this->end();)
1784  {
1785  std::size_t __x_count = 1;
1786  auto __itx_end = __itx;
1787  for (++__itx_end; __itx_end != __this->end()
1788  && __this->key_eq()(_ExtractKey{}(*__itx),
1789  _ExtractKey{}(*__itx_end));
1790  ++__itx_end)
1791  ++__x_count;
1792 
1793  std::size_t __ybkt = __other._M_bucket_index(*__itx._M_cur);
1794  auto __y_prev_n = __other._M_buckets[__ybkt];
1795  if (!__y_prev_n)
1796  return false;
1797 
1798  __node_type* __y_n = static_cast<__node_type*>(__y_prev_n->_M_nxt);
1799  for (;;)
1800  {
1801  if (__this->key_eq()(_ExtractKey{}(__y_n->_M_v()),
1802  _ExtractKey{}(*__itx)))
1803  break;
1804 
1805  auto __y_ref_n = __y_n;
1806  for (__y_n = __y_n->_M_next(); __y_n; __y_n = __y_n->_M_next())
1807  if (!__other._M_node_equals(*__y_ref_n, *__y_n))
1808  break;
1809 
1810  if (!__y_n || __other._M_bucket_index(*__y_n) != __ybkt)
1811  return false;
1812  }
1813 
1814  typename __hashtable::const_iterator __ity(__y_n);
1815  for (auto __ity_end = __ity; __ity_end != __other.end(); ++__ity_end)
1816  if (--__x_count == 0)
1817  break;
1818 
1819  if (__x_count != 0)
1820  return false;
1821 
1822  if (!std::is_permutation(__itx, __itx_end, __ity))
1823  return false;
1824 
1825  __itx = __itx_end;
1826  }
1827  return true;
1828  }
1829 
1830  /**
1831  * This type deals with all allocation and keeps an allocator instance
1832  * through inheritance to benefit from EBO when possible.
1833  */
1834  template<typename _NodeAlloc>
1835  struct _Hashtable_alloc : private _Hashtable_ebo_helper<0, _NodeAlloc>
1836  {
1837  private:
1838  using __ebo_node_alloc = _Hashtable_ebo_helper<0, _NodeAlloc>;
1839 
1840  template<typename>
1841  struct __get_value_type;
1842  template<typename _Val, bool _Cache_hash_code>
1843  struct __get_value_type<_Hash_node<_Val, _Cache_hash_code>>
1844  { using type = _Val; };
1845 
1846  public:
1847  using __node_type = typename _NodeAlloc::value_type;
1848  using __node_alloc_type = _NodeAlloc;
1849  // Use __gnu_cxx to benefit from _S_always_equal and al.
1850  using __node_alloc_traits = __gnu_cxx::__alloc_traits<__node_alloc_type>;
1851 
1852  using __value_alloc_traits = typename __node_alloc_traits::template
1853  rebind_traits<typename __get_value_type<__node_type>::type>;
1854 
1855  using __node_ptr = __node_type*;
1856  using __node_base = _Hash_node_base;
1857  using __node_base_ptr = __node_base*;
1858  using __buckets_alloc_type =
1859  __alloc_rebind<__node_alloc_type, __node_base_ptr>;
1860  using __buckets_alloc_traits = std::allocator_traits<__buckets_alloc_type>;
1861  using __buckets_ptr = __node_base_ptr*;
1862 
1863  _Hashtable_alloc() = default;
1864  _Hashtable_alloc(const _Hashtable_alloc&) = default;
1865  _Hashtable_alloc(_Hashtable_alloc&&) = default;
1866 
1867  template<typename _Alloc>
1868  _Hashtable_alloc(_Alloc&& __a)
1869  : __ebo_node_alloc(std::forward<_Alloc>(__a))
1870  { }
1871 
1872  __node_alloc_type&
1873  _M_node_allocator()
1874  { return __ebo_node_alloc::_M_get(); }
1875 
1876  const __node_alloc_type&
1877  _M_node_allocator() const
1878  { return __ebo_node_alloc::_M_cget(); }
1879 
1880  // Allocate a node and construct an element within it.
1881  template<typename... _Args>
1882  __node_ptr
1883  _M_allocate_node(_Args&&... __args);
1884 
1885  // Destroy the element within a node and deallocate the node.
1886  void
1887  _M_deallocate_node(__node_ptr __n);
1888 
1889  // Deallocate a node.
1890  void
1891  _M_deallocate_node_ptr(__node_ptr __n);
1892 
1893  // Deallocate the linked list of nodes pointed to by __n.
1894  // The elements within the nodes are destroyed.
1895  void
1896  _M_deallocate_nodes(__node_ptr __n);
1897 
1898  __buckets_ptr
1899  _M_allocate_buckets(std::size_t __bkt_count);
1900 
1901  void
1902  _M_deallocate_buckets(__buckets_ptr, std::size_t __bkt_count);
1903  };
1904 
1905  // Definitions of class template _Hashtable_alloc's out-of-line member
1906  // functions.
