xref: /netbsd-src/external/gpl3/gcc.old/dist/libstdc++-v3/include/bits/hashtable_policy.h (revision bdc22b2e01993381dcefeff2bc9b56ca75a4235c)
1 // Internal policy header for unordered_set and unordered_map -*- C++ -*-
2 
3 // Copyright (C) 2010-2015 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library.  This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 namespace std _GLIBCXX_VISIBILITY(default)
35 {
36 _GLIBCXX_BEGIN_NAMESPACE_VERSION
37 
38   template<typename _Key, typename _Value, typename _Alloc,
39 	   typename _ExtractKey, typename _Equal,
40 	   typename _H1, typename _H2, typename _Hash,
41 	   typename _RehashPolicy, typename _Traits>
42     class _Hashtable;
43 
44 _GLIBCXX_END_NAMESPACE_VERSION
45 
46 namespace __detail
47 {
48 _GLIBCXX_BEGIN_NAMESPACE_VERSION
49 
50   /**
51    *  @defgroup hashtable-detail Base and Implementation Classes
52    *  @ingroup unordered_associative_containers
53    *  @{
54    */
55   template<typename _Key, typename _Value,
56 	   typename _ExtractKey, typename _Equal,
57 	   typename _H1, typename _H2, typename _Hash, typename _Traits>
58     struct _Hashtable_base;
59 
60   // Helper function: return distance(first, last) for forward
61   // iterators, or 0 for input iterators.
62   template<class _Iterator>
63     inline typename std::iterator_traits<_Iterator>::difference_type
64     __distance_fw(_Iterator __first, _Iterator __last,
65 		  std::input_iterator_tag)
66     { return 0; }
67 
68   template<class _Iterator>
69     inline typename std::iterator_traits<_Iterator>::difference_type
70     __distance_fw(_Iterator __first, _Iterator __last,
71 		  std::forward_iterator_tag)
72     { return std::distance(__first, __last); }
73 
74   template<class _Iterator>
75     inline typename std::iterator_traits<_Iterator>::difference_type
76     __distance_fw(_Iterator __first, _Iterator __last)
77     {
78       typedef typename std::iterator_traits<_Iterator>::iterator_category _Tag;
79       return __distance_fw(__first, __last, _Tag());
80     }
81 
82   // Helper type used to detect whether the hash functor is noexcept.
83   template <typename _Key, typename _Hash>
84     struct __is_noexcept_hash : std::__bool_constant<
85 	noexcept(declval<const _Hash&>()(declval<const _Key&>()))>
86     { };
87 
88   struct _Identity
89   {
90     template<typename _Tp>
91       _Tp&&
92       operator()(_Tp&& __x) const
93       { return std::forward<_Tp>(__x); }
94   };
95 
96   struct _Select1st
97   {
98     template<typename _Tp>
99       auto
100       operator()(_Tp&& __x) const
101       -> decltype(std::get<0>(std::forward<_Tp>(__x)))
102       { return std::get<0>(std::forward<_Tp>(__x)); }
103   };
104 
105   template<typename _NodeAlloc>
106     struct _Hashtable_alloc;
107 
108   // Functor recycling a pool of nodes and using allocation once the pool is
109   // empty.
110   template<typename _NodeAlloc>
111     struct _ReuseOrAllocNode
112     {
113     private:
114       using __node_alloc_type = _NodeAlloc;
115       using __hashtable_alloc = _Hashtable_alloc<__node_alloc_type>;
116       using __value_alloc_type = typename __hashtable_alloc::__value_alloc_type;
117       using __value_alloc_traits =
118 	typename __hashtable_alloc::__value_alloc_traits;
119       using __node_alloc_traits =
120 	typename __hashtable_alloc::__node_alloc_traits;
121       using __node_type = typename __hashtable_alloc::__node_type;
122 
123     public:
124       _ReuseOrAllocNode(__node_type* __nodes, __hashtable_alloc& __h)
125 	: _M_nodes(__nodes), _M_h(__h) { }
126       _ReuseOrAllocNode(const _ReuseOrAllocNode&) = delete;
127 
128       ~_ReuseOrAllocNode()
129       { _M_h._M_deallocate_nodes(_M_nodes); }
130 
131       template<typename _Arg>
132 	__node_type*
133 	operator()(_Arg&& __arg) const
134 	{
135 	  if (_M_nodes)
136 	    {
137 	      __node_type* __node = _M_nodes;
138 	      _M_nodes = _M_nodes->_M_next();
139 	      __node->_M_nxt = nullptr;
140 	      __value_alloc_type __a(_M_h._M_node_allocator());
141 	      __value_alloc_traits::destroy(__a, __node->_M_valptr());
142 	      __try
143 		{
144 		  __value_alloc_traits::construct(__a, __node->_M_valptr(),
145 						  std::forward<_Arg>(__arg));
146 		}
147 	      __catch(...)
148 		{
149 		  __node->~__node_type();
150 		  __node_alloc_traits::deallocate(_M_h._M_node_allocator(),
151 						  __node, 1);
152 		  __throw_exception_again;
153 		}
154 	      return __node;
155 	    }
156 	  return _M_h._M_allocate_node(std::forward<_Arg>(__arg));
157 	}
158 
159     private:
160       mutable __node_type* _M_nodes;
161       __hashtable_alloc& _M_h;
162     };
163 
164   // Functor similar to the previous one but without any pool of nodes to
165   // recycle.
166   template<typename _NodeAlloc>
167     struct _AllocNode
168     {
169     private:
170       using __hashtable_alloc = _Hashtable_alloc<_NodeAlloc>;
171       using __node_type = typename __hashtable_alloc::__node_type;
172 
173     public:
174       _AllocNode(__hashtable_alloc& __h)
175 	: _M_h(__h) { }
176 
177       template<typename _Arg>
178 	__node_type*
179 	operator()(_Arg&& __arg) const
180 	{ return _M_h._M_allocate_node(std::forward<_Arg>(__arg)); }
181 
182     private:
183       __hashtable_alloc& _M_h;
184     };
185 
186   // Auxiliary types used for all instantiations of _Hashtable nodes
187   // and iterators.
188 
189   /**
190    *  struct _Hashtable_traits
191    *
192    *  Important traits for hash tables.
193    *
194    *  @tparam _Cache_hash_code  Boolean value. True if the value of
195    *  the hash function is stored along with the value. This is a
196    *  time-space tradeoff.  Storing it may improve lookup speed by
197    *  reducing the number of times we need to call the _Equal
198    *  function.
199    *
200    *  @tparam _Constant_iterators  Boolean value. True if iterator and
201    *  const_iterator are both constant iterator types. This is true
202    *  for unordered_set and unordered_multiset, false for
203    *  unordered_map and unordered_multimap.
204    *
205    *  @tparam _Unique_keys  Boolean value. True if the return value
206    *  of _Hashtable::count(k) is always at most one, false if it may
207    *  be an arbitrary number. This is true for unordered_set and
208    *  unordered_map, false for unordered_multiset and
209    *  unordered_multimap.
210    */
211   template<bool _Cache_hash_code, bool _Constant_iterators, bool _Unique_keys>
212     struct _Hashtable_traits
213     {
214       using __hash_cached = __bool_constant<_Cache_hash_code>;
215       using __constant_iterators = __bool_constant<_Constant_iterators>;
216       using __unique_keys = __bool_constant<_Unique_keys>;
217     };
218 
219   /**
220    *  struct _Hash_node_base
221    *
222    *  Nodes, used to wrap elements stored in the hash table.  A policy
223    *  template parameter of class template _Hashtable controls whether
224    *  nodes also store a hash code. In some cases (e.g. strings) this
225    *  may be a performance win.
226    */
227   struct _Hash_node_base
228   {
229     _Hash_node_base* _M_nxt;
230 
231     _Hash_node_base() noexcept : _M_nxt() { }
232 
233     _Hash_node_base(_Hash_node_base* __next) noexcept : _M_nxt(__next) { }
234   };
235 
236   /**
237    *  struct _Hash_node_value_base
238    *
239    *  Node type with the value to store.
240    */
241   template<typename _Value>
242     struct _Hash_node_value_base : _Hash_node_base
243     {
244       typedef _Value value_type;
245 
246       __gnu_cxx::__aligned_buffer<_Value> _M_storage;
247 
248       _Value*
249       _M_valptr() noexcept
250       { return _M_storage._M_ptr(); }
251 
252       const _Value*
253       _M_valptr() const noexcept
254       { return _M_storage._M_ptr(); }
255 
256       _Value&
257       _M_v() noexcept
258       { return *_M_valptr(); }
259 
260       const _Value&
261       _M_v() const noexcept
262       { return *_M_valptr(); }
263     };
264 
265   /**
266    *  Primary template struct _Hash_node.
267    */
268   template<typename _Value, bool _Cache_hash_code>
269     struct _Hash_node;
270 
271   /**
272    *  Specialization for nodes with caches, struct _Hash_node.
273    *
274    *  Base class is __detail::_Hash_node_value_base.
275    */
276   template<typename _Value>
277     struct _Hash_node<_Value, true> : _Hash_node_value_base<_Value>
278     {
279       std::size_t  _M_hash_code;
280 
281       _Hash_node*
282       _M_next() const noexcept
283       { return static_cast<_Hash_node*>(this->_M_nxt); }
284     };
285 
286   /**
287    *  Specialization for nodes without caches, struct _Hash_node.
288    *
289    *  Base class is __detail::_Hash_node_value_base.
