1 // Internal policy header for unordered_set and unordered_map -*- C++ -*-
2
3 // Copyright (C) 2010-2020 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 <limits> // for std::numeric_limits
36 #include <bits/stl_algobase.h> // for std::min, std::is_permutation.
37
_GLIBCXX_VISIBILITY(default)38 namespace std _GLIBCXX_VISIBILITY(default)
39 {
40 _GLIBCXX_BEGIN_NAMESPACE_VERSION
41
42 template<typename _Key, typename _Value, typename _Alloc,
43 typename _ExtractKey, typename _Equal,
44 typename _H1, typename _H2, typename _Hash,
45 typename _RehashPolicy, typename _Traits>
46 class _Hashtable;
47
48 namespace __detail
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 0/1 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 __first != __last ? 1 : 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 { return __distance_fw(__first, __last,
78 std::__iterator_category(__first)); }
79
80 struct _Identity
81 {
82 template<typename _Tp>
83 _Tp&&
84 operator()(_Tp&& __x) const
85 { return std::forward<_Tp>(__x); }
86 };
87
88 struct _Select1st
89 {
90 template<typename _Tp>
91 auto
92 operator()(_Tp&& __x) const
93 -> decltype(std::get<0>(std::forward<_Tp>(__x)))
94 { return std::get<0>(std::forward<_Tp>(__x)); }
95 };
96
97 template<typename _NodeAlloc>
98 struct _Hashtable_alloc;
99
100 // Functor recycling a pool of nodes and using allocation once the pool is
101 // empty.
102 template<typename _NodeAlloc>
103 struct _ReuseOrAllocNode
104 {
105 private:
106 using __node_alloc_type = _NodeAlloc;
107 using __hashtable_alloc = _Hashtable_alloc<__node_alloc_type>;
108 using __node_alloc_traits =
109 typename __hashtable_alloc::__node_alloc_traits;
110 using __node_type = typename __hashtable_alloc::__node_type;
111
112 public:
113 _ReuseOrAllocNode(__node_type* __nodes, __hashtable_alloc& __h)
114 : _M_nodes(__nodes), _M_h(__h) { }
115 _ReuseOrAllocNode(const _ReuseOrAllocNode&) = delete;
116
117 ~_ReuseOrAllocNode()
118 { _M_h._M_deallocate_nodes(_M_nodes); }
119
120 template<typename _Arg>
121 __node_type*
122 operator()(_Arg&& __arg) const
123 {
124 if (_M_nodes)
125 {
126 __node_type* __node = _M_nodes;
127 _M_nodes = _M_nodes->_M_next();
128 __node->_M_nxt = nullptr;
129 auto& __a = _M_h._M_node_allocator();
130 __node_alloc_traits::destroy(__a, __node->_M_valptr());
131 __try
132 {
133 __node_alloc_traits::construct(__a, __node->_M_valptr(),
134 std::forward<_Arg>(__arg));
135 }
136 __catch(...)
137 {
138 _M_h._M_deallocate_node_ptr(__node);
139 __throw_exception_again;
140 }
141 return __node;
142 }
143 return _M_h._M_allocate_node(std::forward<_Arg>(__arg));
144 }
145
146 private:
147 mutable __node_type* _M_nodes;
148 __hashtable_alloc& _M_h;
149 };
150
151 // Functor similar to the previous one but without any pool of nodes to
152 // recycle.
153 template<typename _NodeAlloc>
154 struct _AllocNode
155 {
156 private:
157 using __hashtable_alloc = _Hashtable_alloc<_NodeAlloc>;
158 using __node_type = typename __hashtable_alloc::__node_type;
159
160 public:
161 _AllocNode(__hashtable_alloc& __h)
162 : _M_h(__h) { }
163
164 template<typename _Arg>
165 __node_type*
166 operator()(_Arg&& __arg) const
167 { return _M_h._M_allocate_node(std::forward<_Arg>(__arg)); }
168
169 private:
170 __hashtable_alloc& _M_h;
171 };
172
173 // Auxiliary types used for all instantiations of _Hashtable nodes
174 // and iterators.
175
176 /**
177 * struct _Hashtable_traits
178 *
179 * Important traits for hash tables.
180 *
181 * @tparam _Cache_hash_code Boolean value. True if the value of
182 * the hash function is stored along with the value. This is a
183 * time-space tradeoff. Storing it may improve lookup speed by
184 * reducing the number of times we need to call the _Hash or _Equal
185 * functors.
186 *
187 * @tparam _Constant_iterators Boolean value. True if iterator and
188 * const_iterator are both constant iterator types. This is true
189 * for unordered_set and unordered_multiset, false for
190 * unordered_map and unordered_multimap.
191 *
192 * @tparam _Unique_keys Boolean value. True if the return value
193 * of _Hashtable::count(k) is always at most one, false if it may
194 * be an arbitrary number. This is true for unordered_set and
195 * unordered_map, false for unordered_multiset and
196 * unordered_multimap.
197 */
198 template<bool _Cache_hash_code, bool _Constant_iterators, bool _Unique_keys>
199 struct _Hashtable_traits
200 {
201 using __hash_cached = __bool_constant<_Cache_hash_code>;
202 using __constant_iterators = __bool_constant<_Constant_iterators>;
203 using __unique_keys = __bool_constant<_Unique_keys>;
204 };
205
206 /**
207 * struct _Hash_node_base
208 *
209 * Nodes, used to wrap elements stored in the hash table. A policy
210 * template parameter of class template _Hashtable controls whether
211 * nodes also store a hash code. In some cases (e.g. strings) this
212 * may be a performance win.
213 */
214 struct _Hash_node_base
215 {
216 _Hash_node_base* _M_nxt;
217
218 _Hash_node_base() noexcept : _M_nxt() { }
219
220 _Hash_node_base(_Hash_node_base* __next) noexcept : _M_nxt(__next) { }
221 };
222
223 /**
224 * struct _Hash_node_value_base
225 *
226 * Node type with the value to store.
227 */
228 template<typename _Value>
229 struct _Hash_node_value_base : _Hash_node_base
230 {
231 typedef _Value value_type;
232
233 __gnu_cxx::__aligned_buffer<_Value> _M_storage;
234
235 _Value*
236 _M_valptr() noexcept
237 { return _M_storage._M_ptr(); }
238
239 const _Value*
240 _M_valptr() const noexcept
241 { return _M_storage._M_ptr(); }
242
243 _Value&
244 _M_v() noexcept
245 { return *_M_valptr(); }
246
247 const _Value&
248 _M_v() const noexcept
249 { return *_M_valptr(); }
250 };
251
252 /**
253 * Primary template struct _Hash_node.
254 */
255 template<typename _Value, bool _Cache_hash_code>
256 struct _Hash_node;
257
258 /**
259 * Specialization for nodes with caches, struct _Hash_node.
260 *
261 * Base class is __detail::_Hash_node_value_base.
262 */
263 template<typename _Value>
264 struct _Hash_node<_Value, true> : _Hash_node_value_base<_Value>
265 {
266 std::size_t _M_hash_code;
267
268 _Hash_node*
269 _M_next() const noexcept
270 { return static_cast<_Hash_node*>(this->_M_nxt); }
271 };
272
273 /**
274 * Specialization for nodes without caches, struct _Hash_node.
275 *
276 * Base class is __detail::_Hash_node_value_base.
277 */
278 template<typename _Value>
279 struct _Hash_node<_Value, false> : _Hash_node_value_base<_Value>
280 {
281 _Hash_node*
282 _M_next() const noexcept
283 { return static_cast<_Hash_node*>(this->_M_nxt); }
284 };
285
286 /// Base class for node iterators.
287 template<typename _Value, bool _Cache_hash_code>
288 struct _Node_iterator_base
289 {
290 using __node_type = _Hash_node<_Value, _Cache_hash_code>;
291
292 __node_type* _M_cur;
293
294 _Node_iterator_base(__node_type* __p) noexcept
295 : _M_cur(__p) { }
296
297 void
298 _M_incr() noexcept
299 { _M_cur = _M_cur->_M_next(); }
300 };
301
302 template<typename _Value, bool _Cache_hash_code>
303 inline bool
304 operator==(const _Node_iterator_base<_Value, _Cache_hash_code>& __x,
305 const _Node_iterator_base<_Value, _Cache_hash_code >& __y)
306 noexcept
307 { return __x._M_cur == __y._M_cur; }
308
309 template<typename _Value, bool _Cache_hash_code>
310 inline bool
311 operator!=(const _Node_iterator_base<_Value, _Cache_hash_code>& __x,
312 const _Node_iterator_base<_Value, _Cache_hash_code>& __y)
313 noexcept
314 { return __x._M_cur != __y._M_cur; }
315
316 /// Node iterators, used to iterate through all the hashtable.
