1// Internal policy header for unordered_set and unordered_map -*- C++ -*-
2
3// Copyright (C) 2010-2022 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file bits/hashtable_policy.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly.
28 * @headername{unordered_map,unordered_set}
29 */
30
31#ifndef _HASHTABLE_POLICY_H
32#define _HASHTABLE_POLICY_H 1
33
34#include <tuple> // for std::tuple, std::forward_as_tuple
35#include <bits/stl_algobase.h> // for std::min, std::is_permutation.
36#include <ext/aligned_buffer.h> // for __gnu_cxx::__aligned_buffer
37#include <ext/alloc_traits.h> // for std::__alloc_rebind
38#include <ext/numeric_traits.h> // for __gnu_cxx::__int_traits
39
40namespace std _GLIBCXX_VISIBILITY(default)
41{
42_GLIBCXX_BEGIN_NAMESPACE_VERSION
43/// @cond undocumented
44
45 template<typename _Key, typename _Value, typename _Alloc,
46 typename _ExtractKey, typename _Equal,
47 typename _Hash, typename _RangeHash, typename _Unused,
48 typename _RehashPolicy, typename _Traits>
49 class _Hashtable;
50
51namespace __detail
52{
53 /**
54 * @defgroup hashtable-detail Base and Implementation Classes
55 * @ingroup unordered_associative_containers
56 * @{
57 */
58 template<typename _Key, typename _Value, typename _ExtractKey,
59 typename _Equal, typename _Hash, typename _RangeHash,
60 typename _Unused, typename _Traits>
61 struct _Hashtable_base;
62
63 // Helper function: return distance(first, last) for forward
64 // iterators, or 0/1 for input iterators.
65 template<typename _Iterator>
66 inline typename std::iterator_traits<_Iterator>::difference_type
67 __distance_fw(_Iterator __first, _Iterator __last,
68 std::input_iterator_tag)
69 { return __first != __last ? 1 : 0; }
70
71 template<typename _Iterator>
72 inline typename std::iterator_traits<_Iterator>::difference_type
73 __distance_fw(_Iterator __first, _Iterator __last,
74 std::forward_iterator_tag)
75 { return std::distance(__first, __last); }
76
77 template<typename _Iterator>
78 inline typename std::iterator_traits<_Iterator>::difference_type
79 __distance_fw(_Iterator __first, _Iterator __last)
80 { return __distance_fw(__first, __last,
81 std::__iterator_category(__first)); }
82
83 struct _Identity
84 {
85 template<typename _Tp>
86 _Tp&&
87 operator()(_Tp&& __x) const noexcept
88 { return std::forward<_Tp>(__x); }
89 };
90
91 struct _Select1st
92 {
93 template<typename _Pair>
94 struct __1st_type;
95
96 template<typename _Tp, typename _Up>
97 struct __1st_type<pair<_Tp, _Up>>
98 { using type = _Tp; };
99
100 template<typename _Tp, typename _Up>
101 struct __1st_type<const pair<_Tp, _Up>>
102 { using type = const _Tp; };
103
104 template<typename _Pair>
105 struct __1st_type<_Pair&>
106 { using type = typename __1st_type<_Pair>::type&; };
107
108 template<typename _Tp>
109 typename __1st_type<_Tp>::type&&
110 operator()(_Tp&& __x) const noexcept
111 { return std::forward<_Tp>(__x).first; }
112 };
113
114 template<typename _ExKey>
115 struct _NodeBuilder;
116
117 template<>
118 struct _NodeBuilder<_Select1st>
119 {
120 template<typename _Kt, typename _Arg, typename _NodeGenerator>
121 static auto
122 _S_build(_Kt&& __k, _Arg&& __arg, const _NodeGenerator& __node_gen)
123 -> typename _NodeGenerator::__node_type*
124 {
125 return __node_gen(std::forward<_Kt>(__k),
126 std::forward<_Arg>(__arg).second);
127 }
128 };
129
130 template<>
131 struct _NodeBuilder<_Identity>
132 {
133 template<typename _Kt, typename _Arg, typename _NodeGenerator>
134 static auto
135 _S_build(_Kt&& __k, _Arg&&, const _NodeGenerator& __node_gen)
136 -> typename _NodeGenerator::__node_type*
137 { return __node_gen(std::forward<_Kt>(__k)); }
138 };
139
140 template<typename _NodeAlloc>
141 struct _Hashtable_alloc;
142
143 // Functor recycling a pool of nodes and using allocation once the pool is
144 // empty.
145 template<typename _NodeAlloc>
146 struct _ReuseOrAllocNode
147 {
148 private:
149 using __node_alloc_type = _NodeAlloc;
150 using __hashtable_alloc = _Hashtable_alloc<__node_alloc_type>;
151 using __node_alloc_traits =
152 typename __hashtable_alloc::__node_alloc_traits;
153
154 public:
155 using __node_type = typename __hashtable_alloc::__node_type;
156
157 _ReuseOrAllocNode(__node_type* __nodes, __hashtable_alloc& __h)
158 : _M_nodes(__nodes), _M_h(__h) { }
159 _ReuseOrAllocNode(const _ReuseOrAllocNode&) = delete;
160
161 ~_ReuseOrAllocNode()
162 { _M_h._M_deallocate_nodes(_M_nodes); }
163
164 template<typename... _Args>
165 __node_type*
166 operator()(_Args&&... __args) const
167 {
168 if (_M_nodes)
169 {
170 __node_type* __node = _M_nodes;
171 _M_nodes = _M_nodes->_M_next();
172 __node->_M_nxt = nullptr;
173 auto& __a = _M_h._M_node_allocator();
174 __node_alloc_traits::destroy(__a, __node->_M_valptr());
175 __try
176 {
177 __node_alloc_traits::construct(__a, __node->_M_valptr(),
178 std::forward<_Args>(__args)...);
179 }
180 __catch(...)
181 {
182 _M_h._M_deallocate_node_ptr(__node);
183 __throw_exception_again;
184 }
185 return __node;
186 }
187 return _M_h._M_allocate_node(std::forward<_Args>(__args)...);
188 }
189
190 private:
191 mutable __node_type* _M_nodes;
192 __hashtable_alloc& _M_h;
193 };
194
195 // Functor similar to the previous one but without any pool of nodes to
196 // recycle.
197 template<typename _NodeAlloc>
198 struct _AllocNode
199 {
200 private:
201 using __hashtable_alloc = _Hashtable_alloc<_NodeAlloc>;
202
203 public:
204 using __node_type = typename __hashtable_alloc::__node_type;
205
206 _AllocNode(__hashtable_alloc& __h)
207 : _M_h(__h) { }
208
209 template<typename... _Args>
210 __node_type*
211 operator()(_Args&&... __args) const
212 { return _M_h._M_allocate_node(std::forward<_Args>(__args)...); }
213
214 private:
215 __hashtable_alloc& _M_h;
216 };
217
218 // Auxiliary types used for all instantiations of _Hashtable nodes
219 // and iterators.
220
221 /**
222 * struct _Hashtable_traits
223 *
224 * Important traits for hash tables.
225 *
226 * @tparam _Cache_hash_code Boolean value. True if the value of
227 * the hash function is stored along with the value. This is a
228 * time-space tradeoff. Storing it may improve lookup speed by
229 * reducing the number of times we need to call the _Hash or _Equal
230 * functors.
231 *
232 * @tparam _Constant_iterators Boolean value. True if iterator and
233 * const_iterator are both constant iterator types. This is true
234 * for unordered_set and unordered_multiset, false for
235 * unordered_map and unordered_multimap.
236 *
237 * @tparam _Unique_keys Boolean value. True if the return value
238 * of _Hashtable::count(k) is always at most one, false if it may
239 * be an arbitrary number. This is true for unordered_set and
240 * unordered_map, false for unordered_multiset and
241 * unordered_multimap.
242 */
243 template<bool _Cache_hash_code, bool _Constant_iterators, bool _Unique_keys>
244 struct _Hashtable_traits
245 {
246 using __hash_cached = __bool_constant<_Cache_hash_code>;
247 using __constant_iterators = __bool_constant<_Constant_iterators>;
248 using __unique_keys = __bool_constant<_Unique_keys>;
249 };
250
251 /**
252 * struct _Hashtable_hash_traits
253 *
254 * Important traits for hash tables depending on associated hasher.
255 *
256 */
257 template<typename _Hash>
258 struct _Hashtable_hash_traits
259 {
260 static constexpr std::size_t
261 __small_size_threshold() noexcept
262 { return std::__is_fast_hash<_Hash>::value ? 0 : 20; }
263 };
264
265 /**
266 * struct _Hash_node_base
267 *
268 * Nodes, used to wrap elements stored in the hash table. A policy
269 * template parameter of class template _Hashtable controls whether
270 * nodes also store a hash code. In some cases (e.g. strings) this
271 * may be a performance win.
272 */
273 struct _Hash_node_base
274 {
275 _Hash_node_base* _M_nxt;
276
277 _Hash_node_base() noexcept : _M_nxt() { }
278
279 _Hash_node_base(_Hash_node_base* __next) noexcept : _M_nxt(__next) { }
280 };
281
282 /**
283 * struct _Hash_node_value_base
284 *
285 * Node type with the value to store.