290    */
291   template<typename _Value>
292     struct _Hash_node<_Value, false> : _Hash_node_value_base<_Value>
293     {
294       _Hash_node*
295       _M_next() const noexcept
296       { return static_cast<_Hash_node*>(this->_M_nxt); }
297     };
298 
299   /// Base class for node iterators.
300   template<typename _Value, bool _Cache_hash_code>
301     struct _Node_iterator_base
302     {
303       using __node_type = _Hash_node<_Value, _Cache_hash_code>;
304 
305       __node_type*  _M_cur;
306 
307       _Node_iterator_base(__node_type* __p) noexcept
308       : _M_cur(__p) { }
309 
310       void
311       _M_incr() noexcept
312       { _M_cur = _M_cur->_M_next(); }
313     };
314 
315   template<typename _Value, bool _Cache_hash_code>
316     inline bool
317     operator==(const _Node_iterator_base<_Value, _Cache_hash_code>& __x,
318 	       const _Node_iterator_base<_Value, _Cache_hash_code >& __y)
319     noexcept
320     { return __x._M_cur == __y._M_cur; }
321 
322   template<typename _Value, bool _Cache_hash_code>
323     inline bool
324     operator!=(const _Node_iterator_base<_Value, _Cache_hash_code>& __x,
325 	       const _Node_iterator_base<_Value, _Cache_hash_code>& __y)
326     noexcept
327     { return __x._M_cur != __y._M_cur; }
328 
329   /// Node iterators, used to iterate through all the hashtable.
330   template<typename _Value, bool __constant_iterators, bool __cache>
331     struct _Node_iterator
332     : public _Node_iterator_base<_Value, __cache>
333     {
334     private:
335       using __base_type = _Node_iterator_base<_Value, __cache>;
336       using __node_type = typename __base_type::__node_type;
337 
338     public:
339       typedef _Value					value_type;
340       typedef std::ptrdiff_t				difference_type;
341       typedef std::forward_iterator_tag			iterator_category;
342 
343       using pointer = typename std::conditional<__constant_iterators,
344 						const _Value*, _Value*>::type;
345 
346       using reference = typename std::conditional<__constant_iterators,
347 						  const _Value&, _Value&>::type;
348 
349       _Node_iterator() noexcept
350       : __base_type(0) { }
351 
352       explicit
353       _Node_iterator(__node_type* __p) noexcept
354       : __base_type(__p) { }
355 
356       reference
357       operator*() const noexcept
358       { return this->_M_cur->_M_v(); }
359 
360       pointer
361       operator->() const noexcept
362       { return this->_M_cur->_M_valptr(); }
363 
364       _Node_iterator&
365       operator++() noexcept
366       {
367 	this->_M_incr();
368 	return *this;
369       }
370 
371       _Node_iterator
372       operator++(int) noexcept
373       {
374 	_Node_iterator __tmp(*this);
375 	this->_M_incr();
376 	return __tmp;
377       }
378     };
379 
380   /// Node const_iterators, used to iterate through all the hashtable.
381   template<typename _Value, bool __constant_iterators, bool __cache>
382     struct _Node_const_iterator
383     : public _Node_iterator_base<_Value, __cache>
384     {
385     private:
386       using __base_type = _Node_iterator_base<_Value, __cache>;
387       using __node_type = typename __base_type::__node_type;
388 
389     public:
390       typedef _Value					value_type;
391       typedef std::ptrdiff_t				difference_type;
392       typedef std::forward_iterator_tag			iterator_category;
393 
394       typedef const _Value*				pointer;
395       typedef const _Value&				reference;
396 
397       _Node_const_iterator() noexcept
398       : __base_type(0) { }
399 
400       explicit
401       _Node_const_iterator(__node_type* __p) noexcept
402       : __base_type(__p) { }
403 
404       _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators,
405 			   __cache>& __x) noexcept
406       : __base_type(__x._M_cur) { }
407 
408       reference
409       operator*() const noexcept
410       { return this->_M_cur->_M_v(); }
411 
412       pointer
413       operator->() const noexcept
414       { return this->_M_cur->_M_valptr(); }
415 
416       _Node_const_iterator&
417       operator++() noexcept
418       {
419 	this->_M_incr();
420 	return *this;
421       }
422 
423       _Node_const_iterator
424       operator++(int) noexcept
425       {
426 	_Node_const_iterator __tmp(*this);
427 	this->_M_incr();
428 	return __tmp;
429       }
430     };
431 
432   // Many of class template _Hashtable's template parameters are policy
433   // classes.  These are defaults for the policies.
434 
435   /// Default range hashing function: use division to fold a large number
436   /// into the range [0, N).
437   struct _Mod_range_hashing
438   {
439     typedef std::size_t first_argument_type;
440     typedef std::size_t second_argument_type;
441     typedef std::size_t result_type;
442 
443     result_type
444     operator()(first_argument_type __num,
445 	       second_argument_type __den) const noexcept
446     { return __num % __den; }
447   };
448 
449   /// Default ranged hash function H.  In principle it should be a
450   /// function object composed from objects of type H1 and H2 such that
451   /// h(k, N) = h2(h1(k), N), but that would mean making extra copies of
452   /// h1 and h2.  So instead we'll just use a tag to tell class template
453   /// hashtable to do that composition.
454   struct _Default_ranged_hash { };
455 
456   /// Default value for rehash policy.  Bucket size is (usually) the
457   /// smallest prime that keeps the load factor small enough.
458   struct _Prime_rehash_policy
459   {
460     _Prime_rehash_policy(float __z = 1.0) noexcept
461     : _M_max_load_factor(__z), _M_next_resize(0) { }
462 
463     float
464     max_load_factor() const noexcept
465     { return _M_max_load_factor; }
466 
467     // Return a bucket size no smaller than n.
468     std::size_t
469     _M_next_bkt(std::size_t __n) const;
470 
471     // Return a bucket count appropriate for n elements
472     std::size_t
473     _M_bkt_for_elements(std::size_t __n) const
474     { return __builtin_ceil(__n / (long double)_M_max_load_factor); }
475 
476     // __n_bkt is current bucket count, __n_elt is current element count,
477     // and __n_ins is number of elements to be inserted.  Do we need to
478     // increase bucket count?  If so, return make_pair(true, n), where n
479     // is the new bucket count.  If not, return make_pair(false, 0).
480     std::pair<bool, std::size_t>
481     _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
482 		   std::size_t __n_ins) const;
483 
484     typedef std::size_t _State;
485 
486     _State
487     _M_state() const
488     { return _M_next_resize; }
489 
490     void
491     _M_reset() noexcept
492     { _M_next_resize = 0; }
493 
494     void
495     _M_reset(_State __state)
496     { _M_next_resize = __state; }
497 
498     enum { _S_n_primes = sizeof(unsigned long) != 8 ? 256 : 256 + 48 };
499 
500     static const std::size_t _S_growth_factor = 2;
501 
502     float		_M_max_load_factor;
503     mutable std::size_t	_M_next_resize;
504   };
505 
506   // Base classes for std::_Hashtable.  We define these base classes
507   // because in some cases we want to do different things depending on
508   // the value of a policy class.  In some cases the policy class
509   // affects which member functions and nested typedefs are defined;
510   // we handle that by specializing base class templates.  Several of
511   // the base class templates need to access other members of class
512   // template _Hashtable, so we use a variant of the "Curiously
513   // Recurring Template Pattern" (CRTP) technique.
514 
515   /**
516    *  Primary class template _Map_base.
517    *
518    *  If the hashtable has a value type of the form pair<T1, T2> and a
519    *  key extraction policy (_ExtractKey) that returns the first part
520    *  of the pair, the hashtable gets a mapped_type typedef.  If it
521    *  satisfies those criteria and also has unique keys, then it also
522    *  gets an operator[].
523    */
524   template<typename _Key, typename _Value, typename _Alloc,
525 	   typename _ExtractKey, typename _Equal,
526 	   typename _H1, typename _H2, typename _Hash,
527 	   typename _RehashPolicy, typename _Traits,
528 	   bool _Unique_keys = _Traits::__unique_keys::value>
529     struct _Map_base { };
530 
531   /// Partial specialization, __unique_keys set to false.
532   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
533 	   typename _H1, typename _H2, typename _Hash,
534 	   typename _RehashPolicy, typename _Traits>
535     struct _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
536 		     _H1, _H2, _Hash, _RehashPolicy, _Traits, false>
537     {
538       using mapped_type = typename std::tuple_element<1, _Pair>::type;
539     };
540 
541   /// Partial specialization, __unique_keys set to true.
542   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
543 	   typename _H1, typename _H2, typename _Hash,
544 	   typename _RehashPolicy, typename _Traits>
545     struct _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
546 		     _H1, _H2, _Hash, _RehashPolicy, _Traits, true>
547     {
548     private:
549       using __hashtable_base = __detail::_Hashtable_base<_Key, _Pair,
550 							 _Select1st,
551 							_Equal, _H1, _H2, _Hash,
552 							  _Traits>;
553 
554       using __hashtable = _Hashtable<_Key, _Pair, _Alloc,
555 				     _Select1st, _Equal,
556 				     _H1, _H2, _Hash, _RehashPolicy, _Traits>;
557 
558       using __hash_code = typename __hashtable_base::__hash_code;
559       using __node_type = typename __hashtable_base::__node_type;
560 
561     public:
562       using key_type = typename __hashtable_base::key_type;
563       using iterator = typename __hashtable_base::iterator;
564       using mapped_type = typename std::tuple_element<1, _Pair>::type;
565 
566       mapped_type&
567       operator[](const key_type& __k);
568 
569       mapped_type&
570       operator[](key_type&& __k);
571 
572       // _GLIBCXX_RESOLVE_LIB_DEFECTS
573       // DR 761. unordered_map needs an at() member function.