317 template<typename _Value, bool __constant_iterators, bool __cache>
318 struct _Node_iterator
319 : public _Node_iterator_base<_Value, __cache>
320 {
321 private:
322 using __base_type = _Node_iterator_base<_Value, __cache>;
323 using __node_type = typename __base_type::__node_type;
324
325 public:
326 typedef _Value value_type;
327 typedef std::ptrdiff_t difference_type;
328 typedef std::forward_iterator_tag iterator_category;
329
330 using pointer = typename std::conditional<__constant_iterators,
331 const _Value*, _Value*>::type;
332
333 using reference = typename std::conditional<__constant_iterators,
334 const _Value&, _Value&>::type;
335
336 _Node_iterator() noexcept
337 : __base_type(0) { }
338
339 explicit
340 _Node_iterator(__node_type* __p) noexcept
341 : __base_type(__p) { }
342
343 reference
344 operator*() const noexcept
345 { return this->_M_cur->_M_v(); }
346
347 pointer
348 operator->() const noexcept
349 { return this->_M_cur->_M_valptr(); }
350
351 _Node_iterator&
352 operator++() noexcept
353 {
354 this->_M_incr();
355 return *this;
356 }
357
358 _Node_iterator
359 operator++(int) noexcept
360 {
361 _Node_iterator __tmp(*this);
362 this->_M_incr();
363 return __tmp;
364 }
365 };
366
367 /// Node const_iterators, used to iterate through all the hashtable.
368 template<typename _Value, bool __constant_iterators, bool __cache>
369 struct _Node_const_iterator
370 : public _Node_iterator_base<_Value, __cache>
371 {
372 private:
373 using __base_type = _Node_iterator_base<_Value, __cache>;
374 using __node_type = typename __base_type::__node_type;
375
376 public:
377 typedef _Value value_type;
378 typedef std::ptrdiff_t difference_type;
379 typedef std::forward_iterator_tag iterator_category;
380
381 typedef const _Value* pointer;
382 typedef const _Value& reference;
383
384 _Node_const_iterator() noexcept
385 : __base_type(0) { }
386
387 explicit
388 _Node_const_iterator(__node_type* __p) noexcept
389 : __base_type(__p) { }
390
391 _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators,
392 __cache>& __x) noexcept
393 : __base_type(__x._M_cur) { }
394
395 reference
396 operator*() const noexcept
397 { return this->_M_cur->_M_v(); }
398
399 pointer
400 operator->() const noexcept
401 { return this->_M_cur->_M_valptr(); }
402
403 _Node_const_iterator&
404 operator++() noexcept
405 {
406 this->_M_incr();
407 return *this;
408 }
409
410 _Node_const_iterator
411 operator++(int) noexcept
412 {
413 _Node_const_iterator __tmp(*this);
414 this->_M_incr();
415 return __tmp;
416 }
417 };
418
419 // Many of class template _Hashtable's template parameters are policy
420 // classes. These are defaults for the policies.
421
422 /// Default range hashing function: use division to fold a large number
423 /// into the range [0, N).
424 struct _Mod_range_hashing
425 {
426 typedef std::size_t first_argument_type;
427 typedef std::size_t second_argument_type;
428 typedef std::size_t result_type;
429
430 result_type
431 operator()(first_argument_type __num,
432 second_argument_type __den) const noexcept
433 { return __num % __den; }
434 };
435
436 /// Default ranged hash function H. In principle it should be a
437 /// function object composed from objects of type H1 and H2 such that
438 /// h(k, N) = h2(h1(k), N), but that would mean making extra copies of
439 /// h1 and h2. So instead we'll just use a tag to tell class template
440 /// hashtable to do that composition.
441 struct _Default_ranged_hash { };
442
443 /// Default value for rehash policy. Bucket size is (usually) the
444 /// smallest prime that keeps the load factor small enough.
445 struct _Prime_rehash_policy
446 {
447 using __has_load_factor = true_type;
448
449 _Prime_rehash_policy(float __z = 1.0) noexcept
450 : _M_max_load_factor(__z), _M_next_resize(0) { }
451
452 float
453 max_load_factor() const noexcept
454 { return _M_max_load_factor; }
455
456 // Return a bucket size no smaller than n.
457 std::size_t
458 _M_next_bkt(std::size_t __n) const;
459
460 // Return a bucket count appropriate for n elements
461 std::size_t
462 _M_bkt_for_elements(std::size_t __n) const
463 { return __builtin_ceill(__n / (long double)_M_max_load_factor); }
464
465 // __n_bkt is current bucket count, __n_elt is current element count,
466 // and __n_ins is number of elements to be inserted. Do we need to
467 // increase bucket count? If so, return make_pair(true, n), where n
468 // is the new bucket count. If not, return make_pair(false, 0).
469 std::pair<bool, std::size_t>
470 _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
471 std::size_t __n_ins) const;
472
473 typedef std::size_t _State;
474
475 _State
476 _M_state() const
477 { return _M_next_resize; }
478
479 void
480 _M_reset() noexcept
481 { _M_next_resize = 0; }
482
483 void
484 _M_reset(_State __state)
485 { _M_next_resize = __state; }
486
487 static const std::size_t _S_growth_factor = 2;
488
489 float _M_max_load_factor;
490 mutable std::size_t _M_next_resize;
491 };
492
493 /// Range hashing function assuming that second arg is a power of 2.
494 struct _Mask_range_hashing
495 {
496 typedef std::size_t first_argument_type;
497 typedef std::size_t second_argument_type;
498 typedef std::size_t result_type;
499
500 result_type
501 operator()(first_argument_type __num,
502 second_argument_type __den) const noexcept
503 { return __num & (__den - 1); }
504 };
505
506 /// Compute closest power of 2 not less than __n
507 inline std::size_t
508 __clp2(std::size_t __n) noexcept
509 {
510 // Equivalent to return __n ? std::bit_ceil(__n) : 0;
511 if (__n < 2)
512 return __n;
513 const unsigned __lz = sizeof(size_t) > sizeof(long)
514 ? __builtin_clzll(__n - 1ull)
515 : __builtin_clzl(__n - 1ul);
516 // Doing two shifts avoids undefined behaviour when __lz == 0.
517 return (size_t(1) << (numeric_limits<size_t>::digits - __lz - 1)) << 1;
518 }
519
520 /// Rehash policy providing power of 2 bucket numbers. Avoids modulo
521 /// operations.
522 struct _Power2_rehash_policy
523 {
524 using __has_load_factor = true_type;
525
526 _Power2_rehash_policy(float __z = 1.0) noexcept
527 : _M_max_load_factor(__z), _M_next_resize(0) { }
528
529 float
530 max_load_factor() const noexcept
531 { return _M_max_load_factor; }
532
533 // Return a bucket size no smaller than n (as long as n is not above the
534 // highest power of 2).
535 std::size_t
536 _M_next_bkt(std::size_t __n) noexcept
537 {
538 if (__n == 0)
539 // Special case on container 1st initialization with 0 bucket count
540 // hint. We keep _M_next_resize to 0 to make sure that next time we
541 // want to add an element allocation will take place.
542 return 1;
543
544 const auto __max_width = std::min<size_t>(sizeof(size_t), 8);
545 const auto __max_bkt = size_t(1) << (__max_width * __CHAR_BIT__ - 1);
546 std::size_t __res = __clp2(__n);
547
548 if (__res == 0)
549 __res = __max_bkt;
550 else if (__res == 1)
551 // If __res is 1 we force it to 2 to make sure there will be an
552 // allocation so that nothing need to be stored in the initial
553 // single bucket
554 __res = 2;
555
556 if (__res == __max_bkt)
557 // Set next resize to the max value so that we never try to rehash again
558 // as we already reach the biggest possible bucket number.
559 // Note that it might result in max_load_factor not being respected.
560 _M_next_resize = numeric_limits<size_t>::max();
561 else
562 _M_next_resize
563 = __builtin_floorl(__res * (long double)_M_max_load_factor);
564
565 return __res;
566 }
567
568 // Return a bucket count appropriate for n elements
569 std::size_t
570 _M_bkt_for_elements(std::size_t __n) const noexcept
571 { return __builtin_ceill(__n / (long double)_M_max_load_factor); }
572
573 // __n_bkt is current bucket count, __n_elt is current element count,
574 // and __n_ins is number of elements to be inserted. Do we need to
575 // increase bucket count? If so, return make_pair(true, n), where n
576 // is the new bucket count. If not, return make_pair(false, 0).
577 std::pair<bool, std::size_t>
578 _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
579 std::size_t __n_ins) noexcept
580 {
581 if (__n_elt + __n_ins > _M_next_resize)
582 {
583 // If _M_next_resize is 0 it means that we have nothing allocated so
584 // far and that we start inserting elements. In this case we start
585 // with an initial bucket size of 11.
586 long double __min_bkts
587 = std::max<std::size_t>(__n_elt + __n_ins, _M_next_resize ? 0 : 11)
588 / (long double)_M_max_load_factor;
589 if (__min_bkts >= __n_bkt)
590 return { true,
591 _M_next_bkt(std::max<std::size_t>(__builtin_floorl(__min_bkts) + 1,
592 __n_bkt * _S_growth_factor)) };
593
594 _M_next_resize
595 = __builtin_floorl(__n_bkt * (long double)_M_max_load_factor);
596 return { false, 0 };
597 }
598 else
599 return { false, 0 };
600 }
601
602 typedef std::size_t _State;
603
604 _State
605 _M_state() const noexcept
606 { return _M_next_resize; }
607
608 void
609 _M_reset() noexcept
610 { _M_next_resize = 0; }
611
612 void
613 _M_reset(_State __state) noexcept
614 { _M_next_resize = __state; }
615
616 static const std::size_t _S_growth_factor = 2;
617
618 float _M_max_load_factor;
619 std::size_t _M_next_resize;
620 };
621
622 // Base classes for std::_Hashtable. We define these base classes
623 // because in some cases we want to do different things depending on
624 // the value of a policy class. In some cases the policy class
625 // affects which member functions and nested typedefs are defined;
626 // we handle that by specializing base class templates. Several of
627 // the base class templates need to access other members of class
628 // template _Hashtable, so we use a variant of the "Curiously
629 // Recurring Template Pattern" (CRTP) technique.