286 */
287 template<typename _Value>
288 struct _Hash_node_value_base
289 {
290 typedef _Value value_type;
291
292 __gnu_cxx::__aligned_buffer<_Value> _M_storage;
293
294 _Value*
295 _M_valptr() noexcept
296 { return _M_storage._M_ptr(); }
297
298 const _Value*
299 _M_valptr() const noexcept
300 { return _M_storage._M_ptr(); }
301
302 _Value&
303 _M_v() noexcept
304 { return *_M_valptr(); }
305
306 const _Value&
307 _M_v() const noexcept
308 { return *_M_valptr(); }
309 };
310
311 /**
312 * Primary template struct _Hash_node_code_cache.
313 */
314 template<bool _Cache_hash_code>
315 struct _Hash_node_code_cache
316 { };
317
318 /**
319 * Specialization for node with cache, struct _Hash_node_code_cache.
320 */
321 template<>
322 struct _Hash_node_code_cache<true>
323 { std::size_t _M_hash_code; };
324
325 template<typename _Value, bool _Cache_hash_code>
326 struct _Hash_node_value
327 : _Hash_node_value_base<_Value>
328 , _Hash_node_code_cache<_Cache_hash_code>
329 { };
330
331 /**
332 * Primary template struct _Hash_node.
333 */
334 template<typename _Value, bool _Cache_hash_code>
335 struct _Hash_node
336 : _Hash_node_base
337 , _Hash_node_value<_Value, _Cache_hash_code>
338 {
339 _Hash_node*
340 _M_next() const noexcept
341 { return static_cast<_Hash_node*>(this->_M_nxt); }
342 };
343
344 /// Base class for node iterators.
345 template<typename _Value, bool _Cache_hash_code>
346 struct _Node_iterator_base
347 {
348 using __node_type = _Hash_node<_Value, _Cache_hash_code>;
349
350 __node_type* _M_cur;
351
352 _Node_iterator_base() : _M_cur(nullptr) { }
353 _Node_iterator_base(__node_type* __p) noexcept
354 : _M_cur(__p) { }
355
356 void
357 _M_incr() noexcept
358 { _M_cur = _M_cur->_M_next(); }
359
360 friend bool
361 operator==(const _Node_iterator_base& __x, const _Node_iterator_base& __y)
362 noexcept
363 { return __x._M_cur == __y._M_cur; }
364
365#if __cpp_impl_three_way_comparison < 201907L
366 friend bool
367 operator!=(const _Node_iterator_base& __x, const _Node_iterator_base& __y)
368 noexcept
369 { return __x._M_cur != __y._M_cur; }
370#endif
371 };
372
373 /// Node iterators, used to iterate through all the hashtable.
374 template<typename _Value, bool __constant_iterators, bool __cache>
375 struct _Node_iterator
376 : public _Node_iterator_base<_Value, __cache>
377 {
378 private:
379 using __base_type = _Node_iterator_base<_Value, __cache>;
380 using __node_type = typename __base_type::__node_type;
381
382 public:
383 using value_type = _Value;
384 using difference_type = std::ptrdiff_t;
385 using iterator_category = std::forward_iterator_tag;
386
387 using pointer = __conditional_t<__constant_iterators,
388 const value_type*, value_type*>;
389
390 using reference = __conditional_t<__constant_iterators,
391 const value_type&, value_type&>;
392
393 _Node_iterator() = default;
394
395 explicit
396 _Node_iterator(__node_type* __p) noexcept
397 : __base_type(__p) { }
398
399 reference
400 operator*() const noexcept
401 { return this->_M_cur->_M_v(); }
402
403 pointer
404 operator->() const noexcept
405 { return this->_M_cur->_M_valptr(); }
406
407 _Node_iterator&
408 operator++() noexcept
409 {
410 this->_M_incr();
411 return *this;
412 }
413
414 _Node_iterator
415 operator++(int) noexcept
416 {
417 _Node_iterator __tmp(*this);
418 this->_M_incr();
419 return __tmp;
420 }
421 };
422
423 /// Node const_iterators, used to iterate through all the hashtable.
424 template<typename _Value, bool __constant_iterators, bool __cache>
425 struct _Node_const_iterator
426 : public _Node_iterator_base<_Value, __cache>
427 {
428 private:
429 using __base_type = _Node_iterator_base<_Value, __cache>;
430 using __node_type = typename __base_type::__node_type;
431
432 public:
433 typedef _Value value_type;
434 typedef std::ptrdiff_t difference_type;
435 typedef std::forward_iterator_tag iterator_category;
436
437 typedef const value_type* pointer;
438 typedef const value_type& reference;
439
440 _Node_const_iterator() = default;
441
442 explicit
443 _Node_const_iterator(__node_type* __p) noexcept
444 : __base_type(__p) { }
445
446 _Node_const_iterator(const _Node_iterator<_Value, __constant_iterators,
447 __cache>& __x) noexcept
448 : __base_type(__x._M_cur) { }
449
450 reference
451 operator*() const noexcept
452 { return this->_M_cur->_M_v(); }
453
454 pointer
455 operator->() const noexcept
456 { return this->_M_cur->_M_valptr(); }
457
458 _Node_const_iterator&
459 operator++() noexcept
460 {
461 this->_M_incr();
462 return *this;
463 }
464
465 _Node_const_iterator
466 operator++(int) noexcept
467 {
468 _Node_const_iterator __tmp(*this);
469 this->_M_incr();
470 return __tmp;
471 }
472 };
473
474 // Many of class template _Hashtable's template parameters are policy
475 // classes. These are defaults for the policies.
476
477 /// Default range hashing function: use division to fold a large number
478 /// into the range [0, N).
479 struct _Mod_range_hashing
480 {
481 typedef std::size_t first_argument_type;
482 typedef std::size_t second_argument_type;
483 typedef std::size_t result_type;
484
485 result_type
486 operator()(first_argument_type __num,
487 second_argument_type __den) const noexcept
488 { return __num % __den; }
489 };
490
491 /// Default ranged hash function H. In principle it should be a
492 /// function object composed from objects of type H1 and H2 such that
493 /// h(k, N) = h2(h1(k), N), but that would mean making extra copies of
494 /// h1 and h2. So instead we'll just use a tag to tell class template
495 /// hashtable to do that composition.
496 struct _Default_ranged_hash { };
497
498 /// Default value for rehash policy. Bucket size is (usually) the
499 /// smallest prime that keeps the load factor small enough.
500 struct _Prime_rehash_policy
501 {
502 using __has_load_factor = true_type;
503
504 _Prime_rehash_policy(float __z = 1.0) noexcept
505 : _M_max_load_factor(__z), _M_next_resize(0) { }
506
507 float
508 max_load_factor() const noexcept
509 { return _M_max_load_factor; }
510
511 // Return a bucket size no smaller than n.
512 std::size_t
513 _M_next_bkt(std::size_t __n) const;
514
515 // Return a bucket count appropriate for n elements
516 std::size_t
517 _M_bkt_for_elements(std::size_t __n) const
518 { return __builtin_ceil(__n / (double)_M_max_load_factor); }
519
520 // __n_bkt is current bucket count, __n_elt is current element count,
521 // and __n_ins is number of elements to be inserted. Do we need to
522 // increase bucket count? If so, return make_pair(true, n), where n
523 // is the new bucket count. If not, return make_pair(false, 0).
524 std::pair<bool, std::size_t>
525 _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
526 std::size_t __n_ins) const;
527
528 typedef std::size_t _State;
529
530 _State
531 _M_state() const
532 { return _M_next_resize; }
533
534 void
535 _M_reset() noexcept
536 { _M_next_resize = 0; }
537
538 void
539 _M_reset(_State __state)
540 { _M_next_resize = __state; }
541
542 static const std::size_t _S_growth_factor = 2;
543
544 float _M_max_load_factor;
545 mutable std::size_t _M_next_resize;
546 };
547
548 /// Range hashing function assuming that second arg is a power of 2.
549 struct _Mask_range_hashing
550 {
551 typedef std::size_t first_argument_type;
552 typedef std::size_t second_argument_type;
553 typedef std::size_t result_type;
554
555 result_type
556 operator()(first_argument_type __num,
557 second_argument_type __den) const noexcept
558 { return __num & (__den - 1); }
559 };
560
561 /// Compute closest power of 2 not less than __n
562 inline std::size_t
563 __clp2(std::size_t __n) noexcept
564 {
565 using __gnu_cxx::__int_traits;
566 // Equivalent to return __n ? std::bit_ceil(__n) : 0;
567 if (__n < 2)
568 return __n;
569 const unsigned __lz = sizeof(size_t) > sizeof(long)
570 ? __builtin_clzll(__n - 1ull)
571 : __builtin_clzl(__n - 1ul);
572 // Doing two shifts avoids undefined behaviour when __lz == 0.
573 return (size_t(1) << (__int_traits<size_t>::__digits - __lz - 1)) << 1;
574 }
575
576 /// Rehash policy providing power of 2 bucket numbers. Avoids modulo
577 /// operations.
578 struct _Power2_rehash_policy
579 {
580 using __has_load_factor = true_type;
581
582 _Power2_rehash_policy(float __z = 1.0) noexcept
583 : _M_max_load_factor(__z), _M_next_resize(0) { }
584
585 float
586 max_load_factor() const noexcept
587 { return _M_max_load_factor; }
588
589 // Return a bucket size no smaller than n (as long as n is not above the
590 // highest power of 2).