574       mapped_type&
575       at(const key_type& __k);
576 
577       const mapped_type&
578       at(const key_type& __k) const;
579     };
580 
581   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
582 	   typename _H1, typename _H2, typename _Hash,
583 	   typename _RehashPolicy, typename _Traits>
584     auto
585     _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
586 	      _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
587     operator[](const key_type& __k)
588     -> mapped_type&
589     {
590       __hashtable* __h = static_cast<__hashtable*>(this);
591       __hash_code __code = __h->_M_hash_code(__k);
592       std::size_t __n = __h->_M_bucket_index(__k, __code);
593       __node_type* __p = __h->_M_find_node(__n, __k, __code);
594 
595       if (!__p)
596 	{
597 	  __p = __h->_M_allocate_node(std::piecewise_construct,
598 				      std::tuple<const key_type&>(__k),
599 				      std::tuple<>());
600 	  return __h->_M_insert_unique_node(__n, __code, __p)->second;
601 	}
602 
603       return __p->_M_v().second;
604     }
605 
606   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
607 	   typename _H1, typename _H2, typename _Hash,
608 	   typename _RehashPolicy, typename _Traits>
609     auto
610     _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
611 	      _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
612     operator[](key_type&& __k)
613     -> mapped_type&
614     {
615       __hashtable* __h = static_cast<__hashtable*>(this);
616       __hash_code __code = __h->_M_hash_code(__k);
617       std::size_t __n = __h->_M_bucket_index(__k, __code);
618       __node_type* __p = __h->_M_find_node(__n, __k, __code);
619 
620       if (!__p)
621 	{
622 	  __p = __h->_M_allocate_node(std::piecewise_construct,
623 				      std::forward_as_tuple(std::move(__k)),
624 				      std::tuple<>());
625 	  return __h->_M_insert_unique_node(__n, __code, __p)->second;
626 	}
627 
628       return __p->_M_v().second;
629     }
630 
631   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
632 	   typename _H1, typename _H2, typename _Hash,
633 	   typename _RehashPolicy, typename _Traits>
634     auto
635     _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
636 	      _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
637     at(const key_type& __k)
638     -> mapped_type&
639     {
640       __hashtable* __h = static_cast<__hashtable*>(this);
641       __hash_code __code = __h->_M_hash_code(__k);
642       std::size_t __n = __h->_M_bucket_index(__k, __code);
643       __node_type* __p = __h->_M_find_node(__n, __k, __code);
644 
645       if (!__p)
646 	__throw_out_of_range(__N("_Map_base::at"));
647       return __p->_M_v().second;
648     }
649 
650   template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
651 	   typename _H1, typename _H2, typename _Hash,
652 	   typename _RehashPolicy, typename _Traits>
653     auto
654     _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
655 	      _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
656     at(const key_type& __k) const
657     -> const mapped_type&
658     {
659       const __hashtable* __h = static_cast<const __hashtable*>(this);
660       __hash_code __code = __h->_M_hash_code(__k);
661       std::size_t __n = __h->_M_bucket_index(__k, __code);
662       __node_type* __p = __h->_M_find_node(__n, __k, __code);
663 
664       if (!__p)
665 	__throw_out_of_range(__N("_Map_base::at"));
666       return __p->_M_v().second;
667     }
668 
669   /**
670    *  Primary class template _Insert_base.
671    *
672    *  insert member functions appropriate to all _Hashtables.
673    */
674   template<typename _Key, typename _Value, typename _Alloc,
675 	   typename _ExtractKey, typename _Equal,
676 	   typename _H1, typename _H2, typename _Hash,
677 	   typename _RehashPolicy, typename _Traits>
678     struct _Insert_base
679     {
680     protected:
681       using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
682 				     _Equal, _H1, _H2, _Hash,
683 				     _RehashPolicy, _Traits>;
684 
685       using __hashtable_base = _Hashtable_base<_Key, _Value, _ExtractKey,
686 					       _Equal, _H1, _H2, _Hash,
687 					       _Traits>;
688 
689       using value_type = typename __hashtable_base::value_type;
690       using iterator = typename __hashtable_base::iterator;
691       using const_iterator =  typename __hashtable_base::const_iterator;
692       using size_type = typename __hashtable_base::size_type;
693 
694       using __unique_keys = typename __hashtable_base::__unique_keys;
695       using __ireturn_type = typename __hashtable_base::__ireturn_type;
696       using __node_type = _Hash_node<_Value, _Traits::__hash_cached::value>;
697       using __node_alloc_type = __alloc_rebind<_Alloc, __node_type>;
698       using __node_gen_type = _AllocNode<__node_alloc_type>;
699 
700       __hashtable&
701       _M_conjure_hashtable()
702       { return *(static_cast<__hashtable*>(this)); }
703 
704       template<typename _InputIterator, typename _NodeGetter>
705 	void
706 	_M_insert_range(_InputIterator __first, _InputIterator __last,
707 			const _NodeGetter&);
708 
709     public:
710       __ireturn_type
711       insert(const value_type& __v)
712       {
713 	__hashtable& __h = _M_conjure_hashtable();
714 	__node_gen_type __node_gen(__h);
715 	return __h._M_insert(__v, __node_gen, __unique_keys());
716       }
717 
718       iterator
719       insert(const_iterator __hint, const value_type& __v)
720       {
721 	__hashtable& __h = _M_conjure_hashtable();
722 	__node_gen_type __node_gen(__h);
723 	return __h._M_insert(__hint, __v, __node_gen, __unique_keys());
724       }
725 
726       void
727       insert(initializer_list<value_type> __l)
728       { this->insert(__l.begin(), __l.end()); }
729 
730       template<typename _InputIterator>
731 	void
732 	insert(_InputIterator __first, _InputIterator __last)
733 	{
734 	  __hashtable& __h = _M_conjure_hashtable();
735 	  __node_gen_type __node_gen(__h);
736 	  return _M_insert_range(__first, __last, __node_gen);
737 	}
738     };
739 
740   template<typename _Key, typename _Value, typename _Alloc,
741 	   typename _ExtractKey, typename _Equal,
742 	   typename _H1, typename _H2, typename _Hash,
743 	   typename _RehashPolicy, typename _Traits>
744     template<typename _InputIterator, typename _NodeGetter>
745       void
746       _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
747 		    _RehashPolicy, _Traits>::
748       _M_insert_range(_InputIterator __first, _InputIterator __last,
749 		      const _NodeGetter& __node_gen)
750       {
751 	using __rehash_type = typename __hashtable::__rehash_type;
752 	using __rehash_state = typename __hashtable::__rehash_state;
753 	using pair_type = std::pair<bool, std::size_t>;
754 
755 	size_type __n_elt = __detail::__distance_fw(__first, __last);
756 
757 	__hashtable& __h = _M_conjure_hashtable();
758 	__rehash_type& __rehash = __h._M_rehash_policy;
759 	const __rehash_state& __saved_state = __rehash._M_state();
760 	pair_type __do_rehash = __rehash._M_need_rehash(__h._M_bucket_count,
761 							__h._M_element_count,
762 							__n_elt);
763 
764 	if (__do_rehash.first)
765 	  __h._M_rehash(__do_rehash.second, __saved_state);
766 
767 	for (; __first != __last; ++__first)
768 	  __h._M_insert(*__first, __node_gen, __unique_keys());
769       }
770 
771   /**
772    *  Primary class template _Insert.
773    *
774    *  Select insert member functions appropriate to _Hashtable policy choices.
775    */
776   template<typename _Key, typename _Value, typename _Alloc,
777 	   typename _ExtractKey, typename _Equal,
778 	   typename _H1, typename _H2, typename _Hash,
779 	   typename _RehashPolicy, typename _Traits,
780 	   bool _Constant_iterators = _Traits::__constant_iterators::value,
781 	   bool _Unique_keys = _Traits::__unique_keys::value>
782     struct _Insert;
783 
784   /// Specialization.
785   template<typename _Key, typename _Value, typename _Alloc,
786 	   typename _ExtractKey, typename _Equal,
787 	   typename _H1, typename _H2, typename _Hash,
788 	   typename _RehashPolicy, typename _Traits>
789     struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
790 		   _RehashPolicy, _Traits, true, true>
791     : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
792 			   _H1, _H2, _Hash, _RehashPolicy, _Traits>
793     {
794       using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
795 					_Equal, _H1, _H2, _Hash,
796 					_RehashPolicy, _Traits>;
797       using value_type = typename __base_type::value_type;
798       using iterator = typename __base_type::iterator;
799       using const_iterator =  typename __base_type::const_iterator;
800 
801       using __unique_keys = typename __base_type::__unique_keys;
802       using __hashtable = typename __base_type::__hashtable;
803       using __node_gen_type = typename __base_type::__node_gen_type;
804 
805       using __base_type::insert;
806 
807       std::pair<iterator, bool>
808       insert(value_type&& __v)
809       {
810 	__hashtable& __h = this->_M_conjure_hashtable();
811 	__node_gen_type __node_gen(__h);
812 	return __h._M_insert(std::move(__v), __node_gen, __unique_keys());
813       }
814 
815       iterator
816       insert(const_iterator __hint, value_type&& __v)
817       {
818 	__hashtable& __h = this->_M_conjure_hashtable();
819 	__node_gen_type __node_gen(__h);
820 	return __h._M_insert(__hint, std::move(__v), __node_gen,
821 			     __unique_keys());
822       }
823     };
824 
825   /// Specialization.