630
631 /**
632 * Primary class template _Map_base.
633 *
634 * If the hashtable has a value type of the form pair<T1, T2> and a
635 * key extraction policy (_ExtractKey) that returns the first part
636 * of the pair, the hashtable gets a mapped_type typedef. If it
637 * satisfies those criteria and also has unique keys, then it also
638 * gets an operator[].
639 */
640 template<typename _Key, typename _Value, typename _Alloc,
641 typename _ExtractKey, typename _Equal,
642 typename _H1, typename _H2, typename _Hash,
643 typename _RehashPolicy, typename _Traits,
644 bool _Unique_keys = _Traits::__unique_keys::value>
645 struct _Map_base { };
646
647 /// Partial specialization, __unique_keys set to false.
648 template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
649 typename _H1, typename _H2, typename _Hash,
650 typename _RehashPolicy, typename _Traits>
651 struct _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
652 _H1, _H2, _Hash, _RehashPolicy, _Traits, false>
653 {
654 using mapped_type = typename std::tuple_element<1, _Pair>::type;
655 };
656
657 /// Partial specialization, __unique_keys set to true.
658 template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
659 typename _H1, typename _H2, typename _Hash,
660 typename _RehashPolicy, typename _Traits>
661 struct _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
662 _H1, _H2, _Hash, _RehashPolicy, _Traits, true>
663 {
664 private:
665 using __hashtable_base = __detail::_Hashtable_base<_Key, _Pair,
666 _Select1st,
667 _Equal, _H1, _H2, _Hash,
668 _Traits>;
669
670 using __hashtable = _Hashtable<_Key, _Pair, _Alloc,
671 _Select1st, _Equal,
672 _H1, _H2, _Hash, _RehashPolicy, _Traits>;
673
674 using __hash_code = typename __hashtable_base::__hash_code;
675 using __node_type = typename __hashtable_base::__node_type;
676
677 public:
678 using key_type = typename __hashtable_base::key_type;
679 using iterator = typename __hashtable_base::iterator;
680 using mapped_type = typename std::tuple_element<1, _Pair>::type;
681
682 mapped_type&
683 operator[](const key_type& __k);
684
685 mapped_type&
686 operator[](key_type&& __k);
687
688 // _GLIBCXX_RESOLVE_LIB_DEFECTS
689 // DR 761. unordered_map needs an at() member function.
690 mapped_type&
691 at(const key_type& __k);
692
693 const mapped_type&
694 at(const key_type& __k) const;
695 };
696
697 template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
698 typename _H1, typename _H2, typename _Hash,
699 typename _RehashPolicy, typename _Traits>
700 auto
701 _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
702 _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
703 operator[](const key_type& __k)
704 -> mapped_type&
705 {
706 __hashtable* __h = static_cast<__hashtable*>(this);
707 __hash_code __code = __h->_M_hash_code(__k);
708 std::size_t __bkt = __h->_M_bucket_index(__k, __code);
709 if (__node_type* __node = __h->_M_find_node(__bkt, __k, __code))
710 return __node->_M_v().second;
711
712 typename __hashtable::_Scoped_node __node {
713 __h,
714 std::piecewise_construct,
715 std::tuple<const key_type&>(__k),
716 std::tuple<>()
717 };
718 auto __pos
719 = __h->_M_insert_unique_node(__k, __bkt, __code, __node._M_node);
720 __node._M_node = nullptr;
721 return __pos->second;
722 }
723
724 template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
725 typename _H1, typename _H2, typename _Hash,
726 typename _RehashPolicy, typename _Traits>
727 auto
728 _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
729 _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
730 operator[](key_type&& __k)
731 -> mapped_type&
732 {
733 __hashtable* __h = static_cast<__hashtable*>(this);
734 __hash_code __code = __h->_M_hash_code(__k);
735 std::size_t __bkt = __h->_M_bucket_index(__k, __code);
736 if (__node_type* __node = __h->_M_find_node(__bkt, __k, __code))
737 return __node->_M_v().second;
738
739 typename __hashtable::_Scoped_node __node {
740 __h,
741 std::piecewise_construct,
742 std::forward_as_tuple(std::move(__k)),
743 std::tuple<>()
744 };
745 auto __pos
746 = __h->_M_insert_unique_node(__k, __bkt, __code, __node._M_node);
747 __node._M_node = nullptr;
748 return __pos->second;
749 }
750
751 template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
752 typename _H1, typename _H2, typename _Hash,
753 typename _RehashPolicy, typename _Traits>
754 auto
755 _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
756 _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
757 at(const key_type& __k)
758 -> mapped_type&
759 {
760 __hashtable* __h = static_cast<__hashtable*>(this);
761 __hash_code __code = __h->_M_hash_code(__k);
762 std::size_t __bkt = __h->_M_bucket_index(__k, __code);
763 __node_type* __p = __h->_M_find_node(__bkt, __k, __code);
764
765 if (!__p)
766 __throw_out_of_range(__N("_Map_base::at"));
767 return __p->_M_v().second;
768 }
769
770 template<typename _Key, typename _Pair, typename _Alloc, typename _Equal,
771 typename _H1, typename _H2, typename _Hash,
772 typename _RehashPolicy, typename _Traits>
773 auto
774 _Map_base<_Key, _Pair, _Alloc, _Select1st, _Equal,
775 _H1, _H2, _Hash, _RehashPolicy, _Traits, true>::
776 at(const key_type& __k) const
777 -> const mapped_type&
778 {
779 const __hashtable* __h = static_cast<const __hashtable*>(this);
780 __hash_code __code = __h->_M_hash_code(__k);
781 std::size_t __bkt = __h->_M_bucket_index(__k, __code);
782 __node_type* __p = __h->_M_find_node(__bkt, __k, __code);
783
784 if (!__p)
785 __throw_out_of_range(__N("_Map_base::at"));
786 return __p->_M_v().second;
787 }
788
789 /**
790 * Primary class template _Insert_base.
791 *
792 * Defines @c insert member functions appropriate to all _Hashtables.
793 */
794 template<typename _Key, typename _Value, typename _Alloc,
795 typename _ExtractKey, typename _Equal,
796 typename _H1, typename _H2, typename _Hash,
797 typename _RehashPolicy, typename _Traits>
798 struct _Insert_base
799 {
800 protected:
801 using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
802 _Equal, _H1, _H2, _Hash,
803 _RehashPolicy, _Traits>;
804
805 using __hashtable_base = _Hashtable_base<_Key, _Value, _ExtractKey,
806 _Equal, _H1, _H2, _Hash,
807 _Traits>;
808
809 using value_type = typename __hashtable_base::value_type;
810 using iterator = typename __hashtable_base::iterator;
811 using const_iterator = typename __hashtable_base::const_iterator;
812 using size_type = typename __hashtable_base::size_type;
813
814 using __unique_keys = typename __hashtable_base::__unique_keys;
815 using __ireturn_type = typename __hashtable_base::__ireturn_type;
816 using __node_type = _Hash_node<_Value, _Traits::__hash_cached::value>;
817 using __node_alloc_type = __alloc_rebind<_Alloc, __node_type>;
818 using __node_gen_type = _AllocNode<__node_alloc_type>;
819
820 __hashtable&
821 _M_conjure_hashtable()
822 { return *(static_cast<__hashtable*>(this)); }
823
824 template<typename _InputIterator, typename _NodeGetter>
825 void
826 _M_insert_range(_InputIterator __first, _InputIterator __last,
827 const _NodeGetter&, true_type);
828
829 template<typename _InputIterator, typename _NodeGetter>
830 void
831 _M_insert_range(_InputIterator __first, _InputIterator __last,
832 const _NodeGetter&, false_type);
833
834 public:
835 __ireturn_type
836 insert(const value_type& __v)
837 {
838 __hashtable& __h = _M_conjure_hashtable();
839 __node_gen_type __node_gen(__h);
840 return __h._M_insert(__v, __node_gen, __unique_keys());
841 }
842
843 iterator
844 insert(const_iterator __hint, const value_type& __v)
845 {
846 __hashtable& __h = _M_conjure_hashtable();
847 __node_gen_type __node_gen(__h);
848 return __h._M_insert(__hint, __v, __node_gen, __unique_keys());
849 }
850
851 void
852 insert(initializer_list<value_type> __l)
853 { this->insert(__l.begin(), __l.end()); }
854
855 template<typename _InputIterator>
856 void
857 insert(_InputIterator __first, _InputIterator __last)
858 {
859 __hashtable& __h = _M_conjure_hashtable();
860 __node_gen_type __node_gen(__h);
861 return _M_insert_range(__first, __last, __node_gen, __unique_keys());
862 }
863 };
864
865 template<typename _Key, typename _Value, typename _Alloc,
866 typename _ExtractKey, typename _Equal,
867 typename _H1, typename _H2, typename _Hash,
868 typename _RehashPolicy, typename _Traits>
869 template<typename _InputIterator, typename _NodeGetter>
870 void
871 _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
872 _RehashPolicy, _Traits>::
873 _M_insert_range(_InputIterator __first, _InputIterator __last,
874 const _NodeGetter& __node_gen, true_type)
875 {
876 size_type __n_elt = __detail::__distance_fw(__first, __last);
877 if (__n_elt == 0)
878 return;
879
880 __hashtable& __h = _M_conjure_hashtable();
881 for (; __first != __last; ++__first)
882 {
883 if (__h._M_insert(*__first, __node_gen, __unique_keys(),
884 __n_elt).second)
885 __n_elt = 1;
886 else if (__n_elt != 1)
887 --__n_elt;
888 }
889 }
890
891 template<typename _Key, typename _Value, typename _Alloc,
892 typename _ExtractKey, typename _Equal,
893 typename _H1, typename _H2, typename _Hash,
894 typename _RehashPolicy, typename _Traits>
895 template<typename _InputIterator, typename _NodeGetter>
896 void
897 _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
898 _RehashPolicy, _Traits>::
899 _M_insert_range(_InputIterator __first, _InputIterator __last,
900 const _NodeGetter& __node_gen, false_type)
901 {
902 using __rehash_type = typename __hashtable::__rehash_type;
903 using __rehash_state = typename __hashtable::__rehash_state;
904 using pair_type = std::pair<bool, std::size_t>;
905
906 size_type __n_elt = __detail::__distance_fw(__first, __last);
907 if (__n_elt == 0)
908 return;
909
910 __hashtable& __h = _M_conjure_hashtable();
911 __rehash_type& __rehash = __h._M_rehash_policy;
912 const __rehash_state& __saved_state = __rehash._M_state();
913 pair_type __do_rehash = __rehash._M_need_rehash(__h._M_bucket_count,
914 __h._M_element_count,
915 __n_elt);
916
917 if (__do_rehash.first)
918 __h._M_rehash(__do_rehash.second, __saved_state);
919
920 for (; __first != __last; ++__first)
921 __h._M_insert(*__first, __node_gen, __unique_keys());
922 }
923
924 /**
925 * Primary class template _Insert.