591 std::size_t
592 _M_next_bkt(std::size_t __n) noexcept
593 {
594 if (__n == 0)
595 // Special case on container 1st initialization with 0 bucket count
596 // hint. We keep _M_next_resize to 0 to make sure that next time we
597 // want to add an element allocation will take place.
598 return 1;
599
600 const auto __max_width = std::min<size_t>(a: sizeof(size_t), b: 8);
601 const auto __max_bkt = size_t(1) << (__max_width * __CHAR_BIT__ - 1);
602 std::size_t __res = __clp2(__n);
603
604 if (__res == 0)
605 __res = __max_bkt;
606 else if (__res == 1)
607 // If __res is 1 we force it to 2 to make sure there will be an
608 // allocation so that nothing need to be stored in the initial
609 // single bucket
610 __res = 2;
611
612 if (__res == __max_bkt)
613 // Set next resize to the max value so that we never try to rehash again
614 // as we already reach the biggest possible bucket number.
615 // Note that it might result in max_load_factor not being respected.
616 _M_next_resize = size_t(-1);
617 else
618 _M_next_resize
619 = __builtin_floor(__res * (double)_M_max_load_factor);
620
621 return __res;
622 }
623
624 // Return a bucket count appropriate for n elements
625 std::size_t
626 _M_bkt_for_elements(std::size_t __n) const noexcept
627 { return __builtin_ceil(__n / (double)_M_max_load_factor); }
628
629 // __n_bkt is current bucket count, __n_elt is current element count,
630 // and __n_ins is number of elements to be inserted. Do we need to
631 // increase bucket count? If so, return make_pair(true, n), where n
632 // is the new bucket count. If not, return make_pair(false, 0).
633 std::pair<bool, std::size_t>
634 _M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
635 std::size_t __n_ins) noexcept
636 {
637 if (__n_elt + __n_ins > _M_next_resize)
638 {
639 // If _M_next_resize is 0 it means that we have nothing allocated so
640 // far and that we start inserting elements. In this case we start
641 // with an initial bucket size of 11.
642 double __min_bkts
643 = std::max<std::size_t>(a: __n_elt + __n_ins, b: _M_next_resize ? 0 : 11)
644 / (double)_M_max_load_factor;
645 if (__min_bkts >= __n_bkt)
646 return { true,
647 _M_next_bkt(n: std::max<std::size_t>(a: __builtin_floor(__min_bkts) + 1,
648 b: __n_bkt * _S_growth_factor)) };
649
650 _M_next_resize
651 = __builtin_floor(__n_bkt * (double)_M_max_load_factor);
652 return { false, 0 };
653 }
654 else
655 return { false, 0 };
656 }
657
658 typedef std::size_t _State;
659
660 _State
661 _M_state() const noexcept
662 { return _M_next_resize; }
663
664 void
665 _M_reset() noexcept
666 { _M_next_resize = 0; }
667
668 void
669 _M_reset(_State __state) noexcept
670 { _M_next_resize = __state; }
671
672 static const std::size_t _S_growth_factor = 2;
673
674 float _M_max_load_factor;
675 std::size_t _M_next_resize;
676 };
677
678 // Base classes for std::_Hashtable. We define these base classes
679 // because in some cases we want to do different things depending on
680 // the value of a policy class. In some cases the policy class
681 // affects which member functions and nested typedefs are defined;
682 // we handle that by specializing base class templates. Several of
683 // the base class templates need to access other members of class
684 // template _Hashtable, so we use a variant of the "Curiously
685 // Recurring Template Pattern" (CRTP) technique.
686
687 /**
688 * Primary class template _Map_base.
689 *
690 * If the hashtable has a value type of the form pair<const T1, T2> and
691 * a key extraction policy (_ExtractKey) that returns the first part
692 * of the pair, the hashtable gets a mapped_type typedef. If it
693 * satisfies those criteria and also has unique keys, then it also
694 * gets an operator[].
695 */
696 template<typename _Key, typename _Value, typename _Alloc,
697 typename _ExtractKey, typename _Equal,
698 typename _Hash, typename _RangeHash, typename _Unused,
699 typename _RehashPolicy, typename _Traits,
700 bool _Unique_keys = _Traits::__unique_keys::value>
701 struct _Map_base { };
702
703 /// Partial specialization, __unique_keys set to false, std::pair value type.
704 template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
705 typename _Hash, typename _RangeHash, typename _Unused,
706 typename _RehashPolicy, typename _Traits>
707 struct _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
708 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
709 {
710 using mapped_type = _Val;
711 };
712
713 /// Partial specialization, __unique_keys set to true.
714 template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
715 typename _Hash, typename _RangeHash, typename _Unused,
716 typename _RehashPolicy, typename _Traits>
717 struct _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
718 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>
719 {
720 private:
721 using __hashtable_base = _Hashtable_base<_Key, pair<const _Key, _Val>,
722 _Select1st, _Equal, _Hash,
723 _RangeHash, _Unused,
724 _Traits>;
725
726 using __hashtable = _Hashtable<_Key, pair<const _Key, _Val>, _Alloc,
727 _Select1st, _Equal, _Hash, _RangeHash,
728 _Unused, _RehashPolicy, _Traits>;
729
730 using __hash_code = typename __hashtable_base::__hash_code;
731
732 public:
733 using key_type = typename __hashtable_base::key_type;
734 using mapped_type = _Val;
735
736 mapped_type&
737 operator[](const key_type& __k);
738
739 mapped_type&
740 operator[](key_type&& __k);
741
742 // _GLIBCXX_RESOLVE_LIB_DEFECTS
743 // DR 761. unordered_map needs an at() member function.
744 mapped_type&
745 at(const key_type& __k)
746 {
747 auto __ite = static_cast<__hashtable*>(this)->find(__k);
748 if (!__ite._M_cur)
749 __throw_out_of_range(__N("unordered_map::at"));
750 return __ite->second;
751 }
752
753 const mapped_type&
754 at(const key_type& __k) const
755 {
756 auto __ite = static_cast<const __hashtable*>(this)->find(__k);
757 if (!__ite._M_cur)
758 __throw_out_of_range(__N("unordered_map::at"));
759 return __ite->second;
760 }
761 };
762
763 template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
764 typename _Hash, typename _RangeHash, typename _Unused,
765 typename _RehashPolicy, typename _Traits>
766 auto
767 _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
768 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
769 operator[](const key_type& __k)
770 -> mapped_type&
771 {
772 __hashtable* __h = static_cast<__hashtable*>(this);
773 __hash_code __code = __h->_M_hash_code(__k);
774 std::size_t __bkt = __h->_M_bucket_index(__code);
775 if (auto __node = __h->_M_find_node(__bkt, __k, __code))
776 return __node->_M_v().second;
777
778 typename __hashtable::_Scoped_node __node {
779 __h,
780 std::piecewise_construct,
781 std::tuple<const key_type&>(__k),
782 std::tuple<>()
783 };
784 auto __pos
785 = __h->_M_insert_unique_node(__bkt, __code, __node._M_node);
786 __node._M_node = nullptr;
787 return __pos->second;
788 }
789
790 template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
791 typename _Hash, typename _RangeHash, typename _Unused,
792 typename _RehashPolicy, typename _Traits>
793 auto
794 _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal,
795 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
796 operator[](key_type&& __k)
797 -> mapped_type&
798 {
799 __hashtable* __h = static_cast<__hashtable*>(this);
800 __hash_code __code = __h->_M_hash_code(__k);
801 std::size_t __bkt = __h->_M_bucket_index(__code);
802 if (auto __node = __h->_M_find_node(__bkt, __k, __code))
803 return __node->_M_v().second;
804
805 typename __hashtable::_Scoped_node __node {
806 __h,
807 std::piecewise_construct,
808 std::forward_as_tuple(std::move(__k)),
809 std::tuple<>()
810 };
811 auto __pos
812 = __h->_M_insert_unique_node(__bkt, __code, __node._M_node);
813 __node._M_node = nullptr;
814 return __pos->second;
815 }
816
817 // Partial specialization for unordered_map<const T, U>, see PR 104174.
818 template<typename _Key, typename _Val, typename _Alloc, typename _Equal,
819 typename _Hash, typename _RangeHash, typename _Unused,
820 typename _RehashPolicy, typename _Traits, bool __uniq>
821 struct _Map_base<const _Key, pair<const _Key, _Val>,
822 _Alloc, _Select1st, _Equal, _Hash,
823 _RangeHash, _Unused, _RehashPolicy, _Traits, __uniq>
824 : _Map_base<_Key, pair<const _Key, _Val>, _Alloc, _Select1st, _Equal, _Hash,
825 _RangeHash, _Unused, _RehashPolicy, _Traits, __uniq>
826 { };
827
828 /**
829 * Primary class template _Insert_base.
830 *
831 * Defines @c insert member functions appropriate to all _Hashtables.