826   template<typename _Key, typename _Value, typename _Alloc,
827 	   typename _ExtractKey, typename _Equal,
828 	   typename _H1, typename _H2, typename _Hash,
829 	   typename _RehashPolicy, typename _Traits>
830     struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
831 		   _RehashPolicy, _Traits, true, false>
832     : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
833 			   _H1, _H2, _Hash, _RehashPolicy, _Traits>
834     {
835       using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
836 					_Equal, _H1, _H2, _Hash,
837 					_RehashPolicy, _Traits>;
838       using value_type = typename __base_type::value_type;
839       using iterator = typename __base_type::iterator;
840       using const_iterator =  typename __base_type::const_iterator;
841 
842       using __unique_keys = typename __base_type::__unique_keys;
843       using __hashtable = typename __base_type::__hashtable;
844       using __node_gen_type = typename __base_type::__node_gen_type;
845 
846       using __base_type::insert;
847 
848       iterator
849       insert(value_type&& __v)
850       {
851 	__hashtable& __h = this->_M_conjure_hashtable();
852 	__node_gen_type __node_gen(__h);
853 	return __h._M_insert(std::move(__v), __node_gen, __unique_keys());
854       }
855 
856       iterator
857       insert(const_iterator __hint, value_type&& __v)
858       {
859 	__hashtable& __h = this->_M_conjure_hashtable();
860 	__node_gen_type __node_gen(__h);
861 	return __h._M_insert(__hint, std::move(__v), __node_gen,
862 			     __unique_keys());
863       }
864     };
865 
866   /// Specialization.
867   template<typename _Key, typename _Value, typename _Alloc,
868 	   typename _ExtractKey, typename _Equal,
869 	   typename _H1, typename _H2, typename _Hash,
870 	   typename _RehashPolicy, typename _Traits, bool _Unique_keys>
871     struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
872 		   _RehashPolicy, _Traits, false, _Unique_keys>
873     : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
874 			   _H1, _H2, _Hash, _RehashPolicy, _Traits>
875     {
876       using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
877 				       _Equal, _H1, _H2, _Hash,
878 				       _RehashPolicy, _Traits>;
879       using value_type = typename __base_type::value_type;
880       using iterator = typename __base_type::iterator;
881       using const_iterator =  typename __base_type::const_iterator;
882 
883       using __unique_keys = typename __base_type::__unique_keys;
884       using __hashtable = typename __base_type::__hashtable;
885       using __ireturn_type = typename __base_type::__ireturn_type;
886 
887       using __base_type::insert;
888 
889       template<typename _Pair>
890 	using __is_cons = std::is_constructible<value_type, _Pair&&>;
891 
892       template<typename _Pair>
893 	using _IFcons = std::enable_if<__is_cons<_Pair>::value>;
894 
895       template<typename _Pair>
896 	using _IFconsp = typename _IFcons<_Pair>::type;
897 
898       template<typename _Pair, typename = _IFconsp<_Pair>>
899 	__ireturn_type
900 	insert(_Pair&& __v)
901 	{
902 	  __hashtable& __h = this->_M_conjure_hashtable();
903 	  return __h._M_emplace(__unique_keys(), std::forward<_Pair>(__v));
904 	}
905 
906       template<typename _Pair, typename = _IFconsp<_Pair>>
907 	iterator
908 	insert(const_iterator __hint, _Pair&& __v)
909 	{
910 	  __hashtable& __h = this->_M_conjure_hashtable();
911 	  return __h._M_emplace(__hint, __unique_keys(),
912 				std::forward<_Pair>(__v));
913 	}
914    };
915 
916   /**
917    *  Primary class template  _Rehash_base.
918    *
919    *  Give hashtable the max_load_factor functions and reserve iff the
920    *  rehash policy is _Prime_rehash_policy.
921   */
922   template<typename _Key, typename _Value, typename _Alloc,
923 	   typename _ExtractKey, typename _Equal,
924 	   typename _H1, typename _H2, typename _Hash,
925 	   typename _RehashPolicy, typename _Traits>
926     struct _Rehash_base;
927 
928   /// Specialization.
929   template<typename _Key, typename _Value, typename _Alloc,
930 	   typename _ExtractKey, typename _Equal,
931 	   typename _H1, typename _H2, typename _Hash, typename _Traits>
932     struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
933 			_H1, _H2, _Hash, _Prime_rehash_policy, _Traits>
934     {
935       using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
936 				     _Equal, _H1, _H2, _Hash,
937 				     _Prime_rehash_policy, _Traits>;
938 
939       float
940       max_load_factor() const noexcept
941       {
942 	const __hashtable* __this = static_cast<const __hashtable*>(this);
943 	return __this->__rehash_policy().max_load_factor();
944       }
945 
946       void
947       max_load_factor(float __z)
948       {
949 	__hashtable* __this = static_cast<__hashtable*>(this);
950 	__this->__rehash_policy(_Prime_rehash_policy(__z));
951       }
952 
953       void
954       reserve(std::size_t __n)
955       {
956 	__hashtable* __this = static_cast<__hashtable*>(this);
957 	__this->rehash(__builtin_ceil(__n / max_load_factor()));
958       }
959     };
960 
961   /**
962    *  Primary class template _Hashtable_ebo_helper.
963    *
964    *  Helper class using EBO when it is not forbidden (the type is not
965    *  final) and when it is worth it (the type is empty.)
966    */
967   template<int _Nm, typename _Tp,
968 	   bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
969     struct _Hashtable_ebo_helper;
970 
971   /// Specialization using EBO.
972   template<int _Nm, typename _Tp>
973     struct _Hashtable_ebo_helper<_Nm, _Tp, true>
974     : private _Tp
975     {
976       _Hashtable_ebo_helper() = default;
977 
978       template<typename _OtherTp>
979 	_Hashtable_ebo_helper(_OtherTp&& __tp)
980 	  : _Tp(std::forward<_OtherTp>(__tp))
981 	{ }
982 
983       static const _Tp&
984       _S_cget(const _Hashtable_ebo_helper& __eboh)
985       { return static_cast<const _Tp&>(__eboh); }
986 
987       static _Tp&
988       _S_get(_Hashtable_ebo_helper& __eboh)
989       { return static_cast<_Tp&>(__eboh); }
990     };
991 
992   /// Specialization not using EBO.
993   template<int _Nm, typename _Tp>
994     struct _Hashtable_ebo_helper<_Nm, _Tp, false>
995     {
996       _Hashtable_ebo_helper() = default;
997 
998       template<typename _OtherTp>
999 	_Hashtable_ebo_helper(_OtherTp&& __tp)
1000 	  : _M_tp(std::forward<_OtherTp>(__tp))
1001 	{ }
1002 
1003       static const _Tp&
1004       _S_cget(const _Hashtable_ebo_helper& __eboh)
1005       { return __eboh._M_tp; }
1006 
1007       static _Tp&
1008       _S_get(_Hashtable_ebo_helper& __eboh)
1009       { return __eboh._M_tp; }
1010 
1011     private:
1012       _Tp _M_tp;
1013     };
1014 
1015   /**
1016    *  Primary class template _Local_iterator_base.
1017    *
1018    *  Base class for local iterators, used to iterate within a bucket
1019    *  but not between buckets.
1020    */
1021   template<typename _Key, typename _Value, typename _ExtractKey,
1022 	   typename _H1, typename _H2, typename _Hash,
1023 	   bool __cache_hash_code>
1024     struct _Local_iterator_base;
1025 
1026   /**
1027    *  Primary class template _Hash_code_base.
1028    *
1029    *  Encapsulates two policy issues that aren't quite orthogonal.
1030    *   (1) the difference between using a ranged hash function and using
1031    *       the combination of a hash function and a range-hashing function.
1032    *       In the former case we don't have such things as hash codes, so
1033    *       we have a dummy type as placeholder.
1034    *   (2) Whether or not we cache hash codes.  Caching hash codes is
1035    *       meaningless if we have a ranged hash function.
1036    *
1037    *  We also put the key extraction objects here, for convenience.
1038    *  Each specialization derives from one or more of the template
1039    *  parameters to benefit from Ebo. This is important as this type
1040    *  is inherited in some cases by the _Local_iterator_base type used
1041    *  to implement local_iterator and const_local_iterator. As with
1042    *  any iterator type we prefer to make it as small as possible.
1043    *
1044    *  Primary template is unused except as a hook for specializations.
1045    */
1046   template<typename _Key, typename _Value, typename _ExtractKey,
1047 	   typename _H1, typename _H2, typename _Hash,
1048 	   bool __cache_hash_code>
1049     struct _Hash_code_base;
1050 
1051   /// Specialization: ranged hash function, no caching hash codes.  H1
1052   /// and H2 are provided but ignored.  We define a dummy hash code type.