926 *
927 * Defines @c insert member functions that depend on _Hashtable policies,
928 * via partial specializations.
929 */
930 template<typename _Key, typename _Value, typename _Alloc,
931 typename _ExtractKey, typename _Equal,
932 typename _H1, typename _H2, typename _Hash,
933 typename _RehashPolicy, typename _Traits,
934 bool _Constant_iterators = _Traits::__constant_iterators::value>
935 struct _Insert;
936
937 /// Specialization.
938 template<typename _Key, typename _Value, typename _Alloc,
939 typename _ExtractKey, typename _Equal,
940 typename _H1, typename _H2, typename _Hash,
941 typename _RehashPolicy, typename _Traits>
942 struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
943 _RehashPolicy, _Traits, true>
944 : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
945 _H1, _H2, _Hash, _RehashPolicy, _Traits>
946 {
947 using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
948 _Equal, _H1, _H2, _Hash,
949 _RehashPolicy, _Traits>;
950
951 using __hashtable_base = _Hashtable_base<_Key, _Value, _ExtractKey,
952 _Equal, _H1, _H2, _Hash,
953 _Traits>;
954
955 using value_type = typename __base_type::value_type;
956 using iterator = typename __base_type::iterator;
957 using const_iterator = typename __base_type::const_iterator;
958
959 using __unique_keys = typename __base_type::__unique_keys;
960 using __ireturn_type = typename __hashtable_base::__ireturn_type;
961 using __hashtable = typename __base_type::__hashtable;
962 using __node_gen_type = typename __base_type::__node_gen_type;
963
964 using __base_type::insert;
965
966 __ireturn_type
967 insert(value_type&& __v)
968 {
969 __hashtable& __h = this->_M_conjure_hashtable();
970 __node_gen_type __node_gen(__h);
971 return __h._M_insert(std::move(__v), __node_gen, __unique_keys());
972 }
973
974 iterator
975 insert(const_iterator __hint, value_type&& __v)
976 {
977 __hashtable& __h = this->_M_conjure_hashtable();
978 __node_gen_type __node_gen(__h);
979 return __h._M_insert(__hint, std::move(__v), __node_gen,
980 __unique_keys());
981 }
982 };
983
984 /// Specialization.
985 template<typename _Key, typename _Value, typename _Alloc,
986 typename _ExtractKey, typename _Equal,
987 typename _H1, typename _H2, typename _Hash,
988 typename _RehashPolicy, typename _Traits>
989 struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal, _H1, _H2, _Hash,
990 _RehashPolicy, _Traits, false>
991 : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
992 _H1, _H2, _Hash, _RehashPolicy, _Traits>
993 {
994 using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
995 _Equal, _H1, _H2, _Hash,
996 _RehashPolicy, _Traits>;
997 using value_type = typename __base_type::value_type;
998 using iterator = typename __base_type::iterator;
999 using const_iterator = typename __base_type::const_iterator;
1000
1001 using __unique_keys = typename __base_type::__unique_keys;
1002 using __hashtable = typename __base_type::__hashtable;
1003 using __ireturn_type = typename __base_type::__ireturn_type;
1004
1005 using __base_type::insert;
1006
1007 template<typename _Pair>
1008 using __is_cons = std::is_constructible<value_type, _Pair&&>;
1009
1010 template<typename _Pair>
1011 using _IFcons = std::enable_if<__is_cons<_Pair>::value>;
1012
1013 template<typename _Pair>
1014 using _IFconsp = typename _IFcons<_Pair>::type;
1015
1016 template<typename _Pair, typename = _IFconsp<_Pair>>
1017 __ireturn_type
1018 insert(_Pair&& __v)
1019 {
1020 __hashtable& __h = this->_M_conjure_hashtable();
1021 return __h._M_emplace(__unique_keys(), std::forward<_Pair>(__v));
1022 }
1023
1024 template<typename _Pair, typename = _IFconsp<_Pair>>
1025 iterator
1026 insert(const_iterator __hint, _Pair&& __v)
1027 {
1028 __hashtable& __h = this->_M_conjure_hashtable();
1029 return __h._M_emplace(__hint, __unique_keys(),
1030 std::forward<_Pair>(__v));
1031 }
1032 };
1033
1034 template<typename _Policy>
1035 using __has_load_factor = typename _Policy::__has_load_factor;
1036
1037 /**
1038 * Primary class template _Rehash_base.
1039 *
1040 * Give hashtable the max_load_factor functions and reserve iff the
1041 * rehash policy supports it.
1042 */
1043 template<typename _Key, typename _Value, typename _Alloc,
1044 typename _ExtractKey, typename _Equal,
1045 typename _H1, typename _H2, typename _Hash,
1046 typename _RehashPolicy, typename _Traits,
1047 typename =
1048 __detected_or_t<false_type, __has_load_factor, _RehashPolicy>>
1049 struct _Rehash_base;
1050
1051 /// Specialization when rehash policy doesn't provide load factor management.
1052 template<typename _Key, typename _Value, typename _Alloc,
1053 typename _ExtractKey, typename _Equal,
1054 typename _H1, typename _H2, typename _Hash,
1055 typename _RehashPolicy, typename _Traits>
1056 struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1057 _H1, _H2, _Hash, _RehashPolicy, _Traits,
1058 false_type>
1059 {
1060 };
1061
1062 /// Specialization when rehash policy provide load factor management.
1063 template<typename _Key, typename _Value, typename _Alloc,
1064 typename _ExtractKey, typename _Equal,
1065 typename _H1, typename _H2, typename _Hash,
1066 typename _RehashPolicy, typename _Traits>
1067 struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1068 _H1, _H2, _Hash, _RehashPolicy, _Traits,
1069 true_type>
1070 {
1071 using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
1072 _Equal, _H1, _H2, _Hash,
1073 _RehashPolicy, _Traits>;
1074
1075 float
1076 max_load_factor() const noexcept
1077 {
1078 const __hashtable* __this = static_cast<const __hashtable*>(this);
1079 return __this->__rehash_policy().max_load_factor();
1080 }
1081
1082 void
1083 max_load_factor(float __z)
1084 {
1085 __hashtable* __this = static_cast<__hashtable*>(this);
1086 __this->__rehash_policy(_RehashPolicy(__z));
1087 }
1088
1089 void
1090 reserve(std::size_t __n)
1091 {
1092 __hashtable* __this = static_cast<__hashtable*>(this);
1093 __this->rehash(__this->__rehash_policy()._M_bkt_for_elements(__n));
1094 }
1095 };
1096
1097 /**
1098 * Primary class template _Hashtable_ebo_helper.
1099 *
1100 * Helper class using EBO when it is not forbidden (the type is not
1101 * final) and when it is worth it (the type is empty.)
1102 */
1103 template<int _Nm, typename _Tp,
1104 bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
1105 struct _Hashtable_ebo_helper;
1106
1107 /// Specialization using EBO.
1108 template<int _Nm, typename _Tp>
1109 struct _Hashtable_ebo_helper<_Nm, _Tp, true>
1110 : private _Tp
1111 {
1112 _Hashtable_ebo_helper() noexcept(noexcept(_Tp())) : _Tp() { }
1113
1114 template<typename _OtherTp>
1115 _Hashtable_ebo_helper(_OtherTp&& __tp)
1116 : _Tp(std::forward<_OtherTp>(__tp))
1117 { }
1118
1119 const _Tp& _M_cget() const { return static_cast<const _Tp&>(*this); }
1120 _Tp& _M_get() { return static_cast<_Tp&>(*this); }
1121 };
1122
1123 /// Specialization not using EBO.
