libstdc++
hashtable_policy.h
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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<class _Iterator>
65  __distance_fw(_Iterator __first, _Iterator __last,
67  { return __first != __last ? 1 : 0; }
68 
69  template<class _Iterator>
71  __distance_fw(_Iterator __first, _Iterator __last,
73  { return std::distance(__first, __last); }
74 
75  template<class _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 _Tp>
92  auto
93  operator()(_Tp&& __x) const noexcept
94  -> decltype(std::get<0>(std::forward<_Tp>(__x)))
95  { return std::get<0>(std::forward<_Tp>(__x)); }
96  };
97 
98  template<typename _NodeAlloc>
99  struct _Hashtable_alloc;
100 
101  // Functor recycling a pool of nodes and using allocation once the pool is
102  // empty.
103  template<typename _NodeAlloc>
104  struct _ReuseOrAllocNode
105  {
106  private:
107  using __node_alloc_type = _NodeAlloc;
108  using __hashtable_alloc = _Hashtable_alloc<__node_alloc_type>;
109  using __node_alloc_traits =
110  typename __hashtable_alloc::__node_alloc_traits;
111  using __node_type = typename __hashtable_alloc::__node_type;
112 
113  public:
114  _ReuseOrAllocNode(__node_type* __nodes, __hashtable_alloc& __h)
115  : _M_nodes(__nodes), _M_h(__h) { }
116  _ReuseOrAllocNode(const _ReuseOrAllocNode&) = delete;
117 
118  ~_ReuseOrAllocNode()
119  { _M_h._M_deallocate_nodes(_M_nodes); }
120 
121  template<typename _Arg>
122  __node_type*
123  operator()(_Arg&& __arg) const
124  {
125  if (_M_nodes)
126  {
127  __node_type* __node = _M_nodes;
128  _M_nodes = _M_nodes->_M_next();
129  __node->_M_nxt = nullptr;
130  auto& __a = _M_h._M_node_allocator();
131  __node_alloc_traits::destroy(__a, __node->_M_valptr());
132  __try
133  {
134  __node_alloc_traits::construct(__a, __node->_M_valptr(),
135  std::forward<_Arg>(__arg));
136  }
137  __catch(...)
138  {
139  _M_h._M_deallocate_node_ptr(__node);
140  __throw_exception_again;
141  }
142  return __node;
143  }
144  return _M_h._M_allocate_node(std::forward<_Arg>(__arg));
145  }
146 
147  private:
148  mutable __node_type* _M_nodes;
149  __hashtable_alloc& _M_h;
150  };
151 
152  // Functor similar to the previous one but without any pool of nodes to
153  // recycle.
154  template<typename _NodeAlloc>
155  struct _AllocNode
156  {
157  private:
158  using __hashtable_alloc = _Hashtable_alloc<_NodeAlloc>;
159  using __node_type = typename __hashtable_alloc::__node_type;
160 
161  public:
162  _AllocNode(__hashtable_alloc& __h)
163  : _M_h(__h) { }
164 
165  template<typename _Arg>
166  __node_type*
167  operator()(_Arg&& __arg) const
168  { return _M_h._M_allocate_node(std::forward<_Arg>(__arg)); }
169 
170  private:
171  __hashtable_alloc& _M_h;
172  };
173 
174  // Auxiliary types used for all instantiations of _Hashtable nodes
175  // and iterators.
176 
177  /**
178  * struct _Hashtable_traits
179  *
180  * Important traits for hash tables.
181  *
182  * @tparam _Cache_hash_code Boolean value. True if the value of
183  * the hash function is stored along with the value. This is a
184  * time-space tradeoff. Storing it may improve lookup speed by
185  * reducing the number of times we need to call the _Hash or _Equal
186  * functors.
187  *
188  * @tparam _Constant_iterators Boolean value. True if iterator and
189  * const_iterator are both constant iterator types. This is true
190  * for unordered_set and unordered_multiset, false for
191  * unordered_map and unordered_multimap.
192  *
193  * @tparam _Unique_keys Boolean value. True if the return value
194  * of _Hashtable::count(k) is always at most one, false if it may
195  * be an arbitrary number. This is true for unordered_set and
196  * unordered_map, false for unordered_multiset and
197  * unordered_multimap.
198  */
199  template<bool _Cache_hash_code, bool _Constant_iterators, bool _Unique_keys>
200  struct _Hashtable_traits
201  {
202  using __hash_cached = __bool_constant<_Cache_hash_code>;
203  using __constant_iterators = __bool_constant<_Constant_iterators>;
204  using __unique_keys = __bool_constant<_Unique_keys>;
205  };
206 
207  /**
208  * struct _Hash_node_base
209  *
210  * Nodes, used to wrap elements stored in the hash table. A policy
211  * template parameter of class template _Hashtable controls whether
212  * nodes also store a hash code. In some cases (e.g. strings) this
213  * may be a performance win.
214  */
215  struct _Hash_node_base
216  {
217  _Hash_node_base* _M_nxt;
218 
219  _Hash_node_base() noexcept : _M_nxt() { }
220 
221  _Hash_node_base(_Hash_node_base* __next) noexcept : _M_nxt(__next) { }
222  };
223 
224  /**
225  * struct _Hash_node_value_base
226  *
227  * Node type with the value to store.
228  */
229  template<typename _Value>
230  struct _Hash_node_value_base
231  {
232  typedef _Value value_type;
233 
234  __gnu_cxx::__aligned_buffer<_Value> _M_storage;
235 
236  [[__gnu__::__always_inline__]]
237  _Value*
238  _M_valptr() noexcept
239  { return _M_storage._M_ptr(); }
240 
241  [[__gnu__::__always_inline__]]
242  const _Value*
243  _M_valptr() const noexcept
244  { return _M_storage._M_ptr(); }
245 
246  [[__gnu__::__always_inline__]]
247  _Value&
248  _M_v() noexcept
249  { return *_M_valptr(); }
250 
251  [[__gnu__::__always_inline__]]
252  const _Value&
253  _M_v() const noexcept
254  { return *_M_valptr(); }
255  };
256 
257  /**
258  * Primary template struct _Hash_node_code_cache.
259  */
260  template<bool _Cache_hash_code>
261  struct _Hash_node_code_cache
262  { };
263 
264  /**
265  * Specialization for node with cache, struct _Hash_node_code_cache.
266  */
267  template<>
268  struct _Hash_node_code_cache<true>
269  { std::size_t _M_hash_code; };
270 
271  template<typename _Value, bool _Cache_hash_code>
272  struct _Hash_node_value
273  : _Hash_node_value_base<_Value>
274  , _Hash_node_code_cache<_Cache_hash_code>
275  { };
276 
277  /**
278  * Primary template struct _Hash_node.
279  */
280  template<typename _Value, bool _Cache_hash_code>
281  struct _Hash_node
282  : _Hash_node_base
283  , _Hash_node_value<_Value, _Cache_hash_code>
284  {
285  _Hash_node*
286  _M_next() const noexcept
287  { return static_cast<_Hash_node*>(this->_M_nxt); }
288  };
289 
290  /// Base class for node iterators.
291  template<typename _Value, bool _Cache_hash_code>
292  struct _Node_iterator_base
293  {
294  using __node_type = _Hash_node<_Value, _Cache_hash_code>;
295 
296  __node_type* _M_cur;
297 
298  _Node_iterator_base() : _M_cur(nullptr) { }
299  _Node_iterator_base(__node_type* __p) noexcept
300  : _M_cur(__p) { }
301 
302  void
303  _M_incr() noexcept
304  { _M_cur = _M_cur->_M_next(); }
305 
306  friend bool
307  operator==(const _Node_iterator_base& __x, const _Node_iterator_base& __y)
308  noexcept
309  { return __x._M_cur == __y._M_cur; }
310 
311 #if __cpp_impl_three_way_comparison < 201907L
312  friend bool
313  operator!=(const _Node_iterator_base& __x, const _Node_iterator_base& __y)
314  noexcept
315  { return __x._M_cur != __y._M_cur; }
316 #endif
317  };
318 
319  /// Node iterators, used to iterate through all the hashtable.