1053   template<typename _Key, typename _Value, typename _ExtractKey,
1054 	   typename _H1, typename _H2, typename _Hash>
1055     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash, false>
1056     : private _Hashtable_ebo_helper<0, _ExtractKey>,
1057       private _Hashtable_ebo_helper<1, _Hash>
1058     {
1059     private:
1060       using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;
1061       using __ebo_hash = _Hashtable_ebo_helper<1, _Hash>;
1062 
1063     protected:
1064       typedef void* 					__hash_code;
1065       typedef _Hash_node<_Value, false>			__node_type;
1066 
1067       // We need the default constructor for the local iterators and _Hashtable
1068       // default constructor.
1069       _Hash_code_base() = default;
1070 
1071       _Hash_code_base(const _ExtractKey& __ex, const _H1&, const _H2&,
1072 		      const _Hash& __h)
1073       : __ebo_extract_key(__ex), __ebo_hash(__h) { }
1074 
1075       __hash_code
1076       _M_hash_code(const _Key& __key) const
1077       { return 0; }
1078 
1079       std::size_t
1080       _M_bucket_index(const _Key& __k, __hash_code, std::size_t __n) const
1081       { return _M_ranged_hash()(__k, __n); }
1082 
1083       std::size_t
1084       _M_bucket_index(const __node_type* __p, std::size_t __n) const
1085 	noexcept( noexcept(declval<const _Hash&>()(declval<const _Key&>(),
1086 						   (std::size_t)0)) )
1087       { return _M_ranged_hash()(_M_extract()(__p->_M_v()), __n); }
1088 
1089       void
1090       _M_store_code(__node_type*, __hash_code) const
1091       { }
1092 
1093       void
1094       _M_copy_code(__node_type*, const __node_type*) const
1095       { }
1096 
1097       void
1098       _M_swap(_Hash_code_base& __x)
1099       {
1100 	std::swap(_M_extract(), __x._M_extract());
1101 	std::swap(_M_ranged_hash(), __x._M_ranged_hash());
1102       }
1103 
1104       const _ExtractKey&
1105       _M_extract() const { return __ebo_extract_key::_S_cget(*this); }
1106 
1107       _ExtractKey&
1108       _M_extract() { return __ebo_extract_key::_S_get(*this); }
1109 
1110       const _Hash&
1111       _M_ranged_hash() const { return __ebo_hash::_S_cget(*this); }
1112 
1113       _Hash&
1114       _M_ranged_hash() { return __ebo_hash::_S_get(*this); }
1115     };
1116 
1117   // No specialization for ranged hash function while caching hash codes.
1118   // That combination is meaningless, and trying to do it is an error.
1119 
1120   /// Specialization: ranged hash function, cache hash codes.  This
1121   /// combination is meaningless, so we provide only a declaration
1122   /// and no definition.
1123   template<typename _Key, typename _Value, typename _ExtractKey,
1124 	   typename _H1, typename _H2, typename _Hash>
1125     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash, true>;
1126 
1127   /// Specialization: hash function and range-hashing function, no
1128   /// caching of hash codes.
1129   /// Provides typedef and accessor required by C++ 11.
1130   template<typename _Key, typename _Value, typename _ExtractKey,
1131 	   typename _H1, typename _H2>
1132     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2,
1133 			   _Default_ranged_hash, false>
1134     : private _Hashtable_ebo_helper<0, _ExtractKey>,
1135       private _Hashtable_ebo_helper<1, _H1>,
1136       private _Hashtable_ebo_helper<2, _H2>
1137     {
1138     private:
1139       using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;
1140       using __ebo_h1 = _Hashtable_ebo_helper<1, _H1>;
1141       using __ebo_h2 = _Hashtable_ebo_helper<2, _H2>;
1142 
1143       // Gives the local iterator implementation access to _M_bucket_index().
1144       friend struct _Local_iterator_base<_Key, _Value, _ExtractKey, _H1, _H2,
1145 					 _Default_ranged_hash, false>;
1146 
1147     public:
1148       typedef _H1 					hasher;
1149 
1150       hasher
1151       hash_function() const
1152       { return _M_h1(); }
1153 
1154     protected:
1155       typedef std::size_t 				__hash_code;
1156       typedef _Hash_node<_Value, false>			__node_type;
1157 
1158       // We need the default constructor for the local iterators and _Hashtable
1159       // default constructor.
1160       _Hash_code_base() = default;
1161 
1162       _Hash_code_base(const _ExtractKey& __ex,
1163 		      const _H1& __h1, const _H2& __h2,
1164 		      const _Default_ranged_hash&)
1165       : __ebo_extract_key(__ex), __ebo_h1(__h1), __ebo_h2(__h2) { }
1166 
1167       __hash_code
1168       _M_hash_code(const _Key& __k) const
1169       { return _M_h1()(__k); }
1170 
1171       std::size_t
1172       _M_bucket_index(const _Key&, __hash_code __c, std::size_t __n) const
1173       { return _M_h2()(__c, __n); }
1174 
1175       std::size_t
1176       _M_bucket_index(const __node_type* __p, std::size_t __n) const
1177 	noexcept( noexcept(declval<const _H1&>()(declval<const _Key&>()))
1178 		  && noexcept(declval<const _H2&>()((__hash_code)0,
1179 						    (std::size_t)0)) )
1180       { return _M_h2()(_M_h1()(_M_extract()(__p->_M_v())), __n); }
1181 
1182       void
1183       _M_store_code(__node_type*, __hash_code) const
1184       { }
1185 
1186       void
1187       _M_copy_code(__node_type*, const __node_type*) const
1188       { }
1189 
1190       void
1191       _M_swap(_Hash_code_base& __x)
1192       {
1193 	std::swap(_M_extract(), __x._M_extract());
1194 	std::swap(_M_h1(), __x._M_h1());
1195 	std::swap(_M_h2(), __x._M_h2());
1196       }
1197 
1198       const _ExtractKey&
1199       _M_extract() const { return __ebo_extract_key::_S_cget(*this); }
1200 
1201       _ExtractKey&
1202       _M_extract() { return __ebo_extract_key::_S_get(*this); }
1203 
1204       const _H1&
1205       _M_h1() const { return __ebo_h1::_S_cget(*this); }
1206 
1207       _H1&
1208       _M_h1() { return __ebo_h1::_S_get(*this); }
1209 
1210       const _H2&
1211       _M_h2() const { return __ebo_h2::_S_cget(*this); }
1212 
1213       _H2&
1214       _M_h2() { return __ebo_h2::_S_get(*this); }
1215     };
1216 
1217   /// Specialization: hash function and range-hashing function,
1218   /// caching hash codes.  H is provided but ignored.  Provides
1219   /// typedef and accessor required by C++ 11.
1220   template<typename _Key, typename _Value, typename _ExtractKey,
1221 	   typename _H1, typename _H2>
1222     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2,
1223 			   _Default_ranged_hash, true>
1224     : private _Hashtable_ebo_helper<0, _ExtractKey>,
1225       private _Hashtable_ebo_helper<1, _H1>,
1226       private _Hashtable_ebo_helper<2, _H2>
1227     {
1228     private:
1229       // Gives the local iterator implementation access to _M_h2().
1230       friend struct _Local_iterator_base<_Key, _Value, _ExtractKey, _H1, _H2,
1231 					 _Default_ranged_hash, true>;
1232 
1233       using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;
1234       using __ebo_h1 = _Hashtable_ebo_helper<1, _H1>;
1235       using __ebo_h2 = _Hashtable_ebo_helper<2, _H2>;
1236 
1237     public:
1238       typedef _H1 					hasher;
1239 
1240       hasher
1241       hash_function() const
1242       { return _M_h1(); }
1243 
1244     protected:
1245       typedef std::size_t 				__hash_code;
1246       typedef _Hash_node<_Value, true>			__node_type;
1247 
1248       // We need the default constructor for _Hashtable default constructor.
1249       _Hash_code_base() = default;
1250       _Hash_code_base(const _ExtractKey& __ex,
1251 		      const _H1& __h1, const _H2& __h2,
1252 		      const _Default_ranged_hash&)
1253       : __ebo_extract_key(__ex), __ebo_h1(__h1), __ebo_h2(__h2) { }
1254 
1255       __hash_code
1256       _M_hash_code(const _Key& __k) const
1257       { return _M_h1()(__k); }
1258 
1259       std::size_t
1260       _M_bucket_index(const _Key&, __hash_code __c,
1261 		      std::size_t __n) const
1262       { return _M_h2()(__c, __n); }
1263 
1264       std::size_t
1265       _M_bucket_index(const __node_type* __p, std::size_t __n) const
1266 	noexcept( noexcept(declval<const _H2&>()((__hash_code)0,
1267 						 (std::size_t)0)) )
1268       { return _M_h2()(__p->_M_hash_code, __n); }
1269 
1270       void
1271       _M_store_code(__node_type* __n, __hash_code __c) const
1272       { __n->_M_hash_code = __c; }
1273 
1274       void
1275       _M_copy_code(__node_type* __to, const __node_type* __from) const
1276       { __to->_M_hash_code = __from->_M_hash_code; }
1277 
1278       void
1279       _M_swap(_Hash_code_base& __x)
1280       {
1281 	std::swap(_M_extract(), __x._M_extract());
1282 	std::swap(_M_h1(), __x._M_h1());
1283 	std::swap(_M_h2(), __x._M_h2());
1284       }
1285 
1286       const _ExtractKey&
1287       _M_extract() const { return __ebo_extract_key::_S_cget(*this); }
1288 
1289       _ExtractKey&
1290       _M_extract() { return __ebo_extract_key::_S_get(*this); }
1291 
1292       const _H1&
1293       _M_h1() const { return __ebo_h1::_S_cget(*this); }
1294 
1295       _H1&
1296       _M_h1() { return __ebo_h1::_S_get(*this); }
1297 
1298       const _H2&
1299       _M_h2() const { return __ebo_h2::_S_cget(*this); }
1300 
1301       _H2&
1302       _M_h2() { return __ebo_h2::_S_get(*this); }
1303     };
1304 
1305   /**
1306    *  Primary class template _Equal_helper.