832 */
833 template<typename _Key, typename _Value, typename _Alloc,
834 typename _ExtractKey, typename _Equal,
835 typename _Hash, typename _RangeHash, typename _Unused,
836 typename _RehashPolicy, typename _Traits>
837 struct _Insert_base
838 {
839 protected:
840 using __hashtable_base = _Hashtable_base<_Key, _Value, _ExtractKey,
841 _Equal, _Hash, _RangeHash,
842 _Unused, _Traits>;
843
844 using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
845 _Hash, _RangeHash,
846 _Unused, _RehashPolicy, _Traits>;
847
848 using __hash_cached = typename _Traits::__hash_cached;
849 using __constant_iterators = typename _Traits::__constant_iterators;
850
851 using __hashtable_alloc = _Hashtable_alloc<
852 __alloc_rebind<_Alloc, _Hash_node<_Value,
853 __hash_cached::value>>>;
854
855 using value_type = typename __hashtable_base::value_type;
856 using size_type = typename __hashtable_base::size_type;
857
858 using __unique_keys = typename _Traits::__unique_keys;
859 using __node_alloc_type = typename __hashtable_alloc::__node_alloc_type;
860 using __node_gen_type = _AllocNode<__node_alloc_type>;
861
862 __hashtable&
863 _M_conjure_hashtable()
864 { return *(static_cast<__hashtable*>(this)); }
865
866 template<typename _InputIterator, typename _NodeGetter>
867 void
868 _M_insert_range(_InputIterator __first, _InputIterator __last,
869 const _NodeGetter&, true_type __uks);
870
871 template<typename _InputIterator, typename _NodeGetter>
872 void
873 _M_insert_range(_InputIterator __first, _InputIterator __last,
874 const _NodeGetter&, false_type __uks);
875
876 public:
877 using iterator = _Node_iterator<_Value, __constant_iterators::value,
878 __hash_cached::value>;
879
880 using const_iterator = _Node_const_iterator<_Value,
881 __constant_iterators::value,
882 __hash_cached::value>;
883
884 using __ireturn_type = __conditional_t<__unique_keys::value,
885 std::pair<iterator, bool>,
886 iterator>;
887
888 __ireturn_type
889 insert(const value_type& __v)
890 {
891 __hashtable& __h = _M_conjure_hashtable();
892 __node_gen_type __node_gen(__h);
893 return __h._M_insert(__v, __node_gen, __unique_keys{});
894 }
895
896 iterator
897 insert(const_iterator __hint, const value_type& __v)
898 {
899 __hashtable& __h = _M_conjure_hashtable();
900 __node_gen_type __node_gen(__h);
901 return __h._M_insert(__hint, __v, __node_gen, __unique_keys{});
902 }
903
904 template<typename _KType, typename... _Args>
905 std::pair<iterator, bool>
906 try_emplace(const_iterator, _KType&& __k, _Args&&... __args)
907 {
908 __hashtable& __h = _M_conjure_hashtable();
909 auto __code = __h._M_hash_code(__k);
910 std::size_t __bkt = __h._M_bucket_index(__code);
911 if (auto __node = __h._M_find_node(__bkt, __k, __code))
912 return { iterator(__node), false };
913
914 typename __hashtable::_Scoped_node __node {
915 &__h,
916 std::piecewise_construct,
917 std::forward_as_tuple(std::forward<_KType>(__k)),
918 std::forward_as_tuple(std::forward<_Args>(__args)...)
919 };
920 auto __it
921 = __h._M_insert_unique_node(__bkt, __code, __node._M_node);
922 __node._M_node = nullptr;
923 return { __it, true };
924 }
925
926 void
927 insert(initializer_list<value_type> __l)
928 { this->insert(__l.begin(), __l.end()); }
929
930 template<typename _InputIterator>
931 void
932 insert(_InputIterator __first, _InputIterator __last)
933 {
934 __hashtable& __h = _M_conjure_hashtable();
935 __node_gen_type __node_gen(__h);
936 return _M_insert_range(__first, __last, __node_gen, __unique_keys{});
937 }
938 };
939
940 template<typename _Key, typename _Value, typename _Alloc,
941 typename _ExtractKey, typename _Equal,
942 typename _Hash, typename _RangeHash, typename _Unused,
943 typename _RehashPolicy, typename _Traits>
944 template<typename _InputIterator, typename _NodeGetter>
945 void
946 _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
947 _Hash, _RangeHash, _Unused,
948 _RehashPolicy, _Traits>::
949 _M_insert_range(_InputIterator __first, _InputIterator __last,
950 const _NodeGetter& __node_gen, true_type __uks)
951 {
952 __hashtable& __h = _M_conjure_hashtable();
953 for (; __first != __last; ++__first)
954 __h._M_insert(*__first, __node_gen, __uks);
955 }
956
957 template<typename _Key, typename _Value, typename _Alloc,
958 typename _ExtractKey, typename _Equal,
959 typename _Hash, typename _RangeHash, typename _Unused,
960 typename _RehashPolicy, typename _Traits>
961 template<typename _InputIterator, typename _NodeGetter>
962 void
963 _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
964 _Hash, _RangeHash, _Unused,
965 _RehashPolicy, _Traits>::
966 _M_insert_range(_InputIterator __first, _InputIterator __last,
967 const _NodeGetter& __node_gen, false_type __uks)
968 {
969 using __rehash_type = typename __hashtable::__rehash_type;
970 using __rehash_state = typename __hashtable::__rehash_state;
971 using pair_type = std::pair<bool, std::size_t>;
972
973 size_type __n_elt = __detail::__distance_fw(__first, __last);
974 if (__n_elt == 0)
975 return;
976
977 __hashtable& __h = _M_conjure_hashtable();
978 __rehash_type& __rehash = __h._M_rehash_policy;
979 const __rehash_state& __saved_state = __rehash._M_state();
980 pair_type __do_rehash = __rehash._M_need_rehash(__h._M_bucket_count,
981 __h._M_element_count,
982 __n_elt);
983
984 if (__do_rehash.first)
985 __h._M_rehash(__do_rehash.second, __saved_state);
986
987 for (; __first != __last; ++__first)
988 __h._M_insert(*__first, __node_gen, __uks);
989 }
990
991 /**
992 * Primary class template _Insert.
993 *
994 * Defines @c insert member functions that depend on _Hashtable policies,
995 * via partial specializations.
996 */
997 template<typename _Key, typename _Value, typename _Alloc,
998 typename _ExtractKey, typename _Equal,
999 typename _Hash, typename _RangeHash, typename _Unused,
1000 typename _RehashPolicy, typename _Traits,
1001 bool _Constant_iterators = _Traits::__constant_iterators::value>
1002 struct _Insert;
1003
1004 /// Specialization.
1005 template<typename _Key, typename _Value, typename _Alloc,
1006 typename _ExtractKey, typename _Equal,
1007 typename _Hash, typename _RangeHash, typename _Unused,
1008 typename _RehashPolicy, typename _Traits>
1009 struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1010 _Hash, _RangeHash, _Unused,
1011 _RehashPolicy, _Traits, true>
1012 : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1013 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>
1014 {
1015 using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
1016 _Equal, _Hash, _RangeHash, _Unused,
1017 _RehashPolicy, _Traits>;
1018
1019 using value_type = typename __base_type::value_type;
1020 using iterator = typename __base_type::iterator;
1021 using const_iterator = typename __base_type::const_iterator;
1022 using __ireturn_type = typename __base_type::__ireturn_type;
1023
1024 using __unique_keys = typename __base_type::__unique_keys;
1025 using __hashtable = typename __base_type::__hashtable;
1026 using __node_gen_type = typename __base_type::__node_gen_type;
1027
1028 using __base_type::insert;
1029
1030 __ireturn_type
1031 insert(value_type&& __v)
1032 {
1033 __hashtable& __h = this->_M_conjure_hashtable();
1034 __node_gen_type __node_gen(__h);
1035 return __h._M_insert(std::move(__v), __node_gen, __unique_keys{});
1036 }
1037
1038 iterator
1039 insert(const_iterator __hint, value_type&& __v)
1040 {
1041 __hashtable& __h = this->_M_conjure_hashtable();
1042 __node_gen_type __node_gen(__h);
1043 return __h._M_insert(__hint, std::move(__v), __node_gen,
1044 __unique_keys{});
1045 }
1046 };
1047
1048 /// Specialization.
1049 template<typename _Key, typename _Value, typename _Alloc,
1050 typename _ExtractKey, typename _Equal,
1051 typename _Hash, typename _RangeHash, typename _Unused,
1052 typename _RehashPolicy, typename _Traits>
1053 struct _Insert<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1054 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
1055 : public _Insert_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1056 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>
1057 {
1058 using __base_type = _Insert_base<_Key, _Value, _Alloc, _ExtractKey,
1059 _Equal, _Hash, _RangeHash, _Unused,
1060 _RehashPolicy, _Traits>;
1061 using value_type = typename __base_type::value_type;
1062 using iterator = typename __base_type::iterator;
1063 using const_iterator = typename __base_type::const_iterator;
1064
1065 using __unique_keys = typename __base_type::__unique_keys;
1066 using __hashtable = typename __base_type::__hashtable;
1067 using __ireturn_type = typename __base_type::__ireturn_type;
1068
1069 using __base_type::insert;
1070
1071 template<typename _Pair>
1072 using __is_cons = std::is_constructible<value_type, _Pair&&>;
1073
1074 template<typename _Pair>
1075 using _IFcons = std::enable_if<__is_cons<_Pair>::value>;
1076
1077 template<typename _Pair>
1078 using _IFconsp = typename _IFcons<_Pair>::type;
1079
1080 template<typename _Pair, typename = _IFconsp<_Pair>>
1081 __ireturn_type
1082 insert(_Pair&& __v)
1083 {
1084 __hashtable& __h = this->_M_conjure_hashtable();
1085 return __h._M_emplace(__unique_keys{}, std::forward<_Pair>(__v));
1086 }
1087
1088 template<typename _Pair, typename = _IFconsp<_Pair>>
1089 iterator
1090 insert(const_iterator __hint, _Pair&& __v)
1091 {
1092 __hashtable& __h = this->_M_conjure_hashtable();
1093 return __h._M_emplace(__hint, __unique_keys{},
1094 std::forward<_Pair>(__v));
1095 }
1096 };
1097
1098 template<typename _Policy>
1099 using __has_load_factor = typename _Policy::__has_load_factor;
1100
1101 /**
1102 * Primary class template _Rehash_base.