320  template<typename _Value, bool __constant_iterators, bool __cache>
321  struct _Node_iterator
322  : public _Node_iterator_base<_Value, __cache>
323  {
324  private:
325  using __base_type = _Node_iterator_base<_Value, __cache>;
326  using __node_type = typename __base_type::__node_type;
327 
328  public:
329  typedef _Value value_type;
330  typedef std::ptrdiff_t difference_type;
331  typedef std::forward_iterator_tag iterator_category;
332 
333  using pointer = typename std::conditional<__constant_iterators,
334  const value_type*, value_type*>::type;
335 
336  using reference = typename std::conditional<__constant_iterators,
337  const value_type&, value_type&>::type;
338 
339  _Node_iterator() = default;
340 
341  explicit
342  _Node_iterator(__node_type* __p) noexcept
343  : __base_type(__p) { }
344 
345  reference
346  operator*() const noexcept
347  { return this->_M_cur->_M_v(); }
348 
349  pointer
350  operator->() const noexcept
351  { return this->_M_cur->_M_valptr(); }
352 
353  _Node_iterator&
354  operator++() noexcept
355  {
356  this->_M_incr();
357  return *this;
358  }
359 
360  _Node_iterator
361  operator++(int) noexcept
362  {
363  _Node_iterator __tmp(*this);
364  this->_M_incr();
365  return __tmp;
366  }
367  };
368 
369  /// Node const_iterators, used to iterate through all the hashtable.
370  template<typename _Value, bool __constant_iterators, bool __cache>
371  struct _Node_const_iterator
372  : public _Node_iterator_base<_Value, __cache>
373  {
374  private:
375  using __base_type = _Node_iterator_base<_Value, __cache>;
376  using __node_type = typename __base_type::__node_type;
377 
378  public:
379  typedef _Value value_type;
380  typedef std::ptrdiff_t difference_type;
381  typedef std::forward_iterator_tag iterator_category;
382 
383  typedef const value_type* pointer;
384  typedef const value_type& reference;
385 
386  _Node_const_iterator() = default;
387 
388  explicit
389  _Node_const_iterator(__node_type* __p) noexcept
390  : __base_type(__p) { }
391 
392  _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators,
393  __cache>& __x) noexcept
394  : __base_type(__x._M_cur) { }
395 
396  reference
397  operator*() const noexcept
398  { return this->_M_cur->_M_v(); }
399 
400  pointer
401  operator->() const noexcept
402  { return this->_M_cur->_M_valptr(); }
403 
404  _Node_const_iterator&
405  operator++() noexcept
406  {
407  this->_M_incr();
408  return *this;
409  }
410 
411  _Node_const_iterator
412  operator++(int) noexcept
413  {
414  _Node_const_iterator __tmp(*this);
415  this->_M_incr();
416  return __tmp;
417  }
418  };
419 
420  // Many of class template _Hashtable's template parameters are policy
421  // classes. These are defaults for the policies.
422 
423  /// Default range hashing function: use division to fold a large number
424  /// into the range [0, N).
425  struct _Mod_range_hashing
426  {
427  typedef std::size_t first_argument_type;
428  typedef std::size_t second_argument_type;
429  typedef std::size_t result_type;
430 
431  result_type
432  operator()(first_argument_type __num,
433  second_argument_type __den) const noexcept
434  { return __num % __den; }
435  };
436 
437  /// Default ranged hash function H. In principle it should be a
438  /// function object composed from objects of type H1 and H2 such that
439  /// h(k, N) = h2(h1(k), N), but that would mean making extra copies of
440  /// h1 and h2. So instead we'll just use a tag to tell class template
441  /// hashtable to do that composition.
442  struct _Default_ranged_hash { };
443 
444  /// Default value for rehash policy. Bucket size is (usually) the
445  /// smallest prime that keeps the load factor small enough.
446  struct _Prime_rehash_policy
447  {
448  using __has_load_factor = true_type;
449 
450  _Prime_rehash_policy(float __z = 1.0) noexcept
451  : _M_max_load_factor(__z), _M_next_resize(0) { }
452 
453  float
454  max_load_factor() const noexcept
455  { return _M_max_load_factor; }
456 
457  // Return a bucket size no smaller than n.
458  std::size_t
459  _M_next_bkt(std::size_t __n) const;
460 
461  // Return a bucket count appropriate for n elements
462  std::size_t
463  _M_bkt_for_elements(std::size_t __n) const
464  { return __builtin_ceil(__n / (double)_M_max_load_factor); }
465 
466  // __n_bkt is current bucket count, __n_elt is current element count,
467  // and __n_ins is number of elements to be inserted. Do we need to
468  // increase bucket count? If so, return make_pair(true, n), where n
469  // is the new bucket count. If not, return make_pair(false, 0).
471  _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
472  std::size_t __n_ins) const;
473 
474  typedef std::size_t _State;
475 
476  _State
477  _M_state() const
478  { return _M_next_resize; }
479 
480  void
481  _M_reset() noexcept
482  { _M_next_resize = 0; }
483 
484  void
485  _M_reset(_State __state)
486  { _M_next_resize = __state; }
487 
488  static const std::size_t _S_growth_factor = 2;
489 
490  float _M_max_load_factor;
491  mutable std::size_t _M_next_resize;
492  };
493 
494  /// Range hashing function assuming that second arg is a power of 2.
495  struct _Mask_range_hashing
496  {
497  typedef std::size_t first_argument_type;
498  typedef std::size_t second_argument_type;
499  typedef std::size_t result_type;
500 
501  result_type
502  operator()(first_argument_type __num,
503  second_argument_type __den) const noexcept
504  { return __num & (__den - 1); }
505  };
506 
507  /// Compute closest power of 2 not less than __n
508  inline std::size_t
509  __clp2(std::size_t __n) noexcept
510  {
512  // Equivalent to return __n ? std::bit_ceil(__n) : 0;
513  if (__n < 2)
514  return __n;
515  const unsigned __lz = sizeof(size_t) > sizeof(long)
516  ? __builtin_clzll(__n - 1ull)
517  : __builtin_clzl(__n - 1ul);
518  // Doing two shifts avoids undefined behaviour when __lz == 0.
519  return (size_t(1) << (__int_traits<size_t>::__digits - __lz - 1)) << 1;
520  }
521 
522  /// Rehash policy providing power of 2 bucket numbers. Avoids modulo
523  /// operations.
524  struct _Power2_rehash_policy
525  {
526  using __has_load_factor = true_type;
527 
528  _Power2_rehash_policy(float __z = 1.0) noexcept
529  : _M_max_load_factor(__z), _M_next_resize(0) { }
530 
531  float
532  max_load_factor() const noexcept
533  { return _M_max_load_factor; }
534 
535  // Return a bucket size no smaller than n (as long as n is not above the
536  // highest power of 2).
537  std::size_t
538  _M_next_bkt(std::size_t __n) noexcept
539  {
540  if (__n == 0)
541  // Special case on container 1st initialization with 0 bucket count
542  // hint. We keep _M_next_resize to 0 to make sure that next time we
543  // want to add an element allocation will take place.
544  return 1;
545 
546  const auto __max_width = std::min<size_t>(sizeof(size_t), 8);
547  const auto __max_bkt = size_t(1) << (__max_width * __CHAR_BIT__ - 1);
548  std::size_t __res = __clp2(__n);
549 
550  if (__res == 0)
551  __res = __max_bkt;
552  else if (__res == 1)
553  // If __res is 1 we force it to 2 to make sure there will be an
554  // allocation so that nothing need to be stored in the initial
555  // single bucket
556  __res = 2;
557 
558  if (__res == __max_bkt)
559  // Set next resize to the max value so that we never try to rehash again
560  // as we already reach the biggest possible bucket number.
561  // Note that it might result in max_load_factor not being respected.
562  _M_next_resize = size_t(-1);
563  else
564  _M_next_resize
565  = __builtin_floor(__res * (double)_M_max_load_factor);
566 
567  return __res;
568  }
569 
570  // Return a bucket count appropriate for n elements
571  std::size_t
572  _M_bkt_for_elements(std::size_t __n) const noexcept
573  { return __builtin_ceil(__n / (double)_M_max_load_factor); }
574 
575  // __n_bkt is current bucket count, __n_elt is current element count,
576  // and __n_ins is number of elements to be inserted. Do we need to
577  // increase bucket count? If so, return make_pair(true, n), where n
578  // is the new bucket count. If not, return make_pair(false, 0).
580  _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
581  std::size_t __n_ins) noexcept
582  {
583  if (__n_elt + __n_ins > _M_next_resize)
584  {
585  // If _M_next_resize is 0 it means that we have nothing allocated so
586  // far and that we start inserting elements. In this case we start
587  // with an initial bucket size of 11.