1307    *
1308    */
1309   template <typename _Key, typename _Value, typename _ExtractKey,
1310 	    typename _Equal, typename _HashCodeType,
1311 	    bool __cache_hash_code>
1312   struct _Equal_helper;
1313 
1314   /// Specialization.
1315   template<typename _Key, typename _Value, typename _ExtractKey,
1316 	   typename _Equal, typename _HashCodeType>
1317   struct _Equal_helper<_Key, _Value, _ExtractKey, _Equal, _HashCodeType, true>
1318   {
1319     static bool
1320     _S_equals(const _Equal& __eq, const _ExtractKey& __extract,
1321 	      const _Key& __k, _HashCodeType __c, _Hash_node<_Value, true>* __n)
1322     { return __c == __n->_M_hash_code && __eq(__k, __extract(__n->_M_v())); }
1323   };
1324 
1325   /// Specialization.
1326   template<typename _Key, typename _Value, typename _ExtractKey,
1327 	   typename _Equal, typename _HashCodeType>
1328   struct _Equal_helper<_Key, _Value, _ExtractKey, _Equal, _HashCodeType, false>
1329   {
1330     static bool
1331     _S_equals(const _Equal& __eq, const _ExtractKey& __extract,
1332 	      const _Key& __k, _HashCodeType, _Hash_node<_Value, false>* __n)
1333     { return __eq(__k, __extract(__n->_M_v())); }
1334   };
1335 
1336 
1337   /// Partial specialization used when nodes contain a cached hash code.
1338   template<typename _Key, typename _Value, typename _ExtractKey,
1339 	   typename _H1, typename _H2, typename _Hash>
1340     struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1341 				_H1, _H2, _Hash, true>
1342     : private _Hashtable_ebo_helper<0, _H2>
1343     {
1344     protected:
1345       using __base_type = _Hashtable_ebo_helper<0, _H2>;
1346       using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1347 					       _H1, _H2, _Hash, true>;
1348 
1349       _Local_iterator_base() = default;
1350       _Local_iterator_base(const __hash_code_base& __base,
1351 			   _Hash_node<_Value, true>* __p,
1352 			   std::size_t __bkt, std::size_t __bkt_count)
1353       : __base_type(__base._M_h2()),
1354 	_M_cur(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count) { }
1355 
1356       void
1357       _M_incr()
1358       {
1359 	_M_cur = _M_cur->_M_next();
1360 	if (_M_cur)
1361 	  {
1362 	    std::size_t __bkt
1363 	      = __base_type::_S_get(*this)(_M_cur->_M_hash_code,
1364 					   _M_bucket_count);
1365 	    if (__bkt != _M_bucket)
1366 	      _M_cur = nullptr;
1367 	  }
1368       }
1369 
1370       _Hash_node<_Value, true>*  _M_cur;
1371       std::size_t _M_bucket;
1372       std::size_t _M_bucket_count;
1373 
1374     public:
1375       const void*
1376       _M_curr() const { return _M_cur; }  // for equality ops
1377 
1378       std::size_t
1379       _M_get_bucket() const { return _M_bucket; }  // for debug mode
1380     };
1381 
1382   // Uninitialized storage for a _Hash_code_base.
1383   // This type is DefaultConstructible and Assignable even if the
1384   // _Hash_code_base type isn't, so that _Local_iterator_base<..., false>
1385   // can be DefaultConstructible and Assignable.
1386   template<typename _Tp, bool _IsEmpty = std::is_empty<_Tp>::value>
1387     struct _Hash_code_storage
1388     {
1389       __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
1390 
1391       _Tp*
1392       _M_h() { return _M_storage._M_ptr(); }
1393 
1394       const _Tp*
1395       _M_h() const { return _M_storage._M_ptr(); }
1396     };
1397 
1398   // Empty partial specialization for empty _Hash_code_base types.
1399   template<typename _Tp>
1400     struct _Hash_code_storage<_Tp, true>
1401     {
1402       static_assert( std::is_empty<_Tp>::value, "Type must be empty" );
1403 
1404       // As _Tp is an empty type there will be no bytes written/read through
1405       // the cast pointer, so no strict-aliasing violation.
1406       _Tp*
1407       _M_h() { return reinterpret_cast<_Tp*>(this); }
1408 
1409       const _Tp*
1410       _M_h() const { return reinterpret_cast<const _Tp*>(this); }
1411     };
1412 
1413   template<typename _Key, typename _Value, typename _ExtractKey,
1414 	   typename _H1, typename _H2, typename _Hash>
1415     using __hash_code_for_local_iter
1416       = _Hash_code_storage<_Hash_code_base<_Key, _Value, _ExtractKey,
1417 					   _H1, _H2, _Hash, false>>;
1418 
1419   // Partial specialization used when hash codes are not cached
1420   template<typename _Key, typename _Value, typename _ExtractKey,
1421 	   typename _H1, typename _H2, typename _Hash>
1422     struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1423 				_H1, _H2, _Hash, false>
1424     : __hash_code_for_local_iter<_Key, _Value, _ExtractKey, _H1, _H2, _Hash>
1425     {
1426     protected:
1427       using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1428 					       _H1, _H2, _Hash, false>;
1429 
1430       _Local_iterator_base() : _M_bucket_count(-1) { }
1431 
1432       _Local_iterator_base(const __hash_code_base& __base,
1433 			   _Hash_node<_Value, false>* __p,
1434 			   std::size_t __bkt, std::size_t __bkt_count)
1435       : _M_cur(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
1436       { _M_init(__base); }
1437 
1438       ~_Local_iterator_base()
1439       {
1440 	if (_M_bucket_count != -1)
1441 	  _M_destroy();
1442       }
1443 
1444       _Local_iterator_base(const _Local_iterator_base& __iter)
1445       : _M_cur(__iter._M_cur), _M_bucket(__iter._M_bucket),
1446         _M_bucket_count(__iter._M_bucket_count)
1447       {
1448 	if (_M_bucket_count != -1)
1449 	  _M_init(*__iter._M_h());
1450       }
1451 
1452       _Local_iterator_base&
1453       operator=(const _Local_iterator_base& __iter)
1454       {
1455 	if (_M_bucket_count != -1)
1456 	  _M_destroy();
1457 	_M_cur = __iter._M_cur;
1458 	_M_bucket = __iter._M_bucket;
1459 	_M_bucket_count = __iter._M_bucket_count;
1460 	if (_M_bucket_count != -1)
1461 	  _M_init(*__iter._M_h());
1462 	return *this;
1463       }
1464 
1465       void
1466       _M_incr()
1467       {
1468 	_M_cur = _M_cur->_M_next();
1469 	if (_M_cur)
1470 	  {
1471 	    std::size_t __bkt = this->_M_h()->_M_bucket_index(_M_cur,
1472 							      _M_bucket_count);
1473 	    if (__bkt != _M_bucket)
1474 	      _M_cur = nullptr;
1475 	  }
1476       }
1477 
1478       _Hash_node<_Value, false>*  _M_cur;
1479       std::size_t _M_bucket;
1480       std::size_t _M_bucket_count;
1481 
1482       void
1483       _M_init(const __hash_code_base& __base)
1484       { ::new(this->_M_h()) __hash_code_base(__base); }
1485 
1486       void
1487       _M_destroy() { this->_M_h()->~__hash_code_base(); }
1488 
1489     public:
1490       const void*
1491       _M_curr() const { return _M_cur; }  // for equality ops and debug mode
1492 
1493       std::size_t
1494       _M_get_bucket() const { return _M_bucket; }  // for debug mode
1495     };
1496 
1497   template<typename _Key, typename _Value, typename _ExtractKey,
1498 	   typename _H1, typename _H2, typename _Hash, bool __cache>
1499     inline bool
1500     operator==(const _Local_iterator_base<_Key, _Value, _ExtractKey,
1501 					  _H1, _H2, _Hash, __cache>& __x,
1502 	       const _Local_iterator_base<_Key, _Value, _ExtractKey,
1503 					  _H1, _H2, _Hash, __cache>& __y)
1504     { return __x._M_curr() == __y._M_curr(); }
1505 
1506   template<typename _Key, typename _Value, typename _ExtractKey,
1507 	   typename _H1, typename _H2, typename _Hash, bool __cache>
1508     inline bool
1509     operator!=(const _Local_iterator_base<_Key, _Value, _ExtractKey,
1510 					  _H1, _H2, _Hash, __cache>& __x,
1511 	       const _Local_iterator_base<_Key, _Value, _ExtractKey,
1512 					  _H1, _H2, _Hash, __cache>& __y)
1513     { return __x._M_curr() != __y._M_curr(); }
1514 
1515   /// local iterators
1516   template<typename _Key, typename _Value, typename _ExtractKey,
1517 	   typename _H1, typename _H2, typename _Hash,
1518 	   bool __constant_iterators, bool __cache>
1519     struct _Local_iterator
1520     : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1521 				  _H1, _H2, _Hash, __cache>
1522     {
1523     private:
1524       using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1525 					       _H1, _H2, _Hash, __cache>;
1526       using __hash_code_base = typename __base_type::__hash_code_base;
1527     public:
1528       typedef _Value					value_type;
1529       typedef typename std::conditional<__constant_iterators,