1103 *
1104 * Give hashtable the max_load_factor functions and reserve iff the
1105 * rehash policy supports it.
1106 */
1107 template<typename _Key, typename _Value, typename _Alloc,
1108 typename _ExtractKey, typename _Equal,
1109 typename _Hash, typename _RangeHash, typename _Unused,
1110 typename _RehashPolicy, typename _Traits,
1111 typename =
1112 __detected_or_t<false_type, __has_load_factor, _RehashPolicy>>
1113 struct _Rehash_base;
1114
1115 /// Specialization when rehash policy doesn't provide load factor management.
1116 template<typename _Key, typename _Value, typename _Alloc,
1117 typename _ExtractKey, typename _Equal,
1118 typename _Hash, typename _RangeHash, typename _Unused,
1119 typename _RehashPolicy, typename _Traits>
1120 struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1121 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits,
1122 false_type /* Has load factor */>
1123 {
1124 };
1125
1126 /// Specialization when rehash policy provide load factor management.
1127 template<typename _Key, typename _Value, typename _Alloc,
1128 typename _ExtractKey, typename _Equal,
1129 typename _Hash, typename _RangeHash, typename _Unused,
1130 typename _RehashPolicy, typename _Traits>
1131 struct _Rehash_base<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1132 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits,
1133 true_type /* Has load factor */>
1134 {
1135 private:
1136 using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey,
1137 _Equal, _Hash, _RangeHash, _Unused,
1138 _RehashPolicy, _Traits>;
1139
1140 public:
1141 float
1142 max_load_factor() const noexcept
1143 {
1144 const __hashtable* __this = static_cast<const __hashtable*>(this);
1145 return __this->__rehash_policy().max_load_factor();
1146 }
1147
1148 void
1149 max_load_factor(float __z)
1150 {
1151 __hashtable* __this = static_cast<__hashtable*>(this);
1152 __this->__rehash_policy(_RehashPolicy(__z));
1153 }
1154
1155 void
1156 reserve(std::size_t __n)
1157 {
1158 __hashtable* __this = static_cast<__hashtable*>(this);
1159 __this->rehash(__this->__rehash_policy()._M_bkt_for_elements(__n));
1160 }
1161 };
1162
1163 /**
1164 * Primary class template _Hashtable_ebo_helper.
1165 *
1166 * Helper class using EBO when it is not forbidden (the type is not
1167 * final) and when it is worth it (the type is empty.)
1168 */
1169 template<int _Nm, typename _Tp,
1170 bool __use_ebo = !__is_final(_Tp) && __is_empty(_Tp)>
1171 struct _Hashtable_ebo_helper;
1172
1173 /// Specialization using EBO.
1174 template<int _Nm, typename _Tp>
1175 struct _Hashtable_ebo_helper<_Nm, _Tp, true>
1176 : private _Tp
1177 {
1178 _Hashtable_ebo_helper() noexcept(noexcept(_Tp())) : _Tp() { }
1179
1180 template<typename _OtherTp>
1181 _Hashtable_ebo_helper(_OtherTp&& __tp)
1182 : _Tp(std::forward<_OtherTp>(__tp))
1183 { }
1184
1185 const _Tp& _M_cget() const { return static_cast<const _Tp&>(*this); }
1186 _Tp& _M_get() { return static_cast<_Tp&>(*this); }
1187 };
1188
1189 /// Specialization not using EBO.
1190 template<int _Nm, typename _Tp>
1191 struct _Hashtable_ebo_helper<_Nm, _Tp, false>
1192 {
1193 _Hashtable_ebo_helper() = default;
1194
1195 template<typename _OtherTp>
1196 _Hashtable_ebo_helper(_OtherTp&& __tp)
1197 : _M_tp(std::forward<_OtherTp>(__tp))
1198 { }
1199
1200 const _Tp& _M_cget() const { return _M_tp; }
1201 _Tp& _M_get() { return _M_tp; }
1202
1203 private:
1204 _Tp _M_tp{};
1205 };
1206
1207 /**
1208 * Primary class template _Local_iterator_base.
1209 *
1210 * Base class for local iterators, used to iterate within a bucket
1211 * but not between buckets.
1212 */
1213 template<typename _Key, typename _Value, typename _ExtractKey,
1214 typename _Hash, typename _RangeHash, typename _Unused,
1215 bool __cache_hash_code>
1216 struct _Local_iterator_base;
1217
1218 /**
1219 * Primary class template _Hash_code_base.
1220 *
1221 * Encapsulates two policy issues that aren't quite orthogonal.
1222 * (1) the difference between using a ranged hash function and using
1223 * the combination of a hash function and a range-hashing function.
1224 * In the former case we don't have such things as hash codes, so
1225 * we have a dummy type as placeholder.
1226 * (2) Whether or not we cache hash codes. Caching hash codes is
1227 * meaningless if we have a ranged hash function.
1228 *
1229 * We also put the key extraction objects here, for convenience.
1230 * Each specialization derives from one or more of the template
1231 * parameters to benefit from Ebo. This is important as this type
1232 * is inherited in some cases by the _Local_iterator_base type used
1233 * to implement local_iterator and const_local_iterator. As with
1234 * any iterator type we prefer to make it as small as possible.
1235 */
1236 template<typename _Key, typename _Value, typename _ExtractKey,
1237 typename _Hash, typename _RangeHash, typename _Unused,
1238 bool __cache_hash_code>
1239 struct _Hash_code_base
1240 : private _Hashtable_ebo_helper<1, _Hash>
1241 {
1242 private:
1243 using __ebo_hash = _Hashtable_ebo_helper<1, _Hash>;
1244
1245 // Gives the local iterator implementation access to _M_bucket_index().
1246 friend struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1247 _Hash, _RangeHash, _Unused, false>;
1248
1249 public:
1250 typedef _Hash hasher;
1251
1252 hasher
1253 hash_function() const
1254 { return _M_hash(); }
1255
1256 protected:
1257 typedef std::size_t __hash_code;
1258
1259 // We need the default constructor for the local iterators and _Hashtable
1260 // default constructor.
1261 _Hash_code_base() = default;
1262
1263 _Hash_code_base(const _Hash& __hash) : __ebo_hash(__hash) { }
1264
1265 __hash_code
1266 _M_hash_code(const _Key& __k) const
1267 {
1268 static_assert(__is_invocable<const _Hash&, const _Key&>{},
1269 "hash function must be invocable with an argument of key type");
1270 return _M_hash()(__k);
1271 }
1272
1273 template<typename _Kt>
1274 __hash_code
1275 _M_hash_code_tr(const _Kt& __k) const
1276 {
1277 static_assert(__is_invocable<const _Hash&, const _Kt&>{},
1278 "hash function must be invocable with an argument of key type");
1279 return _M_hash()(__k);
1280 }
1281
1282 __hash_code
1283 _M_hash_code(const _Hash&,
1284 const _Hash_node_value<_Value, true>& __n) const
1285 { return __n._M_hash_code; }
1286
1287 // Compute hash code using _Hash as __n _M_hash_code, if present, was
1288 // computed using _H2.