588  double __min_bkts
589  = std::max<std::size_t>(__n_elt + __n_ins, _M_next_resize ? 0 : 11)
590  / (double)_M_max_load_factor;
591  if (__min_bkts >= __n_bkt)
592  return { true,
593  _M_next_bkt(std::max<std::size_t>(__builtin_floor(__min_bkts) + 1,
594  __n_bkt * _S_growth_factor)) };
595 
596  _M_next_resize
597  = __builtin_floor(__n_bkt * (double)_M_max_load_factor);
598  return { false, 0 };
599  }
600  else
601  return { false, 0 };
602  }
603 
604  typedef std::size_t _State;
605 
606  _State
607  _M_state() const noexcept
608  { return _M_next_resize; }
609 
610  void
611  _M_reset() noexcept
612  { _M_next_resize = 0; }
613 
614  void
615  _M_reset(_State __state) noexcept
616  { _M_next_resize = __state; }
617 
618  static const std::size_t _S_growth_factor = 2;
619 
620  float _M_max_load_factor;
621  std::size_t _M_next_resize;
622  };
623 
624  // Base classes for std::_Hashtable. We define these base classes
625  // because in some cases we want to do different things depending on
626  // the value of a policy class. In some cases the policy class
627  // affects which member functions and nested typedefs are defined;
628  // we handle that by specializing base class templates. Several of
629  // the base class templates need to access other members of class
630  // template _Hashtable, so we use a variant of the "Curiously
631  // Recurring Template Pattern" (CRTP) technique.
632 
633  /**
634  * Primary class template _Map_base.
635  *
636  * If the hashtable has a value type of the form pair<T1, T2> and a
637  * key extraction policy (_ExtractKey) that returns the first part
638  * of the pair, the hashtable gets a mapped_type typedef. If it
639  * satisfies those criteria and also has unique keys, then it also
640  * gets an operator[].
641  */
642  template<typename _Key, typename _Value, typename _Alloc,
643  typename _ExtractKey, typename _Equal,
644  typename _Hash, typename _RangeHash, typename _Unused,
645  typename _RehashPolicy, typename _Traits,
646  bool _Unique_keys = _Traits::__unique_keys::value>
647  struct _Map_base { };
648 
649  /// Partial specialization, __unique_keys set to false.
650  template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
651  typename _Hash, typename _RangeHash, typename _Unused,
652  typename _RehashPolicy, typename _Traits>
653  struct _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
654  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
655  {
656  using mapped_type = typename std::tuple_element<1, _Pair>::type;
657  };
658 
659  /// Partial specialization, __unique_keys set to true.
660  template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
661  typename _Hash, typename _RangeHash, typename _Unused,
662  typename _RehashPolicy, typename _Traits>
663  struct _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
664  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>
665  {
666  private:
667  using __hashtable_base = _Hashtable_base<_Key, _Pair, _Select1st, _Equal,
668  _Hash, _RangeHash, _Unused,
669  _Traits>;
670 
671  using __hashtable = _Hashtable<_Key, _Pair, _Alloc, _Select1st, _Equal,
672  _Hash, _RangeHash,
673  _Unused, _RehashPolicy, _Traits>;
674 
675  using __hash_code = typename __hashtable_base::__hash_code;
676 
677  public:
678  using key_type = typename __hashtable_base::key_type;
679  using mapped_type = typename std::tuple_element<1, _Pair>::type;
680 
681  mapped_type&
682  operator[](const key_type& __k);
683 
684  mapped_type&
685  operator[](key_type&& __k);
686 
687  // _GLIBCXX_RESOLVE_LIB_DEFECTS
688  // DR 761. unordered_map needs an at() member function.
689  mapped_type&
690  at(const key_type& __k);
691 
692  const mapped_type&
693  at(const key_type& __k) const;
694  };
695 
696  template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
697  typename _Hash, typename _RangeHash, typename _Unused,
698  typename _RehashPolicy, typename _Traits>
699  auto
700  _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
701  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
702  operator[](const key_type& __k)
703  -> mapped_type&
704  {
705  __hashtable* __h = static_cast<__hashtable*>(this);
706  __hash_code __code = __h->_M_hash_code(__k);
707  std::size_t __bkt = __h->_M_bucket_index(__code);
708  if (auto __node = __h->_M_find_node(__bkt, __k, __code))
709  return __node->_M_v().second;
710 
711  typename __hashtable::_Scoped_node __node {
712  __h,
715  std::tuple<>()
716  };
717  auto __pos
718  = __h->_M_insert_unique_node(__bkt, __code, __node._M_node);
719  __node._M_node = nullptr;
720  return __pos->second;
721  }
722 
723  template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
724  typename _Hash, typename _RangeHash, typename _Unused,
725  typename _RehashPolicy, typename _Traits>
726  auto
727  _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
728  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
729  operator[](key_type&& __k)
730  -> mapped_type&
731  {
732  __hashtable* __h = static_cast<__hashtable*>(this);
733  __hash_code __code = __h->_M_hash_code(__k);
734  std::size_t __bkt = __h->_M_bucket_index(__code);
735  if (auto __node = __h->_M_find_node(__bkt, __k, __code))
736  return __node->_M_v().second;
737 
738  typename __hashtable::_Scoped_node __node {
739  __h,
742  std::tuple<>()
743  };
744  auto __pos
745  = __h->_M_insert_unique_node(__bkt, __code, __node._M_node);
746  __node._M_node = nullptr;
747  return __pos->second;
748  }
749 
750  template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
751  typename _Hash, typename _RangeHash, typename _Unused,
752  typename _RehashPolicy, typename _Traits>
753  auto
754  _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
755  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
756  at(const key_type& __k)
757  -> mapped_type&
758  {
759  __hashtable* __h = static_cast<__hashtable*>(this);
760  auto __ite = __h->find(__k);
761 
762  if (!__ite._M_cur)
763  __throw_out_of_range(__N("_Map_base::at"));
764  return __ite->second;
765  }
766 
767  template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
768  typename _Hash, typename _RangeHash, typename _Unused,
769  typename _RehashPolicy, typename _Traits>
770  auto
771  _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
772  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
773  at(const key_type& __k) const
774  -> const mapped_type&
775  {
776  const __hashtable* __h = static_cast<const __hashtable*>(this);
777  auto __ite = __h->find(__k);
778 
779  if (!__ite._M_cur)
780  __throw_out_of_range(__N("_Map_base::at"));
781  return __ite->second;
782  }
783 
784  /**
785  * Primary class template _Insert_base.
786  *
787  * Defines @c insert member functions appropriate to all _Hashtables.
788  */
789  template<typename _Key, typename _Value, typename _Alloc,
790  typename _ExtractKey, typename _Equal,
791  typename _Hash, typename _RangeHash, typename _Unused,
792  typename _RehashPolicy, typename _Traits>
793  struct _Insert_base
794  {
795  protected:
796  using __hashtable_base = _Hashtable_base<_Key, _Value, _ExtractKey,
797  _Equal, _Hash, _RangeHash,
798  _Unused, _Traits>;
799 
800  using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
801  _Hash, _RangeHash,
802  _Unused, _RehashPolicy, _Traits>;
803 
804  using __hash_cached = typename _Traits::__hash_cached;
805  using __constant_iterators = typename _Traits::__constant_iterators;
806 
807  using __hashtable_alloc = _Hashtable_alloc<
808  __alloc_rebind<_Alloc, _Hash_node<_Value,
809  __hash_cached::value>>>;
810 
811  using value_type = typename __hashtable_base::value_type;
812  using size_type = typename __hashtable_base::size_type;
813 
814  using __unique_keys = typename _Traits::__unique_keys;
815  using __node_alloc_type = typename __hashtable_alloc::__node_alloc_type;
816  using __node_gen_type = _AllocNode<__node_alloc_type>;
817 
818  __hashtable&
819  _M_conjure_hashtable()
820  { return *(static_cast<__hashtable*>(this)); }
821 
822  template<typename _InputIterator, typename _NodeGetter>
823  void
824  _M_insert_range(_InputIterator __first, _InputIterator __last,
825  const _NodeGetter&, true_type __uks);
826 
827  template<typename _InputIterator, typename _NodeGetter>
828  void
829  _M_insert_range(_InputIterator __first, _InputIterator __last,
830  const _NodeGetter&, false_type __uks);
831 
832  public:
833  using iterator = _Node_iterator<_Value, __constant_iterators::value,
834  __hash_cached::value>;
835 
836  using const_iterator = _Node_const_iterator<_Value, __constant_iterators::value,
837  __hash_cached::value>;
838 
839  using __ireturn_type = typename std::conditional<__unique_keys::value,
841  iterator>::type;
842 
843  __ireturn_type
844  insert(const value_type& __v)
845  {
846  __hashtable& __h = _M_conjure_hashtable();
847  __node_gen_type __node_gen(__h);
848  return __h._M_insert(__v, __node_gen, __unique_keys{});
849  }
850 
851  iterator
852  insert(const_iterator __hint, const value_type& __v)
853  {
854  __hashtable& __h = _M_conjure_hashtable();
855  __node_gen_type __node_gen(__h);
856  return __h._M_insert(__hint, __v, __node_gen, __unique_keys{});
857  }
858 
859  template<typename _KType, typename... _Args>
861  try_emplace(const_iterator, _KType&& __k, _Args&&... __args)
862  {
863  __hashtable& __h = _M_conjure_hashtable();
864  auto __code = __h._M_hash_code(__k);
865  std::size_t __bkt = __h._M_bucket_index(__code);
866  if (auto __node = __h._M_find_node(__bkt, __k, __code))
867  return { iterator(__node), false };
868 
869  typename __hashtable::_Scoped_node __node {
870  &__h,
872  std::forward_as_tuple(std::forward<_KType>(__k)),
873  std::forward_as_tuple(std::forward<_Args>(__args)...)