1124 template<int _Nm, typename _Tp>
1125 struct _Hashtable_ebo_helper<_Nm, _Tp, false>
1126 {
1127 _Hashtable_ebo_helper() = default;
1128
1129 template<typename _OtherTp>
1130 _Hashtable_ebo_helper(_OtherTp&& __tp)
1131 : _M_tp(std::forward<_OtherTp>(__tp))
1132 { }
1133
1134 const _Tp& _M_cget() const { return _M_tp; }
1135 _Tp& _M_get() { return _M_tp; }
1136
1137 private:
1138 _Tp _M_tp{};
1139 };
1140
1141 /**
1142 * Primary class template _Local_iterator_base.
1143 *
1144 * Base class for local iterators, used to iterate within a bucket
1145 * but not between buckets.
1146 */
1147 template<typename _Key, typename _Value, typename _ExtractKey,
1148 typename _H1, typename _H2, typename _Hash,
1149 bool __cache_hash_code>
1150 struct _Local_iterator_base;
1151
1152 /**
1153 * Primary class template _Hash_code_base.
1154 *
1155 * Encapsulates two policy issues that aren't quite orthogonal.
1156 * (1) the difference between using a ranged hash function and using
1157 * the combination of a hash function and a range-hashing function.
1158 * In the former case we don't have such things as hash codes, so
1159 * we have a dummy type as placeholder.
1160 * (2) Whether or not we cache hash codes. Caching hash codes is
1161 * meaningless if we have a ranged hash function.
1162 *
1163 * We also put the key extraction objects here, for convenience.
1164 * Each specialization derives from one or more of the template
1165 * parameters to benefit from Ebo. This is important as this type
1166 * is inherited in some cases by the _Local_iterator_base type used
1167 * to implement local_iterator and const_local_iterator. As with
1168 * any iterator type we prefer to make it as small as possible.
1169 *
1170 * Primary template is unused except as a hook for specializations.
1171 */
1172 template<typename _Key, typename _Value, typename _ExtractKey,
1173 typename _H1, typename _H2, typename _Hash,
1174 bool __cache_hash_code>
1175 struct _Hash_code_base;
1176
1177 /// Specialization: ranged hash function, no caching hash codes. H1
1178 /// and H2 are provided but ignored. We define a dummy hash code type.
1179 template<typename _Key, typename _Value, typename _ExtractKey,
1180 typename _H1, typename _H2, typename _Hash>
1181 struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash, false>
1182 : private _Hashtable_ebo_helper<0, _ExtractKey>,
1183 private _Hashtable_ebo_helper<1, _Hash>
1184 {
1185 private:
1186 using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;
1187 using __ebo_hash = _Hashtable_ebo_helper<1, _Hash>;
1188
1189 protected:
1190 typedef void* __hash_code;
1191 typedef _Hash_node<_Value, false> __node_type;
1192
1193 // We need the default constructor for the local iterators and _Hashtable
1194 // default constructor.
1195 _Hash_code_base() = default;
1196
1197 _Hash_code_base(const _ExtractKey& __ex, const _H1&, const _H2&,
1198 const _Hash& __h)
1199 : __ebo_extract_key(__ex), __ebo_hash(__h) { }
1200
1201 __hash_code
1202 _M_hash_code(const _Key& __key) const
1203 { return 0; }
1204
1205 std::size_t
1206 _M_bucket_index(const _Key& __k, __hash_code,
1207 std::size_t __bkt_count) const
1208 { return _M_ranged_hash()(__k, __bkt_count); }
1209
1210 std::size_t
1211 _M_bucket_index(const __node_type* __p, std::size_t __bkt_count) const
1212 noexcept( noexcept(declval<const _Hash&>()(declval<const _Key&>(),
1213 (std::size_t)0)) )
1214 { return _M_ranged_hash()(_M_extract()(__p->_M_v()), __bkt_count); }
1215
1216 void
1217 _M_store_code(__node_type*, __hash_code) const
1218 { }
1219
1220 void
1221 _M_copy_code(__node_type*, const __node_type*) const
1222 { }
1223
1224 void
1225 _M_swap(_Hash_code_base& __x)
1226 {
1227 std::swap(__ebo_extract_key::_M_get(),
1228 __x.__ebo_extract_key::_M_get());
1229 std::swap(__ebo_hash::_M_get(), __x.__ebo_hash::_M_get());
1230 }
1231
1232 const _ExtractKey&
1233 _M_extract() const { return __ebo_extract_key::_M_cget(); }
1234
1235 const _Hash&
1236 _M_ranged_hash() const { return __ebo_hash::_M_cget(); }
1237 };
1238
1239 // No specialization for ranged hash function while caching hash codes.
1240 // That combination is meaningless, and trying to do it is an error.
1241
1242 /// Specialization: ranged hash function, cache hash codes. This
1243 /// combination is meaningless, so we provide only a declaration
1244 /// and no definition.
1245 template<typename _Key, typename _Value, typename _ExtractKey,
1246 typename _H1, typename _H2, typename _Hash>
1247 struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash, true>;
1248
1249 /// Specialization: hash function and range-hashing function, no
1250 /// caching of hash codes.
1251 /// Provides typedef and accessor required by C++ 11.
1252 template<typename _Key, typename _Value, typename _ExtractKey,
1253 typename _H1, typename _H2>
1254 struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2,
1255 _Default_ranged_hash, false>
1256 : private _Hashtable_ebo_helper<0, _ExtractKey>,
1257 private _Hashtable_ebo_helper<1, _H1>,
1258 private _Hashtable_ebo_helper<2, _H2>
1259 {
1260 private:
1261 using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;
1262 using __ebo_h1 = _Hashtable_ebo_helper<1, _H1>;
1263 using __ebo_h2 = _Hashtable_ebo_helper<2, _H2>;
1264
1265 // Gives the local iterator implementation access to _M_bucket_index().
1266 friend struct _Local_iterator_base<_Key, _Value, _ExtractKey, _H1, _H2,
1267 _Default_ranged_hash, false>;
1268
1269 public:
1270 typedef _H1 hasher;
1271
1272 hasher
1273 hash_function() const
1274 { return _M_h1(); }
1275
1276 protected:
1277 typedef std::size_t __hash_code;
1278 typedef _Hash_node<_Value, false> __node_type;
1279
1280 // We need the default constructor for the local iterators and _Hashtable
1281 // default constructor.
1282 _Hash_code_base() = default;
1283
1284 _Hash_code_base(const _ExtractKey& __ex,
1285 const _H1& __h1, const _H2& __h2,
1286 const _Default_ranged_hash&)
1287 : __ebo_extract_key(__ex), __ebo_h1(__h1), __ebo_h2(__h2) { }
1288
1289 __hash_code
1290 _M_hash_code(const _Key& __k) const
1291 {
1292 static_assert(__is_invocable<const _H1&, const _Key&>{},
1293 "hash function must be invocable with an argument of key type");
1294 return _M_h1()(__k);
1295 }
1296
1297 std::size_t
1298 _M_bucket_index(const _Key&, __hash_code __c,
1299 std::size_t __bkt_count) const
1300 { return _M_h2()(__c, __bkt_count); }
1301
1302 std::size_t
1303 _M_bucket_index(const __node_type* __p, std::size_t __bkt_count) const
1304 noexcept( noexcept(declval<const _H1&>()(declval<const _Key&>()))
1305 && noexcept(declval<const _H2&>()((__hash_code)0,
1306 (std::size_t)0)) )
1307 { return _M_h2()(_M_h1()(_M_extract()(__p->_M_v())), __bkt_count); }
1308
1309 void
1310 _M_store_code(__node_type*, __hash_code) const
1311 { }
1312
1313 void
1314 _M_copy_code(__node_type*, const __node_type*) const
1315 { }
1316
1317 void
1318 _M_swap(_Hash_code_base& __x)
1319 {
1320 std::swap(__ebo_extract_key::_M_get(),
1321 __x.__ebo_extract_key::_M_get());
1322 std::swap(__ebo_h1::_M_get(), __x.__ebo_h1::_M_get());
1323 std::swap(__ebo_h2::_M_get(), __x.__ebo_h2::_M_get());
1324 }
1325
1326 const _ExtractKey&
1327 _M_extract() const { return __ebo_extract_key::_M_cget(); }
1328
1329 const _H1&
1330 _M_h1() const { return __ebo_h1::_M_cget(); }
1331
1332 const _H2&
1333 _M_h2() const { return __ebo_h2::_M_cget(); }
1334 };
1335
1336 /// Specialization: hash function and range-hashing function,
1337 /// caching hash codes. H is provided but ignored. Provides
1338 /// typedef and accessor required by C++ 11.
1339 template<typename _Key, typename _Value, typename _ExtractKey,
1340 typename _H1, typename _H2>
1341 struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2,
1342 _Default_ranged_hash, true>
1343 : private _Hashtable_ebo_helper<0, _ExtractKey>,
1344 private _Hashtable_ebo_helper<1, _H1>,
1345 private _Hashtable_ebo_helper<2, _H2>
1346 {
1347 private:
1348 // Gives the local iterator implementation access to _M_h2().