1530 					const _Value*, _Value*>::type
1531 						       pointer;
1532       typedef typename std::conditional<__constant_iterators,
1533 					const _Value&, _Value&>::type
1534 						       reference;
1535       typedef std::ptrdiff_t				difference_type;
1536       typedef std::forward_iterator_tag			iterator_category;
1537 
1538       _Local_iterator() = default;
1539 
1540       _Local_iterator(const __hash_code_base& __base,
1541 		      _Hash_node<_Value, __cache>* __p,
1542 		      std::size_t __bkt, std::size_t __bkt_count)
1543 	: __base_type(__base, __p, __bkt, __bkt_count)
1544       { }
1545 
1546       reference
1547       operator*() const
1548       { return this->_M_cur->_M_v(); }
1549 
1550       pointer
1551       operator->() const
1552       { return this->_M_cur->_M_valptr(); }
1553 
1554       _Local_iterator&
1555       operator++()
1556       {
1557 	this->_M_incr();
1558 	return *this;
1559       }
1560 
1561       _Local_iterator
1562       operator++(int)
1563       {
1564 	_Local_iterator __tmp(*this);
1565 	this->_M_incr();
1566 	return __tmp;
1567       }
1568     };
1569 
1570   /// local const_iterators
1571   template<typename _Key, typename _Value, typename _ExtractKey,
1572 	   typename _H1, typename _H2, typename _Hash,
1573 	   bool __constant_iterators, bool __cache>
1574     struct _Local_const_iterator
1575     : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1576 				  _H1, _H2, _Hash, __cache>
1577     {
1578     private:
1579       using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1580 					       _H1, _H2, _Hash, __cache>;
1581       using __hash_code_base = typename __base_type::__hash_code_base;
1582 
1583     public:
1584       typedef _Value					value_type;
1585       typedef const _Value*				pointer;
1586       typedef const _Value&				reference;
1587       typedef std::ptrdiff_t				difference_type;
1588       typedef std::forward_iterator_tag			iterator_category;
1589 
1590       _Local_const_iterator() = default;
1591 
1592       _Local_const_iterator(const __hash_code_base& __base,
1593 			    _Hash_node<_Value, __cache>* __p,
1594 			    std::size_t __bkt, std::size_t __bkt_count)
1595 	: __base_type(__base, __p, __bkt, __bkt_count)
1596       { }
1597 
1598       _Local_const_iterator(const _Local_iterator<_Key, _Value, _ExtractKey,
1599 						  _H1, _H2, _Hash,
1600 						  __constant_iterators,
1601 						  __cache>& __x)
1602 	: __base_type(__x)
1603       { }
1604 
1605       reference
1606       operator*() const
1607       { return this->_M_cur->_M_v(); }
1608 
1609       pointer
1610       operator->() const
1611       { return this->_M_cur->_M_valptr(); }
1612 
1613       _Local_const_iterator&
1614       operator++()
1615       {
1616 	this->_M_incr();
1617 	return *this;
1618       }
1619 
1620       _Local_const_iterator
1621       operator++(int)
1622       {
1623 	_Local_const_iterator __tmp(*this);
1624 	this->_M_incr();
1625 	return __tmp;
1626       }
1627     };
1628 
1629   /**
1630    *  Primary class template _Hashtable_base.
1631    *
1632    *  Helper class adding management of _Equal functor to
1633    *  _Hash_code_base type.
1634    *
1635    *  Base class templates are:
1636    *    - __detail::_Hash_code_base
1637    *    - __detail::_Hashtable_ebo_helper
1638    */
1639   template<typename _Key, typename _Value,
1640 	   typename _ExtractKey, typename _Equal,
1641 	   typename _H1, typename _H2, typename _Hash, typename _Traits>
1642   struct _Hashtable_base
1643   : public _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash,
1644 			   _Traits::__hash_cached::value>,
1645     private _Hashtable_ebo_helper<0, _Equal>
1646   {
1647   public:
1648     typedef _Key					key_type;
1649     typedef _Value					value_type;
1650     typedef _Equal					key_equal;
1651     typedef std::size_t					size_type;
1652     typedef std::ptrdiff_t				difference_type;
1653 
1654     using __traits_type = _Traits;
1655     using __hash_cached = typename __traits_type::__hash_cached;
1656     using __constant_iterators = typename __traits_type::__constant_iterators;
1657     using __unique_keys = typename __traits_type::__unique_keys;
1658 
1659     using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1660 					     _H1, _H2, _Hash,
1661 					     __hash_cached::value>;
1662 
1663     using __hash_code = typename __hash_code_base::__hash_code;
1664     using __node_type = typename __hash_code_base::__node_type;
1665 
1666     using iterator = __detail::_Node_iterator<value_type,
1667 					      __constant_iterators::value,
1668 					      __hash_cached::value>;
1669 
1670     using const_iterator = __detail::_Node_const_iterator<value_type,
1671 						   __constant_iterators::value,
1672 						   __hash_cached::value>;
1673 
1674     using local_iterator = __detail::_Local_iterator<key_type, value_type,
1675 						  _ExtractKey, _H1, _H2, _Hash,
1676 						  __constant_iterators::value,
1677 						     __hash_cached::value>;
1678 
1679     using const_local_iterator = __detail::_Local_const_iterator<key_type,
1680 								 value_type,
1681 					_ExtractKey, _H1, _H2, _Hash,
1682 					__constant_iterators::value,
1683 					__hash_cached::value>;
1684 
1685     using __ireturn_type = typename std::conditional<__unique_keys::value,
1686 						     std::pair<iterator, bool>,
1687 						     iterator>::type;
1688   private:
1689     using _EqualEBO = _Hashtable_ebo_helper<0, _Equal>;
1690     using _EqualHelper =  _Equal_helper<_Key, _Value, _ExtractKey, _Equal,
1691 					__hash_code, __hash_cached::value>;
1692 
1693   protected:
1694     _Hashtable_base() = default;
1695     _Hashtable_base(const _ExtractKey& __ex, const _H1& __h1, const _H2& __h2,
1696 		    const _Hash& __hash, const _Equal& __eq)
1697     : __hash_code_base(__ex, __h1, __h2, __hash), _EqualEBO(__eq)
1698     { }
1699 
1700     bool
1701     _M_equals(const _Key& __k, __hash_code __c, __node_type* __n) const
1702     {
1703       return _EqualHelper::_S_equals(_M_eq(), this->_M_extract(),
1704 				     __k, __c, __n);
1705     }
1706 
1707     void
1708     _M_swap(_Hashtable_base& __x)
1709     {
1710       __hash_code_base::_M_swap(__x);
1711       std::swap(_M_eq(), __x._M_eq());
1712     }
1713 
1714     const _Equal&
1715     _M_eq() const { return _EqualEBO::_S_cget(*this); }
1716 
1717     _Equal&
1718     _M_eq() { return _EqualEBO::_S_get(*this); }
1719   };
1720 
1721   /**
1722    *  struct _Equality_base.
1723    *
1724    *  Common types and functions for class _Equality.
1725    */
1726   struct _Equality_base
1727   {
1728   protected:
1729     template<typename _Uiterator>
1730       static bool
1731       _S_is_permutation(_Uiterator, _Uiterator, _Uiterator);
1732   };
1733 
1734   // See std::is_permutation in N3068.
1735   template<typename _Uiterator>
1736     bool
1737     _Equality_base::
1738     _S_is_permutation(_Uiterator __first1, _Uiterator __last1,
1739 		      _Uiterator __first2)
1740     {
1741       for (; __first1 != __last1; ++__first1, ++__first2)
1742 	if (!(*__first1 == *__first2))
1743 	  break;
1744 
1745       if (__first1 == __last1)
1746 	return true;
1747 
1748       _Uiterator __last2 = __first2;
1749       std::advance(__last2, std::distance(__first1, __last1));
1750 
1751       for (_Uiterator __it1 = __first1; __it1 != __last1; ++__it1)
1752 	{
1753 	  _Uiterator __tmp =  __first1;
1754 	  while (__tmp != __it1 && !bool(*__tmp == *__it1))
1755 	    ++__tmp;
1756 
1757 	  // We've seen this one before.
1758 	  if (__tmp != __it1)
1759 	    continue;
1760 
1761 	  std::ptrdiff_t __n2 = 0;
1762 	  for (__tmp = __first2; __tmp != __last2; ++__tmp)
1763 	    if (*__tmp == *__it1)
1764 	      ++__n2;
1765 
1766 	  if (!__n2)
1767 	    return false;
1768 
1769 	  std::ptrdiff_t __n1 = 0;
1770 	  for (__tmp = __it1; __tmp != __last1; ++__tmp)
1771 	    if (*__tmp == *__it1)
1772 	      ++__n1;
1773 
1774 	  if (__n1 != __n2)
1775 	    return false;
1776 	}
1777       return true;
1778     }
1779 
1780   /**
1781    *  Primary class template  _Equality.
1782    *
1783    *  This is for implementing equality comparison for unordered
1784    *  containers, per N3068, by John Lakos and Pablo Halpern.
1785    *  Algorithmically, we follow closely the reference implementations
1786    *  therein.