874  };
875  auto __it
876  = __h._M_insert_unique_node(__bkt, __code, __node._M_node);
877  __node._M_node = nullptr;
878  return { __it, true };
879  }
880 
881  void
882  insert(initializer_list<value_type> __l)
883  { this->insert(__l.begin(), __l.end()); }
884 
885  template<typename _InputIterator>
886  void
887  insert(_InputIterator __first, _InputIterator __last)
888  {
889  __hashtable& __h = _M_conjure_hashtable();
890  __node_gen_type __node_gen(__h);
891  return _M_insert_range(__first, __last, __node_gen, __unique_keys{});
892  }
893  };
894 
895  template<typename _Key, typename _Value, typename _Alloc,
896  typename _ExtractKey, typename _Equal,
897  typename _Hash, typename _RangeHash, typename _Unused,
898  typename _RehashPolicy, typename _Traits>
899  template<typename _InputIterator, typename _NodeGetter>
900  void
901  _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
902  _Hash, _RangeHash, _Unused,
903  _RehashPolicy, _Traits>::
904  _M_insert_range(_InputIterator __first, _InputIterator __last,
905  const _NodeGetter& __node_gen, true_type __uks)
906  {
907  __hashtable& __h = _M_conjure_hashtable();
908  for (; __first != __last; ++__first)
909  __h._M_insert(*__first, __node_gen, __uks);
910  }
911 
912  template<typename _Key, typename _Value, typename _Alloc,
913  typename _ExtractKey, typename _Equal,
914  typename _Hash, typename _RangeHash, typename _Unused,
915  typename _RehashPolicy, typename _Traits>
916  template<typename _InputIterator, typename _NodeGetter>
917  void
918  _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
919  _Hash, _RangeHash, _Unused,
920  _RehashPolicy, _Traits>::
921  _M_insert_range(_InputIterator __first, _InputIterator __last,
922  const _NodeGetter& __node_gen, false_type __uks)
923  {
924  using __rehash_type = typename __hashtable::__rehash_type;
925  using __rehash_state = typename __hashtable::__rehash_state;
926  using pair_type = std::pair<bool, std::size_t>;
927 
928  size_type __n_elt = __detail::__distance_fw(__first, __last);
929  if (__n_elt == 0)
930  return;
931 
932  __hashtable& __h = _M_conjure_hashtable();
933  __rehash_type& __rehash = __h._M_rehash_policy;
934  const __rehash_state& __saved_state = __rehash._M_state();
935  pair_type __do_rehash = __rehash._M_need_rehash(__h._M_bucket_count,
936  __h._M_element_count,
937  __n_elt);
938 
939  if (__do_rehash.first)
940  __h._M_rehash(__do_rehash.second, __saved_state);
941 
942  for (; __first != __last; ++__first)
943  __h._M_insert(*__first, __node_gen, __uks);
944  }
945 
946  /**
947  * Primary class template _Insert.
948  *
949  * Defines @c insert member functions that depend on _Hashtable policies,
950  * via partial specializations.
951  */
952  template<typename _Key, typename _Value, typename _Alloc,
953  typename _ExtractKey, typename _Equal,
954  typename _Hash, typename _RangeHash, typename _Unused,
955  typename _RehashPolicy, typename _Traits,
956  bool _Constant_iterators = _Traits::__constant_iterators::value>
957  struct _Insert;
958 
959  /// Specialization.
960  template<typename _Key, typename _Value, typename _Alloc,
961  typename _ExtractKey, typename _Equal,
962  typename _Hash, typename _RangeHash, typename _Unused,
963  typename _RehashPolicy, typename _Traits>
964  struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
965  _Hash, _RangeHash, _Unused,
966  _RehashPolicy, _Traits, true>
967  : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
968  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>
969  {
970  using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
971  _Equal, _Hash, _RangeHash, _Unused,
972  _RehashPolicy, _Traits>;
973 
974  using value_type = typename __base_type::value_type;
975  using iterator = typename __base_type::iterator;
976  using const_iterator = typename __base_type::const_iterator;
977  using __ireturn_type = typename __base_type::__ireturn_type;
978 
979  using __unique_keys = typename __base_type::__unique_keys;
980  using __hashtable = typename __base_type::__hashtable;
981  using __node_gen_type = typename __base_type::__node_gen_type;
982 
983  using __base_type::insert;
984 
985  __ireturn_type
986  insert(value_type&& __v)
987  {
988  __hashtable& __h = this->_M_conjure_hashtable();
989  __node_gen_type __node_gen(__h);
990  return __h._M_insert(std::move(__v), __node_gen, __unique_keys{});
991  }
992 
993  iterator
994  insert(const_iterator __hint, value_type&& __v)
995  {
996  __hashtable& __h = this->_M_conjure_hashtable();
997  __node_gen_type __node_gen(__h);
998  return __h._M_insert(__hint, std::move(__v), __node_gen,
999  __unique_keys{});
1000  }
1001  };
1002 
1003  /// Specialization.
1004  template<typename _Key, typename _Value, typename _Alloc,
1005  typename _ExtractKey, typename _Equal,
1006  typename _Hash, typename _RangeHash, typename _Unused,
1007  typename _RehashPolicy, typename _Traits>
1008  struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1009  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
1010  : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1011  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>
1012  {
1013  using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
1014  _Equal, _Hash, _RangeHash, _Unused,
1015  _RehashPolicy, _Traits>;
1016  using value_type = typename __base_type::value_type;
1017  using iterator = typename __base_type::iterator;
1018  using const_iterator = typename __base_type::const_iterator;
1019 
1020  using __unique_keys = typename __base_type::__unique_keys;
1021  using __hashtable = typename __base_type::__hashtable;
1022  using __ireturn_type = typename __base_type::__ireturn_type;
1023 
1024  using __base_type::insert;
1025 
1026  template<typename _Pair>
1028 
1029  template<typename _Pair>
1030  using _IFcons = std::enable_if<__is_cons<_Pair>::value>;
1031 
1032  template<typename _Pair>
1033  using _IFconsp = typename _IFcons<_Pair>::type;
1034 
1035  template<typename _Pair, typename = _IFconsp<_Pair>>
1036  __ireturn_type
1037  insert(_Pair&& __v)
1038  {
1039  __hashtable& __h = this->_M_conjure_hashtable();
1040  return __h._M_emplace(__unique_keys{}, std::forward<_Pair>(__v));
1041  }
1042 
1043  template<typename _Pair, typename = _IFconsp<_Pair>>
1044  iterator
1045  insert(const_iterator __hint, _Pair&& __v)
1046  {
1047  __hashtable& __h = this->_M_conjure_hashtable();
1048  return __h._M_emplace(__hint, __unique_keys{},
1049  std::forward<_Pair>(__v));
1050  }
1051  };
1052 
1053  template<typename _Policy>
1054  using __has_load_factor = typename _Policy::__has_load_factor;
1055 
1056  /**
1057  * Primary class template _Rehash_base.
1058  *
1059  * Give hashtable the max_load_factor functions and reserve iff the
1060  * rehash policy supports it.
1061  */
1062  template<typename _Key, typename _Value, typename _Alloc,
1063  typename _ExtractKey, typename _Equal,
1064  typename _Hash, typename _RangeHash, typename _Unused,
1065  typename _RehashPolicy, typename _Traits,
1066  typename =
1067  __detected_or_t<false_type, __has_load_factor, _RehashPolicy>>
1068  struct _Rehash_base;
1069 
1070  /// Specialization when rehash policy doesn't provide load factor management.