1349 friend struct _Local_iterator_base<_Key, _Value, _ExtractKey, _H1, _H2,
1350 _Default_ranged_hash, true>;
1351
1352 using __ebo_extract_key = _Hashtable_ebo_helper<0, _ExtractKey>;
1353 using __ebo_h1 = _Hashtable_ebo_helper<1, _H1>;
1354 using __ebo_h2 = _Hashtable_ebo_helper<2, _H2>;
1355
1356 public:
1357 typedef _H1 hasher;
1358
1359 hasher
1360 hash_function() const
1361 { return _M_h1(); }
1362
1363 protected:
1364 typedef std::size_t __hash_code;
1365 typedef _Hash_node<_Value, true> __node_type;
1366
1367 // We need the default constructor for _Hashtable default constructor.
1368 _Hash_code_base() = default;
1369 _Hash_code_base(const _ExtractKey& __ex,
1370 const _H1& __h1, const _H2& __h2,
1371 const _Default_ranged_hash&)
1372 : __ebo_extract_key(__ex), __ebo_h1(__h1), __ebo_h2(__h2) { }
1373
1374 __hash_code
1375 _M_hash_code(const _Key& __k) const
1376 {
1377 static_assert(__is_invocable<const _H1&, const _Key&>{},
1378 "hash function must be invocable with an argument of key type");
1379 return _M_h1()(__k);
1380 }
1381
1382 std::size_t
1383 _M_bucket_index(const _Key&, __hash_code __c,
1384 std::size_t __bkt_count) const
1385 { return _M_h2()(__c, __bkt_count); }
1386
1387 std::size_t
1388 _M_bucket_index(const __node_type* __p, std::size_t __bkt_count) const
1389 noexcept( noexcept(declval<const _H2&>()((__hash_code)0,
1390 (std::size_t)0)) )
1391 { return _M_h2()(__p->_M_hash_code, __bkt_count); }
1392
1393 void
1394 _M_store_code(__node_type* __n, __hash_code __c) const
1395 { __n->_M_hash_code = __c; }
1396
1397 void
1398 _M_copy_code(__node_type* __to, const __node_type* __from) const
1399 { __to->_M_hash_code = __from->_M_hash_code; }
1400
1401 void
1402 _M_swap(_Hash_code_base& __x)
1403 {
1404 std::swap(__ebo_extract_key::_M_get(),
1405 __x.__ebo_extract_key::_M_get());
1406 std::swap(__ebo_h1::_M_get(), __x.__ebo_h1::_M_get());
1407 std::swap(__ebo_h2::_M_get(), __x.__ebo_h2::_M_get());
1408 }
1409
1410 const _ExtractKey&
1411 _M_extract() const { return __ebo_extract_key::_M_cget(); }
1412
1413 const _H1&
1414 _M_h1() const { return __ebo_h1::_M_cget(); }
1415
1416 const _H2&
1417 _M_h2() const { return __ebo_h2::_M_cget(); }
1418 };
1419
1420 /// Partial specialization used when nodes contain a cached hash code.
1421 template<typename _Key, typename _Value, typename _ExtractKey,
1422 typename _H1, typename _H2, typename _Hash>
1423 struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1424 _H1, _H2, _Hash, true>
1425 : private _Hashtable_ebo_helper<0, _H2>
1426 {
1427 protected:
1428 using __base_type = _Hashtable_ebo_helper<0, _H2>;
1429 using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1430 _H1, _H2, _Hash, true>;
1431
1432 _Local_iterator_base() = default;
1433 _Local_iterator_base(const __hash_code_base& __base,
1434 _Hash_node<_Value, true>* __p,
1435 std::size_t __bkt, std::size_t __bkt_count)
1436 : __base_type(__base._M_h2()),
1437 _M_cur(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count) { }
1438
1439 void
1440 _M_incr()
1441 {
1442 _M_cur = _M_cur->_M_next();
1443 if (_M_cur)
1444 {
1445 std::size_t __bkt
1446 = __base_type::_M_get()(_M_cur->_M_hash_code,
1447 _M_bucket_count);
1448 if (__bkt != _M_bucket)
1449 _M_cur = nullptr;
1450 }
1451 }
1452
1453 _Hash_node<_Value, true>* _M_cur;
1454 std::size_t _M_bucket;
1455 std::size_t _M_bucket_count;
1456
1457 public:
1458 const void*
1459 _M_curr() const { return _M_cur; } // for equality ops
1460
1461 std::size_t
1462 _M_get_bucket() const { return _M_bucket; } // for debug mode
1463 };
1464
1465 // Uninitialized storage for a _Hash_code_base.
1466 // This type is DefaultConstructible and Assignable even if the
1467 // _Hash_code_base type isn't, so that _Local_iterator_base<..., false>
1468 // can be DefaultConstructible and Assignable.
1469 template<typename _Tp, bool _IsEmpty = std::is_empty<_Tp>::value>
1470 struct _Hash_code_storage
1471 {
1472 __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
1473
1474 _Tp*
1475 _M_h() { return _M_storage._M_ptr(); }
1476
1477 const _Tp*
1478 _M_h() const { return _M_storage._M_ptr(); }
1479 };
1480
1481 // Empty partial specialization for empty _Hash_code_base types.
1482 template<typename _Tp>
1483 struct _Hash_code_storage<_Tp, true>
1484 {
1485 static_assert( std::is_empty<_Tp>::value, "Type must be empty" );
1486
1487 // As _Tp is an empty type there will be no bytes written/read through
1488 // the cast pointer, so no strict-aliasing violation.
1489 _Tp*
1490 _M_h() { return reinterpret_cast<_Tp*>(this); }
1491
1492 const _Tp*
1493 _M_h() const { return reinterpret_cast<const _Tp*>(this); }
1494 };
1495
1496 template<typename _Key, typename _Value, typename _ExtractKey,
1497 typename _H1, typename _H2, typename _Hash>
1498 using __hash_code_for_local_iter
1499 = _Hash_code_storage<_Hash_code_base<_Key, _Value, _ExtractKey,
1500 _H1, _H2, _Hash, false>>;
1501
1502 // Partial specialization used when hash codes are not cached
1503 template<typename _Key, typename _Value, typename _ExtractKey,
1504 typename _H1, typename _H2, typename _Hash>
1505 struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1506 _H1, _H2, _Hash, false>
1507 : __hash_code_for_local_iter<_Key, _Value, _ExtractKey, _H1, _H2, _Hash>
1508 {
1509 protected:
1510 using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1511 _H1, _H2, _Hash, false>;
1512
1513 _Local_iterator_base() : _M_bucket_count(-1) { }
1514
1515 _Local_iterator_base(const __hash_code_base& __base,
1516 _Hash_node<_Value, false>* __p,
1517 std::size_t __bkt, std::size_t __bkt_count)
1518 : _M_cur(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
1519 { _M_init(__base); }
1520
1521 ~_Local_iterator_base()
1522 {
1523 if (_M_bucket_count != -1)
1524 _M_destroy();
1525 }
1526
1527 _Local_iterator_base(const _Local_iterator_base& __iter)
1528 : _M_cur(__iter._M_cur), _M_bucket(__iter._M_bucket),
1529 _M_bucket_count(__iter._M_bucket_count)
1530 {
1531 if (_M_bucket_count != -1)
1532 _M_init(*__iter._M_h());
1533 }
1534
1535 _Local_iterator_base&
1536 operator=(const _Local_iterator_base& __iter)
1537 {
1538 if (_M_bucket_count != -1)
1539 _M_destroy();
1540 _M_cur = __iter._M_cur;
1541 _M_bucket = __iter._M_bucket;
1542 _M_bucket_count = __iter._M_bucket_count;
1543 if (_M_bucket_count != -1)
1544 _M_init(*__iter._M_h());
1545 return *this;
1546 }
1547
1548 void
1549 _M_incr()
1550 {
1551 _M_cur = _M_cur->_M_next();
1552 if (_M_cur)
1553 {
1554 std::size_t __bkt = this->_M_h()->_M_bucket_index(_M_cur,
1555 _M_bucket_count);
1556 if (__bkt != _M_bucket)
1557 _M_cur = nullptr;
1558 }
1559 }
1560
1561 _Hash_node<_Value, false>* _M_cur;
1562 std::size_t _M_bucket;
1563 std::size_t _M_bucket_count;
1564
1565 void
1566 _M_init(const __hash_code_base& __base)
1567 { ::new(this->_M_h()) __hash_code_base(__base); }
1568
1569 void
1570 _M_destroy() { this->_M_h()->~__hash_code_base(); }
1571
1572 public:
1573 const void*
1574 _M_curr() const { return _M_cur; } // for equality ops and debug mode
1575
1576 std::size_t
1577 _M_get_bucket() const { return _M_bucket; } // for debug mode
1578 };
1579
1580 template<typename _Key, typename _Value, typename _ExtractKey,
1581 typename _H1, typename _H2, typename _Hash, bool __cache>
1582 inline bool
1583 operator==(const _Local_iterator_base<_Key, _Value, _ExtractKey,
1584 _H1, _H2, _Hash, __cache>& __x,
1585 const _Local_iterator_base<_Key, _Value, _ExtractKey,
1586 _H1, _H2, _Hash, __cache>& __y)
1587 { return __x._M_curr() == __y._M_curr(); }
1588
1589 template<typename _Key, typename _Value, typename _ExtractKey,
1590 typename _H1, typename _H2, typename _Hash, bool __cache>
1591 inline bool
1592 operator!=(const _Local_iterator_base<_Key, _Value, _ExtractKey,
1593 _H1, _H2, _Hash, __cache>& __x,
1594 const _Local_iterator_base<_Key, _Value, _ExtractKey,
1595 _H1, _H2, _Hash, __cache>& __y)
1596 { return __x._M_curr() != __y._M_curr(); }
1597
1598 /// local iterators
1599 template<typename _Key, typename _Value, typename _ExtractKey,
1600 typename _H1, typename _H2, typename _Hash,
1601 bool __constant_iterators, bool __cache>
1602 struct _Local_iterator
1603 : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1604 _H1, _H2, _Hash, __cache>