1289 template<typename _H2>
1290 __hash_code
1291 _M_hash_code(const _H2&,
1292 const _Hash_node_value<_Value, __cache_hash_code>& __n) const
1293 { return _M_hash_code(_ExtractKey{}(__n._M_v())); }
1294
1295 __hash_code
1296 _M_hash_code(const _Hash_node_value<_Value, false>& __n) const
1297 { return _M_hash_code(_ExtractKey{}(__n._M_v())); }
1298
1299 __hash_code
1300 _M_hash_code(const _Hash_node_value<_Value, true>& __n) const
1301 { return __n._M_hash_code; }
1302
1303 std::size_t
1304 _M_bucket_index(__hash_code __c, std::size_t __bkt_count) const
1305 { return _RangeHash{}(__c, __bkt_count); }
1306
1307 std::size_t
1308 _M_bucket_index(const _Hash_node_value<_Value, false>& __n,
1309 std::size_t __bkt_count) const
1310 noexcept( noexcept(declval<const _Hash&>()(declval<const _Key&>()))
1311 && noexcept(declval<const _RangeHash&>()((__hash_code)0,
1312 (std::size_t)0)) )
1313 {
1314 return _RangeHash{}(_M_hash_code(_ExtractKey{}(__n._M_v())),
1315 __bkt_count);
1316 }
1317
1318 std::size_t
1319 _M_bucket_index(const _Hash_node_value<_Value, true>& __n,
1320 std::size_t __bkt_count) const
1321 noexcept( noexcept(declval<const _RangeHash&>()((__hash_code)0,
1322 (std::size_t)0)) )
1323 { return _RangeHash{}(__n._M_hash_code, __bkt_count); }
1324
1325 void
1326 _M_store_code(_Hash_node_code_cache<false>&, __hash_code) const
1327 { }
1328
1329 void
1330 _M_copy_code(_Hash_node_code_cache<false>&,
1331 const _Hash_node_code_cache<false>&) const
1332 { }
1333
1334 void
1335 _M_store_code(_Hash_node_code_cache<true>& __n, __hash_code __c) const
1336 { __n._M_hash_code = __c; }
1337
1338 void
1339 _M_copy_code(_Hash_node_code_cache<true>& __to,
1340 const _Hash_node_code_cache<true>& __from) const
1341 { __to._M_hash_code = __from._M_hash_code; }
1342
1343 void
1344 _M_swap(_Hash_code_base& __x)
1345 { std::swap(__ebo_hash::_M_get(), __x.__ebo_hash::_M_get()); }
1346
1347 const _Hash&
1348 _M_hash() const { return __ebo_hash::_M_cget(); }
1349 };
1350
1351 /// Partial specialization used when nodes contain a cached hash code.
1352 template<typename _Key, typename _Value, typename _ExtractKey,
1353 typename _Hash, typename _RangeHash, typename _Unused>
1354 struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1355 _Hash, _RangeHash, _Unused, true>
1356 : public _Node_iterator_base<_Value, true>
1357 {
1358 protected:
1359 using __base_node_iter = _Node_iterator_base<_Value, true>;
1360 using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1361 _Hash, _RangeHash, _Unused, true>;
1362
1363 _Local_iterator_base() = default;
1364 _Local_iterator_base(const __hash_code_base&,
1365 _Hash_node<_Value, true>* __p,
1366 std::size_t __bkt, std::size_t __bkt_count)
1367 : __base_node_iter(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
1368 { }
1369
1370 void
1371 _M_incr()
1372 {
1373 __base_node_iter::_M_incr();
1374 if (this->_M_cur)
1375 {
1376 std::size_t __bkt
1377 = _RangeHash{}(this->_M_cur->_M_hash_code, _M_bucket_count);
1378 if (__bkt != _M_bucket)
1379 this->_M_cur = nullptr;
1380 }
1381 }
1382
1383 std::size_t _M_bucket;
1384 std::size_t _M_bucket_count;
1385
1386 public:
1387 std::size_t
1388 _M_get_bucket() const { return _M_bucket; } // for debug mode
1389 };
1390
1391 // Uninitialized storage for a _Hash_code_base.
1392 // This type is DefaultConstructible and Assignable even if the
1393 // _Hash_code_base type isn't, so that _Local_iterator_base<..., false>
1394 // can be DefaultConstructible and Assignable.
1395 template<typename _Tp, bool _IsEmpty = std::is_empty<_Tp>::value>
1396 struct _Hash_code_storage
1397 {
1398 __gnu_cxx::__aligned_buffer<_Tp> _M_storage;
1399
1400 _Tp*
1401 _M_h() { return _M_storage._M_ptr(); }
1402
1403 const _Tp*
1404 _M_h() const { return _M_storage._M_ptr(); }
1405 };
1406
1407 // Empty partial specialization for empty _Hash_code_base types.
1408 template<typename _Tp>
1409 struct _Hash_code_storage<_Tp, true>
1410 {
1411 static_assert( std::is_empty<_Tp>::value, "Type must be empty" );
1412
1413 // As _Tp is an empty type there will be no bytes written/read through
1414 // the cast pointer, so no strict-aliasing violation.
1415 _Tp*
1416 _M_h() { return reinterpret_cast<_Tp*>(this); }
1417
1418 const _Tp*
1419 _M_h() const { return reinterpret_cast<const _Tp*>(this); }
1420 };
1421
1422 template<typename _Key, typename _Value, typename _ExtractKey,
1423 typename _Hash, typename _RangeHash, typename _Unused>
1424 using __hash_code_for_local_iter
1425 = _Hash_code_storage<_Hash_code_base<_Key, _Value, _ExtractKey,
1426 _Hash, _RangeHash, _Unused, false>>;
1427
1428 // Partial specialization used when hash codes are not cached
1429 template<typename _Key, typename _Value, typename _ExtractKey,
1430 typename _Hash, typename _RangeHash, typename _Unused>
1431 struct _Local_iterator_base<_Key, _Value, _ExtractKey,
1432 _Hash, _RangeHash, _Unused, false>
1433 : __hash_code_for_local_iter<_Key, _Value, _ExtractKey, _Hash, _RangeHash,
1434 _Unused>
1435 , _Node_iterator_base<_Value, false>
1436 {
1437 protected:
1438 using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1439 _Hash, _RangeHash, _Unused, false>;
1440 using __node_iter_base = _Node_iterator_base<_Value, false>;
1441
1442 _Local_iterator_base() : _M_bucket_count(-1) { }
1443
1444 _Local_iterator_base(const __hash_code_base& __base,
1445 _Hash_node<_Value, false>* __p,
1446 std::size_t __bkt, std::size_t __bkt_count)
1447 : __node_iter_base(__p), _M_bucket(__bkt), _M_bucket_count(__bkt_count)
1448 { _M_init(__base); }
1449
1450 ~_Local_iterator_base()
1451 {
1452 if (_M_bucket_count != size_t(-1))
1453 _M_destroy();
1454 }
1455
1456 _Local_iterator_base(const _Local_iterator_base& __iter)
1457 : __node_iter_base(__iter._M_cur), _M_bucket(__iter._M_bucket)
1458 , _M_bucket_count(__iter._M_bucket_count)
1459 {
1460 if (_M_bucket_count != size_t(-1))
1461 _M_init(base: *__iter._M_h());
1462 }
1463
1464 _Local_iterator_base&
1465 operator=(const _Local_iterator_base& __iter)
1466 {
1467 if (_M_bucket_count != -1)
1468 _M_destroy();
1469 this->_M_cur = __iter._M_cur;
1470 _M_bucket = __iter._M_bucket;
1471 _M_bucket_count = __iter._M_bucket_count;
1472 if (_M_bucket_count != -1)
1473 _M_init(base: *__iter._M_h());
1474 return *this;
1475 }
1476
1477 void
1478 _M_incr()
1479 {
1480 __node_iter_base::_M_incr();
1481 if (this->_M_cur)
1482 {
1483 std::size_t __bkt = this->_M_h()->_M_bucket_index(*this->_M_cur,
1484 _M_bucket_count);
1485 if (__bkt != _M_bucket)
1486 this->_M_cur = nullptr;
1487 }
1488 }
1489
1490 std::size_t _M_bucket;
1491 std::size_t _M_bucket_count;
1492
1493 void
1494 _M_init(const __hash_code_base& __base)
1495 { ::new(this->_M_h()) __hash_code_base(__base); }
1496
1497 void
1498 _M_destroy() { this->_M_h()->~__hash_code_base(); }
1499
1500 public:
1501 std::size_t
1502 _M_get_bucket() const { return _M_bucket; } // for debug mode
1503 };
1504
1505 /// local iterators
1506 template<typename _Key, typename _Value, typename _ExtractKey,
1507 typename _Hash, typename _RangeHash, typename _Unused,
1508 bool __constant_iterators, bool __cache>
1509 struct _Local_iterator
1510 : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1511 _Hash, _RangeHash, _Unused, __cache>
1512 {
1513 private:
1514 using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1515 _Hash, _RangeHash, _Unused, __cache>;
1516 using __hash_code_base = typename __base_type::__hash_code_base;
1517
1518 public:
1519 using value_type = _Value;
1520 using pointer = __conditional_t<__constant_iterators,
1521 const value_type*, value_type*>;
1522 using reference = __conditional_t<__constant_iterators,
1523 const value_type&, value_type&>;
1524 using difference_type = ptrdiff_t;
1525 using iterator_category = forward_iterator_tag;
1526
1527 _Local_iterator() = default;
1528
1529 _Local_iterator(const __hash_code_base& __base,
1530 _Hash_node<_Value, __cache>* __n,
1531 std::size_t __bkt, std::size_t __bkt_count)
1532 : __base_type(__base, __n, __bkt, __bkt_count)
1533 { }
1534
1535 reference
1536 operator*() const
1537 { return this->_M_cur->_M_v(); }
1538
1539 pointer
1540 operator->() const
1541 { return this->_M_cur->_M_valptr(); }
1542
1543 _Local_iterator&
1544 operator++()
1545 {
1546 this->_M_incr();
1547 return *this;
1548 }
1549
1550 _Local_iterator
1551 operator++(int)
1552 {
1553 _Local_iterator __tmp(*this);
1554 this->_M_incr();
1555 return __tmp;
1556 }
1557 };
1558
1559 /// local const_iterators
1560 template<typename _Key, typename _Value, typename _ExtractKey,
1561 typename _Hash, typename _RangeHash, typename _Unused,
1562 bool __constant_iterators, bool __cache>
1563 struct _Local_const_iterator
1564 : public _Local_iterator_base<_Key, _Value, _ExtractKey,
1565 _Hash, _RangeHash, _Unused, __cache>
1566 {
1567 private:
1568 using __base_type = _Local_iterator_base<_Key, _Value, _ExtractKey,
1569 _Hash, _RangeHash, _Unused, __cache>;
1570 using __hash_code_base = typename __base_type::__hash_code_base;
1571
1572 public:
1573 typedef _Value value_type;
1574 typedef const value_type* pointer;
1575 typedef const value_type& reference;
1576 typedef std::ptrdiff_t difference_type;
1577 typedef std::forward_iterator_tag iterator_category;
1578
1579 _Local_const_iterator() = default;
1580
1581 _Local_const_iterator(const __hash_code_base& __base,
1582 _Hash_node<_Value, __cache>* __n,
1583 std::size_t __bkt, std::size_t __bkt_count)
1584 : __base_type(__base, __n, __bkt, __bkt_count)
1585 { }
1586
1587 _Local_const_iterator(const _Local_iterator<_Key, _Value, _ExtractKey,
1588 _Hash, _RangeHash, _Unused,
1589 __constant_iterators,
1590 __cache>& __x)
1591 : __base_type(__x)
1592 { }
1593
1594 reference
1595 operator*() const
1596 { return this->_M_cur->_M_v(); }
1597
1598 pointer
1599 operator->() const
1600 { return this->_M_cur->_M_valptr(); }
1601
1602 _Local_const_iterator&
1603 operator++()
1604 {
1605 this->_M_incr();
1606 return *this;
1607 }
1608
1609 _Local_const_iterator
1610 operator++(int)
1611 {
1612 _Local_const_iterator __tmp(*this);
1613 this->_M_incr();
1614 return __tmp;
1615 }
1616 };
1617
1618 /**
1619 * Primary class template _Hashtable_base.