1071  template<typename _Key, typename _Value, typename _Alloc,
1072  typename _ExtractKey, typename _Equal,
1073  typename _Hash, typename _RangeHash, typename _Unused,
1074  typename _RehashPolicy, typename _Traits>
1075  struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1076  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits,
1077  false_type /* Has load factor */>
1078  {
1079  };
1080 
1081  /// Specialization when rehash policy provide load factor management.
1082  template<typename _Key, typename _Value, typename _Alloc,
1083  typename _ExtractKey, typename _Equal,
1084  typename _Hash, typename _RangeHash, typename _Unused,
1085  typename _RehashPolicy, typename _Traits>
1086  struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1087  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits,
1088  true_type /* Has load factor */>
1089  {
1090  using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
1091  _Equal, _Hash, _RangeHash, _Unused,
1092  _RehashPolicy, _Traits>;
1093 
1094  float
1095  max_load_factor() const noexcept
1096  {
1097  const __hashtable* __this = static_cast<const __hashtable*>(this);
1098  return __this->__rehash_policy().max_load_factor();
1099  }
1100 
1101  void
1102  max_load_factor(float __z)
1103  {
1104  __hashtable* __this = static_cast<__hashtable*>(this);
1105  __this->__rehash_policy(_RehashPolicy(__z));
1106  }
1107 
1108  void
1109  reserve(std::size_t __n)
1110  {
1111  __hashtable* __this = static_cast<__hashtable*>(this);
1112  __this->rehash(__this->__rehash_policy()._M_bkt_for_elements(__n));
1113  }
1114  };
1115 
1116  /**
1117  * Primary class template _Hashtable_ebo_helper.
1118  *
1119  * Helper class using EBO when it is not forbidden (the type is not
1120  * final) and when it is worth it (the type is empty.)
1121  */
1122  template<int _Nm, typename _Tp,
1123  bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
1124  struct _Hashtable_ebo_helper;
1125 
1126  /// Specialization using EBO.
1127  template<int _Nm, typename _Tp>
1128  struct _Hashtable_ebo_helper<_Nm, _Tp, true>
1129  : private _Tp
1130  {
1131  _Hashtable_ebo_helper() noexcept(noexcept(_Tp())) : _Tp() { }
1132 
1133  template<typename _OtherTp>
1134  _Hashtable_ebo_helper(_OtherTp&& __tp)
1135  : _Tp(std::forward<_OtherTp>(__tp))
1136  { }
1137 
1138  const _Tp& _M_cget() const { return static_cast<const _Tp&>(*this); }
1139  _Tp& _M_get() { return static_cast<_Tp&>(*this); }
1140  };
1141 
1142  /// Specialization not using EBO.
1143  template<int _Nm, typename _Tp>
1144  struct _Hashtable_ebo_helper<_Nm, _Tp, false>
1145  {
1146  _Hashtable_ebo_helper() = default;
1147 
1148  template<typename _OtherTp>
1149  _Hashtable_ebo_helper(_OtherTp&& __tp)
1150  : _M_tp(std::forward<_OtherTp>(__tp))
1151  { }
1152 
1153  const _Tp& _M_cget() const { return _M_tp; }
1154  _Tp& _M_get() { return _M_tp; }
1155 
1156  private:
1157  _Tp _M_tp{};
1158  };
1159 
1160  /**
1161  * Primary class template _Local_iterator_base.
1162  *
1163  * Base class for local iterators, used to iterate within a bucket
1164  * but not between buckets.
1165  */
1166  template<typename _Key, typename _Value, typename _ExtractKey,
1167  typename _Hash, typename _RangeHash, typename _Unused,
1168  bool __cache_hash_code>
1169  struct _Local_iterator_base;
1170 
1171  /**
1172  * Primary class template _Hash_code_base.
1173  *
1174  * Encapsulates two policy issues that aren't quite orthogonal.
1175  * (1) the difference between using a ranged hash function and using
1176  * the combination of a hash function and a range-hashing function.
1177  * In the former case we don't have such things as hash codes, so
1178  * we have a dummy type as placeholder.
1179  * (2) Whether or not we cache hash codes. Caching hash codes is
1180  * meaningless if we have a ranged hash function.
1181  *
1182  * We also put the key extraction objects here, for convenience.
1183  * Each specialization derives from one or more of the template
1184  * parameters to benefit from Ebo. This is important as this type
1185  * is inherited in some cases by the _Local_iterator_base type used
1186  * to implement local_iterator and const_local_iterator. As with
1187  * any iterator type we prefer to make it as small as possible.
1188  */
1189  template<typename _Key, typename _Value, typename _ExtractKey,
1190  typename _Hash, typename _RangeHash, typename _Unused,
1191  bool __cache_hash_code>
1192  struct _Hash_code_base
1193  : private _Hashtable_ebo_helper<1, _Hash>
1194  {
1195  private:
1196  using __ebo_hash = _Hashtable_ebo_helper<1, _Hash>;
1197 
1198  // Gives the local iterator implementation access to _M_bucket_index().
1199  friend struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1200  _Hash, _RangeHash, _Unused, false>;
1201 
1202  public:
1203  typedef _Hash hasher;
1204 
1205  hasher
1206  hash_function() const
1207  { return _M_hash(); }
1208 
1209  protected:
1210  typedef std::size_t __hash_code;
1211 
1212  // We need the default constructor for the local iterators and _Hashtable
1213  // default constructor.
1214  _Hash_code_base() = default;
1215 
1216  _Hash_code_base(const _Hash& __hash) : __ebo_hash(__hash) { }
1217 
1218  __hash_code
1219  _M_hash_code(const _Key& __k) const
1220  {
1221  static_assert(__is_invocable<const _Hash&, const _Key&>{},
1222  "hash function must be invocable with an argument of key type");
1223  return _M_hash()(__k);
1224  }
1225 
1226  template<typename _Kt>
1227  __hash_code
1228  _M_hash_code_tr(const _Kt& __k) const
1229  {
1230  static_assert(__is_invocable<const _Hash&, const _Kt&>{},
1231  "hash function must be invocable with an argument of key type");
1232  return _M_hash()(__k);
1233  }
1234 
1235  std::size_t
1236  _M_bucket_index(__hash_code __c, std::size_t __bkt_count) const
1237  { return _RangeHash{}(__c, __bkt_count); }
1238 
1239  std::size_t
1240  _M_bucket_index(const _Hash_node_value<_Value, false>& __n,
1241  std::size_t __bkt_count) const
1242  noexcept( noexcept(declval<const _Hash&>()(declval<const _Key&>()))
1243  && noexcept(declval<const _RangeHash&>()((__hash_code)0,
1244  (std::size_t)0)) )
1245  {
1246  return _RangeHash{}(_M_hash_code(_ExtractKey{}(__n._M_v())),
1247  __bkt_count);
1248  }
1249 
1250  std::size_t
1251  _M_bucket_index(const _Hash_node_value<_Value, true>& __n,
1252  std::size_t __bkt_count) const
1253  noexcept( noexcept(declval<const _RangeHash&>()((__hash_code)0,
1254  (std::size_t)0)) )
1255  { return _RangeHash{}(__n._M_hash_code, __bkt_count); }
1256 
1257  void
1258  _M_store_code(_Hash_node_code_cache<false>&, __hash_code) const
1259  { }
1260 
1261  void
1262  _M_copy_code(_Hash_node_code_cache<false>&,
1263  const _Hash_node_code_cache<false>&) const
1264  { }
1265 
1266  void
1267  _M_store_code(_Hash_node_code_cache<true>& __n, __hash_code __c) const
1268  { __n._M_hash_code = __c; }
1269 
1270  void
1271  _M_copy_code(_Hash_node_code_cache<true>& __to,
1272  const _Hash_node_code_cache<true>& __from) const
1273  { __to._M_hash_code = __from._M_hash_code; }
1274 
1275  void
1276  _M_swap(_Hash_code_base& __x)
1277  { std::swap(__ebo_hash::_M_get(), __x.__ebo_hash::_M_get()); }
1278 
1279  const _Hash&
1280  _M_hash() const { return __ebo_hash::_M_cget(); }
1281  };
1282 
1283  /// Partial specialization used when nodes contain a cached hash code.