1907  template<typename _NodeAlloc>
1908  template<typename... _Args>
1909  auto
1910  _Hashtable_alloc<_NodeAlloc>::_M_allocate_node(_Args&&... __args)
1911  -> __node_ptr
1912  {
1913  auto __nptr = __node_alloc_traits::allocate(_M_node_allocator(), 1);
1914  __node_ptr __n = std::__to_address(__nptr);
1915  __try
1916  {
1917  ::new ((void*)__n) __node_type;
1918  __node_alloc_traits::construct(_M_node_allocator(),
1919  __n->_M_valptr(),
1920  std::forward<_Args>(__args)...);
1921  return __n;
1922  }
1923  __catch(...)
1924  {
1925  __node_alloc_traits::deallocate(_M_node_allocator(), __nptr, 1);
1926  __throw_exception_again;
1927  }
1928  }
1929 
1930  template<typename _NodeAlloc>
1931  void
1932  _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node(__node_ptr __n)
1933  {
1934  __node_alloc_traits::destroy(_M_node_allocator(), __n->_M_valptr());
1935  _M_deallocate_node_ptr(__n);
1936  }
1937 
1938  template<typename _NodeAlloc>
1939  void
1940  _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node_ptr(__node_ptr __n)
1941  {
1942  typedef typename __node_alloc_traits::pointer _Ptr;
1943  auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__n);
1944  __n->~__node_type();
1945  __node_alloc_traits::deallocate(_M_node_allocator(), __ptr, 1);
1946  }
1947 
1948  template<typename _NodeAlloc>
1949  void
1950  _Hashtable_alloc<_NodeAlloc>::_M_deallocate_nodes(__node_ptr __n)
1951  {
1952  while (__n)
1953  {
1954  __node_ptr __tmp = __n;
1955  __n = __n->_M_next();
1956  _M_deallocate_node(__tmp);
1957  }
1958  }
1959 
1960  template<typename _NodeAlloc>
1961  auto
1962  _Hashtable_alloc<_NodeAlloc>::_M_allocate_buckets(std::size_t __bkt_count)
1963  -> __buckets_ptr
1964  {
1965  __buckets_alloc_type __alloc(_M_node_allocator());
1966 
1967  auto __ptr = __buckets_alloc_traits::allocate(__alloc, __bkt_count);
1968  __buckets_ptr __p = std::__to_address(__ptr);
1969  __builtin_memset(__p, 0, __bkt_count * sizeof(__node_base_ptr));
1970  return __p;
1971  }
1972 
1973  template<typename _NodeAlloc>
1974  void
1975  _Hashtable_alloc<_NodeAlloc>::
1976  _M_deallocate_buckets(__buckets_ptr __bkts,
1977  std::size_t __bkt_count)
1978  {
1979  typedef typename __buckets_alloc_traits::pointer _Ptr;
1980  auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__bkts);
1981  __buckets_alloc_type __alloc(_M_node_allocator());
1982  __buckets_alloc_traits::deallocate(__alloc, __ptr, __bkt_count);
1983  }
1984 
1985  ///@} hashtable-detail
1986 } // namespace __detail
1987 /// @endcond
1988 _GLIBCXX_END_NAMESPACE_VERSION
1989 } // namespace std
1990 
1991 #endif // _HASHTABLE_POLICY_H
constexpr complex< _Tp > operator*(const complex< _Tp > &__x, const complex< _Tp > &__y)
Return new complex value x times y.
Definition: complex:392
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:82
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:85
constexpr piecewise_construct_t piecewise_construct
Tag for piecewise construction of std::pair objects.
Definition: stl_pair.h:83
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:104
constexpr tuple< _Elements &&... > forward_as_tuple(_Elements &&... __args) noexcept
std::forward_as_tuple
Definition: tuple:1589
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
Definition: move.h:77
void swap(any &__x, any &__y) noexcept
Exchange the states of two any objects.
Definition: any:429
constexpr iterator_traits< _Iter >::iterator_category __iterator_category(const _Iter &)
ISO C++ entities toplevel namespace is std.
constexpr iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)
A generalization of pointer arithmetic.
__numeric_traits_integer< _Tp > __int_traits
Convenience alias for __numeric_traits<integer-type>.
constexpr _Iterator __base(_Iterator __it)
Primary class template, tuple.
Definition: tuple:610
is_empty
Definition: type_traits:782
is_constructible
Definition: type_traits:979
Define a member typedef type only if a boolean constant is true.
Definition: type_traits:2229
Uniform interface to all allocator types.
Traits class for iterators.
Uniform interface to all pointer-like types.
Definition: ptr_traits.h:192
Struct holding two objects of arbitrary type.
Definition: stl_pair.h:201
Marking input iterators.
Forward iterators support a superset of input iterator operations.
Uniform interface to C++98 and C++11 allocators.