1620 *
1621 * Helper class adding management of _Equal functor to
1622 * _Hash_code_base type.
1623 *
1624 * Base class templates are:
1625 * - __detail::_Hash_code_base
1626 * - __detail::_Hashtable_ebo_helper
1627 */
1628 template<typename _Key, typename _Value, typename _ExtractKey,
1629 typename _Equal, typename _Hash, typename _RangeHash,
1630 typename _Unused, typename _Traits>
1631 struct _Hashtable_base
1632 : public _Hash_code_base<_Key, _Value, _ExtractKey, _Hash, _RangeHash,
1633 _Unused, _Traits::__hash_cached::value>,
1634 private _Hashtable_ebo_helper<0, _Equal>
1635 {
1636 public:
1637 typedef _Key key_type;
1638 typedef _Value value_type;
1639 typedef _Equal key_equal;
1640 typedef std::size_t size_type;
1641 typedef std::ptrdiff_t difference_type;
1642
1643 using __traits_type = _Traits;
1644 using __hash_cached = typename __traits_type::__hash_cached;
1645
1646 using __hash_code_base = _Hash_code_base<_Key, _Value, _ExtractKey,
1647 _Hash, _RangeHash, _Unused,
1648 __hash_cached::value>;
1649
1650 using __hash_code = typename __hash_code_base::__hash_code;
1651
1652 private:
1653 using _EqualEBO = _Hashtable_ebo_helper<0, _Equal>;
1654
1655 static bool
1656 _S_equals(__hash_code, const _Hash_node_code_cache<false>&)
1657 { return true; }
1658
1659 static bool
1660 _S_node_equals(const _Hash_node_code_cache<false>&,
1661 const _Hash_node_code_cache<false>&)
1662 { return true; }
1663
1664 static bool
1665 _S_equals(__hash_code __c, const _Hash_node_code_cache<true>& __n)
1666 { return __c == __n._M_hash_code; }
1667
1668 static bool
1669 _S_node_equals(const _Hash_node_code_cache<true>& __lhn,
1670 const _Hash_node_code_cache<true>& __rhn)
1671 { return __lhn._M_hash_code == __rhn._M_hash_code; }
1672
1673 protected:
1674 _Hashtable_base() = default;
1675
1676 _Hashtable_base(const _Hash& __hash, const _Equal& __eq)
1677 : __hash_code_base(__hash), _EqualEBO(__eq)
1678 { }
1679
1680 bool
1681 _M_key_equals(const _Key& __k,
1682 const _Hash_node_value<_Value,
1683 __hash_cached::value>& __n) const
1684 {
1685 static_assert(__is_invocable<const _Equal&, const _Key&, const _Key&>{},
1686 "key equality predicate must be invocable with two arguments of "
1687 "key type");
1688 return _M_eq()(__k, _ExtractKey{}(__n._M_v()));
1689 }
1690
1691 template<typename _Kt>
1692 bool
1693 _M_key_equals_tr(const _Kt& __k,
1694 const _Hash_node_value<_Value,
1695 __hash_cached::value>& __n) const
1696 {
1697 static_assert(
1698 __is_invocable<const _Equal&, const _Kt&, const _Key&>{},
1699 "key equality predicate must be invocable with two arguments of "
1700 "key type");
1701 return _M_eq()(__k, _ExtractKey{}(__n._M_v()));
1702 }
1703
1704 bool
1705 _M_equals(const _Key& __k, __hash_code __c,
1706 const _Hash_node_value<_Value, __hash_cached::value>& __n) const
1707 { return _S_equals(__c, __n) && _M_key_equals(__k, __n); }
1708
1709 template<typename _Kt>
1710 bool
1711 _M_equals_tr(const _Kt& __k, __hash_code __c,
1712 const _Hash_node_value<_Value,
1713 __hash_cached::value>& __n) const
1714 { return _S_equals(__c, __n) && _M_key_equals_tr(__k, __n); }
1715
1716 bool
1717 _M_node_equals(
1718 const _Hash_node_value<_Value, __hash_cached::value>& __lhn,
1719 const _Hash_node_value<_Value, __hash_cached::value>& __rhn) const
1720 {
1721 return _S_node_equals(__lhn, __rhn)
1722 && _M_key_equals(k: _ExtractKey{}(__lhn._M_v()), n: __rhn);
1723 }
1724
1725 void
1726 _M_swap(_Hashtable_base& __x)
1727 {
1728 __hash_code_base::_M_swap(__x);
1729 std::swap(_EqualEBO::_M_get(), __x._EqualEBO::_M_get());
1730 }
1731
1732 const _Equal&
1733 _M_eq() const { return _EqualEBO::_M_cget(); }
1734 };
1735
1736 /**
1737 * Primary class template _Equality.
1738 *
1739 * This is for implementing equality comparison for unordered
1740 * containers, per N3068, by John Lakos and Pablo Halpern.
1741 * Algorithmically, we follow closely the reference implementations
1742 * therein.
1743 */
1744 template<typename _Key, typename _Value, typename _Alloc,
1745 typename _ExtractKey, typename _Equal,
1746 typename _Hash, typename _RangeHash, typename _Unused,
1747 typename _RehashPolicy, typename _Traits,
1748 bool _Unique_keys = _Traits::__unique_keys::value>
1749 struct _Equality;
1750
1751 /// unordered_map and unordered_set specializations.
1752 template<typename _Key, typename _Value, typename _Alloc,
1753 typename _ExtractKey, typename _Equal,
1754 typename _Hash, typename _RangeHash, typename _Unused,
1755 typename _RehashPolicy, typename _Traits>
1756 struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1757 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>
1758 {
1759 using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1760 _Hash, _RangeHash, _Unused,
1761 _RehashPolicy, _Traits>;
1762
1763 bool
1764 _M_equal(const __hashtable&) const;
1765 };
1766
1767 template<typename _Key, typename _Value, typename _Alloc,
1768 typename _ExtractKey, typename _Equal,
1769 typename _Hash, typename _RangeHash, typename _Unused,
1770 typename _RehashPolicy, typename _Traits>
1771 bool
1772 _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1773 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, true>::
1774 _M_equal(const __hashtable& __other) const
1775 {
1776 using __node_type = typename __hashtable::__node_type;
1777 const __hashtable* __this = static_cast<const __hashtable*>(this);
1778 if (__this->size() != __other.size())
1779 return false;
1780
1781 for (auto __itx = __this->begin(); __itx != __this->end(); ++__itx)
1782 {
1783 std::size_t __ybkt = __other._M_bucket_index(*__itx._M_cur);
1784 auto __prev_n = __other._M_buckets[__ybkt];
1785 if (!__prev_n)
1786 return false;
1787
1788 for (__node_type* __n = static_cast<__node_type*>(__prev_n->_M_nxt);;
1789 __n = __n->_M_next())
1790 {
1791 if (__n->_M_v() == *__itx)
1792 break;
1793
1794 if (!__n->_M_nxt
1795 || __other._M_bucket_index(*__n->_M_next()) != __ybkt)
1796 return false;
1797 }
1798 }
1799
1800 return true;
1801 }
1802
1803 /// unordered_multiset and unordered_multimap specializations.