1284  template<typename _Key, typename _Value, typename _ExtractKey,
1285  typename _Hash, typename _RangeHash, typename _Unused>
1286  struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1287  _Hash, _RangeHash, _Unused, true>
1288  : public _Node_iterator_base<_Value, true>
1289  {
1290  protected:
1291  using __base_node_iter = _Node_iterator_base<_Value, true>;
1292  using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1293  _Hash, _RangeHash, _Unused, true>;
1294 
1295  _Local_iterator_base() = default;
1296  _Local_iterator_base(const __hash_code_base&,
1297  _Hash_node<_Value, true>* __p,
1298  std::size_t __bkt, std::size_t __bkt_count)
1299  : __base_node_iter(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
1300  { }
1301 
1302  void
1303  _M_incr()
1304  {
1305  __base_node_iter::_M_incr();
1306  if (this->_M_cur)
1307  {
1308  std::size_t __bkt
1309  = _RangeHash{}(this->_M_cur->_M_hash_code, _M_bucket_count);
1310  if (__bkt != _M_bucket)
1311  this->_M_cur = nullptr;
1312  }
1313  }
1314 
1315  std::size_t _M_bucket;
1316  std::size_t _M_bucket_count;
1317 
1318  public:
1319  std::size_t
1320  _M_get_bucket() const { return _M_bucket; } // for debug mode
1321  };
1322 
1323  // Uninitialized storage for a _Hash_code_base.
1324  // This type is DefaultConstructible and Assignable even if the
1325  // _Hash_code_base type isn't, so that _Local_iterator_base<..., false>
1326  // can be DefaultConstructible and Assignable.
1327  template<typename _Tp, bool _IsEmpty = std::is_empty<_Tp>::value>
1328  struct _Hash_code_storage
1329  {
1330  __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
1331 
1332  _Tp*
1333  _M_h() { return _M_storage._M_ptr(); }
1334 
1335  const _Tp*
1336  _M_h() const { return _M_storage._M_ptr(); }
1337  };
1338 
1339  // Empty partial specialization for empty _Hash_code_base types.
1340  template<typename _Tp>
1341  struct _Hash_code_storage<_Tp, true>
1342  {
1343  static_assert( std::is_empty<_Tp>::value, "Type must be empty" );
1344 
1345  // As _Tp is an empty type there will be no bytes written/read through
1346  // the cast pointer, so no strict-aliasing violation.
1347  _Tp*
1348  _M_h() { return reinterpret_cast<_Tp*>(this); }
1349 
1350  const _Tp*
1351  _M_h() const { return reinterpret_cast<const _Tp*>(this); }
1352  };
1353 
1354  template<typename _Key, typename _Value, typename _ExtractKey,
1355  typename _Hash, typename _RangeHash, typename _Unused>
1356  using __hash_code_for_local_iter
1357  = _Hash_code_storage<_Hash_code_base<_Key, _Value, _ExtractKey,
1358  _Hash, _RangeHash, _Unused, false>>;
1359 
1360  // Partial specialization used when hash codes are not cached
1361  template<typename _Key, typename _Value, typename _ExtractKey,
1362  typename _Hash, typename _RangeHash, typename _Unused>
1363  struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1364  _Hash, _RangeHash, _Unused, false>
1365  : __hash_code_for_local_iter<_Key, _Value, _ExtractKey, _Hash, _RangeHash,
1366  _Unused>
1367  , _Node_iterator_base<_Value, false>
1368  {
1369  protected:
1370  using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1371  _Hash, _RangeHash, _Unused, false>;
1372  using __node_iter_base = _Node_iterator_base<_Value, false>;
1373 
1374  _Local_iterator_base() : _M_bucket_count(-1) { }
1375 
1376  _Local_iterator_base(const __hash_code_base& __base,
1377  _Hash_node<_Value, false>* __p,
1378  std::size_t __bkt, std::size_t __bkt_count)
1379  : __node_iter_base(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
1380  { _M_init(__base); }
1381 
1382  ~_Local_iterator_base()
1383  {
1384  if (_M_bucket_count != size_t(-1))
1385  _M_destroy();
1386  }
1387 
1388  _Local_iterator_base(const _Local_iterator_base& __iter)
1389  : __node_iter_base(__iter._M_cur), _M_bucket(__iter._M_bucket)
1390  , _M_bucket_count(__iter._M_bucket_count)
1391  {
1392  if (_M_bucket_count != size_t(-1))
1393  _M_init(*__iter._M_h());
1394  }
1395 
1396  _Local_iterator_base&
1397  operator=(const _Local_iterator_base& __iter)
1398  {
1399  if (_M_bucket_count != -1)
1400  _M_destroy();
1401  this->_M_cur = __iter._M_cur;
1402  _M_bucket = __iter._M_bucket;
1403  _M_bucket_count = __iter._M_bucket_count;
1404  if (_M_bucket_count != -1)
1405  _M_init(*__iter._M_h());
1406  return *this;
1407  }
1408 
1409  void
1410  _M_incr()
1411  {
1412  __node_iter_base::_M_incr();
1413  if (this->_M_cur)
1414  {
1415  std::size_t __bkt = this->_M_h()->_M_bucket_index(*this->_M_cur,
1416  _M_bucket_count);
1417  if (__bkt != _M_bucket)
1418  this->_M_cur = nullptr;
1419  }
1420  }
1421 
1422  std::size_t _M_bucket;
1423  std::size_t _M_bucket_count;
1424 
1425  void
1426  _M_init(const __hash_code_base& __base)
1427  { ::new(this->_M_h()) __hash_code_base(__base); }
1428 
1429  void
1430  _M_destroy() { this->_M_h()->~__hash_code_base(); }
1431 
1432  public:
1433  std::size_t
1434  _M_get_bucket() const { return _M_bucket; } // for debug mode
1435  };
1436 
1437  /// local iterators
1438  template<typename _Key, typename _Value, typename _ExtractKey,
1439  typename _Hash, typename _RangeHash, typename _Unused,
1440  bool __constant_iterators, bool __cache>
1441  struct _Local_iterator
1442  : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1443  _Hash, _RangeHash, _Unused, __cache>
1444  {
1445  private:
1446  using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1447  _Hash, _RangeHash, _Unused, __cache>;
1448  using __hash_code_base = typename __base_type::__hash_code_base;
1449 
1450  public:
1451  typedef _Value value_type;
1452  typedef typename std::conditional<__constant_iterators,
1453  const value_type*, value_type*>::type
1454  pointer;
1455  typedef typename std::conditional<__constant_iterators,
1456  const value_type&, value_type&>::type
1457  reference;
1458  typedef std::ptrdiff_t difference_type;
1459  typedef std::forward_iterator_tag iterator_category;
1460 
1461  _Local_iterator() = default;
1462 
1463  _Local_iterator(const __hash_code_base& __base,
1464  _Hash_node<_Value, __cache>* __n,
1465  std::size_t __bkt, std::size_t __bkt_count)
1466  : __base_type(__base, __n, __bkt, __bkt_count)
1467  { }
1468 
1469  reference
1470  operator*() const
1471  { return this->_M_cur->_M_v(); }
1472 
1473  pointer
1474  operator->() const
1475  { return this->_M_cur->_M_valptr(); }
1476 
1477  _Local_iterator&
1478  operator++()
1479  {
1480  this->_M_incr();
1481  return *this;
1482  }
1483 
1484  _Local_iterator
1485  operator++(int)
1486  {
1487  _Local_iterator __tmp(*this);
1488  this->_M_incr();
1489  return __tmp;
1490  }
1491  };
1492 
1493  /// local const_iterators
1494  template<typename _Key, typename _Value, typename _ExtractKey,
1495  typename _Hash, typename _RangeHash, typename _Unused,
1496  bool __constant_iterators, bool __cache>
1497  struct _Local_const_iterator
1498  : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1499  _Hash, _RangeHash, _Unused, __cache>
1500  {
1501  private:
1502  using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1503  _Hash, _RangeHash, _Unused, __cache>;
1504  using __hash_code_base = typename __base_type::__hash_code_base;
1505 
1506  public:
1507  typedef _Value value_type;
1508  typedef const value_type* pointer;
1509  typedef const value_type& reference;
1510  typedef std::ptrdiff_t difference_type;
1511  typedef std::forward_iterator_tag iterator_category;
1512 
1513  _Local_const_iterator() = default;
1514 
1515  _Local_const_iterator(const __hash_code_base& __base,
1516  _Hash_node<_Value, __cache>* __n,
1517  std::size_t __bkt, std::size_t __bkt_count)
1518  : __base_type(__base, __n, __bkt, __bkt_count)
1519  { }
1520 
1521  _Local_const_iterator(const _Local_iterator<_Key, _Value, _ExtractKey,
1522  _Hash, _RangeHash, _Unused,
1523  __constant_iterators,
1524  __cache>& __x)
1525  : __base_type(__x)
1526  { }
1527 
1528  reference
1529  operator*() const
1530  { return this->_M_cur->_M_v(); }
1531 
1532  pointer
1533  operator->() const
1534  { return this->_M_cur->_M_valptr(); }
1535 
1536  _Local_const_iterator&
1537  operator++()
1538  {
1539  this->_M_incr();
1540  return *this;
1541  }
1542 
1543  _Local_const_iterator
1544  operator++(int)
1545  {
1546  _Local_const_iterator __tmp(*this);
1547  this->_M_incr();
1548  return __tmp;
1549  }
1550  };
1551 
1552  /**
1553  * Primary class template _Hashtable_base.