1605 {
1606 private:
1607 using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1608 _H1, _H2, _Hash, __cache>;
1609 using __hash_code_base = typename __base_type::__hash_code_base;
1610 public:
1611 typedef _Value value_type;
1612 typedef typename std::conditional<__constant_iterators,
1613 const _Value*, _Value*>::type
1614 pointer;
1615 typedef typename std::conditional<__constant_iterators,
1616 const _Value&, _Value&>::type
1617 reference;
1618 typedef std::ptrdiff_t difference_type;
1619 typedef std::forward_iterator_tag iterator_category;
1620
1621 _Local_iterator() = default;
1622
1623 _Local_iterator(const __hash_code_base& __base,
1624 _Hash_node<_Value, __cache>* __n,
1625 std::size_t __bkt, std::size_t __bkt_count)
1626 : __base_type(__base, __n, __bkt, __bkt_count)
1627 { }
1628
1629 reference
1630 operator*() const
1631 { return this->_M_cur->_M_v(); }
1632
1633 pointer
1634 operator->() const
1635 { return this->_M_cur->_M_valptr(); }
1636
1637 _Local_iterator&
1638 operator++()
1639 {
1640 this->_M_incr();
1641 return *this;
1642 }
1643
1644 _Local_iterator
1645 operator++(int)
1646 {
1647 _Local_iterator __tmp(*this);
1648 this->_M_incr();
1649 return __tmp;
1650 }
1651 };
1652
1653 /// local const_iterators
1654 template<typename _Key, typename _Value, typename _ExtractKey,
1655 typename _H1, typename _H2, typename _Hash,
1656 bool __constant_iterators, bool __cache>
1657 struct _Local_const_iterator
1658 : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1659 _H1, _H2, _Hash, __cache>
1660 {
1661 private:
1662 using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1663 _H1, _H2, _Hash, __cache>;
1664 using __hash_code_base = typename __base_type::__hash_code_base;
1665
1666 public:
1667 typedef _Value value_type;
1668 typedef const _Value* pointer;
1669 typedef const _Value& reference;
1670 typedef std::ptrdiff_t difference_type;
1671 typedef std::forward_iterator_tag iterator_category;
1672
1673 _Local_const_iterator() = default;
1674
1675 _Local_const_iterator(const __hash_code_base& __base,
1676 _Hash_node<_Value, __cache>* __n,
1677 std::size_t __bkt, std::size_t __bkt_count)
1678 : __base_type(__base, __n, __bkt, __bkt_count)
1679 { }
1680
1681 _Local_const_iterator(const _Local_iterator<_Key, _Value, _ExtractKey,
1682 _H1, _H2, _Hash,
1683 __constant_iterators,
1684 __cache>& __x)
1685 : __base_type(__x)
1686 { }
1687
1688 reference
1689 operator*() const
1690 { return this->_M_cur->_M_v(); }
1691
1692 pointer
1693 operator->() const
1694 { return this->_M_cur->_M_valptr(); }
1695
1696 _Local_const_iterator&
1697 operator++()
1698 {
1699 this->_M_incr();
1700 return *this;
1701 }
1702
1703 _Local_const_iterator
1704 operator++(int)
1705 {
1706 _Local_const_iterator __tmp(*this);
1707 this->_M_incr();
1708 return __tmp;
1709 }
1710 };
1711
1712 /**
1713 * Primary class template _Hashtable_base.
1714 *
1715 * Helper class adding management of _Equal functor to
1716 * _Hash_code_base type.
1717 *
1718 * Base class templates are:
1719 * - __detail::_Hash_code_base
1720 * - __detail::_Hashtable_ebo_helper
1721 */
1722 template<typename _Key, typename _Value,
1723 typename _ExtractKey, typename _Equal,
1724 typename _H1, typename _H2, typename _Hash, typename _Traits>
1725 struct _Hashtable_base
1726 : public _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2, _Hash,
1727 _Traits::__hash_cached::value>,
1728 private _Hashtable_ebo_helper<0, _Equal>
1729 {
1730 public:
1731 typedef _Key key_type;
1732 typedef _Value value_type;
1733 typedef _Equal key_equal;
1734 typedef std::size_t size_type;
1735 typedef std::ptrdiff_t difference_type;
1736
1737 using __traits_type = _Traits;
1738 using __hash_cached = typename __traits_type::__hash_cached;
1739 using __constant_iterators = typename __traits_type::__constant_iterators;
1740 using __unique_keys = typename __traits_type::__unique_keys;
1741
1742 using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1743 _H1, _H2, _Hash,
1744 __hash_cached::value>;
1745
1746 using __hash_code = typename __hash_code_base::__hash_code;
1747 using __node_type = typename __hash_code_base::__node_type;
1748
1749 using iterator = __detail::_Node_iterator<value_type,
1750 __constant_iterators::value,
1751 __hash_cached::value>;
1752
1753 using const_iterator = __detail::_Node_const_iterator<value_type,
1754 __constant_iterators::value,
1755 __hash_cached::value>;
1756
1757 using local_iterator = __detail::_Local_iterator<key_type, value_type,
1758 _ExtractKey, _H1, _H2, _Hash,
1759 __constant_iterators::value,
1760 __hash_cached::value>;
1761
1762 using const_local_iterator = __detail::_Local_const_iterator<key_type,
1763 value_type,
1764 _ExtractKey, _H1, _H2, _Hash,
1765 __constant_iterators::value,
1766 __hash_cached::value>;
1767
1768 using __ireturn_type = typename std::conditional<__unique_keys::value,
1769 std::pair<iterator, bool>,
1770 iterator>::type;
1771 private:
1772 using _EqualEBO = _Hashtable_ebo_helper<0, _Equal>;
1773
1774 template<typename _NodeT>
1775 struct _Equal_hash_code
1776 {
1777 static bool
1778 _S_equals(__hash_code, const _NodeT&)
1779 { return true; }
1780 };
1781
1782 template<typename _Ptr2>
1783 struct _Equal_hash_code<_Hash_node<_Ptr2, true>>
1784 {
1785 static bool
1786 _S_equals(__hash_code __c, const _Hash_node<_Ptr2, true>& __n)
1787 { return __c == __n._M_hash_code; }
1788 };
1789
1790 protected:
1791 _Hashtable_base() = default;
1792
1793 _Hashtable_base(const _ExtractKey& __ex, const _H1& __h1, const _H2& __h2,
1794 const _Hash& __hash, const _Equal& __eq)
1795 : __hash_code_base(__ex, __h1, __h2, __hash), _EqualEBO(__eq)
1796 { }
1797
1798 bool
1799 _M_equals(const _Key& __k, __hash_code __c, __node_type* __n) const
1800 {
1801 static_assert(__is_invocable<const _Equal&, const _Key&, const _Key&>{},
1802 "key equality predicate must be invocable with two arguments of "
1803 "key type");
1804 return _Equal_hash_code<__node_type>::_S_equals(__c, *__n)
1805 && _M_eq()(__k, this->_M_extract()(__n->_M_v()));
1806 }
1807
1808 void
1809 _M_swap(_Hashtable_base& __x)
1810 {
1811 __hash_code_base::_M_swap(__x);
1812 std::swap(_EqualEBO::_M_get(), __x._EqualEBO::_M_get());
1813 }
1814
1815 const _Equal&
1816 _M_eq() const { return _EqualEBO::_M_cget(); }
1817 };
1818
1819 /**
1820 * Primary class template _Equality.
1821 *
1822 * This is for implementing equality comparison for unordered
1823 * containers, per N3068, by John Lakos and Pablo Halpern.
1824 * Algorithmically, we follow closely the reference implementations
1825 * therein.
1826 */
1827 template<typename _Key, typename _Value, typename _Alloc,
1828 typename _ExtractKey, typename _Equal,
1829 typename _H1, typename _H2, typename _Hash,
1830 typename _RehashPolicy, typename _Traits,
1831 bool _Unique_keys = _Traits::__unique_keys::value>
1832 struct _Equality;
1833
1834 /// unordered_map and unordered_set specializations.
1835 template<typename _Key, typename _Value, typename _Alloc,
1836 typename _ExtractKey, typename _Equal,
1837 typename _H1, typename _H2, typename _Hash,
1838 typename _RehashPolicy, typename _Traits>
1839 struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1840 _H1, _H2, _Hash, _RehashPolicy, _Traits, true>
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, true>::
1856 _M_equal(const __hashtable& __other) const
1857 {
1858 using __node_base = typename __hashtable::__node_base;
1859 using __node_type = typename __hashtable::__node_type;
1860 const __hashtable* __this = static_cast<const __hashtable*>(this);
1861 if (__this->size() != __other.size())
1862 return false;
1863
1864 for (auto __itx = __this->begin(); __itx != __this->end(); ++__itx)
1865 {
1866 std::size_t __ybkt = __other._M_bucket_index(__itx._M_cur);
1867 __node_base* __prev_n = __other._M_buckets[__ybkt];
1868 if (!__prev_n)
1869 return false;
1870
1871 for (__node_type* __n = static_cast<__node_type*>(__prev_n->_M_nxt);;
1872 __n = __n->_M_next())
1873 {
1874 if (__n->_M_v() == *__itx)
1875 break;
1876
1877 if (!__n->_M_nxt
1878 || __other._M_bucket_index(__n->_M_next()) != __ybkt)
1879 return false;
1880 }
1881 }
1882
1883 return true;
1884 }
1885
1886 /// unordered_multiset and unordered_multimap specializations.