1804 template<typename _Key, typename _Value, typename _Alloc,
1805 typename _ExtractKey, typename _Equal,
1806 typename _Hash, typename _RangeHash, typename _Unused,
1807 typename _RehashPolicy, typename _Traits>
1808 struct _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1809 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>
1810 {
1811 using __hashtable = _Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1812 _Hash, _RangeHash, _Unused,
1813 _RehashPolicy, _Traits>;
1814
1815 bool
1816 _M_equal(const __hashtable&) const;
1817 };
1818
1819 template<typename _Key, typename _Value, typename _Alloc,
1820 typename _ExtractKey, typename _Equal,
1821 typename _Hash, typename _RangeHash, typename _Unused,
1822 typename _RehashPolicy, typename _Traits>
1823 bool
1824 _Equality<_Key, _Value, _Alloc, _ExtractKey, _Equal,
1825 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits, false>::
1826 _M_equal(const __hashtable& __other) const
1827 {
1828 using __node_type = typename __hashtable::__node_type;
1829 const __hashtable* __this = static_cast<const __hashtable*>(this);
1830 if (__this->size() != __other.size())
1831 return false;
1832
1833 for (auto __itx = __this->begin(); __itx != __this->end();)
1834 {
1835 std::size_t __x_count = 1;
1836 auto __itx_end = __itx;
1837 for (++__itx_end; __itx_end != __this->end()
1838 && __this->key_eq()(_ExtractKey{}(*__itx),
1839 _ExtractKey{}(*__itx_end));
1840 ++__itx_end)
1841 ++__x_count;
1842
1843 std::size_t __ybkt = __other._M_bucket_index(*__itx._M_cur);
1844 auto __y_prev_n = __other._M_buckets[__ybkt];
1845 if (!__y_prev_n)
1846 return false;
1847
1848 __node_type* __y_n = static_cast<__node_type*>(__y_prev_n->_M_nxt);
1849 for (;;)
1850 {
1851 if (__this->key_eq()(_ExtractKey{}(__y_n->_M_v()),
1852 _ExtractKey{}(*__itx)))
1853 break;
1854
1855 auto __y_ref_n = __y_n;
1856 for (__y_n = __y_n->_M_next(); __y_n; __y_n = __y_n->_M_next())
1857 if (!__other._M_node_equals(*__y_ref_n, *__y_n))
1858 break;
1859
1860 if (!__y_n || __other._M_bucket_index(*__y_n) != __ybkt)
1861 return false;
1862 }
1863
1864 typename __hashtable::const_iterator __ity(__y_n);
1865 for (auto __ity_end = __ity; __ity_end != __other.end(); ++__ity_end)
1866 if (--__x_count == 0)
1867 break;
1868
1869 if (__x_count != 0)
1870 return false;
1871
1872 if (!std::is_permutation(__itx, __itx_end, __ity))
1873 return false;
1874
1875 __itx = __itx_end;
1876 }
1877 return true;
1878 }
1879
1880 /**
1881 * This type deals with all allocation and keeps an allocator instance
1882 * through inheritance to benefit from EBO when possible.
1883 */
1884 template<typename _NodeAlloc>
1885 struct _Hashtable_alloc : private _Hashtable_ebo_helper<0, _NodeAlloc>
1886 {
1887 private:
1888 using __ebo_node_alloc = _Hashtable_ebo_helper<0, _NodeAlloc>;
1889
1890 template<typename>
1891 struct __get_value_type;
1892 template<typename _Val, bool _Cache_hash_code>
1893 struct __get_value_type<_Hash_node<_Val, _Cache_hash_code>>
1894 { using type = _Val; };
1895
1896 public:
1897 using __node_type = typename _NodeAlloc::value_type;
1898 using __node_alloc_type = _NodeAlloc;
1899 // Use __gnu_cxx to benefit from _S_always_equal and al.
1900 using __node_alloc_traits = __gnu_cxx::__alloc_traits<__node_alloc_type>;
1901
1902 using __value_alloc_traits = typename __node_alloc_traits::template
1903 rebind_traits<typename __get_value_type<__node_type>::type>;
1904
1905 using __node_ptr = __node_type*;
1906 using __node_base = _Hash_node_base;
1907 using __node_base_ptr = __node_base*;
1908 using __buckets_alloc_type =
1909 __alloc_rebind<__node_alloc_type, __node_base_ptr>;
1910 using __buckets_alloc_traits = std::allocator_traits<__buckets_alloc_type>;
1911 using __buckets_ptr = __node_base_ptr*;
1912
1913 _Hashtable_alloc() = default;
1914 _Hashtable_alloc(const _Hashtable_alloc&) = default;
1915 _Hashtable_alloc(_Hashtable_alloc&&) = default;
1916
1917 template<typename _Alloc>
1918 _Hashtable_alloc(_Alloc&& __a)
1919 : __ebo_node_alloc(std::forward<_Alloc>(__a))
1920 { }
1921
1922 __node_alloc_type&
1923 _M_node_allocator()
1924 { return __ebo_node_alloc::_M_get(); }
1925
1926 const __node_alloc_type&
1927 _M_node_allocator() const
1928 { return __ebo_node_alloc::_M_cget(); }
1929
1930 // Allocate a node and construct an element within it.
1931 template<typename... _Args>
1932 __node_ptr
1933 _M_allocate_node(_Args&&... __args);
1934
1935 // Destroy the element within a node and deallocate the node.
1936 void
1937 _M_deallocate_node(__node_ptr __n);
1938
1939 // Deallocate a node.
1940 void
1941 _M_deallocate_node_ptr(__node_ptr __n);
1942
1943 // Deallocate the linked list of nodes pointed to by __n.
1944 // The elements within the nodes are destroyed.
1945 void
1946 _M_deallocate_nodes(__node_ptr __n);
1947
1948 __buckets_ptr
1949 _M_allocate_buckets(std::size_t __bkt_count);
1950
1951 void
1952 _M_deallocate_buckets(__buckets_ptr, std::size_t __bkt_count);
1953 };
1954
1955 // Definitions of class template _Hashtable_alloc's out-of-line member
1956 // functions.
1957 template<typename _NodeAlloc>
1958 template<typename... _Args>
1959 auto
1960 _Hashtable_alloc<_NodeAlloc>::_M_allocate_node(_Args&&... __args)
1961 -> __node_ptr
1962 {
1963 auto __nptr = __node_alloc_traits::allocate(_M_node_allocator(), 1);
1964 __node_ptr __n = std::__to_address(__nptr);
1965 __try
1966 {
1967 ::new ((void*)__n) __node_type;
1968 __node_alloc_traits::construct(_M_node_allocator(),
1969 __n->_M_valptr(),
1970 std::forward<_Args>(__args)...);
1971 return __n;
1972 }
1973 __catch(...)
1974 {
1975 __node_alloc_traits::deallocate(_M_node_allocator(), __nptr, 1);
1976 __throw_exception_again;
1977 }
1978 }
1979
1980 template<typename _NodeAlloc>
1981 void
1982 _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node(__node_ptr __n)
1983 {
1984 __node_alloc_traits::destroy(_M_node_allocator(), __n->_M_valptr());
1985 _M_deallocate_node_ptr(__n);
1986 }
1987
1988 template<typename _NodeAlloc>
1989 void
1990 _Hashtable_alloc<_NodeAlloc>::_M_deallocate_node_ptr(__node_ptr __n)
1991 {
1992 typedef typename __node_alloc_traits::pointer _Ptr;
1993 auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__n);
1994 __n->~__node_type();
1995 __node_alloc_traits::deallocate(_M_node_allocator(), __ptr, 1);
1996 }
1997
1998 template<typename _NodeAlloc>
1999 void
2000 _Hashtable_alloc<_NodeAlloc>::_M_deallocate_nodes(__node_ptr __n)
2001 {
2002 while (__n)
2003 {
2004 __node_ptr __tmp = __n;
2005 __n = __n->_M_next();
2006 _M_deallocate_node(n: __tmp);
2007 }
2008 }
2009
2010 template<typename _NodeAlloc>
2011 auto
2012 _Hashtable_alloc<_NodeAlloc>::_M_allocate_buckets(std::size_t __bkt_count)
2013 -> __buckets_ptr
2014 {
2015 __buckets_alloc_type __alloc(_M_node_allocator());
2016
2017 auto __ptr = __buckets_alloc_traits::allocate(__alloc, __bkt_count);
2018 __buckets_ptr __p = std::__to_address(__ptr);
2019 __builtin_memset(__p, 0, __bkt_count * sizeof(__node_base_ptr));
2020 return __p;
2021 }
2022
2023 template<typename _NodeAlloc>
2024 void
2025 _Hashtable_alloc<_NodeAlloc>::
2026 _M_deallocate_buckets(__buckets_ptr __bkts,
2027 std::size_t __bkt_count)
2028 {
2029 typedef typename __buckets_alloc_traits::pointer _Ptr;
2030 auto __ptr = std::pointer_traits<_Ptr>::pointer_to(*__bkts);
2031 __buckets_alloc_type __alloc(_M_node_allocator());
2032 __buckets_alloc_traits::deallocate(__alloc, __ptr, __bkt_count);
2033 }
2034
2035 ///@} hashtable-detail
2036} // namespace __detail
2037/// @endcond
2038_GLIBCXX_END_NAMESPACE_VERSION
2039} // namespace std
2040
2041#endif // _HASHTABLE_POLICY_H
2042