1554  *
1555  * Helper class adding management of _Equal functor to
1556  * _Hash_code_base type.
1557  *
1558  * Base class templates are:
1559  * - __detail::_Hash_code_base
1560  * - __detail::_Hashtable_ebo_helper
1561  */
1562  template<typename _Key, typename _Value, typename _ExtractKey,
1563  typename _Equal, typename _Hash, typename _RangeHash,
1564  typename _Unused, typename _Traits>
1565  struct _Hashtable_base
1566  : public _Hash_code_base<_Key, _Value, _ExtractKey, _Hash, _RangeHash,
1567  _Unused, _Traits::__hash_cached::value>,
1568  private _Hashtable_ebo_helper<0, _Equal>
1569  {
1570  public:
1571  typedef _Key key_type;
1572  typedef _Value value_type;
1573  typedef _Equal key_equal;
1574  typedef std::size_t size_type;
1575  typedef std::ptrdiff_t difference_type;
1576 
1577  using __traits_type = _Traits;
1578  using __hash_cached = typename __traits_type::__hash_cached;
1579 
1580  using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1581  _Hash, _RangeHash, _Unused,
1582  __hash_cached::value>;
1583 
1584  using __hash_code = typename __hash_code_base::__hash_code;
1585 
1586  private:
1587  using _EqualEBO = _Hashtable_ebo_helper<0, _Equal>;
1588 
1589  static bool
1590  _S_equals(__hash_code, const _Hash_node_code_cache<false>&)
1591  { return true; }
1592 
1593  static bool
1594  _S_node_equals(const _Hash_node_code_cache<false>&,
1595  const _Hash_node_code_cache<false>&)
1596  { return true; }
1597 
1598  static bool
1599  _S_equals(__hash_code __c, const _Hash_node_code_cache<true>& __n)
1600  { return __c == __n._M_hash_code; }
1601 
1602  static bool
1603  _S_node_equals(const _Hash_node_code_cache<true>& __lhn,
1604  const _Hash_node_code_cache<true>& __rhn)
1605  { return __lhn._M_hash_code == __rhn._M_hash_code; }
1606 
1607  protected:
1608  _Hashtable_base() = default;
1609 
1610  _Hashtable_base(const _Hash& __hash, const _Equal& __eq)
1611  : __hash_code_base(__hash), _EqualEBO(__eq)
1612  { }
1613 
1614  bool
1615  _M_equals(const _Key& __k, __hash_code __c,
1616  const _Hash_node_value<_Value, __hash_cached::value>& __n) const
1617  {
1618  static_assert(__is_invocable<const _Equal&, const _Key&, const _Key&>{},
1619  "key equality predicate must be invocable with two arguments of "
1620  "key type");
1621  return _S_equals(__c, __n) && _M_eq()(__k, _ExtractKey{}(__n._M_v()));
1622  }
1623 
1624  template<typename _Kt>
1625  bool
1626  _M_equals_tr(const _Kt& __k, __hash_code __c,
1627  const _Hash_node_value<_Value,
1628  __hash_cached::value>& __n) const
1629  {
1630  static_assert(
1631  __is_invocable<const _Equal&, const _Kt&, const _Key&>{},
1632  "key equality predicate must be invocable with two arguments of "
1633  "key type");
1634  return _S_equals(__c, __n) && _M_eq()(__k, _ExtractKey{}(__n._M_v()));
1635  }
1636 
1637  bool
1638  _M_node_equals(
1639  const _Hash_node_value<_Value, __hash_cached::value>& __lhn,
1640  const _Hash_node_value<_Value, __hash_cached::value>& __rhn) const
1641  {
1642  return _S_node_equals(__lhn, __rhn)
1643  && _M_eq()(_ExtractKey{}(__lhn._M_v()), _ExtractKey{}(__rhn._M_v()));
1644  }
1645 
1646  void
1647  _M_swap(_Hashtable_base& __x)
1648  {
1649  __hash_code_base::_M_swap(__x);
1650  std::swap(_EqualEBO::_M_get(), __x._EqualEBO::_M_get());
1651  }
1652 
1653  const _Equal&
1654  _M_eq() const { return _EqualEBO::_M_cget(); }
1655  };
1656 
1657  /**
1658  * Primary class template _Equality.
1659  *
1660  * This is for implementing equality comparison for unordered
1661  * containers, per N3068, by John Lakos and Pablo Halpern.
1662  * Algorithmically, we follow closely the reference implementations
1663  * therein.
1664  */
1665  template<typename _Key, typename _Value, typename _Alloc,
1666  typename _ExtractKey, typename _Equal,
1667  typename _Hash, typename _RangeHash, typename _Unused,
1668  typename _RehashPolicy, typename _Traits,
1669  bool _Unique_keys = _Traits::__unique_keys::value>
1670  struct _Equality;
1671 
1672  /// unordered_map and unordered_set specializations.
1673  template<typename _Key, typename _Value, typename _Alloc,
1674  typename _ExtractKey, typename _Equal,
1675  typename _Hash, typename _RangeHash, typename _Unused,
1676  typename _RehashPolicy, typename _Traits>
1677  struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1678  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>
1679  {
1680  using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1681  _Hash, _RangeHash, _Unused,
1682  _RehashPolicy, _Traits>;
1683 
1684  bool
1685  _M_equal(const __hashtable&) const;
1686  };
1687 
1688  template<typename _Key, typename _Value, typename _Alloc,
1689  typename _ExtractKey, typename _Equal,
1690  typename _Hash, typename _RangeHash, typename _Unused,
1691  typename _RehashPolicy, typename _Traits>
1692  bool
1693  _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1694  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
1695  _M_equal(const __hashtable& __other) const
1696  {
1697  using __node_type = typename __hashtable::__node_type;
1698  const __hashtable* __this = static_cast<const __hashtable*>(this);
1699  if (__this->size() != __other.size())
1700  return false;
1701 
1702  for (auto __itx = __this->begin(); __itx != __this->end(); ++__itx)
1703  {
1704  std::size_t __ybkt = __other._M_bucket_index(*__itx._M_cur);
1705  auto __prev_n = __other._M_buckets[__ybkt];
1706  if (!__prev_n)
1707  return false;
1708 
1709  for (__node_type* __n = static_cast<__node_type*>(__prev_n->_M_nxt);;
1710  __n = __n->_M_next())
1711  {
1712  if (__n->_M_v() == *__itx)
1713  break;
1714 
1715  if (!__n->_M_nxt
1716  || __other._M_bucket_index(*__n->_M_next()) != __ybkt)
1717  return false;
1718  }
1719  }
1720 
1721  return true;
1722  }
1723 
1724  /// unordered_multiset and unordered_multimap specializations.