1787    */
1788   template<typename _Key, typename _Value, typename _Alloc,
1789 	   typename _ExtractKey, typename _Equal,
1790 	   typename _H1, typename _H2, typename _Hash,
1791 	   typename _RehashPolicy, typename _Traits,
1792 	   bool _Unique_keys = _Traits::__unique_keys::value>
1793     struct _Equality;
1794 
1795   /// Specialization.
1796   template<typename _Key, typename _Value, typename _Alloc,
1797 	   typename _ExtractKey, typename _Equal,
1798 	   typename _H1, typename _H2, typename _Hash,
1799 	   typename _RehashPolicy, typename _Traits>
1800     struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1801 		     _H1, _H2, _Hash, _RehashPolicy, _Traits, true>
1802     {
1803       using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1804 				     _H1, _H2, _Hash, _RehashPolicy, _Traits>;
1805 
1806       bool
1807       _M_equal(const __hashtable&) const;
1808     };
1809 
1810   template<typename _Key, typename _Value, typename _Alloc,
1811 	   typename _ExtractKey, typename _Equal,
1812 	   typename _H1, typename _H2, typename _Hash,
1813 	   typename _RehashPolicy, typename _Traits>
1814     bool
1815     _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1816 	      _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
1817     _M_equal(const __hashtable& __other) const
1818     {
1819       const __hashtable* __this = static_cast<const __hashtable*>(this);
1820 
1821       if (__this->size() != __other.size())
1822 	return false;
1823 
1824       for (auto __itx = __this->begin(); __itx != __this->end(); ++__itx)
1825 	{
1826 	  const auto __ity = __other.find(_ExtractKey()(*__itx));
1827 	  if (__ity == __other.end() || !bool(*__ity == *__itx))
1828 	    return false;
1829 	}
1830       return true;
1831     }
1832 
1833   /// Specialization.
1834   template<typename _Key, typename _Value, typename _Alloc,
1835 	   typename _ExtractKey, typename _Equal,
1836 	   typename _H1, typename _H2, typename _Hash,
1837 	   typename _RehashPolicy, typename _Traits>
1838     struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1839 		     _H1, _H2, _Hash, _RehashPolicy, _Traits, false>
1840     : public _Equality_base
1841     {
1842       using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1843 				     _H1, _H2, _Hash, _RehashPolicy, _Traits>;
1844 
1845       bool
1846       _M_equal(const __hashtable&) const;
1847     };
1848 
1849   template<typename _Key, typename _Value, typename _Alloc,
1850 	   typename _ExtractKey, typename _Equal,
1851 	   typename _H1, typename _H2, typename _Hash,
1852 	   typename _RehashPolicy, typename _Traits>
1853     bool
1854     _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1855 	      _H1, _H2, _Hash, _RehashPolicy, _Traits, false>::
1856     _M_equal(const __hashtable& __other) const
1857     {
1858       const __hashtable* __this = static_cast<const __hashtable*>(this);
1859 
1860       if (__this->size() != __other.size())
1861 	return false;
1862 
1863       for (auto __itx = __this->begin(); __itx != __this->end();)
1864 	{
1865 	  const auto __xrange = __this->equal_range(_ExtractKey()(*__itx));
1866 	  const auto __yrange = __other.equal_range(_ExtractKey()(*__itx));
1867 
1868 	  if (std::distance(__xrange.first, __xrange.second)
1869 	      != std::distance(__yrange.first, __yrange.second))
1870 	    return false;
1871 
1872 	  if (!_S_is_permutation(__xrange.first, __xrange.second,
1873 				 __yrange.first))
1874 	    return false;
1875 
1876 	  __itx = __xrange.second;
1877 	}
1878       return true;
1879     }
1880 
1881   /**
1882    * This type deals with all allocation and keeps an allocator instance through
1883    * inheritance to benefit from EBO when possible.
1884    */
1885   template<typename _NodeAlloc>
1886     struct _Hashtable_alloc : private _Hashtable_ebo_helper<0, _NodeAlloc>
1887     {
1888     private:
1889       using __ebo_node_alloc = _Hashtable_ebo_helper<0, _NodeAlloc>;
1890     public:
1891       using __node_type = typename _NodeAlloc::value_type;
1892       using __node_alloc_type = _NodeAlloc;
1893       // Use __gnu_cxx to benefit from _S_always_equal and al.
1894       using __node_alloc_traits = __gnu_cxx::__alloc_traits<__node_alloc_type>;
1895 
1896       using __value_type = typename __node_type::value_type;
1897       using __value_alloc_type =
1898 	__alloc_rebind<__node_alloc_type, __value_type>;
1899       using __value_alloc_traits = std::allocator_traits<__value_alloc_type>;
1900 
1901       using __node_base = __detail::_Hash_node_base;
1902       using __bucket_type = __node_base*;
1903       using __bucket_alloc_type =
1904 	__alloc_rebind<__node_alloc_type, __bucket_type>;
1905       using __bucket_alloc_traits = std::allocator_traits<__bucket_alloc_type>;
1906 
1907       _Hashtable_alloc() = default;
1908       _Hashtable_alloc(const _Hashtable_alloc&) = default;
1909       _Hashtable_alloc(_Hashtable_alloc&&) = default;
1910 
1911       template<typename _Alloc>
1912 	_Hashtable_alloc(_Alloc&& __a)
1913 	  : __ebo_node_alloc(std::forward<_Alloc>(__a))
1914 	{ }
1915 
1916       __node_alloc_type&
1917       _M_node_allocator()
1918       { return __ebo_node_alloc::_S_get(*this); }
1919 
1920       const __node_alloc_type&
1921       _M_node_allocator() const
1922       { return __ebo_node_alloc::_S_cget(*this); }
1923 
1924       template<typename... _Args>
1925 	__node_type*
1926 	_M_allocate_node(_Args&&... __args);
1927 
1928       void
1929       _M_deallocate_node(__node_type* __n);
1930 
1931       // Deallocate the linked list of nodes pointed to by __n
1932       void
1933       _M_deallocate_nodes(__node_type* __n);
1934 
1935       __bucket_type*
1936       _M_allocate_buckets(std::size_t __n);
1937 
1938       void
1939       _M_deallocate_buckets(__bucket_type*, std::size_t __n);
1940     };
1941 
1942   // Definitions of class template _Hashtable_alloc's out-of-line member
1943   // functions.
1944   template<typename _NodeAlloc>
1945     template<typename... _Args>
1946       typename _Hashtable_alloc<_NodeAlloc>::__node_type*
1947       _Hashtable_alloc<_NodeAlloc>::_M_allocate_node(_Args&&... __args)
1948       {
1949 	auto __nptr = __node_alloc_traits::allocate(_M_node_allocator(), 1);
1950 	__node_type* __n = std::__addressof(*__nptr);
1951 	__try
1952 	  {
1953 	    __value_alloc_type __a(_M_node_allocator());
1954 	    ::new ((void*)__n) __node_type;
1955 	    __value_alloc_traits::construct(__a, __n->_M_valptr(),
1956 					    std::forward<_Args>(__args)...);
1957 	    return __n;
1958 	  }
1959 	__catch(...)
1960 	  {
1961 	    __node_alloc_traits::deallocate(_M_node_allocator(), __nptr, 1);
1962 	    __throw_exception_again;
1963 	  }
1964       }
1965 
1966   template<typename _NodeAlloc>
1967     void
1968     _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node(__node_type* __n)
1969     {
1970       typedef typename __node_alloc_traits::pointer _Ptr;
1971       auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__n);
1972       __value_alloc_type __a(_M_node_allocator());
1973       __value_alloc_traits::destroy(__a, __n->_M_valptr());
1974       __n->~__node_type();
1975       __node_alloc_traits::deallocate(_M_node_allocator(), __ptr, 1);
1976     }
1977 
1978   template<typename _NodeAlloc>
1979     void
1980     _Hashtable_alloc<_NodeAlloc>::_M_deallocate_nodes(__node_type* __n)
1981     {
1982       while (__n)
1983 	{
1984 	  __node_type* __tmp = __n;
1985 	  __n = __n->_M_next();
1986 	  _M_deallocate_node(__tmp);
1987 	}
1988     }
1989 
1990   template<typename _NodeAlloc>
1991     typename _Hashtable_alloc<_NodeAlloc>::__bucket_type*
1992     _Hashtable_alloc<_NodeAlloc>::_M_allocate_buckets(std::size_t __n)
1993     {
1994       __bucket_alloc_type __alloc(_M_node_allocator());
1995 
1996       auto __ptr = __bucket_alloc_traits::allocate(__alloc, __n);
1997       __bucket_type* __p = std::__addressof(*__ptr);
1998       __builtin_memset(__p, 0, __n * sizeof(__bucket_type));
1999       return __p;
2000     }
2001 
2002   template<typename _NodeAlloc>
2003     void
2004     _Hashtable_alloc<_NodeAlloc>::_M_deallocate_buckets(__bucket_type* __bkts,
2005 							std::size_t __n)
2006     {
2007       typedef typename __bucket_alloc_traits::pointer _Ptr;
2008       auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__bkts);
2009       __bucket_alloc_type __alloc(_M_node_allocator());
2010       __bucket_alloc_traits::deallocate(__alloc, __ptr, __n);
2011     }
2012 
2013  //@} hashtable-detail
2014 _GLIBCXX_END_NAMESPACE_VERSION
2015 } // namespace __detail
2016 } // namespace std
2017 
2018 #endif // _HASHTABLE_POLICY_H
2019