1887 template<typename _Key, typename _Value, typename _Alloc,
1888 typename _ExtractKey, typename _Equal,
1889 typename _H1, typename _H2, typename _Hash,
1890 typename _RehashPolicy, typename _Traits>
1891 struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1892 _H1, _H2, _Hash, _RehashPolicy, _Traits, false>
1893 {
1894 using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1895 _H1, _H2, _Hash, _RehashPolicy, _Traits>;
1896
1897 bool
1898 _M_equal(const __hashtable&) const;
1899 };
1900
1901 template<typename _Key, typename _Value, typename _Alloc,
1902 typename _ExtractKey, typename _Equal,
1903 typename _H1, typename _H2, typename _Hash,
1904 typename _RehashPolicy, typename _Traits>
1905 bool
1906 _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1907 _H1, _H2, _Hash, _RehashPolicy, _Traits, false>::
1908 _M_equal(const __hashtable& __other) const
1909 {
1910 using __node_base = typename __hashtable::__node_base;
1911 using __node_type = typename __hashtable::__node_type;
1912 const __hashtable* __this = static_cast<const __hashtable*>(this);
1913 if (__this->size() != __other.size())
1914 return false;
1915
1916 for (auto __itx = __this->begin(); __itx != __this->end();)
1917 {
1918 std::size_t __x_count = 1;
1919 auto __itx_end = __itx;
1920 for (++__itx_end; __itx_end != __this->end()
1921 && __this->key_eq()(_ExtractKey()(*__itx),
1922 _ExtractKey()(*__itx_end));
1923 ++__itx_end)
1924 ++__x_count;
1925
1926 std::size_t __ybkt = __other._M_bucket_index(__itx._M_cur);
1927 __node_base* __y_prev_n = __other._M_buckets[__ybkt];
1928 if (!__y_prev_n)
1929 return false;
1930
1931 __node_type* __y_n = static_cast<__node_type*>(__y_prev_n->_M_nxt);
1932 for (;; __y_n = __y_n->_M_next())
1933 {
1934 if (__this->key_eq()(_ExtractKey()(__y_n->_M_v()),
1935 _ExtractKey()(*__itx)))
1936 break;
1937
1938 if (!__y_n->_M_nxt
1939 || __other._M_bucket_index(__y_n->_M_next()) != __ybkt)
1940 return false;
1941 }
1942
1943 typename __hashtable::const_iterator __ity(__y_n);
1944 for (auto __ity_end = __ity; __ity_end != __other.end(); ++__ity_end)
1945 if (--__x_count == 0)
1946 break;
1947
1948 if (__x_count != 0)
1949 return false;
1950
1951 if (!std::is_permutation(__itx, __itx_end, __ity))
1952 return false;
1953
1954 __itx = __itx_end;
1955 }
1956 return true;
1957 }
1958
1959 /**
1960 * This type deals with all allocation and keeps an allocator instance
1961 * through inheritance to benefit from EBO when possible.
1962 */
1963 template<typename _NodeAlloc>
1964 struct _Hashtable_alloc : private _Hashtable_ebo_helper<0, _NodeAlloc>
1965 {
1966 private:
1967 using __ebo_node_alloc = _Hashtable_ebo_helper<0, _NodeAlloc>;
1968 public:
1969 using __node_type = typename _NodeAlloc::value_type;
1970 using __node_alloc_type = _NodeAlloc;
1971 // Use __gnu_cxx to benefit from _S_always_equal and al.
1972 using __node_alloc_traits = __gnu_cxx::__alloc_traits<__node_alloc_type>;
1973
1974 using __value_alloc_traits = typename __node_alloc_traits::template
1975 rebind_traits<typename __node_type::value_type>;
1976
1977 using __node_base = __detail::_Hash_node_base;
1978 using __bucket_type = __node_base*;
1979 using __bucket_alloc_type =
1980 __alloc_rebind<__node_alloc_type, __bucket_type>;
1981 using __bucket_alloc_traits = std::allocator_traits<__bucket_alloc_type>;
1982
1983 _Hashtable_alloc() = default;
1984 _Hashtable_alloc(const _Hashtable_alloc&) = default;
1985 _Hashtable_alloc(_Hashtable_alloc&&) = default;
1986
1987 template<typename _Alloc>
1988 _Hashtable_alloc(_Alloc&& __a)
1989 : __ebo_node_alloc(std::forward<_Alloc>(__a))
1990 { }
1991
1992 __node_alloc_type&
1993 _M_node_allocator()
1994 { return __ebo_node_alloc::_M_get(); }
1995
1996 const __node_alloc_type&
1997 _M_node_allocator() const
1998 { return __ebo_node_alloc::_M_cget(); }
1999
2000 // Allocate a node and construct an element within it.
2001 template<typename... _Args>
2002 __node_type*
2003 _M_allocate_node(_Args&&... __args);
2004
2005 // Destroy the element within a node and deallocate the node.
2006 void
2007 _M_deallocate_node(__node_type* __n);
2008
2009 // Deallocate a node.
2010 void
2011 _M_deallocate_node_ptr(__node_type* __n);
2012
2013 // Deallocate the linked list of nodes pointed to by __n.
2014 // The elements within the nodes are destroyed.
2015 void
2016 _M_deallocate_nodes(__node_type* __n);
2017
2018 __bucket_type*
2019 _M_allocate_buckets(std::size_t __bkt_count);
2020
2021 void
2022 _M_deallocate_buckets(__bucket_type*, std::size_t __bkt_count);
2023 };
2024
2025 // Definitions of class template _Hashtable_alloc's out-of-line member
2026 // functions.
2027 template<typename _NodeAlloc>
2028 template<typename... _Args>
2029 auto
2030 _Hashtable_alloc<_NodeAlloc>::_M_allocate_node(_Args&&... __args)
2031 -> __node_type*
2032 {
2033 auto __nptr = __node_alloc_traits::allocate(_M_node_allocator(), 1);
2034 __node_type* __n = std::__to_address(__nptr);
2035 __try
2036 {
2037 ::new ((void*)__n) __node_type;
2038 __node_alloc_traits::construct(_M_node_allocator(),
2039 __n->_M_valptr(),
2040 std::forward<_Args>(__args)...);
2041 return __n;
2042 }
2043 __catch(...)
2044 {
2045 __node_alloc_traits::deallocate(_M_node_allocator(), __nptr, 1);
2046 __throw_exception_again;
2047 }
2048 }
2049
2050 template<typename _NodeAlloc>
2051 void
2052 _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node(__node_type* __n)
2053 {
2054 __node_alloc_traits::destroy(_M_node_allocator(), __n->_M_valptr());
2055 _M_deallocate_node_ptr(__n);
2056 }
2057
2058 template<typename _NodeAlloc>
2059 void
2060 _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node_ptr(__node_type* __n)
2061 {
2062 typedef typename __node_alloc_traits::pointer _Ptr;
2063 auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__n);
2064 __n->~__node_type();
2065 __node_alloc_traits::deallocate(_M_node_allocator(), __ptr, 1);
2066 }
2067
2068 template<typename _NodeAlloc>
2069 void
2070 _Hashtable_alloc<_NodeAlloc>::_M_deallocate_nodes(__node_type* __n)
2071 {
2072 while (__n)
2073 {
2074 __node_type* __tmp = __n;
2075 __n = __n->_M_next();
2076 _M_deallocate_node(__tmp);
2077 }
2078 }
2079
2080 template<typename _NodeAlloc>
2081 typename _Hashtable_alloc<_NodeAlloc>::__bucket_type*
2082 _Hashtable_alloc<_NodeAlloc>::_M_allocate_buckets(std::size_t __bkt_count)
2083 {
2084 __bucket_alloc_type __alloc(_M_node_allocator());
2085
2086 auto __ptr = __bucket_alloc_traits::allocate(__alloc, __bkt_count);
2087 __bucket_type* __p = std::__to_address(__ptr);
2088 __builtin_memset(__p, 0, __bkt_count * sizeof(__bucket_type));
2089 return __p;
2090 }
2091
2092 template<typename _NodeAlloc>
2093 void
2094 _Hashtable_alloc<_NodeAlloc>::_M_deallocate_buckets(__bucket_type* __bkts,
2095 std::size_t __bkt_count)
2096 {
2097 typedef typename __bucket_alloc_traits::pointer _Ptr;
2098 auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__bkts);
2099 __bucket_alloc_type __alloc(_M_node_allocator());
2100 __bucket_alloc_traits::deallocate(__alloc, __ptr, __bkt_count);
2101 }
2102
2103 ///@} hashtable-detail
2104 } // namespace __detail
2105 _GLIBCXX_END_NAMESPACE_VERSION
2106 } // namespace std
2107
2108 #endif // _HASHTABLE_POLICY_H
2109