1725  template<typename _Key, typename _Value, typename _Alloc,
1726  typename _ExtractKey, typename _Equal,
1727  typename _Hash, typename _RangeHash, typename _Unused,
1728  typename _RehashPolicy, typename _Traits>
1729  struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1730  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
1731  {
1732  using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1733  _Hash, _RangeHash, _Unused,
1734  _RehashPolicy, _Traits>;
1735 
1736  bool
1737  _M_equal(const __hashtable&) const;
1738  };
1739 
1740  template<typename _Key, typename _Value, typename _Alloc,
1741  typename _ExtractKey, typename _Equal,
1742  typename _Hash, typename _RangeHash, typename _Unused,
1743  typename _RehashPolicy, typename _Traits>
1744  bool
1745  _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1746  _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>::
1747  _M_equal(const __hashtable& __other) const
1748  {
1749  using __node_type = typename __hashtable::__node_type;
1750  const __hashtable* __this = static_cast<const __hashtable*>(this);
1751  if (__this->size() != __other.size())
1752  return false;
1753 
1754  for (auto __itx = __this->begin(); __itx != __this->end();)
1755  {
1756  std::size_t __x_count = 1;
1757  auto __itx_end = __itx;
1758  for (++__itx_end; __itx_end != __this->end()
1759  && __this->key_eq()(_ExtractKey{}(*__itx),
1760  _ExtractKey{}(*__itx_end));
1761  ++__itx_end)
1762  ++__x_count;
1763 
1764  std::size_t __ybkt = __other._M_bucket_index(*__itx._M_cur);
1765  auto __y_prev_n = __other._M_buckets[__ybkt];
1766  if (!__y_prev_n)
1767  return false;
1768 
1769  __node_type* __y_n = static_cast<__node_type*>(__y_prev_n->_M_nxt);
1770  for (;;)
1771  {
1772  if (__this->key_eq()(_ExtractKey{}(__y_n->_M_v()),
1773  _ExtractKey{}(*__itx)))
1774  break;
1775 
1776  auto __y_ref_n = __y_n;
1777  for (__y_n = __y_n->_M_next(); __y_n; __y_n = __y_n->_M_next())
1778  if (!__other._M_node_equals(*__y_ref_n, *__y_n))
1779  break;
1780 
1781  if (!__y_n || __other._M_bucket_index(*__y_n) != __ybkt)
1782  return false;
1783  }
1784 
1785  typename __hashtable::const_iterator __ity(__y_n);
1786  for (auto __ity_end = __ity; __ity_end != __other.end(); ++__ity_end)
1787  if (--__x_count == 0)
1788  break;
1789 
1790  if (__x_count != 0)
1791  return false;
1792 
1793  if (!std::is_permutation(__itx, __itx_end, __ity))
1794  return false;
1795 
1796  __itx = __itx_end;
1797  }
1798  return true;
1799  }
1800 
1801  /**
1802  * This type deals with all allocation and keeps an allocator instance
1803  * through inheritance to benefit from EBO when possible.
1804  */
1805  template<typename _NodeAlloc>
1806  struct _Hashtable_alloc : private _Hashtable_ebo_helper<0, _NodeAlloc>
1807  {
1808  private:
1809  using __ebo_node_alloc = _Hashtable_ebo_helper<0, _NodeAlloc>;
1810  public:
1811  using __node_type = typename _NodeAlloc::value_type;
1812  using __node_alloc_type = _NodeAlloc;
1813  // Use __gnu_cxx to benefit from _S_always_equal and al.
1814  using __node_alloc_traits = __gnu_cxx::__alloc_traits<__node_alloc_type>;
1815 
1816  using __value_alloc_traits = typename __node_alloc_traits::template
1817  rebind_traits<typename __node_type::value_type>;
1818 
1819  using __node_ptr = __node_type*;
1820  using __node_base = _Hash_node_base;
1821  using __node_base_ptr = __node_base*;
1822  using __buckets_alloc_type =
1823  __alloc_rebind<__node_alloc_type, __node_base_ptr>;
1824  using __buckets_alloc_traits = std::allocator_traits<__buckets_alloc_type>;
1825  using __buckets_ptr = __node_base_ptr*;
1826 
1827  _Hashtable_alloc() = default;
1828  _Hashtable_alloc(const _Hashtable_alloc&) = default;
1829  _Hashtable_alloc(_Hashtable_alloc&&) = default;
1830 
1831  template<typename _Alloc>
1832  _Hashtable_alloc(_Alloc&& __a)
1833  : __ebo_node_alloc(std::forward<_Alloc>(__a))
1834  { }
1835 
1836  __node_alloc_type&
1837  _M_node_allocator()
1838  { return __ebo_node_alloc::_M_get(); }
1839 
1840  const __node_alloc_type&
1841  _M_node_allocator() const
1842  { return __ebo_node_alloc::_M_cget(); }
1843 
1844  // Allocate a node and construct an element within it.
1845  template<typename... _Args>
1846  __node_ptr
1847  _M_allocate_node(_Args&&... __args);
1848 
1849  // Destroy the element within a node and deallocate the node.
1850  void
1851  _M_deallocate_node(__node_ptr __n);
1852 
1853  // Deallocate a node.
1854  void
1855  _M_deallocate_node_ptr(__node_ptr __n);
1856 
1857  // Deallocate the linked list of nodes pointed to by __n.
1858  // The elements within the nodes are destroyed.
1859  void
1860  _M_deallocate_nodes(__node_ptr __n);
1861 
1862  __buckets_ptr
1863  _M_allocate_buckets(std::size_t __bkt_count);
1864 
1865  void
1866  _M_deallocate_buckets(__buckets_ptr, std::size_t __bkt_count);
1867  };
1868 
1869  // Definitions of class template _Hashtable_alloc's out-of-line member
1870  // functions.
1871  template<typename _NodeAlloc>
1872  template<typename... _Args>
1873  auto
1874  _Hashtable_alloc<_NodeAlloc>::_M_allocate_node(_Args&&... __args)
1875  -> __node_ptr
1876  {
1877  auto __nptr = __node_alloc_traits::allocate(_M_node_allocator(), 1);
1878  __node_ptr __n = std::__to_address(__nptr);
1879  __try
1880  {
1881  ::new ((void*)__n) __node_type;
1882  __node_alloc_traits::construct(_M_node_allocator(),
1883  __n->_M_valptr(),
1884  std::forward<_Args>(__args)...);
1885  return __n;
1886  }
1887  __catch(...)
1888  {
1889  __node_alloc_traits::deallocate(_M_node_allocator(), __nptr, 1);
1890  __throw_exception_again;
1891  }
1892  }
1893 
1894  template<typename _NodeAlloc>
1895  void
1896  _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node(__node_ptr __n)
1897  {
1898  __node_alloc_traits::destroy(_M_node_allocator(), __n->_M_valptr());
1899  _M_deallocate_node_ptr(__n);
1900  }
1901 
1902  template<typename _NodeAlloc>
1903  void
1904  _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node_ptr(__node_ptr __n)
1905  {
1906  typedef typename __node_alloc_traits::pointer _Ptr;
1907  auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__n);
1908  __n->~__node_type();
1909  __node_alloc_traits::deallocate(_M_node_allocator(), __ptr, 1);
1910  }
1911 
1912  template<typename _NodeAlloc>
1913  void
1914  _Hashtable_alloc<_NodeAlloc>::_M_deallocate_nodes(__node_ptr __n)
1915  {
1916  while (__n)
1917  {
1918  __node_ptr __tmp = __n;
1919  __n = __n->_M_next();
1920  _M_deallocate_node(__tmp);
1921  }
1922  }
1923 
1924  template<typename _NodeAlloc>
1925  auto
1926  _Hashtable_alloc<_NodeAlloc>::_M_allocate_buckets(std::size_t __bkt_count)
1927  -> __buckets_ptr
1928  {
1929  __buckets_alloc_type __alloc(_M_node_allocator());
1930 
1931  auto __ptr = __buckets_alloc_traits::allocate(__alloc, __bkt_count);
1932  __buckets_ptr __p = std::__to_address(__ptr);
1933  __builtin_memset(__p, 0, __bkt_count * sizeof(__node_base_ptr));
1934  return __p;
1935  }
1936 
1937  template<typename _NodeAlloc>
1938  void
1939  _Hashtable_alloc<_NodeAlloc>::
1940  _M_deallocate_buckets(__buckets_ptr __bkts,
1941  std::size_t __bkt_count)
1942  {
1943  typedef typename __buckets_alloc_traits::pointer _Ptr;
1944  auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__bkts);
1945  __buckets_alloc_type __alloc(_M_node_allocator());
1946  __buckets_alloc_traits::deallocate(__alloc, __ptr, __bkt_count);
1947  }
1948 
1949  ///@} hashtable-detail
1950 } // namespace __detail
1951 /// @endcond
1952 _GLIBCXX_END_NAMESPACE_VERSION
1953 } // namespace std
1954 
1955 #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:83
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:86
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:1631
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:428
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)
tuple_element
Definition: array:442
Primary class template, tuple.
Definition: tuple:610
Define a member typedef type to one of two argument types.
Definition: type_traits:2221
is_empty
Definition: type_traits:757
is_constructible
Definition: type_traits:954
Define a member typedef type only if a boolean constant is true.
Definition: type_traits:2194
Uniform interface to all allocator types.
Traits class for iterators.
Uniform interface to all pointer-like types.
Definition: ptr_traits.h:101
Marking input iterators.
Forward iterators support a superset of input iterator operations.
Struct holding two objects of arbitrary type.
Definition: stl_pair.h:213
Uniform interface to C++98 and C++11 allocators.